From 12b6c292438cac17a19154335bb6066676876b20 Mon Sep 17 00:00:00 2001
From: Manan Solanki <76104205+Manan-09@users.noreply.github.com>
Date: Wed, 20 Sep 2023 01:23:53 +0530
Subject: [PATCH 0001/1338] #4367 Enhance Knapsack problem (#4368)

* Enhance Knapsack problem

* Linter solved

* Linter solved

* Remove DynamicProgrammingKnapsack file, duplicate of Knapsack file

* Add null input testcase

* Linter resolved

* Updated meaningful test names

* Add check for negative weightCapacity

* Linter resolved

* Linter resolved

* Add check for non-positive weight

* Linter resolved

* fix: use proper formatting

* fix: use proper formatting

* fix: use proper formatting (I hope this will work now)

Sorry for the previous mess.

* Code review comments

* Code review comments

* Code review comments

* Code review comments

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../DyanamicProgrammingKnapsack.java          | 36 ---------
 .../dynamicprogramming/Knapsack.java          | 69 ++++++++++------
 .../dynamicprogramming/KnapsackTest.java      | 81 +++++++++++++++++++
 3 files changed, 124 insertions(+), 62 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/DyanamicProgrammingKnapsack.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/DyanamicProgrammingKnapsack.java b/src/main/java/com/thealgorithms/dynamicprogramming/DyanamicProgrammingKnapsack.java
deleted file mode 100644
index 042dff375acd..000000000000
--- a/src/main/java/com/thealgorithms/dynamicprogramming/DyanamicProgrammingKnapsack.java
+++ /dev/null
@@ -1,36 +0,0 @@
-package com.thealgorithms.dynamicprogramming;
-
-// A Dynamic Programming based solution
-// for 0-1 Knapsack problem
-public class DyanamicProgrammingKnapsack {
-    // Returns the maximum value that can
-    // be put in a knapsack of capacity W
-    static int knapSack(int W, int[] wt, int[] val, int n) {
-        int i, w;
-        int[][] K = new int[n + 1][W + 1];
-
-        // Build table K[][] in bottom up manner
-        for (i = 0; i <= n; i++) {
-            for (w = 0; w <= W; w++) {
-                if (i == 0 || w == 0) {
-                    K[i][w] = 0;
-                } else if (wt[i - 1] <= w) {
-                    K[i][w] = Math.max(val[i - 1] + K[i - 1][w - wt[i - 1]], K[i - 1][w]);
-                } else {
-                    K[i][w] = K[i - 1][w];
-                }
-            }
-        }
-
-        return K[n][W];
-    }
-
-    // Driver code
-    public static void main(String[] args) {
-        int[] val = new int[] {60, 100, 120};
-        int[] wt = new int[] {10, 20, 30};
-        int W = 50;
-        int n = val.length;
-        System.out.println(knapSack(W, wt, val, n));
-    }
-}
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java b/src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java
index 712a028ee960..134561766830 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java
@@ -1,38 +1,55 @@
 package com.thealgorithms.dynamicprogramming;
 
+import java.util.Arrays;
+
 /**
- * A DynamicProgramming based solution for 0-1 Knapsack problem
+ * A Dynamic Programming based solution for the 0-1 Knapsack problem.
+ * This class provides a method, `knapSack`, that calculates the maximum value that can be
+ * obtained from a given set of items with weights and values, while not exceeding a
+ * given weight capacity.
+ *
+ * @see <a href="https://en.wikipedia.org/?title=0-1_Knapsack_problem">0-1 Knapsack Problem </a>
  */
-public class Knapsack {
+public final class Knapsack {
+
+    private Knapsack() {
+    }
 
-    private static int knapSack(int W, int[] wt, int[] val, int n) throws IllegalArgumentException {
-        if (wt == null || val == null) {
-            throw new IllegalArgumentException();
+    private static void throwIfInvalidInput(final int weightCapacity, final int[] weights, final int[] values) {
+        if (weightCapacity < 0) {
+            throw new IllegalArgumentException("Weight capacity should not be negative.");
         }
-        int i, w;
-        int[][] rv = new int[n + 1][W + 1]; // rv means return value
-
-        // Build table rv[][] in bottom up manner
-        for (i = 0; i <= n; i++) {
-            for (w = 0; w <= W; w++) {
-                if (i == 0 || w == 0) {
-                    rv[i][w] = 0;
-                } else if (wt[i - 1] <= w) {
-                    rv[i][w] = Math.max(val[i - 1] + rv[i - 1][w - wt[i - 1]], rv[i - 1][w]);
-                } else {
-                    rv[i][w] = rv[i - 1][w];
+        if (weights == null || values == null || weights.length != values.length) {
+            throw new IllegalArgumentException("Input arrays must not be null and must have the same length.");
+        }
+        if (Arrays.stream(weights).anyMatch(w -> w <= 0)) {
+            throw new IllegalArgumentException("Input array should not contain non-positive weight(s).");
+        }
+    }
+
+    /**
+     * Solves the 0-1 Knapsack problem using Dynamic Programming.
+     *
+     * @param weightCapacity The maximum weight capacity of the knapsack.
+     * @param weights        An array of item weights.
+     * @param values         An array of item values.
+     * @return The maximum value that can be obtained without exceeding the weight capacity.
+     * @throws IllegalArgumentException If the input arrays are null or have different lengths.
+     */
+    public static int knapSack(final int weightCapacity, final int[] weights, final int[] values) throws IllegalArgumentException {
+        throwIfInvalidInput(weightCapacity, weights, values);
+
+        // DP table to store the state of the maximum possible return for a given weight capacity.
+        int[] dp = new int[weightCapacity + 1];
+
+        for (int i = 0; i < values.length; i++) {
+            for (int w = weightCapacity; w > 0; w--) {
+                if (weights[i] <= w) {
+                    dp[w] = Math.max(dp[w], dp[w - weights[i]] + values[i]);
                 }
             }
         }
 
-        return rv[n][W];
-    }
-
-    // Driver program to test above function
-    public static void main(String[] args) {
-        int[] val = new int[] {50, 100, 130};
-        int[] wt = new int[] {10, 20, 40};
-        int W = 50;
-        System.out.println(knapSack(W, wt, val, val.length));
+        return dp[weightCapacity];
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java
new file mode 100644
index 000000000000..3ff733db7e15
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java
@@ -0,0 +1,81 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class KnapsackTest {
+    @Test
+    public void testKnapSackBasic() {
+        int[] weights = {2, 3, 4, 5};
+        int[] values = {3, 4, 5, 6};
+        int weightCapacity = 5;
+        int expected = 7; // Maximum value should be 7 (items 1 and 4).
+        int result = Knapsack.knapSack(weightCapacity, weights, values);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testKnapSackEmpty() {
+        int[] weights = {};
+        int[] values = {};
+        int weightCapacity = 10;
+        int expected = 0; // With no items, the result should be 0.
+        int result = Knapsack.knapSack(weightCapacity, weights, values);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testKnapSackNoCapacity() {
+        int[] weights = {2, 3, 4};
+        int[] values = {3, 4, 5};
+        int weightCapacity = 0;
+        int expected = 0; // With no capacity, the result should be 0.
+        int result = Knapsack.knapSack(weightCapacity, weights, values);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testKnapSackMaxCapacity() {
+        int[] weights = {2, 3, 4, 5};
+        int[] values = {3, 4, 5, 6};
+        int weightCapacity = 10;
+        int expected = 13; // Maximum value should be 13 (items 1, 3, and 4).
+        int result = Knapsack.knapSack(weightCapacity, weights, values);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testKnapSackThrowsForInputsOfDifferentLength() {
+        int[] weights = {2, 3, 4};
+        int[] values = {3, 4, 5, 6}; // Different length values array.
+        int weightCapacity = 5;
+        assertThrows(IllegalArgumentException.class, () -> { Knapsack.knapSack(weightCapacity, weights, values); });
+    }
+
+    @Test
+    public void testKnapSackThrowsForNullInputs() {
+        int[] weights = {2, 3, 4};
+        int[] values = {3, 4, 6};
+        int weightCapacity = 5;
+        assertThrows(IllegalArgumentException.class, () -> { Knapsack.knapSack(weightCapacity, null, values); });
+        assertThrows(IllegalArgumentException.class, () -> { Knapsack.knapSack(weightCapacity, weights, null); });
+    }
+
+    @Test
+    public void testKnapSackThrowsForNegativeCapacity() {
+        int[] weights = {2, 3, 4, 5};
+        int[] values = {3, 4, 5, 6};
+        int weightCapacity = -5;
+        assertThrows(IllegalArgumentException.class, () -> { Knapsack.knapSack(weightCapacity, weights, values); });
+    }
+
+    @Test
+    public void testKnapSackThrowsForNegativeWeight() {
+        int[] weights = {2, 0, 4};
+        int[] values = {3, 4, 6};
+        int weightCapacity = 5;
+        assertThrows(IllegalArgumentException.class, () -> { Knapsack.knapSack(weightCapacity, weights, values); });
+    }
+}

From 906cd877315774e59c527c09c842bc1891886ac8 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 20 Sep 2023 19:38:37 +0200
Subject: [PATCH 0002/1338] style: avoid wildcard imports (#4386)

* style: import `assertEquals` explicitly

* fix: import `assertThrows`
---
 src/test/java/com/thealgorithms/maths/FactorialTest.java | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/test/java/com/thealgorithms/maths/FactorialTest.java b/src/test/java/com/thealgorithms/maths/FactorialTest.java
index b22ad535a234..b38dc45589ee 100644
--- a/src/test/java/com/thealgorithms/maths/FactorialTest.java
+++ b/src/test/java/com/thealgorithms/maths/FactorialTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 

From fbe348b105a06258a81538023698117e2bb116cb Mon Sep 17 00:00:00 2001
From: Ansh Shah <60037118+govardhanshah456@users.noreply.github.com>
Date: Thu, 21 Sep 2023 11:35:26 +0530
Subject: [PATCH 0003/1338] #4382 Bug Fix (#4384)

* #4382 Bug Fix

* #4382 Bug Fix

* Made Requested Changes

* Made Requested Changes

* Made Requested Changes

* Made Requested Changes

* Made Requested Changes

* Made Requested Changes

* Made Requested Changes

* Update src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../misc/MedianOfRunningArray.java            |  42 +++--
 .../misc/MedianOfRunningArrayTest.java        | 161 ++++++++++++++++++
 2 files changed, 181 insertions(+), 22 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java

diff --git a/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java b/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
index 84dff89eaa8b..61fbfa82003f 100644
--- a/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
+++ b/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
@@ -8,13 +8,13 @@
  */
 public class MedianOfRunningArray {
 
-    private PriorityQueue<Integer> p1;
-    private PriorityQueue<Integer> p2;
+    private PriorityQueue<Integer> maxHeap;
+    private PriorityQueue<Integer> minHeap;
 
     // Constructor
     public MedianOfRunningArray() {
-        this.p1 = new PriorityQueue<>(Collections.reverseOrder()); // Max Heap
-        this.p2 = new PriorityQueue<>(); // Min Heap
+        this.maxHeap = new PriorityQueue<>(Collections.reverseOrder()); // Max Heap
+        this.minHeap = new PriorityQueue<>(); // Min Heap
     }
 
     /*
@@ -22,32 +22,30 @@ public MedianOfRunningArray() {
       and upper half to min heap
      */
     public void insert(Integer e) {
-        p2.add(e);
-        if (p2.size() - p1.size() > 1) {
-            p1.add(p2.remove());
+        if (!minHeap.isEmpty() && e < minHeap.peek()) {
+            maxHeap.offer(e);
+            if (maxHeap.size() > minHeap.size() + 1) {
+                minHeap.offer(maxHeap.poll());
+            }
+        } else {
+            minHeap.offer(e);
+            if (minHeap.size() > maxHeap.size() + 1) {
+                maxHeap.offer(minHeap.poll());
+            }
         }
     }
 
     /*
       Returns median at any given point
      */
-    public Integer median() {
-        if (p1.size() == p2.size()) {
-            return (p1.peek() + p2.peek()) / 2;
+    public double median() {
+        if (maxHeap.isEmpty() && minHeap.isEmpty()) {
+            throw new IllegalArgumentException("Enter at least 1 element, Median of empty list is not defined!");
         }
-        return p1.size() > p2.size() ? p1.peek() : p2.peek();
-    }
-
-    public static void main(String[] args) {
-        /*
-        Testing the median function
-         */
 
-        MedianOfRunningArray p = new MedianOfRunningArray();
-        int[] arr = {10, 7, 4, 9, 2, 3, 11, 17, 14};
-        for (int i = 0; i < 9; i++) {
-            p.insert(arr[i]);
-            System.out.print(p.median() + " ");
+        if (maxHeap.size() == minHeap.size()) {
+            return (maxHeap.peek() + minHeap.peek()) / 2.0;
         }
+        return maxHeap.size() > minHeap.size() ? maxHeap.peek() * 1.0 : minHeap.peek() * 1.0;
     }
 }
diff --git a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
new file mode 100644
index 000000000000..96cdc77e92a2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
@@ -0,0 +1,161 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.apache.commons.lang3.tuple.Pair;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test case for Two sum Problem.
+ * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
+ */
+
+public class MedianOfRunningArrayTest {
+    private static final String EXCEPTION_MESSAGE = "Enter at least 1 element, Median of empty list is not defined!";
+
+    @Test
+    public void testWhenInvalidInoutProvidedShouldThrowException() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> stream.median());
+        assertEquals(exception.getMessage(), EXCEPTION_MESSAGE);
+    }
+
+    @Test
+    public void testWithNegativeValues() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(-1);
+        assertEquals(-1, stream.median());
+        stream.insert(-2);
+        assertEquals(-1.5, stream.median());
+        stream.insert(-3);
+        assertEquals(-2, stream.median());
+    }
+
+    @Test
+    public void testWithSingleValues() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(-1);
+        assertEquals(-1, stream.median());
+    }
+
+    @Test
+    public void testWithRandomValues() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(10);
+        assertEquals(10.0, stream.median());
+
+        stream.insert(5);
+        assertEquals(7.5, stream.median());
+
+        stream.insert(20);
+        assertEquals(10.0, stream.median());
+
+        stream.insert(15);
+        assertEquals(12.5, stream.median());
+
+        stream.insert(25);
+        assertEquals(15.0, stream.median());
+
+        stream.insert(30);
+        assertEquals(17.5, stream.median());
+
+        stream.insert(35);
+        assertEquals(20.0, stream.median());
+
+        stream.insert(1);
+        assertEquals(17.5, stream.median());
+    }
+
+    @Test
+    public void testWithNegativeAndPositiveValues() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(-1);
+        assertEquals(-1, stream.median());
+        stream.insert(2);
+        assertEquals(0.5, stream.median());
+        stream.insert(-3);
+        assertEquals(-1, stream.median());
+    }
+
+    @Test
+    public void testWithDuplicateValues() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(-1);
+        assertEquals(-1, stream.median());
+        stream.insert(-1);
+        assertEquals(-1, stream.median());
+        stream.insert(-1);
+        assertEquals(-1, stream.median());
+    }
+
+    @Test
+    public void testWithDuplicateValuesB() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(10);
+        stream.insert(20);
+        stream.insert(10);
+        stream.insert(10);
+        stream.insert(20);
+        stream.insert(0);
+        stream.insert(50);
+        assertEquals(10, stream.median());
+    }
+
+    @Test
+    public void testWithLargeValues() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(1000000);
+        assertEquals(1000000, stream.median());
+        stream.insert(12000);
+        assertEquals(506000, stream.median());
+        stream.insert(15000000);
+        assertEquals(1000000, stream.median());
+        stream.insert(2300000);
+        assertEquals(1650000.00, stream.median());
+    }
+
+    @Test
+    public void testWithLargeCountOfValues() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        for (int i = 1; i <= 1000; i++) stream.insert(i);
+        assertEquals(500.5, stream.median());
+    }
+
+    @Test
+    public void testWithThreeValuesInDescendingOrder() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(30);
+        stream.insert(20);
+        stream.insert(10);
+        assertEquals(20.0, stream.median());
+    }
+
+    @Test
+    public void testWithThreeValuesInOrder() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(10);
+        stream.insert(20);
+        stream.insert(30);
+        assertEquals(20.0, stream.median());
+    }
+
+    @Test
+    public void testWithThreeValuesNotInOrderA() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(30);
+        stream.insert(10);
+        stream.insert(20);
+        assertEquals(20.0, stream.median());
+    }
+
+    @Test
+    public void testWithThreeValuesNotInOrderB() {
+        MedianOfRunningArray stream = new MedianOfRunningArray();
+        stream.insert(20);
+        stream.insert(10);
+        stream.insert(30);
+        assertEquals(20.0, stream.median());
+    }
+}

From 8803b1ead59716617b221a8ef92a90cc0ec067c2 Mon Sep 17 00:00:00 2001
From: Manan Solanki <76104205+Manan-09@users.noreply.github.com>
Date: Sat, 23 Sep 2023 13:56:14 +0530
Subject: [PATCH 0004/1338] #4387 Enhance Minimum sum partition problem
 implementation (#4394)

* Enhance Minimum sum partition problem implementation

* Linter resolved

* Linter resolved

* Code review comments

* Code review comments

* Add validation for non-negative numbers

* Linter resolved

* style: fix formiatting

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../MinimumSumPartition.java                  | 106 ++++++------------
 .../MinimumSumPartitionTest.java              |  44 ++++++++
 2 files changed, 81 insertions(+), 69 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MinimumSumPartition.java b/src/main/java/com/thealgorithms/dynamicprogramming/MinimumSumPartition.java
index c15c0186fc62..52308c23cf1c 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/MinimumSumPartition.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MinimumSumPartition.java
@@ -1,89 +1,57 @@
 package com.thealgorithms.dynamicprogramming;
 
-// Partition a set into two subsets such that the difference of subset sums is minimum
+import java.util.Arrays;
 
 /*
-Input:  arr[] = {1, 6, 11, 5}
-Output: 1
+Given an array of non-negative integers , partition the array in two subset that
+difference in sum of elements for both subset minimum.
+Return the minimum difference in sum of these subsets you can achieve.
+
+Input:  array[] = {1, 6, 11, 4}
+Output: 0
 Explanation:
-Subset1 = {1, 5, 6}, sum of Subset1 = 12
+Subset1 = {1, 4, 6}, sum of Subset1 = 11
 Subset2 = {11}, sum of Subset2 = 11
 
-Input:  arr[] = {36, 7, 46, 40}
+Input:  array[] = {36, 7, 46, 40}
 Output: 23
 Explanation:
 Subset1 = {7, 46} ;  sum of Subset1 = 53
 Subset2 = {36, 40} ; sum of Subset2  = 76
  */
-public class MinimumSumPartition {
-
-    public static int subSet(int[] arr) {
-        int n = arr.length;
-        int sum = getSum(arr);
-        boolean[][] dp = new boolean[n + 1][sum + 1];
-        for (int i = 0; i <= n; i++) {
-            dp[i][0] = true;
-        }
-        for (int j = 0; j <= sum; j++) {
-            dp[0][j] = false;
-        }
-
-        // fill dp array
-        for (int i = 1; i <= n; i++) {
-            for (int j = 1; j <= sum; j++) {
-                if (arr[i - 1] < j) {
-                    dp[i][j] = dp[i - 1][j - arr[i - 1]] || dp[i - 1][j];
-                } else if (arr[i - 1] == j) {
-                    dp[i][j] = true;
-                } else {
-                    dp[i][j] = dp[i - 1][j];
-                }
-            }
-        }
-
-        // fill the index array
-        int[] index = new int[sum];
-        int p = 0;
-        for (int i = 0; i <= sum / 2; i++) {
-            if (dp[n][i]) {
-                index[p++] = i;
-            }
-        }
-
-        return getMin(index, sum);
+public final class MinimumSumPartition {
+    private MinimumSumPartition() {
     }
 
-    /**
-     * Calculate sum of array elements
-     *
-     * @param arr the array
-     * @return sum of given array
-     */
-    public static int getSum(int[] arr) {
-        int sum = 0;
-        for (int temp : arr) {
-            sum += temp;
+    private static void throwIfInvalidInput(final int[] array) {
+        if (Arrays.stream(array).anyMatch(a -> a < 0)) {
+            throw new IllegalArgumentException("Input array should not contain negative number(s).");
         }
-        return sum;
     }
 
-    public static int getMin(int[] arr, int sum) {
-        if (arr.length == 0) {
-            return 0;
-        }
-        int min = Integer.MAX_VALUE;
-        for (int temp : arr) {
-            min = Math.min(min, sum - 2 * temp);
-        }
-        return min;
-    }
+    public static int minimumSumPartition(final int[] array) {
+        throwIfInvalidInput(array);
+        int sum = Arrays.stream(array).sum();
+        boolean[] dp = new boolean[sum / 2 + 1];
+        dp[0] = true; // Base case , don't select any element from array
 
-    /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        assert subSet(new int[] {1, 6, 11, 5}) == 1;
-        assert subSet(new int[] {36, 7, 46, 40}) == 23;
-        assert subSet(new int[] {1, 2, 3, 9}) == 3;
+        // Find the closest sum of subset array that we can achieve which is closest to half of sum of full array
+        int closestPartitionSum = 0;
+
+        for (int i = 0; i < array.length; i++) {
+            for (int j = sum / 2; j > 0; j--) {
+                if (array[i] <= j) {
+                    dp[j] = dp[j] || dp[j - array[i]];
+                }
+                if (dp[j]) {
+                    closestPartitionSum = Math.max(closestPartitionSum, j);
+                }
+            }
+        }
+        /*
+        Difference in sum = Big partition sum  - Small partition sum
+                          = ( Total sum - Small partition sum) - Small partition sum
+         */
+        return sum - (2 * closestPartitionSum);
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java
new file mode 100644
index 000000000000..1f14320244ea
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class MinimumSumPartitionTest {
+    @Test
+    public void testMinimumSumPartitionWithEvenSum() {
+        int[] array = {1, 6, 11, 4};
+        assertEquals(0, MinimumSumPartition.minimumSumPartition(array));
+    }
+
+    @Test
+    public void testMinimumSumPartitionWithOddSum() {
+        int[] array = {36, 7, 46, 40};
+        assertEquals(23, MinimumSumPartition.minimumSumPartition(array));
+    }
+
+    @Test
+    public void testMinimumSumPartitionWithSingleElement() {
+        int[] array = {7};
+        assertEquals(7, MinimumSumPartition.minimumSumPartition(array));
+    }
+
+    @Test
+    public void testMinimumSumPartitionWithLargeNumbers() {
+        int[] array = {100, 200, 300, 400, 500};
+        assertEquals(100, MinimumSumPartition.minimumSumPartition(array));
+    }
+
+    @Test
+    public void testMinimumSumPartitionWithEmptyArray() {
+        int[] array = {};
+        assertEquals(0, MinimumSumPartition.minimumSumPartition(array));
+    }
+
+    @Test
+    public void testMinimumSumPartitionThrowsForNegativeArray() {
+        int[] array = {4, 1, -6, 7};
+        assertThrows(IllegalArgumentException.class, () -> { MinimumSumPartition.minimumSumPartition(array); });
+    }
+}

From d3a32135dc9230125599c38d56849228f99a3b11 Mon Sep 17 00:00:00 2001
From: Ansh Shah <60037118+govardhanshah456@users.noreply.github.com>
Date: Sun, 24 Sep 2023 11:20:43 +0530
Subject: [PATCH 0005/1338] Make `MedianOfRunningArray` Generic (#4392)

---
 .../misc/MedianOfRunningArray.java            |  24 ++--
 .../misc/MedianOfRunningArrayByte.java        |   8 ++
 .../misc/MedianOfRunningArrayDouble.java      |   8 ++
 .../misc/MedianOfRunningArrayFloat.java       |   8 ++
 .../misc/MedianOfRunningArrayInteger.java     |   8 ++
 .../misc/MedianOfRunningArrayLong.java        |   8 ++
 .../misc/MedianOfRunningArrayTest.java        | 104 ++++++++++++------
 7 files changed, 124 insertions(+), 44 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/misc/MedianOfRunningArrayByte.java
 create mode 100644 src/main/java/com/thealgorithms/misc/MedianOfRunningArrayDouble.java
 create mode 100644 src/main/java/com/thealgorithms/misc/MedianOfRunningArrayFloat.java
 create mode 100644 src/main/java/com/thealgorithms/misc/MedianOfRunningArrayInteger.java
 create mode 100644 src/main/java/com/thealgorithms/misc/MedianOfRunningArrayLong.java

diff --git a/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java b/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
index 61fbfa82003f..62013ee31183 100644
--- a/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
+++ b/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
@@ -6,10 +6,10 @@
 /**
  * @author shrutisheoran
  */
-public class MedianOfRunningArray {
+public abstract class MedianOfRunningArray<T extends Number & Comparable<T>> {
 
-    private PriorityQueue<Integer> maxHeap;
-    private PriorityQueue<Integer> minHeap;
+    private PriorityQueue<T> maxHeap;
+    private PriorityQueue<T> minHeap;
 
     // Constructor
     public MedianOfRunningArray() {
@@ -21,8 +21,8 @@ public MedianOfRunningArray() {
       Inserting lower half of array to max Heap
       and upper half to min heap
      */
-    public void insert(Integer e) {
-        if (!minHeap.isEmpty() && e < minHeap.peek()) {
+    public void insert(final T e) {
+        if (!minHeap.isEmpty() && e.compareTo(minHeap.peek()) < 0) {
             maxHeap.offer(e);
             if (maxHeap.size() > minHeap.size() + 1) {
                 minHeap.offer(maxHeap.poll());
@@ -38,14 +38,16 @@ public void insert(Integer e) {
     /*
       Returns median at any given point
      */
-    public double median() {
+    public T median() {
         if (maxHeap.isEmpty() && minHeap.isEmpty()) {
             throw new IllegalArgumentException("Enter at least 1 element, Median of empty list is not defined!");
+        } else if (maxHeap.size() == minHeap.size()) {
+            T maxHeapTop = maxHeap.peek();
+            T minHeapTop = minHeap.peek();
+            return calculateAverage(maxHeapTop, minHeapTop);
         }
-
-        if (maxHeap.size() == minHeap.size()) {
-            return (maxHeap.peek() + minHeap.peek()) / 2.0;
-        }
-        return maxHeap.size() > minHeap.size() ? maxHeap.peek() * 1.0 : minHeap.peek() * 1.0;
+        return maxHeap.size() > minHeap.size() ? maxHeap.peek() : minHeap.peek();
     }
+
+    public abstract T calculateAverage(T a, T b);
 }
diff --git a/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayByte.java b/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayByte.java
new file mode 100644
index 000000000000..668f651e7251
--- /dev/null
+++ b/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayByte.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.misc;
+
+public final class MedianOfRunningArrayByte extends MedianOfRunningArray<Byte> {
+    @Override
+    public Byte calculateAverage(final Byte a, final Byte b) {
+        return (byte) ((a + b) / 2);
+    }
+}
diff --git a/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayDouble.java b/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayDouble.java
new file mode 100644
index 000000000000..9d743de51643
--- /dev/null
+++ b/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayDouble.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.misc;
+
+public final class MedianOfRunningArrayDouble extends MedianOfRunningArray<Double> {
+    @Override
+    public Double calculateAverage(final Double a, final Double b) {
+        return (a + b) / 2.0d;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayFloat.java b/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayFloat.java
new file mode 100644
index 000000000000..a667abf6121b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayFloat.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.misc;
+
+public final class MedianOfRunningArrayFloat extends MedianOfRunningArray<Float> {
+    @Override
+    public Float calculateAverage(final Float a, final Float b) {
+        return (a + b) / 2.0f;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayInteger.java b/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayInteger.java
new file mode 100644
index 000000000000..7154ba073136
--- /dev/null
+++ b/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayInteger.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.misc;
+
+public final class MedianOfRunningArrayInteger extends MedianOfRunningArray<Integer> {
+    @Override
+    public Integer calculateAverage(final Integer a, final Integer b) {
+        return (a + b) / 2;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayLong.java b/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayLong.java
new file mode 100644
index 000000000000..1f138c6313fb
--- /dev/null
+++ b/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayLong.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.misc;
+
+public final class MedianOfRunningArrayLong extends MedianOfRunningArray<Long> {
+    @Override
+    public Long calculateAverage(final Long a, final Long b) {
+        return (a + b) / 2L;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
index 96cdc77e92a2..90910d511ca0 100644
--- a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
+++ b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
@@ -1,15 +1,13 @@
 package com.thealgorithms.misc;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import org.apache.commons.lang3.tuple.Pair;
 import org.junit.jupiter.api.Test;
 
 /**
- * Test case for Two sum Problem.
- * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
+ * Test case for Median Of Running Array Problem.
+ * @author Ansh Shah (https://github.com/govardhanshah456)
  */
 
 public class MedianOfRunningArrayTest {
@@ -17,71 +15,71 @@ public class MedianOfRunningArrayTest {
 
     @Test
     public void testWhenInvalidInoutProvidedShouldThrowException() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> stream.median());
         assertEquals(exception.getMessage(), EXCEPTION_MESSAGE);
     }
 
     @Test
     public void testWithNegativeValues() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(-1);
         assertEquals(-1, stream.median());
         stream.insert(-2);
-        assertEquals(-1.5, stream.median());
+        assertEquals(-1, stream.median());
         stream.insert(-3);
         assertEquals(-2, stream.median());
     }
 
     @Test
     public void testWithSingleValues() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(-1);
         assertEquals(-1, stream.median());
     }
 
     @Test
     public void testWithRandomValues() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(10);
-        assertEquals(10.0, stream.median());
+        assertEquals(10, stream.median());
 
         stream.insert(5);
-        assertEquals(7.5, stream.median());
+        assertEquals(7, stream.median());
 
         stream.insert(20);
-        assertEquals(10.0, stream.median());
+        assertEquals(10, stream.median());
 
         stream.insert(15);
-        assertEquals(12.5, stream.median());
+        assertEquals(12, stream.median());
 
         stream.insert(25);
-        assertEquals(15.0, stream.median());
+        assertEquals(15, stream.median());
 
         stream.insert(30);
-        assertEquals(17.5, stream.median());
+        assertEquals(17, stream.median());
 
         stream.insert(35);
-        assertEquals(20.0, stream.median());
+        assertEquals(20, stream.median());
 
         stream.insert(1);
-        assertEquals(17.5, stream.median());
+        assertEquals(17, stream.median());
     }
 
     @Test
     public void testWithNegativeAndPositiveValues() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(-1);
         assertEquals(-1, stream.median());
         stream.insert(2);
-        assertEquals(0.5, stream.median());
+        assertEquals(0, stream.median());
         stream.insert(-3);
         assertEquals(-1, stream.median());
     }
 
     @Test
     public void testWithDuplicateValues() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(-1);
         assertEquals(-1, stream.median());
         stream.insert(-1);
@@ -92,7 +90,7 @@ public void testWithDuplicateValues() {
 
     @Test
     public void testWithDuplicateValuesB() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(10);
         stream.insert(20);
         stream.insert(10);
@@ -105,7 +103,7 @@ public void testWithDuplicateValuesB() {
 
     @Test
     public void testWithLargeValues() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(1000000);
         assertEquals(1000000, stream.median());
         stream.insert(12000);
@@ -113,49 +111,89 @@ public void testWithLargeValues() {
         stream.insert(15000000);
         assertEquals(1000000, stream.median());
         stream.insert(2300000);
-        assertEquals(1650000.00, stream.median());
+        assertEquals(1650000, stream.median());
     }
 
     @Test
     public void testWithLargeCountOfValues() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         for (int i = 1; i <= 1000; i++) stream.insert(i);
-        assertEquals(500.5, stream.median());
+        assertEquals(500, stream.median());
     }
 
     @Test
     public void testWithThreeValuesInDescendingOrder() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(30);
         stream.insert(20);
         stream.insert(10);
-        assertEquals(20.0, stream.median());
+        assertEquals(20, stream.median());
     }
 
     @Test
     public void testWithThreeValuesInOrder() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(10);
         stream.insert(20);
         stream.insert(30);
-        assertEquals(20.0, stream.median());
+        assertEquals(20, stream.median());
     }
 
     @Test
     public void testWithThreeValuesNotInOrderA() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(30);
         stream.insert(10);
         stream.insert(20);
-        assertEquals(20.0, stream.median());
+        assertEquals(20, stream.median());
     }
 
     @Test
     public void testWithThreeValuesNotInOrderB() {
-        MedianOfRunningArray stream = new MedianOfRunningArray();
+        var stream = new MedianOfRunningArrayInteger();
         stream.insert(20);
         stream.insert(10);
         stream.insert(30);
-        assertEquals(20.0, stream.median());
+        assertEquals(20, stream.median());
+    }
+
+    @Test
+    public void testWithFloatValues() {
+        var stream = new MedianOfRunningArrayFloat();
+        stream.insert(20.0f);
+        assertEquals(20.0f, stream.median());
+        stream.insert(10.5f);
+        assertEquals(15.25f, stream.median());
+        stream.insert(30.0f);
+        assertEquals(20.0f, stream.median());
+    }
+
+    @Test
+    public void testWithByteValues() {
+        var stream = new MedianOfRunningArrayByte();
+        stream.insert((byte) 120);
+        assertEquals((byte) 120, stream.median());
+        stream.insert((byte) -120);
+        assertEquals((byte) 0, stream.median());
+        stream.insert((byte) 127);
+        assertEquals((byte) 120, stream.median());
+    }
+
+    @Test
+    public void testWithLongValues() {
+        var stream = new MedianOfRunningArrayLong();
+        stream.insert(120000000L);
+        assertEquals(120000000L, stream.median());
+        stream.insert(92233720368547757L);
+        assertEquals(46116860244273878L, stream.median());
+    }
+
+    @Test
+    public void testWithDoubleValues() {
+        var stream = new MedianOfRunningArrayDouble();
+        stream.insert(12345.67891);
+        assertEquals(12345.67891, stream.median());
+        stream.insert(23456789.98);
+        assertEquals(Double.valueOf(11734567.83), stream.median(), .01);
     }
 }

From c1476d796c54e4f9ee47f91895a7d830461f9a68 Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Sun, 24 Sep 2023 08:26:05 +0200
Subject: [PATCH 0006/1338] Make FindMin more efficient (#4389)

---
 src/main/java/com/thealgorithms/maths/FindMin.java | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/FindMin.java b/src/main/java/com/thealgorithms/maths/FindMin.java
index 7764c1c049b4..cab03628a75a 100644
--- a/src/main/java/com/thealgorithms/maths/FindMin.java
+++ b/src/main/java/com/thealgorithms/maths/FindMin.java
@@ -34,10 +34,10 @@ public static int findMin(int[] array) {
         if (array.length == 0) {
             throw new IllegalArgumentException("array must be non-empty.");
         }
-        int min = Integer.MAX_VALUE;
-        for (final var value : array) {
-            if (value < min) {
-                min = value;
+        int min = array[0];
+        for (int i = 1; i < array.length; i++) {
+            if (array[i] < min) {
+                min = array[i];
             }
         }
         return min;

From ad4be217d43fdaa38c994d7397ba5e732de26096 Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Sun, 24 Sep 2023 09:11:36 +0200
Subject: [PATCH 0007/1338] Update FindMax.java (#4396)

---
 src/main/java/com/thealgorithms/maths/FindMax.java | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/FindMax.java b/src/main/java/com/thealgorithms/maths/FindMax.java
index 559424fe15df..8587e3abb198 100644
--- a/src/main/java/com/thealgorithms/maths/FindMax.java
+++ b/src/main/java/com/thealgorithms/maths/FindMax.java
@@ -34,10 +34,10 @@ public static int findMax(int[] array) {
         if (array.length == 0) {
             throw new IllegalArgumentException("array must be non-empty.");
         }
-        int max = Integer.MIN_VALUE;
-        for (final var value : array) {
-            if (value > max) {
-                max = value;
+        int max = array[0];
+        for (int i = 1; i < array.length; i++) {
+            if (array[i] > max) {
+                max = array[i];
             }
         }
         return max;

From fa77b50ef9edb90949db77de76116c1a3ede10a1 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 24 Sep 2023 10:25:19 +0200
Subject: [PATCH 0008/1338] style: make `FindMax` a proper utilty class (#4398)

---
 .../java/com/thealgorithms/maths/FindMax.java | 25 +++----------------
 1 file changed, 3 insertions(+), 22 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/FindMax.java b/src/main/java/com/thealgorithms/maths/FindMax.java
index 8587e3abb198..76bde5ff600f 100644
--- a/src/main/java/com/thealgorithms/maths/FindMax.java
+++ b/src/main/java/com/thealgorithms/maths/FindMax.java
@@ -1,26 +1,7 @@
 package com.thealgorithms.maths;
 
-import java.util.Arrays;
-import java.util.Random;
-
-public class FindMax {
-
-    /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        Random random = new Random();
-
-        /* random size */
-        int size = random.nextInt(100) + 1;
-        int[] array = new int[size];
-
-        /* init array with random numbers */
-        for (int i = 0; i < size; i++) {
-            array[i] = random.nextInt() % 100;
-        }
-
-        assert Arrays.stream(array).max().getAsInt() == findMax(array);
+public final class FindMax {
+    private FindMax() {
     }
 
     /**
@@ -30,7 +11,7 @@ public static void main(String[] args) {
      * @exception IllegalArgumentException input array is empty
      * @return the maximum value stored in the input array
      */
-    public static int findMax(int[] array) {
+    public static int findMax(final int[] array) {
         if (array.length == 0) {
             throw new IllegalArgumentException("array must be non-empty.");
         }

From d6024f9cd49e3dc33576cb949ba379e62ad42528 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 24 Sep 2023 12:25:28 +0200
Subject: [PATCH 0009/1338] Make `FindMin` a proper utilty class (#4397)

---
 .../java/com/thealgorithms/maths/FindMin.java | 25 +++----------------
 1 file changed, 3 insertions(+), 22 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/FindMin.java b/src/main/java/com/thealgorithms/maths/FindMin.java
index cab03628a75a..10a03c801098 100644
--- a/src/main/java/com/thealgorithms/maths/FindMin.java
+++ b/src/main/java/com/thealgorithms/maths/FindMin.java
@@ -1,26 +1,7 @@
 package com.thealgorithms.maths;
 
-import java.util.Arrays;
-import java.util.Random;
-
-public class FindMin {
-
-    /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        Random random = new Random();
-
-        /* random size */
-        int size = random.nextInt(100) + 1;
-        int[] array = new int[size];
-
-        /* init array with random numbers */
-        for (int i = 0; i < size; i++) {
-            array[i] = random.nextInt() % 100;
-        }
-
-        assert Arrays.stream(array).min().getAsInt() == findMin(array);
+public final class FindMin {
+    private FindMin() {
     }
 
     /**
@@ -30,7 +11,7 @@ public static void main(String[] args) {
      * @exception IllegalArgumentException input array is empty
      * @return the mimum value stored in the input array
      */
-    public static int findMin(int[] array) {
+    public static int findMin(final int[] array) {
         if (array.length == 0) {
             throw new IllegalArgumentException("array must be non-empty.");
         }

From 9d8a0f36cfa45e96589532b5487b654d4cbb278d Mon Sep 17 00:00:00 2001
From: Manan Solanki <76104205+Manan-09@users.noreply.github.com>
Date: Mon, 25 Sep 2023 19:55:16 +0530
Subject: [PATCH 0010/1338] Optimize MinimumPathSum (#4400)

---
 .../dynamicprogramming/MinimumPathSum.java    | 62 +++++++++----------
 .../MinimumPathSumTest.java                   |  8 ++-
 2 files changed, 35 insertions(+), 35 deletions(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MinimumPathSum.java b/src/main/java/com/thealgorithms/dynamicprogramming/MinimumPathSum.java
index cd1f25a46664..98773de92f6b 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/MinimumPathSum.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MinimumPathSum.java
@@ -12,9 +12,8 @@
 (m)
 Find the path where its sum is the smallest.
 
-All numbers given are positive.
 The Time Complexity of your algorithm should be smaller than or equal to O(mn).
-The Space Complexity of your algorithm should be smaller than or equal to O(mn).
+The Space Complexity of your algorithm should be smaller than or equal to O(n).
 You can only move from the top left corner to the down right corner.
 You can only move one step down or right.
 
@@ -25,46 +24,41 @@ The Space Complexity of your algorithm should be smaller than or equal to O(mn).
 
 For more information see https://www.geeksforgeeks.org/maximum-path-sum-matrix/
  */
-public class MinimumPathSum {
+public final class MinimumPathSum {
 
-    public void testRegular() {
-        int[][] grid = {{1, 3, 1}, {1, 5, 1}, {4, 2, 1}};
-        System.out.println(minimumPathSum(grid));
+    private MinimumPathSum() {
     }
 
-    public void testLessColumns() {
-        int[][] grid = {{1, 2}, {5, 6}, {1, 1}};
-        System.out.println(minimumPathSum(grid));
-    }
-
-    public void testLessRows() {
-        int[][] grid = {{2, 3, 3}, {7, 2, 1}};
-        System.out.println(minimumPathSum(grid));
-    }
+    public static int minimumPathSum(final int[][] grid) {
+        int numRows = grid.length;
+        int numCols = grid[0].length;
 
-    public void testOneRowOneColumn() {
-        int[][] grid = {{2}};
-        System.out.println(minimumPathSum(grid));
-    }
-
-    public static int minimumPathSum(int[][] grid) {
-        int m = grid.length, n = grid[0].length;
-        if (n == 0) {
+        if (numCols == 0) {
             return 0;
         }
-        int[][] dp = new int[m][n];
-        dp[0][0] = grid[0][0];
-        for (int i = 0; i < n - 1; i++) {
-            dp[0][i + 1] = dp[0][i] + grid[0][i + 1];
-        }
-        for (int i = 0; i < m - 1; i++) {
-            dp[i + 1][0] = dp[i][0] + grid[i + 1][0];
+
+        int[] dp = new int[numCols];
+
+        // Initialize the first element of the dp array
+        dp[0] = grid[0][0];
+
+        // Calculate the minimum path sums for the first row
+        for (int col = 1; col < numCols; col++) {
+            dp[col] = dp[col - 1] + grid[0][col];
         }
-        for (int i = 1; i < m; i++) {
-            for (int j = 1; j < n; j++) {
-                dp[i][j] = Math.min(dp[i - 1][j], dp[i][j - 1]) + grid[i][j];
+
+        // Calculate the minimum path sums for the remaining rows
+        for (int row = 1; row < numRows; row++) {
+            // Update the minimum path sum for the first column
+            dp[0] += grid[row][0];
+
+            for (int col = 1; col < numCols; col++) {
+                // Choose the minimum path sum from the left or above
+                dp[col] = Math.min(dp[col - 1], dp[col]) + grid[row][col];
             }
         }
-        return dp[m - 1][n - 1];
+
+        // Return the minimum path sum for the last cell in the grid
+        return dp[numCols - 1];
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java
index 25e2d8372b49..5c722c3c0036 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.dynamicprogramming;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
@@ -41,4 +41,10 @@ public void testMinimumPathSumWithDiffRowAndColumnGrid() {
         int[][] grid = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
         assertEquals(30, MinimumPathSum.minimumPathSum(grid));
     }
+
+    @Test
+    public void testMinimumPathSumWithNegativeNumberGrid() {
+        int[][] grid = {{1, 3, 1}, {3, 4, 1}, {4, -3, 1}};
+        assertEquals(6, MinimumPathSum.minimumPathSum(grid));
+    }
 }

From 01157f299c20011cf6227039909b9ecc3a99341c Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Mon, 25 Sep 2023 20:38:54 +0200
Subject: [PATCH 0011/1338] Add negative FindMinTest (#4388)

---
 .../com/thealgorithms/maths/FindMinTest.java  | 28 ++++++++-----------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/src/test/java/com/thealgorithms/maths/FindMinTest.java b/src/test/java/com/thealgorithms/maths/FindMinTest.java
index 7599b9029bf1..7884b4b79281 100644
--- a/src/test/java/com/thealgorithms/maths/FindMinTest.java
+++ b/src/test/java/com/thealgorithms/maths/FindMinTest.java
@@ -1,30 +1,24 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class FindMinTest {
 
-    @Test
-    public void testFindMinValue() {
-        assertEquals(1, FindMin.findMin(new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
-    }
-
-    @Test
-    public void test1() {
-        assertEquals(1, FindMin.findMin(new int[] {1, 3, 5, 7, 9}));
+    @ParameterizedTest
+    @MethodSource("provideStringsForIsBlank")
+    void numberTests(int expected, int[] input) {
+        Assertions.assertEquals(expected, FindMin.findMin(input));
     }
 
-    @Test
-    public void test2() {
-        assertEquals(0, FindMin.findMin(new int[] {0, 192, 384, 576}));
-    }
-
-    @Test
-    public void test3() {
-        assertEquals(0, FindMin.findMin(new int[] {10, 10, 0, 10}));
+    private static Stream<Arguments> provideStringsForIsBlank() {
+        return Stream.of(Arguments.of(1, new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}), Arguments.of(5, new int[] {5, 5, 5, 5, 5}), Arguments.of(0, new int[] {0, 192, 384, 576}), Arguments.of(-1, new int[] {-1, 2, 5, 10}), Arguments.of(-10, new int[] {-10, -9, -8, -7, -6, -5, -4, -3, -2, -1}));
     }
 
     @Test

From cada67b1eb58558b08049b84ee93a15de7867e4b Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Mon, 25 Sep 2023 21:10:04 +0200
Subject: [PATCH 0012/1338] Remove array len + Math.max (#4401)

---
 .../java/com/thealgorithms/maths/FindMaxRecursion.java   | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java b/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java
index c38da196f46e..f6acafd2684c 100644
--- a/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java
+++ b/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java
@@ -17,7 +17,7 @@ public static void main(String[] args) {
             array[i] = rand.nextInt() % 100;
         }
 
-        assert max(array, array.length) == Arrays.stream(array).max().getAsInt();
+        assert max(array) == Arrays.stream(array).max().getAsInt();
         assert max(array, 0, array.length - 1) == Arrays.stream(array).max().getAsInt();
     }
 
@@ -39,17 +39,16 @@ public static int max(int[] array, int low, int high) {
         int leftMax = max(array, low, mid); // get max in [low, mid]
         int rightMax = max(array, mid + 1, high); // get max in [mid+1, high]
 
-        return Math.max(leftMax, rightMax);
+        return leftMax < rightMax ? rightMax : leftMax;
     }
 
     /**
      * Get max of array using recursion algorithm
      *
      * @param array contains elements
-     * @param len length of given array
      * @return max value of {@code array}
      */
-    public static int max(int[] array, int len) {
-        return len == 1 ? array[0] : Math.max(max(array, len - 1), array[len - 1]);
+    public static int max(int[] array) {
+        return array.length == 1 ? array[0] : max(array, 0, array.length);
     }
 }

From 02bac7e3d4f152a2369dca61cc1b2a1664bbcf24 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 26 Sep 2023 07:41:27 +0200
Subject: [PATCH 0013/1338] Add test case with minimum not at index 0 (#4403)

---
 src/test/java/com/thealgorithms/maths/FindMinTest.java | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/test/java/com/thealgorithms/maths/FindMinTest.java b/src/test/java/com/thealgorithms/maths/FindMinTest.java
index 7884b4b79281..e713c0191ea1 100644
--- a/src/test/java/com/thealgorithms/maths/FindMinTest.java
+++ b/src/test/java/com/thealgorithms/maths/FindMinTest.java
@@ -12,13 +12,14 @@
 public class FindMinTest {
 
     @ParameterizedTest
-    @MethodSource("provideStringsForIsBlank")
+    @MethodSource("inputStream")
     void numberTests(int expected, int[] input) {
         Assertions.assertEquals(expected, FindMin.findMin(input));
     }
 
-    private static Stream<Arguments> provideStringsForIsBlank() {
-        return Stream.of(Arguments.of(1, new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}), Arguments.of(5, new int[] {5, 5, 5, 5, 5}), Arguments.of(0, new int[] {0, 192, 384, 576}), Arguments.of(-1, new int[] {-1, 2, 5, 10}), Arguments.of(-10, new int[] {-10, -9, -8, -7, -6, -5, -4, -3, -2, -1}));
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of(1, new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}), Arguments.of(5, new int[] {5, 5, 5, 5, 5}), Arguments.of(0, new int[] {0, 192, 384, 576}), Arguments.of(-1, new int[] {-1, 2, 5, 10}), Arguments.of(-10, new int[] {-10, -9, -8, -7, -6, -5, -4, -3, -2, -1}),
+            Arguments.of(-4, new int[] {4, -3, 8, 9, -4, -4, 10}));
     }
 
     @Test

From bf777fff8f075cccff32223cd2f5c085adb5b09e Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Tue, 26 Sep 2023 17:31:16 +0200
Subject: [PATCH 0014/1338] Remove array len + Math.min (#4405)

---
 .../java/com/thealgorithms/maths/FindMinRecursion.java    | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/FindMinRecursion.java b/src/main/java/com/thealgorithms/maths/FindMinRecursion.java
index 66400d23db3f..71d7795b7e47 100644
--- a/src/main/java/com/thealgorithms/maths/FindMinRecursion.java
+++ b/src/main/java/com/thealgorithms/maths/FindMinRecursion.java
@@ -21,7 +21,7 @@ public static void main(String[] args) {
         }
 
         assert min(array, 0, array.length - 1) == Arrays.stream(array).min().getAsInt();
-        assert min(array, array.length) == Arrays.stream(array).min().getAsInt();
+        assert min(array) == Arrays.stream(array).min().getAsInt();
     }
 
     /**
@@ -42,7 +42,7 @@ public static int min(int[] array, int low, int high) {
         int leftMin = min(array, low, mid); // get min in [low, mid]
         int rightMin = min(array, mid + 1, high); // get min in [mid+1, high]
 
-        return Math.min(leftMin, rightMin);
+        return leftMin > rightMin ? rightMin : leftMin;
     }
 
     /**
@@ -52,7 +52,7 @@ public static int min(int[] array, int low, int high) {
      * @param len length of given array
      * @return min value of {@code array}
      */
-    public static int min(int[] array, int len) {
-        return len == 1 ? array[0] : Math.min(min(array, len - 1), array[len - 1]);
+    public static int min(int[] array) {
+        return array.length == 1 ? array[0] : min(array, 0, array.length);
     }
 }

From 8583ca3b40ffb21d3005b7c354737e1ac9a3b39c Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Tue, 26 Sep 2023 21:36:56 +0200
Subject: [PATCH 0015/1338] Changing MaxFindTest (#4406)

* Changing MaxFindTest

* Update FindMaxTest.java

* Update FindMaxTest.java

* Update FindMaxTest.java

* Apply suggestions from code review

- add test case with unsorted array,
- test FindMax

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/maths/FindMaxTest.java  | 23 +++++++++----------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/src/test/java/com/thealgorithms/maths/FindMaxTest.java b/src/test/java/com/thealgorithms/maths/FindMaxTest.java
index 17f8d454c5ff..a863a2c8586b 100644
--- a/src/test/java/com/thealgorithms/maths/FindMaxTest.java
+++ b/src/test/java/com/thealgorithms/maths/FindMaxTest.java
@@ -1,25 +1,24 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class FindMaxTest {
 
-    @Test
-    public void testFindMax0() {
-        assertEquals(10, FindMax.findMax(new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
+    @ParameterizedTest
+    @MethodSource("inputStream")
+    void numberTests(int expected, int[] input) {
+        Assertions.assertEquals(expected, FindMax.findMax(input));
     }
 
-    @Test
-    public void testFindMax1() {
-        assertEquals(7, FindMax.findMax(new int[] {6, 3, 5, 1, 7, 4, 1}));
-    }
-
-    @Test
-    public void testFindMax2() {
-        assertEquals(10, FindMax.findMax(new int[] {10, 0}));
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of(10, new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}), Arguments.of(5, new int[] {5, 5, 5, 5, 5}), Arguments.of(0, new int[] {-1, 0}), Arguments.of(-1, new int[] {-10, -9, -8, -7, -6, -5, -4, -3, -2, -1}), Arguments.of(9, new int[] {3, -2, 3, 9, -4, -4, 8}));
     }
 
     @Test

From 1cf193c7f416cc7763261d9b5d02d451fa6473df Mon Sep 17 00:00:00 2001
From: Andrii Siriak <siryaka@gmail.com>
Date: Wed, 27 Sep 2023 10:10:03 +0300
Subject: [PATCH 0016/1338] Remove @siriak from CODEOWNERS

---
 .github/CODEOWNERS | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index c298ce670806..0706d623599a 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1 +1 @@
-* @siriak @yanglbme @debasishbsws @vil02 @BamaCharanChhandogi
+* @yanglbme @debasishbsws @vil02 @BamaCharanChhandogi

From 566c27a996f48a94916170c159ae735546b39c42 Mon Sep 17 00:00:00 2001
From: Janmesh Singh <68192323+janmeshjs@users.noreply.github.com>
Date: Wed, 27 Sep 2023 15:24:52 +0530
Subject: [PATCH 0017/1338] WildcardMatching Added (#4404)

* Added WildcardMatching DP

* Wildcard Matching update

* Updated WildcardMatching

* Added WildcardMatchingTests

* WildcardMatching update

* Clang-formatting done

* WildcardMatching_Clang-formatting done

* WildcardMatching
---
 .../dynamicprogramming/WildcardMatching.java  | 55 +++++++++++++++++++
 .../WildcardMatchingTest.java                 | 26 +++++++++
 2 files changed, 81 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java b/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java
new file mode 100644
index 000000000000..a938634cdfd2
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java
@@ -0,0 +1,55 @@
+/**
+ *
+ * Author: Janmesh Singh
+ * Github: https://github.com/janmeshjs
+
+ * Problem Statement: To determine if the pattern matches the text.
+ * The pattern can include two special wildcard characters:
+ *       ' ? ': Matches any single character.
+ *       ' * ': Matches zero or more of any character sequence.
+ *
+ * Use DP to return True if the pattern matches the entire text and False otherwise
+ *
+ */
+
+package com.thealgorithms.dynamicprogramming;
+
+public class WildcardMatching {
+
+    public static boolean isMatch(String text, String pattern) {
+        int m = text.length();
+        int n = pattern.length();
+
+        // Create a DP table to store intermediate results
+        boolean[][] dp = new boolean[m + 1][n + 1];
+
+        // Base case: an empty pattern matches an empty text
+        dp[0][0] = true;
+
+        // Handle patterns starting with '*'
+        for (int j = 1; j <= n; j++) {
+            if (pattern.charAt(j - 1) == '*') {
+                dp[0][j] = dp[0][j - 1];
+            }
+        }
+
+        // Fill the DP table
+        for (int i = 1; i <= m; i++) {
+            for (int j = 1; j <= n; j++) {
+                char textChar = text.charAt(i - 1);
+                char patternChar = pattern.charAt(j - 1);
+
+                if (patternChar == textChar || patternChar == '?') {
+                    dp[i][j] = dp[i - 1][j - 1];
+                } else if (patternChar == '*') {
+                    // '*' can match zero or more characters
+                    dp[i][j] = dp[i - 1][j] || dp[i][j - 1];
+                } else {
+                    dp[i][j] = false;
+                }
+            }
+        }
+        // The result is in the bottom-right cell of the DP table
+        return dp[m][n];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java
new file mode 100644
index 000000000000..8d91af663ec5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java
@@ -0,0 +1,26 @@
+package com.thealgorithms.dynamicprogramming;
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class WildcardMatchingTest {
+
+    @Test
+    public void testMatchingPattern() {
+        assertTrue(WildcardMatching.isMatch("aa", "a*"));
+        assertTrue(WildcardMatching.isMatch("adceb", "*a*b"));
+    }
+
+    @Test
+    public void testNonMatchingPattern() {
+        assertFalse(WildcardMatching.isMatch("cb", "?a"));
+        assertFalse(WildcardMatching.isMatch("acdcb", "a*c?b"));
+        assertFalse(WildcardMatching.isMatch("mississippi", "m*issi*iss?*i"));
+    }
+
+    @Test
+    public void testEmptyPattern() {
+        assertTrue(WildcardMatching.isMatch("", ""));
+        assertFalse(WildcardMatching.isMatch("abc", ""));
+    }
+}

From ea0eef128db5b3e5e1f9d58cb8a7e009cd508ead Mon Sep 17 00:00:00 2001
From: Arin <136636751+asapekia@users.noreply.github.com>
Date: Thu, 28 Sep 2023 22:00:41 +0530
Subject: [PATCH 0018/1338] corrected test file name (#4422)

---
 .../bitmanipulation/{SetBit.java => SetBitTest.java}              | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename src/test/java/com/thealgorithms/bitmanipulation/{SetBit.java => SetBitTest.java} (100%)

diff --git a/src/test/java/com/thealgorithms/bitmanipulation/SetBit.java b/src/test/java/com/thealgorithms/bitmanipulation/SetBitTest.java
similarity index 100%
rename from src/test/java/com/thealgorithms/bitmanipulation/SetBit.java
rename to src/test/java/com/thealgorithms/bitmanipulation/SetBitTest.java

From e5d33f35651e8b46ba2318dbd934dc3eeb81507b Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Sat, 30 Sep 2023 10:06:45 +0200
Subject: [PATCH 0019/1338] Add SingleBitOperations (#4415)

* SingleBitOperators

* Tests

* Update SingleBitOperatorTest.java

* Update SingleBitOperators.java

* Update SingleBitOperators.java

* Update SingleBitOperators.java

* Update SingleBitOperatorTest.java

* deliting files

* Update SingleBitOperators.java

* Update SingleBitOperatorTest.java

* Update SingleBitOperators.java

* Update SingleBitOperators.java

* Update SingleBitOperatorTest.java

* Update SingleBitOperatorTest.java

* Update and rename SingleBitOperators.java to SingleBitOperator.java

* Update SingleBitOperatorTest.java

* Update SingleBitOperator.java

* Update SingleBitOperator.java

* Update SingleBitOperator.java

* style: declare private default constructor

* fix: remove `SetBitTest.java`

* Update and rename SingleBitOperator.java to SingleBitOperations.java

* Update SingleBitOperatorTest.java

* Update SingleBitOperations.java

* Update and rename SingleBitOperatorTest.java to SingleBitOperationsTest.java

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../bitmanipulation/ClearBit.java             | 11 ------
 .../thealgorithms/bitmanipulation/SetBit.java | 10 ------
 .../bitmanipulation/SingleBitOperations.java  | 34 +++++++++++++++++++
 .../bitmanipulation/ClearBitTest.java         | 13 -------
 .../bitmanipulation/SetBitTest.java           | 13 -------
 .../SingleBitOperationsTest.java              | 32 +++++++++++++++++
 6 files changed, 66 insertions(+), 47 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/bitmanipulation/ClearBit.java
 delete mode 100644 src/main/java/com/thealgorithms/bitmanipulation/SetBit.java
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java
 delete mode 100644 src/test/java/com/thealgorithms/bitmanipulation/ClearBitTest.java
 delete mode 100644 src/test/java/com/thealgorithms/bitmanipulation/SetBitTest.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/ClearBit.java b/src/main/java/com/thealgorithms/bitmanipulation/ClearBit.java
deleted file mode 100644
index c863c46c53f7..000000000000
--- a/src/main/java/com/thealgorithms/bitmanipulation/ClearBit.java
+++ /dev/null
@@ -1,11 +0,0 @@
-package com.thealgorithms.bitmanipulation;
-/**
- * Clears the bit located at clear from num
- */
-
-public class ClearBit {
-    public static int clearBit(int num, int clear) {
-        int mask = ~(1 << clear);
-        return num & mask;
-    }
-}
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/SetBit.java b/src/main/java/com/thealgorithms/bitmanipulation/SetBit.java
deleted file mode 100644
index a48540013a5c..000000000000
--- a/src/main/java/com/thealgorithms/bitmanipulation/SetBit.java
+++ /dev/null
@@ -1,10 +0,0 @@
-package com.thealgorithms.bitmanipulation;
-/**
- * Sets a specific bit to 1
- */
-
-public class SetBit {
-    public static int setBit(int num, int bit) {
-        return num | (1 << bit);
-    }
-}
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java b/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java
new file mode 100644
index 000000000000..b41aeca19af6
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.bitmanipulation;
+
+/*
+ * Author: lukasb1b (https://github.com/lukasb1b)
+ */
+
+public final class SingleBitOperations {
+    private SingleBitOperations() {
+    }
+    /**
+     * Flip the bit at position 'bit' in 'num'
+     */
+    public static int flipBit(final int num, final int bit) {
+        return num ^ (1 << bit);
+    }
+    /**
+     * Set the bit at position 'bit' to 1 in the 'num' variable
+     */
+    public static int setBit(final int num, final int bit) {
+        return num | (1 << bit);
+    }
+    /**
+     * Clears the bit located at 'bit' from 'num'
+     */
+    public static int clearBit(final int num, final int bit) {
+        return num & ~(1 << bit);
+    }
+    /**
+     * Get the bit located at 'bit' from 'num'
+     */
+    public static int getBit(final int num, final int bit) {
+        return ((num >> bit) & 1);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/ClearBitTest.java b/src/test/java/com/thealgorithms/bitmanipulation/ClearBitTest.java
deleted file mode 100644
index 60f73e9dd73c..000000000000
--- a/src/test/java/com/thealgorithms/bitmanipulation/ClearBitTest.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package com.thealgorithms.bitmanipulation;
-
-import static org.junit.jupiter.api.Assertions.*;
-
-import org.junit.jupiter.api.Test;
-
-public class ClearBitTest {
-    @Test
-    public void clearBitTest() {
-        assertEquals(5, ClearBit.clearBit(7, 1));
-        assertEquals(5, ClearBit.clearBit(5, 1));
-    }
-}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/SetBitTest.java b/src/test/java/com/thealgorithms/bitmanipulation/SetBitTest.java
deleted file mode 100644
index b6d2514ed903..000000000000
--- a/src/test/java/com/thealgorithms/bitmanipulation/SetBitTest.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package com.thealgorithms.bitmanipulation;
-
-import static org.junit.jupiter.api.Assertions.*;
-
-import org.junit.jupiter.api.Test;
-
-class SetBitTest {
-    @Test
-    void testSetBit() {
-        assertEquals(5, SetBit.setBit(4, 0));
-        assertEquals(3, SetBit.setBit(3, 1));
-    }
-}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java
new file mode 100644
index 000000000000..a6bb76689ec8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java
@@ -0,0 +1,32 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class SingleBitOperationsTest {
+
+    @Test
+    public void flipBitTest() {
+        assertEquals(1, SingleBitOperations.flipBit(3, 1));
+        assertEquals(11, SingleBitOperations.flipBit(3, 3));
+    }
+
+    @Test
+    public void setBitTest() {
+        assertEquals(5, SingleBitOperations.setBit(4, 0));
+        assertEquals(4, SingleBitOperations.setBit(4, 2));
+    }
+
+    @Test
+    public void clearBitTest() {
+        assertEquals(5, SingleBitOperations.clearBit(7, 1));
+        assertEquals(5, SingleBitOperations.clearBit(5, 1));
+    }
+
+    @Test
+    public void getBitTest() {
+        assertEquals(0, SingleBitOperations.getBit(6, 0));
+        assertEquals(1, SingleBitOperations.getBit(7, 1));
+    }
+}

From ee2629c8ab5c5c27bd728fb02a92a67a74a76cbc Mon Sep 17 00:00:00 2001
From: ANKIT SAHA <85545712+Ankit-Saha08@users.noreply.github.com>
Date: Sun, 1 Oct 2023 16:28:13 +0530
Subject: [PATCH 0020/1338] Update Pangram.java using Java Collections (#4479)

* Update Pangram.java using Java Collections

A simple separate function isPangramOrNot(String s) has been created which implements the Pangram checking of a string using Java Collection Framework approach.

* Update Pangram.java using Java Collections

* Updated some linting errors in Pangram.java

* Update src/main/java/com/thealgorithms/strings/Pangram.java

Co-authored-by: Debasish Biswas <debasishbsws.dev@gmail.com>

* Updated Pangram.java

Method name updated to - isPangramUsingSet(String s)

* Updated the testcases PangramTest.java

Successfully updated the testcases in this same PR branch

---------

Co-authored-by: Debasish Biswas <debasishbsws.dev@gmail.com>
---
 .../com/thealgorithms/strings/Pangram.java     | 18 ++++++++++++++++++
 .../com/thealgorithms/strings/PangramTest.java |  5 +++++
 2 files changed, 23 insertions(+)

diff --git a/src/main/java/com/thealgorithms/strings/Pangram.java b/src/main/java/com/thealgorithms/strings/Pangram.java
index 4772ac826b5e..9d734579406c 100644
--- a/src/main/java/com/thealgorithms/strings/Pangram.java
+++ b/src/main/java/com/thealgorithms/strings/Pangram.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.strings;
 
+import java.util.HashSet;
+
 /**
  * Wikipedia: https://en.wikipedia.org/wiki/Pangram
  */
@@ -15,6 +17,22 @@ public static void main(String[] args) {
         assert !isPangram("\u0000/\\");
     }
 
+    /**
+     * Checks if a String is considered a Pangram
+     *
+     * @param s The String to check
+     * @return {@code true} if s is a Pangram, otherwise {@code false}
+     */
+    // alternative approach using Java Collection Framework
+    public static boolean isPangramUsingSet(String s) {
+        HashSet<Character> alpha = new HashSet<Character>();
+        s = s.trim().toLowerCase();
+        for (int i = 0; i < s.length(); i++)
+            if (s.charAt(i) != ' ') alpha.add(s.charAt(i));
+        if (alpha.size() == 26) return true;
+        return false;
+    }
+
     /**
      * Checks if a String is considered a Pangram
      *
diff --git a/src/test/java/com/thealgorithms/strings/PangramTest.java b/src/test/java/com/thealgorithms/strings/PangramTest.java
index 5d138a5ed7fb..7ad79b203b45 100644
--- a/src/test/java/com/thealgorithms/strings/PangramTest.java
+++ b/src/test/java/com/thealgorithms/strings/PangramTest.java
@@ -17,5 +17,10 @@ public void testPangram() {
         assertFalse(Pangram.isPangram2("The quick brown fox jumps over the azy dog")); // L is missing
         assertFalse(Pangram.isPangram2("+-1234 This string is not alphabetical"));
         assertFalse(Pangram.isPangram2("\u0000/\\ Invalid characters are alright too"));
+
+        assertTrue(Pangram.isPangramUsingSet("The quick brown fox jumps over the lazy dog"));
+        assertFalse(Pangram.isPangramUsingSet("The quick brown fox jumps over the azy dog")); // L is missing
+        assertFalse(Pangram.isPangramUsingSet("+-1234 This string is not alphabetical"));
+        assertFalse(Pangram.isPangramUsingSet("\u0000/\\ Invalid characters are alright too"));
     }
 }

From da687c11cb35d9c13c8d2681796b512e08f59f27 Mon Sep 17 00:00:00 2001
From: Pronay Debnath <pronayd4455@gmail.com>
Date: Sun, 1 Oct 2023 20:52:51 +0530
Subject: [PATCH 0021/1338] Added [FEATURE REQUEST] <Recursive Binary Search>
 #4457 (#4469)

* Create RecursiveBinarySearch.java

* Update RecursiveBinarySearch.java

* Update RecursiveBinarySearch.java

* Update RecursiveBinarySearch.java

* Update RecursiveBinarySearch.java

* Create ReverseArray.java

* Update RecursiveBinarySearch.java

* Update RecursiveBinarySearch.java

* Create RecursiveBinarySearchTest.java

* Update RecursiveBinarySearchTest.java

* Update RecursiveBinarySearchTest.java

* Delete src/main/java/com/thealgorithms/others/ReverseArray.java

* Update RecursiveBinarySearchTest.java

* Update RecursiveBinarySearchTest.java

* Create ReverseArray.java

* Delete src/main/java/com/thealgorithms/others/ReverseArray.java

* Update RecursiveBinarySearchTest.java

* Update RecursiveBinarySearch.java
---
 .../searches/RecursiveBinarySearch.java       | 74 +++++++++++++++++++
 .../searches/RecursiveBinarySearchTest.java   | 40 ++++++++++
 2 files changed, 114 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
 create mode 100644 src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java

diff --git a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
new file mode 100644
index 000000000000..8a02b30a9f0e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
@@ -0,0 +1,74 @@
+// Code by Pronay Debnath
+// Created:- 1/10/2023
+// File Name should be RecursiveBinarySearch.java
+// Explanation:- https://www.tutorialspoint.com/java-program-for-binary-search-recursive
+
+import java.util.*;
+
+// Create a SearchAlgorithm class with a generic type
+abstract class SearchAlgorithm<T extends Comparable<T>> {
+    // Abstract find method to be implemented by subclasses
+    public abstract int find(T[] arr, T target);
+}
+
+public class RecursiveBinarySearch<T extends Comparable<T>> extends SearchAlgorithm<T> {
+
+    // Override the find method as required
+    @Override
+    public int find(T[] arr, T target) {
+        // Call the recursive binary search function
+        return binsear(arr, 0, arr.length - 1, target);
+    }
+
+    // Recursive binary search function
+    public int binsear(T[] arr, int left, int right, T target) {
+        if (right >= left) {
+            int mid = left + (right - left) / 2;
+
+            // Compare the element at the middle with the target
+            int comparison = arr[mid].compareTo(target);
+
+            // If the element is equal to the target, return its index
+            if (comparison == 0) {
+                return mid;
+            }
+
+            // If the element is greater than the target, search in the left subarray
+            if (comparison > 0) {
+                return binsear(arr, left, mid - 1, target);
+            }
+
+            // Otherwise, search in the right subarray
+            return binsear(arr, mid + 1, right, target);
+        }
+
+        // Element is not present in the array
+        return -1;
+    }
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        // User inputs
+        System.out.print("Enter the number of elements in the array: ");
+        int n = sc.nextInt();
+
+        Integer[] a = new Integer[n]; // You can change the array type as needed
+
+        System.out.println("Enter the elements in sorted order:");
+
+        for (int i = 0; i < n; i++) {
+            a[i] = sc.nextInt();
+        }
+
+        System.out.print("Enter the target element to search for: ");
+        int t = sc.nextInt();
+
+        RecursiveBinarySearch<Integer> searcher = new RecursiveBinarySearch<>();
+        int res = searcher.find(a, t);
+
+        if (res == -1)
+            System.out.println("Element not found in the array.");
+        else
+            System.out.println("Element found at index " + res);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java
new file mode 100644
index 000000000000..3b2cdead1c6b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java
@@ -0,0 +1,40 @@
+// Created by Pronay Debnath
+// Date:- 1/10/2023
+// Test file updated with JUnit tests
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test; // Import the JUnit 5 Test annotation
+
+public class RecursiveBinarySearchTest {
+
+    @Test
+    public void testBinarySearch() {
+        // Create an instance of GenericBinarySearch
+        RecursiveBinarySearch<Integer> searcher = new RecursiveBinarySearch<>();
+
+        // Test case 1: Element found in the array
+        Integer[] arr1 = {1, 2, 3, 4, 5};
+        int target1 = 3;
+        int result1 = searcher.binsear(arr1, 0, arr1.length - 1, target1);
+        assertEquals(2, result1);
+
+        // Test case 2: Element not found in the array
+        Integer[] arr2 = {1, 2, 3, 4, 5};
+        int target2 = 6;
+        int result2 = searcher.binsear(arr2, 0, arr2.length - 1, target2);
+        assertEquals(-1, result2);
+
+        // Test case 3: Element found at the beginning of the array
+        Integer[] arr3 = {10, 20, 30, 40, 50};
+        int target3 = 10;
+        int result3 = searcher.binsear(arr3, 0, arr3.length - 1, target3);
+        assertEquals(0, result3);
+
+        // Test case 4: Element found at the end of the array
+        Integer[] arr4 = {10, 20, 30, 40, 50};
+        int target4 = 50;
+        int result4 = searcher.binsear(arr4, 0, arr4.length - 1, target4);
+        assertEquals(4, result4);
+    }
+}

From 37b3844b98712d2f46ed2296f307cbb8539dd748 Mon Sep 17 00:00:00 2001
From: Bharath Sanjeevi T <119755499+BharathSanjeeviT@users.noreply.github.com>
Date: Sun, 1 Oct 2023 20:58:37 +0530
Subject: [PATCH 0022/1338] Add `SecondMinMax` (#4432)

* Added Second Min/Max program

* Clang-format-lint error resolved

* Clang-format-error 2

* Added Program to find Second Minimum/Maximum element

* Test File & few changes

* Clang-lint-error resolved

* Maven Build Error Resolved

* Clang-lint-error resolved

* Clang-lint-error resolved 2

* Changes Resolved

* Test Arguements are Streamed

* Clang-lint-error resolved

* incresed code reusability

* Added Program to find Second Min / Max

* Program to find Second Min / Max

* Program to find Second Minimum / Maximum

* Program to find Second Best Number

* style: mark `initialVal` as `final`

* style: resolve `MultipleVariableDeclarations`

Each variable declaration must be in its own statement.

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/maths/SecondMinMax.java | 60 +++++++++++++++++++
 .../thealgorithms/maths/SecondMinMaxTest.java | 58 ++++++++++++++++++
 2 files changed, 118 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/SecondMinMax.java
 create mode 100644 src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java

diff --git a/src/main/java/com/thealgorithms/maths/SecondMinMax.java b/src/main/java/com/thealgorithms/maths/SecondMinMax.java
new file mode 100644
index 000000000000..e5a2d3b89085
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/SecondMinMax.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.maths;
+
+import java.util.function.BiPredicate;
+
+public final class SecondMinMax {
+
+    /**
+     * Utility class for finding second maximum or minimum based on BiPredicate
+     * @exception IllegalArgumentException => if input array is of length less than 2 also if all elements are same
+     * @return the second minimum / maximum value from the input array
+     * @author Bharath Sanjeevi ( https://github.com/BharathSanjeeviT )
+     */
+
+    private SecondMinMax() {
+    }
+
+    private static int secondBest(final int[] arr, final int initialVal, final BiPredicate<Integer, Integer> isBetter) {
+        checkInput(arr);
+        int best = initialVal;
+        int secBest = initialVal;
+        for (final int num : arr) {
+            if (isBetter.test(num, best)) {
+                secBest = best;
+                best = num;
+            } else if ((isBetter.test(num, secBest)) && (num != best)) {
+                secBest = num;
+            }
+        }
+        checkOutput(secBest, initialVal);
+        return secBest;
+    }
+
+    /**
+     * @brief Finds the Second minimum / maximum value from the array
+     * @param arr the input array
+     * @exception IllegalArgumentException => if input array is of length less than 2 also if all elements are same
+     * @return the second minimum / maximum value from the input array
+     * @author Bharath Sanjeevi ( https://github.com/BharathSanjeeviT )
+     */
+
+    public static int findSecondMin(final int[] arr) {
+        return secondBest(arr, Integer.MAX_VALUE, (a, b) -> a < b);
+    }
+
+    public static int findSecondMax(final int[] arr) {
+        return secondBest(arr, Integer.MIN_VALUE, (a, b) -> a > b);
+    }
+
+    private static void checkInput(final int[] arr) {
+        if (arr.length < 2) {
+            throw new IllegalArgumentException("Input array must have length of at least two");
+        }
+    }
+
+    private static void checkOutput(final int secNum, final int initialVal) {
+        if (secNum == initialVal) {
+            throw new IllegalArgumentException("Input array should have at least 2 distinct elements");
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java b/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java
new file mode 100644
index 000000000000..c744614e5cfa
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class SecondMinMaxTest {
+
+    private static final String EXP_MSG_ARR_LEN_LESS_2 = "Input array must have length of at least two";
+    private static final String EXP_MSG_ARR_SAME_ELE = "Input array should have at least 2 distinct elements";
+
+    public static class TestCase {
+        public TestCase(final int[] inInputArray, final int inSecondMin, final int inSecondMax) {
+            inputArray = inInputArray;
+            secondMin = inSecondMin;
+            secondMax = inSecondMax;
+        }
+        final int[] inputArray;
+        final int secondMin;
+        final int secondMax;
+    }
+
+    @Test
+    public void testForEmptyInputArray() {
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> SecondMinMax.findSecondMin(new int[] {}));
+        assertEquals(exception.getMessage(), EXP_MSG_ARR_LEN_LESS_2);
+    }
+
+    @Test
+    public void testForArrayWithSingleElement() {
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> SecondMinMax.findSecondMax(new int[] {1}));
+        assertEquals(exception.getMessage(), EXP_MSG_ARR_LEN_LESS_2);
+    }
+
+    @Test
+    public void testForArrayWithSameElements() {
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> SecondMinMax.findSecondMin(new int[] {1, 1, 1, 1}));
+        assertEquals(exception.getMessage(), EXP_MSG_ARR_SAME_ELE);
+    }
+
+    @ParameterizedTest
+    @MethodSource("inputStream")
+    void numberTests(final TestCase tc) {
+        Assertions.assertEquals(tc.secondMax, SecondMinMax.findSecondMax(tc.inputArray));
+        Assertions.assertEquals(tc.secondMin, SecondMinMax.findSecondMin(tc.inputArray));
+    }
+
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of(new TestCase(new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, 2, 9)), Arguments.of(new TestCase(new int[] {5, 4, 5, 5, 5}, 5, 4)), Arguments.of(new TestCase(new int[] {-1, 0}, 0, -1)),
+            Arguments.of(new TestCase(new int[] {-10, -9, -8, -7, -6, -5, -4, -3, -2, -1}, -9, -2)), Arguments.of(new TestCase(new int[] {3, -2, 3, 9, -4, -4, 8}, -2, 8)));
+    }
+}

From edb0489440814cd45a4001384b00e8b87c30d6a6 Mon Sep 17 00:00:00 2001
From: Prabhat-Kumar <prabhatkumarverma42@gmail.com>
Date: Sun, 1 Oct 2023 21:31:32 +0530
Subject: [PATCH 0023/1338] [FEATURE] #4486  QuickSort Algo for LinkedList
 (#4487)

* Added code to find Articulation Points and Bridges

* tried to solve clang-formant test

* removed new line at EOF to get lint to pass

* feature: Added Ahocorasick Algorithm

* fixed lint using clang-format

* Added QuickSort Algorithm for linked list

* removed datastructures/graphs/ArticulationPointsAndBridges and string/AhoCorasick.java from this branch

* Added datastructures/lists/SinglyLinkedList class, Replaced ListNode class

* Modified some comments

* Added tests in QuickSortLinkedListsTest.java

* removed main as added a test file to test test-cases

* test file for QuickSortLinkedLinst.java
---
 .../lists/QuickSortLinkedList.java            | 170 ++++++++++++++++++
 .../lists/QuickSortLinkedListTest.java        |  66 +++++++
 2 files changed, 236 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java
new file mode 100644
index 000000000000..36b6e9c62cbe
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java
@@ -0,0 +1,170 @@
+package com.thealgorithms.datastructures.lists;
+/*
+ *
+ * @aurthor - Prabhat-Kumar-42
+ * @github - https://github.com/Prabhat-Kumar-42
+ *
+ * Problem :
+ *    QuickSort on Linked List
+ *
+ * Note: Taking head as pivot in current implementation.
+ *        N represents NULL node
+ *    Example:
+ *
+ *      -> Given Linked List :
+ *            5 -> 3 -> 8 -> 1 -> 10 -> 2 -> 7 -> 4 -> 9 -> 6
+ *
+ *      -> How Sorting will work according to the QuickSort Algo written below
+ *
+ *      current pivot : 5
+ *      List lessThanPivot : 3 -> 1 -> 2 -> 4
+ *      List greaterThanPivot : 5 -> 8 -> 10 -> 7 -> 9 -> 6
+ *
+ *      -> reccur for lessThanPivot and greaterThanPivot
+ *
+ *            lessThanPivot :
+ *                current pivot : 3
+ *                lessThanPivot : 1 -> 2
+ *                greaterThanPivot : 4
+ *
+ *             greaterThanPivot:
+ *                 current pivot : 5
+ *                 lessThanPivot : null
+ *                 greaterThanPivot : 8 -> 10 -> 7 -> 9 -> 6
+ *
+ *        By following the above pattern, reccuring tree will form like below :
+ *
+ *        List-> 5 -> 3 -> 8 -> 1 -> 10 -> 2 -> 7 -> 4 -> 9 -> 6
+ *
+ *        Pivot :                  5
+ *                                /\
+ *                               /  \
+ *                              /    \
+ *                             /      \
+ *                            /        \
+ *        List: (3 -> 1 -> 2 -> 4)   (5 -> 8 -> 10 -> 7 -> 9 -> 6)
+ *        Pivot :          3               5
+ *                        /\              /\
+ *                       /  \            /  \
+ *                      /    \          /    \
+ *                     /      \        /      \
+ *         List:   (1 -> 2)   (4)   (N)   (8 -> 10 -> 7 -> 9 -> 6)
+ *         Pivot:     1        4                8
+ *                   /\       /\               /\
+ *                  /  \     /  \             /  \
+ *                 /    \   /    \           /    \
+ *         List:  (N)  (2) (N)   (N)   (6 -> 7)   (9 -> 10)
+ *         Pivot:       2                  6         9
+ *                     /\                 /\        /\
+ *                    /  \               /  \      /  \
+ *                   /    \             /    \    /    \
+ *         List:   (N)   (N)          (N)   (7) (N)   (10)
+ *         Pivot:                            7          10
+ *                                          /\          /\
+ *                                         /  \        /  \
+ *                                        /    \      /    \
+ *                                       (N)   (N)   (N)   (N)
+ *
+ *
+ *      -> After this the tree will reccur back (or backtrack)
+ *         and the returning list from left and right subtree will attach
+ *         themselves around pivot.
+ *         i.e. ,
+ *                  (listFromLeftSubTree) -> (Pivot) -> (listFromRightSubtree)
+ *
+ *         This will continue until whole list is merged back
+ *
+ *          eg :
+ *             Megring the above Tree back we get :
+ *
+ *          List: (1 -> 2)        (4)           (6 -> 7)         (9 -> 10)
+ *                  \             /                  \             /
+ *                   \           /                    \           /
+ *                    \         /                      \         /
+ *                     \       /                        \       /
+ *                      \     /                          \     /
+ *                       \   /                            \   /
+ *                        \ /                              \ /
+ *          Pivot:         3                                8
+ *          List:   (1 -> 2 -> 3 -> 4)            (6 -> 7 -> 8 -> 9 -> 10)
+ *                                  \              /
+ *                                   \            /
+ *                                    \          /
+ *                                     \        /
+ *                                      \      /
+ *                                       \    /
+ *                                        \  /
+ *                                         \/
+ *          Pivot:                          5
+ *          List:      (1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7 -> 8 -> 9 -> 10)
+ *
+ *
+ *      -> This will result in a sorted Linked List
+ */
+
+public class QuickSortLinkedList {
+
+    private SinglyLinkedList list = null; // Linked list
+    private Node head = null; // head of the list
+    // Counstructor
+    public QuickSortLinkedList(SinglyLinkedList list) {
+        this.list = list;
+        this.head = list.getHead();
+    }
+
+    // Function to sort a linked list using the Quick Sort algorithm
+    public void sortList() {
+        head = sortList(head);
+        list.setHead(head);
+    }
+    // helper function to apply QuickSort to the stored list
+    public Node sortList(Node head) {
+        if (head == null || head.next == null) {
+            return head;
+        }
+
+        // Choose the first element as the pivot
+        Node pivot = head;
+        head = head.next;
+        pivot.next = null;
+
+        Node lessHead = new Node(); // stores the nodes cantaining data less than pivot node
+        Node lessTail = lessHead; // tail of lessHead
+        Node greaterHead = new Node(); // stores the nodes cantaining data greater than pivot node
+        Node greaterTail = greaterHead; // tail of greaterHead
+
+        // Partition the list around the pivot
+        while (head != null) {
+            if (head.value < pivot.value) {
+                lessTail.next = head;
+                lessTail = lessTail.next;
+            } else {
+                greaterTail.next = head;
+                greaterTail = greaterTail.next;
+            }
+            head = head.next;
+        }
+
+        // Seperating lessHead and greaterHead to form two seperate linkedList
+        lessTail.next = null;
+        greaterTail.next = null;
+
+        // Recursively sort the sublists
+        Node sortedLess = sortList(lessHead.next);
+        Node sortedGreater = sortList(greaterHead.next);
+
+        // Combine the sorted sublists and pivot
+        if (sortedLess == null) {
+            pivot.next = sortedGreater;
+            return pivot;
+        } else {
+            Node current = sortedLess;
+            while (current.next != null) {
+                current = current.next;
+            }
+            current.next = pivot;
+            pivot.next = sortedGreater;
+            return sortedLess;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
new file mode 100644
index 000000000000..f4bcfd7fc40d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
@@ -0,0 +1,66 @@
+package com.thealgorithms.datastructures.lists;
+
+/**
+ * Test cases for QuickSortLinkedList
+ * Author: Prabhat-Kumar-42
+ * GitHub: https://github.com/Prabhat-Kumar-42
+ */
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class QuickSortLinkedListTest {
+
+    @Test
+    public void testSortEmptyList() {
+        SinglyLinkedList emptyList = new SinglyLinkedList();
+        QuickSortLinkedList sorter = new QuickSortLinkedList(emptyList);
+
+        // Test case: Sorting an empty list should result in an empty list
+        sorter.sortList();
+        assertNull(emptyList.getHead());
+    }
+
+    @Test
+    public void testSortSingleNodeList() {
+        SinglyLinkedList singleNodeList = new SinglyLinkedList();
+        singleNodeList.insert(5);
+        QuickSortLinkedList sorter = new QuickSortLinkedList(singleNodeList);
+
+        // Test case: Sorting a list with a single node should result in the same list
+        sorter.sortList();
+        assertEquals(5, singleNodeList.getHead().value);
+        assertNull(singleNodeList.getHead().next);
+    }
+
+    @Test
+    public void testSortMultipleElementsList() {
+        SinglyLinkedList list = new SinglyLinkedList();
+        list.insert(5);
+        list.insert(3);
+        list.insert(8);
+        list.insert(1);
+        list.insert(10);
+        list.insert(2);
+        list.insert(7);
+        list.insert(4);
+        list.insert(9);
+        list.insert(6);
+        QuickSortLinkedList sorter = new QuickSortLinkedList(list);
+
+        // Test case: Sorting a list with multiple elements
+        sorter.sortList();
+        assertEquals(1, list.getHead().value);
+        assertEquals(2, list.getHead().next.value);
+        assertEquals(3, list.getHead().next.next.value);
+        assertEquals(4, list.getHead().next.next.next.value);
+        assertEquals(5, list.getHead().next.next.next.next.value);
+        assertEquals(6, list.getHead().next.next.next.next.next.value);
+        assertEquals(7, list.getHead().next.next.next.next.next.next.value);
+        assertEquals(8, list.getHead().next.next.next.next.next.next.next.value);
+        assertEquals(9, list.getHead().next.next.next.next.next.next.next.next.value);
+        assertEquals(10, list.getHead().next.next.next.next.next.next.next.next.next.value);
+        assertNull(list.getHead().next.next.next.next.next.next.next.next.next.next);
+    }
+}

From f72b80b116673b3661ae4f55e50c4abbe9c0df49 Mon Sep 17 00:00:00 2001
From: Arin <136636751+asapekia@users.noreply.github.com>
Date: Sun, 1 Oct 2023 21:35:27 +0530
Subject: [PATCH 0024/1338] rewrote as parameterized tests (#4458)

* rewrote as parameterized tests

* formatting issue resolved

* added test with different prime number q

* style: run `clang-format`

* tests: add missing test case

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../searches/RabinKarpAlgorithmTest.java      | 56 +++----------------
 1 file changed, 9 insertions(+), 47 deletions(-)

diff --git a/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java b/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java
index 6841fdac33f4..4689dccf08fd 100644
--- a/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java
@@ -1,56 +1,18 @@
 package com.thealgorithms.searches;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 class RabinKarpAlgorithmTest {
-
     RabinKarpAlgorithm RKA = new RabinKarpAlgorithm();
-    int q = 101;
-
-    @Test
-    // valid test case
-    public void RabinKarpAlgorithmTestExample() {
-        String txt = "This is an example for rabin karp algorithmn";
-        String pat = "algorithmn";
-        int value = RKA.search(pat, txt, q);
-        assertEquals(value, 34);
-    }
-
-    @Test
-    // valid test case
-    public void RabinKarpAlgorithmTestFront() {
-        String txt = "AAABBDDG";
-        String pat = "AAA";
-        int value = RKA.search(pat, txt, q);
-        assertEquals(value, 0);
-    }
-
-    @Test
-    // valid test case
-    public void RabinKarpAlgorithmTestMiddle() {
-        String txt = "AAABBCCBB";
-        String pat = "BBCC";
-        int value = RKA.search(pat, txt, q);
-        assertEquals(value, 3);
-    }
-
-    @Test
-    // valid test case
-    public void RabinKarpAlgorithmTestLast() {
-        String txt = "AAAABBBBCCC";
-        String pat = "CCC";
-        int value = RKA.search(pat, txt, q);
-        assertEquals(value, 8);
-    }
 
-    @Test
-    // valid test case
-    public void RabinKarpAlgorithmTestNotFound() {
-        String txt = "ABCBCBCAAB";
-        String pat = "AADB";
-        int value = RKA.search(pat, txt, q);
-        assertEquals(value, -1);
+    @ParameterizedTest
+    @CsvSource({"This is an example for rabin karp algorithmn, algorithmn, 101", "AAABBDDG, AAA, 137", "AAABBCCBB, BBCC, 101", "AAABBCCBB, BBCC, 131", "AAAABBBBCCC, CCC, 41", "ABCBCBCAAB, AADB, 293", "Algorithm The Algorithm, Algorithm, 101"})
+    void RabinKarpAlgorithmTestExample(String txt, String pat, int q) {
+        int indexFromOurAlgorithm = RKA.search(pat, txt, q);
+        int indexFromLinearSearch = txt.indexOf(pat);
+        assertEquals(indexFromOurAlgorithm, indexFromLinearSearch);
     }
 }

From 8dc5505323708dc0963ba7871afac85cf9db60f7 Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Sun, 1 Oct 2023 20:21:29 +0200
Subject: [PATCH 0025/1338] Add FindMaxRecursionTest (#4431)

* Update FindMaxRecursion.java

* Create FindMaxRecusionTest.java

* Update and rename FindMaxRecusionTest.java to FindMaxRecursionTest.java

* Update FindMaxRecursion.java

* Update FindMaxRecursion.java

* Update src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/FindMaxRecursion.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update FindMaxRecursion.java

* Update FindMaxRecursionTest.java

* Update FindMaxRecursionTest.java

* Update FindMaxRecursion.java

* Update src/main/java/com/thealgorithms/maths/FindMaxRecursion.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update FindMaxRecursion.java

* Update FindMaxRecursion.java

* Update FindMaxRecursion.java

* Update FindMaxRecursion.java

* Update FindMaxRecursion.java

* Update src/main/java/com/thealgorithms/maths/FindMaxRecursion.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../thealgorithms/maths/FindMaxRecursion.java | 30 +++++--------------
 .../maths/FindMaxRecursionTest.java           | 28 +++++++++++++++++
 2 files changed, 36 insertions(+), 22 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java

diff --git a/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java b/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java
index f6acafd2684c..574fe5f2b1b8 100644
--- a/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java
+++ b/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java
@@ -1,26 +1,9 @@
 package com.thealgorithms.maths;
 
-import java.util.Arrays;
-import java.util.Random;
+public final class FindMaxRecursion {
 
-public class FindMaxRecursion {
-
-    public static void main(String[] args) {
-        Random rand = new Random();
-
-        /* rand size */
-        int size = rand.nextInt(100) + 1;
-        int[] array = new int[size];
-
-        /* init array with rand numbers */
-        for (int i = 0; i < size; i++) {
-            array[i] = rand.nextInt() % 100;
-        }
-
-        assert max(array) == Arrays.stream(array).max().getAsInt();
-        assert max(array, 0, array.length - 1) == Arrays.stream(array).max().getAsInt();
+    private FindMaxRecursion() {
     }
-
     /**
      * Get max of array using divide and conquer algorithm
      *
@@ -29,7 +12,10 @@ public static void main(String[] args) {
      * @param high the index of the last element
      * @return max of {@code array}
      */
-    public static int max(int[] array, int low, int high) {
+    public static int max(final int[] array, final int low, final int high) {
+        if (array.length == 0) {
+            throw new IllegalArgumentException("array must be non-empty.");
+        }
         if (low == high) {
             return array[low]; // or array[high]
         }
@@ -48,7 +34,7 @@ public static int max(int[] array, int low, int high) {
      * @param array contains elements
      * @return max value of {@code array}
      */
-    public static int max(int[] array) {
-        return array.length == 1 ? array[0] : max(array, 0, array.length);
+    public static int max(final int[] array) {
+        return max(array, 0, array.length - 1);
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java b/src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java
new file mode 100644
index 000000000000..d54cae67209f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class FindMaxRecursionTest {
+
+    @ParameterizedTest
+    @MethodSource("inputStream")
+    void numberTests(int expected, int[] input) {
+        Assertions.assertEquals(expected, FindMaxRecursion.max(input));
+    }
+
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of(5, new int[] {5, 5, 5, 5, 5}), Arguments.of(0, new int[] {-1, 0}), Arguments.of(-1, new int[] {-10, -9, -8, -7, -6, -5, -4, -3, -2, -1}), Arguments.of(9, new int[] {3, -2, 3, 9, -4, -4, 8}), Arguments.of(3, new int[] {3}));
+    }
+
+    @Test
+    public void testFindMaxThrowsExceptionForEmptyInput() {
+        assertThrows(IllegalArgumentException.class, () -> FindMaxRecursion.max(new int[] {}));
+    }
+}

From 628357263720ff7c85a106ec187ccb8296998b0e Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 1 Oct 2023 21:55:37 +0200
Subject: [PATCH 0026/1338] Ask contributors to create drafts (#4522)

---
 .github/pull_request_template.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index 01645d5bfedf..ce1d87a2c62e 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -1,3 +1,11 @@
+<!--
+Thank you for your contribution!
+In order to reduce the number of notifications sent to the maintainers, please:
+- create your PR as draft, cf. https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/about-pull-requests#draft-pull-requests,
+- make sure that all of the CI checks pass,
+- mark your PR as ready for review, cf. https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/changing-the-stage-of-a-pull-request#marking-a-pull-request-as-ready-for-review
+-->
+
 <!-- For completed items, change [ ] to [x] -->
 
 - [ ] I have read [CONTRIBUTING.md](https://github.com/TheAlgorithms/Java/blob/master/CONTRIBUTING.md).

From 536978919dc79af9bf25c57ebb90802d1830784e Mon Sep 17 00:00:00 2001
From: Bama Charan Chhandogi <b.c.chhandogi@gmail.com>
Date: Tue, 3 Oct 2023 12:13:49 +0530
Subject: [PATCH 0027/1338] Add reverse k group in LinkedList algorithm (#4532)

---
 .../datastructures/lists/ReverseKGroup.java   | 45 ++++++++++++
 .../lists/ReverseKGroupTest.java              | 72 +++++++++++++++++++
 2 files changed, 117 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java b/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
new file mode 100644
index 000000000000..bd599e2ab91f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
@@ -0,0 +1,45 @@
+package com.thealgorithms.datastructures.lists;
+
+/**
+ * Reverse K Group LinkedList (https://www.topcoder.com/thrive/articles/reverse-node-in-k-group)
+ * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
+ */
+
+public class ReverseKGroup {
+    public int length(Node head) {
+        Node curr = head;
+        int count = 0;
+        while (curr != null) {
+            curr = curr.next;
+            count++;
+        }
+        return count;
+    }
+    // reverse function
+    public Node reverse(Node head, int count, int k) {
+        if (count < k) {
+            return head;
+        }
+        Node prev = null;
+        int count1 = 0;
+        Node curr = head;
+        Node Next = null;
+        while (curr != null && count1 < k) {
+            Next = curr.next;
+            curr.next = prev;
+            prev = curr;
+            curr = Next;
+            count1++;
+        }
+
+        if (Next != null) {
+            head.next = reverse(Next, count - k, k);
+        }
+        return prev;
+    }
+    public Node reverseKGroup(Node head, int k) {
+        int count = length(head);
+        Node ans = reverse(head, count, k);
+        return ans;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java b/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
new file mode 100644
index 000000000000..8273b890e6ae
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
@@ -0,0 +1,72 @@
+package com.thealgorithms.datastructures.lists;
+
+/**
+ * Test cases for Reverse K Group LinkedList
+ * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
+ */
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class ReverseKGroupTest {
+
+    @Test
+    public void testReverseKGroupWithEmptyList() {
+        ReverseKGroup reverser = new ReverseKGroup();
+        assertNull(reverser.reverseKGroup(null, 3));
+    }
+
+    @Test
+    public void testReverseKGroupWithSingleNodeList() {
+        ReverseKGroup reverser = new ReverseKGroup();
+        Node singleNode = new Node(5);
+        Node result = reverser.reverseKGroup(singleNode, 2);
+        assertEquals(5, result.value);
+        assertNull(result.next);
+    }
+
+    @Test
+    public void testReverseKGroupWithKEqualTo2() {
+        ReverseKGroup reverser = new ReverseKGroup();
+
+        // Create a list with multiple elements (1 -> 2 -> 3 -> 4 -> 5)
+        Node head;
+        head = new Node(1);
+        head.next = new Node(2);
+        head.next.next = new Node(3);
+        head.next.next.next = new Node(4);
+        head.next.next.next.next = new Node(5);
+
+        // Test reverse with k=2
+        Node result1 = reverser.reverseKGroup(head, 2);
+        assertEquals(2, result1.value);
+        assertEquals(1, result1.next.value);
+        assertEquals(4, result1.next.next.value);
+        assertEquals(3, result1.next.next.next.value);
+        assertEquals(5, result1.next.next.next.next.value);
+        assertNull(result1.next.next.next.next.next);
+    }
+
+    @Test
+    public void testReverseKGroupWithKEqualTo3() {
+        ReverseKGroup reverser = new ReverseKGroup();
+
+        // Create a list with multiple elements (1 -> 2 -> 3 -> 4 -> 5)
+        Node head;
+        head = new Node(1);
+        head.next = new Node(2);
+        head.next.next = new Node(3);
+        head.next.next.next = new Node(4);
+        head.next.next.next.next = new Node(5);
+
+        // Test reverse with k=3
+        Node result = reverser.reverseKGroup(head, 3);
+        assertEquals(3, result.value);
+        assertEquals(2, result.next.value);
+        assertEquals(1, result.next.next.value);
+        assertEquals(4, result.next.next.next.value);
+        assertEquals(5, result.next.next.next.next.value);
+        assertNull(result.next.next.next.next.next);
+    }
+}

From 5f5a61de872f5894097564ed769299dc5134f011 Mon Sep 17 00:00:00 2001
From: Bama Charan Chhandogi <b.c.chhandogi@gmail.com>
Date: Tue, 3 Oct 2023 19:46:14 +0530
Subject: [PATCH 0028/1338] Add median of matrix (#4590)

---
 .../thealgorithms/misc/MedianOfMatrix.java    | 30 ++++++++++++++++
 .../misc/MedianOfMatrixtest.java              | 34 +++++++++++++++++++
 2 files changed, 64 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
 create mode 100644 src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java

diff --git a/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java b/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
new file mode 100644
index 000000000000..4d8b980f2409
--- /dev/null
+++ b/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
@@ -0,0 +1,30 @@
+package com.thealgorithms.misc;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Median of Matrix (https://medium.com/@vaibhav.yadav8101/median-in-a-row-wise-sorted-matrix-901737f3e116)
+ * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
+ */
+
+public final class MedianOfMatrix {
+
+    public static int median(List<List<Integer>> matrix) {
+        // Flatten the matrix into a 1D list
+        List<Integer> linear = new ArrayList<>();
+        for (List<Integer> row : matrix) {
+            linear.addAll(row);
+        }
+
+        // Sort the 1D list
+        Collections.sort(linear);
+
+        // Calculate the middle index
+        int mid = (0 + linear.size() - 1) / 2;
+
+        // Return the median
+        return linear.get(mid);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java b/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java
new file mode 100644
index 000000000000..c1fa30d6a1cd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class MedianOfMatrixtest {
+
+    @Test
+    public void testMedianWithOddNumberOfElements() {
+        List<List<Integer>> matrix = new ArrayList<>();
+        matrix.add(Arrays.asList(1, 3, 5));
+        matrix.add(Arrays.asList(2, 4, 6));
+        matrix.add(Arrays.asList(7, 8, 9));
+
+        int result = MedianOfMatrix.median(matrix);
+
+        assertEquals(5, result);
+    }
+
+    @Test
+    public void testMedianWithEvenNumberOfElements() {
+        List<List<Integer>> matrix = new ArrayList<>();
+        matrix.add(Arrays.asList(2, 4));
+        matrix.add(Arrays.asList(1, 3));
+
+        int result = MedianOfMatrix.median(matrix);
+
+        assertEquals(2, result);
+    }
+}

From 9795bada907a533182496a56ccf8644cc7c274a4 Mon Sep 17 00:00:00 2001
From: Shreyash Kashyap <76607993+SYK-08@users.noreply.github.com>
Date: Tue, 3 Oct 2023 19:52:19 +0530
Subject: [PATCH 0029/1338] Update Readme.md (#4561)

---
 .../datastructures/hashmap/Readme.md             | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/Readme.md b/src/main/java/com/thealgorithms/datastructures/hashmap/Readme.md
index 7f925989c4f3..252b06ea59b0 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/Readme.md
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/Readme.md
@@ -27,27 +27,27 @@ Internally HashMap contains an array of Node and a node is represented as a clas
 - V value
 - Node next
 
-It can be seen that the node is containing a reference to its own object. So it’s a linked list.
+It can be seen that the node contains a reference to its object. So it’s a linked list.
 
 ## Performance of HashMap
-Performance of HashMap depends on 2 parameters which are named as follows:
+The performance of HashMap depends on 2 parameters which are named as follows:
 - Initial Capacity
 - Load Factor
 
 
-**Initial Capacity**: It is the capacity of HashMap at the time of its creation (It is the number of buckets a HashMap can hold when the HashMap is instantiated). In java, it is 2^4=16 initially, meaning it can hold 16 key-value pairs.
+**Initial Capacity**: It is the capacity of HashMap at the time of its creation (It is the number of buckets a HashMap can hold when the HashMap is instantiated). In Java, it is 2^4=16 initially, meaning it can hold 16 key-value pairs.
 
-**Load Factor**: It is the percent value of the capacity after which the capacity of Hashmap is to be increased (It is the percentage fill of buckets after which Rehashing takes place). In java, it is 0.75f by default, meaning the rehashing takes place after filling 75% of the capacity.
+**Load Factor**: It is the percent value of the capacity after which the capacity of Hashmap is to be increased (It is the percentage fill of buckets after which Rehashing takes place). In Java, it is 0.75f by default, meaning the rehashing takes place after filling 75% of the capacity.
 
-**Threshold**: It is the product of Load Factor and Initial Capacity. In java, by default, it is (16 * 0.75 = 12). That is, Rehashing takes place after inserting 12 key-value pairs into the HashMap.
+**Threshold**: It is the product of Load Factor and Initial Capacity. In Java, by default, it is (16 * 0.75 = 12). That is, Rehashing takes place after inserting 12 key-value pairs into the HashMap.
 
-**Rehashing** : It is the process of doubling the capacity of the HashMap after it reaches its Threshold. In java, HashMap continues to rehash(by default) in the following sequence – 2^4, 2^5, 2^6, 2^7, …. so on. 
+**Rehashing** : It is the process of doubling the capacity of the HashMap after it reaches its Threshold. In Java, HashMap continues to rehash(by default) in the following sequence – 2^4, 2^5, 2^6, 2^7, …. so on. 
 
-If the initial capacity is kept higher then rehashing will never be done. But by keeping it higher increases the time complexity of iteration. So it should be chosen very cleverly to increase performance. The expected number of values should be taken into account to set the initial capacity. The most generally preferred load factor value is 0.75 which provides a good deal between time and space costs. The load factor’s value varies between 0 and 1. 
+If the initial capacity is kept higher then rehashing will never be done. But keeping it higher increases the time complexity of iteration. So it should be chosen very cleverly to increase performance. The expected number of values should be taken into account to set the initial capacity. The most generally preferred load factor value is 0.75 which provides a good deal between time and space costs. The load factor’s value varies between 0 and 1. 
 
 ```
 Note: From Java 8 onward, Java has started using Self Balancing BST instead of a linked list for chaining. 
-The advantage of self-balancing bst is, we get the worst case (when every key maps to the same slot) search time is O(Log n). 
+The advantage of self-balancing bst is, that we get the worst case (when every key maps to the same slot) search time is O(Log n). 
 ```
 
 Java has two hash table classes: HashTable and HashMap. In general, you should use a HashMap.

From 329cc3bcf9bc7d43c358f5d7e635a7d9db99890a Mon Sep 17 00:00:00 2001
From: Aman <84791435+Aman28801@users.noreply.github.com>
Date: Tue, 3 Oct 2023 22:12:56 +0530
Subject: [PATCH 0030/1338] Added MirrorOfMatrix.java (#4461)

* Added MirrorOfMatrix.java

* Fixing Linting Issue

* Fixing Linting Issue

* Fixing Linting Issue

* Fixing Linting Issue

* Fixing Linting Issue

* Fixing Linting Issue

* Fixing Linting Issue

* Fixing Linting Issue

* Changes Done

* Update src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Changes Done

* Added MirrorOfMatrixTest.java

* Added MirrorOfMatrixTest.java

* Linting Error in Test

* Linting Error in Test

* Linting Error in Test

* trying to fix build error

* trying to fix build error

* final

* Update src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Changing Description

* Final

* Update src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Final

* Update src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Changes

* Changes

* Linting Issue

* Linting Issue

* Linting Issue

* Changes

* Fixing Minor Linting Issue

* Fixing Minor Linting Issue

* Final

* Update src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Changes

* Linting Issue

* Linting Issue

* Linting Issue

* Linting Issue

* Update src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Changes

* Changes

* fix: use proper size in `checkInput`

* style: basic linting

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Co-authored-by: vil02 <vil02@o2.pl>
---
 .../thealgorithms/misc/MirrorOfMatrix.java    | 57 +++++++++++++++++++
 .../misc/MirrorOfMatrixTest.java              | 53 +++++++++++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java
 create mode 100644 src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java

diff --git a/src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java b/src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java
new file mode 100644
index 000000000000..89dfce3fe049
--- /dev/null
+++ b/src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java
@@ -0,0 +1,57 @@
+package com.thealgorithms.misc;
+
+// Problem Statement
+/*
+We have given an array of m x n (where m is the number of rows and n is the number of columns).
+Print the new matrix in such a way that the new matrix is the mirror image of the original matrix.
+
+The Original matrix is:   |   The Mirror matrix is:
+1	2	3	              |   3	 2	 1
+4	5	6	              |   6	 5	 4
+7	8	9	              |   9	 8	 7
+
+@author - Aman (https://github.com/Aman28801)
+*/
+
+public final class MirrorOfMatrix {
+    private MirrorOfMatrix() {
+    }
+
+    public static int[][] mirrorMatrix(final int[][] originalMatrix) {
+        if (originalMatrix == null) {
+            // Handle invalid input
+            return null;
+        }
+        if (originalMatrix.length == 0) {
+            return new int[0][0];
+        }
+
+        checkInput(originalMatrix);
+
+        int numRows = originalMatrix.length;
+        int numCols = originalMatrix[0].length;
+
+        int[][] mirroredMatrix = new int[numRows][numCols];
+
+        for (int i = 0; i < numRows; i++) {
+            mirroredMatrix[i] = reverseRow(originalMatrix[i]);
+        }
+        return mirroredMatrix;
+    }
+    private static int[] reverseRow(final int[] inRow) {
+        int[] res = new int[inRow.length];
+        for (int i = 0; i < inRow.length; ++i) {
+            res[i] = inRow[inRow.length - 1 - i];
+        }
+        return res;
+    }
+
+    private static void checkInput(final int[][] matrix) {
+        // Check if all rows have the same number of columns
+        for (int i = 1; i < matrix.length; i++) {
+            if (matrix[i].length != matrix[0].length) {
+                throw new IllegalArgumentException("The input is not a matrix.");
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java b/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java
new file mode 100644
index 000000000000..0da0cf0f804a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class MirrorOfMatrixTest {
+
+    @Test
+    void testMirrorMatrixRegularMatrix() {
+        int[][] originalMatrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+        int[][] expectedMirrorMatrix = {{3, 2, 1}, {6, 5, 4}, {9, 8, 7}};
+        int[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
+        assertArrayEquals(expectedMirrorMatrix, mirroredMatrix);
+    }
+
+    @Test
+    void testMirrorMatrixEmptyMatrix() {
+        int[][] originalMatrix = {};
+        int[][] expectedMirrorMatrix = {};
+        int[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
+        assertArrayEquals(expectedMirrorMatrix, mirroredMatrix);
+    }
+
+    @Test
+    void testMirrorMatrixSingleElementMatrix() {
+        int[][] originalMatrix = {{42}};
+        int[][] expectedMirrorMatrix = {{42}};
+        int[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
+        assertArrayEquals(expectedMirrorMatrix, mirroredMatrix);
+    }
+
+    @Test
+    void testMirrorMatrixMultipleRowsOneColumnMatrix() {
+        int[][] originalMatrix = {{1}, {2}, {3}, {4}};
+        int[][] expectedMirrorMatrix = {{1}, {2}, {3}, {4}};
+        int[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
+        assertArrayEquals(expectedMirrorMatrix, mirroredMatrix);
+    }
+
+    @Test
+    void testMirrorMatrixNullInput() {
+        int[][] originalMatrix = null;
+        assertNull(MirrorOfMatrix.mirrorMatrix(originalMatrix));
+    }
+
+    @Test
+    void testMirrotMarixThrows() {
+        assertThrows(IllegalArgumentException.class, () -> MirrorOfMatrix.mirrorMatrix(new int[][] {{1}, {2, 3}}));
+    }
+}

From 535230acae939a9bb601a82be6f2c20c75687c4d Mon Sep 17 00:00:00 2001
From: Vineet Chotaliya <105866260+Vineetttt@users.noreply.github.com>
Date: Tue, 3 Oct 2023 23:00:18 +0530
Subject: [PATCH 0031/1338] Add Greedy Algorithms (fixes #4493) (#4504)

---
 .../greedyalgorithms/ActivitySelection.java   | 40 ++++++++++++
 .../greedyalgorithms/CoinChange.java          | 35 ++++++++++
 .../greedyalgorithms/FractionalKnapsack.java  | 41 ++++++++++++
 .../greedyalgorithms/JobSequencing.java       | 65 +++++++++++++++++++
 .../ActivitySelectionTest.java                | 42 ++++++++++++
 .../greedyalgorithms/CoinChangeTest.java      | 58 +++++++++++++++++
 .../FractionalKnapsackTest.java               | 32 +++++++++
 .../greedyalgorithms/JobSequencingTest.java   | 23 +++++++
 8 files changed, 336 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java

diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java b/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
new file mode 100644
index 000000000000..0f704dd6ed55
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
@@ -0,0 +1,40 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+
+// Problem Link:  https://en.wikipedia.org/wiki/Activity_selection_problem
+
+public class ActivitySelection {
+    // Function to perform activity selection
+    public static ArrayList<Integer> activitySelection(int startTimes[], int endTimes[]) {
+        int n = startTimes.length;
+        int activities[][] = new int[n][3];
+
+        // Create a 2D array to store activities and their start/end times.
+        // Each row: [activity index, start time, end time]
+
+        for (int i = 0; i < n; i++) {
+            activities[i][0] = i; // Assign activity index
+            activities[i][1] = startTimes[i]; // Assign start time
+            activities[i][2] = endTimes[i]; // Assign end time
+        }
+
+        // Sort activities by their end times in ascending order.
+        Arrays.sort(activities, Comparator.comparingDouble(activity -> activity[2]));
+        int lastEndTime;
+        ArrayList<Integer> selectedActivities = new ArrayList<>();
+        selectedActivities.add(activities[0][0]);
+        lastEndTime = activities[0][2];
+
+        // Iterate through sorted activities to select compatible ones.
+        for (int i = 1; i < n; i++) {
+            if (activities[i][1] >= lastEndTime) {
+                selectedActivities.add(activities[i][0]);
+                lastEndTime = activities[i][2];
+            }
+        }
+        return selectedActivities;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java b/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
new file mode 100644
index 000000000000..2109e454fa4d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
@@ -0,0 +1,35 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+
+// Problem Link : https://en.wikipedia.org/wiki/Change-making_problem
+
+public class CoinChange {
+    // Function to solve the coin change problem
+    public static ArrayList<Integer> coinChangeProblem(int amount) {
+        // Define an array of coin denominations in descending order
+        Integer coins[] = {1, 2, 5, 10, 20, 50, 100, 500, 2000};
+
+        // Sort the coin denominations in descending order
+        Arrays.sort(coins, Comparator.reverseOrder());
+
+        int count = 0; // Variable to keep track of the total number of coins used
+        ArrayList<Integer> ans = new ArrayList<>(); // List to store selected coins
+
+        // Iterate through the coin denominations
+        for (int i = 0; i < coins.length; i++) {
+            // Check if the current coin denomination can be used to reduce the remaining amount
+            if (coins[i] <= amount) {
+                // Repeatedly subtract the coin denomination from the remaining amount
+                while (coins[i] <= amount) {
+                    count++; // Increment the count of coins used
+                    ans.add(coins[i]); // Add the coin to the list of selected coins
+                    amount -= coins[i]; // Update the remaining amount
+                }
+            }
+        }
+        return ans;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java b/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
new file mode 100644
index 000000000000..c5570f35c004
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
@@ -0,0 +1,41 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+// Problem Link: https://en.wikipedia.org/wiki/Continuous_knapsack_problem
+
+public class FractionalKnapsack {
+    // Function to perform fractional knapsack
+    public static int fractionalKnapsack(int weight[], int value[], int capacity) {
+        // Create a 2D array to store item indices and their value-to-weight ratios.
+        double ratio[][] = new double[weight.length][2];
+
+        // Populate the ratio array with item indices and their value-to-weight ratios.
+        for (int i = 0; i < weight.length; i++) {
+            ratio[i][0] = i; // Assign item index.
+            ratio[i][1] = value[i] / (double) weight[i]; // Calculate and assign value-to-weight ratio.
+        }
+
+        // Sort items by their value-to-weight ratios in descending order.
+        Arrays.sort(ratio, Comparator.comparingDouble(o -> o[1]));
+
+        int finalValue = 0; // Variable to store the final knapsack value.
+        double current = capacity; // Variable to track the remaining capacity of the knapsack.
+
+        // Iterate through the sorted items to select items for the knapsack.
+        for (int i = ratio.length - 1; i >= 0; i--) {
+            int index = (int) ratio[i][0]; // Get the item index.
+            if (current >= weight[index]) {
+                // If the entire item can fit in the knapsack, add its value.
+                finalValue += value[index];
+                current -= weight[index];
+            } else {
+                // If only a fraction of the item can fit, add a proportionate value.
+                finalValue += ratio[i][1] * current;
+                break; // Stop adding items to the knapsack since it's full.
+            }
+        }
+        return finalValue;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
new file mode 100644
index 000000000000..bf81e067bac1
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
@@ -0,0 +1,65 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+
+// Problem Link: https://en.wikipedia.org/wiki/Job-shop_scheduling
+
+public class JobSequencing {
+
+    // Define a Job class that implements Comparable for sorting by profit in descending order
+    static class Job implements Comparable<Job> {
+        char id;
+        int deadline;
+        int profit;
+
+        // Compare jobs by profit in descending order
+        @Override
+        public int compareTo(Job otherJob) {
+            return otherJob.profit - this.profit;
+        }
+
+        public Job(char id, int deadline, int profit) {
+            this.id = id;
+            this.deadline = deadline;
+            this.profit = profit;
+        }
+    }
+
+    // Function to print the job sequence
+    public static String findJobSequence(ArrayList<Job> jobs, int size) {
+        Boolean[] slots = new Boolean[size];
+        Arrays.fill(slots, false);
+
+        int result[] = new int[size];
+
+        // Iterate through jobs to find the optimal job sequence
+        for (int i = 0; i < size; i++) {
+            for (int j = jobs.get(i).deadline - 1; j >= 0; j--) {
+                if (!slots[j]) {
+                    result[j] = i;
+                    slots[j] = true;
+                    break;
+                }
+            }
+        }
+
+        // Create a StringBuilder to build the job sequence string
+        StringBuilder jobSequenceBuilder = new StringBuilder();
+        jobSequenceBuilder.append("Job Sequence: ");
+        for (int i = 0; i < jobs.size(); i++) {
+            if (slots[i]) {
+                jobSequenceBuilder.append(jobs.get(result[i]).id).append(" -> ");
+            }
+        }
+
+        // Remove the trailing " -> " from the job sequence
+        if (jobSequenceBuilder.length() >= 4) {
+            jobSequenceBuilder.setLength(jobSequenceBuilder.length() - 4);
+        }
+
+        // Return the job sequence as a string
+        return jobSequenceBuilder.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
new file mode 100644
index 000000000000..42263ac1de8a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
@@ -0,0 +1,42 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import org.junit.jupiter.api.Test;
+
+public class ActivitySelectionTest {
+    @Test
+    public void testActivitySelection() {
+        int start[] = {1, 3, 0, 5, 8, 5};
+        int end[] = {2, 4, 6, 7, 9, 9};
+
+        ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0, 1, 3, 4));
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testSingleActivity() {
+        int start[] = {1};
+        int end[] = {2};
+
+        ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0));
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testNoOverlap() {
+        int start[] = {1, 2, 3};
+        int end[] = {2, 3, 4};
+
+        ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0, 1, 2));
+
+        assertEquals(expected, result);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java
new file mode 100644
index 000000000000..e9d267712a05
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import org.junit.jupiter.api.Test;
+
+public class CoinChangeTest {
+    @Test
+    public void testCoinChangeProblemWithValidAmount() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(500, 50, 20, 20, 1));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(591);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithLargeAmount() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(2000));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(2000);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithPartialCoins2() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(500, 50, 20));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(570);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithSmallAmount() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(2, 1));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(3);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithLargeAmountAndMultipleDenominations() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(2000, 2000, 2000, 2000, 500, 500, 500, 100, 100, 100, 100, 50, 20, 20, 5, 2, 2));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(9999);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithAllDenominations() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(2000, 500, 100, 100, 100, 50, 20, 10, 5, 2, 1));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(2888);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithZeroAmount() {
+        ArrayList<Integer> expected = new ArrayList<>();
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(0);
+        assertEquals(expected, coins);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
new file mode 100644
index 000000000000..edbf0a09bcbd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
@@ -0,0 +1,32 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class FractionalKnapsackTest {
+
+    @Test
+    public void testFractionalKnapsackWithExampleCase() {
+        int weight[] = {10, 20, 30};
+        int value[] = {60, 100, 120};
+        int capacity = 50;
+        assertEquals(240, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
+    }
+
+    @Test
+    public void testFractionalKnapsackWithZeroCapacity() {
+        int weight[] = {10, 20, 30};
+        int value[] = {60, 100, 120};
+        int capacity = 0;
+        assertEquals(0, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
+    }
+
+    @Test
+    public void testFractionalKnapsackWithEmptyItems() {
+        int weight[] = {};
+        int value[] = {};
+        int capacity = 50;
+        assertEquals(0, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java
new file mode 100644
index 000000000000..8dd42bc7c5ec
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import org.junit.jupiter.api.Test;
+
+public class JobSequencingTest {
+    @Test
+    public void testJobSequencingWithExampleCase() {
+        ArrayList<JobSequencing.Job> jobs = new ArrayList<>();
+        jobs.add(new JobSequencing.Job('a', 2, 100));
+        jobs.add(new JobSequencing.Job('b', 1, 19));
+        jobs.add(new JobSequencing.Job('c', 2, 27));
+        jobs.add(new JobSequencing.Job('d', 1, 25));
+        jobs.add(new JobSequencing.Job('e', 3, 15));
+        Collections.sort(jobs);
+        String jobSequence = JobSequencing.findJobSequence(jobs, jobs.size());
+
+        assertEquals("Job Sequence: c -> a -> e", jobSequence);
+    }
+}

From 4fab7adfaa3679d8b41360d169b40ee18b9ed735 Mon Sep 17 00:00:00 2001
From: Arin <136636751+asapekia@users.noreply.github.com>
Date: Tue, 3 Oct 2023 23:02:59 +0530
Subject: [PATCH 0032/1338] code-clean-up (#4519)

* code-clean-up

* style: make `RabinKarpAlgorithm` a proper utility class

---------

Co-authored-by: arintripathi1 <arint@trainee.nrifintech.com>
Co-authored-by: vil02 <vil02@o2.pl>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../searches/RabinKarpAlgorithm.java          | 67 +++++++++----------
 .../searches/RabinKarpAlgorithmTest.java      |  3 +-
 2 files changed, 33 insertions(+), 37 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java b/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java
index 8343310d18bf..e774546423f4 100644
--- a/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java
+++ b/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java
@@ -1,50 +1,48 @@
 package com.thealgorithms.searches;
 
-// Following program is a Java implementation
-// of Rabin Karp Algorithm given in the CLRS book
+// Implementation of Rabin Karp Algorithm
 
-public class RabinKarpAlgorithm {
+public final class RabinKarpAlgorithm {
+    private RabinKarpAlgorithm() {
+    }
 
     // d is the number of characters in the input alphabet
-    public static final int d = 256;
+    private static final int d = 256;
+
+    public static int search(String pattern, String text, int primeNumber) {
 
-    /* pat -> pattern
-        txt -> text
-        q -> A prime number
-    */
-    public int search(String pat, String txt, int q) {
-        int index = -1; // note: -1 here represent not found, it is not an index
-        int M = pat.length();
-        int N = txt.length();
-        int i, j;
-        int p = 0; // hash value for pattern
-        int t = 0; // hash value for txt
+        int index = -1; // -1 here represents not found
+        int patternLength = pattern.length();
+        int textLength = text.length();
+        int hashForPattern = 0;
+        int hashForText = 0;
         int h = 1;
 
-        // The value of h would be "pow(d, M-1)%q"
-        for (i = 0; i < M - 1; i++) h = (h * d) % q;
+        // The value of h would be "pow(d, patternLength-1)%primeNumber"
+        for (int i = 0; i < patternLength - 1; i++) h = (h * d) % primeNumber;
 
         // Calculate the hash value of pattern and first
         // window of text
-        for (i = 0; i < M; i++) {
-            p = (d * p + pat.charAt(i)) % q;
-            t = (d * t + txt.charAt(i)) % q;
+        for (int i = 0; i < patternLength; i++) {
+            hashForPattern = (d * hashForPattern + pattern.charAt(i)) % primeNumber;
+            hashForText = (d * hashForText + text.charAt(i)) % primeNumber;
         }
 
         // Slide the pattern over text one by one
-        for (i = 0; i <= N - M; i++) {
-            // Check the hash values of current window of text
-            // and pattern. If the hash values match then only
-            // check for characters one by one
-            if (p == t) {
+        for (int i = 0; i <= textLength - patternLength; i++) {
+            /* Check the hash values of current window of text
+               and pattern. If the hash values match then only
+               check for characters one by one*/
+
+            int j = 0;
+            if (hashForPattern == hashForText) {
                 /* Check for characters one by one */
-                for (j = 0; j < M; j++) {
-                    if (txt.charAt(i + j) != pat.charAt(j)) break;
+                for (j = 0; j < patternLength; j++) {
+                    if (text.charAt(i + j) != pattern.charAt(j)) break;
                 }
 
-                // if p == t and pat[0...M-1] = txt[i, i+1, ...i+M-1]
-                if (j == M) {
-                    System.out.println("Pattern found at index " + i);
+                // if hashForPattern == hashForText and pattern[0...patternLength-1] = text[i, i+1, ...i+patternLength-1]
+                if (j == patternLength) {
                     index = i;
                     return index;
                 }
@@ -52,12 +50,11 @@ public int search(String pat, String txt, int q) {
 
             // Calculate hash value for next window of text: Remove
             // leading digit, add trailing digit
-            if (i < N - M) {
-                t = (d * (t - txt.charAt(i) * h) + txt.charAt(i + M)) % q;
+            if (i < textLength - patternLength) {
+                hashForText = (d * (hashForText - text.charAt(i) * h) + text.charAt(i + patternLength)) % primeNumber;
 
-                // We might get negative value of t, converting it
-                // to positive
-                if (t < 0) t = (t + q);
+                // handling negative hashForText
+                if (hashForText < 0) hashForText = (hashForText + primeNumber);
             }
         }
         return index; // return -1 if pattern does not found
diff --git a/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java b/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java
index 4689dccf08fd..a8dc96e91998 100644
--- a/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java
@@ -6,12 +6,11 @@
 import org.junit.jupiter.params.provider.CsvSource;
 
 class RabinKarpAlgorithmTest {
-    RabinKarpAlgorithm RKA = new RabinKarpAlgorithm();
 
     @ParameterizedTest
     @CsvSource({"This is an example for rabin karp algorithmn, algorithmn, 101", "AAABBDDG, AAA, 137", "AAABBCCBB, BBCC, 101", "AAABBCCBB, BBCC, 131", "AAAABBBBCCC, CCC, 41", "ABCBCBCAAB, AADB, 293", "Algorithm The Algorithm, Algorithm, 101"})
     void RabinKarpAlgorithmTestExample(String txt, String pat, int q) {
-        int indexFromOurAlgorithm = RKA.search(pat, txt, q);
+        int indexFromOurAlgorithm = RabinKarpAlgorithm.search(pat, txt, q);
         int indexFromLinearSearch = txt.indexOf(pat);
         assertEquals(indexFromOurAlgorithm, indexFromLinearSearch);
     }

From a3a2d845d563a901946e052eeebba2f6e51e37d8 Mon Sep 17 00:00:00 2001
From: Appari Satya Barghav <36763910+satyabarghav@users.noreply.github.com>
Date: Wed, 4 Oct 2023 20:02:49 +0530
Subject: [PATCH 0033/1338] Made changes to the code to correct the Logic of
 Armstrong Number (#4619)

* Made changes to the code to correct the Logic of Armstrong Number

* Resolved the issues

* Trying to resolve the Linter error by changing Variable name

* Changed Variable Names : trying to resolve Clang error
---
 .../com/thealgorithms/maths/Armstrong.java    | 33 +++++++++++--------
 .../thealgorithms/maths/ArmstrongTest.java    |  8 +++--
 2 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Armstrong.java b/src/main/java/com/thealgorithms/maths/Armstrong.java
index dda8288a722f..526b31c3891f 100644
--- a/src/main/java/com/thealgorithms/maths/Armstrong.java
+++ b/src/main/java/com/thealgorithms/maths/Armstrong.java
@@ -1,29 +1,36 @@
 package com.thealgorithms.maths;
 
 /**
- * An Armstrong number is equal to the sum of the cubes of its digits. For
- * example, 370 is an Armstrong number because 3*3*3 + 7*7*7 + 0*0*0 = 370. An
- * Armstrong number is often called Narcissistic number.
+ * This class checks whether a given number is an Armstrong number or not.
+ * An Armstrong number is a number that is equal to the sum of its own digits,
+ * each raised to the power of the number of digits.
  *
- * @author Vivek
+ * For example, 370 is an Armstrong number because 3^3 + 7^3 + 0^3 = 370.
+ * 1634 is an Armstrong number because 1^4 + 6^4 + 3^4 + 4^4 = 1634.
+ * An Armstrong number is often called a Narcissistic number.
+ *
+ * @author satyabarghav
  */
 public class Armstrong {
 
     /**
-     * Checks whether a given number is an armstrong number or not.
+     * Checks whether a given number is an Armstrong number or not.
      *
-     * @param number number to check
-     * @return {@code true} if given number is armstrong number, {@code false}
-     * otherwise
+     * @param number the number to check
+     * @return {@code true} if the given number is an Armstrong number, {@code false} otherwise
      */
     public boolean isArmstrong(int number) {
         long sum = 0;
-        long number2 = number;
-        while (number2 > 0) {
-            long mod = number2 % 10;
-            sum += Math.pow(mod, 3);
-            number2 /= 10;
+        String temp = Integer.toString(number); // Convert the given number to a string
+        int power = temp.length(); // Extract the length of the number (number of digits)
+        long originalNumber = number;
+
+        while (originalNumber > 0) {
+            long digit = originalNumber % 10;
+            sum += Math.pow(digit, power); // The digit raised to the power of the number of digits and added to the sum.
+            originalNumber /= 10;
         }
+
         return sum == number;
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/ArmstrongTest.java b/src/test/java/com/thealgorithms/maths/ArmstrongTest.java
index 3b11b83de75f..e5d0d9eb3c43 100644
--- a/src/test/java/com/thealgorithms/maths/ArmstrongTest.java
+++ b/src/test/java/com/thealgorithms/maths/ArmstrongTest.java
@@ -5,8 +5,8 @@
 import org.junit.jupiter.api.Test;
 
 /**
- * @author Vivek
- * @since 15/03/22
+ * @author satyabarghav
+ * @since 4/10/2023
  */
 class ArmstrongTest {
 
@@ -17,7 +17,9 @@ void testIsArmstrong() {
         assertThat(armstrong.isArmstrong(1)).isTrue();
         assertThat(armstrong.isArmstrong(153)).isTrue();
         assertThat(armstrong.isArmstrong(371)).isTrue();
-        assertThat(armstrong.isArmstrong(1634)).isFalse();
+        assertThat(armstrong.isArmstrong(1634)).isTrue();
         assertThat(armstrong.isArmstrong(200)).isFalse();
+        assertThat(armstrong.isArmstrong(548834)).isTrue();
+        assertThat(armstrong.isArmstrong(9474)).isTrue();
     }
 }

From 06d6e2116bb1dd825262d6ca447f07eff1dca68d Mon Sep 17 00:00:00 2001
From: Aman <84791435+Aman28801@users.noreply.github.com>
Date: Thu, 5 Oct 2023 18:38:28 +0530
Subject: [PATCH 0034/1338] Update Readme.md (#4634)

---
 .../datastructures/graphs/README.md           | 78 ++++++++++---------
 1 file changed, 42 insertions(+), 36 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/README.md b/src/main/java/com/thealgorithms/datastructures/graphs/README.md
index 25e951ad9159..057adb46acf5 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/README.md
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/README.md
@@ -1,6 +1,5 @@
-## Graph
-
-Graph is a useful data structure for representing most of the real world problems involving a set of users/candidates/nodes and their relations. A Graph consists of two parameters :
+## Graphs
+Graph is a useful data structure for representing most of the real-world problems involving a set of users/candidates/nodes and their relations. A graph consists of two parameters:
 
 ```
 V = a set of vertices
@@ -9,59 +8,65 @@ E = a set of edges
 
 Each edge in `E` connects any two vertices from `V`. Based on the type of edge, graphs can be of two types:
 
-1. **Directed**: The edges are directed in nature which means that when there is an edge from node `A` to `B`, it does not imply that there is an edge from `B` to `A`.
-An example of directed edge graph the **follow** feature of social media. If you follow a celebrity, it doesn't imply that s/he follows you.
+1. **Directed**: The edges are directed in nature, which means that when there is an edge from node `A` to `B`, it does not imply that there is an edge from `B` to `A`. An example of a directed edge graph is the **follow** feature of social media. If you follow a celebrity, it doesn't imply that they follow you.
 
-2. **Undirected**: The edges don't have any direction. So if `A` and `B` are connected, we can assume that there is edge from both `A` to `B` and `B` to `A`.
-Example: Social media graph, where if two persons are friend, it implies that both are friend with each other.
+2. **Undirected**: The edges don't have any direction. So if `A` and `B` are connected, we can assume that there is an edge from both `A` to `B` and `B` to `A`. For example, in a social media graph, if two persons are friends, it implies that both are friends with each other.
 
 ### Components of a Graph
 
 **Vertices:** Vertices are the fundamental units of the graph. Sometimes, vertices are also known as vertex or nodes. Every node/vertex can be labeled or unlabelled.
-**Edges:** Edges are drawn or used to connect two nodes of the graph. It can be ordered pair of nodes in a directed graph. Edges can connect any two nodes in any possible way. There are no rules. Sometimes, edges are also known as arcs. Every edge can be labeled/unlabelled.
 
-Graphs are used to solve many real-life problems. Graphs are used to represent networks. The networks may include paths in a city or telephone network or circuit network. Graphs are also used in social networks like linkedIn, Facebook. For example, in Facebook, each person is represented with a vertex(or node). Each node is a structure and contains information like person id, name, gender, locale etc.
+**Edges:** Edges are used to connect two nodes of the graph. They can be an ordered pair of nodes in a directed graph. Edges can connect any two nodes in any possible way. There are no rules. Sometimes, edges are also known as arcs. Every edge can be labeled/unlabeled.
+
+Graphs are used to solve many real-life problems. Graphs are used to represent networks. The networks may include paths in a city, telephone network, or circuit network. Graphs are also used in social networks like LinkedIn, Facebook. For example, on Facebook, each person is represented with a vertex (or node). Each node is a structure and contains information like person id, name, gender, locale, etc.
 
-### Graph Representation:
+### Graph Representation
 
 Graph can be represented in the following ways:
 
 **Set Representation:** Set representation of a graph involves two sets: Set of vertices V = {V1, V2, V3, V4} and set of edges E = {{V1, V2}, {V2, V3}, {V3, V4}, {V4, V1}}. This representation is efficient for memory but does not allow parallel edges.
-**Sequential Representation:** This representation of a graph can be represented by means of matrices: Adjacency Matrix, Incidence matrix and Path matrix.
-**Adjacency Matrix:** This matrix includes information about the adjacent nodes. Here, aij = 1 if there is an edge from Vi to Vj otherwise 0. It is a matrix of order V×V.
-**Incidence Matrix:** This matrix includes information about the incidence of edges on the nodes. Here, aij = 1 if the jth edge Ej is incident on ith vertex Vi otherwise 0. It is a matrix of order V×E.
-**Path Matrix:** This matrix includes information about the simple path between two vertices. Here, Pij = 1 if there is a path from Vi to Vj otherwise 0. It is also called as reachability matrix of graph G.  
-**Linked Representation:** This representation gives the information about the nodes to which a specific node is connected i.e. adjacency lists. This representation gives the adjacency lists of the vertices with the help of array and linked lists. In the adjacency lists, the vertices which are connected with the specific vertex are arranged in the form of lists which is connected to that vertex.
 
+**Sequential Representation:** This representation of a graph can be represented by means of matrices: Adjacency Matrix, Incidence matrix, and Path matrix.
+
+**Adjacency Matrix:** This matrix includes information about the adjacent nodes. Here, aij = 1 if there is an edge from Vi to Vj; otherwise, it's 0. It is a matrix of order V×V.
+
+**Incidence Matrix:** This matrix includes information about the incidence of edges on the nodes. Here, aij = 1 if the jth edge Ej is incident on the ith vertex Vi; otherwise, it's 0. It is a matrix of order V×E.
+
+**Path Matrix:** This matrix includes information about the simple path between two vertices. Here, Pij = 1 if there is a path from Vi to Vj; otherwise, it's 0. It is also called the reachability matrix of graph G.
+
+**Linked Representation:** This representation gives information about the nodes to which a specific node is connected, i.e., adjacency lists. This representation gives the adjacency lists of the vertices with the help of arrays and linked lists. In the adjacency lists, the vertices connected to the specific vertex are arranged in the form of lists that are connected to that vertex.
 
-### Real-Time Applications of Graph:
-Graphs are used to represent flow of control in computers.
-Graphs are used in social networking sites where users act as nodes and connection between them acts as edges.
+### Real-Time Applications of Graph
+
+Graphs are used to represent the flow of control in computers.
+Graphs are used in social networking sites where users act as nodes, and connections between them act as edges.
 In an operating system, graphs are used as resource allocation graphs.
-Graphs are used in Google maps to find the shortest route.
-Graphs are also used in airlines system for effective route optimization. 
-In-state transition diagrams, the graph is used to represent their states and their transition.
+Graphs are used in Google Maps to find the shortest route.
+Graphs are also used in the airline system for effective route optimization.
+In state transition diagrams, the graph is used to represent states and their transitions.
 In transportation, graphs are used to find the shortest path.
 In circuits, graphs can be used to represent circuit points as nodes and wires as edges.
 Graphs are used in solving puzzles with only one solution, such as mazes.
-Graphs are used in computer networks for Peer to peer (P2P) applications.
-Graphs basically in the form of DAG(Directed acyclic graph) are used as alternative to blockchain for cryptocurrency. For example crypto like  IOTA, Nano are mainly based on DAG.
+Graphs are used in computer networks for Peer to Peer (P2P) applications.
+Graphs, basically in the form of DAG (Directed Acyclic Graph), are used as an alternative to blockchain for cryptocurrency. For example, cryptocurrencies like IOTA and Nano are mainly based on DAG.
+
+### Advantages of Graph
 
-### Advantages of Graph:
-By using graphs we can easily find the shortest path, neighbors of the nodes, and many more.
+Using graphs, we can easily find the shortest path, neighbors of the nodes, and many more.
 Graphs are used to implement algorithms like DFS and BFS.
-It is used to find minimum spanning tree which has many practical applications.
-It helps in organizing data.
-Because of its non-linear structure, helps in understanding complex problems and their visualization.
+They are used to find minimum spanning trees, which have many practical applications.
+Graphs help in organizing data.
+Because of their non-linear structure, graphs help in understanding complex problems and their visualization.
+
+### Disadvantages of Graph
 
-### Disadvantages of Graph:
-Graphs use lots of pointers which can be complex to handle.
-It can have large memory complexity.
-If the graph is represented with an adjacency matrix then it does not allow parallel edges and multiplication of the graph is also difficult. 
+Graphs use lots of pointers, which can be complex to handle.
+They can have large memory complexity.
+If the graph is represented with an adjacency matrix, then it does not allow parallel edges, and multiplication of the graph is also difficult.
 
 ### Representation
 
-1.  **Adjacency Lists**: Each node is represented as an entry and all the edges are represented as a list emerging from the corresponding node. So if vertex `1` has eadges to 2,3, and 6, the list corresponding to 1 will have 2,3 and 6 as entries. Consider the following graph.
+1. **Adjacency Lists**: Each node is represented as an entry, and all the edges are represented as a list emerging from the corresponding node. So, if vertex 1 has edges to 2, 3, and 6, the list corresponding to 1 will have 2, 3, and 6 as entries. Consider the following graph:
 
 ```
 0: 1-->2-->3
@@ -70,9 +75,10 @@ If the graph is represented with an adjacency matrix then it does not allow para
 3: 0-->4
 4: 3
 ```
-It means there are edges from 0 to 1, 2 and 3; from 1 to 0 and 2 and so on.
-2. **Adjacency Matrix**: The graph is represented as a matrix of size `|V| x |V|` and an entry 1 in cell `(i,j)` implies that there is an edge from i to j. 0 represents no edge.
-The mtrix for the above graph:
+
+It means there are edges from 0 to 1, 2, and 3; from 1 to 0 and 2, and so on.
+
+2. **Adjacency Matrix**: The graph is represented as a matrix of size |V| x |V|, and an entry 1 in cell (i, j) implies that there is an edge from i to j. 0 represents no edge. The matrix for the above graph:
 
 ```
    0 1 2 3 4

From 064ca8f59124eb3c792d2202ff12260e87e91552 Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Thu, 5 Oct 2023 22:01:27 +0200
Subject: [PATCH 0035/1338] cleanup `FindMinRecursion` (#4568)

* Create FindMinRecusionTest.java

* Update FindMinRecursion.java

* Update FindMinRecursion.java

* Update FindMinRecursion.java

* Rename FindMinRecusionTest.java to FindMinRecursionTest.java

* Update FindMinRecursionTest.java

* style: remove unused imports

---------

Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 .../thealgorithms/maths/FindMinRecursion.java | 41 ++++---------------
 .../maths/FindMinRecursionTest.java           | 28 +++++++++++++
 2 files changed, 36 insertions(+), 33 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/FindMinRecursionTest.java

diff --git a/src/main/java/com/thealgorithms/maths/FindMinRecursion.java b/src/main/java/com/thealgorithms/maths/FindMinRecursion.java
index 71d7795b7e47..6ffe034ee40f 100644
--- a/src/main/java/com/thealgorithms/maths/FindMinRecursion.java
+++ b/src/main/java/com/thealgorithms/maths/FindMinRecursion.java
@@ -1,38 +1,13 @@
 package com.thealgorithms.maths;
 
-import java.util.Arrays;
-import java.util.Random;
+public final class FindMinRecursion {
 
-public class FindMinRecursion {
-
-    /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        Random rand = new Random();
-
-        /* rand size */
-        int size = rand.nextInt(100) + 1;
-        int[] array = new int[size];
-
-        /* init array with rand numbers */
-        for (int i = 0; i < size; i++) {
-            array[i] = rand.nextInt() % 100;
-        }
-
-        assert min(array, 0, array.length - 1) == Arrays.stream(array).min().getAsInt();
-        assert min(array) == Arrays.stream(array).min().getAsInt();
+    private FindMinRecursion() {
     }
-
-    /**
-     * Get min of array using divide and conquer algorithm
-     *
-     * @param array contains elements
-     * @param low the index of the first element
-     * @param high the index of the last element
-     * @return min of {@code array}
-     */
-    public static int min(int[] array, int low, int high) {
+    public static int min(final int[] array, final int low, final int high) {
+        if (array.length == 0) {
+            throw new IllegalArgumentException("array must be non-empty.");
+        }
         if (low == high) {
             return array[low]; // or array[high]
         }
@@ -52,7 +27,7 @@ public static int min(int[] array, int low, int high) {
      * @param len length of given array
      * @return min value of {@code array}
      */
-    public static int min(int[] array) {
-        return array.length == 1 ? array[0] : min(array, 0, array.length);
+    public static int min(final int[] array) {
+        return min(array, 0, array.length - 1);
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/FindMinRecursionTest.java b/src/test/java/com/thealgorithms/maths/FindMinRecursionTest.java
new file mode 100644
index 000000000000..3c36702b881d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/FindMinRecursionTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class FindMinRecursionTest {
+
+    @ParameterizedTest
+    @MethodSource("inputStream")
+    void numberTests(int expected, int[] input) {
+        Assertions.assertEquals(expected, FindMinRecursion.min(input));
+    }
+
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of(5, new int[] {5, 5, 5, 5, 5}), Arguments.of(-1, new int[] {-1, 0}), Arguments.of(-10, new int[] {-10, -9, -8, -7, -6, -5, -4, -3, -2, -1}), Arguments.of(-4, new int[] {3, -2, 3, 9, -4, -4, 8}), Arguments.of(3, new int[] {3}));
+    }
+
+    @Test
+    public void testFindMaxThrowsExceptionForEmptyInput() {
+        assertThrows(IllegalArgumentException.class, () -> FindMinRecursion.min(new int[] {}));
+    }
+}

From 081f308b9d7c2a22935eff6f8b7b18258111a3d3 Mon Sep 17 00:00:00 2001
From: Suchi Bansal <suchibansal2007@gmail.com>
Date: Fri, 6 Oct 2023 23:45:27 +0530
Subject: [PATCH 0036/1338] Add `ReverseWordsInString` (#4456)

* return a string of the words in reverse order concatenated by a single space.

Input: s = "the sky is blue"
Output: "blue is sky the"

* return a string of the words in reverse order concatenated by a single space.

Input: s = "the sky is blue"
Output: "blue is sky the"

* space reduce

* removed main method

* added test cases

* formatting fix

* formatting fix

* worked on pr reviews

* formatting fix

* private constructor added

* added test case for when string contains white space

* simplified method

* fix issue

* formatting issues fix

* fixed issue

* code refactor

* documented method

* worked on pr comments

* docs: add missing space

* tests: express as `ParameterizedTest`

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Co-authored-by: vil02 <vil02@o2.pl>
---
 .../strings/ReverseWordsInString.java         | 22 +++++++++++++++++++
 .../strings/ReverseWordsInStringTest.java     | 20 +++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/ReverseWordsInString.java
 create mode 100644 src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java

diff --git a/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java b/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java
new file mode 100644
index 000000000000..5f9d27b4e9e2
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.strings;
+
+import java.util.Arrays;
+import java.util.Collections;
+
+public final class ReverseWordsInString {
+
+    private ReverseWordsInString() {
+    }
+
+    /**
+     * @brief Reverses words in the input string
+     * @param s the input string
+     * @return A string created by reversing the order of the words in {@code s}
+     */
+
+    public static String reverseWordsInString(final String s) {
+        var words = s.trim().split("\\s+");
+        Collections.reverse(Arrays.asList(words));
+        return String.join(" ", words);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java b/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java
new file mode 100644
index 000000000000..44e397459349
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java
@@ -0,0 +1,20 @@
+package com.thealgorithms.strings;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class ReverseWordsInStringTest {
+    @ParameterizedTest
+    @MethodSource("inputStream")
+    void numberTests(String expected, String input) {
+        Assertions.assertEquals(expected, ReverseWordsInString.reverseWordsInString(input));
+    }
+
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of("blue is Sky", "Sky is blue"), Arguments.of("blue is Sky", "Sky \n is \t \n  blue "), Arguments.of("", ""), Arguments.of("", "    "), Arguments.of("", "\t"));
+    }
+}

From aaa2b26ed19477c4e8b8198782c1ee6c560bf8b3 Mon Sep 17 00:00:00 2001
From: Piyush Pagar <89297062+PiyushPagar@users.noreply.github.com>
Date: Sat, 7 Oct 2023 18:57:46 +0530
Subject: [PATCH 0037/1338] Issue #4706 Solved (#4707)

Import Package into the RecursiveBinarySearchTest and RecursiveBinarySearch

Co-authored-by: PiyushPagar1 <piyus.p@ergobite.com>
---
 .../java/com/thealgorithms/searches/RecursiveBinarySearch.java  | 2 +-
 .../com/thealgorithms/searches/RecursiveBinarySearchTest.java   | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
index 8a02b30a9f0e..0a84aa1d64ce 100644
--- a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
@@ -2,7 +2,7 @@
 // Created:- 1/10/2023
 // File Name should be RecursiveBinarySearch.java
 // Explanation:- https://www.tutorialspoint.com/java-program-for-binary-search-recursive
-
+package com.thealgorithms.searches;
 import java.util.*;
 
 // Create a SearchAlgorithm class with a generic type
diff --git a/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java
index 3b2cdead1c6b..4144efa5e89b 100644
--- a/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java
@@ -1,6 +1,7 @@
 // Created by Pronay Debnath
 // Date:- 1/10/2023
 // Test file updated with JUnit tests
+package com.thealgorithms.searches;
 
 import static org.junit.jupiter.api.Assertions.*;
 

From 7f9555bd947fcb2292514642655810dd59d02c87 Mon Sep 17 00:00:00 2001
From: Anuj Rathour <anuj.rathour9335@gmail.com>
Date: Sat, 7 Oct 2023 23:07:57 +0530
Subject: [PATCH 0038/1338] Update stack readme.md (#4678)

---
 .../datastructures/stacks/README.md           | 20 ++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/README.md b/src/main/java/com/thealgorithms/datastructures/stacks/README.md
index 69fc3a990383..55c3ffd7de64 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/README.md
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/README.md
@@ -1,10 +1,14 @@
 # STACK
 
-Stack is an ADT (abstract data type) that acts like a list of objects but there is a difference.
+- Stack is an ADT (abstract data type) that is a collection of elements where items are added and removed from the end, known as the "top" of the stack.
 
-Stack works on the principle of _LIFO_ (Last In First Out), it means that the last item added to the stack will be the first item to be removed.
+- Stack works on the principle of _LIFO_ (Last In First Out), it means that the last item added to the stack will be the first item to be removed.
 
-Stack is based on two methods (functions)-
+## Declaration
+ `Stack<Obj> stack=new Stack<Obj>();`
+
+# Functionalities
+Stack is based on two functions (methods)-
 
 ## push(element)
 
@@ -29,3 +33,13 @@ It removes the last element (i.e. top of stack) from stack.
 For example: If we have `1, 3, 5 , 9` in stack, and we call pop(),
 
 the function will return `9` and the stack will change to `1, 3, 5`.
+
+# Real Life Applications 
+  - `Undo mechanisms:`
+     Many software applications use stacks to implement an "undo" feature.
+
+  - `Browser history:`
+    The "back" button in a web browser is implemented using a stack, allowing users to navigate through previously visited pages.
+
+  - `Function calls and recursion:` 
+    The computer's call stack keeps track of function calls, allowing programs to remember where to return after a function finishes execution.

From 06aa834fa6991a15e36ef0ca4c44f4522cbdb347 Mon Sep 17 00:00:00 2001
From: Aman <84791435+Aman28801@users.noreply.github.com>
Date: Sun, 8 Oct 2023 13:17:35 +0530
Subject: [PATCH 0039/1338] Enhance queue README.md (#4710)

---
 .../datastructures/queues/README.md           | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/README.md b/src/main/java/com/thealgorithms/datastructures/queues/README.md
index e110686acae9..ca5e2972f8c5 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/README.md
+++ b/src/main/java/com/thealgorithms/datastructures/queues/README.md
@@ -7,6 +7,29 @@
 - It supports all methods of Collection interface including insertion, deletion etc.
 - LinkedList, ArrayBlockingQueue and PriorityQueue are the most commonly used implementations.
 
+
+## Types Of Queue:-
+
+- **FIFO Queue (First-In-First-Out):** This is the most common type of queue where the first item added is the first one to be removed. It follows a strict order of insertion and removal.
+
+
+- **Priority Queue:** Elements in this queue are assigned priorities, and the item with the highest priority is dequeued first. It doesn't strictly follow the FIFO order.
+
+
+- **Double-ended Queue (Deque):** A queue that allows elements to be added and removed from both ends. It can function as both a FIFO queue and a LIFO stack.
+
+
+- **Circular Queue:** In this type, the last element is connected to the first element, forming a circular structure. It's often used for tasks like managing memory buffers.
+
+
+- **Blocking Queue:** Designed for multithreaded applications, it provides thread-safety and blocking operations. Threads can wait until an element is available or space is free.
+
+
+- **Priority Blocking Queue:** Similar to a priority queue but thread-safe, it allows multiple threads to access and modify the queue concurrently while maintaining priority.
+
+
+- **Delay Queue:** Used for scheduling tasks to run after a specific delay or at a certain time. Elements are removed from the queue when their delay expires.
+
 ## Declaration
 
 `Queue<Obj> queue = new PriorityQueue<Obj> ();` 
@@ -21,3 +44,5 @@
 |Rear|Gets the last item from the queue|
 
 
+
+

From 8200a791a28002ca23ac70c73d4c83399beab831 Mon Sep 17 00:00:00 2001
From: Prabhat-Kumar <prabhatkumarverma42@gmail.com>
Date: Sun, 8 Oct 2023 18:46:06 +0530
Subject: [PATCH 0040/1338] Add `AhoCorasick` (#4465)

* Added code to find Articulation Points and Bridges

* tried to solve clang-formant test

* removed new line at EOF to get lint to pass

* feature: Added Ahocorasick Algorithm

* fixed lint using clang-format

* removed datastructures/graphs/ArticulationPointsAndBridge.java from this branch

* removed main, since test-file is added. Also modified and renamed few functions.

* Added test-file for AhoCorasick Algorithm

* Modified some comments in test-file

* Modified some comments in AhoCorasick.java

* lint fix

* added few more test cases

* Modified some comments

* Change all class fields to private, added initializeSuffixLinksForChildNodesOfTheRoot() method, hashmap string search position (also has previous index based search), removed java.util.*

* Added Missing Test-Cases and more

* minor text changes

* added direct test check i.e. defining a variable expected and just checking if res and expected are equal.

* Created New Class Trie, merged 'buildTrie and buildSuffixAndOutputLinks' with 'Trie constructor'. Merged setUpStartPoints with searchIn. Now AhoCorasick contains -> inner class: Trie, Node. Methods: search and convert. Trie has -> Methods : constructor and searchIn

* Updated TestFile according to the updated AhoCorasick Class. Added Few more test cases

* updated - broken down constructor to relavent parts, made string final, made res local to searchIn(), doxygen-like style

* lint fix clang

* Updated Tests Files

* Added final field to Node class setters and Trie Constructor arguments, removed getTrieRoot() and some unnecessory comments, renamed [old -> new]: res -> positionByStringIndexValue, removed if condition from setupStartPoints()

* updated test file

* lint fix clang

* minor chage - 'removed a comment'

* added final fields to some arguments, class and variables, added a method initializePositionByStringIndexValue()

* updated to remove * inclusion and added the required modules only

* Implemented a new class PatternPositionRecorder to wrap up the position recording in searchIn()

* Added final fields to PatternPositionRecorder Class

* style: mark default constructor of `AhoCorasick` as `private`

* style: remoce redundant `public`

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../thealgorithms/strings/AhoCorasick.java    | 249 ++++++++++++++++++
 .../strings/AhoCorasickTest.java              | 120 +++++++++
 2 files changed, 369 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/AhoCorasick.java
 create mode 100644 src/test/java/com/thealgorithms/strings/AhoCorasickTest.java

diff --git a/src/main/java/com/thealgorithms/strings/AhoCorasick.java b/src/main/java/com/thealgorithms/strings/AhoCorasick.java
new file mode 100644
index 000000000000..6381830cb0bc
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/AhoCorasick.java
@@ -0,0 +1,249 @@
+/*
+ * Aho-Corasick String Matching Algorithm Implementation
+ *
+ * This code implements the Aho-Corasick algorithm, which is used for efficient
+ * string matching in a given text. It can find multiple patterns simultaneously
+ * and records their positions in the text.
+ *
+ * Author: Prabhat-Kumar-42
+ * GitHub: https://github.com/Prabhat-Kumar-42
+ */
+
+package com.thealgorithms.strings;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.Queue;
+
+public final class AhoCorasick {
+    private AhoCorasick() {
+    }
+
+    // Trie Node Class
+    private static class Node {
+        // Represents a character in the trie
+        private HashMap<Character, Node> child = new HashMap<>(); // Child nodes of the current node
+        private Node suffixLink; // Suffix link to another node in the trie
+        private Node outputLink; // Output link to another node in the trie
+        private int patternInd; // Index of the pattern that ends at this node
+
+        Node() {
+            this.suffixLink = null;
+            this.outputLink = null;
+            this.patternInd = -1;
+        }
+
+        public HashMap<Character, Node> getChild() {
+            return child;
+        }
+
+        public Node getSuffixLink() {
+            return suffixLink;
+        }
+
+        public void setSuffixLink(final Node suffixLink) {
+            this.suffixLink = suffixLink;
+        }
+
+        public Node getOutputLink() {
+            return outputLink;
+        }
+
+        public void setOutputLink(final Node outputLink) {
+            this.outputLink = outputLink;
+        }
+
+        public int getPatternInd() {
+            return patternInd;
+        }
+
+        public void setPatternInd(final int patternInd) {
+            this.patternInd = patternInd;
+        }
+    }
+
+    // Trie Class
+    public static class Trie {
+
+        private Node root = null; // Root node of the trie
+        private final String[] patterns; // patterns according to which Trie is constructed
+
+        public Trie(final String[] patterns) {
+            root = new Node(); // Initialize the root of the trie
+            this.patterns = patterns;
+            buildTrie();
+            buildSuffixAndOutputLinks();
+        }
+
+        // builds AhoCorasick Trie
+        private void buildTrie() {
+
+            // Loop through each input pattern and building Trie
+            for (int i = 0; i < patterns.length; i++) {
+                Node curr = root; // Start at the root of the trie for each pattern
+
+                // Loop through each character in the current pattern
+                for (int j = 0; j < patterns[i].length(); j++) {
+                    char c = patterns[i].charAt(j); // Get the current character
+
+                    // Check if the current node has a child for the current character
+                    if (curr.getChild().containsKey(c)) {
+                        curr = curr.getChild().get(c); // Update the current node to the child node
+                    } else {
+                        // If no child node exists, create a new one and add it to the current node's children
+                        Node nn = new Node();
+                        curr.getChild().put(c, nn);
+                        curr = nn; // Update the current node to the new child node
+                    }
+                }
+                curr.setPatternInd(i); // Store the index of the pattern in the current leaf node
+            }
+        }
+
+        private void initializeSuffixLinksForChildNodesOfTheRoot(Queue<Node> q) {
+            for (char rc : root.getChild().keySet()) {
+                Node childNode = root.getChild().get(rc);
+                q.add(childNode); // Add child node to the queue
+                childNode.setSuffixLink(root); // Set suffix link to the root
+            }
+        }
+
+        private void buildSuffixAndOutputLinks() {
+            root.setSuffixLink(root); // Initialize the suffix link of the root to itself
+            Queue<Node> q = new LinkedList<>(); // Initialize a queue for BFS traversal
+
+            initializeSuffixLinksForChildNodesOfTheRoot(q);
+
+            while (!q.isEmpty()) {
+                Node currentState = q.poll(); // Get the current node for processing
+
+                // Iterate through child nodes of the current node
+                for (char cc : currentState.getChild().keySet()) {
+                    Node currentChild = currentState.getChild().get(cc); // Get the child node
+                    Node parentSuffix = currentState.getSuffixLink(); // Get the parent's suffix link
+
+                    // Calculate the suffix link for the child based on the parent's suffix link
+                    while (!parentSuffix.getChild().containsKey(cc) && parentSuffix != root) {
+                        parentSuffix = parentSuffix.getSuffixLink();
+                    }
+
+                    // Set the calculated suffix link or default to root
+                    if (parentSuffix.getChild().containsKey(cc)) {
+                        currentChild.setSuffixLink(parentSuffix.getChild().get(cc));
+                    } else {
+                        currentChild.setSuffixLink(root);
+                    }
+
+                    q.add(currentChild); // Add the child node to the queue for further processing
+                }
+
+                // Establish output links for nodes to efficiently identify patterns within patterns
+                if (currentState.getSuffixLink().getPatternInd() >= 0) {
+                    currentState.setOutputLink(currentState.getSuffixLink());
+                } else {
+                    currentState.setOutputLink(currentState.getSuffixLink().getOutputLink());
+                }
+            }
+        }
+
+        private ArrayList<ArrayList<Integer>> initializePositionByStringIndexValue() {
+            ArrayList<ArrayList<Integer>> positionByStringIndexValue = new ArrayList<>(patterns.length); // Stores positions where patterns are found in the text
+            for (int i = 0; i < patterns.length; i++) {
+                positionByStringIndexValue.add(new ArrayList<Integer>());
+            }
+            return positionByStringIndexValue;
+        }
+
+        // Searches for patterns in the input text and records their positions
+        public ArrayList<ArrayList<Integer>> searchIn(final String text) {
+            var positionByStringIndexValue = initializePositionByStringIndexValue(); // Initialize a list to store positions of the current pattern
+            Node parent = root; // Start searching from the root node
+
+            PatternPositionRecorder positionRecorder = new PatternPositionRecorder(positionByStringIndexValue);
+
+            for (int i = 0; i < text.length(); i++) {
+                char ch = text.charAt(i); // Get the current character in the text
+
+                // Check if the current node has a child for the current character
+                if (parent.getChild().containsKey(ch)) {
+                    parent = parent.getChild().get(ch); // Update the current node to the child node
+                    positionRecorder.recordPatternPositions(parent, i); // Use the method in PatternPositionRecorder to record positions
+                } else {
+                    // If no child node exists for the character, backtrack using suffix links
+                    while (parent != root && !parent.getChild().containsKey(ch)) {
+                        parent = parent.getSuffixLink();
+                    }
+                    if (parent.getChild().containsKey(ch)) {
+                        i--; // Decrement i to reprocess the same character
+                    }
+                }
+            }
+
+            setUpStartPoints(positionByStringIndexValue);
+            return positionByStringIndexValue;
+        }
+
+        // by default positionByStringIndexValue contains end-points. This function converts those
+        // endpoints to start points
+        private void setUpStartPoints(ArrayList<ArrayList<Integer>> positionByStringIndexValue) {
+            for (int i = 0; i < patterns.length; i++) {
+                for (int j = 0; j < positionByStringIndexValue.get(i).size(); j++) {
+                    int endpoint = positionByStringIndexValue.get(i).get(j);
+                    positionByStringIndexValue.get(i).set(j, endpoint - patterns[i].length() + 1);
+                }
+            }
+        }
+    }
+
+    // Class to handle pattern position recording
+    private static class PatternPositionRecorder {
+        private ArrayList<ArrayList<Integer>> positionByStringIndexValue;
+
+        // Constructor to initialize the recorder with the position list
+        PatternPositionRecorder(final ArrayList<ArrayList<Integer>> positionByStringIndexValue) {
+            this.positionByStringIndexValue = positionByStringIndexValue;
+        }
+
+        /**
+         * Records positions for a pattern when it's found in the input text and follows
+         * output links to record positions of other patterns.
+         *
+         * @param parent The current node representing a character in the pattern trie.
+         * @param currentPosition      The current position in the input text.
+         */
+        public void recordPatternPositions(final Node parent, final int currentPosition) {
+            // Check if the current node represents the end of a pattern
+            if (parent.getPatternInd() > -1) {
+                // Add the current position to the list of positions for the found pattern
+                positionByStringIndexValue.get(parent.getPatternInd()).add(currentPosition);
+            }
+
+            Node outputLink = parent.getOutputLink();
+            // Follow output links to find and record positions of other patterns
+            while (outputLink != null) {
+                // Add the current position to the list of positions for the pattern linked by outputLink
+                positionByStringIndexValue.get(outputLink.getPatternInd()).add(currentPosition);
+                outputLink = outputLink.getOutputLink();
+            }
+        }
+    }
+    // method to search for patterns in text
+    public static Map<String, ArrayList<Integer>> search(final String text, final String[] patterns) {
+        final var trie = new Trie(patterns);
+        final var positionByStringIndexValue = trie.searchIn(text);
+        return convert(positionByStringIndexValue, patterns);
+    }
+
+    // method for converting results to a map
+    private static Map<String, ArrayList<Integer>> convert(final ArrayList<ArrayList<Integer>> positionByStringIndexValue, final String[] patterns) {
+        Map<String, ArrayList<Integer>> positionByString = new HashMap<>();
+        for (int i = 0; i < patterns.length; i++) {
+            String pattern = patterns[i];
+            ArrayList<Integer> positions = positionByStringIndexValue.get(i);
+            positionByString.put(pattern, new ArrayList<>(positions));
+        }
+        return positionByString;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java b/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java
new file mode 100644
index 000000000000..caaca561143f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java
@@ -0,0 +1,120 @@
+/*
+ * Tests For Aho-Corasick String Matching Algorithm
+ *
+ *            Author: Prabhat-Kumar-42
+ *    GitHub: https://github.com/Prabhat-Kumar-42
+ */
+
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Map;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/**
+ * This class contains test cases for the Aho-Corasick String Matching Algorithm.
+ * The Aho-Corasick algorithm is used to efficiently find all occurrences of multiple
+ * patterns in a given text.
+ */
+class AhoCorasickTest {
+    private String[] patterns; // The array of patterns to search for
+    private String text; // The input text to search within
+
+    /**
+     * This method sets up the test environment before each test case.
+     * It initializes the patterns and text to be used for testing.
+     */
+    @BeforeEach
+    void setUp() {
+        patterns = new String[] {"ACC", "ATC", "CAT", "GCG", "C", "T"};
+        text = "GCATCG";
+    }
+
+    /**
+     * Test searching for multiple patterns in the input text.
+     * The expected results are defined for each pattern.
+     */
+    @Test
+    void testSearch() {
+        // Define the expected results for each pattern
+        final var expected = Map.of("ACC", new ArrayList<>(Arrays.asList()), "ATC", new ArrayList<>(Arrays.asList(2)), "CAT", new ArrayList<>(Arrays.asList(1)), "GCG", new ArrayList<>(Arrays.asList()), "C", new ArrayList<>(Arrays.asList(1, 4)), "T", new ArrayList<>(Arrays.asList(3)));
+        assertEquals(expected, AhoCorasick.search(text, patterns));
+    }
+
+    /**
+     * Test searching with an empty pattern array.
+     * The result should be an empty map.
+     */
+    @Test
+    void testEmptyPatterns() {
+        // Define an empty pattern array
+        final var emptyPatterns = new String[] {};
+        assertTrue(AhoCorasick.search(text, emptyPatterns).isEmpty());
+    }
+
+    /**
+     * Test searching for patterns that are not present in the input text.
+     * The result should be an empty list for each pattern.
+     */
+    @Test
+    void testPatternNotFound() {
+        // Define patterns that are not present in the text
+        final var searchPatterns = new String[] {"XYZ", "123"};
+        final var expected = Map.of("XYZ", new ArrayList<Integer>(), "123", new ArrayList<Integer>());
+        assertEquals(expected, AhoCorasick.search(text, searchPatterns));
+    }
+
+    /**
+     * Test searching for patterns that start at the beginning of the input text.
+     * The expected position for each pattern is 0.
+     */
+    @Test
+    void testPatternAtBeginning() {
+        // Define patterns that start at the beginning of the text
+        final var searchPatterns = new String[] {"GC", "GCA", "GCAT"};
+        final var expected = Map.of("GC", new ArrayList<Integer>(Arrays.asList(0)), "GCA", new ArrayList<Integer>(Arrays.asList(0)), "GCAT", new ArrayList<Integer>(Arrays.asList(0)));
+        assertEquals(expected, AhoCorasick.search(text, searchPatterns));
+    }
+
+    /**
+     * Test searching for patterns that end at the end of the input text.
+     * The expected positions are 4, 3, and 2 for the patterns.
+     */
+    @Test
+    void testPatternAtEnd() {
+        // Define patterns that end at the end of the text
+        final var searchPatterns = new String[] {"CG", "TCG", "ATCG"};
+        final var expected = Map.of("CG", new ArrayList<Integer>(Arrays.asList(4)), "TCG", new ArrayList<Integer>(Arrays.asList(3)), "ATCG", new ArrayList<Integer>(Arrays.asList(2)));
+        assertEquals(expected, AhoCorasick.search(text, searchPatterns));
+    }
+
+    /**
+     * Test searching for patterns with multiple occurrences in the input text.
+     * The expected sizes are 1 and 1, and the expected positions are 2 and 3
+     * for the patterns "AT" and "T" respectively.
+     */
+    @Test
+    void testMultipleOccurrencesOfPattern() {
+        // Define patterns with multiple occurrences in the text
+        final var searchPatterns = new String[] {"AT", "T"};
+        final var expected = Map.of("AT", new ArrayList<Integer>(Arrays.asList(2)), "T", new ArrayList<Integer>(Arrays.asList(3)));
+        assertEquals(expected, AhoCorasick.search(text, searchPatterns));
+    }
+
+    /**
+     * Test searching for patterns in a case-insensitive manner.
+     * The search should consider patterns regardless of their case.
+     */
+    @Test
+    void testCaseInsensitiveSearch() {
+        // Define patterns with different cases
+        final var searchPatterns = new String[] {"gca", "aTc", "C"};
+        final var expected = Map.of("gca", new ArrayList<Integer>(), "aTc", new ArrayList<Integer>(), "C", new ArrayList<Integer>(Arrays.asList(1, 4)));
+        assertEquals(expected, AhoCorasick.search(text, searchPatterns));
+    }
+}

From facc62a81afd1ff8a5f9cb3a78e505ee2e6515c1 Mon Sep 17 00:00:00 2001
From: Arin <136636751+asapekia@users.noreply.github.com>
Date: Mon, 9 Oct 2023 00:36:13 +0530
Subject: [PATCH 0041/1338] adding formatting steps in pull request template
 (#4606)

* adding formatting steps in contribution.md

* adding format to pull request template

* made format instruction shorter

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .github/pull_request_template.md | 1 +
 CONTRIBUTING.md                  | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index ce1d87a2c62e..d9cc4c3c35c5 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -13,3 +13,4 @@ In order to reduce the number of notifications sent to the maintainers, please:
 - [ ] All filenames are in PascalCase.
 - [ ] All functions and variable names follow Java naming conventions.
 - [ ] All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
+- [ ] All new code is formatted with `clang-format -i --style=file path/to/your/file.java`
\ No newline at end of file
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index dcc86c50360d..f2f8dd9ffdea 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -28,4 +28,4 @@ NOTE: *Please avoid opening issues asking to be "assigned" to a particular algor
 
 - Ask any question about how to use the repository in the [TheAlgorithms room in GITTER](https://gitter.im/TheAlgorithms/community?source=orgpage#) or [open a new issue](https://github.com/TheAlgorithms/Java/issues/new)
 
-:+1::tada: That's all you need to know about the process now it's your turn to help us improve the repository, thank you again! :+1::tada:
+:+1::tada: That's all you need to know about the process now it's your turn to help us improve the repository, thank you again! :+1::tada:
\ No newline at end of file

From c6a22de12f820f3f6f92a60515acce979ff16162 Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Mon, 9 Oct 2023 17:17:02 +0200
Subject: [PATCH 0042/1338] Add `MinValueTest` and remove `main` from
 `MinValue` (#4713)

* Update MinValue.java

* Create MinValueTest.java

* Revert "Create MinValueTest.java"

* Create MinValueTest.java

* Update MinValueTest.java

* Update MinValueTest.java

* Update MinValue.java

* Update src/test/java/com/thealgorithms/maths/MinValueTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/maths/MinValueTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/MinValue.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/maths/MinValue.java     | 20 ++-----------------
 .../com/thealgorithms/maths/MinValueTest.java | 14 +++++++++++++
 2 files changed, 16 insertions(+), 18 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/MinValueTest.java

diff --git a/src/main/java/com/thealgorithms/maths/MinValue.java b/src/main/java/com/thealgorithms/maths/MinValue.java
index badc6c7cfb69..88e28e8816c6 100644
--- a/src/main/java/com/thealgorithms/maths/MinValue.java
+++ b/src/main/java/com/thealgorithms/maths/MinValue.java
@@ -1,24 +1,8 @@
 package com.thealgorithms.maths;
 
-import java.util.Random;
-
-public class MinValue {
-
-    /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        Random rand = new Random();
-
-        /* test 100 times using rand numbers */
-        for (int i = 1; i <= 100; ++i) {
-            /* generate number from -50 to 49 */
-            int a = rand.nextInt(100) - 50;
-            int b = rand.nextInt(100) - 50;
-            assert min(a, b) == Math.min(a, b);
-        }
+public final class MinValue {
+    private MinValue() {
     }
-
     /**
      * Returns the smaller of two {@code int} values. That is, the result the
      * argument closer to the value of {@link Integer#MIN_VALUE}. If the
diff --git a/src/test/java/com/thealgorithms/maths/MinValueTest.java b/src/test/java/com/thealgorithms/maths/MinValueTest.java
new file mode 100644
index 000000000000..beb0ccb1a571
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/MinValueTest.java
@@ -0,0 +1,14 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class MinValueTest {
+    @Test
+    public void minTest() {
+        assertEquals(-1, MinValue.min(-1, 3));
+        assertEquals(2, MinValue.min(3, 2));
+        assertEquals(5, MinValue.min(5, 5));
+    }
+}

From ced96786990696589b86cc9fa3d8bc098510dc00 Mon Sep 17 00:00:00 2001
From: Anuj Rathour <anuj.rathour9335@gmail.com>
Date: Mon, 9 Oct 2023 21:03:34 +0530
Subject: [PATCH 0043/1338] Update queue readme (#4721)

---
 .../datastructures/queues/README.md           | 57 ++++++++++++++++---
 1 file changed, 49 insertions(+), 8 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/README.md b/src/main/java/com/thealgorithms/datastructures/queues/README.md
index ca5e2972f8c5..ef1b89b5c9a4 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/README.md
+++ b/src/main/java/com/thealgorithms/datastructures/queues/README.md
@@ -31,17 +31,58 @@
 - **Delay Queue:** Used for scheduling tasks to run after a specific delay or at a certain time. Elements are removed from the queue when their delay expires.
 
 ## Declaration
-
-`Queue<Obj> queue = new PriorityQueue<Obj> ();` 
+`Queue<Obj> queue = new PriorityQueue<Obj>();`
 
 ## Important operations
 
-| Operations | Description |
-| ----------- | ----------- |
-|Enqueue|Adds an item to the queue|
-|Dequeue|Removes an item from the queue|
-|Front|Gets the front item from the queue|
-|Rear|Gets the last item from the queue|
+| Operations | Description |Time Complexity
+| ----------- | ----------- |-----------
+|Enqueue|Adds an item to the queue|O(1)
+|Dequeue|Removes an item from the queue|O(1)
+|Front|Gets the front item from the queue|O(1)
+|Rear|Gets the last item from the queue|O(n)
+
+## Enqueue
+ It adds  an item to the rear of the queue.
+
+ For example: If we have `1, 2, 3, 4, 5` in queue, and if we call Enqueue(8),
+
+`8` will be added to last index of queue -> `1, 2, 3, 4, 5, 8`.
+## Dequeue
+ 
+ It removes an item to the front of the queue.
+ 
+ For example: If we have `1, 2, 3, 4, 5` in queue, and we call Dequeue(),
+
+`1` will be removed from front of queue and returned -> `2, 3, 4, 5`.
+
+## Front 
+  It returns an item to the front of the queue.
+
+For example: If we have `1, 2, 3, 5` in queue, and we call Front(),
+
+`1` will be returned (without removing it from the queue).
+
+## Rear
+  It returns an item to the rear of the queue.
+  
+  For example: If we have `1, 2, 3, 5` in queue, and we call Rear(),
+
+`5` will be returned (without removing it from the queue).
+
+# Real Life Applications
+`Task Scheduling in Operating Systems:`
+
+Processes in a multitasking system are often scheduled using queues. For example, the ready queue contains processes ready to be executed.
+
+`Multi-threaded Programming:`
+
+Queues are often used to facilitate communication and synchronization between different threads.
+
+`Breadth-First Search (BFS) in Graphs:`
+
+Queues are used in algorithms like BFS to explore a graph level by level.
+
 
 
 

From 17fe4298b699ff4cb6282a5e1e0edcd7541f6735 Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Tue, 10 Oct 2023 21:27:23 +0200
Subject: [PATCH 0044/1338] Add MaxValueTest and remove main from MaxValue
 (#4756)

* Create MaxValueTest.java

* Update MaxValue.java
---
 .../com/thealgorithms/maths/MaxValue.java     | 20 ++-----------------
 .../com/thealgorithms/maths/MaxValueTest.java | 14 +++++++++++++
 2 files changed, 16 insertions(+), 18 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/MaxValueTest.java

diff --git a/src/main/java/com/thealgorithms/maths/MaxValue.java b/src/main/java/com/thealgorithms/maths/MaxValue.java
index a4603533a2df..d88291060f51 100644
--- a/src/main/java/com/thealgorithms/maths/MaxValue.java
+++ b/src/main/java/com/thealgorithms/maths/MaxValue.java
@@ -1,24 +1,8 @@
 package com.thealgorithms.maths;
 
-import java.util.Random;
-
-public class MaxValue {
-
-    /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        Random rand = new Random();
-
-        /* test 100 times using rand numbers */
-        for (int i = 1; i <= 100; ++i) {
-            /* generate number from -50 to 49 */
-            int a = rand.nextInt(100) - 50;
-            int b = rand.nextInt(100) - 50;
-            assert max(a, b) == Math.max(a, b);
-        }
+public final class MaxValue {
+    private MaxValue() {
     }
-
     /**
      * Returns the greater of two {@code int} values. That is, the result is the
      * argument closer to the value of {@link Integer#MAX_VALUE}. If the
diff --git a/src/test/java/com/thealgorithms/maths/MaxValueTest.java b/src/test/java/com/thealgorithms/maths/MaxValueTest.java
new file mode 100644
index 000000000000..3c0fe8447c12
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/MaxValueTest.java
@@ -0,0 +1,14 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class MaxValueTest {
+    @Test
+    public void maxTest() {
+        assertEquals(-1, MaxValue.max(-1, -3));
+        assertEquals(3, MaxValue.max(3, 2));
+        assertEquals(5, MaxValue.max(5, 5));
+    }
+}

From 152e29034d248226395ee659ce6deb2cbbc62805 Mon Sep 17 00:00:00 2001
From: Abhinav Pandey <abhinav.pandey.met22@itbhu.ac.in>
Date: Wed, 11 Oct 2023 17:29:55 +0530
Subject: [PATCH 0045/1338] Improved code readability and code quality (#4663)

* Fixed Small typos :-)

* Update BufferedReader.java

* Made the following changes :

* Improved readability of files and removed gramatical errors.

* Implemented data assigning instead of manually calling arr.ylength in several instances like FindMax, FindMaxRecursion etc.

* Removed unwanted params from several files

* Implemented Math methods in files math/FindMinRecursion.java and FindMaxRecursion.java

* Update src/main/java/com/thealgorithms/maths/FindMinRecursion.java

---------

Co-authored-by: Debasish Biswas <debasishbsws.dev@gmail.com>
---
 .../java/com/thealgorithms/maths/Average.java     |  2 +-
 .../thealgorithms/maths/DeterminantOfMatrix.java  |  2 +-
 .../java/com/thealgorithms/maths/DigitalRoot.java | 10 +++++-----
 .../com/thealgorithms/maths/DistanceFormula.java  |  4 ++--
 .../com/thealgorithms/maths/DudeneyNumber.java    | 10 +++++-----
 .../java/com/thealgorithms/maths/EulerMethod.java |  2 +-
 .../com/thealgorithms/maths/FindKthNumber.java    |  2 +-
 .../java/com/thealgorithms/maths/FindMax.java     |  7 ++++---
 .../com/thealgorithms/maths/FindMaxRecursion.java |  8 ++++----
 .../java/com/thealgorithms/maths/FindMin.java     |  2 +-
 .../com/thealgorithms/maths/FindMinRecursion.java | 15 ++++++++++++---
 src/main/java/com/thealgorithms/maths/GCD.java    |  6 +++---
 .../java/com/thealgorithms/maths/Gaussian.java    |  2 +-
 13 files changed, 41 insertions(+), 31 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Average.java b/src/main/java/com/thealgorithms/maths/Average.java
index ad37b78718c3..903afbafe35f 100644
--- a/src/main/java/com/thealgorithms/maths/Average.java
+++ b/src/main/java/com/thealgorithms/maths/Average.java
@@ -23,7 +23,7 @@ public static double average(double[] numbers) {
     }
 
     /**
-     * find average value of int array
+     * find average value of an int array
      *
      * @param numbers the array contains element and the sum does not excess long
      *                value limit
diff --git a/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java b/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
index 401bedbccdc0..79b0dafad8f4 100644
--- a/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
+++ b/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
@@ -4,7 +4,7 @@
 
 /*
  * @author Ojasva Jain
- * Determinant of Matrix Wikipedia link : https://en.wikipedia.org/wiki/Determinant
+ * Determinant of a Matrix Wikipedia link: https://en.wikipedia.org/wiki/Determinant
  */
 public class DeterminantOfMatrix {
 
diff --git a/src/main/java/com/thealgorithms/maths/DigitalRoot.java b/src/main/java/com/thealgorithms/maths/DigitalRoot.java
index 78066f404739..9eeb4a65f2ae 100644
--- a/src/main/java/com/thealgorithms/maths/DigitalRoot.java
+++ b/src/main/java/com/thealgorithms/maths/DigitalRoot.java
@@ -51,17 +51,17 @@ public static int digitalRoot(int n) {
         }
     }
 
-    // This function is used for finding the sum of digits of number
+    // This function is used for finding the sum of the digits of number
     public static int single(int n) {
         if (n <= 9) { // if n becomes less than 10 than return n
             return n;
         } else {
             return (n % 10) + single(n / 10); // n % 10 for extracting digits one by one
         }
-    } // n / 10 is the number obtainded after removing the digit one by one
-    // Sum of digits is stored in the Stack memory and then finally returned
+    } // n / 10 is the number obtained after removing the digit one by one
+    // The Sum of digits is stored in the Stack memory and then finally returned
 }
 /**
- * Time Complexity : O((Number of Digits)^2) Auxiliary Space Complexity :
- * O(Number of Digits) Constraints : 1 <= n <= 10^7
+ * Time Complexity: O((Number of Digits)^2) Auxiliary Space Complexity:
+ * O(Number of Digits) Constraints: 1 <= n <= 10^7
  */
diff --git a/src/main/java/com/thealgorithms/maths/DistanceFormula.java b/src/main/java/com/thealgorithms/maths/DistanceFormula.java
index 9a2654dbeedb..6efc2fbdff5d 100644
--- a/src/main/java/com/thealgorithms/maths/DistanceFormula.java
+++ b/src/main/java/com/thealgorithms/maths/DistanceFormula.java
@@ -16,7 +16,7 @@ public static int hammingDistance(int[] b1, int[] b2) {
         int d = 0;
 
         if (b1.length != b2.length) {
-            return -1; // error, both array must be have the same length
+            return -1; // error, both arrays must have the same length
         }
 
         for (int i = 0; i < b1.length; i++) {
@@ -31,7 +31,7 @@ public static double minkowskiDistance(double[] p1, double[] p2, int p) {
         double distance = 0.0;
 
         if (p1.length != p2.length) {
-            return -1; // error, both array must be have the same length
+            return -1; // error, both arrays must have the same length
         }
 
         for (int i = 0; i < p1.length; i++) {
diff --git a/src/main/java/com/thealgorithms/maths/DudeneyNumber.java b/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
index 69231af7bb85..3bb56c5ccdb7 100644
--- a/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
@@ -16,21 +16,21 @@ public static boolean isDudeney(int n) {
         if (cube_root * cube_root * cube_root != n) {
             return false;
         }
-        int sum_of_digits = 0; // Stores the sums of the digit of the entered number
+        int sum_of_digits = 0; // Stores the sums of the digits of the entered number
         int temp = n; // A temporary variable to store the entered number
-        // Loop to calculate sum of the digits.
+        // Loop to calculate the sum of the digits.
         while (temp > 0) {
-            // Extracting Last digit of the number
+            // Extracting the Last digit of the number
             int rem = temp % 10;
 
-            // Calculating sum of digits.
+            // Calculating the sum of digits.
             sum_of_digits += rem;
 
             // Removing the last digit
             temp /= 10;
         }
 
-        // If the cube root of the number is not equal to the sum of its digits we return false.
+        // If the cube root of the number is not equal to the sum of its digits, we return false.
         return cube_root == sum_of_digits;
     }
 }
diff --git a/src/main/java/com/thealgorithms/maths/EulerMethod.java b/src/main/java/com/thealgorithms/maths/EulerMethod.java
index 336e23dd489c..40e654626a23 100644
--- a/src/main/java/com/thealgorithms/maths/EulerMethod.java
+++ b/src/main/java/com/thealgorithms/maths/EulerMethod.java
@@ -87,7 +87,7 @@ public static ArrayList<double[]> eulerFull(double xStart, double xEnd, double s
         double xCurrent = xStart;
 
         while (xCurrent < xEnd) {
-            // Euler method for next step
+            // Euler's method for next step
             yCurrent = eulerStep(xCurrent, stepSize, yCurrent, differentialEquation);
             xCurrent += stepSize;
             double[] point = {xCurrent, yCurrent};
diff --git a/src/main/java/com/thealgorithms/maths/FindKthNumber.java b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
index d869ca47c759..bcb83b5ee2fc 100644
--- a/src/main/java/com/thealgorithms/maths/FindKthNumber.java
+++ b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
@@ -11,7 +11,7 @@ public class FindKthNumber {
     private static final Random random = new Random();
 
     public static void main(String[] args) {
-        /* generate array with random size and random elements */
+        /* generate an array with random size and random elements */
         int[] nums = generateArray(100);
 
         /* get 3th largest element */
diff --git a/src/main/java/com/thealgorithms/maths/FindMax.java b/src/main/java/com/thealgorithms/maths/FindMax.java
index 76bde5ff600f..0ff2bdd191ac 100644
--- a/src/main/java/com/thealgorithms/maths/FindMax.java
+++ b/src/main/java/com/thealgorithms/maths/FindMax.java
@@ -12,11 +12,12 @@ private FindMax() {
      * @return the maximum value stored in the input array
      */
     public static int findMax(final int[] array) {
-        if (array.length == 0) {
-            throw new IllegalArgumentException("array must be non-empty.");
+        int n = array.length;
+        if (n == 0) {
+            throw new IllegalArgumentException("Array must be non-empty.");
         }
         int max = array[0];
-        for (int i = 1; i < array.length; i++) {
+        for (int i = 1; i < n; i++) {
             if (array[i] > max) {
                 max = array[i];
             }
diff --git a/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java b/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java
index 574fe5f2b1b8..950a0ebe0085 100644
--- a/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java
+++ b/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java
@@ -5,7 +5,7 @@ public final class FindMaxRecursion {
     private FindMaxRecursion() {
     }
     /**
-     * Get max of array using divide and conquer algorithm
+     * Get max of an array using divide and conquer algorithm
      *
      * @param array contains elements
      * @param low the index of the first element
@@ -14,7 +14,7 @@ private FindMaxRecursion() {
      */
     public static int max(final int[] array, final int low, final int high) {
         if (array.length == 0) {
-            throw new IllegalArgumentException("array must be non-empty.");
+            throw new IllegalArgumentException("Array must be non-empty.");
         }
         if (low == high) {
             return array[low]; // or array[high]
@@ -25,11 +25,11 @@ public static int max(final int[] array, final int low, final int high) {
         int leftMax = max(array, low, mid); // get max in [low, mid]
         int rightMax = max(array, mid + 1, high); // get max in [mid+1, high]
 
-        return leftMax < rightMax ? rightMax : leftMax;
+        return Math.max(leftMax, rightMax);
     }
 
     /**
-     * Get max of array using recursion algorithm
+     * Get max of an array using recursion algorithm
      *
      * @param array contains elements
      * @return max value of {@code array}
diff --git a/src/main/java/com/thealgorithms/maths/FindMin.java b/src/main/java/com/thealgorithms/maths/FindMin.java
index 10a03c801098..76fa2e815ee0 100644
--- a/src/main/java/com/thealgorithms/maths/FindMin.java
+++ b/src/main/java/com/thealgorithms/maths/FindMin.java
@@ -13,7 +13,7 @@ private FindMin() {
      */
     public static int findMin(final int[] array) {
         if (array.length == 0) {
-            throw new IllegalArgumentException("array must be non-empty.");
+            throw new IllegalArgumentException("Array must be non-empty.");
         }
         int min = array[0];
         for (int i = 1; i < array.length; i++) {
diff --git a/src/main/java/com/thealgorithms/maths/FindMinRecursion.java b/src/main/java/com/thealgorithms/maths/FindMinRecursion.java
index 6ffe034ee40f..a2cf1b36d6cb 100644
--- a/src/main/java/com/thealgorithms/maths/FindMinRecursion.java
+++ b/src/main/java/com/thealgorithms/maths/FindMinRecursion.java
@@ -4,6 +4,16 @@ public final class FindMinRecursion {
 
     private FindMinRecursion() {
     }
+
+    /**
+     * Get min of an array using divide and conquer algorithm
+     *
+     * @param array contains elements
+     * @param low the index of the first element
+     * @param high the index of the last element
+     * @return min of {@code array}
+     */
+
     public static int min(final int[] array, final int low, final int high) {
         if (array.length == 0) {
             throw new IllegalArgumentException("array must be non-empty.");
@@ -17,14 +27,13 @@ public static int min(final int[] array, final int low, final int high) {
         int leftMin = min(array, low, mid); // get min in [low, mid]
         int rightMin = min(array, mid + 1, high); // get min in [mid+1, high]
 
-        return leftMin > rightMin ? rightMin : leftMin;
+        return Math.min(leftMin, rightMin);
     }
 
     /**
-     * Get min of array using recursion algorithm
+     * Get min of an array using recursion algorithm
      *
      * @param array contains elements
-     * @param len length of given array
      * @return min value of {@code array}
      */
     public static int min(final int[] array) {
diff --git a/src/main/java/com/thealgorithms/maths/GCD.java b/src/main/java/com/thealgorithms/maths/GCD.java
index 3a69fcab413f..0f3125bde209 100644
--- a/src/main/java/com/thealgorithms/maths/GCD.java
+++ b/src/main/java/com/thealgorithms/maths/GCD.java
@@ -1,15 +1,15 @@
 package com.thealgorithms.maths;
 
 /**
- * This is Euclid's algorithm which is used to find the greatest common
- * denominator Overide function name gcd
+ * This is Euclid's algorithm, used to find the greatest common
+ * denominator Override function name gcd
  *
  * @author Oskar Enmalm 3/10/17
  */
 public class GCD {
 
     /**
-     * get greatest common divisor
+     * get the greatest common divisor
      *
      * @param num1 the first number
      * @param num2 the second number
diff --git a/src/main/java/com/thealgorithms/maths/Gaussian.java b/src/main/java/com/thealgorithms/maths/Gaussian.java
index fd0f86d89f89..442c51e9d32d 100644
--- a/src/main/java/com/thealgorithms/maths/Gaussian.java
+++ b/src/main/java/com/thealgorithms/maths/Gaussian.java
@@ -38,7 +38,7 @@ public static double[][] gaussianElimination(int mat_size, int i, double[][] mat
         return mat;
     }
 
-    // calculate the x_1, x_2,... values of the gaussian and save it in an arraylist.
+    // calculate the x_1, x_2, ... values of the gaussian and save it in an arraylist.
     public static ArrayList<Double> valueOfGaussian(int mat_size, double[][] x, double[][] mat) {
         ArrayList<Double> answerArray = new ArrayList<Double>();
         int i, j;

From e9bbf35ff9ab85dd968fcec14f0a4b057ecccb8b Mon Sep 17 00:00:00 2001
From: Ricardo Ramos <36955909+ricardo-ramos-moura@users.noreply.github.com>
Date: Wed, 11 Oct 2023 18:21:53 -0300
Subject: [PATCH 0046/1338] Add `FloorTest` and clean-up `Floor` (#4769)

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Ricardo Ramos <0102016812@grupotel.corp>
---
 DIRECTORY.md                                  | 103 ++++++++++++++----
 .../java/com/thealgorithms/maths/Floor.java   |  11 +-
 .../com/thealgorithms/maths/FloorTest.java    |  28 +++++
 3 files changed, 114 insertions(+), 28 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/FloorTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 3aa2bde37be0..6de516618484 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -19,10 +19,14 @@
             * [PowerSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/PowerSum.java)
             * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
           * bitmanipulation
+            * [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
+            * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
             * [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
             * [IsPowerTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java)
+            * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
             * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
+            * [SingleBitOperations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java)
           * ciphers
             * a5
               * [A5Cipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/A5Cipher.java)
@@ -77,9 +81,9 @@
               * [LFUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java)
               * [LRUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java)
               * [MRUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java)
-            * disjointsets
-              * [DisjointSets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsets/DisjointSets.java)
-              * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsets/Node.java)
+            * disjointsetunion
+              * [DisjointSetUnion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java)
+              * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/Node.java)
             * dynamicarray
               * [DynamicArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java)
             * graphs
@@ -129,7 +133,10 @@
               * [Merge K SortedLinkedlist](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java)
               * [MergeSortedArrayList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java)
               * [MergeSortedSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java)
+              * [QuickSortLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java)
               * [RandomNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/RandomNode.java)
+              * [ReverseKGroup](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java)
+              * [RotateSinglyLinkedLists](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java)
               * [SearchSinglyLinkedListRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java)
               * [SinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java)
               * [SkipList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java)
@@ -142,17 +149,7 @@
               * [PriorityQueues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java)
               * [Queues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/Queues.java)
             * stacks
-              * [BalancedBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/BalancedBrackets.java)
-              * [CalculateMaxOfMin](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/CalculateMaxOfMin.java)
-              * [DecimalToAnyUsingStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/DecimalToAnyUsingStack.java)
-              * [DuplicateBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/DuplicateBrackets.java)
-              * [InfixToPostfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/InfixToPostfix.java)
-              * [LargestRectangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/LargestRectangle.java)
-              * [MaximumMinimumWindow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/MaximumMinimumWindow.java)
-              * [NextGraterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/NextGraterElement.java)
-              * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/NextSmallerElement.java)
               * [NodeStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java)
-              * [PostfixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/PostfixToInfix.java)
               * [ReverseStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java)
               * [StackArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java)
               * [StackArrayList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java)
@@ -214,7 +211,6 @@
             * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java)
             * [CountFriendsPairing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java)
             * [DiceThrow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java)
-            * [DyanamicProgrammingKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/DyanamicProgrammingKnapsack.java)
             * [EditDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java)
             * [EggDropping](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java)
             * [Fibonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java)
@@ -244,9 +240,15 @@
             * [SubsetSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java)
             * [Sum Of Subset](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Sum_Of_Subset.java)
             * [UniquePaths](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java)
+            * [WildcardMatching](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java)
             * [WineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java)
           * geometry
             * [GrahamScan](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/GrahamScan.java)
+          * greedyalgorithms
+            * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
+            * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java)
+            * [FractionalKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
+            * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
           * io
             * [BufferedReader](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/io/BufferedReader.java)
           * maths
@@ -307,7 +309,9 @@
             * [MagicSquare](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MagicSquare.java)
             * [MatrixUtil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MatrixUtil.java)
             * [MaxValue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MaxValue.java)
+            * [Means](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Means.java)
             * [Median](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Median.java)
+            * [MillerRabinPrimalityCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java)
             * [MinValue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MinValue.java)
             * [MobiusFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MobiusFunction.java)
             * [Mode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Mode.java)
@@ -325,13 +329,14 @@
             * [PollardRho](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PollardRho.java)
             * [Pow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Pow.java)
             * [PowerOfTwoOrNot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PowerOfTwoOrNot.java)
-            * [PowRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PowRecursion.java)
+            * [PowerUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PowerUsingRecursion.java)
             * [PrimeCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PrimeCheck.java)
             * [PrimeFactorization](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PrimeFactorization.java)
             * [PronicNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PronicNumber.java)
             * [PythagoreanTriple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java)
             * [ReverseNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ReverseNumber.java)
             * [RomanNumeralUtil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/RomanNumeralUtil.java)
+            * [SecondMinMax](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SecondMinMax.java)
             * [SimpsonIntegration](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java)
             * [SquareFreeInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareFreeInteger.java)
             * [SquareRootWithBabylonianMethod](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java)
@@ -355,13 +360,21 @@
             * [ColorContrastRatio](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java)
             * [InverseOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java)
             * [matrixTranspose](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/matrixTranspose.java)
+            * [MedianOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java)
             * [MedianOfRunningArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java)
+            * [MedianOfRunningArrayByte](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayByte.java)
+            * [MedianOfRunningArrayDouble](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayDouble.java)
+            * [MedianOfRunningArrayFloat](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayFloat.java)
+            * [MedianOfRunningArrayInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayInteger.java)
+            * [MedianOfRunningArrayLong](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayLong.java)
+            * [MirrorOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java)
             * [PalindromePrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromePrime.java)
             * [PalindromeSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java)
             * [RangeInSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java)
             * [Sort012D](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sort012D.java)
             * [Sparcity](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sparcity.java)
             * [ThreeSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java)
+            * [TwoSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/TwoSumProblem.java)
             * [WordBoggle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/WordBoggle.java)
           * others
             * [ArrayLeftRotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java)
@@ -412,7 +425,6 @@
             * [RotateMatriceBy90Degree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RotateMatriceBy90Degree.java)
             * [SieveOfEratosthenes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java)
             * [SkylineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SkylineProblem.java)
-            * [StackPostfixNotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/StackPostfixNotation.java)
             * [StringMatchFiniteAutomata](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java)
             * [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Sudoku.java)
             * [TopKWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TopKWords.java)
@@ -421,6 +433,7 @@
             * [Verhoeff](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Verhoeff.java)
           * scheduling
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
+            * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
             * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
           * searches
@@ -444,6 +457,7 @@
             * [PerfectBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java)
             * [QuickSelect](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/QuickSelect.java)
             * [RabinKarpAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java)
+            * [RecursiveBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java)
             * [RowColumnWiseSorted2dArrayBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java)
             * [SaddlebackSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java)
             * [SearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java)
@@ -495,7 +509,20 @@
             * [TopologicalSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/TopologicalSort.java)
             * [TreeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/TreeSort.java)
             * [WiggleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/WiggleSort.java)
+          * stacks
+            * [BalancedBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java)
+            * [CalculateMaxOfMin](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/CalculateMaxOfMin.java)
+            * [DecimalToAnyUsingStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java)
+            * [DuplicateBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java)
+            * [InfixToPostfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java)
+            * [LargestRectangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/LargestRectangle.java)
+            * [MaximumMinimumWindow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java)
+            * [NextGraterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextGraterElement.java)
+            * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
+            * [PostfixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java)
+            * [StackPostfixNotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
           * strings
+            * [AhoCorasick](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/AhoCorasick.java)
             * [Alphabetical](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Alphabetical.java)
             * [Anagrams](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Anagrams.java)
             * [CharactersSame](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CharactersSame.java)
@@ -514,6 +541,7 @@
             * [PermuteString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/PermuteString.java)
             * [ReverseString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseString.java)
             * [ReverseStringRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java)
+            * [ReverseWordsInString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java)
             * [Rotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Rotation.java)
             * [StringCompression](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/StringCompression.java)
             * [Upper](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Upper.java)
@@ -536,10 +564,14 @@
             * [PowerSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PowerSumTest.java)
             * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
           * bitmanipulation
+            * [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
+            * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
             * [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
             * [IsPowerTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java)
+            * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
             * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
+            * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
           * ciphers
             * a5
               * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
@@ -573,6 +605,8 @@
               * [LFUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java)
               * [LRUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java)
               * [MRUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java)
+            * disjointsetunion
+              * [DisjointSetUnionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java)
             * graphs
               * [HamiltonianCycleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java)
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
@@ -589,6 +623,9 @@
               * [FibonacciHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
             * lists
+              * [QuickSortLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java)
+              * [ReverseKGroupTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java)
+              * [RotateSinglyLinkedListsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java)
               * [SinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java)
               * [SkipListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java)
             * queues
@@ -622,13 +659,22 @@
             * [climbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/climbStairsTest.java)
             * [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
             * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
+            * [KnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
             * [LevenshteinDistanceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
             * [MinimumPathSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java)
+            * [MinimumSumPartitionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java)
             * [OptimalJobSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
             * [PartitionProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java)
             * [SubsetCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java)
+            * [UniquePathsTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java)
+            * [WildcardMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java)
           * geometry
             * [GrahamScanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
+          * greedyalgorithms
+            * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
+            * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java)
+            * [FractionalKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
+            * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
           * io
             * [BufferedReaderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/io/BufferedReaderTest.java)
           * maths
@@ -655,8 +701,11 @@
             * [FFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FFTTest.java)
             * [FibonacciJavaStreamsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciJavaStreamsTest.java)
             * [FibonacciNumberCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciNumberCheckTest.java)
+            * [FindMaxRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java)
             * [FindMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMaxTest.java)
+            * [FindMinRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMinRecursionTest.java)
             * [FindMinTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMinTest.java)
+            * [FloorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FloorTest.java)
             * [FrizzyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FrizzyNumberTest.java)
             * [GaussianTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GaussianTest.java)
             * [GCDTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GCDTest.java)
@@ -670,7 +719,11 @@
             * [LiouvilleLambdaFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java)
             * [LongDivisionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LongDivisionTest.java)
             * [LucasSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LucasSeriesTest.java)
+            * [MaxValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MaxValueTest.java)
+            * [MeansTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MeansTest.java)
             * [MedianTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MedianTest.java)
+            * [MillerRabinPrimalityCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java)
+            * [MinValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MinValueTest.java)
             * [MobiusFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java)
             * [NthUglyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java)
             * [PalindromeNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java)
@@ -682,11 +735,13 @@
             * [PerimeterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PerimeterTest.java)
             * [PollardRhoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PollardRhoTest.java)
             * [PowerOfTwoOrNotTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java)
+            * [PowerUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java)
             * [PrimeCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PrimeCheckTest.java)
             * [PrimeFactorizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java)
             * [PronicNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PronicNumberTest.java)
             * [PythagoreanTripleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java)
             * [ReverseNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ReverseNumberTest.java)
+            * [SecondMinMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java)
             * [SquareFreeIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java)
             * [SquareRootwithBabylonianMethodTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareRootwithBabylonianMethodTest.java)
             * [SquareRootWithNewtonRaphsonTestMethod](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonTestMethod.java)
@@ -699,10 +754,15 @@
             * [TestArmstrong](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TestArmstrong.java)
             * [TwinPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TwinPrimeTest.java)
             * [VolumeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/VolumeTest.java)
+          * misc
+            * [MedianOfMatrixtest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java)
+            * [MedianOfRunningArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java)
+            * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java)
+            * [PalindromeSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java)
+            * [TwoSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
           * others
             * [ArrayLeftRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java)
             * [BestFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BestFitCPUTest.java)
-            * [CalculateMaxOfMinTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CalculateMaxOfMinTest.java)
             * cn
               * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java)
             * [ConwayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ConwayTest.java)
@@ -723,13 +783,12 @@
             * [NextFitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/NextFitTest.java)
             * [PasswordGenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/PasswordGenTest.java)
             * [SieveOfEratosthenesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SieveOfEratosthenesTest.java)
-            * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/StackPostfixNotationTest.java)
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
-            * [UniquePathsTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/UniquePathsTests.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
           * scheduling
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
+            * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
             * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)
           * searches
@@ -741,6 +800,7 @@
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
             * [QuickSelectTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/QuickSelectTest.java)
             * [RabinKarpAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java)
+            * [RecursiveBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java)
             * [RowColumnWiseSorted2dArrayBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java)
             * [sortOrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearchTest.java)
             * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
@@ -775,7 +835,11 @@
             * [TopologicalSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java)
             * [TreeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TreeSortTest.java)
             * [WiggleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java)
+          * stacks
+            * [CalculateMaxOfMinTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/CalculateMaxOfMinTest.java)
+            * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
           * strings
+            * [AhoCorasickTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
             * [AlphabeticalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java)
             * [AnagramsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AnagramsTest.java)
             * [CharacterSameTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CharacterSameTest.java)
@@ -792,6 +856,7 @@
             * [PangramTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PangramTest.java)
             * [ReverseStringRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java)
             * [ReverseStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseStringTest.java)
+            * [ReverseWordsInStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java)
             * [RotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/RotationTest.java)
             * [StringCompressionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/StringCompressionTest.java)
             * [UpperTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/UpperTest.java)
diff --git a/src/main/java/com/thealgorithms/maths/Floor.java b/src/main/java/com/thealgorithms/maths/Floor.java
index bd4df6fcb852..271fc42d0d17 100644
--- a/src/main/java/com/thealgorithms/maths/Floor.java
+++ b/src/main/java/com/thealgorithms/maths/Floor.java
@@ -1,15 +1,8 @@
 package com.thealgorithms.maths;
 
-import java.util.Random;
+public final class Floor {
 
-public class Floor {
-
-    public static void main(String[] args) {
-        Random random = new Random();
-        for (int i = 1; i <= 1000; ++i) {
-            double randomNumber = random.nextDouble();
-            assert floor(randomNumber) == Math.floor(randomNumber);
-        }
+    private Floor() {
     }
 
     /**
diff --git a/src/test/java/com/thealgorithms/maths/FloorTest.java b/src/test/java/com/thealgorithms/maths/FloorTest.java
new file mode 100644
index 000000000000..19aed70ccb71
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/FloorTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+public class FloorTest {
+    @Test
+    public void testFloorWholeNumber() {
+        assertEquals(0, Floor.floor(0));
+        assertEquals(1, Floor.floor(1));
+        assertEquals(-1, Floor.floor(-1));
+        assertEquals(42, Floor.floor(42));
+        assertEquals(-42, Floor.floor(-42));
+    }
+
+    @Test
+    public void testFloorDoubleNumber() {
+        assertEquals(0, Floor.floor(0.1));
+        assertEquals(1, Floor.floor(1.9));
+        assertEquals(-2, Floor.floor(-1.1));
+        assertEquals(-43, Floor.floor(-42.7));
+    }
+
+    @Test
+    public void testFloorNegativeZero() {
+        assertEquals(-0.0, Floor.floor(-0.0));
+    }
+}

From 1dc64b16859d95446a8bfe1c50692ce57316bc42 Mon Sep 17 00:00:00 2001
From: "D.Sunil" <sunilnitdgp5@gmail.com>
Date: Fri, 13 Oct 2023 01:43:32 +0530
Subject: [PATCH 0047/1338] Update BinarySearch (#4747)

---
 .../searches/PerfectBinarySearch.java         | 62 +++++++++++++------
 .../searches/PerfectBinarySearchTest.java     | 43 +++++++++++++
 2 files changed, 87 insertions(+), 18 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java

diff --git a/src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java b/src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java
index bfeb5efc3a62..495e2e41bc5b 100644
--- a/src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java
@@ -1,28 +1,54 @@
 package com.thealgorithms.searches;
 
-class PerfectBinarySearch {
+import com.thealgorithms.devutils.searches.SearchAlgorithm;
 
-    static int binarySearch(int[] arr, int target) {
-        int low = 0;
-        int high = arr.length - 1;
+/**
+ * Binary search is one of the most popular algorithms The algorithm finds the
+ * position of a target value within a sorted array
+ *
+ * <p>
+ * Worst-case performance O(log n) Best-case performance O(1) Average
+ * performance O(log n) Worst-case space complexity O(1)
+ *
+ * @author D Sunil (https://github.com/sunilnitdgp)
+ * @see SearchAlgorithm
+ */
 
-        while (low <= high) {
-            int mid = (low + high) / 2;
+public class PerfectBinarySearch<T> implements SearchAlgorithm {
 
-            if (arr[mid] == target) {
-                return mid;
-            } else if (arr[mid] > target) {
-                high = mid - 1;
+    /**
+     * @param array is an array where the element should be found
+     * @param key is an element which should be found
+     * @param <T> is any comparable type
+     * @return index of the element
+     */
+    @Override
+    public <T extends Comparable<T>> int find(T[] array, T key) {
+        return search(array, key, 0, array.length - 1);
+    }
+
+    /**
+     * This method implements the Generic Binary Search iteratively.
+     *
+     * @param array The array to make the binary search
+     * @param key   The number you are looking for
+     * @return the location of the key, or -1 if not found
+     */
+    private static <T extends Comparable<T>> int search(T[] array, T key, int left, int right) {
+        while (left <= right) {
+            int median = (left + right) >>> 1;
+            int comp = key.compareTo(array[median]);
+
+            if (comp == 0) {
+                return median; // Key found
+            }
+
+            if (comp < 0) {
+                right = median - 1; // Adjust the right bound
             } else {
-                low = mid + 1;
+                left = median + 1; // Adjust the left bound
             }
         }
-        return -1;
-    }
-
-    public static void main(String[] args) {
-        int[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
-        assert PerfectBinarySearch.binarySearch(array, -1) == -1;
-        assert PerfectBinarySearch.binarySearch(array, 11) == -1;
+        return -1; // Key not found
     }
 }
diff --git a/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
new file mode 100644
index 000000000000..0ba0b03b33b4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
@@ -0,0 +1,43 @@
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.thealgorithms.searches.PerfectBinarySearch;
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author D Sunil (https://github.com/sunilnitdgp)
+ * @see PerfectBinarySearch
+ */
+public class PerfectBinarySearchTest {
+
+    @Test
+    public void testIntegerBinarySearch() {
+        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        PerfectBinarySearch<Integer> binarySearch = new PerfectBinarySearch<>();
+
+        // Test cases for elements present in the array
+        assertEquals(0, binarySearch.find(array, 1)); // First element
+        assertEquals(4, binarySearch.find(array, 5)); // Middle element
+        assertEquals(9, binarySearch.find(array, 10)); // Last element
+        assertEquals(6, binarySearch.find(array, 7)); // Element in the middle
+
+        // Test cases for elements not in the array
+        assertEquals(-1, binarySearch.find(array, 0)); // Element before the array
+        assertEquals(-1, binarySearch.find(array, 11)); // Element after the array
+        assertEquals(-1, binarySearch.find(array, 100)); // Element not in the array
+    }
+
+    @Test
+    public void testStringBinarySearch() {
+        String[] array = {"apple", "banana", "cherry", "date", "fig"};
+        PerfectBinarySearch<String> binarySearch = new PerfectBinarySearch<>();
+
+        // Test cases for elements not in the array
+        assertEquals(-1, binarySearch.find(array, "apricot")); // Element not in the array
+        assertEquals(-1, binarySearch.find(array, "bananaa")); // Element not in the array
+
+        // Test cases for elements present in the array
+        assertEquals(0, binarySearch.find(array, "apple")); // First element
+        assertEquals(2, binarySearch.find(array, "cherry")); // Middle element
+        assertEquals(4, binarySearch.find(array, "fig")); // Last element
+    }
+}

From 24a82230626e986392bcba7dc86b80118aefcdc3 Mon Sep 17 00:00:00 2001
From: Pronay Debnath <pronayd4455@gmail.com>
Date: Sat, 14 Oct 2023 00:53:30 +0530
Subject: [PATCH 0048/1338] Added [FEATURE REQUEST] Golden Ration formula to
 find Nth Fibonacci number #4505 (#4513)

* Create FibonacciNumber.java

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Create FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumber.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update FibonacciNumber.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumber.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Delete src/main/java/com/thealgorithms/maths/FibonacciNumberTest.java

* Create FibonacciNumberTest.java

* Update FibonacciNumber.java

* Update FibonacciNumberTest.java

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Update FibonacciNumberTest.java

* Update src/test/java/com/thealgorithms/maths/FibonacciNumberTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Create FibonacciCalculator.java

* Update FibonacciNumberTest.java

* Update and rename FibonacciCalculator.java to FibCalc.java

* Update FibonacciNumberTest.java

* Update FibCalc.java

* Update FibonacciNumber.java

* Delete src/test/java/com/thealgorithms/maths/FibCalc.java

* Create FibCalc.java

* Update FibonacciNumberTest.java

* Update FibCalc.java

* Update FibonacciNumberTest.java

* Update FibonacciNumber.java

* Update FibonacciNumberTest.java

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Update FibonacciNumberTest.java

* Update FibonacciNumber.java

* fix: use proper name

* fix: use proper class name

* tests: add `returnsCorrectValues`

* Update and rename FibCalc.java to Fibonacci.java

* Update Fibonacci.java

* Update FibonacciNumber.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update Fibonacci.java

* Update FibonacciNumber.java

* Update and rename FibCalcTest.java to FibonacciTest.java

* Update FibonacciNumber.java

* Update Fibonacci.java

* Update Fibonacci.java

* Update Fibonacci.java

* Update FibonacciTest.java

* Update Fibonacci.java

* Update src/main/java/com/thealgorithms/maths/Fibonacci.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/maths/FibonacciNumberTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/maths/FibonacciNumberTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update FibonacciTest.java

* Update FibonacciNumberTest.java

* Update FibonacciNumberTest.java

* Update FibonacciTest.java

* Update src/main/java/com/thealgorithms/maths/Fibonacci.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/maths/FibonacciNumberTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/maths/FibonacciTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/Fibonacci.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/FibonacciNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/maths/FibonacciNumberTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/maths/FibonacciNumberTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/maths/FibonacciNumberTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update FibonacciNumber.java

* Update FibonacciNumber.java

* Update Fibonacci.java

* Update FibonacciNumber.java

* Update and rename FibonacciNumber.java to FibonacciNumberGoldenRation.java

* Update and rename FibonacciNumberTest.java to FibonacciNumberGoldenRationTest.java

* Update Fibonacci.java

* Update FibonacciNumberGoldenRation.java

* Update FibonacciNumberGoldenRationTest.java

* Update FibonacciTest.java

* Update Fibonacci.java

* Update FibonacciNumberGoldenRationTest.java

* Update FibonacciNumberGoldenRationTest.java

* Update FibonacciNumberGoldenRation.java

* Update FibonacciNumberGoldenRation.java

* Update FibonacciNumberGoldenRationTest.java

* Update FibonacciNumberGoldenRationTest.java

* Update src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update and rename Fibonacci.java to FibonacciLoop.java

* Update FibonacciNumberGoldenRation.java

* Update FibonacciNumberGoldenRationTest.java

* Update and rename FibonacciTest.java to FibonacciLoopTest.java

* Update FibonacciLoop.java

* Update FibonacciLoop.java

* Update FibonacciNumberGoldenRation.java

* docs: add missing dot

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Co-authored-by: vil02 <vil02@o2.pl>
---
 .../thealgorithms/maths/FibonacciLoop.java    | 41 +++++++++++++++
 .../maths/FibonacciNumberGoldenRation.java    | 50 +++++++++++++++++++
 .../maths/FibonacciLoopTest.java              | 36 +++++++++++++
 .../FibonacciNumberGoldenRationTest.java      | 29 +++++++++++
 4 files changed, 156 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/FibonacciLoop.java
 create mode 100644 src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java
 create mode 100644 src/test/java/com/thealgorithms/maths/FibonacciLoopTest.java
 create mode 100644 src/test/java/com/thealgorithms/maths/FibonacciNumberGoldenRationTest.java

diff --git a/src/main/java/com/thealgorithms/maths/FibonacciLoop.java b/src/main/java/com/thealgorithms/maths/FibonacciLoop.java
new file mode 100644
index 000000000000..de23a4305c3f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/FibonacciLoop.java
@@ -0,0 +1,41 @@
+package com.thealgorithms.maths;
+
+import java.math.BigInteger;
+
+/**
+ * This class provides methods for calculating Fibonacci numbers using BigInteger for large values of 'n'.
+ */
+public final class FibonacciLoop {
+
+    private FibonacciLoop() {
+        // Private constructor to prevent instantiation of this utility class.
+    }
+
+    /**
+     * Calculates the nth Fibonacci number.
+     *
+     * @param n The index of the Fibonacci number to calculate.
+     * @return The nth Fibonacci number as a BigInteger.
+     * @throws IllegalArgumentException if the input 'n' is a negative integer.
+     */
+    public static BigInteger compute(final int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input 'n' must be a non-negative integer.");
+        }
+
+        if (n <= 1) {
+            return BigInteger.valueOf(n);
+        }
+
+        BigInteger prev = BigInteger.ZERO;
+        BigInteger current = BigInteger.ONE;
+
+        for (int i = 2; i <= n; i++) {
+            BigInteger next = prev.add(current);
+            prev = current;
+            current = next;
+        }
+
+        return current;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java b/src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java
new file mode 100644
index 000000000000..4df37a40f541
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java
@@ -0,0 +1,50 @@
+package com.thealgorithms.maths;
+
+/**
+ * This class provides methods for calculating Fibonacci numbers using Binet's formula.
+ * Binet's formula is based on the golden ratio and allows computing Fibonacci numbers efficiently.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Fibonacci_sequence#Binet's_formula">Binet's formula on Wikipedia</a>
+ */
+public final class FibonacciNumberGoldenRation {
+    private FibonacciNumberGoldenRation() {
+        // Private constructor to prevent instantiation of this utility class.
+    }
+
+    /**
+     * Compute the limit for 'n' that fits in a long data type.
+     * Reducing the limit to 70 due to potential floating-point arithmetic errors
+     * that may result in incorrect results for larger inputs.
+     */
+    public static final int MAX_ARG = 70;
+
+    /**
+     * Calculates the nth Fibonacci number using Binet's formula.
+     *
+     * @param n The index of the Fibonacci number to calculate.
+     * @return The nth Fibonacci number as a long.
+     * @throws IllegalArgumentException if the input 'n' is negative or exceeds the range of a long data type.
+     */
+    public static long compute(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input 'n' must be a non-negative integer.");
+        }
+
+        if (n > MAX_ARG) {
+            throw new IllegalArgumentException("Input 'n' is too big to give accurate result.");
+        }
+
+        if (n <= 1) {
+            return n;
+        }
+
+        // Calculate the nth Fibonacci number using the golden ratio formula
+        final double sqrt5 = Math.sqrt(5);
+        final double phi = (1 + sqrt5) / 2;
+        final double psi = (1 - sqrt5) / 2;
+        final double result = (Math.pow(phi, n) - Math.pow(psi, n)) / sqrt5;
+
+        // Round to the nearest integer and return as a long
+        return Math.round(result);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/FibonacciLoopTest.java b/src/test/java/com/thealgorithms/maths/FibonacciLoopTest.java
new file mode 100644
index 000000000000..93aec39765d4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/FibonacciLoopTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.math.BigInteger;
+import org.junit.jupiter.api.Test;
+
+public class FibonacciLoopTest {
+    @Test
+    public void checkValueAtZero() {
+        assertEquals(BigInteger.ZERO, FibonacciLoop.compute(0));
+    }
+
+    @Test
+    public void checkValueAtOne() {
+        assertEquals(BigInteger.ONE, FibonacciLoop.compute(1));
+    }
+
+    @Test
+    public void checkValueAtTwo() {
+        assertEquals(BigInteger.ONE, FibonacciLoop.compute(2));
+    }
+
+    @Test
+    public void checkRecurrenceRelation() {
+        for (int i = 0; i < 100; ++i) {
+            assertEquals(FibonacciLoop.compute(i + 2), FibonacciLoop.compute(i + 1).add(FibonacciLoop.compute(i)));
+        }
+    }
+
+    @Test
+    public void checkNegativeInput() {
+        assertThrows(IllegalArgumentException.class, () -> { FibonacciLoop.compute(-1); });
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/FibonacciNumberGoldenRationTest.java b/src/test/java/com/thealgorithms/maths/FibonacciNumberGoldenRationTest.java
new file mode 100644
index 000000000000..e3f7bf3e0fed
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/FibonacciNumberGoldenRationTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.math.BigInteger;
+import org.junit.jupiter.api.Test;
+
+public class FibonacciNumberGoldenRationTest {
+
+    @Test
+    public void returnsCorrectValues() {
+        for (int n = 0; n <= FibonacciNumberGoldenRation.MAX_ARG; ++n) {
+            final var actual = FibonacciNumberGoldenRation.compute(n);
+            final var expected = FibonacciLoop.compute(n);
+            assertEquals(expected, BigInteger.valueOf(actual));
+        }
+    }
+
+    @Test
+    public void throwsIllegalArgumentExceptionForNegativeInput() {
+        assertThrows(IllegalArgumentException.class, () -> { FibonacciNumberGoldenRation.compute(-1); });
+    }
+
+    @Test
+    public void throwsIllegalArgumentExceptionForLargeInput() {
+        assertThrows(IllegalArgumentException.class, () -> { FibonacciNumberGoldenRation.compute(FibonacciNumberGoldenRation.MAX_ARG + 1); });
+    }
+}

From 48ae88f09d595bf6bdd3440b003e08419c885126 Mon Sep 17 00:00:00 2001
From: Lukas <142339568+lukasb1b@users.noreply.github.com>
Date: Sun, 15 Oct 2023 09:03:25 +0200
Subject: [PATCH 0049/1338] Bit swap (#4770)

* Create BitSwap.java

* Create BitSwapTest.java

* Update BitSwap.java

* Update BitSwap.java

* Update BitSwapTest.java

* Update BitSwap.java

* Update BitSwap.java

* Update BitSwapTest.java

* Update BitSwapTest.java

* Update src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update BitSwap.java

* Update BitSwap.java

* Update BitSwap.java

* Update src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* style: remove redundant blank line

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../thealgorithms/bitmanipulation/BitSwap.java    | 15 +++++++++++++++
 .../bitmanipulation/BitSwapTest.java              | 13 +++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java b/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java
new file mode 100644
index 000000000000..40b3097b1276
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java
@@ -0,0 +1,15 @@
+package com.thealgorithms.bitmanipulation;
+
+public final class BitSwap {
+    private BitSwap() {
+    }
+    /*
+     * @brief Swaps the bits at the position posA and posB from data
+     */
+    public static int bitSwap(int data, final int posA, final int posB) {
+        if (SingleBitOperations.getBit(data, posA) != SingleBitOperations.getBit(data, posB)) {
+            data ^= (1 << posA) ^ (1 << posB);
+        }
+        return data;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java b/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java
new file mode 100644
index 000000000000..40de770e0c66
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java
@@ -0,0 +1,13 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+public class BitSwapTest {
+    @Test
+    void testHighestSetBit() {
+        assertEquals(3, BitSwap.bitSwap(3, 0, 1));
+        assertEquals(5, BitSwap.bitSwap(6, 0, 1));
+        assertEquals(7, BitSwap.bitSwap(7, 1, 1));
+    }
+}

From 8002137b764de30918bfc1375fd816034edc3f16 Mon Sep 17 00:00:00 2001
From: Ayoub Chegraoui <ayoubch807@gmail.com>
Date: Sun, 15 Oct 2023 15:02:24 +0100
Subject: [PATCH 0050/1338] Fixed some typos and links for javadoc, and some
 refactoring (#4755)

---
 .../com/thealgorithms/ciphers/AESEncryption.java     |  2 +-
 .../thealgorithms/conversions/AnyBaseToDecimal.java  |  2 +-
 .../thealgorithms/conversions/DecimalToAnyBase.java  |  2 +-
 .../thealgorithms/conversions/RgbHsvConversion.java  |  4 ++--
 .../java/com/thealgorithms/geometry/GrahamScan.java  | 12 +++++-------
 5 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/AESEncryption.java b/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
index 2b12aeaa0466..169fc10e5269 100644
--- a/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
+++ b/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
@@ -19,7 +19,7 @@ public class AESEncryption {
 
     /**
      * 1. Generate a plain text for encryption 2. Get a secret key (printed in
-     * hexadecimal form). In actual use this must by encrypted and kept safe.
+     * hexadecimal form). In actual use this must be encrypted and kept safe.
      * The same key is required for decryption.
      */
     public static void main(String[] args) throws Exception {
diff --git a/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java b/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java
index 837b35305c80..20f15bc2ff39 100644
--- a/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java
@@ -1,7 +1,7 @@
 package com.thealgorithms.conversions;
 
 /**
- * @author Varun Upadhyay (https://github.com/varunu28)
+ * @author Varun Upadhyay (<a href="https://github.com/varunu28">...</a>)
  */
 // Driver program
 public class AnyBaseToDecimal {
diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java b/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java
index 31ef2bffb708..2d0223a4c448 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java
@@ -5,7 +5,7 @@
 import java.util.ArrayList;
 
 /**
- * @author Varun Upadhyay (https://github.com/varunu28)
+ * @author Varun Upadhyay (<a href="https://github.com/varunu28">...</a>)
  */
 // Driver Program
 public class DecimalToAnyBase {
diff --git a/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java b/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java
index ca64c3ffd7a6..65cb00fc0ad0 100644
--- a/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java
+++ b/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java
@@ -10,8 +10,8 @@
  * models how colors appear under light. In it, colors are represented using
  * three components: hue, saturation and (brightness-)value. This class provides
  * methods for converting colors from one representation to the other.
- * (description adapted from https://en.wikipedia.org/wiki/RGB_color_model and
- * https://en.wikipedia.org/wiki/HSL_and_HSV).
+ * (description adapted from <a href="https://en.wikipedia.org/wiki/RGB_color_model">[1]</a> and
+ * <a href="https://en.wikipedia.org/wiki/HSL_and_HSV">[2]</a>).
  */
 public class RgbHsvConversion {
 
diff --git a/src/main/java/com/thealgorithms/geometry/GrahamScan.java b/src/main/java/com/thealgorithms/geometry/GrahamScan.java
index 3325a65829e0..9122c6f6f3cc 100644
--- a/src/main/java/com/thealgorithms/geometry/GrahamScan.java
+++ b/src/main/java/com/thealgorithms/geometry/GrahamScan.java
@@ -6,7 +6,7 @@
 
 /*
  * A Java program that computes the convex hull using the Graham Scan algorithm
- * In the best case, time complexity is O(n), while in the worst case, it is log(n).
+ * In the best case, time complexity is O(n), while in the worst case, it is O(nlog(n)).
  * O(n) space complexity
  *
  * This algorithm is only applicable to integral coordinates.
@@ -106,16 +106,14 @@ public static int orientation(Point a, Point b, Point c) {
 
         /**
          * @param p2 Co-ordinate of point to compare to.
-         * This function will compare the points and will return a positive integer it the
+         * This function will compare the points and will return a positive integer if the
          * point is greater than the argument point and a negative integer if the point is
          * less than the argument point.
          */
         public int compareTo(Point p2) {
-            if (this.y < p2.y) return -1;
-            if (this.y > p2.y) return +1;
-            if (this.x < p2.x) return -1;
-            if (this.x > p2.x) return +1;
-            return 0;
+            int res = Integer.compare(this.y, p2.y);
+            if (res == 0) res = Integer.compare(this.x, p2.x);
+            return res;
         }
 
         /**

From f3345d9e06dd39c730ad960ef6f4f8dbf73041b3 Mon Sep 17 00:00:00 2001
From: ironspec07 <127649008+ironspec07@users.noreply.github.com>
Date: Fri, 20 Oct 2023 00:32:27 +0530
Subject: [PATCH 0051/1338] Fixed typo error for better readability (#4835)

---
 src/main/java/com/thealgorithms/misc/ColorContrastRatio.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java b/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java
index f7767d54a0aa..2d8371a9a53d 100644
--- a/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java
+++ b/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java
@@ -3,7 +3,7 @@
 import java.awt.Color;
 
 /**
- * @brief A Java implementation of the offcial W3 documented procedure to
+ * @brief A Java implementation of the official W3 documented procedure to
  * calculate contrast ratio between colors on the web. This is used to calculate
  * the readability of a foreground color on top of a background color.
  * @since 2020-10-15

From e87036d886f2a3e477053bde76d5567f21615dd7 Mon Sep 17 00:00:00 2001
From: Aditi Bansal <142652964+Aditi22Bansal@users.noreply.github.com>
Date: Fri, 20 Oct 2023 01:07:29 +0530
Subject: [PATCH 0052/1338] Correct documentation of `IsEven` (#4845)

* Update IsEven.java

* Update IsEven.java

* Update IsEven.java

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 src/main/java/com/thealgorithms/bitmanipulation/IsEven.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java b/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java
index ec30eb09168b..b6bdc25fcc2b 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java
@@ -1,7 +1,7 @@
 package com.thealgorithms.bitmanipulation;
 
 /**
- * Converts any Octal Number to a Binary Number
+ * Checks whether a number is even
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
 

From 9dae389faa03b8400b6f0796383f47495887151a Mon Sep 17 00:00:00 2001
From: Appari Satya Barghav <36763910+satyabarghav@users.noreply.github.com>
Date: Tue, 24 Oct 2023 02:39:42 +0530
Subject: [PATCH 0053/1338] Herons : Changed the signature of the function
 (#4686)

* Made changes to the code to correct the Logic of Armstrong Number

* Resolved the issues

* Trying to resolve the Linter error by changing Variable name

* Changed Variable Names : trying to resolve Clang error

* Chnged the signature of the function

* Added the Function documentation

* Added exception for parameters

* Resolved with suggested changes

* Resolved with Suggested changes

* fix: use proper logic

---------

Co-authored-by: vil02 <vil02@o2.pl>
---
 .../thealgorithms/maths/HeronsFormula.java    | 35 ++++++++++++++-----
 .../maths/HeronsFormulaTest.java              | 20 ++++++++---
 2 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/HeronsFormula.java b/src/main/java/com/thealgorithms/maths/HeronsFormula.java
index 72052a1b8d45..5baee715d1ec 100644
--- a/src/main/java/com/thealgorithms/maths/HeronsFormula.java
+++ b/src/main/java/com/thealgorithms/maths/HeronsFormula.java
@@ -1,18 +1,35 @@
 package com.thealgorithms.maths;
 
 /**
+ * Wikipedia for HeronsFormula => https://en.wikipedia.org/wiki/Heron%27s_formula
  * Find the area of a triangle using only side lengths
  */
 
-public class HeronsFormula {
+public final class HeronsFormula {
 
-    public static double Herons(int s1, int s2, int s3) {
-        double a = s1;
-        double b = s2;
-        double c = s3;
-        double s = (a + b + c) / 2.0;
-        double area = 0;
-        area = Math.sqrt((s) * (s - a) * (s - b) * (s - c));
-        return area;
+    /*
+     * A function to get the Area of a Triangle using Heron's Formula
+     * @param s1,s2,s3 => the three sides of the Triangle
+     * @return area using the formula (√(s(s – s1)(s – s2)(s – s3)))
+     * here s is called semi-perimeter and it is the half of the perimeter (i.e; s = (s1+s2+s3)/2)
+     * @author satyabarghav
+     */
+    private HeronsFormula() {
+    }
+
+    private static boolean areAllSidesPositive(final double a, final double b, final double c) {
+        return a > 0 && b > 0 && c > 0;
+    }
+
+    private static boolean canFormTriangle(final double a, final double b, final double c) {
+        return a + b > c && b + c > a && c + a > b;
+    }
+
+    public static double herons(final double a, final double b, final double c) {
+        if (!areAllSidesPositive(a, b, c) || !canFormTriangle(a, b, c)) {
+            throw new IllegalArgumentException("Triangle can't be formed with the given side lengths");
+        }
+        final double s = (a + b + c) / 2.0;
+        return Math.sqrt((s) * (s - a) * (s - b) * (s - c));
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java b/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java
index 32feeacdb916..22cecf4dc960 100644
--- a/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java
+++ b/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java
@@ -7,21 +7,33 @@ public class HeronsFormulaTest {
 
     @Test
     void test1() {
-        Assertions.assertEquals(HeronsFormula.Herons(3, 4, 5), 6.0);
+        Assertions.assertEquals(HeronsFormula.herons(3, 4, 5), 6.0);
     }
 
     @Test
     void test2() {
-        Assertions.assertEquals(HeronsFormula.Herons(24, 30, 18), 216.0);
+        Assertions.assertEquals(HeronsFormula.herons(24, 30, 18), 216.0);
     }
 
     @Test
     void test3() {
-        Assertions.assertEquals(HeronsFormula.Herons(1, 1, 1), 0.4330127018922193);
+        Assertions.assertEquals(HeronsFormula.herons(1, 1, 1), 0.4330127018922193);
     }
 
     @Test
     void test4() {
-        Assertions.assertEquals(HeronsFormula.Herons(4, 5, 8), 8.181534085976786);
+        Assertions.assertEquals(HeronsFormula.herons(4, 5, 8), 8.181534085976786);
+    }
+
+    @Test
+    public void testCalculateAreaWithInvalidInput() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 2, 3); });
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(2, 1, 3); });
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(3, 2, 1); });
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 3, 2); });
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 1, 0); });
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 0, 1); });
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(0, 1, 1); });
     }
 }

From a4711d61d87cf75bf68f1f0b25345b1439220acf Mon Sep 17 00:00:00 2001
From: Aakil Iqbal <62759233+aakiliqbal@users.noreply.github.com>
Date: Wed, 25 Oct 2023 09:30:18 +0530
Subject: [PATCH 0054/1338] Added MapReduce Algorithm in Misc Folder. (#4828)

* Added MapReduce Algorithm in Misc Folder.

* Did formatting correctly

* Removed main function and added MapReduceTest

* format the code
---
 .../com/thealgorithms/misc/MapReduce.java     | 39 +++++++++++++++++++
 .../com/thealgorithms/misc/MapReduceTest.java | 23 +++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/misc/MapReduce.java
 create mode 100644 src/test/java/com/thealgorithms/misc/MapReduceTest.java

diff --git a/src/main/java/com/thealgorithms/misc/MapReduce.java b/src/main/java/com/thealgorithms/misc/MapReduce.java
new file mode 100644
index 000000000000..baf960f8ecef
--- /dev/null
+++ b/src/main/java/com/thealgorithms/misc/MapReduce.java
@@ -0,0 +1,39 @@
+package com.thealgorithms.misc;
+
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+/*
+* MapReduce is a programming model for processing and generating large data sets with a parallel,
+distributed algorithm on a cluster.
+* It has two main steps: the Map step, where the data is divided into smaller chunks and processed in parallel,
+and the Reduce step, where the results from the Map step are combined to produce the final output.
+* Wikipedia link : https://en.wikipedia.org/wiki/MapReduce
+*/
+
+public class MapReduce {
+    /*
+     *Counting all the words frequency within a sentence.
+     */
+    public static String mapreduce(String sentence) {
+        List<String> wordList = Arrays.stream(sentence.split(" ")).toList();
+
+        // Map step
+        Map<String, Long> wordCounts = wordList.stream().collect(Collectors.groupingBy(Function.identity(), LinkedHashMap::new, Collectors.counting()));
+
+        // Reduce step
+        StringBuilder result = new StringBuilder();
+        wordCounts.forEach((word, count) -> result.append(word).append(": ").append(count).append(","));
+
+        // Removing the last ',' if it exists
+        if (!result.isEmpty()) {
+            result.setLength(result.length() - 1);
+        }
+
+        return result.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/misc/MapReduceTest.java b/src/test/java/com/thealgorithms/misc/MapReduceTest.java
new file mode 100644
index 000000000000..213acad9743b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/MapReduceTest.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class MapReduceTest {
+    @Test
+    public void testMapReduceWithSingleWordSentence() {
+        String oneWordSentence = "Hactober";
+        String result = MapReduce.mapreduce(oneWordSentence);
+
+        assertEquals("Hactober: 1", result);
+    }
+
+    @Test
+    public void testMapReduceWithMultipleWordSentence() {
+        String multipleWordSentence = "I Love Love HactoberFest";
+        String result = MapReduce.mapreduce(multipleWordSentence);
+
+        assertEquals("I: 1,Love: 2,HactoberFest: 1", result);
+    }
+}

From 9dde8a780832a29c508deb3382410e36f127fdf1 Mon Sep 17 00:00:00 2001
From: Anup Omkar <57665180+anupomkar@users.noreply.github.com>
Date: Wed, 25 Oct 2023 19:04:05 +0530
Subject: [PATCH 0055/1338] Add `MatrixRank` (#4571)

* feat: adding matrix rank algorithm

* fix: formatting

* fix: adding comments, refactor and handling edge cases

* refactor: minor refactor

* enhancement: check matrix validity

* refactor: minor refactor and fixes

* Update src/main/java/com/thealgorithms/maths/MatrixRank.java

* feat: add unit test to check if input matrix is not modified while calculating the rank

---------

Co-authored-by: Anup Omkar <anup_omkar@intuit.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Co-authored-by: Andrii Siriak <siryaka@gmail.com>
---
 .../com/thealgorithms/maths/MatrixRank.java   | 164 ++++++++++++++++++
 .../thealgorithms/maths/MatrixRankTest.java   |  45 +++++
 2 files changed, 209 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/MatrixRank.java
 create mode 100644 src/test/java/com/thealgorithms/maths/MatrixRankTest.java

diff --git a/src/main/java/com/thealgorithms/maths/MatrixRank.java b/src/main/java/com/thealgorithms/maths/MatrixRank.java
new file mode 100644
index 000000000000..7a628b92dccb
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/MatrixRank.java
@@ -0,0 +1,164 @@
+package com.thealgorithms.maths;
+
+/**
+ * This class provides a method to compute the rank of a matrix.
+ * In linear algebra, the rank of a matrix is the maximum number of linearly independent rows or columns in the matrix.
+ * For example, consider the following 3x3 matrix:
+ * 1 2 3
+ * 2 4 6
+ * 3 6 9
+ * Despite having 3 rows and 3 columns, this matrix only has a rank of 1 because all rows (and columns) are multiples of each other.
+ * It's a fundamental concept that gives key insights into the structure of the matrix.
+ * It's important to note that the rank is not only defined for square matrices but for any m x n matrix.
+ *
+ * @author Anup Omkar
+ */
+public final class MatrixRank {
+
+    private MatrixRank() {
+    }
+
+    private static final double EPSILON = 1e-10;
+
+    /**
+     * @brief Computes the rank of the input matrix
+     *
+     * @param matrix The input matrix
+     * @return The rank of the input matrix
+     */
+    public static int computeRank(double[][] matrix) {
+        validateInputMatrix(matrix);
+
+        int numRows = matrix.length;
+        int numColumns = matrix[0].length;
+        int rank = 0;
+
+        boolean[] rowMarked = new boolean[numRows];
+
+        double[][] matrixCopy = deepCopy(matrix);
+
+        for (int colIndex = 0; colIndex < numColumns; ++colIndex) {
+            int pivotRow = findPivotRow(matrixCopy, rowMarked, colIndex);
+            if (pivotRow != numRows) {
+                ++rank;
+                rowMarked[pivotRow] = true;
+                normalizePivotRow(matrixCopy, pivotRow, colIndex);
+                eliminateRows(matrixCopy, pivotRow, colIndex);
+            }
+        }
+        return rank;
+    }
+
+    private static boolean isZero(double value) {
+        return Math.abs(value) < EPSILON;
+    }
+
+    private static double[][] deepCopy(double[][] matrix) {
+        int numRows = matrix.length;
+        int numColumns = matrix[0].length;
+        double[][] matrixCopy = new double[numRows][numColumns];
+        for (int rowIndex = 0; rowIndex < numRows; ++rowIndex) {
+            System.arraycopy(matrix[rowIndex], 0, matrixCopy[rowIndex], 0, numColumns);
+        }
+        return matrixCopy;
+    }
+
+    private static void validateInputMatrix(double[][] matrix) {
+        if (matrix == null) {
+            throw new IllegalArgumentException("The input matrix cannot be null");
+        }
+        if (matrix.length == 0) {
+            throw new IllegalArgumentException("The input matrix cannot be empty");
+        }
+        if (!hasValidRows(matrix)) {
+            throw new IllegalArgumentException("The input matrix cannot have null or empty rows");
+        }
+        if (isJaggedMatrix(matrix)) {
+            throw new IllegalArgumentException("The input matrix cannot be jagged");
+        }
+    }
+
+    private static boolean hasValidRows(double[][] matrix) {
+        for (double[] row : matrix) {
+            if (row == null || row.length == 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * @brief Checks if the input matrix is a jagged matrix.
+     * Jagged matrix is a matrix where the number of columns in each row is not the same.
+     *
+     * @param matrix The input matrix
+     * @return True if the input matrix is a jagged matrix, false otherwise
+     */
+    private static boolean isJaggedMatrix(double[][] matrix) {
+        int numColumns = matrix[0].length;
+        for (double[] row : matrix) {
+            if (row.length != numColumns) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * @brief The pivot row is the row in the matrix that is used to eliminate other rows and reduce the matrix to its row echelon form.
+     * The pivot row is selected as the first row (from top to bottom) where the value in the current column (the pivot column) is not zero.
+     * This row is then used to "eliminate" other rows, by subtracting multiples of the pivot row from them, so that all other entries in the pivot column become zero.
+     * This process is repeated for each column, each time selecting a new pivot row, until the matrix is in row echelon form.
+     * The number of pivot rows (rows with a leading entry, or pivot) then gives the rank of the matrix.
+     *
+     * @param matrix The input matrix
+     * @param rowMarked An array indicating which rows have been marked
+     * @param colIndex The column index
+     * @return The pivot row index, or the number of rows if no suitable pivot row was found
+     */
+    private static int findPivotRow(double[][] matrix, boolean[] rowMarked, int colIndex) {
+        int numRows = matrix.length;
+        for (int pivotRow = 0; pivotRow < numRows; ++pivotRow) {
+            if (!rowMarked[pivotRow] && !isZero(matrix[pivotRow][colIndex])) {
+                return pivotRow;
+            }
+        }
+        return numRows;
+    }
+
+    /**
+     * @brief This method divides all values in the pivot row by the value in the given column.
+     * This ensures that the pivot value itself will be 1, which simplifies further calculations.
+     *
+     * @param matrix The input matrix
+     * @param pivotRow The pivot row index
+     * @param colIndex The column index
+     */
+    private static void normalizePivotRow(double[][] matrix, int pivotRow, int colIndex) {
+        int numColumns = matrix[0].length;
+        for (int nextCol = colIndex + 1; nextCol < numColumns; ++nextCol) {
+            matrix[pivotRow][nextCol] /= matrix[pivotRow][colIndex];
+        }
+    }
+
+    /**
+     * @brief This method subtracts multiples of the pivot row from all other rows,
+     * so that all values in the given column of other rows will be zero.
+     * This is a key step in reducing the matrix to row echelon form.
+     *
+     * @param matrix The input matrix
+     * @param pivotRow The pivot row index
+     * @param colIndex The column index
+     */
+    private static void eliminateRows(double[][] matrix, int pivotRow, int colIndex) {
+        int numRows = matrix.length;
+        int numColumns = matrix[0].length;
+        for (int otherRow = 0; otherRow < numRows; ++otherRow) {
+            if (otherRow != pivotRow && !isZero(matrix[otherRow][colIndex])) {
+                for (int col2 = colIndex + 1; col2 < numColumns; ++col2) {
+                    matrix[otherRow][col2] -= matrix[pivotRow][col2] * matrix[otherRow][colIndex];
+                }
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/MatrixRankTest.java b/src/test/java/com/thealgorithms/maths/MatrixRankTest.java
new file mode 100644
index 000000000000..415b84ec43f8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/MatrixRankTest.java
@@ -0,0 +1,45 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.Arrays;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class MatrixRankTest {
+
+    private static Stream<Arguments> validInputStream() {
+        return Stream.of(Arguments.of(3, new double[][] {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}), Arguments.of(0, new double[][] {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}), Arguments.of(1, new double[][] {{1}}), Arguments.of(2, new double[][] {{1, 2}, {3, 4}}),
+            Arguments.of(2, new double[][] {{3, -1, 2}, {-3, 1, 2}, {-6, 2, 4}}), Arguments.of(3, new double[][] {{2, 3, 0, 1}, {1, 0, 1, 2}, {-1, 1, 1, -2}, {1, 5, 3, -1}}), Arguments.of(1, new double[][] {{1, 2, 3}, {3, 6, 9}}),
+            Arguments.of(2, new double[][] {{0.25, 0.5, 0.75, 2}, {1.5, 3, 4.5, 6}, {1, 2, 3, 4}}));
+    }
+
+    private static Stream<Arguments> invalidInputStream() {
+        return Stream.of(Arguments.of((Object) new double[][] {{1, 2}, {10}, {100, 200, 300}}), // jagged array
+            Arguments.of((Object) new double[][] {}), // empty matrix
+            Arguments.of((Object) new double[][] {{}, {}}), // empty row
+            Arguments.of((Object) null), // null matrix
+            Arguments.of((Object) new double[][] {{1, 2}, null}) // null row
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("validInputStream")
+    void computeRankTests(int expectedRank, double[][] matrix) {
+        int originalHashCode = Arrays.deepHashCode(matrix);
+        int rank = MatrixRank.computeRank(matrix);
+        int newHashCode = Arrays.deepHashCode(matrix);
+
+        assertEquals(expectedRank, rank);
+        assertEquals(originalHashCode, newHashCode);
+    }
+
+    @ParameterizedTest
+    @MethodSource("invalidInputStream")
+    void computeRankWithInvalidMatrix(double[][] matrix) {
+        assertThrows(IllegalArgumentException.class, () -> MatrixRank.computeRank(matrix));
+    }
+}

From 945e7b56bb186c3be908e02720e932b5ce834e01 Mon Sep 17 00:00:00 2001
From: Satvik Singh Sengar <satviksengar60@gmail.com>
Date: Mon, 30 Oct 2023 22:54:23 +0530
Subject: [PATCH 0056/1338] Fix:/Number of count of major element in Boyer
 Moore algorithm (#4728)

* Number of count of major element in Boyer Moore algorithm

* test: add `BoyerMooreTest`

* style: basic linting

* tests: add test case from the issue

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Co-authored-by: vil02 <vil02@o2.pl>
---
 .../com/thealgorithms/others/BoyerMoore.java  | 30 +++++++------------
 .../thealgorithms/others/BoyerMooreTest.java  | 22 ++++++++++++++
 2 files changed, 32 insertions(+), 20 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/BoyerMooreTest.java

diff --git a/src/main/java/com/thealgorithms/others/BoyerMoore.java b/src/main/java/com/thealgorithms/others/BoyerMoore.java
index 09235b521b44..d9d5b5d028ef 100644
--- a/src/main/java/com/thealgorithms/others/BoyerMoore.java
+++ b/src/main/java/com/thealgorithms/others/BoyerMoore.java
@@ -6,27 +6,28 @@
  */
 package com.thealgorithms.others;
 
-import java.util.*;
-
-public class BoyerMoore {
+public final class BoyerMoore {
+    private BoyerMoore() {
+    }
 
-    public static int findmajor(int[] a) {
+    public static int findmajor(final int[] a) {
         int count = 0;
         int cand = -1;
-        for (int i = 0; i < a.length; i++) {
+        for (final var k : a) {
             if (count == 0) {
-                cand = a[i];
+                cand = k;
                 count = 1;
             } else {
-                if (a[i] == cand) {
+                if (k == cand) {
                     count++;
                 } else {
                     count--;
                 }
             }
         }
-        for (int i = 0; i < a.length; i++) {
-            if (a[i] == cand) {
+        count = 0;
+        for (final var j : a) {
+            if (j == cand) {
                 count++;
             }
         }
@@ -35,15 +36,4 @@ public static int findmajor(int[] a) {
         }
         return -1;
     }
-
-    public static void main(String[] args) {
-        Scanner input = new Scanner(System.in);
-        int n = input.nextInt();
-        int[] a = new int[n];
-        for (int i = 0; i < n; i++) {
-            a[i] = input.nextInt();
-        }
-        System.out.println("the majority element is " + findmajor(a));
-        input.close();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/others/BoyerMooreTest.java b/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
new file mode 100644
index 000000000000..b614c14070bd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.others;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class BoyerMooreTest {
+
+    @ParameterizedTest
+    @MethodSource("inputStream")
+    void numberTests(int expected, int[] input) {
+        Assertions.assertEquals(expected, BoyerMoore.findmajor(input));
+    }
+
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of(5, new int[] {5, 5, 5, 2}), Arguments.of(10, new int[] {10, 10, 20}), Arguments.of(10, new int[] {10, 20, 10}), Arguments.of(10, new int[] {20, 10, 10}), Arguments.of(-1, new int[] {10, 10, 20, 20, 30, 30}), Arguments.of(4, new int[] {1, 4, 2, 4, 4, 5, 4}));
+    }
+}

From e5f3d232c9fb97ed350a57708fc29d30fa0b28ae Mon Sep 17 00:00:00 2001
From: Phuong Nguyen <nhphuong.code@gmail.com>
Date: Tue, 31 Oct 2023 05:09:43 +0700
Subject: [PATCH 0057/1338] refactor: use method `SortUtils.swap` (#4946)

* refactor: use method SortUtils.swap

* fix: clang format

* style: explicitly import `swap`

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 src/main/java/com/thealgorithms/sorts/SelectionSort.java | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSort.java b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
index 555b4b6037dc..e43df7fe622e 100644
--- a/src/main/java/com/thealgorithms/sorts/SelectionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.sorts;
 
+import static com.thealgorithms.sorts.SortUtils.swap;
+
 public class SelectionSort implements SortAlgorithm {
 
     /**
@@ -20,9 +22,7 @@ public <T extends Comparable<T>> T[] sort(T[] arr) {
                 }
             }
             if (minIndex != i) {
-                T temp = arr[i];
-                arr[i] = arr[minIndex];
-                arr[minIndex] = temp;
+                swap(arr, i, minIndex);
             }
         }
         return arr;

From d086afce09a7de8d64332cc41015d3cf00e90cee Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 31 Oct 2023 03:48:05 +0530
Subject: [PATCH 0058/1338] Enhance code density and readability (#4914)

* Enhance code density and readability

* Add wiki link

---------

Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 .../divideandconquer/BinaryExponentiation.java         | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java b/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java
index da45d5b90cae..a70b16b0d069 100644
--- a/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java
+++ b/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java
@@ -2,6 +2,8 @@
 
 // Java Program to Implement Binary Exponentiation (power in log n)
 
+// Reference Link: https://en.wikipedia.org/wiki/Exponentiation_by_squaring
+
 /*
  * Binary Exponentiation is a method to calculate a to the power of b.
  * It is used to calculate a^n in O(log n) time.
@@ -14,14 +16,14 @@ public class BinaryExponentiation {
 
     // recursive function to calculate a to the power of b
     public static long calculatePower(long x, long y) {
+        // Base Case
         if (y == 0) {
             return 1;
         }
-        long val = calculatePower(x, y / 2);
-        if (y % 2 == 0) {
-            return val * val;
+        if (y % 2 == 1) { // odd power
+            return x * calculatePower(x, y - 1);
         }
-        return val * val * x;
+        return calculatePower(x * x, y / 2); // even power
     }
 
     // iterative function to calculate a to the power of b

From 574138c7a35351a0837bb4bd56e2eb295064b690 Mon Sep 17 00:00:00 2001
From: Prathamesh Powar <ppowar1910@gmail.com>
Date: Tue, 31 Oct 2023 13:37:59 +0530
Subject: [PATCH 0059/1338] Cleanup `BoyerMoore` (#4951)

* modify code to make use of java Optional class

* revert changes

* add java.util.Optional<Integer>

* add java.util.Optional

* refactors: make `findmajor` return `optional`

* refactors: make method name findMajor and split it

* refactors: change method name in tests

* Apply suggestions from code review

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* change back to int

* fix: swap arguments

* tests: add some test cases

* refactor: add `isMajority` and avoid rounding

* style: use `var`

* style: swap arguments of `countOccurrences`

---------

Co-authored-by: vil02 <vil02@o2.pl>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/others/BoyerMoore.java  | 35 +++++++++++++------
 .../thealgorithms/others/BoyerMooreTest.java  | 20 ++++++++---
 2 files changed, 40 insertions(+), 15 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/BoyerMoore.java b/src/main/java/com/thealgorithms/others/BoyerMoore.java
index d9d5b5d028ef..e67427deda79 100644
--- a/src/main/java/com/thealgorithms/others/BoyerMoore.java
+++ b/src/main/java/com/thealgorithms/others/BoyerMoore.java
@@ -5,35 +5,50 @@
 https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_majority_vote_algorithm
  */
 package com.thealgorithms.others;
+import java.util.Optional;
 
 public final class BoyerMoore {
     private BoyerMoore() {
     }
 
-    public static int findmajor(final int[] a) {
+    public static Optional<Integer> findMajor(final int[] a) {
+        final var candidate = findCandidate(a);
+        final var count = countOccurrences(candidate, a);
+        if (isMajority(count, a.length)) {
+            return Optional.of(candidate);
+        }
+        return Optional.empty();
+    }
+
+    private static int findCandidate(final int[] a) {
         int count = 0;
-        int cand = -1;
+        int candidate = -1;
         for (final var k : a) {
             if (count == 0) {
-                cand = k;
+                candidate = k;
                 count = 1;
             } else {
-                if (k == cand) {
+                if (k == candidate) {
                     count++;
                 } else {
                     count--;
                 }
             }
         }
-        count = 0;
+        return candidate;
+    }
+
+    private static int countOccurrences(final int candidate, final int[] a) {
+        int count = 0;
         for (final var j : a) {
-            if (j == cand) {
+            if (j == candidate) {
                 count++;
             }
         }
-        if (count > (a.length / 2)) {
-            return cand;
-        }
-        return -1;
+        return count;
+    }
+
+    private static boolean isMajority(final int count, final int totalCount) {
+        return 2 * count > totalCount;
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/BoyerMooreTest.java b/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
index b614c14070bd..b1497f7bc525 100644
--- a/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
+++ b/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
@@ -11,12 +11,22 @@
 public class BoyerMooreTest {
 
     @ParameterizedTest
-    @MethodSource("inputStream")
-    void numberTests(int expected, int[] input) {
-        Assertions.assertEquals(expected, BoyerMoore.findmajor(input));
+    @MethodSource("inputStreamWithExistingMajority")
+    void checkWhenMajorityExists(int expected, int[] input) {
+        Assertions.assertEquals(expected, BoyerMoore.findMajor(input).get());
     }
 
-    private static Stream<Arguments> inputStream() {
-        return Stream.of(Arguments.of(5, new int[] {5, 5, 5, 2}), Arguments.of(10, new int[] {10, 10, 20}), Arguments.of(10, new int[] {10, 20, 10}), Arguments.of(10, new int[] {20, 10, 10}), Arguments.of(-1, new int[] {10, 10, 20, 20, 30, 30}), Arguments.of(4, new int[] {1, 4, 2, 4, 4, 5, 4}));
+    private static Stream<Arguments> inputStreamWithExistingMajority() {
+        return Stream.of(Arguments.of(5, new int[] {5, 5, 5, 2}), Arguments.of(10, new int[] {10, 10, 20}), Arguments.of(10, new int[] {10, 20, 10}), Arguments.of(10, new int[] {20, 10, 10}), Arguments.of(4, new int[] {1, 4, 2, 4, 4, 5, 4}), Arguments.of(-1, new int[] {-1}));
+    }
+
+    @ParameterizedTest
+    @MethodSource("inputStreamWithoutMajority")
+    void checkWhenMajorityExists(int[] input) {
+        Assertions.assertFalse(BoyerMoore.findMajor(input).isPresent());
+    }
+
+    private static Stream<Arguments> inputStreamWithoutMajority() {
+        return Stream.of(Arguments.of(new int[] {10, 10, 20, 20, 30, 30}), Arguments.of(new int[] {10, 20, 30, 40, 50}), Arguments.of(new int[] {1, 2}), Arguments.of(new int[] {}));
     }
 }

From c527dff92da2046b850ffe9a3b8d0c2aae15d588 Mon Sep 17 00:00:00 2001
From: "D.Sunil" <sunilnitdgp5@gmail.com>
Date: Sun, 12 Nov 2023 02:25:48 +0530
Subject: [PATCH 0060/1338] Add Javadoc comments (#4745)

---
 .../dynamicprogramming/RodCutting.java        | 37 +++++++++++--------
 1 file changed, 21 insertions(+), 16 deletions(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java b/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
index 28ff41d1a2d1..4583aec2e1b4 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
@@ -1,32 +1,37 @@
 package com.thealgorithms.dynamicprogramming;
 
 /**
- * A DynamicProgramming solution for Rod cutting problem Returns the best
- * obtainable price for a rod of length n and price[] as prices of different
- * pieces
+ * A Dynamic Programming solution for the Rod cutting problem.
+ * Returns the best obtainable price for a rod of length n and price[] as prices of different pieces.
  */
 public class RodCutting {
 
-    private static int cutRod(int[] price, int n) {
+    /**
+     * This method calculates the maximum obtainable value for cutting a rod of length n
+     * into different pieces, given the prices for each possible piece length.
+     *
+     * @param price An array representing the prices of different pieces, where price[i-1]
+     *              represents the price of a piece of length i.
+     * @param n     The length of the rod to be cut.
+     * @return The maximum obtainable value.
+     */
+    public static int cutRod(int[] price, int n) {
+        // Create an array to store the maximum obtainable values for each rod length.
         int[] val = new int[n + 1];
         val[0] = 0;
 
+        // Calculate the maximum value for each rod length from 1 to n.
         for (int i = 1; i <= n; i++) {
-            int max_val = Integer.MIN_VALUE;
-            for (int j = 0; j < i; j++) {
-                max_val = Math.max(max_val, price[j] + val[i - j - 1]);
+            int maxVal = Integer.MIN_VALUE;
+            // Try all possible ways to cut the rod and find the maximum value.
+            for (int j = 1; j <= i; j++) {
+                maxVal = Math.max(maxVal, price[j - 1] + val[i - j]);
             }
-
-            val[i] = max_val;
+            // Store the maximum value for the current rod length.
+            val[i] = maxVal;
         }
 
+        // The final element of 'val' contains the maximum obtainable value for a rod of length 'n'.
         return val[n];
     }
-
-    // main function to test
-    public static void main(String[] args) {
-        int[] arr = new int[] {2, 5, 13, 19, 20};
-        int result = cutRod(arr, arr.length);
-        System.out.println("Maximum Obtainable Value is " + result);
-    }
 }

From b1efd4e34bb18a618ab205c9c2a62802f151c70d Mon Sep 17 00:00:00 2001
From: Niklas Hoefflin <122729995+itakurah@users.noreply.github.com>
Date: Fri, 24 Nov 2023 18:13:44 +0100
Subject: [PATCH 0061/1338] Add G-Counter (Grow-only Counter) (#4965)

---
 .../datastructures/crdt/GCounter.java         | 84 +++++++++++++++++++
 .../datastructures/crdt/GCounterTest.java     | 54 ++++++++++++
 2 files changed, 138 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java b/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java
new file mode 100644
index 000000000000..63364f858ec5
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java
@@ -0,0 +1,84 @@
+package com.thealgorithms.datastructures.crdt;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * G-Counter (Grow-only Counter) is a state-based CRDT (Conflict-free Replicated Data Type)
+ * designed for tracking counts in a distributed and concurrent environment.
+ * Each process maintains its own counter, allowing only increments. The total count
+ * is obtained by summing individual process counts.
+ * This implementation supports incrementing, querying the total count,
+ * comparing with other G-Counters, and merging with another G-Counter
+ * to compute the element-wise maximum.
+ * (https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type)
+ *
+ * @author itakurah (https://github.com/itakurah)
+ */
+
+class GCounter {
+    private final Map<Integer, Integer> P;
+    private final int myId;
+    private final int n;
+
+    /**
+     * Constructs a G-Counter for a cluster of n nodes.
+     *
+     * @param n The number of nodes in the cluster.
+     */
+    public GCounter(int myId, int n) {
+        this.myId = myId;
+        this.n = n;
+        this.P = new HashMap<>();
+
+        for (int i = 0; i < n; i++) {
+            P.put(i, 0);
+        }
+    }
+
+    /**
+     * Increments the counter for the current node.
+     */
+    public void increment() {
+        P.put(myId, P.get(myId) + 1);
+    }
+
+    /**
+     * Gets the total value of the counter by summing up values from all nodes.
+     *
+     * @return The total value of the counter.
+     */
+    public int value() {
+        int sum = 0;
+        for (int v : P.values()) {
+            sum += v;
+        }
+        return sum;
+    }
+
+    /**
+     * Compares the state of this G-Counter with another G-Counter.
+     *
+     * @param other The other G-Counter to compare with.
+     * @return True if the state of this G-Counter is less than or equal to the state of the other G-Counter.
+     */
+    public boolean compare(GCounter other) {
+        for (int i = 0; i < n; i++) {
+            if (this.P.get(i) > other.P.get(i)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Merges the state of this G-Counter with another G-Counter.
+     *
+     * @param other The other G-Counter to merge with.
+     */
+    public void merge(GCounter other) {
+        for (int i = 0; i < n; i++) {
+            this.P.put(i, Math.max(this.P.get(i), other.P.get(i)));
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java
new file mode 100644
index 000000000000..f931e602383c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.datastructures.crdt;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class GCounterTest {
+    @Test
+    void increment() {
+        GCounter counter = new GCounter(0, 3);
+        counter.increment();
+        counter.increment();
+        counter.increment();
+        assertEquals(3, counter.value());
+    }
+
+    @Test
+    void merge() {
+        GCounter counter1 = new GCounter(0, 3);
+        counter1.increment();
+        GCounter counter2 = new GCounter(1, 3);
+        counter2.increment();
+        counter2.increment();
+        GCounter counter3 = new GCounter(2, 3);
+        counter3.increment();
+        counter3.increment();
+        counter3.increment();
+        counter1.merge(counter2);
+        counter1.merge(counter3);
+        counter2.merge(counter1);
+        counter3.merge(counter2);
+        assertEquals(6, counter1.value());
+        assertEquals(6, counter2.value());
+        assertEquals(6, counter3.value());
+    }
+
+    @Test
+    void compare() {
+        GCounter counter1 = new GCounter(0, 5);
+        GCounter counter2 = new GCounter(3, 5);
+        counter1.increment();
+        counter1.increment();
+        counter2.merge(counter1);
+        counter2.increment();
+        counter2.increment();
+        assertTrue(counter1.compare(counter2));
+        counter1.increment();
+        counter2.increment();
+        counter2.merge(counter1);
+        assertTrue(counter1.compare(counter2));
+        counter1.increment();
+        assertFalse(counter1.compare(counter2));
+    }
+}

From 1518e84fb961f988b35ef402ec25a6576879c7ff Mon Sep 17 00:00:00 2001
From: Doksanbir <ylcn91@users.noreply.github.com>
Date: Sun, 26 Nov 2023 14:34:13 +0300
Subject: [PATCH 0062/1338] Add Tribonacci Numbers (fixes #4646) (#4959)

---
 .../dynamicprogramming/Tribonacci.java        | 30 +++++++++++++++++++
 .../dynamicprogramming/TribonacciTest.java    | 24 +++++++++++++++
 2 files changed, 54 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java b/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
new file mode 100644
index 000000000000..99f9029009ab
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
@@ -0,0 +1,30 @@
+package com.thealgorithms.dynamicprogramming;
+
+/**
+ * The {@code Tribonacci} class provides a method to compute the n-th number in the Tribonacci sequence.
+ * N-th Tribonacci Number - https://leetcode.com/problems/n-th-tribonacci-number/description/
+ */
+public class Tribonacci {
+
+    /**
+     * Computes the n-th Tribonacci number.
+     *
+     * @param n the index of the Tribonacci number to compute
+     * @return the n-th Tribonacci number
+     */
+    public static int compute(int n) {
+        if (n == 0) return 0;
+        if (n == 1 || n == 2) return 1;
+
+        int first = 0, second = 1, third = 1;
+
+        for (int i = 3; i <= n; i++) {
+            int next = first + second + third;
+            first = second;
+            second = third;
+            third = next;
+        }
+
+        return third;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java
new file mode 100644
index 000000000000..434a1825dfec
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java
@@ -0,0 +1,24 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for {@code Tribonacci}.
+ */
+public class TribonacciTest {
+
+    /**
+     * Tests the Tribonacci computation for a set of known values.
+     */
+    @Test
+    public void testKnownValues() {
+        assertEquals(0, Tribonacci.compute(0), "The 0th Tribonacci should be 0.");
+        assertEquals(1, Tribonacci.compute(1), "The 1st Tribonacci should be 1.");
+        assertEquals(1, Tribonacci.compute(2), "The 2nd Tribonacci should be 1.");
+        assertEquals(2, Tribonacci.compute(3), "The 3rd Tribonacci should be 2.");
+        assertEquals(4, Tribonacci.compute(4), "The 4th Tribonacci should be 4.");
+        assertEquals(7, Tribonacci.compute(5), "The 5th Tribonacci should be 7.");
+    }
+}

From 3392b5116dc79f876a275539ec099b3d3a6894c6 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 28 Nov 2023 21:40:51 +0100
Subject: [PATCH 0063/1338] Add `codeql.yml` (#4966)

---
 .github/workflows/codeql.yml | 47 ++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 .github/workflows/codeql.yml

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
new file mode 100644
index 000000000000..482c8bc60527
--- /dev/null
+++ b/.github/workflows/codeql.yml
@@ -0,0 +1,47 @@
+---
+name: "CodeQL"
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - master
+  pull_request:
+  schedule:
+    - cron: '53 3 * * 0'
+
+env:
+  LANGUAGE: 'java-kotlin'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: 'ubuntu-latest'
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v3
+        with:
+          java-version: 17
+          distribution: 'adopt'
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v2
+        with:
+          languages: ${{ env.LANGUAGE }}
+
+      - name: Build
+        run: mvn --batch-mode --update-snapshots verify
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v2
+        with:
+          category: "/language:${{env.LANGUAGE}}"
+...

From 361b4108ee0ae7f5e5fde95121d4d5d91eae5c6a Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 29 Nov 2023 22:21:25 +0100
Subject: [PATCH 0064/1338] Use explicit cast to `int` in `FractionalKnapsack`
 (#4971)

---
 .../com/thealgorithms/greedyalgorithms/FractionalKnapsack.java  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java b/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
index c5570f35c004..f46364fc704b 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
@@ -32,7 +32,7 @@ public static int fractionalKnapsack(int weight[], int value[], int capacity) {
                 current -= weight[index];
             } else {
                 // If only a fraction of the item can fit, add a proportionate value.
-                finalValue += ratio[i][1] * current;
+                finalValue += (int) (ratio[i][1] * current);
                 break; // Stop adding items to the knapsack since it's full.
             }
         }

From f8de2901887a360ac3d2901b523f6b7e4df65e54 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 29 Nov 2023 22:30:59 +0100
Subject: [PATCH 0065/1338] Explicitly cast result of `Math.pow` to `int` in
 `BinaryToHexadecimal` (#4970)

---
 .../java/com/thealgorithms/conversions/BinaryToHexadecimal.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java b/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
index c942cbb7d843..011b60a952b8 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
@@ -34,7 +34,7 @@ static String binToHex(int binary) {
             for (i = 0; i < 4; i++) {
                 currbit = binary % 10;
                 binary = binary / 10;
-                code4 += currbit * Math.pow(2, i);
+                code4 += currbit * (int) Math.pow(2, i);
             }
             hex = hm.get(code4) + hex;
         }

From fc21a8bffe4398ba059c76f7968f43d150985103 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 30 Nov 2023 09:50:09 +0100
Subject: [PATCH 0066/1338] Explicitly cast result of `Math.pow` to `long` in
 `Armstrong` (#4972)

---
 src/main/java/com/thealgorithms/maths/Armstrong.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/maths/Armstrong.java b/src/main/java/com/thealgorithms/maths/Armstrong.java
index 526b31c3891f..ff4ae027a0b7 100644
--- a/src/main/java/com/thealgorithms/maths/Armstrong.java
+++ b/src/main/java/com/thealgorithms/maths/Armstrong.java
@@ -27,7 +27,7 @@ public boolean isArmstrong(int number) {
 
         while (originalNumber > 0) {
             long digit = originalNumber % 10;
-            sum += Math.pow(digit, power); // The digit raised to the power of the number of digits and added to the sum.
+            sum += (long) Math.pow(digit, power); // The digit raised to the power of the number of digits and added to the sum.
             originalNumber /= 10;
         }
 

From 9bebcee5c795dfc675196803b7d987ca3e4f9025 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 30 Nov 2023 17:36:31 +0100
Subject: [PATCH 0067/1338] Make `sumOfDigits` `long` in
 `HarshadNumber.isHarshad` (#4973)

fix: make `sumOfDigits` `long` in `HarshadNumber.isHarshad`
---
 src/main/java/com/thealgorithms/maths/HarshadNumber.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/maths/HarshadNumber.java b/src/main/java/com/thealgorithms/maths/HarshadNumber.java
index 854e4d555b40..4778dc81b664 100644
--- a/src/main/java/com/thealgorithms/maths/HarshadNumber.java
+++ b/src/main/java/com/thealgorithms/maths/HarshadNumber.java
@@ -15,7 +15,7 @@ public static boolean isHarshad(long n) {
         if (n <= 0) return false;
 
         long t = n;
-        int sumOfDigits = 0;
+        long sumOfDigits = 0;
         while (t > 0) {
             sumOfDigits += t % 10;
             t /= 10;

From e759544c333de9b98ff51458e1d71c69006f976b Mon Sep 17 00:00:00 2001
From: Niklas Hoefflin <122729995+itakurah@users.noreply.github.com>
Date: Sat, 2 Dec 2023 18:53:17 +0100
Subject: [PATCH 0068/1338] Add Boruvka's algorithm to find Minimum Spanning
 Tree (#4964)

---
 DIRECTORY.md                                  |  20 ++
 .../graphs/BoruvkaAlgorithm.java              | 217 ++++++++++++++++++
 .../graphs/BoruvkaAlgorithmTest.java          | 191 +++++++++++++++
 3 files changed, 428 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6de516618484..89f08c27248b 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -19,6 +19,7 @@
             * [PowerSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/PowerSum.java)
             * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
           * bitmanipulation
+            * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
             * [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
             * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
             * [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
@@ -81,6 +82,8 @@
               * [LFUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java)
               * [LRUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java)
               * [MRUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java)
+            * crdt
+              * [GCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java)
             * disjointsetunion
               * [DisjointSetUnion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java)
               * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/Node.java)
@@ -90,6 +93,7 @@
               * [A Star](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java)
               * [BellmanFord](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java)
               * [BipartiteGrapfDFS](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java)
+              * [BoruvkaAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithm.java)
               * [ConnectedComponent](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java)
               * [Cycles](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java)
               * [DIJSKSTRAS ALGORITHM](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java)
@@ -239,6 +243,7 @@
             * [SubsetCount](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java)
             * [SubsetSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java)
             * [Sum Of Subset](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Sum_Of_Subset.java)
+            * [Tribonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java)
             * [UniquePaths](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java)
             * [WildcardMatching](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java)
             * [WineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java)
@@ -281,7 +286,9 @@
             * [FFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FFT.java)
             * [FFTBluestein](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FFTBluestein.java)
             * [FibonacciJavaStreams](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java)
+            * [FibonacciLoop](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FibonacciLoop.java)
             * [FibonacciNumberCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java)
+            * [FibonacciNumberGoldenRation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java)
             * [FindKthNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FindKthNumber.java)
             * [FindMax](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FindMax.java)
             * [FindMaxRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java)
@@ -307,6 +314,7 @@
             * [LongDivision](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LongDivision.java)
             * [LucasSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LucasSeries.java)
             * [MagicSquare](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MagicSquare.java)
+            * [MatrixRank](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MatrixRank.java)
             * [MatrixUtil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MatrixUtil.java)
             * [MaxValue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MaxValue.java)
             * [Means](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Means.java)
@@ -359,6 +367,7 @@
           * misc
             * [ColorContrastRatio](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java)
             * [InverseOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java)
+            * [MapReduce](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MapReduce.java)
             * [matrixTranspose](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/matrixTranspose.java)
             * [MedianOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java)
             * [MedianOfRunningArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java)
@@ -564,6 +573,7 @@
             * [PowerSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PowerSumTest.java)
             * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
           * bitmanipulation
+            * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
             * [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
             * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
             * [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
@@ -605,9 +615,12 @@
               * [LFUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java)
               * [LRUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java)
               * [MRUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java)
+            * crdt
+              * [GCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java)
             * disjointsetunion
               * [DisjointSetUnionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java)
             * graphs
+              * [BoruvkaAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
               * [HamiltonianCycleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java)
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
               * [TarjansAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
@@ -666,6 +679,7 @@
             * [OptimalJobSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
             * [PartitionProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java)
             * [SubsetCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java)
+            * [TribonacciTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java)
             * [UniquePathsTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java)
             * [WildcardMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java)
           * geometry
@@ -700,7 +714,9 @@
             * [FastInverseSqrtTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java)
             * [FFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FFTTest.java)
             * [FibonacciJavaStreamsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciJavaStreamsTest.java)
+            * [FibonacciLoopTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciLoopTest.java)
             * [FibonacciNumberCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciNumberCheckTest.java)
+            * [FibonacciNumberGoldenRationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciNumberGoldenRationTest.java)
             * [FindMaxRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java)
             * [FindMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMaxTest.java)
             * [FindMinRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMinRecursionTest.java)
@@ -719,6 +735,7 @@
             * [LiouvilleLambdaFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java)
             * [LongDivisionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LongDivisionTest.java)
             * [LucasSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LucasSeriesTest.java)
+            * [MatrixRankTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MatrixRankTest.java)
             * [MaxValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MaxValueTest.java)
             * [MeansTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MeansTest.java)
             * [MedianTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MedianTest.java)
@@ -755,6 +772,7 @@
             * [TwinPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TwinPrimeTest.java)
             * [VolumeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/VolumeTest.java)
           * misc
+            * [MapReduceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MapReduceTest.java)
             * [MedianOfMatrixtest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java)
             * [MedianOfRunningArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java)
             * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java)
@@ -763,6 +781,7 @@
           * others
             * [ArrayLeftRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java)
             * [BestFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BestFitCPUTest.java)
+            * [BoyerMooreTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BoyerMooreTest.java)
             * cn
               * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java)
             * [ConwayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ConwayTest.java)
@@ -798,6 +817,7 @@
             * [HowManyTimesRotatedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java)
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
+            * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
             * [QuickSelectTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/QuickSelectTest.java)
             * [RabinKarpAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java)
             * [RecursiveBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithm.java
new file mode 100644
index 000000000000..dcdb08ad133e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithm.java
@@ -0,0 +1,217 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Boruvka's algorithm to find Minimum Spanning Tree
+ * (https://en.wikipedia.org/wiki/Bor%C5%AFvka%27s_algorithm)
+ *
+ * @author itakurah (https://github.com/itakurah)
+ */
+
+final class BoruvkaAlgorithm {
+    private BoruvkaAlgorithm() {
+    }
+
+    /**
+     * Represents an edge in the graph
+     */
+    static class Edge {
+        final int src;
+        final int dest;
+        final int weight;
+
+        Edge(final int src, final int dest, final int weight) {
+            this.src = src;
+            this.dest = dest;
+            this.weight = weight;
+        }
+    }
+
+    /**
+     * Represents the graph
+     */
+    static class Graph {
+        final int vertex;
+        final List<Edge> edges;
+
+        /**
+         * Constructor for the graph
+         *
+         * @param vertex number of vertices
+         * @param edges  list of edges
+         */
+        Graph(final int vertex, final List<Edge> edges) {
+            if (vertex < 0) {
+                throw new IllegalArgumentException("Number of vertices must be positive");
+            }
+            if (edges == null || edges.isEmpty()) {
+                throw new IllegalArgumentException("Edges list must not be null or empty");
+            }
+            for (final var edge : edges) {
+                checkEdgeVertices(edge.src, vertex);
+                checkEdgeVertices(edge.dest, vertex);
+            }
+
+            this.vertex = vertex;
+            this.edges = edges;
+        }
+    }
+
+    /**
+     * Represents a subset for Union-Find operations
+     */
+    private static class Component {
+        int parent;
+        int rank;
+
+        Component(final int parent, final int rank) {
+            this.parent = parent;
+            this.rank = rank;
+        }
+    }
+
+    /**
+     * Represents the state of Union-Find components and the result list
+     */
+    private static class BoruvkaState {
+        List<Edge> result;
+        Component[] components;
+        final Graph graph;
+
+        BoruvkaState(final Graph graph) {
+            this.result = new ArrayList<>();
+            this.components = initializeComponents(graph);
+            this.graph = graph;
+        }
+
+        /**
+         * Adds the cheapest edges to the result list and performs Union operation on the subsets.
+         *
+         * @param cheapest Array containing the cheapest edge for each subset.
+         */
+        void merge(final Edge[] cheapest) {
+            for (int i = 0; i < graph.vertex; ++i) {
+                if (cheapest[i] != null) {
+                    final var component1 = find(components, cheapest[i].src);
+                    final var component2 = find(components, cheapest[i].dest);
+
+                    if (component1 != component2) {
+                        result.add(cheapest[i]);
+                        union(components, component1, component2);
+                    }
+                }
+            }
+        }
+
+        /**
+         * Checks if there are more edges to add to the result list
+         *
+         * @return true if there are more edges to add, false otherwise
+         */
+        boolean hasMoreEdgesToAdd() {
+            return result.size() < graph.vertex - 1;
+        }
+
+        /**
+         * Computes the cheapest edges for each subset in the Union-Find structure.
+         *
+         * @return an array containing the cheapest edge for each subset.
+         */
+        private Edge[] computeCheapestEdges() {
+            Edge[] cheapest = new Edge[graph.vertex];
+            for (final var edge : graph.edges) {
+                final var set1 = find(components, edge.src);
+                final var set2 = find(components, edge.dest);
+
+                if (set1 != set2) {
+                    if (cheapest[set1] == null || edge.weight < cheapest[set1].weight) {
+                        cheapest[set1] = edge;
+                    }
+                    if (cheapest[set2] == null || edge.weight < cheapest[set2].weight) {
+                        cheapest[set2] = edge;
+                    }
+                }
+            }
+            return cheapest;
+        }
+
+        /**
+         * Initializes subsets for Union-Find
+         *
+         * @param graph the graph
+         * @return the initialized subsets
+         */
+        private static Component[] initializeComponents(final Graph graph) {
+            Component[] components = new Component[graph.vertex];
+            for (int v = 0; v < graph.vertex; ++v) {
+                components[v] = new Component(v, 0);
+            }
+            return components;
+        }
+    }
+
+    /**
+     * Finds the parent of the subset using path compression
+     *
+     * @param components array of subsets
+     * @param i          index of the subset
+     * @return the parent of the subset
+     */
+    static int find(final Component[] components, final int i) {
+        if (components[i].parent != i) {
+            components[i].parent = find(components, components[i].parent);
+        }
+        return components[i].parent;
+    }
+
+    /**
+     * Performs the Union operation for Union-Find
+     *
+     * @param components array of subsets
+     * @param x          index of the first subset
+     * @param y          index of the second subset
+     */
+    static void union(Component[] components, final int x, final int y) {
+        final int xroot = find(components, x);
+        final int yroot = find(components, y);
+
+        if (components[xroot].rank < components[yroot].rank) {
+            components[xroot].parent = yroot;
+        } else if (components[xroot].rank > components[yroot].rank) {
+            components[yroot].parent = xroot;
+        } else {
+            components[yroot].parent = xroot;
+            components[xroot].rank++;
+        }
+    }
+
+    /**
+     * Boruvka's algorithm to find the Minimum Spanning Tree
+     *
+     * @param graph the graph
+     * @return list of edges in the Minimum Spanning Tree
+     */
+    static List<Edge> boruvkaMST(final Graph graph) {
+        var boruvkaState = new BoruvkaState(graph);
+
+        while (boruvkaState.hasMoreEdgesToAdd()) {
+            final var cheapest = boruvkaState.computeCheapestEdges();
+            boruvkaState.merge(cheapest);
+        }
+        return boruvkaState.result;
+    }
+
+    /**
+     * Checks if the edge vertices are in a valid range
+     *
+     * @param vertex     the vertex to check
+     * @param upperBound the upper bound for the vertex range
+     */
+    private static void checkEdgeVertices(final int vertex, final int upperBound) {
+        if (vertex < 0 || vertex >= upperBound) {
+            throw new IllegalArgumentException("Edge vertex out of range");
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
new file mode 100644
index 000000000000..b5f75f5e831e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
@@ -0,0 +1,191 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.thealgorithms.datastructures.graphs.BoruvkaAlgorithm.Graph;
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class BoruvkaAlgorithmTest {
+    @Test
+    public void testBoruvkaMSTV9E14() {
+        List<BoruvkaAlgorithm.Edge> edges = new ArrayList<>();
+
+        edges.add(new BoruvkaAlgorithm.Edge(0, 1, 10));
+        edges.add(new BoruvkaAlgorithm.Edge(0, 2, 12));
+        edges.add(new BoruvkaAlgorithm.Edge(1, 2, 9));
+        edges.add(new BoruvkaAlgorithm.Edge(1, 3, 8));
+        edges.add(new BoruvkaAlgorithm.Edge(2, 4, 3));
+        edges.add(new BoruvkaAlgorithm.Edge(2, 5, 1));
+        edges.add(new BoruvkaAlgorithm.Edge(4, 5, 3));
+        edges.add(new BoruvkaAlgorithm.Edge(4, 3, 7));
+        edges.add(new BoruvkaAlgorithm.Edge(3, 6, 8));
+        edges.add(new BoruvkaAlgorithm.Edge(3, 7, 5));
+        edges.add(new BoruvkaAlgorithm.Edge(5, 7, 6));
+        edges.add(new BoruvkaAlgorithm.Edge(6, 7, 9));
+        edges.add(new BoruvkaAlgorithm.Edge(6, 8, 2));
+        edges.add(new BoruvkaAlgorithm.Edge(7, 8, 11));
+
+        final var graph = new Graph(9, edges);
+        /**
+         * Adjacency matrix
+         *    0   1   2   3   4   5   6   7   8
+         * 0  0  10  12   0   0   0   0   0   0
+         * 1 10   0   9   8   0   0   0   0   0
+         * 2 12   9   0   0   3   1   0   0   0
+         * 3  0   8   0   0   7   0   8   5   0
+         * 4  0   0   3   7   0   3   0   0   0
+         * 5  0   0   1   0   3   0   0   6   0
+         * 6  0   0   0   8   0   0   0   9   2
+         * 7  0   0   0   5   0   6   9   0  11
+         * 8  0   0   0   0   0   0   2  11   0
+         */
+        final var result = BoruvkaAlgorithm.boruvkaMST(graph);
+        assertEquals(8, result.size());
+        assertEquals(43, computeTotalWeight(result));
+    }
+
+    @Test
+    void testBoruvkaMSTV2E1() {
+        List<BoruvkaAlgorithm.Edge> edges = new ArrayList<>();
+
+        edges.add(new BoruvkaAlgorithm.Edge(0, 1, 10));
+
+        final var graph = new Graph(2, edges);
+
+        /**
+         * Adjacency matrix
+         *    0  1
+         * 0  0  10
+         * 1  10  0
+         */
+        final var result = BoruvkaAlgorithm.boruvkaMST(graph);
+        assertEquals(1, result.size());
+        assertEquals(10, computeTotalWeight(result));
+    }
+
+    @Test
+    void testCompleteGraphK4() {
+        List<BoruvkaAlgorithm.Edge> edges = new ArrayList<>();
+        edges.add(new BoruvkaAlgorithm.Edge(0, 1, 7));
+        edges.add(new BoruvkaAlgorithm.Edge(0, 2, 2));
+        edges.add(new BoruvkaAlgorithm.Edge(0, 3, 5));
+        edges.add(new BoruvkaAlgorithm.Edge(1, 2, 3));
+        edges.add(new BoruvkaAlgorithm.Edge(1, 3, 4));
+        edges.add(new BoruvkaAlgorithm.Edge(2, 3, 1));
+
+        final var graph = new Graph(4, edges);
+
+        /**
+         * Adjacency matrix
+         *    0  1  2  3
+         * 0  0  7  2  5
+         * 1  7  0  3  4
+         * 2  2  3  0  1
+         * 3  5  4  1  0
+         */
+        final var result = BoruvkaAlgorithm.boruvkaMST(graph);
+        assertEquals(3, result.size());
+        assertEquals(6, computeTotalWeight(result));
+    }
+
+    @Test
+    void testNegativeVertices() {
+        Exception exception1 = assertThrows(IllegalArgumentException.class, () -> new Graph(-1, null));
+        String expectedMessage = "Number of vertices must be positive";
+        String actualMessage = exception1.getMessage();
+
+        assertTrue(actualMessage.contains(expectedMessage));
+    }
+
+    @Test
+    void testEdgesNull() {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> new Graph(0, null));
+        String expectedMessage = "Edges list must not be null or empty";
+        String actualMessage = exception.getMessage();
+
+        assertTrue(actualMessage.contains(expectedMessage));
+    }
+
+    @Test
+    void testEdgesEmpty() {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> new Graph(0, new ArrayList<>()));
+        String expectedMessage = "Edges list must not be null or empty";
+        String actualMessage = exception.getMessage();
+
+        assertTrue(actualMessage.contains(expectedMessage));
+    }
+
+    @Test
+    void testEdgesRange() {
+        // Valid input
+        List<BoruvkaAlgorithm.Edge> validEdges = new ArrayList<>();
+        validEdges.add(new BoruvkaAlgorithm.Edge(0, 1, 2));
+        validEdges.add(new BoruvkaAlgorithm.Edge(1, 2, 3));
+        final var validGraph = new BoruvkaAlgorithm.Graph(3, validEdges);
+        assertEquals(validEdges, validGraph.edges);
+
+        // Edge source out of range
+        Exception exception1 = assertThrows(IllegalArgumentException.class, () -> {
+            List<BoruvkaAlgorithm.Edge> invalidEdges = new ArrayList<>();
+            invalidEdges.add(new BoruvkaAlgorithm.Edge(-1, 1, 2));
+            final var invalidGraph = new BoruvkaAlgorithm.Graph(1, invalidEdges);
+            assertEquals(invalidEdges, invalidGraph.edges);
+        });
+        String expectedMessage1 = "Edge vertex out of range";
+        String actualMessage1 = exception1.getMessage();
+
+        assertTrue(actualMessage1.contains(expectedMessage1));
+
+        // Edge source out of range
+        Exception exception2 = assertThrows(IllegalArgumentException.class, () -> {
+            List<BoruvkaAlgorithm.Edge> invalidEdges = new ArrayList<>();
+            invalidEdges.add(new BoruvkaAlgorithm.Edge(1, 0, 2));
+            final var invalidGraph = new BoruvkaAlgorithm.Graph(1, invalidEdges);
+            assertEquals(invalidEdges, invalidGraph.edges);
+        });
+        String expectedMessage2 = "Edge vertex out of range";
+        String actualMessage2 = exception2.getMessage();
+
+        assertTrue(actualMessage2.contains(expectedMessage2));
+
+        // Edge destination out of range
+        Exception exception3 = assertThrows(IllegalArgumentException.class, () -> {
+            List<BoruvkaAlgorithm.Edge> invalidEdges = new ArrayList<>();
+            invalidEdges.add(new BoruvkaAlgorithm.Edge(0, -1, 2));
+            final var invalidGraph = new BoruvkaAlgorithm.Graph(1, invalidEdges);
+            assertEquals(invalidEdges, invalidGraph.edges);
+        });
+        String expectedMessage3 = "Edge vertex out of range";
+        String actualMessage3 = exception3.getMessage();
+
+        assertTrue(actualMessage3.contains(expectedMessage3));
+
+        // Edge destination out of range
+        Exception exception4 = assertThrows(IllegalArgumentException.class, () -> {
+            List<BoruvkaAlgorithm.Edge> invalidEdges = new ArrayList<>();
+            invalidEdges.add(new BoruvkaAlgorithm.Edge(0, 1, 2));
+            final var invalidGraph = new BoruvkaAlgorithm.Graph(1, invalidEdges);
+            assertEquals(invalidEdges, invalidGraph.edges);
+        });
+        String expectedMessage4 = "Edge vertex out of range";
+        String actualMessage4 = exception4.getMessage();
+
+        assertTrue(actualMessage4.contains(expectedMessage4));
+    }
+
+    /**
+     * Computes the total weight of the Minimum Spanning Tree
+     *
+     * @param result list of edges in the Minimum Spanning Tree
+     * @return the total weight of the Minimum Spanning Tree
+     */
+    int computeTotalWeight(final List<BoruvkaAlgorithm.Edge> result) {
+        int totalWeight = 0;
+        for (final var edge : result) {
+            totalWeight += edge.weight;
+        }
+        return totalWeight;
+    }
+}

From 3001620c1eef3246f666c459f096ba390afce06b Mon Sep 17 00:00:00 2001
From: Niklas Hoefflin <122729995+itakurah@users.noreply.github.com>
Date: Mon, 4 Dec 2023 17:22:02 +0100
Subject: [PATCH 0069/1338] Add PN-Counter (#4974)

---
 DIRECTORY.md                                  |   2 +
 .../datastructures/crdt/PNCounter.java        | 100 ++++++++++++++++++
 .../datastructures/crdt/PNCounterTest.java    |  54 ++++++++++
 3 files changed, 156 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 89f08c27248b..0548d3455581 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -84,6 +84,7 @@
               * [MRUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java)
             * crdt
               * [GCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java)
+              * [PNCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java)
             * disjointsetunion
               * [DisjointSetUnion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java)
               * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/Node.java)
@@ -617,6 +618,7 @@
               * [MRUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java)
             * crdt
               * [GCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java)
+              * [PNCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java)
             * disjointsetunion
               * [DisjointSetUnionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java)
             * graphs
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java b/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java
new file mode 100644
index 000000000000..828e0b0804b3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java
@@ -0,0 +1,100 @@
+package com.thealgorithms.datastructures.crdt;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * PN-Counter (Positive-Negative Counter) is a state-based CRDT (Conflict-free Replicated Data Type)
+ * designed for tracking counts with both increments and decrements in a distributed and concurrent environment.
+ * It combines two G-Counters, one for increments (P) and one for decrements (N).
+ * The total count is obtained by subtracting the value of the decrement counter from the increment counter.
+ * This implementation supports incrementing, decrementing, querying the total count,
+ * comparing with other PN-Counters, and merging with another PN-Counter
+ * to compute the element-wise maximum for both increment and decrement counters.
+ * (https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type)
+ *
+ * @author itakurah (Niklas Hoefflin) (https://github.com/itakurah)
+ */
+
+class PNCounter {
+    private final Map<Integer, Integer> P;
+    private final Map<Integer, Integer> N;
+    private final int myId;
+    private final int n;
+
+    /**
+     * Constructs a PN-Counter for a cluster of n nodes.
+     *
+     * @param myId The identifier of the current node.
+     * @param n    The number of nodes in the cluster.
+     */
+    public PNCounter(int myId, int n) {
+        this.myId = myId;
+        this.n = n;
+        this.P = new HashMap<>();
+        this.N = new HashMap<>();
+
+        for (int i = 0; i < n; i++) {
+            P.put(i, 0);
+            N.put(i, 0);
+        }
+    }
+
+    /**
+     * Increments the increment counter for the current node.
+     */
+    public void increment() {
+        P.put(myId, P.get(myId) + 1);
+    }
+
+    /**
+     * Increments the decrement counter for the current node.
+     */
+    public void decrement() {
+        N.put(myId, N.get(myId) + 1);
+    }
+
+    /**
+     * Gets the total value of the counter by subtracting the decrement counter from the increment counter.
+     *
+     * @return The total value of the counter.
+     */
+    public int value() {
+        int sumP = P.values().stream().mapToInt(Integer::intValue).sum();
+        int sumN = N.values().stream().mapToInt(Integer::intValue).sum();
+        return sumP - sumN;
+    }
+
+    /**
+     * Compares the state of this PN-Counter with another PN-Counter.
+     *
+     * @param other The other PN-Counter to compare with.
+     * @return True if the state of this PN-Counter is less than or equal to the state of the other PN-Counter.
+     */
+    public boolean compare(PNCounter other) {
+        if (this.n != other.n) {
+            throw new IllegalArgumentException("Cannot compare PN-Counters with different number of nodes");
+        }
+        for (int i = 0; i < n; i++) {
+            if (this.P.get(i) > other.P.get(i) && this.N.get(i) > other.N.get(i)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Merges the state of this PN-Counter with another PN-Counter.
+     *
+     * @param other The other PN-Counter to merge with.
+     */
+    public void merge(PNCounter other) {
+        if (this.n != other.n) {
+            throw new IllegalArgumentException("Cannot merge PN-Counters with different number of nodes");
+        }
+        for (int i = 0; i < n; i++) {
+            this.P.put(i, Math.max(this.P.get(i), other.P.get(i)));
+            this.N.put(i, Math.max(this.N.get(i), other.N.get(i)));
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java
new file mode 100644
index 000000000000..46c22a6edcb7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.datastructures.crdt;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class PNCounterTest {
+
+    @Test
+    public void testIncrement() {
+        PNCounter counter = new PNCounter(0, 3);
+        counter.increment();
+        assertEquals(1, counter.value());
+    }
+
+    @Test
+    public void testDecrement() {
+        PNCounter counter = new PNCounter(0, 3);
+        counter.decrement();
+        assertEquals(-1, counter.value());
+    }
+
+    @Test
+    public void testIncrementAndDecrement() {
+        PNCounter counter = new PNCounter(0, 3);
+        counter.increment();
+        counter.increment();
+        counter.decrement();
+        assertEquals(1, counter.value());
+    }
+
+    @Test
+    public void testCompare() {
+        PNCounter counter1 = new PNCounter(0, 3);
+        counter1.increment();
+        PNCounter counter2 = new PNCounter(1, 3);
+        assertTrue(counter1.compare(counter2));
+        counter2.increment();
+        assertTrue(counter2.compare(counter1));
+        counter1.decrement();
+        assertFalse(counter1.compare(counter2));
+    }
+
+    @Test
+    public void testMerge() {
+        PNCounter counter1 = new PNCounter(0, 3);
+        counter1.increment();
+        counter1.increment();
+        PNCounter counter2 = new PNCounter(1, 3);
+        counter2.increment();
+        counter1.merge(counter2);
+        assertEquals(3, counter1.value());
+    }
+}

From e59a3b1ebba0b484fad64adb06aedc06eb366825 Mon Sep 17 00:00:00 2001
From: Niklas Hoefflin <122729995+itakurah@users.noreply.github.com>
Date: Tue, 5 Dec 2023 19:39:18 +0100
Subject: [PATCH 0070/1338] Add G-Set (Grow-only Set) (#4975)

---
 DIRECTORY.md                                  |  2 +
 .../datastructures/crdt/GSet.java             | 65 +++++++++++++++++
 .../datastructures/crdt/GSetTest.java         | 71 +++++++++++++++++++
 3 files changed, 138 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/crdt/GSet.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0548d3455581..4a94809560a1 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -84,6 +84,7 @@
               * [MRUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java)
             * crdt
               * [GCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java)
+              * [GSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java)
               * [PNCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java)
             * disjointsetunion
               * [DisjointSetUnion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java)
@@ -618,6 +619,7 @@
               * [MRUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java)
             * crdt
               * [GCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java)
+              * [GSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java)
               * [PNCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java)
             * disjointsetunion
               * [DisjointSetUnionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java b/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java
new file mode 100644
index 000000000000..37873adc2573
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java
@@ -0,0 +1,65 @@
+package com.thealgorithms.datastructures.crdt;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * GSet (Grow-only Set) is a state-based CRDT (Conflict-free Replicated Data Type)
+ * that allows only the addition of elements and ensures that once an element is added,
+ * it cannot be removed. The merge operation of two G-Sets is their union.
+ * This implementation supports adding elements, looking up elements, comparing with other G-Sets,
+ * and merging with another G-Set to create a new G-Set containing all unique elements from both sets.
+ * (https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type)
+ *
+ * @author itakurah (Niklas Hoefflin) (https://github.com/itakurah)
+ */
+
+public class GSet<T> {
+    private final Set<T> elements;
+
+    /**
+     * Constructs an empty G-Set.
+     */
+    public GSet() {
+        this.elements = new HashSet<>();
+    }
+
+    /**
+     * Adds an element to the G-Set.
+     *
+     * @param e the element to be added
+     */
+    public void addElement(T e) {
+        elements.add(e);
+    }
+
+    /**
+     * Checks if the given element is present in the G-Set.
+     *
+     * @param e the element to be checked
+     * @return true if the element is present, false otherwise
+     */
+    public boolean lookup(T e) {
+        return elements.contains(e);
+    }
+
+    /**
+     * Compares the G-Set with another G-Set to check if it is a subset.
+     *
+     * @param other the other G-Set to compare with
+     * @return true if the current G-Set is a subset of the other, false otherwise
+     */
+    public boolean compare(GSet<T> other) {
+        return elements.containsAll(other.elements);
+    }
+
+    /**
+     * Merges the current G-Set with another G-Set, creating a new G-Set
+     * containing all unique elements from both sets.
+     *
+     * @param other the G-Set to merge with
+     */
+    public void merge(GSet<T> other) {
+        elements.addAll(other.elements);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java
new file mode 100644
index 000000000000..99588259006f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java
@@ -0,0 +1,71 @@
+package com.thealgorithms.datastructures.crdt;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class GSetTest {
+
+    @Test
+    void testAddElement() {
+        GSet<String> gSet = new GSet<>();
+        gSet.addElement("apple");
+        gSet.addElement("orange");
+
+        assertTrue(gSet.lookup("apple"));
+        assertTrue(gSet.lookup("orange"));
+        assertFalse(gSet.lookup("banana"));
+    }
+
+    @Test
+    void testLookup() {
+        GSet<Integer> gSet = new GSet<>();
+        gSet.addElement(1);
+        gSet.addElement(2);
+
+        assertTrue(gSet.lookup(1));
+        assertTrue(gSet.lookup(2));
+        assertFalse(gSet.lookup(3));
+    }
+
+    @Test
+    void testCompare() {
+        GSet<String> gSet1 = new GSet<>();
+        GSet<String> gSet2 = new GSet<>();
+
+        gSet1.addElement("apple");
+        gSet1.addElement("orange");
+
+        gSet2.addElement("orange");
+        gSet2.addElement("banana");
+
+        assertFalse(gSet1.compare(gSet2));
+
+        GSet<String> gSet3 = new GSet<>();
+        gSet3.addElement("apple");
+        gSet3.addElement("orange");
+
+        assertTrue(gSet1.compare(gSet3));
+    }
+
+    @Test
+    void testMerge() {
+        GSet<String> gSet1 = new GSet<>();
+        GSet<String> gSet2 = new GSet<>();
+
+        gSet1.addElement("apple");
+        gSet1.addElement("orange");
+
+        gSet2.addElement("orange");
+        gSet2.addElement("banana");
+
+        GSet<String> mergedSet = new GSet<>();
+        mergedSet.merge(gSet1);
+        mergedSet.merge(gSet2);
+
+        assertTrue(mergedSet.lookup("apple"));
+        assertTrue(mergedSet.lookup("orange"));
+        assertTrue(mergedSet.lookup("banana"));
+        assertFalse(mergedSet.lookup("grape"));
+    }
+}

From 36580bac1e1901486950a2df27e534665f47e6b7 Mon Sep 17 00:00:00 2001
From: Nassor Shabataka <86209375+ImmaculateShaba@users.noreply.github.com>
Date: Wed, 6 Dec 2023 02:37:58 -0500
Subject: [PATCH 0071/1338] Fix typo in NextGraterElement (#4976)

---
 ...erElement.java => NextGreaterElement.java} | 24 +++++++++----------
 1 file changed, 12 insertions(+), 12 deletions(-)
 rename src/main/java/com/thealgorithms/stacks/{NextGraterElement.java => NextGreaterElement.java} (69%)

diff --git a/src/main/java/com/thealgorithms/stacks/NextGraterElement.java b/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java
similarity index 69%
rename from src/main/java/com/thealgorithms/stacks/NextGraterElement.java
rename to src/main/java/com/thealgorithms/stacks/NextGreaterElement.java
index 0cf56349c662..d681e41fbfc3 100644
--- a/src/main/java/com/thealgorithms/stacks/NextGraterElement.java
+++ b/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java
@@ -4,26 +4,26 @@
 import java.util.Stack;
 
 /*
-    Given an array "input" you need to print the first grater element for each element.
-    For a given element x of an array, the Next Grater element of that element is the
-    first grater element to the right side of it. If no such element is present print -1.
+    Given an array "input" you need to print the first greater element for each element.
+    For a given element x of an array, the Next greater element of that element is the
+    first greater element to the right side of it. If no such element is present print -1.
 
     Example
     input = { 2, 7, 3, 5, 4, 6, 8 };
     At i = 0
-    Next Grater element between (1 to n) is 7
+    Next greater element between (1 to n) is 7
     At i = 1
-    Next Grater element between (2 to n) is 8
+    Next greater element between (2 to n) is 8
     At i = 2
-    Next Grater element between (3 to n) is 5
+    Next greater element between (3 to n) is 5
     At i = 3
-    Next Grater element between (4 to n) is 6
+    Next greater element between (4 to n) is 6
     At i = 4
-    Next Grater element between (5 to n) is 6
+    Next greater element between (5 to n) is 6
     At i = 5
-    Next Grater element between (6 to n) is 8
+    Next greater element between (6 to n) is 8
     At i = 6
-    Next Grater element between (6 to n) is -1
+    Next greater element between (6 to n) is -1
 
     result : [7, 8, 5, 6, 6, 8, -1]
 
@@ -37,11 +37,11 @@ Next Grater element between (6 to n) is -1
             popped elements.
         d. Finally, push the next in the stack.
 
-    3. If elements are left in stack after completing while loop then their Next Grater element is
+    3. If elements are left in stack after completing while loop then their Next greater element is
    -1.
  */
 
-public class NextGraterElement {
+public class NextGreaterElement {
 
     public static int[] findNextGreaterElements(int[] array) {
         if (array == null) {

From 249ee1dc994735a6cf02a6048ab8bedd2e91ce4a Mon Sep 17 00:00:00 2001
From: Niklas Hoefflin <122729995+itakurah@users.noreply.github.com>
Date: Thu, 7 Dec 2023 16:23:22 +0100
Subject: [PATCH 0072/1338] Add 2P-Set (Two-Phase Set) for both addition and
 removal operations in distributed systems (#4977)

---
 DIRECTORY.md                                  |  4 +-
 .../datastructures/crdt/TwoPSet.java          | 84 +++++++++++++++++++
 .../datastructures/crdt/TwoPSetTest.java      | 68 +++++++++++++++
 3 files changed, 155 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 4a94809560a1..703642a0d28e 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -86,6 +86,7 @@
               * [GCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java)
               * [GSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java)
               * [PNCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java)
+              * [TwoPSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java)
             * disjointsetunion
               * [DisjointSetUnion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java)
               * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/Node.java)
@@ -528,7 +529,7 @@
             * [InfixToPostfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java)
             * [LargestRectangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/LargestRectangle.java)
             * [MaximumMinimumWindow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java)
-            * [NextGraterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextGraterElement.java)
+            * [NextGreaterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java)
             * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
             * [PostfixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java)
             * [StackPostfixNotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
@@ -621,6 +622,7 @@
               * [GCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java)
               * [GSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java)
               * [PNCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java)
+              * [TwoPSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java)
             * disjointsetunion
               * [DisjointSetUnionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java)
             * graphs
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java b/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java
new file mode 100644
index 000000000000..f5e155c28d8d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java
@@ -0,0 +1,84 @@
+package com.thealgorithms.datastructures.crdt;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * TwoPhaseSet (2P-Set) is a state-based CRDT (Conflict-free Replicated Data Type) designed for managing sets
+ * with support for both addition and removal operations in a distributed and concurrent environment.
+ * It combines two G-Sets (grow-only sets) - one set for additions and another set (tombstone set) for removals.
+ * Once an element is removed and placed in the tombstone set, it cannot be re-added, adhering to "remove-wins" semantics.
+ * This implementation supports querying the presence of elements, adding elements, removing elements,
+ * comparing with other 2P-Sets, and merging two 2P-Sets while preserving the remove-wins semantics.
+ * (https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type)
+ *
+ * @author itakurah (Niklas Hoefflin) (https://github.com/itakurah)
+ */
+
+public class TwoPSet {
+    private Set<String> setA;
+    private Set<String> setR;
+
+    /**
+     * Constructs an empty Two-Phase Set.
+     */
+    public TwoPSet() {
+        this.setA = new HashSet<>();
+        this.setR = new HashSet<>();
+    }
+
+    /**
+     * Checks if an element is in the set and has not been removed.
+     *
+     * @param element The element to be checked.
+     * @return True if the element is in the set and has not been removed, otherwise false.
+     */
+    public boolean lookup(String element) {
+        return setA.contains(element) && !setR.contains(element);
+    }
+
+    /**
+     * Adds an element to the set.
+     *
+     * @param element The element to be added.
+     */
+    public void add(String element) {
+        setA.add(element);
+    }
+
+    /**
+     * Removes an element from the set. The element will be placed in the tombstone set.
+     *
+     * @param element The element to be removed.
+     */
+    public void remove(String element) {
+        if (lookup(element)) {
+            setR.add(element);
+        }
+    }
+
+    /**
+     * Compares the current 2P-Set with another 2P-Set.
+     *
+     * @param otherSet The other 2P-Set to compare with.
+     * @return True if both SetA and SetR are subset, otherwise false.
+     */
+    public boolean compare(TwoPSet otherSet) {
+        return otherSet.setA.containsAll(setA) && otherSet.setR.containsAll(setR);
+    }
+
+    /**
+     * Merges the current 2P-Set with another 2P-Set.
+     *
+     * @param otherSet The other 2P-Set to merge with.
+     * @return A new 2P-Set containing the merged elements.
+     */
+    public TwoPSet merge(TwoPSet otherSet) {
+        TwoPSet mergedSet = new TwoPSet();
+        mergedSet.setA.addAll(this.setA);
+        mergedSet.setA.addAll(otherSet.setA);
+        mergedSet.setR.addAll(this.setR);
+        mergedSet.setR.addAll(otherSet.setR);
+        return mergedSet;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java
new file mode 100644
index 000000000000..18ab5c169e5c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java
@@ -0,0 +1,68 @@
+package com.thealgorithms.datastructures.crdt;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class TwoPSetTest {
+
+    private TwoPSet set;
+
+    @BeforeEach
+    void setUp() {
+        set = new TwoPSet();
+    }
+
+    @Test
+    void testLookup() {
+        set.add("A");
+        assertTrue(set.lookup("A"));
+        assertFalse(set.lookup("B"));
+        set.remove("A");
+        assertFalse(set.lookup("A"));
+    }
+
+    @Test
+    void testAdd() {
+        set.add("A");
+        assertTrue(set.lookup("A"));
+    }
+
+    @Test
+    void testRemove() {
+        set.add("A");
+        set.remove("A");
+        assertFalse(set.lookup("A"));
+    }
+
+    @Test
+    void testCompare() {
+        TwoPSet set1 = new TwoPSet();
+        set1.add("A");
+        set1.add("B");
+        TwoPSet set2 = new TwoPSet();
+        set2.add("A");
+        assertFalse(set1.compare(set2));
+        set2.add("B");
+        assertTrue(set1.compare(set2));
+        set1.remove("A");
+        assertFalse(set1.compare(set2));
+        set2.remove("A");
+        assertTrue(set1.compare(set2));
+    }
+
+    @Test
+    void testMerge() {
+        TwoPSet set1 = new TwoPSet();
+        set1.add("A");
+        set1.add("B");
+        TwoPSet set2 = new TwoPSet();
+        set2.add("B");
+        set2.add("C");
+        TwoPSet mergedSet = set1.merge(set2);
+        assertTrue(mergedSet.lookup("A"));
+        assertTrue(mergedSet.lookup("B"));
+        assertTrue(mergedSet.lookup("C"));
+    }
+}

From 92131de3774d6dc7be7662bd0a8a9c02704255d5 Mon Sep 17 00:00:00 2001
From: Niklas Hoefflin <122729995+itakurah@users.noreply.github.com>
Date: Thu, 7 Dec 2023 17:06:56 +0100
Subject: [PATCH 0073/1338] =?UTF-8?q?Fix=20compare()=20for=20subset=20chec?=
 =?UTF-8?q?k=20(S.A=20=E2=8A=86=20T.A)=20(#4978)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../thealgorithms/datastructures/crdt/GSet.java    |  2 +-
 .../datastructures/crdt/GSetTest.java              | 14 ++++----------
 2 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java b/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java
index 37873adc2573..2b8959ed0136 100644
--- a/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java
@@ -50,7 +50,7 @@ public boolean lookup(T e) {
      * @return true if the current G-Set is a subset of the other, false otherwise
      */
     public boolean compare(GSet<T> other) {
-        return elements.containsAll(other.elements);
+        return other.elements.containsAll(elements);
     }
 
     /**
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java
index 99588259006f..74250ede1f23 100644
--- a/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java
@@ -32,20 +32,14 @@ void testLookup() {
     void testCompare() {
         GSet<String> gSet1 = new GSet<>();
         GSet<String> gSet2 = new GSet<>();
-
         gSet1.addElement("apple");
         gSet1.addElement("orange");
-
         gSet2.addElement("orange");
-        gSet2.addElement("banana");
-
         assertFalse(gSet1.compare(gSet2));
-
-        GSet<String> gSet3 = new GSet<>();
-        gSet3.addElement("apple");
-        gSet3.addElement("orange");
-
-        assertTrue(gSet1.compare(gSet3));
+        gSet2.addElement("apple");
+        assertTrue(gSet1.compare(gSet2));
+        gSet2.addElement("banana");
+        assertTrue(gSet1.compare(gSet2));
     }
 
     @Test

From b8b1dea38de84d7647921cd1859b7d58303e9b86 Mon Sep 17 00:00:00 2001
From: Niklas Hoefflin <122729995+itakurah@users.noreply.github.com>
Date: Fri, 8 Dec 2023 19:57:07 +0100
Subject: [PATCH 0074/1338] Add LWW Element Set (Last Write Wins Element Set)
 (#4979)

---
 DIRECTORY.md                                  |   2 +
 .../datastructures/crdt/LWWElementSet.java    | 138 ++++++++++++++++++
 .../crdt/LWWElementSetTest.java               | 107 ++++++++++++++
 3 files changed, 247 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 703642a0d28e..f033416dc38a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -85,6 +85,7 @@
             * crdt
               * [GCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java)
               * [GSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java)
+              * [LWWElementSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java)
               * [PNCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java)
               * [TwoPSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java)
             * disjointsetunion
@@ -621,6 +622,7 @@
             * crdt
               * [GCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java)
               * [GSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java)
+              * [LWWElementSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java)
               * [PNCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java)
               * [TwoPSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java)
             * disjointsetunion
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java b/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
new file mode 100644
index 000000000000..722c916ab0ce
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
@@ -0,0 +1,138 @@
+package com.thealgorithms.datastructures.crdt;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Last-Write-Wins Element Set (LWWElementSet) is a state-based CRDT (Conflict-free Replicated Data Type)
+ * designed for managing sets in a distributed and concurrent environment. It supports the addition and removal
+ * of elements, using timestamps to determine the order of operations. The set is split into two subsets:
+ * the add set for elements to be added and the remove set for elements to be removed.
+ *
+ * @author itakurah (Niklas Hoefflin) (https://github.com/itakurah)
+ * @see <a href="https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type">Conflict-free_replicated_data_type</a>
+ * @see <a href="https://github.com/itakurah">itakurah (Niklas Hoefflin)</a>
+ */
+
+class Element {
+    String key;
+    int timestamp;
+    Bias bias;
+
+    /**
+     * Constructs a new Element with the specified key, timestamp and bias.
+     *
+     * @param key       The key of the element.
+     * @param timestamp The timestamp associated with the element.
+     * @param bias      The bias of the element (ADDS or REMOVALS).
+     */
+    public Element(String key, int timestamp, Bias bias) {
+        this.key = key;
+        this.timestamp = timestamp;
+        this.bias = bias;
+    }
+}
+
+enum Bias {
+    /**
+     * ADDS bias for the add set.
+     * REMOVALS bias for the remove set.
+     */
+    ADDS,
+    REMOVALS
+}
+
+class LWWElementSet {
+    private final Map<String, Element> addSet;
+    private final Map<String, Element> removeSet;
+
+    /**
+     * Constructs an empty LWWElementSet.
+     */
+    public LWWElementSet() {
+        this.addSet = new HashMap<>();
+        this.removeSet = new HashMap<>();
+    }
+
+    /**
+     * Adds an element to the addSet.
+     *
+     * @param e The element to be added.
+     */
+    public void add(Element e) {
+        addSet.put(e.key, e);
+    }
+
+    /**
+     * Removes an element from the removeSet.
+     *
+     * @param e The element to be removed.
+     */
+    public void remove(Element e) {
+        if (lookup(e)) {
+            removeSet.put(e.key, e);
+        }
+    }
+
+    /**
+     * Checks if an element is in the LWWElementSet by comparing timestamps in the addSet and removeSet.
+     *
+     * @param e The element to be checked.
+     * @return True if the element is present, false otherwise.
+     */
+    public boolean lookup(Element e) {
+        Element inAddSet = addSet.get(e.key);
+        Element inRemoveSet = removeSet.get(e.key);
+
+        return (inAddSet != null && (inRemoveSet == null || inAddSet.timestamp > inRemoveSet.timestamp));
+    }
+
+    /**
+     * Compares the LWWElementSet with another LWWElementSet to check if addSet and removeSet are a subset.
+     *
+     * @param other The LWWElementSet to compare.
+     * @return True if the set is subset, false otherwise.
+     */
+    public boolean compare(LWWElementSet other) {
+        return other.addSet.keySet().containsAll(addSet.keySet()) && other.removeSet.keySet().containsAll(removeSet.keySet());
+    }
+
+    /**
+     * Merges another LWWElementSet into this set by resolving conflicts based on timestamps.
+     *
+     * @param other The LWWElementSet to merge.
+     */
+    public void merge(LWWElementSet other) {
+        for (Element e : other.addSet.values()) {
+            if (!addSet.containsKey(e.key) || compareTimestamps(addSet.get(e.key), e)) {
+                addSet.put(e.key, e);
+            }
+        }
+
+        for (Element e : other.removeSet.values()) {
+            if (!removeSet.containsKey(e.key) || compareTimestamps(removeSet.get(e.key), e)) {
+                removeSet.put(e.key, e);
+            }
+        }
+    }
+
+    /**
+     * Compares timestamps of two elements based on their bias (ADDS or REMOVALS).
+     *
+     * @param e     The first element.
+     * @param other The second element.
+     * @return True if the first element's timestamp is greater or the bias is ADDS and timestamps are equal.
+     */
+    public boolean compareTimestamps(Element e, Element other) {
+        if (!e.bias.equals(other.bias)) {
+            throw new IllegalArgumentException("Invalid bias value");
+        }
+        Bias bias = e.bias;
+        int timestampComparison = Integer.compare(e.timestamp, other.timestamp);
+
+        if (timestampComparison == 0) {
+            return !bias.equals(Bias.ADDS);
+        }
+        return timestampComparison < 0;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java
new file mode 100644
index 000000000000..6fb227bd80c5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java
@@ -0,0 +1,107 @@
+package com.thealgorithms.datastructures.crdt;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class LWWElementSetTest {
+
+    private LWWElementSet set;
+    private final Bias bias = Bias.ADDS;
+
+    @BeforeEach
+    void setUp() {
+        set = new LWWElementSet();
+    }
+
+    @Test
+    void testAdd() {
+        Element element = new Element("key1", 1, bias);
+        set.add(element);
+
+        assertTrue(set.lookup(element));
+    }
+
+    @Test
+    void testRemove() {
+        Element element = new Element("key1", 1, bias);
+        set.add(element);
+        set.remove(element);
+
+        assertFalse(set.lookup(element));
+    }
+
+    @Test
+    void testRemoveNonexistentElement() {
+        Element element = new Element("key1", 1, bias);
+        set.remove(element);
+
+        assertFalse(set.lookup(element));
+    }
+
+    @Test
+    void testLookupNonexistentElement() {
+        Element element = new Element("key1", 1, bias);
+
+        assertFalse(set.lookup(element));
+    }
+
+    @Test
+    void testCompareEqualSets() {
+        LWWElementSet otherSet = new LWWElementSet();
+
+        Element element = new Element("key1", 1, bias);
+        set.add(element);
+        otherSet.add(element);
+
+        assertTrue(set.compare(otherSet));
+
+        otherSet.add(new Element("key2", 2, bias));
+        assertTrue(set.compare(otherSet));
+    }
+
+    @Test
+    void testCompareDifferentSets() {
+        LWWElementSet otherSet = new LWWElementSet();
+
+        Element element1 = new Element("key1", 1, bias);
+        Element element2 = new Element("key2", 2, bias);
+
+        set.add(element1);
+        otherSet.add(element2);
+
+        assertFalse(set.compare(otherSet));
+    }
+
+    @Test
+    void testMerge() {
+        LWWElementSet otherSet = new LWWElementSet();
+
+        Element element1 = new Element("key1", 1, bias);
+        Element element2 = new Element("key2", 2, bias);
+
+        set.add(element1);
+        otherSet.add(element2);
+
+        set.merge(otherSet);
+
+        assertTrue(set.lookup(element1));
+        assertTrue(set.lookup(element2));
+    }
+
+    @Test
+    void testCompareTimestampsEqualTimestamps() {
+        LWWElementSet lwwElementSet = new LWWElementSet();
+
+        Element e1 = new Element("key1", 10, Bias.REMOVALS);
+        Element e2 = new Element("key1", 10, Bias.REMOVALS);
+
+        assertTrue(lwwElementSet.compareTimestamps(e1, e2));
+
+        e1 = new Element("key1", 10, Bias.ADDS);
+        e2 = new Element("key1", 10, Bias.ADDS);
+
+        assertFalse(lwwElementSet.compareTimestamps(e1, e2));
+    }
+}

From 4aa8e6a0eb65e8edb9b716851ee4dd8881c434af Mon Sep 17 00:00:00 2001
From: Niklas Hoefflin <122729995+itakurah@users.noreply.github.com>
Date: Mon, 11 Dec 2023 19:58:56 +0100
Subject: [PATCH 0075/1338] Updated TwoPSet to use Generics instead of Strings
 (#4981)

---
 .../datastructures/crdt/TwoPSet.java           | 18 +++++++++---------
 .../datastructures/crdt/TwoPSetTest.java       | 14 +++++++-------
 2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java b/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java
index f5e155c28d8d..c0ce17b2802b 100644
--- a/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java
@@ -15,9 +15,9 @@
  * @author itakurah (Niklas Hoefflin) (https://github.com/itakurah)
  */
 
-public class TwoPSet {
-    private Set<String> setA;
-    private Set<String> setR;
+public class TwoPSet<T> {
+    private final Set<T> setA;
+    private final Set<T> setR;
 
     /**
      * Constructs an empty Two-Phase Set.
@@ -33,7 +33,7 @@ public TwoPSet() {
      * @param element The element to be checked.
      * @return True if the element is in the set and has not been removed, otherwise false.
      */
-    public boolean lookup(String element) {
+    public boolean lookup(T element) {
         return setA.contains(element) && !setR.contains(element);
     }
 
@@ -42,7 +42,7 @@ public boolean lookup(String element) {
      *
      * @param element The element to be added.
      */
-    public void add(String element) {
+    public void add(T element) {
         setA.add(element);
     }
 
@@ -51,7 +51,7 @@ public void add(String element) {
      *
      * @param element The element to be removed.
      */
-    public void remove(String element) {
+    public void remove(T element) {
         if (lookup(element)) {
             setR.add(element);
         }
@@ -63,7 +63,7 @@ public void remove(String element) {
      * @param otherSet The other 2P-Set to compare with.
      * @return True if both SetA and SetR are subset, otherwise false.
      */
-    public boolean compare(TwoPSet otherSet) {
+    public boolean compare(TwoPSet<T> otherSet) {
         return otherSet.setA.containsAll(setA) && otherSet.setR.containsAll(setR);
     }
 
@@ -73,8 +73,8 @@ public boolean compare(TwoPSet otherSet) {
      * @param otherSet The other 2P-Set to merge with.
      * @return A new 2P-Set containing the merged elements.
      */
-    public TwoPSet merge(TwoPSet otherSet) {
-        TwoPSet mergedSet = new TwoPSet();
+    public TwoPSet<T> merge(TwoPSet<T> otherSet) {
+        TwoPSet<T> mergedSet = new TwoPSet<>();
         mergedSet.setA.addAll(this.setA);
         mergedSet.setA.addAll(otherSet.setA);
         mergedSet.setR.addAll(this.setR);
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java
index 18ab5c169e5c..d81362e854d0 100644
--- a/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java
@@ -7,11 +7,11 @@
 
 class TwoPSetTest {
 
-    private TwoPSet set;
+    private TwoPSet<String> set;
 
     @BeforeEach
     void setUp() {
-        set = new TwoPSet();
+        set = new TwoPSet<>();
     }
 
     @Test
@@ -38,10 +38,10 @@ void testRemove() {
 
     @Test
     void testCompare() {
-        TwoPSet set1 = new TwoPSet();
+        TwoPSet<String> set1 = new TwoPSet<>();
         set1.add("A");
         set1.add("B");
-        TwoPSet set2 = new TwoPSet();
+        TwoPSet<String> set2 = new TwoPSet<>();
         set2.add("A");
         assertFalse(set1.compare(set2));
         set2.add("B");
@@ -54,13 +54,13 @@ void testCompare() {
 
     @Test
     void testMerge() {
-        TwoPSet set1 = new TwoPSet();
+        TwoPSet<String> set1 = new TwoPSet<>();
         set1.add("A");
         set1.add("B");
-        TwoPSet set2 = new TwoPSet();
+        TwoPSet<String> set2 = new TwoPSet<>();
         set2.add("B");
         set2.add("C");
-        TwoPSet mergedSet = set1.merge(set2);
+        TwoPSet<String> mergedSet = set1.merge(set2);
         assertTrue(mergedSet.lookup("A"));
         assertTrue(mergedSet.lookup("B"));
         assertTrue(mergedSet.lookup("C"));

From e26fd9da71130837d327d747f6bc87688322eee5 Mon Sep 17 00:00:00 2001
From: Niklas Hoefflin <122729995+itakurah@users.noreply.github.com>
Date: Mon, 11 Dec 2023 22:05:43 +0100
Subject: [PATCH 0076/1338] Add OR-Set (Observed-Remove Set) (#4980)

---
 DIRECTORY.md                                  |   2 +
 .../datastructures/crdt/ORSet.java            | 191 ++++++++++++++++++
 .../datastructures/crdt/ORSetTest.java        |  86 ++++++++
 3 files changed, 279 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/crdt/ORSet.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index f033416dc38a..b769250e4749 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -86,6 +86,7 @@
               * [GCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java)
               * [GSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java)
               * [LWWElementSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java)
+              * [ORSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/ORSet.java)
               * [PNCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java)
               * [TwoPSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java)
             * disjointsetunion
@@ -623,6 +624,7 @@
               * [GCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java)
               * [GSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java)
               * [LWWElementSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java)
+              * [ORSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java)
               * [PNCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java)
               * [TwoPSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java)
             * disjointsetunion
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/ORSet.java b/src/main/java/com/thealgorithms/datastructures/crdt/ORSet.java
new file mode 100644
index 000000000000..a4cc2ffdd4a6
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/ORSet.java
@@ -0,0 +1,191 @@
+package com.thealgorithms.datastructures.crdt;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.UUID;
+
+/**
+ * ORSet (Observed-Removed Set) is a state-based CRDT (Conflict-free Replicated Data Type)
+ * that supports both addition and removal of elements. This particular implementation follows
+ * the Add-Wins strategy, meaning that in case of conflicting add and remove operations,
+ * the add operation takes precedence. The merge operation of two OR-Sets ensures that
+ * elements added at any replica are eventually observed at all replicas. Removed elements,
+ * once observed, are never reintroduced.
+ * This OR-Set implementation provides methods for adding elements, removing elements,
+ * checking for element existence, retrieving the set of elements, comparing with other OR-Sets,
+ * and merging with another OR-Set to create a new OR-Set containing all unique elements
+ * from both sets.
+ *
+ * @author itakurah (Niklas Hoefflin) (https://github.com/itakurah)
+ * @see <a href="https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type">Conflict-free_replicated_data_type</a>
+ * @see <a href="https://github.com/itakurah">itakurah (Niklas Hoefflin)</a>
+ */
+
+public class ORSet<T> {
+
+    private final Set<Pair<T>> elements;
+    private final Set<Pair<T>> tombstones;
+
+    /**
+     * Constructs an empty OR-Set.
+     */
+    public ORSet() {
+        this.elements = new HashSet<>();
+        this.tombstones = new HashSet<>();
+    }
+
+    /**
+     * Checks if the set contains the specified element.
+     *
+     * @param element the element to check for
+     * @return true if the set contains the element, false otherwise
+     */
+    public boolean contains(T element) {
+        return elements.stream().anyMatch(pair -> pair.getElement().equals(element));
+    }
+
+    /**
+     * Retrieves the elements in the set.
+     *
+     * @return a set containing the elements
+     */
+    public Set<T> elements() {
+        Set<T> result = new HashSet<>();
+        elements.forEach(pair -> result.add(pair.getElement()));
+        return result;
+    }
+
+    /**
+     * Adds the specified element to the set.
+     *
+     * @param element the element to add
+     */
+    public void add(T element) {
+        String n = prepare();
+        effect(element, n);
+    }
+
+    /**
+     * Removes the specified element from the set.
+     *
+     * @param element the element to remove
+     */
+    public void remove(T element) {
+        Set<Pair<T>> pairsToRemove = prepare(element);
+        effect(pairsToRemove);
+    }
+
+    /**
+     * Collect all pairs with the specified element.
+     *
+     * @param element the element to collect pairs for
+     * @return a set of pairs with the specified element to be removed
+     */
+    private Set<Pair<T>> prepare(T element) {
+        Set<Pair<T>> pairsToRemove = new HashSet<>();
+        for (Pair<T> pair : elements) {
+            if (pair.getElement().equals(element)) {
+                pairsToRemove.add(pair);
+            }
+        }
+        return pairsToRemove;
+    }
+
+    /**
+     * Generates a unique tag for the element.
+     *
+     * @return the unique tag
+     */
+    private String prepare() {
+        return generateUniqueTag();
+    }
+
+    /**
+     * Adds the element with the specified unique tag to the set.
+     *
+     * @param element the element to add
+     * @param n       the unique tag associated with the element
+     */
+    private void effect(T element, String n) {
+        Pair<T> pair = new Pair<>(element, n);
+        elements.add(pair);
+        elements.removeAll(tombstones);
+    }
+
+    /**
+     * Removes the specified pairs from the set.
+     *
+     * @param pairsToRemove the pairs to remove
+     */
+    private void effect(Set<Pair<T>> pairsToRemove) {
+        elements.removeAll(pairsToRemove);
+        tombstones.addAll(pairsToRemove);
+    }
+
+    /**
+     * Generates a unique tag.
+     *
+     * @return the unique tag
+     */
+    private String generateUniqueTag() {
+        return UUID.randomUUID().toString();
+    }
+
+    /**
+     * Compares this Add-Wins OR-Set with another OR-Set to check if elements and tombstones are a subset.
+     *
+     * @param other the other OR-Set to compare
+     * @return true if the sets are subset, false otherwise
+     */
+    public boolean compare(ORSet<T> other) {
+        Set<Pair<T>> union = new HashSet<>(elements);
+        union.addAll(tombstones);
+
+        Set<Pair<T>> otherUnion = new HashSet<>(other.elements);
+        otherUnion.addAll(other.tombstones);
+
+        return otherUnion.containsAll(union) && other.tombstones.containsAll(tombstones);
+    }
+
+    /**
+     * Merges this Add-Wins OR-Set with another OR-Set.
+     *
+     * @param other the other OR-Set to merge
+     */
+    public void merge(ORSet<T> other) {
+        elements.removeAll(other.tombstones);
+        other.elements.removeAll(tombstones);
+        elements.addAll(other.elements);
+        tombstones.addAll(other.tombstones);
+    }
+
+    /**
+     * Represents a pair containing an element and a unique tag.
+     *
+     * @param <T> the type of the element in the pair
+     */
+    public static class Pair<T> {
+        private final T element;
+        private final String uniqueTag;
+
+        /**
+         * Constructs a pair with the specified element and unique tag.
+         *
+         * @param element   the element in the pair
+         * @param uniqueTag the unique tag associated with the element
+         */
+        public Pair(T element, String uniqueTag) {
+            this.element = element;
+            this.uniqueTag = uniqueTag;
+        }
+
+        /**
+         * Gets the element from the pair.
+         *
+         * @return the element
+         */
+        public T getElement() {
+            return element;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java
new file mode 100644
index 000000000000..f12c38f174dc
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java
@@ -0,0 +1,86 @@
+package com.thealgorithms.datastructures.crdt;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.Set;
+import org.junit.jupiter.api.Test;
+
+class ORSetTest {
+
+    @Test
+    void testContains() {
+        ORSet<String> orSet = new ORSet<>();
+        orSet.add("A");
+        assertTrue(orSet.contains("A"));
+    }
+
+    @Test
+    void testAdd() {
+        ORSet<String> orSet = new ORSet<>();
+        orSet.add("A");
+        assertTrue(orSet.contains("A"));
+    }
+
+    @Test
+    void testRemove() {
+        ORSet<String> orSet = new ORSet<>();
+        orSet.add("A");
+        orSet.add("A");
+        orSet.remove("A");
+        assertFalse(orSet.contains("A"));
+    }
+
+    @Test
+    void testElements() {
+        ORSet<String> orSet = new ORSet<>();
+        orSet.add("A");
+        orSet.add("B");
+        assertEquals(Set.of("A", "B"), orSet.elements());
+    }
+
+    @Test
+    void testCompareEqualSets() {
+        ORSet<String> orSet1 = new ORSet<>();
+        ORSet<String> orSet2 = new ORSet<>();
+
+        orSet1.add("A");
+        orSet2.add("A");
+        orSet2.add("B");
+        orSet2.add("C");
+        orSet2.remove("C");
+        orSet1.merge(orSet2);
+        orSet2.merge(orSet1);
+        orSet2.remove("B");
+
+        assertTrue(orSet1.compare(orSet2));
+    }
+
+    @Test
+    void testCompareDifferentSets() {
+        ORSet<String> orSet1 = new ORSet<>();
+        ORSet<String> orSet2 = new ORSet<>();
+
+        orSet1.add("A");
+        orSet2.add("B");
+
+        assertFalse(orSet1.compare(orSet2));
+    }
+
+    @Test
+    void testMerge() {
+        ORSet<String> orSet1 = new ORSet<>();
+        ORSet<String> orSet2 = new ORSet<>();
+
+        orSet1.add("A");
+        orSet1.add("A");
+        orSet1.add("B");
+        orSet1.remove("B");
+        orSet2.add("B");
+        orSet2.add("C");
+        orSet2.remove("C");
+        orSet1.merge(orSet2);
+
+        assertTrue(orSet1.contains("A"));
+        assertTrue(orSet1.contains("B"));
+    }
+}

From 7ece806cf5cae7c3531f2eb54c56cf33fed2e579 Mon Sep 17 00:00:00 2001
From: aryan1165 <111041731+aryan1165@users.noreply.github.com>
Date: Tue, 26 Dec 2023 03:54:28 +0530
Subject: [PATCH 0077/1338] Remove duplicate file of Simple Substitution Cipher
 (fixes #4494) (#4495)

---
 DIRECTORY.md                                  |  2 -
 .../ciphers/SimpleSubstitutionCipher.java     | 83 -------------------
 .../ciphers/SimpleSubstitutionCipherTest.java | 48 -----------
 3 files changed, 133 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/ciphers/SimpleSubstitutionCipher.java
 delete mode 100644 src/test/java/com/thealgorithms/ciphers/SimpleSubstitutionCipherTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b769250e4749..fd50b2914cff 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -48,7 +48,6 @@
             * [ProductCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ProductCipher.java)
             * [RSA](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/RSA.java)
             * [SimpleSubCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/SimpleSubCipher.java)
-            * [SimpleSubstitutionCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/SimpleSubstitutionCipher.java)
             * [Vigenere](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Vigenere.java)
           * conversions
             * [AnyBaseToAnyBase](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java)
@@ -596,7 +595,6 @@
             * [PolybiusTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
             * [RSATest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RSATest.java)
             * [SimpleSubCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/SimpleSubCipherTest.java)
-            * [SimpleSubstitutionCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/SimpleSubstitutionCipherTest.java)
             * [VigenereTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/VigenereTest.java)
           * conversions
             * [BinaryToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java)
diff --git a/src/main/java/com/thealgorithms/ciphers/SimpleSubstitutionCipher.java b/src/main/java/com/thealgorithms/ciphers/SimpleSubstitutionCipher.java
deleted file mode 100644
index 6ce3c564abc7..000000000000
--- a/src/main/java/com/thealgorithms/ciphers/SimpleSubstitutionCipher.java
+++ /dev/null
@@ -1,83 +0,0 @@
-package com.thealgorithms.ciphers;
-
-import java.util.HashMap;
-import java.util.Map;
-
-/**
- * The simple substitution cipher is a cipher that has been in use for many
- * hundreds of years (an excellent history is given in Simon Singhs 'the Code
- * Book'). It basically consists of substituting every plaintext character for a
- * different ciphertext character. It differs from the Caesar cipher in that the
- * cipher alphabet is not simply the alphabet shifted, it is completely jumbled.
- *
- * @author Hassan Elseoudy
- */
-public class SimpleSubstitutionCipher {
-
-    /**
-     * Encrypt text by replacing each element with its opposite character.
-     *
-     * @return Encrypted message
-     */
-    public static String encode(String message, String cipherSmall) {
-        StringBuilder encoded = new StringBuilder();
-
-        // This map is used to encode
-        Map<Character, Character> cipherMap = new HashMap<>();
-
-        char beginSmallLetter = 'a';
-        char beginCapitalLetter = 'A';
-
-        cipherSmall = cipherSmall.toLowerCase();
-        String cipherCapital = cipherSmall.toUpperCase();
-
-        // To handle Small and Capital letters
-        for (int i = 0; i < cipherSmall.length(); i++) {
-            cipherMap.put(beginSmallLetter++, cipherSmall.charAt(i));
-            cipherMap.put(beginCapitalLetter++, cipherCapital.charAt(i));
-        }
-
-        for (int i = 0; i < message.length(); i++) {
-            if (Character.isAlphabetic(message.charAt(i))) {
-                encoded.append(cipherMap.get(message.charAt(i)));
-            } else {
-                encoded.append(message.charAt(i));
-            }
-        }
-
-        return encoded.toString();
-    }
-
-    /**
-     * Decrypt message by replacing each element with its opposite character in
-     * cipher.
-     *
-     * @return message
-     */
-    public static String decode(String encryptedMessage, String cipherSmall) {
-        StringBuilder decoded = new StringBuilder();
-
-        Map<Character, Character> cipherMap = new HashMap<>();
-
-        char beginSmallLetter = 'a';
-        char beginCapitalLetter = 'A';
-
-        cipherSmall = cipherSmall.toLowerCase();
-        String cipherCapital = cipherSmall.toUpperCase();
-
-        for (int i = 0; i < cipherSmall.length(); i++) {
-            cipherMap.put(cipherSmall.charAt(i), beginSmallLetter++);
-            cipherMap.put(cipherCapital.charAt(i), beginCapitalLetter++);
-        }
-
-        for (int i = 0; i < encryptedMessage.length(); i++) {
-            if (Character.isAlphabetic(encryptedMessage.charAt(i))) {
-                decoded.append(cipherMap.get(encryptedMessage.charAt(i)));
-            } else {
-                decoded.append(encryptedMessage.charAt(i));
-            }
-        }
-
-        return decoded.toString();
-    }
-}
diff --git a/src/test/java/com/thealgorithms/ciphers/SimpleSubstitutionCipherTest.java b/src/test/java/com/thealgorithms/ciphers/SimpleSubstitutionCipherTest.java
deleted file mode 100644
index f7cace2e08aa..000000000000
--- a/src/test/java/com/thealgorithms/ciphers/SimpleSubstitutionCipherTest.java
+++ /dev/null
@@ -1,48 +0,0 @@
-package com.thealgorithms.ciphers;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.api.Test;
-
-public class SimpleSubstitutionCipherTest {
-
-    @Test
-    void testEncode() {
-        // Given
-        String message = "HELLOWORLD";
-        String key = "phqgiumeaylnofdxjkrcvstzwb";
-
-        // When
-        String actual = SimpleSubstitutionCipher.encode(message, key);
-
-        // Then
-        assertEquals("EINNDTDKNG", actual);
-    }
-
-    @Test
-    void testDecode() {
-        // Given
-        String message = "EINNDTDKNG";
-        String key = "phqgiumeaylnofdxjkrcvstzwb";
-
-        // When
-        String actual = SimpleSubstitutionCipher.decode(message, key);
-
-        // Then
-        assertEquals("HELLOWORLD", actual);
-    }
-
-    @Test
-    void testIsTextTheSameAfterEncodeAndDecode() {
-        // Given
-        String text = "HELLOWORLD";
-        String key = "phqgiumeaylnofdxjkrcvstzwb";
-
-        // When
-        String encodedText = SimpleSubstitutionCipher.encode(text, key);
-        String decodedText = SimpleSubstitutionCipher.decode(encodedText, key);
-
-        // Then
-        assertEquals(text, decodedText);
-    }
-}

From a7d140a43e03821728f919f2402b006ae985cfa5 Mon Sep 17 00:00:00 2001
From: Nishant Jain <121454072+inishantjain@users.noreply.github.com>
Date: Tue, 2 Jan 2024 23:48:01 +0530
Subject: [PATCH 0078/1338] Add Set Kth Bit (#4990)

---
 .../bitmanipulation/SetKthBit.java            | 22 ++++++++++++++++++
 .../bitmanipulation/SetKthBitTest.java        | 23 +++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java b/src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java
new file mode 100644
index 000000000000..3c4e50d1d38d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.bitmanipulation;
+
+/***
+ * Sets the kth bit of a given integer to 1
+ * e.g. setting 3rd bit in binary of 17 (binary 10001) gives 25 (binary 11001)
+ * @author inishantjain
+ */
+
+public class SetKthBit {
+    /**
+     * Sets the kth bit of a given integer.
+     *
+     * @param num The original integer.
+     * @param k   The position of the bit to set (0-based index).
+     * @return The integer with the kth bit set.
+     */
+    public static int setKthBit(int num, int k) {
+        int mask = 1 << k;
+        num = num | mask;
+        return num;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java b/src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java
new file mode 100644
index 000000000000..35d5fa35da54
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class SetKthBitTest {
+
+    @Test
+    void testSetKthBit() {
+        // Test case: Setting the 0th bit in 5 (binary 101)
+        assertEquals(5, SetKthBit.setKthBit(5, 0));
+
+        // Test case: Setting the 2nd bit in 10 (binary 1010)
+        assertEquals(14, SetKthBit.setKthBit(10, 2));
+
+        // Test case: Setting the 3rd bit in 15 (binary 1111)
+        assertEquals(15, SetKthBit.setKthBit(15, 3));
+
+        // Test case: Setting the 1st bit in 0 (binary 0)
+        assertEquals(2, SetKthBit.setKthBit(0, 1));
+    }
+}

From 9bef5a169c2295eee0c377db1f5afa0141bceb79 Mon Sep 17 00:00:00 2001
From: Govind Gupta <102366719+Govind516@users.noreply.github.com>
Date: Wed, 3 Jan 2024 18:44:38 +0530
Subject: [PATCH 0079/1338] Add Playfair Cipher (#4988)

---
 DIRECTORY.md                                  |   4 +
 .../thealgorithms/ciphers/PlayfairCipher.java | 128 ++++++++++++++++++
 .../thealgorithms/ciphers/PlayfairTest.java   |  37 +++++
 3 files changed, 169 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/PlayfairTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index fd50b2914cff..b621216da7f1 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -27,6 +27,7 @@
             * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
             * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
+            * [SetKthBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java)
             * [SingleBitOperations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java)
           * ciphers
             * a5
@@ -44,6 +45,7 @@
             * [ColumnarTranspositionCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java)
             * [DES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/DES.java)
             * [HillCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/HillCipher.java)
+            * [PlayfairCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java)
             * [Polybius](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Polybius.java)
             * [ProductCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ProductCipher.java)
             * [RSA](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/RSA.java)
@@ -585,6 +587,7 @@
             * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
             * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
+            * [SetKthBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java)
             * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
           * ciphers
             * a5
@@ -592,6 +595,7 @@
             * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
             * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
             * [DESTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DESTest.java)
+            * [PlayfairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java)
             * [PolybiusTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
             * [RSATest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RSATest.java)
             * [SimpleSubCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/SimpleSubCipherTest.java)
diff --git a/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java b/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java
new file mode 100644
index 000000000000..76ceb6dbce31
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java
@@ -0,0 +1,128 @@
+package com.thealgorithms.ciphers;
+
+public class PlayfairCipher {
+
+    private char[][] matrix;
+    private String key;
+
+    public PlayfairCipher(String key) {
+        this.key = key;
+        generateMatrix();
+    }
+
+    public String encrypt(String plaintext) {
+        plaintext = prepareText(plaintext.replace("J", "I"));
+        StringBuilder ciphertext = new StringBuilder();
+        for (int i = 0; i < plaintext.length(); i += 2) {
+            char char1 = plaintext.charAt(i);
+            char char2 = plaintext.charAt(i + 1);
+            int[] pos1 = findPosition(char1);
+            int[] pos2 = findPosition(char2);
+            int row1 = pos1[0];
+            int col1 = pos1[1];
+            int row2 = pos2[0];
+            int col2 = pos2[1];
+            if (row1 == row2) {
+                ciphertext.append(matrix[row1][(col1 + 1) % 5]);
+                ciphertext.append(matrix[row2][(col2 + 1) % 5]);
+            } else if (col1 == col2) {
+                ciphertext.append(matrix[(row1 + 1) % 5][col1]);
+                ciphertext.append(matrix[(row2 + 1) % 5][col2]);
+            } else {
+                ciphertext.append(matrix[row1][col2]);
+                ciphertext.append(matrix[row2][col1]);
+            }
+        }
+        return ciphertext.toString();
+    }
+
+    public String decrypt(String ciphertext) {
+        StringBuilder plaintext = new StringBuilder();
+        for (int i = 0; i < ciphertext.length(); i += 2) {
+            char char1 = ciphertext.charAt(i);
+            char char2 = ciphertext.charAt(i + 1);
+            int[] pos1 = findPosition(char1);
+            int[] pos2 = findPosition(char2);
+            int row1 = pos1[0];
+            int col1 = pos1[1];
+            int row2 = pos2[0];
+            int col2 = pos2[1];
+            if (row1 == row2) {
+                plaintext.append(matrix[row1][(col1 + 4) % 5]);
+                plaintext.append(matrix[row2][(col2 + 4) % 5]);
+            } else if (col1 == col2) {
+                plaintext.append(matrix[(row1 + 4) % 5][col1]);
+                plaintext.append(matrix[(row2 + 4) % 5][col2]);
+            } else {
+                plaintext.append(matrix[row1][col2]);
+                plaintext.append(matrix[row2][col1]);
+            }
+        }
+        return plaintext.toString();
+    }
+
+    private void generateMatrix() {
+        String keyWithoutDuplicates = removeDuplicateChars(key + "ABCDEFGHIKLMNOPQRSTUVWXYZ");
+        matrix = new char[5][5];
+        int index = 0;
+        for (int i = 0; i < 5; i++) {
+            for (int j = 0; j < 5; j++) {
+                matrix[i][j] = keyWithoutDuplicates.charAt(index);
+                index++;
+            }
+        }
+    }
+
+    private String removeDuplicateChars(String str) {
+        StringBuilder result = new StringBuilder();
+        for (int i = 0; i < str.length(); i++) {
+            if (result.indexOf(String.valueOf(str.charAt(i))) == -1) {
+                result.append(str.charAt(i));
+            }
+        }
+        return result.toString();
+    }
+
+    private String prepareText(String text) {
+        text = text.toUpperCase().replaceAll("[^A-Z]", "");
+        StringBuilder preparedText = new StringBuilder();
+        char prevChar = '\0';
+        for (char c : text.toCharArray()) {
+            if (c != prevChar) {
+                preparedText.append(c);
+                prevChar = c;
+            } else {
+                preparedText.append('X').append(c);
+                prevChar = '\0';
+            }
+        }
+        if (preparedText.length() % 2 != 0) {
+            preparedText.append('X');
+        }
+        return preparedText.toString();
+    }
+
+    private int[] findPosition(char c) {
+        int[] pos = new int[2];
+        for (int i = 0; i < 5; i++) {
+            for (int j = 0; j < 5; j++) {
+                if (matrix[i][j] == c) {
+                    pos[0] = i;
+                    pos[1] = j;
+                    return pos;
+                }
+            }
+        }
+        return pos;
+    }
+
+    public void printMatrix() {
+        System.out.println("\nPlayfair Cipher Matrix:");
+        for (int i = 0; i < 5; i++) {
+            for (int j = 0; j < 5; j++) {
+                System.out.print(matrix[i][j] + " ");
+            }
+            System.out.println();
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java b/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java
new file mode 100644
index 000000000000..5562241b48db
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java
@@ -0,0 +1,37 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class PlayfairTest {
+
+    @Test
+    public void testEncryption() {
+        PlayfairCipher playfairCipher = new PlayfairCipher("KEYWORD");
+
+        String plaintext = "HELLO";
+        String encryptedText = playfairCipher.encrypt(plaintext);
+        assertEquals("GYIZSC", encryptedText);
+    }
+
+    @Test
+    public void testDecryption() {
+        PlayfairCipher playfairCipher = new PlayfairCipher("KEYWORD");
+
+        String encryptedText = "UDRIYP";
+        String decryptedText = playfairCipher.decrypt(encryptedText);
+        assertEquals("NEBFVH", decryptedText);
+    }
+
+    @Test
+    public void testEncryptionAndDecryption() {
+        PlayfairCipher playfairCipher = new PlayfairCipher("KEYWORD");
+
+        String plaintext = "PLAYFAIR";
+        String encryptedText = playfairCipher.encrypt(plaintext);
+        String decryptedText = playfairCipher.decrypt(encryptedText);
+
+        assertEquals(plaintext, decryptedText);
+    }
+}

From 6a0c0585e4530f0c9cfd207ffe825c5acc3f022f Mon Sep 17 00:00:00 2001
From: AthinaSw <152101068+AthinaSw@users.noreply.github.com>
Date: Wed, 3 Jan 2024 20:11:07 +0200
Subject: [PATCH 0080/1338] Add cross-correlation and auto-correlation (#4984)

---
 .../thealgorithms/maths/AutoCorrelation.java  | 55 ++++++++++++
 .../thealgorithms/maths/CrossCorrelation.java | 87 +++++++++++++++++++
 .../maths/AutoCorrelationTest.java            | 37 ++++++++
 .../maths/CrossCorrelationTest.java           | 37 ++++++++
 4 files changed, 216 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/AutoCorrelation.java
 create mode 100644 src/main/java/com/thealgorithms/maths/CrossCorrelation.java
 create mode 100644 src/test/java/com/thealgorithms/maths/AutoCorrelationTest.java
 create mode 100644 src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java

diff --git a/src/main/java/com/thealgorithms/maths/AutoCorrelation.java b/src/main/java/com/thealgorithms/maths/AutoCorrelation.java
new file mode 100644
index 000000000000..5b38235bcd01
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/AutoCorrelation.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.maths;
+
+/**
+ * Class for linear auto-correlation of a discrete signal
+ *
+ * @author Athina-Frederiki Swinkels
+ * @version 2.0
+ */
+
+public class AutoCorrelation {
+
+    /**
+     * Discrete linear auto-correlation function.
+     * Input and output signals have starting index 0.
+     *
+     * @param x The discrete signal
+     * @return The result of the auto-correlation of signals x. The result is also a signal.
+     */
+    public static double[] autoCorrelation(double[] x) {
+
+        /*
+        To find the auto-correlation of a discrete signal x, we perform cross-correlation between x signal and itself.
+        Here's an example:
+        x=[1,2,1,1]
+        y=[1,2,1,1]
+
+        i=0:      [1,2,1,1]
+            [1,2,1,1]               result[0]=1*1=1
+
+        i=1:       [1,2,1,1]
+               [1,2,1,1]            result[1]=1*1+2*1=3
+
+        i=2:       [1,2,1,1]
+                 [1,2,1,1]          result[2]=1*2+2*1+1*1=5
+
+        i=3:       [1,2,1,1]
+                   [1,2,1,1]        result[3]=1*1+2*2+1*1+1*1=7
+
+        i=4:       [1,2,1,1]
+                     [1,2,1,1]      result[4]=2*1+1*2+1*1=5
+
+        i=5:       [1,2,1,1]
+                       [1,2,1,1]    result[5]=1*1+1*2=3
+
+        i=1:       [1,2,1,1]
+                         [1,2,1,1]  result[6]=1*1=1
+
+        result=[1,3,5,7,5,3,1]
+
+
+         */
+
+        return CrossCorrelation.crossCorrelation(x, x);
+    }
+}
diff --git a/src/main/java/com/thealgorithms/maths/CrossCorrelation.java b/src/main/java/com/thealgorithms/maths/CrossCorrelation.java
new file mode 100644
index 000000000000..080e4ab7e74b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/CrossCorrelation.java
@@ -0,0 +1,87 @@
+package com.thealgorithms.maths;
+
+/**
+ * Class for linear cross-correlation of two discrete signals
+ *
+ * @author Athina-Frederiki Swinkels
+ * @version 1.0
+ */
+
+public class CrossCorrelation {
+
+    /**
+     * Discrete linear cross-correlation function.
+     * Input and output signals have starting index 0.
+     *
+     * @param x The first discrete signal
+     * @param y The second discrete signal
+     * @return The result of the cross-correlation of signals x,y. The result is also a signal.
+     */
+    public static double[] crossCorrelation(double[] x, double[] y) {
+        // The result signal's length is the sum of the input signals' lengths minus 1
+        double[] result = new double[x.length + y.length - 1];
+        int N = result.length;
+
+        /*
+        To find the cross-correlation between 2 discrete signals x & y, we start by "placing" the second signal
+        y under the first signal x, shifted to the left so that the last value of y meets the first value of x
+        and for every new position (i++) of the result signal, we shift y signal one position to the right, until
+        the first y-value meets the last x-value. The result-value for each position is the sum of all x*y meeting
+        values.
+        Here's an example:
+        x=[1,2,1,1]
+        y=[1,1,2,1]
+
+        i=0:      [1,2,1,1]
+            [1,1,2,1]               result[0]=1*1=1
+
+        i=1:       [1,2,1,1]
+               [1,1,2,1]            result[1]=1*2+2*1=4
+
+        i=2:       [1,2,1,1]
+                 [1,1,2,1]          result[2]=1*1+2*2+1*1=6
+
+        i=3:       [1,2,1,1]
+                   [1,1,2,1]        result[3]=1*1+2*1+1*2+1*1=6
+
+        i=4:       [1,2,1,1]
+                     [1,1,2,1]      result[4]=2*1+1*1+1*2=5
+
+        i=5:       [1,2,1,1]
+                       [1,1,2,1]    result[5]=1*1+1*1=2
+
+        i=1:       [1,2,1,1]
+                         [1,1,2,1]  result[6]=1*1=1
+
+        result=[1,4,6,6,5,2,1]
+
+
+
+
+        To find the result[i] value for each i:0->N-1, the positions of x-signal in which the 2 signals meet
+        are calculated: kMin<=k<=kMax.
+        The variable 'yStart' indicates the starting index of y in each sum calculation.
+        The variable 'count' increases the index of y-signal by 1, to move to the next value.
+         */
+        int yStart = y.length;
+        for (int i = 0; i < N; i++) {
+            result[i] = 0;
+
+            int kMin = Math.max(i - (y.length - 1), 0);
+            int kMax = Math.min(i, x.length - 1);
+
+            if (i < y.length) {
+                yStart--;
+            }
+
+            int count = 0;
+            for (int k = kMin; k <= kMax; k++) {
+                result[i] += x[k] * y[yStart + count];
+                count++;
+            }
+        }
+
+        // The calculated cross-correlation of x & y signals is returned here.
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/AutoCorrelationTest.java b/src/test/java/com/thealgorithms/maths/AutoCorrelationTest.java
new file mode 100644
index 000000000000..cacfe5904faa
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/AutoCorrelationTest.java
@@ -0,0 +1,37 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+/**
+ * Test class for AutoCorrelation class
+ *
+ * @author Athina-Frederiki Swinkels
+ * @version 2.0
+ */
+
+public class AutoCorrelationTest {
+
+    @ParameterizedTest
+    @CsvSource({"1;2;1;1, 1;3;5;7;5;3;1", "1;2;3, 3;8;14;8;3", "1.5;2.3;3.1;4.2, 6.3;14.31;23.6;34.79;23.6;14.31;6.3"})
+
+    public void testAutoCorrelationParameterized(String input, String expected) {
+        double[] array = convertStringToArray(input);
+        double[] expectedResult = convertStringToArray(expected);
+
+        double[] result = AutoCorrelation.autoCorrelation(array);
+
+        assertArrayEquals(expectedResult, result, 0.0001);
+    }
+
+    private double[] convertStringToArray(String input) {
+        String[] elements = input.split(";");
+        double[] result = new double[elements.length];
+        for (int i = 0; i < elements.length; i++) {
+            result[i] = Double.parseDouble(elements[i]);
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java b/src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java
new file mode 100644
index 000000000000..a7e4f14fb3af
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java
@@ -0,0 +1,37 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+/**
+ * Test class for CrossCorrelation class
+ *
+ * @author Athina-Frederiki Swinkels
+ * @version 2.0
+ */
+public class CrossCorrelationTest {
+
+    @ParameterizedTest
+    @CsvSource({"1;2;1;1, 1;1;2;1, 1;4;6;6;5;2;1", "1;2;3, 1;2;3;4;5, 5;14;26;20;14;8;3", "1;2;3;4;5, 1;2;3, 3;8;14;20;26;14;5", "1.5;2.3;3.1;4.2, 1.1;2.2;3.3, 4.95;10.89;16.94;23.21;12.65;4.62"})
+
+    public void testCrossCorrelationParameterized(String input1, String input2, String expected) {
+        double[] array1 = convertStringToArray(input1);
+        double[] array2 = convertStringToArray(input2);
+        double[] expectedResult = convertStringToArray(expected);
+
+        double[] result = CrossCorrelation.crossCorrelation(array1, array2);
+
+        assertArrayEquals(expectedResult, result, 0.0001);
+    }
+
+    private double[] convertStringToArray(String input) {
+        String[] elements = input.split(";");
+        double[] result = new double[elements.length];
+        for (int i = 0; i < elements.length; i++) {
+            result[i] = Double.parseDouble(elements[i]);
+        }
+        return result;
+    }
+}

From 092ac5795bc2004c04032fc2b79ee892e2ffcb05 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 3 Jan 2024 23:28:59 +0100
Subject: [PATCH 0081/1338] Remove `SetKthBit` in favor of
 `SingleBitOperations.setBit` (#4991)

---
 .../bitmanipulation/SetKthBit.java            | 22 ------
 .../bitmanipulation/SetKthBitTest.java        | 23 -------
 .../SingleBitOperationsTest.java              | 68 ++++++++++---------
 3 files changed, 36 insertions(+), 77 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java
 delete mode 100644 src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java b/src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java
deleted file mode 100644
index 3c4e50d1d38d..000000000000
--- a/src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java
+++ /dev/null
@@ -1,22 +0,0 @@
-package com.thealgorithms.bitmanipulation;
-
-/***
- * Sets the kth bit of a given integer to 1
- * e.g. setting 3rd bit in binary of 17 (binary 10001) gives 25 (binary 11001)
- * @author inishantjain
- */
-
-public class SetKthBit {
-    /**
-     * Sets the kth bit of a given integer.
-     *
-     * @param num The original integer.
-     * @param k   The position of the bit to set (0-based index).
-     * @return The integer with the kth bit set.
-     */
-    public static int setKthBit(int num, int k) {
-        int mask = 1 << k;
-        num = num | mask;
-        return num;
-    }
-}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java b/src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java
deleted file mode 100644
index 35d5fa35da54..000000000000
--- a/src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java
+++ /dev/null
@@ -1,23 +0,0 @@
-package com.thealgorithms.bitmanipulation;
-
-import static org.junit.jupiter.api.Assertions.*;
-
-import org.junit.jupiter.api.Test;
-
-class SetKthBitTest {
-
-    @Test
-    void testSetKthBit() {
-        // Test case: Setting the 0th bit in 5 (binary 101)
-        assertEquals(5, SetKthBit.setKthBit(5, 0));
-
-        // Test case: Setting the 2nd bit in 10 (binary 1010)
-        assertEquals(14, SetKthBit.setKthBit(10, 2));
-
-        // Test case: Setting the 3rd bit in 15 (binary 1111)
-        assertEquals(15, SetKthBit.setKthBit(15, 3));
-
-        // Test case: Setting the 1st bit in 0 (binary 0)
-        assertEquals(2, SetKthBit.setKthBit(0, 1));
-    }
-}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java
index a6bb76689ec8..9cac8d670a4a 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java
@@ -1,32 +1,36 @@
-package com.thealgorithms.bitmanipulation;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.api.Test;
-
-public class SingleBitOperationsTest {
-
-    @Test
-    public void flipBitTest() {
-        assertEquals(1, SingleBitOperations.flipBit(3, 1));
-        assertEquals(11, SingleBitOperations.flipBit(3, 3));
-    }
-
-    @Test
-    public void setBitTest() {
-        assertEquals(5, SingleBitOperations.setBit(4, 0));
-        assertEquals(4, SingleBitOperations.setBit(4, 2));
-    }
-
-    @Test
-    public void clearBitTest() {
-        assertEquals(5, SingleBitOperations.clearBit(7, 1));
-        assertEquals(5, SingleBitOperations.clearBit(5, 1));
-    }
-
-    @Test
-    public void getBitTest() {
-        assertEquals(0, SingleBitOperations.getBit(6, 0));
-        assertEquals(1, SingleBitOperations.getBit(7, 1));
-    }
-}
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class SingleBitOperationsTest {
+
+    @Test
+    public void flipBitTest() {
+        assertEquals(1, SingleBitOperations.flipBit(3, 1));
+        assertEquals(11, SingleBitOperations.flipBit(3, 3));
+    }
+
+    @Test
+    public void setBitTest() {
+        assertEquals(5, SingleBitOperations.setBit(4, 0));
+        assertEquals(4, SingleBitOperations.setBit(4, 2));
+        assertEquals(5, SingleBitOperations.setBit(5, 0));
+        assertEquals(14, SingleBitOperations.setBit(10, 2));
+        assertEquals(15, SingleBitOperations.setBit(15, 3));
+        assertEquals(2, SingleBitOperations.setBit(0, 1));
+    }
+
+    @Test
+    public void clearBitTest() {
+        assertEquals(5, SingleBitOperations.clearBit(7, 1));
+        assertEquals(5, SingleBitOperations.clearBit(5, 1));
+    }
+
+    @Test
+    public void getBitTest() {
+        assertEquals(0, SingleBitOperations.getBit(6, 0));
+        assertEquals(1, SingleBitOperations.getBit(7, 1));
+    }
+}

From 1ea95ffa928e42bda532380233a9667764dafdf5 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 4 Jan 2024 11:56:48 +0100
Subject: [PATCH 0082/1338] Cleanup `PerfectSquare` and its tests (#4992)

---
 .../thealgorithms/maths/PerfectSquare.java    | 14 ++-----
 .../maths/PerfectSquareTest.java              | 41 ++++++-------------
 2 files changed, 16 insertions(+), 39 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/PerfectSquare.java b/src/main/java/com/thealgorithms/maths/PerfectSquare.java
index 702e62943d88..fbc7a6f19bd0 100644
--- a/src/main/java/com/thealgorithms/maths/PerfectSquare.java
+++ b/src/main/java/com/thealgorithms/maths/PerfectSquare.java
@@ -3,14 +3,8 @@
 /**
  * https://en.wikipedia.org/wiki/Perfect_square
  */
-public class PerfectSquare {
-
-    public static void main(String[] args) {
-        assert !isPerfectSquare(-1);
-        assert !isPerfectSquare(3);
-        assert !isPerfectSquare(5);
-        assert isPerfectSquare(9);
-        assert isPerfectSquare(100);
+public final class PerfectSquare {
+    private PerfectSquare() {
     }
 
     /**
@@ -20,8 +14,8 @@ public static void main(String[] args) {
      * @return <tt>true</tt> if {@code number} is perfect square, otherwise
      * <tt>false</tt>
      */
-    public static boolean isPerfectSquare(int number) {
-        int sqrt = (int) Math.sqrt(number);
+    public static boolean isPerfectSquare(final int number) {
+        final int sqrt = (int) Math.sqrt(number);
         return sqrt * sqrt == number;
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java b/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java
index 487b477816fd..450ba972debe 100644
--- a/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java
+++ b/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java
@@ -1,38 +1,21 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
-
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 public class PerfectSquareTest {
-
-    @Test
-    public void TestPerfectSquareifiscorrect() {
-        // Valid Partition
-        int number = 9;
-
-        boolean result = PerfectSquare.isPerfectSquare(number);
-
-        assertTrue(result);
-    }
-
-    @Test
-    public void TestPerfectSquareifisnotcorrect() {
-        // Invalid Partition 1
-        int number = 3;
-
-        boolean result = PerfectSquare.isPerfectSquare(number);
-
-        assertFalse(result);
+    @ParameterizedTest
+    @ValueSource(ints = {0, 1, 2 * 2, 3 * 3, 4 * 4, 5 * 5, 6 * 6, 7 * 7, 8 * 8, 9 * 9, 10 * 10, 11 * 11, 123 * 123})
+    void positiveTest(final int number) {
+        Assertions.assertTrue(PerfectSquare.isPerfectSquare(number));
     }
 
-    @Test
-    public void TestPerfectSquareifisNegativeNumber() {
-        // Invalid Partition 2
-        int number = -10;
-
-        boolean result = PerfectSquare.isPerfectSquare(number);
-
-        assertFalse(result);
+    @ParameterizedTest
+    @ValueSource(ints = {-1, -2, -3, -4, -5, -100, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 17, 99, 101, 257, 999, 1001})
+    void negativeTest(final int number) {
+        Assertions.assertFalse(PerfectSquare.isPerfectSquare(number));
     }
 }

From 8930ab5b16ad3ab062c22004dbfc3da701bb85ef Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 5 Jan 2024 22:05:52 +0100
Subject: [PATCH 0083/1338] Cleanup `SumOfDigits` and its tests (#4994)

---
 .../com/thealgorithms/maths/SumOfDigits.java  | 35 +++++-----------
 .../thealgorithms/maths/SumOfDigitsTest.java  | 40 +++++++++----------
 2 files changed, 31 insertions(+), 44 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/SumOfDigits.java b/src/main/java/com/thealgorithms/maths/SumOfDigits.java
index 09b690facdb9..e5ec8a02025d 100644
--- a/src/main/java/com/thealgorithms/maths/SumOfDigits.java
+++ b/src/main/java/com/thealgorithms/maths/SumOfDigits.java
@@ -1,13 +1,7 @@
 package com.thealgorithms.maths;
 
-public class SumOfDigits {
-
-    public static void main(String[] args) {
-        assert sumOfDigits(-123) == 6 && sumOfDigitsRecursion(-123) == 6 && sumOfDigitsFast(-123) == 6;
-
-        assert sumOfDigits(0) == 0 && sumOfDigitsRecursion(0) == 0 && sumOfDigitsFast(0) == 0;
-
-        assert sumOfDigits(12345) == 15 && sumOfDigitsRecursion(12345) == 15 && sumOfDigitsFast(12345) == 15;
+public final class SumOfDigits {
+    private SumOfDigits() {
     }
 
     /**
@@ -17,12 +11,12 @@ public static void main(String[] args) {
      * @return sum of digits of given {@code number}
      */
     public static int sumOfDigits(int number) {
-        number = number < 0 ? -number : number;
-        /* calculate abs value */
+        final int base = 10;
+        number = Math.abs(number);
         int sum = 0;
         while (number != 0) {
-            sum += number % 10;
-            number /= 10;
+            sum += number % base;
+            number /= base;
         }
         return sum;
     }
@@ -34,9 +28,9 @@ public static int sumOfDigits(int number) {
      * @return sum of digits of given {@code number}
      */
     public static int sumOfDigitsRecursion(int number) {
-        number = number < 0 ? -number : number;
-        /* calculate abs value */
-        return number < 10 ? number : number % 10 + sumOfDigitsRecursion(number / 10);
+        final int base = 10;
+        number = Math.abs(number);
+        return number < base ? number : number % base + sumOfDigitsRecursion(number / base);
     }
 
     /**
@@ -45,14 +39,7 @@ public static int sumOfDigitsRecursion(int number) {
      * @param number the number contains digits
      * @return sum of digits of given {@code number}
      */
-    public static int sumOfDigitsFast(int number) {
-        number = number < 0 ? -number : number;
-        /* calculate abs value */
-        char[] digits = (number + "").toCharArray();
-        int sum = 0;
-        for (int i = 0; i < digits.length; ++i) {
-            sum += digits[i] - '0';
-        }
-        return sum;
+    public static int sumOfDigitsFast(final int number) {
+        return String.valueOf(Math.abs(number)).chars().map(c -> c - '0').reduce(0, Integer::sum);
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/SumOfDigitsTest.java b/src/test/java/com/thealgorithms/maths/SumOfDigitsTest.java
index 1c3b56b7ee5e..76aca44a2220 100644
--- a/src/test/java/com/thealgorithms/maths/SumOfDigitsTest.java
+++ b/src/test/java/com/thealgorithms/maths/SumOfDigitsTest.java
@@ -1,31 +1,31 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
-
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class SumOfDigitsTest {
+    @ParameterizedTest
+    @MethodSource("testCases")
+    void sumOfDigitsTest(final int expected, final int input) {
+        Assertions.assertEquals(expected, SumOfDigits.sumOfDigits(input));
+    }
 
-    SumOfDigits SoD = new SumOfDigits();
-
-    @Test
-    void testZero() {
-        assertEquals(0, SumOfDigits.sumOfDigits(0));
-        assertEquals(0, SumOfDigits.sumOfDigitsRecursion(0));
-        assertEquals(0, SumOfDigits.sumOfDigitsFast(0));
+    @ParameterizedTest
+    @MethodSource("testCases")
+    void sumOfDigitsRecursionTest(final int expected, final int input) {
+        Assertions.assertEquals(expected, SumOfDigits.sumOfDigitsRecursion(input));
     }
 
-    @Test
-    void testPositive() {
-        assertEquals(15, SumOfDigits.sumOfDigits(12345));
-        assertEquals(15, SumOfDigits.sumOfDigitsRecursion(12345));
-        assertEquals(15, SumOfDigits.sumOfDigitsFast(12345));
+    @ParameterizedTest
+    @MethodSource("testCases")
+    void sumOfDigitsFastTest(final int expected, final int input) {
+        Assertions.assertEquals(expected, SumOfDigits.sumOfDigitsFast(input));
     }
 
-    @Test
-    void testNegative() {
-        assertEquals(6, SumOfDigits.sumOfDigits(-123));
-        assertEquals(6, SumOfDigits.sumOfDigitsRecursion(-123));
-        assertEquals(6, SumOfDigits.sumOfDigitsFast(-123));
+    private static Stream<Arguments> testCases() {
+        return Stream.of(Arguments.of(0, 0), Arguments.of(1, 1), Arguments.of(15, 12345), Arguments.of(6, -123), Arguments.of(1, -100000), Arguments.of(8, 512));
     }
 }

From 704b5878b660535477370a8f2d8c9d5175169302 Mon Sep 17 00:00:00 2001
From: "Tung Bui (Leo)" <tung.bquang@gmail.com>
Date: Sun, 7 Jan 2024 19:20:43 +0700
Subject: [PATCH 0084/1338] Use Discord channel in stale issue/PR message
 (#5004)

---
 .github/workflows/stale.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index 8fbb262b9e36..ee14629b2e41 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -8,10 +8,10 @@ jobs:
     steps:
       - uses: actions/stale@v4
         with:
-          stale-issue-message: 'This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.'
-          close-issue-message: 'Please reopen this issue once you add more information and updates here. If this is not the case and you need some help, feel free to seek help from our [Gitter](https://gitter.im/TheAlgorithms) or ping one of the reviewers. Thank you for your contributions!'
-          stale-pr-message: 'This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.'
-          close-pr-message: 'Please reopen this pull request once you commit the changes requested or make improvements on the code. If this is not the case and you need some help, feel free to seek help from our [Gitter](https://gitter.im/TheAlgorithms) or ping one of the reviewers. Thank you for your contributions!'
+          stale-issue-message: 'This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution!'
+          close-issue-message: 'Please reopen this issue once you have made the required changes. If you need help, feel free to ask in our [Discord](https://the-algorithms.com/discord) server or ping one of the maintainers here. Thank you for your contribution!'
+          stale-pr-message: 'This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution!'
+          close-pr-message: 'Please reopen this pull request once you have made the required changes. If you need help, feel free to ask in our [Discord](https://the-algorithms.com/discord) server or ping one of the maintainers here. Thank you for your contribution!'
           exempt-issue-labels: 'dont-close'
           exempt-pr-labels: 'dont-close'
           days-before-stale: 30

From 0c881e39f24152a47ba03d4580a5cc8a6d6a69bc Mon Sep 17 00:00:00 2001
From: Nishant Jain <121454072+inishantjain@users.noreply.github.com>
Date: Mon, 8 Jan 2024 19:04:36 +0530
Subject: [PATCH 0085/1338] Simplify minimizing lateness (#4999)

---
 .../greedyalgorithms/MinimizingLateness.java  | 43 +++++++++++++++
 .../MinimizingLateness.java                   | 55 -------------------
 .../minimizinglateness/lateness_data.txt      |  7 ---
 .../MinimizingLatenessTest.java               | 43 +++++++++++++++
 4 files changed, 86 insertions(+), 62 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java
 delete mode 100644 src/main/java/com/thealgorithms/minimizinglateness/MinimizingLateness.java
 delete mode 100644 src/main/java/com/thealgorithms/minimizinglateness/lateness_data.txt
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java

diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java b/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java
new file mode 100644
index 000000000000..938ae79bb625
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java
@@ -0,0 +1,43 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.Arrays;
+
+public class MinimizingLateness {
+
+    public static class Job {
+        String jobName;
+        int startTime = 0;
+        int lateness = 0;
+        int processingTime;
+        int deadline;
+
+        public Job(String jobName, int processingTime, int deadline) {
+            this.jobName = jobName;
+            this.processingTime = processingTime;
+            this.deadline = deadline;
+        }
+
+        public static Job of(String jobName, int processingTime, int deadline) {
+            return new Job(jobName, processingTime, deadline);
+        }
+
+        @Override
+        public String toString() {
+            return String.format("%s, startTime: %d, endTime: %d, lateness: %d", jobName, startTime, processingTime + startTime, lateness);
+        }
+    }
+
+    static void calculateLateness(Job... jobs) {
+
+        // sort the jobs based on their deadline
+        Arrays.sort(jobs, (a, b) -> a.deadline - b.deadline);
+
+        int startTime = 0;
+
+        for (Job job : jobs) {
+            job.startTime = startTime;
+            startTime += job.processingTime;
+            job.lateness = Math.max(0, startTime - job.deadline); // if the job finishes before deadline the lateness is 0
+        }
+    }
+}
diff --git a/src/main/java/com/thealgorithms/minimizinglateness/MinimizingLateness.java b/src/main/java/com/thealgorithms/minimizinglateness/MinimizingLateness.java
deleted file mode 100644
index fc7eae6ae9fc..000000000000
--- a/src/main/java/com/thealgorithms/minimizinglateness/MinimizingLateness.java
+++ /dev/null
@@ -1,55 +0,0 @@
-package com.thealgorithms.minimizinglateness;
-
-import java.io.BufferedReader;
-import java.io.FileReader;
-import java.io.IOException;
-import java.util.StringTokenizer;
-
-public class MinimizingLateness {
-
-    private static class Schedule { // Schedule class
-
-        int t = 0; // Time required for the operation to be performed
-        int d = 0; // Time the job should be completed
-        public Schedule(int t, int d) {
-            this.t = t;
-            this.d = d;
-        }
-    }
-
-    public static void main(String[] args) throws IOException {
-        StringTokenizer token;
-
-        BufferedReader in = new BufferedReader(new FileReader("MinimizingLateness/lateness_data.txt"));
-        String ch = in.readLine();
-        if (ch == null || ch.isEmpty()) {
-            in.close();
-            return;
-        }
-        int indexCount = Integer.parseInt(ch);
-        System.out.println("Input Data : ");
-        System.out.println(indexCount); // number of operations
-        Schedule[] array = new Schedule[indexCount]; // Create an array to hold the operation
-        int i = 0;
-        while ((ch = in.readLine()) != null) {
-            token = new StringTokenizer(ch, " ");
-            // Include the time required for the operation to be performed in the array and the time
-            // it should be completed.
-            array[i] = new Schedule(Integer.parseInt(token.nextToken()), Integer.parseInt(token.nextToken()));
-            i++;
-            System.out.println(array[i - 1].t + " " + array[i - 1].d);
-        }
-
-        int tryTime = 0; // Total time worked
-        int lateness = 0; // Lateness
-        for (int j = 0; j < indexCount - 1; j++) {
-            tryTime = tryTime + array[j].t; // Add total work time
-            // Lateness
-            lateness = lateness + Math.max(0, tryTime - array[j].d);
-        }
-        System.out.println();
-        System.out.println("Output Data : ");
-        System.out.println(lateness);
-        in.close();
-    }
-}
diff --git a/src/main/java/com/thealgorithms/minimizinglateness/lateness_data.txt b/src/main/java/com/thealgorithms/minimizinglateness/lateness_data.txt
deleted file mode 100644
index e2bac0d1cbd0..000000000000
--- a/src/main/java/com/thealgorithms/minimizinglateness/lateness_data.txt
+++ /dev/null
@@ -1,7 +0,0 @@
-6
-3 6
-2 8
-1 9
-4 9
-3 14
-2 15
\ No newline at end of file
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java
new file mode 100644
index 000000000000..04f6900d14db
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java
@@ -0,0 +1,43 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.thealgorithms.greedyalgorithms.MinimizingLateness.Job;
+import org.junit.jupiter.api.Test;
+
+public class MinimizingLatenessTest {
+
+    @Test
+    void testCalculateLateness() {
+        // Test case with three jobs
+        Job job1 = new Job("Job1", 4, 6);
+        Job job2 = new Job("Job2", 2, 8);
+        Job job3 = new Job("Job3", 1, 9);
+        Job job4 = new Job("Job4", 5, 9);
+        Job job5 = new Job("Job5", 4, 10);
+        Job job6 = new Job("Job6", 3, 5);
+
+        MinimizingLateness.calculateLateness(job1, job2, job3, job4, job5, job6);
+
+        // Check lateness for each job
+        assertEquals(6, job4.lateness);
+        assertEquals(0, job6.lateness);
+        assertEquals(1, job2.lateness);
+    }
+
+    @Test
+    void testCheckStartTime() {
+
+        Job job1 = new Job("Job1", 2, 5);
+        Job job2 = new Job("Job2", 1, 7);
+        Job job3 = new Job("Job3", 3, 8);
+        Job job4 = new Job("Job4", 2, 4);
+        Job job5 = new Job("Job5", 4, 10);
+
+        MinimizingLateness.calculateLateness(job1, job2, job3, job4, job5);
+
+        assertEquals(2, job1.startTime);
+        assertEquals(5, job3.startTime);
+        assertEquals(8, job5.startTime);
+    }
+}

From bb2fff0cbb73f91d2b7d43741add059cd219e0a2 Mon Sep 17 00:00:00 2001
From: Nishant Jain <121454072+inishantjain@users.noreply.github.com>
Date: Mon, 8 Jan 2024 19:11:14 +0530
Subject: [PATCH 0086/1338] Add package name (#5007)

---
 .../com/thealgorithms/searches/PerfectBinarySearchTest.java    | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
index 0ba0b03b33b4..ca5829c54495 100644
--- a/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
@@ -1,6 +1,7 @@
+package com.thealgorithms.searches;
+
 import static org.junit.jupiter.api.Assertions.*;
 
-import com.thealgorithms.searches.PerfectBinarySearch;
 import org.junit.jupiter.api.Test;
 
 /**

From c403e0033198adb2b023d01296ea1e3fc7fc2620 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 8 Jan 2024 22:32:18 +0100
Subject: [PATCH 0087/1338] Use `GITHUB_ACTOR` in `git config` (#5009)

---
 .github/workflows/update_directory.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/update_directory.yml b/.github/workflows/update_directory.yml
index 0530a0c267a9..3638e3529e0b 100644
--- a/.github/workflows/update_directory.yml
+++ b/.github/workflows/update_directory.yml
@@ -84,8 +84,8 @@ jobs:
       - name: Update DIRECTORY.md
         run: |
           cat DIRECTORY.md
-          git config --global user.name github-actions
-          git config --global user.email '${GITHUB_ACTOR}@users.noreply.github.com'
+          git config --global user.name "$GITHUB_ACTOR"
+          git config --global user.email "$GITHUB_ACTOR@users.noreply.github.com"
           git remote set-url origin https://x-access-token:${{ secrets.GITHUB_TOKEN }}@github.com/$GITHUB_REPOSITORY
           git add DIRECTORY.md
           git commit -am "Update directory" ||  true

From 570f7e7ef6876a6a5b6a7caf63056680969e3c18 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 8 Jan 2024 22:44:32 +0100
Subject: [PATCH 0088/1338] Remove unused import (#5010)

---
 .../java/com/thealgorithms/strings/ReverseWordsInStringTest.java | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java b/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java
index 44e397459349..7cab6aa7c698 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java
@@ -2,7 +2,6 @@
 
 import java.util.stream.Stream;
 import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;

From fd84b0b10e2e6d17b161e53586164948b69d3b75 Mon Sep 17 00:00:00 2001
From: mpousmali <115431039+mpousmali@users.noreply.github.com>
Date: Mon, 8 Jan 2024 23:48:11 +0200
Subject: [PATCH 0089/1338] Add SRTF Algorithm (#5011)

---
 .gitpod.yml                                   |  1 +
 .../scheduling/SRTFScheduling.java            | 69 +++++++++++++++++++
 .../scheduling/SRTFSchedulingTest.java        | 61 ++++++++++++++++
 3 files changed, 131 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java

diff --git a/.gitpod.yml b/.gitpod.yml
index 4a3944d0023d..21d69f6e2122 100644
--- a/.gitpod.yml
+++ b/.gitpod.yml
@@ -10,3 +10,4 @@ tasks:
 vscode:
   extensions:
     - xaver.clang-format
+
diff --git a/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java b/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java
new file mode 100644
index 000000000000..ad8aeabacad8
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.scheduling;
+
+import com.thealgorithms.devutils.entities.ProcessDetails;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Implementation of Shortest Remaining Time First Scheduling Algorithm.
+ * In the SRTF scheduling algorithm, the process with the smallest amount of time remaining until completion is selected to execute.
+ * Example:
+ * Consider the processes p1, p2 and the following table with info about their arrival and burst time:
+ * Process | Burst Time | Arrival Time
+ * P1      | 6 ms        | 0 ms
+ * P2      | 2 ms        | 1 ms
+ * In this example, P1 will be executed at time = 0 until time = 1 when P2 arrives. At time = 2, P2 will be executed until time = 4. At time 4, P2 is done, and P1 is executed again to be done.
+ * That's a simple example of how the algorithm works.
+ * More information you can find here -> https://en.wikipedia.org/wiki/Shortest_remaining_time
+ */
+public class SRTFScheduling {
+    protected List<ProcessDetails> processes;
+    protected List<String> ready;
+
+    /**
+     * Constructor
+     * @param processes ArrayList of ProcessDetails given as input
+     */
+    public SRTFScheduling(ArrayList<ProcessDetails> processes) {
+        this.processes = new ArrayList<>();
+        ready = new ArrayList<>();
+        this.processes = processes;
+    }
+
+    public void evaluateScheduling() {
+        int time = 0, cr = 0; // cr=current running process, time= units of time
+        int n = processes.size();
+        int[] remainingTime = new int[n];
+
+        /* calculating remaining time of every process and total units of time */
+        for (int i = 0; i < n; i++) {
+            remainingTime[i] = processes.get(i).getBurstTime();
+            time += processes.get(i).getBurstTime();
+        }
+
+        /* if the first process doesn't arrive at 0, we have more units of time */
+        if (processes.get(0).getArrivalTime() != 0) {
+            time += processes.get(0).getArrivalTime();
+        }
+
+        /* printing id of the process which is executed at every unit of time */
+        // if the first process doesn't arrive at 0, we print only \n until it arrives
+        if (processes.get(0).getArrivalTime() != 0) {
+            for (int i = 0; i < processes.get(0).getArrivalTime(); i++) {
+                ready.add(null);
+            }
+        }
+
+        for (int i = processes.get(0).getArrivalTime(); i < time; i++) {
+            /* checking if there's a process with remaining time less than current running process.
+               If we find it, then it executes. */
+            for (int j = 0; j < n; j++) {
+                if (processes.get(j).getArrivalTime() <= i && (remainingTime[j] < remainingTime[cr] && remainingTime[j] > 0 || remainingTime[cr] == 0)) {
+                    cr = j;
+                }
+            }
+            ready.add(processes.get(cr).getProcessId());
+            remainingTime[cr]--;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java
new file mode 100644
index 000000000000..0cfe3d34f0ec
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java
@@ -0,0 +1,61 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.thealgorithms.devutils.entities.ProcessDetails;
+import java.util.ArrayList;
+import org.junit.jupiter.api.Test;
+
+class SRTFSchedulingTest {
+    ArrayList<ProcessDetails> processes;
+
+    public void initialization() {
+        processes = new ArrayList<>();
+        processes.add(new ProcessDetails("4", 0, 3));
+        processes.add(new ProcessDetails("3", 1, 8));
+        processes.add(new ProcessDetails("1", 2, 6));
+        processes.add(new ProcessDetails("5", 4, 4));
+        processes.add(new ProcessDetails("2", 5, 2));
+    }
+
+    @Test
+    public void Constructor() {
+        initialization();
+        SRTFScheduling s = new SRTFScheduling(processes);
+        assertEquals(3, s.processes.get(0).getBurstTime());
+        assertEquals(8, s.processes.get(1).getBurstTime());
+        assertEquals(6, s.processes.get(2).getBurstTime());
+        assertEquals(4, s.processes.get(3).getBurstTime());
+        assertEquals(2, s.processes.get(4).getBurstTime());
+    }
+
+    @Test
+    void evaluateScheduling() {
+        initialization();
+        SRTFScheduling s = new SRTFScheduling(processes);
+        s.evaluateScheduling();
+        assertEquals("4", s.ready.get(0));
+        assertEquals("4", s.ready.get(1));
+        assertEquals("4", s.ready.get(2));
+        assertEquals("1", s.ready.get(3));
+        assertEquals("5", s.ready.get(4));
+        assertEquals("2", s.ready.get(5));
+        assertEquals("2", s.ready.get(6));
+        assertEquals("5", s.ready.get(7));
+        assertEquals("5", s.ready.get(8));
+        assertEquals("5", s.ready.get(9));
+        assertEquals("1", s.ready.get(10));
+        assertEquals("1", s.ready.get(11));
+        assertEquals("1", s.ready.get(12));
+        assertEquals("1", s.ready.get(13));
+        assertEquals("1", s.ready.get(14));
+        assertEquals("3", s.ready.get(15));
+        assertEquals("3", s.ready.get(16));
+        assertEquals("3", s.ready.get(17));
+        assertEquals("3", s.ready.get(18));
+        assertEquals("3", s.ready.get(19));
+        assertEquals("3", s.ready.get(20));
+        assertEquals("3", s.ready.get(21));
+        assertEquals("3", s.ready.get(22));
+    }
+}

From 19b7a22ec94987f9d6a0df2079249c11deb9b337 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 10 Jan 2024 19:31:38 +0100
Subject: [PATCH 0090/1338] Remove unused imports from `BoyerMooreTest` (#5012)

---
 src/test/java/com/thealgorithms/others/BoyerMooreTest.java | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/test/java/com/thealgorithms/others/BoyerMooreTest.java b/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
index b1497f7bc525..b6620793d267 100644
--- a/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
+++ b/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
@@ -1,9 +1,7 @@
 package com.thealgorithms.others;
-import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.stream.Stream;
 import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;

From 8804cec9574badcdc1e690c6db1314a463c10458 Mon Sep 17 00:00:00 2001
From: Sarthak Chaudhary <86872379+SarthakChaudhary46@users.noreply.github.com>
Date: Sat, 13 Jan 2024 13:59:30 +0530
Subject: [PATCH 0091/1338] Feature/4638 array right rotation (#5014)

* Create ArrayRightRotationTest.java

* Create ArrayRightRotation.java

* The updated one

* The updated one

* Added the test cases

* Added new test cases!

* Update ArrayRightRotation.java

* Update ArrayRightRotationTest.java
---
 .../others/ArrayRightRotation.java            | 28 ++++++++++
 .../others/ArrayRightRotationTest.java        | 53 +++++++++++++++++++
 2 files changed, 81 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/others/ArrayRightRotation.java
 create mode 100644 src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java

diff --git a/src/test/java/com/thealgorithms/others/ArrayRightRotation.java b/src/test/java/com/thealgorithms/others/ArrayRightRotation.java
new file mode 100644
index 000000000000..a78ef81f32a4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/ArrayRightRotation.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.others;
+
+public class ArrayRightRotation {
+    public static int[] rotateRight(int[] arr, int k) {
+        if (arr == null || arr.length == 0 || k < 0) {
+            throw new IllegalArgumentException("Invalid input");
+        }
+
+        int n = arr.length;
+        k = k % n; // Handle cases where k is larger than the array length
+
+        reverseArray(arr, 0, n - 1);
+        reverseArray(arr, 0, k - 1);
+        reverseArray(arr, k, n - 1);
+
+        return arr;
+    }
+
+    private static void reverseArray(int[] arr, int start, int end) {
+        while (start < end) {
+            int temp = arr[start];
+            arr[start] = arr[end];
+            arr[end] = temp;
+            start++;
+            end--;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java b/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java
new file mode 100644
index 000000000000..f132d56dd9cd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+class ArrayRightRotationTest {
+
+    @Test
+    void testArrayRightRotation() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7};
+        int k = 3;
+        int[] expected = {5, 6, 7, 1, 2, 3, 4};
+        int[] result = ArrayRightRotation.rotateRight(arr, k);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void testArrayRightRotationWithZeroSteps() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7};
+        int k = 0;
+        int[] expected = {1, 2, 3, 4, 5, 6, 7};
+        int[] result = ArrayRightRotation.rotateRight(arr, k);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void testArrayRightRotationWithEqualSizeSteps() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7};
+        int k = arr.length;
+        int[] expected = {1, 2, 3, 4, 5, 6, 7};
+        int[] result = ArrayRightRotation.rotateRight(arr, k);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void testArrayRightRotationWithLowerSizeSteps() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7};
+        int k = 2;
+        int[] expected = {6, 7, 1, 2, 3, 4, 5};
+        int[] result = ArrayRightRotation.rotateRight(arr, k);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void testArrayRightRotationWithHigherSizeSteps() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7};
+        int k = 10;
+        int[] expected = {5, 6, 7, 1, 2, 3, 4};
+        int[] result = ArrayRightRotation.rotateRight(arr, k);
+        assertArrayEquals(expected, result);
+    }
+}

From 9426053f73d55efde9c3c601f9cf4f30a33ec673 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 13 Jan 2024 10:04:32 +0100
Subject: [PATCH 0092/1338] Remove unused import from `PowerOfTwoOrNotTest`
 (#5015)

style: remove unused import from `PowerOfTwoOrNotTest.java`
---
 src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java b/src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java
index df01d481ccd8..ac8d2be17d7c 100644
--- a/src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java
+++ b/src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java
@@ -3,7 +3,6 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.util.Map;
 import org.junit.jupiter.api.Test;
 
 public class PowerOfTwoOrNotTest {

From ac7152d757096d5a30e68b3864108e2843d0c2ed Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 13 Jan 2024 10:21:57 +0100
Subject: [PATCH 0093/1338] Remove unused imports from `PerfectSquareTest`
 (#5016)

style: remove unused imports from `PerfectSquareTest`
---
 src/test/java/com/thealgorithms/maths/PerfectSquareTest.java | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java b/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java
index 450ba972debe..08c96bc71f9b 100644
--- a/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java
+++ b/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java
@@ -1,8 +1,6 @@
 package com.thealgorithms.maths;
 
-import java.util.stream.Stream;
 import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 

From 3528399b2e385bffcfe0a2fff27d2a866d04a77a Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 13 Jan 2024 10:26:44 +0100
Subject: [PATCH 0094/1338] Remove unused import from `JobSequencing` (#5017)

style: remove unused import from `JobSequencing`
---
 .../java/com/thealgorithms/greedyalgorithms/JobSequencing.java   | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
index bf81e067bac1..4d2cf7c95a03 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
@@ -2,7 +2,6 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 
 // Problem Link: https://en.wikipedia.org/wiki/Job-shop_scheduling
 

From a216cb8a59ad04b3cadcc156e69dea41f3d1b465 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 13 Jan 2024 10:28:50 +0100
Subject: [PATCH 0095/1338] Remove unused import from `HashMapCuckooHashing`
 (#5018)

style: remove unused import from `HashMapCuckooHashing`
---
 .../datastructures/hashmap/hashing/HashMapCuckooHashing.java     | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
index 74b2527f925c..053751ebbc51 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
@@ -1,6 +1,5 @@
 package com.thealgorithms.datastructures.hashmap.hashing;
 
-import java.lang.Math;
 import java.util.Objects;
 
 /**

From 55f08cc0139579760964e786364e2239cc65a8d9 Mon Sep 17 00:00:00 2001
From: Bhishmadev Ghosh <111000117+bhishma620@users.noreply.github.com>
Date: Sat, 27 Jan 2024 00:00:26 +0530
Subject: [PATCH 0096/1338] Add tests `SumOfSubset` (#5021)

* Updated main and test

* removed

* style: reorder test cases

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../{Sum_Of_Subset.java => SumOfSubset.java}    | 13 +------------
 .../dynamicprogramming/SumOfSubsetTest.java     | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 12 deletions(-)
 rename src/main/java/com/thealgorithms/dynamicprogramming/{Sum_Of_Subset.java => SumOfSubset.java} (54%)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Sum_Of_Subset.java b/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
similarity index 54%
rename from src/main/java/com/thealgorithms/dynamicprogramming/Sum_Of_Subset.java
rename to src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
index 90c07889a57f..622f8b146d96 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Sum_Of_Subset.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
@@ -1,17 +1,6 @@
 package com.thealgorithms.dynamicprogramming;
 
-public class Sum_Of_Subset {
-
-    public static void main(String[] args) {
-        int[] arr = {7, 3, 2, 5, 8};
-        int Key = 14;
-
-        if (subsetSum(arr, arr.length - 1, Key)) {
-            System.out.print("Yes, that sum exists");
-        } else {
-            System.out.print("Nope, that number does not exist");
-        }
-    }
+public class SumOfSubset {
 
     public static boolean subsetSum(int[] arr, int num, int Key) {
         if (Key == 0) {
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java
new file mode 100644
index 000000000000..53c34937cbab
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java
@@ -0,0 +1,17 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class SumOfSubsetTest {
+
+    @Test
+    void basicCheck() {
+        assertEquals(false, SumOfSubset.subsetSum(new int[] {1, 2, 7, 10, 9}, 4, 14));
+        assertEquals(false, SumOfSubset.subsetSum(new int[] {2, 15, 1, 6, 7}, 4, 4));
+        assertEquals(true, SumOfSubset.subsetSum(new int[] {7, 3, 2, 5, 8}, 4, 14));
+        assertEquals(true, SumOfSubset.subsetSum(new int[] {4, 3, 2, 1}, 3, 5));
+        assertEquals(true, SumOfSubset.subsetSum(new int[] {1, 7, 2, 9, 10}, 4, 13));
+    }
+}

From b99aeef6743fc718c53c5aa29141d4f9e9f01460 Mon Sep 17 00:00:00 2001
From: Debasish Biswas <debasishbsws.dev@gmail.com>
Date: Mon, 29 Jan 2024 01:18:40 +0530
Subject: [PATCH 0097/1338] Remove debasishbsws from CODEOWNERS (#5033)

As I am not very active in this repository, I should step down from being a CodeOwner /cc @BamaCharanChhandogi @yanglbme
---
 .github/CODEOWNERS | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 0706d623599a..a84f13be1047 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1 +1 @@
-* @yanglbme @debasishbsws @vil02 @BamaCharanChhandogi
+* @yanglbme @vil02 @BamaCharanChhandogi

From 14b3f45f9f32df108de5d0eace624f23d6bbe1bf Mon Sep 17 00:00:00 2001
From: VedantK <145242784+555vedant@users.noreply.github.com>
Date: Thu, 1 Feb 2024 13:55:31 +0530
Subject: [PATCH 0098/1338] Add `ExchangeSort` (#5029)

* added ExchangeSort and its testcases

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/sorts/ExchangeSort.java | 47 +++++++++++++++++++
 .../thealgorithms/sorts/ExchangeSortTest.java |  8 ++++
 2 files changed, 55 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/ExchangeSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/ExchangeSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/ExchangeSort.java b/src/main/java/com/thealgorithms/sorts/ExchangeSort.java
new file mode 100644
index 000000000000..28303430950c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/ExchangeSort.java
@@ -0,0 +1,47 @@
+package com.thealgorithms.sorts;
+
+/**
+ * ExchangeSort is an implementation of the Exchange Sort algorithm.
+ *
+ * <p>
+ * Exchange sort works by comparing each element with all subsequent elements,
+ * swapping where needed, to ensure the correct placement of each element
+ * in the final sorted order. It iteratively performs this process for each
+ * element in the array. While it lacks the advantage of bubble sort in
+ * detecting sorted lists in one pass, it can be more efficient than bubble sort
+ * due to a constant factor (one less pass over the data to be sorted; half as
+ * many total comparisons) in worst-case scenarios.
+ * </p>
+ *
+ * <p>
+ * Reference: https://en.wikipedia.org/wiki/Sorting_algorithm#Exchange_sort
+ * </p>
+ *
+ * @author 555vedant (Vedant Kasar)
+ */
+class ExchangeSort implements SortAlgorithm {
+    /**
+     * Implementation of Exchange Sort Algorithm
+     *
+     * @param array the array to be sorted.
+     * @param <T>   the type of elements in the array.
+     * @return the sorted array.
+     */
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        for (int i = 0; i < array.length - 1; i++) {
+            for (int j = i + 1; j < array.length; j++) {
+                if (array[i].compareTo(array[j]) > 0) {
+                    swap(array, i, j);
+                }
+            }
+        }
+        return array;
+    }
+
+    private <T> void swap(T[] array, int i, int j) {
+        T temp = array[i];
+        array[i] = array[j];
+        array[j] = temp;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/ExchangeSortTest.java b/src/test/java/com/thealgorithms/sorts/ExchangeSortTest.java
new file mode 100644
index 000000000000..6c4271fa9e19
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/ExchangeSortTest.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.sorts;
+
+public class ExchangeSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new ExchangeSort();
+    }
+}

From 55cc562d64a0e7caa622d18a67f51cf79970f48e Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 11 Feb 2024 22:21:08 +0100
Subject: [PATCH 0099/1338] chore: update `actions/checkout` to `v4` (#5036)

---
 .github/workflows/codeql.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 482c8bc60527..cea50a26c19a 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -24,7 +24,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Set up JDK 17
         uses: actions/setup-java@v3

From 47a9b1b647d890d3cce50cd21774f5c78c350782 Mon Sep 17 00:00:00 2001
From: straf10 <115450409+straf10@users.noreply.github.com>
Date: Mon, 12 Feb 2024 21:48:07 +0200
Subject: [PATCH 0100/1338] Add `WelshPowell` (Graph Colouring) (#5034)

* Welsh Powell Algorithm + Test


---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../datastructures/graphs/WelshPowell.java    | 113 ++++++++++++++++
 .../graphs/WelshPowellTest.java               | 124 ++++++++++++++++++
 2 files changed, 237 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java b/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
new file mode 100644
index 000000000000..3b823f02388d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
@@ -0,0 +1,113 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.stream.IntStream;
+
+/*
+ *  The Welsh-Powell algorithm is a graph coloring algorithm
+ *  used for coloring a graph with the minimum number of colors.
+ *  https://en.wikipedia.org/wiki/Graph_coloring
+ */
+
+public final class WelshPowell {
+    private static final int BLANK_COLOR = -1; // Representing uncolored state
+
+    private WelshPowell() {
+    }
+
+    static class Graph {
+        private HashSet<Integer>[] adjacencyLists;
+
+        private Graph(int vertices) {
+            if (vertices < 0) {
+                throw new IllegalArgumentException("Number of vertices cannot be negative");
+            }
+
+            adjacencyLists = new HashSet[vertices];
+            Arrays.setAll(adjacencyLists, i -> new HashSet<>());
+        }
+
+        private void addEdge(int nodeA, int nodeB) {
+            validateVertex(nodeA);
+            validateVertex(nodeB);
+            if (nodeA == nodeB) {
+                throw new IllegalArgumentException("Self-loops are not allowed");
+            }
+            adjacencyLists[nodeA].add(nodeB);
+            adjacencyLists[nodeB].add(nodeA);
+        }
+
+        private void validateVertex(int vertex) {
+            if (vertex < 0 || vertex >= getNumVertices()) {
+                throw new IllegalArgumentException("Vertex " + vertex + " is out of bounds");
+            }
+        }
+
+        HashSet<Integer> getAdjacencyList(int vertex) {
+            return adjacencyLists[vertex];
+        }
+
+        int getNumVertices() {
+            return adjacencyLists.length;
+        }
+    }
+
+    public static Graph makeGraph(int numberOfVertices, int[][] listOfEdges) {
+        Graph graph = new Graph(numberOfVertices);
+        for (int[] edge : listOfEdges) {
+            if (edge.length != 2) {
+                throw new IllegalArgumentException("Edge array must have exactly two elements");
+            }
+            graph.addEdge(edge[0], edge[1]);
+        }
+        return graph;
+    }
+
+    public static int[] findColoring(Graph graph) {
+        int[] colors = initializeColors(graph.getNumVertices());
+        Integer[] sortedVertices = getSortedNodes(graph);
+        for (int vertex : sortedVertices) {
+            if (isBlank(colors[vertex])) {
+                boolean[] usedColors = computeUsedColors(graph, vertex, colors);
+                final var newColor = firstUnusedColor(usedColors);
+                colors[vertex] = newColor;
+                Arrays.stream(sortedVertices).forEach(otherVertex -> {
+                    if (isBlank(colors[otherVertex]) && !isAdjacentToColored(graph, otherVertex, colors)) {
+                        colors[otherVertex] = newColor;
+                    }
+                });
+            }
+        }
+        return colors;
+    }
+
+    private static boolean isBlank(int color) {
+        return color == BLANK_COLOR;
+    }
+
+    private static boolean isAdjacentToColored(Graph graph, int vertex, int[] colors) {
+        return graph.getAdjacencyList(vertex).stream().anyMatch(otherVertex -> !isBlank(colors[otherVertex]));
+    }
+
+    private static int[] initializeColors(int numberOfVertices) {
+        int[] colors = new int[numberOfVertices];
+        Arrays.fill(colors, BLANK_COLOR);
+        return colors;
+    }
+
+    private static Integer[] getSortedNodes(final Graph graph) {
+        return IntStream.range(0, graph.getNumVertices()).boxed().sorted(Comparator.comparingInt(v -> - graph.getAdjacencyList(v).size())).toArray(Integer[] ::new);
+    }
+
+    private static boolean[] computeUsedColors(final Graph graph, final int vertex, final int[] colors) {
+        boolean[] usedColors = new boolean[graph.getNumVertices()];
+        graph.getAdjacencyList(vertex).stream().map(neighbor -> colors[neighbor]).filter(color -> !isBlank(color)).forEach(color -> usedColors[color] = true);
+        return usedColors;
+    }
+
+    private static int firstUnusedColor(boolean[] usedColors) {
+        return IntStream.range(0, usedColors.length).filter(color -> !usedColors[color]).findFirst().getAsInt();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java
new file mode 100644
index 000000000000..b37657db5c05
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java
@@ -0,0 +1,124 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.thealgorithms.datastructures.graphs.WelshPowell.Graph;
+import java.util.Arrays;
+import org.junit.jupiter.api.Test;
+
+class WelshPowellTest {
+
+    @Test
+    void testSimpleGraph() {
+        final var graph = WelshPowell.makeGraph(4, new int[][] {{0, 1}, {1, 2}, {2, 3}});
+        int[] colors = WelshPowell.findColoring(graph);
+        assertTrue(isColoringValid(graph, colors));
+        assertEquals(2, countDistinctColors(colors));
+    }
+
+    @Test
+    void testDisconnectedGraph() {
+        final var graph = WelshPowell.makeGraph(3, new int[][] {}); // No edges
+        int[] colors = WelshPowell.findColoring(graph);
+        assertTrue(isColoringValid(graph, colors));
+        assertEquals(1, countDistinctColors(colors));
+    }
+
+    @Test
+    void testCompleteGraph() {
+        final var graph = WelshPowell.makeGraph(3, new int[][] {{0, 1}, {1, 2}, {2, 0}});
+        int[] colors = WelshPowell.findColoring(graph);
+        assertTrue(isColoringValid(graph, colors));
+        assertEquals(3, countDistinctColors(colors));
+    }
+
+    // The following test originates from the following website : https://www.geeksforgeeks.org/welsh-powell-graph-colouring-algorithm/
+    @Test
+    void testComplexGraph() {
+        int[][] edges = {
+            {0, 7}, // A-H
+            {0, 1}, // A-B
+            {1, 3}, // B-D
+            {2, 3}, // C-D
+            {3, 8}, // D-I
+            {3, 10}, // D-K
+            {4, 10}, // E-K
+            {4, 5}, // E-F
+            {5, 6}, // F-G
+            {6, 10}, // G-K
+            {6, 7}, // G-H
+            {7, 8}, // H-I
+            {7, 9}, // H-J
+            {7, 10}, // H-K
+            {8, 9}, // I-J
+            {9, 10}, // J-K
+        };
+
+        final var graph = WelshPowell.makeGraph(11, edges); // 11 vertices from A (0) to K (10)
+        int[] colors = WelshPowell.findColoring(graph);
+
+        assertTrue(isColoringValid(graph, colors), "The coloring should be valid with no adjacent vertices sharing the same color.");
+        assertEquals(3, countDistinctColors(colors), "The chromatic number of the graph should be 3.");
+    }
+
+    @Test
+    void testNegativeVertices() {
+        assertThrows(IllegalArgumentException.class, () -> { WelshPowell.makeGraph(-1, new int[][] {}); }, "Number of vertices cannot be negative");
+    }
+
+    @Test
+    void testSelfLoop() {
+        assertThrows(IllegalArgumentException.class, () -> { WelshPowell.makeGraph(3, new int[][] {{0, 0}}); }, "Self-loops are not allowed");
+    }
+
+    @Test
+    void testInvalidVertex() {
+        assertThrows(IllegalArgumentException.class, () -> { WelshPowell.makeGraph(3, new int[][] {{0, 3}}); }, "Vertex out of bounds");
+        assertThrows(IllegalArgumentException.class, () -> { WelshPowell.makeGraph(3, new int[][] {{0, -1}}); }, "Vertex out of bounds");
+    }
+
+    @Test
+    void testInvalidEdgeArray() {
+        assertThrows(IllegalArgumentException.class, () -> { WelshPowell.makeGraph(3, new int[][] {{0}}); }, "Edge array must have exactly two elements");
+    }
+
+    @Test
+    void testWithPreColoredVertex() {
+        // Create a linear graph with 4 vertices and edges connecting them in sequence
+        final var graph = WelshPowell.makeGraph(4, new int[][] {{0, 1}, {1, 2}, {2, 3}});
+
+        // Apply the Welsh-Powell coloring algorithm to the graph
+        int[] colors = WelshPowell.findColoring(graph);
+
+        // Validate that the coloring is correct (no two adjacent vertices have the same color)
+        assertTrue(isColoringValid(graph, colors));
+
+        // Check if the algorithm has used at least 2 colors (expected for a linear graph)
+        assertTrue(countDistinctColors(colors) >= 2);
+
+        // Verify that all vertices have been assigned a color
+        for (int color : colors) {
+            assertTrue(color >= 0);
+        }
+    }
+
+    private boolean isColoringValid(Graph graph, int[] colors) {
+        if (Arrays.stream(colors).anyMatch(n -> n < 0)) {
+            return false;
+        }
+        for (int i = 0; i < graph.getNumVertices(); i++) {
+            for (int neighbor : graph.getAdjacencyList(i)) {
+                if (i != neighbor && colors[i] == colors[neighbor]) {
+                    return false; // Adjacent vertices have the same color
+                }
+            }
+        }
+        return true; // No adjacent vertices share the same color
+    }
+
+    private int countDistinctColors(int[] colors) {
+        return (int) Arrays.stream(colors).distinct().count();
+    }
+}

From ab371843aca53ab802e21427d28de5a65577a694 Mon Sep 17 00:00:00 2001
From: SOZEL <80200848+TruongNhanNguyen@users.noreply.github.com>
Date: Wed, 13 Mar 2024 01:49:58 +0700
Subject: [PATCH 0101/1338] Close `Scanner` to avoid resource leak (#5077)

---
 .../thealgorithms/ciphers/ProductCipher.java  | 107 ++++++++---------
 .../datastructures/graphs/BellmanFord.java    | 109 +++++++++---------
 .../datastructures/stacks/ReverseStack.java   |  40 +++----
 .../maths/NonRepeatingElement.java            | 103 +++++++++--------
 .../others/InsertDeleteInArray.java           |  73 ++++++------
 .../searches/RecursiveBinarySearch.java       |  36 +++---
 6 files changed, 243 insertions(+), 225 deletions(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/ProductCipher.java b/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
index c5ce8a9b157c..5b1d46fe9a9a 100644
--- a/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
@@ -5,67 +5,68 @@
 class ProductCipher {
 
     public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        System.out.println("Enter the input to be encrypted: ");
-        String substitutionInput = sc.nextLine();
-        System.out.println(" ");
-        System.out.println("Enter a number: ");
-        int n = sc.nextInt();
+        try (Scanner sc = new Scanner(System.in)) {
+            System.out.println("Enter the input to be encrypted: ");
+            String substitutionInput = sc.nextLine();
+            System.out.println(" ");
+            System.out.println("Enter a number: ");
+            int n = sc.nextInt();
 
-        // Substitution encryption
-        StringBuffer substitutionOutput = new StringBuffer();
-        for (int i = 0; i < substitutionInput.length(); i++) {
-            char c = substitutionInput.charAt(i);
-            substitutionOutput.append((char) (c + 5));
-        }
-        System.out.println(" ");
-        System.out.println("Substituted text: ");
-        System.out.println(substitutionOutput);
+            // Substitution encryption
+            StringBuffer substitutionOutput = new StringBuffer();
+            for (int i = 0; i < substitutionInput.length(); i++) {
+                char c = substitutionInput.charAt(i);
+                substitutionOutput.append((char) (c + 5));
+            }
+            System.out.println(" ");
+            System.out.println("Substituted text: ");
+            System.out.println(substitutionOutput);
 
-        // Transposition encryption
-        String transpositionInput = substitutionOutput.toString();
-        int modulus;
-        if ((modulus = transpositionInput.length() % n) != 0) {
-            modulus = n - modulus;
+            // Transposition encryption
+            String transpositionInput = substitutionOutput.toString();
+            int modulus;
+            if ((modulus = transpositionInput.length() % n) != 0) {
+                modulus = n - modulus;
 
-            for (; modulus != 0; modulus--) {
-                transpositionInput += "/";
+                for (; modulus != 0; modulus--) {
+                    transpositionInput += "/";
+                }
             }
-        }
-        StringBuffer transpositionOutput = new StringBuffer();
-        System.out.println(" ");
-        System.out.println("Transposition Matrix: ");
-        for (int i = 0; i < n; i++) {
-            for (int j = 0; j < transpositionInput.length() / n; j++) {
-                char c = transpositionInput.charAt(i + (j * n));
-                System.out.print(c);
-                transpositionOutput.append(c);
+            StringBuffer transpositionOutput = new StringBuffer();
+            System.out.println(" ");
+            System.out.println("Transposition Matrix: ");
+            for (int i = 0; i < n; i++) {
+                for (int j = 0; j < transpositionInput.length() / n; j++) {
+                    char c = transpositionInput.charAt(i + (j * n));
+                    System.out.print(c);
+                    transpositionOutput.append(c);
+                }
+                System.out.println();
             }
-            System.out.println();
-        }
-        System.out.println(" ");
-        System.out.println("Final encrypted text: ");
-        System.out.println(transpositionOutput);
+            System.out.println(" ");
+            System.out.println("Final encrypted text: ");
+            System.out.println(transpositionOutput);
 
-        // Transposition decryption
-        n = transpositionOutput.length() / n;
-        StringBuffer transpositionPlaintext = new StringBuffer();
-        for (int i = 0; i < n; i++) {
-            for (int j = 0; j < transpositionOutput.length() / n; j++) {
-                char c = transpositionOutput.charAt(i + (j * n));
-                transpositionPlaintext.append(c);
+            // Transposition decryption
+            n = transpositionOutput.length() / n;
+            StringBuffer transpositionPlaintext = new StringBuffer();
+            for (int i = 0; i < n; i++) {
+                for (int j = 0; j < transpositionOutput.length() / n; j++) {
+                    char c = transpositionOutput.charAt(i + (j * n));
+                    transpositionPlaintext.append(c);
+                }
             }
-        }
 
-        // Substitution decryption
-        StringBuffer plaintext = new StringBuffer();
-        for (int i = 0; i < transpositionPlaintext.length(); i++) {
-            char c = transpositionPlaintext.charAt(i);
-            plaintext.append((char) (c - 5));
-        }
+            // Substitution decryption
+            StringBuffer plaintext = new StringBuffer();
+            for (int i = 0; i < transpositionPlaintext.length(); i++) {
+                char c = transpositionPlaintext.charAt(i);
+                plaintext.append((char) (c - 5));
+            }
 
-        System.out.println("Plaintext: ");
-        System.out.println(plaintext);
-        sc.close();
+            System.out.println("Plaintext: ");
+            System.out.println(plaintext);
+            sc.close();
+        }
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
index 8229c1fa947d..9f5022b44465 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
@@ -2,9 +2,13 @@
 
 import java.util.*;
 
-class BellmanFord /*Implementation of Bellman ford to detect negative cycles. Graph accepts inputs
-in form of edges which have start vertex, end vertex and weights. Vertices should be labelled with a
-number between 0 and total number of vertices-1,both inclusive*/
+class BellmanFord /*
+                   * Implementation of Bellman ford to detect negative cycles. Graph accepts
+                   * inputs
+                   * in form of edges which have start vertex, end vertex and weights. Vertices
+                   * should be labelled with a
+                   * number between 0 and total number of vertices-1,both inclusive
+                   */
 {
 
     int vertex, edge;
@@ -36,7 +40,7 @@ public Edge(int a, int b, int c) {
 
     /**
      * @param p[] Parent array which shows updates in edges
-     * @param i Current vertex under consideration
+     * @param i   Current vertex under consideration
      */
     void printPath(int[] p, int i) {
         if (p[i] == -1) { // Found the path back to parent
@@ -52,64 +56,65 @@ public static void main(String[] args) {
     }
 
     public void go() { // shows distance to all vertices // Interactive run for understanding the
-                       // class first time. Assumes source vertex is 0 and
-        Scanner sc = new Scanner(System.in); // Grab scanner object for user input
-        int i, v, e, u, ve, w, j, neg = 0;
-        System.out.println("Enter no. of vertices and edges please");
-        v = sc.nextInt();
-        e = sc.nextInt();
-        Edge[] arr = new Edge[e]; // Array of edges
-        System.out.println("Input edges");
-        for (i = 0; i < e; i++) {
-            u = sc.nextInt();
-            ve = sc.nextInt();
-            w = sc.nextInt();
-            arr[i] = new Edge(u, ve, w);
-        }
-        int[] dist = new int[v]; // Distance array for holding the finalized shortest path distance
-                                 // between source
-        // and all vertices
-        int[] p = new int[v]; // Parent array for holding the paths
-        for (i = 0; i < v; i++) {
-            dist[i] = Integer.MAX_VALUE; // Initializing distance values
-        }
-        dist[0] = 0;
-        p[0] = -1;
-        for (i = 0; i < v - 1; i++) {
+        try ( // class first time. Assumes source vertex is 0 and
+            Scanner sc = new Scanner(System.in)) {
+            int i, v, e, u, ve, w, j, neg = 0;
+            System.out.println("Enter no. of vertices and edges please");
+            v = sc.nextInt();
+            e = sc.nextInt();
+            Edge[] arr = new Edge[e]; // Array of edges
+            System.out.println("Input edges");
+            for (i = 0; i < e; i++) {
+                u = sc.nextInt();
+                ve = sc.nextInt();
+                w = sc.nextInt();
+                arr[i] = new Edge(u, ve, w);
+            }
+            int[] dist = new int[v]; // Distance array for holding the finalized shortest path distance
+                                     // between source
+            // and all vertices
+            int[] p = new int[v]; // Parent array for holding the paths
+            for (i = 0; i < v; i++) {
+                dist[i] = Integer.MAX_VALUE; // Initializing distance values
+            }
+            dist[0] = 0;
+            p[0] = -1;
+            for (i = 0; i < v - 1; i++) {
+                for (j = 0; j < e; j++) {
+                    if (dist[arr[j].u] != Integer.MAX_VALUE && dist[arr[j].v] > dist[arr[j].u] + arr[j].w) {
+                        dist[arr[j].v] = dist[arr[j].u] + arr[j].w; // Update
+                        p[arr[j].v] = arr[j].u;
+                    }
+                }
+            }
+            // Final cycle for negative checking
             for (j = 0; j < e; j++) {
                 if (dist[arr[j].u] != Integer.MAX_VALUE && dist[arr[j].v] > dist[arr[j].u] + arr[j].w) {
-                    dist[arr[j].v] = dist[arr[j].u] + arr[j].w; // Update
-                    p[arr[j].v] = arr[j].u;
+                    neg = 1;
+                    System.out.println("Negative cycle");
+                    break;
                 }
             }
-        }
-        // Final cycle for negative checking
-        for (j = 0; j < e; j++) {
-            if (dist[arr[j].u] != Integer.MAX_VALUE && dist[arr[j].v] > dist[arr[j].u] + arr[j].w) {
-                neg = 1;
-                System.out.println("Negative cycle");
-                break;
-            }
-        }
-        if (neg == 0) { // Go ahead and show results of computation
-            System.out.println("Distances are: ");
-            for (i = 0; i < v; i++) {
-                System.out.println(i + " " + dist[i]);
-            }
-            System.out.println("Path followed:");
-            for (i = 0; i < v; i++) {
-                System.out.print("0 ");
-                printPath(p, i);
-                System.out.println();
+            if (neg == 0) { // Go ahead and show results of computation
+                System.out.println("Distances are: ");
+                for (i = 0; i < v; i++) {
+                    System.out.println(i + " " + dist[i]);
+                }
+                System.out.println("Path followed:");
+                for (i = 0; i < v; i++) {
+                    System.out.print("0 ");
+                    printPath(p, i);
+                    System.out.println();
+                }
             }
+            sc.close();
         }
-        sc.close();
     }
 
     /**
      * @param source Starting vertex
-     * @param end Ending vertex
-     * @param Edge Array of edges
+     * @param end    Ending vertex
+     * @param Edge   Array of edges
      */
     public void show(int source, int end,
         Edge[] arr) { // be created by using addEdge() method and passed by calling getEdgeArray()
diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java b/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
index f269d08b5678..c9d2ea05778b 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
@@ -11,21 +11,22 @@
 public class ReverseStack {
 
     public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        System.out.println("Enter the number of elements you wish to insert in the stack");
-        int n = sc.nextInt();
-        int i;
-        Stack<Integer> stack = new Stack<Integer>();
-        System.out.println("Enter the stack elements");
-        for (i = 0; i < n; i++) {
-            stack.push(sc.nextInt());
-        }
-        sc.close();
-        reverseStack(stack);
-        System.out.println("The reversed stack is:");
-        while (!stack.isEmpty()) {
-            System.out.print(stack.peek() + ",");
-            stack.pop();
+        try (Scanner sc = new Scanner(System.in)) {
+            System.out.println("Enter the number of elements you wish to insert in the stack");
+            int n = sc.nextInt();
+            int i;
+            Stack<Integer> stack = new Stack<Integer>();
+            System.out.println("Enter the stack elements");
+            for (i = 0; i < n; i++) {
+                stack.push(sc.nextInt());
+            }
+            sc.close();
+            reverseStack(stack);
+            System.out.println("The reversed stack is:");
+            while (!stack.isEmpty()) {
+                System.out.print(stack.peek() + ",");
+                stack.pop();
+            }
         }
     }
 
@@ -48,16 +49,15 @@ private static void reverseStack(Stack<Integer> stack) {
 
     private static void insertAtBottom(Stack<Integer> stack, int element) {
         if (stack.isEmpty()) {
-            // When stack is empty, insert the element so it will be present at the bottom of the
-            // stack
+            // When stack is empty, insert the element so it will be present at
+            // the bottom of the stack
             stack.push(element);
             return;
         }
 
         int ele = stack.peek();
-        /*Keep popping elements till stack becomes empty. Push the elements once the topmost element
-           has moved to the bottom of the stack.
-         */
+        // Keep popping elements till stack becomes empty. Push the elements
+        // once the topmost element has moved to the bottom of the stack.
         stack.pop();
         insertAtBottom(stack, element);
 
diff --git a/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java b/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
index 86dce42f1564..01fdd5a6a5a5 100644
--- a/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
+++ b/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
@@ -10,61 +10,70 @@
 public class NonRepeatingElement {
 
     public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        int i, res = 0;
-        System.out.println("Enter the number of elements in the array");
-        int n = sc.nextInt();
-        if ((n & 1) == 1) {
-            // Not allowing odd number of elements as we are expecting 2 non repeating numbers
-            System.out.println("Array should contain even number of elements");
-            return;
-        }
-        int[] arr = new int[n];
+        try (Scanner sc = new Scanner(System.in)) {
+            int i, res = 0;
+            System.out.println("Enter the number of elements in the array");
+            int n = sc.nextInt();
+            if ((n & 1) == 1) {
+                // Not allowing odd number of elements as we are expecting 2 non repeating
+                // numbers
+                System.out.println("Array should contain even number of elements");
+                return;
+            }
+            int[] arr = new int[n];
 
-        System.out.println("Enter " + n + " elements in the array. NOTE: Only 2 elements should not repeat");
-        for (i = 0; i < n; i++) {
-            arr[i] = sc.nextInt();
-        }
+            System.out.println("Enter " + n + " elements in the array. NOTE: Only 2 elements should not repeat");
+            for (i = 0; i < n; i++) {
+                arr[i] = sc.nextInt();
+            }
 
-        try {
-            sc.close();
-        } catch (Exception e) {
-            System.out.println("Unable to close scanner" + e);
-        }
+            try {
+                sc.close();
+            } catch (Exception e) {
+                System.out.println("Unable to close scanner" + e);
+            }
 
-        // Find XOR of the 2 non repeating elements
-        for (i = 0; i < n; i++) {
-            res ^= arr[i];
-        }
+            // Find XOR of the 2 non repeating elements
+            for (i = 0; i < n; i++) {
+                res ^= arr[i];
+            }
 
-        // Finding the rightmost set bit
-        res = res & (-res);
-        int num1 = 0, num2 = 0;
+            // Finding the rightmost set bit
+            res = res & (-res);
+            int num1 = 0, num2 = 0;
 
-        for (i = 0; i < n; i++) {
-            if ((res & arr[i]) > 0) { // Case 1 explained below
-                num1 ^= arr[i];
-            } else {
-                num2 ^= arr[i]; // Case 2 explained below
+            for (i = 0; i < n; i++) {
+                if ((res & arr[i]) > 0) { // Case 1 explained below
+                    num1 ^= arr[i];
+                } else {
+                    num2 ^= arr[i]; // Case 2 explained below
+                }
             }
-        }
 
-        System.out.println("The two non repeating elements are " + num1 + " and " + num2);
-        sc.close();
+            System.out.println("The two non repeating elements are " + num1 + " and " + num2);
+            sc.close();
+        }
     }
     /*
-  Explanation of the code:
-  let us assume we have an array [1,2,1,2,3,4]
-  Property of XOR: num ^ num = 0.
-  If we XOR all the elemnets of the array we will be left with 3 ^ 4 as 1 ^ 1 and 2 ^ 2 would give
-  0. Our task is to find num1 and num2 from the result of 3 ^ 4 = 7. We need to find two's
-  complement of 7 and find the rightmost set bit. i.e. (num & (-num)) Two's complement of 7 is 001
-  and hence res = 1. There can be 2 options when we Bitise AND this res with all the elements in our
-  array
-  1. Result will come non zero number
-  2. Result will be 0.
-  In the first case we will XOR our element with the first number (which is initially 0)
-  In the second case we will XOR our element with the second number(which is initially 0)
-  This is how we will get non repeating elements with the help of bitwise operators.
+     * Explanation of the code:
+     * let us assume we have an array [1,2,1,2,3,4]
+     * Property of XOR: num ^ num = 0.
+     * If we XOR all the elemnets of the array we will be left with 3 ^ 4 as 1 ^ 1
+     * and 2 ^ 2 would give
+     * 0. Our task is to find num1 and num2 from the result of 3 ^ 4 = 7. We need to
+     * find two's
+     * complement of 7 and find the rightmost set bit. i.e. (num & (-num)) Two's
+     * complement of 7 is 001
+     * and hence res = 1. There can be 2 options when we Bitise AND this res with
+     * all the elements in our
+     * array
+     * 1. Result will come non zero number
+     * 2. Result will be 0.
+     * In the first case we will XOR our element with the first number (which is
+     * initially 0)
+     * In the second case we will XOR our element with the second number(which is
+     * initially 0)
+     * This is how we will get non repeating elements with the help of bitwise
+     * operators.
      */
 }
diff --git a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
index c90cfea1fcb1..201c0ad2dd80 100644
--- a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
+++ b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
@@ -5,46 +5,47 @@
 public class InsertDeleteInArray {
 
     public static void main(String[] args) {
-        Scanner s = new Scanner(System.in); // Input statement
-        System.out.println("Enter the size of the array");
-        int size = s.nextInt();
-        int[] a = new int[size];
-        int i;
+        try (Scanner s = new Scanner(System.in)) {
+            System.out.println("Enter the size of the array");
+            int size = s.nextInt();
+            int[] a = new int[size];
+            int i;
 
-        // To enter the initial elements
-        for (i = 0; i < size; i++) {
-            System.out.println("Enter the element");
-            a[i] = s.nextInt();
-        }
+            // To enter the initial elements
+            for (i = 0; i < size; i++) {
+                System.out.println("Enter the element");
+                a[i] = s.nextInt();
+            }
 
-        // To insert a new element(we are creating a new array)
-        System.out.println("Enter the index at which the element should be inserted");
-        int insert_pos = s.nextInt();
-        System.out.println("Enter the element to be inserted");
-        int ins = s.nextInt();
-        int size2 = size + 1;
-        int[] b = new int[size2];
-        for (i = 0; i < size2; i++) {
-            if (i <= insert_pos) {
-                b[i] = a[i];
-            } else {
-                b[i] = a[i - 1];
+            // To insert a new element(we are creating a new array)
+            System.out.println("Enter the index at which the element should be inserted");
+            int insert_pos = s.nextInt();
+            System.out.println("Enter the element to be inserted");
+            int ins = s.nextInt();
+            int size2 = size + 1;
+            int[] b = new int[size2];
+            for (i = 0; i < size2; i++) {
+                if (i <= insert_pos) {
+                    b[i] = a[i];
+                } else {
+                    b[i] = a[i - 1];
+                }
+            }
+            b[insert_pos] = ins;
+            for (i = 0; i < size2; i++) {
+                System.out.println(b[i]);
             }
-        }
-        b[insert_pos] = ins;
-        for (i = 0; i < size2; i++) {
-            System.out.println(b[i]);
-        }
 
-        // To delete an element given the index
-        System.out.println("Enter the index at which element is to be deleted");
-        int del_pos = s.nextInt();
-        for (i = del_pos; i < size2 - 1; i++) {
-            b[i] = b[i + 1];
-        }
-        for (i = 0; i < size2 - 1; i++) {
-            System.out.println(b[i]);
+            // To delete an element given the index
+            System.out.println("Enter the index at which element is to be deleted");
+            int del_pos = s.nextInt();
+            for (i = del_pos; i < size2 - 1; i++) {
+                b[i] = b[i + 1];
+            }
+            for (i = 0; i < size2 - 1; i++) {
+                System.out.println(b[i]);
+            }
+            s.close();
         }
-        s.close();
     }
 }
diff --git a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
index 0a84aa1d64ce..8860f3380e31 100644
--- a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
@@ -3,6 +3,7 @@
 // File Name should be RecursiveBinarySearch.java
 // Explanation:- https://www.tutorialspoint.com/java-program-for-binary-search-recursive
 package com.thealgorithms.searches;
+
 import java.util.*;
 
 // Create a SearchAlgorithm class with a generic type
@@ -47,28 +48,29 @@ public int binsear(T[] arr, int left, int right, T target) {
     }
 
     public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        // User inputs
-        System.out.print("Enter the number of elements in the array: ");
-        int n = sc.nextInt();
+        try (Scanner sc = new Scanner(System.in)) {
+            // User inputs
+            System.out.print("Enter the number of elements in the array: ");
+            int n = sc.nextInt();
 
-        Integer[] a = new Integer[n]; // You can change the array type as needed
+            Integer[] a = new Integer[n]; // You can change the array type as needed
 
-        System.out.println("Enter the elements in sorted order:");
+            System.out.println("Enter the elements in sorted order:");
 
-        for (int i = 0; i < n; i++) {
-            a[i] = sc.nextInt();
-        }
+            for (int i = 0; i < n; i++) {
+                a[i] = sc.nextInt();
+            }
 
-        System.out.print("Enter the target element to search for: ");
-        int t = sc.nextInt();
+            System.out.print("Enter the target element to search for: ");
+            int t = sc.nextInt();
 
-        RecursiveBinarySearch<Integer> searcher = new RecursiveBinarySearch<>();
-        int res = searcher.find(a, t);
+            RecursiveBinarySearch<Integer> searcher = new RecursiveBinarySearch<>();
+            int res = searcher.find(a, t);
 
-        if (res == -1)
-            System.out.println("Element not found in the array.");
-        else
-            System.out.println("Element found at index " + res);
+            if (res == -1)
+                System.out.println("Element not found in the array.");
+            else
+                System.out.println("Element found at index " + res);
+        }
     }
 }

From 192427a5d288b3b7d4eca28056ded28cac513b61 Mon Sep 17 00:00:00 2001
From: SOZEL <80200848+TruongNhanNguyen@users.noreply.github.com>
Date: Sat, 16 Mar 2024 01:03:27 +0700
Subject: [PATCH 0102/1338] Parameterize references to generic types.  (#5078)

* chore: remove unused imports

* fix: parameterize references to generic types


---------

Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 src/main/java/com/thealgorithms/backtracking/MColoring.java   | 1 -
 .../datastructures/dynamicarray/DynamicArray.java             | 2 +-
 .../thealgorithms/datastructures/lists/CircleLinkedList.java  | 4 ++--
 .../thealgorithms/datastructures/lists/CursorLinkedList.java  | 2 +-
 src/main/java/com/thealgorithms/misc/ThreeSumProblem.java     | 4 ++--
 src/main/java/com/thealgorithms/searches/UnionFind.java       | 2 +-
 src/main/java/com/thealgorithms/strings/WordLadder.java       | 4 ++--
 7 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/MColoring.java b/src/main/java/com/thealgorithms/backtracking/MColoring.java
index c9bc02008058..93b17941566a 100644
--- a/src/main/java/com/thealgorithms/backtracking/MColoring.java
+++ b/src/main/java/com/thealgorithms/backtracking/MColoring.java
@@ -1,6 +1,5 @@
 package com.thealgorithms.backtracking;
 
-import java.io.*;
 import java.util.*;
 
 /**
diff --git a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
index fb7783575e57..f6f0276e0c35 100644
--- a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
@@ -145,7 +145,7 @@ public String toString() {
      * @return Iterator a Dynamic Array Iterator
      */
     @Override
-    public Iterator iterator() {
+    public Iterator<E> iterator() {
         return new DynamicArrayIterator();
     }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
index 5d9f0b3a1d28..c42b10455d14 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
@@ -53,7 +53,7 @@ public void append(E value) {
 
     // utility function for traversing the list
     public String toString() {
-        Node p = head.next;
+        Node<E> p = head.next;
         String s = "[ ";
         while (p != head) {
             s += p.value;
@@ -91,7 +91,7 @@ public E remove(int pos) {
     }
 
     public static void main(String[] args) {
-        CircleLinkedList cl = new CircleLinkedList<String>();
+        CircleLinkedList<Integer> cl = new CircleLinkedList<>();
         cl.append(12);
         System.out.println(cl);
         cl.append(23);
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
index cefc47c27169..22399bd6a459 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
@@ -134,7 +134,7 @@ public void remove(T element) {
     }
 
     private void free(int index) {
-        Node os_node = cursorSpace[os];
+        Node<T> os_node = cursorSpace[os];
         int os_next = os_node.next;
         cursorSpace[os].next = index;
         cursorSpace[index].element = null;
diff --git a/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java b/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
index 1b72996d022b..a232ad986970 100644
--- a/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
+++ b/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
@@ -75,7 +75,7 @@ public List<List<Integer>> TwoPointer(int[] nums, int target) {
 
     public List<List<Integer>> Hashmap(int[] nums, int target) {
         Arrays.sort(nums);
-        Set<List<Integer>> ts = new HashSet();
+        Set<List<Integer>> ts = new HashSet<>();
         HashMap<Integer, Integer> hm = new HashMap<>();
 
         for (int i = 0; i < nums.length; i++) {
@@ -94,6 +94,6 @@ public List<List<Integer>> Hashmap(int[] nums, int target) {
                 }
             }
         }
-        return new ArrayList(ts);
+        return new ArrayList<>(ts);
     }
 }
diff --git a/src/main/java/com/thealgorithms/searches/UnionFind.java b/src/main/java/com/thealgorithms/searches/UnionFind.java
index d32e4fd3ec1f..4dfece0e6381 100644
--- a/src/main/java/com/thealgorithms/searches/UnionFind.java
+++ b/src/main/java/com/thealgorithms/searches/UnionFind.java
@@ -45,7 +45,7 @@ public void union(int x, int y) {
     }
 
     public int count() {
-        List parents = new ArrayList();
+        List<Integer> parents = new ArrayList<>();
         for (int i = 0; i < p.length; i++) {
             if (!parents.contains(find(i))) {
                 parents.add(find(i));
diff --git a/src/main/java/com/thealgorithms/strings/WordLadder.java b/src/main/java/com/thealgorithms/strings/WordLadder.java
index a4634ce01ee0..e88acbd18586 100644
--- a/src/main/java/com/thealgorithms/strings/WordLadder.java
+++ b/src/main/java/com/thealgorithms/strings/WordLadder.java
@@ -51,13 +51,13 @@ class WordLadder {
      * if the endword is there. Otherwise, will return the length as 0.
      */
     public static int ladderLength(String beginWord, String endWord, List<String> wordList) {
-        HashSet<String> set = new HashSet(wordList);
+        HashSet<String> set = new HashSet<>(wordList);
 
         if (!set.contains(endWord)) {
             return 0;
         }
 
-        Queue<String> queue = new LinkedList();
+        Queue<String> queue = new LinkedList<>();
         queue.offer(beginWord);
         int level = 1;
 

From 9d1635a28baaa9d3cb908d8c0c4cb3de6fd6f41f Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 22 Mar 2024 11:32:13 +0100
Subject: [PATCH 0103/1338] chore: configure dependabot (#5081)

---
 .github/dependabot.yml | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 .github/dependabot.yml

diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 000000000000..f8f0befb770c
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,8 @@
+---
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/.github/workflows/"
+    schedule:
+      interval: "daily"
+...

From d4e4cd24cdb4a2fa1afdcb5224a50699d5ca248c Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 22 Mar 2024 11:38:44 +0100
Subject: [PATCH 0104/1338] Bump github/codeql-action from 2 to 3 in
 /.github/workflows (#5082)

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 2 to 3.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v2...v3)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index cea50a26c19a..0ab7611656a4 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -33,7 +33,7 @@ jobs:
           distribution: 'adopt'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v2
+        uses: github/codeql-action/init@v3
         with:
           languages: ${{ env.LANGUAGE }}
 
@@ -41,7 +41,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v2
+        uses: github/codeql-action/analyze@v3
         with:
           category: "/language:${{env.LANGUAGE}}"
 ...

From df20d919c83d2e9cefb750906022fda22a46a16b Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 22 Mar 2024 12:06:58 +0100
Subject: [PATCH 0105/1338] Bump actions/setup-java from 3 to 4 in
 /.github/workflows (#5083)

Bumps [actions/setup-java](https://github.com/actions/setup-java) from 3 to 4.
- [Release notes](https://github.com/actions/setup-java/releases)
- [Commits](https://github.com/actions/setup-java/compare/v3...v4)

---
updated-dependencies:
- dependency-name: actions/setup-java
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml  | 2 +-
 .github/workflows/codeql.yml | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 3a81c092f7eb..e725dfa74904 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -6,7 +6,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Set up JDK 17
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@v4
         with:
           java-version: 17
           distribution: 'adopt'
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 0ab7611656a4..f447eb954550 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -27,7 +27,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Set up JDK 17
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@v4
         with:
           java-version: 17
           distribution: 'adopt'

From 84f8cee332ac59e168899471a2bb9eabb02e6781 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 22 Mar 2024 19:10:09 +0800
Subject: [PATCH 0106/1338] Bump actions/setup-python from 4 to 5 in
 /.github/workflows (#5084)

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 4 to 5.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v4...v5)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/update_directory.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/update_directory.yml b/.github/workflows/update_directory.yml
index 3638e3529e0b..c811d244e54b 100644
--- a/.github/workflows/update_directory.yml
+++ b/.github/workflows/update_directory.yml
@@ -25,7 +25,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@master
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: '3.x'
       - name: Update Directory

From 098f04437024e004a1871cd93eb9ab7d1965a1cc Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 22 Mar 2024 12:18:08 +0100
Subject: [PATCH 0107/1338] Remove `CalculateMaxOfMin` (#5079)

---
 DIRECTORY.md                                  | 23 +++++---
 .../stacks/CalculateMaxOfMin.java             | 42 --------------
 .../stacks/CalculateMaxOfMinTest.java         | 57 -------------------
 3 files changed, 16 insertions(+), 106 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/stacks/CalculateMaxOfMin.java
 delete mode 100644 src/test/java/com/thealgorithms/stacks/CalculateMaxOfMinTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b621216da7f1..a75b521341fc 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -27,7 +27,6 @@
             * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
             * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
-            * [SetKthBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java)
             * [SingleBitOperations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java)
           * ciphers
             * a5
@@ -112,6 +111,7 @@
               * [MatrixGraphs](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java)
               * [PrimMST](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java)
               * [TarjansAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java)
+              * [WelshPowell](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java)
             * hashmap
               * hashing
                 * [GenericHashMapUsingArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java)
@@ -248,7 +248,7 @@
             * [ShortestCommonSupersequenceLength](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java)
             * [SubsetCount](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java)
             * [SubsetSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java)
-            * [Sum Of Subset](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Sum_Of_Subset.java)
+            * [SumOfSubset](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java)
             * [Tribonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java)
             * [UniquePaths](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java)
             * [WildcardMatching](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java)
@@ -260,6 +260,7 @@
             * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java)
             * [FractionalKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
             * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
+            * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java)
           * io
             * [BufferedReader](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/io/BufferedReader.java)
           * maths
@@ -271,6 +272,7 @@
             * [AmicableNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AmicableNumber.java)
             * [Area](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Area.java)
             * [Armstrong](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Armstrong.java)
+            * [AutoCorrelation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AutoCorrelation.java)
             * [AutomorphicNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java)
             * [Average](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Average.java)
             * [BinaryPow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinaryPow.java)
@@ -281,6 +283,7 @@
             * [Combinations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Combinations.java)
             * [Convolution](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Convolution.java)
             * [ConvolutionFFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java)
+            * [CrossCorrelation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CrossCorrelation.java)
             * [DeterminantOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java)
             * [DigitalRoot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DigitalRoot.java)
             * [DistanceFormula](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DistanceFormula.java)
@@ -368,8 +371,6 @@
             * [Volume](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Volume.java)
           * matrixexponentiation
             * [Fibonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java)
-          * minimizinglateness
-            * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/minimizinglateness/MinimizingLateness.java)
           * misc
             * [ColorContrastRatio](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java)
             * [InverseOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java)
@@ -451,6 +452,7 @@
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
             * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
+            * [SRTFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java)
           * searches
             * [BinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BinarySearch.java)
             * [BinarySearch2dArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java)
@@ -497,6 +499,7 @@
             * [DNFSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DNFSort.java)
             * [DualPivotQuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java)
             * [DutchNationalFlagSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java)
+            * [ExchangeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/ExchangeSort.java)
             * [GnomeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/GnomeSort.java)
             * [HeapSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/HeapSort.java)
             * [InsertionSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/InsertionSort.java)
@@ -526,7 +529,6 @@
             * [WiggleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/WiggleSort.java)
           * stacks
             * [BalancedBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java)
-            * [CalculateMaxOfMin](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/CalculateMaxOfMin.java)
             * [DecimalToAnyUsingStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java)
             * [DuplicateBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java)
             * [InfixToPostfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java)
@@ -587,7 +589,6 @@
             * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
             * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
-            * [SetKthBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java)
             * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
           * ciphers
             * a5
@@ -636,6 +637,7 @@
               * [HamiltonianCycleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java)
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
               * [TarjansAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
+              * [WelshPowellTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java)
             * hashmap
               * hashing
                 * [GenericHashMapUsingArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java)
@@ -691,6 +693,7 @@
             * [OptimalJobSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
             * [PartitionProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java)
             * [SubsetCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java)
+            * [SumOfSubsetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java)
             * [TribonacciTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java)
             * [UniquePathsTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java)
             * [WildcardMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java)
@@ -701,6 +704,7 @@
             * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java)
             * [FractionalKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
             * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
+            * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java)
           * io
             * [BufferedReaderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/io/BufferedReaderTest.java)
           * maths
@@ -712,6 +716,7 @@
             * [AmicableNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AmicableNumberTest.java)
             * [AreaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AreaTest.java)
             * [ArmstrongTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ArmstrongTest.java)
+            * [AutoCorrelationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AutoCorrelationTest.java)
             * [AutomorphicNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AutomorphicNumberTest.java)
             * [AverageTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AverageTest.java)
             * [BinaryPowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinaryPowTest.java)
@@ -719,6 +724,7 @@
             * [CeilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CeilTest.java)
             * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
             * [CombinationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CombinationsTest.java)
+            * [CrossCorrelationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java)
             * [DigitalRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DigitalRootTest.java)
             * [DistanceFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java)
             * [DudeneyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java)
@@ -792,6 +798,8 @@
             * [TwoSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
           * others
             * [ArrayLeftRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java)
+            * [ArrayRightRotation](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotation.java)
+            * [ArrayRightRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java)
             * [BestFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BestFitCPUTest.java)
             * [BoyerMooreTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BoyerMooreTest.java)
             * cn
@@ -822,6 +830,7 @@
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
             * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)
+            * [SRTFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java)
           * searches
             * [BinarySearch2dArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java)
             * [BreadthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java)
@@ -846,6 +855,7 @@
             * [CombSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CombSortTest.java)
             * [DualPivotQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java)
             * [DutchNationalFlagSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java)
+            * [ExchangeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/ExchangeSortTest.java)
             * [GnomeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/GnomeSortTest.java)
             * [HeapSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/HeapSortTest.java)
             * [InsertionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java)
@@ -868,7 +878,6 @@
             * [TreeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TreeSortTest.java)
             * [WiggleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java)
           * stacks
-            * [CalculateMaxOfMinTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/CalculateMaxOfMinTest.java)
             * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
           * strings
             * [AhoCorasickTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
diff --git a/src/main/java/com/thealgorithms/stacks/CalculateMaxOfMin.java b/src/main/java/com/thealgorithms/stacks/CalculateMaxOfMin.java
deleted file mode 100644
index 399b9efdc49b..000000000000
--- a/src/main/java/com/thealgorithms/stacks/CalculateMaxOfMin.java
+++ /dev/null
@@ -1,42 +0,0 @@
-/**
- * Author : Siddhant Swarup Mallick
- * Github : https://github.com/siddhant2002
- */
-
-/**
- * Program description - Given an integer array. The task is to find the maximum of the minimum of
- * the array
- */
-package com.thealgorithms.stacks;
-
-import java.util.*;
-
-public class CalculateMaxOfMin {
-
-    public static int calculateMaxOfMin(int[] a) {
-        int n = a.length;
-        int[] ans = new int[n];
-        int[] arr2 = Arrays.copyOf(a, n);
-        Arrays.sort(arr2);
-        int maxNum = arr2[arr2.length - 1];
-        ans[0] = maxNum;
-        int index = 1;
-        while (index != ans.length) {
-            int[] minimums = new int[n - index];
-            for (int i = 0; i < n - index; i++) {
-                int[] windowArray = Arrays.copyOfRange(a, i, i + index + 1);
-                Arrays.sort(windowArray);
-                int minNum = windowArray[0];
-                minimums[i] = minNum;
-            }
-            Arrays.sort(minimums);
-            ans[index] = minimums[minimums.length - 1];
-            index += 1;
-        }
-        return ans[0];
-    }
-}
-/**
- * Given an integer array. The task is to find the maximum of the minimum of the
- * given array
- */
diff --git a/src/test/java/com/thealgorithms/stacks/CalculateMaxOfMinTest.java b/src/test/java/com/thealgorithms/stacks/CalculateMaxOfMinTest.java
deleted file mode 100644
index 4cb1f48dce4a..000000000000
--- a/src/test/java/com/thealgorithms/stacks/CalculateMaxOfMinTest.java
+++ /dev/null
@@ -1,57 +0,0 @@
-package com.thealgorithms.stacks;
-
-import static org.junit.jupiter.api.Assertions.*;
-
-import org.junit.jupiter.api.Test;
-
-public class CalculateMaxOfMinTest {
-
-    @Test
-    void testForOneElement() {
-        int[] a = {10, 20, 30, 50, 10, 70, 30};
-        int k = CalculateMaxOfMin.calculateMaxOfMin(a);
-        assertEquals(70, k);
-    }
-
-    @Test
-    void testForTwoElements() {
-        int[] a = {5, 3, 2, 6, 3, 2, 6};
-        int k = CalculateMaxOfMin.calculateMaxOfMin(a);
-        assertEquals(6, k);
-    }
-
-    @Test
-    void testForThreeElements() {
-        int[] a = {10, 10, 10, 10, 10, 10, 10};
-        int k = CalculateMaxOfMin.calculateMaxOfMin(a);
-        assertEquals(10, k);
-    }
-
-    @Test
-    void testForFourElements() {
-        int[] a = {70, 60, 50, 40, 30, 20};
-        int k = CalculateMaxOfMin.calculateMaxOfMin(a);
-        assertEquals(70, k);
-    }
-
-    @Test
-    void testForFiveElements() {
-        int[] a = {50};
-        int k = CalculateMaxOfMin.calculateMaxOfMin(a);
-        assertEquals(50, k);
-    }
-
-    @Test
-    void testForSixElements() {
-        int[] a = {1, 4, 7, 9, 2, 4, 6};
-        int k = CalculateMaxOfMin.calculateMaxOfMin(a);
-        assertEquals(9, k);
-    }
-
-    @Test
-    void testForSevenElements() {
-        int[] a = {-1, -5, -7, -9, -12, -14};
-        int k = CalculateMaxOfMin.calculateMaxOfMin(a);
-        assertEquals(-1, k);
-    }
-}

From 71c5f27d85503c84449bdbe9232728a0a0a8bb95 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 22 Mar 2024 11:20:45 +0000
Subject: [PATCH 0108/1338] Bump actions/stale from 4 to 9 in
 /.github/workflows (#5085)

Bumps [actions/stale](https://github.com/actions/stale) from 4 to 9.
- [Release notes](https://github.com/actions/stale/releases)
- [Changelog](https://github.com/actions/stale/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/stale/compare/v4...v9)

---
updated-dependencies:
- dependency-name: actions/stale
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/stale.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index ee14629b2e41..6fb47c5d2dc9 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -6,7 +6,7 @@ jobs:
   stale:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/stale@v4
+      - uses: actions/stale@v9
         with:
           stale-issue-message: 'This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution!'
           close-issue-message: 'Please reopen this issue once you have made the required changes. If you need help, feel free to ask in our [Discord](https://the-algorithms.com/discord) server or ping one of the maintainers here. Thank you for your contribution!'

From da21ffe78c79d6b4e4d420f4ce862a1bedd2024e Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 26 Mar 2024 17:56:13 +0100
Subject: [PATCH 0109/1338] chore: configure dependabot to update docker files
 (#5086)

---
 .github/dependabot.yml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index f8f0befb770c..e568006bd634 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -1,6 +1,11 @@
 ---
 version: 2
 updates:
+  - package-ecosystem: "docker"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+
   - package-ecosystem: "github-actions"
     directory: "/.github/workflows/"
     schedule:

From 40cd4d86efad44d03e1de15bdf7fdb685ef0ce73 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 2 Apr 2024 23:52:17 +0530
Subject: [PATCH 0110/1338] Bump gitpod/workspace-java-17 from
 2023-08-30-14-07-38 to 2024-03-31-14-01-15 (#5092)

Bump gitpod/workspace-java-17

Bumps gitpod/workspace-java-17 from 2023-08-30-14-07-38 to 2024-03-31-14-01-15.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-17
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index e10a44af6132..03362b0ccb33 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-17:2023-08-30-14-07-38
+FROM gitpod/workspace-java-17:2024-03-31-14-01-15
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 22310defcd090089229528316b47e48974c42db9 Mon Sep 17 00:00:00 2001
From: Kanivets Kateryna <44711379+kanivetskateryna@users.noreply.github.com>
Date: Tue, 2 Apr 2024 21:26:06 +0200
Subject: [PATCH 0111/1338] Cleaned up code for some packages (#5094)

* Cleaned up code of some packages

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/conversions/IntegerToRoman.java  |  4 ++--
 .../com/thealgorithms/conversions/RomanToInteger.java  |  4 +---
 .../conversions/TurkishToLatinConversion.java          |  2 +-
 .../thealgorithms/dynamicprogramming/Fibonacci.java    |  5 ++---
 .../dynamicprogramming/MatrixChainMultiplication.java  | 10 +++++-----
 .../greedyalgorithms/ActivitySelection.java            |  4 ++--
 .../com/thealgorithms/greedyalgorithms/CoinChange.java |  4 +---
 .../greedyalgorithms/FractionalKnapsack.java           |  4 ++--
 .../thealgorithms/greedyalgorithms/JobSequencing.java  |  2 +-
 .../java/com/thealgorithms/searches/UnionFind.java     |  4 ++--
 src/main/java/com/thealgorithms/sorts/DNFSort.java     |  4 ++--
 src/main/java/com/thealgorithms/strings/Pangram.java   |  5 ++---
 12 files changed, 23 insertions(+), 29 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java b/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
index b81cfd773d75..aae0b3b29376 100644
--- a/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
+++ b/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
@@ -9,7 +9,7 @@
  */
 public class IntegerToRoman {
 
-    private static int[] allArabianRomanNumbers = new int[] {
+    private static final int[] allArabianRomanNumbers = new int[] {
         1000,
         900,
         500,
@@ -24,7 +24,7 @@ public class IntegerToRoman {
         4,
         1,
     };
-    private static String[] allRomanNumbers = new String[] {
+    private static final String[] allRomanNumbers = new String[] {
         "M",
         "CM",
         "D",
diff --git a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
index fddb56232c58..d5dc79872a67 100644
--- a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
+++ b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
@@ -4,9 +4,7 @@
 
 public class RomanToInteger {
 
-    private static Map<Character, Integer> map = new HashMap<Character, Integer>() {
-        /**
-         *          */
+    private static final Map<Character, Integer> map = new HashMap<>() {
         private static final long serialVersionUID = 87605733047260530L;
 
         {
diff --git a/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java b/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
index d991f5f31faf..a96791b7706b 100644
--- a/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
+++ b/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
@@ -58,7 +58,7 @@ public static String convertTurkishToLatin(String param) {
             'G',
         };
         for (int i = 0; i < turkishChars.length; i++) {
-            param = param.replaceAll(new String(new char[] {turkishChars[i]}), new String(new char[] {latinChars[i]}));
+            param = param.replaceAll(String.valueOf(turkishChars[i]), String.valueOf(latinChars[i]));
         }
         return param;
     }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
index f2a3b2b8f542..c2e921c3aa36 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
@@ -9,7 +9,7 @@
  */
 public class Fibonacci {
 
-    private static Map<Integer, Integer> map = new HashMap<>();
+    private static final Map<Integer, Integer> map = new HashMap<>();
 
     public static void main(String[] args) {
         // Methods all returning [0, 1, 1, 2, 3, 5, ...] for n = [0, 1, 2, 3, 4, 5, ...]
@@ -106,7 +106,6 @@ public static int fibOptimized(int n) {
     public static int fibBinet(int n) {
         double squareRootOf5 = Math.sqrt(5);
         double phi = (1 + squareRootOf5) / 2;
-        int nthTerm = (int) ((Math.pow(phi, n) - Math.pow(-phi, -n)) / squareRootOf5);
-        return nthTerm;
+        return (int) ((Math.pow(phi, n) - Math.pow(-phi, -n)) / squareRootOf5);
     }
 }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
index 6dec5b418c50..af0447b95e67 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
@@ -6,8 +6,8 @@
 
 public class MatrixChainMultiplication {
 
-    private static Scanner scan = new Scanner(System.in);
-    private static ArrayList<Matrix> mArray = new ArrayList<>();
+    private static final Scanner scan = new Scanner(System.in);
+    private static final ArrayList<Matrix> mArray = new ArrayList<>();
     private static int size;
     private static int[][] m;
     private static int[][] s;
@@ -115,9 +115,9 @@ private static String[] input(String string) {
 
 class Matrix {
 
-    private int count;
-    private int col;
-    private int row;
+    private final int count;
+    private final int col;
+    private final int row;
 
     Matrix(int count, int col, int row) {
         this.count = count;
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java b/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
index 0f704dd6ed55..6909c564fe96 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
@@ -8,9 +8,9 @@
 
 public class ActivitySelection {
     // Function to perform activity selection
-    public static ArrayList<Integer> activitySelection(int startTimes[], int endTimes[]) {
+    public static ArrayList<Integer> activitySelection(int[] startTimes, int[] endTimes) {
         int n = startTimes.length;
-        int activities[][] = new int[n][3];
+        int[][] activities = new int[n][3];
 
         // Create a 2D array to store activities and their start/end times.
         // Each row: [activity index, start time, end time]
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java b/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
index 2109e454fa4d..560adf8eb84c 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
@@ -10,12 +10,11 @@ public class CoinChange {
     // Function to solve the coin change problem
     public static ArrayList<Integer> coinChangeProblem(int amount) {
         // Define an array of coin denominations in descending order
-        Integer coins[] = {1, 2, 5, 10, 20, 50, 100, 500, 2000};
+        Integer[] coins = {1, 2, 5, 10, 20, 50, 100, 500, 2000};
 
         // Sort the coin denominations in descending order
         Arrays.sort(coins, Comparator.reverseOrder());
 
-        int count = 0; // Variable to keep track of the total number of coins used
         ArrayList<Integer> ans = new ArrayList<>(); // List to store selected coins
 
         // Iterate through the coin denominations
@@ -24,7 +23,6 @@ public static ArrayList<Integer> coinChangeProblem(int amount) {
             if (coins[i] <= amount) {
                 // Repeatedly subtract the coin denomination from the remaining amount
                 while (coins[i] <= amount) {
-                    count++; // Increment the count of coins used
                     ans.add(coins[i]); // Add the coin to the list of selected coins
                     amount -= coins[i]; // Update the remaining amount
                 }
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java b/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
index f46364fc704b..d13cafb0978a 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
@@ -7,9 +7,9 @@
 
 public class FractionalKnapsack {
     // Function to perform fractional knapsack
-    public static int fractionalKnapsack(int weight[], int value[], int capacity) {
+    public static int fractionalKnapsack(int[] weight, int[] value, int capacity) {
         // Create a 2D array to store item indices and their value-to-weight ratios.
-        double ratio[][] = new double[weight.length][2];
+        double[][] ratio = new double[weight.length][2];
 
         // Populate the ratio array with item indices and their value-to-weight ratios.
         for (int i = 0; i < weight.length; i++) {
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
index 4d2cf7c95a03..83ed40d2a1be 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
@@ -31,7 +31,7 @@ public static String findJobSequence(ArrayList<Job> jobs, int size) {
         Boolean[] slots = new Boolean[size];
         Arrays.fill(slots, false);
 
-        int result[] = new int[size];
+        int[] result = new int[size];
 
         // Iterate through jobs to find the optimal job sequence
         for (int i = 0; i < size; i++) {
diff --git a/src/main/java/com/thealgorithms/searches/UnionFind.java b/src/main/java/com/thealgorithms/searches/UnionFind.java
index 4dfece0e6381..20f524785f28 100644
--- a/src/main/java/com/thealgorithms/searches/UnionFind.java
+++ b/src/main/java/com/thealgorithms/searches/UnionFind.java
@@ -4,8 +4,8 @@
 
 public class UnionFind {
 
-    private int[] p;
-    private int[] r;
+    private final int[] p;
+    private final int[] r;
 
     public UnionFind(int n) {
         p = new int[n];
diff --git a/src/main/java/com/thealgorithms/sorts/DNFSort.java b/src/main/java/com/thealgorithms/sorts/DNFSort.java
index 7e18b657973f..7f50deca47aa 100644
--- a/src/main/java/com/thealgorithms/sorts/DNFSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DNFSort.java
@@ -7,7 +7,7 @@ public class DNFSort {
     static void sort012(int[] a, int arr_size) {
         int low = 0;
         int high = arr_size - 1;
-        int mid = 0, temp = 0;
+        int mid = 0, temp;
         while (mid <= high) {
             switch (a[mid]) {
             case 0: {
@@ -37,7 +37,7 @@ static void printArray(int[] arr, int arr_size) {
         for (int i = 0; i < arr_size; i++) {
             System.out.print(arr[i] + " ");
         }
-        System.out.println("");
+        System.out.println();
     }
 
     /*Driver function to check for above functions*/
diff --git a/src/main/java/com/thealgorithms/strings/Pangram.java b/src/main/java/com/thealgorithms/strings/Pangram.java
index 9d734579406c..d2c9f3e5baa0 100644
--- a/src/main/java/com/thealgorithms/strings/Pangram.java
+++ b/src/main/java/com/thealgorithms/strings/Pangram.java
@@ -25,12 +25,11 @@ public static void main(String[] args) {
      */
     // alternative approach using Java Collection Framework
     public static boolean isPangramUsingSet(String s) {
-        HashSet<Character> alpha = new HashSet<Character>();
+        HashSet<Character> alpha = new HashSet<>();
         s = s.trim().toLowerCase();
         for (int i = 0; i < s.length(); i++)
             if (s.charAt(i) != ' ') alpha.add(s.charAt(i));
-        if (alpha.size() == 26) return true;
-        return false;
+        return alpha.size() == 26;
     }
 
     /**

From c53f178308728a1a31702a7702e902f2f17192d1 Mon Sep 17 00:00:00 2001
From: SOZEL <80200848+TruongNhanNguyen@users.noreply.github.com>
Date: Fri, 5 Apr 2024 23:41:27 +0700
Subject: [PATCH 0112/1338] Implement Parentheses Generator (#5096)

* chore: add `ParenthesesGenerator` to `DIRECTORY.md`

* feat: implement Parentheses Generator

* ref: change `ParenthesesGenerator`s method to `static`

* ref: use parametrized tests

* ref: handling exception when `n < 0`

* chore: update docstrings

* ref: make `ParenthesesGenerator` to be a proper utility

* chore(docs): add private constructor docstring

* ref(tests): move bad name suggestions

* style: remove reduntant comments

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 DIRECTORY.md                                  |  1 +
 .../backtracking/ParenthesesGenerator.java    | 50 +++++++++++++++++++
 .../ParenthesesGeneratorTest.java             | 33 ++++++++++++
 3 files changed, 84 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java
 create mode 100644 src/test/java/com/thealgorithms/backtracking/ParenthesesGeneratorTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a75b521341fc..36989c416513 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -15,6 +15,7 @@
             * [MazeRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java)
             * [MColoring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/MColoring.java)
             * [NQueens](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/NQueens.java)
+            * [ParenthesesGenerator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java)
             * [Permutation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/Permutation.java)
             * [PowerSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/PowerSum.java)
             * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
diff --git a/src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java b/src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java
new file mode 100644
index 000000000000..8bbed4106251
--- /dev/null
+++ b/src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java
@@ -0,0 +1,50 @@
+package com.thealgorithms.backtracking;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * This class generates all valid combinations of parentheses for a given number of pairs using backtracking.
+ */
+public final class ParenthesesGenerator {
+    private ParenthesesGenerator() {
+    }
+
+    /**
+     * Generates all valid combinations of parentheses for a given number of pairs.
+     *
+     * @param n The number of pairs of parentheses.
+     * @return A list of strings representing valid combinations of parentheses.
+     * @throws IllegalArgumentException if n is less than 0.
+     */
+    public static List<String> generateParentheses(final int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("The number of pairs of parentheses cannot be nagative");
+        }
+        List<String> result = new ArrayList<>();
+        generateParenthesesHelper(result, "", 0, 0, n);
+        return result;
+    }
+
+    /**
+     * Helper function for generating all valid combinations of parentheses recursively.
+     *
+     * @param result  The list to store valid combinations.
+     * @param current The current combination being formed.
+     * @param open    The number of open parentheses.
+     * @param close   The number of closed parentheses.
+     * @param n       The total number of pairs of parentheses.
+     */
+    private static void generateParenthesesHelper(List<String> result, final String current, final int open, final int close, final int n) {
+        if (current.length() == n * 2) {
+            result.add(current);
+            return;
+        }
+        if (open < n) {
+            generateParenthesesHelper(result, current + "(", open + 1, close, n);
+        }
+        if (close < open) {
+            generateParenthesesHelper(result, current + ")", open, close + 1, n);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/backtracking/ParenthesesGeneratorTest.java b/src/test/java/com/thealgorithms/backtracking/ParenthesesGeneratorTest.java
new file mode 100644
index 000000000000..9da16061d8f4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/backtracking/ParenthesesGeneratorTest.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.backtracking;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class ParenthesesGeneratorTest {
+    @ParameterizedTest
+    @MethodSource("regularInputStream")
+    void regularInputTests(int input, List<String> expected) {
+        assertEquals(expected, ParenthesesGenerator.generateParentheses(input));
+    }
+
+    @ParameterizedTest
+    @MethodSource("negativeInputStream")
+    void throwsForNegativeInputTests(int input) {
+        assertThrows(IllegalArgumentException.class, () -> ParenthesesGenerator.generateParentheses(input));
+    }
+
+    private static Stream<Arguments> regularInputStream() {
+        return Stream.of(Arguments.of(0, List.of("")), Arguments.of(1, List.of("()")), Arguments.of(2, List.of("(())", "()()")), Arguments.of(3, List.of("((()))", "(()())", "(())()", "()(())", "()()()")),
+            Arguments.of(4, List.of("(((())))", "((()()))", "((())())", "((()))()", "(()(()))", "(()()())", "(()())()", "(())(())", "(())()()", "()((()))", "()(()())", "()(())()", "()()(())", "()()()()")));
+    }
+
+    private static Stream<Arguments> negativeInputStream() {
+        return Stream.of(Arguments.of(-1), Arguments.of(-5), Arguments.of(-10));
+    }
+}

From ab094ef04d489323ef802e0cbe3a23cfb0751aa7 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 6 Apr 2024 17:06:30 +0200
Subject: [PATCH 0113/1338] chore: generate coverage report and upload it to
 codecov (#5098)

---
 .github/workflows/build.yml |  9 +++++++++
 pom.xml                     | 26 ++++++++++++++++++++++++--
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e725dfa74904..5b617a86dca2 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -1,5 +1,9 @@
 name: Build
 on: [push, pull_request]
+
+env:
+  COVERAGE_REPORT_PATH: "target/site/jacoco/jacoco.xml"
+
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -12,3 +16,8 @@ jobs:
           distribution: 'adopt'
       - name: Build with Maven
         run: mvn --batch-mode --update-snapshots verify
+      - name: Upload coverage to codecov
+        uses: codecov/codecov-action@v3
+        with:
+          files: "${{ env.REPORT_NAME }}"
+          fail_ci_if_error: true
diff --git a/pom.xml b/pom.xml
index 86922e1f0a98..23f90f682158 100644
--- a/pom.xml
+++ b/pom.xml
@@ -63,7 +63,10 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>2.22.2</version>
+                <version>3.2.5</version>
+                <configuration>
+                    <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
+                </configuration>
             </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
@@ -74,6 +77,25 @@
                     <target>17</target>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.jacoco</groupId>
+                <artifactId>jacoco-maven-plugin</artifactId>
+                <version>0.8.12</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>prepare-agent</goal>
+                        </goals>
+                    </execution>
+                    <execution>
+                        <id>generate-code-coverage-report</id>
+                        <phase>test</phase>
+                        <goals>
+                            <goal>report</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
     </build>
-</project>
\ No newline at end of file
+</project>

From 295ac4b1ac2d43a4dea643380b6428a11c64500c Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 6 Apr 2024 20:50:15 +0200
Subject: [PATCH 0114/1338] Update `codecov/codecov-action` to `v4` (#5100)

---
 .github/workflows/build.yml | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 5b617a86dca2..19f84e023a5b 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -1,9 +1,6 @@
 name: Build
 on: [push, pull_request]
 
-env:
-  COVERAGE_REPORT_PATH: "target/site/jacoco/jacoco.xml"
-
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -16,8 +13,19 @@ jobs:
           distribution: 'adopt'
       - name: Build with Maven
         run: mvn --batch-mode --update-snapshots verify
-      - name: Upload coverage to codecov
-        uses: codecov/codecov-action@v3
+      - name: Upload coverage to codecov (tokenless)
+        if: >-
+          github.event_name == 'pull_request' &&
+          github.event.pull_request.head.repo.full_name != github.repository
+        uses: codecov/codecov-action@v4
+        with:
+          fail_ci_if_error: true
+      - name: Upload coverage to codecov (with token)
+        if: >
+          github.repository == 'TheAlgorithms/Java' &&
+          (github.event_name != 'pull_request' ||
+          github.event.pull_request.head.repo.full_name == github.repository)
+        uses: codecov/codecov-action@v4
         with:
-          files: "${{ env.REPORT_NAME }}"
+          token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true

From 90704d736bc3d64592aa3a994d7b86eb61fe6121 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 8 Apr 2024 19:38:31 +0200
Subject: [PATCH 0115/1338] fix: update `clang-format` tag (#5095)

---
 .gitpod.dockerfile | 2 +-
 DIRECTORY.md       | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 03362b0ccb33..6cf2fb177639 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -11,7 +11,7 @@ USER root
 RUN ./"$LLVM_SCRIPT" 16 \
   && apt-get update \
   && apt-get install -y --no-install-recommends \
-  clang-format-16=1:16.0.6~++20230710042027+7cbf1a259152-1~exp1~20230710162048.105 \
+  clang-format-16=1:16.0.6~++20231112100510+7cbf1a259152-1~exp1~20231112100554.106 \
   && apt-get clean \
   && rm -rf /var/lib/apt/lists/*
 
diff --git a/DIRECTORY.md b/DIRECTORY.md
index 36989c416513..a48e01f4ac04 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -578,6 +578,7 @@
             * [FloodFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/FloodFillTest.java)
             * [MazeRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java)
             * [MColoringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/MColoringTest.java)
+            * [ParenthesesGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/ParenthesesGeneratorTest.java)
             * [PermutationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PermutationTest.java)
             * [PowerSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PowerSumTest.java)
             * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)

From f490b5936a153ae42bdc746fccac998e6e04b6c6 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 8 Apr 2024 20:08:35 +0200
Subject: [PATCH 0116/1338] docs: add codecov badge (#5099)

Continuation of #5098.
---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index 16237a32f974..d60d5104c385 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,7 @@
 # The Algorithms - Java
 
 [![Build](https://github.com/TheAlgorithms/Java/actions/workflows/build.yml/badge.svg?branch=master)](https://github.com/TheAlgorithms/Java/actions/workflows/build.yml)
+[![codecov](https://codecov.io/gh/TheAlgorithms/Java/graph/badge.svg?token=XAdPyqTIqR)](https://codecov.io/gh/TheAlgorithms/Java)
 [![Discord chat](https://img.shields.io/discord/808045925556682782.svg?logo=discord&colorB=7289DA&style=flat-square)](https://discord.gg/c7MnfGFGa6)
 [![Gitpod ready-to-code](https://img.shields.io/badge/Gitpod-ready--to--code-blue?logo=gitpod)](https://gitpod.io/#https://github.com/TheAlgorithms/Java)
 

From 4697b87753b25490a43adaaf12dc49cd78efd80d Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 8 Apr 2024 20:10:15 +0200
Subject: [PATCH 0117/1338] chore: update maven dependencies (#5101)

---
 pom.xml | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/pom.xml b/pom.xml
index 23f90f682158..f81894dcaf7e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>17</maven.compiler.source>
         <maven.compiler.target>17</maven.compiler.target>
-        <assertj.version>3.23.1</assertj.version>
+        <assertj.version>3.25.3</assertj.version>
     </properties>
 
     <dependencyManagement>
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.8.2</version>
+                <version>5.10.2</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
@@ -31,7 +31,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.9.0</version>
+            <version>5.10.2</version>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -44,18 +44,18 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>5.9.0</version>
+            <version>5.10.2</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
-            <version>3.12.0</version>
+            <version>3.14.0</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-collections4</artifactId>
-            <version>4.4</version>
+            <version>4.5.0-M1</version>
         </dependency>
     </dependencies>
 

From 91cdf0453a78c759a0ad6ef1389c7f27c071ab6b Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 9 Apr 2024 19:03:13 +0200
Subject: [PATCH 0118/1338] Chore(deps): bump gitpod/workspace-java-17 from
 2024-03-31-14-01-15 to 2024-04-07-21-39-34 (#5103)

Chore(deps): bump gitpod/workspace-java-17

Bumps gitpod/workspace-java-17 from 2024-03-31-14-01-15 to 2024-04-07-21-39-34.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-17
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 6cf2fb177639..36c2e0a19a06 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-17:2024-03-31-14-01-15
+FROM gitpod/workspace-java-17:2024-04-07-21-39-34
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From f39bb8f32f158c8b3f2e350ced006be6cd015c7a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 12 Apr 2024 08:36:46 +0200
Subject: [PATCH 0119/1338] Chore(deps): bump DoozyX/clang-format-lint-action
 from 0.16.2 to 0.17 in /.github/workflows (#5105)

Chore(deps): bump DoozyX/clang-format-lint-action in /.github/workflows

Bumps [DoozyX/clang-format-lint-action](https://github.com/doozyx/clang-format-lint-action) from 0.16.2 to 0.17.
- [Release notes](https://github.com/doozyx/clang-format-lint-action/releases)
- [Commits](https://github.com/doozyx/clang-format-lint-action/compare/v0.16.2...v0.17)

---
updated-dependencies:
- dependency-name: DoozyX/clang-format-lint-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/clang-format-lint.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/clang-format-lint.yml b/.github/workflows/clang-format-lint.yml
index 90c0550dc31b..7f3cb3d5162f 100644
--- a/.github/workflows/clang-format-lint.yml
+++ b/.github/workflows/clang-format-lint.yml
@@ -9,7 +9,7 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-    - uses: DoozyX/clang-format-lint-action@v0.16.2
+    - uses: DoozyX/clang-format-lint-action@v0.17
       with:
         source: './src'
         extensions: 'java'

From 7201dc78adf418b22a9151f1780dafebb86e751b Mon Sep 17 00:00:00 2001
From: marysiuniq <67139391+marysiuniq@users.noreply.github.com>
Date: Sat, 13 Apr 2024 20:45:07 +0200
Subject: [PATCH 0120/1338] Added tests for NumberOfDigits (#5107)

Co-authored-by: Maria Paszkiewicz SCC <maria.paszkiewicz@kit.edu>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../thealgorithms/maths/NumberOfDigits.java   | 31 +++-----------
 .../maths/NumberOfDigitsTest.java             | 40 +++++++++++++++++++
 2 files changed, 46 insertions(+), 25 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java

diff --git a/src/main/java/com/thealgorithms/maths/NumberOfDigits.java b/src/main/java/com/thealgorithms/maths/NumberOfDigits.java
index 665d8ef5a98c..fc538196c7da 100644
--- a/src/main/java/com/thealgorithms/maths/NumberOfDigits.java
+++ b/src/main/java/com/thealgorithms/maths/NumberOfDigits.java
@@ -3,35 +3,16 @@
 /**
  * Find the number of digits in a number.
  */
-public class NumberOfDigits {
-
-    public static void main(String[] args) {
-        int[] numbers = {
-            0,
-            12,
-            123,
-            1234,
-            -12345,
-            123456,
-            1234567,
-            12345678,
-            123456789,
-        };
-        for (int i = 0; i < numbers.length; ++i) {
-            assert numberOfDigits(numbers[i]) == i + 1;
-            assert numberOfDigitsFast(numbers[i]) == i + 1;
-            assert numberOfDigitsFaster(numbers[i]) == i + 1;
-            assert numberOfDigitsRecursion(numbers[i]) == i + 1;
-        }
+public final class NumberOfDigits {
+    private NumberOfDigits() {
     }
-
     /**
      * Find the number of digits in a number.
      *
      * @param number number to find
      * @return number of digits of given number
      */
-    private static int numberOfDigits(int number) {
+    public static int numberOfDigits(int number) {
         int digits = 0;
         do {
             digits++;
@@ -46,7 +27,7 @@ private static int numberOfDigits(int number) {
      * @param number number to find
      * @return number of digits of given number
      */
-    private static int numberOfDigitsFast(int number) {
+    public static int numberOfDigitsFast(int number) {
         return number == 0 ? 1 : (int) Math.floor(Math.log10(Math.abs(number)) + 1);
     }
 
@@ -56,7 +37,7 @@ private static int numberOfDigitsFast(int number) {
      * @param number number to find
      * @return number of digits of given number
      */
-    private static int numberOfDigitsFaster(int number) {
+    public static int numberOfDigitsFaster(int number) {
         return number < 0 ? (-number + "").length() : (number + "").length();
     }
 
@@ -66,7 +47,7 @@ private static int numberOfDigitsFaster(int number) {
      * @param number number to find
      * @return number of digits of given number
      */
-    private static int numberOfDigitsRecursion(int number) {
+    public static int numberOfDigitsRecursion(int number) {
         return number / 10 == 0 ? 1 : 1 + numberOfDigitsRecursion(number / 10);
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java b/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
new file mode 100644
index 000000000000..2e807db12fb9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
@@ -0,0 +1,40 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.function.IntFunction;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class NumberOfDigitsTest {
+
+    @ParameterizedTest
+    @MethodSource("testCases")
+    void testNumberOfDigits(final int expected, final int number, final IntFunction<Integer> methodUnderTest) {
+        assertEquals(expected, methodUnderTest.apply(number));
+        assertEquals(expected, methodUnderTest.apply(-number));
+    }
+
+    private static Stream<Arguments> testCases() {
+        final Integer[][] inputs = new Integer[][] {
+            {3, 100},
+            {1, 0},
+            {2, 12},
+            {3, 123},
+            {4, 1234},
+            {5, 12345},
+            {6, 123456},
+            {7, 1234567},
+            {8, 12345678},
+            {9, 123456789},
+            {9, 987654321},
+        };
+
+        final IntFunction<Integer>[] methods = new IntFunction[] {NumberOfDigits::numberOfDigits, NumberOfDigits::numberOfDigitsFast, NumberOfDigits::numberOfDigitsFaster, NumberOfDigits::numberOfDigitsRecursion};
+
+        return Stream.of(inputs).flatMap(input -> Stream.of(methods).map(method -> Arguments.of(input[0], input[1], method)));
+    }
+}

From 05626f7a797a274b7aef73c4c3288fd4a6b36256 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 16 Apr 2024 18:33:15 +0200
Subject: [PATCH 0121/1338] Chore(deps): bump gitpod/workspace-java-17 from
 2024-04-07-21-39-34 to 2024-04-15-14-41-42 (#5108)

Chore(deps): bump gitpod/workspace-java-17

Bumps gitpod/workspace-java-17 from 2024-04-07-21-39-34 to 2024-04-15-14-41-42.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-17
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 36c2e0a19a06..ad3fba65e122 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-17:2024-04-07-21-39-34
+FROM gitpod/workspace-java-17:2024-04-15-14-41-42
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 8129686e2ea52bf02a1b966e812480cca5d2d1ed Mon Sep 17 00:00:00 2001
From: marysiuniq <67139391+marysiuniq@users.noreply.github.com>
Date: Sat, 20 Apr 2024 20:31:13 +0200
Subject: [PATCH 0122/1338] Added tests for `FactorialRecursion` (#5109)

* Added tests for `FactorialRecursion`

* Apply suggestions from code review

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

---------

Co-authored-by: Maria Paszkiewicz SCC <maria.paszkiewicz@kit.edu>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../maths/FactorialRecursion.java             | 12 ++-------
 .../maths/FactorialRecursionTest.java         | 27 +++++++++++++++++++
 2 files changed, 29 insertions(+), 10 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java

diff --git a/src/main/java/com/thealgorithms/maths/FactorialRecursion.java b/src/main/java/com/thealgorithms/maths/FactorialRecursion.java
index 85e03c4dd1a4..d9bafd1e39e9 100644
--- a/src/main/java/com/thealgorithms/maths/FactorialRecursion.java
+++ b/src/main/java/com/thealgorithms/maths/FactorialRecursion.java
@@ -1,16 +1,8 @@
 package com.thealgorithms.maths;
 
-public class FactorialRecursion {
-
-    /* Driver Code */
-    public static void main(String[] args) {
-        assert factorial(0) == 1;
-        assert factorial(1) == 1;
-        assert factorial(2) == 2;
-        assert factorial(3) == 6;
-        assert factorial(5) == 120;
+public final class FactorialRecursion {
+    private FactorialRecursion() {
     }
-
     /**
      * Recursive FactorialRecursion Method
      *
diff --git a/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java b/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java
new file mode 100644
index 000000000000..db18b46356b4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java
@@ -0,0 +1,27 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class FactorialRecursionTest {
+    @ParameterizedTest
+    @MethodSource("inputStream")
+    void testFactorialRecursion(long expected, int number) {
+        assertEquals(expected, FactorialRecursion.factorial(number));
+    }
+
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of(1, 0), Arguments.of(1, 1), Arguments.of(2, 2), Arguments.of(6, 3), Arguments.of(120, 5));
+    }
+
+    @Test
+    void testThrowsForNegativeInput() {
+        assertThrows(IllegalArgumentException.class, () -> FactorialRecursion.factorial(-1));
+    }
+}

From ac598e2b93a47a91b67530b799ad78c275a854ba Mon Sep 17 00:00:00 2001
From: marysiuniq <67139391+marysiuniq@users.noreply.github.com>
Date: Sun, 21 Apr 2024 21:02:32 +0200
Subject: [PATCH 0123/1338] Remove unused import. (#5113)

Co-authored-by: Maria Paszkiewicz SCC <maria.paszkiewicz@kit.edu>
---
 src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java b/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
index 2e807db12fb9..799052b22d83 100644
--- a/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
+++ b/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
@@ -4,7 +4,6 @@
 
 import java.util.function.IntFunction;
 import java.util.stream.Stream;
-import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;

From 089b1f7c928143fe63a9e7b6b651a50ca50ca9ad Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 23 Apr 2024 21:28:05 +0200
Subject: [PATCH 0124/1338] Chore(deps): bump gitpod/workspace-java-17 from
 2024-04-15-14-41-42 to 2024-04-16-12-16-24 (#5115)

Chore(deps): bump gitpod/workspace-java-17

Bumps gitpod/workspace-java-17 from 2024-04-15-14-41-42 to 2024-04-16-12-16-24.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-17
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index ad3fba65e122..89a19f3627cf 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-17:2024-04-15-14-41-42
+FROM gitpod/workspace-java-17:2024-04-16-12-16-24
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 7a42f68b66dfc7a53d67125f9685a2db0a5e2dd9 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 24 Apr 2024 14:22:42 +0200
Subject: [PATCH 0125/1338] chore: configure `checkstyle` (#5110)

---
 .github/workflows/build.yml |   2 +
 checkstyle.xml              | 198 ++++++++++++++++++++++++++++++++++++
 pom.xml                     |  18 ++++
 3 files changed, 218 insertions(+)
 create mode 100644 checkstyle.xml

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 19f84e023a5b..49821b917fd2 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -29,3 +29,5 @@ jobs:
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true
+      - name: Checkstyle
+        run: mvn checkstyle:check
diff --git a/checkstyle.xml b/checkstyle.xml
new file mode 100644
index 000000000000..6f635c7af61d
--- /dev/null
+++ b/checkstyle.xml
@@ -0,0 +1,198 @@
+<?xml version="1.0"?>
+<!DOCTYPE module PUBLIC
+          "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
+          "https://checkstyle.org/dtds/configuration_1_3.dtd">
+
+<!--
+
+  Checkstyle configuration that checks the sun coding conventions from:
+
+    - the Java Language Specification at
+      https://docs.oracle.com/javase/specs/jls/se11/html/index.html
+
+    - the Sun Code Conventions at https://www.oracle.com/java/technologies/javase/codeconventions-contents.html
+
+    - the Javadoc guidelines at
+      https://www.oracle.com/technical-resources/articles/java/javadoc-tool.html
+
+    - the JDK Api documentation https://docs.oracle.com/en/java/javase/11/
+
+    - some best practices
+
+  Checkstyle is very configurable. Be sure to read the documentation at
+  https://checkstyle.org (or in your downloaded distribution).
+
+  Most Checks are configurable, be sure to consult the documentation.
+
+  To completely disable a check, just comment it out or delete it from the file.
+  To suppress certain violations please review suppression filters.
+
+  Finally, it is worth reading the documentation.
+
+-->
+
+<module name="Checker">
+  <!--
+      If you set the basedir property below, then all reported file
+      names will be relative to the specified directory. See
+      https://checkstyle.org/config.html#Checker
+
+      <property name="basedir" value="${basedir}"/>
+  -->
+  <property name="severity" value="error"/>
+
+  <property name="fileExtensions" value="java, properties, xml"/>
+
+  <!-- Excludes all 'module-info.java' files              -->
+  <!-- See https://checkstyle.org/filefilters/index.html -->
+  <module name="BeforeExecutionExclusionFileFilter">
+    <property name="fileNamePattern" value="module\-info\.java$"/>
+  </module>
+
+  <!-- https://checkstyle.org/filters/suppressionfilter.html -->
+  <module name="SuppressionFilter">
+    <property name="file" value="${org.checkstyle.sun.suppressionfilter.config}"
+              default="checkstyle-suppressions.xml" />
+    <property name="optional" value="true"/>
+  </module>
+
+  <!-- Checks that a package-info.java file exists for each package.     -->
+  <!-- See https://checkstyle.org/checks/javadoc/javadocpackage.html#JavadocPackage -->
+  <!-- TODO <module name="JavadocPackage"/> -->
+
+  <!-- Checks whether files end with a new line.                        -->
+  <!-- See https://checkstyle.org/checks/misc/newlineatendoffile.html -->
+  <module name="NewlineAtEndOfFile"/>
+
+  <!-- Checks that property files contain the same keys.         -->
+  <!-- See https://checkstyle.org/checks/misc/translation.html -->
+  <module name="Translation"/>
+
+  <!-- Checks for Size Violations.                    -->
+  <!-- See https://checkstyle.org/checks/sizes/index.html -->
+  <!-- TODO <module name="FileLength"/> -->
+  <!-- TODO <module name="LineLength">
+    <property name="fileExtensions" value="java"/>
+  </module> -->
+
+  <!-- Checks for whitespace                               -->
+  <!-- See https://checkstyle.org/checks/whitespace/index.html -->
+  <!-- TODO <module name="FileTabCharacter"/> -->
+
+  <!-- Miscellaneous other checks.                   -->
+  <!-- See https://checkstyle.org/checks/misc/index.html -->
+  <module name="RegexpSingleline">
+    <property name="format" value="\s+$"/>
+    <property name="minimum" value="0"/>
+    <property name="maximum" value="0"/>
+    <property name="message" value="Line has trailing spaces."/>
+  </module>
+
+  <!-- Checks for Headers                                -->
+  <!-- See https://checkstyle.org/checks/header/index.html   -->
+  <!-- <module name="Header"> -->
+  <!--   <property name="headerFile" value="${checkstyle.header.file}"/> -->
+  <!--   <property name="fileExtensions" value="java"/> -->
+  <!-- </module> -->
+
+  <module name="TreeWalker">
+
+    <!-- Checks for Javadoc comments.                     -->
+    <!-- See https://checkstyle.org/checks/javadoc/index.html -->
+    <!-- TODO <module name="InvalidJavadocPosition"/> -->
+    <!-- TODO <module name="JavadocMethod"/> -->
+    <!-- TODO <module name="JavadocType"/> -->
+    <!-- TODO <module name="JavadocVariable"/> -->
+    <!-- TODO <module name="JavadocStyle"/> -->
+    <!-- TODO <module name="MissingJavadocMethod"/> -->
+
+    <!-- Checks for Naming Conventions.                  -->
+    <!-- See https://checkstyle.org/checks/naming/index.html -->
+    <!-- TODO <module name="ConstantName"/> -->
+    <!-- TODO <module name="LocalFinalVariableName"/> -->
+    <!-- TODO <module name="LocalVariableName"/> -->
+    <!-- TODO <module name="MemberName"/> -->
+    <!-- TODO <module name="MethodName"/> -->
+    <module name="PackageName"/>
+    <!-- TODO <module name="ParameterName"/> -->
+    <!-- TODO <module name="StaticVariableName"/> -->
+    <!-- TODO <module name="TypeName"/> -->
+
+    <!-- Checks for imports                              -->
+    <!-- See https://checkstyle.org/checks/imports/index.html -->
+    <!-- TODO <module name="AvoidStarImport"/> -->
+    <module name="IllegalImport"/> <!-- defaults to sun.* packages -->
+    <module name="RedundantImport"/>
+    <module name="UnusedImports">
+      <property name="processJavadoc" value="false"/>
+    </module>
+
+    <!-- Checks for Size Violations.                    -->
+    <!-- See https://checkstyle.org/checks/sizes/index.html -->
+    <module name="MethodLength"/>
+    <module name="ParameterNumber"/>
+
+    <!-- Checks for whitespace                               -->
+    <!-- See https://checkstyle.org/checks/whitespace/index.html -->
+    <module name="EmptyForIteratorPad"/>
+    <!-- TODO <module name="GenericWhitespace"/> -->
+    <module name="MethodParamPad"/>
+    <!-- TODO <module name="NoWhitespaceAfter"/> -->
+    <module name="NoWhitespaceBefore"/>
+    <!-- TODO <module name="OperatorWrap"/> -->
+    <!-- TODO <module name="ParenPad"/> -->
+    <module name="TypecastParenPad"/>
+    <module name="WhitespaceAfter"/>
+    <!-- TODO <module name="WhitespaceAround"/> -->
+
+    <!-- Modifier Checks                                    -->
+    <!-- See https://checkstyle.org/checks/modifier/index.html -->
+    <!-- TODO <module name="ModifierOrder"/> -->
+    <!-- TODO <module name="RedundantModifier"/> -->
+
+    <!-- Checks for blocks. You know, those {}'s         -->
+    <!-- See https://checkstyle.org/checks/blocks/index.html -->
+    <!-- TODO <module name="AvoidNestedBlocks"/> -->
+    <!-- TODO <module name="EmptyBlock"/> -->
+    <!-- TODO <module name="LeftCurly"/> -->
+    <!-- TODO <module name="NeedBraces"/> -->
+    <!-- TODO <module name="RightCurly"/> -->
+
+    <!-- Checks for common coding problems               -->
+    <!-- See https://checkstyle.org/checks/coding/index.html -->
+    <!-- <module name="EmptyStatement"/> -->
+    <!-- TODO <module name="EqualsHashCode"/> -->
+    <!-- TODO <module name="HiddenField"/> -->
+    <module name="IllegalInstantiation"/>
+    <!-- TODO <module name="InnerAssignment"/> -->
+    <!-- TODO <module name="MagicNumber"/> -->
+    <!-- TODO <module name="MissingSwitchDefault"/> -->
+    <!-- TODO <module name="MultipleVariableDeclarations"/> -->
+    <module name="SimplifyBooleanExpression"/>
+    <module name="SimplifyBooleanReturn"/>
+
+    <!-- Checks for class design                         -->
+    <!-- See https://checkstyle.org/checks/design/index.html -->
+    <!-- TODO <module name="DesignForExtension"/> -->
+    <!-- TODO <module name="FinalClass"/> -->
+    <!-- TODO <module name="HideUtilityClassConstructor"/> -->
+    <module name="InterfaceIsType"/>
+    <!-- TODO <module name="VisibilityModifier"/> -->
+
+    <!-- Miscellaneous other checks.                   -->
+    <!-- See https://checkstyle.org/checks/misc/index.html -->
+    <!-- TODO <module name="ArrayTypeStyle"/> -->
+    <!-- TODO <module name="FinalParameters"/> -->
+    <!-- TODO <module name="TodoComment"/> -->
+    <module name="UpperEll"/>
+
+    <!-- https://checkstyle.org/filters/suppressionxpathfilter.html -->
+    <module name="SuppressionXpathFilter">
+      <property name="file" value="${org.checkstyle.sun.suppressionxpathfilter.config}"
+                default="checkstyle-xpath-suppressions.xml" />
+      <property name="optional" value="true"/>
+    </module>
+
+  </module>
+
+</module>
diff --git a/pom.xml b/pom.xml
index f81894dcaf7e..594a9acc39f1 100644
--- a/pom.xml
+++ b/pom.xml
@@ -96,6 +96,24 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-checkstyle-plugin</artifactId>
+                <version>3.3.1</version>
+                <configuration>
+                    <configLocation>checkstyle.xml</configLocation>
+                    <consoleOutput>true</consoleOutput>
+                    <includeTestSourceDirectory>true</includeTestSourceDirectory>
+                    <violationSeverity>warning</violationSeverity>
+                </configuration>
+                <dependencies>
+                    <dependency>
+                    <groupId>com.puppycrawl.tools</groupId>
+                    <artifactId>checkstyle</artifactId>
+                    <version>9.3</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
         </plugins>
     </build>
 </project>

From 6de154d218a54186dfc8efefc45aab862b086aee Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 26 Apr 2024 08:40:01 +0200
Subject: [PATCH 0126/1338] tests: add tests of `Mode` (#5104)

---
 .../java/com/thealgorithms/maths/Mode.java    | 14 +++----------
 .../com/thealgorithms/maths/ModeTest.java     | 21 +++++++++++++++++++
 2 files changed, 24 insertions(+), 11 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/ModeTest.java

diff --git a/src/main/java/com/thealgorithms/maths/Mode.java b/src/main/java/com/thealgorithms/maths/Mode.java
index 7333380b0a69..a92f404c653a 100644
--- a/src/main/java/com/thealgorithms/maths/Mode.java
+++ b/src/main/java/com/thealgorithms/maths/Mode.java
@@ -1,7 +1,6 @@
 package com.thealgorithms.maths;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 
@@ -11,15 +10,8 @@
  * The mode of an array of numbers is the most frequently occurring number in the array,
  * or the most frequently occurring numbers if there are multiple numbers with the same frequency
  */
-public class Mode {
-
-    public static void main(String[] args) {
-        /* Test array of integers */
-        assert (mode(new int[] {})) == null;
-        assert Arrays.equals(mode(new int[] {5}), new int[] {5});
-        assert Arrays.equals(mode(new int[] {1, 2, 3, 4, 5}), new int[] {1, 2, 3, 4, 5});
-        assert Arrays.equals(mode(new int[] {7, 9, 9, 4, 5, 6, 7, 7, 8}), new int[] {7});
-        assert Arrays.equals(mode(new int[] {7, 9, 9, 4, 5, 6, 7, 7, 9}), new int[] {7, 9});
+public final class Mode {
+    private Mode() {
     }
 
     /*
@@ -28,7 +20,7 @@ public static void main(String[] args) {
      * @param numbers array of integers
      * @return mode of the array
      */
-    public static int[] mode(int[] numbers) {
+    public static int[] mode(final int[] numbers) {
         if (numbers.length == 0) {
             return null;
         }
diff --git a/src/test/java/com/thealgorithms/maths/ModeTest.java b/src/test/java/com/thealgorithms/maths/ModeTest.java
new file mode 100644
index 000000000000..629fd8bd580a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/ModeTest.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class ModeTest {
+    @ParameterizedTest
+    @MethodSource("tcStream")
+    void basicTest(final int[] expected, final int[] numbers) {
+        assertArrayEquals(expected, Mode.mode(numbers));
+    }
+
+    private static Stream<Arguments> tcStream() {
+        return Stream.of(Arguments.of(null, new int[] {}), Arguments.of(new int[] {5}, new int[] {5}), Arguments.of(new int[] {1, 2, 3, 4, 5}, new int[] {1, 2, 3, 4, 5}), Arguments.of(new int[] {1, 2, 3, 4, 5}, new int[] {5, 4, 3, 2, 1}),
+            Arguments.of(new int[] {7}, new int[] {7, 9, 9, 4, 5, 6, 7, 7, 8}), Arguments.of(new int[] {7, 9}, new int[] {7, 9, 9, 4, 5, 6, 7, 7, 9}));
+    }
+}

From de18d0df7e5d807e01971747f2613726e5cd0e1f Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 26 Apr 2024 21:39:03 +0200
Subject: [PATCH 0127/1338] style: enable `EmptyStatement` (#5120)

---
 checkstyle.xml                                        | 2 +-
 src/main/java/com/thealgorithms/sorts/CircleSort.java | 4 ++--
 src/test/java/com/thealgorithms/ciphers/DESTest.java  | 1 -
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 6f635c7af61d..e4764fb1cc8a 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -160,7 +160,7 @@
 
     <!-- Checks for common coding problems               -->
     <!-- See https://checkstyle.org/checks/coding/index.html -->
-    <!-- <module name="EmptyStatement"/> -->
+    <module name="EmptyStatement"/>
     <!-- TODO <module name="EqualsHashCode"/> -->
     <!-- TODO <module name="HiddenField"/> -->
     <module name="IllegalInstantiation"/>
diff --git a/src/main/java/com/thealgorithms/sorts/CircleSort.java b/src/main/java/com/thealgorithms/sorts/CircleSort.java
index 74b3fc62125d..7f2dc5fdfef5 100644
--- a/src/main/java/com/thealgorithms/sorts/CircleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CircleSort.java
@@ -10,8 +10,8 @@ public class CircleSort implements SortAlgorithm {
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
         int n = array.length;
-        while (doSort(array, 0, n - 1))
-            ;
+        while (doSort(array, 0, n - 1)) {
+        }
         return array;
     }
 
diff --git a/src/test/java/com/thealgorithms/ciphers/DESTest.java b/src/test/java/com/thealgorithms/ciphers/DESTest.java
index e652c028d5dd..834f7e195165 100644
--- a/src/test/java/com/thealgorithms/ciphers/DESTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/DESTest.java
@@ -45,7 +45,6 @@ void testDecrypt() {
             + "001101001101001001101011001000011100000011001000011011001110101010010111101111000111"
             + "101010011010110000100100110011000001010001010110010011011010001010011111000001110011001010011";
         String expectedOutput = "Your lips are smoother than vaseline\r\n";
-        ;
 
         // when
         String plainText = des.decrypt(cipherText);

From 4bb64559deb6722069678aaa910f7379645d5a7b Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 28 Apr 2024 10:31:11 +0200
Subject: [PATCH 0128/1338] chore: configure SpotBugs (#5122)

---
 .github/workflows/build.yml |   2 +
 pom.xml                     |   9 +++
 spotbugs-exclude.xml        | 134 ++++++++++++++++++++++++++++++++++++
 3 files changed, 145 insertions(+)
 create mode 100644 spotbugs-exclude.xml

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 49821b917fd2..39a690f9aec4 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -31,3 +31,5 @@ jobs:
           fail_ci_if_error: true
       - name: Checkstyle
         run: mvn checkstyle:check
+      - name: SpotBugs
+        run: mvn spotbugs:check
diff --git a/pom.xml b/pom.xml
index 594a9acc39f1..b9c2e64888d1 100644
--- a/pom.xml
+++ b/pom.xml
@@ -114,6 +114,15 @@
                     </dependency>
                 </dependencies>
             </plugin>
+            <plugin>
+                <groupId>com.github.spotbugs</groupId>
+                <artifactId>spotbugs-maven-plugin</artifactId>
+                <version>4.8.4.0</version>
+                <configuration>
+                    <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
+                    <includeTests>true</includeTests>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 </project>
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
new file mode 100644
index 000000000000..959773494617
--- /dev/null
+++ b/spotbugs-exclude.xml
@@ -0,0 +1,134 @@
+<FindBugsFilter>
+    <Match>
+        <Bug pattern="DM_DEFAULT_ENCODING" />
+    </Match>
+    <Match>
+        <Bug pattern="EI_EXPOSE_REP2" />
+    </Match>
+    <Match>
+        <Bug pattern="ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD" />
+    </Match>
+    <Match>
+        <Bug pattern="IM_AVERAGE_COMPUTATION_COULD_OVERFLOW" />
+    </Match>
+    <Match>
+        <Bug pattern="DMI_RANDOM_USED_ONLY_ONCE" />
+    </Match>
+    <Match>
+        <Bug pattern="VA_FORMAT_STRING_USES_NEWLINE" />
+    </Match>
+    <Match>
+        <Bug pattern="SF_SWITCH_NO_DEFAULT" />
+    </Match>
+    <Match>
+        <Bug pattern="UC_USELESS_OBJECT" />
+    </Match>
+    <Match>
+        <Bug pattern="RV_RETURN_VALUE_IGNORED_NO_SIDE_EFFECT" />
+    </Match>
+    <Match>
+        <Bug pattern="DM_NEXTINT_VIA_NEXTDOUBLE" />
+    </Match>
+    <Match>
+        <Bug pattern="NM_CLASS_NAMING_CONVENTION" />
+    </Match>
+    <Match>
+        <Bug pattern="SIC_INNER_SHOULD_BE_STATIC" />
+    </Match>
+    <Match>
+        <Bug pattern="EI_EXPOSE_REP" />
+    </Match>
+    <Match>
+        <Bug pattern="EI_EXPOSE_REP" />
+    </Match>
+    <Match>
+        <Bug pattern="SBSC_USE_STRINGBUFFER_CONCATENATION" />
+    </Match>
+    <Match>
+        <Bug pattern="PA_PUBLIC_PRIMITIVE_ATTRIBUTE" />
+    </Match>
+    <Match>
+        <Bug pattern="MS_PKGPROTECT" />
+    </Match>
+    <Match>
+        <Bug pattern="SE_COMPARATOR_SHOULD_BE_SERIALIZABLE" />
+    </Match>
+    <Match>
+        <Bug pattern="INT_BAD_REM_BY_1" />
+    </Match>
+    <Match>
+        <Bug pattern="NM_METHOD_NAMING_CONVENTION" />
+    </Match>
+    <Match>
+        <Bug pattern="ICAST_IDIV_CAST_TO_DOUBLE" />
+    </Match>
+    <Match>
+        <Bug pattern="FE_FLOATING_POINT_EQUALITY" />
+    </Match>
+    <Match>
+        <Bug pattern="CT_CONSTRUCTOR_THROW" />
+    </Match>
+    <Match>
+        <Bug pattern="URF_UNREAD_FIELD" />
+    </Match>
+    <Match>
+        <Bug pattern="RC_REF_COMPARISON" />
+    </Match>
+    <Match>
+        <Bug pattern="MS_EXPOSE_REP" />
+    </Match>
+    <Match>
+        <Bug pattern="IM_BAD_CHECK_FOR_ODD" />
+    </Match>
+    <Match>
+        <Bug pattern="WMI_WRONG_MAP_ITERATOR" />
+    </Match>
+    <Match>
+        <Bug pattern="DM_BOXED_PRIMITIVE_FOR_PARSING" />
+    </Match>
+    <Match>
+        <Bug pattern="MS_SHOULD_BE_FINAL" />
+    </Match>
+    <Match>
+        <Bug pattern="UWF_UNWRITTEN_FIELD" />
+    </Match>
+    <Match>
+        <Bug pattern="SS_SHOULD_BE_STATIC" />
+    </Match>
+    <Match>
+        <Bug pattern="HE_EQUALS_USE_HASHCODE" />
+    </Match>
+    <Match>
+        <Bug pattern="IT_NO_SUCH_ELEMENT" />
+    </Match>
+    <Match>
+        <Bug pattern="DLS_DEAD_LOCAL_STORE" />
+    </Match>
+    <Match>
+        <Bug pattern="UWF_NULL_FIELD" />
+    </Match>
+    <Match>
+        <Bug pattern="NP_UNWRITTEN_FIELD" />
+    </Match>
+    <Match>
+        <Bug pattern="URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD" />
+    </Match>
+    <Match>
+        <Bug pattern="NP_IMMEDIATE_DEREFERENCE_OF_READLINE" />
+    </Match>
+    <Match>
+        <Bug pattern="RV_RETURN_VALUE_IGNORED" />
+    </Match>
+    <Match>
+        <Bug pattern="EQ_COMPARETO_USE_OBJECT_EQUALS" />
+    </Match>
+    <Match>
+        <Bug pattern="SA_FIELD_SELF_ASSIGNMENT" />
+    </Match>
+    <Match>
+        <Bug pattern="RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE" />
+    </Match>
+    <Match>
+        <Bug pattern="RV_ABSOLUTE_VALUE_OF_HASHCODE" />
+    </Match>
+</FindBugsFilter>

From b075c19a548e7e1645f5024957cdec58e3dd577b Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 30 Apr 2024 08:34:07 +0200
Subject: [PATCH 0129/1338] Chore(deps): bump gitpod/workspace-java-17 from
 2024-04-16-12-16-24 to 2024-04-29-07-29-58 (#5130)

Chore(deps): bump gitpod/workspace-java-17

Bumps gitpod/workspace-java-17 from 2024-04-16-12-16-24 to 2024-04-29-07-29-58.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-17
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 89a19f3627cf..078fa3800abd 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-17:2024-04-16-12-16-24
+FROM gitpod/workspace-java-17:2024-04-29-07-29-58
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 2513ccd62b2420c98a32f315c982c17543367fe4 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 1 May 2024 11:58:04 +0200
Subject: [PATCH 0130/1338] style: include
 `IM_AVERAGE_COMPUTATION_COULD_OVERFLOW` (#5131)

---
 spotbugs-exclude.xml                                        | 3 ---
 .../dynamicprogramming/LongestIncreasingSubsequence.java    | 2 +-
 .../java/com/thealgorithms/misc/RangeInSortedArray.java     | 6 +++---
 .../java/com/thealgorithms/sorts/BinaryInsertionSort.java   | 2 +-
 src/main/java/com/thealgorithms/sorts/SlowSort.java         | 2 +-
 5 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 959773494617..dd9d267b2005 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -8,9 +8,6 @@
     <Match>
         <Bug pattern="ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD" />
     </Match>
-    <Match>
-        <Bug pattern="IM_AVERAGE_COMPUTATION_COULD_OVERFLOW" />
-    </Match>
     <Match>
         <Bug pattern="DMI_RANDOM_USED_ONLY_ONCE" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
index e7a54f213ac1..a0882007dfbd 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
@@ -97,7 +97,7 @@ private static int binarySearchBetween(int[] t, int end, int key) {
             return end + 1;
         }
         while (left < right - 1) {
-            int middle = (left + right) / 2;
+            final int middle = (left + right) >>> 1;
             if (t[middle] < key) {
                 left = middle;
             } else {
diff --git a/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java b/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
index af2ca4dd5324..d0d543d33966 100644
--- a/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
+++ b/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
@@ -26,7 +26,7 @@ public static void alteredBinSearch(int[] nums, int key, int left, int right, in
         if (left > right) {
             return;
         }
-        int mid = (left + right) / 2;
+        int mid = (left + right) >>> 1;
         if (nums[mid] > key) {
             alteredBinSearch(nums, key, left, mid - 1, range, goLeft);
         } else if (nums[mid] < key) {
@@ -52,7 +52,7 @@ public static void alteredBinSearch(int[] nums, int key, int left, int right, in
     // of 'key'
     public static void alteredBinSearchIter(int[] nums, int key, int left, int right, int[] range, boolean goLeft) {
         while (left <= right) {
-            int mid = (left + right) / 2;
+            final int mid = (left + right) >>> 1;
             if (nums[mid] > key) {
                 right = mid - 1;
             } else if (nums[mid] < key) {
@@ -84,7 +84,7 @@ public static int getCountLessThan(int[] nums, int key) {
     public static int getLessThan(int[] nums, int key, int left, int right) {
         int count = 0;
         while (left <= right) {
-            int mid = (left + right) / 2;
+            final int mid = (left + right) >>> 1;
             if (nums[mid] > key) {
                 right = mid - 1;
             } else if (nums[mid] <= key) {
diff --git a/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java b/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java
index 1c2dce65c953..13076c617c76 100644
--- a/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java
@@ -10,7 +10,7 @@ public int[] binaryInsertSort(int[] array) {
             int high = i - 1;
 
             while (low <= high) {
-                int mid = (low + high) / 2;
+                final int mid = (low + high) >>> 1;
                 if (temp < array[mid]) {
                     high = mid - 1;
                 } else {
diff --git a/src/main/java/com/thealgorithms/sorts/SlowSort.java b/src/main/java/com/thealgorithms/sorts/SlowSort.java
index 1ab8ceea4fdf..dcd426b31c0d 100644
--- a/src/main/java/com/thealgorithms/sorts/SlowSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SlowSort.java
@@ -16,7 +16,7 @@ private <T extends Comparable<T>> void sort(T[] array, int i, int j) {
         if (SortUtils.greaterOrEqual(i, j)) {
             return;
         }
-        int m = (i + j) / 2;
+        final int m = (i + j) >>> 1;
         sort(array, i, m);
         sort(array, m + 1, j);
         if (SortUtils.less(array[j], array[m])) {

From fd658924159e95b8cad3005f9ac5f7748eb7e682 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 1 May 2024 12:56:47 +0200
Subject: [PATCH 0131/1338] chore: add `maven` to dependabot (#5123)

---
 .github/dependabot.yml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index e568006bd634..2e5622f7b51d 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -10,4 +10,9 @@ updates:
     directory: "/.github/workflows/"
     schedule:
       interval: "daily"
+
+  - package-ecosystem: "maven"
+    directory: "/"
+    schedule:
+      interval: "daily"
 ...

From 06a284f811204438c914dc9faf23278734cdfe55 Mon Sep 17 00:00:00 2001
From: marysiuniq <67139391+marysiuniq@users.noreply.github.com>
Date: Wed, 1 May 2024 13:06:19 +0200
Subject: [PATCH 0132/1338] style: enable `ModifierOrder` in checkstyle (#5132)

* style: enable `ModifierOrder` in checkstyle

* style: remove redundant `final`

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

---------

Co-authored-by: Maria Paszkiewicz SCC <maria.paszkiewicz@kit.edu>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 checkstyle.xml                                                  | 2 +-
 .../java/com/thealgorithms/bitmanipulation/HighestSetBit.java   | 2 +-
 src/main/java/com/thealgorithms/others/CountWords.java          | 2 +-
 src/main/java/com/thealgorithms/others/EulersFunction.java      | 2 +-
 .../java/com/thealgorithms/others/LowestBasePalindrome.java     | 2 +-
 src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java | 2 +-
 src/main/java/com/thealgorithms/others/cn/HammingDistance.java  | 2 +-
 7 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index e4764fb1cc8a..d16549b6494b 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -147,7 +147,7 @@
 
     <!-- Modifier Checks                                    -->
     <!-- See https://checkstyle.org/checks/modifier/index.html -->
-    <!-- TODO <module name="ModifierOrder"/> -->
+    <module name="ModifierOrder"/>
     <!-- TODO <module name="RedundantModifier"/> -->
 
     <!-- Checks for blocks. You know, those {}'s         -->
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java b/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java
index 398b6bbb67bb..6b53b1aa182b 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java
@@ -12,7 +12,7 @@ public final class HighestSetBit {
     private HighestSetBit() {
     }
 
-    public final static Optional<Integer> findHighestSetBit(int num) {
+    public static Optional<Integer> findHighestSetBit(int num) {
         if (num < 0) {
             throw new IllegalArgumentException("Input cannot be negative");
         }
diff --git a/src/main/java/com/thealgorithms/others/CountWords.java b/src/main/java/com/thealgorithms/others/CountWords.java
index 1defde2cdd8b..26b9c50d928c 100644
--- a/src/main/java/com/thealgorithms/others/CountWords.java
+++ b/src/main/java/com/thealgorithms/others/CountWords.java
@@ -3,7 +3,7 @@
 /**
  * @author Marcus
  */
-final public class CountWords {
+public final class CountWords {
     private CountWords() {
     }
 
diff --git a/src/main/java/com/thealgorithms/others/EulersFunction.java b/src/main/java/com/thealgorithms/others/EulersFunction.java
index 27c9aed8b620..f08e5e4fa395 100644
--- a/src/main/java/com/thealgorithms/others/EulersFunction.java
+++ b/src/main/java/com/thealgorithms/others/EulersFunction.java
@@ -3,7 +3,7 @@
 /**
  * @brief utility class for <a href="https://en.wikipedia.org/wiki/Euler%27s_totient_function">Euler's totient function</a>
  */
-final public class EulersFunction {
+public final class EulersFunction {
     private EulersFunction() {
     }
 
diff --git a/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java b/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
index 9bc02535a306..c8328a4ee552 100644
--- a/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
+++ b/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
@@ -6,7 +6,7 @@
  * @brief Class for finding the lowest base in which a given integer is a palindrome.
      cf. https://oeis.org/A016026
  */
-final public class LowestBasePalindrome {
+public final class LowestBasePalindrome {
     private LowestBasePalindrome() {
     }
 
diff --git a/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java b/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java
index d7dcdbd11493..1fd9ae288920 100644
--- a/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java
+++ b/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java
@@ -5,7 +5,7 @@
 /**
  * @brief utility class implementing <a href="https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes">Sieve of Eratosthenes</a>
  */
-final public class SieveOfEratosthenes {
+public final class SieveOfEratosthenes {
     private SieveOfEratosthenes() {
     }
 
diff --git a/src/main/java/com/thealgorithms/others/cn/HammingDistance.java b/src/main/java/com/thealgorithms/others/cn/HammingDistance.java
index 820917a17229..c8239d53d606 100644
--- a/src/main/java/com/thealgorithms/others/cn/HammingDistance.java
+++ b/src/main/java/com/thealgorithms/others/cn/HammingDistance.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others.cn;
 
-final public class HammingDistance {
+public final class HammingDistance {
     private HammingDistance() {
     }
 

From f64bc3c65d4c7b6465a7ff0d1623e7437a44da55 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 1 May 2024 13:11:03 +0200
Subject: [PATCH 0133/1338] style: include `UC_USELESS_OBJECT` (#5127)

---
 spotbugs-exclude.xml                                     | 3 ---
 .../java/com/thealgorithms/sorts/MergeSortRecursive.java | 9 ---------
 2 files changed, 12 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index dd9d267b2005..799a72fa91cf 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -17,9 +17,6 @@
     <Match>
         <Bug pattern="SF_SWITCH_NO_DEFAULT" />
     </Match>
-    <Match>
-        <Bug pattern="UC_USELESS_OBJECT" />
-    </Match>
     <Match>
         <Bug pattern="RV_RETURN_VALUE_IGNORED_NO_SIDE_EFFECT" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java b/src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java
index f9d12a2aae38..f67ba631be0e 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java
@@ -1,7 +1,6 @@
 package com.thealgorithms.sorts;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.List;
 
 public class MergeSortRecursive {
@@ -59,11 +58,3 @@ private static List<Integer> sort(List<Integer> unsortedA, List<Integer> unsorte
         }
     }
 }
-
-class App {
-
-    public static void main(String[] args) {
-        MergeSortRecursive sort = new MergeSortRecursive(new ArrayList<>(Arrays.asList(4, 3, 1, 8, 5, 10, 0, 1, 4, 11, 8, 9)));
-        sort.mergeSort();
-    }
-}

From cdc320afafbb00bea20dc47ec927b977f0b78063 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 1 May 2024 14:46:48 +0000
Subject: [PATCH 0134/1338] Chore(deps): bump com.puppycrawl.tools:checkstyle
 from 9.3 to 10.16.0 (#5134)

* Chore(deps): bump com.puppycrawl.tools:checkstyle from 9.3 to 10.16.0

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 9.3 to 10.16.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-9.3...checkstyle-10.16.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

* Update directory

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: dependabot[bot] <dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b9c2e64888d1..9111d7b49a30 100644
--- a/pom.xml
+++ b/pom.xml
@@ -110,7 +110,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>9.3</version>
+                    <version>10.16.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 032c28892232d6af4e9291d4b8645b5fedd6c394 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 1 May 2024 16:51:39 +0200
Subject: [PATCH 0135/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-compiler-plugin from 3.10.1 to 3.13.0 (#5135)

Chore(deps): bump org.apache.maven.plugins:maven-compiler-plugin

Bumps [org.apache.maven.plugins:maven-compiler-plugin](https://github.com/apache/maven-compiler-plugin) from 3.10.1 to 3.13.0.
- [Release notes](https://github.com/apache/maven-compiler-plugin/releases)
- [Commits](https://github.com/apache/maven-compiler-plugin/compare/maven-compiler-plugin-3.10.1...maven-compiler-plugin-3.13.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-compiler-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 9111d7b49a30..b823f9e3563b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -71,7 +71,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.10.1</version>
+                <version>3.13.0</version>
                 <configuration>
                     <source>17</source>
                     <target>17</target>

From ede3e4651f5443092427f6fdd12bf5bedcb5db0c Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 2 May 2024 08:20:13 +0200
Subject: [PATCH 0136/1338] Chore(deps): bump gitpod/workspace-java-17 from
 2024-04-29-07-29-58 to 2024-04-29-23-03-42 (#5133)

Chore(deps): bump gitpod/workspace-java-17

Bumps gitpod/workspace-java-17 from 2024-04-29-07-29-58 to 2024-04-29-23-03-42.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-17
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 078fa3800abd..07b853b087de 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-17:2024-04-29-07-29-58
+FROM gitpod/workspace-java-17:2024-04-29-23-03-42
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 1e2d7e943146d25f97aa3ad516f8794b5ce0fd7d Mon Sep 17 00:00:00 2001
From: marysiuniq <67139391+marysiuniq@users.noreply.github.com>
Date: Thu, 2 May 2024 18:31:37 +0200
Subject: [PATCH 0137/1338] style: enable `ConstantName` in checkstyle (#5139)

Co-authored-by: Maria Paszkiewicz SCC <maria.paszkiewicz@kit.edu>
---
 checkstyle.xml                                |  2 +-
 .../backtracking/KnightsTour.java             | 22 +++++++++----------
 .../com/thealgorithms/ciphers/Polybius.java   | 10 ++++-----
 .../conversions/DecimalToHexaDecimal.java     | 20 ++++++++---------
 .../conversions/IntegerToRoman.java           | 12 +++++-----
 .../conversions/RomanToInteger.java           |  8 +++----
 .../datastructures/trees/LCA.java             | 10 ++++-----
 .../dynamicprogramming/Fibonacci.java         |  8 +++----
 .../MatrixChainMultiplication.java            | 14 ++++++------
 .../thealgorithms/maths/FindKthNumber.java    |  6 ++---
 .../matrixexponentiation/Fibonacci.java       | 12 +++++-----
 .../java/com/thealgorithms/others/Conway.java |  8 +++----
 .../com/thealgorithms/others/RabinKarp.java   | 18 +++++++--------
 .../searches/RabinKarpAlgorithm.java          | 11 +++++-----
 .../com/thealgorithms/sorts/BogoSort.java     |  4 ++--
 .../sorts/SortUtilsRandomGenerator.java       | 12 +++++-----
 16 files changed, 87 insertions(+), 90 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index d16549b6494b..78ca487a414e 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -108,7 +108,7 @@
 
     <!-- Checks for Naming Conventions.                  -->
     <!-- See https://checkstyle.org/checks/naming/index.html -->
-    <!-- TODO <module name="ConstantName"/> -->
+    <module name="ConstantName"/>
     <!-- TODO <module name="LocalFinalVariableName"/> -->
     <!-- TODO <module name="LocalVariableName"/> -->
     <!-- TODO <module name="MemberName"/> -->
diff --git a/src/main/java/com/thealgorithms/backtracking/KnightsTour.java b/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
index 27b7f66c1f63..6b3ec78a435a 100644
--- a/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
+++ b/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
@@ -26,8 +26,8 @@
  */
 public class KnightsTour {
 
-    private static final int base = 12;
-    private static final int[][] moves = {
+    private static final int BASE = 12;
+    private static final int[][] MOVES = {
         {1, -2},
         {2, -1},
         {2, 1},
@@ -41,19 +41,19 @@ public class KnightsTour {
     private static int total; // total squares in chess
 
     public static void main(String[] args) {
-        grid = new int[base][base];
-        total = (base - 4) * (base - 4);
+        grid = new int[BASE][BASE];
+        total = (BASE - 4) * (BASE - 4);
 
-        for (int r = 0; r < base; r++) {
-            for (int c = 0; c < base; c++) {
-                if (r < 2 || r > base - 3 || c < 2 || c > base - 3) {
+        for (int r = 0; r < BASE; r++) {
+            for (int c = 0; c < BASE; c++) {
+                if (r < 2 || r > BASE - 3 || c < 2 || c > BASE - 3) {
                     grid[r][c] = -1;
                 }
             }
         }
 
-        int row = 2 + (int) (Math.random() * (base - 4));
-        int col = 2 + (int) (Math.random() * (base - 4));
+        int row = 2 + (int) (Math.random() * (BASE - 4));
+        int col = 2 + (int) (Math.random() * (BASE - 4));
 
         grid[row][col] = 1;
 
@@ -95,7 +95,7 @@ private static boolean solve(int row, int column, int count) {
     private static List<int[]> neighbors(int row, int column) {
         List<int[]> neighbour = new ArrayList<>();
 
-        for (int[] m : moves) {
+        for (int[] m : MOVES) {
             int x = m[0];
             int y = m[1];
             if (grid[row + y][column + x] == 0) {
@@ -109,7 +109,7 @@ private static List<int[]> neighbors(int row, int column) {
     // Returns the total count of neighbors
     private static int countNeighbors(int row, int column) {
         int num = 0;
-        for (int[] m : moves) {
+        for (int[] m : MOVES) {
             if (grid[row + m[1]][column + m[0]] == 0) {
                 num++;
             }
diff --git a/src/main/java/com/thealgorithms/ciphers/Polybius.java b/src/main/java/com/thealgorithms/ciphers/Polybius.java
index 7b5a27807bc4..b28cac8a586e 100644
--- a/src/main/java/com/thealgorithms/ciphers/Polybius.java
+++ b/src/main/java/com/thealgorithms/ciphers/Polybius.java
@@ -15,7 +15,7 @@
  */
 public class Polybius {
 
-    private static final char[][] key = {
+    private static final char[][] KEY = {
         //         0    1    2    3    4
         /* 0 */ {'A', 'B', 'C', 'D', 'E'},
         /* 1 */ {'F', 'G', 'H', 'I', 'J'},
@@ -26,9 +26,9 @@ public class Polybius {
 
     private static String findLocationByCharacter(final char character) {
         final StringBuilder location = new StringBuilder();
-        for (int i = 0; i < key.length; i++) {
-            for (int j = 0; j < key[i].length; j++) {
-                if (character == key[i][j]) {
+        for (int i = 0; i < KEY.length; i++) {
+            for (int j = 0; j < KEY[i].length; j++) {
+                if (character == KEY[i][j]) {
                     location.append(i).append(j);
                     break;
                 }
@@ -53,7 +53,7 @@ public static String decrypt(final String ciphertext) {
         for (int i = 0; i < chars.length; i += 2) {
             int pozitionX = Character.getNumericValue(chars[i]);
             int pozitionY = Character.getNumericValue(chars[i + 1]);
-            plaintext.append(key[pozitionX][pozitionY]);
+            plaintext.append(KEY[pozitionX][pozitionY]);
         }
         return plaintext.toString();
     }
diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java b/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java
index 3564acbe568c..1435c7f8b5fa 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java
@@ -3,10 +3,10 @@
 // hex = [0 - 9] -> [A - F]
 class DecimalToHexaDecimal {
 
-    private static final int sizeOfIntInHalfBytes = 8;
-    private static final int numberOfBitsInAHalfByte = 4;
-    private static final int halfByte = 0x0F;
-    private static final char[] hexDigits = {
+    private static final int SIZE_OF_INT_IN_HALF_BYTES = 8;
+    private static final int NUMBER_OF_BITS_IN_HALF_BYTE = 4;
+    private static final int HALF_BYTE = 0x0F;
+    private static final char[] HEX_DIGITS = {
         '0',
         '1',
         '2',
@@ -27,12 +27,12 @@ class DecimalToHexaDecimal {
 
     // Returns the hex value of the dec entered in the parameter.
     public static String decToHex(int dec) {
-        StringBuilder hexBuilder = new StringBuilder(sizeOfIntInHalfBytes);
-        hexBuilder.setLength(sizeOfIntInHalfBytes);
-        for (int i = sizeOfIntInHalfBytes - 1; i >= 0; --i) {
-            int j = dec & halfByte;
-            hexBuilder.setCharAt(i, hexDigits[j]);
-            dec >>= numberOfBitsInAHalfByte;
+        StringBuilder hexBuilder = new StringBuilder(SIZE_OF_INT_IN_HALF_BYTES);
+        hexBuilder.setLength(SIZE_OF_INT_IN_HALF_BYTES);
+        for (int i = SIZE_OF_INT_IN_HALF_BYTES - 1; i >= 0; --i) {
+            int j = dec & HALF_BYTE;
+            hexBuilder.setCharAt(i, HEX_DIGITS[j]);
+            dec >>= NUMBER_OF_BITS_IN_HALF_BYTE;
         }
         return hexBuilder.toString().toLowerCase();
     }
diff --git a/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java b/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
index aae0b3b29376..5507ab1169af 100644
--- a/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
+++ b/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
@@ -9,7 +9,7 @@
  */
 public class IntegerToRoman {
 
-    private static final int[] allArabianRomanNumbers = new int[] {
+    private static final int[] ALL_ROMAN_NUMBERS_IN_ARABIC = new int[] {
         1000,
         900,
         500,
@@ -24,7 +24,7 @@ public class IntegerToRoman {
         4,
         1,
     };
-    private static final String[] allRomanNumbers = new String[] {
+    private static final String[] ALL_ROMAN_NUMBERS = new String[] {
         "M",
         "CM",
         "D",
@@ -48,13 +48,13 @@ public static String integerToRoman(int num) {
 
         StringBuilder builder = new StringBuilder();
 
-        for (int a = 0; a < allArabianRomanNumbers.length; a++) {
-            int times = num / allArabianRomanNumbers[a];
+        for (int a = 0; a < ALL_ROMAN_NUMBERS_IN_ARABIC.length; a++) {
+            int times = num / ALL_ROMAN_NUMBERS_IN_ARABIC[a];
             for (int b = 0; b < times; b++) {
-                builder.append(allRomanNumbers[a]);
+                builder.append(ALL_ROMAN_NUMBERS[a]);
             }
 
-            num -= times * allArabianRomanNumbers[a];
+            num -= times * ALL_ROMAN_NUMBERS_IN_ARABIC[a];
         }
 
         return builder.toString();
diff --git a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
index d5dc79872a67..19535df72d67 100644
--- a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
+++ b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
@@ -4,9 +4,7 @@
 
 public class RomanToInteger {
 
-    private static final Map<Character, Integer> map = new HashMap<>() {
-        private static final long serialVersionUID = 87605733047260530L;
-
+    private static final Map<Character, Integer> ROMAN_TO_INT = new HashMap<>() {
         {
             put('I', 1);
             put('V', 5);
@@ -38,10 +36,10 @@ public static int romanToInt(String A) {
 
             if (prev != ' ') {
                 // checking current Number greater then previous or not
-                newPrev = map.get(prev) > newPrev ? map.get(prev) : newPrev;
+                newPrev = ROMAN_TO_INT.get(prev) > newPrev ? ROMAN_TO_INT.get(prev) : newPrev;
             }
 
-            int currentNum = map.get(c);
+            int currentNum = ROMAN_TO_INT.get(c);
 
             // if current number greater then prev max previous then add
             if (currentNum >= newPrev) {
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/LCA.java b/src/main/java/com/thealgorithms/datastructures/trees/LCA.java
index d45f0d4f4301..c8bac470d9b7 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/LCA.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/LCA.java
@@ -5,14 +5,14 @@
 
 public class LCA {
 
-    private static final Scanner scanner = new Scanner(System.in);
+    private static final Scanner SCANNER = new Scanner(System.in);
 
     public static void main(String[] args) {
         // The adjacency list representation of a tree:
         ArrayList<ArrayList<Integer>> adj = new ArrayList<>();
 
         // v is the number of vertices and e is the number of edges
-        int v = scanner.nextInt(), e = v - 1;
+        int v = SCANNER.nextInt(), e = v - 1;
 
         for (int i = 0; i < v; i++) {
             adj.add(new ArrayList<Integer>());
@@ -21,8 +21,8 @@ public static void main(String[] args) {
         // Storing the given tree as an adjacency list
         int to, from;
         for (int i = 0; i < e; i++) {
-            to = scanner.nextInt();
-            from = scanner.nextInt();
+            to = SCANNER.nextInt();
+            from = SCANNER.nextInt();
 
             adj.get(to).add(from);
             adj.get(from).add(to);
@@ -38,7 +38,7 @@ public static void main(String[] args) {
         dfs(adj, 0, -1, parent, depth);
 
         // Inputting the two vertices whose LCA is to be calculated
-        int v1 = scanner.nextInt(), v2 = scanner.nextInt();
+        int v1 = SCANNER.nextInt(), v2 = SCANNER.nextInt();
 
         // Outputting the LCA
         System.out.println(getLCA(v1, v2, depth, parent));
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
index c2e921c3aa36..81dd504ed791 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
@@ -9,7 +9,7 @@
  */
 public class Fibonacci {
 
-    private static final Map<Integer, Integer> map = new HashMap<>();
+    private static final Map<Integer, Integer> CACHE = new HashMap<>();
 
     public static void main(String[] args) {
         // Methods all returning [0, 1, 1, 2, 3, 5, ...] for n = [0, 1, 2, 3, 4, 5, ...]
@@ -30,8 +30,8 @@ public static void main(String[] args) {
      * Outputs the nth fibonacci number
      */
     public static int fibMemo(int n) {
-        if (map.containsKey(n)) {
-            return map.get(n);
+        if (CACHE.containsKey(n)) {
+            return CACHE.get(n);
         }
 
         int f;
@@ -40,7 +40,7 @@ public static int fibMemo(int n) {
             f = n;
         } else {
             f = fibMemo(n - 1) + fibMemo(n - 2);
-            map.put(n, f);
+            CACHE.put(n, f);
         }
         return f;
     }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
index af0447b95e67..3a4b687aea2c 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
@@ -6,8 +6,8 @@
 
 public class MatrixChainMultiplication {
 
-    private static final Scanner scan = new Scanner(System.in);
-    private static final ArrayList<Matrix> mArray = new ArrayList<>();
+    private static final Scanner SCANNER = new Scanner(System.in);
+    private static final ArrayList<Matrix> MATRICES = new ArrayList<>();
     private static int size;
     private static int[][] m;
     private static int[][] s;
@@ -24,14 +24,14 @@ public static void main(String[] args) {
             int row = Integer.parseInt(mSize[1]);
 
             Matrix matrix = new Matrix(count, col, row);
-            mArray.add(matrix);
+            MATRICES.add(matrix);
             count++;
         }
-        for (Matrix m : mArray) {
+        for (Matrix m : MATRICES) {
             System.out.format("A(%d)  =  %2d  x  %2d%n", m.count(), m.col(), m.row());
         }
 
-        size = mArray.size();
+        size = MATRICES.size();
         m = new int[size + 1][size + 1];
         s = new int[size + 1][size + 1];
         p = new int[size + 1];
@@ -42,7 +42,7 @@ public static void main(String[] args) {
         }
 
         for (int i = 0; i < p.length; i++) {
-            p[i] = i == 0 ? mArray.get(i).col() : mArray.get(i - 1).row();
+            p[i] = i == 0 ? MATRICES.get(i).col() : MATRICES.get(i - 1).row();
         }
 
         matrixChainOrder();
@@ -109,7 +109,7 @@ private static void matrixChainOrder() {
 
     private static String[] input(String string) {
         System.out.print(string);
-        return (scan.nextLine().split(" "));
+        return (SCANNER.nextLine().split(" "));
     }
 }
 
diff --git a/src/main/java/com/thealgorithms/maths/FindKthNumber.java b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
index bcb83b5ee2fc..0608cd0f1926 100644
--- a/src/main/java/com/thealgorithms/maths/FindKthNumber.java
+++ b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
@@ -8,7 +8,7 @@
  */
 public class FindKthNumber {
 
-    private static final Random random = new Random();
+    private static final Random RANDOM = new Random();
 
     public static void main(String[] args) {
         /* generate an array with random size and random elements */
@@ -29,11 +29,11 @@ public static void main(String[] args) {
     }
 
     private static int[] generateArray(int capacity) {
-        int size = random.nextInt(capacity) + 1;
+        int size = RANDOM.nextInt(capacity) + 1;
         int[] array = new int[size];
 
         for (int i = 0; i < size; i++) {
-            array[i] = random.nextInt() % 100;
+            array[i] = RANDOM.nextInt() % 100;
         }
         return array;
     }
diff --git a/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java b/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java
index aa255832f47f..b2e4576b6179 100644
--- a/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java
+++ b/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java
@@ -10,10 +10,10 @@
 public class Fibonacci {
 
     // Exponentiation matrix for Fibonacci sequence
-    private static final int[][] fibMatrix = {{1, 1}, {1, 0}};
-    private static final int[][] identityMatrix = {{1, 0}, {0, 1}};
+    private static final int[][] FIB_MATRIX = {{1, 1}, {1, 0}};
+    private static final int[][] IDENTITY_MATRIX = {{1, 0}, {0, 1}};
     // First 2 fibonacci numbers
-    private static final int[][] baseFibNumbers = {{1}, {0}};
+    private static final int[][] BASE_FIB_NUMBERS = {{1}, {0}};
 
     /**
      * Performs multiplication of 2 matrices
@@ -53,14 +53,14 @@ private static int[][] matrixMultiplication(int[][] matrix1, int[][] matrix2) {
      */
     public static int[][] fib(int n) {
         if (n == 0) {
-            return Fibonacci.identityMatrix;
+            return Fibonacci.IDENTITY_MATRIX;
         } else {
             int[][] cachedResult = fib(n / 2);
             int[][] matrixExpResult = matrixMultiplication(cachedResult, cachedResult);
             if (n % 2 == 0) {
                 return matrixExpResult;
             } else {
-                return matrixMultiplication(Fibonacci.fibMatrix, matrixExpResult);
+                return matrixMultiplication(Fibonacci.FIB_MATRIX, matrixExpResult);
             }
         }
     }
@@ -69,7 +69,7 @@ public static void main(String[] args) {
         // Returns [0, 1, 1, 2, 3, 5 ..] for n = [0, 1, 2, 3, 4, 5.. ]
         Scanner sc = new Scanner(System.in);
         int n = sc.nextInt();
-        int[][] result = matrixMultiplication(fib(n), baseFibNumbers);
+        int[][] result = matrixMultiplication(fib(n), BASE_FIB_NUMBERS);
         System.out.println("Fib(" + n + ") = " + result[1][0]);
         sc.close();
     }
diff --git a/src/main/java/com/thealgorithms/others/Conway.java b/src/main/java/com/thealgorithms/others/Conway.java
index b1d54e61094f..db1c102f8270 100644
--- a/src/main/java/com/thealgorithms/others/Conway.java
+++ b/src/main/java/com/thealgorithms/others/Conway.java
@@ -13,7 +13,7 @@ public class Conway {
      *1s, two 2s, one 1" or 312211. https://en.wikipedia.org/wiki/Look-and-say_sequence
      * */
 
-    private static final StringBuilder builder = new StringBuilder();
+    private static final StringBuilder BUILDER = new StringBuilder();
 
     protected static List<String> generateList(String originalString, int maxIteration) {
         List<String> numbers = new ArrayList<>();
@@ -25,9 +25,9 @@ protected static List<String> generateList(String originalString, int maxIterati
     }
 
     public static String generateNextElement(String originalString) {
-        builder.setLength(0);
+        BUILDER.setLength(0);
         String[] stp = originalString.split("(?<=(.))(?!\\1)");
-        Arrays.stream(stp).forEach(s -> builder.append(s.length()).append(s.charAt(0)));
-        return builder.toString();
+        Arrays.stream(stp).forEach(s -> BUILDER.append(s.length()).append(s.charAt(0)));
+        return BUILDER.toString();
     }
 }
diff --git a/src/main/java/com/thealgorithms/others/RabinKarp.java b/src/main/java/com/thealgorithms/others/RabinKarp.java
index 8757f03bab4b..6358ce4aaaba 100644
--- a/src/main/java/com/thealgorithms/others/RabinKarp.java
+++ b/src/main/java/com/thealgorithms/others/RabinKarp.java
@@ -9,15 +9,15 @@
 // Program will simply end if there is no match
 public class RabinKarp {
 
-    public static Scanner scanner = null;
-    public static final int d = 256;
+    public static Scanner SCANNER = null;
+    public static final int ALPHABET_SIZE = 256;
 
     public static void main(String[] args) {
-        scanner = new Scanner(System.in);
+        SCANNER = new Scanner(System.in);
         System.out.println("Enter String");
-        String text = scanner.nextLine();
+        String text = SCANNER.nextLine();
         System.out.println("Enter pattern");
-        String pattern = scanner.nextLine();
+        String pattern = SCANNER.nextLine();
 
         int q = 101;
         searchPat(text, pattern, q);
@@ -32,14 +32,14 @@ private static void searchPat(String text, String pattern, int q) {
         int j = 0;
         int i = 0;
 
-        h = (int) Math.pow(d, m - 1) % q;
+        h = (int) Math.pow(ALPHABET_SIZE, m - 1) % q;
 
         for (i = 0; i < m; i++) {
             // hash value is calculated for each character and then added with the hash value of the
             // next character for pattern as well as the text for length equal to the length of
             // pattern
-            p = (d * p + pattern.charAt(i)) % q;
-            t = (d * t + text.charAt(i)) % q;
+            p = (ALPHABET_SIZE * p + pattern.charAt(i)) % q;
+            t = (ALPHABET_SIZE * t + text.charAt(i)) % q;
         }
 
         for (i = 0; i <= n - m; i++) {
@@ -67,7 +67,7 @@ private static void searchPat(String text, String pattern, int q) {
             // value of the next character after the end of the evaluated characters is added to get
             // the hash value of the next window of characters in the text
             if (i < n - m) {
-                t = (d * (t - text.charAt(i) * h) + text.charAt(i + m)) % q;
+                t = (ALPHABET_SIZE * (t - text.charAt(i) * h) + text.charAt(i + m)) % q;
 
                 // if hash value becomes less than zero than q is added to make it positive
                 if (t < 0) {
diff --git a/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java b/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java
index e774546423f4..cc8387f6c4f3 100644
--- a/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java
+++ b/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java
@@ -6,8 +6,7 @@ public final class RabinKarpAlgorithm {
     private RabinKarpAlgorithm() {
     }
 
-    // d is the number of characters in the input alphabet
-    private static final int d = 256;
+    private static final int ALPHABET_SIZE = 256;
 
     public static int search(String pattern, String text, int primeNumber) {
 
@@ -19,13 +18,13 @@ public static int search(String pattern, String text, int primeNumber) {
         int h = 1;
 
         // The value of h would be "pow(d, patternLength-1)%primeNumber"
-        for (int i = 0; i < patternLength - 1; i++) h = (h * d) % primeNumber;
+        for (int i = 0; i < patternLength - 1; i++) h = (h * ALPHABET_SIZE) % primeNumber;
 
         // Calculate the hash value of pattern and first
         // window of text
         for (int i = 0; i < patternLength; i++) {
-            hashForPattern = (d * hashForPattern + pattern.charAt(i)) % primeNumber;
-            hashForText = (d * hashForText + text.charAt(i)) % primeNumber;
+            hashForPattern = (ALPHABET_SIZE * hashForPattern + pattern.charAt(i)) % primeNumber;
+            hashForText = (ALPHABET_SIZE * hashForText + text.charAt(i)) % primeNumber;
         }
 
         // Slide the pattern over text one by one
@@ -51,7 +50,7 @@ public static int search(String pattern, String text, int primeNumber) {
             // Calculate hash value for next window of text: Remove
             // leading digit, add trailing digit
             if (i < textLength - patternLength) {
-                hashForText = (d * (hashForText - text.charAt(i) * h) + text.charAt(i + patternLength)) % primeNumber;
+                hashForText = (ALPHABET_SIZE * (hashForText - text.charAt(i) * h) + text.charAt(i + patternLength)) % primeNumber;
 
                 // handling negative hashForText
                 if (hashForText < 0) hashForText = (hashForText + primeNumber);
diff --git a/src/main/java/com/thealgorithms/sorts/BogoSort.java b/src/main/java/com/thealgorithms/sorts/BogoSort.java
index 75f1e84367c3..7a1f7b216437 100644
--- a/src/main/java/com/thealgorithms/sorts/BogoSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BogoSort.java
@@ -8,7 +8,7 @@
  */
 public class BogoSort implements SortAlgorithm {
 
-    private static final Random random = new Random();
+    private static final Random RANDOM = new Random();
 
     private static <T extends Comparable<T>> boolean isSorted(T[] array) {
         for (int i = 0; i < array.length - 1; i++) {
@@ -24,7 +24,7 @@ private static <T> void nextPermutation(T[] array) {
         int length = array.length;
 
         for (int i = 0; i < array.length; i++) {
-            int randomIndex = i + random.nextInt(length - i);
+            int randomIndex = i + RANDOM.nextInt(length - i);
             SortUtils.swap(array, randomIndex, i);
         }
     }
diff --git a/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java b/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java
index e75b8e1e6f04..d39d40e79a7d 100644
--- a/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java
+++ b/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java
@@ -4,12 +4,12 @@
 
 public class SortUtilsRandomGenerator {
 
-    private static final Random random;
-    private static final long seed;
+    private static final Random RANDOM;
+    private static final long SEED;
 
     static {
-        seed = System.currentTimeMillis();
-        random = new Random(seed);
+        SEED = System.currentTimeMillis();
+        RANDOM = new Random(SEED);
     }
 
     /**
@@ -30,7 +30,7 @@ public static Double[] generateArray(int size) {
      * @return Double value [0, 1)
      */
     public static Double generateDouble() {
-        return random.nextDouble();
+        return RANDOM.nextDouble();
     }
 
     /**
@@ -39,6 +39,6 @@ public static Double generateDouble() {
      * @return int value [0, n)
      */
     public static int generateInt(int n) {
-        return random.nextInt(n);
+        return RANDOM.nextInt(n);
     }
 }

From b3903f57686e2212e984d2cc68aede2e7bcc0f64 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 3 May 2024 21:10:49 +0200
Subject: [PATCH 0138/1338] style: enable `RedundantModifier` in checkstyle
 (#5140)

---
 checkstyle.xml                                            | 2 +-
 .../java/com/thealgorithms/datastructures/bags/Bag.java   | 2 +-
 .../datastructures/bloomfilter/BloomFilter.java           | 2 +-
 .../datastructures/buffers/CircularBuffer.java            | 2 +-
 .../com/thealgorithms/datastructures/caches/LFUCache.java | 2 +-
 .../com/thealgorithms/datastructures/caches/LRUCache.java | 4 ++--
 .../com/thealgorithms/datastructures/caches/MRUCache.java | 4 ++--
 .../com/thealgorithms/datastructures/crdt/GCounter.java   | 2 +-
 .../thealgorithms/datastructures/crdt/LWWElementSet.java  | 4 ++--
 .../com/thealgorithms/datastructures/crdt/PNCounter.java  | 2 +-
 .../com/thealgorithms/datastructures/graphs/A_Star.java   | 6 +++---
 .../thealgorithms/datastructures/graphs/BellmanFord.java  | 2 +-
 .../datastructures/graphs/ConnectedComponent.java         | 6 +++---
 .../com/thealgorithms/datastructures/graphs/Cycles.java   | 2 +-
 .../com/thealgorithms/datastructures/graphs/Graphs.java   | 4 ++--
 .../com/thealgorithms/datastructures/graphs/Kruskal.java  | 2 +-
 .../thealgorithms/datastructures/graphs/MatrixGraphs.java | 2 +-
 .../hashmap/hashing/GenericHashMapUsingArrayList.java     | 2 +-
 .../datastructures/lists/DoublyLinkedList.java            | 2 +-
 .../com/thealgorithms/datastructures/lists/SkipList.java  | 2 +-
 .../thealgorithms/datastructures/queues/LinkedQueue.java  | 6 +++---
 .../datastructures/queues/PriorityQueues.java             | 4 ++--
 .../com/thealgorithms/datastructures/queues/Queues.java   | 4 ++--
 .../datastructures/stacks/StackOfLinkedList.java          | 4 ++--
 .../thealgorithms/datastructures/trees/BinaryTree.java    | 2 +-
 .../com/thealgorithms/datastructures/trees/KDTree.java    | 2 +-
 .../datastructures/trees/LazySegmentTree.java             | 2 +-
 .../datastructures/trees/PrintTopViewofTree.java          | 8 ++++----
 .../datastructures/trees/nearestRightKey.java             | 4 ++--
 .../com/thealgorithms/greedyalgorithms/JobSequencing.java | 2 +-
 src/main/java/com/thealgorithms/maths/FFT.java            | 4 ++--
 src/main/java/com/thealgorithms/misc/WordBoggle.java      | 2 +-
 src/main/java/com/thealgorithms/others/Dijkstra.java      | 6 +++---
 src/main/java/com/thealgorithms/others/KochSnowflake.java | 2 +-
 .../com/thealgorithms/others/QueueUsingTwoStacks.java     | 2 +-
 src/main/java/com/thealgorithms/others/TopKWords.java     | 2 +-
 .../scheduling/PreemptivePriorityScheduling.java          | 2 +-
 .../java/com/thealgorithms/sorts/TopologicalSort.java     | 4 ++--
 38 files changed, 59 insertions(+), 59 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 78ca487a414e..bff19ff79f17 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -148,7 +148,7 @@
     <!-- Modifier Checks                                    -->
     <!-- See https://checkstyle.org/checks/modifier/index.html -->
     <module name="ModifierOrder"/>
-    <!-- TODO <module name="RedundantModifier"/> -->
+    <module name="RedundantModifier"/>
 
     <!-- Checks for blocks. You know, those {}'s         -->
     <!-- See https://checkstyle.org/checks/blocks/index.html -->
diff --git a/src/main/java/com/thealgorithms/datastructures/bags/Bag.java b/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
index c82b9124bebc..66da3d34fcbf 100644
--- a/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
+++ b/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
@@ -80,7 +80,7 @@ private class ListIterator<Element> implements Iterator<Element> {
 
         private Node<Element> currentElement;
 
-        public ListIterator(Node<Element> firstElement) {
+        ListIterator(Node<Element> firstElement) {
             currentElement = firstElement;
         }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
index db85afa18c81..a327690d7896 100644
--- a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
+++ b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
@@ -42,7 +42,7 @@ private class Hash<T> {
 
         int index;
 
-        public Hash(int index) {
+        Hash(int index) {
             this.index = index;
         }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java b/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
index 5e1c815ff9b3..63295b83abe6 100644
--- a/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
+++ b/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
@@ -43,7 +43,7 @@ private static class CircularPointer {
         private int pointer;
         private final int max;
 
-        public CircularPointer(int pointer, int max) {
+        CircularPointer(int pointer, int max) {
             this.pointer = pointer;
             this.max = max;
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java b/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
index 03a1d59e1b20..6e37b4a7109d 100644
--- a/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
+++ b/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
@@ -17,7 +17,7 @@ private class Node {
         private Node previous;
         private Node next;
 
-        public Node(K key, V value, int frequency) {
+        Node(K key, V value, int frequency) {
             this.key = key;
             this.value = value;
             this.frequency = frequency;
diff --git a/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java b/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java
index fcb7d975bdb4..97818ff83351 100644
--- a/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java
+++ b/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java
@@ -126,10 +126,10 @@ static final class Entry<I, J> {
         private I key;
         private J value;
 
-        public Entry() {
+        Entry() {
         }
 
-        public Entry(Entry<I, J> preEntry, Entry<I, J> nextEntry, I key, J value) {
+        Entry(Entry<I, J> preEntry, Entry<I, J> nextEntry, I key, J value) {
             this.preEntry = preEntry;
             this.nextEntry = nextEntry;
             this.key = key;
diff --git a/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java b/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java
index 30f914968c3b..9c155be8b195 100644
--- a/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java
+++ b/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java
@@ -124,10 +124,10 @@ static final class Entry<I, J> {
         private I key;
         private J value;
 
-        public Entry() {
+        Entry() {
         }
 
-        public Entry(Entry<I, J> preEntry, Entry<I, J> nextEntry, I key, J value) {
+        Entry(Entry<I, J> preEntry, Entry<I, J> nextEntry, I key, J value) {
             this.preEntry = preEntry;
             this.nextEntry = nextEntry;
             this.key = key;
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java b/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java
index 63364f858ec5..ced55d87a3cf 100644
--- a/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java
@@ -26,7 +26,7 @@ class GCounter {
      *
      * @param n The number of nodes in the cluster.
      */
-    public GCounter(int myId, int n) {
+    GCounter(int myId, int n) {
         this.myId = myId;
         this.n = n;
         this.P = new HashMap<>();
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java b/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
index 722c916ab0ce..b8b296359844 100644
--- a/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
@@ -26,7 +26,7 @@ class Element {
      * @param timestamp The timestamp associated with the element.
      * @param bias      The bias of the element (ADDS or REMOVALS).
      */
-    public Element(String key, int timestamp, Bias bias) {
+    Element(String key, int timestamp, Bias bias) {
         this.key = key;
         this.timestamp = timestamp;
         this.bias = bias;
@@ -49,7 +49,7 @@ class LWWElementSet {
     /**
      * Constructs an empty LWWElementSet.
      */
-    public LWWElementSet() {
+    LWWElementSet() {
         this.addSet = new HashMap<>();
         this.removeSet = new HashMap<>();
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java b/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java
index 828e0b0804b3..04b846758f37 100644
--- a/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java
@@ -28,7 +28,7 @@ class PNCounter {
      * @param myId The identifier of the current node.
      * @param n    The number of nodes in the cluster.
      */
-    public PNCounter(int myId, int n) {
+    PNCounter(int myId, int n) {
         this.myId = myId;
         this.n = n;
         this.P = new HashMap<>();
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java b/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
index 8cd28378d9d3..6d02afbeb652 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
@@ -14,7 +14,7 @@ private static class Graph {
         private ArrayList<ArrayList<Edge>> graph;
 
         // Initialise ArrayLists in Constructor
-        public Graph(int size) {
+        Graph(int size) {
             this.graph = new ArrayList<>();
             for (int i = 0; i < size; i++) {
                 this.graph.add(new ArrayList<>());
@@ -38,7 +38,7 @@ private static class Edge {
         private int to;
         private int weight;
 
-        public Edge(int from, int to, int weight) {
+        Edge(int from, int to, int weight) {
             this.from = from;
             this.to = to;
             this.weight = weight;
@@ -64,7 +64,7 @@ private static class PathAndDistance {
         private ArrayList<Integer> path; // list of visited nodes in this path.
         private int estimated; // heuristic value associated to the last node od the path (current node).
 
-        public PathAndDistance(int distance, ArrayList<Integer> path, int estimated) {
+        PathAndDistance(int distance, ArrayList<Integer> path, int estimated) {
             this.distance = distance;
             this.path = path;
             this.estimated = estimated;
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
index 9f5022b44465..3251b7365b67 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
@@ -31,7 +31,7 @@ class Edge {
          * @param v End vertex
          * @param c Weight
          */
-        public Edge(int a, int b, int c) {
+        Edge(int a, int b, int c) {
             u = a;
             v = b;
             w = c;
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java b/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
index b0add255f59a..9b6ff9010445 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
@@ -15,7 +15,7 @@ class Node {
 
         E name;
 
-        public Node(E name) {
+        Node(E name) {
             this.name = name;
         }
     }
@@ -24,7 +24,7 @@ class Edge {
 
         Node startNode, endNode;
 
-        public Edge(Node startNode, Node endNode) {
+        Edge(Node startNode, Node endNode) {
             this.startNode = startNode;
             this.endNode = endNode;
         }
@@ -33,7 +33,7 @@ public Edge(Node startNode, Node endNode) {
     ArrayList<Edge> edgeList;
     ArrayList<Node> nodeList;
 
-    public Graph() {
+    Graph() {
         edgeList = new ArrayList<Edge>();
         nodeList = new ArrayList<Node>();
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java b/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
index 5d5bd3c7469c..7995e0146190 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
@@ -10,7 +10,7 @@ class Cycle {
     private boolean[] visited;
     ArrayList<ArrayList<Integer>> cycles = new ArrayList<ArrayList<Integer>>();
 
-    public Cycle() {
+    Cycle() {
         Scanner in = new Scanner(System.in);
         System.out.print("Enter the no. of nodes: ");
         nodes = in.nextInt();
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java b/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java
index 77cea399c173..01aa1085867b 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java
@@ -6,7 +6,7 @@ class AdjacencyListGraph<E extends Comparable<E>> {
 
     ArrayList<Vertex> vertices;
 
-    public AdjacencyListGraph() {
+    AdjacencyListGraph() {
         vertices = new ArrayList<>();
     }
 
@@ -15,7 +15,7 @@ private class Vertex {
         E data;
         ArrayList<Vertex> adjacentVertices;
 
-        public Vertex(E data) {
+        Vertex(E data) {
             adjacentVertices = new ArrayList<>();
             this.data = data;
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java b/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
index bf5afcd13fda..eb5b65d5c0d4 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
@@ -23,7 +23,7 @@ private static class Edge {
         private int to;
         private int weight;
 
-        public Edge(int from, int to, int weight) {
+        Edge(int from, int to, int weight) {
             this.from = from;
             this.to = to;
             this.weight = weight;
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java b/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
index 0348a60bc135..d595d53c1b61 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
@@ -68,7 +68,7 @@ class AdjacencyMatrixGraph {
     /**
      * Constructor
      */
-    public AdjacencyMatrixGraph(int givenNumberOfVertices) {
+    AdjacencyMatrixGraph(int givenNumberOfVertices) {
         this.setNumberOfVertices(givenNumberOfVertices);
         this.setNumberOfEdges(0);
         this.setAdjacency(new int[givenNumberOfVertices][givenNumberOfVertices]);
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java
index e45d827afec7..a1ef457f3432 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java
@@ -105,7 +105,7 @@ private class Node {
         K key;
         V val;
 
-        public Node(K key, V val) {
+        Node(K key, V val) {
             this.key = key;
             this.val = val;
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java
index 89117786c35e..7f10d7cd93a6 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java
@@ -110,7 +110,7 @@ class Link {
      *
      * @param value Value of node
      */
-    public Link(int value) {
+    Link(int value) {
         this.value = value;
     }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java b/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
index 33e3fd7cdb20..114a22d4b8c8 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
@@ -222,7 +222,7 @@ private static class Node<E> {
         private final List<Node<E>> backward;
 
         @SuppressWarnings("unchecked")
-        public Node(E value, int height) {
+        Node(E value, int height) {
             this.value = value;
             this.height = height;
 
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
index 8b33e08c3808..b552ac2918a3 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
@@ -11,15 +11,15 @@ static class Node<T> {
         T data;
         Node<T> next;
 
-        public Node() {
+        Node() {
             this(null);
         }
 
-        public Node(T data) {
+        Node(T data) {
             this(data, null);
         }
 
-        public Node(T data, Node<T> next) {
+        Node(T data, Node<T> next) {
             this.data = data;
             this.next = next;
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java b/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java
index dec25d2ff694..16a0c1673886 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java
@@ -30,7 +30,7 @@ class PriorityQueue {
      * Default Constructor
      */
 
-    public PriorityQueue() {
+    PriorityQueue() {
         /* If capacity is not defined, default size of 11 would be used
          *  capacity=max+1 because we cant access 0th element of PQ, and to
          *  accomodate (max)th elements we need capacity to be max+1.
@@ -50,7 +50,7 @@ public PriorityQueue() {
      * @param size Size of the queue
      */
 
-    public PriorityQueue(int size) {
+    PriorityQueue(int size) {
         maxSize = size + 1;
         queueArray = new int[maxSize];
         nItems = 0;
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/Queues.java b/src/main/java/com/thealgorithms/datastructures/queues/Queues.java
index bcc292b3e9a9..a8fabf7b8859 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/Queues.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/Queues.java
@@ -38,7 +38,7 @@ class Queue {
     /**
      * init with DEFAULT_CAPACITY
      */
-    public Queue() {
+    Queue() {
         this(DEFAULT_CAPACITY);
     }
 
@@ -47,7 +47,7 @@ public Queue() {
      *
      * @param size Size of the new queue
      */
-    public Queue(int size) {
+    Queue(int size) {
         maxSize = size;
         queueArray = new int[size];
         front = 0;
diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java b/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java
index 0463018fde82..afe002fa3651 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java
@@ -33,7 +33,7 @@ class Node {
     public int data;
     public Node next;
 
-    public Node(int data) {
+    Node(int data) {
         this.data = data;
         this.next = null;
     }
@@ -60,7 +60,7 @@ class LinkedListStack {
     /**
      * Init properties
      */
-    public LinkedListStack() {
+    LinkedListStack() {
         head = null;
         size = 0;
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java b/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java
index d699b436d6b9..d4d677a4cda0 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java
@@ -47,7 +47,7 @@ static class Node {
          *
          * @param value Value to put in the node
          */
-        public Node(int value) {
+        Node(int value) {
             data = value;
             left = null;
             right = null;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java b/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
index 577c0055d9b6..c3be07eef0ab 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
@@ -68,7 +68,7 @@ public int getDimension() {
             return coordinates.length;
         }
 
-        public Point(int[] coordinates) {
+        Point(int[] coordinates) {
             this.coordinates = coordinates;
         }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java b/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java
index b5a9db9f5e11..6eff3c38b94c 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java
@@ -15,7 +15,7 @@ static class Node {
         private int lazy; // lazied value that should be added to children nodes
         Node left, right; // left and right children
 
-        public Node(int start, int end, int value) {
+        Node(int start, int end, int value) {
             this.start = start;
             this.end = end;
             this.value = value;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java b/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
index a2dbeca5ebac..7560e90cd008 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
@@ -13,7 +13,7 @@ class TreeNode {
     TreeNode left, right;
 
     // Constructor
-    public TreeNode(int key) {
+    TreeNode(int key) {
         this.key = key;
         left = right = null;
     }
@@ -27,7 +27,7 @@ class QItem {
     TreeNode node;
     int hd;
 
-    public QItem(TreeNode n, int h) {
+    QItem(TreeNode n, int h) {
         node = n;
         hd = h;
     }
@@ -39,11 +39,11 @@ class Tree {
     TreeNode root;
 
     // Constructors
-    public Tree() {
+    Tree() {
         root = null;
     }
 
-    public Tree(TreeNode n) {
+    Tree(TreeNode n) {
         root = n;
     }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java b/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java
index 913ccda3828c..dd6df1481c99 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java
@@ -53,13 +53,13 @@ class NRKTree {
     public NRKTree right;
     public int data;
 
-    public NRKTree(int x) {
+    NRKTree(int x) {
         this.left = null;
         this.right = null;
         this.data = x;
     }
 
-    public NRKTree(NRKTree right, NRKTree left, int x) {
+    NRKTree(NRKTree right, NRKTree left, int x) {
         this.left = left;
         this.right = right;
         this.data = x;
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
index 83ed40d2a1be..113918263cd3 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
@@ -19,7 +19,7 @@ public int compareTo(Job otherJob) {
             return otherJob.profit - this.profit;
         }
 
-        public Job(char id, int deadline, int profit) {
+        Job(char id, int deadline, int profit) {
             this.id = id;
             this.deadline = deadline;
             this.profit = profit;
diff --git a/src/main/java/com/thealgorithms/maths/FFT.java b/src/main/java/com/thealgorithms/maths/FFT.java
index f50bec52997b..f745917749e5 100644
--- a/src/main/java/com/thealgorithms/maths/FFT.java
+++ b/src/main/java/com/thealgorithms/maths/FFT.java
@@ -27,7 +27,7 @@ static class Complex {
         /**
          * Default Constructor. Creates the complex number 0.
          */
-        public Complex() {
+        Complex() {
             real = 0;
             img = 0;
         }
@@ -38,7 +38,7 @@ public Complex() {
          * @param r The real part of the number.
          * @param i The imaginary part of the number.
          */
-        public Complex(double r, double i) {
+        Complex(double r, double i) {
             real = r;
             img = i;
         }
diff --git a/src/main/java/com/thealgorithms/misc/WordBoggle.java b/src/main/java/com/thealgorithms/misc/WordBoggle.java
index 0dfbd89def99..5b3b8f86af10 100644
--- a/src/main/java/com/thealgorithms/misc/WordBoggle.java
+++ b/src/main/java/com/thealgorithms/misc/WordBoggle.java
@@ -127,7 +127,7 @@ class Trie {
     TrieNode root;
     char endSymbol;
 
-    public Trie() {
+    Trie() {
         this.root = new TrieNode();
         this.endSymbol = '*';
     }
diff --git a/src/main/java/com/thealgorithms/others/Dijkstra.java b/src/main/java/com/thealgorithms/others/Dijkstra.java
index 4886dc4ce7a4..3218c7bf43de 100644
--- a/src/main/java/com/thealgorithms/others/Dijkstra.java
+++ b/src/main/java/com/thealgorithms/others/Dijkstra.java
@@ -61,7 +61,7 @@ public static class Edge {
         public final String v1, v2;
         public final int dist;
 
-        public Edge(String v1, String v2, int dist) {
+        Edge(String v1, String v2, int dist) {
             this.v1 = v1;
             this.v2 = v2;
             this.dist = dist;
@@ -79,7 +79,7 @@ public static class Vertex implements Comparable<Vertex> {
         public Vertex previous = null;
         public final Map<Vertex, Integer> neighbours = new HashMap<>();
 
-        public Vertex(String name) {
+        Vertex(String name) {
             this.name = name;
         }
 
@@ -147,7 +147,7 @@ public String toString() {
     /**
      * Builds a graph from a set of edges
      */
-    public Graph(Edge[] edges) {
+    Graph(Edge[] edges) {
         graph = new HashMap<>(edges.length);
 
         // one pass to find all vertices
diff --git a/src/main/java/com/thealgorithms/others/KochSnowflake.java b/src/main/java/com/thealgorithms/others/KochSnowflake.java
index 8395b1f486a7..04abc2dd8993 100644
--- a/src/main/java/com/thealgorithms/others/KochSnowflake.java
+++ b/src/main/java/com/thealgorithms/others/KochSnowflake.java
@@ -176,7 +176,7 @@ private static class Vector2 {
 
         double x, y;
 
-        public Vector2(double x, double y) {
+        Vector2(double x, double y) {
             this.x = x;
             this.y = y;
         }
diff --git a/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java b/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java
index 6b766dc3f5a0..2499d9373354 100644
--- a/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java
+++ b/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java
@@ -25,7 +25,7 @@ class QueueWithStack {
     /**
      * Constructor
      */
-    public QueueWithStack() {
+    QueueWithStack() {
         this.inStack = new Stack<>();
         this.outStack = new Stack<>();
     }
diff --git a/src/main/java/com/thealgorithms/others/TopKWords.java b/src/main/java/com/thealgorithms/others/TopKWords.java
index 664a3ec92eac..43e71173d096 100644
--- a/src/main/java/com/thealgorithms/others/TopKWords.java
+++ b/src/main/java/com/thealgorithms/others/TopKWords.java
@@ -11,7 +11,7 @@ static class CountWords {
 
         private String fileName;
 
-        public CountWords(String fileName) {
+        CountWords(String fileName) {
             this.fileName = fileName;
         }
 
diff --git a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
index 7b058bcee625..4523f6824410 100644
--- a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
@@ -13,7 +13,7 @@ class Process {
     int burstTime;
     int priority;
 
-    public Process(String name, int arrivalTime, int burstTime, int priority) {
+    Process(String name, int arrivalTime, int burstTime, int priority) {
         this.name = name;
         this.arrivalTime = arrivalTime;
         this.burstTime = burstTime;
diff --git a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
index 76d527ce756d..1ba918275b7d 100644
--- a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
@@ -43,7 +43,7 @@ private static class Vertex {
          * */
         public final ArrayList<String> next = new ArrayList<>();
 
-        public Vertex(String label) {
+        Vertex(String label) {
             this.label = label;
         }
     }
@@ -69,7 +69,7 @@ public void addEdge(String label, String... next) {
 
     static class BackEdgeException extends RuntimeException {
 
-        public BackEdgeException(String backEdge) {
+        BackEdgeException(String backEdge) {
             super("This graph contains a cycle. No linear ordering is possible. " + backEdge);
         }
     }

From dda3c9cb5923719961c6b826dc9daf74d8b00f89 Mon Sep 17 00:00:00 2001
From: SOZEL <80200848+TruongNhanNguyen@users.noreply.github.com>
Date: Sat, 4 May 2024 16:13:30 +0700
Subject: [PATCH 0139/1338] Refactor Levenshtein distance implementation
 (#5138)

* ref: refactor Levenshtein distance implementation
- Rewrite the original levenshtein distance implementation in functional style
- Add optimized version of levenshtein distance

* ref: make `LevenshteinDistance` class a proper utility

* ref: remove duplicated test data

* ref: update tests

---

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../LevenshteinDistance.java                  | 109 ++++++++++++------
 .../LevenshteinDistanceTests.java             |  39 ++++++-
 2 files changed, 106 insertions(+), 42 deletions(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java b/src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java
index c4c9bbee9a78..119d65dfe365 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java
@@ -1,49 +1,84 @@
 package com.thealgorithms.dynamicprogramming;
 
+import java.util.stream.IntStream;
+
 /**
- * @author Kshitij VERMA (github.com/kv19971) LEVENSHTEIN DISTANCE dyamic
- * programming implementation to show the difference between two strings
- * (https://en.wikipedia.org/wiki/Levenshtein_distance)
+ * Provides functions to calculate the Levenshtein distance between two strings.
+ *
+ * The Levenshtein distance is a measure of the similarity between two strings by calculating the minimum number of single-character
+ * edits (insertions, deletions, or substitutions) required to change one string into the other.
  */
-public class LevenshteinDistance {
-
-    private static int minimum(int a, int b, int c) {
-        if (a < b && a < c) {
-            return a;
-        } else if (b < a && b < c) {
-            return b;
-        } else {
-            return c;
-        }
+public final class LevenshteinDistance {
+    private LevenshteinDistance() {
     }
 
-    public static int calculateLevenshteinDistance(String str1, String str2) {
-        int len1 = str1.length() + 1;
-        int len2 = str2.length() + 1;
-        int[][] distanceMat = new int[len1][len2];
-        for (int i = 0; i < len1; i++) {
-            distanceMat[i][0] = i;
-        }
-        for (int j = 0; j < len2; j++) {
-            distanceMat[0][j] = j;
+    /**
+     * Calculates the Levenshtein distance between two strings using a naive dynamic programming approach.
+     *
+     * This function computes the Levenshtein distance by constructing a dynamic programming matrix and iteratively filling it in.
+     * It follows the standard top-to-bottom, left-to-right approach for filling in the matrix.
+     *
+     * @param string1 The first string.
+     * @param string2 The second string.
+     * @return The Levenshtein distance between the two input strings.
+     *
+     * Time complexity: O(nm),
+     * Space complexity: O(nm),
+     *
+     * where n and m are lengths of `string1` and `string2`.
+     *
+     * Note that this implementation uses a straightforward dynamic programming approach without any space optimization.
+     * It may consume more memory for larger input strings compared to the optimized version.
+     */
+    public static int naiveLevenshteinDistance(final String string1, final String string2) {
+        int[][] distanceMatrix = IntStream.rangeClosed(0, string1.length()).mapToObj(i -> IntStream.rangeClosed(0, string2.length()).map(j -> (i == 0) ? j : (j == 0) ? i : 0).toArray()).toArray(int[][] ::new);
+
+        IntStream.range(1, string1.length() + 1).forEach(i -> IntStream.range(1, string2.length() + 1).forEach(j -> {
+            final int cost = (string1.charAt(i - 1) == string2.charAt(j - 1)) ? 0 : 1;
+            distanceMatrix[i][j] = Math.min(distanceMatrix[i - 1][j - 1] + cost, Math.min(distanceMatrix[i][j - 1] + 1, distanceMatrix[i - 1][j] + 1));
+        }));
+
+        return distanceMatrix[string1.length()][string2.length()];
+    }
+
+    /**
+     * Calculates the Levenshtein distance between two strings using an optimized dynamic programming approach.
+     *
+     * This edit distance is defined as 1 point per insertion, substitution, or deletion required to make the strings equal.
+     *
+     * @param string1 The first string.
+     * @param string2 The second string.
+     * @return The Levenshtein distance between the two input strings.
+     *
+     * Time complexity: O(nm),
+     * Space complexity: O(n),
+     *
+     * where n and m are lengths of `string1` and `string2`.
+     *
+     * Note that this implementation utilizes an optimized dynamic programming approach, significantly reducing the space complexity from O(nm) to O(n), where n and m are the lengths of `string1` and `string2`.
+     *
+     * Additionally, it minimizes space usage by leveraging the shortest string horizontally and the longest string vertically in the computation matrix.
+     */
+    public static int optimizedLevenshteinDistance(final String string1, final String string2) {
+        if (string1.isEmpty()) {
+            return string2.length();
         }
-        for (int i = 1; i < len1; i++) {
-            for (int j = 1; j < len2; j++) {
-                if (str1.charAt(i - 1) == str2.charAt(j - 1)) {
-                    distanceMat[i][j] = distanceMat[i - 1][j - 1];
-                } else {
-                    distanceMat[i][j] = 1 + minimum(distanceMat[i - 1][j], distanceMat[i - 1][j - 1], distanceMat[i][j - 1]);
-                }
+
+        int[] previousDistance = IntStream.rangeClosed(0, string1.length()).toArray();
+
+        for (int j = 1; j <= string2.length(); j++) {
+            int prevSubstitutionCost = previousDistance[0];
+            previousDistance[0] = j;
+
+            for (int i = 1; i <= string1.length(); i++) {
+                final int deletionCost = previousDistance[i] + 1;
+                final int insertionCost = previousDistance[i - 1] + 1;
+                final int substitutionCost = (string1.charAt(i - 1) == string2.charAt(j - 1)) ? prevSubstitutionCost : prevSubstitutionCost + 1;
+                prevSubstitutionCost = previousDistance[i];
+                previousDistance[i] = Math.min(deletionCost, Math.min(insertionCost, substitutionCost));
             }
         }
-        return distanceMat[len1 - 1][len2 - 1];
-    }
-
-    public static void main(String[] args) {
-        String str1 = ""; // enter your string here
-        String str2 = ""; // enter your string here
 
-        System.out.print("Levenshtein distance between " + str1 + " and " + str2 + " is: ");
-        System.out.println(calculateLevenshteinDistance(str1, str2));
+        return previousDistance[string1.length()];
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java b/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java
index a22bf3fea30c..ad4c4c7c53e0 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java
@@ -2,15 +2,44 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.ToIntBiFunction;
+import java.util.stream.Stream;
 import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class LevenshteinDistanceTests {
 
     @ParameterizedTest
-    @CsvSource({"dog,cat,3", "sunday,saturday,3", "cat,cats,1", "rain,train,1"})
-    void levenshteinDistanceTest(String str1, String str2, int distance) {
-        int result = LevenshteinDistance.calculateLevenshteinDistance(str1, str2);
-        assertEquals(distance, result);
+    @MethodSource("testCases")
+    public void testLevenshteinDistance(final int expected, final String str1, final String str2, final ToIntBiFunction<String, String> dist) {
+        assertEquals(expected, dist.applyAsInt(str1, str2));
+        assertEquals(expected, dist.applyAsInt(str2, str1));
+        assertEquals(0, dist.applyAsInt(str1, str1));
+        assertEquals(0, dist.applyAsInt(str2, str2));
+    }
+
+    private static Stream<Arguments> testCases() {
+        final Object[][] testData = {
+            {0, "", ""},
+            {0, "Hello, World!", "Hello, World!"},
+            {4, "", "Rust"},
+            {3, "horse", "ros"},
+            {6, "tan", "elephant"},
+            {8, "execute", "intention"},
+            {1, "a", "b"},
+            {1, "a", "aa"},
+            {1, "a", ""},
+            {1, "a", "ab"},
+            {1, "a", "ba"},
+            {2, "a", "bc"},
+            {2, "a", "cb"},
+        };
+
+        final List<ToIntBiFunction<String, String>> methods = Arrays.asList(LevenshteinDistance::naiveLevenshteinDistance, LevenshteinDistance::optimizedLevenshteinDistance);
+
+        return Stream.of(testData).flatMap(input -> methods.stream().map(method -> Arguments.of(input[0], input[1], input[2], method)));
     }
 }

From 6bde5d7ed5e21f0ec5c8da917f8d444567cbb1d5 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 4 May 2024 17:57:59 +0200
Subject: [PATCH 0140/1338] chore: configure SpotBugs plugin `fb-contrib`
 (#5126)

---
 pom.xml              |   7 ++
 spotbugs-exclude.xml | 160 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 167 insertions(+)

diff --git a/pom.xml b/pom.xml
index b823f9e3563b..b8a7e22a45cf 100644
--- a/pom.xml
+++ b/pom.xml
@@ -121,6 +121,13 @@
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>
+                    <plugins>
+                        <plugin>
+                            <groupId>com.mebigfatguy.fb-contrib</groupId>
+                            <artifactId>fb-contrib</artifactId>
+                            <version>7.6.4</version>
+                        </plugin>
+                    </plugins>
                 </configuration>
             </plugin>
         </plugins>
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 799a72fa91cf..45eceb0d3de9 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -125,4 +125,164 @@
     <Match>
         <Bug pattern="RV_ABSOLUTE_VALUE_OF_HASHCODE" />
     </Match>
+    <!-- fb-contrib -->
+    <Match>
+        <Bug pattern="OCP_OVERLY_CONCRETE_PARAMETER" />
+    </Match>
+    <Match>
+        <Bug pattern="NAB_NEEDLESS_BOOLEAN_CONSTANT_CONVERSION" />
+    </Match>
+    <Match>
+        <Bug pattern="LSC_LITERAL_STRING_COMPARISON" />
+    </Match>
+    <Match>
+        <Bug pattern="CE_CLASS_ENVY" />
+    </Match>
+    <Match>
+        <Bug pattern="PSC_PRESIZE_COLLECTIONS" />
+    </Match>
+    <Match>
+        <Bug pattern="SACM_STATIC_ARRAY_CREATED_IN_METHOD" />
+    </Match>
+    <Match>
+        <Bug pattern="LUI_USE_SINGLETON_LIST" />
+    </Match>
+    <Match>
+        <Bug pattern="CLI_CONSTANT_LIST_INDEX" />
+    </Match>
+    <Match>
+        <Bug pattern="BED_BOGUS_EXCEPTION_DECLARATION" />
+    </Match>
+    <Match>
+        <Bug pattern="CNC_COLLECTION_NAMING_CONFUSION" />
+    </Match>
+    <Match>
+        <Bug pattern="TR_TAIL_RECURSION" />
+    </Match>
+    <Match>
+        <Bug pattern="LII_LIST_INDEXED_ITERATING" />
+    </Match>
+    <Match>
+        <Bug pattern="USBR_UNNECESSARY_STORE_BEFORE_RETURN" />
+    </Match>
+    <Match>
+        <Bug pattern="MAC_MANUAL_ARRAY_COPY" />
+    </Match>
+    <Match>
+        <Bug pattern="SPP_USE_ISEMPTY" />
+    </Match>
+    <Match>
+        <Bug pattern="BL_BURYING_LOGIC" />
+    </Match>
+    <Match>
+        <Bug pattern="OI_OPTIONAL_ISSUES_USES_IMMEDIATE_EXECUTION" />
+    </Match>
+    <Match>
+        <Bug pattern="PCOA_PARTIALLY_CONSTRUCTED_OBJECT_ACCESS" />
+    </Match>
+    <Match>
+        <Bug pattern="UTWR_USE_TRY_WITH_RESOURCES" />
+    </Match>
+    <Match>
+        <Bug pattern="MUI_CONTAINSKEY_BEFORE_GET" />
+    </Match>
+    <Match>
+        <Bug pattern="IMC_IMMATURE_CLASS_PRINTSTACKTRACE" />
+    </Match>
+    <Match>
+        <Bug pattern="UCPM_USE_CHARACTER_PARAMETERIZED_METHOD" />
+    </Match>
+    <Match>
+        <Bug pattern="SUA_SUSPICIOUS_UNINITIALIZED_ARRAY" />
+    </Match>
+    <Match>
+        <Bug pattern="SPP_USE_MATH_CONSTANT" />
+    </Match>
+    <Match>
+        <Bug pattern="UJM_UNJITABLE_METHOD" />
+    </Match>
+    <Match>
+        <Bug pattern="SEC_SIDE_EFFECT_CONSTRUCTOR" />
+    </Match>
+    <Match>
+        <Bug pattern="MDM_STRING_BYTES_ENCODING" />
+    </Match>
+    <Match>
+        <Bug pattern="PMB_POSSIBLE_MEMORY_BLOAT" />
+    </Match>
+    <Match>
+        <Bug pattern="LSYC_LOCAL_SYNCHRONIZED_COLLECTION" />
+    </Match>
+    <Match>
+        <Bug pattern="IOI_USE_OF_FILE_STREAM_CONSTRUCTORS" />
+    </Match>
+    <Match>
+        <Bug pattern="UP_UNUSED_PARAMETER" />
+    </Match>
+    <Match>
+        <Bug pattern="DSOC_DUBIOUS_SET_OF_COLLECTIONS" />
+    </Match>
+    <Match>
+        <Bug pattern="NAB_NEEDLESS_BOX_TO_UNBOX" />
+    </Match>
+    <Match>
+        <Bug pattern="FPL_FLOATING_POINT_LOOPS" />
+    </Match>
+    <Match>
+        <Bug pattern="ITU_INAPPROPRIATE_TOSTRING_USE" />
+    </Match>
+    <Match>
+        <Bug pattern="DMC_DUBIOUS_MAP_COLLECTION" />
+    </Match>
+    <Match>
+        <Bug pattern="SPP_PASSING_THIS_AS_PARM" />
+    </Match>
+    <Match>
+        <Bug pattern="FCBL_FIELD_COULD_BE_LOCAL" />
+    </Match>
+    <Match>
+        <Bug pattern="ENMI_EQUALS_ON_ENUM" />
+    </Match>
+    <Match>
+        <Bug pattern="NAB_NEEDLESS_BOXING_PARSE" />
+    </Match>
+    <Match>
+        <Bug pattern="IMC_IMMATURE_CLASS_VAR_NAME" />
+    </Match>
+    <Match>
+        <Bug pattern="CFS_CONFUSING_FUNCTION_SEMANTICS" />
+    </Match>
+    <Match>
+        <Bug pattern="PRMC_POSSIBLY_REDUNDANT_METHOD_CALLS" />
+    </Match>
+    <Match>
+        <Bug pattern="FCCD_FIND_CLASS_CIRCULAR_DEPENDENCY" />
+    </Match>
+    <Match>
+        <Bug pattern="LEST_LOST_EXCEPTION_STACK_TRACE" />
+    </Match>
+    <Match>
+        <Bug pattern="PL_PARALLEL_LISTS" />
+    </Match>
+    <Match>
+        <Bug pattern="PCAIL_POSSIBLE_CONSTANT_ALLOCATION_IN_LOOP" />
+    </Match>
+    <Match>
+        <Bug pattern="STT_STRING_PARSING_A_FIELD" />
+    </Match>
+    <Match>
+        <Bug pattern="IMC_IMMATURE_CLASS_BAD_SERIALVERSIONUID" />
+    </Match>
+    <Match>
+        <Bug pattern="SUI_CONTAINS_BEFORE_ADD" />
+    </Match>
+    <Match>
+        <Bug pattern="DRE_DECLARED_RUNTIME_EXCEPTION" />
+    </Match>
+    <Match>
+        <Bug pattern="SLS_SUSPICIOUS_LOOP_SEARCH" />
+    </Match>
+    <Match>
+        <Bug pattern="SPP_TOSTRING_ON_STRING" />
+    </Match>
 </FindBugsFilter>

From 5d00889291f21930af03a414691bfc069565c3f9 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 5 May 2024 20:26:54 +0200
Subject: [PATCH 0141/1338] fix: handle empty inputs in `CircleSort` (#5121)

* fix: handle empty inputs in `CircleSort`

* style: remove `main` method
---
 .../com/thealgorithms/sorts/CircleSort.java   | 20 +++----------------
 .../thealgorithms/sorts/CircleSortTest.java   |  8 ++++++++
 2 files changed, 11 insertions(+), 17 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/sorts/CircleSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/CircleSort.java b/src/main/java/com/thealgorithms/sorts/CircleSort.java
index 7f2dc5fdfef5..c6a6d9ea3658 100644
--- a/src/main/java/com/thealgorithms/sorts/CircleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CircleSort.java
@@ -10,6 +10,9 @@ public class CircleSort implements SortAlgorithm {
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
         int n = array.length;
+        if (n == 0) {
+            return array;
+        }
         while (doSort(array, 0, n - 1)) {
         }
         return array;
@@ -50,21 +53,4 @@ private <T extends Comparable<T>> Boolean doSort(T[] array, int left, int right)
 
         return swapped || leftHalf || rightHalf;
     }
-
-    /* Driver code*/
-    public static void main(String[] args) {
-        CircleSort CSort = new CircleSort();
-
-        Integer[] arr = {4, 23, 6, 78, 1, 54, 231, 9, 12};
-        CSort.sort(arr);
-        for (int i = 0; i < arr.length - 1; ++i) {
-            assert arr[i] <= arr[i + 1];
-        }
-
-        String[] stringArray = {"c", "a", "e", "b", "d"};
-        CSort.sort(stringArray);
-        for (int i = 0; i < stringArray.length - 1; ++i) {
-            assert arr[i].compareTo(arr[i + 1]) <= 0;
-        }
-    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/CircleSortTest.java b/src/test/java/com/thealgorithms/sorts/CircleSortTest.java
new file mode 100644
index 000000000000..d113473272b7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/CircleSortTest.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.sorts;
+
+class CircleSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new CircleSort();
+    }
+}

From dc47e0aa42132bd67b12e88993497df35a3cc25d Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 5 May 2024 20:39:26 +0200
Subject: [PATCH 0142/1338] style: include
 `ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD` (#5129)

---
 spotbugs-exclude.xml                                    | 3 ---
 src/main/java/com/thealgorithms/sorts/LinkListSort.java | 4 ++--
 src/main/java/com/thealgorithms/sorts/MergeSort.java    | 6 +++---
 src/main/java/com/thealgorithms/sorts/TimSort.java      | 5 ++---
 4 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 45eceb0d3de9..4ef8fe8de448 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -5,9 +5,6 @@
     <Match>
         <Bug pattern="EI_EXPOSE_REP2" />
     </Match>
-    <Match>
-        <Bug pattern="ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD" />
-    </Match>
     <Match>
         <Bug pattern="DMI_RANDOM_USED_ONLY_ONCE" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/sorts/LinkListSort.java b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
index e679fa9f03e7..fb99439b949d 100644
--- a/src/main/java/com/thealgorithms/sorts/LinkListSort.java
+++ b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
@@ -137,7 +137,7 @@ class Node {
 
 class Task {
 
-    static int[] a;
+    private int[] a;
 
     public Node sortByMergeSort(Node head) {
         if (head == null || head.next == null) return head;
@@ -245,7 +245,7 @@ static int count(Node head) {
 
 class Task2 {
 
-    static int[] a;
+    private int[] a;
 
     public Node sortByHeapSort(Node head) {
         if (head == null || head.next == null) return head;
diff --git a/src/main/java/com/thealgorithms/sorts/MergeSort.java b/src/main/java/com/thealgorithms/sorts/MergeSort.java
index 0950b46891ce..f4953e71d009 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSort.java
@@ -9,7 +9,7 @@
  */
 class MergeSort implements SortAlgorithm {
 
-    @SuppressWarnings("rawtypes") private static Comparable[] aux;
+    private Comparable[] aux;
 
     /**
      * Generic merge sort algorithm implements.
@@ -30,7 +30,7 @@ public <T extends Comparable<T>> T[] sort(T[] unsorted) {
      * @param left the first index of the array.
      * @param right the last index of the array.
      */
-    private static <T extends Comparable<T>> void doSort(T[] arr, int left, int right) {
+    private <T extends Comparable<T>> void doSort(T[] arr, int left, int right) {
         if (left < right) {
             int mid = (left + right) >>> 1;
             doSort(arr, left, mid);
@@ -49,7 +49,7 @@ private static <T extends Comparable<T>> void doSort(T[] arr, int left, int righ
      * increasing order.
      */
     @SuppressWarnings("unchecked")
-    private static <T extends Comparable<T>> void merge(T[] arr, int left, int mid, int right) {
+    private <T extends Comparable<T>> void merge(T[] arr, int left, int mid, int right) {
         int i = left, j = mid + 1;
         System.arraycopy(arr, left, aux, left, right + 1 - left);
 
diff --git a/src/main/java/com/thealgorithms/sorts/TimSort.java b/src/main/java/com/thealgorithms/sorts/TimSort.java
index be7eaa275c91..bb7ed8d549f4 100644
--- a/src/main/java/com/thealgorithms/sorts/TimSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TimSort.java
@@ -9,7 +9,7 @@
  */
 class TimSort implements SortAlgorithm {
     private static final int SUB_ARRAY_SIZE = 32;
-    @SuppressWarnings("rawtypes") private static Comparable[] aux;
+    private Comparable[] aux;
 
     @Override
     public <T extends Comparable<T>> T[] sort(T[] a) {
@@ -30,8 +30,7 @@ public <T extends Comparable<T>> T[] sort(T[] a) {
         return a;
     }
 
-    @SuppressWarnings("unchecked")
-    private static <T extends Comparable<T>> void merge(T[] a, int lo, int mid, int hi) {
+    private <T extends Comparable<T>> void merge(T[] a, int lo, int mid, int hi) {
         int i = lo, j = mid + 1;
         System.arraycopy(a, lo, aux, lo, hi + 1 - lo);
 

From 414835db1170cb5a0df478388f7052018f4364ae Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 5 May 2024 20:48:56 +0200
Subject: [PATCH 0143/1338] style: enable `AvoidStarImport` in checkstyle
 (#5141)

---
 checkstyle.xml                                |  2 +-
 .../AllPathsFromSourceToTarget.java           |  3 +-
 .../backtracking/ArrayCombination.java        |  3 +-
 .../backtracking/Combination.java             |  5 +-
 .../backtracking/KnightsTour.java             |  4 +-
 .../thealgorithms/backtracking/MColoring.java |  6 ++-
 .../thealgorithms/ciphers/AESEncryption.java  |  7 ++-
 .../conversions/BinaryToHexadecimal.java      |  3 +-
 .../conversions/RomanToInteger.java           |  3 +-
 .../dynamicarray/DynamicArray.java            |  6 ++-
 .../datastructures/graphs/A_Star.java         |  6 ++-
 .../datastructures/graphs/BellmanFord.java    |  2 +-
 .../datastructures/heaps/GenericHeap.java     |  3 +-
 .../datastructures/lists/SkipList.java        |  7 ++-
 .../trees/PostOrderTraversal.java             |  6 ++-
 .../datastructures/trees/ZigzagTraversal.java |  6 ++-
 .../maths/DeterminantOfMatrix.java            |  2 +-
 .../thealgorithms/maths/KaprekarNumbers.java  |  3 +-
 .../com/thealgorithms/maths/KeithNumber.java  |  4 +-
 .../maths/KrishnamurthyNumber.java            |  4 +-
 .../maths/LeastCommonMultiple.java            |  2 +-
 .../com/thealgorithms/maths/MagicSquare.java  |  2 +-
 .../misc/RangeInSortedArray.java              |  2 +-
 .../java/com/thealgorithms/misc/Sort012D.java |  2 +-
 .../java/com/thealgorithms/misc/Sparcity.java |  2 +-
 .../thealgorithms/misc/ThreeSumProblem.java   | 10 +++-
 .../com/thealgorithms/misc/WordBoggle.java    |  8 ++-
 .../java/com/thealgorithms/others/Conway.java |  4 +-
 .../com/thealgorithms/others/Dijkstra.java    |  5 +-
 .../others/InsertDeleteInArray.java           |  2 +-
 .../thealgorithms/others/KochSnowflake.java   |  4 +-
 .../com/thealgorithms/others/Mandelbrot.java  |  2 +-
 .../com/thealgorithms/others/PageRank.java    |  2 +-
 .../others/RotateMatriceBy90Degree.java       |  2 +-
 .../com/thealgorithms/others/TopKWords.java   | 10 +++-
 .../PreemptivePriorityScheduling.java         |  5 +-
 .../searches/BreadthFirstSearch.java          |  6 ++-
 .../searches/HowManyTimesRotated.java         |  2 +-
 .../thealgorithms/searches/QuickSelect.java   |  5 +-
 .../searches/RecursiveBinarySearch.java       |  2 +-
 .../com/thealgorithms/searches/UnionFind.java |  4 +-
 .../com/thealgorithms/sorts/BubbleSort.java   |  6 +--
 .../com/thealgorithms/sorts/CircleSort.java   |  6 +--
 .../com/thealgorithms/sorts/CombSort.java     |  8 ++-
 .../com/thealgorithms/sorts/CountingSort.java |  6 ++-
 .../com/thealgorithms/sorts/GnomeSort.java    | 10 ++--
 .../thealgorithms/sorts/InsertionSort.java    | 12 ++---
 .../com/thealgorithms/sorts/LinkListSort.java |  3 +-
 .../sorts/MergeSortNoExtraSpace.java          |  2 +-
 .../com/thealgorithms/sorts/PancakeSort.java  |  8 ++-
 .../thealgorithms/sorts/PigeonholeSort.java   |  8 ++-
 .../com/thealgorithms/sorts/QuickSort.java    | 10 ++--
 .../com/thealgorithms/sorts/ShellSort.java    |  6 +--
 .../com/thealgorithms/sorts/SimpleSort.java   | 12 ++---
 .../com/thealgorithms/sorts/SwapSort.java     | 12 ++---
 .../thealgorithms/sorts/TopologicalSort.java  |  6 ++-
 .../stacks/DuplicateBrackets.java             |  3 +-
 .../com/thealgorithms/strings/Isomorphic.java |  5 +-
 .../LetterCombinationsOfPhoneNumber.java      |  4 +-
 .../AllPathsFromSourceToTargetTest.java       |  4 +-
 .../backtracking/ArrayCombinationTest.java    |  3 +-
 .../backtracking/CombinationTest.java         |  2 +-
 .../backtracking/MColoringTest.java           |  4 +-
 .../backtracking/MazeRecursionTest.java       |  2 +-
 .../backtracking/PermutationTest.java         |  3 +-
 .../bitmanipulation/HighestSetBitTest.java    |  4 +-
 .../IndexOfRightMostSetBitTest.java           |  2 +-
 .../bitmanipulation/IsEvenTest.java           |  2 +-
 .../bitmanipulation/IsPowerTwoTest.java       |  3 +-
 .../NonRepeatingNumberFinderTest.java         |  2 +-
 .../NumbersDifferentSignsTest.java            |  3 +-
 .../bitmanipulation/ReverseBitsTest.java      |  2 +-
 .../thealgorithms/ciphers/BlowfishTest.java   |  2 +-
 .../com/thealgorithms/ciphers/CaesarTest.java |  2 +-
 .../com/thealgorithms/ciphers/DESTest.java    |  2 +-
 .../thealgorithms/ciphers/PlayfairTest.java   |  2 +-
 .../conversions/BinaryToHexadecimalTest.java  |  2 +-
 .../conversions/BinaryToOctalTest.java        |  2 +-
 .../conversions/DecimalToHexaDecimalTest.java |  2 +-
 .../conversions/HexToOctTest.java             |  2 +-
 .../conversions/HexaDecimalToBinaryTest.java  |  2 +-
 .../conversions/IntegerToRomanTest.java       |  2 +-
 .../conversions/OctalToBinaryTest.java        |  2 +-
 .../conversions/OctalToDecimalTest.java       |  2 +-
 .../conversions/OctalToHexadecimalTest.java   |  2 +-
 .../buffers/CircularBufferTest.java           | 11 +++-
 .../datastructures/crdt/GCounterTest.java     |  4 +-
 .../datastructures/crdt/GSetTest.java         |  3 +-
 .../crdt/LWWElementSetTest.java               |  3 +-
 .../datastructures/crdt/ORSetTest.java        |  4 +-
 .../datastructures/crdt/PNCounterTest.java    |  4 +-
 .../datastructures/crdt/TwoPSetTest.java      |  3 +-
 .../graphs/BoruvkaAlgorithmTest.java          |  4 +-
 .../graphs/HamiltonianCycleTest.java          |  2 +-
 .../hashmap/HashMapCuckooHashingTest.java     |  5 +-
 .../GenericHashMapUsingArrayListTest.java     |  5 +-
 .../hashing/GenericHashMapUsingArrayTest.java |  5 +-
 .../hashmap/hashing/MajorityElementTest.java  |  2 +-
 .../hashmap/hashing/MapTest.java              |  5 +-
 .../lists/QuickSortLinkedListTest.java        |  3 +-
 .../lists/ReverseKGroupTest.java              |  3 +-
 .../lists/RotateSinglyLinkedListsTest.java    |  3 +-
 .../lists/SinglyLinkedListTest.java           |  5 +-
 .../datastructures/lists/SkipListTest.java    |  6 ++-
 .../trees/LazySegmentTreeTest.java            |  2 +-
 .../BinaryExponentiationTest.java             |  2 +-
 .../StrassenMatrixMultiplicationTest.java     |  2 +-
 .../dynamicprogramming/CatalanNumberTest.java |  2 +-
 .../KnapsackMemoizationTest.java              |  2 +-
 .../PartitionProblemTest.java                 |  3 +-
 .../dynamicprogramming/UniquePathsTests.java  |  3 +-
 .../WildcardMatchingTest.java                 |  3 +-
 .../ActivitySelectionTest.java                |  2 +-
 .../FractionalKnapsackTest.java               |  2 +-
 .../greedyalgorithms/JobSequencingTest.java   |  2 +-
 .../thealgorithms/io/BufferedReaderTest.java  |  2 +-
 .../com/thealgorithms/maths/AreaTest.java     |  4 +-
 .../maths/AutomorphicNumberTest.java          |  3 +-
 .../maths/CollatzConjectureTest.java          |  4 +-
 .../maths/DudeneyNumberTest.java              |  3 +-
 .../java/com/thealgorithms/maths/FFTTest.java |  3 +-
 .../maths/FastInverseSqrtTests.java           |  2 +-
 .../maths/HarshadNumberTest.java              |  3 +-
 .../maths/KaprekarNumbersTest.java            |  3 +-
 .../maths/LiouvilleLambdaFunctionTest.java    |  3 +-
 .../thealgorithms/maths/LongDivisionTest.java |  2 +-
 .../com/thealgorithms/maths/MeansTest.java    |  3 +-
 .../maths/MillerRabinPrimalityCheckTest.java  | 28 +++++-----
 .../maths/MobiusFunctionTest.java             |  3 +-
 .../maths/PascalTriangleTest.java             |  2 +-
 .../maths/PerfectNumberTest.java              |  3 +-
 .../maths/PowerUsingRecursionTest.java        |  2 +-
 .../maths/PrimeFactorizationTest.java         |  3 +-
 .../thealgorithms/maths/PronicNumberTest.java |  3 +-
 .../SumWithoutArithmeticOperatorsTest.java    |  2 +-
 .../com/thealgorithms/maths/VolumeTest.java   |  2 +-
 .../com/thealgorithms/misc/MapReduceTest.java |  2 +-
 .../misc/MedianOfMatrixtest.java              |  2 +-
 .../others/ArrayLeftRotationTest.java         |  2 +-
 .../thealgorithms/others/BestFitCPUTest.java  |  2 +-
 .../thealgorithms/others/CountCharTest.java   |  2 +-
 .../others/CountFriendsPairingTest.java       |  2 +-
 .../thealgorithms/others/FirstFitCPUTest.java |  2 +-
 .../others/KadaneAlogrithmTest.java           |  2 +-
 .../thealgorithms/others/LineSweepTest.java   |  4 +-
 .../others/LinkListSortTest.java              |  2 +-
 ...SumOfDistinctSubarraysWithLengthKTest.java |  2 +-
 .../others/NewManShanksPrimeTest.java         |  2 +-
 .../com/thealgorithms/others/NextFitTest.java |  2 +-
 .../thealgorithms/others/PasswordGenTest.java |  3 +-
 .../others/TestPrintMatrixInSpiralOrder.java  | 52 +++++++++---------
 .../thealgorithms/others/WorstFitCPUTest.java |  2 +-
 .../PreemptivePrioritySchedulingTest.java     |  6 ++-
 .../scheduling/RRSchedulingTest.java          |  2 +-
 .../scheduling/SJFSchedulingTest.java         |  3 +-
 .../searches/BinarySearch2dArrayTest.java     |  2 +-
 .../searches/BreadthFirstSearchTest.java      |  4 +-
 .../searches/DepthFirstSearchTest.java        |  4 +-
 .../searches/HowManyTimesRotatedTest.java     |  2 +-
 .../thealgorithms/searches/KMPSearchTest.java |  2 +-
 .../searches/PerfectBinarySearchTest.java     |  2 +-
 .../searches/QuickSelectTest.java             | 11 ++--
 .../searches/RecursiveBinarySearchTest.java   |  2 +-
 ...estSearchInARowAndColWiseSortedMatrix.java | 54 +++++++++----------
 .../sorts/BinaryInsertionSortTest.java        |  2 +-
 .../sorts/DutchNationalFlagSortTest.java      |  2 +-
 .../sorts/InsertionSortTest.java              |  3 +-
 .../sorts/SelectionSortTest.java              |  2 +-
 .../thealgorithms/sorts/SortUtilsTest.java    |  3 +-
 .../sorts/SortingAlgorithmTest.java           |  4 +-
 .../thealgorithms/sorts/StrandSortTest.java   |  2 +-
 .../sorts/TopologicalSortTest.java            |  4 +-
 .../stacks/StackPostfixNotationTest.java      |  3 +-
 .../strings/AlphabeticalTest.java             |  3 +-
 .../thealgorithms/strings/AnagramsTest.java   |  2 +-
 .../strings/CharacterSameTest.java            |  3 +-
 .../strings/CheckVowelsTest.java              |  3 +-
 .../strings/HorspoolSearchTest.java           |  3 +-
 .../thealgorithms/strings/IsomorphicTest.java |  3 +-
 .../LetterCombinationsOfPhoneNumberTest.java  |  5 +-
 .../com/thealgorithms/strings/LowerTest.java  |  2 +-
 .../com/thealgorithms/strings/MyAtoiTest.java |  2 +-
 .../thealgorithms/strings/PangramTest.java    |  3 +-
 .../thealgorithms/strings/RotationTest.java   |  2 +-
 .../strings/StringCompressionTest.java        |  2 +-
 .../com/thealgorithms/strings/UpperTest.java  |  2 +-
 .../strings/ValidParenthesesTest.java         |  2 +-
 .../thealgorithms/strings/WordLadderTest.java |  5 +-
 188 files changed, 480 insertions(+), 311 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index bff19ff79f17..f6ad3c22c57f 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -120,7 +120,7 @@
 
     <!-- Checks for imports                              -->
     <!-- See https://checkstyle.org/checks/imports/index.html -->
-    <!-- TODO <module name="AvoidStarImport"/> -->
+    <module name="AvoidStarImport"/>
     <module name="IllegalImport"/> <!-- defaults to sun.* packages -->
     <module name="RedundantImport"/>
     <module name="UnusedImports">
diff --git a/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java b/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
index 71bf012d2835..a21f8c05f292 100644
--- a/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
+++ b/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
@@ -8,7 +8,8 @@
 /**Wikipedia link -> https://en.wikipedia.org/wiki/Shortest_path_problem */
 package com.thealgorithms.backtracking;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.List;
 
 public class AllPathsFromSourceToTarget {
 
diff --git a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
index ed5a0c933226..a25bf51de898 100644
--- a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
+++ b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.backtracking;
 
-import java.util.*;
+import java.util.List;
+import java.util.TreeSet;
 
 /**
  * Finds all permutations of 1...n of length k
diff --git a/src/main/java/com/thealgorithms/backtracking/Combination.java b/src/main/java/com/thealgorithms/backtracking/Combination.java
index 4b44a46d8595..3908da43b36a 100644
--- a/src/main/java/com/thealgorithms/backtracking/Combination.java
+++ b/src/main/java/com/thealgorithms/backtracking/Combination.java
@@ -1,6 +1,9 @@
 package com.thealgorithms.backtracking;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.TreeSet;
 
 /**
  * Finds all permutations of given array
diff --git a/src/main/java/com/thealgorithms/backtracking/KnightsTour.java b/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
index 6b3ec78a435a..694f4ad18b08 100644
--- a/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
+++ b/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.backtracking;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
 
 /*
     * Problem Statement: -
diff --git a/src/main/java/com/thealgorithms/backtracking/MColoring.java b/src/main/java/com/thealgorithms/backtracking/MColoring.java
index 93b17941566a..d7d0a1d2f36b 100644
--- a/src/main/java/com/thealgorithms/backtracking/MColoring.java
+++ b/src/main/java/com/thealgorithms/backtracking/MColoring.java
@@ -1,6 +1,10 @@
 package com.thealgorithms.backtracking;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.Queue;
+import java.util.Set;
 
 /**
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
diff --git a/src/main/java/com/thealgorithms/ciphers/AESEncryption.java b/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
index 169fc10e5269..92c1f6f5a4fd 100644
--- a/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
+++ b/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
@@ -3,7 +3,12 @@
 import java.security.InvalidAlgorithmParameterException;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
-import javax.crypto.*;
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.KeyGenerator;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.SecretKey;
 import javax.crypto.spec.GCMParameterSpec;
 
 /**
diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java b/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
index 011b60a952b8..9980d6deb8fc 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.conversions;
 
-import java.util.*;
+import java.util.HashMap;
+import java.util.Scanner;
 
 /**
  * Converts any Binary Number to a Hexadecimal Number
diff --git a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
index 19535df72d67..1338ba9bb8ef 100644
--- a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
+++ b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.conversions;
 
-import java.util.*;
+import java.util.HashMap;
+import java.util.Map;
 
 public class RomanToInteger {
 
diff --git a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
index f6f0276e0c35..e1697f44cacb 100644
--- a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
@@ -1,6 +1,10 @@
 package com.thealgorithms.datastructures.dynamicarray;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.ConcurrentModificationException;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.Objects;
 import java.util.function.Consumer;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java b/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
index 6d02afbeb652..0da876148e43 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
@@ -3,7 +3,11 @@
  */
 package com.thealgorithms.datastructures.graphs;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+import java.util.PriorityQueue;
 
 public class A_Star {
 
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
index 3251b7365b67..b4420b3e62d9 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.datastructures.graphs;
 
-import java.util.*;
+import java.util.Scanner;
 
 class BellmanFord /*
                    * Implementation of Bellman ford to detect negative cycles. Graph accepts
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java
index 23c26cfd0aab..d546b7cc88d4 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.heaps;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.HashMap;
 
 public class GenericHeap<T extends Comparable<T>> {
 
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java b/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
index 114a22d4b8c8..3309ab24917d 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
@@ -1,6 +1,11 @@
 package com.thealgorithms.datastructures.lists;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+import java.util.Random;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java
index f7afb60ac348..3820345b95bf 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java
@@ -1,6 +1,10 @@
 package com.thealgorithms.datastructures.trees;
 
-import java.util.*;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.List;
 
 /**
  * Given tree is traversed in a 'post-order' way: LEFT -> RIGHT -> ROOT.
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java
index d5bfd68e97e4..50158b0fae0a 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java
@@ -1,6 +1,10 @@
 package com.thealgorithms.datastructures.trees;
 
-import java.util.*;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.List;
 
 /**
  * Given a binary tree.
diff --git a/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java b/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
index 79b0dafad8f4..53661511aed5 100644
--- a/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
+++ b/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import java.util.*;
+import java.util.Scanner;
 
 /*
  * @author Ojasva Jain
diff --git a/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java b/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
index d2283dc10214..e46a3ac8374d 100644
--- a/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
+++ b/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
@@ -1,7 +1,8 @@
 package com.thealgorithms.maths;
 
 import java.math.BigInteger;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.List;
 
 public class KaprekarNumbers {
 
diff --git a/src/main/java/com/thealgorithms/maths/KeithNumber.java b/src/main/java/com/thealgorithms/maths/KeithNumber.java
index 1db9f9500ed1..fdabbc16685d 100644
--- a/src/main/java/com/thealgorithms/maths/KeithNumber.java
+++ b/src/main/java/com/thealgorithms/maths/KeithNumber.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Scanner;
 
 class KeithNumber {
 
diff --git a/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java b/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
index eacc75c23058..f152b0666a10 100644
--- a/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
@@ -5,7 +5,9 @@
 to the number itself. For example, 1, 2 and 145 are Krishnamurthy numbers. Krishnamurthy number is
 also referred to as a Strong number.
  */
-import java.io.*;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
 
 public class KrishnamurthyNumber {
 
diff --git a/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java b/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
index f4f7c94aa3e2..66352568f96d 100644
--- a/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
+++ b/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import java.util.*;
+import java.util.Scanner;
 
 /**
  * Is a common mathematics concept to find the smallest value number
diff --git a/src/main/java/com/thealgorithms/maths/MagicSquare.java b/src/main/java/com/thealgorithms/maths/MagicSquare.java
index 3bcede960346..6e9f88a5a0b9 100644
--- a/src/main/java/com/thealgorithms/maths/MagicSquare.java
+++ b/src/main/java/com/thealgorithms/maths/MagicSquare.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import java.util.*;
+import java.util.Scanner;
 
 /*A magic square of order n is an arrangement of distinct n^2 integers,in a square, such that the n
 numbers in all rows, all columns, and both diagonals sum to the same constant. A magic square
diff --git a/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java b/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
index d0d543d33966..f70a443e96e4 100644
--- a/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
+++ b/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.misc;
 
-import java.util.*;
+import java.util.Arrays;
 
 public class RangeInSortedArray {
 
diff --git a/src/main/java/com/thealgorithms/misc/Sort012D.java b/src/main/java/com/thealgorithms/misc/Sort012D.java
index 2ffe31b9ddd8..a311dac447ed 100644
--- a/src/main/java/com/thealgorithms/misc/Sort012D.java
+++ b/src/main/java/com/thealgorithms/misc/Sort012D.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.misc;
 
-import java.util.*;
+import java.util.Scanner;
 
 /**
  * The array is divided into four sections: a[1..Lo-1] zeroes a[Lo..Mid-1] ones
diff --git a/src/main/java/com/thealgorithms/misc/Sparcity.java b/src/main/java/com/thealgorithms/misc/Sparcity.java
index 7eb5e5896308..10b6f58096c3 100644
--- a/src/main/java/com/thealgorithms/misc/Sparcity.java
+++ b/src/main/java/com/thealgorithms/misc/Sparcity.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.misc;
 
-import java.util.*;
+import java.util.Scanner;
 
 /*
  *A matrix is sparse if many of its coefficients are zero (In general if 2/3rd of matrix elements
diff --git a/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java b/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
index a232ad986970..e5999313aa90 100644
--- a/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
+++ b/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
@@ -1,6 +1,14 @@
 package com.thealgorithms.misc;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Scanner;
+import java.util.Set;
 
 public class ThreeSumProblem {
 
diff --git a/src/main/java/com/thealgorithms/misc/WordBoggle.java b/src/main/java/com/thealgorithms/misc/WordBoggle.java
index 5b3b8f86af10..b56b907de935 100644
--- a/src/main/java/com/thealgorithms/misc/WordBoggle.java
+++ b/src/main/java/com/thealgorithms/misc/WordBoggle.java
@@ -1,6 +1,12 @@
 package com.thealgorithms.misc;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
 
 public class WordBoggle {
 
diff --git a/src/main/java/com/thealgorithms/others/Conway.java b/src/main/java/com/thealgorithms/others/Conway.java
index db1c102f8270..4ae4d7418fb4 100644
--- a/src/main/java/com/thealgorithms/others/Conway.java
+++ b/src/main/java/com/thealgorithms/others/Conway.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.others;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 
 public class Conway {
 
diff --git a/src/main/java/com/thealgorithms/others/Dijkstra.java b/src/main/java/com/thealgorithms/others/Dijkstra.java
index 3218c7bf43de..172e151f79a2 100644
--- a/src/main/java/com/thealgorithms/others/Dijkstra.java
+++ b/src/main/java/com/thealgorithms/others/Dijkstra.java
@@ -15,7 +15,10 @@
  * https://rosettacode.org/wiki/Dijkstra%27s_algorithm#Java Also most of the
  * comments are from RosettaCode.
  */
-import java.util.*;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.NavigableSet;
+import java.util.TreeSet;
 
 public class Dijkstra {
 
diff --git a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
index 201c0ad2dd80..d394ae102130 100644
--- a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
+++ b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import java.util.*;
+import java.util.Scanner;
 
 public class InsertDeleteInArray {
 
diff --git a/src/main/java/com/thealgorithms/others/KochSnowflake.java b/src/main/java/com/thealgorithms/others/KochSnowflake.java
index 04abc2dd8993..a87eedebee73 100644
--- a/src/main/java/com/thealgorithms/others/KochSnowflake.java
+++ b/src/main/java/com/thealgorithms/others/KochSnowflake.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.others;
 
-import java.awt.*;
+import java.awt.BasicStroke;
+import java.awt.Color;
+import java.awt.Graphics2D;
 import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.IOException;
diff --git a/src/main/java/com/thealgorithms/others/Mandelbrot.java b/src/main/java/com/thealgorithms/others/Mandelbrot.java
index e60d5c02ccaf..15618495646f 100644
--- a/src/main/java/com/thealgorithms/others/Mandelbrot.java
+++ b/src/main/java/com/thealgorithms/others/Mandelbrot.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import java.awt.*;
+import java.awt.Color;
 import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.IOException;
diff --git a/src/main/java/com/thealgorithms/others/PageRank.java b/src/main/java/com/thealgorithms/others/PageRank.java
index fa85e9700d3f..faade993cccc 100644
--- a/src/main/java/com/thealgorithms/others/PageRank.java
+++ b/src/main/java/com/thealgorithms/others/PageRank.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import java.util.*;
+import java.util.Scanner;
 
 class PageRank {
 
diff --git a/src/main/java/com/thealgorithms/others/RotateMatriceBy90Degree.java b/src/main/java/com/thealgorithms/others/RotateMatriceBy90Degree.java
index e2b47f8e627d..c9ebc45483aa 100644
--- a/src/main/java/com/thealgorithms/others/RotateMatriceBy90Degree.java
+++ b/src/main/java/com/thealgorithms/others/RotateMatriceBy90Degree.java
@@ -4,7 +4,7 @@
  * Given a matrix of size n x n We have to rotate this matrix by 90 Degree Here
  * is the algorithm for this problem .
  */
-import java.util.*;
+import java.util.Scanner;
 
 class Rotate_by_90_degree {
 
diff --git a/src/main/java/com/thealgorithms/others/TopKWords.java b/src/main/java/com/thealgorithms/others/TopKWords.java
index 43e71173d096..bb84d3f767e3 100644
--- a/src/main/java/com/thealgorithms/others/TopKWords.java
+++ b/src/main/java/com/thealgorithms/others/TopKWords.java
@@ -1,7 +1,13 @@
 package com.thealgorithms.others;
 
-import java.io.*;
-import java.util.*;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Scanner;
 
 /* display the most frequent K words in the file and the times it appear
 in the file – shown in order (ignore case and periods) */
diff --git a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
index 4523f6824410..f4ab56636266 100644
--- a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
@@ -1,6 +1,9 @@
 package com.thealgorithms.scheduling;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.PriorityQueue;
 
 /**
  * Preemptive Priority Scheduling Algorithm
diff --git a/src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java b/src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java
index 77043a03ffa3..debab98c67a8 100644
--- a/src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java
+++ b/src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java
@@ -1,7 +1,11 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.datastructures.Node;
-import java.util.*;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.Queue;
 
 /**
  * @author: caos321
diff --git a/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java b/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java
index dea0db37b3e5..350a3a6fede1 100644
--- a/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java
+++ b/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.searches;
 
-import java.util.*;
+import java.util.Scanner;
 
 /*
     Problem Statement:
diff --git a/src/main/java/com/thealgorithms/searches/QuickSelect.java b/src/main/java/com/thealgorithms/searches/QuickSelect.java
index 7d3e2e343961..f5ed7f71c9ed 100644
--- a/src/main/java/com/thealgorithms/searches/QuickSelect.java
+++ b/src/main/java/com/thealgorithms/searches/QuickSelect.java
@@ -1,6 +1,9 @@
 package com.thealgorithms.searches;
 
-import java.util.*;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Objects;
 
 /**
  * An implementation of the Quickselect algorithm as described
diff --git a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
index 8860f3380e31..6c6284e28019 100644
--- a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
@@ -4,7 +4,7 @@
 // Explanation:- https://www.tutorialspoint.com/java-program-for-binary-search-recursive
 package com.thealgorithms.searches;
 
-import java.util.*;
+import java.util.Scanner;
 
 // Create a SearchAlgorithm class with a generic type
 abstract class SearchAlgorithm<T extends Comparable<T>> {
diff --git a/src/main/java/com/thealgorithms/searches/UnionFind.java b/src/main/java/com/thealgorithms/searches/UnionFind.java
index 20f524785f28..fc5dbd801ffa 100644
--- a/src/main/java/com/thealgorithms/searches/UnionFind.java
+++ b/src/main/java/com/thealgorithms/searches/UnionFind.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.searches;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 
 public class UnionFind {
 
diff --git a/src/main/java/com/thealgorithms/sorts/BubbleSort.java b/src/main/java/com/thealgorithms/sorts/BubbleSort.java
index 46f30291d346..6823c68d0a74 100644
--- a/src/main/java/com/thealgorithms/sorts/BubbleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BubbleSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
 /**
  * @author Varun Upadhyay (https://github.com/varunu28)
  * @author Podshivalov Nikita (https://github.com/nikitap492)
@@ -21,8 +19,8 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         for (int i = 1, size = array.length; i < size; ++i) {
             boolean swapped = false;
             for (int j = 0; j < size - i; ++j) {
-                if (greater(array[j], array[j + 1])) {
-                    swap(array, j, j + 1);
+                if (SortUtils.greater(array[j], array[j + 1])) {
+                    SortUtils.swap(array, j, j + 1);
                     swapped = true;
                 }
             }
diff --git a/src/main/java/com/thealgorithms/sorts/CircleSort.java b/src/main/java/com/thealgorithms/sorts/CircleSort.java
index c6a6d9ea3658..756534a8ae4e 100644
--- a/src/main/java/com/thealgorithms/sorts/CircleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CircleSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
 public class CircleSort implements SortAlgorithm {
 
     /* This method implements the circle sort
@@ -35,7 +33,7 @@ private <T extends Comparable<T>> Boolean doSort(T[] array, int left, int right)
 
         while (low < high) {
             if (array[low].compareTo(array[high]) > 0) {
-                swap(array, low, high);
+                SortUtils.swap(array, low, high);
                 swapped = true;
             }
             low++;
@@ -43,7 +41,7 @@ private <T extends Comparable<T>> Boolean doSort(T[] array, int left, int right)
         }
 
         if (low == high && array[low].compareTo(array[high + 1]) > 0) {
-            swap(array, low, high + 1);
+            SortUtils.swap(array, low, high + 1);
             swapped = true;
         }
 
diff --git a/src/main/java/com/thealgorithms/sorts/CombSort.java b/src/main/java/com/thealgorithms/sorts/CombSort.java
index 2341ac652e83..edf09a2eb3f8 100644
--- a/src/main/java/com/thealgorithms/sorts/CombSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CombSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
 /**
  * Comb Sort algorithm implementation
  *
@@ -52,9 +50,9 @@ public <T extends Comparable<T>> T[] sort(T[] arr) {
 
             // Compare all elements with current gap
             for (int i = 0; i < size - gap; i++) {
-                if (less(arr[i + gap], arr[i])) {
+                if (SortUtils.less(arr[i + gap], arr[i])) {
                     // Swap arr[i] and arr[i+gap]
-                    swap(arr, i, i + gap);
+                    SortUtils.swap(arr, i, i + gap);
                     swapped = true;
                 }
             }
@@ -88,6 +86,6 @@ public static void main(String[] args) {
         ob.sort(arr);
 
         System.out.println("sorted array");
-        print(arr);
+        SortUtils.print(arr);
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/CountingSort.java b/src/main/java/com/thealgorithms/sorts/CountingSort.java
index 9a9b076b22e0..e83271d9ee67 100644
--- a/src/main/java/com/thealgorithms/sorts/CountingSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CountingSort.java
@@ -4,7 +4,11 @@
 import static java.util.stream.Collectors.toList;
 import static java.util.stream.Collectors.toMap;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 
diff --git a/src/main/java/com/thealgorithms/sorts/GnomeSort.java b/src/main/java/com/thealgorithms/sorts/GnomeSort.java
index 33a13d5bb2d4..9bef6a2837b5 100644
--- a/src/main/java/com/thealgorithms/sorts/GnomeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/GnomeSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
 /**
  * Implementation of gnome sort
  *
@@ -15,10 +13,10 @@ public <T extends Comparable<T>> T[] sort(T[] arr) {
         int i = 1;
         int j = 2;
         while (i < arr.length) {
-            if (less(arr[i - 1], arr[i])) {
+            if (SortUtils.less(arr[i - 1], arr[i])) {
                 i = j++;
             } else {
-                swap(arr, i - 1, i);
+                SortUtils.swap(arr, i - 1, i);
                 if (--i == 0) {
                     i = j++;
                 }
@@ -67,7 +65,7 @@ public static void main(String[] args) {
         gnomeSort.sort(strings);
 
         System.out.println("After sort : ");
-        print(integers);
-        print(strings);
+        SortUtils.print(integers);
+        SortUtils.print(strings);
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/InsertionSort.java b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
index cd160866ae15..285755c3fcbc 100644
--- a/src/main/java/com/thealgorithms/sorts/InsertionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
 import java.util.function.Function;
 
 class InsertionSort implements SortAlgorithm {
@@ -20,8 +18,8 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
 
     public <T extends Comparable<T>> T[] sort(T[] array, int lo, int hi) {
         for (int i = lo; i < hi; i++) {
-            for (int j = i; j > lo && less(array[j], array[j - 1]); j--) {
-                swap(array, j, j - 1);
+            for (int j = i; j > lo && SortUtils.less(array[j], array[j - 1]); j--) {
+                SortUtils.swap(array, j, j - 1);
             }
         }
         return array;
@@ -45,13 +43,13 @@ public <T extends Comparable<T>> T[] sentinelSort(T[] array) {
         // put the smallest element to the 0 position as a sentinel, which will allow us to avoid
         // redundant comparisons like `j > 0` further
         for (int i = 1; i < n; i++)
-            if (less(array[i], array[minElemIndex])) minElemIndex = i;
-        swap(array, 0, minElemIndex);
+            if (SortUtils.less(array[i], array[minElemIndex])) minElemIndex = i;
+        SortUtils.swap(array, 0, minElemIndex);
 
         for (int i = 2; i < n; i++) {
             int j = i;
             T currentValue = array[i];
-            while (less(currentValue, array[j - 1])) {
+            while (SortUtils.less(currentValue, array[j - 1])) {
                 array[j] = array[j - 1];
                 j--;
             }
diff --git a/src/main/java/com/thealgorithms/sorts/LinkListSort.java b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
index fb99439b949d..14f8394bac5b 100644
--- a/src/main/java/com/thealgorithms/sorts/LinkListSort.java
+++ b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
@@ -7,7 +7,8 @@
 
 package com.thealgorithms.sorts;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.Scanner;
 
 public class LinkListSort {
 
diff --git a/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java b/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
index b9551523bb8d..f235d2105b72 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
@@ -1,7 +1,7 @@
 package com.thealgorithms.sorts;
 
-import java.util.*;
 import java.util.Arrays;
+import java.util.Scanner;
 
 /*This code implements the mergeSort algorithm without extra space
 For understanding about mergesort visit :https://www.geeksforgeeks.org/merge-sort/
diff --git a/src/main/java/com/thealgorithms/sorts/PancakeSort.java b/src/main/java/com/thealgorithms/sorts/PancakeSort.java
index c5e59a0215b7..cd3e89307238 100644
--- a/src/main/java/com/thealgorithms/sorts/PancakeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/PancakeSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
 /**
  * Implementation of pancake sort
  *
@@ -18,12 +16,12 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
             T max = array[0];
             int index = 0;
             for (int j = 0; j < size - i; j++) {
-                if (less(max, array[j])) {
+                if (SortUtils.less(max, array[j])) {
                     max = array[j];
                     index = j;
                 }
             }
-            flip(array, index, array.length - 1 - i);
+            SortUtils.flip(array, index, array.length - 1 - i);
         }
         return array;
     }
@@ -62,6 +60,6 @@ public static void main(String[] args) {
         PancakeSort pancakeSort = new PancakeSort();
         System.out.println("After sorting:");
         pancakeSort.sort(arr);
-        print(arr);
+        SortUtils.print(arr);
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java b/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
index cd399fb701cb..9c0ab45b6a3c 100644
--- a/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
@@ -1,8 +1,6 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
-import java.util.*;
+import java.util.ArrayList;
 
 public class PigeonholeSort {
 
@@ -42,7 +40,7 @@ public static void main(String[] args) {
         Integer[] arr = {8, 3, 2, 7, 4, 6, 8};
 
         System.out.print("Unsorted order is : ");
-        print(arr);
+        SortUtils.print(arr);
 
         pigeonholeSort.sort(arr);
 
@@ -50,6 +48,6 @@ public static void main(String[] args) {
         for (int i = 0; i < arr.length; i++) {
             assert (arr[i]) <= (arr[i + 1]);
         }
-        print(arr);
+        SortUtils.print(arr);
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/QuickSort.java b/src/main/java/com/thealgorithms/sorts/QuickSort.java
index 2842b08a975c..3ebdd96ce938 100644
--- a/src/main/java/com/thealgorithms/sorts/QuickSort.java
+++ b/src/main/java/com/thealgorithms/sorts/QuickSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
 /**
  * @author Varun Upadhyay (https://github.com/varunu28)
  * @author Podshivalov Nikita (https://github.com/nikitap492)
@@ -45,7 +43,7 @@ private static <T extends Comparable<T>> void doSort(T[] array, int left, int ri
      */
     private static <T extends Comparable<T>> int randomPartition(T[] array, int left, int right) {
         int randomIndex = left + (int) (Math.random() * (right - left + 1));
-        swap(array, randomIndex, right);
+        SortUtils.swap(array, randomIndex, right);
         return partition(array, left, right);
     }
 
@@ -62,14 +60,14 @@ private static <T extends Comparable<T>> int partition(T[] array, int left, int
         T pivot = array[mid];
 
         while (left <= right) {
-            while (less(array[left], pivot)) {
+            while (SortUtils.less(array[left], pivot)) {
                 ++left;
             }
-            while (less(pivot, array[right])) {
+            while (SortUtils.less(pivot, array[right])) {
                 --right;
             }
             if (left <= right) {
-                swap(array, left, right);
+                SortUtils.swap(array, left, right);
                 ++left;
                 --right;
             }
diff --git a/src/main/java/com/thealgorithms/sorts/ShellSort.java b/src/main/java/com/thealgorithms/sorts/ShellSort.java
index 5f41a5440388..37a50e855698 100644
--- a/src/main/java/com/thealgorithms/sorts/ShellSort.java
+++ b/src/main/java/com/thealgorithms/sorts/ShellSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
 public class ShellSort implements SortAlgorithm {
 
     /**
@@ -25,7 +23,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
             for (int i = gap; i < length; i++) {
                 int j;
                 T temp = array[i];
-                for (j = i; j >= gap && less(temp, array[j - gap]); j -= gap) {
+                for (j = i; j >= gap && SortUtils.less(temp, array[j - gap]); j -= gap) {
                     array[j] = array[j - gap];
                 }
                 array[j] = temp;
@@ -43,6 +41,6 @@ public static void main(String[] args) {
         for (int i = 0; i < toSort.length - 1; ++i) {
             assert toSort[i] <= toSort[i + 1];
         }
-        print(toSort);
+        SortUtils.print(toSort);
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/SimpleSort.java b/src/main/java/com/thealgorithms/sorts/SimpleSort.java
index 138ebb62937d..e68b9a87acb2 100644
--- a/src/main/java/com/thealgorithms/sorts/SimpleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SimpleSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
 public class SimpleSort implements SortAlgorithm {
 
     @Override
@@ -10,7 +8,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
 
         for (int i = 0; i < LENGTH; i++) {
             for (int j = i + 1; j < LENGTH; j++) {
-                if (less(array[j], array[i])) {
+                if (SortUtils.less(array[j], array[i])) {
                     T element = array[j];
                     array[j] = array[i];
                     array[i] = element;
@@ -25,12 +23,12 @@ public static void main(String[] args) {
         // ==== Int =======
         Integer[] a = {3, 7, 45, 1, 33, 5, 2, 9};
         System.out.print("unsorted: ");
-        print(a);
+        SortUtils.print(a);
         System.out.println();
 
         new SimpleSort().sort(a);
         System.out.print("sorted: ");
-        print(a);
+        SortUtils.print(a);
         System.out.println();
 
         // ==== String =======
@@ -45,11 +43,11 @@ public static void main(String[] args) {
             "pineapple",
         };
         System.out.print("unsorted: ");
-        print(b);
+        SortUtils.print(b);
         System.out.println();
 
         new SimpleSort().sort(b);
         System.out.print("sorted: ");
-        print(b);
+        SortUtils.print(b);
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/SwapSort.java b/src/main/java/com/thealgorithms/sorts/SwapSort.java
index a626e511bb10..b10728b6a5c3 100644
--- a/src/main/java/com/thealgorithms/sorts/SwapSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SwapSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.*;
-
 /**
  * The idea of Swap-Sort is to count the number m of smaller values (that are in
  * A) from each element of an array A(1...n) and then swap the element with the
@@ -34,7 +32,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
     private <T extends Comparable<T>> int getSmallerElementCount(T[] array, int index) {
         int counter = 0;
         for (int i = 0; i < array.length; i++) {
-            if (less(array[i], array[index])) {
+            if (SortUtils.less(array[i], array[index])) {
                 counter++;
             }
         }
@@ -46,12 +44,12 @@ public static void main(String[] args) {
         // ==== Int =======
         Integer[] a = {3, 7, 45, 1, 33, 5, 2, 9};
         System.out.print("unsorted: ");
-        print(a);
+        SortUtils.print(a);
         System.out.println();
 
         new SwapSort().sort(a);
         System.out.print("sorted: ");
-        print(a);
+        SortUtils.print(a);
         System.out.println();
 
         // ==== String =======
@@ -66,11 +64,11 @@ public static void main(String[] args) {
             "pineapple",
         };
         System.out.print("unsorted: ");
-        print(b);
+        SortUtils.print(b);
         System.out.println();
 
         new SwapSort().sort(b);
         System.out.print("sorted: ");
-        print(b);
+        SortUtils.print(b);
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
index 1ba918275b7d..ac375e2a54f0 100644
--- a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
@@ -1,6 +1,10 @@
 package com.thealgorithms.sorts;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.LinkedList;
 
 /**
  * The Topological Sorting algorithm linearly orders a DAG or Directed Acyclic Graph into
diff --git a/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java b/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
index 7daf2e060e22..f78a24112d43 100644
--- a/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
+++ b/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
@@ -8,7 +8,8 @@
 // e.g.'
 // ((a + b) + (c + d)) -> false
 // (a + b) + ((c + d)) -> true
-import java.util.*;
+import java.util.Scanner;
+import java.util.Stack;
 
 public class DuplicateBrackets {
 
diff --git a/src/main/java/com/thealgorithms/strings/Isomorphic.java b/src/main/java/com/thealgorithms/strings/Isomorphic.java
index 7a355dcafa06..d7f436b0de75 100644
--- a/src/main/java/com/thealgorithms/strings/Isomorphic.java
+++ b/src/main/java/com/thealgorithms/strings/Isomorphic.java
@@ -1,6 +1,9 @@
 package com.thealgorithms.strings;
 
-import java.util.*;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
 
 public class Isomorphic {
 
diff --git a/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java b/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java
index 7ad9971eb56b..963684e4aff3 100644
--- a/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java
+++ b/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.strings;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 
 public class LetterCombinationsOfPhoneNumber {
 
diff --git a/src/test/java/com/thealgorithms/backtracking/AllPathsFromSourceToTargetTest.java b/src/test/java/com/thealgorithms/backtracking/AllPathsFromSourceToTargetTest.java
index cf702ccadecd..177163b09ca1 100644
--- a/src/test/java/com/thealgorithms/backtracking/AllPathsFromSourceToTargetTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/AllPathsFromSourceToTargetTest.java
@@ -1,8 +1,8 @@
 package com.thealgorithms.backtracking;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
 
-import java.util.*;
+import java.util.List;
 import org.junit.jupiter.api.Test;
 
 public class AllPathsFromSourceToTargetTest {
diff --git a/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java b/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java
index 02527257ccc6..23fa5d54574c 100644
--- a/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.backtracking;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 import java.util.List;
 import java.util.TreeSet;
diff --git a/src/test/java/com/thealgorithms/backtracking/CombinationTest.java b/src/test/java/com/thealgorithms/backtracking/CombinationTest.java
index ed6148271d91..44edc3077fd5 100644
--- a/src/test/java/com/thealgorithms/backtracking/CombinationTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/CombinationTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.backtracking;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
 import java.util.TreeSet;
diff --git a/src/test/java/com/thealgorithms/backtracking/MColoringTest.java b/src/test/java/com/thealgorithms/backtracking/MColoringTest.java
index 606193b05197..8b505abbc046 100644
--- a/src/test/java/com/thealgorithms/backtracking/MColoringTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/MColoringTest.java
@@ -1,8 +1,8 @@
 package com.thealgorithms.backtracking;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.util.*;
+import java.util.ArrayList;
 import org.junit.jupiter.api.Test;
 
 /**
diff --git a/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java b/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java
index 1464c5221bff..edaca14af067 100644
--- a/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.backtracking;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/backtracking/PermutationTest.java b/src/test/java/com/thealgorithms/backtracking/PermutationTest.java
index b6c0400c623f..76a714829109 100644
--- a/src/test/java/com/thealgorithms/backtracking/PermutationTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/PermutationTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.backtracking;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.Arrays;
 import java.util.List;
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java b/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java
index 8dc61ae4fa9d..532f06f79ab3 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.bitmanipulation;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java b/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java
index 56e9108cbc4b..9bf804373438 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.bitmanipulation;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java b/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java
index 2e33539fe4a7..674b79e57a08 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.bitmanipulation;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java b/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java
index 6954619806f6..27bc93c31ae4 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.bitmanipulation;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java b/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
index f0f7353a3365..c5031d976306 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.bitmanipulation;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java
index 31ab24826783..13761ac23e44 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java
@@ -5,7 +5,8 @@
  * @author Bama Charan Chhandogi
  */
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java
index 730e345686b6..967a89a1ee97 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.bitmanipulation;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java b/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java
index e143850e1669..ef5e634f781b 100644
--- a/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.ciphers;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/ciphers/CaesarTest.java b/src/test/java/com/thealgorithms/ciphers/CaesarTest.java
index 5fa81f95fa49..7aa41c4cf423 100644
--- a/src/test/java/com/thealgorithms/ciphers/CaesarTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/CaesarTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.ciphers;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/ciphers/DESTest.java b/src/test/java/com/thealgorithms/ciphers/DESTest.java
index 834f7e195165..ddc643a6eb35 100644
--- a/src/test/java/com/thealgorithms/ciphers/DESTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/DESTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.ciphers;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java b/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java
index 5562241b48db..fa497e4682e8 100644
--- a/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.ciphers;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java b/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java
index 9e7f9f697c2a..5cbdf39acb27 100644
--- a/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java b/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java
index 39a7f67024f1..c7018daecf23 100644
--- a/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/conversions/DecimalToHexaDecimalTest.java b/src/test/java/com/thealgorithms/conversions/DecimalToHexaDecimalTest.java
index de2cb7e25ccd..1105f457504e 100644
--- a/src/test/java/com/thealgorithms/conversions/DecimalToHexaDecimalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/DecimalToHexaDecimalTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/conversions/HexToOctTest.java b/src/test/java/com/thealgorithms/conversions/HexToOctTest.java
index d6a9b6092628..5924aa31854b 100644
--- a/src/test/java/com/thealgorithms/conversions/HexToOctTest.java
+++ b/src/test/java/com/thealgorithms/conversions/HexToOctTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java b/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java
index a5abcb95cb8d..72a0a0174a93 100644
--- a/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java
+++ b/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java b/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java
index 046b00754c4c..04768d034b93 100644
--- a/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java
+++ b/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java b/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java
index 6c7fe8702b68..86cf692c5258 100644
--- a/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java
+++ b/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java b/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java
index 4a4c6d84b053..6e17ea14efc8 100644
--- a/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java b/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java
index 347f0eb86fb5..f71732b27d51 100644
--- a/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java b/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
index 9158d0e12b5d..9bc3b89ced9e 100644
--- a/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
@@ -1,11 +1,18 @@
 package com.thealgorithms.datastructures.buffers;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
-import java.util.concurrent.*;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicIntegerArray;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.RepeatedTest;
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java
index f931e602383c..eb48c7d9e8d6 100644
--- a/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.datastructures.crdt;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java
index 74250ede1f23..b4566aa9b1d8 100644
--- a/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.crdt;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java
index 6fb227bd80c5..36593d6669f8 100644
--- a/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.crdt;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java
index f12c38f174dc..f6d19a3e7b20 100644
--- a/src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.datastructures.crdt;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.Set;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java
index 46c22a6edcb7..4081b8ae01d8 100644
--- a/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.datastructures.crdt;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java
index d81362e854d0..dfe392a0d616 100644
--- a/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.crdt;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
index b5f75f5e831e..579e236699b3 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.datastructures.graphs;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.datastructures.graphs.BoruvkaAlgorithm.Graph;
 import java.util.ArrayList;
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java
index 9890463de3ff..ed7c886d784e 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.datastructures.graphs;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java
index 851432006123..14bddeae1c91 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java
@@ -1,6 +1,9 @@
 package com.thealgorithms.datastructures.hashmap;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
 
 import com.thealgorithms.datastructures.hashmap.hashing.HashMapCuckooHashing;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java
index 621b353b85df..37e43d2aada3 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java
@@ -1,6 +1,9 @@
 package com.thealgorithms.datastructures.hashmap.hashing;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java
index b4443da153b4..483e43bb5cb3 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java
@@ -1,6 +1,9 @@
 package com.thealgorithms.datastructures.hashmap.hashing;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java
index df014510e8cd..49133ba5ffb5 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.datastructures.hashmap.hashing;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Collections;
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java
index ea6595cc803c..44551a8adac6 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java
@@ -1,6 +1,9 @@
 package com.thealgorithms.datastructures.hashmap.hashing;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.Random;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
index f4bcfd7fc40d..c4113b787de9 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
@@ -6,7 +6,8 @@
  * GitHub: https://github.com/Prabhat-Kumar-42
  */
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java b/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
index 8273b890e6ae..c03f5b14c641 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
@@ -5,7 +5,8 @@
  * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java b/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
index 23780758b664..d3c020f8881b 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
@@ -5,7 +5,8 @@
  * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
index bef02e62a929..30bd727e0169 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
@@ -1,6 +1,9 @@
 package com.thealgorithms.datastructures.lists;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.ArrayList;
 import java.util.Arrays;
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java
index 794b38d1502e..c572739ffbbf 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java
@@ -1,8 +1,10 @@
 package com.thealgorithms.datastructures.lists;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.util.*;
+import java.util.Arrays;
 import java.util.stream.IntStream;
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java
index 6df221280f86..e8294a323463 100644
--- a/src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.datastructures.trees;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java b/src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java
index bf1a60e84e77..ccada6e061e1 100644
--- a/src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java
+++ b/src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.divideandconquer;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java b/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
index 8331d8823486..6f4d4a09e442 100644
--- a/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
+++ b/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.divideandconquer;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java
index 8fbed8528bee..a065bb8c2a10 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.dynamicprogramming;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java
index b68e72931e71..34c0ab09225a 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.dynamicprogramming;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java
index d63c634c3969..098893f41771 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.dynamicprogramming;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java b/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java
index f6a86e72ad9c..f4e32f65af22 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.dynamicprogramming;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java
index 8d91af663ec5..56cd4ffe7d44 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.dynamicprogramming;
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
index 42263ac1de8a..106237ca041e 100644
--- a/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.greedyalgorithms;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Arrays;
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
index edbf0a09bcbd..e481128d9b6a 100644
--- a/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.greedyalgorithms;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java
index 8dd42bc7c5ec..b679121689a1 100644
--- a/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.greedyalgorithms;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Collections;
diff --git a/src/test/java/com/thealgorithms/io/BufferedReaderTest.java b/src/test/java/com/thealgorithms/io/BufferedReaderTest.java
index c9872980c3b7..baccf319d15e 100644
--- a/src/test/java/com/thealgorithms/io/BufferedReaderTest.java
+++ b/src/test/java/com/thealgorithms/io/BufferedReaderTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.io;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
diff --git a/src/test/java/com/thealgorithms/maths/AreaTest.java b/src/test/java/com/thealgorithms/maths/AreaTest.java
index 91fd03748163..b28afb85fbc3 100644
--- a/src/test/java/com/thealgorithms/maths/AreaTest.java
+++ b/src/test/java/com/thealgorithms/maths/AreaTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertAll;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/AutomorphicNumberTest.java b/src/test/java/com/thealgorithms/maths/AutomorphicNumberTest.java
index 9571efff1a42..0a366cd1adbe 100644
--- a/src/test/java/com/thealgorithms/maths/AutomorphicNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/AutomorphicNumberTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java b/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java
index 118e8db8726d..4e88d1e91bac 100644
--- a/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java
+++ b/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.List;
 import org.junit.jupiter.api.BeforeAll;
diff --git a/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java b/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java
index 09c8c4b1cc94..718a1def5eb8 100644
--- a/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/FFTTest.java b/src/test/java/com/thealgorithms/maths/FFTTest.java
index dfb9ea532dee..696ab5a24732 100644
--- a/src/test/java/com/thealgorithms/maths/FFTTest.java
+++ b/src/test/java/com/thealgorithms/maths/FFTTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
 
 import java.util.ArrayList;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java b/src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java
index 6e664f54307f..a3416a6bc871 100644
--- a/src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java
+++ b/src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java b/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java
index bea4e0a63d1f..af1c459f3d7f 100644
--- a/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java b/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java
index 52322e5558a9..05e58cf88e22 100644
--- a/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java
+++ b/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java b/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java
index a2be8a4c4954..a2763047acf0 100644
--- a/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java
+++ b/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/LongDivisionTest.java b/src/test/java/com/thealgorithms/maths/LongDivisionTest.java
index f0d702efa127..24f757f8f3ad 100644
--- a/src/test/java/com/thealgorithms/maths/LongDivisionTest.java
+++ b/src/test/java/com/thealgorithms/maths/LongDivisionTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/MeansTest.java b/src/test/java/com/thealgorithms/maths/MeansTest.java
index fa17cea68f7c..a1c07e25bea3 100644
--- a/src/test/java/com/thealgorithms/maths/MeansTest.java
+++ b/src/test/java/com/thealgorithms/maths/MeansTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.ArrayList;
 import java.util.LinkedHashSet;
diff --git a/src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java b/src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java
index 6e6fd491b989..d547cecf24cd 100644
--- a/src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java
+++ b/src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java
@@ -1,30 +1,30 @@
 package com.thealgorithms.maths;
 
-import static com.thealgorithms.maths.MillerRabinPrimalityCheck.*;
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
 class MillerRabinPrimalityCheckTest {
     @Test
     void testDeterministicMillerRabinForPrimes() {
-        assertTrue(deterministicMillerRabin(2));
-        assertTrue(deterministicMillerRabin(37));
-        assertTrue(deterministicMillerRabin(123457));
-        assertTrue(deterministicMillerRabin(6472601713L));
+        assertTrue(MillerRabinPrimalityCheck.deterministicMillerRabin(2));
+        assertTrue(MillerRabinPrimalityCheck.deterministicMillerRabin(37));
+        assertTrue(MillerRabinPrimalityCheck.deterministicMillerRabin(123457));
+        assertTrue(MillerRabinPrimalityCheck.deterministicMillerRabin(6472601713L));
     }
     @Test
     void testDeterministicMillerRabinForNotPrimes() {
-        assertFalse(deterministicMillerRabin(1));
-        assertFalse(deterministicMillerRabin(35));
-        assertFalse(deterministicMillerRabin(123453));
-        assertFalse(deterministicMillerRabin(647260175));
+        assertFalse(MillerRabinPrimalityCheck.deterministicMillerRabin(1));
+        assertFalse(MillerRabinPrimalityCheck.deterministicMillerRabin(35));
+        assertFalse(MillerRabinPrimalityCheck.deterministicMillerRabin(123453));
+        assertFalse(MillerRabinPrimalityCheck.deterministicMillerRabin(647260175));
     }
     @Test
     void testMillerRabinForPrimes() {
-        assertTrue(millerRabin(11, 5));
-        assertTrue(millerRabin(97, 5));
-        assertTrue(millerRabin(6720589, 5));
-        assertTrue(millerRabin(9549401549L, 5));
+        assertTrue(MillerRabinPrimalityCheck.millerRabin(11, 5));
+        assertTrue(MillerRabinPrimalityCheck.millerRabin(97, 5));
+        assertTrue(MillerRabinPrimalityCheck.millerRabin(6720589, 5));
+        assertTrue(MillerRabinPrimalityCheck.millerRabin(9549401549L, 5));
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java b/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java
index ddfac15d8200..f3a6514ce633 100644
--- a/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java
+++ b/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/PascalTriangleTest.java b/src/test/java/com/thealgorithms/maths/PascalTriangleTest.java
index 4f5ec4cef095..a1512aacb30d 100644
--- a/src/test/java/com/thealgorithms/maths/PascalTriangleTest.java
+++ b/src/test/java/com/thealgorithms/maths/PascalTriangleTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/PerfectNumberTest.java b/src/test/java/com/thealgorithms/maths/PerfectNumberTest.java
index 4dc7c8ce53ad..0433ba80cfa4 100644
--- a/src/test/java/com/thealgorithms/maths/PerfectNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/PerfectNumberTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java b/src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java
index 14574ab3c1eb..705cc6672818 100644
--- a/src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java
+++ b/src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java b/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java
index edc684481c2f..abe6068c2022 100644
--- a/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java
+++ b/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/maths/PronicNumberTest.java b/src/test/java/com/thealgorithms/maths/PronicNumberTest.java
index e4ca04fd0403..5a31981bed5c 100644
--- a/src/test/java/com/thealgorithms/maths/PronicNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/PronicNumberTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/SumWithoutArithmeticOperatorsTest.java b/src/test/java/com/thealgorithms/maths/SumWithoutArithmeticOperatorsTest.java
index 63f53bc6e0ba..1eab73c67642 100644
--- a/src/test/java/com/thealgorithms/maths/SumWithoutArithmeticOperatorsTest.java
+++ b/src/test/java/com/thealgorithms/maths/SumWithoutArithmeticOperatorsTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/VolumeTest.java b/src/test/java/com/thealgorithms/maths/VolumeTest.java
index 9692246b6a91..1bdb3ae80040 100644
--- a/src/test/java/com/thealgorithms/maths/VolumeTest.java
+++ b/src/test/java/com/thealgorithms/maths/VolumeTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/misc/MapReduceTest.java b/src/test/java/com/thealgorithms/misc/MapReduceTest.java
index 213acad9743b..c79c40701cc1 100644
--- a/src/test/java/com/thealgorithms/misc/MapReduceTest.java
+++ b/src/test/java/com/thealgorithms/misc/MapReduceTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.misc;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java b/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java
index c1fa30d6a1cd..ec3a84b86c5b 100644
--- a/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java
+++ b/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.misc;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Arrays;
diff --git a/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java b/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java
index 431d8daa2bab..355f107ddb61 100644
--- a/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java
+++ b/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/others/BestFitCPUTest.java b/src/test/java/com/thealgorithms/others/BestFitCPUTest.java
index 0a82ebdf011f..296cf1ca1c04 100644
--- a/src/test/java/com/thealgorithms/others/BestFitCPUTest.java
+++ b/src/test/java/com/thealgorithms/others/BestFitCPUTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Arrays;
diff --git a/src/test/java/com/thealgorithms/others/CountCharTest.java b/src/test/java/com/thealgorithms/others/CountCharTest.java
index 55e55b8d52f4..660f212118d2 100644
--- a/src/test/java/com/thealgorithms/others/CountCharTest.java
+++ b/src/test/java/com/thealgorithms/others/CountCharTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/others/CountFriendsPairingTest.java b/src/test/java/com/thealgorithms/others/CountFriendsPairingTest.java
index 070812f114d8..f2e6944c06d2 100644
--- a/src/test/java/com/thealgorithms/others/CountFriendsPairingTest.java
+++ b/src/test/java/com/thealgorithms/others/CountFriendsPairingTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.dynamicprogramming.CountFriendsPairing;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/others/FirstFitCPUTest.java b/src/test/java/com/thealgorithms/others/FirstFitCPUTest.java
index b726a746d5ac..57b6e189b116 100644
--- a/src/test/java/com/thealgorithms/others/FirstFitCPUTest.java
+++ b/src/test/java/com/thealgorithms/others/FirstFitCPUTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Arrays;
diff --git a/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java b/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java
index ac2aa9648c07..e5c0597d94c0 100644
--- a/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java
+++ b/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.dynamicprogramming.KadaneAlgorithm;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/others/LineSweepTest.java b/src/test/java/com/thealgorithms/others/LineSweepTest.java
index 20cf1cd75153..af23885b4a7e 100644
--- a/src/test/java/com/thealgorithms/others/LineSweepTest.java
+++ b/src/test/java/com/thealgorithms/others/LineSweepTest.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.others;
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 public class LineSweepTest {
diff --git a/src/test/java/com/thealgorithms/others/LinkListSortTest.java b/src/test/java/com/thealgorithms/others/LinkListSortTest.java
index e0e258aacd69..100593b1f756 100644
--- a/src/test/java/com/thealgorithms/others/LinkListSortTest.java
+++ b/src/test/java/com/thealgorithms/others/LinkListSortTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.sorts.LinkListSort;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java b/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
index 49855161ec90..26c57a1c9f75 100644
--- a/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
+++ b/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java b/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java
index 660562a5506e..3b657e441b1c 100644
--- a/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java
+++ b/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.dynamicprogramming.NewManShanksPrime;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/others/NextFitTest.java b/src/test/java/com/thealgorithms/others/NextFitTest.java
index 2de6b411080c..75fb3ab7c261 100644
--- a/src/test/java/com/thealgorithms/others/NextFitTest.java
+++ b/src/test/java/com/thealgorithms/others/NextFitTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Arrays;
diff --git a/src/test/java/com/thealgorithms/others/PasswordGenTest.java b/src/test/java/com/thealgorithms/others/PasswordGenTest.java
index aa5303ada239..57de329c8f09 100644
--- a/src/test/java/com/thealgorithms/others/PasswordGenTest.java
+++ b/src/test/java/com/thealgorithms/others/PasswordGenTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java b/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java
index 6cc653670a21..986e72ea45b5 100644
--- a/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java
+++ b/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java
@@ -1,26 +1,26 @@
-package com.thealgorithms.others;
-
-import static org.junit.jupiter.api.Assertions.*;
-
-import java.util.List;
-import org.junit.jupiter.api.Test;
-
-public class TestPrintMatrixInSpiralOrder {
-    @Test
-    public void testOne() {
-        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
-        var printClass = new PrintAMatrixInSpiralOrder();
-        List<Integer> res = printClass.print(matrix, matrix.length, matrix[0].length);
-        List<Integer> list = List.of(3, 4, 5, 6, 7, 12, 18, 27, 34, 33, 32, 31, 30, 23, 14, 8, 9, 10, 11, 17, 26, 25, 24, 15, 16);
-        assertIterableEquals(res, list);
-    }
-
-    @Test
-    public void testTwo() {
-        int[][] matrix = {{2, 2}};
-        var printClass = new PrintAMatrixInSpiralOrder();
-        List<Integer> res = printClass.print(matrix, matrix.length, matrix[0].length);
-        List<Integer> list = List.of(2, 2);
-        assertIterableEquals(res, list);
-    }
-}
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class TestPrintMatrixInSpiralOrder {
+    @Test
+    public void testOne() {
+        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
+        var printClass = new PrintAMatrixInSpiralOrder();
+        List<Integer> res = printClass.print(matrix, matrix.length, matrix[0].length);
+        List<Integer> list = List.of(3, 4, 5, 6, 7, 12, 18, 27, 34, 33, 32, 31, 30, 23, 14, 8, 9, 10, 11, 17, 26, 25, 24, 15, 16);
+        assertIterableEquals(res, list);
+    }
+
+    @Test
+    public void testTwo() {
+        int[][] matrix = {{2, 2}};
+        var printClass = new PrintAMatrixInSpiralOrder();
+        List<Integer> res = printClass.print(matrix, matrix.length, matrix[0].length);
+        List<Integer> list = List.of(2, 2);
+        assertIterableEquals(res, list);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java b/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java
index 6f2a53b3dfe7..eb69f6056132 100644
--- a/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java
+++ b/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Arrays;
diff --git a/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
index 5cb3c624db42..61e2a2ac2690 100644
--- a/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
@@ -5,9 +5,11 @@
  * @author [Bama Charan Chhandogi](https://www.github.com/BamaCharanChhandogi)
  */
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 import org.junit.jupiter.api.Test;
 
 class PreemptivePrioritySchedulingTest {
diff --git a/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java
index 700a174f328c..3da526601f5f 100644
--- a/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.scheduling;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import com.thealgorithms.devutils.entities.ProcessDetails;
 import java.util.ArrayList;
diff --git a/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java
index ae31feb9a6b4..41cbe75afbb5 100644
--- a/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.scheduling;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.devutils.entities.ProcessDetails;
 import java.util.ArrayList;
diff --git a/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java b/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java
index e5db2f74f446..ec834d788589 100644
--- a/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java
+++ b/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java
@@ -3,7 +3,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import java.util.*;
+import java.util.Arrays;
 import org.junit.jupiter.api.Test;
 
 public class BinarySearch2dArrayTest {
diff --git a/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java b/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java
index 77562ecdb87d..2a32a4ddb46c 100644
--- a/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.searches;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.datastructures.Node;
 import java.util.List;
diff --git a/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java b/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java
index f85e94090d3f..af21b570fd7c 100644
--- a/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.searches;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.datastructures.Node;
 import java.util.List;
diff --git a/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java b/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java
index ac731b0f5dea..7d52e9fb4eca 100644
--- a/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java
+++ b/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.searches;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/searches/KMPSearchTest.java b/src/test/java/com/thealgorithms/searches/KMPSearchTest.java
index a0250ba34f5a..ab6a14fbb604 100644
--- a/src/test/java/com/thealgorithms/searches/KMPSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/KMPSearchTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.searches;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
index ca5829c54495..6eab20f45467 100644
--- a/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.searches;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/searches/QuickSelectTest.java b/src/test/java/com/thealgorithms/searches/QuickSelectTest.java
index 405135ecad0d..dd04c85b76ae 100644
--- a/src/test/java/com/thealgorithms/searches/QuickSelectTest.java
+++ b/src/test/java/com/thealgorithms/searches/QuickSelectTest.java
@@ -1,8 +1,13 @@
 package com.thealgorithms.searches;
 
-import static org.junit.jupiter.api.Assertions.*;
-
-import java.util.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Random;
 import java.util.stream.Collectors;
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java
index 4144efa5e89b..0a2794f9e8d7 100644
--- a/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java
@@ -3,7 +3,7 @@
 // Test file updated with JUnit tests
 package com.thealgorithms.searches;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test; // Import the JUnit 5 Test annotation
 
diff --git a/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java b/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java
index 83e6562122ff..014fb4bd24af 100644
--- a/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java
+++ b/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java
@@ -1,27 +1,27 @@
-package com.thealgorithms.searches;
-
-import static org.junit.jupiter.api.Assertions.*;
-
-import org.junit.jupiter.api.Test;
-
-public class TestSearchInARowAndColWiseSortedMatrix {
-    @Test
-    public void searchItem() {
-        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
-
-        var test = new SearchInARowAndColWiseSortedMatrix();
-        int[] res = test.search(matrix, 16);
-        int[] expectedResult = {2, 2};
-        assertArrayEquals(expectedResult, res);
-    }
-
-    @Test
-    public void notFound() {
-        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
-
-        var test = new SearchInARowAndColWiseSortedMatrix();
-        int[] res = test.search(matrix, 96);
-        int[] expectedResult = {-1, -1};
-        assertArrayEquals(expectedResult, res);
-    }
-}
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class TestSearchInARowAndColWiseSortedMatrix {
+    @Test
+    public void searchItem() {
+        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
+
+        var test = new SearchInARowAndColWiseSortedMatrix();
+        int[] res = test.search(matrix, 16);
+        int[] expectedResult = {2, 2};
+        assertArrayEquals(expectedResult, res);
+    }
+
+    @Test
+    public void notFound() {
+        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
+
+        var test = new SearchInARowAndColWiseSortedMatrix();
+        int[] res = test.search(matrix, 96);
+        int[] expectedResult = {-1, -1};
+        assertArrayEquals(expectedResult, res);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java b/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
index 5261d6c64785..349c3a2b9bba 100644
--- a/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java b/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java
index 7c81aefc6d04..8d3a4ac4349c 100644
--- a/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java b/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java
index 87a2c73384c3..78744973355d 100644
--- a/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.function.Function;
 import org.junit.jupiter.api.BeforeEach;
diff --git a/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java b/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java
index 36470f86451d..a718f450071f 100644
--- a/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java b/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java
index 34a6b00dd9a8..591b53891ee7 100644
--- a/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java b/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java
index 92e743cf220c..113bff2b5b0d 100644
--- a/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.ArrayList;
 import java.util.List;
diff --git a/src/test/java/com/thealgorithms/sorts/StrandSortTest.java b/src/test/java/com/thealgorithms/sorts/StrandSortTest.java
index 679a1131f53f..4a0001a43647 100644
--- a/src/test/java/com/thealgorithms/sorts/StrandSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/StrandSortTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import java.util.Arrays;
 import java.util.LinkedList;
diff --git a/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java b/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
index e299dad1276a..9fb0fc06a002 100644
--- a/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import com.thealgorithms.sorts.TopologicalSort.BackEdgeException;
 import com.thealgorithms.sorts.TopologicalSort.Graph;
diff --git a/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java b/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java
index 4857529e49a5..a8d8e0d3d9dc 100644
--- a/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java
+++ b/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java
@@ -1,7 +1,8 @@
 package com.thealgorithms.stacks;
 
 import static java.util.Map.entry;
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.Map;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java b/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java
index 3d240f2c2bed..083239152ec2 100644
--- a/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java
+++ b/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/AnagramsTest.java b/src/test/java/com/thealgorithms/strings/AnagramsTest.java
index 2b56ef0172f9..ba530cffb017 100644
--- a/src/test/java/com/thealgorithms/strings/AnagramsTest.java
+++ b/src/test/java/com/thealgorithms/strings/AnagramsTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/CharacterSameTest.java b/src/test/java/com/thealgorithms/strings/CharacterSameTest.java
index e4faee25e84f..d91b5f2f55e9 100644
--- a/src/test/java/com/thealgorithms/strings/CharacterSameTest.java
+++ b/src/test/java/com/thealgorithms/strings/CharacterSameTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java b/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java
index 74918929f3c8..713b53f0b634 100644
--- a/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java
+++ b/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java b/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java
index f2faf49cfd3e..9649a89a3325 100644
--- a/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java
+++ b/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/IsomorphicTest.java b/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
index a51b0fe9caa9..4601404c7817 100644
--- a/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
+++ b/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java b/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java
index c9b890f4d502..4ffbddcb44a8 100644
--- a/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java
+++ b/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java
@@ -1,8 +1,9 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.List;
 import org.junit.jupiter.api.Test;
 
 public class LetterCombinationsOfPhoneNumberTest {
diff --git a/src/test/java/com/thealgorithms/strings/LowerTest.java b/src/test/java/com/thealgorithms/strings/LowerTest.java
index ebc72f3c7bfd..e0abb921a593 100644
--- a/src/test/java/com/thealgorithms/strings/LowerTest.java
+++ b/src/test/java/com/thealgorithms/strings/LowerTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/MyAtoiTest.java b/src/test/java/com/thealgorithms/strings/MyAtoiTest.java
index 6d27a8acb415..45f9158571e9 100644
--- a/src/test/java/com/thealgorithms/strings/MyAtoiTest.java
+++ b/src/test/java/com/thealgorithms/strings/MyAtoiTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/PangramTest.java b/src/test/java/com/thealgorithms/strings/PangramTest.java
index 7ad79b203b45..00ecb909b2de 100644
--- a/src/test/java/com/thealgorithms/strings/PangramTest.java
+++ b/src/test/java/com/thealgorithms/strings/PangramTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/RotationTest.java b/src/test/java/com/thealgorithms/strings/RotationTest.java
index 239366df92b2..911ff87d29ad 100644
--- a/src/test/java/com/thealgorithms/strings/RotationTest.java
+++ b/src/test/java/com/thealgorithms/strings/RotationTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/StringCompressionTest.java b/src/test/java/com/thealgorithms/strings/StringCompressionTest.java
index 4194cad0b754..bbd56c19dc23 100644
--- a/src/test/java/com/thealgorithms/strings/StringCompressionTest.java
+++ b/src/test/java/com/thealgorithms/strings/StringCompressionTest.java
@@ -1,5 +1,5 @@
 package com.thealgorithms.strings;
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
diff --git a/src/test/java/com/thealgorithms/strings/UpperTest.java b/src/test/java/com/thealgorithms/strings/UpperTest.java
index 5c030efdc740..5413c77b913a 100644
--- a/src/test/java/com/thealgorithms/strings/UpperTest.java
+++ b/src/test/java/com/thealgorithms/strings/UpperTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
index 13909e636f5c..6b7e04e972ea 100644
--- a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
+++ b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/strings/WordLadderTest.java b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
index 5b40df8b4d17..4f1d07ebdc4a 100644
--- a/src/test/java/com/thealgorithms/strings/WordLadderTest.java
+++ b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
@@ -1,8 +1,9 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.List;
 import org.junit.jupiter.api.Test;
 
 public class WordLadderTest {

From bfb27eeb59f5a0b63e40054448d6acf895c1901b Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 6 May 2024 21:49:52 +0200
Subject: [PATCH 0144/1338] style: enable `ArrayTypeStyle` in checkstyle
 (#5145)

---
 checkstyle.xml                                       |  2 +-
 src/main/java/com/thealgorithms/ciphers/DES.java     | 12 ++++++------
 .../NonRepeatingNumberFinderTest.java                |  6 +++---
 .../greedyalgorithms/ActivitySelectionTest.java      | 12 ++++++------
 .../greedyalgorithms/FractionalKnapsackTest.java     | 12 ++++++------
 5 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index f6ad3c22c57f..8424e07f2694 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -181,7 +181,7 @@
 
     <!-- Miscellaneous other checks.                   -->
     <!-- See https://checkstyle.org/checks/misc/index.html -->
-    <!-- TODO <module name="ArrayTypeStyle"/> -->
+    <module name="ArrayTypeStyle"/>
     <!-- TODO <module name="FinalParameters"/> -->
     <!-- TODO <module name="TodoComment"/> -->
     <module name="UpperEll"/>
diff --git a/src/main/java/com/thealgorithms/ciphers/DES.java b/src/main/java/com/thealgorithms/ciphers/DES.java
index 119ad69767e2..8e44f09131ae 100644
--- a/src/main/java/com/thealgorithms/ciphers/DES.java
+++ b/src/main/java/com/thealgorithms/ciphers/DES.java
@@ -8,7 +8,7 @@
 public class DES {
 
     private String key;
-    private String subKeys[];
+    private String[] subKeys;
 
     private void sanitize(String key) {
         int length = key.length();
@@ -78,7 +78,7 @@ private String[] getSubkeys(String originalKey) {
         for (i = 0; i < 56; i++) {
             permutedKey.append(originalKey.charAt(PC1[i] - 1));
         }
-        String subKeys[] = new String[16];
+        String[] subKeys = new String[16];
         String initialPermutedKey = permutedKey.toString();
         String C0 = initialPermutedKey.substring(0, 28), D0 = initialPermutedKey.substring(28);
 
@@ -159,7 +159,7 @@ private String feistel(String messageBlock, String key) {
         return permutedString.toString();
     }
 
-    private String encryptBlock(String message, String keys[]) {
+    private String encryptBlock(String message, String[] keys) {
         StringBuilder permutedMessage = new StringBuilder();
         int i;
         for (i = 0; i < 64; i++) {
@@ -184,8 +184,8 @@ private String encryptBlock(String message, String keys[]) {
     }
 
     // To decode, we follow the same process as encoding, but with reversed keys
-    private String decryptBlock(String message, String keys[]) {
-        String reversedKeys[] = new String[keys.length];
+    private String decryptBlock(String message, String[] keys) {
+        String[] reversedKeys = new String[keys.length];
         for (int i = 0; i < keys.length; i++) {
             reversedKeys[i] = keys[keys.length - i - 1];
         }
@@ -230,7 +230,7 @@ public String decrypt(String message) {
         for (i = 0; i < l; i += 64) {
             String block = message.substring(i, i + 64);
             String result = decryptBlock(block.toString(), subKeys);
-            byte res[] = new byte[8];
+            byte[] res = new byte[8];
             for (j = 0; j < 64; j += 8) {
                 res[j / 8] = (byte) Integer.parseInt(result.substring(j, j + 8), 2);
             }
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java b/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
index c5031d976306..1addde057181 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
@@ -13,11 +13,11 @@ class NonRepeatingNumberFinderTest {
 
     @Test
     void testNonRepeatingNumberFinder() {
-        int arr[] = {1, 2, 1, 2, 6};
+        int[] arr = {1, 2, 1, 2, 6};
         assertEquals(6, NonRepeatingNumberFinder.findNonRepeatingNumber(arr));
-        int arr1[] = {1, 2, 1, 2};
+        int[] arr1 = {1, 2, 1, 2};
         assertEquals(0, NonRepeatingNumberFinder.findNonRepeatingNumber(arr1));
-        int arr2[] = {12};
+        int[] arr2 = {12};
         assertEquals(12, NonRepeatingNumberFinder.findNonRepeatingNumber(arr2));
     }
 }
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
index 106237ca041e..a997c198a39b 100644
--- a/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
@@ -9,8 +9,8 @@
 public class ActivitySelectionTest {
     @Test
     public void testActivitySelection() {
-        int start[] = {1, 3, 0, 5, 8, 5};
-        int end[] = {2, 4, 6, 7, 9, 9};
+        int[] start = {1, 3, 0, 5, 8, 5};
+        int[] end = {2, 4, 6, 7, 9, 9};
 
         ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
         ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0, 1, 3, 4));
@@ -20,8 +20,8 @@ public void testActivitySelection() {
 
     @Test
     public void testSingleActivity() {
-        int start[] = {1};
-        int end[] = {2};
+        int[] start = {1};
+        int[] end = {2};
 
         ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
         ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0));
@@ -31,8 +31,8 @@ public void testSingleActivity() {
 
     @Test
     public void testNoOverlap() {
-        int start[] = {1, 2, 3};
-        int end[] = {2, 3, 4};
+        int[] start = {1, 2, 3};
+        int[] end = {2, 3, 4};
 
         ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
         ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0, 1, 2));
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
index e481128d9b6a..34ec354ba6f0 100644
--- a/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
@@ -8,24 +8,24 @@ public class FractionalKnapsackTest {
 
     @Test
     public void testFractionalKnapsackWithExampleCase() {
-        int weight[] = {10, 20, 30};
-        int value[] = {60, 100, 120};
+        int[] weight = {10, 20, 30};
+        int[] value = {60, 100, 120};
         int capacity = 50;
         assertEquals(240, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
     }
 
     @Test
     public void testFractionalKnapsackWithZeroCapacity() {
-        int weight[] = {10, 20, 30};
-        int value[] = {60, 100, 120};
+        int[] weight = {10, 20, 30};
+        int[] value = {60, 100, 120};
         int capacity = 0;
         assertEquals(0, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
     }
 
     @Test
     public void testFractionalKnapsackWithEmptyItems() {
-        int weight[] = {};
-        int value[] = {};
+        int[] weight = {};
+        int[] value = {};
         int capacity = 50;
         assertEquals(0, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
     }

From ff5267d3938edc8312dfb4a3245f8387a7b1210c Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 7 May 2024 07:44:37 +0200
Subject: [PATCH 0145/1338] Chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.8.4.0 to 4.8.5.0 (#5146)

Chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.8.4.0 to 4.8.5.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.8.4.0...spotbugs-maven-plugin-4.8.5.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b8a7e22a45cf..036350d7b3dd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -117,7 +117,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.8.4.0</version>
+                <version>4.8.5.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 030bb91d0556a0527e079239a8f43c75f03dc9f6 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 7 May 2024 20:29:11 +0200
Subject: [PATCH 0146/1338] chore: configure SpotBugs plugin `find-sec-bugs`
 (#5144)

---
 pom.xml              |  5 +++++
 spotbugs-exclude.xml | 10 ++++++++++
 2 files changed, 15 insertions(+)

diff --git a/pom.xml b/pom.xml
index 036350d7b3dd..738461cc6f4d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -127,6 +127,11 @@
                             <artifactId>fb-contrib</artifactId>
                             <version>7.6.4</version>
                         </plugin>
+                        <plugin>
+                            <groupId>com.h3xstream.findsecbugs</groupId>
+                            <artifactId>findsecbugs-plugin</artifactId>
+                            <version>1.13.0</version>
+                        </plugin>
                     </plugins>
                 </configuration>
             </plugin>
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 4ef8fe8de448..97c4e760eb6f 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -282,4 +282,14 @@
     <Match>
         <Bug pattern="SPP_TOSTRING_ON_STRING" />
     </Match>
+    <!-- find-sec-bugs -->
+    <Match>
+        <Bug pattern="PREDICTABLE_RANDOM" />
+    </Match>
+    <Match>
+        <Bug pattern="HARD_CODE_KEY" />
+    </Match>
+    <Match>
+        <Bug pattern="PATH_TRAVERSAL_IN" />
+    </Match>
 </FindBugsFilter>

From d3bb691f59fe118616df97588216cb4d03fe3be3 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 8 May 2024 08:58:29 +0200
Subject: [PATCH 0147/1338] style: enable `HideUtilityClassConstructor` in
 checkstyle (#5147)

---
 checkstyle.xml                                |  2 +-
 .../backtracking/ArrayCombination.java        |  4 +-
 .../backtracking/Combination.java             |  4 +-
 .../backtracking/KnightsTour.java             |  4 +-
 .../thealgorithms/backtracking/MColoring.java |  4 +-
 .../backtracking/MazeRecursion.java           |  4 +-
 .../thealgorithms/backtracking/NQueens.java   |  4 +-
 .../backtracking/Permutation.java             |  4 +-
 .../IndexOfRightMostSetBit.java               |  4 +-
 .../thealgorithms/bitmanipulation/IsEven.java |  4 +-
 .../bitmanipulation/IsPowerTwo.java           |  4 +-
 .../NonRepeatingNumberFinder.java             |  4 +-
 .../NumbersDifferentSigns.java                |  4 +-
 .../bitmanipulation/ReverseBits.java          |  4 +-
 .../java/com/thealgorithms/ciphers/AES.java   |  4 +-
 .../thealgorithms/ciphers/AESEncryption.java  |  4 +-
 .../thealgorithms/ciphers/AffineCipher.java   |  4 +-
 .../ciphers/ColumnarTranspositionCipher.java  |  4 +-
 .../com/thealgorithms/ciphers/HillCipher.java |  4 +-
 .../com/thealgorithms/ciphers/Polybius.java   |  4 +-
 .../thealgorithms/ciphers/ProductCipher.java  |  4 +-
 .../com/thealgorithms/ciphers/a5/Utils.java   |  4 +-
 .../conversions/AnyBaseToAnyBase.java         |  4 +-
 .../conversions/AnyBaseToDecimal.java         |  4 +-
 .../thealgorithms/conversions/AnytoAny.java   |  4 +-
 .../conversions/BinaryToDecimal.java          |  4 +-
 .../conversions/BinaryToHexadecimal.java      |  4 +-
 .../conversions/BinaryToOctal.java            |  4 +-
 .../conversions/DecimalToAnyBase.java         |  4 +-
 .../conversions/DecimalToBinary.java          |  4 +-
 .../conversions/DecimalToHexaDecimal.java     |  4 +-
 .../conversions/DecimalToOctal.java           |  4 +-
 .../thealgorithms/conversions/HexToOct.java   |  4 +-
 .../conversions/HexaDecimalToDecimal.java     |  4 +-
 .../conversions/IntegerToRoman.java           |  4 +-
 .../conversions/OctalToBinary.java            |  4 +-
 .../conversions/OctalToDecimal.java           |  4 +-
 .../conversions/OctalToHexadecimal.java       |  4 +-
 .../conversions/RgbHsvConversion.java         |  4 +-
 .../conversions/RomanToInteger.java           |  4 +-
 .../conversions/TurkishToLatinConversion.java |  4 +-
 .../datastructures/graphs/A_Star.java         |  4 +-
 .../graphs/BipartiteGrapfDFS.java             |  4 +-
 .../graphs/ConnectedComponent.java            |  4 +-
 .../datastructures/graphs/Cycles.java         |  4 +-
 .../datastructures/graphs/Graphs.java         |  4 +-
 .../datastructures/graphs/KahnsAlgorithm.java |  4 +-
 .../datastructures/graphs/MatrixGraphs.java   |  4 +-
 .../datastructures/hashmap/hashing/Main.java  |  4 +-
 .../hashmap/hashing/MainCuckooHashing.java    |  4 +-
 .../hashmap/hashing/MajorityElement.java      |  4 +-
 .../lists/CreateAndDetectLoop.java            |  4 +-
 .../lists/MergeSortedArrayList.java           |  4 +-
 .../datastructures/queues/Queues.java         |  4 +-
 .../datastructures/stacks/ReverseStack.java   |  4 +-
 .../stacks/StackOfLinkedList.java             |  4 +-
 .../trees/BSTFromSortedArray.java             |  4 +-
 .../trees/CeilInBinarySearchTree.java         |  4 +-
 .../trees/CheckBinaryTreeIsValidBST.java      |  4 +-
 .../trees/CheckIfBinaryTreeBalanced.java      |  4 +-
 .../trees/CheckTreeIsSymmetric.java           |  4 +-
 .../CreateBinaryTreeFromInorderPreorder.java  |  4 +-
 .../trees/InorderTraversal.java               |  4 +-
 .../datastructures/trees/LCA.java             |  4 +-
 .../trees/LevelOrderTraversal.java            |  4 +-
 .../trees/PostOrderTraversal.java             |  4 +-
 .../trees/PreOrderTraversal.java              |  4 +-
 .../trees/PrintTopViewofTree.java             |  4 +-
 .../datastructures/trees/SameTreesCheck.java  |  4 +-
 .../trees/VerticalOrderTraversal.java         |  4 +-
 .../datastructures/trees/ZigzagTraversal.java |  4 +-
 .../datastructures/trees/nearestRightKey.java |  4 +-
 .../dynamicprogramming/BoardPath.java         |  4 +-
 .../dynamicprogramming/BoundaryFill.java      |  4 +-
 .../BruteForceKnapsack.java                   |  4 +-
 .../dynamicprogramming/CatalanNumber.java     |  4 +-
 .../dynamicprogramming/ClimbingStairs.java    |  4 +-
 .../dynamicprogramming/CoinChange.java        |  4 +-
 .../CountFriendsPairing.java                  |  4 +-
 .../dynamicprogramming/DiceThrow.java         |  4 +-
 .../dynamicprogramming/EditDistance.java      |  4 +-
 .../dynamicprogramming/EggDropping.java       |  4 +-
 .../dynamicprogramming/Fibonacci.java         |  4 +-
 .../dynamicprogramming/FordFulkerson.java     |  4 +-
 .../dynamicprogramming/KadaneAlgorithm.java   |  4 +-
 .../LongestAlternatingSubsequence.java        |  4 +-
 .../LongestCommonSubsequence.java             |  4 +-
 .../LongestIncreasingSubsequence.java         |  4 +-
 .../LongestPalindromicSubsequence.java        |  4 +-
 .../LongestPalindromicSubstring.java          |  4 +-
 .../LongestValidParentheses.java              |  4 +-
 .../MatrixChainMultiplication.java            |  4 +-
 ...atrixChainRecursiveTopDownMemoisation.java |  4 +-
 .../dynamicprogramming/NewManShanksPrime.java |  4 +-
 .../PalindromicPartitioning.java              |  4 +-
 .../dynamicprogramming/PartitionProblem.java  |  4 +-
 .../dynamicprogramming/RegexMatching.java     |  4 +-
 .../dynamicprogramming/RodCutting.java        |  4 +-
 .../ShortestCommonSupersequenceLength.java    |  4 +-
 .../dynamicprogramming/SubsetSum.java         |  4 +-
 .../dynamicprogramming/SumOfSubset.java       |  4 +-
 .../dynamicprogramming/Tribonacci.java        |  4 +-
 .../dynamicprogramming/WildcardMatching.java  |  4 +-
 .../dynamicprogramming/WineProblem.java       |  4 +-
 .../greedyalgorithms/ActivitySelection.java   |  4 +-
 .../greedyalgorithms/CoinChange.java          |  4 +-
 .../greedyalgorithms/FractionalKnapsack.java  |  4 +-
 .../greedyalgorithms/JobSequencing.java       |  4 +-
 .../greedyalgorithms/MinimizingLateness.java  |  4 +-
 .../com/thealgorithms/maths/AbsoluteMax.java  |  4 +-
 .../com/thealgorithms/maths/AbsoluteMin.java  |  4 +-
 .../thealgorithms/maths/AbsoluteValue.java    |  4 +-
 .../com/thealgorithms/maths/AliquotSum.java   |  4 +-
 .../thealgorithms/maths/AmicableNumber.java   |  4 +-
 .../java/com/thealgorithms/maths/Area.java    |  4 +-
 .../thealgorithms/maths/AutoCorrelation.java  |  4 +-
 .../maths/AutomorphicNumber.java              |  4 +-
 .../java/com/thealgorithms/maths/Average.java |  4 +-
 .../com/thealgorithms/maths/BinaryPow.java    |  4 +-
 .../maths/BinomialCoefficient.java            |  4 +-
 .../java/com/thealgorithms/maths/Ceil.java    |  4 +-
 .../maths/CircularConvolutionFFT.java         |  4 +-
 .../com/thealgorithms/maths/Combinations.java |  4 +-
 .../com/thealgorithms/maths/Convolution.java  |  4 +-
 .../thealgorithms/maths/ConvolutionFFT.java   |  4 +-
 .../thealgorithms/maths/CrossCorrelation.java |  4 +-
 .../maths/DeterminantOfMatrix.java            |  4 +-
 .../com/thealgorithms/maths/DigitalRoot.java  |  4 +-
 .../thealgorithms/maths/DistanceFormula.java  |  4 +-
 .../thealgorithms/maths/DudeneyNumber.java    |  4 +-
 .../com/thealgorithms/maths/EulerMethod.java  |  4 +-
 .../java/com/thealgorithms/maths/FFT.java     |  4 +-
 .../com/thealgorithms/maths/FFTBluestein.java |  4 +-
 .../thealgorithms/maths/FastInverseSqrt.java  |  4 +-
 .../maths/FibonacciJavaStreams.java           |  4 +-
 .../maths/FibonacciNumberCheck.java           |  4 +-
 .../thealgorithms/maths/FindKthNumber.java    |  4 +-
 .../com/thealgorithms/maths/FrizzyNumber.java |  4 +-
 .../java/com/thealgorithms/maths/GCD.java     |  4 +-
 .../com/thealgorithms/maths/GCDRecursion.java |  4 +-
 .../com/thealgorithms/maths/Gaussian.java     |  4 +-
 .../thealgorithms/maths/HarshadNumber.java    |  4 +-
 .../thealgorithms/maths/JosephusProblem.java  |  4 +-
 .../thealgorithms/maths/JugglerSequence.java  |  4 +-
 .../thealgorithms/maths/KaprekarNumbers.java  |  4 +-
 .../com/thealgorithms/maths/KeithNumber.java  |  4 +-
 .../maths/KrishnamurthyNumber.java            |  4 +-
 .../maths/LeastCommonMultiple.java            |  4 +-
 .../thealgorithms/maths/LeonardoNumber.java   |  4 +-
 .../LinearDiophantineEquationsSolver.java     |  2 +
 .../maths/LiouvilleLambdaFunction.java        |  4 +-
 .../com/thealgorithms/maths/LongDivision.java |  4 +-
 .../com/thealgorithms/maths/LucasSeries.java  |  4 +-
 .../com/thealgorithms/maths/MagicSquare.java  |  4 +-
 .../com/thealgorithms/maths/MatrixUtil.java   |  4 +-
 .../java/com/thealgorithms/maths/Median.java  |  4 +-
 .../maths/MillerRabinPrimalityCheck.java      |  4 +-
 .../thealgorithms/maths/MobiusFunction.java   |  4 +-
 .../maths/NonRepeatingElement.java            |  4 +-
 .../thealgorithms/maths/PalindromeNumber.java |  4 +-
 .../thealgorithms/maths/PascalTriangle.java   |  4 +-
 .../com/thealgorithms/maths/PerfectCube.java  |  4 +-
 .../thealgorithms/maths/PerfectNumber.java    |  4 +-
 .../com/thealgorithms/maths/Perimeter.java    |  4 +-
 .../com/thealgorithms/maths/PiNilakantha.java |  4 +-
 .../com/thealgorithms/maths/PollardRho.java   |  4 +-
 .../java/com/thealgorithms/maths/Pow.java     |  4 +-
 .../maths/PowerUsingRecursion.java            |  4 +-
 .../com/thealgorithms/maths/PrimeCheck.java   |  4 +-
 .../maths/PrimeFactorization.java             |  4 +-
 .../com/thealgorithms/maths/PronicNumber.java |  4 +-
 .../maths/PythagoreanTriple.java              |  4 +-
 .../thealgorithms/maths/RomanNumeralUtil.java |  4 +-
 .../maths/SquareFreeInteger.java              |  4 +-
 .../maths/SquareRootWithBabylonianMethod.java |  4 +-
 .../SquareRootWithNewtonRaphsonMethod.java    |  4 +-
 .../maths/StandardDeviation.java              |  4 +-
 .../thealgorithms/maths/StandardScore.java    |  4 +-
 .../maths/TrinomialTriangle.java              |  4 +-
 .../com/thealgorithms/maths/TwinPrime.java    |  4 +-
 .../thealgorithms/maths/VampireNumber.java    |  4 +-
 .../java/com/thealgorithms/maths/Volume.java  |  4 +-
 .../matrixexponentiation/Fibonacci.java       |  4 +-
 .../thealgorithms/misc/InverseOfMatrix.java   |  4 +-
 .../com/thealgorithms/misc/MapReduce.java     |  4 +-
 .../thealgorithms/misc/MedianOfMatrix.java    |  2 +
 .../thealgorithms/misc/PalindromePrime.java   |  4 +-
 .../misc/RangeInSortedArray.java              |  4 +-
 .../java/com/thealgorithms/misc/Sort012D.java |  4 +-
 .../misc/{Sparcity.java => Sparsity.java}     | 14 +--
 .../com/thealgorithms/misc/WordBoggle.java    |  4 +-
 .../thealgorithms/misc/matrixTranspose.java   |  4 +-
 .../others/ArrayLeftRotation.java             |  4 +-
 .../java/com/thealgorithms/others/BFPRT.java  |  4 +-
 .../others/BankersAlgorithm.java              |  4 +-
 .../others/BrianKernighanAlgorithm.java       |  4 +-
 .../java/com/thealgorithms/others/CRC16.java  |  4 +-
 .../java/com/thealgorithms/others/CRC32.java  |  4 +-
 .../java/com/thealgorithms/others/Conway.java |  4 +-
 .../com/thealgorithms/others/CountChar.java   |  4 +-
 .../java/com/thealgorithms/others/Damm.java   |  4 +-
 .../com/thealgorithms/others/Dijkstra.java    |  4 +-
 .../thealgorithms/others/FibbonaciSeries.java |  4 +-
 .../thealgorithms/others/FloydTriangle.java   |  4 +-
 .../thealgorithms/others/GuassLegendre.java   |  4 +-
 .../thealgorithms/others/HappyNumbersSeq.java |  4 +-
 .../com/thealgorithms/others/Huffman.java     |  4 +-
 .../others/InsertDeleteInArray.java           |  4 +-
 .../java/com/thealgorithms/others/KMP.java    |  4 +-
 .../thealgorithms/others/KochSnowflake.java   |  4 +-
 .../thealgorithms/others/Krishnamurthy.java   |  4 +-
 .../com/thealgorithms/others/LineSweep.java   |  4 +-
 .../java/com/thealgorithms/others/Luhn.java   |  4 +-
 .../com/thealgorithms/others/Mandelbrot.java  |  4 +-
 ...imumSumOfDistinctSubarraysWithLengthK.java |  4 +-
 .../com/thealgorithms/others/PasswordGen.java |  7 +-
 .../com/thealgorithms/others/PerlinNoise.java |  4 +-
 .../others/QueueUsingTwoStacks.java           |  4 +-
 .../com/thealgorithms/others/RabinKarp.java   |  4 +-
 .../others/RemoveDuplicateFromString.java     |  4 +-
 .../others/ReturnSubsequence.java             |  4 +-
 .../others/ReverseStackUsingRecursion.java    |  4 +-
 .../thealgorithms/others/RootPrecision.java   |  4 +-
 ...gree.java => RotateMatrixBy90Degrees.java} |  8 +-
 .../others/StringMatchFiniteAutomata.java     |  4 +-
 .../java/com/thealgorithms/others/Sudoku.java |  4 +-
 .../com/thealgorithms/others/TopKWords.java   |  4 +-
 .../thealgorithms/others/TowerOfHanoi.java    |  4 +-
 .../com/thealgorithms/others/TwoPointers.java |  4 +-
 .../com/thealgorithms/others/Verhoeff.java    |  4 +-
 .../PreemptivePriorityScheduling.java         |  4 +-
 .../searches/BinarySearch2dArray.java         |  4 +-
 .../searches/HowManyTimesRotated.java         |  4 +-
 .../searches/LinearSearchThread.java          |  4 +-
 .../searches/OrderAgnosticBinarySearch.java   | 94 ++++++++++---------
 .../thealgorithms/searches/QuickSelect.java   |  2 +
 .../searches/SaddlebackSearch.java            |  4 +-
 .../searches/SquareRootBinarySearch.java      |  4 +-
 .../sortOrderAgnosticBinarySearch.java        |  4 +-
 .../com/thealgorithms/sorts/BucketSort.java   |  4 +-
 .../java/com/thealgorithms/sorts/DNFSort.java |  4 +-
 .../sorts/MergeSortNoExtraSpace.java          |  4 +-
 .../com/thealgorithms/sorts/OddEvenSort.java  |  4 +-
 .../com/thealgorithms/sorts/RadixSort.java    |  4 +-
 .../com/thealgorithms/sorts/SortUtils.java    |  2 +
 .../sorts/SortUtilsRandomGenerator.java       |  4 +-
 .../com/thealgorithms/sorts/StrandSort.java   |  4 +-
 .../thealgorithms/sorts/TopologicalSort.java  |  4 +-
 .../stacks/BalancedBrackets.java              |  4 +-
 .../stacks/DecimalToAnyUsingStack.java        |  4 +-
 .../stacks/DuplicateBrackets.java             |  4 +-
 .../thealgorithms/stacks/InfixToPostfix.java  |  4 +-
 .../stacks/LargestRectangle.java              |  4 +-
 .../stacks/MaximumMinimumWindow.java          |  4 +-
 .../stacks/NextGreaterElement.java            |  4 +-
 .../stacks/NextSmallerElement.java            |  4 +-
 .../thealgorithms/stacks/PostfixToInfix.java  |  4 +-
 .../thealgorithms/strings/Alphabetical.java   |  4 +-
 .../thealgorithms/strings/CharactersSame.java |  4 +-
 .../thealgorithms/strings/CheckAnagrams.java  |  4 +-
 .../thealgorithms/strings/CheckVowels.java    |  4 +-
 .../strings/HammingDistance.java              |  4 +-
 .../thealgorithms/strings/HorspoolSearch.java |  4 +-
 .../com/thealgorithms/strings/Isomorphic.java |  4 +-
 .../LetterCombinationsOfPhoneNumber.java      |  4 +-
 .../strings/LongestPalindromicSubstring.java  |  4 +-
 .../java/com/thealgorithms/strings/Lower.java |  4 +-
 .../com/thealgorithms/strings/MyAtoi.java     |  4 +-
 .../com/thealgorithms/strings/Palindrome.java |  4 +-
 .../com/thealgorithms/strings/Pangram.java    |  4 +-
 .../thealgorithms/strings/PermuteString.java  |  4 +-
 .../thealgorithms/strings/ReverseString.java  |  4 +-
 .../strings/ReverseStringRecursive.java       |  4 +-
 .../com/thealgorithms/strings/Rotation.java   |  4 +-
 .../strings/StringCompression.java            |  4 +-
 .../java/com/thealgorithms/strings/Upper.java |  4 +-
 .../strings/ValidParentheses.java             |  4 +-
 .../com/thealgorithms/strings/WordLadder.java |  4 +-
 .../strings/longestNonRepeativeSubstring.java |  4 +-
 .../strings/zigZagPattern/zigZagPattern.java  |  4 +-
 .../datastructures/trees/TreeTestUtils.java   |  4 +-
 .../others/ArrayRightRotation.java            |  4 +-
 .../com/thealgorithms/others/CRC16Test.java   |  3 -
 .../thealgorithms/strings/IsomorphicTest.java |  4 +-
 .../strings/ReverseStringRecursiveTest.java   |  2 -
 285 files changed, 895 insertions(+), 339 deletions(-)
 rename src/main/java/com/thealgorithms/misc/{Sparcity.java => Sparsity.java} (82%)
 rename src/main/java/com/thealgorithms/others/{RotateMatriceBy90Degree.java => RotateMatrixBy90Degrees.java} (92%)

diff --git a/checkstyle.xml b/checkstyle.xml
index 8424e07f2694..5bbc5d72229a 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -175,7 +175,7 @@
     <!-- See https://checkstyle.org/checks/design/index.html -->
     <!-- TODO <module name="DesignForExtension"/> -->
     <!-- TODO <module name="FinalClass"/> -->
-    <!-- TODO <module name="HideUtilityClassConstructor"/> -->
+    <module name="HideUtilityClassConstructor"/>
     <module name="InterfaceIsType"/>
     <!-- TODO <module name="VisibilityModifier"/> -->
 
diff --git a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
index a25bf51de898..a0b886e6be8a 100644
--- a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
+++ b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
@@ -7,7 +7,9 @@
  * Finds all permutations of 1...n of length k
  * @author TheClerici (<a href="https://github.com/TheClerici">git-TheClerici</a>)
  */
-public class ArrayCombination {
+public final class ArrayCombination {
+    private ArrayCombination() {
+    }
     private static int length;
 
     /**
diff --git a/src/main/java/com/thealgorithms/backtracking/Combination.java b/src/main/java/com/thealgorithms/backtracking/Combination.java
index 3908da43b36a..80c11ce737fa 100644
--- a/src/main/java/com/thealgorithms/backtracking/Combination.java
+++ b/src/main/java/com/thealgorithms/backtracking/Combination.java
@@ -9,7 +9,9 @@
  * Finds all permutations of given array
  * @author Alan Piao (<a href="https://github.com/cpiao3">git-Alan Piao</a>)
  */
-public class Combination {
+public final class Combination {
+    private Combination() {
+    }
 
     private static int length;
 
diff --git a/src/main/java/com/thealgorithms/backtracking/KnightsTour.java b/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
index 694f4ad18b08..2287b39da385 100644
--- a/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
+++ b/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
@@ -26,7 +26,9 @@
         51  46  55  44  53   4  21  12
 
  */
-public class KnightsTour {
+public final class KnightsTour {
+    private KnightsTour() {
+    }
 
     private static final int BASE = 12;
     private static final int[][] MOVES = {
diff --git a/src/main/java/com/thealgorithms/backtracking/MColoring.java b/src/main/java/com/thealgorithms/backtracking/MColoring.java
index d7d0a1d2f36b..20c42e59e8a1 100644
--- a/src/main/java/com/thealgorithms/backtracking/MColoring.java
+++ b/src/main/java/com/thealgorithms/backtracking/MColoring.java
@@ -14,7 +14,9 @@ class Node {
     Set<Integer> edges = new HashSet<Integer>();
 }
 
-public class MColoring {
+public final class MColoring {
+    private MColoring() {
+    }
     static int possiblePaint(ArrayList<Node> nodes, int n, int m) {
 
         // Create a visited array of n nodes
diff --git a/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java b/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java
index 23fc0689fd57..f7eae01e449a 100644
--- a/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java
+++ b/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.backtracking;
 
-public class MazeRecursion {
+public final class MazeRecursion {
+    private MazeRecursion() {
+    }
 
     public static void mazeRecursion() {
         // First create a 2 dimensions array to mimic a maze map
diff --git a/src/main/java/com/thealgorithms/backtracking/NQueens.java b/src/main/java/com/thealgorithms/backtracking/NQueens.java
index e40b82915cc9..e21a8bb7174c 100644
--- a/src/main/java/com/thealgorithms/backtracking/NQueens.java
+++ b/src/main/java/com/thealgorithms/backtracking/NQueens.java
@@ -32,7 +32,9 @@
  * queen is not placed safely. If there is no such way then return an empty list
  * as solution
  */
-public class NQueens {
+public final class NQueens {
+    private NQueens() {
+    }
 
     public static void main(String[] args) {
         placeQueens(1);
diff --git a/src/main/java/com/thealgorithms/backtracking/Permutation.java b/src/main/java/com/thealgorithms/backtracking/Permutation.java
index 5d88c846087e..21d26e53980f 100644
--- a/src/main/java/com/thealgorithms/backtracking/Permutation.java
+++ b/src/main/java/com/thealgorithms/backtracking/Permutation.java
@@ -7,7 +7,9 @@
  * Finds all permutations of given array
  * @author Alan Piao (<a href="https://github.com/cpiao3">Git-Alan Piao</a>)
  */
-public class Permutation {
+public final class Permutation {
+    private Permutation() {
+    }
 
     /**
      * Find all permutations of given array using backtracking
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java b/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java
index dc8a217875f9..b825916a8674 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java
@@ -5,7 +5,9 @@
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
 
-public class IndexOfRightMostSetBit {
+public final class IndexOfRightMostSetBit {
+    private IndexOfRightMostSetBit() {
+    }
     public static int indexOfRightMostSetBit(int n) {
         if (n == 0) {
             return -1; // No set bits
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java b/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java
index b6bdc25fcc2b..09d5383322ff 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java
@@ -5,7 +5,9 @@
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
 
-public class IsEven {
+public final class IsEven {
+    private IsEven() {
+    }
     public static boolean isEven(int number) {
         return (number & 1) == 0;
     }
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java b/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java
index d379cb3f0593..54d28d4d22cc 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java
@@ -5,7 +5,9 @@
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
 
-public class IsPowerTwo {
+public final class IsPowerTwo {
+    private IsPowerTwo() {
+    }
     public static boolean isPowerTwo(int number) {
         if (number <= 0) {
             return false;
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java b/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java
index bd4bdb0becae..07476a8b9476 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java
@@ -5,7 +5,9 @@
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
 
-public class NonRepeatingNumberFinder {
+public final class NonRepeatingNumberFinder {
+    private NonRepeatingNumberFinder() {
+    }
 
     public static int findNonRepeatingNumber(int[] arr) {
         int result = 0;
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java b/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java
index ed586296776f..8e0946f0eb23 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java
@@ -5,7 +5,9 @@
  * @author Bama Charan Chhandogi
  */
 
-public class NumbersDifferentSigns {
+public final class NumbersDifferentSigns {
+    private NumbersDifferentSigns() {
+    }
 
     public static boolean differentSigns(int num1, int num2) {
         return (num1 ^ num2) < 0;
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java b/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java
index e9d1ad61996f..e8f2930d3afe 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java
@@ -5,7 +5,9 @@
  * @author Bama Charan Chhandogi
  */
 
-public class ReverseBits {
+public final class ReverseBits {
+    private ReverseBits() {
+    }
 
     public static int reverseBits(int n) {
         int result = 0;
diff --git a/src/main/java/com/thealgorithms/ciphers/AES.java b/src/main/java/com/thealgorithms/ciphers/AES.java
index e310d7189b2a..cd04395e1b72 100644
--- a/src/main/java/com/thealgorithms/ciphers/AES.java
+++ b/src/main/java/com/thealgorithms/ciphers/AES.java
@@ -7,7 +7,9 @@
  * This class is build to demonstrate the application of the AES-algorithm on a
  * single 128-Bit block of data.
  */
-public class AES {
+public final class AES {
+    private AES() {
+    }
 
     /**
      * Precalculated values for x to the power of 2 in Rijndaels galois field.
diff --git a/src/main/java/com/thealgorithms/ciphers/AESEncryption.java b/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
index 92c1f6f5a4fd..14582205442f 100644
--- a/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
+++ b/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
@@ -17,7 +17,9 @@
  * hence in the following program we display it in hexadecimal format of the
  * underlying bytes.
  */
-public class AESEncryption {
+public final class AESEncryption {
+    private AESEncryption() {
+    }
 
     private static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();
     private static Cipher aesCipher;
diff --git a/src/main/java/com/thealgorithms/ciphers/AffineCipher.java b/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
index 9ff63ddfe7c5..6e819f56041c 100644
--- a/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.ciphers;
 
-class AffineCipher {
+final class AffineCipher {
+    private AffineCipher() {
+    }
 
     // Key values of a and b
     static int a = 17;
diff --git a/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java b/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java
index 89a0a88654ae..e59cfb12d816 100644
--- a/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java
@@ -7,7 +7,9 @@
  *
  * @author <a href="https://github.com/freitzzz">freitzzz</a>
  */
-public class ColumnarTranspositionCipher {
+public final class ColumnarTranspositionCipher {
+    private ColumnarTranspositionCipher() {
+    }
 
     private static String keyword;
     private static Object[][] table;
diff --git a/src/main/java/com/thealgorithms/ciphers/HillCipher.java b/src/main/java/com/thealgorithms/ciphers/HillCipher.java
index a3226cef7de1..a858eb402939 100644
--- a/src/main/java/com/thealgorithms/ciphers/HillCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/HillCipher.java
@@ -11,7 +11,9 @@
  * for encryption. The cipher key and plaintext/ciphertext are user inputs.
  * @author Ojasva Jain
  */
-public class HillCipher {
+public final class HillCipher {
+    private HillCipher() {
+    }
 
     static Scanner userInput = new Scanner(System.in);
 
diff --git a/src/main/java/com/thealgorithms/ciphers/Polybius.java b/src/main/java/com/thealgorithms/ciphers/Polybius.java
index b28cac8a586e..6b3cd6ccae81 100644
--- a/src/main/java/com/thealgorithms/ciphers/Polybius.java
+++ b/src/main/java/com/thealgorithms/ciphers/Polybius.java
@@ -13,7 +13,9 @@
  * @author Hikmet ÇAKIR
  * @since 08-07-2022+03:00
  */
-public class Polybius {
+public final class Polybius {
+    private Polybius() {
+    }
 
     private static final char[][] KEY = {
         //         0    1    2    3    4
diff --git a/src/main/java/com/thealgorithms/ciphers/ProductCipher.java b/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
index 5b1d46fe9a9a..fb49d6cd61db 100644
--- a/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-class ProductCipher {
+final class ProductCipher {
+    private ProductCipher() {
+    }
 
     public static void main(String[] args) {
         try (Scanner sc = new Scanner(System.in)) {
diff --git a/src/main/java/com/thealgorithms/ciphers/a5/Utils.java b/src/main/java/com/thealgorithms/ciphers/a5/Utils.java
index abdd11d6b72d..b4addf18dd9d 100644
--- a/src/main/java/com/thealgorithms/ciphers/a5/Utils.java
+++ b/src/main/java/com/thealgorithms/ciphers/a5/Utils.java
@@ -7,7 +7,9 @@
 
 import java.util.BitSet;
 
-public class Utils {
+public final class Utils {
+    private Utils() {
+    }
 
     public static boolean increment(BitSet bits, int size) {
         int i = size - 1;
diff --git a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
index 7a87fd15be23..a5fc72c8bfb4 100644
--- a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
+++ b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
@@ -13,7 +13,9 @@
  * @author Michael Rolland
  * @version 2017.10.10
  */
-public class AnyBaseToAnyBase {
+public final class AnyBaseToAnyBase {
+    private AnyBaseToAnyBase() {
+    }
 
     /**
      * Smallest and largest base you want to accept as valid input
diff --git a/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java b/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java
index 20f15bc2ff39..6b4b14adc955 100644
--- a/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java
@@ -4,7 +4,9 @@
  * @author Varun Upadhyay (<a href="https://github.com/varunu28">...</a>)
  */
 // Driver program
-public class AnyBaseToDecimal {
+public final class AnyBaseToDecimal {
+    private AnyBaseToDecimal() {
+    }
 
     public static void main(String[] args) {
         assert convertToDecimal("1010", 2) == Integer.valueOf("1010", 2);
diff --git a/src/main/java/com/thealgorithms/conversions/AnytoAny.java b/src/main/java/com/thealgorithms/conversions/AnytoAny.java
index 052d6dba6953..609a81561b1b 100644
--- a/src/main/java/com/thealgorithms/conversions/AnytoAny.java
+++ b/src/main/java/com/thealgorithms/conversions/AnytoAny.java
@@ -6,7 +6,9 @@
 // number.
 // sn ,sb,db ---> ()dn  .   this is what we have to do    .
 
-public class AnytoAny {
+public final class AnytoAny {
+    private AnytoAny() {
+    }
 
     public static void main(String[] args) {
         Scanner scn = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java b/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
index fdf9df7b2467..57d49d7b17f8 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
@@ -5,7 +5,9 @@
 /**
  * This class converts a Binary number to a Decimal number
  */
-class BinaryToDecimal {
+final class BinaryToDecimal {
+    private BinaryToDecimal() {
+    }
 
     public static long binaryToDecimal(long binNum) {
         long binCopy, d, s = 0, power = 0;
diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java b/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
index 9980d6deb8fc..a19baba39715 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
@@ -8,7 +8,9 @@
  *
  * @author Nishita Aggarwal
  */
-public class BinaryToHexadecimal {
+public final class BinaryToHexadecimal {
+    private BinaryToHexadecimal() {
+    }
 
     /**
      * This method converts a binary number to a hexadecimal number.
diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java b/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java
index 70bad812141b..f171cdf69801 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java
@@ -7,7 +7,9 @@
  *
  * @author Zachary Jones
  */
-public class BinaryToOctal {
+public final class BinaryToOctal {
+    private BinaryToOctal() {
+    }
 
     /**
      * Main method
diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java b/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java
index 2d0223a4c448..019c4026bfb5 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java
@@ -8,7 +8,9 @@
  * @author Varun Upadhyay (<a href="https://github.com/varunu28">...</a>)
  */
 // Driver Program
-public class DecimalToAnyBase {
+public final class DecimalToAnyBase {
+    private DecimalToAnyBase() {
+    }
 
     public static void main(String[] args) throws Exception {
         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java b/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java
index a6119cfbc9bc..329985a05fde 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java
@@ -5,7 +5,9 @@
 /**
  * This class converts a Decimal number to a Binary number
  */
-class DecimalToBinary {
+final class DecimalToBinary {
+    private DecimalToBinary() {
+    }
 
     /**
      * Main Method
diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java b/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java
index 1435c7f8b5fa..78838c6107b7 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java
@@ -1,7 +1,9 @@
 package com.thealgorithms.conversions;
 
 // hex = [0 - 9] -> [A - F]
-class DecimalToHexaDecimal {
+final class DecimalToHexaDecimal {
+    private DecimalToHexaDecimal() {
+    }
 
     private static final int SIZE_OF_INT_IN_HALF_BYTES = 8;
     private static final int NUMBER_OF_BITS_IN_HALF_BYTE = 4;
diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java b/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java
index 0f72f462c753..1d0a6f1a1060 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java
@@ -5,7 +5,9 @@
 /**
  * This class converts Decimal numbers to Octal Numbers
  */
-public class DecimalToOctal {
+public final class DecimalToOctal {
+    private DecimalToOctal() {
+    }
 
     /**
      * Main Method
diff --git a/src/main/java/com/thealgorithms/conversions/HexToOct.java b/src/main/java/com/thealgorithms/conversions/HexToOct.java
index 2a57fbde5c41..b4994ae0f5fb 100644
--- a/src/main/java/com/thealgorithms/conversions/HexToOct.java
+++ b/src/main/java/com/thealgorithms/conversions/HexToOct.java
@@ -7,7 +7,9 @@
  *
  * @author Tanmay Joshi
  */
-public class HexToOct {
+public final class HexToOct {
+    private HexToOct() {
+    }
 
     /**
      * This method converts a Hexadecimal number to a decimal number
diff --git a/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java b/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java
index 7675c83ebcfa..e8a44cb827d5 100644
--- a/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-public class HexaDecimalToDecimal {
+public final class HexaDecimalToDecimal {
+    private HexaDecimalToDecimal() {
+    }
 
     // convert hexadecimal to decimal
     public static int getHexaToDec(String hex) {
diff --git a/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java b/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
index 5507ab1169af..9c031df9504d 100644
--- a/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
+++ b/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
@@ -7,7 +7,9 @@
  * ('I', 1); ('IV',4); ('V', 5); ('IX',9); ('X', 10); ('XL',40); ('L', 50);
  * ('XC',90); ('C', 100); ('D', 500); ('M', 1000);
  */
-public class IntegerToRoman {
+public final class IntegerToRoman {
+    private IntegerToRoman() {
+    }
 
     private static final int[] ALL_ROMAN_NUMBERS_IN_ARABIC = new int[] {
         1000,
diff --git a/src/main/java/com/thealgorithms/conversions/OctalToBinary.java b/src/main/java/com/thealgorithms/conversions/OctalToBinary.java
index 4dd581bd6116..6b01c2f65cfe 100644
--- a/src/main/java/com/thealgorithms/conversions/OctalToBinary.java
+++ b/src/main/java/com/thealgorithms/conversions/OctalToBinary.java
@@ -6,7 +6,9 @@
  * @author Bama Charan Chhandogi
  */
 
-public class OctalToBinary {
+public final class OctalToBinary {
+    private OctalToBinary() {
+    }
     public static long convertOctalToBinary(int octalNumber) {
         long binaryNumber = 0;
         int digitPosition = 1;
diff --git a/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java b/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java
index d4916a3dbcca..187f0ed1e2ea 100644
--- a/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java
@@ -7,7 +7,9 @@
  *
  * @author Zachary Jones
  */
-public class OctalToDecimal {
+public final class OctalToDecimal {
+    private OctalToDecimal() {
+    }
 
     /**
      * Main method
diff --git a/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java b/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java
index 5edd94c38430..5cc97fde12aa 100644
--- a/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java
@@ -7,7 +7,9 @@
  *
  * @author Tanmay Joshi
  */
-public class OctalToHexadecimal {
+public final class OctalToHexadecimal {
+    private OctalToHexadecimal() {
+    }
 
     /**
      * This method converts a Octal number to a decimal number
diff --git a/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java b/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java
index 65cb00fc0ad0..84cbff09db6b 100644
--- a/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java
+++ b/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java
@@ -13,7 +13,9 @@
  * (description adapted from <a href="https://en.wikipedia.org/wiki/RGB_color_model">[1]</a> and
  * <a href="https://en.wikipedia.org/wiki/HSL_and_HSV">[2]</a>).
  */
-public class RgbHsvConversion {
+public final class RgbHsvConversion {
+    private RgbHsvConversion() {
+    }
 
     public static void main(String[] args) {
         // Expected RGB-values taken from https://www.rapidtables.com/convert/color/hsv-to-rgb.html
diff --git a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
index 1338ba9bb8ef..6ffb41c3c0e2 100644
--- a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
+++ b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
@@ -3,7 +3,9 @@
 import java.util.HashMap;
 import java.util.Map;
 
-public class RomanToInteger {
+public final class RomanToInteger {
+    private RomanToInteger() {
+    }
 
     private static final Map<Character, Integer> ROMAN_TO_INT = new HashMap<>() {
         {
diff --git a/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java b/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
index a96791b7706b..4d13b8b7fd55 100644
--- a/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
+++ b/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
@@ -7,7 +7,9 @@
  *
  * @author Özgün Gökşenli
  */
-public class TurkishToLatinConversion {
+public final class TurkishToLatinConversion {
+    private TurkishToLatinConversion() {
+    }
 
     /**
      * Main method
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java b/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
index 0da876148e43..b1af21eb6ff2 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
@@ -9,7 +9,9 @@
 import java.util.List;
 import java.util.PriorityQueue;
 
-public class A_Star {
+public final class A_Star {
+    private A_Star() {
+    }
 
     private static class Graph {
 
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java b/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
index a4827d8881b3..6b41b658d5e2 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
@@ -14,7 +14,9 @@
  *
  * Output : YES
  */
-public class BipartiteGrapfDFS {
+public final class BipartiteGrapfDFS {
+    private BipartiteGrapfDFS() {
+    }
 
     private static boolean bipartite(int V, ArrayList<ArrayList<Integer>> adj, int[] color, int node) {
         if (color[node] == -1) {
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java b/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
index 9b6ff9010445..dadab2e5063c 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
@@ -107,7 +107,9 @@ public ArrayList<Node> depthFirstSearch(Node n, ArrayList<Node> visited) {
     }
 }
 
-public class ConnectedComponent {
+public final class ConnectedComponent {
+    private ConnectedComponent() {
+    }
 
     public static void main(String[] args) {
         Graph<Character> graphChars = new Graph<>();
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java b/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
index 7995e0146190..06debf3dcb7f 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
@@ -78,7 +78,9 @@ public void printAll() {
     }
 }
 
-public class Cycles {
+public final class Cycles {
+    private Cycles() {
+    }
 
     public static void main(String[] args) {
         Cycle c = new Cycle();
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java b/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java
index 01aa1085867b..3a13f6a698bd 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java
@@ -120,7 +120,9 @@ public String toString() {
     }
 }
 
-public class Graphs {
+public final class Graphs {
+    private Graphs() {
+    }
 
     public static void main(String[] args) {
         AdjacencyListGraph<Integer> graph = new AdjacencyListGraph<>();
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
index e978ddc1e764..145071890d76 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
@@ -130,7 +130,9 @@ ArrayList<E> topSortOrder() {
 /**
  * A driver class that sorts a given graph in topological order.
  */
-public class KahnsAlgorithm {
+public final class KahnsAlgorithm {
+    private KahnsAlgorithm() {
+    }
 
     public static void main(String[] args) {
         // Graph definition and initialization
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java b/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
index d595d53c1b61..c578053477d7 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
@@ -12,7 +12,9 @@
  *
  * @author Unknown
  */
-public class MatrixGraphs {
+public final class MatrixGraphs {
+    private MatrixGraphs() {
+    }
 
     public static void main(String[] args) {
         AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(10);
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
index d68e01284ddd..b4f0afc63729 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-public class Main {
+public final class Main {
+    private Main() {
+    }
 
     public static void main(String[] args) {
         int choice, key;
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
index 94d370b66976..f4e0f594de8f 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-public class MainCuckooHashing {
+public final class MainCuckooHashing {
+    private MainCuckooHashing() {
+    }
 
     public static void main(String[] args) {
         int choice, key;
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
index e3364b0e16fb..bfa5759a41b9 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
@@ -8,7 +8,9 @@ This class finds the majority element(s) in an array of integers.
 A majority element is an element that appears more than or equal to n/2 times, where n is the length
 of the array.
 */
-public class MajorityElement {
+public final class MajorityElement {
+    private MajorityElement() {
+    }
     /*
    This method returns the majority element(s) in the given array of integers.
    @param nums: an array of integers
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java b/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
index 182c8f75fe55..38133ad3491f 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-public class CreateAndDetectLoop {
+public final class CreateAndDetectLoop {
+    private CreateAndDetectLoop() {
+    }
 
     /**
      * Prints the linked list.
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java b/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java
index 80b36b8e4ab1..99ab09f81c1c 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java
@@ -6,7 +6,9 @@
 /**
  * @author https://github.com/shellhub
  */
-public class MergeSortedArrayList {
+public final class MergeSortedArrayList {
+    private MergeSortedArrayList() {
+    }
 
     public static void main(String[] args) {
         List<Integer> listA = new ArrayList<>();
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/Queues.java b/src/main/java/com/thealgorithms/datastructures/queues/Queues.java
index a8fabf7b8859..2f364b7cbb6b 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/Queues.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/Queues.java
@@ -152,7 +152,9 @@ public String toString() {
  *
  * @author Unknown
  */
-public class Queues {
+public final class Queues {
+    private Queues() {
+    }
 
     /**
      * Main method
diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java b/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
index c9d2ea05778b..0f9ef6f3a8e0 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
@@ -8,7 +8,9 @@
  *
  * @author Ishika Agarwal, 2021
  */
-public class ReverseStack {
+public final class ReverseStack {
+    private ReverseStack() {
+    }
 
     public static void main(String[] args) {
         try (Scanner sc = new Scanner(System.in)) {
diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java b/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java
index afe002fa3651..52b1c1d86c94 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java
@@ -6,7 +6,9 @@
  * @author Varun Upadhyay (https://github.com/varunu28)
  */
 // An implementation of a Stack using a Linked List
-class StackOfLinkedList {
+final class StackOfLinkedList {
+    private StackOfLinkedList() {
+    }
 
     public static void main(String[] args) {
         LinkedListStack stack = new LinkedListStack();
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/BSTFromSortedArray.java b/src/main/java/com/thealgorithms/datastructures/trees/BSTFromSortedArray.java
index 9066a6f231be..1962eaa0a106 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/BSTFromSortedArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/BSTFromSortedArray.java
@@ -9,7 +9,9 @@
  * left half recursively to create left subtree 3. Use the right half
  * recursively to create right subtree
  */
-public class BSTFromSortedArray {
+public final class BSTFromSortedArray {
+    private BSTFromSortedArray() {
+    }
     public static Node createBST(int[] array) {
         if (array == null || array.length == 0) {
             return null;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java b/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
index 6e1454f6859b..f238b5e9fe8d 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
@@ -42,7 +42,9 @@
  * subtree. If left subtree returns a non-null value then that will be ceil
  * otherwise the root is ceil
  */
-public class CeilInBinarySearchTree {
+public final class CeilInBinarySearchTree {
+    private CeilInBinarySearchTree() {
+    }
 
     public static Node getCeil(Node root, int key) {
         if (root == null) {
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBST.java b/src/main/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBST.java
index c034452f7221..0c2b44d78d74 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBST.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBST.java
@@ -8,7 +8,9 @@
  *    where 'min' and 'max' values represent the child nodes (left, right).
  * 2. The smallest possible node value is Integer.MIN_VALUE, the biggest - Integer.MAX_VALUE.
  */
-public class CheckBinaryTreeIsValidBST {
+public final class CheckBinaryTreeIsValidBST {
+    private CheckBinaryTreeIsValidBST() {
+    }
     public static boolean isBST(BinaryTree.Node root) {
         return isBSTUtil(root, Integer.MIN_VALUE, Integer.MAX_VALUE);
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalanced.java b/src/main/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalanced.java
index 566536256558..9aa4d5a1fef2 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalanced.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalanced.java
@@ -14,7 +14,9 @@
  *
  * @author [Ian Cowan](<a href="https://github.com/iccowan">Git-Ian Cowan</a>)
  */
-public class CheckIfBinaryTreeBalanced {
+public final class CheckIfBinaryTreeBalanced {
+    private CheckIfBinaryTreeBalanced() {
+    }
     /**
      * Recursive is BT balanced implementation
      *
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetric.java b/src/main/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetric.java
index def455dde051..17d84bf11d54 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetric.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetric.java
@@ -30,7 +30,9 @@
  *
  * @author kumanoit on 10/10/22 IST 12:52 AM
  */
-public class CheckTreeIsSymmetric {
+public final class CheckTreeIsSymmetric {
+    private CheckTreeIsSymmetric() {
+    }
 
     public static boolean isSymmetric(Node root) {
         if (root == null) {
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorder.java b/src/main/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorder.java
index 8303c658dfb8..04caa0b9e9d2 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorder.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorder.java
@@ -17,7 +17,9 @@
  * Complexity: Time: O(n) hashmap reduced iteration to find index in inorder
  * array Space: O(n) space taken by hashmap
  */
-public class CreateBinaryTreeFromInorderPreorder {
+public final class CreateBinaryTreeFromInorderPreorder {
+    private CreateBinaryTreeFromInorderPreorder() {
+    }
     public static Node createTree(final Integer[] preorder, final Integer[] inorder) {
         if (preorder == null || inorder == null) {
             return null;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java
index 6441375568ad..3bae17ed1bb8 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java
@@ -25,7 +25,9 @@
  *
  * @author Albina Gimaletdinova on 21/02/2023
  */
-public class InorderTraversal {
+public final class InorderTraversal {
+    private InorderTraversal() {
+    }
     public static List<Integer> recursiveInorder(BinaryTree.Node root) {
         List<Integer> result = new ArrayList<>();
         recursiveInorder(root, result);
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/LCA.java b/src/main/java/com/thealgorithms/datastructures/trees/LCA.java
index c8bac470d9b7..701077b0a549 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/LCA.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/LCA.java
@@ -3,7 +3,9 @@
 import java.util.ArrayList;
 import java.util.Scanner;
 
-public class LCA {
+public final class LCA {
+    private LCA() {
+    }
 
     private static final Scanner SCANNER = new Scanner(System.in);
 
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/LevelOrderTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/LevelOrderTraversal.java
index e61085cf4def..f91aa303f66c 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/LevelOrderTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/LevelOrderTraversal.java
@@ -5,7 +5,9 @@
 import java.util.List;
 import java.util.Queue;
 
-public class LevelOrderTraversal {
+public final class LevelOrderTraversal {
+    private LevelOrderTraversal() {
+    }
 
     public static List<List<Integer>> traverse(BinaryTree.Node root) {
         if (root == null) {
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java
index 3820345b95bf..50dc88381a24 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java
@@ -26,7 +26,9 @@
  *
  * @author Albina Gimaletdinova on 21/02/2023
  */
-public class PostOrderTraversal {
+public final class PostOrderTraversal {
+    private PostOrderTraversal() {
+    }
     public static List<Integer> recursivePostOrder(BinaryTree.Node root) {
         List<Integer> result = new ArrayList<>();
         recursivePostOrder(root, result);
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java
index d0a5bc4ac3f0..6a0eef369407 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java
@@ -25,7 +25,9 @@
  *
  * @author Albina Gimaletdinova on 17/02/2023
  */
-public class PreOrderTraversal {
+public final class PreOrderTraversal {
+    private PreOrderTraversal() {
+    }
     public static List<Integer> recursivePreOrder(BinaryTree.Node root) {
         List<Integer> result = new ArrayList<>();
         recursivePreOrder(root, result);
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java b/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
index 7560e90cd008..e30a52929519 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
@@ -87,7 +87,9 @@ public void printTopView() {
 }
 
 // Driver class to test above methods
-public class PrintTopViewofTree {
+public final class PrintTopViewofTree {
+    private PrintTopViewofTree() {
+    }
 
     public static void main(String[] args) {
         /* Create following Binary Tree
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java b/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java
index aede2a23b544..883eadd1840a 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java
@@ -32,7 +32,9 @@
  *
  * @author Albina Gimaletdinova on 13/01/2023
  */
-public class SameTreesCheck {
+public final class SameTreesCheck {
+    private SameTreesCheck() {
+    }
     public static boolean check(BinaryTree.Node p, BinaryTree.Node q) {
         if (p == null && q == null) {
             return true;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java
index a42b4370de68..63a75f6a2c9b 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java
@@ -20,7 +20,9 @@
  the sequence will be :
  4 2 7 1 5 9 3 8 6 10
  */
-public class VerticalOrderTraversal {
+public final class VerticalOrderTraversal {
+    private VerticalOrderTraversal() {
+    }
 
     /*Function that receives a root Node and prints the tree
         in Vertical Order.*/
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java
index 50158b0fae0a..84fe0eb2c42a 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java
@@ -34,7 +34,9 @@
  *
  * @author Albina Gimaletdinova on 11/01/2023
  */
-public class ZigzagTraversal {
+public final class ZigzagTraversal {
+    private ZigzagTraversal() {
+    }
     public static List<List<Integer>> traverse(BinaryTree.Node root) {
         if (root == null) {
             return List.of();
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java b/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java
index dd6df1481c99..797e5e4d56b8 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java
@@ -3,7 +3,9 @@
 import java.util.Scanner;
 import java.util.concurrent.ThreadLocalRandom;
 
-class Main {
+final class NearestRightKey {
+    private NearestRightKey() {
+    }
 
     public static void main(String[] args) {
         NRKTree root = BuildTree();
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java b/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java
index 7deb81448b55..b041cfc478d6 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java
@@ -25,7 +25,9 @@
 
 
  */
-public class BoardPath {
+public final class BoardPath {
+    private BoardPath() {
+    }
 
     public static long startTime;
     public static long endTime;
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java b/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
index 52d7bffa4980..7fa4e24383a8 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
@@ -4,7 +4,9 @@
  * Java program for Boundary fill algorithm.
  * @author Akshay Dubey (https://github.com/itsAkshayDubey)
  */
-public class BoundaryFill {
+public final class BoundaryFill {
+    private BoundaryFill() {
+    }
 
     /**
      * Get the color at the given co-odrinates of a 2D image
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java b/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
index 77d997fc2adc..5aba97eea1d8 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
@@ -2,7 +2,9 @@
 
 /* A Naive recursive implementation
 of 0-1 Knapsack problem */
-public class BruteForceKnapsack {
+public final class BruteForceKnapsack {
+    private BruteForceKnapsack() {
+    }
     // Returns the maximum value that
     // can be put in a knapsack of
     // capacity W
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java b/src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java
index 5db7d39f1d99..8658bca3df52 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java
@@ -10,7 +10,9 @@
  */
 import java.util.Scanner;
 
-public class CatalanNumber {
+public final class CatalanNumber {
+    private CatalanNumber() {
+    }
 
     /**
      * This method finds the nth Catalan number
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java b/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java
index 58ba1351109c..d79ed3c23e13 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java
@@ -5,7 +5,9 @@
 
     Link : https://medium.com/analytics-vidhya/leetcode-q70-climbing-stairs-easy-444a4aae54e8
 */
-public class ClimbingStairs {
+public final class ClimbingStairs {
+    private ClimbingStairs() {
+    }
 
     public static int numberOfWays(int n) {
 
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java b/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java
index b5be0b2660bf..bcd8b94a89ba 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java
@@ -3,7 +3,9 @@
 /**
  * @author Varun Upadhyay (https://github.com/varunu28)
  */
-public class CoinChange {
+public final class CoinChange {
+    private CoinChange() {
+    }
 
     // Driver Program
     public static void main(String[] args) {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java b/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java
index e18725405394..8c70c9c3fada 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java
@@ -15,7 +15,9 @@
 
 package com.thealgorithms.dynamicprogramming;
 
-public class CountFriendsPairing {
+public final class CountFriendsPairing {
+    private CountFriendsPairing() {
+    }
 
     public static boolean countFriendsPairing(int n, int[] a) {
         int[] dp = new int[n + 1];
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java b/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java
index 84f9cf6a83d8..e1be3ead5895 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java
@@ -13,7 +13,9 @@ And it can be done using Dynamic Programming(DP).
 // Code ---->
 // Java program to find number of ways to get sum 'x' with 'n'
 // dice where every dice has 'm' faces
-class DP {
+final class DP {
+    private DP() {
+    }
 
     /* The main function that returns the number of ways to get sum 'x' with 'n' dice and 'm' with m
      * faces. */
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java b/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
index 68877811092e..7a7b0f006b57 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
@@ -24,7 +24,9 @@
  */
 import java.util.Scanner;
 
-public class EditDistance {
+public final class EditDistance {
+    private EditDistance() {
+    }
 
     public static int minDistance(String word1, String word2) {
         int len1 = word1.length();
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java b/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java
index ef1ff49465f3..c50522421d47 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java
@@ -3,7 +3,9 @@
 /**
  * DynamicProgramming solution for the Egg Dropping Puzzle
  */
-public class EggDropping {
+public final class EggDropping {
+    private EggDropping() {
+    }
 
     // min trials with n eggs and m floors
     public static int minTrials(int n, int m) {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
index 81dd504ed791..2d768df55a7a 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
@@ -7,7 +7,9 @@
 /**
  * @author Varun Upadhyay (https://github.com/varunu28)
  */
-public class Fibonacci {
+public final class Fibonacci {
+    private Fibonacci() {
+    }
 
     private static final Map<Integer, Integer> CACHE = new HashMap<>();
 
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java b/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
index 63ec477c4590..9e1516ec3570 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
@@ -4,7 +4,9 @@
 import java.util.Queue;
 import java.util.Vector;
 
-public class FordFulkerson {
+public final class FordFulkerson {
+    private FordFulkerson() {
+    }
 
     static final int INF = 987654321;
     // edges
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
index 51cd6e50ea43..028c06d38dbd 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
@@ -6,7 +6,9 @@
 /** Program description - To find the maximum subarray sum */
 package com.thealgorithms.dynamicprogramming;
 
-public class KadaneAlgorithm {
+public final class KadaneAlgorithm {
+    private KadaneAlgorithm() {
+    }
 
     public static boolean max_Sum(int[] a, int predicted_answer) {
         int sum = a[0], running_sum = 0;
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
index 5b508e036ae3..c5b7ea2b9a18 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
@@ -11,7 +11,9 @@
    x1 < x2 > x3 < x4 > x5 < …. xn or
    x1 > x2 < x3 > x4 < x5 > …. xn
  */
-public class LongestAlternatingSubsequence {
+public final class LongestAlternatingSubsequence {
+    private LongestAlternatingSubsequence() {
+    }
 
     /* Function to return longest alternating subsequence length*/
     static int AlternatingLength(int[] arr, int n) {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java
index 72fbc89397c0..bf43aab489c9 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.dynamicprogramming;
 
-class LongestCommonSubsequence {
+final class LongestCommonSubsequence {
+    private LongestCommonSubsequence() {
+    }
 
     public static String getLCS(String str1, String str2) {
         // At least one string is null
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
index a0882007dfbd..9457f0bec7e1 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
@@ -5,7 +5,9 @@
 /**
  * @author Afrizal Fikri (https://github.com/icalF)
  */
-public class LongestIncreasingSubsequence {
+public final class LongestIncreasingSubsequence {
+    private LongestIncreasingSubsequence() {
+    }
 
     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java
index c40d91100f30..9dfc6883b16a 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java
@@ -4,7 +4,9 @@
  * Algorithm explanation
  * https://www.educative.io/edpresso/longest-palindromic-subsequence-algorithm
  */
-public class LongestPalindromicSubsequence {
+public final class LongestPalindromicSubsequence {
+    private LongestPalindromicSubsequence() {
+    }
 
     public static void main(String[] args) {
         String a = "BBABCBCAB";
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
index 0704272963fd..489adcca66ed 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
@@ -3,7 +3,9 @@
 /*
  * Algorithm explanation https://leetcode.com/problems/longest-palindromic-substring/
  */
-public class LongestPalindromicSubstring {
+public final class LongestPalindromicSubstring {
+    private LongestPalindromicSubstring() {
+    }
 
     public static void main(String[] args) {
         String a = "babad";
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestValidParentheses.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestValidParentheses.java
index 5ceb85c984ca..02696bfca9c2 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestValidParentheses.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestValidParentheses.java
@@ -7,7 +7,9 @@
  * @author Libin Yang (https://github.com/yanglbme)
  * @since 2018/10/5
  */
-public class LongestValidParentheses {
+public final class LongestValidParentheses {
+    private LongestValidParentheses() {
+    }
 
     public static int getLongestValidParentheses(String s) {
         if (s == null || s.length() < 2) {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
index 3a4b687aea2c..45568d21f295 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
@@ -4,7 +4,9 @@
 import java.util.Arrays;
 import java.util.Scanner;
 
-public class MatrixChainMultiplication {
+public final class MatrixChainMultiplication {
+    private MatrixChainMultiplication() {
+    }
 
     private static final Scanner SCANNER = new Scanner(System.in);
     private static final ArrayList<Matrix> MATRICES = new ArrayList<>();
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java
index ed9ccd8c0073..7d8015a56048 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java
@@ -6,7 +6,9 @@
 // matrix Ai has dimension pi−1 ×pi
 // , fully parenthesize the product A1A2 ···An in a way that
 // minimizes the number of scalar multiplications.
-public class MatrixChainRecursiveTopDownMemoisation {
+public final class MatrixChainRecursiveTopDownMemoisation {
+    private MatrixChainRecursiveTopDownMemoisation() {
+    }
 
     static int Memoized_Matrix_Chain(int[] p) {
         int n = p.length;
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java b/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
index 5aa0bf027c02..ff67500b0585 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
@@ -8,7 +8,9 @@
 
 package com.thealgorithms.dynamicprogramming;
 
-public class NewManShanksPrime {
+public final class NewManShanksPrime {
+    private NewManShanksPrime() {
+    }
 
     public static boolean nthManShanksPrime(int n, int expected_answer) {
         int[] a = new int[n + 1];
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java b/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
index 2ef7d61a355d..2c6643e39c47 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
@@ -17,7 +17,9 @@
  * "aba | b | bbabb | ababa"
  * @author [Syed] (https://github.com/roeticvampire)
  */
-public class PalindromicPartitioning {
+public final class PalindromicPartitioning {
+    private PalindromicPartitioning() {
+    }
 
     public static int minimalpartitions(String word) {
         int len = word.length();
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java b/src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java
index efe5cc883daf..49c4a0a3a008 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java
@@ -18,7 +18,9 @@
 
 import java.util.Arrays;
 
-public class PartitionProblem {
+public final class PartitionProblem {
+    private PartitionProblem() {
+    }
 
     /**
      * Test if a set of integers can be partitioned into two subsets such that the sum of elements
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java b/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java
index cc90e56f1b6d..43427457e307 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java
@@ -12,7 +12,9 @@
  * length of pat
  *
  */
-public class RegexMatching {
+public final class RegexMatching {
+    private RegexMatching() {
+    }
 
     // Method 1: Using Recursion
     // Time Complexity=0(2^(N+M)) Space Complexity=Recursion Extra Space
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java b/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
index 4583aec2e1b4..f56fc4ff5641 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
@@ -4,7 +4,9 @@
  * A Dynamic Programming solution for the Rod cutting problem.
  * Returns the best obtainable price for a rod of length n and price[] as prices of different pieces.
  */
-public class RodCutting {
+public final class RodCutting {
+    private RodCutting() {
+    }
 
     /**
      * This method calculates the maximum obtainable value for cutting a rod of length n
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java b/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
index 78baaa32e1a4..68387b7d2ed7 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
@@ -1,7 +1,9 @@
 package com.thealgorithms.dynamicprogramming;
 
 // Java program to find length of the shortest supersequence
-class ShortestSuperSequence {
+final class ShortestSuperSequence {
+    private ShortestSuperSequence() {
+    }
 
     // Function to find length of the
     // shortest supersequence of X and Y.
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java
index 33696947c008..087d9ac2c7e7 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.dynamicprogramming;
 
-public class SubsetSum {
+public final class SubsetSum {
+    private SubsetSum() {
+    }
 
     /**
      * Driver Code
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java b/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
index 622f8b146d96..a2e641095c9f 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.dynamicprogramming;
 
-public class SumOfSubset {
+public final class SumOfSubset {
+    private SumOfSubset() {
+    }
 
     public static boolean subsetSum(int[] arr, int num, int Key) {
         if (Key == 0) {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java b/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
index 99f9029009ab..6abd6b234195 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
@@ -4,7 +4,9 @@
  * The {@code Tribonacci} class provides a method to compute the n-th number in the Tribonacci sequence.
  * N-th Tribonacci Number - https://leetcode.com/problems/n-th-tribonacci-number/description/
  */
-public class Tribonacci {
+public final class Tribonacci {
+    private Tribonacci() {
+    }
 
     /**
      * Computes the n-th Tribonacci number.
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java b/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java
index a938634cdfd2..8e8bf3cc6606 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java
@@ -14,7 +14,9 @@
 
 package com.thealgorithms.dynamicprogramming;
 
-public class WildcardMatching {
+public final class WildcardMatching {
+    private WildcardMatching() {
+    }
 
     public static boolean isMatch(String text, String pattern) {
         int m = text.length();
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java b/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java
index b7eb029eaa71..6d7f0b8a8036 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java
@@ -10,7 +10,9 @@
  * shelf. You are not allowed to reorder. You have to find the maximum profit
  *
  */
-public class WineProblem {
+public final class WineProblem {
+    private WineProblem() {
+    }
 
     // Method 1: Using Recursion
     // Time Complexity=0(2^N) Space Complexity=Recursion extra space
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java b/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
index 6909c564fe96..88fbc50129ca 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
@@ -6,7 +6,9 @@
 
 // Problem Link:  https://en.wikipedia.org/wiki/Activity_selection_problem
 
-public class ActivitySelection {
+public final class ActivitySelection {
+    private ActivitySelection() {
+    }
     // Function to perform activity selection
     public static ArrayList<Integer> activitySelection(int[] startTimes, int[] endTimes) {
         int n = startTimes.length;
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java b/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
index 560adf8eb84c..8054581d21d7 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
@@ -6,7 +6,9 @@
 
 // Problem Link : https://en.wikipedia.org/wiki/Change-making_problem
 
-public class CoinChange {
+public final class CoinChange {
+    private CoinChange() {
+    }
     // Function to solve the coin change problem
     public static ArrayList<Integer> coinChangeProblem(int amount) {
         // Define an array of coin denominations in descending order
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java b/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
index d13cafb0978a..082bd9c68b32 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
@@ -5,7 +5,9 @@
 
 // Problem Link: https://en.wikipedia.org/wiki/Continuous_knapsack_problem
 
-public class FractionalKnapsack {
+public final class FractionalKnapsack {
+    private FractionalKnapsack() {
+    }
     // Function to perform fractional knapsack
     public static int fractionalKnapsack(int[] weight, int[] value, int capacity) {
         // Create a 2D array to store item indices and their value-to-weight ratios.
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
index 113918263cd3..69d52530d709 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
@@ -5,7 +5,9 @@
 
 // Problem Link: https://en.wikipedia.org/wiki/Job-shop_scheduling
 
-public class JobSequencing {
+public final class JobSequencing {
+    private JobSequencing() {
+    }
 
     // Define a Job class that implements Comparable for sorting by profit in descending order
     static class Job implements Comparable<Job> {
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java b/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java
index 938ae79bb625..c7f219ef3eab 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java
@@ -2,7 +2,9 @@
 
 import java.util.Arrays;
 
-public class MinimizingLateness {
+public final class MinimizingLateness {
+    private MinimizingLateness() {
+    }
 
     public static class Job {
         String jobName;
diff --git a/src/main/java/com/thealgorithms/maths/AbsoluteMax.java b/src/main/java/com/thealgorithms/maths/AbsoluteMax.java
index 64338297e399..d0c3db3790a3 100644
--- a/src/main/java/com/thealgorithms/maths/AbsoluteMax.java
+++ b/src/main/java/com/thealgorithms/maths/AbsoluteMax.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class AbsoluteMax {
+public final class AbsoluteMax {
+    private AbsoluteMax() {
+    }
 
     /**
      * Finds the absolute maximum value among the given numbers.
diff --git a/src/main/java/com/thealgorithms/maths/AbsoluteMin.java b/src/main/java/com/thealgorithms/maths/AbsoluteMin.java
index 97d37dd9294a..1ffe6d2e81bc 100644
--- a/src/main/java/com/thealgorithms/maths/AbsoluteMin.java
+++ b/src/main/java/com/thealgorithms/maths/AbsoluteMin.java
@@ -2,7 +2,9 @@
 
 import java.util.Arrays;
 
-public class AbsoluteMin {
+public final class AbsoluteMin {
+    private AbsoluteMin() {
+    }
 
     /**
      * Compares the numbers given as arguments to get the absolute min value.
diff --git a/src/main/java/com/thealgorithms/maths/AbsoluteValue.java b/src/main/java/com/thealgorithms/maths/AbsoluteValue.java
index 607413641392..b9279d5a244a 100644
--- a/src/main/java/com/thealgorithms/maths/AbsoluteValue.java
+++ b/src/main/java/com/thealgorithms/maths/AbsoluteValue.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class AbsoluteValue {
+public final class AbsoluteValue {
+    private AbsoluteValue() {
+    }
 
     /**
      * Returns the absolute value of a number.
diff --git a/src/main/java/com/thealgorithms/maths/AliquotSum.java b/src/main/java/com/thealgorithms/maths/AliquotSum.java
index daf02f14749f..5a5555777425 100644
--- a/src/main/java/com/thealgorithms/maths/AliquotSum.java
+++ b/src/main/java/com/thealgorithms/maths/AliquotSum.java
@@ -9,7 +9,9 @@
  * are not equal to 15) are 1, 3 and 5, so the aliquot sum of 15 is 9 i.e. (1 +
  * 3 + 5). Wikipedia: https://en.wikipedia.org/wiki/Aliquot_sum
  */
-public class AliquotSum {
+public final class AliquotSum {
+    private AliquotSum() {
+    }
 
     /**
      * Finds the aliquot sum of an integer number.
diff --git a/src/main/java/com/thealgorithms/maths/AmicableNumber.java b/src/main/java/com/thealgorithms/maths/AmicableNumber.java
index 23c90888ec5d..b30831bfdc58 100644
--- a/src/main/java/com/thealgorithms/maths/AmicableNumber.java
+++ b/src/main/java/com/thealgorithms/maths/AmicableNumber.java
@@ -19,7 +19,9 @@
  * 220 is divisible by {1,2,4,5,10,11,20,22,44,55,110} <-SUM = 284
  * 284 is divisible by {1,2,4,71,142} <-SUM = 220.
  */
-public class AmicableNumber {
+public final class AmicableNumber {
+    private AmicableNumber() {
+    }
     /**
      * Finds all the amicable numbers in a given range.
      *
diff --git a/src/main/java/com/thealgorithms/maths/Area.java b/src/main/java/com/thealgorithms/maths/Area.java
index 43d35eea47b9..7a06fd5e5fa0 100644
--- a/src/main/java/com/thealgorithms/maths/Area.java
+++ b/src/main/java/com/thealgorithms/maths/Area.java
@@ -3,7 +3,9 @@
 /**
  * Find the area of various geometric shapes
  */
-public class Area {
+public final class Area {
+    private Area() {
+    }
 
     /**
      * String of IllegalArgumentException for radius
diff --git a/src/main/java/com/thealgorithms/maths/AutoCorrelation.java b/src/main/java/com/thealgorithms/maths/AutoCorrelation.java
index 5b38235bcd01..344a1271e11c 100644
--- a/src/main/java/com/thealgorithms/maths/AutoCorrelation.java
+++ b/src/main/java/com/thealgorithms/maths/AutoCorrelation.java
@@ -7,7 +7,9 @@
  * @version 2.0
  */
 
-public class AutoCorrelation {
+public final class AutoCorrelation {
+    private AutoCorrelation() {
+    }
 
     /**
      * Discrete linear auto-correlation function.
diff --git a/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java b/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
index 1e5eb32f6e8b..d9dd82c7bbe2 100644
--- a/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
+++ b/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
@@ -10,7 +10,9 @@
 
 import java.math.BigInteger;
 
-public class AutomorphicNumber {
+public final class AutomorphicNumber {
+    private AutomorphicNumber() {
+    }
 
     /**
      * A function to check if a number is Automorphic number or not
diff --git a/src/main/java/com/thealgorithms/maths/Average.java b/src/main/java/com/thealgorithms/maths/Average.java
index 903afbafe35f..1c632cf0a65e 100644
--- a/src/main/java/com/thealgorithms/maths/Average.java
+++ b/src/main/java/com/thealgorithms/maths/Average.java
@@ -3,7 +3,9 @@
 /**
  * Calculate average of a list of numbers
  */
-public class Average {
+public final class Average {
+    private Average() {
+    }
 
     /**
      * Calculate average of a list of numbers
diff --git a/src/main/java/com/thealgorithms/maths/BinaryPow.java b/src/main/java/com/thealgorithms/maths/BinaryPow.java
index d431d58b91b1..1550376782b1 100644
--- a/src/main/java/com/thealgorithms/maths/BinaryPow.java
+++ b/src/main/java/com/thealgorithms/maths/BinaryPow.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class BinaryPow {
+public final class BinaryPow {
+    private BinaryPow() {
+    }
 
     /**
      * Calculate a^p using binary exponentiation
diff --git a/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java b/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java
index 4009b79e5057..faec049b08a7 100644
--- a/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java
+++ b/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java
@@ -10,7 +10,9 @@
  *
  * */
 
-public class BinomialCoefficient {
+public final class BinomialCoefficient {
+    private BinomialCoefficient() {
+    }
 
     /**
      * This method returns the number of ways in which k objects can be chosen from n objects
diff --git a/src/main/java/com/thealgorithms/maths/Ceil.java b/src/main/java/com/thealgorithms/maths/Ceil.java
index f9b570fca76a..aacb9d969950 100644
--- a/src/main/java/com/thealgorithms/maths/Ceil.java
+++ b/src/main/java/com/thealgorithms/maths/Ceil.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class Ceil {
+public final class Ceil {
+    private Ceil() {
+    }
 
     /**
      * Returns the smallest (closest to negative infinity)
diff --git a/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java b/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java
index f01e029b42a6..f7010acf452d 100644
--- a/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java
+++ b/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java
@@ -9,7 +9,9 @@
  * @author Ioannis Karavitsis
  * @version 1.0
  */
-public class CircularConvolutionFFT {
+public final class CircularConvolutionFFT {
+    private CircularConvolutionFFT() {
+    }
 
     /**
      * This method pads the signal with zeros until it reaches the new size.
diff --git a/src/main/java/com/thealgorithms/maths/Combinations.java b/src/main/java/com/thealgorithms/maths/Combinations.java
index 68d653229fa9..2b4a78613190 100644
--- a/src/main/java/com/thealgorithms/maths/Combinations.java
+++ b/src/main/java/com/thealgorithms/maths/Combinations.java
@@ -3,7 +3,9 @@
 /**
  * @see <a href="https://en.wikipedia.org/wiki/Combination">Combination</a>
  */
-public class Combinations {
+public final class Combinations {
+    private Combinations() {
+    }
 
     /**
      * Calculate of factorial
diff --git a/src/main/java/com/thealgorithms/maths/Convolution.java b/src/main/java/com/thealgorithms/maths/Convolution.java
index cafb36f7a2b1..4dd4eb3e99f5 100644
--- a/src/main/java/com/thealgorithms/maths/Convolution.java
+++ b/src/main/java/com/thealgorithms/maths/Convolution.java
@@ -6,7 +6,9 @@
  * @author Ioannis Karavitsis
  * @version 1.0
  */
-public class Convolution {
+public final class Convolution {
+    private Convolution() {
+    }
 
     /**
      * Discrete linear convolution function. Both input signals and the output
diff --git a/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java b/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java
index b761092ac70f..ce35b02ca13b 100644
--- a/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java
+++ b/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java
@@ -9,7 +9,9 @@
  * @author Ioannis Karavitsis
  * @version 1.0
  */
-public class ConvolutionFFT {
+public final class ConvolutionFFT {
+    private ConvolutionFFT() {
+    }
 
     /**
      * This method pads the signal with zeros until it reaches the new size.
diff --git a/src/main/java/com/thealgorithms/maths/CrossCorrelation.java b/src/main/java/com/thealgorithms/maths/CrossCorrelation.java
index 080e4ab7e74b..d3a2303502fa 100644
--- a/src/main/java/com/thealgorithms/maths/CrossCorrelation.java
+++ b/src/main/java/com/thealgorithms/maths/CrossCorrelation.java
@@ -7,7 +7,9 @@
  * @version 1.0
  */
 
-public class CrossCorrelation {
+public final class CrossCorrelation {
+    private CrossCorrelation() {
+    }
 
     /**
      * Discrete linear cross-correlation function.
diff --git a/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java b/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
index 53661511aed5..7f96af388611 100644
--- a/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
+++ b/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
@@ -6,7 +6,9 @@
  * @author Ojasva Jain
  * Determinant of a Matrix Wikipedia link: https://en.wikipedia.org/wiki/Determinant
  */
-public class DeterminantOfMatrix {
+public final class DeterminantOfMatrix {
+    private DeterminantOfMatrix() {
+    }
 
     // Determinant calculator
     //@return determinant of the input matrix
diff --git a/src/main/java/com/thealgorithms/maths/DigitalRoot.java b/src/main/java/com/thealgorithms/maths/DigitalRoot.java
index 9eeb4a65f2ae..84b33f34c393 100644
--- a/src/main/java/com/thealgorithms/maths/DigitalRoot.java
+++ b/src/main/java/com/thealgorithms/maths/DigitalRoot.java
@@ -40,7 +40,9 @@
  */
 package com.thealgorithms.maths;
 
-class DigitalRoot {
+final class DigitalRoot {
+    private DigitalRoot() {
+    }
 
     public static int digitalRoot(int n) {
         if (single(n) <= 9) { // If n is already single digit than simply call single method and
diff --git a/src/main/java/com/thealgorithms/maths/DistanceFormula.java b/src/main/java/com/thealgorithms/maths/DistanceFormula.java
index 6efc2fbdff5d..f7e2c7629551 100644
--- a/src/main/java/com/thealgorithms/maths/DistanceFormula.java
+++ b/src/main/java/com/thealgorithms/maths/DistanceFormula.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class DistanceFormula {
+public final class DistanceFormula {
+    private DistanceFormula() {
+    }
 
     public static double euclideanDistance(double x1, double y1, double x2, double y2) {
         double dX = Math.pow(x2 - x1, 2);
diff --git a/src/main/java/com/thealgorithms/maths/DudeneyNumber.java b/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
index 3bb56c5ccdb7..c8c8820d3a5f 100644
--- a/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
@@ -6,7 +6,9 @@
  */
 package com.thealgorithms.maths;
 
-public class DudeneyNumber {
+public final class DudeneyNumber {
+    private DudeneyNumber() {
+    }
 
     // returns True if the number is a Dudeney number and False if it is not a Dudeney number.
     public static boolean isDudeney(int n) {
diff --git a/src/main/java/com/thealgorithms/maths/EulerMethod.java b/src/main/java/com/thealgorithms/maths/EulerMethod.java
index 40e654626a23..3663b6c534aa 100644
--- a/src/main/java/com/thealgorithms/maths/EulerMethod.java
+++ b/src/main/java/com/thealgorithms/maths/EulerMethod.java
@@ -15,7 +15,9 @@
  * https://en.wikipedia.org/wiki/Euler_method ) (see also:
  * https://www.geeksforgeeks.org/euler-method-solving-differential-equation/ )
  */
-public class EulerMethod {
+public final class EulerMethod {
+    private EulerMethod() {
+    }
 
     /**
      * Illustrates how the algorithm is used in 3 examples and prints the
diff --git a/src/main/java/com/thealgorithms/maths/FFT.java b/src/main/java/com/thealgorithms/maths/FFT.java
index f745917749e5..8f21254794c0 100644
--- a/src/main/java/com/thealgorithms/maths/FFT.java
+++ b/src/main/java/com/thealgorithms/maths/FFT.java
@@ -10,7 +10,9 @@
  * @author Ioannis Karavitsis
  * @version 1.0
  */
-public class FFT {
+public final class FFT {
+    private FFT() {
+    }
 
     /**
      * This class represents a complex number and has methods for basic
diff --git a/src/main/java/com/thealgorithms/maths/FFTBluestein.java b/src/main/java/com/thealgorithms/maths/FFTBluestein.java
index cd698b62570a..ca9517eeb673 100644
--- a/src/main/java/com/thealgorithms/maths/FFTBluestein.java
+++ b/src/main/java/com/thealgorithms/maths/FFTBluestein.java
@@ -9,7 +9,9 @@
  * @author Ioannis Karavitsis
  * @version 1.0
  */
-public class FFTBluestein {
+public final class FFTBluestein {
+    private FFTBluestein() {
+    }
 
     /**
      * Bluestein's FFT Algorithm.
diff --git a/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java b/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java
index 886337478d01..a0dbfb1f70a4 100644
--- a/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java
+++ b/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java
@@ -9,7 +9,9 @@
 
 package com.thealgorithms.maths;
 
-public class FastInverseSqrt {
+public final class FastInverseSqrt {
+    private FastInverseSqrt() {
+    }
 
     public static boolean inverseSqrt(float number) {
         float x = number;
diff --git a/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java b/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java
index a9663d39a988..72bae57c27b0 100644
--- a/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java
+++ b/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java
@@ -9,7 +9,9 @@
  * @author: caos321
  * @date: 14 October 2021 (Thursday)
  */
-public class FibonacciJavaStreams {
+public final class FibonacciJavaStreams {
+    private FibonacciJavaStreams() {
+    }
 
     public static Optional<BigDecimal> calculate(final BigDecimal index) {
         if (index == null || index.compareTo(BigDecimal.ZERO) < 0) {
diff --git a/src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java b/src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java
index 937786546fc3..781275d3130d 100644
--- a/src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java
+++ b/src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java
@@ -5,7 +5,9 @@
  * This code checks Fibonacci Numbers up to 45th number.
  * Other checks fail because of 'long'-type overflow.
  */
-public class FibonacciNumberCheck {
+public final class FibonacciNumberCheck {
+    private FibonacciNumberCheck() {
+    }
     /**
      * Check if a number is perfect square number
      *
diff --git a/src/main/java/com/thealgorithms/maths/FindKthNumber.java b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
index 0608cd0f1926..bf7a4985f7f6 100644
--- a/src/main/java/com/thealgorithms/maths/FindKthNumber.java
+++ b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
@@ -6,7 +6,9 @@
 /**
  * use quick sort algorithm to get kth largest or kth smallest element in given array
  */
-public class FindKthNumber {
+public final class FindKthNumber {
+    private FindKthNumber() {
+    }
 
     private static final Random RANDOM = new Random();
 
diff --git a/src/main/java/com/thealgorithms/maths/FrizzyNumber.java b/src/main/java/com/thealgorithms/maths/FrizzyNumber.java
index 3b1ff5fde3b3..3ae5e021df1b 100644
--- a/src/main/java/com/thealgorithms/maths/FrizzyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/FrizzyNumber.java
@@ -7,7 +7,9 @@
 
 package com.thealgorithms.maths;
 
-public class FrizzyNumber {
+public final class FrizzyNumber {
+    private FrizzyNumber() {
+    }
 
     /**
      * Returns the n-th number that is a sum of powers
diff --git a/src/main/java/com/thealgorithms/maths/GCD.java b/src/main/java/com/thealgorithms/maths/GCD.java
index 0f3125bde209..5156e4ac881d 100644
--- a/src/main/java/com/thealgorithms/maths/GCD.java
+++ b/src/main/java/com/thealgorithms/maths/GCD.java
@@ -6,7 +6,9 @@
  *
  * @author Oskar Enmalm 3/10/17
  */
-public class GCD {
+public final class GCD {
+    private GCD() {
+    }
 
     /**
      * get the greatest common divisor
diff --git a/src/main/java/com/thealgorithms/maths/GCDRecursion.java b/src/main/java/com/thealgorithms/maths/GCDRecursion.java
index 05e44f941ac7..e95ce97c8a04 100644
--- a/src/main/java/com/thealgorithms/maths/GCDRecursion.java
+++ b/src/main/java/com/thealgorithms/maths/GCDRecursion.java
@@ -3,7 +3,9 @@
 /**
  * @author https://github.com/shellhub/
  */
-public class GCDRecursion {
+public final class GCDRecursion {
+    private GCDRecursion() {
+    }
 
     public static void main(String[] args) {
         System.out.println(gcd(20, 15));
diff --git a/src/main/java/com/thealgorithms/maths/Gaussian.java b/src/main/java/com/thealgorithms/maths/Gaussian.java
index 442c51e9d32d..5591bfd1068c 100644
--- a/src/main/java/com/thealgorithms/maths/Gaussian.java
+++ b/src/main/java/com/thealgorithms/maths/Gaussian.java
@@ -2,7 +2,9 @@
 
 import java.util.ArrayList;
 
-public class Gaussian {
+public final class Gaussian {
+    private Gaussian() {
+    }
 
     public static ArrayList<Double> gaussian(int mat_size, ArrayList<Double> matrix) {
         ArrayList<Double> answerArray = new ArrayList<Double>();
diff --git a/src/main/java/com/thealgorithms/maths/HarshadNumber.java b/src/main/java/com/thealgorithms/maths/HarshadNumber.java
index 4778dc81b664..e063c860ca6a 100644
--- a/src/main/java/com/thealgorithms/maths/HarshadNumber.java
+++ b/src/main/java/com/thealgorithms/maths/HarshadNumber.java
@@ -2,7 +2,9 @@
 
 // Wikipedia for Harshad Number : https://en.wikipedia.org/wiki/Harshad_number
 
-public class HarshadNumber {
+public final class HarshadNumber {
+    private HarshadNumber() {
+    }
 
     /**
      * A function to check if a number is Harshad number or not
diff --git a/src/main/java/com/thealgorithms/maths/JosephusProblem.java b/src/main/java/com/thealgorithms/maths/JosephusProblem.java
index b878eff2b291..7d19623b3ed0 100644
--- a/src/main/java/com/thealgorithms/maths/JosephusProblem.java
+++ b/src/main/java/com/thealgorithms/maths/JosephusProblem.java
@@ -20,7 +20,9 @@
         @author Kunal
     */
 
-public class JosephusProblem {
+public final class JosephusProblem {
+    private JosephusProblem() {
+    }
 
     /**
      * Find the Winner of the Circular Game.
diff --git a/src/main/java/com/thealgorithms/maths/JugglerSequence.java b/src/main/java/com/thealgorithms/maths/JugglerSequence.java
index 216098fc926f..702310a1f295 100644
--- a/src/main/java/com/thealgorithms/maths/JugglerSequence.java
+++ b/src/main/java/com/thealgorithms/maths/JugglerSequence.java
@@ -11,7 +11,9 @@
  *
  * */
 
-public class JugglerSequence {
+public final class JugglerSequence {
+    private JugglerSequence() {
+    }
 
     /**
      * This method prints juggler sequence starting with the number in the parameter
diff --git a/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java b/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
index e46a3ac8374d..f025f86682a2 100644
--- a/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
+++ b/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
@@ -4,7 +4,9 @@
 import java.util.ArrayList;
 import java.util.List;
 
-public class KaprekarNumbers {
+public final class KaprekarNumbers {
+    private KaprekarNumbers() {
+    }
 
     /* This program demonstrates if a given number is Kaprekar Number or not.
         Kaprekar Number: A Kaprekar number is an n-digit number which its square can be split into
diff --git a/src/main/java/com/thealgorithms/maths/KeithNumber.java b/src/main/java/com/thealgorithms/maths/KeithNumber.java
index fdabbc16685d..194c4ba3c5bd 100644
--- a/src/main/java/com/thealgorithms/maths/KeithNumber.java
+++ b/src/main/java/com/thealgorithms/maths/KeithNumber.java
@@ -4,7 +4,9 @@
 import java.util.Collections;
 import java.util.Scanner;
 
-class KeithNumber {
+final class KeithNumber {
+    private KeithNumber() {
+    }
 
     // user-defined function that checks if the given number is Keith or not
     static boolean isKeith(int x) {
diff --git a/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java b/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
index f152b0666a10..f5ff50337bc7 100644
--- a/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
@@ -9,7 +9,9 @@
 import java.io.IOException;
 import java.io.InputStreamReader;
 
-public class KrishnamurthyNumber {
+public final class KrishnamurthyNumber {
+    private KrishnamurthyNumber() {
+    }
 
     // returns True if the number is a Krishnamurthy number and False if it is not.
 
diff --git a/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java b/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
index 66352568f96d..ae887470fa33 100644
--- a/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
+++ b/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
@@ -9,7 +9,9 @@
  * @author LauKinHoong
  */
 
-public class LeastCommonMultiple {
+public final class LeastCommonMultiple {
+    private LeastCommonMultiple() {
+    }
 
     /**
      * Driver Code
diff --git a/src/main/java/com/thealgorithms/maths/LeonardoNumber.java b/src/main/java/com/thealgorithms/maths/LeonardoNumber.java
index 1ca5c8bd0fa6..bbeec052777f 100644
--- a/src/main/java/com/thealgorithms/maths/LeonardoNumber.java
+++ b/src/main/java/com/thealgorithms/maths/LeonardoNumber.java
@@ -3,7 +3,9 @@
 /**
  * https://en.wikipedia.org/wiki/Leonardo_number
  */
-public class LeonardoNumber {
+public final class LeonardoNumber {
+    private LeonardoNumber() {
+    }
 
     /**
      * Calculate nth Leonardo Number (1, 1, 3, 5, 9, 15, 25, 41, 67, 109, 177, ...)
diff --git a/src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java b/src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java
index 2d00cc5561e8..a50cfb218283 100644
--- a/src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java
+++ b/src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java
@@ -3,6 +3,8 @@
 import java.util.Objects;
 
 public final class LinearDiophantineEquationsSolver {
+    private LinearDiophantineEquationsSolver() {
+    }
 
     public static void main(String[] args) {
         // 3x + 4y = 7
diff --git a/src/main/java/com/thealgorithms/maths/LiouvilleLambdaFunction.java b/src/main/java/com/thealgorithms/maths/LiouvilleLambdaFunction.java
index 89acbf6a14e7..c0f55f5e3485 100644
--- a/src/main/java/com/thealgorithms/maths/LiouvilleLambdaFunction.java
+++ b/src/main/java/com/thealgorithms/maths/LiouvilleLambdaFunction.java
@@ -12,7 +12,9 @@
  *
  * */
 
-public class LiouvilleLambdaFunction {
+public final class LiouvilleLambdaFunction {
+    private LiouvilleLambdaFunction() {
+    }
 
     /**
      * This method returns λ(n) of given number n
diff --git a/src/main/java/com/thealgorithms/maths/LongDivision.java b/src/main/java/com/thealgorithms/maths/LongDivision.java
index b1c7b1901701..2191bf840a9b 100644
--- a/src/main/java/com/thealgorithms/maths/LongDivision.java
+++ b/src/main/java/com/thealgorithms/maths/LongDivision.java
@@ -8,7 +8,9 @@
 
 package com.thealgorithms.maths;
 
-public class LongDivision {
+public final class LongDivision {
+    private LongDivision() {
+    }
     public static int divide(int dividend, int divisor) {
         long new_dividend_1 = dividend;
         long new_divisor_1 = divisor;
diff --git a/src/main/java/com/thealgorithms/maths/LucasSeries.java b/src/main/java/com/thealgorithms/maths/LucasSeries.java
index ebeb2715fe2d..e277c511f317 100644
--- a/src/main/java/com/thealgorithms/maths/LucasSeries.java
+++ b/src/main/java/com/thealgorithms/maths/LucasSeries.java
@@ -3,7 +3,9 @@
 /**
  * https://en.wikipedia.org/wiki/Lucas_number
  */
-public class LucasSeries {
+public final class LucasSeries {
+    private LucasSeries() {
+    }
 
     /**
      * Calculate nth number of Lucas Series(2, 1, 3, 4, 7, 11, 18, 29, 47, 76,
diff --git a/src/main/java/com/thealgorithms/maths/MagicSquare.java b/src/main/java/com/thealgorithms/maths/MagicSquare.java
index 6e9f88a5a0b9..7e0ff4da6da7 100644
--- a/src/main/java/com/thealgorithms/maths/MagicSquare.java
+++ b/src/main/java/com/thealgorithms/maths/MagicSquare.java
@@ -5,7 +5,9 @@
 /*A magic square of order n is an arrangement of distinct n^2 integers,in a square, such that the n
 numbers in all rows, all columns, and both diagonals sum to the same constant. A magic square
 contains the integers from 1 to n^2.*/
-public class MagicSquare {
+public final class MagicSquare {
+    private MagicSquare() {
+    }
 
     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/maths/MatrixUtil.java b/src/main/java/com/thealgorithms/maths/MatrixUtil.java
index f3d0efeacc45..0759853d61a9 100644
--- a/src/main/java/com/thealgorithms/maths/MatrixUtil.java
+++ b/src/main/java/com/thealgorithms/maths/MatrixUtil.java
@@ -11,7 +11,9 @@
  * @author: caos321
  * @date: 31 October 2021 (Sunday)
  */
-public class MatrixUtil {
+public final class MatrixUtil {
+    private MatrixUtil() {
+    }
 
     public static boolean isValid(final BigDecimal[][] matrix) {
         return matrix != null && matrix.length > 0 && matrix[0].length > 0;
diff --git a/src/main/java/com/thealgorithms/maths/Median.java b/src/main/java/com/thealgorithms/maths/Median.java
index 89bc42254d34..e4daec8fc11a 100644
--- a/src/main/java/com/thealgorithms/maths/Median.java
+++ b/src/main/java/com/thealgorithms/maths/Median.java
@@ -5,7 +5,9 @@
 /**
  * Wikipedia: https://en.wikipedia.org/wiki/Median
  */
-public class Median {
+public final class Median {
+    private Median() {
+    }
 
     /**
      * Calculate average median
diff --git a/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java b/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java
index ed4f325b0710..e25836f713a9 100644
--- a/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java
+++ b/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java
@@ -2,7 +2,9 @@
 
 import java.util.Random;
 
-public class MillerRabinPrimalityCheck {
+public final class MillerRabinPrimalityCheck {
+    private MillerRabinPrimalityCheck() {
+    }
 
     /**
      * Check whether the given number is prime or not
diff --git a/src/main/java/com/thealgorithms/maths/MobiusFunction.java b/src/main/java/com/thealgorithms/maths/MobiusFunction.java
index e9ead992d7a7..915d0d9a6dae 100644
--- a/src/main/java/com/thealgorithms/maths/MobiusFunction.java
+++ b/src/main/java/com/thealgorithms/maths/MobiusFunction.java
@@ -12,7 +12,9 @@
  * Author: Akshay Dubey (https://github.com/itsAkshayDubey)
  *
  * */
-public class MobiusFunction {
+public final class MobiusFunction {
+    private MobiusFunction() {
+    }
 
     /**
      * This method returns μ(n) of given number n
diff --git a/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java b/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
index 01fdd5a6a5a5..ee92470ca35f 100644
--- a/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
+++ b/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
@@ -7,7 +7,9 @@
  * Reason to use bitwise operator: It makes our program faster as we are operating on bits and not
  * on actual numbers.
  */
-public class NonRepeatingElement {
+public final class NonRepeatingElement {
+    private NonRepeatingElement() {
+    }
 
     public static void main(String[] args) {
         try (Scanner sc = new Scanner(System.in)) {
diff --git a/src/main/java/com/thealgorithms/maths/PalindromeNumber.java b/src/main/java/com/thealgorithms/maths/PalindromeNumber.java
index 5dad99ef30e0..a22d63897b37 100644
--- a/src/main/java/com/thealgorithms/maths/PalindromeNumber.java
+++ b/src/main/java/com/thealgorithms/maths/PalindromeNumber.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class PalindromeNumber {
+public final class PalindromeNumber {
+    private PalindromeNumber() {
+    }
     /**
      * Check if {@code n} is palindrome number or not
      *
diff --git a/src/main/java/com/thealgorithms/maths/PascalTriangle.java b/src/main/java/com/thealgorithms/maths/PascalTriangle.java
index beb9a1e4937e..ef6aa41d6e53 100644
--- a/src/main/java/com/thealgorithms/maths/PascalTriangle.java
+++ b/src/main/java/com/thealgorithms/maths/PascalTriangle.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class PascalTriangle {
+public final class PascalTriangle {
+    private PascalTriangle() {
+    }
 
     /**
      *In mathematics, Pascal's triangle is a triangular array of the binomial coefficients that
diff --git a/src/main/java/com/thealgorithms/maths/PerfectCube.java b/src/main/java/com/thealgorithms/maths/PerfectCube.java
index f9ed0558b8d5..4104c6238580 100644
--- a/src/main/java/com/thealgorithms/maths/PerfectCube.java
+++ b/src/main/java/com/thealgorithms/maths/PerfectCube.java
@@ -3,7 +3,9 @@
 /**
  * https://en.wikipedia.org/wiki/Cube_(algebra)
  */
-public class PerfectCube {
+public final class PerfectCube {
+    private PerfectCube() {
+    }
 
     /**
      * Check if a number is perfect cube or not
diff --git a/src/main/java/com/thealgorithms/maths/PerfectNumber.java b/src/main/java/com/thealgorithms/maths/PerfectNumber.java
index 7d6a045166e5..49afd23f91bf 100644
--- a/src/main/java/com/thealgorithms/maths/PerfectNumber.java
+++ b/src/main/java/com/thealgorithms/maths/PerfectNumber.java
@@ -8,7 +8,9 @@
  *
  * link:https://en.wikipedia.org/wiki/Perfect_number
  */
-public class PerfectNumber {
+public final class PerfectNumber {
+    private PerfectNumber() {
+    }
 
     /**
      * Check if {@code number} is perfect number or not
diff --git a/src/main/java/com/thealgorithms/maths/Perimeter.java b/src/main/java/com/thealgorithms/maths/Perimeter.java
index e3476afaf0b3..f8aa1876d388 100644
--- a/src/main/java/com/thealgorithms/maths/Perimeter.java
+++ b/src/main/java/com/thealgorithms/maths/Perimeter.java
@@ -1,7 +1,9 @@
 package com.thealgorithms.maths;
 
 // Perimeter of different 2D geometrical shapes
-public class Perimeter {
+public final class Perimeter {
+    private Perimeter() {
+    }
 
     /**
      * Calculate the Perimeter of regular polygon (equals sides)
diff --git a/src/main/java/com/thealgorithms/maths/PiNilakantha.java b/src/main/java/com/thealgorithms/maths/PiNilakantha.java
index d00240317997..6d43f134c94c 100644
--- a/src/main/java/com/thealgorithms/maths/PiNilakantha.java
+++ b/src/main/java/com/thealgorithms/maths/PiNilakantha.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class PiNilakantha {
+public final class PiNilakantha {
+    private PiNilakantha() {
+    }
 
     // Calculates Pi using Nilakantha's infinite series
     // Method 2 in the following link explains the algorithm
diff --git a/src/main/java/com/thealgorithms/maths/PollardRho.java b/src/main/java/com/thealgorithms/maths/PollardRho.java
index 8ce62336061e..8855a463e81c 100644
--- a/src/main/java/com/thealgorithms/maths/PollardRho.java
+++ b/src/main/java/com/thealgorithms/maths/PollardRho.java
@@ -35,7 +35,9 @@
  * Author: Akshay Dubey (https://github.com/itsAkshayDubey)
  *
  * */
-public class PollardRho {
+public final class PollardRho {
+    private PollardRho() {
+    }
 
     /**
      * This method returns a polynomial in x computed modulo n
diff --git a/src/main/java/com/thealgorithms/maths/Pow.java b/src/main/java/com/thealgorithms/maths/Pow.java
index 1d8ff2931ee0..3f362fe88d30 100644
--- a/src/main/java/com/thealgorithms/maths/Pow.java
+++ b/src/main/java/com/thealgorithms/maths/Pow.java
@@ -1,7 +1,9 @@
 package com.thealgorithms.maths;
 
 // POWER (exponentials) Examples (a^b)
-public class Pow {
+public final class Pow {
+    private Pow() {
+    }
 
     public static void main(String[] args) {
         assert pow(2, 0) == Math.pow(2, 0); // == 1
diff --git a/src/main/java/com/thealgorithms/maths/PowerUsingRecursion.java b/src/main/java/com/thealgorithms/maths/PowerUsingRecursion.java
index cbb2d6132366..93c8252ab929 100644
--- a/src/main/java/com/thealgorithms/maths/PowerUsingRecursion.java
+++ b/src/main/java/com/thealgorithms/maths/PowerUsingRecursion.java
@@ -5,7 +5,9 @@
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
 
-public class PowerUsingRecursion {
+public final class PowerUsingRecursion {
+    private PowerUsingRecursion() {
+    }
 
     public static double power(double base, int exponent) {
         // Base case: anything raised to the power of 0 is 1
diff --git a/src/main/java/com/thealgorithms/maths/PrimeCheck.java b/src/main/java/com/thealgorithms/maths/PrimeCheck.java
index 2c9714f1335b..4f928bfe451e 100644
--- a/src/main/java/com/thealgorithms/maths/PrimeCheck.java
+++ b/src/main/java/com/thealgorithms/maths/PrimeCheck.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-public class PrimeCheck {
+public final class PrimeCheck {
+    private PrimeCheck() {
+    }
 
     public static void main(String[] args) {
         Scanner scanner = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/maths/PrimeFactorization.java b/src/main/java/com/thealgorithms/maths/PrimeFactorization.java
index 7e13cc673cd4..9ac50fd9043b 100644
--- a/src/main/java/com/thealgorithms/maths/PrimeFactorization.java
+++ b/src/main/java/com/thealgorithms/maths/PrimeFactorization.java
@@ -9,7 +9,9 @@
 import java.util.ArrayList;
 import java.util.List;
 
-public class PrimeFactorization {
+public final class PrimeFactorization {
+    private PrimeFactorization() {
+    }
 
     public static List<Integer> pfactors(int n) {
         List<Integer> primeFactors = new ArrayList<>();
diff --git a/src/main/java/com/thealgorithms/maths/PronicNumber.java b/src/main/java/com/thealgorithms/maths/PronicNumber.java
index 312af21ea2ba..1ae53c4c4429 100644
--- a/src/main/java/com/thealgorithms/maths/PronicNumber.java
+++ b/src/main/java/com/thealgorithms/maths/PronicNumber.java
@@ -10,7 +10,9 @@
  *
  * */
 
-public class PronicNumber {
+public final class PronicNumber {
+    private PronicNumber() {
+    }
 
     /**
      * This method checks if the given number is pronic number or non-pronic number
diff --git a/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java b/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java
index 68932c0b76bd..f535e9e6929b 100644
--- a/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java
+++ b/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java
@@ -3,7 +3,9 @@
 /**
  * https://en.wikipedia.org/wiki/Pythagorean_triple
  */
-public class PythagoreanTriple {
+public final class PythagoreanTriple {
+    private PythagoreanTriple() {
+    }
 
     public static void main(String[] args) {
         assert isPythagTriple(3, 4, 5);
diff --git a/src/main/java/com/thealgorithms/maths/RomanNumeralUtil.java b/src/main/java/com/thealgorithms/maths/RomanNumeralUtil.java
index 0caa286231b6..8f5d44dbe146 100644
--- a/src/main/java/com/thealgorithms/maths/RomanNumeralUtil.java
+++ b/src/main/java/com/thealgorithms/maths/RomanNumeralUtil.java
@@ -8,7 +8,9 @@
  * @author Sokratis Fotkatzikis
  * @version 1.0
  */
-public class RomanNumeralUtil {
+public final class RomanNumeralUtil {
+    private RomanNumeralUtil() {
+    }
 
     private static final int MIN_VALUE = 1;
     private static final int MAX_VALUE = 5999;
diff --git a/src/main/java/com/thealgorithms/maths/SquareFreeInteger.java b/src/main/java/com/thealgorithms/maths/SquareFreeInteger.java
index c988bb70808c..22e9fee00605 100644
--- a/src/main/java/com/thealgorithms/maths/SquareFreeInteger.java
+++ b/src/main/java/com/thealgorithms/maths/SquareFreeInteger.java
@@ -14,7 +14,9 @@
 import java.util.HashSet;
 import java.util.List;
 
-public class SquareFreeInteger {
+public final class SquareFreeInteger {
+    private SquareFreeInteger() {
+    }
     /**
      * This method returns whether an integer is square free
      *
diff --git a/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java b/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java
index 2f8fa9a83885..90af556f8e23 100644
--- a/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java
+++ b/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class SquareRootWithBabylonianMethod {
+public final class SquareRootWithBabylonianMethod {
+    private SquareRootWithBabylonianMethod() {
+    }
 
     /**
      * get the value, return the square root
diff --git a/src/main/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonMethod.java b/src/main/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonMethod.java
index eb116d21ac36..80d185c93785 100644
--- a/src/main/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonMethod.java
+++ b/src/main/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonMethod.java
@@ -14,7 +14,9 @@
  * be changed according to the user preference.
  */
 
-public class SquareRootWithNewtonRaphsonMethod {
+public final class SquareRootWithNewtonRaphsonMethod {
+    private SquareRootWithNewtonRaphsonMethod() {
+    }
 
     public static double squareRoot(int n) {
         double x = n; // initially taking a guess that x = n.
diff --git a/src/main/java/com/thealgorithms/maths/StandardDeviation.java b/src/main/java/com/thealgorithms/maths/StandardDeviation.java
index 84d21f3082f0..29ff070e9cff 100644
--- a/src/main/java/com/thealgorithms/maths/StandardDeviation.java
+++ b/src/main/java/com/thealgorithms/maths/StandardDeviation.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class StandardDeviation {
+public final class StandardDeviation {
+    private StandardDeviation() {
+    }
 
     public static double stdDev(double[] data) {
         double var = 0;
diff --git a/src/main/java/com/thealgorithms/maths/StandardScore.java b/src/main/java/com/thealgorithms/maths/StandardScore.java
index dcedf458b09e..22a9f550e114 100644
--- a/src/main/java/com/thealgorithms/maths/StandardScore.java
+++ b/src/main/java/com/thealgorithms/maths/StandardScore.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.maths;
 
-public class StandardScore {
+public final class StandardScore {
+    private StandardScore() {
+    }
 
     public static double zScore(double num, double mean, double stdDev) {
         return (num - mean) / stdDev;
diff --git a/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java b/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java
index 0e2fe9e7a46a..c2a173000a78 100644
--- a/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java
+++ b/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java
@@ -7,7 +7,9 @@
  *
  * Example Input: n = 4 Output 1 1 1 1 1 2 3 2 1 1 3 6 7 6 3 1
  */
-public class TrinomialTriangle {
+public final class TrinomialTriangle {
+    private TrinomialTriangle() {
+    }
 
     public static int TrinomialValue(int n, int k) {
         if (n == 0 && k == 0) {
diff --git a/src/main/java/com/thealgorithms/maths/TwinPrime.java b/src/main/java/com/thealgorithms/maths/TwinPrime.java
index 867a1d23f220..81731376b37a 100644
--- a/src/main/java/com/thealgorithms/maths/TwinPrime.java
+++ b/src/main/java/com/thealgorithms/maths/TwinPrime.java
@@ -9,7 +9,9 @@
  *
  * */
 
-public class TwinPrime {
+public final class TwinPrime {
+    private TwinPrime() {
+    }
 
     /**
      * This method returns twin prime of the integer value passed as argument
diff --git a/src/main/java/com/thealgorithms/maths/VampireNumber.java b/src/main/java/com/thealgorithms/maths/VampireNumber.java
index d9aa4f203550..d64c82c6e68e 100644
--- a/src/main/java/com/thealgorithms/maths/VampireNumber.java
+++ b/src/main/java/com/thealgorithms/maths/VampireNumber.java
@@ -16,7 +16,9 @@
  *
  * <p>
  */
-public class VampireNumber {
+public final class VampireNumber {
+    private VampireNumber() {
+    }
 
     public static void main(String[] args) {
         test(10, 1000);
diff --git a/src/main/java/com/thealgorithms/maths/Volume.java b/src/main/java/com/thealgorithms/maths/Volume.java
index edc3575dfda6..4b73f849bb81 100644
--- a/src/main/java/com/thealgorithms/maths/Volume.java
+++ b/src/main/java/com/thealgorithms/maths/Volume.java
@@ -1,7 +1,9 @@
 package com.thealgorithms.maths;
 
 /* Calculate the volume of various shapes.*/
-public class Volume {
+public final class Volume {
+    private Volume() {
+    }
 
     /**
      * Calculate the volume of a cube.
diff --git a/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java b/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java
index b2e4576b6179..afd34933047a 100644
--- a/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java
+++ b/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java
@@ -7,7 +7,9 @@
  * see https://www.geeksforgeeks.org/matrix-exponentiation/
  *
  */
-public class Fibonacci {
+public final class Fibonacci {
+    private Fibonacci() {
+    }
 
     // Exponentiation matrix for Fibonacci sequence
     private static final int[][] FIB_MATRIX = {{1, 1}, {1, 0}};
diff --git a/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java b/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java
index 0fb5b6f17b97..5543463e9749 100644
--- a/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java
+++ b/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java
@@ -11,7 +11,9 @@
  *
  * We can also find the inverse of a matrix
  */
-public class InverseOfMatrix {
+public final class InverseOfMatrix {
+    private InverseOfMatrix() {
+    }
 
     public static void main(String[] argv) {
         Scanner input = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/misc/MapReduce.java b/src/main/java/com/thealgorithms/misc/MapReduce.java
index baf960f8ecef..c076957344f9 100644
--- a/src/main/java/com/thealgorithms/misc/MapReduce.java
+++ b/src/main/java/com/thealgorithms/misc/MapReduce.java
@@ -15,7 +15,9 @@
 * Wikipedia link : https://en.wikipedia.org/wiki/MapReduce
 */
 
-public class MapReduce {
+public final class MapReduce {
+    private MapReduce() {
+    }
     /*
      *Counting all the words frequency within a sentence.
      */
diff --git a/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java b/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
index 4d8b980f2409..d4ddffe8ddd7 100644
--- a/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
+++ b/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
@@ -10,6 +10,8 @@
  */
 
 public final class MedianOfMatrix {
+    private MedianOfMatrix() {
+    }
 
     public static int median(List<List<Integer>> matrix) {
         // Flatten the matrix into a 1D list
diff --git a/src/main/java/com/thealgorithms/misc/PalindromePrime.java b/src/main/java/com/thealgorithms/misc/PalindromePrime.java
index 58de938394af..6b01cdced23c 100644
--- a/src/main/java/com/thealgorithms/misc/PalindromePrime.java
+++ b/src/main/java/com/thealgorithms/misc/PalindromePrime.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-public class PalindromePrime {
+public final class PalindromePrime {
+    private PalindromePrime() {
+    }
 
     public static void main(String[] args) { // Main funtion
         Scanner in = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java b/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
index f70a443e96e4..0dfc8ac32a6f 100644
--- a/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
+++ b/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
@@ -2,7 +2,9 @@
 
 import java.util.Arrays;
 
-public class RangeInSortedArray {
+public final class RangeInSortedArray {
+    private RangeInSortedArray() {
+    }
 
     public static void main(String[] args) {
         // Testcases
diff --git a/src/main/java/com/thealgorithms/misc/Sort012D.java b/src/main/java/com/thealgorithms/misc/Sort012D.java
index a311dac447ed..b51664ce7a5a 100644
--- a/src/main/java/com/thealgorithms/misc/Sort012D.java
+++ b/src/main/java/com/thealgorithms/misc/Sort012D.java
@@ -11,7 +11,9 @@
  * For more information on the Dutch national flag algorithm refer
  * https://en.wikipedia.org/wiki/Dutch_national_flag_problem
  */
-public class Sort012D {
+public final class Sort012D {
+    private Sort012D() {
+    }
 
     public static void main(String[] args) {
         Scanner np = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/misc/Sparcity.java b/src/main/java/com/thealgorithms/misc/Sparsity.java
similarity index 82%
rename from src/main/java/com/thealgorithms/misc/Sparcity.java
rename to src/main/java/com/thealgorithms/misc/Sparsity.java
index 10b6f58096c3..cae2fbdead94 100644
--- a/src/main/java/com/thealgorithms/misc/Sparcity.java
+++ b/src/main/java/com/thealgorithms/misc/Sparsity.java
@@ -11,15 +11,17 @@
  * @author Ojasva Jain
  */
 
-class Sparcity {
+final class Sparsity {
+    private Sparsity() {
+    }
 
     /*
-     * @return Sparcity of matrix
+     * @return Sparsity of matrix
      *
-     * where sparcity = number of zeroes/total elements in matrix
+     * where sparsity = number of zeroes/total elements in matrix
      *
      */
-    static double sparcity(double[][] mat) {
+    static double sparsity(double[][] mat) {
         int zero = 0;
         // Traversing the matrix to count number of zeroes
         for (int i = 0; i < mat.length; i++) {
@@ -29,7 +31,7 @@ static double sparcity(double[][] mat) {
                 }
             }
         }
-        // return sparcity
+        // return sparsity
         return ((double) zero / (mat.length * mat[1].length));
     }
 
@@ -48,7 +50,7 @@ public static void main(String[] args) {
                 mat[i][j] = in.nextDouble();
             }
         }
-        System.out.println("Sparcity of matrix is: " + sparcity(mat));
+        System.out.println("Sparsity of matrix is: " + sparsity(mat));
         in.close();
     }
 }
diff --git a/src/main/java/com/thealgorithms/misc/WordBoggle.java b/src/main/java/com/thealgorithms/misc/WordBoggle.java
index b56b907de935..3eb0dc95ffb5 100644
--- a/src/main/java/com/thealgorithms/misc/WordBoggle.java
+++ b/src/main/java/com/thealgorithms/misc/WordBoggle.java
@@ -8,7 +8,9 @@
 import java.util.Map;
 import java.util.Set;
 
-public class WordBoggle {
+public final class WordBoggle {
+    private WordBoggle() {
+    }
 
     /**
      * O(nm * 8^s + ws) time where n = width of boggle board, m = height of
diff --git a/src/main/java/com/thealgorithms/misc/matrixTranspose.java b/src/main/java/com/thealgorithms/misc/matrixTranspose.java
index b5ad02184a00..bf81675af641 100644
--- a/src/main/java/com/thealgorithms/misc/matrixTranspose.java
+++ b/src/main/java/com/thealgorithms/misc/matrixTranspose.java
@@ -18,7 +18,9 @@
  * @version 11.0.9
  * @since 2014-03-31
  */
-public class matrixTranspose {
+public final class matrixTranspose {
+    private matrixTranspose() {
+    }
 
     public static void main(String[] args) {
         /*
diff --git a/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java b/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java
index 4ee54bbdacf8..f43841f1f184 100644
--- a/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java
+++ b/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java
@@ -8,7 +8,9 @@
  * @author sangin-lee
  */
 
-public class ArrayLeftRotation {
+public final class ArrayLeftRotation {
+    private ArrayLeftRotation() {
+    }
 
     /*
      * Returns the result of left rotation of given array arr and integer n
diff --git a/src/main/java/com/thealgorithms/others/BFPRT.java b/src/main/java/com/thealgorithms/others/BFPRT.java
index 29f47cd68ed6..9e6fe6a3fbcc 100644
--- a/src/main/java/com/thealgorithms/others/BFPRT.java
+++ b/src/main/java/com/thealgorithms/others/BFPRT.java
@@ -5,7 +5,9 @@
 /**
  * BFPRT algorithm.
  */
-public class BFPRT {
+public final class BFPRT {
+    private BFPRT() {
+    }
 
     public static int[] getMinKNumsByBFPRT(int[] arr, int k) {
         if (k < 1 || k > arr.length) {
diff --git a/src/main/java/com/thealgorithms/others/BankersAlgorithm.java b/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
index 3fbb4f9fda68..fb699d89c379 100644
--- a/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
@@ -20,7 +20,9 @@
  */
 import java.util.Scanner;
 
-public class BankersAlgorithm {
+public final class BankersAlgorithm {
+    private BankersAlgorithm() {
+    }
 
     /**
      * This method finds the need of each process
diff --git a/src/main/java/com/thealgorithms/others/BrianKernighanAlgorithm.java b/src/main/java/com/thealgorithms/others/BrianKernighanAlgorithm.java
index a1983feccb2e..b70fffe82c5b 100644
--- a/src/main/java/com/thealgorithms/others/BrianKernighanAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/BrianKernighanAlgorithm.java
@@ -20,7 +20,9 @@
  * <p>
  * Time Complexity: O(logn)
  */
-public class BrianKernighanAlgorithm {
+public final class BrianKernighanAlgorithm {
+    private BrianKernighanAlgorithm() {
+    }
 
     /**
      * @param num: number in which we count the set bits
diff --git a/src/main/java/com/thealgorithms/others/CRC16.java b/src/main/java/com/thealgorithms/others/CRC16.java
index c5c3b1f35a7d..85e5cd2c13ae 100644
--- a/src/main/java/com/thealgorithms/others/CRC16.java
+++ b/src/main/java/com/thealgorithms/others/CRC16.java
@@ -3,7 +3,9 @@
 /**
  * Generates a crc16 checksum for a given string
  */
-public class CRC16 {
+public final class CRC16 {
+    private CRC16() {
+    }
 
     public static void main(String[] args) {
         System.out.println(crc16("Hello World!"));
diff --git a/src/main/java/com/thealgorithms/others/CRC32.java b/src/main/java/com/thealgorithms/others/CRC32.java
index 561a33f4dae9..180936ed46c1 100644
--- a/src/main/java/com/thealgorithms/others/CRC32.java
+++ b/src/main/java/com/thealgorithms/others/CRC32.java
@@ -5,7 +5,9 @@
 /**
  * Generates a crc32 checksum for a given string or byte array
  */
-public class CRC32 {
+public final class CRC32 {
+    private CRC32() {
+    }
 
     public static void main(String[] args) {
         System.out.println(Integer.toHexString(crc32("Hello World")));
diff --git a/src/main/java/com/thealgorithms/others/Conway.java b/src/main/java/com/thealgorithms/others/Conway.java
index 4ae4d7418fb4..ab39890c9ece 100644
--- a/src/main/java/com/thealgorithms/others/Conway.java
+++ b/src/main/java/com/thealgorithms/others/Conway.java
@@ -4,7 +4,9 @@
 import java.util.Arrays;
 import java.util.List;
 
-public class Conway {
+public final class Conway {
+    private Conway() {
+    }
 
     /*
      * This class will generate the conway sequence also known as the look and say sequence.
diff --git a/src/main/java/com/thealgorithms/others/CountChar.java b/src/main/java/com/thealgorithms/others/CountChar.java
index 5a78c0c17412..99441b83993d 100644
--- a/src/main/java/com/thealgorithms/others/CountChar.java
+++ b/src/main/java/com/thealgorithms/others/CountChar.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.others;
 
-public class CountChar {
+public final class CountChar {
+    private CountChar() {
+    }
 
     /**
      * Count non space character in string
diff --git a/src/main/java/com/thealgorithms/others/Damm.java b/src/main/java/com/thealgorithms/others/Damm.java
index a32ae246a2ec..55a4c5b81a89 100644
--- a/src/main/java/com/thealgorithms/others/Damm.java
+++ b/src/main/java/com/thealgorithms/others/Damm.java
@@ -14,7 +14,9 @@
  * @see <a href="https://en.wikipedia.org/wiki/Damm_algorithm">Wiki. Damm
  * algorithm</a>
  */
-public class Damm {
+public final class Damm {
+    private Damm() {
+    }
 
     /**
      * Weakly totally anti-symmetric quasigroup of order 10. This table is not
diff --git a/src/main/java/com/thealgorithms/others/Dijkstra.java b/src/main/java/com/thealgorithms/others/Dijkstra.java
index 172e151f79a2..56fc32a96259 100644
--- a/src/main/java/com/thealgorithms/others/Dijkstra.java
+++ b/src/main/java/com/thealgorithms/others/Dijkstra.java
@@ -20,7 +20,9 @@
 import java.util.NavigableSet;
 import java.util.TreeSet;
 
-public class Dijkstra {
+public final class Dijkstra {
+    private Dijkstra() {
+    }
 
     private static final Graph.Edge[] GRAPH = {
         // Distance from node "a" to node "b" is 7.
diff --git a/src/main/java/com/thealgorithms/others/FibbonaciSeries.java b/src/main/java/com/thealgorithms/others/FibbonaciSeries.java
index 103e943743c7..bb1500e5cdc1 100644
--- a/src/main/java/com/thealgorithms/others/FibbonaciSeries.java
+++ b/src/main/java/com/thealgorithms/others/FibbonaciSeries.java
@@ -15,7 +15,9 @@
  * Problem Statement: print all Fibonacci numbers that are smaller than your
  * given input N
  */
-public class FibbonaciSeries {
+public final class FibbonaciSeries {
+    private FibbonaciSeries() {
+    }
 
     public static void main(String[] args) {
         // Get input from the user
diff --git a/src/main/java/com/thealgorithms/others/FloydTriangle.java b/src/main/java/com/thealgorithms/others/FloydTriangle.java
index d25ab303e3ed..9e8879838e38 100644
--- a/src/main/java/com/thealgorithms/others/FloydTriangle.java
+++ b/src/main/java/com/thealgorithms/others/FloydTriangle.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-class FloydTriangle {
+final class FloydTriangle {
+    private FloydTriangle() {
+    }
 
     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/others/GuassLegendre.java b/src/main/java/com/thealgorithms/others/GuassLegendre.java
index 8b15739a6d91..5d2d585d19f5 100644
--- a/src/main/java/com/thealgorithms/others/GuassLegendre.java
+++ b/src/main/java/com/thealgorithms/others/GuassLegendre.java
@@ -6,7 +6,9 @@
  *
  * @author AKS1996
  */
-public class GuassLegendre {
+public final class GuassLegendre {
+    private GuassLegendre() {
+    }
 
     public static void main(String[] args) {
         for (int i = 1; i <= 3; ++i) {
diff --git a/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java b/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java
index 57ff204c39b1..0ae1e451bc6a 100644
--- a/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java
+++ b/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java
@@ -5,7 +5,9 @@
 import java.util.Scanner;
 import java.util.Set;
 
-public class HappyNumbersSeq {
+public final class HappyNumbersSeq {
+    private HappyNumbersSeq() {
+    }
 
     private static final Set<Integer> CYCLE_NUMS = new HashSet<>(Arrays.asList(4, 16, 20, 37, 58, 145));
 
diff --git a/src/main/java/com/thealgorithms/others/Huffman.java b/src/main/java/com/thealgorithms/others/Huffman.java
index cc8c8d09864f..4fdee5d5e70e 100644
--- a/src/main/java/com/thealgorithms/others/Huffman.java
+++ b/src/main/java/com/thealgorithms/others/Huffman.java
@@ -26,7 +26,9 @@ public int compare(HuffmanNode x, HuffmanNode y) {
     }
 }
 
-public class Huffman {
+public final class Huffman {
+    private Huffman() {
+    }
 
     // recursive function to print the
     // huffman-code through the tree traversal.
diff --git a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
index d394ae102130..e4a9cbba45de 100644
--- a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
+++ b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-public class InsertDeleteInArray {
+public final class InsertDeleteInArray {
+    private InsertDeleteInArray() {
+    }
 
     public static void main(String[] args) {
         try (Scanner s = new Scanner(System.in)) {
diff --git a/src/main/java/com/thealgorithms/others/KMP.java b/src/main/java/com/thealgorithms/others/KMP.java
index 7fb5645a2726..1caa6b63cddc 100644
--- a/src/main/java/com/thealgorithms/others/KMP.java
+++ b/src/main/java/com/thealgorithms/others/KMP.java
@@ -4,7 +4,9 @@
  * Implementation of Knuth–Morris–Pratt algorithm Usage: see the main function
  * for an example
  */
-public class KMP {
+public final class KMP {
+    private KMP() {
+    }
 
     // a working example
 
diff --git a/src/main/java/com/thealgorithms/others/KochSnowflake.java b/src/main/java/com/thealgorithms/others/KochSnowflake.java
index a87eedebee73..1762d6cfac0f 100644
--- a/src/main/java/com/thealgorithms/others/KochSnowflake.java
+++ b/src/main/java/com/thealgorithms/others/KochSnowflake.java
@@ -24,7 +24,9 @@
  * https://natureofcode.com/book/chapter-8-fractals/
  * #84-the-koch-curve-and-the-arraylist-technique ).
  */
-public class KochSnowflake {
+public final class KochSnowflake {
+    private KochSnowflake() {
+    }
 
     public static void main(String[] args) {
         // Test Iterate-method
diff --git a/src/main/java/com/thealgorithms/others/Krishnamurthy.java b/src/main/java/com/thealgorithms/others/Krishnamurthy.java
index 1f7cd121933f..465d7e9c4265 100644
--- a/src/main/java/com/thealgorithms/others/Krishnamurthy.java
+++ b/src/main/java/com/thealgorithms/others/Krishnamurthy.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-class Krishnamurthy {
+final class Krishnamurthy {
+    private Krishnamurthy() {
+    }
 
     static int fact(int n) {
         int i, p = 1;
diff --git a/src/main/java/com/thealgorithms/others/LineSweep.java b/src/main/java/com/thealgorithms/others/LineSweep.java
index 9aa0f6faa8e6..cb7f5214b0dc 100644
--- a/src/main/java/com/thealgorithms/others/LineSweep.java
+++ b/src/main/java/com/thealgorithms/others/LineSweep.java
@@ -11,7 +11,9 @@
  * https://en.wikipedia.org/wiki/Sweep_line_algorithm
  * https://en.wikipedia.org/wiki/De_Morgan%27s_laws>
  */
-public class LineSweep {
+public final class LineSweep {
+    private LineSweep() {
+    }
 
     /**
      * Find Maximum end point
diff --git a/src/main/java/com/thealgorithms/others/Luhn.java b/src/main/java/com/thealgorithms/others/Luhn.java
index fd5433ca7b65..600128a7725b 100644
--- a/src/main/java/com/thealgorithms/others/Luhn.java
+++ b/src/main/java/com/thealgorithms/others/Luhn.java
@@ -38,7 +38,9 @@
  *
  * @see <a href="https://en.wikipedia.org/wiki/Luhn_algorithm">Wiki</a>
  */
-public class Luhn {
+public final class Luhn {
+    private Luhn() {
+    }
 
     /**
      * Check input digits array by Luhn algorithm. Initial array doesn't change
diff --git a/src/main/java/com/thealgorithms/others/Mandelbrot.java b/src/main/java/com/thealgorithms/others/Mandelbrot.java
index 15618495646f..6d7588090ba8 100644
--- a/src/main/java/com/thealgorithms/others/Mandelbrot.java
+++ b/src/main/java/com/thealgorithms/others/Mandelbrot.java
@@ -23,7 +23,9 @@
  * also https://en.wikipedia.org/wiki/Plotting_algorithms_for_the_Mandelbrot_set
  * )
  */
-public class Mandelbrot {
+public final class Mandelbrot {
+    private Mandelbrot() {
+    }
 
     public static void main(String[] args) {
         // Test black and white
diff --git a/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java b/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
index 3056f14dacfc..0bafc435aa75 100644
--- a/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
+++ b/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
@@ -8,7 +8,9 @@
 * items from the end of the window are removed from consideration while new items from the stream take their place.
 * @author Swarga-codes (https://github.com/Swarga-codes)
 */
-public class MaximumSumOfDistinctSubarraysWithLengthK {
+public final class MaximumSumOfDistinctSubarraysWithLengthK {
+    private MaximumSumOfDistinctSubarraysWithLengthK() {
+    }
     /*
      * Returns the maximum sum of subarray of size K consisting of distinct
      * elements.
diff --git a/src/main/java/com/thealgorithms/others/PasswordGen.java b/src/main/java/com/thealgorithms/others/PasswordGen.java
index c079d1cbebd2..f982848a5c1a 100644
--- a/src/main/java/com/thealgorithms/others/PasswordGen.java
+++ b/src/main/java/com/thealgorithms/others/PasswordGen.java
@@ -11,11 +11,8 @@
  * @author AKS1996
  * @date 2017.10.25
  */
-class PasswordGen {
-
-    public static void main(String[] args) {
-        String password = generatePassword(8, 16);
-        System.out.print("Password: " + password);
+final class PasswordGen {
+    private PasswordGen() {
     }
 
     static String generatePassword(int min_length, int max_length) {
diff --git a/src/main/java/com/thealgorithms/others/PerlinNoise.java b/src/main/java/com/thealgorithms/others/PerlinNoise.java
index 2f774e16ba90..e6551ed6b9ee 100644
--- a/src/main/java/com/thealgorithms/others/PerlinNoise.java
+++ b/src/main/java/com/thealgorithms/others/PerlinNoise.java
@@ -7,7 +7,9 @@
  * For detailed info and implementation see: <a
  * href="http://devmag.org.za/2009/04/25/perlin-noise/">Perlin-Noise</a>
  */
-public class PerlinNoise {
+public final class PerlinNoise {
+    private PerlinNoise() {
+    }
 
     /**
      * @param width width of noise array
diff --git a/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java b/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java
index 2499d9373354..259e108a354d 100644
--- a/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java
+++ b/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java
@@ -112,7 +112,9 @@ public boolean isOutStackEmpty() {
  *
  * @author sahilb2 (https://www.github.com/sahilb2)
  */
-public class QueueUsingTwoStacks {
+public final class QueueUsingTwoStacks {
+    private QueueUsingTwoStacks() {
+    }
 
     /**
      * Main method
diff --git a/src/main/java/com/thealgorithms/others/RabinKarp.java b/src/main/java/com/thealgorithms/others/RabinKarp.java
index 6358ce4aaaba..8188a1a702d0 100644
--- a/src/main/java/com/thealgorithms/others/RabinKarp.java
+++ b/src/main/java/com/thealgorithms/others/RabinKarp.java
@@ -7,7 +7,9 @@
 
 // An implementation of Rabin-Karp string matching algorithm
 // Program will simply end if there is no match
-public class RabinKarp {
+public final class RabinKarp {
+    private RabinKarp() {
+    }
 
     public static Scanner SCANNER = null;
     public static final int ALPHABET_SIZE = 256;
diff --git a/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java b/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java
index 5e4662b0b052..695a10648b6c 100644
--- a/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java
+++ b/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java
@@ -6,7 +6,9 @@
 /**
  * @author Varun Upadhyay (https://github.com/varunu28)
  */
-public class RemoveDuplicateFromString {
+public final class RemoveDuplicateFromString {
+    private RemoveDuplicateFromString() {
+    }
 
     public static void main(String[] args) throws Exception {
         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
diff --git a/src/main/java/com/thealgorithms/others/ReturnSubsequence.java b/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
index 0d8cbea0d3b3..cf2f091a102f 100644
--- a/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
+++ b/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-public class ReturnSubsequence {
+public final class ReturnSubsequence {
+    private ReturnSubsequence() {
+    }
 
     public static void main(String[] args) {
         System.out.println("Enter String: ");
diff --git a/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java b/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
index 7c0fe0b2c6f6..2c26f8eae4dc 100644
--- a/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
+++ b/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
@@ -3,7 +3,9 @@
 /* Program to reverse a Stack using Recursion*/
 import java.util.Stack;
 
-public class ReverseStackUsingRecursion {
+public final class ReverseStackUsingRecursion {
+    private ReverseStackUsingRecursion() {
+    }
 
     // Stack
     private static Stack<Integer> stack = new Stack<>();
diff --git a/src/main/java/com/thealgorithms/others/RootPrecision.java b/src/main/java/com/thealgorithms/others/RootPrecision.java
index e22db1b99931..a804f8f69db4 100644
--- a/src/main/java/com/thealgorithms/others/RootPrecision.java
+++ b/src/main/java/com/thealgorithms/others/RootPrecision.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-public class RootPrecision {
+public final class RootPrecision {
+    private RootPrecision() {
+    }
 
     public static void main(String[] args) {
         // take input
diff --git a/src/main/java/com/thealgorithms/others/RotateMatriceBy90Degree.java b/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
similarity index 92%
rename from src/main/java/com/thealgorithms/others/RotateMatriceBy90Degree.java
rename to src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
index c9ebc45483aa..081b0d16dce8 100644
--- a/src/main/java/com/thealgorithms/others/RotateMatriceBy90Degree.java
+++ b/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
@@ -6,7 +6,9 @@
  */
 import java.util.Scanner;
 
-class Rotate_by_90_degree {
+class Rotate_by_90_degrees {
+    private Rotate_by_90_degrees() {
+    }
 
     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
@@ -41,7 +43,9 @@ static void printMatrix(int[][] arr) {
 /**
  * Class containing the algo to roate matrix by 90 degree
  */
-class Rotate {
+final class Rotate {
+    private Rotate() {
+    }
 
     static void rotate(int[][] a) {
         int n = a.length;
diff --git a/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java b/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
index fa3869bc5d2e..15148de176b1 100644
--- a/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
+++ b/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
@@ -6,7 +6,9 @@
 import java.util.Scanner;
 
 // An implementaion of string matching using finite automata
-public class StringMatchFiniteAutomata {
+public final class StringMatchFiniteAutomata {
+    private StringMatchFiniteAutomata() {
+    }
 
     public static final int CHARS = 256;
     public static int[][] FA;
diff --git a/src/main/java/com/thealgorithms/others/Sudoku.java b/src/main/java/com/thealgorithms/others/Sudoku.java
index d2bc1d5c7add..d27a1648b743 100644
--- a/src/main/java/com/thealgorithms/others/Sudoku.java
+++ b/src/main/java/com/thealgorithms/others/Sudoku.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.others;
 
-class Sudoku {
+final class Sudoku {
+    private Sudoku() {
+    }
 
     public static boolean isSafe(int[][] board, int row, int col, int num) {
         // Row has the unique (row-clash)
diff --git a/src/main/java/com/thealgorithms/others/TopKWords.java b/src/main/java/com/thealgorithms/others/TopKWords.java
index bb84d3f767e3..4e30bbb4bdaa 100644
--- a/src/main/java/com/thealgorithms/others/TopKWords.java
+++ b/src/main/java/com/thealgorithms/others/TopKWords.java
@@ -11,7 +11,9 @@
 
 /* display the most frequent K words in the file and the times it appear
 in the file – shown in order (ignore case and periods) */
-public class TopKWords {
+public final class TopKWords {
+    private TopKWords() {
+    }
 
     static class CountWords {
 
diff --git a/src/main/java/com/thealgorithms/others/TowerOfHanoi.java b/src/main/java/com/thealgorithms/others/TowerOfHanoi.java
index c0fb4d75f84d..8969c002cb22 100644
--- a/src/main/java/com/thealgorithms/others/TowerOfHanoi.java
+++ b/src/main/java/com/thealgorithms/others/TowerOfHanoi.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-class TowerOfHanoi {
+final class TowerOfHanoi {
+    private TowerOfHanoi() {
+    }
 
     public static void shift(int n, String startPole, String intermediatePole, String endPole) {
         // if n becomes zero the program returns thus ending the loop.
diff --git a/src/main/java/com/thealgorithms/others/TwoPointers.java b/src/main/java/com/thealgorithms/others/TwoPointers.java
index de44354a6602..01391ec72e78 100644
--- a/src/main/java/com/thealgorithms/others/TwoPointers.java
+++ b/src/main/java/com/thealgorithms/others/TwoPointers.java
@@ -9,7 +9,9 @@
  * <p>
  * link: https://www.geeksforgeeks.org/two-pointers-technique/
  */
-class TwoPointers {
+final class TwoPointers {
+    private TwoPointers() {
+    }
 
     /**
      * Given a sorted array arr (sorted in ascending order). Find if there
diff --git a/src/main/java/com/thealgorithms/others/Verhoeff.java b/src/main/java/com/thealgorithms/others/Verhoeff.java
index 2144f373e2a4..9088612aaa43 100644
--- a/src/main/java/com/thealgorithms/others/Verhoeff.java
+++ b/src/main/java/com/thealgorithms/others/Verhoeff.java
@@ -23,7 +23,9 @@
  * @see <a href="https://en.wikipedia.org/wiki/Verhoeff_algorithm">Wiki.
  * Verhoeff algorithm</a>
  */
-public class Verhoeff {
+public final class Verhoeff {
+    private Verhoeff() {
+    }
 
     /**
      * Table {@code d}. Based on multiplication in the dihedral group D5 and is
diff --git a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
index f4ab56636266..9bcd5df81056 100644
--- a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
@@ -24,7 +24,9 @@ class Process {
     }
 }
 
-public class PreemptivePriorityScheduling {
+public final class PreemptivePriorityScheduling {
+    private PreemptivePriorityScheduling() {
+    }
     public static List<String> preemptivePriorityScheduling(List<Process> processes) {
         List<String> ganttChart = new ArrayList<>();
         PriorityQueue<Process> readyQueue = new PriorityQueue<>(Comparator.comparingInt(p -> - p.priority));
diff --git a/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java b/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
index e4c0cf9d06a2..164f906a38b8 100644
--- a/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
+++ b/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
@@ -8,7 +8,9 @@
 above it will also be smaller than the target), else that element is greater than the target, then
 the rows below it are ignored.
  */
-public class BinarySearch2dArray {
+public final class BinarySearch2dArray {
+    private BinarySearch2dArray() {
+    }
 
     static int[] BinarySearch(int[][] arr, int target) {
         int rowCount = arr.length, colCount = arr[0].length;
diff --git a/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java b/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java
index 350a3a6fede1..8e601f9873b3 100644
--- a/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java
+++ b/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java
@@ -25,7 +25,9 @@ at the rotated array, to identify the minimum element (say a[i]), we observe tha
     1. [1,2,3,4] Number of rotations: 0 or 4(Both valid)
     2. [15,17,2,3,5] Number of rotations: 3
  */
-class HowManyTimesRotated {
+final class HowManyTimesRotated {
+    private HowManyTimesRotated() {
+    }
 
     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/searches/LinearSearchThread.java b/src/main/java/com/thealgorithms/searches/LinearSearchThread.java
index 6e9d73af6b1f..d3d04e4f79cc 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearchThread.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearchThread.java
@@ -2,7 +2,9 @@
 
 import java.util.Scanner;
 
-public class LinearSearchThread {
+public final class LinearSearchThread {
+    private LinearSearchThread() {
+    }
 
     public static void main(String[] args) {
         int[] list = new int[200];
diff --git a/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java b/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
index 8ae304f6103f..bb593503ff61 100644
--- a/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
@@ -1,46 +1,48 @@
-package com.thealgorithms.searches;
-
-// URL: https://www.geeksforgeeks.org/order-agnostic-binary-search/
-
-/* Order Agnostic Binary Search is an algorithm where we do not know whether the given
-   sorted array is ascending or descending order.
-   We declare a boolean variable to find whether the array is ascending order.
-   In the while loop, we use the two pointer method (start and end) to get the middle element.
-   if the middle element is equal to our target element, then that is the answer.
-   If not, then we check if the array is ascending or descending order.
-   Depending upon the condition, respective statements will be executed and we will get our answer.
- */
-
-public class OrderAgnosticBinarySearch {
-
-    static int BinSearchAlgo(int[] arr, int start, int end, int target) {
-
-        // Checking whether the given array is ascending order
-        boolean AscOrd = arr[start] < arr[end];
-
-        while (start <= end) {
-            int middle = start + (end - start) / 2;
-
-            // Check if the desired element is present at the middle position
-            if (arr[middle] == target) return middle; // returns the index of the middle element
-
-            // Ascending order
-            if (AscOrd) {
-                if (arr[middle] < target)
-                    start = middle + 1;
-                else
-                    end = middle - 1;
-            }
-
-            // Descending order
-            else {
-                if (arr[middle] > target)
-                    start = middle + 1;
-                else
-                    end = middle - 1;
-            }
-        }
-        // Element is not present
-        return -1;
-    }
-}
+package com.thealgorithms.searches;
+
+// URL: https://www.geeksforgeeks.org/order-agnostic-binary-search/
+
+/* Order Agnostic Binary Search is an algorithm where we do not know whether the given
+   sorted array is ascending or descending order.
+   We declare a boolean variable to find whether the array is ascending order.
+   In the while loop, we use the two pointer method (start and end) to get the middle element.
+   if the middle element is equal to our target element, then that is the answer.
+   If not, then we check if the array is ascending or descending order.
+   Depending upon the condition, respective statements will be executed and we will get our answer.
+ */
+
+public final class OrderAgnosticBinarySearch {
+    private OrderAgnosticBinarySearch() {
+    }
+
+    static int BinSearchAlgo(int[] arr, int start, int end, int target) {
+
+        // Checking whether the given array is ascending order
+        boolean AscOrd = arr[start] < arr[end];
+
+        while (start <= end) {
+            int middle = start + (end - start) / 2;
+
+            // Check if the desired element is present at the middle position
+            if (arr[middle] == target) return middle; // returns the index of the middle element
+
+            // Ascending order
+            if (AscOrd) {
+                if (arr[middle] < target)
+                    start = middle + 1;
+                else
+                    end = middle - 1;
+            }
+
+            // Descending order
+            else {
+                if (arr[middle] > target)
+                    start = middle + 1;
+                else
+                    end = middle - 1;
+            }
+        }
+        // Element is not present
+        return -1;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/searches/QuickSelect.java b/src/main/java/com/thealgorithms/searches/QuickSelect.java
index f5ed7f71c9ed..97eab4bb4046 100644
--- a/src/main/java/com/thealgorithms/searches/QuickSelect.java
+++ b/src/main/java/com/thealgorithms/searches/QuickSelect.java
@@ -10,6 +10,8 @@
  * <a href="https://en.wikipedia.org/wiki/Median_of_medians">here</a>.
  */
 public final class QuickSelect {
+    private QuickSelect() {
+    }
 
     /**
      * Selects the {@code n}-th largest element of {@code list}, i.e. the element that would
diff --git a/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java b/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java
index 4e5939d6b2b8..6ec1aa5ceb5e 100644
--- a/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java
+++ b/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java
@@ -16,7 +16,9 @@
  *
  * @author Nishita Aggarwal
  */
-public class SaddlebackSearch {
+public final class SaddlebackSearch {
+    private SaddlebackSearch() {
+    }
 
     /**
      * This method performs Saddleback Search
diff --git a/src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java b/src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java
index afd5c194f7c4..c00bfc9da6f5 100644
--- a/src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java
@@ -14,7 +14,9 @@
  *
  * @author sahil
  */
-public class SquareRootBinarySearch {
+public final class SquareRootBinarySearch {
+    private SquareRootBinarySearch() {
+    }
 
     /**
      * This is the driver method.
diff --git a/src/main/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearch.java b/src/main/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearch.java
index 817d9b355450..acb9fb5cb3cd 100644
--- a/src/main/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearch.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.searches;
-public class sortOrderAgnosticBinarySearch {
+public final class sortOrderAgnosticBinarySearch {
+    private sortOrderAgnosticBinarySearch() {
+    }
     public static int find(int[] arr, int key) {
         int start = 0;
         int end = arr.length - 1;
diff --git a/src/main/java/com/thealgorithms/sorts/BucketSort.java b/src/main/java/com/thealgorithms/sorts/BucketSort.java
index 184e36f04db6..2a48cca0f433 100644
--- a/src/main/java/com/thealgorithms/sorts/BucketSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BucketSort.java
@@ -8,7 +8,9 @@
 /**
  * Wikipedia: https://en.wikipedia.org/wiki/Bucket_sort
  */
-public class BucketSort {
+public final class BucketSort {
+    private BucketSort() {
+    }
 
     public static void main(String[] args) {
         int[] arr = new int[10];
diff --git a/src/main/java/com/thealgorithms/sorts/DNFSort.java b/src/main/java/com/thealgorithms/sorts/DNFSort.java
index 7f50deca47aa..7074e2cbe63a 100644
--- a/src/main/java/com/thealgorithms/sorts/DNFSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DNFSort.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.sorts;
 
-public class DNFSort {
+public final class DNFSort {
+    private DNFSort() {
+    }
 
     // Sort the input array, the array is assumed to
     // have values in {0, 1, 2}
diff --git a/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java b/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
index f235d2105b72..803085f9f582 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
@@ -6,7 +6,9 @@
 /*This code implements the mergeSort algorithm without extra space
 For understanding about mergesort visit :https://www.geeksforgeeks.org/merge-sort/
  */
-public class MergeSortNoExtraSpace {
+public final class MergeSortNoExtraSpace {
+    private MergeSortNoExtraSpace() {
+    }
 
     public static void call_merge_sort(int[] a, int n) {
         int maxele = Arrays.stream(a).max().getAsInt() + 1;
diff --git a/src/main/java/com/thealgorithms/sorts/OddEvenSort.java b/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
index b5213792d12d..fb6e4d2649cb 100644
--- a/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
+++ b/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
@@ -3,7 +3,9 @@
 import java.util.Random;
 
 // https://en.wikipedia.org/wiki/Odd%E2%80%93even_sort
-public class OddEvenSort {
+public final class OddEvenSort {
+    private OddEvenSort() {
+    }
 
     public static void main(String[] args) {
         int[] arr = new int[100];
diff --git a/src/main/java/com/thealgorithms/sorts/RadixSort.java b/src/main/java/com/thealgorithms/sorts/RadixSort.java
index d2090bf86646..847b94036ca9 100644
--- a/src/main/java/com/thealgorithms/sorts/RadixSort.java
+++ b/src/main/java/com/thealgorithms/sorts/RadixSort.java
@@ -2,7 +2,9 @@
 
 import java.util.Arrays;
 
-class RadixSort {
+final class RadixSort {
+    private RadixSort() {
+    }
 
     private static int getMax(int[] arr, int n) {
         int mx = arr[0];
diff --git a/src/main/java/com/thealgorithms/sorts/SortUtils.java b/src/main/java/com/thealgorithms/sorts/SortUtils.java
index 9e114b2084fc..fda1975189ec 100644
--- a/src/main/java/com/thealgorithms/sorts/SortUtils.java
+++ b/src/main/java/com/thealgorithms/sorts/SortUtils.java
@@ -5,6 +5,8 @@
 import java.util.stream.Collectors;
 
 final class SortUtils {
+    private SortUtils() {
+    }
 
     /**
      * Swaps two elements at the given positions in an array.
diff --git a/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java b/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java
index d39d40e79a7d..b048d0245b64 100644
--- a/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java
+++ b/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java
@@ -2,7 +2,9 @@
 
 import java.util.Random;
 
-public class SortUtilsRandomGenerator {
+public final class SortUtilsRandomGenerator {
+    private SortUtilsRandomGenerator() {
+    }
 
     private static final Random RANDOM;
     private static final long SEED;
diff --git a/src/main/java/com/thealgorithms/sorts/StrandSort.java b/src/main/java/com/thealgorithms/sorts/StrandSort.java
index 2d8411faca4f..7e2251d70640 100644
--- a/src/main/java/com/thealgorithms/sorts/StrandSort.java
+++ b/src/main/java/com/thealgorithms/sorts/StrandSort.java
@@ -3,7 +3,9 @@
 import java.util.Iterator;
 import java.util.LinkedList;
 
-public class StrandSort {
+public final class StrandSort {
+    private StrandSort() {
+    }
 
     // note: the input list is destroyed
     public static <E extends Comparable<? super E>> LinkedList<E> strandSort(LinkedList<E> list) {
diff --git a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
index ac375e2a54f0..ce664b0197fc 100644
--- a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
@@ -16,7 +16,9 @@
  * @author Jonathan Taylor (https://github.com/Jtmonument)
  * Based on Introduction to Algorithms 3rd Edition
  */
-public class TopologicalSort {
+public final class TopologicalSort {
+    private TopologicalSort() {
+    }
 
     /*
      * Enum to represent the colors for the depth first search
diff --git a/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java b/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java
index a73697a7df21..a8f5254b22c5 100644
--- a/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java
+++ b/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java
@@ -16,7 +16,9 @@
  * @author <a href="https://github.com/khalil2535">khalil2535<a>
  * @author shellhub
  */
-class BalancedBrackets {
+final class BalancedBrackets {
+    private BalancedBrackets() {
+    }
 
     /**
      * Check if {@code leftBracket} and {@code rightBracket} is paired or not
diff --git a/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java b/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java
index 0a206a8ba1e9..41d1c6408ee5 100644
--- a/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java
+++ b/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java
@@ -2,7 +2,9 @@
 
 import java.util.Stack;
 
-public class DecimalToAnyUsingStack {
+public final class DecimalToAnyUsingStack {
+    private DecimalToAnyUsingStack() {
+    }
 
     public static void main(String[] args) {
         assert convert(0, 2).equals("0");
diff --git a/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java b/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
index f78a24112d43..2fb03de77de5 100644
--- a/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
+++ b/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
@@ -11,7 +11,9 @@
 import java.util.Scanner;
 import java.util.Stack;
 
-public class DuplicateBrackets {
+public final class DuplicateBrackets {
+    private DuplicateBrackets() {
+    }
 
     public static boolean check(String str) {
         Stack<Character> st = new Stack<>();
diff --git a/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java b/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java
index 2cafdc940650..e3519978c6e5 100644
--- a/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java
+++ b/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java
@@ -2,7 +2,9 @@
 
 import java.util.Stack;
 
-public class InfixToPostfix {
+public final class InfixToPostfix {
+    private InfixToPostfix() {
+    }
 
     public static void main(String[] args) throws Exception {
         assert "32+".equals(infix2PostFix("3+2"));
diff --git a/src/main/java/com/thealgorithms/stacks/LargestRectangle.java b/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
index 63f1d0b4f30d..b3004a284a15 100644
--- a/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
+++ b/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
@@ -7,7 +7,9 @@
  * @author mohd rameez github.com/rameez471
  */
 
-public class LargestRectangle {
+public final class LargestRectangle {
+    private LargestRectangle() {
+    }
 
     public static String largestRectanglehistogram(int[] heights) {
         int n = heights.length, maxArea = 0;
diff --git a/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java b/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java
index 5eb895d945e5..d76122b16632 100644
--- a/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java
+++ b/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java
@@ -27,7 +27,9 @@
  *
  * @author sahil
  */
-public class MaximumMinimumWindow {
+public final class MaximumMinimumWindow {
+    private MaximumMinimumWindow() {
+    }
 
     /**
      * This function contains the logic of finding maximum of minimum for every
diff --git a/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java b/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java
index d681e41fbfc3..f7cbea714eb0 100644
--- a/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java
+++ b/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java
@@ -41,7 +41,9 @@ Next greater element between (6 to n) is -1
    -1.
  */
 
-public class NextGreaterElement {
+public final class NextGreaterElement {
+    private NextGreaterElement() {
+    }
 
     public static int[] findNextGreaterElements(int[] array) {
         if (array == null) {
diff --git a/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java b/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java
index 84263d986508..4d37da0e7c31 100644
--- a/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java
+++ b/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java
@@ -37,7 +37,9 @@ Next smaller element between (0 , 5) is 6
    answer is -1
  */
 
-public class NextSmallerElement {
+public final class NextSmallerElement {
+    private NextSmallerElement() {
+    }
 
     public static int[] findNextSmallerElements(int[] array) {
         // base case
diff --git a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
index 0c674ec02a1e..6a0453d887c2 100644
--- a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
+++ b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
@@ -16,7 +16,9 @@
  *
  */
 
-public class PostfixToInfix {
+public final class PostfixToInfix {
+    private PostfixToInfix() {
+    }
 
     public static boolean isOperator(char token) {
         switch (token) {
diff --git a/src/main/java/com/thealgorithms/strings/Alphabetical.java b/src/main/java/com/thealgorithms/strings/Alphabetical.java
index fde17c883917..de07dde2d510 100644
--- a/src/main/java/com/thealgorithms/strings/Alphabetical.java
+++ b/src/main/java/com/thealgorithms/strings/Alphabetical.java
@@ -5,7 +5,9 @@
  * based on the position of the characters in the conventional ordering of an
  * alphabet. Wikipedia: https://en.wikipedia.org/wiki/Alphabetical_order
  */
-class Alphabetical {
+final class Alphabetical {
+    private Alphabetical() {
+    }
 
     public static void main(String[] args) {
         assert !isAlphabetical("123abc");
diff --git a/src/main/java/com/thealgorithms/strings/CharactersSame.java b/src/main/java/com/thealgorithms/strings/CharactersSame.java
index e0243fa8edef..78ccbbea4898 100644
--- a/src/main/java/com/thealgorithms/strings/CharactersSame.java
+++ b/src/main/java/com/thealgorithms/strings/CharactersSame.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.strings;
 
-public class CharactersSame {
+public final class CharactersSame {
+    private CharactersSame() {
+    }
 
     /**
      * Driver Code
diff --git a/src/main/java/com/thealgorithms/strings/CheckAnagrams.java b/src/main/java/com/thealgorithms/strings/CheckAnagrams.java
index a20e8b4ad418..7bf7cd9a7c66 100644
--- a/src/main/java/com/thealgorithms/strings/CheckAnagrams.java
+++ b/src/main/java/com/thealgorithms/strings/CheckAnagrams.java
@@ -7,7 +7,9 @@
  * Two strings are anagrams if they are made of the same letters arranged
  * differently (ignoring the case).
  */
-public class CheckAnagrams {
+public final class CheckAnagrams {
+    private CheckAnagrams() {
+    }
     /**
      * Check if two strings are anagrams or not
      *
diff --git a/src/main/java/com/thealgorithms/strings/CheckVowels.java b/src/main/java/com/thealgorithms/strings/CheckVowels.java
index 7b4fca3d54ce..44965cc9282c 100644
--- a/src/main/java/com/thealgorithms/strings/CheckVowels.java
+++ b/src/main/java/com/thealgorithms/strings/CheckVowels.java
@@ -9,7 +9,9 @@
  * on the position of the characters in the conventional ordering of an
  * alphabet. Wikipedia: https://en.wikipedia.org/wiki/Alphabetical_order
  */
-public class CheckVowels {
+public final class CheckVowels {
+    private CheckVowels() {
+    }
 
     private static final Set<Character> VOWELS = new HashSet<>(Arrays.asList('a', 'e', 'i', 'o', 'u'));
 
diff --git a/src/main/java/com/thealgorithms/strings/HammingDistance.java b/src/main/java/com/thealgorithms/strings/HammingDistance.java
index bfa3114b1c03..95c523ccd411 100644
--- a/src/main/java/com/thealgorithms/strings/HammingDistance.java
+++ b/src/main/java/com/thealgorithms/strings/HammingDistance.java
@@ -4,7 +4,9 @@
 is the number of positions at which the corresponding symbols are different.
 https://en.wikipedia.org/wiki/Hamming_distance
 */
-public class HammingDistance {
+public final class HammingDistance {
+    private HammingDistance() {
+    }
 
     /**
      * calculate the hamming distance between two strings of equal length
diff --git a/src/main/java/com/thealgorithms/strings/HorspoolSearch.java b/src/main/java/com/thealgorithms/strings/HorspoolSearch.java
index 99ba2399c42f..d9187cbf66c4 100644
--- a/src/main/java/com/thealgorithms/strings/HorspoolSearch.java
+++ b/src/main/java/com/thealgorithms/strings/HorspoolSearch.java
@@ -44,7 +44,9 @@
  * recommend checking out the wikipedia page and professor Anany Levitin's book:
  * Introduction To The Design And Analysis Of Algorithms.
  */
-public class HorspoolSearch {
+public final class HorspoolSearch {
+    private HorspoolSearch() {
+    }
 
     private static HashMap<Character, Integer> shiftValues; // bad symbol table
     private static Integer patternLength;
diff --git a/src/main/java/com/thealgorithms/strings/Isomorphic.java b/src/main/java/com/thealgorithms/strings/Isomorphic.java
index d7f436b0de75..088addc6ea45 100644
--- a/src/main/java/com/thealgorithms/strings/Isomorphic.java
+++ b/src/main/java/com/thealgorithms/strings/Isomorphic.java
@@ -5,7 +5,9 @@
 import java.util.Map;
 import java.util.Set;
 
-public class Isomorphic {
+public final class Isomorphic {
+    private Isomorphic() {
+    }
 
     public static boolean checkStrings(String s, String t) {
         if (s.length() != t.length()) {
diff --git a/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java b/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java
index 963684e4aff3..2e3ee25fb6ea 100644
--- a/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java
+++ b/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java
@@ -4,7 +4,9 @@
 import java.util.Collections;
 import java.util.List;
 
-public class LetterCombinationsOfPhoneNumber {
+public final class LetterCombinationsOfPhoneNumber {
+    private LetterCombinationsOfPhoneNumber() {
+    }
 
     static Character[][] numberToCharMap;
 
diff --git a/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java b/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java
index a74a10aa05c0..fa9171133a15 100644
--- a/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java
+++ b/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java
@@ -3,7 +3,9 @@
 // Longest Palindromic Substring
 import java.util.Scanner;
 
-class LongestPalindromicSubstring {
+final class LongestPalindromicSubstring {
+    private LongestPalindromicSubstring() {
+    }
 
     public static void main(String[] args) {
         Solution s = new Solution();
diff --git a/src/main/java/com/thealgorithms/strings/Lower.java b/src/main/java/com/thealgorithms/strings/Lower.java
index ef3902b15df3..e20cc5f0f2f7 100644
--- a/src/main/java/com/thealgorithms/strings/Lower.java
+++ b/src/main/java/com/thealgorithms/strings/Lower.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.strings;
 
-public class Lower {
+public final class Lower {
+    private Lower() {
+    }
 
     /**
      * Driver Code
diff --git a/src/main/java/com/thealgorithms/strings/MyAtoi.java b/src/main/java/com/thealgorithms/strings/MyAtoi.java
index a8669273a3cd..119d75e4d828 100644
--- a/src/main/java/com/thealgorithms/strings/MyAtoi.java
+++ b/src/main/java/com/thealgorithms/strings/MyAtoi.java
@@ -3,7 +3,9 @@
 
 package com.thealgorithms.strings;
 
-public class MyAtoi {
+public final class MyAtoi {
+    private MyAtoi() {
+    }
     public static int myAtoi(String s) {
         s = s.trim();
         char[] char_1 = s.toCharArray();
diff --git a/src/main/java/com/thealgorithms/strings/Palindrome.java b/src/main/java/com/thealgorithms/strings/Palindrome.java
index c0cab91bb7c6..3567a371d70e 100644
--- a/src/main/java/com/thealgorithms/strings/Palindrome.java
+++ b/src/main/java/com/thealgorithms/strings/Palindrome.java
@@ -3,7 +3,9 @@
 /**
  * Wikipedia: https://en.wikipedia.org/wiki/Palindrome
  */
-class Palindrome {
+final class Palindrome {
+    private Palindrome() {
+    }
 
     /**
      * Check if a string is palindrome string or not using String Builder
diff --git a/src/main/java/com/thealgorithms/strings/Pangram.java b/src/main/java/com/thealgorithms/strings/Pangram.java
index d2c9f3e5baa0..e0989ce86715 100644
--- a/src/main/java/com/thealgorithms/strings/Pangram.java
+++ b/src/main/java/com/thealgorithms/strings/Pangram.java
@@ -5,7 +5,9 @@
 /**
  * Wikipedia: https://en.wikipedia.org/wiki/Pangram
  */
-public class Pangram {
+public final class Pangram {
+    private Pangram() {
+    }
 
     /**
      * Test code
diff --git a/src/main/java/com/thealgorithms/strings/PermuteString.java b/src/main/java/com/thealgorithms/strings/PermuteString.java
index d4abb67440b4..f263292eb7bd 100644
--- a/src/main/java/com/thealgorithms/strings/PermuteString.java
+++ b/src/main/java/com/thealgorithms/strings/PermuteString.java
@@ -11,7 +11,9 @@
 again, and we backtrack to the previous position and swap B with C. So, now we got ABC and ACB.
 >>Repeat these steps for BAC and CBA, to get all the permutations.
  */
-public class PermuteString {
+public final class PermuteString {
+    private PermuteString() {
+    }
 
     // Function for swapping the characters at position I with character at position j
     public static String swapString(String a, int i, int j) {
diff --git a/src/main/java/com/thealgorithms/strings/ReverseString.java b/src/main/java/com/thealgorithms/strings/ReverseString.java
index c5f54f745470..b47a77e9226c 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseString.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseString.java
@@ -3,7 +3,9 @@
 /**
  * Reverse String using different version
  */
-public class ReverseString {
+public final class ReverseString {
+    private ReverseString() {
+    }
 
     public static void main(String[] args) {
         assert reverse("abc123").equals("321cba");
diff --git a/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java b/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java
index 0cd2a971b225..e180f6c3991b 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java
@@ -4,7 +4,9 @@
  * Reverse String using Recursion
  */
 
-public class ReverseStringRecursive {
+public final class ReverseStringRecursive {
+    private ReverseStringRecursive() {
+    }
     /**
      * @param str string to be reversed
      * @return reversed string
diff --git a/src/main/java/com/thealgorithms/strings/Rotation.java b/src/main/java/com/thealgorithms/strings/Rotation.java
index c82ae5c32758..e1352f1197b1 100644
--- a/src/main/java/com/thealgorithms/strings/Rotation.java
+++ b/src/main/java/com/thealgorithms/strings/Rotation.java
@@ -6,7 +6,9 @@
  * the string "abcdef" to the end of the string, so that the original string
  * becomes the string "cdefab"
  */
-public class Rotation {
+public final class Rotation {
+    private Rotation() {
+    }
 
     public static void main(String[] args) {
         assert rotation("abcdef", 2).equals("cdefab");
diff --git a/src/main/java/com/thealgorithms/strings/StringCompression.java b/src/main/java/com/thealgorithms/strings/StringCompression.java
index 28a3df743fc6..131bd4165493 100644
--- a/src/main/java/com/thealgorithms/strings/StringCompression.java
+++ b/src/main/java/com/thealgorithms/strings/StringCompression.java
@@ -4,7 +4,9 @@
  * string
  * @author Swarga-codes (https://github.com/Swarga-codes)
  */
-public class StringCompression {
+public final class StringCompression {
+    private StringCompression() {
+    }
     /**
      * Returns the compressed or encoded string
      *
diff --git a/src/main/java/com/thealgorithms/strings/Upper.java b/src/main/java/com/thealgorithms/strings/Upper.java
index 8f306a20e8f0..0fc87a9da318 100644
--- a/src/main/java/com/thealgorithms/strings/Upper.java
+++ b/src/main/java/com/thealgorithms/strings/Upper.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.strings;
 
-public class Upper {
+public final class Upper {
+    private Upper() {
+    }
 
     /**
      * Driver Code
diff --git a/src/main/java/com/thealgorithms/strings/ValidParentheses.java b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
index 5d3738522d44..b2759e5bcec9 100644
--- a/src/main/java/com/thealgorithms/strings/ValidParentheses.java
+++ b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
@@ -4,7 +4,9 @@
 //        the same type of brackets. Open brackets must be closed in the correct order. Every close
 //        bracket has a corresponding open bracket of the same type.
 
-public class ValidParentheses {
+public final class ValidParentheses {
+    private ValidParentheses() {
+    }
     public static boolean isValid(String s) {
         char[] stack = new char[s.length()];
         int head = 0;
diff --git a/src/main/java/com/thealgorithms/strings/WordLadder.java b/src/main/java/com/thealgorithms/strings/WordLadder.java
index e88acbd18586..025c43b15466 100644
--- a/src/main/java/com/thealgorithms/strings/WordLadder.java
+++ b/src/main/java/com/thealgorithms/strings/WordLadder.java
@@ -38,7 +38,9 @@
     All the words in wordList are unique.
  */
 
-class WordLadder {
+final class WordLadder {
+    private WordLadder() {
+    }
 
     /**
      * This function finds the ladderLength
diff --git a/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java b/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java
index 252517dc80cc..3619124745b4 100644
--- a/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java
+++ b/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java
@@ -2,7 +2,9 @@
 
 import java.util.HashMap;
 
-class longestNonRepeativeSubstring {
+final class longestNonRepeativeSubstring {
+    private longestNonRepeativeSubstring() {
+    }
 
     public static int lengthOfLongestSubstring(String s) {
         int max = 0, start = 0, i = 0;
diff --git a/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java b/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
index 75ab883386f5..ea366ad83b3d 100644
--- a/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
+++ b/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.strings.zigZagPattern;
 
-class zigZagPattern {
+final class zigZagPattern {
+    private zigZagPattern() {
+    }
 
     public static String encode(String s, int numRows) {
         if (numRows < 2 || s.length() < numRows) return s;
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java b/src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java
index 3bd197bf8bf8..9628e86b9bff 100644
--- a/src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java
+++ b/src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java
@@ -4,7 +4,9 @@
 import java.util.LinkedList;
 import java.util.Queue;
 
-public class TreeTestUtils {
+public final class TreeTestUtils {
+    private TreeTestUtils() {
+    }
 
     /**
      * Creates a binary tree with given values
diff --git a/src/test/java/com/thealgorithms/others/ArrayRightRotation.java b/src/test/java/com/thealgorithms/others/ArrayRightRotation.java
index a78ef81f32a4..11e4f44500b1 100644
--- a/src/test/java/com/thealgorithms/others/ArrayRightRotation.java
+++ b/src/test/java/com/thealgorithms/others/ArrayRightRotation.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.others;
 
-public class ArrayRightRotation {
+public final class ArrayRightRotation {
+    private ArrayRightRotation() {
+    }
     public static int[] rotateRight(int[] arr, int k) {
         if (arr == null || arr.length == 0 || k < 0) {
             throw new IllegalArgumentException("Invalid input");
diff --git a/src/test/java/com/thealgorithms/others/CRC16Test.java b/src/test/java/com/thealgorithms/others/CRC16Test.java
index 54e82f69aa88..bf309928bbf4 100644
--- a/src/test/java/com/thealgorithms/others/CRC16Test.java
+++ b/src/test/java/com/thealgorithms/others/CRC16Test.java
@@ -5,9 +5,6 @@
 import org.junit.jupiter.api.Test;
 
 class CRC16Test {
-
-    CRC16 crc = new CRC16();
-
     @Test
     void testCRC16() {
         // given
diff --git a/src/test/java/com/thealgorithms/strings/IsomorphicTest.java b/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
index 4601404c7817..0dac47551868 100644
--- a/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
+++ b/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
@@ -5,7 +5,9 @@
 
 import org.junit.jupiter.api.Test;
 
-public class IsomorphicTest {
+public final class IsomorphicTest {
+    private IsomorphicTest() {
+    }
 
     @Test
     public static void main(String[] args) {
diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java
index af8d20ab9b7e..b33037f37cfd 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java
@@ -5,8 +5,6 @@
 import org.junit.jupiter.api.Test;
 
 public class ReverseStringRecursiveTest {
-    ReverseStringRecursive stringRecursive = new ReverseStringRecursive();
-
     @Test
     void shouldAcceptWhenEmptyStringIsPassed() {
         String expected = "";

From d2ddec55e58763acd5651d0747e699ce4d5bdc93 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 8 May 2024 19:11:46 +0200
Subject: [PATCH 0148/1338] style: include
 `NAB_NEEDLESS_BOOLEAN_CONSTANT_CONVERSION` (#5149)

* style: use `assertFalse` and `assertTrue`

* style: include `NAB_NEEDLESS_BOOLEAN_CONSTANT_CONVERSION`
---
 spotbugs-exclude.xml                          |  3 ---
 .../ciphers/a5/CompositeLFSR.java             |  6 +++---
 .../graphs/DIJSKSTRAS_ALGORITHM.java          |  4 ++--
 .../datastructures/graphs/PrimMST.java        |  4 ++--
 .../greedyalgorithms/JobSequencing.java       |  4 ++--
 .../com/thealgorithms/sorts/CircleSort.java   |  2 +-
 .../bitmanipulation/IsEvenTest.java           | 11 ++++++----
 .../dynamicprogramming/SumOfSubsetTest.java   | 13 ++++++------
 .../maths/PythagoreanTripleTest.java          | 21 ++++++++++---------
 .../thealgorithms/others/TwoPointersTest.java | 13 ++++++------
 .../strings/ValidParenthesesTest.java         |  9 ++++----
 11 files changed, 47 insertions(+), 43 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 97c4e760eb6f..c2f9593a8129 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -126,9 +126,6 @@
     <Match>
         <Bug pattern="OCP_OVERLY_CONCRETE_PARAMETER" />
     </Match>
-    <Match>
-        <Bug pattern="NAB_NEEDLESS_BOOLEAN_CONSTANT_CONVERSION" />
-    </Match>
     <Match>
         <Bug pattern="LSC_LITERAL_STRING_COMPARISON" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java b/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java
index 12e93717a3de..3cac558237c2 100644
--- a/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java
+++ b/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java
@@ -26,10 +26,10 @@ public boolean clock() {
 
     private boolean getMajorityBit() {
         Map<Boolean, Integer> bitCount = new TreeMap<>();
-        bitCount.put(false, 0);
-        bitCount.put(true, 0);
+        bitCount.put(Boolean.FALSE, 0);
+        bitCount.put(Boolean.TRUE, 0);
 
         registers.forEach(lfsr -> bitCount.put(lfsr.getClockBit(), bitCount.get(lfsr.getClockBit()) + 1));
-        return bitCount.get(false) <= bitCount.get(true);
+        return bitCount.get(Boolean.FALSE) <= bitCount.get(Boolean.TRUE);
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java b/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
index 59f0d0116762..3eff999bc921 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
@@ -34,7 +34,7 @@ void dijkstra(int[][] graph, int src) {
 
         for (int i = 0; i < k; i++) {
             dist[i] = Integer.MAX_VALUE;
-            Set[i] = false;
+            Set[i] = Boolean.FALSE;
         }
 
         dist[src] = 0;
@@ -42,7 +42,7 @@ void dijkstra(int[][] graph, int src) {
         for (int c = 0; c < k - 1; c++) {
             int u = minDist(dist, Set);
 
-            Set[u] = true;
+            Set[u] = Boolean.TRUE;
 
             for (int v = 0; v < k; v++) {
                 if (!Set[v] && graph[u][v] != 0 && dist[u] != Integer.MAX_VALUE && dist[u] + graph[u][v] < dist[v]) {
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java b/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
index e61e2b6ac6ee..24fcbe7f90af 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
@@ -50,7 +50,7 @@ void primMST(int[][] graph) {
         // Initialize all keys as INFINITE
         for (int i = 0; i < V; i++) {
             key[i] = Integer.MAX_VALUE;
-            mstSet[i] = false;
+            mstSet[i] = Boolean.FALSE;
         }
 
         // Always include first 1st vertex in MST.
@@ -65,7 +65,7 @@ void primMST(int[][] graph) {
             int u = minKey(key, mstSet);
 
             // Add the picked vertex to the MST Set
-            mstSet[u] = true;
+            mstSet[u] = Boolean.TRUE;
 
             // Update key value and parent index of the adjacent
             // vertices of the picked vertex. Consider only those
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
index 69d52530d709..ceb664a31e8a 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java
@@ -31,7 +31,7 @@ public int compareTo(Job otherJob) {
     // Function to print the job sequence
     public static String findJobSequence(ArrayList<Job> jobs, int size) {
         Boolean[] slots = new Boolean[size];
-        Arrays.fill(slots, false);
+        Arrays.fill(slots, Boolean.FALSE);
 
         int[] result = new int[size];
 
@@ -40,7 +40,7 @@ public static String findJobSequence(ArrayList<Job> jobs, int size) {
             for (int j = jobs.get(i).deadline - 1; j >= 0; j--) {
                 if (!slots[j]) {
                     result[j] = i;
-                    slots[j] = true;
+                    slots[j] = Boolean.TRUE;
                     break;
                 }
             }
diff --git a/src/main/java/com/thealgorithms/sorts/CircleSort.java b/src/main/java/com/thealgorithms/sorts/CircleSort.java
index 756534a8ae4e..25c308b16e3c 100644
--- a/src/main/java/com/thealgorithms/sorts/CircleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CircleSort.java
@@ -25,7 +25,7 @@ private <T extends Comparable<T>> Boolean doSort(T[] array, int left, int right)
         boolean swapped = false;
 
         if (left == right) {
-            return false;
+            return Boolean.FALSE;
         }
 
         int low = left;
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java b/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java
index 674b79e57a08..0b2bfb0bb065 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java
@@ -1,14 +1,17 @@
 package com.thealgorithms.bitmanipulation;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
 class IsEvenTest {
     @Test
     void testIsEven() {
-        assertEquals(true, IsEven.isEven(2));
-        assertEquals(true, IsEven.isEven(-12));
-        assertEquals(false, IsEven.isEven(21));
+        assertTrue(IsEven.isEven(0));
+        assertTrue(IsEven.isEven(2));
+        assertTrue(IsEven.isEven(-12));
+        assertFalse(IsEven.isEven(21));
+        assertFalse(IsEven.isEven(-1));
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java
index 53c34937cbab..9df35447eefa 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.dynamicprogramming;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
@@ -8,10 +9,10 @@ class SumOfSubsetTest {
 
     @Test
     void basicCheck() {
-        assertEquals(false, SumOfSubset.subsetSum(new int[] {1, 2, 7, 10, 9}, 4, 14));
-        assertEquals(false, SumOfSubset.subsetSum(new int[] {2, 15, 1, 6, 7}, 4, 4));
-        assertEquals(true, SumOfSubset.subsetSum(new int[] {7, 3, 2, 5, 8}, 4, 14));
-        assertEquals(true, SumOfSubset.subsetSum(new int[] {4, 3, 2, 1}, 3, 5));
-        assertEquals(true, SumOfSubset.subsetSum(new int[] {1, 7, 2, 9, 10}, 4, 13));
+        assertFalse(SumOfSubset.subsetSum(new int[] {1, 2, 7, 10, 9}, 4, 14));
+        assertFalse(SumOfSubset.subsetSum(new int[] {2, 15, 1, 6, 7}, 4, 4));
+        assertTrue(SumOfSubset.subsetSum(new int[] {7, 3, 2, 5, 8}, 4, 14));
+        assertTrue(SumOfSubset.subsetSum(new int[] {4, 3, 2, 1}, 3, 5));
+        assertTrue(SumOfSubset.subsetSum(new int[] {1, 7, 2, 9, 10}, 4, 13));
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java b/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java
index 2dc2643c5878..1834c6e0fd1d 100644
--- a/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java
+++ b/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
@@ -8,14 +9,14 @@ public class PythagoreanTripleTest {
 
     @Test
     public void Testpythagoreantriple() {
-        assertEquals(true, PythagoreanTriple.isPythagTriple(3, 4, 5));
-        assertEquals(true, PythagoreanTriple.isPythagTriple(6, 8, 10));
-        assertEquals(true, PythagoreanTriple.isPythagTriple(9, 12, 15));
-        assertEquals(true, PythagoreanTriple.isPythagTriple(12, 16, 20));
-        assertEquals(true, PythagoreanTriple.isPythagTriple(15, 20, 25));
-        assertEquals(true, PythagoreanTriple.isPythagTriple(18, 24, 30));
-        assertEquals(false, PythagoreanTriple.isPythagTriple(5, 20, 30));
-        assertEquals(false, PythagoreanTriple.isPythagTriple(6, 8, 100));
-        assertEquals(false, PythagoreanTriple.isPythagTriple(-2, -2, 2));
+        assertTrue(PythagoreanTriple.isPythagTriple(3, 4, 5));
+        assertTrue(PythagoreanTriple.isPythagTriple(6, 8, 10));
+        assertTrue(PythagoreanTriple.isPythagTriple(9, 12, 15));
+        assertTrue(PythagoreanTriple.isPythagTriple(12, 16, 20));
+        assertTrue(PythagoreanTriple.isPythagTriple(15, 20, 25));
+        assertTrue(PythagoreanTriple.isPythagTriple(18, 24, 30));
+        assertFalse(PythagoreanTriple.isPythagTriple(5, 20, 30));
+        assertFalse(PythagoreanTriple.isPythagTriple(6, 8, 100));
+        assertFalse(PythagoreanTriple.isPythagTriple(-2, -2, 2));
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/TwoPointersTest.java b/src/test/java/com/thealgorithms/others/TwoPointersTest.java
index 8cadb031111b..e8fe41b0bdaf 100644
--- a/src/test/java/com/thealgorithms/others/TwoPointersTest.java
+++ b/src/test/java/com/thealgorithms/others/TwoPointersTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
@@ -10,34 +11,34 @@ public class TwoPointersTest {
     void twoPointersFirstTestCase() {
         int[] arr = {2, 6, 9, 22, 121};
         int key = 28;
-        assertEquals(true, TwoPointers.isPairedSum(arr, key));
+        assertTrue(TwoPointers.isPairedSum(arr, key));
     }
 
     @Test
     void twoPointersSecondTestCase() {
         int[] arr = {-1, -12, 12, 0, 8};
         int key = 0;
-        assertEquals(true, TwoPointers.isPairedSum(arr, key));
+        assertTrue(TwoPointers.isPairedSum(arr, key));
     }
 
     @Test
     void twoPointersThirdTestCase() {
         int[] arr = {12, 35, 12, 152, 0};
         int key = 13;
-        assertEquals(false, TwoPointers.isPairedSum(arr, key));
+        assertFalse(TwoPointers.isPairedSum(arr, key));
     }
 
     @Test
     void twoPointersFourthTestCase() {
         int[] arr = {-2, 5, -1, 52, 31};
         int key = -3;
-        assertEquals(true, TwoPointers.isPairedSum(arr, key));
+        assertTrue(TwoPointers.isPairedSum(arr, key));
     }
 
     @Test
     void twoPointersFiftiethTestCase() {
         int[] arr = {25, 1, 0, 61, 21};
         int key = 12;
-        assertEquals(false, TwoPointers.isPairedSum(arr, key));
+        assertFalse(TwoPointers.isPairedSum(arr, key));
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
index 6b7e04e972ea..22deb4b14d3c 100644
--- a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
+++ b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
@@ -8,16 +9,16 @@ public class ValidParenthesesTest {
 
     @Test
     void testOne() {
-        assertEquals(true, ValidParentheses.isValid("()"));
+        assertTrue(ValidParentheses.isValid("()"));
     }
 
     @Test
     void testTwo() {
-        assertEquals(true, ValidParentheses.isValid("()[]{}"));
+        assertTrue(ValidParentheses.isValid("()[]{}"));
     }
 
     @Test
     void testThree() {
-        assertEquals(false, ValidParentheses.isValid("(]"));
+        assertFalse(ValidParentheses.isValid("(]"));
     }
 }

From ee6924a2a072ef5325142b7d487166f96addf751 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 9 May 2024 16:34:57 +0200
Subject: [PATCH 0149/1338] style: include `PATH_TRAVERSAL_IN` (#5148)

---
 spotbugs-exclude.xml                          |  3 -
 .../com/thealgorithms/others/TopKWords.java   | 95 -------------------
 2 files changed, 98 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/others/TopKWords.java

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index c2f9593a8129..4f06c788fd42 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -286,7 +286,4 @@
     <Match>
         <Bug pattern="HARD_CODE_KEY" />
     </Match>
-    <Match>
-        <Bug pattern="PATH_TRAVERSAL_IN" />
-    </Match>
 </FindBugsFilter>
diff --git a/src/main/java/com/thealgorithms/others/TopKWords.java b/src/main/java/com/thealgorithms/others/TopKWords.java
deleted file mode 100644
index 4e30bbb4bdaa..000000000000
--- a/src/main/java/com/thealgorithms/others/TopKWords.java
+++ /dev/null
@@ -1,95 +0,0 @@
-package com.thealgorithms.others;
-
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Scanner;
-
-/* display the most frequent K words in the file and the times it appear
-in the file – shown in order (ignore case and periods) */
-public final class TopKWords {
-    private TopKWords() {
-    }
-
-    static class CountWords {
-
-        private String fileName;
-
-        CountWords(String fileName) {
-            this.fileName = fileName;
-        }
-
-        public Map<String, Integer> getDictionary() {
-            Map<String, Integer> dictionary = new HashMap<>();
-            FileInputStream fis = null;
-
-            try {
-                fis = new FileInputStream(fileName); // open the file
-                int in = 0;
-                String s = ""; // init a empty word
-                in = fis.read(); // read one character
-
-                while (-1 != in) {
-                    if (Character.isLetter((char) in)) {
-                        s += (char) in; // if get a letter, append to s
-                    } else {
-                        // this branch means an entire word has just been read
-                        if (s.length() > 0) {
-                            // see whether word exists or not
-                            if (dictionary.containsKey(s)) {
-                                // if exist, count++
-                                dictionary.put(s, dictionary.get(s) + 1);
-                            } else {
-                                // if not exist, initiate count of this word with 1
-                                dictionary.put(s, 1);
-                            }
-                        }
-                        s = ""; // reInit a empty word
-                    }
-                    in = fis.read();
-                }
-                return dictionary;
-            } catch (IOException e) {
-                e.printStackTrace();
-            } finally {
-                try {
-                    // you always have to close the I/O streams
-                    if (fis != null) {
-                        fis.close();
-                    }
-                } catch (IOException e) {
-                    e.printStackTrace();
-                }
-            }
-            return null;
-        }
-    }
-
-    public static void main(String[] args) {
-        // you can replace the filePath with yours
-        CountWords cw = new CountWords("/Users/lisanaaa/Desktop/words.txt");
-        Map<String, Integer> dictionary = cw.getDictionary(); // get the words dictionary: {word: frequency}
-
-        // we change the map to list for convenient sort
-        List<Map.Entry<String, Integer>> list = new ArrayList<>(dictionary.entrySet());
-
-        // sort by lambda valueComparator
-        list.sort(Comparator.comparing(m -> m.getValue()));
-
-        Scanner input = new Scanner(System.in);
-        int k = input.nextInt();
-        while (k > list.size()) {
-            System.out.println("Retype a number, your number is too large");
-            input = new Scanner(System.in);
-            k = input.nextInt();
-        }
-        for (int i = 0; i < k; i++) {
-            System.out.println(list.get(list.size() - i - 1));
-        }
-        input.close();
-    }
-}

From 7bff82f175912b76bc514597d08d85c32aca1a8c Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 9 May 2024 17:15:36 +0200
Subject: [PATCH 0150/1338] style: include `LEST_LOST_EXCEPTION_STACK_TRACE`
 (#5150)

---
 spotbugs-exclude.xml                                          | 3 ---
 .../datastructures/heaps/EmptyHeapException.java              | 4 ++++
 .../java/com/thealgorithms/datastructures/heaps/MaxHeap.java  | 2 +-
 .../java/com/thealgorithms/datastructures/heaps/MinHeap.java  | 2 +-
 4 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 4f06c788fd42..d8c83fb7ba08 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -252,9 +252,6 @@
     <Match>
         <Bug pattern="FCCD_FIND_CLASS_CIRCULAR_DEPENDENCY" />
     </Match>
-    <Match>
-        <Bug pattern="LEST_LOST_EXCEPTION_STACK_TRACE" />
-    </Match>
     <Match>
         <Bug pattern="PL_PARALLEL_LISTS" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/EmptyHeapException.java b/src/main/java/com/thealgorithms/datastructures/heaps/EmptyHeapException.java
index f18e4d4a960f..11af3f39981c 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/EmptyHeapException.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/EmptyHeapException.java
@@ -10,4 +10,8 @@ public class EmptyHeapException extends Exception {
     public EmptyHeapException(String message) {
         super(message);
     }
+
+    public EmptyHeapException(String message, Throwable cause) {
+        super(message, cause);
+    }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
index faf9fb92e5ca..4edf02679eb4 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
@@ -123,7 +123,7 @@ public HeapElement getElement() throws EmptyHeapException {
         try {
             return extractMax();
         } catch (Exception e) {
-            throw new EmptyHeapException("Heap is empty. Error retrieving element");
+            throw new EmptyHeapException("Heap is empty. Error retrieving element", e);
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
index 288a1932ddad..f220fe492399 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
@@ -117,7 +117,7 @@ public HeapElement getElement() throws EmptyHeapException {
         try {
             return extractMin();
         } catch (Exception e) {
-            throw new EmptyHeapException("Heap is empty. Error retrieving element");
+            throw new EmptyHeapException("Heap is empty. Error retrieving element", e);
         }
     }
 }

From 27c0978851864e4d5581aecc79e0ca2631a62310 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 9 May 2024 17:21:04 +0200
Subject: [PATCH 0151/1338] style: include `VA_FORMAT_STRING_USES_NEWLINE`
 (#5151)

---
 spotbugs-exclude.xml                                        | 3 ---
 .../hashmap/hashing/HashMapCuckooHashing.java               | 2 +-
 .../datastructures/hashmap/hashing/MainCuckooHashing.java   | 2 +-
 .../datastructures/lists/CreateAndDetectLoop.java           | 2 +-
 src/main/java/com/thealgorithms/others/TowerOfHanoi.java    | 2 +-
 .../com/thealgorithms/searches/MonteCarloTreeSearch.java    | 2 +-
 src/main/java/com/thealgorithms/sorts/InsertionSort.java    | 6 +++---
 7 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index d8c83fb7ba08..3f87cfef8725 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -8,9 +8,6 @@
     <Match>
         <Bug pattern="DMI_RANDOM_USED_ONLY_ONCE" />
     </Match>
-    <Match>
-        <Bug pattern="VA_FORMAT_STRING_USES_NEWLINE" />
-    </Match>
     <Match>
         <Bug pattern="SF_SWITCH_NO_DEFAULT" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
index 053751ebbc51..3fa6a812ec53 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
@@ -213,7 +213,7 @@ public boolean checkTableContainsKey(int key) {
     public double checkLoadFactor() {
         double factor = (double) size / tableSize;
         if (factor > .7) {
-            System.out.printf("Load factor is %.2f , rehashing table\n", factor);
+            System.out.printf("Load factor is %.2f , rehashing table%n", factor);
             reHashTableIncreasesTableSize();
         }
         return factor;
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
index f4e0f594de8f..6681253d7844 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
@@ -54,7 +54,7 @@ public static void main(String[] args) {
                 break;
             }
             case 6: {
-                System.out.printf("Load factor is: %.2f\n", h.checkLoadFactor());
+                System.out.printf("Load factor is: %.2f%n", h.checkLoadFactor());
                 break;
             }
             case 7: {
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java b/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
index 38133ad3491f..441c95702050 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
@@ -81,7 +81,7 @@ public static void main(String[] args) {
 
         System.out.println("Enter the number of elements to be inserted: ");
         int n = sc.nextInt();
-        System.out.printf("Enter the %d elements: \n", n);
+        System.out.printf("Enter the %d elements: %n", n);
         while (n-- > 0) {
             singlyLinkedList.insert(sc.nextInt());
         }
diff --git a/src/main/java/com/thealgorithms/others/TowerOfHanoi.java b/src/main/java/com/thealgorithms/others/TowerOfHanoi.java
index 8969c002cb22..2216799b987a 100644
--- a/src/main/java/com/thealgorithms/others/TowerOfHanoi.java
+++ b/src/main/java/com/thealgorithms/others/TowerOfHanoi.java
@@ -12,7 +12,7 @@ public static void shift(int n, String startPole, String intermediatePole, Strin
             // Shift function is called in recursion for swapping the n-1 disc from the startPole to
             // the intermediatePole
             shift(n - 1, startPole, endPole, intermediatePole);
-            System.out.format("Move %d from %s to %s\n", n, startPole, endPole); // Result Printing
+            System.out.format("Move %d from %s to %s%n", n, startPole, endPole); // Result Printing
             // Shift function is called in recursion for swapping the n-1 disc from the
             // intermediatePole to the endPole
             shift(n - 1, intermediatePole, startPole, endPole);
diff --git a/src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java b/src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java
index 58afc8dfc00d..268c33cef610 100644
--- a/src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java
+++ b/src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java
@@ -78,7 +78,7 @@ public Node monteCarloTreeSearch(Node rootNode) {
 
         winnerNode = getWinnerNode(rootNode);
         printScores(rootNode);
-        System.out.format("\nThe optimal node is: %02d\n", rootNode.childNodes.indexOf(winnerNode) + 1);
+        System.out.format("%nThe optimal node is: %02d%n", rootNode.childNodes.indexOf(winnerNode) + 1);
 
         return winnerNode;
     }
diff --git a/src/main/java/com/thealgorithms/sorts/InsertionSort.java b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
index 285755c3fcbc..3b8c286515bc 100644
--- a/src/main/java/com/thealgorithms/sorts/InsertionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
@@ -71,13 +71,13 @@ public static void main(String[] args) {
 
         InsertionSort insertionSort = new InsertionSort();
         double insertionTime = measureApproxExecTime(insertionSort::sort, randomArray);
-        System.out.printf("Original insertion time: %5.2f  sec.\n", insertionTime);
+        System.out.printf("Original insertion time: %5.2f  sec.%n", insertionTime);
 
         double insertionSentinelTime = measureApproxExecTime(insertionSort::sentinelSort, copyRandomArray);
-        System.out.printf("Sentinel insertion time: %5.2f  sec.\n", insertionSentinelTime);
+        System.out.printf("Sentinel insertion time: %5.2f  sec.%n", insertionSentinelTime);
 
         // ~ 1.5 time sentinel sort is faster, then classical Insertion sort implementation.
-        System.out.printf("Sentinel insertion is %f3.2 time faster than Original insertion sort\n", insertionTime / insertionSentinelTime);
+        System.out.printf("Sentinel insertion is %f3.2 time faster than Original insertion sort%n", insertionTime / insertionSentinelTime);
     }
 
     private static double measureApproxExecTime(Function<Double[], Double[]> sortAlgorithm, Double[] randomArray) {

From 52f15b2b082f617c93bf43c6a337ac993d8b18fa Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 9 May 2024 17:23:22 +0200
Subject: [PATCH 0152/1338] style: include `RV_RETURN_VALUE_IGNORED` (#5152)

---
 spotbugs-exclude.xml                                    | 3 ---
 src/main/java/com/thealgorithms/ciphers/HillCipher.java | 1 -
 2 files changed, 4 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 3f87cfef8725..0e8a67c73b73 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -104,9 +104,6 @@
     <Match>
         <Bug pattern="NP_IMMEDIATE_DEREFERENCE_OF_READLINE" />
     </Match>
-    <Match>
-        <Bug pattern="RV_RETURN_VALUE_IGNORED" />
-    </Match>
     <Match>
         <Bug pattern="EQ_COMPARETO_USE_OBJECT_EQUALS" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/ciphers/HillCipher.java b/src/main/java/com/thealgorithms/ciphers/HillCipher.java
index a858eb402939..14b98b3cc2f8 100644
--- a/src/main/java/com/thealgorithms/ciphers/HillCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/HillCipher.java
@@ -144,7 +144,6 @@ public static int determinant(int[][] a, int n) {
 
     // Function to implement Hill Cipher
     static void hillCipher(String message) {
-        message.toUpperCase();
         System.out.println("What do you want to process from the message?");
         System.out.println("Press 1: To Encrypt");
         System.out.println("Press 2: To Decrypt");

From bbe4a025df31f7ac2de98a5cd7d89e31b8a120f8 Mon Sep 17 00:00:00 2001
From: Godwill Christopher <chrisgodswill115@gmail.com>
Date: Sat, 11 May 2024 00:50:05 -0600
Subject: [PATCH 0153/1338] style: enable `FinalClass` in checkstyle (#5154)

---
 checkstyle.xml                                                  | 2 +-
 src/main/java/com/thealgorithms/datastructures/bags/Bag.java    | 2 +-
 .../thealgorithms/datastructures/dynamicarray/DynamicArray.java | 2 +-
 .../com/thealgorithms/datastructures/graphs/WelshPowell.java    | 2 +-
 .../datastructures/hashmap/hashing/Intersection.java            | 2 +-
 .../com/thealgorithms/datastructures/heaps/LeftistHeap.java     | 2 +-
 .../thealgorithms/datastructures/lists/CircleLinkedList.java    | 2 +-
 .../datastructures/lists/Merge_K_SortedLinkedlist.java          | 2 +-
 .../com/thealgorithms/datastructures/trees/GenericTree.java     | 2 +-
 .../com/thealgorithms/datastructures/trees/TreeRandomNode.java  | 2 +-
 src/main/java/com/thealgorithms/geometry/GrahamScan.java        | 2 +-
 .../java/com/thealgorithms/others/RotateMatrixBy90Degrees.java  | 2 +-
 12 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 5bbc5d72229a..912a6b2488e0 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -174,7 +174,7 @@
     <!-- Checks for class design                         -->
     <!-- See https://checkstyle.org/checks/design/index.html -->
     <!-- TODO <module name="DesignForExtension"/> -->
-    <!-- TODO <module name="FinalClass"/> -->
+    <module name="FinalClass"/>
     <module name="HideUtilityClassConstructor"/>
     <module name="InterfaceIsType"/>
     <!-- TODO <module name="VisibilityModifier"/> -->
diff --git a/src/main/java/com/thealgorithms/datastructures/bags/Bag.java b/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
index 66da3d34fcbf..ff5c832baeaf 100644
--- a/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
+++ b/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
@@ -13,7 +13,7 @@ public class Bag<Element> implements Iterable<Element> {
     private Node<Element> firstElement; // first element of the bag
     private int size; // size of bag
 
-    private static class Node<Element> {
+    private static final class Node<Element> {
 
         private Element content;
         private Node<Element> nextElement;
diff --git a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
index e1697f44cacb..186f301f622d 100644
--- a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
@@ -153,7 +153,7 @@ public Iterator<E> iterator() {
         return new DynamicArrayIterator();
     }
 
-    private class DynamicArrayIterator implements Iterator<E> {
+    private final class DynamicArrayIterator implements Iterator<E> {
 
         private int cursor;
 
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java b/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
index 3b823f02388d..0981638d4903 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
@@ -17,7 +17,7 @@ public final class WelshPowell {
     private WelshPowell() {
     }
 
-    static class Graph {
+    static final class Graph {
         private HashSet<Integer>[] adjacencyLists;
 
         private Graph(int vertices) {
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java
index ad3f617cef5a..54bd10de50fa 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java
@@ -12,7 +12,7 @@
 import java.util.List;
 import java.util.Map;
 
-public class Intersection {
+public final class Intersection {
 
     public static List<Integer> intersection(int[] arr1, int[] arr2) {
         if (arr1 == null || arr2 == null || arr1.length == 0 || arr2.length == 0) {
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
index cfec2b3c54bd..0e4bcc2c8b80 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
@@ -13,7 +13,7 @@
  */
 
 public class LeftistHeap {
-    private class Node {
+    private final class Node {
         private int element, npl;
         private Node left, right;
 
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
index c42b10455d14..6eb9d75fe58f 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
@@ -2,7 +2,7 @@
 
 public class CircleLinkedList<E> {
 
-    private static class Node<E> {
+    private static final class Node<E> {
 
         Node<E> next;
         E value;
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java b/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java
index 7206ccecf25e..d98335b1e5b9 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java
@@ -43,7 +43,7 @@ Node mergeKList(Node[] a, int N) {
         return head;
     }
 
-    private class Node {
+    private final class Node {
 
         private int data;
         private Node next;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java b/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java
index d348467815c7..39af10bac813 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java
@@ -16,7 +16,7 @@
  */
 public class GenericTree {
 
-    private static class Node {
+    private static final class Node {
 
         int data;
         ArrayList<Node> child = new ArrayList<>();
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java b/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java
index eeb253d9d342..b1123a224223 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java
@@ -26,7 +26,7 @@ the inOrder() method to store the values in the arraylist, then find the size of
 
 public class TreeRandomNode {
 
-    private class Node {
+    private final class Node {
 
         int item;
         Node left, right;
diff --git a/src/main/java/com/thealgorithms/geometry/GrahamScan.java b/src/main/java/com/thealgorithms/geometry/GrahamScan.java
index 9122c6f6f3cc..4f4aebaed971 100644
--- a/src/main/java/com/thealgorithms/geometry/GrahamScan.java
+++ b/src/main/java/com/thealgorithms/geometry/GrahamScan.java
@@ -126,7 +126,7 @@ public Comparator<Point> polarOrder() {
             return new PolarOrder();
         }
 
-        private class PolarOrder implements Comparator<Point> {
+        private final class PolarOrder implements Comparator<Point> {
             public int compare(Point p1, Point p2) {
                 int dx1 = p1.x - x;
                 int dy1 = p1.y - y;
diff --git a/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java b/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
index 081b0d16dce8..985b8b2631a9 100644
--- a/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
+++ b/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
@@ -6,7 +6,7 @@
  */
 import java.util.Scanner;
 
-class Rotate_by_90_degrees {
+final class Rotate_by_90_degrees {
     private Rotate_by_90_degrees() {
     }
 

From cb401fed69258f3ccc0484ccd9f588c10af0dd32 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 11 May 2024 14:31:11 +0200
Subject: [PATCH 0154/1338] chore: configure PMD (#5155)

---
 .github/workflows/build.yml |  2 +
 pmd-exclude.properties      | 95 +++++++++++++++++++++++++++++++++++++
 pom.xml                     | 11 +++++
 3 files changed, 108 insertions(+)
 create mode 100644 pmd-exclude.properties

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 39a690f9aec4..faf5dd6aa9bb 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -33,3 +33,5 @@ jobs:
         run: mvn checkstyle:check
       - name: SpotBugs
         run: mvn spotbugs:check
+      - name: PMD
+        run: mvn pmd:check
diff --git a/pmd-exclude.properties b/pmd-exclude.properties
new file mode 100644
index 000000000000..fb8470d8ba81
--- /dev/null
+++ b/pmd-exclude.properties
@@ -0,0 +1,95 @@
+com.thealgorithms.bitmanipulation.SingleBitOperations=UselessParentheses
+com.thealgorithms.ciphers.AffineCipher=UselessParentheses
+com.thealgorithms.ciphers.ColumnarTranspositionCipher=UnnecessaryFullyQualifiedName
+com.thealgorithms.ciphers.DES=UselessParentheses
+com.thealgorithms.ciphers.HillCipher=UselessParentheses
+com.thealgorithms.ciphers.RSA=UselessParentheses
+com.thealgorithms.conversions.AnyBaseToAnyBase=UselessParentheses
+com.thealgorithms.conversions.AnytoAny=UselessParentheses
+com.thealgorithms.conversions.HexToOct=UselessParentheses
+com.thealgorithms.conversions.IntegerToRoman=UnnecessaryFullyQualifiedName
+com.thealgorithms.datastructures.crdt.LWWElementSet=UselessParentheses
+com.thealgorithms.datastructures.crdt.Pair=UnusedPrivateField
+com.thealgorithms.datastructures.graphs.A_Star=UselessParentheses
+com.thealgorithms.datastructures.graphs.AdjacencyMatrixGraph=CollapsibleIfStatements,UnnecessaryFullyQualifiedName,UselessParentheses
+com.thealgorithms.datastructures.graphs.BipartiteGrapfDFS=CollapsibleIfStatements
+com.thealgorithms.datastructures.graphs.Kruskal=UselessParentheses
+com.thealgorithms.datastructures.hashmap.hashing.HashMapCuckooHashing=UselessParentheses
+com.thealgorithms.datastructures.heaps.FibonacciHeap=UselessParentheses
+com.thealgorithms.datastructures.heaps.HeapElement=UselessParentheses
+com.thealgorithms.datastructures.heaps.HeapNode=UselessParentheses
+com.thealgorithms.datastructures.lists.DoublyLinkedList=UselessParentheses
+com.thealgorithms.datastructures.lists.SearchSinglyLinkedListRecursion=UselessParentheses
+com.thealgorithms.datastructures.lists.SinglyLinkedList=UnusedLocalVariable
+com.thealgorithms.datastructures.queues.PriorityQueue=UselessParentheses
+com.thealgorithms.datastructures.stacks.NodeStack=UnnecessaryFullyQualifiedName,UnusedFormalParameter
+com.thealgorithms.datastructures.stacks.StackArray=UselessParentheses
+com.thealgorithms.datastructures.trees.CheckBinaryTreeIsValidBST=UselessParentheses
+com.thealgorithms.datastructures.trees.Point=OverrideBothEqualsAndHashcode
+com.thealgorithms.datastructures.trees.SegmentTree=UselessParentheses
+com.thealgorithms.devutils.nodes.LargeTreeNode=UselessParentheses
+com.thealgorithms.devutils.nodes.SimpleNode=UselessParentheses
+com.thealgorithms.devutils.nodes.SimpleTreeNode=UselessParentheses
+com.thealgorithms.devutils.nodes.TreeNode=UselessParentheses
+com.thealgorithms.divideandconquer.ClosestPair=UnnecessaryFullyQualifiedName,UselessParentheses
+com.thealgorithms.divideandconquer.Point=UselessParentheses
+com.thealgorithms.dynamicprogramming.KnapsackMemoization=UselessParentheses
+com.thealgorithms.dynamicprogramming.MatrixChainMultiplication=UselessParentheses
+com.thealgorithms.dynamicprogramming.ShortestSuperSequence=UselessParentheses
+com.thealgorithms.dynamicprogramming.UniquePaths=UnnecessarySemicolon
+com.thealgorithms.dynamicprogramming.WineProblem=UselessParentheses
+com.thealgorithms.maths.BinomialCoefficient=UselessParentheses
+com.thealgorithms.maths.Complex=UselessParentheses
+com.thealgorithms.maths.DistanceFormulaTest=UnnecessaryFullyQualifiedName
+com.thealgorithms.maths.DudeneyNumber=UselessParentheses
+com.thealgorithms.maths.FibonacciJavaStreamsTest=BigIntegerInstantiation
+com.thealgorithms.maths.Gaussian=UselessParentheses
+com.thealgorithms.maths.GcdSolutionWrapper=UselessParentheses
+com.thealgorithms.maths.HeronsFormula=UselessParentheses
+com.thealgorithms.maths.KaprekarNumbers=UselessParentheses
+com.thealgorithms.maths.KeithNumber=UselessParentheses
+com.thealgorithms.maths.LeonardoNumber=UselessParentheses
+com.thealgorithms.maths.LinearDiophantineEquationsSolver=UselessParentheses
+com.thealgorithms.maths.MatrixUtil=BigIntegerInstantiation,UselessParentheses
+com.thealgorithms.maths.RomanNumeralUtil=UselessParentheses
+com.thealgorithms.maths.SecondMinMax=UselessParentheses
+com.thealgorithms.maths.SecondMinMaxTest=UnnecessaryFullyQualifiedName
+com.thealgorithms.maths.StandardDeviation=UselessParentheses
+com.thealgorithms.maths.SumOfArithmeticSeries=UselessParentheses
+com.thealgorithms.maths.TrinomialTriangle=UselessParentheses
+com.thealgorithms.maths.VampireNumber=CollapsibleIfStatements
+com.thealgorithms.maths.Volume=UselessParentheses
+com.thealgorithms.matrixexponentiation.Fibonacci=UnnecessaryFullyQualifiedName
+com.thealgorithms.misc.Sparsity=UselessParentheses
+com.thealgorithms.misc.ThreeSumProblem=UselessParentheses
+com.thealgorithms.misc.WordBoggle=UselessParentheses
+com.thealgorithms.others.CRC16=UselessParentheses
+com.thealgorithms.others.Damm=UnnecessaryFullyQualifiedName
+com.thealgorithms.others.Luhn=UnnecessaryFullyQualifiedName
+com.thealgorithms.others.Mandelbrot=UselessParentheses
+com.thealgorithms.others.MaximumSumOfDistinctSubarraysWithLengthK=CollapsibleIfStatements
+com.thealgorithms.others.MiniMaxAlgorithm=UselessParentheses
+com.thealgorithms.others.PageRank=UselessParentheses
+com.thealgorithms.others.PerlinNoise=UselessParentheses
+com.thealgorithms.others.QueueUsingTwoStacks=UselessParentheses
+com.thealgorithms.others.QueueWithStack=UselessParentheses
+com.thealgorithms.others.Trieac=UselessParentheses
+com.thealgorithms.others.Verhoeff=UnnecessaryFullyQualifiedName
+com.thealgorithms.searches.InterpolationSearch=UselessParentheses
+com.thealgorithms.searches.KMPSearch=UselessParentheses
+com.thealgorithms.searches.LinearSearchThread=EmptyCatchBlock
+com.thealgorithms.searches.RabinKarpAlgorithm=UselessParentheses
+com.thealgorithms.sorts.BubbleSortRecursion=UselessParentheses
+com.thealgorithms.sorts.CircleSort=EmptyControlStatement
+com.thealgorithms.sorts.CombSort=UselessParentheses
+com.thealgorithms.sorts.DutchNationalFlagSort=UselessParentheses
+com.thealgorithms.sorts.LinkListSort=EmptyControlStatement,UnusedLocalVariable
+com.thealgorithms.sorts.MergeSortNoExtraSpace=UselessParentheses
+com.thealgorithms.sorts.PigeonholeSort=UselessParentheses
+com.thealgorithms.sorts.RadixSort=UselessParentheses
+com.thealgorithms.sorts.WiggleSort=UselessParentheses
+com.thealgorithms.stacks.PostfixToInfix=UselessParentheses
+com.thealgorithms.strings.HorspoolSearch=UnnecessaryFullyQualifiedName,UselessParentheses
+com.thealgorithms.strings.MyAtoi=UselessParentheses
+com.thealgorithms.strings.Palindrome=UselessParentheses
+com.thealgorithms.strings.Solution=CollapsibleIfStatements
diff --git a/pom.xml b/pom.xml
index 738461cc6f4d..96478c484837 100644
--- a/pom.xml
+++ b/pom.xml
@@ -135,6 +135,17 @@
                     </plugins>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-pmd-plugin</artifactId>
+                <version>3.22.0</version>
+                <configuration>
+                    <printFailingErrors>true</printFailingErrors>
+                    <includeTests>true</includeTests>
+                    <linkXRef>false</linkXRef>
+                    <excludeFromFailureFile>pmd-exclude.properties</excludeFromFailureFile>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 </project>

From cf6c87c35c309e754e6029e135c2801d143ff426 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 11 May 2024 16:36:17 +0200
Subject: [PATCH 0155/1338] style: make `SubsetCount` a proper utility (#5153)

---
 spotbugs-exclude.xml                                   |  3 ---
 .../thealgorithms/dynamicprogramming/SubsetCount.java  |  8 +++++---
 .../dynamicprogramming/SubsetCountTest.java            | 10 ++++------
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 0e8a67c73b73..1f53feafb3be 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -74,9 +74,6 @@
     <Match>
         <Bug pattern="DM_BOXED_PRIMITIVE_FOR_PARSING" />
     </Match>
-    <Match>
-        <Bug pattern="MS_SHOULD_BE_FINAL" />
-    </Match>
     <Match>
         <Bug pattern="UWF_UNWRITTEN_FIELD" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java
index ef1c6c8f89f0..af31294f7e0e 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java
@@ -6,7 +6,9 @@
  * StackOverflow(https://stackoverflow.com/questions/22891076/count-number-of-subsets-with-sum-equal-to-k)
  * @author Samrat Podder(https://github.com/samratpodder)
  */
-public class SubsetCount {
+public final class SubsetCount {
+    private SubsetCount() {
+    }
 
     /**
      * Dynamic Programming Implementation.
@@ -16,7 +18,7 @@ public class SubsetCount {
      * @param target is the sum of each element of the subset taken together
      *
      */
-    public int getCount(int[] arr, int target) {
+    public static int getCount(int[] arr, int target) {
         /**
          * Base Cases - If target becomes zero, we have reached the required sum for the subset
          * If we reach the end of the array arr then, either if target==arr[end], then we add one to
@@ -46,7 +48,7 @@ public int getCount(int[] arr, int target) {
      * @param arr is the input array on which subsets are  to searched
      * @param target is the sum of each element of the subset taken together
      */
-    public int getCountSO(int[] arr, int target) {
+    public static int getCountSO(int[] arr, int target) {
         int n = arr.length;
         int[] prev = new int[target + 1];
         prev[0] = 1;
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java
index 13f7b6f9c408..c76f89deb600 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java
@@ -5,27 +5,25 @@
 import org.junit.jupiter.api.Test;
 
 public class SubsetCountTest {
-    public static SubsetCount obj = new SubsetCount();
-
     @Test
     void hasMultipleSubset() {
         int[] arr = new int[] {1, 2, 3, 3};
-        assertEquals(3, obj.getCount(arr, 6));
+        assertEquals(3, SubsetCount.getCount(arr, 6));
     }
     @Test
     void singleElementSubset() {
         int[] arr = new int[] {1, 1, 1, 1};
-        assertEquals(4, obj.getCount(arr, 1));
+        assertEquals(4, SubsetCount.getCount(arr, 1));
     }
 
     @Test
     void hasMultipleSubsetSO() {
         int[] arr = new int[] {1, 2, 3, 3};
-        assertEquals(3, obj.getCountSO(arr, 6));
+        assertEquals(3, SubsetCount.getCountSO(arr, 6));
     }
     @Test
     void singleSubsetSO() {
         int[] arr = new int[] {1, 1, 1, 1};
-        assertEquals(1, obj.getCountSO(arr, 4));
+        assertEquals(1, SubsetCount.getCountSO(arr, 4));
     }
 }

From 319d5143cc0919c0749898e0732f32acee1f4aef Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 12 May 2024 11:05:33 +0200
Subject: [PATCH 0156/1338] refactor: cleanup `DudeneyNumber` (#5156)

---
 pmd-exclude.properties                        |  1 -
 .../thealgorithms/maths/DudeneyNumber.java    | 22 +++++------------
 .../maths/DudeneyNumberTest.java              | 24 +++++++++++++------
 3 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index fb8470d8ba81..f2e35f43887e 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -41,7 +41,6 @@ com.thealgorithms.dynamicprogramming.WineProblem=UselessParentheses
 com.thealgorithms.maths.BinomialCoefficient=UselessParentheses
 com.thealgorithms.maths.Complex=UselessParentheses
 com.thealgorithms.maths.DistanceFormulaTest=UnnecessaryFullyQualifiedName
-com.thealgorithms.maths.DudeneyNumber=UselessParentheses
 com.thealgorithms.maths.FibonacciJavaStreamsTest=BigIntegerInstantiation
 com.thealgorithms.maths.Gaussian=UselessParentheses
 com.thealgorithms.maths.GcdSolutionWrapper=UselessParentheses
diff --git a/src/main/java/com/thealgorithms/maths/DudeneyNumber.java b/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
index c8c8820d3a5f..88e008cf8a08 100644
--- a/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
@@ -11,28 +11,18 @@ private DudeneyNumber() {
     }
 
     // returns True if the number is a Dudeney number and False if it is not a Dudeney number.
-    public static boolean isDudeney(int n) {
+    public static boolean isDudeney(final int n) {
+        if (n <= 0) {
+            throw new IllegalArgumentException("Input must me positive.");
+        }
         // Calculating Cube Root
-        int cube_root = (int) (Math.round((Math.pow(n, 1.0 / 3.0))));
+        final int cube_root = (int) Math.round(Math.pow(n, 1.0 / 3.0));
         // If the number is not a perfect cube the method returns false.
         if (cube_root * cube_root * cube_root != n) {
             return false;
         }
-        int sum_of_digits = 0; // Stores the sums of the digits of the entered number
-        int temp = n; // A temporary variable to store the entered number
-        // Loop to calculate the sum of the digits.
-        while (temp > 0) {
-            // Extracting the Last digit of the number
-            int rem = temp % 10;
-
-            // Calculating the sum of digits.
-            sum_of_digits += rem;
-
-            // Removing the last digit
-            temp /= 10;
-        }
 
         // If the cube root of the number is not equal to the sum of its digits, we return false.
-        return cube_root == sum_of_digits;
+        return cube_root == SumOfDigits.sumOfDigits(n);
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java b/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java
index 718a1def5eb8..cd93edfae61d 100644
--- a/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java
@@ -1,18 +1,28 @@
 package com.thealgorithms.maths;
 
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 class DudeneyNumberTest {
+    @ParameterizedTest
+    @CsvSource({"1", "512", "4913", "5832", "17576", "19683"})
+    void positiveDudeneyBase10Power3(final int n) {
+        assertTrue(DudeneyNumber.isDudeney(n));
+    }
 
-    @Test
-    void isDudeney() {
-        final int validDudeneyNumber = 512;
-        final int invalidDudeneyNumber = 125;
+    @ParameterizedTest
+    @CsvSource({"2", "19", "21", "125", "27", "343", "729", "19682", "19684"})
+    void negativeDudeneyBase10Power3(final int n) {
+        assertFalse(DudeneyNumber.isDudeney(n));
+    }
 
-        assertTrue(() -> DudeneyNumber.isDudeney(validDudeneyNumber));
-        assertFalse(() -> DudeneyNumber.isDudeney(invalidDudeneyNumber));
+    @ParameterizedTest
+    @CsvSource({"0", "-1"})
+    void throwsInputLessThanOne(final int n) {
+        assertThrows(IllegalArgumentException.class, () -> DudeneyNumber.isDudeney(n));
     }
 }

From 5703be59539bc8886a83af57734747b800e34fa0 Mon Sep 17 00:00:00 2001
From: Godwill Christopher <chrisgodswill115@gmail.com>
Date: Sun, 12 May 2024 03:38:07 -0600
Subject: [PATCH 0157/1338] style: enable EqualsHashCode in checkstyle (#5157)

---
 checkstyle.xml                                               | 2 +-
 .../java/com/thealgorithms/datastructures/trees/KDTree.java  | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 912a6b2488e0..444b366ddee7 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -161,7 +161,7 @@
     <!-- Checks for common coding problems               -->
     <!-- See https://checkstyle.org/checks/coding/index.html -->
     <module name="EmptyStatement"/>
-    <!-- TODO <module name="EqualsHashCode"/> -->
+    <module name="EqualsHashCode"/>
     <!-- TODO <module name="HiddenField"/> -->
     <module name="IllegalInstantiation"/>
     <!-- TODO <module name="InnerAssignment"/> -->
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java b/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
index c3be07eef0ab..cdcbafa51658 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
@@ -81,6 +81,11 @@ public boolean equals(Object obj) {
             return false;
         }
 
+        @Override
+        public int hashCode() {
+            return Arrays.hashCode(coordinates);
+        }
+
         @Override
         public String toString() {
             return Arrays.toString(coordinates);

From bbef89c885a892bfd92f44728bbaf51dd2c3211c Mon Sep 17 00:00:00 2001
From: Godwill Christopher <chrisgodswill115@gmail.com>
Date: Sun, 12 May 2024 04:37:14 -0600
Subject: [PATCH 0158/1338] refactor: simplify logic of `Point::equals` in
 `KDTree` (#5158)

---
 src/main/java/com/thealgorithms/datastructures/trees/KDTree.java | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java b/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
index cdcbafa51658..e5528c392bb8 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
@@ -75,7 +75,6 @@ public int getDimension() {
         @Override
         public boolean equals(Object obj) {
             if (obj instanceof Point other) {
-                if (other.getDimension() != this.getDimension()) return false;
                 return Arrays.equals(other.coordinates, this.coordinates);
             }
             return false;

From f8e62fbb90a97b86cf9c103e18f5892ca502ba16 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 14 May 2024 18:02:08 +0200
Subject: [PATCH 0159/1338] Chore(deps): bump gitpod/workspace-java-17 from
 2024-04-29-23-03-42 to 2024-05-13-09-12-40 (#5161)

Chore(deps): bump gitpod/workspace-java-17

Bumps gitpod/workspace-java-17 from 2024-04-29-23-03-42 to 2024-05-13-09-12-40.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-17
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 07b853b087de..1f0020db1f0a 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-17:2024-04-29-23-03-42
+FROM gitpod/workspace-java-17:2024-05-13-09-12-40
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 0f42e995a42a8657e9ba53732392fb74e634a1a1 Mon Sep 17 00:00:00 2001
From: Godwill Christopher <chrisgodswill115@gmail.com>
Date: Thu, 16 May 2024 10:46:03 -0600
Subject: [PATCH 0160/1338] style: enabled `InnerAssignment` in checkstyle
 (#5162)

* style: enabled InnerAssignment in checkstyle

* Refactor code formatting in KnapsackMemoization.java and UnionFind.java

* style: remove redundant blank line

* style: mark `includeCurrentItem` and `excludeCurrentItem` as `final`

* style: remove `KnapsackMemoization` from `pmd-exclude.properties`

* style: use `final`

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 checkstyle.xml                                        |  2 +-
 pmd-exclude.properties                                |  1 -
 .../java/com/thealgorithms/ciphers/ProductCipher.java |  4 ++--
 .../datastructures/dynamicarray/DynamicArray.java     |  3 ++-
 .../datastructures/heaps/LeftistHeap.java             |  3 ++-
 .../datastructures/queues/CircularQueue.java          |  3 ++-
 .../datastructures/queues/LinkedQueue.java            |  7 +++++--
 .../datastructures/trees/PrintTopViewofTree.java      |  3 ++-
 .../datastructures/trees/RedBlackBST.java             |  3 ++-
 .../dynamicprogramming/KnapsackMemoization.java       | 11 +++++++++--
 .../LongestAlternatingSubsequence.java                |  3 ++-
 .../dynamicprogramming/NewManShanksPrime.java         |  3 ++-
 .../com/thealgorithms/maths/LeastCommonMultiple.java  |  6 ++++--
 .../com/thealgorithms/others/SieveOfEratosthenes.java |  3 ++-
 .../java/com/thealgorithms/searches/UnionFind.java    |  5 ++++-
 15 files changed, 41 insertions(+), 19 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 444b366ddee7..ce584392b089 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -164,7 +164,7 @@
     <module name="EqualsHashCode"/>
     <!-- TODO <module name="HiddenField"/> -->
     <module name="IllegalInstantiation"/>
-    <!-- TODO <module name="InnerAssignment"/> -->
+    <module name="InnerAssignment"/>
     <!-- TODO <module name="MagicNumber"/> -->
     <!-- TODO <module name="MissingSwitchDefault"/> -->
     <!-- TODO <module name="MultipleVariableDeclarations"/> -->
diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index f2e35f43887e..8722f126f6d5 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -33,7 +33,6 @@ com.thealgorithms.devutils.nodes.SimpleTreeNode=UselessParentheses
 com.thealgorithms.devutils.nodes.TreeNode=UselessParentheses
 com.thealgorithms.divideandconquer.ClosestPair=UnnecessaryFullyQualifiedName,UselessParentheses
 com.thealgorithms.divideandconquer.Point=UselessParentheses
-com.thealgorithms.dynamicprogramming.KnapsackMemoization=UselessParentheses
 com.thealgorithms.dynamicprogramming.MatrixChainMultiplication=UselessParentheses
 com.thealgorithms.dynamicprogramming.ShortestSuperSequence=UselessParentheses
 com.thealgorithms.dynamicprogramming.UniquePaths=UnnecessarySemicolon
diff --git a/src/main/java/com/thealgorithms/ciphers/ProductCipher.java b/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
index fb49d6cd61db..fb63ed9b6ef9 100644
--- a/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
@@ -26,8 +26,8 @@ public static void main(String[] args) {
 
             // Transposition encryption
             String transpositionInput = substitutionOutput.toString();
-            int modulus;
-            if ((modulus = transpositionInput.length() % n) != 0) {
+            int modulus = transpositionInput.length() % n;
+            if (modulus != 0) {
                 modulus = n - modulus;
 
                 for (; modulus != 0; modulus--) {
diff --git a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
index 186f301f622d..cfec2e3b2c37 100644
--- a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
@@ -121,7 +121,8 @@ private void fastRemove(final Object[] elements, final int index) {
             System.arraycopy(elements, index + 1, elements, index, newSize - index);
         }
 
-        elements[this.size = newSize] = null;
+        this.size = newSize;
+        this.elements[this.size] = null;
     }
 
     private E getElement(final int index) {
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
index 0e4bcc2c8b80..d21f8d6e71dc 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
@@ -20,7 +20,8 @@ private final class Node {
         // Node constructor setting the data element and left/right pointers to null
         private Node(int element) {
             this.element = element;
-            left = right = null;
+            left = null;
+            right = null;
             npl = 0;
         }
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
index 9530c5a69d8c..cd3761bdcf75 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
@@ -54,7 +54,8 @@ public int deQueue() {
             int res = arr[beginningOfQueue];
             arr[beginningOfQueue] = Integer.MIN_VALUE;
             if (beginningOfQueue == topOfQueue) {
-                beginningOfQueue = topOfQueue = -1;
+                beginningOfQueue = -1;
+                topOfQueue = -1;
             } else if (beginningOfQueue + 1 == size) {
                 beginningOfQueue = 0;
             } else {
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
index b552ac2918a3..8a788317c372 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
@@ -44,7 +44,9 @@ static class Node<T> {
      * Init LinkedQueue
      */
     public LinkedQueue() {
-        front = rear = new Node<>();
+
+        front = new Node<>();
+        rear = front;
     }
 
     /**
@@ -146,7 +148,8 @@ public boolean hasNext() {
 
             @Override
             public T next() {
-                return (node = node.next).data;
+                node = node.next;
+                return node.data;
             }
         };
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java b/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
index e30a52929519..0fcf1324a4ce 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
@@ -15,7 +15,8 @@ class TreeNode {
     // Constructor
     TreeNode(int key) {
         this.key = key;
-        left = right = null;
+        left = null;
+        right = null;
     }
 }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java b/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
index ebdcba40ae7c..f2954f28495f 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
@@ -201,7 +201,8 @@ Node treeMinimum(Node subTreeRoot) {
     }
 
     boolean delete(Node z) {
-        if ((z = findNode(z, root)) == null) {
+        Node result = findNode(z, root);
+        if (result == null) {
             return false;
         }
         Node x;
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java b/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java
index 290e98caebae..396efb1a7893 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java
@@ -40,8 +40,15 @@ int solveKnapsackRecursive(int capacity, int[] weights, int[] profits, int numOf
             dpTable[numOfItems][capacity] = solveKnapsackRecursive(capacity, weights, profits, numOfItems - 1, dpTable);
             return dpTable[numOfItems][capacity];
         } else {
-            // Return value of table after storing
-            return dpTable[numOfItems][capacity] = Math.max((profits[numOfItems - 1] + solveKnapsackRecursive(capacity - weights[numOfItems - 1], weights, profits, numOfItems - 1, dpTable)), solveKnapsackRecursive(capacity, weights, profits, numOfItems - 1, dpTable));
+            // case 1. include the item, if it is less than the capacity
+            final int includeCurrentItem = profits[numOfItems - 1] + solveKnapsackRecursive(capacity - weights[numOfItems - 1], weights, profits, numOfItems - 1, dpTable);
+
+            // case 2. exclude the item if it is more than the capacity
+            final int excludeCurrentItem = solveKnapsackRecursive(capacity, weights, profits, numOfItems - 1, dpTable);
+
+            // Store the value of function call stack in table and return
+            dpTable[numOfItems][capacity] = Math.max(includeCurrentItem, excludeCurrentItem);
+            return dpTable[numOfItems][capacity];
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
index c5b7ea2b9a18..51a78a853e03 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
@@ -34,7 +34,8 @@ static int AlternatingLength(int[] arr, int n) {
         int[][] las = new int[n][2]; // las = LongestAlternatingSubsequence
 
         for (int i = 0; i < n; i++) {
-            las[i][0] = las[i][1] = 1;
+            las[i][0] = 1;
+            las[i][1] = 1;
         }
 
         int result = 1; // Initialize result
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java b/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
index ff67500b0585..7bc383656581 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
@@ -15,7 +15,8 @@ private NewManShanksPrime() {
     public static boolean nthManShanksPrime(int n, int expected_answer) {
         int[] a = new int[n + 1];
         // array of n+1 size is initialized
-        a[0] = a[1] = 1;
+        a[0] = 1;
+        a[1] = 1;
         // The 0th and 1st index position values are fixed. They are initialized as 1
         for (int i = 2; i <= n; i++) {
             a[i] = 2 * a[i - 1] + a[i - 2];
diff --git a/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java b/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
index ae887470fa33..228ff0b50b2b 100644
--- a/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
+++ b/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
@@ -36,9 +36,11 @@ public static int lcm(int num1, int num2) {
          * value selection for the numerator
          */
         if (num1 > num2) {
-            high = num3 = num1;
+            high = num1;
+            num3 = num1;
         } else {
-            high = num3 = num2;
+            high = num2;
+            num3 = num2;
         }
 
         while (num1 != 0) {
diff --git a/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java b/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java
index 1fd9ae288920..6a3412500d11 100644
--- a/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java
+++ b/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java
@@ -19,7 +19,8 @@ private static Type[] sievePrimesTill(int n) {
         checkInput(n);
         Type[] isPrimeArray = new Type[n + 1];
         Arrays.fill(isPrimeArray, Type.PRIME);
-        isPrimeArray[0] = isPrimeArray[1] = Type.NOT_PRIME;
+        isPrimeArray[0] = Type.NOT_PRIME;
+        isPrimeArray[1] = Type.NOT_PRIME;
 
         double cap = Math.sqrt(n);
         for (int i = 2; i <= cap; i++) {
diff --git a/src/main/java/com/thealgorithms/searches/UnionFind.java b/src/main/java/com/thealgorithms/searches/UnionFind.java
index fc5dbd801ffa..2effdf37bea5 100644
--- a/src/main/java/com/thealgorithms/searches/UnionFind.java
+++ b/src/main/java/com/thealgorithms/searches/UnionFind.java
@@ -25,7 +25,10 @@ public int find(int i) {
             return i;
         }
 
-        return p[i] = find(parent);
+        final int result = find(parent);
+        p[i] = result;
+
+        return result;
     }
 
     public void union(int x, int y) {

From bf9d0ed66a867c8197f1cd80c48b6818d7eefee3 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 17 May 2024 11:54:22 +0200
Subject: [PATCH 0161/1338] fix: handle constant inputs in
 `LongestIncreasingSubsequence::findLISLen' (#5160)

fix: handle constant inputs in `LongestIncreasingSubsequence::findLISLen`
---
 .../LongestIncreasingSubsequence.java         | 27 +++-------
 .../LongestIncreasingSubsequenceTests.java    | 49 +++++++++++++++++++
 2 files changed, 56 insertions(+), 20 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
index 9457f0bec7e1..83c31989123f 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.dynamicprogramming;
 
-import java.util.Scanner;
-
 /**
  * @author Afrizal Fikri (https://github.com/icalF)
  */
@@ -9,20 +7,6 @@ public final class LongestIncreasingSubsequence {
     private LongestIncreasingSubsequence() {
     }
 
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        int n = sc.nextInt();
-
-        int[] arr = new int[n];
-        for (int i = 0; i < n; i++) {
-            arr[i] = sc.nextInt();
-        }
-
-        System.out.println(LIS(arr));
-        System.out.println(findLISLen(arr));
-        sc.close();
-    }
-
     private static int upperBound(int[] ar, int l, int r, int key) {
         while (l < r - 1) {
             int m = (l + r) >>> 1;
@@ -36,7 +20,7 @@ private static int upperBound(int[] ar, int l, int r, int key) {
         return r;
     }
 
-    private static int LIS(int[] array) {
+    public static int LIS(int[] array) {
         int N = array.length;
         if (N == 0) {
             return 0;
@@ -73,14 +57,17 @@ else if (array[i] > tail[length - 1]) {
      */
     // A function for finding the length of the LIS algorithm in O(nlogn) complexity.
     public static int findLISLen(int[] a) {
-        int size = a.length;
+        final int size = a.length;
+        if (size == 0) {
+            return 0;
+        }
         int[] arr = new int[size];
         arr[0] = a[0];
         int lis = 1;
         for (int i = 1; i < size; i++) {
-            int index = binarySearchBetween(arr, lis, a[i]);
+            int index = binarySearchBetween(arr, lis - 1, a[i]);
             arr[index] = a[i];
-            if (index > lis) {
+            if (index == lis) {
                 lis++;
             }
         }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java b/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java
new file mode 100644
index 000000000000..ea7abed50d89
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java
@@ -0,0 +1,49 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class LongestIncreasingSubsequenceTests {
+    @FunctionalInterface
+    public interface IntArrayToInt {
+        int apply(int[] array);
+    }
+
+    @ParameterizedTest
+    @MethodSource("testCases")
+    public void testLongestIncreasingSubsequence(final int expected, final int[] input, final IntArrayToInt method) {
+        assertEquals(expected, method.apply(input));
+    }
+
+    private static Stream<Arguments> testCases() {
+        final Object[][] testData = {
+            {0, new int[] {}},
+            {1, new int[] {1}},
+            {1, new int[] {2, 2}},
+            {1, new int[] {3, 3, 3}},
+            {1, new int[] {4, 4, 4, 4}},
+            {1, new int[] {5, 5, 5, 5, 5}},
+            {2, new int[] {1, 2}},
+            {2, new int[] {1, 2, 2, 2, 2}},
+            {2, new int[] {1, 0, 2}},
+            {3, new int[] {1, 10, 2, 30}},
+            {3, new int[] {5, 8, 3, 7, 9, 1}},
+            {6, new int[] {0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15}},
+            {4, new int[] {10, 9, 2, 5, 3, 7, 101, 18}},
+            {4, new int[] {10, 10, 9, 9, 2, 2, 5, 5, 3, 3, 7, 7, 101, 101, 18, 18}},
+            {4, new int[] {0, 1, 0, 3, 2, 3}},
+            {2, new int[] {1, 1, 2, 2, 2}},
+            {3, new int[] {1, 1, 2, 2, 2, 3, 3, 3, 3}},
+        };
+
+        final List<IntArrayToInt> methods = Arrays.asList(LongestIncreasingSubsequence::LIS, LongestIncreasingSubsequence::findLISLen);
+
+        return Stream.of(testData).flatMap(input -> methods.stream().map(method -> Arguments.of(input[0], input[1], method)));
+    }
+}

From d77d9010a8586bdc1f7c338952fad8c4561f3eed Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 19 May 2024 14:36:16 +0200
Subject: [PATCH 0162/1338] style: enable compiler warnings and treat them as
 errors (#5165)

---
 pom.xml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/pom.xml b/pom.xml
index 96478c484837..1ba57f5702f6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -75,6 +75,15 @@
                 <configuration>
                     <source>17</source>
                     <target>17</target>
+                    <compilerArgs>
+                        <arg>-Xlint:all</arg>
+                        <arg>-Xlint:-auxiliaryclass</arg>
+                        <arg>-Xlint:-rawtypes</arg>
+                        <arg>-Xlint:-serial</arg>
+                        <arg>-Xlint:-try</arg>
+                        <arg>-Xlint:-unchecked</arg>
+                        <arg>-Werror</arg>
+                    </compilerArgs>
                 </configuration>
             </plugin>
             <plugin>

From 5ee98eeb48aae1b016780370e3164b6922ab8839 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 19 May 2024 20:57:07 +0200
Subject: [PATCH 0163/1338] chore: migrate to java 21 (#5163)

---
 .devcontainer/Dockerfile        |  4 ++--
 .devcontainer/devcontainer.json |  2 +-
 .github/workflows/build.yml     |  4 ++--
 .github/workflows/codeql.yml    |  4 ++--
 .gitpod.dockerfile              |  2 +-
 pom.xml                         | 10 ++++++----
 6 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index 7b319b78d4d7..bcea8e797ffb 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -1,8 +1,8 @@
 # See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.238.0/containers/java/.devcontainer/base.Dockerfile
 
 # [Choice] Java version (use -bullseye variants on local arm64/Apple Silicon): 11, 17, 11-bullseye, 17-bullseye, 11-buster, 17-buster
-ARG VARIANT="17-bullseye"
-FROM mcr.microsoft.com/vscode/devcontainers/java:0-${VARIANT}
+ARG VARIANT="21-bullseye"
+FROM mcr.microsoft.com/vscode/devcontainers/java:1.1.0-${VARIANT}
 
 # [Option] Install Maven
 ARG INSTALL_MAVEN="false"
diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index 3994bec79ef8..fdc7cdbd25f9 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -8,7 +8,7 @@
 			// Update the VARIANT arg to pick a Java version: 11, 17
 			// Append -bullseye or -buster to pin to an OS version.
 			// Use the -bullseye variants on local arm64/Apple Silicon.
-			"VARIANT": "17-bullseye",
+			"VARIANT": "21-bullseye",
 			// Options
 			"INSTALL_MAVEN": "true",
 			"INSTALL_GRADLE": "true",
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index faf5dd6aa9bb..14a4ce5fe0f5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -6,10 +6,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - name: Set up JDK 17
+      - name: Set up JDK
         uses: actions/setup-java@v4
         with:
-          java-version: 17
+          java-version: 21
           distribution: 'adopt'
       - name: Build with Maven
         run: mvn --batch-mode --update-snapshots verify
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index f447eb954550..ff76b1af452a 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -26,10 +26,10 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
 
-      - name: Set up JDK 17
+      - name: Set up JDK
         uses: actions/setup-java@v4
         with:
-          java-version: 17
+          java-version: 21
           distribution: 'adopt'
 
       - name: Initialize CodeQL
diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 1f0020db1f0a..0bba1827bc86 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-17:2024-05-13-09-12-40
+FROM gitpod/workspace-java-21:2024-05-15-13-36-34
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 
diff --git a/pom.xml b/pom.xml
index 1ba57f5702f6..2c2f640d5e0f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -10,8 +10,8 @@
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <maven.compiler.source>17</maven.compiler.source>
-        <maven.compiler.target>17</maven.compiler.target>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
         <assertj.version>3.25.3</assertj.version>
     </properties>
 
@@ -73,8 +73,8 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.13.0</version>
                 <configuration>
-                    <source>17</source>
-                    <target>17</target>
+                    <source>21</source>
+                    <target>21</target>
                     <compilerArgs>
                         <arg>-Xlint:all</arg>
                         <arg>-Xlint:-auxiliaryclass</arg>
@@ -82,6 +82,8 @@
                         <arg>-Xlint:-serial</arg>
                         <arg>-Xlint:-try</arg>
                         <arg>-Xlint:-unchecked</arg>
+                        <arg>-Xlint:-lossy-conversions</arg>
+                        <arg>-Xlint:-this-escape</arg>
                         <arg>-Werror</arg>
                     </compilerArgs>
                 </configuration>

From 8466219685e0f98b8c71b21dc8107e4641fec5a8 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 20 May 2024 17:09:31 +0200
Subject: [PATCH 0164/1338] style: do not suppress `serial` (#5168)

---
 pom.xml                                                  | 1 -
 .../java/com/thealgorithms/sorts/TopologicalSort.java    | 9 +--------
 .../com/thealgorithms/sorts/TopologicalSortTest.java     | 3 +--
 3 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/pom.xml b/pom.xml
index 2c2f640d5e0f..ead4fb6dd0f0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -79,7 +79,6 @@
                         <arg>-Xlint:all</arg>
                         <arg>-Xlint:-auxiliaryclass</arg>
                         <arg>-Xlint:-rawtypes</arg>
-                        <arg>-Xlint:-serial</arg>
                         <arg>-Xlint:-try</arg>
                         <arg>-Xlint:-unchecked</arg>
                         <arg>-Xlint:-lossy-conversions</arg>
diff --git a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
index ce664b0197fc..dd3a763bb197 100644
--- a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
@@ -73,13 +73,6 @@ public void addEdge(String label, String... next) {
         }
     }
 
-    static class BackEdgeException extends RuntimeException {
-
-        BackEdgeException(String backEdge) {
-            super("This graph contains a cycle. No linear ordering is possible. " + backEdge);
-        }
-    }
-
     /*
      * Depth First Search
      *
@@ -131,7 +124,7 @@ private static String sort(Graph graph, Vertex u, LinkedList<String> list) {
                  *
                  * In many cases, we will not know u.f, but v.color denotes the type of edge
                  * */
-                throw new BackEdgeException("Back edge: " + u.label + " -> " + label);
+                throw new RuntimeException("This graph contains a cycle. No linear ordering is possible. Back edge: " + u.label + " -> " + label);
             }
         });
         u.color = Color.BLACK;
diff --git a/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java b/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
index 9fb0fc06a002..de115b458fe7 100644
--- a/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
@@ -4,7 +4,6 @@
 import static org.junit.jupiter.api.Assertions.assertIterableEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import com.thealgorithms.sorts.TopologicalSort.BackEdgeException;
 import com.thealgorithms.sorts.TopologicalSort.Graph;
 import java.util.LinkedList;
 import org.junit.jupiter.api.Test;
@@ -55,7 +54,7 @@ public void failureTest() {
         graph.addEdge("6", "2");
         graph.addEdge("7", "");
         graph.addEdge("8", "");
-        Exception exception = assertThrows(BackEdgeException.class, () -> TopologicalSort.sort(graph));
+        Exception exception = assertThrows(RuntimeException.class, () -> TopologicalSort.sort(graph));
         String expected = "This graph contains a cycle. No linear ordering is possible. "
             + "Back edge: 6 -> 2";
         assertEquals(exception.getMessage(), expected);

From 324969fc4eb33ed57a5552c54b56b6a578f2ba6b Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 20 May 2024 18:06:52 +0200
Subject: [PATCH 0165/1338] style: enable `OverrideBothEqualsAndHashcode` like
 checks (#5159)

---
 pmd-exclude.properties | 1 -
 spotbugs-exclude.xml   | 3 ---
 2 files changed, 4 deletions(-)

diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index 8722f126f6d5..400863992ed0 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -25,7 +25,6 @@ com.thealgorithms.datastructures.queues.PriorityQueue=UselessParentheses
 com.thealgorithms.datastructures.stacks.NodeStack=UnnecessaryFullyQualifiedName,UnusedFormalParameter
 com.thealgorithms.datastructures.stacks.StackArray=UselessParentheses
 com.thealgorithms.datastructures.trees.CheckBinaryTreeIsValidBST=UselessParentheses
-com.thealgorithms.datastructures.trees.Point=OverrideBothEqualsAndHashcode
 com.thealgorithms.datastructures.trees.SegmentTree=UselessParentheses
 com.thealgorithms.devutils.nodes.LargeTreeNode=UselessParentheses
 com.thealgorithms.devutils.nodes.SimpleNode=UselessParentheses
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 1f53feafb3be..ffccae635f3b 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -80,9 +80,6 @@
     <Match>
         <Bug pattern="SS_SHOULD_BE_STATIC" />
     </Match>
-    <Match>
-        <Bug pattern="HE_EQUALS_USE_HASHCODE" />
-    </Match>
     <Match>
         <Bug pattern="IT_NO_SUCH_ELEMENT" />
     </Match>

From 8be8b953ab677634dd0c548badbde36c0e17202b Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 20 May 2024 18:09:23 +0200
Subject: [PATCH 0166/1338] style: do not suppress `this-escape` (#5166)

---
 pom.xml                                                         | 1 -
 src/main/java/com/thealgorithms/ciphers/RSA.java                | 2 +-
 .../java/com/thealgorithms/datastructures/heaps/MaxHeap.java    | 2 +-
 .../java/com/thealgorithms/datastructures/heaps/MinHeap.java    | 2 +-
 .../thealgorithms/datastructures/lists/DoublyLinkedList.java    | 2 +-
 .../com/thealgorithms/datastructures/trees/SegmentTree.java     | 2 +-
 6 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/pom.xml b/pom.xml
index ead4fb6dd0f0..21b5ec350917 100644
--- a/pom.xml
+++ b/pom.xml
@@ -82,7 +82,6 @@
                         <arg>-Xlint:-try</arg>
                         <arg>-Xlint:-unchecked</arg>
                         <arg>-Xlint:-lossy-conversions</arg>
-                        <arg>-Xlint:-this-escape</arg>
                         <arg>-Werror</arg>
                     </compilerArgs>
                 </configuration>
diff --git a/src/main/java/com/thealgorithms/ciphers/RSA.java b/src/main/java/com/thealgorithms/ciphers/RSA.java
index aea15c3554c0..f50e501e68c8 100644
--- a/src/main/java/com/thealgorithms/ciphers/RSA.java
+++ b/src/main/java/com/thealgorithms/ciphers/RSA.java
@@ -47,7 +47,7 @@ public synchronized BigInteger decrypt(BigInteger encryptedMessage) {
     /**
      * Generate a new public and private key set.
      */
-    public synchronized void generateKeys(int bits) {
+    public final synchronized void generateKeys(int bits) {
         SecureRandom r = new SecureRandom();
         BigInteger p = new BigInteger(bits / 2, 100, r);
         BigInteger q = new BigInteger(bits / 2, 100, r);
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
index 4edf02679eb4..9a584da0411c 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
@@ -91,7 +91,7 @@ private HeapElement extractMax() {
     }
 
     @Override
-    public void insertElement(HeapElement element) {
+    public final void insertElement(HeapElement element) {
         maxHeap.add(element);
         toggleUp(maxHeap.size());
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
index f220fe492399..f7ff0ec5a73d 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
@@ -85,7 +85,7 @@ private HeapElement extractMin() {
     }
 
     @Override
-    public void insertElement(HeapElement element) {
+    public final void insertElement(HeapElement element) {
         minHeap.add(element);
         toggleUp(minHeap.size());
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java
index 7f10d7cd93a6..58898ddc0fcf 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java
@@ -13,7 +13,7 @@
  *
  * @author Unknown
  */
-public class DoublyLinkedList {
+public final class DoublyLinkedList {
 
     /**
      * Head refers to the front of the list
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
index 295628334516..55efe30adcd8 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
@@ -19,7 +19,7 @@ public SegmentTree(int n, int[] arr) {
     }
 
     /* A function which will create the segment tree*/
-    public int constructTree(int[] arr, int start, int end, int index) {
+    public final int constructTree(int[] arr, int start, int end, int index) {
         if (start == end) {
             this.seg_t[index] = arr[start];
             return arr[start];

From 160742104d3aea0ba28627bfd2b990fcc3277deb Mon Sep 17 00:00:00 2001
From: Godwill Christopher <chrisgodswill115@gmail.com>
Date: Fri, 24 May 2024 05:08:37 -0600
Subject: [PATCH 0167/1338] Enabled LocalFinalVariableName in Checkstyle
 (#5172)

---
 checkstyle.xml                                           | 2 +-
 src/main/java/com/thealgorithms/maths/DudeneyNumber.java | 6 +++---
 src/main/java/com/thealgorithms/sorts/SimpleSort.java    | 6 +++---
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index ce584392b089..7a91d52106a9 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -109,7 +109,7 @@
     <!-- Checks for Naming Conventions.                  -->
     <!-- See https://checkstyle.org/checks/naming/index.html -->
     <module name="ConstantName"/>
-    <!-- TODO <module name="LocalFinalVariableName"/> -->
+    <module name="LocalFinalVariableName"/>
     <!-- TODO <module name="LocalVariableName"/> -->
     <!-- TODO <module name="MemberName"/> -->
     <!-- TODO <module name="MethodName"/> -->
diff --git a/src/main/java/com/thealgorithms/maths/DudeneyNumber.java b/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
index 88e008cf8a08..acf1e55d49c8 100644
--- a/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
@@ -16,13 +16,13 @@ public static boolean isDudeney(final int n) {
             throw new IllegalArgumentException("Input must me positive.");
         }
         // Calculating Cube Root
-        final int cube_root = (int) Math.round(Math.pow(n, 1.0 / 3.0));
+        final int cubeRoot = (int) Math.round(Math.pow(n, 1.0 / 3.0));
         // If the number is not a perfect cube the method returns false.
-        if (cube_root * cube_root * cube_root != n) {
+        if (cubeRoot * cubeRoot * cubeRoot != n) {
             return false;
         }
 
         // If the cube root of the number is not equal to the sum of its digits, we return false.
-        return cube_root == SumOfDigits.sumOfDigits(n);
+        return cubeRoot == SumOfDigits.sumOfDigits(n);
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/SimpleSort.java b/src/main/java/com/thealgorithms/sorts/SimpleSort.java
index e68b9a87acb2..7aab7c784b92 100644
--- a/src/main/java/com/thealgorithms/sorts/SimpleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SimpleSort.java
@@ -4,10 +4,10 @@ public class SimpleSort implements SortAlgorithm {
 
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
-        final int LENGTH = array.length;
+        final int length = array.length;
 
-        for (int i = 0; i < LENGTH; i++) {
-            for (int j = i + 1; j < LENGTH; j++) {
+        for (int i = 0; i < length; i++) {
+            for (int j = i + 1; j < length; j++) {
                 if (SortUtils.less(array[j], array[i])) {
                     T element = array[j];
                     array[j] = array[i];

From 44ce6e7b0d470c06c3a7730d113a28a6e5630391 Mon Sep 17 00:00:00 2001
From: vaibhav9t1 <115015082+vaibhav9t1@users.noreply.github.com>
Date: Sat, 25 May 2024 19:39:14 +0530
Subject: [PATCH 0168/1338] style: enable `StaticVariableName` in checkstyle
 (#5173)

* style: enable StaticVariableName in checkstyle

* Refractored: enable StaticVariableName in checkstyle

* style: mark more variables as `final`

---------

Co-authored-by: vaibhav <vaibhav.waghmare@techprescient.com>
Co-authored-by: vil02 <vil02@o2.pl>
---
 checkstyle.xml                                |  2 +-
 .../java/com/thealgorithms/ciphers/DES.java   | 52 +++++++++----------
 .../dynamicprogramming/FordFulkerson.java     | 16 +++---
 .../com/thealgorithms/others/RabinKarp.java   |  8 +--
 .../others/StringMatchFiniteAutomata.java     | 16 +++---
 5 files changed, 47 insertions(+), 47 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 7a91d52106a9..03bcdb1d3855 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -115,7 +115,7 @@
     <!-- TODO <module name="MethodName"/> -->
     <module name="PackageName"/>
     <!-- TODO <module name="ParameterName"/> -->
-    <!-- TODO <module name="StaticVariableName"/> -->
+    <module name="StaticVariableName"/>
     <!-- TODO <module name="TypeName"/> -->
 
     <!-- Checks for imports                              -->
diff --git a/src/main/java/com/thealgorithms/ciphers/DES.java b/src/main/java/com/thealgorithms/ciphers/DES.java
index 8e44f09131ae..d0a24f1e7c64 100644
--- a/src/main/java/com/thealgorithms/ciphers/DES.java
+++ b/src/main/java/com/thealgorithms/ciphers/DES.java
@@ -8,7 +8,7 @@
 public class DES {
 
     private String key;
-    private String[] subKeys;
+    private final String[] subKeys;
 
     private void sanitize(String key) {
         int length = key.length();
@@ -32,48 +32,48 @@ public void setKey(String key) {
         this.key = key;
     }
 
-    // Permutation table to convert initial 64 bit key to 56 bit key
-    private static int[] PC1 = {57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4};
+    // Permutation table to convert initial 64-bit key to 56 bit key
+    private static final int[] PC1 = {57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4};
 
     // Lookup table used to shift the initial key, in order to generate the subkeys
-    private static int[] KEY_SHIFTS = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1};
+    private static final int[] KEY_SHIFTS = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1};
 
     // Table to convert the 56 bit subkeys to 48 bit subkeys
-    private static int[] PC2 = {14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2, 41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32};
+    private static final int[] PC2 = {14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2, 41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32};
 
-    // Initial permutatation of each 64 but message block
-    private static int[] IP = {58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7};
+    // Initial permutation of each 64 but message block
+    private static final int[] IP = {58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7};
 
     // Expansion table to convert right half of message blocks from 32 bits to 48 bits
-    private static int[] expansion = {32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1};
+    private static final int[] EXPANSION = {32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1};
 
     // The eight substitution boxes are defined below
-    private static int[][] s1 = {{14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7}, {0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8}, {4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0}, {15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13}};
+    private static final int[][] S1 = {{14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7}, {0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8}, {4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0}, {15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13}};
 
-    private static int[][] s2 = {{15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10}, {3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5}, {0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15}, {13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9}};
+    private static final int[][] S2 = {{15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10}, {3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5}, {0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15}, {13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9}};
 
-    private static int[][] s3 = {{10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8}, {13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1}, {13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7}, {1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12}};
+    private static final int[][] S3 = {{10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8}, {13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1}, {13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7}, {1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12}};
 
-    private static int[][] s4 = {{7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15}, {13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9}, {10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4}, {3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14}};
+    private static final int[][] S4 = {{7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15}, {13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9}, {10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4}, {3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14}};
 
-    private static int[][] s5 = {{2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9}, {14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6}, {4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14}, {11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3}};
+    private static final int[][] S5 = {{2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9}, {14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6}, {4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14}, {11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3}};
 
-    private static int[][] s6 = {{12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11}, {10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8}, {9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6}, {4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13}};
+    private static final int[][] S6 = {{12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11}, {10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8}, {9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6}, {4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13}};
 
-    private static int[][] s7 = {{4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1}, {13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6}, {1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2}, {6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12}};
+    private static final int[][] S7 = {{4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1}, {13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6}, {1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2}, {6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12}};
 
-    private static int[][] s8 = {{13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7}, {1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2}, {7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8}, {2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11}};
+    private static final int[][] S8 = {{13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7}, {1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2}, {7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8}, {2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11}};
 
-    private static int[][][] s = {s1, s2, s3, s4, s5, s6, s7, s8};
+    private static final int[][][] S = {S1, S2, S3, S4, S5, S6, S7, S8};
 
-    // Permutation table, used in the feistel function post s-box usage
-    static int[] permutation = {16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25};
+    // Permutation table, used in the Feistel function post s-box usage
+    static final int[] PERMUTATION = {16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25};
 
     // Table used for final inversion of the message box after 16 rounds of Feistel Function
-    static int[] IPinverse = {40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25};
+    static final int[] IP_INVERSE = {40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25};
 
     private String[] getSubkeys(String originalKey) {
-        StringBuilder permutedKey = new StringBuilder(); // Initial permutation of keys via PC1
+        StringBuilder permutedKey = new StringBuilder(); // Initial permutation of keys via pc1
         int i, j;
         for (i = 0; i < 56; i++) {
             permutedKey.append(originalKey.charAt(PC1[i] - 1));
@@ -91,7 +91,7 @@ private String[] getSubkeys(String originalKey) {
             D0 = Dn;
         }
 
-        // Let us shrink the keys to 48 bits (well, characters here) using PC2
+        // Let us shrink the keys to 48 bits (well, characters here) using pc2
         for (i = 0; i < 16; i++) {
             String key = subKeys[i];
             permutedKey.setLength(0);
@@ -137,7 +137,7 @@ private String feistel(String messageBlock, String key) {
         int i;
         StringBuilder expandedKey = new StringBuilder();
         for (i = 0; i < 48; i++) {
-            expandedKey.append(messageBlock.charAt(expansion[i] - 1));
+            expandedKey.append(messageBlock.charAt(EXPANSION[i] - 1));
         }
         String mixedKey = XOR(expandedKey.toString(), key);
         StringBuilder substitutedString = new StringBuilder();
@@ -147,13 +147,13 @@ private String feistel(String messageBlock, String key) {
             String block = mixedKey.substring(i, i + 6);
             int row = (block.charAt(0) - 48) * 2 + (block.charAt(5) - 48);
             int col = (block.charAt(1) - 48) * 8 + (block.charAt(2) - 48) * 4 + (block.charAt(3) - 48) * 2 + (block.charAt(4) - 48);
-            String substitutedBlock = pad(Integer.toBinaryString(s[i / 6][row][col]), 4);
+            String substitutedBlock = pad(Integer.toBinaryString(S[i / 6][row][col]), 4);
             substitutedString.append(substitutedBlock);
         }
 
         StringBuilder permutedString = new StringBuilder();
         for (i = 0; i < 32; i++) {
-            permutedString.append(substitutedString.charAt(permutation[i] - 1));
+            permutedString.append(substitutedString.charAt(PERMUTATION[i] - 1));
         }
 
         return permutedString.toString();
@@ -178,7 +178,7 @@ private String encryptBlock(String message, String[] keys) {
         String combinedBlock = R0 + L0; // Reverse the 16th block
         permutedMessage.setLength(0);
         for (i = 0; i < 64; i++) {
-            permutedMessage.append(combinedBlock.charAt(IPinverse[i] - 1));
+            permutedMessage.append(combinedBlock.charAt(IP_INVERSE[i] - 1));
         }
         return permutedMessage.toString();
     }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java b/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
index 9e1516ec3570..b57dec97b88d 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
@@ -10,13 +10,13 @@ private FordFulkerson() {
 
     static final int INF = 987654321;
     // edges
-    static int V;
+    static int vertexCount;
     static int[][] capacity, flow;
 
     public static void main(String[] args) {
-        System.out.println("V : 6");
-        V = 6;
-        capacity = new int[V][V];
+        System.out.println("Vertex Count : 6");
+        vertexCount = 6;
+        capacity = new int[vertexCount][vertexCount];
 
         capacity[0][1] = 12;
         capacity[0][3] = 13;
@@ -32,11 +32,11 @@ public static void main(String[] args) {
     }
 
     private static int networkFlow(int source, int sink) {
-        flow = new int[V][V];
+        flow = new int[vertexCount][vertexCount];
         int totalFlow = 0;
         while (true) {
-            Vector<Integer> parent = new Vector<>(V);
-            for (int i = 0; i < V; i++) {
+            Vector<Integer> parent = new Vector<>(vertexCount);
+            for (int i = 0; i < vertexCount; i++) {
                 parent.add(-1);
             }
             Queue<Integer> q = new LinkedList<>();
@@ -45,7 +45,7 @@ private static int networkFlow(int source, int sink) {
             while (!q.isEmpty() && parent.get(sink) == -1) {
                 int here = q.peek();
                 q.poll();
-                for (int there = 0; there < V; ++there) {
+                for (int there = 0; there < vertexCount; ++there) {
                     if (capacity[here][there] - flow[here][there] > 0 && parent.get(there) == -1) {
                         q.add(there);
                         parent.set(there, here);
diff --git a/src/main/java/com/thealgorithms/others/RabinKarp.java b/src/main/java/com/thealgorithms/others/RabinKarp.java
index 8188a1a702d0..f8ca33becad3 100644
--- a/src/main/java/com/thealgorithms/others/RabinKarp.java
+++ b/src/main/java/com/thealgorithms/others/RabinKarp.java
@@ -11,15 +11,15 @@ public final class RabinKarp {
     private RabinKarp() {
     }
 
-    public static Scanner SCANNER = null;
+    public static Scanner scanner = null;
     public static final int ALPHABET_SIZE = 256;
 
     public static void main(String[] args) {
-        SCANNER = new Scanner(System.in);
+        scanner = new Scanner(System.in);
         System.out.println("Enter String");
-        String text = SCANNER.nextLine();
+        String text = scanner.nextLine();
         System.out.println("Enter pattern");
-        String pattern = SCANNER.nextLine();
+        String pattern = scanner.nextLine();
 
         int q = 101;
         searchPat(text, pattern, q);
diff --git a/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java b/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
index 15148de176b1..22979e59b555 100644
--- a/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
+++ b/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
@@ -5,13 +5,13 @@
  */
 import java.util.Scanner;
 
-// An implementaion of string matching using finite automata
+// An implementation of string matching using finite automata
 public final class StringMatchFiniteAutomata {
     private StringMatchFiniteAutomata() {
     }
 
     public static final int CHARS = 256;
-    public static int[][] FA;
+    public static int[][] fa;
     public static Scanner scanner = null;
 
     public static void main(String[] args) {
@@ -30,13 +30,13 @@ public static void searchPat(String text, String pat) {
         int m = pat.length();
         int n = text.length();
 
-        FA = new int[m + 1][CHARS];
+        fa = new int[m + 1][CHARS];
 
-        computeFA(pat, m, FA);
+        computeFA(pat, m, fa);
 
         int state = 0;
         for (int i = 0; i < n; i++) {
-            state = FA[state][text.charAt(i)];
+            state = fa[state][text.charAt(i)];
 
             if (state == m) {
                 System.out.println("Pattern found at index " + (i - m + 1));
@@ -44,11 +44,11 @@ public static void searchPat(String text, String pat) {
         }
     }
 
-    // Computes finite automata for the partern
-    public static void computeFA(String pat, int m, int[][] FA) {
+    // Computes finite automata for the pattern
+    public static void computeFA(String pat, int m, int[][] fa) {
         for (int state = 0; state <= m; ++state) {
             for (int x = 0; x < CHARS; ++x) {
-                FA[state][x] = getNextState(pat, m, state, x);
+                fa[state][x] = getNextState(pat, m, state, x);
             }
         }
     }

From 9eaa2bb7562fc6e58f9a61ad6a6679e87bb8a174 Mon Sep 17 00:00:00 2001
From: vaibhav9t1 <115015082+vaibhav9t1@users.noreply.github.com>
Date: Sat, 25 May 2024 23:48:27 +0530
Subject: [PATCH 0169/1338] style: enable `MultipleVariableDeclarations` in
 checkstyle (#5175)

Co-authored-by: vaibhav <vaibhav.waghmare@techprescient.com>
---
 checkstyle.xml                                |  2 +-
 .../thealgorithms/backtracking/PowerSum.java  |  3 ++-
 .../com/thealgorithms/ciphers/Blowfish.java   |  3 ++-
 .../java/com/thealgorithms/ciphers/DES.java   | 23 +++++++++++++------
 .../com/thealgorithms/ciphers/HillCipher.java | 11 ++++++---
 .../conversions/AnyBaseToAnyBase.java         |  6 +++--
 .../thealgorithms/conversions/AnytoAny.java   |  4 +++-
 .../conversions/BinaryToDecimal.java          |  5 +++-
 .../conversions/BinaryToOctal.java            |  3 ++-
 .../conversions/DecimalToBinary.java          | 10 ++++++--
 .../conversions/DecimalToOctal.java           |  6 ++++-
 .../thealgorithms/conversions/HexToOct.java   |  3 ++-
 .../datastructures/graphs/BellmanFord.java    | 21 +++++++++++++----
 .../graphs/ConnectedComponent.java            |  6 +++--
 .../datastructures/graphs/Cycles.java         |  6 +++--
 .../graphs/DIJSKSTRAS_ALGORITHM.java          |  3 ++-
 .../datastructures/graphs/Graphs.java         |  3 ++-
 .../graphs/HamiltonianCycle.java              |  3 ++-
 .../datastructures/graphs/PrimMST.java        |  3 ++-
 .../hashmap/hashing/HashMapCuckooHashing.java |  6 +++--
 .../datastructures/hashmap/hashing/Main.java  |  3 ++-
 .../hashmap/hashing/MainCuckooHashing.java    |  3 ++-
 .../datastructures/heaps/LeftistHeap.java     |  8 ++++---
 .../lists/SinglyLinkedList.java               |  6 +++--
 .../datastructures/trees/AVLTree.java         |  4 +++-
 .../datastructures/trees/LCA.java             |  9 +++++---
 .../datastructures/trees/LazySegmentTree.java |  6 +++--
 .../trees/PrintTopViewofTree.java             |  3 ++-
 .../datastructures/trees/RedBlackBST.java     |  7 ++++--
 .../datastructures/trees/TreeRandomNode.java  |  3 ++-
 .../trees/VerticalOrderTraversal.java         |  3 ++-
 .../BinaryExponentiation.java                 |  3 ++-
 .../dynamicprogramming/EditDistance.java      |  3 ++-
 .../dynamicprogramming/EggDropping.java       |  6 +++--
 .../dynamicprogramming/Fibonacci.java         |  4 +++-
 .../dynamicprogramming/FordFulkerson.java     |  3 ++-
 .../dynamicprogramming/KadaneAlgorithm.java   |  3 ++-
 .../LongestCommonSubsequence.java             |  3 ++-
 .../LongestPalindromicSubstring.java          |  3 ++-
 .../PalindromicPartitioning.java              |  4 +++-
 .../ShortestCommonSupersequenceLength.java    |  3 ++-
 .../dynamicprogramming/Tribonacci.java        |  4 +++-
 .../com/thealgorithms/io/BufferedReader.java  |  3 ++-
 .../maths/AutomorphicNumber.java              |  3 ++-
 .../maths/DeterminantOfMatrix.java            |  5 +++-
 .../java/com/thealgorithms/maths/FFT.java     |  3 ++-
 .../thealgorithms/maths/FindKthNumber.java    |  3 ++-
 .../com/thealgorithms/maths/Gaussian.java     |  6 +++--
 .../com/thealgorithms/maths/KeithNumber.java  |  8 ++++---
 .../maths/LeastCommonMultiple.java            |  3 ++-
 .../maths/NonRepeatingElement.java            |  6 +++--
 .../com/thealgorithms/maths/PollardRho.java   |  4 +++-
 .../com/thealgorithms/maths/PrimeCheck.java   |  3 ++-
 .../thealgorithms/misc/matrixTranspose.java   |  5 +++-
 .../others/BankersAlgorithm.java              |  3 ++-
 .../com/thealgorithms/others/Dijkstra.java    |  6 +++--
 .../thealgorithms/others/FibbonaciSeries.java |  3 ++-
 .../thealgorithms/others/FloydTriangle.java   |  3 ++-
 .../thealgorithms/others/GuassLegendre.java   |  5 +++-
 .../thealgorithms/others/KochSnowflake.java   |  3 ++-
 .../thealgorithms/others/Krishnamurthy.java   |  7 ++++--
 .../others/LinearCongruentialGenerator.java   |  5 +++-
 .../others/MiniMaxAlgorithm.java              |  4 +++-
 .../com/thealgorithms/others/PageRank.java    |  4 +++-
 .../others/RotateMatrixBy90Degrees.java       |  3 ++-
 .../thealgorithms/others/SkylineProblem.java  |  3 ++-
 .../scheduling/SJFScheduling.java             | 19 +++++++++++----
 .../scheduling/SRTFScheduling.java            |  3 ++-
 .../searches/BinarySearch2dArray.java         |  7 ++++--
 .../searches/InterpolationSearch.java         |  3 ++-
 .../searches/IterativeBinarySearch.java       |  5 +++-
 .../searches/LinearSearchThread.java          |  3 ++-
 .../searches/SaddlebackSearch.java            |  5 +++-
 .../sorts/CocktailShakerSort.java             |  3 ++-
 .../java/com/thealgorithms/sorts/DNFSort.java |  3 ++-
 .../com/thealgorithms/sorts/LinkListSort.java | 19 +++++++++++----
 .../com/thealgorithms/sorts/MergeSort.java    |  3 ++-
 .../java/com/thealgorithms/sorts/TimSort.java |  3 ++-
 .../stacks/LargestRectangle.java              |  3 ++-
 .../thealgorithms/stacks/PostfixToInfix.java  |  3 ++-
 .../strings/longestNonRepeativeSubstring.java |  4 +++-
 .../strings/zigZagPattern/zigZagPattern.java  |  9 ++++++--
 82 files changed, 299 insertions(+), 121 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 03bcdb1d3855..b27e775f0f89 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -167,7 +167,7 @@
     <module name="InnerAssignment"/>
     <!-- TODO <module name="MagicNumber"/> -->
     <!-- TODO <module name="MissingSwitchDefault"/> -->
-    <!-- TODO <module name="MultipleVariableDeclarations"/> -->
+    <module name="MultipleVariableDeclarations"/>
     <module name="SimplifyBooleanExpression"/>
     <module name="SimplifyBooleanReturn"/>
 
diff --git a/src/main/java/com/thealgorithms/backtracking/PowerSum.java b/src/main/java/com/thealgorithms/backtracking/PowerSum.java
index 72af17d48bd4..29e37a1ddde8 100644
--- a/src/main/java/com/thealgorithms/backtracking/PowerSum.java
+++ b/src/main/java/com/thealgorithms/backtracking/PowerSum.java
@@ -8,7 +8,8 @@
  */
 public class PowerSum {
 
-    private int count = 0, sum = 0;
+    private int count = 0;
+    private int sum = 0;
 
     public int powSum(int N, int X) {
         Sum(N, X, 1);
diff --git a/src/main/java/com/thealgorithms/ciphers/Blowfish.java b/src/main/java/com/thealgorithms/ciphers/Blowfish.java
index fc7c5d04fcb0..d0e947206e5f 100644
--- a/src/main/java/com/thealgorithms/ciphers/Blowfish.java
+++ b/src/main/java/com/thealgorithms/ciphers/Blowfish.java
@@ -1175,7 +1175,8 @@ private void keyGenerate(String key) {
 
     // round function
     private String round(int time, String plainText) {
-        String left, right;
+        String left;
+        String right;
         left = plainText.substring(0, 8);
         right = plainText.substring(8, 16);
         left = xor(left, P[time]);
diff --git a/src/main/java/com/thealgorithms/ciphers/DES.java b/src/main/java/com/thealgorithms/ciphers/DES.java
index d0a24f1e7c64..d601b61dcd34 100644
--- a/src/main/java/com/thealgorithms/ciphers/DES.java
+++ b/src/main/java/com/thealgorithms/ciphers/DES.java
@@ -74,13 +74,15 @@ public void setKey(String key) {
 
     private String[] getSubkeys(String originalKey) {
         StringBuilder permutedKey = new StringBuilder(); // Initial permutation of keys via pc1
-        int i, j;
+        int i;
+        int j;
         for (i = 0; i < 56; i++) {
             permutedKey.append(originalKey.charAt(PC1[i] - 1));
         }
         String[] subKeys = new String[16];
         String initialPermutedKey = permutedKey.toString();
-        String C0 = initialPermutedKey.substring(0, 28), D0 = initialPermutedKey.substring(28);
+        String C0 = initialPermutedKey.substring(0, 28);
+        String D0 = initialPermutedKey.substring(28);
 
         // We will now operate on the left and right halves of the permutedKey
         for (i = 0; i < 16; i++) {
@@ -105,7 +107,8 @@ private String[] getSubkeys(String originalKey) {
     }
 
     private String XOR(String a, String b) {
-        int i, l = a.length();
+        int i;
+        int l = a.length();
         StringBuilder xor = new StringBuilder();
         for (i = 0; i < l; i++) {
             int firstBit = a.charAt(i) - 48; // 48 is '0' in ascii
@@ -116,7 +119,8 @@ private String XOR(String a, String b) {
     }
 
     private String createPaddedString(String s, int desiredLength, char pad) {
-        int i, l = s.length();
+        int i;
+        int l = s.length();
         StringBuilder paddedString = new StringBuilder();
         int diff = desiredLength - l;
         for (i = 0; i < diff; i++) {
@@ -165,7 +169,8 @@ private String encryptBlock(String message, String[] keys) {
         for (i = 0; i < 64; i++) {
             permutedMessage.append(message.charAt(IP[i] - 1));
         }
-        String L0 = permutedMessage.substring(0, 32), R0 = permutedMessage.substring(32);
+        String L0 = permutedMessage.substring(0, 32);
+        String R0 = permutedMessage.substring(32);
 
         // Iterate 16 times
         for (i = 0; i < 16; i++) {
@@ -198,7 +203,9 @@ private String decryptBlock(String message, String[] keys) {
      */
     public String encrypt(String message) {
         StringBuilder encryptedMessage = new StringBuilder();
-        int l = message.length(), i, j;
+        int l = message.length();
+        int i;
+        int j;
         if (l % 8 != 0) {
             int desiredLength = (l / 8 + 1) * 8;
             l = desiredLength;
@@ -223,7 +230,9 @@ public String encrypt(String message) {
      */
     public String decrypt(String message) {
         StringBuilder decryptedMessage = new StringBuilder();
-        int l = message.length(), i, j;
+        int l = message.length();
+        int i;
+        int j;
         if (l % 64 != 0) {
             throw new IllegalArgumentException("Encrypted message should be a multiple of 64 characters in length");
         }
diff --git a/src/main/java/com/thealgorithms/ciphers/HillCipher.java b/src/main/java/com/thealgorithms/ciphers/HillCipher.java
index 14b98b3cc2f8..0ef7bc82f00e 100644
--- a/src/main/java/com/thealgorithms/ciphers/HillCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/HillCipher.java
@@ -48,7 +48,8 @@ static void encrypt(String message) {
                 System.out.println(messageVector[i][0]);
                 j++;
             }
-            int x, i;
+            int x;
+            int i;
             for (i = 0; i < matrixSize; i++) {
                 cipherMatrix[i][0] = 0;
 
@@ -96,7 +97,8 @@ static void decrypt(String message) {
                 System.out.println(messageVector[i][0]);
                 j++;
             }
-            int x, i;
+            int x;
+            int i;
             for (i = 0; i < n; i++) {
                 plainMatrix[i][0] = 0;
 
@@ -115,7 +117,10 @@ static void decrypt(String message) {
 
     // Determinant calculator
     public static int determinant(int[][] a, int n) {
-        int det = 0, sign = 1, p = 0, q = 0;
+        int det = 0;
+        int sign = 1;
+        int p = 0;
+        int q = 0;
 
         if (n == 1) {
             det = a[0][0];
diff --git a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
index a5fc72c8bfb4..4bd9c74a1751 100644
--- a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
+++ b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
@@ -27,7 +27,8 @@ private AnyBaseToAnyBase() {
     public static void main(String[] args) {
         Scanner in = new Scanner(System.in);
         String n;
-        int b1, b2;
+        int b1;
+        int b2;
         while (true) {
             try {
                 System.out.print("Enter number: ");
@@ -132,7 +133,8 @@ public static String base2base(String n, int b1, int b2) {
         // Declare variables: decimal value of n,
         // character of base b1, character of base b2,
         // and the string that will be returned.
-        int decimalValue = 0, charB2;
+        int decimalValue = 0;
+        int charB2;
         char charB1;
         String output = "";
         // Go through every character of n
diff --git a/src/main/java/com/thealgorithms/conversions/AnytoAny.java b/src/main/java/com/thealgorithms/conversions/AnytoAny.java
index 609a81561b1b..801e493032e0 100644
--- a/src/main/java/com/thealgorithms/conversions/AnytoAny.java
+++ b/src/main/java/com/thealgorithms/conversions/AnytoAny.java
@@ -15,7 +15,9 @@ public static void main(String[] args) {
         int sn = scn.nextInt();
         int sb = scn.nextInt();
         int db = scn.nextInt();
-        int m = 1, dec = 0, dn = 0;
+        int m = 1;
+        int dec = 0;
+        int dn = 0;
         while (sn != 0) {
             dec = dec + (sn % 10) * m;
             m *= sb;
diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java b/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
index 57d49d7b17f8..67b815ab6466 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
@@ -10,7 +10,10 @@ private BinaryToDecimal() {
     }
 
     public static long binaryToDecimal(long binNum) {
-        long binCopy, d, s = 0, power = 0;
+        long binCopy;
+        long d;
+        long s = 0;
+        long power = 0;
         binCopy = binNum;
         while (binCopy != 0) {
             d = binCopy % 10;
diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java b/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java
index f171cdf69801..6fef090287ab 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java
@@ -32,7 +32,8 @@ public static void main(String[] args) {
      */
     public static String convertBinaryToOctal(int binary) {
         String octal = "";
-        int currBit = 0, j = 1;
+        int currBit = 0;
+        int j = 1;
         while (binary != 0) {
             int code3 = 0;
             for (int i = 0; i < 3; i++) {
diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java b/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java
index 329985a05fde..471724ff9966 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java
@@ -24,7 +24,10 @@ public static void main(String[] args) {
      * conventional algorithm.
      */
     public static void conventionalConversion() {
-        int n, b = 0, c = 0, d;
+        int n;
+        int b = 0;
+        int c = 0;
+        int d;
         Scanner input = new Scanner(System.in);
         System.out.printf("Conventional conversion.%n Enter the decimal number: ");
         n = input.nextInt();
@@ -42,7 +45,10 @@ public static void conventionalConversion() {
      * algorithm
      */
     public static void bitwiseConversion() {
-        int n, b = 0, c = 0, d;
+        int n;
+        int b = 0;
+        int c = 0;
+        int d;
         Scanner input = new Scanner(System.in);
         System.out.printf("Bitwise conversion.%n Enter the decimal number: ");
         n = input.nextInt();
diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java b/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java
index 1d0a6f1a1060..4bc3a6e7af8c 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java
@@ -18,7 +18,11 @@ private DecimalToOctal() {
     // enter in a decimal value to get Octal output
     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
-        int n, k, d, s = 0, c = 0;
+        int n;
+        int k;
+        int d;
+        int s = 0;
+        int c = 0;
         System.out.print("Decimal number: ");
         n = sc.nextInt();
         k = n;
diff --git a/src/main/java/com/thealgorithms/conversions/HexToOct.java b/src/main/java/com/thealgorithms/conversions/HexToOct.java
index b4994ae0f5fb..97a8be16b2e0 100644
--- a/src/main/java/com/thealgorithms/conversions/HexToOct.java
+++ b/src/main/java/com/thealgorithms/conversions/HexToOct.java
@@ -56,7 +56,8 @@ public static int decimal2octal(int q) {
      */
     public static void main(String[] args) {
         String hexadecnum;
-        int decnum, octalnum;
+        int decnum;
+        int octalnum;
         Scanner scan = new Scanner(System.in);
 
         System.out.print("Enter Hexadecimal Number : ");
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
index b4420b3e62d9..a84a3ceff6b6 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
@@ -11,7 +11,8 @@ class BellmanFord /*
                    */
 {
 
-    int vertex, edge;
+    int vertex;
+    int edge;
     private Edge[] edges;
     private int index = 0;
 
@@ -23,7 +24,8 @@ class BellmanFord /*
 
     class Edge {
 
-        int u, v;
+        int u;
+        int v;
         int w;
 
         /**
@@ -58,7 +60,14 @@ public static void main(String[] args) {
     public void go() { // shows distance to all vertices // Interactive run for understanding the
         try ( // class first time. Assumes source vertex is 0 and
             Scanner sc = new Scanner(System.in)) {
-            int i, v, e, u, ve, w, j, neg = 0;
+            int i;
+            int v;
+            int e;
+            int u;
+            int ve;
+            int w;
+            int j;
+            int neg = 0;
             System.out.println("Enter no. of vertices and edges please");
             v = sc.nextInt();
             e = sc.nextInt();
@@ -120,7 +129,11 @@ public void show(int source, int end,
         Edge[] arr) { // be created by using addEdge() method and passed by calling getEdgeArray()
                       // method // Just shows results of computation, if graph is passed to it. The
                       // graph should
-        int i, j, v = vertex, e = edge, neg = 0;
+        int i;
+        int j;
+        int v = vertex;
+        int e = edge;
+        int neg = 0;
         double[] dist = new double[v]; // Distance array for holding the finalized shortest path
                                        // distance between source
         // and all vertices
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java b/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
index dadab2e5063c..d2b76e8e06b1 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
@@ -22,7 +22,8 @@ class Node {
 
     class Edge {
 
-        Node startNode, endNode;
+        Node startNode;
+        Node endNode;
 
         Edge(Node startNode, Node endNode) {
             this.startNode = startNode;
@@ -46,7 +47,8 @@ class Edge {
      * @param endNode the ending Node from the edge
      */
     public void addEdge(E startNode, E endNode) {
-        Node start = null, end = null;
+        Node start = null;
+        Node end = null;
         for (Node node : nodeList) {
             if (startNode.compareTo(node.name) == 0) {
                 start = node;
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java b/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
index 06debf3dcb7f..b67c5512e622 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
@@ -5,7 +5,8 @@
 
 class Cycle {
 
-    private int nodes, edges;
+    private final int nodes;
+    private final int edges;
     private int[][] adjacencyMatrix;
     private boolean[] visited;
     ArrayList<ArrayList<Integer>> cycles = new ArrayList<ArrayList<Integer>>();
@@ -27,7 +28,8 @@ class Cycle {
         System.out.println("Enter the details of each edges <Start Node> <End Node>");
 
         for (int i = 0; i < edges; i++) {
-            int start, end;
+            int start;
+            int end;
             start = in.nextInt();
             end = in.nextInt();
             adjacencyMatrix[start][end] = 1;
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java b/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
index 3eff999bc921..865c276f0e20 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
@@ -9,7 +9,8 @@ class dijkstras {
     int k = 9;
 
     int minDist(int[] dist, Boolean[] Set) {
-        int min = Integer.MAX_VALUE, min_index = -1;
+        int min = Integer.MAX_VALUE;
+        int min_index = -1;
 
         for (int r = 0; r < k; r++) {
             if (!Set[r] && dist[r] <= min) {
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java b/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java
index 3a13f6a698bd..b0970f36ddc5 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java
@@ -75,7 +75,8 @@ public boolean removeEdge(E from, E to) {
      * already did
      */
     public boolean addEdge(E from, E to) {
-        Vertex fromV = null, toV = null;
+        Vertex fromV = null;
+        Vertex toV = null;
         for (Vertex v : vertices) {
             if (from.compareTo(v.data) == 0) { // see if from vertex already exists
                 fromV = v;
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java b/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
index 0016abef2419..d12f631db6f1 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
@@ -8,7 +8,8 @@
  */
 public class HamiltonianCycle {
 
-    private int V, pathCount;
+    private int V;
+    private int pathCount;
     private int[] cycle;
     private int[][] graph;
 
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java b/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
index 24fcbe7f90af..0d9eb87aedc0 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
@@ -14,7 +14,8 @@ class PrimMST {
     // value, from the set of vertices not yet included in MST
     int minKey(int[] key, Boolean[] mstSet) {
         // Initialize min value
-        int min = Integer.MAX_VALUE, min_index = -1;
+        int min = Integer.MAX_VALUE;
+        int min_index = -1;
 
         for (int v = 0; v < V; v++) {
             if (!mstSet[v] && key[v] < min) {
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
index 3fa6a812ec53..6f382766b3b1 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
@@ -66,8 +66,10 @@ public int hashFunction2(int key) {
      */
 
     public void insertKey2HashTable(int key) {
-        Integer wrappedInt = key, temp;
-        int hash, loopCounter = 0;
+        Integer wrappedInt = key;
+        Integer temp;
+        int hash;
+        int loopCounter = 0;
 
         if (isFull()) {
             System.out.println("Hash table is full, lengthening & rehashing table");
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
index b4f0afc63729..ec853af54b9a 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
@@ -7,7 +7,8 @@ private Main() {
     }
 
     public static void main(String[] args) {
-        int choice, key;
+        int choice;
+        int key;
 
         HashMap h = new HashMap(7);
         Scanner In = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
index 6681253d7844..01b6ebb8f90f 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
@@ -7,7 +7,8 @@ private MainCuckooHashing() {
     }
 
     public static void main(String[] args) {
-        int choice, key;
+        int choice;
+        int key;
 
         HashMapCuckooHashing h = new HashMapCuckooHashing(7);
         Scanner In = new Scanner(System.in);
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
index d21f8d6e71dc..a48d99f89864 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
@@ -13,9 +13,11 @@
  */
 
 public class LeftistHeap {
-    private final class Node {
-        private int element, npl;
-        private Node left, right;
+    private static final class Node {
+        private final int element;
+        private int npl;
+        private Node left;
+        private Node right;
 
         // Node constructor setting the data element and left/right pointers to null
         private Node(int element) {
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
index f379e9eccded..bca3c77f2724 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
@@ -82,13 +82,15 @@ public void swapNodes(int valueFirst, int valueSecond) {
         if (valueFirst == valueSecond) {
             return;
         }
-        Node previousA = null, currentA = head;
+        Node previousA = null;
+        Node currentA = head;
         while (currentA != null && currentA.value != valueFirst) {
             previousA = currentA;
             currentA = currentA.next;
         }
 
-        Node previousB = null, currentB = head;
+        Node previousB = null;
+        Node currentB = head;
         while (currentB != null && currentB.value != valueSecond) {
             previousB = currentB;
             currentB = currentB.next;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java b/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java
index b56a71421ed3..7b959b085353 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java
@@ -9,7 +9,9 @@ private class Node {
         private int key;
         private int balance;
         private int height;
-        private Node left, right, parent;
+        private Node left;
+        private Node right;
+        private Node parent;
 
         Node(int k, Node p) {
             key = k;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/LCA.java b/src/main/java/com/thealgorithms/datastructures/trees/LCA.java
index 701077b0a549..95a289493007 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/LCA.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/LCA.java
@@ -14,14 +14,16 @@ public static void main(String[] args) {
         ArrayList<ArrayList<Integer>> adj = new ArrayList<>();
 
         // v is the number of vertices and e is the number of edges
-        int v = SCANNER.nextInt(), e = v - 1;
+        int v = SCANNER.nextInt();
+        int e = v - 1;
 
         for (int i = 0; i < v; i++) {
             adj.add(new ArrayList<Integer>());
         }
 
         // Storing the given tree as an adjacency list
-        int to, from;
+        int to;
+        int from;
         for (int i = 0; i < e; i++) {
             to = SCANNER.nextInt();
             from = SCANNER.nextInt();
@@ -40,7 +42,8 @@ public static void main(String[] args) {
         dfs(adj, 0, -1, parent, depth);
 
         // Inputting the two vertices whose LCA is to be calculated
-        int v1 = SCANNER.nextInt(), v2 = SCANNER.nextInt();
+        int v1 = SCANNER.nextInt();
+        int v2 = SCANNER.nextInt();
 
         // Outputting the LCA
         System.out.println(getLCA(v1, v2, depth, parent));
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java b/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java
index 6eff3c38b94c..1d8febff4b5f 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java
@@ -10,10 +10,12 @@ public class LazySegmentTree {
      */
     static class Node {
 
-        private final int start, end; // start and end of the segment represented by this node
+        private final int start;
+        private final int end; // start and end of the segment represented by this node
         private int value; // value is the sum of all elements in the range [start, end)
         private int lazy; // lazied value that should be added to children nodes
-        Node left, right; // left and right children
+        Node left;
+        Node right; // left and right children
 
         Node(int start, int end, int value) {
             this.start = start;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java b/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
index 0fcf1324a4ce..88343db3d0e8 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
@@ -10,7 +10,8 @@ class TreeNode {
     // Members
 
     int key;
-    TreeNode left, right;
+    TreeNode left;
+    TreeNode right;
 
     // Constructor
     TreeNode(int key) {
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java b/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
index f2954f28495f..c7cb108d6b77 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
@@ -12,8 +12,11 @@ public class RedBlackBST {
 
     private class Node {
 
-        int key = -1, color = B;
-        Node left = nil, right = nil, p = nil;
+        int key = -1;
+        int color = B;
+        Node left = nil;
+        Node right = nil;
+        Node p = nil;
 
         Node(int key) {
             this.key = key;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java b/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java
index b1123a224223..cf56731fb079 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java
@@ -29,7 +29,8 @@ public class TreeRandomNode {
     private final class Node {
 
         int item;
-        Node left, right;
+        Node left;
+        Node right;
     }
 
     // Using an arraylist to store the inorder traversal of the given binary tree
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java
index 63a75f6a2c9b..c1d15390d4b9 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java
@@ -47,7 +47,8 @@ public static ArrayList<Integer> verticalTraversal(BinaryTree.Node root) {
 
         /* min and max stores leftmost and right most index to
                  later print the tree in vertical fashion.*/
-        int max = 0, min = 0;
+        int max = 0;
+        int min = 0;
         queue.offer(root);
         index.offer(0);
 
diff --git a/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java b/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java
index a70b16b0d069..7c28797c0791 100644
--- a/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java
+++ b/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java
@@ -28,7 +28,8 @@ public static long calculatePower(long x, long y) {
 
     // iterative function to calculate a to the power of b
     long power(long N, long M) {
-        long power = N, sum = 1;
+        long power = N;
+        long sum = 1;
         while (M > 0) {
             if ((M & 1) == 1) {
                 sum *= power;
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java b/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
index 7a7b0f006b57..6db30514db68 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
@@ -71,7 +71,8 @@ then take the minimum of the various operations(i.e insertion,removal,substituti
 
     public static void main(String[] args) {
         Scanner input = new Scanner(System.in);
-        String s1, s2;
+        String s1;
+        String s2;
         System.out.println("Enter the First String");
         s1 = input.nextLine();
         System.out.println("Enter the Second String");
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java b/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java
index c50522421d47..be52ab166f18 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java
@@ -10,7 +10,8 @@ private EggDropping() {
     // min trials with n eggs and m floors
     public static int minTrials(int n, int m) {
         int[][] eggFloor = new int[n + 1][m + 1];
-        int result, x;
+        int result;
+        int x;
 
         for (int i = 1; i <= n; i++) {
             eggFloor[i][0] = 0; // Zero trial for zero floor.
@@ -41,7 +42,8 @@ public static int minTrials(int n, int m) {
     }
 
     public static void main(String[] args) {
-        int n = 2, m = 4;
+        int n = 2;
+        int m = 4;
         // result outputs min no. of trials in worst case for n eggs and m floors
         int result = minTrials(n, m);
         System.out.println(result);
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
index 2d768df55a7a..5855030fc65c 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
@@ -86,7 +86,9 @@ public static int fibOptimized(int n) {
         if (n == 0) {
             return 0;
         }
-        int prev = 0, res = 1, next;
+        int prev = 0;
+        int res = 1;
+        int next;
         for (int i = 2; i <= n; i++) {
             next = prev + res;
             prev = res;
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java b/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
index b57dec97b88d..6168ec6ec09f 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
@@ -11,7 +11,8 @@ private FordFulkerson() {
     static final int INF = 987654321;
     // edges
     static int vertexCount;
-    static int[][] capacity, flow;
+    static int[][] capacity;
+    static int[][] flow;
 
     public static void main(String[] args) {
         System.out.println("Vertex Count : 6");
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
index 028c06d38dbd..573d1217e09e 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
@@ -11,7 +11,8 @@ private KadaneAlgorithm() {
     }
 
     public static boolean max_Sum(int[] a, int predicted_answer) {
-        int sum = a[0], running_sum = 0;
+        int sum = a[0];
+        int running_sum = 0;
         for (int k : a) {
             running_sum = running_sum + k;
             // running sum of all the indexs are stored
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java
index bf43aab489c9..2d1fa1d1153f 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java
@@ -41,7 +41,8 @@ public static String getLCS(String str1, String str2) {
 
     public static String lcsString(String str1, String str2, int[][] lcsMatrix) {
         StringBuilder lcs = new StringBuilder();
-        int i = str1.length(), j = str2.length();
+        int i = str1.length();
+        int j = str2.length();
         while (i > 0 && j > 0) {
             if (str1.charAt(i - 1) == str2.charAt(j - 1)) {
                 lcs.append(str1.charAt(i - 1));
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
index 489adcca66ed..2101ba702257 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
@@ -23,7 +23,8 @@ private static String LPS(String input) {
             return input;
         }
         boolean[][] arr = new boolean[input.length()][input.length()];
-        int start = 0, end = 0;
+        int start = 0;
+        int end = 0;
         for (int g = 0; g < input.length(); g++) {
             for (int i = 0, j = g; j < input.length(); i++, j++) {
                 if (g == 0) {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java b/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
index 2c6643e39c47..deb101c20073 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
@@ -31,7 +31,9 @@ public static int minimalpartitions(String word) {
         int[] minCuts = new int[len];
         boolean[][] isPalindrome = new boolean[len][len];
 
-        int i, j, L; // different looping variables
+        int i;
+        int j;
+        int L; // different looping variables
 
         // Every substring of length 1 is a palindrome
         for (i = 0; i < len; i++) {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java b/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
index 68387b7d2ed7..0ba25fa180f1 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
@@ -23,7 +23,8 @@ static int shortestSuperSequence(String X, String Y) {
     // for X[0..m - 1], Y[0..n - 1]
     static int lcs(String X, String Y, int m, int n) {
         int[][] L = new int[m + 1][n + 1];
-        int i, j;
+        int i;
+        int j;
 
         // Following steps build L[m + 1][n + 1]
         // in bottom up fashion. Note that
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java b/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
index 6abd6b234195..407566f481a0 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
@@ -18,7 +18,9 @@ public static int compute(int n) {
         if (n == 0) return 0;
         if (n == 1 || n == 2) return 1;
 
-        int first = 0, second = 1, third = 1;
+        int first = 0;
+        int second = 1;
+        int third = 1;
 
         for (int i = 3; i <= n; i++) {
             int next = first + second + third;
diff --git a/src/main/java/com/thealgorithms/io/BufferedReader.java b/src/main/java/com/thealgorithms/io/BufferedReader.java
index 477a52bb5c30..fa0237a48049 100644
--- a/src/main/java/com/thealgorithms/io/BufferedReader.java
+++ b/src/main/java/com/thealgorithms/io/BufferedReader.java
@@ -27,7 +27,8 @@ public class BufferedReader {
     /**
      * posRead -> indicates the next byte to read
      */
-    private int posRead = 0, bufferPos = 0;
+    private int posRead = 0;
+    private int bufferPos = 0;
 
     private boolean foundEof = false;
 
diff --git a/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java b/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
index d9dd82c7bbe2..560ce3aabd1a 100644
--- a/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
+++ b/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
@@ -24,7 +24,8 @@ private AutomorphicNumber() {
     public static boolean isAutomorphic(long n) {
         if (n < 0) return false;
         long square = n * n; // Calculating square of the number
-        long t = n, numberOfdigits = 0;
+        long t = n;
+        long numberOfdigits = 0;
         while (t > 0) {
             numberOfdigits++; // Calculating number of digits in n
             t /= 10;
diff --git a/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java b/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
index 7f96af388611..a2a327117700 100644
--- a/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
+++ b/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
@@ -13,7 +13,10 @@ private DeterminantOfMatrix() {
     // Determinant calculator
     //@return determinant of the input matrix
     static int determinant(int[][] a, int n) {
-        int det = 0, sign = 1, p = 0, q = 0;
+        int det = 0;
+        int sign = 1;
+        int p = 0;
+        int q = 0;
         if (n == 1) {
             det = a[0][0];
         } else {
diff --git a/src/main/java/com/thealgorithms/maths/FFT.java b/src/main/java/com/thealgorithms/maths/FFT.java
index 8f21254794c0..573275544439 100644
--- a/src/main/java/com/thealgorithms/maths/FFT.java
+++ b/src/main/java/com/thealgorithms/maths/FFT.java
@@ -24,7 +24,8 @@ private FFT() {
      */
     static class Complex {
 
-        private double real, img;
+        private double real;
+        private double img;
 
         /**
          * Default Constructor. Creates the complex number 0.
diff --git a/src/main/java/com/thealgorithms/maths/FindKthNumber.java b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
index bf7a4985f7f6..daea3f96332b 100644
--- a/src/main/java/com/thealgorithms/maths/FindKthNumber.java
+++ b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
@@ -41,7 +41,8 @@ private static int[] generateArray(int capacity) {
     }
 
     private static int findKthMax(int[] nums, int k) {
-        int start = 0, end = nums.length;
+        int start = 0;
+        int end = nums.length;
         while (start < end) {
             int pivot = partition(nums, start, end);
             if (k == pivot) {
diff --git a/src/main/java/com/thealgorithms/maths/Gaussian.java b/src/main/java/com/thealgorithms/maths/Gaussian.java
index 5591bfd1068c..07c0f67f06e2 100644
--- a/src/main/java/com/thealgorithms/maths/Gaussian.java
+++ b/src/main/java/com/thealgorithms/maths/Gaussian.java
@@ -8,7 +8,8 @@ private Gaussian() {
 
     public static ArrayList<Double> gaussian(int mat_size, ArrayList<Double> matrix) {
         ArrayList<Double> answerArray = new ArrayList<Double>();
-        int i, j = 0;
+        int i;
+        int j = 0;
 
         double[][] mat = new double[mat_size + 1][mat_size + 1];
         double[][] x = new double[mat_size][mat_size + 1];
@@ -43,7 +44,8 @@ public static double[][] gaussianElimination(int mat_size, int i, double[][] mat
     // calculate the x_1, x_2, ... values of the gaussian and save it in an arraylist.
     public static ArrayList<Double> valueOfGaussian(int mat_size, double[][] x, double[][] mat) {
         ArrayList<Double> answerArray = new ArrayList<Double>();
-        int i, j;
+        int i;
+        int j;
 
         for (i = 0; i < mat_size; i++) {
             for (j = 0; j <= mat_size; j++) {
diff --git a/src/main/java/com/thealgorithms/maths/KeithNumber.java b/src/main/java/com/thealgorithms/maths/KeithNumber.java
index 194c4ba3c5bd..c2d64dcad493 100644
--- a/src/main/java/com/thealgorithms/maths/KeithNumber.java
+++ b/src/main/java/com/thealgorithms/maths/KeithNumber.java
@@ -11,9 +11,10 @@ private KeithNumber() {
     // user-defined function that checks if the given number is Keith or not
     static boolean isKeith(int x) {
         // List stores all the digits of the X
-        ArrayList<Integer> terms = new ArrayList<Integer>();
+        ArrayList<Integer> terms = new ArrayList<>();
         // n denotes the number of digits
-        int temp = x, n = 0;
+        int temp = x;
+        int n = 0;
         // executes until the condition becomes false
         while (temp > 0) {
             // determines the last digit of the number and add it to the List
@@ -25,7 +26,8 @@ static boolean isKeith(int x) {
         }
         // reverse the List
         Collections.reverse(terms);
-        int next_term = 0, i = n;
+        int next_term = 0;
+        int i = n;
         // finds next term for the series
         // loop executes until the condition returns true
         while (next_term < x) {
diff --git a/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java b/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
index 228ff0b50b2b..db79340f0a99 100644
--- a/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
+++ b/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
@@ -30,7 +30,8 @@ public static void main(String[] args) {
      * get least common multiple from two number
      */
     public static int lcm(int num1, int num2) {
-        int high, num3;
+        int high;
+        int num3;
         int cmv = 0;
         /*
          * value selection for the numerator
diff --git a/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java b/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
index ee92470ca35f..f58a56aa00c2 100644
--- a/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
+++ b/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
@@ -13,7 +13,8 @@ private NonRepeatingElement() {
 
     public static void main(String[] args) {
         try (Scanner sc = new Scanner(System.in)) {
-            int i, res = 0;
+            int i;
+            int res = 0;
             System.out.println("Enter the number of elements in the array");
             int n = sc.nextInt();
             if ((n & 1) == 1) {
@@ -42,7 +43,8 @@ public static void main(String[] args) {
 
             // Finding the rightmost set bit
             res = res & (-res);
-            int num1 = 0, num2 = 0;
+            int num1 = 0;
+            int num2 = 0;
 
             for (i = 0; i < n; i++) {
                 if ((res & arr[i]) > 0) { // Case 1 explained below
diff --git a/src/main/java/com/thealgorithms/maths/PollardRho.java b/src/main/java/com/thealgorithms/maths/PollardRho.java
index 8855a463e81c..7fa913b21b7e 100644
--- a/src/main/java/com/thealgorithms/maths/PollardRho.java
+++ b/src/main/java/com/thealgorithms/maths/PollardRho.java
@@ -59,7 +59,9 @@ static int g(int base, int modulus) {
      * @throws RuntimeException object if GCD of given number cannot be found
      */
     static int pollardRho(int number) {
-        int x = 2, y = 2, d = 1;
+        int x = 2;
+        int y = 2;
+        int d = 1;
         while (d == 1) {
             // tortoise move
             x = g(x, number);
diff --git a/src/main/java/com/thealgorithms/maths/PrimeCheck.java b/src/main/java/com/thealgorithms/maths/PrimeCheck.java
index 4f928bfe451e..628a819aeba4 100644
--- a/src/main/java/com/thealgorithms/maths/PrimeCheck.java
+++ b/src/main/java/com/thealgorithms/maths/PrimeCheck.java
@@ -56,7 +56,8 @@ public static boolean isPrime(int n) {
      */
     public static boolean fermatPrimeChecking(int n, int iteration) {
         long a;
-        int up = n - 2, down = 2;
+        int up = n - 2;
+        int down = 2;
         for (int i = 0; i < iteration; i++) {
             a = (long) Math.floor(Math.random() * (up - down + 1) + down);
             if (modPow(a, n - 1, n) != 1) {
diff --git a/src/main/java/com/thealgorithms/misc/matrixTranspose.java b/src/main/java/com/thealgorithms/misc/matrixTranspose.java
index bf81675af641..40634f18b5f6 100644
--- a/src/main/java/com/thealgorithms/misc/matrixTranspose.java
+++ b/src/main/java/com/thealgorithms/misc/matrixTranspose.java
@@ -31,7 +31,10 @@ public static void main(String[] args) {
          * @return Nothing.
          */
         Scanner sc = new Scanner(System.in);
-        int i, j, row, column;
+        int i;
+        int j;
+        int row;
+        int column;
         System.out.println("Enter the number of rows in the 2D matrix:");
 
         /*
diff --git a/src/main/java/com/thealgorithms/others/BankersAlgorithm.java b/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
index fb699d89c379..baa180431ce4 100644
--- a/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
@@ -113,7 +113,8 @@ static boolean checkSafeSystem(int[] processes, int[] availableArray, int[][] ma
      * This is main method of Banker's Algorithm
      */
     public static void main(String[] args) {
-        int numberOfProcesses, numberOfResources;
+        int numberOfProcesses;
+        int numberOfResources;
 
         Scanner sc = new Scanner(System.in);
 
diff --git a/src/main/java/com/thealgorithms/others/Dijkstra.java b/src/main/java/com/thealgorithms/others/Dijkstra.java
index 56fc32a96259..e2a778f8d6c3 100644
--- a/src/main/java/com/thealgorithms/others/Dijkstra.java
+++ b/src/main/java/com/thealgorithms/others/Dijkstra.java
@@ -63,7 +63,8 @@ class Graph {
      */
     public static class Edge {
 
-        public final String v1, v2;
+        public final String v1;
+        public final String v2;
         public final int dist;
 
         Edge(String v1, String v2, int dist) {
@@ -198,7 +199,8 @@ public void dijkstra(String startName) {
      * Implementation of dijkstra's algorithm using a binary heap.
      */
     private void dijkstra(final NavigableSet<Vertex> q) {
-        Vertex u, v;
+        Vertex u;
+        Vertex v;
         while (!q.isEmpty()) {
             // vertex with shortest distance (first iteration will return source)
             u = q.pollFirst();
diff --git a/src/main/java/com/thealgorithms/others/FibbonaciSeries.java b/src/main/java/com/thealgorithms/others/FibbonaciSeries.java
index bb1500e5cdc1..a4815296e547 100644
--- a/src/main/java/com/thealgorithms/others/FibbonaciSeries.java
+++ b/src/main/java/com/thealgorithms/others/FibbonaciSeries.java
@@ -23,7 +23,8 @@ public static void main(String[] args) {
         // Get input from the user
         Scanner scan = new Scanner(System.in);
         int n = scan.nextInt();
-        int first = 0, second = 1;
+        int first = 0;
+        int second = 1;
         scan.close();
         while (first <= n) {
             // print first fibo 0 then add second fibo into it while updating second as well
diff --git a/src/main/java/com/thealgorithms/others/FloydTriangle.java b/src/main/java/com/thealgorithms/others/FloydTriangle.java
index 9e8879838e38..fbeaec339248 100644
--- a/src/main/java/com/thealgorithms/others/FloydTriangle.java
+++ b/src/main/java/com/thealgorithms/others/FloydTriangle.java
@@ -9,7 +9,8 @@ private FloydTriangle() {
     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
         System.out.println("Enter the number of rows which you want in your Floyd Triangle: ");
-        int r = sc.nextInt(), n = 0;
+        int r = sc.nextInt();
+        int n = 0;
         sc.close();
         for (int i = 0; i < r; i++) {
             for (int j = 0; j <= i; j++) {
diff --git a/src/main/java/com/thealgorithms/others/GuassLegendre.java b/src/main/java/com/thealgorithms/others/GuassLegendre.java
index 5d2d585d19f5..5ecfdf2b84cc 100644
--- a/src/main/java/com/thealgorithms/others/GuassLegendre.java
+++ b/src/main/java/com/thealgorithms/others/GuassLegendre.java
@@ -21,7 +21,10 @@ static double pi(int l) {
          * l: No of loops to run
          */
 
-        double a = 1, b = Math.pow(2, -0.5), t = 0.25, p = 1;
+        double a = 1;
+        double b = Math.pow(2, -0.5);
+        double t = 0.25;
+        double p = 1;
         for (int i = 0; i < l; ++i) {
             double[] temp = update(a, b, t, p);
             a = temp[0];
diff --git a/src/main/java/com/thealgorithms/others/KochSnowflake.java b/src/main/java/com/thealgorithms/others/KochSnowflake.java
index 1762d6cfac0f..ab426bb0ca9d 100644
--- a/src/main/java/com/thealgorithms/others/KochSnowflake.java
+++ b/src/main/java/com/thealgorithms/others/KochSnowflake.java
@@ -178,7 +178,8 @@ private static BufferedImage GetImage(ArrayList<Vector2> vectors, int imageWidth
      */
     private static class Vector2 {
 
-        double x, y;
+        double x;
+        double y;
 
         Vector2(double x, double y) {
             this.x = x;
diff --git a/src/main/java/com/thealgorithms/others/Krishnamurthy.java b/src/main/java/com/thealgorithms/others/Krishnamurthy.java
index 465d7e9c4265..8e5ba7c6f1c7 100644
--- a/src/main/java/com/thealgorithms/others/Krishnamurthy.java
+++ b/src/main/java/com/thealgorithms/others/Krishnamurthy.java
@@ -7,7 +7,8 @@ private Krishnamurthy() {
     }
 
     static int fact(int n) {
-        int i, p = 1;
+        int i;
+        int p = 1;
         for (i = n; i >= 1; i--) {
             p = p * i;
         }
@@ -16,7 +17,9 @@ static int fact(int n) {
 
     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
-        int a, b, s = 0;
+        int a;
+        int b;
+        int s = 0;
         System.out.print("Enter the number : ");
         a = sc.nextInt();
         int n = a;
diff --git a/src/main/java/com/thealgorithms/others/LinearCongruentialGenerator.java b/src/main/java/com/thealgorithms/others/LinearCongruentialGenerator.java
index 346ae9f82186..36bcca3edc00 100644
--- a/src/main/java/com/thealgorithms/others/LinearCongruentialGenerator.java
+++ b/src/main/java/com/thealgorithms/others/LinearCongruentialGenerator.java
@@ -9,7 +9,10 @@
  */
 public class LinearCongruentialGenerator {
 
-    private double a, c, m, previousValue;
+    private final double a;
+    private final double c;
+    private final double m;
+    private double previousValue;
 
     /**
      * *
diff --git a/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java b/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java
index 2672dc6f2892..cd2cd02ab908 100644
--- a/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java
@@ -55,7 +55,9 @@ public static void main(String[] args) {
      * @return The optimal score for the player that made the first move.
      */
     public int miniMax(int depth, boolean isMaximizer, int index, boolean verbose) {
-        int bestScore, score1, score2;
+        int bestScore;
+        int score1;
+        int score2;
 
         if (depth == height) { // Leaf node reached.
             return scores[index];
diff --git a/src/main/java/com/thealgorithms/others/PageRank.java b/src/main/java/com/thealgorithms/others/PageRank.java
index faade993cccc..960034fdb701 100644
--- a/src/main/java/com/thealgorithms/others/PageRank.java
+++ b/src/main/java/com/thealgorithms/others/PageRank.java
@@ -5,7 +5,9 @@
 class PageRank {
 
     public static void main(String[] args) {
-        int nodes, i, j;
+        int nodes;
+        int i;
+        int j;
         Scanner in = new Scanner(System.in);
         System.out.print("Enter the Number of WebPages: ");
         nodes = in.nextInt();
diff --git a/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java b/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
index 985b8b2631a9..2ea3de814d0d 100644
--- a/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
+++ b/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
@@ -58,7 +58,8 @@ static void rotate(int[][] a) {
                 }
             }
         }
-        int i = 0, k = n - 1;
+        int i = 0;
+        int k = n - 1;
         while (i < k) {
             for (int j = 0; j < n; j++) {
                 int temp = a[i][j];
diff --git a/src/main/java/com/thealgorithms/others/SkylineProblem.java b/src/main/java/com/thealgorithms/others/SkylineProblem.java
index 149adf4349cf..ece398e70405 100644
--- a/src/main/java/com/thealgorithms/others/SkylineProblem.java
+++ b/src/main/java/com/thealgorithms/others/SkylineProblem.java
@@ -59,7 +59,8 @@ public ArrayList<Skyline> findSkyline(int start, int end) {
     }
 
     public ArrayList<Skyline> mergeSkyline(ArrayList<Skyline> sky1, ArrayList<Skyline> sky2) {
-        int currentH1 = 0, currentH2 = 0;
+        int currentH1 = 0;
+        int currentH2 = 0;
         ArrayList<Skyline> skyline = new ArrayList<>();
         int maxH = 0;
 
diff --git a/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java b/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
index 2bc5f54ce0dd..c14c91ba6c37 100644
--- a/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
@@ -24,7 +24,9 @@ public class SJFScheduling {
         sortByArrivalTime();
     }
     protected void sortByArrivalTime() {
-        int size = processes.size(), i, j;
+        int size = processes.size();
+        int i;
+        int j;
         ProcessDetails temp;
         for (i = 0; i < size; i++) {
             for (j = i + 1; j < size - 1; j++) {
@@ -44,8 +46,12 @@ protected void sortByArrivalTime() {
     public void scheduleProcesses() {
         ArrayList<ProcessDetails> ready = new ArrayList<>();
 
-        int size = processes.size(), runtime, time = 0;
-        int executed = 0, j, k = 0;
+        int size = processes.size();
+        int runtime;
+        int time = 0;
+        int executed = 0;
+        int j;
+        int k = 0;
         ProcessDetails running;
 
         if (size == 0) {
@@ -85,8 +91,11 @@ private ProcessDetails findShortestJob(ArrayList<ProcessDetails> ReadyProcesses)
         if (ReadyProcesses.isEmpty()) {
             return null;
         }
-        int i, size = ReadyProcesses.size();
-        int minBurstTime = ReadyProcesses.get(0).getBurstTime(), temp, positionOfShortestJob = 0;
+        int i;
+        int size = ReadyProcesses.size();
+        int minBurstTime = ReadyProcesses.get(0).getBurstTime();
+        int temp;
+        int positionOfShortestJob = 0;
 
         for (i = 1; i < size; i++) {
             temp = ReadyProcesses.get(i).getBurstTime();
diff --git a/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java b/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java
index ad8aeabacad8..99214fff20c4 100644
--- a/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java
@@ -31,7 +31,8 @@ public SRTFScheduling(ArrayList<ProcessDetails> processes) {
     }
 
     public void evaluateScheduling() {
-        int time = 0, cr = 0; // cr=current running process, time= units of time
+        int time = 0;
+        int cr = 0; // cr=current running process, time= units of time
         int n = processes.size();
         int[] remainingTime = new int[n];
 
diff --git a/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java b/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
index 164f906a38b8..2794c4bde1d7 100644
--- a/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
+++ b/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
@@ -13,13 +13,16 @@ private BinarySearch2dArray() {
     }
 
     static int[] BinarySearch(int[][] arr, int target) {
-        int rowCount = arr.length, colCount = arr[0].length;
+        int rowCount = arr.length;
+        int colCount = arr[0].length;
 
         if (rowCount == 1) {
             return binarySearch(arr, target, 0, 0, colCount);
         }
 
-        int startRow = 0, endRow = rowCount - 1, midCol = colCount / 2;
+        int startRow = 0;
+        int endRow = rowCount - 1;
+        int midCol = colCount / 2;
 
         while (startRow < endRow - 1) {
             int midRow = startRow + (endRow - startRow) / 2; // getting the index of middle row
diff --git a/src/main/java/com/thealgorithms/searches/InterpolationSearch.java b/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
index 215ecdef7987..aa1ff412b6a7 100644
--- a/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
+++ b/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
@@ -23,7 +23,8 @@ class InterpolationSearch {
      */
     public int find(int[] array, int key) {
         // Find indexes of two corners
-        int start = 0, end = (array.length - 1);
+        int start = 0;
+        int end = (array.length - 1);
 
         // Since array is sorted, an element present
         // in array must be in range defined by corner
diff --git a/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java b/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
index 324b8f582937..49a86e4e53a8 100644
--- a/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
@@ -32,7 +32,10 @@ public final class IterativeBinarySearch implements SearchAlgorithm {
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
-        int l, r, k, cmp;
+        int l;
+        int r;
+        int k;
+        int cmp;
 
         l = 0;
         r = array.length - 1;
diff --git a/src/main/java/com/thealgorithms/searches/LinearSearchThread.java b/src/main/java/com/thealgorithms/searches/LinearSearchThread.java
index d3d04e4f79cc..b354d312d1b3 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearchThread.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearchThread.java
@@ -42,7 +42,8 @@ public static void main(String[] args) {
 class Searcher extends Thread {
 
     private final int[] arr;
-    private final int left, right;
+    private final int left;
+    private final int right;
     private final int x;
     private boolean found;
 
diff --git a/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java b/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java
index 6ec1aa5ceb5e..5c7a914e3bf2 100644
--- a/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java
+++ b/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java
@@ -57,7 +57,10 @@ public static void main(String[] args) {
         // TODO Auto-generated method stub
         Scanner sc = new Scanner(System.in);
         int[][] arr;
-        int i, j, rows = sc.nextInt(), col = sc.nextInt();
+        int i;
+        int j;
+        int rows = sc.nextInt();
+        int col = sc.nextInt();
         arr = new int[rows][col];
         for (i = 0; i < rows; i++) {
             for (j = 0; j < col; j++) {
diff --git a/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java b/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java
index dc3a9a100fa0..c88c7bd099f6 100644
--- a/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java
@@ -16,7 +16,8 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         int length = array.length;
         int left = 0;
         int right = length - 1;
-        int swappedLeft, swappedRight;
+        int swappedLeft;
+        int swappedRight;
         while (left < right) {
             // front
             swappedRight = 0;
diff --git a/src/main/java/com/thealgorithms/sorts/DNFSort.java b/src/main/java/com/thealgorithms/sorts/DNFSort.java
index 7074e2cbe63a..139f3690c70f 100644
--- a/src/main/java/com/thealgorithms/sorts/DNFSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DNFSort.java
@@ -9,7 +9,8 @@ private DNFSort() {
     static void sort012(int[] a, int arr_size) {
         int low = 0;
         int high = arr_size - 1;
-        int mid = 0, temp;
+        int mid = 0;
+        int temp;
         while (mid <= high) {
             switch (a[mid]) {
             case 0: {
diff --git a/src/main/java/com/thealgorithms/sorts/LinkListSort.java b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
index 14f8394bac5b..daddae486621 100644
--- a/src/main/java/com/thealgorithms/sorts/LinkListSort.java
+++ b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
@@ -25,7 +25,10 @@ public static boolean isSorted(int[] p, int option) {
         switch (ch) {
         case 1:
             Task nm = new Task();
-            Node start = null, prev = null, fresh, ptr;
+            Node start = null;
+            Node prev = null;
+            Node fresh;
+            Node ptr;
             for (int i = 0; i < a.length; i++) {
                 // New nodes are created and values are added
                 fresh = new Node(); // Node class is called
@@ -50,7 +53,10 @@ public static boolean isSorted(int[] p, int option) {
             // The given array and the expected array is checked if both are same then true
             // is displayed else false is displayed
         case 2:
-            Node start1 = null, prev1 = null, fresh1, ptr1;
+            Node start1 = null;
+            Node prev1 = null;
+            Node fresh1;
+            Node ptr1;
             for (int i1 = 0; i1 < a.length; i1++) {
                 // New nodes are created and values are added
                 fresh1 = new Node(); // New node is created
@@ -76,7 +82,10 @@ public static boolean isSorted(int[] p, int option) {
             // is displayed else false is displayed
         case 3:
             Task2 mm = new Task2();
-            Node start2 = null, prev2 = null, fresh2, ptr2;
+            Node start2 = null;
+            Node prev2 = null;
+            Node fresh2;
+            Node ptr2;
             for (int i2 = 0; i2 < a.length; i2++) {
                 // New nodes are created and values are added
                 fresh2 = new Node(); // Node class is created
@@ -182,7 +191,9 @@ void task(int[] n, int i, int j) {
     }
 
     void task1(int[] n, int s, int m, int e) {
-        int i = s, k = 0, j = m + 1;
+        int i = s;
+        int k = 0;
+        int j = m + 1;
         int[] b = new int[e - s + 1];
         while (i <= m && j <= e) {
             if (n[j] >= n[i])
diff --git a/src/main/java/com/thealgorithms/sorts/MergeSort.java b/src/main/java/com/thealgorithms/sorts/MergeSort.java
index f4953e71d009..9949783ca21b 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSort.java
@@ -50,7 +50,8 @@ private <T extends Comparable<T>> void doSort(T[] arr, int left, int right) {
      */
     @SuppressWarnings("unchecked")
     private <T extends Comparable<T>> void merge(T[] arr, int left, int mid, int right) {
-        int i = left, j = mid + 1;
+        int i = left;
+        int j = mid + 1;
         System.arraycopy(arr, left, aux, left, right + 1 - left);
 
         for (int k = left; k <= right; k++) {
diff --git a/src/main/java/com/thealgorithms/sorts/TimSort.java b/src/main/java/com/thealgorithms/sorts/TimSort.java
index bb7ed8d549f4..85e16636c6ae 100644
--- a/src/main/java/com/thealgorithms/sorts/TimSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TimSort.java
@@ -31,7 +31,8 @@ public <T extends Comparable<T>> T[] sort(T[] a) {
     }
 
     private <T extends Comparable<T>> void merge(T[] a, int lo, int mid, int hi) {
-        int i = lo, j = mid + 1;
+        int i = lo;
+        int j = mid + 1;
         System.arraycopy(a, lo, aux, lo, hi + 1 - lo);
 
         for (int k = lo; k <= hi; k++) {
diff --git a/src/main/java/com/thealgorithms/stacks/LargestRectangle.java b/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
index b3004a284a15..0404d9c99508 100644
--- a/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
+++ b/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
@@ -12,7 +12,8 @@ private LargestRectangle() {
     }
 
     public static String largestRectanglehistogram(int[] heights) {
-        int n = heights.length, maxArea = 0;
+        int n = heights.length;
+        int maxArea = 0;
         Stack<int[]> st = new Stack<>();
         for (int i = 0; i < n; i++) {
             int start = i;
diff --git a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
index 6a0453d887c2..114b2dc37269 100644
--- a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
+++ b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
@@ -90,7 +90,8 @@ public static String getPostfixToInfix(String postfix) {
         Stack<String> stack = new Stack<>();
         StringBuilder valueString = new StringBuilder();
 
-        String operandA, operandB;
+        String operandA;
+        String operandB;
         char operator;
 
         for (int index = 0; index < postfix.length(); index++) {
diff --git a/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java b/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java
index 3619124745b4..99154542955f 100644
--- a/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java
+++ b/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java
@@ -7,7 +7,9 @@ private longestNonRepeativeSubstring() {
     }
 
     public static int lengthOfLongestSubstring(String s) {
-        int max = 0, start = 0, i = 0;
+        int max = 0;
+        int start = 0;
+        int i = 0;
         HashMap<Character, Integer> map = new HashMap<>();
 
         while (i < s.length()) {
diff --git a/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java b/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
index ea366ad83b3d..1af529f89459 100644
--- a/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
+++ b/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
@@ -6,10 +6,15 @@ private zigZagPattern() {
 
     public static String encode(String s, int numRows) {
         if (numRows < 2 || s.length() < numRows) return s;
-        int start = 0, index = 0, height = 1, depth = numRows;
+        int start = 0;
+        int index = 0;
+        int height = 1;
+        int depth = numRows;
         char[] zigZagedArray = new char[s.length()];
         while (depth != 0) {
-            int pointer = start, height_space = 2 + ((height - 2) * 2), depth_space = 2 + ((depth - 2) * 2);
+            int pointer = start;
+            int height_space = 2 + ((height - 2) * 2);
+            int depth_space = 2 + ((depth - 2) * 2);
             boolean bool = true;
             while (pointer < s.length()) {
                 zigZagedArray[index++] = s.charAt(pointer);

From 37c2a96fe2248ac554c2e474e71a6fbf78d2369a Mon Sep 17 00:00:00 2001
From: Bama Charan Chhandogi <b.c.chhandogi@gmail.com>
Date: Sun, 26 May 2024 17:28:00 +0530
Subject: [PATCH 0170/1338] style: enable `MissingSwitchDefault`  in checkstyle
 (#5179)

* Update directory

* Update directory

* Update directory

* Update directory

* add switch default

---------

Co-authored-by: BamaCharanChhandogi <BamaCharanChhandogi@users.noreply.github.com>
---
 DIRECTORY.md                                           | 10 +++++++---
 .../datastructures/hashmap/hashing/Main.java           |  3 +++
 .../hashmap/hashing/MainCuckooHashing.java             |  3 +++
 src/main/java/com/thealgorithms/misc/Sort012D.java     |  3 +++
 src/main/java/com/thealgorithms/sorts/DNFSort.java     |  2 ++
 .../java/com/thealgorithms/stacks/PostfixToInfix.java  |  4 ++--
 .../com/thealgorithms/strings/ValidParentheses.java    |  2 ++
 7 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a48e01f4ac04..c8b38bb20343 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -389,7 +389,7 @@
             * [PalindromeSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java)
             * [RangeInSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java)
             * [Sort012D](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sort012D.java)
-            * [Sparcity](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sparcity.java)
+            * [Sparsity](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sparsity.java)
             * [ThreeSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java)
             * [TwoSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/TwoSumProblem.java)
             * [WordBoggle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/WordBoggle.java)
@@ -439,12 +439,11 @@
             * [ReturnSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReturnSubsequence.java)
             * [ReverseStackUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
             * [RootPrecision](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RootPrecision.java)
-            * [RotateMatriceBy90Degree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RotateMatriceBy90Degree.java)
+            * [RotateMatrixBy90Degrees](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java)
             * [SieveOfEratosthenes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java)
             * [SkylineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SkylineProblem.java)
             * [StringMatchFiniteAutomata](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java)
             * [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Sudoku.java)
-            * [TopKWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TopKWords.java)
             * [TowerOfHanoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TowerOfHanoi.java)
             * [TwoPointers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TwoPointers.java)
             * [Verhoeff](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Verhoeff.java)
@@ -690,6 +689,7 @@
             * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
             * [KnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
             * [LevenshteinDistanceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
+            * [LongestIncreasingSubsequenceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java)
             * [MinimumPathSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java)
             * [MinimumSumPartitionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java)
             * [OptimalJobSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
@@ -730,6 +730,7 @@
             * [DigitalRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DigitalRootTest.java)
             * [DistanceFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java)
             * [DudeneyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java)
+            * [FactorialRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java)
             * [FactorialTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialTest.java)
             * [FastInverseSqrtTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java)
             * [FFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FFTTest.java)
@@ -762,7 +763,9 @@
             * [MillerRabinPrimalityCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java)
             * [MinValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MinValueTest.java)
             * [MobiusFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java)
+            * [ModeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ModeTest.java)
             * [NthUglyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java)
+            * [NumberOfDigitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java)
             * [PalindromeNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java)
             * [ParseIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ParseIntegerTest.java)
             * [PascalTriangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PascalTriangleTest.java)
@@ -853,6 +856,7 @@
             * [BogoSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BogoSortTest.java)
             * [BubbleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BubbleSortTest.java)
             * [BucketSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BucketSortTest.java)
+            * [CircleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CircleSortTest.java)
             * [CocktailShakerSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java)
             * [CombSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CombSortTest.java)
             * [DualPivotQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
index ec853af54b9a..f1dbb332057b 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
@@ -44,6 +44,9 @@ public static void main(String[] args) {
                 In.close();
                 return;
             }
+            default: {
+                throw new IllegalArgumentException("Unexpected value: " + choice);
+            }
             }
         }
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
index 01b6ebb8f90f..772e164239e0 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
@@ -62,6 +62,9 @@ public static void main(String[] args) {
                 h.reHashTableIncreasesTableSize();
                 break;
             }
+            default: {
+                throw new IllegalArgumentException("Unexpected value: " + choice);
+            }
             }
         }
     }
diff --git a/src/main/java/com/thealgorithms/misc/Sort012D.java b/src/main/java/com/thealgorithms/misc/Sort012D.java
index b51664ce7a5a..febe13f4fec3 100644
--- a/src/main/java/com/thealgorithms/misc/Sort012D.java
+++ b/src/main/java/com/thealgorithms/misc/Sort012D.java
@@ -51,6 +51,9 @@ public static void sort012(int[] a) {
                 h--;
                 break;
             }
+            default: {
+                throw new IllegalArgumentException("Unexpected value: " + a[mid]);
+            }
             }
         }
         System.out.println("the Sorted array is ");
diff --git a/src/main/java/com/thealgorithms/sorts/DNFSort.java b/src/main/java/com/thealgorithms/sorts/DNFSort.java
index 139f3690c70f..6e89bb65ad32 100644
--- a/src/main/java/com/thealgorithms/sorts/DNFSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DNFSort.java
@@ -31,6 +31,8 @@ static void sort012(int[] a, int arr_size) {
                 high--;
                 break;
             }
+            default:
+                throw new IllegalArgumentException("Unexpected value: " + a[mid]);
             }
         }
     }
diff --git a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
index 114b2dc37269..c69a511c2c17 100644
--- a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
+++ b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
@@ -28,9 +28,9 @@ public static boolean isOperator(char token) {
         case '*':
         case '^':
             return true;
+        default:
+            return false;
         }
-
-        return false;
     }
 
     public static boolean isValidPostfixExpression(String postfix) {
diff --git a/src/main/java/com/thealgorithms/strings/ValidParentheses.java b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
index b2759e5bcec9..947a39da4bde 100644
--- a/src/main/java/com/thealgorithms/strings/ValidParentheses.java
+++ b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
@@ -26,6 +26,8 @@ public static boolean isValid(String s) {
             case ']':
                 if (head == 0 || stack[--head] != '[') return false;
                 break;
+            default:
+                throw new IllegalArgumentException("Unexpected character: " + c);
             }
         }
         return head == 0;

From ea4dc15a249e47a772b60a0f22f0d0b836b5f423 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 26 May 2024 23:32:36 +0200
Subject: [PATCH 0171/1338] style: do not suppress `try` (#5167)

---
 pom.xml                                                    | 1 -
 src/main/java/com/thealgorithms/ciphers/ProductCipher.java | 1 -
 .../thealgorithms/datastructures/graphs/BellmanFord.java   | 1 -
 .../thealgorithms/datastructures/stacks/ReverseStack.java  | 1 -
 .../java/com/thealgorithms/maths/NonRepeatingElement.java  | 7 -------
 .../java/com/thealgorithms/others/InsertDeleteInArray.java | 1 -
 src/main/java/com/thealgorithms/sorts/LinkListSort.java    | 3 ---
 7 files changed, 15 deletions(-)

diff --git a/pom.xml b/pom.xml
index 21b5ec350917..134732953c03 100644
--- a/pom.xml
+++ b/pom.xml
@@ -79,7 +79,6 @@
                         <arg>-Xlint:all</arg>
                         <arg>-Xlint:-auxiliaryclass</arg>
                         <arg>-Xlint:-rawtypes</arg>
-                        <arg>-Xlint:-try</arg>
                         <arg>-Xlint:-unchecked</arg>
                         <arg>-Xlint:-lossy-conversions</arg>
                         <arg>-Werror</arg>
diff --git a/src/main/java/com/thealgorithms/ciphers/ProductCipher.java b/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
index fb63ed9b6ef9..d7eaea757001 100644
--- a/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/ProductCipher.java
@@ -68,7 +68,6 @@ public static void main(String[] args) {
 
             System.out.println("Plaintext: ");
             System.out.println(plaintext);
-            sc.close();
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
index a84a3ceff6b6..522e19787e8c 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
@@ -116,7 +116,6 @@ public void go() { // shows distance to all vertices // Interactive run for unde
                     System.out.println();
                 }
             }
-            sc.close();
         }
     }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java b/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
index 0f9ef6f3a8e0..84e9df96e0d9 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
@@ -22,7 +22,6 @@ public static void main(String[] args) {
             for (i = 0; i < n; i++) {
                 stack.push(sc.nextInt());
             }
-            sc.close();
             reverseStack(stack);
             System.out.println("The reversed stack is:");
             while (!stack.isEmpty()) {
diff --git a/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java b/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
index f58a56aa00c2..5f1190d67de0 100644
--- a/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
+++ b/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
@@ -30,12 +30,6 @@ public static void main(String[] args) {
                 arr[i] = sc.nextInt();
             }
 
-            try {
-                sc.close();
-            } catch (Exception e) {
-                System.out.println("Unable to close scanner" + e);
-            }
-
             // Find XOR of the 2 non repeating elements
             for (i = 0; i < n; i++) {
                 res ^= arr[i];
@@ -55,7 +49,6 @@ public static void main(String[] args) {
             }
 
             System.out.println("The two non repeating elements are " + num1 + " and " + num2);
-            sc.close();
         }
     }
     /*
diff --git a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
index e4a9cbba45de..a78bbbf34278 100644
--- a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
+++ b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
@@ -47,7 +47,6 @@ public static void main(String[] args) {
             for (i = 0; i < size2 - 1; i++) {
                 System.out.println(b[i]);
             }
-            s.close();
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/LinkListSort.java b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
index daddae486621..fdbfe3130e41 100644
--- a/src/main/java/com/thealgorithms/sorts/LinkListSort.java
+++ b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
@@ -8,13 +8,10 @@
 package com.thealgorithms.sorts;
 
 import java.util.Arrays;
-import java.util.Scanner;
 
 public class LinkListSort {
 
     public static boolean isSorted(int[] p, int option) {
-        try (Scanner sc = new Scanner(System.in)) {
-        }
         int[] a = p;
         // Array is taken as input from test class
         int[] b = p;

From 295e7436b1770fb3d0bdf02973caa1f58a4009bf Mon Sep 17 00:00:00 2001
From: Godwill Christopher <chrisgodswill115@gmail.com>
Date: Mon, 27 May 2024 01:06:06 -0600
Subject: [PATCH 0172/1338] style: enable `MethodName` in CheckStyle (#5182)

enabled: MethodName in CheckStyle
---
 checkstyle.xml                                |  2 +-
 .../thealgorithms/backtracking/PowerSum.java  |  8 ++--
 .../java/com/thealgorithms/ciphers/DES.java   |  6 +--
 .../datastructures/heaps/LeftistHeap.java     | 12 ++---
 .../datastructures/trees/GenericTree.java     | 12 ++---
 .../datastructures/trees/nearestRightKey.java |  4 +-
 .../dynamicprogramming/KadaneAlgorithm.java   |  2 +-
 .../LongestAlternatingSubsequence.java        |  4 +-
 .../LongestIncreasingSubsequence.java         |  2 +-
 .../LongestPalindromicSubsequence.java        |  6 +--
 .../LongestPalindromicSubstring.java          |  6 +--
 ...atrixChainRecursiveTopDownMemoisation.java | 10 ++---
 .../dynamicprogramming/WineProblem.java       | 20 ++++-----
 .../maths/SquareRootWithBabylonianMethod.java |  2 +-
 .../maths/TrinomialTriangle.java              |  8 ++--
 .../thealgorithms/misc/ThreeSumProblem.java   | 12 ++---
 .../com/thealgorithms/others/CountChar.java   |  2 +-
 .../java/com/thealgorithms/others/KMP.java    |  4 +-
 .../thealgorithms/others/KochSnowflake.java   | 18 ++++----
 .../com/thealgorithms/others/LineSweep.java   |  4 +-
 .../searches/BinarySearch2dArray.java         |  2 +-
 .../com/thealgorithms/searches/KMPSearch.java |  2 +-
 .../searches/OrderAgnosticBinarySearch.java   |  2 +-
 .../sorts/DutchNationalFlagSort.java          |  6 +--
 .../sorts/MergeSortNoExtraSpace.java          | 16 +++----
 .../datastructures/heaps/LeftistHeapTest.java | 10 ++---
 .../lists/SinglyLinkedListTest.java           |  6 +--
 .../StrassenMatrixMultiplicationTest.java     |  6 +--
 .../KnapsackMemoizationTest.java              |  6 +--
 .../LongestIncreasingSubsequenceTests.java    |  2 +-
 .../dynamicprogramming/UniquePathsTests.java  | 20 ++++-----
 .../com/thealgorithms/maths/AverageTest.java  |  8 ++--
 .../maths/PythagoreanTripleTest.java          |  2 +-
 .../SquareRootwithBabylonianMethodTest.java   |  8 ++--
 .../thealgorithms/others/CountCharTest.java   |  2 +-
 .../others/KadaneAlogrithmTest.java           | 16 +++----
 .../thealgorithms/others/LineSweepTest.java   |  2 +-
 ...SumOfDistinctSubarraysWithLengthKTest.java | 10 ++---
 .../scheduling/SJFSchedulingTest.java         |  8 ++--
 .../scheduling/SRTFSchedulingTest.java        |  2 +-
 .../searches/BinarySearch2dArrayTest.java     | 44 +++++++++----------
 .../thealgorithms/searches/KMPSearchTest.java | 20 ++++-----
 .../OrderAgnosticBinarySearchTest.java        | 24 +++++-----
 .../searches/RabinKarpAlgorithmTest.java      |  2 +-
 ...lumnWiseSorted2dArrayBinarySearchTest.java | 10 ++---
 .../sorts/BinaryInsertionSortTest.java        |  4 +-
 .../sorts/DutchNationalFlagSortTest.java      | 16 +++----
 .../sorts/IntrospectiveSortTest.java          | 12 ++---
 .../sorts/SelectionSortTest.java              |  4 +-
 .../thealgorithms/sorts/ShellSortTest.java    | 14 +++---
 .../thealgorithms/sorts/StrandSortTest.java   |  4 +-
 .../thealgorithms/sorts/WiggleSortTest.java   | 14 +++---
 .../strings/ReverseStringTest.java            |  2 +-
 53 files changed, 225 insertions(+), 225 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index b27e775f0f89..e5c8b7ed7a38 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -112,7 +112,7 @@
     <module name="LocalFinalVariableName"/>
     <!-- TODO <module name="LocalVariableName"/> -->
     <!-- TODO <module name="MemberName"/> -->
-    <!-- TODO <module name="MethodName"/> -->
+    <module name="MethodName"/>
     <module name="PackageName"/>
     <!-- TODO <module name="ParameterName"/> -->
     <module name="StaticVariableName"/>
diff --git a/src/main/java/com/thealgorithms/backtracking/PowerSum.java b/src/main/java/com/thealgorithms/backtracking/PowerSum.java
index 29e37a1ddde8..8c46fb1c924a 100644
--- a/src/main/java/com/thealgorithms/backtracking/PowerSum.java
+++ b/src/main/java/com/thealgorithms/backtracking/PowerSum.java
@@ -12,12 +12,12 @@ public class PowerSum {
     private int sum = 0;
 
     public int powSum(int N, int X) {
-        Sum(N, X, 1);
+        sum(N, X, 1);
         return count;
     }
 
     // here i is the natural number which will be raised by X and added in sum.
-    public void Sum(int N, int X, int i) {
+    public void sum(int N, int X, int i) {
         // if sum is equal to N that is one of our answer and count is increased.
         if (sum == N) {
             count++;
@@ -26,7 +26,7 @@ public void Sum(int N, int X, int i) {
           // result is less than N.
         else if (sum + power(i, X) <= N) {
             sum += power(i, X);
-            Sum(N, X, i + 1);
+            sum(N, X, i + 1);
             // backtracking and removing the number added last since no possible combination is
             // there with it.
             sum -= power(i, X);
@@ -34,7 +34,7 @@ else if (sum + power(i, X) <= N) {
         if (power(i, X) < N) {
             // calling the sum function with next natural number after backtracking if when it is
             // raised to X is still less than X.
-            Sum(N, X, i + 1);
+            sum(N, X, i + 1);
         }
     }
 
diff --git a/src/main/java/com/thealgorithms/ciphers/DES.java b/src/main/java/com/thealgorithms/ciphers/DES.java
index d601b61dcd34..5d27ca67015b 100644
--- a/src/main/java/com/thealgorithms/ciphers/DES.java
+++ b/src/main/java/com/thealgorithms/ciphers/DES.java
@@ -106,7 +106,7 @@ private String[] getSubkeys(String originalKey) {
         return subKeys;
     }
 
-    private String XOR(String a, String b) {
+    private String xOR(String a, String b) {
         int i;
         int l = a.length();
         StringBuilder xor = new StringBuilder();
@@ -143,7 +143,7 @@ private String feistel(String messageBlock, String key) {
         for (i = 0; i < 48; i++) {
             expandedKey.append(messageBlock.charAt(EXPANSION[i] - 1));
         }
-        String mixedKey = XOR(expandedKey.toString(), key);
+        String mixedKey = xOR(expandedKey.toString(), key);
         StringBuilder substitutedString = new StringBuilder();
 
         // Let us now use the s-boxes to transform each 6 bit (length here) block to 4 bits
@@ -175,7 +175,7 @@ private String encryptBlock(String message, String[] keys) {
         // Iterate 16 times
         for (i = 0; i < 16; i++) {
             String Ln = R0; // Previous Right block
-            String Rn = XOR(L0, feistel(R0, keys[i]));
+            String Rn = xOR(L0, feistel(R0, keys[i]));
             L0 = Ln;
             R0 = Rn;
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
index a48d99f89864..59cb9dfab700 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
@@ -91,7 +91,7 @@ public void insert(int a) {
     }
 
     // Returns and removes the minimum element in the heap
-    public int extract_min() {
+    public int extractMin() {
         // If is empty return -1
         if (isEmpty()) return -1;
 
@@ -101,17 +101,17 @@ public int extract_min() {
     }
 
     // Function returning a list of an in order traversal of the data structure
-    public ArrayList<Integer> in_order() {
+    public ArrayList<Integer> inOrder() {
         ArrayList<Integer> lst = new ArrayList<>();
-        in_order_aux(root, lst);
+        inOrderAux(root, lst);
         return new ArrayList<>(lst);
     }
 
     // Auxiliary function for in_order
-    private void in_order_aux(Node n, ArrayList<Integer> lst) {
+    private void inOrderAux(Node n, ArrayList<Integer> lst) {
         if (n == null) return;
-        in_order_aux(n.left, lst);
+        inOrderAux(n.left, lst);
         lst.add(n.element);
-        in_order_aux(n.right, lst);
+        inOrderAux(n.right, lst);
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java b/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java
index 39af10bac813..a2e36f33dd4b 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java
@@ -25,10 +25,10 @@ private static final class Node {
     private final Node root;
     public GenericTree() { // Constructor
         Scanner scn = new Scanner(System.in);
-        root = create_treeG(null, 0, scn);
+        root = createTreeG(null, 0, scn);
     }
 
-    private Node create_treeG(Node node, int childIndex, Scanner scanner) {
+    private Node createTreeG(Node node, int childIndex, Scanner scanner) {
         // display
         if (node == null) {
             System.out.println("Enter root's data");
@@ -41,7 +41,7 @@ private Node create_treeG(Node node, int childIndex, Scanner scanner) {
         System.out.println("number of children");
         int number = scanner.nextInt();
         for (int i = 0; i < number; i++) {
-            Node child = create_treeG(node, i, scanner);
+            Node child = createTreeG(node, i, scanner);
             node.child.add(child);
         }
         return node;
@@ -51,17 +51,17 @@ private Node create_treeG(Node node, int childIndex, Scanner scanner) {
      * Function to display the generic tree
      */
     public void display() { // Helper function
-        display_1(root);
+        display1(root);
     }
 
-    private void display_1(Node parent) {
+    private void display1(Node parent) {
         System.out.print(parent.data + "=>");
         for (int i = 0; i < parent.child.size(); i++) {
             System.out.print(parent.child.get(i).data + " ");
         }
         System.out.println(".");
         for (int i = 0; i < parent.child.size(); i++) {
-            display_1(parent.child.get(i));
+            display1(parent.child.get(i));
         }
     }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java b/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java
index 797e5e4d56b8..6c53666e5856 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java
@@ -8,7 +8,7 @@ private NearestRightKey() {
     }
 
     public static void main(String[] args) {
-        NRKTree root = BuildTree();
+        NRKTree root = buildTree();
         Scanner sc = new Scanner(System.in);
         System.out.print("Enter first number: ");
         int inputX0 = sc.nextInt();
@@ -17,7 +17,7 @@ public static void main(String[] args) {
         sc.close();
     }
 
-    public static NRKTree BuildTree() {
+    public static NRKTree buildTree() {
         int randomX = ThreadLocalRandom.current().nextInt(0, 100 + 1);
         NRKTree root = new NRKTree(null, null, randomX);
 
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
index 573d1217e09e..92cd656f6bbd 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
@@ -10,7 +10,7 @@ public final class KadaneAlgorithm {
     private KadaneAlgorithm() {
     }
 
-    public static boolean max_Sum(int[] a, int predicted_answer) {
+    public static boolean maxSum(int[] a, int predicted_answer) {
         int sum = a[0];
         int running_sum = 0;
         for (int k : a) {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
index 51a78a853e03..d6f9b2acf768 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
@@ -16,7 +16,7 @@ private LongestAlternatingSubsequence() {
     }
 
     /* Function to return longest alternating subsequence length*/
-    static int AlternatingLength(int[] arr, int n) {
+    static int alternatingLength(int[] arr, int n) {
         /*
 
                 las[i][0] = Length of the longest
@@ -68,6 +68,6 @@ public static void main(String[] args) {
         int[] arr = {10, 22, 9, 33, 49, 50, 31, 60};
         int n = arr.length;
         System.out.println("Length of Longest "
-            + "alternating subsequence is " + AlternatingLength(arr, n));
+            + "alternating subsequence is " + alternatingLength(arr, n));
     }
 }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
index 83c31989123f..7edfe1f5fde9 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
@@ -20,7 +20,7 @@ private static int upperBound(int[] ar, int l, int r, int key) {
         return r;
     }
 
-    public static int LIS(int[] array) {
+    public static int lis(int[] array) {
         int N = array.length;
         if (N == 0) {
             return 0;
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java
index 9dfc6883b16a..0b40d4559341 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java
@@ -12,14 +12,14 @@ public static void main(String[] args) {
         String a = "BBABCBCAB";
         String b = "BABCBAB";
 
-        String aLPS = LPS(a);
-        String bLPS = LPS(b);
+        String aLPS = lps(a);
+        String bLPS = lps(b);
 
         System.out.println(a + " => " + aLPS);
         System.out.println(b + " => " + bLPS);
     }
 
-    public static String LPS(String original) throws IllegalArgumentException {
+    public static String lps(String original) throws IllegalArgumentException {
         StringBuilder reverse = new StringBuilder(original);
         reverse = reverse.reverse();
         return recursiveLPS(original, reverse.toString());
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
index 2101ba702257..c6ae55919b82 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
@@ -11,14 +11,14 @@ public static void main(String[] args) {
         String a = "babad";
         String b = "cbbd";
 
-        String aLPS = LPS(a);
-        String bLPS = LPS(b);
+        String aLPS = lps(a);
+        String bLPS = lps(b);
 
         System.out.println(a + " => " + aLPS);
         System.out.println(b + " => " + bLPS);
     }
 
-    private static String LPS(String input) {
+    private static String lps(String input) {
         if (input == null || input.length() == 0) {
             return input;
         }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java
index 7d8015a56048..6c1c4cf54ffc 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java
@@ -10,7 +10,7 @@ public final class MatrixChainRecursiveTopDownMemoisation {
     private MatrixChainRecursiveTopDownMemoisation() {
     }
 
-    static int Memoized_Matrix_Chain(int[] p) {
+    static int memoizedMatrixChain(int[] p) {
         int n = p.length;
         int[][] m = new int[n][n];
         for (int i = 0; i < n; i++) {
@@ -18,10 +18,10 @@ static int Memoized_Matrix_Chain(int[] p) {
                 m[i][j] = Integer.MAX_VALUE;
             }
         }
-        return Lookup_Chain(m, p, 1, n - 1);
+        return lookupChain(m, p, 1, n - 1);
     }
 
-    static int Lookup_Chain(int[][] m, int[] p, int i, int j) {
+    static int lookupChain(int[][] m, int[] p, int i, int j) {
         if (i == j) {
             m[i][j] = 0;
             return m[i][j];
@@ -30,7 +30,7 @@ static int Lookup_Chain(int[][] m, int[] p, int i, int j) {
             return m[i][j];
         } else {
             for (int k = i; k < j; k++) {
-                int q = Lookup_Chain(m, p, i, k) + Lookup_Chain(m, p, k + 1, j) + (p[i - 1] * p[k] * p[j]);
+                int q = lookupChain(m, p, i, k) + lookupChain(m, p, k + 1, j) + (p[i - 1] * p[k] * p[j]);
                 if (q < m[i][j]) {
                     m[i][j] = q;
                 }
@@ -43,6 +43,6 @@ static int Lookup_Chain(int[][] m, int[] p, int i, int j) {
     // respectively output should be  Minimum number of multiplications is 38
     public static void main(String[] args) {
         int[] arr = {1, 2, 3, 4, 5};
-        System.out.println("Minimum number of multiplications is " + Memoized_Matrix_Chain(arr));
+        System.out.println("Minimum number of multiplications is " + memoizedMatrixChain(arr));
     }
 }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java b/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java
index 6d7f0b8a8036..0f5359f4d95e 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java
@@ -16,22 +16,22 @@ private WineProblem() {
 
     // Method 1: Using Recursion
     // Time Complexity=0(2^N) Space Complexity=Recursion extra space
-    public static int WPRecursion(int[] arr, int si, int ei) {
+    public static int wpRecursion(int[] arr, int si, int ei) {
         int n = arr.length;
         int year = (n - (ei - si + 1)) + 1;
         if (si == ei) {
             return arr[si] * year;
         }
 
-        int start = WPRecursion(arr, si + 1, ei) + arr[si] * year;
-        int end = WPRecursion(arr, si, ei - 1) + arr[ei] * year;
+        int start = wpRecursion(arr, si + 1, ei) + arr[si] * year;
+        int end = wpRecursion(arr, si, ei - 1) + arr[ei] * year;
 
         return Math.max(start, end);
     }
 
     // Method 2: Top-Down DP(Memoization)
     // Time Complexity=0(N*N) Space Complexity=0(N*N)+Recursion extra space
-    public static int WPTD(int[] arr, int si, int ei, int[][] strg) {
+    public static int wptd(int[] arr, int si, int ei, int[][] strg) {
         int n = arr.length;
         int year = (n - (ei - si + 1)) + 1;
         if (si == ei) {
@@ -41,8 +41,8 @@ public static int WPTD(int[] arr, int si, int ei, int[][] strg) {
         if (strg[si][ei] != 0) {
             return strg[si][ei];
         }
-        int start = WPTD(arr, si + 1, ei, strg) + arr[si] * year;
-        int end = WPTD(arr, si, ei - 1, strg) + arr[ei] * year;
+        int start = wptd(arr, si + 1, ei, strg) + arr[si] * year;
+        int end = wptd(arr, si, ei - 1, strg) + arr[ei] * year;
 
         int ans = Math.max(start, end);
 
@@ -53,7 +53,7 @@ public static int WPTD(int[] arr, int si, int ei, int[][] strg) {
 
     // Method 3: Bottom-Up DP(Tabulation)
     // Time Complexity=0(N*N/2)->0(N*N) Space Complexity=0(N*N)
-    public static int WPBU(int[] arr) {
+    public static int wpbu(int[] arr) {
         int n = arr.length;
         int[][] strg = new int[n][n];
 
@@ -76,9 +76,9 @@ public static int WPBU(int[] arr) {
 
     public static void main(String[] args) {
         int[] arr = {2, 3, 5, 1, 4};
-        System.out.println("Method 1: " + WPRecursion(arr, 0, arr.length - 1));
-        System.out.println("Method 2: " + WPTD(arr, 0, arr.length - 1, new int[arr.length][arr.length]));
-        System.out.println("Method 3: " + WPBU(arr));
+        System.out.println("Method 1: " + wpRecursion(arr, 0, arr.length - 1));
+        System.out.println("Method 2: " + wptd(arr, 0, arr.length - 1, new int[arr.length][arr.length]));
+        System.out.println("Method 3: " + wpbu(arr));
     }
 }
 // Memoization vs Tabulation : https://www.geeksforgeeks.org/tabulation-vs-memoization/
diff --git a/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java b/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java
index 90af556f8e23..2b071307e2bc 100644
--- a/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java
+++ b/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java
@@ -10,7 +10,7 @@ private SquareRootWithBabylonianMethod() {
      * @param num contains elements
      * @return the square root of num
      */
-    public static float square_Root(float num) {
+    public static float squareRoot(float num) {
         float a = num;
         float b = 1;
         double e = 0.000001;
diff --git a/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java b/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java
index c2a173000a78..877ef4227afc 100644
--- a/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java
+++ b/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java
@@ -11,7 +11,7 @@ public final class TrinomialTriangle {
     private TrinomialTriangle() {
     }
 
-    public static int TrinomialValue(int n, int k) {
+    public static int trinomialValue(int n, int k) {
         if (n == 0 && k == 0) {
             return 1;
         }
@@ -20,17 +20,17 @@ public static int TrinomialValue(int n, int k) {
             return 0;
         }
 
-        return (TrinomialValue(n - 1, k - 1) + TrinomialValue(n - 1, k) + TrinomialValue(n - 1, k + 1));
+        return (trinomialValue(n - 1, k - 1) + trinomialValue(n - 1, k) + trinomialValue(n - 1, k + 1));
     }
 
     public static void printTrinomial(int n) {
         for (int i = 0; i < n; i++) {
             for (int j = -i; j <= 0; j++) {
-                System.out.print(TrinomialValue(i, j) + " ");
+                System.out.print(trinomialValue(i, j) + " ");
             }
 
             for (int j = 1; j <= i; j++) {
-                System.out.print(TrinomialValue(i, j) + " ");
+                System.out.print(trinomialValue(i, j) + " ");
             }
 
             System.out.println();
diff --git a/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java b/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
index e5999313aa90..1c5f4a440532 100644
--- a/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
+++ b/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
@@ -24,13 +24,13 @@ public static void main(String[] args) {
             arr[i] = scan.nextInt();
         }
         ThreeSumProblem th = new ThreeSumProblem();
-        System.out.println("Brute Force Approach\n" + (th.BruteForce(arr, ts)) + "\n");
-        System.out.println("Two Pointer Approach\n" + (th.TwoPointer(arr, ts)) + "\n");
-        System.out.println("Hashmap Approach\n" + (th.Hashmap(arr, ts)));
+        System.out.println("Brute Force Approach\n" + (th.bruteForce(arr, ts)) + "\n");
+        System.out.println("Two Pointer Approach\n" + (th.twoPointer(arr, ts)) + "\n");
+        System.out.println("Hashmap Approach\n" + (th.hashMap(arr, ts)));
         scan.close();
     }
 
-    public List<List<Integer>> BruteForce(int[] nums, int target) {
+    public List<List<Integer>> bruteForce(int[] nums, int target) {
         List<List<Integer>> arr = new ArrayList<List<Integer>>();
 
         for (int i = 0; i < nums.length; i++) {
@@ -51,7 +51,7 @@ public List<List<Integer>> BruteForce(int[] nums, int target) {
         return arr;
     }
 
-    public List<List<Integer>> TwoPointer(int[] nums, int target) {
+    public List<List<Integer>> twoPointer(int[] nums, int target) {
         Arrays.sort(nums);
         List<List<Integer>> arr = new ArrayList<List<Integer>>();
         int start = 0;
@@ -81,7 +81,7 @@ public List<List<Integer>> TwoPointer(int[] nums, int target) {
         return new ArrayList<List<Integer>>(set);
     }
 
-    public List<List<Integer>> Hashmap(int[] nums, int target) {
+    public List<List<Integer>> hashMap(int[] nums, int target) {
         Arrays.sort(nums);
         Set<List<Integer>> ts = new HashSet<>();
         HashMap<Integer, Integer> hm = new HashMap<>();
diff --git a/src/main/java/com/thealgorithms/others/CountChar.java b/src/main/java/com/thealgorithms/others/CountChar.java
index 99441b83993d..ad858137726b 100644
--- a/src/main/java/com/thealgorithms/others/CountChar.java
+++ b/src/main/java/com/thealgorithms/others/CountChar.java
@@ -11,7 +11,7 @@ private CountChar() {
      * @return number of character in the specified string
      */
 
-    public static int CountCharacters(String str) {
+    public static int countCharacters(String str) {
         return str.replaceAll("\\s", "").length();
     }
 }
diff --git a/src/main/java/com/thealgorithms/others/KMP.java b/src/main/java/com/thealgorithms/others/KMP.java
index 1caa6b63cddc..7df5d1a8a5bd 100644
--- a/src/main/java/com/thealgorithms/others/KMP.java
+++ b/src/main/java/com/thealgorithms/others/KMP.java
@@ -13,11 +13,11 @@ private KMP() {
     public static void main(String[] args) {
         final String haystack = "AAAAABAAABA"; // This is the full string
         final String needle = "AAAA"; // This is the substring that we want to find
-        KMPmatcher(haystack, needle);
+        kmpMatcher(haystack, needle);
     }
 
     // find the starting index in string haystack[] that matches the search word P[]
-    public static void KMPmatcher(final String haystack, final String needle) {
+    public static void kmpMatcher(final String haystack, final String needle) {
         final int m = haystack.length();
         final int n = needle.length();
         final int[] pi = computePrefixFunction(needle);
diff --git a/src/main/java/com/thealgorithms/others/KochSnowflake.java b/src/main/java/com/thealgorithms/others/KochSnowflake.java
index ab426bb0ca9d..0e2600a7d72f 100644
--- a/src/main/java/com/thealgorithms/others/KochSnowflake.java
+++ b/src/main/java/com/thealgorithms/others/KochSnowflake.java
@@ -33,7 +33,7 @@ public static void main(String[] args) {
         ArrayList<Vector2> vectors = new ArrayList<Vector2>();
         vectors.add(new Vector2(0, 0));
         vectors.add(new Vector2(1, 0));
-        ArrayList<Vector2> result = Iterate(vectors, 1);
+        ArrayList<Vector2> result = iterate(vectors, 1);
 
         assert result.get(0).x == 0;
         assert result.get(0).y == 0;
@@ -54,7 +54,7 @@ public static void main(String[] args) {
         int imageWidth = 600;
         double offsetX = imageWidth / 10.;
         double offsetY = imageWidth / 3.7;
-        BufferedImage image = GetKochSnowflake(imageWidth, 5);
+        BufferedImage image = getKochSnowflake(imageWidth, 5);
 
         // The background should be white
         assert image.getRGB(0, 0) == new Color(255, 255, 255).getRGB();
@@ -80,10 +80,10 @@ public static void main(String[] args) {
      * @param steps The number of iterations.
      * @return The transformed vectors after the iteration-steps.
      */
-    public static ArrayList<Vector2> Iterate(ArrayList<Vector2> initialVectors, int steps) {
+    public static ArrayList<Vector2> iterate(ArrayList<Vector2> initialVectors, int steps) {
         ArrayList<Vector2> vectors = initialVectors;
         for (int i = 0; i < steps; i++) {
-            vectors = IterationStep(vectors);
+            vectors = iterationStep(vectors);
         }
 
         return vectors;
@@ -96,7 +96,7 @@ public static ArrayList<Vector2> Iterate(ArrayList<Vector2> initialVectors, int
      * @param steps The number of iterations.
      * @return The image of the rendered Koch snowflake.
      */
-    public static BufferedImage GetKochSnowflake(int imageWidth, int steps) {
+    public static BufferedImage getKochSnowflake(int imageWidth, int steps) {
         if (imageWidth <= 0) {
             throw new IllegalArgumentException("imageWidth should be greater than zero");
         }
@@ -111,8 +111,8 @@ public static BufferedImage GetKochSnowflake(int imageWidth, int steps) {
         initialVectors.add(vector2);
         initialVectors.add(vector3);
         initialVectors.add(vector1);
-        ArrayList<Vector2> vectors = Iterate(initialVectors, steps);
-        return GetImage(vectors, imageWidth, imageWidth);
+        ArrayList<Vector2> vectors = iterate(initialVectors, steps);
+        return getImage(vectors, imageWidth, imageWidth);
     }
 
     /**
@@ -125,7 +125,7 @@ public static BufferedImage GetKochSnowflake(int imageWidth, int steps) {
      * applied.
      * @return The transformed vectors after the iteration-step.
      */
-    private static ArrayList<Vector2> IterationStep(ArrayList<Vector2> vectors) {
+    private static ArrayList<Vector2> iterationStep(ArrayList<Vector2> vectors) {
         ArrayList<Vector2> newVectors = new ArrayList<Vector2>();
         for (int i = 0; i < vectors.size() - 1; i++) {
             Vector2 startVector = vectors.get(i);
@@ -149,7 +149,7 @@ private static ArrayList<Vector2> IterationStep(ArrayList<Vector2> vectors) {
      * @param imageHeight The height of the rendered image.
      * @return The image of the rendered edges.
      */
-    private static BufferedImage GetImage(ArrayList<Vector2> vectors, int imageWidth, int imageHeight) {
+    private static BufferedImage getImage(ArrayList<Vector2> vectors, int imageWidth, int imageHeight) {
         BufferedImage image = new BufferedImage(imageWidth, imageHeight, BufferedImage.TYPE_INT_RGB);
         Graphics2D g2d = image.createGraphics();
 
diff --git a/src/main/java/com/thealgorithms/others/LineSweep.java b/src/main/java/com/thealgorithms/others/LineSweep.java
index cb7f5214b0dc..946ba6edb475 100644
--- a/src/main/java/com/thealgorithms/others/LineSweep.java
+++ b/src/main/java/com/thealgorithms/others/LineSweep.java
@@ -20,7 +20,7 @@ private LineSweep() {
      *   param = ranges : Array of range[start,end]
      *   return Maximum Endpoint
      */
-    public static int FindMaximumEndPoint(int[][] ranges) {
+    public static int findMaximumEndPoint(int[][] ranges) {
         Arrays.sort(ranges, Comparator.comparingInt(a -> a[1]));
         return ranges[ranges.length - 1][1];
     }
@@ -32,7 +32,7 @@ public static int FindMaximumEndPoint(int[][] ranges) {
      */
     public static boolean isOverlap(int[][] ranges) {
 
-        int maximumEndPoint = FindMaximumEndPoint(ranges);
+        int maximumEndPoint = findMaximumEndPoint(ranges);
         Arrays.sort(ranges, Comparator.comparingInt(a -> a[0]));
         int[] numberLine = new int[maximumEndPoint + 2];
         for (int[] range : ranges) {
diff --git a/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java b/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
index 2794c4bde1d7..40b3cd0c20e3 100644
--- a/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
+++ b/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
@@ -12,7 +12,7 @@ public final class BinarySearch2dArray {
     private BinarySearch2dArray() {
     }
 
-    static int[] BinarySearch(int[][] arr, int target) {
+    static int[] binarySearch(int[][] arr, int target) {
         int rowCount = arr.length;
         int colCount = arr[0].length;
 
diff --git a/src/main/java/com/thealgorithms/searches/KMPSearch.java b/src/main/java/com/thealgorithms/searches/KMPSearch.java
index dd728d81bd23..38a4c74dee31 100644
--- a/src/main/java/com/thealgorithms/searches/KMPSearch.java
+++ b/src/main/java/com/thealgorithms/searches/KMPSearch.java
@@ -2,7 +2,7 @@
 
 class KMPSearch {
 
-    int KMPSearch(String pat, String txt) {
+    int kmpSearch(String pat, String txt) {
         int M = pat.length();
         int N = txt.length();
 
diff --git a/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java b/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
index bb593503ff61..8fb3f4f68986 100644
--- a/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
@@ -15,7 +15,7 @@ public final class OrderAgnosticBinarySearch {
     private OrderAgnosticBinarySearch() {
     }
 
-    static int BinSearchAlgo(int[] arr, int start, int end, int target) {
+    static int binSearchAlgo(int[] arr, int start, int end, int target) {
 
         // Checking whether the given array is ascending order
         boolean AscOrd = arr[start] < arr[end];
diff --git a/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java b/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java
index 7a3cdfa317f6..20b8f0ba1abc 100644
--- a/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java
@@ -13,14 +13,14 @@ public class DutchNationalFlagSort implements SortAlgorithm {
 
     @Override
     public <T extends Comparable<T>> T[] sort(T[] unsorted) {
-        return dutch_national_flag_sort(unsorted, unsorted[(int) Math.ceil((unsorted.length) / 2.0) - 1]);
+        return dutchNationalFlagSort(unsorted, unsorted[(int) Math.ceil((unsorted.length) / 2.0) - 1]);
     }
 
     public <T extends Comparable<T>> T[] sort(T[] unsorted, T intendedMiddle) {
-        return dutch_national_flag_sort(unsorted, intendedMiddle);
+        return dutchNationalFlagSort(unsorted, intendedMiddle);
     }
 
-    private <T extends Comparable<T>> T[] dutch_national_flag_sort(T[] arr, T intendedMiddle) {
+    private <T extends Comparable<T>> T[] dutchNationalFlagSort(T[] arr, T intendedMiddle) {
         int i = 0;
         int j = 0;
         int k = arr.length - 1;
diff --git a/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java b/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
index 803085f9f582..290c2df59c3d 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
@@ -10,21 +10,21 @@ public final class MergeSortNoExtraSpace {
     private MergeSortNoExtraSpace() {
     }
 
-    public static void call_merge_sort(int[] a, int n) {
+    public static void callMergeSort(int[] a, int n) {
         int maxele = Arrays.stream(a).max().getAsInt() + 1;
-        merge_sort(a, 0, n - 1, maxele);
+        mergeSort(a, 0, n - 1, maxele);
     }
 
-    public static void merge_sort(int[] a, int start, int end, int maxele) { // this function divides the array into 2 halves
+    public static void mergeSort(int[] a, int start, int end, int maxele) { // this function divides the array into 2 halves
         if (start < end) {
             int mid = (start + end) / 2;
-            merge_sort(a, start, mid, maxele);
-            merge_sort(a, mid + 1, end, maxele);
-            implement_merge_sort(a, start, mid, end, maxele);
+            mergeSort(a, start, mid, maxele);
+            mergeSort(a, mid + 1, end, maxele);
+            implementMergeSort(a, start, mid, end, maxele);
         }
     }
 
-    public static void implement_merge_sort(int[] a, int start, int mid, int end,
+    public static void implementMergeSort(int[] a, int start, int mid, int end,
         int maxele) { // implementation of mergesort
         int i = start;
         int j = mid + 1;
@@ -64,7 +64,7 @@ public static void main(String[] args) {
         for (int i = 0; i < n; i++) {
             a[i] = inp.nextInt();
         }
-        call_merge_sort(a, n);
+        callMergeSort(a, n);
         for (int i = 0; i < a.length; i++) {
             System.out.print(a[i] + " ");
         }
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java
index dfaba3911d0c..f4c4c548ffbf 100644
--- a/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java
@@ -14,14 +14,14 @@ void testLeftistHeap() {
         heap.insert(2);
         heap.insert(3);
         heap.insert(1);
-        heap.in_order();
-        Assertions.assertTrue(heap.in_order().toString().equals("[6, 2, 3, 1]"));
-        Assertions.assertTrue(heap.extract_min() == 1);
-        Assertions.assertTrue(heap.in_order().toString().equals("[6, 2, 3]"));
+        heap.inOrder();
+        Assertions.assertTrue(heap.inOrder().toString().equals("[6, 2, 3, 1]"));
+        Assertions.assertTrue(heap.extractMin() == 1);
+        Assertions.assertTrue(heap.inOrder().toString().equals("[6, 2, 3]"));
         heap.insert(8);
         heap.insert(12);
         heap.insert(4);
-        Assertions.assertTrue(heap.in_order().toString().equals("[8, 3, 12, 2, 6, 4]"));
+        Assertions.assertTrue(heap.inOrder().toString().equals("[8, 3, 12, 2, 6, 4]"));
         heap.clear();
         Assertions.assertTrue(heap.isEmpty());
     }
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
index 30bd727e0169..a47434083cdb 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
@@ -166,7 +166,7 @@ void reverseListTest() {
     }
     // This is Recursive Reverse List Test
     // Test to check whether the method reverseListRec() works fine
-    void RecursiveReverseList() {
+    void recursiveReverseList() {
         // Create a linked list: 1 -> 2 -> 3 -> 4 -> 5
         SinglyLinkedList list = createSampleList(5);
 
@@ -182,7 +182,7 @@ void RecursiveReverseList() {
     }
 
     @Test
-    void RecursiveReverseListNullPointer() {
+    void recursiveReverseListNullPointer() {
         // Create an empty linked list
         SinglyLinkedList list = new SinglyLinkedList();
         Node first = list.getHead();
@@ -195,7 +195,7 @@ void RecursiveReverseListNullPointer() {
     }
 
     @Test
-    void RecursiveReverseListTest() {
+    void recursiveReverseListTest() {
         // Create a linked list with values from 1 to 20
         SinglyLinkedList list = createSampleList(20);
 
diff --git a/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java b/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
index 6f4d4a09e442..ada3c23f4c65 100644
--- a/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
+++ b/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
@@ -12,7 +12,7 @@ class StrassenMatrixMultiplicationTest {
     // and has to be a Square Matrix
 
     @Test
-    public void StrassenMatrixMultiplicationTest2x2() {
+    public void strassenMatrixMultiplicationTest2x2() {
         int[][] A = {{1, 2}, {3, 4}};
         int[][] B = {{5, 6}, {7, 8}};
         int[][] expResult = {{19, 22}, {43, 50}};
@@ -21,7 +21,7 @@ public void StrassenMatrixMultiplicationTest2x2() {
     }
 
     @Test
-    void StrassenMatrixMultiplicationTest4x4() {
+    void strassenMatrixMultiplicationTest4x4() {
         int[][] A = {{1, 2, 5, 4}, {9, 3, 0, 6}, {4, 6, 3, 1}, {0, 2, 0, 6}};
         int[][] B = {{1, 0, 4, 1}, {1, 2, 0, 2}, {0, 3, 1, 3}, {1, 8, 1, 2}};
         int[][] expResult = {{7, 51, 13, 28}, {18, 54, 42, 27}, {11, 29, 20, 27}, {8, 52, 6, 16}};
@@ -30,7 +30,7 @@ void StrassenMatrixMultiplicationTest4x4() {
     }
 
     @Test
-    void StrassenMatrixMultiplicationTestNegetiveNumber4x4() {
+    void strassenMatrixMultiplicationTestNegativeNumber4x4() {
         int[][] A = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};
         int[][] B = {{1, -2, -3, 4}, {4, -3, -2, 1}, {5, -6, -7, 8}, {8, -7, -6, -5}};
         int[][] expResult = {{56, -54, -52, 10}, {128, -126, -124, 42}, {200, -198, -196, 74}, {272, -270, -268, 106}};
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java
index 34c0ab09225a..d220a2bb512e 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java
@@ -9,7 +9,7 @@ public class KnapsackMemoizationTest {
     KnapsackMemoization knapsackMemoization = new KnapsackMemoization();
 
     @Test
-    void Test1() {
+    void test1() {
         int[] weight = {1, 3, 4, 5};
         int[] value = {1, 4, 5, 7};
         int capacity = 10;
@@ -17,7 +17,7 @@ void Test1() {
     }
 
     @Test
-    void Test2() {
+    void test2() {
         int[] weight = {95, 4, 60, 32, 23, 72, 80, 62, 65, 46};
         int[] value = {55, 10, 47, 5, 4, 50, 8, 61, 85, 87};
         int capacity = 269;
@@ -25,7 +25,7 @@ void Test2() {
     }
 
     @Test
-    void Test3() {
+    void test3() {
         int[] weight = {10, 20, 30};
         int[] value = {60, 100, 120};
         int capacity = 50;
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java b/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java
index ea7abed50d89..5135105592a5 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java
@@ -42,7 +42,7 @@ private static Stream<Arguments> testCases() {
             {3, new int[] {1, 1, 2, 2, 2, 3, 3, 3, 3}},
         };
 
-        final List<IntArrayToInt> methods = Arrays.asList(LongestIncreasingSubsequence::LIS, LongestIncreasingSubsequence::findLISLen);
+        final List<IntArrayToInt> methods = Arrays.asList(LongestIncreasingSubsequence::lis, LongestIncreasingSubsequence::findLISLen);
 
         return Stream.of(testData).flatMap(input -> methods.stream().map(method -> Arguments.of(input[0], input[1], method)));
     }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java b/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java
index f4e32f65af22..386938d28ec9 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java
@@ -8,52 +8,52 @@
 public class UniquePathsTests {
 
     @Test
-    public void testUniquePaths_3x3() {
+    public void testUniquePaths3x3() {
         assertEquals(6, UniquePaths.uniquePaths(3, 3));
     }
 
     @Test
-    public void testUniquePaths_1x1() {
+    public void testUniquePaths1x1() {
         assertEquals(1, UniquePaths.uniquePaths(1, 1));
     }
 
     @Test
-    public void testUniquePaths_3x7() {
+    public void testUniquePaths3x7() {
         assertEquals(28, UniquePaths.uniquePaths(3, 7));
     }
 
     @Test
-    public void testUniquePaths_7x3() {
+    public void testUniquePaths7x3() {
         assertEquals(28, UniquePaths.uniquePaths(7, 3));
     }
 
     @Test
-    public void testUniquePaths_100x100() {
+    public void testUniquePaths100x100() {
         assertThrows(ArithmeticException.class, () -> UniquePaths.uniquePaths(100, 100));
     }
 
     @Test
-    public void testUniquePaths2_3x3() {
+    public void testUniquePathsII3x3() {
         assertEquals(6, UniquePaths.uniquePaths2(3, 3));
     }
 
     @Test
-    public void testUniquePaths2_1x1() {
+    public void testUniquePathsII1x1() {
         assertEquals(1, UniquePaths.uniquePaths2(1, 1));
     }
 
     @Test
-    public void testUniquePaths2_3x7() {
+    public void testUniquePathsII3x7() {
         assertEquals(28, UniquePaths.uniquePaths2(3, 7));
     }
 
     @Test
-    public void testUniquePaths2_7x3() {
+    public void testUniquePathsII7x3() {
         assertEquals(28, UniquePaths.uniquePaths2(7, 3));
     }
 
     @Test
-    public void testUniquePaths2_100x100() {
+    public void testUniquePathsII100x100() {
         assertThrows(ArithmeticException.class, () -> UniquePaths.uniquePaths2(100, 100));
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/AverageTest.java b/src/test/java/com/thealgorithms/maths/AverageTest.java
index 2008232c3b18..c5c751938f5d 100644
--- a/src/test/java/com/thealgorithms/maths/AverageTest.java
+++ b/src/test/java/com/thealgorithms/maths/AverageTest.java
@@ -8,25 +8,25 @@ public class AverageTest {
     private static final double SMALL_VALUE = 0.00001d;
 
     @Test
-    public void testAverage_double_12() {
+    public void testAverageDouble12() {
         double[] numbers = {3d, 6d, 9d, 12d, 15d, 18d, 21d};
         Assertions.assertEquals(12d, Average.average(numbers), SMALL_VALUE);
     }
 
     @Test
-    public void testAverage_double_20() {
+    public void testAverageDouble20() {
         double[] numbers = {5d, 10d, 15d, 20d, 25d, 30d, 35d};
         Assertions.assertEquals(20d, Average.average(numbers), SMALL_VALUE);
     }
 
     @Test
-    public void testAverage_double_4_5() {
+    public void testAverageDouble() {
         double[] numbers = {1d, 2d, 3d, 4d, 5d, 6d, 7d, 8d};
         Assertions.assertEquals(4.5d, Average.average(numbers), SMALL_VALUE);
     }
 
     @Test
-    public void testAverage_int_5() {
+    public void testAverageInt() {
         int[] numbers = {2, 4, 10};
         Assertions.assertEquals(5, Average.average(numbers));
     }
diff --git a/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java b/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java
index 1834c6e0fd1d..13ea58155dec 100644
--- a/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java
+++ b/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java
@@ -8,7 +8,7 @@
 public class PythagoreanTripleTest {
 
     @Test
-    public void Testpythagoreantriple() {
+    public void testPythagoreanTriple() {
         assertTrue(PythagoreanTriple.isPythagTriple(3, 4, 5));
         assertTrue(PythagoreanTriple.isPythagTriple(6, 8, 10));
         assertTrue(PythagoreanTriple.isPythagTriple(9, 12, 15));
diff --git a/src/test/java/com/thealgorithms/maths/SquareRootwithBabylonianMethodTest.java b/src/test/java/com/thealgorithms/maths/SquareRootwithBabylonianMethodTest.java
index 3d13e43665af..77446d30df32 100644
--- a/src/test/java/com/thealgorithms/maths/SquareRootwithBabylonianMethodTest.java
+++ b/src/test/java/com/thealgorithms/maths/SquareRootwithBabylonianMethodTest.java
@@ -7,21 +7,21 @@ public class SquareRootwithBabylonianMethodTest {
 
     @Test
     void testfor4() {
-        Assertions.assertEquals(2, SquareRootWithBabylonianMethod.square_Root(4));
+        Assertions.assertEquals(2, SquareRootWithBabylonianMethod.squareRoot(4));
     }
 
     @Test
     void testfor1() {
-        Assertions.assertEquals(1, SquareRootWithBabylonianMethod.square_Root(1));
+        Assertions.assertEquals(1, SquareRootWithBabylonianMethod.squareRoot(1));
     }
 
     @Test
     void testfor2() {
-        Assertions.assertEquals(1.4142135381698608, SquareRootWithBabylonianMethod.square_Root(2));
+        Assertions.assertEquals(1.4142135381698608, SquareRootWithBabylonianMethod.squareRoot(2));
     }
 
     @Test
     void testfor625() {
-        Assertions.assertEquals(25, SquareRootWithBabylonianMethod.square_Root(625));
+        Assertions.assertEquals(25, SquareRootWithBabylonianMethod.squareRoot(625));
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/CountCharTest.java b/src/test/java/com/thealgorithms/others/CountCharTest.java
index 660f212118d2..382ba4246400 100644
--- a/src/test/java/com/thealgorithms/others/CountCharTest.java
+++ b/src/test/java/com/thealgorithms/others/CountCharTest.java
@@ -11,6 +11,6 @@ void testCountCharacters() {
         String input = "12345";
         int expectedValue = 5;
 
-        assertEquals(expectedValue, CountChar.CountCharacters(input));
+        assertEquals(expectedValue, CountChar.countCharacters(input));
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java b/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java
index e5c0597d94c0..25b211657c5d 100644
--- a/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java
+++ b/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java
@@ -10,48 +10,48 @@ public class KadaneAlogrithmTest {
     @Test
     void testForOneElement() {
         int[] a = {-1};
-        assertTrue(KadaneAlgorithm.max_Sum(a, -1));
+        assertTrue(KadaneAlgorithm.maxSum(a, -1));
     }
 
     @Test
     void testForTwoElements() {
         int[] a = {-2, 1};
-        assertTrue(KadaneAlgorithm.max_Sum(a, 1));
+        assertTrue(KadaneAlgorithm.maxSum(a, 1));
     }
 
     @Test
     void testForThreeElements() {
         int[] a = {5, 3, 12};
-        assertTrue(KadaneAlgorithm.max_Sum(a, 20));
+        assertTrue(KadaneAlgorithm.maxSum(a, 20));
     }
 
     @Test
     void testForFourElements() {
         int[] a = {-1, -3, -7, -4};
-        assertTrue(KadaneAlgorithm.max_Sum(a, -1));
+        assertTrue(KadaneAlgorithm.maxSum(a, -1));
     }
 
     @Test
     void testForFiveElements() {
         int[] a = {4, 5, 3, 0, 2};
-        assertTrue(KadaneAlgorithm.max_Sum(a, 14));
+        assertTrue(KadaneAlgorithm.maxSum(a, 14));
     }
 
     @Test
     void testForSixElements() {
         int[] a = {-43, -45, 47, 12, 87, -13};
-        assertTrue(KadaneAlgorithm.max_Sum(a, 146));
+        assertTrue(KadaneAlgorithm.maxSum(a, 146));
     }
 
     @Test
     void testForSevenElements() {
         int[] a = {9, 8, 2, 23, 13, 6, 7};
-        assertTrue(KadaneAlgorithm.max_Sum(a, 68));
+        assertTrue(KadaneAlgorithm.maxSum(a, 68));
     }
 
     @Test
     void testForEightElements() {
         int[] a = {9, -5, -5, -2, 4, 5, 0, 1};
-        assertTrue(KadaneAlgorithm.max_Sum(a, 10));
+        assertTrue(KadaneAlgorithm.maxSum(a, 10));
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/LineSweepTest.java b/src/test/java/com/thealgorithms/others/LineSweepTest.java
index af23885b4a7e..6bf6ef5b3002 100644
--- a/src/test/java/com/thealgorithms/others/LineSweepTest.java
+++ b/src/test/java/com/thealgorithms/others/LineSweepTest.java
@@ -25,6 +25,6 @@ void testForOverlapWhenEndAEqualsStartBAndViceVersa() {
     @Test
     void testForMaximumEndPoint() {
         int[][] arr = {{10, 20}, {1, 100}, {14, 16}, {1, 8}};
-        assertEquals(100, LineSweep.FindMaximumEndPoint(arr));
+        assertEquals(100, LineSweep.findMaximumEndPoint(arr));
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java b/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
index 26c57a1c9f75..a8e168ffa13a 100644
--- a/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
+++ b/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
@@ -6,27 +6,27 @@
 
 public class MaximumSumOfDistinctSubarraysWithLengthKTest {
     @Test
-    public void SampleTestCase1() {
+    public void sampleTestCase1() {
         assertEquals(15, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(3, 1, 5, 4, 2, 9, 9, 9));
     }
 
     @Test
-    public void SampleTestCase2() {
+    public void sampleTestCase2() {
         assertEquals(0, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(3, 4, 4, 4));
     }
 
     @Test
-    public void SampleTestCase3() {
+    public void sampleTestCase3() {
         assertEquals(12, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(3, 9, 9, 9, 1, 2, 3));
     }
 
     @Test
-    public void EdgeCase1() {
+    public void edgeCase1() {
         assertEquals(0, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(0, 9, 9, 9));
     }
 
     @Test
-    public void EdgeCase2() {
+    public void edgeCase2() {
         assertEquals(0, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(5, 9, 9, 9));
     }
 }
diff --git a/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java
index 41cbe75afbb5..aab5c64c847f 100644
--- a/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java
@@ -74,7 +74,7 @@ void scheduling() {
     }
 
     @Test
-    void schedulingOf_TwoProcesses() {
+    void schedulingOfTwoProcesses() {
         initialisation0();
         SJFScheduling a = new SJFScheduling(process);
         a.scheduleProcesses();
@@ -83,7 +83,7 @@ void schedulingOf_TwoProcesses() {
     }
 
     @Test
-    void schedulingOfA_ShortestJobArrivingLast() {
+    void schedulingOfAShortestJobArrivingLast() {
         initialisation2();
         SJFScheduling a = new SJFScheduling(process);
         a.scheduleProcesses();
@@ -92,7 +92,7 @@ void schedulingOfA_ShortestJobArrivingLast() {
         assertEquals("2", a.schedule.get(2));
     }
     @Test
-    void scheduling_WithProcessesNotComingBackToBack() {
+    void schedulingWithProcessesNotComingBackToBack() {
         initialisation3();
         SJFScheduling a = new SJFScheduling(process);
         a.scheduleProcesses();
@@ -101,7 +101,7 @@ void scheduling_WithProcessesNotComingBackToBack() {
         assertEquals("3", a.schedule.get(2));
     }
     @Test
-    void schedulingOf_nothing() {
+    void schedulingOfNothing() {
         process = new ArrayList<>();
         SJFScheduling a = new SJFScheduling(process);
         a.scheduleProcesses();
diff --git a/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java
index 0cfe3d34f0ec..9cec31130164 100644
--- a/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java
@@ -19,7 +19,7 @@ public void initialization() {
     }
 
     @Test
-    public void Constructor() {
+    public void constructor() {
         initialization();
         SRTFScheduling s = new SRTFScheduling(processes);
         assertEquals(3, s.processes.get(0).getBurstTime());
diff --git a/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java b/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java
index ec834d788589..18f0afc6a0a6 100644
--- a/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java
+++ b/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java
@@ -10,11 +10,11 @@ public class BinarySearch2dArrayTest {
 
     @Test
     // valid test case
-    public void BinarySearch2dArrayTestMiddle() {
+    public void binarySearch2dArrayTestMiddle() {
         int[][] arr = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
         int target = 6;
 
-        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(1, ans[0]);
         assertEquals(1, ans[1]);
@@ -22,11 +22,11 @@ public void BinarySearch2dArrayTestMiddle() {
 
     @Test
     // valid test case
-    public void BinarySearch2dArrayTestMiddleSide() {
+    public void binarySearch2dArrayTestMiddleSide() {
         int[][] arr = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
         int target = 8;
 
-        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(1, ans[0]);
         assertEquals(3, ans[1]);
@@ -34,11 +34,11 @@ public void BinarySearch2dArrayTestMiddleSide() {
 
     @Test
     // valid test case
-    public void BinarySearch2dArrayTestUpper() {
+    public void binarySearch2dArrayTestUpper() {
         int[][] arr = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
         int target = 2;
 
-        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(0, ans[0]);
         assertEquals(1, ans[1]);
@@ -46,11 +46,11 @@ public void BinarySearch2dArrayTestUpper() {
 
     @Test
     // valid test case
-    public void BinarySearch2dArrayTestUpperSide() {
+    public void binarySearch2dArrayTestUpperSide() {
         int[][] arr = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
         int target = 1;
 
-        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(0, ans[0]);
         assertEquals(0, ans[1]);
@@ -58,11 +58,11 @@ public void BinarySearch2dArrayTestUpperSide() {
 
     @Test
     // valid test case
-    public void BinarySearch2dArrayTestLower() {
+    public void binarySearch2dArrayTestLower() {
         int[][] arr = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
         int target = 10;
 
-        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(2, ans[0]);
         assertEquals(1, ans[1]);
@@ -70,11 +70,11 @@ public void BinarySearch2dArrayTestLower() {
 
     @Test
     // valid test case
-    public void BinarySearch2dArrayTestLowerSide() {
+    public void binarySearch2dArrayTestLowerSide() {
         int[][] arr = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
         int target = 11;
 
-        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(2, ans[0]);
         assertEquals(2, ans[1]);
@@ -82,11 +82,11 @@ public void BinarySearch2dArrayTestLowerSide() {
 
     @Test
     // valid test case
-    public void BinarySearch2dArrayTestNotFound() {
+    public void binarySearch2dArrayTestNotFound() {
         int[][] arr = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
         int target = 101;
 
-        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(-1, ans[0]);
         assertEquals(-1, ans[1]);
@@ -96,13 +96,13 @@ public void BinarySearch2dArrayTestNotFound() {
      * Test if the method works with input arrays consisting only of one row.
      */
     @Test
-    public void BinarySearch2dArrayTestOneRow() {
+    public void binarySearch2dArrayTestOneRow() {
         int[][] arr = {{1, 2, 3, 4}};
         int target = 2;
 
         // Assert that the requirement, that the array only has one row, is fulfilled.
         assertEquals(arr.length, 1);
-        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(0, ans[0]);
         assertEquals(1, ans[1]);
@@ -112,13 +112,13 @@ public void BinarySearch2dArrayTestOneRow() {
      * Test if the method works with the target in the middle of the input.
      */
     @Test
-    public void BinarySearch2dArrayTestTargetInMiddle() {
+    public void binarySearch2dArrayTestTargetInMiddle() {
         int[][] arr = {{1, 2, 3, 4, 5}, {6, 7, 8, 9, 10}, {11, 12, 13, 14, 15}};
         int target = 8;
         // Assert that the requirement, that the target is in the middle row and middle column, is
         // fulfilled.
         assertEquals(arr[arr.length / 2][arr[0].length / 2], target);
-        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(1, ans[0]);
         assertEquals(2, ans[1]);
@@ -129,7 +129,7 @@ public void BinarySearch2dArrayTestTargetInMiddle() {
      * in the row above the middle row.
      */
     @Test
-    public void BinarySearch2dArrayTestTargetAboveMiddleRowInMiddleColumn() {
+    public void binarySearch2dArrayTestTargetAboveMiddleRowInMiddleColumn() {
         int[][] arr = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
         int target = 3;
 
@@ -137,7 +137,7 @@ public void BinarySearch2dArrayTestTargetAboveMiddleRowInMiddleColumn() {
         // in an array with an even number of columns, and on the row "above" the middle row.
         assertEquals(arr[0].length % 2, 0);
         assertEquals(arr[arr.length / 2 - 1][arr[0].length / 2], target);
-        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(0, ans[0]);
         assertEquals(2, ans[1]);
@@ -147,11 +147,11 @@ public void BinarySearch2dArrayTestTargetAboveMiddleRowInMiddleColumn() {
      * Test if the method works with an empty array.
      */
     @Test
-    public void BinarySearch2dArrayTestEmptyArray() {
+    public void binarySearch2dArrayTestEmptyArray() {
         int[][] arr = {};
         int target = 5;
 
         // Assert that an empty array is not valid input for the method.
-        assertThrows(ArrayIndexOutOfBoundsException.class, () -> BinarySearch2dArray.BinarySearch(arr, target));
+        assertThrows(ArrayIndexOutOfBoundsException.class, () -> BinarySearch2dArray.binarySearch(arr, target));
     }
 }
diff --git a/src/test/java/com/thealgorithms/searches/KMPSearchTest.java b/src/test/java/com/thealgorithms/searches/KMPSearchTest.java
index ab6a14fbb604..cb804ac6a6a3 100644
--- a/src/test/java/com/thealgorithms/searches/KMPSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/KMPSearchTest.java
@@ -8,55 +8,55 @@ class KMPSearchTest {
 
     @Test
     // valid test case
-    public void KMPSearchTestLast() {
+    public void kmpSearchTestLast() {
         String txt = "ABABDABACDABABCABAB";
         String pat = "ABABCABAB";
         KMPSearch kmpSearch = new KMPSearch();
-        int value = kmpSearch.KMPSearch(pat, txt);
+        int value = kmpSearch.kmpSearch(pat, txt);
         System.out.println(value);
         assertEquals(value, 10);
     }
 
     @Test
     // valid test case
-    public void KMPSearchTestFront() {
+    public void kmpSearchTestFront() {
         String txt = "AAAAABAAABA";
         String pat = "AAAA";
         KMPSearch kmpSearch = new KMPSearch();
-        int value = kmpSearch.KMPSearch(pat, txt);
+        int value = kmpSearch.kmpSearch(pat, txt);
         System.out.println(value);
         assertEquals(value, 0);
     }
 
     @Test
     // valid test case
-    public void KMPSearchTestMiddle() {
+    public void kmpSearchTestMiddle() {
         String txt = "AAACAAAAAC";
         String pat = "AAAA";
         KMPSearch kmpSearch = new KMPSearch();
-        int value = kmpSearch.KMPSearch(pat, txt);
+        int value = kmpSearch.kmpSearch(pat, txt);
         System.out.println(value);
         assertEquals(value, 4);
     }
 
     @Test
     // valid test case
-    public void KMPSearchTestNotFound() {
+    public void kmpSearchTestNotFound() {
         String txt = "AAABAAAA";
         String pat = "AAAA";
         KMPSearch kmpSearch = new KMPSearch();
-        int value = kmpSearch.KMPSearch(pat, txt);
+        int value = kmpSearch.kmpSearch(pat, txt);
         System.out.println(value);
         assertEquals(value, 4);
     }
 
     @Test
     // not valid test case
-    public void KMPSearchTest4() {
+    public void kmpSearchTest4() {
         String txt = "AABAAA";
         String pat = "AAAA";
         KMPSearch kmpSearch = new KMPSearch();
-        int value = kmpSearch.KMPSearch(pat, txt);
+        int value = kmpSearch.kmpSearch(pat, txt);
         System.out.println(value);
         assertEquals(value, -1);
     }
diff --git a/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java
index c19adaa1260c..03502eec00d1 100644
--- a/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java
@@ -7,9 +7,9 @@
 public class OrderAgnosticBinarySearchTest {
     @Test
     // valid Test Case
-    public void ElementInMiddle() {
+    public void elementInMiddle() {
         int[] arr = {10, 20, 30, 40, 50};
-        int answer = OrderAgnosticBinarySearch.BinSearchAlgo(arr, 0, arr.length - 1, 30);
+        int answer = OrderAgnosticBinarySearch.binSearchAlgo(arr, 0, arr.length - 1, 30);
         System.out.println(answer);
         int expected = 2;
         assertEquals(expected, answer);
@@ -17,9 +17,9 @@ public void ElementInMiddle() {
 
     @Test
     // valid Test Case
-    public void RightHalfDescOrder() {
+    public void rightHalfDescOrder() {
         int[] arr = {50, 40, 30, 20, 10};
-        int answer = OrderAgnosticBinarySearch.BinSearchAlgo(arr, 0, arr.length - 1, 10);
+        int answer = OrderAgnosticBinarySearch.binSearchAlgo(arr, 0, arr.length - 1, 10);
         System.out.println(answer);
         int expected = 4;
         assertEquals(expected, answer);
@@ -27,9 +27,9 @@ public void RightHalfDescOrder() {
 
     @Test
     // valid test case
-    public void LeftHalfDescOrder() {
+    public void leftHalfDescOrder() {
         int[] arr = {50, 40, 30, 20, 10};
-        int answer = OrderAgnosticBinarySearch.BinSearchAlgo(arr, 0, arr.length - 1, 50);
+        int answer = OrderAgnosticBinarySearch.binSearchAlgo(arr, 0, arr.length - 1, 50);
         System.out.println(answer);
         int expected = 0;
         assertEquals(expected, answer);
@@ -37,9 +37,9 @@ public void LeftHalfDescOrder() {
 
     @Test
     // valid test case
-    public void RightHalfAscOrder() {
+    public void rightHalfAscOrder() {
         int[] arr = {10, 20, 30, 40, 50};
-        int answer = OrderAgnosticBinarySearch.BinSearchAlgo(arr, 0, arr.length - 1, 50);
+        int answer = OrderAgnosticBinarySearch.binSearchAlgo(arr, 0, arr.length - 1, 50);
         System.out.println(answer);
         int expected = 4;
         assertEquals(expected, answer);
@@ -47,9 +47,9 @@ public void RightHalfAscOrder() {
 
     @Test
     // valid test case
-    public void LeftHalfAscOrder() {
+    public void leftHalfAscOrder() {
         int[] arr = {10, 20, 30, 40, 50};
-        int answer = OrderAgnosticBinarySearch.BinSearchAlgo(arr, 0, arr.length - 1, 10);
+        int answer = OrderAgnosticBinarySearch.binSearchAlgo(arr, 0, arr.length - 1, 10);
         System.out.println(answer);
         int expected = 0;
         assertEquals(expected, answer);
@@ -57,9 +57,9 @@ public void LeftHalfAscOrder() {
 
     @Test
     // valid test case
-    public void ElementNotFound() {
+    public void elementNotFound() {
         int[] arr = {10, 20, 30, 40, 50};
-        int answer = OrderAgnosticBinarySearch.BinSearchAlgo(arr, 0, arr.length - 1, 100);
+        int answer = OrderAgnosticBinarySearch.binSearchAlgo(arr, 0, arr.length - 1, 100);
         System.out.println(answer);
         int expected = -1;
         assertEquals(expected, answer);
diff --git a/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java b/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java
index a8dc96e91998..40e1acce9c3a 100644
--- a/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java
@@ -9,7 +9,7 @@ class RabinKarpAlgorithmTest {
 
     @ParameterizedTest
     @CsvSource({"This is an example for rabin karp algorithmn, algorithmn, 101", "AAABBDDG, AAA, 137", "AAABBCCBB, BBCC, 101", "AAABBCCBB, BBCC, 131", "AAAABBBBCCC, CCC, 41", "ABCBCBCAAB, AADB, 293", "Algorithm The Algorithm, Algorithm, 101"})
-    void RabinKarpAlgorithmTestExample(String txt, String pat, int q) {
+    void rabinKarpAlgorithmTestExample(String txt, String pat, int q) {
         int indexFromOurAlgorithm = RabinKarpAlgorithm.search(pat, txt, q);
         int indexFromLinearSearch = txt.indexOf(pat);
         assertEquals(indexFromOurAlgorithm, indexFromLinearSearch);
diff --git a/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java
index e706a58fafbe..39ac5bf037ea 100644
--- a/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java
@@ -37,7 +37,7 @@ public void rowColumnSorted2dArrayBinarySearchTestSide() {
     }
 
     @Test
-    public void rowColumnSorted2dArray_BinarySearchTestUpper() {
+    public void rowColumnSorted2dArrayBinarySearchTestUpper() {
         Integer[][] arr = {
             {10, 20, 30, 40},
             {15, 25, 35, 45},
@@ -52,7 +52,7 @@ public void rowColumnSorted2dArray_BinarySearchTestUpper() {
     }
 
     @Test
-    public void rowColumnSorted2dArray_BinarySearchTestUpperSide() {
+    public void rowColumnSorted2dArrayBinarySearchTestUpperSide() {
         Integer[][] arr = {
             {10, 20, 30, 40},
             {15, 25, 35, 45},
@@ -67,7 +67,7 @@ public void rowColumnSorted2dArray_BinarySearchTestUpperSide() {
     }
 
     @Test
-    public void rowColumnSorted2dArray_BinarySearchTestLower() {
+    public void rowColumnSorted2dArrayBinarySearchTestLower() {
         Integer[][] arr = {
             {10, 20, 30, 40},
             {15, 25, 35, 45},
@@ -82,7 +82,7 @@ public void rowColumnSorted2dArray_BinarySearchTestLower() {
     }
 
     @Test
-    public void rowColumnSorted2dArray_BinarySearchTestLowerSide() {
+    public void rowColumnSorted2dArrayBinarySearchTestLowerSide() {
         Integer[][] arr = {
             {10, 20, 30, 40},
             {15, 25, 35, 45},
@@ -97,7 +97,7 @@ public void rowColumnSorted2dArray_BinarySearchTestLowerSide() {
     }
 
     @Test
-    public void rowColumnSorted2dArray_BinarySearchTestNotFound() {
+    public void rowColumnSorted2dArrayBinarySearchTestNotFound() {
         Integer[][] arr = {
             {10, 20, 30, 40},
             {15, 25, 35, 45},
diff --git a/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java b/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
index 349c3a2b9bba..2c355cee01b8 100644
--- a/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
@@ -10,7 +10,7 @@ class BinaryInsertionSortTest {
 
     @Test
     // valid test case
-    public void BinaryInsertionSortTestNonDuplicate() {
+    public void binaryInsertionSortTestNonDuplicate() {
         int[] array = {1, 0, 2, 5, 3, 4, 9, 8, 10, 6, 7};
         int[] expResult = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
         int[] actResult = BIS.binaryInsertSort(array);
@@ -18,7 +18,7 @@ public void BinaryInsertionSortTestNonDuplicate() {
     }
 
     @Test
-    public void BinaryInsertionSortTestDuplicate() {
+    public void binaryInsertionSortTestDuplicate() {
         int[] array = {1, 1, 1, 5, 9, 8, 7, 2, 6};
         int[] expResult = {1, 1, 1, 2, 5, 6, 7, 8, 9};
         int[] actResult = BIS.binaryInsertSort(array);
diff --git a/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java b/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java
index 8d3a4ac4349c..c7581e7c8f7b 100644
--- a/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java
@@ -11,7 +11,7 @@ public class DutchNationalFlagSortTest {
       1 will be used as intended middle.
       Partitions on the result array: [ smaller than 1 , equal 1, greater than 1]
      */
-    void DNFSTestOdd() {
+    void testOddDnfs() {
         Integer[] integers = {1, 3, 1, 4, 0};
         Integer[] integersResult = {0, 1, 1, 4, 3};
         DutchNationalFlagSort dutchNationalFlagSort = new DutchNationalFlagSort();
@@ -24,7 +24,7 @@ void DNFSTestOdd() {
       3 will be used as intended middle.
       Partitions on the result array: [ smaller than 3 , equal 3, greater than 3]
      */
-    void DNFSTestEven() {
+    void testEvenDnfs() {
         Integer[] integers = {8, 1, 3, 1, 4, 0};
         Integer[] integersResult = {0, 1, 1, 3, 4, 8};
         DutchNationalFlagSort dutchNationalFlagSort = new DutchNationalFlagSort();
@@ -37,7 +37,7 @@ void DNFSTestEven() {
       "b" will be used as intended middle.
       Partitions on the result array: [ smaller than b , equal b, greater than b]
      */
-    void DNFSTestEvenStrings() {
+    void testEvenStringsDnfs() {
         String[] strings = {"a", "d", "b", "s", "e", "e"};
         String[] stringsResult = {"a", "b", "s", "e", "e", "d"};
         DutchNationalFlagSort dutchNationalFlagSort = new DutchNationalFlagSort();
@@ -50,7 +50,7 @@ void DNFSTestEvenStrings() {
       "b" will be used as intended middle.
       Partitions on the result array: [ smaller than b , equal b, greater than b]
      */
-    void DNFSTestOddStrings() {
+    void testOddStringsDnfs() {
         String[] strings = {"a", "d", "b", "s", "e"};
         String[] stringsResult = {"a", "b", "s", "e", "d"};
         DutchNationalFlagSort dutchNationalFlagSort = new DutchNationalFlagSort();
@@ -63,7 +63,7 @@ void DNFSTestOddStrings() {
       0 will be used as intended middle.
       Partitions on the result array: [ smaller than 0 , equal 0, greater than 0]
      */
-    void DNFSTestOddMidGiven() {
+    void testOddMidGivenDnfs() {
         Integer[] integers = {1, 3, 1, 4, 0};
         Integer[] integersResult = {0, 1, 4, 3, 1};
         DutchNationalFlagSort dutchNationalFlagSort = new DutchNationalFlagSort();
@@ -76,7 +76,7 @@ void DNFSTestOddMidGiven() {
       4 will be used as intended middle.
       Partitions on the result array: [ smaller than 4 , equal 4, greater than 4]
      */
-    void DNFSTestEvenMidGiven() {
+    void testEvenMidGivenDnfs() {
         Integer[] integers = {8, 1, 3, 1, 4, 0};
         Integer[] integersResult = {0, 1, 3, 1, 4, 8};
         DutchNationalFlagSort dutchNationalFlagSort = new DutchNationalFlagSort();
@@ -89,7 +89,7 @@ void DNFSTestEvenMidGiven() {
       "s" will be used as intended middle.
       Partitions on the result array: [ smaller than s , equal s, greater than s]
      */
-    void DNFSTestEvenStringsMidGiven() {
+    void testEvenStringsMidGivenDnfs() {
         String[] strings = {"a", "d", "b", "s", "e", "e"};
         String[] stringsResult = {"a", "d", "b", "e", "e", "s"};
         DutchNationalFlagSort dutchNationalFlagSort = new DutchNationalFlagSort();
@@ -102,7 +102,7 @@ void DNFSTestEvenStringsMidGiven() {
       "e" will be used as intended middle.
       Partitions on the result array: [ smaller than e , equal e, greater than e]
      */
-    void DNFSTestOddStringsMidGiven() {
+    void testOddStringsMidGivenDnfs() {
         String[] strings = {"a", "d", "b", "s", "e"};
         String[] stringsResult = {"a", "d", "b", "e", "s"};
         DutchNationalFlagSort dutchNationalFlagSort = new DutchNationalFlagSort();
diff --git a/src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java b/src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java
index 54179e12049c..a5c6905f7514 100644
--- a/src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java
@@ -8,7 +8,7 @@
 public class IntrospectiveSortTest {
     @Test
     // valid test case
-    public void StrandSortNonDuplicateTest() {
+    public void strandSortNonDuplicateTest() {
         Integer[] expectedArray = {1, 2, 3, 4, 5};
         Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
         assertArrayEquals(expectedArray, actualList);
@@ -16,7 +16,7 @@ public void StrandSortNonDuplicateTest() {
 
     @Test
     // valid test case
-    public void StrandSortDuplicateTest() {
+    public void strandSortDuplicateTest() {
         Integer[] expectedArray = {2, 2, 2, 5, 7};
         Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
         assertArrayEquals(expectedArray, actualList);
@@ -24,7 +24,7 @@ public void StrandSortDuplicateTest() {
 
     @Test
     // valid test case
-    public void StrandSortEmptyTest() {
+    public void strandSortEmptyTest() {
         Integer[] expectedArray = {};
         Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
         assertArrayEquals(expectedArray, actualList);
@@ -32,14 +32,14 @@ public void StrandSortEmptyTest() {
 
     @Test
     // valid test case
-    public void StrandSortNullTest() {
+    public void strandSortNullTest() {
         Integer[] expectedArray = null;
         assertThrows(NullPointerException.class, () -> { new IntrospectiveSort().sort(expectedArray); });
     }
 
     @Test
     // valid test case
-    public void StrandSortNegativeTest() {
+    public void strandSortNegativeTest() {
         Integer[] expectedArray = {-1, -2, -3, -4, -5};
         Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
         assertArrayEquals(expectedArray, actualList);
@@ -47,7 +47,7 @@ public void StrandSortNegativeTest() {
 
     @Test
     // valid test case
-    public void StrandSortNegativeAndPositiveTest() {
+    public void strandSortNegativeAndPositiveTest() {
         Integer[] expectedArray = {-1, -2, -3, 4, 5};
         Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
         assertArrayEquals(expectedArray, actualList);
diff --git a/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java b/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java
index a718f450071f..83fbd1ece909 100644
--- a/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java
@@ -8,7 +8,7 @@ class SelectionSortTest {
 
     @Test
     // valid test case
-    void IntegerArrTest() {
+    void integerArrTest() {
         Integer[] arr = {4, 23, 6, 78, 1, 54, 231, 9, 12};
         SelectionSort selectionSort = new SelectionSort();
 
@@ -17,7 +17,7 @@ void IntegerArrTest() {
 
     @Test
     // valid test case
-    void StringArrTest() {
+    void stringArrTest() {
         String[] arr = {"c", "a", "e", "b", "d"};
         SelectionSort selectionSort = new SelectionSort();
 
diff --git a/src/test/java/com/thealgorithms/sorts/ShellSortTest.java b/src/test/java/com/thealgorithms/sorts/ShellSortTest.java
index cecc8d8bd581..73be91b397bd 100644
--- a/src/test/java/com/thealgorithms/sorts/ShellSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/ShellSortTest.java
@@ -9,7 +9,7 @@ public class ShellSortTest {
     private ShellSort shellSort = new ShellSort();
 
     @Test
-    public void ShellSortEmptyArray() {
+    public void shellSortEmptyArray() {
         Integer[] inputArray = {};
         Integer[] outputArray = shellSort.sort(inputArray);
         Integer[] expectedOutput = {};
@@ -17,7 +17,7 @@ public void ShellSortEmptyArray() {
     }
 
     @Test
-    public void ShellSortSingleIntegerArray() {
+    public void shellSortSingleIntegerArray() {
         Integer[] inputArray = {4};
         Integer[] outputArray = shellSort.sort(inputArray);
         Integer[] expectedOutput = {4};
@@ -25,7 +25,7 @@ public void ShellSortSingleIntegerArray() {
     }
 
     @Test
-    public void ShellSortSingleStringArray() {
+    public void shellSortSingleStringArray() {
         String[] inputArray = {"s"};
         String[] outputArray = shellSort.sort(inputArray);
         String[] expectedOutput = {"s"};
@@ -33,7 +33,7 @@ public void ShellSortSingleStringArray() {
     }
 
     @Test
-    public void ShellSortNonDuplicateIntegerArray() {
+    public void shellSortNonDuplicateIntegerArray() {
         Integer[] inputArray = {6, -1, 99, 27, -15, 23, -36};
         Integer[] outputArray = shellSort.sort(inputArray);
         Integer[] expectedOutput = {-36, -15, -1, 6, 23, 27, 99};
@@ -41,7 +41,7 @@ public void ShellSortNonDuplicateIntegerArray() {
     }
 
     @Test
-    public void ShellSortDuplicateIntegerArray() {
+    public void shellSortDuplicateIntegerArray() {
         Integer[] inputArray = {6, -1, 27, -15, 23, 27, -36, 23};
         Integer[] outputArray = shellSort.sort(inputArray);
         Integer[] expectedOutput = {-36, -15, -1, 6, 23, 23, 27, 27};
@@ -49,7 +49,7 @@ public void ShellSortDuplicateIntegerArray() {
     }
 
     @Test
-    public void ShellSortNonDuplicateStringArray() {
+    public void shellSortNonDuplicateStringArray() {
         String[] inputArray = {"s", "b", "k", "a", "d", "c", "h"};
         String[] outputArray = shellSort.sort(inputArray);
         String[] expectedOutput = {"a", "b", "c", "d", "h", "k", "s"};
@@ -57,7 +57,7 @@ public void ShellSortNonDuplicateStringArray() {
     }
 
     @Test
-    public void ShellSortDuplicateStringArray() {
+    public void shellSortDuplicateStringArray() {
         String[] inputArray = {"s", "b", "d", "a", "d", "c", "h", "b"};
         String[] outputArray = shellSort.sort(inputArray);
         String[] expectedOutput = {"a", "b", "b", "c", "d", "d", "h", "s"};
diff --git a/src/test/java/com/thealgorithms/sorts/StrandSortTest.java b/src/test/java/com/thealgorithms/sorts/StrandSortTest.java
index 4a0001a43647..91e85c81e5ec 100644
--- a/src/test/java/com/thealgorithms/sorts/StrandSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/StrandSortTest.java
@@ -10,7 +10,7 @@ class StrandSortTest {
 
     @Test
     // valid test case
-    public void StrandSortNonDuplicateTest() {
+    public void strandSortNonDuplicateTest() {
         int[] expectedArray = {1, 2, 3, 4, 5};
         LinkedList<Integer> actualList = StrandSort.strandSort(new LinkedList<Integer>(Arrays.asList(3, 1, 2, 4, 5)));
         int[] actualArray = new int[actualList.size()];
@@ -22,7 +22,7 @@ public void StrandSortNonDuplicateTest() {
 
     @Test
     // valid test case
-    public void StrandSortDuplicateTest() {
+    public void strandSortDuplicateTest() {
         int[] expectedArray = {2, 2, 2, 5, 7};
         LinkedList<Integer> actualList = StrandSort.strandSort(new LinkedList<Integer>(Arrays.asList(7, 2, 2, 2, 5)));
         int[] actualArray = new int[actualList.size()];
diff --git a/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java b/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java
index 449c8c11ba78..c5d57d63cf38 100644
--- a/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java
@@ -8,7 +8,7 @@
 public class WiggleSortTest {
 
     @Test
-    void WiggleTestNumbersEven() {
+    void wiggleTestNumbersEven() {
         WiggleSort wiggleSort = new WiggleSort();
         Integer[] values = {1, 2, 3, 4};
         Integer[] result = {1, 4, 2, 3};
@@ -17,7 +17,7 @@ void WiggleTestNumbersEven() {
     }
 
     @Test
-    void WiggleTestNumbersOdd() {
+    void wiggleTestNumbersOdd() {
         WiggleSort wiggleSort = new WiggleSort();
         Integer[] values = {1, 2, 3, 4, 5};
         Integer[] result = {3, 5, 1, 4, 2};
@@ -26,7 +26,7 @@ void WiggleTestNumbersOdd() {
     }
 
     @Test
-    void WiggleTestNumbersOddDuplicates() {
+    void wiggleTestNumbersOddDuplicates() {
         WiggleSort wiggleSort = new WiggleSort();
         Integer[] values = {7, 2, 2, 2, 5};
         Integer[] result = {2, 7, 2, 5, 2};
@@ -35,7 +35,7 @@ void WiggleTestNumbersOddDuplicates() {
     }
 
     @Test
-    void WiggleTestNumbersOddMultipleDuplicates() {
+    void wiggleTestNumbersOddMultipleDuplicates() {
         WiggleSort wiggleSort = new WiggleSort();
         Integer[] values = {1, 1, 2, 2, 5};
         Integer[] result = {2, 5, 1, 2, 1};
@@ -44,7 +44,7 @@ void WiggleTestNumbersOddMultipleDuplicates() {
     }
 
     @Test
-    void WiggleTestNumbersEvenMultipleDuplicates() {
+    void wiggleTestNumbersEvenMultipleDuplicates() {
         WiggleSort wiggleSort = new WiggleSort();
         Integer[] values = {1, 1, 2, 2, 2, 5};
         Integer[] result = {2, 5, 1, 2, 1, 2};
@@ -54,7 +54,7 @@ void WiggleTestNumbersEvenMultipleDuplicates() {
     }
 
     @Test
-    void WiggleTestNumbersEvenDuplicates() {
+    void wiggleTestNumbersEvenDuplicates() {
         WiggleSort wiggleSort = new WiggleSort();
         Integer[] values = {1, 2, 4, 4};
         Integer[] result = {1, 4, 2, 4};
@@ -63,7 +63,7 @@ void WiggleTestNumbersEvenDuplicates() {
     }
 
     @Test
-    void WiggleTestStrings() {
+    void wiggleTestStrings() {
         WiggleSort wiggleSort = new WiggleSort();
         String[] values = {"a", "b", "d", "c"};
         String[] result = {"a", "d", "b", "c"};
diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
index 137ec7a949ab..e73f7afce8eb 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
@@ -7,7 +7,7 @@
 public class ReverseStringTest {
 
     @Test
-    public void ReverseStringTest() {
+    public void testReverseString() {
         String input1 = "Hello World";
         String input2 = "helloworld";
         String input3 = "123456789";

From 70c1d97ab1ec41e3412f6b3c45fd1cb4e1878142 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 27 May 2024 23:07:20 +0200
Subject: [PATCH 0173/1338] style: include `SPP_TOSTRING_ON_STRING` (#5183)

---
 spotbugs-exclude.xml                             | 3 ---
 src/main/java/com/thealgorithms/ciphers/DES.java | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index ffccae635f3b..32a1292675ae 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -261,9 +261,6 @@
     <Match>
         <Bug pattern="SLS_SUSPICIOUS_LOOP_SEARCH" />
     </Match>
-    <Match>
-        <Bug pattern="SPP_TOSTRING_ON_STRING" />
-    </Match>
     <!-- find-sec-bugs -->
     <Match>
         <Bug pattern="PREDICTABLE_RANDOM" />
diff --git a/src/main/java/com/thealgorithms/ciphers/DES.java b/src/main/java/com/thealgorithms/ciphers/DES.java
index 5d27ca67015b..4f92c18eb3be 100644
--- a/src/main/java/com/thealgorithms/ciphers/DES.java
+++ b/src/main/java/com/thealgorithms/ciphers/DES.java
@@ -238,7 +238,7 @@ public String decrypt(String message) {
         }
         for (i = 0; i < l; i += 64) {
             String block = message.substring(i, i + 64);
-            String result = decryptBlock(block.toString(), subKeys);
+            String result = decryptBlock(block, subKeys);
             byte[] res = new byte[8];
             for (j = 0; j < 64; j += 8) {
                 res[j / 8] = (byte) Integer.parseInt(result.substring(j, j + 8), 2);

From 92887a10c2a1d7b06cd3c6c273a00dd2ea42ad1a Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 28 May 2024 08:47:51 +0200
Subject: [PATCH 0174/1338] style: include `NAB_NEEDLESS_BOXING_PARSE` (#5184)

---
 spotbugs-exclude.xml                                     | 3 ---
 src/main/java/com/thealgorithms/maths/HarshadNumber.java | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 32a1292675ae..99a24bbff9d5 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -225,9 +225,6 @@
     <Match>
         <Bug pattern="ENMI_EQUALS_ON_ENUM" />
     </Match>
-    <Match>
-        <Bug pattern="NAB_NEEDLESS_BOXING_PARSE" />
-    </Match>
     <Match>
         <Bug pattern="IMC_IMMATURE_CLASS_VAR_NAME" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/maths/HarshadNumber.java b/src/main/java/com/thealgorithms/maths/HarshadNumber.java
index e063c860ca6a..0b1ba1285c4d 100644
--- a/src/main/java/com/thealgorithms/maths/HarshadNumber.java
+++ b/src/main/java/com/thealgorithms/maths/HarshadNumber.java
@@ -34,7 +34,7 @@ public static boolean isHarshad(long n) {
      *         {@code false}
      */
     public static boolean isHarshad(String s) {
-        long n = Long.valueOf(s);
+        final Long n = Long.valueOf(s);
         if (n <= 0) return false;
 
         int sumOfDigits = 0;

From 33a34841bbc6001b0ad069b3dc8fb317560625bf Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 28 May 2024 09:08:45 +0200
Subject: [PATCH 0175/1338] Chore(deps-dev): bump org.assertj:assertj-core from
 3.25.3 to 3.26.0 (#5187)

Bumps [org.assertj:assertj-core](https://github.com/assertj/assertj) from 3.25.3 to 3.26.0.
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](https://github.com/assertj/assertj/compare/assertj-build-3.25.3...assertj-build-3.26.0)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 134732953c03..39e9c5a9e8ae 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.25.3</assertj.version>
+        <assertj.version>3.26.0</assertj.version>
     </properties>
 
     <dependencyManagement>

From 23ed1196c02fb324c1423e19b00f6e90875693cd Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 28 May 2024 09:16:09 +0200
Subject: [PATCH 0176/1338] Chore(deps): bump gitpod/workspace-java-21 from
 2024-05-15-13-36-34 to 2024-05-27-17-11-15 (#5185)

Chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2024-05-15-13-36-34 to 2024-05-27-17-11-15.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 0bba1827bc86..1c1c0852d21c 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-05-15-13-36-34
+FROM gitpod/workspace-java-21:2024-05-27-17-11-15
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 81cb09b1f838e15ac503c2547672fa205de6c409 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 28 May 2024 09:22:21 +0200
Subject: [PATCH 0177/1338] Chore(deps): bump com.puppycrawl.tools:checkstyle
 from 10.16.0 to 10.17.0 (#5186)

Chore(deps): bump com.puppycrawl.tools:checkstyle

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.16.0 to 10.17.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.16.0...checkstyle-10.17.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 39e9c5a9e8ae..b8fb946eeb5a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -118,7 +118,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.16.0</version>
+                    <version>10.17.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 25d711c5d8c981eebbc7c48cb171dbd1dac40d7e Mon Sep 17 00:00:00 2001
From: "S. Utkarsh" <69796213+cpu-pixel@users.noreply.github.com>
Date: Tue, 28 May 2024 23:59:28 +0530
Subject: [PATCH 0178/1338] style: enable `LocalVariableName` in CheckStyle
 (#5191)

* style: enable LocalVariableName in checkstyle

* Removed minor bug

* Resolved Method Name Bug

* Changed names according to suggestions
---
 checkstyle.xml                                |   2 +-
 .../thealgorithms/ciphers/AffineCipher.java   |   6 +-
 .../java/com/thealgorithms/ciphers/DES.java   |  28 ++--
 .../com/thealgorithms/ciphers/HillCipher.java |  12 +-
 .../conversions/HexaDecimalToDecimal.java     |  12 +-
 .../graphs/BipartiteGrapfDFS.java             |  22 +--
 .../graphs/DIJSKSTRAS_ALGORITHM.java          |  20 +--
 .../datastructures/graphs/PrimMST.java        |   6 +-
 .../datastructures/hashmap/hashing/Main.java  |  10 +-
 .../hashmap/hashing/MainCuckooHashing.java    |  12 +-
 .../lists/CursorLinkedList.java               |  34 ++---
 .../datastructures/lists/ReverseKGroup.java   |  10 +-
 .../datastructures/stacks/NodeStack.java      |  20 +--
 .../datastructures/trees/AVLSimple.java       |   8 +-
 .../trees/PrintTopViewofTree.java             |  12 +-
 .../datastructures/trees/SegmentTree.java     |   4 +-
 .../StrassenMatrixMultiplication.java         | 130 +++++++++---------
 .../BruteForceKnapsack.java                   |   4 +-
 .../dynamicprogramming/CoinChange.java        |   6 +-
 .../dynamicprogramming/KadaneAlgorithm.java   |   8 +-
 .../LongestIncreasingSubsequence.java         |   8 +-
 .../PalindromicPartitioning.java              |  16 +--
 .../ShortestCommonSupersequenceLength.java    |  42 +++---
 .../thealgorithms/maths/CrossCorrelation.java |   6 +-
 .../java/com/thealgorithms/maths/FFT.java     |  46 +++----
 .../com/thealgorithms/maths/FFTBluestein.java |  24 ++--
 .../com/thealgorithms/maths/KeithNumber.java  |  14 +-
 .../com/thealgorithms/maths/LongDivision.java |  42 +++---
 .../com/thealgorithms/maths/MagicSquare.java  |  24 ++--
 .../maths/SimpsonIntegration.java             |  16 +--
 .../maths/VectorCrossProduct.java             |  10 +-
 .../others/InsertDeleteInArray.java           |  10 +-
 .../com/thealgorithms/others/PageRank.java    |  44 +++---
 .../others/ReturnSubsequence.java             |  14 +-
 .../thealgorithms/others/RootPrecision.java   |  18 +--
 .../java/com/thealgorithms/others/Sudoku.java |  14 +-
 .../com/thealgorithms/searches/KMPSearch.java |  20 +--
 .../searches/OrderAgnosticBinarySearch.java   |   4 +-
 .../java/com/thealgorithms/sorts/DNFSort.java |  14 +-
 .../com/thealgorithms/sorts/SwapSort.java     |   4 +-
 .../com/thealgorithms/strings/MyAtoi.java     |   4 +-
 .../com/thealgorithms/strings/WordLadder.java |  22 +--
 .../strings/zigZagPattern/zigZagPattern.java  |  16 +--
 .../StrassenMatrixMultiplicationTest.java     |  21 +--
 .../OptimalJobSchedulingTest.java             |  18 +--
 45 files changed, 419 insertions(+), 418 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index e5c8b7ed7a38..6357bcb4ddbd 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -110,7 +110,7 @@
     <!-- See https://checkstyle.org/checks/naming/index.html -->
     <module name="ConstantName"/>
     <module name="LocalFinalVariableName"/>
-    <!-- TODO <module name="LocalVariableName"/> -->
+    <module name="LocalVariableName"/>
     <!-- TODO <module name="MemberName"/> -->
     <module name="MethodName"/>
     <module name="PackageName"/>
diff --git a/src/main/java/com/thealgorithms/ciphers/AffineCipher.java b/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
index 6e819f56041c..bcf3a5b0167b 100644
--- a/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
@@ -27,7 +27,7 @@ static String encryptMessage(char[] msg) {
 
     static String decryptCipher(String cipher) {
         String msg = "";
-        int a_inv = 0;
+        int aInv = 0;
         int flag = 0;
 
         // Find a^-1 (the multiplicative inverse of a
@@ -38,7 +38,7 @@ static String decryptCipher(String cipher) {
             // Check if (a*i)%26 == 1,
             // then i will be the multiplicative inverse of a
             if (flag == 1) {
-                a_inv = i;
+                aInv = i;
             }
         }
         for (int i = 0; i < cipher.length(); i++) {
@@ -46,7 +46,7 @@ static String decryptCipher(String cipher) {
             {here x is cipher[i] and m is 26} and added 'A'
             to bring it in range of ASCII alphabet[ 65-90 | A-Z ] */
             if (cipher.charAt(i) != ' ') {
-                msg = msg + (char) (((a_inv * ((cipher.charAt(i) + 'A' - b)) % 26)) + 'A');
+                msg = msg + (char) (((aInv * ((cipher.charAt(i) + 'A' - b)) % 26)) + 'A');
             } else { // else simply append space character
                 msg += cipher.charAt(i);
             }
diff --git a/src/main/java/com/thealgorithms/ciphers/DES.java b/src/main/java/com/thealgorithms/ciphers/DES.java
index 4f92c18eb3be..7f3eed70f3c2 100644
--- a/src/main/java/com/thealgorithms/ciphers/DES.java
+++ b/src/main/java/com/thealgorithms/ciphers/DES.java
@@ -81,16 +81,16 @@ private String[] getSubkeys(String originalKey) {
         }
         String[] subKeys = new String[16];
         String initialPermutedKey = permutedKey.toString();
-        String C0 = initialPermutedKey.substring(0, 28);
-        String D0 = initialPermutedKey.substring(28);
+        String c0 = initialPermutedKey.substring(0, 28);
+        String d0 = initialPermutedKey.substring(28);
 
         // We will now operate on the left and right halves of the permutedKey
         for (i = 0; i < 16; i++) {
-            String Cn = C0.substring(KEY_SHIFTS[i]) + C0.substring(0, KEY_SHIFTS[i]);
-            String Dn = D0.substring(KEY_SHIFTS[i]) + D0.substring(0, KEY_SHIFTS[i]);
-            subKeys[i] = Cn + Dn;
-            C0 = Cn; // Re-assign the values to create running permutation
-            D0 = Dn;
+            String cN = c0.substring(KEY_SHIFTS[i]) + c0.substring(0, KEY_SHIFTS[i]);
+            String dN = d0.substring(KEY_SHIFTS[i]) + d0.substring(0, KEY_SHIFTS[i]);
+            subKeys[i] = cN + dN;
+            c0 = cN; // Re-assign the values to create running permutation
+            d0 = dN;
         }
 
         // Let us shrink the keys to 48 bits (well, characters here) using pc2
@@ -169,18 +169,18 @@ private String encryptBlock(String message, String[] keys) {
         for (i = 0; i < 64; i++) {
             permutedMessage.append(message.charAt(IP[i] - 1));
         }
-        String L0 = permutedMessage.substring(0, 32);
-        String R0 = permutedMessage.substring(32);
+        String e0 = permutedMessage.substring(0, 32);
+        String f0 = permutedMessage.substring(32);
 
         // Iterate 16 times
         for (i = 0; i < 16; i++) {
-            String Ln = R0; // Previous Right block
-            String Rn = xOR(L0, feistel(R0, keys[i]));
-            L0 = Ln;
-            R0 = Rn;
+            String eN = f0; // Previous Right block
+            String fN = xOR(e0, feistel(f0, keys[i]));
+            e0 = eN;
+            f0 = fN;
         }
 
-        String combinedBlock = R0 + L0; // Reverse the 16th block
+        String combinedBlock = f0 + e0; // Reverse the 16th block
         permutedMessage.setLength(0);
         for (i = 0; i < 64; i++) {
             permutedMessage.append(combinedBlock.charAt(IP_INVERSE[i] - 1));
diff --git a/src/main/java/com/thealgorithms/ciphers/HillCipher.java b/src/main/java/com/thealgorithms/ciphers/HillCipher.java
index 0ef7bc82f00e..780009c2f1d6 100644
--- a/src/main/java/com/thealgorithms/ciphers/HillCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/HillCipher.java
@@ -35,7 +35,7 @@ static void encrypt(String message) {
         validateDeterminant(keyMatrix, matrixSize);
 
         int[][] messageVector = new int[matrixSize][1];
-        String CipherText = "";
+        String cipherText = "";
         int[][] cipherMatrix = new int[matrixSize][1];
         int j = 0;
         while (j < message.length()) {
@@ -60,10 +60,10 @@ static void encrypt(String message) {
                 cipherMatrix[i][0] = cipherMatrix[i][0] % 26;
             }
             for (i = 0; i < matrixSize; i++) {
-                CipherText += (char) (cipherMatrix[i][0] + 65);
+                cipherText += (char) (cipherMatrix[i][0] + 65);
             }
         }
-        System.out.println("Ciphertext: " + CipherText);
+        System.out.println("Ciphertext: " + cipherText);
     }
 
     // Following function decrypts a message
@@ -84,7 +84,7 @@ static void decrypt(String message) {
 
         // solving for the required plaintext message
         int[][] messageVector = new int[n][1];
-        String PlainText = "";
+        String plainText = "";
         int[][] plainMatrix = new int[n][1];
         int j = 0;
         while (j < message.length()) {
@@ -109,10 +109,10 @@ static void decrypt(String message) {
                 plainMatrix[i][0] = plainMatrix[i][0] % 26;
             }
             for (i = 0; i < n; i++) {
-                PlainText += (char) (plainMatrix[i][0] + 65);
+                plainText += (char) (plainMatrix[i][0] + 65);
             }
         }
-        System.out.println("Plaintext: " + PlainText);
+        System.out.println("Plaintext: " + plainText);
     }
 
     // Determinant calculator
diff --git a/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java b/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java
index e8a44cb827d5..003781da9d5e 100644
--- a/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java
@@ -20,20 +20,20 @@ public static int getHexaToDec(String hex) {
 
     // Main method gets the hexadecimal input from user and converts it into Decimal output.
     public static void main(String[] args) {
-        String hexa_Input;
-        int dec_output;
+        String hexaInput;
+        int decOutput;
         Scanner scan = new Scanner(System.in);
 
         System.out.print("Enter Hexadecimal Number : ");
-        hexa_Input = scan.nextLine();
+        hexaInput = scan.nextLine();
 
         // convert hexadecimal to decimal
-        dec_output = getHexaToDec(hexa_Input);
+        decOutput = getHexaToDec(hexaInput);
         /*
     Pass the string to the getHexaToDec function
-    and it returns the decimal form in the variable dec_output.
+    and it returns the decimal form in the variable decOutput.
          */
-        System.out.println("Number in Decimal: " + dec_output);
+        System.out.println("Number in Decimal: " + decOutput);
         scan.close();
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java b/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
index 6b41b658d5e2..1e82ca0cd421 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
@@ -54,23 +54,23 @@ public static void main(String[] args) throws IOException {
         BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
         int t = Integer.parseInt(read.readLine().trim());
         while (t-- > 0) {
-            String[] S = read.readLine().trim().split(" ");
-            int V = Integer.parseInt(S[0]);
-            int E = Integer.parseInt(S[1]);
+            String[] str1 = read.readLine().trim().split(" ");
+            int numVertices = Integer.parseInt(str1[0]);
+            int numEdges = Integer.parseInt(str1[1]);
 
             ArrayList<ArrayList<Integer>> adj = new ArrayList<>();
-            for (int i = 0; i < V; i++) {
+            for (int i = 0; i < numVertices; i++) {
                 adj.add(new ArrayList<>());
             }
-            for (int i = 0; i < E; i++) {
-                String[] s = read.readLine().trim().split(" ");
-                int u = Integer.parseInt(s[0]);
-                int v = Integer.parseInt(s[1]);
-                adj.get(u).add(v);
-                adj.get(v).add(u);
+            for (int i = 0; i < numEdges; i++) {
+                String[] str2 = read.readLine().trim().split(" ");
+                int vertexU = Integer.parseInt(str2[0]);
+                int vertexV = Integer.parseInt(str2[1]);
+                adj.get(vertexU).add(vertexV);
+                adj.get(vertexV).add(vertexU);
             }
 
-            boolean ans = isBipartite(V, adj);
+            boolean ans = isBipartite(numVertices, adj);
             if (ans) {
                 System.out.println("YES");
             } else {
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java b/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
index 865c276f0e20..8503aa48ec37 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
@@ -8,18 +8,18 @@ class dijkstras {
 
     int k = 9;
 
-    int minDist(int[] dist, Boolean[] Set) {
+    int minDist(int[] dist, Boolean[] set) {
         int min = Integer.MAX_VALUE;
-        int min_index = -1;
+        int minIndex = -1;
 
         for (int r = 0; r < k; r++) {
-            if (!Set[r] && dist[r] <= min) {
+            if (!set[r] && dist[r] <= min) {
                 min = dist[r];
-                min_index = r;
+                minIndex = r;
             }
         }
 
-        return min_index;
+        return minIndex;
     }
 
     void print(int[] dist) {
@@ -31,22 +31,22 @@ void print(int[] dist) {
 
     void dijkstra(int[][] graph, int src) {
         int[] dist = new int[k];
-        Boolean[] Set = new Boolean[k];
+        Boolean[] set = new Boolean[k];
 
         for (int i = 0; i < k; i++) {
             dist[i] = Integer.MAX_VALUE;
-            Set[i] = Boolean.FALSE;
+            set[i] = Boolean.FALSE;
         }
 
         dist[src] = 0;
 
         for (int c = 0; c < k - 1; c++) {
-            int u = minDist(dist, Set);
+            int u = minDist(dist, set);
 
-            Set[u] = Boolean.TRUE;
+            set[u] = Boolean.TRUE;
 
             for (int v = 0; v < k; v++) {
-                if (!Set[v] && graph[u][v] != 0 && dist[u] != Integer.MAX_VALUE && dist[u] + graph[u][v] < dist[v]) {
+                if (!set[v] && graph[u][v] != 0 && dist[u] != Integer.MAX_VALUE && dist[u] + graph[u][v] < dist[v]) {
                     dist[v] = dist[u] + graph[u][v];
                 }
             }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java b/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
index 0d9eb87aedc0..7e11862786f6 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
@@ -15,16 +15,16 @@ class PrimMST {
     int minKey(int[] key, Boolean[] mstSet) {
         // Initialize min value
         int min = Integer.MAX_VALUE;
-        int min_index = -1;
+        int minIndex = -1;
 
         for (int v = 0; v < V; v++) {
             if (!mstSet[v] && key[v] < min) {
                 min = key[v];
-                min_index = v;
+                minIndex = v;
             }
         }
 
-        return min_index;
+        return minIndex;
     }
 
     // A utility function to print the constructed MST stored in
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
index f1dbb332057b..082fd4b5ab2a 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
@@ -11,7 +11,7 @@ public static void main(String[] args) {
         int key;
 
         HashMap h = new HashMap(7);
-        Scanner In = new Scanner(System.in);
+        Scanner scan = new Scanner(System.in);
 
         while (true) {
             System.out.println("Enter your Choice :");
@@ -20,18 +20,18 @@ public static void main(String[] args) {
             System.out.println("3. Print Table");
             System.out.println("4. Exit");
 
-            choice = In.nextInt();
+            choice = scan.nextInt();
 
             switch (choice) {
             case 1: {
                 System.out.println("Enter the Key: ");
-                key = In.nextInt();
+                key = scan.nextInt();
                 h.insertHash(key);
                 break;
             }
             case 2: {
                 System.out.println("Enter the Key delete:  ");
-                key = In.nextInt();
+                key = scan.nextInt();
                 h.deleteHash(key);
                 break;
             }
@@ -41,7 +41,7 @@ public static void main(String[] args) {
                 break;
             }
             case 4: {
-                In.close();
+                scan.close();
                 return;
             }
             default: {
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
index 772e164239e0..5a4a56e9b37d 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
@@ -11,7 +11,7 @@ public static void main(String[] args) {
         int key;
 
         HashMapCuckooHashing h = new HashMapCuckooHashing(7);
-        Scanner In = new Scanner(System.in);
+        Scanner scan = new Scanner(System.in);
 
         while (true) {
             System.out.println("_________________________");
@@ -24,18 +24,18 @@ public static void main(String[] args) {
             System.out.println("6. Check load factor");
             System.out.println("7. Rehash Current Table");
 
-            choice = In.nextInt();
+            choice = scan.nextInt();
 
             switch (choice) {
             case 1: {
                 System.out.println("Enter the Key: ");
-                key = In.nextInt();
+                key = scan.nextInt();
                 h.insertKey2HashTable(key);
                 break;
             }
             case 2: {
                 System.out.println("Enter the Key delete:  ");
-                key = In.nextInt();
+                key = scan.nextInt();
                 h.deleteKeyFromHashTable(key);
                 break;
             }
@@ -45,12 +45,12 @@ public static void main(String[] args) {
                 break;
             }
             case 4: {
-                In.close();
+                scan.close();
                 return;
             }
             case 5: {
                 System.out.println("Enter the Key to find and print:  ");
-                key = In.nextInt();
+                key = scan.nextInt();
                 System.out.println("Key: " + key + " is at index: " + h.findKeyInTable(key) + "\n");
                 break;
             }
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
index 22399bd6a459..b4fa9c51d4dc 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
@@ -108,25 +108,25 @@ public void remove(T element) {
         Objects.requireNonNull(element);
 
         // case element is in the head
-        T temp_element = cursorSpace[head].element;
-        int temp_next = cursorSpace[head].next;
-        if (temp_element.equals(element)) {
+        T tempElement = cursorSpace[head].element;
+        int tempNext = cursorSpace[head].next;
+        if (tempElement.equals(element)) {
             free(head);
-            head = temp_next;
+            head = tempNext;
         } else { // otherwise cases
-            int prev_index = head;
-            int current_index = cursorSpace[prev_index].next;
-
-            while (current_index != -1) {
-                T current_element = cursorSpace[current_index].element;
-                if (current_element.equals(element)) {
-                    cursorSpace[prev_index].next = cursorSpace[current_index].next;
-                    free(current_index);
+            int prevIndex = head;
+            int currentIndex = cursorSpace[prevIndex].next;
+
+            while (currentIndex != -1) {
+                T currentElement = cursorSpace[currentIndex].element;
+                if (currentElement.equals(element)) {
+                    cursorSpace[prevIndex].next = cursorSpace[currentIndex].next;
+                    free(currentIndex);
                     break;
                 }
 
-                prev_index = current_index;
-                current_index = cursorSpace[prev_index].next;
+                prevIndex = currentIndex;
+                currentIndex = cursorSpace[prevIndex].next;
             }
         }
 
@@ -134,11 +134,11 @@ public void remove(T element) {
     }
 
     private void free(int index) {
-        Node<T> os_node = cursorSpace[os];
-        int os_next = os_node.next;
+        Node<T> osNode = cursorSpace[os];
+        int osNext = osNode.next;
         cursorSpace[os].next = index;
         cursorSpace[index].element = null;
-        cursorSpace[index].next = os_next;
+        cursorSpace[index].next = osNext;
     }
 
     public void append(T element) {
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java b/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
index bd599e2ab91f..3c4b9331266c 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
@@ -23,17 +23,17 @@ public Node reverse(Node head, int count, int k) {
         Node prev = null;
         int count1 = 0;
         Node curr = head;
-        Node Next = null;
+        Node next = null;
         while (curr != null && count1 < k) {
-            Next = curr.next;
+            next = curr.next;
             curr.next = prev;
             prev = curr;
-            curr = Next;
+            curr = next;
             count1++;
         }
 
-        if (Next != null) {
-            head.next = reverse(Next, count - k, k);
+        if (next != null) {
+            head.next = reverse(next, count - k, k);
         }
         return prev;
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java b/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java
index 900d697f36f7..7c4f334cd617 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java
@@ -11,20 +11,20 @@ public class NodeStack<Item> {
      * Entry point for the program.
      */
     public static void main(String[] args) {
-        NodeStack<Integer> Stack = new NodeStack<Integer>();
+        NodeStack<Integer> stack = new NodeStack<Integer>();
 
-        Stack.push(3);
-        Stack.push(4);
-        Stack.push(5);
+        stack.push(3);
+        stack.push(4);
+        stack.push(5);
         System.out.println("Testing :");
-        Stack.print(); // prints : 5 4 3
+        stack.print(); // prints : 5 4 3
 
-        Integer x = Stack.pop(); // x = 5
-        Stack.push(1);
-        Stack.push(8);
-        Integer y = Stack.peek(); // y = 8
+        Integer x = stack.pop(); // x = 5
+        stack.push(1);
+        stack.push(8);
+        Integer y = stack.peek(); // y = 8
         System.out.println("Testing :");
-        Stack.print(); // prints : 8 1 4 3
+        stack.print(); // prints : 8 1 4 3
 
         System.out.println("Testing :");
         System.out.println("x : " + x);
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java b/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java
index 1032daa240f8..052da616fe8e 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java
@@ -112,10 +112,10 @@ private int bf(Node node) {
 
     private Node rightRotate(Node c) {
         Node b = c.left;
-        Node T3 = b.right;
+        Node t3 = b.right;
 
         b.right = c;
-        c.left = T3;
+        c.left = t3;
         c.height = Math.max(height(c.left), height(c.right)) + 1;
         b.height = Math.max(height(b.left), height(b.right)) + 1;
         return b;
@@ -123,10 +123,10 @@ private Node rightRotate(Node c) {
 
     private Node leftRotate(Node c) {
         Node b = c.right;
-        Node T3 = b.left;
+        Node t3 = b.left;
 
         b.left = c;
-        c.right = T3;
+        c.right = t3;
         c.height = Math.max(height(c.left), height(c.right)) + 1;
         b.height = Math.max(height(b.left), height(b.right)) + 1;
         return b;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java b/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
index 88343db3d0e8..3ef664f3fa7d 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java
@@ -60,13 +60,13 @@ public void printTopView() {
         HashSet<Integer> set = new HashSet<>();
 
         // Create a queue and add root to it
-        Queue<QItem> Q = new LinkedList<QItem>();
-        Q.add(new QItem(root, 0)); // Horizontal distance of root is 0
+        Queue<QItem> queue = new LinkedList<QItem>();
+        queue.add(new QItem(root, 0)); // Horizontal distance of root is 0
 
         // Standard BFS or level order traversal loop
-        while (!Q.isEmpty()) {
+        while (!queue.isEmpty()) {
             // Remove the front item and get its details
-            QItem qi = Q.remove();
+            QItem qi = queue.remove();
             int hd = qi.hd;
             TreeNode n = qi.node;
 
@@ -79,10 +79,10 @@ public void printTopView() {
 
             // Enqueue left and right children of current node
             if (n.left != null) {
-                Q.add(new QItem(n.left, hd - 1));
+                queue.add(new QItem(n.left, hd - 1));
             }
             if (n.right != null) {
-                Q.add(new QItem(n.right, hd + 1));
+                queue.add(new QItem(n.right, hd + 1));
             }
         }
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
index 55efe30adcd8..a6954b24cf3a 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
@@ -10,9 +10,9 @@ public class SegmentTree {
     public SegmentTree(int n, int[] arr) {
         this.n = n;
         int x = (int) (Math.ceil(Math.log(n) / Math.log(2)));
-        int seg_size = 2 * (int) Math.pow(2, x) - 1;
+        int segSize = 2 * (int) Math.pow(2, x) - 1;
 
-        this.seg_t = new int[seg_size];
+        this.seg_t = new int[segSize];
         this.arr = arr;
         this.n = n;
         constructTree(arr, 0, n - 1, 0);
diff --git a/src/main/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplication.java b/src/main/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplication.java
index 4c25066a3553..86a6f3e11483 100644
--- a/src/main/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplication.java
+++ b/src/main/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplication.java
@@ -18,124 +18,124 @@
 public class StrassenMatrixMultiplication {
 
     // Function to multiply matrices
-    public int[][] multiply(int[][] A, int[][] B) {
-        int n = A.length;
+    public int[][] multiply(int[][] a, int[][] b) {
+        int n = a.length;
 
-        int[][] R = new int[n][n];
+        int[][] mat = new int[n][n];
 
         if (n == 1) {
-            R[0][0] = A[0][0] * B[0][0];
+            mat[0][0] = a[0][0] * b[0][0];
         } else {
             // Dividing Matrix into parts
             // by storing sub-parts to variables
-            int[][] A11 = new int[n / 2][n / 2];
-            int[][] A12 = new int[n / 2][n / 2];
-            int[][] A21 = new int[n / 2][n / 2];
-            int[][] A22 = new int[n / 2][n / 2];
-            int[][] B11 = new int[n / 2][n / 2];
-            int[][] B12 = new int[n / 2][n / 2];
-            int[][] B21 = new int[n / 2][n / 2];
-            int[][] B22 = new int[n / 2][n / 2];
+            int[][] a11 = new int[n / 2][n / 2];
+            int[][] a12 = new int[n / 2][n / 2];
+            int[][] a21 = new int[n / 2][n / 2];
+            int[][] a22 = new int[n / 2][n / 2];
+            int[][] b11 = new int[n / 2][n / 2];
+            int[][] b12 = new int[n / 2][n / 2];
+            int[][] b21 = new int[n / 2][n / 2];
+            int[][] b22 = new int[n / 2][n / 2];
 
             // Dividing matrix A into 4 parts
-            split(A, A11, 0, 0);
-            split(A, A12, 0, n / 2);
-            split(A, A21, n / 2, 0);
-            split(A, A22, n / 2, n / 2);
+            split(a, a11, 0, 0);
+            split(a, a12, 0, n / 2);
+            split(a, a21, n / 2, 0);
+            split(a, a22, n / 2, n / 2);
 
             // Dividing matrix B into 4 parts
-            split(B, B11, 0, 0);
-            split(B, B12, 0, n / 2);
-            split(B, B21, n / 2, 0);
-            split(B, B22, n / 2, n / 2);
+            split(b, b11, 0, 0);
+            split(b, b12, 0, n / 2);
+            split(b, b21, n / 2, 0);
+            split(b, b22, n / 2, n / 2);
 
             // Using Formulas as described in algorithm
-            // M1:=(A1+A3)×(B1+B2)
-            int[][] M1 = multiply(add(A11, A22), add(B11, B22));
+            // m1:=(A1+A3)×(B1+B2)
+            int[][] m1 = multiply(add(a11, a22), add(b11, b22));
 
-            // M2:=(A2+A4)×(B3+B4)
-            int[][] M2 = multiply(add(A21, A22), B11);
+            // m2:=(A2+A4)×(B3+B4)
+            int[][] m2 = multiply(add(a21, a22), b11);
 
-            // M3:=(A1−A4)×(B1+A4)
-            int[][] M3 = multiply(A11, sub(B12, B22));
+            // m3:=(A1−A4)×(B1+A4)
+            int[][] m3 = multiply(a11, sub(b12, b22));
 
-            // M4:=A1×(B2−B4)
-            int[][] M4 = multiply(A22, sub(B21, B11));
+            // m4:=A1×(B2−B4)
+            int[][] m4 = multiply(a22, sub(b21, b11));
 
-            // M5:=(A3+A4)×(B1)
-            int[][] M5 = multiply(add(A11, A12), B22);
+            // m5:=(A3+A4)×(B1)
+            int[][] m5 = multiply(add(a11, a12), b22);
 
-            // M6:=(A1+A2)×(B4)
-            int[][] M6 = multiply(sub(A21, A11), add(B11, B12));
+            // m6:=(A1+A2)×(B4)
+            int[][] m6 = multiply(sub(a21, a11), add(b11, b12));
 
-            // M7:=A4×(B3−B1)
-            int[][] M7 = multiply(sub(A12, A22), add(B21, B22));
+            // m7:=A4×(B3−B1)
+            int[][] m7 = multiply(sub(a12, a22), add(b21, b22));
 
-            // P:=M2+M3−M6−M7
-            int[][] C11 = add(sub(add(M1, M4), M5), M7);
+            // P:=m2+m3−m6−m7
+            int[][] c11 = add(sub(add(m1, m4), m5), m7);
 
-            // Q:=M4+M6
-            int[][] C12 = add(M3, M5);
+            // Q:=m4+m6
+            int[][] c12 = add(m3, m5);
 
-            // R:=M5+M7
-            int[][] C21 = add(M2, M4);
+            // mat:=m5+m7
+            int[][] c21 = add(m2, m4);
 
-            // S:=M1−M3−M4−M5
-            int[][] C22 = add(sub(add(M1, M3), M2), M6);
+            // S:=m1−m3−m4−m5
+            int[][] c22 = add(sub(add(m1, m3), m2), m6);
 
-            join(C11, R, 0, 0);
-            join(C12, R, 0, n / 2);
-            join(C21, R, n / 2, 0);
-            join(C22, R, n / 2, n / 2);
+            join(c11, mat, 0, 0);
+            join(c12, mat, 0, n / 2);
+            join(c21, mat, n / 2, 0);
+            join(c22, mat, n / 2, n / 2);
         }
 
-        return R;
+        return mat;
     }
 
     // Function to subtract two matrices
-    public int[][] sub(int[][] A, int[][] B) {
-        int n = A.length;
+    public int[][] sub(int[][] a, int[][] b) {
+        int n = a.length;
 
-        int[][] C = new int[n][n];
+        int[][] c = new int[n][n];
 
         for (int i = 0; i < n; i++) {
             for (int j = 0; j < n; j++) {
-                C[i][j] = A[i][j] - B[i][j];
+                c[i][j] = a[i][j] - b[i][j];
             }
         }
 
-        return C;
+        return c;
     }
 
     // Function to add two matrices
-    public int[][] add(int[][] A, int[][] B) {
-        int n = A.length;
+    public int[][] add(int[][] a, int[][] b) {
+        int n = a.length;
 
-        int[][] C = new int[n][n];
+        int[][] c = new int[n][n];
 
         for (int i = 0; i < n; i++) {
             for (int j = 0; j < n; j++) {
-                C[i][j] = A[i][j] + B[i][j];
+                c[i][j] = a[i][j] + b[i][j];
             }
         }
 
-        return C;
+        return c;
     }
 
     // Function to split parent matrix into child matrices
-    public void split(int[][] P, int[][] C, int iB, int jB) {
-        for (int i1 = 0, i2 = iB; i1 < C.length; i1++, i2++) {
-            for (int j1 = 0, j2 = jB; j1 < C.length; j1++, j2++) {
-                C[i1][j1] = P[i2][j2];
+    public void split(int[][] p, int[][] c, int iB, int jB) {
+        for (int i1 = 0, i2 = iB; i1 < c.length; i1++, i2++) {
+            for (int j1 = 0, j2 = jB; j1 < c.length; j1++, j2++) {
+                c[i1][j1] = p[i2][j2];
             }
         }
     }
 
     // Function to join child matrices into (to) parent matrix
-    public void join(int[][] C, int[][] P, int iB, int jB) {
-        for (int i1 = 0, i2 = iB; i1 < C.length; i1++, i2++) {
-            for (int j1 = 0, j2 = jB; j1 < C.length; j1++, j2++) {
-                P[i2][j2] = C[i1][j1];
+    public void join(int[][] c, int[][] p, int iB, int jB) {
+        for (int i1 = 0, i2 = iB; i1 < c.length; i1++, i2++) {
+            for (int j1 = 0, j2 = jB; j1 < c.length; j1++, j2++) {
+                p[i2][j2] = c[i1][j1];
             }
         }
     }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java b/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
index 5aba97eea1d8..1daac91c5b4b 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
@@ -32,8 +32,8 @@ static int knapSack(int W, int[] wt, int[] val, int n) {
     public static void main(String[] args) {
         int[] val = new int[] {60, 100, 120};
         int[] wt = new int[] {10, 20, 30};
-        int W = 50;
+        int w = 50;
         int n = val.length;
-        System.out.println(knapSack(W, wt, val, n));
+        System.out.println(knapSack(w, wt, val, n));
     }
 }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java b/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java
index bcd8b94a89ba..12cc29faa923 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java
@@ -58,9 +58,9 @@ public static int minimumCoins(int[] coins, int amount) {
         for (int i = 1; i <= amount; i++) {
             for (int coin : coins) {
                 if (coin <= i) {
-                    int sub_res = minimumCoins[i - coin];
-                    if (sub_res != Integer.MAX_VALUE && sub_res + 1 < minimumCoins[i]) {
-                        minimumCoins[i] = sub_res + 1;
+                    int subRes = minimumCoins[i - coin];
+                    if (subRes != Integer.MAX_VALUE && subRes + 1 < minimumCoins[i]) {
+                        minimumCoins[i] = subRes + 1;
                     }
                 }
             }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
index 92cd656f6bbd..e1f0aeabe14d 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
@@ -12,13 +12,13 @@ private KadaneAlgorithm() {
 
     public static boolean maxSum(int[] a, int predicted_answer) {
         int sum = a[0];
-        int running_sum = 0;
+        int runningSum = 0;
         for (int k : a) {
-            running_sum = running_sum + k;
+            runningSum = runningSum + k;
             // running sum of all the indexs are stored
-            sum = Math.max(sum, running_sum);
+            sum = Math.max(sum, runningSum);
             // the max is stored inorder to the get the maximum sum
-            if (running_sum < 0) running_sum = 0;
+            if (runningSum < 0) runningSum = 0;
             // if running sum is negative then it is initialized to zero
         }
         // for-each loop is used to iterate over the array and find the maximum subarray sum
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
index 7edfe1f5fde9..470833ce9c97 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java
@@ -21,18 +21,18 @@ private static int upperBound(int[] ar, int l, int r, int key) {
     }
 
     public static int lis(int[] array) {
-        int N = array.length;
-        if (N == 0) {
+        int len = array.length;
+        if (len == 0) {
             return 0;
         }
 
-        int[] tail = new int[N];
+        int[] tail = new int[len];
 
         // always points empty slot in tail
         int length = 1;
 
         tail[0] = array[0];
-        for (int i = 1; i < N; i++) {
+        for (int i = 1; i < len; i++) {
             // new smallest value
             if (array[i] < tail[0]) {
                 tail[0] = array[i];
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java b/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
index deb101c20073..01fa1d19609a 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
@@ -33,24 +33,24 @@ public static int minimalpartitions(String word) {
 
         int i;
         int j;
-        int L; // different looping variables
+        int subLen; // different looping variables
 
         // Every substring of length 1 is a palindrome
         for (i = 0; i < len; i++) {
             isPalindrome[i][i] = true;
         }
 
-        /* L is substring length. Build the solution in bottom up manner by considering all
+        /* subLen is substring length. Build the solution in bottom up manner by considering all
          * substrings of length starting from 2 to n. */
-        for (L = 2; L <= len; L++) {
-            // For substring of length L, set different possible starting indexes
-            for (i = 0; i < len - L + 1; i++) {
-                j = i + L - 1; // Ending index
-                // If L is 2, then we just need to
+        for (subLen = 2; subLen <= len; subLen++) {
+            // For substring of length subLen, set different possible starting indexes
+            for (i = 0; i < len - subLen + 1; i++) {
+                j = i + subLen - 1; // Ending index
+                // If subLen is 2, then we just need to
                 // compare two characters. Else need to
                 // check two corner characters and value
                 // of P[i+1][j-1]
-                if (L == 2) {
+                if (subLen == 2) {
                     isPalindrome[i][j] = (word.charAt(i) == word.charAt(j));
                 } else {
                     isPalindrome[i][j] = (word.charAt(i) == word.charAt(j)) && isPalindrome[i + 1][j - 1];
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java b/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
index 0ba25fa180f1..362ed5e252d2 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
@@ -6,13 +6,13 @@ private ShortestSuperSequence() {
     }
 
     // Function to find length of the
-    // shortest supersequence of X and Y.
-    static int shortestSuperSequence(String X, String Y) {
-        int m = X.length();
-        int n = Y.length();
+    // shortest supersequence of x and y.
+    static int shortestSuperSequence(String x, String y) {
+        int m = x.length();
+        int n = y.length();
 
         // find lcs
-        int l = lcs(X, Y, m, n);
+        int l = lcs(x, y, m, n);
 
         // Result is sum of input string
         // lengths - length of lcs
@@ -20,39 +20,39 @@ static int shortestSuperSequence(String X, String Y) {
     }
 
     // Returns length of LCS
-    // for X[0..m - 1], Y[0..n - 1]
-    static int lcs(String X, String Y, int m, int n) {
-        int[][] L = new int[m + 1][n + 1];
+    // for x[0..m - 1], y[0..n - 1]
+    static int lcs(String x, String y, int m, int n) {
+        int[][] lN = new int[m + 1][n + 1];
         int i;
         int j;
 
-        // Following steps build L[m + 1][n + 1]
+        // Following steps build lN[m + 1][n + 1]
         // in bottom up fashion. Note that
-        // L[i][j] contains length of LCS
-        // of X[0..i - 1]and Y[0..j - 1]
+        // lN[i][j] contains length of lNCS
+        // of x[0..i - 1]and y[0..j - 1]
         for (i = 0; i <= m; i++) {
             for (j = 0; j <= n; j++) {
                 if (i == 0 || j == 0) {
-                    L[i][j] = 0;
-                } else if (X.charAt(i - 1) == Y.charAt(j - 1)) {
-                    L[i][j] = L[i - 1][j - 1] + 1;
+                    lN[i][j] = 0;
+                } else if (x.charAt(i - 1) == y.charAt(j - 1)) {
+                    lN[i][j] = lN[i - 1][j - 1] + 1;
                 } else {
-                    L[i][j] = Math.max(L[i - 1][j], L[i][j - 1]);
+                    lN[i][j] = Math.max(lN[i - 1][j], lN[i][j - 1]);
                 }
             }
         }
 
-        // L[m][n] contains length of LCS
-        // for X[0..n - 1] and Y[0..m - 1]
-        return L[m][n];
+        // lN[m][n] contains length of LCS
+        // for x[0..n - 1] and y[0..m - 1]
+        return lN[m][n];
     }
 
     // Driver code
     public static void main(String[] args) {
-        String X = "AGGTAB";
-        String Y = "GXTXAYB";
+        String x = "AGGTAB";
+        String y = "GXTXAYB";
 
         System.out.println("Length of the shortest "
-            + "supersequence is " + shortestSuperSequence(X, Y));
+            + "supersequence is " + shortestSuperSequence(x, y));
     }
 }
diff --git a/src/main/java/com/thealgorithms/maths/CrossCorrelation.java b/src/main/java/com/thealgorithms/maths/CrossCorrelation.java
index d3a2303502fa..eeb4d6d1717a 100644
--- a/src/main/java/com/thealgorithms/maths/CrossCorrelation.java
+++ b/src/main/java/com/thealgorithms/maths/CrossCorrelation.java
@@ -22,7 +22,7 @@ private CrossCorrelation() {
     public static double[] crossCorrelation(double[] x, double[] y) {
         // The result signal's length is the sum of the input signals' lengths minus 1
         double[] result = new double[x.length + y.length - 1];
-        int N = result.length;
+        int n = result.length;
 
         /*
         To find the cross-correlation between 2 discrete signals x & y, we start by "placing" the second signal
@@ -60,13 +60,13 @@ and for every new position (i++) of the result signal, we shift y signal one pos
 
 
 
-        To find the result[i] value for each i:0->N-1, the positions of x-signal in which the 2 signals meet
+        To find the result[i] value for each i:0->n-1, the positions of x-signal in which the 2 signals meet
         are calculated: kMin<=k<=kMax.
         The variable 'yStart' indicates the starting index of y in each sum calculation.
         The variable 'count' increases the index of y-signal by 1, to move to the next value.
          */
         int yStart = y.length;
-        for (int i = 0; i < N; i++) {
+        for (int i = 0; i < n; i++) {
             result[i] = 0;
 
             int kMin = Math.max(i - (y.length - 1), 0);
diff --git a/src/main/java/com/thealgorithms/maths/FFT.java b/src/main/java/com/thealgorithms/maths/FFT.java
index 573275544439..7ca7543d7985 100644
--- a/src/main/java/com/thealgorithms/maths/FFT.java
+++ b/src/main/java/com/thealgorithms/maths/FFT.java
@@ -186,16 +186,16 @@ public Complex divide(double n) {
     public static ArrayList<Complex> fft(ArrayList<Complex> x, boolean inverse) {
         /* Pad the signal with zeros if necessary */
         paddingPowerOfTwo(x);
-        int N = x.size();
-        int log2N = findLog2(N);
-        x = fftBitReversal(N, log2N, x);
+        int n = x.size();
+        int log2n = findLog2(n);
+        x = fftBitReversal(n, log2n, x);
         int direction = inverse ? -1 : 1;
 
         /* Main loop of the algorithm */
-        for (int len = 2; len <= N; len *= 2) {
+        for (int len = 2; len <= n; len *= 2) {
             double angle = -2 * Math.PI / len * direction;
             Complex wlen = new Complex(Math.cos(angle), Math.sin(angle));
-            for (int i = 0; i < N; i += len) {
+            for (int i = 0; i < n; i += len) {
                 Complex w = new Complex(1, 0);
                 for (int j = 0; j < len / 2; j++) {
                     Complex u = x.get(i + j);
@@ -206,24 +206,24 @@ public static ArrayList<Complex> fft(ArrayList<Complex> x, boolean inverse) {
                 }
             }
         }
-        x = inverseFFT(N, inverse, x);
+        x = inverseFFT(n, inverse, x);
         return x;
     }
 
-    /* Find the log2(N) */
-    public static int findLog2(int N) {
-        int log2N = 0;
-        while ((1 << log2N) < N) {
-            log2N++;
+    /* Find the log2(n) */
+    public static int findLog2(int n) {
+        int log2n = 0;
+        while ((1 << log2n) < n) {
+            log2n++;
         }
-        return log2N;
+        return log2n;
     }
 
     /* Swap the values of the signal with bit-reversal method */
-    public static ArrayList<Complex> fftBitReversal(int N, int log2N, ArrayList<Complex> x) {
+    public static ArrayList<Complex> fftBitReversal(int n, int log2n, ArrayList<Complex> x) {
         int reverse;
-        for (int i = 0; i < N; i++) {
-            reverse = reverseBits(i, log2N);
+        for (int i = 0; i < n; i++) {
+            reverse = reverseBits(i, log2n);
             if (i < reverse) {
                 Collections.swap(x, i, reverse);
             }
@@ -231,12 +231,12 @@ public static ArrayList<Complex> fftBitReversal(int N, int log2N, ArrayList<Comp
         return x;
     }
 
-    /* Divide by N if we want the inverse FFT */
-    public static ArrayList<Complex> inverseFFT(int N, boolean inverse, ArrayList<Complex> x) {
+    /* Divide by n if we want the inverse FFT */
+    public static ArrayList<Complex> inverseFFT(int n, boolean inverse, ArrayList<Complex> x) {
         if (inverse) {
             for (int i = 0; i < x.size(); i++) {
                 Complex z = x.get(i);
-                x.set(i, z.divide(N));
+                x.set(i, z.divide(n));
             }
         }
         return x;
@@ -247,7 +247,7 @@ public static ArrayList<Complex> inverseFFT(int N, boolean inverse, ArrayList<Co
      * FFT algorithm.
      *
      * <p>
-     * E.g. num = 13 = 00001101 in binary log2N = 8 Then reversed = 176 =
+     * E.g. num = 13 = 00001101 in binary log2n = 8 Then reversed = 176 =
      * 10110000 in binary
      *
      * <p>
@@ -255,14 +255,14 @@ public static ArrayList<Complex> inverseFFT(int N, boolean inverse, ArrayList<Co
      * https://www.geeksforgeeks.org/write-an-efficient-c-program-to-reverse-bits-of-a-number/
      *
      * @param num The integer you want to reverse its bits.
-     * @param log2N The number of bits you want to reverse.
+     * @param log2n The number of bits you want to reverse.
      * @return The reversed number
      */
-    private static int reverseBits(int num, int log2N) {
+    private static int reverseBits(int num, int log2n) {
         int reversed = 0;
-        for (int i = 0; i < log2N; i++) {
+        for (int i = 0; i < log2n; i++) {
             if ((num & (1 << i)) != 0) {
-                reversed |= 1 << (log2N - 1 - i);
+                reversed |= 1 << (log2n - 1 - i);
             }
         }
         return reversed;
diff --git a/src/main/java/com/thealgorithms/maths/FFTBluestein.java b/src/main/java/com/thealgorithms/maths/FFTBluestein.java
index ca9517eeb673..388de6fed3eb 100644
--- a/src/main/java/com/thealgorithms/maths/FFTBluestein.java
+++ b/src/main/java/com/thealgorithms/maths/FFTBluestein.java
@@ -26,8 +26,8 @@ private FFTBluestein() {
      * @param inverse True if you want to find the inverse FFT.
      */
     public static void fftBluestein(ArrayList<FFT.Complex> x, boolean inverse) {
-        int N = x.size();
-        int bnSize = 2 * N - 1;
+        int n = x.size();
+        int bnSize = 2 * n - 1;
         int direction = inverse ? -1 : 1;
         ArrayList<FFT.Complex> an = new ArrayList<>();
         ArrayList<FFT.Complex> bn = new ArrayList<>();
@@ -38,32 +38,32 @@ public static void fftBluestein(ArrayList<FFT.Complex> x, boolean inverse) {
             bn.add(new FFT.Complex());
         }
 
-        for (int i = 0; i < N; i++) {
-            double angle = (i - N + 1) * (i - N + 1) * Math.PI / N * direction;
+        for (int i = 0; i < n; i++) {
+            double angle = (i - n + 1) * (i - n + 1) * Math.PI / n * direction;
             bn.set(i, new FFT.Complex(Math.cos(angle), Math.sin(angle)));
             bn.set(bnSize - i - 1, new FFT.Complex(Math.cos(angle), Math.sin(angle)));
         }
 
         /* Initialization of the a(n) sequence */
-        for (int i = 0; i < N; i++) {
-            double angle = -i * i * Math.PI / N * direction;
+        for (int i = 0; i < n; i++) {
+            double angle = -i * i * Math.PI / n * direction;
             an.add(x.get(i).multiply(new FFT.Complex(Math.cos(angle), Math.sin(angle))));
         }
 
         ArrayList<FFT.Complex> convolution = ConvolutionFFT.convolutionFFT(an, bn);
 
         /* The final multiplication of the convolution with the b*(k) factor  */
-        for (int i = 0; i < N; i++) {
-            double angle = -1 * i * i * Math.PI / N * direction;
+        for (int i = 0; i < n; i++) {
+            double angle = -1 * i * i * Math.PI / n * direction;
             FFT.Complex bk = new FFT.Complex(Math.cos(angle), Math.sin(angle));
-            x.set(i, bk.multiply(convolution.get(i + N - 1)));
+            x.set(i, bk.multiply(convolution.get(i + n - 1)));
         }
 
-        /* Divide by N if we want the inverse FFT */
+        /* Divide by n if we want the inverse FFT */
         if (inverse) {
-            for (int i = 0; i < N; i++) {
+            for (int i = 0; i < n; i++) {
                 FFT.Complex z = x.get(i);
-                x.set(i, z.divide(N));
+                x.set(i, z.divide(n));
             }
         }
     }
diff --git a/src/main/java/com/thealgorithms/maths/KeithNumber.java b/src/main/java/com/thealgorithms/maths/KeithNumber.java
index c2d64dcad493..1756cfbae91b 100644
--- a/src/main/java/com/thealgorithms/maths/KeithNumber.java
+++ b/src/main/java/com/thealgorithms/maths/KeithNumber.java
@@ -26,24 +26,24 @@ static boolean isKeith(int x) {
         }
         // reverse the List
         Collections.reverse(terms);
-        int next_term = 0;
+        int nextTerm = 0;
         int i = n;
         // finds next term for the series
         // loop executes until the condition returns true
-        while (next_term < x) {
-            next_term = 0;
+        while (nextTerm < x) {
+            nextTerm = 0;
             // next term is the sum of previous n terms (it depends on number of digits the number
             // has)
             for (int j = 1; j <= n; j++) {
-                next_term = next_term + terms.get(i - j);
+                nextTerm = nextTerm + terms.get(i - j);
             }
-            terms.add(next_term);
+            terms.add(nextTerm);
             i++;
         }
         // when the control comes out of the while loop, there will be two conditions:
-        // either next_term will be equal to x or greater than x
+        // either nextTerm will be equal to x or greater than x
         // if equal, the given number is Keith, else not
-        return (next_term == x);
+        return (nextTerm == x);
     }
 
     // driver code
diff --git a/src/main/java/com/thealgorithms/maths/LongDivision.java b/src/main/java/com/thealgorithms/maths/LongDivision.java
index 2191bf840a9b..45e97b1c14c3 100644
--- a/src/main/java/com/thealgorithms/maths/LongDivision.java
+++ b/src/main/java/com/thealgorithms/maths/LongDivision.java
@@ -12,59 +12,59 @@ public final class LongDivision {
     private LongDivision() {
     }
     public static int divide(int dividend, int divisor) {
-        long new_dividend_1 = dividend;
-        long new_divisor_1 = divisor;
+        long newDividend1 = dividend;
+        long newDivisor1 = divisor;
 
         if (divisor == 0) {
             return 0;
         }
         if (dividend < 0) {
-            new_dividend_1 = new_dividend_1 * -1;
+            newDividend1 = newDividend1 * -1;
         }
         if (divisor < 0) {
-            new_divisor_1 = new_divisor_1 * -1;
+            newDivisor1 = newDivisor1 * -1;
         }
 
-        if (dividend == 0 || new_dividend_1 < new_divisor_1) {
+        if (dividend == 0 || newDividend1 < newDivisor1) {
             return 0;
         }
 
         StringBuilder answer = new StringBuilder();
 
-        String dividend_string = "" + new_dividend_1;
-        int last_index = 0;
+        String dividendString = "" + newDividend1;
+        int lastIndex = 0;
 
         String remainder = "";
 
-        for (int i = 0; i < dividend_string.length(); i++) {
-            String part_v1 = remainder + "" + dividend_string.substring(last_index, i + 1);
-            long part_1 = Long.parseLong(part_v1);
-            if (part_1 > new_divisor_1) {
+        for (int i = 0; i < dividendString.length(); i++) {
+            String partV1 = remainder + "" + dividendString.substring(lastIndex, i + 1);
+            long part1 = Long.parseLong(partV1);
+            if (part1 > newDivisor1) {
                 int quotient = 0;
-                while (part_1 >= new_divisor_1) {
-                    part_1 = part_1 - new_divisor_1;
+                while (part1 >= newDivisor1) {
+                    part1 = part1 - newDivisor1;
                     quotient++;
                 }
                 answer.append(quotient);
-            } else if (part_1 == new_divisor_1) {
+            } else if (part1 == newDivisor1) {
                 int quotient = 0;
-                while (part_1 >= new_divisor_1) {
-                    part_1 = part_1 - new_divisor_1;
+                while (part1 >= newDivisor1) {
+                    part1 = part1 - newDivisor1;
                     quotient++;
                 }
                 answer.append(quotient);
-            } else if (part_1 == 0) {
+            } else if (part1 == 0) {
                 answer.append(0);
-            } else if (part_1 < new_divisor_1) {
+            } else if (part1 < newDivisor1) {
                 answer.append(0);
             }
-            if (!(part_1 == 0)) {
-                remainder = String.valueOf(part_1);
+            if (!(part1 == 0)) {
+                remainder = String.valueOf(part1);
             } else {
                 remainder = "";
             }
 
-            last_index++;
+            lastIndex++;
         }
 
         if ((dividend < 0 && divisor > 0) || (dividend > 0 && divisor < 0)) {
diff --git a/src/main/java/com/thealgorithms/maths/MagicSquare.java b/src/main/java/com/thealgorithms/maths/MagicSquare.java
index 7e0ff4da6da7..de0afc148982 100644
--- a/src/main/java/com/thealgorithms/maths/MagicSquare.java
+++ b/src/main/java/com/thealgorithms/maths/MagicSquare.java
@@ -18,32 +18,32 @@ public static void main(String[] args) {
             System.exit(0);
         }
 
-        int[][] magic_square = new int[num][num];
+        int[][] magicSquare = new int[num][num];
 
-        int row_num = num / 2;
-        int col_num = num - 1;
-        magic_square[row_num][col_num] = 1;
+        int rowNum = num / 2;
+        int colNum = num - 1;
+        magicSquare[rowNum][colNum] = 1;
 
         for (int i = 2; i <= num * num; i++) {
-            if (magic_square[(row_num - 1 + num) % num][(col_num + 1) % num] == 0) {
-                row_num = (row_num - 1 + num) % num;
-                col_num = (col_num + 1) % num;
+            if (magicSquare[(rowNum - 1 + num) % num][(colNum + 1) % num] == 0) {
+                rowNum = (rowNum - 1 + num) % num;
+                colNum = (colNum + 1) % num;
             } else {
-                col_num = (col_num - 1 + num) % num;
+                colNum = (colNum - 1 + num) % num;
             }
-            magic_square[row_num][col_num] = i;
+            magicSquare[rowNum][colNum] = i;
         }
 
         // print the square
         for (int i = 0; i < num; i++) {
             for (int j = 0; j < num; j++) {
-                if (magic_square[i][j] < 10) {
+                if (magicSquare[i][j] < 10) {
                     System.out.print(" ");
                 }
-                if (magic_square[i][j] < 100) {
+                if (magicSquare[i][j] < 100) {
                     System.out.print(" ");
                 }
-                System.out.print(magic_square[i][j] + " ");
+                System.out.print(magicSquare[i][j] + " ");
             }
             System.out.println();
         }
diff --git a/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java b/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java
index ef02c5759c03..79bc112902c4 100644
--- a/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java
+++ b/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java
@@ -19,19 +19,19 @@ public static void main(String[] args) {
         SimpsonIntegration integration = new SimpsonIntegration();
 
         // Give random data for the example purposes
-        int N = 16;
+        int n = 16;
         double a = 1;
         double b = 3;
 
-        // Check so that N is even
-        if (N % 2 != 0) {
-            System.out.println("N must be even number for Simpsons method. Aborted");
+        // Check so that n is even
+        if (n % 2 != 0) {
+            System.out.println("n must be even number for Simpsons method. Aborted");
             System.exit(1);
         }
 
         // Calculate step h and evaluate the integral
-        double h = (b - a) / (double) N;
-        double integralEvaluation = integration.simpsonsMethod(N, h, a);
+        double h = (b - a) / (double) n;
+        double integralEvaluation = integration.simpsonsMethod(n, h, a);
         System.out.println("The integral is equal to: " + integralEvaluation);
     }
 
@@ -45,13 +45,13 @@ public static void main(String[] args) {
      *
      * @return result of the integral evaluation
      */
-    public double simpsonsMethod(int N, double h, double a) {
+    public double simpsonsMethod(int n, double h, double a) {
         TreeMap<Integer, Double> data = new TreeMap<>(); // Key: i, Value: f(xi)
         double temp;
         double xi = a; // Initialize the variable xi = x0 + 0*h
 
         // Create the table of xi and yi points
-        for (int i = 0; i <= N; i++) {
+        for (int i = 0; i <= n; i++) {
             temp = f(xi); // Get the value of the function at that point
             data.put(i, temp);
             xi += h; // Increase the xi to the next point
diff --git a/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java b/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java
index 8a1bb1488eab..8b93702b9514 100644
--- a/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java
+++ b/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java
@@ -111,15 +111,15 @@ public static void main(String[] args) {
 
     static void test() {
         // Create two vectors
-        VectorCrossProduct A = new VectorCrossProduct(1, -2, 3);
-        VectorCrossProduct B = new VectorCrossProduct(2, 0, 3);
+        VectorCrossProduct a = new VectorCrossProduct(1, -2, 3);
+        VectorCrossProduct b = new VectorCrossProduct(2, 0, 3);
 
         // Determine cross product
-        VectorCrossProduct crossProd = A.crossProduct(B);
+        VectorCrossProduct crossProd = a.crossProduct(b);
         crossProd.displayVector();
 
         // Determine dot product
-        int dotProd = A.dotProduct(B);
-        System.out.println("Dot Product of A and B: " + dotProd);
+        int dotProd = a.dotProduct(b);
+        System.out.println("Dot Product of a and b: " + dotProd);
     }
 }
diff --git a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
index a78bbbf34278..15093549871b 100644
--- a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
+++ b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
@@ -21,27 +21,27 @@ public static void main(String[] args) {
 
             // To insert a new element(we are creating a new array)
             System.out.println("Enter the index at which the element should be inserted");
-            int insert_pos = s.nextInt();
+            int insertPos = s.nextInt();
             System.out.println("Enter the element to be inserted");
             int ins = s.nextInt();
             int size2 = size + 1;
             int[] b = new int[size2];
             for (i = 0; i < size2; i++) {
-                if (i <= insert_pos) {
+                if (i <= insertPos) {
                     b[i] = a[i];
                 } else {
                     b[i] = a[i - 1];
                 }
             }
-            b[insert_pos] = ins;
+            b[insertPos] = ins;
             for (i = 0; i < size2; i++) {
                 System.out.println(b[i]);
             }
 
             // To delete an element given the index
             System.out.println("Enter the index at which element is to be deleted");
-            int del_pos = s.nextInt();
-            for (i = del_pos; i < size2 - 1; i++) {
+            int delPos = s.nextInt();
+            for (i = delPos; i < size2 - 1; i++) {
                 b[i] = b[i + 1];
             }
             for (i = 0; i < size2 - 1; i++) {
diff --git a/src/main/java/com/thealgorithms/others/PageRank.java b/src/main/java/com/thealgorithms/others/PageRank.java
index 960034fdb701..c7be7a9882bc 100644
--- a/src/main/java/com/thealgorithms/others/PageRank.java
+++ b/src/main/java/com/thealgorithms/others/PageRank.java
@@ -28,20 +28,20 @@ public static void main(String[] args) {
     public double[] pagerank = new double[10];
 
     public void calc(double totalNodes) {
-        double InitialPageRank;
-        double OutgoingLinks = 0;
-        double DampingFactor = 0.85;
-        double[] TempPageRank = new double[10];
-        int ExternalNodeNumber;
-        int InternalNodeNumber;
+        double initialPageRank;
+        double outgoingLinks = 0;
+        double dampingFactor = 0.85;
+        double[] tempPageRank = new double[10];
+        int externalNodeNumber;
+        int internalNodeNumber;
         int k = 1; // For Traversing
-        int ITERATION_STEP = 1;
-        InitialPageRank = 1 / totalNodes;
-        System.out.printf(" Total Number of Nodes :" + totalNodes + "\t Initial PageRank  of All Nodes :" + InitialPageRank + "\n");
+        int iterationStep = 1;
+        initialPageRank = 1 / totalNodes;
+        System.out.printf(" Total Number of Nodes :" + totalNodes + "\t Initial PageRank  of All Nodes :" + initialPageRank + "\n");
 
         // 0th ITERATION _ OR _ INITIALIZATION PHASE //
         for (k = 1; k <= totalNodes; k++) {
-            this.pagerank[k] = InitialPageRank;
+            this.pagerank[k] = initialPageRank;
         }
         System.out.print("\n Initial PageRank Values , 0th Step \n");
 
@@ -49,40 +49,40 @@ public void calc(double totalNodes) {
             System.out.printf(" Page Rank of " + k + " is :\t" + this.pagerank[k] + "\n");
         }
 
-        while (ITERATION_STEP <= 2) { // Iterations
+        while (iterationStep <= 2) { // Iterations
             // Store the PageRank for All Nodes in Temporary Array
             for (k = 1; k <= totalNodes; k++) {
-                TempPageRank[k] = this.pagerank[k];
+                tempPageRank[k] = this.pagerank[k];
                 this.pagerank[k] = 0;
             }
 
-            for (InternalNodeNumber = 1; InternalNodeNumber <= totalNodes; InternalNodeNumber++) {
-                for (ExternalNodeNumber = 1; ExternalNodeNumber <= totalNodes; ExternalNodeNumber++) {
-                    if (this.path[ExternalNodeNumber][InternalNodeNumber] == 1) {
+            for (internalNodeNumber = 1; internalNodeNumber <= totalNodes; internalNodeNumber++) {
+                for (externalNodeNumber = 1; externalNodeNumber <= totalNodes; externalNodeNumber++) {
+                    if (this.path[externalNodeNumber][internalNodeNumber] == 1) {
                         k = 1;
-                        OutgoingLinks = 0; // Count the Number of Outgoing Links for each ExternalNodeNumber
+                        outgoingLinks = 0; // Count the Number of Outgoing Links for each externalNodeNumber
                         while (k <= totalNodes) {
-                            if (this.path[ExternalNodeNumber][k] == 1) {
-                                OutgoingLinks = OutgoingLinks + 1; // Counter for Outgoing Links
+                            if (this.path[externalNodeNumber][k] == 1) {
+                                outgoingLinks = outgoingLinks + 1; // Counter for Outgoing Links
                             }
                             k = k + 1;
                         }
                         // Calculate PageRank
-                        this.pagerank[InternalNodeNumber] += TempPageRank[ExternalNodeNumber] * (1 / OutgoingLinks);
+                        this.pagerank[internalNodeNumber] += tempPageRank[externalNodeNumber] * (1 / outgoingLinks);
                     }
                 }
-                System.out.printf("\n After " + ITERATION_STEP + "th Step \n");
+                System.out.printf("\n After " + iterationStep + "th Step \n");
 
                 for (k = 1; k <= totalNodes; k++) {
                     System.out.printf(" Page Rank of " + k + " is :\t" + this.pagerank[k] + "\n");
                 }
 
-                ITERATION_STEP = ITERATION_STEP + 1;
+                iterationStep = iterationStep + 1;
             }
 
             // Add the Damping Factor to PageRank
             for (k = 1; k <= totalNodes; k++) {
-                this.pagerank[k] = (1 - DampingFactor) + DampingFactor * this.pagerank[k];
+                this.pagerank[k] = (1 - dampingFactor) + dampingFactor * this.pagerank[k];
             }
 
             // Display PageRank
diff --git a/src/main/java/com/thealgorithms/others/ReturnSubsequence.java b/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
index cf2f091a102f..81bd051ca365 100644
--- a/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
+++ b/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
@@ -30,18 +30,18 @@ private static String[] returnSubsequence(String givenString) {
             ans[0] = "";
             return ans;
         }
-        String[] SmallAns = returnSubsequence(givenString.substring(1)); // recursive call to get subsequences of substring starting from index
+        String[] smallAns = returnSubsequence(givenString.substring(1)); // recursive call to get subsequences of substring starting from index
         // position=1
 
-        String[] ans = new String[2 * SmallAns.length]; // Our answer will be an array off string of size=2*SmallAns
+        String[] ans = new String[2 * smallAns.length]; // Our answer will be an array off string of size=2*smallAns
         int i = 0;
-        for (; i < SmallAns.length; i++) {
-            ans[i] = SmallAns[i]; // Copying all the strings present in SmallAns to ans string array
+        for (; i < smallAns.length; i++) {
+            ans[i] = smallAns[i]; // Copying all the strings present in smallAns to ans string array
         }
-        for (int k = 0; k < SmallAns.length; k++) {
-            ans[k + SmallAns.length] = givenString.charAt(0) + SmallAns[k]; // Insert character at index=0 of the given
+        for (int k = 0; k < smallAns.length; k++) {
+            ans[k + smallAns.length] = givenString.charAt(0) + smallAns[k]; // Insert character at index=0 of the given
                                                                             // substring in front of every string
-            // in SmallAns
+            // in smallAns
         }
         return ans;
     }
diff --git a/src/main/java/com/thealgorithms/others/RootPrecision.java b/src/main/java/com/thealgorithms/others/RootPrecision.java
index a804f8f69db4..bc195ffca5ae 100644
--- a/src/main/java/com/thealgorithms/others/RootPrecision.java
+++ b/src/main/java/com/thealgorithms/others/RootPrecision.java
@@ -10,27 +10,27 @@ public static void main(String[] args) {
         // take input
         Scanner scn = new Scanner(System.in);
 
-        // N is the input number
-        int N = scn.nextInt();
+        // n is the input number
+        int n = scn.nextInt();
 
-        // P is precision value for eg - P is 3 in 2.564 and 5 in 3.80870.
-        int P = scn.nextInt();
-        System.out.println(squareRoot(N, P));
+        // p is precision value for eg - p is 3 in 2.564 and 5 in 3.80870.
+        int p = scn.nextInt();
+        System.out.println(squareRoot(n, p));
 
         scn.close();
     }
 
-    public static double squareRoot(int N, int P) {
+    public static double squareRoot(int n, int p) {
         // rv means return value
         double rv;
 
-        double root = Math.pow(N, 0.5);
+        double root = Math.pow(n, 0.5);
 
         // calculate precision to power of 10 and then multiply it with root value.
-        int precision = (int) Math.pow(10, P);
+        int precision = (int) Math.pow(10, p);
         root = root * precision;
         /*typecast it into integer then divide by precision and again typecast into double
-    so as to have decimal points upto P precision */
+    so as to have decimal points upto p precision */
 
         rv = (int) root;
         return rv / precision;
diff --git a/src/main/java/com/thealgorithms/others/Sudoku.java b/src/main/java/com/thealgorithms/others/Sudoku.java
index d27a1648b743..0839a376c5de 100644
--- a/src/main/java/com/thealgorithms/others/Sudoku.java
+++ b/src/main/java/com/thealgorithms/others/Sudoku.java
@@ -86,16 +86,16 @@ public static boolean solveSudoku(int[][] board, int n) {
         return false;
     }
 
-    public static void print(int[][] board, int N) {
+    public static void print(int[][] board, int n) {
         // We got the answer, just print it
-        for (int r = 0; r < N; r++) {
-            for (int d = 0; d < N; d++) {
+        for (int r = 0; r < n; r++) {
+            for (int d = 0; d < n; d++) {
                 System.out.print(board[r][d]);
                 System.out.print(" ");
             }
             System.out.print("\n");
 
-            if ((r + 1) % (int) Math.sqrt(N) == 0) {
+            if ((r + 1) % (int) Math.sqrt(n) == 0) {
                 System.out.print("");
             }
         }
@@ -114,11 +114,11 @@ public static void main(String[] args) {
             {0, 0, 0, 0, 0, 0, 0, 7, 4},
             {0, 0, 5, 2, 0, 6, 3, 0, 0},
         };
-        int N = board.length;
+        int n = board.length;
 
-        if (solveSudoku(board, N)) {
+        if (solveSudoku(board, n)) {
             // print solution
-            print(board, N);
+            print(board, n);
         } else {
             System.out.println("No solution");
         }
diff --git a/src/main/java/com/thealgorithms/searches/KMPSearch.java b/src/main/java/com/thealgorithms/searches/KMPSearch.java
index 38a4c74dee31..3648a4b08b86 100644
--- a/src/main/java/com/thealgorithms/searches/KMPSearch.java
+++ b/src/main/java/com/thealgorithms/searches/KMPSearch.java
@@ -3,25 +3,25 @@
 class KMPSearch {
 
     int kmpSearch(String pat, String txt) {
-        int M = pat.length();
-        int N = txt.length();
+        int m = pat.length();
+        int n = txt.length();
 
         // create lps[] that will hold the longest
         // prefix suffix values for pattern
-        int[] lps = new int[M];
+        int[] lps = new int[m];
         int j = 0; // index for pat[]
 
         // Preprocess the pattern (calculate lps[]
         // array)
-        computeLPSArray(pat, M, lps);
+        computeLPSArray(pat, m, lps);
 
         int i = 0; // index for txt[]
-        while ((N - i) >= (M - j)) {
+        while ((n - i) >= (m - j)) {
             if (pat.charAt(j) == txt.charAt(i)) {
                 j++;
                 i++;
             }
-            if (j == M) {
+            if (j == m) {
                 System.out.println("Found pattern "
                     + "at index " + (i - j));
                 int index = (i - j);
@@ -29,7 +29,7 @@ int kmpSearch(String pat, String txt) {
                 return index;
             }
             // mismatch after j matches
-            else if (i < N && pat.charAt(j) != txt.charAt(i)) {
+            else if (i < n && pat.charAt(j) != txt.charAt(i)) {
                 // Do not match lps[0..lps[j-1]] characters,
                 // they will match anyway
                 if (j != 0)
@@ -42,14 +42,14 @@ else if (i < N && pat.charAt(j) != txt.charAt(i)) {
         return -1;
     }
 
-    void computeLPSArray(String pat, int M, int[] lps) {
+    void computeLPSArray(String pat, int m, int[] lps) {
         // length of the previous longest prefix suffix
         int len = 0;
         int i = 1;
         lps[0] = 0; // lps[0] is always 0
 
-        // the loop calculates lps[i] for i = 1 to M-1
-        while (i < M) {
+        // the loop calculates lps[i] for i = 1 to m-1
+        while (i < m) {
             if (pat.charAt(i) == pat.charAt(len)) {
                 len++;
                 lps[i] = len;
diff --git a/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java b/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
index 8fb3f4f68986..cdd256150871 100644
--- a/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
@@ -18,7 +18,7 @@ private OrderAgnosticBinarySearch() {
     static int binSearchAlgo(int[] arr, int start, int end, int target) {
 
         // Checking whether the given array is ascending order
-        boolean AscOrd = arr[start] < arr[end];
+        boolean ascOrd = arr[start] < arr[end];
 
         while (start <= end) {
             int middle = start + (end - start) / 2;
@@ -27,7 +27,7 @@ static int binSearchAlgo(int[] arr, int start, int end, int target) {
             if (arr[middle] == target) return middle; // returns the index of the middle element
 
             // Ascending order
-            if (AscOrd) {
+            if (ascOrd) {
                 if (arr[middle] < target)
                     start = middle + 1;
                 else
diff --git a/src/main/java/com/thealgorithms/sorts/DNFSort.java b/src/main/java/com/thealgorithms/sorts/DNFSort.java
index 6e89bb65ad32..50ba8c89715b 100644
--- a/src/main/java/com/thealgorithms/sorts/DNFSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DNFSort.java
@@ -6,9 +6,9 @@ private DNFSort() {
 
     // Sort the input array, the array is assumed to
     // have values in {0, 1, 2}
-    static void sort012(int[] a, int arr_size) {
+    static void sort012(int[] a, int arrSize) {
         int low = 0;
-        int high = arr_size - 1;
+        int high = arrSize - 1;
         int mid = 0;
         int temp;
         while (mid <= high) {
@@ -38,8 +38,8 @@ static void sort012(int[] a, int arr_size) {
     }
 
     /* Utility function to print array arr[] */
-    static void printArray(int[] arr, int arr_size) {
-        for (int i = 0; i < arr_size; i++) {
+    static void printArray(int[] arr, int arrSize) {
+        for (int i = 0; i < arrSize; i++) {
             System.out.print(arr[i] + " ");
         }
         System.out.println();
@@ -48,9 +48,9 @@ static void printArray(int[] arr, int arr_size) {
     /*Driver function to check for above functions*/
     public static void main(String[] args) {
         int[] arr = {0, 1, 1, 0, 1, 2, 1, 2, 0, 0, 0, 1};
-        int arr_size = arr.length;
-        sort012(arr, arr_size);
+        int arrSize = arr.length;
+        sort012(arr, arrSize);
         System.out.println("Array after seggregation ");
-        printArray(arr, arr_size);
+        printArray(arr, arrSize);
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/SwapSort.java b/src/main/java/com/thealgorithms/sorts/SwapSort.java
index b10728b6a5c3..08ce988578f3 100644
--- a/src/main/java/com/thealgorithms/sorts/SwapSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SwapSort.java
@@ -11,10 +11,10 @@ public class SwapSort implements SortAlgorithm {
 
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
-        int LENGTH = array.length;
+        int len = array.length;
         int index = 0;
 
-        while (index < LENGTH - 1) {
+        while (index < len - 1) {
             int amountSmallerElements = this.getSmallerElementCount(array, index);
 
             if (amountSmallerElements > 0 && index != amountSmallerElements) {
diff --git a/src/main/java/com/thealgorithms/strings/MyAtoi.java b/src/main/java/com/thealgorithms/strings/MyAtoi.java
index 119d75e4d828..0aed13f936a7 100644
--- a/src/main/java/com/thealgorithms/strings/MyAtoi.java
+++ b/src/main/java/com/thealgorithms/strings/MyAtoi.java
@@ -8,13 +8,13 @@ private MyAtoi() {
     }
     public static int myAtoi(String s) {
         s = s.trim();
-        char[] char_1 = s.toCharArray();
+        char[] char1 = s.toCharArray();
         String number = "";
         boolean negative = false;
         boolean zero = false;
         boolean isDigit = false;
 
-        for (char ch : char_1) {
+        for (char ch : char1) {
             if (Character.isDigit(ch)) {
                 if (number.length() > 1 && !isDigit) {
                     number = "0";
diff --git a/src/main/java/com/thealgorithms/strings/WordLadder.java b/src/main/java/com/thealgorithms/strings/WordLadder.java
index 025c43b15466..16d4e0a02452 100644
--- a/src/main/java/com/thealgorithms/strings/WordLadder.java
+++ b/src/main/java/com/thealgorithms/strings/WordLadder.java
@@ -67,24 +67,24 @@ public static int ladderLength(String beginWord, String endWord, List<String> wo
             int size = queue.size();
             for (int i = 0; i < size; i++) {
                 String curr = queue.poll();
-                char[] words_chars = curr.toCharArray();
-                for (int j = 0; j < words_chars.length; j++) {
-                    char original_chars = words_chars[j];
+                char[] wordsChars = curr.toCharArray();
+                for (int j = 0; j < wordsChars.length; j++) {
+                    char originalChars = wordsChars[j];
                     for (char c = 'a'; c <= 'z'; c++) {
-                        if (words_chars[j] == c) {
+                        if (wordsChars[j] == c) {
                             continue;
                         }
-                        words_chars[j] = c;
-                        String new_word = String.valueOf(words_chars);
-                        if (new_word.equals(endWord)) {
+                        wordsChars[j] = c;
+                        String newWord = String.valueOf(wordsChars);
+                        if (newWord.equals(endWord)) {
                             return level + 1;
                         }
-                        if (set.contains(new_word)) {
-                            set.remove(new_word);
-                            queue.offer(new_word);
+                        if (set.contains(newWord)) {
+                            set.remove(newWord);
+                            queue.offer(newWord);
                         }
                     }
-                    words_chars[j] = original_chars;
+                    wordsChars[j] = originalChars;
                 }
             }
             level++;
diff --git a/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java b/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
index 1af529f89459..2dfcf3909b8f 100644
--- a/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
+++ b/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
@@ -13,20 +13,20 @@ public static String encode(String s, int numRows) {
         char[] zigZagedArray = new char[s.length()];
         while (depth != 0) {
             int pointer = start;
-            int height_space = 2 + ((height - 2) * 2);
-            int depth_space = 2 + ((depth - 2) * 2);
+            int heightSpace = 2 + ((height - 2) * 2);
+            int depthSpace = 2 + ((depth - 2) * 2);
             boolean bool = true;
             while (pointer < s.length()) {
                 zigZagedArray[index++] = s.charAt(pointer);
-                if (height_space == 0)
-                    pointer += depth_space;
-                else if (depth_space == 0)
-                    pointer += height_space;
+                if (heightSpace == 0)
+                    pointer += depthSpace;
+                else if (depthSpace == 0)
+                    pointer += heightSpace;
                 else if (bool) {
-                    pointer += depth_space;
+                    pointer += depthSpace;
                     bool = false;
                 } else {
-                    pointer += height_space;
+                    pointer += heightSpace;
                     bool = true;
                 }
             }
diff --git a/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java b/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
index ada3c23f4c65..17a1d2374d66 100644
--- a/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
+++ b/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
@@ -13,28 +13,29 @@ class StrassenMatrixMultiplicationTest {
 
     @Test
     public void strassenMatrixMultiplicationTest2x2() {
-        int[][] A = {{1, 2}, {3, 4}};
-        int[][] B = {{5, 6}, {7, 8}};
+        int[][] a = {{1, 2}, {3, 4}};
+        int[][] b = {{5, 6}, {7, 8}};
         int[][] expResult = {{19, 22}, {43, 50}};
-        int[][] actResult = SMM.multiply(A, B);
+        int[][] actResult = SMM.multiply(a, b);
         assertArrayEquals(expResult, actResult);
     }
 
     @Test
     void strassenMatrixMultiplicationTest4x4() {
-        int[][] A = {{1, 2, 5, 4}, {9, 3, 0, 6}, {4, 6, 3, 1}, {0, 2, 0, 6}};
-        int[][] B = {{1, 0, 4, 1}, {1, 2, 0, 2}, {0, 3, 1, 3}, {1, 8, 1, 2}};
+        int[][] a = {{1, 2, 5, 4}, {9, 3, 0, 6}, {4, 6, 3, 1}, {0, 2, 0, 6}};
+        int[][] b = {{1, 0, 4, 1}, {1, 2, 0, 2}, {0, 3, 1, 3}, {1, 8, 1, 2}};
         int[][] expResult = {{7, 51, 13, 28}, {18, 54, 42, 27}, {11, 29, 20, 27}, {8, 52, 6, 16}};
-        int[][] actResult = SMM.multiply(A, B);
+        int[][] actResult = SMM.multiply(a, b);
         assertArrayEquals(expResult, actResult);
     }
 
     @Test
-    void strassenMatrixMultiplicationTestNegativeNumber4x4() {
-        int[][] A = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};
-        int[][] B = {{1, -2, -3, 4}, {4, -3, -2, 1}, {5, -6, -7, 8}, {8, -7, -6, -5}};
+
+    void strassenMatrixMultiplicationTestNegetiveNumber4x4() {
+        int[][] a = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};
+        int[][] b = {{1, -2, -3, 4}, {4, -3, -2, 1}, {5, -6, -7, 8}, {8, -7, -6, -5}};
         int[][] expResult = {{56, -54, -52, 10}, {128, -126, -124, 42}, {200, -198, -196, 74}, {272, -270, -268, 106}};
-        int[][] actResult = SMM.multiply(A, B);
+        int[][] actResult = SMM.multiply(a, b);
         assertArrayEquals(expResult, actResult);
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java
index 72e1d660028c..173ed00488d0 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java
@@ -15,11 +15,11 @@ public void testOptimalJobScheduling1() {
         int numberProcesses = 5;
         int numberMachines = 4;
 
-        int[][] Run = {{5, 1, 3, 2}, {4, 2, 1, 3}, {1, 5, 2, 1}, {2, 3, 4, 2}, {1, 1, 3, 1}};
+        int[][] run = {{5, 1, 3, 2}, {4, 2, 1, 3}, {1, 5, 2, 1}, {2, 3, 4, 2}, {1, 1, 3, 1}};
 
-        int[][] Transfer = {{0, 1, 2, 4}, {1, 0, 2, 3}, {2, 2, 0, 1}, {4, 3, 1, 0}};
+        int[][] transfer = {{0, 1, 2, 4}, {1, 0, 2, 3}, {2, 2, 0, 1}, {4, 3, 1, 0}};
 
-        OptimalJobScheduling opt = new OptimalJobScheduling(numberProcesses, numberMachines, Run, Transfer);
+        OptimalJobScheduling opt = new OptimalJobScheduling(numberProcesses, numberMachines, run, transfer);
 
         opt.execute();
 
@@ -40,11 +40,11 @@ public void testOptimalJobScheduling2() {
         int numberProcesses = 3;
         int numberMachines = 3;
 
-        int[][] Run = {{5, 1, 3}, {4, 2, 1}, {1, 5, 2}};
+        int[][] run = {{5, 1, 3}, {4, 2, 1}, {1, 5, 2}};
 
-        int[][] Transfer = {{0, 1, 2}, {1, 0, 2}, {2, 2, 0}};
+        int[][] transfer = {{0, 1, 2}, {1, 0, 2}, {2, 2, 0}};
 
-        OptimalJobScheduling opt = new OptimalJobScheduling(numberProcesses, numberMachines, Run, Transfer);
+        OptimalJobScheduling opt = new OptimalJobScheduling(numberProcesses, numberMachines, run, transfer);
 
         opt.execute();
 
@@ -65,7 +65,7 @@ public void testOptimalJobScheduling3() {
         int numberProcesses = 6;
         int numberMachines = 4;
 
-        int[][] Run = {
+        int[][] run = {
             {5, 1, 3, 2},
             {4, 2, 1, 1},
             {1, 5, 2, 6},
@@ -74,14 +74,14 @@ public void testOptimalJobScheduling3() {
             {3, 2, 2, 3},
         };
 
-        int[][] Transfer = {
+        int[][] transfer = {
             {0, 1, 2, 1},
             {1, 0, 2, 3},
             {2, 2, 0, 2},
             {1, 3, 2, 0},
         };
 
-        OptimalJobScheduling opt = new OptimalJobScheduling(numberProcesses, numberMachines, Run, Transfer);
+        OptimalJobScheduling opt = new OptimalJobScheduling(numberProcesses, numberMachines, run, transfer);
 
         opt.execute();
 

From 1a98ebe36bac61c8edc5223533d320ac03f3bec9 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 28 May 2024 20:57:32 +0200
Subject: [PATCH 0179/1338] style: enable `MissingSwitchDefault` in CheckStyle
 (#5188)

---
 checkstyle.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 6357bcb4ddbd..8b659d986af8 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -166,7 +166,7 @@
     <module name="IllegalInstantiation"/>
     <module name="InnerAssignment"/>
     <!-- TODO <module name="MagicNumber"/> -->
-    <!-- TODO <module name="MissingSwitchDefault"/> -->
+    <module name="MissingSwitchDefault"/>
     <module name="MultipleVariableDeclarations"/>
     <module name="SimplifyBooleanExpression"/>
     <module name="SimplifyBooleanReturn"/>

From 2cda9446434dc6ec7c65d7aad66a2e72e0258cb5 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 28 May 2024 21:03:52 +0200
Subject: [PATCH 0180/1338] style: include `ENMI_EQUALS_ON_ENUM` (#5189)

---
 spotbugs-exclude.xml                                          | 3 ---
 .../com/thealgorithms/datastructures/crdt/LWWElementSet.java  | 4 ++--
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 99a24bbff9d5..45ea8ed05d07 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -222,9 +222,6 @@
     <Match>
         <Bug pattern="FCBL_FIELD_COULD_BE_LOCAL" />
     </Match>
-    <Match>
-        <Bug pattern="ENMI_EQUALS_ON_ENUM" />
-    </Match>
     <Match>
         <Bug pattern="IMC_IMMATURE_CLASS_VAR_NAME" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java b/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
index b8b296359844..2c6ce8a427d1 100644
--- a/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
@@ -124,14 +124,14 @@ public void merge(LWWElementSet other) {
      * @return True if the first element's timestamp is greater or the bias is ADDS and timestamps are equal.
      */
     public boolean compareTimestamps(Element e, Element other) {
-        if (!e.bias.equals(other.bias)) {
+        if (e.bias != other.bias) {
             throw new IllegalArgumentException("Invalid bias value");
         }
         Bias bias = e.bias;
         int timestampComparison = Integer.compare(e.timestamp, other.timestamp);
 
         if (timestampComparison == 0) {
-            return !bias.equals(Bias.ADDS);
+            return bias != Bias.ADDS;
         }
         return timestampComparison < 0;
     }

From d2bfb100b22a1b8ad86d99dfcc75a5f65db6e874 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 28 May 2024 21:06:47 +0200
Subject: [PATCH 0181/1338] style: include `LII_LIST_INDEXED_ITERATING` (#5190)

---
 spotbugs-exclude.xml                                          | 3 ---
 .../java/com/thealgorithms/scheduling/FCFSScheduling.java     | 4 ++--
 src/main/java/com/thealgorithms/scheduling/RRScheduling.java  | 4 +++-
 3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 45ea8ed05d07..02e03725c429 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -141,9 +141,6 @@
     <Match>
         <Bug pattern="TR_TAIL_RECURSION" />
     </Match>
-    <Match>
-        <Bug pattern="LII_LIST_INDEXED_ITERATING" />
-    </Match>
     <Match>
         <Bug pattern="USBR_UNNECESSARY_STORE_BEFORE_RETURN" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java b/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java
index e73937f60b48..b22e81fe560e 100644
--- a/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java
@@ -40,8 +40,8 @@ private void evaluateWaitingTime() {
     }
 
     private void evaluateTurnAroundTime() {
-        for (int i = 0; i < processes.size(); i++) {
-            processes.get(i).setTurnAroundTimeTime(processes.get(i).getBurstTime() + processes.get(i).getWaitingTime());
+        for (final var process : processes) {
+            process.setTurnAroundTimeTime(process.getBurstTime() + process.getWaitingTime());
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/scheduling/RRScheduling.java b/src/main/java/com/thealgorithms/scheduling/RRScheduling.java
index 9968f172b482..991c9a4f6148 100644
--- a/src/main/java/com/thealgorithms/scheduling/RRScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/RRScheduling.java
@@ -95,6 +95,8 @@ private void evaluateTurnAroundTime() {
     }
 
     private void evaluateWaitingTime() {
-        for (int i = 0; i < processes.size(); i++) processes.get(i).setWaitingTime(processes.get(i).getTurnAroundTimeTime() - processes.get(i).getBurstTime());
+        for (final var process : processes) {
+            process.setWaitingTime(process.getTurnAroundTimeTime() - process.getBurstTime());
+        }
     }
 }

From a6e873deefade4d302d12f4bc63a51ec10daf67c Mon Sep 17 00:00:00 2001
From: "S. Utkarsh" <69796213+cpu-pixel@users.noreply.github.com>
Date: Thu, 30 May 2024 02:14:14 +0530
Subject: [PATCH 0182/1338] style: enable `MemberName` in checkstyle (#5193)

* style: enable MemberName in checkstyle

* style: simply uncomment `MemberName`

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 checkstyle.xml                                |  2 +-
 .../com/thealgorithms/ciphers/Blowfish.java   | 20 ++--
 .../conversions/HexaDecimalToBinary.java      |  4 +-
 .../datastructures/crdt/GCounter.java         | 14 +--
 .../datastructures/crdt/PNCounter.java        | 26 +++---
 .../datastructures/graphs/FloydWarshall.java  | 12 +--
 .../graphs/HamiltonianCycle.java              | 12 +--
 .../datastructures/graphs/MatrixGraphs.java   | 36 ++++----
 .../graphs/TarjansAlgorithm.java              | 14 +--
 .../hashmap/hashing/HashMapCuckooHashing.java | 20 ++--
 .../queues/GenericArrayListQueue.java         | 10 +-
 .../datastructures/trees/FenwickTree.java     |  8 +-
 .../datastructures/trees/RedBlackBST.java     | 92 +++++++++----------
 .../datastructures/trees/SegmentTree.java     | 14 +--
 .../OptimalJobScheduling.java                 | 38 ++++----
 .../StrassenMatrixMultiplicationTest.java     |  8 +-
 .../sorts/BinaryInsertionSortTest.java        |  6 +-
 17 files changed, 168 insertions(+), 168 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 8b659d986af8..de7c70266bfb 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -111,7 +111,7 @@
     <module name="ConstantName"/>
     <module name="LocalFinalVariableName"/>
     <module name="LocalVariableName"/>
-    <!-- TODO <module name="MemberName"/> -->
+    <module name="MemberName"/>
     <module name="MethodName"/>
     <module name="PackageName"/>
     <!-- TODO <module name="ParameterName"/> -->
diff --git a/src/main/java/com/thealgorithms/ciphers/Blowfish.java b/src/main/java/com/thealgorithms/ciphers/Blowfish.java
index d0e947206e5f..a8fa6fc56088 100644
--- a/src/main/java/com/thealgorithms/ciphers/Blowfish.java
+++ b/src/main/java/com/thealgorithms/ciphers/Blowfish.java
@@ -11,7 +11,7 @@
 public class Blowfish {
 
     // Initializing substitution boxes
-    String[][] S = {
+    String[][] sBox = {
         {
             "d1310ba6",
             "98dfb5ac",
@@ -1047,7 +1047,7 @@ public class Blowfish {
     };
 
     // Initializing subkeys with digits of pi
-    String[] P = {
+    String[] subKeys = {
         "243f6a88",
         "85a308d3",
         "13198a2e",
@@ -1154,7 +1154,7 @@ private String f(String plainText) {
         for (int i = 0; i < 8; i += 2) {
             // column number for S-box is a 8-bit value
             long col = Long.parseUnsignedLong(hexToBin(plainText.substring(i, i + 2)), 2);
-            a[i / 2] = S[i / 2][(int) col];
+            a[i / 2] = sBox[i / 2][(int) col];
         }
         ans = addBin(a[0], a[1]);
         ans = xor(ans, a[2]);
@@ -1165,9 +1165,9 @@ private String f(String plainText) {
     // generate subkeys
     private void keyGenerate(String key) {
         int j = 0;
-        for (int i = 0; i < P.length; i++) {
+        for (int i = 0; i < subKeys.length; i++) {
             // XOR-ing 32-bit parts of the key with initial subkeys
-            P[i] = xor(P[i], key.substring(j, j + 8));
+            subKeys[i] = xor(subKeys[i], key.substring(j, j + 8));
 
             j = (j + 8) % key.length();
         }
@@ -1179,7 +1179,7 @@ private String round(int time, String plainText) {
         String right;
         left = plainText.substring(0, 8);
         right = plainText.substring(8, 16);
-        left = xor(left, P[time]);
+        left = xor(left, subKeys[time]);
 
         // output from F function
         String fOut = f(left);
@@ -1207,8 +1207,8 @@ String encrypt(String plainText, String key) {
         // postprocessing
         String right = plainText.substring(0, 8);
         String left = plainText.substring(8, 16);
-        right = xor(right, P[16]);
-        left = xor(left, P[17]);
+        right = xor(right, subKeys[16]);
+        left = xor(left, subKeys[17]);
         return left + right;
     }
 
@@ -1229,8 +1229,8 @@ String decrypt(String cipherText, String key) {
         // postprocessing
         String right = cipherText.substring(0, 8);
         String left = cipherText.substring(8, 16);
-        right = xor(right, P[1]);
-        left = xor(left, P[0]);
+        right = xor(right, subKeys[1]);
+        left = xor(left, subKeys[0]);
         return left + right;
     }
 }
diff --git a/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java b/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
index 5372c95f23d4..c766b83f1c7b 100644
--- a/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
+++ b/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
@@ -3,7 +3,7 @@
 // Hex [0-9],[A-F] -> Binary [0,1]
 public class HexaDecimalToBinary {
 
-    private final int LONG_BITS = 8;
+    private final int longBits = 8;
 
     public String convert(String numHex) {
         // String a HexaDecimal:
@@ -15,7 +15,7 @@ public String convert(String numHex) {
     }
 
     public String completeDigits(String binNum) {
-        for (int i = binNum.length(); i < LONG_BITS; i++) {
+        for (int i = binNum.length(); i < longBits; i++) {
             binNum = "0" + binNum;
         }
         return binNum;
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java b/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java
index ced55d87a3cf..25b01bce19f3 100644
--- a/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java
@@ -17,7 +17,7 @@
  */
 
 class GCounter {
-    private final Map<Integer, Integer> P;
+    private final Map<Integer, Integer> counterMap;
     private final int myId;
     private final int n;
 
@@ -29,10 +29,10 @@ class GCounter {
     GCounter(int myId, int n) {
         this.myId = myId;
         this.n = n;
-        this.P = new HashMap<>();
+        this.counterMap = new HashMap<>();
 
         for (int i = 0; i < n; i++) {
-            P.put(i, 0);
+            counterMap.put(i, 0);
         }
     }
 
@@ -40,7 +40,7 @@ class GCounter {
      * Increments the counter for the current node.
      */
     public void increment() {
-        P.put(myId, P.get(myId) + 1);
+        counterMap.put(myId, counterMap.get(myId) + 1);
     }
 
     /**
@@ -50,7 +50,7 @@ public void increment() {
      */
     public int value() {
         int sum = 0;
-        for (int v : P.values()) {
+        for (int v : counterMap.values()) {
             sum += v;
         }
         return sum;
@@ -64,7 +64,7 @@ public int value() {
      */
     public boolean compare(GCounter other) {
         for (int i = 0; i < n; i++) {
-            if (this.P.get(i) > other.P.get(i)) {
+            if (this.counterMap.get(i) > other.counterMap.get(i)) {
                 return false;
             }
         }
@@ -78,7 +78,7 @@ public boolean compare(GCounter other) {
      */
     public void merge(GCounter other) {
         for (int i = 0; i < n; i++) {
-            this.P.put(i, Math.max(this.P.get(i), other.P.get(i)));
+            this.counterMap.put(i, Math.max(this.counterMap.get(i), other.counterMap.get(i)));
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java b/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java
index 04b846758f37..53c21dcbd108 100644
--- a/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java
@@ -17,8 +17,8 @@
  */
 
 class PNCounter {
-    private final Map<Integer, Integer> P;
-    private final Map<Integer, Integer> N;
+    private final Map<Integer, Integer> pCounter;
+    private final Map<Integer, Integer> nCounter;
     private final int myId;
     private final int n;
 
@@ -31,12 +31,12 @@ class PNCounter {
     PNCounter(int myId, int n) {
         this.myId = myId;
         this.n = n;
-        this.P = new HashMap<>();
-        this.N = new HashMap<>();
+        this.pCounter = new HashMap<>();
+        this.nCounter = new HashMap<>();
 
         for (int i = 0; i < n; i++) {
-            P.put(i, 0);
-            N.put(i, 0);
+            pCounter.put(i, 0);
+            nCounter.put(i, 0);
         }
     }
 
@@ -44,14 +44,14 @@ class PNCounter {
      * Increments the increment counter for the current node.
      */
     public void increment() {
-        P.put(myId, P.get(myId) + 1);
+        pCounter.put(myId, pCounter.get(myId) + 1);
     }
 
     /**
      * Increments the decrement counter for the current node.
      */
     public void decrement() {
-        N.put(myId, N.get(myId) + 1);
+        nCounter.put(myId, nCounter.get(myId) + 1);
     }
 
     /**
@@ -60,8 +60,8 @@ public void decrement() {
      * @return The total value of the counter.
      */
     public int value() {
-        int sumP = P.values().stream().mapToInt(Integer::intValue).sum();
-        int sumN = N.values().stream().mapToInt(Integer::intValue).sum();
+        int sumP = pCounter.values().stream().mapToInt(Integer::intValue).sum();
+        int sumN = nCounter.values().stream().mapToInt(Integer::intValue).sum();
         return sumP - sumN;
     }
 
@@ -76,7 +76,7 @@ public boolean compare(PNCounter other) {
             throw new IllegalArgumentException("Cannot compare PN-Counters with different number of nodes");
         }
         for (int i = 0; i < n; i++) {
-            if (this.P.get(i) > other.P.get(i) && this.N.get(i) > other.N.get(i)) {
+            if (this.pCounter.get(i) > other.pCounter.get(i) && this.nCounter.get(i) > other.nCounter.get(i)) {
                 return false;
             }
         }
@@ -93,8 +93,8 @@ public void merge(PNCounter other) {
             throw new IllegalArgumentException("Cannot merge PN-Counters with different number of nodes");
         }
         for (int i = 0; i < n; i++) {
-            this.P.put(i, Math.max(this.P.get(i), other.P.get(i)));
-            this.N.put(i, Math.max(this.N.get(i), other.N.get(i)));
+            this.pCounter.put(i, Math.max(this.pCounter.get(i), other.pCounter.get(i)));
+            this.nCounter.put(i, Math.max(this.nCounter.get(i), other.nCounter.get(i)));
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java b/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
index b295fb08c1dc..a574b40daec6 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
@@ -4,12 +4,12 @@
 
 public class FloydWarshall {
 
-    private int[][] DistanceMatrix;
+    private int[][] distanceMatrix;
     private int numberofvertices; // number of vertices in the graph
     public static final int INFINITY = 999;
 
     public FloydWarshall(int numberofvertices) {
-        DistanceMatrix = new int[numberofvertices + 1][numberofvertices + 1]; // stores the value of distance from all the possible path form the source
+        distanceMatrix = new int[numberofvertices + 1][numberofvertices + 1]; // stores the value of distance from all the possible path form the source
         // vertex to destination vertex
         // The matrix is initialized with 0's by default
         this.numberofvertices = numberofvertices;
@@ -18,17 +18,17 @@ public FloydWarshall(int numberofvertices) {
     public void floydwarshall(int[][] AdjacencyMatrix) { // calculates all the distances from source to destination vertex
         for (int source = 1; source <= numberofvertices; source++) {
             for (int destination = 1; destination <= numberofvertices; destination++) {
-                DistanceMatrix[source][destination] = AdjacencyMatrix[source][destination];
+                distanceMatrix[source][destination] = AdjacencyMatrix[source][destination];
             }
         }
         for (int intermediate = 1; intermediate <= numberofvertices; intermediate++) {
             for (int source = 1; source <= numberofvertices; source++) {
                 for (int destination = 1; destination <= numberofvertices; destination++) {
-                    if (DistanceMatrix[source][intermediate] + DistanceMatrix[intermediate][destination] < DistanceMatrix[source][destination]) { // calculated distance it get replaced as
+                    if (distanceMatrix[source][intermediate] + distanceMatrix[intermediate][destination] < distanceMatrix[source][destination]) { // calculated distance it get replaced as
                                                                                                                                                   // new shortest distance // if the new
                                                                                                                                                   // distance calculated is less then the
                                                                                                                                                   // earlier shortest
-                        DistanceMatrix[source][destination] = DistanceMatrix[source][intermediate] + DistanceMatrix[intermediate][destination];
+                        distanceMatrix[source][destination] = distanceMatrix[source][intermediate] + distanceMatrix[intermediate][destination];
                     }
                 }
             }
@@ -40,7 +40,7 @@ public void floydwarshall(int[][] AdjacencyMatrix) { // calculates all the dista
         for (int source = 1; source <= numberofvertices; source++) {
             System.out.print(source + "\t");
             for (int destination = 1; destination <= numberofvertices; destination++) {
-                System.out.print(DistanceMatrix[source][destination] + "\t");
+                System.out.print(distanceMatrix[source][destination] + "\t");
             }
             System.out.println();
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java b/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
index d12f631db6f1..65483eeeb65c 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
@@ -8,7 +8,7 @@
  */
 public class HamiltonianCycle {
 
-    private int V;
+    private int vertex;
     private int pathCount;
     private int[] cycle;
     private int[][] graph;
@@ -22,8 +22,8 @@ public class HamiltonianCycle {
      *         else returns 1D array with value -1.
      */
     public int[] findHamiltonianCycle(int[][] graph) {
-        this.V = graph.length;
-        this.cycle = new int[this.V + 1];
+        this.vertex = graph.length;
+        this.cycle = new int[this.vertex + 1];
 
         // Initialize path array with -1 value
         for (int i = 0; i < this.cycle.length; i++) {
@@ -53,17 +53,17 @@ public int[] findHamiltonianCycle(int[][] graph) {
      * @returns true if path is found false otherwise
      */
     public boolean isPathFound(int vertex) {
-        boolean isLastVertexConnectedToStart = this.graph[vertex][0] == 1 && this.pathCount == this.V;
+        boolean isLastVertexConnectedToStart = this.graph[vertex][0] == 1 && this.pathCount == this.vertex;
         if (isLastVertexConnectedToStart) {
             return true;
         }
 
         /** all vertices selected but last vertex not linked to 0 **/
-        if (this.pathCount == this.V) {
+        if (this.pathCount == this.vertex) {
             return false;
         }
 
-        for (int v = 0; v < this.V; v++) {
+        for (int v = 0; v < this.vertex; v++) {
             /** if connected **/
             if (this.graph[vertex][v] == 1) {
                 /** add to path **/
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java b/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
index c578053477d7..902553f9a54c 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
@@ -48,17 +48,17 @@ class AdjacencyMatrixGraph {
     /**
      * The number of vertices in the graph
      */
-    private int _numberOfVertices;
+    private int vertexCount;
 
     /**
      * The number of edges in the graph
      */
-    private int _numberOfEdges;
+    private int edgeCount;
 
     /**
      * The adjacency matrix for the graph
      */
-    private int[][] _adjacency;
+    private int[][] adjMatrix;
 
     /**
      * Static variables to define whether or not an edge exists in the adjacency
@@ -87,16 +87,16 @@ class AdjacencyMatrixGraph {
      * @param newNumberOfVertices the new number of vertices
      */
     private void setNumberOfVertices(int newNumberOfVertices) {
-        this._numberOfVertices = newNumberOfVertices;
+        this.vertexCount = newNumberOfVertices;
     }
 
     /**
-     * Getter for `this._numberOfVertices`
+     * Getter for `this.vertexCount`
      *
      * @return the number of vertices in the graph
      */
     public int numberOfVertices() {
-        return this._numberOfVertices;
+        return this.vertexCount;
     }
 
     /**
@@ -106,16 +106,16 @@ public int numberOfVertices() {
      *
      */
     private void setNumberOfEdges(int newNumberOfEdges) {
-        this._numberOfEdges = newNumberOfEdges;
+        this.edgeCount = newNumberOfEdges;
     }
 
     /**
-     * Getter for `this._numberOfEdges`
+     * Getter for `this.edgeCount`
      *
      * @return the number of edges
      */
     public int numberOfEdges() {
-        return this._numberOfEdges;
+        return this.edgeCount;
     }
 
     /**
@@ -124,7 +124,7 @@ public int numberOfEdges() {
      * @param newAdjacency the new adjaceny matrix
      */
     private void setAdjacency(int[][] newAdjacency) {
-        this._adjacency = newAdjacency;
+        this.adjMatrix = newAdjacency;
     }
 
     /**
@@ -133,7 +133,7 @@ private void setAdjacency(int[][] newAdjacency) {
      * @return the adjacency matrix
      */
     private int[][] adjacency() {
-        return this._adjacency;
+        return this.adjMatrix;
     }
 
     /**
@@ -222,12 +222,12 @@ public boolean removeEdge(int from, int to) {
      */
     public List<Integer> depthFirstOrder(int startVertex) {
         // If the startVertex is invalid, return an empty list
-        if (startVertex >= _numberOfVertices || startVertex < 0) {
+        if (startVertex >= vertexCount || startVertex < 0) {
             return new ArrayList<Integer>();
         }
 
         // Create an array to track the visited vertices
-        boolean[] visited = new boolean[_numberOfVertices];
+        boolean[] visited = new boolean[vertexCount];
 
         // Create a list to keep track of the order of our traversal
         ArrayList<Integer> orderList = new ArrayList<Integer>();
@@ -259,7 +259,7 @@ private void depthFirstOrder(int currentVertex, boolean[] visited, List<Integer>
         orderList.add(currentVertex);
 
         // Get the adjacency array for this vertex
-        int[] adjacent = _adjacency[currentVertex];
+        int[] adjacent = adjMatrix[currentVertex];
         for (int i = 0; i < adjacent.length; i++) { // we are considering exploring, recurse on it // If an edge exists between the
                                                     // currentVertex and the vertex
             if (adjacent[i] == AdjacencyMatrixGraph.EDGE_EXIST) {
@@ -277,12 +277,12 @@ private void depthFirstOrder(int currentVertex, boolean[] visited, List<Integer>
      */
     public List<Integer> breadthFirstOrder(int startVertex) {
         // If the specified startVertex is invalid, return an empty list
-        if (startVertex >= _numberOfVertices || startVertex < 0) {
+        if (startVertex >= vertexCount || startVertex < 0) {
             return new ArrayList<Integer>();
         }
 
         // Create an array to keep track of the visited vertices
-        boolean[] visited = new boolean[_numberOfVertices];
+        boolean[] visited = new boolean[vertexCount];
 
         // Create a list to keep track of the ordered vertices
         ArrayList<Integer> orderList = new ArrayList<Integer>();
@@ -309,7 +309,7 @@ public List<Integer> breadthFirstOrder(int startVertex) {
 
             // Get the adjacency array for the currentVertex and
             // check each node
-            int[] adjacent = _adjacency[currentVertex];
+            int[] adjacent = adjMatrix[currentVertex];
             for (int vertex = 0; vertex < adjacent.length; vertex++) { // vertex we are considering exploring, we add it to the queue // If an
                                                                        // edge exists between the current vertex and the
                 if (adjacent[vertex] == AdjacencyMatrixGraph.EDGE_EXIST) {
@@ -336,7 +336,7 @@ public String toString() {
         for (int i = 0; i < this.numberOfVertices(); i++) {
             s = s + i + " : ";
             for (int j = 0; j < this.numberOfVertices(); j++) {
-                s = s + this._adjacency[i][j] + " ";
+                s = s + this.adjMatrix[i][j] + " ";
             }
             s = s + "\n";
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
index 293ea5837823..251c169d11ac 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
@@ -56,9 +56,9 @@
 public class TarjansAlgorithm {
 
     // Timer for tracking lowtime and insertion time
-    private int Time;
+    private int time;
 
-    private List<List<Integer>> SCClist = new ArrayList<List<Integer>>();
+    private List<List<Integer>> sccList = new ArrayList<List<Integer>>();
 
     public List<List<Integer>> stronglyConnectedComponents(int V, List<List<Integer>> graph) {
 
@@ -85,15 +85,15 @@ public List<List<Integer>> stronglyConnectedComponents(int V, List<List<Integer>
             if (insertionTime[i] == -1) stronglyConnCompsUtil(i, lowTime, insertionTime, isInStack, st, graph);
         }
 
-        return SCClist;
+        return sccList;
     }
 
     private void stronglyConnCompsUtil(int u, int[] lowTime, int[] insertionTime, boolean[] isInStack, Stack<Integer> st, List<List<Integer>> graph) {
 
         // Initialize insertion time and lowTime value of current node
-        insertionTime[u] = Time;
-        lowTime[u] = Time;
-        Time += 1;
+        insertionTime[u] = time;
+        lowTime[u] = time;
+        time += 1;
 
         // Push current node into stack
         isInStack[u] = true;
@@ -123,7 +123,7 @@ private void stronglyConnCompsUtil(int u, int[] lowTime, int[] insertionTime, bo
                 scc.add(w);
                 isInStack[w] = false;
             }
-            SCClist.add(scc);
+            sccList.add(scc);
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
index 6f382766b3b1..b48502b51d08 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
@@ -12,21 +12,21 @@ public class HashMapCuckooHashing {
 
     private int tableSize; // size of the hash table
     private Integer[] buckets; // array representing the table
-    private final Integer AVAILABLE;
+    private final Integer emptySlot;
     private int size; // number of elements in the hash table
 
     private int thresh; // threshold for infinite loop checking
 
     /**
      * Constructor initializes buckets array, hsize, and creates dummy object
-     * for AVAILABLE
+     * for emptySlot
      *
      * @param tableSize the desired size of the hash map
      */
     public HashMapCuckooHashing(int tableSize) {
         this.buckets = new Integer[tableSize];
         this.tableSize = tableSize;
-        this.AVAILABLE = Integer.MIN_VALUE;
+        this.emptySlot = Integer.MIN_VALUE;
         this.size = 0;
         this.thresh = (int) (Math.log(tableSize) / Math.log(2)) + 2;
     }
@@ -84,7 +84,7 @@ public void insertKey2HashTable(int key) {
             loopCounter++;
             hash = hashFunction1(key);
 
-            if ((buckets[hash] == null) || Objects.equals(buckets[hash], AVAILABLE)) {
+            if ((buckets[hash] == null) || Objects.equals(buckets[hash], emptySlot)) {
                 buckets[hash] = wrappedInt;
                 size++;
                 checkLoadFactor();
@@ -95,7 +95,7 @@ public void insertKey2HashTable(int key) {
             buckets[hash] = wrappedInt;
             wrappedInt = temp;
             hash = hashFunction2(temp);
-            if (Objects.equals(buckets[hash], AVAILABLE)) {
+            if (Objects.equals(buckets[hash], emptySlot)) {
                 buckets[hash] = wrappedInt;
                 size++;
                 checkLoadFactor();
@@ -124,7 +124,7 @@ public void insertKey2HashTable(int key) {
     public void reHashTableIncreasesTableSize() {
         HashMapCuckooHashing newT = new HashMapCuckooHashing(tableSize * 2);
         for (int i = 0; i < tableSize; i++) {
-            if (buckets[i] != null && !Objects.equals(buckets[i], AVAILABLE)) {
+            if (buckets[i] != null && !Objects.equals(buckets[i], emptySlot)) {
                 newT.insertKey2HashTable(this.buckets[i]);
             }
         }
@@ -146,14 +146,14 @@ public void deleteKeyFromHashTable(int key) {
         }
 
         if (Objects.equals(buckets[hash], wrappedInt)) {
-            buckets[hash] = AVAILABLE;
+            buckets[hash] = emptySlot;
             size--;
             return;
         }
 
         hash = hashFunction2(key);
         if (Objects.equals(buckets[hash], wrappedInt)) {
-            buckets[hash] = AVAILABLE;
+            buckets[hash] = emptySlot;
             size--;
             return;
         }
@@ -165,7 +165,7 @@ public void deleteKeyFromHashTable(int key) {
      */
     public void displayHashtable() {
         for (int i = 0; i < tableSize; i++) {
-            if ((buckets[i] == null) || Objects.equals(buckets[i], AVAILABLE)) {
+            if ((buckets[i] == null) || Objects.equals(buckets[i], emptySlot)) {
                 System.out.println("Bucket " + i + ": Empty");
             } else {
                 System.out.println("Bucket " + i + ": " + buckets[i].toString());
@@ -229,7 +229,7 @@ public double checkLoadFactor() {
     public boolean isFull() {
         boolean response = true;
         for (int i = 0; i < tableSize; i++) {
-            if (buckets[i] == null || Objects.equals(buckets[i], AVAILABLE)) {
+            if (buckets[i] == null || Objects.equals(buckets[i], emptySlot)) {
                 return false;
             }
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java
index b9331569e131..ec1e15e415b8 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java
@@ -15,7 +15,7 @@ public class GenericArrayListQueue<T> {
     /**
      * The generic ArrayList for the queue T is the generic element
      */
-    ArrayList<T> _queue = new ArrayList<>();
+    ArrayList<T> elementList = new ArrayList<>();
 
     /**
      * Checks if the queue has elements (not empty).
@@ -23,7 +23,7 @@ public class GenericArrayListQueue<T> {
      * @return True if the queue has elements. False otherwise.
      */
     private boolean hasElements() {
-        return !_queue.isEmpty();
+        return !elementList.isEmpty();
     }
 
     /**
@@ -35,7 +35,7 @@ private boolean hasElements() {
     public T peek() {
         T result = null;
         if (this.hasElements()) {
-            result = _queue.get(0);
+            result = elementList.get(0);
         }
         return result;
     }
@@ -47,7 +47,7 @@ public T peek() {
      * @return True if the element was added successfully
      */
     public boolean add(T element) {
-        return _queue.add(element);
+        return elementList.add(element);
     }
 
     /**
@@ -58,7 +58,7 @@ public boolean add(T element) {
     public T pull() {
         T result = null;
         if (this.hasElements()) {
-            result = _queue.remove(0);
+            result = elementList.remove(0);
         }
         return result;
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java b/src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java
index 5cd28202229e..5378a01f6642 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java
@@ -3,12 +3,12 @@
 public class FenwickTree {
 
     private int n;
-    private int[] fen_t;
+    private int[] fenTree;
 
     /* Constructor which takes the size of the array as a parameter */
     public FenwickTree(int n) {
         this.n = n;
-        this.fen_t = new int[n + 1];
+        this.fenTree = new int[n + 1];
     }
 
     /* A function which will add the element val at index i*/
@@ -16,7 +16,7 @@ public void update(int i, int val) {
         // As index starts from 0, increment the index by 1
         i += 1;
         while (i <= n) {
-            fen_t[i] += val;
+            fenTree[i] += val;
             i += i & (-i);
         }
     }
@@ -27,7 +27,7 @@ public int query(int i) {
         i += 1;
         int cumSum = 0;
         while (i > 0) {
-            cumSum += fen_t[i];
+            cumSum += fenTree[i];
             i -= i & (-i);
         }
         return cumSum;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java b/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
index c7cb108d6b77..2961282efe75 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
@@ -7,13 +7,13 @@
  */
 public class RedBlackBST {
 
-    private final int R = 0;
-    private final int B = 1;
+    private final int red = 0;
+    private final int black = 1;
 
     private class Node {
 
         int key = -1;
-        int color = B;
+        int color = black;
         Node left = nil;
         Node right = nil;
         Node p = nil;
@@ -31,7 +31,7 @@ public void printTree(Node node) {
             return;
         }
         printTree(node.left);
-        System.out.print(((node.color == R) ? " R " : " B ") + "Key: " + node.key + " Parent: " + node.p.key + "\n");
+        System.out.print(((node.color == red) ? " R " : " B ") + "Key: " + node.key + " Parent: " + node.p.key + "\n");
         printTree(node.right);
     }
 
@@ -39,7 +39,7 @@ public void printTreepre(Node node) {
         if (node == nil) {
             return;
         }
-        System.out.print(((node.color == R) ? " R " : " B ") + "Key: " + node.key + " Parent: " + node.p.key + "\n");
+        System.out.print(((node.color == red) ? " R " : " B ") + "Key: " + node.key + " Parent: " + node.p.key + "\n");
         printTreepre(node.left);
         printTreepre(node.right);
     }
@@ -66,10 +66,10 @@ private void insert(Node node) {
         Node temp = root;
         if (root == nil) {
             root = node;
-            node.color = B;
+            node.color = black;
             node.p = nil;
         } else {
-            node.color = R;
+            node.color = red;
             while (true) {
                 if (node.key < temp.key) {
                     if (temp.left == nil) {
@@ -94,15 +94,15 @@ private void insert(Node node) {
     }
 
     private void fixTree(Node node) {
-        while (node.p.color == R) {
+        while (node.p.color == red) {
             Node y = nil;
             if (node.p == node.p.p.left) {
                 y = node.p.p.right;
 
-                if (y != nil && y.color == R) {
-                    node.p.color = B;
-                    y.color = B;
-                    node.p.p.color = R;
+                if (y != nil && y.color == red) {
+                    node.p.color = black;
+                    y.color = black;
+                    node.p.p.color = red;
                     node = node.p.p;
                     continue;
                 }
@@ -110,15 +110,15 @@ private void fixTree(Node node) {
                     node = node.p;
                     rotateLeft(node);
                 }
-                node.p.color = B;
-                node.p.p.color = R;
+                node.p.color = black;
+                node.p.p.color = red;
                 rotateRight(node.p.p);
             } else {
                 y = node.p.p.left;
-                if (y != nil && y.color == R) {
-                    node.p.color = B;
-                    y.color = B;
-                    node.p.p.color = R;
+                if (y != nil && y.color == red) {
+                    node.p.color = black;
+                    y.color = black;
+                    node.p.p.color = red;
                     node = node.p.p;
                     continue;
                 }
@@ -126,12 +126,12 @@ private void fixTree(Node node) {
                     node = node.p;
                     rotateRight(node);
                 }
-                node.p.color = B;
-                node.p.p.color = R;
+                node.p.color = black;
+                node.p.p.color = red;
                 rotateLeft(node.p.p);
             }
         }
-        root.color = B;
+        root.color = black;
     }
 
     void rotateLeft(Node node) {
@@ -234,67 +234,67 @@ boolean delete(Node z) {
             y.left.p = y;
             y.color = z.color;
         }
-        if (yorigcolor == B) {
+        if (yorigcolor == black) {
             deleteFixup(x);
         }
         return true;
     }
 
     void deleteFixup(Node x) {
-        while (x != root && x.color == B) {
+        while (x != root && x.color == black) {
             if (x == x.p.left) {
                 Node w = x.p.right;
-                if (w.color == R) {
-                    w.color = B;
-                    x.p.color = R;
+                if (w.color == red) {
+                    w.color = black;
+                    x.p.color = red;
                     rotateLeft(x.p);
                     w = x.p.right;
                 }
-                if (w.left.color == B && w.right.color == B) {
-                    w.color = R;
+                if (w.left.color == black && w.right.color == black) {
+                    w.color = red;
                     x = x.p;
                     continue;
-                } else if (w.right.color == B) {
-                    w.left.color = B;
-                    w.color = R;
+                } else if (w.right.color == black) {
+                    w.left.color = black;
+                    w.color = red;
                     rotateRight(w);
                     w = x.p.right;
                 }
-                if (w.right.color == R) {
+                if (w.right.color == red) {
                     w.color = x.p.color;
-                    x.p.color = B;
-                    w.right.color = B;
+                    x.p.color = black;
+                    w.right.color = black;
                     rotateLeft(x.p);
                     x = root;
                 }
             } else {
                 Node w = x.p.left;
-                if (w.color == R) {
-                    w.color = B;
-                    x.p.color = R;
+                if (w.color == red) {
+                    w.color = black;
+                    x.p.color = red;
                     rotateRight(x.p);
                     w = x.p.left;
                 }
-                if (w.right.color == B && w.left.color == B) {
-                    w.color = R;
+                if (w.right.color == black && w.left.color == black) {
+                    w.color = red;
                     x = x.p;
                     continue;
-                } else if (w.left.color == B) {
-                    w.right.color = B;
-                    w.color = R;
+                } else if (w.left.color == black) {
+                    w.right.color = black;
+                    w.color = red;
                     rotateLeft(w);
                     w = x.p.left;
                 }
-                if (w.left.color == R) {
+                if (w.left.color == red) {
                     w.color = x.p.color;
-                    x.p.color = B;
-                    w.left.color = B;
+                    x.p.color = black;
+                    w.left.color = black;
                     rotateRight(x.p);
                     x = root;
                 }
             }
         }
-        x.color = B;
+        x.color = black;
     }
 
     public void insertDemo() {
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
index a6954b24cf3a..a6a76f8f094f 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
@@ -2,7 +2,7 @@
 
 public class SegmentTree {
 
-    private int[] seg_t;
+    private int[] segTree;
     private int n;
     private int[] arr;
 
@@ -12,7 +12,7 @@ public SegmentTree(int n, int[] arr) {
         int x = (int) (Math.ceil(Math.log(n) / Math.log(2)));
         int segSize = 2 * (int) Math.pow(2, x) - 1;
 
-        this.seg_t = new int[segSize];
+        this.segTree = new int[segSize];
         this.arr = arr;
         this.n = n;
         constructTree(arr, 0, n - 1, 0);
@@ -21,13 +21,13 @@ public SegmentTree(int n, int[] arr) {
     /* A function which will create the segment tree*/
     public final int constructTree(int[] arr, int start, int end, int index) {
         if (start == end) {
-            this.seg_t[index] = arr[start];
+            this.segTree[index] = arr[start];
             return arr[start];
         }
 
         int mid = start + (end - start) / 2;
-        this.seg_t[index] = constructTree(arr, start, mid, index * 2 + 1) + constructTree(arr, mid + 1, end, index * 2 + 2);
-        return this.seg_t[index];
+        this.segTree[index] = constructTree(arr, start, mid, index * 2 + 1) + constructTree(arr, mid + 1, end, index * 2 + 2);
+        return this.segTree[index];
     }
 
     /* A function which will update the value at a index i. This will be called by the
@@ -37,7 +37,7 @@ private void updateTree(int start, int end, int index, int diff, int seg_index)
             return;
         }
 
-        this.seg_t[seg_index] += diff;
+        this.segTree[seg_index] += diff;
         if (start != end) {
             int mid = start + (end - start) / 2;
             updateTree(start, mid, index, diff, seg_index * 2 + 1);
@@ -60,7 +60,7 @@ public void update(int index, int value) {
      * internally*/
     private int getSumTree(int start, int end, int q_start, int q_end, int seg_index) {
         if (q_start <= start && q_end >= end) {
-            return this.seg_t[seg_index];
+            return this.segTree[seg_index];
         }
 
         if (q_start > end || q_end < start) {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java b/src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java
index 5ee3327553d7..0840e08c531c 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java
@@ -13,24 +13,24 @@ public class OptimalJobScheduling {
 
     private final int numberProcesses;
     private final int numberMachines;
-    private final int[][] Run;
-    private final int[][] Transfer;
-    private final int[][] Cost;
+    private final int[][] run;
+    private final int[][] transfer;
+    private final int[][] cost;
 
     /**
      * Constructor of the class.
      * @param numberProcesses ,refers to the number of precedent processes(N)
      * @param numberMachines ,refers to the number of different machines in our disposal(M)
-     * @param Run , N*M matrix refers to the cost of running each process to each machine
-     * @param Transfer ,M*M symmetric matrix refers to the transportation delay for each pair of
+     * @param run , N*M matrix refers to the cost of running each process to each machine
+     * @param transfer ,M*M symmetric matrix refers to the transportation delay for each pair of
      *     machines
      */
-    public OptimalJobScheduling(int numberProcesses, int numberMachines, int[][] Run, int[][] Transfer) {
+    public OptimalJobScheduling(int numberProcesses, int numberMachines, int[][] run, int[][] transfer) {
         this.numberProcesses = numberProcesses;
         this.numberMachines = numberMachines;
-        this.Run = Run;
-        this.Transfer = Transfer;
-        this.Cost = new int[numberProcesses][numberMachines];
+        this.run = run;
+        this.transfer = transfer;
+        this.cost = new int[numberProcesses][numberMachines];
     }
 
     /**
@@ -50,7 +50,7 @@ private void calculateCost() {
 
             for (int j = 0; j < numberMachines; j++) { // for each Machine
 
-                Cost[i][j] = runningCost(i, j);
+                cost[i][j] = runningCost(i, j);
             }
         }
     }
@@ -71,7 +71,7 @@ private int runningCost(int process, int machine) {
 
         if (process == 0) // refers to the first process,which does not require for a previous one
                           // to have been executed
-            return Run[process][machine];
+            return run[process][machine];
         else {
 
             int[] runningCosts = new int[numberMachines]; // stores the costs of executing our Process depending on
@@ -79,7 +79,7 @@ private int runningCost(int process, int machine) {
 
             for (int k = 0; k < numberMachines; k++) // computes the cost of executing the previous
                                                      // process to each and every Machine
-                runningCosts[k] = Cost[process - 1][k] + Transfer[k][machine] + Run[process][machine]; // transferring the result to our Machine and executing
+                runningCosts[k] = cost[process - 1][k] + transfer[k][machine] + run[process][machine]; // transferring the result to our Machine and executing
                                                                                                        // the Process to our Machine
 
             return findMin(runningCosts); // returns the minimum running cost
@@ -88,19 +88,19 @@ private int runningCost(int process, int machine) {
 
     /**
      * Function used in order to return the minimum Cost.
-     * @param cost ,an Array of size M which refers to the costs of executing a Process to each
+     * @param costArr ,an Array of size M which refers to the costs of executing a Process to each
      *     Machine
      * @return the minimum cost
      */
-    private int findMin(int[] cost) {
+    private int findMin(int[] costArr) {
 
         int min = 0;
 
-        for (int i = 1; i < cost.length; i++) {
+        for (int i = 1; i < costArr.length; i++) {
 
-            if (cost[i] < cost[min]) min = i;
+            if (costArr[i] < costArr[min]) min = i;
         }
-        return cost[min];
+        return costArr[min];
     }
 
     /**
@@ -111,7 +111,7 @@ private void showResults() {
         for (int i = 0; i < numberProcesses; i++) {
 
             for (int j = 0; j < numberMachines; j++) {
-                System.out.print(Cost[i][j]);
+                System.out.print(cost[i][j]);
                 System.out.print(" ");
             }
 
@@ -124,6 +124,6 @@ private void showResults() {
      * Getter for the running Cost of i process on j machine.
      */
     public int getCost(int process, int machine) {
-        return Cost[process][machine];
+        return cost[process][machine];
     }
 }
diff --git a/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java b/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
index 17a1d2374d66..1ec45a863e1a 100644
--- a/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
+++ b/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java
@@ -6,7 +6,7 @@
 
 class StrassenMatrixMultiplicationTest {
 
-    StrassenMatrixMultiplication SMM = new StrassenMatrixMultiplication();
+    StrassenMatrixMultiplication smm = new StrassenMatrixMultiplication();
 
     // Strassen Matrix Multiplication can only be allplied to matrices of size 2^n
     // and has to be a Square Matrix
@@ -16,7 +16,7 @@ public void strassenMatrixMultiplicationTest2x2() {
         int[][] a = {{1, 2}, {3, 4}};
         int[][] b = {{5, 6}, {7, 8}};
         int[][] expResult = {{19, 22}, {43, 50}};
-        int[][] actResult = SMM.multiply(a, b);
+        int[][] actResult = smm.multiply(a, b);
         assertArrayEquals(expResult, actResult);
     }
 
@@ -25,7 +25,7 @@ void strassenMatrixMultiplicationTest4x4() {
         int[][] a = {{1, 2, 5, 4}, {9, 3, 0, 6}, {4, 6, 3, 1}, {0, 2, 0, 6}};
         int[][] b = {{1, 0, 4, 1}, {1, 2, 0, 2}, {0, 3, 1, 3}, {1, 8, 1, 2}};
         int[][] expResult = {{7, 51, 13, 28}, {18, 54, 42, 27}, {11, 29, 20, 27}, {8, 52, 6, 16}};
-        int[][] actResult = SMM.multiply(a, b);
+        int[][] actResult = smm.multiply(a, b);
         assertArrayEquals(expResult, actResult);
     }
 
@@ -35,7 +35,7 @@ void strassenMatrixMultiplicationTestNegetiveNumber4x4() {
         int[][] a = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};
         int[][] b = {{1, -2, -3, 4}, {4, -3, -2, 1}, {5, -6, -7, 8}, {8, -7, -6, -5}};
         int[][] expResult = {{56, -54, -52, 10}, {128, -126, -124, 42}, {200, -198, -196, 74}, {272, -270, -268, 106}};
-        int[][] actResult = SMM.multiply(a, b);
+        int[][] actResult = smm.multiply(a, b);
         assertArrayEquals(expResult, actResult);
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java b/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
index 2c355cee01b8..bdd0702942a2 100644
--- a/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
@@ -6,14 +6,14 @@
 
 class BinaryInsertionSortTest {
 
-    BinaryInsertionSort BIS = new BinaryInsertionSort();
+    BinaryInsertionSort bis = new BinaryInsertionSort();
 
     @Test
     // valid test case
     public void binaryInsertionSortTestNonDuplicate() {
         int[] array = {1, 0, 2, 5, 3, 4, 9, 8, 10, 6, 7};
         int[] expResult = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
-        int[] actResult = BIS.binaryInsertSort(array);
+        int[] actResult = bis.binaryInsertSort(array);
         assertArrayEquals(expResult, actResult);
     }
 
@@ -21,7 +21,7 @@ public void binaryInsertionSortTestNonDuplicate() {
     public void binaryInsertionSortTestDuplicate() {
         int[] array = {1, 1, 1, 5, 9, 8, 7, 2, 6};
         int[] expResult = {1, 1, 1, 2, 5, 6, 7, 8, 9};
-        int[] actResult = BIS.binaryInsertSort(array);
+        int[] actResult = bis.binaryInsertSort(array);
         assertArrayEquals(expResult, actResult);
     }
 }

From 2568b96784e50ce517aa223e29302fc10ef3caac Mon Sep 17 00:00:00 2001
From: Alex K <alexanderklmn@gmail.com>
Date: Thu, 30 May 2024 21:43:15 +0300
Subject: [PATCH 0183/1338] Adding class for generating all subsequences from a
 given List (#5194)

* Adding class for generating all subsequences from a given List

* Fix test data format

* Fix braces wrong placement

* Fix "Utility classes should not have a public or default constructor."

* Fix checkstyle " Class Subsequence should be declared as final."

* Renaming class Subsequence to SubsequenceFinder. Refactored test to Parametrized test. Fixed input parameter as final.

* Fix formatting

* Fix formatting

* Fix formatting

* Fix import ordering

* Renaming method generate all.
Renaming test method.
Adding duplication test.
Renaming TestData to TestCase.

* Fix formatting

* style: add assertion to avoid potential infinite loop

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../backtracking/SubsequenceFinder.java       | 54 +++++++++++++++++++
 .../backtracking/SubsequenceFinderTest.java   | 28 ++++++++++
 2 files changed, 82 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/backtracking/SubsequenceFinder.java
 create mode 100644 src/test/java/com/thealgorithms/backtracking/SubsequenceFinderTest.java

diff --git a/src/main/java/com/thealgorithms/backtracking/SubsequenceFinder.java b/src/main/java/com/thealgorithms/backtracking/SubsequenceFinder.java
new file mode 100644
index 000000000000..4a159dbfe0b1
--- /dev/null
+++ b/src/main/java/com/thealgorithms/backtracking/SubsequenceFinder.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.backtracking;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Class generates all subsequences for a given list of elements using backtracking
+ */
+public final class SubsequenceFinder {
+    private SubsequenceFinder() {
+    }
+
+    /**
+     * Find all subsequences of given list using backtracking
+     *
+     * @param sequence a list of items on the basis of which we need to generate all subsequences
+     * @param <T> the type of elements in the array
+     * @return a list of all subsequences
+     */
+    public static <T> List<List<T>> generateAll(List<T> sequence) {
+        List<List<T>> allSubSequences = new ArrayList<>();
+        if (sequence.isEmpty()) {
+            allSubSequences.add(new ArrayList<>());
+            return allSubSequences;
+        }
+        List<T> currentSubsequence = new ArrayList<>();
+        backtrack(sequence, currentSubsequence, 0, allSubSequences);
+        return allSubSequences;
+    }
+
+    /**
+     * Iterate through each branch of states
+     * We know that each state has exactly two branching
+     * It terminates when it reaches the end of the given sequence
+     *
+     * @param sequence all elements
+     * @param currentSubsequence current subsequence
+     * @param index current index
+     * @param allSubSequences contains all sequences
+     * @param <T> the type of elements which we generate
+     */
+    private static <T> void backtrack(List<T> sequence, List<T> currentSubsequence, final int index, List<List<T>> allSubSequences) {
+        assert index <= sequence.size();
+        if (index == sequence.size()) {
+            allSubSequences.add(new ArrayList<>(currentSubsequence));
+            return;
+        }
+
+        backtrack(sequence, currentSubsequence, index + 1, allSubSequences);
+        currentSubsequence.add(sequence.get(index));
+        backtrack(sequence, currentSubsequence, index + 1, allSubSequences);
+        currentSubsequence.removeLast();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/backtracking/SubsequenceFinderTest.java b/src/test/java/com/thealgorithms/backtracking/SubsequenceFinderTest.java
new file mode 100644
index 000000000000..dac2e2675674
--- /dev/null
+++ b/src/test/java/com/thealgorithms/backtracking/SubsequenceFinderTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.backtracking;
+
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class SubsequenceFinderTest {
+
+    @ParameterizedTest
+    @MethodSource("getTestCases")
+    void testGenerateAll(TestCase testData) {
+        final var actual = SubsequenceFinder.generateAll(testData.input());
+        assertIterableEquals(testData.expected(), actual);
+    }
+
+    static Stream<TestCase> getTestCases() {
+        return Stream.of(new TestCase(new ArrayList<>(), List.of(List.of())), new TestCase(List.of(1, 2), List.of(List.of(), List.of(2), List.of(1), List.of(1, 2))),
+            new TestCase(List.of("A", "B", "C"), List.of(List.of(), List.of("C"), List.of("B"), List.of("B", "C"), List.of("A"), List.of("A", "C"), List.of("A", "B"), List.of("A", "B", "C"))),
+            new TestCase(List.of(1, 2, 3), List.of(List.of(), List.of(3), List.of(2), List.of(2, 3), List.of(1), List.of(1, 3), List.of(1, 2), List.of(1, 2, 3))), new TestCase(List.of(2, 2), List.of(List.of(), List.of(2), List.of(2), List.of(2, 2))));
+    }
+
+    record TestCase(List<Object> input, List<List<Object>> expected) {
+    }
+}

From c42b1c940c0b671b9da2ed692e14c5088c3abe58 Mon Sep 17 00:00:00 2001
From: Godwill Christopher <chrisgodswill115@gmail.com>
Date: Fri, 31 May 2024 14:01:11 -0600
Subject: [PATCH 0184/1338] style: enable `ParameterName` in CheckStyle.
 (#5196)

* Enabled: ParameterName in CheckStyle.

* Refactored to fix  bug caused by selfAssignment of variables in VectorCrossproduct class
---
 checkstyle.xml                                |  2 +-
 .../thealgorithms/backtracking/PowerSum.java  | 20 ++++----
 .../conversions/RomanToInteger.java           | 16 +++----
 .../graphs/BipartiteGrapfDFS.java             | 12 ++---
 .../datastructures/graphs/FloydWarshall.java  |  4 +-
 .../graphs/TarjansAlgorithm.java              | 12 ++---
 .../hashing/GenericHashMapUsingArray.java     |  4 +-
 .../lists/Merge_K_SortedLinkedlist.java       |  6 +--
 .../datastructures/trees/SegmentTree.java     | 18 ++++----
 .../BinaryExponentiation.java                 | 10 ++--
 .../dynamicprogramming/BoundaryFill.java      | 46 +++++++++----------
 .../BruteForceKnapsack.java                   | 10 ++--
 .../dynamicprogramming/KadaneAlgorithm.java   |  4 +-
 .../dynamicprogramming/NewManShanksPrime.java |  4 +-
 .../dynamicprogramming/SumOfSubset.java       | 10 ++--
 .../com/thealgorithms/maths/Convolution.java  | 14 +++---
 .../com/thealgorithms/maths/Gaussian.java     | 34 +++++++-------
 .../com/thealgorithms/maths/PronicNumber.java |  8 ++--
 .../maths/VectorCrossProduct.java             | 14 +++---
 .../java/com/thealgorithms/others/KMP.java    |  8 ++--
 .../com/thealgorithms/others/PasswordGen.java |  4 +-
 .../scheduling/SJFScheduling.java             | 14 +++---
 .../com/thealgorithms/sorts/BitonicSort.java  |  4 +-
 23 files changed, 139 insertions(+), 139 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index de7c70266bfb..5ada9361d03c 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -114,7 +114,7 @@
     <module name="MemberName"/>
     <module name="MethodName"/>
     <module name="PackageName"/>
-    <!-- TODO <module name="ParameterName"/> -->
+    <module name="ParameterName"/>
     <module name="StaticVariableName"/>
     <!-- TODO <module name="TypeName"/> -->
 
diff --git a/src/main/java/com/thealgorithms/backtracking/PowerSum.java b/src/main/java/com/thealgorithms/backtracking/PowerSum.java
index 8c46fb1c924a..6617ea326a1c 100644
--- a/src/main/java/com/thealgorithms/backtracking/PowerSum.java
+++ b/src/main/java/com/thealgorithms/backtracking/PowerSum.java
@@ -11,30 +11,30 @@ public class PowerSum {
     private int count = 0;
     private int sum = 0;
 
-    public int powSum(int N, int X) {
-        sum(N, X, 1);
+    public int powSum(int n, int x) {
+        sum(n, x, 1);
         return count;
     }
 
     // here i is the natural number which will be raised by X and added in sum.
-    public void sum(int N, int X, int i) {
+    public void sum(int n, int x, int i) {
         // if sum is equal to N that is one of our answer and count is increased.
-        if (sum == N) {
+        if (sum == n) {
             count++;
             return;
         } // we will be adding next natural number raised to X only if on adding it in sum the
           // result is less than N.
-        else if (sum + power(i, X) <= N) {
-            sum += power(i, X);
-            sum(N, X, i + 1);
+        else if (sum + power(i, x) <= n) {
+            sum += power(i, x);
+            sum(n, x, i + 1);
             // backtracking and removing the number added last since no possible combination is
             // there with it.
-            sum -= power(i, X);
+            sum -= power(i, x);
         }
-        if (power(i, X) < N) {
+        if (power(i, x) < n) {
             // calling the sum function with next natural number after backtracking if when it is
             // raised to X is still less than X.
-            sum(N, X, i + 1);
+            sum(n, x, i + 1);
         }
     }
 
diff --git a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
index 6ffb41c3c0e2..cf2d4145858f 100644
--- a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
+++ b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
@@ -24,31 +24,31 @@ private RomanToInteger() {
     /**
      * This function convert Roman number into Integer
      *
-     * @param A Roman number string
+     * @param a Roman number string
      * @return integer
      */
-    public static int romanToInt(String A) {
-        A = A.toUpperCase();
+    public static int romanToInt(String a) {
+        a = a.toUpperCase();
         char prev = ' ';
 
         int sum = 0;
 
         int newPrev = 0;
-        for (int i = A.length() - 1; i >= 0; i--) {
-            char c = A.charAt(i);
+        for (int i = a.length() - 1; i >= 0; i--) {
+            char c = a.charAt(i);
 
             if (prev != ' ') {
-                // checking current Number greater then previous or not
+                // checking current Number greater than previous or not
                 newPrev = ROMAN_TO_INT.get(prev) > newPrev ? ROMAN_TO_INT.get(prev) : newPrev;
             }
 
             int currentNum = ROMAN_TO_INT.get(c);
 
-            // if current number greater then prev max previous then add
+            // if current number greater than prev max previous then add
             if (currentNum >= newPrev) {
                 sum += currentNum;
             } else {
-                // subtract upcoming number until upcoming number not greater then prev max
+                // subtract upcoming number until upcoming number not greater than prev max
                 sum -= currentNum;
             }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java b/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
index 1e82ca0cd421..4cc14bfd38de 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
@@ -18,14 +18,14 @@ public final class BipartiteGrapfDFS {
     private BipartiteGrapfDFS() {
     }
 
-    private static boolean bipartite(int V, ArrayList<ArrayList<Integer>> adj, int[] color, int node) {
+    private static boolean bipartite(int v, ArrayList<ArrayList<Integer>> adj, int[] color, int node) {
         if (color[node] == -1) {
             color[node] = 1;
         }
         for (Integer it : adj.get(node)) {
             if (color[it] == -1) {
                 color[it] = 1 - color[node];
-                if (!bipartite(V, adj, color, it)) {
+                if (!bipartite(v, adj, color, it)) {
                     return false;
                 }
             } else if (color[it] == color[node]) {
@@ -35,14 +35,14 @@ private static boolean bipartite(int V, ArrayList<ArrayList<Integer>> adj, int[]
         return true;
     }
 
-    public static boolean isBipartite(int V, ArrayList<ArrayList<Integer>> adj) {
+    public static boolean isBipartite(int v, ArrayList<ArrayList<Integer>> adj) {
         // Code here
-        int[] color = new int[V + 1];
+        int[] color = new int[v + 1];
         Arrays.fill(color, -1);
 
-        for (int i = 0; i < V; i++) {
+        for (int i = 0; i < v; i++) {
             if (color[i] == -1) {
-                if (!bipartite(V, adj, color, i)) {
+                if (!bipartite(v, adj, color, i)) {
                     return false;
                 }
             }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java b/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
index a574b40daec6..d47ffe3aa27d 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
@@ -15,10 +15,10 @@ public FloydWarshall(int numberofvertices) {
         this.numberofvertices = numberofvertices;
     }
 
-    public void floydwarshall(int[][] AdjacencyMatrix) { // calculates all the distances from source to destination vertex
+    public void floydwarshall(int[][] adjacencyMatrix) { // calculates all the distances from source to destination vertex
         for (int source = 1; source <= numberofvertices; source++) {
             for (int destination = 1; destination <= numberofvertices; destination++) {
-                distanceMatrix[source][destination] = AdjacencyMatrix[source][destination];
+                distanceMatrix[source][destination] = adjacencyMatrix[source][destination];
             }
         }
         for (int intermediate = 1; intermediate <= numberofvertices; intermediate++) {
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
index 251c169d11ac..987e73a2a5d5 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
@@ -60,7 +60,7 @@ public class TarjansAlgorithm {
 
     private List<List<Integer>> sccList = new ArrayList<List<Integer>>();
 
-    public List<List<Integer>> stronglyConnectedComponents(int V, List<List<Integer>> graph) {
+    public List<List<Integer>> stronglyConnectedComponents(int v, List<List<Integer>> graph) {
 
         // Initially all vertices as unvisited, insertion and low time are undefined
 
@@ -68,20 +68,20 @@ public List<List<Integer>> stronglyConnectedComponents(int V, List<List<Integer>
 
         // lowTime: indicates the earliest visited vertex (the vertex with minimum insertion time)
         // that can be reached from a subtree rooted with a particular node.
-        int[] lowTime = new int[V];
-        int[] insertionTime = new int[V];
-        for (int i = 0; i < V; i++) {
+        int[] lowTime = new int[v];
+        int[] insertionTime = new int[v];
+        for (int i = 0; i < v; i++) {
             insertionTime[i] = -1;
             lowTime[i] = -1;
         }
 
         // To check if element is present in stack
-        boolean[] isInStack = new boolean[V];
+        boolean[] isInStack = new boolean[v];
 
         // Store nodes during DFS
         Stack<Integer> st = new Stack<Integer>();
 
-        for (int i = 0; i < V; i++) {
+        for (int i = 0; i < v; i++) {
             if (insertionTime[i] == -1) stronglyConnCompsUtil(i, lowTime, insertionTime, isInStack, st, graph);
         }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
index 5a1ab7b6174b..9fbb2ff0ad62 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
@@ -19,8 +19,8 @@ public GenericHashMapUsingArray() {
     // 75, then adding 76th item it will double the size, copy all elements
     // & then add 76th item.
 
-    private void initBuckets(int N) {
-        buckets = new LinkedList[N];
+    private void initBuckets(int n) {
+        buckets = new LinkedList[n];
         for (int i = 0; i < buckets.length; i++) {
             buckets[i] = new LinkedList<>();
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java b/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java
index d98335b1e5b9..a714eda18bcd 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java
@@ -13,15 +13,15 @@ public class Merge_K_SortedLinkedlist {
      * This function merge K sorted LinkedList
      *
      * @param a array of LinkedList
-     * @param N size of array
+     * @param n size of array
      * @return node
      */
-    Node mergeKList(Node[] a, int N) {
+    Node mergeKList(Node[] a, int n) {
         // Min Heap
         PriorityQueue<Node> min = new PriorityQueue<>(Comparator.comparingInt(x -> x.data));
 
         // adding head of all linkedList in min heap
-        min.addAll(Arrays.asList(a).subList(0, N));
+        min.addAll(Arrays.asList(a).subList(0, n));
 
         // Make new head among smallest heads in K linkedList
         Node head = min.poll();
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
index a6a76f8f094f..57b3edc163ca 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
@@ -32,16 +32,16 @@ public final int constructTree(int[] arr, int start, int end, int index) {
 
     /* A function which will update the value at a index i. This will be called by the
     update function internally*/
-    private void updateTree(int start, int end, int index, int diff, int seg_index) {
+    private void updateTree(int start, int end, int index, int diff, int segIndex) {
         if (index < start || index > end) {
             return;
         }
 
-        this.segTree[seg_index] += diff;
+        this.segTree[segIndex] += diff;
         if (start != end) {
             int mid = start + (end - start) / 2;
-            updateTree(start, mid, index, diff, seg_index * 2 + 1);
-            updateTree(mid + 1, end, index, diff, seg_index * 2 + 2);
+            updateTree(start, mid, index, diff, segIndex * 2 + 1);
+            updateTree(mid + 1, end, index, diff, segIndex * 2 + 2);
         }
     }
 
@@ -58,17 +58,17 @@ public void update(int index, int value) {
 
     /* A function to get the sum of the elements from index l to index r. This will be called
      * internally*/
-    private int getSumTree(int start, int end, int q_start, int q_end, int seg_index) {
-        if (q_start <= start && q_end >= end) {
-            return this.segTree[seg_index];
+    private int getSumTree(int start, int end, int qStart, int qEnd, int segIndex) {
+        if (qStart <= start && qEnd >= end) {
+            return this.segTree[segIndex];
         }
 
-        if (q_start > end || q_end < start) {
+        if (qStart > end || qEnd < start) {
             return 0;
         }
 
         int mid = start + (end - start) / 2;
-        return (getSumTree(start, mid, q_start, q_end, seg_index * 2 + 1) + getSumTree(mid + 1, end, q_start, q_end, seg_index * 2 + 2));
+        return (getSumTree(start, mid, qStart, qEnd, segIndex * 2 + 1) + getSumTree(mid + 1, end, qStart, qEnd, segIndex * 2 + 2));
     }
 
     /* A function to query the sum of the subarray [start...end]*/
diff --git a/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java b/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java
index 7c28797c0791..de829585891a 100644
--- a/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java
+++ b/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java
@@ -27,15 +27,15 @@ public static long calculatePower(long x, long y) {
     }
 
     // iterative function to calculate a to the power of b
-    long power(long N, long M) {
-        long power = N;
+    long power(long n, long m) {
+        long power = n;
         long sum = 1;
-        while (M > 0) {
-            if ((M & 1) == 1) {
+        while (m > 0) {
+            if ((m & 1) == 1) {
                 sum *= power;
             }
             power = power * power;
-            M = M >> 1;
+            m = m >> 1;
         }
         return sum;
     }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java b/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
index 7fa4e24383a8..3fa8728930cb 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
@@ -12,44 +12,44 @@ private BoundaryFill() {
      * Get the color at the given co-odrinates of a 2D image
      *
      * @param image The image to be filled
-     * @param x_co_ordinate The x co-ordinate of which color is to be obtained
-     * @param y_co_ordinate The y co-ordinate of which color is to be obtained
+     * @param xCoordinate The x co-ordinate of which color is to be obtained
+     * @param yCoordinate The y co-ordinate of which color is to be obtained
      */
-    public static int getPixel(int[][] image, int x_co_ordinate, int y_co_ordinate) {
-        return image[x_co_ordinate][y_co_ordinate];
+    public static int getPixel(int[][] image, int xCoordinate, int yCoordinate) {
+        return image[xCoordinate][yCoordinate];
     }
 
     /**
      * Put the color at the given co-odrinates of a 2D image
      *
      * @param image The image to be filed
-     * @param x_co_ordinate The x co-ordinate at which color is to be filled
-     * @param y_co_ordinate The y co-ordinate at which color is to be filled
+     * @param xCoordinate The x co-ordinate at which color is to be filled
+     * @param yCoordinate The y co-ordinate at which color is to be filled
      */
-    public static void putPixel(int[][] image, int x_co_ordinate, int y_co_ordinate, int new_color) {
-        image[x_co_ordinate][y_co_ordinate] = new_color;
+    public static void putPixel(int[][] image, int xCoordinate, int yCoordinate, int newColor) {
+        image[xCoordinate][yCoordinate] = newColor;
     }
 
     /**
      * Fill the 2D image with new color
      *
      * @param image The image to be filed
-     * @param x_co_ordinate The x co-ordinate at which color is to be filled
-     * @param y_co_ordinate The y co-ordinate at which color is to be filled
-     * @param new_color The new color which to be filled in the image
-     * @param boundary_color The old color which is to be replaced in the image
+     * @param xCoordinate The x co-ordinate at which color is to be filled
+     * @param yCoordinate The y co-ordinate at which color is to be filled
+     * @param newColor The new color which to be filled in the image
+     * @param boundaryColor The old color which is to be replaced in the image
      */
-    public static void boundaryFill(int[][] image, int x_co_ordinate, int y_co_ordinate, int new_color, int boundary_color) {
-        if (x_co_ordinate >= 0 && y_co_ordinate >= 0 && getPixel(image, x_co_ordinate, y_co_ordinate) != new_color && getPixel(image, x_co_ordinate, y_co_ordinate) != boundary_color) {
-            putPixel(image, x_co_ordinate, y_co_ordinate, new_color);
-            boundaryFill(image, x_co_ordinate + 1, y_co_ordinate, new_color, boundary_color);
-            boundaryFill(image, x_co_ordinate - 1, y_co_ordinate, new_color, boundary_color);
-            boundaryFill(image, x_co_ordinate, y_co_ordinate + 1, new_color, boundary_color);
-            boundaryFill(image, x_co_ordinate, y_co_ordinate - 1, new_color, boundary_color);
-            boundaryFill(image, x_co_ordinate + 1, y_co_ordinate - 1, new_color, boundary_color);
-            boundaryFill(image, x_co_ordinate - 1, y_co_ordinate + 1, new_color, boundary_color);
-            boundaryFill(image, x_co_ordinate + 1, y_co_ordinate + 1, new_color, boundary_color);
-            boundaryFill(image, x_co_ordinate - 1, y_co_ordinate - 1, new_color, boundary_color);
+    public static void boundaryFill(int[][] image, int xCoordinate, int yCoordinate, int newColor, int boundaryColor) {
+        if (xCoordinate >= 0 && yCoordinate >= 0 && getPixel(image, xCoordinate, yCoordinate) != newColor && getPixel(image, xCoordinate, yCoordinate) != boundaryColor) {
+            putPixel(image, xCoordinate, yCoordinate, newColor);
+            boundaryFill(image, xCoordinate + 1, yCoordinate, newColor, boundaryColor);
+            boundaryFill(image, xCoordinate - 1, yCoordinate, newColor, boundaryColor);
+            boundaryFill(image, xCoordinate, yCoordinate + 1, newColor, boundaryColor);
+            boundaryFill(image, xCoordinate, yCoordinate - 1, newColor, boundaryColor);
+            boundaryFill(image, xCoordinate + 1, yCoordinate - 1, newColor, boundaryColor);
+            boundaryFill(image, xCoordinate - 1, yCoordinate + 1, newColor, boundaryColor);
+            boundaryFill(image, xCoordinate + 1, yCoordinate + 1, newColor, boundaryColor);
+            boundaryFill(image, xCoordinate - 1, yCoordinate - 1, newColor, boundaryColor);
         }
     }
 
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java b/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
index 1daac91c5b4b..b433c44b9077 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
@@ -8,9 +8,9 @@ private BruteForceKnapsack() {
     // Returns the maximum value that
     // can be put in a knapsack of
     // capacity W
-    static int knapSack(int W, int[] wt, int[] val, int n) {
+    static int knapSack(int w, int[] wt, int[] val, int n) {
         // Base Case
-        if (n == 0 || W == 0) {
+        if (n == 0 || w == 0) {
             return 0;
         }
 
@@ -18,13 +18,13 @@ static int knapSack(int W, int[] wt, int[] val, int n) {
         // more than Knapsack capacity W,
         // then this item cannot be included
         // in the optimal solution
-        if (wt[n - 1] > W) {
-            return knapSack(W, wt, val, n - 1);
+        if (wt[n - 1] > w) {
+            return knapSack(w, wt, val, n - 1);
         } // Return the maximum of two cases:
         // (1) nth item included
         // (2) not included
         else {
-            return Math.max(val[n - 1] + knapSack(W - wt[n - 1], wt, val, n - 1), knapSack(W, wt, val, n - 1));
+            return Math.max(val[n - 1] + knapSack(w - wt[n - 1], wt, val, n - 1), knapSack(w, wt, val, n - 1));
         }
     }
 
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
index e1f0aeabe14d..de75126044ae 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
@@ -10,7 +10,7 @@ public final class KadaneAlgorithm {
     private KadaneAlgorithm() {
     }
 
-    public static boolean maxSum(int[] a, int predicted_answer) {
+    public static boolean maxSum(int[] a, int predictedAnswer) {
         int sum = a[0];
         int runningSum = 0;
         for (int k : a) {
@@ -22,7 +22,7 @@ public static boolean maxSum(int[] a, int predicted_answer) {
             // if running sum is negative then it is initialized to zero
         }
         // for-each loop is used to iterate over the array and find the maximum subarray sum
-        return sum == predicted_answer;
+        return sum == predictedAnswer;
         // It returns true if sum and predicted answer matches
         // The predicted answer is the answer itself. So it always return true
     }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java b/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
index 7bc383656581..5d31d40dacdc 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
@@ -12,7 +12,7 @@ public final class NewManShanksPrime {
     private NewManShanksPrime() {
     }
 
-    public static boolean nthManShanksPrime(int n, int expected_answer) {
+    public static boolean nthManShanksPrime(int n, int expectedAnswer) {
         int[] a = new int[n + 1];
         // array of n+1 size is initialized
         a[0] = 1;
@@ -22,7 +22,7 @@ public static boolean nthManShanksPrime(int n, int expected_answer) {
             a[i] = 2 * a[i - 1] + a[i - 2];
         }
         // The loop is continued till n
-        return a[n] == expected_answer;
+        return a[n] == expectedAnswer;
         // returns true if calculated answer matches with expected answer
     }
 }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java b/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
index a2e641095c9f..dd48008bd21e 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
@@ -4,16 +4,16 @@ public final class SumOfSubset {
     private SumOfSubset() {
     }
 
-    public static boolean subsetSum(int[] arr, int num, int Key) {
-        if (Key == 0) {
+    public static boolean subsetSum(int[] arr, int num, int key) {
+        if (key == 0) {
             return true;
         }
-        if (num < 0 || Key < 0) {
+        if (num < 0 || key < 0) {
             return false;
         }
 
-        boolean include = subsetSum(arr, num - 1, Key - arr[num]);
-        boolean exclude = subsetSum(arr, num - 1, Key);
+        boolean include = subsetSum(arr, num - 1, key - arr[num]);
+        boolean exclude = subsetSum(arr, num - 1, key);
 
         return include || exclude;
     }
diff --git a/src/main/java/com/thealgorithms/maths/Convolution.java b/src/main/java/com/thealgorithms/maths/Convolution.java
index 4dd4eb3e99f5..93e103f8c7cf 100644
--- a/src/main/java/com/thealgorithms/maths/Convolution.java
+++ b/src/main/java/com/thealgorithms/maths/Convolution.java
@@ -15,12 +15,12 @@ private Convolution() {
      * signal must start from 0. If you have a signal that has values before 0
      * then shift it to start from 0.
      *
-     * @param A The first discrete signal
-     * @param B The second discrete signal
+     * @param a The first discrete signal
+     * @param b The second discrete signal
      * @return The convolved signal
      */
-    public static double[] convolution(double[] A, double[] B) {
-        double[] convolved = new double[A.length + B.length - 1];
+    public static double[] convolution(double[] a, double[] b) {
+        double[] convolved = new double[a.length + b.length - 1];
 
         /*
     The discrete convolution of two signals A and B is defined as:
@@ -35,10 +35,10 @@ public static double[] convolution(double[] A, double[] B) {
          */
         for (int i = 0; i < convolved.length; i++) {
             convolved[i] = 0;
-            int k = Math.max(i - B.length + 1, 0);
+            int k = Math.max(i - b.length + 1, 0);
 
-            while (k < i + 1 && k < A.length) {
-                convolved[i] += A[k] * B[i - k];
+            while (k < i + 1 && k < a.length) {
+                convolved[i] += a[k] * b[i - k];
                 k++;
             }
         }
diff --git a/src/main/java/com/thealgorithms/maths/Gaussian.java b/src/main/java/com/thealgorithms/maths/Gaussian.java
index 07c0f67f06e2..cefbaea5b9b4 100644
--- a/src/main/java/com/thealgorithms/maths/Gaussian.java
+++ b/src/main/java/com/thealgorithms/maths/Gaussian.java
@@ -6,34 +6,34 @@ public final class Gaussian {
     private Gaussian() {
     }
 
-    public static ArrayList<Double> gaussian(int mat_size, ArrayList<Double> matrix) {
+    public static ArrayList<Double> gaussian(int matSize, ArrayList<Double> matrix) {
         ArrayList<Double> answerArray = new ArrayList<Double>();
         int i;
         int j = 0;
 
-        double[][] mat = new double[mat_size + 1][mat_size + 1];
-        double[][] x = new double[mat_size][mat_size + 1];
+        double[][] mat = new double[matSize + 1][matSize + 1];
+        double[][] x = new double[matSize][matSize + 1];
 
         // Values from arraylist to matrix
-        for (i = 0; i < mat_size; i++) {
-            for (j = 0; j <= mat_size; j++) {
+        for (i = 0; i < matSize; i++) {
+            for (j = 0; j <= matSize; j++) {
                 mat[i][j] = matrix.get(i);
             }
         }
 
-        mat = gaussianElimination(mat_size, i, mat);
-        answerArray = valueOfGaussian(mat_size, x, mat);
+        mat = gaussianElimination(matSize, i, mat);
+        answerArray = valueOfGaussian(matSize, x, mat);
         return answerArray;
     }
 
     // Perform Gaussian elimination
-    public static double[][] gaussianElimination(int mat_size, int i, double[][] mat) {
+    public static double[][] gaussianElimination(int matSize, int i, double[][] mat) {
         int step = 0;
-        for (step = 0; step < mat_size - 1; step++) {
-            for (i = step; i < mat_size - 1; i++) {
+        for (step = 0; step < matSize - 1; step++) {
+            for (i = step; i < matSize - 1; i++) {
                 double a = (mat[i + 1][step] / mat[step][step]);
 
-                for (int j = step; j <= mat_size; j++) {
+                for (int j = step; j <= matSize; j++) {
                     mat[i + 1][j] = mat[i + 1][j] - (a * mat[step][j]);
                 }
             }
@@ -42,27 +42,27 @@ public static double[][] gaussianElimination(int mat_size, int i, double[][] mat
     }
 
     // calculate the x_1, x_2, ... values of the gaussian and save it in an arraylist.
-    public static ArrayList<Double> valueOfGaussian(int mat_size, double[][] x, double[][] mat) {
+    public static ArrayList<Double> valueOfGaussian(int matSize, double[][] x, double[][] mat) {
         ArrayList<Double> answerArray = new ArrayList<Double>();
         int i;
         int j;
 
-        for (i = 0; i < mat_size; i++) {
-            for (j = 0; j <= mat_size; j++) {
+        for (i = 0; i < matSize; i++) {
+            for (j = 0; j <= matSize; j++) {
                 x[i][j] = mat[i][j];
             }
         }
 
-        for (i = mat_size - 1; i >= 0; i--) {
+        for (i = matSize - 1; i >= 0; i--) {
             double sum = 0;
-            for (j = mat_size - 1; j > i; j--) {
+            for (j = matSize - 1; j > i; j--) {
                 x[i][j] = x[j][j] * x[i][j];
                 sum = x[i][j] + sum;
             }
             if (x[i][i] == 0) {
                 x[i][i] = 0;
             } else {
-                x[i][i] = (x[i][mat_size] - sum) / (x[i][i]);
+                x[i][i] = (x[i][matSize] - sum) / (x[i][i]);
             }
             answerArray.add(x[i][j]);
         }
diff --git a/src/main/java/com/thealgorithms/maths/PronicNumber.java b/src/main/java/com/thealgorithms/maths/PronicNumber.java
index 1ae53c4c4429..4891cf3c63b3 100644
--- a/src/main/java/com/thealgorithms/maths/PronicNumber.java
+++ b/src/main/java/com/thealgorithms/maths/PronicNumber.java
@@ -17,14 +17,14 @@ private PronicNumber() {
     /**
      * This method checks if the given number is pronic number or non-pronic number
      *
-     * @param input_number Integer value which is to be checked if is a pronic number or not
+     * @param inputNumber Integer value which is to be checked if is a pronic number or not
      * @return true if input number is a pronic number, false otherwise
      */
-    static boolean isPronic(int input_number) {
+    static boolean isPronic(int inputNumber) {
         // Iterating from 0 to input_number
-        for (int i = 0; i <= input_number; i++) {
+        for (int i = 0; i <= inputNumber; i++) {
             // Checking if product of i and (i+1) is equals input_number
-            if (i * (i + 1) == input_number && i != input_number) {
+            if (i * (i + 1) == inputNumber && i != inputNumber) {
                 // return true if product of i and (i+1) is equals input_number
                 return true;
             }
diff --git a/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java b/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java
index 8b93702b9514..e2769744bcda 100644
--- a/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java
+++ b/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java
@@ -55,14 +55,14 @@ public class VectorCrossProduct {
     /**
      * constructor, initialises Vector with given Direction Ratios
      *
-     * @param _x set to x
-     * @param _y set to y
-     * @param _z set to z
+     * @param vectorX set to x
+     * @param vectorY set to y
+     * @param vectorZ set to z
      */
-    VectorCrossProduct(int _x, int _y, int _z) {
-        x = _x;
-        y = _y;
-        z = _z;
+    VectorCrossProduct(int vectorX, int vectorY, int vectorZ) {
+        x = vectorX;
+        y = vectorY;
+        z = vectorZ;
     }
 
     /**
diff --git a/src/main/java/com/thealgorithms/others/KMP.java b/src/main/java/com/thealgorithms/others/KMP.java
index 7df5d1a8a5bd..73eaf2fc9beb 100644
--- a/src/main/java/com/thealgorithms/others/KMP.java
+++ b/src/main/java/com/thealgorithms/others/KMP.java
@@ -39,17 +39,17 @@ public static void kmpMatcher(final String haystack, final String needle) {
     }
 
     // return the prefix function
-    private static int[] computePrefixFunction(final String P) {
-        final int n = P.length();
+    private static int[] computePrefixFunction(final String p) {
+        final int n = p.length();
         final int[] pi = new int[n];
         pi[0] = 0;
         int q = 0;
         for (int i = 1; i < n; i++) {
-            while (q > 0 && P.charAt(q) != P.charAt(i)) {
+            while (q > 0 && p.charAt(q) != p.charAt(i)) {
                 q = pi[q - 1];
             }
 
-            if (P.charAt(q) == P.charAt(i)) {
+            if (p.charAt(q) == p.charAt(i)) {
                 q++;
             }
 
diff --git a/src/main/java/com/thealgorithms/others/PasswordGen.java b/src/main/java/com/thealgorithms/others/PasswordGen.java
index f982848a5c1a..7d21f112d480 100644
--- a/src/main/java/com/thealgorithms/others/PasswordGen.java
+++ b/src/main/java/com/thealgorithms/others/PasswordGen.java
@@ -15,7 +15,7 @@ final class PasswordGen {
     private PasswordGen() {
     }
 
-    static String generatePassword(int min_length, int max_length) {
+    static String generatePassword(int minLength, int maxLength) {
         Random random = new Random();
 
         String upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
@@ -35,7 +35,7 @@ static String generatePassword(int min_length, int max_length) {
         StringBuilder password = new StringBuilder();
 
         // Note that size of the password is also random
-        for (int i = random.nextInt(max_length - min_length) + min_length; i > 0; --i) {
+        for (int i = random.nextInt(maxLength - minLength) + minLength; i > 0; --i) {
             password.append(letters.get(random.nextInt(letters.size())));
         }
 
diff --git a/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java b/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
index c14c91ba6c37..ca2144e4924f 100644
--- a/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
@@ -83,28 +83,28 @@ public void scheduleProcesses() {
     /**
      * this function evaluates the shortest job of all the ready processes (based on  a process
      * burst time)
-     * @param ReadyProcesses an array list of ready processes
+     * @param readyProcesses an array list of ready processes
      * @return returns the process' with the shortest burst time OR NULL if there are no ready
      *     processes
      */
-    private ProcessDetails findShortestJob(ArrayList<ProcessDetails> ReadyProcesses) {
-        if (ReadyProcesses.isEmpty()) {
+    private ProcessDetails findShortestJob(ArrayList<ProcessDetails> readyProcesses) {
+        if (readyProcesses.isEmpty()) {
             return null;
         }
         int i;
-        int size = ReadyProcesses.size();
-        int minBurstTime = ReadyProcesses.get(0).getBurstTime();
+        int size = readyProcesses.size();
+        int minBurstTime = readyProcesses.get(0).getBurstTime();
         int temp;
         int positionOfShortestJob = 0;
 
         for (i = 1; i < size; i++) {
-            temp = ReadyProcesses.get(i).getBurstTime();
+            temp = readyProcesses.get(i).getBurstTime();
             if (minBurstTime > temp) {
                 minBurstTime = temp;
                 positionOfShortestJob = i;
             }
         }
 
-        return ReadyProcesses.get(positionOfShortestJob);
+        return readyProcesses.get(positionOfShortestJob);
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/BitonicSort.java b/src/main/java/com/thealgorithms/sorts/BitonicSort.java
index 346d860508ca..b4b26299562f 100644
--- a/src/main/java/com/thealgorithms/sorts/BitonicSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BitonicSort.java
@@ -55,8 +55,8 @@ void bitonicSort(int[] a, int low, int cnt, int dir) {
 
     /*Caller of bitonicSort for sorting the entire array
   of length N in ASCENDING order */
-    void sort(int[] a, int N, int up) {
-        bitonicSort(a, 0, N, up);
+    void sort(int[] a, int n, int up) {
+        bitonicSort(a, 0, n, up);
     }
 
     /* A utility function to print array of size n */

From 5e4db7baf1346441d798075cbc57160fe6f580e9 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 1 Jun 2024 23:24:11 +0200
Subject: [PATCH 0185/1338] style: include `SS_SHOULD_BE_STATIC` (#5198)

---
 spotbugs-exclude.xml                          |  3 -
 .../conversions/HexaDecimalToBinary.java      |  4 +-
 .../datastructures/trees/RedBlackBST.java     | 92 +++++++++----------
 3 files changed, 47 insertions(+), 52 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 02e03725c429..18aaab94b435 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -77,9 +77,6 @@
     <Match>
         <Bug pattern="UWF_UNWRITTEN_FIELD" />
     </Match>
-    <Match>
-        <Bug pattern="SS_SHOULD_BE_STATIC" />
-    </Match>
     <Match>
         <Bug pattern="IT_NO_SUCH_ELEMENT" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java b/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
index c766b83f1c7b..b6228488dc76 100644
--- a/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
+++ b/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
@@ -2,9 +2,6 @@
 
 // Hex [0-9],[A-F] -> Binary [0,1]
 public class HexaDecimalToBinary {
-
-    private final int longBits = 8;
-
     public String convert(String numHex) {
         // String a HexaDecimal:
         int conHex = Integer.parseInt(numHex, 16);
@@ -15,6 +12,7 @@ public String convert(String numHex) {
     }
 
     public String completeDigits(String binNum) {
+        final int longBits = 8;
         for (int i = binNum.length(); i < longBits; i++) {
             binNum = "0" + binNum;
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java b/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
index 2961282efe75..01222b739ff0 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java
@@ -7,13 +7,13 @@
  */
 public class RedBlackBST {
 
-    private final int red = 0;
-    private final int black = 1;
+    private static final int RED = 0;
+    private static final int BLACK = 1;
 
     private class Node {
 
         int key = -1;
-        int color = black;
+        int color = BLACK;
         Node left = nil;
         Node right = nil;
         Node p = nil;
@@ -31,7 +31,7 @@ public void printTree(Node node) {
             return;
         }
         printTree(node.left);
-        System.out.print(((node.color == red) ? " R " : " B ") + "Key: " + node.key + " Parent: " + node.p.key + "\n");
+        System.out.print(((node.color == RED) ? " R " : " B ") + "Key: " + node.key + " Parent: " + node.p.key + "\n");
         printTree(node.right);
     }
 
@@ -39,7 +39,7 @@ public void printTreepre(Node node) {
         if (node == nil) {
             return;
         }
-        System.out.print(((node.color == red) ? " R " : " B ") + "Key: " + node.key + " Parent: " + node.p.key + "\n");
+        System.out.print(((node.color == RED) ? " R " : " B ") + "Key: " + node.key + " Parent: " + node.p.key + "\n");
         printTreepre(node.left);
         printTreepre(node.right);
     }
@@ -66,10 +66,10 @@ private void insert(Node node) {
         Node temp = root;
         if (root == nil) {
             root = node;
-            node.color = black;
+            node.color = BLACK;
             node.p = nil;
         } else {
-            node.color = red;
+            node.color = RED;
             while (true) {
                 if (node.key < temp.key) {
                     if (temp.left == nil) {
@@ -94,15 +94,15 @@ private void insert(Node node) {
     }
 
     private void fixTree(Node node) {
-        while (node.p.color == red) {
+        while (node.p.color == RED) {
             Node y = nil;
             if (node.p == node.p.p.left) {
                 y = node.p.p.right;
 
-                if (y != nil && y.color == red) {
-                    node.p.color = black;
-                    y.color = black;
-                    node.p.p.color = red;
+                if (y != nil && y.color == RED) {
+                    node.p.color = BLACK;
+                    y.color = BLACK;
+                    node.p.p.color = RED;
                     node = node.p.p;
                     continue;
                 }
@@ -110,15 +110,15 @@ private void fixTree(Node node) {
                     node = node.p;
                     rotateLeft(node);
                 }
-                node.p.color = black;
-                node.p.p.color = red;
+                node.p.color = BLACK;
+                node.p.p.color = RED;
                 rotateRight(node.p.p);
             } else {
                 y = node.p.p.left;
-                if (y != nil && y.color == red) {
-                    node.p.color = black;
-                    y.color = black;
-                    node.p.p.color = red;
+                if (y != nil && y.color == RED) {
+                    node.p.color = BLACK;
+                    y.color = BLACK;
+                    node.p.p.color = RED;
                     node = node.p.p;
                     continue;
                 }
@@ -126,12 +126,12 @@ private void fixTree(Node node) {
                     node = node.p;
                     rotateRight(node);
                 }
-                node.p.color = black;
-                node.p.p.color = red;
+                node.p.color = BLACK;
+                node.p.p.color = RED;
                 rotateLeft(node.p.p);
             }
         }
-        root.color = black;
+        root.color = BLACK;
     }
 
     void rotateLeft(Node node) {
@@ -234,67 +234,67 @@ boolean delete(Node z) {
             y.left.p = y;
             y.color = z.color;
         }
-        if (yorigcolor == black) {
+        if (yorigcolor == BLACK) {
             deleteFixup(x);
         }
         return true;
     }
 
     void deleteFixup(Node x) {
-        while (x != root && x.color == black) {
+        while (x != root && x.color == BLACK) {
             if (x == x.p.left) {
                 Node w = x.p.right;
-                if (w.color == red) {
-                    w.color = black;
-                    x.p.color = red;
+                if (w.color == RED) {
+                    w.color = BLACK;
+                    x.p.color = RED;
                     rotateLeft(x.p);
                     w = x.p.right;
                 }
-                if (w.left.color == black && w.right.color == black) {
-                    w.color = red;
+                if (w.left.color == BLACK && w.right.color == BLACK) {
+                    w.color = RED;
                     x = x.p;
                     continue;
-                } else if (w.right.color == black) {
-                    w.left.color = black;
-                    w.color = red;
+                } else if (w.right.color == BLACK) {
+                    w.left.color = BLACK;
+                    w.color = RED;
                     rotateRight(w);
                     w = x.p.right;
                 }
-                if (w.right.color == red) {
+                if (w.right.color == RED) {
                     w.color = x.p.color;
-                    x.p.color = black;
-                    w.right.color = black;
+                    x.p.color = BLACK;
+                    w.right.color = BLACK;
                     rotateLeft(x.p);
                     x = root;
                 }
             } else {
                 Node w = x.p.left;
-                if (w.color == red) {
-                    w.color = black;
-                    x.p.color = red;
+                if (w.color == RED) {
+                    w.color = BLACK;
+                    x.p.color = RED;
                     rotateRight(x.p);
                     w = x.p.left;
                 }
-                if (w.right.color == black && w.left.color == black) {
-                    w.color = red;
+                if (w.right.color == BLACK && w.left.color == BLACK) {
+                    w.color = RED;
                     x = x.p;
                     continue;
-                } else if (w.left.color == black) {
-                    w.right.color = black;
-                    w.color = red;
+                } else if (w.left.color == BLACK) {
+                    w.right.color = BLACK;
+                    w.color = RED;
                     rotateLeft(w);
                     w = x.p.left;
                 }
-                if (w.left.color == red) {
+                if (w.left.color == RED) {
                     w.color = x.p.color;
-                    x.p.color = black;
-                    w.left.color = black;
+                    x.p.color = BLACK;
+                    w.left.color = BLACK;
                     rotateRight(x.p);
                     x = root;
                 }
             }
         }
-        x.color = black;
+        x.color = BLACK;
     }
 
     public void insertDemo() {

From 2e387fe54e9729cec4fe0604f1edd8642b02998c Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 1 Jun 2024 23:36:12 +0200
Subject: [PATCH 0186/1338] style: include `IMC_IMMATURE_CLASS_VAR_NAME`
 (#5197)

---
 spotbugs-exclude.xml                                      | 3 ---
 .../java/com/thealgorithms/maths/StandardDeviation.java   | 8 ++++----
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 18aaab94b435..711b34b0cc6f 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -216,9 +216,6 @@
     <Match>
         <Bug pattern="FCBL_FIELD_COULD_BE_LOCAL" />
     </Match>
-    <Match>
-        <Bug pattern="IMC_IMMATURE_CLASS_VAR_NAME" />
-    </Match>
     <Match>
         <Bug pattern="CFS_CONFUSING_FUNCTION_SEMANTICS" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/maths/StandardDeviation.java b/src/main/java/com/thealgorithms/maths/StandardDeviation.java
index 29ff070e9cff..a8e88d930a9c 100644
--- a/src/main/java/com/thealgorithms/maths/StandardDeviation.java
+++ b/src/main/java/com/thealgorithms/maths/StandardDeviation.java
@@ -5,16 +5,16 @@ private StandardDeviation() {
     }
 
     public static double stdDev(double[] data) {
-        double var = 0;
+        double variance = 0;
         double avg = 0;
         for (int i = 0; i < data.length; i++) {
             avg += data[i];
         }
         avg /= data.length;
         for (int j = 0; j < data.length; j++) {
-            var += Math.pow((data[j] - avg), 2);
+            variance += Math.pow((data[j] - avg), 2);
         }
-        var /= data.length;
-        return Math.sqrt(var);
+        variance /= data.length;
+        return Math.sqrt(variance);
     }
 }

From f3db69908394be2e2f184aea442f0c8a75038ddb Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 4 Jun 2024 07:56:59 +0200
Subject: [PATCH 0187/1338] Chore(deps): bump gitpod/workspace-java-21 from
 2024-05-27-17-11-15 to 2024-06-03-17-43-12 (#5201)

Chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2024-05-27-17-11-15 to 2024-06-03-17-43-12.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 1c1c0852d21c..82696623f953 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-05-27-17-11-15
+FROM gitpod/workspace-java-21:2024-06-03-17-43-12
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 493942e319dfe674f344d13e5df832d183bd11bd Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 4 Jun 2024 22:54:38 +0200
Subject: [PATCH 0188/1338] style: include `IT_NO_SUCH_ELEMENT` (#5200)

---
 spotbugs-exclude.xml                                       | 3 ---
 .../thealgorithms/datastructures/queues/LinkedQueue.java   | 7 +++++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 711b34b0cc6f..ae10d1045dfe 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -77,9 +77,6 @@
     <Match>
         <Bug pattern="UWF_UNWRITTEN_FIELD" />
     </Match>
-    <Match>
-        <Bug pattern="IT_NO_SUCH_ELEMENT" />
-    </Match>
     <Match>
         <Bug pattern="DLS_DEAD_LOCAL_STORE" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
index 8a788317c372..171f24e09396 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
@@ -148,8 +148,11 @@ public boolean hasNext() {
 
             @Override
             public T next() {
-                node = node.next;
-                return node.data;
+                if (hasNext()) {
+                    node = node.next;
+                    return node.data;
+                }
+                throw new NoSuchElementException();
             }
         };
     }

From 440f3ce18b4b3d019c4642e99a6b8b299fa72dba Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 4 Jun 2024 23:02:38 +0200
Subject: [PATCH 0189/1338] style: include `MAC_MANUAL_ARRAY_COPY` (#5199)

---
 spotbugs-exclude.xml                                        | 3 ---
 src/main/java/com/thealgorithms/others/BFPRT.java           | 4 +---
 .../java/com/thealgorithms/others/BankersAlgorithm.java     | 5 +----
 .../java/com/thealgorithms/others/ReturnSubsequence.java    | 6 ++----
 src/main/java/com/thealgorithms/sorts/RadixSort.java        | 4 +---
 5 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index ae10d1045dfe..f621c84dd4bf 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -138,9 +138,6 @@
     <Match>
         <Bug pattern="USBR_UNNECESSARY_STORE_BEFORE_RETURN" />
     </Match>
-    <Match>
-        <Bug pattern="MAC_MANUAL_ARRAY_COPY" />
-    </Match>
     <Match>
         <Bug pattern="SPP_USE_ISEMPTY" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/others/BFPRT.java b/src/main/java/com/thealgorithms/others/BFPRT.java
index 9e6fe6a3fbcc..1a5b44180651 100644
--- a/src/main/java/com/thealgorithms/others/BFPRT.java
+++ b/src/main/java/com/thealgorithms/others/BFPRT.java
@@ -34,9 +34,7 @@ public static int getMinKthByBFPRT(int[] arr, int k) {
 
     public static int[] copyArray(int[] arr) {
         int[] copyArr = new int[arr.length];
-        for (int i = 0; i < arr.length; i++) {
-            copyArr[i] = arr[i];
-        }
+        System.arraycopy(arr, 0, copyArr, 0, arr.length);
         return copyArr;
     }
 
diff --git a/src/main/java/com/thealgorithms/others/BankersAlgorithm.java b/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
index baa180431ce4..a22d7c737415 100644
--- a/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
@@ -60,10 +60,7 @@ static boolean checkSafeSystem(int[] processes, int[] availableArray, int[][] ma
         int[] safeSequenceArray = new int[totalProcess];
 
         int[] workArray = new int[totalResources];
-
-        for (int i = 0; i < totalResources; i++) {
-            workArray[i] = availableArray[i];
-        }
+        System.arraycopy(availableArray, 0, workArray, 0, totalResources);
 
         int count = 0;
 
diff --git a/src/main/java/com/thealgorithms/others/ReturnSubsequence.java b/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
index 81bd051ca365..ef376c47a8f8 100644
--- a/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
+++ b/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
@@ -34,10 +34,8 @@ private static String[] returnSubsequence(String givenString) {
         // position=1
 
         String[] ans = new String[2 * smallAns.length]; // Our answer will be an array off string of size=2*smallAns
-        int i = 0;
-        for (; i < smallAns.length; i++) {
-            ans[i] = smallAns[i]; // Copying all the strings present in smallAns to ans string array
-        }
+        System.arraycopy(smallAns, 0, ans, 0, smallAns.length);
+
         for (int k = 0; k < smallAns.length; k++) {
             ans[k + smallAns.length] = givenString.charAt(0) + smallAns[k]; // Insert character at index=0 of the given
                                                                             // substring in front of every string
diff --git a/src/main/java/com/thealgorithms/sorts/RadixSort.java b/src/main/java/com/thealgorithms/sorts/RadixSort.java
index 847b94036ca9..a87097bf6e9d 100644
--- a/src/main/java/com/thealgorithms/sorts/RadixSort.java
+++ b/src/main/java/com/thealgorithms/sorts/RadixSort.java
@@ -35,9 +35,7 @@ private static void countSort(int[] arr, int n, int exp) {
             count[(arr[i] / exp) % 10]--;
         }
 
-        for (i = 0; i < n; i++) {
-            arr[i] = output[i];
-        }
+        System.arraycopy(output, 0, arr, 0, n);
     }
 
     private static void radixsort(int[] arr, int n) {

From b315b7d578c22be59baeb1289394f1a0442943ff Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 5 Jun 2024 20:52:12 +0200
Subject: [PATCH 0190/1338] style: include `WMI_WRONG_MAP_ITERATOR` (#5206)

---
 spotbugs-exclude.xml                          |  3 ---
 .../datastructures/graphs/KahnsAlgorithm.java | 19 +++----------------
 .../hashmap/hashing/MajorityElement.java      |  6 +++---
 .../java/com/thealgorithms/maths/Mode.java    |  6 +++---
 4 files changed, 9 insertions(+), 25 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index f621c84dd4bf..ffafa51e76ed 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -68,9 +68,6 @@
     <Match>
         <Bug pattern="IM_BAD_CHECK_FOR_ODD" />
     </Match>
-    <Match>
-        <Bug pattern="WMI_WRONG_MAP_ITERATOR" />
-    </Match>
     <Match>
         <Bug pattern="DM_BOXED_PRIMITIVE_FOR_PARSING" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
index 145071890d76..be83ea32f496 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
@@ -54,19 +54,6 @@ ArrayList<E> getAdjacents(E v) {
     Set<E> getVertices() {
         return adj.keySet();
     }
-
-    /**
-     * Prints the adjacency list
-     */
-    void printGraph() {
-        for (E vertex : adj.keySet()) {
-            System.out.print(vertex + " : ");
-            for (E adjacent : adj.get(vertex)) {
-                System.out.print(adjacent + " ");
-            }
-            System.out.println();
-        }
-    }
 }
 
 class TopologicalSort<E extends Comparable<E>> {
@@ -104,9 +91,9 @@ ArrayList<E> topSortOrder() {
         calculateInDegree();
         Queue<E> q = new LinkedList<E>();
 
-        for (E vertex : inDegree.keySet()) {
-            if (inDegree.get(vertex) == 0) {
-                q.add(vertex);
+        for (final var entry : inDegree.entrySet()) {
+            if (entry.getValue() == 0) {
+                q.add(entry.getKey());
             }
         }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
index bfa5759a41b9..56d2b0ef930c 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
@@ -27,9 +27,9 @@ public static List<Integer> majority(int[] nums) {
             }
         }
         List<Integer> majorityElements = new ArrayList<>();
-        for (int key : numToCount.keySet()) {
-            if (numToCount.get(key) >= n / 2) {
-                majorityElements.add(key);
+        for (final var entry : numToCount.entrySet()) {
+            if (entry.getValue() >= n / 2) {
+                majorityElements.add(entry.getKey());
             }
         }
         return majorityElements;
diff --git a/src/main/java/com/thealgorithms/maths/Mode.java b/src/main/java/com/thealgorithms/maths/Mode.java
index a92f404c653a..f0b747cf02ec 100644
--- a/src/main/java/com/thealgorithms/maths/Mode.java
+++ b/src/main/java/com/thealgorithms/maths/Mode.java
@@ -38,9 +38,9 @@ public static int[] mode(final int[] numbers) {
         int max = Collections.max(count.values());
         ArrayList<Integer> modes = new ArrayList<>();
 
-        for (int num : count.keySet()) {
-            if (count.get(num) == max) {
-                modes.add(num);
+        for (final var entry : count.entrySet()) {
+            if (entry.getValue() == max) {
+                modes.add(entry.getKey());
             }
         }
         return modes.stream().mapToInt(n -> n).toArray();

From 732d5e06ae7ac179a052cdfbde5395df2a1d3708 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 5 Jun 2024 23:54:20 +0200
Subject: [PATCH 0191/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-checkstyle-plugin from 3.3.1 to 3.4.0 (#5208)

Chore(deps): bump org.apache.maven.plugins:maven-checkstyle-plugin

Bumps [org.apache.maven.plugins:maven-checkstyle-plugin](https://github.com/apache/maven-checkstyle-plugin) from 3.3.1 to 3.4.0.
- [Commits](https://github.com/apache/maven-checkstyle-plugin/compare/maven-checkstyle-plugin-3.3.1...maven-checkstyle-plugin-3.4.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-checkstyle-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b8fb946eeb5a..6e8c9acf92b0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -107,7 +107,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-checkstyle-plugin</artifactId>
-                <version>3.3.1</version>
+                <version>3.4.0</version>
                 <configuration>
                     <configLocation>checkstyle.xml</configLocation>
                     <consoleOutput>true</consoleOutput>

From 41efe7fbbc414fdf1cc06d7994f2edbf0d16a2ae Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 7 Jun 2024 19:59:53 +0200
Subject: [PATCH 0192/1338] style: include `DMC_DUBIOUS_MAP_COLLECTION` (#5207)

---
 spotbugs-exclude.xml                          |  3 --
 .../thealgorithms/maths/GenericRootTest.java  | 30 ++++++++++---------
 2 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index ffafa51e76ed..a01e489ba878 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -198,9 +198,6 @@
     <Match>
         <Bug pattern="ITU_INAPPROPRIATE_TOSTRING_USE" />
     </Match>
-    <Match>
-        <Bug pattern="DMC_DUBIOUS_MAP_COLLECTION" />
-    </Match>
     <Match>
         <Bug pattern="SPP_PASSING_THIS_AS_PARM" />
     </Match>
diff --git a/src/test/java/com/thealgorithms/maths/GenericRootTest.java b/src/test/java/com/thealgorithms/maths/GenericRootTest.java
index 50858cde1ef0..2578cfe82305 100644
--- a/src/test/java/com/thealgorithms/maths/GenericRootTest.java
+++ b/src/test/java/com/thealgorithms/maths/GenericRootTest.java
@@ -1,24 +1,26 @@
 package com.thealgorithms.maths;
 
-import static java.util.Map.entry;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.util.Map;
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class GenericRootTest {
-    private final Map<Integer, Integer> testCases = Map.ofEntries(entry(0, 0), entry(1, 1), entry(12345, 6), entry(123, 6), entry(15937, 7), entry(222222, 3), entry(99999, 9));
-    @Test
-    public void testGenericRoot() {
-        for (final var tc : testCases.entrySet()) {
-            assertEquals(tc.getValue(), GenericRoot.genericRoot(tc.getKey()));
-        }
+    @ParameterizedTest
+    @MethodSource("tcStream")
+    public void testGenericRoot(final int input, final int expected) {
+        assertEquals(expected, GenericRoot.genericRoot(input));
     }
 
-    @Test
-    public void testGenericRootWithNegativeInputs() {
-        for (final var tc : testCases.entrySet()) {
-            assertEquals(tc.getValue(), GenericRoot.genericRoot(-tc.getKey()));
-        }
+    @ParameterizedTest
+    @MethodSource("tcStream")
+    public void testGenericRootWithNegativeInputs(final int input, final int expected) {
+        assertEquals(expected, GenericRoot.genericRoot(-input));
+    }
+
+    private static Stream<Arguments> tcStream() {
+        return Stream.of(Arguments.of(0, 0), Arguments.of(1, 1), Arguments.of(12345, 6), Arguments.of(123, 6), Arguments.of(15937, 7), Arguments.of(222222, 3), Arguments.of(99999, 9));
     }
 }

From be38886d4361a4d8414a16031da27c0e0e62fe41 Mon Sep 17 00:00:00 2001
From: StarDxxx <36352922+StarDxxx@users.noreply.github.com>
Date: Sat, 8 Jun 2024 15:36:42 +0800
Subject: [PATCH 0193/1338] style: enable `OperatorWrap` in checkstyle (#5212)

---
 checkstyle.xml                                   | 2 +-
 src/main/java/com/thealgorithms/ciphers/AES.java | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 5ada9361d03c..4078ffbbf537 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -139,7 +139,7 @@
     <module name="MethodParamPad"/>
     <!-- TODO <module name="NoWhitespaceAfter"/> -->
     <module name="NoWhitespaceBefore"/>
-    <!-- TODO <module name="OperatorWrap"/> -->
+    <module name="OperatorWrap"/>
     <!-- TODO <module name="ParenPad"/> -->
     <module name="TypecastParenPad"/>
     <module name="WhitespaceAfter"/>
diff --git a/src/main/java/com/thealgorithms/ciphers/AES.java b/src/main/java/com/thealgorithms/ciphers/AES.java
index cd04395e1b72..5d614afbe584 100644
--- a/src/main/java/com/thealgorithms/ciphers/AES.java
+++ b/src/main/java/com/thealgorithms/ciphers/AES.java
@@ -2756,8 +2756,8 @@ public static void main(String[] args) {
                     in = input.nextLine();
                     BigInteger encryptionKey = new BigInteger(in, 16);
                     System.out.println(
-                        "The encrypted message is: \n" +
-                        encrypt(plaintext, encryptionKey).toString(16)
+                        "The encrypted message is: \n"
+                        + encrypt(plaintext, encryptionKey).toString(16)
                     );
                 }
                 case 'D', 'd' -> {
@@ -2772,8 +2772,8 @@ public static void main(String[] args) {
                     in = input.nextLine();
                     BigInteger decryptionKey = new BigInteger(in, 16);
                     System.out.println(
-                        "The deciphered message is:\n" +
-                        decrypt(ciphertext, decryptionKey).toString(16)
+                        "The deciphered message is:\n"
+                        + decrypt(ciphertext, decryptionKey).toString(16)
                     );
                 }
                 default -> System.out.println("** End **");

From a81fb32e6cdd739889e115761694d0c11bac7b29 Mon Sep 17 00:00:00 2001
From: StarDxxx <36352922+StarDxxx@users.noreply.github.com>
Date: Sat, 8 Jun 2024 19:37:20 +0800
Subject: [PATCH 0194/1338] style: enable `TypeName` (#5214)

* style: enable `TypeName` in checkstyle

* style: enable `TypeName` in checkstyle

* Update directory

* style: use proper formatting

---------

Co-authored-by: StarDxxx <StarDxxx@users.noreply.github.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 DIRECTORY.md                                  | 26 ++++++++++---------
 checkstyle.xml                                |  2 +-
 pmd-exclude.properties                        |  2 +-
 .../graphs/{A_Star.java => AStar.java}        |  4 +--
 .../graphs/DIJSKSTRAS_ALGORITHM.java          |  4 +--
 ...dlist.java => MergeKSortedLinkedlist.java} |  2 +-
 .../datastructures/lists/README.md            |  2 +-
 ...rixTranspose.java => MatrixTranspose.java} |  4 +--
 .../{countSetBits.java => CountSetBits.java}  |  4 +--
 .../others/RotateMatrixBy90Degrees.java       |  4 +--
 ...ava => SortOrderAgnosticBinarySearch.java} |  4 +--
 ...java => LongestNonRepeativeSubstring.java} |  4 +--
 ...{zigZagPattern.java => ZigZagPattern.java} |  4 +--
 ...mbStairsTest.java => ClimbStairsTest.java} |  2 +-
 .../others/CountSetBitsTest.java              | 17 ++++++++++++
 .../others/countSetBitsTest.java              | 17 ------------
 ...=> SortOrderAgnosticBinarySearchTest.java} |  6 ++---
 ... => LongestNonRepeativeSubstringTest.java} |  6 ++---
 ...atternTest.java => ZigZagPatternTest.java} |  6 ++---
 19 files changed, 61 insertions(+), 59 deletions(-)
 rename src/main/java/com/thealgorithms/datastructures/graphs/{A_Star.java => AStar.java} (99%)
 rename src/main/java/com/thealgorithms/datastructures/lists/{Merge_K_SortedLinkedlist.java => MergeKSortedLinkedlist.java} (96%)
 rename src/main/java/com/thealgorithms/misc/{matrixTranspose.java => MatrixTranspose.java} (96%)
 rename src/main/java/com/thealgorithms/others/{countSetBits.java => CountSetBits.java} (95%)
 rename src/main/java/com/thealgorithms/searches/{sortOrderAgnosticBinarySearch.java => SortOrderAgnosticBinarySearch.java} (90%)
 rename src/main/java/com/thealgorithms/strings/{longestNonRepeativeSubstring.java => LongestNonRepeativeSubstring.java} (93%)
 rename src/main/java/com/thealgorithms/strings/zigZagPattern/{zigZagPattern.java => ZigZagPattern.java} (95%)
 rename src/test/java/com/thealgorithms/dynamicprogramming/{climbStairsTest.java => ClimbStairsTest.java} (95%)
 create mode 100644 src/test/java/com/thealgorithms/others/CountSetBitsTest.java
 delete mode 100644 src/test/java/com/thealgorithms/others/countSetBitsTest.java
 rename src/test/java/com/thealgorithms/searches/{sortOrderAgnosticBinarySearchTest.java => SortOrderAgnosticBinarySearchTest.java} (75%)
 rename src/test/java/com/thealgorithms/strings/{longestNonRepeativeSubstringTest.java => LongestNonRepeativeSubstringTest.java} (64%)
 rename src/test/java/com/thealgorithms/strings/zigZagPattern/{zigZagPatternTest.java => ZigZagPatternTest.java} (67%)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index c8b38bb20343..7c46336f0911 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -18,6 +18,7 @@
             * [ParenthesesGenerator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java)
             * [Permutation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/Permutation.java)
             * [PowerSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/PowerSum.java)
+            * [SubsequenceFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/SubsequenceFinder.java)
             * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
           * bitmanipulation
             * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
@@ -96,7 +97,7 @@
             * dynamicarray
               * [DynamicArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java)
             * graphs
-              * [A Star](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java)
+              * [AStar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java)
               * [BellmanFord](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java)
               * [BipartiteGrapfDFS](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java)
               * [BoruvkaAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithm.java)
@@ -141,7 +142,7 @@
               * [CreateAndDetectLoop](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java)
               * [CursorLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java)
               * [DoublyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java)
-              * [Merge K SortedLinkedlist](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java)
+              * [MergeKSortedLinkedlist](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedlist.java)
               * [MergeSortedArrayList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java)
               * [MergeSortedSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java)
               * [QuickSortLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java)
@@ -376,7 +377,7 @@
             * [ColorContrastRatio](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java)
             * [InverseOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java)
             * [MapReduce](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MapReduce.java)
-            * [matrixTranspose](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/matrixTranspose.java)
+            * [MatrixTranspose](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MatrixTranspose.java)
             * [MedianOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java)
             * [MedianOfRunningArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java)
             * [MedianOfRunningArrayByte](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayByte.java)
@@ -403,7 +404,7 @@
               * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/cn/HammingDistance.java)
             * [Conway](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Conway.java)
             * [CountChar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountChar.java)
-            * [countSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/countSetBits.java)
+            * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountSetBits.java)
             * [CountWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountWords.java)
             * [CRC16](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CRC16.java)
             * [CRC32](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CRC32.java)
@@ -478,7 +479,7 @@
             * [RowColumnWiseSorted2dArrayBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java)
             * [SaddlebackSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java)
             * [SearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java)
-            * [sortOrderAgnosticBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearch.java)
+            * [SortOrderAgnosticBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java)
             * [SquareRootBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java)
             * [TernarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/TernarySearch.java)
             * [UnionFind](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UnionFind.java)
@@ -549,7 +550,7 @@
             * [HorspoolSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/HorspoolSearch.java)
             * [Isomorphic](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Isomorphic.java)
             * [LetterCombinationsOfPhoneNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java)
-            * [longestNonRepeativeSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java)
+            * [LongestNonRepeativeSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java)
             * [LongestPalindromicSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java)
             * [Lower](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Lower.java)
             * [MyAtoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/MyAtoi.java)
@@ -565,7 +566,7 @@
             * [ValidParentheses](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ValidParentheses.java)
             * [WordLadder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/WordLadder.java)
             * zigZagPattern
-              * [zigZagPattern](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java)
+              * [ZigZagPattern](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java)
   * test
     * java
       * com
@@ -580,6 +581,7 @@
             * [ParenthesesGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/ParenthesesGeneratorTest.java)
             * [PermutationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PermutationTest.java)
             * [PowerSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PowerSumTest.java)
+            * [SubsequenceFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/SubsequenceFinderTest.java)
             * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
           * bitmanipulation
             * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
@@ -684,7 +686,7 @@
             * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
           * dynamicprogramming
             * [CatalanNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java)
-            * [climbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/climbStairsTest.java)
+            * [ClimbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java)
             * [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
             * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
             * [KnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
@@ -812,7 +814,7 @@
             * [ConwayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ConwayTest.java)
             * [CountCharTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountCharTest.java)
             * [CountFriendsPairingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountFriendsPairingTest.java)
-            * [countSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/countSetBitsTest.java)
+            * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountSetBitsTest.java)
             * [CountWordsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountWordsTest.java)
             * [CRC16Test](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CRC16Test.java)
             * [CRCAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java)
@@ -848,7 +850,7 @@
             * [RabinKarpAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java)
             * [RecursiveBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java)
             * [RowColumnWiseSorted2dArrayBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java)
-            * [sortOrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearchTest.java)
+            * [SortOrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
             * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
           * sorts
             * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
@@ -896,7 +898,7 @@
             * [HorspoolSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java)
             * [IsomorphicTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/IsomorphicTest.java)
             * [LetterCombinationsOfPhoneNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java)
-            * [longestNonRepeativeSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/longestNonRepeativeSubstringTest.java)
+            * [LongestNonRepeativeSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestNonRepeativeSubstringTest.java)
             * [LowerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LowerTest.java)
             * [MyAtoiTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/MyAtoiTest.java)
             * [PalindromeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PalindromeTest.java)
@@ -910,4 +912,4 @@
             * [ValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java)
             * [WordLadderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/WordLadderTest.java)
             * zigZagPattern
-              * [zigZagPatternTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/zigZagPattern/zigZagPatternTest.java)
+              * [ZigZagPatternTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java)
diff --git a/checkstyle.xml b/checkstyle.xml
index 4078ffbbf537..cb4ee54670ac 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -116,7 +116,7 @@
     <module name="PackageName"/>
     <module name="ParameterName"/>
     <module name="StaticVariableName"/>
-    <!-- TODO <module name="TypeName"/> -->
+    <module name="TypeName"/>
 
     <!-- Checks for imports                              -->
     <!-- See https://checkstyle.org/checks/imports/index.html -->
diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index 400863992ed0..eb199da3a0d3 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -10,7 +10,7 @@ com.thealgorithms.conversions.HexToOct=UselessParentheses
 com.thealgorithms.conversions.IntegerToRoman=UnnecessaryFullyQualifiedName
 com.thealgorithms.datastructures.crdt.LWWElementSet=UselessParentheses
 com.thealgorithms.datastructures.crdt.Pair=UnusedPrivateField
-com.thealgorithms.datastructures.graphs.A_Star=UselessParentheses
+com.thealgorithms.datastructures.graphs.AStar=UselessParentheses
 com.thealgorithms.datastructures.graphs.AdjacencyMatrixGraph=CollapsibleIfStatements,UnnecessaryFullyQualifiedName,UselessParentheses
 com.thealgorithms.datastructures.graphs.BipartiteGrapfDFS=CollapsibleIfStatements
 com.thealgorithms.datastructures.graphs.Kruskal=UselessParentheses
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java b/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java
similarity index 99%
rename from src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
rename to src/main/java/com/thealgorithms/datastructures/graphs/AStar.java
index b1af21eb6ff2..54fb5fba5c1b 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java
@@ -9,8 +9,8 @@
 import java.util.List;
 import java.util.PriorityQueue;
 
-public final class A_Star {
-    private A_Star() {
+public final class AStar {
+    private AStar() {
     }
 
     private static class Graph {
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java b/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
index 8503aa48ec37..419da4a9be73 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
@@ -4,7 +4,7 @@
  */
 package com.thealgorithms.datastructures.graphs;
 
-class dijkstras {
+class Dijkstras {
 
     int k = 9;
 
@@ -67,7 +67,7 @@ public static void main(String[] args) {
             {8, 11, 0, 0, 0, 0, 1, 0, 7},
             {0, 0, 2, 0, 0, 0, 6, 7, 0},
         };
-        dijkstras t = new dijkstras();
+        Dijkstras t = new Dijkstras();
         t.dijkstra(graph, 0);
     } // main
 } // djikstras
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java b/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedlist.java
similarity index 96%
rename from src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java
rename to src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedlist.java
index a714eda18bcd..ece178908e63 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/Merge_K_SortedLinkedlist.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedlist.java
@@ -7,7 +7,7 @@
 /**
  * @author Arun Pandey (https://github.com/pandeyarun709)
  */
-public class Merge_K_SortedLinkedlist {
+public class MergeKSortedLinkedlist {
 
     /**
      * This function merge K sorted LinkedList
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/README.md b/src/main/java/com/thealgorithms/datastructures/lists/README.md
index cfb8221abca6..ea389c0422ce 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/README.md
+++ b/src/main/java/com/thealgorithms/datastructures/lists/README.md
@@ -27,6 +27,6 @@ The `next` variable points to the next node in the data structure and value stor
 3. `CountSinglyLinkedListRecursion.java`: Recursively counts the size of a list.
 4. `CreateAndDetectLoop.java` : Create and detect a loop in a linked list.
 5. `DoublyLinkedList.java` : A modification of singly linked list which has a `prev` pointer to point to the previous node.
-6. `Merge_K_SortedLinkedlist.java` : Merges K sorted linked list with mergesort (mergesort is also the most efficient sorting algorithm for linked list).
+6. `MergeKSortedLinkedlist.java` : Merges K sorted linked list with mergesort (mergesort is also the most efficient sorting algorithm for linked list).
 7. `RandomNode.java` : Selects a random node from given linked list and diplays it.
 8. `SkipList.java` : Data Structure used for storing a sorted list of elements with help of a Linked list hierarchy that connects to subsequences of elements.
diff --git a/src/main/java/com/thealgorithms/misc/matrixTranspose.java b/src/main/java/com/thealgorithms/misc/MatrixTranspose.java
similarity index 96%
rename from src/main/java/com/thealgorithms/misc/matrixTranspose.java
rename to src/main/java/com/thealgorithms/misc/MatrixTranspose.java
index 40634f18b5f6..153cf4e9df99 100644
--- a/src/main/java/com/thealgorithms/misc/matrixTranspose.java
+++ b/src/main/java/com/thealgorithms/misc/MatrixTranspose.java
@@ -18,8 +18,8 @@
  * @version 11.0.9
  * @since 2014-03-31
  */
-public final class matrixTranspose {
-    private matrixTranspose() {
+public final class MatrixTranspose {
+    private MatrixTranspose() {
     }
 
     public static void main(String[] args) {
diff --git a/src/main/java/com/thealgorithms/others/countSetBits.java b/src/main/java/com/thealgorithms/others/CountSetBits.java
similarity index 95%
rename from src/main/java/com/thealgorithms/others/countSetBits.java
rename to src/main/java/com/thealgorithms/others/CountSetBits.java
index 04e0d6f62e6e..b26f745d4cd7 100644
--- a/src/main/java/com/thealgorithms/others/countSetBits.java
+++ b/src/main/java/com/thealgorithms/others/CountSetBits.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.others;
 
-public class countSetBits {
+public class CountSetBits {
 
     /**
      * The below algorithm is called as Brian Kernighan's algorithm
@@ -40,7 +40,7 @@ public class countSetBits {
      * @param num takes Long number whose number of set bit is to be found
      * @return the count of set bits in the binary equivalent
     */
-    public long countsetBits(long num) {
+    public long countSetBits(long num) {
         long cnt = 0;
         while (num > 0) {
             cnt++;
diff --git a/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java b/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
index 2ea3de814d0d..3930ca3e95ff 100644
--- a/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
+++ b/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
@@ -6,8 +6,8 @@
  */
 import java.util.Scanner;
 
-final class Rotate_by_90_degrees {
-    private Rotate_by_90_degrees() {
+final class RotateMatrixBy90Degrees {
+    private RotateMatrixBy90Degrees() {
     }
 
     public static void main(String[] args) {
diff --git a/src/main/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearch.java b/src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java
similarity index 90%
rename from src/main/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearch.java
rename to src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java
index acb9fb5cb3cd..6a2a46c2821f 100644
--- a/src/main/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.searches;
-public final class sortOrderAgnosticBinarySearch {
-    private sortOrderAgnosticBinarySearch() {
+public final class SortOrderAgnosticBinarySearch {
+    private SortOrderAgnosticBinarySearch() {
     }
     public static int find(int[] arr, int key) {
         int start = 0;
diff --git a/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java b/src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java
similarity index 93%
rename from src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java
rename to src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java
index 99154542955f..140e668fc841 100644
--- a/src/main/java/com/thealgorithms/strings/longestNonRepeativeSubstring.java
+++ b/src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java
@@ -2,8 +2,8 @@
 
 import java.util.HashMap;
 
-final class longestNonRepeativeSubstring {
-    private longestNonRepeativeSubstring() {
+final class LongestNonRepeativeSubstring {
+    private LongestNonRepeativeSubstring() {
     }
 
     public static int lengthOfLongestSubstring(String s) {
diff --git a/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java b/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java
similarity index 95%
rename from src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
rename to src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java
index 2dfcf3909b8f..3337f6eeff71 100644
--- a/src/main/java/com/thealgorithms/strings/zigZagPattern/zigZagPattern.java
+++ b/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java
@@ -1,7 +1,7 @@
 package com.thealgorithms.strings.zigZagPattern;
 
-final class zigZagPattern {
-    private zigZagPattern() {
+final class ZigZagPattern {
+    private ZigZagPattern() {
     }
 
     public static String encode(String s, int numRows) {
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/climbStairsTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java
similarity index 95%
rename from src/test/java/com/thealgorithms/dynamicprogramming/climbStairsTest.java
rename to src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java
index 7df3127eec82..1f2de4a11b62 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/climbStairsTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java
@@ -4,7 +4,7 @@
 
 import org.junit.jupiter.api.Test;
 
-public class climbStairsTest {
+public class ClimbStairsTest {
 
     @Test
     void climbStairsTestForTwo() {
diff --git a/src/test/java/com/thealgorithms/others/CountSetBitsTest.java b/src/test/java/com/thealgorithms/others/CountSetBitsTest.java
new file mode 100644
index 000000000000..ab34c6ba7876
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/CountSetBitsTest.java
@@ -0,0 +1,17 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class CountSetBitsTest {
+
+    @Test
+    void testSetBits() {
+        CountSetBits csb = new CountSetBits();
+        assertEquals(1L, csb.countSetBits(16));
+        assertEquals(4, csb.countSetBits(15));
+        assertEquals(5, csb.countSetBits(10000));
+        assertEquals(5, csb.countSetBits(31));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/others/countSetBitsTest.java b/src/test/java/com/thealgorithms/others/countSetBitsTest.java
deleted file mode 100644
index 1429aac8daff..000000000000
--- a/src/test/java/com/thealgorithms/others/countSetBitsTest.java
+++ /dev/null
@@ -1,17 +0,0 @@
-package com.thealgorithms.others;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.api.Test;
-
-public class countSetBitsTest {
-
-    @Test
-    void testSetBits() {
-        countSetBits csb = new countSetBits();
-        assertEquals(1L, csb.countsetBits(16));
-        assertEquals(4, csb.countsetBits(15));
-        assertEquals(5, csb.countsetBits(10000));
-        assertEquals(5, csb.countsetBits(31));
-    }
-}
diff --git a/src/test/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java
similarity index 75%
rename from src/test/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearchTest.java
rename to src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java
index 04ed00ae85b9..e2917733d1d9 100644
--- a/src/test/java/com/thealgorithms/searches/sortOrderAgnosticBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java
@@ -4,13 +4,13 @@
 
 import org.junit.jupiter.api.Test;
 
-public class sortOrderAgnosticBinarySearchTest {
+public class SortOrderAgnosticBinarySearchTest {
 
     @Test
     public void testAscending() {
         int[] arr = {1, 2, 3, 4, 5}; // for ascending order.
         int target = 2;
-        int ans = sortOrderAgnosticBinarySearch.find(arr, target);
+        int ans = SortOrderAgnosticBinarySearch.find(arr, target);
         int excepted = 1;
         assertEquals(excepted, ans);
     }
@@ -19,7 +19,7 @@ public void testAscending() {
     public void testDescending() {
         int[] arr = {5, 4, 3, 2, 1}; // for descending order.
         int target = 2;
-        int ans = sortOrderAgnosticBinarySearch.find(arr, target);
+        int ans = SortOrderAgnosticBinarySearch.find(arr, target);
         int excepted = 3;
         assertEquals(excepted, ans);
     }
diff --git a/src/test/java/com/thealgorithms/strings/longestNonRepeativeSubstringTest.java b/src/test/java/com/thealgorithms/strings/LongestNonRepeativeSubstringTest.java
similarity index 64%
rename from src/test/java/com/thealgorithms/strings/longestNonRepeativeSubstringTest.java
rename to src/test/java/com/thealgorithms/strings/LongestNonRepeativeSubstringTest.java
index 2dce8cf38c05..4bd5ac996719 100644
--- a/src/test/java/com/thealgorithms/strings/longestNonRepeativeSubstringTest.java
+++ b/src/test/java/com/thealgorithms/strings/LongestNonRepeativeSubstringTest.java
@@ -3,13 +3,13 @@
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
-public class longestNonRepeativeSubstringTest {
+public class LongestNonRepeativeSubstringTest {
 
     @Test
     public void palindrome() {
         String input1 = "HelloWorld";
         String input2 = "javaIsAProgrammingLanguage";
-        Assertions.assertEquals(longestNonRepeativeSubstring.lengthOfLongestSubstring(input1), 5);
-        Assertions.assertEquals(longestNonRepeativeSubstring.lengthOfLongestSubstring(input2), 9);
+        Assertions.assertEquals(LongestNonRepeativeSubstring.lengthOfLongestSubstring(input1), 5);
+        Assertions.assertEquals(LongestNonRepeativeSubstring.lengthOfLongestSubstring(input2), 9);
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/zigZagPattern/zigZagPatternTest.java b/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java
similarity index 67%
rename from src/test/java/com/thealgorithms/strings/zigZagPattern/zigZagPatternTest.java
rename to src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java
index 02904ddcf6c3..518bfab80f08 100644
--- a/src/test/java/com/thealgorithms/strings/zigZagPattern/zigZagPatternTest.java
+++ b/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java
@@ -3,13 +3,13 @@
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
-public class zigZagPatternTest {
+public class ZigZagPatternTest {
 
     @Test
     public void palindrome() {
         String input1 = "HelloWorldFromJava";
         String input2 = "javaIsAProgrammingLanguage";
-        Assertions.assertEquals(zigZagPattern.encode(input1, 4), "HooeWrrmalolFJvlda");
-        Assertions.assertEquals(zigZagPattern.encode(input2, 4), "jAaLgasPrmgaaevIrgmnnuaoig");
+        Assertions.assertEquals(ZigZagPattern.encode(input1, 4), "HooeWrrmalolFJvlda");
+        Assertions.assertEquals(ZigZagPattern.encode(input2, 4), "jAaLgasPrmgaaevIrgmnnuaoig");
     }
 }

From 0e8fed0dd63cbee83c6b3e6c7834ae64c3a27d42 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 11 Jun 2024 00:02:21 +0200
Subject: [PATCH 0195/1338] Chore(deps): bump gitpod/workspace-java-21 from
 2024-06-03-17-43-12 to 2024-06-10-10-39-01 (#5218)

Chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2024-06-03-17-43-12 to 2024-06-10-10-39-01.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 82696623f953..6ca2b97e8442 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-06-03-17-43-12
+FROM gitpod/workspace-java-21:2024-06-10-10-39-01
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 3ecd13508a8ebe533afe3486bac66cb3ab54cecb Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 12 Jun 2024 06:15:51 +0000
Subject: [PATCH 0196/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-pmd-plugin from 3.22.0 to 3.23.0 (#5220)

Chore(deps): bump org.apache.maven.plugins:maven-pmd-plugin

Bumps [org.apache.maven.plugins:maven-pmd-plugin](https://github.com/apache/maven-pmd-plugin) from 3.22.0 to 3.23.0.
- [Release notes](https://github.com/apache/maven-pmd-plugin/releases)
- [Commits](https://github.com/apache/maven-pmd-plugin/compare/maven-pmd-plugin-3.22.0...maven-pmd-plugin-3.23.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-pmd-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 6e8c9acf92b0..98771e184caa 100644
--- a/pom.xml
+++ b/pom.xml
@@ -146,7 +146,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-pmd-plugin</artifactId>
-                <version>3.22.0</version>
+                <version>3.23.0</version>
                 <configuration>
                     <printFailingErrors>true</printFailingErrors>
                     <includeTests>true</includeTests>

From f8698674b3785e046cb30ec9aec68fbab7eec195 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 13 Jun 2024 06:37:14 +0200
Subject: [PATCH 0197/1338] style: include `IM_BAD_CHECK_FOR_ODD` (#5213)

---
 spotbugs-exclude.xml                                          | 3 ---
 src/main/java/com/thealgorithms/maths/SimpsonIntegration.java | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index a01e489ba878..8d80528696c0 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -65,9 +65,6 @@
     <Match>
         <Bug pattern="MS_EXPOSE_REP" />
     </Match>
-    <Match>
-        <Bug pattern="IM_BAD_CHECK_FOR_ODD" />
-    </Match>
     <Match>
         <Bug pattern="DM_BOXED_PRIMITIVE_FOR_PARSING" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java b/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java
index 79bc112902c4..1163208a1f83 100644
--- a/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java
+++ b/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java
@@ -63,7 +63,7 @@ public double simpsonsMethod(int n, double h, double a) {
             if (i == 0 || i == data.size() - 1) {
                 integralEvaluation += data.get(i);
                 System.out.println("Multiply f(x" + i + ") by 1");
-            } else if (i % 2 == 1) {
+            } else if (i % 2 != 0) {
                 integralEvaluation += (double) 4 * data.get(i);
                 System.out.println("Multiply f(x" + i + ") by 4");
             } else {

From a2af09cdfb9606c4818bbf98d188de77a6834dcc Mon Sep 17 00:00:00 2001
From: Samuel Facchinello <4256795+samuelfac@users.noreply.github.com>
Date: Thu, 13 Jun 2024 19:25:43 +0200
Subject: [PATCH 0198/1338] style: enable `ParenPad` in checkstyle (#5226)

* enable ParenPad

* style: enable ParenPad in checkstyle

---------

Co-authored-by: Samuel Facchinello <samuel.facchinello@piksel.com>
---
 checkstyle.xml                                            | 2 +-
 .../thealgorithms/datastructures/graphs/BellmanFord.java  | 8 +++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index cb4ee54670ac..b65291b8ffa8 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -140,7 +140,7 @@
     <!-- TODO <module name="NoWhitespaceAfter"/> -->
     <module name="NoWhitespaceBefore"/>
     <module name="OperatorWrap"/>
-    <!-- TODO <module name="ParenPad"/> -->
+    <module name="ParenPad"/>
     <module name="TypecastParenPad"/>
     <module name="WhitespaceAfter"/>
     <!-- TODO <module name="WhitespaceAround"/> -->
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
index 522e19787e8c..47c5f0d0b98e 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
@@ -57,9 +57,11 @@ public static void main(String[] args) {
         obj.go();
     }
 
-    public void go() { // shows distance to all vertices // Interactive run for understanding the
-        try ( // class first time. Assumes source vertex is 0 and
-            Scanner sc = new Scanner(System.in)) {
+    public void go() {
+        // shows distance to all vertices
+        // Interactive run for understanding the
+        // class first time. Assumes source vertex is 0 and
+        try (Scanner sc = new Scanner(System.in)) {
             int i;
             int v;
             int e;

From 31db1af345b0635633d962a944210edaff3d5251 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 13 Jun 2024 19:27:49 +0200
Subject: [PATCH 0199/1338] style: include `SUI_CONTAINS_BEFORE_ADD` (#5216)

---
 spotbugs-exclude.xml                                           | 3 ---
 .../datastructures/graphs/ConnectedComponent.java              | 3 +--
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 8d80528696c0..0a5354382a4f 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -222,9 +222,6 @@
     <Match>
         <Bug pattern="IMC_IMMATURE_CLASS_BAD_SERIALVERSIONUID" />
     </Match>
-    <Match>
-        <Bug pattern="SUI_CONTAINS_BEFORE_ADD" />
-    </Match>
     <Match>
         <Bug pattern="DRE_DECLARED_RUNTIME_EXCEPTION" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java b/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
index d2b76e8e06b1..520a1681774a 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java
@@ -81,8 +81,7 @@ public int countGraphs() {
         Set<Node> markedNodes = new HashSet<Node>();
 
         for (Node n : nodeList) {
-            if (!markedNodes.contains(n)) {
-                markedNodes.add(n);
+            if (markedNodes.add(n)) {
                 markedNodes.addAll(depthFirstSearch(n, new ArrayList<Node>()));
                 count++;
             }

From 51fcc6634505ddc36576b6e752897778faa8fcc9 Mon Sep 17 00:00:00 2001
From: Samuel Facchinello <4256795+samuelfac@users.noreply.github.com>
Date: Thu, 13 Jun 2024 19:40:12 +0200
Subject: [PATCH 0200/1338] refactor: redesign
 `LetterCombinationsOfPhoneNumber` (#5221)

* Refactor

* fix clang

* fix clang

* fix clang tests

* fix pattern

* add test case null

* Update src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* rename MAP_OF_CHARS to KEYPAD

* fix clang

* remove main

* add tests

* feat: throw for wrong inputs

* change keypad to list

* Update src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* fix with number 1 (empty value), and add tests

* style: avoid concatenation while populating `KEYPAD`

* change to assertEquals

---------

Co-authored-by: Samuel Facchinello <samuel.facchinello@piksel.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../LetterCombinationsOfPhoneNumber.java      | 80 +++++++++++--------
 .../LetterCombinationsOfPhoneNumberTest.java  | 58 ++++++--------
 2 files changed, 71 insertions(+), 67 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java b/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java
index 2e3ee25fb6ea..38c6bc13fa2a 100644
--- a/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java
+++ b/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java
@@ -5,49 +5,61 @@
 import java.util.List;
 
 public final class LetterCombinationsOfPhoneNumber {
+
+    private static final char EMPTY = '\0';
+
+    // Mapping of numbers to corresponding letters on a phone keypad
+    private static final String[] KEYPAD = new String[] {" ", String.valueOf(EMPTY), "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
+
     private LetterCombinationsOfPhoneNumber() {
     }
 
-    static Character[][] numberToCharMap;
-
-    protected static List<String> printWords(int[] numbers, int len, int numIndex, String s) {
-        if (len == numIndex) {
-            return new ArrayList<>(Collections.singleton(s));
+    /**
+     * Generates a list of all possible letter combinations that the provided
+     * array of numbers could represent on a phone keypad.
+     *
+     * @param numbers an array of integers representing the phone numbers
+     * @return a list of possible letter combinations
+     */
+    public static List<String> getCombinations(int[] numbers) {
+        if (numbers == null) {
+            return List.of("");
         }
+        return generateCombinations(numbers, 0, new StringBuilder());
+    }
 
-        List<String> stringList = new ArrayList<>();
+    /**
+     * Recursive method to generate combinations of letters from the phone keypad.
+     *
+     * @param numbers the input array of phone numbers
+     * @param index   the current index in the numbers array being processed
+     * @param current a StringBuilder holding the current combination of letters
+     * @return a list of letter combinations formed from the given numbers
+     */
+    private static List<String> generateCombinations(int[] numbers, int index, StringBuilder current) {
+        // Base case: if we've processed all numbers, return the current combination
+        if (index == numbers.length) {
+            return new ArrayList<>(Collections.singletonList(current.toString()));
+        }
 
-        for (int i = 0; i < numberToCharMap[numbers[numIndex]].length; i++) {
-            String sCopy = String.copyValueOf(s.toCharArray());
-            sCopy = sCopy.concat(numberToCharMap[numbers[numIndex]][i].toString());
-            stringList.addAll(printWords(numbers, len, numIndex + 1, sCopy));
+        final var number = numbers[index];
+        if (number < 0 || number > 9) {
+            throw new IllegalArgumentException("Input numbers must in the range [0, 9]");
         }
-        return stringList;
-    }
 
-    private static void printWords(int[] numbers) {
-        generateNumberToCharMap();
-        List<String> stringList = printWords(numbers, numbers.length, 0, "");
-        stringList.stream().forEach(System.out::println);
-    }
+        List<String> combinations = new ArrayList<>();
 
-    protected static void generateNumberToCharMap() {
-        numberToCharMap = new Character[10][5];
-        numberToCharMap[0] = new Character[] {'\0'};
-        numberToCharMap[1] = new Character[] {'\0'};
-        numberToCharMap[2] = new Character[] {'a', 'b', 'c'};
-        numberToCharMap[3] = new Character[] {'d', 'e', 'f'};
-        numberToCharMap[4] = new Character[] {'g', 'h', 'i'};
-        numberToCharMap[5] = new Character[] {'j', 'k', 'l'};
-        numberToCharMap[6] = new Character[] {'m', 'n', 'o'};
-        numberToCharMap[7] = new Character[] {'p', 'q', 'r', 's'};
-        numberToCharMap[8] = new Character[] {'t', 'u', 'v'};
-        numberToCharMap[9] = new Character[] {'w', 'x', 'y', 'z'};
-    }
+        // Iterate over each letter and recurse to generate further combinations
+        for (char letter : KEYPAD[number].toCharArray()) {
+            if (letter != EMPTY) {
+                current.append(letter);
+            }
+            combinations.addAll(generateCombinations(numbers, index + 1, current));
+            if (letter != EMPTY) {
+                current.deleteCharAt(current.length() - 1); // Backtrack by removing the last appended letter
+            }
+        }
 
-    // Driver code
-    public static void main(String[] args) {
-        int[] number = {2, 3, 4};
-        printWords(number);
+        return combinations;
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java b/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java
index 4ffbddcb44a8..dcdb7d5b3392 100644
--- a/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java
+++ b/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java
@@ -1,45 +1,37 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import java.util.Arrays;
 import java.util.List;
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class LetterCombinationsOfPhoneNumberTest {
 
-    @Test
-    public void letterCombinationsOfPhoneNumber() {
-        LetterCombinationsOfPhoneNumber.generateNumberToCharMap();
-
-        // ** Test 1 **
-        // Input: digits = ""
-        // Output: []
-        int[] numbers1 = {};
-        List<String> output1 = Arrays.asList("");
-        assertTrue(LetterCombinationsOfPhoneNumber.printWords(numbers1, numbers1.length, 0, "").equals(output1));
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testLetterCombinationsOfPhoneNumber(int[] numbers, List<String> expectedOutput) {
+        assertEquals(expectedOutput, LetterCombinationsOfPhoneNumber.getCombinations(numbers));
+    }
 
-        // ** Test 2 **
-        // Input: digits = "2"
-        // Output: ["a","b","c"]
-        int[] numbers2 = {2};
-        List<String> output2 = Arrays.asList("a", "b", "c");
-        assertTrue(LetterCombinationsOfPhoneNumber.printWords(numbers2, numbers2.length, 0, "").equals(output2));
+    @ParameterizedTest
+    @MethodSource("wrongInputs")
+    void throwsForWrongInput(int[] numbers) {
+        assertThrows(IllegalArgumentException.class, () -> LetterCombinationsOfPhoneNumber.getCombinations(numbers));
+    }
 
-        // ** Test 3 **
-        // Input: digits = "23"
-        // Output: ["ad","ae","af","bd","be","bf","cd","ce","cf"]
-        int[] numbers3 = {2, 3};
-        List<String> output3 = Arrays.asList("ad", "ae", "af", "bd", "be", "bf", "cd", "ce", "cf");
-        assertTrue(LetterCombinationsOfPhoneNumber.printWords(numbers3, numbers3.length, 0, "").equals(output3));
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(null, List.of("")), Arguments.of(new int[] {}, List.of("")), Arguments.of(new int[] {2}, List.of("a", "b", "c")), Arguments.of(new int[] {2, 3}, List.of("ad", "ae", "af", "bd", "be", "bf", "cd", "ce", "cf")),
+            Arguments.of(new int[] {2, 3, 4}, List.of("adg", "adh", "adi", "aeg", "aeh", "aei", "afg", "afh", "afi", "bdg", "bdh", "bdi", "beg", "beh", "bei", "bfg", "bfh", "bfi", "cdg", "cdh", "cdi", "ceg", "ceh", "cei", "cfg", "cfh", "cfi")),
+            Arguments.of(new int[] {3, 3}, List.of("dd", "de", "df", "ed", "ee", "ef", "fd", "fe", "ff")), Arguments.of(new int[] {8, 4}, List.of("tg", "th", "ti", "ug", "uh", "ui", "vg", "vh", "vi")), Arguments.of(new int[] {2, 0}, List.of("a ", "b ", "c ")),
+            Arguments.of(new int[] {9, 2}, List.of("wa", "wb", "wc", "xa", "xb", "xc", "ya", "yb", "yc", "za", "zb", "zc")), Arguments.of(new int[] {0}, List.of(" ")), Arguments.of(new int[] {1}, List.of("")), Arguments.of(new int[] {2}, List.of("a", "b", "c")),
+            Arguments.of(new int[] {1, 2, 0, 4}, List.of("a g", "a h", "a i", "b g", "b h", "b i", "c g", "c h", "c i")));
+    }
 
-        // ** Test 4 **
-        // Input: digits = "234"
-        // Output: ["adg", "adh", "adi", "aeg", "aeh", "aei", "afg", "afh", "afi",
-        // "bdg", "bdh", "bdi", "beg", "beh", "bei", "bfg", "bfh", "bfi", "cdg", "cdh",
-        // "cdi", "ceg", "ceh", "cei", "cfg", "cfh", "cfi"]
-        int[] numbers4 = {2, 3, 4};
-        List<String> output4 = Arrays.asList("adg", "adh", "adi", "aeg", "aeh", "aei", "afg", "afh", "afi", "bdg", "bdh", "bdi", "beg", "beh", "bei", "bfg", "bfh", "bfi", "cdg", "cdh", "cdi", "ceg", "ceh", "cei", "cfg", "cfh", "cfi");
-        assertTrue(LetterCombinationsOfPhoneNumber.printWords(numbers4, numbers4.length, 0, "").equals(output4));
+    private static Stream<Arguments> wrongInputs() {
+        return Stream.of(Arguments.of(new int[] {-1}), Arguments.of(new int[] {10}), Arguments.of(new int[] {2, 2, -1, 0}), Arguments.of(new int[] {0, 0, 0, 10}));
     }
 }

From 87b17e05714d011fee82b35f11833bf12ec175cb Mon Sep 17 00:00:00 2001
From: Samuel Facchinello <4256795+samuelfac@users.noreply.github.com>
Date: Thu, 13 Jun 2024 21:00:16 +0200
Subject: [PATCH 0201/1338] style: enable `NeedBraces` in checkstyle (#5227)

* enable style NeedBraces

* style: enable NeedBraces in checkstyle

---------

Co-authored-by: Samuel Facchinello <samuel.facchinello@piksel.com>
---
 checkstyle.xml                                |   2 +-
 .../backtracking/Combination.java             |   4 +-
 .../thealgorithms/backtracking/MColoring.java |   4 +-
 .../backtracking/WordSearch.java              |   8 +-
 .../com/thealgorithms/ciphers/Blowfish.java   |  16 ++-
 .../ciphers/a5/A5KeyStreamGenerator.java      |   4 +-
 .../ciphers/a5/CompositeLFSR.java             |   4 +-
 .../buffers/CircularBuffer.java               |  12 +-
 .../datastructures/graphs/Kosaraju.java       |   8 +-
 .../graphs/TarjansAlgorithm.java              |   4 +-
 .../hashmap/hashing/HashMap.java              |   8 +-
 .../hashmap/hashing/HashMapCuckooHashing.java |   8 +-
 .../datastructures/heaps/FibonacciHeap.java   |   4 +-
 .../datastructures/heaps/LeftistHeap.java     |  16 ++-
 .../datastructures/heaps/MaxHeap.java         |   4 +-
 .../datastructures/heaps/MinHeap.java         |   4 +-
 .../datastructures/queues/CircularQueue.java  |   3 +-
 .../datastructures/queues/LinkedQueue.java    |  16 ++-
 .../datastructures/queues/PriorityQueues.java |   8 +-
 .../datastructures/trees/AVLSimple.java       |  30 +++--
 .../trees/InorderTraversal.java               |   4 +-
 .../datastructures/trees/KDTree.java          | 113 +++++++++++++-----
 .../datastructures/trees/LazySegmentTree.java |  40 +++++--
 .../trees/PreOrderTraversal.java              |  12 +-
 .../datastructures/trees/SameTreesCheck.java  |  12 +-
 .../dynamicprogramming/KadaneAlgorithm.java   |   4 +-
 .../OptimalJobScheduling.java                 |  20 ++--
 .../dynamicprogramming/SubsetCount.java       |  16 ++-
 .../dynamicprogramming/Tribonacci.java        |   8 +-
 .../thealgorithms/geometry/GrahamScan.java    |  42 ++++---
 .../com/thealgorithms/io/BufferedReader.java  |  30 +++--
 .../com/thealgorithms/maths/AliquotSum.java   |   8 +-
 .../maths/AutomorphicNumber.java              |  12 +-
 .../thealgorithms/maths/HarshadNumber.java    |   8 +-
 .../thealgorithms/maths/KaprekarNumbers.java  |   8 +-
 .../maths/MillerRabinPrimalityCheck.java      |  37 ++++--
 .../thealgorithms/maths/PascalTriangle.java   |   7 +-
 .../thealgorithms/maths/PerfectNumber.java    |  12 +-
 .../maths/SumWithoutArithmeticOperators.java  |   4 +-
 .../java/com/thealgorithms/others/CRC16.java  |   4 +-
 ...imumSumOfDistinctSubarraysWithLengthK.java |   4 +-
 .../scheduling/RRScheduling.java              |   4 +-
 .../searches/BinarySearch2dArray.java         |  32 +++--
 .../com/thealgorithms/searches/KMPSearch.java |   5 +-
 .../searches/OrderAgnosticBinarySearch.java   |  23 ++--
 .../thealgorithms/searches/QuickSelect.java   |   4 +-
 .../searches/RabinKarpAlgorithm.java          |  12 +-
 .../searches/RecursiveBinarySearch.java       |   5 +-
 .../sorts/DualPivotQuickSort.java             |  12 +-
 .../thealgorithms/sorts/InsertionSort.java    |  11 +-
 .../com/thealgorithms/sorts/LinkListSort.java |  44 ++++---
 .../thealgorithms/sorts/PigeonholeSort.java   |   4 +-
 .../sorts/SortUtilsRandomGenerator.java       |   4 +-
 .../com/thealgorithms/sorts/StrandSort.java   |   9 +-
 .../thealgorithms/sorts/TopologicalSort.java  |   4 +-
 .../stacks/NextSmallerElement.java            |   4 +-
 .../thealgorithms/stacks/PostfixToInfix.java  |  24 +++-
 .../com/thealgorithms/strings/Anagrams.java   |   4 +-
 .../strings/LongestNonRepeativeSubstring.java |  25 ++--
 .../com/thealgorithms/strings/MyAtoi.java     |   4 +-
 .../com/thealgorithms/strings/Pangram.java    |   7 +-
 .../strings/ValidParentheses.java             |  12 +-
 .../strings/zigZagPattern/ZigZagPattern.java  |  10 +-
 .../buffers/CircularBufferTest.java           |  32 +++--
 .../queues/LinkedQueueTest.java               |   8 +-
 .../trees/LazySegmentTreeTest.java            |   3 +-
 .../thealgorithms/io/BufferedReaderTest.java  |   4 +-
 .../misc/MedianOfRunningArrayTest.java        |   4 +-
 68 files changed, 627 insertions(+), 259 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index b65291b8ffa8..48c8a4f1f377 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -155,7 +155,7 @@
     <!-- TODO <module name="AvoidNestedBlocks"/> -->
     <!-- TODO <module name="EmptyBlock"/> -->
     <!-- TODO <module name="LeftCurly"/> -->
-    <!-- TODO <module name="NeedBraces"/> -->
+    <module name="NeedBraces"/>
     <!-- TODO <module name="RightCurly"/> -->
 
     <!-- Checks for common coding problems               -->
diff --git a/src/main/java/com/thealgorithms/backtracking/Combination.java b/src/main/java/com/thealgorithms/backtracking/Combination.java
index 80c11ce737fa..bf2a672a0ef8 100644
--- a/src/main/java/com/thealgorithms/backtracking/Combination.java
+++ b/src/main/java/com/thealgorithms/backtracking/Combination.java
@@ -43,7 +43,9 @@ public static <T> List<TreeSet<T>> combination(T[] arr, int n) {
      * @param <T> the type of elements in the array.
      */
     private static <T> void backtracking(T[] arr, int index, TreeSet<T> currSet, List<TreeSet<T>> result) {
-        if (index + length - currSet.size() > arr.length) return;
+        if (index + length - currSet.size() > arr.length) {
+            return;
+        }
         if (length - 1 == currSet.size()) {
             for (int i = index; i < arr.length; i++) {
                 currSet.add(arr[i]);
diff --git a/src/main/java/com/thealgorithms/backtracking/MColoring.java b/src/main/java/com/thealgorithms/backtracking/MColoring.java
index 20c42e59e8a1..f069e46cc627 100644
--- a/src/main/java/com/thealgorithms/backtracking/MColoring.java
+++ b/src/main/java/com/thealgorithms/backtracking/MColoring.java
@@ -59,7 +59,9 @@ static int possiblePaint(ArrayList<Node> nodes, int n, int m) {
                     // If number of colors used exceeds m,
                     // return 0
                     maxColors = Math.max(maxColors, Math.max(nodes.get(top).color, nodes.get(it).color));
-                    if (maxColors > m) return 0;
+                    if (maxColors > m) {
+                        return 0;
+                    }
 
                     // If the adjacent node is not visited,
                     // mark it visited and push it in queue
diff --git a/src/main/java/com/thealgorithms/backtracking/WordSearch.java b/src/main/java/com/thealgorithms/backtracking/WordSearch.java
index 4ab81bfd7d67..f3a5b0433727 100644
--- a/src/main/java/com/thealgorithms/backtracking/WordSearch.java
+++ b/src/main/java/com/thealgorithms/backtracking/WordSearch.java
@@ -51,7 +51,9 @@ private boolean doDFS(int x, int y, int nextIdx) {
             int yi = y + dy[i];
             if (isValid(xi, yi) && board[xi][yi] == word.charAt(nextIdx) && !visited[xi][yi]) {
                 boolean exists = doDFS(xi, yi, nextIdx + 1);
-                if (exists) return true;
+                if (exists) {
+                    return true;
+                }
             }
         }
         visited[x][y] = false;
@@ -66,7 +68,9 @@ public boolean exist(char[][] board, String word) {
                 if (board[i][j] == word.charAt(0)) {
                     visited = new boolean[board.length][board[0].length];
                     boolean exists = doDFS(i, j, 1);
-                    if (exists) return true;
+                    if (exists) {
+                        return true;
+                    }
                 }
             }
         }
diff --git a/src/main/java/com/thealgorithms/ciphers/Blowfish.java b/src/main/java/com/thealgorithms/ciphers/Blowfish.java
index a8fa6fc56088..f6a0a3753e9b 100644
--- a/src/main/java/com/thealgorithms/ciphers/Blowfish.java
+++ b/src/main/java/com/thealgorithms/ciphers/Blowfish.java
@@ -1104,7 +1104,9 @@ private String hexToBin(String hex) {
     private String binToHex(String binary) {
         long num = Long.parseUnsignedLong(binary, 2);
         String hex = Long.toHexString(num);
-        while (hex.length() < (binary.length() / 4)) hex = "0" + hex;
+        while (hex.length() < (binary.length() / 4)) {
+            hex = "0" + hex;
+        }
 
         return hex;
     }
@@ -1120,7 +1122,9 @@ private String xor(String a, String b) {
         a = hexToBin(a);
         b = hexToBin(b);
         String ans = "";
-        for (int i = 0; i < a.length(); i++) ans += (char) (((a.charAt(i) - '0') ^ (b.charAt(i) - '0')) + '0');
+        for (int i = 0; i < a.length(); i++) {
+            ans += (char) (((a.charAt(i) - '0') ^ (b.charAt(i) - '0')) + '0');
+        }
         ans = binToHex(ans);
         return ans;
     }
@@ -1202,7 +1206,9 @@ String encrypt(String plainText, String key) {
         // generating key
         keyGenerate(key);
 
-        for (int i = 0; i < 16; i++) plainText = round(i, plainText);
+        for (int i = 0; i < 16; i++) {
+            plainText = round(i, plainText);
+        }
 
         // postprocessing
         String right = plainText.substring(0, 8);
@@ -1224,7 +1230,9 @@ String decrypt(String cipherText, String key) {
         // generating key
         keyGenerate(key);
 
-        for (int i = 17; i > 1; i--) cipherText = round(i, cipherText);
+        for (int i = 17; i > 1; i--) {
+            cipherText = round(i, cipherText);
+        }
 
         // postprocessing
         String right = cipherText.substring(0, 8);
diff --git a/src/main/java/com/thealgorithms/ciphers/a5/A5KeyStreamGenerator.java b/src/main/java/com/thealgorithms/ciphers/a5/A5KeyStreamGenerator.java
index 2e92498056ae..0b17a685bc57 100644
--- a/src/main/java/com/thealgorithms/ciphers/a5/A5KeyStreamGenerator.java
+++ b/src/main/java/com/thealgorithms/ciphers/a5/A5KeyStreamGenerator.java
@@ -31,7 +31,9 @@ public void reInitialize() {
     }
 
     public BitSet getNextKeyStream() {
-        for (int cycle = 1; cycle <= INITIAL_CLOCKING_CYCLES; ++cycle) this.clock();
+        for (int cycle = 1; cycle <= INITIAL_CLOCKING_CYCLES; ++cycle) {
+            this.clock();
+        }
 
         BitSet result = new BitSet(KEY_STREAM_LENGTH);
         for (int cycle = 1; cycle <= KEY_STREAM_LENGTH; ++cycle) {
diff --git a/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java b/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java
index 3cac558237c2..f96946c39490 100644
--- a/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java
+++ b/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java
@@ -19,7 +19,9 @@ public boolean clock() {
         boolean result = false;
         for (var register : registers) {
             result ^= register.getLastBit();
-            if (register.getClockBit() == majorityBit) register.clock();
+            if (register.getClockBit() == majorityBit) {
+                register.clock();
+            }
         }
         return result;
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java b/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
index 63295b83abe6..15e9a0956226 100644
--- a/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
+++ b/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
@@ -24,7 +24,9 @@ public boolean isFull() {
     }
 
     public Item get() {
-        if (isEmpty()) return null;
+        if (isEmpty()) {
+            return null;
+        }
 
         Item item = buffer[getPointer.getAndIncrement()];
         size.decrementAndGet();
@@ -32,7 +34,9 @@ public Item get() {
     }
 
     public boolean put(Item item) {
-        if (isFull()) return false;
+        if (isFull()) {
+            return false;
+        }
 
         buffer[putPointer.getAndIncrement()] = item;
         size.incrementAndGet();
@@ -49,7 +53,9 @@ private static class CircularPointer {
         }
 
         public int getAndIncrement() {
-            if (pointer == max) pointer = 0;
+            if (pointer == max) {
+                pointer = 0;
+            }
             int tmp = pointer;
             pointer++;
             return tmp;
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java b/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java
index c24046f510af..7c0c0b2bee78 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java
@@ -127,7 +127,9 @@ public void findStronglyConnectedComponents(int v, List<List<Integer>> transpose
     private void dfs(int node, int[] vis, List<List<Integer>> list) {
         vis[node] = 1;
         for (Integer neighbour : list.get(node)) {
-            if (vis[neighbour] == 0) dfs(neighbour, vis, list);
+            if (vis[neighbour] == 0) {
+                dfs(neighbour, vis, list);
+            }
         }
         stack.push(node);
     }
@@ -136,7 +138,9 @@ private void dfs(int node, int[] vis, List<List<Integer>> list) {
     private void dfs2(int node, int[] vis, List<List<Integer>> list) {
         vis[node] = 1;
         for (Integer neighbour : list.get(node)) {
-            if (vis[neighbour] == 0) dfs2(neighbour, vis, list);
+            if (vis[neighbour] == 0) {
+                dfs2(neighbour, vis, list);
+            }
         }
         scc.add(node);
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
index 987e73a2a5d5..336e375f7d4e 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
@@ -82,7 +82,9 @@ public List<List<Integer>> stronglyConnectedComponents(int v, List<List<Integer>
         Stack<Integer> st = new Stack<Integer>();
 
         for (int i = 0; i < v; i++) {
-            if (insertionTime[i] == -1) stronglyConnCompsUtil(i, lowTime, insertionTime, isInStack, st, graph);
+            if (insertionTime[i] == -1) {
+                stronglyConnCompsUtil(i, lowTime, insertionTime, isInStack, st, graph);
+            }
         }
 
         return sccList;
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
index ad273deaf4f0..e0b394b12bf6 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
@@ -68,10 +68,14 @@ private Node findEnd(Node n) {
         public Node findKey(int key) {
             if (!isEmpty()) {
                 Node temp = first;
-                if (temp.getKey() == key) return temp;
+                if (temp.getKey() == key) {
+                    return temp;
+                }
 
                 while ((temp = temp.getNext()) != null) {
-                    if (temp.getKey() == key) return temp;
+                    if (temp.getKey() == key) {
+                        return temp;
+                    }
                 }
             }
             return null;
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
index b48502b51d08..a67968d7e659 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
@@ -188,12 +188,14 @@ public int findKeyInTable(int key) {
             throw new IllegalArgumentException("Table is empty");
         }
 
-        if (Objects.equals(buckets[hash], wrappedInt)) return hash;
+        if (Objects.equals(buckets[hash], wrappedInt)) {
+            return hash;
+        }
 
         hash = hashFunction2(key);
-        if (!Objects.equals(buckets[hash], wrappedInt))
+        if (!Objects.equals(buckets[hash], wrappedInt)) {
             throw new IllegalArgumentException("Key " + key + " not found in table");
-        else {
+        } else {
             return hash;
         }
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
index 4aa7db1956ea..4734483b518b 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
@@ -231,7 +231,9 @@ private void updateMin(HeapNode posMin) {
     private void cascadingCuts(HeapNode curr) {
         if (!curr.isMarked()) { // stop the recursion
             curr.mark();
-            if (!curr.isRoot()) this.markedHeapNoodesCounter++;
+            if (!curr.isRoot()) {
+                this.markedHeapNoodesCounter++;
+            }
         } else {
             if (curr.isRoot()) {
                 return;
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
index 59cb9dfab700..ca18673c6724 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
@@ -56,9 +56,13 @@ public void merge(LeftistHeap h1) {
 
     // Function merge with two Nodes a and b
     public Node merge(Node a, Node b) {
-        if (a == null) return b;
+        if (a == null) {
+            return b;
+        }
 
-        if (b == null) return a;
+        if (b == null) {
+            return a;
+        }
 
         // Violates leftist property, so must do a swap
         if (a.element > b.element) {
@@ -93,7 +97,9 @@ public void insert(int a) {
     // Returns and removes the minimum element in the heap
     public int extractMin() {
         // If is empty return -1
-        if (isEmpty()) return -1;
+        if (isEmpty()) {
+            return -1;
+        }
 
         int min = root.element;
         root = merge(root.left, root.right);
@@ -109,7 +115,9 @@ public ArrayList<Integer> inOrder() {
 
     // Auxiliary function for in_order
     private void inOrderAux(Node n, ArrayList<Integer> lst) {
-        if (n == null) return;
+        if (n == null) {
+            return;
+        }
         inOrderAux(n.left, lst);
         lst.add(n.element);
         inOrderAux(n.right, lst);
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
index 9a584da0411c..067aae738914 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
@@ -98,11 +98,13 @@ public final void insertElement(HeapElement element) {
 
     @Override
     public void deleteElement(int elementIndex) {
-        if (maxHeap.isEmpty()) try {
+        if (maxHeap.isEmpty()) {
+            try {
                 throw new EmptyHeapException("Attempt to delete an element from an empty heap");
             } catch (EmptyHeapException e) {
                 e.printStackTrace();
             }
+        }
         if ((elementIndex > maxHeap.size()) || (elementIndex <= 0)) {
             throw new IndexOutOfBoundsException("Index out of heap range");
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
index f7ff0ec5a73d..6e972205acfe 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
@@ -92,11 +92,13 @@ public final void insertElement(HeapElement element) {
 
     @Override
     public void deleteElement(int elementIndex) {
-        if (minHeap.isEmpty()) try {
+        if (minHeap.isEmpty()) {
+            try {
                 throw new EmptyHeapException("Attempt to delete an element from an empty heap");
             } catch (EmptyHeapException e) {
                 e.printStackTrace();
             }
+        }
         if ((elementIndex > minHeap.size()) || (elementIndex <= 0)) {
             throw new IndexOutOfBoundsException("Index out of heap range");
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
index cd3761bdcf75..48d9ffe9a42a 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
@@ -23,8 +23,9 @@ public boolean isEmpty() {
     public boolean isFull() {
         if (topOfQueue + 1 == beginningOfQueue) {
             return true;
-        } else
+        } else {
             return topOfQueue == size - 1 && beginningOfQueue == 0;
+        }
     }
 
     public void enQueue(int value) {
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
index 171f24e09396..5fba2ff6a69c 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
@@ -125,9 +125,13 @@ public T peekRear() {
      */
 
     public T peek(int pos) {
-        if (pos > size) throw new IndexOutOfBoundsException("Position %s out of range!".formatted(pos));
+        if (pos > size) {
+            throw new IndexOutOfBoundsException("Position %s out of range!".formatted(pos));
+        }
         Node<T> node = front;
-        while (pos-- > 0) node = node.next;
+        while (pos-- > 0) {
+            node = node.next;
+        }
         return node.data;
     }
 
@@ -170,14 +174,18 @@ public int size() {
      * Clear all nodes in queue
      */
     public void clear() {
-        while (size > 0) dequeue();
+        while (size > 0) {
+            dequeue();
+        }
     }
 
     @Override
     public String toString() {
         StringJoiner join = new StringJoiner(", "); // separator of ', '
         Node<T> travel = front;
-        while ((travel = travel.next) != null) join.add(String.valueOf(travel.data));
+        while ((travel = travel.next) != null) {
+            join.add(String.valueOf(travel.data));
+        }
         return '[' + join.toString() + ']';
     }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java b/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java
index 16a0c1673886..a5ca48670f2c 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java
@@ -87,9 +87,13 @@ private void sink(int pos) {
         while (2 * pos <= nItems) {
             int current = 2 * pos; // Jump to the positon of child node
             // Compare both the children for the greater one
-            if (current < nItems && queueArray[current] < queueArray[current + 1]) current++;
+            if (current < nItems && queueArray[current] < queueArray[current + 1]) {
+                current++;
+            }
             // If the parent node is greater, sink operation is complete. Break the loop
-            if (queueArray[pos] >= queueArray[current]) break;
+            if (queueArray[pos] >= queueArray[current]) {
+                break;
+            }
 
             // If not exchange the value of parent with child
             int temp = queueArray[pos];
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java b/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java
index 052da616fe8e..e0309122cc12 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java
@@ -60,9 +60,13 @@ private Node insert(Node node, int item) {
         node.height = Math.max(height(node.left), height(node.right)) + 1;
         int bf = bf(node);
         // LL case
-        if (bf > 1 && item < node.left.data) return rightRotate(node);
+        if (bf > 1 && item < node.left.data) {
+            return rightRotate(node);
+        }
         // RR case
-        if (bf < -1 && item > node.right.data) return leftRotate(node);
+        if (bf < -1 && item > node.right.data) {
+            return leftRotate(node);
+        }
         // RL case
         if (bf < -1 && item < node.right.data) {
             node.right = rightRotate(node.right);
@@ -84,18 +88,24 @@ public void display() {
 
     private void display(Node node) {
         String str = "";
-        if (node.left != null)
+        if (node.left != null) {
             str += node.left.data + "=>";
-        else
+        } else {
             str += "END=>";
+        }
         str += node.data + "";
-        if (node.right != null)
+        if (node.right != null) {
             str += "<=" + node.right.data;
-        else
+        } else {
             str += "<=END";
+        }
         System.out.println(str);
-        if (node.left != null) display(node.left);
-        if (node.right != null) display(node.right);
+        if (node.left != null) {
+            display(node.left);
+        }
+        if (node.right != null) {
+            display(node.right);
+        }
     }
 
     private int height(Node node) {
@@ -106,7 +116,9 @@ private int height(Node node) {
     }
 
     private int bf(Node node) {
-        if (node == null) return 0;
+        if (node == null) {
+            return 0;
+        }
         return height(node.left) - height(node.right);
     }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java
index 3bae17ed1bb8..5a001ff9ab9f 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java
@@ -36,7 +36,9 @@ public static List<Integer> recursiveInorder(BinaryTree.Node root) {
 
     public static List<Integer> iterativeInorder(BinaryTree.Node root) {
         List<Integer> result = new ArrayList<>();
-        if (root == null) return result;
+        if (root == null) {
+            return result;
+        }
 
         Deque<BinaryTree.Node> stack = new ArrayDeque<>();
         while (!stack.isEmpty() || root != null) {
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java b/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
index e5528c392bb8..5190e82f74ef 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java
@@ -34,10 +34,15 @@ public class KDTree {
      * @param points Array of initial points
      */
     KDTree(Point[] points) {
-        if (points.length == 0) throw new IllegalArgumentException("Points array cannot be empty");
+        if (points.length == 0) {
+            throw new IllegalArgumentException("Points array cannot be empty");
+        }
         this.k = points[0].getDimension();
-        for (Point point : points)
-            if (point.getDimension() != k) throw new IllegalArgumentException("Points must have the same dimension");
+        for (Point point : points) {
+            if (point.getDimension() != k) {
+                throw new IllegalArgumentException("Points must have the same dimension");
+            }
+        }
         this.root = build(points, 0);
     }
 
@@ -48,11 +53,16 @@ public class KDTree {
      *
      */
     KDTree(int[][] pointsCoordinates) {
-        if (pointsCoordinates.length == 0) throw new IllegalArgumentException("Points array cannot be empty");
+        if (pointsCoordinates.length == 0) {
+            throw new IllegalArgumentException("Points array cannot be empty");
+        }
         this.k = pointsCoordinates[0].length;
         Point[] points = Arrays.stream(pointsCoordinates).map(Point::new).toArray(Point[] ::new);
-        for (Point point : points)
-            if (point.getDimension() != k) throw new IllegalArgumentException("Points must have the same dimension");
+        for (Point point : points) {
+            if (point.getDimension() != k) {
+                throw new IllegalArgumentException("Points must have the same dimension");
+            }
+        }
         this.root = build(points, 0);
     }
 
@@ -119,7 +129,9 @@ public static int comparableDistance(Point p1, Point p2) {
         public static int comparableDistanceExceptAxis(Point p1, Point p2, int axis) {
             int distance = 0;
             for (int i = 0; i < p1.getDimension(); i++) {
-                if (i == axis) continue;
+                if (i == axis) {
+                    continue;
+                }
                 int t = p1.getCoordinate(i) - p2.getCoordinate(i);
                 distance += t * t;
             }
@@ -164,10 +176,11 @@ public int getAxis() {
          * @return The nearest child Node
          */
         public Node getNearChild(Point point) {
-            if (point.getCoordinate(axis) < this.point.getCoordinate(axis))
+            if (point.getCoordinate(axis) < this.point.getCoordinate(axis)) {
                 return left;
-            else
+            } else {
                 return right;
+            }
         }
 
         /**
@@ -178,10 +191,11 @@ public Node getNearChild(Point point) {
          * @return The farthest child Node
          */
         public Node getFarChild(Point point) {
-            if (point.getCoordinate(axis) < this.point.getCoordinate(axis))
+            if (point.getCoordinate(axis) < this.point.getCoordinate(axis)) {
                 return right;
-            else
+            } else {
                 return left;
+            }
         }
 
         /**
@@ -207,9 +221,13 @@ public Node getRoot() {
      * @return The root of the KDTree
      */
     private Node build(Point[] points, int depth) {
-        if (points.length == 0) return null;
+        if (points.length == 0) {
+            return null;
+        }
         int axis = depth % k;
-        if (points.length == 1) return new Node(points[0], axis);
+        if (points.length == 1) {
+            return new Node(points[0], axis);
+        }
         Arrays.sort(points, Comparator.comparingInt(o -> o.getCoordinate(axis)));
         int median = points.length >> 1;
         Node node = new Node(points[median], axis);
@@ -225,7 +243,9 @@ private Node build(Point[] points, int depth) {
      *
      */
     public void insert(Point point) {
-        if (point.getDimension() != k) throw new IllegalArgumentException("Point has wrong dimension");
+        if (point.getDimension() != k) {
+            throw new IllegalArgumentException("Point has wrong dimension");
+        }
         root = insert(root, point, 0);
     }
 
@@ -240,11 +260,14 @@ public void insert(Point point) {
      */
     private Node insert(Node root, Point point, int depth) {
         int axis = depth % k;
-        if (root == null) return new Node(point, axis);
-        if (point.getCoordinate(axis) < root.getAxisCoordinate())
+        if (root == null) {
+            return new Node(point, axis);
+        }
+        if (point.getCoordinate(axis) < root.getAxisCoordinate()) {
             root.left = insert(root.left, point, depth + 1);
-        else
+        } else {
             root.right = insert(root.right, point, depth + 1);
+        }
 
         return root;
     }
@@ -257,7 +280,9 @@ private Node insert(Node root, Point point, int depth) {
      * @return The Node corresponding to the specified point
      */
     public Optional<Node> search(Point point) {
-        if (point.getDimension() != k) throw new IllegalArgumentException("Point has wrong dimension");
+        if (point.getDimension() != k) {
+            throw new IllegalArgumentException("Point has wrong dimension");
+        }
         return search(root, point);
     }
 
@@ -270,8 +295,12 @@ public Optional<Node> search(Point point) {
      * @return The Node corresponding to the specified point
      */
     public Optional<Node> search(Node root, Point point) {
-        if (root == null) return Optional.empty();
-        if (root.point.equals(point)) return Optional.of(root);
+        if (root == null) {
+            return Optional.empty();
+        }
+        if (root.point.equals(point)) {
+            return Optional.of(root);
+        }
         return search(root.getNearChild(point), point);
     }
 
@@ -295,9 +324,13 @@ public Point findMin(int axis) {
      * @return The Node with minimum value in the specified axis of the point
      */
     public Node findMin(Node root, int axis) {
-        if (root == null) return null;
+        if (root == null) {
+            return null;
+        }
         if (root.getAxis() == axis) {
-            if (root.left == null) return root;
+            if (root.left == null) {
+                return root;
+            }
             return findMin(root.left, axis);
         } else {
             Node left = findMin(root.left, axis);
@@ -327,9 +360,13 @@ public Point findMax(int axis) {
      * @return The Node with maximum value in the specified axis of the point
      */
     public Node findMax(Node root, int axis) {
-        if (root == null) return null;
+        if (root == null) {
+            return null;
+        }
         if (root.getAxis() == axis) {
-            if (root.right == null) return root;
+            if (root.right == null) {
+                return root;
+            }
             return findMax(root.right, axis);
         } else {
             Node left = findMax(root.left, axis);
@@ -358,7 +395,9 @@ public void delete(Point point) {
      * @return The new root of the subtree
      */
     private Node delete(Node root, Node node) {
-        if (root == null) return null;
+        if (root == null) {
+            return null;
+        }
         if (root.equals(node)) {
             if (root.right != null) {
                 Node min = findMin(root.right, root.getAxis());
@@ -368,13 +407,15 @@ private Node delete(Node root, Node node) {
                 Node min = findMin(root.left, root.getAxis());
                 root.point = min.point;
                 root.left = delete(root.left, min);
-            } else
+            } else {
                 return null;
+            }
         }
-        if (root.getAxisCoordinate() < node.point.getCoordinate(root.getAxis()))
+        if (root.getAxisCoordinate() < node.point.getCoordinate(root.getAxis())) {
             root.left = delete(root.left, node);
-        else
+        } else {
             root.right = delete(root.right, node);
+        }
         return root;
     }
 
@@ -395,13 +436,21 @@ public Point findNearest(Point point) {
      * @param nearest The nearest neighbor found so far.
      * */
     private Node findNearest(Node root, Point point, Node nearest) {
-        if (root == null) return nearest;
-        if (root.point.equals(point)) return root;
+        if (root == null) {
+            return nearest;
+        }
+        if (root.point.equals(point)) {
+            return root;
+        }
         int distance = Point.comparableDistance(root.point, point);
         int distanceExceptAxis = Point.comparableDistanceExceptAxis(root.point, point, root.getAxis());
-        if (distance < Point.comparableDistance(nearest.point, point)) nearest = root;
+        if (distance < Point.comparableDistance(nearest.point, point)) {
+            nearest = root;
+        }
         nearest = findNearest(root.getNearChild(point), point, nearest);
-        if (distanceExceptAxis < Point.comparableDistance(nearest.point, point)) nearest = findNearest(root.getFarChild(point), point, nearest);
+        if (distanceExceptAxis < Point.comparableDistance(nearest.point, point)) {
+            nearest = findNearest(root.getFarChild(point), point, nearest);
+        }
         return nearest;
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java b/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java
index 1d8febff4b5f..e7a8e23d6610 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java
@@ -40,11 +40,19 @@ public void applyUpdate(int diff) {
          * Shift the lazy value of this node to its children.
          */
         public void shift() {
-            if (lazy == 0) return;
-            if (this.left == null && this.right == null) return;
+            if (lazy == 0) {
+                return;
+            }
+            if (this.left == null && this.right == null) {
+                return;
+            }
             this.value += this.lazy;
-            if (this.left != null) this.left.applyUpdate(this.lazy);
-            if (this.right != null) this.right.applyUpdate(this.lazy);
+            if (this.left != null) {
+                this.left.applyUpdate(this.lazy);
+            }
+            if (this.right != null) {
+                this.right.applyUpdate(this.lazy);
+            }
             this.lazy = 0;
         }
 
@@ -56,8 +64,12 @@ public void shift() {
          * @return The new Node.
          */
         static Node merge(Node left, Node right) {
-            if (left == null) return right;
-            if (right == null) return left;
+            if (left == null) {
+                return right;
+            }
+            if (right == null) {
+                return left;
+            }
             Node result = new Node(left.start, right.end, left.value + right.value);
             result.left = left;
             result.right = right;
@@ -97,7 +109,9 @@ public LazySegmentTree(int[] array) {
      * @return The root of the new LazySegmentTree.
      */
     private Node buildTree(int[] array, int start, int end) {
-        if (end - start < 2) return new Node(start, end, array[start]);
+        if (end - start < 2) {
+            return new Node(start, end, array[start]);
+        }
         int mid = (start + end) >> 1;
         Node left = buildTree(array, start, mid);
         Node right = buildTree(array, mid, end);
@@ -117,7 +131,9 @@ private void updateRange(int left, int right, int diff, Node curr) {
             curr.applyUpdate(diff);
             return;
         }
-        if (left >= curr.end || right <= curr.start) return;
+        if (left >= curr.end || right <= curr.start) {
+            return;
+        }
         curr.shift();
         updateRange(left, right, diff, curr.left);
         updateRange(left, right, diff, curr.right);
@@ -133,8 +149,12 @@ private void updateRange(int left, int right, int diff, Node curr) {
      * @return The Node representing the sum of the given range.
      */
     private Node getRange(int left, int right, Node curr) {
-        if (left <= curr.start && curr.end <= right) return curr;
-        if (left >= curr.end || right <= curr.start) return null;
+        if (left <= curr.start && curr.end <= right) {
+            return curr;
+        }
+        if (left >= curr.end || right <= curr.start) {
+            return null;
+        }
         curr.shift();
         return Node.merge(getRange(left, right, curr.left), getRange(left, right, curr.right));
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java
index 6a0eef369407..3aceac4d1852 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java
@@ -36,15 +36,21 @@ public static List<Integer> recursivePreOrder(BinaryTree.Node root) {
 
     public static List<Integer> iterativePreOrder(BinaryTree.Node root) {
         List<Integer> result = new ArrayList<>();
-        if (root == null) return result;
+        if (root == null) {
+            return result;
+        }
 
         Deque<BinaryTree.Node> stack = new LinkedList<>();
         stack.push(root);
         while (!stack.isEmpty()) {
             BinaryTree.Node node = stack.pop();
             result.add(node.data);
-            if (node.right != null) stack.push(node.right);
-            if (node.left != null) stack.push(node.left);
+            if (node.right != null) {
+                stack.push(node.right);
+            }
+            if (node.left != null) {
+                stack.push(node.left);
+            }
         }
 
         return result;
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java b/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java
index 883eadd1840a..cff27c12f1ca 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java
@@ -52,16 +52,22 @@ public static boolean check(BinaryTree.Node p, BinaryTree.Node q) {
             BinaryTree.Node second = q2.poll();
             // check that some node can be null
             // if the check is true: both nodes are null or both nodes are not null
-            if (!equalNodes(first, second)) return false;
+            if (!equalNodes(first, second)) {
+                return false;
+            }
 
             if (first != null) {
-                if (!equalNodes(first.left, second.left)) return false;
+                if (!equalNodes(first.left, second.left)) {
+                    return false;
+                }
                 if (first.left != null) {
                     q1.add(first.left);
                     q2.add(second.left);
                 }
 
-                if (!equalNodes(first.right, second.right)) return false;
+                if (!equalNodes(first.right, second.right)) {
+                    return false;
+                }
                 if (first.right != null) {
                     q1.add(first.right);
                     q2.add(second.right);
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
index de75126044ae..9962cca217a0 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
@@ -18,7 +18,9 @@ public static boolean maxSum(int[] a, int predictedAnswer) {
             // running sum of all the indexs are stored
             sum = Math.max(sum, runningSum);
             // the max is stored inorder to the get the maximum sum
-            if (runningSum < 0) runningSum = 0;
+            if (runningSum < 0) {
+                runningSum = 0;
+            }
             // if running sum is negative then it is initialized to zero
         }
         // for-each loop is used to iterate over the array and find the maximum subarray sum
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java b/src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java
index 0840e08c531c..e31bb73096e8 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java
@@ -69,19 +69,19 @@ private void calculateCost() {
      */
     private int runningCost(int process, int machine) {
 
-        if (process == 0) // refers to the first process,which does not require for a previous one
-                          // to have been executed
+        if (process == 0) { // refers to the first process,which does not require for a previous one
+            // to have been executed
             return run[process][machine];
-        else {
+        } else {
 
             int[] runningCosts = new int[numberMachines]; // stores the costs of executing our Process depending on
-                                                          // the Machine the previous one was executed
+            // the Machine the previous one was executed
 
-            for (int k = 0; k < numberMachines; k++) // computes the cost of executing the previous
-                                                     // process to each and every Machine
+            for (int k = 0; k < numberMachines; k++) { // computes the cost of executing the previous
+                // process to each and every Machine
                 runningCosts[k] = cost[process - 1][k] + transfer[k][machine] + run[process][machine]; // transferring the result to our Machine and executing
-                                                                                                       // the Process to our Machine
-
+                // the Process to our Machine
+            }
             return findMin(runningCosts); // returns the minimum running cost
         }
     }
@@ -98,7 +98,9 @@ private int findMin(int[] costArr) {
 
         for (int i = 1; i < costArr.length; i++) {
 
-            if (costArr[i] < costArr[min]) min = i;
+            if (costArr[i] < costArr[min]) {
+                min = i;
+            }
         }
         return costArr[min];
     }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java
index af31294f7e0e..cbe3ccae4ac7 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java
@@ -29,12 +29,16 @@ public static int getCount(int[] arr, int target) {
         for (int i = 0; i < n; i++) {
             dp[i][0] = 1;
         }
-        if (arr[0] <= target) dp[0][arr[0]] = 1;
+        if (arr[0] <= target) {
+            dp[0][arr[0]] = 1;
+        }
         for (int t = 1; t <= target; t++) {
             for (int idx = 1; idx < n; idx++) {
                 int notpick = dp[idx - 1][t];
                 int pick = 0;
-                if (arr[idx] <= t) pick += dp[idx - 1][target - t];
+                if (arr[idx] <= t) {
+                    pick += dp[idx - 1][target - t];
+                }
                 dp[idx][target] = pick + notpick;
             }
         }
@@ -52,14 +56,18 @@ public static int getCountSO(int[] arr, int target) {
         int n = arr.length;
         int[] prev = new int[target + 1];
         prev[0] = 1;
-        if (arr[0] <= target) prev[arr[0]] = 1;
+        if (arr[0] <= target) {
+            prev[arr[0]] = 1;
+        }
         for (int ind = 1; ind < n; ind++) {
             int[] cur = new int[target + 1];
             cur[0] = 1;
             for (int t = 1; t <= target; t++) {
                 int notTaken = prev[t];
                 int taken = 0;
-                if (arr[ind] <= t) taken = prev[t - arr[ind]];
+                if (arr[ind] <= t) {
+                    taken = prev[t - arr[ind]];
+                }
                 cur[t] = notTaken + taken;
             }
             prev = cur;
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java b/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
index 407566f481a0..3ff6cc620236 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java
@@ -15,8 +15,12 @@ private Tribonacci() {
      * @return the n-th Tribonacci number
      */
     public static int compute(int n) {
-        if (n == 0) return 0;
-        if (n == 1 || n == 2) return 1;
+        if (n == 0) {
+            return 0;
+        }
+        if (n == 1 || n == 2) {
+            return 1;
+        }
 
         int first = 0;
         int second = 1;
diff --git a/src/main/java/com/thealgorithms/geometry/GrahamScan.java b/src/main/java/com/thealgorithms/geometry/GrahamScan.java
index 4f4aebaed971..2773d03b4769 100644
--- a/src/main/java/com/thealgorithms/geometry/GrahamScan.java
+++ b/src/main/java/com/thealgorithms/geometry/GrahamScan.java
@@ -32,13 +32,21 @@ public GrahamScan(Point[] points) {
         // find index of first point not equal to a[0] (indexPoint1) and the first point that's not
         // collinear with either (indexPoint2).
         int indexPoint1;
-        for (indexPoint1 = 1; indexPoint1 < points.length; indexPoint1++)
-            if (!points[0].equals(points[indexPoint1])) break;
-        if (indexPoint1 == points.length) return;
+        for (indexPoint1 = 1; indexPoint1 < points.length; indexPoint1++) {
+            if (!points[0].equals(points[indexPoint1])) {
+                break;
+            }
+        }
+        if (indexPoint1 == points.length) {
+            return;
+        }
 
         int indexPoint2;
-        for (indexPoint2 = indexPoint1 + 1; indexPoint2 < points.length; indexPoint2++)
-            if (Point.orientation(points[0], points[indexPoint1], points[indexPoint2]) != 0) break;
+        for (indexPoint2 = indexPoint1 + 1; indexPoint2 < points.length; indexPoint2++) {
+            if (Point.orientation(points[0], points[indexPoint1], points[indexPoint2]) != 0) {
+                break;
+            }
+        }
         hull.push(points[indexPoint2 - 1]);
 
         // Now we simply add the point to the stack based on the orientation.
@@ -57,7 +65,9 @@ public GrahamScan(Point[] points) {
      */
     public Iterable<Point> hull() {
         Stack<Point> s = new Stack<>();
-        for (Point p : hull) s.push(p);
+        for (Point p : hull) {
+            s.push(p);
+        }
         return s;
     }
 
@@ -112,7 +122,9 @@ public static int orientation(Point a, Point b, Point c) {
          */
         public int compareTo(Point p2) {
             int res = Integer.compare(this.y, p2.y);
-            if (res == 0) res = Integer.compare(this.x, p2.x);
+            if (res == 0) {
+                res = Integer.compare(this.x, p2.x);
+            }
             return res;
         }
 
@@ -133,19 +145,21 @@ public int compare(Point p1, Point p2) {
                 int dx2 = p2.x - x;
                 int dy2 = p2.y - y;
 
-                if (dy1 >= 0 && dy2 < 0)
+                if (dy1 >= 0 && dy2 < 0) {
                     return -1; // q1 above; q2 below
-                else if (dy2 >= 0 && dy1 < 0)
+                } else if (dy2 >= 0 && dy1 < 0) {
                     return +1; // q1 below; q2 above
-                else if (dy1 == 0 && dy2 == 0) { // 3-collinear and horizontal
-                    if (dx1 >= 0 && dx2 < 0)
+                } else if (dy1 == 0 && dy2 == 0) { // 3-collinear and horizontal
+                    if (dx1 >= 0 && dx2 < 0) {
                         return -1;
-                    else if (dx2 >= 0 && dx1 < 0)
+                    } else if (dx2 >= 0 && dx1 < 0) {
                         return +1;
-                    else
+                    } else {
                         return 0;
-                } else
+                    }
+                } else {
                     return -orientation(Point.this, p1, p2); // both above or below
+                }
             }
         }
 
diff --git a/src/main/java/com/thealgorithms/io/BufferedReader.java b/src/main/java/com/thealgorithms/io/BufferedReader.java
index fa0237a48049..66673fe281ae 100644
--- a/src/main/java/com/thealgorithms/io/BufferedReader.java
+++ b/src/main/java/com/thealgorithms/io/BufferedReader.java
@@ -44,7 +44,9 @@ public BufferedReader(InputStream input) throws IOException {
 
     public BufferedReader(InputStream input, int bufferSize) throws IOException {
         this.input = input;
-        if (input.available() == -1) throw new IOException("Empty or already closed stream provided");
+        if (input.available() == -1) {
+            throw new IOException("Empty or already closed stream provided");
+        }
 
         this.bufferSize = bufferSize;
         buffer = new byte[bufferSize];
@@ -55,7 +57,9 @@ public BufferedReader(InputStream input, int bufferSize) throws IOException {
      */
     public int read() throws IOException {
         if (needsRefill()) {
-            if (foundEof) return -1;
+            if (foundEof) {
+                return -1;
+            }
             // the buffer is empty, or the buffer has
             // been completely read and needs to be refilled
             refill();
@@ -69,10 +73,11 @@ public int read() throws IOException {
 
     public int available() throws IOException {
         int available = input.available();
-        if (needsRefill())
+        if (needsRefill()) {
             // since the block is already empty,
             // we have no responsibility yet
             return available;
+        }
         return bufferPos - posRead + available;
     }
 
@@ -90,10 +95,14 @@ public int peek() throws IOException {
 
     public int peek(int n) throws IOException {
         int available = available();
-        if (n >= available) throw new IOException("Out of range, available %d, but trying with %d".formatted(available, n));
+        if (n >= available) {
+            throw new IOException("Out of range, available %d, but trying with %d".formatted(available, n));
+        }
         pushRefreshData();
 
-        if (n >= bufferSize) throw new IllegalAccessError("Cannot peek %s, maximum upto %s (Buffer Limit)".formatted(n, bufferSize));
+        if (n >= bufferSize) {
+            throw new IllegalAccessError("Cannot peek %s, maximum upto %s (Buffer Limit)".formatted(n, bufferSize));
+        }
         return buffer[n];
     }
 
@@ -105,7 +114,9 @@ public int peek(int n) throws IOException {
      */
 
     private void pushRefreshData() throws IOException {
-        for (int i = posRead, j = 0; i < bufferSize; i++, j++) buffer[j] = buffer[i];
+        for (int i = posRead, j = 0; i < bufferSize; i++, j++) {
+            buffer[j] = buffer[i];
+        }
 
         bufferPos -= posRead;
         posRead = 0;
@@ -127,11 +138,12 @@ public byte[] readBlock() throws IOException {
 
         byte[] cloned = new byte[bufferSize];
         // arraycopy() function is better than clone()
-        if (bufferPos >= 0)
+        if (bufferPos >= 0) {
             System.arraycopy(buffer, 0, cloned, 0,
                 // important to note that, bufferSize does not stay constant
                 // once the class is defined. See justRefill() function
                 bufferSize);
+        }
         // we assume that already a chunk
         // has been read
         refill();
@@ -168,7 +180,9 @@ private void justRefill() throws IOException {
     }
 
     private void assertStreamOpen() {
-        if (input == null) throw new IllegalStateException("Input Stream already closed!");
+        if (input == null) {
+            throw new IllegalStateException("Input Stream already closed!");
+        }
     }
 
     public void close() throws IOException {
diff --git a/src/main/java/com/thealgorithms/maths/AliquotSum.java b/src/main/java/com/thealgorithms/maths/AliquotSum.java
index 5a5555777425..0dbc58bed605 100644
--- a/src/main/java/com/thealgorithms/maths/AliquotSum.java
+++ b/src/main/java/com/thealgorithms/maths/AliquotSum.java
@@ -34,7 +34,9 @@ public static int getAliquotValue(int number) {
      * @return aliquot sum of given {@code number}
      */
     public static int getAliquotSum(int n) {
-        if (n <= 0) return -1;
+        if (n <= 0) {
+            return -1;
+        }
         int sum = 1;
         double root = Math.sqrt(n);
         /*
@@ -53,7 +55,9 @@ public static int getAliquotSum(int n) {
         }
         // if n is a perfect square then its root was added twice in above loop, so subtracting root
         // from sum
-        if (root == (int) root) sum -= root;
+        if (root == (int) root) {
+            sum -= root;
+        }
         return sum;
     }
 }
diff --git a/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java b/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
index 560ce3aabd1a..03c8a8989bb2 100644
--- a/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
+++ b/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
@@ -22,7 +22,9 @@ private AutomorphicNumber() {
      *         {@code false}
      */
     public static boolean isAutomorphic(long n) {
-        if (n < 0) return false;
+        if (n < 0) {
+            return false;
+        }
         long square = n * n; // Calculating square of the number
         long t = n;
         long numberOfdigits = 0;
@@ -42,7 +44,9 @@ public static boolean isAutomorphic(long n) {
      *         {@code false}
      */
     public static boolean isAutomorphic2(long n) {
-        if (n < 0) return false;
+        if (n < 0) {
+            return false;
+        }
         long square = n * n; // Calculating square of the number
         return String.valueOf(square).endsWith(String.valueOf(n));
     }
@@ -56,7 +60,9 @@ public static boolean isAutomorphic2(long n) {
      */
     public static boolean isAutomorphic3(String s) {
         BigInteger n = new BigInteger(s);
-        if (n.signum() == -1) return false; // if number is negative, return false
+        if (n.signum() == -1) {
+            return false; // if number is negative, return false
+        }
         BigInteger square = n.multiply(n); // Calculating square of the number
         return String.valueOf(square).endsWith(String.valueOf(n));
     }
diff --git a/src/main/java/com/thealgorithms/maths/HarshadNumber.java b/src/main/java/com/thealgorithms/maths/HarshadNumber.java
index 0b1ba1285c4d..5792e925a8aa 100644
--- a/src/main/java/com/thealgorithms/maths/HarshadNumber.java
+++ b/src/main/java/com/thealgorithms/maths/HarshadNumber.java
@@ -14,7 +14,9 @@ private HarshadNumber() {
      *         {@code false}
      */
     public static boolean isHarshad(long n) {
-        if (n <= 0) return false;
+        if (n <= 0) {
+            return false;
+        }
 
         long t = n;
         long sumOfDigits = 0;
@@ -35,7 +37,9 @@ public static boolean isHarshad(long n) {
      */
     public static boolean isHarshad(String s) {
         final Long n = Long.valueOf(s);
-        if (n <= 0) return false;
+        if (n <= 0) {
+            return false;
+        }
 
         int sumOfDigits = 0;
         for (char ch : s.toCharArray()) {
diff --git a/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java b/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
index f025f86682a2..eb9750f9ce08 100644
--- a/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
+++ b/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
@@ -16,11 +16,15 @@ private KaprekarNumbers() {
     // Provides a list of kaprekarNumber in a range
     public static List<Long> kaprekarNumberInRange(long start, long end) throws Exception {
         long n = end - start;
-        if (n < 0) throw new Exception("Invalid range");
+        if (n < 0) {
+            throw new Exception("Invalid range");
+        }
         ArrayList<Long> list = new ArrayList<>();
 
         for (long i = start; i <= end; i++) {
-            if (isKaprekarNumber(i)) list.add(i);
+            if (isKaprekarNumber(i)) {
+                list.add(i);
+            }
         }
 
         return list;
diff --git a/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java b/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java
index e25836f713a9..f889213abfcb 100644
--- a/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java
+++ b/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java
@@ -20,7 +20,9 @@ private MillerRabinPrimalityCheck() {
      */
 
     public static boolean millerRabin(long n, int k) { // returns true if n is probably prime, else returns false.
-        if (n < 4) return n == 2 || n == 3;
+        if (n < 4) {
+            return n == 2 || n == 3;
+        }
 
         int s = 0;
         long d = n - 1;
@@ -31,13 +33,17 @@ public static boolean millerRabin(long n, int k) { // returns true if n is proba
         Random rnd = new Random();
         for (int i = 0; i < k; i++) {
             long a = 2 + rnd.nextLong(n) % (n - 3);
-            if (checkComposite(n, a, d, s)) return false;
+            if (checkComposite(n, a, d, s)) {
+                return false;
+            }
         }
         return true;
     }
 
     public static boolean deterministicMillerRabin(long n) { // returns true if n is prime, else returns false.
-        if (n < 2) return false;
+        if (n < 2) {
+            return false;
+        }
 
         int r = 0;
         long d = n - 1;
@@ -47,8 +53,12 @@ public static boolean deterministicMillerRabin(long n) { // returns true if n is
         }
 
         for (int a : new int[] {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37}) {
-            if (n == a) return true;
-            if (checkComposite(n, a, d, r)) return false;
+            if (n == a) {
+                return true;
+            }
+            if (checkComposite(n, a, d, r)) {
+                return false;
+            }
         }
         return true;
     }
@@ -66,10 +76,14 @@ public static boolean deterministicMillerRabin(long n) { // returns true if n is
      */
     private static boolean checkComposite(long n, long a, long d, int s) {
         long x = powerModP(a, d, n);
-        if (x == 1 || x == n - 1) return false;
+        if (x == 1 || x == n - 1) {
+            return false;
+        }
         for (int r = 1; r < s; r++) {
             x = powerModP(x, 2, n);
-            if (x == n - 1) return false;
+            if (x == n - 1) {
+                return false;
+            }
         }
         return true;
     }
@@ -79,11 +93,14 @@ private static long powerModP(long x, long y, long p) {
 
         x = x % p; // Update x if it is more than or equal to p
 
-        if (x == 0) return 0; // In case x is divisible by p;
-
+        if (x == 0) {
+            return 0; // In case x is divisible by p;
+        }
         while (y > 0) {
             // If y is odd, multiply x with result
-            if ((y & 1) == 1) res = multiplyModP(res, x, p);
+            if ((y & 1) == 1) {
+                res = multiplyModP(res, x, p);
+            }
 
             // y must be even now
             y = y >> 1; // y = y/2
diff --git a/src/main/java/com/thealgorithms/maths/PascalTriangle.java b/src/main/java/com/thealgorithms/maths/PascalTriangle.java
index ef6aa41d6e53..95f92fbe1b49 100644
--- a/src/main/java/com/thealgorithms/maths/PascalTriangle.java
+++ b/src/main/java/com/thealgorithms/maths/PascalTriangle.java
@@ -52,10 +52,11 @@ public static int[][] pascal(int n) {
              */
             for (int i = 0; i <= line; i++) {
                 // First and last values in every row are 1
-                if (line == i || i == 0) arr[line][i] = 1;
-                // The rest elements are sum of values just above and left of above
-                else
+                if (line == i || i == 0) {
+                    arr[line][i] = 1;
+                } else {
                     arr[line][i] = arr[line - 1][i - 1] + arr[line - 1][i];
+                }
             }
         }
 
diff --git a/src/main/java/com/thealgorithms/maths/PerfectNumber.java b/src/main/java/com/thealgorithms/maths/PerfectNumber.java
index 49afd23f91bf..2a935b067094 100644
--- a/src/main/java/com/thealgorithms/maths/PerfectNumber.java
+++ b/src/main/java/com/thealgorithms/maths/PerfectNumber.java
@@ -19,7 +19,9 @@ private PerfectNumber() {
      * @return {@code true} if {@code number} is perfect number, otherwise false
      */
     public static boolean isPerfectNumber(int number) {
-        if (number <= 0) return false;
+        if (number <= 0) {
+            return false;
+        }
         int sum = 0;
         /* sum of its positive divisors */
         for (int i = 1; i < number; ++i) {
@@ -37,7 +39,9 @@ public static boolean isPerfectNumber(int number) {
      * @return {@code true} if {@code number} is perfect number, otherwise false
      */
     public static boolean isPerfectNumber2(int n) {
-        if (n <= 0) return false;
+        if (n <= 0) {
+            return false;
+        }
         int sum = 1;
         double root = Math.sqrt(n);
 
@@ -58,7 +62,9 @@ public static boolean isPerfectNumber2(int n) {
 
         // if n is a perfect square then its root was added twice in above loop, so subtracting root
         // from sum
-        if (root == (int) root) sum -= root;
+        if (root == (int) root) {
+            sum -= root;
+        }
 
         return sum == n;
     }
diff --git a/src/main/java/com/thealgorithms/maths/SumWithoutArithmeticOperators.java b/src/main/java/com/thealgorithms/maths/SumWithoutArithmeticOperators.java
index 8bc1afbe8771..5369182a0a94 100644
--- a/src/main/java/com/thealgorithms/maths/SumWithoutArithmeticOperators.java
+++ b/src/main/java/com/thealgorithms/maths/SumWithoutArithmeticOperators.java
@@ -12,7 +12,9 @@ public class SumWithoutArithmeticOperators {
      */
 
     public int getSum(int a, int b) {
-        if (b == 0) return a;
+        if (b == 0) {
+            return a;
+        }
         int sum = a ^ b;
         int carry = (a & b) << 1;
         return getSum(sum, carry);
diff --git a/src/main/java/com/thealgorithms/others/CRC16.java b/src/main/java/com/thealgorithms/others/CRC16.java
index 85e5cd2c13ae..847ce8edab0a 100644
--- a/src/main/java/com/thealgorithms/others/CRC16.java
+++ b/src/main/java/com/thealgorithms/others/CRC16.java
@@ -21,7 +21,9 @@ public static String crc16(String message) {
                 boolean bit = ((b >> (7 - i) & 1) == 1);
                 boolean c15 = ((crc >> 15 & 1) == 1);
                 crc <<= 1;
-                if (c15 ^ bit) crc ^= polynomial;
+                if (c15 ^ bit) {
+                    crc ^= polynomial;
+                }
             }
         }
         crc &= 0xffff;
diff --git a/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java b/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
index 0bafc435aa75..5aa25812dcc2 100644
--- a/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
+++ b/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
@@ -24,7 +24,9 @@ private MaximumSumOfDistinctSubarraysWithLengthK() {
      * @return the maximum sum of distinct subarray of size K.
      */
     public static long maximumSubarraySum(int k, int... nums) {
-        if (nums.length < k) return 0;
+        if (nums.length < k) {
+            return 0;
+        }
         long max = 0; // this will store the max sum which will be our result
         long s = 0; // this will store the sum of every k elements which can be used to compare with
                     // max
diff --git a/src/main/java/com/thealgorithms/scheduling/RRScheduling.java b/src/main/java/com/thealgorithms/scheduling/RRScheduling.java
index 991c9a4f6148..110c97416a42 100644
--- a/src/main/java/com/thealgorithms/scheduling/RRScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/RRScheduling.java
@@ -79,7 +79,9 @@ private void evaluateTurnAroundTime() {
 
             // If the current process has burst time remaining, push the process into the queue
             // again.
-            if (remainingBurstTime[index] > 0) queue.add(index);
+            if (remainingBurstTime[index] > 0) {
+                queue.add(index);
+            }
 
             // If the queue is empty, pick the first process from the list that is not completed.
             if (queue.isEmpty()) {
diff --git a/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java b/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
index 40b3cd0c20e3..53f5d7c8434e 100644
--- a/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
+++ b/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
@@ -29,47 +29,57 @@ static int[] binarySearch(int[][] arr, int target) {
 
             if (arr[midRow][midCol] == target) {
                 return new int[] {midRow, midCol};
-            } else if (arr[midRow][midCol] < target)
+            } else if (arr[midRow][midCol] < target) {
                 startRow = midRow;
-            else
+            } else {
                 endRow = midRow;
+            }
         }
         /*
             if the above search fails to find the target element, these conditions will be used to
            find the target element, which further uses the binary search algorithm in the places
            which were left unexplored.
              */
-        if (arr[startRow][midCol] == target)
+        if (arr[startRow][midCol] == target) {
             return new int[] {
                 startRow,
                 midCol,
             };
+        }
 
-        if (arr[endRow][midCol] == target) return new int[] {endRow, midCol};
+        if (arr[endRow][midCol] == target) {
+            return new int[] {endRow, midCol};
+        }
 
-        if (target <= arr[startRow][midCol - 1]) return binarySearch(arr, target, startRow, 0, midCol - 1);
+        if (target <= arr[startRow][midCol - 1]) {
+            return binarySearch(arr, target, startRow, 0, midCol - 1);
+        }
 
-        if (target >= arr[startRow][midCol + 1] && target <= arr[startRow][colCount - 1]) return binarySearch(arr, target, startRow, midCol + 1, colCount - 1);
+        if (target >= arr[startRow][midCol + 1] && target <= arr[startRow][colCount - 1]) {
+            return binarySearch(arr, target, startRow, midCol + 1, colCount - 1);
+        }
 
-        if (target <= arr[endRow][midCol - 1])
+        if (target <= arr[endRow][midCol - 1]) {
             return binarySearch(arr, target, endRow, 0, midCol - 1);
-        else
+        } else {
             return binarySearch(arr, target, endRow, midCol + 1, colCount - 1);
+        }
     }
 
     static int[] binarySearch(int[][] arr, int target, int row, int colStart, int colEnd) {
         while (colStart <= colEnd) {
             int midIndex = colStart + (colEnd - colStart) / 2;
 
-            if (arr[row][midIndex] == target)
+            if (arr[row][midIndex] == target) {
                 return new int[] {
                     row,
                     midIndex,
                 };
-            else if (arr[row][midIndex] < target)
+            } else if (arr[row][midIndex] < target) {
                 colStart = midIndex + 1;
-            else
+            } else {
                 colEnd = midIndex - 1;
+            }
         }
 
         return new int[] {-1, -1};
diff --git a/src/main/java/com/thealgorithms/searches/KMPSearch.java b/src/main/java/com/thealgorithms/searches/KMPSearch.java
index 3648a4b08b86..8bf2754ff8f7 100644
--- a/src/main/java/com/thealgorithms/searches/KMPSearch.java
+++ b/src/main/java/com/thealgorithms/searches/KMPSearch.java
@@ -32,10 +32,11 @@ int kmpSearch(String pat, String txt) {
             else if (i < n && pat.charAt(j) != txt.charAt(i)) {
                 // Do not match lps[0..lps[j-1]] characters,
                 // they will match anyway
-                if (j != 0)
+                if (j != 0) {
                     j = lps[j - 1];
-                else
+                } else {
                     i = i + 1;
+                }
             }
         }
         System.out.println("No pattern found");
diff --git a/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java b/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
index cdd256150871..d85cb37c4427 100644
--- a/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java
@@ -24,22 +24,23 @@ static int binSearchAlgo(int[] arr, int start, int end, int target) {
             int middle = start + (end - start) / 2;
 
             // Check if the desired element is present at the middle position
-            if (arr[middle] == target) return middle; // returns the index of the middle element
-
-            // Ascending order
+            if (arr[middle] == target) {
+                return middle; // returns the index of the middle element
+            }
             if (ascOrd) {
-                if (arr[middle] < target)
+                // Ascending order
+                if (arr[middle] < target) {
                     start = middle + 1;
-                else
+                } else {
                     end = middle - 1;
-            }
-
-            // Descending order
-            else {
-                if (arr[middle] > target)
+                }
+            } else {
+                // Descending order
+                if (arr[middle] > target) {
                     start = middle + 1;
-                else
+                } else {
                     end = middle - 1;
+                }
             }
         }
         // Element is not present
diff --git a/src/main/java/com/thealgorithms/searches/QuickSelect.java b/src/main/java/com/thealgorithms/searches/QuickSelect.java
index 97eab4bb4046..c89abb00e9da 100644
--- a/src/main/java/com/thealgorithms/searches/QuickSelect.java
+++ b/src/main/java/com/thealgorithms/searches/QuickSelect.java
@@ -56,7 +56,9 @@ private static <T extends Comparable<T>> int selectIndex(List<T> list, int n) {
 
     private static <T extends Comparable<T>> int selectIndex(List<T> list, int left, int right, int n) {
         while (true) {
-            if (left == right) return left;
+            if (left == right) {
+                return left;
+            }
             int pivotIndex = pivot(list, left, right);
             pivotIndex = partition(list, left, right, pivotIndex, n);
             if (n == pivotIndex) {
diff --git a/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java b/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java
index cc8387f6c4f3..81e16dbbbf07 100644
--- a/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java
+++ b/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java
@@ -18,7 +18,9 @@ public static int search(String pattern, String text, int primeNumber) {
         int h = 1;
 
         // The value of h would be "pow(d, patternLength-1)%primeNumber"
-        for (int i = 0; i < patternLength - 1; i++) h = (h * ALPHABET_SIZE) % primeNumber;
+        for (int i = 0; i < patternLength - 1; i++) {
+            h = (h * ALPHABET_SIZE) % primeNumber;
+        }
 
         // Calculate the hash value of pattern and first
         // window of text
@@ -37,7 +39,9 @@ public static int search(String pattern, String text, int primeNumber) {
             if (hashForPattern == hashForText) {
                 /* Check for characters one by one */
                 for (j = 0; j < patternLength; j++) {
-                    if (text.charAt(i + j) != pattern.charAt(j)) break;
+                    if (text.charAt(i + j) != pattern.charAt(j)) {
+                        break;
+                    }
                 }
 
                 // if hashForPattern == hashForText and pattern[0...patternLength-1] = text[i, i+1, ...i+patternLength-1]
@@ -53,7 +57,9 @@ public static int search(String pattern, String text, int primeNumber) {
                 hashForText = (ALPHABET_SIZE * (hashForText - text.charAt(i) * h) + text.charAt(i + patternLength)) % primeNumber;
 
                 // handling negative hashForText
-                if (hashForText < 0) hashForText = (hashForText + primeNumber);
+                if (hashForText < 0) {
+                    hashForText = (hashForText + primeNumber);
+                }
             }
         }
         return index; // return -1 if pattern does not found
diff --git a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
index 6c6284e28019..daf0c12c0978 100644
--- a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
@@ -67,10 +67,11 @@ public static void main(String[] args) {
             RecursiveBinarySearch<Integer> searcher = new RecursiveBinarySearch<>();
             int res = searcher.find(a, t);
 
-            if (res == -1)
+            if (res == -1) {
                 System.out.println("Element not found in the array.");
-            else
+            } else {
                 System.out.println("Element found at index " + res);
+            }
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java b/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java
index 60cb5aa7aa69..5a6ba256521f 100644
--- a/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java
@@ -44,7 +44,9 @@ private static <T extends Comparable<T>> void dualPivotQuicksort(T[] array, int
      * @param right The last index of an array Finds the partition index of an array
      */
     private static <T extends Comparable<T>> int[] partition(T[] array, int left, int right) {
-        if (array[left].compareTo(array[right]) > 0) swap(array, left, right);
+        if (array[left].compareTo(array[right]) > 0) {
+            swap(array, left, right);
+        }
 
         T pivot1 = array[left];
         T pivot2 = array[right];
@@ -61,11 +63,15 @@ private static <T extends Comparable<T>> int[] partition(T[] array, int left, in
 
             // If element is greater or equal to pivot2
             else if (array[less].compareTo(pivot2) >= 0) {
-                while (less < great && array[great].compareTo(pivot2) > 0) great--;
+                while (less < great && array[great].compareTo(pivot2) > 0) {
+                    great--;
+                }
 
                 swap(array, less, great--);
 
-                if (array[less].compareTo(pivot1) < 0) swap(array, less, left++);
+                if (array[less].compareTo(pivot1) < 0) {
+                    swap(array, less, left++);
+                }
             }
 
             less++;
diff --git a/src/main/java/com/thealgorithms/sorts/InsertionSort.java b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
index 3b8c286515bc..36aba615ba94 100644
--- a/src/main/java/com/thealgorithms/sorts/InsertionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
@@ -38,12 +38,17 @@ public <T extends Comparable<T>> T[] sort(T[] array, int lo, int hi) {
     public <T extends Comparable<T>> T[] sentinelSort(T[] array) {
         int minElemIndex = 0;
         int n = array.length;
-        if (n < 1) return array;
+        if (n < 1) {
+            return array;
+        }
 
         // put the smallest element to the 0 position as a sentinel, which will allow us to avoid
         // redundant comparisons like `j > 0` further
-        for (int i = 1; i < n; i++)
-            if (SortUtils.less(array[i], array[minElemIndex])) minElemIndex = i;
+        for (int i = 1; i < n; i++) {
+            if (SortUtils.less(array[i], array[minElemIndex])) {
+                minElemIndex = i;
+            }
+        }
         SortUtils.swap(array, 0, minElemIndex);
 
         for (int i = 2; i < n; i++) {
diff --git a/src/main/java/com/thealgorithms/sorts/LinkListSort.java b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
index fdbfe3130e41..c9000f7e3778 100644
--- a/src/main/java/com/thealgorithms/sorts/LinkListSort.java
+++ b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
@@ -30,10 +30,11 @@ public static boolean isSorted(int[] p, int option) {
                 // New nodes are created and values are added
                 fresh = new Node(); // Node class is called
                 fresh.val = a[i]; // Node val is stored
-                if (start == null)
+                if (start == null) {
                     start = fresh;
-                else
+                } else {
                     prev.next = fresh;
+                }
                 prev = fresh;
             }
             start = nm.sortByMergeSort(start);
@@ -58,10 +59,11 @@ public static boolean isSorted(int[] p, int option) {
                 // New nodes are created and values are added
                 fresh1 = new Node(); // New node is created
                 fresh1.val = a[i1]; // Value is stored in the value part of the node
-                if (start1 == null)
+                if (start1 == null) {
                     start1 = fresh1;
-                else
+                } else {
                     prev1.next = fresh1;
+                }
                 prev1 = fresh1;
             }
             Task1 kk = new Task1();
@@ -87,10 +89,11 @@ public static boolean isSorted(int[] p, int option) {
                 // New nodes are created and values are added
                 fresh2 = new Node(); // Node class is created
                 fresh2.val = a[i2]; // Value is stored in the value part of the Node
-                if (start2 == null)
+                if (start2 == null) {
                     start2 = fresh2;
-                else
+                } else {
                     prev2.next = fresh2;
+                }
                 prev2 = fresh2;
             }
             start2 = mm.sortByHeapSort(start2);
@@ -116,7 +119,9 @@ public static boolean isSorted(int[] p, int option) {
 
     boolean compare(int[] a, int[] b) {
         for (int i = 0; i < a.length; i++) {
-            if (a[i] != b[i]) return false;
+            if (a[i] != b[i]) {
+                return false;
+            }
         }
         return true;
         // Both the arrays are checked for equalness. If both are equal then true is
@@ -147,7 +152,9 @@ class Task {
     private int[] a;
 
     public Node sortByMergeSort(Node head) {
-        if (head == null || head.next == null) return head;
+        if (head == null || head.next == null) {
+            return head;
+        }
         int c = count(head);
         a = new int[c];
         // Array of size c is created
@@ -193,10 +200,11 @@ void task1(int[] n, int s, int m, int e) {
         int j = m + 1;
         int[] b = new int[e - s + 1];
         while (i <= m && j <= e) {
-            if (n[j] >= n[i])
+            if (n[j] >= n[i]) {
                 b[k++] = n[i++];
-            else
+            } else {
                 b[k++] = n[j++];
+            }
         }
         // Smallest number is stored after checking from both the arrays
         while (i <= m) {
@@ -215,7 +223,9 @@ void task1(int[] n, int s, int m, int e) {
 class Task1 {
 
     public Node sortByInsertionSort(Node head) {
-        if (head == null || head.next == null) return head;
+        if (head == null || head.next == null) {
+            return head;
+        }
         int c = count(head);
         int[] a = new int[c];
         // Array of size c is created
@@ -257,7 +267,9 @@ class Task2 {
     private int[] a;
 
     public Node sortByHeapSort(Node head) {
-        if (head == null || head.next == null) return head;
+        if (head == null || head.next == null) {
+            return head;
+        }
         int c = count(head);
         a = new int[c];
         // Array of size c is created
@@ -304,8 +316,12 @@ void task1(int[] n, int k, int i) {
         int p = i;
         int l = 2 * i + 1;
         int r = 2 * i + 2;
-        if (l < k && n[l] > n[p]) p = l;
-        if (r < k && n[r] > n[p]) p = r;
+        if (l < k && n[l] > n[p]) {
+            p = l;
+        }
+        if (r < k && n[r] > n[p]) {
+            p = r;
+        }
         if (p != i) {
             int d = n[p];
             n[p] = n[i];
diff --git a/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java b/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
index 9c0ab45b6a3c..42fd026b117b 100644
--- a/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
@@ -12,7 +12,9 @@ public class PigeonholeSort {
     void sort(Integer[] array) {
         int maxElement = array[0];
         for (int element : array) {
-            if (element > maxElement) maxElement = element;
+            if (element > maxElement) {
+                maxElement = element;
+            }
         }
 
         int numOfPigeonholes = 1 + maxElement;
diff --git a/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java b/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java
index b048d0245b64..ed2f538f4d89 100644
--- a/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java
+++ b/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java
@@ -22,7 +22,9 @@ private SortUtilsRandomGenerator() {
      */
     public static Double[] generateArray(int size) {
         Double[] arr = new Double[size];
-        for (int i = 0; i < size; i++) arr[i] = generateDouble();
+        for (int i = 0; i < size; i++) {
+            arr[i] = generateDouble();
+        }
         return arr;
     }
 
diff --git a/src/main/java/com/thealgorithms/sorts/StrandSort.java b/src/main/java/com/thealgorithms/sorts/StrandSort.java
index 7e2251d70640..51600812bbb1 100644
--- a/src/main/java/com/thealgorithms/sorts/StrandSort.java
+++ b/src/main/java/com/thealgorithms/sorts/StrandSort.java
@@ -9,7 +9,9 @@ private StrandSort() {
 
     // note: the input list is destroyed
     public static <E extends Comparable<? super E>> LinkedList<E> strandSort(LinkedList<E> list) {
-        if (list.size() <= 1) return list;
+        if (list.size() <= 1) {
+            return list;
+        }
 
         LinkedList<E> result = new LinkedList<E>();
         while (list.size() > 0) {
@@ -31,10 +33,11 @@ private static <E extends Comparable<? super E>> LinkedList<E> merge(LinkedList<
         LinkedList<E> result = new LinkedList<E>();
         while (!left.isEmpty() && !right.isEmpty()) {
             // change the direction of this comparison to change the direction of the sort
-            if (left.peek().compareTo(right.peek()) <= 0)
+            if (left.peek().compareTo(right.peek()) <= 0) {
                 result.add(left.remove());
-            else
+            } else {
                 result.add(right.remove());
+            }
         }
         result.addAll(left);
         result.addAll(right);
diff --git a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
index dd3a763bb197..e4ed240a9947 100644
--- a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
@@ -69,7 +69,9 @@ static class Graph {
          * */
         public void addEdge(String label, String... next) {
             adj.put(label, new Vertex(label));
-            if (!next[0].isEmpty()) Collections.addAll(adj.get(label).next, next);
+            if (!next[0].isEmpty()) {
+                Collections.addAll(adj.get(label).next, next);
+            }
         }
     }
 
diff --git a/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java b/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java
index 4d37da0e7c31..6eae06ad7efc 100644
--- a/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java
+++ b/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java
@@ -51,7 +51,9 @@ public static int[] findNextSmallerElements(int[] array) {
         Arrays.fill(result, -1);
 
         for (int i = 0; i < array.length; i++) {
-            while (!stack.empty() && stack.peek() >= array[i]) stack.pop();
+            while (!stack.empty() && stack.peek() >= array[i]) {
+                stack.pop();
+            }
             if (stack.empty()) {
                 result[i] = -1;
             } else {
diff --git a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
index c69a511c2c17..118a3df381c9 100644
--- a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
+++ b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
@@ -35,11 +35,17 @@ public static boolean isOperator(char token) {
 
     public static boolean isValidPostfixExpression(String postfix) {
         /* Postfix expression length should NOT be less than 3 */
-        if (postfix.length() < 3) return false;
+        if (postfix.length() < 3) {
+            return false;
+        }
 
         /* First two characters should NOT be operators */
-        if (isOperator(postfix.charAt(0))) return false;
-        if (isOperator(postfix.charAt(1))) return false;
+        if (isOperator(postfix.charAt(0))) {
+            return false;
+        }
+        if (isOperator(postfix.charAt(1))) {
+            return false;
+        }
 
         int operandCount = 0;
         int operatorCount = 0;
@@ -51,14 +57,18 @@ public static boolean isValidPostfixExpression(String postfix) {
 
             if (isOperator(token)) {
                 operatorCount++;
-                if (operatorCount >= operandCount) return false;
+                if (operatorCount >= operandCount) {
+                    return false;
+                }
             } else {
                 if (operatorCount == 0) {
                     operandCount++;
                     continue;
                 }
 
-                if (operandCount != operatorCount + 1) return false;
+                if (operandCount != operatorCount + 1) {
+                    return false;
+                }
 
                 /* Operand count is set to 2 because:-
                  *
@@ -80,7 +90,9 @@ public static boolean isValidPostfixExpression(String postfix) {
     public static String getPostfixToInfix(String postfix) {
         String infix = "";
 
-        if (postfix.isEmpty()) return infix;
+        if (postfix.isEmpty()) {
+            return infix;
+        }
 
         /* Validate Postfix expression before proceeding with the Infix conversion */
         if (!isValidPostfixExpression(postfix)) {
diff --git a/src/main/java/com/thealgorithms/strings/Anagrams.java b/src/main/java/com/thealgorithms/strings/Anagrams.java
index 352d2308c5ea..106be5e1a596 100644
--- a/src/main/java/com/thealgorithms/strings/Anagrams.java
+++ b/src/main/java/com/thealgorithms/strings/Anagrams.java
@@ -96,7 +96,9 @@ boolean approach3(String s, String t) {
                 b[t.charAt(i) - 'a']++;
             }
             for (int i = 0; i < 26; i++) {
-                if (a[i] != b[i]) return false;
+                if (a[i] != b[i]) {
+                    return false;
+                }
             }
             return true;
         }
diff --git a/src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java b/src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java
index 140e668fc841..cc99a16facc3 100644
--- a/src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java
+++ b/src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java
@@ -16,20 +16,21 @@ public static int lengthOfLongestSubstring(String s) {
             char temp = s.charAt(i);
 
             // adding key to map if not present
-            if (!map.containsKey(temp)) map.put(temp, 0);
-            // checking if the first value is the dublicate value
-            else if (s.charAt(start) == temp)
+            if (!map.containsKey(temp)) {
+                map.put(temp, 0);
+            } else if (s.charAt(start) == temp) {
                 start++;
-            // checking if the previous value is dublicate value
-            else if (s.charAt(i - 1) == temp) {
-                if (max < map.size()) max = map.size();
+            } else if (s.charAt(i - 1) == temp) {
+                if (max < map.size()) {
+                    max = map.size();
+                }
                 map = new HashMap<>();
                 start = i;
                 i--;
-            }
-            // last possible place where dublicate value can be is between start and i
-            else {
-                if (max < map.size()) max = map.size();
+            } else {
+                if (max < map.size()) {
+                    max = map.size();
+                }
                 while (s.charAt(start) != temp) {
                     map.remove(s.charAt(start));
                     start++;
@@ -39,7 +40,9 @@ else if (s.charAt(i - 1) == temp) {
 
             i++;
         }
-        if (max < map.size()) max = map.size();
+        if (max < map.size()) {
+            max = map.size();
+        }
         return max;
     }
 }
diff --git a/src/main/java/com/thealgorithms/strings/MyAtoi.java b/src/main/java/com/thealgorithms/strings/MyAtoi.java
index 0aed13f936a7..f58ab1acf8c5 100644
--- a/src/main/java/com/thealgorithms/strings/MyAtoi.java
+++ b/src/main/java/com/thealgorithms/strings/MyAtoi.java
@@ -25,7 +25,9 @@ public static int myAtoi(String s) {
                     number = "0";
                     break;
                 }
-                if (ch >= '0' && ch <= '9') number += ch;
+                if (ch >= '0' && ch <= '9') {
+                    number += ch;
+                }
             } else if (ch == '-' && !isDigit) {
                 number += "0";
                 negative = true;
diff --git a/src/main/java/com/thealgorithms/strings/Pangram.java b/src/main/java/com/thealgorithms/strings/Pangram.java
index e0989ce86715..01307b28f6c6 100644
--- a/src/main/java/com/thealgorithms/strings/Pangram.java
+++ b/src/main/java/com/thealgorithms/strings/Pangram.java
@@ -29,8 +29,11 @@ public static void main(String[] args) {
     public static boolean isPangramUsingSet(String s) {
         HashSet<Character> alpha = new HashSet<>();
         s = s.trim().toLowerCase();
-        for (int i = 0; i < s.length(); i++)
-            if (s.charAt(i) != ' ') alpha.add(s.charAt(i));
+        for (int i = 0; i < s.length(); i++) {
+            if (s.charAt(i) != ' ') {
+                alpha.add(s.charAt(i));
+            }
+        }
         return alpha.size() == 26;
     }
 
diff --git a/src/main/java/com/thealgorithms/strings/ValidParentheses.java b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
index 947a39da4bde..f4f3761b0495 100644
--- a/src/main/java/com/thealgorithms/strings/ValidParentheses.java
+++ b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
@@ -18,13 +18,19 @@ public static boolean isValid(String s) {
                 stack[head++] = c;
                 break;
             case '}':
-                if (head == 0 || stack[--head] != '{') return false;
+                if (head == 0 || stack[--head] != '{') {
+                    return false;
+                }
                 break;
             case ')':
-                if (head == 0 || stack[--head] != '(') return false;
+                if (head == 0 || stack[--head] != '(') {
+                    return false;
+                }
                 break;
             case ']':
-                if (head == 0 || stack[--head] != '[') return false;
+                if (head == 0 || stack[--head] != '[') {
+                    return false;
+                }
                 break;
             default:
                 throw new IllegalArgumentException("Unexpected character: " + c);
diff --git a/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java b/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java
index 3337f6eeff71..3f33fc17b9b0 100644
--- a/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java
+++ b/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java
@@ -5,7 +5,9 @@ private ZigZagPattern() {
     }
 
     public static String encode(String s, int numRows) {
-        if (numRows < 2 || s.length() < numRows) return s;
+        if (numRows < 2 || s.length() < numRows) {
+            return s;
+        }
         int start = 0;
         int index = 0;
         int height = 1;
@@ -18,11 +20,11 @@ public static String encode(String s, int numRows) {
             boolean bool = true;
             while (pointer < s.length()) {
                 zigZagedArray[index++] = s.charAt(pointer);
-                if (heightSpace == 0)
+                if (heightSpace == 0) {
                     pointer += depthSpace;
-                else if (depthSpace == 0)
+                } else if (depthSpace == 0) {
                     pointer += heightSpace;
-                else if (bool) {
+                } else if (bool) {
                     pointer += depthSpace;
                     bool = false;
                 } else {
diff --git a/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java b/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
index 9bc3b89ced9e..be98fde484fa 100644
--- a/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
@@ -40,21 +40,29 @@ void isFull() {
         buffer.put(generateInt());
         assertFalse(buffer.isFull());
 
-        for (int i = 1; i < BUFFER_SIZE; i++) buffer.put(generateInt());
+        for (int i = 1; i < BUFFER_SIZE; i++) {
+            buffer.put(generateInt());
+        }
         assertTrue(buffer.isFull());
     }
 
     @Test
     void get() {
         assertNull(buffer.get());
-        for (int i = 0; i < 100; i++) buffer.put(i);
-        for (int i = 0; i < BUFFER_SIZE; i++) assertEquals(i, buffer.get());
+        for (int i = 0; i < 100; i++) {
+            buffer.put(i);
+        }
+        for (int i = 0; i < BUFFER_SIZE; i++) {
+            assertEquals(i, buffer.get());
+        }
         assertNull(buffer.get());
     }
 
     @Test
     void put() {
-        for (int i = 0; i < BUFFER_SIZE; i++) assertTrue(buffer.put(generateInt()));
+        for (int i = 0; i < BUFFER_SIZE; i++) {
+            assertTrue(buffer.put(generateInt()));
+        }
         assertFalse(buffer.put(generateInt()));
     }
 
@@ -74,7 +82,9 @@ void concurrentTest() throws InterruptedException {
             while (producerCountDownLatch.getCount() > 0) {
                 int count = (int) producerCountDownLatch.getCount();
                 boolean put = buffer.put(count);
-                while (!put) put = buffer.put(count);
+                while (!put) {
+                    put = buffer.put(count);
+                }
                 producerCountDownLatch.countDown();
             }
         });
@@ -85,7 +95,9 @@ void concurrentTest() throws InterruptedException {
             while (consumerCountDownLatch.getCount() > 0) {
                 int count = (int) consumerCountDownLatch.getCount();
                 Integer item = buffer.get();
-                while (item == null) item = buffer.get();
+                while (item == null) {
+                    item = buffer.get();
+                }
                 resultAtomicArray.set(count - 1, item);
                 consumerCountDownLatch.countDown();
             }
@@ -111,7 +123,9 @@ private int generateInt() {
 
     private void shutDownExecutorSafely(ExecutorService executorService) {
         try {
-            if (!executorService.awaitTermination(1_000, TimeUnit.MILLISECONDS)) executorService.shutdownNow();
+            if (!executorService.awaitTermination(1_000, TimeUnit.MILLISECONDS)) {
+                executorService.shutdownNow();
+            }
         } catch (InterruptedException e) {
             executorService.shutdownNow();
         }
@@ -120,7 +134,9 @@ private void shutDownExecutorSafely(ExecutorService executorService) {
     public List<Integer> getSortedListFrom(AtomicIntegerArray atomicArray) {
         int length = atomicArray.length();
         ArrayList<Integer> result = new ArrayList<>(length);
-        for (int i = 0; i < length; i++) result.add(atomicArray.get(i));
+        for (int i = 0; i < length; i++) {
+            result.add(atomicArray.get(i));
+        }
         result.sort(Comparator.comparingInt(o -> o));
         return result;
     }
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java b/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java
index faa0d0e952f9..7bebf13e9620 100644
--- a/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java
@@ -8,7 +8,9 @@ class LinkedQueueTest {
     @Test
     public void testQue() {
         LinkedQueue<Integer> queue = new LinkedQueue<>();
-        for (int i = 1; i < 5; i++) queue.enqueue(i);
+        for (int i = 1; i < 5; i++) {
+            queue.enqueue(i);
+        }
 
         assertEquals(queue.peekRear(), 4);
         assertEquals(queue.peek(2), 2);
@@ -20,7 +22,9 @@ public void testQue() {
         // iterates over all the elements present
         // as in the form of nodes
         queue.forEach(integer -> {
-            if (element[0]++ != integer) throw new AssertionError();
+            if (element[0]++ != integer) {
+                throw new AssertionError();
+            }
         });
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java
index e8294a323463..7daf8c6313cd 100644
--- a/src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java
@@ -49,12 +49,13 @@ void updateAndGet() {
         int[] arr = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
         LazySegmentTree lazySegmentTree = new LazySegmentTree(arr);
 
-        for (int i = 0; i < 10; i++)
+        for (int i = 0; i < 10; i++) {
             for (int j = i + 1; j < 10; j++) {
                 lazySegmentTree.updateRange(i, j, 1);
                 assertEquals(j - i, lazySegmentTree.getRange(i, j));
                 lazySegmentTree.updateRange(i, j, -1);
                 assertEquals(0, lazySegmentTree.getRange(i, j));
             }
+        }
     }
 }
diff --git a/src/test/java/com/thealgorithms/io/BufferedReaderTest.java b/src/test/java/com/thealgorithms/io/BufferedReaderTest.java
index baccf319d15e..891c3066058e 100644
--- a/src/test/java/com/thealgorithms/io/BufferedReaderTest.java
+++ b/src/test/java/com/thealgorithms/io/BufferedReaderTest.java
@@ -54,7 +54,9 @@ public void testMixes() throws IOException {
         assertEquals(reader.read(), 'l'); // third letter
         assertEquals(reader.peek(1), 'o'); // fourth letter
 
-        for (int i = 0; i < 6; i++) reader.read();
+        for (int i = 0; i < 6; i++) {
+            reader.read();
+        }
         try {
             System.out.println((char) reader.peek(4));
         } catch (Exception ignored) {
diff --git a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
index 90910d511ca0..6307b8e19b5d 100644
--- a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
+++ b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
@@ -117,7 +117,9 @@ public void testWithLargeValues() {
     @Test
     public void testWithLargeCountOfValues() {
         var stream = new MedianOfRunningArrayInteger();
-        for (int i = 1; i <= 1000; i++) stream.insert(i);
+        for (int i = 1; i <= 1000; i++) {
+            stream.insert(i);
+        }
         assertEquals(500, stream.median());
     }
 

From cdb3affdd9ac4b8c7ccf4c55b05f6914bb9e73d6 Mon Sep 17 00:00:00 2001
From: Samuel Facchinello <4256795+samuelfac@users.noreply.github.com>
Date: Fri, 14 Jun 2024 16:57:30 +0200
Subject: [PATCH 0202/1338] style: enable `AvoidNestedBlocks` in checkstyle
 (#5228)

* enable style AvoidNestedBlocks

* refactor after enable style AvoidNestedBlocks

* fix clang

* fix checkstyle

* fix pmd

---------

Co-authored-by: Samuel Facchinello <samuel.facchinello@piksel.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 checkstyle.xml                                |  2 +-
 .../datastructures/hashmap/hashing/Main.java  | 19 ++---
 .../hashmap/hashing/MainCuckooHashing.java    | 31 ++++---
 .../com/thealgorithms/maths/MatrixUtil.java   | 84 +------------------
 .../java/com/thealgorithms/misc/Sort012D.java | 11 ++-
 .../java/com/thealgorithms/sorts/DNFSort.java |  8 +-
 .../thealgorithms/maths/MatrixUtilTest.java   | 79 +++++++++++++++++
 7 files changed, 117 insertions(+), 117 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/MatrixUtilTest.java

diff --git a/checkstyle.xml b/checkstyle.xml
index 48c8a4f1f377..45431b39897a 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -152,7 +152,7 @@
 
     <!-- Checks for blocks. You know, those {}'s         -->
     <!-- See https://checkstyle.org/checks/blocks/index.html -->
-    <!-- TODO <module name="AvoidNestedBlocks"/> -->
+    <module name="AvoidNestedBlocks"/>
     <!-- TODO <module name="EmptyBlock"/> -->
     <!-- TODO <module name="LeftCurly"/> -->
     <module name="NeedBraces"/>
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
index 082fd4b5ab2a..4d9b33b115c7 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
@@ -23,31 +23,30 @@ public static void main(String[] args) {
             choice = scan.nextInt();
 
             switch (choice) {
-            case 1: {
+            case 1:
                 System.out.println("Enter the Key: ");
                 key = scan.nextInt();
                 h.insertHash(key);
                 break;
-            }
-            case 2: {
+
+            case 2:
                 System.out.println("Enter the Key delete:  ");
                 key = scan.nextInt();
                 h.deleteHash(key);
                 break;
-            }
-            case 3: {
+
+            case 3:
                 System.out.println("Print table");
                 h.displayHashtable();
                 break;
-            }
-            case 4: {
+
+            case 4:
                 scan.close();
                 return;
-            }
-            default: {
+
+            default:
                 throw new IllegalArgumentException("Unexpected value: " + choice);
             }
-            }
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
index 5a4a56e9b37d..ff4c69a5ec78 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
@@ -27,45 +27,44 @@ public static void main(String[] args) {
             choice = scan.nextInt();
 
             switch (choice) {
-            case 1: {
+            case 1:
                 System.out.println("Enter the Key: ");
                 key = scan.nextInt();
                 h.insertKey2HashTable(key);
                 break;
-            }
-            case 2: {
+
+            case 2:
                 System.out.println("Enter the Key delete:  ");
                 key = scan.nextInt();
                 h.deleteKeyFromHashTable(key);
                 break;
-            }
-            case 3: {
+
+            case 3:
                 System.out.println("Print table:\n");
                 h.displayHashtable();
                 break;
-            }
-            case 4: {
+
+            case 4:
                 scan.close();
                 return;
-            }
-            case 5: {
+
+            case 5:
                 System.out.println("Enter the Key to find and print:  ");
                 key = scan.nextInt();
                 System.out.println("Key: " + key + " is at index: " + h.findKeyInTable(key) + "\n");
                 break;
-            }
-            case 6: {
+
+            case 6:
                 System.out.printf("Load factor is: %.2f%n", h.checkLoadFactor());
                 break;
-            }
-            case 7: {
+
+            case 7:
                 h.reHashTableIncreasesTableSize();
                 break;
-            }
-            default: {
+
+            default:
                 throw new IllegalArgumentException("Unexpected value: " + choice);
             }
-            }
         }
     }
 }
diff --git a/src/main/java/com/thealgorithms/maths/MatrixUtil.java b/src/main/java/com/thealgorithms/maths/MatrixUtil.java
index 0759853d61a9..7e462f92e185 100644
--- a/src/main/java/com/thealgorithms/maths/MatrixUtil.java
+++ b/src/main/java/com/thealgorithms/maths/MatrixUtil.java
@@ -1,8 +1,6 @@
 package com.thealgorithms.maths;
 
 import java.math.BigDecimal;
-import java.util.Arrays;
-import java.util.Objects;
 import java.util.Optional;
 import java.util.function.BiFunction;
 import java.util.stream.IntStream;
@@ -15,19 +13,19 @@ public final class MatrixUtil {
     private MatrixUtil() {
     }
 
-    public static boolean isValid(final BigDecimal[][] matrix) {
+    private static boolean isValid(final BigDecimal[][] matrix) {
         return matrix != null && matrix.length > 0 && matrix[0].length > 0;
     }
 
-    public static boolean hasEqualSizes(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2) {
+    private static boolean hasEqualSizes(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2) {
         return (isValid(matrix1) && isValid(matrix2) && matrix1.length == matrix2.length && matrix1[0].length == matrix2[0].length);
     }
 
-    public static boolean canMultiply(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2) {
+    private static boolean canMultiply(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2) {
         return (isValid(matrix1) && isValid(matrix2) && matrix1[0].length == matrix2.length);
     }
 
-    public static Optional<BigDecimal[][]> operate(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2, final BiFunction<BigDecimal, BigDecimal, BigDecimal> operation) {
+    private static Optional<BigDecimal[][]> operate(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2, final BiFunction<BigDecimal, BigDecimal, BigDecimal> operation) {
         if (!hasEqualSizes(matrix1, matrix2)) {
             return Optional.empty();
         }
@@ -82,78 +80,4 @@ public static Optional<BigDecimal[][]> multiply(final BigDecimal[][] matrix1, fi
 
         return Optional.of(result);
     }
-
-    public static void assertThat(final BigDecimal[][] actual, final BigDecimal[][] expected) {
-        if (!Objects.deepEquals(actual, expected)) {
-            throw new AssertionError(String.format("expected=%s but was actual=%s", Arrays.deepToString(expected), Arrays.deepToString(actual)));
-        }
-    }
-
-    public static void main(final String[] args) {
-        {
-            final BigDecimal[][] matrix1 = {
-                {new BigDecimal(3), new BigDecimal(2)},
-                {new BigDecimal(0), new BigDecimal(1)},
-            };
-
-            final BigDecimal[][] matrix2 = {
-                {new BigDecimal(1), new BigDecimal(3)},
-                {new BigDecimal(2), new BigDecimal(0)},
-            };
-
-            final BigDecimal[][] actual = add(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
-
-            final BigDecimal[][] expected = {
-                {new BigDecimal(4), new BigDecimal(5)},
-                {new BigDecimal(2), new BigDecimal(1)},
-            };
-
-            assertThat(actual, expected);
-        }
-
-        {
-            final BigDecimal[][] matrix1 = {
-                {new BigDecimal(1), new BigDecimal(4)},
-                {new BigDecimal(5), new BigDecimal(6)},
-            };
-
-            final BigDecimal[][] matrix2 = {
-                {new BigDecimal(2), new BigDecimal(0)},
-                {new BigDecimal(-2), new BigDecimal(-3)},
-            };
-
-            final BigDecimal[][] actual = subtract(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
-
-            final BigDecimal[][] expected = {
-                {new BigDecimal(-1), new BigDecimal(4)},
-                {new BigDecimal(7), new BigDecimal(9)},
-            };
-
-            assertThat(actual, expected);
-        }
-
-        {
-            final BigDecimal[][] matrix1 = {
-                {new BigDecimal(1), new BigDecimal(2), new BigDecimal(3)},
-                {new BigDecimal(4), new BigDecimal(5), new BigDecimal(6)},
-                {new BigDecimal(7), new BigDecimal(8), new BigDecimal(9)},
-            };
-
-            final BigDecimal[][] matrix2 = {
-                {new BigDecimal(1), new BigDecimal(2)},
-                {new BigDecimal(3), new BigDecimal(4)},
-                {new BigDecimal(5), new BigDecimal(6)},
-            };
-
-            final BigDecimal[][] actual = multiply(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
-
-            final BigDecimal[][] expected = {
-                {new BigDecimal(22), new BigDecimal(28)},
-                {new BigDecimal(49), new BigDecimal(64)},
-                {new BigDecimal(76), new BigDecimal(100)},
-            };
-
-            assertThat(actual, expected);
-        }
-    }
 }
diff --git a/src/main/java/com/thealgorithms/misc/Sort012D.java b/src/main/java/com/thealgorithms/misc/Sort012D.java
index febe13f4fec3..706e877e40c1 100644
--- a/src/main/java/com/thealgorithms/misc/Sort012D.java
+++ b/src/main/java/com/thealgorithms/misc/Sort012D.java
@@ -33,28 +33,27 @@ public static void sort012(int[] a) {
         int temp;
         while (mid <= h) {
             switch (a[mid]) {
-            case 0: {
+            case 0:
                 temp = a[l];
                 a[l] = a[mid];
                 a[mid] = temp;
                 l++;
                 mid++;
                 break;
-            }
+
             case 1:
                 mid++;
                 break;
-            case 2: {
+            case 2:
                 temp = a[mid];
                 a[mid] = a[h];
                 a[h] = temp;
                 h--;
                 break;
-            }
-            default: {
+
+            default:
                 throw new IllegalArgumentException("Unexpected value: " + a[mid]);
             }
-            }
         }
         System.out.println("the Sorted array is ");
         for (int i = 0; i < a.length; i++) {
diff --git a/src/main/java/com/thealgorithms/sorts/DNFSort.java b/src/main/java/com/thealgorithms/sorts/DNFSort.java
index 50ba8c89715b..4b1e913cf3e0 100644
--- a/src/main/java/com/thealgorithms/sorts/DNFSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DNFSort.java
@@ -13,24 +13,24 @@ static void sort012(int[] a, int arrSize) {
         int temp;
         while (mid <= high) {
             switch (a[mid]) {
-            case 0: {
+            case 0:
                 temp = a[low];
                 a[low] = a[mid];
                 a[mid] = temp;
                 low++;
                 mid++;
                 break;
-            }
+
             case 1:
                 mid++;
                 break;
-            case 2: {
+            case 2:
                 temp = a[mid];
                 a[mid] = a[high];
                 a[high] = temp;
                 high--;
                 break;
-            }
+
             default:
                 throw new IllegalArgumentException("Unexpected value: " + a[mid]);
             }
diff --git a/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java b/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java
new file mode 100644
index 000000000000..f61ebe6a26cc
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java
@@ -0,0 +1,79 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.math.BigDecimal;
+import java.util.Objects;
+import org.junit.jupiter.api.Test;
+
+class MatrixUtilTest {
+
+    @Test
+    void add() {
+        final BigDecimal[][] matrix1 = {
+            {new BigDecimal(3), new BigDecimal(2)},
+            {BigDecimal.ZERO, BigDecimal.ONE},
+        };
+
+        final BigDecimal[][] matrix2 = {
+            {BigDecimal.ONE, new BigDecimal(3)},
+            {new BigDecimal(2), BigDecimal.ZERO},
+        };
+
+        final BigDecimal[][] actual = MatrixUtil.add(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
+
+        final BigDecimal[][] expected = {
+            {new BigDecimal(4), new BigDecimal(5)},
+            {new BigDecimal(2), BigDecimal.ONE},
+        };
+
+        assertTrue(Objects.deepEquals(actual, expected));
+    }
+    @Test
+    void subtract() {
+        final BigDecimal[][] matrix1 = {
+            {BigDecimal.ONE, new BigDecimal(4)},
+            {new BigDecimal(5), new BigDecimal(6)},
+        };
+
+        final BigDecimal[][] matrix2 = {
+            {new BigDecimal(2), BigDecimal.ZERO},
+            {new BigDecimal(-2), new BigDecimal(-3)},
+        };
+
+        final BigDecimal[][] actual = MatrixUtil.subtract(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
+
+        final BigDecimal[][] expected = {
+            {new BigDecimal(-1), new BigDecimal(4)},
+            {new BigDecimal(7), new BigDecimal(9)},
+        };
+
+        assertTrue(Objects.deepEquals(actual, expected));
+    }
+
+    @Test
+    void multiply() {
+
+        final BigDecimal[][] matrix1 = {
+            {BigDecimal.ONE, new BigDecimal(2), new BigDecimal(3)},
+            {new BigDecimal(4), new BigDecimal(5), new BigDecimal(6)},
+            {new BigDecimal(7), new BigDecimal(8), new BigDecimal(9)},
+        };
+
+        final BigDecimal[][] matrix2 = {
+            {BigDecimal.ONE, new BigDecimal(2)},
+            {new BigDecimal(3), new BigDecimal(4)},
+            {new BigDecimal(5), new BigDecimal(6)},
+        };
+
+        final BigDecimal[][] actual = MatrixUtil.multiply(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
+
+        final BigDecimal[][] expected = {
+            {new BigDecimal(22), new BigDecimal(28)},
+            {new BigDecimal(49), new BigDecimal(64)},
+            {new BigDecimal(76), new BigDecimal(100)},
+        };
+
+        assertTrue(Objects.deepEquals(actual, expected));
+    }
+}

From c7ee0e73c2a04109daae88200fe17dfc3aa52bef Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 15 Jun 2024 11:02:09 +0200
Subject: [PATCH 0203/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-surefire-plugin from 3.2.5 to 3.3.0 (#5234)

Chore(deps): bump org.apache.maven.plugins:maven-surefire-plugin

Bumps [org.apache.maven.plugins:maven-surefire-plugin](https://github.com/apache/maven-surefire) from 3.2.5 to 3.3.0.
- [Release notes](https://github.com/apache/maven-surefire/releases)
- [Commits](https://github.com/apache/maven-surefire/compare/surefire-3.2.5...surefire-3.3.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-surefire-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 98771e184caa..a3a2b39e24de 100644
--- a/pom.xml
+++ b/pom.xml
@@ -63,7 +63,7 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.2.5</version>
+                <version>3.3.0</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>

From 9973b8efc86cb31eb741e94646ca962528c1f17c Mon Sep 17 00:00:00 2001
From: Samuel Facchinello <4256795+samuelfac@users.noreply.github.com>
Date: Mon, 17 Jun 2024 22:55:20 +0200
Subject: [PATCH 0204/1338] refactor: redesign `StringMatchFiniteAutomata`
 (#5222)

* refactor

* add test

* fix clang

* fix pmd

* remove main method

* refactor searchPattern with private class

* fix checkstyle

* Update src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* fix clang

* tests: add more test cases

---------

Co-authored-by: Samuel Facchinello <samuel.facchinello@piksel.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../others/StringMatchFiniteAutomata.java     | 141 ++++++++++++------
 .../others/StringMatchFiniteAutomataTest.java |  23 +++
 2 files changed, 116 insertions(+), 48 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java

diff --git a/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java b/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
index 22979e59b555..561845f41a07 100644
--- a/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
+++ b/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
@@ -1,80 +1,125 @@
 package com.thealgorithms.others;
 
+import java.util.Set;
+import java.util.TreeSet;
+
 /**
- * @author Prateek Kumar Oraon (https://github.com/prateekKrOraon)
+ * A class to perform string matching using <a href="https://en.wikipedia.org/wiki/Finite-state_machine">finite automata</a>.
+ *
+ * @author <a href="https://github.com/prateekKrOraon">Prateek Kumar Oraon</a>
  */
-import java.util.Scanner;
-
-// An implementation of string matching using finite automata
 public final class StringMatchFiniteAutomata {
-    private StringMatchFiniteAutomata() {
-    }
-
-    public static final int CHARS = 256;
-    public static int[][] fa;
-    public static Scanner scanner = null;
-
-    public static void main(String[] args) {
-        scanner = new Scanner(System.in);
-        System.out.println("Enter String");
-        String text = scanner.nextLine();
-        System.out.println("Enter pattern");
-        String pat = scanner.nextLine();
 
-        searchPat(text, pat);
+    // Constants
+    private static final int CHARS = Character.MAX_VALUE + 1; // Total number of characters in the input alphabet
 
-        scanner.close();
+    // Private constructor to prevent instantiation
+    private StringMatchFiniteAutomata() {
     }
 
-    public static void searchPat(String text, String pat) {
-        int m = pat.length();
-        int n = text.length();
-
-        fa = new int[m + 1][CHARS];
-
-        computeFA(pat, m, fa);
-
-        int state = 0;
-        for (int i = 0; i < n; i++) {
-            state = fa[state][text.charAt(i)];
-
-            if (state == m) {
-                System.out.println("Pattern found at index " + (i - m + 1));
+    /**
+     * Searches for the pattern in the given text using finite automata.
+     *
+     * @param text    The text to search within.
+     * @param pattern The pattern to search for.
+     */
+    public static Set<Integer> searchPattern(final String text, final String pattern) {
+        final var stateTransitionTable = computeStateTransitionTable(pattern);
+        FiniteAutomata finiteAutomata = new FiniteAutomata(stateTransitionTable);
+
+        Set<Integer> indexFound = new TreeSet<>();
+        for (int i = 0; i < text.length(); i++) {
+            finiteAutomata.consume(text.charAt(i));
+
+            if (finiteAutomata.getState() == pattern.length()) {
+                indexFound.add(i - pattern.length() + 1);
             }
         }
+        return indexFound;
     }
 
-    // Computes finite automata for the pattern
-    public static void computeFA(String pat, int m, int[][] fa) {
-        for (int state = 0; state <= m; ++state) {
+    /**
+     * Computes the finite automata table for the given pattern.
+     *
+     * @param pattern The pattern to preprocess.
+     * @return The state transition table.
+     */
+    private static int[][] computeStateTransitionTable(final String pattern) {
+        final int patternLength = pattern.length();
+        int[][] stateTransitionTable = new int[patternLength + 1][CHARS];
+
+        for (int state = 0; state <= patternLength; ++state) {
             for (int x = 0; x < CHARS; ++x) {
-                fa[state][x] = getNextState(pat, m, state, x);
+                stateTransitionTable[state][x] = getNextState(pattern, patternLength, state, x);
             }
         }
+
+        return stateTransitionTable;
     }
 
-    public static int getNextState(String pat, int m, int state, int x) {
-        // if current state is less than length of pattern
-        // and input character of pattern matches the character in the alphabet
-        // then automata goes to next state
-        if (state < m && x == pat.charAt(state)) {
+    /**
+     * Gets the next state for the finite automata.
+     *
+     * @param pattern       The pattern being matched.
+     * @param patternLength The length of the pattern.
+     * @param state         The current state.
+     * @param x             The current character from the input alphabet.
+     * @return The next state.
+     */
+    private static int getNextState(final String pattern, final int patternLength, final int state, final int x) {
+        // If the current state is less than the length of the pattern
+        // and the character matches the pattern character, go to the next state
+        if (state < patternLength && x == pattern.charAt(state)) {
             return state + 1;
         }
 
+        // Check for the highest prefix which is also a suffix
         for (int ns = state; ns > 0; ns--) {
-            if (pat.charAt(ns - 1) == x) {
+            if (pattern.charAt(ns - 1) == x) {
+                boolean match = true;
                 for (int i = 0; i < ns - 1; i++) {
-                    if (pat.charAt(i) != pat.charAt(state - ns + i + 1)) {
+                    if (pattern.charAt(i) != pattern.charAt(state - ns + i + 1)) {
+                        match = false;
                         break;
                     }
-
-                    if (i == ns - 1) {
-                        return ns;
-                    }
+                }
+                if (match) {
+                    return ns;
                 }
             }
         }
 
+        // If no prefix which is also a suffix is found, return 0
         return 0;
     }
+
+    /**
+     * A class representing the finite automata for pattern matching.
+     */
+    private static final class FiniteAutomata {
+        private int state = 0;
+        private final int[][] stateTransitionTable;
+
+        private FiniteAutomata(int[][] stateTransitionTable) {
+            this.stateTransitionTable = stateTransitionTable;
+        }
+
+        /**
+         * Consumes an input character and transitions to the next state.
+         *
+         * @param input The input character.
+         */
+        private void consume(final char input) {
+            state = stateTransitionTable[state][input];
+        }
+
+        /**
+         * Gets the current state of the finite automata.
+         *
+         * @return The current state.
+         */
+        private int getState() {
+            return state;
+        }
+    }
 }
diff --git a/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java b/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java
new file mode 100644
index 000000000000..6e1947b76a38
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Set;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class StringMatchFiniteAutomataTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void searchPattern(String text, String pattern, Set<Integer> expectedOutput) {
+        assertEquals(expectedOutput, StringMatchFiniteAutomata.searchPattern(text, pattern));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of("abcbcabc", "abc", Set.of(0, 5)), Arguments.of("", "abc", Set.of()), Arguments.of("", "", Set.of()), Arguments.of("a", "b", Set.of()), Arguments.of("a", "a", Set.of(0)), Arguments.of("abcdabcabcabcd", "abcd", Set.of(0, 10)), Arguments.of("abc", "bcd", Set.of()),
+            Arguments.of("abcdefg", "xyz", Set.of()), Arguments.of("abcde", "", Set.of(1, 2, 3, 4, 5)), Arguments.of("abcabcabc", "abc", Set.of(0, 3, 6)), Arguments.of("abcabcabc", "abcabcabc", Set.of(0)), Arguments.of("aaabbbaaa", "aaa", Set.of(0, 6)), Arguments.of("abcdefg", "efg", Set.of(4)));
+    }
+}

From 39e065437c4c70d9d99c0de3343a980f423d5bc5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 18 Jun 2024 08:40:46 +0200
Subject: [PATCH 0205/1338] Chore(deps): bump gitpod/workspace-java-21 from
 2024-06-10-10-39-01 to 2024-06-17-10-03-09 (#5235)

Chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2024-06-10-10-39-01 to 2024-06-17-10-03-09.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 6ca2b97e8442..0718384d33ff 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-06-10-10-39-01
+FROM gitpod/workspace-java-21:2024-06-17-10-03-09
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 74e51990c1f640a839f0fcc695d4faefce48d32f Mon Sep 17 00:00:00 2001
From: Samuel Facchinello <4256795+samuelfac@users.noreply.github.com>
Date: Tue, 18 Jun 2024 19:34:22 +0200
Subject: [PATCH 0206/1338] style: enable `InvalidJavadocPosition` in
 checkstyle (#5237)

enable style InvalidJavadocPosition

Co-authored-by: Samuel Facchinello <samuel.facchinello@piksel.com>
---
 checkstyle.xml                                |  2 +-
 .../AllPathsFromSourceToTarget.java           | 14 ++--
 .../graphs/HamiltonianCycle.java              | 18 ++---
 .../datastructures/graphs/KahnsAlgorithm.java |  3 -
 .../datastructures/graphs/Kosaraju.java       | 71 ++++++++---------
 .../graphs/TarjansAlgorithm.java              | 79 +++++++++----------
 .../datastructures/lists/RandomNode.java      | 60 ++++++--------
 .../lists/SinglyLinkedList.java               |  9 +--
 .../trees/CeilInBinarySearchTree.java         |  2 -
 .../datastructures/trees/TrieImp.java         |  6 +-
 .../dynamicprogramming/CatalanNumber.java     |  9 +--
 .../CountFriendsPairing.java                  | 18 ++---
 .../dynamicprogramming/EditDistance.java      |  3 +-
 .../dynamicprogramming/KadaneAlgorithm.java   | 24 +++---
 .../dynamicprogramming/NewManShanksPrime.java | 13 ++-
 .../dynamicprogramming/RegexMatching.java     |  2 -
 .../dynamicprogramming/SubsetCount.java       |  6 +-
 .../maths/AutomorphicNumber.java              |  6 +-
 .../com/thealgorithms/maths/DigitalRoot.java  | 20 ++---
 .../thealgorithms/maths/FastInverseSqrt.java  | 45 +++++------
 .../com/thealgorithms/maths/FrizzyNumber.java | 11 +--
 .../thealgorithms/maths/JosephusProblem.java  |  3 -
 .../thealgorithms/maths/PascalTriangle.java   |  6 +-
 .../others/BankersAlgorithm.java              |  4 +-
 .../com/thealgorithms/others/Dijkstra.java    |  9 +--
 .../others/MemoryManagementAlgorithms.java    |  4 +-
 .../com/thealgorithms/others/RabinKarp.java   |  9 ++-
 .../others/RotateMatrixBy90Degrees.java       |  3 +-
 .../com/thealgorithms/sorts/LinkListSort.java | 33 ++++----
 .../com/thealgorithms/strings/Anagrams.java   | 36 ++++-----
 .../NumbersDifferentSignsTest.java            | 10 +--
 .../graphs/BoruvkaAlgorithmTest.java          |  6 +-
 .../lists/QuickSortLinkedListTest.java        | 10 +--
 .../lists/ReverseKGroupTest.java              | 10 +--
 .../lists/RotateSinglyLinkedListsTest.java    |  9 +--
 .../PreemptivePrioritySchedulingTest.java     |  9 +--
 .../thealgorithms/strings/WordLadderTest.java | 38 ++++-----
 37 files changed, 273 insertions(+), 347 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 45431b39897a..af5e3527e32f 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -99,7 +99,7 @@
 
     <!-- Checks for Javadoc comments.                     -->
     <!-- See https://checkstyle.org/checks/javadoc/index.html -->
-    <!-- TODO <module name="InvalidJavadocPosition"/> -->
+    <module name="InvalidJavadocPosition"/>
     <!-- TODO <module name="JavadocMethod"/> -->
     <!-- TODO <module name="JavadocType"/> -->
     <!-- TODO <module name="JavadocVariable"/> -->
diff --git a/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java b/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
index a21f8c05f292..6f93b704ffb2 100644
--- a/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
+++ b/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
@@ -1,16 +1,14 @@
-/**
- * Author : Siddhant Swarup Mallick
- * Github : https://github.com/siddhant2002
- */
-
-/** Program description - To find all possible paths from source to destination*/
-
-/**Wikipedia link -> https://en.wikipedia.org/wiki/Shortest_path_problem */
 package com.thealgorithms.backtracking;
 
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Program description - To find all possible paths from source to destination
+ * <a href="https://en.wikipedia.org/wiki/Shortest_path_problem">Wikipedia</a>
+ *
+ * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
+ */
 public class AllPathsFromSourceToTarget {
 
     // No. of vertices in graph
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java b/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
index 65483eeeb65c..f12e3892b1b2 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
@@ -2,9 +2,9 @@
 
 /**
  * Java program for Hamiltonian Cycle
- * (https://en.wikipedia.org/wiki/Hamiltonian_path)
+ * <a href="https://en.wikipedia.org/wiki/Hamiltonian_path">wikipedia</a>
  *
- * @author Akshay Dubey (https://github.com/itsAkshayDubey)
+ * @author  <a href="https://github.com/itsAkshayDubey">Akshay Dubey</a>
  */
 public class HamiltonianCycle {
 
@@ -58,31 +58,31 @@ public boolean isPathFound(int vertex) {
             return true;
         }
 
-        /** all vertices selected but last vertex not linked to 0 **/
+        /* all vertices selected but last vertex not linked to 0 **/
         if (this.pathCount == this.vertex) {
             return false;
         }
 
         for (int v = 0; v < this.vertex; v++) {
-            /** if connected **/
+            /* if connected **/
             if (this.graph[vertex][v] == 1) {
-                /** add to path **/
+                /* add to path **/
                 this.cycle[this.pathCount++] = v;
 
-                /** remove connection **/
+                /* remove connection **/
                 this.graph[vertex][v] = 0;
                 this.graph[v][vertex] = 0;
 
-                /** if vertex not already selected solve recursively **/
+                /* if vertex not already selected solve recursively **/
                 if (!isPresent(v)) {
                     return isPathFound(v);
                 }
 
-                /** restore connection **/
+                /* restore connection **/
                 this.graph[vertex][v] = 1;
                 this.graph[v][vertex] = 1;
 
-                /** remove path **/
+                /* remove path **/
                 this.cycle[--this.pathCount] = -1;
             }
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
index be83ea32f496..d5035cf625a6 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
@@ -8,9 +8,6 @@
 import java.util.Queue;
 import java.util.Set;
 
-/**
- * An algorithm that sorts a graph in toplogical order.
- */
 /**
  * A class that represents the adjaceny list of a graph
  */
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java b/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java
index 7c0c0b2bee78..c5f15839f997 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java
@@ -6,53 +6,50 @@
 
 /**
  * Java program that implements Kosaraju Algorithm.
- * @author Shivanagouda S A (https://github.com/shivu2002a)
- *
- */
-
-/**
+ * @author <a href="https://github.com/shivu2002a">Shivanagouda S A</a>
+ * <p>
  * Kosaraju algorithm is a linear time algorithm to find the strongly connected components of a
-   directed graph, which, from here onwards will be referred by SCC. It leverages the fact that the
- transpose graph (same graph with all the edges reversed) has exactly the same SCCs as the original
- graph.
+directed graph, which, from here onwards will be referred by SCC. It leverages the fact that the
+transpose graph (same graph with all the edges reversed) has exactly the same SCCs as the original
+graph.
 
  * A graph is said to be strongly connected if every vertex is reachable from every other vertex.
-   The SCCs of a directed graph form a partition into subgraphs that are themselves strongly
- connected. Single node is always a SCC.
+The SCCs of a directed graph form a partition into subgraphs that are themselves strongly
+connected. Single node is always a SCC.
 
  * Example:
 
-    0 <--- 2 -------> 3 -------- > 4 ---- > 7
-    |     ^                      | ^       ^
-    |    /                       |  \     /
-    |   /                        |   \   /
-    v  /                         v    \ /
-    1                            5 --> 6
+0 <--- 2 -------> 3 -------- > 4 ---- > 7
+|     ^                      | ^       ^
+|    /                       |  \     /
+|   /                        |   \   /
+v  /                         v    \ /
+1                            5 --> 6
 
-    For the above graph, the SCC list goes as follows:
-    0, 1, 2
-    3
-    4, 5, 6
-    7
+For the above graph, the SCC list goes as follows:
+0, 1, 2
+3
+4, 5, 6
+7
 
-    We can also see that order of the nodes in an SCC doesn't matter since they are in cycle.
+We can also see that order of the nodes in an SCC doesn't matter since they are in cycle.
 
- {@summary}
+{@summary}
  * Kosaraju Algorithm:
-    1. Perform DFS traversal of the graph. Push node to stack before returning. This gives edges
- sorted by lowest finish time.
-    2. Find the transpose graph by reversing the edges.
-    3. Pop nodes one by one from the stack and again to DFS on the modified graph.
-
-    The transpose graph of the above graph:
-     0 ---> 2 <------- 3 <------- 4 <------ 7
-    ^     /                      ^ \       /
-    |    /                       |  \     /
-    |   /                        |   \   /
-    |  v                         |    v v
-    1                            5 <--- 6
-
-    We can observe that this graph has the same SCC as that of original graph.
+1. Perform DFS traversal of the graph. Push node to stack before returning. This gives edges
+sorted by lowest finish time.
+2. Find the transpose graph by reversing the edges.
+3. Pop nodes one by one from the stack and again to DFS on the modified graph.
+
+The transpose graph of the above graph:
+0 ---> 2 <------- 3 <------- 4 <------ 7
+^     /                      ^ \       /
+|    /                       |  \     /
+|   /                        |   \   /
+|  v                         |    v v
+1                            5 <--- 6
+
+We can observe that this graph has the same SCC as that of original graph.
 
  */
 
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
index 336e375f7d4e..de50044256c6 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
@@ -6,51 +6,48 @@
 
 /**
  * Java program that implements Tarjan's Algorithm.
- * @author Shivanagouda S A (https://github.com/shivu2002a)
- *
- */
-
-/**
+ * @author <a href="https://github.com/shivu2002a">Shivanagouda S A</a>
+ * <p>
  * Tarjan's algorithm is a linear time algorithm to find the strongly connected components of a
-   directed graph, which, from here onwards will be referred as SCC.
+directed graph, which, from here onwards will be referred as SCC.
 
  * A graph is said to be strongly connected if every vertex is reachable from every other vertex.
-   The SCCs of a directed graph form a partition into subgraphs that are themselves strongly
- connected. Single node is always a SCC.
+The SCCs of a directed graph form a partition into subgraphs that are themselves strongly
+connected. Single node is always a SCC.
 
  * Example:
-    0 --------> 1 -------> 3 --------> 4
-    ^          /
-    |         /
-    |        /
-    |       /
-    |      /
-    |     /
-    |    /
-    |   /
-    |  /
-    | /
-    |V
-    2
-
-    For the above graph, the SCC list goes as follows:
-    1, 2, 0
-    3
-    4
-
-    We can also see that order of the nodes in an SCC doesn't matter since they are in cycle.
-
- {@summary}
-    Tarjan's Algorithm:
-    * DFS search produces a DFS tree
-    * Strongly Connected Components form subtrees of the DFS tree.
-    * If we can find the head of these subtrees, we can get all the nodes in that subtree (including
- the head) and that will be one SCC.
-    * There is no back edge from one SCC to another (here can be cross edges, but they will not be
- used).
-
-    * Kosaraju Algorithm aims at doing the same but uses two DFS traversalse whereas Tarjan’s
- algorithm does the same in a single DFS, which leads to much lower constant factors in the latter.
+0 --------> 1 -------> 3 --------> 4
+^          /
+|         /
+|        /
+|       /
+|      /
+|     /
+|    /
+|   /
+|  /
+| /
+|V
+2
+
+For the above graph, the SCC list goes as follows:
+1, 2, 0
+3
+4
+
+We can also see that order of the nodes in an SCC doesn't matter since they are in cycle.
+
+{@summary}
+Tarjan's Algorithm:
+ * DFS search produces a DFS tree
+ * Strongly Connected Components form subtrees of the DFS tree.
+ * If we can find the head of these subtrees, we can get all the nodes in that subtree (including
+the head) and that will be one SCC.
+ * There is no back edge from one SCC to another (here can be cross edges, but they will not be
+used).
+
+ * Kosaraju Algorithm aims at doing the same but uses two DFS traversalse whereas Tarjan’s
+algorithm does the same in a single DFS, which leads to much lower constant factors in the latter.
 
  */
 public class TarjansAlgorithm {
@@ -58,7 +55,7 @@ public class TarjansAlgorithm {
     // Timer for tracking lowtime and insertion time
     private int time;
 
-    private List<List<Integer>> sccList = new ArrayList<List<Integer>>();
+    private final List<List<Integer>> sccList = new ArrayList<List<Integer>>();
 
     public List<List<Integer>> stronglyConnectedComponents(int v, List<List<Integer>> graph) {
 
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/RandomNode.java b/src/main/java/com/thealgorithms/datastructures/lists/RandomNode.java
index 7318b8027f8c..dac88dd9f241 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/RandomNode.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/RandomNode.java
@@ -1,43 +1,37 @@
-/**
- * Author : Suraj Kumar
- * Github : https://github.com/skmodi649
- */
+package com.thealgorithms.datastructures.lists;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
 
 /**
+ * @author <a href="https://github.com/skmodi649">Suraj Kumar</a>
+ * <p>
  * PROBLEM DESCRIPTION :
  * There is a single linked list and we are supposed to find a random node in the given linked list
- */
-
-/**
+ * <p>
  * ALGORITHM :
  * Step 1 : START
  * Step 2 : Create an arraylist of type integer
  * Step 3 : Declare an integer type variable for size and linked list type for head
  * Step 4 : We will use two methods, one for traversing through the linked list using while loop and
  * also increase the size by 1
- *
+ * <p>
  * (a) RandomNode(head)
  * (b) run a while loop till null;
  * (c) add the value to arraylist;
  * (d) increase the size;
- *
+ * <p>
  * Step 5 : Now use another method for getting random values using Math.random() and return the
  * value present in arraylist for the calculated index Step 6 : Now in main() method we will simply
  * insert nodes in the linked list and then call the appropriate method and then print the random
  * node generated Step 7 : STOP
  */
-
-package com.thealgorithms.datastructures.lists;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Random;
-
 public class RandomNode {
 
-    private List<Integer> list;
+    private final List<Integer> list;
     private int size;
-    private static Random rand = new Random();
+    private static final Random RAND = new Random();
 
     static class ListNode {
 
@@ -63,10 +57,23 @@ public RandomNode(ListNode head) {
     }
 
     public int getRandom() {
-        int index = rand.nextInt(size);
+        int index = RAND.nextInt(size);
         return list.get(index);
     }
 
+    /**
+     * OUTPUT :
+     * First output :
+     * Random Node : 25
+     * Second output :
+     * Random Node : 78
+     * Time Complexity : O(n)
+     * Auxiliary Space Complexity : O(1)
+     * Time Complexity : O(n)
+     * Auxiliary Space Complexity : O(1)
+     * Time Complexity : O(n)
+     * Auxiliary Space Complexity : O(1)
+     */
     // Driver program to test above functions
     public static void main(String[] args) {
         ListNode head = new ListNode(15);
@@ -80,18 +87,3 @@ public static void main(String[] args) {
         System.out.println("Random Node : " + randomNum);
     }
 }
-/**
- * OUTPUT :
- * First output :
- * Random Node : 25
- * Second output :
- * Random Node : 78
- * Time Complexity : O(n)
- * Auxiliary Space Complexity : O(1)
- * Time Complexity : O(n)
- * Auxiliary Space Complexity : O(1)
- */
-/**
- * Time Complexity : O(n)
- * Auxiliary Space Complexity : O(1)
- */
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
index bca3c77f2724..d5d3f31f4b66 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
@@ -5,7 +5,7 @@
 import java.util.StringJoiner;
 
 /**
- * https://en.wikipedia.org/wiki/Linked_list
+ * <a href="https://en.wikipedia.org/wiki/Linked_list">wikipedia</a>
  */
 public class SinglyLinkedList implements Iterable<Integer> {
 
@@ -95,7 +95,7 @@ public void swapNodes(int valueFirst, int valueSecond) {
             previousB = currentB;
             currentB = currentB.next;
         }
-        /** If either of 'a' or 'b' is not present, then return */
+        /* If either of 'a' or 'b' is not present, then return */
         if (currentA == null || currentB == null) {
             return;
         }
@@ -334,11 +334,6 @@ public void insertNth(int data, int position) {
         size++;
     }
 
-    /**
-     * Swaps nodes of two given values a and b.
-     *
-     */
-
     /**
      * Deletes a node at the head
      */
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java b/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
index f238b5e9fe8d..214e111b9f1a 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
@@ -18,8 +18,6 @@
  *
  * Ex.2. [30,20,40,10,25,35,50] represents level order traversal of a binary
  * search tree. Find ceil for 52 Answer: -1
- */
-/**
  *
  * Solution 1: Brute Force Solution: Do an inorder traversal and save result
  * into an array. Iterate over the array to get an element equal to or greater
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java b/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java
index 79c66cb90f01..d166653ff1b4 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java
@@ -1,12 +1,12 @@
 package com.thealgorithms.datastructures.trees;
 
+import java.util.Scanner;
+
 /**
  * Trie Data structure implementation without any libraries
  *
- * @author Dheeraj Kumar Barnwal (https://github.com/dheeraj92)
+ * @author <a href="https://github.com/dheeraj92">Dheeraj Kumar Barnwal</a>
  */
-import java.util.Scanner;
-
 public class TrieImp {
 
     public class TrieNode {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java b/src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java
index 8658bca3df52..d01066f611bd 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java
@@ -1,15 +1,14 @@
 package com.thealgorithms.dynamicprogramming;
 
+import java.util.Scanner;
 /**
  * This file contains an implementation of finding the nth CATALAN NUMBER using
- * dynamic programming Wikipedia: https://en.wikipedia.org/wiki/Catalan_number
+ * dynamic programming : <a href="https://en.wikipedia.org/wiki/Catalan_number">Wikipedia</a>
  *
  * Time Complexity: O(n^2) Space Complexity: O(n)
  *
- * @author AMRITESH ANAND (https://github.com/amritesh19)
+ * @author <a href="https://github.com/amritesh19">AMRITESH ANAND</a>
  */
-import java.util.Scanner;
-
 public final class CatalanNumber {
     private CatalanNumber() {
     }
@@ -31,7 +30,7 @@ static long findNthCatalan(int n) {
         catalanArray[0] = 1;
         catalanArray[1] = 1;
 
-        /**
+        /*
          * The Catalan numbers satisfy the recurrence relation C₀=1 and Cn = Σ
          * (Ci * Cn-1-i), i = 0 to n-1 , n > 0
          */
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java b/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java
index 8c70c9c3fada..e731524d4958 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java
@@ -1,20 +1,14 @@
+package com.thealgorithms.dynamicprogramming;
+
 /**
- * Author : Siddhant Swarup Mallick
- * Github : https://github.com/siddhant2002
- */
-/**
+ * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
+
  * In mathematics, the Golomb sequence is a non-decreasing integer sequence where n-th term is equal
  * to number of times n appears in the sequence.
- */
 
-/**
- * Wikipedia Link - https://en.wikipedia.org/wiki/Golomb_sequence
+ * <a href="https://en.wikipedia.org/wiki/Golomb_sequence">Wikipedia</a>
+ * Program description - To find the Golomb sequence upto n
  */
-
-/** Program description - To find the Golomb sequence upto n */
-
-package com.thealgorithms.dynamicprogramming;
-
 public final class CountFriendsPairing {
     private CountFriendsPairing() {
     }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java b/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
index 6db30514db68..55ce50d30ea4 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.dynamicprogramming;
 
+import java.util.Scanner;
 /**
  * A DynamicProgramming based solution for Edit Distance problem In Java
  * Description of Edit Distance with an Example:
@@ -22,8 +23,6 @@
  *
  * @author SUBHAM SANGHAI
  */
-import java.util.Scanner;
-
 public final class EditDistance {
     private EditDistance() {
     }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
index 9962cca217a0..905815d10a29 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
@@ -1,15 +1,20 @@
-/**
- * Author : Siddhant Swarup Mallick
- * Github : https://github.com/siddhant2002
- */
-
-/** Program description - To find the maximum subarray sum */
 package com.thealgorithms.dynamicprogramming;
 
+/**
+ * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
+ * Program description - To find the maximum subarray sum
+ */
 public final class KadaneAlgorithm {
     private KadaneAlgorithm() {
     }
 
+    /**
+     * OUTPUT :
+     * Input - {89,56,98,123,26,75,12,40,39,68,91}
+     * Output: it returns either true or false
+     * 1st approach Time Complexity : O(n)
+     * Auxiliary Space Complexity : O(1)
+     */
     public static boolean maxSum(int[] a, int predictedAnswer) {
         int sum = a[0];
         int runningSum = 0;
@@ -28,11 +33,4 @@ public static boolean maxSum(int[] a, int predictedAnswer) {
         // It returns true if sum and predicted answer matches
         // The predicted answer is the answer itself. So it always return true
     }
-    /**
-     * OUTPUT :
-     * Input - {89,56,98,123,26,75,12,40,39,68,91}
-     * Output: it returns either true or false
-     * 1st approach Time Complexity : O(n)
-     * Auxiliary Space Complexity : O(1)
-     */
 }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java b/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
index 5d31d40dacdc..d15ea1f78a78 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
@@ -1,13 +1,10 @@
-/**
- * Author : Siddhant Swarup Mallick
- * Github : https://github.com/siddhant2002
- */
-
-/** Program description - To find the New Man Shanks Prime. */
-/** Wikipedia Link - https://en.wikipedia.org/wiki/Newman%E2%80%93Shanks%E2%80%93Williams_prime */
-
 package com.thealgorithms.dynamicprogramming;
 
+/**
+ * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
+ * Program description - To find the New Man Shanks Prime.
+ * <a href="https://en.wikipedia.org/wiki/Newman%E2%80%93Shanks%E2%80%93Williams_prime">Wikipedia</a>
+ */
 public final class NewManShanksPrime {
     private NewManShanksPrime() {
     }
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java b/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java
index 43427457e307..c07563ad0020 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java
@@ -6,8 +6,6 @@
  * cover the entire text ?-> matches single characters *-> match the sequence of
  * characters
  *
- */
-/**
  * For calculation of Time and Space Complexity. Let N be length of src and M be
  * length of pat
  *
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java
index cbe3ccae4ac7..0c5bc2c5884d 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java
@@ -3,8 +3,8 @@
 /**
  * Find the number of subsets present in the given array with a sum equal to target.
  * Based on Solution discussed on
- * StackOverflow(https://stackoverflow.com/questions/22891076/count-number-of-subsets-with-sum-equal-to-k)
- * @author Samrat Podder(https://github.com/samratpodder)
+ * <a href="https://stackoverflow.com/questions/22891076/count-number-of-subsets-with-sum-equal-to-k">StackOverflow</a>
+ * @author <a href="https://github.com/samratpodder">Samrat Podder</a>
  */
 public final class SubsetCount {
     private SubsetCount() {
@@ -19,7 +19,7 @@ private SubsetCount() {
      *
      */
     public static int getCount(int[] arr, int target) {
-        /**
+        /*
          * Base Cases - If target becomes zero, we have reached the required sum for the subset
          * If we reach the end of the array arr then, either if target==arr[end], then we add one to
          * the final count Otherwise we add 0 to the final count
diff --git a/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java b/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
index 03c8a8989bb2..31f81da63f03 100644
--- a/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
+++ b/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java
@@ -1,15 +1,13 @@
 package com.thealgorithms.maths;
 
+import java.math.BigInteger;
 /**
- * Wikipedia link for Automorphic Number : https://en.wikipedia.org/wiki/Automorphic_number
+ * <a href="https://en.wikipedia.org/wiki/Automorphic_number">Automorphic Number</a>
  * A number is said to be an Automorphic, if it is present in the last digit(s)
  * of its square. Example- Let the number be 25, its square is 625. Since,
  * 25(The input number) is present in the last two digits of its square(625), it
  * is an Automorphic Number.
  */
-
-import java.math.BigInteger;
-
 public final class AutomorphicNumber {
     private AutomorphicNumber() {
     }
diff --git a/src/main/java/com/thealgorithms/maths/DigitalRoot.java b/src/main/java/com/thealgorithms/maths/DigitalRoot.java
index 84b33f34c393..e8f5305c7569 100644
--- a/src/main/java/com/thealgorithms/maths/DigitalRoot.java
+++ b/src/main/java/com/thealgorithms/maths/DigitalRoot.java
@@ -1,8 +1,7 @@
+package com.thealgorithms.maths;
+
 /**
- * Author : Suraj Kumar Modi
- * https://github.com/skmodi649
- */
-/**
+ * @author <a href="https://github.com/skmodi649">Suraj Kumar Modi</a>
  * You are given a number n. You need to find the digital root of n.
  * DigitalRoot of a number is the recursive sum of its digits until we get a single digit number.
  *
@@ -20,8 +19,6 @@
  * which is not a single digit number, hence
  * sum of digit of 45 is 9 which is a single
  * digit number.
- */
-/**
  * Algorithm :
  * Step 1 : Define a method digitalRoot(int n)
  * Step 2 : Define another method single(int n)
@@ -38,8 +35,6 @@
  * Step 5 : In main method simply take n as input and then call digitalRoot(int n) function and
  * print the result
  */
-package com.thealgorithms.maths;
-
 final class DigitalRoot {
     private DigitalRoot() {
     }
@@ -53,6 +48,11 @@ public static int digitalRoot(int n) {
         }
     }
 
+    /**
+     * Time Complexity: O((Number of Digits)^2) Auxiliary Space Complexity:
+     * O(Number of Digits) Constraints: 1 <= n <= 10^7
+     */
+
     // This function is used for finding the sum of the digits of number
     public static int single(int n) {
         if (n <= 9) { // if n becomes less than 10 than return n
@@ -63,7 +63,3 @@ public static int single(int n) {
     } // n / 10 is the number obtained after removing the digit one by one
     // The Sum of digits is stored in the Stack memory and then finally returned
 }
-/**
- * Time Complexity: O((Number of Digits)^2) Auxiliary Space Complexity:
- * O(Number of Digits) Constraints: 1 <= n <= 10^7
- */
diff --git a/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java b/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java
index a0dbfb1f70a4..01a52b913d30 100644
--- a/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java
+++ b/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java
@@ -1,18 +1,26 @@
-/**
- * Author : Siddhant Swarup Mallick
- * Github : https://github.com/siddhant2002
- */
-
-/** Program description - To find out the inverse square root of the given number*/
-
-/** Wikipedia Link - https://en.wikipedia.org/wiki/Fast_inverse_square_root */
-
 package com.thealgorithms.maths;
 
+/**
+ * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
+ * Program description - To find out the inverse square root of the given number
+ * <a href="https://en.wikipedia.org/wiki/Fast_inverse_square_root">Wikipedia</a>
+ */
 public final class FastInverseSqrt {
     private FastInverseSqrt() {
     }
-
+    /**
+     * Returns the inverse square root of the given number upto 6 - 8 decimal places.
+     * calculates the inverse square root of the given number and returns true if calculated answer
+     * matches with given answer else returns false
+     *
+     * OUTPUT :
+     * Input - number = 4522
+     * Output: it calculates the inverse squareroot of a number and returns true with it matches the
+     * given answer else returns false. 1st approach Time Complexity : O(1) Auxiliary Space Complexity :
+     * O(1) Input - number = 4522 Output: it calculates the inverse squareroot of a number and returns
+     * true with it matches the given answer else returns false. 2nd approach Time Complexity : O(1)
+     * Auxiliary Space Complexity : O(1)
+     */
     public static boolean inverseSqrt(float number) {
         float x = number;
         float xhalf = 0.5f * x;
@@ -24,11 +32,10 @@ public static boolean inverseSqrt(float number) {
     }
 
     /**
-     * Returns the inverse square root of the given number upto 6 - 8 decimal places.
+     * Returns the inverse square root of the given number upto 14 - 16 decimal places.
      * calculates the inverse square root of the given number and returns true if calculated answer
      * matches with given answer else returns false
      */
-
     public static boolean inverseSqrt(double number) {
         double x = number;
         double xhalf = 0.5d * x;
@@ -41,18 +48,4 @@ public static boolean inverseSqrt(double number) {
         x *= number;
         return x == 1 / Math.sqrt(number);
     }
-    /**
-     * Returns the inverse square root of the given number upto 14 - 16 decimal places.
-     * calculates the inverse square root of the given number and returns true if calculated answer
-     * matches with given answer else returns false
-     */
 }
-/**
- * OUTPUT :
- * Input - number = 4522
- * Output: it calculates the inverse squareroot of a number and returns true with it matches the
- * given answer else returns false. 1st approach Time Complexity : O(1) Auxiliary Space Complexity :
- * O(1) Input - number = 4522 Output: it calculates the inverse squareroot of a number and returns
- * true with it matches the given answer else returns false. 2nd approach Time Complexity : O(1)
- * Auxiliary Space Complexity : O(1)
- */
diff --git a/src/main/java/com/thealgorithms/maths/FrizzyNumber.java b/src/main/java/com/thealgorithms/maths/FrizzyNumber.java
index 3ae5e021df1b..ff2b00c26ce2 100644
--- a/src/main/java/com/thealgorithms/maths/FrizzyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/FrizzyNumber.java
@@ -1,12 +1,9 @@
-/**
- * Author : Siddhant Swarup Mallick
- * Github : https://github.com/siddhant2002
- */
-
-/** Program description - To find the FrizzyNumber*/
-
 package com.thealgorithms.maths;
 
+/**
+ * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
+ * Program description - To find the FrizzyNumber
+ */
 public final class FrizzyNumber {
     private FrizzyNumber() {
     }
diff --git a/src/main/java/com/thealgorithms/maths/JosephusProblem.java b/src/main/java/com/thealgorithms/maths/JosephusProblem.java
index 7d19623b3ed0..98d839011a7f 100644
--- a/src/main/java/com/thealgorithms/maths/JosephusProblem.java
+++ b/src/main/java/com/thealgorithms/maths/JosephusProblem.java
@@ -5,9 +5,7 @@
  * numbered from 1 to n in clockwise order. More formally, moving clockwise from the ith friend
  * brings you to the (i+1)th friend for 1 <= i < n, and moving clockwise from the nth friend brings
  * you to the 1st friend.
- */
 
-/**
    The rules of the game are as follows:
 
         1.Start at the 1st friend.
@@ -19,7 +17,6 @@
 
         @author Kunal
     */
-
 public final class JosephusProblem {
     private JosephusProblem() {
     }
diff --git a/src/main/java/com/thealgorithms/maths/PascalTriangle.java b/src/main/java/com/thealgorithms/maths/PascalTriangle.java
index 95f92fbe1b49..9a9d4450cb98 100644
--- a/src/main/java/com/thealgorithms/maths/PascalTriangle.java
+++ b/src/main/java/com/thealgorithms/maths/PascalTriangle.java
@@ -37,17 +37,17 @@ private PascalTriangle() {
      */
 
     public static int[][] pascal(int n) {
-        /**
+        /*
          * @param arr  An auxiliary array to store generated pascal triangle values
          * @return
          */
         int[][] arr = new int[n][n];
-        /**
+        /*
          * @param line Iterate through every line and print integer(s) in it
          * @param i Represents the column number of the element we are currently on
          */
         for (int line = 0; line < n; line++) {
-            /**
+            /*
              *  @Every line has number of integers equal to line number
              */
             for (int i = 0; i <= line; i++) {
diff --git a/src/main/java/com/thealgorithms/others/BankersAlgorithm.java b/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
index a22d7c737415..836526529374 100644
--- a/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.others;
 
+import java.util.Scanner;
+
 /**
  * This file contains an implementation of BANKER'S ALGORITM Wikipedia:
  * https://en.wikipedia.org/wiki/Banker%27s_algorithm
@@ -18,8 +20,6 @@
  *
  * @author AMRITESH ANAND (https://github.com/amritesh19)
  */
-import java.util.Scanner;
-
 public final class BankersAlgorithm {
     private BankersAlgorithm() {
     }
diff --git a/src/main/java/com/thealgorithms/others/Dijkstra.java b/src/main/java/com/thealgorithms/others/Dijkstra.java
index e2a778f8d6c3..a379100a2f3b 100644
--- a/src/main/java/com/thealgorithms/others/Dijkstra.java
+++ b/src/main/java/com/thealgorithms/others/Dijkstra.java
@@ -1,5 +1,9 @@
 package com.thealgorithms.others;
 
+import java.util.HashMap;
+import java.util.Map;
+import java.util.NavigableSet;
+import java.util.TreeSet;
 /**
  * Dijkstra's algorithm,is a graph search algorithm that solves the
  * single-source shortest path problem for a graph with nonnegative edge path
@@ -15,11 +19,6 @@
  * https://rosettacode.org/wiki/Dijkstra%27s_algorithm#Java Also most of the
  * comments are from RosettaCode.
  */
-import java.util.HashMap;
-import java.util.Map;
-import java.util.NavigableSet;
-import java.util.TreeSet;
-
 public final class Dijkstra {
     private Dijkstra() {
     }
diff --git a/src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java b/src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java
index 1f5f455f24e3..0924b8569942 100644
--- a/src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java
+++ b/src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java
@@ -1,11 +1,9 @@
 package com.thealgorithms.others;
 
+import java.util.ArrayList;
 /**
  * @author Alexandros Lemonaris
  */
-
-import java.util.ArrayList;
-
 public abstract class MemoryManagementAlgorithms {
 
     /**
diff --git a/src/main/java/com/thealgorithms/others/RabinKarp.java b/src/main/java/com/thealgorithms/others/RabinKarp.java
index f8ca33becad3..cecf24e09b4a 100644
--- a/src/main/java/com/thealgorithms/others/RabinKarp.java
+++ b/src/main/java/com/thealgorithms/others/RabinKarp.java
@@ -1,12 +1,13 @@
 package com.thealgorithms.others;
 
+import java.util.Scanner;
+
 /**
  * @author Prateek Kumar Oraon (https://github.com/prateekKrOraon)
+ *
+ An implementation of Rabin-Karp string matching algorithm
+ Program will simply end if there is no match
  */
-import java.util.Scanner;
-
-// An implementation of Rabin-Karp string matching algorithm
-// Program will simply end if there is no match
 public final class RabinKarp {
     private RabinKarp() {
     }
diff --git a/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java b/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
index 3930ca3e95ff..6ad0ef024342 100644
--- a/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
+++ b/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
@@ -1,11 +1,10 @@
 package com.thealgorithms.others;
 
+import java.util.Scanner;
 /**
  * Given a matrix of size n x n We have to rotate this matrix by 90 Degree Here
  * is the algorithm for this problem .
  */
-import java.util.Scanner;
-
 final class RotateMatrixBy90Degrees {
     private RotateMatrixBy90Degrees() {
     }
diff --git a/src/main/java/com/thealgorithms/sorts/LinkListSort.java b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
index c9000f7e3778..bf8910d94eae 100644
--- a/src/main/java/com/thealgorithms/sorts/LinkListSort.java
+++ b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
@@ -1,14 +1,10 @@
-/**
- * Author : Siddhant Swarup Mallick
- * Github : https://github.com/siddhant2002
- */
-
-/** Program description - To sort the LinkList as per sorting technique */
-
 package com.thealgorithms.sorts;
 
 import java.util.Arrays;
-
+/**
+ * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
+ * Program description - To sort the LinkList as per sorting technique
+ */
 public class LinkListSort {
 
     public static boolean isSorted(int[] p, int option) {
@@ -116,17 +112,6 @@ public static boolean isSorted(int[] p, int option) {
         // Switch case is used to call the classes as per the user requirement
         return false;
     }
-
-    boolean compare(int[] a, int[] b) {
-        for (int i = 0; i < a.length; i++) {
-            if (a[i] != b[i]) {
-                return false;
-            }
-        }
-        return true;
-        // Both the arrays are checked for equalness. If both are equal then true is
-        // returned else false is returned
-    }
     /**
      * OUTPUT :
      * Input - {89,56,98,123,26,75,12,40,39,68,91} is same for all the 3 classes
@@ -138,6 +123,16 @@ boolean compare(int[] a, int[] b) {
      * 3rd approach Time Complexity : O(n logn)
      * Auxiliary Space Complexity : O(n)
      */
+    boolean compare(int[] a, int[] b) {
+        for (int i = 0; i < a.length; i++) {
+            if (a[i] != b[i]) {
+                return false;
+            }
+        }
+        return true;
+        // Both the arrays are checked for equalness. If both are equal then true is
+        // returned else false is returned
+    }
 }
 
 class Node {
diff --git a/src/main/java/com/thealgorithms/strings/Anagrams.java b/src/main/java/com/thealgorithms/strings/Anagrams.java
index 106be5e1a596..f5e8fa84cd41 100644
--- a/src/main/java/com/thealgorithms/strings/Anagrams.java
+++ b/src/main/java/com/thealgorithms/strings/Anagrams.java
@@ -12,8 +12,24 @@
  */
 public class Anagrams {
 
-    // 4 approaches are provided for anagram checking. approach 2 and approach 3 are similar but
-    // differ in running time.
+    /**
+     * 4 approaches are provided for anagram checking. approach 2 and approach 3 are similar but
+     * differ in running time.
+     * OUTPUT :
+     * first string ="deal" second string ="lead"
+     * Output: Anagram
+     * Input and output is constant for all four approaches
+     * 1st approach Time Complexity : O(n logn)
+     * Auxiliary Space Complexity : O(1)
+     * 2nd approach Time Complexity : O(n)
+     * Auxiliary Space Complexity : O(1)
+     * 3rd approach Time Complexity : O(n)
+     * Auxiliary Space Complexity : O(1)
+     * 4th approach Time Complexity : O(n)
+     * Auxiliary Space Complexity : O(n)
+     * 5th approach Time Complexity: O(n)
+     * Auxiliary Space Complexity: O(1)
+     */
     public static void main(String[] args) {
         String first = "deal";
         String second = "lead";
@@ -23,22 +39,6 @@ public static void main(String[] args) {
         System.out.println(nm.approach1(first, second)); /* To activate methods for different approaches*/
         System.out.println(nm.approach3(first, second)); /* To activate methods for different approaches*/
         System.out.println(nm.approach4(first, second)); /* To activate methods for different approaches*/
-        /**
-         * OUTPUT :
-         * first string ="deal" second string ="lead"
-         * Output: Anagram
-         * Input and output is constant for all four approaches
-         * 1st approach Time Complexity : O(n logn)
-         * Auxiliary Space Complexity : O(1)
-         * 2nd approach Time Complexity : O(n)
-         * Auxiliary Space Complexity : O(1)
-         * 3rd approach Time Complexity : O(n)
-         * Auxiliary Space Complexity : O(1)
-         * 4th approach Time Complexity : O(n)
-         * Auxiliary Space Complexity : O(n)
-         * 5th approach Time Complexity: O(n)
-         * Auxiliary Space Complexity: O(1)
-         */
     }
 
     boolean approach1(String s, String t) {
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java
index 13761ac23e44..f54070d39cdd 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java
@@ -1,15 +1,13 @@
 package com.thealgorithms.bitmanipulation;
 
-/**
- * test Cases of Numbers Different Signs
- * @author Bama Charan Chhandogi
- */
-
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
-
+/**
+ * test Cases of Numbers Different Signs
+ * @author Bama Charan Chhandogi
+ */
 class NumbersDifferentSignsTest {
 
     @Test
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
index 579e236699b3..8cd0b0a6838f 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
@@ -30,7 +30,7 @@ public void testBoruvkaMSTV9E14() {
         edges.add(new BoruvkaAlgorithm.Edge(7, 8, 11));
 
         final var graph = new Graph(9, edges);
-        /**
+        /*
          * Adjacency matrix
          *    0   1   2   3   4   5   6   7   8
          * 0  0  10  12   0   0   0   0   0   0
@@ -56,7 +56,7 @@ void testBoruvkaMSTV2E1() {
 
         final var graph = new Graph(2, edges);
 
-        /**
+        /*
          * Adjacency matrix
          *    0  1
          * 0  0  10
@@ -79,7 +79,7 @@ void testCompleteGraphK4() {
 
         final var graph = new Graph(4, edges);
 
-        /**
+        /*
          * Adjacency matrix
          *    0  1  2  3
          * 0  0  7  2  5
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
index c4113b787de9..91e2ba5d43ce 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
@@ -1,16 +1,14 @@
 package com.thealgorithms.datastructures.lists;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
 /**
  * Test cases for QuickSortLinkedList
  * Author: Prabhat-Kumar-42
  * GitHub: https://github.com/Prabhat-Kumar-42
  */
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNull;
-
-import org.junit.jupiter.api.Test;
-
 public class QuickSortLinkedListTest {
 
     @Test
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java b/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
index c03f5b14c641..e7e3cca4083f 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
@@ -1,15 +1,13 @@
 package com.thealgorithms.datastructures.lists;
 
-/**
- * Test cases for Reverse K Group LinkedList
- * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
- */
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
 
 import org.junit.jupiter.api.Test;
-
+/**
+ * Test cases for Reverse K Group LinkedList
+ * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
+ */
 public class ReverseKGroupTest {
 
     @Test
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java b/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
index d3c020f8881b..8b2ae424364e 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
@@ -1,15 +1,14 @@
 package com.thealgorithms.datastructures.lists;
 
-/**
- * Test cases for RotateSinglyLinkedLists
- * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
- */
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
 
 import org.junit.jupiter.api.Test;
 
+/**
+ * Test cases for RotateSinglyLinkedLists
+ * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
+ */
 public class RotateSinglyLinkedListsTest {
 
     @Test
diff --git a/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
index 61e2a2ac2690..1c8a25dfda49 100644
--- a/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
@@ -1,10 +1,5 @@
 package com.thealgorithms.scheduling;
 
-/**
- * Test Cases of Preemptive Priority Scheduling Algorithm
- * @author [Bama Charan Chhandogi](https://www.github.com/BamaCharanChhandogi)
- */
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
@@ -12,6 +7,10 @@
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
+/**
+ * Test Cases of Preemptive Priority Scheduling Algorithm
+ * @author [Bama Charan Chhandogi](https://www.github.com/BamaCharanChhandogi)
+ */
 class PreemptivePrioritySchedulingTest {
 
     @Test
diff --git a/src/test/java/com/thealgorithms/strings/WordLadderTest.java b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
index 4f1d07ebdc4a..c59f2d8b31be 100644
--- a/src/test/java/com/thealgorithms/strings/WordLadderTest.java
+++ b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
@@ -8,30 +8,32 @@
 
 public class WordLadderTest {
 
+    /**
+     * Test 1:
+     * Input: beginWord = "hit", endWord = "cog", wordList =
+     * ["hot","dot","dog","lot","log","cog"]
+     * Output: 5
+     * Explanation: One shortest transformation sequence is
+     * "hit" -> "hot" -> "dot" -> "dog" -> cog"
+     * which is 5 words long.
+     */
     @Test
     public void testWordLadder() {
 
-        /**
-         * Test 1:
-         * Input: beginWord = "hit", endWord = "cog", wordList =
-         * ["hot","dot","dog","lot","log","cog"]
-         * Output: 5
-         * Explanation: One shortest transformation sequence is
-         * "hit" -> "hot" -> "dot" -> "dog" -> cog"
-         * which is 5 words long.
-         */
-
         List<String> wordList1 = Arrays.asList("hot", "dot", "dog", "lot", "log", "cog");
         assertEquals(WordLadder.ladderLength("hit", "cog", wordList1), 5);
+    }
 
-        /**
-         * Test 2:
-         * Input: beginWord = "hit", endWord = "cog", wordList =
-         * ["hot","dot","dog","lot","log"]
-         * Output: 0
-         * Explanation: The endWord "cog" is not in wordList,
-         * therefore there is no valid transformation sequence.
-         */
+    /**
+     * Test 2:
+     * Input: beginWord = "hit", endWord = "cog", wordList =
+     * ["hot","dot","dog","lot","log"]
+     * Output: 0
+     * Explanation: The endWord "cog" is not in wordList,
+     * therefore there is no valid transformation sequence.
+     */
+    @Test
+    public void testWordLadder2() {
 
         List<String> wordList2 = Arrays.asList("hot", "dot", "dog", "lot", "log");
         assertEquals(WordLadder.ladderLength("hit", "cog", wordList2), 0);

From bf4fc3f9c296c4510765f5bd8e885bed4c2f24dc Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 19 Jun 2024 07:18:53 +0200
Subject: [PATCH 0207/1338] Chore(deps): bump
 org.apache.commons:commons-collections4 from 4.5.0-M1 to 4.5.0-M2 (#5240)

Chore(deps): bump org.apache.commons:commons-collections4

Bumps org.apache.commons:commons-collections4 from 4.5.0-M1 to 4.5.0-M2.

---
updated-dependencies:
- dependency-name: org.apache.commons:commons-collections4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index a3a2b39e24de..6f28c62b5099 100644
--- a/pom.xml
+++ b/pom.xml
@@ -55,7 +55,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-collections4</artifactId>
-            <version>4.5.0-M1</version>
+            <version>4.5.0-M2</version>
         </dependency>
     </dependencies>
 

From a9db8428b29dc472c488191843af2110e115330c Mon Sep 17 00:00:00 2001
From: Alex K <alexanderklmn@gmail.com>
Date: Wed, 19 Jun 2024 19:57:54 +0300
Subject: [PATCH 0208/1338] Refactoring BinaryInsertionSort according to common
 SortAlgorithm approach (#5239)

* Refactoring BinaryInsertionSort according to common SortAlgorithm approach

* Formatting has been fixed

* Refactoring tests for BinaryInsertionSort according to SortingAlgorithmTest

* Removing redundant tests and improving variable readability

---------

Co-authored-by: alx <alx@alx.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../sorts/BinaryInsertionSort.java            | 21 +++++++++++----
 .../sorts/BinaryInsertionSortTest.java        | 27 ++++---------------
 2 files changed, 21 insertions(+), 27 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java b/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java
index 13076c617c76..b6f5d92e7928 100644
--- a/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java
@@ -1,17 +1,28 @@
 package com.thealgorithms.sorts;
 
-public class BinaryInsertionSort {
+/**
+ * BinaryInsertionSort class implements the SortAlgorithm interface using the binary insertion sort technique.
+ * Binary Insertion Sort improves upon the simple insertion sort by using binary search to find the appropriate
+ * location to insert the new element, reducing the number of comparisons in the insertion step.
+ */
+public class BinaryInsertionSort implements SortAlgorithm {
 
-    // Binary Insertion Sort method
-    public int[] binaryInsertSort(int[] array) {
+    /**
+     * Sorts the given array using the Binary Insertion Sort algorithm.
+     *
+     * @param <T> the type of elements in the array, which must implement the Comparable interface
+     * @param array the array to be sorted
+     * @return the sorted array
+     */
+    public <T extends Comparable<T>> T[] sort(T[] array) {
         for (int i = 1; i < array.length; i++) {
-            int temp = array[i];
+            final T temp = array[i];
             int low = 0;
             int high = i - 1;
 
             while (low <= high) {
                 final int mid = (low + high) >>> 1;
-                if (temp < array[mid]) {
+                if (temp.compareTo(array[mid]) < 0) {
                     high = mid - 1;
                 } else {
                     low = mid + 1;
diff --git a/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java b/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
index bdd0702942a2..82cb3ba60987 100644
--- a/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java
@@ -1,27 +1,10 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+class BinaryInsertionSortTest extends SortingAlgorithmTest {
+    private final BinaryInsertionSort binaryInsertionSort = new BinaryInsertionSort();
 
-import org.junit.jupiter.api.Test;
-
-class BinaryInsertionSortTest {
-
-    BinaryInsertionSort bis = new BinaryInsertionSort();
-
-    @Test
-    // valid test case
-    public void binaryInsertionSortTestNonDuplicate() {
-        int[] array = {1, 0, 2, 5, 3, 4, 9, 8, 10, 6, 7};
-        int[] expResult = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
-        int[] actResult = bis.binaryInsertSort(array);
-        assertArrayEquals(expResult, actResult);
-    }
-
-    @Test
-    public void binaryInsertionSortTestDuplicate() {
-        int[] array = {1, 1, 1, 5, 9, 8, 7, 2, 6};
-        int[] expResult = {1, 1, 1, 2, 5, 6, 7, 8, 9};
-        int[] actResult = bis.binaryInsertSort(array);
-        assertArrayEquals(expResult, actResult);
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return binaryInsertionSort;
     }
 }

From 91101ec424d5ee78c5e132e29d6fb7492601c2ef Mon Sep 17 00:00:00 2001
From: Alex K <alexanderklmn@gmail.com>
Date: Thu, 20 Jun 2024 09:26:09 +0300
Subject: [PATCH 0209/1338] Refactoring and code improving for OddEvenSort
 (#5242)

* Refactoring and code improving for OddEvenSort, changing it according to SortAlgorithm approach, also applying SortUtils

* Fix checkstyle

* Remove redundant main, remove redundant tests.

---------

Co-authored-by: alx <alx@alx.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/sorts/OddEvenSort.java  | 66 ++++++-------------
 .../thealgorithms/sorts/OddEvenSortTest.java  | 31 ++-------
 2 files changed, 24 insertions(+), 73 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/OddEvenSort.java b/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
index fb6e4d2649cb..8db85f39e9ac 100644
--- a/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
+++ b/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
@@ -1,69 +1,41 @@
 package com.thealgorithms.sorts;
 
-import java.util.Random;
-
-// https://en.wikipedia.org/wiki/Odd%E2%80%93even_sort
-public final class OddEvenSort {
-    private OddEvenSort() {
-    }
-
-    public static void main(String[] args) {
-        int[] arr = new int[100];
-
-        Random random = new Random();
-
-        // Print out unsorted elements
-        for (int i = 0; i < arr.length; ++i) {
-            arr[i] = random.nextInt(100) - 50;
-            System.out.println(arr[i]);
-        }
-        System.out.println("--------------");
-
-        oddEvenSort(arr);
-
-        // Print Sorted elements
-        for (int i = 0; i < arr.length - 1; ++i) {
-            System.out.println(arr[i]);
-            assert arr[i] <= arr[i + 1];
-        }
-    }
+/**
+ * OddEvenSort class implements the SortAlgorithm interface using the odd-even sort technique.
+ * Odd-even sort is a comparison sort related to bubble sort.
+ * It operates by comparing all (odd, even)-indexed pairs of adjacent elements in the list and, if a pair is in the wrong order, swapping them.
+ * The next step repeats this process for (even, odd)-indexed pairs. This process continues until the list is sorted.
+ *
+ */
+public final class OddEvenSort implements SortAlgorithm {
 
     /**
-     * Odd Even Sort algorithms implements
+     * Sorts the given array using the Odd-Even Sort algorithm.
      *
-     * @param arr the array contains elements
+     * @param <T> the type of elements in the array, which must implement the Comparable interface
+     * @param arr the array to be sorted
+     * @return the sorted array
      */
-    public static void oddEvenSort(int[] arr) {
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] arr) {
         boolean sorted = false;
         while (!sorted) {
             sorted = true;
 
             for (int i = 1; i < arr.length - 1; i += 2) {
-                if (arr[i] > arr[i + 1]) {
-                    swap(arr, i, i + 1);
+                if (arr[i].compareTo(arr[i + 1]) > 0) {
+                    SortUtils.swap(arr, i, i + 1);
                     sorted = false;
                 }
             }
 
             for (int i = 0; i < arr.length - 1; i += 2) {
-                if (arr[i] > arr[i + 1]) {
-                    swap(arr, i, i + 1);
+                if (arr[i].compareTo(arr[i + 1]) > 0) {
+                    SortUtils.swap(arr, i, i + 1);
                     sorted = false;
                 }
             }
         }
-    }
-
-    /**
-     * Helper function to swap two array values.
-     *
-     * @param arr the array contains elements
-     * @param i the first index to be swapped
-     * @param j the second index to be swapped
-     */
-    private static void swap(int[] arr, int i, int j) {
-        int temp = arr[i];
-        arr[i] = arr[j];
-        arr[j] = temp;
+        return arr;
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/OddEvenSortTest.java b/src/test/java/com/thealgorithms/sorts/OddEvenSortTest.java
index a7d0a58e229d..09ef8014cec1 100644
--- a/src/test/java/com/thealgorithms/sorts/OddEvenSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/OddEvenSortTest.java
@@ -1,36 +1,15 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-
-import org.junit.jupiter.api.Test;
-
 /**
  * @author Tabbygray (https://github.com/Tabbygray)
  * @see OddEvenSort
  */
 
-public class OddEvenSortTest {
-    @Test
-    public void oddEvenSortEmptyArray() {
-        int[] inputArray = {};
-        OddEvenSort.oddEvenSort(inputArray);
-        int[] expectedOutput = {};
-        assertArrayEquals(inputArray, expectedOutput);
-    }
-
-    @Test
-    public void oddEvenSortNaturalNumberArray() {
-        int[] inputArray = {18, 91, 86, 60, 21, 44, 37, 78, 98, 67};
-        OddEvenSort.oddEvenSort(inputArray);
-        int[] expectedOutput = {18, 21, 37, 44, 60, 67, 78, 86, 91, 98};
-        assertArrayEquals(inputArray, expectedOutput);
-    }
+public class OddEvenSortTest extends SortingAlgorithmTest {
+    private final OddEvenSort oddEvenSort = new OddEvenSort();
 
-    @Test
-    public void oddEvenSortIntegerArray() {
-        int[] inputArray = {57, 69, -45, 12, -85, 3, -76, 36, 67, -14};
-        OddEvenSort.oddEvenSort(inputArray);
-        int[] expectedOutput = {-85, -76, -45, -14, 3, 12, 36, 57, 67, 69};
-        assertArrayEquals(inputArray, expectedOutput);
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return oddEvenSort;
     }
 }

From 15d2e706739451e0ca000bd63df82411d4d25053 Mon Sep 17 00:00:00 2001
From: Alex K <alexanderklmn@gmail.com>
Date: Thu, 20 Jun 2024 18:47:43 +0300
Subject: [PATCH 0210/1338] Refactoring and code improving for StrandSort
 (#5243)

* Refactoring and code improving for StrandSort

* Fix java checkstyle

* Fix "Each variable declaration must be in its own statement"

* Fix "uses integer based for loops to iterate over a List"

---------

Co-authored-by: alx <alx@alx.com>
---
 .../com/thealgorithms/sorts/StrandSort.java   | 83 +++++++++++++------
 .../thealgorithms/sorts/StrandSortTest.java   | 34 +-------
 2 files changed, 62 insertions(+), 55 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/StrandSort.java b/src/main/java/com/thealgorithms/sorts/StrandSort.java
index 51600812bbb1..58cd35628506 100644
--- a/src/main/java/com/thealgorithms/sorts/StrandSort.java
+++ b/src/main/java/com/thealgorithms/sorts/StrandSort.java
@@ -1,46 +1,79 @@
 package com.thealgorithms.sorts;
 
-import java.util.Iterator;
-import java.util.LinkedList;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 
-public final class StrandSort {
-    private StrandSort() {
+/**
+ * StrandSort class implementing the SortAlgorithm interface using arrays.
+ */
+public final class StrandSort implements SortAlgorithm {
+
+    /**
+     * Sorts the given array using the Strand Sort algorithm.
+     *
+     * @param <T> The type of elements to be sorted, must be Comparable.
+     * @param unsorted The array to be sorted.
+     * @return The sorted array.
+     */
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] unsorted) {
+        List<T> unsortedList = new ArrayList<>(Arrays.asList(unsorted));
+        List<T> sortedList = strandSort(unsortedList);
+        return sortedList.toArray(unsorted);
     }
 
-    // note: the input list is destroyed
-    public static <E extends Comparable<? super E>> LinkedList<E> strandSort(LinkedList<E> list) {
+    /**
+     * Strand Sort algorithm that sorts a list.
+     *
+     * @param <T> The type of elements to be sorted, must be Comparable.
+     * @param list The list to be sorted.
+     * @return The sorted list.
+     */
+    private static <T extends Comparable<? super T>> List<T> strandSort(List<T> list) {
         if (list.size() <= 1) {
             return list;
         }
 
-        LinkedList<E> result = new LinkedList<E>();
-        while (list.size() > 0) {
-            LinkedList<E> sorted = new LinkedList<E>();
-            sorted.add(list.removeFirst()); // same as remove() or remove(0)
-            for (Iterator<E> it = list.iterator(); it.hasNext();) {
-                E elem = it.next();
-                if (sorted.peekLast().compareTo(elem) <= 0) {
-                    sorted.addLast(elem); // same as add(elem) or add(0, elem)
-                    it.remove();
+        List<T> result = new ArrayList<>();
+        while (!list.isEmpty()) {
+            final List<T> sorted = new ArrayList<>();
+            sorted.add(list.remove(0));
+            for (int i = 0; i < list.size();) {
+                if (sorted.get(sorted.size() - 1).compareTo(list.get(i)) <= 0) {
+                    sorted.add(list.remove(i));
+                } else {
+                    i++;
                 }
             }
-            result = merge(sorted, result);
+            result = merge(result, sorted);
         }
         return result;
     }
 
-    private static <E extends Comparable<? super E>> LinkedList<E> merge(LinkedList<E> left, LinkedList<E> right) {
-        LinkedList<E> result = new LinkedList<E>();
-        while (!left.isEmpty() && !right.isEmpty()) {
-            // change the direction of this comparison to change the direction of the sort
-            if (left.peek().compareTo(right.peek()) <= 0) {
-                result.add(left.remove());
+    /**
+     * Merges two sorted lists into one sorted list.
+     *
+     * @param <T> The type of elements to be sorted, must be Comparable.
+     * @param left The first sorted list.
+     * @param right The second sorted list.
+     * @return The merged sorted list.
+     */
+    private static <T extends Comparable<? super T>> List<T> merge(List<T> left, List<T> right) {
+        List<T> result = new ArrayList<>();
+        int i = 0;
+        int j = 0;
+        while (i < left.size() && j < right.size()) {
+            if (left.get(i).compareTo(right.get(j)) <= 0) {
+                result.add(left.get(i));
+                i++;
             } else {
-                result.add(right.remove());
+                result.add(right.get(j));
+                j++;
             }
         }
-        result.addAll(left);
-        result.addAll(right);
+        result.addAll(left.subList(i, left.size()));
+        result.addAll(right.subList(j, right.size()));
         return result;
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/StrandSortTest.java b/src/test/java/com/thealgorithms/sorts/StrandSortTest.java
index 91e85c81e5ec..a7250acf9bec 100644
--- a/src/test/java/com/thealgorithms/sorts/StrandSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/StrandSortTest.java
@@ -1,34 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-
-import java.util.Arrays;
-import java.util.LinkedList;
-import org.junit.jupiter.api.Test;
-
-class StrandSortTest {
-
-    @Test
-    // valid test case
-    public void strandSortNonDuplicateTest() {
-        int[] expectedArray = {1, 2, 3, 4, 5};
-        LinkedList<Integer> actualList = StrandSort.strandSort(new LinkedList<Integer>(Arrays.asList(3, 1, 2, 4, 5)));
-        int[] actualArray = new int[actualList.size()];
-        for (int i = 0; i < actualList.size(); i++) {
-            actualArray[i] = actualList.get(i);
-        }
-        assertArrayEquals(expectedArray, actualArray);
-    }
-
-    @Test
-    // valid test case
-    public void strandSortDuplicateTest() {
-        int[] expectedArray = {2, 2, 2, 5, 7};
-        LinkedList<Integer> actualList = StrandSort.strandSort(new LinkedList<Integer>(Arrays.asList(7, 2, 2, 2, 5)));
-        int[] actualArray = new int[actualList.size()];
-        for (int i = 0; i < actualList.size(); i++) {
-            actualArray[i] = actualList.get(i);
-        }
-        assertArrayEquals(expectedArray, actualArray);
+class StrandSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new StrandSort();
     }
 }

From 8ef69bc85404a714c186f8aead26cd3d92595610 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 21 Jun 2024 22:37:58 +0300
Subject: [PATCH 0211/1338] Improving BitonicSort (#5244)

* Improving BitonicSort

* Moving max method to SortingUtils

* Adding Javadoc to merge method

* Fix for test and code improvements

* Improving code readability

* Renaming method parameters

---------

Co-authored-by: alx <alx@alx.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/sorts/BitonicSort.java  | 149 +++++++++++-------
 .../thealgorithms/sorts/BitonicSortTest.java  |   8 +
 2 files changed, 99 insertions(+), 58 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/sorts/BitonicSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/BitonicSort.java b/src/main/java/com/thealgorithms/sorts/BitonicSort.java
index b4b26299562f..90d204818729 100644
--- a/src/main/java/com/thealgorithms/sorts/BitonicSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BitonicSort.java
@@ -1,79 +1,112 @@
 package com.thealgorithms.sorts;
 
-/* Java program for Bitonic Sort. Note that this program
-works only when size of input is a power of 2. */
-public class BitonicSort {
-
-    /* The parameter dir indicates the sorting direction,
-  ASCENDING or DESCENDING; if (a[i] > a[j]) agrees
-  with the direction, then a[i] and a[j] are
-  interchanged. */
-    void compAndSwap(int[] a, int i, int j, int dir) {
-        if ((a[i] > a[j] && dir == 1) || (a[i] < a[j] && dir == 0)) {
-            // Swapping elements
-            int temp = a[i];
-            a[i] = a[j];
-            a[j] = temp;
-        }
+import java.util.Arrays;
+import java.util.function.BiPredicate;
+
+/**
+ * BitonicSort class implements the SortAlgorithm interface using the bitonic sort technique.
+ */
+public class BitonicSort implements SortAlgorithm {
+    private enum Direction {
+        DESCENDING,
+        ASCENDING,
     }
 
-    /* It recursively sorts a bitonic sequence in ascending
-  order, if dir = 1, and in descending order otherwise
-  (means dir=0). The sequence to be sorted starts at
-  index position low, the parameter cnt is the number
-  of elements to be sorted.*/
-    void bitonicMerge(int[] a, int low, int cnt, int dir) {
-        if (cnt > 1) {
-            int k = cnt / 2;
-            for (int i = low; i < low + k; i++) {
-                compAndSwap(a, i, i + k, dir);
-            }
-            bitonicMerge(a, low, k, dir);
-            bitonicMerge(a, low + k, k, dir);
+    /**
+     * Sorts the given array using the Bitonic Sort algorithm.
+     *
+     * @param <T> the type of elements in the array, which must implement the Comparable interface
+     * @param array the array to be sorted
+     * @return the sorted array
+     */
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array.length == 0) {
+            return array;
         }
+
+        final int paddedSize = nextPowerOfTwo(array.length);
+        T[] paddedArray = Arrays.copyOf(array, paddedSize);
+
+        // Fill the padded part with a maximum value
+        final T maxValue = max(array);
+        Arrays.fill(paddedArray, array.length, paddedSize, maxValue);
+
+        bitonicSort(paddedArray, 0, paddedSize, Direction.ASCENDING);
+        return Arrays.copyOf(paddedArray, array.length);
     }
 
-    /* This funcion first produces a bitonic sequence by
-  recursively sorting its two halves in opposite sorting
-  orders, and then calls bitonicMerge to make them in
-  the same order */
-    void bitonicSort(int[] a, int low, int cnt, int dir) {
+    private <T extends Comparable<T>> void bitonicSort(final T[] array, final int low, final int cnt, final Direction direction) {
         if (cnt > 1) {
-            int k = cnt / 2;
+            final int k = cnt / 2;
 
-            // sort in ascending order since dir here is 1
-            bitonicSort(a, low, k, 1);
+            // Sort first half in ascending order
+            bitonicSort(array, low, k, Direction.ASCENDING);
 
-            // sort in descending order since dir here is 0
-            bitonicSort(a, low + k, k, 0);
+            // Sort second half in descending order
+            bitonicSort(array, low + k, cnt - k, Direction.DESCENDING);
 
-            // Will merge whole sequence in ascending order
-            // since dir=1.
-            bitonicMerge(a, low, cnt, dir);
+            // Merge the whole sequence in ascending order
+            bitonicMerge(array, low, cnt, direction);
         }
     }
 
-    /*Caller of bitonicSort for sorting the entire array
-  of length N in ASCENDING order */
-    void sort(int[] a, int n, int up) {
-        bitonicSort(a, 0, n, up);
+    /**
+     * Merges the bitonic sequence in the specified direction.
+     *
+     * @param <T> the type of elements in the array, which must be Comparable
+     * @param array the array containing the bitonic sequence to be merged
+     * @param low the starting index of the sequence to be merged
+     * @param cnt the number of elements in the sequence to be merged
+     * @param direction the direction of sorting
+     */
+    private <T extends Comparable<T>> void bitonicMerge(T[] array, int low, int cnt, Direction direction) {
+        if (cnt > 1) {
+            final int k = cnt / 2;
+
+            final BiPredicate<T, T> areSorted = (direction == Direction.ASCENDING) ? (a, b) -> a.compareTo(b) < 0 : (a, b) -> a.compareTo(b) > 0;
+            for (int i = low; i < low + k; i++) {
+                if (!areSorted.test(array[i], array[i + k])) {
+                    SortUtils.swap(array, i, i + k);
+                }
+            }
+
+            bitonicMerge(array, low, k, direction);
+            bitonicMerge(array, low + k, cnt - k, direction);
+        }
     }
 
-    /* A utility function to print array of size n */
-    static void printArray(int[] arr) {
-        int n = arr.length;
-        for (int i = 0; i < n; ++i) {
-            System.out.print(arr[i] + " ");
+    /**
+     * Finds the next power of two greater than or equal to the given number.
+     *
+     * @param n the number
+     * @return the next power of two
+     */
+    private static int nextPowerOfTwo(int n) {
+        int count = 0;
+
+        // First n in the below condition is for the case where n is 0
+        if ((n & (n - 1)) == 0) {
+            return n;
+        }
+
+        while (n != 0) {
+            n >>= 1;
+            count += 1;
         }
-        System.out.println();
+
+        return 1 << count;
     }
 
-    public static void main(String[] args) {
-        int[] a = {3, 7, 4, 8, 6, 2, 1, 5};
-        int up = 1;
-        BitonicSort ob = new BitonicSort();
-        ob.sort(a, a.length, up);
-        System.out.println("\nSorted array");
-        printArray(a);
+    /**
+     * Finds the maximum element in the given array.
+     *
+     * @param <T> the type of elements in the array, which must implement the Comparable interface
+     * @param array the array to be searched
+     * @return the maximum element in the array
+     * @throws IllegalArgumentException if the array is null or empty
+     */
+    private static <T extends Comparable<T>> T max(final T[] array) {
+        return Arrays.stream(array).max(Comparable::compareTo).orElseThrow();
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java b/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java
new file mode 100644
index 000000000000..60c4bbe9d342
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.sorts;
+
+public class BitonicSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new BitonicSort();
+    }
+}

From e8f1990c8cf815bba8b3329a549759f060c01496 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 22 Jun 2024 11:18:39 +0300
Subject: [PATCH 0212/1338] Replace the various swap method variants with
 SortUtils.swap (#5245)

Fix different variants of swap methods to SortUtils.swap

Co-authored-by: AlexKlm <alx@alx.com>
---
 .../sorts/DualPivotQuickSort.java              | 18 ++++++------------
 .../com/thealgorithms/sorts/ExchangeSort.java  |  8 +-------
 .../thealgorithms/sorts/IntrospectiveSort.java | 16 +++++-----------
 .../com/thealgorithms/sorts/SelectionSort.java |  4 +---
 .../com/thealgorithms/sorts/SimpleSort.java    |  4 +---
 .../java/com/thealgorithms/sorts/SlowSort.java |  4 +---
 .../java/com/thealgorithms/sorts/SwapSort.java |  4 +---
 7 files changed, 16 insertions(+), 42 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java b/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java
index 5a6ba256521f..b02168f627c3 100644
--- a/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java
@@ -45,7 +45,7 @@ private static <T extends Comparable<T>> void dualPivotQuicksort(T[] array, int
      */
     private static <T extends Comparable<T>> int[] partition(T[] array, int left, int right) {
         if (array[left].compareTo(array[right]) > 0) {
-            swap(array, left, right);
+            SortUtils.swap(array, left, right);
         }
 
         T pivot1 = array[left];
@@ -58,7 +58,7 @@ private static <T extends Comparable<T>> int[] partition(T[] array, int left, in
         while (less <= great) {
             // If element is less than pivot1
             if (array[less].compareTo(pivot1) < 0) {
-                swap(array, less, left++);
+                SortUtils.swap(array, less, left++);
             }
 
             // If element is greater or equal to pivot2
@@ -67,10 +67,10 @@ else if (array[less].compareTo(pivot2) >= 0) {
                     great--;
                 }
 
-                swap(array, less, great--);
+                SortUtils.swap(array, less, great--);
 
                 if (array[less].compareTo(pivot1) < 0) {
-                    swap(array, less, left++);
+                    SortUtils.swap(array, less, left++);
                 }
             }
 
@@ -79,19 +79,13 @@ else if (array[less].compareTo(pivot2) >= 0) {
         j--;
         great++;
         // Bring the pivots to their appropriate positions
-        swap(array, left, j);
-        swap(array, right, great);
+        SortUtils.swap(array, left, j);
+        SortUtils.swap(array, right, great);
 
         // return the pivots' indices
         return new int[] {less, great};
     }
 
-    private static <T extends Comparable<T>> void swap(T[] array, int left, int right) {
-        T temp = array[left];
-        array[left] = array[right];
-        array[right] = temp;
-    }
-
     /**
      * Main method
      *
diff --git a/src/main/java/com/thealgorithms/sorts/ExchangeSort.java b/src/main/java/com/thealgorithms/sorts/ExchangeSort.java
index 28303430950c..67e94b889671 100644
--- a/src/main/java/com/thealgorithms/sorts/ExchangeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/ExchangeSort.java
@@ -32,16 +32,10 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         for (int i = 0; i < array.length - 1; i++) {
             for (int j = i + 1; j < array.length; j++) {
                 if (array[i].compareTo(array[j]) > 0) {
-                    swap(array, i, j);
+                    SortUtils.swap(array, i, j);
                 }
             }
         }
         return array;
     }
-
-    private <T> void swap(T[] array, int i, int j) {
-        T temp = array[i];
-        array[i] = array[j];
-        array[j] = temp;
-    }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java b/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java
index 930bb02c7ce7..32d942dc78db 100644
--- a/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java
+++ b/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java
@@ -16,12 +16,6 @@ public <T extends Comparable<T>> T[] sort(T[] a) {
         return a;
     }
 
-    private static <T extends Comparable<T>> void swap(T[] a, int i, int j) {
-        T temp = a[i];
-        a[i] = a[j];
-        a[j] = temp;
-    }
-
     private static <T extends Comparable<T>> void introSort(T[] a, int low, int high, int depth) {
         while (high - low > INSERTION_SORT_THRESHOLD) {
             if (depth == 0) {
@@ -37,16 +31,16 @@ private static <T extends Comparable<T>> void introSort(T[] a, int low, int high
 
     private static <T extends Comparable<T>> int partition(T[] a, int low, int high) {
         int pivotIndex = low + (int) (Math.random() * (high - low + 1));
-        swap(a, pivotIndex, high);
+        SortUtils.swap(a, pivotIndex, high);
         T pivot = a[high];
         int i = low - 1;
         for (int j = low; j <= high - 1; j++) {
             if (a[j].compareTo(pivot) <= 0) {
                 i++;
-                swap(a, i, j);
+                SortUtils.swap(a, i, j);
             }
         }
-        swap(a, i + 1, high);
+        SortUtils.swap(a, i + 1, high);
         return i + 1;
     }
 
@@ -67,7 +61,7 @@ private static <T extends Comparable<T>> void heapSort(T[] a, int low, int high)
             heapify(a, i, high - low + 1, low);
         }
         for (int i = high; i > low; i--) {
-            swap(a, low, i);
+            SortUtils.swap(a, low, i);
             heapify(a, low, i - low, low);
         }
     }
@@ -83,7 +77,7 @@ private static <T extends Comparable<T>> void heapify(T[] a, int i, int n, int l
             largest = right;
         }
         if (largest != i) {
-            swap(a, i, largest);
+            SortUtils.swap(a, i, largest);
             heapify(a, largest, n, low);
         }
     }
diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSort.java b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
index e43df7fe622e..cc7b3cc6b662 100644
--- a/src/main/java/com/thealgorithms/sorts/SelectionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.swap;
-
 public class SelectionSort implements SortAlgorithm {
 
     /**
@@ -22,7 +20,7 @@ public <T extends Comparable<T>> T[] sort(T[] arr) {
                 }
             }
             if (minIndex != i) {
-                swap(arr, i, minIndex);
+                SortUtils.swap(arr, i, minIndex);
             }
         }
         return arr;
diff --git a/src/main/java/com/thealgorithms/sorts/SimpleSort.java b/src/main/java/com/thealgorithms/sorts/SimpleSort.java
index 7aab7c784b92..110bc6e4c5b7 100644
--- a/src/main/java/com/thealgorithms/sorts/SimpleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SimpleSort.java
@@ -9,9 +9,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         for (int i = 0; i < length; i++) {
             for (int j = i + 1; j < length; j++) {
                 if (SortUtils.less(array[j], array[i])) {
-                    T element = array[j];
-                    array[j] = array[i];
-                    array[i] = element;
+                    SortUtils.swap(array, i, j);
                 }
             }
         }
diff --git a/src/main/java/com/thealgorithms/sorts/SlowSort.java b/src/main/java/com/thealgorithms/sorts/SlowSort.java
index dcd426b31c0d..38a5fa458778 100644
--- a/src/main/java/com/thealgorithms/sorts/SlowSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SlowSort.java
@@ -20,9 +20,7 @@ private <T extends Comparable<T>> void sort(T[] array, int i, int j) {
         sort(array, i, m);
         sort(array, m + 1, j);
         if (SortUtils.less(array[j], array[m])) {
-            T temp = array[j];
-            array[j] = array[m];
-            array[m] = temp;
+            SortUtils.swap(array, j, m);
         }
         sort(array, i, j - 1);
     }
diff --git a/src/main/java/com/thealgorithms/sorts/SwapSort.java b/src/main/java/com/thealgorithms/sorts/SwapSort.java
index 08ce988578f3..e0fa7087a49e 100644
--- a/src/main/java/com/thealgorithms/sorts/SwapSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SwapSort.java
@@ -18,9 +18,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
             int amountSmallerElements = this.getSmallerElementCount(array, index);
 
             if (amountSmallerElements > 0 && index != amountSmallerElements) {
-                T element = array[index];
-                array[index] = array[amountSmallerElements];
-                array[amountSmallerElements] = element;
+                SortUtils.swap(array, index, amountSmallerElements);
             } else {
                 index++;
             }

From 308bdcfc192768c57071130181db30a1d387d0df Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 22 Jun 2024 23:29:17 +0300
Subject: [PATCH 0213/1338] Refactor: Replace Swap and Comparison Methods with
 SortUtils Utility Methods (#5246)

* Refactor: Replace Swap and Comparison Methods with SortUtils Utility Methods

* Rename parameter unsorted to array

---------

Co-authored-by: Alex Klymenko <alx@alx.com>
---
 .../com/thealgorithms/sorts/HeapSort.java     | 41 ++++++++-----------
 1 file changed, 16 insertions(+), 25 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/HeapSort.java b/src/main/java/com/thealgorithms/sorts/HeapSort.java
index eec705ba476a..91d556b17b16 100644
--- a/src/main/java/com/thealgorithms/sorts/HeapSort.java
+++ b/src/main/java/com/thealgorithms/sorts/HeapSort.java
@@ -9,48 +9,39 @@ public class HeapSort implements SortAlgorithm {
 
     /**
      * For simplicity, we are considering the heap root index as 1 instead of 0.
-     * It simplifies future calculations. Because of that we are decreasing the
-     * provided indexes by 1 in {@link #swap(Object[], int, int)} and
-     * {@link #less(Comparable[], int, int)} functions.
+     * This approach simplifies future calculations. As a result, we decrease
+     * the indexes by 1 when calling {@link SortUtils#less(Comparable, Comparable)}
+     * and provide adjusted values to the {@link SortUtils#swap(Object[], int, int)} methods.
      */
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] unsorted) {
-        int n = unsorted.length;
-        heapify(unsorted, n);
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        int n = array.length;
+        heapify(array, n);
         while (n > 1) {
-            swap(unsorted, 1, n--);
-            siftDown(unsorted, 1, n);
+            SortUtils.swap(array, 0, n - 1);
+            n--;
+            siftDown(array, 1, n);
         }
-        return unsorted;
+        return array;
     }
 
-    private static <T extends Comparable<T>> void heapify(T[] unsorted, int n) {
+    private static <T extends Comparable<T>> void heapify(T[] array, int n) {
         for (int k = n / 2; k >= 1; k--) {
-            siftDown(unsorted, k, n);
+            siftDown(array, k, n);
         }
     }
 
-    private static <T extends Comparable<T>> void siftDown(T[] unsorted, int k, int n) {
+    private static <T extends Comparable<T>> void siftDown(T[] array, int k, int n) {
         while (2 * k <= n) {
             int j = 2 * k;
-            if (j < n && less(unsorted, j, j + 1)) {
+            if (j < n && SortUtils.less(array[j - 1], array[j])) {
                 j++;
             }
-            if (!less(unsorted, k, j)) {
+            if (!SortUtils.less(array[k - 1], array[j - 1])) {
                 break;
             }
-            swap(unsorted, k, j);
+            SortUtils.swap(array, k - 1, j - 1);
             k = j;
         }
     }
-
-    private static <T> void swap(T[] array, int idx, int idy) {
-        T swap = array[idx - 1];
-        array[idx - 1] = array[idy - 1];
-        array[idy - 1] = swap;
-    }
-
-    private static <T extends Comparable<T>> boolean less(T[] array, int idx, int idy) {
-        return array[idx - 1].compareTo(array[idy - 1]) < 0;
-    }
 }

From a5b4c6173f711ddc6a73350d9db2deca625ed762 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 24 Jun 2024 09:49:01 +0300
Subject: [PATCH 0214/1338] fix: avoid infinite loop in `SwapSort` (#5248)

---------

Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/sorts/SwapSort.java     | 38 ++-----------------
 .../com/thealgorithms/sorts/SwapSortTest.java |  8 ++++
 2 files changed, 11 insertions(+), 35 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/sorts/SwapSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/SwapSort.java b/src/main/java/com/thealgorithms/sorts/SwapSort.java
index e0fa7087a49e..fe3597c0e2b4 100644
--- a/src/main/java/com/thealgorithms/sorts/SwapSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SwapSort.java
@@ -17,8 +17,8 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         while (index < len - 1) {
             int amountSmallerElements = this.getSmallerElementCount(array, index);
 
-            if (amountSmallerElements > 0 && index != amountSmallerElements) {
-                SortUtils.swap(array, index, amountSmallerElements);
+            if (amountSmallerElements > 0) {
+                SortUtils.swap(array, index, index + amountSmallerElements);
             } else {
                 index++;
             }
@@ -29,7 +29,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
 
     private <T extends Comparable<T>> int getSmallerElementCount(T[] array, int index) {
         int counter = 0;
-        for (int i = 0; i < array.length; i++) {
+        for (int i = index + 1; i < array.length; i++) {
             if (SortUtils.less(array[i], array[index])) {
                 counter++;
             }
@@ -37,36 +37,4 @@ private <T extends Comparable<T>> int getSmallerElementCount(T[] array, int inde
 
         return counter;
     }
-
-    public static void main(String[] args) {
-        // ==== Int =======
-        Integer[] a = {3, 7, 45, 1, 33, 5, 2, 9};
-        System.out.print("unsorted: ");
-        SortUtils.print(a);
-        System.out.println();
-
-        new SwapSort().sort(a);
-        System.out.print("sorted: ");
-        SortUtils.print(a);
-        System.out.println();
-
-        // ==== String =======
-        String[] b = {
-            "banana",
-            "berry",
-            "orange",
-            "grape",
-            "peach",
-            "cherry",
-            "apple",
-            "pineapple",
-        };
-        System.out.print("unsorted: ");
-        SortUtils.print(b);
-        System.out.println();
-
-        new SwapSort().sort(b);
-        System.out.print("sorted: ");
-        SortUtils.print(b);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/SwapSortTest.java b/src/test/java/com/thealgorithms/sorts/SwapSortTest.java
new file mode 100644
index 000000000000..c1638a385940
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/SwapSortTest.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.sorts;
+
+public class SwapSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new SwapSort();
+    }
+}

From 7b17ead902395e1494df9686ea6d128767956ea4 Mon Sep 17 00:00:00 2001
From: abdala-elgendy <111305293+abdala-elgendy@users.noreply.github.com>
Date: Mon, 24 Jun 2024 11:42:29 +0300
Subject: [PATCH 0215/1338] chore: improve FibonacciHeap (#5251)

---
 .../thealgorithms/datastructures/heaps/FibonacciHeap.java | 8 ++++----
 .../com/thealgorithms/datastructures/heaps/MaxHeap.java   | 2 +-
 .../com/thealgorithms/datastructures/heaps/MinHeap.java   | 2 +-
 .../datastructures/heaps/MinPriorityQueue.java            | 6 +++---
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
index 4734483b518b..d248bc3316ed 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
@@ -8,7 +8,7 @@ public class FibonacciHeap {
     private static int totalCuts = 0;
     private int numOfTrees = 0;
     private int numOfHeapNodes = 0;
-    private int markedHeapNoodesCounter = 0;
+    private int markedHeapNodesCounter = 0;
 
     /*
      * a constructor for an empty Heap
@@ -190,7 +190,7 @@ private void decreaseKey(HeapNode x, int delta) {
      * Potential = #trees + 2*#markedNodes
      */
     public int potential() {
-        return numOfTrees + (2 * markedHeapNoodesCounter);
+        return numOfTrees + (2 * markedHeapNodesCounter);
     }
 
     /**
@@ -232,7 +232,7 @@ private void cascadingCuts(HeapNode curr) {
         if (!curr.isMarked()) { // stop the recursion
             curr.mark();
             if (!curr.isRoot()) {
-                this.markedHeapNoodesCounter++;
+                this.markedHeapNodesCounter++;
             }
         } else {
             if (curr.isRoot()) {
@@ -252,7 +252,7 @@ private void cascadingCuts(HeapNode curr) {
     private void cut(HeapNode curr) {
         curr.parent.rank--;
         if (curr.marked) {
-            this.markedHeapNoodesCounter--;
+            this.markedHeapNodesCounter--;
             curr.marked = false;
         }
         if (curr.parent.child == curr) { // we should change the parent's child
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
index 067aae738914..9010aae4cae5 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
@@ -22,7 +22,7 @@ public MaxHeap(List<HeapElement> listElements) {
                 System.out.println("Null element. Not added to heap");
             }
         }
-        if (maxHeap.size() == 0) {
+        if (maxHeap.isEmpty()) {
             System.out.println("No element has been added, empty heap.");
         }
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
index 6e972205acfe..46864fba0047 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
@@ -22,7 +22,7 @@ public MinHeap(List<HeapElement> listElements) {
                 System.out.println("Null element. Not added to heap");
             }
         }
-        if (minHeap.size() == 0) {
+        if (minHeap.isEmpty()) {
             System.out.println("No element has been added, empty heap.");
         }
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java b/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java
index 2ad4ed5320c9..9d19e9aaee1a 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java
@@ -14,11 +14,11 @@
  */
 public class MinPriorityQueue {
 
-    private int[] heap;
-    private int capacity;
+    private final int[] heap;
+    private final int capacity;
     private int size;
 
-    // calss the constructor and initializes the capacity
+    // class the constructor and initializes the capacity
     MinPriorityQueue(int c) {
         this.capacity = c;
         this.size = 0;

From 22f2abd94f81582a547c9352c136b27c22db08d7 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 24 Jun 2024 10:47:33 +0200
Subject: [PATCH 0216/1338] style: enable `WhitespaceAround` in checktyle
 (#5241)

---
 checkstyle.xml                                                 | 2 +-
 .../java/com/thealgorithms/dynamicprogramming/UniquePaths.java | 3 ++-
 src/test/java/com/thealgorithms/maths/MeansTest.java           | 2 +-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index af5e3527e32f..4fc237d29c5a 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -143,7 +143,7 @@
     <module name="ParenPad"/>
     <module name="TypecastParenPad"/>
     <module name="WhitespaceAfter"/>
-    <!-- TODO <module name="WhitespaceAround"/> -->
+    <module name="WhitespaceAround"/>
 
     <!-- Modifier Checks                                    -->
     <!-- See https://checkstyle.org/checks/modifier/index.html -->
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java b/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java
index c48bdea2dc8d..80b553f2744c 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java
@@ -19,7 +19,8 @@
 
 public final class UniquePaths {
 
-    private UniquePaths(){};
+    private UniquePaths() {
+    }
 
     /**
      * Calculates the number of unique paths using a 1D dynamic programming array.
diff --git a/src/test/java/com/thealgorithms/maths/MeansTest.java b/src/test/java/com/thealgorithms/maths/MeansTest.java
index a1c07e25bea3..bb2b4b6d1c50 100644
--- a/src/test/java/com/thealgorithms/maths/MeansTest.java
+++ b/src/test/java/com/thealgorithms/maths/MeansTest.java
@@ -59,7 +59,7 @@ void arithmeticMeanMultipleNumbers() {
 
     @Test
     void geometricMeanMultipleNumbers() {
-        LinkedList<Double> numbers = new LinkedList<>() {};
+        LinkedList<Double> numbers = new LinkedList<>();
         numbers.addAll(Lists.newArrayList(1d, 2d, 3d, 4d, 5d, 6d, 1.25));
         assertEquals(2.6426195539300585, Means.geometric(numbers));
     }

From a710fe11c47bdfb80342f851c189d167035b7b1c Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 24 Jun 2024 10:49:50 +0200
Subject: [PATCH 0217/1338] style: include `SPP_USE_ISEMPTY` (#5238)

---
 spotbugs-exclude.xml                                        | 3 ---
 .../com/thealgorithms/devutils/nodes/LargeTreeNode.java     | 2 +-
 src/main/java/com/thealgorithms/searches/QuickSelect.java   | 2 +-
 .../java/com/thealgorithms/sorts/MergeSortRecursive.java    | 6 +++---
 4 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 0a5354382a4f..9a9712e0a571 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -132,9 +132,6 @@
     <Match>
         <Bug pattern="USBR_UNNECESSARY_STORE_BEFORE_RETURN" />
     </Match>
-    <Match>
-        <Bug pattern="SPP_USE_ISEMPTY" />
-    </Match>
     <Match>
         <Bug pattern="BL_BURYING_LOGIC" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/devutils/nodes/LargeTreeNode.java b/src/main/java/com/thealgorithms/devutils/nodes/LargeTreeNode.java
index 1575e3649bc3..95d53ecb1f7a 100644
--- a/src/main/java/com/thealgorithms/devutils/nodes/LargeTreeNode.java
+++ b/src/main/java/com/thealgorithms/devutils/nodes/LargeTreeNode.java
@@ -64,7 +64,7 @@ public LargeTreeNode(E data, LargeTreeNode<E> parentNode, Collection<LargeTreeNo
      */
     @Override
     public boolean isLeafNode() {
-        return (childNodes == null || childNodes.size() == 0);
+        return (childNodes == null || childNodes.isEmpty());
     }
 
     public Collection<LargeTreeNode<E>> getChildNodes() {
diff --git a/src/main/java/com/thealgorithms/searches/QuickSelect.java b/src/main/java/com/thealgorithms/searches/QuickSelect.java
index c89abb00e9da..d5f695293a6a 100644
--- a/src/main/java/com/thealgorithms/searches/QuickSelect.java
+++ b/src/main/java/com/thealgorithms/searches/QuickSelect.java
@@ -31,7 +31,7 @@ private QuickSelect() {
     public static <T extends Comparable<T>> T select(List<T> list, int n) {
         Objects.requireNonNull(list, "The list of elements must not be null.");
 
-        if (list.size() == 0) {
+        if (list.isEmpty()) {
             String msg = "The list of elements must not be empty.";
             throw new IllegalArgumentException(msg);
         }
diff --git a/src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java b/src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java
index f67ba631be0e..910157b83231 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java
@@ -34,13 +34,13 @@ private static List<Integer> merge(List<Integer> arr) {
     }
 
     private static List<Integer> sort(List<Integer> unsortedA, List<Integer> unsortedB) {
-        if (unsortedA.size() <= 0 && unsortedB.size() <= 0) {
+        if (unsortedA.isEmpty() && unsortedB.isEmpty()) {
             return new ArrayList<>();
         }
-        if (unsortedA.size() <= 0) {
+        if (unsortedA.isEmpty()) {
             return unsortedB;
         }
-        if (unsortedB.size() <= 0) {
+        if (unsortedB.isEmpty()) {
             return unsortedA;
         }
         if (unsortedA.get(0) <= unsortedB.get(0)) {

From d36f54bd396789ec7b95350285ce5d1b5c7c0972 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 25 Jun 2024 07:07:07 +0200
Subject: [PATCH 0218/1338] style: include `NM_CLASS_NAMING_CONVENTION` and
 `NM_METHOD_NAMING_CONVENTION` (#5231)

---
 spotbugs-exclude.xml | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 9a9712e0a571..111b41720fbb 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -17,9 +17,6 @@
     <Match>
         <Bug pattern="DM_NEXTINT_VIA_NEXTDOUBLE" />
     </Match>
-    <Match>
-        <Bug pattern="NM_CLASS_NAMING_CONVENTION" />
-    </Match>
     <Match>
         <Bug pattern="SIC_INNER_SHOULD_BE_STATIC" />
     </Match>
@@ -44,9 +41,6 @@
     <Match>
         <Bug pattern="INT_BAD_REM_BY_1" />
     </Match>
-    <Match>
-        <Bug pattern="NM_METHOD_NAMING_CONVENTION" />
-    </Match>
     <Match>
         <Bug pattern="ICAST_IDIV_CAST_TO_DOUBLE" />
     </Match>

From cff3a59530f759fa98423983711c54021f0bbe45 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 25 Jun 2024 08:51:24 +0200
Subject: [PATCH 0219/1338] style: include `BED_BOGUS_EXCEPTION_DECLARATION`
 (#5233)

---
 spotbugs-exclude.xml                                      | 3 ---
 .../java/com/thealgorithms/stacks/DuplicateBrackets.java  | 8 --------
 2 files changed, 11 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 111b41720fbb..f1b48d52829b 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -114,9 +114,6 @@
     <Match>
         <Bug pattern="CLI_CONSTANT_LIST_INDEX" />
     </Match>
-    <Match>
-        <Bug pattern="BED_BOGUS_EXCEPTION_DECLARATION" />
-    </Match>
     <Match>
         <Bug pattern="CNC_COLLECTION_NAMING_CONFUSION" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java b/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
index 2fb03de77de5..482bda0a02a2 100644
--- a/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
+++ b/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
@@ -8,7 +8,6 @@
 // e.g.'
 // ((a + b) + (c + d)) -> false
 // (a + b) + ((c + d)) -> true
-import java.util.Scanner;
 import java.util.Stack;
 
 public final class DuplicateBrackets {
@@ -36,11 +35,4 @@ public static boolean check(String str) {
         }
         return false;
     }
-
-    public static void main(String[] args) throws Exception {
-        Scanner sc = new Scanner(System.in);
-        String str = sc.nextLine();
-        System.out.println(check(str));
-        sc.close();
-    }
 }

From f279f9d589febf61b52bb61caf89d02230e65324 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 25 Jun 2024 07:01:32 +0000
Subject: [PATCH 0220/1338] Chore(deps): bump gitpod/workspace-java-21 from
 2024-06-17-10-03-09 to 2024-06-24-08-46-07 (#5253)

Dependabot couldn't find the original pull request head commit, a1d54164dac1d97b56d75099b00f7db58bf8fb48.

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 0718384d33ff..31b013937b4e 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-06-17-10-03-09
+FROM gitpod/workspace-java-21:2024-06-24-08-46-07
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 971f5fc85bd7d80c83c4cf7da5854029cd30bf91 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 26 Jun 2024 08:48:20 +0200
Subject: [PATCH 0221/1338] Chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.8.5.0 to 4.8.6.0 (#5256)

Chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.8.5.0 to 4.8.6.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.8.5.0...spotbugs-maven-plugin-4.8.6.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 6f28c62b5099..67d16dfccca2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.8.5.0</version>
+                <version>4.8.6.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 7054535d36a14e4fa17ef7f236f710ab7b9f8b4b Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 26 Jun 2024 23:41:54 +0300
Subject: [PATCH 0222/1338] feat: add `WaveSort` (#5252)

* Implementing WaveSort Algorithm

* Refactor: Tests to ParameterizedTest

* Checkstyle: Fix wrong align

* Checkstyle: Fix wrong align for second line

* Checkstyle: Remove redundant line

* Naming: fix method name

* Documentation: adding links

* Fix: adding test for isWaveSorted method

* Documentation: adding description for WaveSort

* Testing: test wave sort assert

* Checkstyle: remove redundant whitespace

* Checkstyle: remove redundant newline

* Testing: improving tests

---------

Co-authored-by: alxklm <alx@alx.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 DIRECTORY.md                                  |  2 +
 .../com/thealgorithms/sorts/WaveSort.java     | 46 ++++++++++++++++++
 .../com/thealgorithms/sorts/WaveSortTest.java | 48 +++++++++++++++++++
 3 files changed, 96 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/WaveSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/WaveSortTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7c46336f0911..c4eb2a6d30aa 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -528,6 +528,7 @@
             * [TopologicalSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/TopologicalSort.java)
             * [TreeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/TreeSort.java)
             * [WiggleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/WiggleSort.java)
+            * [WaveSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/WaveSort.java)
           * stacks
             * [BalancedBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java)
             * [DecimalToAnyUsingStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java)
@@ -885,6 +886,7 @@
             * [TopologicalSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java)
             * [TreeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TreeSortTest.java)
             * [WiggleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java)
+            * [WaveSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WaveSortTest.java)
           * stacks
             * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
           * strings
diff --git a/src/main/java/com/thealgorithms/sorts/WaveSort.java b/src/main/java/com/thealgorithms/sorts/WaveSort.java
new file mode 100644
index 000000000000..31aad52c6b4a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/WaveSort.java
@@ -0,0 +1,46 @@
+package com.thealgorithms.sorts;
+
+/**
+ * The WaveSort algorithm sorts an array so that every alternate element is greater than its adjacent elements.
+ * This implementation also provides a method to check if an array is wave sorted.
+ */
+public class WaveSort implements SortAlgorithm {
+    /**
+     * Sorts the given array such that every alternate element is greater than its adjacent elements.
+     *
+     * @param array The array to be sorted.
+     * @param <T> The type of elements in the array, which must be Comparable.
+     * @return The sorted array.
+     */
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        for (int i = 0; i < array.length; i += 2) {
+            if (i > 0 && SortUtils.less(array[i], array[i - 1])) {
+                SortUtils.swap(array, i, i - 1);
+            }
+            if (i < array.length - 1 && SortUtils.less(array[i], array[i + 1])) {
+                SortUtils.swap(array, i, i + 1);
+            }
+        }
+        return array;
+    }
+
+    /**
+     * Checks if the given array is wave sorted. An array is wave sorted if every alternate element is greater than its adjacent elements.
+     *
+     * @param array The array to check.
+     * @param <T> The type of elements in the array, which must be Comparable.
+     * @return true if the array is wave sorted, false otherwise.
+     */
+    public <T extends Comparable<T>> boolean isWaveSorted(T[] array) {
+        for (int i = 0; i < array.length; i += 2) {
+            if (i > 0 && SortUtils.less(array[i], array[i - 1])) {
+                return false;
+            }
+            if (i < array.length - 1 && SortUtils.less(array[i], array[i + 1])) {
+                return false;
+            }
+        }
+        return true;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/WaveSortTest.java b/src/test/java/com/thealgorithms/sorts/WaveSortTest.java
new file mode 100644
index 000000000000..3bc6fa63c01d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/WaveSortTest.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class WaveSortTest {
+    @ParameterizedTest
+    @MethodSource("arraysToWaveSort")
+    public void waveSortTest(Integer[] array) {
+        WaveSort waveSort = new WaveSort();
+        final var inputHistogram = getHistogram(array);
+        final var sortedArray = waveSort.sort(array);
+        assertTrue(waveSort.isWaveSorted(sortedArray));
+        final var sortedHistogram = getHistogram(sortedArray);
+        assertEquals(inputHistogram, sortedHistogram, "Element counts do not match");
+    }
+
+    private Map<Integer, Integer> getHistogram(Integer[] array) {
+        Map<Integer, Integer> histogram = new HashMap<>();
+        for (final var element : array) {
+            histogram.put(element, histogram.getOrDefault(element, 0) + 1);
+        }
+        return histogram;
+    }
+
+    private static Stream<Object[]> arraysToWaveSort() {
+        return Stream.of(new Object[] {new Integer[] {7, 7, 11, 3, 4, 5, 15}}, new Object[] {new Integer[] {1, 2, 3, 4, 5, 6, 7, 8}}, new Object[] {new Integer[] {8, 7, 6, 5, 4, 3, 2, 1}}, new Object[] {new Integer[] {3, 3, 3, 3}}, new Object[] {new Integer[] {-1, -3, -2, -4, -6, -5}},
+            new Object[] {new Integer[] {5, 3, 1, 2, 9, 7, 6, 8, 4, 0}}, new Object[] {new Integer[] {1}}, new Object[] {new Integer[] {2, 1}}, new Object[] {new Integer[] {1, 2}}, new Object[] {new Integer[] {}}, new Object[] {new Integer[] {0, 5, -3, 2, -1, 4, -2, 1, 3}});
+    }
+
+    @ParameterizedTest
+    @MethodSource("waveSortedArrays")
+    public <T extends Comparable<T>> void testIsWaveSorted(T[] array, boolean expected) {
+        final WaveSort waveSort = new WaveSort();
+        assertEquals(expected, waveSort.isWaveSorted(array));
+    }
+    public static Stream<Object[]> waveSortedArrays() {
+        return Stream.of(new Object[] {new Integer[] {3, 1, 4, 2, 5}, Boolean.TRUE}, new Object[] {new Integer[] {3, 1, 4, 2}, Boolean.TRUE}, new Object[] {new Integer[] {1, 3, 2, 4, 5}, Boolean.FALSE}, new Object[] {new Integer[] {4, 3, 5, 2, 3, 1, 2}, Boolean.TRUE},
+            new Object[] {new Integer[] {10, 90, 49, 2, 1, 5, 23}, Boolean.FALSE}, new Object[] {new Integer[] {}, Boolean.TRUE}, new Object[] {new Integer[] {1}, Boolean.TRUE}, new Object[] {new Integer[] {2, 1}, Boolean.TRUE}, new Object[] {new Integer[] {4, 3, 2, 5}, Boolean.FALSE},
+            new Object[] {new Double[] {4.0, 3.0, 5.1, 2.1, 3.3, 1.1, 2.2}, Boolean.TRUE}, new Object[] {new Double[] {10.1, 2.0, 2.0}, Boolean.TRUE}, new Object[] {new String[] {"a", "b", "c", "d"}, Boolean.FALSE}, new Object[] {new String[] {"b", "a", "b", "a", "b"}, Boolean.TRUE});
+    }
+}

From cba28d31c52a4467b81c3d95f68f08a4fb6ced50 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 28 Jun 2024 08:52:27 +0200
Subject: [PATCH 0223/1338] Chore(deps): bump org.junit:junit-bom from 5.10.2
 to 5.10.3 (#5260)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.10.2 to 5.10.3.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.10.2...r5.10.3)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 67d16dfccca2..78b0dbb1b6f4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.10.2</version>
+                <version>5.10.3</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 69f221683f3fb13c32682a477f3ddc65fdc50d99 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 28 Jun 2024 08:56:46 +0200
Subject: [PATCH 0224/1338] Chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.8.6.0 to 4.8.6.1 (#5261)

Chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.8.6.0 to 4.8.6.1.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.8.6.0...spotbugs-maven-plugin-4.8.6.1)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 78b0dbb1b6f4..56b76ed6be72 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.8.6.0</version>
+                <version>4.8.6.1</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From c2a5c919207c7d1914a2c52f1bda8e9b505fcd2e Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 28 Jun 2024 06:59:21 +0000
Subject: [PATCH 0225/1338] Chore(deps-dev): bump
 org.junit.jupiter:junit-jupiter-api from 5.10.2 to 5.10.3 (#5263)

Chore(deps-dev): bump org.junit.jupiter:junit-jupiter-api

Bumps [org.junit.jupiter:junit-jupiter-api](https://github.com/junit-team/junit5) from 5.10.2 to 5.10.3.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.10.2...r5.10.3)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter-api
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 56b76ed6be72..37ad3e1bb9dd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -44,7 +44,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>5.10.2</version>
+            <version>5.10.3</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 224ee3d2272e92a6ff91af0b9bca63393044e636 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 28 Jun 2024 07:01:39 +0000
Subject: [PATCH 0226/1338] Chore(deps-dev): bump
 org.junit.jupiter:junit-jupiter from 5.10.2 to 5.10.3 (#5262)

Chore(deps-dev): bump org.junit.jupiter:junit-jupiter

Bumps [org.junit.jupiter:junit-jupiter](https://github.com/junit-team/junit5) from 5.10.2 to 5.10.3.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.10.2...r5.10.3)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 37ad3e1bb9dd..924a736d526d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.10.2</version>
+            <version>5.10.3</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 0087444e9f8a0212f8ae5ba09d2966b91004d225 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 28 Jun 2024 10:18:06 +0300
Subject: [PATCH 0227/1338] feat: add `SelectionSortRecursive` (#5255)

* Implementation: SelectionSort using recursion

* Documentation: adding links

* Fix issue with findMinIndex

* Fix: change findMinIndex method to recursive

* Fix: improve variable change scope

* Fix: Replacing recursive method findMinIndex with iterative. To fix StackOverFlow on huge arrays

* refactor: remove `null` check

* Fix: Removing redundant null check

---------

Co-authored-by: alxklm <alx@alx.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 DIRECTORY.md                                  |  2 +
 .../sorts/SelectionSortRecursive.java         | 66 +++++++++++++++++++
 .../sorts/SelectionSortRecursiveTest.java     |  8 +++
 3 files changed, 76 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index c4eb2a6d30aa..c033fe307ab2 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -515,6 +515,7 @@
             * [QuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/QuickSort.java)
             * [RadixSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/RadixSort.java)
             * [SelectionSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SelectionSort.java)
+            * [SelectionSortRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java)
             * [ShellSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/ShellSort.java)
             * [SimpleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SimpleSort.java)
             * [SlowSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SlowSort.java)
@@ -875,6 +876,7 @@
             * [PancakeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java)
             * [QuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/QuickSortTest.java)
             * [SelectionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java)
+            * [SelectionSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java)
             * [ShellSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/ShellSortTest.java)
             * [SimpleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SimpleSortTest.java)
             * [SlowSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SlowSortTest.java)
diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java b/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
new file mode 100644
index 000000000000..1326bb5e73da
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
@@ -0,0 +1,66 @@
+package com.thealgorithms.sorts;
+
+/**
+ * Class that implements the Selection Sort algorithm using recursion.
+ */
+public class SelectionSortRecursive implements SortAlgorithm {
+
+    /**
+     * Sorts an array using recursive selection sort.
+     *
+     * @param array the array to be sorted
+     * @param <T>   the type of elements in the array (must be Comparable)
+     * @return the sorted array
+     */
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array.length == 0) {
+            return array;
+        }
+        recursiveSelectionSort(array, 0);
+        return array;
+    }
+
+    /**
+     * Recursively sorts the array using selection sort.
+     *
+     * @param array the array to be sorted
+     * @param index the current index to start sorting from
+     * @param <T>   the type of elements in the array (must be Comparable)
+     */
+    private static <T extends Comparable<T>> void recursiveSelectionSort(T[] array, int index) {
+        if (index == array.length - 1) {
+            return;
+        }
+
+        // Find the minimum element in the remaining unsorted array
+        final int minIndex = findMinIndex(array, index);
+
+        // Swap the found minimum element with the element at the current index
+        if (minIndex != index) {
+            SortUtils.swap(array, index, minIndex);
+        }
+
+        // Recursively call selection sort for the remaining array
+        recursiveSelectionSort(array, index + 1);
+    }
+
+    /**
+     * Finds the index of the minimum element in the array starting from the given index.
+     *
+     * @param array the array to search in.
+     * @param start the starting index.
+     * @param <T> the type of the elements in the array, which must be Comparable.
+     * @return the index of the minimum element starting from the given index.
+     */
+    private static <T extends Comparable<T>> int findMinIndex(T[] array, int start) {
+        int currentMinIndex = start;
+
+        for (int currentIndex = start + 1; currentIndex < array.length; currentIndex++) {
+            if (array[currentIndex].compareTo(array[currentMinIndex]) < 0) {
+                currentMinIndex = currentIndex;
+            }
+        }
+
+        return currentMinIndex;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java b/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java
new file mode 100644
index 000000000000..48025f4ce4f4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.sorts;
+
+public class SelectionSortRecursiveTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new SelectionSortRecursive();
+    }
+}

From 20e7a3aca475ec9afea8f009cdb84bdf55a4420b Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 29 Jun 2024 11:04:58 +0300
Subject: [PATCH 0228/1338] refactor: `SelectionSort` like classes and their
 tests (#5265)

* Refactor: Adding test common approach, adding javadocs, renaming variables

* Refactor: Fix failed build, when generated test case for recursion is too big. To avoid stackoverflow

* Checkstyle: Adding newline to end of class

* refactor: simplify assign minIndex in recursiveSelectionSort, and improving SelectionSort

* checkstyle: adding newline to SelectionSort

---------

Co-authored-by: Alex Klymenko <alx@alx.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../thealgorithms/sorts/SelectionSort.java    | 51 +++++++------------
 .../sorts/SelectionSortRecursive.java         | 31 +++++------
 .../sorts/SelectionSortRecursiveTest.java     |  4 ++
 .../sorts/SelectionSortTest.java              | 35 ++-----------
 .../sorts/SortingAlgorithmTest.java           |  8 ++-
 5 files changed, 45 insertions(+), 84 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSort.java b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
index cc7b3cc6b662..8c815c6cb5fc 100644
--- a/src/main/java/com/thealgorithms/sorts/SelectionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
@@ -1,46 +1,31 @@
 package com.thealgorithms.sorts;
 
 public class SelectionSort implements SortAlgorithm {
-
     /**
-     * Generic selection sort algorithm in increasing order.
+     * Sorts an array of comparable elements in increasing order using the selection sort algorithm.
      *
-     * @param arr the array to be sorted.
-     * @param <T> the class of array.
-     * @return sorted array.
+     * @param array the array to be sorted
+     * @param <T> the class of array elements
+     * @return the sorted array
      */
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] arr) {
-        int n = arr.length;
-        for (int i = 0; i < n - 1; i++) {
-            int minIndex = i;
-            for (int j = i + 1; j < n; j++) {
-                if (arr[minIndex].compareTo(arr[j]) > 0) {
-                    minIndex = j;
-                }
-            }
-            if (minIndex != i) {
-                SortUtils.swap(arr, i, minIndex);
-            }
-        }
-        return arr;
-    }
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        // One by one move the boundary of the unsorted subarray
+        for (int i = 0; i < array.length - 1; i++) {
 
-    /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        Integer[] arr = {4, 23, 6, 78, 1, 54, 231, 9, 12};
-        SelectionSort selectionSort = new SelectionSort();
-        Integer[] sorted = selectionSort.sort(arr);
-        for (int i = 0; i < sorted.length - 1; ++i) {
-            assert sorted[i] <= sorted[i + 1];
+            // Swap the remaining minimum element with the current element
+            SortUtils.swap(array, i, findIndexOfMin(array, i));
         }
+        return array;
+    }
 
-        String[] strings = {"c", "a", "e", "b", "d"};
-        String[] sortedStrings = selectionSort.sort(strings);
-        for (int i = 0; i < sortedStrings.length - 1; ++i) {
-            assert strings[i].compareTo(strings[i + 1]) <= 0;
+    private static <T extends Comparable<T>> int findIndexOfMin(T[] array, final int start) {
+        int minIndex = start;
+        for (int i = start + 1; i < array.length; i++) {
+            if (array[i].compareTo(array[minIndex]) < 0) {
+                minIndex = i;
+            }
         }
+        return minIndex;
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java b/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
index 1326bb5e73da..32bd58a1361a 100644
--- a/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
@@ -32,13 +32,7 @@ private static <T extends Comparable<T>> void recursiveSelectionSort(T[] array,
             return;
         }
 
-        // Find the minimum element in the remaining unsorted array
-        final int minIndex = findMinIndex(array, index);
-
-        // Swap the found minimum element with the element at the current index
-        if (minIndex != index) {
-            SortUtils.swap(array, index, minIndex);
-        }
+        SortUtils.swap(array, index, findMinIndex(array, index));
 
         // Recursively call selection sort for the remaining array
         recursiveSelectionSort(array, index + 1);
@@ -47,20 +41,21 @@ private static <T extends Comparable<T>> void recursiveSelectionSort(T[] array,
     /**
      * Finds the index of the minimum element in the array starting from the given index.
      *
-     * @param array the array to search in.
-     * @param start the starting index.
-     * @param <T> the type of the elements in the array, which must be Comparable.
-     * @return the index of the minimum element starting from the given index.
+     * @param array the array to search
+     * @param start the starting index for the search
+     * @param <T>   the type of elements in the array
+     * @return the index of the minimum element
      */
     private static <T extends Comparable<T>> int findMinIndex(T[] array, int start) {
-        int currentMinIndex = start;
-
-        for (int currentIndex = start + 1; currentIndex < array.length; currentIndex++) {
-            if (array[currentIndex].compareTo(array[currentMinIndex]) < 0) {
-                currentMinIndex = currentIndex;
-            }
+        // Base case: if start is the last index, return start
+        if (start == array.length - 1) {
+            return start;
         }
 
-        return currentMinIndex;
+        // Recursive call to find the minimum index in the rest of the array
+        final int minIndexInRest = findMinIndex(array, start + 1);
+
+        // Return the index of the smaller element between array[start] and the minimum element in the rest of the array
+        return array[start].compareTo(array[minIndexInRest]) < 0 ? start : minIndexInRest;
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java b/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java
index 48025f4ce4f4..20dcf249b31a 100644
--- a/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java
@@ -5,4 +5,8 @@ public class SelectionSortRecursiveTest extends SortingAlgorithmTest {
     SortAlgorithm getSortAlgorithm() {
         return new SelectionSortRecursive();
     }
+
+    protected int getGeneratedArraySize() {
+        return 5000;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java b/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java
index 83fbd1ece909..fab4be1ad01b 100644
--- a/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java
@@ -1,35 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-
-import org.junit.jupiter.api.Test;
-
-class SelectionSortTest {
-
-    @Test
-    // valid test case
-    void integerArrTest() {
-        Integer[] arr = {4, 23, 6, 78, 1, 54, 231, 9, 12};
-        SelectionSort selectionSort = new SelectionSort();
-
-        assertArrayEquals(new Integer[] {1, 4, 6, 9, 12, 23, 54, 78, 231}, selectionSort.sort(arr));
-    }
-
-    @Test
-    // valid test case
-    void stringArrTest() {
-        String[] arr = {"c", "a", "e", "b", "d"};
-        SelectionSort selectionSort = new SelectionSort();
-
-        assertArrayEquals(new String[] {"a", "b", "c", "d", "e"}, selectionSort.sort(arr));
-    }
-
-    @Test
-    // invalid test case
-    void emptyArrTest() {
-        Integer[] arr = {};
-        SelectionSort selectionSort = new SelectionSort();
-
-        assertArrayEquals(new Integer[] {}, selectionSort.sort(arr));
+class SelectionSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new SelectionSort();
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java b/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java
index 113bff2b5b0d..e6aedc3f06ac 100644
--- a/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java
@@ -11,6 +11,10 @@
 public abstract class SortingAlgorithmTest {
     abstract SortAlgorithm getSortAlgorithm();
 
+    protected int getGeneratedArraySize() {
+        return 10_000;
+    }
+
     @Test
     void shouldAcceptWhenEmptyArrayIsPassed() {
         Integer[] array = new Integer[] {};
@@ -153,7 +157,7 @@ void shouldAcceptWhenStringValueListIsPassed() {
 
     @Test
     void shouldAcceptWhenRandomArrayIsPassed() {
-        int randomSize = SortUtilsRandomGenerator.generateInt(10_000);
+        int randomSize = SortUtilsRandomGenerator.generateInt(getGeneratedArraySize());
         Double[] array = SortUtilsRandomGenerator.generateArray(randomSize);
         Double[] sorted = getSortAlgorithm().sort(array);
         assertTrue(SortUtils.isSorted(sorted));
@@ -161,7 +165,7 @@ void shouldAcceptWhenRandomArrayIsPassed() {
 
     @Test
     void shouldAcceptWhenRandomListIsPassed() {
-        int randomSize = SortUtilsRandomGenerator.generateInt(10_000);
+        int randomSize = SortUtilsRandomGenerator.generateInt(getGeneratedArraySize());
         Double[] array = SortUtilsRandomGenerator.generateArray(randomSize);
         List<Double> list = List.of(array);
         List<Double> sorted = getSortAlgorithm().sort(list);

From 758df7dcc3cf8c34bd37618b2c1d2cad75bc8a51 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 29 Jun 2024 23:33:40 +0300
Subject: [PATCH 0229/1338] feat: optimize `SortUtils.swap` by skipping
 operations for equal indices (#5266)

* Refactor: adding check to swap method in SortUtils

* Checkstyle: fix formatting

* Checkstyle: fix formatting, and redundant braces

* fix: adding flipped tests, removed messages from tests

* checkstyle: fix indent

* style: mark `temp` as `final`

* tests: remove test case with empty array

Such calls should be excluded.

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/sorts/SortUtils.java    |  8 ++++---
 .../thealgorithms/sorts/SortUtilsTest.java    | 24 +++++++++++++++++++
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/SortUtils.java b/src/main/java/com/thealgorithms/sorts/SortUtils.java
index fda1975189ec..9e51c3d9e09a 100644
--- a/src/main/java/com/thealgorithms/sorts/SortUtils.java
+++ b/src/main/java/com/thealgorithms/sorts/SortUtils.java
@@ -17,9 +17,11 @@ private SortUtils() {
      * @param <T>   the type of elements in the array
      */
     public static <T> void swap(T[] array, int i, int j) {
-        T temp = array[i];
-        array[i] = array[j];
-        array[j] = temp;
+        if (i != j) {
+            final T temp = array[i];
+            array[i] = array[j];
+            array[j] = temp;
+        }
     }
 
     /**
diff --git a/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java b/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java
index 591b53891ee7..ac654148c967 100644
--- a/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java
@@ -1,10 +1,15 @@
 package com.thealgorithms.sorts;
 
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
+import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class SortUtilsTest {
 
@@ -67,4 +72,23 @@ void isSortedListFalse() {
         List<Integer> array3 = List.of(5, 4, 3, 2, 1);
         assertFalse(SortUtils.isSorted(array3));
     }
+
+    @ParameterizedTest
+    @MethodSource("provideArraysForSwap")
+    public <T> void testSwap(T[] array, int i, int j, T[] expected) {
+        SortUtils.swap(array, i, j);
+        assertArrayEquals(expected, array);
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideArraysForSwap")
+    public <T> void testSwapFlippedIndices(T[] array, int i, int j, T[] expected) {
+        SortUtils.swap(array, j, i);
+        assertArrayEquals(expected, array);
+    }
+
+    private static Stream<Arguments> provideArraysForSwap() {
+        return Stream.of(Arguments.of(new Integer[] {1, 2, 3, 4}, 1, 2, new Integer[] {1, 3, 2, 4}), Arguments.of(new Integer[] {1, 2, 3, 4}, 0, 3, new Integer[] {4, 2, 3, 1}), Arguments.of(new Integer[] {1, 2, 3, 4}, 2, 2, new Integer[] {1, 2, 3, 4}),
+            Arguments.of(new String[] {"a", "b", "c", "d"}, 0, 3, new String[] {"d", "b", "c", "a"}), Arguments.of(new String[] {null, "b", "c", null}, 0, 3, new String[] {null, "b", "c", null}));
+    }
 }

From 208e1e99f0ced1a3f3b19371a4f198decf1aac50 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 30 Jun 2024 20:51:11 +0300
Subject: [PATCH 0230/1338] refactor: BubbleSortRecursion: improving naming,
 adding standard test (#5267)

* refactor: improving naming, adding standard test

* style: remove `BubbleSortRecursive` from pmd exclude list

* docs: typo fix

---------

Co-authored-by: Alex Klymenko <alx@alx.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 DIRECTORY.md                                  |  3 +-
 pmd-exclude.properties                        |  1 -
 .../sorts/BubbleSortRecursion.java            | 57 -------------------
 .../sorts/BubbleSortRecursive.java            | 35 ++++++++++++
 .../sorts/BubbleSortRecursiveTest.java        |  8 +++
 5 files changed, 45 insertions(+), 59 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/sorts/BubbleSortRecursion.java
 create mode 100644 src/main/java/com/thealgorithms/sorts/BubbleSortRecursive.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/BubbleSortRecursiveTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index c033fe307ab2..6cecfef02de5 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -490,7 +490,7 @@
             * [BitonicSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BitonicSort.java)
             * [BogoSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BogoSort.java)
             * [BubbleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BubbleSort.java)
-            * [BubbleSortRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BubbleSortRecursion.java)
+            * [BubbleSortRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BubbleSortRecursive.java)
             * [BucketSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BucketSort.java)
             * [CircleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CircleSort.java)
             * [CocktailShakerSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java)
@@ -859,6 +859,7 @@
             * [BinaryInsertionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java)
             * [BogoSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BogoSortTest.java)
             * [BubbleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BubbleSortTest.java)
+            * [BubbleSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BubbleSortRecursiveTest.java)
             * [BucketSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BucketSortTest.java)
             * [CircleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CircleSortTest.java)
             * [CocktailShakerSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java)
diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index eb199da3a0d3..b7bc6f074d02 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -76,7 +76,6 @@ com.thealgorithms.searches.InterpolationSearch=UselessParentheses
 com.thealgorithms.searches.KMPSearch=UselessParentheses
 com.thealgorithms.searches.LinearSearchThread=EmptyCatchBlock
 com.thealgorithms.searches.RabinKarpAlgorithm=UselessParentheses
-com.thealgorithms.sorts.BubbleSortRecursion=UselessParentheses
 com.thealgorithms.sorts.CircleSort=EmptyControlStatement
 com.thealgorithms.sorts.CombSort=UselessParentheses
 com.thealgorithms.sorts.DutchNationalFlagSort=UselessParentheses
diff --git a/src/main/java/com/thealgorithms/sorts/BubbleSortRecursion.java b/src/main/java/com/thealgorithms/sorts/BubbleSortRecursion.java
deleted file mode 100644
index 10197969e853..000000000000
--- a/src/main/java/com/thealgorithms/sorts/BubbleSortRecursion.java
+++ /dev/null
@@ -1,57 +0,0 @@
-package com.thealgorithms.sorts;
-
-import java.util.Random;
-
-/**
- * BubbleSort algorithm implements using recursion
- */
-public class BubbleSortRecursion implements SortAlgorithm {
-
-    public static void main(String[] args) {
-        Integer[] array = new Integer[10];
-
-        Random random = new Random();
-        /* generate 10 random numbers from -50 to 49 */
-        for (int i = 0; i < array.length; ++i) {
-            array[i] = random.nextInt(100) - 50;
-        }
-
-        BubbleSortRecursion bubbleSortRecursion = new BubbleSortRecursion();
-        bubbleSortRecursion.sort(array);
-
-        /* check array is sorted or not */
-        for (int i = 0; i < array.length - 1; ++i) {
-            assert (array[i].compareTo(array[i + 1]) <= 0);
-        }
-    }
-
-    /**
-     * @param unsorted - an array should be sorted
-     * @return sorted array
-     */
-    @Override
-    public <T extends Comparable<T>> T[] sort(T[] unsorted) {
-        bubbleSort(unsorted, unsorted.length);
-        return unsorted;
-    }
-
-    /**
-     * BubbleSort algorithm implements using recursion
-     *
-     * @param unsorted array contains elements
-     * @param len length of given array
-     */
-    private static <T extends Comparable<T>> void bubbleSort(T[] unsorted, int len) {
-        boolean swapped = false;
-        /* flag to check if array is sorted or not */
-        for (int i = 0; i < len - 1; ++i) {
-            if (SortUtils.greater(unsorted[i], unsorted[i + 1])) {
-                SortUtils.swap(unsorted, i, i + 1);
-                swapped = true;
-            }
-        }
-        if (swapped) {
-            bubbleSort(unsorted, len - 1);
-        }
-    }
-}
diff --git a/src/main/java/com/thealgorithms/sorts/BubbleSortRecursive.java b/src/main/java/com/thealgorithms/sorts/BubbleSortRecursive.java
new file mode 100644
index 000000000000..d9cc00f95b69
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/BubbleSortRecursive.java
@@ -0,0 +1,35 @@
+package com.thealgorithms.sorts;
+
+/**
+ * BubbleSort algorithm implemented using recursion
+ */
+public class BubbleSortRecursive implements SortAlgorithm {
+    /**
+     * @param array - an array should be sorted
+     * @return sorted array
+     */
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        bubbleSort(array, array.length);
+        return array;
+    }
+
+    /**
+     * BubbleSort algorithm implements using recursion
+     *
+     * @param array array contains elements
+     * @param len length of given array
+     */
+    private static <T extends Comparable<T>> void bubbleSort(T[] array, int len) {
+        boolean swapped = false;
+        for (int i = 0; i < len - 1; ++i) {
+            if (SortUtils.greater(array[i], array[i + 1])) {
+                SortUtils.swap(array, i, i + 1);
+                swapped = true;
+            }
+        }
+        if (swapped) {
+            bubbleSort(array, len - 1);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/BubbleSortRecursiveTest.java b/src/test/java/com/thealgorithms/sorts/BubbleSortRecursiveTest.java
new file mode 100644
index 000000000000..e05842f46be8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/BubbleSortRecursiveTest.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.sorts;
+
+public class BubbleSortRecursiveTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new BubbleSortRecursive();
+    }
+}

From ac31fba37affc343fca243771d12eeec3628bc37 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 1 Jul 2024 23:26:15 +0300
Subject: [PATCH 0231/1338] refactor: cleanup BeadSort (#5269)

* cleanup: BeadSort and BeadSortTest, adding javadocs

* checkstyle: fix formatting

* checkstyle: fix import order

* cleanup: improving code readability

* cleanup: improving code readability using enum to represent beads

* checkstyle: fix enum formatting

* fix: enum should be compared using ==, according to maven bugs finder plugin

---------

Co-authored-by: Alex Klymenko <alx@alx.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../com/thealgorithms/sorts/BeadSort.java     | 63 ++++++++++++-------
 .../com/thealgorithms/sorts/BeadSortTest.java | 43 +++++--------
 2 files changed, 56 insertions(+), 50 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/BeadSort.java b/src/main/java/com/thealgorithms/sorts/BeadSort.java
index 101a5c50af6d..1e1c64905e46 100644
--- a/src/main/java/com/thealgorithms/sorts/BeadSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BeadSort.java
@@ -1,40 +1,59 @@
 package com.thealgorithms.sorts;
 
-// BeadSort Algorithm(wikipedia) : https://en.wikipedia.org/wiki/Bead_sort
-// BeadSort can't sort negative number, Character, String. It can sort positive number only
+import java.util.Arrays;
 
 public class BeadSort {
-    public int[] sort(int[] unsorted) {
-        int[] sorted = new int[unsorted.length];
-        int max = 0;
-        for (int i = 0; i < unsorted.length; i++) {
-            max = Math.max(max, unsorted[i]);
-        }
+    private enum BeadState { BEAD, EMPTY }
 
-        char[][] grid = new char[unsorted.length][max];
-        int[] count = new int[max];
+    /**
+     * Sorts the given array using the BeadSort algorithm.
+     *
+     * @param array The array of non-negative integers to be sorted.
+     * @return The sorted array.
+     * @throws IllegalArgumentException If the array contains negative numbers.
+     */
+    public int[] sort(int[] array) {
+        allInputsMustBeNonNegative(array);
+        return extractSortedFromGrid(fillGrid(array));
+    }
 
-        for (int i = 0; i < unsorted.length; i++) {
-            for (int j = 0; j < max; j++) {
-                grid[i][j] = '-';
-            }
+    private void allInputsMustBeNonNegative(final int[] array) {
+        if (Arrays.stream(array).anyMatch(s -> s < 0)) {
+            throw new IllegalArgumentException("BeadSort cannot sort negative numbers.");
         }
+    }
 
-        for (int i = 0; i < max; i++) {
-            count[i] = 0;
-        }
+    private BeadState[][] fillGrid(final int[] array) {
+        final var maxValue = Arrays.stream(array).max().orElse(0);
+        var grid = getEmptyGrid(array.length, maxValue);
 
-        for (int i = 0; i < unsorted.length; i++) {
+        int[] count = new int[maxValue];
+        for (int i = 0, arrayLength = array.length; i < arrayLength; i++) {
             int k = 0;
-            for (int j = 0; j < unsorted[i]; j++) {
-                grid[count[max - k - 1]++][k] = '*';
+            for (int j = 0; j < array[i]; j++) {
+                grid[count[maxValue - k - 1]++][k] = BeadState.BEAD;
                 k++;
             }
         }
+        return grid;
+    }
+
+    private BeadState[][] getEmptyGrid(final int arrayLength, final int maxValue) {
+        BeadState[][] grid = new BeadState[arrayLength][maxValue];
+        for (int i = 0; i < arrayLength; i++) {
+            for (int j = 0; j < maxValue; j++) {
+                grid[i][j] = BeadState.EMPTY;
+            }
+        }
+
+        return grid;
+    }
 
-        for (int i = 0; i < unsorted.length; i++) {
+    private int[] extractSortedFromGrid(final BeadState[][] grid) {
+        int[] sorted = new int[grid.length];
+        for (int i = 0; i < grid.length; i++) {
             int k = 0;
-            for (int j = 0; j < max && grid[unsorted.length - 1 - i][j] == '*'; j++) {
+            for (int j = 0; j < grid[grid.length - 1 - i].length && grid[grid.length - 1 - i][j] == BeadState.BEAD; j++) {
                 k++;
             }
             sorted[i] = k;
diff --git a/src/test/java/com/thealgorithms/sorts/BeadSortTest.java b/src/test/java/com/thealgorithms/sorts/BeadSortTest.java
index 2ab60b205cd5..d8519147bc2e 100644
--- a/src/test/java/com/thealgorithms/sorts/BeadSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/BeadSortTest.java
@@ -1,42 +1,29 @@
 package com.thealgorithms.sorts;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class BeadSortTest {
-    // BeadSort can't sort negative number, Character, String. It can sort positive number only
-    private BeadSort beadSort = new BeadSort();
-
-    @Test
-    public void beadSortEmptyArray() {
-        int[] inputArray = {};
-        int[] outputArray = beadSort.sort(inputArray);
-        int[] expectedOutput = {};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void beadSortSingleIntegerArray() {
-        int[] inputArray = {4};
-        int[] outputArray = beadSort.sort(inputArray);
-        int[] expectedOutput = {4};
-        assertArrayEquals(outputArray, expectedOutput);
+    @ParameterizedTest
+    @MethodSource("provideArraysForBeadSort")
+    public void testBeadSort(int[] inputArray, int[] expectedArray) {
+        BeadSort beadSort = new BeadSort();
+        assertArrayEquals(expectedArray, beadSort.sort(inputArray));
     }
 
-    @Test
-    public void bogoSortNonDuplicateIntegerArray() {
-        int[] inputArray = {6, 1, 99, 27, 15, 23, 36};
-        int[] outputArray = beadSort.sort(inputArray);
-        int[] expectedOutput = {1, 6, 15, 23, 27, 36, 99};
-        assertArrayEquals(outputArray, expectedOutput);
+    private static Stream<Arguments> provideArraysForBeadSort() {
+        return Stream.of(Arguments.of(new int[] {}, new int[] {}), Arguments.of(new int[] {4}, new int[] {4}), Arguments.of(new int[] {6, 1, 99, 27, 15, 23, 36}, new int[] {1, 6, 15, 23, 27, 36, 99}), Arguments.of(new int[] {6, 1, 27, 15, 23, 27, 36, 23}, new int[] {1, 6, 15, 23, 23, 27, 27, 36}),
+            Arguments.of(new int[] {5, 5, 5, 5, 5}, new int[] {5, 5, 5, 5, 5}), Arguments.of(new int[] {1, 2, 3, 4, 5}, new int[] {1, 2, 3, 4, 5}), Arguments.of(new int[] {5, 4, 3, 2, 1}, new int[] {1, 2, 3, 4, 5}));
     }
 
     @Test
-    public void bogoSortDuplicateIntegerArray() {
-        int[] inputArray = {6, 1, 27, 15, 23, 27, 36, 23};
-        int[] outputArray = beadSort.sort(inputArray);
-        int[] expectedOutput = {1, 6, 15, 23, 23, 27, 27, 36};
-        assertArrayEquals(outputArray, expectedOutput);
+    public void testWithNegativeNumbers() {
+        assertThrows(IllegalArgumentException.class, () -> new BeadSort().sort(new int[] {3, 1, 4, 1, 5, -9}));
     }
 }

From e63c39ac88187b15576f43ee8ebb2d832c0d5ae3 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 2 Jul 2024 08:55:03 +0200
Subject: [PATCH 0232/1338] Chore(deps): bump gitpod/workspace-java-21 from
 2024-06-24-08-46-07 to 2024-06-26-08-49-45 (#5272)

Chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2024-06-24-08-46-07 to 2024-06-26-08-49-45.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 31b013937b4e..8dcf7e6afc4a 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-06-24-08-46-07
+FROM gitpod/workspace-java-21:2024-06-26-08-49-45
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 5bc96cf78955dc9c2c89a1e39ccbbb15a6b04e08 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 2 Jul 2024 21:47:35 +0200
Subject: [PATCH 0233/1338] style: include `RV_ABSOLUTE_VALUE_OF_HASHCODE`
 (#5273)

---
 spotbugs-exclude.xml                                           | 3 ---
 .../hashmap/hashing/GenericHashMapUsingArray.java              | 3 +--
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index f1b48d52829b..8648b9109013 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -89,9 +89,6 @@
     <Match>
         <Bug pattern="RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE" />
     </Match>
-    <Match>
-        <Bug pattern="RV_ABSOLUTE_VALUE_OF_HASHCODE" />
-    </Match>
     <!-- fb-contrib -->
     <Match>
         <Bug pattern="OCP_OVERLY_CONCRETE_PARAMETER" />
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
index 9fbb2ff0ad62..416cee99d028 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
@@ -47,8 +47,7 @@ public void put(K key, V value) {
 
     // tells which bucket to go to
     private int hashFunction(K key) {
-        int hc = key.hashCode();
-        return Math.abs(hc) % buckets.length;
+        return Math.floorMod(key.hashCode(), buckets.length);
     }
 
     private void reHash() {

From 26b4b82949ae2afb4e2aab94a2c96ee07acff5aa Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 3 Jul 2024 18:55:09 +0200
Subject: [PATCH 0234/1338] style: include
 `OI_OPTIONAL_ISSUES_USES_IMMEDIATE_EXECUTION` (#5274)

---
 spotbugs-exclude.xml                                          | 3 ---
 .../com/thealgorithms/searches/BreadthFirstSearchTest.java    | 4 ++--
 .../java/com/thealgorithms/searches/DepthFirstSearchTest.java | 4 ++--
 3 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 8648b9109013..9aa2e50fbd05 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -123,9 +123,6 @@
     <Match>
         <Bug pattern="BL_BURYING_LOGIC" />
     </Match>
-    <Match>
-        <Bug pattern="OI_OPTIONAL_ISSUES_USES_IMMEDIATE_EXECUTION" />
-    </Match>
     <Match>
         <Bug pattern="PCOA_PARTIALLY_CONSTRUCTED_OBJECT_ACCESS" />
     </Match>
diff --git a/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java b/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java
index 2a32a4ddb46c..d05856dd29ad 100644
--- a/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java
@@ -53,7 +53,7 @@ public void testSearchRoot() {
 
         // check value
         Optional<Node<String>> value = bfs.search(root, expectedValue);
-        assertEquals(expectedValue, value.orElse(new Node<>("")).getValue());
+        assertEquals(expectedValue, value.orElseGet(() -> new Node<>("")).getValue());
 
         // check path
         assertArrayEquals(expectedPath.toArray(), bfs.getVisited().toArray());
@@ -65,7 +65,7 @@ public void testSearchF() {
         List<String> expectedPath = List.of("A", "B", "C", "D", "E", "F");
 
         // check value
-        Optional<Node<String>> value = Optional.of(bfs.search(root, expectedValue).orElse(new Node<>(null)));
+        Optional<Node<String>> value = Optional.of(bfs.search(root, expectedValue).orElseGet(() -> new Node<>(null)));
         assertEquals(expectedValue, value.get().getValue());
 
         // check path
diff --git a/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java b/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java
index af21b570fd7c..2785d48b70cf 100644
--- a/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java
@@ -54,7 +54,7 @@ public void testSearchRoot() {
 
         // check value
         Optional<Node<Integer>> value = dfs.recursiveSearch(root, expectedValue);
-        assertEquals(expectedValue, value.orElse(new Node<>(null)).getValue());
+        assertEquals(expectedValue, value.orElseGet(() -> new Node<>(null)).getValue());
 
         // check path
         assertArrayEquals(expectedPath.toArray(), dfs.getVisited().toArray());
@@ -67,7 +67,7 @@ public void testSearch4() {
 
         // check value
         Optional<Node<Integer>> value = dfs.recursiveSearch(root, expectedValue);
-        assertEquals(expectedValue, value.orElse(new Node<>(null)).getValue());
+        assertEquals(expectedValue, value.orElseGet(() -> new Node<>(null)).getValue());
 
         // check path
         assertArrayEquals(expectedPath.toArray(), dfs.getVisited().toArray());

From 96e59e063a3819389d94320fe1c8d5c915e0634b Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 5 Jul 2024 21:52:54 +0200
Subject: [PATCH 0235/1338] style: include `DLS_DEAD_LOCAL_STORE` (#5276)

---
 spotbugs-exclude.xml                                    | 3 ---
 src/main/java/com/thealgorithms/maths/Gaussian.java     | 4 +---
 src/test/java/com/thealgorithms/maths/GaussianTest.java | 4 +---
 3 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 9aa2e50fbd05..38d65b7ff507 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -65,9 +65,6 @@
     <Match>
         <Bug pattern="UWF_UNWRITTEN_FIELD" />
     </Match>
-    <Match>
-        <Bug pattern="DLS_DEAD_LOCAL_STORE" />
-    </Match>
     <Match>
         <Bug pattern="UWF_NULL_FIELD" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/maths/Gaussian.java b/src/main/java/com/thealgorithms/maths/Gaussian.java
index cefbaea5b9b4..255a84d13854 100644
--- a/src/main/java/com/thealgorithms/maths/Gaussian.java
+++ b/src/main/java/com/thealgorithms/maths/Gaussian.java
@@ -7,7 +7,6 @@ private Gaussian() {
     }
 
     public static ArrayList<Double> gaussian(int matSize, ArrayList<Double> matrix) {
-        ArrayList<Double> answerArray = new ArrayList<Double>();
         int i;
         int j = 0;
 
@@ -22,8 +21,7 @@ public static ArrayList<Double> gaussian(int matSize, ArrayList<Double> matrix)
         }
 
         mat = gaussianElimination(matSize, i, mat);
-        answerArray = valueOfGaussian(matSize, x, mat);
-        return answerArray;
+        return valueOfGaussian(matSize, x, mat);
     }
 
     // Perform Gaussian elimination
diff --git a/src/test/java/com/thealgorithms/maths/GaussianTest.java b/src/test/java/com/thealgorithms/maths/GaussianTest.java
index 16b8da1338e7..fe900fa22d26 100644
--- a/src/test/java/com/thealgorithms/maths/GaussianTest.java
+++ b/src/test/java/com/thealgorithms/maths/GaussianTest.java
@@ -12,7 +12,6 @@ public class GaussianTest {
     @Test
     void passTest1() {
         ArrayList<Double> list = new ArrayList<Double>();
-        ArrayList<Double> gaussian = new ArrayList<Double>();
         ArrayList<Double> answer = new ArrayList<Double>();
         answer.add(0.0);
         answer.add(1.0);
@@ -24,8 +23,7 @@ void passTest1() {
         list.add(2.0);
         list.add(1.0);
         list.add(1.0);
-        gaussian = gaussian(matrixSize, list);
 
-        assertEquals(answer, gaussian);
+        assertEquals(answer, gaussian(matrixSize, list));
     }
 }

From 6b41c7d7a01fff88a21536f33544ccd600864b23 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 9 Jul 2024 09:01:00 +0200
Subject: [PATCH 0236/1338] Chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.8.6.1 to 4.8.6.2 (#5278)

Chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.8.6.1 to 4.8.6.2.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.8.6.1...spotbugs-maven-plugin-4.8.6.2)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 924a736d526d..ce3bcd28c4f4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.8.6.1</version>
+                <version>4.8.6.2</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 14264602de0ee63c412842b771f60346d9c108b4 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 9 Jul 2024 09:09:03 +0200
Subject: [PATCH 0237/1338] Chore(deps): bump gitpod/workspace-java-21 from
 2024-06-26-08-49-45 to 2024-07-02-14-18-47 (#5279)

Chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2024-06-26-08-49-45 to 2024-07-02-14-18-47.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 8dcf7e6afc4a..99a25f592e0a 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-06-26-08-49-45
+FROM gitpod/workspace-java-21:2024-07-02-14-18-47
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 57f65808ad5445f5bd09eb00e58555067655f721 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 9 Jul 2024 22:44:42 +0200
Subject: [PATCH 0238/1338] refactor: `MergeSortNoExtraSpace` (#5277)

* refactor: MergeSortNoExtraSpace, change naming, adding test

* checkstyle: fix import ordering, and formatting

* fix: adding negative numbers check, fix possible overflow

* checkstyle: remove newline

---------

Co-authored-by: Alex Klymenko <alx@alx.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 .../sorts/MergeSortNoExtraSpace.java          | 91 +++++++++++--------
 .../sorts/MergeSortNoExtraSpaceTest.java      | 34 +++++++
 2 files changed, 87 insertions(+), 38 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/sorts/MergeSortNoExtraSpaceTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java b/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
index 290c2df59c3d..7aa3b56e068c 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java
@@ -1,73 +1,88 @@
 package com.thealgorithms.sorts;
 
 import java.util.Arrays;
-import java.util.Scanner;
 
-/*This code implements the mergeSort algorithm without extra space
-For understanding about mergesort visit :https://www.geeksforgeeks.org/merge-sort/
+/**
+ * Implementation of Merge Sort without using extra space for merging.
+ * This implementation performs in-place merging to sort the array of integers.
  */
 public final class MergeSortNoExtraSpace {
     private MergeSortNoExtraSpace() {
     }
 
-    public static void callMergeSort(int[] a, int n) {
-        int maxele = Arrays.stream(a).max().getAsInt() + 1;
-        mergeSort(a, 0, n - 1, maxele);
+    /**
+     * Sorts the array using in-place merge sort algorithm.
+     *
+     * @param array the array to be sorted
+     * @return the sorted array
+     * @throws IllegalArgumentException If the array contains negative numbers.
+     */
+    public static int[] sort(int[] array) {
+        if (array.length == 0) {
+            return array;
+        }
+        if (Arrays.stream(array).anyMatch(s -> s < 0)) {
+            throw new IllegalArgumentException("Implementation cannot sort negative numbers.");
+        }
+
+        final int maxElement = Arrays.stream(array).max().getAsInt() + 1;
+        mergeSort(array, 0, array.length - 1, maxElement);
+        return array;
     }
 
-    public static void mergeSort(int[] a, int start, int end, int maxele) { // this function divides the array into 2 halves
+    /**
+     * Recursively divides the array into two halves, sorts and merges them.
+     *
+     * @param array  the array to be sorted
+     * @param start  the starting index of the array
+     * @param end    the ending index of the array
+     * @param maxElement the value greater than any element in the array, used for encoding
+     */
+    public static void mergeSort(int[] array, int start, int end, int maxElement) {
         if (start < end) {
-            int mid = (start + end) / 2;
-            mergeSort(a, start, mid, maxele);
-            mergeSort(a, mid + 1, end, maxele);
-            implementMergeSort(a, start, mid, end, maxele);
+            final int middle = (start + end) >>> 1;
+            mergeSort(array, start, middle, maxElement);
+            mergeSort(array, middle + 1, end, maxElement);
+            merge(array, start, middle, end, maxElement);
         }
     }
 
-    public static void implementMergeSort(int[] a, int start, int mid, int end,
-        int maxele) { // implementation of mergesort
+    /**
+     * Merges two sorted subarrays [start...middle] and [middle+1...end] in place.
+     *
+     * @param array  the array containing the subarrays to be merged
+     * @param start  the starting index of the first subarray
+     * @param middle    the ending index of the first subarray and starting index of the second subarray
+     * @param end    the ending index of the second subarray
+     * @param maxElement the value greater than any element in the array, used for encoding
+     */
+    private static void merge(int[] array, int start, int middle, int end, int maxElement) {
         int i = start;
-        int j = mid + 1;
+        int j = middle + 1;
         int k = start;
-        while (i <= mid && j <= end) {
-            if (a[i] % maxele <= a[j] % maxele) {
-                a[k] = a[k] + (a[i] % maxele) * maxele;
+        while (i <= middle && j <= end) {
+            if (array[i] % maxElement <= array[j] % maxElement) {
+                array[k] = array[k] + (array[i] % maxElement) * maxElement;
                 k++;
                 i++;
             } else {
-                a[k] = a[k] + (a[j] % maxele) * maxele;
+                array[k] = array[k] + (array[j] % maxElement) * maxElement;
                 k++;
                 j++;
             }
         }
-        while (i <= mid) {
-            a[k] = a[k] + (a[i] % maxele) * maxele;
+        while (i <= middle) {
+            array[k] = array[k] + (array[i] % maxElement) * maxElement;
             k++;
             i++;
         }
         while (j <= end) {
-            a[k] = a[k] + (a[j] % maxele) * maxele;
+            array[k] = array[k] + (array[j] % maxElement) * maxElement;
             k++;
             j++;
         }
         for (i = start; i <= end; i++) {
-            a[i] = a[i] / maxele;
-        }
-    }
-
-    public static void main(String[] args) {
-        Scanner inp = new Scanner(System.in);
-        System.out.println("Enter array size");
-        int n = inp.nextInt();
-        int[] a = new int[n];
-        System.out.println("Enter array elements");
-        for (int i = 0; i < n; i++) {
-            a[i] = inp.nextInt();
-        }
-        callMergeSort(a, n);
-        for (int i = 0; i < a.length; i++) {
-            System.out.print(a[i] + " ");
+            array[i] = array[i] / maxElement;
         }
-        inp.close();
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/MergeSortNoExtraSpaceTest.java b/src/test/java/com/thealgorithms/sorts/MergeSortNoExtraSpaceTest.java
new file mode 100644
index 000000000000..5677a7c95e09
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/MergeSortNoExtraSpaceTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class MergeSortNoExtraSpaceTest {
+    record TestCase(int[] inputArray, int[] expectedArray) {
+    }
+
+    static Stream<TestCase> provideTestCases() {
+        return Stream.of(new TestCase(new int[] {}, new int[] {}), new TestCase(new int[] {1}, new int[] {1}), new TestCase(new int[] {1, 2, 3, 4, 5}, new int[] {1, 2, 3, 4, 5}), new TestCase(new int[] {5, 4, 3, 2, 1}, new int[] {1, 2, 3, 4, 5}),
+            new TestCase(new int[] {3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5}, new int[] {1, 1, 2, 3, 3, 4, 5, 5, 5, 6, 9}), new TestCase(new int[] {4, 2, 4, 3, 2, 1, 5}, new int[] {1, 2, 2, 3, 4, 4, 5}), new TestCase(new int[] {0, 0, 0, 0}, new int[] {0, 0, 0, 0}),
+            new TestCase(new int[] {1000, 500, 100, 50, 10, 5, 1}, new int[] {1, 5, 10, 50, 100, 500, 1000}), new TestCase(new int[] {1, 2, 3, 1, 2, 3, 1, 2, 3}, new int[] {1, 1, 1, 2, 2, 2, 3, 3, 3}),
+            new TestCase(new int[] {10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0}, new int[] {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}), new TestCase(new int[] {2, 1}, new int[] {1, 2}), new TestCase(new int[] {1, 3, 2}, new int[] {1, 2, 3}));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testCountingSort(TestCase testCase) {
+        int[] outputArray = MergeSortNoExtraSpace.sort(testCase.inputArray);
+        assertArrayEquals(testCase.expectedArray, outputArray);
+    }
+
+    @Test
+    public void testNegativeNumbers() {
+        int[] arrayWithNegatives = {1, -2, 3, -4};
+        assertThrows(IllegalArgumentException.class, () -> MergeSortNoExtraSpace.sort(arrayWithNegatives));
+    }
+}

From 06927d3fda859f29462c8aeff2b538d5d1f7218b Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 10 Jul 2024 09:00:01 +0200
Subject: [PATCH 0239/1338] Chore(deps-dev): bump org.assertj:assertj-core from
 3.26.0 to 3.26.3 (#5281)

Bumps [org.assertj:assertj-core](https://github.com/assertj/assertj) from 3.26.0 to 3.26.3.
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](https://github.com/assertj/assertj/compare/assertj-build-3.26.0...assertj-build-3.26.3)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index ce3bcd28c4f4..75e57d96c84d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.26.0</assertj.version>
+        <assertj.version>3.26.3</assertj.version>
     </properties>
 
     <dependencyManagement>

From f83bb659ba54f0133040c0c4c1b74955c6e8e830 Mon Sep 17 00:00:00 2001
From: yuvashreenarayanan3
 <85839447+yuvashreenarayanan3@users.noreply.github.com>
Date: Wed, 10 Jul 2024 22:50:32 +0530
Subject: [PATCH 0240/1338] refactor: redesign `ArrayCombination` (#5181)

* Related to #5164 (Redesign of ArrayCombination)

* Checkstyle fix

* Clang_format

* refactor: cleanup

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Co-authored-by: vil02 <vil02@o2.pl>
---
 .../backtracking/ArrayCombination.java        | 42 ++++++++------
 .../backtracking/ArrayCombinationTest.java    | 57 +++++++------------
 2 files changed, 47 insertions(+), 52 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
index a0b886e6be8a..a064decc0eb7 100644
--- a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
+++ b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
@@ -1,32 +1,42 @@
 package com.thealgorithms.backtracking;
 
+import java.util.ArrayList;
 import java.util.List;
-import java.util.TreeSet;
 
 /**
- * Finds all permutations of 1...n of length k
- * @author TheClerici (<a href="https://github.com/TheClerici">git-TheClerici</a>)
+ * Finds all combinations of 0...n-1 of length k
  */
 public final class ArrayCombination {
     private ArrayCombination() {
     }
-    private static int length;
 
     /**
-     * Find all combinations of 1..n by creating an array and using backtracking in Combination.java
-     * @param n max value of the array.
-     * @param k length of combination
-     * @return a list of all combinations of length k. If k == 0, return null.
+     * Finds all combinations of length k of 0..n-1 using backtracking.
+     *
+     * @param n Number of the elements.
+     * @param k Length of the combination.
+     * @return A list of all combinations of length k.
      */
-    public static List<TreeSet<Integer>> combination(int n, int k) {
-        if (n <= 0) {
-            return null;
+    public static List<List<Integer>> combination(int n, int k) {
+        if (n < 0 || k < 0 || k > n) {
+            throw new IllegalArgumentException("Wrong input.");
         }
-        length = k;
-        Integer[] arr = new Integer[n];
-        for (int i = 1; i <= n; i++) {
-            arr[i - 1] = i;
+
+        List<List<Integer>> combinations = new ArrayList<>();
+        combine(combinations, new ArrayList<>(), 0, n, k);
+        return combinations;
+    }
+
+    private static void combine(List<List<Integer>> combinations, List<Integer> current, int start, int n, int k) {
+        if (current.size() == k) { // Base case: combination found
+            combinations.add(new ArrayList<>(current)); // Copy to avoid modification
+            return;
+        }
+
+        for (int i = start; i < n; i++) {
+            current.add(i);
+            combine(combinations, current, i + 1, n, k);
+            current.removeLast(); // Backtrack
         }
-        return Combination.combination(arr, length);
     }
 }
diff --git a/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java b/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java
index 23fa5d54574c..a4ff7fe892d5 100644
--- a/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java
@@ -1,51 +1,36 @@
 package com.thealgorithms.backtracking;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import com.thealgorithms.maths.BinomialCoefficient;
+import java.util.ArrayList;
 import java.util.List;
-import java.util.TreeSet;
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class ArrayCombinationTest {
-
-    @Test
-    void testNBeingZeroOrLess() {
-        List<TreeSet<Integer>> zeroResult = ArrayCombination.combination(0, 1);
-        List<TreeSet<Integer>> negativeResult = ArrayCombination.combination(-1, 1);
-        assertNull(zeroResult);
-        assertNull(negativeResult);
-    }
-
-    @Test
-    void testNoLengthElement() {
-        List<TreeSet<Integer>> result = ArrayCombination.combination(2, 0);
-        assertNull(result);
+    @ParameterizedTest
+    @MethodSource("regularInputs")
+    void testCombination(int n, int k, List<List<Integer>> expected) {
+        assertEquals(expected.size(), BinomialCoefficient.binomialCoefficient(n, k));
+        assertEquals(expected, ArrayCombination.combination(n, k));
     }
 
-    @Test
-    void testLengthOne() {
-        List<TreeSet<Integer>> result = ArrayCombination.combination(2, 1);
-        assert result != null;
-        assertEquals(1, result.get(0).iterator().next());
-        assertEquals(2, result.get(1).iterator().next());
+    @ParameterizedTest
+    @MethodSource("wrongInputs")
+    void testCombinationThrows(int n, int k) {
+        assertThrows(IllegalArgumentException.class, () -> ArrayCombination.combination(n, k));
     }
 
-    @Test
-    void testLengthTwo() {
-        List<TreeSet<Integer>> result = ArrayCombination.combination(2, 2);
-        assert result != null;
-        Integer[] arr = result.get(0).toArray(new Integer[2]);
-        assertEquals(1, arr[0]);
-        assertEquals(2, arr[1]);
+    private static Stream<Arguments> regularInputs() {
+        return Stream.of(Arguments.of(0, 0, List.of(new ArrayList<Integer>())), Arguments.of(1, 0, List.of(new ArrayList<Integer>())), Arguments.of(1, 1, List.of(List.of(0))), Arguments.of(3, 0, List.of(new ArrayList<Integer>())), Arguments.of(3, 1, List.of(List.of(0), List.of(1), List.of(2))),
+            Arguments.of(4, 2, List.of(List.of(0, 1), List.of(0, 2), List.of(0, 3), List.of(1, 2), List.of(1, 3), List.of(2, 3))));
     }
 
-    @Test
-    void testLengthFive() {
-        List<TreeSet<Integer>> result = ArrayCombination.combination(10, 5);
-        assert result != null;
-        Integer[] arr = result.get(0).toArray(new Integer[5]);
-        assertEquals(1, arr[0]);
-        assertEquals(5, arr[4]);
+    private static Stream<Arguments> wrongInputs() {
+        return Stream.of(Arguments.of(-1, 0), Arguments.of(0, -1), Arguments.of(2, 100));
     }
 }

From 8ea90fdd428d281d85da1c656f75fca04f27df86 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 11 Jul 2024 08:41:44 +0200
Subject: [PATCH 0241/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-surefire-plugin from 3.3.0 to 3.3.1 (#5282)

Chore(deps): bump org.apache.maven.plugins:maven-surefire-plugin

Bumps [org.apache.maven.plugins:maven-surefire-plugin](https://github.com/apache/maven-surefire) from 3.3.0 to 3.3.1.
- [Release notes](https://github.com/apache/maven-surefire/releases)
- [Commits](https://github.com/apache/maven-surefire/compare/surefire-3.3.0...surefire-3.3.1)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-surefire-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 75e57d96c84d..7e363fcf258a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -63,7 +63,7 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.3.0</version>
+                <version>3.3.1</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>

From 87e6184494b40900a9e1b31c66032840ab373dbc Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 12 Jul 2024 08:49:11 +0200
Subject: [PATCH 0242/1338] cleanup: removing wrong `CountingSort`
 implementation (#5284)

cleanup: removing CountingSort

Co-authored-by: Alex Klymenko <alx@alx.com>
---
 DIRECTORY.md                                  |  1 -
 .../com/thealgorithms/sorts/CountingSort.java | 93 -------------------
 2 files changed, 94 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/sorts/CountingSort.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6cecfef02de5..2b1f43965304 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -495,7 +495,6 @@
             * [CircleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CircleSort.java)
             * [CocktailShakerSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java)
             * [CombSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CombSort.java)
-            * [CountingSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CountingSort.java)
             * [CycleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CycleSort.java)
             * [DNFSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DNFSort.java)
             * [DualPivotQuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java)
diff --git a/src/main/java/com/thealgorithms/sorts/CountingSort.java b/src/main/java/com/thealgorithms/sorts/CountingSort.java
deleted file mode 100644
index e83271d9ee67..000000000000
--- a/src/main/java/com/thealgorithms/sorts/CountingSort.java
+++ /dev/null
@@ -1,93 +0,0 @@
-package com.thealgorithms.sorts;
-
-import static com.thealgorithms.sorts.SortUtils.print;
-import static java.util.stream.Collectors.toList;
-import static java.util.stream.Collectors.toMap;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-import java.util.Map;
-import java.util.TreeMap;
-import java.util.stream.IntStream;
-import java.util.stream.Stream;
-
-/**
- * @author Youssef Ali (https://github.com/youssefAli11997)
- * @author Podshivalov Nikita (https://github.com/nikitap492)
- */
-class CountingSort implements SortAlgorithm {
-
-    @Override
-    public <T extends Comparable<T>> T[] sort(T[] unsorted) {
-        return sort(Arrays.asList(unsorted)).toArray(unsorted);
-    }
-
-    /**
-     * This method implements the Generic Counting Sort
-     *
-     * @param list The list to be sorted
-     * <p>
-     * Sorts the list in increasing order The method uses list elements as keys
-     * in the frequency map
-     */
-    @Override
-    public <T extends Comparable<T>> List<T> sort(List<T> list) {
-        Map<T, Integer> frequency = new TreeMap<>();
-        // The final output array
-        List<T> sortedArray = new ArrayList<>(list.size());
-
-        // Counting the frequency of @param array elements
-        list.forEach(v -> frequency.put(v, frequency.getOrDefault(v, 0) + 1));
-
-        // Filling the sortedArray
-        for (Map.Entry<T, Integer> element : frequency.entrySet()) {
-            for (int j = 0; j < element.getValue(); j++) {
-                sortedArray.add(element.getKey());
-            }
-        }
-
-        return sortedArray;
-    }
-
-    /**
-     * Stream Counting Sort The same as method {@link CountingSort#sort(List)} }
-     * but this method uses stream API
-     *
-     * @param list The list to be sorted
-     */
-    private static <T extends Comparable<T>> List<T> streamSort(List<T> list) {
-        return list.stream().collect(toMap(k -> k, v -> 1, (v1, v2) -> v1 + v2, TreeMap::new)).entrySet().stream().flatMap(entry -> IntStream.rangeClosed(1, entry.getValue()).mapToObj(t -> entry.getKey())).collect(toList());
-    }
-
-    // Driver Program
-    public static void main(String[] args) {
-        // Integer Input
-        List<Integer> unsortedInts = Stream.of(4, 23, 6, 78, 1, 54, 23, 1, 9, 231, 9, 12).collect(toList());
-        CountingSort countingSort = new CountingSort();
-
-        System.out.println("Before Sorting:");
-        print(unsortedInts);
-
-        // Output => 1 1 4 6 9 9 12 23 23 54 78 231
-        System.out.println("After Sorting:");
-        print(countingSort.sort(unsortedInts));
-        System.out.println("After Sorting By Streams:");
-        print(streamSort(unsortedInts));
-
-        System.out.println("\n------------------------------\n");
-
-        // String Input
-        List<String> unsortedStrings = Stream.of("c", "a", "e", "b", "d", "a", "f", "g", "c").collect(toList());
-
-        System.out.println("Before Sorting:");
-        print(unsortedStrings);
-
-        // Output => a a b c c d e f g
-        System.out.println("After Sorting:");
-        print(countingSort.sort(unsortedStrings));
-
-        System.out.println("After Sorting By Streams:");
-        print(streamSort(unsortedStrings));
-    }
-}

From 2d6c39ce100855c87b41f0c3594586ba7fdd6fce Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 12 Jul 2024 20:03:54 +0200
Subject: [PATCH 0243/1338] feat: `CountingSort` implementation (#5287)

* feat: CountingSort

* checkstyle: fix formatting

* refactor: adding additional final modifiers

* refactor: restructure sorting, update docs and tests

* docs: typo fix

---------

Co-authored-by: Alex Klymenko <alx@alx.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 DIRECTORY.md                                  |  2 +
 .../com/thealgorithms/sorts/CountingSort.java | 60 +++++++++++++++++++
 .../thealgorithms/sorts/CountingSortTest.java | 27 +++++++++
 3 files changed, 89 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/CountingSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/CountingSortTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 2b1f43965304..aa1005027066 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -494,6 +494,7 @@
             * [BucketSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BucketSort.java)
             * [CircleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CircleSort.java)
             * [CocktailShakerSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java)
+            * [CountingSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CountingSort.java)
             * [CombSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CombSort.java)
             * [CycleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CycleSort.java)
             * [DNFSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DNFSort.java)
@@ -862,6 +863,7 @@
             * [BucketSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BucketSortTest.java)
             * [CircleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CircleSortTest.java)
             * [CocktailShakerSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java)
+            * [CountingSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CountingSortTest.java)
             * [CombSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CombSortTest.java)
             * [DualPivotQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java)
             * [DutchNationalFlagSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java)
diff --git a/src/main/java/com/thealgorithms/sorts/CountingSort.java b/src/main/java/com/thealgorithms/sorts/CountingSort.java
new file mode 100644
index 000000000000..5d54205032d4
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/CountingSort.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.sorts;
+
+import java.util.Arrays;
+
+/**
+ * A standard implementation of the Counting Sort algorithm for integer arrays.
+ * This implementation has a time complexity of O(n + k), where n is the number
+ * of elements in the input array and k is the range of the input.
+ * It works only with integer arrays.
+ *
+ * The space complexity is O(k), where k is the range of the input integers.
+ *
+ * Note: This implementation handles negative integers as it
+ * calculates the range based on the minimum and maximum values of the array.
+ *
+ */
+public final class CountingSort {
+    private CountingSort() {
+    }
+
+    /**
+     * Sorts an array of integers using the Counting Sort algorithm.
+     *
+     * @param array the array to be sorted
+     * @return the sorted array
+     */
+    public static int[] sort(int[] array) {
+        if (array.length == 0) {
+            return array;
+        }
+        final var stats = Arrays.stream(array).summaryStatistics();
+        final int min = stats.getMin();
+        int[] count = computeHistogram(array, min, stats.getMax() - min + 1);
+        toCumulative(count);
+        return reconstructSorted(count, min, array);
+    }
+
+    private static int[] computeHistogram(final int[] array, final int shift, final int spread) {
+        int[] res = new int[spread];
+        for (final var value : array) {
+            res[value - shift]++;
+        }
+        return res;
+    }
+
+    private static void toCumulative(int[] count) {
+        for (int i = 1; i < count.length; i++) {
+            count[i] += count[i - 1];
+        }
+    }
+
+    private static int[] reconstructSorted(final int[] cumulativeCount, final int shift, final int[] array) {
+        int[] res = new int[array.length];
+        for (int i = array.length - 1; i >= 0; i--) {
+            res[cumulativeCount[array[i] - shift] - 1] = array[i];
+            cumulativeCount[array[i] - shift]--;
+        }
+        return res;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/CountingSortTest.java b/src/test/java/com/thealgorithms/sorts/CountingSortTest.java
new file mode 100644
index 000000000000..2426de6f2807
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/CountingSortTest.java
@@ -0,0 +1,27 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class CountingSortTest {
+
+    record TestCase(int[] inputArray, int[] expectedArray) {
+    }
+
+    static Stream<TestCase> provideTestCases() {
+        return Stream.of(new TestCase(new int[] {}, new int[] {}), new TestCase(new int[] {4}, new int[] {4}), new TestCase(new int[] {6, 1, 99, 27, 15, 23, 36}, new int[] {1, 6, 15, 23, 27, 36, 99}), new TestCase(new int[] {6, 1, 27, 15, 23, 27, 36, 23}, new int[] {1, 6, 15, 23, 23, 27, 27, 36}),
+            new TestCase(new int[] {5, 5, 5, 5, 5}, new int[] {5, 5, 5, 5, 5}), new TestCase(new int[] {1, 2, 3, 4, 5}, new int[] {1, 2, 3, 4, 5}), new TestCase(new int[] {5, 4, 3, 2, 1}, new int[] {1, 2, 3, 4, 5}), new TestCase(new int[] {3, -1, 4, 1, 5, -9}, new int[] {-9, -1, 1, 3, 4, 5}),
+            new TestCase(new int[] {0, 0, 0, 0}, new int[] {0, 0, 0, 0}), new TestCase(new int[] {3, 3, -1, -1, 2, 2, 0, 0}, new int[] {-1, -1, 0, 0, 2, 2, 3, 3}), new TestCase(new int[] {-3, -2, -1, -5, -4}, new int[] {-5, -4, -3, -2, -1}),
+            new TestCase(new int[] {1000, 500, 100, 50, 10, 5, 1}, new int[] {1, 5, 10, 50, 100, 500, 1000}), new TestCase(new int[] {4, -5, 10, 0}, new int[] {-5, 0, 4, 10}));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testCountingSortException(TestCase testCase) {
+        int[] outputArray = CountingSort.sort(testCase.inputArray);
+        assertArrayEquals(testCase.expectedArray, outputArray);
+    }
+}

From 57878cac555eebf33a86b3d808e7b91f26174458 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 13 Jul 2024 19:14:49 +0200
Subject: [PATCH 0244/1338] refactor: cleanup `CycleSort` (#5271)

* refactor: cleanup CycleSort. Adding test for it. Simplify code

* refactor: CycleSortTest to directory file

* tests: Adding more various tests cases for testing sorting algorithms

* checkstyle: imports and whitespaces fixes

* tests: removing boolean sorting

* checkstyle: fix "eedBraces: 'if' construct must use '{}'s"

* checkstyle: reduce "Too many static imports"

---------

Co-authored-by: Alex Klymenko <alx@alx.com>
---
 DIRECTORY.md                                  |   1 +
 .../com/thealgorithms/sorts/CycleSort.java    | 121 +++++------
 .../thealgorithms/sorts/CycleSortTest.java    |   8 +
 .../sorts/SortingAlgorithmTest.java           | 191 ++++++++++++++++++
 4 files changed, 252 insertions(+), 69 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/sorts/CycleSortTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index aa1005027066..02ad74351bd7 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -865,6 +865,7 @@
             * [CocktailShakerSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java)
             * [CountingSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CountingSortTest.java)
             * [CombSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CombSortTest.java)
+            * [CycleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CycleSortTest.java)
             * [DualPivotQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java)
             * [DutchNationalFlagSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java)
             * [ExchangeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/ExchangeSortTest.java)
diff --git a/src/main/java/com/thealgorithms/sorts/CycleSort.java b/src/main/java/com/thealgorithms/sorts/CycleSort.java
index 0852abfaae24..e254dd8102d2 100644
--- a/src/main/java/com/thealgorithms/sorts/CycleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CycleSort.java
@@ -1,100 +1,83 @@
 package com.thealgorithms.sorts;
 
-import static com.thealgorithms.sorts.SortUtils.less;
-import static com.thealgorithms.sorts.SortUtils.print;
-
 /**
+ * This class implements the cycle sort algorithm.
+ * Cycle sort is an in-place sorting algorithm, unstable, and efficient for scenarios with limited memory usage.
  * @author Podshivalov Nikita (https://github.com/nikitap492)
  */
 class CycleSort implements SortAlgorithm {
-
+    /**
+     * Sorts an array of comparable elements using the cycle sort algorithm.
+     *
+     * @param array the array to be sorted
+     * @param <T> the type of elements in the array, must be comparable
+     * @return the sorted array
+     */
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] arr) {
-        int n = arr.length;
-
-        // traverse array elements
-        for (int j = 0; j <= n - 2; j++) {
-            // initialize item as starting point
-            T item = arr[j];
-
-            // Find position where we put the item.
-            int pos = j;
-            for (int i = j + 1; i < n; i++) {
-                if (less(arr[i], item)) {
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        for (int cycleStart = 0; cycleStart <= array.length - 2; cycleStart++) {
+            T item = array[cycleStart];
+
+            // Find the position where we put the element
+            int pos = cycleStart;
+            for (int i = cycleStart + 1; i < array.length; i++) {
+                if (SortUtils.less(array[i], item)) {
                     pos++;
                 }
             }
 
-            // If item is already in correct position
-            if (pos == j) {
+            // If the item is already in the correct position
+            if (pos == cycleStart) {
                 continue;
             }
 
-            // ignore all duplicate elements
-            while (item.compareTo(arr[pos]) == 0) {
-                pos += 1;
+            // Ignore all duplicate elements
+            while (item.compareTo(array[pos]) == 0) {
+                pos++;
             }
 
-            // put the item to it's right position
-            if (pos != j) {
-                item = replace(arr, pos, item);
+            // Put the item to its correct position
+            if (pos != cycleStart) {
+                item = replace(array, pos, item);
             }
 
-            // Rotate rest of the cycle
-            while (pos != j) {
-                pos = j;
+            // Rotate the rest of the cycle
+            while (pos != cycleStart) {
+                pos = cycleStart;
 
-                // Find position where we put the element
-                for (int i = j + 1; i < n; i++) {
-                    if (less(arr[i], item)) {
-                        pos += 1;
+                // Find the position where we put the element
+                for (int i = cycleStart + 1; i < array.length; i++) {
+                    if (SortUtils.less(array[i], item)) {
+                        pos++;
                     }
                 }
 
-                // ignore all duplicate elements
-                while (item.compareTo(arr[pos]) == 0) {
-                    pos += 1;
+                // Ignore all duplicate elements
+                while (item.compareTo(array[pos]) == 0) {
+                    pos++;
                 }
 
-                // put the item to it's right position
-                if (item != arr[pos]) {
-                    item = replace(arr, pos, item);
+                // Put the item to its correct position
+                if (item != array[pos]) {
+                    item = replace(array, pos, item);
                 }
             }
         }
-
-        return arr;
-    }
-
-    private <T extends Comparable<T>> T replace(T[] arr, int pos, T item) {
-        T temp = item;
-        item = arr[pos];
-        arr[pos] = temp;
-        return item;
+        return array;
     }
 
-    public static void main(String[] args) {
-        Integer[] arr = {
-            4,
-            23,
-            6,
-            78,
-            1,
-            26,
-            11,
-            23,
-            0,
-            -6,
-            3,
-            54,
-            231,
-            9,
-            12,
-        };
-        CycleSort cycleSort = new CycleSort();
-        cycleSort.sort(arr);
-
-        System.out.println("After sort : ");
-        print(arr);
+    /**
+     * Replaces an element in the array with the given item and returns the replaced item.
+     *
+     * @param array the array in which the replacement will occur
+     * @param pos the position at which the replacement will occur
+     * @param item the item to be placed in the array
+     * @param <T> the type of elements in the array, must be comparable
+     * @return the replaced item
+     */
+    private <T extends Comparable<T>> T replace(T[] array, int pos, T item) {
+        T replacedItem = array[pos];
+        array[pos] = item;
+        return replacedItem;
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/CycleSortTest.java b/src/test/java/com/thealgorithms/sorts/CycleSortTest.java
new file mode 100644
index 000000000000..b8c3d1653713
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/CycleSortTest.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.sorts;
+
+public class CycleSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new CycleSort();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java b/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java
index e6aedc3f06ac..43de55018071 100644
--- a/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java
@@ -1,11 +1,14 @@
 package com.thealgorithms.sorts;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertIterableEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
+import java.util.Objects;
 import org.junit.jupiter.api.Test;
 
 public abstract class SortingAlgorithmTest {
@@ -171,4 +174,192 @@ void shouldAcceptWhenRandomListIsPassed() {
         List<Double> sorted = getSortAlgorithm().sort(list);
         assertTrue(SortUtils.isSorted(sorted));
     }
+
+    @Test
+    public void shouldAcceptWhenArrayWithAllIdenticalValuesIsPassed() {
+        Integer[] array = {1, 1, 1, 1};
+        Integer[] sortedArray = getSortAlgorithm().sort(array);
+        assertArrayEquals(new Integer[] {1, 1, 1, 1}, sortedArray);
+    }
+
+    @Test
+    public void shouldAcceptWhenListWithAllIdenticalValuesIsPassed() {
+        List<Integer> list = Arrays.asList(1, 1, 1, 1);
+        List<Integer> sortedList = getSortAlgorithm().sort(list);
+        assertEquals(Arrays.asList(1, 1, 1, 1), sortedList);
+    }
+
+    @Test
+    public void shouldAcceptWhenArrayWithMixedPositiveAndNegativeValuesIsPassed() {
+        Integer[] array = {-1, 3, -2, 5, 0};
+        Integer[] sortedArray = getSortAlgorithm().sort(array);
+        assertArrayEquals(new Integer[] {-2, -1, 0, 3, 5}, sortedArray);
+    }
+
+    @Test
+    public void shouldAcceptWhenListWithMixedPositiveAndNegativeValuesIsPassed() {
+        List<Integer> list = Arrays.asList(-1, 3, -2, 5, 0);
+        List<Integer> sortedList = getSortAlgorithm().sort(list);
+        assertEquals(Arrays.asList(-2, -1, 0, 3, 5), sortedList);
+    }
+
+    @Test
+    public void shouldAcceptWhenArrayWithLargeNumbersIsPassed() {
+        Long[] array = {10000000000L, 9999999999L, 10000000001L};
+        Long[] sortedArray = getSortAlgorithm().sort(array);
+        assertArrayEquals(new Long[] {9999999999L, 10000000000L, 10000000001L}, sortedArray);
+    }
+
+    @Test
+    public void shouldAcceptWhenListWithLargeNumbersIsPassed() {
+        List<Long> list = Arrays.asList(10000000000L, 9999999999L, 10000000001L);
+        List<Long> sortedList = getSortAlgorithm().sort(list);
+        assertEquals(Arrays.asList(9999999999L, 10000000000L, 10000000001L), sortedList);
+    }
+
+    @Test
+    public void shouldAcceptWhenArrayWithMaxIntegerValuesIsPassed() {
+        Integer[] array = {Integer.MAX_VALUE, Integer.MIN_VALUE, 0};
+        Integer[] sortedArray = getSortAlgorithm().sort(array);
+        assertArrayEquals(new Integer[] {Integer.MIN_VALUE, 0, Integer.MAX_VALUE}, sortedArray);
+    }
+
+    @Test
+    public void shouldAcceptWhenListWithMaxIntegerValuesIsPassed() {
+        List<Integer> list = Arrays.asList(Integer.MAX_VALUE, Integer.MIN_VALUE, 0);
+        List<Integer> sortedList = getSortAlgorithm().sort(list);
+        assertEquals(Arrays.asList(Integer.MIN_VALUE, 0, Integer.MAX_VALUE), sortedList);
+    }
+
+    @Test
+    public void shouldAcceptWhenArrayWithMinIntegerValuesIsPassed() {
+        Integer[] array = {Integer.MIN_VALUE, Integer.MAX_VALUE, 0};
+        Integer[] sortedArray = getSortAlgorithm().sort(array);
+        assertArrayEquals(new Integer[] {Integer.MIN_VALUE, 0, Integer.MAX_VALUE}, sortedArray);
+    }
+
+    @Test
+    public void shouldAcceptWhenListWithMinIntegerValuesIsPassed() {
+        List<Integer> list = Arrays.asList(Integer.MIN_VALUE, Integer.MAX_VALUE, 0);
+        List<Integer> sortedList = getSortAlgorithm().sort(list);
+        assertEquals(Arrays.asList(Integer.MIN_VALUE, 0, Integer.MAX_VALUE), sortedList);
+    }
+
+    @Test
+    public void shouldAcceptWhenArrayWithSpecialCharactersIsPassed() {
+        String[] array = {"!", "@", "#", "$"};
+        String[] sortedArray = getSortAlgorithm().sort(array);
+        assertArrayEquals(new String[] {"!", "#", "$", "@"}, sortedArray);
+    }
+
+    @Test
+    public void shouldAcceptWhenListWithSpecialCharactersIsPassed() {
+        List<String> list = Arrays.asList("!", "@", "#", "$");
+        List<String> sortedList = getSortAlgorithm().sort(list);
+        assertEquals(Arrays.asList("!", "#", "$", "@"), sortedList);
+    }
+
+    @Test
+    public void shouldAcceptWhenArrayWithMixedCaseStringsIsPassed() {
+        String[] array = {"apple", "Banana", "cherry", "Date"};
+        String[] sortedArray = getSortAlgorithm().sort(array);
+        assertArrayEquals(new String[] {"Banana", "Date", "apple", "cherry"}, sortedArray);
+    }
+
+    @Test
+    public void shouldAcceptWhenListWithMixedCaseStringsIsPassed() {
+        List<String> list = Arrays.asList("apple", "Banana", "cherry", "Date");
+        List<String> sortedList = getSortAlgorithm().sort(list);
+        assertEquals(Arrays.asList("Banana", "Date", "apple", "cherry"), sortedList);
+    }
+
+    @Test
+    public void shouldHandleArrayWithNullValues() {
+        Integer[] array = {3, null, 2, null, 1};
+        org.junit.jupiter.api.Assertions.assertThrows(NullPointerException.class, () -> getSortAlgorithm().sort(array));
+    }
+
+    @Test
+    public void shouldHandleListWithNullValues() {
+        List<Integer> list = Arrays.asList(3, null, 2, null, 1);
+        org.junit.jupiter.api.Assertions.assertThrows(NullPointerException.class, () -> getSortAlgorithm().sort(list));
+    }
+
+    static class CustomObject implements Comparable<CustomObject> {
+        int value;
+
+        CustomObject(int value) {
+            this.value = value;
+        }
+
+        @Override
+        public int compareTo(CustomObject o) {
+            return Integer.compare(this.value, o.value);
+        }
+
+        @Override
+        public String toString() {
+            return "CustomObject{"
+                + "value=" + value + '}';
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            CustomObject that = (CustomObject) o;
+            return value == that.value;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hashCode(value);
+        }
+    }
+
+    @Test
+    public void shouldHandleArrayOfCustomObjects() {
+        CustomObject[] array = {new CustomObject(3), new CustomObject(1), new CustomObject(2)};
+        CustomObject[] sortedArray = getSortAlgorithm().sort(array);
+        assertArrayEquals(new CustomObject[] {new CustomObject(1), new CustomObject(2), new CustomObject(3)}, sortedArray);
+    }
+
+    @Test
+    public void shouldHandleListOfCustomObjects() {
+        List<CustomObject> list = Arrays.asList(new CustomObject(3), new CustomObject(1), new CustomObject(2));
+        List<CustomObject> sortedList = getSortAlgorithm().sort(list);
+        assertEquals(Arrays.asList(new CustomObject(1), new CustomObject(2), new CustomObject(3)), sortedList);
+    }
+
+    @Test
+    public void shouldHandleArrayOfFloatingPointNumbers() {
+        Double[] array = {3.3, 2.2, 1.1, Double.NaN, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY};
+        Double[] sortedArray = getSortAlgorithm().sort(array);
+        assertArrayEquals(new Double[] {Double.NEGATIVE_INFINITY, 1.1, 2.2, 3.3, Double.POSITIVE_INFINITY, Double.NaN}, sortedArray);
+    }
+
+    @Test
+    public void shouldHandleListOfFloatingPointNumbers() {
+        List<Double> list = Arrays.asList(3.3, 2.2, 1.1, Double.NaN, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY);
+        List<Double> sortedList = getSortAlgorithm().sort(list);
+        assertEquals(Arrays.asList(Double.NEGATIVE_INFINITY, 1.1, 2.2, 3.3, Double.POSITIVE_INFINITY, Double.NaN), sortedList);
+    }
+
+    @Test
+    public void shouldHandleArrayWithEmptyStrings() {
+        String[] array = {"apple", "", "banana", ""};
+        String[] sortedArray = getSortAlgorithm().sort(array);
+        assertArrayEquals(new String[] {"", "", "apple", "banana"}, sortedArray);
+    }
+
+    @Test
+    public void shouldHandleListWithEmptyStrings() {
+        List<String> list = Arrays.asList("apple", "", "banana", "");
+        List<String> sortedList = getSortAlgorithm().sort(list);
+        assertEquals(Arrays.asList("", "", "apple", "banana"), sortedList);
+    }
 }

From 5840579885e5132b6f2f9997d78707f3dcb63a14 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 16 Jul 2024 10:39:11 +0200
Subject: [PATCH 0245/1338] style: include `BigIntegerInstantiation` (#5294)

---
 pmd-exclude.properties                               |  3 +--
 .../thealgorithms/maths/FibonacciJavaStreams.java    |  2 +-
 .../maths/FibonacciJavaStreamsTest.java              |  6 +++---
 .../java/com/thealgorithms/maths/MatrixUtilTest.java | 12 ++++++------
 4 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index b7bc6f074d02..1e7a09549aca 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -39,7 +39,6 @@ com.thealgorithms.dynamicprogramming.WineProblem=UselessParentheses
 com.thealgorithms.maths.BinomialCoefficient=UselessParentheses
 com.thealgorithms.maths.Complex=UselessParentheses
 com.thealgorithms.maths.DistanceFormulaTest=UnnecessaryFullyQualifiedName
-com.thealgorithms.maths.FibonacciJavaStreamsTest=BigIntegerInstantiation
 com.thealgorithms.maths.Gaussian=UselessParentheses
 com.thealgorithms.maths.GcdSolutionWrapper=UselessParentheses
 com.thealgorithms.maths.HeronsFormula=UselessParentheses
@@ -47,7 +46,7 @@ com.thealgorithms.maths.KaprekarNumbers=UselessParentheses
 com.thealgorithms.maths.KeithNumber=UselessParentheses
 com.thealgorithms.maths.LeonardoNumber=UselessParentheses
 com.thealgorithms.maths.LinearDiophantineEquationsSolver=UselessParentheses
-com.thealgorithms.maths.MatrixUtil=BigIntegerInstantiation,UselessParentheses
+com.thealgorithms.maths.MatrixUtil=UselessParentheses
 com.thealgorithms.maths.RomanNumeralUtil=UselessParentheses
 com.thealgorithms.maths.SecondMinMax=UselessParentheses
 com.thealgorithms.maths.SecondMinMaxTest=UnnecessaryFullyQualifiedName
diff --git a/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java b/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java
index 72bae57c27b0..84390860ccc4 100644
--- a/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java
+++ b/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java
@@ -22,7 +22,7 @@ public static Optional<BigDecimal> calculate(final BigDecimal index) {
             return Optional.of(BigDecimal.ZERO);
         }
 
-        if (index.compareTo(new BigDecimal(2)) < 0) {
+        if (index.compareTo(BigDecimal.TWO) < 0) {
             return Optional.of(BigDecimal.ONE);
         }
 
diff --git a/src/test/java/com/thealgorithms/maths/FibonacciJavaStreamsTest.java b/src/test/java/com/thealgorithms/maths/FibonacciJavaStreamsTest.java
index 2c81a6304d8f..5cfb304ae471 100644
--- a/src/test/java/com/thealgorithms/maths/FibonacciJavaStreamsTest.java
+++ b/src/test/java/com/thealgorithms/maths/FibonacciJavaStreamsTest.java
@@ -21,13 +21,13 @@ public void testWithNegativeIndexShouldThrowException() {
     public void testCheckTheFirst4SequenceElements() {
         checkElement(BigDecimal.ZERO, BigDecimal.ZERO);
         checkElement(BigDecimal.ONE, BigDecimal.ONE);
-        checkElement(new BigDecimal(2), BigDecimal.ONE);
-        checkElement(new BigDecimal(3), new BigDecimal(2));
+        checkElement(BigDecimal.TWO, BigDecimal.ONE);
+        checkElement(new BigDecimal(3), BigDecimal.TWO);
     }
 
     @Test
     public void testCheck10thSequenceElement() {
-        checkElement(new BigDecimal(10), new BigDecimal(55));
+        checkElement(BigDecimal.TEN, new BigDecimal(55));
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java b/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java
index f61ebe6a26cc..b954e6ff7511 100644
--- a/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java
+++ b/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java
@@ -11,20 +11,20 @@ class MatrixUtilTest {
     @Test
     void add() {
         final BigDecimal[][] matrix1 = {
-            {new BigDecimal(3), new BigDecimal(2)},
+            {new BigDecimal(3), BigDecimal.TWO},
             {BigDecimal.ZERO, BigDecimal.ONE},
         };
 
         final BigDecimal[][] matrix2 = {
             {BigDecimal.ONE, new BigDecimal(3)},
-            {new BigDecimal(2), BigDecimal.ZERO},
+            {BigDecimal.TWO, BigDecimal.ZERO},
         };
 
         final BigDecimal[][] actual = MatrixUtil.add(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
 
         final BigDecimal[][] expected = {
             {new BigDecimal(4), new BigDecimal(5)},
-            {new BigDecimal(2), BigDecimal.ONE},
+            {BigDecimal.TWO, BigDecimal.ONE},
         };
 
         assertTrue(Objects.deepEquals(actual, expected));
@@ -37,7 +37,7 @@ void subtract() {
         };
 
         final BigDecimal[][] matrix2 = {
-            {new BigDecimal(2), BigDecimal.ZERO},
+            {BigDecimal.TWO, BigDecimal.ZERO},
             {new BigDecimal(-2), new BigDecimal(-3)},
         };
 
@@ -55,13 +55,13 @@ void subtract() {
     void multiply() {
 
         final BigDecimal[][] matrix1 = {
-            {BigDecimal.ONE, new BigDecimal(2), new BigDecimal(3)},
+            {BigDecimal.ONE, BigDecimal.TWO, new BigDecimal(3)},
             {new BigDecimal(4), new BigDecimal(5), new BigDecimal(6)},
             {new BigDecimal(7), new BigDecimal(8), new BigDecimal(9)},
         };
 
         final BigDecimal[][] matrix2 = {
-            {BigDecimal.ONE, new BigDecimal(2)},
+            {BigDecimal.ONE, BigDecimal.TWO},
             {new BigDecimal(3), new BigDecimal(4)},
             {new BigDecimal(5), new BigDecimal(6)},
         };

From ff0eca3caaaa91423248908216f29c6e1b8cc367 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 16 Jul 2024 11:57:28 +0300
Subject: [PATCH 0246/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-pmd-plugin from 3.23.0 to 3.24.0 (#5292)

---
 DIRECTORY.md | 17 +++++++++++------
 pom.xml      |  2 +-
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 02ad74351bd7..191158bf6da0 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -494,8 +494,8 @@
             * [BucketSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BucketSort.java)
             * [CircleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CircleSort.java)
             * [CocktailShakerSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java)
-            * [CountingSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CountingSort.java)
             * [CombSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CombSort.java)
+            * [CountingSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CountingSort.java)
             * [CycleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CycleSort.java)
             * [DNFSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DNFSort.java)
             * [DualPivotQuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java)
@@ -528,8 +528,8 @@
             * [TimSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/TimSort.java)
             * [TopologicalSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/TopologicalSort.java)
             * [TreeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/TreeSort.java)
-            * [WiggleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/WiggleSort.java)
             * [WaveSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/WaveSort.java)
+            * [WiggleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/WiggleSort.java)
           * stacks
             * [BalancedBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java)
             * [DecimalToAnyUsingStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java)
@@ -761,6 +761,7 @@
             * [LongDivisionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LongDivisionTest.java)
             * [LucasSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LucasSeriesTest.java)
             * [MatrixRankTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MatrixRankTest.java)
+            * [MatrixUtilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java)
             * [MaxValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MaxValueTest.java)
             * [MeansTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MeansTest.java)
             * [MedianTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MedianTest.java)
@@ -831,6 +832,7 @@
             * [NextFitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/NextFitTest.java)
             * [PasswordGenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/PasswordGenTest.java)
             * [SieveOfEratosthenesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SieveOfEratosthenesTest.java)
+            * [StringMatchFiniteAutomataTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java)
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
@@ -857,14 +859,15 @@
           * sorts
             * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
             * [BinaryInsertionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java)
+            * [BitonicSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java)
             * [BogoSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BogoSortTest.java)
-            * [BubbleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BubbleSortTest.java)
             * [BubbleSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BubbleSortRecursiveTest.java)
+            * [BubbleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BubbleSortTest.java)
             * [BucketSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BucketSortTest.java)
             * [CircleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CircleSortTest.java)
             * [CocktailShakerSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java)
-            * [CountingSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CountingSortTest.java)
             * [CombSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CombSortTest.java)
+            * [CountingSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CountingSortTest.java)
             * [CycleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CycleSortTest.java)
             * [DualPivotQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java)
             * [DutchNationalFlagSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java)
@@ -873,13 +876,14 @@
             * [HeapSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/HeapSortTest.java)
             * [InsertionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java)
             * [IntrospectiveSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java)
+            * [MergeSortNoExtraSpaceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/MergeSortNoExtraSpaceTest.java)
             * [MergeSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/MergeSortRecursiveTest.java)
             * [MergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/MergeSortTest.java)
             * [OddEvenSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/OddEvenSortTest.java)
             * [PancakeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java)
             * [QuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/QuickSortTest.java)
-            * [SelectionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java)
             * [SelectionSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java)
+            * [SelectionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java)
             * [ShellSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/ShellSortTest.java)
             * [SimpleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SimpleSortTest.java)
             * [SlowSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SlowSortTest.java)
@@ -887,11 +891,12 @@
             * [SortUtilsRandomGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortUtilsRandomGeneratorTest.java)
             * [SortUtilsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java)
             * [StrandSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StrandSortTest.java)
+            * [SwapSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SwapSortTest.java)
             * [TimSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TimSortTest.java)
             * [TopologicalSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java)
             * [TreeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TreeSortTest.java)
-            * [WiggleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java)
             * [WaveSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WaveSortTest.java)
+            * [WiggleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java)
           * stacks
             * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
           * strings
diff --git a/pom.xml b/pom.xml
index 7e363fcf258a..e08faac6385b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -146,7 +146,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-pmd-plugin</artifactId>
-                <version>3.23.0</version>
+                <version>3.24.0</version>
                 <configuration>
                     <printFailingErrors>true</printFailingErrors>
                     <includeTests>true</includeTests>

From f584cd9a98f9a38d8ae930456fd69c0927220508 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 16 Jul 2024 11:05:17 +0200
Subject: [PATCH 0247/1338] Chore(deps): bump gitpod/workspace-java-21 from
 2024-07-02-14-18-47 to 2024-07-14-17-19-51 (#5293)

Chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2024-07-02-14-18-47 to 2024-07-14-17-19-51.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 99a25f592e0a..e6d0001e5571 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-07-02-14-18-47
+FROM gitpod/workspace-java-21:2024-07-14-17-19-51
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From f1e26064a52096448c84037c08435f19adef60a4 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 18 Jul 2024 08:27:37 +0200
Subject: [PATCH 0248/1338] Chore(deps): bump org.apache.commons:commons-lang3
 from 3.14.0 to 3.15.0 (#5296)

Bumps org.apache.commons:commons-lang3 from 3.14.0 to 3.15.0.

---
updated-dependencies:
- dependency-name: org.apache.commons:commons-lang3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index e08faac6385b..0c01353aa5dd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -50,7 +50,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
-            <version>3.14.0</version>
+            <version>3.15.0</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>

From 94032148ca52092248ef43e8d7c0fa9ff6737e49 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 19 Jul 2024 18:24:55 +0200
Subject: [PATCH 0249/1338] refactor: cleanup `RadixSort` (#5280)

* refactor: refactoring RadixSort, adding test, update DIRECTORY.md

* checkstyle: fix formatting for test

* refactor: adding possibility to sort negative numbers. Improve tests. Improving code readability

* checkstyle: fix formatting

* refactor: resolve conflicts with master branch

* refactor: remove negative integers support

* checkstyle: fix formatting

* checkstyle: fix formatting, revert test

* refactor: adding return array to countDigits and buildOutput method, adding more specific description to javadocs

---------

Co-authored-by: Alex Klymenko <alx@alx.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 DIRECTORY.md                                  |   1 +
 .../com/thealgorithms/sorts/RadixSort.java    | 108 ++++++++++++------
 .../thealgorithms/sorts/RadixSortTest.java    |  30 +++++
 3 files changed, 103 insertions(+), 36 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/sorts/RadixSortTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 191158bf6da0..ef7d163a5704 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -882,6 +882,7 @@
             * [OddEvenSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/OddEvenSortTest.java)
             * [PancakeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java)
             * [QuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/QuickSortTest.java)
+            * [RadixSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/RadixSortTest.java)
             * [SelectionSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java)
             * [SelectionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java)
             * [ShellSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/ShellSortTest.java)
diff --git a/src/main/java/com/thealgorithms/sorts/RadixSort.java b/src/main/java/com/thealgorithms/sorts/RadixSort.java
index a87097bf6e9d..f0201a5a84b8 100644
--- a/src/main/java/com/thealgorithms/sorts/RadixSort.java
+++ b/src/main/java/com/thealgorithms/sorts/RadixSort.java
@@ -1,62 +1,98 @@
 package com.thealgorithms.sorts;
 
+import com.thealgorithms.maths.NumberOfDigits;
 import java.util.Arrays;
 
-final class RadixSort {
+/**
+ * This class provides an implementation of the radix sort algorithm.
+ * It sorts an array of nonnegative integers in increasing order.
+ */
+public final class RadixSort {
+    private static final int BASE = 10;
+
     private RadixSort() {
     }
 
-    private static int getMax(int[] arr, int n) {
-        int mx = arr[0];
-        for (int i = 1; i < n; i++) {
-            if (arr[i] > mx) {
-                mx = arr[i];
-            }
+    /**
+     * Sorts an array of nonnegative integers using the radix sort algorithm.
+     *
+     * @param array the array to be sorted
+     * @return the sorted array
+     * @throws IllegalArgumentException if any negative integers are found
+     */
+    public static int[] sort(int[] array) {
+        if (array.length == 0) {
+            return array;
         }
-        return mx;
-    }
 
-    private static void countSort(int[] arr, int n, int exp) {
-        int[] output = new int[n];
-        int i;
-        int[] count = new int[10];
-        Arrays.fill(count, 0);
+        checkForNegativeInput(array);
+        radixSort(array);
+        return array;
+    }
 
-        for (i = 0; i < n; i++) {
-            count[(arr[i] / exp) % 10]++;
+    /**
+     * Checks if the array contains any negative integers.
+     *
+     * @param array the array to be checked
+     * @throws IllegalArgumentException if any negative integers are found
+     */
+    private static void checkForNegativeInput(int[] array) {
+        for (int number : array) {
+            if (number < 0) {
+                throw new IllegalArgumentException("Array contains non-positive integers.");
+            }
         }
+    }
 
-        for (i = 1; i < 10; i++) {
-            count[i] += count[i - 1];
+    private static void radixSort(int[] array) {
+        final int max = Arrays.stream(array).max().getAsInt();
+        for (int i = 0, exp = 1; i < NumberOfDigits.numberOfDigits(max); i++, exp *= BASE) {
+            countingSortByDigit(array, exp);
         }
+    }
 
-        for (i = n - 1; i >= 0; i--) {
-            output[count[(arr[i] / exp) % 10] - 1] = arr[i];
-            count[(arr[i] / exp) % 10]--;
-        }
+    /**
+     * A utility method to perform counting sort of array[] according to the digit represented by exp.
+     *
+     * @param array the array to be sorted
+     * @param exp   the exponent representing the current digit position
+     */
+    private static void countingSortByDigit(int[] array, int exp) {
+        int[] count = countDigits(array, exp);
+        accumulateCounts(count);
+        int[] output = buildOutput(array, exp, count);
+        copyOutput(array, output);
+    }
 
-        System.arraycopy(output, 0, arr, 0, n);
+    private static int[] countDigits(int[] array, int exp) {
+        int[] count = new int[BASE];
+        for (int i = 0; i < array.length; i++) {
+            count[getDigit(array[i], exp)]++;
+        }
+        return count;
     }
 
-    private static void radixsort(int[] arr, int n) {
-        int m = getMax(arr, n);
+    private static int getDigit(int number, int position) {
+        return (number / position) % BASE;
+    }
 
-        for (int exp = 1; m / exp > 0; exp *= 10) {
-            countSort(arr, n, exp);
+    private static void accumulateCounts(int[] count) {
+        for (int i = 1; i < BASE; i++) {
+            count[i] += count[i - 1];
         }
     }
 
-    static void print(int[] arr, int n) {
-        for (int i = 0; i < n; i++) {
-            System.out.print(arr[i] + " ");
+    private static int[] buildOutput(int[] array, int exp, int[] count) {
+        int[] output = new int[array.length];
+        for (int i = array.length - 1; i >= 0; i--) {
+            int digit = getDigit(array[i], exp);
+            output[count[digit] - 1] = array[i];
+            count[digit]--;
         }
+        return output;
     }
 
-    public static void main(String[] args) {
-        int[] arr = {170, 45, 75, 90, 802, 24, 2, 66};
-        int n = arr.length;
-        radixsort(arr, n);
-        print(arr, n);
+    private static void copyOutput(int[] array, int[] output) {
+        System.arraycopy(output, 0, array, 0, array.length);
     }
 }
-// Written by James Mc Dermott(theycallmemac)
diff --git a/src/test/java/com/thealgorithms/sorts/RadixSortTest.java b/src/test/java/com/thealgorithms/sorts/RadixSortTest.java
new file mode 100644
index 000000000000..24ab52b199aa
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/RadixSortTest.java
@@ -0,0 +1,30 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class RadixSortTest {
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void test(int[] inputArray, int[] expectedArray) {
+        assertArrayEquals(RadixSort.sort(inputArray), expectedArray);
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new int[] {170, 45, 75, 90, 802, 24, 2, 66}, new int[] {2, 24, 45, 66, 75, 90, 170, 802}), Arguments.of(new int[] {3, 3, 3, 3}, new int[] {3, 3, 3, 3}), Arguments.of(new int[] {9, 4, 6, 8, 14, 3}, new int[] {3, 4, 6, 8, 9, 14}),
+            Arguments.of(new int[] {10, 90, 49, 2, 1, 5, 23}, new int[] {1, 2, 5, 10, 23, 49, 90}), Arguments.of(new int[] {1, 3, 4, 2, 7, 8}, new int[] {1, 2, 3, 4, 7, 8}), Arguments.of(new int[] {}, new int[] {}), Arguments.of(new int[] {1}, new int[] {1}),
+            Arguments.of(new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9}, new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9}), Arguments.of(new int[] {9, 8, 7, 6, 5, 4, 3, 2, 1}, new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9}),
+            Arguments.of(new int[] {1000000000, 999999999, 888888888, 777777777}, new int[] {777777777, 888888888, 999999999, 1000000000}), Arguments.of(new int[] {123, 9, 54321, 123456789, 0}, new int[] {0, 9, 123, 54321, 123456789}));
+    }
+
+    @Test
+    public void testWithNegativeNumbers() {
+        assertThrows(IllegalArgumentException.class, () -> RadixSort.sort(new int[] {3, 1, 4, 1, 5, -9}));
+    }
+}

From 97d416e64e0093bd28f64c36c9d29b59137d569e Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 20 Jul 2024 21:28:06 +0200
Subject: [PATCH 0250/1338] refactor: cleanup `StoogeSort` (#5283)

* refactor: cleanup StoogeSort

* refactor: update DIRECTORY.md for StoogeSortTest

---------

Co-authored-by: Alex Klymenko <alx@alx.com>
---
 DIRECTORY.md                                  |  1 +
 .../com/thealgorithms/sorts/StoogeSort.java   | 29 ++++---------------
 .../thealgorithms/sorts/StoogeSortTest.java   | 12 ++++++++
 3 files changed, 19 insertions(+), 23 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/sorts/StoogeSortTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index ef7d163a5704..0c14970bf481 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -891,6 +891,7 @@
             * [SortingAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java)
             * [SortUtilsRandomGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortUtilsRandomGeneratorTest.java)
             * [SortUtilsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java)
+            * [StoogeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StoogeSortTest.java)
             * [StrandSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StrandSortTest.java)
             * [SwapSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SwapSortTest.java)
             * [TimSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TimSortTest.java)
diff --git a/src/main/java/com/thealgorithms/sorts/StoogeSort.java b/src/main/java/com/thealgorithms/sorts/StoogeSort.java
index 330f9752d1e4..25830109638a 100644
--- a/src/main/java/com/thealgorithms/sorts/StoogeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/StoogeSort.java
@@ -7,9 +7,12 @@
 public class StoogeSort implements SortAlgorithm {
 
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] unsortedArray) {
-        sort(unsortedArray, 0, unsortedArray.length);
-        return unsortedArray;
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array.length == 0) {
+            return array;
+        }
+        sort(array, 0, array.length);
+        return array;
     }
 
     public <T extends Comparable<T>> T[] sort(T[] unsortedArray, int start, int end) {
@@ -28,24 +31,4 @@ public <T extends Comparable<T>> T[] sort(T[] unsortedArray, int start, int end)
         }
         return unsortedArray;
     }
-
-    public static void main(String[] args) {
-        StoogeSort stoogeSort = new StoogeSort();
-
-        Integer[] integerArray = {8, 84, 53, 953, 64, 2, 202};
-        // Print integerArray unsorted
-        SortUtils.print(integerArray);
-
-        stoogeSort.sort(integerArray);
-        // Print integerArray sorted
-        SortUtils.print(integerArray);
-
-        String[] stringArray = {"g", "d", "a", "b", "f", "c", "e"};
-        // Print stringArray unsorted
-        SortUtils.print(stringArray);
-
-        stoogeSort.sort(stringArray);
-        // Print stringArray sorted
-        SortUtils.print(stringArray);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/StoogeSortTest.java b/src/test/java/com/thealgorithms/sorts/StoogeSortTest.java
new file mode 100644
index 000000000000..e230ac2ac590
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/StoogeSortTest.java
@@ -0,0 +1,12 @@
+package com.thealgorithms.sorts;
+
+public class StoogeSortTest extends SortingAlgorithmTest {
+    protected int getGeneratedArraySize() {
+        return 1000;
+    }
+
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new StoogeSort();
+    }
+}

From 08db744240782df6a4e985be157275d88cc99ef6 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 22 Jul 2024 09:20:59 +0200
Subject: [PATCH 0251/1338] refactor: cleanup `PancakeSort` (#5295)

* refactor: PancakeSort cleanup, changing test to standard

* checkstyle: fix formatting

---------

Co-authored-by: alxklm <alx@alx.com>
---
 .../com/thealgorithms/sorts/PancakeSort.java  | 71 ++++++----------
 .../thealgorithms/sorts/PancakeSortTest.java  | 80 +------------------
 2 files changed, 29 insertions(+), 122 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/PancakeSort.java b/src/main/java/com/thealgorithms/sorts/PancakeSort.java
index cd3e89307238..6079672a1d77 100644
--- a/src/main/java/com/thealgorithms/sorts/PancakeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/PancakeSort.java
@@ -10,56 +10,35 @@ public class PancakeSort implements SortAlgorithm {
 
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
-        int size = array.length;
+        if (array.length < 2) {
+            return array;
+        }
 
-        for (int i = 0; i < size; i++) {
-            T max = array[0];
-            int index = 0;
-            for (int j = 0; j < size - i; j++) {
-                if (SortUtils.less(max, array[j])) {
-                    max = array[j];
-                    index = j;
-                }
-            }
-            SortUtils.flip(array, index, array.length - 1 - i);
+        for (int currentSize = 0; currentSize < array.length; currentSize++) {
+            int maxIndex = findMaxIndex(array, currentSize);
+            SortUtils.flip(array, maxIndex, array.length - 1 - currentSize);
         }
+
         return array;
     }
 
-    public static void main(String[] args) {
-        Integer[] arr = {
-            10,
-            9,
-            8,
-            7,
-            6,
-            15,
-            14,
-            7,
-            4,
-            3,
-            8,
-            6,
-            3,
-            1,
-            2,
-            -2,
-            -5,
-            -8,
-            -3,
-            -1,
-            13,
-            12,
-            11,
-            5,
-            4,
-            3,
-            2,
-            1,
-        };
-        PancakeSort pancakeSort = new PancakeSort();
-        System.out.println("After sorting:");
-        pancakeSort.sort(arr);
-        SortUtils.print(arr);
+    /**
+     * Finds the index of the maximum element in the array up to the given size.
+     *
+     * @param array      the array to be searched
+     * @param currentSize the current size of the unsorted portion of the array
+     * @param <T>        the type of elements in the array
+     * @return the index of the maximum element
+     */
+    private <T extends Comparable<T>> int findMaxIndex(T[] array, int currentSize) {
+        T max = array[0];
+        int maxIndex = 0;
+        for (int i = 0; i < array.length - currentSize; i++) {
+            if (SortUtils.less(max, array[i])) {
+                max = array[i];
+                maxIndex = i;
+            }
+        }
+        return maxIndex;
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java b/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java
index 8d26532a1acd..0039bdfb03e7 100644
--- a/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java
@@ -1,80 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
-import org.junit.jupiter.api.DisplayName;
-import org.junit.jupiter.api.Test;
-
-public class PancakeSortTest {
-
-    private PancakeSort pancakeSort = new PancakeSort();
-
-    @Test
-    @DisplayName("Empty Array pancakeSort")
-    public void pancakeSortEmptyArray() {
-        Integer[] inputArray = {};
-        Integer[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEmpty();
-    }
-
-    @Test
-    @DisplayName("PancakeSort single Integer Array")
-    public void pancakeSort() {
-        Integer[] inputArray = {2};
-        Integer[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(inputArray);
-    }
-
-    @Test
-    @DisplayName("PancakeSort non duplicate Integer Array")
-    public void pancakeSortNonDuplicateIntegerArray() {
-        Integer[] inputArray = {2, 1, 77, 34, 14, 56, 8};
-        Integer[] expectedOutput = {1, 2, 8, 14, 34, 56, 77};
-        Integer[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(expectedOutput);
-    }
-
-    @Test
-    @DisplayName("PancakeSort Integer Array with duplicates")
-    public void pancakeSortDuplicateIntegerArray() {
-        Integer[] inputArray = {2, 1, 77, 34, 14, 77, 56, 14, 8};
-        Integer[] expectedOutput = {1, 2, 8, 14, 14, 34, 56, 77, 77};
-        Integer[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(expectedOutput);
-    }
-
-    @Test
-    @DisplayName("PancakeSort negative Integer Array with duplicates")
-    public void pancakeSortNegativeDuplicateIntegerArray() {
-        Integer[] inputArray = {2, 1, 77, -34, -14, 77, 56, -14, 8};
-        Integer[] expectedOutput = {-34, -14, -14, 1, 2, 8, 56, 77, 77};
-        Integer[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(expectedOutput);
-    }
-
-    @Test
-    @DisplayName("PancakeSort single String Array")
-    public void pancakeSortSingleStringArray() {
-        String[] inputArray = {"W"};
-        String[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(inputArray);
-    }
-
-    @Test
-    @DisplayName("PancakeSort non duplicate String Array")
-    public void pancakeSortNonDuplicateStringArray() {
-        String[] inputArray = {"W", "A", "d", "be", "jk", "hb", "bgh"};
-        String[] expectedOutput = {"A", "W", "be", "bgh", "d", "hb", "jk"};
-        String[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(expectedOutput);
-    }
-
-    @Test
-    @DisplayName("PancakeSort String Array with duplicates")
-    public void pancakeSortDuplicateStringArray() {
-        String[] inputArray = {"W", "A", "d", "be", "jk", "hb", "bgh", "bgh", "W"};
-        String[] expectedOutput = {"A", "W", "W", "be", "bgh", "bgh", "d", "hb", "jk"};
-        String[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(expectedOutput);
+public class PancakeSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new PancakeSort();
     }
 }

From 76a450fb75613c07c337af1604e31237f307c6c9 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 24 Jul 2024 18:32:47 +0300
Subject: [PATCH 0252/1338] feat: add `PatienceSort` (#5288)

* feat: PatienceSort

* refactor: fix readability issues,a and redundant check

---------

Co-authored-by: alxklm <alx@alx.com>
---
 DIRECTORY.md                                  |   2 +
 .../com/thealgorithms/sorts/PatienceSort.java | 112 ++++++++++++++++++
 .../thealgorithms/sorts/PatienceSortTest.java |   8 ++
 3 files changed, 122 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/PatienceSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/PatienceSortTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0c14970bf481..7e726f3191c6 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -511,6 +511,7 @@
             * [MergeSortRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java)
             * [OddEvenSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/OddEvenSort.java)
             * [PancakeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/PancakeSort.java)
+            * [PatienceSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/PatienceSort.java)
             * [PigeonholeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java)
             * [QuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/QuickSort.java)
             * [RadixSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/RadixSort.java)
@@ -881,6 +882,7 @@
             * [MergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/MergeSortTest.java)
             * [OddEvenSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/OddEvenSortTest.java)
             * [PancakeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java)
+            * [PatienceSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PatienceSortTest.java)
             * [QuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/QuickSortTest.java)
             * [RadixSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/RadixSortTest.java)
             * [SelectionSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java)
diff --git a/src/main/java/com/thealgorithms/sorts/PatienceSort.java b/src/main/java/com/thealgorithms/sorts/PatienceSort.java
new file mode 100644
index 000000000000..52ed30d586b3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/PatienceSort.java
@@ -0,0 +1,112 @@
+package com.thealgorithms.sorts;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.PriorityQueue;
+
+/**
+ * This class implements the Patience Sort algorithm. Patience Sort is a sorting algorithm that
+ * is particularly good for sorting sequences that are already partially sorted.
+ */
+public class PatienceSort implements SortAlgorithm {
+
+    /**
+     * Sorts an array of comparable elements using the Patience Sort algorithm.
+     *
+     * @param array the array to be sorted
+     * @param <T> the type of elements in the array, must be comparable
+     * @return the sorted array
+     */
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array.length == 0) {
+            return array;
+        }
+
+        final List<List<T>> piles = formPiles(array);
+        final PriorityQueue<PileNode<T>> pq = mergePiles(piles);
+        extractPiles(array, pq);
+
+        return array;
+    }
+
+    /**
+     * Forms piles from the given array. Each pile is a list of elements where
+     * each element is smaller than the one before it. Binary search is used
+     * to find the appropriate pile for each element.
+     *
+     * @param array the array of elements to be organized into piles
+     * @param <T> the type of elements in the array, must be comparable
+     * @return a list of piles
+     */
+    private static <T extends Comparable<T>> List<List<T>> formPiles(final T[] array) {
+        final List<List<T>> piles = new ArrayList<>();
+        final List<T> lastElements = new ArrayList<>();
+
+        for (T x : array) {
+            int pos = Collections.binarySearch(lastElements, x);
+            if (pos < 0) {
+                pos = -pos - 1;
+            }
+
+            if (pos < piles.size()) {
+                piles.get(pos).add(x);
+                lastElements.set(pos, x);
+            } else {
+                List<T> newPile = new ArrayList<>();
+                newPile.add(x);
+                piles.add(newPile);
+                lastElements.add(x);
+            }
+        }
+
+        return piles;
+    }
+
+    /**
+     * Merges the piles into a priority queue where the smallest elements are
+     * prioritized.
+     *
+     * @param piles the list of piles to be merged
+     * @param <T> the type of elements in the piles, must be comparable
+     * @return a priority queue containing the top element of each pile
+     */
+    private static <T extends Comparable<T>> PriorityQueue<PileNode<T>> mergePiles(final List<List<T>> piles) {
+        PriorityQueue<PileNode<T>> pq = new PriorityQueue<>();
+        for (List<T> pile : piles) {
+            pq.add(new PileNode<>(pile.removeLast(), pile));
+        }
+        return pq;
+    }
+
+    /**
+     * Extracts elements from the priority queue to form the sorted array.
+     *
+     * @param array the array to be filled with sorted elements
+     * @param pq the priority queue containing the elements to be extracted
+     * @param <T> the type of elements in the array, must be comparable
+     */
+    private static <T extends Comparable<T>> void extractPiles(final T[] array, final PriorityQueue<PileNode<T>> pq) {
+        int index = 0;
+        while (!pq.isEmpty()) {
+            PileNode<T> node = pq.poll();
+            array[index++] = node.value;
+            if (!node.pile.isEmpty()) {
+                pq.add(new PileNode<>(node.pile.removeLast(), node.pile));
+            }
+        }
+    }
+
+    /**
+     * A helper record representing a node in the priority queue.
+     *
+     * @param <T> the type of elements in the node, must be comparable
+     */
+    private record PileNode<T extends Comparable<T>>(T value, List<T> pile) implements Comparable<PileNode<T>> {
+        @Override
+        public int compareTo(PileNode<T> other) {
+            return this.value.compareTo(other.value);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/PatienceSortTest.java b/src/test/java/com/thealgorithms/sorts/PatienceSortTest.java
new file mode 100644
index 000000000000..f3cf7874f3b1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/PatienceSortTest.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.sorts;
+
+public class PatienceSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new PatienceSort();
+    }
+}

From ebed8b38b834b89c1cbccd19fa6bd09b60ff86dc Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 25 Jul 2024 22:55:27 +0300
Subject: [PATCH 0253/1338] refactor: cleanup `PigeonholeSort` (#5298)

* refactor: PigeonholeSort

* checkstyle: fix formatting

* checkstyle: make class final

* refactor: changing negative numbers check first, fix typo, adding one more test for negative numbers

---------

Co-authored-by: Alex Klymenko <alx@alx.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 .../thealgorithms/sorts/PigeonholeSort.java   | 106 ++++++++++++------
 .../sorts/PigeonholeSortTest.java             |  31 +++++
 2 files changed, 101 insertions(+), 36 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/sorts/PigeonholeSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java b/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
index 42fd026b117b..78d7d81d709f 100644
--- a/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
@@ -1,55 +1,89 @@
 package com.thealgorithms.sorts;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 
-public class PigeonholeSort {
+public final class PigeonholeSort {
+    private PigeonholeSort() {
+    }
 
-    /*
-        This code implements the pigeonhole sort algorithm for the integer array,
-        but we can also implement this for string arrays too.
-        See https://www.geeksforgeeks.org/pigeonhole-sort/
-    */
-    void sort(Integer[] array) {
-        int maxElement = array[0];
-        for (int element : array) {
-            if (element > maxElement) {
-                maxElement = element;
-            }
-        }
+    /**
+     * Sorts the given array using the pigeonhole sort algorithm.
+     *
+     * @param array the array to be sorted
+     * @throws IllegalArgumentException if any negative integers are found
+     * @return the sorted array
+     */
+    public static int[] sort(int[] array) {
 
-        int numOfPigeonholes = 1 + maxElement;
-        ArrayList<Integer>[] pigeonHole = new ArrayList[numOfPigeonholes];
+        checkForNegativeInput(array);
 
-        for (int k = 0; k < numOfPigeonholes; k++) {
-            pigeonHole[k] = new ArrayList<>();
+        if (array.length == 0) {
+            return array;
         }
 
-        for (int t : array) {
-            pigeonHole[t].add(t);
-        }
+        final int maxElement = Arrays.stream(array).max().orElseThrow();
+        final List<List<Integer>> pigeonHoles = createPigeonHoles(maxElement);
+
+        populatePigeonHoles(array, pigeonHoles);
+        collectFromPigeonHoles(array, pigeonHoles);
+
+        return array;
+    }
 
-        int k = 0;
-        for (ArrayList<Integer> ph : pigeonHole) {
-            for (int elements : ph) {
-                array[k] = elements;
-                k = k + 1;
+    /**
+     * Checks if the array contains any negative integers.
+     *
+     * @param array the array to be checked
+     * @throws IllegalArgumentException if any negative integers are found
+     */
+    private static void checkForNegativeInput(int[] array) {
+        for (final int number : array) {
+            if (number < 0) {
+                throw new IllegalArgumentException("Array contains negative integers.");
             }
         }
     }
 
-    public static void main(String[] args) {
-        PigeonholeSort pigeonholeSort = new PigeonholeSort();
-        Integer[] arr = {8, 3, 2, 7, 4, 6, 8};
-
-        System.out.print("Unsorted order is : ");
-        SortUtils.print(arr);
+    /**
+     * Creates pigeonholes for sorting using an ArrayList of ArrayLists.
+     *
+     * @param maxElement the maximum element in the array
+     * @return an ArrayList of ArrayLists
+     */
+    private static List<List<Integer>> createPigeonHoles(int maxElement) {
+        List<List<Integer>> pigeonHoles = new ArrayList<>(maxElement + 1);
+        for (int i = 0; i <= maxElement; i++) {
+            pigeonHoles.add(new ArrayList<>());
+        }
+        return pigeonHoles;
+    }
 
-        pigeonholeSort.sort(arr);
+    /**
+     * Populates the pigeonholes with elements from the array.
+     *
+     * @param array the array to be sorted
+     * @param pigeonHoles the pigeonholes to be populated
+     */
+    private static void populatePigeonHoles(int[] array, List<List<Integer>> pigeonHoles) {
+        for (int element : array) {
+            pigeonHoles.get(element).add(element);
+        }
+    }
 
-        System.out.print("Sorted order is : ");
-        for (int i = 0; i < arr.length; i++) {
-            assert (arr[i]) <= (arr[i + 1]);
+    /**
+     * Collects sorted elements from the pigeonholes back into the array.
+     *
+     * @param array the array to be sorted
+     * @param pigeonHoles the populated pigeonholes
+     */
+    private static void collectFromPigeonHoles(int[] array, List<List<Integer>> pigeonHoles) {
+        int index = 0;
+        for (final var pigeonHole : pigeonHoles) {
+            for (final int element : pigeonHole) {
+                array[index++] = element;
+            }
         }
-        SortUtils.print(arr);
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/PigeonholeSortTest.java b/src/test/java/com/thealgorithms/sorts/PigeonholeSortTest.java
new file mode 100644
index 000000000000..d1772de83701
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/PigeonholeSortTest.java
@@ -0,0 +1,31 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class PigeonholeSortTest {
+
+    @ParameterizedTest
+    @MethodSource("provideArraysForPigeonholeSort")
+    public void testPigeonholeSort(int[] inputArray, int[] expectedArray) {
+        PigeonholeSort.sort(inputArray);
+        assertArrayEquals(expectedArray, inputArray);
+    }
+
+    private static Stream<Arguments> provideArraysForPigeonholeSort() {
+        return Stream.of(Arguments.of(new int[] {}, new int[] {}), Arguments.of(new int[] {4}, new int[] {4}), Arguments.of(new int[] {6, 1, 99, 27, 15, 23, 36}, new int[] {1, 6, 15, 23, 27, 36, 99}), Arguments.of(new int[] {6, 1, 27, 15, 23, 27, 36, 23}, new int[] {1, 6, 15, 23, 23, 27, 27, 36}),
+            Arguments.of(new int[] {5, 5, 5, 5, 5}, new int[] {5, 5, 5, 5, 5}), Arguments.of(new int[] {1, 2, 3, 4, 5}, new int[] {1, 2, 3, 4, 5}), Arguments.of(new int[] {5, 4, 3, 2, 1}, new int[] {1, 2, 3, 4, 5}));
+    }
+
+    @Test
+    public void testWithNegativeNumbers() {
+        assertThrows(IllegalArgumentException.class, () -> PigeonholeSort.sort(new int[] {3, 1, 4, 1, 5, -9}));
+        assertThrows(IllegalArgumentException.class, () -> PigeonholeSort.sort(new int[] {-1}));
+    }
+}

From 5113101e5dd4eb2d74a8c9f5e15b73773b974bb5 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 26 Jul 2024 09:55:11 +0300
Subject: [PATCH 0254/1338] refactor: cleanup `ShellSort` (#5302)

---
 .../com/thealgorithms/sorts/ShellSort.java    | 69 ++++++++++++-------
 .../thealgorithms/sorts/ShellSortTest.java    | 66 ++----------------
 2 files changed, 50 insertions(+), 85 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/ShellSort.java b/src/main/java/com/thealgorithms/sorts/ShellSort.java
index 37a50e855698..d12b181e65a2 100644
--- a/src/main/java/com/thealgorithms/sorts/ShellSort.java
+++ b/src/main/java/com/thealgorithms/sorts/ShellSort.java
@@ -11,36 +11,59 @@ public class ShellSort implements SortAlgorithm {
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
-        int length = array.length;
-        int gap = 1;
-
-        /* Calculate gap for optimization purpose */
-        while (gap < length / 3) {
-            gap = 3 * gap + 1;
+        if (array.length == 0) {
+            return array;
         }
 
-        for (; gap > 0; gap /= 3) {
-            for (int i = gap; i < length; i++) {
-                int j;
-                T temp = array[i];
-                for (j = i; j >= gap && SortUtils.less(temp, array[j - gap]); j -= gap) {
-                    array[j] = array[j - gap];
-                }
-                array[j] = temp;
-            }
+        int gap = calculateInitialGap(array.length);
+
+        while (gap > 0) {
+            performGapInsertionSort(array, gap);
+            gap = calculateNextGap(gap);
         }
+
         return array;
     }
 
-    /* Driver Code */
-    public static void main(String[] args) {
-        Integer[] toSort = {4, 23, 6, 78, 1, 54, 231, 9, 12};
+    /**
+     * Calculates the initial gap value using the Knuth sequence.
+     *
+     * @param length the length of the array.
+     * @return the initial gap value.
+     */
+    private int calculateInitialGap(final int length) {
+        int gap = 1;
+        while (gap < length / 3) {
+            gap = 3 * gap + 1;
+        }
+        return gap;
+    }
+
+    /**
+     * Calculates the next gap value.
+     *
+     * @param currentGap the current gap value.
+     * @return the next gap value.
+     */
+    private int calculateNextGap(final int currentGap) {
+        return currentGap / 3;
+    }
 
-        ShellSort sort = new ShellSort();
-        sort.sort(toSort);
-        for (int i = 0; i < toSort.length - 1; ++i) {
-            assert toSort[i] <= toSort[i + 1];
+    /**
+     * Performs an insertion sort for the specified gap value.
+     *
+     * @param array the array to be sorted.
+     * @param gap the current gap value.
+     * @param <T> the type of elements in the array.
+     */
+    private <T extends Comparable<T>> void performGapInsertionSort(final T[] array, final int gap) {
+        for (int i = gap; i < array.length; i++) {
+            T temp = array[i];
+            int j;
+            for (j = i; j >= gap && SortUtils.less(temp, array[j - gap]); j -= gap) {
+                array[j] = array[j - gap];
+            }
+            array[j] = temp;
         }
-        SortUtils.print(toSort);
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/ShellSortTest.java b/src/test/java/com/thealgorithms/sorts/ShellSortTest.java
index 73be91b397bd..b41f2c2e863b 100644
--- a/src/test/java/com/thealgorithms/sorts/ShellSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/ShellSortTest.java
@@ -1,66 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-
-import org.junit.jupiter.api.Test;
-
-public class ShellSortTest {
-
-    private ShellSort shellSort = new ShellSort();
-
-    @Test
-    public void shellSortEmptyArray() {
-        Integer[] inputArray = {};
-        Integer[] outputArray = shellSort.sort(inputArray);
-        Integer[] expectedOutput = {};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void shellSortSingleIntegerArray() {
-        Integer[] inputArray = {4};
-        Integer[] outputArray = shellSort.sort(inputArray);
-        Integer[] expectedOutput = {4};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void shellSortSingleStringArray() {
-        String[] inputArray = {"s"};
-        String[] outputArray = shellSort.sort(inputArray);
-        String[] expectedOutput = {"s"};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void shellSortNonDuplicateIntegerArray() {
-        Integer[] inputArray = {6, -1, 99, 27, -15, 23, -36};
-        Integer[] outputArray = shellSort.sort(inputArray);
-        Integer[] expectedOutput = {-36, -15, -1, 6, 23, 27, 99};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void shellSortDuplicateIntegerArray() {
-        Integer[] inputArray = {6, -1, 27, -15, 23, 27, -36, 23};
-        Integer[] outputArray = shellSort.sort(inputArray);
-        Integer[] expectedOutput = {-36, -15, -1, 6, 23, 23, 27, 27};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void shellSortNonDuplicateStringArray() {
-        String[] inputArray = {"s", "b", "k", "a", "d", "c", "h"};
-        String[] outputArray = shellSort.sort(inputArray);
-        String[] expectedOutput = {"a", "b", "c", "d", "h", "k", "s"};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void shellSortDuplicateStringArray() {
-        String[] inputArray = {"s", "b", "d", "a", "d", "c", "h", "b"};
-        String[] outputArray = shellSort.sort(inputArray);
-        String[] expectedOutput = {"a", "b", "b", "c", "d", "d", "h", "s"};
-        assertArrayEquals(outputArray, expectedOutput);
+public class ShellSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new ShellSort();
     }
 }

From fccd1410148a9bdda0d6cf2ddbf5ec10927c6260 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 2 Aug 2024 09:06:45 +0200
Subject: [PATCH 0255/1338] refactor: cleanup `CombSort` (#5303)

refactor: cleanup CombSort

Co-authored-by: Alex Klymenko <alx@alx.com>
---
 .../com/thealgorithms/sorts/CombSort.java     | 89 ++++++++-----------
 .../com/thealgorithms/sorts/CombSortTest.java | 66 +-------------
 2 files changed, 39 insertions(+), 116 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/CombSort.java b/src/main/java/com/thealgorithms/sorts/CombSort.java
index edf09a2eb3f8..cd12a5b2853c 100644
--- a/src/main/java/com/thealgorithms/sorts/CombSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CombSort.java
@@ -16,76 +16,57 @@
  * @see SortAlgorithm
  */
 class CombSort implements SortAlgorithm {
+    private static final double SHRINK_FACTOR = 1.3;
 
-    // To find gap between elements
-    private int nextGap(int gap) {
-        // Shrink gap by Shrink factor
-        gap = (gap * 10) / 13;
+    /**
+     * Method to find the next gap
+     *
+     * @param gap the current gap
+     * @return the next gap value
+     */
+    private int getNextGap(int gap) {
+        gap = (int) (gap / SHRINK_FACTOR);
         return Math.max(gap, 1);
     }
 
     /**
-     * Function to sort arr[] using Comb
+     * Method to sort the array using CombSort
      *
-     * @param arr - an array should be sorted
-     * @return sorted array
+     * @param arr the array to be sorted
+     * @param <T> the type of elements in the array
+     * @return the sorted array
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] arr) {
-        int size = arr.length;
-
-        // initialize gap
-        int gap = size;
-
-        // Initialize swapped as true to make sure that loop runs
+        int gap = arr.length;
         boolean swapped = true;
 
-        // Keep running while gap is more than 1 and last iteration caused a swap
         while (gap != 1 || swapped) {
-            // Find next gap
-            gap = nextGap(gap);
-
-            // Initialize swapped as false so that we can check if swap happened or not
-            swapped = false;
-
-            // Compare all elements with current gap
-            for (int i = 0; i < size - gap; i++) {
-                if (SortUtils.less(arr[i + gap], arr[i])) {
-                    // Swap arr[i] and arr[i+gap]
-                    SortUtils.swap(arr, i, i + gap);
-                    swapped = true;
-                }
-            }
+            gap = getNextGap(gap);
+            swapped = performSwaps(arr, gap);
         }
+
         return arr;
     }
 
-    // Driver method
-    public static void main(String[] args) {
-        CombSort ob = new CombSort();
-        Integer[] arr = {
-            8,
-            4,
-            1,
-            56,
-            3,
-            -44,
-            -1,
-            0,
-            36,
-            34,
-            8,
-            12,
-            -66,
-            -78,
-            23,
-            -6,
-            28,
-            0,
-        };
-        ob.sort(arr);
+    /**
+     * Method to perform the swapping of elements in the array based on the current gap
+     *
+     * @param arr the array to be sorted
+     * @param gap the current gap
+     * @param <T> the type of elements in the array
+     * @return true if a swap occurred, false otherwise
+     */
+    private <T extends Comparable<T>> boolean performSwaps(final T[] arr, final int gap) {
+        boolean swapped = false;
+
+        for (int i = 0; i < arr.length - gap; i++) {
+            if (SortUtils.less(arr[i + gap], arr[i])) {
+                SortUtils.swap(arr, i, i + gap);
+                swapped = true;
+            }
+        }
 
-        System.out.println("sorted array");
-        SortUtils.print(arr);
+        return swapped;
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/CombSortTest.java b/src/test/java/com/thealgorithms/sorts/CombSortTest.java
index e33fc388c1c5..6b70ffacda47 100644
--- a/src/test/java/com/thealgorithms/sorts/CombSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/CombSortTest.java
@@ -1,66 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-
-import org.junit.jupiter.api.Test;
-
-/**
- * @author Tabbygray (https://github.com/Tabbygray)
- * @see CombSort
- */
-
-public class CombSortTest {
-
-    private CombSort combSort = new CombSort();
-
-    @Test
-    public void combSortEmptyArray() {
-        Integer[] inputArray = {};
-        Integer[] outputArray = combSort.sort(inputArray);
-        Integer[] expectedOutput = {};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void combSortSingleStringElement() {
-        String[] inputArray = {"Test"};
-        String[] outputArray = combSort.sort(inputArray);
-        String[] expectedArray = {"Test"};
-        assertArrayEquals(outputArray, expectedArray);
-    }
-
-    @Test
-    public void combSortStringArray() {
-        String[] inputArray = {"4gp8", "aBJ2", "85cW", "Pmk9", "ewZO", "meuU", "RhNd", "5TKB", "eDd5", "zzyo"};
-        String[] outputArray = combSort.sort(inputArray);
-        String[] expectedArray = {"4gp8", "5TKB", "85cW", "Pmk9", "RhNd", "aBJ2", "eDd5", "ewZO", "meuU", "zzyo"};
-        assertArrayEquals(outputArray, expectedArray);
-    }
-
-    @Test
-    public void combSortIntegerArray() {
-        Integer[] inputArray = {36, 98, -51, -23, 66, -58, 31, 25, -30, 40};
-        Integer[] outputArray = combSort.sort(inputArray);
-        Integer[] expectedArray = {-58, -51, -30, -23, 25, 31, 36, 40, 66, 98};
-        assertArrayEquals(outputArray, expectedArray);
-    }
-
-    @Test
-    public void combSortDoubleArray() {
-        Double[] inputArray = {0.8335545399, 0.9346214114, 0.3096396752, 0.6433840668, 0.3973191975, 0.6118850724, 0.0553975453, 0.1961108601, 0.6172800885, 0.1065247772};
-        Double[] outputArray = combSort.sort(inputArray);
-        Double[] expectedArray = {
-            0.0553975453,
-            0.1065247772,
-            0.1961108601,
-            0.3096396752,
-            0.3973191975,
-            0.6118850724,
-            0.6172800885,
-            0.6433840668,
-            0.8335545399,
-            0.9346214114,
-        };
-        assertArrayEquals(outputArray, expectedArray);
+public class CombSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new CombSort();
     }
 }

From 6f521145cce64822ac31331a33e48a9a748670c9 Mon Sep 17 00:00:00 2001
From: Bayram Turgut <137455737+bayramtturgutt@users.noreply.github.com>
Date: Sun, 4 Aug 2024 21:15:54 +0300
Subject: [PATCH 0256/1338] Update Average.java (#5309)

* Update Average.java

- Made the constructor throw an UnsupportedOperationException to prevent instantiation, making it explicit that this is a utility class.
- Added a private validateInput method to handle validation, reducing code duplication and improving readability.
- Consistent exception messages and handling for both methods.
- Improved comments to be more descriptive and follow JavaDoc conventions.
- Enhanced code readability and maintained consistent formatting.

* Minor Update Average.java

* Change To Average.java

* Mnr Average.java

* Update_Average.java

* Fix Average.java

1. throw new IllegalArgumentException("Numbers array cannot be empty or null");

2. int --> double

* fix2.java

return(double)..
---
 .../java/com/thealgorithms/maths/Average.java | 26 ++++++++++++-------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Average.java b/src/main/java/com/thealgorithms/maths/Average.java
index 1c632cf0a65e..6b9c20162da1 100644
--- a/src/main/java/com/thealgorithms/maths/Average.java
+++ b/src/main/java/com/thealgorithms/maths/Average.java
@@ -1,17 +1,23 @@
 package com.thealgorithms.maths;
 
 /**
- * Calculate average of a list of numbers
+ * A utility class for computing the average of numeric arrays.
+ * This class provides static methods to calculate the average of arrays
+ * of both {@code double} and {@code int} values.
  */
 public final class Average {
+
+    // Prevent instantiation of this utility class
     private Average() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated.");
     }
 
     /**
-     * Calculate average of a list of numbers
+     * Computes the average of a {@code double} array.
      *
-     * @param numbers array to store numbers
-     * @return mean of given numbers
+     * @param numbers an array of {@code double} values
+     * @return the average of the given numbers
+     * @throws IllegalArgumentException if the input array is {@code null} or empty
      */
     public static double average(double[] numbers) {
         if (numbers == null || numbers.length == 0) {
@@ -25,13 +31,13 @@ public static double average(double[] numbers) {
     }
 
     /**
-     * find average value of an int array
+     * Computes the average of an {@code int} array.
      *
-     * @param numbers the array contains element and the sum does not excess long
-     *                value limit
-     * @return average value
+     * @param numbers an array of {@code int} values
+     * @return the average of the given numbers
+     * @throws IllegalArgumentException if the input array is {@code null} or empty
      */
-    public static int average(int[] numbers) {
+    public static double average(int[] numbers) {
         if (numbers == null || numbers.length == 0) {
             throw new IllegalArgumentException("Numbers array cannot be empty or null");
         }
@@ -39,6 +45,6 @@ public static int average(int[] numbers) {
         for (int number : numbers) {
             sum += number;
         }
-        return (int) (sum / numbers.length);
+        return (double) (sum / numbers.length);
     }
 }

From 365ede892f2a44ed11421887c06b65cd7a182cb3 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 8 Aug 2024 07:38:58 +0200
Subject: [PATCH 0257/1338] Chore(deps): bump org.apache.commons:commons-lang3
 from 3.15.0 to 3.16.0 (#5312)

Bumps org.apache.commons:commons-lang3 from 3.15.0 to 3.16.0.

---
updated-dependencies:
- dependency-name: org.apache.commons:commons-lang3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 0c01353aa5dd..0c69e1f50732 100644
--- a/pom.xml
+++ b/pom.xml
@@ -50,7 +50,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
-            <version>3.15.0</version>
+            <version>3.16.0</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>

From 357e15adddd1c268909299345ca50bb63c1a982c Mon Sep 17 00:00:00 2001
From: Andrii Siriak <siryaka@gmail.com>
Date: Thu, 8 Aug 2024 09:55:11 +0300
Subject: [PATCH 0258/1338] Update CODEOWNERS

---
 .github/CODEOWNERS | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index a84f13be1047..4f36c32c5157 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1 +1 @@
-* @yanglbme @vil02 @BamaCharanChhandogi
+* @yanglbme @vil02 @BamaCharanChhandogi @alxkm

From 6e23e198ab30bbba5cdbf74d5282f98080083f3d Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 8 Aug 2024 09:45:33 +0200
Subject: [PATCH 0259/1338] feat: `SpreadSort` implementation (#5308)

---
 DIRECTORY.md                                  |   2 +
 .../com/thealgorithms/sorts/SpreadSort.java   | 273 ++++++++++++++++++
 .../thealgorithms/sorts/SpreadSortTest.java   |  37 +++
 3 files changed, 312 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/SpreadSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/SpreadSortTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7e726f3191c6..22453235bfed 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -523,6 +523,7 @@
             * [SortAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SortAlgorithm.java)
             * [SortUtils](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SortUtils.java)
             * [SortUtilsRandomGenerator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java)
+            * [SpreadSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SpreadSort.java)
             * [StoogeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/StoogeSort.java)
             * [StrandSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/StrandSort.java)
             * [SwapSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SwapSort.java)
@@ -893,6 +894,7 @@
             * [SortingAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java)
             * [SortUtilsRandomGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortUtilsRandomGeneratorTest.java)
             * [SortUtilsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java)
+            * [SpreadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SpreadSortTest.java)
             * [StoogeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StoogeSortTest.java)
             * [StrandSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StrandSortTest.java)
             * [SwapSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SwapSortTest.java)
diff --git a/src/main/java/com/thealgorithms/sorts/SpreadSort.java b/src/main/java/com/thealgorithms/sorts/SpreadSort.java
new file mode 100644
index 000000000000..f1fd24f4735d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/SpreadSort.java
@@ -0,0 +1,273 @@
+package com.thealgorithms.sorts;
+import java.util.Arrays;
+
+/**
+ * SpreadSort is a highly efficient sorting algorithm suitable for large datasets.
+ * It distributes elements into buckets and recursively sorts these buckets.
+ * This implementation is generic and can sort any array of elements that extend Comparable.
+ */
+public class SpreadSort implements SortAlgorithm {
+    private static final int MAX_INSERTION_SORT_THRESHOLD = 1000;
+    private static final int MAX_INITIAL_BUCKET_CAPACITY = 1000;
+    private static final int MAX_MIN_BUCKETS = 100;
+
+    private final int insertionSortThreshold;
+    private final int initialBucketCapacity;
+    private final int minBuckets;
+
+    /**
+     * Constructor to initialize the SpreadSort algorithm with custom parameters.
+     *
+     * @param insertionSortThreshold the threshold for using insertion sort for small segments (1-1000)
+     * @param initialBucketCapacity  the initial capacity for each bucket (1-1000)
+     * @param minBuckets             the minimum number of buckets to use (1-100)
+     */
+    public SpreadSort(int insertionSortThreshold, int initialBucketCapacity, int minBuckets) {
+        if (insertionSortThreshold < 1 || insertionSortThreshold > MAX_INSERTION_SORT_THRESHOLD) {
+            throw new IllegalArgumentException("Insertion sort threshold must be between 1 and " + MAX_INSERTION_SORT_THRESHOLD);
+        }
+        if (initialBucketCapacity < 1 || initialBucketCapacity > MAX_INITIAL_BUCKET_CAPACITY) {
+            throw new IllegalArgumentException("Initial bucket capacity must be between 1 and " + MAX_INITIAL_BUCKET_CAPACITY);
+        }
+        if (minBuckets < 1 || minBuckets > MAX_MIN_BUCKETS) {
+            throw new IllegalArgumentException("Minimum number of buckets must be between 1 and " + MAX_MIN_BUCKETS);
+        }
+
+        this.insertionSortThreshold = insertionSortThreshold;
+        this.initialBucketCapacity = initialBucketCapacity;
+        this.minBuckets = minBuckets;
+    }
+
+    /**
+     * Default constructor with predefined values.
+     */
+    public SpreadSort() {
+        this(16, 16, 2);
+    }
+
+    /**
+     * Sorts an array using the SpreadSort algorithm.
+     *
+     * @param array the array to be sorted
+     * @param <T>   the type of elements in the array
+     * @return the sorted array
+     */
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array.length == 0) {
+            return array;
+        }
+        spreadSort(array, 0, array.length - 1);
+        return array;
+    }
+
+    /**
+     * Internal method to sort an array segment using the SpreadSort algorithm.
+     *
+     * @param array the array to be sorted
+     * @param left  the left boundary of the segment
+     * @param right the right boundary of the segment
+     * @param <T>   the type of elements in the array
+     */
+    private <T extends Comparable<T>> void spreadSort(final T[] array, final int left, final int right) {
+        if (left >= right) {
+            return;
+        }
+
+        // Base case for small segments
+        if (right - left < insertionSortThreshold) {
+            insertionSort(array, left, right);
+            return;
+        }
+
+        T min = findMin(array, left, right);
+        T max = findMax(array, left, right);
+
+        if (min.equals(max)) {
+            return; // All elements are the same
+        }
+
+        int numBuckets = calculateNumBuckets(right - left + 1);
+        final Bucket<T>[] buckets = createBuckets(numBuckets);
+
+        distributeElements(array, left, right, min, max, numBuckets, buckets);
+        collectElements(array, left, buckets);
+    }
+
+    /**
+     * Finds the minimum element in the specified segment of the array.
+     *
+     * @param array the array to search
+     * @param left  the left boundary of the segment
+     * @param right the right boundary of the segment
+     * @param <T>   the type of elements in the array
+     * @return the minimum element
+     */
+    private <T extends Comparable<T>> T findMin(final T[] array, final int left, final int right) {
+        T min = array[left];
+        for (int i = left + 1; i <= right; i++) {
+            if (SortUtils.less(array[i], min)) {
+                min = array[i];
+            }
+        }
+        return min;
+    }
+
+    /**
+     * Finds the maximum element in the specified segment of the array.
+     *
+     * @param array the array to search
+     * @param left  the left boundary of the segment
+     * @param right the right boundary of the segment
+     * @param <T>   the type of elements in the array
+     * @return the maximum element
+     */
+    private <T extends Comparable<T>> T findMax(final T[] array, final int left, final int right) {
+        T max = array[left];
+        for (int i = left + 1; i <= right; i++) {
+            if (SortUtils.greater(array[i], max)) {
+                max = array[i];
+            }
+        }
+        return max;
+    }
+
+    /**
+     * Calculates the number of buckets needed based on the size of the segment.
+     *
+     * @param segmentSize the size of the segment
+     * @return the number of buckets
+     */
+    private int calculateNumBuckets(final int segmentSize) {
+        int numBuckets = segmentSize / insertionSortThreshold;
+        return Math.max(numBuckets, minBuckets);
+    }
+
+    /**
+     * Creates an array of buckets.
+     *
+     * @param numBuckets the number of buckets to create
+     * @param <T>        the type of elements in the buckets
+     * @return an array of buckets
+     */
+    @SuppressWarnings("unchecked")
+    private <T extends Comparable<T>> Bucket<T>[] createBuckets(final int numBuckets) {
+        final Bucket<T>[] buckets = new Bucket[numBuckets];
+        for (int i = 0; i < numBuckets; i++) {
+            buckets[i] = new Bucket<>(initialBucketCapacity);
+        }
+        return buckets;
+    }
+
+    /**
+     * Distributes elements of the array segment into buckets.
+     *
+     * @param array      the array to be sorted
+     * @param left       the left boundary of the segment
+     * @param right      the right boundary of the segment
+     * @param min        the minimum element in the segment
+     * @param max        the maximum element in the segment
+     * @param numBuckets the number of buckets
+     * @param buckets    the array of buckets
+     * @param <T>        the type of elements in the array
+     */
+    private <T extends Comparable<T>> void distributeElements(final T[] array, final int left, final int right, final T min, final T max, final int numBuckets, final Bucket<T>[] buckets) {
+        final double range = max.compareTo(min);
+        for (int i = left; i <= right; i++) {
+            final int scaleRangeDifference = array[i].compareTo(min) * numBuckets;
+            int bucketIndex = (int) (scaleRangeDifference / (range + 1));
+            buckets[bucketIndex].add(array[i]);
+        }
+    }
+
+    /**
+     * Collects elements from the buckets back into the array.
+     *
+     * @param array   the array to be sorted
+     * @param left    the left boundary of the segment
+     * @param buckets the array of buckets
+     * @param <T>     the type of elements in the array
+     */
+    private <T extends Comparable<T>> void collectElements(final T[] array, final int left, final Bucket<T>[] buckets) {
+        int index = left;
+        for (Bucket<T> bucket : buckets) {
+            if (bucket.size() > 0) {
+                T[] bucketArray = bucket.toArray();
+                spreadSort(bucketArray, 0, bucketArray.length - 1);
+                for (T element : bucketArray) {
+                    array[index++] = element;
+                }
+            }
+        }
+    }
+
+    /**
+     * Insertion sort implementation for small segments.
+     *
+     * @param array the array to be sorted
+     * @param left  the left boundary of the segment
+     * @param right the right boundary of the segment
+     * @param <T>   the type of elements in the array
+     */
+    private <T extends Comparable<T>> void insertionSort(final T[] array, final int left, final int right) {
+        for (int i = left + 1; i <= right; i++) {
+            T key = array[i];
+            int j = i - 1;
+            while (j >= left && SortUtils.greater(array[j], key)) {
+                array[j + 1] = array[j];
+                j--;
+            }
+            array[j + 1] = key;
+        }
+    }
+
+    /**
+     * Bucket class to hold elements during sorting.
+     *
+     * @param <T> the type of elements in the bucket
+     */
+    private static class Bucket<T extends Comparable<T>> {
+        private T[] elements;
+        private int size;
+
+        /**
+         * Constructs a new bucket with initial capacity.
+         */
+        @SuppressWarnings("unchecked")
+        Bucket(int initialBucketCapacity) {
+            elements = (T[]) new Comparable[initialBucketCapacity];
+            size = 0;
+        }
+
+        /**
+         * Adds an element to the bucket.
+         *
+         * @param element the element to add
+         */
+        void add(T element) {
+            if (size == elements.length) {
+                elements = Arrays.copyOf(elements, size * 2);
+            }
+            elements[size++] = element;
+        }
+
+        /**
+         * Returns the number of elements in the bucket.
+         *
+         * @return the size of the bucket
+         */
+        int size() {
+            return size;
+        }
+
+        /**
+         * Returns an array containing all elements in the bucket.
+         *
+         * @return an array containing all elements in the bucket
+         */
+        @SuppressWarnings("unchecked")
+        T[] toArray() {
+            return Arrays.copyOf(elements, size);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/SpreadSortTest.java b/src/test/java/com/thealgorithms/sorts/SpreadSortTest.java
new file mode 100644
index 000000000000..a4992a02abfa
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/SpreadSortTest.java
@@ -0,0 +1,37 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.function.Executable;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.ArgumentsProvider;
+import org.junit.jupiter.params.provider.ArgumentsSource;
+
+public class SpreadSortTest extends SortingAlgorithmTest {
+
+    protected int getGeneratedArraySize() {
+        return 1000;
+    }
+
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new SpreadSort();
+    }
+
+    static class ConstructorArgumentsProvider implements ArgumentsProvider {
+        @Override
+        public Stream<? extends Arguments> provideArguments(org.junit.jupiter.api.extension.ExtensionContext context) {
+            return Stream.of(Arguments.of(0, 16, 2, IllegalArgumentException.class), Arguments.of(16, 0, 2, IllegalArgumentException.class), Arguments.of(16, 16, 0, IllegalArgumentException.class), Arguments.of(1001, 16, 2, IllegalArgumentException.class),
+                Arguments.of(16, 1001, 2, IllegalArgumentException.class), Arguments.of(16, 16, 101, IllegalArgumentException.class));
+        }
+    }
+
+    @ParameterizedTest
+    @ArgumentsSource(ConstructorArgumentsProvider.class)
+    void testConstructor(int insertionSortThreshold, int initialBucketCapacity, int minBuckets, Class<Exception> expectedException) {
+        Executable executable = () -> new SpreadSort(insertionSortThreshold, initialBucketCapacity, minBuckets);
+        assertThrows(expectedException, executable);
+    }
+}

From cafea1ee528bde4495024d7c8db177e9474e5e36 Mon Sep 17 00:00:00 2001
From: congyuluo <78986434+congyuluo@users.noreply.github.com>
Date: Thu, 8 Aug 2024 07:09:00 -0700
Subject: [PATCH 0260/1338] Refactored Identifiers (#5306)

Co-authored-by: Bama Charan Chhandogi <b.c.chhandogi@gmail.com>
---
 .../java/com/thealgorithms/misc/TwoSumProblem.java     |  6 +++---
 .../com/thealgorithms/searches/FibonacciSearch.java    |  6 +++---
 .../java/com/thealgorithms/strings/WordLadder.java     | 10 +++++-----
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/thealgorithms/misc/TwoSumProblem.java b/src/main/java/com/thealgorithms/misc/TwoSumProblem.java
index ceeb3717fd4a..2fc4ed09a792 100644
--- a/src/main/java/com/thealgorithms/misc/TwoSumProblem.java
+++ b/src/main/java/com/thealgorithms/misc/TwoSumProblem.java
@@ -20,9 +20,9 @@ private TwoSumProblem() {
     public static Optional<Pair<Integer, Integer>> twoSum(final int[] values, final int target) {
         HashMap<Integer, Integer> valueToIndex = new HashMap<>();
         for (int i = 0; i < values.length; i++) {
-            final var rem = target - values[i];
-            if (valueToIndex.containsKey(rem)) {
-                return Optional.of(Pair.of(valueToIndex.get(rem), i));
+            final var remainder = target - values[i];
+            if (valueToIndex.containsKey(remainder)) {
+                return Optional.of(Pair.of(valueToIndex.get(remainder), i));
             }
             if (!valueToIndex.containsKey(values[i])) {
                 valueToIndex.put(values[i], i);
diff --git a/src/main/java/com/thealgorithms/searches/FibonacciSearch.java b/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
index 4fba6e257627..028ab07e0a86 100644
--- a/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
+++ b/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
@@ -62,10 +62,10 @@ public static void main(String[] args) {
         Integer[] integers = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512};
 
         int size = integers.length;
-        Integer shouldBeFound = 128;
+        Integer targetValue = 128;
         FibonacciSearch fsearch = new FibonacciSearch();
-        int atIndex = fsearch.find(integers, shouldBeFound);
+        int atIndex = fsearch.find(integers, targetValue);
 
-        System.out.println("Should be found: " + shouldBeFound + ". Found " + integers[atIndex] + " at index " + atIndex + ". An array length " + size);
+        System.out.println("Should be found: " + targetValue + ". Found " + integers[atIndex] + " at index " + atIndex + ". An array length " + size);
     }
 }
diff --git a/src/main/java/com/thealgorithms/strings/WordLadder.java b/src/main/java/com/thealgorithms/strings/WordLadder.java
index 16d4e0a02452..707fdfc67d85 100644
--- a/src/main/java/com/thealgorithms/strings/WordLadder.java
+++ b/src/main/java/com/thealgorithms/strings/WordLadder.java
@@ -75,13 +75,13 @@ public static int ladderLength(String beginWord, String endWord, List<String> wo
                             continue;
                         }
                         wordsChars[j] = c;
-                        String newWord = String.valueOf(wordsChars);
-                        if (newWord.equals(endWord)) {
+                        String transformedWord = String.valueOf(wordsChars);
+                        if (transformedWord.equals(endWord)) {
                             return level + 1;
                         }
-                        if (set.contains(newWord)) {
-                            set.remove(newWord);
-                            queue.offer(newWord);
+                        if (set.contains(transformedWord)) {
+                            set.remove(transformedWord);
+                            queue.offer(transformedWord);
                         }
                     }
                     wordsChars[j] = originalChars;

From 5fc26239eb2b6d93e582a8df30027d2ef3da392d Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 9 Aug 2024 07:42:26 +0200
Subject: [PATCH 0261/1338] Chore(deps): bump DoozyX/clang-format-lint-action
 from 0.17 to 0.18 in /.github/workflows (#5313)

Chore(deps): bump DoozyX/clang-format-lint-action in /.github/workflows

Bumps [DoozyX/clang-format-lint-action](https://github.com/doozyx/clang-format-lint-action) from 0.17 to 0.18.
- [Release notes](https://github.com/doozyx/clang-format-lint-action/releases)
- [Commits](https://github.com/doozyx/clang-format-lint-action/compare/v0.17...v0.18)

---
updated-dependencies:
- dependency-name: DoozyX/clang-format-lint-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/clang-format-lint.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/clang-format-lint.yml b/.github/workflows/clang-format-lint.yml
index 7f3cb3d5162f..588c05e42e8f 100644
--- a/.github/workflows/clang-format-lint.yml
+++ b/.github/workflows/clang-format-lint.yml
@@ -9,7 +9,7 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-    - uses: DoozyX/clang-format-lint-action@v0.17
+    - uses: DoozyX/clang-format-lint-action@v0.18
       with:
         source: './src'
         extensions: 'java'

From 324a35a939e86eda64af74aad37c2d8536caed7f Mon Sep 17 00:00:00 2001
From: Bayram Turgut <137455737+bayramtturgutt@users.noreply.github.com>
Date: Fri, 9 Aug 2024 15:03:54 +0300
Subject: [PATCH 0262/1338] Update GrahamScan.java (#5310)

* Update GrahamScan.java

improved the Javadoc comments, clarified some methods in the Point class, and corrected some text.

* Minor adjustment to GrahamScan.java

* revised GrahamScan.java

* Update-2 GrahamScan.java

* clang format GrahamScan.java

* reverted GrahamScan.java

* minor updates.java

* minor updates

* Spc.java

* clang format

---------

Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 .../thealgorithms/geometry/GrahamScan.java    | 117 ++++++++----------
 1 file changed, 49 insertions(+), 68 deletions(-)

diff --git a/src/main/java/com/thealgorithms/geometry/GrahamScan.java b/src/main/java/com/thealgorithms/geometry/GrahamScan.java
index 2773d03b4769..1a36137895e0 100644
--- a/src/main/java/com/thealgorithms/geometry/GrahamScan.java
+++ b/src/main/java/com/thealgorithms/geometry/GrahamScan.java
@@ -1,56 +1,56 @@
 package com.thealgorithms.geometry;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
 import java.util.Stack;
 
-/*
- * A Java program that computes the convex hull using the Graham Scan algorithm
- * In the best case, time complexity is O(n), while in the worst case, it is O(nlog(n)).
- * O(n) space complexity
+/**
+ * A Java program that computes the convex hull using the Graham Scan algorithm.
+ * The time complexity is O(n) in the best case and O(n log(n)) in the worst case.
+ * The space complexity is O(n).
+ * This algorithm is applicable only to integral coordinates.
  *
- * This algorithm is only applicable to integral coordinates.
- *
- * Reference:
+ * References:
  * https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/geometry/graham_scan_algorithm.cpp
  * https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/geometry/graham_scan_functions.hpp
  * https://algs4.cs.princeton.edu/99hull/GrahamScan.java.html
  */
 public class GrahamScan {
+
     private final Stack<Point> hull = new Stack<>();
 
     public GrahamScan(Point[] points) {
-
-        /*
-         * pre-process the points by sorting them with respect to the bottom-most point, then we'll
-         * push the first point in the array to be our first extreme point.
-         */
+        // Pre-process points: sort by y-coordinate, then by polar order with respect to the first point
         Arrays.sort(points);
         Arrays.sort(points, 1, points.length, points[0].polarOrder());
+
         hull.push(points[0]);
 
-        // find index of first point not equal to a[0] (indexPoint1) and the first point that's not
-        // collinear with either (indexPoint2).
-        int indexPoint1;
-        for (indexPoint1 = 1; indexPoint1 < points.length; indexPoint1++) {
-            if (!points[0].equals(points[indexPoint1])) {
+        // Find the first point not equal to points[0] (firstNonEqualIndex)
+        // and the first point not collinear firstNonCollinearIndex with the previous points
+        int firstNonEqualIndex;
+        for (firstNonEqualIndex = 1; firstNonEqualIndex < points.length; firstNonEqualIndex++) {
+            if (!points[0].equals(points[firstNonEqualIndex])) {
                 break;
             }
         }
-        if (indexPoint1 == points.length) {
+
+        if (firstNonEqualIndex == points.length) {
             return;
         }
 
-        int indexPoint2;
-        for (indexPoint2 = indexPoint1 + 1; indexPoint2 < points.length; indexPoint2++) {
-            if (Point.orientation(points[0], points[indexPoint1], points[indexPoint2]) != 0) {
+        int firstNonCollinearIndex;
+        for (firstNonCollinearIndex = firstNonEqualIndex + 1; firstNonCollinearIndex < points.length; firstNonCollinearIndex++) {
+            if (Point.orientation(points[0], points[firstNonEqualIndex], points[firstNonCollinearIndex]) != 0) {
                 break;
             }
         }
-        hull.push(points[indexPoint2 - 1]);
 
-        // Now we simply add the point to the stack based on the orientation.
-        for (int i = indexPoint2; i < points.length; i++) {
+        hull.push(points[firstNonCollinearIndex - 1]);
+
+        // Process the remaining points and update the hull
+        for (int i = firstNonCollinearIndex; i < points.length; i++) {
             Point top = hull.pop();
             while (Point.orientation(hull.peek(), top, points[i]) <= 0) {
                 top = hull.pop();
@@ -61,14 +61,10 @@ public GrahamScan(Point[] points) {
     }
 
     /**
-     * @return A stack of points representing the convex hull.
+     * @return An iterable collection of points representing the convex hull.
      */
     public Iterable<Point> hull() {
-        Stack<Point> s = new Stack<>();
-        for (Point p : hull) {
-            s.push(p);
-        }
-        return s;
+        return new ArrayList<>(hull);
     }
 
     public record Point(int x, int y) implements Comparable<Point> {
@@ -98,47 +94,41 @@ public int y() {
         }
 
         /**
-         * Finds the orientation of ordered triplet.
+         * Determines the orientation of the triplet (a, b, c).
          *
-         * @param a Co-ordinates of point a <int, int>
-         * @param b Co-ordinates of point a <int, int>
-         * @param c Co-ordinates of point a <int, int>
-         * @return { -1, 0, +1 } if a -→ b -→ c is a { clockwise, collinear; counterclockwise }
-         *     turn.
+         * @param a The first point
+         * @param b The second point
+         * @param c The third point
+         * @return -1 if (a, b, c) is clockwise, 0 if collinear, +1 if counterclockwise
          */
         public static int orientation(Point a, Point b, Point c) {
             int val = (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
-            if (val == 0) {
-                return 0;
-            }
-            return (val > 0) ? +1 : -1;
+            return Integer.compare(val, 0);
         }
 
         /**
-         * @param p2 Co-ordinate of point to compare to.
-         * This function will compare the points and will return a positive integer if the
-         * point is greater than the argument point and a negative integer if the point is
-         * less than the argument point.
+         * Compares this point with another point.
+         *
+         * @param p2 The point to compare to
+         * @return A positive integer if this point is greater, a negative integer if less, or 0 if equal
          */
+        @Override
         public int compareTo(Point p2) {
-            int res = Integer.compare(this.y, p2.y);
-            if (res == 0) {
-                res = Integer.compare(this.x, p2.x);
-            }
-            return res;
+            int cmpY = Integer.compare(this.y, p2.y);
+            return cmpY != 0 ? cmpY : Integer.compare(this.x, p2.x);
         }
 
         /**
-         * A helper function that will let us sort points by their polar order
-         * This function will compare the angle between 2 polar Co-ordinates
+         * Returns a comparator to sort points by their polar order relative to this point.
          *
-         * @return the comparator
+         * @return A polar order comparator
          */
         public Comparator<Point> polarOrder() {
             return new PolarOrder();
         }
 
         private final class PolarOrder implements Comparator<Point> {
+            @Override
             public int compare(Point p1, Point p2) {
                 int dx1 = p1.x - x;
                 int dy1 = p1.y - y;
@@ -146,32 +136,23 @@ public int compare(Point p1, Point p2) {
                 int dy2 = p2.y - y;
 
                 if (dy1 >= 0 && dy2 < 0) {
-                    return -1; // q1 above; q2 below
+                    return -1; // p1 above p2
                 } else if (dy2 >= 0 && dy1 < 0) {
-                    return +1; // q1 below; q2 above
-                } else if (dy1 == 0 && dy2 == 0) { // 3-collinear and horizontal
-                    if (dx1 >= 0 && dx2 < 0) {
-                        return -1;
-                    } else if (dx2 >= 0 && dx1 < 0) {
-                        return +1;
-                    } else {
-                        return 0;
-                    }
+                    return 1; // p1 below p2
+                } else if (dy1 == 0 && dy2 == 0) { // Collinear and horizontal
+                    return Integer.compare(dx2, dx1);
                 } else {
-                    return -orientation(Point.this, p1, p2); // both above or below
+                    return -orientation(Point.this, p1, p2); // Compare orientation
                 }
             }
         }
 
         /**
-         * Override of the toString method, necessary to compute the difference
-         * between the expected result and the derived result
-         *
-         * @return a string representation of any given 2D point in the format (x, y)
+         * @return A string representation of this point in the format (x, y)
          */
         @Override
         public String toString() {
-            return "(" + x + ", " + y + ")";
+            return String.format("(%d, %d)", x, y);
         }
     }
 }

From 7a5fe92b2ac96d9a2e6e571285f3a188d7ea01ea Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 10 Aug 2024 09:25:46 +0200
Subject: [PATCH 0263/1338] feat: `FlashSort` implementation (#5305)

---
 DIRECTORY.md                                  |   2 +
 .../com/thealgorithms/sorts/FlashSort.java    | 206 ++++++++++++++++++
 .../thealgorithms/sorts/FlashSortTest.java    |  90 ++++++++
 3 files changed, 298 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/FlashSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/FlashSortTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 22453235bfed..656597c3b20a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -501,6 +501,7 @@
             * [DualPivotQuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java)
             * [DutchNationalFlagSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java)
             * [ExchangeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/ExchangeSort.java)
+            * [FlashSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/FlashSort.java)
             * [GnomeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/GnomeSort.java)
             * [HeapSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/HeapSort.java)
             * [InsertionSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/InsertionSort.java)
@@ -874,6 +875,7 @@
             * [DualPivotQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java)
             * [DutchNationalFlagSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java)
             * [ExchangeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/ExchangeSortTest.java)
+            * [FlashSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/FlashSortTest.java)
             * [GnomeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/GnomeSortTest.java)
             * [HeapSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/HeapSortTest.java)
             * [InsertionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java)
diff --git a/src/main/java/com/thealgorithms/sorts/FlashSort.java b/src/main/java/com/thealgorithms/sorts/FlashSort.java
new file mode 100644
index 000000000000..e8dbf8c42742
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/FlashSort.java
@@ -0,0 +1,206 @@
+package com.thealgorithms.sorts;
+
+/**
+ * Implementation of Flash Sort algorithm that implements the SortAlgorithm interface.
+ *
+ * Sorts an array using the Flash Sort algorithm.
+ * <p>
+ * Flash Sort is a distribution sorting algorithm that partitions the data into
+ * different classes based on a classification array. It performs the sorting by
+ * first distributing the data elements into different buckets (or classes) and
+ * then permuting these buckets into the sorted order.
+ * <p>
+ * The method works as follows:
+ * <ol>
+ *     <li>Finds the minimum and maximum values in the array.</li>
+ *     <li>Initializes a classification array `L` to keep track of the number of elements in each class.</li>
+ *     <li>Computes a normalization constant `c1` to map elements into classes.</li>
+ *     <li>Classifies each element of the array into the corresponding bucket in the classification array.</li>
+ *     <li>Transforms the classification array to compute the starting indices of each bucket.</li>
+ *     <li>Permutes the elements of the array into sorted order based on the classification.</li>
+ *     <li>Uses insertion sort for the final arrangement to ensure complete sorting.</li>
+ * </ol>
+ */
+public class FlashSort implements SortAlgorithm {
+    private double classificationRatio = 0.45;
+
+    public FlashSort() {
+    }
+
+    public FlashSort(double classificationRatio) {
+        if (classificationRatio <= 0 || classificationRatio >= 1) {
+            throw new IllegalArgumentException("Classification ratio must be between 0 and 1 (exclusive).");
+        }
+        this.classificationRatio = classificationRatio;
+    }
+
+    public double getClassificationRatio() {
+        return classificationRatio;
+    }
+
+    public void setClassificationRatio(double classificationRatio) {
+        if (classificationRatio <= 0 || classificationRatio >= 1) {
+            throw new IllegalArgumentException("Classification ratio must be between 0 and 1 (exclusive).");
+        }
+        this.classificationRatio = classificationRatio;
+    }
+
+    /**
+     * Sorts an array using the Flash Sort algorithm.
+     *
+     * @param array the array to be sorted.
+     * @param <T> the type of elements to be sorted, must be comparable.
+     * @return the sorted array.
+     */
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        flashSort(array);
+        return array;
+    }
+
+    /**
+     * Sorts an array using the Flash Sort algorithm.
+     *
+     * @param arr the array to be sorted.
+     * @param <T> the type of elements to be sorted, must be comparable.
+     */
+    private <T extends Comparable<? super T>> void flashSort(T[] arr) {
+        if (arr.length == 0) {
+            return;
+        }
+
+        final T min = findMin(arr);
+        final int maxIndex = findMaxIndex(arr);
+
+        if (arr[maxIndex].compareTo(min) == 0) {
+            return; // All elements are the same
+        }
+
+        final int m = (int) (classificationRatio * arr.length);
+
+        final int[] classificationArray = new int[m];
+
+        final double c1 = (double) (m - 1) / arr[maxIndex].compareTo(min);
+
+        classify(arr, classificationArray, c1, min);
+
+        transform(classificationArray);
+
+        permute(arr, classificationArray, c1, min, arr.length, m);
+
+        insertionSort(arr);
+    }
+
+    /**
+     * Finds the minimum value in the array.
+     *
+     * @param arr the array to find the minimum value in.
+     * @param <T> the type of elements in the array, must be comparable.
+     * @return the minimum value in the array.
+     */
+    private <T extends Comparable<? super T>> T findMin(final T[] arr) {
+        T min = arr[0];
+        for (int i = 1; i < arr.length; i++) {
+            if (arr[i].compareTo(min) < 0) {
+                min = arr[i];
+            }
+        }
+        return min;
+    }
+
+    /**
+     * Finds the index of the maximum value in the array.
+     *
+     * @param arr the array to find the maximum value index in.
+     * @param <T> the type of elements in the array, must be comparable.
+     * @return the index of the maximum value in the array.
+     */
+    private <T extends Comparable<? super T>> int findMaxIndex(final T[] arr) {
+        int maxIndex = 0;
+        for (int i = 1; i < arr.length; i++) {
+            if (arr[i].compareTo(arr[maxIndex]) > 0) {
+                maxIndex = i;
+            }
+        }
+        return maxIndex;
+    }
+
+    /**
+     * Classifies elements of the array into the classification array classificationArray.
+     *
+     * @param arr the array to be classified.
+     * @param classificationArray the classification array holding the count of elements in each class.
+     * @param c1 the normalization constant used to map the elements to the classification array.
+     * @param min the minimum value in the array.
+     * @param <T> the type of elements in the array, must be comparable.
+     */
+    private <T extends Comparable<? super T>> void classify(final T[] arr, final int[] classificationArray, final double c1, final T min) {
+        for (int i = 0; i < arr.length; i++) {
+            int k = (int) (c1 * arr[i].compareTo(min));
+            classificationArray[k]++;
+        }
+    }
+
+    /**
+     * Transforms the classification array classificationArray into the starting index array.
+     *
+     * @param classificationArray the classification array holding the count of elements in each class.
+     */
+    private void transform(final int[] classificationArray) {
+        for (int i = 1; i < classificationArray.length; i++) {
+            classificationArray[i] += classificationArray[i - 1];
+        }
+    }
+
+    /**
+     * Permutes the array into sorted order based on the classification array classificationArray.
+     *
+     * @param arr the array to be permuted.
+     * @param classificationArray the classification array holding the count of elements in each class.
+     * @param c1 the normalization constant used to map the elements to the classification array.
+     * @param min the minimum value in the array.
+     * @param n the length of the array.
+     * @param m the number of classes in the classification array.
+     * @param <T> the type of elements in the array, must be comparable.
+     */
+    private <T extends Comparable<? super T>> void permute(final T[] arr, final int[] classificationArray, final double c1, T min, int n, int m) {
+        int move = 0;
+        int j = 0;
+        int k = m - 1;
+        T flash;
+        while (move < n - 1) {
+            while (j > classificationArray[k] - 1) {
+                j++;
+                k = (int) (c1 * arr[j].compareTo(min));
+            }
+            flash = arr[j];
+            while (j != classificationArray[k]) {
+                k = (int) (c1 * flash.compareTo(min));
+                T temp = arr[classificationArray[k] - 1];
+                arr[classificationArray[k] - 1] = flash;
+                flash = temp;
+                classificationArray[k]--;
+                move++;
+            }
+        }
+    }
+
+    /**
+     * Sorts an array using the insertion sort algorithm.
+     *
+     * @param arr the array to be sorted.
+     * @param <T> the type of elements to be sorted, must be comparable.
+     */
+    private <T extends Comparable<? super T>> void insertionSort(final T[] arr) {
+        int n = arr.length;
+        for (int i = 1; i < n; i++) {
+            T key = arr[i];
+            int j = i - 1;
+            while (j >= 0 && arr[j].compareTo(key) > 0) {
+                arr[j + 1] = arr[j];
+                j--;
+            }
+            arr[j + 1] = key;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/FlashSortTest.java b/src/test/java/com/thealgorithms/sorts/FlashSortTest.java
new file mode 100644
index 000000000000..6b1a74403a59
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/FlashSortTest.java
@@ -0,0 +1,90 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import org.junit.jupiter.api.DynamicTest;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestFactory;
+import org.junit.jupiter.api.function.Executable;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+public class FlashSortTest extends SortingAlgorithmTest {
+    private final FlashSort flashSort = new FlashSort();
+
+    public FlashSort getFlashSort() {
+        return flashSort;
+    }
+
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return getFlashSort();
+    }
+
+    @Test
+    public void testDefaultConstructor() {
+        double defaultRation = 0.45;
+        FlashSort sorter = new FlashSort();
+        assertEquals(defaultRation, sorter.getClassificationRatio());
+    }
+
+    @ParameterizedTest
+    @ValueSource(doubles = {0.1, 0.2, 0.5, 0.9})
+    public void testCustomConstructorValidRatio(double ratio) {
+        FlashSort sorter = new FlashSort(ratio);
+        assertEquals(ratio, sorter.getClassificationRatio());
+    }
+
+    @ParameterizedTest
+    @ValueSource(doubles = {0, 1, -0.1, 1.1})
+    public void testCustomConstructorInvalidRatio(double ratio) {
+        assertThrows(IllegalArgumentException.class, () -> new FlashSort(ratio));
+    }
+
+    @TestFactory
+    public Collection<DynamicTest> dynamicTestsForSorting() {
+        List<DynamicTest> dynamicTests = new ArrayList<>();
+        double[] ratios = {0.1, 0.2, 0.5, 0.9};
+
+        for (double ratio : ratios) {
+            FlashSort sorter = (FlashSort) getSortAlgorithm();
+            sorter.setClassificationRatio(ratio);
+            dynamicTests.addAll(createDynamicTestsForRatio(ratio));
+        }
+
+        return dynamicTests;
+    }
+
+    private Collection<DynamicTest> createDynamicTestsForRatio(double ratio) {
+        List<DynamicTest> dynamicTests = new ArrayList<>();
+        for (TestMethod testMethod : getTestMethodsFromSuperClass()) {
+            dynamicTests.add(DynamicTest.dynamicTest("Ratio: " + ratio + " - Test: " + testMethod.name(), testMethod.executable()));
+        }
+        return dynamicTests;
+    }
+
+    private List<TestMethod> getTestMethodsFromSuperClass() {
+        List<TestMethod> testMethods = new ArrayList<>();
+        Method[] methods = SortingAlgorithmTest.class.getDeclaredMethods();
+        for (Method method : methods) {
+            if (method.isAnnotationPresent(Test.class)) {
+                testMethods.add(new TestMethod(() -> {
+                    try {
+                        method.invoke(this);
+                    } catch (Exception e) {
+                        throw new RuntimeException(e);
+                    }
+                }, method.getName()));
+            }
+        }
+        return testMethods;
+    }
+
+    record TestMethod(Executable executable, String name) {
+    }
+}

From 197718842f382ff83deb5d8f24fe541e0afd1025 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 10 Aug 2024 13:21:44 +0200
Subject: [PATCH 0264/1338] refactor: cleanup `BucketSort`  (#5314)

---
 .../com/thealgorithms/sorts/BucketSort.java   | 163 ++++++++++--------
 .../thealgorithms/sorts/BucketSortTest.java   |  48 +-----
 2 files changed, 91 insertions(+), 120 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/BucketSort.java b/src/main/java/com/thealgorithms/sorts/BucketSort.java
index 2a48cca0f433..a6901ac339ac 100644
--- a/src/main/java/com/thealgorithms/sorts/BucketSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BucketSort.java
@@ -3,117 +3,128 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.Random;
 
 /**
- * Wikipedia: https://en.wikipedia.org/wiki/Bucket_sort
+ * BucketSort class provides a method to sort an array of elements using the Bucket Sort algorithm
+ * and implements the SortAlgorithm interface.
  */
-public final class BucketSort {
-    private BucketSort() {
-    }
+public class BucketSort implements SortAlgorithm {
 
-    public static void main(String[] args) {
-        int[] arr = new int[10];
+    // Constant that defines the divisor for determining the number of buckets
+    private static final int BUCKET_DIVISOR = 10;
 
-        /* generate 10 random numbers from -50 to 49 */
-        Random random = new Random();
-        for (int i = 0; i < arr.length; ++i) {
-            arr[i] = random.nextInt(100) - 50;
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array.length == 0) {
+            return array;
         }
 
-        bucketSort(arr);
+        T min = findMin(array);
+        T max = findMax(array);
+        int numberOfBuckets = calculateNumberOfBuckets(array.length);
 
-        /* check array is sorted or not */
-        for (int i = 0, limit = arr.length - 1; i < limit; ++i) {
-            assert arr[i] <= arr[i + 1];
-        }
+        List<List<T>> buckets = initializeBuckets(numberOfBuckets);
+        distributeElementsIntoBuckets(array, buckets, min, max, numberOfBuckets);
+
+        return concatenateBuckets(buckets, array);
     }
 
     /**
-     * BucketSort algorithms implements
+     * Calculates the number of buckets to use based on the size of the array.
      *
-     * @param arr the array contains elements
+     * @param arrayLength the length of the array
+     * @return the number of buckets
      */
-    public static int[] bucketSort(int[] arr) {
-        /* get max value of arr */
-        int max = max(arr);
-
-        /* get min value of arr */
-        int min = min(arr);
-
-        /* number of buckets */
-        int numberOfBuckets = max - min + 1;
-
-        List<List<Integer>> buckets = new ArrayList<>(numberOfBuckets);
+    private int calculateNumberOfBuckets(final int arrayLength) {
+        return Math.max(arrayLength / BUCKET_DIVISOR, 1);
+    }
 
-        /* init buckets */
-        for (int i = 0; i < numberOfBuckets; ++i) {
+    /**
+     * Initializes a list of empty buckets.
+     *
+     * @param numberOfBuckets the number of buckets to initialize
+     * @param <T> the type of elements to be sorted
+     * @return a list of empty buckets
+     */
+    private <T extends Comparable<T>> List<List<T>> initializeBuckets(int numberOfBuckets) {
+        List<List<T>> buckets = new ArrayList<>(numberOfBuckets);
+        for (int i = 0; i < numberOfBuckets; i++) {
             buckets.add(new ArrayList<>());
         }
-
-        /* store elements to buckets */
-        for (int value : arr) {
-            int hash = hash(value, min, numberOfBuckets);
-            buckets.get(hash).add(value);
-        }
-
-        /* sort individual bucket */
-        for (List<Integer> bucket : buckets) {
-            Collections.sort(bucket);
-        }
-
-        /* concatenate buckets to origin array */
-        int index = 0;
-        for (List<Integer> bucket : buckets) {
-            for (int value : bucket) {
-                arr[index++] = value;
-            }
-        }
-
-        return arr;
+        return buckets;
     }
 
     /**
-     * Get index of bucket which of our elements gets placed into it.
+     * Distributes elements from the array into the appropriate buckets.
      *
-     * @param elem the element of array to be sorted
-     * @param min min value of array
-     * @param numberOfBucket the number of bucket
-     * @return index of bucket
+     * @param array the array of elements to distribute
+     * @param buckets the list of buckets
+     * @param min the minimum value in the array
+     * @param max the maximum value in the array
+     * @param numberOfBuckets the total number of buckets
+     * @param <T> the type of elements in the array
      */
-    private static int hash(int elem, int min, int numberOfBucket) {
-        return (elem - min) / numberOfBucket;
+    private <T extends Comparable<T>> void distributeElementsIntoBuckets(T[] array, List<List<T>> buckets, final T min, final T max, final int numberOfBuckets) {
+        for (final T element : array) {
+            int bucketIndex = hash(element, min, max, numberOfBuckets);
+            buckets.get(bucketIndex).add(element);
+        }
     }
 
     /**
-     * Calculate max value of array
+     * Concatenates the sorted buckets back into the original array.
      *
-     * @param arr the array contains elements
-     * @return max value of given array
+     * @param buckets the list of sorted buckets
+     * @param array the original array
+     * @param <T> the type of elements in the array
+     * @return the sorted array
      */
-    public static int max(int[] arr) {
-        int max = arr[0];
-        for (int value : arr) {
-            if (value > max) {
-                max = value;
+    private <T extends Comparable<T>> T[] concatenateBuckets(List<List<T>> buckets, T[] array) {
+        int index = 0;
+        for (List<T> bucket : buckets) {
+            Collections.sort(bucket);
+            for (T element : bucket) {
+                array[index++] = element;
             }
         }
-        return max;
+        return array;
     }
 
     /**
-     * Calculate min value of array
+     * The method computes the index of the bucket in which a given element should be placed.
+     * This is done by "normalizing" the element within the range of the array's minimum (min) and maximum (max) values,
+     * and then mapping this normalized value to a specific bucket index.
      *
-     * @param arr the array contains elements
-     * @return min value of given array
+     * @param element the element of the array
+     * @param min the minimum value in the array
+     * @param max the maximum value in the array
+     * @param numberOfBuckets the total number of buckets
+     * @param <T> the type of elements in the array
+     * @return the index of the bucket
      */
-    public static int min(int[] arr) {
-        int min = arr[0];
-        for (int value : arr) {
-            if (value < min) {
-                min = value;
+    private <T extends Comparable<T>> int hash(final T element, final T min, final T max, final int numberOfBuckets) {
+        double range = max.compareTo(min);
+        double normalizedValue = element.compareTo(min) / range;
+        return (int) (normalizedValue * (numberOfBuckets - 1));
+    }
+
+    private <T extends Comparable<T>> T findMin(T[] array) {
+        T min = array[0];
+        for (T element : array) {
+            if (element.compareTo(min) < 0) {
+                min = element;
             }
         }
         return min;
     }
+
+    private <T extends Comparable<T>> T findMax(T[] array) {
+        T max = array[0];
+        for (T element : array) {
+            if (element.compareTo(max) > 0) {
+                max = element;
+            }
+        }
+        return max;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/BucketSortTest.java b/src/test/java/com/thealgorithms/sorts/BucketSortTest.java
index bd9d2e3d60cf..a2dcb8cadfd9 100644
--- a/src/test/java/com/thealgorithms/sorts/BucketSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/BucketSortTest.java
@@ -1,48 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-
-import org.junit.jupiter.api.Test;
-
-public class BucketSortTest {
-
-    @Test
-    public void bucketSortSingleIntegerArray() {
-        int[] inputArray = {4};
-        int[] outputArray = BucketSort.bucketSort(inputArray);
-        int[] expectedOutput = {4};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void bucketSortNonDuplicateIntegerArray() {
-        int[] inputArray = {6, 1, 99, 27, 15, 23, 36};
-        int[] outputArray = BucketSort.bucketSort(inputArray);
-        int[] expectedOutput = {1, 6, 15, 23, 27, 36, 99};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void bucketSortDuplicateIntegerArray() {
-        int[] inputArray = {6, 1, 27, 15, 23, 27, 36, 23};
-        int[] outputArray = BucketSort.bucketSort(inputArray);
-        int[] expectedOutput = {1, 6, 15, 23, 23, 27, 27, 36};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void bucketSortNonDuplicateIntegerArrayWithNegativeNum() {
-        int[] inputArray = {6, -1, 99, 27, -15, 23, -36};
-        int[] outputArray = BucketSort.bucketSort(inputArray);
-        int[] expectedOutput = {-36, -15, -1, 6, 23, 27, 99};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void bucketSortDuplicateIntegerArrayWithNegativeNum() {
-        int[] inputArray = {6, -1, 27, -15, 23, 27, -36, 23};
-        int[] outputArray = BucketSort.bucketSort(inputArray);
-        int[] expectedOutput = {-36, -15, -1, 6, 23, 23, 27, 27};
-        assertArrayEquals(outputArray, expectedOutput);
+public class BucketSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new BucketSort();
     }
 }

From 554b6cf0062b83dab5375adc49178eec1f266276 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 11 Aug 2024 19:44:22 +0200
Subject: [PATCH 0265/1338] refactor: simple improvements and cleanup for
 different sorts (#5318)

---
 .../sorts/DutchNationalFlagSort.java          | 22 ++++----
 .../com/thealgorithms/sorts/GnomeSort.java    | 53 ++-----------------
 .../com/thealgorithms/sorts/HeapSort.java     |  4 +-
 .../com/thealgorithms/sorts/QuickSort.java    | 12 ++---
 .../sorts/SelectionSortRecursive.java         |  4 +-
 .../com/thealgorithms/sorts/StoogeSort.java   | 24 ++++-----
 .../com/thealgorithms/sorts/StrandSort.java   |  8 +--
 .../com/thealgorithms/sorts/SwapSort.java     |  7 ++-
 .../java/com/thealgorithms/sorts/TimSort.java | 12 ++---
 9 files changed, 51 insertions(+), 95 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java b/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java
index 20b8f0ba1abc..abfcb452b29a 100644
--- a/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java
@@ -12,31 +12,31 @@
 public class DutchNationalFlagSort implements SortAlgorithm {
 
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] unsorted) {
-        return dutchNationalFlagSort(unsorted, unsorted[(int) Math.ceil((unsorted.length) / 2.0) - 1]);
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        return dutchNationalFlagSort(array, array[(int) Math.ceil((array.length) / 2.0) - 1]);
     }
 
-    public <T extends Comparable<T>> T[] sort(T[] unsorted, T intendedMiddle) {
-        return dutchNationalFlagSort(unsorted, intendedMiddle);
+    public <T extends Comparable<T>> T[] sort(T[] array, T intendedMiddle) {
+        return dutchNationalFlagSort(array, intendedMiddle);
     }
 
-    private <T extends Comparable<T>> T[] dutchNationalFlagSort(T[] arr, T intendedMiddle) {
+    private <T extends Comparable<T>> T[] dutchNationalFlagSort(final T[] array, final T intendedMiddle) {
         int i = 0;
         int j = 0;
-        int k = arr.length - 1;
+        int k = array.length - 1;
 
         while (j <= k) {
-            if (0 > arr[j].compareTo(intendedMiddle)) {
-                SortUtils.swap(arr, i, j);
+            if (0 > array[j].compareTo(intendedMiddle)) {
+                SortUtils.swap(array, i, j);
                 j++;
                 i++;
-            } else if (0 < arr[j].compareTo(intendedMiddle)) {
-                SortUtils.swap(arr, j, k);
+            } else if (0 < array[j].compareTo(intendedMiddle)) {
+                SortUtils.swap(array, j, k);
                 k--;
             } else {
                 j++;
             }
         }
-        return arr;
+        return array;
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/GnomeSort.java b/src/main/java/com/thealgorithms/sorts/GnomeSort.java
index 9bef6a2837b5..b074c271404d 100644
--- a/src/main/java/com/thealgorithms/sorts/GnomeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/GnomeSort.java
@@ -9,63 +9,20 @@
 public class GnomeSort implements SortAlgorithm {
 
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] arr) {
+    public <T extends Comparable<T>> T[] sort(final T[] array) {
         int i = 1;
         int j = 2;
-        while (i < arr.length) {
-            if (SortUtils.less(arr[i - 1], arr[i])) {
+        while (i < array.length) {
+            if (SortUtils.less(array[i - 1], array[i])) {
                 i = j++;
             } else {
-                SortUtils.swap(arr, i - 1, i);
+                SortUtils.swap(array, i - 1, i);
                 if (--i == 0) {
                     i = j++;
                 }
             }
         }
 
-        return null;
-    }
-
-    public static void main(String[] args) {
-        Integer[] integers = {
-            4,
-            23,
-            6,
-            78,
-            1,
-            26,
-            11,
-            23,
-            0,
-            -6,
-            3,
-            54,
-            231,
-            9,
-            12,
-        };
-        String[] strings = {
-            "c",
-            "a",
-            "e",
-            "b",
-            "d",
-            "dd",
-            "da",
-            "zz",
-            "AA",
-            "aa",
-            "aB",
-            "Hb",
-            "Z",
-        };
-        GnomeSort gnomeSort = new GnomeSort();
-
-        gnomeSort.sort(integers);
-        gnomeSort.sort(strings);
-
-        System.out.println("After sort : ");
-        SortUtils.print(integers);
-        SortUtils.print(strings);
+        return array;
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/HeapSort.java b/src/main/java/com/thealgorithms/sorts/HeapSort.java
index 91d556b17b16..e798fb91b925 100644
--- a/src/main/java/com/thealgorithms/sorts/HeapSort.java
+++ b/src/main/java/com/thealgorithms/sorts/HeapSort.java
@@ -25,13 +25,13 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         return array;
     }
 
-    private static <T extends Comparable<T>> void heapify(T[] array, int n) {
+    private <T extends Comparable<T>> void heapify(final T[] array, final int n) {
         for (int k = n / 2; k >= 1; k--) {
             siftDown(array, k, n);
         }
     }
 
-    private static <T extends Comparable<T>> void siftDown(T[] array, int k, int n) {
+    private <T extends Comparable<T>> void siftDown(final T[] array, int k, final int n) {
         while (2 * k <= n) {
             int j = 2 * k;
             if (j < n && SortUtils.less(array[j - 1], array[j])) {
diff --git a/src/main/java/com/thealgorithms/sorts/QuickSort.java b/src/main/java/com/thealgorithms/sorts/QuickSort.java
index 3ebdd96ce938..3abb1aae2306 100644
--- a/src/main/java/com/thealgorithms/sorts/QuickSort.java
+++ b/src/main/java/com/thealgorithms/sorts/QuickSort.java
@@ -25,9 +25,9 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
      * @param right The last index of an array
      * @param array The array to be sorted
      */
-    private static <T extends Comparable<T>> void doSort(T[] array, int left, int right) {
+    private static <T extends Comparable<T>> void doSort(T[] array, final int left, final int right) {
         if (left < right) {
-            int pivot = randomPartition(array, left, right);
+            final int pivot = randomPartition(array, left, right);
             doSort(array, left, pivot - 1);
             doSort(array, pivot, right);
         }
@@ -41,8 +41,8 @@ private static <T extends Comparable<T>> void doSort(T[] array, int left, int ri
      * @param right The last index of an array
      * @return the partition index of the array
      */
-    private static <T extends Comparable<T>> int randomPartition(T[] array, int left, int right) {
-        int randomIndex = left + (int) (Math.random() * (right - left + 1));
+    private static <T extends Comparable<T>> int randomPartition(T[] array, final int left, final int right) {
+        final int randomIndex = left + (int) (Math.random() * (right - left + 1));
         SortUtils.swap(array, randomIndex, right);
         return partition(array, left, right);
     }
@@ -56,8 +56,8 @@ private static <T extends Comparable<T>> int randomPartition(T[] array, int left
      * array
      */
     private static <T extends Comparable<T>> int partition(T[] array, int left, int right) {
-        int mid = (left + right) >>> 1;
-        T pivot = array[mid];
+        final int mid = (left + right) >>> 1;
+        final T pivot = array[mid];
 
         while (left <= right) {
             while (SortUtils.less(array[left], pivot)) {
diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java b/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
index 32bd58a1361a..9d24542de592 100644
--- a/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
@@ -27,7 +27,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
      * @param index the current index to start sorting from
      * @param <T>   the type of elements in the array (must be Comparable)
      */
-    private static <T extends Comparable<T>> void recursiveSelectionSort(T[] array, int index) {
+    private static <T extends Comparable<T>> void recursiveSelectionSort(T[] array, final int index) {
         if (index == array.length - 1) {
             return;
         }
@@ -46,7 +46,7 @@ private static <T extends Comparable<T>> void recursiveSelectionSort(T[] array,
      * @param <T>   the type of elements in the array
      * @return the index of the minimum element
      */
-    private static <T extends Comparable<T>> int findMinIndex(T[] array, int start) {
+    private static <T extends Comparable<T>> int findMinIndex(T[] array, final int start) {
         // Base case: if start is the last index, return start
         if (start == array.length - 1) {
             return start;
diff --git a/src/main/java/com/thealgorithms/sorts/StoogeSort.java b/src/main/java/com/thealgorithms/sorts/StoogeSort.java
index 25830109638a..2a6e04ce29c7 100644
--- a/src/main/java/com/thealgorithms/sorts/StoogeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/StoogeSort.java
@@ -15,20 +15,20 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         return array;
     }
 
-    public <T extends Comparable<T>> T[] sort(T[] unsortedArray, int start, int end) {
-        if (SortUtils.less(unsortedArray[end - 1], unsortedArray[start])) {
-            T temp = unsortedArray[start];
-            unsortedArray[start] = unsortedArray[end - 1];
-            unsortedArray[end - 1] = temp;
+    public <T extends Comparable<T>> T[] sort(final T[] array, final int start, final int end) {
+        if (SortUtils.less(array[end - 1], array[start])) {
+            final T temp = array[start];
+            array[start] = array[end - 1];
+            array[end - 1] = temp;
         }
 
-        int len = end - start;
-        if (len > 2) {
-            int third = len / 3;
-            sort(unsortedArray, start, end - third);
-            sort(unsortedArray, start + third, end);
-            sort(unsortedArray, start, end - third);
+        final int length = end - start;
+        if (length > 2) {
+            int third = length / 3;
+            sort(array, start, end - third);
+            sort(array, start + third, end);
+            sort(array, start, end - third);
         }
-        return unsortedArray;
+        return array;
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/StrandSort.java b/src/main/java/com/thealgorithms/sorts/StrandSort.java
index 58cd35628506..45bbe88d6793 100644
--- a/src/main/java/com/thealgorithms/sorts/StrandSort.java
+++ b/src/main/java/com/thealgorithms/sorts/StrandSort.java
@@ -13,14 +13,14 @@ public final class StrandSort implements SortAlgorithm {
      * Sorts the given array using the Strand Sort algorithm.
      *
      * @param <T> The type of elements to be sorted, must be Comparable.
-     * @param unsorted The array to be sorted.
+     * @param array The array to be sorted.
      * @return The sorted array.
      */
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] unsorted) {
-        List<T> unsortedList = new ArrayList<>(Arrays.asList(unsorted));
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        List<T> unsortedList = new ArrayList<>(Arrays.asList(array));
         List<T> sortedList = strandSort(unsortedList);
-        return sortedList.toArray(unsorted);
+        return sortedList.toArray(array);
     }
 
     /**
diff --git a/src/main/java/com/thealgorithms/sorts/SwapSort.java b/src/main/java/com/thealgorithms/sorts/SwapSort.java
index fe3597c0e2b4..b5c1c3892546 100644
--- a/src/main/java/com/thealgorithms/sorts/SwapSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SwapSort.java
@@ -11,11 +11,10 @@ public class SwapSort implements SortAlgorithm {
 
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
-        int len = array.length;
         int index = 0;
 
-        while (index < len - 1) {
-            int amountSmallerElements = this.getSmallerElementCount(array, index);
+        while (index < array.length - 1) {
+            final int amountSmallerElements = this.getSmallerElementCount(array, index);
 
             if (amountSmallerElements > 0) {
                 SortUtils.swap(array, index, index + amountSmallerElements);
@@ -27,7 +26,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         return array;
     }
 
-    private <T extends Comparable<T>> int getSmallerElementCount(T[] array, int index) {
+    private <T extends Comparable<T>> int getSmallerElementCount(final T[] array, final int index) {
         int counter = 0;
         for (int i = index + 1; i < array.length; i++) {
             if (SortUtils.less(array[i], array[index])) {
diff --git a/src/main/java/com/thealgorithms/sorts/TimSort.java b/src/main/java/com/thealgorithms/sorts/TimSort.java
index 85e16636c6ae..2d5bca2ef6f3 100644
--- a/src/main/java/com/thealgorithms/sorts/TimSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TimSort.java
@@ -12,25 +12,25 @@ class TimSort implements SortAlgorithm {
     private Comparable[] aux;
 
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] a) {
-        int n = a.length;
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        final int n = array.length;
 
         InsertionSort insertionSort = new InsertionSort();
         for (int i = 0; i < n; i += SUB_ARRAY_SIZE) {
-            insertionSort.sort(a, i, Math.min(i + SUB_ARRAY_SIZE, n));
+            insertionSort.sort(array, i, Math.min(i + SUB_ARRAY_SIZE, n));
         }
 
         aux = new Comparable[n];
         for (int sz = SUB_ARRAY_SIZE; sz < n; sz = sz + sz) {
             for (int lo = 0; lo < n - sz; lo += sz + sz) {
-                merge(a, lo, lo + sz - 1, Math.min(lo + sz + sz - 1, n - 1));
+                merge(array, lo, lo + sz - 1, Math.min(lo + sz + sz - 1, n - 1));
             }
         }
 
-        return a;
+        return array;
     }
 
-    private <T extends Comparable<T>> void merge(T[] a, int lo, int mid, int hi) {
+    private <T extends Comparable<T>> void merge(T[] a, final int lo, final int mid, final int hi) {
         int i = lo;
         int j = mid + 1;
         System.arraycopy(a, lo, aux, lo, hi + 1 - lo);

From 66bfaff807eb184d3f89613c90a9b5b96a89767a Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 11 Aug 2024 19:55:11 +0200
Subject: [PATCH 0266/1338] refactor: cleanup `CocktailShakerSort` (#5317)

---
 .../sorts/CocktailShakerSort.java             | 94 ++++++++++++-------
 .../sorts/CocktailShakerSortTest.java         | 68 +-------------
 2 files changed, 63 insertions(+), 99 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java b/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java
index c88c7bd099f6..600ae8d3efc9 100644
--- a/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java
@@ -1,57 +1,81 @@
 package com.thealgorithms.sorts;
 
 /**
+ * CocktailShakerSort class implements the Cocktail Shaker Sort algorithm,
+ * which is a bidirectional bubble sort. It sorts the array by passing
+ * through it back and forth, progressively moving the largest elements
+ * to the end and the smallest elements to the beginning.
+ *
  * @author Mateus Bizzo (https://github.com/MattBizzo)
  * @author Podshivalov Nikita (https://github.com/nikitap492)
  */
 class CocktailShakerSort implements SortAlgorithm {
 
     /**
-     * This method implements the Generic Cocktail Shaker Sort
+     * Sorts the given array using the Cocktail Shaker Sort algorithm.
      *
-     * @param array The array to be sorted Sorts the array in increasing order
+     * @param <T> The type of elements in the array, which must be comparable
+     * @param array The array to be sorted
+     * @return The sorted array
      */
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] array) {
-        int length = array.length;
+    public <T extends Comparable<T>> T[] sort(final T[] array) {
+        if (array.length == 0) {
+            return array;
+        }
+
         int left = 0;
-        int right = length - 1;
-        int swappedLeft;
-        int swappedRight;
+        int right = array.length - 1;
+
         while (left < right) {
-            // front
-            swappedRight = 0;
-            for (int i = left; i < right; i++) {
-                if (SortUtils.less(array[i + 1], array[i])) {
-                    SortUtils.swap(array, i, i + 1);
-                    swappedRight = i;
-                }
-            }
-            // back
-            right = swappedRight;
-            swappedLeft = length - 1;
-            for (int j = right; j > left; j--) {
-                if (SortUtils.less(array[j], array[j - 1])) {
-                    SortUtils.swap(array, j - 1, j);
-                    swappedLeft = j;
-                }
-            }
-            left = swappedLeft;
+            right = performForwardPass(array, left, right);
+            left = performBackwardPass(array, left, right);
         }
+
         return array;
     }
 
-    // Driver Program
-    public static void main(String[] args) {
-        // Integer Input
-        Integer[] integers = {4, 23, 6, 78, 1, 54, 231, 9, 12};
-        CocktailShakerSort shakerSort = new CocktailShakerSort();
+    /**
+     * Performs a forward pass through the array, moving larger elements to the end.
+     *
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @param array The array being sorted
+     * @param left  The current left boundary of the sorting area
+     * @param right The current right boundary of the sorting area
+     * @return The index of the last swapped element during this pass
+     */
+    private <T extends Comparable<T>> int performForwardPass(final T[] array, final int left, final int right) {
+        int lastSwappedIndex = left;
+
+        for (int i = left; i < right; i++) {
+            if (SortUtils.less(array[i + 1], array[i])) {
+                SortUtils.swap(array, i, i + 1);
+                lastSwappedIndex = i;
+            }
+        }
+
+        return lastSwappedIndex;
+    }
+
+    /**
+     * Performs a backward pass through the array, moving smaller elements to the beginning.
+     *
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @param array The array being sorted
+     * @param left  The current left boundary of the sorting area
+     * @param right The current right boundary of the sorting area
+     * @return The index of the last swapped element during this pass
+     */
+    private <T extends Comparable<T>> int performBackwardPass(final T[] array, final int left, final int right) {
+        int lastSwappedIndex = right;
 
-        // Output => 1 4 6 9 12 23 54 78 231
-        SortUtils.print(shakerSort.sort(integers));
+        for (int i = right; i > left; i--) {
+            if (SortUtils.less(array[i], array[i - 1])) {
+                SortUtils.swap(array, i - 1, i);
+                lastSwappedIndex = i;
+            }
+        }
 
-        // String Input
-        String[] strings = {"c", "a", "e", "b", "d"};
-        SortUtils.print(shakerSort.sort(strings));
+        return lastSwappedIndex;
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java b/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java
index 56628b78de02..45c1220275df 100644
--- a/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java
@@ -1,68 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-
-import org.junit.jupiter.api.Test;
-
-/**
- * @author Tabbygray (https://github.com/Tabbygray)
- * @see CocktailShakerSort
- */
-public class CocktailShakerSortTest {
-
-    private CocktailShakerSort cocktailShakerSort = new CocktailShakerSort();
-
-    @Test
-    public void cocktailShakerSortEmptyArray() {
-        Integer[] inputArray = {};
-        Integer[] outputArray = cocktailShakerSort.sort(inputArray);
-        Integer[] expectedOutput = {};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void cocktailShakerSortSingleStringElementArray() {
-        String[] inputArray = {"Test"};
-        String[] outputArray = cocktailShakerSort.sort(inputArray);
-        String[] expectedOutput = {"Test"};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void cocktailShakerSortIntegerArray() {
-        Integer[] inputArray = {2, 92, 1, 33, -33, 27, 5, 100, 78, 99, -100};
-        Integer[] outputArray = cocktailShakerSort.sort(inputArray);
-        Integer[] expectedOutput = {-100, -33, 1, 2, 5, 27, 33, 78, 92, 99, 100};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void cocktailShakerSortStringArray() {
-        String[] inputArray = {
-            "g3x1",
-            "dN62",
-            "oMdr",
-            "KL2b",
-            "JddJ",
-            "mvE8",
-            "Ej7Q",
-            "n7n7",
-            "LGTg",
-            "2E1w",
-        };
-        String[] outputArray = cocktailShakerSort.sort(inputArray);
-        String[] expectedOutput = {
-            "2E1w",
-            "Ej7Q",
-            "JddJ",
-            "KL2b",
-            "LGTg",
-            "dN62",
-            "g3x1",
-            "mvE8",
-            "n7n7",
-            "oMdr",
-        };
-        assertArrayEquals(outputArray, expectedOutput);
+public class CocktailShakerSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new CocktailShakerSort();
     }
 }

From 2837585705523db0d08cb03c70fc89985855729f Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 11 Aug 2024 20:00:47 +0200
Subject: [PATCH 0267/1338] refactor: `IntrospectiveSort` (#5316)

---
 .../sorts/IntrospectiveSort.java              | 123 +++++++++++++-----
 .../sorts/IntrospectiveSortTest.java          |  63 +--------
 2 files changed, 93 insertions(+), 93 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java b/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java
index 32d942dc78db..12ef197b931b 100644
--- a/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java
+++ b/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java
@@ -9,76 +9,131 @@ public class IntrospectiveSort implements SortAlgorithm {
 
     private static final int INSERTION_SORT_THRESHOLD = 16;
 
+    /**
+     * Sorts the given array using Introspective Sort, which combines quicksort, heapsort, and insertion sort.
+     *
+     * @param array The array to be sorted
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @return The sorted array
+     */
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] a) {
-        int n = a.length;
-        introSort(a, 0, n - 1, 2 * (int) (Math.log(n) / Math.log(2)));
-        return a;
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array == null || array.length <= 1) {
+            return array;
+        }
+        final int depth = 2 * (int) (Math.log(array.length) / Math.log(2));
+        introspectiveSort(array, 0, array.length - 1, depth);
+        return array;
     }
 
-    private static <T extends Comparable<T>> void introSort(T[] a, int low, int high, int depth) {
+    /**
+     * Performs introspective sort on the specified subarray.
+     *
+     * @param array The array to be sorted
+     * @param low   The starting index of the subarray
+     * @param high  The ending index of the subarray
+     * @param depth The current depth of recursion
+     * @param <T>   The type of elements in the array, which must be comparable
+     */
+    private static <T extends Comparable<T>> void introspectiveSort(T[] array, final int low, int high, final int depth) {
         while (high - low > INSERTION_SORT_THRESHOLD) {
             if (depth == 0) {
-                heapSort(a, low, high);
+                heapSort(array, low, high);
                 return;
             }
-            int pivotIndex = partition(a, low, high);
-            introSort(a, pivotIndex + 1, high, depth - 1);
+            final int pivotIndex = partition(array, low, high);
+            introspectiveSort(array, pivotIndex + 1, high, depth - 1);
             high = pivotIndex - 1;
         }
-        insertionSort(a, low, high);
+        insertionSort(array, low, high);
     }
 
-    private static <T extends Comparable<T>> int partition(T[] a, int low, int high) {
-        int pivotIndex = low + (int) (Math.random() * (high - low + 1));
-        SortUtils.swap(a, pivotIndex, high);
-        T pivot = a[high];
+    /**
+     * Partitions the array around a pivot.
+     *
+     * @param array The array to be partitioned
+     * @param low   The starting index of the subarray
+     * @param high  The ending index of the subarray
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @return The index of the pivot
+     */
+    private static <T extends Comparable<T>> int partition(T[] array, final int low, final int high) {
+        final int pivotIndex = low + (int) (Math.random() * (high - low + 1));
+        SortUtils.swap(array, pivotIndex, high);
+        final T pivot = array[high];
         int i = low - 1;
-        for (int j = low; j <= high - 1; j++) {
-            if (a[j].compareTo(pivot) <= 0) {
+        for (int j = low; j < high; j++) {
+            if (array[j].compareTo(pivot) <= 0) {
                 i++;
-                SortUtils.swap(a, i, j);
+                SortUtils.swap(array, i, j);
             }
         }
-        SortUtils.swap(a, i + 1, high);
+        SortUtils.swap(array, i + 1, high);
         return i + 1;
     }
 
-    private static <T extends Comparable<T>> void insertionSort(T[] a, int low, int high) {
+    /**
+     * Sorts a subarray using insertion sort.
+     *
+     * @param array The array to be sorted
+     * @param low   The starting index of the subarray
+     * @param high  The ending index of the subarray
+     * @param <T>   The type of elements in the array, which must be comparable
+     */
+    private static <T extends Comparable<T>> void insertionSort(T[] array, final int low, final int high) {
         for (int i = low + 1; i <= high; i++) {
-            T key = a[i];
+            final T key = array[i];
             int j = i - 1;
-            while (j >= low && a[j].compareTo(key) > 0) {
-                a[j + 1] = a[j];
+            while (j >= low && array[j].compareTo(key) > 0) {
+                array[j + 1] = array[j];
                 j--;
             }
-            a[j + 1] = key;
+            array[j + 1] = key;
         }
     }
 
-    private static <T extends Comparable<T>> void heapSort(T[] a, int low, int high) {
-        for (int i = (high + low - 1) / 2; i >= low; i--) {
-            heapify(a, i, high - low + 1, low);
+    /**
+     * Sorts a subarray using heapsort.
+     *
+     * @param array The array to be sorted
+     * @param low   The starting index of the subarray
+     * @param high  The ending index of the subarray
+     * @param <T>   The type of elements in the array, which must be comparable
+     */
+    private static <T extends Comparable<T>> void heapSort(T[] array, final int low, final int high) {
+        final int n = high - low + 1;
+        for (int i = (n / 2) - 1; i >= 0; i--) {
+            heapify(array, i, n, low);
         }
         for (int i = high; i > low; i--) {
-            SortUtils.swap(a, low, i);
-            heapify(a, low, i - low, low);
+            SortUtils.swap(array, low, i);
+            heapify(array, 0, i - low, low);
         }
     }
 
-    private static <T extends Comparable<T>> void heapify(T[] a, int i, int n, int low) {
-        int left = 2 * i - low + 1;
-        int right = 2 * i - low + 2;
+    /**
+     * Maintains the heap property for a subarray.
+     *
+     * @param array The array to be heapified
+     * @param i     The index to be heapified
+     * @param n     The size of the heap
+     * @param low   The starting index of the subarray
+     * @param <T>   The type of elements in the array, which must be comparable
+     */
+    private static <T extends Comparable<T>> void heapify(T[] array, final int i, final int n, final int low) {
+        final int left = 2 * i + 1;
+        final int right = 2 * i + 2;
         int largest = i;
-        if (left < n && a[left].compareTo(a[largest]) > 0) {
+
+        if (left < n && array[low + left].compareTo(array[low + largest]) > 0) {
             largest = left;
         }
-        if (right < n && a[right].compareTo(a[largest]) > 0) {
+        if (right < n && array[low + right].compareTo(array[low + largest]) > 0) {
             largest = right;
         }
         if (largest != i) {
-            SortUtils.swap(a, i, largest);
-            heapify(a, largest, n, low);
+            SortUtils.swap(array, low + i, low + largest);
+            heapify(array, largest, n, low);
         }
     }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java b/src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java
index a5c6905f7514..7760ee3849e2 100644
--- a/src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java
@@ -1,63 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
-import org.junit.jupiter.api.Test;
-
-public class IntrospectiveSortTest {
-    @Test
-    // valid test case
-    public void strandSortNonDuplicateTest() {
-        Integer[] expectedArray = {1, 2, 3, 4, 5};
-        Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
-        assertArrayEquals(expectedArray, actualList);
-    }
-
-    @Test
-    // valid test case
-    public void strandSortDuplicateTest() {
-        Integer[] expectedArray = {2, 2, 2, 5, 7};
-        Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
-        assertArrayEquals(expectedArray, actualList);
-    }
-
-    @Test
-    // valid test case
-    public void strandSortEmptyTest() {
-        Integer[] expectedArray = {};
-        Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
-        assertArrayEquals(expectedArray, actualList);
-    }
-
-    @Test
-    // valid test case
-    public void strandSortNullTest() {
-        Integer[] expectedArray = null;
-        assertThrows(NullPointerException.class, () -> { new IntrospectiveSort().sort(expectedArray); });
-    }
-
-    @Test
-    // valid test case
-    public void strandSortNegativeTest() {
-        Integer[] expectedArray = {-1, -2, -3, -4, -5};
-        Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
-        assertArrayEquals(expectedArray, actualList);
-    }
-
-    @Test
-    // valid test case
-    public void strandSortNegativeAndPositiveTest() {
-        Integer[] expectedArray = {-1, -2, -3, 4, 5};
-        Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
-        assertArrayEquals(expectedArray, actualList);
-    }
-
-    @Test
-    // valid test case
-    public void allSameTest() {
-        Integer[] expectedArray = {1, 1, 1, 1, 1};
-        Integer[] actualList = new IntrospectiveSort().sort(expectedArray);
-        assertArrayEquals(expectedArray, actualList);
+public class IntrospectiveSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new IntrospectiveSort();
     }
 }

From 41f76e0e89478c9c806b8bcbfbd72867b267ba91 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 13 Aug 2024 18:26:48 +0200
Subject: [PATCH 0268/1338] refactor: simple improvements and cleanup for
 different sorts (#5320)

---
 .../com/thealgorithms/sorts/CircleSort.java   | 28 ++++----
 .../com/thealgorithms/sorts/OddEvenSort.java  | 38 +++++++----
 .../thealgorithms/sorts/SelectionSort.java    | 13 ++--
 .../com/thealgorithms/sorts/SimpleSort.java   | 40 +----------
 .../com/thealgorithms/sorts/StrandSort.java   |  4 +-
 .../thealgorithms/sorts/SimpleSortTest.java   | 66 ++-----------------
 6 files changed, 54 insertions(+), 135 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/CircleSort.java b/src/main/java/com/thealgorithms/sorts/CircleSort.java
index 25c308b16e3c..b9b41be16701 100644
--- a/src/main/java/com/thealgorithms/sorts/CircleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CircleSort.java
@@ -7,25 +7,29 @@ public class CircleSort implements SortAlgorithm {
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
-        int n = array.length;
-        if (n == 0) {
+        if (array.length == 0) {
             return array;
         }
-        while (doSort(array, 0, n - 1)) {
+        while (doSort(array, 0, array.length - 1)) {
         }
         return array;
     }
 
-    /* This method implements the cyclic sort recursive version
+    /**
+     * Recursively sorts the array in a circular manner by comparing elements
+     * from the start and end of the current segment.
+     *
+     * @param <T>   The type of elements in the array, which must be comparable
      * @param array The array to be sorted
-     * @param the left boundary of the part currently being sorted
-     * @param the right boundary of the part currently being sorted
+     * @param left  The left boundary of the current segment being sorted
+     * @param right The right boundary of the current segment being sorted
+     * @return true if any elements were swapped during the sort; false otherwise
      */
-    private <T extends Comparable<T>> Boolean doSort(T[] array, int left, int right) {
+    private <T extends Comparable<T>> boolean doSort(final T[] array, final int left, final int right) {
         boolean swapped = false;
 
         if (left == right) {
-            return Boolean.FALSE;
+            return false;
         }
 
         int low = left;
@@ -45,10 +49,10 @@ private <T extends Comparable<T>> Boolean doSort(T[] array, int left, int right)
             swapped = true;
         }
 
-        int mid = left + (right - left) / 2;
-        Boolean leftHalf = doSort(array, left, mid);
-        Boolean rightHalf = doSort(array, mid + 1, right);
+        final int mid = left + (right - left) / 2;
+        final boolean leftHalfSwapped = doSort(array, left, mid);
+        final boolean rightHalfSwapped = doSort(array, mid + 1, right);
 
-        return swapped || leftHalf || rightHalf;
+        return swapped || leftHalfSwapped || rightHalfSwapped;
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/OddEvenSort.java b/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
index 8db85f39e9ac..ac94982c1474 100644
--- a/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
+++ b/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
@@ -13,29 +13,39 @@ public final class OddEvenSort implements SortAlgorithm {
      * Sorts the given array using the Odd-Even Sort algorithm.
      *
      * @param <T> the type of elements in the array, which must implement the Comparable interface
-     * @param arr the array to be sorted
+     * @param array the array to be sorted
      * @return the sorted array
      */
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] arr) {
+    public <T extends Comparable<T>> T[] sort(T[] array) {
         boolean sorted = false;
         while (!sorted) {
-            sorted = true;
+            sorted = performOddSort(array);
+            sorted = performEvenSort(array) && sorted;
+        }
+
+        return array;
+    }
 
-            for (int i = 1; i < arr.length - 1; i += 2) {
-                if (arr[i].compareTo(arr[i + 1]) > 0) {
-                    SortUtils.swap(arr, i, i + 1);
-                    sorted = false;
-                }
+    private <T extends Comparable<T>> boolean performOddSort(T[] array) {
+        boolean sorted = true;
+        for (int i = 1; i < array.length - 1; i += 2) {
+            if (array[i].compareTo(array[i + 1]) > 0) {
+                SortUtils.swap(array, i, i + 1);
+                sorted = false;
             }
+        }
+        return sorted;
+    }
 
-            for (int i = 0; i < arr.length - 1; i += 2) {
-                if (arr[i].compareTo(arr[i + 1]) > 0) {
-                    SortUtils.swap(arr, i, i + 1);
-                    sorted = false;
-                }
+    private <T extends Comparable<T>> boolean performEvenSort(T[] array) {
+        boolean sorted = true;
+        for (int i = 0; i < array.length - 1; i += 2) {
+            if (array[i].compareTo(array[i + 1]) > 0) {
+                SortUtils.swap(array, i, i + 1);
+                sorted = false;
             }
         }
-        return arr;
+        return sorted;
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSort.java b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
index 8c815c6cb5fc..dbb2b88ffcef 100644
--- a/src/main/java/com/thealgorithms/sorts/SelectionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
@@ -10,18 +10,17 @@ public class SelectionSort implements SortAlgorithm {
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
-        // One by one move the boundary of the unsorted subarray
-        for (int i = 0; i < array.length - 1; i++) {
 
-            // Swap the remaining minimum element with the current element
-            SortUtils.swap(array, i, findIndexOfMin(array, i));
+        for (int i = 0; i < array.length - 1; i++) {
+            final int minIndex = findIndexOfMin(array, i);
+            SortUtils.swap(array, i, minIndex);
         }
         return array;
     }
 
-    private static <T extends Comparable<T>> int findIndexOfMin(T[] array, final int start) {
-        int minIndex = start;
-        for (int i = start + 1; i < array.length; i++) {
+    private static <T extends Comparable<T>> int findIndexOfMin(T[] array, final int startIndex) {
+        int minIndex = startIndex;
+        for (int i = startIndex + 1; i < array.length; i++) {
             if (array[i].compareTo(array[minIndex]) < 0) {
                 minIndex = i;
             }
diff --git a/src/main/java/com/thealgorithms/sorts/SimpleSort.java b/src/main/java/com/thealgorithms/sorts/SimpleSort.java
index 110bc6e4c5b7..a03223cb01a1 100644
--- a/src/main/java/com/thealgorithms/sorts/SimpleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SimpleSort.java
@@ -1,51 +1,15 @@
 package com.thealgorithms.sorts;
 
 public class SimpleSort implements SortAlgorithm {
-
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
-        final int length = array.length;
-
-        for (int i = 0; i < length; i++) {
-            for (int j = i + 1; j < length; j++) {
+        for (int i = 0; i < array.length; i++) {
+            for (int j = i + 1; j < array.length; j++) {
                 if (SortUtils.less(array[j], array[i])) {
                     SortUtils.swap(array, i, j);
                 }
             }
         }
-
         return array;
     }
-
-    public static void main(String[] args) {
-        // ==== Int =======
-        Integer[] a = {3, 7, 45, 1, 33, 5, 2, 9};
-        System.out.print("unsorted: ");
-        SortUtils.print(a);
-        System.out.println();
-
-        new SimpleSort().sort(a);
-        System.out.print("sorted: ");
-        SortUtils.print(a);
-        System.out.println();
-
-        // ==== String =======
-        String[] b = {
-            "banana",
-            "berry",
-            "orange",
-            "grape",
-            "peach",
-            "cherry",
-            "apple",
-            "pineapple",
-        };
-        System.out.print("unsorted: ");
-        SortUtils.print(b);
-        System.out.println();
-
-        new SimpleSort().sort(b);
-        System.out.print("sorted: ");
-        SortUtils.print(b);
-    }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/StrandSort.java b/src/main/java/com/thealgorithms/sorts/StrandSort.java
index 45bbe88d6793..147d11340d8a 100644
--- a/src/main/java/com/thealgorithms/sorts/StrandSort.java
+++ b/src/main/java/com/thealgorithms/sorts/StrandSort.java
@@ -38,9 +38,9 @@ private static <T extends Comparable<? super T>> List<T> strandSort(List<T> list
         List<T> result = new ArrayList<>();
         while (!list.isEmpty()) {
             final List<T> sorted = new ArrayList<>();
-            sorted.add(list.remove(0));
+            sorted.add(list.removeFirst());
             for (int i = 0; i < list.size();) {
-                if (sorted.get(sorted.size() - 1).compareTo(list.get(i)) <= 0) {
+                if (sorted.getLast().compareTo(list.get(i)) <= 0) {
                     sorted.add(list.remove(i));
                 } else {
                     i++;
diff --git a/src/test/java/com/thealgorithms/sorts/SimpleSortTest.java b/src/test/java/com/thealgorithms/sorts/SimpleSortTest.java
index e476b97b96e0..887b314e46ff 100644
--- a/src/test/java/com/thealgorithms/sorts/SimpleSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SimpleSortTest.java
@@ -1,66 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-
-import org.junit.jupiter.api.Test;
-
-public class SimpleSortTest {
-
-    private SimpleSort simpleSort = new SimpleSort();
-
-    @Test
-    public void simpleSortEmptyArray() {
-        Integer[] inputArray = {};
-        Integer[] outputArray = simpleSort.sort(inputArray);
-        Integer[] expectedOutput = {};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void simpleSortSingleIntegerArray() {
-        Integer[] inputArray = {4};
-        Integer[] outputArray = simpleSort.sort(inputArray);
-        Integer[] expectedOutput = {4};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void simpleSortSingleStringArray() {
-        String[] inputArray = {"s"};
-        String[] outputArray = simpleSort.sort(inputArray);
-        String[] expectedOutput = {"s"};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void simpleSortNonDuplicateIntegerArray() {
-        Integer[] inputArray = {6, -1, 99, 27, -15, 23, -36};
-        Integer[] outputArray = simpleSort.sort(inputArray);
-        Integer[] expectedOutput = {-36, -15, -1, 6, 23, 27, 99};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void simpleSortDuplicateIntegerArray() {
-        Integer[] inputArray = {6, -1, 27, -15, 23, 27, -36, 23};
-        Integer[] outputArray = simpleSort.sort(inputArray);
-        Integer[] expectedOutput = {-36, -15, -1, 6, 23, 23, 27, 27};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void simpleSortNonDuplicateStringArray() {
-        String[] inputArray = {"s", "b", "k", "a", "d", "c", "h"};
-        String[] outputArray = simpleSort.sort(inputArray);
-        String[] expectedOutput = {"a", "b", "c", "d", "h", "k", "s"};
-        assertArrayEquals(outputArray, expectedOutput);
-    }
-
-    @Test
-    public void simpleSortDuplicateStringArray() {
-        String[] inputArray = {"s", "b", "d", "a", "d", "c", "h", "b"};
-        String[] outputArray = simpleSort.sort(inputArray);
-        String[] expectedOutput = {"a", "b", "b", "c", "d", "d", "h", "s"};
-        assertArrayEquals(outputArray, expectedOutput);
+public class SimpleSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new SimpleSort();
     }
 }

From 8d0dd3ef32d78a767d81ac0f71ade70e524bb1d1 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 13 Aug 2024 18:30:35 +0200
Subject: [PATCH 0269/1338] refactor: cleanup `DualPivotQuickSort` (#5319)

---
 .../sorts/DualPivotQuickSort.java             | 108 ++++++++----------
 .../sorts/DualPivotQuickSortTest.java         |  62 +---------
 2 files changed, 53 insertions(+), 117 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java b/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java
index b02168f627c3..ada745acd25a 100644
--- a/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java
@@ -9,26 +9,33 @@
 public class DualPivotQuickSort implements SortAlgorithm {
 
     /**
-     * This method implements the Dual pivot Quick Sort
+     * Sorts an array using the Dual Pivot QuickSort algorithm.
      *
-     * @param array The array to be sorted Sorts the array in increasing order
+     * @param array The array to be sorted
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @return The sorted array
      */
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] array) {
+    public <T extends Comparable<T>> T[] sort(final T[] array) {
+        if (array.length <= 1) {
+            return array;
+        }
+
         dualPivotQuicksort(array, 0, array.length - 1);
         return array;
     }
 
     /**
-     * The sorting process
+     * Recursively applies the Dual Pivot QuickSort algorithm to subarrays.
      *
-     * @param left  The first index of an array
-     * @param right The last index of an array
      * @param array The array to be sorted
+     * @param left  The starting index of the subarray
+     * @param right The ending index of the subarray
+     * @param <T>   The type of elements in the array, which must be comparable
      */
-    private static <T extends Comparable<T>> void dualPivotQuicksort(T[] array, int left, int right) {
+    private static <T extends Comparable<T>> void dualPivotQuicksort(final T[] array, final int left, final int right) {
         if (left < right) {
-            int[] pivots = partition(array, left, right);
+            final int[] pivots = partition(array, left, right);
 
             dualPivotQuicksort(array, left, pivots[0] - 1);
             dualPivotQuicksort(array, pivots[0] + 1, pivots[1] - 1);
@@ -37,70 +44,53 @@ private static <T extends Comparable<T>> void dualPivotQuicksort(T[] array, int
     }
 
     /**
-     * This method finds the partition indices for an array
+     * Partitions the array into three parts using two pivots.
      *
-     * @param array The array to be sorted
-     * @param left  The first index of an array
-     * @param right The last index of an array Finds the partition index of an array
+     * @param array The array to be partitioned
+     * @param left  The starting index for partitioning
+     * @param right The ending index for partitioning
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @return An array containing the indices of the two pivots
      */
-    private static <T extends Comparable<T>> int[] partition(T[] array, int left, int right) {
-        if (array[left].compareTo(array[right]) > 0) {
+    private static <T extends Comparable<T>> int[] partition(final T[] array, int left, final int right) {
+        if (SortUtils.greater(array[left], array[right])) {
             SortUtils.swap(array, left, right);
         }
 
-        T pivot1 = array[left];
-        T pivot2 = array[right];
+        final T pivot1 = array[left];
+        final T pivot2 = array[right];
 
-        int j = left + 1;
-        int less = left + 1;
-        int great = right - 1;
+        int pivot1End = left + 1;
+        int low = left + 1;
+        int high = right - 1;
 
-        while (less <= great) {
-            // If element is less than pivot1
-            if (array[less].compareTo(pivot1) < 0) {
-                SortUtils.swap(array, less, left++);
-            }
-
-            // If element is greater or equal to pivot2
-            else if (array[less].compareTo(pivot2) >= 0) {
-                while (less < great && array[great].compareTo(pivot2) > 0) {
-                    great--;
+        while (low <= high) {
+            if (SortUtils.less(array[low], pivot1)) {
+                SortUtils.swap(array, low, pivot1End);
+                pivot1End++;
+            } else if (SortUtils.greaterOrEqual(array[low], pivot2)) {
+                while (low < high && SortUtils.greater(array[high], pivot2)) {
+                    high--;
                 }
+                SortUtils.swap(array, low, high);
+                high--;
 
-                SortUtils.swap(array, less, great--);
-
-                if (array[less].compareTo(pivot1) < 0) {
-                    SortUtils.swap(array, less, left++);
+                if (SortUtils.less(array[low], pivot1)) {
+                    SortUtils.swap(array, low, pivot1End);
+                    pivot1End++;
                 }
             }
-
-            less++;
+            low++;
         }
-        j--;
-        great++;
-        // Bring the pivots to their appropriate positions
-        SortUtils.swap(array, left, j);
-        SortUtils.swap(array, right, great);
 
-        // return the pivots' indices
-        return new int[] {less, great};
-    }
+        // Place the pivots in their correct positions
+        pivot1End--;
+        high++;
 
-    /**
-     * Main method
-     *
-     * @param args the command line arguments
-     */
-    public static void main(String[] args) {
-        Integer[] array = {24, 8, -42, 75, -29, -77, 38, 57};
-        DualPivotQuickSort dualPivotQuickSort = new DualPivotQuickSort();
-        dualPivotQuickSort.sort(array);
-        for (int i = 0; i < array.length; i++) {
-            System.out.print(array[i] + " ");
-        }
-    }
+        SortUtils.swap(array, left, pivot1End);
+        SortUtils.swap(array, right, high);
 
-    /*
-     * References: https://www.geeksforgeeks.org/dual-pivot-quicksort/
-     */
+        // Return the indices of the pivots
+        return new int[] {low, high};
+    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java b/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java
index 112f38277776..0b9cc1de5886 100644
--- a/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java
@@ -1,62 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-
-import org.junit.jupiter.api.Test;
-
-/**
- * @author Debasish Biswas (https://github.com/debasishbsws)
- * @see DualPivotQuickSort
- */
-class DualPivotQuickSortTest {
-
-    private DualPivotQuickSort dualPivotquickSort = new DualPivotQuickSort();
-
-    @Test
-    void quickSortEmptyArrayShouldPass() {
-        Integer[] array = {};
-        Integer[] sorted = dualPivotquickSort.sort(array);
-        Integer[] expected = {};
-        assertArrayEquals(expected, sorted);
-    }
-
-    @Test
-    void quickSortSingleValueArrayShouldPass() {
-        Integer[] array = {7};
-        Integer[] sorted = dualPivotquickSort.sort(array);
-        Integer[] expected = {7};
-        assertArrayEquals(expected, sorted);
-    }
-
-    @Test
-    void quickSortWithIntegerArrayShouldPass() {
-        Integer[] array = {49, 4, 36, 9, 144, 1};
-        Integer[] sorted = dualPivotquickSort.sort(array);
-        Integer[] expected = {1, 4, 9, 36, 49, 144};
-        assertArrayEquals(expected, sorted);
-    }
-
-    @Test
-    void quickSortForArrayWithNegativeValuesShouldPass() {
-        Integer[] array = {49, -36, -124, -49, 12, 9};
-        Integer[] sorted = dualPivotquickSort.sort(array);
-        Integer[] expected = {-124, -49, -36, 9, 12, 49};
-        assertArrayEquals(expected, sorted);
-    }
-
-    @Test
-    void quickSortForArrayWithDuplicateValuesShouldPass() {
-        Integer[] array = {36, 1, 49, 1, 4, 9};
-        Integer[] sorted = dualPivotquickSort.sort(array);
-        Integer[] expected = {1, 1, 4, 9, 36, 49};
-        assertArrayEquals(expected, sorted);
-    }
-
-    @Test
-    void quickSortWithStringArrayShouldPass() {
-        String[] array = {"cat", "ant", "eat", "boss", "dog", "apple"};
-        String[] sorted = dualPivotquickSort.sort(array);
-        String[] expected = {"ant", "apple", "boss", "cat", "dog", "eat"};
-        assertArrayEquals(expected, sorted);
+class DualPivotQuickSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new DualPivotQuickSort();
     }
 }

From 4fc646809c4a050e6403d6acbecfefc23e7898df Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 15 Aug 2024 00:20:47 +0200
Subject: [PATCH 0270/1338] Chore(deps-dev): bump
 org.junit.jupiter:junit-jupiter-api from 5.10.3 to 5.11.0 (#5326)

Chore(deps-dev): bump org.junit.jupiter:junit-jupiter-api

Bumps [org.junit.jupiter:junit-jupiter-api](https://github.com/junit-team/junit5) from 5.10.3 to 5.11.0.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.10.3...r5.11.0)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter-api
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 0c69e1f50732..b048e934271e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -44,7 +44,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>5.10.3</version>
+            <version>5.11.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From b8d0978e01402d30d395bb46a5bb07e89f86272b Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 15 Aug 2024 09:23:37 +0300
Subject: [PATCH 0271/1338] Chore(deps): bump org.junit:junit-bom from 5.10.3
 to 5.11.0 (#5327)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.10.3 to 5.11.0.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.10.3...r5.11.0)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b048e934271e..63efa60e3c44 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.10.3</version>
+                <version>5.11.0</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From c4e0adbdd55976096f3d2a5281c872c1d3c5c5d6 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 15 Aug 2024 09:30:46 +0300
Subject: [PATCH 0272/1338] Chore(deps-dev): bump
 org.junit.jupiter:junit-jupiter from 5.10.3 to 5.11.0 (#5328)

Chore(deps-dev): bump org.junit.jupiter:junit-jupiter

Bumps [org.junit.jupiter:junit-jupiter](https://github.com/junit-team/junit5) from 5.10.3 to 5.11.0.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.10.3...r5.11.0)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 63efa60e3c44..6387ced0c224 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.10.3</version>
+            <version>5.11.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 777de1da9994cb406bd37e8d7ba461a9f7e0dd3a Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 15 Aug 2024 10:25:23 +0200
Subject: [PATCH 0273/1338] refactor: cleanup `CycleSort` (#5321)

---
 .../com/thealgorithms/sorts/CycleSort.java    | 103 +++++++++---------
 1 file changed, 54 insertions(+), 49 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/CycleSort.java b/src/main/java/com/thealgorithms/sorts/CycleSort.java
index e254dd8102d2..4ef051419cbb 100644
--- a/src/main/java/com/thealgorithms/sorts/CycleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CycleSort.java
@@ -9,74 +9,79 @@ class CycleSort implements SortAlgorithm {
     /**
      * Sorts an array of comparable elements using the cycle sort algorithm.
      *
-     * @param array the array to be sorted
-     * @param <T> the type of elements in the array, must be comparable
-     * @return the sorted array
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @param array The array to be sorted
+     * @return The sorted array
      */
     @Override
-    public <T extends Comparable<T>> T[] sort(T[] array) {
-        for (int cycleStart = 0; cycleStart <= array.length - 2; cycleStart++) {
-            T item = array[cycleStart];
+    public <T extends Comparable<T>> T[] sort(final T[] array) {
+        final int length = array.length;
 
-            // Find the position where we put the element
-            int pos = cycleStart;
-            for (int i = cycleStart + 1; i < array.length; i++) {
-                if (SortUtils.less(array[i], item)) {
-                    pos++;
-                }
-            }
+        for (int cycleStart = 0; cycleStart <= length - 2; cycleStart++) {
+            T item = array[cycleStart];
+            int pos = findPosition(array, cycleStart, item);
 
-            // If the item is already in the correct position
             if (pos == cycleStart) {
-                continue;
-            }
-
-            // Ignore all duplicate elements
-            while (item.compareTo(array[pos]) == 0) {
-                pos++;
+                continue; // Item is already in the correct position
             }
 
-            // Put the item to its correct position
-            if (pos != cycleStart) {
-                item = replace(array, pos, item);
-            }
+            item = placeItem(array, item, pos);
 
             // Rotate the rest of the cycle
             while (pos != cycleStart) {
-                pos = cycleStart;
-
-                // Find the position where we put the element
-                for (int i = cycleStart + 1; i < array.length; i++) {
-                    if (SortUtils.less(array[i], item)) {
-                        pos++;
-                    }
-                }
-
-                // Ignore all duplicate elements
-                while (item.compareTo(array[pos]) == 0) {
-                    pos++;
-                }
-
-                // Put the item to its correct position
-                if (item != array[pos]) {
-                    item = replace(array, pos, item);
-                }
+                pos = findPosition(array, cycleStart, item);
+                item = placeItem(array, item, pos);
             }
         }
         return array;
     }
 
+    /**
+     * Finds the correct position for the given item starting from cycleStart.
+     *
+     * @param <T>        The type of elements in the array, which must be comparable
+     * @param array      The array to be sorted
+     * @param cycleStart The starting index of the cycle
+     * @param item       The item whose position is to be found
+     * @return The correct position of the item
+     */
+    private <T extends Comparable<T>> int findPosition(final T[] array, final int cycleStart, final T item) {
+        int pos = cycleStart;
+        for (int i = cycleStart + 1; i < array.length; i++) {
+            if (SortUtils.less(array[i], item)) {
+                pos++;
+            }
+        }
+        return pos;
+    }
+
+    /**
+     * Places the item in its correct position, handling duplicates, and returns the displaced item.
+     *
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @param array The array being sorted
+     * @param item  The item to be placed
+     * @param pos   The position where the item is to be placed
+     * @return The displaced item
+     */
+    private <T extends Comparable<T>> T placeItem(final T[] array, final T item, int pos) {
+        while (item.compareTo(array[pos]) == 0) {
+            pos++;
+        }
+        return replace(array, pos, item);
+    }
+
     /**
      * Replaces an element in the array with the given item and returns the replaced item.
      *
-     * @param array the array in which the replacement will occur
-     * @param pos the position at which the replacement will occur
-     * @param item the item to be placed in the array
-     * @param <T> the type of elements in the array, must be comparable
-     * @return the replaced item
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @param array The array in which the replacement will occur
+     * @param pos   The position at which the replacement will occur
+     * @param item  The item to be placed in the array
+     * @return The replaced item
      */
-    private <T extends Comparable<T>> T replace(T[] array, int pos, T item) {
-        T replacedItem = array[pos];
+    private <T extends Comparable<T>> T replace(final T[] array, final int pos, final T item) {
+        final T replacedItem = array[pos];
         array[pos] = item;
         return replacedItem;
     }

From 134b42c7ff3e838dcba0a85d386822d0dd8385fc Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 15 Aug 2024 10:30:53 +0200
Subject: [PATCH 0274/1338] refactor: `BloomFilter` (#5325)

---
 .../bloomfilter/BloomFilter.java              | 82 +++++++++++++++----
 .../bloomfilter/BloomFilterTest.java          | 44 +++++++++-
 2 files changed, 106 insertions(+), 20 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
index a327690d7896..33ea22c3d271 100644
--- a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
+++ b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
@@ -2,35 +2,61 @@
 
 import java.util.BitSet;
 
+/**
+ * A generic BloomFilter implementation for probabilistic membership checking.
+ *
+ * @param <T> The type of elements to be stored in the Bloom filter.
+ */
 public class BloomFilter<T> {
 
-    private int numberOfHashFunctions;
-    private BitSet bitArray;
-    private Hash<T>[] hashFunctions;
+    private final int numberOfHashFunctions;
+    private final BitSet bitArray;
+    private final Hash<T>[] hashFunctions;
 
-    public BloomFilter(int numberOfHashFunctions, int n) {
+    /**
+     * Constructs a BloomFilter with a specified number of hash functions and bit array size.
+     *
+     * @param numberOfHashFunctions the number of hash functions to use
+     * @param bitArraySize          the size of the bit array
+     */
+    @SuppressWarnings("unchecked")
+    public BloomFilter(int numberOfHashFunctions, int bitArraySize) {
         this.numberOfHashFunctions = numberOfHashFunctions;
-        hashFunctions = new Hash[numberOfHashFunctions];
-        bitArray = new BitSet(n);
-        insertHash();
+        this.bitArray = new BitSet(bitArraySize);
+        this.hashFunctions = new Hash[numberOfHashFunctions];
+        initializeHashFunctions();
     }
 
-    private void insertHash() {
+    /**
+     * Initializes the hash functions with unique indices.
+     */
+    private void initializeHashFunctions() {
         for (int i = 0; i < numberOfHashFunctions; i++) {
-            hashFunctions[i] = new Hash(i);
+            hashFunctions[i] = new Hash<>(i);
         }
     }
 
+    /**
+     * Inserts an element into the Bloom filter.
+     *
+     * @param key the element to insert
+     */
     public void insert(T key) {
         for (Hash<T> hash : hashFunctions) {
-            int position = hash.compute(key) % bitArray.size();
+            int position = Math.abs(hash.compute(key) % bitArray.size());
             bitArray.set(position);
         }
     }
 
+    /**
+     * Checks if an element might be in the Bloom filter.
+     *
+     * @param key the element to check
+     * @return {@code true} if the element might be in the Bloom filter, {@code false} if it is definitely not
+     */
     public boolean contains(T key) {
         for (Hash<T> hash : hashFunctions) {
-            int position = hash.compute(key) % bitArray.size();
+            int position = Math.abs(hash.compute(key) % bitArray.size());
             if (!bitArray.get(position)) {
                 return false;
             }
@@ -38,24 +64,46 @@ public boolean contains(T key) {
         return true;
     }
 
-    private class Hash<T> {
+    /**
+     * Inner class representing a hash function used by the Bloom filter.
+     *
+     * @param <T> The type of elements to be hashed.
+     */
+    private static class Hash<T> {
 
-        int index;
+        private final int index;
 
+        /**
+         * Constructs a Hash function with a specified index.
+         *
+         * @param index the index of this hash function
+         */
         Hash(int index) {
             this.index = index;
         }
 
+        /**
+         * Computes the hash of the given key.
+         *
+         * @param key the element to hash
+         * @return the hash value
+         */
         public int compute(T key) {
             return index * asciiString(String.valueOf(key));
         }
 
+        /**
+         * Computes the ASCII value sum of the characters in a string.
+         *
+         * @param word the string to compute
+         * @return the sum of ASCII values of the characters
+         */
         private int asciiString(String word) {
-            int number = 0;
-            for (int i = 0; i < word.length(); i++) {
-                number += word.charAt(i);
+            int sum = 0;
+            for (char c : word.toCharArray()) {
+                sum += c;
             }
-            return number;
+            return sum;
         }
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java b/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java
index d6b137406827..b19801a5ad71 100644
--- a/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java
@@ -1,12 +1,19 @@
 package com.thealgorithms.datastructures.bloomfilter;
 
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 public class BloomFilterTest {
+    private BloomFilter<String> bloomFilter;
+
+    @BeforeEach
+    void setUp() {
+        bloomFilter = new BloomFilter<>(3, 100);
+    }
 
     @Test
-    public void test1() {
+    public void testIntegerContains() {
         BloomFilter<Integer> bloomFilter = new BloomFilter<>(3, 10);
         bloomFilter.insert(3);
         bloomFilter.insert(17);
@@ -16,12 +23,43 @@ public void test1() {
     }
 
     @Test
-    public void test2() {
-        BloomFilter<String> bloomFilter = new BloomFilter<>(4, 20);
+    public void testStringContains() {
         bloomFilter.insert("omar");
         bloomFilter.insert("mahamid");
 
         Assertions.assertTrue(bloomFilter.contains("omar"));
         Assertions.assertTrue(bloomFilter.contains("mahamid"));
     }
+
+    @Test
+    void testInsertAndContains() {
+        bloomFilter.insert("hello");
+        bloomFilter.insert("world");
+
+        Assertions.assertTrue(bloomFilter.contains("hello"));
+        Assertions.assertTrue(bloomFilter.contains("world"));
+        Assertions.assertFalse(bloomFilter.contains("java"));
+    }
+
+    @Test
+    void testFalsePositive() {
+        bloomFilter.insert("apple");
+        bloomFilter.insert("banana");
+
+        Assertions.assertFalse(bloomFilter.contains("grape"));
+        Assertions.assertFalse(bloomFilter.contains("orange"));
+    }
+
+    @Test
+    void testMultipleInsertions() {
+        for (int i = 0; i < 100; i++) {
+            bloomFilter.insert("key" + i);
+        }
+
+        for (int i = 0; i < 100; i++) {
+            Assertions.assertTrue(bloomFilter.contains("key" + i));
+        }
+
+        Assertions.assertFalse(bloomFilter.contains("key" + 200));
+    }
 }

From 046f5a4728267f835299d6a65a2e88c2294975f6 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 15 Aug 2024 10:43:47 +0200
Subject: [PATCH 0275/1338] refactor: `atoi` (#5324)

---
 .../com/thealgorithms/strings/MyAtoi.java     | 103 ++++++++----------
 .../com/thealgorithms/strings/MyAtoiTest.java |  36 +++---
 2 files changed, 64 insertions(+), 75 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/MyAtoi.java b/src/main/java/com/thealgorithms/strings/MyAtoi.java
index f58ab1acf8c5..5a7c2ce53b1c 100644
--- a/src/main/java/com/thealgorithms/strings/MyAtoi.java
+++ b/src/main/java/com/thealgorithms/strings/MyAtoi.java
@@ -1,76 +1,65 @@
-// Implement the myAtoi(string s) function, which converts a string to a 32-bit signed integer
-// (similar to C/C++'s atoi function). Here is my implementation
-
 package com.thealgorithms.strings;
 
+/**
+ * A utility class that provides a method to convert a string to a 32-bit signed integer (similar to C/C++'s atoi function).
+ */
 public final class MyAtoi {
     private MyAtoi() {
     }
-    public static int myAtoi(String s) {
-        s = s.trim();
-        char[] char1 = s.toCharArray();
-        String number = "";
-        boolean negative = false;
-        boolean zero = false;
-        boolean isDigit = false;
 
-        for (char ch : char1) {
-            if (Character.isDigit(ch)) {
-                if (number.length() > 1 && !isDigit) {
-                    number = "0";
-                    break;
-                }
-                isDigit = true;
-                if (zero) {
-                    number = "0";
-                    break;
-                }
-                if (ch >= '0' && ch <= '9') {
-                    number += ch;
-                }
-            } else if (ch == '-' && !isDigit) {
-                number += "0";
-                negative = true;
-            } else if (ch == '+' && !isDigit) {
-                number += "0";
-            } else if (ch == '.' && isDigit) {
-                break;
-            } else if (ch == '.') {
-                zero = true;
-            } else {
-                if (!isDigit) {
-                    number = "0";
-                }
-                break;
-            }
+    /**
+     * Converts the given string to a 32-bit signed integer.
+     * The conversion discards any leading whitespace characters until the first non-whitespace character is found.
+     * Then, it takes an optional initial plus or minus sign followed by as many numerical digits as possible and interprets them as a numerical value.
+     * The string can contain additional characters after those that form the integral number, which are ignored and have no effect on the behavior of this function.
+     *
+     * If the number is out of the range of a 32-bit signed integer:
+     * - Returns {@code Integer.MAX_VALUE} if the value exceeds {@code Integer.MAX_VALUE}.
+     * - Returns {@code Integer.MIN_VALUE} if the value is less than {@code Integer.MIN_VALUE}.
+     *
+     * If no valid conversion could be performed, a zero is returned.
+     *
+     * @param s the string to convert
+     * @return the converted integer, or 0 if the string cannot be converted to a valid integer
+     */
+    public static int myAtoi(String s) {
+        if (s == null || s.isEmpty()) {
+            return 0;
         }
 
-        if (!isDigit) {
+        s = s.trim();
+        int length = s.length();
+        if (length == 0) {
             return 0;
         }
 
-        number = number.replaceFirst("^0+(?!$)", "");
+        int index = 0;
+        boolean negative = false;
+
+        // Check for the sign
+        if (s.charAt(index) == '-' || s.charAt(index) == '+') {
+            negative = s.charAt(index) == '-';
+            index++;
+        }
 
-        if (number.length() > 10 && negative) {
-            return -2147483648;
-        } else if (number.length() > 10) {
-            return 2147483647;
-        } else if (number.length() == 10 && negative) {
-            double db1 = Double.parseDouble(number);
-            if (db1 >= 2147483648d) {
-                return -2147483648;
+        int number = 0;
+        while (index < length) {
+            char ch = s.charAt(index);
+            if (!Character.isDigit(ch)) {
+                break;
             }
-        } else if (number.length() == 10) {
-            double db1 = Double.parseDouble(number);
-            if (db1 > (2147483647)) {
-                return 2147483647;
+
+            int digit = ch - '0';
+
+            // Check for overflow
+            if (number > (Integer.MAX_VALUE - digit) / 10) {
+                return negative ? Integer.MIN_VALUE : Integer.MAX_VALUE;
             }
-        }
 
-        if (negative) {
-            return Integer.parseInt(number) * -1;
+            number = number * 10 + digit;
+            index++;
         }
 
-        return Integer.parseInt(number);
+        return negative ? -number : number;
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/MyAtoiTest.java b/src/test/java/com/thealgorithms/strings/MyAtoiTest.java
index 45f9158571e9..8d2354910e2a 100644
--- a/src/test/java/com/thealgorithms/strings/MyAtoiTest.java
+++ b/src/test/java/com/thealgorithms/strings/MyAtoiTest.java
@@ -3,41 +3,41 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class MyAtoiTest {
 
-    @Test
-    void testOne() {
-        assertEquals(42, MyAtoi.myAtoi("42"));
-    }
-
-    @Test
-    void testTwo() {
-        assertEquals(-42, MyAtoi.myAtoi("   -42"));
+    @ParameterizedTest
+    @CsvSource({"'42', 42", "'   -42', -42", "'4193 with words', 4193", "'words and 987', 0", "'-91283472332', -2147483648", "'21474836460', 2147483647", "'   +123', 123", "'', 0", "'    ', 0", "'-2147483648', -2147483648", "'+2147483647', 2147483647", "'   -0012a42', -12",
+        "'9223372036854775808', 2147483647", "'-9223372036854775809', -2147483648", "'3.14159', 3", "'  -0012', -12", "'  0000000000012345678', 12345678", "'  -0000000000012345678', -12345678", "'  +0000000000012345678', 12345678", "'0', 0", "'+0', 0", "'-0', 0"})
+    void
+    testMyAtoi(String input, int expected) {
+        assertEquals(expected, MyAtoi.myAtoi(input));
     }
 
     @Test
-    void testThree() {
-        assertEquals(4193, MyAtoi.myAtoi("4193 with words"));
+    void testNullInput() {
+        assertEquals(0, MyAtoi.myAtoi(null));
     }
 
     @Test
-    void testFour() {
-        assertEquals(0, MyAtoi.myAtoi("0"));
+    void testSinglePlus() {
+        assertEquals(0, MyAtoi.myAtoi("+"));
     }
 
     @Test
-    void testFive() {
-        assertEquals(5678, MyAtoi.myAtoi("5678"));
+    void testSingleMinus() {
+        assertEquals(0, MyAtoi.myAtoi("-"));
     }
 
     @Test
-    void testSix() {
-        assertEquals(42, MyAtoi.myAtoi("+42"));
+    void testIntegerMinBoundary() {
+        assertEquals(Integer.MIN_VALUE, MyAtoi.myAtoi("-2147483648"));
     }
 
     @Test
-    void testSeven() {
-        assertEquals(0, MyAtoi.myAtoi("  +0   "));
+    void testIntegerMaxBoundary() {
+        assertEquals(Integer.MAX_VALUE, MyAtoi.myAtoi("2147483647"));
     }
 }

From a84a4a29ed64c6e701859339d0c69d1cd5d4982c Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 15 Aug 2024 10:48:23 +0200
Subject: [PATCH 0276/1338] refactor: cleanup `InsertionSort` (#5322)

---
 .../thealgorithms/sorts/InsertionSort.java    | 97 +++++++++----------
 1 file changed, 47 insertions(+), 50 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/InsertionSort.java b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
index 36aba615ba94..21ebf3827b5f 100644
--- a/src/main/java/com/thealgorithms/sorts/InsertionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
@@ -1,27 +1,43 @@
 package com.thealgorithms.sorts;
 
-import java.util.function.Function;
-
 class InsertionSort implements SortAlgorithm {
 
     /**
-     * Generic insertion sort algorithm in increasing order.
+     * Sorts the given array using the standard Insertion Sort algorithm.
      *
-     * @param array the array to be sorted.
-     * @param <T>   the class of array.
-     * @return sorted array.
+     * @param array The array to be sorted
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @return The sorted array
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
         return sort(array, 0, array.length);
     }
 
-    public <T extends Comparable<T>> T[] sort(T[] array, int lo, int hi) {
-        for (int i = lo; i < hi; i++) {
-            for (int j = i; j > lo && SortUtils.less(array[j], array[j - 1]); j--) {
-                SortUtils.swap(array, j, j - 1);
+    /**
+     * Sorts a subarray of the given array using the standard Insertion Sort algorithm.
+     *
+     * @param array The array to be sorted
+     * @param lo    The starting index of the subarray
+     * @param hi    The ending index of the subarray (exclusive)
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @return The sorted array
+     */
+    public <T extends Comparable<T>> T[] sort(T[] array, final int lo, final int hi) {
+        if (array == null || lo >= hi) {
+            return array;
+        }
+
+        for (int i = lo + 1; i < hi; i++) {
+            final T key = array[i];
+            int j = i - 1;
+            while (j >= lo && SortUtils.less(key, array[j])) {
+                array[j + 1] = array[j];
+                j--;
             }
+            array[j + 1] = key;
         }
+
         return array;
     }
 
@@ -31,34 +47,25 @@ public <T extends Comparable<T>> T[] sort(T[] array, int lo, int hi) {
      * comparisons like `j > 0` and swaps (we can move elements on position right, until we find
      * the right position for the chosen element) on further step.
      *
-     * @param array the array to be sorted
-     * @param <T>   Generic type which extends Comparable interface.
-     * @return sorted array
+     * @param array The array to be sorted
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @return The sorted array
      */
     public <T extends Comparable<T>> T[] sentinelSort(T[] array) {
-        int minElemIndex = 0;
-        int n = array.length;
-        if (n < 1) {
+        if (array == null || array.length <= 1) {
             return array;
         }
 
-        // put the smallest element to the 0 position as a sentinel, which will allow us to avoid
-        // redundant comparisons like `j > 0` further
-        for (int i = 1; i < n; i++) {
-            if (SortUtils.less(array[i], array[minElemIndex])) {
-                minElemIndex = i;
-            }
-        }
+        final int minElemIndex = findMinIndex(array);
         SortUtils.swap(array, 0, minElemIndex);
 
-        for (int i = 2; i < n; i++) {
+        for (int i = 2; i < array.length; i++) {
+            final T currentValue = array[i];
             int j = i;
-            T currentValue = array[i];
-            while (SortUtils.less(currentValue, array[j - 1])) {
+            while (j > 0 && SortUtils.less(currentValue, array[j - 1])) {
                 array[j] = array[j - 1];
                 j--;
             }
-
             array[j] = currentValue;
         }
 
@@ -66,29 +73,19 @@ public <T extends Comparable<T>> T[] sentinelSort(T[] array) {
     }
 
     /**
-     * Driver Code
+     * Finds the index of the minimum element in the array.
+     *
+     * @param array The array to be searched
+     * @param <T>   The type of elements in the array, which must be comparable
+     * @return The index of the minimum element
      */
-    public static void main(String[] args) {
-        int size = 100_000;
-        Double[] randomArray = SortUtilsRandomGenerator.generateArray(size);
-        Double[] copyRandomArray = new Double[size];
-        System.arraycopy(randomArray, 0, copyRandomArray, 0, size);
-
-        InsertionSort insertionSort = new InsertionSort();
-        double insertionTime = measureApproxExecTime(insertionSort::sort, randomArray);
-        System.out.printf("Original insertion time: %5.2f  sec.%n", insertionTime);
-
-        double insertionSentinelTime = measureApproxExecTime(insertionSort::sentinelSort, copyRandomArray);
-        System.out.printf("Sentinel insertion time: %5.2f  sec.%n", insertionSentinelTime);
-
-        // ~ 1.5 time sentinel sort is faster, then classical Insertion sort implementation.
-        System.out.printf("Sentinel insertion is %f3.2 time faster than Original insertion sort%n", insertionTime / insertionSentinelTime);
-    }
-
-    private static double measureApproxExecTime(Function<Double[], Double[]> sortAlgorithm, Double[] randomArray) {
-        long start = System.currentTimeMillis();
-        sortAlgorithm.apply(randomArray);
-        long end = System.currentTimeMillis();
-        return (end - start) / 1000.0;
+    private <T extends Comparable<T>> int findMinIndex(final T[] array) {
+        int minIndex = 0;
+        for (int i = 1; i < array.length; i++) {
+            if (SortUtils.less(array[i], array[minIndex])) {
+                minIndex = i;
+            }
+        }
+        return minIndex;
     }
 }

From ec30592fcbc1ce713b4d90d087168e0d9bc8304a Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 16 Aug 2024 09:07:27 +0200
Subject: [PATCH 0277/1338] refactor: `DecimalToOctal` (#5332)

---
 .../conversions/DecimalToOctal.java           | 42 +++++++++----------
 .../conversions/DecimalToOctalTest.java       | 21 ++++++++++
 2 files changed, 42 insertions(+), 21 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/conversions/DecimalToOctalTest.java

diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java b/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java
index 4bc3a6e7af8c..75687fc589ae 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java
@@ -1,38 +1,38 @@
 package com.thealgorithms.conversions;
 
-import java.util.Scanner;
-
 /**
  * This class converts Decimal numbers to Octal Numbers
  */
 public final class DecimalToOctal {
+    private static final int OCTAL_BASE = 8;
+    private static final int INITIAL_OCTAL_VALUE = 0;
+    private static final int INITIAL_PLACE_VALUE = 1;
+
     private DecimalToOctal() {
     }
 
     /**
-     * Main Method
+     * Converts a decimal number to its octal equivalent.
      *
-     * @param args Command line Arguments
+     * @param decimal The decimal number to convert.
+     * @return The octal equivalent as an integer.
+     * @throws IllegalArgumentException if the decimal number is negative.
      */
+    public static int convertToOctal(int decimal) {
+        if (decimal < 0) {
+            throw new IllegalArgumentException("Decimal number cannot be negative.");
+        }
+
+        int octal = INITIAL_OCTAL_VALUE;
+        int placeValue = INITIAL_PLACE_VALUE;
 
-    // enter in a decimal value to get Octal output
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        int n;
-        int k;
-        int d;
-        int s = 0;
-        int c = 0;
-        System.out.print("Decimal number: ");
-        n = sc.nextInt();
-        k = n;
-        while (k != 0) {
-            d = k % 8;
-            s += d * (int) Math.pow(10, c++);
-            k /= 8;
+        while (decimal != 0) {
+            int remainder = decimal % OCTAL_BASE;
+            octal += remainder * placeValue;
+            decimal /= OCTAL_BASE;
+            placeValue *= 10;
         }
 
-        System.out.println("Octal equivalent:" + s);
-        sc.close();
+        return octal;
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/DecimalToOctalTest.java b/src/test/java/com/thealgorithms/conversions/DecimalToOctalTest.java
new file mode 100644
index 000000000000..7ff274f04800
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/DecimalToOctalTest.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class DecimalToOctalTest {
+    @ParameterizedTest
+    @CsvSource({"0, 0", "7, 7", "8, 10", "10, 12", "64, 100", "83, 123", "7026, 15562"})
+    void testConvertToOctal(int decimal, int expectedOctal) {
+        assertEquals(expectedOctal, DecimalToOctal.convertToOctal(decimal));
+    }
+
+    @Test
+    void testConvertToOctalNegativeNumber() {
+        assertThrows(IllegalArgumentException.class, () -> DecimalToOctal.convertToOctal(-10));
+    }
+}

From c20375ae0fedc2630bee75389234714e3b591259 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 16 Aug 2024 16:43:54 +0200
Subject: [PATCH 0278/1338] refactor: `BinaryToHexadecimal` (#5331)

---
 .../conversions/BinaryToHexadecimal.java      | 71 ++++++++++---------
 .../conversions/BinaryToHexadecimalTest.java  | 18 +++--
 2 files changed, 50 insertions(+), 39 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java b/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
index a19baba39715..9ff2f593fe1f 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java
@@ -1,7 +1,7 @@
 package com.thealgorithms.conversions;
 
 import java.util.HashMap;
-import java.util.Scanner;
+import java.util.Map;
 
 /**
  * Converts any Binary Number to a Hexadecimal Number
@@ -9,52 +9,55 @@
  * @author Nishita Aggarwal
  */
 public final class BinaryToHexadecimal {
+    private static final int BITS_IN_HEX_DIGIT = 4;
+    private static final int BASE_BINARY = 2;
+    private static final int BASE_DECIMAL = 10;
+    private static final int HEX_START_DECIMAL = 10;
+    private static final int HEX_END_DECIMAL = 15;
+
     private BinaryToHexadecimal() {
     }
 
     /**
-     * This method converts a binary number to a hexadecimal number.
+     * Converts a binary number to a hexadecimal number.
      *
-     * @param binary The binary number
-     * @return The hexadecimal number
+     * @param binary The binary number to convert.
+     * @return The hexadecimal representation of the binary number.
+     * @throws IllegalArgumentException If the binary number contains digits other than 0 and 1.
      */
-    static String binToHex(int binary) {
-        // hm to store hexadecimal codes for binary numbers within the range: 0000 to 1111 i.e. for
-        // decimal numbers 0 to 15
-        HashMap<Integer, String> hm = new HashMap<>();
-        // String to store hexadecimal code
-        String hex = "";
-        int i;
-        for (i = 0; i < 10; i++) {
-            hm.put(i, String.valueOf(i));
-        }
-        for (i = 10; i < 16; i++) {
-            hm.put(i, String.valueOf((char) ('A' + i - 10)));
-        }
-        int currbit;
+    public static String binToHex(int binary) {
+        Map<Integer, String> hexMap = initializeHexMap();
+        StringBuilder hex = new StringBuilder();
+
         while (binary != 0) {
-            int code4 = 0; // to store decimal equivalent of number formed by 4 decimal digits
-            for (i = 0; i < 4; i++) {
-                currbit = binary % 10;
-                binary = binary / 10;
-                code4 += currbit * (int) Math.pow(2, i);
+            int decimalValue = 0;
+            for (int i = 0; i < BITS_IN_HEX_DIGIT; i++) {
+                int currentBit = binary % BASE_DECIMAL;
+                if (currentBit > 1) {
+                    throw new IllegalArgumentException("Incorrect binary digit: " + currentBit);
+                }
+                binary /= BASE_DECIMAL;
+                decimalValue += (int) (currentBit * Math.pow(BASE_BINARY, i));
             }
-            hex = hm.get(code4) + hex;
+            hex.insert(0, hexMap.get(decimalValue));
         }
-        return hex;
+
+        return !hex.isEmpty() ? hex.toString() : "0";
     }
 
     /**
-     * Main method
+     * Initializes the hexadecimal map with decimal to hexadecimal mappings.
      *
-     * @param args Command line arguments
+     * @return The initialized map containing mappings from decimal numbers to hexadecimal digits.
      */
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        System.out.println("Enter binary number:");
-        int binary = sc.nextInt();
-        String hex = binToHex(binary);
-        System.out.println("Hexadecimal Code:" + hex);
-        sc.close();
+    private static Map<Integer, String> initializeHexMap() {
+        Map<Integer, String> hexMap = new HashMap<>();
+        for (int i = 0; i < BASE_DECIMAL; i++) {
+            hexMap.put(i, String.valueOf(i));
+        }
+        for (int i = HEX_START_DECIMAL; i <= HEX_END_DECIMAL; i++) {
+            hexMap.put(i, String.valueOf((char) ('A' + i - HEX_START_DECIMAL)));
+        }
+        return hexMap;
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java b/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java
index 5cbdf39acb27..0935701e3c32 100644
--- a/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java
@@ -1,14 +1,22 @@
 package com.thealgorithms.conversions;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class BinaryToHexadecimalTest {
 
-    @Test
-    public void testBinaryToHexadecimal() {
-        assertEquals("6A", BinaryToHexadecimal.binToHex(1101010));
-        assertEquals("C", BinaryToHexadecimal.binToHex(1100));
+    @ParameterizedTest
+    @CsvSource({"0, 0", "1, 1", "10, 2", "1111, F", "1101010, 6A", "1100, C"})
+    void testBinToHex(int binary, String expectedHex) {
+        assertEquals(expectedHex, BinaryToHexadecimal.binToHex(binary));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"2", "1234", "11112"})
+    void testInvalidBinaryInput(int binary) {
+        assertThrows(IllegalArgumentException.class, () -> BinaryToHexadecimal.binToHex(binary));
     }
 }

From e32cab3189a195a25fe5eeb4089d807ec7d2b7d7 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 16 Aug 2024 16:48:47 +0200
Subject: [PATCH 0279/1338] refactor: `BinaryToDecimal` (#5330)

---
 .../conversions/BinaryToDecimal.java          | 42 +++++++++----------
 .../conversions/BinaryToDecimalTest.java      |  9 ++++
 2 files changed, 28 insertions(+), 23 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java b/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
index 67b815ab6466..36c0790e565f 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
@@ -1,37 +1,33 @@
 package com.thealgorithms.conversions;
 
-import java.util.Scanner;
-
 /**
  * This class converts a Binary number to a Decimal number
  */
 final class BinaryToDecimal {
-    private BinaryToDecimal() {
-    }
+    private static final int BINARY_BASE = 2;
 
-    public static long binaryToDecimal(long binNum) {
-        long binCopy;
-        long d;
-        long s = 0;
-        long power = 0;
-        binCopy = binNum;
-        while (binCopy != 0) {
-            d = binCopy % 10;
-            s += d * (long) Math.pow(2, power++);
-            binCopy /= 10;
-        }
-        return s;
+    private BinaryToDecimal() {
     }
 
     /**
-     * Main Method
+     * Converts a binary number to its decimal equivalent.
      *
-     * @param args Command line arguments
+     * @param binaryNumber The binary number to convert.
+     * @return The decimal equivalent of the binary number.
+     * @throws IllegalArgumentException If the binary number contains digits other than 0 and 1.
      */
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        System.out.print("Binary number: ");
-        System.out.println("Decimal equivalent:" + binaryToDecimal(sc.nextLong()));
-        sc.close();
+    public static long binaryToDecimal(long binaryNumber) {
+        long decimalValue = 0;
+        long power = 0;
+
+        while (binaryNumber != 0) {
+            long digit = binaryNumber % 10;
+            if (digit > 1) {
+                throw new IllegalArgumentException("Incorrect binary digit: " + digit);
+            }
+            decimalValue += (long) (digit * Math.pow(BINARY_BASE, power++));
+            binaryNumber /= 10;
+        }
+        return decimalValue;
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java b/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java
index 2471f919a845..9045d100285e 100644
--- a/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java
@@ -1,8 +1,11 @@
 package com.thealgorithms.conversions;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class BinaryToDecimalTest {
 
@@ -30,4 +33,10 @@ public void testLargeBinaryToDecimal() {
         assertEquals(262144L, BinaryToDecimal.binaryToDecimal(1000000000000000000L));
         assertEquals(524287L, BinaryToDecimal.binaryToDecimal(1111111111111111111L));
     }
+
+    @ParameterizedTest
+    @CsvSource({"2", "1234", "11112", "101021"})
+    void testNotCorrectBinaryInput(long binaryNumber) {
+        assertThrows(IllegalArgumentException.class, () -> BinaryToDecimal.binaryToDecimal(binaryNumber));
+    }
 }

From 98bee26d511399a0a3545bd54fd45bcf59113d1c Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 16 Aug 2024 16:55:42 +0200
Subject: [PATCH 0280/1338] refactor: `Dijkstra algorithm` (#5329)

---
 .../graphs/DIJSKSTRAS_ALGORITHM.java          | 86 ------------------
 .../graphs/DijkstraAlgorithm.java             | 91 +++++++++++++++++++
 .../graphs/DijkstraAlgorithmTest.java         | 64 +++++++++++++
 3 files changed, 155 insertions(+), 86 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
 create mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java b/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
deleted file mode 100644
index 419da4a9be73..000000000000
--- a/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java
+++ /dev/null
@@ -1,86 +0,0 @@
-/*
-Refer https://www.geeksforgeeks.org/dijkstras-shortest-path-algorithm-greedy-algo-7/
-for better understanding
- */
-package com.thealgorithms.datastructures.graphs;
-
-class Dijkstras {
-
-    int k = 9;
-
-    int minDist(int[] dist, Boolean[] set) {
-        int min = Integer.MAX_VALUE;
-        int minIndex = -1;
-
-        for (int r = 0; r < k; r++) {
-            if (!set[r] && dist[r] <= min) {
-                min = dist[r];
-                minIndex = r;
-            }
-        }
-
-        return minIndex;
-    }
-
-    void print(int[] dist) {
-        System.out.println("Vertex \t\t Distance");
-        for (int i = 0; i < k; i++) {
-            System.out.println(i + " \t " + dist[i]);
-        }
-    }
-
-    void dijkstra(int[][] graph, int src) {
-        int[] dist = new int[k];
-        Boolean[] set = new Boolean[k];
-
-        for (int i = 0; i < k; i++) {
-            dist[i] = Integer.MAX_VALUE;
-            set[i] = Boolean.FALSE;
-        }
-
-        dist[src] = 0;
-
-        for (int c = 0; c < k - 1; c++) {
-            int u = minDist(dist, set);
-
-            set[u] = Boolean.TRUE;
-
-            for (int v = 0; v < k; v++) {
-                if (!set[v] && graph[u][v] != 0 && dist[u] != Integer.MAX_VALUE && dist[u] + graph[u][v] < dist[v]) {
-                    dist[v] = dist[u] + graph[u][v];
-                }
-            }
-        }
-
-        print(dist);
-    }
-
-    public static void main(String[] args) {
-        int[][] graph = new int[][] {
-            {0, 4, 0, 0, 0, 0, 0, 8, 0},
-            {4, 0, 8, 0, 0, 0, 0, 11, 0},
-            {0, 8, 0, 7, 0, 4, 0, 0, 2},
-            {0, 0, 7, 0, 9, 14, 0, 0, 0},
-            {0, 0, 0, 9, 0, 10, 0, 0, 0},
-            {0, 0, 4, 14, 10, 0, 2, 0, 0},
-            {0, 0, 0, 0, 0, 2, 0, 1, 6},
-            {8, 11, 0, 0, 0, 0, 1, 0, 7},
-            {0, 0, 2, 0, 0, 0, 6, 7, 0},
-        };
-        Dijkstras t = new Dijkstras();
-        t.dijkstra(graph, 0);
-    } // main
-} // djikstras
-/*
-OUTPUT :
-Vertex   Distance
-0            0
-1            4
-2            12
-3            19
-4            21
-5            11
-6            9
-7            8
-8            14
- */
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java
new file mode 100644
index 000000000000..70699a9461f7
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java
@@ -0,0 +1,91 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.Arrays;
+
+/**
+ * Dijkstra's algorithm for finding the shortest path from a single source vertex to all other vertices in a graph.
+ */
+public class DijkstraAlgorithm {
+
+    private final int vertexCount;
+
+    /**
+     * Constructs a Dijkstra object with the given number of vertices.
+     *
+     * @param vertexCount The number of vertices in the graph.
+     */
+    public DijkstraAlgorithm(int vertexCount) {
+        this.vertexCount = vertexCount;
+    }
+
+    /**
+     * Executes Dijkstra's algorithm on the provided graph to find the shortest paths from the source vertex to all other vertices.
+     *
+     * The graph is represented as an adjacency matrix where {@code graph[i][j]} represents the weight of the edge from vertex {@code i}
+     * to vertex {@code j}. A value of 0 indicates no edge exists between the vertices.
+     *
+     * @param graph The graph represented as an adjacency matrix.
+     * @param source The source vertex.
+     * @return An array where the value at each index {@code i} represents the shortest distance from the source vertex to vertex {@code i}.
+     * @throws IllegalArgumentException if the source vertex is out of range.
+     */
+    public int[] run(int[][] graph, int source) {
+        if (source < 0 || source >= vertexCount) {
+            throw new IllegalArgumentException("Incorrect source");
+        }
+
+        int[] distances = new int[vertexCount];
+        boolean[] processed = new boolean[vertexCount];
+
+        Arrays.fill(distances, Integer.MAX_VALUE);
+        Arrays.fill(processed, false);
+        distances[source] = 0;
+
+        for (int count = 0; count < vertexCount - 1; count++) {
+            int u = getMinDistanceVertex(distances, processed);
+            processed[u] = true;
+
+            for (int v = 0; v < vertexCount; v++) {
+                if (!processed[v] && graph[u][v] != 0 && distances[u] != Integer.MAX_VALUE && distances[u] + graph[u][v] < distances[v]) {
+                    distances[v] = distances[u] + graph[u][v];
+                }
+            }
+        }
+
+        printDistances(distances);
+        return distances;
+    }
+
+    /**
+     * Finds the vertex with the minimum distance value from the set of vertices that have not yet been processed.
+     *
+     * @param distances The array of current shortest distances from the source vertex.
+     * @param processed The array indicating whether each vertex has been processed.
+     * @return The index of the vertex with the minimum distance value.
+     */
+    private int getMinDistanceVertex(int[] distances, boolean[] processed) {
+        int min = Integer.MAX_VALUE;
+        int minIndex = -1;
+
+        for (int v = 0; v < vertexCount; v++) {
+            if (!processed[v] && distances[v] <= min) {
+                min = distances[v];
+                minIndex = v;
+            }
+        }
+
+        return minIndex;
+    }
+
+    /**
+     * Prints the shortest distances from the source vertex to all other vertices.
+     *
+     * @param distances The array of shortest distances.
+     */
+    private void printDistances(int[] distances) {
+        System.out.println("Vertex \t Distance");
+        for (int i = 0; i < vertexCount; i++) {
+            System.out.println(i + " \t " + distances[i]);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java
new file mode 100644
index 000000000000..c5df9acdf33b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java
@@ -0,0 +1,64 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class DijkstraAlgorithmTest {
+
+    private DijkstraAlgorithm dijkstraAlgorithm;
+    private int[][] graph;
+
+    @BeforeEach
+    void setUp() {
+        graph = new int[][] {
+            {0, 4, 0, 0, 0, 0, 0, 8, 0},
+            {4, 0, 8, 0, 0, 0, 0, 11, 0},
+            {0, 8, 0, 7, 0, 4, 0, 0, 2},
+            {0, 0, 7, 0, 9, 14, 0, 0, 0},
+            {0, 0, 0, 9, 0, 10, 0, 0, 0},
+            {0, 0, 4, 14, 10, 0, 2, 0, 0},
+            {0, 0, 0, 0, 0, 2, 0, 1, 6},
+            {8, 11, 0, 0, 0, 0, 1, 0, 7},
+            {0, 0, 2, 0, 0, 0, 6, 7, 0},
+        };
+
+        dijkstraAlgorithm = new DijkstraAlgorithm(graph.length);
+    }
+
+    @Test
+    void testRunAlgorithm() {
+        int[] expectedDistances = {0, 4, 12, 19, 21, 11, 9, 8, 14};
+        assertArrayEquals(expectedDistances, dijkstraAlgorithm.run(graph, 0));
+    }
+
+    @Test
+    void testGraphWithDisconnectedNodes() {
+        int[][] disconnectedGraph = {
+            {0, 3, 0, 0}, {3, 0, 1, 0}, {0, 1, 0, 0}, {0, 0, 0, 0} // Node 3 is disconnected
+        };
+
+        DijkstraAlgorithm dijkstraDisconnected = new DijkstraAlgorithm(disconnectedGraph.length);
+
+        // Testing from vertex 0
+        int[] expectedDistances = {0, 3, 4, Integer.MAX_VALUE}; // Node 3 is unreachable
+        assertArrayEquals(expectedDistances, dijkstraDisconnected.run(disconnectedGraph, 0));
+    }
+
+    @Test
+    void testSingleVertexGraph() {
+        int[][] singleVertexGraph = {{0}};
+        DijkstraAlgorithm dijkstraSingleVertex = new DijkstraAlgorithm(1);
+
+        int[] expectedDistances = {0}; // The only vertex's distance to itself is 0
+        assertArrayEquals(expectedDistances, dijkstraSingleVertex.run(singleVertexGraph, 0));
+    }
+
+    @Test
+    void testInvalidSourceVertex() {
+        assertThrows(IllegalArgumentException.class, () -> dijkstraAlgorithm.run(graph, -1));
+        assertThrows(IllegalArgumentException.class, () -> dijkstraAlgorithm.run(graph, graph.length));
+    }
+}

From 7c58b190c8ebd375cb87f873e0acfdc21282d7e8 Mon Sep 17 00:00:00 2001
From: mountdisk <mountdisk@icloud.com>
Date: Sat, 17 Aug 2024 01:19:15 +0800
Subject: [PATCH 0281/1338] chore: fix some comments (#5333)

---
 .../com/thealgorithms/backtracking/ParenthesesGenerator.java    | 2 +-
 .../com/thealgorithms/datastructures/trees/BSTRecursive.java    | 2 +-
 src/main/java/com/thealgorithms/misc/PalindromePrime.java       | 2 +-
 .../java/com/thealgorithms/searches/HowManyTimesRotated.java    | 2 +-
 src/test/java/com/thealgorithms/maths/FFTTest.java              | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java b/src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java
index 8bbed4106251..bf93f946ab7b 100644
--- a/src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java
+++ b/src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java
@@ -19,7 +19,7 @@ private ParenthesesGenerator() {
      */
     public static List<String> generateParentheses(final int n) {
         if (n < 0) {
-            throw new IllegalArgumentException("The number of pairs of parentheses cannot be nagative");
+            throw new IllegalArgumentException("The number of pairs of parentheses cannot be negative");
         }
         List<String> result = new ArrayList<>();
         generateParenthesesHelper(result, "", 0, 0, n);
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursive.java b/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursive.java
index 4e24f4bfb32a..6c1f4f672ff0 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursive.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursive.java
@@ -95,7 +95,7 @@ private Node insert(Node node, int data) {
     }
 
     /**
-     * Serach recursively if the given value is present in BST or not.
+     * Search recursively if the given value is present in BST or not.
      *
      * @param node the current node to check
      * @param data the value to be checked
diff --git a/src/main/java/com/thealgorithms/misc/PalindromePrime.java b/src/main/java/com/thealgorithms/misc/PalindromePrime.java
index 6b01cdced23c..e1cbf3ff839a 100644
--- a/src/main/java/com/thealgorithms/misc/PalindromePrime.java
+++ b/src/main/java/com/thealgorithms/misc/PalindromePrime.java
@@ -6,7 +6,7 @@ public final class PalindromePrime {
     private PalindromePrime() {
     }
 
-    public static void main(String[] args) { // Main funtion
+    public static void main(String[] args) { // Main function
         Scanner in = new Scanner(System.in);
         System.out.println("Enter the quantity of First Palindromic Primes you want");
         int n = in.nextInt(); // Input of how many first palindromic prime we want
diff --git a/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java b/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java
index 8e601f9873b3..dd01378f4d5f 100644
--- a/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java
+++ b/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java
@@ -17,7 +17,7 @@
     from its initial sorted position.
     Eg. For [2,5,6,8,11,12,15,18], 1 rotation gives [5,6,8,11,12,15,18,2], 2 rotations
    [6,8,11,12,15,18,2,5] and so on. Finding the minimum element will take O(N) time but, we can  use
-   Binary Search to find the mimimum element, we can reduce the complexity to O(log N). If we look
+   Binary Search to find the minimum element, we can reduce the complexity to O(log N). If we look
    at the rotated array, to identify the minimum element (say a[i]), we observe that
    a[i-1]>a[i]<a[i+1].
 
diff --git a/src/test/java/com/thealgorithms/maths/FFTTest.java b/src/test/java/com/thealgorithms/maths/FFTTest.java
index 696ab5a24732..8d78fb0f2a16 100644
--- a/src/test/java/com/thealgorithms/maths/FFTTest.java
+++ b/src/test/java/com/thealgorithms/maths/FFTTest.java
@@ -40,7 +40,7 @@ void addFalseTest() {
         assertNotEquals(2.0, add);
     }
 
-    // Testing the function substract, assertEqual test
+    // Testing the function subtract, assertEqual test
     @Test
     void subtractTest() {
         FFT.Complex complex1 = new FFT.Complex(2.0, 2.0);

From d80fd0c623306ad14bb76a02328e812e435725d2 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 17 Aug 2024 20:35:36 +0200
Subject: [PATCH 0282/1338] refactor: `DecimalToBinary` (#5339)

---
 .../conversions/DecimalToBinary.java          | 76 ++++++++-----------
 .../conversions/DecimalToBinaryTest.java      | 21 +++++
 2 files changed, 52 insertions(+), 45 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/conversions/DecimalToBinaryTest.java

diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java b/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java
index 471724ff9966..e8d033e0093c 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java
@@ -1,63 +1,49 @@
 package com.thealgorithms.conversions;
 
-import java.util.Scanner;
-
 /**
- * This class converts a Decimal number to a Binary number
+ * This class provides methods to convert a decimal number to a binary number.
  */
 final class DecimalToBinary {
+    private static final int BINARY_BASE = 2;
+    private static final int DECIMAL_MULTIPLIER = 10;
+
     private DecimalToBinary() {
     }
 
     /**
-     * Main Method
-     *
-     * @param args Command Line Arguments
+     * Converts a decimal number to a binary number using a conventional algorithm.
+     * @param decimalNumber the decimal number to convert
+     * @return the binary representation of the decimal number
      */
-    public static void main(String[] args) {
-        conventionalConversion();
-        bitwiseConversion();
-    }
+    public static int convertUsingConventionalAlgorithm(int decimalNumber) {
+        int binaryNumber = 0;
+        int position = 1;
 
-    /**
-     * This method converts a decimal number to a binary number using a
-     * conventional algorithm.
-     */
-    public static void conventionalConversion() {
-        int n;
-        int b = 0;
-        int c = 0;
-        int d;
-        Scanner input = new Scanner(System.in);
-        System.out.printf("Conventional conversion.%n Enter the decimal number: ");
-        n = input.nextInt();
-        while (n != 0) {
-            d = n % 2;
-            b = b + d * (int) Math.pow(10, c++);
-            n /= 2;
-        } // converting decimal to binary
-        System.out.println("\tBinary number: " + b);
-        input.close();
+        while (decimalNumber > 0) {
+            int remainder = decimalNumber % BINARY_BASE;
+            binaryNumber += remainder * position;
+            position *= DECIMAL_MULTIPLIER;
+            decimalNumber /= BINARY_BASE;
+        }
+
+        return binaryNumber;
     }
 
     /**
-     * This method converts a decimal number to a binary number using a bitwise
-     * algorithm
+     * Converts a decimal number to a binary number using a bitwise algorithm.
+     * @param decimalNumber the decimal number to convert
+     * @return the binary representation of the decimal number
      */
-    public static void bitwiseConversion() {
-        int n;
-        int b = 0;
-        int c = 0;
-        int d;
-        Scanner input = new Scanner(System.in);
-        System.out.printf("Bitwise conversion.%n Enter the decimal number: ");
-        n = input.nextInt();
-        while (n != 0) {
-            d = (n & 1);
-            b += d * (int) Math.pow(10, c++);
-            n >>= 1;
+    public static int convertUsingBitwiseAlgorithm(int decimalNumber) {
+        int binaryNumber = 0;
+        int position = 1;
+
+        while (decimalNumber > 0) {
+            int leastSignificantBit = decimalNumber & 1;
+            binaryNumber += leastSignificantBit * position;
+            position *= DECIMAL_MULTIPLIER;
+            decimalNumber >>= 1;
         }
-        System.out.println("\tBinary number: " + b);
-        input.close();
+        return binaryNumber;
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/DecimalToBinaryTest.java b/src/test/java/com/thealgorithms/conversions/DecimalToBinaryTest.java
new file mode 100644
index 000000000000..f194951e9e64
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/DecimalToBinaryTest.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class DecimalToBinaryTest {
+
+    @ParameterizedTest
+    @CsvSource({"0, 0", "1, 1", "2, 10", "5, 101", "10, 1010", "15, 1111", "100, 1100100"})
+    void testConvertUsingConventionalAlgorithm(int decimal, int expectedBinary) {
+        assertEquals(expectedBinary, DecimalToBinary.convertUsingConventionalAlgorithm(decimal));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"0, 0", "1, 1", "2, 10", "5, 101", "10, 1010", "15, 1111", "100, 1100100"})
+    void testConvertUsingBitwiseAlgorithm(int decimal, int expectedBinary) {
+        assertEquals(expectedBinary, DecimalToBinary.convertUsingBitwiseAlgorithm(decimal));
+    }
+}

From 25b6aebe45795468f365ef9449525fcf258faffc Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 17 Aug 2024 20:58:50 +0200
Subject: [PATCH 0283/1338] refactor: `DecimalToHexadecimal` (#5337)

---
 .../conversions/DecimalToHexaDecimal.java     | 51 -------------------
 .../conversions/DecimalToHexadecimal.java     | 42 +++++++++++++++
 .../conversions/DecimalToHexaDecimalTest.java | 14 -----
 .../conversions/DecimalToHexadecimalTest.java | 14 +++++
 4 files changed, 56 insertions(+), 65 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java
 create mode 100644 src/main/java/com/thealgorithms/conversions/DecimalToHexadecimal.java
 delete mode 100644 src/test/java/com/thealgorithms/conversions/DecimalToHexaDecimalTest.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/DecimalToHexadecimalTest.java

diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java b/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java
deleted file mode 100644
index 78838c6107b7..000000000000
--- a/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java
+++ /dev/null
@@ -1,51 +0,0 @@
-package com.thealgorithms.conversions;
-
-// hex = [0 - 9] -> [A - F]
-final class DecimalToHexaDecimal {
-    private DecimalToHexaDecimal() {
-    }
-
-    private static final int SIZE_OF_INT_IN_HALF_BYTES = 8;
-    private static final int NUMBER_OF_BITS_IN_HALF_BYTE = 4;
-    private static final int HALF_BYTE = 0x0F;
-    private static final char[] HEX_DIGITS = {
-        '0',
-        '1',
-        '2',
-        '3',
-        '4',
-        '5',
-        '6',
-        '7',
-        '8',
-        '9',
-        'A',
-        'B',
-        'C',
-        'D',
-        'E',
-        'F',
-    };
-
-    // Returns the hex value of the dec entered in the parameter.
-    public static String decToHex(int dec) {
-        StringBuilder hexBuilder = new StringBuilder(SIZE_OF_INT_IN_HALF_BYTES);
-        hexBuilder.setLength(SIZE_OF_INT_IN_HALF_BYTES);
-        for (int i = SIZE_OF_INT_IN_HALF_BYTES - 1; i >= 0; --i) {
-            int j = dec & HALF_BYTE;
-            hexBuilder.setCharAt(i, HEX_DIGITS[j]);
-            dec >>= NUMBER_OF_BITS_IN_HALF_BYTE;
-        }
-        return hexBuilder.toString().toLowerCase();
-    }
-
-    // Test above function.
-    public static void main(String[] args) {
-        System.out.println("Test...");
-        int dec = 305445566;
-        String libraryDecToHex = Integer.toHexString(dec);
-        String decToHex = decToHex(dec);
-        System.out.println("Result from the library : " + libraryDecToHex);
-        System.out.println("Result decToHex method : " + decToHex);
-    }
-}
diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToHexadecimal.java b/src/main/java/com/thealgorithms/conversions/DecimalToHexadecimal.java
new file mode 100644
index 000000000000..47a1e36b27e3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToHexadecimal.java
@@ -0,0 +1,42 @@
+package com.thealgorithms.conversions;
+
+/**
+ * This class provides a method to convert a decimal number to a hexadecimal string.
+ */
+final class DecimalToHexadecimal {
+    private static final int SIZE_OF_INT_IN_HALF_BYTES = 8;
+    private static final int NUMBER_OF_BITS_IN_HALF_BYTE = 4;
+    private static final int HALF_BYTE_MASK = 0x0F;
+    private static final char[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
+
+    private DecimalToHexadecimal() {
+    }
+
+    /**
+     * Converts a decimal number to a hexadecimal string.
+     * @param decimal the decimal number to convert
+     * @return the hexadecimal representation of the decimal number
+     */
+    public static String decToHex(int decimal) {
+        StringBuilder hexBuilder = new StringBuilder(SIZE_OF_INT_IN_HALF_BYTES);
+        for (int i = SIZE_OF_INT_IN_HALF_BYTES - 1; i >= 0; --i) {
+            int currentHalfByte = decimal & HALF_BYTE_MASK;
+            hexBuilder.insert(0, HEX_DIGITS[currentHalfByte]);
+            decimal >>= NUMBER_OF_BITS_IN_HALF_BYTE;
+        }
+        return removeLeadingZeros(hexBuilder.toString().toLowerCase());
+    }
+
+    private static String removeLeadingZeros(String str) {
+        if (str == null || str.isEmpty()) {
+            return str;
+        }
+
+        int i = 0;
+        while (i < str.length() && str.charAt(i) == '0') {
+            i++;
+        }
+
+        return i == str.length() ? "0" : str.substring(i);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/DecimalToHexaDecimalTest.java b/src/test/java/com/thealgorithms/conversions/DecimalToHexaDecimalTest.java
deleted file mode 100644
index 1105f457504e..000000000000
--- a/src/test/java/com/thealgorithms/conversions/DecimalToHexaDecimalTest.java
+++ /dev/null
@@ -1,14 +0,0 @@
-package com.thealgorithms.conversions;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.api.Test;
-
-public class DecimalToHexaDecimalTest {
-
-    @Test
-    public void testDecimalToHexaDecimal() {
-        assertEquals("000000be", DecimalToHexaDecimal.decToHex(190));
-        assertEquals("00000708", DecimalToHexaDecimal.decToHex(1800));
-    }
-}
diff --git a/src/test/java/com/thealgorithms/conversions/DecimalToHexadecimalTest.java b/src/test/java/com/thealgorithms/conversions/DecimalToHexadecimalTest.java
new file mode 100644
index 000000000000..c9817b5d6926
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/DecimalToHexadecimalTest.java
@@ -0,0 +1,14 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class DecimalToHexadecimalTest {
+    @ParameterizedTest
+    @CsvSource({"0, 0", "1, 1", "10, a", "15, f", "16, 10", "255, ff", "190, be", "1800, 708"})
+    void testDecToHex(int decimal, String expectedHex) {
+        assertEquals(expectedHex, DecimalToHexadecimal.decToHex(decimal));
+    }
+}

From e8985b3edbf76adf1c6e8d6b6cb36de606ca150a Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 17 Aug 2024 21:06:45 +0200
Subject: [PATCH 0284/1338] refactor: `BinaryToOctal` (#5338)

* refactor: BinaryToOctal

* checkstyle: fix formatting

* refactor: adding input correctness case, cover by tests. Renaming variable

---------

Co-authored-by: alxkm <alx@alx.com>
Co-authored-by: Bama Charan Chhandogi <b.c.chhandogi@gmail.com>
---
 .../conversions/BinaryToOctal.java            | 59 +++++++++----------
 .../conversions/BinaryToOctalTest.java        | 16 ++++-
 2 files changed, 40 insertions(+), 35 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java b/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java
index 6fef090287ab..5407c8525a23 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java
@@ -1,27 +1,11 @@
 package com.thealgorithms.conversions;
 
-import java.util.Scanner;
-
-/**
- * Converts any Binary number to an Octal Number
- *
- * @author Zachary Jones
- */
 public final class BinaryToOctal {
-    private BinaryToOctal() {
-    }
+    private static final int BITS_PER_OCTAL_DIGIT = 3;
+    private static final int BINARY_BASE = 2;
+    private static final int DECIMAL_BASE = 10;
 
-    /**
-     * Main method
-     *
-     * @param args Command line arguments
-     */
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        System.out.println("Input the binary number: ");
-        int b = sc.nextInt();
-        System.out.println("Octal equivalent: " + convertBinaryToOctal(b));
-        sc.close();
+    private BinaryToOctal() {
     }
 
     /**
@@ -29,22 +13,33 @@ public static void main(String[] args) {
      *
      * @param binary The binary number
      * @return The octal number
+     * @throws IllegalArgumentException if the input is not a valid binary number
      */
     public static String convertBinaryToOctal(int binary) {
-        String octal = "";
-        int currBit = 0;
-        int j = 1;
+        if (binary == 0) {
+            return "0";
+        }
+
+        if (!String.valueOf(binary).matches("[01]+")) {
+            throw new IllegalArgumentException("Input is not a valid binary number.");
+        }
+
+        StringBuilder octal = new StringBuilder();
+        int currentBit;
+        int bitValueMultiplier = 1;
+
         while (binary != 0) {
-            int code3 = 0;
-            for (int i = 0; i < 3; i++) {
-                currBit = binary % 10;
-                binary = binary / 10;
-                code3 += currBit * j;
-                j *= 2;
+            int octalDigit = 0;
+            for (int i = 0; i < BITS_PER_OCTAL_DIGIT && binary != 0; i++) {
+                currentBit = binary % DECIMAL_BASE;
+                binary /= DECIMAL_BASE;
+                octalDigit += currentBit * bitValueMultiplier;
+                bitValueMultiplier *= BINARY_BASE;
             }
-            octal = code3 + octal;
-            j = 1;
+            octal.insert(0, octalDigit);
+            bitValueMultiplier = 1; // Reset multiplier for the next group
         }
-        return octal;
+
+        return octal.toString();
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java b/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java
index c7018daecf23..98bd55a3d6c9 100644
--- a/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java
@@ -1,14 +1,24 @@
 package com.thealgorithms.conversions;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class BinaryToOctalTest {
 
+    @ParameterizedTest
+    @CsvSource({"0, 0", "1, 1", "10, 2", "111, 7", "1000, 10", "1111, 17", "110101, 65", "1010101, 125", "110110011, 663", "111111111, 777", "10010110, 226", "1011101, 135"})
+    void testConvertBinaryToOctal(int binary, String expectedOctal) {
+        assertEquals(expectedOctal, BinaryToOctal.convertBinaryToOctal(binary));
+    }
+
     @Test
-    public void testBinaryToOctal() {
-        assertEquals("226", BinaryToOctal.convertBinaryToOctal(10010110));
-        assertEquals("135", BinaryToOctal.convertBinaryToOctal(1011101));
+    void testIncorrectInput() {
+        assertThrows(IllegalArgumentException.class, () -> BinaryToOctal.convertBinaryToOctal(1234));
+        assertThrows(IllegalArgumentException.class, () -> BinaryToOctal.convertBinaryToOctal(102));
+        assertThrows(IllegalArgumentException.class, () -> BinaryToOctal.convertBinaryToOctal(-1010));
     }
 }

From 404ad7272f18c8e48b5c65c69e117b449ea553c6 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 17 Aug 2024 21:31:29 +0200
Subject: [PATCH 0285/1338] refactor: `Bag` data structure (#5340)

---
 .../datastructures/bags/Bag.java              | 102 +++++++---------
 .../datastructures/bag/BagTest.java           | 111 ++++++++++++++++++
 2 files changed, 153 insertions(+), 60 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/bag/BagTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/bags/Bag.java b/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
index ff5c832baeaf..1bb143fabda1 100644
--- a/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
+++ b/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
@@ -4,23 +4,23 @@
 import java.util.NoSuchElementException;
 
 /**
- * Collection which does not allow removing elements (only collect and iterate)
+ * A collection that allows adding and iterating over elements but does not support element removal.
  *
- * @param <Element> - the generic type of an element in this bag
+ * @param <E> the type of elements in this bag
  */
-public class Bag<Element> implements Iterable<Element> {
+public class Bag<E> implements Iterable<E> {
 
-    private Node<Element> firstElement; // first element of the bag
-    private int size; // size of bag
+    private Node<E> firstElement; // First element in the bag
+    private int size; // Number of elements in the bag
 
-    private static final class Node<Element> {
-
-        private Element content;
-        private Node<Element> nextElement;
+    // Node class representing each element in the bag
+    private static final class Node<E> {
+        private E content;
+        private Node<E> nextElement;
     }
 
     /**
-     * Create an empty bag
+     * Constructs an empty bag.
      */
     public Bag() {
         firstElement = null;
@@ -28,13 +28,17 @@ public Bag() {
     }
 
     /**
-     * @return true if this bag is empty, false otherwise
+     * Checks if the bag is empty.
+     *
+     * @return true if the bag is empty, false otherwise
      */
     public boolean isEmpty() {
-        return firstElement == null;
+        return size == 0;
     }
 
     /**
+     * Returns the number of elements in the bag.
+     *
      * @return the number of elements
      */
     public int size() {
@@ -42,24 +46,26 @@ public int size() {
     }
 
     /**
-     * @param element - the element to add
+     * Adds an element to the bag.
+     *
+     * @param element the element to add
      */
-    public void add(Element element) {
-        Node<Element> oldfirst = firstElement;
-        firstElement = new Node<>();
-        firstElement.content = element;
-        firstElement.nextElement = oldfirst;
+    public void add(E element) {
+        Node<E> newNode = new Node<>();
+        newNode.content = element;
+        newNode.nextElement = firstElement;
+        firstElement = newNode;
         size++;
     }
 
     /**
-     * Checks if the bag contains a specific element
+     * Checks if the bag contains a specific element.
      *
-     * @param element which you want to look for
-     * @return true if bag contains element, otherwise false
+     * @param element the element to check for
+     * @return true if the bag contains the element, false otherwise
      */
-    public boolean contains(Element element) {
-        for (Element value : this) {
+    public boolean contains(E element) {
+        for (E value : this) {
             if (value.equals(element)) {
                 return true;
             }
@@ -68,61 +74,37 @@ public boolean contains(Element element) {
     }
 
     /**
-     * @return an iterator that iterates over the elements in this bag in
-     * arbitrary order
+     * Returns an iterator over the elements in this bag.
+     *
+     * @return an iterator that iterates over the elements in the bag
      */
-    public Iterator<Element> iterator() {
+    @Override
+    public Iterator<E> iterator() {
         return new ListIterator<>(firstElement);
     }
 
-    @SuppressWarnings("hiding")
-    private class ListIterator<Element> implements Iterator<Element> {
+    // Private class for iterating over elements
+    private static class ListIterator<E> implements Iterator<E> {
 
-        private Node<Element> currentElement;
+        private Node<E> currentElement;
 
-        ListIterator(Node<Element> firstElement) {
-            currentElement = firstElement;
+        ListIterator(Node<E> firstElement) {
+            this.currentElement = firstElement;
         }
 
+        @Override
         public boolean hasNext() {
             return currentElement != null;
         }
 
-        /**
-         * remove is not allowed in a bag
-         */
         @Override
-        public void remove() {
-            throw new UnsupportedOperationException();
-        }
-
-        public Element next() {
+        public E next() {
             if (!hasNext()) {
                 throw new NoSuchElementException();
             }
-            Element element = currentElement.content;
+            E element = currentElement.content;
             currentElement = currentElement.nextElement;
             return element;
         }
     }
-
-    /**
-     * main-method for testing
-     */
-    public static void main(String[] args) {
-        Bag<String> bag = new Bag<>();
-
-        bag.add("1");
-        bag.add("1");
-        bag.add("2");
-
-        System.out.println("size of bag = " + bag.size());
-        for (String s : bag) {
-            System.out.println(s);
-        }
-
-        System.out.println(bag.contains(null));
-        System.out.println(bag.contains("1"));
-        System.out.println(bag.contains("3"));
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java b/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
new file mode 100644
index 000000000000..c0fe107bfba5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
@@ -0,0 +1,111 @@
+package com.thealgorithms.datastructures.bag;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.thealgorithms.datastructures.bags.Bag;
+import java.util.Iterator;
+import org.junit.jupiter.api.Test;
+
+class BagTest {
+
+    @Test
+    void testBagOperations() {
+        Bag<String> bag = new Bag<>();
+        assertTrue(bag.isEmpty(), "Bag should be empty initially");
+        assertEquals(0, bag.size(), "Bag size should be 0 initially");
+
+        bag.add("item1");
+        bag.add("item2");
+        bag.add("item1"); // adding duplicate item
+
+        assertFalse(bag.isEmpty(), "Bag should not be empty after adding elements");
+        assertEquals(3, bag.size(), "Bag size should be 3 after adding 3 elements");
+
+        assertTrue(bag.contains("item1"), "Bag should contain 'item1'");
+        assertTrue(bag.contains("item2"), "Bag should contain 'item2'");
+        assertFalse(bag.contains("item3"), "Bag should not contain 'item3'");
+        assertFalse(bag.contains(null), "Bag should not contain null");
+
+        // Test iteration
+        int count = 0;
+        for (String item : bag) {
+            assertTrue(item.equals("item1") || item.equals("item2"), "Item should be either 'item1' or 'item2'");
+            count++;
+        }
+        assertEquals(3, count, "Iterator should traverse all 3 items");
+    }
+
+    @Test
+    void testBagInitialization() {
+        Bag<String> bag = new Bag<>();
+        assertTrue(bag.isEmpty(), "Bag should be empty initially");
+        assertEquals(0, bag.size(), "Bag size should be 0 initially");
+    }
+
+    @Test
+    void testAddElements() {
+        Bag<String> bag = new Bag<>();
+        bag.add("item1");
+        bag.add("item2");
+        bag.add("item1"); // Adding duplicate item
+
+        assertFalse(bag.isEmpty(), "Bag should not be empty after adding elements");
+        assertEquals(3, bag.size(), "Bag size should be 3 after adding 3 elements");
+    }
+
+    @Test
+    void testContainsMethod() {
+        Bag<String> bag = new Bag<>();
+        bag.add("item1");
+        bag.add("item2");
+
+        assertTrue(bag.contains("item1"), "Bag should contain 'item1'");
+        assertTrue(bag.contains("item2"), "Bag should contain 'item2'");
+        assertFalse(bag.contains("item3"), "Bag should not contain 'item3'");
+        assertFalse(bag.contains(null), "Bag should not contain null");
+    }
+
+    @Test
+    void testContainsAfterRemoveOperation() {
+        Bag<String> bag = new Bag<>();
+        bag.add("item1");
+        bag.add("item2");
+        assertTrue(bag.contains("item1"), "Bag should contain 'item1' before removal");
+        assertTrue(bag.contains("item2"), "Bag should contain 'item2' before removal");
+    }
+
+    @Test
+    void testIterator() {
+        Bag<String> bag = new Bag<>();
+        bag.add("item1");
+        bag.add("item2");
+        bag.add("item3");
+
+        int count = 0;
+        for (String item : bag) {
+            assertTrue(item.equals("item1") || item.equals("item2") || item.equals("item3"), "Item should be one of 'item1', 'item2', or 'item3'");
+            count++;
+        }
+        assertEquals(3, count, "Iterator should traverse all 3 items");
+    }
+
+    @Test
+    void testIteratorEmptyBag() {
+        Bag<String> bag = new Bag<>();
+        int count = 0;
+        for (String ignored : bag) {
+            org.junit.jupiter.api.Assertions.fail("Iterator should not return any items for an empty bag");
+        }
+        assertEquals(0, count, "Iterator should not traverse any items in an empty bag");
+    }
+
+    @Test
+    void testRemoveMethodThrowsException() {
+        Bag<String> bag = new Bag<>();
+        bag.add("item1");
+        Iterator<String> iterator = bag.iterator();
+        org.junit.jupiter.api.Assertions.assertThrows(UnsupportedOperationException.class, iterator::remove, "Remove operation should throw UnsupportedOperationException");
+    }
+}

From 2905ccbb20806d89a34b6432a6806fb3af48ff08 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 18 Aug 2024 20:45:30 +0200
Subject: [PATCH 0286/1338] refactor: `DecimalToAnyBase` (#5343)

---
 .../conversions/DecimalToAnyBase.java         | 80 +++++++++----------
 .../conversions/DecimalToAnyBaseTest.java     | 23 ++++++
 2 files changed, 63 insertions(+), 40 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/conversions/DecimalToAnyBaseTest.java

diff --git a/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java b/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java
index 019c4026bfb5..a5615dc002f5 100644
--- a/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java
+++ b/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java
@@ -1,69 +1,69 @@
 package com.thealgorithms.conversions;
 
-import java.io.BufferedReader;
-import java.io.InputStreamReader;
 import java.util.ArrayList;
+import java.util.List;
 
 /**
+ *  Class that provides methods to convert a decimal number to a string representation
+ *  in any specified base between 2 and 36.
+ *
  * @author Varun Upadhyay (<a href="https://github.com/varunu28">...</a>)
  */
-// Driver Program
 public final class DecimalToAnyBase {
-    private DecimalToAnyBase() {
-    }
-
-    public static void main(String[] args) throws Exception {
-        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
-        System.out.println("Enter the decimal input below: ");
-        int decInput = Integer.parseInt(br.readLine());
-        System.out.println();
-
-        System.out.println("Enter the base below: ");
-        int base = Integer.parseInt(br.readLine());
-        System.out.println();
+    private static final int MIN_BASE = 2;
+    private static final int MAX_BASE = 36;
+    private static final char ZERO_CHAR = '0';
+    private static final char A_CHAR = 'A';
+    private static final int DIGIT_OFFSET = 10;
 
-        System.out.println("Decimal Input"
-            + " is: " + decInput);
-        System.out.println("Value of " + decInput + " in base " + base + " is: " + convertToAnyBase(decInput, base));
-
-        br.close();
+    private DecimalToAnyBase() {
     }
 
     /**
-     * This method produces a String value of any given input decimal in any
-     * base
+     * Converts a decimal number to a string representation in the specified base.
+     * For example, converting the decimal number 10 to base 2 would return "1010".
      *
-     * @param inp Decimal of which we need the value in base in String format
-     * @return string format of the converted value in the given base
+     * @param decimal the decimal number to convert
+     * @param base    the base to convert to (must be between {@value #MIN_BASE} and {@value #MAX_BASE})
+     * @return the string representation of the number in the specified base
+     * @throws IllegalArgumentException if the base is out of the supported range
      */
-    public static String convertToAnyBase(int inp, int base) {
-        ArrayList<Character> charArr = new ArrayList<>();
+    public static String convertToAnyBase(int decimal, int base) {
+        if (base < MIN_BASE || base > MAX_BASE) {
+            throw new IllegalArgumentException("Base must be between " + MIN_BASE + " and " + MAX_BASE);
+        }
 
-        while (inp > 0) {
-            charArr.add(reVal(inp % base));
-            inp /= base;
+        if (decimal == 0) {
+            return String.valueOf(ZERO_CHAR);
         }
 
-        StringBuilder str = new StringBuilder(charArr.size());
+        List<Character> digits = new ArrayList<>();
+        while (decimal > 0) {
+            digits.add(convertToChar(decimal % base));
+            decimal /= base;
+        }
 
-        for (Character ch : charArr) {
-            str.append(ch);
+        StringBuilder result = new StringBuilder(digits.size());
+        for (int i = digits.size() - 1; i >= 0; i--) {
+            result.append(digits.get(i));
         }
 
-        return str.reverse().toString();
+        return result.toString();
     }
 
     /**
-     * This method produces character value of the input integer and returns it
+     * Converts an integer value to its corresponding character in the specified base.
+     * This method is used to convert values from 0 to 35 into their appropriate character representation.
+     * For example, 0-9 are represented as '0'-'9', and 10-35 are represented as 'A'-'Z'.
      *
-     * @param num integer of which we need the character value of
-     * @return character value of input integer
+     * @param value the integer value to convert (should be less than the base value)
+     * @return the character representing the value in the specified base
      */
-    public static char reVal(int num) {
-        if (num >= 0 && num <= 9) {
-            return (char) (num + '0');
+    private static char convertToChar(int value) {
+        if (value >= 0 && value <= 9) {
+            return (char) (ZERO_CHAR + value);
         } else {
-            return (char) (num - 10 + 'A');
+            return (char) (A_CHAR + value - DIGIT_OFFSET);
         }
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/DecimalToAnyBaseTest.java b/src/test/java/com/thealgorithms/conversions/DecimalToAnyBaseTest.java
new file mode 100644
index 000000000000..04630b71cce4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/DecimalToAnyBaseTest.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class DecimalToAnyBaseTest {
+
+    @ParameterizedTest
+    @CsvSource({"0, 2, 0", "0, 16, 0", "0, 36, 0", "10, 2, 1010", "255, 16, FF", "100, 8, 144", "42, 2, 101010", "1234, 16, 4D2", "1234, 36, YA"})
+    void testConvertToAnyBase(int decimal, int base, String expected) {
+        assertEquals(expected, DecimalToAnyBase.convertToAnyBase(decimal, base));
+    }
+
+    @Test
+    void testBaseOutOfRange() {
+        assertThrows(IllegalArgumentException.class, () -> DecimalToAnyBase.convertToAnyBase(10, 1));
+        assertThrows(IllegalArgumentException.class, () -> DecimalToAnyBase.convertToAnyBase(10, 37));
+    }
+}

From a9f5b8270839dde00e75c73eefbefd2d17b44b47 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 18 Aug 2024 20:58:57 +0200
Subject: [PATCH 0287/1338] refactor: `OctalToDecimal` (#5344)

---
 .../conversions/OctalToDecimal.java           | 55 +++++++++----------
 .../conversions/OctalToDecimalTest.java       | 21 ++++---
 2 files changed, 39 insertions(+), 37 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java b/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java
index 187f0ed1e2ea..d91ce6eb3634 100644
--- a/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java
@@ -1,47 +1,42 @@
 package com.thealgorithms.conversions;
 
-import java.util.Scanner;
-
 /**
- * Converts any Octal Number to a Decimal Number
+ * Class for converting an octal number to a decimal number. Octal numbers are based on 8, using digits from 0 to 7.
  *
- * @author Zachary Jones
  */
 public final class OctalToDecimal {
+    private static final int OCTAL_BASE = 8;
+
     private OctalToDecimal() {
     }
 
     /**
-     * Main method
+     * Converts a given octal number (as a string) to its decimal representation.
+     * If the input is not a valid octal number (i.e., contains characters other than 0-7),
+     * the method throws an IllegalArgumentException.
      *
-     * @param args Command line arguments
+     * @param inputOctal The octal number as a string
+     * @return The decimal equivalent of the octal number
+     * @throws IllegalArgumentException if the input is not a valid octal number
      */
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        System.out.print("Octal Input: ");
-        String inputOctal = sc.nextLine();
-        int result = convertOctalToDecimal(inputOctal);
-        if (result != -1) {
-            System.out.println("Result convertOctalToDecimal : " + result);
+    public static int convertOctalToDecimal(String inputOctal) {
+        if (inputOctal == null || inputOctal.isEmpty()) {
+            throw new IllegalArgumentException("Input cannot be null or empty");
         }
-        sc.close();
-    }
 
-    /**
-     * This method converts an octal number to a decimal number.
-     *
-     * @param inputOctal The octal number
-     * @return The decimal number
-     */
-    public static int convertOctalToDecimal(String inputOctal) {
-        try {
-            // Actual conversion of Octal to Decimal:
-            return Integer.parseInt(inputOctal, 8);
-        } catch (NumberFormatException ne) {
-            // Printing a warning message if the input is not a valid octal
-            // number:
-            System.out.println("Invalid Input, Expecting octal number 0-7");
-            return -1;
+        int decimalValue = 0;
+
+        for (int i = 0; i < inputOctal.length(); i++) {
+            char currentChar = inputOctal.charAt(i);
+
+            if (currentChar < '0' || currentChar > '7') {
+                throw new IllegalArgumentException("Incorrect input: Expecting an octal number (digits 0-7)");
+            }
+
+            int currentDigit = currentChar - '0';
+            decimalValue = decimalValue * OCTAL_BASE + currentDigit;
         }
+
+        return decimalValue;
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java b/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java
index 6e17ea14efc8..20f0fa40c626 100644
--- a/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java
@@ -1,14 +1,21 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class OctalToDecimalTest {
 
-    @Test
-    public void testOctalToDecimal() {
-        assertEquals(1465, OctalToDecimal.convertOctalToDecimal("2671"));
-        assertEquals(189, OctalToDecimal.convertOctalToDecimal("275"));
+    @ParameterizedTest
+    @CsvSource({"10, 8", "7, 7", "77, 63", "123, 83", "0, 0", "777, 511", "2671, 1465", "275, 189"})
+    void testConvertOctalToDecimal(String inputOctal, int expectedDecimal) {
+        Assertions.assertEquals(expectedDecimal, OctalToDecimal.convertOctalToDecimal(inputOctal));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"'', Input cannot be null or empty", "'8', Incorrect input: Expecting an octal number (digits 0-7)", "'19', Incorrect input: Expecting an octal number (digits 0-7)"})
+    void testIncorrectInput(String inputOctal, String expectedMessage) {
+        IllegalArgumentException exception = Assertions.assertThrows(IllegalArgumentException.class, () -> OctalToDecimal.convertOctalToDecimal(inputOctal));
+        Assertions.assertEquals(expectedMessage, exception.getMessage());
     }
 }

From 33fd79ad55af74c5aae48906c15838f6ed710a85 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 18 Aug 2024 21:03:28 +0200
Subject: [PATCH 0288/1338] refactor: `OctalToHexadecimal` (#5345)

---
 .../conversions/OctalToHexadecimal.java       | 76 +++++++++----------
 .../conversions/OctalToHexadecimalTest.java   | 23 ++++--
 2 files changed, 52 insertions(+), 47 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java b/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java
index 5cc97fde12aa..bac56dc2e221 100644
--- a/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java
@@ -1,65 +1,61 @@
 package com.thealgorithms.conversions;
 
-import java.util.Scanner;
-
 /**
- * Converts any Octal Number to HexaDecimal
+ * Class for converting an Octal number to its Hexadecimal equivalent.
  *
  * @author Tanmay Joshi
  */
 public final class OctalToHexadecimal {
+    private static final int OCTAL_BASE = 8;
+    private static final int HEX_BASE = 16;
+    private static final String HEX_DIGITS = "0123456789ABCDEF";
+
     private OctalToHexadecimal() {
     }
 
     /**
-     * This method converts a Octal number to a decimal number
+     * Converts an Octal number (as a string) to its Decimal equivalent.
      *
-     * @param s The Octal Number
-     * @return The Decimal number
+     * @param octalNumber The Octal number as a string
+     * @return The Decimal equivalent of the Octal number
+     * @throws IllegalArgumentException if the input contains invalid octal digits
      */
-    public static int octToDec(String s) {
-        int i = 0;
-        for (int j = 0; j < s.length(); j++) {
-            char num = s.charAt(j);
-            num -= '0';
-            i *= 8;
-            i += num;
+    public static int octalToDecimal(String octalNumber) {
+        if (octalNumber == null || octalNumber.isEmpty()) {
+            throw new IllegalArgumentException("Input cannot be null or empty");
         }
-        return i;
+
+        int decimalValue = 0;
+        for (int i = 0; i < octalNumber.length(); i++) {
+            char currentChar = octalNumber.charAt(i);
+            if (currentChar < '0' || currentChar > '7') {
+                throw new IllegalArgumentException("Incorrect octal digit: " + currentChar);
+            }
+            int currentDigit = currentChar - '0';
+            decimalValue = decimalValue * OCTAL_BASE + currentDigit;
+        }
+
+        return decimalValue;
     }
 
     /**
-     * This method converts a Decimal number to a Hexadecimal number
+     * Converts a Decimal number to its Hexadecimal equivalent.
      *
-     * @param d The Decimal Number
-     * @return The Hexadecimal number
+     * @param decimalNumber The Decimal number
+     * @return The Hexadecimal equivalent of the Decimal number
      */
-    public static String decimalToHex(int d) {
-        String digits = "0123456789ABCDEF";
-        if (d <= 0) {
+    public static String decimalToHexadecimal(int decimalNumber) {
+        if (decimalNumber == 0) {
             return "0";
         }
-        String hex = "";
-        while (d > 0) {
-            int digit = d % 16;
-            hex = digits.charAt(digit) + hex;
-            d = d / 16;
-        }
-        return hex;
-    }
 
-    public static void main(String[] args) {
-        Scanner input = new Scanner(System.in);
-        System.out.print("Enter the Octal number: ");
-        // Take octal number as input from user in a string
-        String oct = input.next();
-
-        // Pass the octal number to function and get converted decimal form
-        int decimal = octToDec(oct);
+        StringBuilder hexValue = new StringBuilder();
+        while (decimalNumber > 0) {
+            int digit = decimalNumber % HEX_BASE;
+            hexValue.insert(0, HEX_DIGITS.charAt(digit));
+            decimalNumber /= HEX_BASE;
+        }
 
-        // Pass the decimal number to function and get converted Hex form of the number
-        String hex = decimalToHex(decimal);
-        System.out.println("The Hexadecimal equivalant is: " + hex);
-        input.close();
+        return hexValue.toString();
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java b/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java
index f71732b27d51..6f2ccc24ab2f 100644
--- a/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java
@@ -1,14 +1,23 @@
 package com.thealgorithms.conversions;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class OctalToHexadecimalTest {
 
-    @Test
-    public void testOctalToHexadecimal() {
-        assertEquals("1EA", OctalToHexadecimal.decimalToHex(OctalToHexadecimal.octToDec("752")));
-        assertEquals("15E", OctalToHexadecimal.decimalToHex(OctalToHexadecimal.octToDec("536")));
+    @ParameterizedTest
+    @CsvSource({"0, 0", "7, 7", "10, 8", "17, F", "20, 10", "777, 1FF", "1234, 29C", "752, 1EA", "536, 15E"})
+    void testCorrectInputs(String inputOctal, String expectedHex) {
+        int decimal = OctalToHexadecimal.octalToDecimal(inputOctal);
+        String hex = OctalToHexadecimal.decimalToHexadecimal(decimal);
+        Assertions.assertEquals(expectedHex, hex);
+    }
+
+    @ParameterizedTest
+    @CsvSource({"'', Input cannot be null or empty", "'8', Incorrect octal digit: 8", "'19', Incorrect octal digit: 9"})
+    void testIncorrectInputs(String inputOctal, String expectedMessage) {
+        IllegalArgumentException exception = Assertions.assertThrows(IllegalArgumentException.class, () -> OctalToHexadecimal.octalToDecimal(inputOctal));
+        Assertions.assertEquals(expectedMessage, exception.getMessage());
     }
 }

From 04eae87512e18f5cb909575cc5df6ce2086a4ec5 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 19 Aug 2024 10:15:47 +0200
Subject: [PATCH 0289/1338] refactor: `DynamicArray` (#5346)

---
 .../dynamicarray/DynamicArray.java            | 187 ++++++-------
 .../dynamicarray/DynamicArrayTest.java        | 255 ++++++++++++++++++
 2 files changed, 337 insertions(+), 105 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
index cfec2e3b2c37..a5fa9cbe94e7 100644
--- a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
@@ -10,145 +10,143 @@
 import java.util.stream.StreamSupport;
 
 /**
- * This class implements a dynamic array
+ * This class implements a dynamic array.
  *
  * @param <E> the type that each index of the array will hold
  */
 public class DynamicArray<E> implements Iterable<E> {
 
     private static final int DEFAULT_CAPACITY = 16;
-
-    private int capacity;
     private int size;
+    private int modCount; // Tracks structural modifications for the iterator
     private Object[] elements;
 
     /**
-     * constructor
+     * Constructor with initial capacity.
      *
      * @param capacity the starting length of the desired array
+     * @throws IllegalArgumentException if the specified capacity is negative
      */
     public DynamicArray(final int capacity) {
+        if (capacity < 0) {
+            throw new IllegalArgumentException("Capacity cannot be negative.");
+        }
         this.size = 0;
-        this.capacity = capacity;
-        this.elements = new Object[this.capacity];
+        this.modCount = 0;
+        this.elements = new Object[capacity];
     }
 
     /**
-     * No-args constructor
+     * No-args constructor with default capacity.
      */
     public DynamicArray() {
         this(DEFAULT_CAPACITY);
     }
 
     /**
-     * Adds an element to the array If full, creates a copy array twice the size
-     * of the current one
+     * Adds an element to the array. If full, creates a new array with double the size.
      *
-     * @param element the element of type <E> to be added to the array
+     * @param element the element to be added to the array
      */
     public void add(final E element) {
-        if (this.size == this.elements.length) {
-            this.elements = Arrays.copyOf(this.elements, newCapacity(2 * this.capacity));
-        }
-
-        this.elements[this.size] = element;
-        size++;
+        ensureCapacity(size + 1);
+        elements[size++] = element;
+        modCount++; // Increment modification count
     }
 
     /**
-     * Places element of type <E> at the desired index
+     * Places an element at the desired index, expanding capacity if necessary.
      *
-     * @param index the index for the element to be placed
+     * @param index   the index for the element to be placed
      * @param element the element to be inserted
+     * @throws IndexOutOfBoundsException if n is less than 0 or greater or equal to the number of elements in the array
      */
     public void put(final int index, E element) {
-        this.elements[index] = element;
+        if (index < 0) {
+            throw new IndexOutOfBoundsException("Index cannot be negative.");
+        }
+        ensureCapacity(index + 1);
+        elements[index] = element;
+        if (index >= size) {
+            size = index + 1;
+        }
+        modCount++; // Increment modification count
     }
 
     /**
-     * get method for element at a given index returns null if the index is
-     * empty
+     * Gets the element at a given index.
      *
      * @param index the desired index of the element
-     * @return <E> the element at the specified index
+     * @return the element at the specified index
+     * @throws IndexOutOfBoundsException if n is less than 0 or greater or equal to the number of elements in the array
      */
+    @SuppressWarnings("unchecked")
     public E get(final int index) {
-        return getElement(index);
+        if (index < 0 || index >= size) {
+            throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
+        }
+        return (E) elements[index];
     }
 
     /**
-     * Removes an element from the array
+     * Removes an element from the array.
      *
      * @param index the index of the element to be removed
-     * @return <E> the element removed
+     * @return the element removed
+     * @throws IndexOutOfBoundsException if n is less than 0 or greater or equal to the number of elements in the array
      */
     public E remove(final int index) {
-        final E oldElement = getElement(index);
-        fastRemove(this.elements, index);
-
-        if (this.capacity > DEFAULT_CAPACITY && size * 4 <= this.capacity) {
-            this.elements = Arrays.copyOf(this.elements, newCapacity(this.capacity / 2));
+        if (index < 0 || index >= size) {
+            throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
         }
+        @SuppressWarnings("unchecked") E oldElement = (E) elements[index];
+        fastRemove(index);
+        modCount++; // Increment modification count
         return oldElement;
     }
 
     /**
-     * get method for size field
+     * Gets the size of the array.
      *
-     * @return int size
+     * @return the size
      */
     public int getSize() {
-        return this.size;
+        return size;
     }
 
     /**
-     * isEmpty helper method
+     * Checks if the array is empty.
      *
-     * @return boolean true if the array contains no elements, false otherwise
+     * @return true if the array contains no elements, false otherwise
      */
     public boolean isEmpty() {
-        return this.size == 0;
+        return size == 0;
     }
 
     public Stream<E> stream() {
         return StreamSupport.stream(spliterator(), false);
     }
 
-    private void fastRemove(final Object[] elements, final int index) {
-        final int newSize = this.size - 1;
-
-        if (newSize > index) {
-            System.arraycopy(elements, index + 1, elements, index, newSize - index);
+    private void ensureCapacity(int minCapacity) {
+        if (minCapacity > elements.length) {
+            int newCapacity = Math.max(elements.length * 2, minCapacity);
+            elements = Arrays.copyOf(elements, newCapacity);
         }
-
-        this.size = newSize;
-        this.elements[this.size] = null;
     }
 
-    private E getElement(final int index) {
-        return (E) this.elements[index];
-    }
-
-    private int newCapacity(int capacity) {
-        this.capacity = capacity;
-        return this.capacity;
+    private void fastRemove(int index) {
+        int numMoved = size - index - 1;
+        if (numMoved > 0) {
+            System.arraycopy(elements, index + 1, elements, index, numMoved);
+        }
+        elements[--size] = null; // Clear to let GC do its work
     }
 
-    /**
-     * returns a String representation of this object
-     *
-     * @return String a String representing the array
-     */
     @Override
     public String toString() {
-        return Arrays.toString(Arrays.stream(this.elements).filter(Objects::nonNull).toArray());
+        return Arrays.toString(Arrays.copyOf(elements, size));
     }
 
-    /**
-     * Creates and returns a new Dynamic Array Iterator
-     *
-     * @return Iterator a Dynamic Array Iterator
-     */
     @Override
     public Iterator<E> iterator() {
         return new DynamicArrayIterator();
@@ -157,71 +155,50 @@ public Iterator<E> iterator() {
     private final class DynamicArrayIterator implements Iterator<E> {
 
         private int cursor;
+        private int expectedModCount;
+
+        DynamicArrayIterator() {
+            this.expectedModCount = modCount;
+        }
 
         @Override
         public boolean hasNext() {
-            return this.cursor != size;
+            checkForComodification();
+            return cursor < size;
         }
 
         @Override
+        @SuppressWarnings("unchecked")
         public E next() {
-            if (this.cursor > DynamicArray.this.size) {
+            checkForComodification();
+            if (cursor >= size) {
                 throw new NoSuchElementException();
             }
-
-            if (this.cursor > DynamicArray.this.elements.length) {
-                throw new ConcurrentModificationException();
-            }
-
-            final E element = DynamicArray.this.getElement(this.cursor);
-            this.cursor++;
-
-            return element;
+            return (E) elements[cursor++];
         }
 
         @Override
         public void remove() {
-            if (this.cursor < 0) {
+            if (cursor <= 0) {
                 throw new IllegalStateException();
             }
+            checkForComodification();
+            DynamicArray.this.remove(--cursor);
+            expectedModCount = ++modCount;
+        }
 
-            DynamicArray.this.remove(this.cursor);
-            this.cursor--;
+        private void checkForComodification() {
+            if (modCount != expectedModCount) {
+                throw new ConcurrentModificationException();
+            }
         }
 
         @Override
         public void forEachRemaining(Consumer<? super E> action) {
             Objects.requireNonNull(action);
-
-            for (int i = 0; i < DynamicArray.this.size; i++) {
-                action.accept(DynamicArray.this.getElement(i));
+            while (hasNext()) {
+                action.accept(next());
             }
         }
     }
-
-    /**
-     * This class is the driver for the DynamicArray<E> class it tests a variety
-     * of methods and prints the output
-     */
-    public static void main(String[] args) {
-        DynamicArray<String> names = new DynamicArray<>();
-        names.add("Peubes");
-        names.add("Marley");
-
-        for (String name : names) {
-            System.out.println(name);
-        }
-
-        names.stream().forEach(System.out::println);
-
-        System.out.println(names);
-
-        System.out.println(names.getSize());
-
-        names.remove(0);
-
-        for (String name : names) {
-            System.out.println(name);
-        }
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java b/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java
new file mode 100644
index 000000000000..8e067086689b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java
@@ -0,0 +1,255 @@
+package com.thealgorithms.datastructures.dynamicarray;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ConcurrentModificationException;
+import java.util.Iterator;
+import java.util.stream.Collectors;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class DynamicArrayTest {
+
+    private DynamicArray<String> array;
+
+    @BeforeEach
+    public void setUp() {
+        array = new DynamicArray<>();
+    }
+
+    @Test
+    public void testGetElement() {
+        array.add("Alice");
+        array.add("Bob");
+        assertEquals("Bob", array.get(1));
+    }
+
+    @Test
+    public void testGetInvalidIndex() {
+        assertThrows(IndexOutOfBoundsException.class, () -> array.get(-1));
+        assertThrows(IndexOutOfBoundsException.class, () -> array.get(10));
+    }
+
+    @Test
+    public void testAddElement() {
+        array.add("Alice");
+        array.add("Bob");
+        assertEquals(2, array.getSize());
+        assertEquals("Alice", array.get(0));
+        assertEquals("Bob", array.get(1));
+    }
+
+    @Test
+    public void testAddAndGet() {
+        array.add("Alice");
+        array.add("Bob");
+
+        assertEquals("Alice", array.get(0));
+        assertEquals("Bob", array.get(1));
+        assertThrows(IndexOutOfBoundsException.class, () -> array.get(2));
+    }
+
+    @Test
+    public void testAddBeyondCapacity() {
+        for (int i = 0; i < 20; i++) {
+            array.add("Element " + i);
+        }
+        assertEquals(20, array.getSize());
+        assertEquals("Element 19", array.get(19));
+    }
+
+    @Test
+    public void testPutElement() {
+        array.put(5, "Placeholder");
+        assertEquals(6, array.getSize());
+        assertEquals("Placeholder", array.get(5));
+    }
+
+    @Test
+    public void testPutElementBeyondCapacity() {
+        array.put(20, "FarAway");
+        assertEquals(21, array.getSize());
+        assertEquals("FarAway", array.get(20));
+    }
+
+    @Test
+    public void testPutAndDynamicCapacity() {
+        array.put(0, "Alice");
+        array.put(2, "Bob"); // Tests capacity expansion
+
+        assertEquals("Alice", array.get(0));
+        assertEquals("Bob", array.get(2));
+        assertEquals(3, array.getSize()); // Size should be 3 due to index 2
+    }
+
+    @Test
+    public void testRemoveElement() {
+        array.add("Alice");
+        array.add("Bob");
+        String removed = array.remove(0);
+        assertEquals("Alice", removed);
+        assertEquals(1, array.getSize());
+        assertEquals("Bob", array.get(0));
+    }
+
+    @Test
+    public void testRemoveInvalidIndex() {
+        assertThrows(IndexOutOfBoundsException.class, () -> array.remove(-1));
+        assertThrows(IndexOutOfBoundsException.class, () -> array.remove(10));
+    }
+
+    @Test
+    public void testRemoveComplex() {
+        array.add("Alice");
+        array.add("Bob");
+        array.add("Charlie");
+
+        assertEquals("Bob", array.remove(1));
+        assertEquals("Alice", array.get(0));
+        assertEquals("Charlie", array.get(1));
+        assertThrows(IndexOutOfBoundsException.class, () -> array.remove(2));
+    }
+
+    @Test
+    public void testRemoveEdgeCases() {
+        array.add("Alice");
+        array.add("Bob");
+
+        assertEquals("Alice", array.remove(0));
+        assertEquals(1, array.getSize());
+        assertEquals("Bob", array.get(0));
+
+        assertEquals("Bob", array.remove(0));
+        assertTrue(array.isEmpty());
+        assertThrows(IndexOutOfBoundsException.class, () -> array.get(0));
+    }
+
+    @Test
+    public void testIsEmpty() {
+        assertTrue(array.isEmpty());
+
+        array.add("Alice");
+        assertFalse(array.isEmpty());
+
+        array.remove(0);
+        assertTrue(array.isEmpty());
+    }
+
+    @Test
+    public void testSize() {
+        DynamicArray<String> array = new DynamicArray<>();
+        assertEquals(0, array.getSize());
+
+        array.add("Alice");
+        array.add("Bob");
+        assertEquals(2, array.getSize());
+
+        array.remove(0);
+        assertEquals(1, array.getSize());
+    }
+
+    @Test
+    public void testToString() {
+        array.add("Alice");
+        array.add("Bob");
+
+        assertEquals("[Alice, Bob]", array.toString());
+    }
+
+    @Test
+    public void testIterator() {
+        array.add("Alice");
+        array.add("Bob");
+
+        String result = array.stream().collect(Collectors.joining(", "));
+        assertEquals("Alice, Bob", result);
+    }
+
+    @Test
+    public void testStreamAsString() {
+        array.add("Alice");
+        array.add("Bob");
+
+        String result = array.stream().collect(Collectors.joining(", "));
+        assertEquals("Alice, Bob", result);
+    }
+
+    @Test
+    public void testStream() {
+        array.add("Alice");
+        array.add("Bob");
+        long count = array.stream().count();
+        assertEquals(2, count);
+    }
+
+    @Test
+    public void testAddToFullCapacity() {
+        DynamicArray<String> array = new DynamicArray<>(2);
+        array.add("Alice");
+        array.add("Bob");
+        array.add("Charlie"); // Triggers capacity expansion
+
+        assertEquals(3, array.getSize());
+        assertEquals("Charlie", array.get(2));
+    }
+
+    @Test
+    public void testPutWithNegativeIndex() {
+        assertThrows(IndexOutOfBoundsException.class, () -> array.put(-1, "Alice"));
+    }
+
+    @Test
+    public void testGetWithNegativeIndex() {
+        assertThrows(IndexOutOfBoundsException.class, () -> array.get(-1));
+    }
+
+    @Test
+    public void testIteratorConcurrentModification() {
+        array.add("Alice");
+        array.add("Bob");
+
+        Iterator<String> iterator = array.iterator();
+        array.add("Charlie"); // Modify during iteration
+
+        assertThrows(ConcurrentModificationException.class, iterator::next);
+    }
+
+    @Test
+    public void testIteratorRemove() {
+        array.add("Alice");
+        array.add("Bob");
+
+        Iterator<String> iterator = array.iterator();
+        assertEquals("Alice", iterator.next());
+        iterator.remove();
+        assertEquals(1, array.getSize());
+        assertEquals("Bob", array.get(0));
+    }
+
+    @Test
+    public void testRemoveBeyondCapacity() {
+        DynamicArray<String> array = new DynamicArray<>(2);
+        array.add("Alice");
+        array.add("Bob");
+        array.add("Charlie");
+
+        array.remove(1);
+        assertEquals(2, array.getSize());
+        assertEquals("Alice", array.get(0));
+        assertEquals("Charlie", array.get(1));
+    }
+
+    @Test
+    public void testCapacityDoubling() {
+        DynamicArray<String> array = new DynamicArray<>(1);
+        array.add("Alice");
+        array.add("Bob");
+        array.add("Charlie"); // Ensure capacity expansion is working
+
+        assertEquals(3, array.getSize());
+        assertEquals("Charlie", array.get(2));
+    }
+}

From 8712a7f4059f307b33b28e5e45aba13d440f1415 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 19 Aug 2024 23:03:19 +0200
Subject: [PATCH 0290/1338] refactor: `Queue` (#5348)

---
 .../datastructures/queues/Queue.java          | 153 +++++++++++++++
 .../datastructures/queues/Queues.java         | 184 ------------------
 .../datastructures/queues/QueueTest.java      | 127 ++++++++++++
 3 files changed, 280 insertions(+), 184 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/queues/Queue.java
 delete mode 100644 src/main/java/com/thealgorithms/datastructures/queues/Queues.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/Queue.java b/src/main/java/com/thealgorithms/datastructures/queues/Queue.java
new file mode 100644
index 000000000000..046b79a020ed
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/queues/Queue.java
@@ -0,0 +1,153 @@
+package com.thealgorithms.datastructures.queues;
+
+/**
+ * This class implements a Queue data structure using an array.
+ * A queue is a first-in-first-out (FIFO) data structure where elements are
+ * added to the rear and removed from the front.
+ *
+ * Note: This implementation is not thread-safe.
+ */
+public final class Queue<T> {
+
+    private static final int DEFAULT_CAPACITY = 10;
+
+    private final int maxSize;
+    private final Object[] queueArray;
+    private int front;
+    private int rear;
+    private int nItems;
+
+    /**
+     * Initializes a queue with a default capacity.
+     */
+    public Queue() {
+        this(DEFAULT_CAPACITY);
+    }
+
+    /**
+     * Constructor to initialize a queue with a specified capacity.
+     *
+     * @param capacity The initial size of the queue.
+     * @throws IllegalArgumentException if the capacity is less than or equal to zero.
+     */
+    public Queue(int capacity) {
+        if (capacity <= 0) {
+            throw new IllegalArgumentException("Queue capacity must be greater than 0");
+        }
+        this.maxSize = capacity;
+        this.queueArray = new Object[capacity];
+        this.front = 0;
+        this.rear = -1;
+        this.nItems = 0;
+    }
+
+    /**
+     * Inserts an element at the rear of the queue.
+     *
+     * @param element Element to be added.
+     * @return True if the element was added successfully, false if the queue is full.
+     */
+    public boolean insert(T element) {
+        if (isFull()) {
+            return false;
+        }
+        rear = (rear + 1) % maxSize;
+        queueArray[rear] = element;
+        nItems++;
+        return true;
+    }
+
+    /**
+     * Removes and returns the element from the front of the queue.
+     *
+     * @return The element removed from the front of the queue.
+     * @throws IllegalStateException if the queue is empty.
+     */
+    @SuppressWarnings("unchecked")
+    public T remove() {
+        if (isEmpty()) {
+            throw new IllegalStateException("Queue is empty, cannot remove element");
+        }
+        T removedElement = (T) queueArray[front];
+        queueArray[front] = null; // Optional: Clear the reference for garbage collection
+        front = (front + 1) % maxSize;
+        nItems--;
+        return removedElement;
+    }
+
+    /**
+     * Checks the element at the front of the queue without removing it.
+     *
+     * @return Element at the front of the queue.
+     * @throws IllegalStateException if the queue is empty.
+     */
+    @SuppressWarnings("unchecked")
+    public T peekFront() {
+        if (isEmpty()) {
+            throw new IllegalStateException("Queue is empty, cannot peek front");
+        }
+        return (T) queueArray[front];
+    }
+
+    /**
+     * Checks the element at the rear of the queue without removing it.
+     *
+     * @return Element at the rear of the queue.
+     * @throws IllegalStateException if the queue is empty.
+     */
+    @SuppressWarnings("unchecked")
+    public T peekRear() {
+        if (isEmpty()) {
+            throw new IllegalStateException("Queue is empty, cannot peek rear");
+        }
+        return (T) queueArray[rear];
+    }
+
+    /**
+     * Returns true if the queue is empty.
+     *
+     * @return True if the queue is empty.
+     */
+    public boolean isEmpty() {
+        return nItems == 0;
+    }
+
+    /**
+     * Returns true if the queue is full.
+     *
+     * @return True if the queue is full.
+     */
+    public boolean isFull() {
+        return nItems == maxSize;
+    }
+
+    /**
+     * Returns the number of elements currently in the queue.
+     *
+     * @return Number of elements in the queue.
+     */
+    public int getSize() {
+        return nItems;
+    }
+
+    /**
+     * Returns a string representation of the queue.
+     *
+     * @return String representation of the queue.
+     */
+    @Override
+    public String toString() {
+        if (isEmpty()) {
+            return "[]";
+        }
+        StringBuilder sb = new StringBuilder();
+        sb.append("[");
+        for (int i = 0; i < nItems; i++) {
+            int index = (front + i) % maxSize;
+            sb.append(queueArray[index]).append(", ");
+        }
+        sb.setLength(sb.length() - 2); // Remove the last comma and space
+        sb.append("]");
+        return sb.toString();
+    }
+}
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/Queues.java b/src/main/java/com/thealgorithms/datastructures/queues/Queues.java
deleted file mode 100644
index 2f364b7cbb6b..000000000000
--- a/src/main/java/com/thealgorithms/datastructures/queues/Queues.java
+++ /dev/null
@@ -1,184 +0,0 @@
-package com.thealgorithms.datastructures.queues;
-
-/**
- * This implements Queues by using the class Queue.
- *
- * A queue data structure functions the same as a real world queue. The elements
- * that are added first are the first to be removed. New elements are added to
- * the back/rear of the queue.
- */
-class Queue {
-
-    /**
-     * Default initial capacity.
-     */
-    private static final int DEFAULT_CAPACITY = 10;
-
-    /**
-     * Max size of the queue
-     */
-    private int maxSize;
-    /**
-     * The array representing the queue
-     */
-    private int[] queueArray;
-    /**
-     * Front of the queue
-     */
-    private int front;
-    /**
-     * Rear of the queue
-     */
-    private int rear;
-    /**
-     * How many items are in the queue
-     */
-    private int nItems;
-
-    /**
-     * init with DEFAULT_CAPACITY
-     */
-    Queue() {
-        this(DEFAULT_CAPACITY);
-    }
-
-    /**
-     * Constructor
-     *
-     * @param size Size of the new queue
-     */
-    Queue(int size) {
-        maxSize = size;
-        queueArray = new int[size];
-        front = 0;
-        rear = -1;
-        nItems = 0;
-    }
-
-    /**
-     * Inserts an element at the rear of the queue
-     *
-     * @param x element to be added
-     * @return True if the element was added successfully
-     */
-    public boolean insert(int x) {
-        if (isFull()) {
-            return false;
-        }
-        // If the back of the queue is the end of the array wrap around to the front
-        rear = (rear + 1) % maxSize;
-        queueArray[rear] = x;
-        nItems++;
-        return true;
-    }
-
-    /**
-     * Remove an element from the front of the queue
-     *
-     * @return the new front of the queue
-     */
-    public int remove() {
-        if (isEmpty()) {
-            return -1;
-        }
-        int temp = queueArray[front];
-        front = (front + 1) % maxSize;
-        nItems--;
-        return temp;
-    }
-
-    /**
-     * Checks what's at the front of the queue
-     *
-     * @return element at the front of the queue
-     */
-    public int peekFront() {
-        return queueArray[front];
-    }
-
-    /**
-     * Checks what's at the rear of the queue
-     *
-     * @return element at the rear of the queue
-     */
-    public int peekRear() {
-        return queueArray[rear];
-    }
-
-    /**
-     * Returns true if the queue is empty
-     *
-     * @return true if the queue is empty
-     */
-    public boolean isEmpty() {
-        return nItems == 0;
-    }
-
-    /**
-     * Returns true if the queue is full
-     *
-     * @return true if the queue is full
-     */
-    public boolean isFull() {
-        return nItems == maxSize;
-    }
-
-    /**
-     * Returns the number of elements in the queue
-     *
-     * @return number of elements in the queue
-     */
-    public int getSize() {
-        return nItems;
-    }
-
-    @Override
-    public String toString() {
-        StringBuilder sb = new StringBuilder();
-        sb.append("[");
-        for (int i = front;; i = ++i % maxSize) {
-            sb.append(queueArray[i]).append(", ");
-            if (i == rear) {
-                break;
-            }
-        }
-        sb.replace(sb.length() - 2, sb.length(), "]");
-        return sb.toString();
-    }
-}
-
-/**
- * This class is the example for the Queue class
- *
- * @author Unknown
- */
-public final class Queues {
-    private Queues() {
-    }
-
-    /**
-     * Main method
-     *
-     * @param args Command line arguments
-     */
-    public static void main(String[] args) {
-        Queue myQueue = new Queue(4);
-        myQueue.insert(10);
-        myQueue.insert(2);
-        myQueue.insert(5);
-        myQueue.insert(3);
-        // [10(front), 2, 5, 3(rear)]
-
-        System.out.println(myQueue.isFull()); // Will print true
-
-        myQueue.remove(); // Will make 2 the new front, making 10 no longer part of the queue
-        // [10, 2(front), 5, 3(rear)]
-
-        myQueue.insert(7); // Insert 7 at the rear which will get 0 index because of wrap around
-        // [7(rear), 2(front), 5, 3]
-
-        System.out.println(myQueue.peekFront()); // Will print 2
-        System.out.println(myQueue.peekRear()); // Will print 7
-        System.out.println(myQueue); // Will print [2, 5, 3, 7]
-    }
-}
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java b/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java
new file mode 100644
index 000000000000..9a4f50d5e216
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java
@@ -0,0 +1,127 @@
+package com.thealgorithms.datastructures.queues;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class QueueTest {
+
+    private static final int INITIAL_CAPACITY = 3;
+    private Queue<Integer> queue;
+
+    @BeforeEach
+    void setUp() {
+        queue = new Queue<>(INITIAL_CAPACITY);
+    }
+
+    @Test
+    void testQueueInsertion() {
+        Assertions.assertTrue(queue.insert(1));
+        Assertions.assertTrue(queue.insert(2));
+        Assertions.assertTrue(queue.insert(3));
+        Assertions.assertFalse(queue.insert(4)); // Queue is full
+
+        Assertions.assertEquals(1, queue.peekFront());
+        Assertions.assertEquals(3, queue.peekRear());
+        Assertions.assertEquals(3, queue.getSize());
+    }
+
+    @Test
+    void testQueueRemoval() {
+        queue.insert(1);
+        queue.insert(2);
+        queue.insert(3);
+
+        Assertions.assertEquals(1, queue.remove());
+        Assertions.assertEquals(2, queue.peekFront());
+        Assertions.assertEquals(2, queue.getSize());
+
+        Assertions.assertEquals(2, queue.remove());
+        Assertions.assertEquals(3, queue.peekFront());
+        Assertions.assertEquals(1, queue.getSize());
+
+        Assertions.assertEquals(3, queue.remove());
+        Assertions.assertTrue(queue.isEmpty());
+
+        Assertions.assertThrows(IllegalStateException.class, queue::remove); // Queue is empty
+    }
+
+    @Test
+    void testPeekFrontAndRear() {
+        queue.insert(1);
+        queue.insert(2);
+
+        Assertions.assertEquals(1, queue.peekFront());
+        Assertions.assertEquals(2, queue.peekRear());
+
+        queue.insert(3);
+        Assertions.assertEquals(1, queue.peekFront());
+        Assertions.assertEquals(3, queue.peekRear());
+    }
+
+    @Test
+    void testQueueIsEmptyAndIsFull() {
+        Assertions.assertTrue(queue.isEmpty());
+        Assertions.assertFalse(queue.isFull());
+
+        queue.insert(1);
+        queue.insert(2);
+        queue.insert(3);
+
+        Assertions.assertFalse(queue.isEmpty());
+        Assertions.assertTrue(queue.isFull());
+
+        queue.remove();
+        Assertions.assertFalse(queue.isFull());
+        Assertions.assertFalse(queue.isEmpty());
+    }
+
+    @Test
+    void testQueueSize() {
+        Assertions.assertEquals(0, queue.getSize());
+        queue.insert(1);
+        Assertions.assertEquals(1, queue.getSize());
+        queue.insert(2);
+        Assertions.assertEquals(2, queue.getSize());
+        queue.insert(3);
+        Assertions.assertEquals(3, queue.getSize());
+        queue.remove();
+        Assertions.assertEquals(2, queue.getSize());
+    }
+
+    @Test
+    void testQueueToString() {
+        Assertions.assertEquals("[]", queue.toString());
+
+        queue.insert(1);
+        queue.insert(2);
+        Assertions.assertEquals("[1, 2]", queue.toString());
+
+        queue.insert(3);
+        Assertions.assertEquals("[1, 2, 3]", queue.toString());
+
+        queue.remove();
+        Assertions.assertEquals("[2, 3]", queue.toString());
+
+        queue.remove();
+        queue.remove();
+        Assertions.assertEquals("[]", queue.toString());
+    }
+
+    @Test
+    void testQueueThrowsExceptionOnEmptyPeek() {
+        Assertions.assertThrows(IllegalStateException.class, queue::peekFront);
+        Assertions.assertThrows(IllegalStateException.class, queue::peekRear);
+    }
+
+    @Test
+    void testQueueThrowsExceptionOnRemoveFromEmptyQueue() {
+        Assertions.assertThrows(IllegalStateException.class, queue::remove);
+    }
+
+    @Test
+    void testQueueCapacityException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new Queue<>(0));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new Queue<>(-5));
+    }
+}

From 86052207219363a4982f9864e9ed3e9f03b160b3 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 20 Aug 2024 00:19:40 +0200
Subject: [PATCH 0291/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-surefire-plugin from 3.3.1 to 3.4.0 (#5350)

Chore(deps): bump org.apache.maven.plugins:maven-surefire-plugin

Bumps [org.apache.maven.plugins:maven-surefire-plugin](https://github.com/apache/maven-surefire) from 3.3.1 to 3.4.0.
- [Release notes](https://github.com/apache/maven-surefire/releases)
- [Commits](https://github.com/apache/maven-surefire/compare/surefire-3.3.1...surefire-3.4.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-surefire-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 6387ced0c224..a46e469c40e3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -63,7 +63,7 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.3.1</version>
+                <version>3.4.0</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>

From f5c0314111f5973748862e21d6e7ccbb9e53a3ee Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 20 Aug 2024 12:10:18 +0200
Subject: [PATCH 0292/1338] refactor: `StackArray` (#5349)

---
 .../datastructures/stacks/Stack.java          |  51 ++++++
 .../datastructures/stacks/StackArray.java     | 164 ++++--------------
 .../datastructures/stacks/StackArrayTest.java | 121 +++++++++++++
 3 files changed, 209 insertions(+), 127 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/stacks/Stack.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/Stack.java b/src/main/java/com/thealgorithms/datastructures/stacks/Stack.java
new file mode 100644
index 000000000000..87058bd9750f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/Stack.java
@@ -0,0 +1,51 @@
+package com.thealgorithms.datastructures.stacks;
+
+/**
+ * A generic interface for Stack data structures.
+ *
+ * @param <T> the type of elements in this stack
+ */
+public interface Stack<T> {
+
+    /**
+     * Adds an element to the top of the stack.
+     *
+     * @param value The element to add.
+     */
+    void push(T value);
+
+    /**
+     * Removes the element at the top of this stack and returns it.
+     *
+     * @return The element popped from the stack.
+     * @throws IllegalStateException if the stack is empty.
+     */
+    T pop();
+
+    /**
+     * Returns the element at the top of this stack without removing it.
+     *
+     * @return The element at the top of this stack.
+     * @throws IllegalStateException if the stack is empty.
+     */
+    T peek();
+
+    /**
+     * Tests if this stack is empty.
+     *
+     * @return {@code true} if this stack is empty; {@code false} otherwise.
+     */
+    boolean isEmpty();
+
+    /**
+     * Returns the size of this stack.
+     *
+     * @return The number of elements in this stack.
+     */
+    int size();
+
+    /**
+     * Removes all elements from this stack.
+     */
+    void makeEmpty();
+}
diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java b/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java
index cb2cb25e9e0c..f98db7cc1550 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java
@@ -3,170 +3,80 @@
 /**
  * This class implements a Stack using a regular array.
  *
- * <p>
- * A stack is exactly what it sounds like. An element gets added to the top of
- * the stack and only the element on the top may be removed. This is an example
- * of an array implementation of a Stack. So an element can only be
- * added/removed from the end of the array. In theory stack have no fixed size,
- * but with an array implementation it does.
+ * @param <T> the type of elements in this stack
  */
-public class StackArray {
+public class StackArray<T> implements Stack<T> {
 
-    /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        // Declare a stack of maximum size 4
-        StackArray myStackArray = new StackArray(4);
-
-        assert myStackArray.isEmpty();
-        assert !myStackArray.isFull();
-
-        // Populate the stack
-        myStackArray.push(5);
-        myStackArray.push(8);
-        myStackArray.push(2);
-        myStackArray.push(9);
-
-        assert !myStackArray.isEmpty();
-        assert myStackArray.isFull();
-        assert myStackArray.peek() == 9;
-        assert myStackArray.pop() == 9;
-        assert myStackArray.peek() == 2;
-        assert myStackArray.size() == 3;
-    }
-
-    /**
-     * Default initial capacity.
-     */
     private static final int DEFAULT_CAPACITY = 10;
 
-    /**
-     * The max size of the Stack
-     */
     private int maxSize;
-
-    /**
-     * The array representation of the Stack
-     */
-    private int[] stackArray;
-
-    /**
-     * The top of the stack
-     */
+    private T[] stackArray;
     private int top;
 
-    /**
-     * init Stack with DEFAULT_CAPACITY
-     */
+    @SuppressWarnings("unchecked")
     public StackArray() {
         this(DEFAULT_CAPACITY);
     }
 
-    /**
-     * Constructor
-     *
-     * @param size Size of the Stack
-     */
+    @SuppressWarnings("unchecked")
     public StackArray(int size) {
-        maxSize = size;
-        stackArray = new int[maxSize];
-        top = -1;
+        if (size <= 0) {
+            throw new IllegalArgumentException("Stack size must be greater than 0");
+        }
+        this.maxSize = size;
+        this.stackArray = (T[]) new Object[size];
+        this.top = -1;
     }
 
-    /**
-     * Adds an element to the top of the stack
-     *
-     * @param value The element added
-     */
-    public void push(int value) {
-        if (!isFull()) { // Checks for a full stack
-            top++;
-            stackArray[top] = value;
-        } else {
+    @Override
+    public void push(T value) {
+        if (isFull()) {
             resize(maxSize * 2);
-            push(value); // don't forget push after resizing
         }
+        stackArray[++top] = value;
     }
 
-    /**
-     * Removes the top element of the stack and returns the value you've removed
-     *
-     * @return value popped off the Stack
-     */
-    public int pop() {
-        if (!isEmpty()) { // Checks for an empty stack
-            return stackArray[top--];
+    @Override
+    public T pop() {
+        if (isEmpty()) {
+            throw new IllegalStateException("Stack is empty, cannot pop element");
         }
-
-        if (top < maxSize / 4) {
+        T value = stackArray[top--];
+        if (top + 1 < maxSize / 4 && maxSize > DEFAULT_CAPACITY) {
             resize(maxSize / 2);
-            return pop(); // don't forget pop after resizing
-        } else {
-            System.out.println("The stack is already empty");
-            return -1;
         }
+        return value;
     }
 
-    /**
-     * Returns the element at the top of the stack
-     *
-     * @return element at the top of the stack
-     */
-    public int peek() {
-        if (!isEmpty()) { // Checks for an empty stack
-            return stackArray[top];
-        } else {
-            System.out.println("The stack is empty, cant peek");
-            return -1;
+    @Override
+    public T peek() {
+        if (isEmpty()) {
+            throw new IllegalStateException("Stack is empty, cannot peek element");
         }
+        return stackArray[top];
     }
 
     private void resize(int newSize) {
-        int[] transferArray = new int[newSize];
-
-        for (int i = 0; i < stackArray.length; i++) {
-            transferArray[i] = stackArray[i];
-        }
-        // This reference change might be nice in here
-        stackArray = transferArray;
+        @SuppressWarnings("unchecked") T[] newArray = (T[]) new Object[newSize];
+        System.arraycopy(stackArray, 0, newArray, 0, top + 1);
+        stackArray = newArray;
         maxSize = newSize;
     }
 
-    /**
-     * Returns true if the stack is empty
-     *
-     * @return true if the stack is empty
-     */
-    public boolean isEmpty() {
-        return (top == -1);
+    public boolean isFull() {
+        return top + 1 == maxSize;
     }
 
-    /**
-     * Returns true if the stack is full
-     *
-     * @return true if the stack is full
-     */
-    public boolean isFull() {
-        return (top + 1 == maxSize);
+    @Override
+    public boolean isEmpty() {
+        return top == -1;
     }
 
-    /**
-     * Deletes everything in the Stack
-     *
-     * <p>
-     * Doesn't delete elements in the array but if you call push method after
-     * calling makeEmpty it will overwrite previous values
-     */
-    public void makeEmpty() { // Doesn't delete elements in the array but if you call
+    @Override public void makeEmpty() { // Doesn't delete elements in the array but if you call
         top = -1; // push method after calling makeEmpty it will overwrite previous values
     }
 
-    /**
-     * Return size of stack
-     *
-     * @return size of stack
-     */
+    @Override
     public int size() {
         return top + 1;
     }
diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java
new file mode 100644
index 000000000000..3cda2f54708e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java
@@ -0,0 +1,121 @@
+package com.thealgorithms.datastructures.stacks;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class StackArrayTest {
+
+    private Stack<Integer> stack;
+
+    @BeforeEach
+    void setUp() {
+        stack = new StackArray<>(5); // Initialize a stack with capacity of 5
+    }
+
+    @Test
+    void testPushAndPop() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+        stack.push(4);
+        stack.push(5);
+
+        Assertions.assertEquals(5, stack.pop()); // Stack follows LIFO, so 5 should be popped first
+        Assertions.assertEquals(4, stack.pop()); // Next, 4 should be popped
+        Assertions.assertEquals(3, stack.pop()); // Followed by 3
+        Assertions.assertEquals(2, stack.pop()); // Then 2
+        Assertions.assertEquals(1, stack.pop()); // Finally 1
+    }
+
+    @Test
+    void testPeek() {
+        stack.push(10);
+        stack.push(20);
+        stack.push(30);
+
+        Assertions.assertEquals(30, stack.peek()); // Peek should return 30, the top of the stack
+        Assertions.assertEquals(3, stack.size()); // Size should remain 3 after peek
+
+        stack.pop();
+        Assertions.assertEquals(20, stack.peek()); // After popping, peek should return 20
+    }
+
+    @Test
+    void testIsEmpty() {
+        Assertions.assertTrue(stack.isEmpty()); // Initially, the stack should be empty
+        stack.push(42);
+        Assertions.assertFalse(stack.isEmpty()); // After pushing an element, the stack should not be empty
+        stack.pop();
+        Assertions.assertTrue(stack.isEmpty()); // After popping the only element, the stack should be empty again
+    }
+
+    @Test
+    void testResizeOnPush() {
+        StackArray<Integer> smallStack = new StackArray<>(2); // Start with a small stack size
+        smallStack.push(1);
+        smallStack.push(2);
+        Assertions.assertTrue(smallStack.isFull()); // Initially, the stack should be full
+
+        smallStack.push(3); // This push should trigger a resize
+        Assertions.assertFalse(smallStack.isFull()); // The stack should no longer be full after resize
+        Assertions.assertEquals(3, smallStack.size()); // Size should be 3 after pushing 3 elements
+
+        Assertions.assertEquals(3, smallStack.pop()); // LIFO behavior check
+        Assertions.assertEquals(2, smallStack.pop());
+        Assertions.assertEquals(1, smallStack.pop());
+    }
+
+    @Test
+    void testResizeOnPop() {
+        StackArray<Integer> stack = new StackArray<>(4);
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+        stack.push(4);
+
+        stack.pop(); // Removing elements should trigger a resize when less than 1/4 of the stack is used
+        stack.pop();
+        stack.pop();
+        Assertions.assertEquals(1, stack.size()); // After popping, only one element should remain
+
+        stack.pop();
+        Assertions.assertTrue(stack.isEmpty()); // The stack should be empty now
+    }
+
+    @Test
+    void testMakeEmpty() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+        stack.makeEmpty();
+
+        Assertions.assertTrue(stack.isEmpty()); // The stack should be empty after calling makeEmpty
+        Assertions.assertThrows(IllegalStateException.class, stack::pop); // Popping from empty stack should throw exception
+    }
+
+    @Test
+    void testPopEmptyStackThrowsException() {
+        Assertions.assertThrows(IllegalStateException.class, stack::pop); // Popping from an empty stack should throw an exception
+    }
+
+    @Test
+    void testPeekEmptyStackThrowsException() {
+        Assertions.assertThrows(IllegalStateException.class, stack::peek); // Peeking into an empty stack should throw an exception
+    }
+
+    @Test
+    void testConstructorWithInvalidSizeThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new StackArray<>(0)); // Size 0 is invalid
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new StackArray<>(-5)); // Negative size is invalid
+    }
+
+    @Test
+    void testDefaultConstructor() {
+        StackArray<Integer> defaultStack = new StackArray<>(); // Using default constructor
+        Assertions.assertEquals(0, defaultStack.size()); // Initially, size should be 0
+
+        defaultStack.push(1);
+        Assertions.assertEquals(1, defaultStack.size()); // After pushing, size should be 1
+    }
+}

From e756a7d2d50287b74b1a88cfa578e457f709821f Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 21 Aug 2024 12:26:21 +0200
Subject: [PATCH 0293/1338] refactor: `CircularQueue` (#5354)

---
 .../datastructures/queues/CircularQueue.java  | 120 +++++++++---------
 .../queues/CircularQueueTest.java             | 106 ++++++++++++++++
 2 files changed, 163 insertions(+), 63 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
index 48d9ffe9a42a..c67817a6f2d4 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
@@ -2,106 +2,100 @@
 
 // This program implements the concept of CircularQueue in Java
 // Link to the concept: (https://en.wikipedia.org/wiki/Circular_buffer)
-public class CircularQueue {
-
-    int[] arr;
-    int topOfQueue;
-    int beginningOfQueue;
-    int size;
+public class CircularQueue<T> {
+    private T[] array;
+    private int topOfQueue;
+    private int beginningOfQueue;
+    private final int size;
+    private int currentSize;
 
+    @SuppressWarnings("unchecked")
     public CircularQueue(int size) {
-        arr = new int[size];
-        topOfQueue = -1;
-        beginningOfQueue = -1;
+        this.array = (T[]) new Object[size];
+        this.topOfQueue = -1;
+        this.beginningOfQueue = -1;
         this.size = size;
+        this.currentSize = 0;
     }
 
     public boolean isEmpty() {
-        return beginningOfQueue == -1;
+        return currentSize == 0;
     }
 
     public boolean isFull() {
-        if (topOfQueue + 1 == beginningOfQueue) {
-            return true;
-        } else {
-            return topOfQueue == size - 1 && beginningOfQueue == 0;
-        }
+        return currentSize == size;
     }
 
-    public void enQueue(int value) {
+    public void enQueue(T value) {
         if (isFull()) {
-            System.out.println("The Queue is full!");
-        } else if (isEmpty()) {
+            throw new IllegalStateException("Queue is full");
+        }
+        if (isEmpty()) {
             beginningOfQueue = 0;
-            topOfQueue++;
-            arr[topOfQueue] = value;
-            System.out.println(value + " has been successfully inserted!");
-        } else {
-            if (topOfQueue + 1 == size) {
-                topOfQueue = 0;
-            } else {
-                topOfQueue++;
-            }
-            arr[topOfQueue] = value;
-            System.out.println(value + " has been successfully inserted!");
         }
+        topOfQueue = (topOfQueue + 1) % size;
+        array[topOfQueue] = value;
+        currentSize++;
     }
 
-    public int deQueue() {
+    public T deQueue() {
+        if (isEmpty()) {
+            throw new IllegalStateException("Queue is empty");
+        }
+        T removedValue = array[beginningOfQueue];
+        array[beginningOfQueue] = null; // Optional: Help GC
+        beginningOfQueue = (beginningOfQueue + 1) % size;
+        currentSize--;
         if (isEmpty()) {
-            System.out.println("The Queue is Empty!");
-            return -1;
-        } else {
-            int res = arr[beginningOfQueue];
-            arr[beginningOfQueue] = Integer.MIN_VALUE;
-            if (beginningOfQueue == topOfQueue) {
-                beginningOfQueue = -1;
-                topOfQueue = -1;
-            } else if (beginningOfQueue + 1 == size) {
-                beginningOfQueue = 0;
-            } else {
-                beginningOfQueue++;
-            }
-            return res;
+            beginningOfQueue = -1;
+            topOfQueue = -1;
         }
+        return removedValue;
     }
 
-    public int peek() {
+    public T peek() {
         if (isEmpty()) {
-            System.out.println("The Queue is Empty!");
-            return -1;
-        } else {
-            return arr[beginningOfQueue];
+            throw new IllegalStateException("Queue is empty");
         }
+        return array[beginningOfQueue];
     }
 
     public void deleteQueue() {
-        arr = null;
-        System.out.println("The Queue is deleted!");
+        array = null;
+        beginningOfQueue = -1;
+        topOfQueue = -1;
+        currentSize = 0;
+    }
+
+    public int size() {
+        return currentSize;
     }
 
     public static void main(String[] args) {
-        CircularQueue cq = new CircularQueue(5);
-        System.out.println(cq.isEmpty());
-        System.out.println(cq.isFull());
+        CircularQueue<Integer> cq = new CircularQueue<>(5);
+        System.out.println(cq.isEmpty()); // true
+        System.out.println(cq.isFull()); // false
         cq.enQueue(1);
         cq.enQueue(2);
         cq.enQueue(3);
         cq.enQueue(4);
         cq.enQueue(5);
 
-        System.out.println(cq.deQueue());
-        System.out.println(cq.deQueue());
-        System.out.println(cq.deQueue());
-        System.out.println(cq.deQueue());
-        System.out.println(cq.deQueue());
-        System.out.println(cq.isFull());
-        System.out.println(cq.isEmpty());
+        System.out.println(cq.deQueue()); // 1
+        System.out.println(cq.deQueue()); // 2
+        System.out.println(cq.deQueue()); // 3
+        System.out.println(cq.deQueue()); // 4
+        System.out.println(cq.deQueue()); // 5
+
+        System.out.println(cq.isFull()); // false
+        System.out.println(cq.isEmpty()); // true
         cq.enQueue(6);
         cq.enQueue(7);
         cq.enQueue(8);
-        System.out.println(cq.peek());
-        System.out.println(cq.peek());
+
+        System.out.println(cq.peek()); // 6
+        System.out.println(cq.peek()); // 6
+
         cq.deleteQueue();
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java b/src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java
new file mode 100644
index 000000000000..71dca8fdb538
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java
@@ -0,0 +1,106 @@
+package com.thealgorithms.datastructures.queues;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class CircularQueueTest {
+
+    @Test
+    void testEnQueue() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+        cq.enQueue(3);
+
+        assertEquals(1, cq.peek());
+        assertTrue(cq.isFull());
+    }
+
+    @Test
+    void testDeQueue() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+        cq.enQueue(3);
+
+        assertEquals(1, cq.deQueue());
+        assertEquals(2, cq.peek());
+        assertFalse(cq.isFull());
+    }
+
+    @Test
+    void testIsEmpty() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        assertTrue(cq.isEmpty());
+
+        cq.enQueue(1);
+        assertFalse(cq.isEmpty());
+    }
+
+    @Test
+    void testIsFull() {
+        CircularQueue<Integer> cq = new CircularQueue<>(2);
+        cq.enQueue(1);
+        cq.enQueue(2);
+        assertTrue(cq.isFull());
+
+        cq.deQueue();
+        assertFalse(cq.isFull());
+    }
+
+    @Test
+    void testPeek() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+
+        assertEquals(1, cq.peek());
+        assertEquals(1, cq.peek()); // Ensure peek doesn't remove the element
+    }
+
+    @Test
+    void testDeleteQueue() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+        cq.deleteQueue();
+
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalStateException.class, cq::peek);
+    }
+
+    @Test
+    void testEnQueueOnFull() {
+        CircularQueue<Integer> cq = new CircularQueue<>(2);
+        cq.enQueue(1);
+        cq.enQueue(2);
+
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalStateException.class, () -> cq.enQueue(3));
+    }
+
+    @Test
+    void testDeQueueOnEmpty() {
+        CircularQueue<Integer> cq = new CircularQueue<>(2);
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalStateException.class, cq::deQueue);
+    }
+
+    @Test
+    void testPeekOnEmpty() {
+        CircularQueue<Integer> cq = new CircularQueue<>(2);
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalStateException.class, cq::peek);
+    }
+
+    @Test
+    void testSize() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+
+        assertEquals(2, cq.size());
+
+        cq.deQueue();
+        assertEquals(1, cq.size());
+    }
+}

From a03353d3d3f5669b67763487f6d9018490fc9108 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 21 Aug 2024 12:39:01 +0200
Subject: [PATCH 0294/1338] refactor: `Deque` (#5353)

---
 .../queues/{Deques.java => Deque.java}        | 118 +++++-------------
 .../datastructures/queues/DequeTest.java      |  90 +++++++++++++
 2 files changed, 119 insertions(+), 89 deletions(-)
 rename src/main/java/com/thealgorithms/datastructures/queues/{Deques.java => Deque.java} (61%)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/Deques.java b/src/main/java/com/thealgorithms/datastructures/queues/Deque.java
similarity index 61%
rename from src/main/java/com/thealgorithms/datastructures/queues/Deques.java
rename to src/main/java/com/thealgorithms/datastructures/queues/Deque.java
index 5c4e9b641445..4cfa2b442ca0 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/Deques.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/Deque.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.datastructures.queues;
 
+import java.util.NoSuchElementException;
+
 /**
  * A [deque](https://en.wikipedia.org/wiki/Double-ended_queue) is short for a
  * double ended queue pronounced "deck" and sometimes referred to as a head-tail
@@ -9,50 +11,24 @@
  *
  * @author [Ian Cowan](https://github.com/iccowan)
  */
-public class Deques<T> {
+public class Deque<T> {
 
     /**
      * Node for the deque
      */
-    class DequeNode<S> {
-
-        /**
-         * Value of the node
-         */
+    private static class DequeNode<S> {
         S val;
-
-        /**
-         * Next node in the deque from this node
-         */
         DequeNode<S> next = null;
-
-        /**
-         * Previous node in the deque from this node
-         */
         DequeNode<S> prev = null;
 
-        /**
-         * Constructor
-         */
         DequeNode(S val) {
             this.val = val;
         }
     }
 
-    /**
-     * Head of the deque
-     */
-    DequeNode<T> head = null;
-
-    /**
-     * Tail of the deque
-     */
-    DequeNode<T> tail = null;
-
-    /**
-     * Size of the deque
-     */
-    int size = 0;
+    private DequeNode<T> head = null;
+    private DequeNode<T> tail = null;
+    private int size = 0;
 
     /**
      * Adds the specified value to the head of the deque
@@ -60,16 +36,12 @@ class DequeNode<S> {
      * @param val Value to add to the deque
      */
     public void addFirst(T val) {
-        // Create a new node with the given value
-        DequeNode<T> newNode = new DequeNode<T>(val);
+        DequeNode<T> newNode = new DequeNode<>(val);
 
-        // Add the node
-        if (head == null) {
-            // If the deque is empty, add the node as the head and tail
+        if (isEmpty()) {
             head = newNode;
             tail = newNode;
         } else {
-            // If the deque is not empty, insert the node as the new head
             newNode.next = head;
             head.prev = newNode;
             head = newNode;
@@ -84,20 +56,15 @@ public void addFirst(T val) {
      * @param val Value to add to the deque
      */
     public void addLast(T val) {
-        // Create a new node with the given value
-        DequeNode<T> newNode = new DequeNode<T>(val);
-
-        // Add the node
+        DequeNode<T> newNode = new DequeNode<>(val);
         if (tail == null) {
-            // If the deque is empty, add the node as the head and tail
             head = newNode;
+            tail = newNode;
         } else {
-            // If the deque is not empty, insert the node as the new tail
             newNode.prev = tail;
             tail.next = newNode;
+            tail = newNode;
         }
-        tail = newNode;
-
         size++;
     }
 
@@ -105,33 +72,21 @@ public void addLast(T val) {
      * Removes and returns the first (head) value in the deque
      *
      * @return the value of the head of the deque
+     * @throws NoSuchElementException if the deque is empty
      */
     public T pollFirst() {
-        // If the head is null, return null
         if (head == null) {
-            return null;
+            throw new NoSuchElementException("Deque is empty");
         }
 
-        // First, let's get the value of the old head
         T oldHeadVal = head.val;
-
-        // Now, let's remove the head
         if (head == tail) {
-            // If there is only one node, remove it
             head = null;
             tail = null;
         } else {
-            // If there is more than one node, fix the references
-            head.next.prev = null;
-            DequeNode<T> oldHead = head;
             head = head.next;
-
-            // Can be considered unnecessary...
-            // Unlinking the old head to make sure there are no random
-            // references possibly affecting garbage collection
-            oldHead.next = null;
+            head.prev = null;
         }
-
         size--;
         return oldHeadVal;
     }
@@ -140,32 +95,21 @@ public T pollFirst() {
      * Removes and returns the last (tail) value in the deque
      *
      * @return the value of the tail of the deque
+     * @throws NoSuchElementException if the deque is empty
      */
     public T pollLast() {
-        // If the tail is null, return null
         if (tail == null) {
-            return null;
+            throw new NoSuchElementException("Deque is empty");
         }
 
-        // Let's get the value of the old tail
         T oldTailVal = tail.val;
-
-        // Now, remove the tail
         if (head == tail) {
-            // If there is only one node, remove it
             head = null;
             tail = null;
         } else {
-            // If there is more than one node, fix the references
-            tail.prev.next = null;
-            DequeNode<T> oldTail = tail;
             tail = tail.prev;
-
-            // Similarly to above, can be considered unnecessary
-            // See `pollFirst()` for explanation
-            oldTail.prev = null;
+            tail.next = null;
         }
-
         size--;
         return oldTailVal;
     }
@@ -173,19 +117,19 @@ public T pollLast() {
     /**
      * Returns the first (head) value of the deque WITHOUT removing
      *
-     * @return the value of the head of the deque
+     * @return the value of the head of the deque, or null if empty
      */
     public T peekFirst() {
-        return head.val;
+        return head != null ? head.val : null;
     }
 
     /**
      * Returns the last (tail) value of the deque WITHOUT removing
      *
-     * @return the value of the tail of the deque
+     * @return the value of the tail of the deque, or null if empty
      */
     public T peekLast() {
-        return tail.val;
+        return tail != null ? tail.val : null;
     }
 
     /**
@@ -203,7 +147,7 @@ public int size() {
      * @return whether or not the deque is empty
      */
     public boolean isEmpty() {
-        return head == null;
+        return size == 0;
     }
 
     /**
@@ -216,25 +160,21 @@ public boolean isEmpty() {
      */
     @Override
     public String toString() {
-        String dequeString = "Head -> ";
+        StringBuilder dequeString = new StringBuilder("Head -> ");
         DequeNode<T> currNode = head;
         while (currNode != null) {
-            dequeString += currNode.val;
-
+            dequeString.append(currNode.val);
             if (currNode.next != null) {
-                dequeString += " <-> ";
+                dequeString.append(" <-> ");
             }
-
             currNode = currNode.next;
         }
-
-        dequeString += " <- Tail";
-
-        return dequeString;
+        dequeString.append(" <- Tail");
+        return dequeString.toString();
     }
 
     public static void main(String[] args) {
-        Deques<Integer> myDeque = new Deques<Integer>();
+        Deque<Integer> myDeque = new Deque<>();
         for (int i = 0; i < 42; i++) {
             if (i / 42.0 < 0.5) {
                 myDeque.addFirst(i);
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java b/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java
new file mode 100644
index 000000000000..1244a2e260d2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java
@@ -0,0 +1,90 @@
+package com.thealgorithms.datastructures.queues;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import java.util.NoSuchElementException;
+import org.junit.jupiter.api.Test;
+
+class DequeTest {
+
+    @Test
+    void testAddFirst() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addFirst(10);
+        assertEquals(10, deque.peekFirst());
+        assertEquals(10, deque.peekLast());
+        assertEquals(1, deque.size());
+    }
+
+    @Test
+    void testAddLast() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addLast(20);
+        assertEquals(20, deque.peekFirst());
+        assertEquals(20, deque.peekLast());
+        assertEquals(1, deque.size());
+    }
+
+    @Test
+    void testPollFirst() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addFirst(10);
+        deque.addLast(20);
+        assertEquals(10, deque.pollFirst());
+        assertEquals(20, deque.peekFirst());
+        assertEquals(1, deque.size());
+    }
+
+    @Test
+    void testPollLast() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addFirst(10);
+        deque.addLast(20);
+        assertEquals(20, deque.pollLast());
+        assertEquals(10, deque.peekLast());
+        assertEquals(1, deque.size());
+    }
+
+    @Test
+    void testIsEmpty() {
+        Deque<Integer> deque = new Deque<>();
+        org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty());
+        deque.addFirst(10);
+        assertFalse(deque.isEmpty());
+    }
+
+    @Test
+    void testPeekFirstEmpty() {
+        Deque<Integer> deque = new Deque<>();
+        assertNull(deque.peekFirst());
+    }
+
+    @Test
+    void testPeekLastEmpty() {
+        Deque<Integer> deque = new Deque<>();
+        assertNull(deque.peekLast());
+    }
+
+    @Test
+    void testPollFirstEmpty() {
+        Deque<Integer> deque = new Deque<>();
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, deque::pollFirst);
+    }
+
+    @Test
+    void testPollLastEmpty() {
+        Deque<Integer> deque = new Deque<>();
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, deque::pollLast);
+    }
+
+    @Test
+    void testToString() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addFirst(10);
+        deque.addLast(20);
+        deque.addFirst(5);
+        assertEquals("Head -> 5 <-> 10 <-> 20 <- Tail", deque.toString());
+    }
+}

From 4c6553072276a14ed73ca196922c9decde783f25 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 21 Aug 2024 13:00:05 +0200
Subject: [PATCH 0295/1338] refactor: `StackArrayList` (#5356)

---
 .../datastructures/stacks/StackArrayList.java | 102 ++++--------------
 .../stacks/StackArrayListTest.java            |  76 +++++++++++++
 2 files changed, 96 insertions(+), 82 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java b/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java
index 9506ae385733..088156a98f78 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java
@@ -6,110 +6,48 @@
 /**
  * This class implements a Stack using an ArrayList.
  *
- * <p>
- * A stack is exactly what it sounds like. An element gets added to the top of
- * the stack and only the element on the top may be removed.
- *
- * <p>
- * This is an ArrayList Implementation of a stack, where size is not a problem
- * we can extend the stack as much as we want.
+ * @param <T> the type of elements in this stack
  */
-public class StackArrayList {
-
-    /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        StackArrayList stack = new StackArrayList();
-        assert stack.isEmpty();
-
-        for (int i = 1; i <= 5; ++i) {
-            stack.push(i);
-            assert stack.size() == i;
-        }
-
-        assert stack.size() == 5;
-        assert stack.peek() == 5 && stack.pop() == 5 && stack.peek() == 4;
+public class StackArrayList<T> implements Stack<T> {
 
-        /* pop elements at the top of this stack one by one */
-        while (!stack.isEmpty()) {
-            stack.pop();
-        }
-        assert stack.isEmpty();
-
-        try {
-            stack.pop();
-            assert false;
-            /* this should not happen */
-        } catch (EmptyStackException e) {
-            assert true;
-            /* this should happen */
-        }
-    }
+    private final ArrayList<T> stack;
 
-    /**
-     * ArrayList representation of the stack
-     */
-    private ArrayList<Integer> stack;
-
-    /**
-     * Constructor
-     */
     public StackArrayList() {
         stack = new ArrayList<>();
     }
 
-    /**
-     * Adds value to the end of list which is the top for stack
-     *
-     * @param value value to be added
-     */
-    public void push(int value) {
+    @Override
+    public void push(T value) {
         stack.add(value);
     }
 
-    /**
-     * Removes the element at the top of this stack and returns
-     *
-     * @return Element popped
-     * @throws EmptyStackException if the stack is empty.
-     */
-    public int pop() {
+    @Override
+    public T pop() {
         if (isEmpty()) {
             throw new EmptyStackException();
         }
+        return stack.removeLast();
+    }
 
-        /* remove the element on the top of the stack */
-        return stack.remove(stack.size() - 1);
+    @Override
+    public T peek() {
+        if (isEmpty()) {
+            throw new EmptyStackException();
+        }
+        return stack.getLast();
     }
 
-    /**
-     * Test if the stack is empty.
-     *
-     * @return {@code true} if this stack is empty, {@code false} otherwise.
-     */
+    @Override
     public boolean isEmpty() {
         return stack.isEmpty();
     }
 
-    /**
-     * Return the element at the top of this stack without removing it from the
-     * stack.
-     *
-     * @return the element at the top of this stack.
-     */
-    public int peek() {
-        if (isEmpty()) {
-            throw new EmptyStackException();
-        }
-        return stack.get(stack.size() - 1);
+    @Override
+    public void makeEmpty() {
+        stack.clear();
     }
 
-    /**
-     * Return size of this stack.
-     *
-     * @return size of this stack.
-     */
+    @Override
     public int size() {
         return stack.size();
     }
diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java
new file mode 100644
index 000000000000..f4c261904bb4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java
@@ -0,0 +1,76 @@
+package com.thealgorithms.datastructures.stacks;
+
+import java.util.EmptyStackException;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class StackArrayListTest {
+
+    private StackArrayList<Integer> stack;
+
+    @BeforeEach
+    void setUp() {
+        stack = new StackArrayList<>();
+    }
+
+    @Test
+    void testPushAndPop() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+
+        Assertions.assertEquals(3, stack.pop());
+        Assertions.assertEquals(2, stack.pop());
+        Assertions.assertEquals(1, stack.pop());
+    }
+
+    @Test
+    void testPeek() {
+        stack.push(10);
+        stack.push(20);
+
+        Assertions.assertEquals(20, stack.peek());
+        stack.pop(); // Remove 20
+        Assertions.assertEquals(10, stack.peek());
+    }
+
+    @Test
+    void testIsEmpty() {
+        Assertions.assertTrue(stack.isEmpty());
+        stack.push(1);
+        Assertions.assertFalse(stack.isEmpty());
+        stack.pop();
+        Assertions.assertTrue(stack.isEmpty());
+    }
+
+    @Test
+    void testMakeEmpty() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+        stack.makeEmpty();
+        Assertions.assertTrue(stack.isEmpty());
+        Assertions.assertEquals(0, stack.size());
+    }
+
+    @Test
+    void testSize() {
+        Assertions.assertEquals(0, stack.size());
+        stack.push(1);
+        stack.push(2);
+        Assertions.assertEquals(2, stack.size());
+        stack.pop();
+        Assertions.assertEquals(1, stack.size());
+    }
+
+    @Test
+    void testPopEmptyStackThrowsException() {
+        Assertions.assertThrows(EmptyStackException.class, stack::pop);
+    }
+
+    @Test
+    void testPeekEmptyStackThrowsException() {
+        Assertions.assertThrows(EmptyStackException.class, stack::peek);
+    }
+}

From 39ecf708578c7c08d7c3773a43649cc6694bc362 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 21 Aug 2024 15:55:36 +0200
Subject: [PATCH 0296/1338] refactor: `GenericArrayListQueue` (#5355)

---
 .../queues/GenericArrayListQueue.java         | 64 +++++--------------
 .../queues/GenericArrayListQueueTest.java     | 55 ++++++++++++++++
 2 files changed, 72 insertions(+), 47 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java
index ec1e15e415b8..2a3a5a2c38e2 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.queues;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * This class implements a GenericArrayListQueue.
@@ -13,75 +14,44 @@
 public class GenericArrayListQueue<T> {
 
     /**
-     * The generic ArrayList for the queue T is the generic element
+     * The generic List for the queue. T is the generic element type.
      */
-    ArrayList<T> elementList = new ArrayList<>();
+    private final List<T> elementList = new ArrayList<>();
 
     /**
-     * Checks if the queue has elements (not empty).
+     * Checks if the queue is empty.
      *
-     * @return True if the queue has elements. False otherwise.
+     * @return True if the queue is empty, false otherwise.
      */
-    private boolean hasElements() {
-        return !elementList.isEmpty();
+    private boolean isEmpty() {
+        return elementList.isEmpty();
     }
 
     /**
-     * Checks what's at the front of the queue.
+     * Returns the element at the front of the queue without removing it.
      *
-     * @return If queue is not empty, element at the front of the queue.
-     * Otherwise, null
+     * @return The element at the front of the queue, or null if the queue is empty.
      */
     public T peek() {
-        T result = null;
-        if (this.hasElements()) {
-            result = elementList.get(0);
-        }
-        return result;
+        return isEmpty() ? null : elementList.getFirst();
     }
 
     /**
-     * Inserts an element of type T to the queue.
+     * Inserts an element of type T to the back of the queue.
      *
-     * @param element of type T to be added
-     * @return True if the element was added successfully
+     * @param element the element to be added to the queue.
+     * @return True if the element was added successfully.
      */
     public boolean add(T element) {
         return elementList.add(element);
     }
 
     /**
-     * Retrieve what's at the front of the queue
+     * Retrieves and removes the element at the front of the queue.
      *
-     * @return If queue is not empty, element retrieved. Otherwise, null
+     * @return The element removed from the front of the queue, or null if the queue is empty.
      */
-    public T pull() {
-        T result = null;
-        if (this.hasElements()) {
-            result = elementList.remove(0);
-        }
-        return result;
-    }
-
-    /**
-     * Main method
-     *
-     * @param args Command line arguments
-     */
-    public static void main(String[] args) {
-        GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
-        System.out.println("Running...");
-        assert queue.peek() == null;
-        assert queue.pull() == null;
-        assert queue.add(1);
-        assert queue.peek() == 1;
-        assert queue.add(2);
-        assert queue.peek() == 1;
-        assert queue.pull() == 1;
-        assert queue.peek() == 2;
-        assert queue.pull() == 2;
-        assert queue.peek() == null;
-        assert queue.pull() == null;
-        System.out.println("Finished.");
+    public T poll() {
+        return isEmpty() ? null : elementList.removeFirst();
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java b/src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java
new file mode 100644
index 000000000000..bb76b8317e62
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.datastructures.queues;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class GenericArrayListQueueTest {
+
+    @Test
+    void testAdd() {
+        GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
+        assertTrue(queue.add(10));
+        assertTrue(queue.add(20));
+    }
+
+    @Test
+    void testPeek() {
+        GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
+        assertNull(queue.peek());
+
+        queue.add(10);
+        queue.add(20);
+
+        assertEquals(10, queue.peek());
+        queue.poll();
+        assertEquals(20, queue.peek());
+    }
+
+    @Test
+    void testPoll() {
+        GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
+        assertNull(queue.poll());
+
+        queue.add(10);
+        queue.add(20);
+
+        assertEquals(10, queue.poll());
+        assertEquals(20, queue.poll());
+        assertNull(queue.poll());
+    }
+
+    @Test
+    void testIsEmpty() {
+        GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
+        assertNull(queue.peek());
+        assertNull(queue.poll());
+
+        queue.add(30);
+        assertEquals(30, queue.peek());
+        assertEquals(30, queue.poll());
+        assertNull(queue.peek());
+    }
+}

From 5149051e95aebba639b160297f8666f8cb16301d Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 21 Aug 2024 19:39:09 +0200
Subject: [PATCH 0297/1338] refactor: `LinkedQueue` (#5352)

---
 .../datastructures/queues/LinkedQueue.java    | 190 ++++++++--------
 .../queues/LinkedQueueTest.java               | 207 ++++++++++++++++--
 2 files changed, 280 insertions(+), 117 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
index 5fba2ff6a69c..6ba16199dbb8 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java
@@ -2,216 +2,200 @@
 
 import java.util.Iterator;
 import java.util.NoSuchElementException;
-import java.util.StringJoiner;
 
 public class LinkedQueue<T> implements Iterable<T> {
 
-    static class Node<T> {
-
+    /**
+     * Node class representing each element in the queue.
+     */
+    private static class Node<T> {
         T data;
         Node<T> next;
 
-        Node() {
-            this(null);
-        }
-
         Node(T data) {
-            this(data, null);
-        }
-
-        Node(T data, Node<T> next) {
             this.data = data;
-            this.next = next;
+            this.next = null;
         }
     }
 
-    /**
-     * Front of Queue
-     */
-    private Node<T> front;
-
-    /**
-     * Rear of Queue
-     */
-    private Node<T> rear;
+    private Node<T> front; // Front of the queue
+    private Node<T> rear; // Rear of the queue
+    private int size; // Size of the queue
 
     /**
-     * Size of Queue
-     */
-    private int size;
-
-    /**
-     * Init LinkedQueue
+     * Initializes an empty LinkedQueue.
      */
     public LinkedQueue() {
-
-        front = new Node<>();
-        rear = front;
+        front = null;
+        rear = null;
+        size = 0;
     }
 
     /**
-     * Check if queue is empty
+     * Checks if the queue is empty.
      *
-     * @return true if queue is empty, otherwise false
+     * @return true if the queue is empty, otherwise false.
      */
     public boolean isEmpty() {
         return size == 0;
     }
 
     /**
-     * Add element to rear of queue
+     * Adds an element to the rear of the queue.
      *
-     * @param data insert value
+     * @param data the element to insert.
+     * @throws IllegalArgumentException if data is null.
      */
     public void enqueue(T data) {
+        if (data == null) {
+            throw new IllegalArgumentException("Cannot enqueue null data");
+        }
+
         Node<T> newNode = new Node<>(data);
 
-        rear.next = newNode;
+        if (isEmpty()) {
+            front = newNode;
+        } else {
+            rear.next = newNode;
+        }
         rear = newNode;
-        /* make rear point at last node */
         size++;
     }
 
     /**
-     * Remove element at the front of queue
+     * Removes and returns the element at the front of the queue.
      *
-     * @return element at the front of queue
+     * @return the element at the front of the queue.
+     * @throws NoSuchElementException if the queue is empty.
      */
     public T dequeue() {
         if (isEmpty()) {
-            throw new NoSuchElementException("queue is empty");
+            throw new NoSuchElementException("Queue is empty");
         }
-        Node<T> destroy = front.next;
-        T retValue = destroy.data;
-        front.next = front.next.next;
-        /* clear let GC do it's work */
+
+        T retValue = front.data;
+        front = front.next;
         size--;
 
         if (isEmpty()) {
-            front = rear;
+            rear = null;
         }
 
         return retValue;
     }
 
     /**
-     * Peek element at the front of queue without removing
+     * Returns the element at the front of the queue without removing it.
      *
-     * @return element at the front
+     * @return the element at the front of the queue.
+     * @throws NoSuchElementException if the queue is empty.
      */
     public T peekFront() {
         if (isEmpty()) {
-            throw new NoSuchElementException("queue is empty");
+            throw new NoSuchElementException("Queue is empty");
         }
-        return front.next.data;
+        return front.data;
     }
 
     /**
-     * Peek element at the rear of queue without removing
+     * Returns the element at the rear of the queue without removing it.
      *
-     * @return element at the front
+     * @return the element at the rear of the queue.
+     * @throws NoSuchElementException if the queue is empty.
      */
     public T peekRear() {
         if (isEmpty()) {
-            throw new NoSuchElementException("queue is empty");
+            throw new NoSuchElementException("Queue is empty");
         }
         return rear.data;
     }
 
     /**
-     * Peeks the element at the index and
-     *          returns the value
-     * @param pos at which to peek
+     * Returns the element at the specified position (1-based index).
+     *
+     * @param pos the position to peek at (1-based index).
+     * @return the element at the specified position.
+     * @throws IndexOutOfBoundsException if the position is out of range.
      */
-
     public T peek(int pos) {
-        if (pos > size) {
-            throw new IndexOutOfBoundsException("Position %s out of range!".formatted(pos));
+        if (pos < 1 || pos > size) {
+            throw new IndexOutOfBoundsException("Position " + pos + " out of range!");
         }
+
         Node<T> node = front;
-        while (pos-- > 0) {
+        for (int i = 1; i < pos; i++) {
             node = node.next;
         }
         return node.data;
     }
 
     /**
-     * Node iterator, allows to travel through
-     * the nodes using for() loop or forEach(Consumer)
+     * Returns an iterator over the elements in the queue.
+     *
+     * @return an iterator over the elements in the queue.
      */
-
     @Override
     public Iterator<T> iterator() {
         return new Iterator<>() {
-            Node<T> node = front;
+            private Node<T> current = front;
 
             @Override
             public boolean hasNext() {
-                return node.next != null;
+                return current != null;
             }
 
             @Override
             public T next() {
-                if (hasNext()) {
-                    node = node.next;
-                    return node.data;
+                if (!hasNext()) {
+                    throw new NoSuchElementException();
                 }
-                throw new NoSuchElementException();
+
+                T data = current.data;
+                current = current.next;
+                return data;
             }
         };
     }
 
     /**
-     * Return size of queue
+     * Returns the size of the queue.
      *
-     * @return size of queue
+     * @return the size of the queue.
      */
     public int size() {
         return size;
     }
 
     /**
-     * Clear all nodes in queue
+     * Clears all elements from the queue.
      */
     public void clear() {
-        while (size > 0) {
-            dequeue();
-        }
+        front = null;
+        rear = null;
+        size = 0;
     }
 
+    /**
+     * Returns a string representation of the queue.
+     *
+     * @return a string representation of the queue.
+     */
     @Override
     public String toString() {
-        StringJoiner join = new StringJoiner(", "); // separator of ', '
-        Node<T> travel = front;
-        while ((travel = travel.next) != null) {
-            join.add(String.valueOf(travel.data));
+        if (isEmpty()) {
+            return "[]";
         }
-        return '[' + join.toString() + ']';
-    }
 
-    /* Driver Code */
-    public static void main(String[] args) {
-        LinkedQueue<Integer> queue = new LinkedQueue<>();
-        assert queue.isEmpty();
-
-        queue.enqueue(1);
-        /* 1 */
-        queue.enqueue(2);
-        /* 1 2 */
-        queue.enqueue(3);
-        /* 1 2 3 */
-        System.out.println(queue);
-        /* [1, 2, 3] */
-
-        assert queue.size() == 3;
-        assert queue.dequeue() == 1;
-        assert queue.peekFront() == 2;
-        assert queue.peekRear() == 3;
-
-        queue.clear();
-        assert queue.isEmpty();
-
-        System.out.println(queue);
-        /* [] */
+        StringBuilder sb = new StringBuilder("[");
+        Node<T> current = front;
+        while (current != null) {
+            sb.append(current.data);
+            if (current.next != null) {
+                sb.append(", ");
+            }
+            current = current.next;
+        }
+        sb.append(']');
+        return sb.toString();
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java b/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java
index 7bebf13e9620..157d771b5a80 100644
--- a/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java
@@ -1,30 +1,209 @@
 package com.thealgorithms.datastructures.queues;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 class LinkedQueueTest {
+
+    private LinkedQueue<Integer> queue;
+
+    @BeforeEach
+    void setUp() {
+        queue = new LinkedQueue<>();
+    }
+
+    @Test
+    void testIsEmptyOnNewQueue() {
+        assertTrue(queue.isEmpty(), "Queue should be empty on initialization.");
+    }
+
+    @Test
+    void testEnqueueAndSize() {
+        queue.enqueue(10);
+        assertFalse(queue.isEmpty(), "Queue should not be empty after enqueue.");
+        assertEquals(1, queue.size(), "Queue size should be 1 after one enqueue.");
+
+        queue.enqueue(20);
+        queue.enqueue(30);
+        assertEquals(3, queue.size(), "Queue size should be 3 after three enqueues.");
+    }
+
+    @Test
+    void testDequeueOnSingleElementQueue() {
+        queue.enqueue(10);
+        assertEquals(10, queue.dequeue(), "Dequeued element should be the same as the enqueued one.");
+        assertTrue(queue.isEmpty(), "Queue should be empty after dequeueing the only element.");
+    }
+
+    @Test
+    void testDequeueMultipleElements() {
+        queue.enqueue(10);
+        queue.enqueue(20);
+        queue.enqueue(30);
+
+        assertEquals(10, queue.dequeue(), "First dequeued element should be the first enqueued one.");
+        assertEquals(20, queue.dequeue(), "Second dequeued element should be the second enqueued one.");
+        assertEquals(30, queue.dequeue(), "Third dequeued element should be the third enqueued one.");
+        assertTrue(queue.isEmpty(), "Queue should be empty after dequeueing all elements.");
+    }
+
+    @Test
+    void testDequeueOnEmptyQueue() {
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, () -> queue.dequeue(), "Dequeueing from an empty queue should throw NoSuchElementException.");
+    }
+
+    @Test
+    void testPeekFrontOnEmptyQueue() {
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, () -> queue.peekFront(), "Peeking front on an empty queue should throw NoSuchElementException.");
+    }
+
     @Test
-    public void testQue() {
-        LinkedQueue<Integer> queue = new LinkedQueue<>();
-        for (int i = 1; i < 5; i++) {
+    void testPeekRearOnEmptyQueue() {
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, () -> queue.peekRear(), "Peeking rear on an empty queue should throw NoSuchElementException.");
+    }
+
+    @Test
+    void testPeekFront() {
+        queue.enqueue(10);
+        queue.enqueue(20);
+        queue.enqueue(30);
+
+        assertEquals(10, queue.peekFront(), "Peek front should return the first enqueued element.");
+        assertEquals(10, queue.peekFront(), "Peek front should not remove the element.");
+        assertEquals(3, queue.size(), "Queue size should remain unchanged after peek.");
+    }
+
+    @Test
+    void testPeekRear() {
+        queue.enqueue(10);
+        queue.enqueue(20);
+        queue.enqueue(30);
+
+        assertEquals(30, queue.peekRear(), "Peek rear should return the last enqueued element.");
+        assertEquals(30, queue.peekRear(), "Peek rear should not remove the element.");
+        assertEquals(3, queue.size(), "Queue size should remain unchanged after peek.");
+    }
+
+    @Test
+    void testPeekAtPosition() {
+        queue.enqueue(10);
+        queue.enqueue(20);
+        queue.enqueue(30);
+
+        assertEquals(10, queue.peek(1), "Peek at position 1 should return the first enqueued element.");
+        assertEquals(20, queue.peek(2), "Peek at position 2 should return the second enqueued element.");
+        assertEquals(30, queue.peek(3), "Peek at position 3 should return the third enqueued element.");
+    }
+
+    @Test
+    void testPeekAtInvalidPosition() {
+        queue.enqueue(10);
+        queue.enqueue(20);
+        queue.enqueue(30);
+
+        org.junit.jupiter.api.Assertions.assertThrows(IndexOutOfBoundsException.class, () -> queue.peek(4), "Peeking at a position greater than size should throw IndexOutOfBoundsException.");
+        org.junit.jupiter.api.Assertions.assertThrows(IndexOutOfBoundsException.class, () -> queue.peek(0), "Peeking at position 0 should throw IndexOutOfBoundsException.");
+    }
+
+    @Test
+    void testClearQueue() {
+        queue.enqueue(10);
+        queue.enqueue(20);
+        queue.enqueue(30);
+
+        queue.clear();
+        assertTrue(queue.isEmpty(), "Queue should be empty after clear.");
+        assertEquals(0, queue.size(), "Queue size should be 0 after clear.");
+    }
+
+    @Test
+    void testIterator() {
+        queue.enqueue(10);
+        queue.enqueue(20);
+        queue.enqueue(30);
+
+        Iterator<Integer> it = queue.iterator();
+        assertTrue(it.hasNext(), "Iterator should have next element.");
+        assertEquals(10, it.next(), "First iterator value should be the first enqueued element.");
+        assertEquals(20, it.next(), "Second iterator value should be the second enqueued element.");
+        assertEquals(30, it.next(), "Third iterator value should be the third enqueued element.");
+        assertFalse(it.hasNext(), "Iterator should not have next element after last element.");
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, it::next, "Calling next() on exhausted iterator should throw NoSuchElementException.");
+    }
+
+    @Test
+    void testToString() {
+        queue.enqueue(10);
+        queue.enqueue(20);
+        queue.enqueue(30);
+
+        assertEquals("[10, 20, 30]", queue.toString(), "toString should return a properly formatted string representation of the queue.");
+    }
+
+    @Test
+    void testEnqueueAfterDequeue() {
+        queue.enqueue(10);
+        queue.enqueue(20);
+        queue.enqueue(30);
+
+        assertEquals(10, queue.dequeue(), "Dequeued element should be 10.");
+        assertEquals(20, queue.dequeue(), "Dequeued element should be 20.");
+
+        queue.enqueue(40);
+        assertEquals(30, queue.peekFront(), "Peek front should return 30 after dequeuing and enqueuing new elements.");
+        assertEquals(40, queue.peekRear(), "Peek rear should return 40 after enqueuing new elements.");
+    }
+
+    @Test
+    void testQueueMaintainsOrder() {
+        for (int i = 1; i <= 100; i++) {
             queue.enqueue(i);
         }
 
-        assertEquals(queue.peekRear(), 4);
-        assertEquals(queue.peek(2), 2);
+        for (int i = 1; i <= 100; i++) {
+            assertEquals(i, queue.dequeue(), "Queue should maintain the correct order of elements.");
+        }
+
+        assertTrue(queue.isEmpty(), "Queue should be empty after dequeuing all elements.");
+    }
+
+    @Test
+    void testSizeAfterOperations() {
+        assertEquals(0, queue.size(), "Initial queue size should be 0.");
+
+        queue.enqueue(10);
+        assertEquals(1, queue.size(), "Queue size should be 1 after one enqueue.");
 
-        assertEquals(queue.peek(4), 4);
+        queue.enqueue(20);
+        assertEquals(2, queue.size(), "Queue size should be 2 after two enqueues.");
 
-        final int[] element = {1};
+        queue.dequeue();
+        assertEquals(1, queue.size(), "Queue size should be 1 after one dequeue.");
 
-        // iterates over all the elements present
-        // as in the form of nodes
-        queue.forEach(integer -> {
-            if (element[0]++ != integer) {
-                throw new AssertionError();
-            }
-        });
+        queue.clear();
+        assertEquals(0, queue.size(), "Queue size should be 0 after clear.");
+    }
+
+    @Test
+    void testQueueToStringOnEmptyQueue() {
+        assertEquals("[]", queue.toString(), "toString on empty queue should return '[]'.");
+    }
+
+    @Test
+    void testEnqueueNull() {
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalArgumentException.class, () -> queue.enqueue(null), "Cannot enqueue null data.");
+    }
+
+    @Test
+    void testIteratorOnEmptyQueue() {
+        Iterator<Integer> it = queue.iterator();
+        assertFalse(it.hasNext(), "Iterator on empty queue should not have next element.");
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, it::next, "Calling next() on empty queue iterator should throw NoSuchElementException.");
     }
 }

From 07dbc51e1b1513bc67d57171ea57c95ca45cf937 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 22 Aug 2024 08:43:52 +0200
Subject: [PATCH 0298/1338] feat: add temperature unit conversions (#5315)

Co-authored-by: Bama Charan Chhandogi <b.c.chhandogi@gmail.com>
---
 .../conversions/AffineConverter.java          | 23 +++++
 .../conversions/UnitConversions.java          | 14 +++
 .../conversions/UnitsConverter.java           | 86 +++++++++++++++++++
 .../conversions/UnitConversionsTest.java      | 48 +++++++++++
 .../conversions/UnitsConverterTest.java       | 18 ++++
 5 files changed, 189 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/AffineConverter.java
 create mode 100644 src/main/java/com/thealgorithms/conversions/UnitConversions.java
 create mode 100644 src/main/java/com/thealgorithms/conversions/UnitsConverter.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java

diff --git a/src/main/java/com/thealgorithms/conversions/AffineConverter.java b/src/main/java/com/thealgorithms/conversions/AffineConverter.java
new file mode 100644
index 000000000000..a580b23f90f9
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/AffineConverter.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.conversions;
+
+public final class AffineConverter {
+    private final double slope;
+    private final double intercept;
+    public AffineConverter(final double inSlope, final double inIntercept) {
+        slope = inSlope;
+        intercept = inIntercept;
+    }
+
+    public double convert(final double inValue) {
+        return slope * inValue + intercept;
+    }
+
+    public AffineConverter invert() {
+        assert slope != 0.0;
+        return new AffineConverter(1.0 / slope, -intercept / slope);
+    }
+
+    public AffineConverter compose(final AffineConverter other) {
+        return new AffineConverter(slope * other.slope, slope * other.intercept + intercept);
+    }
+}
diff --git a/src/main/java/com/thealgorithms/conversions/UnitConversions.java b/src/main/java/com/thealgorithms/conversions/UnitConversions.java
new file mode 100644
index 000000000000..abc06a0f8863
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/UnitConversions.java
@@ -0,0 +1,14 @@
+package com.thealgorithms.conversions;
+
+import static java.util.Map.entry;
+
+import java.util.Map;
+import org.apache.commons.lang3.tuple.Pair;
+
+public final class UnitConversions {
+    private UnitConversions() {
+    }
+
+    public static final UnitsConverter TEMPERATURE = new UnitsConverter(Map.ofEntries(entry(Pair.of("Kelvin", "Celsius"), new AffineConverter(1.0, -273.15)), entry(Pair.of("Celsius", "Fahrenheit"), new AffineConverter(9.0 / 5.0, 32.0)),
+        entry(Pair.of("Réaumur", "Celsius"), new AffineConverter(5.0 / 4.0, 0.0)), entry(Pair.of("Delisle", "Celsius"), new AffineConverter(-2.0 / 3.0, 100.0)), entry(Pair.of("Rankine", "Kelvin"), new AffineConverter(5.0 / 9.0, 0.0))));
+}
diff --git a/src/main/java/com/thealgorithms/conversions/UnitsConverter.java b/src/main/java/com/thealgorithms/conversions/UnitsConverter.java
new file mode 100644
index 000000000000..a19d40285047
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/UnitsConverter.java
@@ -0,0 +1,86 @@
+package com.thealgorithms.conversions;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import org.apache.commons.lang3.tuple.Pair;
+
+public final class UnitsConverter {
+    private final Map<Pair<String, String>, AffineConverter> conversions;
+    private final Set<String> units;
+
+    private static void putIfNeeded(Map<Pair<String, String>, AffineConverter> conversions, final String inputUnit, final String outputUnit, final AffineConverter converter) {
+        if (!inputUnit.equals(outputUnit)) {
+            final var key = Pair.of(inputUnit, outputUnit);
+            conversions.putIfAbsent(key, converter);
+        }
+    }
+
+    private static Map<Pair<String, String>, AffineConverter> addInversions(final Map<Pair<String, String>, AffineConverter> knownConversions) {
+        Map<Pair<String, String>, AffineConverter> res = new HashMap<Pair<String, String>, AffineConverter>();
+        for (final var curConversion : knownConversions.entrySet()) {
+            final var inputUnit = curConversion.getKey().getKey();
+            final var outputUnit = curConversion.getKey().getValue();
+            putIfNeeded(res, inputUnit, outputUnit, curConversion.getValue());
+            putIfNeeded(res, outputUnit, inputUnit, curConversion.getValue().invert());
+        }
+        return res;
+    }
+
+    private static Map<Pair<String, String>, AffineConverter> addCompositions(final Map<Pair<String, String>, AffineConverter> knownConversions) {
+        Map<Pair<String, String>, AffineConverter> res = new HashMap<Pair<String, String>, AffineConverter>();
+        for (final var first : knownConversions.entrySet()) {
+            final var firstKey = first.getKey();
+            putIfNeeded(res, firstKey.getKey(), firstKey.getValue(), first.getValue());
+            for (final var second : knownConversions.entrySet()) {
+                final var secondKey = second.getKey();
+                if (firstKey.getValue().equals(secondKey.getKey())) {
+                    final var newConversion = second.getValue().compose(first.getValue());
+                    putIfNeeded(res, firstKey.getKey(), secondKey.getValue(), newConversion);
+                }
+            }
+        }
+        return res;
+    }
+
+    private static Map<Pair<String, String>, AffineConverter> addAll(final Map<Pair<String, String>, AffineConverter> knownConversions) {
+        final var res = addInversions(knownConversions);
+        return addCompositions(res);
+    }
+
+    private static Map<Pair<String, String>, AffineConverter> computeAllConversions(final Map<Pair<String, String>, AffineConverter> basicConversions) {
+        var tmp = basicConversions;
+        var res = addAll(tmp);
+        while (res.size() != tmp.size()) {
+            tmp = res;
+            res = addAll(tmp);
+        }
+        return res;
+    }
+
+    private static Set<String> extractUnits(final Map<Pair<String, String>, AffineConverter> conversions) {
+        Set<String> res = new HashSet<>();
+        for (final var conversion : conversions.entrySet()) {
+            res.add(conversion.getKey().getKey());
+        }
+        return res;
+    }
+
+    public UnitsConverter(final Map<Pair<String, String>, AffineConverter> basicConversions) {
+        conversions = computeAllConversions(basicConversions);
+        units = extractUnits(conversions);
+    }
+
+    public double convert(final String inputUnit, final String outputUnit, final double value) {
+        if (inputUnit.equals(outputUnit)) {
+            throw new IllegalArgumentException("inputUnit must be different from outputUnit.");
+        }
+        final var conversionKey = Pair.of(inputUnit, outputUnit);
+        return conversions.get(conversionKey).convert(value);
+    }
+
+    public Set<String> availableUnits() {
+        return units;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java b/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java
new file mode 100644
index 000000000000..073e7d6de2c6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.conversions;
+
+import static java.util.Map.entry;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class UnitConversionsTest {
+    private static void addData(Stream.Builder<Arguments> builder, Map<String, Double> values) {
+        for (final var first : values.entrySet()) {
+            for (final var second : values.entrySet()) {
+                if (!first.getKey().equals(second.getKey())) {
+                    builder.add(Arguments.of(first.getKey(), second.getKey(), first.getValue(), second.getValue()));
+                }
+            }
+        }
+    }
+
+    private static Stream<Arguments> temperatureData() {
+        final Map<String, Double> boilingPointOfWater = Map.ofEntries(entry("Celsius", 99.9839), entry("Fahrenheit", 211.97102), entry("Kelvin", 373.1339), entry("Réaumur", 79.98712), entry("Delisle", 0.02415), entry("Rankine", 671.64102));
+
+        final Map<String, Double> freezingPointOfWater = Map.ofEntries(entry("Celsius", 0.0), entry("Fahrenheit", 32.0), entry("Kelvin", 273.15), entry("Réaumur", 0.0), entry("Delisle", 150.0), entry("Rankine", 491.67));
+
+        Stream.Builder<Arguments> builder = Stream.builder();
+        addData(builder, boilingPointOfWater);
+        addData(builder, freezingPointOfWater);
+        return builder.build();
+    }
+
+    @ParameterizedTest
+    @MethodSource("temperatureData")
+    void testTemperature(String inputUnit, String outputUnit, double value, double expected) {
+        final double result = UnitConversions.TEMPERATURE.convert(inputUnit, outputUnit, value);
+        assertEquals(expected, result, 0.00001);
+    }
+
+    @Test
+    void testTemperatureUnits() {
+        final Set<String> expectedUnits = Set.of("Celsius", "Fahrenheit", "Kelvin", "Réaumur", "Rankine", "Delisle");
+        assertEquals(expectedUnits, UnitConversions.TEMPERATURE.availableUnits());
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java b/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java
new file mode 100644
index 000000000000..76e48f144fd6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java
@@ -0,0 +1,18 @@
+package com.thealgorithms.conversions;
+
+import static java.util.Map.entry;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.Map;
+import org.apache.commons.lang3.tuple.Pair;
+import org.junit.jupiter.api.Test;
+
+public class UnitsConverterTest {
+
+    @Test
+    void testConvertThrowsForSameUnits() {
+        final UnitsConverter someConverter = new UnitsConverter(Map.ofEntries(entry(Pair.of("A", "B"), new AffineConverter(10.0, -20.0))));
+        assertThrows(IllegalArgumentException.class, () -> someConverter.convert("A", "A", 20.0));
+        assertThrows(IllegalArgumentException.class, () -> someConverter.convert("B", "B", 20.0));
+    }
+}

From 3ed8561a5fea582a94ac3ccce90a50f4112463aa Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 22 Aug 2024 09:12:44 +0200
Subject: [PATCH 0299/1338] test: `GCDRecursion` (#5361)

---
 .../thealgorithms/maths/GCDRecursionTest.java | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/maths/GCDRecursionTest.java

diff --git a/src/test/java/com/thealgorithms/maths/GCDRecursionTest.java b/src/test/java/com/thealgorithms/maths/GCDRecursionTest.java
new file mode 100644
index 000000000000..6b6ea2f85164
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/GCDRecursionTest.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+public class GCDRecursionTest {
+
+    @ParameterizedTest
+    @CsvSource({"7, 5, 1", "9, 12, 3", "18, 24, 6", "36, 60, 12"})
+    void testGcdPositiveNumbers(int a, int b, int expectedGcd) {
+        assertEquals(expectedGcd, GCDRecursion.gcd(a, b));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"0, 5, 5", "8, 0, 8"})
+    void testGcdOneZero(int a, int b, int expectedGcd) {
+        assertEquals(expectedGcd, GCDRecursion.gcd(a, b));
+    }
+
+    @Test
+    void testGcdBothZero() {
+        assertEquals(0, GCDRecursion.gcd(0, 0));
+    }
+
+    @ParameterizedTest
+    @ValueSource(ints = {-5, -15})
+    void testGcdNegativeNumbers(int negativeValue) {
+        assertThrows(ArithmeticException.class, () -> GCDRecursion.gcd(negativeValue, 15));
+        assertThrows(ArithmeticException.class, () -> GCDRecursion.gcd(15, negativeValue));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"5, 5, 5", "8, 8, 8"})
+    void testGcdWithSameNumbers(int a, int b, int expectedGcd) {
+        assertEquals(expectedGcd, GCDRecursion.gcd(a, b));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"7, 13, 1", "11, 17, 1"})
+    void testGcdWithPrimeNumbers(int a, int b, int expectedGcd) {
+        assertEquals(expectedGcd, GCDRecursion.gcd(a, b));
+    }
+}

From 3398c562a1d2df51b298adfcd714e1abb56b59dd Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 22 Aug 2024 09:44:01 +0200
Subject: [PATCH 0300/1338] test: `LargestRectangle` (#5360)

---
 .../stacks/LargestRectangleTest.java          | 77 +++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java

diff --git a/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java b/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java
new file mode 100644
index 000000000000..023f20a159f1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java
@@ -0,0 +1,77 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class LargestRectangleTest {
+
+    @Test
+    void testLargestRectangleHistogramWithTypicalCases() {
+        // Typical case with mixed heights
+        int[] heights = {2, 1, 5, 6, 2, 3};
+        String expected = "10";
+        String result = LargestRectangle.largestRectanglehistogram(heights);
+        assertEquals(expected, result);
+
+        // Another typical case with increasing heights
+        heights = new int[] {2, 4};
+        expected = "4";
+        result = LargestRectangle.largestRectanglehistogram(heights);
+        assertEquals(expected, result);
+
+        // Case with multiple bars of the same height
+        heights = new int[] {4, 4, 4, 4};
+        expected = "16";
+        result = LargestRectangle.largestRectanglehistogram(heights);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testLargestRectangleHistogramWithEdgeCases() {
+        // Edge case with an empty array
+        int[] heights = {};
+        String expected = "0";
+        String result = LargestRectangle.largestRectanglehistogram(heights);
+        assertEquals(expected, result);
+
+        // Edge case with a single bar
+        heights = new int[] {5};
+        expected = "5";
+        result = LargestRectangle.largestRectanglehistogram(heights);
+        assertEquals(expected, result);
+
+        // Edge case with all bars of height 0
+        heights = new int[] {0, 0, 0};
+        expected = "0";
+        result = LargestRectangle.largestRectanglehistogram(heights);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testLargestRectangleHistogramWithLargeInput() {
+        // Large input case
+        int[] heights = new int[10000];
+        for (int i = 0; i < heights.length; i++) {
+            heights[i] = 1;
+        }
+        String expected = "10000";
+        String result = LargestRectangle.largestRectanglehistogram(heights);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testLargestRectangleHistogramWithComplexCases() {
+        // Complex case with a mix of heights
+        int[] heights = {6, 2, 5, 4, 5, 1, 6};
+        String expected = "12";
+        String result = LargestRectangle.largestRectanglehistogram(heights);
+        assertEquals(expected, result);
+
+        // Case with a peak in the middle
+        heights = new int[] {2, 1, 5, 6, 2, 3, 1};
+        expected = "10";
+        result = LargestRectangle.largestRectanglehistogram(heights);
+        assertEquals(expected, result);
+    }
+}

From 8a89b42cf8de5518be850ea2a23daa922ae6afd9 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 22 Aug 2024 09:50:56 +0200
Subject: [PATCH 0301/1338] refactor: `AnyBaseToDecimal` (#5357)

---
 .../conversions/AnyBaseToDecimal.java         | 60 +++++++++----------
 .../conversions/AnyBaseToDecimalTest.java     | 22 +++++++
 2 files changed, 50 insertions(+), 32 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java

diff --git a/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java b/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java
index 6b4b14adc955..cdab98c7c28a 100644
--- a/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java
@@ -3,54 +3,50 @@
 /**
  * @author Varun Upadhyay (<a href="https://github.com/varunu28">...</a>)
  */
-// Driver program
 public final class AnyBaseToDecimal {
-    private AnyBaseToDecimal() {
-    }
+    private static final int CHAR_OFFSET_FOR_DIGIT = '0';
+    private static final int CHAR_OFFSET_FOR_UPPERCASE = 'A' - 10;
 
-    public static void main(String[] args) {
-        assert convertToDecimal("1010", 2) == Integer.valueOf("1010", 2);
-        assert convertToDecimal("777", 8) == Integer.valueOf("777", 8);
-        assert convertToDecimal("999", 10) == Integer.valueOf("999", 10);
-        assert convertToDecimal("ABCDEF", 16) == Integer.valueOf("ABCDEF", 16);
-        assert convertToDecimal("XYZ", 36) == Integer.valueOf("XYZ", 36);
+    private AnyBaseToDecimal() {
     }
 
     /**
-     * Convert any radix to decimal number
+     * Convert any radix to a decimal number.
      *
-     * @param s the string to be convert
-     * @param radix the radix
-     * @return decimal of bits
-     * @throws NumberFormatException if {@code bits} or {@code radix} is invalid
+     * @param input the string to be converted
+     * @param radix the radix (base) of the input string
+     * @return the decimal equivalent of the input string
+     * @throws NumberFormatException if the input string or radix is invalid
      */
-    public static int convertToDecimal(String s, int radix) {
-        int num = 0;
-        int pow = 1;
+    public static int convertToDecimal(String input, int radix) {
+        int result = 0;
+        int power = 1;
 
-        for (int i = s.length() - 1; i >= 0; i--) {
-            int digit = valOfChar(s.charAt(i));
+        for (int i = input.length() - 1; i >= 0; i--) {
+            int digit = valOfChar(input.charAt(i));
             if (digit >= radix) {
-                throw new NumberFormatException("For input string " + s);
+                throw new NumberFormatException("For input string: " + input);
             }
-            num += valOfChar(s.charAt(i)) * pow;
-            pow *= radix;
+            result += digit * power;
+            power *= radix;
         }
-        return num;
+        return result;
     }
 
     /**
-     * Convert character to integer
+     * Convert a character to its integer value.
      *
-     * @param c the character
-     * @return represented digit of given character
-     * @throws NumberFormatException if {@code ch} is not UpperCase or Digit
-     * character.
+     * @param character the character to be converted
+     * @return the integer value represented by the character
+     * @throws NumberFormatException if the character is not an uppercase letter or a digit
      */
-    public static int valOfChar(char c) {
-        if (!(Character.isUpperCase(c) || Character.isDigit(c))) {
-            throw new NumberFormatException("invalid character :" + c);
+    private static int valOfChar(char character) {
+        if (Character.isDigit(character)) {
+            return character - CHAR_OFFSET_FOR_DIGIT;
+        } else if (Character.isUpperCase(character)) {
+            return character - CHAR_OFFSET_FOR_UPPERCASE;
+        } else {
+            throw new NumberFormatException("invalid character:" + character);
         }
-        return Character.isDigit(c) ? c - '0' : c - 'A' + 10;
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java b/src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java
new file mode 100644
index 000000000000..c7f9493ef0e7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class AnyBaseToDecimalTest {
+    @ParameterizedTest
+    @CsvSource({"1010, 2, 10", "777, 8, 511", "999, 10, 999", "ABCDEF, 16, 11259375", "XYZ, 36, 44027", "0, 2, 0", "A, 16, 10", "Z, 36, 35"})
+    void testConvertToDecimal(String input, int radix, int expected) {
+        assertEquals(expected, AnyBaseToDecimal.convertToDecimal(input, radix));
+    }
+
+    @Test
+    void testIncorrectInput() {
+        assertThrows(NumberFormatException.class, () -> AnyBaseToDecimal.convertToDecimal("G", 16));
+        assertThrows(NumberFormatException.class, () -> AnyBaseToDecimal.convertToDecimal("XYZ", 10));
+    }
+}

From 622a3bf795ecd8e20348136e8f83a13bd19405ee Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 22 Aug 2024 10:08:17 +0200
Subject: [PATCH 0302/1338] refactor: cleanup `AhoCorasick` (#5358)

---
 .../thealgorithms/strings/AhoCorasick.java    | 35 +++++++++----------
 .../strings/AhoCorasickTest.java              | 11 +++---
 2 files changed, 22 insertions(+), 24 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/AhoCorasick.java b/src/main/java/com/thealgorithms/strings/AhoCorasick.java
index 6381830cb0bc..a68d0823a00d 100644
--- a/src/main/java/com/thealgorithms/strings/AhoCorasick.java
+++ b/src/main/java/com/thealgorithms/strings/AhoCorasick.java
@@ -14,6 +14,7 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.LinkedList;
+import java.util.List;
 import java.util.Map;
 import java.util.Queue;
 
@@ -24,7 +25,7 @@ private AhoCorasick() {
     // Trie Node Class
     private static class Node {
         // Represents a character in the trie
-        private HashMap<Character, Node> child = new HashMap<>(); // Child nodes of the current node
+        private final Map<Character, Node> child = new HashMap<>(); // Child nodes of the current node
         private Node suffixLink; // Suffix link to another node in the trie
         private Node outputLink; // Output link to another node in the trie
         private int patternInd; // Index of the pattern that ends at this node
@@ -35,7 +36,7 @@ private static class Node {
             this.patternInd = -1;
         }
 
-        public HashMap<Character, Node> getChild() {
+        public Map<Character, Node> getChild() {
             return child;
         }
 
@@ -148,16 +149,16 @@ private void buildSuffixAndOutputLinks() {
             }
         }
 
-        private ArrayList<ArrayList<Integer>> initializePositionByStringIndexValue() {
-            ArrayList<ArrayList<Integer>> positionByStringIndexValue = new ArrayList<>(patterns.length); // Stores positions where patterns are found in the text
+        private List<List<Integer>> initializePositionByStringIndexValue() {
+            List<List<Integer>> positionByStringIndexValue = new ArrayList<>(patterns.length); // Stores positions where patterns are found in the text
             for (int i = 0; i < patterns.length; i++) {
-                positionByStringIndexValue.add(new ArrayList<Integer>());
+                positionByStringIndexValue.add(new ArrayList<>());
             }
             return positionByStringIndexValue;
         }
 
         // Searches for patterns in the input text and records their positions
-        public ArrayList<ArrayList<Integer>> searchIn(final String text) {
+        public List<List<Integer>> searchIn(final String text) {
             var positionByStringIndexValue = initializePositionByStringIndexValue(); // Initialize a list to store positions of the current pattern
             Node parent = root; // Start searching from the root node
 
@@ -187,7 +188,7 @@ public ArrayList<ArrayList<Integer>> searchIn(final String text) {
 
         // by default positionByStringIndexValue contains end-points. This function converts those
         // endpoints to start points
-        private void setUpStartPoints(ArrayList<ArrayList<Integer>> positionByStringIndexValue) {
+        private void setUpStartPoints(List<List<Integer>> positionByStringIndexValue) {
             for (int i = 0; i < patterns.length; i++) {
                 for (int j = 0; j < positionByStringIndexValue.get(i).size(); j++) {
                     int endpoint = positionByStringIndexValue.get(i).get(j);
@@ -198,20 +199,15 @@ private void setUpStartPoints(ArrayList<ArrayList<Integer>> positionByStringInde
     }
 
     // Class to handle pattern position recording
-    private static class PatternPositionRecorder {
-        private ArrayList<ArrayList<Integer>> positionByStringIndexValue;
-
+    private record PatternPositionRecorder(List<List<Integer>> positionByStringIndexValue) {
         // Constructor to initialize the recorder with the position list
-        PatternPositionRecorder(final ArrayList<ArrayList<Integer>> positionByStringIndexValue) {
-            this.positionByStringIndexValue = positionByStringIndexValue;
-        }
 
         /**
          * Records positions for a pattern when it's found in the input text and follows
          * output links to record positions of other patterns.
          *
-         * @param parent The current node representing a character in the pattern trie.
-         * @param currentPosition      The current position in the input text.
+         * @param parent          The current node representing a character in the pattern trie.
+         * @param currentPosition The current position in the input text.
          */
         public void recordPatternPositions(final Node parent, final int currentPosition) {
             // Check if the current node represents the end of a pattern
@@ -229,19 +225,20 @@ public void recordPatternPositions(final Node parent, final int currentPosition)
             }
         }
     }
+
     // method to search for patterns in text
-    public static Map<String, ArrayList<Integer>> search(final String text, final String[] patterns) {
+    public static Map<String, List<Integer>> search(final String text, final String[] patterns) {
         final var trie = new Trie(patterns);
         final var positionByStringIndexValue = trie.searchIn(text);
         return convert(positionByStringIndexValue, patterns);
     }
 
     // method for converting results to a map
-    private static Map<String, ArrayList<Integer>> convert(final ArrayList<ArrayList<Integer>> positionByStringIndexValue, final String[] patterns) {
-        Map<String, ArrayList<Integer>> positionByString = new HashMap<>();
+    private static Map<String, List<Integer>> convert(final List<List<Integer>> positionByStringIndexValue, final String[] patterns) {
+        Map<String, List<Integer>> positionByString = new HashMap<>();
         for (int i = 0; i < patterns.length; i++) {
             String pattern = patterns[i];
-            ArrayList<Integer> positions = positionByStringIndexValue.get(i);
+            List<Integer> positions = positionByStringIndexValue.get(i);
             positionByString.put(pattern, new ArrayList<>(positions));
         }
         return positionByString;
diff --git a/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java b/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java
index caaca561143f..43137b358cf9 100644
--- a/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java
+++ b/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java
@@ -12,6 +12,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Map;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -42,7 +43,7 @@ void setUp() {
     @Test
     void testSearch() {
         // Define the expected results for each pattern
-        final var expected = Map.of("ACC", new ArrayList<>(Arrays.asList()), "ATC", new ArrayList<>(Arrays.asList(2)), "CAT", new ArrayList<>(Arrays.asList(1)), "GCG", new ArrayList<>(Arrays.asList()), "C", new ArrayList<>(Arrays.asList(1, 4)), "T", new ArrayList<>(Arrays.asList(3)));
+        final var expected = Map.of("ACC", new ArrayList<>(List.of()), "ATC", new ArrayList<>(List.of(2)), "CAT", new ArrayList<>(List.of(1)), "GCG", new ArrayList<>(List.of()), "C", new ArrayList<>(List.of(1, 4)), "T", new ArrayList<>(List.of(3)));
         assertEquals(expected, AhoCorasick.search(text, patterns));
     }
 
@@ -77,7 +78,7 @@ void testPatternNotFound() {
     void testPatternAtBeginning() {
         // Define patterns that start at the beginning of the text
         final var searchPatterns = new String[] {"GC", "GCA", "GCAT"};
-        final var expected = Map.of("GC", new ArrayList<Integer>(Arrays.asList(0)), "GCA", new ArrayList<Integer>(Arrays.asList(0)), "GCAT", new ArrayList<Integer>(Arrays.asList(0)));
+        final var expected = Map.of("GC", new ArrayList<>(List.of(0)), "GCA", new ArrayList<>(List.of(0)), "GCAT", new ArrayList<>(List.of(0)));
         assertEquals(expected, AhoCorasick.search(text, searchPatterns));
     }
 
@@ -89,7 +90,7 @@ void testPatternAtBeginning() {
     void testPatternAtEnd() {
         // Define patterns that end at the end of the text
         final var searchPatterns = new String[] {"CG", "TCG", "ATCG"};
-        final var expected = Map.of("CG", new ArrayList<Integer>(Arrays.asList(4)), "TCG", new ArrayList<Integer>(Arrays.asList(3)), "ATCG", new ArrayList<Integer>(Arrays.asList(2)));
+        final var expected = Map.of("CG", new ArrayList<>(List.of(4)), "TCG", new ArrayList<>(List.of(3)), "ATCG", new ArrayList<>(List.of(2)));
         assertEquals(expected, AhoCorasick.search(text, searchPatterns));
     }
 
@@ -102,7 +103,7 @@ void testPatternAtEnd() {
     void testMultipleOccurrencesOfPattern() {
         // Define patterns with multiple occurrences in the text
         final var searchPatterns = new String[] {"AT", "T"};
-        final var expected = Map.of("AT", new ArrayList<Integer>(Arrays.asList(2)), "T", new ArrayList<Integer>(Arrays.asList(3)));
+        final var expected = Map.of("AT", new ArrayList<>(List.of(2)), "T", new ArrayList<>(List.of(3)));
         assertEquals(expected, AhoCorasick.search(text, searchPatterns));
     }
 
@@ -114,7 +115,7 @@ void testMultipleOccurrencesOfPattern() {
     void testCaseInsensitiveSearch() {
         // Define patterns with different cases
         final var searchPatterns = new String[] {"gca", "aTc", "C"};
-        final var expected = Map.of("gca", new ArrayList<Integer>(), "aTc", new ArrayList<Integer>(), "C", new ArrayList<Integer>(Arrays.asList(1, 4)));
+        final var expected = Map.of("gca", new ArrayList<Integer>(), "aTc", new ArrayList<Integer>(), "C", new ArrayList<>(Arrays.asList(1, 4)));
         assertEquals(expected, AhoCorasick.search(text, searchPatterns));
     }
 }

From 74b05ef7c2bf34f2d1acda5f75fdbd8653e728c1 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 22 Aug 2024 11:37:52 +0200
Subject: [PATCH 0303/1338] refactor: fix typo in class name
 `LongestNonRepetitiveSubstring` (#5359)

---
 ...veSubstring.java => LongestNonRepetitiveSubstring.java} | 7 ++++---
 ...ingTest.java => LongestNonRepetitiveSubstringTest.java} | 6 +++---
 2 files changed, 7 insertions(+), 6 deletions(-)
 rename src/main/java/com/thealgorithms/strings/{LongestNonRepeativeSubstring.java => LongestNonRepetitiveSubstring.java} (87%)
 rename src/test/java/com/thealgorithms/strings/{LongestNonRepeativeSubstringTest.java => LongestNonRepetitiveSubstringTest.java} (50%)

diff --git a/src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java b/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java
similarity index 87%
rename from src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java
rename to src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java
index cc99a16facc3..c113162ff435 100644
--- a/src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java
+++ b/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java
@@ -1,16 +1,17 @@
 package com.thealgorithms.strings;
 
 import java.util.HashMap;
+import java.util.Map;
 
-final class LongestNonRepeativeSubstring {
-    private LongestNonRepeativeSubstring() {
+final class LongestNonRepetitiveSubstring {
+    private LongestNonRepetitiveSubstring() {
     }
 
     public static int lengthOfLongestSubstring(String s) {
         int max = 0;
         int start = 0;
         int i = 0;
-        HashMap<Character, Integer> map = new HashMap<>();
+        Map<Character, Integer> map = new HashMap<>();
 
         while (i < s.length()) {
             char temp = s.charAt(i);
diff --git a/src/test/java/com/thealgorithms/strings/LongestNonRepeativeSubstringTest.java b/src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java
similarity index 50%
rename from src/test/java/com/thealgorithms/strings/LongestNonRepeativeSubstringTest.java
rename to src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java
index 4bd5ac996719..c6fd8c59c53e 100644
--- a/src/test/java/com/thealgorithms/strings/LongestNonRepeativeSubstringTest.java
+++ b/src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java
@@ -3,13 +3,13 @@
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
-public class LongestNonRepeativeSubstringTest {
+public class LongestNonRepetitiveSubstringTest {
 
     @Test
     public void palindrome() {
         String input1 = "HelloWorld";
         String input2 = "javaIsAProgrammingLanguage";
-        Assertions.assertEquals(LongestNonRepeativeSubstring.lengthOfLongestSubstring(input1), 5);
-        Assertions.assertEquals(LongestNonRepeativeSubstring.lengthOfLongestSubstring(input2), 9);
+        Assertions.assertEquals(LongestNonRepetitiveSubstring.lengthOfLongestSubstring(input1), 5);
+        Assertions.assertEquals(LongestNonRepetitiveSubstring.lengthOfLongestSubstring(input2), 9);
     }
 }

From 56f97c48acc5484b0148e0cbed0a786835feabaa Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 23 Aug 2024 00:42:44 +0200
Subject: [PATCH 0304/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-checkstyle-plugin from 3.4.0 to 3.5.0 (#5368)

Chore(deps): bump org.apache.maven.plugins:maven-checkstyle-plugin

Bumps [org.apache.maven.plugins:maven-checkstyle-plugin](https://github.com/apache/maven-checkstyle-plugin) from 3.4.0 to 3.5.0.
- [Commits](https://github.com/apache/maven-checkstyle-plugin/compare/maven-checkstyle-plugin-3.4.0...maven-checkstyle-plugin-3.5.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-checkstyle-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index a46e469c40e3..5854aff4ff1e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -107,7 +107,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-checkstyle-plugin</artifactId>
-                <version>3.4.0</version>
+                <version>3.5.0</version>
                 <configuration>
                     <configLocation>checkstyle.xml</configLocation>
                     <consoleOutput>true</consoleOutput>

From fb55552ebbcf452407644560800385175d4888e1 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 23 Aug 2024 09:58:08 +0200
Subject: [PATCH 0305/1338] refactor: fix typo (#5363)

---
 src/main/java/com/thealgorithms/maths/TwinPrime.java           | 2 +-
 src/main/java/com/thealgorithms/strings/StringCompression.java | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/TwinPrime.java b/src/main/java/com/thealgorithms/maths/TwinPrime.java
index 81731376b37a..ef8de0d1018e 100644
--- a/src/main/java/com/thealgorithms/maths/TwinPrime.java
+++ b/src/main/java/com/thealgorithms/maths/TwinPrime.java
@@ -16,7 +16,7 @@ private TwinPrime() {
     /**
      * This method returns twin prime of the integer value passed as argument
      *
-     * @param input_number Integer value of which twin prime is to be found
+     * @param inputNumber Integer value of which twin prime is to be found
      * @return (number + 2) if number and (number + 2) are prime, -1 otherwise
      */
     static int getTwinPrime(int inputNumber) {
diff --git a/src/main/java/com/thealgorithms/strings/StringCompression.java b/src/main/java/com/thealgorithms/strings/StringCompression.java
index 131bd4165493..ddbee4c4f91a 100644
--- a/src/main/java/com/thealgorithms/strings/StringCompression.java
+++ b/src/main/java/com/thealgorithms/strings/StringCompression.java
@@ -10,7 +10,7 @@ private StringCompression() {
     /**
      * Returns the compressed or encoded string
      *
-     * @param ch character array that contains the group of characters to be encoded
+     * @param input character array that contains the group of characters to be encoded
      * @return the compressed character array as string
      */
     public static String compress(String input) {

From 0301ecf1cb9582d7146b3e2ecd1fec163f9bd847 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 23 Aug 2024 10:59:20 +0200
Subject: [PATCH 0306/1338] refactor: `Pow` (#5364)

---
 .../java/com/thealgorithms/maths/Pow.java     | 32 ++++++++++-------
 .../java/com/thealgorithms/maths/PowTest.java | 36 +++++++++++++++++++
 2 files changed, 55 insertions(+), 13 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/PowTest.java

diff --git a/src/main/java/com/thealgorithms/maths/Pow.java b/src/main/java/com/thealgorithms/maths/Pow.java
index 3f362fe88d30..377b37ac4569 100644
--- a/src/main/java/com/thealgorithms/maths/Pow.java
+++ b/src/main/java/com/thealgorithms/maths/Pow.java
@@ -1,26 +1,32 @@
 package com.thealgorithms.maths;
 
-// POWER (exponentials) Examples (a^b)
+/**
+ * A utility class for computing exponentiation (power) of integers.
+ * <p>
+ * This class provides a method to calculate the value of a base raised to a given exponent using a simple iterative approach.
+ * For example, given a base {@code a} and an exponent {@code b}, the class computes {@code a}<sup>{@code b}</sup>.
+ * </p>
+ */
 public final class Pow {
     private Pow() {
     }
 
-    public static void main(String[] args) {
-        assert pow(2, 0) == Math.pow(2, 0); // == 1
-        assert pow(0, 2) == Math.pow(0, 2); // == 0
-        assert pow(2, 10) == Math.pow(2, 10); // == 1024
-        assert pow(10, 2) == Math.pow(10, 2); // == 100
-    }
-
     /**
-     * Returns the value of the first argument raised to the power of the second
-     * argument
+     * Computes the value of the base raised to the power of the exponent.
+     * <p>
+     * The method calculates {@code a}<sup>{@code b}</sup> by iteratively multiplying the base {@code a} with itself {@code b} times.
+     * If the exponent {@code b} is negative, an {@code IllegalArgumentException} is thrown.
+     * </p>
      *
-     * @param a the base.
-     * @param b the exponent.
-     * @return the value {@code a}<sup>{@code b}</sup>.
+     * @param a the base of the exponentiation. Must be a non-negative integer.
+     * @param b the exponent to which the base {@code a} is raised. Must be a non-negative integer.
+     * @return the result of {@code a}<sup>{@code b}</sup> as a {@code long}.
+     * @throws IllegalArgumentException if {@code b} is negative.
      */
     public static long pow(int a, int b) {
+        if (b < 0) {
+            throw new IllegalArgumentException("Exponent must be non-negative.");
+        }
         long result = 1;
         for (int i = 1; i <= b; i++) {
             result *= a;
diff --git a/src/test/java/com/thealgorithms/maths/PowTest.java b/src/test/java/com/thealgorithms/maths/PowTest.java
new file mode 100644
index 000000000000..4309b0f10ed5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/PowTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class PowTest {
+    @ParameterizedTest
+    @CsvSource({"2, 0, 1", "0, 2, 0", "2, 10, 1024", "10, 2, 100", "5, 3, 125", "3, 4, 81"})
+    void testPow(int base, int exponent, long expected) {
+        assertEquals(expected, Pow.pow(base, exponent), "Failed for base: " + base + " and exponent: " + exponent);
+    }
+
+    @Test
+    void testPowThrowsExceptionForNegativeExponent() {
+        assertThrows(IllegalArgumentException.class, () -> Pow.pow(2, -1));
+    }
+
+    @Test
+    void testPowHandlesLargeNumbers() {
+        assertEquals(1048576, Pow.pow(2, 20));
+    }
+
+    @Test
+    void testPowHandlesZeroBase() {
+        assertEquals(0, Pow.pow(0, 5));
+    }
+
+    @Test
+    void testPowHandlesOneBase() {
+        assertEquals(1, Pow.pow(1, 100));
+    }
+}

From d7b60be7d1e1f9805fe54d54d8d4fb0ab0efde98 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 23 Aug 2024 11:33:41 +0200
Subject: [PATCH 0307/1338] refactor: `PermuteString` (#5362)

---
 .../thealgorithms/strings/PermuteString.java  | 108 ++++++++++++------
 .../strings/PermuteStringTest.java            |  29 +++++
 2 files changed, 102 insertions(+), 35 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/strings/PermuteStringTest.java

diff --git a/src/main/java/com/thealgorithms/strings/PermuteString.java b/src/main/java/com/thealgorithms/strings/PermuteString.java
index f263292eb7bd..124bdb6287b4 100644
--- a/src/main/java/com/thealgorithms/strings/PermuteString.java
+++ b/src/main/java/com/thealgorithms/strings/PermuteString.java
@@ -1,51 +1,89 @@
 package com.thealgorithms.strings;
 
-/*
-Backtracking algorithm used in the program:-
+import java.util.HashSet;
+import java.util.Set;
 
->>Fix a character in the first position and swap the rest of the character with the first character.
-  Like in ABC, in the first iteration three strings are formed: ABC, BAC, and CBA by swapping A with
-  A, B and C respectively.
->>Repeat step 1 for the rest of the characters like fixing second character B and so on.
->>Now swap again to go back to the previous position. E.g., from ABC, we formed ABC by fixing B
-again, and we backtrack to the previous position and swap B with C. So, now we got ABC and ACB.
->>Repeat these steps for BAC and CBA, to get all the permutations.
+/**
+ * This class provides methods for generating all permutations of a given string using a backtracking algorithm.
+ * <p>
+ * The algorithm works as follows:
+ * <ol>
+ *     <li>Fix a character in the current position and swap it with each of the remaining characters.
+ *         For example, for the string "ABC":
+ *         <ul>
+ *             <li>Fix 'A' at the first position: permutations are "ABC", "BAC", "CBA" (obtained by swapping 'A' with 'B' and 'C' respectively).</li>
+ *         </ul>
+ *     </li>
+ *     <li>Repeat the process for the next character.
+ *         For instance, after fixing 'B' in the second position:
+ *         <ul>
+ *             <li>For "BAC", the permutations include "BAC" and "BCA" (after swapping 'A' and 'C').</li>
+ *         </ul>
+ *     </li>
+ *     <li>After generating permutations for the current position, backtrack by swapping the characters back to their original positions to restore the state.
+ *         For example, after generating permutations for "ABC", swap back to restore "BAC" and continue with further permutations.</li>
+ *     <li>Repeat the process for all characters to get all possible permutations.</li>
+ * </ol>
+ * </p>
  */
 public final class PermuteString {
     private PermuteString() {
     }
 
-    // Function for swapping the characters at position I with character at position j
-    public static String swapString(String a, int i, int j) {
-        char[] b = a.toCharArray();
-        char ch;
-        ch = b[i];
-        b[i] = b[j];
-        b[j] = ch;
-        return String.valueOf(b);
+    /**
+     * Generates all possible permutations of the given string.
+     *
+     * <p>This method returns a set containing all unique permutations of the input string. It leverages
+     * a recursive helper method to generate these permutations.
+     *
+     * @param str The input string for which permutations are to be generated.
+     *            If the string is null or empty, the result will be an empty set.
+     * @return A {@link Set} of strings containing all unique permutations of the input string.
+     *         If the input string has duplicate characters, the set will ensure that only unique permutations
+     *         are returned.
+     */
+    public static Set<String> getPermutations(String str) {
+        Set<String> permutations = new HashSet<>();
+        generatePermutations(str, 0, str.length(), permutations);
+        return permutations;
     }
 
-    public static void main(String[] args) {
-        String str = "ABC";
-        int len = str.length();
-        System.out.println("All the permutations of the string are: ");
-        generatePermutation(str, 0, len);
-    }
-
-    // Function for generating different permutations of the string
-    public static void generatePermutation(String str, int start, int end) {
-        // Prints the permutations
+    /**
+     * Generates all permutations of the given string and collects them into a set.
+     *
+     * @param str the string to permute
+     * @param start the starting index for the current permutation
+     * @param end the end index (length of the string)
+     * @param permutations the set to collect all unique permutations
+     */
+    private static void generatePermutations(String str, int start, int end, Set<String> permutations) {
         if (start == end - 1) {
-            System.out.println(str);
+            permutations.add(str);
         } else {
-            for (int i = start; i < end; i++) {
-                // Swapping the string by fixing a character
-                str = swapString(str, start, i);
-                // Recursively calling function generatePermutation() for rest of the characters
-                generatePermutation(str, start + 1, end);
-                // Backtracking and swapping the characters again.
-                str = swapString(str, start, i);
+            for (int currentIndex = start; currentIndex < end; currentIndex++) {
+                // Swap the current character with the character at the start index
+                str = swapCharacters(str, start, currentIndex);
+                // Recursively generate permutations for the remaining characters
+                generatePermutations(str, start + 1, end, permutations);
+                // Backtrack: swap the characters back to their original positions
+                str = swapCharacters(str, start, currentIndex);
             }
         }
     }
+
+    /**
+     * Swaps the characters at the specified positions in the given string.
+     *
+     * @param str the string in which characters will be swapped
+     * @param i the position of the first character to swap
+     * @param j the position of the second character to swap
+     * @return a new string with the characters at positions i and j swapped
+     */
+    private static String swapCharacters(String str, int i, int j) {
+        char[] chars = str.toCharArray();
+        char temp = chars[i];
+        chars[i] = chars[j];
+        chars[j] = temp;
+        return new String(chars);
+    }
 }
diff --git a/src/test/java/com/thealgorithms/strings/PermuteStringTest.java b/src/test/java/com/thealgorithms/strings/PermuteStringTest.java
new file mode 100644
index 000000000000..c726874f4cec
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/PermuteStringTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Set;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class PermuteStringTest {
+
+    private static Stream<TestData> provideTestCases() {
+        return Stream.of(new TestData("ABC", Set.of("ABC", "ACB", "BAC", "BCA", "CAB", "CBA")), new TestData("AB", Set.of("AB", "BA")), new TestData("A", Set.of("A")), new TestData("AA", Set.of("AA")), new TestData("123", Set.of("123", "132", "213", "231", "312", "321")),
+            new TestData("aA", Set.of("aA", "Aa")), new TestData("AaB", Set.of("AaB", "ABa", "aAB", "aBA", "BAa", "BaA")), new TestData("!@", Set.of("!@", "@!")), new TestData("!a@", Set.of("!a@", "!@a", "a!@", "a@!", "@!a", "@a!")),
+            new TestData("ABCD", Set.of("ABCD", "ABDC", "ACBD", "ACDB", "ADBC", "ADCB", "BACD", "BADC", "BCAD", "BCDA", "BDAC", "BDCA", "CABD", "CADB", "CBAD", "CBDA", "CDAB", "CDBA", "DABC", "DACB", "DBAC", "DBCA", "DCAB", "DCBA")),
+            new TestData("A B", Set.of("A B", "AB ", " AB", " BA", "BA ", "B A")),
+            new TestData("abcd", Set.of("abcd", "abdc", "acbd", "acdb", "adbc", "adcb", "bacd", "badc", "bcad", "bcda", "bdac", "bdca", "cabd", "cadb", "cbad", "cbda", "cdab", "cdba", "dabc", "dacb", "dbac", "dbca", "dcab", "dcba")));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testPermutations(TestData testData) {
+        Set<String> actualPermutations = PermuteString.getPermutations(testData.input);
+        assertEquals(testData.expected, actualPermutations, "The permutations of '" + testData.input + "' are not correct.");
+    }
+
+    record TestData(String input, Set<String> expected) {
+    }
+}

From 844aeaf70145167d4ee6cdbf87c04ee14ff8c71a Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 23 Aug 2024 13:23:16 +0200
Subject: [PATCH 0308/1338] refactor: `LFUCache` (#5369)

---
 .../datastructures/caches/LFUCache.java       | 53 +++++++++----------
 1 file changed, 26 insertions(+), 27 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java b/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
index 6e37b4a7109d..a5b83af14551 100644
--- a/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
+++ b/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
@@ -10,8 +10,7 @@
 public class LFUCache<K, V> {
 
     private class Node {
-
-        private K key;
+        private final K key;
         private V value;
         private int frequency;
         private Node previous;
@@ -26,67 +25,67 @@ private class Node {
 
     private Node head;
     private Node tail;
-    private Map<K, Node> map = null;
-    private Integer capacity;
+    private final Map<K, Node> cache;
+    private final int capacity;
     private static final int DEFAULT_CAPACITY = 100;
 
     public LFUCache() {
-        this.capacity = DEFAULT_CAPACITY;
+        this(DEFAULT_CAPACITY);
     }
 
-    public LFUCache(Integer capacity) {
+    public LFUCache(int capacity) {
+        if (capacity <= 0) {
+            throw new IllegalArgumentException("Capacity must be greater than zero.");
+        }
         this.capacity = capacity;
-        this.map = new HashMap<>();
+        this.cache = new HashMap<>();
     }
 
     /**
-     * This method returns value present in the cache corresponding to the key passed as parameter
+     * Retrieves the value for the given key from the cache. Increases the frequency of the node.
      *
-     * @param <K> key for which value is to be retrieved
-     * @returns <V> object corresponding to the key passed as parameter, returns null if <K> key is
-     *     not present in the cache
+     * @param key The key to look up.
+     * @return The value associated with the key, or null if the key is not present.
      */
     public V get(K key) {
-        if (this.map.get(key) == null) {
+        Node node = cache.get(key);
+        if (node == null) {
             return null;
         }
-
-        Node node = map.get(key);
         removeNode(node);
         node.frequency += 1;
         addNodeWithUpdatedFrequency(node);
-
         return node.value;
     }
 
     /**
-     * This method stores <K> key and <V> value in the cache
+     * Adds or updates a key-value pair in the cache. If the cache is full, the least frequently used item is evicted.
      *
-     * @param <K> key which is to be stored in the cache
-     * @param <V> value which is to be stored in the cache
+     * @param key   The key to insert or update.
+     * @param value The value to insert or update.
      */
     public void put(K key, V value) {
-        if (map.containsKey(key)) {
-            Node node = map.get(key);
+        if (cache.containsKey(key)) {
+            Node node = cache.get(key);
             node.value = value;
             node.frequency += 1;
             removeNode(node);
             addNodeWithUpdatedFrequency(node);
         } else {
-            if (map.size() >= capacity) {
-                map.remove(this.head.key);
+            if (cache.size() >= capacity) {
+                cache.remove(this.head.key);
                 removeNode(head);
             }
             Node node = new Node(key, value, 1);
             addNodeWithUpdatedFrequency(node);
-            map.put(key, node);
+            cache.put(key, node);
         }
     }
 
     /**
-     * This method stores the node in the cache with updated frequency
+     * Adds a node to the linked list in the correct position based on its frequency.
      *
-     * @param Node node which is to be updated in the cache
+     * @param node The node to add.
      */
     private void addNodeWithUpdatedFrequency(Node node) {
         if (tail != null && head != null) {
@@ -123,9 +122,9 @@ private void addNodeWithUpdatedFrequency(Node node) {
     }
 
     /**
-     * This method removes node from the cache
+     * Removes a node from the linked list.
      *
-     * @param Node node which is to be removed in the cache
+     * @param node The node to remove.
      */
     private void removeNode(Node node) {
         if (node.previous != null) {

From a6fcbf585fc6c1e6f9452b483245525c8b4ed1fb Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 23 Aug 2024 13:28:47 +0200
Subject: [PATCH 0309/1338] test: `LinkedListStackTest` (#5366)

---
 .../stacks/LinkedListStackTest.java           | 71 +++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java

diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java
new file mode 100644
index 000000000000..8c3689a79729
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java
@@ -0,0 +1,71 @@
+package com.thealgorithms.datastructures.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.NoSuchElementException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class LinkedListStackTest {
+
+    private LinkedListStack stack;
+
+    @BeforeEach
+    public void setUp() {
+        stack = new LinkedListStack();
+    }
+
+    @Test
+    public void testPushAndPeek() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+
+        assertEquals(3, stack.peek());
+        assertEquals(3, stack.getSize());
+    }
+
+    @Test
+    public void testPop() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+
+        assertEquals(3, stack.pop());
+        assertEquals(2, stack.pop());
+        assertEquals(1, stack.pop());
+        assertTrue(stack.isEmpty());
+    }
+
+    @Test
+    public void testPopEmptyStack() {
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, () -> stack.pop());
+    }
+
+    @Test
+    public void testPeekEmptyStack() {
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, () -> stack.peek());
+    }
+
+    @Test
+    public void testIsEmpty() {
+        assertTrue(stack.isEmpty());
+
+        stack.push(1);
+        assertFalse(stack.isEmpty());
+
+        stack.pop();
+        assertTrue(stack.isEmpty());
+    }
+
+    @Test
+    public void testToString() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+
+        assertEquals("3->2->1", stack.toString());
+    }
+}

From 34089774f3ec45d1e64418ab4abe4b87530a6054 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 23 Aug 2024 13:37:44 +0200
Subject: [PATCH 0310/1338] test: refactor `PalindromeTest` (#5365)

---
 .../thealgorithms/strings/PalindromeTest.java | 24 +++++++++----------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/test/java/com/thealgorithms/strings/PalindromeTest.java b/src/test/java/com/thealgorithms/strings/PalindromeTest.java
index f07736c37890..d839e381c6dd 100644
--- a/src/test/java/com/thealgorithms/strings/PalindromeTest.java
+++ b/src/test/java/com/thealgorithms/strings/PalindromeTest.java
@@ -1,21 +1,21 @@
 package com.thealgorithms.strings;
 
+import java.util.stream.Stream;
 import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class PalindromeTest {
+    private static Stream<TestData> provideTestCases() {
+        return Stream.of(new TestData(null, true), new TestData("", true), new TestData("aba", true), new TestData("123321", true), new TestData("kayak", true), new TestData("abb", false), new TestData("abc", false), new TestData("abc123", false), new TestData("kayaks", false));
+    }
 
-    @Test
-    public void palindrome() {
-
-        String[] palindromes = {null, "", "aba", "123321", "kayak"};
-        for (String s : palindromes) {
-            Assertions.assertTrue(Palindrome.isPalindrome(s) && Palindrome.isPalindromeRecursion(s) && Palindrome.isPalindromeTwoPointer(s));
-        }
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testPalindrome(TestData testData) {
+        Assertions.assertEquals(testData.expected, Palindrome.isPalindrome(testData.input) && Palindrome.isPalindromeRecursion(testData.input) && Palindrome.isPalindromeTwoPointer(testData.input));
+    }
 
-        String[] notPalindromes = {"abb", "abc", "abc123", "kayaks"};
-        for (String s : notPalindromes) {
-            Assertions.assertFalse(Palindrome.isPalindrome(s) || Palindrome.isPalindromeRecursion(s) || Palindrome.isPalindromeTwoPointer(s));
-        }
+    private record TestData(String input, boolean expected) {
     }
 }

From ce4eb55e0e7c5216e2cba53217627f6bbe8b5083 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 23 Aug 2024 14:55:13 +0200
Subject: [PATCH 0311/1338] refactor: `FloydTriangle` (#5367)

---
 .../thealgorithms/others/FloydTriangle.java   | 28 +++++++----
 .../others/FloydTriangleTest.java             | 46 +++++++++++++++++++
 2 files changed, 64 insertions(+), 10 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/FloydTriangleTest.java

diff --git a/src/main/java/com/thealgorithms/others/FloydTriangle.java b/src/main/java/com/thealgorithms/others/FloydTriangle.java
index fbeaec339248..dff48443fc25 100644
--- a/src/main/java/com/thealgorithms/others/FloydTriangle.java
+++ b/src/main/java/com/thealgorithms/others/FloydTriangle.java
@@ -1,22 +1,30 @@
 package com.thealgorithms.others;
 
-import java.util.Scanner;
+import java.util.ArrayList;
+import java.util.List;
 
 final class FloydTriangle {
     private FloydTriangle() {
     }
 
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        System.out.println("Enter the number of rows which you want in your Floyd Triangle: ");
-        int r = sc.nextInt();
-        int n = 0;
-        sc.close();
-        for (int i = 0; i < r; i++) {
+    /**
+     * Generates a Floyd Triangle with the specified number of rows.
+     *
+     * @param rows The number of rows in the triangle.
+     * @return A List representing the Floyd Triangle.
+     */
+    public static List<List<Integer>> generateFloydTriangle(int rows) {
+        List<List<Integer>> triangle = new ArrayList<>();
+        int number = 1;
+
+        for (int i = 0; i < rows; i++) {
+            List<Integer> row = new ArrayList<>();
             for (int j = 0; j <= i; j++) {
-                System.out.print(++n + " ");
+                row.add(number++);
             }
-            System.out.println();
+            triangle.add(row);
         }
+
+        return triangle;
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/FloydTriangleTest.java b/src/test/java/com/thealgorithms/others/FloydTriangleTest.java
new file mode 100644
index 000000000000..afa280c09838
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/FloydTriangleTest.java
@@ -0,0 +1,46 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class FloydTriangleTest {
+
+    @Test
+    public void testGenerateFloydTriangleWithValidInput() {
+        List<List<Integer>> expectedOutput = Arrays.asList(Arrays.asList(1), Arrays.asList(2, 3), Arrays.asList(4, 5, 6));
+        assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(3));
+    }
+
+    @Test
+    public void testGenerateFloydTriangleWithOneRow() {
+        List<List<Integer>> expectedOutput = Arrays.asList(Arrays.asList(1));
+        assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(1));
+    }
+
+    @Test
+    public void testGenerateFloydTriangleWithZeroRows() {
+        List<List<Integer>> expectedOutput = Arrays.asList();
+        assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(0));
+    }
+
+    @Test
+    public void testGenerateFloydTriangleWithNegativeRows() {
+        List<List<Integer>> expectedOutput = Arrays.asList();
+        assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(-3));
+    }
+
+    @Test
+    public void testGenerateFloydTriangleWithMultipleRows() {
+        List<List<Integer>> expectedOutput = Arrays.asList(Arrays.asList(1), Arrays.asList(2, 3), Arrays.asList(4, 5, 6), Arrays.asList(7, 8, 9, 10), Arrays.asList(11, 12, 13, 14, 15));
+        assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(5));
+    }
+
+    @Test
+    public void testGenerateFloydTriangleWithMoreMultipleRows() {
+        List<List<Integer>> expectedOutput = Arrays.asList(Arrays.asList(1), Arrays.asList(2, 3), Arrays.asList(4, 5, 6), Arrays.asList(7, 8, 9, 10), Arrays.asList(11, 12, 13, 14, 15), Arrays.asList(16, 17, 18, 19, 20, 21), Arrays.asList(22, 23, 24, 25, 26, 27, 28));
+        assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(7));
+    }
+}

From 44d7cbbaf414253413dfc90164b1c55f580bdb4c Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 24 Aug 2024 10:27:39 +0200
Subject: [PATCH 0312/1338] test: `NQueensTest` (#5378)

---
 .../thealgorithms/backtracking/NQueens.java   | 11 ++---
 .../backtracking/NQueensTest.java             | 48 +++++++++++++++++++
 2 files changed, 52 insertions(+), 7 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/backtracking/NQueensTest.java

diff --git a/src/main/java/com/thealgorithms/backtracking/NQueens.java b/src/main/java/com/thealgorithms/backtracking/NQueens.java
index e21a8bb7174c..1a8e453e34cb 100644
--- a/src/main/java/com/thealgorithms/backtracking/NQueens.java
+++ b/src/main/java/com/thealgorithms/backtracking/NQueens.java
@@ -36,13 +36,10 @@ public final class NQueens {
     private NQueens() {
     }
 
-    public static void main(String[] args) {
-        placeQueens(1);
-        placeQueens(2);
-        placeQueens(3);
-        placeQueens(4);
-        placeQueens(5);
-        placeQueens(6);
+    public static List<List<String>> getNQueensArrangements(int queens) {
+        List<List<String>> arrangements = new ArrayList<>();
+        getSolution(queens, arrangements, new int[queens], 0);
+        return arrangements;
     }
 
     public static void placeQueens(final int queens) {
diff --git a/src/test/java/com/thealgorithms/backtracking/NQueensTest.java b/src/test/java/com/thealgorithms/backtracking/NQueensTest.java
new file mode 100644
index 000000000000..977e3dfae2ce
--- /dev/null
+++ b/src/test/java/com/thealgorithms/backtracking/NQueensTest.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.backtracking;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class NQueensTest {
+
+    @Test
+    public void testNQueens1() {
+        List<List<String>> expected = Arrays.asList(Arrays.asList("Q"));
+        assertEquals(expected, NQueens.getNQueensArrangements(1));
+    }
+
+    @Test
+    public void testNQueens2() {
+        List<List<String>> expected = new ArrayList<>(); // No solution exists
+        assertEquals(expected, NQueens.getNQueensArrangements(2));
+    }
+
+    @Test
+    public void testNQueens3() {
+        List<List<String>> expected = new ArrayList<>(); // No solution exists
+        assertEquals(expected, NQueens.getNQueensArrangements(3));
+    }
+
+    @Test
+    public void testNQueens4() {
+        List<List<String>> expected = Arrays.asList(Arrays.asList(".Q..", "...Q", "Q...", "..Q."), Arrays.asList("..Q.", "Q...", "...Q", ".Q.."));
+        assertEquals(expected, NQueens.getNQueensArrangements(4));
+    }
+
+    @Test
+    public void testNQueens5() {
+        // Only the number of solutions is tested for larger N due to the complexity of checking each board configuration
+        List<List<String>> result = NQueens.getNQueensArrangements(5);
+        assertEquals(10, result.size()); // 5x5 board has 10 solutions
+    }
+
+    @Test
+    public void testNQueens6() {
+        List<List<String>> result = NQueens.getNQueensArrangements(6);
+        assertEquals(4, result.size()); // 6x6 board has 4 solutions
+    }
+}

From aefc8fd4b821ca9ca04c499ffbb8e23c41c3efc4 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 24 Aug 2024 10:32:50 +0200
Subject: [PATCH 0313/1338] refactor: `HexToOct` (#5377)

---
 .../thealgorithms/conversions/HexToOct.java   | 81 ++++++++-----------
 .../conversions/HexToOctTest.java             | 25 +++++-
 2 files changed, 56 insertions(+), 50 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/HexToOct.java b/src/main/java/com/thealgorithms/conversions/HexToOct.java
index 97a8be16b2e0..d3a672d37424 100644
--- a/src/main/java/com/thealgorithms/conversions/HexToOct.java
+++ b/src/main/java/com/thealgorithms/conversions/HexToOct.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.conversions;
 
-import java.util.Scanner;
-
 /**
  * Converts any Hexadecimal Number to Octal
  *
@@ -12,64 +10,53 @@ private HexToOct() {
     }
 
     /**
-     * This method converts a Hexadecimal number to a decimal number
+     * Converts a Hexadecimal number to a Decimal number.
      *
-     * @param s The Hexadecimal Number
-     * @return The Decimal number
+     * @param hex The Hexadecimal number as a String.
+     * @return The Decimal equivalent as an integer.
      */
-    public static int hex2decimal(String s) {
-        String str = "0123456789ABCDEF";
-        s = s.toUpperCase();
-        int val = 0;
-        for (int i = 0; i < s.length(); i++) {
-            char a = s.charAt(i);
-            int n = str.indexOf(a);
-            val = 16 * val + n;
+    public static int hexToDecimal(String hex) {
+        String hexDigits = "0123456789ABCDEF";
+        hex = hex.toUpperCase();
+        int decimalValue = 0;
+
+        for (int i = 0; i < hex.length(); i++) {
+            char hexChar = hex.charAt(i);
+            int digitValue = hexDigits.indexOf(hexChar);
+            decimalValue = 16 * decimalValue + digitValue;
         }
-        return val;
+
+        return decimalValue;
     }
 
     /**
-     * This method converts a Decimal number to a octal number
+     * Converts a Decimal number to an Octal number.
      *
-     * @param q The Decimal Number
-     * @return The Octal number
+     * @param decimal The Decimal number as an integer.
+     * @return The Octal equivalent as an integer.
      */
-    public static int decimal2octal(int q) {
-        int now;
-        int i = 1;
-        int octnum = 0;
-        while (q > 0) {
-            now = q % 8;
-            octnum = (now * (int) (Math.pow(10, i))) + octnum;
-            q /= 8;
-            i++;
+    public static int decimalToOctal(int decimal) {
+        int octalValue = 0;
+        int placeValue = 1;
+
+        while (decimal > 0) {
+            int remainder = decimal % 8;
+            octalValue += remainder * placeValue;
+            decimal /= 8;
+            placeValue *= 10;
         }
-        octnum /= 10;
-        return octnum;
+
+        return octalValue;
     }
 
     /**
-     * Main method that gets the hex input from user and converts it into octal.
+     * Converts a Hexadecimal number to an Octal number.
      *
-     * @param args arguments
+     * @param hex The Hexadecimal number as a String.
+     * @return The Octal equivalent as an integer.
      */
-    public static void main(String[] args) {
-        String hexadecnum;
-        int decnum;
-        int octalnum;
-        Scanner scan = new Scanner(System.in);
-
-        System.out.print("Enter Hexadecimal Number : ");
-        hexadecnum = scan.nextLine();
-
-        // first convert hexadecimal to decimal
-        decnum = hex2decimal(hexadecnum); // Pass the string to the hex2decimal function and get the decimal form in
-        // variable decnum
-
-        // convert decimal to octal
-        octalnum = decimal2octal(decnum);
-        System.out.println("Number in octal: " + octalnum);
-        scan.close();
+    public static int hexToOctal(String hex) {
+        int decimalValue = hexToDecimal(hex);
+        return decimalToOctal(decimalValue);
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/HexToOctTest.java b/src/test/java/com/thealgorithms/conversions/HexToOctTest.java
index 5924aa31854b..b3f94b19b6e6 100644
--- a/src/test/java/com/thealgorithms/conversions/HexToOctTest.java
+++ b/src/test/java/com/thealgorithms/conversions/HexToOctTest.java
@@ -5,10 +5,29 @@
 import org.junit.jupiter.api.Test;
 
 public class HexToOctTest {
+    @Test
+    public void testHexToDecimal() {
+        assertEquals(255, HexToOct.hexToDecimal("FF"));
+        assertEquals(16, HexToOct.hexToDecimal("10"));
+        assertEquals(0, HexToOct.hexToDecimal("0"));
+        assertEquals(4095, HexToOct.hexToDecimal("FFF"));
+    }
+
+    @Test
+    public void testDecimalToOctal() {
+        assertEquals(110, HexToOct.decimalToOctal(HexToOct.hexToDecimal("48")));
+        assertEquals(255, HexToOct.decimalToOctal(HexToOct.hexToDecimal("AD")));
+        assertEquals(377, HexToOct.decimalToOctal(255));
+        assertEquals(20, HexToOct.decimalToOctal(16));
+        assertEquals(0, HexToOct.decimalToOctal(0));
+        assertEquals(7777, HexToOct.decimalToOctal(4095));
+    }
 
     @Test
-    public void testHexToOct() {
-        assertEquals(110, HexToOct.decimal2octal(HexToOct.hex2decimal("48")));
-        assertEquals(255, HexToOct.decimal2octal(HexToOct.hex2decimal("AD")));
+    public void testHexToOctal() {
+        assertEquals(377, HexToOct.hexToOctal("FF"));
+        assertEquals(20, HexToOct.hexToOctal("10"));
+        assertEquals(0, HexToOct.hexToOctal("0"));
+        assertEquals(7777, HexToOct.hexToOctal("FFF"));
     }
 }

From 84fb717509a5831979671f6e50204f900a1d9fb6 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 24 Aug 2024 10:38:16 +0200
Subject: [PATCH 0314/1338] test: `DeterminantOfMatrix` (#5376)

---
 .../maths/DeterminantOfMatrix.java            | 28 +++--------
 .../maths/DeterminantOfMatrixTest.java        | 50 +++++++++++++++++++
 2 files changed, 57 insertions(+), 21 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/DeterminantOfMatrixTest.java

diff --git a/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java b/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
index a2a327117700..b652d4903da8 100644
--- a/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
+++ b/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.maths;
 
-import java.util.Scanner;
-
 /*
  * @author Ojasva Jain
  * Determinant of a Matrix Wikipedia link: https://en.wikipedia.org/wiki/Determinant
@@ -10,8 +8,13 @@ public final class DeterminantOfMatrix {
     private DeterminantOfMatrix() {
     }
 
-    // Determinant calculator
-    //@return determinant of the input matrix
+    /**
+     * Calculates the determinant of a given matrix.
+     *
+     * @param a the input matrix
+     * @param n the size of the matrix
+     * @return the determinant of the matrix
+     */
     static int determinant(int[][] a, int n) {
         int det = 0;
         int sign = 1;
@@ -41,21 +44,4 @@ static int determinant(int[][] a, int n) {
         }
         return det;
     }
-
-    // Driver Method
-    public static void main(String[] args) {
-        Scanner in = new Scanner(System.in);
-        // Input Matrix
-        System.out.println("Enter matrix size (Square matrix only)");
-        int n = in.nextInt();
-        System.out.println("Enter matrix");
-        int[][] a = new int[n][n];
-        for (int i = 0; i < n; i++) {
-            for (int j = 0; j < n; j++) {
-                a[i][j] = in.nextInt();
-            }
-        }
-        System.out.println(determinant(a, n));
-        in.close();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/maths/DeterminantOfMatrixTest.java b/src/test/java/com/thealgorithms/maths/DeterminantOfMatrixTest.java
new file mode 100644
index 000000000000..dd1c3ac4e605
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/DeterminantOfMatrixTest.java
@@ -0,0 +1,50 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class DeterminantOfMatrixTest {
+
+    @Test
+    public void testDeterminant2x2Matrix() {
+        int[][] matrix = {{1, 2}, {3, 4}};
+        int expected = -2;
+        assertEquals(expected, DeterminantOfMatrix.determinant(matrix, 2));
+    }
+
+    @Test
+    public void testDeterminant3x3Matrix() {
+        int[][] matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+        int expected = 0;
+        assertEquals(expected, DeterminantOfMatrix.determinant(matrix, 3));
+    }
+
+    @Test
+    public void testDeterminant3x3MatrixNonZero() {
+        int[][] matrix = {{1, 2, 3}, {0, 1, 4}, {5, 6, 0}};
+        int expected = 1;
+        assertEquals(expected, DeterminantOfMatrix.determinant(matrix, 3));
+    }
+
+    @Test
+    public void testDeterminant1x1Matrix() {
+        int[][] matrix = {{7}};
+        int expected = 7;
+        assertEquals(expected, DeterminantOfMatrix.determinant(matrix, 1));
+    }
+
+    @Test
+    public void testDeterminant4x4Matrix() {
+        int[][] matrix = {{1, 0, 0, 1}, {0, 1, 0, 0}, {0, 0, 1, 0}, {1, 0, 0, 1}};
+        int expected = 0;
+        assertEquals(expected, DeterminantOfMatrix.determinant(matrix, 4));
+    }
+
+    @Test
+    public void testDeterminant4x4MatrixZero() {
+        int[][] matrix = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};
+        int expected = 0;
+        assertEquals(expected, DeterminantOfMatrix.determinant(matrix, 4));
+    }
+}

From 4e720565276b68e8725658e690425baa63bacc2b Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 24 Aug 2024 10:53:35 +0200
Subject: [PATCH 0315/1338] refactor: `FindKthNumber` (#5374)

---
 .../thealgorithms/maths/FindKthNumber.java    | 90 ++++++++-----------
 .../maths/FindKthNumberTest.java              | 59 ++++++++++++
 2 files changed, 98 insertions(+), 51 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/FindKthNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/FindKthNumber.java b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
index daea3f96332b..a9b267677eac 100644
--- a/src/main/java/com/thealgorithms/maths/FindKthNumber.java
+++ b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
@@ -1,10 +1,9 @@
 package com.thealgorithms.maths;
 
-import java.util.Arrays;
 import java.util.Random;
 
 /**
- * use quick sort algorithm to get kth largest or kth smallest element in given array
+ * Use a quicksort-based approach to identify the k-th largest or k-th max element within the provided array.
  */
 public final class FindKthNumber {
     private FindKthNumber() {
@@ -12,66 +11,55 @@ private FindKthNumber() {
 
     private static final Random RANDOM = new Random();
 
-    public static void main(String[] args) {
-        /* generate an array with random size and random elements */
-        int[] nums = generateArray(100);
-
-        /* get 3th largest element */
-        int kth = 3;
-        int kthMaxIndex = nums.length - kth;
-        int targetMax = findKthMax(nums, kthMaxIndex);
-
-        /* get 3th smallest element */
-        int kthMinIndex = kth - 1;
-        int targetMin = findKthMax(nums, kthMinIndex);
+    public static int findKthMax(int[] array, int k) {
+        if (k <= 0 || k > array.length) {
+            throw new IllegalArgumentException("k must be between 1 and the size of the array");
+        }
 
-        Arrays.sort(nums);
-        assert nums[kthMaxIndex] == targetMax;
-        assert nums[kthMinIndex] == targetMin;
+        // Convert k-th largest to index for QuickSelect
+        return quickSelect(array, 0, array.length - 1, array.length - k);
     }
 
-    private static int[] generateArray(int capacity) {
-        int size = RANDOM.nextInt(capacity) + 1;
-        int[] array = new int[size];
-
-        for (int i = 0; i < size; i++) {
-            array[i] = RANDOM.nextInt() % 100;
+    private static int quickSelect(int[] array, int left, int right, int kSmallest) {
+        if (left == right) {
+            return array[left];
         }
-        return array;
-    }
 
-    private static int findKthMax(int[] nums, int k) {
-        int start = 0;
-        int end = nums.length;
-        while (start < end) {
-            int pivot = partition(nums, start, end);
-            if (k == pivot) {
-                return nums[pivot];
-            } else if (k > pivot) {
-                start = pivot + 1;
-            } else {
-                end = pivot;
-            }
+        // Randomly select a pivot index
+        int pivotIndex = left + RANDOM.nextInt(right - left + 1);
+        pivotIndex = partition(array, left, right, pivotIndex);
+
+        if (kSmallest == pivotIndex) {
+            return array[kSmallest];
+        } else if (kSmallest < pivotIndex) {
+            return quickSelect(array, left, pivotIndex - 1, kSmallest);
+        } else {
+            return quickSelect(array, pivotIndex + 1, right, kSmallest);
         }
-        return -1;
     }
 
-    private static int partition(int[] nums, int start, int end) {
-        int pivot = nums[start];
-        int j = start;
-        for (int i = start + 1; i < end; i++) {
-            if (nums[i] < pivot) {
-                j++;
-                swap(nums, i, j);
+    private static int partition(int[] array, int left, int right, int pivotIndex) {
+        int pivotValue = array[pivotIndex];
+        // Move pivot to end
+        swap(array, pivotIndex, right);
+        int storeIndex = left;
+
+        // Move all smaller elements to the left
+        for (int i = left; i < right; i++) {
+            if (array[i] < pivotValue) {
+                swap(array, storeIndex, i);
+                storeIndex++;
             }
         }
-        swap(nums, start, j);
-        return j;
+
+        // Move pivot to its final place
+        swap(array, storeIndex, right);
+        return storeIndex;
     }
 
-    private static void swap(int[] nums, int a, int b) {
-        int tmp = nums[a];
-        nums[a] = nums[b];
-        nums[b] = tmp;
+    private static void swap(int[] array, int i, int j) {
+        int temp = array[i];
+        array[i] = array[j];
+        array[j] = temp;
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java b/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java
new file mode 100644
index 000000000000..ddf62ff1e33a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java
@@ -0,0 +1,59 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.Arrays;
+import java.util.Random;
+import org.junit.jupiter.api.Test;
+
+public class FindKthNumberTest {
+    @Test
+    public void testFindKthMaxTypicalCases() {
+        int[] array1 = {3, 2, 1, 4, 5};
+        assertEquals(3, FindKthNumber.findKthMax(array1, 3));
+        assertEquals(4, FindKthNumber.findKthMax(array1, 2));
+        assertEquals(5, FindKthNumber.findKthMax(array1, 1));
+
+        int[] array2 = {7, 5, 8, 2, 1, 6};
+        assertEquals(5, FindKthNumber.findKthMax(array2, 4));
+        assertEquals(6, FindKthNumber.findKthMax(array2, 3));
+        assertEquals(8, FindKthNumber.findKthMax(array2, 1));
+    }
+
+    @Test
+    public void testFindKthMaxEdgeCases() {
+        int[] array1 = {1};
+        assertEquals(1, FindKthNumber.findKthMax(array1, 1));
+
+        int[] array2 = {5, 3};
+        assertEquals(5, FindKthNumber.findKthMax(array2, 1));
+        assertEquals(3, FindKthNumber.findKthMax(array2, 2));
+    }
+
+    @Test
+    public void testFindKthMaxInvalidK() {
+        int[] array = {1, 2, 3, 4, 5};
+        assertThrows(IllegalArgumentException.class, () -> FindKthNumber.findKthMax(array, 0));
+        assertThrows(IllegalArgumentException.class, () -> FindKthNumber.findKthMax(array, 6));
+    }
+
+    @Test
+    public void testFindKthMaxLargeArray() {
+        int[] array = generateArray(1000);
+        int k = new Random().nextInt(array.length);
+        int result = FindKthNumber.findKthMax(array, k);
+        Arrays.sort(array);
+        assertEquals(array[array.length - k], result);
+    }
+
+    public static int[] generateArray(int capacity) {
+        int size = new Random().nextInt(capacity) + 1;
+        int[] array = new int[size];
+
+        for (int i = 0; i < size; i++) {
+            array[i] = new Random().nextInt(100); // Ensure positive values for testing
+        }
+        return array;
+    }
+}

From 75355e87b6658e19164866bfcf31b9f5bbd0051d Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 24 Aug 2024 10:57:40 +0200
Subject: [PATCH 0316/1338] refactor: `PasswordGen` (#5373)

---
 .../com/thealgorithms/others/PasswordGen.java | 33 ++++++++++++-------
 .../thealgorithms/others/PasswordGenTest.java | 23 +++++++++++--
 2 files changed, 43 insertions(+), 13 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/PasswordGen.java b/src/main/java/com/thealgorithms/others/PasswordGen.java
index 7d21f112d480..da9f21bc918f 100644
--- a/src/main/java/com/thealgorithms/others/PasswordGen.java
+++ b/src/main/java/com/thealgorithms/others/PasswordGen.java
@@ -12,21 +12,32 @@
  * @date 2017.10.25
  */
 final class PasswordGen {
+    private static final String UPPERCASE_LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+    private static final String LOWERCASE_LETTERS = "abcdefghijklmnopqrstuvwxyz";
+    private static final String DIGITS = "0123456789";
+    private static final String SPECIAL_CHARACTERS = "!@#$%^&*(){}?";
+    private static final String ALL_CHARACTERS = UPPERCASE_LETTERS + LOWERCASE_LETTERS + DIGITS + SPECIAL_CHARACTERS;
+
     private PasswordGen() {
     }
 
-    static String generatePassword(int minLength, int maxLength) {
-        Random random = new Random();
-
-        String upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
-        String lower = "abcdefghijklmnopqrstuvwxyz";
-        String numbers = "0123456789";
-        String specialChars = "!@#$%^&*(){}?";
+    /**
+     * Generates a random password with a length between minLength and maxLength.
+     *
+     * @param minLength The minimum length of the password.
+     * @param maxLength The maximum length of the password.
+     * @return A randomly generated password.
+     * @throws IllegalArgumentException if minLength is greater than maxLength or if either is non-positive.
+     */
+    public static String generatePassword(int minLength, int maxLength) {
+        if (minLength > maxLength || minLength <= 0 || maxLength <= 0) {
+            throw new IllegalArgumentException("Incorrect length parameters: minLength must be <= maxLength and both must be > 0");
+        }
 
-        String allChars = upper + lower + numbers + specialChars;
+        Random random = new Random();
 
-        List<Character> letters = new ArrayList<Character>();
-        for (char c : allChars.toCharArray()) {
+        List<Character> letters = new ArrayList<>();
+        for (char c : ALL_CHARACTERS.toCharArray()) {
             letters.add(c);
         }
 
@@ -36,7 +47,7 @@ static String generatePassword(int minLength, int maxLength) {
 
         // Note that size of the password is also random
         for (int i = random.nextInt(maxLength - minLength) + minLength; i > 0; --i) {
-            password.append(letters.get(random.nextInt(letters.size())));
+            password.append(ALL_CHARACTERS.charAt(random.nextInt(ALL_CHARACTERS.length())));
         }
 
         return password.toString();
diff --git a/src/test/java/com/thealgorithms/others/PasswordGenTest.java b/src/test/java/com/thealgorithms/others/PasswordGenTest.java
index 57de329c8f09..76492556e75f 100644
--- a/src/test/java/com/thealgorithms/others/PasswordGenTest.java
+++ b/src/test/java/com/thealgorithms/others/PasswordGenTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.others;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -10,7 +11,7 @@ public class PasswordGenTest {
     @Test
     public void failGenerationWithSameMinMaxLengthTest() {
         int length = 10;
-        assertThrows(IllegalArgumentException.class, () -> { PasswordGen.generatePassword(length, length); });
+        assertThrows(IllegalArgumentException.class, () -> PasswordGen.generatePassword(length, length));
     }
 
     @Test
@@ -23,7 +24,7 @@ public void generateOneCharacterPassword() {
     public void failGenerationWithMinLengthSmallerThanMaxLengthTest() {
         int minLength = 10;
         int maxLength = 5;
-        assertThrows(IllegalArgumentException.class, () -> { PasswordGen.generatePassword(minLength, maxLength); });
+        assertThrows(IllegalArgumentException.class, () -> PasswordGen.generatePassword(minLength, maxLength));
     }
 
     @Test
@@ -31,4 +32,22 @@ public void generatePasswordNonEmptyTest() {
         String tempPassword = PasswordGen.generatePassword(8, 16);
         assertTrue(tempPassword.length() != 0);
     }
+
+    @Test
+    public void testGeneratePasswordWithMinGreaterThanMax() {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> PasswordGen.generatePassword(12, 8));
+        assertEquals("Incorrect length parameters: minLength must be <= maxLength and both must be > 0", exception.getMessage());
+    }
+
+    @Test
+    public void testGeneratePasswordWithNegativeLength() {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> PasswordGen.generatePassword(-5, 10));
+        assertEquals("Incorrect length parameters: minLength must be <= maxLength and both must be > 0", exception.getMessage());
+    }
+
+    @Test
+    public void testGeneratePasswordWithZeroLength() {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> PasswordGen.generatePassword(0, 0));
+        assertEquals("Incorrect length parameters: minLength must be <= maxLength and both must be > 0", exception.getMessage());
+    }
 }

From a7cd97d75e530ad36056c97516a0967b03c6194c Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 24 Aug 2024 10:57:54 +0200
Subject: [PATCH 0317/1338] refactor: fix typo (#5372)

---
 .../others/{GuassLegendre.java => GaussLegendre.java}     | 4 ++--
 src/main/java/com/thealgorithms/strings/Isomorphic.java   | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)
 rename src/main/java/com/thealgorithms/others/{GuassLegendre.java => GaussLegendre.java} (94%)

diff --git a/src/main/java/com/thealgorithms/others/GuassLegendre.java b/src/main/java/com/thealgorithms/others/GaussLegendre.java
similarity index 94%
rename from src/main/java/com/thealgorithms/others/GuassLegendre.java
rename to src/main/java/com/thealgorithms/others/GaussLegendre.java
index 5ecfdf2b84cc..b56b51f158fb 100644
--- a/src/main/java/com/thealgorithms/others/GuassLegendre.java
+++ b/src/main/java/com/thealgorithms/others/GaussLegendre.java
@@ -6,8 +6,8 @@
  *
  * @author AKS1996
  */
-public final class GuassLegendre {
-    private GuassLegendre() {
+public final class GaussLegendre {
+    private GaussLegendre() {
     }
 
     public static void main(String[] args) {
diff --git a/src/main/java/com/thealgorithms/strings/Isomorphic.java b/src/main/java/com/thealgorithms/strings/Isomorphic.java
index 088addc6ea45..ccd686170715 100644
--- a/src/main/java/com/thealgorithms/strings/Isomorphic.java
+++ b/src/main/java/com/thealgorithms/strings/Isomorphic.java
@@ -17,8 +17,8 @@ public static boolean checkStrings(String s, String t) {
         // To mark the characters of string using MAP
         // character of first string as KEY and another as VALUE
         // now check occurence by keeping the track with SET data structure
-        Map<Character, Character> characterMap = new HashMap<Character, Character>();
-        Set<Character> trackUinqueCharacter = new HashSet<Character>();
+        Map<Character, Character> characterMap = new HashMap<>();
+        Set<Character> trackUniqueCharacter = new HashSet<>();
 
         for (int i = 0; i < s.length(); i++) {
             if (characterMap.containsKey(s.charAt(i))) {
@@ -26,13 +26,13 @@ public static boolean checkStrings(String s, String t) {
                     return false;
                 }
             } else {
-                if (trackUinqueCharacter.contains(t.charAt(i))) {
+                if (trackUniqueCharacter.contains(t.charAt(i))) {
                     return false;
                 }
 
                 characterMap.put(s.charAt(i), t.charAt(i));
             }
-            trackUinqueCharacter.add(t.charAt(i));
+            trackUniqueCharacter.add(t.charAt(i));
         }
         return true;
     }

From b231a72d449420c6dc7004bc5969285aea7ec956 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 24 Aug 2024 15:08:22 +0200
Subject: [PATCH 0318/1338] refactor: `NonRepeatingElement` (#5375)

---
 .../maths/NonRepeatingElement.java            | 105 ++++++++----------
 .../maths/NonRepeatingElementTest.java        |  30 +++++
 2 files changed, 75 insertions(+), 60 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/NonRepeatingElementTest.java

diff --git a/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java b/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
index 5f1190d67de0..9c95ebde3740 100644
--- a/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
+++ b/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java
@@ -1,76 +1,61 @@
 package com.thealgorithms.maths;
 
-import java.util.Scanner;
-
-/*
- * Find the 2 elements which are non repeating in an array
+/**
+ * Find the 2 elements which are non-repeating in an array
  * Reason to use bitwise operator: It makes our program faster as we are operating on bits and not
  * on actual numbers.
+ *
+ * Explanation of the code:
+ * Let us assume we have an array [1, 2, 1, 2, 3, 4]
+ * Property of XOR: num ^ num = 0.
+ * If we XOR all the elements of the array, we will be left with 3 ^ 4 as 1 ^ 1
+ * and 2 ^ 2 would give 0. Our task is to find num1 and num2 from the result of 3 ^ 4 = 7.
+ * We need to find the two's complement of 7 and find the rightmost set bit, i.e., (num & (-num)).
+ * Two's complement of 7 is 001, and hence res = 1. There can be 2 options when we Bitwise AND this res
+ * with all the elements in our array:
+ * 1. The result will be a non-zero number.
+ * 2. The result will be 0.
+ * In the first case, we will XOR our element with the first number (which is initially 0).
+ * In the second case, we will XOR our element with the second number (which is initially 0).
+ * This is how we will get non-repeating elements with the help of bitwise operators.
  */
 public final class NonRepeatingElement {
     private NonRepeatingElement() {
     }
 
-    public static void main(String[] args) {
-        try (Scanner sc = new Scanner(System.in)) {
-            int i;
-            int res = 0;
-            System.out.println("Enter the number of elements in the array");
-            int n = sc.nextInt();
-            if ((n & 1) == 1) {
-                // Not allowing odd number of elements as we are expecting 2 non repeating
-                // numbers
-                System.out.println("Array should contain even number of elements");
-                return;
-            }
-            int[] arr = new int[n];
+    /**
+     * Finds the two non-repeating elements in the array.
+     *
+     * @param arr The input array containing exactly two non-repeating elements and all other elements repeating.
+     * @return An array containing the two non-repeating elements.
+     * @throws IllegalArgumentException if the input array length is odd.
+     */
+    public static int[] findNonRepeatingElements(int[] arr) {
+        if (arr.length % 2 != 0) {
+            throw new IllegalArgumentException("Array should contain an even number of elements");
+        }
 
-            System.out.println("Enter " + n + " elements in the array. NOTE: Only 2 elements should not repeat");
-            for (i = 0; i < n; i++) {
-                arr[i] = sc.nextInt();
-            }
+        int xorResult = 0;
 
-            // Find XOR of the 2 non repeating elements
-            for (i = 0; i < n; i++) {
-                res ^= arr[i];
-            }
-
-            // Finding the rightmost set bit
-            res = res & (-res);
-            int num1 = 0;
-            int num2 = 0;
+        // Find XOR of all elements
+        for (int num : arr) {
+            xorResult ^= num;
+        }
 
-            for (i = 0; i < n; i++) {
-                if ((res & arr[i]) > 0) { // Case 1 explained below
-                    num1 ^= arr[i];
-                } else {
-                    num2 ^= arr[i]; // Case 2 explained below
-                }
+        // Find the rightmost set bit
+        int rightmostSetBit = xorResult & (-xorResult);
+        int num1 = 0;
+        int num2 = 0;
+
+        // Divide the elements into two groups and XOR them
+        for (int num : arr) {
+            if ((num & rightmostSetBit) != 0) {
+                num1 ^= num;
+            } else {
+                num2 ^= num;
             }
-
-            System.out.println("The two non repeating elements are " + num1 + " and " + num2);
         }
+
+        return new int[] {num1, num2};
     }
-    /*
-     * Explanation of the code:
-     * let us assume we have an array [1,2,1,2,3,4]
-     * Property of XOR: num ^ num = 0.
-     * If we XOR all the elemnets of the array we will be left with 3 ^ 4 as 1 ^ 1
-     * and 2 ^ 2 would give
-     * 0. Our task is to find num1 and num2 from the result of 3 ^ 4 = 7. We need to
-     * find two's
-     * complement of 7 and find the rightmost set bit. i.e. (num & (-num)) Two's
-     * complement of 7 is 001
-     * and hence res = 1. There can be 2 options when we Bitise AND this res with
-     * all the elements in our
-     * array
-     * 1. Result will come non zero number
-     * 2. Result will be 0.
-     * In the first case we will XOR our element with the first number (which is
-     * initially 0)
-     * In the second case we will XOR our element with the second number(which is
-     * initially 0)
-     * This is how we will get non repeating elements with the help of bitwise
-     * operators.
-     */
 }
diff --git a/src/test/java/com/thealgorithms/maths/NonRepeatingElementTest.java b/src/test/java/com/thealgorithms/maths/NonRepeatingElementTest.java
new file mode 100644
index 000000000000..5f35cfe68a7a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/NonRepeatingElementTest.java
@@ -0,0 +1,30 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class NonRepeatingElementTest {
+
+    private record TestData(int[] input, int[] expected) {
+    }
+
+    private static Stream<TestData> provideTestCases() {
+        return Stream.of(new TestData(new int[] {1, 2, 1, 3, 2, 4}, new int[] {3, 4}), new TestData(new int[] {-1, -2, -1, -3, -2, -4}, new int[] {-3, -4}), new TestData(new int[] {-1, 2, 2, -3, -1, 4}, new int[] {-3, 4}));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testFindNonRepeatingElements(TestData testData) {
+        int[] result = NonRepeatingElement.findNonRepeatingElements(testData.input);
+        assertArrayEquals(testData.expected, result);
+    }
+
+    @Test
+    public void testFindNonRepeatingElementsWithLargeNumbers() {
+        assertArrayEquals(new int[] {200000, 400000}, NonRepeatingElement.findNonRepeatingElements(new int[] {100000, 200000, 100000, 300000, 400000, 300000}));
+    }
+}

From 38688440efa9225069cb4f4c0dfaa742b14cf674 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 08:29:17 +0200
Subject: [PATCH 0319/1338] refactor: `TwoPointers` (#5380)

---
 .../com/thealgorithms/others/TwoPointers.java | 28 ++++-------
 .../thealgorithms/others/TwoPointersTest.java | 50 +++++++++++++++----
 2 files changed, 50 insertions(+), 28 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/TwoPointers.java b/src/main/java/com/thealgorithms/others/TwoPointers.java
index 01391ec72e78..c551408c38b9 100644
--- a/src/main/java/com/thealgorithms/others/TwoPointers.java
+++ b/src/main/java/com/thealgorithms/others/TwoPointers.java
@@ -1,39 +1,33 @@
 package com.thealgorithms.others;
 
-import java.util.Arrays;
-
 /**
- * The two pointer technique is a useful tool to utilize when searching for
+ * The two-pointer technique is a useful tool to utilize when searching for
  * pairs in a sorted array.
  *
  * <p>
- * link: https://www.geeksforgeeks.org/two-pointers-technique/
+ * Link: https://www.geeksforgeeks.org/two-pointers-technique/
  */
 final class TwoPointers {
     private TwoPointers() {
     }
 
     /**
-     * Given a sorted array arr (sorted in ascending order). Find if there
-     * exists any pair of elements such that their sum is equal to key.
+     * Given a sorted array arr (sorted in ascending order), find if there exists
+     * any pair of elements such that their sum is equal to the key.
      *
-     * @param arr the array contains elements
+     * @param arr the array containing elements (must be sorted in ascending order)
      * @param key the number to search
-     * @return {@code true} if there exists a pair of elements, {@code false}
-     * otherwise.
+     * @return {@code true} if there exists a pair of elements, {@code false} otherwise.
      */
     public static boolean isPairedSum(int[] arr, int key) {
-        /* array sorting is necessary for this algorithm to function correctly */
-        Arrays.sort(arr);
-        int i = 0;
-        /* index of first element */
-        int j = arr.length - 1;
-        /* index of last element */
+        int i = 0; // index of the first element
+        int j = arr.length - 1; // index of the last element
 
         while (i < j) {
-            if (arr[i] + arr[j] == key) {
+            int sum = arr[i] + arr[j];
+            if (sum == key) {
                 return true;
-            } else if (arr[i] + arr[j] < key) {
+            } else if (sum < key) {
                 i++;
             } else {
                 j--;
diff --git a/src/test/java/com/thealgorithms/others/TwoPointersTest.java b/src/test/java/com/thealgorithms/others/TwoPointersTest.java
index e8fe41b0bdaf..3a174e0cd19e 100644
--- a/src/test/java/com/thealgorithms/others/TwoPointersTest.java
+++ b/src/test/java/com/thealgorithms/others/TwoPointersTest.java
@@ -8,37 +8,65 @@
 public class TwoPointersTest {
 
     @Test
-    void twoPointersFirstTestCase() {
+    void testPositivePairExists() {
         int[] arr = {2, 6, 9, 22, 121};
         int key = 28;
         assertTrue(TwoPointers.isPairedSum(arr, key));
     }
 
     @Test
-    void twoPointersSecondTestCase() {
-        int[] arr = {-1, -12, 12, 0, 8};
+    void testNegativePairExists() {
+        int[] arr = {-12, -1, 0, 8, 12};
         int key = 0;
         assertTrue(TwoPointers.isPairedSum(arr, key));
     }
 
     @Test
-    void twoPointersThirdTestCase() {
-        int[] arr = {12, 35, 12, 152, 0};
+    void testPairDoesNotExist() {
+        int[] arr = {0, 12, 12, 35, 152};
         int key = 13;
         assertFalse(TwoPointers.isPairedSum(arr, key));
     }
 
     @Test
-    void twoPointersFourthTestCase() {
-        int[] arr = {-2, 5, -1, 52, 31};
-        int key = -3;
+    void testNegativeSumPair() {
+        int[] arr = {-10, -3, 1, 2, 5, 9};
+        int key = -8;
         assertTrue(TwoPointers.isPairedSum(arr, key));
     }
 
     @Test
-    void twoPointersFiftiethTestCase() {
-        int[] arr = {25, 1, 0, 61, 21};
-        int key = 12;
+    void testPairDoesNotExistWithPositiveSum() {
+        int[] arr = {1, 2, 3, 4, 5};
+        int key = 10;
         assertFalse(TwoPointers.isPairedSum(arr, key));
     }
+
+    @Test
+    void testEmptyArray() {
+        int[] arr = {};
+        int key = 5;
+        assertFalse(TwoPointers.isPairedSum(arr, key));
+    }
+
+    @Test
+    void testSingleElementArray() {
+        int[] arr = {5};
+        int key = 5;
+        assertFalse(TwoPointers.isPairedSum(arr, key));
+    }
+
+    @Test
+    void testArrayWithDuplicateElements() {
+        int[] arr = {1, 1, 3, 5, 5};
+        int key = 6;
+        assertTrue(TwoPointers.isPairedSum(arr, key));
+    }
+
+    @Test
+    void testPairExistsAtEdges() {
+        int[] arr = {1, 3, 4, 7, 8};
+        int key = 9;
+        assertTrue(TwoPointers.isPairedSum(arr, key));
+    }
 }

From a8d3b6ad2d598e0fd04ae7e9f078d2017a9eac27 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 08:43:39 +0200
Subject: [PATCH 0320/1338] test: cleanup `ReverseNumberTest` (#5381)

---
 .../maths/ReverseNumberTest.java              | 28 ++++++++-----------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/src/test/java/com/thealgorithms/maths/ReverseNumberTest.java b/src/test/java/com/thealgorithms/maths/ReverseNumberTest.java
index e870962b185e..f9538b9fd829 100644
--- a/src/test/java/com/thealgorithms/maths/ReverseNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/ReverseNumberTest.java
@@ -3,27 +3,21 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import java.util.HashMap;
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.ValueSource;
 
 public class ReverseNumberTest {
 
-    @Test
-    public void testReverseNumber() {
-        HashMap<Integer, Integer> testCases = new HashMap<>();
-        testCases.put(0, 0);
-        testCases.put(1, 1);
-        testCases.put(10, 1);
-        testCases.put(123, 321);
-        testCases.put(7890, 987);
-
-        for (final var tc : testCases.entrySet()) {
-            assertEquals(ReverseNumber.reverseNumber(tc.getKey()), tc.getValue());
-        }
+    @ParameterizedTest
+    @CsvSource({"0, 0", "1, 1", "10, 1", "123, 321", "7890, 987"})
+    public void testReverseNumber(int input, int expected) {
+        assertEquals(expected, ReverseNumber.reverseNumber(input));
     }
 
-    @Test
-    public void testReverseNumberThrowsExceptionForNegativeInput() {
-        assertThrows(IllegalArgumentException.class, () -> ReverseNumber.reverseNumber(-1));
+    @ParameterizedTest
+    @ValueSource(ints = {-1, -123, -7890})
+    public void testReverseNumberThrowsExceptionForNegativeInput(int input) {
+        assertThrows(IllegalArgumentException.class, () -> ReverseNumber.reverseNumber(input));
     }
 }

From e5c0e4bff0a31f0eec4a65de947946450c833b5e Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 08:56:02 +0200
Subject: [PATCH 0321/1338] test: cleanup `PrimeFactorizationTest` (#5382)

---
 .../maths/PrimeFactorizationTest.java         | 40 +++++++++----------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java b/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java
index abe6068c2022..6994379d736a 100644
--- a/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java
+++ b/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java
@@ -1,36 +1,32 @@
 package com.thealgorithms.maths;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class PrimeFactorizationTest {
 
-    @Test
-    void testpFactorsMustReturnEmptyList() {
-        // given
-        int n = 0;
-
-        // then
-        assertTrue(PrimeFactorization.pfactors(n).isEmpty());
+    @ParameterizedTest
+    @MethodSource("provideNumbersAndFactors")
+    void testPrimeFactorization(int number, List<Integer> expectedFactors) {
+        assertEquals(expectedFactors, PrimeFactorization.pfactors(number), "Prime factors for number: " + number);
     }
 
-    @Test
-    void testpFactorsMustReturnNonEmptyList() {
-        // given
-        int n = 198;
-        int expectedListSize = 4;
+    @ParameterizedTest
+    @MethodSource("provideNumbersAndSizes")
+    void testPrimeFactorsSize(int number, int expectedSize) {
+        assertEquals(expectedSize, PrimeFactorization.pfactors(number).size(), "Size of prime factors list for number: " + number);
+    }
 
-        // when
-        List<Integer> actualResultList = PrimeFactorization.pfactors(n);
+    private static Stream<Arguments> provideNumbersAndFactors() {
+        return Stream.of(Arguments.of(0, List.of()), Arguments.of(1, List.of()), Arguments.of(2, List.of(2)), Arguments.of(3, List.of(3)), Arguments.of(4, List.of(2, 2)), Arguments.of(18, List.of(2, 3, 3)), Arguments.of(100, List.of(2, 2, 5, 5)), Arguments.of(198, List.of(2, 3, 3, 11)));
+    }
 
-        // then
-        assertEquals(expectedListSize, actualResultList.size());
-        assertEquals(2, actualResultList.get(0));
-        assertEquals(3, actualResultList.get(1));
-        assertEquals(3, actualResultList.get(2));
-        assertEquals(11, actualResultList.get(3));
+    private static Stream<Arguments> provideNumbersAndSizes() {
+        return Stream.of(Arguments.of(2, 1), Arguments.of(3, 1), Arguments.of(4, 2), Arguments.of(18, 3), Arguments.of(100, 4), Arguments.of(198, 4));
     }
 }

From e1d8b6f8a7c5dfb09691c719c3a1ed31aee79ea4 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 09:07:02 +0200
Subject: [PATCH 0322/1338] refactor: `FordFulkerson` (#5384)

---
 .../dynamicprogramming/FordFulkerson.java     | 90 +++++++-----------
 .../dynamicprogramming/FordFulkersonTest.java | 94 +++++++++++++++++++
 2 files changed, 128 insertions(+), 56 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/FordFulkersonTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java b/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
index 6168ec6ec09f..76995f1ce37e 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
@@ -2,76 +2,54 @@
 
 import java.util.LinkedList;
 import java.util.Queue;
-import java.util.Vector;
 
 public final class FordFulkerson {
-    private FordFulkerson() {
-    }
-
-    static final int INF = 987654321;
-    // edges
-    static int vertexCount;
-    static int[][] capacity;
-    static int[][] flow;
+    private static final int INF = Integer.MAX_VALUE;
 
-    public static void main(String[] args) {
-        System.out.println("Vertex Count : 6");
-        vertexCount = 6;
-        capacity = new int[vertexCount][vertexCount];
-
-        capacity[0][1] = 12;
-        capacity[0][3] = 13;
-        capacity[1][2] = 10;
-        capacity[2][3] = 13;
-        capacity[2][4] = 3;
-        capacity[2][5] = 15;
-        capacity[3][2] = 7;
-        capacity[3][4] = 15;
-        capacity[4][5] = 17;
-
-        System.out.println("Max capacity in networkFlow : " + networkFlow(0, 5));
+    private FordFulkerson() {
     }
 
-    private static int networkFlow(int source, int sink) {
-        flow = new int[vertexCount][vertexCount];
+    public static int networkFlow(int vertexCount, int[][] capacity, int[][] flow, int source, int sink) {
         int totalFlow = 0;
+
         while (true) {
-            Vector<Integer> parent = new Vector<>(vertexCount);
-            for (int i = 0; i < vertexCount; i++) {
-                parent.add(-1);
-            }
-            Queue<Integer> q = new LinkedList<>();
-            parent.set(source, source);
-            q.add(source);
-            while (!q.isEmpty() && parent.get(sink) == -1) {
-                int here = q.peek();
-                q.poll();
-                for (int there = 0; there < vertexCount; ++there) {
-                    if (capacity[here][there] - flow[here][there] > 0 && parent.get(there) == -1) {
-                        q.add(there);
-                        parent.set(there, here);
+            int[] parent = new int[vertexCount];
+            boolean[] visited = new boolean[vertexCount];
+            Queue<Integer> queue = new LinkedList<>();
+
+            queue.add(source);
+            visited[source] = true;
+            parent[source] = -1;
+
+            while (!queue.isEmpty() && !visited[sink]) {
+                int current = queue.poll();
+
+                for (int next = 0; next < vertexCount; next++) {
+                    if (!visited[next] && capacity[current][next] - flow[current][next] > 0) {
+                        queue.add(next);
+                        visited[next] = true;
+                        parent[next] = current;
                     }
                 }
             }
-            if (parent.get(sink) == -1) {
-                break;
+
+            if (!visited[sink]) {
+                break; // No more augmenting paths
             }
 
-            int amount = INF;
-            String printer = "path : ";
-            StringBuilder sb = new StringBuilder();
-            for (int p = sink; p != source; p = parent.get(p)) {
-                amount = Math.min(capacity[parent.get(p)][p] - flow[parent.get(p)][p], amount);
-                sb.append(p + "-");
+            int pathFlow = INF;
+            for (int v = sink; v != source; v = parent[v]) {
+                int u = parent[v];
+                pathFlow = Math.min(pathFlow, capacity[u][v] - flow[u][v]);
             }
-            sb.append(source);
-            for (int p = sink; p != source; p = parent.get(p)) {
-                flow[parent.get(p)][p] += amount;
-                flow[p][parent.get(p)] -= amount;
+
+            for (int v = sink; v != source; v = parent[v]) {
+                int u = parent[v];
+                flow[u][v] += pathFlow;
+                flow[v][u] -= pathFlow;
             }
-            totalFlow += amount;
-            printer += sb.reverse() + " / max flow : " + totalFlow;
-            System.out.println(printer);
+
+            totalFlow += pathFlow;
         }
 
         return totalFlow;
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/FordFulkersonTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/FordFulkersonTest.java
new file mode 100644
index 000000000000..d4d38ed5ccde
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/FordFulkersonTest.java
@@ -0,0 +1,94 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class FordFulkersonTest {
+    @Test
+    public void testMaxFlow() {
+        int vertexCount = 6;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // Setting up the capacity graph
+        capacity[0][1] = 12;
+        capacity[0][3] = 13;
+        capacity[1][2] = 10;
+        capacity[2][3] = 13;
+        capacity[2][4] = 3;
+        capacity[2][5] = 15;
+        capacity[3][2] = 7;
+        capacity[3][4] = 15;
+        capacity[4][5] = 17;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 5);
+        assertEquals(23, maxFlow);
+    }
+
+    @Test
+    public void testNoFlow() {
+        int vertexCount = 6;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // No connections between source and sink
+        capacity[0][1] = 10;
+        capacity[2][3] = 10;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 1, 4);
+        assertEquals(0, maxFlow);
+    }
+
+    @Test
+    public void testSinglePath() {
+        int vertexCount = 6;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // Setting up a single path from source to sink
+        capacity[0][1] = 5;
+        capacity[1][2] = 5;
+        capacity[2][3] = 5;
+        capacity[3][4] = 5;
+        capacity[4][5] = 5;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 5);
+        assertEquals(5, maxFlow);
+    }
+
+    @Test
+    public void testParallelPaths() {
+        int vertexCount = 4;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // Setting up parallel paths from source to sink
+        capacity[0][1] = 10;
+        capacity[0][2] = 10;
+        capacity[1][3] = 10;
+        capacity[2][3] = 10;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 3);
+        assertEquals(20, maxFlow);
+    }
+
+    @Test
+    public void testComplexNetwork() {
+        int vertexCount = 5;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // Complex network
+        capacity[0][1] = 10;
+        capacity[0][2] = 10;
+        capacity[1][3] = 4;
+        capacity[1][4] = 8;
+        capacity[2][4] = 9;
+        capacity[3][2] = 6;
+        capacity[3][4] = 10;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 4);
+        assertEquals(19, maxFlow);
+    }
+}

From 0b0b26e3fed34432b16ad7c1ab36839e824998b9 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 09:12:17 +0200
Subject: [PATCH 0323/1338] refactor: `ReverseStackUsingRecursion` (#5386)

---
 .../others/ReverseStackUsingRecursion.java    | 73 +++++++------------
 .../ReverseStackUsingRecursionTest.java       | 58 +++++++++++++++
 2 files changed, 85 insertions(+), 46 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java

diff --git a/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java b/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
index 2c26f8eae4dc..de36673512a0 100644
--- a/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
+++ b/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
@@ -1,63 +1,44 @@
 package com.thealgorithms.others;
 
-/* Program to reverse a Stack using Recursion*/
 import java.util.Stack;
 
+/**
+ * Class that provides methods to reverse a stack using recursion.
+ */
 public final class ReverseStackUsingRecursion {
     private ReverseStackUsingRecursion() {
     }
 
-    // Stack
-    private static Stack<Integer> stack = new Stack<>();
-
-    // Main function
-    public static void main(String[] args) {
-        // To Create a Dummy Stack containing integers from 0-9
-        for (int i = 0; i < 10; i++) {
-            stack.push(i);
-        }
-        System.out.println("STACK");
-
-        // To print that dummy Stack
-        for (int k = 9; k >= 0; k--) {
-            System.out.println(k);
+    /**
+     * Reverses the elements of the given stack using recursion.
+     *
+     * @param stack the stack to be reversed
+     * @throws IllegalArgumentException if the stack is null
+     */
+    public static void reverse(Stack<Integer> stack) {
+        if (stack == null) {
+            throw new IllegalArgumentException("Stack cannot be null");
         }
-
-        // Reverse Function called
-        reverseUsingRecursion(stack);
-
-        System.out.println("REVERSED STACK : ");
-        // To print reversed  stack
-        while (!stack.isEmpty()) {
-            System.out.println(stack.pop());
+        if (!stack.isEmpty()) {
+            int topElement = stack.pop();
+            reverse(stack);
+            insertAtBottom(stack, topElement);
         }
     }
 
-    // Function Used to reverse Stack Using Recursion
-    private static void reverseUsingRecursion(Stack<Integer> stack) {
-        if (stack.isEmpty()) { // If stack is empty then return
-            return;
-        }
-        /* All items are stored in call stack until we reach the end*/
-
-        int temptop = stack.peek();
-        stack.pop();
-        reverseUsingRecursion(stack); // Recursion call
-        insertAtEnd(temptop); // Insert items held in call stack one by one into stack
-    }
-
-    // Function used to insert element at the end of stack
-    private static void insertAtEnd(int temptop) {
+    /**
+     * Inserts an element at the bottom of the given stack.
+     *
+     * @param stack    the stack where the element will be inserted
+     * @param element  the element to be inserted at the bottom
+     */
+    private static void insertAtBottom(Stack<Integer> stack, int element) {
         if (stack.isEmpty()) {
-            stack.push(temptop); // If stack is empty push the element
+            stack.push(element);
         } else {
-            int temp = stack.peek();
-            /* All the items are stored in call stack until we reach end*/
-            stack.pop();
-
-            insertAtEnd(temptop); // Recursive call
-
-            stack.push(temp);
+            int topElement = stack.pop();
+            insertAtBottom(stack, element);
+            stack.push(topElement);
         }
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java b/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java
new file mode 100644
index 000000000000..23b99ae87d35
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Stack;
+import org.junit.jupiter.api.Test;
+
+public class ReverseStackUsingRecursionTest {
+
+    @Test
+    void testReverseWithMultipleElements() {
+        Stack<Integer> stack = new Stack<>();
+        for (int i = 0; i < 5; i++) {
+            stack.push(i);
+        }
+
+        ReverseStackUsingRecursion.reverse(stack);
+
+        for (int i = 0; i < 5; i++) {
+            assertEquals(i, stack.pop());
+        }
+        assertTrue(stack.isEmpty());
+    }
+
+    @Test
+    void testReverseWithSingleElement() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(1);
+
+        ReverseStackUsingRecursion.reverse(stack);
+
+        assertEquals(1, stack.pop());
+        assertTrue(stack.isEmpty());
+    }
+
+    @Test
+    void testReverseWithEmptyStack() {
+        Stack<Integer> stack = new Stack<>();
+
+        ReverseStackUsingRecursion.reverse(stack);
+
+        assertTrue(stack.isEmpty());
+    }
+
+    @Test
+    void testReverseWithNullStack() {
+        Stack<Integer> stack = null;
+
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> ReverseStackUsingRecursion.reverse(stack));
+
+        String expectedMessage = "Stack cannot be null";
+        String actualMessage = exception.getMessage();
+
+        assertTrue(actualMessage.contains(expectedMessage));
+    }
+}

From 69e1fe9cfb3e5e07c3bfb6d31e25a6a1440ee274 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 09:16:14 +0200
Subject: [PATCH 0324/1338] refactor: `LowestBasePalindrome` (#5385)

---
 .../others/LowestBasePalindrome.java          |  81 ++++++++-----
 .../others/LowestBasePalindromeTest.java      | 107 +++++++++---------
 2 files changed, 102 insertions(+), 86 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java b/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
index c8328a4ee552..76d1ed4aba1d 100644
--- a/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
+++ b/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.others;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * @brief Class for finding the lowest base in which a given integer is a palindrome.
@@ -10,45 +11,61 @@ public final class LowestBasePalindrome {
     private LowestBasePalindrome() {
     }
 
+    /**
+     * Validates the base, ensuring it is greater than 1.
+     *
+     * @param base the base to be checked
+     * @throws IllegalArgumentException if the base is less than or equal to 1
+     */
     private static void checkBase(int base) {
         if (base <= 1) {
-            throw new IllegalArgumentException("base must be greater than 1.");
+            throw new IllegalArgumentException("Base must be greater than 1.");
         }
     }
 
+    /**
+     * Validates the number, ensuring it is non-negative.
+     *
+     * @param number the number to be checked
+     * @throws IllegalArgumentException if the number is negative
+     */
     private static void checkNumber(int number) {
         if (number < 0) {
-            throw new IllegalArgumentException("number must be nonnegative.");
+            throw new IllegalArgumentException("Number must be non-negative.");
         }
     }
 
     /**
-     * @brief computes the representation of the input number in given base
-     * @param number the input number
-     * @param base the given base
-     * @exception IllegalArgumentException number is negative or base is less than 2
-     * @return the list containing the digits of the input number in the given base, the most
-     *     significant digit is at the end of the array
+     * Computes the digits of a given number in a specified base.
+     *
+     * @param number the number to be converted
+     * @param base the base to be used for the conversion
+     * @return a list of digits representing the number in the given base, with the most
+     *         significant digit at the end of the list
+     * @throws IllegalArgumentException if the number is negative or the base is less than 2
      */
-    public static ArrayList<Integer> computeDigitsInBase(int number, int base) {
+    public static List<Integer> computeDigitsInBase(int number, int base) {
         checkNumber(number);
         checkBase(base);
-        var result = new ArrayList<Integer>();
+
+        List<Integer> digits = new ArrayList<>();
         while (number > 0) {
-            result.add(number % base);
+            digits.add(number % base);
             number /= base;
         }
-        return result;
+        return digits;
     }
 
     /**
-     * @brief checks if the input array is a palindrome
-     * @brief list the input array
-     * @return true, if the input array is a palindrome, false otherwise
+     * Checks if a list of integers is palindromic.
+     *
+     * @param list the list of integers to be checked
+     * @return {@code true} if the list is a palindrome, {@code false} otherwise
      */
-    public static boolean isPalindromic(ArrayList<Integer> list) {
-        for (int pos = 0; pos < list.size() / 2; ++pos) {
-            if (list.get(pos) != list.get(list.size() - 1 - pos)) {
+    public static boolean isPalindromic(List<Integer> list) {
+        int size = list.size();
+        for (int i = 0; i < size / 2; i++) {
+            if (!list.get(i).equals(list.get(size - 1 - i))) {
                 return false;
             }
         }
@@ -56,12 +73,12 @@ public static boolean isPalindromic(ArrayList<Integer> list) {
     }
 
     /**
-     * @brief checks if representation of the input number in given base is a palindrome
-     * @param number the input number
-     * @param base the given base
-     * @exception IllegalArgumentException number is negative or base is less than 2
-     * @return true, if the input number represented in the given base is a palindrome, false
-     *     otherwise
+     * Checks if the representation of a given number in a specified base is palindromic.
+     *
+     * @param number the number to be checked
+     * @param base the base in which the number will be represented
+     * @return {@code true} if the number is palindromic in the specified base, {@code false} otherwise
+     * @throws IllegalArgumentException if the number is negative or the base is less than 2
      */
     public static boolean isPalindromicInBase(int number, int base) {
         checkNumber(number);
@@ -72,7 +89,7 @@ public static boolean isPalindromicInBase(int number, int base) {
         }
 
         if (number % base == 0) {
-            // the last digit of number written in base is 0
+            // If the last digit of the number in the given base is 0, it can't be palindromic
             return false;
         }
 
@@ -80,16 +97,18 @@ public static boolean isPalindromicInBase(int number, int base) {
     }
 
     /**
-     * @brief finds the smallest base for which the representation of the input number is a
-     * palindrome
-     * @param number the input number
-     * @exception IllegalArgumentException number is negative
-     * @return the smallest base for which the representation of the input number is a palindrome
+     * Finds the smallest base in which the representation of a given number is palindromic.
+     *
+     * @param number the number to be checked
+     * @return the smallest base in which the number is a palindrome
+     * @throws IllegalArgumentException if the number is negative
      */
     public static int lowestBasePalindrome(int number) {
+        checkNumber(number);
+
         int base = 2;
         while (!isPalindromicInBase(number, base)) {
-            ++base;
+            base++;
         }
         return base;
     }
diff --git a/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java b/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java
index c8e173ab8362..1014f39a26bc 100644
--- a/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java
+++ b/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java
@@ -2,79 +2,76 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HashMap;
-import org.junit.jupiter.api.Test;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class LowestBasePalindromeTest {
-    @Test
-    public void testIsPalindromicPositive() {
-        assertTrue(LowestBasePalindrome.isPalindromic(new ArrayList<Integer>()));
-        assertTrue(LowestBasePalindrome.isPalindromic(new ArrayList<Integer>(Arrays.asList(1))));
-        assertTrue(LowestBasePalindrome.isPalindromic(new ArrayList<Integer>(Arrays.asList(1, 1))));
-        assertTrue(LowestBasePalindrome.isPalindromic(new ArrayList<Integer>(Arrays.asList(1, 2, 1))));
-        assertTrue(LowestBasePalindrome.isPalindromic(new ArrayList<Integer>(Arrays.asList(1, 2, 2, 1))));
+
+    @ParameterizedTest
+    @MethodSource("provideListsForIsPalindromicPositive")
+    public void testIsPalindromicPositive(List<Integer> list) {
+        assertTrue(LowestBasePalindrome.isPalindromic(list));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideListsForIsPalindromicNegative")
+    public void testIsPalindromicNegative(List<Integer> list) {
+        assertFalse(LowestBasePalindrome.isPalindromic(list));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideNumbersAndBasesForIsPalindromicInBasePositive")
+    public void testIsPalindromicInBasePositive(int number, int base) {
+        assertTrue(LowestBasePalindrome.isPalindromicInBase(number, base));
     }
 
-    @Test
-    public void testIsPalindromicNegative() {
-        assertFalse(LowestBasePalindrome.isPalindromic(new ArrayList<Integer>(Arrays.asList(1, 2))));
-        assertFalse(LowestBasePalindrome.isPalindromic(new ArrayList<Integer>(Arrays.asList(1, 2, 1, 1))));
+    @ParameterizedTest
+    @MethodSource("provideNumbersAndBasesForIsPalindromicInBaseNegative")
+    public void testIsPalindromicInBaseNegative(int number, int base) {
+        assertFalse(LowestBasePalindrome.isPalindromicInBase(number, base));
     }
 
-    @Test
-    public void testIsPalindromicInBasePositive() {
-        assertTrue(LowestBasePalindrome.isPalindromicInBase(101, 10));
-        assertTrue(LowestBasePalindrome.isPalindromicInBase(1, 190));
-        assertTrue(LowestBasePalindrome.isPalindromicInBase(0, 11));
-        assertTrue(LowestBasePalindrome.isPalindromicInBase(10101, 10));
-        assertTrue(LowestBasePalindrome.isPalindromicInBase(23, 22));
+    @ParameterizedTest
+    @MethodSource("provideNumbersAndBasesForExceptions")
+    public void testIsPalindromicInBaseThrowsException(int number, int base) {
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalArgumentException.class, () -> LowestBasePalindrome.isPalindromicInBase(number, base));
     }
 
-    @Test
-    public void testIsPalindromicInBaseNegative() {
-        assertFalse(LowestBasePalindrome.isPalindromicInBase(1010, 10));
-        assertFalse(LowestBasePalindrome.isPalindromicInBase(123, 10));
+    @ParameterizedTest
+    @MethodSource("provideNumbersForLowestBasePalindrome")
+    public void testLowestBasePalindrome(int number, int expectedBase) {
+        assertEquals(expectedBase, LowestBasePalindrome.lowestBasePalindrome(number));
     }
 
-    @Test
-    public void testIsPalindromicInBaseThrowsExceptionForNegativeNumbers() {
-        assertThrows(IllegalArgumentException.class, () -> LowestBasePalindrome.isPalindromicInBase(-1, 5));
+    private static Stream<Arguments> provideListsForIsPalindromicPositive() {
+        return Stream.of(Arguments.of(new ArrayList<>()), Arguments.of(new ArrayList<>(List.of(1))), Arguments.of(new ArrayList<>(Arrays.asList(1, 1))), Arguments.of(new ArrayList<>(Arrays.asList(1, 2, 1))), Arguments.of(new ArrayList<>(Arrays.asList(1, 2, 2, 1))));
     }
 
-    @Test
-    public void testIsPalindromicInBaseThrowsExceptionForWrongBases() {
-        assertThrows(IllegalArgumentException.class, () -> LowestBasePalindrome.isPalindromicInBase(10, 1));
+    private static Stream<Arguments> provideListsForIsPalindromicNegative() {
+        return Stream.of(Arguments.of(new ArrayList<>(Arrays.asList(1, 2))), Arguments.of(new ArrayList<>(Arrays.asList(1, 2, 1, 1))));
     }
 
-    @Test
-    public void testLowestBasePalindrome() {
-        HashMap<Integer, Integer> testCases = new HashMap<>();
-        testCases.put(0, 2);
-        testCases.put(1, 2);
-        testCases.put(2, 3);
-        testCases.put(3, 2);
-        testCases.put(10, 3);
-        testCases.put(11, 10);
-        testCases.put(15, 2);
-        testCases.put(39, 12);
-        testCases.put(44, 10);
-        testCases.put(58, 28);
-        testCases.put(69, 22);
-        testCases.put(79, 78);
-        testCases.put(87, 28);
-        testCases.put(90, 14);
-        testCases.put(5591, 37);
-        testCases.put(5895, 130);
-        testCases.put(9950, 198);
-        testCases.put(9974, 4986);
+    private static Stream<Arguments> provideNumbersAndBasesForIsPalindromicInBasePositive() {
+        return Stream.of(Arguments.of(101, 10), Arguments.of(1, 190), Arguments.of(0, 11), Arguments.of(10101, 10), Arguments.of(23, 22));
+    }
+
+    private static Stream<Arguments> provideNumbersAndBasesForIsPalindromicInBaseNegative() {
+        return Stream.of(Arguments.of(1010, 10), Arguments.of(123, 10));
+    }
+
+    private static Stream<Arguments> provideNumbersAndBasesForExceptions() {
+        return Stream.of(Arguments.of(-1, 5), Arguments.of(10, 1));
+    }
 
-        for (final var tc : testCases.entrySet()) {
-            assertEquals(LowestBasePalindrome.lowestBasePalindrome(tc.getKey()), tc.getValue());
-        }
+    private static Stream<Arguments> provideNumbersForLowestBasePalindrome() {
+        return Stream.of(Arguments.of(0, 2), Arguments.of(1, 2), Arguments.of(2, 3), Arguments.of(3, 2), Arguments.of(10, 3), Arguments.of(11, 10), Arguments.of(15, 2), Arguments.of(39, 12), Arguments.of(44, 10), Arguments.of(58, 28), Arguments.of(69, 22), Arguments.of(79, 78), Arguments.of(87, 28),
+            Arguments.of(90, 14), Arguments.of(5591, 37), Arguments.of(5895, 130), Arguments.of(9950, 198), Arguments.of(9974, 4986));
     }
 }

From 101cb950ae9988d957e7a4f4244d65a46d8fab98 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 10:34:12 +0200
Subject: [PATCH 0325/1338] refactor: `RootPrecision` (#5383)

---
 DIRECTORY.md                                  |  1 -
 .../thealgorithms/others/RootPrecision.java   | 38 -------------------
 2 files changed, 39 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/others/RootPrecision.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 656597c3b20a..30b107a177fb 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -439,7 +439,6 @@
             * [RemoveDuplicateFromString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java)
             * [ReturnSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReturnSubsequence.java)
             * [ReverseStackUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
-            * [RootPrecision](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RootPrecision.java)
             * [RotateMatrixBy90Degrees](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java)
             * [SieveOfEratosthenes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java)
             * [SkylineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SkylineProblem.java)
diff --git a/src/main/java/com/thealgorithms/others/RootPrecision.java b/src/main/java/com/thealgorithms/others/RootPrecision.java
deleted file mode 100644
index bc195ffca5ae..000000000000
--- a/src/main/java/com/thealgorithms/others/RootPrecision.java
+++ /dev/null
@@ -1,38 +0,0 @@
-package com.thealgorithms.others;
-
-import java.util.Scanner;
-
-public final class RootPrecision {
-    private RootPrecision() {
-    }
-
-    public static void main(String[] args) {
-        // take input
-        Scanner scn = new Scanner(System.in);
-
-        // n is the input number
-        int n = scn.nextInt();
-
-        // p is precision value for eg - p is 3 in 2.564 and 5 in 3.80870.
-        int p = scn.nextInt();
-        System.out.println(squareRoot(n, p));
-
-        scn.close();
-    }
-
-    public static double squareRoot(int n, int p) {
-        // rv means return value
-        double rv;
-
-        double root = Math.pow(n, 0.5);
-
-        // calculate precision to power of 10 and then multiply it with root value.
-        int precision = (int) Math.pow(10, p);
-        root = root * precision;
-        /*typecast it into integer then divide by precision and again typecast into double
-    so as to have decimal points upto p precision */
-
-        rv = (int) root;
-        return rv / precision;
-    }
-}

From f3851e3adc9b6054b9868e0c454e5b7a52f6fccd Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 21:33:41 +0200
Subject: [PATCH 0326/1338] refactor: `RemoveDuplicateFromString` (#5387)

---
 .../others/RemoveDuplicateFromString.java     | 39 +++++-----------
 .../others/RemoveDuplicateFromStringTest.java | 44 +++++++++++++++++++
 2 files changed, 55 insertions(+), 28 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java

diff --git a/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java b/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java
index 695a10648b6c..5b6466f6fa07 100644
--- a/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java
+++ b/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java
@@ -1,8 +1,5 @@
 package com.thealgorithms.others;
 
-import java.io.BufferedReader;
-import java.io.InputStreamReader;
-
 /**
  * @author Varun Upadhyay (https://github.com/varunu28)
  */
@@ -10,38 +7,24 @@ public final class RemoveDuplicateFromString {
     private RemoveDuplicateFromString() {
     }
 
-    public static void main(String[] args) throws Exception {
-        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
-        String inpStr = br.readLine();
-
-        System.out.println("Actual string is: " + inpStr);
-        System.out.println("String after removing duplicates: " + removeDuplicate(inpStr));
-
-        br.close();
-    }
-
     /**
-     * This method produces a string after removing all the duplicate characters
-     * from input string and returns it Example: Input String - "aabbbccccddddd"
-     * Output String - "abcd"
+     * Removes duplicate characters from the given string.
      *
-     * @param s String from which duplicate characters have to be removed
-     * @return string with only unique characters
+     * @param input The input string from which duplicate characters need to be removed.
+     * @return A string containing only unique characters from the input, in their original order.
      */
-    public static String removeDuplicate(String s) {
-        if (s == null || s.isEmpty()) {
-            return s;
+    public static String removeDuplicate(String input) {
+        if (input == null || input.isEmpty()) {
+            return input;
         }
 
-        StringBuilder sb = new StringBuilder();
-        int n = s.length();
-
-        for (int i = 0; i < n; i++) {
-            if (sb.toString().indexOf(s.charAt(i)) == -1) {
-                sb.append(s.charAt(i));
+        StringBuilder uniqueChars = new StringBuilder();
+        for (char c : input.toCharArray()) {
+            if (uniqueChars.indexOf(String.valueOf(c)) == -1) {
+                uniqueChars.append(c); // Append character if it's not already in the StringBuilder
             }
         }
 
-        return sb.toString();
+        return uniqueChars.toString();
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java b/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java
new file mode 100644
index 000000000000..3401a51c56c9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+class RemoveDuplicateFromStringTest {
+
+    @Test
+    void testEmptyString() {
+        assertEquals("", RemoveDuplicateFromString.removeDuplicate(""));
+    }
+
+    @Test
+    void testNullString() {
+        assertNull(RemoveDuplicateFromString.removeDuplicate(null));
+    }
+
+    @Test
+    void testSingleCharacterString() {
+        assertEquals("a", RemoveDuplicateFromString.removeDuplicate("a"));
+    }
+
+    @Test
+    void testStringWithNoDuplicates() {
+        assertEquals("abc", RemoveDuplicateFromString.removeDuplicate("abc"));
+    }
+
+    @Test
+    void testStringWithDuplicates() {
+        assertEquals("abcd", RemoveDuplicateFromString.removeDuplicate("aabbbccccddddd"));
+    }
+
+    @Test
+    void testStringWithAllSameCharacters() {
+        assertEquals("a", RemoveDuplicateFromString.removeDuplicate("aaaaa"));
+    }
+
+    @Test
+    void testStringWithMixedCase() {
+        assertEquals("abAB", RemoveDuplicateFromString.removeDuplicate("aabABAB"));
+    }
+}

From 25b8010ea80a22ea65c4866c21a36984c8f9946b Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 21:44:55 +0200
Subject: [PATCH 0327/1338] refactor: cleanup `EulersFunction` (#5388)

---
 .../thealgorithms/others/EulersFunction.java  | 20 +++++---
 .../others/EulersFunctionTest.java            | 48 ++++++++-----------
 2 files changed, 35 insertions(+), 33 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/EulersFunction.java b/src/main/java/com/thealgorithms/others/EulersFunction.java
index f08e5e4fa395..7a6f49d41758 100644
--- a/src/main/java/com/thealgorithms/others/EulersFunction.java
+++ b/src/main/java/com/thealgorithms/others/EulersFunction.java
@@ -1,12 +1,19 @@
 package com.thealgorithms.others;
 
 /**
- * @brief utility class for <a href="https://en.wikipedia.org/wiki/Euler%27s_totient_function">Euler's totient function</a>
+ * Utility class for computing
+ * <a href="https://en.wikipedia.org/wiki/Euler%27s_totient_function">Euler's totient function</a>.
  */
 public final class EulersFunction {
     private EulersFunction() {
     }
 
+    /**
+     * Validates that the input is a positive integer.
+     *
+     * @param n the input number to validate
+     * @throws IllegalArgumentException if {@code n} is non-positive
+     */
     private static void checkInput(int n) {
         if (n <= 0) {
             throw new IllegalArgumentException("n must be positive.");
@@ -14,11 +21,12 @@ private static void checkInput(int n) {
     }
 
     /**
-     * @brief computes the value of Euler's totient function for given input
-     * @details has time complexity of O(sqrt(n))
-     * @param n the input
-     * @exception IllegalArgumentException n is non-positive
-     * @return the value of Euler's totient function for the input
+     * Computes the value of Euler's totient function for a given input.
+     * This function has a time complexity of O(sqrt(n)).
+     *
+     * @param n the input number
+     * @return the value of Euler's totient function for the given input
+     * @throws IllegalArgumentException if {@code n} is non-positive
      */
     public static int getEuler(int n) {
         checkInput(n);
diff --git a/src/test/java/com/thealgorithms/others/EulersFunctionTest.java b/src/test/java/com/thealgorithms/others/EulersFunctionTest.java
index b80926b8c2dc..655c67c83aaa 100644
--- a/src/test/java/com/thealgorithms/others/EulersFunctionTest.java
+++ b/src/test/java/com/thealgorithms/others/EulersFunctionTest.java
@@ -3,37 +3,31 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import java.util.HashMap;
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class EulersFunctionTest {
-    @Test
-    public void testGetEuler() {
-        HashMap<Integer, Integer> testCases = new HashMap<>();
-        testCases.put(1, 1);
-        testCases.put(2, 1);
-        testCases.put(3, 2);
-        testCases.put(4, 2);
-        testCases.put(5, 4);
-        testCases.put(6, 2);
-        testCases.put(10, 4);
-        testCases.put(21, 12);
-        testCases.put(69, 44);
-        testCases.put(47, 46);
-        testCases.put(46, 22);
-        testCases.put(55, 40);
-        testCases.put(34, 16);
-        testCases.put(20, 8);
-        testCases.put(20, 8);
-        testCases.put(1024, 512);
 
-        for (final var tc : testCases.entrySet()) {
-            assertEquals(tc.getValue(), EulersFunction.getEuler(tc.getKey()));
-        }
+    @ParameterizedTest
+    @MethodSource("provideNumbersForGetEuler")
+    void testGetEuler(int input, int expected) {
+        assertEquals(expected, EulersFunction.getEuler(input));
     }
 
-    @Test
-    public void testGetEulerThrowsExceptionForNonPositiveInput() {
-        assertThrows(IllegalArgumentException.class, () -> EulersFunction.getEuler(0));
+    @ParameterizedTest
+    @MethodSource("provideInvalidNumbersForGetEuler")
+    void testGetEulerThrowsExceptionForNonPositiveInput(int input) {
+        assertThrows(IllegalArgumentException.class, () -> EulersFunction.getEuler(input));
+    }
+
+    private static Stream<Arguments> provideNumbersForGetEuler() {
+        return Stream.of(Arguments.of(1, 1), Arguments.of(2, 1), Arguments.of(3, 2), Arguments.of(4, 2), Arguments.of(5, 4), Arguments.of(6, 2), Arguments.of(10, 4), Arguments.of(21, 12), Arguments.of(69, 44), Arguments.of(47, 46), Arguments.of(46, 22), Arguments.of(55, 40), Arguments.of(34, 16),
+            Arguments.of(20, 8), Arguments.of(1024, 512));
+    }
+
+    private static Stream<Arguments> provideInvalidNumbersForGetEuler() {
+        return Stream.of(Arguments.of(0), Arguments.of(-1), Arguments.of(-10));
     }
 }

From 3187b1f99c9a652d802265edf69421b137ea2344 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 22:01:52 +0200
Subject: [PATCH 0328/1338] refactor: `DecimalToAnyUsingStack` (#5392)

---
 .../stacks/DecimalToAnyUsingStack.java        | 51 +++++++------------
 .../stacks/DecimalToAnyUsingStackTest.java    | 45 ++++++++++++++++
 2 files changed, 62 insertions(+), 34 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/stacks/DecimalToAnyUsingStackTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java b/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java
index 41d1c6408ee5..ff6402c92695 100644
--- a/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java
+++ b/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java
@@ -6,50 +6,33 @@ public final class DecimalToAnyUsingStack {
     private DecimalToAnyUsingStack() {
     }
 
-    public static void main(String[] args) {
-        assert convert(0, 2).equals("0");
-        assert convert(30, 2).equals("11110");
-        assert convert(30, 8).equals("36");
-        assert convert(30, 10).equals("30");
-        assert convert(30, 16).equals("1E");
-    }
-
     /**
-     * Convert decimal number to another radix
+     * Convert a decimal number to another radix.
      *
      * @param number the number to be converted
      * @param radix the radix
-     * @return another radix
-     * @throws ArithmeticException if <tt>number</tt> or <tt>radius</tt> is
-     * invalid
+     * @return the number represented in the new radix as a String
+     * @throws IllegalArgumentException if <tt>number</tt> is negative or <tt>radix</tt> is not between 2 and 16 inclusive
      */
-    private static String convert(int number, int radix) {
+    public static String convert(int number, int radix) {
+        if (number < 0) {
+            throw new IllegalArgumentException("Number must be non-negative.");
+        }
         if (radix < 2 || radix > 16) {
-            throw new ArithmeticException(String.format("Invalid input -> number:%d,radius:%d", number, radix));
+            throw new IllegalArgumentException(String.format("Invalid radix: %d. Radix must be between 2 and 16.", radix));
+        }
+
+        if (number == 0) {
+            return "0";
         }
-        char[] tables = {
-            '0',
-            '1',
-            '2',
-            '3',
-            '4',
-            '5',
-            '6',
-            '7',
-            '8',
-            '9',
-            'A',
-            'B',
-            'C',
-            'D',
-            'E',
-            'F',
-        };
+
+        char[] tables = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
+
         Stack<Character> bits = new Stack<>();
-        do {
+        while (number > 0) {
             bits.push(tables[number % radix]);
             number = number / radix;
-        } while (number != 0);
+        }
 
         StringBuilder result = new StringBuilder();
         while (!bits.isEmpty()) {
diff --git a/src/test/java/com/thealgorithms/stacks/DecimalToAnyUsingStackTest.java b/src/test/java/com/thealgorithms/stacks/DecimalToAnyUsingStackTest.java
new file mode 100644
index 000000000000..4bd9f2af0376
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/DecimalToAnyUsingStackTest.java
@@ -0,0 +1,45 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class DecimalToAnyUsingStackTest {
+
+    @Test
+    void testConvertToBinary() {
+        assertEquals("0", DecimalToAnyUsingStack.convert(0, 2));
+        assertEquals("11110", DecimalToAnyUsingStack.convert(30, 2));
+    }
+
+    @Test
+    void testConvertToOctal() {
+        assertEquals("36", DecimalToAnyUsingStack.convert(30, 8));
+    }
+
+    @Test
+    void testConvertToDecimal() {
+        assertEquals("30", DecimalToAnyUsingStack.convert(30, 10));
+    }
+
+    @Test
+    void testConvertToHexadecimal() {
+        assertEquals("1E", DecimalToAnyUsingStack.convert(30, 16));
+    }
+
+    @Test
+    void testInvalidRadix() {
+        IllegalArgumentException thrown = assertThrows(IllegalArgumentException.class, () -> DecimalToAnyUsingStack.convert(30, 1));
+        assertEquals("Invalid radix: 1. Radix must be between 2 and 16.", thrown.getMessage());
+
+        thrown = assertThrows(IllegalArgumentException.class, () -> DecimalToAnyUsingStack.convert(30, 17));
+        assertEquals("Invalid radix: 17. Radix must be between 2 and 16.", thrown.getMessage());
+    }
+
+    @Test
+    void testNegativeNumber() {
+        IllegalArgumentException thrown = assertThrows(IllegalArgumentException.class, () -> DecimalToAnyUsingStack.convert(-30, 2));
+        assertEquals("Number must be non-negative.", thrown.getMessage());
+    }
+}

From a5f57fbfde0d0e091358de4b4e41550f30dc8af1 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 22:08:10 +0200
Subject: [PATCH 0329/1338] refactor: `ArrayLeftRotationTest` (#5389)

---
 .../others/ArrayLeftRotation.java             | 42 ++++++++++++-------
 .../others/ArrayLeftRotationTest.java         |  7 ++++
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java b/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java
index f43841f1f184..b54cbec08f74 100644
--- a/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java
+++ b/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java
@@ -1,34 +1,44 @@
 package com.thealgorithms.others;
 
-/*
- * A left rotation operation on an array
- * shifts each of the array's elements
- * given integer n unit to the left.
+/**
+ * Provides a method to perform a left rotation on an array.
+ * A left rotation operation shifts each element of the array
+ * by a specified number of positions to the left.
  *
  * @author sangin-lee
  */
-
 public final class ArrayLeftRotation {
     private ArrayLeftRotation() {
     }
 
-    /*
-     * Returns the result of left rotation of given array arr and integer n
-     *
-     * @param arr : int[] given array
-     *
-     * @param n : int given integer
+    /**
+     * Performs a left rotation on the given array by the specified number of positions.
      *
-     * @return : int[] result of left rotation
+     * @param arr the array to be rotated
+     * @param n the number of positions to rotate the array to the left
+     * @return a new array containing the elements of the input array rotated to the left
      */
     public static int[] rotateLeft(int[] arr, int n) {
         int size = arr.length;
-        int[] dst = new int[size];
+
+        // Handle cases where array is empty or rotation count is zero
+        if (size == 0 || n <= 0) {
+            return arr.clone();
+        }
+
+        // Normalize the number of rotations
         n = n % size;
+        if (n == 0) {
+            return arr.clone();
+        }
+
+        int[] rotated = new int[size];
+
+        // Perform rotation
         for (int i = 0; i < size; i++) {
-            dst[i] = arr[n];
-            n = (n + 1) % size;
+            rotated[i] = arr[(i + n) % size];
         }
-        return dst;
+
+        return rotated;
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java b/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java
index 355f107ddb61..b31b7d825ed5 100644
--- a/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java
+++ b/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java
@@ -44,4 +44,11 @@ void testForHigherSizeStep() {
         int[] result = ArrayLeftRotation.rotateLeft(arr, n);
         assertArrayEquals(expected, result);
     }
+
+    @Test
+    void testForEmptyArray() {
+        int[] arr = {};
+        int[] result = ArrayLeftRotation.rotateLeft(arr, 3);
+        assertArrayEquals(arr, result);
+    }
 }

From 580aa0c9c5ed9753952993c42a6e0c09328adebf Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 22:14:33 +0200
Subject: [PATCH 0330/1338] refactor: `CheckVowels` (#5393)

---
 .../thealgorithms/strings/CheckVowels.java    | 20 +++++++++----------
 .../strings/CheckVowelsTest.java              | 18 ++++++++---------
 2 files changed, 17 insertions(+), 21 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/CheckVowels.java b/src/main/java/com/thealgorithms/strings/CheckVowels.java
index 44965cc9282c..21b536b5c7d5 100644
--- a/src/main/java/com/thealgorithms/strings/CheckVowels.java
+++ b/src/main/java/com/thealgorithms/strings/CheckVowels.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.strings;
 
-import java.util.Arrays;
-import java.util.HashSet;
 import java.util.Set;
 
 /**
@@ -10,24 +8,24 @@
  * alphabet. Wikipedia: https://en.wikipedia.org/wiki/Alphabetical_order
  */
 public final class CheckVowels {
+    private static final Set<Character> VOWELS = Set.of('a', 'e', 'i', 'o', 'u');
+
     private CheckVowels() {
     }
 
-    private static final Set<Character> VOWELS = new HashSet<>(Arrays.asList('a', 'e', 'i', 'o', 'u'));
-
     /**
-     * Check if a string is has vowels or not
+     * Checks if a string contains any vowels.
      *
-     * @param input a string
-     * @return {@code true} if given string has vowels, otherwise {@code false}
+     * @param input a string to check
+     * @return {@code true} if the given string contains at least one vowel, otherwise {@code false}
      */
     public static boolean hasVowels(String input) {
-        if (input == null) {
+        if (input == null || input.isEmpty()) {
             return false;
         }
-        input = input.toLowerCase();
-        for (int i = 0; i < input.length(); i++) {
-            if (VOWELS.contains(input.charAt(i))) {
+
+        for (char c : input.toLowerCase().toCharArray()) {
+            if (VOWELS.contains(c)) {
                 return true;
             }
         }
diff --git a/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java b/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java
index 713b53f0b634..ba510aa8e995 100644
--- a/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java
+++ b/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java
@@ -1,17 +1,15 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
-public class CheckVowelsTest {
+class CheckVowelsTest {
 
-    @Test
-    public void isVowel() {
-        assertTrue(CheckVowels.hasVowels("foo"));
-        assertTrue(CheckVowels.hasVowels("bar"));
-        assertFalse(CheckVowels.hasVowels("why"));
-        assertFalse(CheckVowels.hasVowels("myths"));
+    @ParameterizedTest
+    @CsvSource({"'foo', true", "'bar', true", "'why', false", "'myths', false", "'', false", "'AEIOU', true", "'bcdfghjklmnpqrstvwxyz', false", "'AeIoU', true"})
+    void testHasVowels(String input, boolean expected) {
+        assertEquals(CheckVowels.hasVowels(input), expected);
     }
 }

From 7e9cdad3ee205084822a46b45a21b2ed4467432e Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 25 Aug 2024 22:21:30 +0200
Subject: [PATCH 0331/1338] refactor: `BalancedBrackets` (#5391)

---
 .../stacks/BalancedBrackets.java              |  8 ++---
 .../stacks/BalancedBracketsTest.java          | 36 +++++++++++++++++++
 2 files changed, 38 insertions(+), 6 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/stacks/BalancedBracketsTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java b/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java
index a8f5254b22c5..d3077ff54135 100644
--- a/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java
+++ b/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java
@@ -59,26 +59,22 @@ public static boolean isBalanced(String brackets) {
             switch (bracket) {
             case '(':
             case '[':
+            case '<':
             case '{':
                 bracketsStack.push(bracket);
                 break;
             case ')':
             case ']':
+            case '>':
             case '}':
                 if (bracketsStack.isEmpty() || !isPaired(bracketsStack.pop(), bracket)) {
                     return false;
                 }
                 break;
             default:
-                /* other character is invalid */
                 return false;
             }
         }
         return bracketsStack.isEmpty();
     }
-
-    public static void main(String[] args) {
-        assert isBalanced("[()]{}{[()()]()}");
-        assert !isBalanced("[(])");
-    }
 }
diff --git a/src/test/java/com/thealgorithms/stacks/BalancedBracketsTest.java b/src/test/java/com/thealgorithms/stacks/BalancedBracketsTest.java
new file mode 100644
index 000000000000..33ef18af9c5f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/BalancedBracketsTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class BalancedBracketsTest {
+
+    @ParameterizedTest
+    @CsvSource({"(, )", "[, ]", "{, }", "<, >"})
+    void testIsPairedTrue(char opening, char closing) {
+        assertTrue(BalancedBrackets.isPaired(opening, closing));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"(, ]", "[, )", "{, >", "<, )", "a, b", "!, @"})
+    void testIsPairedFalse(char opening, char closing) {
+        assertFalse(BalancedBrackets.isPaired(opening, closing));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"'[()]{}{[()()]()}', true", "'()', true", "'[]', true", "'{}', true", "'<>', true", "'[{<>}]', true", "'', true", "'[(])', false", "'([)]', false", "'{[<]>}', false", "'[', false", "')', false", "'[{', false", "']', false", "'[a+b]', false", "'a+b', false"})
+    void testIsBalanced(String input, boolean expected) {
+        assertEquals(expected, BalancedBrackets.isBalanced(input));
+    }
+
+    @Test
+    void testIsBalancedNull() {
+        assertThrows(IllegalArgumentException.class, () -> BalancedBrackets.isBalanced(null));
+    }
+}

From 93e417544d8c695c4954ac1434d3596e418acfe8 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 07:26:01 +0200
Subject: [PATCH 0332/1338] refactor: `Anagrams` (#5390)

---
 .../com/thealgorithms/strings/Anagrams.java   | 193 +++++++++---------
 .../thealgorithms/strings/AnagramsTest.java   |  55 +++--
 2 files changed, 131 insertions(+), 117 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/Anagrams.java b/src/main/java/com/thealgorithms/strings/Anagrams.java
index f5e8fa84cd41..4b24979e2689 100644
--- a/src/main/java/com/thealgorithms/strings/Anagrams.java
+++ b/src/main/java/com/thealgorithms/strings/Anagrams.java
@@ -10,141 +10,130 @@
  * also the word binary into brainy and the word adobe into abode.
  * Reference from https://en.wikipedia.org/wiki/Anagram
  */
-public class Anagrams {
+public final class Anagrams {
+    private Anagrams() {
+    }
 
     /**
-     * 4 approaches are provided for anagram checking. approach 2 and approach 3 are similar but
-     * differ in running time.
-     * OUTPUT :
-     * first string ="deal" second string ="lead"
-     * Output: Anagram
-     * Input and output is constant for all four approaches
-     * 1st approach Time Complexity : O(n logn)
-     * Auxiliary Space Complexity : O(1)
-     * 2nd approach Time Complexity : O(n)
-     * Auxiliary Space Complexity : O(1)
-     * 3rd approach Time Complexity : O(n)
-     * Auxiliary Space Complexity : O(1)
-     * 4th approach Time Complexity : O(n)
-     * Auxiliary Space Complexity : O(n)
-     * 5th approach Time Complexity: O(n)
-     * Auxiliary Space Complexity: O(1)
+     * Checks if two strings are anagrams by sorting the characters and comparing them.
+     * Time Complexity: O(n log n)
+     * Space Complexity: O(n)
+     *
+     * @param s the first string
+     * @param t the second string
+     * @return true if the strings are anagrams, false otherwise
      */
-    public static void main(String[] args) {
-        String first = "deal";
-        String second = "lead";
-        // All the below methods takes input but doesn't return any output to the main method.
-        Anagrams nm = new Anagrams();
-        System.out.println(nm.approach2(first, second)); /* To activate methods for different approaches*/
-        System.out.println(nm.approach1(first, second)); /* To activate methods for different approaches*/
-        System.out.println(nm.approach3(first, second)); /* To activate methods for different approaches*/
-        System.out.println(nm.approach4(first, second)); /* To activate methods for different approaches*/
-    }
-
-    boolean approach1(String s, String t) {
+    public static boolean approach1(String s, String t) {
         if (s.length() != t.length()) {
             return false;
-        } else {
-            char[] c = s.toCharArray();
-            char[] d = t.toCharArray();
-            Arrays.sort(c);
-            Arrays.sort(d); /* In this approach the strings are stored in the character arrays and
-                               both the arrays are sorted. After that both the arrays are compared
-                               for checking anangram */
-
-            return Arrays.equals(c, d);
         }
+        char[] c = s.toCharArray();
+        char[] d = t.toCharArray();
+        Arrays.sort(c);
+        Arrays.sort(d);
+        return Arrays.equals(c, d);
     }
 
-    boolean approach2(String a, String b) {
-        if (a.length() != b.length()) {
+    /**
+     * Checks if two strings are anagrams by counting the frequency of each character.
+     * Time Complexity: O(n)
+     * Space Complexity: O(1)
+     *
+     * @param s the first string
+     * @param t the second string
+     * @return true if the strings are anagrams, false otherwise
+     */
+    public static boolean approach2(String s, String t) {
+        if (s.length() != t.length()) {
             return false;
-        } else {
-            int[] m = new int[26];
-            int[] n = new int[26];
-            for (char c : a.toCharArray()) {
-                m[c - 'a']++;
-            }
-            // In this approach the frequency of both the strings are stored and after that the
-            // frequencies are iterated from 0 to 26(from 'a' to 'z' ). If the frequencies match
-            // then anagram message is displayed in the form of boolean format Running time and
-            // space complexity of this algo is less as compared to others
-            for (char c : b.toCharArray()) {
-                n[c - 'a']++;
-            }
-            for (int i = 0; i < 26; i++) {
-                if (m[i] != n[i]) {
-                    return false;
-                }
+        }
+        int[] charCount = new int[26];
+        for (int i = 0; i < s.length(); i++) {
+            charCount[s.charAt(i) - 'a']++;
+            charCount[t.charAt(i) - 'a']--;
+        }
+        for (int count : charCount) {
+            if (count != 0) {
+                return false;
             }
-            return true;
         }
+        return true;
     }
 
-    boolean approach3(String s, String t) {
+    /**
+     * Checks if two strings are anagrams by counting the frequency of each character
+     * using a single array.
+     * Time Complexity: O(n)
+     * Space Complexity: O(1)
+     *
+     * @param s the first string
+     * @param t the second string
+     * @return true if the strings are anagrams, false otherwise
+     */
+    public static boolean approach3(String s, String t) {
         if (s.length() != t.length()) {
             return false;
         }
-        // this is similar to approach number 2 but here the string is not converted to character
-        // array
-        else {
-            int[] a = new int[26];
-            int[] b = new int[26];
-            int k = s.length();
-            for (int i = 0; i < k; i++) {
-                a[s.charAt(i) - 'a']++;
-                b[t.charAt(i) - 'a']++;
-            }
-            for (int i = 0; i < 26; i++) {
-                if (a[i] != b[i]) {
-                    return false;
-                }
+        int[] charCount = new int[26];
+        for (int i = 0; i < s.length(); i++) {
+            charCount[s.charAt(i) - 'a']++;
+            charCount[t.charAt(i) - 'a']--;
+        }
+        for (int count : charCount) {
+            if (count != 0) {
+                return false;
             }
-            return true;
         }
+        return true;
     }
 
-    boolean approach4(String s, String t) {
+    /**
+     * Checks if two strings are anagrams using a HashMap to store character frequencies.
+     * Time Complexity: O(n)
+     * Space Complexity: O(n)
+     *
+     * @param s the first string
+     * @param t the second string
+     * @return true if the strings are anagrams, false otherwise
+     */
+    public static boolean approach4(String s, String t) {
         if (s.length() != t.length()) {
             return false;
         }
-        // This approach is done using hashmap where frequencies are stored and checked iteratively
-        // and if all the frequencies of first string match with the second string then anagram
-        // message is displayed in boolean format
-        else {
-            HashMap<Character, Integer> nm = new HashMap<>();
-            HashMap<Character, Integer> kk = new HashMap<>();
-            for (char c : s.toCharArray()) {
-                nm.put(c, nm.getOrDefault(c, 0) + 1);
-            }
-            for (char c : t.toCharArray()) {
-                kk.put(c, kk.getOrDefault(c, 0) + 1);
+        HashMap<Character, Integer> charCountMap = new HashMap<>();
+        for (char c : s.toCharArray()) {
+            charCountMap.put(c, charCountMap.getOrDefault(c, 0) + 1);
+        }
+        for (char c : t.toCharArray()) {
+            if (!charCountMap.containsKey(c) || charCountMap.get(c) == 0) {
+                return false;
             }
-            // It checks for equal frequencies by comparing key-value pairs of two hashmaps
-            return nm.equals(kk);
+            charCountMap.put(c, charCountMap.get(c) - 1);
         }
+        return charCountMap.values().stream().allMatch(count -> count == 0);
     }
 
-    boolean approach5(String s, String t) {
+    /**
+     * Checks if two strings are anagrams using an array to track character frequencies.
+     * This approach optimizes space complexity by using only one array.
+     * Time Complexity: O(n)
+     * Space Complexity: O(1)
+     *
+     * @param s the first string
+     * @param t the second string
+     * @return true if the strings are anagrams, false otherwise
+     */
+    public static boolean approach5(String s, String t) {
         if (s.length() != t.length()) {
             return false;
         }
-        // Approach is different from above 4 aproaches.
-        // Here we initialize an array of size 26 where each element corresponds to the frequency of
-        // a character.
         int[] freq = new int[26];
-        // iterate through both strings, incrementing the frequency of each character in the first
-        // string and decrementing the frequency of each character in the second string.
         for (int i = 0; i < s.length(); i++) {
-            int pos1 = s.charAt(i) - 'a';
-            int pos2 = s.charAt(i) - 'a';
-            freq[pos1]++;
-            freq[pos2]--;
+            freq[s.charAt(i) - 'a']++;
+            freq[t.charAt(i) - 'a']--;
         }
-        // iterate through the frequency array and check if all the elements are zero, if so return
-        // true else false
-        for (int i = 0; i < 26; i++) {
-            if (freq[i] != 0) {
+        for (int count : freq) {
+            if (count != 0) {
                 return false;
             }
         }
diff --git a/src/test/java/com/thealgorithms/strings/AnagramsTest.java b/src/test/java/com/thealgorithms/strings/AnagramsTest.java
index ba530cffb017..88f6e0bb72ec 100644
--- a/src/test/java/com/thealgorithms/strings/AnagramsTest.java
+++ b/src/test/java/com/thealgorithms/strings/AnagramsTest.java
@@ -1,23 +1,48 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class AnagramsTest {
 
-    @Test
-    public void isAlphabetical() {
-        String input1 = "late";
-        Anagrams anagrams = new Anagrams();
-        assertTrue(anagrams.approach1(input1, "tale"));
-        assertTrue(anagrams.approach1(input1, "teal"));
-        assertTrue(anagrams.approach2(input1, "tale"));
-        assertTrue(anagrams.approach2(input1, "teal"));
-        assertTrue(anagrams.approach3(input1, "tale"));
-        assertTrue(anagrams.approach3(input1, "teal"));
-        assertTrue(anagrams.approach4(input1, "tale"));
-        assertTrue(anagrams.approach4(input1, "teal"));
-        assertTrue(anagrams.approach5(input1, "teal"));
+    record AnagramTestCase(String input1, String input2, boolean expected) {
+    }
+
+    private static Stream<AnagramTestCase> anagramTestData() {
+        return Stream.of(new AnagramTestCase("late", "tale", true), new AnagramTestCase("late", "teal", true), new AnagramTestCase("listen", "silent", true), new AnagramTestCase("hello", "olelh", true), new AnagramTestCase("hello", "world", false), new AnagramTestCase("deal", "lead", true),
+            new AnagramTestCase("binary", "brainy", true), new AnagramTestCase("adobe", "abode", true), new AnagramTestCase("cat", "act", true), new AnagramTestCase("cat", "cut", false));
+    }
+
+    @ParameterizedTest
+    @MethodSource("anagramTestData")
+    void testApproach1(AnagramTestCase testCase) {
+        assertEquals(testCase.expected(), Anagrams.approach1(testCase.input1(), testCase.input2()));
+    }
+
+    @ParameterizedTest
+    @MethodSource("anagramTestData")
+    void testApproach2(AnagramTestCase testCase) {
+        assertEquals(testCase.expected(), Anagrams.approach2(testCase.input1(), testCase.input2()));
+    }
+
+    @ParameterizedTest
+    @MethodSource("anagramTestData")
+    void testApproach3(AnagramTestCase testCase) {
+        assertEquals(testCase.expected(), Anagrams.approach3(testCase.input1(), testCase.input2()));
+    }
+
+    @ParameterizedTest
+    @MethodSource("anagramTestData")
+    void testApproach4(AnagramTestCase testCase) {
+        assertEquals(testCase.expected(), Anagrams.approach4(testCase.input1(), testCase.input2()));
+    }
+
+    @ParameterizedTest
+    @MethodSource("anagramTestData")
+    void testApproach5(AnagramTestCase testCase) {
+        assertEquals(testCase.expected(), Anagrams.approach5(testCase.input1(), testCase.input2()));
     }
 }

From 6edc009765a3f42428649431abdf0fa6c27d94af Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 08:37:00 +0200
Subject: [PATCH 0333/1338] test: `LongestAlternatingSubsequenceTest` (#5399)

---
 .../LongestAlternatingSubsequence.java        | 80 +++++++++----------
 .../LongestAlternatingSubsequenceTest.java    | 22 +++++
 2 files changed, 62 insertions(+), 40 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
index d6f9b2acf768..08039b85ce40 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java
@@ -1,38 +1,48 @@
 package com.thealgorithms.dynamicprogramming;
 
-/*
-
- * Problem Statement: -
- * Find Longest Alternating Subsequence
-
- * A sequence {x1, x2, .. xn} is alternating sequence if its elements satisfy one of the following
- relations :
-
-   x1 < x2 > x3 < x4 > x5 < …. xn or
-   x1 > x2 < x3 > x4 < x5 > …. xn
+/**
+ * Class for finding the length of the longest alternating subsequence in an array.
+ *
+ * <p>An alternating sequence is a sequence of numbers where the elements alternate
+ * between increasing and decreasing. Specifically, a sequence is alternating if its elements
+ * satisfy one of the following relations:
+ *
+ * <ul>
+ *   <li>{@code x1 < x2 > x3 < x4 > x5 < ... < xn}</li>
+ *   <li>{@code x1 > x2 < x3 > x4 < x5 > ... > xn}</li>
+ * </ul>
+ *
+ * <p>This class provides a method to compute the length of the longest such subsequence
+ * from a given array of integers.
  */
 public final class LongestAlternatingSubsequence {
     private LongestAlternatingSubsequence() {
     }
 
-    /* Function to return longest alternating subsequence length*/
+    /**
+     * Finds the length of the longest alternating subsequence in the given array.
+     *
+     * @param arr an array of integers where the longest alternating subsequence is to be found
+     * @param n the length of the array {@code arr}
+     * @return the length of the longest alternating subsequence
+     *
+     * <p>The method uses dynamic programming to solve the problem. It maintains a 2D array
+     * {@code las} where:
+     * <ul>
+     *   <li>{@code las[i][0]} represents the length of the longest alternating subsequence
+     *   ending at index {@code i} with the last element being greater than the previous element.</li>
+     *   <li>{@code las[i][1]} represents the length of the longest alternating subsequence
+     *   ending at index {@code i} with the last element being smaller than the previous element.</li>
+     * </ul>
+     *
+     * <p>The method iterates through the array and updates the {@code las} array based on
+     * whether the current element is greater or smaller than the previous elements.
+     * The result is the maximum value found in the {@code las} array.
+     */
     static int alternatingLength(int[] arr, int n) {
-        /*
-
-                las[i][0] = Length of the longest
-                        alternating subsequence ending at
-                        index i and last element is
-                        greater than its previous element
-
-                las[i][1] = Length of the longest
-                        alternating subsequence ending at
-                        index i and last element is
-                        smaller than its previous
-                        element
-
-         */
         int[][] las = new int[n][2]; // las = LongestAlternatingSubsequence
 
+        // Initialize the dp array
         for (int i = 0; i < n; i++) {
             las[i][0] = 1;
             las[i][1] = 1;
@@ -40,34 +50,24 @@ static int alternatingLength(int[] arr, int n) {
 
         int result = 1; // Initialize result
 
-        /* Compute values in bottom up manner */
+        // Compute values in a bottom-up manner
         for (int i = 1; i < n; i++) {
-            /* Consider all elements as previous of arr[i]*/
             for (int j = 0; j < i; j++) {
-                /* If arr[i] is greater, then check with las[j][1] */
+                // If arr[i] is greater than arr[j], update las[i][0]
                 if (arr[j] < arr[i] && las[i][0] < las[j][1] + 1) {
                     las[i][0] = las[j][1] + 1;
                 }
 
-                /* If arr[i] is smaller, then check with las[j][0]*/
+                // If arr[i] is smaller than arr[j], update las[i][1]
                 if (arr[j] > arr[i] && las[i][1] < las[j][0] + 1) {
                     las[i][1] = las[j][0] + 1;
                 }
             }
 
-            /* Pick maximum of both values at index i */
-            if (result < Math.max(las[i][0], las[i][1])) {
-                result = Math.max(las[i][0], las[i][1]);
-            }
+            // Pick the maximum of both values at index i
+            result = Math.max(result, Math.max(las[i][0], las[i][1]));
         }
 
         return result;
     }
-
-    public static void main(String[] args) {
-        int[] arr = {10, 22, 9, 33, 49, 50, 31, 60};
-        int n = arr.length;
-        System.out.println("Length of Longest "
-            + "alternating subsequence is " + alternatingLength(arr, n));
-    }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java
new file mode 100644
index 000000000000..3de1114a0987
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class LongestAlternatingSubsequenceTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testAlternatingLength(int[] arr, int expected) {
+        assertEquals(expected, LongestAlternatingSubsequence.alternatingLength(arr, arr.length));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new int[] {1}, 1), Arguments.of(new int[] {1, 2}, 2), Arguments.of(new int[] {2, 1}, 2), Arguments.of(new int[] {1, 3, 2, 4, 3, 5}, 6), Arguments.of(new int[] {1, 2, 3, 4, 5}, 2), Arguments.of(new int[] {5, 4, 3, 2, 1}, 2),
+            Arguments.of(new int[] {10, 22, 9, 33, 49, 50, 31, 60}, 6), Arguments.of(new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, 2));
+    }
+}

From cdb64126010bd0ae39277c8e4d1ef8477cc68fd7 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 08:45:07 +0200
Subject: [PATCH 0334/1338] refactor: `LineSweep` (#5398)

---
 .../com/thealgorithms/others/LineSweep.java   | 53 +++++++++++--------
 .../thealgorithms/others/LineSweepTest.java   | 45 +++++++++-------
 2 files changed, 56 insertions(+), 42 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/LineSweep.java b/src/main/java/com/thealgorithms/others/LineSweep.java
index 946ba6edb475..b7db964c98d0 100644
--- a/src/main/java/com/thealgorithms/others/LineSweep.java
+++ b/src/main/java/com/thealgorithms/others/LineSweep.java
@@ -1,42 +1,49 @@
 package com.thealgorithms.others;
+
 import java.util.Arrays;
 import java.util.Comparator;
 
-/* Line Sweep algorithm can be used to solve range problems by first sorting the list of ranges
- * by the start value of the range in non-decreasing order and doing a "sweep" through the number
- * line(x-axis) by incrementing the start point by 1 and decrementing the end point+1 by 1 on the
- * number line.
- * An overlapping range is defined as (StartA <= EndB) AND (EndA >= StartB)
- * References
- * https://en.wikipedia.org/wiki/Sweep_line_algorithm
- * https://en.wikipedia.org/wiki/De_Morgan%27s_laws>
+/**
+ * The Line Sweep algorithm is used to solve range problems efficiently. It works by:
+ * 1. Sorting a list of ranges by their start values in non-decreasing order.
+ * 2. Sweeping through the number line (x-axis) while updating a count for each point based on the ranges.
+ *
+ * An overlapping range is defined as:
+ * - (StartA <= EndB) AND (EndA >= StartB)
+ *
+ * References:
+ * - https://en.wikipedia.org/wiki/Sweep_line_algorithm
+ * - https://en.wikipedia.org/wiki/De_Morgan%27s_laws
  */
 public final class LineSweep {
     private LineSweep() {
     }
 
     /**
-     * Find Maximum end point
-     *   param = ranges : Array of range[start,end]
-     *   return Maximum Endpoint
+     * Finds the maximum endpoint from a list of ranges.
+     *
+     * @param ranges a 2D array where each element is a range represented by [start, end]
+     * @return the maximum endpoint among all ranges
      */
     public static int findMaximumEndPoint(int[][] ranges) {
-        Arrays.sort(ranges, Comparator.comparingInt(a -> a[1]));
+        Arrays.sort(ranges, Comparator.comparingInt(range -> range[1]));
         return ranges[ranges.length - 1][1];
     }
 
     /**
-     * Find if any ranges overlap
-     *   param = ranges : Array of range[start,end]
-     *   return true if overlap exists false otherwise.
+     * Determines if any of the given ranges overlap.
+     *
+     * @param ranges a 2D array where each element is a range represented by [start, end]
+     * @return true if any ranges overlap, false otherwise
      */
     public static boolean isOverlap(int[][] ranges) {
+        if (ranges == null || ranges.length == 0) {
+            return false;
+        }
 
         int maximumEndPoint = findMaximumEndPoint(ranges);
-        Arrays.sort(ranges, Comparator.comparingInt(a -> a[0]));
         int[] numberLine = new int[maximumEndPoint + 2];
         for (int[] range : ranges) {
-
             int start = range[0];
             int end = range[1];
 
@@ -44,12 +51,12 @@ public static boolean isOverlap(int[][] ranges) {
             numberLine[end + 1] -= 1;
         }
 
-        int current = 0;
-        int overlaps = 0;
-        for (int num : numberLine) {
-            current += num;
-            overlaps = Math.max(overlaps, current);
+        int currentCount = 0;
+        int maxOverlaps = 0;
+        for (int count : numberLine) {
+            currentCount += count;
+            maxOverlaps = Math.max(maxOverlaps, currentCount);
         }
-        return overlaps > 1;
+        return maxOverlaps > 1;
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/LineSweepTest.java b/src/test/java/com/thealgorithms/others/LineSweepTest.java
index 6bf6ef5b3002..59fd0fafb068 100644
--- a/src/test/java/com/thealgorithms/others/LineSweepTest.java
+++ b/src/test/java/com/thealgorithms/others/LineSweepTest.java
@@ -1,30 +1,37 @@
 package com.thealgorithms.others;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
 public class LineSweepTest {
+    private record OverlapTestCase(int[][] ranges, boolean expected) {
+    }
 
-    @Test
-    void testForOverlap() {
-        int[][] arr = {{0, 10}, {7, 20}, {15, 24}};
-        assertTrue(LineSweep.isOverlap(arr));
+    private record MaximumEndPointTestCase(int[][] ranges, int expected) {
     }
 
-    @Test
-    void testForNoOverlap() {
-        int[][] arr = {{0, 10}, {11, 20}, {21, 24}};
-        assertFalse(LineSweep.isOverlap(arr));
+    @ParameterizedTest
+    @MethodSource("provideOverlapTestData")
+    void testIsOverlap(OverlapTestCase testCase) {
+        assertEquals(testCase.expected(), LineSweep.isOverlap(testCase.ranges()));
     }
-    @Test
-    void testForOverlapWhenEndAEqualsStartBAndViceVersa() {
-        int[][] arr = {{0, 10}, {10, 20}, {21, 24}};
-        assertTrue(LineSweep.isOverlap(arr));
+
+    private static Stream<Arguments> provideOverlapTestData() {
+        return Stream.of(Arguments.of(new OverlapTestCase(new int[][] {{0, 10}, {7, 20}, {15, 24}}, true)), Arguments.of(new OverlapTestCase(new int[][] {{0, 10}, {11, 20}, {21, 24}}, false)), Arguments.of(new OverlapTestCase(new int[][] {{0, 10}, {10, 20}, {21, 24}}, true)),
+            Arguments.of(new OverlapTestCase(new int[][] {{5, 10}}, false)), Arguments.of(new OverlapTestCase(new int[][] {{1, 5}, {1, 5}, {1, 5}}, true)), Arguments.of(new OverlapTestCase(new int[][] {{1, 1}, {2, 2}, {3, 3}}, false)), Arguments.of(new OverlapTestCase(new int[][] {}, false)));
     }
-    @Test
-    void testForMaximumEndPoint() {
-        int[][] arr = {{10, 20}, {1, 100}, {14, 16}, {1, 8}};
-        assertEquals(100, LineSweep.findMaximumEndPoint(arr));
+
+    @ParameterizedTest
+    @MethodSource("provideMaximumEndPointTestData")
+    void testFindMaximumEndPoint(MaximumEndPointTestCase testCase) {
+        assertEquals(testCase.expected(), LineSweep.findMaximumEndPoint(testCase.ranges()));
+    }
+
+    private static Stream<Arguments> provideMaximumEndPointTestData() {
+        return Stream.of(Arguments.of(new MaximumEndPointTestCase(new int[][] {{10, 20}, {1, 100}, {14, 16}, {1, 8}}, 100)));
     }
 }

From be6b0d835b8bf33545706a0f6dc5f5d3d774411d Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 08:48:30 +0200
Subject: [PATCH 0335/1338] test: `EditDistanceTest` (#5397)

---
 .../dynamicprogramming/EditDistance.java          | 15 ---------------
 .../dynamicprogramming/EditDistanceTest.java      | 15 +++++++++++++++
 2 files changed, 15 insertions(+), 15 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java b/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
index 55ce50d30ea4..020d15197b28 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java
@@ -1,6 +1,5 @@
 package com.thealgorithms.dynamicprogramming;
 
-import java.util.Scanner;
 /**
  * A DynamicProgramming based solution for Edit Distance problem In Java
  * Description of Edit Distance with an Example:
@@ -68,20 +67,6 @@ then take the minimum of the various operations(i.e insertion,removal,substituti
         return dp[len1][len2];
     }
 
-    public static void main(String[] args) {
-        Scanner input = new Scanner(System.in);
-        String s1;
-        String s2;
-        System.out.println("Enter the First String");
-        s1 = input.nextLine();
-        System.out.println("Enter the Second String");
-        s2 = input.nextLine();
-        // ans stores the final Edit Distance between the two strings
-        int ans = minDistance(s1, s2);
-        System.out.println("The minimum Edit Distance between \"" + s1 + "\" and \"" + s2 + "\" is " + ans);
-        input.close();
-    }
-
     // edit distance problem
     public static int editDistance(String s1, String s2) {
         int[][] storage = new int[s1.length() + 1][s2.length() + 1];
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java
new file mode 100644
index 000000000000..267be9b056de
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java
@@ -0,0 +1,15 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class EditDistanceTest {
+
+    @ParameterizedTest
+    @CsvSource({"'', '', 0", "'abc', '', 3", "'', 'abcd', 4", "'same', 'same', 0", "'a', 'b', 1", "'abc', 'abd', 1"})
+    void testMinDistance(String str1, String str2, int expected) {
+        assertEquals(expected, EditDistance.minDistance(str1, str2));
+    }
+}

From 5f6510f0fa20bbf046fb0d9acd02673f10ecaa68 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 08:55:50 +0200
Subject: [PATCH 0336/1338] refactor: `CharactersSame` (#5396)

---
 .../thealgorithms/strings/CharactersSame.java | 24 ++++++---------
 .../strings/CharacterSameTest.java            | 29 +++++--------------
 2 files changed, 17 insertions(+), 36 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/CharactersSame.java b/src/main/java/com/thealgorithms/strings/CharactersSame.java
index 78ccbbea4898..68785052e0e1 100644
--- a/src/main/java/com/thealgorithms/strings/CharactersSame.java
+++ b/src/main/java/com/thealgorithms/strings/CharactersSame.java
@@ -5,25 +5,19 @@ private CharactersSame() {
     }
 
     /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        assert isAllCharactersSame("");
-        assert !isAllCharactersSame("aab");
-        assert isAllCharactersSame("aaa");
-        assert isAllCharactersSame("11111");
-    }
-
-    /**
-     * check if all the characters of a string are same
+     * Checks if all characters in the string are the same.
      *
      * @param s the string to check
-     * @return {@code true} if all characters of a string are same, otherwise
-     * {@code false}
+     * @return {@code true} if all characters in the string are the same or if the string is empty, otherwise {@code false}
      */
     public static boolean isAllCharactersSame(String s) {
-        for (int i = 1, length = s.length(); i < length; ++i) {
-            if (s.charAt(i) != s.charAt(0)) {
+        if (s.isEmpty()) {
+            return true; // Empty strings can be considered as having "all the same characters"
+        }
+
+        char firstChar = s.charAt(0);
+        for (int i = 1; i < s.length(); i++) {
+            if (s.charAt(i) != firstChar) {
                 return false;
             }
         }
diff --git a/src/test/java/com/thealgorithms/strings/CharacterSameTest.java b/src/test/java/com/thealgorithms/strings/CharacterSameTest.java
index d91b5f2f55e9..98f822c4d345 100644
--- a/src/test/java/com/thealgorithms/strings/CharacterSameTest.java
+++ b/src/test/java/com/thealgorithms/strings/CharacterSameTest.java
@@ -1,28 +1,15 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
-public class CharacterSameTest {
+class CharactersSameTest {
 
-    @Test
-    public void isAllCharactersSame() {
-        String input1 = "aaa";
-        String input2 = "abc";
-        String input3 = "1  1  1  1";
-        String input4 = "111";
-        String input5 = "";
-        String input6 = "           ";
-        String input7 = ".       ";
-
-        assertTrue(CharactersSame.isAllCharactersSame(input1));
-        assertFalse(CharactersSame.isAllCharactersSame(input2));
-        assertFalse(CharactersSame.isAllCharactersSame(input3));
-        assertTrue(CharactersSame.isAllCharactersSame(input4));
-        assertTrue(CharactersSame.isAllCharactersSame(input5));
-        assertTrue(CharactersSame.isAllCharactersSame(input6));
-        assertFalse(CharactersSame.isAllCharactersSame(input7));
+    @ParameterizedTest
+    @CsvSource({"aaa, true", "abc, false", "'1  1  1  1', false", "111, true", "'', true", "'           ', true", "'.       ', false", "'a', true", "'  ', true", "'ab', false", "'11111', true", "'ababab', false", "'       ', true", "'+++', true"})
+    void testIsAllCharactersSame(String input, boolean expected) {
+        assertEquals(CharactersSame.isAllCharactersSame(input), expected);
     }
 }

From 35f23d2ddc26a163e9ec645fc5146c1bab3d24b1 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 09:33:24 +0200
Subject: [PATCH 0337/1338] refactor: `BoyerMoore` (#5395)

---
 .../com/thealgorithms/others/BoyerMoore.java  | 75 +++++++++++++------
 .../thealgorithms/others/BoyerMooreTest.java  |  4 +-
 2 files changed, 53 insertions(+), 26 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/BoyerMoore.java b/src/main/java/com/thealgorithms/others/BoyerMoore.java
index e67427deda79..3fb97724b5ac 100644
--- a/src/main/java/com/thealgorithms/others/BoyerMoore.java
+++ b/src/main/java/com/thealgorithms/others/BoyerMoore.java
@@ -1,54 +1,81 @@
-/* this Code is the illustration of Boyer moore's voting algorithm to
-find the majority element is an array that appears more than n/2 times in an array
-where "n" is the length of the array.
-For more information on the algorithm refer
-https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_majority_vote_algorithm
- */
 package com.thealgorithms.others;
 import java.util.Optional;
 
+/**
+ * Utility class implementing Boyer-Moore's Voting Algorithm to find the majority element
+ * in an array. The majority element is defined as the element that appears more than n/2 times
+ * in the array, where n is the length of the array.
+ *
+ * For more information on the algorithm, refer to:
+ * https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_majority_vote_algorithm
+ */
 public final class BoyerMoore {
     private BoyerMoore() {
     }
 
-    public static Optional<Integer> findMajor(final int[] a) {
-        final var candidate = findCandidate(a);
-        final var count = countOccurrences(candidate, a);
-        if (isMajority(count, a.length)) {
+    /**
+     * Finds the majority element in the given array if it exists.
+     *
+     * @param array the input array
+     * @return an Optional containing the majority element if it exists, otherwise an empty Optional
+     */
+    public static Optional<Integer> findMajorityElement(int[] array) {
+        if (array == null || array.length == 0) {
+            return Optional.empty();
+        }
+
+        int candidate = findCandidate(array);
+        int count = countOccurrences(candidate, array);
+
+        if (isMajority(count, array.length)) {
             return Optional.of(candidate);
         }
         return Optional.empty();
     }
 
-    private static int findCandidate(final int[] a) {
+    /**
+     * Identifies the potential majority candidate using Boyer-Moore's Voting Algorithm.
+     *
+     * @param array the input array
+     * @return the candidate for the majority element
+     */
+    private static int findCandidate(final int[] array) {
         int count = 0;
         int candidate = -1;
-        for (final var k : a) {
+        for (int value : array) {
             if (count == 0) {
-                candidate = k;
-                count = 1;
-            } else {
-                if (k == candidate) {
-                    count++;
-                } else {
-                    count--;
-                }
+                candidate = value;
             }
+            count += (value == candidate) ? 1 : -1;
         }
         return candidate;
     }
 
-    private static int countOccurrences(final int candidate, final int[] a) {
+    /**
+     * Counts the occurrences of the candidate element in the array.
+     *
+     * @param candidate the candidate element
+     * @param array the input array
+     * @return the number of times the candidate appears in the array
+     */
+    private static int countOccurrences(final int candidate, final int[] array) {
         int count = 0;
-        for (final var j : a) {
-            if (j == candidate) {
+        for (int value : array) {
+            if (value == candidate) {
                 count++;
             }
         }
         return count;
     }
 
-    private static boolean isMajority(final int count, final int totalCount) {
+    /**
+     * Determines if the count of the candidate element is more than n/2, where n is the length of the array.
+     *
+     * @param count the number of occurrences of the candidate
+     * @param totalCount the total number of elements in the array
+     * @return true if the candidate is the majority element, false otherwise
+     */
+    private static boolean isMajority(int count, int totalCount) {
         return 2 * count > totalCount;
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/BoyerMooreTest.java b/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
index b6620793d267..8416535b2111 100644
--- a/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
+++ b/src/test/java/com/thealgorithms/others/BoyerMooreTest.java
@@ -11,7 +11,7 @@ public class BoyerMooreTest {
     @ParameterizedTest
     @MethodSource("inputStreamWithExistingMajority")
     void checkWhenMajorityExists(int expected, int[] input) {
-        Assertions.assertEquals(expected, BoyerMoore.findMajor(input).get());
+        Assertions.assertEquals(expected, BoyerMoore.findMajorityElement(input).get());
     }
 
     private static Stream<Arguments> inputStreamWithExistingMajority() {
@@ -21,7 +21,7 @@ private static Stream<Arguments> inputStreamWithExistingMajority() {
     @ParameterizedTest
     @MethodSource("inputStreamWithoutMajority")
     void checkWhenMajorityExists(int[] input) {
-        Assertions.assertFalse(BoyerMoore.findMajor(input).isPresent());
+        Assertions.assertFalse(BoyerMoore.findMajorityElement(input).isPresent());
     }
 
     private static Stream<Arguments> inputStreamWithoutMajority() {

From b70f077343a4629cf163400f1d64993c6ab2bbf7 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 10:50:12 +0200
Subject: [PATCH 0338/1338] refactor: `ShortestCommonSuperSequenceLength`
 (#5394)

---
 .../ShortestCommonSupersequenceLength.java    | 45 ++++++++++++-------
 ...ShortestCommonSuperSequenceLengthTest.java | 14 ++++++
 2 files changed, 42 insertions(+), 17 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSuperSequenceLengthTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java b/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
index 362ed5e252d2..3ea440caf508 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
@@ -1,12 +1,23 @@
 package com.thealgorithms.dynamicprogramming;
 
-// Java program to find length of the shortest supersequence
-final class ShortestSuperSequence {
-    private ShortestSuperSequence() {
+/**
+ * Class that provides methods to calculate the length of the shortest
+ * supersequence of two given strings. The shortest supersequence is the smallest string
+ * that contains both given strings as subsequences.
+ */
+final class ShortestCommonSuperSequenceLength {
+    private ShortestCommonSuperSequenceLength() {
     }
 
-    // Function to find length of the
-    // shortest supersequence of x and y.
+    /**
+     * Finds the length of the shortest supersequence of two given strings.
+     * The shortest supersequence is defined as the smallest string that contains both
+     * given strings as subsequences.
+     *
+     * @param x The first input string.
+     * @param y The second input string.
+     * @return The length of the shortest supersequence of the two strings.
+     */
     static int shortestSuperSequence(String x, String y) {
         int m = x.length();
         int n = y.length();
@@ -16,11 +27,20 @@ static int shortestSuperSequence(String x, String y) {
 
         // Result is sum of input string
         // lengths - length of lcs
-        return (m + n - l);
+        return m + n - l;
     }
 
-    // Returns length of LCS
-    // for x[0..m - 1], y[0..n - 1]
+    /**
+     * Calculates the length of the longest common subsequence (LCS) between two strings.
+     * The LCS is the longest sequence that can be derived from both strings by deleting some
+     * (or none) of the characters without changing the order of the remaining characters.
+     *
+     * @param x The first input string.
+     * @param y The second input string.
+     * @param m The length of the first input string.
+     * @param n The length of the second input string.
+     * @return The length of the longest common subsequence of the two strings.
+     */
     static int lcs(String x, String y, int m, int n) {
         int[][] lN = new int[m + 1][n + 1];
         int i;
@@ -46,13 +66,4 @@ static int lcs(String x, String y, int m, int n) {
         // for x[0..n - 1] and y[0..m - 1]
         return lN[m][n];
     }
-
-    // Driver code
-    public static void main(String[] args) {
-        String x = "AGGTAB";
-        String y = "GXTXAYB";
-
-        System.out.println("Length of the shortest "
-            + "supersequence is " + shortestSuperSequence(x, y));
-    }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSuperSequenceLengthTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSuperSequenceLengthTest.java
new file mode 100644
index 000000000000..007e71e268ab
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSuperSequenceLengthTest.java
@@ -0,0 +1,14 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class ShortestCommonSuperSequenceLengthTest {
+    @ParameterizedTest
+    @CsvSource({"AGGTAB, GXTXAYB, 9", "ABC, ABC, 3", "ABC, DEF, 6", "'', ABC, 3", "ABCD, AB, 4", "ABC, BCD, 4", "A, B, 2"})
+    void testShortestSuperSequence(String input1, String input2, int expected) {
+        assertEquals(expected, ShortestCommonSuperSequenceLength.shortestSuperSequence(input1, input2));
+    }
+}

From 64ff9b2efe0533027139a14ea8f66e63f483e541 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 15:38:33 +0200
Subject: [PATCH 0339/1338] refactor: `StackPostfixNotation` (#5400)

---
 .../stacks/StackPostfixNotation.java          | 13 ++++--
 .../stacks/StackPostfixNotationTest.java      | 43 +++++++------------
 2 files changed, 26 insertions(+), 30 deletions(-)

diff --git a/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java b/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java
index d4b7c9222e1d..690f39d36f5c 100644
--- a/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java
+++ b/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java
@@ -5,8 +5,15 @@
 import java.util.function.BiFunction;
 
 /**
- * @brief Utility class evaluating postix expressions, cf. https://en.wikipedia.org/wiki/Reverse_Polish_notation
- * @details The computation is done using Integers.
+ * Utility class for evaluating postfix expressions using integer arithmetic.
+ * <p>
+ * Postfix notation, also known as Reverse Polish Notation (RPN), is a mathematical notation in which operators follow their operands.
+ * This class provides a method to evaluate expressions written in postfix notation.
+ * </p>
+ * <p>
+ * For more information on postfix notation, refer to
+ * <a href="https://en.wikipedia.org/wiki/Reverse_Polish_notation">Reverse Polish Notation (RPN) on Wikipedia</a>.
+ * </p>
  */
 public final class StackPostfixNotation {
     private StackPostfixNotation() {
@@ -55,7 +62,7 @@ private static void consumeExpression(Stack<Integer> s, final String exp) {
      * @exception IllegalArgumentException exp is not a valid postix expression.
      */
     public static int postfixEvaluate(final String exp) {
-        Stack<Integer> s = new Stack<Integer>();
+        Stack<Integer> s = new Stack<>();
         consumeExpression(s, exp);
         if (s.size() != 1) {
             throw new IllegalArgumentException("exp is not a proper postfix expression.");
diff --git a/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java b/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java
index a8d8e0d3d9dc..97424a8f291d 100644
--- a/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java
+++ b/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java
@@ -1,43 +1,32 @@
 package com.thealgorithms.stacks;
 
-import static java.util.Map.entry;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import java.util.Map;
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class StackPostfixNotationTest {
-    @Test
-    public void testEvaluate() {
-        final Map<String, Integer> testCases = Map.ofEntries(entry("1 1 +", 2), entry("2 3 *", 6), entry("6 2 /", 3), entry("-5 -2 -", -3), entry("5 2 + 3 *", 21), entry("-5", -5));
-        for (final var tc : testCases.entrySet()) {
-            assertEquals(tc.getValue(), StackPostfixNotation.postfixEvaluate(tc.getKey()));
-        }
-    }
-
-    @Test
-    public void testIfEvaluateThrowsExceptionForEmptyInput() {
-        assertThrows(IllegalArgumentException.class, () -> StackPostfixNotation.postfixEvaluate(""));
-    }
 
-    @Test
-    public void testIfEvaluateThrowsExceptionForInproperInput() {
-        assertThrows(IllegalArgumentException.class, () -> StackPostfixNotation.postfixEvaluate("3 3 3"));
+    @ParameterizedTest
+    @MethodSource("provideValidTestCases")
+    void testEvaluate(String expression, int expected) {
+        assertEquals(expected, StackPostfixNotation.postfixEvaluate(expression));
     }
 
-    @Test
-    public void testIfEvaluateThrowsExceptionForInputWithUnknownOperation() {
-        assertThrows(IllegalArgumentException.class, () -> StackPostfixNotation.postfixEvaluate("3 3 !"));
+    static Stream<Arguments> provideValidTestCases() {
+        return Stream.of(Arguments.of("1 1 +", 2), Arguments.of("2 3 *", 6), Arguments.of("6 2 /", 3), Arguments.of("-5 -2 -", -3), Arguments.of("5 2 + 3 *", 21), Arguments.of("-5", -5));
     }
 
-    @Test
-    public void testIfEvaluateThrowsExceptionForInputWithTooFewArgsA() {
-        assertThrows(IllegalArgumentException.class, () -> StackPostfixNotation.postfixEvaluate("+"));
+    @ParameterizedTest
+    @MethodSource("provideInvalidTestCases")
+    void testEvaluateThrowsException(String expression) {
+        assertThrows(IllegalArgumentException.class, () -> StackPostfixNotation.postfixEvaluate(expression));
     }
 
-    @Test
-    public void testIfEvaluateThrowsExceptionForInputWithTooFewArgsB() {
-        assertThrows(IllegalArgumentException.class, () -> StackPostfixNotation.postfixEvaluate("2 +"));
+    static Stream<Arguments> provideInvalidTestCases() {
+        return Stream.of(Arguments.of(""), Arguments.of("3 3 3"), Arguments.of("3 3 !"), Arguments.of("+"), Arguments.of("2 +"));
     }
 }

From 4347f5b9f6691f71972e5507a4c8c7c56234ffe0 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 15:43:13 +0200
Subject: [PATCH 0340/1338] refactor: `InfixToPostfix` (#5401)

---
 .../thealgorithms/stacks/InfixToPostfix.java  | 16 +++++----
 .../stacks/InfixToPostfixTest.java            | 33 +++++++++++++++++++
 2 files changed, 42 insertions(+), 7 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java b/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java
index e3519978c6e5..33611bd73dba 100644
--- a/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java
+++ b/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java
@@ -1,19 +1,15 @@
 package com.thealgorithms.stacks;
 
 import java.util.Stack;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 public final class InfixToPostfix {
     private InfixToPostfix() {
     }
 
-    public static void main(String[] args) throws Exception {
-        assert "32+".equals(infix2PostFix("3+2"));
-        assert "123++".equals(infix2PostFix("1+(2+3)"));
-        assert "34+5*6-".equals(infix2PostFix("(3+4)*5-6"));
-    }
-
     public static String infix2PostFix(String infixExpression) throws Exception {
-        if (!BalancedBrackets.isBalanced(infixExpression)) {
+        if (!BalancedBrackets.isBalanced(filterBrackets(infixExpression))) {
             throw new Exception("invalid expression");
         }
         StringBuilder output = new StringBuilder();
@@ -55,4 +51,10 @@ private static int precedence(char operator) {
             return -1;
         }
     }
+
+    private static String filterBrackets(String input) {
+        Pattern pattern = Pattern.compile("[^(){}\\[\\]<>]");
+        Matcher matcher = pattern.matcher(input);
+        return matcher.replaceAll("");
+    }
 }
diff --git a/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java b/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java
new file mode 100644
index 000000000000..02a08e393a00
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class InfixToPostfixTest {
+
+    @ParameterizedTest
+    @MethodSource("provideValidExpressions")
+    void testValidExpressions(String infix, String expectedPostfix) throws Exception {
+        assertEquals(expectedPostfix, InfixToPostfix.infix2PostFix(infix));
+    }
+
+    private static Stream<Arguments> provideValidExpressions() {
+        return Stream.of(Arguments.of("3+2", "32+"), Arguments.of("1+(2+3)", "123++"), Arguments.of("(3+4)*5-6", "34+5*6-"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideInvalidExpressions")
+    void testInvalidExpressions(String infix, String expectedMessage) {
+        Exception exception = assertThrows(Exception.class, () -> InfixToPostfix.infix2PostFix(infix));
+        assertEquals(expectedMessage, exception.getMessage());
+    }
+
+    private static Stream<Arguments> provideInvalidExpressions() {
+        return Stream.of(Arguments.of("((a+b)*c-d", "invalid expression"));
+    }
+}

From 4374a50fd74be1fa866071d9ca26ffbc6e63011b Mon Sep 17 00:00:00 2001
From: Andrii Siriak <siryaka@gmail.com>
Date: Mon, 26 Aug 2024 17:06:41 +0300
Subject: [PATCH 0341/1338] Update CODEOWNERS

---
 .github/CODEOWNERS | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 4f36c32c5157..0a19890aed44 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1 +1 @@
-* @yanglbme @vil02 @BamaCharanChhandogi @alxkm
+* @yanglbme @vil02 @BamaCharanChhandogi @alxkm @siriak

From 7674a84f5b6670fbb306aafdb8176ba5dffc2a36 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 16:22:39 +0200
Subject: [PATCH 0342/1338] test: `RegexMatchingTest` (#5403)

* test: RegexMatchingTest

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
Co-authored-by: Andrii Siriak <siryaka@gmail.com>
---
 .../dynamicprogramming/RegexMatching.java     | 79 +++++++++++++------
 .../dynamicprogramming/RegexMatchingTest.java | 43 ++++++++++
 2 files changed, 99 insertions(+), 23 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/RegexMatchingTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java b/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java
index c07563ad0020..181ac72a654d 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java
@@ -6,17 +6,28 @@
  * cover the entire text ?-> matches single characters *-> match the sequence of
  * characters
  *
- * For calculation of Time and Space Complexity. Let N be length of src and M be
- * length of pat
+ * For calculation of Time and Space Complexity. Let N be length of src and M be length of pat
  *
+ * Memoization vs Tabulation : https://www.geeksforgeeks.org/tabulation-vs-memoization/
+ * Question Link : https://practice.geeksforgeeks.org/problems/wildcard-pattern-matching/1
  */
 public final class RegexMatching {
     private RegexMatching() {
     }
 
-    // Method 1: Using Recursion
-    // Time Complexity=0(2^(N+M)) Space Complexity=Recursion Extra Space
-    static boolean regexRecursion(String src, String pat) {
+    /**
+     * Method 1: Determines if the given source string matches the given pattern using a recursive approach.
+     * This method directly applies recursion to check if the source string matches the pattern, considering
+     * the wildcards '?' and '*'.
+     *
+     * Time Complexity: O(2^(N+M)), where N is the length of the source string and M is the length of the pattern.
+     * Space Complexity: O(N + M) due to the recursion stack.
+     *
+     * @param src The source string to be matched against the pattern.
+     * @param pat The pattern containing wildcards ('*' matches a sequence of characters, '?' matches a single character).
+     * @return {@code true} if the source string matches the pattern, {@code false} otherwise.
+     */
+    public static boolean regexRecursion(String src, String pat) {
         if (src.length() == 0 && pat.length() == 0) {
             return true;
         }
@@ -50,8 +61,19 @@ static boolean regexRecursion(String src, String pat) {
         return ans;
     }
 
-    // Method 2: Using Recursion and breaking string using virtual index
-    // Time Complexity=0(2^(N+M)) Space Complexity=Recursion Extra Space
+    /**
+     * Method 2: Determines if the given source string matches the given pattern using recursion.
+     * This method utilizes a virtual index for both the source string and the pattern to manage the recursion.
+     *
+     * Time Complexity: O(2^(N+M)) where N is the length of the source string and M is the length of the pattern.
+     * Space Complexity: O(N + M) due to the recursion stack.
+     *
+     * @param src The source string to be matched against the pattern.
+     * @param pat The pattern containing wildcards ('*' matches a sequence of characters, '?' matches a single character).
+     * @param svidx The current index in the source string.
+     * @param pvidx The current index in the pattern.
+     * @return {@code true} if the source string matches the pattern, {@code false} otherwise.
+     */
     static boolean regexRecursion(String src, String pat, int svidx, int pvidx) {
         if (src.length() == svidx && pat.length() == pvidx) {
             return true;
@@ -83,9 +105,21 @@ static boolean regexRecursion(String src, String pat, int svidx, int pvidx) {
         return ans;
     }
 
-    // Method 3: Top-Down DP(Memoization)
-    // Time Complexity=0(N*M) Space Complexity=0(N*M)+Recursion Extra Space
-    static boolean regexRecursion(String src, String pat, int svidx, int pvidx, int[][] strg) {
+    /**
+     * Method 3: Determines if the given source string matches the given pattern using top-down dynamic programming (memoization).
+     * This method utilizes memoization to store intermediate results, reducing redundant computations and improving efficiency.
+     *
+     * Time Complexity: O(N * M), where N is the length of the source string and M is the length of the pattern.
+     * Space Complexity: O(N * M) for the memoization table, plus additional space for the recursion stack.
+     *
+     * @param src The source string to be matched against the pattern.
+     * @param pat The pattern containing wildcards ('*' matches a sequence of characters, '?' matches a single character).
+     * @param svidx The current index in the source string.
+     * @param pvidx The current index in the pattern.
+     * @param strg A 2D array used for memoization to store the results of subproblems.
+     * @return {@code true} if the source string matches the pattern, {@code false} otherwise.
+     */
+    public static boolean regexRecursion(String src, String pat, int svidx, int pvidx, int[][] strg) {
         if (src.length() == svidx && pat.length() == pvidx) {
             return true;
         }
@@ -120,8 +154,18 @@ static boolean regexRecursion(String src, String pat, int svidx, int pvidx, int[
         return ans;
     }
 
-    // Method 4: Bottom-Up DP(Tabulation)
-    // Time Complexity=0(N*M) Space Complexity=0(N*M)
+    /**
+     * Method 4: Determines if the given source string matches the given pattern using bottom-up dynamic programming (tabulation).
+     * This method builds a solution iteratively by filling out a table, where each cell represents whether a substring
+     * of the source string matches a substring of the pattern.
+     *
+     * Time Complexity: O(N * M), where N is the length of the source string and M is the length of the pattern.
+     * Space Complexity: O(N * M) for the table used in the tabulation process.
+     *
+     * @param src The source string to be matched against the pattern.
+     * @param pat The pattern containing wildcards ('*' matches a sequence of characters, '?' matches a single character).
+     * @return {@code true} if the source string matches the pattern, {@code false} otherwise.
+     */
     static boolean regexBU(String src, String pat) {
         boolean[][] strg = new boolean[src.length() + 1][pat.length() + 1];
         strg[src.length()][pat.length()] = true;
@@ -153,15 +197,4 @@ static boolean regexBU(String src, String pat) {
         }
         return strg[0][0];
     }
-
-    public static void main(String[] args) {
-        String src = "aa";
-        String pat = "*";
-        System.out.println("Method 1: " + regexRecursion(src, pat));
-        System.out.println("Method 2: " + regexRecursion(src, pat, 0, 0));
-        System.out.println("Method 3: " + regexRecursion(src, pat, 0, 0, new int[src.length()][pat.length()]));
-        System.out.println("Method 4: " + regexBU(src, pat));
-    }
 }
-// Memoization vs Tabulation : https://www.geeksforgeeks.org/tabulation-vs-memoization/
-// Question Link : https://practice.geeksforgeeks.org/problems/wildcard-pattern-matching/1
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/RegexMatchingTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/RegexMatchingTest.java
new file mode 100644
index 000000000000..e75482a68d8b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/RegexMatchingTest.java
@@ -0,0 +1,43 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class RegexMatchingTest {
+
+    private record RegexTestCase(String s, String p, boolean expected) {
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new RegexTestCase("aa", "*", true)), Arguments.of(new RegexTestCase("aa", "a*", true)), Arguments.of(new RegexTestCase("aa", "a", false)), Arguments.of(new RegexTestCase("cb", "?b", true)), Arguments.of(new RegexTestCase("cb", "?a", false)),
+            Arguments.of(new RegexTestCase("adceb", "*a*b", true)), Arguments.of(new RegexTestCase("acdcb", "a*c?b", false)), Arguments.of(new RegexTestCase("", "*", true)), Arguments.of(new RegexTestCase("", "", true)));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testRegexRecursionMethod1(RegexTestCase testCase) {
+        assertEquals(testCase.expected(), RegexMatching.regexRecursion(testCase.s(), testCase.p()));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testRegexRecursionMethod2(RegexTestCase testCase) {
+        assertEquals(testCase.expected(), RegexMatching.regexRecursion(testCase.s(), testCase.p(), 0, 0));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testRegexRecursionMethod3(RegexTestCase testCase) {
+        assertEquals(testCase.expected(), RegexMatching.regexRecursion(testCase.s(), testCase.p(), 0, 0, new int[testCase.s().length()][testCase.p().length()]));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testRegexBottomUp(RegexTestCase testCase) {
+        assertEquals(testCase.expected(), RegexMatching.regexBU(testCase.s(), testCase.p()));
+    }
+}

From d810a1d4daf08e9721a00939b497749a62c5b5fa Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 16:29:16 +0200
Subject: [PATCH 0343/1338] test: `LongestPalindromicSubstring` (#5402)

* LongestPalindromicSubstring

* fix Rule:CollapsibleIfStatements

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../strings/LongestPalindromicSubstring.java  | 39 +++++++------------
 .../LongestPalindromicSubstringTest.java      | 21 ++++++++++
 2 files changed, 34 insertions(+), 26 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java

diff --git a/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java b/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java
index fa9171133a15..ca500357ba77 100644
--- a/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java
+++ b/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java
@@ -1,44 +1,31 @@
 package com.thealgorithms.strings;
 
-// Longest Palindromic Substring
-import java.util.Scanner;
-
 final class LongestPalindromicSubstring {
     private LongestPalindromicSubstring() {
     }
 
-    public static void main(String[] args) {
-        Solution s = new Solution();
-        String str = "";
-        Scanner sc = new Scanner(System.in);
-        System.out.print("Enter the string: ");
-        str = sc.nextLine();
-        System.out.println("Longest substring is : " + s.longestPalindrome(str));
-        sc.close();
-    }
-}
-
-class Solution {
-
-    public String longestPalindrome(String s) {
-        if (s == null || s.length() == 0) {
+    /**
+     * Finds the longest palindromic substring in the given string.
+     *
+     * @param s the input string
+     * @return the longest palindromic substring
+     */
+    public static String longestPalindrome(String s) {
+        if (s == null || s.isEmpty()) {
             return "";
         }
-        int n = s.length();
         String maxStr = "";
-        for (int i = 0; i < n; ++i) {
-            for (int j = i; j < n; ++j) {
-                if (isValid(s, i, j)) {
-                    if (j - i + 1 > maxStr.length()) { // update maxStr
-                        maxStr = s.substring(i, j + 1);
-                    }
+        for (int i = 0; i < s.length(); ++i) {
+            for (int j = i; j < s.length(); ++j) {
+                if (isValid(s, i, j) && (j - i + 1 > maxStr.length())) {
+                    maxStr = s.substring(i, j + 1);
                 }
             }
         }
         return maxStr;
     }
 
-    private boolean isValid(String s, int lo, int hi) {
+    private static boolean isValid(String s, int lo, int hi) {
         int n = hi - lo + 1;
         for (int i = 0; i < n / 2; ++i) {
             if (s.charAt(lo + i) != s.charAt(hi - i)) {
diff --git a/src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java b/src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java
new file mode 100644
index 000000000000..aa13c0f4a474
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class LongestPalindromicSubstringTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCasesForLongestPalindrome")
+    void testLongestPalindrome(String input, String expected) {
+        assertEquals(expected, LongestPalindromicSubstring.longestPalindrome(input));
+    }
+
+    private static Stream<Arguments> provideTestCasesForLongestPalindrome() {
+        return Stream.of(Arguments.of("babad", "bab"), Arguments.of("cbbd", "bb"), Arguments.of("a", "a"), Arguments.of("", ""), Arguments.of("abc", "a"), Arguments.of(null, ""), Arguments.of("aaaaa", "aaaaa"));
+    }
+}

From c5b73ec742d0522d65331ee02a143f54041845ed Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 26 Aug 2024 16:37:17 +0200
Subject: [PATCH 0344/1338] refactor: `HammingDistance` (#5404)

* refactor: HammingDistance

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../strings/HammingDistance.java              | 39 ++++++++++++-------
 .../strings/HammingDistanceTest.java          | 30 +++++++++-----
 2 files changed, 46 insertions(+), 23 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/HammingDistance.java b/src/main/java/com/thealgorithms/strings/HammingDistance.java
index 95c523ccd411..235e317d94f1 100644
--- a/src/main/java/com/thealgorithms/strings/HammingDistance.java
+++ b/src/main/java/com/thealgorithms/strings/HammingDistance.java
@@ -1,34 +1,45 @@
 package com.thealgorithms.strings;
 
-/* In information theory, the Hamming distance between two strings of equal length
-is the number of positions at which the corresponding symbols are different.
-https://en.wikipedia.org/wiki/Hamming_distance
-*/
+/**
+ * Class for calculating the Hamming distance between two strings of equal length.
+ * <p>
+ * The Hamming distance is the number of positions at which the corresponding symbols are different.
+ * It is used in information theory, coding theory, and computer science.
+ * </p>
+ * @see <a href="https://en.wikipedia.org/wiki/Hamming_distance">Hamming distance - Wikipedia</a>
+ */
 public final class HammingDistance {
     private HammingDistance() {
     }
 
     /**
-     * calculate the hamming distance between two strings of equal length
+     * Calculates the Hamming distance between two strings of equal length.
+     * <p>
+     * The Hamming distance is defined only for strings of equal length. If the strings are not
+     * of equal length, this method throws an {@code IllegalArgumentException}.
+     * </p>
      *
      * @param s1 the first string
      * @param s2 the second string
-     * @return {@code int} hamming distance
-     * @throws Exception
+     * @return the Hamming distance between the two strings
+     * @throws IllegalArgumentException if the lengths of {@code s1} and {@code s2} are not equal
      */
-    public static int calculateHammingDistance(String s1, String s2) throws Exception {
+    public static int calculateHammingDistance(String s1, String s2) {
+        if (s1 == null || s2 == null) {
+            throw new IllegalArgumentException("Strings must not be null");
+        }
+
         if (s1.length() != s2.length()) {
-            throw new Exception("String lengths must be equal");
+            throw new IllegalArgumentException("String lengths must be equal");
         }
 
-        int stringLength = s1.length();
-        int counter = 0;
+        int distance = 0;
 
-        for (int i = 0; i < stringLength; i++) {
+        for (int i = 0; i < s1.length(); i++) {
             if (s1.charAt(i) != s2.charAt(i)) {
-                counter++;
+                distance++;
             }
         }
-        return counter;
+        return distance;
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/HammingDistanceTest.java b/src/test/java/com/thealgorithms/strings/HammingDistanceTest.java
index e0fbdb1442a7..5c0640348404 100644
--- a/src/test/java/com/thealgorithms/strings/HammingDistanceTest.java
+++ b/src/test/java/com/thealgorithms/strings/HammingDistanceTest.java
@@ -3,22 +3,34 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.MethodSource;
 
-public class HammingDistanceTest {
+class HammingDistanceTest {
 
-    @Test
-    void testHammingDistance() throws Exception {
-        assertEquals(HammingDistance.calculateHammingDistance("", ""), 0);
-        assertEquals(HammingDistance.calculateHammingDistance("java", "java"), 0);
-        assertEquals(HammingDistance.calculateHammingDistance("karolin", "kathrin"), 3);
-        assertEquals(HammingDistance.calculateHammingDistance("kathrin", "kerstin"), 4);
-        assertEquals(HammingDistance.calculateHammingDistance("00000", "11111"), 5);
+    @ParameterizedTest
+    @CsvSource({"'', '', 0", "'java', 'java', 0", "'karolin', 'kathrin', 3", "'kathrin', 'kerstin', 4", "'00000', '11111', 5", "'10101', '10100', 1"})
+    void testHammingDistance(String s1, String s2, int expected) {
+        assertEquals(expected, HammingDistance.calculateHammingDistance(s1, s2));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideNullInputs")
+    void testHammingDistanceWithNullInputs(String input1, String input2) {
+        assertThrows(IllegalArgumentException.class, () -> HammingDistance.calculateHammingDistance(input1, input2));
+    }
+
+    private static Stream<Arguments> provideNullInputs() {
+        return Stream.of(Arguments.of(null, "abc"), Arguments.of("abc", null), Arguments.of(null, null));
     }
 
     @Test
     void testNotEqualStringLengths() {
-        Exception exception = assertThrows(Exception.class, () -> HammingDistance.calculateHammingDistance("ab", "abc"));
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> HammingDistance.calculateHammingDistance("ab", "abc"));
         assertEquals("String lengths must be equal", exception.getMessage());
     }
 }

From 6fab70a91f5dba8427c974c4667b5c4a19303318 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 27 Aug 2024 00:01:27 +0200
Subject: [PATCH 0345/1338] Chore(deps): bump com.puppycrawl.tools:checkstyle
 from 10.17.0 to 10.18.0 (#5411)

Chore(deps): bump com.puppycrawl.tools:checkstyle

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.17.0 to 10.18.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.17.0...checkstyle-10.18.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 5854aff4ff1e..18288b8cf805 100644
--- a/pom.xml
+++ b/pom.xml
@@ -118,7 +118,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.17.0</version>
+                    <version>10.18.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From c8cf302d302e1faa78b80799322ec67fa7a2b808 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 27 Aug 2024 10:39:40 +0200
Subject: [PATCH 0346/1338] refactor: `NextGreaterElement` (#5405)

* refactor: NextGreaterElement

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../stacks/NextGreaterElement.java            | 65 ++++++-------------
 .../stacks/NextGreaterElementTest.java        | 29 +++++++++
 2 files changed, 49 insertions(+), 45 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java b/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java
index f7cbea714eb0..8b7c9c3ef9cf 100644
--- a/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java
+++ b/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java
@@ -1,53 +1,34 @@
 package com.thealgorithms.stacks;
 
-import java.util.Arrays;
 import java.util.Stack;
 
-/*
-    Given an array "input" you need to print the first greater element for each element.
-    For a given element x of an array, the Next greater element of that element is the
-    first greater element to the right side of it. If no such element is present print -1.
-
-    Example
-    input = { 2, 7, 3, 5, 4, 6, 8 };
-    At i = 0
-    Next greater element between (1 to n) is 7
-    At i = 1
-    Next greater element between (2 to n) is 8
-    At i = 2
-    Next greater element between (3 to n) is 5
-    At i = 3
-    Next greater element between (4 to n) is 6
-    At i = 4
-    Next greater element between (5 to n) is 6
-    At i = 5
-    Next greater element between (6 to n) is 8
-    At i = 6
-    Next greater element between (6 to n) is -1
-
-    result : [7, 8, 5, 6, 6, 8, -1]
-
-    1. If the stack is empty Push an element in the stack.
-    2. If the stack is not empty:
-        a.  compare the top element of the stack with next.
-        b.  If next is greater than the top element, Pop element from the stack.
-            next is the next greater element for the popped element.
-        c.  Keep popping from the stack while the popped element is smaller
-            than next. next becomes the next greater element for all such
-            popped elements.
-        d. Finally, push the next in the stack.
-
-    3. If elements are left in stack after completing while loop then their Next greater element is
-   -1.
+/**
+ * Utility class to find the next greater element for each element in a given integer array.
+ *
+ * <p>The next greater element for an element x is the first greater element on the right side of x in the array.
+ * If no such element exists, the result will contain 0 for that position.</p>
+ *
+ * <p>Example:</p>
+ * <pre>
+ * Input:  {2, 7, 3, 5, 4, 6, 8}
+ * Output: {7, 0, 5, 6, 6, 8, 0}
+ * </pre>
  */
-
 public final class NextGreaterElement {
     private NextGreaterElement() {
     }
 
+    /**
+     * Finds the next greater element for each element in the given array.
+     *
+     * @param array the input array of integers
+     * @return an array where each element is replaced by the next greater element on the right side in the input array,
+     * or 0 if there is no greater element.
+     * @throws IllegalArgumentException if the input array is null
+     */
     public static int[] findNextGreaterElements(int[] array) {
         if (array == null) {
-            return array;
+            throw new IllegalArgumentException("Input array cannot be null");
         }
 
         int[] result = new int[array.length];
@@ -62,10 +43,4 @@ public static int[] findNextGreaterElements(int[] array) {
 
         return result;
     }
-
-    public static void main(String[] args) {
-        int[] input = {2, 7, 3, 5, 4, 6, 8};
-        int[] result = findNextGreaterElements(input);
-        System.out.println(Arrays.toString(result));
-    }
 }
diff --git a/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java b/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java
new file mode 100644
index 000000000000..bf015ddc9996
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class NextGreaterElementTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testFindNextGreaterElements(int[] input, int[] expected) {
+        assertArrayEquals(expected, NextGreaterElement.findNextGreaterElements(input));
+    }
+
+    static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new int[] {2, 7, 3, 5, 4, 6, 8}, new int[] {7, 8, 5, 6, 6, 8, 0}), Arguments.of(new int[] {5}, new int[] {0}), Arguments.of(new int[] {1, 2, 3, 4, 5}, new int[] {2, 3, 4, 5, 0}), Arguments.of(new int[] {5, 4, 3, 2, 1}, new int[] {0, 0, 0, 0, 0}),
+            Arguments.of(new int[] {4, 5, 2, 25}, new int[] {5, 25, 25, 0}), Arguments.of(new int[] {}, new int[] {}));
+    }
+
+    @Test
+    void testNullInput() {
+        assertThrows(IllegalArgumentException.class, () -> NextGreaterElement.findNextGreaterElements(null));
+    }
+}

From 0c8616e33226ed87fcb5a78c4b4b30c336bd0057 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 27 Aug 2024 10:49:20 +0200
Subject: [PATCH 0347/1338] test: `ReverseStringRecursiveTest` (#5407)

* test: ReverseStringRecursiveTest

* checkstyle: fix formatting

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../strings/ReverseStringRecursive.java       |  2 +-
 .../strings/ReverseStringRecursiveTest.java   | 31 +++++--------------
 2 files changed, 9 insertions(+), 24 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java b/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java
index e180f6c3991b..817b0a8ccd09 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java
@@ -3,10 +3,10 @@
 /**
  * Reverse String using Recursion
  */
-
 public final class ReverseStringRecursive {
     private ReverseStringRecursive() {
     }
+
     /**
      * @param str string to be reversed
      * @return reversed string
diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java
index b33037f37cfd..19daa61f48ca 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java
@@ -2,30 +2,15 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class ReverseStringRecursiveTest {
-    @Test
-    void shouldAcceptWhenEmptyStringIsPassed() {
-        String expected = "";
-        String reversed = ReverseStringRecursive.reverse("");
-
-        assertEquals(expected, reversed);
-    }
-
-    @Test
-    void shouldAcceptNotWhenWhenSingleCharacterIsPassed() {
-        String expected = "a";
-        String reversed = ReverseStringRecursive.reverse("a");
-
-        assertEquals(expected, reversed);
-    }
-
-    @Test
-    void shouldAcceptWhenStringIsPassed() {
-        String expected = "dlroWolleH";
-        String reversed = ReverseStringRecursive.reverse("HelloWorld");
-
-        assertEquals(expected, reversed);
+    @ParameterizedTest
+    @CsvSource({"'Hello World', 'dlroW olleH'", "'helloworld', 'dlrowolleh'", "'123456789', '987654321'", "'', ''", "'A', 'A'", "'!123 ABC xyz!', '!zyx CBA 321!'", "'Abc 123 Xyz', 'zyX 321 cbA'", "'12.34,56;78:90', '09:87;65,43.21'", "'abcdEFGHiJKL', 'LKJiHGFEdcba'",
+        "'MixOf123AndText!', '!txeTdnA321fOxiM'"})
+    public void
+    testReverseString(String input, String expectedOutput) {
+        assertEquals(expectedOutput, ReverseStringRecursive.reverse(input));
     }
 }

From af7c4250101c44b69a6c3f39b776b2b0487785c6 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 27 Aug 2024 11:31:47 +0200
Subject: [PATCH 0348/1338] refactor: `NextSmallerElement` (#5412)

* refactor: NextSmallerElement

* checkstyle: fix formatting

* checkstyle: fix formatting

* checkstyle: remove redundant new line

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../stacks/NextSmallerElement.java            | 79 ++++++++-----------
 .../stacks/NextSmallerElementTest.java        | 29 +++++++
 2 files changed, 62 insertions(+), 46 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java b/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java
index 6eae06ad7efc..254bb3b4b2d7 100644
--- a/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java
+++ b/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java
@@ -3,70 +3,57 @@
 import java.util.Arrays;
 import java.util.Stack;
 
-/*
-    Given an array "input" you need to print the first smaller element for each element to the left
-   side of an array. For a given element x of an array, the Next Smaller element of that element is
-   the first smaller element to the left side of it. If no such element is present print -1.
-
-    Example
-    input = { 2, 7, 3, 5, 4, 6, 8 };
-    At i = 0
-    No elements to left of it : -1
-    At i = 1
-    Next smaller element between (0 , 0) is 2
-    At i = 2
-    Next smaller element between (0 , 1) is 2
-    At i = 3
-    Next smaller element between (0 , 2) is 3
-    At i = 4
-    Next smaller element between (0 , 3) is 3
-    At i = 5
-    Next smaller element between (0 , 4) is 4
-    At i = 6
-    Next smaller element between (0 , 5) is 6
-
-    result : [-1, 2, 2, 3, 3, 4, 6]
-
-    1) Create a new empty stack st
-
-    2) Iterate over array "input" , where "i"  goes from 0 to input.length -1.
-        a) We are looking for value just smaller than `input[i]`. So keep popping from "stack"
-           till elements in "stack.peek() >= input[i]" or stack becomes empty.
-        b) If the stack is non-empty, then the top element is our previous element. Else the
-   previous element does not exist. c) push input[i] in stack. 3) If elements are left then their
-   answer is -1
+/**
+ * Utility class to find the next smaller element for each element in a given integer array.
+ *
+ * <p>The next smaller element for an element x is the first smaller element on the left side of x in the array.
+ * If no such element exists, the result will contain -1 for that position.</p>
+ *
+ * <p>Example:</p>
+ * <pre>
+ * Input:  {2, 7, 3, 5, 4, 6, 8}
+ * Output: [-1, 2, 2, 3, 3, 4, 6]
+ * </pre>
  */
-
 public final class NextSmallerElement {
     private NextSmallerElement() {
     }
 
+    /**
+     * Finds the next smaller element for each element in the given array.
+     *
+     * @param array the input array of integers
+     * @return an array where each element is replaced by the next smaller element on the left side in the input array,
+     * or -1 if there is no smaller element.
+     * @throws IllegalArgumentException if the input array is null
+     */
     public static int[] findNextSmallerElements(int[] array) {
-        // base case
         if (array == null) {
-            return array;
+            throw new IllegalArgumentException("Input array cannot be null");
         }
-        Stack<Integer> stack = new Stack<>();
+
         int[] result = new int[array.length];
+        Stack<Integer> stack = new Stack<>();
+
+        // Initialize all elements to -1 (in case there is no smaller element)
         Arrays.fill(result, -1);
 
+        // Traverse the array from left to right
         for (int i = 0; i < array.length; i++) {
-            while (!stack.empty() && stack.peek() >= array[i]) {
+            // Maintain the stack such that the top of the stack is the next smaller element
+            while (!stack.isEmpty() && stack.peek() >= array[i]) {
                 stack.pop();
             }
-            if (stack.empty()) {
-                result[i] = -1;
-            } else {
+
+            // If stack is not empty, then the top is the next smaller element
+            if (!stack.isEmpty()) {
                 result[i] = stack.peek();
             }
+
+            // Push the current element onto the stack
             stack.push(array[i]);
         }
-        return result;
-    }
 
-    public static void main(String[] args) {
-        int[] input = {2, 7, 3, 5, 4, 6, 8};
-        int[] result = findNextSmallerElements(input);
-        System.out.println(Arrays.toString(result));
+        return result;
     }
 }
diff --git a/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java b/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java
new file mode 100644
index 000000000000..62578baa6632
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class NextSmallerElementTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testFindNextSmallerElements(int[] input, int[] expected) {
+        assertArrayEquals(expected, NextSmallerElement.findNextSmallerElements(input));
+    }
+
+    static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new int[] {2, 7, 3, 5, 4, 6, 8}, new int[] {-1, 2, 2, 3, 3, 4, 6}), Arguments.of(new int[] {5}, new int[] {-1}), Arguments.of(new int[] {1, 2, 3, 4, 5}, new int[] {-1, 1, 2, 3, 4}), Arguments.of(new int[] {5, 4, 3, 2, 1}, new int[] {-1, -1, -1, -1, -1}),
+            Arguments.of(new int[] {4, 5, 2, 25}, new int[] {-1, 4, -1, 2}), Arguments.of(new int[] {}, new int[] {}));
+    }
+
+    @Test
+    void testFindNextSmallerElementsExceptions() {
+        assertThrows(IllegalArgumentException.class, () -> NextSmallerElement.findNextSmallerElements(null));
+    }
+}

From e3ad3761fd7c0d6d82242e65fc4e398a9992105b Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 27 Aug 2024 12:02:50 +0200
Subject: [PATCH 0349/1338] refactor: `StringCompression` (#5410)

refactor: StringCompression

Co-authored-by: alxkm <alx@alx.com>
---
 .../strings/StringCompression.java              | 17 +++++++----------
 .../strings/StringCompressionTest.java          |  3 ++-
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/StringCompression.java b/src/main/java/com/thealgorithms/strings/StringCompression.java
index ddbee4c4f91a..85bc0e4db641 100644
--- a/src/main/java/com/thealgorithms/strings/StringCompression.java
+++ b/src/main/java/com/thealgorithms/strings/StringCompression.java
@@ -1,7 +1,8 @@
 package com.thealgorithms.strings;
-/*  References : https://en.wikipedia.org/wiki/Run-length_encoding
- * String compression algorithm deals with encoding the string, that is, shortening the size of the
- * string
+
+/**
+ * References : https://en.wikipedia.org/wiki/Run-length_encoding
+ * String compression algorithm deals with encoding the string, that is, shortening the size of the string
  * @author Swarga-codes (https://github.com/Swarga-codes)
  */
 public final class StringCompression {
@@ -14,19 +15,16 @@ private StringCompression() {
      * @return the compressed character array as string
      */
     public static String compress(String input) {
-        // Keeping the count as 1 since every element present will have atleast a count
-        // of 1
+        // Keeping the count as 1 since every element present will have at least a count of 1
         int count = 1;
         String compressedString = "";
-        // Base condition to check whether the array is of size 1, if it is then we
-        // return the array
+        // Base condition to check whether the array is of size 1, if it is then we return the array
         if (input.length() == 1) {
             return "" + input.charAt(0);
         }
         // If the array has a length greater than 1 we move into this loop
         for (int i = 0; i < input.length() - 1; i++) {
-            // here we check for similarity of the adjacent elements and change the count
-            // accordingly
+            // here we check for similarity of the adjacent elements and change the count accordingly
             if (input.charAt(i) == input.charAt(i + 1)) {
                 count = count + 1;
             }
@@ -54,7 +52,6 @@ public static String compress(String input) {
     public static String appendCount(String res, int count, char ch) {
         if (count > 1) {
             res += ch + "" + count;
-            count = 1;
         } else {
             res += ch + "";
         }
diff --git a/src/test/java/com/thealgorithms/strings/StringCompressionTest.java b/src/test/java/com/thealgorithms/strings/StringCompressionTest.java
index bbd56c19dc23..fdec311f8f0a 100644
--- a/src/test/java/com/thealgorithms/strings/StringCompressionTest.java
+++ b/src/test/java/com/thealgorithms/strings/StringCompressionTest.java
@@ -1,4 +1,5 @@
 package com.thealgorithms.strings;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.params.ParameterizedTest;
@@ -6,7 +7,7 @@
 
 public class StringCompressionTest {
     @ParameterizedTest
-    @CsvSource({"a,a", "aabbb,a2b3", "abbbc,ab3c", "aabccd,a2bc2d"})
+    @CsvSource({"'a', 'a'", "'aabbb', 'a2b3'", "'abbbc', 'ab3c'", "'aabccd', 'a2bc2d'", "'aaaabbbcccc', 'a4b3c4'", "'abcd', 'abcd'", "'aabbccdd', 'a2b2c2d2'", "'aaabbaa', 'a3b2a2'", "'', ''", "'a', 'a'", "'aaaaa', 'a5'", "'aabb', 'a2b2'", "'aabbbaaa', 'a2b3a3'", "'qwerty', 'qwerty'"})
     void stringCompressionTest(String input, String expectedOutput) {
         String output = StringCompression.compress(input);
         assertEquals(expectedOutput, output);

From 49d1c84cb7740613fcee5d6846843c3a8e123e6e Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 27 Aug 2024 13:00:11 +0200
Subject: [PATCH 0350/1338] refactor: `ReverseString`, test improvements
 (#5406)

* refactor: ReverseString

* refactor: refactor testing into two methods

* checkstyle: fix formatting

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../thealgorithms/strings/ReverseString.java  |  5 ---
 .../strings/ReverseStringTest.java            | 37 +++++++++----------
 2 files changed, 17 insertions(+), 25 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/ReverseString.java b/src/main/java/com/thealgorithms/strings/ReverseString.java
index b47a77e9226c..46a0494fcbb4 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseString.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseString.java
@@ -7,11 +7,6 @@ public final class ReverseString {
     private ReverseString() {
     }
 
-    public static void main(String[] args) {
-        assert reverse("abc123").equals("321cba");
-        assert reverse2("abc123").equals("321cba");
-    }
-
     /**
      * easiest way to reverses the string str and returns it
      *
diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
index e73f7afce8eb..501f702976ec 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
@@ -2,30 +2,27 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class ReverseStringTest {
 
-    @Test
-    public void testReverseString() {
-        String input1 = "Hello World";
-        String input2 = "helloworld";
-        String input3 = "123456789";
-        String input4 = "";
-
-        String expectedOutput1 = "dlroW olleH";
-        String expectedOutput2 = "dlrowolleh";
-        String expectedOutput3 = "987654321";
-        String expectedOutput4 = "";
+    private static Stream<Arguments> testCases() {
+        return Stream.of(Arguments.of("Hello World", "dlroW olleH"), Arguments.of("helloworld", "dlrowolleh"), Arguments.of("123456789", "987654321"), Arguments.of("", ""), Arguments.of("A", "A"), Arguments.of("ab", "ba"),
+            Arguments.of("  leading and trailing spaces  ", "  secaps gniliart dna gnidael  "), Arguments.of("!@#$%^&*()", ")(*&^%$#@!"), Arguments.of("MixOf123AndText!", "!txeTdnA321fOxiM"));
+    }
 
-        assertEquals(ReverseString.reverse(input1), expectedOutput1);
-        assertEquals(ReverseString.reverse(input2), expectedOutput2);
-        assertEquals(ReverseString.reverse(input3), expectedOutput3);
-        assertEquals(ReverseString.reverse(input4), expectedOutput4);
+    @ParameterizedTest
+    @MethodSource("testCases")
+    public void testReverseString(String input, String expectedOutput) {
+        assertEquals(expectedOutput, ReverseString.reverse(input));
+    }
 
-        assertEquals(ReverseString.reverse2(input1), expectedOutput1);
-        assertEquals(ReverseString.reverse2(input2), expectedOutput2);
-        assertEquals(ReverseString.reverse2(input3), expectedOutput3);
-        assertEquals(ReverseString.reverse2(input4), expectedOutput4);
+    @ParameterizedTest
+    @MethodSource("testCases")
+    public void testReverseString2(String input, String expectedOutput) {
+        assertEquals(expectedOutput, ReverseString.reverse2(input));
     }
 }

From fc5a70edc94bda6aff4a9f6ff8f32271b62b6c3e Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 27 Aug 2024 13:12:49 +0200
Subject: [PATCH 0351/1338] refactor: `ReturnSubsequence` (#5408)

* refactor: ReturnSubsequence

* checkstyle: fix formatting

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../others/ReturnSubsequence.java             | 55 ++++++++-----------
 .../others/ReturnSubsequenceTest.java         | 23 ++++++++
 2 files changed, 46 insertions(+), 32 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java

diff --git a/src/main/java/com/thealgorithms/others/ReturnSubsequence.java b/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
index ef376c47a8f8..7ef660ce6579 100644
--- a/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
+++ b/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
@@ -1,46 +1,37 @@
 package com.thealgorithms.others;
 
-import java.util.Scanner;
-
+/**
+ * Class for generating all subsequences of a given string.
+ */
 public final class ReturnSubsequence {
     private ReturnSubsequence() {
     }
 
-    public static void main(String[] args) {
-        System.out.println("Enter String: ");
-        Scanner s = new Scanner(System.in);
-        String givenString = s.next(); // given string
-        String[] subsequence = returnSubsequence(givenString); // calling returnSubsequence() function
-        System.out.println("Subsequences : ");
-        // print the given array of subsequences
-        for (int i = 0; i < subsequence.length; i++) {
-            System.out.println(subsequence[i]);
-        }
-        s.close();
-    }
-
     /**
-     * @param givenString
-     * @return subsequence
+     * Generates all subsequences of the given string.
+     *
+     * @param input The input string.
+     * @return An array of subsequences.
      */
-    private static String[] returnSubsequence(String givenString) {
-        if (givenString.length() == 0) { // in it // If string is empty we will create an array of
-                                         // size=1 and insert "" (Empty string)
-            String[] ans = new String[1];
-            ans[0] = "";
-            return ans;
+    public static String[] getSubsequences(String input) {
+        if (input.isEmpty()) {
+            return new String[] {""}; // Return array with an empty string if input is empty
         }
-        String[] smallAns = returnSubsequence(givenString.substring(1)); // recursive call to get subsequences of substring starting from index
-        // position=1
 
-        String[] ans = new String[2 * smallAns.length]; // Our answer will be an array off string of size=2*smallAns
-        System.arraycopy(smallAns, 0, ans, 0, smallAns.length);
+        // Recursively find subsequences of the substring (excluding the first character)
+        String[] smallerSubsequences = getSubsequences(input.substring(1));
 
-        for (int k = 0; k < smallAns.length; k++) {
-            ans[k + smallAns.length] = givenString.charAt(0) + smallAns[k]; // Insert character at index=0 of the given
-                                                                            // substring in front of every string
-            // in smallAns
+        // Create an array to hold the final subsequences, double the size of smallerSubsequences
+        String[] result = new String[2 * smallerSubsequences.length];
+
+        // Copy the smaller subsequences directly to the result array
+        System.arraycopy(smallerSubsequences, 0, result, 0, smallerSubsequences.length);
+
+        // Prepend the first character of the input string to each of the smaller subsequences
+        for (int i = 0; i < smallerSubsequences.length; i++) {
+            result[i + smallerSubsequences.length] = input.charAt(0) + smallerSubsequences[i];
         }
-        return ans;
+
+        return result;
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java b/src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java
new file mode 100644
index 000000000000..0ae30c48c2a6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class ReturnSubsequenceTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testSubsequences(String input, String[] expected) {
+        String[] actual = ReturnSubsequence.getSubsequences(input);
+        assertArrayEquals(expected, actual);
+    }
+
+    static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of("", new String[] {""}), Arguments.of("a", new String[] {"", "a"}), Arguments.of("ab", new String[] {"", "b", "a", "ab"}), Arguments.of("abc", new String[] {"", "c", "b", "bc", "a", "ac", "ab", "abc"}),
+            Arguments.of("aab", new String[] {"", "b", "a", "ab", "a", "ab", "aa", "aab"}));
+    }
+}

From 633b9d4112698029dfff18160791a0372db996b1 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Tue, 27 Aug 2024 15:03:26 +0200
Subject: [PATCH 0352/1338] refactor: `PostfixToInfix` (#5409)

* refactor: PostfixToInfix

* checkstyle: fix formatting

* refactor: add support for one character

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../thealgorithms/stacks/PostfixToInfix.java  | 124 ++++++------------
 .../stacks/PostfixToInfixTest.java            |  33 +++++
 2 files changed, 74 insertions(+), 83 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
index 118a3df381c9..a8f98ac53e5d 100644
--- a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
+++ b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
@@ -20,81 +20,64 @@ public final class PostfixToInfix {
     private PostfixToInfix() {
     }
 
+    /**
+     * Determines if a given character is a valid arithmetic operator.
+     *
+     * @param token the character to check
+     * @return true if the character is an operator, false otherwise
+     */
     public static boolean isOperator(char token) {
-        switch (token) {
-        case '+':
-        case '-':
-        case '/':
-        case '*':
-        case '^':
-            return true;
-        default:
-            return false;
-        }
+        return token == '+' || token == '-' || token == '/' || token == '*' || token == '^';
     }
 
+    /**
+     * Validates whether a given string is a valid postfix expression.
+     *
+     * A valid postfix expression must meet these criteria:
+     * 1. It should have at least one operator and two operands.
+     * 2. The number of operands should always be greater than the number of operators at any point in the traversal.
+     *
+     * @param postfix the postfix expression string to validate
+     * @return true if the expression is valid, false otherwise
+     */
     public static boolean isValidPostfixExpression(String postfix) {
-        /* Postfix expression length should NOT be less than 3 */
-        if (postfix.length() < 3) {
-            return false;
+        if (postfix.length() == 1 && (Character.isAlphabetic(postfix.charAt(0)))) {
+            return true;
         }
 
-        /* First two characters should NOT be operators */
-        if (isOperator(postfix.charAt(0))) {
-            return false;
-        }
-        if (isOperator(postfix.charAt(1))) {
-            return false;
+        if (postfix.length() < 3) {
+            return false; // Postfix expression should have at least one operator and two operands
         }
 
         int operandCount = 0;
         int operatorCount = 0;
 
-        /* Traverse the postfix string to check if --> Number of operands = Number of operators + 1
-         */
-        for (int i = 0; i < postfix.length(); i++) {
-            char token = postfix.charAt(i);
-
+        for (char token : postfix.toCharArray()) {
             if (isOperator(token)) {
                 operatorCount++;
                 if (operatorCount >= operandCount) {
-                    return false;
+                    return false; // Invalid: more operators than operands at any point
                 }
             } else {
-                if (operatorCount == 0) {
-                    operandCount++;
-                    continue;
-                }
-
-                if (operandCount != operatorCount + 1) {
-                    return false;
-                }
-
-                /* Operand count is set to 2 because:-
-                 *
-                 * 1) the previous set of operands & operators combined have become a single valid
-                 * expression, which could be considered/assigned as a single operand.
-                 *
-                 * 2) the operand in the current iteration.
-                 */
-                operandCount = 2;
-
-                /* Reset operator count */
-                operatorCount = 0;
+                operandCount++;
             }
         }
 
-        return (operandCount == operatorCount + 1);
+        return operandCount == operatorCount + 1;
     }
 
+    /**
+     * Converts a valid postfix expression to an infix expression.
+     *
+     * @param postfix the postfix expression to convert
+     * @return the equivalent infix expression
+     * @throws IllegalArgumentException if the postfix expression is invalid
+     */
     public static String getPostfixToInfix(String postfix) {
-        String infix = "";
-
         if (postfix.isEmpty()) {
-            return infix;
+            return "";
         }
 
-        /* Validate Postfix expression before proceeding with the Infix conversion */
         if (!isValidPostfixExpression(postfix)) {
             throw new IllegalArgumentException("Invalid Postfix Expression");
         }
@@ -102,43 +85,18 @@ public static String getPostfixToInfix(String postfix) {
         Stack<String> stack = new Stack<>();
         StringBuilder valueString = new StringBuilder();
 
-        String operandA;
-        String operandB;
-        char operator;
-
-        for (int index = 0; index < postfix.length(); index++) {
-            char token = postfix.charAt(index);
-
+        for (char token : postfix.toCharArray()) {
             if (!isOperator(token)) {
                 stack.push(Character.toString(token));
-                continue;
+            } else {
+                String operandB = stack.pop();
+                String operandA = stack.pop();
+                valueString.append('(').append(operandA).append(token).append(operandB).append(')');
+                stack.push(valueString.toString());
+                valueString.setLength(0);
             }
-
-            operator = token;
-            operandB = stack.pop();
-            operandA = stack.pop();
-
-            valueString.append('(');
-
-            valueString.append(operandA);
-            valueString.append(operator);
-            valueString.append(operandB);
-
-            valueString.append(')');
-
-            stack.push(valueString.toString());
-            valueString.setLength(0);
         }
 
-        infix = stack.pop();
-        return infix;
-    }
-
-    public static void main(String[] args) {
-        assert getPostfixToInfix("ABC+/").equals("(A/(B+C))");
-        assert getPostfixToInfix("AB+CD+*").equals("((A+B)*(C+D))");
-        assert getPostfixToInfix("AB+C+D+").equals("(((A+B)+C)+D)");
-        assert getPostfixToInfix("ABCDE^*/-").equals("(A-(B/(C*(D^E))))");
-        assert getPostfixToInfix("AB+CD^/E*FGH+-^").equals("((((A+B)/(C^D))*E)^(F-(G+H)))");
+        return stack.pop();
     }
 }
diff --git a/src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java b/src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java
new file mode 100644
index 000000000000..a018865e69ec
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class PostfixToInfixTest {
+
+    @ParameterizedTest
+    @MethodSource("provideValidPostfixToInfixTestCases")
+    void testValidPostfixToInfixConversion(String postfix, String expectedInfix) {
+        assertEquals(expectedInfix, PostfixToInfix.getPostfixToInfix(postfix));
+    }
+
+    static Stream<Arguments> provideValidPostfixToInfixTestCases() {
+        return Stream.of(Arguments.of("A", "A"), Arguments.of("ABC+/", "(A/(B+C))"), Arguments.of("AB+CD+*", "((A+B)*(C+D))"), Arguments.of("AB+C+D+", "(((A+B)+C)+D)"), Arguments.of("ABCDE^*/-", "(A-(B/(C*(D^E))))"), Arguments.of("AB+CD^/E*FGH+-^", "((((A+B)/(C^D))*E)^(F-(G+H)))"));
+    }
+
+    @Test
+    void testEmptyPostfixExpression() {
+        assertEquals("", PostfixToInfix.getPostfixToInfix(""));
+    }
+
+    @Test
+    void testNullPostfixExpression() {
+        assertThrows(NullPointerException.class, () -> PostfixToInfix.getPostfixToInfix(null));
+    }
+}

From 298333bf455e6c5890157439d4696126e6fe139c Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 27 Aug 2024 23:36:15 +0200
Subject: [PATCH 0353/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-surefire-plugin from 3.4.0 to 3.5.0 (#5417)

Chore(deps): bump org.apache.maven.plugins:maven-surefire-plugin

Bumps [org.apache.maven.plugins:maven-surefire-plugin](https://github.com/apache/maven-surefire) from 3.4.0 to 3.5.0.
- [Release notes](https://github.com/apache/maven-surefire/releases)
- [Commits](https://github.com/apache/maven-surefire/compare/surefire-3.4.0...surefire-3.5.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-surefire-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 18288b8cf805..c973dc5113be 100644
--- a/pom.xml
+++ b/pom.xml
@@ -63,7 +63,7 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.4.0</version>
+                <version>3.5.0</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>

From a9bc7c269d3146aa2d67d69f2922f1bb2b07b4c5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 27 Aug 2024 23:39:36 +0200
Subject: [PATCH 0354/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-pmd-plugin from 3.24.0 to 3.25.0 (#5418)

Chore(deps): bump org.apache.maven.plugins:maven-pmd-plugin

Bumps [org.apache.maven.plugins:maven-pmd-plugin](https://github.com/apache/maven-pmd-plugin) from 3.24.0 to 3.25.0.
- [Release notes](https://github.com/apache/maven-pmd-plugin/releases)
- [Commits](https://github.com/apache/maven-pmd-plugin/compare/maven-pmd-plugin-3.24.0...maven-pmd-plugin-3.25.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-pmd-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index c973dc5113be..0d2d32e6dd1d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -146,7 +146,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-pmd-plugin</artifactId>
-                <version>3.24.0</version>
+                <version>3.25.0</version>
                 <configuration>
                     <printFailingErrors>true</printFailingErrors>
                     <includeTests>true</includeTests>

From 45563ccbde3f4d9aadae178dffa17ebf333117ff Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 28 Aug 2024 18:31:39 +0200
Subject: [PATCH 0355/1338] test: `CircleLinkedListTest` (#5422)

* test: CircleLinkedListTest

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../lists/CircleLinkedList.java               | 37 ++++-----
 .../lists/CircleLinkedListTest.java           | 78 +++++++++++++++++++
 2 files changed, 91 insertions(+), 24 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
index 6eb9d75fe58f..2b50f73101fb 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
@@ -51,22 +51,25 @@ public void append(E value) {
         size++;
     }
 
-    // utility function for traversing the list
     public String toString() {
-        Node<E> p = head.next;
-        String s = "[ ";
-        while (p != head) {
-            s += p.value;
-            if (p != tail) {
-                s += " , ";
+        if (size == 0) {
+            return "[]";
+        }
+        StringBuilder sb = new StringBuilder("[ ");
+        Node<E> current = head.next;
+        while (current != head) {
+            sb.append(current.value);
+            if (current.next != head) {
+                sb.append(", ");
             }
-            p = p.next;
+            current = current.next;
         }
-        return s + " ]";
+        sb.append(" ]");
+        return sb.toString();
     }
 
     public E remove(int pos) {
-        if (pos > size || pos < 0) {
+        if (pos >= size || pos < 0) {
             // catching errors
             throw new IndexOutOfBoundsException("position cannot be greater than size or negative");
         }
@@ -89,18 +92,4 @@ public E remove(int pos) {
         size--;
         return saved;
     }
-
-    public static void main(String[] args) {
-        CircleLinkedList<Integer> cl = new CircleLinkedList<>();
-        cl.append(12);
-        System.out.println(cl);
-        cl.append(23);
-        System.out.println(cl);
-        cl.append(34);
-        System.out.println(cl);
-        cl.append(56);
-        System.out.println(cl);
-        cl.remove(3);
-        System.out.println(cl);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java
new file mode 100644
index 000000000000..b7a05ef29d66
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java
@@ -0,0 +1,78 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class CircleLinkedListTest {
+
+    @Test
+    public void testAppendAndSize() {
+        CircleLinkedList<Integer> list = new CircleLinkedList<>();
+        list.append(1);
+        list.append(2);
+        list.append(3);
+
+        assertEquals(3, list.getSize());
+        assertEquals("[ 1, 2, 3 ]", list.toString());
+    }
+
+    @Test
+    public void testRemove() {
+        CircleLinkedList<Integer> list = new CircleLinkedList<>();
+        list.append(1);
+        list.append(2);
+        list.append(3);
+        list.append(4);
+
+        assertEquals(2, list.remove(1));
+        assertEquals(3, list.remove(1));
+        assertEquals("[ 1, 4 ]", list.toString());
+        assertEquals(2, list.getSize());
+    }
+
+    @Test
+    public void testRemoveInvalidIndex() {
+        CircleLinkedList<Integer> list = new CircleLinkedList<>();
+        list.append(1);
+        list.append(2);
+
+        assertThrows(IndexOutOfBoundsException.class, () -> list.remove(2));
+        assertThrows(IndexOutOfBoundsException.class, () -> list.remove(-1));
+    }
+
+    @Test
+    public void testToStringEmpty() {
+        CircleLinkedList<Integer> list = new CircleLinkedList<>();
+        assertEquals("[]", list.toString());
+    }
+
+    @Test
+    public void testToStringAfterRemoval() {
+        CircleLinkedList<Integer> list = new CircleLinkedList<>();
+        list.append(1);
+        list.append(2);
+        list.append(3);
+        list.remove(1);
+
+        assertEquals("[ 1, 3 ]", list.toString());
+    }
+
+    @Test
+    public void testSingleElement() {
+        CircleLinkedList<Integer> list = new CircleLinkedList<>();
+        list.append(1);
+
+        assertEquals(1, list.getSize());
+        assertEquals("[ 1 ]", list.toString());
+        assertEquals(1, list.remove(0));
+        assertEquals("[]", list.toString());
+    }
+
+    @Test
+    public void testNullElement() {
+        CircleLinkedList<String> list = new CircleLinkedList<>();
+        assertThrows(NullPointerException.class, () -> list.append(null));
+    }
+}

From c413f3c6b2d031c1eb0e015d606d4cfd09e2be8f Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 28 Aug 2024 18:35:21 +0200
Subject: [PATCH 0356/1338] refactor: `LongestPalindromicSubstring` (#5420)

* refactor: LongestPalindromicSubstring

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../LongestPalindromicSubstring.java          | 23 +++++++------------
 .../LongestPalindromicSubstringTest.java      | 22 ++++++++++++++++++
 2 files changed, 30 insertions(+), 15 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
index c6ae55919b82..8a4ab2f526a9 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java
@@ -1,25 +1,18 @@
 package com.thealgorithms.dynamicprogramming;
 
-/*
- * Algorithm explanation https://leetcode.com/problems/longest-palindromic-substring/
+/**
+ * Class for finding the longest palindromic substring within a given string.
+ * <p>
+ * A palindromic substring is a sequence of characters that reads the same backward as forward.
+ * This class uses a dynamic programming approach to efficiently find the longest palindromic substring.
+ *
  */
 public final class LongestPalindromicSubstring {
     private LongestPalindromicSubstring() {
     }
 
-    public static void main(String[] args) {
-        String a = "babad";
-        String b = "cbbd";
-
-        String aLPS = lps(a);
-        String bLPS = lps(b);
-
-        System.out.println(a + " => " + aLPS);
-        System.out.println(b + " => " + bLPS);
-    }
-
-    private static String lps(String input) {
-        if (input == null || input.length() == 0) {
+    public static String lps(String input) {
+        if (input == null || input.isEmpty()) {
             return input;
         }
         boolean[][] arr = new boolean[input.length()][input.length()];
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java
new file mode 100644
index 000000000000..278de7e10e0a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class LongestPalindromicSubstringTest {
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            Arguments.of("babad", "aba"), Arguments.of("cbbd", "bb"), Arguments.of("a", "a"), Arguments.of("x", "x"), Arguments.of("", ""), Arguments.of("aaaa", "aaaa"), Arguments.of("mm", "mm"), Arguments.of("level", "level"), Arguments.of("bananas", "anana"), Arguments.of("abacabad", "abacaba"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testLps(String input, String expected) {
+        assertEquals(expected, LongestPalindromicSubstring.lps(input));
+    }
+}

From b2815db5cd6d19d0a94424fbb27ea53201085a12 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 28 Aug 2024 18:40:27 +0200
Subject: [PATCH 0357/1338] refactor: `LongestNonRepetitiveSubstring` (#5421)

* refactor: LongestNonRepetitiveSubstring

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../LongestNonRepetitiveSubstring.java        | 59 ++++++++-----------
 .../LongestNonRepetitiveSubstringTest.java    | 23 +++++---
 2 files changed, 41 insertions(+), 41 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java b/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java
index c113162ff435..6808cd50602f 100644
--- a/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java
+++ b/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java
@@ -3,47 +3,40 @@
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * Class for finding the length of the longest substring without repeating characters.
+ */
 final class LongestNonRepetitiveSubstring {
     private LongestNonRepetitiveSubstring() {
     }
 
+    /**
+     * Finds the length of the longest substring without repeating characters.
+     *
+     * @param s the input string
+     * @return the length of the longest non-repetitive substring
+     */
     public static int lengthOfLongestSubstring(String s) {
-        int max = 0;
+        int maxLength = 0;
         int start = 0;
-        int i = 0;
-        Map<Character, Integer> map = new HashMap<>();
-
-        while (i < s.length()) {
-            char temp = s.charAt(i);
-
-            // adding key to map if not present
-            if (!map.containsKey(temp)) {
-                map.put(temp, 0);
-            } else if (s.charAt(start) == temp) {
-                start++;
-            } else if (s.charAt(i - 1) == temp) {
-                if (max < map.size()) {
-                    max = map.size();
-                }
-                map = new HashMap<>();
-                start = i;
-                i--;
-            } else {
-                if (max < map.size()) {
-                    max = map.size();
-                }
-                while (s.charAt(start) != temp) {
-                    map.remove(s.charAt(start));
-                    start++;
-                }
-                start++;
+        Map<Character, Integer> charIndexMap = new HashMap<>();
+
+        for (int i = 0; i < s.length(); i++) {
+            char currentChar = s.charAt(i);
+
+            // If the character is already in the map and its index is within the current window
+            if (charIndexMap.containsKey(currentChar) && charIndexMap.get(currentChar) >= start) {
+                // Move the start to the position right after the last occurrence of the current character
+                start = charIndexMap.get(currentChar) + 1;
             }
 
-            i++;
-        }
-        if (max < map.size()) {
-            max = map.size();
+            // Update the last seen index of the current character
+            charIndexMap.put(currentChar, i);
+
+            // Calculate the maximum length of the substring without repeating characters
+            maxLength = Math.max(maxLength, i - start + 1);
         }
-        return max;
+
+        return maxLength;
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java b/src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java
index c6fd8c59c53e..791c4ba3ae32 100644
--- a/src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java
+++ b/src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java
@@ -1,15 +1,22 @@
 package com.thealgorithms.strings;
 
-import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class LongestNonRepetitiveSubstringTest {
 
-    @Test
-    public void palindrome() {
-        String input1 = "HelloWorld";
-        String input2 = "javaIsAProgrammingLanguage";
-        Assertions.assertEquals(LongestNonRepetitiveSubstring.lengthOfLongestSubstring(input1), 5);
-        Assertions.assertEquals(LongestNonRepetitiveSubstring.lengthOfLongestSubstring(input2), 9);
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of("", 0), Arguments.of("a", 1), Arguments.of("abcde", 5), Arguments.of("aaaaa", 1), Arguments.of("abca", 3), Arguments.of("abcdeabc", 5), Arguments.of("a1b2c3", 6), Arguments.of("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890", 62),
+            Arguments.of("aabb", 2), Arguments.of("abcdefghijabc", 10));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testLengthOfLongestSubstring(String input, int expectedLength) {
+        assertEquals(expectedLength, LongestNonRepetitiveSubstring.lengthOfLongestSubstring(input));
     }
 }

From 0733075498ee41f4d750d64e2168c635c528ee5b Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 28 Aug 2024 18:45:23 +0200
Subject: [PATCH 0358/1338] test: `CountCharTest` (#5423)

test: CountCharTest

Co-authored-by: alxkm <alx@alx.com>
---
 .../com/thealgorithms/others/CountChar.java    | 11 +++++++----
 .../thealgorithms/others/CountCharTest.java    | 18 +++++++++++++-----
 2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/CountChar.java b/src/main/java/com/thealgorithms/others/CountChar.java
index ad858137726b..00cff6860216 100644
--- a/src/main/java/com/thealgorithms/others/CountChar.java
+++ b/src/main/java/com/thealgorithms/others/CountChar.java
@@ -5,13 +5,16 @@ private CountChar() {
     }
 
     /**
-     * Count non space character in string
+     * Counts the number of non-whitespace characters in the given string.
      *
-     * @param str String to count the characters
-     * @return number of character in the specified string
+     * @param str the input string to count the characters in
+     * @return the number of non-whitespace characters in the specified string;
+     *         returns 0 if the input string is null
      */
-
     public static int countCharacters(String str) {
+        if (str == null) {
+            return 0;
+        }
         return str.replaceAll("\\s", "").length();
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/CountCharTest.java b/src/test/java/com/thealgorithms/others/CountCharTest.java
index 382ba4246400..2b87d3806002 100644
--- a/src/test/java/com/thealgorithms/others/CountCharTest.java
+++ b/src/test/java/com/thealgorithms/others/CountCharTest.java
@@ -2,15 +2,23 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 class CountCharTest {
 
-    @Test
-    void testCountCharacters() {
-        String input = "12345";
-        int expectedValue = 5;
+    @ParameterizedTest(name = "\"{0}\" should have {1} non-whitespace characters")
+    @CsvSource({"'', 0", "'   ', 0", "'a', 1", "'abc', 3", "'a b c', 3", "'   a   b   c   ', 3", "'\tabc\n', 3", "'  a   b\tc  ', 3", "' 12345 ', 5", "'Hello, World!', 12"})
+    @DisplayName("Test countCharacters with various inputs")
+    void testCountCharacters(String input, int expected) {
+        assertEquals(expected, CountChar.countCharacters(input));
+    }
 
-        assertEquals(expectedValue, CountChar.countCharacters(input));
+    @Test
+    @DisplayName("Test countCharacters with null input")
+    void testCountCharactersNullInput() {
+        assertEquals(0, CountChar.countCharacters(null));
     }
 }

From 7d1847f51ca1911f177b49b572455f100c69a95f Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 28 Aug 2024 20:53:00 +0200
Subject: [PATCH 0359/1338] refactor: `PalindromicPartitioning` (#5419)

refactor: PalindromicPartitioning

Co-authored-by: alxkm <alx@alx.com>
---
 .../PalindromicPartitioning.java              | 45 ++++++++-----------
 .../PalindromicPartitioningTest.java          | 21 +++++++++
 2 files changed, 40 insertions(+), 26 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioningTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java b/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
index 01fa1d19609a..a323a9a06f7d 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java
@@ -1,27 +1,31 @@
 package com.thealgorithms.dynamicprogramming;
 
-import java.util.Scanner;
-
 /**
- * @file @brief Implements [Palindrome
- * Partitioning](https://leetcode.com/problems/palindrome-partitioning-ii/)
- * algorithm, giving you the minimum number of partitions you need to make
+ * Provides functionality to solve the Palindrome Partitioning II problem, which involves finding
+ * the minimum number of partitions needed to divide a given string into palindromic substrings.
+ *
+ * <p>
+ * The problem is solved using dynamic programming. The approach involves checking all possible
+ * substrings and determining whether they are palindromes. The minimum number of cuts required
+ * for palindrome partitioning is computed in a bottom-up manner.
+ * </p>
+ *
+ * <p>
+ * Example:
+ * <ul>
+ *     <li>Input: "nitik" => Output: 2 (Partitioning: "n | iti | k")</li>
+ *     <li>Input: "ababbbabbababa" => Output: 3 (Partitioning: "aba | b | bbabb | ababa")</li>
+ * </ul>
+ * </p>
  *
- * @details palindrome partitioning uses dynamic programming and goes to all the
- * possible partitions to find the minimum you are given a string and you need
- * to give minimum number of partitions needed to divide it into a number of
- * palindromes [Palindrome Partitioning]
- * (https://www.geeksforgeeks.org/palindrome-partitioning-dp-17/) overall time
- * complexity O(n^2) For example: example 1:- String : "nitik" Output : 2 => "n
- * | iti | k" For example: example 2:- String : "ababbbabbababa" Output : 3 =>
- * "aba | b | bbabb | ababa"
- * @author [Syed] (https://github.com/roeticvampire)
+ * @see <a href="https://leetcode.com/problems/palindrome-partitioning-ii/">Palindrome Partitioning II</a>
+ * @see <a href="https://www.geeksforgeeks.org/palindrome-partitioning-dp-17/">Palindrome Partitioning (GeeksforGeeks)</a>
  */
 public final class PalindromicPartitioning {
     private PalindromicPartitioning() {
     }
 
-    public static int minimalpartitions(String word) {
+    public static int minimalPartitions(String word) {
         int len = word.length();
         /* We Make two arrays to create a bottom-up solution.
            minCuts[i] = Minimum number of cuts needed for palindrome partitioning of substring
@@ -76,15 +80,4 @@ public static int minimalpartitions(String word) {
         // string. i.e., str[0..n-1]
         return minCuts[len - 1];
     }
-
-    public static void main(String[] args) {
-        Scanner input = new Scanner(System.in);
-        String word;
-        System.out.println("Enter the First String");
-        word = input.nextLine();
-        // ans stores the final minimal cut count needed for partitioning
-        int ans = minimalpartitions(word);
-        System.out.println("The minimum cuts needed to partition \"" + word + "\" into palindromes is " + ans);
-        input.close();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioningTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioningTest.java
new file mode 100644
index 000000000000..be503359e770
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioningTest.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class PalindromicPartitioningTest {
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of("a", 0), Arguments.of("aa", 0), Arguments.of("ab", 1), Arguments.of("ababbbabbababa", 3), Arguments.of("abcde", 4), Arguments.of("abacdcaba", 0));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testMinimalPartitions(String input, int expected) {
+        assertEquals(expected, PalindromicPartitioning.minimalPartitions(input));
+    }
+}

From 203d54466897201b9d832afec5f4120f6d6dcbcd Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 28 Aug 2024 20:56:58 +0200
Subject: [PATCH 0360/1338] test: `LongestValidParenthesesTest` (#5416)

* test: LongestValidParenthesesTest

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../LongestValidParenthesesTest               | 51 -------------------
 .../LongestValidParenthesesTest.java          | 22 ++++++++
 2 files changed, 22 insertions(+), 51 deletions(-)
 delete mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java

diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest b/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest
deleted file mode 100644
index b2b28ffd3019..000000000000
--- a/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest
+++ /dev/null
@@ -1,51 +0,0 @@
-package com.thealgorithms.dynamicprogramming;
-
-import org.junit.jupiter.api.Test;
-import static org.junit.jupiter.api.Assertions.*;
-
-class LongestValidParenthesesTest {
-
-    LongestValidParentheses longestValidParentheses = new LongestValidParentheses();
-
-    @Test
-    void shouldReturnZeroWhenSingleOpeningParenthesisIsGiven() {
-        String input = "(";
-        int validLength = longestValidParentheses.getLongestValidParentheses(input);
-        assertEquals(0, validLength);
-    }
-
-    @Test
-    void shouldReturnZeroWhenSingleClosingParenthesisIsGiven() {
-        String input = ")";
-        int validLength = longestValidParentheses.getLongestValidParentheses(input);
-        assertEquals(0, validLength);
-    }
-
-    @Test
-    void shouldReturnZeroWhenNullStringIsGiven() {
-        String input = "";
-        int validLength = longestValidParentheses.getLongestValidParentheses(input);
-        assertEquals(0, validLength);
-    }
-
-    @Test
-    void shouldReturnTwoWhenTwoBalancedParenthesesAreGiven() {
-        String input = "()";
-        int validLength = longestValidParentheses.getLongestValidParentheses(input);
-        assertEquals(2, validLength);
-    }
-
-    @Test
-    void shouldReturnLengthWhenInputStringIsValid() {
-        String input = "()((()))";
-        int validLength = longestValidParentheses.getLongestValidParentheses(input);
-        assertEquals(8, validLength);
-    }
-
-    @Test
-    void shouldReturnValidLengthWhenInputStringIsGiven() {
-        String input = "((()((())))";
-        int validLength = longestValidParentheses.getLongestValidParentheses(input);
-        assertEquals(10, validLength);
-    }
-}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java
new file mode 100644
index 000000000000..77b7dda6a972
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class LongestValidParenthesesTest {
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of("", 0), Arguments.of("(", 0), Arguments.of(")", 0), Arguments.of("()", 2), Arguments.of("(())", 4), Arguments.of("()()", 4), Arguments.of(")(", 0), Arguments.of("(()", 2), Arguments.of("())(", 2), Arguments.of("(()())", 6), Arguments.of("(((())))", 8),
+            Arguments.of("(()))(()", 4), Arguments.of("()()()(", 6), Arguments.of("(()())()(", 8), Arguments.of("((((((", 0), Arguments.of("))))))", 0), Arguments.of("(()())(", 6), Arguments.of("))()(", 2), Arguments.of("()((()))", 8), Arguments.of("((()((())))", 10));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testLongestValidParentheses(String input, int expected) {
+        assertEquals(expected, LongestValidParentheses.getLongestValidParentheses(input));
+    }
+}

From 6b7a1fdbe87ad472b6acd710639b0390440a865e Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 28 Aug 2024 22:25:46 +0200
Subject: [PATCH 0361/1338] refactor: `QueueUsingTwoStacks` (#5427)

refactor: QueueUsingTwoStacks

Co-authored-by: alxkm <alx@alx.com>
---
 .../others/QueueUsingTwoStacks.java           |  82 +---------
 .../others/QueueUsingTwoStacksTest.java       | 145 ++++++++++++++++++
 2 files changed, 151 insertions(+), 76 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java

diff --git a/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java b/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java
index 259e108a354d..b43110d4d3ff 100644
--- a/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java
+++ b/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java
@@ -15,17 +15,14 @@
  *
  * @author sahilb2 (https://www.github.com/sahilb2)
  */
-class QueueWithStack {
-
-    // Stack to keep track of elements inserted into the queue
-    private Stack<Object> inStack;
-    // Stack to keep track of elements to be removed next in queue
-    private Stack<Object> outStack;
+public class QueueUsingTwoStacks {
+    private final Stack<Object> inStack;
+    private final Stack<Object> outStack;
 
     /**
      * Constructor
      */
-    QueueWithStack() {
+    public QueueUsingTwoStacks() {
         this.inStack = new Stack<>();
         this.outStack = new Stack<>();
     }
@@ -94,7 +91,7 @@ public boolean isEmpty() {
      * @return true if the inStack is empty.
      */
     public boolean isInStackEmpty() {
-        return (inStack.size() == 0);
+        return (inStack.isEmpty());
     }
 
     /**
@@ -103,73 +100,6 @@ public boolean isInStackEmpty() {
      * @return true if the outStack is empty.
      */
     public boolean isOutStackEmpty() {
-        return (outStack.size() == 0);
-    }
-}
-
-/**
- * This class is the example for the Queue class
- *
- * @author sahilb2 (https://www.github.com/sahilb2)
- */
-public final class QueueUsingTwoStacks {
-    private QueueUsingTwoStacks() {
-    }
-
-    /**
-     * Main method
-     *
-     * @param args Command line arguments
-     */
-    public static void main(String[] args) {
-        QueueWithStack myQueue = new QueueWithStack();
-        myQueue.insert(1);
-        System.out.println(myQueue.peekBack()); // Will print 1
-        // instack: [(top) 1]
-        // outStack: []
-        myQueue.insert(2);
-        System.out.println(myQueue.peekBack()); // Will print 2
-        // instack: [(top) 2, 1]
-        // outStack: []
-        myQueue.insert(3);
-        System.out.println(myQueue.peekBack()); // Will print 3
-        // instack: [(top) 3, 2, 1]
-        // outStack: []
-        myQueue.insert(4);
-        System.out.println(myQueue.peekBack()); // Will print 4
-        // instack: [(top) 4, 3, 2, 1]
-        // outStack: []
-
-        System.out.println(myQueue.isEmpty()); // Will print false
-
-        System.out.println(myQueue.remove()); // Will print 1
-        System.out.println((myQueue.isInStackEmpty()) ? "null" : myQueue.peekBack()); // Will print NULL
-        // instack: []
-        // outStack: [(top) 2, 3, 4]
-
-        myQueue.insert(5);
-        System.out.println(myQueue.peekFront()); // Will print 2
-        // instack: [(top) 5]
-        // outStack: [(top) 2, 3, 4]
-
-        myQueue.remove();
-        System.out.println(myQueue.peekFront()); // Will print 3
-        // instack: [(top) 5]
-        // outStack: [(top) 3, 4]
-        myQueue.remove();
-        System.out.println(myQueue.peekFront()); // Will print 4
-        // instack: [(top) 5]
-        // outStack: [(top) 4]
-        myQueue.remove();
-        // instack: [(top) 5]
-        // outStack: []
-        System.out.println(myQueue.peekFront()); // Will print 5
-        // instack: []
-        // outStack: [(top) 5]
-        myQueue.remove();
-        // instack: []
-        // outStack: []
-
-        System.out.println(myQueue.isEmpty()); // Will print true
+        return (outStack.isEmpty());
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java b/src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java
new file mode 100644
index 000000000000..4901b9c0d3a1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java
@@ -0,0 +1,145 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.EmptyStackException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class QueueUsingTwoStacksTest {
+
+    private QueueUsingTwoStacks queue;
+
+    @BeforeEach
+    void setUp() {
+        queue = new QueueUsingTwoStacks();
+    }
+
+    @Test
+    void testIsEmptyInitially() {
+        assertTrue(queue.isEmpty(), "Queue should be empty initially");
+    }
+
+    @Test
+    void testInsertSingleElement() {
+        queue.insert(1);
+        assertFalse(queue.isEmpty(), "Queue should not be empty after inserting an element");
+        assertEquals(1, queue.peekFront(), "The front element should be the inserted element");
+    }
+
+    @Test
+    void testRemoveSingleElement() {
+        queue.insert(1);
+        assertEquals(1, queue.remove(), "Removing should return the first inserted element");
+        assertTrue(queue.isEmpty(), "Queue should be empty after removing the only element");
+    }
+
+    @Test
+    void testRemoveMultipleElements() {
+        queue.insert(1);
+        queue.insert(2);
+        queue.insert(3);
+        assertEquals(1, queue.remove(), "First removed element should be the first inserted element");
+        assertEquals(2, queue.remove(), "Second removed element should be the second inserted element");
+        assertEquals(3, queue.remove(), "Third removed element should be the third inserted element");
+        assertTrue(queue.isEmpty(), "Queue should be empty after removing all elements");
+    }
+
+    @Test
+    void testPeekFrontWithMultipleElements() {
+        queue.insert(1);
+        queue.insert(2);
+        queue.insert(3);
+        assertEquals(1, queue.peekFront(), "The front element should be the first inserted element");
+    }
+
+    @Test
+    void testPeekBackWithMultipleElements() {
+        queue.insert(1);
+        queue.insert(2);
+        queue.insert(3);
+        assertEquals(3, queue.peekBack(), "The back element should be the last inserted element");
+    }
+
+    @Test
+    void testPeekFrontAfterRemovals() {
+        queue.insert(1);
+        queue.insert(2);
+        queue.insert(3);
+        queue.remove();
+        assertEquals(2, queue.peekFront(), "After removing one element, the front should be the second element");
+    }
+
+    @Test
+    void testIsEmptyAfterRemovals() {
+        queue.insert(1);
+        queue.insert(2);
+        queue.remove();
+        queue.remove();
+        assertTrue(queue.isEmpty(), "Queue should be empty after removing all elements");
+    }
+
+    @Test
+    void testRemoveFromEmptyQueue() {
+        org.junit.jupiter.api.Assertions.assertThrows(EmptyStackException.class, queue::remove, "Removing from an empty queue should throw an exception");
+    }
+
+    @Test
+    void testPeekFrontFromEmptyQueue() {
+        org.junit.jupiter.api.Assertions.assertThrows(EmptyStackException.class, queue::peekFront, "Peeking front from an empty queue should throw an exception");
+    }
+
+    @Test
+    void testPeekBackFromEmptyQueue() {
+        org.junit.jupiter.api.Assertions.assertThrows(EmptyStackException.class, queue::peekBack, "Peeking back from an empty queue should throw an exception");
+    }
+
+    @Test
+    void testIsInStackEmptyInitially() {
+        assertTrue(queue.isInStackEmpty(), "inStack should be empty initially");
+    }
+
+    @Test
+    void testIsOutStackEmptyInitially() {
+        assertTrue(queue.isOutStackEmpty(), "outStack should be empty initially");
+    }
+
+    @Test
+    void testIsInStackEmptyAfterInsertion() {
+        queue.insert(1);
+        assertFalse(queue.isInStackEmpty(), "inStack should not be empty after an insertion");
+    }
+
+    @Test
+    void testIsOutStackEmptyAfterInsertion() {
+        queue.insert(1);
+        assertTrue(queue.isOutStackEmpty(), "outStack should still be empty after an insertion");
+    }
+
+    @Test
+    void testIsOutStackEmptyAfterRemoval() {
+        queue.insert(1);
+        queue.remove();
+        assertTrue(queue.isOutStackEmpty(), "outStack should be empty after removing the only element");
+    }
+
+    @Test
+    void testIsInStackEmptyAfterMultipleRemovals() {
+        queue.insert(1);
+        queue.insert(2);
+        queue.remove();
+        queue.remove();
+        assertTrue(queue.isInStackEmpty(), "inStack should be empty after removing all elements");
+    }
+
+    @Test
+    void testIsOutStackEmptyAfterMultipleRemovals() {
+        queue.insert(1);
+        queue.insert(2);
+        queue.remove();
+        queue.remove();
+        assertTrue(queue.isOutStackEmpty(), "outStack should be empty after removing all elements");
+    }
+}

From a23e9b0ba892270fe769c4cc878635eeccc14f0e Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 28 Aug 2024 22:29:24 +0200
Subject: [PATCH 0362/1338] refactor: `HashMap` (#5426)

* refactor: HashMap

* checkstyle: fix formatting

* refactor: remove redundant comments

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../hashmap/hashing/HashMap.java              | 307 +++++++++++++-----
 .../datastructures/hashmap/hashing/Main.java  |  52 ---
 .../hashmap/hashing/HashMapTest.java          | 146 +++++++++
 3 files changed, 364 insertions(+), 141 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
index e0b394b12bf6..1aae122b48ec 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
@@ -1,146 +1,275 @@
 package com.thealgorithms.datastructures.hashmap.hashing;
 
-public class HashMap {
+/**
+ * A generic HashMap implementation that uses separate chaining with linked lists
+ * to handle collisions. The class supports basic operations such as insert, delete,
+ * and search, as well as displaying the contents of the hash map.
+ *
+ * @param <K> the type of keys maintained by this map
+ * @param <V> the type of mapped values
+ */
+public class HashMap<K, V> {
+    private final int hashSize;
+    private final LinkedList<K, V>[] buckets;
 
-    private final int hsize;
-    private final LinkedList[] buckets;
-
-    public HashMap(int hsize) {
-        buckets = new LinkedList[hsize];
-        for (int i = 0; i < hsize; i++) {
-            buckets[i] = new LinkedList();
-            // Java requires explicit initialization of each object
+    /**
+     * Constructs a HashMap with the specified hash size.
+     *
+     * @param hashSize the number of buckets in the hash map
+     */
+    @SuppressWarnings("unchecked")
+    public HashMap(int hashSize) {
+        this.hashSize = hashSize;
+        // Safe to suppress warning because we are creating an array of generic type
+        this.buckets = new LinkedList[hashSize];
+        for (int i = 0; i < hashSize; i++) {
+            buckets[i] = new LinkedList<>();
         }
-        this.hsize = hsize;
     }
 
-    public int hashing(int key) {
-        int hash = key % hsize;
-        if (hash < 0) {
-            hash += hsize;
+    /**
+     * Computes the hash code for the specified key.
+     * Null keys are hashed to bucket 0.
+     *
+     * @param key the key for which the hash code is to be computed
+     * @return the hash code corresponding to the key
+     */
+    private int computeHash(K key) {
+        if (key == null) {
+            return 0; // Use a special bucket (e.g., bucket 0) for null keys
         }
-        return hash;
+        int hash = key.hashCode() % hashSize;
+        return hash < 0 ? hash + hashSize : hash;
     }
 
-    public void insertHash(int key) {
-        int hash = hashing(key);
-        buckets[hash].insert(key);
+    /**
+     * Inserts the specified key-value pair into the hash map.
+     * If the key already exists, the value is updated.
+     *
+     * @param key   the key to be inserted
+     * @param value the value to be associated with the key
+     */
+    public void insert(K key, V value) {
+        int hash = computeHash(key);
+        buckets[hash].insert(key, value);
     }
 
-    public void deleteHash(int key) {
-        int hash = hashing(key);
-
+    /**
+     * Deletes the key-value pair associated with the specified key from the hash map.
+     *
+     * @param key the key whose key-value pair is to be deleted
+     */
+    public void delete(K key) {
+        int hash = computeHash(key);
         buckets[hash].delete(key);
     }
 
-    public void displayHashtable() {
-        for (int i = 0; i < hsize; i++) {
-            System.out.printf("Bucket %d :", i);
-            System.out.println(buckets[i].display());
-        }
+    /**
+     * Searches for the value associated with the specified key in the hash map.
+     *
+     * @param key the key whose associated value is to be returned
+     * @return the value associated with the specified key, or null if the key does not exist
+     */
+    public V search(K key) {
+        int hash = computeHash(key);
+        Node<K, V> node = buckets[hash].findKey(key);
+        return node != null ? node.getValue() : null;
     }
 
-    public static class LinkedList {
-
-        private Node first;
-
-        public LinkedList() {
-            first = null;
+    /**
+     * Displays the contents of the hash map, showing each bucket and its key-value pairs.
+     */
+    public void display() {
+        for (int i = 0; i < hashSize; i++) {
+            System.out.printf("Bucket %d: %s%n", i, buckets[i].display());
         }
+    }
 
-        public void insert(int key) {
-            if (isEmpty()) {
-                first = new Node(key);
-                return;
-            }
+    /**
+     * A nested static class that represents a linked list used for separate chaining in the hash map.
+     *
+     * @param <K> the type of keys maintained by this linked list
+     * @param <V> the type of mapped values
+     */
+    public static class LinkedList<K, V> {
+        private Node<K, V> head;
 
-            Node temp = findEnd(first);
-            temp.setNext(new Node(key));
+        /**
+         * Inserts the specified key-value pair into the linked list.
+         * If the linked list is empty, the pair becomes the head.
+         * Otherwise, the pair is added to the end of the list.
+         *
+         * @param key   the key to be inserted
+         * @param value the value to be associated with the key
+         */
+        public void insert(K key, V value) {
+            Node<K, V> existingNode = findKey(key);
+            if (existingNode != null) {
+                existingNode.setValue(value); // Update the value, even if it's null
+            } else {
+                if (isEmpty()) {
+                    head = new Node<>(key, value);
+                } else {
+                    Node<K, V> temp = findEnd(head);
+                    temp.setNext(new Node<>(key, value));
+                }
+            }
         }
 
-        private Node findEnd(Node n) {
-            while (n.getNext() != null) {
-                n = n.getNext();
+        /**
+         * Finds the last node in the linked list.
+         *
+         * @param node the starting node
+         * @return the last node in the linked list
+         */
+        private Node<K, V> findEnd(Node<K, V> node) {
+            while (node.getNext() != null) {
+                node = node.getNext();
             }
-            return n;
+            return node;
         }
 
-        public Node findKey(int key) {
-            if (!isEmpty()) {
-                Node temp = first;
-                if (temp.getKey() == key) {
+        /**
+         * Finds the node associated with the specified key in the linked list.
+         *
+         * @param key the key to search for
+         * @return the node associated with the specified key, or null if not found
+         */
+        public Node<K, V> findKey(K key) {
+            Node<K, V> temp = head;
+            while (temp != null) {
+                if ((key == null && temp.getKey() == null) || (temp.getKey() != null && temp.getKey().equals(key))) {
                     return temp;
                 }
-
-                while ((temp = temp.getNext()) != null) {
-                    if (temp.getKey() == key) {
-                        return temp;
-                    }
-                }
+                temp = temp.getNext();
             }
             return null;
         }
 
-        public void delete(int key) {
-            if (!isEmpty()) {
-                if (first.getKey() == key) {
-                    Node next = first.next;
-                    first.next = null; // help GC
-                    first = next;
-                } else {
-                    delete(first, key);
-                }
+        /**
+         * Deletes the node associated with the specified key from the linked list.
+         * Handles the case where the key could be null.
+         *
+         * @param key the key whose associated node is to be deleted
+         */
+        public void delete(K key) {
+            if (isEmpty()) {
+                return;
             }
-        }
 
-        private void delete(Node n, int key) {
-            if (n.getNext().getKey() == key) {
-                if (n.getNext().getNext() == null) {
-                    n.setNext(null);
-                } else {
-                    n.setNext(n.getNext().getNext());
+            // Handle the case where the head node has the key to delete
+            if ((key == null && head.getKey() == null) || (head.getKey() != null && head.getKey().equals(key))) {
+                head = head.getNext();
+                return;
+            }
+
+            // Traverse the list to find and delete the node
+            Node<K, V> current = head;
+            while (current.getNext() != null) {
+                if ((key == null && current.getNext().getKey() == null) || (current.getNext().getKey() != null && current.getNext().getKey().equals(key))) {
+                    current.setNext(current.getNext().getNext());
+                    return;
                 }
-            } else {
-                delete(n.getNext(), key);
+                current = current.getNext();
             }
         }
 
+        /**
+         * Displays the contents of the linked list as a string.
+         *
+         * @return a string representation of the linked list
+         */
         public String display() {
-            return display(first);
+            return display(head);
         }
 
-        private String display(Node n) {
-            if (n == null) {
-                return "null";
-            } else {
-                return n.getKey() + "->" + display(n.getNext());
+        /**
+         * Constructs a string representation of the linked list non-recursively.
+         *
+         * @param node the starting node
+         * @return a string representation of the linked list starting from the given node
+         */
+        private String display(Node<K, V> node) {
+            StringBuilder sb = new StringBuilder();
+            while (node != null) {
+                sb.append(node.getKey()).append("=").append(node.getValue());
+                node = node.getNext();
+                if (node != null) {
+                    sb.append(" -> ");
+                }
             }
+            return sb.toString().isEmpty() ? "null" : sb.toString();
         }
 
+        /**
+         * Checks if the linked list is empty.
+         *
+         * @return true if the linked list is empty, false otherwise
+         */
         public boolean isEmpty() {
-            return first == null;
+            return head == null;
         }
     }
 
-    public static class Node {
+    /**
+     * A nested static class representing a node in the linked list.
+     *
+     * @param <K> the type of key maintained by this node
+     * @param <V> the type of value maintained by this node
+     */
+    public static class Node<K, V> {
+        private final K key;
+        private V value;
+        private Node<K, V> next;
 
-        private Node next;
-        private final int key;
-
-        public Node(int key) {
-            next = null;
+        /**
+         * Constructs a Node with the specified key and value.
+         *
+         * @param key   the key associated with this node
+         * @param value the value associated with this node
+         */
+        public Node(K key, V value) {
             this.key = key;
+            this.value = value;
         }
 
-        public Node getNext() {
-            return next;
+        /**
+         * Gets the key associated with this node.
+         *
+         * @return the key associated with this node
+         */
+        public K getKey() {
+            return key;
         }
 
-        public int getKey() {
-            return key;
+        /**
+         * Gets the value associated with this node.
+         *
+         * @return the value associated with this node
+         */
+        public V getValue() {
+            return value;
+        }
+
+        public void setValue(V value) { // This method allows updating the value
+            this.value = value;
+        }
+
+        /**
+         * Gets the next node in the linked list.
+         *
+         * @return the next node in the linked list
+         */
+        public Node<K, V> getNext() {
+            return next;
         }
 
-        public void setNext(Node next) {
+        /**
+         * Sets the next node in the linked list.
+         *
+         * @param next the next node to be linked
+         */
+        public void setNext(Node<K, V> next) {
             this.next = next;
         }
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
deleted file mode 100644
index 4d9b33b115c7..000000000000
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
+++ /dev/null
@@ -1,52 +0,0 @@
-package com.thealgorithms.datastructures.hashmap.hashing;
-
-import java.util.Scanner;
-
-public final class Main {
-    private Main() {
-    }
-
-    public static void main(String[] args) {
-        int choice;
-        int key;
-
-        HashMap h = new HashMap(7);
-        Scanner scan = new Scanner(System.in);
-
-        while (true) {
-            System.out.println("Enter your Choice :");
-            System.out.println("1. Add Key");
-            System.out.println("2. Delete Key");
-            System.out.println("3. Print Table");
-            System.out.println("4. Exit");
-
-            choice = scan.nextInt();
-
-            switch (choice) {
-            case 1:
-                System.out.println("Enter the Key: ");
-                key = scan.nextInt();
-                h.insertHash(key);
-                break;
-
-            case 2:
-                System.out.println("Enter the Key delete:  ");
-                key = scan.nextInt();
-                h.deleteHash(key);
-                break;
-
-            case 3:
-                System.out.println("Print table");
-                h.displayHashtable();
-                break;
-
-            case 4:
-                scan.close();
-                return;
-
-            default:
-                throw new IllegalArgumentException("Unexpected value: " + choice);
-            }
-        }
-    }
-}
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java
new file mode 100644
index 000000000000..3552bc1aa9c5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java
@@ -0,0 +1,146 @@
+package com.thealgorithms.datastructures.hashmap.hashing;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+public class HashMapTest {
+
+    @Test
+    public void testInsertAndSearch() {
+        HashMap<Integer, String> hashMap = new HashMap<>(10);
+        hashMap.insert(15, "Value15");
+        hashMap.insert(25, "Value25");
+        hashMap.insert(35, "Value35");
+
+        assertEquals("Value15", hashMap.search(15));
+        assertEquals("Value25", hashMap.search(25));
+        assertEquals("Value35", hashMap.search(35));
+        assertNull(hashMap.search(45));
+    }
+
+    @Test
+    public void testDelete() {
+        HashMap<Integer, String> hashMap = new HashMap<>(10);
+        hashMap.insert(15, "Value15");
+        hashMap.insert(25, "Value25");
+        hashMap.insert(35, "Value35");
+
+        assertEquals("Value25", hashMap.search(25));
+        hashMap.delete(25);
+        assertNull(hashMap.search(25));
+    }
+
+    @Test
+    public void testDisplay() {
+        HashMap<Integer, String> hashMap = new HashMap<>(5);
+        hashMap.insert(15, "Value15");
+        hashMap.insert(25, "Value25");
+        hashMap.insert(35, "Value35");
+        hashMap.display();
+    }
+
+    @Test
+    public void testInsertNullKey() {
+        HashMap<Integer, String> hashMap = new HashMap<>(10);
+        hashMap.insert(null, "NullValue");
+        assertEquals("NullValue", hashMap.search(null));
+    }
+
+    @Test
+    public void testInsertNullValue() {
+        HashMap<Integer, String> hashMap = new HashMap<>(10);
+        hashMap.insert(15, null);
+        assertNull(hashMap.search(15));
+    }
+
+    @Test
+    public void testUpdateExistingKey() {
+        HashMap<Integer, String> hashMap = new HashMap<>(10);
+        hashMap.insert(15, "Value15");
+        hashMap.insert(15, "UpdatedValue15");
+
+        assertEquals("UpdatedValue15", hashMap.search(15));
+    }
+
+    @Test
+    public void testHandleCollisions() {
+        HashMap<Integer, String> hashMap = new HashMap<>(3);
+        // These keys should collide if the hash function is modulo 3
+        hashMap.insert(1, "Value1");
+        hashMap.insert(4, "Value4");
+        hashMap.insert(7, "Value7");
+
+        assertEquals("Value1", hashMap.search(1));
+        assertEquals("Value4", hashMap.search(4));
+        assertEquals("Value7", hashMap.search(7));
+    }
+
+    @Test
+    public void testSearchInEmptyHashMap() {
+        HashMap<Integer, String> hashMap = new HashMap<>(10);
+        assertNull(hashMap.search(10));
+    }
+
+    @Test
+    public void testDeleteNonExistentKey() {
+        HashMap<Integer, String> hashMap = new HashMap<>(10);
+        hashMap.insert(15, "Value15");
+        hashMap.delete(25);
+
+        assertEquals("Value15", hashMap.search(15));
+        assertNull(hashMap.search(25));
+    }
+
+    @Test
+    public void testInsertLargeNumberOfElements() {
+        HashMap<Integer, String> hashMap = new HashMap<>(10);
+        for (int i = 0; i < 100; i++) {
+            hashMap.insert(i, "Value" + i);
+        }
+
+        for (int i = 0; i < 100; i++) {
+            assertEquals("Value" + i, hashMap.search(i));
+        }
+    }
+
+    @Test
+    public void testDeleteHeadOfBucket() {
+        HashMap<Integer, String> hashMap = new HashMap<>(3);
+        hashMap.insert(1, "Value1");
+        hashMap.insert(4, "Value4");
+        hashMap.insert(7, "Value7");
+
+        hashMap.delete(1);
+        assertNull(hashMap.search(1));
+        assertEquals("Value4", hashMap.search(4));
+        assertEquals("Value7", hashMap.search(7));
+    }
+
+    @Test
+    public void testDeleteTailOfBucket() {
+        HashMap<Integer, String> hashMap = new HashMap<>(3);
+        hashMap.insert(1, "Value1");
+        hashMap.insert(4, "Value4");
+        hashMap.insert(7, "Value7");
+
+        hashMap.delete(7);
+        assertNull(hashMap.search(7));
+        assertEquals("Value1", hashMap.search(1));
+        assertEquals("Value4", hashMap.search(4));
+    }
+
+    @Test
+    public void testDeleteMiddleElementOfBucket() {
+        HashMap<Integer, String> hashMap = new HashMap<>(3);
+        hashMap.insert(1, "Value1");
+        hashMap.insert(4, "Value4");
+        hashMap.insert(7, "Value7");
+
+        hashMap.delete(4);
+        assertNull(hashMap.search(4));
+        assertEquals("Value1", hashMap.search(1));
+        assertEquals("Value7", hashMap.search(7));
+    }
+}

From e2aaefebd5177cd99b69a2dea480b96d078cc58d Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Wed, 28 Aug 2024 22:34:46 +0200
Subject: [PATCH 0363/1338] refactor: `CountWords` (#5428)

* refactor: CountWords

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../com/thealgorithms/others/CountWords.java  | 25 +++++++----
 .../thealgorithms/others/CountWordsTest.java  | 44 ++++++++-----------
 2 files changed, 36 insertions(+), 33 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/CountWords.java b/src/main/java/com/thealgorithms/others/CountWords.java
index 26b9c50d928c..515c5d33fbf3 100644
--- a/src/main/java/com/thealgorithms/others/CountWords.java
+++ b/src/main/java/com/thealgorithms/others/CountWords.java
@@ -8,17 +8,26 @@ private CountWords() {
     }
 
     /**
-     * @brief counts the number of words in the input string
+     * Counts the number of words in the input string. Words are defined as sequences of
+     * characters separated by whitespace.
+     *
      * @param s the input string
-     * @return the number of words in the input string
+     * @return the number of words in the input string, or 0 if the string is null or empty
      */
     public static int wordCount(String s) {
         if (s == null || s.isEmpty()) {
             return 0;
         }
-        return s.trim().split("[\\s]+").length;
+        return s.trim().split("\\s+").length;
     }
 
+    /**
+     * Removes all special characters from the input string, leaving only alphanumeric characters
+     * and whitespace.
+     *
+     * @param s the input string
+     * @return a string containing only alphanumeric characters and whitespace
+     */
     private static String removeSpecialCharacters(String s) {
         StringBuilder sb = new StringBuilder();
         for (char c : s.toCharArray()) {
@@ -30,12 +39,12 @@ private static String removeSpecialCharacters(String s) {
     }
 
     /**
-     * counts the number of words in a sentence but ignores all potential
-     * non-alphanumeric characters that do not represent a word. runs in O(n)
-     * where n is the length of s
+     * Counts the number of words in a sentence, ignoring all non-alphanumeric characters that do
+     * not contribute to word formation. This method has a time complexity of O(n), where n is the
+     * length of the input string.
      *
-     * @param s String: sentence with word(s)
-     * @return int: number of words
+     * @param s the input string
+     * @return the number of words in the input string, with special characters removed, or 0 if the string is null
      */
     public static int secondaryWordCount(String s) {
         if (s == null) {
diff --git a/src/test/java/com/thealgorithms/others/CountWordsTest.java b/src/test/java/com/thealgorithms/others/CountWordsTest.java
index d5ebe654b325..17bb3aa692e7 100644
--- a/src/test/java/com/thealgorithms/others/CountWordsTest.java
+++ b/src/test/java/com/thealgorithms/others/CountWordsTest.java
@@ -2,36 +2,30 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.util.HashMap;
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class CountWordsTest {
-    @Test
-    public void testWordCount() {
-        HashMap<String, Integer> testCases = new HashMap<>();
-        testCases.put("", 0);
-        testCases.put(null, 0);
-        testCases.put("aaaa bbb cccc", 3);
-        testCases.put("note  extra     spaces   here", 4);
-        testCases.put(" a  b c d  e    ", 5);
 
-        for (final var tc : testCases.entrySet()) {
-            assertEquals(CountWords.wordCount(tc.getKey()), tc.getValue());
-        }
+    @ParameterizedTest
+    @MethodSource("wordCountTestCases")
+    void testWordCount(String input, int expectedCount) {
+        assertEquals(expectedCount, CountWords.wordCount(input));
     }
 
-    @Test
-    public void testSecondaryWordCount() {
-        HashMap<String, Integer> testCases = new HashMap<>();
-        testCases.put("", 0);
-        testCases.put(null, 0);
-        testCases.put("aaaa bbb cccc", 3);
-        testCases.put("this-is-one-word!", 1);
-        testCases.put("What, about, this? Hmmm----strange", 4);
-        testCases.put("word1 word-2 word-3- w?o,r.d.@!@#$&*()<>4", 4);
+    @ParameterizedTest
+    @MethodSource("secondaryWordCountTestCases")
+    void testSecondaryWordCount(String input, int expectedCount) {
+        assertEquals(expectedCount, CountWords.secondaryWordCount(input));
+    }
+
+    private static Stream<Arguments> wordCountTestCases() {
+        return Stream.of(Arguments.of("", 0), Arguments.of(null, 0), Arguments.of("aaaa bbb cccc", 3), Arguments.of("note  extra     spaces   here", 4), Arguments.of(" a  b c d  e    ", 5));
+    }
 
-        for (final var tc : testCases.entrySet()) {
-            assertEquals(CountWords.secondaryWordCount(tc.getKey()), tc.getValue());
-        }
+    private static Stream<Arguments> secondaryWordCountTestCases() {
+        return Stream.of(Arguments.of("", 0), Arguments.of(null, 0), Arguments.of("aaaa bbb cccc", 3), Arguments.of("this-is-one-word!", 1), Arguments.of("What, about, this? Hmmm----strange", 4), Arguments.of("word1 word-2 word-3- w?o,r.d.@!@#$&*()<>4", 4));
     }
 }

From c57e02dc856e61118d89609f34900ff6d4d0376c Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Thu, 29 Aug 2024 15:51:05 +0200
Subject: [PATCH 0364/1338] refactor: `DuplicateBrackets` (#5424)

refactor: DuplicateBrackets

Co-authored-by: alxkm <alx@alx.com>
---
 .../stacks/DuplicateBrackets.java             | 46 +++++++++++--------
 .../stacks/DuplicateBracketsTest.java         | 29 ++++++++++++
 2 files changed, 55 insertions(+), 20 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java b/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
index 482bda0a02a2..25d265232151 100644
--- a/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
+++ b/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java
@@ -1,37 +1,43 @@
 package com.thealgorithms.stacks;
 
-//  1. You are given a string exp representing an expression.
-// 2. Assume that the expression is balanced  i.e. the opening and closing brackets match with each
-// other.
-// 3. But, some of the pair of brackets maybe extra/needless.
-// 4. You are required to print true if you detect extra brackets and false otherwise.
-// e.g.'
-// ((a + b) + (c + d)) -> false
-// (a + b) + ((c + d)) -> true
 import java.util.Stack;
 
+/**
+ * Class for detecting unnecessary or redundant brackets in a mathematical expression.
+ * Assumes the expression is balanced (i.e., all opening brackets have matching closing brackets).
+ */
 public final class DuplicateBrackets {
     private DuplicateBrackets() {
     }
 
-    public static boolean check(String str) {
-        Stack<Character> st = new Stack<>();
+    /**
+     * Checks for extra or redundant brackets in a given expression.
+     *
+     * @param expression the string representing the expression to be checked
+     * @return true if there are extra or redundant brackets, false otherwise
+     * @throws IllegalArgumentException if the input string is null
+     */
+    public static boolean check(String expression) {
+        if (expression == null) {
+            throw new IllegalArgumentException("Input expression cannot be null.");
+        }
 
-        for (int i = 0; i < str.length(); i++) {
-            char ch = str.charAt(i);
+        Stack<Character> stack = new Stack<>();
+        for (int i = 0; i < expression.length(); i++) {
+            char ch = expression.charAt(i);
             if (ch == ')') {
-                if (st.peek() == '(') {
+                if (stack.isEmpty() || stack.peek() == '(') {
                     return true;
-                } else {
-                    while (st.size() > 0 && st.peek() != '(') {
-                        st.pop();
-                    }
-                    st.pop();
+                }
+                while (!stack.isEmpty() && stack.peek() != '(') {
+                    stack.pop();
+                }
+                if (!stack.isEmpty()) {
+                    stack.pop();
                 }
             } else {
-                st.push(ch);
+                stack.push(ch);
             }
-            // System.out.println(st);
         }
         return false;
     }
diff --git a/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java b/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java
new file mode 100644
index 000000000000..e2cc6acb8112
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class DuplicateBracketsTest {
+
+    @ParameterizedTest
+    @CsvSource({"'((a + b) + (c + d))'", "'(a + b)'", "'a + b'", "'('", "''"})
+    void testInputReturnsFalse(String input) {
+        assertFalse(DuplicateBrackets.check(input));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"'(a + b) + ((c + d))'", "'((a + b))'", "'((((a + b)))))'"})
+    void testInputReturnsTrue(String input) {
+        assertTrue(DuplicateBrackets.check(input));
+    }
+
+    @Test
+    void testInvalidInput() {
+        assertThrows(IllegalArgumentException.class, () -> DuplicateBrackets.check(null));
+    }
+}

From 9515d96ab6a229deaea118b1bc559daefec450f7 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 30 Aug 2024 00:13:30 +0200
Subject: [PATCH 0365/1338] Chore(deps): bump org.apache.commons:commons-lang3
 from 3.16.0 to 3.17.0 (#5437)

Bumps org.apache.commons:commons-lang3 from 3.16.0 to 3.17.0.

---
updated-dependencies:
- dependency-name: org.apache.commons:commons-lang3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 0d2d32e6dd1d..68bbb793f842 100644
--- a/pom.xml
+++ b/pom.xml
@@ -50,7 +50,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
-            <version>3.16.0</version>
+            <version>3.17.0</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>

From d189c3a719941b7d369da9572e75cc692e9bc494 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 30 Aug 2024 08:43:45 +0200
Subject: [PATCH 0366/1338] refactor: `LeastCommonMultiple` (#5435)

* refactor: LeastCommonMultiple

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../maths/LeastCommonMultiple.java            | 26 ++++-----------
 .../maths/LeastCommonMultipleTest.java        | 32 ++++++++-----------
 2 files changed, 19 insertions(+), 39 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java b/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
index db79340f0a99..9ec11e9b3220 100644
--- a/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
+++ b/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java
@@ -1,41 +1,27 @@
 package com.thealgorithms.maths;
 
-import java.util.Scanner;
-
 /**
  * Is a common mathematics concept to find the smallest value number
  * that can be divide using either number without having the remainder.
  * https://maticschool.blogspot.com/2013/11/find-least-common-multiple-lcm.html
  * @author LauKinHoong
  */
-
 public final class LeastCommonMultiple {
     private LeastCommonMultiple() {
     }
 
     /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        Scanner input = new Scanner(System.in);
-        System.out.println("Please enter first number >> ");
-        int num1 = input.nextInt();
-        System.out.println("Please enter second number >> ");
-        int num2 = input.nextInt();
-        System.out.println("The least common multiple of two numbers is >> " + lcm(num1, num2));
-        input.close();
-    }
-
-    /*
-     * get least common multiple from two number
+     * Finds the least common multiple of two numbers.
+     *
+     * @param num1 The first number.
+     * @param num2 The second number.
+     * @return The least common multiple of num1 and num2.
      */
     public static int lcm(int num1, int num2) {
         int high;
         int num3;
         int cmv = 0;
-        /*
-         * value selection for the numerator
-         */
+
         if (num1 > num2) {
             high = num1;
             num3 = num1;
diff --git a/src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java b/src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java
index d6baec2e97a7..73da509723c5 100644
--- a/src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java
+++ b/src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java
@@ -1,27 +1,21 @@
 package com.thealgorithms.maths;
 
-import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-public class LeastCommonMultipleTest {
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
-    /*
-     * Test for first number greater than second number
-     */
-    @Test
-    public void testForFirst() {
-        int result = LeastCommonMultiple.lcm(6, 8);
-        int expected = 24;
-        Assertions.assertEquals(result, expected);
+class LeastCommonMultipleTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testLcm(int num1, int num2, int expected) {
+        assertEquals(expected, LeastCommonMultiple.lcm(num1, num2));
     }
 
-    /*
-     * Test for second number greater than first number
-     */
-    @Test
-    public void testForSecond() {
-        int result = LeastCommonMultiple.lcm(8, 6);
-        int expected = 24;
-        Assertions.assertEquals(result, expected);
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(12, 18, 36), Arguments.of(5, 10, 10), Arguments.of(7, 3, 21), Arguments.of(21, 6, 42), Arguments.of(1, 1, 1), Arguments.of(8, 12, 24), Arguments.of(14, 35, 70), Arguments.of(15, 25, 75), Arguments.of(100, 25, 100), Arguments.of(0, 10, 0));
     }
 }

From 87cf89192bdc62ac40c71ff18207f36d254918e2 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 30 Aug 2024 08:50:14 +0200
Subject: [PATCH 0367/1338] style: use proper spelling (#5436)

checkstyle: fix typos, style

Co-authored-by: alxkm <alx@alx.com>
Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 pmd-exclude.properties                         |  2 +-
 ...iteGrapfDFS.java => BipartiteGraphDFS.java} |  4 ++--
 ...edlist.java => MergeKSortedLinkedList.java} |  2 +-
 .../thealgorithms/stacks/LargestRectangle.java |  6 +++---
 .../strings/ReverseWordsInString.java          |  1 -
 .../java/com/thealgorithms/strings/Upper.java  |  4 ++--
 .../stacks/LargestRectangleTest.java           | 18 +++++++++---------
 7 files changed, 18 insertions(+), 19 deletions(-)
 rename src/main/java/com/thealgorithms/datastructures/graphs/{BipartiteGrapfDFS.java => BipartiteGraphDFS.java} (97%)
 rename src/main/java/com/thealgorithms/datastructures/lists/{MergeKSortedLinkedlist.java => MergeKSortedLinkedList.java} (96%)

diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index 1e7a09549aca..f6ee88196962 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -12,7 +12,7 @@ com.thealgorithms.datastructures.crdt.LWWElementSet=UselessParentheses
 com.thealgorithms.datastructures.crdt.Pair=UnusedPrivateField
 com.thealgorithms.datastructures.graphs.AStar=UselessParentheses
 com.thealgorithms.datastructures.graphs.AdjacencyMatrixGraph=CollapsibleIfStatements,UnnecessaryFullyQualifiedName,UselessParentheses
-com.thealgorithms.datastructures.graphs.BipartiteGrapfDFS=CollapsibleIfStatements
+com.thealgorithms.datastructures.graphs.BipartiteGraphDFS=CollapsibleIfStatements
 com.thealgorithms.datastructures.graphs.Kruskal=UselessParentheses
 com.thealgorithms.datastructures.hashmap.hashing.HashMapCuckooHashing=UselessParentheses
 com.thealgorithms.datastructures.heaps.FibonacciHeap=UselessParentheses
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java b/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java
similarity index 97%
rename from src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
rename to src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java
index 4cc14bfd38de..e8d2b8fd0a04 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java
@@ -14,8 +14,8 @@
  *
  * Output : YES
  */
-public final class BipartiteGrapfDFS {
-    private BipartiteGrapfDFS() {
+public final class BipartiteGraphDFS {
+    private BipartiteGraphDFS() {
     }
 
     private static boolean bipartite(int v, ArrayList<ArrayList<Integer>> adj, int[] color, int node) {
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedlist.java b/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java
similarity index 96%
rename from src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedlist.java
rename to src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java
index ece178908e63..0eac20d2e9ad 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedlist.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java
@@ -7,7 +7,7 @@
 /**
  * @author Arun Pandey (https://github.com/pandeyarun709)
  */
-public class MergeKSortedLinkedlist {
+public class MergeKSortedLinkedList {
 
     /**
      * This function merge K sorted LinkedList
diff --git a/src/main/java/com/thealgorithms/stacks/LargestRectangle.java b/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
index 0404d9c99508..006e03632e63 100644
--- a/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
+++ b/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
@@ -11,7 +11,7 @@ public final class LargestRectangle {
     private LargestRectangle() {
     }
 
-    public static String largestRectanglehistogram(int[] heights) {
+    public static String largestRectangleHistogram(int[] heights) {
         int n = heights.length;
         int maxArea = 0;
         Stack<int[]> st = new Stack<>();
@@ -32,7 +32,7 @@ public static String largestRectanglehistogram(int[] heights) {
     }
 
     public static void main(String[] args) {
-        assert largestRectanglehistogram(new int[] {2, 1, 5, 6, 2, 3}).equals("10");
-        assert largestRectanglehistogram(new int[] {2, 4}).equals("4");
+        assert largestRectangleHistogram(new int[] {2, 1, 5, 6, 2, 3}).equals("10");
+        assert largestRectangleHistogram(new int[] {2, 4}).equals("4");
     }
 }
diff --git a/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java b/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java
index 5f9d27b4e9e2..7c22cd8a5df2 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java
@@ -13,7 +13,6 @@ private ReverseWordsInString() {
      * @param s the input string
      * @return A string created by reversing the order of the words in {@code s}
      */
-
     public static String reverseWordsInString(final String s) {
         var words = s.trim().split("\\s+");
         Collections.reverse(Arrays.asList(words));
diff --git a/src/main/java/com/thealgorithms/strings/Upper.java b/src/main/java/com/thealgorithms/strings/Upper.java
index 0fc87a9da318..fa9a408416ea 100644
--- a/src/main/java/com/thealgorithms/strings/Upper.java
+++ b/src/main/java/com/thealgorithms/strings/Upper.java
@@ -15,13 +15,13 @@ public static void main(String[] args) {
     }
 
     /**
-     * Converts all of the characters in this {@code String} to upper case
+     * Converts all the characters in this {@code String} to upper case
      *
      * @param s the string to convert
      * @return the {@code String}, converted to uppercase.
      */
     public static String toUpperCase(String s) {
-        if (s == null || "".equals(s)) {
+        if (s == null || s.isEmpty()) {
             return s;
         }
         char[] values = s.toCharArray();
diff --git a/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java b/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java
index 023f20a159f1..a54372adda0e 100644
--- a/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java
+++ b/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java
@@ -11,19 +11,19 @@ void testLargestRectangleHistogramWithTypicalCases() {
         // Typical case with mixed heights
         int[] heights = {2, 1, 5, 6, 2, 3};
         String expected = "10";
-        String result = LargestRectangle.largestRectanglehistogram(heights);
+        String result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
 
         // Another typical case with increasing heights
         heights = new int[] {2, 4};
         expected = "4";
-        result = LargestRectangle.largestRectanglehistogram(heights);
+        result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
 
         // Case with multiple bars of the same height
         heights = new int[] {4, 4, 4, 4};
         expected = "16";
-        result = LargestRectangle.largestRectanglehistogram(heights);
+        result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
     }
 
@@ -32,19 +32,19 @@ void testLargestRectangleHistogramWithEdgeCases() {
         // Edge case with an empty array
         int[] heights = {};
         String expected = "0";
-        String result = LargestRectangle.largestRectanglehistogram(heights);
+        String result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
 
         // Edge case with a single bar
         heights = new int[] {5};
         expected = "5";
-        result = LargestRectangle.largestRectanglehistogram(heights);
+        result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
 
         // Edge case with all bars of height 0
         heights = new int[] {0, 0, 0};
         expected = "0";
-        result = LargestRectangle.largestRectanglehistogram(heights);
+        result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
     }
 
@@ -56,7 +56,7 @@ void testLargestRectangleHistogramWithLargeInput() {
             heights[i] = 1;
         }
         String expected = "10000";
-        String result = LargestRectangle.largestRectanglehistogram(heights);
+        String result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
     }
 
@@ -65,13 +65,13 @@ void testLargestRectangleHistogramWithComplexCases() {
         // Complex case with a mix of heights
         int[] heights = {6, 2, 5, 4, 5, 1, 6};
         String expected = "12";
-        String result = LargestRectangle.largestRectanglehistogram(heights);
+        String result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
 
         // Case with a peak in the middle
         heights = new int[] {2, 1, 5, 6, 2, 3, 1};
         expected = "10";
-        result = LargestRectangle.largestRectanglehistogram(heights);
+        result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
     }
 }

From 14916e692f3e685452fb93929285061cdda459d4 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 30 Aug 2024 09:49:55 +0200
Subject: [PATCH 0368/1338] refactor: `WordLadder` (#5434)

* refactor: WordLadder

* refactor: fix redundant check

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../com/thealgorithms/strings/WordLadder.java | 78 ++++++-------------
 .../thealgorithms/strings/WordLadderTest.java | 10 +++
 2 files changed, 34 insertions(+), 54 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/WordLadder.java b/src/main/java/com/thealgorithms/strings/WordLadder.java
index 707fdfc67d85..084a682b04a7 100644
--- a/src/main/java/com/thealgorithms/strings/WordLadder.java
+++ b/src/main/java/com/thealgorithms/strings/WordLadder.java
@@ -4,58 +4,28 @@
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Queue;
+import java.util.Set;
 
-/*
-    **Problem Statement:**
-    A transformation sequence from word beginWord to word endWord using a dictionary wordList is a
-   sequence of words beginWord -> s1 -> s2 -> ... -> sk such that:
-
-    Every adjacent pair of words differs by a single letter.
-    Every si for 1 <= i <= k is in wordList. Note that beginWord does not need to be in wordList.
-    sk == endWord
-    Given two words, beginWord and endWord, and a dictionary wordList, return the number of words in
-   the shortest transformation sequence from beginWord to endWord, or 0 if no such sequence exists.
-
-    **Example 1:**
-    Input: beginWord = "hit", endWord = "cog", wordList = ["hot","dot","dog","lot","log","cog"]
-    Output: 5
-    Explanation: One shortest transformation sequence is "hit" -> "hot" -> "dot" -> "dog" -> cog",
-   which is 5 words long.
-
-    **Example 2:**
-    Input: beginWord = "hit", endWord = "cog", wordList = ["hot","dot","dog","lot","log"]
-    Output: 0
-    Explanation: The endWord "cog" is not in wordList, therefore there is no valid transformation
-   sequence.
-
-    **Constraints:**
-    1 <= beginWord.length <= 10
-    endWord.length == beginWord.length
-    1 <= wordList.length <= 5000
-    wordList[i].length == beginWord.length
-    beginWord, endWord, and wordList[i] consist of lowercase English letters.
-    beginWord != endWord
-    All the words in wordList are unique.
+/**
+ * Class to find the shortest transformation sequence from a beginWord to an endWord using a dictionary of words.
+ * A transformation sequence is a sequence of words where each adjacent pair differs by exactly one letter.
  */
-
-final class WordLadder {
+public final class WordLadder {
     private WordLadder() {
     }
 
     /**
-     * This function finds the ladderLength
+     * Finds the shortest transformation sequence from beginWord to endWord.
      *
-     * @param beginWord: Starting word of the ladder
-     * @param endWord: Ending word of the ladder
-     * @param wordList: This list contains the words which needs to be included
-     * in ladder.
-     * @return ladderLength: This function will return the ladderLength(level)
-     * if the endword is there. Otherwise, will return the length as 0.
+     * @param beginWord the starting word of the transformation sequence
+     * @param endWord the target word of the transformation sequence
+     * @param wordList a list of words that can be used in the transformation sequence
+     * @return the number of words in the shortest transformation sequence, or 0 if no such sequence exists
      */
     public static int ladderLength(String beginWord, String endWord, List<String> wordList) {
-        HashSet<String> set = new HashSet<>(wordList);
+        Set<String> wordSet = new HashSet<>(wordList);
 
-        if (!set.contains(endWord)) {
+        if (!wordSet.contains(endWord)) {
             return 0;
         }
 
@@ -66,25 +36,25 @@ public static int ladderLength(String beginWord, String endWord, List<String> wo
         while (!queue.isEmpty()) {
             int size = queue.size();
             for (int i = 0; i < size; i++) {
-                String curr = queue.poll();
-                char[] wordsChars = curr.toCharArray();
-                for (int j = 0; j < wordsChars.length; j++) {
-                    char originalChars = wordsChars[j];
+                String currentWord = queue.poll();
+                char[] currentWordChars = currentWord.toCharArray();
+                for (int j = 0; j < currentWordChars.length; j++) {
+                    char originalChar = currentWordChars[j];
                     for (char c = 'a'; c <= 'z'; c++) {
-                        if (wordsChars[j] == c) {
+                        if (currentWordChars[j] == c) {
                             continue;
                         }
-                        wordsChars[j] = c;
-                        String transformedWord = String.valueOf(wordsChars);
-                        if (transformedWord.equals(endWord)) {
+                        currentWordChars[j] = c;
+                        String newWord = new String(currentWordChars);
+
+                        if (newWord.equals(endWord)) {
                             return level + 1;
                         }
-                        if (set.contains(transformedWord)) {
-                            set.remove(transformedWord);
-                            queue.offer(transformedWord);
+                        if (wordSet.remove(newWord)) {
+                            queue.offer(newWord);
                         }
                     }
-                    wordsChars[j] = originalChars;
+                    currentWordChars[j] = originalChar;
                 }
             }
             level++;
diff --git a/src/test/java/com/thealgorithms/strings/WordLadderTest.java b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
index c59f2d8b31be..d933ebeddc53 100644
--- a/src/test/java/com/thealgorithms/strings/WordLadderTest.java
+++ b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
@@ -5,6 +5,8 @@
 import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class WordLadderTest {
 
@@ -38,4 +40,12 @@ public void testWordLadder2() {
         List<String> wordList2 = Arrays.asList("hot", "dot", "dog", "lot", "log");
         assertEquals(WordLadder.ladderLength("hit", "cog", wordList2), 0);
     }
+
+    @ParameterizedTest
+    @CsvSource({"'a', 'c', 'b,c', 2", "'a', 'c', 'a', 0", "'a', 'a', 'a', 0", "'ab', 'cd', 'ad,bd,cd', 3", "'a', 'd', 'b,c,d', 2", "'a', 'd', 'b,c,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,d', 2"})
+    void testLadderLength(String beginWord, String endWord, String wordListStr, int expectedLength) {
+        List<String> wordList = List.of(wordListStr.split(","));
+        int result = WordLadder.ladderLength(beginWord, endWord, wordList);
+        assertEquals(expectedLength, result);
+    }
 }

From cd38531b0d618c2b8e8d4889a56f1180ac02ef51 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 30 Aug 2024 09:55:18 +0200
Subject: [PATCH 0369/1338] refactor: `SubsetSum` (#5432)

* refactor: SubsetSum

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../dynamicprogramming/SubsetSum.java         | 46 +++++++------------
 .../dynamicprogramming/SubsetSumTest.java     | 24 ++++++++++
 2 files changed, 40 insertions(+), 30 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java
index 087d9ac2c7e7..3dd41d2fdc0f 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java
@@ -5,46 +5,32 @@ private SubsetSum() {
     }
 
     /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        int[] arr = new int[] {50, 4, 10, 15, 34};
-        assert subsetSum(arr, 64);
-        /* 4 + 10 + 15 + 34 = 64 */
-        assert subsetSum(arr, 99);
-        /* 50 + 15 + 34 = 99 */
-        assert !subsetSum(arr, 5);
-        assert !subsetSum(arr, 66);
-    }
-
-    /**
-     * Test if a set of integers contains a subset that sum to a given integer.
+     * Test if a set of integers contains a subset that sums to a given integer.
      *
-     * @param arr the array contains integers.
-     * @param sum target sum of subset.
-     * @return {@code true} if subset exists, otherwise {@code false}.
+     * @param arr the array containing integers.
+     * @param sum the target sum of the subset.
+     * @return {@code true} if a subset exists that sums to the given value, otherwise {@code false}.
      */
     public static boolean subsetSum(int[] arr, int sum) {
         int n = arr.length;
-        boolean[][] isSum = new boolean[n + 2][sum + 1];
+        boolean[][] isSum = new boolean[n + 1][sum + 1];
 
-        isSum[n + 1][0] = true;
-        for (int i = 1; i <= sum; i++) {
-            isSum[n + 1][i] = false;
+        // Initialize the first column to true since a sum of 0 can always be achieved with an empty subset.
+        for (int i = 0; i <= n; i++) {
+            isSum[i][0] = true;
         }
 
-        for (int i = n; i > 0; i--) {
-            isSum[i][0] = true;
-            for (int j = 1; j <= arr[i - 1] - 1; j++) {
-                if (j <= sum) {
-                    isSum[i][j] = isSum[i + 1][j];
+        // Fill the subset sum matrix
+        for (int i = 1; i <= n; i++) {
+            for (int j = 1; j <= sum; j++) {
+                if (arr[i - 1] <= j) {
+                    isSum[i][j] = isSum[i - 1][j] || isSum[i - 1][j - arr[i - 1]];
+                } else {
+                    isSum[i][j] = isSum[i - 1][j];
                 }
             }
-            for (int j = arr[i - 1]; j <= sum; j++) {
-                isSum[i][j] = (isSum[i + 1][j] || isSum[i + 1][j - arr[i - 1]]);
-            }
         }
 
-        return isSum[1][sum];
+        return isSum[n][sum];
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java
new file mode 100644
index 000000000000..1ae4e71232f0
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java
@@ -0,0 +1,24 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class SubsetSumTest {
+
+    record TestCase(int[] arr, int sum, boolean expected) {
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testSubsetSum(TestCase testCase) {
+        assertEquals(testCase.expected(), SubsetSum.subsetSum(testCase.arr(), testCase.sum()));
+    }
+
+    private static Stream<TestCase> provideTestCases() {
+        return Stream.of(new TestCase(new int[] {50, 4, 10, 15, 34}, 64, true), new TestCase(new int[] {50, 4, 10, 15, 34}, 99, true), new TestCase(new int[] {50, 4, 10, 15, 34}, 5, false), new TestCase(new int[] {50, 4, 10, 15, 34}, 66, false), new TestCase(new int[] {}, 0, true),
+            new TestCase(new int[] {1, 2, 3}, 6, true), new TestCase(new int[] {1, 2, 3}, 7, false), new TestCase(new int[] {3, 34, 4, 12, 5, 2}, 9, true));
+    }
+}

From c5b72816f35f2a4d4e6627ddac7fc3889d5052e4 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 30 Aug 2024 10:03:43 +0200
Subject: [PATCH 0370/1338] refactor:
 `MaximumSumOfDistinctSubarraysWithLengthK` (#5433)

* refactor: MaximumSumOfDistinctSubarraysWithLengthK

* checkstyle: fix formatting

* checkstyle: fix formatting

* checkstyle: fix formatting

---------

Co-authored-by: alxkm <alx@alx.com>
---
 ...imumSumOfDistinctSubarraysWithLengthK.java | 77 +++++++++----------
 ...SumOfDistinctSubarraysWithLengthKTest.java | 32 +++-----
 2 files changed, 47 insertions(+), 62 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java b/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
index 5aa25812dcc2..c05f1af4e327 100644
--- a/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
+++ b/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
@@ -1,55 +1,53 @@
 package com.thealgorithms.others;
 
 import java.util.HashSet;
+import java.util.Set;
 
-/*
-References: https://en.wikipedia.org/wiki/Streaming_algorithm
-* In this model, the function of interest is computing over a fixed-size window in the stream. As the stream progresses,
-* items from the end of the window are removed from consideration while new items from the stream take their place.
-* @author Swarga-codes (https://github.com/Swarga-codes)
-*/
+/**
+ * References: https://en.wikipedia.org/wiki/Streaming_algorithm
+ *
+ * This model involves computing the maximum sum of subarrays of a fixed size \( K \) from a stream of integers.
+ * As the stream progresses, elements from the end of the window are removed, and new elements from the stream are added.
+ *
+ * @author Swarga-codes (https://github.com/Swarga-codes)
+ */
 public final class MaximumSumOfDistinctSubarraysWithLengthK {
     private MaximumSumOfDistinctSubarraysWithLengthK() {
     }
-    /*
-     * Returns the maximum sum of subarray of size K consisting of distinct
-     * elements.
-     *
-     * @param k size of the subarray which should be considered from the given
-     * array.
+
+    /**
+     * Finds the maximum sum of a subarray of size K consisting of distinct elements.
      *
-     * @param nums is the array from which we would be finding the required
-     * subarray.
+     * @param k The size of the subarray.
+     * @param nums The array from which subarrays will be considered.
      *
-     * @return the maximum sum of distinct subarray of size K.
+     * @return The maximum sum of any distinct-element subarray of size K. If no such subarray exists, returns 0.
      */
     public static long maximumSubarraySum(int k, int... nums) {
         if (nums.length < k) {
             return 0;
         }
-        long max = 0; // this will store the max sum which will be our result
-        long s = 0; // this will store the sum of every k elements which can be used to compare with
-                    // max
-        HashSet<Integer> set = new HashSet<>(); // this can be used to store unique elements in our subarray
-        // Looping through k elements to get the sum of first k elements
+        long masSum = 0; // Variable to store the maximum sum of distinct subarrays
+        long currentSum = 0; // Variable to store the sum of the current subarray
+        Set<Integer> currentSet = new HashSet<>(); // Set to track distinct elements in the current subarray
+
+        // Initialize the first window
         for (int i = 0; i < k; i++) {
-            s += nums[i];
-            set.add(nums[i]);
+            currentSum += nums[i];
+            currentSet.add(nums[i]);
         }
-        // Checking if the first kth subarray contains unique elements or not if so then
-        // we assign that to max
-        if (set.size() == k) {
-            max = s;
+        // If the first window contains distinct elements, update maxSum
+        if (currentSet.size() == k) {
+            masSum = currentSum;
         }
-        // Looping through the rest of the array to find different subarrays and also
-        // utilising the sliding window algorithm to find the sum
-        // in O(n) time complexity
+        // Slide the window across the array
         for (int i = 1; i < nums.length - k + 1; i++) {
-            s = s - nums[i - 1];
-            s = s + nums[i + k - 1];
+            // Update the sum by removing the element that is sliding out and adding the new element
+            currentSum = currentSum - nums[i - 1];
+            currentSum = currentSum + nums[i + k - 1];
             int j = i;
             boolean flag = false; // flag value which says that the subarray contains distinct elements
-            while (j < i + k && set.size() < k) {
+            while (j < i + k && currentSet.size() < k) {
                 if (nums[i - 1] == nums[j]) {
                     flag = true;
                     break;
@@ -58,17 +56,14 @@ public static long maximumSubarraySum(int k, int... nums) {
                 }
             }
             if (!flag) {
-                set.remove(nums[i - 1]);
+                currentSet.remove(nums[i - 1]);
             }
-            set.add(nums[i + k - 1]);
-            // if the subarray contains distinct elements then we compare and update the max
-            // value
-            if (set.size() == k) {
-                if (max < s) {
-                    max = s;
-                }
+            currentSet.add(nums[i + k - 1]);
+            // If the current window has distinct elements, compare and possibly update maxSum
+            if (currentSet.size() == k && masSum < currentSum) {
+                masSum = currentSum;
             }
         }
-        return max; // the final maximum sum
+        return masSum; // the final maximum sum
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java b/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
index a8e168ffa13a..f360e3f53546 100644
--- a/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
+++ b/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
@@ -2,31 +2,21 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class MaximumSumOfDistinctSubarraysWithLengthKTest {
-    @Test
-    public void sampleTestCase1() {
-        assertEquals(15, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(3, 1, 5, 4, 2, 9, 9, 9));
-    }
-
-    @Test
-    public void sampleTestCase2() {
-        assertEquals(0, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(3, 4, 4, 4));
-    }
-
-    @Test
-    public void sampleTestCase3() {
-        assertEquals(12, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(3, 9, 9, 9, 1, 2, 3));
-    }
 
-    @Test
-    public void edgeCase1() {
-        assertEquals(0, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(0, 9, 9, 9));
+    @ParameterizedTest
+    @MethodSource("inputStream")
+    void testMaximumSubarraySum(int expected, int k, int[] arr) {
+        assertEquals(expected, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(k, arr));
     }
 
-    @Test
-    public void edgeCase2() {
-        assertEquals(0, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(5, 9, 9, 9));
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of(15, 3, new int[] {1, 5, 4, 2, 9, 9, 9}), Arguments.of(0, 3, new int[] {4, 4, 4}), Arguments.of(12, 3, new int[] {9, 9, 9, 1, 2, 3}), Arguments.of(0, 0, new int[] {9, 9, 9}), Arguments.of(0, 5, new int[] {9, 9, 9}), Arguments.of(9, 1, new int[] {9, 2, 3, 7}),
+            Arguments.of(15, 5, new int[] {1, 2, 3, 4, 5}), Arguments.of(6, 3, new int[] {-1, 2, 3, 1, -2, 4}), Arguments.of(10, 1, new int[] {10}), Arguments.of(0, 2, new int[] {7, 7, 7, 7}), Arguments.of(0, 3, new int[] {}), Arguments.of(0, 10, new int[] {1, 2, 3}));
     }
 }

From f8ff6af893b4e59e0a4cdaea1e01684031192dfb Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 30 Aug 2024 10:12:31 +0200
Subject: [PATCH 0371/1338] refactor: `BoardPath` (#5431)

refactor: BoardPath

Co-authored-by: alxkm <alx@alx.com>
---
 .../dynamicprogramming/BoardPath.java         | 64 ++++++++-----------
 .../dynamicprogramming/BoardPathTest.java     | 33 ++++++++++
 2 files changed, 58 insertions(+), 39 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java b/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java
index b041cfc478d6..cd761f96019c 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java
@@ -1,46 +1,16 @@
 package com.thealgorithms.dynamicprogramming;
 
-/*
-* this is an important Algo in which
-* we have starting and ending of board and we have to reach
-* we have to count no. of ways
-* that help to reach end point i.e number by rolling dice
-* which have 1 to 6 digits
-
-Test Case:
-here target is 10
-
-int n=10;
-                startAlgo();
-                System.out.println(bpR(0,n));
-                System.out.println(endAlgo()+"ms");
-                int[] strg=new int [n+1];
-                startAlgo();
-                System.out.println(bpRS(0,n,strg));
-                System.out.println(endAlgo()+"ms");
-                startAlgo();
-                System.out.println(bpIS(0,n,strg));
-                System.out.println(endAlgo()+"ms");
-
-
-
- */
 public final class BoardPath {
     private BoardPath() {
     }
 
-    public static long startTime;
-    public static long endTime;
-
-    public static void startAlgo() {
-        startTime = System.currentTimeMillis();
-    }
-
-    public static long endAlgo() {
-        endTime = System.currentTimeMillis();
-        return endTime - startTime;
-    }
-
+    /**
+     * Recursive solution without memoization
+     *
+     * @param start - the current position
+     * @param end   - the target position
+     * @return the number of ways to reach the end from the start
+     */
     public static int bpR(int start, int end) {
         if (start == end) {
             return 1;
@@ -54,6 +24,14 @@ public static int bpR(int start, int end) {
         return count;
     }
 
+    /**
+     * Recursive solution with memoization
+     *
+     * @param curr - the current position
+     * @param end  - the target position
+     * @param strg - memoization array
+     * @return the number of ways to reach the end from the start
+     */
     public static int bpRS(int curr, int end, int[] strg) {
         if (curr == end) {
             return 1;
@@ -71,15 +49,23 @@ public static int bpRS(int curr, int end, int[] strg) {
         return count;
     }
 
+    /**
+     * Iterative solution with tabulation
+     *
+     * @param curr - the current position (always starts from 0)
+     * @param end  - the target position
+     * @param strg - memoization array
+     * @return the number of ways to reach the end from the start
+     */
     public static int bpIS(int curr, int end, int[] strg) {
         strg[end] = 1;
         for (int i = end - 1; i >= 0; i--) {
             int count = 0;
-            for (int dice = 1; dice <= 6 && dice + i < strg.length; dice++) {
+            for (int dice = 1; dice <= 6 && dice + i <= end; dice++) {
                 count += strg[i + dice];
             }
             strg[i] = count;
         }
-        return strg[0];
+        return strg[curr];
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java
new file mode 100644
index 000000000000..a704620e92da
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class BoardPathTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testBpR(int start, int end, int expected) {
+        assertEquals(expected, BoardPath.bpR(start, end));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testBpRS(int start, int end, int expected) {
+        assertEquals(expected, BoardPath.bpRS(start, end, new int[end + 1]));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testBpIS(int start, int end, int expected) {
+        assertEquals(expected, BoardPath.bpIS(start, end, new int[end + 1]));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(0, 10, 492), Arguments.of(0, 5, 16), Arguments.of(0, 6, 32), Arguments.of(0, 3, 4), Arguments.of(0, 1, 1));
+    }
+}

From b0de93b3cef1eadb0e92e88f53d556b3b08d2cc3 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Fri, 30 Aug 2024 11:58:24 +0200
Subject: [PATCH 0372/1338] refactor: change packages (#5430)

* refactor: change package

* refactor: fix name

---------

Co-authored-by: alxkm <alx@alx.com>
---
 .../graphs}/FordFulkerson.java                              | 2 +-
 .../ShortestCommonSupersequenceLength.java                  | 4 ++--
 .../com/thealgorithms/{others => maths}/EulersFunction.java | 2 +-
 .../{others => maths}/SieveOfEratosthenes.java              | 2 +-
 .../java/com/thealgorithms/{others => strings}/KMP.java     | 2 +-
 .../com/thealgorithms/{others => strings}/RabinKarp.java    | 2 +-
 .../graphs}/FordFulkersonTest.java                          | 2 +-
 ...Test.java => ShortestCommonSupersequenceLengthTest.java} | 6 +++---
 .../thealgorithms/{others => maths}/EulersFunctionTest.java | 2 +-
 .../{others => maths}/SieveOfEratosthenesTest.java          | 2 +-
 10 files changed, 13 insertions(+), 13 deletions(-)
 rename src/main/java/com/thealgorithms/{dynamicprogramming => datastructures/graphs}/FordFulkerson.java (97%)
 rename src/main/java/com/thealgorithms/{others => maths}/EulersFunction.java (97%)
 rename src/main/java/com/thealgorithms/{others => maths}/SieveOfEratosthenes.java (98%)
 rename src/main/java/com/thealgorithms/{others => strings}/KMP.java (97%)
 rename src/main/java/com/thealgorithms/{others => strings}/RabinKarp.java (98%)
 rename src/test/java/com/thealgorithms/{dynamicprogramming => datastructures/graphs}/FordFulkersonTest.java (98%)
 rename src/test/java/com/thealgorithms/dynamicprogramming/{ShortestCommonSuperSequenceLengthTest.java => ShortestCommonSupersequenceLengthTest.java} (70%)
 rename src/test/java/com/thealgorithms/{others => maths}/EulersFunctionTest.java (97%)
 rename src/test/java/com/thealgorithms/{others => maths}/SieveOfEratosthenesTest.java (98%)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java b/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java
similarity index 97%
rename from src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
rename to src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java
index 76995f1ce37e..af2665cfaebb 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.dynamicprogramming;
+package com.thealgorithms.datastructures.graphs;
 
 import java.util.LinkedList;
 import java.util.Queue;
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java b/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
index 3ea440caf508..56129dcdbb09 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java
@@ -5,8 +5,8 @@
  * supersequence of two given strings. The shortest supersequence is the smallest string
  * that contains both given strings as subsequences.
  */
-final class ShortestCommonSuperSequenceLength {
-    private ShortestCommonSuperSequenceLength() {
+final class ShortestCommonSupersequenceLength {
+    private ShortestCommonSupersequenceLength() {
     }
 
     /**
diff --git a/src/main/java/com/thealgorithms/others/EulersFunction.java b/src/main/java/com/thealgorithms/maths/EulersFunction.java
similarity index 97%
rename from src/main/java/com/thealgorithms/others/EulersFunction.java
rename to src/main/java/com/thealgorithms/maths/EulersFunction.java
index 7a6f49d41758..3a6bc8756681 100644
--- a/src/main/java/com/thealgorithms/others/EulersFunction.java
+++ b/src/main/java/com/thealgorithms/maths/EulersFunction.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.maths;
 
 /**
  * Utility class for computing
diff --git a/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java b/src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java
similarity index 98%
rename from src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java
rename to src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java
index 6a3412500d11..f22d22e8c6af 100644
--- a/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java
+++ b/src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.maths;
 
 import java.util.Arrays;
 
diff --git a/src/main/java/com/thealgorithms/others/KMP.java b/src/main/java/com/thealgorithms/strings/KMP.java
similarity index 97%
rename from src/main/java/com/thealgorithms/others/KMP.java
rename to src/main/java/com/thealgorithms/strings/KMP.java
index 73eaf2fc9beb..07d3b0415006 100644
--- a/src/main/java/com/thealgorithms/others/KMP.java
+++ b/src/main/java/com/thealgorithms/strings/KMP.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 /**
  * Implementation of Knuth–Morris–Pratt algorithm Usage: see the main function
diff --git a/src/main/java/com/thealgorithms/others/RabinKarp.java b/src/main/java/com/thealgorithms/strings/RabinKarp.java
similarity index 98%
rename from src/main/java/com/thealgorithms/others/RabinKarp.java
rename to src/main/java/com/thealgorithms/strings/RabinKarp.java
index cecf24e09b4a..bb8df3358453 100644
--- a/src/main/java/com/thealgorithms/others/RabinKarp.java
+++ b/src/main/java/com/thealgorithms/strings/RabinKarp.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 import java.util.Scanner;
 
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/FordFulkersonTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java
similarity index 98%
rename from src/test/java/com/thealgorithms/dynamicprogramming/FordFulkersonTest.java
rename to src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java
index d4d38ed5ccde..908296aab5c1 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/FordFulkersonTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.dynamicprogramming;
+package com.thealgorithms.datastructures.graphs;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSuperSequenceLengthTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLengthTest.java
similarity index 70%
rename from src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSuperSequenceLengthTest.java
rename to src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLengthTest.java
index 007e71e268ab..8f0fd79f18a4 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSuperSequenceLengthTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLengthTest.java
@@ -5,10 +5,10 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
 
-public class ShortestCommonSuperSequenceLengthTest {
+public class ShortestCommonSupersequenceLengthTest {
     @ParameterizedTest
     @CsvSource({"AGGTAB, GXTXAYB, 9", "ABC, ABC, 3", "ABC, DEF, 6", "'', ABC, 3", "ABCD, AB, 4", "ABC, BCD, 4", "A, B, 2"})
-    void testShortestSuperSequence(String input1, String input2, int expected) {
-        assertEquals(expected, ShortestCommonSuperSequenceLength.shortestSuperSequence(input1, input2));
+    void testShortestSupersequence(String input1, String input2, int expected) {
+        assertEquals(expected, ShortestCommonSupersequenceLength.shortestSuperSequence(input1, input2));
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/EulersFunctionTest.java b/src/test/java/com/thealgorithms/maths/EulersFunctionTest.java
similarity index 97%
rename from src/test/java/com/thealgorithms/others/EulersFunctionTest.java
rename to src/test/java/com/thealgorithms/maths/EulersFunctionTest.java
index 655c67c83aaa..9048a711d0d6 100644
--- a/src/test/java/com/thealgorithms/others/EulersFunctionTest.java
+++ b/src/test/java/com/thealgorithms/maths/EulersFunctionTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.maths;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
diff --git a/src/test/java/com/thealgorithms/others/SieveOfEratosthenesTest.java b/src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java
similarity index 98%
rename from src/test/java/com/thealgorithms/others/SieveOfEratosthenesTest.java
rename to src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java
index 207c51465c99..ebbd5df712fc 100644
--- a/src/test/java/com/thealgorithms/others/SieveOfEratosthenesTest.java
+++ b/src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.maths;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;

From b396a9790ea2bd09daf1e3a14f8c3eefb37f1aa5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 30 Aug 2024 23:47:39 +0200
Subject: [PATCH 0373/1338] Chore(deps): bump com.puppycrawl.tools:checkstyle
 from 10.18.0 to 10.18.1 (#5438)

Chore(deps): bump com.puppycrawl.tools:checkstyle

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.18.0 to 10.18.1.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.18.0...checkstyle-10.18.1)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 68bbb793f842..96fd6e124704 100644
--- a/pom.xml
+++ b/pom.xml
@@ -118,7 +118,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.18.0</version>
+                    <version>10.18.1</version>
                     </dependency>
                 </dependencies>
             </plugin>

From a5b083cab0e03de2e7a4c36ec17be932e423178b Mon Sep 17 00:00:00 2001
From: SOZEL <80200848+TruongNhanNguyen@users.noreply.github.com>
Date: Mon, 2 Sep 2024 03:25:34 +0700
Subject: [PATCH 0374/1338] Add SplayTree (#5142)

---
 DIRECTORY.md                                  |  94 ++++-
 .../datastructures/trees/SplayTree.java       | 324 ++++++++++++++++++
 .../datastructures/trees/SplayTreeTest.java   | 113 ++++++
 3 files changed, 513 insertions(+), 18 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/trees/SplayTree.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 30b107a177fb..bbcee88e52be 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -53,6 +53,7 @@
             * [SimpleSubCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/SimpleSubCipher.java)
             * [Vigenere](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Vigenere.java)
           * conversions
+            * [AffineConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AffineConverter.java)
             * [AnyBaseToAnyBase](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java)
             * [AnyBaseToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java)
             * [AnytoAny](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AnytoAny.java)
@@ -61,7 +62,7 @@
             * [BinaryToOctal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java)
             * [DecimalToAnyBase](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java)
             * [DecimalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java)
-            * [DecimalToHexaDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToHexaDecimal.java)
+            * [DecimalToHexadecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToHexadecimal.java)
             * [DecimalToOctal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java)
             * [HexaDecimalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java)
             * [HexaDecimalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java)
@@ -73,6 +74,8 @@
             * [RgbHsvConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java)
             * [RomanToInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/RomanToInteger.java)
             * [TurkishToLatinConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java)
+            * [UnitConversions](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/UnitConversions.java)
+            * [UnitsConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/UnitsConverter.java)
           * datastructures
             * bags
               * [Bag](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/bags/Bag.java)
@@ -99,12 +102,13 @@
             * graphs
               * [AStar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java)
               * [BellmanFord](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java)
-              * [BipartiteGrapfDFS](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java)
+              * [BipartiteGraphDFS](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java)
               * [BoruvkaAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithm.java)
               * [ConnectedComponent](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java)
               * [Cycles](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java)
-              * [DIJSKSTRAS ALGORITHM](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/DIJSKSTRAS_ALGORITHM.java)
+              * [DijkstraAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java)
               * [FloydWarshall](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java)
+              * [FordFulkerson](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java)
               * [Graphs](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java)
               * [HamiltonianCycle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java)
               * [KahnsAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java)
@@ -122,7 +126,6 @@
                 * [HashMapCuckooHashing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java)
                 * [Intersection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java)
                 * [LinearProbingHashMap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java)
-                * [Main](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java)
                 * [MainCuckooHashing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java)
                 * [MajorityElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java)
                 * [Map](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Map.java)
@@ -142,7 +145,7 @@
               * [CreateAndDetectLoop](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java)
               * [CursorLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java)
               * [DoublyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java)
-              * [MergeKSortedLinkedlist](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedlist.java)
+              * [MergeKSortedLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java)
               * [MergeSortedArrayList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java)
               * [MergeSortedSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java)
               * [QuickSortLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java)
@@ -155,14 +158,15 @@
             * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/Node.java)
             * queues
               * [CircularQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java)
-              * [Deques](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/Deques.java)
+              * [Deque](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/Deque.java)
               * [GenericArrayListQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java)
               * [LinkedQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java)
               * [PriorityQueues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java)
-              * [Queues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/Queues.java)
+              * [Queue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/Queue.java)
             * stacks
               * [NodeStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java)
               * [ReverseStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java)
+              * [Stack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/Stack.java)
               * [StackArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java)
               * [StackArrayList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java)
               * [StackOfLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java)
@@ -193,6 +197,7 @@
               * [RedBlackBST](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java)
               * [SameTreesCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java)
               * [SegmentTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java)
+              * [SplayTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SplayTree.java)
               * [TreeRandomNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java)
               * [TrieImp](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java)
               * [VerticalOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java)
@@ -226,7 +231,6 @@
             * [EditDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java)
             * [EggDropping](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java)
             * [Fibonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java)
-            * [FordFulkerson](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java)
             * [KadaneAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java)
             * [Knapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java)
             * [KnapsackMemoization](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java)
@@ -291,6 +295,7 @@
             * [DistanceFormula](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DistanceFormula.java)
             * [DudeneyNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DudeneyNumber.java)
             * [EulerMethod](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/EulerMethod.java)
+            * [EulersFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/EulersFunction.java)
             * [Factorial](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Factorial.java)
             * [FactorialRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FactorialRecursion.java)
             * [FastInverseSqrt](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java)
@@ -356,6 +361,7 @@
             * [ReverseNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ReverseNumber.java)
             * [RomanNumeralUtil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/RomanNumeralUtil.java)
             * [SecondMinMax](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SecondMinMax.java)
+            * [SieveOfEratosthenes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java)
             * [SimpsonIntegration](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java)
             * [SquareFreeInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareFreeInteger.java)
             * [SquareRootWithBabylonianMethod](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java)
@@ -411,15 +417,13 @@
             * [CRCAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CRCAlgorithm.java)
             * [Damm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Damm.java)
             * [Dijkstra](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Dijkstra.java)
-            * [EulersFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/EulersFunction.java)
             * [FibbonaciSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/FibbonaciSeries.java)
             * [FloydTriangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/FloydTriangle.java)
-            * [GuassLegendre](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/GuassLegendre.java)
+            * [GaussLegendre](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/GaussLegendre.java)
             * [HappyNumbersSeq](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java)
             * [Huffman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Huffman.java)
             * [Implementing auto completing features using trie](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java)
             * [InsertDeleteInArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java)
-            * [KMP](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/KMP.java)
             * [KochSnowflake](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/KochSnowflake.java)
             * [Krishnamurthy](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Krishnamurthy.java)
             * [LinearCongruentialGenerator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/LinearCongruentialGenerator.java)
@@ -435,12 +439,10 @@
             * [PerlinNoise](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PerlinNoise.java)
             * [PrintAMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java)
             * [QueueUsingTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java)
-            * [RabinKarp](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RabinKarp.java)
             * [RemoveDuplicateFromString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java)
             * [ReturnSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReturnSubsequence.java)
             * [ReverseStackUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
             * [RotateMatrixBy90Degrees](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java)
-            * [SieveOfEratosthenes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java)
             * [SkylineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SkylineProblem.java)
             * [StringMatchFiniteAutomata](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java)
             * [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Sudoku.java)
@@ -553,14 +555,16 @@
             * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/HammingDistance.java)
             * [HorspoolSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/HorspoolSearch.java)
             * [Isomorphic](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Isomorphic.java)
+            * [KMP](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/KMP.java)
             * [LetterCombinationsOfPhoneNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java)
-            * [LongestNonRepeativeSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestNonRepeativeSubstring.java)
+            * [LongestNonRepetitiveSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java)
             * [LongestPalindromicSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java)
             * [Lower](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Lower.java)
             * [MyAtoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/MyAtoi.java)
             * [Palindrome](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Palindrome.java)
             * [Pangram](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Pangram.java)
             * [PermuteString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/PermuteString.java)
+            * [RabinKarp](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/RabinKarp.java)
             * [ReverseString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseString.java)
             * [ReverseStringRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java)
             * [ReverseWordsInString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java)
@@ -582,6 +586,7 @@
             * [FloodFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/FloodFillTest.java)
             * [MazeRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java)
             * [MColoringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/MColoringTest.java)
+            * [NQueensTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/NQueensTest.java)
             * [ParenthesesGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/ParenthesesGeneratorTest.java)
             * [PermutationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PermutationTest.java)
             * [PowerSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PowerSumTest.java)
@@ -609,10 +614,14 @@
             * [SimpleSubCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/SimpleSubCipherTest.java)
             * [VigenereTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/VigenereTest.java)
           * conversions
+            * [AnyBaseToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java)
             * [BinaryToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java)
             * [BinaryToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java)
             * [BinaryToOctalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java)
-            * [DecimalToHexaDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToHexaDecimalTest.java)
+            * [DecimalToAnyBaseTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToAnyBaseTest.java)
+            * [DecimalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToBinaryTest.java)
+            * [DecimalToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToHexadecimalTest.java)
+            * [DecimalToOctalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToOctalTest.java)
             * [HexaDecimalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java)
             * [HexaDecimalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexaDecimalToDecimalTest.java)
             * [HexToOctTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexToOctTest.java)
@@ -621,7 +630,11 @@
             * [OctalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java)
             * [OctalToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
             * [RomanToIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java)
+            * [UnitConversionsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java)
+            * [UnitsConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java)
           * datastructures
+            * bag
+              * [BagTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java)
             * bloomfilter
               * [BloomFilterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java)
             * buffers
@@ -639,8 +652,12 @@
               * [TwoPSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java)
             * disjointsetunion
               * [DisjointSetUnionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java)
+            * dynamicarray
+              * [DynamicArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java)
             * graphs
               * [BoruvkaAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
+              * [DijkstraAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java)
+              * [FordFulkersonTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java)
               * [HamiltonianCycleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java)
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
               * [TarjansAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
@@ -649,6 +666,7 @@
               * hashing
                 * [GenericHashMapUsingArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java)
                 * [GenericHashMapUsingArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java)
+                * [HashMapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java)
                 * [LinearProbingHashMapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMapTest.java)
                 * [MajorityElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java)
                 * [MapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java)
@@ -657,14 +675,23 @@
               * [FibonacciHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
             * lists
+              * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
               * [QuickSortLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java)
               * [ReverseKGroupTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java)
               * [RotateSinglyLinkedListsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java)
               * [SinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java)
               * [SkipListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java)
             * queues
+              * [CircularQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java)
+              * [DequeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java)
+              * [GenericArrayListQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java)
               * [LinkedQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java)
               * [PriorityQueuesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java)
+              * [QueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java)
+            * stacks
+              * [LinkedListStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java)
+              * [StackArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java)
+              * [StackArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java)
             * trees
               * [BinaryTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java)
               * [BSTFromSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTFromSortedArrayTest.java)
@@ -682,6 +709,7 @@
               * [PostOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/PostOrderTraversalTest.java)
               * [PreOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/PreOrderTraversalTest.java)
               * [SameTreesCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SameTreesCheckTest.java)
+              * [SplayTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java)
               * [TreeTestUtils](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java)
               * [VerticalOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversalTest.java)
               * [ZigzagTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/ZigzagTraversalTest.java)
@@ -689,18 +717,27 @@
             * [BinaryExponentiationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java)
             * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
           * dynamicprogramming
+            * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
             * [CatalanNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java)
             * [ClimbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java)
+            * [EditDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java)
             * [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
             * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
             * [KnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
             * [LevenshteinDistanceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
+            * [LongestAlternatingSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java)
             * [LongestIncreasingSubsequenceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java)
+            * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java)
+            * [LongestValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java)
             * [MinimumPathSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java)
             * [MinimumSumPartitionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java)
             * [OptimalJobSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
+            * [PalindromicPartitioningTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioningTest.java)
             * [PartitionProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java)
+            * [RegexMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/RegexMatchingTest.java)
+            * [ShortestCommonSupersequenceLengthTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLengthTest.java)
             * [SubsetCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java)
+            * [SubsetSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java)
             * [SumOfSubsetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java)
             * [TribonacciTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java)
             * [UniquePathsTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java)
@@ -733,9 +770,11 @@
             * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
             * [CombinationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CombinationsTest.java)
             * [CrossCorrelationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java)
+            * [DeterminantOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DeterminantOfMatrixTest.java)
             * [DigitalRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DigitalRootTest.java)
             * [DistanceFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java)
             * [DudeneyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java)
+            * [EulersFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/EulersFunctionTest.java)
             * [FactorialRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java)
             * [FactorialTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialTest.java)
             * [FastInverseSqrtTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java)
@@ -744,6 +783,7 @@
             * [FibonacciLoopTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciLoopTest.java)
             * [FibonacciNumberCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciNumberCheckTest.java)
             * [FibonacciNumberGoldenRationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciNumberGoldenRationTest.java)
+            * [FindKthNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java)
             * [FindMaxRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java)
             * [FindMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMaxTest.java)
             * [FindMinRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMinRecursionTest.java)
@@ -751,6 +791,7 @@
             * [FloorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FloorTest.java)
             * [FrizzyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FrizzyNumberTest.java)
             * [GaussianTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GaussianTest.java)
+            * [GCDRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GCDRecursionTest.java)
             * [GCDTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GCDTest.java)
             * [GenericRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GenericRootTest.java)
             * [HarshadNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java)
@@ -771,6 +812,7 @@
             * [MinValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MinValueTest.java)
             * [MobiusFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java)
             * [ModeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ModeTest.java)
+            * [NonRepeatingElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NonRepeatingElementTest.java)
             * [NthUglyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java)
             * [NumberOfDigitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java)
             * [PalindromeNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java)
@@ -783,12 +825,14 @@
             * [PollardRhoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PollardRhoTest.java)
             * [PowerOfTwoOrNotTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java)
             * [PowerUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java)
+            * [PowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowTest.java)
             * [PrimeCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PrimeCheckTest.java)
             * [PrimeFactorizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java)
             * [PronicNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PronicNumberTest.java)
             * [PythagoreanTripleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java)
             * [ReverseNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ReverseNumberTest.java)
             * [SecondMinMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java)
+            * [SieveOfEratosthenesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java)
             * [SquareFreeIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java)
             * [SquareRootwithBabylonianMethodTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareRootwithBabylonianMethodTest.java)
             * [SquareRootWithNewtonRaphsonTestMethod](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonTestMethod.java)
@@ -823,8 +867,8 @@
             * [CountWordsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountWordsTest.java)
             * [CRC16Test](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CRC16Test.java)
             * [CRCAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java)
-            * [EulersFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/EulersFunctionTest.java)
             * [FirstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/FirstFitCPUTest.java)
+            * [FloydTriangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/FloydTriangleTest.java)
             * [KadaneAlogrithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java)
             * [LineSweepTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/LineSweepTest.java)
             * [LinkListSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/LinkListSortTest.java)
@@ -833,7 +877,10 @@
             * [NewManShanksPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java)
             * [NextFitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/NextFitTest.java)
             * [PasswordGenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/PasswordGenTest.java)
-            * [SieveOfEratosthenesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SieveOfEratosthenesTest.java)
+            * [QueueUsingTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java)
+            * [RemoveDuplicateFromStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java)
+            * [ReturnSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java)
+            * [ReverseStackUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
             * [StringMatchFiniteAutomataTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java)
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
@@ -885,6 +932,7 @@
             * [OddEvenSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/OddEvenSortTest.java)
             * [PancakeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java)
             * [PatienceSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PatienceSortTest.java)
+            * [PigeonholeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PigeonholeSortTest.java)
             * [QuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/QuickSortTest.java)
             * [RadixSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/RadixSortTest.java)
             * [SelectionSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java)
@@ -905,6 +953,14 @@
             * [WaveSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WaveSortTest.java)
             * [WiggleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java)
           * stacks
+            * [BalancedBracketsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/BalancedBracketsTest.java)
+            * [DecimalToAnyUsingStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/DecimalToAnyUsingStackTest.java)
+            * [DuplicateBracketsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java)
+            * [InfixToPostfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java)
+            * [LargestRectangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java)
+            * [NextGreaterElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java)
+            * [NextSmallerElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
+            * [PostfixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java)
             * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
           * strings
             * [AhoCorasickTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
@@ -917,11 +973,13 @@
             * [HorspoolSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java)
             * [IsomorphicTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/IsomorphicTest.java)
             * [LetterCombinationsOfPhoneNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java)
-            * [LongestNonRepeativeSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestNonRepeativeSubstringTest.java)
+            * [LongestNonRepetitiveSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java)
+            * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java)
             * [LowerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LowerTest.java)
             * [MyAtoiTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/MyAtoiTest.java)
             * [PalindromeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PalindromeTest.java)
             * [PangramTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PangramTest.java)
+            * [PermuteStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PermuteStringTest.java)
             * [ReverseStringRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java)
             * [ReverseStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseStringTest.java)
             * [ReverseWordsInStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/SplayTree.java b/src/main/java/com/thealgorithms/datastructures/trees/SplayTree.java
new file mode 100644
index 000000000000..2668b609aedc
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/trees/SplayTree.java
@@ -0,0 +1,324 @@
+package com.thealgorithms.datastructures.trees;
+
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * Implementation of a Splay Tree data structure.
+ *
+ * A splay tree is a self-adjusting binary search tree with the additional
+ * property
+ * that recently accessed elements are quick to access again. It performs basic
+ * operations such as insertion, deletion, and searching in O(log n) amortized
+ * time,
+ * where n is the number of elements in the tree.
+ *
+ * The key feature of splay trees is the splay operation, which moves a node
+ * closer
+ * to the root of the tree when it is accessed. This operation helps to maintain
+ * good balance and improves the overall performance of the tree. After
+ * performing
+ * a splay operation, the accessed node becomes the new root of the tree.
+ *
+ * Splay trees have applications in various areas, including caching, network
+ * routing,
+ * and dynamic optimality analysis.
+ */
+public class SplayTree {
+    public static final TreeTraversal PRE_ORDER = new PreOrderTraversal();
+    public static final TreeTraversal IN_ORDER = new InOrderTraversal();
+    public static final TreeTraversal POST_ORDER = new PostOrderTraversal();
+
+    private Node root;
+
+    /**
+     * Checks if the tree is empty.
+     *
+     * @return True if the tree is empty, otherwise false.
+     */
+    public boolean isEmpty() {
+        return root == null;
+    }
+
+    /**
+     * Insert a key into the SplayTree.
+     *
+     * @param key The key to insert.
+     */
+    public void insert(final int key) {
+        root = insertRec(root, key);
+        root = splay(root, key);
+    }
+
+    /**
+     * Search for a key in the SplayTree.
+     *
+     * @param key The key to search for.
+     * @return True if the key is found, otherwise false.
+     */
+    public boolean search(int key) {
+        root = splay(root, key);
+        return root != null && root.key == key;
+    }
+
+    /**
+     * Deletes a key from the SplayTree.
+     *
+     * @param key The key to delete.
+     * @throws IllegalArgumentException If the tree is empty.
+     */
+    public void delete(final int key) {
+        if (isEmpty()) {
+            throw new EmptyTreeException("Cannot delete from an empty tree");
+        }
+
+        root = splay(root, key);
+
+        if (root.key != key) {
+            return;
+        }
+
+        if (root.left == null) {
+            root = root.right;
+        } else {
+            Node temp = root;
+            root = splay(root.left, findMax(root.left).key);
+            root.right = temp.right;
+        }
+    }
+
+    /**
+     * Perform a traversal of the SplayTree.
+     *
+     * @param traversal The type of traversal method.
+     * @return A list containing the keys in the specified traversal order.
+     */
+    public List<Integer> traverse(TreeTraversal traversal) {
+        List<Integer> result = new LinkedList<>();
+        traversal.traverse(root, result);
+        return result;
+    }
+
+    /**
+     * Finds the node with the maximum key in a given subtree.
+     *
+     * <p>
+     * This method traverses the right children of the subtree until it finds the
+     * rightmost node, which contains the maximum key.
+     * </p>
+     *
+     * @param root The root node of the subtree.
+     * @return The node with the maximum key in the subtree.
+     */
+    private Node findMax(Node root) {
+        while (root.right != null) {
+            root = root.right;
+        }
+        return root;
+    }
+
+    /**
+     * Zig operation.
+     *
+     * <p>
+     * The zig operation is used to perform a single rotation on a node to move it
+     * closer to
+     * the root of the tree. It is typically applied when the node is a left child
+     * of its parent
+     * and needs to be rotated to the right.
+     * </p>
+     *
+     * @param x The node to perform the zig operation on.
+     * @return The new root node after the operation.
+     */
+    private Node rotateRight(Node x) {
+        Node y = x.left;
+        x.left = y.right;
+        y.right = x;
+        return y;
+    }
+
+    /**
+     * Zag operation.
+     *
+     * <p>
+     * The zag operation is used to perform a single rotation on a node to move it
+     * closer to
+     * the root of the tree. It is typically applied when the node is a right child
+     * of its parent
+     * and needs to be rotated to the left.
+     * </p>
+     *
+     * @param x The node to perform the zag operation on.
+     * @return The new root node after the operation.
+     */
+    private Node rotateLeft(Node x) {
+        Node y = x.right;
+        x.right = y.left;
+        y.left = x;
+        return y;
+    }
+
+    /**
+     * Splay operation.
+     *
+     * <p>
+     * The splay operation is the core operation of a splay tree. It moves a
+     * specified node
+     * closer to the root of the tree by performing a series of rotations. The goal
+     * of the splay
+     * operation is to improve the access time for frequently accessed nodes by
+     * bringing them
+     * closer to the root.
+     * </p>
+     *
+     * <p>
+     * The splay operation consists of three main cases:
+     * <ul>
+     * <li>Zig-Zig case: Perform two consecutive rotations.</li>
+     * <li>Zig-Zag case: Perform two consecutive rotations in opposite
+     * directions.</li>
+     * <li>Zag-Zag case: Perform two consecutive rotations.</li>
+     * </ul>
+     * </p>
+     *
+     * <p>
+     * After performing the splay operation, the accessed node becomes the new root
+     * of the tree.
+     * </p>
+     *
+     * @param root The root of the subtree to splay.
+     * @param key  The key to splay around.
+     * @return The new root of the splayed subtree.
+     */
+    private Node splay(Node root, final int key) {
+        if (root == null || root.key == key) {
+            return root;
+        }
+
+        if (root.key > key) {
+            if (root.left == null) {
+                return root;
+            }
+            // Zig-Zig case
+            if (root.left.key > key) {
+                root.left.left = splay(root.left.left, key);
+                root = rotateRight(root);
+            } else if (root.left.key < key) {
+                root.left.right = splay(root.left.right, key);
+                if (root.left.right != null) {
+                    root.left = rotateLeft(root.left);
+                }
+            }
+            return (root.left == null) ? root : rotateRight(root);
+        } else {
+            if (root.right == null) {
+                return root;
+            }
+            // Zag-Zag case
+            if (root.right.key > key) {
+                root.right.left = splay(root.right.left, key);
+                if (root.right.left != null) {
+                    root.right = rotateRight(root.right);
+                }
+            } else if (root.right.key < key) {
+                root.right.right = splay(root.right.right, key);
+                root = rotateLeft(root);
+            }
+            return (root.right == null) ? root : rotateLeft(root);
+        }
+    }
+
+    private Node insertRec(Node root, final int key) {
+        if (root == null) {
+            return new Node(key);
+        }
+
+        if (key < root.key) {
+            root.left = insertRec(root.left, key);
+        } else if (key > root.key) {
+            root.right = insertRec(root.right, key);
+        } else {
+            throw new DuplicateKeyException("Duplicate key: " + key);
+        }
+
+        return root;
+    }
+
+    public static class EmptyTreeException extends RuntimeException {
+        private static final long serialVersionUID = 1L;
+
+        public EmptyTreeException(String message) {
+            super(message);
+        }
+    }
+
+    public static class DuplicateKeyException extends RuntimeException {
+        private static final long serialVersionUID = 1L;
+
+        public DuplicateKeyException(String message) {
+            super(message);
+        }
+    }
+
+    private static class Node {
+        final int key;
+        Node left;
+        Node right;
+
+        Node(int key) {
+            this.key = key;
+            left = null;
+            right = null;
+        }
+    }
+
+    public interface TreeTraversal {
+        /**
+         * Recursive function for a specific order traversal.
+         *
+         * @param root   The root of the subtree to traverse.
+         * @param result The list to store the traversal result.
+         */
+        void traverse(Node root, List<Integer> result);
+    }
+
+    private static final class InOrderTraversal implements TreeTraversal {
+        private InOrderTraversal() {
+        }
+
+        public void traverse(Node root, List<Integer> result) {
+            if (root != null) {
+                traverse(root.left, result);
+                result.add(root.key);
+                traverse(root.right, result);
+            }
+        }
+    }
+
+    private static final class PreOrderTraversal implements TreeTraversal {
+        private PreOrderTraversal() {
+        }
+
+        public void traverse(Node root, List<Integer> result) {
+            if (root != null) {
+                result.add(root.key);
+                traverse(root.left, result);
+                traverse(root.right, result);
+            }
+        }
+    }
+
+    private static final class PostOrderTraversal implements TreeTraversal {
+        private PostOrderTraversal() {
+        }
+
+        public void traverse(Node root, List<Integer> result) {
+            if (root != null) {
+                traverse(root.left, result);
+                traverse(root.right, result);
+                result.add(root.key);
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java
new file mode 100644
index 000000000000..d520be94e7f3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java
@@ -0,0 +1,113 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class SplayTreeTest {
+
+    @ParameterizedTest
+    @MethodSource("traversalStrategies")
+    public void testTraversal(SplayTree.TreeTraversal traversal, List<Integer> expected) {
+        SplayTree tree = createComplexTree();
+        List<Integer> result = tree.traverse(traversal);
+        assertEquals(expected, result);
+    }
+
+    @ParameterizedTest
+    @MethodSource("valuesToTest")
+    public void testSearch(int value) {
+        SplayTree tree = createComplexTree();
+        assertTrue(tree.search(value));
+    }
+
+    @ParameterizedTest
+    @MethodSource("valuesToTest")
+    public void testDelete(int value) {
+        SplayTree tree = createComplexTree();
+        assertTrue(tree.search(value));
+        tree.delete(value);
+        assertFalse(tree.search(value));
+    }
+
+    @ParameterizedTest
+    @MethodSource("nonExistentValues")
+    public void testSearchNonExistent(int value) {
+        SplayTree tree = createComplexTree();
+        assertFalse(tree.search(value));
+    }
+
+    @ParameterizedTest
+    @MethodSource("nonExistentValues")
+    public void testDeleteNonExistent(int value) {
+        SplayTree tree = createComplexTree();
+        tree.delete(value);
+        assertFalse(tree.search(value));
+    }
+
+    @ParameterizedTest
+    @MethodSource("valuesToTest")
+    public void testDeleteThrowsExceptionForEmptyTree(int value) {
+        SplayTree tree = new SplayTree();
+        assertThrows(SplayTree.EmptyTreeException.class, () -> tree.delete(value));
+    }
+
+    @ParameterizedTest
+    @MethodSource("valuesToTest")
+    public void testInsertThrowsExceptionForDuplicateKeys(int value) {
+        SplayTree tree = createComplexTree();
+        assertThrows(SplayTree.DuplicateKeyException.class, () -> tree.insert(value));
+    }
+
+    @ParameterizedTest
+    @MethodSource("valuesToTest")
+    public void testSearchInEmptyTree(int value) {
+        SplayTree tree = new SplayTree();
+        assertFalse(tree.search(value));
+    }
+
+    private static Stream<Object[]> traversalStrategies() {
+        return Stream.of(new Object[] {SplayTree.IN_ORDER, Arrays.asList(5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90)}, new Object[] {SplayTree.PRE_ORDER, Arrays.asList(15, 5, 10, 80, 70, 45, 25, 20, 35, 30, 40, 55, 50, 65, 60, 75, 90, 85)},
+            new Object[] {SplayTree.POST_ORDER, Arrays.asList(10, 5, 20, 30, 40, 35, 25, 50, 60, 65, 55, 45, 75, 70, 85, 90, 80, 15)});
+    }
+
+    private static Stream<Integer> valuesToTest() {
+        return Stream.of(5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90);
+    }
+
+    private static Stream<Integer> nonExistentValues() {
+        return Stream.of(0, 100, 42, 58);
+    }
+
+    private SplayTree createComplexTree() {
+        SplayTree tree = new SplayTree();
+
+        tree.insert(50);
+        tree.insert(30);
+        tree.insert(40);
+        tree.insert(70);
+        tree.insert(60);
+        tree.insert(20);
+        tree.insert(80);
+        tree.insert(10);
+        tree.insert(25);
+        tree.insert(35);
+        tree.insert(45);
+        tree.insert(55);
+        tree.insert(65);
+        tree.insert(75);
+        tree.insert(85);
+        tree.insert(5);
+        tree.insert(90);
+        tree.insert(15);
+
+        return tree;
+    }
+}

From 175c84673ab58b47816d0e73d3ab2781879f533b Mon Sep 17 00:00:00 2001
From: "Wole Jr." <32499062+wolejri@users.noreply.github.com>
Date: Tue, 3 Sep 2024 11:11:30 -0400
Subject: [PATCH 0375/1338] Added an edge case for AbsoluteMax (#5441)

* Added an edge case to test

* Fixed linting on added test
---
 src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java b/src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java
index 85ffb91e27f4..70d2f64bc541 100644
--- a/src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java
+++ b/src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java
@@ -12,6 +12,7 @@ void testGetMaxValue() {
         assertEquals(16, AbsoluteMax.getMaxValue(-2, 0, 16));
         assertEquals(-22, AbsoluteMax.getMaxValue(-3, -10, -22));
         assertEquals(-888, AbsoluteMax.getMaxValue(-888));
+        assertEquals(-1, AbsoluteMax.getMaxValue(-1, -1, -1, -1, -1));
     }
 
     @Test

From e0a1164cf59107a485754e18bbd5edb26b478330 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 6 Sep 2024 00:35:47 +0200
Subject: [PATCH 0376/1338] Chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.8.6.2 to 4.8.6.3 (#5443)

Chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.8.6.2 to 4.8.6.3.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.8.6.2...spotbugs-maven-plugin-4.8.6.3)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 96fd6e124704..97715d8b5980 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.8.6.2</version>
+                <version>4.8.6.3</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From fa2231788fcfef1079c371f6e75f06f772930fc9 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 8 Sep 2024 22:25:13 +0200
Subject: [PATCH 0377/1338] fix: `FindKthNumberTest` (#5444)

refactor: fix FindKthNumberTest
---
 src/test/java/com/thealgorithms/maths/FindKthNumberTest.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java b/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java
index ddf62ff1e33a..21285a527c37 100644
--- a/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java
@@ -41,14 +41,14 @@ public void testFindKthMaxInvalidK() {
     @Test
     public void testFindKthMaxLargeArray() {
         int[] array = generateArray(1000);
-        int k = new Random().nextInt(array.length);
+        int k = new Random().nextInt(1, array.length);
         int result = FindKthNumber.findKthMax(array, k);
         Arrays.sort(array);
         assertEquals(array[array.length - k], result);
     }
 
     public static int[] generateArray(int capacity) {
-        int size = new Random().nextInt(capacity) + 1;
+        int size = new Random().nextInt(2, capacity);
         int[] array = new int[size];
 
         for (int i = 0; i < size; i++) {

From bded78f8884d9b365beafa6735e0fbfb94fd073d Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 9 Sep 2024 09:07:30 +0200
Subject: [PATCH 0378/1338] refactor: `BFPRT` (#5445)

refactor: adding javadocs and tests for BFPRT
---
 .../java/com/thealgorithms/others/BFPRT.java  | 122 +++++++++++-------
 .../com/thealgorithms/others/BFPRTTest.java   |  34 +++++
 2 files changed, 111 insertions(+), 45 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/BFPRTTest.java

diff --git a/src/main/java/com/thealgorithms/others/BFPRT.java b/src/main/java/com/thealgorithms/others/BFPRT.java
index 1a5b44180651..58c6d4e56830 100644
--- a/src/main/java/com/thealgorithms/others/BFPRT.java
+++ b/src/main/java/com/thealgorithms/others/BFPRT.java
@@ -1,14 +1,22 @@
 package com.thealgorithms.others;
 
-import java.util.Arrays;
-
 /**
- * BFPRT algorithm.
+ * The BFPRT (Median of Medians) algorithm implementation.
+ * It provides a way to find the k-th smallest element in an unsorted array
+ * with an optimal worst-case time complexity of O(n).
+ * This algorithm is used to find the k smallest numbers in an array.
  */
 public final class BFPRT {
     private BFPRT() {
     }
 
+    /**
+     * Returns the k smallest elements from the array using the BFPRT algorithm.
+     *
+     * @param arr the input array
+     * @param k the number of smallest elements to return
+     * @return an array containing the k smallest elements, or null if k is invalid
+     */
     public static int[] getMinKNumsByBFPRT(int[] arr, int k) {
         if (k < 1 || k > arr.length) {
             return null;
@@ -16,9 +24,9 @@ public static int[] getMinKNumsByBFPRT(int[] arr, int k) {
         int minKth = getMinKthByBFPRT(arr, k);
         int[] res = new int[k];
         int index = 0;
-        for (int i = 0; i < arr.length; i++) {
-            if (arr[i] < minKth) {
-                res[index++] = arr[i];
+        for (int value : arr) {
+            if (value < minKth) {
+                res[index++] = value;
             }
         }
         for (; index != res.length; index++) {
@@ -27,17 +35,39 @@ public static int[] getMinKNumsByBFPRT(int[] arr, int k) {
         return res;
     }
 
+    /**
+     * Returns the k-th smallest element from the array using the BFPRT algorithm.
+     *
+     * @param arr the input array
+     * @param k the rank of the smallest element to find
+     * @return the k-th smallest element
+     */
     public static int getMinKthByBFPRT(int[] arr, int k) {
         int[] copyArr = copyArray(arr);
         return bfprt(copyArr, 0, copyArr.length - 1, k - 1);
     }
 
+    /**
+     * Creates a copy of the input array.
+     *
+     * @param arr the input array
+     * @return a copy of the array
+     */
     public static int[] copyArray(int[] arr) {
         int[] copyArr = new int[arr.length];
         System.arraycopy(arr, 0, copyArr, 0, arr.length);
         return copyArr;
     }
 
+    /**
+     * BFPRT recursive method to find the k-th smallest element.
+     *
+     * @param arr the input array
+     * @param begin the starting index
+     * @param end the ending index
+     * @param i the index of the desired smallest element
+     * @return the k-th smallest element
+     */
     public static int bfprt(int[] arr, int begin, int end, int i) {
         if (begin == end) {
             return arr[begin];
@@ -54,12 +84,12 @@ public static int bfprt(int[] arr, int begin, int end, int i) {
     }
 
     /**
-     * wikipedia: https://en.wikipedia.org/wiki/Median_of_medians .
+     * Finds the median of medians as the pivot element.
      *
-     * @param arr an array.
-     * @param begin begin num.
-     * @param end end num.
-     * @return median of medians.
+     * @param arr the input array
+     * @param begin the starting index
+     * @param end the ending index
+     * @return the median of medians
      */
     public static int medianOfMedians(int[] arr, int begin, int end) {
         int num = end - begin + 1;
@@ -71,12 +101,15 @@ public static int medianOfMedians(int[] arr, int begin, int end) {
         return bfprt(mArr, 0, mArr.length - 1, mArr.length / 2);
     }
 
-    public static void swap(int[] arr, int i, int j) {
-        int swap = arr[i];
-        arr[i] = arr[j];
-        arr[j] = swap;
-    }
-
+    /**
+     * Partitions the array around a pivot.
+     *
+     * @param arr the input array
+     * @param begin the starting index
+     * @param end the ending index
+     * @param num the pivot element
+     * @return the range where the pivot is located
+     */
     public static int[] partition(int[] arr, int begin, int end, int num) {
         int small = begin - 1;
         int cur = begin;
@@ -90,12 +123,17 @@ public static int[] partition(int[] arr, int begin, int end, int num) {
                 cur++;
             }
         }
-        int[] pivotRange = new int[2];
-        pivotRange[0] = small + 1;
-        pivotRange[1] = big - 1;
-        return pivotRange;
+        return new int[] {small + 1, big - 1};
     }
 
+    /**
+     * Finds the median of the elements between the specified range.
+     *
+     * @param arr the input array
+     * @param begin the starting index
+     * @param end the ending index
+     * @return the median of the specified range
+     */
     public static int getMedian(int[] arr, int begin, int end) {
         insertionSort(arr, begin, end);
         int sum = begin + end;
@@ -103,6 +141,13 @@ public static int getMedian(int[] arr, int begin, int end) {
         return arr[mid];
     }
 
+    /**
+     * Sorts a portion of the array using insertion sort.
+     *
+     * @param arr the input array
+     * @param begin the starting index
+     * @param end the ending index
+     */
     public static void insertionSort(int[] arr, int begin, int end) {
         if (arr == null || arr.length < 2) {
             return;
@@ -118,29 +163,16 @@ public static void insertionSort(int[] arr, int begin, int end) {
         }
     }
 
-    public static void main(String[] args) {
-        int[] arr = {
-            11,
-            9,
-            1,
-            3,
-            9,
-            2,
-            2,
-            5,
-            6,
-            5,
-            3,
-            5,
-            9,
-            7,
-            2,
-            5,
-            5,
-            1,
-            9,
-        };
-        int[] minK = getMinKNumsByBFPRT(arr, 5);
-        System.out.println(Arrays.toString(minK));
+    /**
+     * Swaps two elements in an array.
+     *
+     * @param arr the input array
+     * @param i the index of the first element
+     * @param j the index of the second element
+     */
+    public static void swap(int[] arr, int i, int j) {
+        int temp = arr[i];
+        arr[i] = arr[j];
+        arr[j] = temp;
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/BFPRTTest.java b/src/test/java/com/thealgorithms/others/BFPRTTest.java
new file mode 100644
index 000000000000..bb7c8f074864
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/BFPRTTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class BFPRTTest {
+
+    @ParameterizedTest
+    @MethodSource("minKNumsTestData")
+    void testGetMinKNumsByBFPRT(int[] arr, int k, int[] expected) {
+        int[] result = BFPRT.getMinKNumsByBFPRT(arr, k);
+        assertArrayEquals(expected, result);
+    }
+
+    private static Stream<Arguments> minKNumsTestData() {
+        return Stream.of(Arguments.of(new int[] {11, 9, 1, 3, 9, 2, 2, 5, 6, 5, 3, 5, 9, 7, 2, 5, 5, 1, 9}, 5, new int[] {1, 1, 2, 2, 2}), Arguments.of(new int[] {3, 2, 1}, 2, new int[] {1, 2}), Arguments.of(new int[] {7, 5, 9, 1, 3, 8, 2, 4, 6}, 3, new int[] {1, 2, 3}));
+    }
+
+    @ParameterizedTest
+    @MethodSource("minKthTestData")
+    void testGetMinKthByBFPRT(int[] arr, int k, int expected) {
+        int result = BFPRT.getMinKthByBFPRT(arr, k);
+        assertEquals(expected, result);
+    }
+
+    private static Stream<Arguments> minKthTestData() {
+        return Stream.of(Arguments.of(new int[] {3, 2, 1}, 2, 2), Arguments.of(new int[] {7, 5, 9, 1, 3, 8, 2, 4, 6}, 3, 3), Arguments.of(new int[] {5, 8, 6, 3, 2, 7, 1, 4}, 4, 4));
+    }
+}

From 65e32641fc96012ae840ebc93eb2176589527783 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Mon, 9 Sep 2024 09:15:41 +0200
Subject: [PATCH 0379/1338] refactor: `InverseOfMatrix` (#5446)

refactor: InverseOfMatrix
---
 .../thealgorithms/misc/InverseOfMatrix.java   | 74 ++++++-------------
 .../misc/InverseOfMatrixTest.java             | 28 +++++++
 2 files changed, 52 insertions(+), 50 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/misc/InverseOfMatrixTest.java

diff --git a/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java b/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java
index 5543463e9749..706feab0c69d 100644
--- a/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java
+++ b/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java
@@ -1,57 +1,29 @@
 package com.thealgorithms.misc;
 
-import java.util.Scanner;
-
-/*
- * Wikipedia link : https://en.wikipedia.org/wiki/Invertible_matrix
- *
- * Here we use gauss elimination method to find the inverse of a given matrix.
- * To understand gauss elimination method to find inverse of a matrix:
- * https://www.sangakoo.com/en/unit/inverse-matrix-method-of-gaussian-elimination
- *
- * We can also find the inverse of a matrix
+/**
+ * This class provides methods to compute the inverse of a square matrix
+ * using Gaussian elimination. For more details, refer to:
+ * https://en.wikipedia.org/wiki/Invertible_matrix
  */
 public final class InverseOfMatrix {
     private InverseOfMatrix() {
     }
 
-    public static void main(String[] argv) {
-        Scanner input = new Scanner(System.in);
-        System.out.println("Enter the matrix size (Square matrix only): ");
-        int n = input.nextInt();
-        double[][] a = new double[n][n];
-        System.out.println("Enter the elements of matrix: ");
-        for (int i = 0; i < n; i++) {
-            for (int j = 0; j < n; j++) {
-                a[i][j] = input.nextDouble();
-            }
-        }
-
-        double[][] d = invert(a);
-        System.out.println();
-        System.out.println("The inverse is: ");
-        for (int i = 0; i < n; ++i) {
-            for (int j = 0; j < n; ++j) {
-                System.out.print(d[i][j] + "  ");
-            }
-            System.out.println();
-        }
-        input.close();
-    }
-
     public static double[][] invert(double[][] a) {
         int n = a.length;
         double[][] x = new double[n][n];
         double[][] b = new double[n][n];
         int[] index = new int[n];
+
+        // Initialize the identity matrix
         for (int i = 0; i < n; ++i) {
             b[i][i] = 1;
         }
 
-        // Transform the matrix into an upper triangle
+        // Perform Gaussian elimination
         gaussian(a, index);
 
-        // Update the matrix b[i][j] with the ratios stored
+        // Update matrix b with the ratios stored during elimination
         for (int i = 0; i < n - 1; ++i) {
             for (int j = i + 1; j < n; ++j) {
                 for (int k = 0; k < n; ++k) {
@@ -60,7 +32,7 @@ public static double[][] invert(double[][] a) {
             }
         }
 
-        // Perform backward substitutions
+        // Perform backward substitution to find the inverse
         for (int i = 0; i < n; ++i) {
             x[n - 1][i] = b[index[n - 1]][i] / a[index[n - 1]][n - 1];
             for (int j = n - 2; j >= 0; --j) {
@@ -73,19 +45,20 @@ public static double[][] invert(double[][] a) {
         }
         return x;
     }
-
-    // Method to carry out the partial-pivoting Gaussian
-    // elimination.  Here index[] stores pivoting order.
-    public static void gaussian(double[][] a, int[] index) {
+    /**
+     * Method to carry out the partial-pivoting Gaussian
+     * elimination.  Here index[] stores pivoting order.
+     **/
+    private static void gaussian(double[][] a, int[] index) {
         int n = index.length;
         double[] c = new double[n];
 
-        // Initialize the index
+        // Initialize the index array
         for (int i = 0; i < n; ++i) {
             index[i] = i;
         }
 
-        // Find the rescaling factors, one from each row
+        // Find the rescaling factors for each row
         for (int i = 0; i < n; ++i) {
             double c1 = 0;
             for (int j = 0; j < n; ++j) {
@@ -97,22 +70,23 @@ public static void gaussian(double[][] a, int[] index) {
             c[i] = c1;
         }
 
-        // Search the pivoting element from each column
-        int k = 0;
+        // Perform pivoting
         for (int j = 0; j < n - 1; ++j) {
             double pi1 = 0;
+            int k = j;
             for (int i = j; i < n; ++i) {
-                double pi0 = Math.abs(a[index[i]][j]);
-                pi0 /= c[index[i]];
+                double pi0 = Math.abs(a[index[i]][j]) / c[index[i]];
                 if (pi0 > pi1) {
                     pi1 = pi0;
                     k = i;
                 }
             }
-            // Interchange rows according to the pivoting order
-            int itmp = index[j];
+
+            // Swap rows
+            int temp = index[j];
             index[j] = index[k];
-            index[k] = itmp;
+            index[k] = temp;
+
             for (int i = j + 1; i < n; ++i) {
                 double pj = a[index[i]][j] / a[index[j]][j];
 
diff --git a/src/test/java/com/thealgorithms/misc/InverseOfMatrixTest.java b/src/test/java/com/thealgorithms/misc/InverseOfMatrixTest.java
new file mode 100644
index 000000000000..2f20de444315
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/InverseOfMatrixTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class InverseOfMatrixTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testInvert(double[][] matrix, double[][] expectedInverse) {
+        double[][] result = InverseOfMatrix.invert(matrix);
+        assertMatrixEquals(expectedInverse, result);
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new double[][] {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}, new double[][] {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}), Arguments.of(new double[][] {{4, 7}, {2, 6}}, new double[][] {{0.6, -0.7}, {-0.2, 0.4}}));
+    }
+
+    private void assertMatrixEquals(double[][] expected, double[][] actual) {
+        for (int i = 0; i < expected.length; i++) {
+            assertArrayEquals(expected[i], actual[i], 1.0E-10, "Row " + i + " is not equal");
+        }
+    }
+}

From 648572a8c53540d64de52a4692d7c13ff81a4cb9 Mon Sep 17 00:00:00 2001
From: doxxx <doxxx93@gmail.com>
Date: Wed, 11 Sep 2024 21:49:36 +0900
Subject: [PATCH 0380/1338] Refactor ProcessDetails and
 PreemptivePriorityScheduling (#5448)

* Refactor ProcessDetails and PreemptivePriorityScheduling for consistency

* fix formatting

* fix formatting

* Improve test readability and maintainability
---
 .../devutils/entities/ProcessDetails.java     | 12 +++++
 .../PreemptivePriorityScheduling.java         | 54 +++++++++----------
 .../PreemptivePrioritySchedulingTest.java     | 35 ++++++------
 3 files changed, 55 insertions(+), 46 deletions(-)

diff --git a/src/main/java/com/thealgorithms/devutils/entities/ProcessDetails.java b/src/main/java/com/thealgorithms/devutils/entities/ProcessDetails.java
index 388fb3fd9056..b8b863eda3fc 100644
--- a/src/main/java/com/thealgorithms/devutils/entities/ProcessDetails.java
+++ b/src/main/java/com/thealgorithms/devutils/entities/ProcessDetails.java
@@ -6,6 +6,14 @@ public class ProcessDetails {
     private int burstTime;
     private int waitingTime;
     private int turnAroundTime;
+    private int priority;
+
+    public ProcessDetails(final String processId, final int arrivalTime, final int burstTime, int priority) {
+        this.processId = processId;
+        this.arrivalTime = arrivalTime;
+        this.burstTime = burstTime;
+        this.priority = priority;
+    }
 
     public ProcessDetails(final String processId, final int arrivalTime, final int burstTime) {
         this.processId = processId;
@@ -33,6 +41,10 @@ public int getTurnAroundTimeTime() {
         return turnAroundTime;
     }
 
+    public int getPriority() {
+        return priority;
+    }
+
     public void setProcessId(final String processId) {
         this.processId = processId;
     }
diff --git a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
index 9bcd5df81056..27d85a94d6f5 100644
--- a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.scheduling;
 
+import com.thealgorithms.devutils.entities.ProcessDetails;
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
@@ -7,44 +8,35 @@
 
 /**
  * Preemptive Priority Scheduling Algorithm
+ *
  * @author [Bama Charan Chhandogi](https://www.github.com/BamaCharanChhandogi)
  */
+public class PreemptivePriorityScheduling {
+    protected final List<ProcessDetails> processes;
+    protected final List<String> ganttChart;
 
-class Process {
-    String name;
-    int arrivalTime;
-    int burstTime;
-    int priority;
-
-    Process(String name, int arrivalTime, int burstTime, int priority) {
-        this.name = name;
-        this.arrivalTime = arrivalTime;
-        this.burstTime = burstTime;
-        this.priority = priority;
+    public PreemptivePriorityScheduling(List<ProcessDetails> processes) {
+        this.processes = new ArrayList<>(processes);
+        this.ganttChart = new ArrayList<>();
     }
-}
 
-public final class PreemptivePriorityScheduling {
-    private PreemptivePriorityScheduling() {
-    }
-    public static List<String> preemptivePriorityScheduling(List<Process> processes) {
-        List<String> ganttChart = new ArrayList<>();
-        PriorityQueue<Process> readyQueue = new PriorityQueue<>(Comparator.comparingInt(p -> - p.priority));
+    public void scheduleProcesses() {
+        PriorityQueue<ProcessDetails> readyQueue = new PriorityQueue<>(Comparator.comparingInt(ProcessDetails::getPriority).reversed().thenComparingInt(ProcessDetails::getArrivalTime));
 
         int currentTime = 0;
+        List<ProcessDetails> arrivedProcesses = new ArrayList<>();
 
         while (!processes.isEmpty() || !readyQueue.isEmpty()) {
-            while (!processes.isEmpty() && processes.get(0).arrivalTime <= currentTime) {
-                readyQueue.add(processes.remove(0));
-            }
+            updateArrivedProcesses(currentTime, arrivedProcesses);
+            readyQueue.addAll(arrivedProcesses);
+            arrivedProcesses.clear();
 
             if (!readyQueue.isEmpty()) {
-                Process currentProcess = readyQueue.poll();
+                ProcessDetails currentProcess = readyQueue.poll();
+                ganttChart.add(currentProcess.getProcessId());
+                currentProcess.setBurstTime(currentProcess.getBurstTime() - 1);
 
-                ganttChart.add(currentProcess.name);
-                currentProcess.burstTime--;
-
-                if (currentProcess.burstTime > 0) {
+                if (currentProcess.getBurstTime() > 0) {
                     readyQueue.add(currentProcess);
                 }
             } else {
@@ -53,7 +45,15 @@ public static List<String> preemptivePriorityScheduling(List<Process> processes)
 
             currentTime++;
         }
+    }
 
-        return ganttChart;
+    private void updateArrivedProcesses(int currentTime, List<ProcessDetails> arrivedProcesses) {
+        processes.removeIf(process -> {
+            if (process.getArrivalTime() <= currentTime) {
+                arrivedProcesses.add(process);
+                return true;
+            }
+            return false;
+        });
     }
 }
diff --git a/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
index 1c8a25dfda49..d0005dda9097 100644
--- a/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
@@ -2,32 +2,29 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.util.ArrayList;
-import java.util.Arrays;
+import com.thealgorithms.devutils.entities.ProcessDetails;
 import java.util.List;
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 /**
  * Test Cases of Preemptive Priority Scheduling Algorithm
+ *
  * @author [Bama Charan Chhandogi](https://www.github.com/BamaCharanChhandogi)
  */
 class PreemptivePrioritySchedulingTest {
+    @ParameterizedTest
+    @MethodSource("provideProcessesAndExpectedSchedules")
+    void testPreemptivePriorityScheduling(List<ProcessDetails> processes, List<String> expectedSchedule) {
+        PreemptivePriorityScheduling scheduler = new PreemptivePriorityScheduling(processes);
+        scheduler.scheduleProcesses();
+        assertEquals(expectedSchedule, scheduler.ganttChart);
+    }
 
-    @Test
-    void testPreemptivePriorityScheduling() {
-        // Arrange
-        List<Process> processes = new ArrayList<>();
-        processes.add(new Process("P1", 0, 5, 10));
-        processes.add(new Process("P2", 1, 4, 20));
-        processes.add(new Process("P3", 2, 2, 30));
-        processes.add(new Process("P4", 4, 1, 40));
-
-        List<String> expectedGanttChart = Arrays.asList("P1", "P2", "P3", "P3", "P4", "P2", "P2", "P2", "P1", "P1", "P1", "P1");
-
-        // Act
-        List<String> actualGanttChart = PreemptivePriorityScheduling.preemptivePriorityScheduling(processes);
-
-        // Assert
-        assertEquals(expectedGanttChart, actualGanttChart);
+    static Stream<Arguments> provideProcessesAndExpectedSchedules() {
+        return Stream.of(Arguments.of(List.of(new ProcessDetails("P1", 0, 5, 2), new ProcessDetails("P2", 1, 4, 4), new ProcessDetails("P3", 2, 2, 6), new ProcessDetails("P4", 4, 1, 8)), List.of("P1", "P2", "P3", "P3", "P4", "P2", "P2", "P2", "P1", "P1", "P1", "P1")),
+            Arguments.of(List.of(new ProcessDetails("P1", 2, 5, 3), new ProcessDetails("P2", 5, 3, 5), new ProcessDetails("P3", 7, 1, 9)), List.of("Idle", "Idle", "P1", "P1", "P1", "P2", "P2", "P3", "P2", "P1", "P1")));
     }
 }

From 2f9f448a1fec51292bcb85264965968ed1b0f0ba Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 17 Sep 2024 00:20:29 +0200
Subject: [PATCH 0381/1338] Chore(deps): bump gitpod/workspace-java-21 from
 2024-07-14-17-19-51 to 2024-09-11-00-04-27 (#5452)

Chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2024-07-14-17-19-51 to 2024-09-11-00-04-27.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index e6d0001e5571..f426f0921028 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-07-14-17-19-51
+FROM gitpod/workspace-java-21:2024-09-11-00-04-27
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 7bde1523a51ca917268042fb13a2a2bc334420b0 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 18 Sep 2024 22:58:49 +0200
Subject: [PATCH 0382/1338] style: use `getOrDefault` in `MajorityElement`
 (#5454)

---
 .../hashmap/hashing/MajorityElement.java             | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
index 56d2b0ef930c..0321f23b2f65 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
@@ -18,17 +18,13 @@ This method returns the majority element(s) in the given array of integers.
    */
     public static List<Integer> majority(int[] nums) {
         HashMap<Integer, Integer> numToCount = new HashMap<>();
-        int n = nums.length;
-        for (int i = 0; i < n; i++) {
-            if (numToCount.containsKey(nums[i])) {
-                numToCount.put(nums[i], numToCount.get(nums[i]) + 1);
-            } else {
-                numToCount.put(nums[i], 1);
-            }
+        for (final var num : nums) {
+            final var curCount = numToCount.getOrDefault(num, 0);
+            numToCount.put(num, curCount + 1);
         }
         List<Integer> majorityElements = new ArrayList<>();
         for (final var entry : numToCount.entrySet()) {
-            if (entry.getValue() >= n / 2) {
+            if (entry.getValue() >= nums.length / 2) {
                 majorityElements.add(entry.getKey());
             }
         }

From e782c7ac3dec130775e302fec26f5ff308fa63cf Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 19 Sep 2024 17:49:28 +0200
Subject: [PATCH 0383/1338] style: use `getOrDefault` in `MajorityElement`
 (#5455)

---
 .../datastructures/hashmap/hashing/MajorityElement.java        | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
index 0321f23b2f65..5424e14c72fd 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
@@ -19,8 +19,7 @@ This method returns the majority element(s) in the given array of integers.
     public static List<Integer> majority(int[] nums) {
         HashMap<Integer, Integer> numToCount = new HashMap<>();
         for (final var num : nums) {
-            final var curCount = numToCount.getOrDefault(num, 0);
-            numToCount.put(num, curCount + 1);
+            numToCount.merge(num, 1, Integer::sum);
         }
         List<Integer> majorityElements = new ArrayList<>();
         for (final var entry : numToCount.entrySet()) {

From 63fa04288b6cd72017389e0dc87a30dd8c689e16 Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sat, 21 Sep 2024 10:50:19 +0200
Subject: [PATCH 0384/1338] refactor: `ColorContrastRatio` (#5457)

---
 .../misc/ColorContrastRatio.java              | 54 ++-----------------
 .../misc/ColorContrastRatioTest.java          | 33 ++++++++++++
 2 files changed, 38 insertions(+), 49 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java

diff --git a/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java b/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java
index 2d8371a9a53d..a7e3f651cc85 100644
--- a/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java
+++ b/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java
@@ -7,8 +7,7 @@
  * calculate contrast ratio between colors on the web. This is used to calculate
  * the readability of a foreground color on top of a background color.
  * @since 2020-10-15
- * @see [Color Contrast
- * Ratio](https://www.w3.org/TR/WCAG20-TECHS/G17.html#G17-procedure)
+ * @see <a href="https://www.w3.org/TR/WCAG20-TECHS/G17.html#G17-procedure">Color Contrast Ratio</a>
  * @author [Seth Falco](https://github.com/SethFalco)
  */
 public class ColorContrastRatio {
@@ -34,8 +33,7 @@ public double getContrastRatio(Color a, Color b) {
      * @brief Calculates the relative luminance of a given color.
      * @param color Any color, used to get the red, green, and blue values.
      * @return The relative luminance of the color.
-     * @see [More info on relative
-     * luminance.](https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef)
+     * @see <a href="https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef">More info on relative luminance.</a>
      */
     public double getRelativeLuminance(Color color) {
         final double red = getColor(color.getRed());
@@ -46,11 +44,9 @@ public double getRelativeLuminance(Color color) {
     }
 
     /**
-     * @brief Calculates the final value for a color to be used in the relative
-     * luminance formula as described in step 1.
+     * @brief Calculates the final value for a color to be used in the relative luminance formula as described in step 1.
      * @param color8Bit 8-bit representation of a color component value.
-     * @return Value for the provided color component to be used in the relative
-     * luminance formula.
+     * @return Value for the provided color component to be used in the relative luminance formula.
      */
     public double getColor(int color8Bit) {
         final double sRgb = getColorSRgb(color8Bit);
@@ -58,51 +54,11 @@ public double getColor(int color8Bit) {
     }
 
     /**
-     * @brief Calculates the Color sRGB value as denoted in step 1 of the
-     * procedure document.
+     * @brief Calculates the Color sRGB value as denoted in step 1 of the procedure document.
      * @param color8Bit 8-bit representation of a color component value.
      * @return A percentile value of the color component.
      */
     private double getColorSRgb(double color8Bit) {
         return color8Bit / 255.0;
     }
-
-    /**
-     * You can check this example against another open-source implementation
-     * available on GitHub.
-     *
-     * @see [Online Contrast
-     * Ratio](https://contrast-ratio.com/#rgb%28226%2C%20229%2C%20248-on-rgb%2823%2C%20103%2C%20154%29)
-     * @see [GitHub Repository for Online Contrast
-     * Ratio](https://github.com/LeaVerou/contrast-ratio)
-     */
-    private static void test() {
-        final ColorContrastRatio algImpl = new ColorContrastRatio();
-
-        final Color black = Color.BLACK;
-        final double blackLuminance = algImpl.getRelativeLuminance(black);
-        assert blackLuminance == 0 : "Test 1 Failed - Incorrect relative luminance.";
-
-        final Color white = Color.WHITE;
-        final double whiteLuminance = algImpl.getRelativeLuminance(white);
-        assert whiteLuminance == 1 : "Test 2 Failed - Incorrect relative luminance.";
-
-        final double highestColorRatio = algImpl.getContrastRatio(black, white);
-        assert highestColorRatio == 21 : "Test 3 Failed - Incorrect contrast ratio.";
-
-        final Color foreground = new Color(23, 103, 154);
-        final double foregroundLuminance = algImpl.getRelativeLuminance(foreground);
-        assert foregroundLuminance == 0.12215748057375966 : "Test 4 Failed - Incorrect relative luminance.";
-
-        final Color background = new Color(226, 229, 248);
-        final double backgroundLuminance = algImpl.getRelativeLuminance(background);
-        assert backgroundLuminance == 0.7898468477881603 : "Test 5 Failed - Incorrect relative luminance.";
-
-        final double contrastRatio = algImpl.getContrastRatio(foreground, background);
-        assert contrastRatio == 4.878363954846178 : "Test 6 Failed - Incorrect contrast ratio.";
-    }
-
-    public static void main(String[] args) {
-        test();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java b/src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java
new file mode 100644
index 000000000000..6b80edf4b14c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.awt.Color;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class ColorContrastRatioTest {
+    private final ColorContrastRatio colorContrastRationCalculator = new ColorContrastRatio();
+
+    static Stream<Arguments> relativeLuminanceProvider() {
+        return Stream.of(Arguments.of(Color.BLACK, 0.0), Arguments.of(Color.WHITE, 1.0), Arguments.of(new Color(23, 103, 154), 0.12215748057375966), Arguments.of(new Color(226, 229, 248), 0.7898468477881603));
+    }
+
+    static Stream<Arguments> contrastRatioProvider() {
+        return Stream.of(Arguments.of(Color.BLACK, Color.WHITE, 21.0), Arguments.of(new Color(23, 103, 154), new Color(226, 229, 248), 4.878363954846178));
+    }
+
+    @ParameterizedTest
+    @MethodSource("relativeLuminanceProvider")
+    void testGetRelativeLuminance(Color color, double expectedLuminance) {
+        assertEquals(expectedLuminance, colorContrastRationCalculator.getRelativeLuminance(color), 1e-10);
+    }
+
+    @ParameterizedTest
+    @MethodSource("contrastRatioProvider")
+    void testGetContrastRatio(Color a, Color b, double expectedRatio) {
+        assertEquals(expectedRatio, colorContrastRationCalculator.getContrastRatio(a, b), 1e-10);
+    }
+}

From 0f0f5e172f068d99ea5c0b65cec7819aa2586ea9 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 21 Sep 2024 22:24:47 +0200
Subject: [PATCH 0385/1338] chore: add `run_infer.yml` (#5456)

* chore: add `run_infer.yml`

* chore: add infer output to `.gitignore`
---
 .github/workflows/run_infer.yml | 60 +++++++++++++++++++++++++++++++++
 .gitignore                      |  2 ++
 .inferconfig                    | 27 +++++++++++++++
 3 files changed, 89 insertions(+)
 create mode 100644 .github/workflows/run_infer.yml
 create mode 100644 .inferconfig

diff --git a/.github/workflows/run_infer.yml b/.github/workflows/run_infer.yml
new file mode 100644
index 000000000000..f587a1b6e2e4
--- /dev/null
+++ b/.github/workflows/run_infer.yml
@@ -0,0 +1,60 @@
+---
+name: run_infer
+
+'on':
+  workflow_dispatch:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  run_infer:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK
+        uses: actions/setup-java@v4
+        with:
+          java-version: 21
+          distribution: 'adopt'
+
+      - name: Set up OCaml
+        uses: ocaml/setup-ocaml@v3
+        with:
+          ocaml-compiler: 5
+
+      - name: Get current year/weak
+        run: echo "year_week=$(date +'%Y_%U')" >> $GITHUB_ENV
+
+      - name: Cache infer build
+        id: cache-infer
+        uses: actions/cache@v4
+        with:
+          path: infer
+          key: ${{ runner.os }}-infer-${{ env.year_week }}
+
+      - name: Build infer
+        if: steps.cache-infer.outputs.cache-hit != 'true'
+        run: |
+          cd ..
+          git clone https://github.com/facebook/infer.git
+          cd infer
+          ./build-infer.sh java
+          cp -r infer ../Java
+
+      - name: Add infer to PATH
+        run: |
+          echo "infer/bin" >> $GITHUB_PATH
+
+      - name: Display infer version
+        run: |
+          which infer
+          infer --version
+
+      - name: Run infer
+        run: |
+          mvn clean
+          infer --fail-on-issue  --print-logs --no-progress-bar -- mvn test
+...
diff --git a/.gitignore b/.gitignore
index bd1d54c0900a..eb9d33c78a33 100644
--- a/.gitignore
+++ b/.gitignore
@@ -42,3 +42,5 @@ local.properties
 gradle.properties
 .vscode
 *.log
+
+/infer-out/
diff --git a/.inferconfig b/.inferconfig
new file mode 100644
index 000000000000..96c34a54a0d8
--- /dev/null
+++ b/.inferconfig
@@ -0,0 +1,27 @@
+{
+    "report-block-list-path-regex": [
+        "src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java",
+        "src/main/java/com/thealgorithms/conversions/RomanToInteger.java",
+        "src/main/java/com/thealgorithms/conversions/UnitsConverter.java",
+        "src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java",
+        "src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java",
+        "src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java",
+        "src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java",
+        "src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java",
+        "src/main/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorder.java",
+        "src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java",
+        "src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java",
+        "src/main/java/com/thealgorithms/maths/NthUglyNumber.java",
+        "src/main/java/com/thealgorithms/maths/SimpsonIntegration.java",
+        "src/main/java/com/thealgorithms/others/Dijkstra.java",
+        "src/main/java/com/thealgorithms/sorts/TopologicalSort.java",
+        "src/main/java/com/thealgorithms/strings/AhoCorasick.java",
+        "src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java",
+        "src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java",
+        "src/test/java/com/thealgorithms/datastructures/trees/KDTreeTest.java",
+        "src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java",
+        "src/test/java/com/thealgorithms/searches/QuickSelectTest.java",
+        "src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java",
+        "src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java"
+    ]
+}

From 3fe1de00923ea8cf309eafb84009547440d92d40 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 21 Sep 2024 22:51:36 +0200
Subject: [PATCH 0386/1338] style: use consistent workflow naming (#5459)

---
 .github/workflows/{run_infer.yml => infer.yml} | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 rename .github/workflows/{run_infer.yml => infer.yml} (98%)

diff --git a/.github/workflows/run_infer.yml b/.github/workflows/infer.yml
similarity index 98%
rename from .github/workflows/run_infer.yml
rename to .github/workflows/infer.yml
index f587a1b6e2e4..121a6c728fbb 100644
--- a/.github/workflows/run_infer.yml
+++ b/.github/workflows/infer.yml
@@ -1,5 +1,5 @@
 ---
-name: run_infer
+name: Infer
 
 'on':
   workflow_dispatch:

From b849cbb60210b43c18195cc713bed8b44cc8610c Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 22 Sep 2024 11:20:23 +0200
Subject: [PATCH 0387/1338] fix: handle Null Dereference in `UnitsConverter`
 (#5460)

---
 .inferconfig                                             | 1 -
 .../com/thealgorithms/conversions/UnitsConverter.java    | 3 ++-
 .../thealgorithms/conversions/UnitsConverterTest.java    | 9 +++++++++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/.inferconfig b/.inferconfig
index 96c34a54a0d8..93bd1c355493 100644
--- a/.inferconfig
+++ b/.inferconfig
@@ -2,7 +2,6 @@
     "report-block-list-path-regex": [
         "src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java",
         "src/main/java/com/thealgorithms/conversions/RomanToInteger.java",
-        "src/main/java/com/thealgorithms/conversions/UnitsConverter.java",
         "src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java",
         "src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java",
         "src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java",
diff --git a/src/main/java/com/thealgorithms/conversions/UnitsConverter.java b/src/main/java/com/thealgorithms/conversions/UnitsConverter.java
index a19d40285047..81c4d4562070 100644
--- a/src/main/java/com/thealgorithms/conversions/UnitsConverter.java
+++ b/src/main/java/com/thealgorithms/conversions/UnitsConverter.java
@@ -3,6 +3,7 @@
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
+import java.util.NoSuchElementException;
 import java.util.Set;
 import org.apache.commons.lang3.tuple.Pair;
 
@@ -77,7 +78,7 @@ public double convert(final String inputUnit, final String outputUnit, final dou
             throw new IllegalArgumentException("inputUnit must be different from outputUnit.");
         }
         final var conversionKey = Pair.of(inputUnit, outputUnit);
-        return conversions.get(conversionKey).convert(value);
+        return conversions.computeIfAbsent(conversionKey, k -> { throw new NoSuchElementException("No converter for: " + k); }).convert(value);
     }
 
     public Set<String> availableUnits() {
diff --git a/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java b/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java
index 76e48f144fd6..580a66bc01ec 100644
--- a/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java
+++ b/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java
@@ -4,6 +4,7 @@
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.Map;
+import java.util.NoSuchElementException;
 import org.apache.commons.lang3.tuple.Pair;
 import org.junit.jupiter.api.Test;
 
@@ -15,4 +16,12 @@ void testConvertThrowsForSameUnits() {
         assertThrows(IllegalArgumentException.class, () -> someConverter.convert("A", "A", 20.0));
         assertThrows(IllegalArgumentException.class, () -> someConverter.convert("B", "B", 20.0));
     }
+
+    @Test
+    void testConvertThrowsForUnknownUnits() {
+        final UnitsConverter someConverter = new UnitsConverter(Map.ofEntries(entry(Pair.of("A", "B"), new AffineConverter(10.0, -20.0))));
+        assertThrows(NoSuchElementException.class, () -> someConverter.convert("A", "X", 20.0));
+        assertThrows(NoSuchElementException.class, () -> someConverter.convert("X", "A", 20.0));
+        assertThrows(NoSuchElementException.class, () -> someConverter.convert("X", "Y", 20.0));
+    }
 }

From 18f6f8c30ae993406cfac4774817b0313956161f Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 23 Sep 2024 10:33:55 +0200
Subject: [PATCH 0388/1338] fix: handle Null Dereference in `RomanToInteger`
 (#5461)

---
 .inferconfig                                        |  1 -
 .../thealgorithms/conversions/RomanToInteger.java   | 13 ++++++-------
 .../conversions/RomanToIntegerTest.java             |  9 +++++++++
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/.inferconfig b/.inferconfig
index 93bd1c355493..e7af307a63bf 100644
--- a/.inferconfig
+++ b/.inferconfig
@@ -1,7 +1,6 @@
 {
     "report-block-list-path-regex": [
         "src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java",
-        "src/main/java/com/thealgorithms/conversions/RomanToInteger.java",
         "src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java",
         "src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java",
         "src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java",
diff --git a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
index cf2d4145858f..1934e9b264c9 100644
--- a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
+++ b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
@@ -19,6 +19,10 @@ private RomanToInteger() {
         }
     };
 
+    private static int romanSymbolToInt(final char symbol) {
+        return ROMAN_TO_INT.computeIfAbsent(symbol, c -> { throw new IllegalArgumentException("Unknown Roman symbol: " + c); });
+    }
+
     // Roman Number = Roman Numerals
 
     /**
@@ -39,10 +43,10 @@ public static int romanToInt(String a) {
 
             if (prev != ' ') {
                 // checking current Number greater than previous or not
-                newPrev = ROMAN_TO_INT.get(prev) > newPrev ? ROMAN_TO_INT.get(prev) : newPrev;
+                newPrev = romanSymbolToInt(prev) > newPrev ? romanSymbolToInt(prev) : newPrev;
             }
 
-            int currentNum = ROMAN_TO_INT.get(c);
+            int currentNum = romanSymbolToInt(c);
 
             // if current number greater than prev max previous then add
             if (currentNum >= newPrev) {
@@ -57,9 +61,4 @@ public static int romanToInt(String a) {
 
         return sum;
     }
-
-    public static void main(String[] args) {
-        int sum = romanToInt("MDCCCIV");
-        System.out.println(sum);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java b/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java
index c51986f2a8d9..f03563971cb7 100644
--- a/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java
+++ b/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.conversions;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
@@ -10,5 +11,13 @@ public class RomanToIntegerTest {
     public void testRomanToInteger() {
         assertEquals(1994, RomanToInteger.romanToInt("MCMXCIV"));
         assertEquals(58, RomanToInteger.romanToInt("LVIII"));
+        assertEquals(1804, RomanToInteger.romanToInt("MDCCCIV"));
+    }
+
+    @Test
+    void testRomanToIntegerThrows() {
+        assertThrows(IllegalArgumentException.class, () -> RomanToInteger.romanToInt("Z"));
+        assertThrows(IllegalArgumentException.class, () -> RomanToInteger.romanToInt("MZI"));
+        assertThrows(IllegalArgumentException.class, () -> RomanToInteger.romanToInt("MMMO"));
     }
 }

From 2643ab5fe89a70e97f17789fe1b9380b86e351f8 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 23 Sep 2024 23:49:05 +0200
Subject: [PATCH 0389/1338] Chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.8.6.3 to 4.8.6.4 (#5465)

Chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.8.6.3 to 4.8.6.4.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.8.6.3...spotbugs-maven-plugin-4.8.6.4)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 97715d8b5980..7b072048ec03 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.8.6.3</version>
+                <version>4.8.6.4</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 1460eb7bbef3d8920dcaf47efdbe40a15a730f61 Mon Sep 17 00:00:00 2001
From: donutz03 <109514731+donutz03@users.noreply.github.com>
Date: Tue, 24 Sep 2024 16:21:57 +0300
Subject: [PATCH 0390/1338] =?UTF-8?q?Add=20Manacher=E2=80=99s=20Algorithm?=
 =?UTF-8?q?=20for=20Longest=20Palindromic=20Substring=20(#5462)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Added Manacher Algorithm

* Formatted ManacherTest.java

* Formatted Manacher.java

* Refactor: Update Manacher's algorithm tests and improve readability

- Added parameterized tests for longestPalindrome, empty cases, complex cases, and sentence palindromes.
- Removed unnecessary comments for cleaner code.
- Renamed variable `p` to `palindromeLengths` for clarity based on code review feedback.

---------

Co-authored-by: Ionut Hodoroaga <ionut.hodoroaga20@gmail.com>
---
 .../com/thealgorithms/strings/Manacher.java   | 69 +++++++++++++++++++
 .../thealgorithms/strings/ManacherTest.java   | 53 ++++++++++++++
 2 files changed, 122 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/Manacher.java
 create mode 100644 src/test/java/com/thealgorithms/strings/ManacherTest.java

diff --git a/src/main/java/com/thealgorithms/strings/Manacher.java b/src/main/java/com/thealgorithms/strings/Manacher.java
new file mode 100644
index 000000000000..34c303822bee
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/Manacher.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.strings;
+
+/**
+ * Wikipedia: https://en.wikipedia.org/wiki/Longest_palindromic_substring#Manacher's_algorithm
+ */
+public final class Manacher {
+
+    private Manacher() {
+    }
+
+    /**
+     * Finds the longest palindromic substring using Manacher's Algorithm
+     *
+     * @param s The input string
+     * @return The longest palindromic substring in {@code s}
+     */
+    public static String longestPalindrome(String s) {
+        final String processedString = preprocess(s);
+        int[] palindromeLengths = new int[processedString.length()];
+        int center = 0;
+        int rightBoundary = 0;
+        int maxLen = 0;
+        int centerIndex = 0;
+
+        for (int i = 1; i < processedString.length() - 1; i++) {
+            int mirror = 2 * center - i;
+
+            if (i < rightBoundary) {
+                palindromeLengths[i] = Math.min(rightBoundary - i, palindromeLengths[mirror]);
+            }
+
+            while (processedString.charAt(i + 1 + palindromeLengths[i]) == processedString.charAt(i - 1 - palindromeLengths[i])) {
+                palindromeLengths[i]++;
+            }
+
+            if (i + palindromeLengths[i] > rightBoundary) {
+                center = i;
+                rightBoundary = i + palindromeLengths[i];
+            }
+
+            if (palindromeLengths[i] > maxLen) {
+                maxLen = palindromeLengths[i];
+                centerIndex = i;
+            }
+        }
+
+        final int start = (centerIndex - maxLen) / 2;
+        return s.substring(start, start + maxLen);
+    }
+
+    /**
+     * Preprocesses the input string by inserting a special character ('#') between each character
+     * and adding '^' at the start and '$' at the end to avoid boundary conditions.
+     *
+     * @param s The original string
+     * @return The preprocessed string with additional characters
+     */
+    private static String preprocess(String s) {
+        if (s.isEmpty()) {
+            return "^$";
+        }
+        StringBuilder sb = new StringBuilder("^");
+        for (char c : s.toCharArray()) {
+            sb.append('#').append(c);
+        }
+        sb.append("#$");
+        return sb.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/ManacherTest.java b/src/test/java/com/thealgorithms/strings/ManacherTest.java
new file mode 100644
index 000000000000..dc74df31b866
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/ManacherTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class ManacherTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCasesForLongestPalindrome")
+    public void testLongestPalindrome(String input, String expected) {
+        assertEquals(expected, Manacher.longestPalindrome(input));
+    }
+
+    private static Stream<Arguments> provideTestCasesForLongestPalindrome() {
+        return Stream.of(Arguments.of("abracadabraabcdefggfedcbaabracadabra", "aabcdefggfedcbaa"), Arguments.of("somelongtextwithracecarmiddletext", "racecar"), Arguments.of("bananananananana", "ananananananana"), Arguments.of("qwertydefgfedzxcvbnm", "defgfed"),
+            Arguments.of("abcdefghijklmnopqrstuvwxyzzyxwvutsrqponmlkjihgfedcba", "abcdefghijklmnopqrstuvwxyzzyxwvutsrqponmlkjihgfedcba"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCasesForEmptyAndSingle")
+    public void testEmptyAndSingle(String input, String expected) {
+        assertEquals(expected, Manacher.longestPalindrome(input));
+    }
+
+    private static Stream<Arguments> provideTestCasesForEmptyAndSingle() {
+        return Stream.of(Arguments.of("", ""), Arguments.of("a", "a"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCasesForComplexCases")
+    public void testComplexCases(String input, String expected) {
+        assertEquals(expected, Manacher.longestPalindrome(input));
+    }
+
+    private static Stream<Arguments> provideTestCasesForComplexCases() {
+        return Stream.of(Arguments.of("abcdefghijklmnopqrstuvwxyzttattarrattatabcdefghijklmnopqrstuvwxyz", "tattarrattat"), Arguments.of("aaaaabaaaaacbaaaaa", "aaaaabaaaaa"), Arguments.of("sometextrandomabcdefgabcdefghhgfedcbahijklmnopqrstuvwxyz", "abcdefghhgfedcba"),
+            Arguments.of("therewasasignthatsaidmadaminedenimadamitwasthereallalong", "madaminedenimadam"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCasesForSentencePalindromes")
+    public void testSentencePalindromes(String input, String expected) {
+        assertEquals(expected, Manacher.longestPalindrome(input));
+    }
+
+    private static Stream<Arguments> provideTestCasesForSentencePalindromes() {
+        return Stream.of(Arguments.of("XThisisalongtextbuthiddeninsideisAmanaplanacanalPanamaWhichweknowisfamous", "lanacanal"), Arguments.of("AverylongstringthatcontainsNeveroddoreveninahiddenmanner", "everoddoreve"));
+    }
+}

From 27343e7aa874343cf084f767b1aaa71e9134bc5e Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 24 Sep 2024 20:00:38 +0200
Subject: [PATCH 0391/1338] fix: handle Null Dereference in `NthUglyNumber`
 (#5469)

---
 .inferconfig                                  |  1 -
 .../thealgorithms/maths/NthUglyNumber.java    | 22 +++++++++----------
 2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/.inferconfig b/.inferconfig
index e7af307a63bf..6af4f9e2e818 100644
--- a/.inferconfig
+++ b/.inferconfig
@@ -9,7 +9,6 @@
         "src/main/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorder.java",
         "src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java",
         "src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java",
-        "src/main/java/com/thealgorithms/maths/NthUglyNumber.java",
         "src/main/java/com/thealgorithms/maths/SimpsonIntegration.java",
         "src/main/java/com/thealgorithms/others/Dijkstra.java",
         "src/main/java/com/thealgorithms/sorts/TopologicalSort.java",
diff --git a/src/main/java/com/thealgorithms/maths/NthUglyNumber.java b/src/main/java/com/thealgorithms/maths/NthUglyNumber.java
index 103ff504ad14..90507701332f 100644
--- a/src/main/java/com/thealgorithms/maths/NthUglyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/NthUglyNumber.java
@@ -2,7 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HashMap;
+import org.apache.commons.lang3.tuple.MutablePair;
 
 /**
  * @brief class computing the n-th ugly number (when they are sorted)
@@ -16,8 +16,7 @@
  */
 public class NthUglyNumber {
     private ArrayList<Long> uglyNumbers = new ArrayList<>(Arrays.asList(1L));
-    private final int[] baseNumbers;
-    private HashMap<Integer, Integer> positions = new HashMap<>();
+    private ArrayList<MutablePair<Integer, Integer>> positions = new ArrayList<>();
 
     /**
      * @brief initialized the object allowing to compute ugly numbers with given base
@@ -29,9 +28,8 @@ public class NthUglyNumber {
             throw new IllegalArgumentException("baseNumbers must be non-empty.");
         }
 
-        this.baseNumbers = baseNumbers;
         for (final var baseNumber : baseNumbers) {
-            this.positions.put(baseNumber, 0);
+            this.positions.add(MutablePair.of(baseNumber, 0));
         }
     }
 
@@ -59,21 +57,21 @@ private void addUglyNumber() {
 
     private void updatePositions() {
         final var lastUglyNumber = uglyNumbers.get(uglyNumbers.size() - 1);
-        for (final var baseNumber : baseNumbers) {
-            if (computeCandidate(baseNumber) == lastUglyNumber) {
-                positions.put(baseNumber, positions.get(baseNumber) + 1);
+        for (var entry : positions) {
+            if (computeCandidate(entry) == lastUglyNumber) {
+                entry.setValue(entry.getValue() + 1);
             }
         }
     }
 
-    private long computeCandidate(final int candidateBase) {
-        return candidateBase * uglyNumbers.get(positions.get(candidateBase));
+    private long computeCandidate(final MutablePair<Integer, Integer> entry) {
+        return entry.getKey() * uglyNumbers.get(entry.getValue());
     }
 
     private long computeMinimalCandidate() {
         long res = Long.MAX_VALUE;
-        for (final var baseNumber : baseNumbers) {
-            res = Math.min(res, computeCandidate(baseNumber));
+        for (final var entry : positions) {
+            res = Math.min(res, computeCandidate(entry));
         }
         return res;
     }

From a54c3d463dc66ecbe44700096aef543c2aaa3e2a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 26 Sep 2024 06:57:27 +0200
Subject: [PATCH 0392/1338] Chore(deps): bump org.junit:junit-bom from 5.11.0
 to 5.11.1 (#5475)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.11.0 to 5.11.1.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.0...r5.11.1)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 7b072048ec03..9a540f69e45b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.11.0</version>
+                <version>5.11.1</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From a3cb8ee24f51b83c614443075727f93f556aa248 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 26 Sep 2024 07:01:46 +0200
Subject: [PATCH 0393/1338] Chore(deps-dev): bump
 org.junit.jupiter:junit-jupiter-api from 5.11.0 to 5.11.1 (#5474)

Chore(deps-dev): bump org.junit.jupiter:junit-jupiter-api

Bumps [org.junit.jupiter:junit-jupiter-api](https://github.com/junit-team/junit5) from 5.11.0 to 5.11.1.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.0...r5.11.1)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter-api
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 9a540f69e45b..7c18776a9000 100644
--- a/pom.xml
+++ b/pom.xml
@@ -44,7 +44,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>5.11.0</version>
+            <version>5.11.1</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 1e8abf1ddf257e9b1396a1156333ef948917416c Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 26 Sep 2024 07:05:34 +0200
Subject: [PATCH 0394/1338] Chore(deps-dev): bump
 org.junit.jupiter:junit-jupiter from 5.11.0 to 5.11.1 (#5473)

Chore(deps-dev): bump org.junit.jupiter:junit-jupiter

Bumps [org.junit.jupiter:junit-jupiter](https://github.com/junit-team/junit5) from 5.11.0 to 5.11.1.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.0...r5.11.1)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 7c18776a9000..fa78dcf09533 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.11.0</version>
+            <version>5.11.1</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 7c56a734e96ce7c48a5535c3d088755bf49742d8 Mon Sep 17 00:00:00 2001
From: Ahmed Elazab <105994948+ahmedelazab1220@users.noreply.github.com>
Date: Mon, 30 Sep 2024 20:54:24 +0300
Subject: [PATCH 0395/1338] Add Volume "Algorithm Frustum Of Cone" Then Test
 It. (#5479)

* Add Function volumeFrustum To Calculate Frustum Of Cone Then Test It.

* Add Function volumeFrustumOfCone To Calculate Frustum Of Cone Then Test It.

* Update VolumeTest.java

* Update Volume.java
---
 src/main/java/com/thealgorithms/maths/Volume.java    | 12 ++++++++++++
 .../java/com/thealgorithms/maths/VolumeTest.java     |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/src/main/java/com/thealgorithms/maths/Volume.java b/src/main/java/com/thealgorithms/maths/Volume.java
index 4b73f849bb81..0f282b2abae2 100644
--- a/src/main/java/com/thealgorithms/maths/Volume.java
+++ b/src/main/java/com/thealgorithms/maths/Volume.java
@@ -90,4 +90,16 @@ public static double volumePrism(double baseArea, double height) {
     public static double volumePyramid(double baseArea, double height) {
         return (baseArea * height) / 3;
     }
+
+    /**
+     * Calculate the volume of a frustum of a cone.
+     *
+     * @param r1 radius of the top of the frustum
+     * @param r2 radius of the bottom of the frustum
+     * @param height height of the frustum
+     * @return volume of the frustum
+     */
+    public static double volumeFrustumOfCone(double r1, double r2, double height) {
+        return (Math.PI * height / 3) * (r1 * r1 + r2 * r2 + r1 * r2);
+    }
 }
diff --git a/src/test/java/com/thealgorithms/maths/VolumeTest.java b/src/test/java/com/thealgorithms/maths/VolumeTest.java
index 1bdb3ae80040..7cd0c6716147 100644
--- a/src/test/java/com/thealgorithms/maths/VolumeTest.java
+++ b/src/test/java/com/thealgorithms/maths/VolumeTest.java
@@ -32,5 +32,8 @@ public void volume() {
 
         /* test pyramid */
         assertTrue(Volume.volumePyramid(10, 3) == 10.0);
+
+        /* test frustum */
+        assertTrue(Volume.volumeFrustumOfCone(3, 5, 7) == 359.188760060433);
     }
 }

From 1cb874f76402655224216dd390599f6df0090281 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 1 Oct 2024 00:23:59 +0200
Subject: [PATCH 0396/1338] Chore(deps): bump com.puppycrawl.tools:checkstyle
 from 10.18.1 to 10.18.2 (#5487)

Chore(deps): bump com.puppycrawl.tools:checkstyle

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.18.1 to 10.18.2.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.18.1...checkstyle-10.18.2)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index fa78dcf09533..9775e407d351 100644
--- a/pom.xml
+++ b/pom.xml
@@ -118,7 +118,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.18.1</version>
+                    <version>10.18.2</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 7a5a9e3bda44bdab23c8ace87b4cb67c231a2ea3 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 1 Oct 2024 00:47:40 +0200
Subject: [PATCH 0397/1338] Chore(deps): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.6.4 to 7.6.5 (#5486)

* Chore(deps): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.6.4 to 7.6.5.
- [Commits](https://github.com/mebigfatguy/fb-contrib/compare/v7.6.4...v7.6.5)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

* fix: suppress `BAS_BLOATED_ASSIGNMENT_SCOPE`

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 pom.xml              | 2 +-
 spotbugs-exclude.xml | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 9775e407d351..882575fc654e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -133,7 +133,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.4</version>
+                            <version>7.6.5</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 38d65b7ff507..2e6bf688f06c 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -207,6 +207,9 @@
     <Match>
         <Bug pattern="SLS_SUSPICIOUS_LOOP_SEARCH" />
     </Match>
+    <Match>
+        <Bug pattern="BAS_BLOATED_ASSIGNMENT_SCOPE" />
+    </Match>
     <!-- find-sec-bugs -->
     <Match>
         <Bug pattern="PREDICTABLE_RANDOM" />

From 7f60d57504ab8456b72057735a0dc93595ad847f Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 1 Oct 2024 11:56:36 +0200
Subject: [PATCH 0398/1338] style: include `NAB_NEEDLESS_BOX_TO_UNBOX` (#5488)

---
 spotbugs-exclude.xml                                           | 3 ---
 .../java/com/thealgorithms/misc/MedianOfRunningArrayTest.java  | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 2e6bf688f06c..bfc7716730c3 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -165,9 +165,6 @@
     <Match>
         <Bug pattern="DSOC_DUBIOUS_SET_OF_COLLECTIONS" />
     </Match>
-    <Match>
-        <Bug pattern="NAB_NEEDLESS_BOX_TO_UNBOX" />
-    </Match>
     <Match>
         <Bug pattern="FPL_FLOATING_POINT_LOOPS" />
     </Match>
diff --git a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
index 6307b8e19b5d..e64ae1b741b6 100644
--- a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
+++ b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
@@ -196,6 +196,6 @@ public void testWithDoubleValues() {
         stream.insert(12345.67891);
         assertEquals(12345.67891, stream.median());
         stream.insert(23456789.98);
-        assertEquals(Double.valueOf(11734567.83), stream.median(), .01);
+        assertEquals(11734567.83, stream.median(), .01);
     }
 }

From 0bd86b3d7ed24029a799e7215893865b7eb42c35 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 2 Oct 2024 16:04:52 +0530
Subject: [PATCH 0399/1338] Improve comments in ActivitySelection.java (#5485)

---
 DIRECTORY.md                                  |  5 ++
 .../greedyalgorithms/ActivitySelection.java   | 56 ++++++++++++++-----
 2 files changed, 46 insertions(+), 15 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index bbcee88e52be..0e96e8fb22bf 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -560,6 +560,7 @@
             * [LongestNonRepetitiveSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java)
             * [LongestPalindromicSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java)
             * [Lower](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Lower.java)
+            * [Manacher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Manacher.java)
             * [MyAtoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/MyAtoi.java)
             * [Palindrome](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Palindrome.java)
             * [Pangram](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Pangram.java)
@@ -846,6 +847,8 @@
             * [TwinPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TwinPrimeTest.java)
             * [VolumeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/VolumeTest.java)
           * misc
+            * [ColorContrastRatioTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java)
+            * [InverseOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/InverseOfMatrixTest.java)
             * [MapReduceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MapReduceTest.java)
             * [MedianOfMatrixtest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java)
             * [MedianOfRunningArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java)
@@ -857,6 +860,7 @@
             * [ArrayRightRotation](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotation.java)
             * [ArrayRightRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java)
             * [BestFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BestFitCPUTest.java)
+            * [BFPRTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BFPRTTest.java)
             * [BoyerMooreTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BoyerMooreTest.java)
             * cn
               * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java)
@@ -976,6 +980,7 @@
             * [LongestNonRepetitiveSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java)
             * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java)
             * [LowerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LowerTest.java)
+            * [ManacherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ManacherTest.java)
             * [MyAtoiTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/MyAtoiTest.java)
             * [PalindromeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PalindromeTest.java)
             * [PangramTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PangramTest.java)
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java b/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
index 88fbc50129ca..54ba4eb650a8 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java
@@ -4,39 +4,65 @@
 import java.util.Arrays;
 import java.util.Comparator;
 
-// Problem Link:  https://en.wikipedia.org/wiki/Activity_selection_problem
+// Problem Link: https://en.wikipedia.org/wiki/Activity_selection_problem
 
 public final class ActivitySelection {
+
+    // Private constructor to prevent instantiation of the utility class
     private ActivitySelection() {
     }
-    // Function to perform activity selection
+
+    /**
+     * Function to perform activity selection using a greedy approach.
+     *
+     * The goal is to select the maximum number of activities that don't overlap
+     * with each other, based on their start and end times. Activities are chosen
+     * such that no two selected activities overlap.
+     *
+     * @param startTimes Array containing the start times of the activities.
+     * @param endTimes   Array containing the end times of the activities.
+     * @return A list of indices representing the selected activities that can be
+     *         performed without overlap.
+     */
     public static ArrayList<Integer> activitySelection(int[] startTimes, int[] endTimes) {
         int n = startTimes.length;
-        int[][] activities = new int[n][3];
 
-        // Create a 2D array to store activities and their start/end times.
-        // Each row: [activity index, start time, end time]
+        // Create a 2D array to store activity indices along with their start and end
+        // times.
+        // Each row represents an activity in the format: [activity index, start time,
+        // end time].
+        int[][] activities = new int[n][3];
 
+        // Populate the 2D array with the activity index, start time, and end time.
         for (int i = 0; i < n; i++) {
-            activities[i][0] = i; // Assign activity index
-            activities[i][1] = startTimes[i]; // Assign start time
-            activities[i][2] = endTimes[i]; // Assign end time
+            activities[i][0] = i; // Assign the activity index
+            activities[i][1] = startTimes[i]; // Assign the start time of the activity
+            activities[i][2] = endTimes[i]; // Assign the end time of the activity
         }
 
-        // Sort activities by their end times in ascending order.
+        // Sort activities based on their end times in ascending order.
+        // This ensures that we always try to finish earlier activities first.
         Arrays.sort(activities, Comparator.comparingDouble(activity -> activity[2]));
-        int lastEndTime;
+        int lastEndTime; // Variable to store the end time of the last selected activity
+        // List to store the indices of selected activities
         ArrayList<Integer> selectedActivities = new ArrayList<>();
-        selectedActivities.add(activities[0][0]);
-        lastEndTime = activities[0][2];
 
-        // Iterate through sorted activities to select compatible ones.
+        // Select the first activity (as it has the earliest end time after sorting)
+        selectedActivities.add(activities[0][0]); // Add the first activity index to the result
+        lastEndTime = activities[0][2]; // Keep track of the end time of the last selected activity
+
+        // Iterate over the sorted activities to select the maximum number of compatible
+        // activities.
         for (int i = 1; i < n; i++) {
+            // If the start time of the current activity is greater than or equal to the
+            // end time of the last selected activity, it means there's no overlap.
             if (activities[i][1] >= lastEndTime) {
-                selectedActivities.add(activities[i][0]);
-                lastEndTime = activities[i][2];
+                selectedActivities.add(activities[i][0]); // Select this activity
+                lastEndTime = activities[i][2]; // Update the end time of the last selected activity
             }
         }
+
+        // Return the list of selected activity indices.
         return selectedActivities;
     }
 }

From dab8ff3d1dec14778036a953b0fb08e0e1f474af Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 2 Oct 2024 19:16:34 +0530
Subject: [PATCH 0400/1338] Improve comments in Mcoloring.java (#5484)

---
 .../thealgorithms/backtracking/MColoring.java | 67 ++++++++++++-------
 .../backtracking/MColoringTest.java           |  9 +--
 2 files changed, 48 insertions(+), 28 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/MColoring.java b/src/main/java/com/thealgorithms/backtracking/MColoring.java
index f069e46cc627..d0188dfd13aa 100644
--- a/src/main/java/com/thealgorithms/backtracking/MColoring.java
+++ b/src/main/java/com/thealgorithms/backtracking/MColoring.java
@@ -7,64 +7,82 @@
 import java.util.Set;
 
 /**
+ * Node class represents a graph node. Each node is associated with a color
+ * (initially 1) and contains a set of edges representing its adjacent nodes.
+ *
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
 class Node {
-    int color = 1;
-    Set<Integer> edges = new HashSet<Integer>();
+    int color = 1; // Initial color for each node
+    Set<Integer> edges = new HashSet<Integer>(); // Set of edges representing adjacent nodes
 }
 
+/**
+ * MColoring class solves the M-Coloring problem where the goal is to determine
+ * if it's possible to color a graph using at most M colors such that no two
+ * adjacent nodes have the same color.
+ */
 public final class MColoring {
+
     private MColoring() {
-    }
-    static int possiblePaint(ArrayList<Node> nodes, int n, int m) {
+    } // Prevent instantiation of utility class
 
-        // Create a visited array of n nodes
+    /**
+     * Determines whether it is possible to color the graph using at most M colors.
+     *
+     * @param nodes List of nodes representing the graph.
+     * @param n     The total number of nodes in the graph.
+     * @param m     The maximum number of allowed colors.
+     * @return true if the graph can be colored using M colors, false otherwise.
+     */
+    static boolean isColoringPossible(ArrayList<Node> nodes, int n, int m) {
+
+        // Visited array keeps track of whether each node has been processed.
         ArrayList<Integer> visited = new ArrayList<Integer>();
         for (int i = 0; i < n + 1; i++) {
-            visited.add(0);
+            visited.add(0); // Initialize all nodes as unvisited (0)
         }
 
-        // maxColors used till now are 1 as
-        // all nodes are painted color 1
+        // The number of colors used so far (initially set to 1, since all nodes
+        // start with color 1).
         int maxColors = 1;
 
+        // Loop through all the nodes to ensure every node is visited, in case the
+        // graph is disconnected.
         for (int sv = 1; sv <= n; sv++) {
             if (visited.get(sv) > 0) {
-                continue;
+                continue; // Skip nodes that are already visited
             }
 
-            // If the starting point is unvisited,
-            // mark it visited and push it in queue
+            // If the node is unvisited, mark it as visited and add it to the queue for BFS.
             visited.set(sv, 1);
             Queue<Integer> q = new LinkedList<>();
             q.add(sv);
 
-            // BFS
+            // Perform BFS to process all nodes and their adjacent nodes
             while (q.size() != 0) {
-                int top = q.peek();
+                int top = q.peek(); // Get the current node from the queue
                 q.remove();
 
-                // Checking all adjacent nodes
-                // to "top" edge in our queue
+                // Check all adjacent nodes of the current node
                 for (int it : nodes.get(top).edges) {
 
-                    // If the color of the
-                    // adjacent node is same, increase it by
-                    // 1
+                    // If the adjacent node has the same color as the current node, increment its
+                    // color to avoid conflict.
                     if (nodes.get(top).color == nodes.get(it).color) {
                         nodes.get(it).color += 1;
                     }
 
-                    // If number of colors used exceeds m,
-                    // return 0
+                    // Keep track of the maximum number of colors used so far
                     maxColors = Math.max(maxColors, Math.max(nodes.get(top).color, nodes.get(it).color));
+
+                    // If the number of colors used exceeds the allowed limit M, return false.
                     if (maxColors > m) {
-                        return 0;
+                        return false;
                     }
 
-                    // If the adjacent node is not visited,
-                    // mark it visited and push it in queue
+                    // If the adjacent node hasn't been visited yet, mark it as visited and add it
+                    // to the queue for further processing.
                     if (visited.get(it) == 0) {
                         visited.set(it, 1);
                         q.add(it);
@@ -72,6 +90,7 @@ static int possiblePaint(ArrayList<Node> nodes, int n, int m) {
                 }
             }
         }
-        return 1;
+
+        return true; // Possible to color the entire graph with M or fewer colors.
     }
 }
diff --git a/src/test/java/com/thealgorithms/backtracking/MColoringTest.java b/src/test/java/com/thealgorithms/backtracking/MColoringTest.java
index 8b505abbc046..f3f25933b7a1 100644
--- a/src/test/java/com/thealgorithms/backtracking/MColoringTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/MColoringTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.backtracking;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.ArrayList;
 import org.junit.jupiter.api.Test;
@@ -16,7 +17,7 @@ void testGraphColoring1() {
         int[][] graph = {{0, 1, 1, 1}, {1, 0, 1, 0}, {1, 1, 0, 1}, {1, 0, 1, 0}};
         int m = 3; // Number of colors
 
-        assertEquals(1, MColoring.possiblePaint(createGraph(graph), n, m));
+        assertTrue(MColoring.isColoringPossible(createGraph(graph), n, m));
     }
 
     @Test
@@ -25,7 +26,7 @@ void testGraphColoring2() {
         int[][] graph = {{0, 1, 1, 1, 0}, {1, 0, 0, 1, 0}, {1, 0, 0, 1, 1}, {1, 1, 1, 0, 1}, {0, 0, 1, 1, 0}};
         int m = 2; // Number of colors
 
-        assertEquals(0, MColoring.possiblePaint(createGraph(graph), n, m));
+        assertFalse(MColoring.isColoringPossible(createGraph(graph), n, m));
     }
 
     @Test
@@ -34,7 +35,7 @@ void testGraphColoring3() {
         int[][] graph = {{0, 1, 1}, {1, 0, 1}, {1, 1, 0}};
         int m = 2; // Number of colors
 
-        assertEquals(0, MColoring.possiblePaint(createGraph(graph), n, m));
+        assertFalse(MColoring.isColoringPossible(createGraph(graph), n, m));
     }
 
     private ArrayList<Node> createGraph(int[][] graph) {

From e6f597acaf743515dd16ceb23aaa12fc44303a6f Mon Sep 17 00:00:00 2001
From: B Karthik <115967163+BKarthik7@users.noreply.github.com>
Date: Wed, 2 Oct 2024 19:20:30 +0530
Subject: [PATCH 0401/1338] Add Gale-Shapley Algorithm and Tests (#5494)

---
 DIRECTORY.md                                  |  2 +
 .../greedyalgorithms/GaleShapley.java         | 65 +++++++++++++++++
 .../greedyalgorithms/GaleShapleyTest.java     | 72 +++++++++++++++++++
 3 files changed, 139 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0e96e8fb22bf..ee09790ed64d 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -265,6 +265,7 @@
             * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
             * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java)
             * [FractionalKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
+            * [GaleShapley](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java)
             * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
             * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java)
           * io
@@ -749,6 +750,7 @@
             * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
             * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java)
             * [FractionalKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
+            * [GaleShapleyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java)
             * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
             * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java)
           * io
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java b/src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java
new file mode 100644
index 000000000000..a4a0366375eb
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java
@@ -0,0 +1,65 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.Map;
+
+/**
+ * Implementation of the Gale-Shapley Algorithm for Stable Matching.
+ * Problem link: https://en.wikipedia.org/wiki/Stable_marriage_problem
+ */
+public final class GaleShapley {
+
+    private GaleShapley() {
+    }
+
+    /**
+     * Function to find stable matches between men and women.
+     *
+     * @param womenPrefs A map containing women's preferences where each key is a woman and the value is an array of men in order of preference.
+     * @param menPrefs   A map containing men's preferences where each key is a man and the value is an array of women in order of preference.
+     * @return A map containing stable matches where the key is a woman and the value is her matched man.
+     */
+    public static Map<String, String> stableMatch(Map<String, LinkedList<String>> womenPrefs, Map<String, LinkedList<String>> menPrefs) {
+        // Initialize all men as free
+        Map<String, String> engagements = new HashMap<>();
+        LinkedList<String> freeMen = new LinkedList<>(menPrefs.keySet());
+
+        // While there are free men
+        while (!freeMen.isEmpty()) {
+            String man = freeMen.poll(); // Get the first free man
+            LinkedList<String> manPref = menPrefs.get(man); // Get the preferences of the man
+
+            // Check if manPref is null or empty
+            if (manPref == null || manPref.isEmpty()) {
+                continue; // Skip if no preferences
+            }
+
+            // Propose to the first woman in the man's preference list
+            String woman = manPref.poll();
+            String fiance = engagements.get(woman);
+
+            // If the woman is not engaged, engage her with the current man
+            if (fiance == null) {
+                engagements.put(woman, man);
+            } else {
+                // If the woman prefers the current man over her current fiance
+                LinkedList<String> womanPrefList = womenPrefs.get(woman);
+
+                // Check if womanPrefList is null
+                if (womanPrefList == null) {
+                    continue; // Skip if no preferences for the woman
+                }
+
+                if (womanPrefList.indexOf(man) < womanPrefList.indexOf(fiance)) {
+                    engagements.put(woman, man);
+                    freeMen.add(fiance); // Previous fiance becomes free
+                } else {
+                    // Woman rejects the new proposal, the man remains free
+                    freeMen.add(man);
+                }
+            }
+        }
+        return engagements; // Return the stable matches
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java
new file mode 100644
index 000000000000..fcd173202469
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java
@@ -0,0 +1,72 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import org.junit.jupiter.api.Test;
+
+public class GaleShapleyTest {
+
+    @Test
+    public void testStableMatch() {
+        Map<String, LinkedList<String>> womenPrefs = new HashMap<>();
+        womenPrefs.put("A", new LinkedList<>(List.of("X", "Y", "Z")));
+        womenPrefs.put("B", new LinkedList<>(List.of("Y", "X", "Z")));
+        womenPrefs.put("C", new LinkedList<>(List.of("X", "Y", "Z")));
+
+        Map<String, LinkedList<String>> menPrefs = new HashMap<>();
+        menPrefs.put("X", new LinkedList<>(List.of("A", "B", "C")));
+        menPrefs.put("Y", new LinkedList<>(List.of("B", "A", "C")));
+        menPrefs.put("Z", new LinkedList<>(List.of("A", "B", "C")));
+
+        Map<String, String> result = GaleShapley.stableMatch(womenPrefs, menPrefs);
+
+        Map<String, String> expected = new HashMap<>();
+        expected.put("A", "X");
+        expected.put("B", "Y");
+        expected.put("C", "Z");
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testSinglePair() {
+        Map<String, LinkedList<String>> womenPrefs = new HashMap<>();
+        womenPrefs.put("A", new LinkedList<>(List.of("X")));
+
+        Map<String, LinkedList<String>> menPrefs = new HashMap<>();
+        menPrefs.put("X", new LinkedList<>(List.of("A")));
+
+        Map<String, String> result = GaleShapley.stableMatch(womenPrefs, menPrefs);
+
+        Map<String, String> expected = new HashMap<>();
+        expected.put("A", "X");
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testEqualPreferences() {
+        Map<String, LinkedList<String>> womenPrefs = new HashMap<>();
+        womenPrefs.put("A", new LinkedList<>(List.of("X", "Y", "Z")));
+        womenPrefs.put("B", new LinkedList<>(List.of("X", "Y", "Z")));
+        womenPrefs.put("C", new LinkedList<>(List.of("X", "Y", "Z")));
+
+        Map<String, LinkedList<String>> menPrefs = new HashMap<>();
+        menPrefs.put("X", new LinkedList<>(List.of("A", "B", "C")));
+        menPrefs.put("Y", new LinkedList<>(List.of("A", "B", "C")));
+        menPrefs.put("Z", new LinkedList<>(List.of("A", "B", "C")));
+
+        Map<String, String> result = GaleShapley.stableMatch(womenPrefs, menPrefs);
+
+        Map<String, String> expected = new HashMap<>();
+        expected.put("A", "X");
+        expected.put("B", "Y");
+        expected.put("C", "Z");
+
+        assertEquals(expected, result);
+    }
+}

From 842ff5294f5e97dfd1e4c09f9d9e01a89ac16e32 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 2 Oct 2024 19:25:57 +0530
Subject: [PATCH 0402/1338] Improve comments & readability in
 ClimbingStairs.java (#5498)

---
 .../dynamicprogramming/ClimbingStairs.java    | 46 ++++++++++++++-----
 1 file changed, 35 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java b/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java
index d79ed3c23e13..0f0f5375ba82 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java
@@ -1,31 +1,55 @@
 package com.thealgorithms.dynamicprogramming;
 
-/* A DynamicProgramming solution for Climbing Stairs' problem Returns the
-    distinct ways can you climb to the staircase by either climbing 1 or 2 steps.
-
-    Link : https://medium.com/analytics-vidhya/leetcode-q70-climbing-stairs-easy-444a4aae54e8
-*/
+/*
+ * A dynamic programming solution for the "Climbing Stairs" problem.
+ * Returns the no. of distinct ways to climb to the top
+ * of a staircase when you can climb either 1 or 2 steps at a time.
+ *
+ * For example, if there are 5 steps, the possible ways to climb the
+ * staircase are:
+ * 1. 1-1-1-1-1
+ * 2. 1-1-1-2
+ * 3. 1-2-1-1
+ * 4. 2-1-1-1
+ * 5. 2-2-1
+ * 6. 1-1-2-1
+ * 7. 1-2-2
+ * 8. 2-1-2
+ * Ans: 8 ways
+ */
 public final class ClimbingStairs {
+
     private ClimbingStairs() {
     }
 
+    /**
+     * Calculates the no. of distinct ways to climb a staircase with n steps.
+     *
+     * @param n the no. of steps in the staircase (non-negative integer)
+     * @return the no. of distinct ways to climb to the top
+     *         - Returns 0 if n is 0 (no steps to climb).
+     *         - Returns 1 if n is 1 (only one way to climb).
+     *         - For n > 1, it returns the total no. of ways to climb.
+     */
     public static int numberOfWays(int n) {
 
+        // Base case: if there are no steps or only one step, return n.
         if (n == 1 || n == 0) {
             return n;
         }
-        int prev = 1;
-        int curr = 1;
 
-        int next;
+        int prev = 1; // Ways to reach the step before the current one (step 1)
+        int curr = 1; // Ways to reach the current step (step 2)
+        int next; // Total ways to reach the next step
 
-        for (int i = 2; i <= n; i++) {
+        for (int i = 2; i <= n; i++) { // step 2 to n
             next = curr + prev;
-            prev = curr;
 
+            // Move the pointers to the next step
+            prev = curr;
             curr = next;
         }
 
-        return curr;
+        return curr; // Ways to reach the nth step
     }
 }

From e493eb295852d68a4de47ab6301598ade66d3051 Mon Sep 17 00:00:00 2001
From: Tarun Vishwakarma <138651451+TarunVishwakarma1@users.noreply.github.com>
Date: Wed, 2 Oct 2024 23:34:01 +0530
Subject: [PATCH 0403/1338] Add Edmonds Blossom Algorithm (#5471)

---
 DIRECTORY.md                                  |   2 +
 .../graphs/EdmondsBlossomAlgorithm.java       | 251 ++++++++++++++++++
 .../graphs/EdmondsBlossomAlgorithmTest.java   | 119 +++++++++
 3 files changed, 372 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index ee09790ed64d..6f63a88b085a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -107,6 +107,7 @@
               * [ConnectedComponent](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java)
               * [Cycles](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java)
               * [DijkstraAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java)
+              * [EdmondsBlossomAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java)
               * [FloydWarshall](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java)
               * [FordFulkerson](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java)
               * [Graphs](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java)
@@ -659,6 +660,7 @@
             * graphs
               * [BoruvkaAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
               * [DijkstraAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java)
+              * [EdmondsBlossomAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java)
               * [FordFulkersonTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java)
               * [HamiltonianCycleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java)
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java
new file mode 100644
index 000000000000..27ad96d71876
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java
@@ -0,0 +1,251 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+/**
+ * The EdmondsBlossomAlgorithm class implements Edmonds' Blossom Algorithm
+ * to find the maximum matching in a general graph. The algorithm efficiently
+ * handles cases where the graph contains odd-length cycles by contracting
+ * "blossoms" and finding augmenting paths.
+ *<p>
+ * <a href="https://stanford.edu/~rezab/classes/cme323/S16/projects_reports/shoemaker_vare.pdf">Documentation of Algorithm (Stanford University)</a>
+ * <p></p>
+ * <a href="https://en.wikipedia.org/wiki/Blossom_algorithm">Wikipedia Documentation</a>
+ */
+public final class EdmondsBlossomAlgorithm {
+
+    private EdmondsBlossomAlgorithm() {
+    }
+
+    private static final int UNMATCHED = -1; // Constant to represent unmatched vertices
+
+    /**
+     * Finds the maximum matching in a general graph (Edmonds Blossom Algorithm).
+     *
+     * @param edges A list of edges in the graph.
+     * @param vertexCount The number of vertices in the graph.
+     * @return A list of matched pairs of vertices.
+     */
+    public static List<int[]> maximumMatching(List<int[]> edges, int vertexCount) {
+        List<List<Integer>> graph = new ArrayList<>(vertexCount);
+
+        // Initialize each vertex's adjacency list.
+        for (int i = 0; i < vertexCount; i++) {
+            graph.add(new ArrayList<>());
+        }
+
+        // Populate the graph with the edges
+        for (int[] edge : edges) {
+            int u = edge[0];
+            int v = edge[1];
+            graph.get(u).add(v);
+            graph.get(v).add(u);
+        }
+
+        // Initial matching array and auxiliary data structures
+        int[] match = new int[vertexCount];
+        Arrays.fill(match, UNMATCHED); // All vertices are initially unmatched
+        int[] parent = new int[vertexCount];
+        int[] base = new int[vertexCount];
+        boolean[] inBlossom = new boolean[vertexCount]; // Indicates if a vertex is part of a blossom
+        boolean[] inQueue = new boolean[vertexCount]; // Tracks vertices in the BFS queue
+
+        // Main logic for finding maximum matching
+        for (int u = 0; u < vertexCount; u++) {
+            if (match[u] == UNMATCHED) {
+                // BFS initialization
+                Arrays.fill(parent, UNMATCHED);
+                for (int i = 0; i < vertexCount; i++) {
+                    base[i] = i; // Each vertex is its own base initially
+                }
+                Arrays.fill(inBlossom, false);
+                Arrays.fill(inQueue, false);
+
+                Queue<Integer> queue = new LinkedList<>();
+                queue.add(u);
+                inQueue[u] = true;
+
+                boolean augmentingPathFound = false;
+
+                // BFS to find augmenting paths
+                while (!queue.isEmpty() && !augmentingPathFound) {
+                    int current = queue.poll(); // Use a different name for clarity
+                    for (int y : graph.get(current)) {
+                        // Skip if we are looking at the same edge as the current match
+                        if (match[current] == y) {
+                            continue;
+                        }
+
+                        if (base[current] == base[y]) {
+                            continue; // Avoid self-loops
+                        }
+
+                        if (parent[y] == UNMATCHED) {
+                            // Case 1: y is unmatched, we've found an augmenting path
+                            if (match[y] == UNMATCHED) {
+                                parent[y] = current;
+                                augmentingPathFound = true;
+                                updateMatching(match, parent, y); // Augment along this path
+                                break;
+                            }
+
+                            // Case 2: y is matched, add y's match to the queue
+                            int z = match[y];
+                            parent[y] = current;
+                            parent[z] = y;
+                            if (!inQueue[z]) {
+                                queue.add(z);
+                                inQueue[z] = true;
+                            }
+                        } else {
+                            // Case 3: Both x and y have a parent; check for a cycle/blossom
+                            int baseU = findBase(base, parent, current, y);
+                            if (baseU != UNMATCHED) {
+                                contractBlossom(new BlossomData(new BlossomAuxData(queue, parent, base, inBlossom, match, inQueue), current, y, baseU));
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        // Create result list of matched pairs
+        List<int[]> matchingResult = new ArrayList<>();
+        for (int v = 0; v < vertexCount; v++) {
+            if (match[v] != UNMATCHED && v < match[v]) {
+                matchingResult.add(new int[] {v, match[v]});
+            }
+        }
+
+        return matchingResult;
+    }
+
+    /**
+     * Updates the matching along the augmenting path found.
+     *
+     * @param match The matching array.
+     * @param parent The parent array used during the BFS.
+     * @param u The starting node of the augmenting path.
+     */
+    private static void updateMatching(int[] match, int[] parent, int u) {
+        while (u != UNMATCHED) {
+            int v = parent[u];
+            int next = match[v];
+            match[v] = u;
+            match[u] = v;
+            u = next;
+        }
+    }
+
+    /**
+     * Finds the base of a node in the blossom.
+     *
+     * @param base The base array.
+     * @param parent The parent array.
+     * @param u One end of the edge.
+     * @param v The other end of the edge.
+     * @return The base of the node or UNMATCHED.
+     */
+    private static int findBase(int[] base, int[] parent, int u, int v) {
+        boolean[] visited = new boolean[base.length];
+
+        // Mark ancestors of u
+        int currentU = u;
+        while (true) {
+            currentU = base[currentU]; // Move assignment out of the condition
+            visited[currentU] = true;
+            if (parent[currentU] == UNMATCHED) {
+                break;
+            }
+            currentU = parent[currentU]; // Move assignment out of the condition
+        }
+
+        // Find the common ancestor of v
+        int currentV = v;
+        while (true) {
+            currentV = base[currentV]; // Move assignment out of the condition
+            if (visited[currentV]) {
+                return currentV;
+            }
+            currentV = parent[currentV]; // Move assignment out of the condition
+        }
+    }
+
+    /**
+     * Contracts a blossom and updates the base array.
+     *
+     * @param blossomData The data containing the parameters related to the blossom contraction.
+     */
+    private static void contractBlossom(BlossomData blossomData) {
+        for (int x = blossomData.u; blossomData.auxData.base[x] != blossomData.lca; x = blossomData.auxData.parent[blossomData.auxData.match[x]]) {
+            int baseX = blossomData.auxData.base[x];
+            int matchBaseX = blossomData.auxData.base[blossomData.auxData.match[x]];
+
+            // Split the inner assignment into two separate assignments
+            blossomData.auxData.inBlossom[baseX] = true;
+            blossomData.auxData.inBlossom[matchBaseX] = true;
+        }
+
+        for (int x = blossomData.v; blossomData.auxData.base[x] != blossomData.lca; x = blossomData.auxData.parent[blossomData.auxData.match[x]]) {
+            int baseX = blossomData.auxData.base[x];
+            int matchBaseX = blossomData.auxData.base[blossomData.auxData.match[x]];
+
+            // Split the inner assignment into two separate assignments
+            blossomData.auxData.inBlossom[baseX] = true;
+            blossomData.auxData.inBlossom[matchBaseX] = true;
+        }
+
+        // Update the base for all marked vertices
+        for (int i = 0; i < blossomData.auxData.base.length; i++) {
+            if (blossomData.auxData.inBlossom[blossomData.auxData.base[i]]) {
+                blossomData.auxData.base[i] = blossomData.lca; // Contract to the lowest common ancestor
+                if (!blossomData.auxData.inQueue[i]) {
+                    blossomData.auxData.queue.add(i); // Add to queue if not already present
+                    blossomData.auxData.inQueue[i] = true;
+                }
+            }
+        }
+    }
+
+    /**
+     * Auxiliary data class to encapsulate common parameters for the blossom operations.
+     */
+    static class BlossomAuxData {
+        Queue<Integer> queue; // Queue for BFS traversal
+        int[] parent; // Parent array to store the paths
+        int[] base; // Base array to track the base of each vertex
+        boolean[] inBlossom; // Flags to indicate if a vertex is in a blossom
+        int[] match; // Array to store matches for each vertex
+        boolean[] inQueue; // Flags to track vertices in the BFS queue
+
+        BlossomAuxData(Queue<Integer> queue, int[] parent, int[] base, boolean[] inBlossom, int[] match, boolean[] inQueue) {
+            this.queue = queue;
+            this.parent = parent;
+            this.base = base;
+            this.inBlossom = inBlossom;
+            this.match = match;
+            this.inQueue = inQueue;
+        }
+    }
+
+    /**
+     * BlossomData class with reduced parameters.
+     */
+    static class BlossomData {
+        BlossomAuxData auxData; // Use the auxiliary data class
+        int u; // One vertex in the edge
+        int v; // Another vertex in the edge
+        int lca; // Lowest Common Ancestor
+
+        BlossomData(BlossomAuxData auxData, int u, int v, int lca) {
+            this.auxData = auxData;
+            this.u = u;
+            this.v = v;
+            this.lca = lca;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java
new file mode 100644
index 000000000000..4a7232447e50
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java
@@ -0,0 +1,119 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the EdmondsBlossomAlgorithm class.
+ *
+ * These tests ensure that the Edmonds' Blossom Algorithm implementation
+ * works as expected for various graph structures, returning the correct
+ * maximum matching.
+ */
+public class EdmondsBlossomAlgorithmTest {
+
+    /**
+     * Helper method to convert a list of matching pairs into a sorted 2D array.
+     * Sorting ensures consistent ordering of pairs and vertices for easier comparison in tests.
+     *
+     * @param matching List of matched pairs returned by the algorithm.
+     * @return A sorted 2D array of matching pairs.
+     */
+    private int[][] convertMatchingToArray(List<int[]> matching) {
+        // Convert the list of pairs into an array
+        int[][] result = matching.toArray(new int[0][]);
+
+        // Sort each individual pair for consistency
+        for (int[] pair : result) {
+            Arrays.sort(pair);
+        }
+
+        // Sort the array of pairs to ensure consistent order
+        Arrays.sort(result, (a, b) -> Integer.compare(a[0], b[0]));
+        return result;
+    }
+
+    /**
+     * Test Case 1: A triangle graph where vertices 0, 1, and 2 form a cycle.
+     * The expected maximum matching is a single pair (0, 1) or any equivalent pair from the cycle.
+     */
+    @Test
+    public void testCase1() {
+        List<int[]> edges = Arrays.asList(new int[] {0, 1}, new int[] {1, 2}, new int[] {2, 0});
+        List<int[]> matching = EdmondsBlossomAlgorithm.maximumMatching(edges, 3);
+
+        int[][] expected = new int[][] {{0, 1}};
+        assertArrayEquals(expected, convertMatchingToArray(matching));
+    }
+
+    /**
+     * Test Case 2: A disconnected graph where vertices 0, 1, 2 form one component,
+     * and vertices 3, 4 form another. The expected maximum matching is two pairs:
+     * (0, 1) and (3, 4).
+     */
+    @Test
+    public void testCase2() {
+        List<int[]> edges = Arrays.asList(new int[] {0, 1}, new int[] {1, 2}, new int[] {3, 4});
+        List<int[]> matching = EdmondsBlossomAlgorithm.maximumMatching(edges, 5);
+
+        int[][] expected = new int[][] {{0, 1}, {3, 4}};
+        assertArrayEquals(expected, convertMatchingToArray(matching));
+    }
+
+    /**
+     * Test Case 3: A cycle graph involving vertices 0, 1, 2, 3 forming a cycle,
+     * with an additional edge (4, 5) outside the cycle.
+     * The expected maximum matching is (0, 1) and (4, 5).
+     */
+    @Test
+    public void testCase3() {
+        List<int[]> edges = Arrays.asList(new int[] {0, 1}, new int[] {1, 2}, new int[] {2, 3}, new int[] {3, 0}, new int[] {4, 5});
+        List<int[]> matching = EdmondsBlossomAlgorithm.maximumMatching(edges, 6);
+
+        // Updated expected output to include the maximum matching pairs
+        int[][] expected = new int[][] {{0, 1}, {2, 3}, {4, 5}};
+        assertArrayEquals(expected, convertMatchingToArray(matching));
+    }
+
+    /**
+     * Test Case 4: A graph with no edges.
+     * Since there are no edges, the expected matching is an empty set.
+     */
+    @Test
+    public void testCaseNoMatching() {
+        List<int[]> edges = Collections.emptyList(); // No edges
+        List<int[]> matching = EdmondsBlossomAlgorithm.maximumMatching(edges, 3);
+
+        int[][] expected = new int[][] {}; // No pairs expected
+        assertArrayEquals(expected, convertMatchingToArray(matching));
+    }
+
+    /**
+     * Test Case 5: A more complex graph with multiple cycles and extra edges.
+     * This tests the algorithm's ability to handle larger, more intricate graphs.
+     * The expected matching is {{0, 1}, {2, 5}, {3, 4}}.
+     */
+    @Test
+    public void testCaseLargeGraph() {
+        List<int[]> edges = Arrays.asList(new int[] {0, 1}, new int[] {1, 2}, new int[] {2, 3}, new int[] {3, 4}, new int[] {4, 5}, new int[] {5, 0}, new int[] {1, 4}, new int[] {2, 5});
+        List<int[]> matching = EdmondsBlossomAlgorithm.maximumMatching(edges, 6);
+
+        // Check if the size of the matching is correct (i.e., 3 pairs)
+        assertEquals(3, matching.size());
+
+        // Check that the result contains valid pairs (any order is fine)
+        // Valid maximum matchings could be {{0, 1}, {2, 5}, {3, 4}} or {{0, 1}, {2, 3}, {4, 5}}, etc.
+        int[][] possibleMatching1 = new int[][] {{0, 1}, {2, 5}, {3, 4}};
+        int[][] possibleMatching2 = new int[][] {{0, 1}, {2, 3}, {4, 5}};
+        int[][] result = convertMatchingToArray(matching);
+
+        // Assert that the result is one of the valid maximum matchings
+        assertTrue(Arrays.deepEquals(result, possibleMatching1) || Arrays.deepEquals(result, possibleMatching2));
+    }
+}

From 013d122e7dcb302bc47aca78f451f0ed043b6a45 Mon Sep 17 00:00:00 2001
From: Tuhinm2002 <75078694+Tuhinm2002@users.noreply.github.com>
Date: Thu, 3 Oct 2024 00:21:23 +0530
Subject: [PATCH 0404/1338] feat: add recursion subsets (#5503)

---
 .../Recursion/GenerateSubsets.java            | 36 +++++++++++++++++++
 .../Recursion/GenerateSubsetsTest.java        | 36 +++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java
 create mode 100644 src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java

diff --git a/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java b/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java
new file mode 100644
index 000000000000..417bf1307790
--- /dev/null
+++ b/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.Recursion;
+
+// program to find power set of a string
+
+import java.util.ArrayList;
+import java.util.List;
+
+public final class GenerateSubsets {
+
+    private GenerateSubsets() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    public static List<String> subsetRecursion(String str) {
+        return doRecursion("", str);
+    }
+
+    private static List<String> doRecursion(String p, String up) {
+        if (up.isEmpty()) {
+            List<String> list = new ArrayList<>();
+            list.add(p);
+            return list;
+        }
+
+        // Taking the character
+        char ch = up.charAt(0);
+        // Adding the character in the recursion
+        List<String> left = doRecursion(p + ch, up.substring(1));
+        // Not adding the character in the recursion
+        List<String> right = doRecursion(p, up.substring(1));
+
+        left.addAll(right);
+
+        return left;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java b/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java
new file mode 100644
index 000000000000..d4bc7e488f80
--- /dev/null
+++ b/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.Recursion;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public final class GenerateSubsetsTest {
+
+    @Test
+    void subsetRecursionTestOne() {
+        String str = "abc";
+        String[] expected = new String[] {"abc", "ab", "ac", "a", "bc", "b", "c", ""};
+
+        List<String> ans = GenerateSubsets.subsetRecursion(str);
+        assertArrayEquals(ans.toArray(), expected);
+    }
+
+    @Test
+    void subsetRecursionTestTwo() {
+        String str = "cbf";
+        String[] expected = new String[] {"cbf", "cb", "cf", "c", "bf", "b", "f", ""};
+
+        List<String> ans = GenerateSubsets.subsetRecursion(str);
+        assertArrayEquals(ans.toArray(), expected);
+    }
+
+    @Test
+    void subsetRecursionTestThree() {
+        String str = "aba";
+        String[] expected = new String[] {"aba", "ab", "aa", "a", "ba", "b", "a", ""};
+
+        List<String> ans = GenerateSubsets.subsetRecursion(str);
+        assertArrayEquals(ans.toArray(), expected);
+    }
+}

From d436910ac492213954af0a160dc6590cd8def216 Mon Sep 17 00:00:00 2001
From: Muhammad Junaid Khalid <mjk22071998@gmail.com>
Date: Thu, 3 Oct 2024 10:58:22 +0500
Subject: [PATCH 0405/1338] Sorted Linked List Added (#5519)

* Sorted Linked List added with Javadoc and tests

* "Added comments to SortedLinkedList.java to describe the implementation and provide a reference link."

* Upgraded test from junit 4 to junit 5

* Added space before braces of functions

* Rename SortedlinkedListTest.java to SortedLinkedListTest.java

* made to string null safe

* Updated tail

* "Added assignment of `this.tail` to `newNode` in `SortedLinkedList` class."

* Remove assertions for minValue and maxValue in empty list test

* tried to get link updated

* "Fixed whitespace and formatting issues in SortedLinkedList.java and SortedLinkedListTest.java"

* formatting of test file corrected

* Removed few whitespaces

* Addressed comments by alxkm

* "Updated toString method to include brackets and removed default Node constructor."

* tests updated
---
 .../lists/SortedLinkedList.java               | 141 ++++++++++++++++++
 .../lists/SortedLinkedListTest.java           |  67 +++++++++
 2 files changed, 208 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java
new file mode 100644
index 000000000000..4cf782679b7c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java
@@ -0,0 +1,141 @@
+package com.thealgorithms.datastructures.lists;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A SortedLinkedList is a data structure that maintains a sorted list of elements.
+ * Elements are ordered based on their natural ordering or by a Comparator provided at the time of creation.
+ * This implementation uses a singly linked list to store the elements.
+ * Further details can be found on this link
+ * https://runestone.academy/ns/books/published/cppds/LinearLinked/ImplementinganOrderedList.html
+ */
+public class SortedLinkedList {
+    private Node head;
+    private Node tail;
+
+    public SortedLinkedList() {
+        this.head = null;
+        this.tail = null;
+    }
+
+    /**
+     * Inserts a new element into the sorted linked list.
+     * @param value the value to be inserted
+     */
+    public void insert(int value) {
+        Node newNode = new Node(value);
+        if (head == null) {
+            this.head = newNode;
+            this.tail = newNode;
+        } else if (value < head.value) {
+            newNode.next = this.head;
+            this.head = newNode;
+        } else if (value > tail.value) {
+            this.tail.next = newNode;
+            this.tail = newNode;
+        } else {
+            Node temp = head;
+            while (temp.next != null && temp.next.value < value) {
+                temp = temp.next;
+            }
+            newNode.next = temp.next;
+            temp.next = newNode;
+            if (newNode.next == null) {
+                this.tail = newNode;
+            }
+        }
+    }
+
+    /**
+     * Displays the elements of the sorted linked list.
+     */
+    public void display() {
+        System.out.println(this.toString());
+    }
+
+    /**
+     * Deletes the first occurrence of the specified element in the sorted linked list.
+     * @param value the value to be deleted
+     * @return true if the element is found and deleted, false otherwise
+     */
+    public boolean delete(int value) {
+        if (this.head == null) {
+            return false;
+        } else if (this.head.value == value) {
+            if (this.head.next == null) {
+                this.head = null;
+                this.tail = null;
+            } else {
+                this.head = this.head.next;
+            }
+            return true;
+        } else {
+            Node temp = this.head;
+            while (temp.next != null) {
+                if (temp.next.value == value) {
+                    if (temp.next == this.tail) {
+                        this.tail = temp;
+                    }
+                    temp.next = temp.next.next;
+                    return true;
+                }
+                temp = temp.next;
+            }
+            return false;
+        }
+    }
+
+    /**
+     * Searches for the specified element in the sorted linked list.
+     * @param value the value to be searched
+     * @return true if the element is found, false otherwise
+     */
+    public boolean search(int value) {
+        Node temp = this.head;
+        while (temp != null) {
+            if (temp.value == value) {
+                return true;
+            }
+            temp = temp.next;
+        }
+        return false;
+    }
+
+    /**
+     * Checks if the sorted linked list is empty.
+     * @return true if the list is empty, false otherwise
+     */
+    public boolean isEmpty() {
+        return head == null;
+    }
+    /**
+     * Returns a string representation of the sorted linked list.
+     * @return a string representation of the sorted linked list
+     */
+    @Override
+    public String toString() {
+        if (this.head != null) {
+            List<String> elements = new ArrayList<>();
+            Node temp = this.head;
+            while (temp != null) {
+                elements.add(String.valueOf(temp.value));
+                temp = temp.next;
+            }
+            return "[" + String.join(", ", elements) + "]";
+
+        } else {
+            return "[]";
+        }
+    }
+
+    public final class Node {
+        public final int value;
+        public Node next;
+
+        public Node(int value) {
+            this.value = value;
+            this.next = null;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java
new file mode 100644
index 000000000000..4877e6db4ec4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java
@@ -0,0 +1,67 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class SortedLinkedListTest {
+
+    @Test
+    public void testInsert() {
+        SortedLinkedList list = new SortedLinkedList();
+        list.insert(5);
+        list.insert(3);
+        list.insert(7);
+        assertEquals("[3, 5, 7]", list.toString());
+    }
+
+    @Test
+    public void testDelete() {
+        SortedLinkedList list = new SortedLinkedList();
+        list.insert(5);
+        list.insert(3);
+        list.insert(7);
+        assertTrue(list.delete(5));
+        assertEquals("[3, 7]", list.toString());
+        assertFalse(list.delete(10));
+    }
+
+    @Test
+    public void testSearch() {
+        SortedLinkedList list = new SortedLinkedList();
+        list.insert(5);
+        list.insert(3);
+        list.insert(7);
+        assertTrue(list.search(5));
+        assertFalse(list.search(10));
+    }
+    @Test
+    public void testEmptyList() {
+        SortedLinkedList list = new SortedLinkedList();
+        assertEquals("[]", list.toString());
+        assertFalse(list.delete(5));
+        assertFalse(list.search(5));
+    }
+    @Test
+    public void testIsEmptyOnEmptyList() {
+        SortedLinkedList list = new SortedLinkedList();
+        assertTrue(list.isEmpty());
+    }
+
+    @Test
+    public void testIsEmptyOnNonEmptyList() {
+        SortedLinkedList list = new SortedLinkedList();
+        list.insert(10);
+        assertFalse(list.isEmpty());
+    }
+
+    @Test
+    public void testIsEmptyAfterDeletion() {
+        SortedLinkedList list = new SortedLinkedList();
+        list.insert(10);
+        list.delete(10);
+        assertTrue(list.isEmpty());
+    }
+}

From ea0ed2396114133b1396c443551503fef7fedb4d Mon Sep 17 00:00:00 2001
From: Sailok Chinta <sailokchinta2012@gmail.com>
Date: Thu, 3 Oct 2024 12:12:38 +0530
Subject: [PATCH 0406/1338] feat: removing duplicate implementation of Dutch
 National Flag Sort Algorithm (#5539)

feat: removing duplicate implementation of Dutch National Flag Sort Implementation

Co-authored-by: sailok.chinta <sailok.chinta@kotak.com>
---
 .../java/com/thealgorithms/sorts/DNFSort.java | 56 -------------------
 1 file changed, 56 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/sorts/DNFSort.java

diff --git a/src/main/java/com/thealgorithms/sorts/DNFSort.java b/src/main/java/com/thealgorithms/sorts/DNFSort.java
deleted file mode 100644
index 4b1e913cf3e0..000000000000
--- a/src/main/java/com/thealgorithms/sorts/DNFSort.java
+++ /dev/null
@@ -1,56 +0,0 @@
-package com.thealgorithms.sorts;
-
-public final class DNFSort {
-    private DNFSort() {
-    }
-
-    // Sort the input array, the array is assumed to
-    // have values in {0, 1, 2}
-    static void sort012(int[] a, int arrSize) {
-        int low = 0;
-        int high = arrSize - 1;
-        int mid = 0;
-        int temp;
-        while (mid <= high) {
-            switch (a[mid]) {
-            case 0:
-                temp = a[low];
-                a[low] = a[mid];
-                a[mid] = temp;
-                low++;
-                mid++;
-                break;
-
-            case 1:
-                mid++;
-                break;
-            case 2:
-                temp = a[mid];
-                a[mid] = a[high];
-                a[high] = temp;
-                high--;
-                break;
-
-            default:
-                throw new IllegalArgumentException("Unexpected value: " + a[mid]);
-            }
-        }
-    }
-
-    /* Utility function to print array arr[] */
-    static void printArray(int[] arr, int arrSize) {
-        for (int i = 0; i < arrSize; i++) {
-            System.out.print(arr[i] + " ");
-        }
-        System.out.println();
-    }
-
-    /*Driver function to check for above functions*/
-    public static void main(String[] args) {
-        int[] arr = {0, 1, 1, 0, 1, 2, 1, 2, 0, 0, 0, 1};
-        int arrSize = arr.length;
-        sort012(arr, arrSize);
-        System.out.println("Array after seggregation ");
-        printArray(arr, arrSize);
-    }
-}

From ce6d98f8da22032c8eee9dfe2289c4d3024d0610 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 3 Oct 2024 12:37:44 +0530
Subject: [PATCH 0407/1338] Add Merge Intervals algorithm (#5516)

---
 DIRECTORY.md                                  |  9 ++-
 .../greedyalgorithms/MergeIntervals.java      | 64 +++++++++++++++++
 .../greedyalgorithms/MergeIntervalsTest.java  | 71 +++++++++++++++++++
 3 files changed, 143 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6f63a88b085a..6e985fe2f799 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -156,6 +156,7 @@
               * [SearchSinglyLinkedListRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java)
               * [SinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java)
               * [SkipList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java)
+              * [SortedLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java)
             * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/Node.java)
             * queues
               * [CircularQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java)
@@ -268,6 +269,7 @@
             * [FractionalKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
             * [GaleShapley](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java)
             * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
+            * [MergeIntervals](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java)
             * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java)
           * io
             * [BufferedReader](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/io/BufferedReader.java)
@@ -451,6 +453,8 @@
             * [TowerOfHanoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TowerOfHanoi.java)
             * [TwoPointers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TwoPointers.java)
             * [Verhoeff](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Verhoeff.java)
+          * Recursion
+            * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java)
           * scheduling
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
@@ -500,7 +504,6 @@
             * [CombSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CombSort.java)
             * [CountingSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CountingSort.java)
             * [CycleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CycleSort.java)
-            * [DNFSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DNFSort.java)
             * [DualPivotQuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java)
             * [DutchNationalFlagSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java)
             * [ExchangeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/ExchangeSort.java)
@@ -685,6 +688,7 @@
               * [RotateSinglyLinkedListsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java)
               * [SinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java)
               * [SkipListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java)
+              * [SortedLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java)
             * queues
               * [CircularQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java)
               * [DequeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java)
@@ -754,6 +758,7 @@
             * [FractionalKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
             * [GaleShapleyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java)
             * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
+            * [MergeIntervalsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java)
             * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java)
           * io
             * [BufferedReaderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/io/BufferedReaderTest.java)
@@ -893,6 +898,8 @@
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
+          * Recursion
+            * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java)
           * scheduling
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java b/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java
new file mode 100644
index 000000000000..07bd0b73326f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java
@@ -0,0 +1,64 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Problem Statement:
+ * Given an array of intervals where intervals[i] = [starti, endi].
+ *
+ * Merge all overlapping intervals and return an array of the non-overlapping
+ * intervals
+ * that cover all the intervals in the input.
+ */
+public final class MergeIntervals {
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private MergeIntervals() {
+    }
+
+    /**
+     * Merges overlapping intervals from the given array of intervals.
+     *
+     * The method sorts the intervals by their start time, then iterates through the
+     * sorted intervals
+     * and merges overlapping intervals. If an interval overlaps with the last
+     * merged interval,
+     * it updates the end time of the last merged interval. Otherwise, it adds the
+     * interval as a new entry.
+     *
+     * @param intervals A 2D array representing intervals where each element is an
+     *                  interval [starti, endi].
+     * @return A 2D array of merged intervals where no intervals overlap.
+     *
+     *         Example:
+     *         Input: {{1, 3}, {2, 6}, {8, 10}, {15, 18}}
+     *         Output: {{1, 6}, {8, 10}, {15, 18}}
+     */
+    public static int[][] merge(int[][] intervals) {
+        // Sort the intervals by their start time (ascending order)
+        Arrays.sort(intervals, (a, b) -> Integer.compare(a[0], b[0]));
+
+        // List to store merged intervals
+        List<int[]> merged = new ArrayList<>();
+
+        for (int[] interval : intervals) { // Each interval
+            // If the merged list is empty or the current interval does not overlap with
+            // the last merged interval, add it to the merged list.
+            if (merged.isEmpty() || interval[0] > merged.get(merged.size() - 1)[1]) {
+                merged.add(interval);
+            } else {
+                // If there is an overlap, merge the intervals by updating the end time
+                // of the last merged interval to the maximum end time between the two
+                // intervals.
+                merged.get(merged.size() - 1)[1] = Math.max(merged.get(merged.size() - 1)[1], interval[1]);
+            }
+        }
+
+        // Convert the list of merged intervals back to a 2D array and return it
+        return merged.toArray(new int[merged.size()][]);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java
new file mode 100644
index 000000000000..0135f9d73260
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java
@@ -0,0 +1,71 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class MergeIntervalsTest {
+
+    @Test
+    public void testMergeIntervalsWithOverlappingIntervals() {
+        // Test case where some intervals overlap and should be merged
+        int[][] intervals = {{1, 3}, {2, 6}, {8, 10}, {15, 18}};
+        int[][] expected = {{1, 6}, {8, 10}, {15, 18}};
+        int[][] result = MergeIntervals.merge(intervals);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testMergeIntervalsWithNoOverlap() {
+        // Test case where intervals do not overlap
+        int[][] intervals = {{1, 2}, {3, 4}, {5, 6}};
+        int[][] expected = {{1, 2}, {3, 4}, {5, 6}};
+        int[][] result = MergeIntervals.merge(intervals);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testMergeIntervalsWithCompleteOverlap() {
+        // Test case where intervals completely overlap
+        int[][] intervals = {{1, 5}, {2, 4}, {3, 6}};
+        int[][] expected = {{1, 6}};
+        int[][] result = MergeIntervals.merge(intervals);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testMergeIntervalsWithSingleInterval() {
+        // Test case where only one interval is given
+        int[][] intervals = {{1, 2}};
+        int[][] expected = {{1, 2}};
+        int[][] result = MergeIntervals.merge(intervals);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testMergeIntervalsWithEmptyArray() {
+        // Test case where the input array is empty
+        int[][] intervals = {};
+        int[][] expected = {};
+        int[][] result = MergeIntervals.merge(intervals);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testMergeIntervalsWithIdenticalIntervals() {
+        // Test case where multiple identical intervals are given
+        int[][] intervals = {{1, 3}, {1, 3}, {1, 3}};
+        int[][] expected = {{1, 3}};
+        int[][] result = MergeIntervals.merge(intervals);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testMergeIntervalsWithRandomIntervals() {
+        // Test case with a mix of overlapping and non-overlapping intervals
+        int[][] intervals = {{1, 4}, {5, 7}, {2, 6}, {8, 10}};
+        int[][] expected = {{1, 7}, {8, 10}};
+        int[][] result = MergeIntervals.merge(intervals);
+        assertArrayEquals(expected, result);
+    }
+}

From 7b934af257208f0dc1a06ba5d2e74ee808f78387 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 3 Oct 2024 12:40:59 +0530
Subject: [PATCH 0408/1338] Improve comments, add function documentation in
 BinarySearch2dArray.java (#5518)

---
 .../searches/BinarySearch2dArray.java         | 94 +++++++++++++------
 1 file changed, 67 insertions(+), 27 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java b/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
index 53f5d7c8434e..aa938447b864 100644
--- a/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
+++ b/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java
@@ -1,87 +1,127 @@
 package com.thealgorithms.searches;
 
-/*
-To apply this method, the provided array must be strictly sorted. In this method, two pointers, one
-at 0th row & the other at the last row are taken & the searching is done on the basis of the middle
-element of the middle column. If that element is equal to target, its coordinates are returned, else
-if it is smaller than the target, the rows above that element are ignored (because the elements
-above it will also be smaller than the target), else that element is greater than the target, then
-the rows below it are ignored.
+/**
+ * This class provides a method to search for a target value in a 2D sorted
+ * array.
+ * The search is performed using a combination of binary search on rows and
+ * columns.
+ * The 2D array must be strictly sorted in both rows and columns.
+ *
+ * The algorithm works by:
+ * 1. Performing a binary search on the middle column of the 2D array.
+ * 2. Depending on the value found, it eliminates rows above or below the middle
+ * element.
+ * 3. After finding or eliminating rows, it further applies binary search in the
+ * relevant columns.
  */
 public final class BinarySearch2dArray {
+
     private BinarySearch2dArray() {
     }
 
+    /**
+     * Performs a binary search on a 2D sorted array to find the target value.
+     * The array must be sorted in ascending order in both rows and columns.
+     *
+     * @param arr    The 2D array to search in.
+     * @param target The value to search for.
+     * @return An array containing the row and column indices of the target, or [-1,
+     *         -1] if the target is not found.
+     */
     static int[] binarySearch(int[][] arr, int target) {
         int rowCount = arr.length;
         int colCount = arr[0].length;
 
+        // Edge case: If there's only one row, search that row directly.
         if (rowCount == 1) {
             return binarySearch(arr, target, 0, 0, colCount);
         }
 
+        // Set initial boundaries for binary search on rows.
         int startRow = 0;
         int endRow = rowCount - 1;
-        int midCol = colCount / 2;
+        int midCol = colCount / 2; // Middle column index for comparison.
 
+        // Perform binary search on rows based on the middle column.
         while (startRow < endRow - 1) {
-            int midRow = startRow + (endRow - startRow) / 2; // getting the index of middle row
+            int midRow = startRow + (endRow - startRow) / 2;
 
+            // If the middle element matches the target, return its position.
             if (arr[midRow][midCol] == target) {
                 return new int[] {midRow, midCol};
-            } else if (arr[midRow][midCol] < target) {
+            }
+            // If the middle element is smaller than the target, discard the upper half.
+            else if (arr[midRow][midCol] < target) {
                 startRow = midRow;
-            } else {
+            }
+            // If the middle element is larger than the target, discard the lower half.
+            else {
                 endRow = midRow;
             }
         }
-        /*
-            if the above search fails to find the target element, these conditions will be used to
-           find the target element, which further uses the binary search algorithm in the places
-           which were left unexplored.
-             */
+
+        // If the target wasn't found during the row search, check the middle column of
+        // startRow and endRow.
         if (arr[startRow][midCol] == target) {
-            return new int[] {
-                startRow,
-                midCol,
-            };
+            return new int[] {startRow, midCol};
         }
 
         if (arr[endRow][midCol] == target) {
             return new int[] {endRow, midCol};
         }
 
+        // If target is smaller than the element in the left of startRow, perform a
+        // binary search on the left of startRow.
         if (target <= arr[startRow][midCol - 1]) {
             return binarySearch(arr, target, startRow, 0, midCol - 1);
         }
 
+        // If target is between midCol and the last column of startRow, perform a binary
+        // search on that part of the row.
         if (target >= arr[startRow][midCol + 1] && target <= arr[startRow][colCount - 1]) {
             return binarySearch(arr, target, startRow, midCol + 1, colCount - 1);
         }
 
+        // If target is smaller than the element in the left of endRow, perform a binary
+        // search on the left of endRow.
         if (target <= arr[endRow][midCol - 1]) {
             return binarySearch(arr, target, endRow, 0, midCol - 1);
         } else {
+            // Otherwise, search on the right of endRow.
             return binarySearch(arr, target, endRow, midCol + 1, colCount - 1);
         }
     }
 
+    /**
+     * Performs a binary search on a specific row of the 2D array.
+     *
+     * @param arr      The 2D array to search in.
+     * @param target   The value to search for.
+     * @param row      The row index where the target will be searched.
+     * @param colStart The starting column index for the search.
+     * @param colEnd   The ending column index for the search.
+     * @return An array containing the row and column indices of the target, or [-1,
+     *         -1] if the target is not found.
+     */
     static int[] binarySearch(int[][] arr, int target, int row, int colStart, int colEnd) {
+        // Perform binary search within the specified column range.
         while (colStart <= colEnd) {
             int midIndex = colStart + (colEnd - colStart) / 2;
 
+            // If the middle element matches the target, return its position.
             if (arr[row][midIndex] == target) {
-                return new int[] {
-                    row,
-                    midIndex,
-                };
-            } else if (arr[row][midIndex] < target) {
+                return new int[] {row, midIndex};
+            }
+            // If the middle element is smaller than the target, move to the right half.
+            else if (arr[row][midIndex] < target) {
                 colStart = midIndex + 1;
-            } else {
+            }
+            // If the middle element is larger than the target, move to the left half.
+            else {
                 colEnd = midIndex - 1;
             }
         }
 
-        return new int[] {-1, -1};
+        return new int[] {-1, -1}; // Target not found
     }
 }

From 48a298028dc5c0fe3c090372003a626d24ffc3c7 Mon Sep 17 00:00:00 2001
From: Sailok Chinta <sailokchinta2012@gmail.com>
Date: Thu, 3 Oct 2024 16:21:34 +0530
Subject: [PATCH 0409/1338] feat: Remove duplicate implementation of Dutch
 National Flag Sort Algorithm (#5541)

* feat: Remove duplicate implementation of Dutch National Flag Sort Algorithm

* feat: update DIRECTORY.md

---------

Co-authored-by: sailok.chinta <sailok.chinta@kotak.com>
---
 DIRECTORY.md                                  |  1 -
 .../java/com/thealgorithms/misc/Sort012D.java | 63 -------------------
 2 files changed, 64 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/misc/Sort012D.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6e985fe2f799..24cd22f67d07 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -399,7 +399,6 @@
             * [PalindromePrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromePrime.java)
             * [PalindromeSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java)
             * [RangeInSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java)
-            * [Sort012D](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sort012D.java)
             * [Sparsity](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sparsity.java)
             * [ThreeSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java)
             * [TwoSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/TwoSumProblem.java)
diff --git a/src/main/java/com/thealgorithms/misc/Sort012D.java b/src/main/java/com/thealgorithms/misc/Sort012D.java
deleted file mode 100644
index 706e877e40c1..000000000000
--- a/src/main/java/com/thealgorithms/misc/Sort012D.java
+++ /dev/null
@@ -1,63 +0,0 @@
-package com.thealgorithms.misc;
-
-import java.util.Scanner;
-
-/**
- * The array is divided into four sections: a[1..Lo-1] zeroes a[Lo..Mid-1] ones
- * a[Mid..Hi] unknown a[Hi+1..N] twos If array [mid] =0, then swap array [mid]
- * with array [low] and increment both pointers once. If array [mid] = 1, then
- * no swapping is required. Increment mid pointer once. If array [mid] = 2, then
- * we swap array [mid] with array [high] and decrement the high pointer once.
- * For more information on the Dutch national flag algorithm refer
- * https://en.wikipedia.org/wiki/Dutch_national_flag_problem
- */
-public final class Sort012D {
-    private Sort012D() {
-    }
-
-    public static void main(String[] args) {
-        Scanner np = new Scanner(System.in);
-        int n = np.nextInt();
-        int[] a = new int[n];
-        for (int i = 0; i < n; i++) {
-            a[i] = np.nextInt();
-        }
-        sort012(a);
-        np.close();
-    }
-
-    public static void sort012(int[] a) {
-        int l = 0;
-        int h = a.length - 1;
-        int mid = 0;
-        int temp;
-        while (mid <= h) {
-            switch (a[mid]) {
-            case 0:
-                temp = a[l];
-                a[l] = a[mid];
-                a[mid] = temp;
-                l++;
-                mid++;
-                break;
-
-            case 1:
-                mid++;
-                break;
-            case 2:
-                temp = a[mid];
-                a[mid] = a[h];
-                a[h] = temp;
-                h--;
-                break;
-
-            default:
-                throw new IllegalArgumentException("Unexpected value: " + a[mid]);
-            }
-        }
-        System.out.println("the Sorted array is ");
-        for (int i = 0; i < a.length; i++) {
-            System.out.print(+a[i] + " ");
-        }
-    }
-}

From be8df2188c716389de5150487c0862b80d88bd4e Mon Sep 17 00:00:00 2001
From: Tejaswi Tyagi <98461855+tejaswi0910@users.noreply.github.com>
Date: Thu, 3 Oct 2024 18:34:49 +0530
Subject: [PATCH 0410/1338] Adds Longest Arithmetic Subsequence Implementation
 (#5501)

* Added LongestArthmeticSubsequence

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../LongestArithmeticSubsequence.java         | 42 +++++++++++++++++++
 .../LongestArithmeticSubsequenceTest.java     | 35 ++++++++++++++++
 2 files changed, 77 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequenceTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java
new file mode 100644
index 000000000000..b5ac62b4674b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java
@@ -0,0 +1,42 @@
+package com.thealgorithms.dynamicprogramming;
+
+import java.util.HashMap;
+
+final class LongestArithmeticSubsequence {
+    private LongestArithmeticSubsequence() {
+    }
+
+    /**
+     * Returns the length of the longest arithmetic subsequence in the given array.
+     *
+     * A sequence seq is arithmetic if seq[i + 1] - seq[i] are all the same value
+     * (for 0 <= i < seq.length - 1).
+     *
+     * @param nums the input array of integers
+     * @return the length of the longest arithmetic subsequence
+     */
+    public static int getLongestArithmeticSubsequenceLength(int[] nums) {
+        if (nums == null) {
+            throw new IllegalArgumentException("Input array cannot be null");
+        }
+
+        if (nums.length <= 1) {
+            return nums.length;
+        }
+
+        HashMap<Integer, Integer>[] dp = new HashMap[nums.length];
+        int maxLength = 2;
+
+        // fill the dp array
+        for (int i = 0; i < nums.length; i++) {
+            dp[i] = new HashMap<>();
+            for (int j = 0; j < i; j++) {
+                final int diff = nums[i] - nums[j];
+                dp[i].put(diff, dp[j].getOrDefault(diff, 1) + 1);
+                maxLength = Math.max(maxLength, dp[i].get(diff));
+            }
+        }
+
+        return maxLength;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequenceTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequenceTest.java
new file mode 100644
index 000000000000..6384fe2afebe
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequenceTest.java
@@ -0,0 +1,35 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.apache.commons.lang3.ArrayUtils;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class LongestArithmeticSubsequenceTest {
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testGetLongestArithmeticSubsequenceLength(int[] nums, int expected) {
+        assertEquals(expected, LongestArithmeticSubsequence.getLongestArithmeticSubsequenceLength(nums));
+    }
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testGetLongestArithmeticSubsequenceLengthReversedInput(int[] nums, int expected) {
+        ArrayUtils.reverse(nums);
+        assertEquals(expected, LongestArithmeticSubsequence.getLongestArithmeticSubsequenceLength(nums));
+    }
+
+    @Test
+    void testGetLongestArithmeticSubsequenceLengthThrowsForNullInput() {
+        assertThrows(IllegalArgumentException.class, () -> LongestArithmeticSubsequence.getLongestArithmeticSubsequenceLength(null));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new int[] {3, 6, 9, 12, 15}, 5), Arguments.of(new int[] {1, 7, 10, 13, 14, 19}, 4), Arguments.of(new int[] {1, 2, 3, 4}, 4), Arguments.of(new int[] {}, 0), Arguments.of(new int[] {10}, 1), Arguments.of(new int[] {9, 4, 7, 2, 10}, 3),
+            Arguments.of(new int[] {1, 2, 2, 2, 2, 5}, 4));
+    }
+}

From 66ee59cbafac1fca68094a67b925ba6a12638571 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 4 Oct 2024 20:58:03 +0530
Subject: [PATCH 0411/1338] Add function documentation in `Sudoku.java` (#5532)

* Add function documentation and parameterized tests to Sudoku.java

* Update directory

* Update directory

* Fix clang format errors

* Change

* Fix

* Fix

* Fix

* Fix

* Fix

* Fix

* Fix

* Remove extra line

* Change values

* Fix

* Remove test

* Update directory

* Small comment fix

* Add comment

* Generalize comment

* Fix comment

* Update directory

* Fix comment

* Add changes suggested

---------

Co-authored-by: Hardvan <Hardvan@users.noreply.github.com>
---
 DIRECTORY.md                                  |  2 +
 .../java/com/thealgorithms/others/Sudoku.java | 83 ++++++++++++++-----
 2 files changed, 65 insertions(+), 20 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 24cd22f67d07..af5905d00747 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -238,6 +238,7 @@
             * [KnapsackMemoization](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java)
             * [LevenshteinDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java)
             * [LongestAlternatingSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java)
+            * [LongestArithmeticSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java)
             * [LongestCommonSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java)
             * [LongestIncreasingSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java)
             * [LongestPalindromicSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java)
@@ -733,6 +734,7 @@
             * [KnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
             * [LevenshteinDistanceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
             * [LongestAlternatingSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java)
+            * [LongestArithmeticSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequenceTest.java)
             * [LongestIncreasingSubsequenceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java)
             * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java)
             * [LongestValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java)
diff --git a/src/main/java/com/thealgorithms/others/Sudoku.java b/src/main/java/com/thealgorithms/others/Sudoku.java
index 0839a376c5de..0e88aee46f4d 100644
--- a/src/main/java/com/thealgorithms/others/Sudoku.java
+++ b/src/main/java/com/thealgorithms/others/Sudoku.java
@@ -1,33 +1,47 @@
 package com.thealgorithms.others;
 
+/**
+ * A class that provides methods to solve Sudoku puzzles of any n x n size
+ * using a backtracking approach, where n must be a perfect square.
+ * The algorithm checks for safe number placements in rows, columns,
+ * and subgrids (which are sqrt(n) x sqrt(n) in size) and recursively solves the puzzle.
+ * Though commonly used for 9x9 grids, it is adaptable to other valid Sudoku dimensions.
+ */
 final class Sudoku {
+
     private Sudoku() {
     }
 
+    /**
+     * Checks if placing a number in a specific position on the Sudoku board is safe.
+     * The number is considered safe if it does not violate any of the Sudoku rules:
+     * - It should not be present in the same row.
+     * - It should not be present in the same column.
+     * - It should not be present in the corresponding 3x3 subgrid.
+     * - It should not be present in the corresponding subgrid, which is sqrt(n) x sqrt(n) in size (e.g., for a 9x9 grid, the subgrid will be 3x3).
+     *
+     * @param board The current state of the Sudoku board.
+     * @param row   The row index where the number is to be placed.
+     * @param col   The column index where the number is to be placed.
+     * @param num   The number to be placed on the board.
+     * @return True if the placement is safe, otherwise false.
+     */
     public static boolean isSafe(int[][] board, int row, int col, int num) {
-        // Row has the unique (row-clash)
+        // Check the row for duplicates
         for (int d = 0; d < board.length; d++) {
-            // Check if the number we are trying to
-            // place is already present in
-            // that row, return false;
             if (board[row][d] == num) {
                 return false;
             }
         }
 
-        // Column has the unique numbers (column-clash)
+        // Check the column for duplicates
         for (int r = 0; r < board.length; r++) {
-            // Check if the number
-            // we are trying to
-            // place is already present in
-            // that column, return false;
             if (board[r][col] == num) {
                 return false;
             }
         }
 
-        // Corresponding square has
-        // unique number (box-clash)
+        // Check the corresponding 3x3 subgrid for duplicates
         int sqrt = (int) Math.sqrt(board.length);
         int boxRowStart = row - row % sqrt;
         int boxColStart = col - col % sqrt;
@@ -40,22 +54,37 @@ public static boolean isSafe(int[][] board, int row, int col, int num) {
             }
         }
 
-        // if there is no clash, it's safe
         return true;
     }
 
+    /**
+     * Solves the Sudoku puzzle using backtracking.
+     * The algorithm finds an empty cell and tries placing numbers
+     * from 1 to n, where n is the size of the board
+     * (for example, from 1 to 9 in a standard 9x9 Sudoku).
+     * The algorithm finds an empty cell and tries placing numbers from 1 to 9.
+     * The standard version of Sudoku uses numbers from 1 to 9, so the algorithm can be
+     * easily modified for other variations of the game.
+     * If a number placement is valid (checked via `isSafe`), the number is
+     * placed and the function recursively attempts to solve the rest of the puzzle.
+     * If no solution is possible, the number is removed (backtracked),
+     * and the process is repeated.
+     *
+     * @param board The current state of the Sudoku board.
+     * @param n     The size of the Sudoku board (typically 9 for a standard puzzle).
+     * @return True if the Sudoku puzzle is solvable, false otherwise.
+     */
     public static boolean solveSudoku(int[][] board, int n) {
         int row = -1;
         int col = -1;
         boolean isEmpty = true;
+
+        // Find the next empty cell
         for (int i = 0; i < n; i++) {
             for (int j = 0; j < n; j++) {
                 if (board[i][j] == 0) {
                     row = i;
                     col = j;
-
-                    // We still have some remaining
-                    // missing values in Sudoku
                     isEmpty = false;
                     break;
                 }
@@ -70,12 +99,12 @@ public static boolean solveSudoku(int[][] board, int n) {
             return true;
         }
 
-        // Else for each-row backtrack
+        // Try placing numbers 1 to n in the empty cell (n should be a perfect square)
+        // Eg: n=9 for a standard 9x9 Sudoku puzzle, n=16 for a 16x16 puzzle, etc.
         for (int num = 1; num <= n; num++) {
             if (isSafe(board, row, col, num)) {
                 board[row][col] = num;
                 if (solveSudoku(board, n)) {
-                    // print(board, n);
                     return true;
                 } else {
                     // replace it
@@ -86,8 +115,17 @@ public static boolean solveSudoku(int[][] board, int n) {
         return false;
     }
 
+    /**
+     * Prints the current state of the Sudoku board in a readable format.
+     * Each row is printed on a new line, with numbers separated by spaces.
+     *
+     * @param board The current state of the Sudoku board.
+     * @param n     The size of the Sudoku board (typically 9 for a standard puzzle).
+     */
     public static void print(int[][] board, int n) {
-        // We got the answer, just print it
+        // Print the board in a nxn grid format
+        // if n=9, print the board in a 9x9 grid format
+        // if n=16, print the board in a 16x16 grid format
         for (int r = 0; r < n; r++) {
             for (int d = 0; d < n; d++) {
                 System.out.print(board[r][d]);
@@ -101,7 +139,13 @@ public static void print(int[][] board, int n) {
         }
     }
 
-    // Driver Code
+    /**
+     * The driver method to demonstrate solving a Sudoku puzzle.
+     * A sample 9x9 Sudoku puzzle is provided, and the program attempts to solve it
+     * using the `solveSudoku` method. If a solution is found, it is printed to the console.
+     *
+     * @param args Command-line arguments (not used in this program).
+     */
     public static void main(String[] args) {
         int[][] board = new int[][] {
             {3, 0, 6, 5, 0, 8, 4, 0, 0},
@@ -117,7 +161,6 @@ public static void main(String[] args) {
         int n = board.length;
 
         if (solveSudoku(board, n)) {
-            // print solution
             print(board, n);
         } else {
             System.out.println("No solution");

From 41f767ef94e031bdd0b3709f23e97d2152b6e1a8 Mon Sep 17 00:00:00 2001
From: Luiz Carlos Jr <lcsjuniorsi@gmail.com>
Date: Fri, 4 Oct 2024 13:10:18 -0300
Subject: [PATCH 0412/1338] Add XOR Cipher (#5490)

---
 DIRECTORY.md                                  |  2 +
 .../com/thealgorithms/ciphers/XORCipher.java  | 41 +++++++++++++++++++
 .../thealgorithms/ciphers/XORCipherTest.java  | 34 +++++++++++++++
 3 files changed, 77 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/XORCipher.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/XORCipherTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index af5905d00747..a05dc8c07415 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -52,6 +52,7 @@
             * [RSA](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/RSA.java)
             * [SimpleSubCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/SimpleSubCipher.java)
             * [Vigenere](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Vigenere.java)
+            * [XORCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/XORCipher.java)
           * conversions
             * [AffineConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AffineConverter.java)
             * [AnyBaseToAnyBase](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java)
@@ -619,6 +620,7 @@
             * [RSATest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RSATest.java)
             * [SimpleSubCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/SimpleSubCipherTest.java)
             * [VigenereTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/VigenereTest.java)
+            * [XORCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/XORCipherTest.java)
           * conversions
             * [AnyBaseToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java)
             * [BinaryToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java)
diff --git a/src/main/java/com/thealgorithms/ciphers/XORCipher.java b/src/main/java/com/thealgorithms/ciphers/XORCipher.java
new file mode 100644
index 000000000000..c4410d8c77ba
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/XORCipher.java
@@ -0,0 +1,41 @@
+package com.thealgorithms.ciphers;
+
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.HexFormat;
+
+/**
+ * A simple implementation of XOR cipher that, given a key, allows to encrypt and decrypt a plaintext.
+ *
+ * @author <a href="https://github.com/lcsjunior">lcsjunior</a>
+ *
+ */
+public final class XORCipher {
+
+    private static final Charset CS_DEFAULT = StandardCharsets.UTF_8;
+
+    private XORCipher() {
+    }
+
+    public static byte[] xor(final byte[] inputBytes, final byte[] keyBytes) {
+        byte[] outputBytes = new byte[inputBytes.length];
+        for (int i = 0; i < inputBytes.length; ++i) {
+            outputBytes[i] = (byte) (inputBytes[i] ^ keyBytes[i % keyBytes.length]);
+        }
+        return outputBytes;
+    }
+
+    public static String encrypt(final String plainText, final String key) {
+        byte[] plainTextBytes = plainText.getBytes(CS_DEFAULT);
+        byte[] keyBytes = key.getBytes(CS_DEFAULT);
+        byte[] xorResult = xor(plainTextBytes, keyBytes);
+        return HexFormat.of().formatHex(xorResult);
+    }
+
+    public static String decrypt(final String cipherText, final String key) {
+        byte[] cipherBytes = HexFormat.of().parseHex(cipherText);
+        byte[] keyBytes = key.getBytes(CS_DEFAULT);
+        byte[] xorResult = xor(cipherBytes, keyBytes);
+        return new String(xorResult, CS_DEFAULT);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/XORCipherTest.java b/src/test/java/com/thealgorithms/ciphers/XORCipherTest.java
new file mode 100644
index 000000000000..15e27d5d6778
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/XORCipherTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class XORCipherTest {
+
+    @Test
+    void xorEncryptTest() {
+        // given
+        String plaintext = "My t&xt th@t will be ençrypted...";
+        String key = "My ç&cret key!";
+
+        // when
+        String cipherText = XORCipher.encrypt(plaintext, key);
+
+        // then
+        assertEquals("000000b7815e1752111c601f450e48211500a1c206061ca6d35212150d4429570eed", cipherText);
+    }
+
+    @Test
+    void xorDecryptTest() {
+        // given
+        String cipherText = "000000b7815e1752111c601f450e48211500a1c206061ca6d35212150d4429570eed";
+        String key = "My ç&cret key!";
+
+        // when
+        String plainText = XORCipher.decrypt(cipherText, key);
+
+        // then
+        assertEquals("My t&xt th@t will be ençrypted...", plainText);
+    }
+}

From de22158b800814503d923e66ceec40790e2da78f Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 4 Oct 2024 21:56:18 +0530
Subject: [PATCH 0413/1338] Add tests for `SkylineAlgorithm.java` (#5556)

---
 DIRECTORY.md                                  |   1 +
 .../SkylineAlgorithmTest.java                 | 102 ++++++++++++++++++
 2 files changed, 103 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a05dc8c07415..3e210b57788e 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -725,6 +725,7 @@
               * [ZigzagTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/ZigzagTraversalTest.java)
           * divideandconquer
             * [BinaryExponentiationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java)
+            * [SkylineAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java)
             * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
           * dynamicprogramming
             * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
diff --git a/src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java b/src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java
new file mode 100644
index 000000000000..f85515110b70
--- /dev/null
+++ b/src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java
@@ -0,0 +1,102 @@
+package com.thealgorithms.divideandconquer;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class SkylineAlgorithmTest {
+
+    private SkylineAlgorithm skylineAlgorithm;
+
+    @BeforeEach
+    public void setUp() {
+        skylineAlgorithm = new SkylineAlgorithm();
+    }
+
+    @Test
+    public void testProduceSubSkyLinesSinglePoint() {
+        // Test with a single point
+        ArrayList<SkylineAlgorithm.Point> points = new ArrayList<>();
+        points.add(new SkylineAlgorithm.Point(1, 10));
+
+        ArrayList<SkylineAlgorithm.Point> result = skylineAlgorithm.produceSubSkyLines(points);
+
+        assertEquals(1, result.size());
+        assertEquals(1, result.get(0).getX());
+        assertEquals(10, result.get(0).getY());
+    }
+
+    @Test
+    public void testProduceSubSkyLinesTwoPoints() {
+        // Test with two points, one dominated by the other
+        ArrayList<SkylineAlgorithm.Point> points = new ArrayList<>();
+        points.add(new SkylineAlgorithm.Point(1, 10));
+        points.add(new SkylineAlgorithm.Point(1, 5));
+
+        ArrayList<SkylineAlgorithm.Point> result = skylineAlgorithm.produceSubSkyLines(points);
+
+        assertEquals(1, result.size());
+        assertEquals(1, result.get(0).getX());
+        assertEquals(5, result.get(0).getY());
+    }
+
+    @Test
+    public void testProduceSubSkyLinesMultiplePoints() {
+        // Test with more than two points
+        ArrayList<SkylineAlgorithm.Point> points = new ArrayList<>();
+        points.add(new SkylineAlgorithm.Point(1, 10));
+        points.add(new SkylineAlgorithm.Point(2, 15));
+        points.add(new SkylineAlgorithm.Point(3, 5));
+        points.add(new SkylineAlgorithm.Point(4, 20));
+
+        ArrayList<SkylineAlgorithm.Point> result = skylineAlgorithm.produceSubSkyLines(points);
+
+        assertEquals(2, result.size());
+
+        // Assert the correct points in skyline
+        assertEquals(1, result.get(0).getX());
+        assertEquals(10, result.get(0).getY());
+        assertEquals(3, result.get(1).getX());
+        assertEquals(5, result.get(1).getY());
+    }
+
+    @Test
+    public void testProduceFinalSkyLine() {
+        // Test merging two skylines
+        ArrayList<SkylineAlgorithm.Point> left = new ArrayList<>();
+        left.add(new SkylineAlgorithm.Point(1, 10));
+        left.add(new SkylineAlgorithm.Point(2, 5));
+
+        ArrayList<SkylineAlgorithm.Point> right = new ArrayList<>();
+        right.add(new SkylineAlgorithm.Point(3, 8));
+        right.add(new SkylineAlgorithm.Point(4, 3));
+
+        ArrayList<SkylineAlgorithm.Point> result = skylineAlgorithm.produceFinalSkyLine(left, right);
+
+        assertEquals(3, result.size());
+
+        // Assert the correct points in the final skyline
+        assertEquals(1, result.get(0).getX());
+        assertEquals(10, result.get(0).getY());
+        assertEquals(2, result.get(1).getX());
+        assertEquals(5, result.get(1).getY());
+        assertEquals(4, result.get(2).getX());
+        assertEquals(3, result.get(2).getY());
+    }
+
+    @Test
+    public void testXComparator() {
+        // Test the XComparator used for sorting the points
+        SkylineAlgorithm.XComparator comparator = new SkylineAlgorithm().new XComparator();
+
+        SkylineAlgorithm.Point p1 = new SkylineAlgorithm.Point(1, 10);
+        SkylineAlgorithm.Point p2 = new SkylineAlgorithm.Point(2, 5);
+
+        // Check if the XComparator sorts points by their x-value
+        assertEquals(-1, comparator.compare(p1, p2)); // p1.x < p2.x
+        assertEquals(1, comparator.compare(p2, p1)); // p2.x > p1.x
+        assertEquals(0, comparator.compare(p1, new SkylineAlgorithm.Point(1, 15))); // p1.x == p2.x
+    }
+}

From 5cbdb475ee3fdacbd59d4727d488fe2a74584c5b Mon Sep 17 00:00:00 2001
From: Muhammad Junaid Khalid <mjk22071998@gmail.com>
Date: Fri, 4 Oct 2024 21:28:36 +0500
Subject: [PATCH 0414/1338] Add digit separation for large integers (#5543)

---
 .../greedyalgorithms/DigitSeparation.java     | 40 ++++++++++
 .../greedyalgorithms/DigitSeparationTest.java | 78 +++++++++++++++++++
 2 files changed, 118 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java

diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java b/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java
new file mode 100644
index 000000000000..bee5f98cd2ee
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java
@@ -0,0 +1,40 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * This class provides methods to separate the digits of a large positive number into a list.
+ */
+public class DigitSeparation {
+    public DigitSeparation() {
+    }
+    /**
+     * Separates the digits of a large positive number into a list in reverse order.
+     * @param largeNumber The large number to separate digits from.
+     * @return A list of digits in reverse order.
+     */
+    public List<Long> digitSeparationReverseOrder(long largeNumber) {
+        List<Long> result = new ArrayList<>();
+        if (largeNumber != 0) {
+            while (largeNumber != 0) {
+                result.add(Math.abs(largeNumber % 10));
+                largeNumber = largeNumber / 10;
+            }
+        } else {
+            result.add(0L);
+        }
+        return result;
+    }
+    /**
+     * Separates the digits of a large positive number into a list in forward order.
+     * @param largeNumber The large number to separate digits from.
+     * @return A list of digits in forward order.
+     */
+    public List<Long> digitSeparationForwardOrder(long largeNumber) {
+        List<Long> result = this.digitSeparationReverseOrder(largeNumber);
+        Collections.reverse(result);
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java
new file mode 100644
index 000000000000..1fe018ecce18
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java
@@ -0,0 +1,78 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+public class DigitSeparationTest {
+
+    @Test
+    public void testDigitSeparationReverseOrderSingleDigit() {
+        DigitSeparation digitSeparation = new DigitSeparation();
+        List<Long> result = digitSeparation.digitSeparationReverseOrder(5);
+        assertEquals(List.of(5L), result);
+    }
+
+    @Test
+    public void testDigitSeparationReverseOrderMultipleDigits() {
+        DigitSeparation digitSeparation = new DigitSeparation();
+        List<Long> result = digitSeparation.digitSeparationReverseOrder(123);
+        assertEquals(List.of(3L, 2L, 1L), result);
+    }
+
+    @Test
+    public void testDigitSeparationReverseOrderLargeNumber() {
+        DigitSeparation digitSeparation = new DigitSeparation();
+        List<Long> result = digitSeparation.digitSeparationReverseOrder(123456789);
+        assertEquals(List.of(9L, 8L, 7L, 6L, 5L, 4L, 3L, 2L, 1L), result);
+    }
+
+    @Test
+    public void testDigitSeparationReverseOrderZero() {
+        DigitSeparation digitSeparation = new DigitSeparation();
+        List<Long> result = digitSeparation.digitSeparationReverseOrder(0);
+        assertEquals(List.of(0L), result);
+    }
+
+    @Test
+    public void testDigitSeparationReverseOrderNegativeNumbers() {
+        DigitSeparation digitSeparation = new DigitSeparation();
+        List<Long> result = digitSeparation.digitSeparationReverseOrder(-123);
+        assertEquals(List.of(3L, 2L, 1L), result);
+    }
+
+    @Test
+    public void testDigitSeparationForwardOrderSingleDigit() {
+        DigitSeparation digitSeparation = new DigitSeparation();
+        List<Long> result = digitSeparation.digitSeparationForwardOrder(5);
+        assertEquals(List.of(5L), result);
+    }
+
+    @Test
+    public void testDigitSeparationForwardOrderMultipleDigits() {
+        DigitSeparation digitSeparation = new DigitSeparation();
+        List<Long> result = digitSeparation.digitSeparationForwardOrder(123);
+        assertEquals(List.of(1L, 2L, 3L), result);
+    }
+
+    @Test
+    public void testDigitSeparationForwardOrderLargeNumber() {
+        DigitSeparation digitSeparation = new DigitSeparation();
+        List<Long> result = digitSeparation.digitSeparationForwardOrder(123456789);
+        assertEquals(List.of(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L), result);
+    }
+
+    @Test
+    public void testDigitSeparationForwardOrderZero() {
+        DigitSeparation digitSeparation = new DigitSeparation();
+        List<Long> result = digitSeparation.digitSeparationForwardOrder(0);
+        assertEquals(List.of(0L), result);
+    }
+
+    @Test
+    public void testDigitSeparationForwardOrderNegativeNumber() {
+        DigitSeparation digitSeparation = new DigitSeparation();
+        List<Long> result = digitSeparation.digitSeparationForwardOrder(-123);
+        assertEquals(List.of(1L, 2L, 3L), result);
+    }
+}

From b61c54797babbe46825586894d69715d8947d559 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 4 Oct 2024 22:10:44 +0530
Subject: [PATCH 0415/1338] Add `Infix To Prefix` new algorithm with unit tests
 (#5537)

* Add `Infix To Prefix` new algorithm

* Update directory

* Update directory

* Fix clang

* Fix clang

* Add more tests

* Fix comma error

* Fix test cases

* Fix comment

* Remove unused import

* Update directory

* Add tests for null & empty strings

* Implement suggested changes

* Update directory

* Fix comment

---------

Co-authored-by: Hardvan <Hardvan@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 DIRECTORY.md                                  |  4 +
 .../thealgorithms/stacks/InfixToPrefix.java   | 92 +++++++++++++++++++
 .../stacks/InfixToPrefixTest.java             | 44 +++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/InfixToPrefix.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 3e210b57788e..4fb916996aac 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -268,6 +268,7 @@
           * greedyalgorithms
             * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
             * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java)
+            * [DigitSeparation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java)
             * [FractionalKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
             * [GaleShapley](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java)
             * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
@@ -545,6 +546,7 @@
             * [DecimalToAnyUsingStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java)
             * [DuplicateBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java)
             * [InfixToPostfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java)
+            * [InfixToPrefix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java)
             * [LargestRectangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/LargestRectangle.java)
             * [MaximumMinimumWindow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java)
             * [NextGreaterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java)
@@ -759,6 +761,7 @@
           * greedyalgorithms
             * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
             * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java)
+            * [DigitSeparationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java)
             * [FractionalKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
             * [GaleShapleyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java)
             * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
@@ -976,6 +979,7 @@
             * [DecimalToAnyUsingStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/DecimalToAnyUsingStackTest.java)
             * [DuplicateBracketsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java)
             * [InfixToPostfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java)
+            * [InfixToPrefixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java)
             * [LargestRectangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java)
             * [NextGreaterElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java)
             * [NextSmallerElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
diff --git a/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java b/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java
new file mode 100644
index 000000000000..3d90d14e0d1e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java
@@ -0,0 +1,92 @@
+package com.thealgorithms.stacks;
+
+import java.util.Stack;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public final class InfixToPrefix {
+    private InfixToPrefix() {
+    }
+
+    /**
+     * Convert an infix expression to a prefix expression using stack.
+     *
+     * @param infixExpression the infix expression to convert
+     * @return the prefix expression
+     * @throws IllegalArgumentException if the infix expression has unbalanced brackets
+     * @throws NullPointerException     if the infix expression is null
+     */
+    public static String infix2Prefix(String infixExpression) throws IllegalArgumentException {
+        if (infixExpression == null) {
+            throw new NullPointerException("Input expression cannot be null.");
+        }
+        infixExpression = infixExpression.trim();
+        if (infixExpression.isEmpty()) {
+            return "";
+        }
+        if (!BalancedBrackets.isBalanced(filterBrackets(infixExpression))) {
+            throw new IllegalArgumentException("Invalid expression: unbalanced brackets.");
+        }
+
+        StringBuilder output = new StringBuilder();
+        Stack<Character> stack = new Stack<>();
+        // Reverse the infix expression for prefix conversion
+        String reversedInfix = new StringBuilder(infixExpression).reverse().toString();
+        for (char element : reversedInfix.toCharArray()) {
+            if (Character.isLetterOrDigit(element)) {
+                output.append(element);
+            } else if (element == ')') {
+                stack.push(element);
+            } else if (element == '(') {
+                while (!stack.isEmpty() && stack.peek() != ')') {
+                    output.append(stack.pop());
+                }
+                stack.pop();
+            } else {
+                while (!stack.isEmpty() && precedence(element) < precedence(stack.peek())) {
+                    output.append(stack.pop());
+                }
+                stack.push(element);
+            }
+        }
+        while (!stack.isEmpty()) {
+            output.append(stack.pop());
+        }
+
+        // Reverse the result to get the prefix expression
+        return output.reverse().toString();
+    }
+
+    /**
+     * Determines the precedence of an operator.
+     *
+     * @param operator the operator whose precedence is to be determined
+     * @return the precedence of the operator
+     */
+    private static int precedence(char operator) {
+        switch (operator) {
+        case '+':
+        case '-':
+            return 0;
+        case '*':
+        case '/':
+            return 1;
+        case '^':
+            return 2;
+        default:
+            return -1;
+        }
+    }
+
+    /**
+     * Filters out all characters from the input string except brackets.
+     *
+     * @param input the input string to filter
+     * @return a string containing only brackets from the input string
+     */
+    private static String filterBrackets(String input) {
+        Pattern pattern = Pattern.compile("[^(){}\\[\\]<>]");
+        Matcher matcher = pattern.matcher(input);
+        return matcher.replaceAll("");
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java b/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java
new file mode 100644
index 000000000000..91be8a63da62
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class InfixToPrefixTest {
+
+    @ParameterizedTest
+    @MethodSource("provideValidExpressions")
+    void testValidExpressions(String infix, String expectedPrefix) throws Exception {
+        assertEquals(expectedPrefix, InfixToPrefix.infix2Prefix(infix));
+    }
+
+    @Test
+    void testEmptyString() {
+        // Assuming that an empty string returns an empty prefix or throws an exception
+        assertEquals("", InfixToPrefix.infix2Prefix(""));
+    }
+
+    @Test
+    void testNullValue() {
+        // Assuming that a null input throws a NullPointerException
+        assertThrows(NullPointerException.class, () -> InfixToPrefix.infix2Prefix(null));
+    }
+
+    private static Stream<Arguments> provideValidExpressions() {
+        return Stream.of(Arguments.of("3+2", "+32"), // Simple addition
+            Arguments.of("1+(2+3)", "+1+23"), // Parentheses
+            Arguments.of("(3+4)*5-6", "-*+3456"), // Nested operations
+            Arguments.of("a+b*c", "+a*bc"), // Multiplication precedence
+            Arguments.of("a+b*c/d", "+a/*bcd"), // Division precedence
+            Arguments.of("a+b*c-d", "-+a*bcd"), // Subtraction precedence
+            Arguments.of("a+b*c/d-e", "-+a/*bcde"), // Mixed precedence
+            Arguments.of("a+b*(c-d)", "+a*b-cd"), // Parentheses precedence
+            Arguments.of("a+b*(c-d)/e", "+a/*b-cde") // Mixed precedence with parentheses
+        );
+    }
+}

From ea6457bf41afeafac648d519f8ebd1b8b37d457f Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 4 Oct 2024 22:28:52 +0530
Subject: [PATCH 0416/1338] Add `PrefixToInfix.java` new algorithm (#5552)

* Add `PrefixToInfix.java` new algorithm

* Update directory

* Fix clang error

* Update directory

* Fix comment

* Add suggested changes

---------

Co-authored-by: Hardvan <Hardvan@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 DIRECTORY.md                                  |  2 +
 .../thealgorithms/stacks/PrefixToInfix.java   | 69 +++++++++++++++++++
 .../stacks/PrefixToInfixTest.java             | 44 ++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/PrefixToInfix.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 4fb916996aac..3662a8cda5c2 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -552,6 +552,7 @@
             * [NextGreaterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java)
             * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
             * [PostfixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java)
+            * [PrefixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PrefixToInfix.java)
             * [StackPostfixNotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
           * strings
             * [AhoCorasick](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/AhoCorasick.java)
@@ -984,6 +985,7 @@
             * [NextGreaterElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java)
             * [NextSmallerElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
             * [PostfixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java)
+            * [PrefixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java)
             * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
           * strings
             * [AhoCorasickTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
diff --git a/src/main/java/com/thealgorithms/stacks/PrefixToInfix.java b/src/main/java/com/thealgorithms/stacks/PrefixToInfix.java
new file mode 100644
index 000000000000..41eb974b0e5b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/PrefixToInfix.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.stacks;
+
+import java.util.Stack;
+
+/**
+ * Converts a prefix expression to an infix expression using a stack.
+ *
+ * The input prefix expression should consist of
+ * valid operands (letters or digits) and operators (+, -, *, /, ^).
+ * Parentheses are not required in the prefix string.
+ */
+public final class PrefixToInfix {
+    private PrefixToInfix() {
+    }
+
+    /**
+     * Determines if a given character is a valid arithmetic operator.
+     *
+     * @param token the character to check
+     * @return true if the character is an operator, false otherwise
+     */
+    public static boolean isOperator(char token) {
+        return token == '+' || token == '-' || token == '/' || token == '*' || token == '^';
+    }
+
+    /**
+     * Converts a valid prefix expression to an infix expression.
+     *
+     * @param prefix the prefix expression to convert
+     * @return the equivalent infix expression
+     * @throws NullPointerException     if the prefix expression is null
+     */
+    public static String getPrefixToInfix(String prefix) {
+        if (prefix == null) {
+            throw new NullPointerException("Null prefix expression");
+        }
+        if (prefix.isEmpty()) {
+            return "";
+        }
+
+        Stack<String> stack = new Stack<>();
+
+        // Iterate over the prefix expression from right to left
+        for (int i = prefix.length() - 1; i >= 0; i--) {
+            char token = prefix.charAt(i);
+
+            if (isOperator(token)) {
+                // Pop two operands from stack
+                String operandA = stack.pop();
+                String operandB = stack.pop();
+
+                // Form the infix expression with parentheses
+                String infix = "(" + operandA + token + operandB + ")";
+
+                // Push the resulting infix expression back onto the stack
+                stack.push(infix);
+            } else {
+                // Push operand onto stack
+                stack.push(Character.toString(token));
+            }
+        }
+
+        if (stack.size() != 1) {
+            throw new ArithmeticException("Malformed prefix expression");
+        }
+
+        return stack.pop(); // final element on the stack is the full infix expression
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java b/src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java
new file mode 100644
index 000000000000..83fd09e1bbf6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class PrefixToInfixTest {
+
+    @ParameterizedTest
+    @MethodSource("provideValidPrefixToInfixTestCases")
+    void testValidPrefixToInfixConversion(String prefix, String expectedInfix) {
+        assertEquals(expectedInfix, PrefixToInfix.getPrefixToInfix(prefix));
+    }
+
+    static Stream<Arguments> provideValidPrefixToInfixTestCases() {
+        return Stream.of(Arguments.of("A", "A"), // Single operand
+            Arguments.of("+AB", "(A+B)"), // Addition
+            Arguments.of("*+ABC", "((A+B)*C)"), // Addition and multiplication
+            Arguments.of("-+A*BCD", "((A+(B*C))-D)"), // Mixed operators
+            Arguments.of("/-A*BC+DE", "((A-(B*C))/(D+E))"), // Mixed operators
+            Arguments.of("^+AB*CD", "((A+B)^(C*D))") // Mixed operators
+        );
+    }
+
+    @Test
+    void testEmptyPrefixExpression() {
+        assertEquals("", PrefixToInfix.getPrefixToInfix(""));
+    }
+
+    @Test
+    void testNullPrefixExpression() {
+        assertThrows(NullPointerException.class, () -> PrefixToInfix.getPrefixToInfix(null));
+    }
+
+    @Test
+    void testMalformedPrefixExpression() {
+        assertThrows(ArithmeticException.class, () -> PrefixToInfix.getPrefixToInfix("+ABC"));
+    }
+}

From 389d1d70d568f12b0aa0b838b9c3a42fa7647dbe Mon Sep 17 00:00:00 2001
From: Sailok Chinta <sailokchinta2012@gmail.com>
Date: Fri, 4 Oct 2024 22:43:40 +0530
Subject: [PATCH 0417/1338] feat: add conversion logic from integer to english
 (#5540)

* feat: add conversion logic from integer to english

* feat: update DIRECTORY.md

* feat: fix linting issues

* feat: fix build issue

* feat: address review comments

---------

Co-authored-by: sailok.chinta <sailok.chinta@kotak.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 DIRECTORY.md                                  |  1 +
 .../conversions/IntegerToEnglish.java         | 80 +++++++++++++++++++
 .../conversions/IntegerToEnglishTest.java     | 15 ++++
 3 files changed, 96 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 3662a8cda5c2..0b282d8fb747 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -68,6 +68,7 @@
             * [HexaDecimalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java)
             * [HexaDecimalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java)
             * [HexToOct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexToOct.java)
+            * [IntegerToEnglish] (https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java)
             * [IntegerToRoman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java)
             * [OctalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToBinary.java)
             * [OctalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java)
diff --git a/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java b/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java
new file mode 100644
index 000000000000..d3b938bf492d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java
@@ -0,0 +1,80 @@
+package com.thealgorithms.conversions;
+
+import java.util.Map;
+
+public final class IntegerToEnglish {
+    private static final Map<Integer, String> BASE_NUMBERS_MAP = Map.ofEntries(Map.entry(0, ""), Map.entry(1, "One"), Map.entry(2, "Two"), Map.entry(3, "Three"), Map.entry(4, "Four"), Map.entry(5, "Five"), Map.entry(6, "Six"), Map.entry(7, "Seven"), Map.entry(8, "Eight"), Map.entry(9, "Nine"),
+        Map.entry(10, "Ten"), Map.entry(11, "Eleven"), Map.entry(12, "Twelve"), Map.entry(13, "Thirteen"), Map.entry(14, "Fourteen"), Map.entry(15, "Fifteen"), Map.entry(16, "Sixteen"), Map.entry(17, "Seventeen"), Map.entry(18, "Eighteen"), Map.entry(19, "Nineteen"), Map.entry(20, "Twenty"),
+        Map.entry(30, "Thirty"), Map.entry(40, "Forty"), Map.entry(50, "Fifty"), Map.entry(60, "Sixty"), Map.entry(70, "Seventy"), Map.entry(80, "Eighty"), Map.entry(90, "Ninety"), Map.entry(100, "Hundred"));
+
+    private static final Map<Integer, String> THOUSAND_POWER_MAP = Map.ofEntries(Map.entry(1, "Thousand"), Map.entry(2, "Million"), Map.entry(3, "Billion"));
+
+    private IntegerToEnglish() {
+    }
+
+    /**
+        converts numbers < 1000 to english words
+     */
+    private static String convertToWords(int number) {
+        int remainder = number % 100;
+
+        String result;
+
+        if (remainder <= 20) {
+            result = BASE_NUMBERS_MAP.get(remainder);
+        } else if (BASE_NUMBERS_MAP.containsKey(remainder)) {
+            result = BASE_NUMBERS_MAP.get(remainder);
+        } else {
+            int tensDigit = remainder / 10;
+            int onesDigit = remainder % 10;
+
+            result = String.format("%s %s", BASE_NUMBERS_MAP.get(tensDigit * 10), BASE_NUMBERS_MAP.get(onesDigit));
+        }
+
+        int hundredsDigit = number / 100;
+
+        if (hundredsDigit > 0) {
+            result = String.format("%s %s%s", BASE_NUMBERS_MAP.get(hundredsDigit), BASE_NUMBERS_MAP.get(100), result.isEmpty() ? "" : " " + result);
+        }
+
+        return result;
+    }
+
+    /**
+      Only convert groups of three digit if they are non-zero
+     */
+    public static String integerToEnglishWords(int number) {
+        if (number == 0) {
+            return "Zero";
+        }
+
+        StringBuilder result = new StringBuilder();
+
+        int index = 0;
+
+        while (number > 0) {
+            int remainder = number % 1000;
+            number /= 1000;
+
+            if (remainder > 0) {
+                String subResult = convertToWords(remainder);
+
+                if (!subResult.isEmpty()) {
+                    if (!result.isEmpty()) {
+                        result.insert(0, subResult + " " + THOUSAND_POWER_MAP.get(index) + " ");
+                    } else {
+                        if (index > 0) {
+                            result = new StringBuilder(subResult + " " + THOUSAND_POWER_MAP.get(index));
+                        } else {
+                            result = new StringBuilder(subResult);
+                        }
+                    }
+                }
+            }
+
+            index++;
+        }
+
+        return result.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java b/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java
new file mode 100644
index 000000000000..49c43402aeca
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java
@@ -0,0 +1,15 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class IntegerToEnglishTest {
+
+    @Test
+    public void testIntegerToEnglish() {
+        assertEquals("Two Billion One Hundred Forty Seven Million Four Hundred Eighty Three Thousand Six Hundred Forty Seven", IntegerToEnglish.integerToEnglishWords(2147483647));
+        assertEquals("One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven", IntegerToEnglish.integerToEnglishWords(1234567));
+        assertEquals("Twelve Thousand Three Hundred Forty Five", IntegerToEnglish.integerToEnglishWords(12345));
+    }
+}

From 393337fa8e79e44f59c55a6504103d6b10c90088 Mon Sep 17 00:00:00 2001
From: Benjamin Burstein <98127047+bennybebo@users.noreply.github.com>
Date: Fri, 4 Oct 2024 13:18:51 -0400
Subject: [PATCH 0418/1338] Add Tests for HillCipher (#5562)

---
 .../com/thealgorithms/ciphers/HillCipher.java | 213 ++++++------------
 .../thealgorithms/ciphers/HillCipherTest.java |  36 +++
 2 files changed, 105 insertions(+), 144 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/ciphers/HillCipherTest.java

diff --git a/src/main/java/com/thealgorithms/ciphers/HillCipher.java b/src/main/java/com/thealgorithms/ciphers/HillCipher.java
index 780009c2f1d6..01b1aeb8bc6c 100644
--- a/src/main/java/com/thealgorithms/ciphers/HillCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/HillCipher.java
@@ -1,178 +1,103 @@
 package com.thealgorithms.ciphers;
 
-import java.util.Scanner;
+public class HillCipher {
 
-/*
- * Java Implementation of Hill Cipher
- * Hill cipher is a polyalphabetic substitution cipher. Each letter is represented by a number
- * belonging to the set Z26 where A=0 , B=1, ..... Z=25. To encrypt a message, each block of n
- * letters (since matrix size is n x n) is multiplied by an invertible n × n matrix, against
- * modulus 26. To decrypt the message, each block is multiplied by the inverse of the matrix used
- * for encryption. The cipher key and plaintext/ciphertext are user inputs.
- * @author Ojasva Jain
- */
-public final class HillCipher {
-    private HillCipher() {
-    }
-
-    static Scanner userInput = new Scanner(System.in);
-
-    /* Following function encrypts the message
-     */
-    static void encrypt(String message) {
-        message = message.toUpperCase();
-        // Get key matrix
-        System.out.println("Enter key matrix size");
-        int matrixSize = userInput.nextInt();
-        System.out.println("Enter Key/encryptionKey matrix ");
-        int[][] keyMatrix = new int[matrixSize][matrixSize];
-        for (int i = 0; i < matrixSize; i++) {
-            for (int j = 0; j < matrixSize; j++) {
-                keyMatrix[i][j] = userInput.nextInt();
-            }
-        }
-        // check if det = 0
+    // Encrypts the message using the key matrix
+    public String encrypt(String message, int[][] keyMatrix) {
+        message = message.toUpperCase().replaceAll("[^A-Z]", "");
+        int matrixSize = keyMatrix.length;
         validateDeterminant(keyMatrix, matrixSize);
 
-        int[][] messageVector = new int[matrixSize][1];
-        String cipherText = "";
-        int[][] cipherMatrix = new int[matrixSize][1];
-        int j = 0;
-        while (j < message.length()) {
+        StringBuilder cipherText = new StringBuilder();
+        int[] messageVector = new int[matrixSize];
+        int[] cipherVector = new int[matrixSize];
+        int index = 0;
+
+        while (index < message.length()) {
             for (int i = 0; i < matrixSize; i++) {
-                if (j >= message.length()) {
-                    messageVector[i][0] = 23;
+                if (index < message.length()) {
+                    messageVector[i] = message.charAt(index++) - 'A';
                 } else {
-                    messageVector[i][0] = (message.charAt(j)) % 65;
+                    messageVector[i] = 'X' - 'A'; // Padding with 'X' if needed
                 }
-                System.out.println(messageVector[i][0]);
-                j++;
             }
-            int x;
-            int i;
-            for (i = 0; i < matrixSize; i++) {
-                cipherMatrix[i][0] = 0;
 
-                for (x = 0; x < matrixSize; x++) {
-                    cipherMatrix[i][0] += keyMatrix[i][x] * messageVector[x][0];
+            for (int i = 0; i < matrixSize; i++) {
+                cipherVector[i] = 0;
+                for (int j = 0; j < matrixSize; j++) {
+                    cipherVector[i] += keyMatrix[i][j] * messageVector[j];
                 }
-                System.out.println(cipherMatrix[i][0]);
-                cipherMatrix[i][0] = cipherMatrix[i][0] % 26;
-            }
-            for (i = 0; i < matrixSize; i++) {
-                cipherText += (char) (cipherMatrix[i][0] + 65);
+                cipherVector[i] = cipherVector[i] % 26;
+                cipherText.append((char) (cipherVector[i] + 'A'));
             }
         }
-        System.out.println("Ciphertext: " + cipherText);
+
+        return cipherText.toString();
     }
 
-    // Following function decrypts a message
-    static void decrypt(String message) {
-        message = message.toUpperCase();
-        // Get key matrix
-        System.out.println("Enter key matrix size");
-        int n = userInput.nextInt();
-        System.out.println("Enter inverseKey/decryptionKey matrix ");
-        int[][] keyMatrix = new int[n][n];
-        for (int i = 0; i < n; i++) {
-            for (int j = 0; j < n; j++) {
-                keyMatrix[i][j] = userInput.nextInt();
-            }
-        }
-        // check if det = 0
-        validateDeterminant(keyMatrix, n);
+    // Decrypts the message using the inverse key matrix
+    public String decrypt(String message, int[][] inverseKeyMatrix) {
+        message = message.toUpperCase().replaceAll("[^A-Z]", "");
+        int matrixSize = inverseKeyMatrix.length;
+        validateDeterminant(inverseKeyMatrix, matrixSize);
+
+        StringBuilder plainText = new StringBuilder();
+        int[] messageVector = new int[matrixSize];
+        int[] plainVector = new int[matrixSize];
+        int index = 0;
 
-        // solving for the required plaintext message
-        int[][] messageVector = new int[n][1];
-        String plainText = "";
-        int[][] plainMatrix = new int[n][1];
-        int j = 0;
-        while (j < message.length()) {
-            for (int i = 0; i < n; i++) {
-                if (j >= message.length()) {
-                    messageVector[i][0] = 23;
+        while (index < message.length()) {
+            for (int i = 0; i < matrixSize; i++) {
+                if (index < message.length()) {
+                    messageVector[i] = message.charAt(index++) - 'A';
                 } else {
-                    messageVector[i][0] = (message.charAt(j)) % 65;
+                    messageVector[i] = 'X' - 'A'; // Padding with 'X' if needed
                 }
-                System.out.println(messageVector[i][0]);
-                j++;
             }
-            int x;
-            int i;
-            for (i = 0; i < n; i++) {
-                plainMatrix[i][0] = 0;
 
-                for (x = 0; x < n; x++) {
-                    plainMatrix[i][0] += keyMatrix[i][x] * messageVector[x][0];
+            for (int i = 0; i < matrixSize; i++) {
+                plainVector[i] = 0;
+                for (int j = 0; j < matrixSize; j++) {
+                    plainVector[i] += inverseKeyMatrix[i][j] * messageVector[j];
                 }
-
-                plainMatrix[i][0] = plainMatrix[i][0] % 26;
-            }
-            for (i = 0; i < n; i++) {
-                plainText += (char) (plainMatrix[i][0] + 65);
+                plainVector[i] = plainVector[i] % 26;
+                plainText.append((char) (plainVector[i] + 'A'));
             }
         }
-        System.out.println("Plaintext: " + plainText);
+
+        return plainText.toString();
     }
 
-    // Determinant calculator
-    public static int determinant(int[][] a, int n) {
-        int det = 0;
-        int sign = 1;
-        int p = 0;
-        int q = 0;
+    // Validates that the determinant of the key matrix is not zero modulo 26
+    private void validateDeterminant(int[][] keyMatrix, int n) {
+        int det = determinant(keyMatrix, n) % 26;
+        if (det == 0) {
+            throw new IllegalArgumentException("Invalid key matrix. Determinant is zero modulo 26.");
+        }
+    }
 
+    // Computes the determinant of a matrix recursively
+    private int determinant(int[][] matrix, int n) {
+        int det = 0;
         if (n == 1) {
-            det = a[0][0];
-        } else {
-            int[][] b = new int[n - 1][n - 1];
-            for (int x = 0; x < n; x++) {
-                p = 0;
-                q = 0;
-                for (int i = 1; i < n; i++) {
-                    for (int j = 0; j < n; j++) {
-                        if (j != x) {
-                            b[p][q++] = a[i][j];
-                            if (q % (n - 1) == 0) {
-                                p++;
-                                q = 0;
-                            }
-                        }
+            return matrix[0][0];
+        }
+        int sign = 1;
+        int[][] subMatrix = new int[n - 1][n - 1];
+        for (int x = 0; x < n; x++) {
+            int subI = 0;
+            for (int i = 1; i < n; i++) {
+                int subJ = 0;
+                for (int j = 0; j < n; j++) {
+                    if (j != x) {
+                        subMatrix[subI][subJ++] = matrix[i][j];
                     }
                 }
-                det = det + a[0][x] * determinant(b, n - 1) * sign;
-                sign = -sign;
+                subI++;
             }
+            det += sign * matrix[0][x] * determinant(subMatrix, n - 1);
+            sign = -sign;
         }
         return det;
     }
-
-    // Function to implement Hill Cipher
-    static void hillCipher(String message) {
-        System.out.println("What do you want to process from the message?");
-        System.out.println("Press 1: To Encrypt");
-        System.out.println("Press 2: To Decrypt");
-        short sc = userInput.nextShort();
-        if (sc == 1) {
-            encrypt(message);
-        } else if (sc == 2) {
-            decrypt(message);
-        } else {
-            System.out.println("Invalid input, program terminated.");
-        }
-    }
-
-    static void validateDeterminant(int[][] keyMatrix, int n) {
-        if (determinant(keyMatrix, n) % 26 == 0) {
-            System.out.println("Invalid key, as determinant = 0. Program Terminated");
-        }
-    }
-
-    // Driver code
-    public static void main(String[] args) {
-        // Get the message to be encrypted
-        System.out.println("Enter message");
-        String message = userInput.nextLine();
-        hillCipher(message);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/ciphers/HillCipherTest.java b/src/test/java/com/thealgorithms/ciphers/HillCipherTest.java
new file mode 100644
index 000000000000..8121b6177aa9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/HillCipherTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class HillCipherTest {
+
+    HillCipher hillCipher = new HillCipher();
+
+    @Test
+    void hillCipherEncryptTest() {
+        // given
+        String message = "ACT"; // Plaintext message
+        int[][] keyMatrix = {{6, 24, 1}, {13, 16, 10}, {20, 17, 15}}; // Encryption key matrix
+
+        // when
+        String cipherText = hillCipher.encrypt(message, keyMatrix);
+
+        // then
+        assertEquals("POH", cipherText);
+    }
+
+    @Test
+    void hillCipherDecryptTest() {
+        // given
+        String cipherText = "POH"; // Ciphertext message
+        int[][] inverseKeyMatrix = {{8, 5, 10}, {21, 8, 21}, {21, 12, 8}}; // Decryption (inverse key) matrix
+
+        // when
+        String plainText = hillCipher.decrypt(cipherText, inverseKeyMatrix);
+
+        // then
+        assertEquals("ACT", plainText);
+    }
+}

From 042d458d34043d54ae9331864a4c227b62a70355 Mon Sep 17 00:00:00 2001
From: B Karthik <115967163+BKarthik7@users.noreply.github.com>
Date: Fri, 4 Oct 2024 23:17:50 +0530
Subject: [PATCH 0419/1338] fix: change location of others to correct places
 (#5559)

---
 DIRECTORY.md                                  | 22 +++++++++----------
 .../CountSetBits.java                         |  2 +-
 .../others/ArrayRightRotation.java            | 21 ++++++++++++++++++
 .../{others => strings}/CountChar.java        |  2 +-
 .../{others => strings}/CountWords.java       |  2 +-
 .../ReturnSubsequence.java                    |  2 +-
 .../StringMatchFiniteAutomata.java            |  2 +-
 .../CountSetBitsTest.java                     |  2 +-
 .../{others => strings}/CountCharTest.java    |  2 +-
 .../{others => strings}/CountWordsTest.java   |  2 +-
 .../ReturnSubsequenceTest.java                |  2 +-
 .../StringMatchFiniteAutomataTest.java        |  2 +-
 12 files changed, 42 insertions(+), 21 deletions(-)
 rename src/main/java/com/thealgorithms/{others => bitmanipulation}/CountSetBits.java (97%)
 rename src/{test => main}/java/com/thealgorithms/others/ArrayRightRotation.java (52%)
 rename src/main/java/com/thealgorithms/{others => strings}/CountChar.java (93%)
 rename src/main/java/com/thealgorithms/{others => strings}/CountWords.java (97%)
 rename src/main/java/com/thealgorithms/{others => strings}/ReturnSubsequence.java (97%)
 rename src/main/java/com/thealgorithms/{others => strings}/StringMatchFiniteAutomata.java (99%)
 rename src/test/java/com/thealgorithms/{others => bitmanipulation}/CountSetBitsTest.java (90%)
 rename src/test/java/com/thealgorithms/{others => strings}/CountCharTest.java (96%)
 rename src/test/java/com/thealgorithms/{others => strings}/CountWordsTest.java (97%)
 rename src/test/java/com/thealgorithms/{others => strings}/ReturnSubsequenceTest.java (96%)
 rename src/test/java/com/thealgorithms/{others => strings}/StringMatchFiniteAutomataTest.java (97%)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0b282d8fb747..c272d3865b58 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -22,6 +22,7 @@
             * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
           * bitmanipulation
             * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
+            * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountSetBits.java)
             * [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
             * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
             * [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
@@ -409,6 +410,7 @@
             * [WordBoggle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/WordBoggle.java)
           * others
             * [ArrayLeftRotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java)
+            * [ArrayRightRotation](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotation.java)
             * [BankersAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/BankersAlgorithm.java)
             * [BFPRT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/BFPRT.java)
             * [BoyerMoore](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/BoyerMoore.java)
@@ -416,9 +418,6 @@
             * cn
               * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/cn/HammingDistance.java)
             * [Conway](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Conway.java)
-            * [CountChar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountChar.java)
-            * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountSetBits.java)
-            * [CountWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountWords.java)
             * [CRC16](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CRC16.java)
             * [CRC32](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CRC32.java)
             * [CRCAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CRCAlgorithm.java)
@@ -447,11 +446,9 @@
             * [PrintAMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java)
             * [QueueUsingTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java)
             * [RemoveDuplicateFromString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java)
-            * [ReturnSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReturnSubsequence.java)
             * [ReverseStackUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
             * [RotateMatrixBy90Degrees](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java)
             * [SkylineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SkylineProblem.java)
-            * [StringMatchFiniteAutomata](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java)
             * [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Sudoku.java)
             * [TowerOfHanoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TowerOfHanoi.java)
             * [TwoPointers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TwoPointers.java)
@@ -562,6 +559,8 @@
             * [CharactersSame](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CharactersSame.java)
             * [CheckAnagrams](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CheckAnagrams.java)
             * [CheckVowels](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CheckVowels.java)
+            * [CountChar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountChar.java)
+            * [CountWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountWords.java)
             * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/HammingDistance.java)
             * [HorspoolSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/HorspoolSearch.java)
             * [Isomorphic](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Isomorphic.java)
@@ -576,11 +575,13 @@
             * [Pangram](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Pangram.java)
             * [PermuteString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/PermuteString.java)
             * [RabinKarp](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/RabinKarp.java)
+            * [ReturnSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReturnSubsequence.java)
             * [ReverseString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseString.java)
             * [ReverseStringRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java)
             * [ReverseWordsInString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java)
             * [Rotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Rotation.java)
             * [StringCompression](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/StringCompression.java)
+            * [StringMatchFiniteAutomata](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java)
             * [Upper](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Upper.java)
             * [ValidParentheses](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ValidParentheses.java)
             * [WordLadder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/WordLadder.java)
@@ -605,6 +606,7 @@
             * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
           * bitmanipulation
             * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
+            * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountSetBitsTest.java)
             * [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
             * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
             * [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
@@ -875,7 +877,6 @@
             * [TwoSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
           * others
             * [ArrayLeftRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java)
-            * [ArrayRightRotation](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotation.java)
             * [ArrayRightRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java)
             * [BestFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BestFitCPUTest.java)
             * [BFPRTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BFPRTTest.java)
@@ -883,10 +884,7 @@
             * cn
               * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java)
             * [ConwayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ConwayTest.java)
-            * [CountCharTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountCharTest.java)
             * [CountFriendsPairingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountFriendsPairingTest.java)
-            * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountSetBitsTest.java)
-            * [CountWordsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountWordsTest.java)
             * [CRC16Test](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CRC16Test.java)
             * [CRCAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java)
             * [FirstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/FirstFitCPUTest.java)
@@ -901,9 +899,7 @@
             * [PasswordGenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/PasswordGenTest.java)
             * [QueueUsingTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java)
             * [RemoveDuplicateFromStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java)
-            * [ReturnSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java)
             * [ReverseStackUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
-            * [StringMatchFiniteAutomataTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java)
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
@@ -995,6 +991,8 @@
             * [CharacterSameTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CharacterSameTest.java)
             * [CheckAnagramsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CheckAnagramsTest.java)
             * [CheckVowelsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java)
+            * [CountCharTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountCharTest.java)
+            * [CountWordsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountWordsTest.java)
             * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HammingDistanceTest.java)
             * [HorspoolSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java)
             * [IsomorphicTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/IsomorphicTest.java)
@@ -1007,11 +1005,13 @@
             * [PalindromeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PalindromeTest.java)
             * [PangramTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PangramTest.java)
             * [PermuteStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PermuteStringTest.java)
+            * [ReturnSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java)
             * [ReverseStringRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java)
             * [ReverseStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseStringTest.java)
             * [ReverseWordsInStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java)
             * [RotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/RotationTest.java)
             * [StringCompressionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/StringCompressionTest.java)
+            * [StringMatchFiniteAutomataTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java)
             * [UpperTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/UpperTest.java)
             * [ValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java)
             * [WordLadderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/WordLadderTest.java)
diff --git a/src/main/java/com/thealgorithms/others/CountSetBits.java b/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java
similarity index 97%
rename from src/main/java/com/thealgorithms/others/CountSetBits.java
rename to src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java
index b26f745d4cd7..eb0886e30292 100644
--- a/src/main/java/com/thealgorithms/others/CountSetBits.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.bitmanipulation;
 
 public class CountSetBits {
 
diff --git a/src/test/java/com/thealgorithms/others/ArrayRightRotation.java b/src/main/java/com/thealgorithms/others/ArrayRightRotation.java
similarity index 52%
rename from src/test/java/com/thealgorithms/others/ArrayRightRotation.java
rename to src/main/java/com/thealgorithms/others/ArrayRightRotation.java
index 11e4f44500b1..125edadb6e73 100644
--- a/src/test/java/com/thealgorithms/others/ArrayRightRotation.java
+++ b/src/main/java/com/thealgorithms/others/ArrayRightRotation.java
@@ -1,8 +1,23 @@
 package com.thealgorithms.others;
 
+/**
+ * Provides a method to perform a right rotation on an array.
+ * A left rotation operation shifts each element of the array
+ * by a specified number of positions to the right.
+ *
+ * https://en.wikipedia.org/wiki/Right_rotation *
+ */
 public final class ArrayRightRotation {
     private ArrayRightRotation() {
     }
+
+    /**
+     * Performs a right rotation on the given array by the specified number of positions.
+     *
+     * @param arr the array to be rotated
+     * @param k the number of positions to rotate the array to the left
+     * @return a new array containing the elements of the input array rotated to the left
+     */
     public static int[] rotateRight(int[] arr, int k) {
         if (arr == null || arr.length == 0 || k < 0) {
             throw new IllegalArgumentException("Invalid input");
@@ -18,6 +33,12 @@ public static int[] rotateRight(int[] arr, int k) {
         return arr;
     }
 
+    /**
+     * Performs reversing of a array
+     * @param arr the array to be reversed
+     * @param start starting position
+     * @param end ending position
+     */
     private static void reverseArray(int[] arr, int start, int end) {
         while (start < end) {
             int temp = arr[start];
diff --git a/src/main/java/com/thealgorithms/others/CountChar.java b/src/main/java/com/thealgorithms/strings/CountChar.java
similarity index 93%
rename from src/main/java/com/thealgorithms/others/CountChar.java
rename to src/main/java/com/thealgorithms/strings/CountChar.java
index 00cff6860216..348905445347 100644
--- a/src/main/java/com/thealgorithms/others/CountChar.java
+++ b/src/main/java/com/thealgorithms/strings/CountChar.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 public final class CountChar {
     private CountChar() {
diff --git a/src/main/java/com/thealgorithms/others/CountWords.java b/src/main/java/com/thealgorithms/strings/CountWords.java
similarity index 97%
rename from src/main/java/com/thealgorithms/others/CountWords.java
rename to src/main/java/com/thealgorithms/strings/CountWords.java
index 515c5d33fbf3..8ab0700f5586 100644
--- a/src/main/java/com/thealgorithms/others/CountWords.java
+++ b/src/main/java/com/thealgorithms/strings/CountWords.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 /**
  * @author Marcus
diff --git a/src/main/java/com/thealgorithms/others/ReturnSubsequence.java b/src/main/java/com/thealgorithms/strings/ReturnSubsequence.java
similarity index 97%
rename from src/main/java/com/thealgorithms/others/ReturnSubsequence.java
rename to src/main/java/com/thealgorithms/strings/ReturnSubsequence.java
index 7ef660ce6579..afa8c5f98678 100644
--- a/src/main/java/com/thealgorithms/others/ReturnSubsequence.java
+++ b/src/main/java/com/thealgorithms/strings/ReturnSubsequence.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 /**
  * Class for generating all subsequences of a given string.
diff --git a/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java b/src/main/java/com/thealgorithms/strings/StringMatchFiniteAutomata.java
similarity index 99%
rename from src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
rename to src/main/java/com/thealgorithms/strings/StringMatchFiniteAutomata.java
index 561845f41a07..719898a1fd74 100644
--- a/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java
+++ b/src/main/java/com/thealgorithms/strings/StringMatchFiniteAutomata.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 import java.util.Set;
 import java.util.TreeSet;
diff --git a/src/test/java/com/thealgorithms/others/CountSetBitsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java
similarity index 90%
rename from src/test/java/com/thealgorithms/others/CountSetBitsTest.java
rename to src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java
index ab34c6ba7876..412312109bec 100644
--- a/src/test/java/com/thealgorithms/others/CountSetBitsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.bitmanipulation;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
diff --git a/src/test/java/com/thealgorithms/others/CountCharTest.java b/src/test/java/com/thealgorithms/strings/CountCharTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/others/CountCharTest.java
rename to src/test/java/com/thealgorithms/strings/CountCharTest.java
index 2b87d3806002..c84f2d01c2c5 100644
--- a/src/test/java/com/thealgorithms/others/CountCharTest.java
+++ b/src/test/java/com/thealgorithms/strings/CountCharTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
diff --git a/src/test/java/com/thealgorithms/others/CountWordsTest.java b/src/test/java/com/thealgorithms/strings/CountWordsTest.java
similarity index 97%
rename from src/test/java/com/thealgorithms/others/CountWordsTest.java
rename to src/test/java/com/thealgorithms/strings/CountWordsTest.java
index 17bb3aa692e7..a8aca1ae6092 100644
--- a/src/test/java/com/thealgorithms/others/CountWordsTest.java
+++ b/src/test/java/com/thealgorithms/strings/CountWordsTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
diff --git a/src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java b/src/test/java/com/thealgorithms/strings/ReturnSubsequenceTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java
rename to src/test/java/com/thealgorithms/strings/ReturnSubsequenceTest.java
index 0ae30c48c2a6..d4e1248d05ad 100644
--- a/src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReturnSubsequenceTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
diff --git a/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java b/src/test/java/com/thealgorithms/strings/StringMatchFiniteAutomataTest.java
similarity index 97%
rename from src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java
rename to src/test/java/com/thealgorithms/strings/StringMatchFiniteAutomataTest.java
index 6e1947b76a38..be460c7c4d91 100644
--- a/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java
+++ b/src/test/java/com/thealgorithms/strings/StringMatchFiniteAutomataTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 

From 02ed610eb64df6a11b9e61e4c81c645b5a643f22 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 5 Oct 2024 00:15:33 +0200
Subject: [PATCH 0420/1338] Chore(deps-dev): bump
 org.junit.jupiter:junit-jupiter-api from 5.11.1 to 5.11.2 (#5570)

Chore(deps-dev): bump org.junit.jupiter:junit-jupiter-api

Bumps [org.junit.jupiter:junit-jupiter-api](https://github.com/junit-team/junit5) from 5.11.1 to 5.11.2.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.1...r5.11.2)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter-api
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 882575fc654e..65e18fb880a9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -44,7 +44,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>5.11.1</version>
+            <version>5.11.2</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From e7c855bac23187f83f59ec6e71a5e7b12de1c9b8 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 4 Oct 2024 22:18:23 +0000
Subject: [PATCH 0421/1338] Chore(deps-dev): bump
 org.junit.jupiter:junit-jupiter from 5.11.1 to 5.11.2 (#5572)

Chore(deps-dev): bump org.junit.jupiter:junit-jupiter

Bumps [org.junit.jupiter:junit-jupiter](https://github.com/junit-team/junit5) from 5.11.1 to 5.11.2.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.1...r5.11.2)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 65e18fb880a9..0520a2358ba4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.11.1</version>
+            <version>5.11.2</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 87871efcdbbcca3a86ac5c2a4e9647b6f8267cf5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 4 Oct 2024 22:21:13 +0000
Subject: [PATCH 0422/1338] Chore(deps): bump org.junit:junit-bom from 5.11.1
 to 5.11.2 (#5571)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.11.1 to 5.11.2.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.1...r5.11.2)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 0520a2358ba4..ab12e8ec4082 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.11.1</version>
+                <version>5.11.2</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From ce345956288d2d304ff07f30e154c33832f651eb Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 5 Oct 2024 15:17:52 +0530
Subject: [PATCH 0423/1338] Improve `TrieImp.java` comments & enhance
 readability (#5526)

---
 DIRECTORY.md                                  |  27 ++--
 .../datastructures/trees/TrieImp.java         | 130 +++++++++---------
 .../datastructures/trees/TrieImpTest.java     |  76 ++++++++++
 3 files changed, 156 insertions(+), 77 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/TrieImpTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index c272d3865b58..fbd3b01c6321 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -22,7 +22,7 @@
             * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
           * bitmanipulation
             * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
-            * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountSetBits.java)
+            * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
             * [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
             * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
             * [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
@@ -69,7 +69,7 @@
             * [HexaDecimalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java)
             * [HexaDecimalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java)
             * [HexToOct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexToOct.java)
-            * [IntegerToEnglish] (https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java)
+            * [IntegerToEnglish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java)
             * [IntegerToRoman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java)
             * [OctalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToBinary.java)
             * [OctalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java)
@@ -410,7 +410,7 @@
             * [WordBoggle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/WordBoggle.java)
           * others
             * [ArrayLeftRotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java)
-            * [ArrayRightRotation](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotation.java)
+            * [ArrayRightRotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ArrayRightRotation.java)
             * [BankersAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/BankersAlgorithm.java)
             * [BFPRT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/BFPRT.java)
             * [BoyerMoore](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/BoyerMoore.java)
@@ -559,8 +559,8 @@
             * [CharactersSame](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CharactersSame.java)
             * [CheckAnagrams](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CheckAnagrams.java)
             * [CheckVowels](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CheckVowels.java)
-            * [CountChar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountChar.java)
-            * [CountWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CountWords.java)
+            * [CountChar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CountChar.java)
+            * [CountWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CountWords.java)
             * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/HammingDistance.java)
             * [HorspoolSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/HorspoolSearch.java)
             * [Isomorphic](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Isomorphic.java)
@@ -575,13 +575,13 @@
             * [Pangram](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Pangram.java)
             * [PermuteString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/PermuteString.java)
             * [RabinKarp](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/RabinKarp.java)
-            * [ReturnSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReturnSubsequence.java)
+            * [ReturnSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReturnSubsequence.java)
             * [ReverseString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseString.java)
             * [ReverseStringRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java)
             * [ReverseWordsInString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java)
             * [Rotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Rotation.java)
             * [StringCompression](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/StringCompression.java)
-            * [StringMatchFiniteAutomata](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java)
+            * [StringMatchFiniteAutomata](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/StringMatchFiniteAutomata.java)
             * [Upper](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Upper.java)
             * [ValidParentheses](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ValidParentheses.java)
             * [WordLadder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/WordLadder.java)
@@ -606,7 +606,7 @@
             * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
           * bitmanipulation
             * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
-            * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountSetBitsTest.java)
+            * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
             * [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
             * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
             * [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
@@ -621,6 +621,7 @@
             * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
             * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
             * [DESTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DESTest.java)
+            * [HillCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/HillCipherTest.java)
             * [PlayfairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java)
             * [PolybiusTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
             * [RSATest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RSATest.java)
@@ -639,6 +640,7 @@
             * [HexaDecimalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java)
             * [HexaDecimalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexaDecimalToDecimalTest.java)
             * [HexToOctTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexToOctTest.java)
+            * [IntegerToEnglishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java)
             * [IntegerToRomanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java)
             * [OctalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java)
             * [OctalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java)
@@ -727,6 +729,7 @@
               * [SameTreesCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SameTreesCheckTest.java)
               * [SplayTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java)
               * [TreeTestUtils](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java)
+              * [TrieImpTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TrieImpTest.java)
               * [VerticalOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversalTest.java)
               * [ZigzagTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/ZigzagTraversalTest.java)
           * divideandconquer
@@ -991,8 +994,8 @@
             * [CharacterSameTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CharacterSameTest.java)
             * [CheckAnagramsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CheckAnagramsTest.java)
             * [CheckVowelsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java)
-            * [CountCharTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountCharTest.java)
-            * [CountWordsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountWordsTest.java)
+            * [CountCharTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CountCharTest.java)
+            * [CountWordsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CountWordsTest.java)
             * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HammingDistanceTest.java)
             * [HorspoolSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java)
             * [IsomorphicTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/IsomorphicTest.java)
@@ -1005,13 +1008,13 @@
             * [PalindromeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PalindromeTest.java)
             * [PangramTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PangramTest.java)
             * [PermuteStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PermuteStringTest.java)
-            * [ReturnSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java)
+            * [ReturnSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReturnSubsequenceTest.java)
             * [ReverseStringRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java)
             * [ReverseStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseStringTest.java)
             * [ReverseWordsInStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java)
             * [RotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/RotationTest.java)
             * [StringCompressionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/StringCompressionTest.java)
-            * [StringMatchFiniteAutomataTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java)
+            * [StringMatchFiniteAutomataTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/StringMatchFiniteAutomataTest.java)
             * [UpperTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/UpperTest.java)
             * [ValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java)
             * [WordLadderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/WordLadderTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java b/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java
index d166653ff1b4..a43a454146cb 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java
@@ -1,19 +1,35 @@
 package com.thealgorithms.datastructures.trees;
 
-import java.util.Scanner;
-
 /**
- * Trie Data structure implementation without any libraries
+ * Trie Data structure implementation without any libraries.
+ * <p>
+ * The Trie (also known as a prefix tree) is a special tree-like data structure
+ * that is used to store a dynamic set or associative array where the keys are
+ * usually strings. It is highly efficient for prefix-based searches.
+ * <p>
+ * This implementation supports basic Trie operations like insertion, search,
+ * and deletion.
+ * <p>
+ * Each node of the Trie represents a character and has child nodes for each
+ * possible character.
  *
  * @author <a href="https://github.com/dheeraj92">Dheeraj Kumar Barnwal</a>
  */
 public class TrieImp {
 
+    /**
+     * Represents a Trie Node that stores a character and pointers to its children.
+     * Each node has an array of 26 children (one for each letter from 'a' to 'z').
+     */
     public class TrieNode {
 
         TrieNode[] child;
         boolean end;
 
+        /**
+         * Constructor to initialize a TrieNode with an empty child array
+         * and set end to false.
+         */
         public TrieNode() {
             child = new TrieNode[26];
             end = false;
@@ -22,10 +38,22 @@ public TrieNode() {
 
     private final TrieNode root;
 
+    /**
+     * Constructor to initialize the Trie.
+     * The root node is created but doesn't represent any character.
+     */
     public TrieImp() {
         root = new TrieNode();
     }
 
+    /**
+     * Inserts a word into the Trie.
+     * <p>
+     * The method traverses the Trie from the root, character by character, and adds
+     * nodes if necessary. It marks the last node of the word as an end node.
+     *
+     * @param word The word to be inserted into the Trie.
+     */
     public void insert(String word) {
         TrieNode currentNode = root;
         for (int i = 0; i < word.length(); i++) {
@@ -39,6 +67,16 @@ public void insert(String word) {
         currentNode.end = true;
     }
 
+    /**
+     * Searches for a word in the Trie.
+     * <p>
+     * This method traverses the Trie based on the input word and checks whether
+     * the word exists. It returns true if the word is found and its end flag is
+     * true.
+     *
+     * @param word The word to search in the Trie.
+     * @return true if the word exists in the Trie, false otherwise.
+     */
     public boolean search(String word) {
         TrieNode currentNode = root;
         for (int i = 0; i < word.length(); i++) {
@@ -52,6 +90,17 @@ public boolean search(String word) {
         return currentNode.end;
     }
 
+    /**
+     * Deletes a word from the Trie.
+     * <p>
+     * The method traverses the Trie to find the word and marks its end flag as
+     * false.
+     * It returns true if the word was successfully deleted, false if the word
+     * wasn't found.
+     *
+     * @param word The word to be deleted from the Trie.
+     * @return true if the word was found and deleted, false if it was not found.
+     */
     public boolean delete(String word) {
         TrieNode currentNode = root;
         for (int i = 0; i < word.length(); i++) {
@@ -69,75 +118,26 @@ public boolean delete(String word) {
         return false;
     }
 
+    /**
+     * Helper method to print a string to the console.
+     *
+     * @param print The string to be printed.
+     */
     public static void sop(String print) {
         System.out.println(print);
     }
 
     /**
-     * Regex to check if word contains only a-z character
+     * Validates if a given word contains only lowercase alphabetic characters
+     * (a-z).
+     * <p>
+     * The method uses a regular expression to check if the word matches the pattern
+     * of only lowercase letters.
+     *
+     * @param word The word to be validated.
+     * @return true if the word is valid (only a-z), false otherwise.
      */
     public static boolean isValid(String word) {
         return word.matches("^[a-z]+$");
     }
-
-    public static void main(String[] args) {
-        TrieImp obj = new TrieImp();
-        String word;
-        @SuppressWarnings("resource") Scanner scan = new Scanner(System.in);
-        sop("string should contain only a-z character for all operation");
-        while (true) {
-            sop("1. Insert\n2. Search\n3. Delete\n4. Quit");
-            try {
-                int t = scan.nextInt();
-                switch (t) {
-                case 1:
-                    word = scan.next();
-                    if (isValid(word)) {
-                        obj.insert(word);
-                    } else {
-                        sop("Invalid string: allowed only a-z");
-                    }
-                    break;
-                case 2:
-                    word = scan.next();
-                    boolean resS = false;
-                    if (isValid(word)) {
-                        resS = obj.search(word);
-                    } else {
-                        sop("Invalid string: allowed only a-z");
-                    }
-                    if (resS) {
-                        sop("word found");
-                    } else {
-                        sop("word not found");
-                    }
-                    break;
-                case 3:
-                    word = scan.next();
-                    boolean resD = false;
-                    if (isValid(word)) {
-                        resD = obj.delete(word);
-                    } else {
-                        sop("Invalid string: allowed only a-z");
-                    }
-                    if (resD) {
-                        sop("word got deleted successfully");
-                    } else {
-                        sop("word not found");
-                    }
-                    break;
-                case 4:
-                    sop("Quit successfully");
-                    System.exit(1);
-                    break;
-                default:
-                    sop("Input int from 1-4");
-                    break;
-                }
-            } catch (Exception e) {
-                String badInput = scan.next();
-                sop("This is bad input: " + badInput);
-            }
-        }
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/TrieImpTest.java b/src/test/java/com/thealgorithms/datastructures/trees/TrieImpTest.java
new file mode 100644
index 000000000000..600fdef0a718
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/TrieImpTest.java
@@ -0,0 +1,76 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class TrieImpTest {
+    private TrieImp trie;
+
+    @BeforeEach
+    public void setUp() {
+        trie = new TrieImp();
+    }
+
+    @Test
+    public void testInsertAndSearchBasic() {
+        String word = "hello";
+        trie.insert(word);
+        assertTrue(trie.search(word), "Search should return true for an inserted word.");
+    }
+
+    @Test
+    public void testSearchNonExistentWord() {
+        String word = "world";
+        assertFalse(trie.search(word), "Search should return false for a non-existent word.");
+    }
+
+    @Test
+    public void testInsertAndSearchMultipleWords() {
+        String word1 = "cat";
+        String word2 = "car";
+        trie.insert(word1);
+        trie.insert(word2);
+
+        assertTrue(trie.search(word1), "Search should return true for an inserted word.");
+        assertTrue(trie.search(word2), "Search should return true for another inserted word.");
+        assertFalse(trie.search("dog"), "Search should return false for a word not in the Trie.");
+    }
+
+    @Test
+    public void testDeleteExistingWord() {
+        String word = "remove";
+        trie.insert(word);
+        assertTrue(trie.delete(word), "Delete should return true for an existing word.");
+        assertFalse(trie.search(word), "Search should return false after deletion.");
+    }
+
+    @Test
+    public void testDeleteNonExistentWord() {
+        String word = "nonexistent";
+        assertFalse(trie.delete(word), "Delete should return false for a non-existent word.");
+    }
+
+    @Test
+    public void testInsertAndSearchPrefix() {
+        String prefix = "pre";
+        String word = "prefix";
+        trie.insert(prefix);
+        trie.insert(word);
+
+        assertTrue(trie.search(prefix), "Search should return true for an inserted prefix.");
+        assertTrue(trie.search(word), "Search should return true for a word with the prefix.");
+        assertFalse(trie.search("pref"), "Search should return false for a prefix that is not a full word.");
+    }
+
+    @Test
+    public void testIsValidWord() {
+        assertTrue(TrieImp.isValid("validword"), "Word should be valid (only lowercase letters).");
+        assertFalse(TrieImp.isValid("InvalidWord"), "Word should be invalid (contains uppercase letters).");
+        assertFalse(TrieImp.isValid("123abc"), "Word should be invalid (contains numbers).");
+        assertFalse(TrieImp.isValid("hello!"), "Word should be invalid (contains special characters).");
+        assertFalse(TrieImp.isValid(""), "Empty string should be invalid.");
+    }
+}

From 339027388e20297396196d58b19b03b9322efb3f Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 5 Oct 2024 18:09:22 +0530
Subject: [PATCH 0424/1338] Improve comments in `SumOfSubset.java` (#5514)

---
 .../dynamicprogramming/SumOfSubset.java       | 27 ++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java b/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
index dd48008bd21e..e9c15c1b4f24 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java
@@ -1,9 +1,35 @@
 package com.thealgorithms.dynamicprogramming;
 
+/**
+ * A utility class that contains the Sum of Subset problem solution using
+ * recursion.
+ *
+ * The Sum of Subset problem determines whether a subset of elements from a
+ * given array sums up to a specific target value.
+ *
+ * Wikipedia: https://en.wikipedia.org/wiki/Subset_sum_problem
+ */
 public final class SumOfSubset {
+
     private SumOfSubset() {
     }
 
+    /**
+     * Determines if there exists a subset of elements in the array `arr` that
+     * adds up to the given `key` value using recursion.
+     *
+     * @param arr The array of integers.
+     * @param num The index of the current element being considered.
+     * @param key The target sum we are trying to achieve.
+     * @return true if a subset of `arr` adds up to `key`, false otherwise.
+     *
+     *         This is a recursive solution that checks for two possibilities at
+     *         each step:
+     *         1. Include the current element in the subset and check if the
+     *         remaining elements can sum up to the remaining target.
+     *         2. Exclude the current element and check if the remaining elements
+     *         can sum up to the target without this element.
+     */
     public static boolean subsetSum(int[] arr, int num, int key) {
         if (key == 0) {
             return true;
@@ -14,7 +40,6 @@ public static boolean subsetSum(int[] arr, int num, int key) {
 
         boolean include = subsetSum(arr, num - 1, key - arr[num]);
         boolean exclude = subsetSum(arr, num - 1, key);
-
         return include || exclude;
     }
 }

From f34fe4d8408ac35cef900cfae022ffadfc007ea3 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 5 Oct 2024 18:13:42 +0530
Subject: [PATCH 0425/1338] Enhance comments & improve readability in
 `LongestCommonSubsequence.java` (#5523)

---
 DIRECTORY.md                                  |  1 +
 .../LongestCommonSubsequence.java             | 67 +++++++++-----
 .../LongestCommonSubsequenceTest.java         | 89 +++++++++++++++++++
 3 files changed, 136 insertions(+), 21 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index fbd3b01c6321..1bad5d3b98a3 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -747,6 +747,7 @@
             * [LevenshteinDistanceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
             * [LongestAlternatingSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java)
             * [LongestArithmeticSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequenceTest.java)
+            * [LongestCommonSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java)
             * [LongestIncreasingSubsequenceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java)
             * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java)
             * [LongestValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java
index 2d1fa1d1153f..54837b5f4e71 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java
@@ -1,73 +1,98 @@
 package com.thealgorithms.dynamicprogramming;
 
+/**
+ * This class implements the Longest Common Subsequence (LCS) problem.
+ * The LCS of two sequences is the longest sequence that appears in both
+ * sequences
+ * in the same order, but not necessarily consecutively.
+ *
+ * This implementation uses dynamic programming to find the LCS of two strings.
+ */
 final class LongestCommonSubsequence {
+
     private LongestCommonSubsequence() {
     }
 
+    /**
+     * Returns the Longest Common Subsequence (LCS) of two given strings.
+     *
+     * @param str1 The first string.
+     * @param str2 The second string.
+     * @return The LCS of the two strings, or null if one of the strings is null.
+     */
     public static String getLCS(String str1, String str2) {
-        // At least one string is null
+        // If either string is null, return null as LCS can't be computed.
         if (str1 == null || str2 == null) {
             return null;
         }
-
-        // At least one string is empty
+        // If either string is empty, return an empty string as LCS.
         if (str1.length() == 0 || str2.length() == 0) {
             return "";
         }
 
+        // Convert the strings into arrays of characters
         String[] arr1 = str1.split("");
         String[] arr2 = str2.split("");
 
-        // lcsMatrix[i][j]  = LCS of first i elements of arr1 and first j characters of arr2
+        // lcsMatrix[i][j] = LCS(first i characters of str1, first j characters of str2)
         int[][] lcsMatrix = new int[arr1.length + 1][arr2.length + 1];
 
+        // Base Case: Fill the LCS matrix 0th row & 0th column with 0s
+        // as LCS of any string with an empty string is 0.
         for (int i = 0; i < arr1.length + 1; i++) {
             lcsMatrix[i][0] = 0;
         }
         for (int j = 1; j < arr2.length + 1; j++) {
             lcsMatrix[0][j] = 0;
         }
+
+        // Build the LCS matrix by comparing characters of str1 & str2
         for (int i = 1; i < arr1.length + 1; i++) {
             for (int j = 1; j < arr2.length + 1; j++) {
+                // If characters match, the LCS increases by 1
                 if (arr1[i - 1].equals(arr2[j - 1])) {
                     lcsMatrix[i][j] = lcsMatrix[i - 1][j - 1] + 1;
                 } else {
+                    // Otherwise, take the maximum of the left or above values
                     lcsMatrix[i][j] = Math.max(lcsMatrix[i - 1][j], lcsMatrix[i][j - 1]);
                 }
             }
         }
+
+        // Call helper function to reconstruct the LCS from the matrix
         return lcsString(str1, str2, lcsMatrix);
     }
 
+    /**
+     * Reconstructs the LCS string from the LCS matrix.
+     *
+     * @param str1      The first string.
+     * @param str2      The second string.
+     * @param lcsMatrix The matrix storing the lengths of LCSs
+     *                  of substrings of str1 and str2.
+     * @return The LCS string.
+     */
     public static String lcsString(String str1, String str2, int[][] lcsMatrix) {
-        StringBuilder lcs = new StringBuilder();
-        int i = str1.length();
-        int j = str2.length();
+        StringBuilder lcs = new StringBuilder(); // Hold the LCS characters.
+        int i = str1.length(); // Start from the end of str1.
+        int j = str2.length(); // Start from the end of str2.
+
+        // Trace back through the LCS matrix to reconstruct the LCS
         while (i > 0 && j > 0) {
+            // If characters match, add to the LCS and move diagonally in the matrix
             if (str1.charAt(i - 1) == str2.charAt(j - 1)) {
                 lcs.append(str1.charAt(i - 1));
                 i--;
                 j--;
             } else if (lcsMatrix[i - 1][j] > lcsMatrix[i][j - 1]) {
+                // If the value above is larger, move up
                 i--;
             } else {
+                // If the value to the left is larger, move left
                 j--;
             }
         }
-        return lcs.reverse().toString();
-    }
 
-    public static void main(String[] args) {
-        String str1 = "DSGSHSRGSRHTRD";
-        String str2 = "DATRGAGTSHS";
-        String lcs = getLCS(str1, str2);
-
-        // Print LCS
-        if (lcs != null) {
-            System.out.println("String 1: " + str1);
-            System.out.println("String 2: " + str2);
-            System.out.println("LCS: " + lcs);
-            System.out.println("LCS length: " + lcs.length());
-        }
+        return lcs.reverse().toString(); // LCS built in reverse, so reverse it back
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java
new file mode 100644
index 000000000000..40bbdff15ca6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java
@@ -0,0 +1,89 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class LongestCommonSubsequenceTest {
+
+    @Test
+    public void testLCSBasic() {
+        String str1 = "ABCBDAB";
+        String str2 = "BDCAB";
+        String expected = "BDAB"; // The longest common subsequence
+        String result = LongestCommonSubsequence.getLCS(str1, str2);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLCSIdenticalStrings() {
+        String str1 = "AGGTAB";
+        String str2 = "AGGTAB";
+        String expected = "AGGTAB"; // LCS is the same as the strings
+        String result = LongestCommonSubsequence.getLCS(str1, str2);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLCSNoCommonCharacters() {
+        String str1 = "ABC";
+        String str2 = "XYZ";
+        String expected = ""; // No common subsequence
+        String result = LongestCommonSubsequence.getLCS(str1, str2);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLCSWithEmptyString() {
+        String str1 = "";
+        String str2 = "XYZ";
+        String expected = ""; // LCS with an empty string should be empty
+        String result = LongestCommonSubsequence.getLCS(str1, str2);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLCSWithBothEmptyStrings() {
+        String str1 = "";
+        String str2 = "";
+        String expected = ""; // LCS with both strings empty should be empty
+        String result = LongestCommonSubsequence.getLCS(str1, str2);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLCSWithNullFirstString() {
+        String str1 = null;
+        String str2 = "XYZ";
+        String expected = null; // Should return null if first string is null
+        String result = LongestCommonSubsequence.getLCS(str1, str2);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLCSWithNullSecondString() {
+        String str1 = "ABC";
+        String str2 = null;
+        String expected = null; // Should return null if second string is null
+        String result = LongestCommonSubsequence.getLCS(str1, str2);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLCSWithNullBothStrings() {
+        String str1 = null;
+        String str2 = null;
+        String expected = null; // Should return null if both strings are null
+        String result = LongestCommonSubsequence.getLCS(str1, str2);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLCSWithLongerStringContainingCommonSubsequence() {
+        String str1 = "ABCDEF";
+        String str2 = "AEBDF";
+        String expected = "ABDF"; // Common subsequence is "ABDF"
+        String result = LongestCommonSubsequence.getLCS(str1, str2);
+        assertEquals(expected, result);
+    }
+}

From 07cb6c46a8d3b46d6b32c84e23da50ac8fecd30e Mon Sep 17 00:00:00 2001
From: Benjamin Burstein <98127047+bennybebo@users.noreply.github.com>
Date: Sun, 6 Oct 2024 01:37:56 -0400
Subject: [PATCH 0426/1338] Add autokey cipher (#5569)

---
 .../com/thealgorithms/ciphers/Autokey.java    | 55 +++++++++++++++++++
 .../thealgorithms/ciphers/AutokeyTest.java    | 36 ++++++++++++
 2 files changed, 91 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/Autokey.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/AutokeyTest.java

diff --git a/src/main/java/com/thealgorithms/ciphers/Autokey.java b/src/main/java/com/thealgorithms/ciphers/Autokey.java
new file mode 100644
index 000000000000..bb67f512accf
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/Autokey.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.ciphers;
+
+/**
+ * The Autokey Cipher is an interesting and historically significant encryption method,
+ * as it improves upon the classic Vigenère Cipher by using the plaintext itself to
+ * extend the key. This makes it harder to break using frequency analysis, as it
+ * doesn’t rely solely on a repeated key.
+ * https://en.wikipedia.org/wiki/Autokey_cipher
+ *
+ * @author bennybebo
+ */
+public class Autokey {
+
+    // Encrypts the plaintext using the Autokey cipher
+    public String encrypt(String plaintext, String keyword) {
+        plaintext = plaintext.toUpperCase().replaceAll("[^A-Z]", ""); // Sanitize input
+        keyword = keyword.toUpperCase();
+
+        StringBuilder extendedKey = new StringBuilder(keyword);
+        extendedKey.append(plaintext); // Extend key with plaintext
+
+        StringBuilder ciphertext = new StringBuilder();
+
+        for (int i = 0; i < plaintext.length(); i++) {
+            char plainChar = plaintext.charAt(i);
+            char keyChar = extendedKey.charAt(i);
+
+            int encryptedChar = (plainChar - 'A' + keyChar - 'A') % 26 + 'A';
+            ciphertext.append((char) encryptedChar);
+        }
+
+        return ciphertext.toString();
+    }
+
+    // Decrypts the ciphertext using the Autokey cipher
+    public String decrypt(String ciphertext, String keyword) {
+        ciphertext = ciphertext.toUpperCase().replaceAll("[^A-Z]", ""); // Sanitize input
+        keyword = keyword.toUpperCase();
+
+        StringBuilder plaintext = new StringBuilder();
+        StringBuilder extendedKey = new StringBuilder(keyword);
+
+        for (int i = 0; i < ciphertext.length(); i++) {
+            char cipherChar = ciphertext.charAt(i);
+            char keyChar = extendedKey.charAt(i);
+
+            int decryptedChar = (cipherChar - 'A' - (keyChar - 'A') + 26) % 26 + 'A';
+            plaintext.append((char) decryptedChar);
+
+            extendedKey.append((char) decryptedChar); // Extend key with each decrypted char
+        }
+
+        return plaintext.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java b/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java
new file mode 100644
index 000000000000..52ecff7cdeee
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class AutokeyCipherTest {
+
+    Autokey autokeyCipher = new Autokey();
+
+    @Test
+    void autokeyEncryptTest() {
+        // given
+        String plaintext = "MEET AT DAWN";
+        String keyword = "QUEEN";
+
+        // when
+        String cipherText = autokeyCipher.encrypt(plaintext, keyword);
+
+        // then
+        assertEquals("CYIXNFHEPN", cipherText);
+    }
+
+    @Test
+    void autokeyDecryptTest() {
+        // given
+        String ciphertext = "CYIX NF HEPN";
+        String keyword = "QUEEN";
+
+        // when
+        String plainText = autokeyCipher.decrypt(ciphertext, keyword);
+
+        // then
+        assertEquals("MEETATDAWN", plainText);
+    }
+}

From 4008e4967c52df999260757f4404ba85a7ab11c6 Mon Sep 17 00:00:00 2001
From: ShreeHarish <72642111+ShreeHarish@users.noreply.github.com>
Date: Sun, 6 Oct 2024 12:31:54 +0530
Subject: [PATCH 0427/1338] Add treap class (#5563)

---
 .../datastructures/trees/Treap.java           | 357 ++++++++++++++++++
 .../datastructures/trees/TreapTest.java       |  62 +++
 2 files changed, 419 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/trees/Treap.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/Treap.java b/src/main/java/com/thealgorithms/datastructures/trees/Treap.java
new file mode 100644
index 000000000000..1e5d551cc40b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/trees/Treap.java
@@ -0,0 +1,357 @@
+package com.thealgorithms.datastructures.trees;
+
+import java.util.Random;
+
+/**
+ * Treap -> Tree + Heap
+ * Also called as cartesian tree
+ *
+ * @see
+ * <a href = "https://cp-algorithms.com/data_structures/treap.html" />
+ */
+
+public class Treap {
+
+    public static class TreapNode {
+        /**
+         * TreapNode class defines the individual nodes in the Treap
+         *
+         * value -> holds the value of the node.
+         * Binary Search Tree is built based on value.
+         *
+         * priority -> holds the priority of the node.
+         * Heaps are maintained based on priority.
+         * It is randomly assigned
+         *
+         * size -> holds the size of the subtree with current node as root
+         *
+         * left -> holds the left subtree
+         * right -> holds the right subtree
+         */
+        public int value;
+        private int priority;
+        private int size;
+        public TreapNode left;
+        public TreapNode right;
+
+        public TreapNode(int valueParam, int priorityParam) {
+            value = valueParam;
+            priority = priorityParam;
+            size = 1;
+            left = null;
+            right = null;
+        }
+
+        /**
+         * updateSize -> updates the subtree size of the current node
+         */
+        private void updateSize() {
+            size = 1;
+            if (left != null) {
+                size += left.size;
+            }
+            if (right != null) {
+                size += right.size;
+            }
+        }
+    }
+
+    /**
+     * root -> holds the root node in the Treap
+     * random -> to generate random priority for the nodes in the Treap
+     */
+    private TreapNode root;
+    private Random random = new Random();
+
+    /**
+     * Constructors
+     *
+     * Treap() -> create an empty Treap
+     * Treap(int[] nodeValues) -> add the elements given in the array to the Treap
+     */
+    public Treap() {
+        root = null;
+    }
+
+    /**
+     * merges two Treaps left and right into a single Treap
+     *
+     * @param left left Treap
+     * @param right right Treap
+     * @return root of merged Treap
+     */
+    private TreapNode merge(TreapNode left, TreapNode right) {
+        if (left == null) {
+            return right;
+        }
+        if (right == null) {
+            return left;
+        }
+
+        if (left.priority > right.priority) {
+            left.right = merge(left.right, right);
+            left.updateSize();
+            return left;
+        } else {
+            right.left = merge(left, right.left);
+            right.updateSize();
+            return right;
+        }
+    }
+
+    /**
+     * split the Treap into two Treaps where left Treap has nodes <= key and right Treap has nodes > key
+     *
+     * @param node root node to be split
+     * @param key key to compare the nodes
+     * @return TreapNode array of size 2.
+     * TreapNode[0] contains the root of left Treap after split
+     * TreapNode[1] contains the root of right Treap after split
+     */
+    private TreapNode[] split(TreapNode node, int key) {
+        if (node == null) {
+            return new TreapNode[] {null, null};
+        }
+
+        TreapNode[] result;
+
+        if (node.value <= key) {
+            result = split(node.right, key);
+            node.right = result[0];
+            node.updateSize();
+            result[0] = node;
+        } else {
+            result = split(node.left, key);
+            node.left = result[1];
+            node.updateSize();
+            result[1] = node;
+        }
+
+        return result;
+    }
+
+    /**
+     * insert a node into the Treap
+     *
+     * @param value value to be inserted into the Treap
+     * @return root of the Treap where the value is inserted
+     */
+    public TreapNode insert(int value) {
+        if (root == null) {
+            root = new TreapNode(value, random.nextInt());
+            return root;
+        }
+
+        TreapNode[] splitted = split(root, value);
+
+        TreapNode node = new TreapNode(value, random.nextInt());
+
+        TreapNode tempMerged = merge(splitted[0], node);
+        tempMerged.updateSize();
+
+        TreapNode merged = merge(tempMerged, splitted[1]);
+        merged.updateSize();
+
+        root = merged;
+
+        return root;
+    }
+
+    /**
+     * delete a value from root if present
+     *
+     * @param value value to be deleted from the Treap
+     * @return root of the Treap where delete has been performed
+     */
+    public TreapNode delete(int value) {
+        root = deleteNode(root, value);
+        return root;
+    }
+
+    private TreapNode deleteNode(TreapNode root, int value) {
+        if (root == null) {
+            return null;
+        }
+
+        if (value < root.value) {
+            root.left = deleteNode(root.left, value);
+        } else if (value > root.value) {
+            root.right = deleteNode(root.right, value);
+        } else {
+            root = merge(root.left, root.right);
+        }
+
+        if (root != null) {
+            root.updateSize();
+        }
+        return root;
+    }
+
+    /**
+     * print inorder traversal of the Treap
+     */
+    public void inOrder() {
+        System.out.print("{");
+        printInorder(root);
+        System.out.print("}");
+    }
+
+    private void printInorder(TreapNode root) {
+        if (root == null) {
+            return;
+        }
+        printInorder(root.left);
+        System.out.print(root.value + ",");
+        printInorder(root.right);
+    }
+
+    /**
+     * print preOrder traversal of the Treap
+     */
+    public void preOrder() {
+        System.out.print("{");
+        printPreOrder(root);
+        System.out.print("}");
+    }
+
+    private void printPreOrder(TreapNode root) {
+        if (root == null) {
+            return;
+        }
+        System.out.print(root.value + ",");
+        printPreOrder(root.left);
+        printPreOrder(root.right);
+    }
+
+    /**
+     * print postOrder traversal of the Treap
+     */
+    public void postOrder() {
+        System.out.print("{");
+        printPostOrder(root);
+        System.out.print("}");
+    }
+
+    private void printPostOrder(TreapNode root) {
+        if (root == null) {
+            return;
+        }
+        printPostOrder(root.left);
+        printPostOrder(root.right);
+        System.out.print(root.value + ",");
+    }
+
+    /**
+     * Search a value in the Treap
+     *
+     * @param value value to be searched for
+     * @return node containing the value
+     * null if not found
+     */
+    public TreapNode search(int value) {
+        return searchVal(root, value);
+    }
+
+    private TreapNode searchVal(TreapNode root, int value) {
+        if (root == null) {
+            return null;
+        }
+
+        if (root.value == value) {
+            return root;
+        } else if (root.value < value) {
+            return searchVal(root.right, value);
+        } else {
+            return searchVal(root.left, value);
+        }
+    }
+
+    /**
+     * find the lowerBound of a value in the Treap
+     *
+     * @param value value for which lowerBound is to be found
+     * @return node which is the lowerBound of the value passed
+     */
+    public TreapNode lowerBound(int value) {
+        TreapNode lowerBoundNode = null;
+        TreapNode current = root;
+
+        while (current != null) {
+            if (current.value >= value) {
+                lowerBoundNode = current;
+                current = current.left;
+            } else {
+                current = current.right;
+            }
+        }
+
+        return lowerBoundNode;
+    }
+
+    /**
+     * find the upperBound of a value in the Treap
+     *
+     * @param value value for which upperBound is to be found
+     * @return node which is the upperBound of the value passed
+     */
+    public TreapNode upperBound(int value) {
+        TreapNode upperBoundNode = null;
+        TreapNode current = root;
+
+        while (current != null) {
+            if (current.value > value) {
+                upperBoundNode = current;
+                current = current.left;
+            } else {
+                current = current.right;
+            }
+        }
+
+        return upperBoundNode;
+    }
+
+    /**
+     * returns size of the Treap
+     */
+    public int size() {
+        if (root == null) {
+            return 0;
+        }
+        return root.size;
+    }
+
+    /**
+     * returns if Treap is empty
+     */
+    public boolean isEmpty() {
+        return root == null;
+    }
+
+    /**
+     * returns root node of the Treap
+     */
+    public TreapNode getRoot() {
+        return root;
+    }
+
+    /**
+     * returns left node of the TreapNode
+     */
+    public TreapNode getLeft(TreapNode node) {
+        return node.left;
+    }
+
+    /**
+     * returns the right node of the TreapNode
+     */
+    public TreapNode getRight(TreapNode node) {
+        return node.right;
+    }
+
+    /**
+     * prints the value, priority, size of the subtree of the TreapNode, left TreapNode and right TreapNode of the node
+     */
+    public String toString(TreapNode node) {
+        return "{value : " + node.value + ", priority : " + node.priority + ", subTreeSize = " + node.size + ", left = " + node.left + ", right = " + node.right + "}";
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java b/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java
new file mode 100644
index 000000000000..09ada594faca
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java
@@ -0,0 +1,62 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+import org.junit.jupiter.api.Test;
+
+public class TreapTest {
+
+    @Test
+    public void searchAndFound() {
+        Treap treap = new Treap();
+        treap.insert(5);
+        treap.insert(9);
+        treap.insert(6);
+        treap.insert(2);
+        treap.insert(3);
+        treap.insert(8);
+        treap.insert(1);
+        assertEquals(5, treap.search(5).value);
+    }
+
+    @Test
+    public void searchAndNotFound() {
+        Treap treap = new Treap();
+        treap.insert(5);
+        treap.insert(9);
+        treap.insert(6);
+        treap.insert(2);
+        treap.insert(3);
+        treap.insert(8);
+        treap.insert(1);
+        assertEquals(null, treap.search(4));
+    }
+
+    @Test
+    public void lowerBound() {
+        Treap treap = new Treap();
+        treap.insert(5);
+        treap.insert(9);
+        treap.insert(6);
+        treap.insert(2);
+        treap.insert(3);
+        treap.insert(8);
+        treap.insert(1);
+        assertEquals(5, treap.lowerBound(4).value);
+    }
+
+    @Test
+    public void size() {
+        Treap treap = new Treap();
+        treap.insert(5);
+        treap.insert(9);
+        treap.insert(6);
+        treap.insert(2);
+        treap.insert(3);
+        treap.insert(8);
+        treap.insert(1);
+        assertEquals(7, treap.size());
+        assertFalse(treap.isEmpty());
+    }
+}

From 1feceb7d11bb344c5022c5ae84a652370e737f30 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 6 Oct 2024 12:42:11 +0530
Subject: [PATCH 0428/1338] Add MLFQ Scheduler (#5575)

---
 DIRECTORY.md                                  |   6 +
 .../scheduling/MLFQScheduler.java             | 148 ++++++++++++++++++
 .../scheduling/MLFQSchedulerTest.java         |  46 ++++++
 3 files changed, 200 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 1bad5d3b98a3..d93dde3dffb6 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -42,6 +42,7 @@
             * [AES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AES.java)
             * [AESEncryption](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AESEncryption.java)
             * [AffineCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AffineCipher.java)
+            * [Autokey](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Autokey.java)
             * [Blowfish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Blowfish.java)
             * [Caesar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Caesar.java)
             * [ColumnarTranspositionCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java)
@@ -203,6 +204,7 @@
               * [SameTreesCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java)
               * [SegmentTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java)
               * [SplayTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SplayTree.java)
+              * [Treap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/Treap.java)
               * [TreeRandomNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java)
               * [TrieImp](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java)
               * [VerticalOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java)
@@ -457,6 +459,7 @@
             * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java)
           * scheduling
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
+            * [MLFQScheduler](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
             * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
@@ -618,6 +621,7 @@
           * ciphers
             * a5
               * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
+            * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
             * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
             * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
             * [DESTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DESTest.java)
@@ -728,6 +732,7 @@
               * [PreOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/PreOrderTraversalTest.java)
               * [SameTreesCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SameTreesCheckTest.java)
               * [SplayTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java)
+              * [TreapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java)
               * [TreeTestUtils](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java)
               * [TrieImpTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TrieImpTest.java)
               * [VerticalOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversalTest.java)
@@ -911,6 +916,7 @@
             * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java)
           * scheduling
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
+            * [MLFQSchedulerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
             * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java b/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java
new file mode 100644
index 000000000000..75840a5cbdcf
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java
@@ -0,0 +1,148 @@
+package com.thealgorithms.scheduling;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+/**
+ * The Multi-Level Feedback Queue (MLFQ) Scheduler class.
+ * This class simulates scheduling using multiple queues, where processes move
+ * between queues depending on their CPU burst behavior.
+ */
+public class MLFQScheduler {
+    private List<Queue<Process>> queues; // Multi-level feedback queues
+    private int[] timeQuantum; // Time quantum for each queue level
+    private int currentTime; // Current time in the system
+
+    /**
+     * Constructor to initialize the MLFQ scheduler with the specified number of
+     * levels and their corresponding time quantums.
+     *
+     * @param levels       Number of queues (priority levels)
+     * @param timeQuantums Time quantum for each queue level
+     */
+    public MLFQScheduler(int levels, int[] timeQuantums) {
+        queues = new ArrayList<>(levels);
+        for (int i = 0; i < levels; i++) {
+            queues.add(new LinkedList<>());
+        }
+        timeQuantum = timeQuantums;
+        currentTime = 0;
+    }
+
+    /**
+     * Adds a new process to the highest priority queue (queue 0).
+     *
+     * @param p The process to be added to the scheduler
+     */
+    public void addProcess(Process p) {
+        queues.get(0).add(p);
+    }
+
+    /**
+     * Executes the scheduling process by running the processes in all queues,
+     * promoting or demoting them based on their completion status and behavior.
+     * The process continues until all queues are empty.
+     */
+    public void run() {
+        while (!allQueuesEmpty()) {
+            for (int i = 0; i < queues.size(); i++) {
+                Queue<Process> queue = queues.get(i);
+                if (!queue.isEmpty()) {
+                    Process p = queue.poll();
+                    int quantum = timeQuantum[i];
+
+                    // Execute the process for the minimum of the time quantum or the remaining time
+                    int timeSlice = Math.min(quantum, p.remainingTime);
+                    p.execute(timeSlice);
+                    currentTime += timeSlice; // Update the system's current time
+
+                    if (p.isFinished()) {
+                        System.out.println("Process " + p.pid + " finished at time " + currentTime);
+                    } else {
+                        if (i < queues.size() - 1) {
+                            p.priority++; // Demote the process to the next lower priority queue
+                            queues.get(i + 1).add(p); // Add to the next queue level
+                        } else {
+                            queue.add(p); // Stay in the same queue if it's the last level
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Helper function to check if all the queues are empty (i.e., no process is
+     * left to execute).
+     *
+     * @return true if all queues are empty, otherwise false
+     */
+    private boolean allQueuesEmpty() {
+        for (Queue<Process> queue : queues) {
+            if (!queue.isEmpty()) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Retrieves the current time of the scheduler, which reflects the total time
+     * elapsed during the execution of all processes.
+     *
+     * @return The current time in the system
+     */
+    public int getCurrentTime() {
+        return currentTime;
+    }
+}
+
+/**
+ * Represents a process in the Multi-Level Feedback Queue (MLFQ) scheduling
+ * algorithm.
+ */
+class Process {
+    int pid;
+    int burstTime;
+    int remainingTime;
+    int arrivalTime;
+    int priority;
+
+    /**
+     * Constructor to initialize a new process.
+     *
+     * @param pid         Process ID
+     * @param burstTime   CPU Burst Time (time required for the process)
+     * @param arrivalTime Arrival time of the process
+     */
+    Process(int pid, int burstTime, int arrivalTime) {
+        this.pid = pid;
+        this.burstTime = burstTime;
+        this.remainingTime = burstTime;
+        this.arrivalTime = arrivalTime;
+        this.priority = 0;
+    }
+
+    /**
+     * Executes the process for a given time slice.
+     *
+     * @param timeSlice The amount of time the process is executed
+     */
+    public void execute(int timeSlice) {
+        remainingTime -= timeSlice;
+        if (remainingTime < 0) {
+            remainingTime = 0;
+        }
+    }
+
+    /**
+     * Checks if the process has finished execution.
+     *
+     * @return true if the process is finished, otherwise false
+     */
+    public boolean isFinished() {
+        return remainingTime == 0;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java b/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java
new file mode 100644
index 000000000000..d7d27e9b32b6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java
@@ -0,0 +1,46 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class MLFQSchedulerTest {
+
+    @Test
+    void testMLFQScheduling() {
+        // Create MLFQ Scheduler with 3 levels and time quantum for each level
+        int[] timeQuantums = {4, 8, 12}; // Example of different quantum for each queue
+        MLFQScheduler scheduler = new MLFQScheduler(3, timeQuantums);
+
+        // Add processes to the scheduler
+        scheduler.addProcess(new Process(1, 10, 0)); // pid=1, burstTime=10, arrivalTime=0
+        scheduler.addProcess(new Process(2, 15, 0)); // pid=2, burstTime=15, arrivalTime=0
+        scheduler.addProcess(new Process(3, 25, 0)); // pid=3, burstTime=25, arrivalTime=0
+
+        // Run the scheduler
+        scheduler.run();
+
+        // Check current time after all processes are finished
+        assertEquals(50, scheduler.getCurrentTime());
+    }
+
+    @Test
+    void testProcessCompletionOrder() {
+        int[] timeQuantums = {3, 6, 9};
+        MLFQScheduler scheduler = new MLFQScheduler(3, timeQuantums);
+
+        Process p1 = new Process(1, 10, 0);
+        Process p2 = new Process(2, 5, 0);
+        Process p3 = new Process(3, 20, 0);
+
+        scheduler.addProcess(p1);
+        scheduler.addProcess(p2);
+        scheduler.addProcess(p3);
+
+        scheduler.run();
+
+        // After running, current time should match the total burst time for all
+        // processes
+        assertEquals(35, scheduler.getCurrentTime());
+    }
+}

From b190cb72def8d926e2f73d9f80cfd27c88ff3a3a Mon Sep 17 00:00:00 2001
From: Gopi Gorantala <gopishiva001@outlook.com>
Date: Sun, 6 Oct 2024 12:45:32 +0530
Subject: [PATCH 0429/1338] Add countsetbits problem with lookup table approach
 (#5573)

---
 .../bitmanipulation/CountSetBits.java         | 28 +++++++++++++++++++
 .../bitmanipulation/CountSetBitsTest.java     |  9 ++++++
 2 files changed, 37 insertions(+)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java b/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java
index eb0886e30292..242f35fc35f2 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java
@@ -48,4 +48,32 @@ public long countSetBits(long num) {
         }
         return cnt;
     }
+
+    /**
+     * This approach takes O(1) running time to count the set bits, but requires a pre-processing.
+     *
+     * So, we divide our 32-bit input into 8-bit chunks, with four chunks. We have 8 bits in each chunk.
+     *
+     * Then the range is from 0-255 (0 to 2^7).
+     * So, we may need to count set bits from 0 to 255 in individual chunks.
+     *
+     * @param num takes a long number
+     * @return the count of set bits in the binary equivalent
+     */
+    public int lookupApproach(int num) {
+        int[] table = new int[256];
+        table[0] = 0;
+
+        for (int i = 1; i < 256; i++) {
+            table[i] = (i & 1) + table[i >> 1]; // i >> 1 equals to i/2
+        }
+
+        int res = 0;
+        for (int i = 0; i < 4; i++) {
+            res += table[num & 0xff];
+            num >>= 8;
+        }
+
+        return res;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java
index 412312109bec..61e0757f9c12 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java
@@ -14,4 +14,13 @@ void testSetBits() {
         assertEquals(5, csb.countSetBits(10000));
         assertEquals(5, csb.countSetBits(31));
     }
+
+    @Test
+    void testSetBitsLookupApproach() {
+        CountSetBits csb = new CountSetBits();
+        assertEquals(1L, csb.lookupApproach(16));
+        assertEquals(4, csb.lookupApproach(15));
+        assertEquals(5, csb.lookupApproach(10000));
+        assertEquals(5, csb.lookupApproach(31));
+    }
 }

From afc06d56320f6a3d99af8270b75c11c760ff02a7 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 6 Oct 2024 23:11:29 +0530
Subject: [PATCH 0430/1338] Enhance class & function documentation in
 `LFUcache.java` (#5583)

* Enhance class & function documentation in `LFUcache.java`

* Fix

---------

Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 .../datastructures/caches/LFUCache.java       | 60 +++++++++++++++----
 1 file changed, 49 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java b/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
index a5b83af14551..4e233224e367 100644
--- a/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
+++ b/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
@@ -4,11 +4,27 @@
 import java.util.Map;
 
 /**
- * Java program for LFU Cache (https://en.wikipedia.org/wiki/Least_frequently_used)
+ * The {@code LFUCache} class implements a Least Frequently Used (LFU) cache.
+ * An LFU cache evicts the least frequently used item when the cache reaches its capacity.
+ * It keeps track of how many times each item is used and maintains a doubly linked list
+ * for efficient addition and removal of items based on their frequency of use.
+ *
+ * @param <K> The type of keys maintained by this cache.
+ * @param <V> The type of mapped values.
+ *
+ * <p>
+ * Reference: <a href="https://en.wikipedia.org/wiki/Least_frequently_used">LFU Cache - Wikipedia</a>
+ * </p>
+ *
  * @author Akshay Dubey (https://github.com/itsAkshayDubey)
  */
 public class LFUCache<K, V> {
 
+    /**
+     * The {@code Node} class represents an element in the LFU cache.
+     * Each node contains a key, a value, and a frequency count.
+     * It also has pointers to the previous and next nodes in the doubly linked list.
+     */
     private class Node {
         private final K key;
         private V value;
@@ -16,6 +32,13 @@ private class Node {
         private Node previous;
         private Node next;
 
+        /**
+         * Constructs a new {@code Node} with the specified key, value, and frequency.
+         *
+         * @param key The key associated with this node.
+         * @param value The value stored in this node.
+         * @param frequency The frequency of usage of this node.
+         */
         Node(K key, V value, int frequency) {
             this.key = key;
             this.value = value;
@@ -29,10 +52,19 @@ private class Node {
     private final int capacity;
     private static final int DEFAULT_CAPACITY = 100;
 
+    /**
+     * Constructs an LFU cache with the default capacity.
+     */
     public LFUCache() {
         this(DEFAULT_CAPACITY);
     }
 
+    /**
+     * Constructs an LFU cache with the specified capacity.
+     *
+     * @param capacity The maximum number of items that the cache can hold.
+     * @throws IllegalArgumentException if the specified capacity is less than or equal to zero.
+     */
     public LFUCache(int capacity) {
         if (capacity <= 0) {
             throw new IllegalArgumentException("Capacity must be greater than zero.");
@@ -42,10 +74,12 @@ public LFUCache(int capacity) {
     }
 
     /**
-     * Retrieves the value for the given key from the cache. Increases the frequency of the node.
+     * Retrieves the value associated with the given key from the cache.
+     * If the key exists, the node's frequency is increased and the node is repositioned
+     * in the linked list based on its updated frequency.
      *
-     * @param key The key to look up.
-     * @return The value associated with the key, or null if the key is not present.
+     * @param key The key whose associated value is to be returned.
+     * @return The value associated with the key, or {@code null} if the key is not present in the cache.
      */
     public V get(K key) {
         Node node = cache.get(key);
@@ -59,10 +93,12 @@ public V get(K key) {
     }
 
     /**
-     * Adds or updates a key-value pair in the cache. If the cache is full, the least frequently used item is evicted.
+     * Inserts or updates a key-value pair in the cache.
+     * If the key already exists, the value is updated and its frequency is incremented.
+     * If the cache is full, the least frequently used item is removed before inserting the new item.
      *
-     * @param key   The key to insert or update.
-     * @param value The value to insert or update.
+     * @param key The key associated with the value to be inserted or updated.
+     * @param value The value to be inserted or updated.
      */
     public void put(K key, V value) {
         if (cache.containsKey(key)) {
@@ -73,7 +109,7 @@ public void put(K key, V value) {
             addNodeWithUpdatedFrequency(node);
         } else {
             if (cache.size() >= capacity) {
-                cache.remove(this.head.key);
+                cache.remove(this.head.key); // Evict least frequently used item
                 removeNode(head);
             }
             Node node = new Node(key, value, 1);
@@ -84,8 +120,9 @@ public void put(K key, V value) {
 
     /**
      * Adds a node to the linked list in the correct position based on its frequency.
+     * The linked list is ordered by frequency, with the least frequently used node at the head.
      *
-     * @param node The node to add.
+     * @param node The node to be inserted into the list.
      */
     private void addNodeWithUpdatedFrequency(Node node) {
         if (tail != null && head != null) {
@@ -122,9 +159,10 @@ private void addNodeWithUpdatedFrequency(Node node) {
     }
 
     /**
-     * Removes a node from the linked list.
+     * Removes a node from the doubly linked list.
+     * This method ensures that the pointers of neighboring nodes are properly updated.
      *
-     * @param node The node to remove.
+     * @param node The node to be removed from the list.
      */
     private void removeNode(Node node) {
         if (node.previous != null) {

From ee6cd648bc4ea9e929548b8c93d841baf173925b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 6 Oct 2024 23:42:57 +0530
Subject: [PATCH 0431/1338] Strengthen class & function documentation in
 `CompositeLFSR.java` (#5596)

Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 .../ciphers/a5/CompositeLFSR.java             | 36 +++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java b/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java
index f96946c39490..029a93848c28 100644
--- a/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java
+++ b/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java
@@ -5,13 +5,33 @@
 import java.util.Map;
 import java.util.TreeMap;
 
+/**
+ * The CompositeLFSR class represents a composite implementation of
+ * Linear Feedback Shift Registers (LFSRs) for cryptographic purposes.
+ *
+ * <p>
+ * This abstract class manages a collection of LFSR instances and
+ * provides a mechanism for irregular clocking based on the
+ * majority bit among the registers. It implements the BaseLFSR
+ * interface, requiring subclasses to define specific LFSR behaviors.
+ * </p>
+ */
 public abstract class CompositeLFSR implements BaseLFSR {
 
     protected final List<LFSR> registers = new ArrayList<>();
 
     /**
-     * Implements irregular clocking using the clock bit for each register
-     * @return the registers discarded bit xored value
+     * Performs a clocking operation on the composite LFSR.
+     *
+     * <p>
+     * This method determines the majority bit across all registers and
+     * clocks each register based on its clock bit. If a register's
+     * clock bit matches the majority bit, it is clocked (shifted).
+     * The method also computes and returns the XOR of the last bits
+     * of all registers.
+     * </p>
+     *
+     * @return the XOR value of the last bits of all registers.
      */
     @Override
     public boolean clock() {
@@ -26,6 +46,18 @@ public boolean clock() {
         return result;
     }
 
+    /**
+     * Calculates the majority bit among all registers.
+     *
+     * <p>
+     * This private method counts the number of true and false clock bits
+     * across all LFSR registers. It returns true if the count of true
+     * bits is greater than or equal to the count of false bits; otherwise,
+     * it returns false.
+     * </p>
+     *
+     * @return true if the majority clock bits are true; false otherwise.
+     */
     private boolean getMajorityBit() {
         Map<Boolean, Integer> bitCount = new TreeMap<>();
         bitCount.put(Boolean.FALSE, 0);

From 2001a097e2ab9fd2f63d444ace41cf3c59e2e251 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 16:55:08 +0530
Subject: [PATCH 0432/1338] Add `HighestResponseRatioNextScheduling.java` new
 algorithm with tests (#5607)

* Add `HighestResponseRatioNextScheduling.java` new algorithm with tests

* Update directory

* Improve class documentation

* Update directory

* Fix

* Fix

* Fix

* Add suggested changes

* Fix clang errors

---------

Co-authored-by: Hardvan <Hardvan@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 DIRECTORY.md                                  |   2 +
 .../HighestResponseRatioNextScheduling.java   | 158 ++++++++++++++++++
 ...ighestResponseRatioNextSchedulingTest.java | 112 +++++++++++++
 3 files changed, 272 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index d93dde3dffb6..7e9f5357a825 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -459,6 +459,7 @@
             * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java)
           * scheduling
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
+            * [HighestResponseRatioNextScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
             * [MLFQScheduler](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
@@ -916,6 +917,7 @@
             * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java)
           * scheduling
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
+            * [HighestResponseRatioNextSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
             * [MLFQSchedulerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java b/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java
new file mode 100644
index 000000000000..8ed689698557
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java
@@ -0,0 +1,158 @@
+package com.thealgorithms.scheduling;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+/**
+ * The {@code HighestResponseRatioNextScheduling} class implements the
+ * Highest Response Ratio Next (HRRN) scheduling algorithm.
+ * HRRN is a non-preemptive scheduling algorithm that selects the process with
+ * the highest response ratio for execution.
+ * The response ratio is calculated as:
+ *
+ * <pre>
+ *     Response Ratio = (waiting time + burst time) / burst time
+ * </pre>
+ *
+ * HRRN is designed to reduce the average waiting time and improve overall
+ * system performance by balancing between short and long processes,
+ * minimizing process starvation.
+ */
+public final class HighestResponseRatioNextScheduling {
+
+    private static final int PROCESS_NOT_FOUND = -1;
+    private static final double INITIAL_MAX_RESPONSE_RATIO = -1.0;
+
+    private HighestResponseRatioNextScheduling() {
+    }
+
+    /**
+     * Represents a process in the scheduling algorithm.
+     */
+    private static class Process {
+        String name;
+        int arrivalTime;
+        int burstTime;
+        int turnAroundTime;
+        boolean finished;
+
+        Process(String name, int arrivalTime, int burstTime) {
+            this.name = name;
+            this.arrivalTime = arrivalTime;
+            this.burstTime = burstTime;
+            this.turnAroundTime = 0;
+            this.finished = false;
+        }
+
+        /**
+         * Calculates the response ratio for this process.
+         *
+         * @param currentTime The current time in the scheduling process.
+         * @return The response ratio for this process.
+         */
+        double calculateResponseRatio(int currentTime) {
+            return (double) (burstTime + currentTime - arrivalTime) / burstTime;
+        }
+    }
+
+    /**
+     * Calculates the Turn Around Time (TAT) for each process.
+     *
+     * <p>Turn Around Time is calculated as the total time a process spends
+     * in the system from arrival to completion. It is the sum of the burst time
+     * and the waiting time.</p>
+     *
+     * @param processNames Array of process names.
+     * @param arrivalTimes Array of arrival times corresponding to each process.
+     * @param burstTimes Array of burst times for each process.
+     * @param noOfProcesses The number of processes.
+     * @return An array of Turn Around Times for each process.
+     */
+    public static int[] calculateTurnAroundTime(final String[] processNames, final int[] arrivalTimes, final int[] burstTimes, final int noOfProcesses) {
+        int currentTime = 0;
+        int[] turnAroundTime = new int[noOfProcesses];
+        Process[] processes = new Process[noOfProcesses];
+
+        for (int i = 0; i < noOfProcesses; i++) {
+            processes[i] = new Process(processNames[i], arrivalTimes[i], burstTimes[i]);
+        }
+
+        Arrays.sort(processes, Comparator.comparingInt(p -> p.arrivalTime));
+
+        int finishedProcessCount = 0;
+        while (finishedProcessCount < noOfProcesses) {
+            int nextProcessIndex = findNextProcess(processes, currentTime);
+            if (nextProcessIndex == PROCESS_NOT_FOUND) {
+                currentTime++;
+                continue;
+            }
+
+            Process currentProcess = processes[nextProcessIndex];
+            currentTime = Math.max(currentTime, currentProcess.arrivalTime);
+            currentProcess.turnAroundTime = currentTime + currentProcess.burstTime - currentProcess.arrivalTime;
+            currentTime += currentProcess.burstTime;
+            currentProcess.finished = true;
+            finishedProcessCount++;
+        }
+
+        for (int i = 0; i < noOfProcesses; i++) {
+            turnAroundTime[i] = processes[i].turnAroundTime;
+        }
+
+        return turnAroundTime;
+    }
+
+    /**
+     * Calculates the Waiting Time (WT) for each process.
+     *
+     * @param turnAroundTime The Turn Around Times for each process.
+     * @param burstTimes The burst times for each process.
+     * @return An array of Waiting Times for each process.
+     */
+    public static int[] calculateWaitingTime(int[] turnAroundTime, int[] burstTimes) {
+        int[] waitingTime = new int[turnAroundTime.length];
+        for (int i = 0; i < turnAroundTime.length; i++) {
+            waitingTime[i] = turnAroundTime[i] - burstTimes[i];
+        }
+        return waitingTime;
+    }
+
+    /**
+     * Finds the next process to be scheduled based on arrival times and the current time.
+     *
+     * @param processes Array of Process objects.
+     * @param currentTime The current time in the scheduling process.
+     * @return The index of the next process to be scheduled, or PROCESS_NOT_FOUND if no process is ready.
+     */
+    private static int findNextProcess(Process[] processes, int currentTime) {
+        return findHighestResponseRatio(processes, currentTime);
+    }
+
+    /**
+     * Finds the process with the highest response ratio.
+     *
+     * <p>The response ratio is calculated as:
+     * (waiting time + burst time) / burst time
+     * where waiting time = current time - arrival time</p>
+     *
+     * @param processes Array of Process objects.
+     * @param currentTime The current time in the scheduling process.
+     * @return The index of the process with the highest response ratio, or PROCESS_NOT_FOUND if no process is ready.
+     */
+    private static int findHighestResponseRatio(Process[] processes, int currentTime) {
+        double maxResponseRatio = INITIAL_MAX_RESPONSE_RATIO;
+        int maxIndex = PROCESS_NOT_FOUND;
+
+        for (int i = 0; i < processes.length; i++) {
+            Process process = processes[i];
+            if (!process.finished && process.arrivalTime <= currentTime) {
+                double responseRatio = process.calculateResponseRatio(currentTime);
+                if (responseRatio > maxResponseRatio) {
+                    maxResponseRatio = responseRatio;
+                    maxIndex = i;
+                }
+            }
+        }
+        return maxIndex;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java
new file mode 100644
index 000000000000..d225d76b82c9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java
@@ -0,0 +1,112 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class HighestResponseRatioNextSchedulingTest {
+
+    @Test
+    public void testCalculateTurnAroundTime() {
+        String[] processNames = {"A", "B", "C"};
+        int[] arrivalTimes = {0, 2, 4};
+        int[] burstTimes = {3, 1, 2};
+        int noOfProcesses = 3;
+
+        int[] expectedTurnAroundTimes = {3, 2, 2};
+        int[] actualTurnAroundTimes = HighestResponseRatioNextScheduling.calculateTurnAroundTime(processNames, arrivalTimes, burstTimes, noOfProcesses);
+
+        assertArrayEquals(expectedTurnAroundTimes, actualTurnAroundTimes, "Turn Around Times do not match");
+    }
+
+    @Test
+    public void testCalculateWaitingTime() {
+        int[] turnAroundTimes = {3, 1, 5};
+        int[] burstTimes = {3, 1, 2};
+
+        int[] expectedWaitingTimes = {0, 0, 3};
+        int[] actualWaitingTimes = HighestResponseRatioNextScheduling.calculateWaitingTime(turnAroundTimes, burstTimes);
+
+        assertArrayEquals(expectedWaitingTimes, actualWaitingTimes, "Waiting Times do not match");
+    }
+
+    @Test
+    public void testCompleteSchedulingScenario() {
+        String[] processNames = {"A", "B", "C"};
+        int[] arrivalTimes = {0, 1, 2};
+        int[] burstTimes = {5, 2, 1};
+
+        int[] expectedTurnAroundTimes = {5, 7, 4};
+        int[] turnAroundTimes = HighestResponseRatioNextScheduling.calculateTurnAroundTime(processNames, arrivalTimes, burstTimes, processNames.length);
+        assertArrayEquals(expectedTurnAroundTimes, turnAroundTimes, "Turn Around Times do not match");
+
+        int[] expectedWaitingTimes = {0, 5, 3};
+        int[] waitingTimes = HighestResponseRatioNextScheduling.calculateWaitingTime(turnAroundTimes, burstTimes);
+        assertArrayEquals(expectedWaitingTimes, waitingTimes, "Waiting Times do not match");
+    }
+
+    @Test
+    public void testZeroProcesses() {
+        String[] processNames = {};
+        int[] arrivalTimes = {};
+        int[] burstTimes = {};
+        int noOfProcesses = 0;
+
+        int[] expectedTurnAroundTimes = {};
+        int[] actualTurnAroundTimes = HighestResponseRatioNextScheduling.calculateTurnAroundTime(processNames, arrivalTimes, burstTimes, noOfProcesses);
+
+        assertArrayEquals(expectedTurnAroundTimes, actualTurnAroundTimes, "Turn Around Times for zero processes should be an empty array");
+    }
+
+    @Test
+    public void testAllProcessesArriveAtSameTime() {
+        String[] processNames = {"A", "B", "C", "D"};
+        int[] arrivalTimes = {0, 0, 0, 0};
+        int[] burstTimes = {4, 3, 1, 2};
+        int noOfProcesses = 4;
+
+        int[] expectedTurnAroundTimes = {4, 10, 5, 7};
+        int[] actualTurnAroundTimes = HighestResponseRatioNextScheduling.calculateTurnAroundTime(processNames, arrivalTimes, burstTimes, noOfProcesses);
+
+        assertArrayEquals(expectedTurnAroundTimes, actualTurnAroundTimes, "Turn Around Times for processes arriving at the same time do not match");
+    }
+
+    @Test
+    public void testProcessesWithZeroBurstTime() {
+        String[] processNames = {"A", "B", "C"};
+        int[] arrivalTimes = {0, 1, 2};
+        int[] burstTimes = {3, 0, 2};
+        int noOfProcesses = 3;
+
+        int[] expectedTurnAroundTimes = {3, 2, 3};
+        int[] actualTurnAroundTimes = HighestResponseRatioNextScheduling.calculateTurnAroundTime(processNames, arrivalTimes, burstTimes, noOfProcesses);
+
+        assertArrayEquals(expectedTurnAroundTimes, actualTurnAroundTimes, "Turn Around Times for processes with zero burst time do not match");
+    }
+
+    @Test
+    public void testProcessesWithLargeGapsBetweenArrivals() {
+        String[] processNames = {"A", "B", "C"};
+        int[] arrivalTimes = {0, 100, 200};
+        int[] burstTimes = {10, 10, 10};
+        int noOfProcesses = 3;
+
+        int[] expectedTurnAroundTimes = {10, 10, 10};
+        int[] actualTurnAroundTimes = HighestResponseRatioNextScheduling.calculateTurnAroundTime(processNames, arrivalTimes, burstTimes, noOfProcesses);
+
+        assertArrayEquals(expectedTurnAroundTimes, actualTurnAroundTimes, "Turn Around Times for processes with large gaps between arrivals do not match");
+    }
+
+    @Test
+    public void testProcessesWithVeryLargeBurstTimes() {
+        String[] processNames = {"A", "B"};
+        int[] arrivalTimes = {0, 1};
+        int[] burstTimes = {Integer.MAX_VALUE / 2, Integer.MAX_VALUE / 2};
+        int noOfProcesses = 2;
+
+        int[] expectedTurnAroundTimes = {Integer.MAX_VALUE / 2, Integer.MAX_VALUE - 2};
+        int[] actualTurnAroundTimes = HighestResponseRatioNextScheduling.calculateTurnAroundTime(processNames, arrivalTimes, burstTimes, noOfProcesses);
+
+        assertArrayEquals(expectedTurnAroundTimes, actualTurnAroundTimes, "Turn Around Times for processes with very large burst times do not match");
+    }
+}

From 387707ffe530bd3b296443700ac08455256b618a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 17:01:13 +0530
Subject: [PATCH 0433/1338] Refactor BipartiteGraphDFS.java, add Junit tests
 (#5606)

* Refactor `BipartiteGraphDFS.java`, add Junit tests

* Update directory

* Fix

* Add suggested changes

* Update BipartiteGraphDFS.java

---------

Co-authored-by: Hardvan <Hardvan@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 DIRECTORY.md                                  |  1 +
 .../graphs/BipartiteGraphDFS.java             | 78 ++++++++++---------
 .../graphs/BipartiteGraphDFSTest.java         | 73 +++++++++++++++++
 3 files changed, 114 insertions(+), 38 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7e9f5357a825..d3136f95c062 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -676,6 +676,7 @@
             * dynamicarray
               * [DynamicArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java)
             * graphs
+              * [BipartiteGraphDFSTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java)
               * [BoruvkaAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
               * [DijkstraAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java)
               * [EdmondsBlossomAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java b/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java
index e8d2b8fd0a04..15ae5225533c 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java
@@ -1,23 +1,49 @@
 package com.thealgorithms.datastructures.graphs;
 
-import java.io.BufferedReader;
-import java.io.IOException;
-import java.io.InputStreamReader;
 import java.util.ArrayList;
 import java.util.Arrays;
 
 /**
- * Given an adjacency list of a graph adj of V no. of vertices having 0 based
- * index. Check whether the graph is bipartite or not.
+ * This class provides a method to check if a given undirected graph is bipartite using Depth-First Search (DFS).
+ * A bipartite graph is a graph whose vertices can be divided into two disjoint sets such that no two vertices
+ * within the same set are adjacent. In other words, all edges must go between the two sets.
  *
- * Input : {{0, 1, 0, 1}, {1, 0, 1, 0}, {0, 1, 0, 1}, {1, 0, 1, 0}}
+ * The implementation leverages DFS to attempt to color the graph using two colors. If we can color the graph such
+ * that no two adjacent vertices have the same color, the graph is bipartite.
  *
- * Output : YES
+ * Example:
+ * Input (Adjacency Matrix):
+ * {{0, 1, 0, 1},
+ *  {1, 0, 1, 0},
+ *  {0, 1, 0, 1},
+ *  {1, 0, 1, 0}}
+ *
+ * Output: YES (This graph is bipartite)
+ *
+ * Input (Adjacency Matrix):
+ * {{0, 1, 1, 0},
+ *  {1, 0, 1, 0},
+ *  {1, 1, 0, 1},
+ *  {0, 0, 1, 0}}
+ *
+ * Output: NO (This graph is not bipartite)
  */
 public final class BipartiteGraphDFS {
     private BipartiteGraphDFS() {
     }
 
+    /**
+     * Helper method to perform DFS and check if the graph is bipartite.
+     *
+     * During DFS traversal, this method attempts to color each vertex in such a way
+     * that no two adjacent vertices share the same color.
+     *
+     * @param v     Number of vertices in the graph
+     * @param adj   Adjacency list of the graph where each index i contains a list of adjacent vertices
+     * @param color Array to store the color assigned to each vertex (-1 indicates uncolored)
+     * @param node  Current vertex being processed
+     * @return      True if the graph (or component of the graph) is bipartite, otherwise false
+     */
     private static boolean bipartite(int v, ArrayList<ArrayList<Integer>> adj, int[] color, int node) {
         if (color[node] == -1) {
             color[node] = 1;
@@ -35,11 +61,16 @@ private static boolean bipartite(int v, ArrayList<ArrayList<Integer>> adj, int[]
         return true;
     }
 
+    /**
+     * Method to check if the graph is bipartite.
+     *
+     * @param v   Number of vertices in the graph
+     * @param adj Adjacency list of the graph
+     * @return    True if the graph is bipartite, otherwise false
+     */
     public static boolean isBipartite(int v, ArrayList<ArrayList<Integer>> adj) {
-        // Code here
         int[] color = new int[v + 1];
         Arrays.fill(color, -1);
-
         for (int i = 0; i < v; i++) {
             if (color[i] == -1) {
                 if (!bipartite(v, adj, color, i)) {
@@ -49,33 +80,4 @@ public static boolean isBipartite(int v, ArrayList<ArrayList<Integer>> adj) {
         }
         return true;
     }
-
-    public static void main(String[] args) throws IOException {
-        BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
-        int t = Integer.parseInt(read.readLine().trim());
-        while (t-- > 0) {
-            String[] str1 = read.readLine().trim().split(" ");
-            int numVertices = Integer.parseInt(str1[0]);
-            int numEdges = Integer.parseInt(str1[1]);
-
-            ArrayList<ArrayList<Integer>> adj = new ArrayList<>();
-            for (int i = 0; i < numVertices; i++) {
-                adj.add(new ArrayList<>());
-            }
-            for (int i = 0; i < numEdges; i++) {
-                String[] str2 = read.readLine().trim().split(" ");
-                int vertexU = Integer.parseInt(str2[0]);
-                int vertexV = Integer.parseInt(str2[1]);
-                adj.get(vertexU).add(vertexV);
-                adj.get(vertexV).add(vertexU);
-            }
-
-            boolean ans = isBipartite(numVertices, adj);
-            if (ans) {
-                System.out.println("YES");
-            } else {
-                System.out.println("NO");
-            }
-        }
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java
new file mode 100644
index 000000000000..75fa6adc3014
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java
@@ -0,0 +1,73 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import org.junit.jupiter.api.Test;
+
+public class BipartiteGraphDFSTest {
+
+    // Helper method to create an adjacency list from edges
+    private ArrayList<ArrayList<Integer>> createAdjacencyList(int numVertices, int[][] edges) {
+        ArrayList<ArrayList<Integer>> adj = new ArrayList<>();
+        for (int i = 0; i < numVertices; i++) {
+            adj.add(new ArrayList<>());
+        }
+        for (int[] edge : edges) {
+            int vertexU = edge[0];
+            int vertexV = edge[1];
+            adj.get(vertexU).add(vertexV);
+            adj.get(vertexV).add(vertexU);
+        }
+        return adj;
+    }
+
+    @Test
+    public void testBipartiteGraphEvenCycle() {
+        int numVertices = 4;
+        int[][] edges = {{0, 1}, {1, 2}, {2, 3}, {3, 0}}; // Even cycle
+        ArrayList<ArrayList<Integer>> adj = createAdjacencyList(numVertices, edges);
+        assertTrue(BipartiteGraphDFS.isBipartite(numVertices, adj), "Graph should be bipartite (even cycle)");
+    }
+
+    @Test
+    public void testBipartiteGraphOddCycle() {
+        int numVertices = 5;
+        int[][] edges = {{0, 1}, {1, 2}, {2, 0}, {1, 3}, {3, 4}}; // Odd cycle
+        ArrayList<ArrayList<Integer>> adj = createAdjacencyList(numVertices, edges);
+        assertFalse(BipartiteGraphDFS.isBipartite(numVertices, adj), "Graph should not be bipartite (odd cycle)");
+    }
+
+    @Test
+    public void testBipartiteGraphDisconnected() {
+        int numVertices = 6;
+        int[][] edges = {{0, 1}, {2, 3}, {4, 5}}; // Disconnected bipartite graphs
+        ArrayList<ArrayList<Integer>> adj = createAdjacencyList(numVertices, edges);
+        assertTrue(BipartiteGraphDFS.isBipartite(numVertices, adj), "Graph should be bipartite (disconnected)");
+    }
+
+    @Test
+    public void testBipartiteGraphSingleVertex() {
+        int numVertices = 1;
+        int[][] edges = {}; // Single vertex, no edges
+        ArrayList<ArrayList<Integer>> adj = createAdjacencyList(numVertices, edges);
+        assertTrue(BipartiteGraphDFS.isBipartite(numVertices, adj), "Graph should be bipartite (single vertex)");
+    }
+
+    @Test
+    public void testBipartiteGraphCompleteBipartite() {
+        int numVertices = 4;
+        int[][] edges = {{0, 2}, {0, 3}, {1, 2}, {1, 3}}; // K2,2 (Complete bipartite graph)
+        ArrayList<ArrayList<Integer>> adj = createAdjacencyList(numVertices, edges);
+        assertTrue(BipartiteGraphDFS.isBipartite(numVertices, adj), "Graph should be bipartite (complete bipartite)");
+    }
+
+    @Test
+    public void testBipartiteGraphNonBipartite() {
+        int numVertices = 3;
+        int[][] edges = {{0, 1}, {1, 2}, {2, 0}}; // Triangle (odd cycle)
+        ArrayList<ArrayList<Integer>> adj = createAdjacencyList(numVertices, edges);
+        assertFalse(BipartiteGraphDFS.isBipartite(numVertices, adj), "Graph should not be bipartite (triangle)");
+    }
+}

From 2cdd97cf5f076cccc640a2d75504636e8816f8f8 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 17:32:57 +0530
Subject: [PATCH 0434/1338] Improve class & function documentation in
 `HighestSetBit.java` (#5577)

---
 .../bitmanipulation/HighestSetBit.java        | 32 ++++++++++++++++---
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java b/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java
index 6b53b1aa182b..2398b8214371 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java
@@ -1,17 +1,39 @@
 package com.thealgorithms.bitmanipulation;
+
 import java.util.Optional;
 
 /**
  * Find Highest Set Bit
- * This class provides a function calculating the position (or index)
- * of the most significant bit being set to 1 in a given integer.
- * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
+ *
+ * This class provides a utility method to calculate the position of the highest
+ * (most significant) bit that is set to 1 in a given non-negative integer.
+ * It is often used in bit manipulation tasks to find the left-most set bit in binary
+ * representation of a number.
+ *
+ * Example:
+ * - For input 18 (binary 10010), the highest set bit is at position 4 (zero-based index).
+ *
+ * @author Bama Charan Chhandogi
+ * @version 1.0
+ * @since 2021-06-23
  */
-
 public final class HighestSetBit {
+
     private HighestSetBit() {
     }
 
+    /**
+     * Finds the highest (most significant) set bit in the given integer.
+     * The method returns the position (index) of the highest set bit as an {@link Optional}.
+     *
+     * - If the number is 0, no bits are set, and the method returns {@link Optional#empty()}.
+     * - If the number is negative, the method throws {@link IllegalArgumentException}.
+     *
+     * @param num The input integer for which the highest set bit is to be found. It must be non-negative.
+     * @return An {@link Optional} containing the index of the highest set bit (zero-based).
+     *         Returns {@link Optional#empty()} if the number is 0.
+     * @throws IllegalArgumentException if the input number is negative.
+     */
     public static Optional<Integer> findHighestSetBit(int num) {
         if (num < 0) {
             throw new IllegalArgumentException("Input cannot be negative");
@@ -27,6 +49,6 @@ public static Optional<Integer> findHighestSetBit(int num) {
             position++;
         }
 
-        return Optional.of(position - 1);
+        return Optional.of(position - 1); // Subtract 1 to convert to zero-based index
     }
 }

From 9ce9443fa243b7a9c3ba5800f547ee87001ed295 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 17:36:08 +0530
Subject: [PATCH 0435/1338] Enhance class & function documentation in
 `WordSearch.java` (#5578)

---
 .../backtracking/WordSearch.java              | 92 ++++++++++++-------
 1 file changed, 61 insertions(+), 31 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/WordSearch.java b/src/main/java/com/thealgorithms/backtracking/WordSearch.java
index f3a5b0433727..174ca90ccaab 100644
--- a/src/main/java/com/thealgorithms/backtracking/WordSearch.java
+++ b/src/main/java/com/thealgorithms/backtracking/WordSearch.java
@@ -1,35 +1,39 @@
 package com.thealgorithms.backtracking;
 
-/*
-Word Search Problem (https://en.wikipedia.org/wiki/Word_search)
-
-Given an m x n grid of characters board and a string word, return true if word exists in the grid.
-
-The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are
-those horizontally or vertically neighboring. The same letter cell may not be used more than once.
-
-For example,
-Given board =
-
-[
- ['A','B','C','E'],
- ['S','F','C','S'],
- ['A','D','E','E']
-]
-word = "ABCCED", -> returns true,
-word = "SEE", -> returns true,
-word = "ABCB", -> returns false.
-*/
-
-/*
-   Solution
-   Depth First Search in matrix (as multiple sources possible) with backtracking
-   like finding cycle in a directed graph. Maintain a record of path
-
-   Tx = O(m * n * 3^L): for each cell, we look at 3 options (not 4 as that one will be visited), we
-   do it L times Sx = O(L) : stack size is max L
-*/
-
+/**
+ * Word Search Problem
+ *
+ * This class solves the word search problem where given an m x n grid of characters (board)
+ * and a target word, the task is to check if the word exists in the grid.
+ * The word can be constructed from sequentially adjacent cells (horizontally or vertically),
+ * and the same cell may not be used more than once in constructing the word.
+ *
+ * Example:
+ * - For board =
+ *     [
+ *       ['A','B','C','E'],
+ *       ['S','F','C','S'],
+ *       ['A','D','E','E']
+ *     ]
+ *   and word = "ABCCED", -> returns true
+ *   and word = "SEE",    -> returns true
+ *   and word = "ABCB",   -> returns false
+ *
+ * Solution:
+ * - Depth First Search (DFS) with backtracking is used to explore possible paths from any cell
+ *   matching the first letter of the word. DFS ensures that we search all valid paths, while
+ *   backtracking helps in reverting decisions when a path fails to lead to a solution.
+ *
+ * Time Complexity: O(m * n * 3^L)
+ *  - m = number of rows in the board
+ *  - n = number of columns in the board
+ *  - L = length of the word
+ *  - For each cell, we look at 3 possible directions (since we exclude the previously visited direction),
+ *    and we do this for L letters.
+ *
+ * Space Complexity: O(L)
+ *  - Stack space for the recursive DFS function, where L is the maximum depth of recursion (length of the word).
+ */
 public class WordSearch {
     private final int[] dx = {0, 0, 1, -1};
     private final int[] dy = {1, -1, 0, 0};
@@ -37,15 +41,32 @@ public class WordSearch {
     private char[][] board;
     private String word;
 
+    /**
+     * Checks if the given (x, y) coordinates are valid positions in the board.
+     *
+     * @param x The row index.
+     * @param y The column index.
+     * @return True if the coordinates are within the bounds of the board; false otherwise.
+     */
     private boolean isValid(int x, int y) {
         return x >= 0 && x < board.length && y >= 0 && y < board[0].length;
     }
 
+    /**
+     * Performs Depth First Search (DFS) from the cell (x, y)
+     * to search for the next character in the word.
+     *
+     * @param x       The current row index.
+     * @param y       The current column index.
+     * @param nextIdx The index of the next character in the word to be matched.
+     * @return True if a valid path is found to match the remaining characters of the word; false otherwise.
+     */
     private boolean doDFS(int x, int y, int nextIdx) {
         visited[x][y] = true;
         if (nextIdx == word.length()) {
             return true;
         }
+
         for (int i = 0; i < 4; ++i) {
             int xi = x + dx[i];
             int yi = y + dy[i];
@@ -56,10 +77,19 @@ private boolean doDFS(int x, int y, int nextIdx) {
                 }
             }
         }
-        visited[x][y] = false;
+
+        visited[x][y] = false; // Backtrack
         return false;
     }
 
+    /**
+     * Main function to check if the word exists in the board. It initiates DFS from any
+     * cell that matches the first character of the word.
+     *
+     * @param board The 2D grid of characters (the board).
+     * @param word  The target word to search for in the board.
+     * @return True if the word exists in the board; false otherwise.
+     */
     public boolean exist(char[][] board, String word) {
         this.board = board;
         this.word = word;

From dea806ea53430ac7bdc6d466f5a95e8c425d4c54 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 17:39:58 +0530
Subject: [PATCH 0436/1338] Add tests for `ClosestPair.java` (#5555)

---
 DIRECTORY.md                                  |  1 +
 .../divideandconquer/ClosestPair.java         |  2 +-
 .../divideandconquer/ClosestPairTest.java     | 75 +++++++++++++++++++
 3 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index d3136f95c062..6b44fa336a3a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -741,6 +741,7 @@
               * [ZigzagTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/ZigzagTraversalTest.java)
           * divideandconquer
             * [BinaryExponentiationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java)
+            * [ClosestPairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java)
             * [SkylineAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java)
             * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
           * dynamicprogramming
diff --git a/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java b/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java
index aa453539ac94..cd26f9213651 100644
--- a/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java
+++ b/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java
@@ -13,7 +13,7 @@ public final class ClosestPair {
     /**
      * Input data, maximum 10000.
      */
-    private Location[] array;
+    Location[] array;
     /**
      * Minimum point coordinate.
      */
diff --git a/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java b/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java
new file mode 100644
index 000000000000..38784228d68e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java
@@ -0,0 +1,75 @@
+package com.thealgorithms.divideandconquer;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import org.junit.jupiter.api.Test;
+
+public class ClosestPairTest {
+
+    @Test
+    public void testBuildLocation() {
+        ClosestPair cp = new ClosestPair(1);
+        ClosestPair.Location point = cp.buildLocation(3.0, 4.0);
+        assertNotNull(point);
+        assertEquals(3.0, point.x);
+        assertEquals(4.0, point.y);
+    }
+
+    @Test
+    public void testCreateLocation() {
+        ClosestPair cp = new ClosestPair(5);
+        ClosestPair.Location[] locations = cp.createLocation(5);
+        assertNotNull(locations);
+        assertEquals(5, locations.length);
+    }
+
+    @Test
+    public void testXPartition() {
+        ClosestPair cp = new ClosestPair(5);
+        ClosestPair.Location[] points = new ClosestPair.Location[5];
+        points[0] = cp.buildLocation(2.0, 3.0);
+        points[1] = cp.buildLocation(5.0, 1.0);
+        points[2] = cp.buildLocation(1.0, 6.0);
+        points[3] = cp.buildLocation(4.0, 7.0);
+        points[4] = cp.buildLocation(3.0, 2.0);
+
+        int pivotIndex = cp.xPartition(points, 0, 4);
+        assertEquals(2, pivotIndex);
+        assertEquals(2.0, points[0].x);
+        assertEquals(1.0, points[1].x);
+        assertEquals(3.0, points[2].x);
+        assertEquals(4.0, points[3].x);
+        assertEquals(5.0, points[4].x);
+    }
+
+    @Test
+    public void testYPartition() {
+        ClosestPair cp = new ClosestPair(5);
+        ClosestPair.Location[] points = new ClosestPair.Location[5];
+        points[0] = cp.buildLocation(2.0, 3.0);
+        points[1] = cp.buildLocation(5.0, 1.0);
+        points[2] = cp.buildLocation(1.0, 6.0);
+        points[3] = cp.buildLocation(4.0, 7.0);
+        points[4] = cp.buildLocation(3.0, 2.0);
+
+        int pivotIndex = cp.yPartition(points, 0, 4);
+        assertEquals(1, pivotIndex);
+        assertEquals(2.0, points[1].y);
+        assertEquals(3.0, points[4].y);
+        assertEquals(1.0, points[0].y);
+        assertEquals(6.0, points[2].y);
+        assertEquals(7.0, points[3].y);
+    }
+
+    @Test
+    public void testBruteForce() {
+        ClosestPair cp = new ClosestPair(2);
+        ClosestPair.Location loc1 = cp.buildLocation(1.0, 2.0);
+        ClosestPair.Location loc2 = cp.buildLocation(4.0, 6.0);
+
+        ClosestPair.Location[] locations = new ClosestPair.Location[] {loc1, loc2};
+        double result = cp.bruteForce(locations);
+        assertEquals(5.0, result, 0.01);
+    }
+}

From 7f57fc92b45e6a747614a48d4675e91d538d88a9 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 17:44:26 +0530
Subject: [PATCH 0437/1338] Improve comments, function & class documentation in
 `IndexOfRightMostSetBit.java` (#5579)

---
 .../IndexOfRightMostSetBit.java               | 22 +++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java b/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java
index b825916a8674..1b8962344ea7 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java
@@ -1,13 +1,27 @@
 package com.thealgorithms.bitmanipulation;
 
 /**
- * Find The Index Of Right Most SetBit
- * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
+ * Utility class for bit manipulation operations.
+ * This class provides methods to work with bitwise operations.
+ * Specifically, it includes a method to find the index of the rightmost set bit
+ * in an integer.
+ * This class is not meant to be instantiated.
+ *
+ * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
-
 public final class IndexOfRightMostSetBit {
+
     private IndexOfRightMostSetBit() {
     }
+
+    /**
+     * Finds the index of the rightmost set bit in the given integer.
+     * The index is zero-based, meaning the rightmost bit has an index of 0.
+     *
+     * @param n the integer to check for the rightmost set bit
+     * @return the index of the rightmost set bit; -1 if there are no set bits
+     *         (i.e., the input integer is 0)
+     */
     public static int indexOfRightMostSetBit(int n) {
         if (n == 0) {
             return -1; // No set bits
@@ -16,7 +30,7 @@ public static int indexOfRightMostSetBit(int n) {
         // Handle negative numbers by finding the two's complement
         if (n < 0) {
             n = -n;
-            n = n & (~n + 1); // Get the rightmost set bit in positive form
+            n = n & (~n + 1); // Isolate the rightmost set bit
         }
 
         int index = 0;

From 357fc6a2715eea9ef04822b967effee61fa91eb7 Mon Sep 17 00:00:00 2001
From: Prayas Kumar <71717433+prayas7102@users.noreply.github.com>
Date: Mon, 7 Oct 2024 17:48:25 +0530
Subject: [PATCH 0438/1338] Add LowestSetBit (#5567)

---
 .../bitmanipulation/LowestSetBit.java         | 34 ++++++++
 .../bitmanipulation/LowestSetBitTest.java     | 86 +++++++++++++++++++
 2 files changed, 120 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/LowestSetBit.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/LowestSetBit.java b/src/main/java/com/thealgorithms/bitmanipulation/LowestSetBit.java
new file mode 100644
index 000000000000..127b6fa2c0b1
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/LowestSetBit.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * Lowest Set Bit
+ * @author Prayas Kumar (https://github.com/prayas7102)
+ */
+
+public final class LowestSetBit {
+    // Private constructor to hide the default public one
+    private LowestSetBit() {
+    }
+    /**
+     * Isolates the lowest set bit of the given number. For example, if n = 18
+     * (binary: 10010), the result will be 2 (binary: 00010).
+     *
+     * @param n the number whose lowest set bit will be isolated
+     * @return the isolated lowest set bit of n
+     */
+    public static int isolateLowestSetBit(int n) {
+        // Isolate the lowest set bit using n & -n
+        return n & -n;
+    }
+    /**
+     * Clears the lowest set bit of the given number.
+     * For example, if n = 18 (binary: 10010), the result will be 16 (binary: 10000).
+     *
+     * @param n the number whose lowest set bit will be cleared
+     * @return the number after clearing its lowest set bit
+     */
+    public static int clearLowestSetBit(int n) {
+        // Clear the lowest set bit using n & (n - 1)
+        return n & (n - 1);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java b/src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java
new file mode 100644
index 000000000000..4c4d33640ad4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java
@@ -0,0 +1,86 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test case for Lowest Set Bit
+ * @author Prayas Kumar (https://github.com/prayas7102)
+ */
+
+public class LowestSetBitTest {
+
+    @Test
+    void testLowestSetBitWithPositiveNumber() {
+        // Test with a general positive number
+        assertEquals(2, LowestSetBit.isolateLowestSetBit(18)); // 18 in binary: 10010, lowest bit is 2
+    }
+
+    @Test
+    void testLowestSetBitWithZero() {
+        // Test with zero (edge case, no set bits)
+        assertEquals(0, LowestSetBit.isolateLowestSetBit(0)); // 0 has no set bits, result should be 0
+    }
+
+    @Test
+    void testLowestSetBitWithOne() {
+        // Test with number 1 (lowest set bit is 1 itself)
+        assertEquals(1, LowestSetBit.isolateLowestSetBit(1)); // 1 in binary: 0001, lowest bit is 1
+    }
+
+    @Test
+    void testLowestSetBitWithPowerOfTwo() {
+        // Test with a power of two (only one set bit)
+        assertEquals(16, LowestSetBit.isolateLowestSetBit(16)); // 16 in binary: 10000, lowest bit is 16
+    }
+
+    @Test
+    void testLowestSetBitWithAllBitsSet() {
+        // Test with a number with multiple set bits (like 7)
+        assertEquals(1, LowestSetBit.isolateLowestSetBit(7)); // 7 in binary: 111, lowest bit is 1
+    }
+
+    @Test
+    void testLowestSetBitWithNegativeNumber() {
+        // Test with a negative number (-1 in two's complement has all bits set)
+        assertEquals(1, LowestSetBit.isolateLowestSetBit(-1)); // -1 in two's complement is all 1s, lowest bit is 1
+    }
+
+    @Test
+    void testLowestSetBitWithLargeNumber() {
+        // Test with a large number
+        assertEquals(64, LowestSetBit.isolateLowestSetBit(448)); // 448 in binary: 111000000, lowest bit is 64
+    }
+
+    @Test
+    void testClearLowestSetBitFor18() {
+        // n = 18 (binary: 10010), expected result = 16 (binary: 10000)
+        assertEquals(16, LowestSetBit.clearLowestSetBit(18));
+    }
+
+    @Test
+    void testClearLowestSetBitFor10() {
+        // n = 10 (binary: 1010), expected result = 8 (binary: 1000)
+        assertEquals(8, LowestSetBit.clearLowestSetBit(10));
+    }
+
+    @Test
+    void testClearLowestSetBitFor7() {
+        // n = 7 (binary: 0111), expected result = 6 (binary: 0110)
+        assertEquals(6, LowestSetBit.clearLowestSetBit(7));
+    }
+
+    @Test
+    void testClearLowestSetBitFor0() {
+        // n = 0 (binary: 0000), no set bits to clear, expected result = 0
+        assertEquals(0, LowestSetBit.clearLowestSetBit(0));
+    }
+
+    @Test
+    void testClearLowestSetBitForNegativeNumber() {
+        // Test negative number to see how it behaves with two's complement
+        // n = -1 (binary: all 1s in two's complement), expected result = -2 (clearing lowest set bit)
+        assertEquals(-2, LowestSetBit.clearLowestSetBit(-1));
+    }
+}

From c45b2b81324b1e374a56ddcc089b82c4da2b8f29 Mon Sep 17 00:00:00 2001
From: ShikariSohan <52916464+ShikariSohan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 18:21:39 +0600
Subject: [PATCH 0439/1338] Add line clipping algorithms (#5580)

---
 .../lineclipping/CohenSutherland.java         | 133 ++++++++++++++++++
 .../lineclipping/LiangBarsky.java             |  93 ++++++++++++
 .../lineclipping/utils/Line.java              |  43 ++++++
 .../lineclipping/utils/Point.java             |  43 ++++++
 .../lineclipping/CohenSutherlandTest.java     |  81 +++++++++++
 .../lineclipping/LiangBarskyTest.java         |  65 +++++++++
 6 files changed, 458 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/lineclipping/CohenSutherland.java
 create mode 100644 src/main/java/com/thealgorithms/lineclipping/LiangBarsky.java
 create mode 100644 src/main/java/com/thealgorithms/lineclipping/utils/Line.java
 create mode 100644 src/main/java/com/thealgorithms/lineclipping/utils/Point.java
 create mode 100644 src/test/java/com/thealgorithms/lineclipping/CohenSutherlandTest.java
 create mode 100644 src/test/java/com/thealgorithms/lineclipping/LiangBarskyTest.java

diff --git a/src/main/java/com/thealgorithms/lineclipping/CohenSutherland.java b/src/main/java/com/thealgorithms/lineclipping/CohenSutherland.java
new file mode 100644
index 000000000000..6e8611b86332
--- /dev/null
+++ b/src/main/java/com/thealgorithms/lineclipping/CohenSutherland.java
@@ -0,0 +1,133 @@
+package com.thealgorithms.lineclipping;
+
+import com.thealgorithms.lineclipping.utils.Line;
+import com.thealgorithms.lineclipping.utils.Point;
+
+/**
+ * @author shikarisohan
+ * @since 10/4/24
+ * Cohen-Sutherland Line Clipping Algorithm
+ *
+ * This algorithm is used to clip a line segment to a rectangular window.
+ * It assigns a region code to each endpoint of the line segment, and
+ * then efficiently determines whether the line segment is fully inside,
+ * fully outside, or partially inside the window.
+ *
+ * Reference:
+ * https://en.wikipedia.org/wiki/Cohen%E2%80%93Sutherland_algorithm
+ *
+ * Clipping window boundaries are defined as (xMin, yMin) and (xMax, yMax).
+ * The algorithm computes the clipped line segment if it's partially or
+ * fully inside the clipping window.
+ */
+public class CohenSutherland {
+
+    // Region codes for the 9 regions
+    private static final int INSIDE = 0; // 0000
+    private static final int LEFT = 1; // 0001
+    private static final int RIGHT = 2; // 0010
+    private static final int BOTTOM = 4; // 0100
+    private static final int TOP = 8; // 1000
+
+    // Define the clipping window
+    double xMin;
+    double yMin;
+    double xMax;
+    double yMax;
+
+    public CohenSutherland(double xMin, double yMin, double xMax, double yMax) {
+        this.xMin = xMin;
+        this.yMin = yMin;
+        this.xMax = xMax;
+        this.yMax = yMax;
+    }
+
+    // Compute the region code for a point (x, y)
+    private int computeCode(double x, double y) {
+        int code = INSIDE;
+
+        if (x < xMin) // to the left of rectangle
+        {
+            code |= LEFT;
+        } else if (x > xMax) // to the right of rectangle
+        {
+            code |= RIGHT;
+        }
+        if (y < yMin) // below the rectangle
+        {
+            code |= BOTTOM;
+        } else if (y > yMax) // above the rectangle
+        {
+            code |= TOP;
+        }
+
+        return code;
+    }
+
+    // Cohen-Sutherland algorithm to return the clipped line
+    public Line cohenSutherlandClip(Line line) {
+        double x1 = line.start.x;
+        double y1 = line.start.y;
+        double x2 = line.end.x;
+        double y2 = line.end.y;
+
+        int code1 = computeCode(x1, y1);
+        int code2 = computeCode(x2, y2);
+        boolean accept = false;
+
+        while (true) {
+            if ((code1 == 0) && (code2 == 0)) {
+                // Both points are inside the rectangle
+                accept = true;
+                break;
+            } else if ((code1 & code2) != 0) {
+                // Both points are outside the rectangle in the same region
+                break;
+            } else {
+                // Some segment of the line is inside the rectangle
+                double x = 0;
+                double y = 0;
+
+                // Pick an endpoint that is outside the rectangle
+                int codeOut = (code1 != 0) ? code1 : code2;
+
+                // Find the intersection point using the line equation
+                if ((codeOut & TOP) != 0) {
+                    // Point is above the rectangle
+                    x = x1 + (x2 - x1) * (yMax - y1) / (y2 - y1);
+                    y = yMax;
+                } else if ((codeOut & BOTTOM) != 0) {
+                    // Point is below the rectangle
+                    x = x1 + (x2 - x1) * (yMin - y1) / (y2 - y1);
+                    y = yMin;
+                } else if ((codeOut & RIGHT) != 0) {
+                    // Point is to the right of the rectangle
+                    y = y1 + (y2 - y1) * (xMax - x1) / (x2 - x1);
+                    x = xMax;
+                } else if ((codeOut & LEFT) != 0) {
+                    // Point is to the left of the rectangle
+                    y = y1 + (y2 - y1) * (xMin - x1) / (x2 - x1);
+                    x = xMin;
+                }
+
+                // Replace the point outside the rectangle with the intersection point
+                if (codeOut == code1) {
+                    x1 = x;
+                    y1 = y;
+                    code1 = computeCode(x1, y1);
+                } else {
+                    x2 = x;
+                    y2 = y;
+                    code2 = computeCode(x2, y2);
+                }
+            }
+        }
+
+        if (accept) {
+            return new Line(new Point(x1, y1), new Point(x2, y2));
+        } else {
+
+            return null; // The line is fully rejected
+        }
+    }
+}
diff --git a/src/main/java/com/thealgorithms/lineclipping/LiangBarsky.java b/src/main/java/com/thealgorithms/lineclipping/LiangBarsky.java
new file mode 100644
index 000000000000..723e2bb2fbf9
--- /dev/null
+++ b/src/main/java/com/thealgorithms/lineclipping/LiangBarsky.java
@@ -0,0 +1,93 @@
+package com.thealgorithms.lineclipping;
+
+import com.thealgorithms.lineclipping.utils.Line;
+import com.thealgorithms.lineclipping.utils.Point;
+
+/**
+ * @author shikarisohan
+ * @since 10/5/24
+ *
+ *  * The Liang-Barsky line clipping algorithm is an efficient algorithm for
+ *  * line clipping against a rectangular window. It is based on the parametric
+ *  * equation of a line and checks the intersections of the line with the
+ *  * window boundaries. This algorithm calculates the intersection points,
+ *  * if any, and returns the clipped line that lies inside the window.
+ *  *
+ *  * Reference:
+ *  * https://en.wikipedia.org/wiki/Liang%E2%80%93Barsky_algorithm
+ *
+ * Clipping window boundaries are defined as (xMin, yMin) and (xMax, yMax).
+ * The algorithm computes the clipped line segment if it's partially or
+ * fully inside the clipping window.
+ */
+public class LiangBarsky {
+
+    // Define the clipping window
+    double xMin;
+    double xMax;
+    double yMin;
+    double yMax;
+
+    public LiangBarsky(double xMin, double yMin, double xMax, double yMax) {
+        this.xMin = xMin;
+        this.yMin = yMin;
+        this.xMax = xMax;
+        this.yMax = yMax;
+    }
+
+    // Liang-Barsky algorithm to return the clipped line
+    public Line liangBarskyClip(Line line) {
+        double dx = line.end.x - line.start.x;
+        double dy = line.end.y - line.start.y;
+
+        double[] p = {-dx, dx, -dy, dy};
+        double[] q = {line.start.x - xMin, xMax - line.start.x, line.start.y - yMin, yMax - line.start.y};
+
+        double[] resultT = clipLine(p, q);
+
+        if (resultT == null) {
+            return null; // Line is outside the clipping window
+        }
+
+        return calculateClippedLine(line, resultT[0], resultT[1], dx, dy);
+    }
+
+    // clip the line by adjusting t0 and t1 for each edge
+    private double[] clipLine(double[] p, double[] q) {
+        double t0 = 0.0;
+        double t1 = 1.0;
+
+        for (int i = 0; i < 4; i++) {
+            double t = q[i] / p[i];
+            if (p[i] == 0 && q[i] < 0) {
+                return null; // Line is outside the boundary
+            } else if (p[i] < 0) {
+                if (t > t1) {
+                    return null;
+                } // Line is outside
+                if (t > t0) {
+                    t0 = t;
+                } // Update t0
+            } else if (p[i] > 0) {
+                if (t < t0) {
+                    return null;
+                } // Line is outside
+                if (t < t1) {
+                    t1 = t;
+                } // Update t1
+            }
+        }
+
+        return new double[] {t0, t1}; // Return valid t0 and t1
+    }
+
+    // calculate the clipped line based on t0 and t1
+    private Line calculateClippedLine(Line line, double t0, double t1, double dx, double dy) {
+        double clippedX1 = line.start.x + t0 * dx;
+        double clippedY1 = line.start.y + t0 * dy;
+        double clippedX2 = line.start.x + t1 * dx;
+        double clippedY2 = line.start.y + t1 * dy;
+
+        return new Line(new Point(clippedX1, clippedY1), new Point(clippedX2, clippedY2));
+    }
+}
diff --git a/src/main/java/com/thealgorithms/lineclipping/utils/Line.java b/src/main/java/com/thealgorithms/lineclipping/utils/Line.java
new file mode 100644
index 000000000000..56cd52e3cdce
--- /dev/null
+++ b/src/main/java/com/thealgorithms/lineclipping/utils/Line.java
@@ -0,0 +1,43 @@
+package com.thealgorithms.lineclipping.utils;
+
+import java.util.Objects;
+
+/**
+ * @author moksedursohan
+ * @since 10/4/24
+ */
+public class Line {
+
+    public Point start;
+    public Point end;
+
+    public Line() {
+    }
+
+    public Line(Point start, Point end) {
+        this.start = start;
+        this.end = end;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (!(o instanceof Line line)) {
+            return false;
+        }
+
+        return Objects.equals(start, line.start) && Objects.equals(end, line.end);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(start, end);
+    }
+
+    @Override
+    public String toString() {
+        return "Line from " + start + " to " + end;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/lineclipping/utils/Point.java b/src/main/java/com/thealgorithms/lineclipping/utils/Point.java
new file mode 100644
index 000000000000..7ef58c783903
--- /dev/null
+++ b/src/main/java/com/thealgorithms/lineclipping/utils/Point.java
@@ -0,0 +1,43 @@
+package com.thealgorithms.lineclipping.utils;
+
+import java.util.Objects;
+
+/**
+ * @author moksedursohan
+ * @since 10/4/24
+ */
+public class Point {
+
+    public double x;
+    public double y;
+
+    public Point() {
+    }
+
+    public Point(double x, double y) {
+        this.x = x;
+        this.y = y;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (!(o instanceof Point point)) {
+            return false;
+        }
+
+        return Double.compare(x, point.x) == 0 && Double.compare(y, point.y) == 0;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(x, y);
+    }
+
+    @Override
+    public String toString() {
+        return "(" + x + ", " + y + ")";
+    }
+}
diff --git a/src/test/java/com/thealgorithms/lineclipping/CohenSutherlandTest.java b/src/test/java/com/thealgorithms/lineclipping/CohenSutherlandTest.java
new file mode 100644
index 000000000000..064f71a17c12
--- /dev/null
+++ b/src/test/java/com/thealgorithms/lineclipping/CohenSutherlandTest.java
@@ -0,0 +1,81 @@
+package com.thealgorithms.lineclipping;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import com.thealgorithms.lineclipping.utils.Line;
+import com.thealgorithms.lineclipping.utils.Point;
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author shikarisohan
+ * @since 10/4/24
+ */
+class CohenSutherlandTest {
+
+    // Define the clipping window (1.0, 1.0) to (10.0, 10.0)
+    CohenSutherland cs = new CohenSutherland(1.0, 1.0, 10.0, 10.0);
+
+    @Test
+    void testLineCompletelyInside() {
+        // Line fully inside the clipping window
+        Line line = new Line(new Point(2.0, 2.0), new Point(8.0, 8.0));
+        Line clippedLine = cs.cohenSutherlandClip(line);
+
+        assertNotNull(clippedLine, "Line should not be null.");
+        assertEquals(line, clippedLine, "Line inside the window should remain unchanged.");
+    }
+
+    @Test
+    void testLineCompletelyOutside() {
+        // Line completely outside and above the clipping window
+        Line line = new Line(new Point(11.0, 12.0), new Point(15.0, 18.0));
+        Line clippedLine = cs.cohenSutherlandClip(line);
+
+        assertNull(clippedLine, "Line should be null because it's completely outside.");
+    }
+
+    @Test
+    void testLinePartiallyInside() {
+        // Line partially inside the clipping window
+        Line line = new Line(new Point(5.0, 5.0), new Point(12.0, 12.0));
+        Line expectedClippedLine = new Line(new Point(5.0, 5.0), new Point(10.0, 10.0)); // Clipped at (10, 10)
+        Line clippedLine = cs.cohenSutherlandClip(line);
+
+        assertNotNull(clippedLine, "Line should not be null.");
+        assertEquals(expectedClippedLine, clippedLine, "Line should be clipped correctly.");
+    }
+
+    @Test
+    void testLineOnBoundary() {
+        // Line exactly on the boundary of the clipping window
+        Line line = new Line(new Point(1.0, 5.0), new Point(10.0, 5.0));
+        Line clippedLine = cs.cohenSutherlandClip(line);
+
+        assertNotNull(clippedLine, "Line should not be null.");
+        assertEquals(line, clippedLine, "Line on the boundary should remain unchanged.");
+    }
+
+    @Test
+    void testDiagonalLineThroughClippingWindow() {
+        // Diagonal line crossing from outside to outside through the window
+        Line line = new Line(new Point(0.0, 0.0), new Point(12.0, 12.0));
+        Line expectedClippedLine = new Line(new Point(1.0, 1.0), new Point(10.0, 10.0)); // Clipped at both boundaries
+        Line clippedLine = cs.cohenSutherlandClip(line);
+
+        assertNotNull(clippedLine, "Line should not be null.");
+        assertEquals(expectedClippedLine, clippedLine, "Diagonal line should be clipped correctly.");
+    }
+
+    @Test
+    void testVerticalLineClipping() {
+        // Vertical line crossing the top and bottom of the clipping window
+        Line line = new Line(new Point(5.0, 0.0), new Point(5.0, 12.0));
+        Line expectedClippedLine = new Line(new Point(5.0, 1.0), new Point(5.0, 10.0)); // Clipped at yMin and yMax
+        Line clippedLine = cs.cohenSutherlandClip(line);
+
+        assertNotNull(clippedLine, "Line should not be null.");
+        assertEquals(expectedClippedLine, clippedLine, "Vertical line should be clipped correctly.");
+    }
+}
diff --git a/src/test/java/com/thealgorithms/lineclipping/LiangBarskyTest.java b/src/test/java/com/thealgorithms/lineclipping/LiangBarskyTest.java
new file mode 100644
index 000000000000..1c48cd106572
--- /dev/null
+++ b/src/test/java/com/thealgorithms/lineclipping/LiangBarskyTest.java
@@ -0,0 +1,65 @@
+package com.thealgorithms.lineclipping;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import com.thealgorithms.lineclipping.utils.Line;
+import com.thealgorithms.lineclipping.utils.Point;
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author shikarisohan
+ * @since 10/5/24
+ */
+class LiangBarskyTest {
+
+    LiangBarsky lb = new LiangBarsky(1.0, 1.0, 10.0, 10.0);
+
+    @Test
+    void testLineCompletelyInside() {
+        Line line = new Line(new Point(2.0, 2.0), new Point(8.0, 8.0));
+        Line clippedLine = lb.liangBarskyClip(line);
+
+        assertNotNull(clippedLine, "Line should not be null.");
+        assertEquals(line, clippedLine, "Line inside the window should remain unchanged.");
+    }
+
+    @Test
+    void testLineCompletelyOutside() {
+        Line line = new Line(new Point(12.0, 12.0), new Point(15.0, 18.0));
+        Line clippedLine = lb.liangBarskyClip(line);
+
+        assertNull(clippedLine, "Line should be null because it's completely outside.");
+    }
+
+    @Test
+    void testLinePartiallyInside() {
+        Line line = new Line(new Point(5.0, 5.0), new Point(12.0, 12.0));
+        Line expectedClippedLine = new Line(new Point(5.0, 5.0), new Point(10.0, 10.0)); // Clipped at (10, 10)
+        Line clippedLine = lb.liangBarskyClip(line);
+
+        assertNotNull(clippedLine, "Line should not be null.");
+        assertEquals(expectedClippedLine, clippedLine, "Line should be clipped correctly.");
+    }
+
+    @Test
+    void testDiagonalLineThroughClippingWindow() {
+        Line line = new Line(new Point(0.0, 0.0), new Point(12.0, 12.0));
+        Line expectedClippedLine = new Line(new Point(1.0, 1.0), new Point(10.0, 10.0)); // Clipped at both boundaries
+        Line clippedLine = lb.liangBarskyClip(line);
+
+        assertNotNull(clippedLine, "Line should not be null.");
+        assertEquals(expectedClippedLine, clippedLine, "Diagonal line should be clipped correctly.");
+    }
+
+    @Test
+    void testVerticalLineClipping() {
+        Line line = new Line(new Point(5.0, 0.0), new Point(5.0, 12.0));
+        Line expectedClippedLine = new Line(new Point(5.0, 1.0), new Point(5.0, 10.0)); // Clipped at yMin and yMax
+        Line clippedLine = lb.liangBarskyClip(line);
+
+        assertNotNull(clippedLine, "Line should not be null.");
+        assertEquals(expectedClippedLine, clippedLine, "Vertical line should be clipped correctly.");
+    }
+}

From 2592a088e7759675224a6d6ba608aa9019b15bd4 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 17:56:21 +0530
Subject: [PATCH 0440/1338] Enhance readability, add comments & function docs
 to SkylineProblem.java (#5534)

---
 DIRECTORY.md                                  | 12 +++
 .../thealgorithms/others/SkylineProblem.java  | 99 +++++++++++--------
 .../others/SkylineProblemTest.java            | 86 ++++++++++++++++
 3 files changed, 154 insertions(+), 43 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/SkylineProblemTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6b44fa336a3a..0d34492fde9a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -27,6 +27,7 @@
             * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
             * [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
             * [IsPowerTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java)
+            * [LowestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/LowestSetBit.java)
             * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
             * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
@@ -280,6 +281,12 @@
             * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java)
           * io
             * [BufferedReader](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/io/BufferedReader.java)
+          * lineclipping
+            * [CohenSutherland](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/lineclipping/CohenSutherland.java)
+            * [LiangBarsky](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/lineclipping/LiangBarsky.java)
+            * utils
+              * [Line](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/lineclipping/utils/Line.java)
+              * [Point](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/lineclipping/utils/Point.java)
           * maths
             * [AbsoluteMax](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AbsoluteMax.java)
             * [AbsoluteMin](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AbsoluteMin.java)
@@ -615,6 +622,7 @@
             * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
             * [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
             * [IsPowerTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java)
+            * [LowestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java)
             * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
             * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
@@ -785,6 +793,9 @@
             * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java)
           * io
             * [BufferedReaderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/io/BufferedReaderTest.java)
+          * lineclipping
+            * [CohenSutherlandTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/lineclipping/CohenSutherlandTest.java)
+            * [LiangBarskyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/lineclipping/LiangBarskyTest.java)
           * maths
             * [AbsoluteMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java)
             * [AbsoluteMinTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java)
@@ -912,6 +923,7 @@
             * [QueueUsingTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java)
             * [RemoveDuplicateFromStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java)
             * [ReverseStackUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
+            * [SkylineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
diff --git a/src/main/java/com/thealgorithms/others/SkylineProblem.java b/src/main/java/com/thealgorithms/others/SkylineProblem.java
index ece398e70405..e84a5c5b585b 100644
--- a/src/main/java/com/thealgorithms/others/SkylineProblem.java
+++ b/src/main/java/com/thealgorithms/others/SkylineProblem.java
@@ -1,69 +1,68 @@
 package com.thealgorithms.others;
 
 import java.util.ArrayList;
-import java.util.Iterator;
-import java.util.Scanner;
 
+/**
+ * The {@code SkylineProblem} class is used to solve the skyline problem using a
+ * divide-and-conquer approach.
+ * It reads input for building data, processes it to find the skyline, and
+ * prints the skyline.
+ */
 public class SkylineProblem {
 
     Building[] building;
     int count;
 
-    public void run() {
-        Scanner sc = new Scanner(System.in);
-
-        int num = sc.nextInt();
-        this.building = new Building[num];
-
-        for (int i = 0; i < num; i++) {
-            String input = sc.next();
-            String[] data = input.split(",");
-            this.add(Integer.parseInt(data[0]), Integer.parseInt(data[1]), Integer.parseInt(data[2]));
-        }
-        this.print(this.findSkyline(0, num - 1));
-
-        sc.close();
-    }
-
+    /**
+     * Adds a building with the given left, height, and right values to the
+     * buildings list.
+     *
+     * @param left   The left x-coordinate of the building.
+     * @param height The height of the building.
+     * @param right  The right x-coordinate of the building.
+     */
     public void add(int left, int height, int right) {
         building[count++] = new Building(left, height, right);
     }
 
-    public void print(ArrayList<Skyline> skyline) {
-        Iterator<Skyline> it = skyline.iterator();
-
-        while (it.hasNext()) {
-            Skyline temp = it.next();
-            System.out.print(temp.coordinates + "," + temp.height);
-            if (it.hasNext()) {
-                System.out.print(",");
-            }
-        }
-    }
-
+    /**
+     * Computes the skyline for a range of buildings using the divide-and-conquer
+     * strategy.
+     *
+     * @param start The starting index of the buildings to process.
+     * @param end   The ending index of the buildings to process.
+     * @return A list of {@link Skyline} objects representing the computed skyline.
+     */
     public ArrayList<Skyline> findSkyline(int start, int end) {
+        // Base case: only one building, return its skyline.
         if (start == end) {
             ArrayList<Skyline> list = new ArrayList<>();
             list.add(new Skyline(building[start].left, building[start].height));
-            list.add(new Skyline(building[end].right, 0));
-
+            list.add(new Skyline(building[end].right, 0)); // Add the end of the building
             return list;
         }
 
         int mid = (start + end) / 2;
 
-        ArrayList<Skyline> sky1 = this.findSkyline(start, mid);
-        ArrayList<Skyline> sky2 = this.findSkyline(mid + 1, end);
-
-        return this.mergeSkyline(sky1, sky2);
+        ArrayList<Skyline> sky1 = this.findSkyline(start, mid); // Find the skyline of the left half
+        ArrayList<Skyline> sky2 = this.findSkyline(mid + 1, end); // Find the skyline of the right half
+        return this.mergeSkyline(sky1, sky2); // Merge the two skylines
     }
 
+    /**
+     * Merges two skylines (sky1 and sky2) into one combined skyline.
+     *
+     * @param sky1 The first skyline list.
+     * @param sky2 The second skyline list.
+     * @return A list of {@link Skyline} objects representing the merged skyline.
+     */
     public ArrayList<Skyline> mergeSkyline(ArrayList<Skyline> sky1, ArrayList<Skyline> sky2) {
         int currentH1 = 0;
         int currentH2 = 0;
         ArrayList<Skyline> skyline = new ArrayList<>();
         int maxH = 0;
 
+        // Merge the two skylines
         while (!sky1.isEmpty() && !sky2.isEmpty()) {
             if (sky1.get(0).coordinates < sky2.get(0).coordinates) {
                 int currentX = sky1.get(0).coordinates;
@@ -96,6 +95,7 @@ public ArrayList<Skyline> mergeSkyline(ArrayList<Skyline> sky1, ArrayList<Skylin
             }
         }
 
+        // Add any remaining points from sky1 or sky2
         while (!sky1.isEmpty()) {
             skyline.add(sky1.get(0));
             sky1.remove(0);
@@ -109,32 +109,45 @@ public ArrayList<Skyline> mergeSkyline(ArrayList<Skyline> sky1, ArrayList<Skylin
         return skyline;
     }
 
+    /**
+     * A class representing a point in the skyline with its x-coordinate and height.
+     */
     public class Skyline {
-
         public int coordinates;
         public int height;
 
+        /**
+         * Constructor for the {@code Skyline} class.
+         *
+         * @param coordinates The x-coordinate of the skyline point.
+         * @param height      The height of the skyline at the given coordinate.
+         */
         public Skyline(int coordinates, int height) {
             this.coordinates = coordinates;
             this.height = height;
         }
     }
 
+    /**
+     * A class representing a building with its left, height, and right
+     * x-coordinates.
+     */
     public class Building {
-
         public int left;
         public int height;
         public int right;
 
+        /**
+         * Constructor for the {@code Building} class.
+         *
+         * @param left   The left x-coordinate of the building.
+         * @param height The height of the building.
+         * @param right  The right x-coordinate of the building.
+         */
         public Building(int left, int height, int right) {
             this.left = left;
             this.height = height;
             this.right = right;
         }
     }
-
-    public static void main(String[] args) {
-        SkylineProblem skylineProblem = new SkylineProblem();
-        skylineProblem.run();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/others/SkylineProblemTest.java b/src/test/java/com/thealgorithms/others/SkylineProblemTest.java
new file mode 100644
index 000000000000..1ed5ced709c1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/SkylineProblemTest.java
@@ -0,0 +1,86 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import org.junit.jupiter.api.Test;
+
+public class SkylineProblemTest {
+
+    @Test
+    public void testSingleBuildingSkyline() {
+        SkylineProblem skylineProblem = new SkylineProblem();
+        skylineProblem.building = new SkylineProblem.Building[1];
+        skylineProblem.add(2, 10, 9);
+
+        ArrayList<SkylineProblem.Skyline> result = skylineProblem.findSkyline(0, 0);
+
+        assertEquals(2, result.get(0).coordinates);
+        assertEquals(10, result.get(0).height);
+        assertEquals(9, result.get(1).coordinates);
+        assertEquals(0, result.get(1).height);
+    }
+
+    @Test
+    public void testTwoBuildingsSkyline() {
+        SkylineProblem skylineProblem = new SkylineProblem();
+        skylineProblem.building = new SkylineProblem.Building[2];
+        skylineProblem.add(1, 11, 5);
+        skylineProblem.add(2, 6, 7);
+
+        ArrayList<SkylineProblem.Skyline> result = skylineProblem.findSkyline(0, 1);
+
+        // Expected skyline points: (1, 11), (5, 6), (7, 0)
+        assertEquals(1, result.get(0).coordinates);
+        assertEquals(11, result.get(0).height);
+        assertEquals(5, result.get(1).coordinates);
+        assertEquals(6, result.get(1).height);
+        assertEquals(7, result.get(2).coordinates);
+        assertEquals(0, result.get(2).height);
+    }
+
+    @Test
+    public void testMergeSkyline() {
+        SkylineProblem skylineProblem = new SkylineProblem();
+        ArrayList<SkylineProblem.Skyline> sky1 = new ArrayList<>();
+        ArrayList<SkylineProblem.Skyline> sky2 = new ArrayList<>();
+
+        sky1.add(skylineProblem.new Skyline(2, 10));
+        sky1.add(skylineProblem.new Skyline(9, 0));
+
+        sky2.add(skylineProblem.new Skyline(3, 15));
+        sky2.add(skylineProblem.new Skyline(7, 0));
+
+        ArrayList<SkylineProblem.Skyline> result = skylineProblem.mergeSkyline(sky1, sky2);
+
+        // Expected merged skyline: (2, 10), (3, 15), (7, 10), (9, 0)
+        assertEquals(2, result.get(0).coordinates);
+        assertEquals(10, result.get(0).height);
+        assertEquals(3, result.get(1).coordinates);
+        assertEquals(15, result.get(1).height);
+        assertEquals(7, result.get(2).coordinates);
+        assertEquals(10, result.get(2).height);
+        assertEquals(9, result.get(3).coordinates);
+        assertEquals(0, result.get(3).height);
+    }
+
+    @Test
+    public void testMultipleBuildingsSkyline() {
+        SkylineProblem skylineProblem = new SkylineProblem();
+        skylineProblem.building = new SkylineProblem.Building[3];
+        skylineProblem.add(1, 10, 5);
+        skylineProblem.add(2, 15, 7);
+        skylineProblem.add(3, 12, 9);
+
+        ArrayList<SkylineProblem.Skyline> result = skylineProblem.findSkyline(0, 2);
+
+        assertEquals(1, result.get(0).coordinates);
+        assertEquals(10, result.get(0).height);
+        assertEquals(2, result.get(1).coordinates);
+        assertEquals(15, result.get(1).height);
+        assertEquals(7, result.get(2).coordinates);
+        assertEquals(12, result.get(2).height);
+        assertEquals(9, result.get(3).coordinates);
+        assertEquals(0, result.get(3).height);
+    }
+}

From fa7d35745101851ed46bf9a3f813e495ef1f2841 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 18:36:59 +0530
Subject: [PATCH 0441/1338] Add tests, enhance class & function documentation
 for KnightsTour (#5591)

---
 DIRECTORY.md                                  |   1 +
 .../backtracking/KnightsTour.java             | 139 +++++++++---------
 .../backtracking/KnightsTourTest.java         |  59 ++++++++
 3 files changed, 133 insertions(+), 66 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/backtracking/KnightsTourTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0d34492fde9a..23544efba24c 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -607,6 +607,7 @@
             * [ArrayCombinationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java)
             * [CombinationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/CombinationTest.java)
             * [FloodFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/FloodFillTest.java)
+            * [KnightsTourTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/KnightsTourTest.java)
             * [MazeRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java)
             * [MColoringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/MColoringTest.java)
             * [NQueensTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/NQueensTest.java)
diff --git a/src/main/java/com/thealgorithms/backtracking/KnightsTour.java b/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
index 2287b39da385..2c2da659f3aa 100644
--- a/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
+++ b/src/main/java/com/thealgorithms/backtracking/KnightsTour.java
@@ -4,33 +4,26 @@
 import java.util.Comparator;
 import java.util.List;
 
-/*
-    * Problem Statement: -
-
-    Given a N*N board with the Knight placed on the first block of an empty board. Moving according
-   to the rules of chess knight must visit each square exactly once. Print the order of each cell in
-   which they are visited.
-
-    Example: -
-
-    Input : N = 8
-
-    Output:
-        0  59  38  33  30  17   8  63
-        37  34  31  60   9  62  29  16
-        58   1  36  39  32  27  18   7
-        35  48  41  26  61  10  15  28
-        42  57   2  49  40  23   6  19
-        47  50  45  54  25  20  11  14
-        56  43  52   3  22  13  24   5
-        51  46  55  44  53   4  21  12
-
+/**
+ * The KnightsTour class solves the Knight's Tour problem using backtracking.
+ *
+ * Problem Statement:
+ * Given an N*N board with a knight placed on the first block, the knight must
+ * move according to chess rules and visit each square on the board exactly once.
+ * The class outputs the sequence of moves for the knight.
+ *
+ * Example:
+ * Input: N = 8 (8x8 chess board)
+ * Output: The sequence of numbers representing the order in which the knight visits each square.
  */
 public final class KnightsTour {
     private KnightsTour() {
     }
 
+    // The size of the chess board (12x12 grid, with 2 extra rows/columns as a buffer around a 8x8 area)
     private static final int BASE = 12;
+
+    // Possible moves for a knight in chess
     private static final int[][] MOVES = {
         {1, -2},
         {2, -1},
@@ -40,36 +33,40 @@ private KnightsTour() {
         {-2, 1},
         {-2, -1},
         {-1, -2},
-    }; // Possible moves by knight on chess
-    private static int[][] grid; // chess grid
-    private static int total; // total squares in chess
+    };
+
+    // Chess grid representing the board
+    static int[][] grid;
+
+    // Total number of cells the knight needs to visit
+    static int total;
 
-    public static void main(String[] args) {
+    /**
+     * Resets the chess board to its initial state.
+     * Initializes the grid with boundary cells marked as -1 and internal cells as 0.
+     * Sets the total number of cells the knight needs to visit.
+     */
+    public static void resetBoard() {
         grid = new int[BASE][BASE];
         total = (BASE - 4) * (BASE - 4);
-
         for (int r = 0; r < BASE; r++) {
             for (int c = 0; c < BASE; c++) {
                 if (r < 2 || r > BASE - 3 || c < 2 || c > BASE - 3) {
-                    grid[r][c] = -1;
+                    grid[r][c] = -1; // Mark boundary cells
                 }
             }
         }
-
-        int row = 2 + (int) (Math.random() * (BASE - 4));
-        int col = 2 + (int) (Math.random() * (BASE - 4));
-
-        grid[row][col] = 1;
-
-        if (solve(row, col, 2)) {
-            printResult();
-        } else {
-            System.out.println("no result");
-        }
     }
 
-    // Return True when solvable
-    private static boolean solve(int row, int column, int count) {
+    /**
+     * Recursive method to solve the Knight's Tour problem.
+     *
+     * @param row   The current row of the knight
+     * @param column The current column of the knight
+     * @param count  The current move number
+     * @return True if a solution is found, False otherwise
+     */
+    static boolean solve(int row, int column, int count) {
         if (count > total) {
             return true;
         }
@@ -80,29 +77,37 @@ private static boolean solve(int row, int column, int count) {
             return false;
         }
 
+        // Sort neighbors by Warnsdorff's rule (fewest onward moves)
         neighbor.sort(Comparator.comparingInt(a -> a[2]));
 
         for (int[] nb : neighbor) {
-            row = nb[0];
-            column = nb[1];
-            grid[row][column] = count;
-            if (!orphanDetected(count, row, column) && solve(row, column, count + 1)) {
+            int nextRow = nb[0];
+            int nextCol = nb[1];
+            grid[nextRow][nextCol] = count;
+            if (!orphanDetected(count, nextRow, nextCol) && solve(nextRow, nextCol, count + 1)) {
                 return true;
             }
-            grid[row][column] = 0;
+            grid[nextRow][nextCol] = 0; // Backtrack
         }
 
         return false;
     }
 
-    // Returns List of neighbours
-    private static List<int[]> neighbors(int row, int column) {
+    /**
+     * Returns a list of valid neighboring cells where the knight can move.
+     *
+     * @param row   The current row of the knight
+     * @param column The current column of the knight
+     * @return A list of arrays representing valid moves, where each array contains:
+     *         {nextRow, nextCol, numberOfPossibleNextMoves}
+     */
+    static List<int[]> neighbors(int row, int column) {
         List<int[]> neighbour = new ArrayList<>();
 
         for (int[] m : MOVES) {
             int x = m[0];
             int y = m[1];
-            if (grid[row + y][column + x] == 0) {
+            if (row + y >= 0 && row + y < BASE && column + x >= 0 && column + x < BASE && grid[row + y][column + x] == 0) {
                 int num = countNeighbors(row + y, column + x);
                 neighbour.add(new int[] {row + y, column + x, num});
             }
@@ -110,19 +115,34 @@ private static List<int[]> neighbors(int row, int column) {
         return neighbour;
     }
 
-    // Returns the total count of neighbors
-    private static int countNeighbors(int row, int column) {
+    /**
+     * Counts the number of possible valid moves for a knight from a given position.
+     *
+     * @param row    The row of the current position
+     * @param column The column of the current position
+     * @return The number of valid neighboring moves
+     */
+    static int countNeighbors(int row, int column) {
         int num = 0;
         for (int[] m : MOVES) {
-            if (grid[row + m[1]][column + m[0]] == 0) {
+            int x = m[0];
+            int y = m[1];
+            if (row + y >= 0 && row + y < BASE && column + x >= 0 && column + x < BASE && grid[row + y][column + x] == 0) {
                 num++;
             }
         }
         return num;
     }
 
-    // Returns true if it is orphan
-    private static boolean orphanDetected(int count, int row, int column) {
+    /**
+     * Detects if moving to a given position will create an orphan (a position with no further valid moves).
+     *
+     * @param count   The current move number
+     * @param row     The row of the current position
+     * @param column  The column of the current position
+     * @return True if an orphan is detected, False otherwise
+     */
+    static boolean orphanDetected(int count, int row, int column) {
         if (count < total - 1) {
             List<int[]> neighbor = neighbors(row, column);
             for (int[] nb : neighbor) {
@@ -133,17 +153,4 @@ private static boolean orphanDetected(int count, int row, int column) {
         }
         return false;
     }
-
-    // Prints the result grid
-    private static void printResult() {
-        for (int[] row : grid) {
-            for (int i : row) {
-                if (i == -1) {
-                    continue;
-                }
-                System.out.printf("%2d ", i);
-            }
-            System.out.println();
-        }
-    }
 }
diff --git a/src/test/java/com/thealgorithms/backtracking/KnightsTourTest.java b/src/test/java/com/thealgorithms/backtracking/KnightsTourTest.java
new file mode 100644
index 000000000000..306dbf4c2ec7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/backtracking/KnightsTourTest.java
@@ -0,0 +1,59 @@
+package com.thealgorithms.backtracking;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class KnightsTourTest {
+
+    @BeforeEach
+    void setUp() {
+        // Call the reset method in the KnightsTour class
+        KnightsTour.resetBoard();
+    }
+
+    @Test
+    void testGridInitialization() {
+        for (int r = 0; r < 12; r++) {
+            for (int c = 0; c < 12; c++) {
+                if (r < 2 || r > 12 - 3 || c < 2 || c > 12 - 3) {
+                    assertEquals(-1, KnightsTour.grid[r][c], "Border cells should be -1");
+                } else {
+                    assertEquals(0, KnightsTour.grid[r][c], "Internal cells should be 0");
+                }
+            }
+        }
+    }
+
+    @Test
+    void testCountNeighbors() {
+        // Manually place a knight at (3, 3) and mark nearby cells to test counting
+        KnightsTour.grid[3][3] = 1; // Knight is here
+        KnightsTour.grid[5][4] = -1; // Block one potential move
+
+        int neighborCount = KnightsTour.countNeighbors(3, 3);
+        assertEquals(3, neighborCount, "Knight at (3, 3) should have 3 neighbors (one blocked)");
+
+        KnightsTour.grid[4][1] = -1; // Block another move
+        neighborCount = KnightsTour.countNeighbors(3, 3);
+        assertEquals(3, neighborCount, "Knight at (3, 3) should have 3 neighbors (two blocked)");
+    }
+
+    @Test
+    void testNeighbors() {
+        // Test the list of valid neighbors for a given cell (3, 3)
+        List<int[]> neighbors = KnightsTour.neighbors(3, 3);
+        assertEquals(4, neighbors.size(), "Knight at (3, 3) should have 8 valid neighbors");
+    }
+
+    @Test
+    void testSolveSuccessful() {
+        // Test if the solve method works for a successful knight's tour
+        KnightsTour.grid[2][2] = 1; // Start the knight at (2, 2)
+        boolean result = KnightsTour.solve(2, 2, 2);
+        assertTrue(result, "solve() should successfully complete a Knight's tour");
+    }
+}

From a2457bd1ff3cd0e55db1c4203a927b0c309b8bfe Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 18:47:27 +0530
Subject: [PATCH 0442/1338] Add tests for `IIRFilter.java`, fix bug in
 `setCoeffs` method (#5590)

---
 DIRECTORY.md                                  |  2 +
 .../thealgorithms/audiofilters/IIRFilter.java |  2 +-
 .../audiofilters/IIRFilterTest.java           | 83 +++++++++++++++++++
 3 files changed, 86 insertions(+), 1 deletion(-)
 create mode 100644 src/test/java/com/thealgorithms/audiofilters/IIRFilterTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 23544efba24c..19ebe5c4b8e0 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -602,6 +602,8 @@
     * java
       * com
         * thealgorithms
+          * audiofilters
+            * [IIRFilterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/audiofilters/IIRFilterTest.java)
           * backtracking
             * [AllPathsFromSourceToTargetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/AllPathsFromSourceToTargetTest.java)
             * [ArrayCombinationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java)
diff --git a/src/main/java/com/thealgorithms/audiofilters/IIRFilter.java b/src/main/java/com/thealgorithms/audiofilters/IIRFilter.java
index c211cd08a501..fbc095909541 100644
--- a/src/main/java/com/thealgorithms/audiofilters/IIRFilter.java
+++ b/src/main/java/com/thealgorithms/audiofilters/IIRFilter.java
@@ -58,7 +58,7 @@ public void setCoeffs(double[] aCoeffs, double[] bCoeffs) throws IllegalArgument
             throw new IllegalArgumentException("bCoeffs must be of size " + order + ", got " + bCoeffs.length);
         }
 
-        for (int i = 0; i <= order; i++) {
+        for (int i = 0; i < order; i++) {
             coeffsA[i] = aCoeffs[i];
             coeffsB[i] = bCoeffs[i];
         }
diff --git a/src/test/java/com/thealgorithms/audiofilters/IIRFilterTest.java b/src/test/java/com/thealgorithms/audiofilters/IIRFilterTest.java
new file mode 100644
index 000000000000..66d7d60c501b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/audiofilters/IIRFilterTest.java
@@ -0,0 +1,83 @@
+package com.thealgorithms.audiofilters;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class IIRFilterTest {
+
+    @Test
+    void testConstructorValidOrder() {
+        // Test a valid filter creation
+        IIRFilter filter = new IIRFilter(2);
+        assertNotNull(filter, "Filter should be instantiated correctly");
+    }
+
+    @Test
+    void testConstructorInvalidOrder() {
+        // Test an invalid filter creation (order <= 0)
+        assertThrows(IllegalArgumentException.class, () -> { new IIRFilter(0); }, "Order must be greater than zero");
+    }
+
+    @Test
+    void testSetCoeffsInvalidLengthA() {
+        IIRFilter filter = new IIRFilter(2);
+
+        // Invalid 'aCoeffs' length
+        double[] aCoeffs = {1.0}; // too short
+        double[] bCoeffs = {1.0, 0.5};
+        assertThrows(IllegalArgumentException.class, () -> { filter.setCoeffs(aCoeffs, bCoeffs); }, "aCoeffs must be of size 2");
+    }
+
+    @Test
+    void testSetCoeffsInvalidLengthB() {
+        IIRFilter filter = new IIRFilter(2);
+
+        // Invalid 'bCoeffs' length
+        double[] aCoeffs = {1.0, 0.5};
+        double[] bCoeffs = {1.0}; // too short
+        assertThrows(IllegalArgumentException.class, () -> { filter.setCoeffs(aCoeffs, bCoeffs); }, "bCoeffs must be of size 2");
+    }
+
+    @Test
+    void testSetCoeffsInvalidACoeffZero() {
+        IIRFilter filter = new IIRFilter(2);
+
+        // Invalid 'aCoeffs' where aCoeffs[0] == 0.0
+        double[] aCoeffs = {0.0, 0.5}; // aCoeffs[0] must not be zero
+        double[] bCoeffs = {1.0, 0.5};
+        assertThrows(IllegalArgumentException.class, () -> { filter.setCoeffs(aCoeffs, bCoeffs); }, "aCoeffs[0] must not be zero");
+    }
+
+    @Test
+    void testProcessWithNoCoeffsSet() {
+        // Test process method with default coefficients (sane defaults)
+        IIRFilter filter = new IIRFilter(2);
+        double inputSample = 0.5;
+        double result = filter.process(inputSample);
+
+        // Since default coeffsA[0] and coeffsB[0] are 1.0, expect output = input
+        assertEquals(inputSample, result, 1e-6, "Process should return the same value as input with default coefficients");
+    }
+
+    @Test
+    void testProcessWithCoeffsSet() {
+        // Test process method with set coefficients
+        IIRFilter filter = new IIRFilter(2);
+
+        double[] aCoeffs = {1.0, 0.5};
+        double[] bCoeffs = {1.0, 0.5};
+        filter.setCoeffs(aCoeffs, bCoeffs);
+
+        // Process a sample
+        double inputSample = 0.5;
+        double result = filter.process(inputSample);
+
+        // Expected output can be complex to calculate in advance;
+        // check if the method runs and returns a result within reasonable bounds
+        assertTrue(result >= -1.0 && result <= 1.0, "Processed result should be in the range [-1, 1]");
+    }
+}

From cacd23a2bde1da89393cab89cd519ffdf1af56db Mon Sep 17 00:00:00 2001
From: Muhammad Junaid Khalid <mjk22071998@gmail.com>
Date: Mon, 7 Oct 2024 19:17:04 +0500
Subject: [PATCH 0443/1338] Add binary addition (#5593)

---
 DIRECTORY.md                                  |  2 +
 .../greedyalgorithms/BinaryAddition.java      | 75 +++++++++++++++
 .../greedyalgorithms/BinaryAdditionTest.java  | 96 +++++++++++++++++++
 3 files changed, 173 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 19ebe5c4b8e0..2b4dc078c704 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -272,6 +272,7 @@
             * [GrahamScan](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/GrahamScan.java)
           * greedyalgorithms
             * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
+            * [BinaryAddition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java)
             * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java)
             * [DigitSeparation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java)
             * [FractionalKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
@@ -787,6 +788,7 @@
             * [GrahamScanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
           * greedyalgorithms
             * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
+            * [BinaryAdditionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java)
             * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java)
             * [DigitSeparationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java)
             * [FractionalKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java b/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java
new file mode 100644
index 000000000000..074c76b9f33f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java
@@ -0,0 +1,75 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.Collections;
+
+/**
+ * BinaryAddition class to perform binary addition of two binary strings.
+ */
+public class BinaryAddition {
+    /**
+     * Computes the sum of two binary characters and a carry.
+     * @param a First binary character ('0' or '1').
+     * @param b Second binary character ('0' or '1').
+     * @param carry The carry from the previous operation ('0' or '1').
+     * @return The sum as a binary character ('0' or '1').
+     */
+    public char sum(char a, char b, char carry) {
+        int count = 0;
+        if (a == '1') {
+            count++;
+        }
+        if (b == '1') {
+            count++;
+        }
+        if (carry == '1') {
+            count++;
+        }
+        return count % 2 == 0 ? '0' : '1';
+    }
+    /**
+     * Computes the carry for the next higher bit from two binary characters and a carry.
+     * @param a First binary character ('0' or '1').
+     * @param b Second binary character ('0' or '1').
+     * @param carry The carry from the previous operation ('0' or '1').
+     * @return The carry for the next bit ('0' or '1').
+     */
+    public char carry(char a, char b, char carry) {
+        int count = 0;
+        if (a == '1') {
+            count++;
+        }
+        if (b == '1') {
+            count++;
+        }
+        if (carry == '1') {
+            count++;
+        }
+        return count >= 2 ? '1' : '0';
+    }
+    /**
+     * Adds two binary strings and returns their sum as a binary string.
+     * @param a First binary string.
+     * @param b Second binary string.
+     * @return Binary string representing the sum of the two binary inputs.
+     */
+    public String addBinary(String a, String b) {
+        // Padding the shorter string with leading zeros
+        int maxLength = Math.max(a.length(), b.length());
+        a = String.join("", Collections.nCopies(maxLength - a.length(), "0")) + a;
+        b = String.join("", Collections.nCopies(maxLength - b.length(), "0")) + b;
+        StringBuilder result = new StringBuilder();
+        char carry = '0';
+        // Iterating over the binary strings from the least significant to the most significant bit
+        for (int i = maxLength - 1; i >= 0; i--) {
+            char sum = sum(a.charAt(i), b.charAt(i), carry);
+            carry = carry(a.charAt(i), b.charAt(i), carry);
+            result.append(sum);
+        }
+        // If there's a remaining carry, append it
+        if (carry == '1') {
+            result.append('1');
+        }
+        // Reverse the result as we constructed it from the least significant bit
+        return result.reverse().toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java
new file mode 100644
index 000000000000..893ca02ed8a3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java
@@ -0,0 +1,96 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class BinaryAdditionTest {
+
+    BinaryAddition binaryAddition = new BinaryAddition();
+
+    @Test
+    public void testEqualLengthNoCarry() {
+        String a = "1010";
+        String b = "1101";
+        String expected = "10111";
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+    }
+
+    @Test
+    public void testEqualLengthWithCarry() {
+        String a = "1111";
+        String b = "1111";
+        String expected = "11110";
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+    }
+
+    @Test
+    public void testDifferentLengths() {
+        String a = "101";
+        String b = "11";
+        String expected = "1000";
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+    }
+
+    @Test
+    public void testAllZeros() {
+        String a = "0";
+        String b = "0";
+        String expected = "0";
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+    }
+
+    @Test
+    public void testAllOnes() {
+        String a = "1111";
+        String b = "1111";
+        String expected = "11110";
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+    }
+
+    @Test
+    public void testOneZeroString() {
+        String a = "0";
+        String b = "10101";
+        String expected = "10101";
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+
+        // Test the other way around
+        a = "10101";
+        b = "0";
+        expected = "10101";
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+    }
+
+    @Test
+    public void testLargeBinaryNumbers() {
+        String a = "101010101010101010101010101010";
+        String b = "110110110110110110110110110110";
+        String expected = "1100001100001100001100001100000";
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+    }
+
+    @Test
+    public void testOneMuchLonger() {
+        String a = "1";
+        String b = "11111111";
+        String expected = "100000000";
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+    }
+
+    @Test
+    public void testEmptyStrings() {
+        String a = "";
+        String b = "";
+        String expected = ""; // Adding two empty strings should return 0
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+    }
+
+    @Test
+    public void testAlternatingBits() {
+        String a = "10101010";
+        String b = "01010101";
+        String expected = "11111111";
+        assertEquals(expected, binaryAddition.addBinary(a, b));
+    }
+}

From 93cfa86a97c9c13a7387f4e39388261eb1f90282 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 19:53:21 +0530
Subject: [PATCH 0444/1338] Add tests for `A5KeyStreamGenerator.java`, improve
 documentation (#5595)

---
 DIRECTORY.md                                  |  1 +
 .../ciphers/a5/A5KeyStreamGenerator.java      | 69 ++++++++++++++++++-
 .../ciphers/a5/A5KeyStreamGeneratorTest.java  | 60 ++++++++++++++++
 3 files changed, 128 insertions(+), 2 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 2b4dc078c704..6e9524120e9c 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -633,6 +633,7 @@
             * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
           * ciphers
             * a5
+              * [A5KeyStreamGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java)
               * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
             * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
             * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
diff --git a/src/main/java/com/thealgorithms/ciphers/a5/A5KeyStreamGenerator.java b/src/main/java/com/thealgorithms/ciphers/a5/A5KeyStreamGenerator.java
index 0b17a685bc57..ee837ef4241a 100644
--- a/src/main/java/com/thealgorithms/ciphers/a5/A5KeyStreamGenerator.java
+++ b/src/main/java/com/thealgorithms/ciphers/a5/A5KeyStreamGenerator.java
@@ -2,15 +2,39 @@
 
 import java.util.BitSet;
 
-// TODO: raise exceptions for improper use
+/**
+ * The A5KeyStreamGenerator class is responsible for generating key streams
+ * for the A5/1 encryption algorithm using a combination of Linear Feedback Shift Registers (LFSRs).
+ *
+ * <p>
+ * This class extends the CompositeLFSR and initializes a set of LFSRs with
+ * a session key and a frame counter to produce a pseudo-random key stream.
+ * </p>
+ *
+ * <p>
+ * Note: Proper exception handling for invalid usage is to be implemented.
+ * </p>
+ */
 public class A5KeyStreamGenerator extends CompositeLFSR {
 
     private BitSet initialFrameCounter;
     private BitSet frameCounter;
     private BitSet sessionKey;
     private static final int INITIAL_CLOCKING_CYCLES = 100;
-    private static final int KEY_STREAM_LENGTH = 228; // 28.5 bytes so we need to pad bytes or something
+    private static final int KEY_STREAM_LENGTH = 228;
 
+    /**
+     * Initializes the A5KeyStreamGenerator with the specified session key and frame counter.
+     *
+     * <p>
+     * This method sets up the internal state of the LFSRs using the provided
+     * session key and frame counter. It creates three LFSRs with specific
+     * configurations and initializes them.
+     * </p>
+     *
+     * @param sessionKey a BitSet representing the session key used for key stream generation.
+     * @param frameCounter a BitSet representing the frame counter that influences the key stream.
+     */
     @Override
     public void initialize(BitSet sessionKey, BitSet frameCounter) {
         this.sessionKey = sessionKey;
@@ -26,10 +50,26 @@ public void initialize(BitSet sessionKey, BitSet frameCounter) {
         registers.forEach(lfsr -> lfsr.initialize(sessionKey, frameCounter));
     }
 
+    /**
+     * Re-initializes the key stream generator with the original session key
+     * and frame counter. This method restores the generator to its initial
+     * state.
+     */
     public void reInitialize() {
         this.initialize(sessionKey, initialFrameCounter);
     }
 
+    /**
+     * Generates the next key stream of bits.
+     *
+     * <p>
+     * This method performs an initial set of clocking cycles and then retrieves
+     * a key stream of the specified length. After generation, it re-initializes
+     * the internal registers.
+     * </p>
+     *
+     * @return a BitSet containing the generated key stream bits.
+     */
     public BitSet getNextKeyStream() {
         for (int cycle = 1; cycle <= INITIAL_CLOCKING_CYCLES; ++cycle) {
             this.clock();
@@ -45,12 +85,37 @@ public BitSet getNextKeyStream() {
         return result;
     }
 
+    /**
+     * Re-initializes the registers for the LFSRs.
+     *
+     * <p>
+     * This method increments the frame counter and re-initializes each LFSR
+     * with the current session key and frame counter.
+     * </p>
+     */
     private void reInitializeRegisters() {
         incrementFrameCounter();
         registers.forEach(lfsr -> lfsr.initialize(sessionKey, frameCounter));
     }
 
+    /**
+     * Increments the current frame counter.
+     *
+     * <p>
+     * This method uses a utility function to increment the frame counter,
+     * which influences the key stream generation process.
+     * </p>
+     */
     private void incrementFrameCounter() {
         Utils.increment(frameCounter, FRAME_COUNTER_LENGTH);
     }
+
+    /**
+     * Retrieves the current frame counter.
+     *
+     * @return a BitSet representing the current state of the frame counter.
+     */
+    public BitSet getFrameCounter() {
+        return frameCounter;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java b/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java
new file mode 100644
index 000000000000..bb18d4500fc0
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.ciphers.a5;
+
+import static com.thealgorithms.ciphers.a5.A5KeyStreamGenerator.FRAME_COUNTER_LENGTH;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import java.util.BitSet;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class A5KeyStreamGeneratorTest {
+
+    private A5KeyStreamGenerator keyStreamGenerator;
+    private BitSet sessionKey;
+    private BitSet frameCounter;
+
+    @BeforeEach
+    void setUp() {
+        keyStreamGenerator = new A5KeyStreamGenerator();
+
+        // Initialize session key and frame counter for testing
+        sessionKey = BitSet.valueOf(new long[] {0b1010101010101010L}); // Example 16-bit key
+        frameCounter = BitSet.valueOf(new long[] {0b0000000000000001L}); // Example 16-bit frame counter
+        keyStreamGenerator.initialize(sessionKey, frameCounter);
+    }
+
+    @Test
+    void testInitialization() {
+        // Verify that the internal state is set up correctly
+        assertNotNull(keyStreamGenerator, "KeyStreamGenerator should be initialized");
+    }
+
+    @Test
+    void testIncrementFrameCounter() {
+        // Generate key stream to increment the frame counter
+        keyStreamGenerator.getNextKeyStream();
+
+        // The frame counter should have been incremented
+        BitSet incrementedFrameCounter = keyStreamGenerator.getFrameCounter();
+
+        // Check if the incremented frame counter is expected
+        BitSet expectedFrameCounter = (BitSet) frameCounter.clone();
+        Utils.increment(expectedFrameCounter, FRAME_COUNTER_LENGTH);
+
+        assertEquals(expectedFrameCounter, incrementedFrameCounter, "Frame counter should be incremented after generating key stream");
+    }
+
+    @Test
+    void testGetNextKeyStreamProducesDifferentOutputs() {
+        // Generate a key stream
+        BitSet firstKeyStream = keyStreamGenerator.getNextKeyStream();
+
+        // Generate another key stream
+        BitSet secondKeyStream = keyStreamGenerator.getNextKeyStream();
+
+        // Assert that consecutive key streams are different
+        assertNotEquals(firstKeyStream, secondKeyStream, "Consecutive key streams should be different");
+    }
+}

From 26e8ead4edebff4aabc90495ee3f4123d01f2325 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 19:58:01 +0530
Subject: [PATCH 0445/1338] Add tests for `A5Cipher.java`, improve class &
 function documentation (#5594)

---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/ciphers/a5/A5Cipher.java    | 39 ++++++++++++--
 .../ciphers/a5/A5CipherTest.java              | 51 +++++++++++++++++++
 3 files changed, 88 insertions(+), 3 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6e9524120e9c..90b26ae98797 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -633,6 +633,7 @@
             * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
           * ciphers
             * a5
+              * [A5CipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java)
               * [A5KeyStreamGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java)
               * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
             * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
diff --git a/src/main/java/com/thealgorithms/ciphers/a5/A5Cipher.java b/src/main/java/com/thealgorithms/ciphers/a5/A5Cipher.java
index b7d36db5c809..cc2e9105229a 100644
--- a/src/main/java/com/thealgorithms/ciphers/a5/A5Cipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/a5/A5Cipher.java
@@ -2,17 +2,43 @@
 
 import java.util.BitSet;
 
-// https://en.wikipedia.org/wiki/A5/1
+/**
+ * The A5Cipher class implements the A5/1 stream cipher, which is a widely used
+ * encryption algorithm, particularly in mobile communications.
+ *
+ * This implementation uses a key stream generator to produce a stream of bits
+ * that are XORed with the plaintext bits to produce the ciphertext.
+ *
+ * <p>
+ * For more details about the A5/1 algorithm, refer to
+ * <a href="https://en.wikipedia.org/wiki/A5/1">Wikipedia</a>.
+ * </p>
+ */
 public class A5Cipher {
 
     private final A5KeyStreamGenerator keyStreamGenerator;
-    private static final int KEY_STREAM_LENGTH = 228; // 28.5 bytes so we need to pad bytes or something
-
+    private static final int KEY_STREAM_LENGTH = 228; // Length of the key stream in bits (28.5 bytes)
+
+    /**
+     * Constructs an A5Cipher instance with the specified session key and frame counter.
+     *
+     * @param sessionKey a BitSet representing the session key used for encryption.
+     * @param frameCounter a BitSet representing the frame counter that helps in key stream generation.
+     */
     public A5Cipher(BitSet sessionKey, BitSet frameCounter) {
         keyStreamGenerator = new A5KeyStreamGenerator();
         keyStreamGenerator.initialize(sessionKey, frameCounter);
     }
 
+    /**
+     * Encrypts the given plaintext bits using the A5/1 cipher algorithm.
+     *
+     * This method generates a key stream and XORs it with the provided plaintext
+     * bits to produce the ciphertext.
+     *
+     * @param plainTextBits a BitSet representing the plaintext bits to be encrypted.
+     * @return a BitSet containing the encrypted ciphertext bits.
+     */
     public BitSet encrypt(BitSet plainTextBits) {
         // create a copy
         var result = new BitSet(KEY_STREAM_LENGTH);
@@ -24,6 +50,13 @@ public BitSet encrypt(BitSet plainTextBits) {
         return result;
     }
 
+    /**
+     * Resets the internal counter of the key stream generator.
+     *
+     * This method can be called to re-initialize the state of the key stream
+     * generator, allowing for new key streams to be generated for subsequent
+     * encryptions.
+     */
     public void resetCounter() {
         keyStreamGenerator.reInitialize();
     }
diff --git a/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java b/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java
new file mode 100644
index 000000000000..aa725b644a86
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java
@@ -0,0 +1,51 @@
+package com.thealgorithms.ciphers.a5;
+
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+import java.util.BitSet;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class A5CipherTest {
+
+    private A5Cipher a5Cipher;
+    private BitSet sessionKey;
+    private BitSet frameCounter;
+
+    @BeforeEach
+    void setUp() {
+        // Initialize the session key and frame counter
+        sessionKey = BitSet.valueOf(new long[] {0b1010101010101010L});
+        frameCounter = BitSet.valueOf(new long[] {0b0000000000000001L});
+        a5Cipher = new A5Cipher(sessionKey, frameCounter);
+    }
+
+    @Test
+    void testEncryptWithValidInput() {
+        BitSet plainText = BitSet.valueOf(new long[] {0b1100110011001100L}); // Example plaintext
+        BitSet encrypted = a5Cipher.encrypt(plainText);
+
+        // The expected result depends on the key stream generated.
+        // In a real test, you would replace this with the actual expected result.
+        // For now, we will just assert that the encrypted result is not equal to the plaintext.
+        assertNotEquals(plainText, encrypted, "Encrypted output should not equal plaintext");
+    }
+
+    @Test
+    void testEncryptAllOnesInput() {
+        BitSet plainText = BitSet.valueOf(new long[] {0b1111111111111111L}); // All ones
+        BitSet encrypted = a5Cipher.encrypt(plainText);
+
+        // Similar to testEncryptWithValidInput, ensure that output isn't the same as input
+        assertNotEquals(plainText, encrypted, "Encrypted output should not equal plaintext of all ones");
+    }
+
+    @Test
+    void testEncryptAllZerosInput() {
+        BitSet plainText = new BitSet(); // All zeros
+        BitSet encrypted = a5Cipher.encrypt(plainText);
+
+        // Check that the encrypted output is not the same
+        assertNotEquals(plainText, encrypted, "Encrypted output should not equal plaintext of all zeros");
+    }
+}

From 99d7f80a61cfdb01b4eb8d93d2df4f1862d55bf0 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 20:30:57 +0530
Subject: [PATCH 0446/1338] Add Junit tests for `AESEncryption.java` (#5597)

---
 DIRECTORY.md                                  |  1 +
 .../ciphers/AESEncryptionTest.java            | 62 +++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 90b26ae98797..4b98173a4e85 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -636,6 +636,7 @@
               * [A5CipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java)
               * [A5KeyStreamGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java)
               * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
+            * [AESEncryptionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java)
             * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
             * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
             * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
diff --git a/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java b/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java
new file mode 100644
index 000000000000..2f0831e35064
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java
@@ -0,0 +1,62 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import javax.crypto.SecretKey;
+import org.junit.jupiter.api.Test;
+
+public class AESEncryptionTest {
+
+    @Test
+    public void testGetSecretEncryptionKey() throws Exception {
+        SecretKey key = AESEncryption.getSecretEncryptionKey();
+        assertNotNull(key, "Secret key should not be null");
+        assertEquals(128, key.getEncoded().length * 8, "Key size should be 128 bits");
+    }
+
+    @Test
+    public void testEncryptText() throws Exception {
+        String plainText = "Hello World";
+        SecretKey secKey = AESEncryption.getSecretEncryptionKey();
+        byte[] cipherText = AESEncryption.encryptText(plainText, secKey);
+
+        assertNotNull(cipherText, "Ciphertext should not be null");
+        assertTrue(cipherText.length > 0, "Ciphertext should not be empty");
+    }
+
+    @Test
+    public void testDecryptText() throws Exception {
+        String plainText = "Hello World";
+        SecretKey secKey = AESEncryption.getSecretEncryptionKey();
+        byte[] cipherText = AESEncryption.encryptText(plainText, secKey);
+
+        // Decrypt the ciphertext
+        String decryptedText = AESEncryption.decryptText(cipherText, secKey);
+
+        assertNotNull(decryptedText, "Decrypted text should not be null");
+        assertEquals(plainText, decryptedText, "Decrypted text should match the original plain text");
+    }
+
+    @Test
+    public void testEncryptDecrypt() throws Exception {
+        String plainText = "Hello AES!";
+        SecretKey secKey = AESEncryption.getSecretEncryptionKey();
+
+        // Encrypt the plaintext
+        byte[] cipherText = AESEncryption.encryptText(plainText, secKey);
+
+        // Decrypt the ciphertext
+        String decryptedText = AESEncryption.decryptText(cipherText, secKey);
+
+        assertEquals(plainText, decryptedText, "Decrypted text should match the original plain text");
+    }
+
+    @Test
+    public void testBytesToHex() {
+        byte[] bytes = new byte[] {0, 1, 15, 16, (byte) 255}; // Test with diverse byte values
+        String hex = AESEncryption.bytesToHex(bytes);
+        assertEquals("00010F10FF", hex, "Hex representation should match the expected value");
+    }
+}

From f80850b2447365d518ad0f8117360700a82dda59 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 20:38:55 +0530
Subject: [PATCH 0447/1338] Add Junit tests for `AffineCipher.java`, improve
 documentation (#5598)

---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/ciphers/AffineCipher.java   | 51 +++++++++++++++----
 .../ciphers/AffineCipherTest.java             | 39 ++++++++++++++
 3 files changed, 80 insertions(+), 11 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 4b98173a4e85..d8b1045b5c35 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -637,6 +637,7 @@
               * [A5KeyStreamGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java)
               * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
             * [AESEncryptionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java)
+            * [AffineCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java)
             * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
             * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
             * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
diff --git a/src/main/java/com/thealgorithms/ciphers/AffineCipher.java b/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
index bcf3a5b0167b..636323b63646 100644
--- a/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
@@ -1,5 +1,23 @@
 package com.thealgorithms.ciphers;
 
+/**
+ * The AffineCipher class implements the Affine cipher, a type of monoalphabetic substitution cipher.
+ * It encrypts and decrypts messages using a linear transformation defined by the formula:
+ *
+ *     E(x) = (a * x + b) mod m
+ *     D(y) = a^-1 * (y - b) mod m
+ *
+ * where:
+ * - E(x) is the encrypted character,
+ * - D(y) is the decrypted character,
+ * - a is the multiplicative key (must be coprime to m),
+ * - b is the additive key,
+ * - x is the index of the plaintext character,
+ * - y is the index of the ciphertext character,
+ * - m is the size of the alphabet (26 for the English alphabet).
+ *
+ * The class provides methods for encrypting and decrypting messages, as well as a main method to demonstrate its usage.
+ */
 final class AffineCipher {
     private AffineCipher() {
     }
@@ -8,16 +26,22 @@ private AffineCipher() {
     static int a = 17;
     static int b = 20;
 
+    /**
+     * Encrypts a message using the Affine cipher.
+     *
+     * @param msg the plaintext message as a character array
+     * @return the encrypted ciphertext
+     */
     static String encryptMessage(char[] msg) {
-        /// Cipher Text initially empty
+        // Cipher Text initially empty
         String cipher = "";
         for (int i = 0; i < msg.length; i++) {
             // Avoid space to be encrypted
-            /* applying encryption formula ( a x + b ) mod m
+            /* applying encryption formula ( a * x + b ) mod m
             {here x is msg[i] and m is 26} and added 'A' to
-            bring it in range of ascii alphabet[ 65-90 | A-Z ] */
+            bring it in the range of ASCII alphabet [65-90 | A-Z] */
             if (msg[i] != ' ') {
-                cipher = cipher + (char) ((((a * (msg[i] - 'A')) + b) % 26) + 'A');
+                cipher += (char) ((((a * (msg[i] - 'A')) + b) % 26) + 'A');
             } else { // else simply append space character
                 cipher += msg[i];
             }
@@ -25,28 +49,33 @@ static String encryptMessage(char[] msg) {
         return cipher;
     }
 
+    /**
+     * Decrypts a ciphertext using the Affine cipher.
+     *
+     * @param cipher the ciphertext to decrypt
+     * @return the decrypted plaintext message
+     */
     static String decryptCipher(String cipher) {
         String msg = "";
         int aInv = 0;
-        int flag = 0;
+        int flag;
 
-        // Find a^-1 (the multiplicative inverse of a
-        // in the group of integers modulo m.)
+        // Find a^-1 (the multiplicative inverse of a in the group of integers modulo m.)
         for (int i = 0; i < 26; i++) {
             flag = (a * i) % 26;
 
-            // Check if (a*i)%26 == 1,
+            // Check if (a * i) % 26 == 1,
             // then i will be the multiplicative inverse of a
             if (flag == 1) {
                 aInv = i;
             }
         }
         for (int i = 0; i < cipher.length(); i++) {
-            /*Applying decryption formula a^-1 ( x - b ) mod m
+            /* Applying decryption formula a^-1 * (x - b) mod m
             {here x is cipher[i] and m is 26} and added 'A'
-            to bring it in range of ASCII alphabet[ 65-90 | A-Z ] */
+            to bring it in the range of ASCII alphabet [65-90 | A-Z] */
             if (cipher.charAt(i) != ' ') {
-                msg = msg + (char) (((aInv * ((cipher.charAt(i) + 'A' - b)) % 26)) + 'A');
+                msg += (char) (((aInv * ((cipher.charAt(i) - 'A') - b + 26)) % 26) + 'A');
             } else { // else simply append space character
                 msg += cipher.charAt(i);
             }
diff --git a/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java b/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java
new file mode 100644
index 000000000000..b1a2ce593a8e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java
@@ -0,0 +1,39 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class AffineCipherTest {
+
+    @Test
+    public void testEncryptMessage() {
+        String plaintext = "AFFINE CIPHER";
+        char[] msg = plaintext.toCharArray();
+        String expectedCiphertext = "UBBAHK CAPJKX"; // Expected ciphertext after encryption
+
+        String actualCiphertext = AffineCipher.encryptMessage(msg);
+        assertEquals(expectedCiphertext, actualCiphertext, "The encryption result should match the expected ciphertext.");
+    }
+
+    @Test
+    public void testEncryptDecrypt() {
+        String plaintext = "HELLO WORLD";
+        char[] msg = plaintext.toCharArray();
+
+        String ciphertext = AffineCipher.encryptMessage(msg);
+        String decryptedText = AffineCipher.decryptCipher(ciphertext);
+
+        assertEquals(plaintext, decryptedText, "Decrypted text should match the original plaintext.");
+    }
+
+    @Test
+    public void testSpacesHandledInEncryption() {
+        String plaintext = "HELLO WORLD";
+        char[] msg = plaintext.toCharArray();
+        String expectedCiphertext = "JKZZY EYXZT";
+
+        String actualCiphertext = AffineCipher.encryptMessage(msg);
+        assertEquals(expectedCiphertext, actualCiphertext, "The encryption should handle spaces correctly.");
+    }
+}

From 25dc55e4ae784af32f2aa53e95439106a3befd05 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 20:41:56 +0530
Subject: [PATCH 0448/1338] Add Junit tests for
 `ColumnarTranspositionCipher.java` (#5599)

---
 DIRECTORY.md                                  |  1 +
 .../ciphers/ColumnarTranspositionCipher.java  | 20 --------
 .../ColumnarTranspositionCipherTest.java      | 47 +++++++++++++++++++
 3 files changed, 48 insertions(+), 20 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index d8b1045b5c35..02a24678b83f 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -641,6 +641,7 @@
             * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
             * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
             * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
+            * [ColumnarTranspositionCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java)
             * [DESTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DESTest.java)
             * [HillCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/HillCipherTest.java)
             * [PlayfairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java)
diff --git a/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java b/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java
index e59cfb12d816..d7e64a12ebfd 100644
--- a/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java
@@ -184,24 +184,4 @@ private static void abecedariumBuilder(int value) {
         }
         abecedarium = t.toString();
     }
-
-    private static void showTable() {
-        for (Object[] table1 : table) {
-            for (Object item : table1) {
-                System.out.print(item + " ");
-            }
-            System.out.println();
-        }
-    }
-
-    public static void main(String[] args) {
-        String keywordForExample = "asd215";
-        String wordBeingEncrypted = "This is a test of the Columnar Transposition Cipher";
-        System.out.println("### Example of Columnar Transposition Cipher ###\n");
-        System.out.println("Word being encryped ->>> " + wordBeingEncrypted);
-        System.out.println("Word encrypted ->>> " + ColumnarTranspositionCipher.encrpyter(wordBeingEncrypted, keywordForExample));
-        System.out.println("Word decryped ->>> " + ColumnarTranspositionCipher.decrypter());
-        System.out.println("\n### Encrypted Table ###");
-        showTable();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java b/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java
new file mode 100644
index 000000000000..0d306a6623db
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java
@@ -0,0 +1,47 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class ColumnarTranspositionCipherTest {
+    private String keyword;
+    private String plaintext;
+
+    @BeforeEach
+    public void setUp() {
+        keyword = "keyword";
+        plaintext = "This is a test message for Columnar Transposition Cipher";
+    }
+
+    @Test
+    public void testEncryption() {
+        String encryptedText = ColumnarTranspositionCipher.encrpyter(plaintext, keyword);
+        assertNotNull(encryptedText, "The encrypted text should not be null.");
+        assertFalse(encryptedText.isEmpty(), "The encrypted text should not be empty.");
+        // Check if the encrypted text is different from the plaintext
+        assertNotEquals(plaintext, encryptedText, "The encrypted text should be different from the plaintext.");
+    }
+
+    @Test
+    public void testDecryption() {
+        String encryptedText = ColumnarTranspositionCipher.encrpyter(plaintext, keyword);
+        String decryptedText = ColumnarTranspositionCipher.decrypter();
+
+        assertEquals(plaintext.replaceAll(" ", ""), decryptedText.replaceAll(" ", ""), "The decrypted text should match the original plaintext, ignoring spaces.");
+        assertEquals(encryptedText, ColumnarTranspositionCipher.encrpyter(plaintext, keyword), "The encrypted text should be the same when encrypted again.");
+    }
+
+    @Test
+    public void testLongPlainText() {
+        String longText = "This is a significantly longer piece of text to test the encryption and decryption capabilities of the Columnar Transposition Cipher. It should handle long strings gracefully.";
+        String encryptedText = ColumnarTranspositionCipher.encrpyter(longText, keyword);
+        String decryptedText = ColumnarTranspositionCipher.decrypter();
+        assertEquals(longText.replaceAll(" ", ""), decryptedText.replaceAll(" ", ""), "The decrypted text should match the original long plaintext, ignoring spaces.");
+        assertEquals(encryptedText, ColumnarTranspositionCipher.encrpyter(longText, keyword), "The encrypted text should be the same when encrypted again.");
+    }
+}

From d422bf5983aa7c715af17cdf2592ed53316cd2c6 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 20:45:50 +0530
Subject: [PATCH 0449/1338] Add tests for `AffineConverter.java` (#5602)

---
 DIRECTORY.md                                  |  1 +
 .../conversions/AffineConverterTest.java      | 55 +++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/conversions/AffineConverterTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 02a24678b83f..7e5d0d3de9ba 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -651,6 +651,7 @@
             * [VigenereTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/VigenereTest.java)
             * [XORCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/XORCipherTest.java)
           * conversions
+            * [AffineConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/AffineConverterTest.java)
             * [AnyBaseToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java)
             * [BinaryToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java)
             * [BinaryToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java)
diff --git a/src/test/java/com/thealgorithms/conversions/AffineConverterTest.java b/src/test/java/com/thealgorithms/conversions/AffineConverterTest.java
new file mode 100644
index 000000000000..2705955f68f6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/AffineConverterTest.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class AffineConverterTest {
+
+    private AffineConverter converter;
+
+    @BeforeEach
+    void setUp() {
+        converter = new AffineConverter(2.0, 3.0);
+    }
+
+    @Test
+    void testConstructor() {
+        assertEquals(3.0, converter.convert(0.0), "Expected value when input is 0.0");
+        assertEquals(5.0, converter.convert(1.0), "Expected value when input is 1.0");
+        assertEquals(7.0, converter.convert(2.0), "Expected value when input is 2.0");
+    }
+
+    @Test
+    void testConvert() {
+        assertEquals(3.0, converter.convert(0.0), "Conversion at 0.0 should equal the intercept");
+        assertEquals(7.0, converter.convert(2.0), "2.0 should convert to 7.0");
+        assertEquals(11.0, converter.convert(4.0), "4.0 should convert to 11.0");
+    }
+
+    @Test
+    void testInvert() {
+        AffineConverter inverted = converter.invert();
+        assertEquals(0.0, inverted.convert(3.0), "Inverted converter should return 0.0 for input 3.0");
+        assertEquals(1.0, inverted.convert(5.0), "Inverted converter should return 1.0 for input 5.0");
+        assertEquals(2.0, inverted.convert(7.0), "Inverted converter should return 2.0 for input 7.0");
+    }
+
+    @Test
+    void testInvertWithZeroSlope() {
+        AffineConverter zeroSlopeConverter = new AffineConverter(0.0, 3.0);
+        assertThrows(AssertionError.class, zeroSlopeConverter::invert, "Invert should throw assertion error when slope is zero");
+    }
+
+    @Test
+    void testCompose() {
+        AffineConverter otherConverter = new AffineConverter(1.0, 2.0);
+        AffineConverter composed = converter.compose(otherConverter);
+
+        assertEquals(7.0, composed.convert(0.0), "Expected composed conversion at 0.0");
+        assertEquals(9.0, composed.convert(1.0), "Expected composed conversion at 1.0");
+        assertEquals(11.0, composed.convert(2.0), "Expected composed conversion at 2.0");
+    }
+}

From 62144f61af289cc94cec380d680b8865726c459a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 21:55:48 +0530
Subject: [PATCH 0450/1338] Add tests for `AStar.java`, enhance documentation
 (#5603)

---
 DIRECTORY.md                                  |   1 +
 .../datastructures/graphs/AStar.java          | 144 ++++++------------
 .../datastructures/graphs/AStarTest.java      |  46 ++++++
 3 files changed, 92 insertions(+), 99 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7e5d0d3de9ba..87922528abda 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -694,6 +694,7 @@
             * dynamicarray
               * [DynamicArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java)
             * graphs
+              * [AStarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java)
               * [BipartiteGraphDFSTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java)
               * [BoruvkaAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
               * [DijkstraAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java b/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java
index 54fb5fba5c1b..460c05e04403 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java
@@ -1,25 +1,26 @@
-/*
-        Time Complexity = O(E), where E is equal to the number of edges
- */
 package com.thealgorithms.datastructures.graphs;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Comparator;
 import java.util.List;
 import java.util.PriorityQueue;
 
+/**
+ * AStar class implements the A* pathfinding algorithm to find the shortest path in a graph.
+ * The graph is represented using an adjacency list, and the algorithm uses a heuristic to estimate
+ * the cost to reach the destination node.
+ * Time Complexity = O(E), where E is equal to the number of edges
+ */
 public final class AStar {
     private AStar() {
     }
 
-    private static class Graph {
-
-        // Graph's structure can be changed only applying changes to this class.
-
+    /**
+     * Represents a graph using an adjacency list.
+     */
+    static class Graph {
         private ArrayList<ArrayList<Edge>> graph;
 
-        // Initialise ArrayLists in Constructor
         Graph(int size) {
             this.graph = new ArrayList<>();
             for (int i = 0; i < size; i++) {
@@ -31,15 +32,17 @@ private ArrayList<Edge> getNeighbours(int from) {
             return this.graph.get(from);
         }
 
-        // Graph is bidirectional, for just one direction remove second instruction of this method.
+        // Add a bidirectional edge to the graph
         private void addEdge(Edge edge) {
             this.graph.get(edge.getFrom()).add(new Edge(edge.getFrom(), edge.getTo(), edge.getWeight()));
             this.graph.get(edge.getTo()).add(new Edge(edge.getTo(), edge.getFrom(), edge.getWeight()));
         }
     }
 
+    /**
+     * Represents an edge in the graph with a start node, end node, and weight.
+     */
     private static class Edge {
-
         private int from;
         private int to;
         private int weight;
@@ -63,12 +66,13 @@ public int getWeight() {
         }
     }
 
-    // class to iterate during the algorithm execution, and also used to return the solution.
-    private static class PathAndDistance {
-
-        private int distance; // distance advanced so far.
-        private ArrayList<Integer> path; // list of visited nodes in this path.
-        private int estimated; // heuristic value associated to the last node od the path (current node).
+    /**
+     * Contains information about the path and its total distance.
+     */
+    static class PathAndDistance {
+        private int distance; // total distance from the start node
+        private ArrayList<Integer> path; // list of nodes in the path
+        private int estimated; // heuristic estimate for reaching the destination
 
         PathAndDistance(int distance, ArrayList<Integer> path, int estimated) {
             this.distance = distance;
@@ -87,112 +91,54 @@ public ArrayList<Integer> getPath() {
         public int getEstimated() {
             return estimated;
         }
-
-        private void printSolution() {
-            if (this.path != null) {
-                System.out.println("Optimal path: " + this.path + ", distance: " + this.distance);
-            } else {
-                System.out.println("There is no path available to connect the points");
-            }
-        }
     }
 
-    private static void initializeGraph(Graph graph, ArrayList<Integer> data) {
+    // Initializes the graph with edges defined in the input data
+    static void initializeGraph(Graph graph, ArrayList<Integer> data) {
         for (int i = 0; i < data.size(); i += 4) {
             graph.addEdge(new Edge(data.get(i), data.get(i + 1), data.get(i + 2)));
         }
-        /*
-    .x. node
-    (y) cost
-    - or | or / bidirectional connection
-
-                          ( 98)- .7. -(86)- .4.
-                            |
-                    ( 85)- .17. -(142)- .18. -(92)- .8. -(87)- .11.
-                      |
-                     . 1. -------------------- (160)
-                      |  \                       |
-                    (211) \                     .6.
-                      |    \                     |
-                     . 5.  (101)-.13. -(138)   (115)
-                      |           |     |     /
-                    ( 99)       ( 97)   |    /
-                      |           |     |   /
-        .12. -(151)- .15. -(80)- .14.   |  /
-         |            |           |     | /
-       ( 71)        (140)       (146)- .2. -(120)
-         |            |                       |
-        .19. -( 75)- . 0.        .10. -(75)- .3.
-                      |            |
-                    (118)        ( 70)
-                      |            |
-                     .16. -(111)- .9.
-         */
-    }
-
-    public static void main(String[] args) {
-        // heuristic function optimistic values
-        int[] heuristic = {
-            366,
-            0,
-            160,
-            242,
-            161,
-            178,
-            77,
-            151,
-            226,
-            244,
-            241,
-            234,
-            380,
-            98,
-            193,
-            253,
-            329,
-            80,
-            199,
-            374,
-        };
-
-        Graph graph = new Graph(20);
-        ArrayList<Integer> graphData = new ArrayList<>(Arrays.asList(0, 19, 75, null, 0, 15, 140, null, 0, 16, 118, null, 19, 12, 71, null, 12, 15, 151, null, 16, 9, 111, null, 9, 10, 70, null, 10, 3, 75, null, 3, 2, 120, null, 2, 14, 146, null, 2, 13, 138, null, 2, 6, 115, null, 15, 14, 80, null,
-            15, 5, 99, null, 14, 13, 97, null, 5, 1, 211, null, 13, 1, 101, null, 6, 1, 160, null, 1, 17, 85, null, 17, 7, 98, null, 7, 4, 86, null, 17, 18, 142, null, 18, 8, 92, null, 8, 11, 87));
-        initializeGraph(graph, graphData);
-
-        PathAndDistance solution = aStar(3, 1, graph, heuristic);
-        solution.printSolution();
     }
 
+    /**
+     * Implements the A* pathfinding algorithm to find the shortest path from a start node to a destination node.
+     *
+     * @param from     the starting node
+     * @param to       the destination node
+     * @param graph    the graph representation of the problem
+     * @param heuristic the heuristic estimates for each node
+     * @return a PathAndDistance object containing the shortest path and its distance
+     */
     public static PathAndDistance aStar(int from, int to, Graph graph, int[] heuristic) {
-        // nodes are prioritised by the less value of the current distance of their paths, and the
-        // estimated value
-        // given by the heuristic function to reach the destination point from the current point.
+        // PriorityQueue to explore nodes based on their distance and estimated cost to reach the destination
         PriorityQueue<PathAndDistance> queue = new PriorityQueue<>(Comparator.comparingInt(a -> (a.getDistance() + a.getEstimated())));
 
-        // dummy data to start the algorithm from the beginning point
-        queue.add(new PathAndDistance(0, new ArrayList<>(List.of(from)), 0));
+        // Start with the initial node
+        queue.add(new PathAndDistance(0, new ArrayList<>(List.of(from)), heuristic[from]));
 
         boolean solutionFound = false;
         PathAndDistance currentData = new PathAndDistance(-1, null, -1);
+
         while (!queue.isEmpty() && !solutionFound) {
-            currentData = queue.poll(); // first in the queue, best node so keep exploring.
-            int currentPosition = currentData.getPath().get(currentData.getPath().size() - 1); // current node.
+            currentData = queue.poll(); // get the best node from the queue
+            int currentPosition = currentData.getPath().get(currentData.getPath().size() - 1); // current node
+
+            // Check if the destination has been reached
             if (currentPosition == to) {
                 solutionFound = true;
             } else {
                 for (Edge edge : graph.getNeighbours(currentPosition)) {
-                    if (!currentData.getPath().contains(edge.getTo())) { // Avoid Cycles
+                    // Avoid cycles by checking if the next node is already in the path
+                    if (!currentData.getPath().contains(edge.getTo())) {
                         ArrayList<Integer> updatedPath = new ArrayList<>(currentData.getPath());
-                        updatedPath.add(edge.getTo()); // Add the new node to the path, update the distance,
-                        // and the heuristic function value associated to that path.
+                        updatedPath.add(edge.getTo());
+
+                        // Update the distance and heuristic for the new path
                         queue.add(new PathAndDistance(currentData.getDistance() + edge.getWeight(), updatedPath, heuristic[edge.getTo()]));
                     }
                 }
             }
         }
         return (solutionFound) ? currentData : new PathAndDistance(-1, null, -1);
-        // Out of while loop, if there is a solution, the current Data stores the optimal path, and
-        // its distance
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java
new file mode 100644
index 000000000000..dce5a6ed4b69
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java
@@ -0,0 +1,46 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class AStarTest {
+
+    private AStar.Graph graph;
+    private int[] heuristic;
+
+    @BeforeEach
+    public void setUp() {
+        // Initialize graph and heuristic values for testing
+        graph = new AStar.Graph(5);
+        ArrayList<Integer> graphData = new ArrayList<>(Arrays.asList(0, 1, 1, null, 0, 2, 2, null, 1, 3, 1, null, 2, 3, 1, null, 3, 4, 1, null));
+        AStar.initializeGraph(graph, graphData);
+
+        heuristic = new int[] {5, 4, 3, 2, 0}; // Heuristic values for each node
+    }
+
+    @Test
+    public void testAStarFindsPath() {
+        AStar.PathAndDistance result = AStar.aStar(0, 4, graph, heuristic);
+        assertEquals(3, result.getDistance(), "Expected distance from 0 to 4 is 3");
+        assertEquals(Arrays.asList(0, 1, 3, 4), result.getPath(), "Expected path from 0 to 4");
+    }
+
+    @Test
+    public void testAStarPathNotFound() {
+        AStar.PathAndDistance result = AStar.aStar(0, 5, graph, heuristic); // Node 5 does not exist
+        assertEquals(-1, result.getDistance(), "Expected distance when path not found is -1");
+        assertNull(result.getPath(), "Expected path should be null when no path exists");
+    }
+
+    @Test
+    public void testAStarSameNode() {
+        AStar.PathAndDistance result = AStar.aStar(0, 0, graph, heuristic);
+        assertEquals(0, result.getDistance(), "Expected distance from 0 to 0 is 0");
+        assertEquals(Arrays.asList(0), result.getPath(), "Expected path should only contain the start node");
+    }
+}

From 676d451aa605a9442cdda85badbd0877816d6cf7 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 7 Oct 2024 22:17:29 +0530
Subject: [PATCH 0451/1338] Add class documentation, improve comments in
 `MazeRecursion.java` (#5576)

---
 .../backtracking/MazeRecursion.java           | 205 ++++++++----------
 .../backtracking/MazeRecursionTest.java       |  34 ++-
 2 files changed, 103 insertions(+), 136 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java b/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java
index f7eae01e449a..8247172e7ee0 100644
--- a/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java
+++ b/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java
@@ -1,152 +1,125 @@
 package com.thealgorithms.backtracking;
 
+/**
+ * This class contains methods to solve a maze using recursive backtracking.
+ * The maze is represented as a 2D array where walls, paths, and visited/dead
+ * ends are marked with different integers.
+ *
+ * The goal is to find a path from a starting position to the target position
+ * (map[6][5]) while navigating through the maze.
+ */
 public final class MazeRecursion {
+
     private MazeRecursion() {
     }
 
-    public static void mazeRecursion() {
-        // First create a 2 dimensions array to mimic a maze map
-        int[][] map = new int[8][7];
-        int[][] map2 = new int[8][7];
-
-        // We use 1 to indicate wall
-        // Set the ceiling and floor to 1
-        for (int i = 0; i < 7; i++) {
-            map[0][i] = 1;
-            map[7][i] = 1;
-        }
-
-        // Then we set the left and right wall to 1
-        for (int i = 0; i < 8; i++) {
-            map[i][0] = 1;
-            map[i][6] = 1;
-        }
-
-        // Now we have created a maze with its wall initialized
-
-        // Here we set the obstacle
-        map[3][1] = 1;
-        map[3][2] = 1;
-
-        // Print the current map
-        System.out.println("The condition of the map： ");
-        for (int i = 0; i < 8; i++) {
-            for (int j = 0; j < 7; j++) {
-                System.out.print(map[i][j] + " ");
-            }
-            System.out.println();
-        }
-
-        // clone another map for setWay2 method
-        for (int i = 0; i < map.length; i++) {
-            System.arraycopy(map[i], 0, map2[i], 0, map[i].length);
-        }
-
-        // By using recursive backtracking to let your ball(target) find its way in the
-        // maze
-        // The first parameter is the map
-        // Second parameter is x coordinate of your target
-        // Third parameter is the y coordinate of your target
-        setWay(map, 1, 1);
-        setWay2(map2, 1, 1);
-
-        // Print out the new map1, with the ball footprint
-        System.out.println("After the ball goes through the map1，show the current map1 condition");
-        for (int i = 0; i < 8; i++) {
-            for (int j = 0; j < 7; j++) {
-                System.out.print(map[i][j] + " ");
-            }
-            System.out.println();
+    /**
+     * This method solves the maze using the "down -> right -> up -> left"
+     * movement strategy.
+     *
+     * @param map The 2D array representing the maze (walls, paths, etc.)
+     * @return The solved maze with paths marked, or null if no solution exists.
+     */
+    public static int[][] solveMazeUsingFirstStrategy(int[][] map) {
+        if (setWay(map, 1, 1)) {
+            return map;
         }
+        return null;
+    }
 
-        // Print out the new map2, with the ball footprint
-        System.out.println("After the ball goes through the map2，show the current map2 condition");
-        for (int i = 0; i < 8; i++) {
-            for (int j = 0; j < 7; j++) {
-                System.out.print(map2[i][j] + " ");
-            }
-            System.out.println();
+    /**
+     * This method solves the maze using the "up -> right -> down -> left"
+     * movement strategy.
+     *
+     * @param map The 2D array representing the maze (walls, paths, etc.)
+     * @return The solved maze with paths marked, or null if no solution exists.
+     */
+    public static int[][] solveMazeUsingSecondStrategy(int[][] map) {
+        if (setWay2(map, 1, 1)) {
+            return map;
         }
+        return null;
     }
 
     /**
-     * Using recursive path finding to help the ball find its way in the maze
-     * Description：
-     * 1. map (means the maze)
-     * 2. i, j (means the initial coordinate of the ball in the maze)
-     * 3. if the ball can reach the end of maze, that is position of map[6][5],
-     * means the we have found a path for the ball
-     * 4. Additional Information： 0 in the map[i][j] means the ball has not gone
-     * through this position, 1 means the wall, 2 means the path is feasible, 3
-     * means the ball has gone through the path but this path is dead end
-     * 5. We will need strategy for the ball to pass through the maze for example:
-     * Down -> Right -> Up -> Left, if the path doesn't work, then backtrack
+     * Attempts to find a path through the maze using a "down -> right -> up -> left"
+     * movement strategy. The path is marked with '2' for valid paths and '3' for dead ends.
      *
-     * @author OngLipWei
-     * @version Jun 23, 2021 11:36:14 AM
-     * @param map The maze
-     * @param i   x coordinate of your ball(target)
-     * @param j   y coordinate of your ball(target)
-     * @return If we did find a path for the ball，return true，else false
+     * @param map The 2D array representing the maze (walls, paths, etc.)
+     * @param i   The current x-coordinate of the ball (row index)
+     * @param j   The current y-coordinate of the ball (column index)
+     * @return True if a path is found to (6,5), otherwise false
      */
-    public static boolean setWay(int[][] map, int i, int j) {
-        if (map[6][5] == 2) { // means the ball find its path, ending condition
+    private static boolean setWay(int[][] map, int i, int j) {
+        if (map[6][5] == 2) {
             return true;
         }
-        if (map[i][j] == 0) { // if the ball haven't gone through this point
-            // then the ball follows the move strategy : down -> right -> up -> left
-            map[i][j] = 2; // we assume that this path is feasible first, set the current point to 2
-                           // first。
-            if (setWay(map, i + 1, j)) { // go down
+
+        // If the current position is unvisited (0), explore it
+        if (map[i][j] == 0) {
+            // Mark the current position as '2'
+            map[i][j] = 2;
+
+            // Move down
+            if (setWay(map, i + 1, j)) {
                 return true;
-            } else if (setWay(map, i, j + 1)) { // go right
+            }
+            // Move right
+            else if (setWay(map, i, j + 1)) {
                 return true;
-            } else if (setWay(map, i - 1, j)) { // go up
+            }
+            // Move up
+            else if (setWay(map, i - 1, j)) {
                 return true;
-            } else if (setWay(map, i, j - 1)) { // go left
+            }
+            // Move left
+            else if (setWay(map, i, j - 1)) {
                 return true;
-            } else {
-                // means that the current point is the dead end, the ball cannot proceed, set
-                // the current point to 3 and return false, the backtracking will start, it will
-                // go to the previous step and check for feasible path again
-                map[i][j] = 3;
-                return false;
             }
-        } else { // if the map[i][j] != 0 , it will probably be 1,2,3, return false because the
-            // ball cannot hit the wall, cannot go to the path that has gone though before,
-            // and cannot head to deadened.
+
+            map[i][j] = 3; // Mark as dead end (3) if no direction worked
             return false;
         }
+        return false;
     }
 
-    // Here is another move strategy for the ball: up->right->down->left
-    public static boolean setWay2(int[][] map, int i, int j) {
-        if (map[6][5] == 2) { // means the ball find its path, ending condition
+    /**
+     * Attempts to find a path through the maze using an alternative movement
+     * strategy "up -> right -> down -> left".
+     *
+     * @param map The 2D array representing the maze (walls, paths, etc.)
+     * @param i   The current x-coordinate of the ball (row index)
+     * @param j   The current y-coordinate of the ball (column index)
+     * @return True if a path is found to (6,5), otherwise false
+     */
+    private static boolean setWay2(int[][] map, int i, int j) {
+        if (map[6][5] == 2) {
             return true;
         }
-        if (map[i][j] == 0) { // if the ball haven't gone through this point
-            // then the ball follows the move strategy : up->right->down->left
-            map[i][j] = 2; // we assume that this path is feasible first, set the current point to 2
-                           // first。
-            if (setWay2(map, i - 1, j)) { // go up
+
+        if (map[i][j] == 0) {
+            map[i][j] = 2;
+
+            // Move up
+            if (setWay2(map, i - 1, j)) {
                 return true;
-            } else if (setWay2(map, i, j + 1)) { // go right
+            }
+            // Move right
+            else if (setWay2(map, i, j + 1)) {
                 return true;
-            } else if (setWay2(map, i + 1, j)) { // go down
+            }
+            // Move down
+            else if (setWay2(map, i + 1, j)) {
                 return true;
-            } else if (setWay2(map, i, j - 1)) { // go left
+            }
+            // Move left
+            else if (setWay2(map, i, j - 1)) {
                 return true;
-            } else {
-                // means that the current point is the dead end, the ball cannot proceed, set
-                // the current point to 3 and return false, the backtracking will start, it will
-                // go to the previous step and check for feasible path again
-                map[i][j] = 3;
-                return false;
             }
-        } else { // if the map[i][j] != 0 , it will probably be 1,2,3, return false because the
-            // ball cannot hit the wall, cannot go to the path that has gone through before,
-            // and cannot head to deadend.
+
+            map[i][j] = 3; // Mark as dead end (3) if no direction worked
             return false;
         }
+        return false;
     }
 }
diff --git a/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java b/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java
index edaca14af067..b8e77fb38bad 100644
--- a/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java
@@ -11,41 +11,35 @@
 public class MazeRecursionTest {
 
     @Test
-    public void testMaze() {
-        // First create a 2 dimensions array to mimic a maze map
+    public void testSolveMazeUsingFirstAndSecondStrategy() {
         int[][] map = new int[8][7];
         int[][] map2 = new int[8][7];
 
-        // We use 1 to indicate wall
+        // We use 1 to indicate walls
         // Set the ceiling and floor to 1
         for (int i = 0; i < 7; i++) {
             map[0][i] = 1;
             map[7][i] = 1;
         }
-
-        // Then we set the left and right wall to 1
+        // Set the left and right wall to 1
         for (int i = 0; i < 8; i++) {
             map[i][0] = 1;
             map[i][6] = 1;
         }
-
-        // Now we have created a maze with its wall initialized
-
-        // Here we set the obstacle
+        // Set obstacles
         map[3][1] = 1;
         map[3][2] = 1;
 
-        // clone another map for setWay2 method
+        // Clone the original map for the second pathfinding strategy
         for (int i = 0; i < map.length; i++) {
-            for (int j = 0; j < map[i].length; j++) {
-                map2[i][j] = map[i][j];
-            }
+            System.arraycopy(map[i], 0, map2[i], 0, map[i].length);
         }
 
-        MazeRecursion.setWay(map, 1, 1);
-        MazeRecursion.setWay2(map2, 1, 1);
-
-        int[][] expectedMap = new int[][] {
+        // Solve the maze using the first strategy
+        int[][] solvedMap1 = MazeRecursion.solveMazeUsingFirstStrategy(map);
+        // Solve the maze using the second strategy
+        int[][] solvedMap2 = MazeRecursion.solveMazeUsingSecondStrategy(map2);
+        int[][] expectedMap1 = new int[][] {
             {1, 1, 1, 1, 1, 1, 1},
             {1, 2, 0, 0, 0, 0, 1},
             {1, 2, 2, 2, 0, 0, 1},
@@ -55,7 +49,6 @@ public void testMaze() {
             {1, 0, 0, 2, 2, 2, 1},
             {1, 1, 1, 1, 1, 1, 1},
         };
-
         int[][] expectedMap2 = new int[][] {
             {1, 1, 1, 1, 1, 1, 1},
             {1, 2, 2, 2, 2, 2, 1},
@@ -67,7 +60,8 @@ public void testMaze() {
             {1, 1, 1, 1, 1, 1, 1},
         };
 
-        assertArrayEquals(map, expectedMap);
-        assertArrayEquals(map2, expectedMap2);
+        // Assert the results
+        assertArrayEquals(expectedMap1, solvedMap1);
+        assertArrayEquals(expectedMap2, solvedMap2);
     }
 }

From 732f7c8458669fca84f9800c0d0864a5634eca6a Mon Sep 17 00:00:00 2001
From: Prayas Kumar <71717433+prayas7102@users.noreply.github.com>
Date: Mon, 7 Oct 2024 23:00:46 +0530
Subject: [PATCH 0452/1338] Add BM25 Inverted Index Search Algorithm (#5615)

---
 .../searches/BM25InvertedIndex.java           | 220 ++++++++++++++++++
 .../searches/BM25InvertedIndexTest.java       |  93 ++++++++
 2 files changed, 313 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java
 create mode 100644 src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java

diff --git a/src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java b/src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java
new file mode 100644
index 000000000000..1cfd2bbad8e4
--- /dev/null
+++ b/src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java
@@ -0,0 +1,220 @@
+package com.thealgorithms.searches;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Inverted Index implementation with BM25 Scoring for movie search.
+ * This class supports adding movie documents and searching for terms
+ * within those documents using the BM25 algorithm.
+ * @author Prayas Kumar (https://github.com/prayas7102)
+ */
+
+class Movie {
+    int docId; // Unique identifier for the movie
+    String name; // Movie name
+    double imdbRating; // IMDb rating of the movie
+    int releaseYear; // Year the movie was released
+    String content; // Full text content (could be the description or script)
+
+    /**
+     * Constructor for the Movie class.
+     * @param docId Unique identifier for the movie.
+     * @param name Name of the movie.
+     * @param imdbRating IMDb rating of the movie.
+     * @param releaseYear Release year of the movie.
+     * @param content Content or description of the movie.
+     */
+    Movie(int docId, String name, double imdbRating, int releaseYear, String content) {
+        this.docId = docId;
+        this.name = name;
+        this.imdbRating = imdbRating;
+        this.releaseYear = releaseYear;
+        this.content = content;
+    }
+
+    /**
+     * Get all the words from the movie's name and content.
+     * Converts the name and content to lowercase and splits on non-word characters.
+     * @return Array of words from the movie name and content.
+     */
+    public String[] getWords() {
+        return (name + " " + content).toLowerCase().split("\\W+");
+    }
+
+    @Override
+    public String toString() {
+        return "Movie{"
+            + "docId=" + docId + ", name='" + name + '\'' + ", imdbRating=" + imdbRating + ", releaseYear=" + releaseYear + '}';
+    }
+}
+
+class SearchResult {
+    int docId; // Unique identifier of the movie document
+    double relevanceScore; // Relevance score based on the BM25 algorithm
+
+    /**
+     * Constructor for SearchResult class.
+     * @param docId Document ID (movie) for this search result.
+     * @param relevanceScore The relevance score based on BM25 scoring.
+     */
+    SearchResult(int docId, double relevanceScore) {
+        this.docId = docId;
+        this.relevanceScore = relevanceScore;
+    }
+
+    public int getDocId() {
+        return docId;
+    }
+
+    @Override
+    public String toString() {
+        return "SearchResult{"
+            + "docId=" + docId + ", relevanceScore=" + relevanceScore + '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        SearchResult that = (SearchResult) o;
+        return docId == that.docId && Double.compare(that.relevanceScore, relevanceScore) == 0;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(docId, relevanceScore);
+    }
+
+    public double getRelevanceScore() {
+        return this.relevanceScore;
+    }
+}
+
+public final class BM25InvertedIndex {
+    private Map<String, Map<Integer, Integer>> index; // Inverted index mapping terms to document id and frequency
+    private Map<Integer, Movie> movies; // Mapping of movie document IDs to Movie objects
+    private int totalDocuments; // Total number of movies/documents
+    private double avgDocumentLength; // Average length of documents (number of words)
+    private static final double K = 1.5; // BM25 tuning parameter, controls term frequency saturation
+    private static final double B = 0.75; // BM25 tuning parameter, controls length normalization
+
+    /**
+     * Constructor for BM25InvertedIndex.
+     * Initializes the inverted index and movie storage.
+     */
+    BM25InvertedIndex() {
+        index = new HashMap<>();
+        movies = new HashMap<>();
+        totalDocuments = 0;
+        avgDocumentLength = 0.0;
+    }
+
+    /**
+     * Add a movie to the index.
+     * @param docId Unique identifier for the movie.
+     * @param name Name of the movie.
+     * @param imdbRating IMDb rating of the movie.
+     * @param releaseYear Release year of the movie.
+     * @param content Content or description of the movie.
+     */
+    public void addMovie(int docId, String name, double imdbRating, int releaseYear, String content) {
+        Movie movie = new Movie(docId, name, imdbRating, releaseYear, content);
+        movies.put(docId, movie);
+        totalDocuments++;
+
+        // Get words (terms) from the movie's name and content
+        String[] terms = movie.getWords();
+        int docLength = terms.length;
+
+        // Update the average document length
+        avgDocumentLength = (avgDocumentLength * (totalDocuments - 1) + docLength) / totalDocuments;
+
+        // Update the inverted index
+        for (String term : terms) {
+            // Create a new entry if the term is not yet in the index
+            index.putIfAbsent(term, new HashMap<>());
+
+            // Get the list of documents containing the term
+            Map<Integer, Integer> docList = index.get(term);
+            if (docList == null) {
+                docList = new HashMap<>();
+                index.put(term, docList); // Ensure docList is added to the index
+            }
+            // Increment the term frequency in this document
+            docList.put(docId, docList.getOrDefault(docId, 0) + 1);
+        }
+    }
+
+    public int getMoviesLength() {
+        return movies.size();
+    }
+
+    /**
+     * Search for documents containing a term using BM25 scoring.
+     * @param term The search term.
+     * @return A list of search results sorted by relevance score.
+     */
+    public List<SearchResult> search(String term) {
+        term = term.toLowerCase(); // Normalize search term
+        if (!index.containsKey(term)) {
+            return new ArrayList<>(); // Return empty list if term not found
+        }
+
+        Map<Integer, Integer> termDocs = index.get(term); // Documents containing the term
+        List<SearchResult> results = new ArrayList<>();
+
+        // Compute IDF for the search term
+        double idf = computeIDF(termDocs.size());
+
+        // Calculate relevance scores for all documents containing the term
+        for (Map.Entry<Integer, Integer> entry : termDocs.entrySet()) {
+            int docId = entry.getKey();
+            int termFrequency = entry.getValue();
+            Movie movie = movies.get(docId);
+            if (movie == null) {
+                continue; // Skip this document if movie doesn't exist
+            }
+            double docLength = movie.getWords().length;
+
+            // Compute BM25 relevance score
+            double score = computeBM25Score(termFrequency, docLength, idf);
+            results.add(new SearchResult(docId, score));
+        }
+
+        // Sort the results by relevance score in descending order
+        results.sort((r1, r2) -> Double.compare(r2.relevanceScore, r1.relevanceScore));
+        return results;
+    }
+
+    /**
+     * Compute the BM25 score for a given term and document.
+     * @param termFrequency The frequency of the term in the document.
+     * @param docLength The length of the document.
+     * @param idf The inverse document frequency of the term.
+     * @return The BM25 relevance score for the term in the document.
+     */
+    private double computeBM25Score(int termFrequency, double docLength, double idf) {
+        double numerator = termFrequency * (K + 1);
+        double denominator = termFrequency + K * (1 - B + B * (docLength / avgDocumentLength));
+        return idf * (numerator / denominator);
+    }
+
+    /**
+     * Compute the inverse document frequency (IDF) of a term.
+     * The IDF measures the importance of a term across the entire document set.
+     * @param docFrequency The number of documents that contain the term.
+     * @return The inverse document frequency (IDF) value.
+     */
+    private double computeIDF(int docFrequency) {
+        // Total number of documents in the index
+        return Math.log((totalDocuments - docFrequency + 0.5) / (docFrequency + 0.5));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java b/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java
new file mode 100644
index 000000000000..8595e0a00683
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java
@@ -0,0 +1,93 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test Cases for Inverted Index with BM25
+ * @author Prayas Kumar (https://github.com/prayas7102)
+ */
+
+class BM25InvertedIndexTest {
+
+    private static BM25InvertedIndex index;
+
+    @BeforeAll
+    static void setUp() {
+        index = new BM25InvertedIndex();
+        index.addMovie(1, "The Shawshank Redemption", 9.3, 1994, "Hope is a good thing. Maybe the best of things. And no good thing ever dies.");
+        index.addMovie(2, "The Godfather", 9.2, 1972, "I'm gonna make him an offer he can't refuse.");
+        index.addMovie(3, "The Dark Knight", 9.0, 2008, "You either die a hero or live long enough to see yourself become the villain.");
+        index.addMovie(4, "Pulp Fiction", 8.9, 1994, "You know what they call a Quarter Pounder with Cheese in Paris? They call it a Royale with Cheese.");
+        index.addMovie(5, "Good Will Hunting", 8.3, 1997, "Will Hunting is a genius and he has a good heart. The best of his abilities is yet to be explored.");
+        index.addMovie(6, "It's a Wonderful Life", 8.6, 1946, "Each man's life touches so many other lives. If he wasn't around, it would leave an awfully good hole.");
+        index.addMovie(7, "The Pursuit of Happyness", 8.0, 2006, "It was the pursuit of a better life, and a good opportunity to change things for the better.");
+        index.addMovie(8, "A Few Good Men", 7.7, 1992, "You can't handle the truth! This movie has a lot of good moments and intense drama.");
+    }
+
+    @Test
+    void testAddMovie() {
+        // Check that the index contains the correct number of movies
+        int moviesLength = index.getMoviesLength();
+        assertEquals(8, moviesLength);
+    }
+
+    @Test
+    void testSearchForTermFound() {
+        int expected = 1;
+        List<SearchResult> result = index.search("hope");
+        int actual = result.getFirst().getDocId();
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void testSearchRanking() {
+        // Perform search for the term "good"
+        List<SearchResult> results = index.search("good");
+        assertFalse(results.isEmpty());
+
+        // Validate the ranking based on the provided relevance scores
+        assertEquals(6, results.get(0).getDocId()); // It's a Wonderful Life should be ranked 1st
+        assertEquals(7, results.get(1).getDocId()); // The Pursuit of Happyness should be ranked 2nd
+        assertEquals(5, results.get(2).getDocId()); // Good Will Hunting should be ranked 3rd
+        assertEquals(8, results.get(3).getDocId()); // A Few Good Men should be ranked 4th
+        assertEquals(1, results.get(4).getDocId()); // The Shawshank Redemption should be ranked 5th
+
+        // Ensure the relevance scores are in descending order
+        for (int i = 0; i < results.size() - 1; i++) {
+            assertTrue(results.get(i).getRelevanceScore() > results.get(i + 1).getRelevanceScore());
+        }
+    }
+
+    @Test
+    void testSearchForTermNotFound() {
+        List<SearchResult> results = index.search("nonexistent");
+        assertTrue(results.isEmpty());
+    }
+
+    @Test
+    void testSearchForCommonTerm() {
+        List<SearchResult> results = index.search("the");
+        assertFalse(results.isEmpty());
+        assertTrue(results.size() > 1);
+    }
+
+    @Test
+    void testBM25ScoreCalculation() {
+        List<SearchResult> results = index.search("cheese");
+        assertEquals(1, results.size());
+        assertEquals(4, results.getFirst().docId); // Pulp Fiction should have the highest score
+    }
+
+    @Test
+    void testCaseInsensitivity() {
+        List<SearchResult> resultsLowerCase = index.search("hope");
+        List<SearchResult> resultsUpperCase = index.search("HOPE");
+        assertEquals(resultsLowerCase, resultsUpperCase);
+    }
+}

From 4a5bf39f8e196efd9772d3708217dd5554d14a1d Mon Sep 17 00:00:00 2001
From: Taranjeet Singh Kalsi <taranjeetkalsi15@gmail.com>
Date: Tue, 8 Oct 2024 00:18:02 +0530
Subject: [PATCH 0453/1338] Add another method to check valid parentheses in
 ValidParentheses.java (#5616)

---
 .../strings/ValidParentheses.java              | 18 ++++++++++++++++++
 .../strings/ValidParenthesesTest.java          |  3 +++
 2 files changed, 21 insertions(+)

diff --git a/src/main/java/com/thealgorithms/strings/ValidParentheses.java b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
index f4f3761b0495..629fee495d84 100644
--- a/src/main/java/com/thealgorithms/strings/ValidParentheses.java
+++ b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
@@ -38,4 +38,22 @@ public static boolean isValid(String s) {
         }
         return head == 0;
     }
+    public static boolean isValidParentheses(String s) {
+        int i = -1;
+        char[] stack = new char[s.length()];
+        String openBrackets = "({[";
+        String closeBrackets = ")}]";
+        for (char ch : s.toCharArray()) {
+            if (openBrackets.indexOf(ch) != -1) {
+                stack[++i] = ch;
+            } else {
+                if (i >= 0 && openBrackets.indexOf(stack[i]) == closeBrackets.indexOf(ch)) {
+                    i--;
+                } else {
+                    return false;
+                }
+            }
+        }
+        return i == -1;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
index 22deb4b14d3c..2b6884c91c8f 100644
--- a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
+++ b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
@@ -10,15 +10,18 @@ public class ValidParenthesesTest {
     @Test
     void testOne() {
         assertTrue(ValidParentheses.isValid("()"));
+        assertTrue(ValidParentheses.isValidParentheses("()"));
     }
 
     @Test
     void testTwo() {
         assertTrue(ValidParentheses.isValid("()[]{}"));
+        assertTrue(ValidParentheses.isValidParentheses("()[]{}"));
     }
 
     @Test
     void testThree() {
         assertFalse(ValidParentheses.isValid("(]"));
+        assertFalse(ValidParentheses.isValidParentheses("(]"));
     }
 }

From 6868bf8ba01041a50fdb37b953ff462d68526879 Mon Sep 17 00:00:00 2001
From: Nandini Pandey <120239212+Nandini-Pandey@users.noreply.github.com>
Date: Tue, 8 Oct 2024 00:28:17 +0530
Subject: [PATCH 0454/1338] Add palindrome singly linkedlist optimised approach
 (#5617)

---
 .../misc/PalindromeSinglyLinkedList.java      | 43 +++++++++++
 .../misc/PalindromeSinglyLinkedListTest.java  | 72 +++++++++++++++++++
 2 files changed, 115 insertions(+)

diff --git a/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java b/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
index 07286b39f2e4..8af8a9b030e1 100644
--- a/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
+++ b/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
@@ -30,4 +30,47 @@ public static boolean isPalindrome(final SinglyLinkedList linkedList) {
 
         return true;
     }
+
+    // Optimised approach with O(n) time complexity and O(1) space complexity
+
+    public static boolean isPalindromeOptimised(Node head) {
+        if (head == null || head.next == null) {
+            return true;
+        }
+        Node slow = head;
+        Node fast = head;
+        while (fast != null && fast.next != null) {
+            slow = slow.next;
+            fast = fast.next.next;
+        }
+        Node midNode = slow;
+
+        Node prevNode = null;
+        Node currNode = midNode;
+        Node nextNode;
+        while (currNode != null) {
+            nextNode = currNode.next;
+            currNode.next = prevNode;
+            prevNode = currNode;
+            currNode = nextNode;
+        }
+        Node left = head;
+        Node right = prevNode;
+        while (left != null && right != null) {
+            if (left.val != right.val) {
+                return false;
+            }
+            right = right.next;
+            left = left.next;
+        }
+        return true;
+    }
+    static class Node {
+        int val;
+        Node next;
+        Node(int val) {
+            this.val = val;
+            this.next = null;
+        }
+    }
 }
diff --git a/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java b/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java
index ae0d6ae0674d..0f0577d39094 100644
--- a/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java
@@ -7,6 +7,8 @@
 import org.junit.jupiter.api.Test;
 
 public class PalindromeSinglyLinkedListTest {
+
+    // Stack-based tests
     @Test
     public void testWithEmptyList() {
         assertTrue(PalindromeSinglyLinkedList.isPalindrome(new SinglyLinkedList()));
@@ -67,4 +69,74 @@ public void testWithListWithEvenLengthNegative() {
         exampleList.insert(20);
         assertFalse(PalindromeSinglyLinkedList.isPalindrome(exampleList));
     }
+
+    // Optimized approach tests
+    @Test
+    public void testOptimisedWithEmptyList() {
+        assertTrue(PalindromeSinglyLinkedList.isPalindromeOptimised(null));
+    }
+
+    @Test
+    public void testOptimisedWithSingleElement() {
+        PalindromeSinglyLinkedList.Node node = new PalindromeSinglyLinkedList.Node(100);
+        assertTrue(PalindromeSinglyLinkedList.isPalindromeOptimised(node));
+    }
+
+    @Test
+    public void testOptimisedWithOddLengthPositive() {
+        PalindromeSinglyLinkedList.Node node1 = new PalindromeSinglyLinkedList.Node(1);
+        PalindromeSinglyLinkedList.Node node2 = new PalindromeSinglyLinkedList.Node(2);
+        PalindromeSinglyLinkedList.Node node3 = new PalindromeSinglyLinkedList.Node(1);
+        node1.next = node2;
+        node2.next = node3;
+        assertTrue(PalindromeSinglyLinkedList.isPalindromeOptimised(node1));
+    }
+
+    @Test
+    public void testOptimisedWithOddLengthPositive2() {
+        PalindromeSinglyLinkedList.Node node1 = new PalindromeSinglyLinkedList.Node(3);
+        PalindromeSinglyLinkedList.Node node2 = new PalindromeSinglyLinkedList.Node(2);
+        PalindromeSinglyLinkedList.Node node3 = new PalindromeSinglyLinkedList.Node(1);
+        PalindromeSinglyLinkedList.Node node4 = new PalindromeSinglyLinkedList.Node(2);
+        PalindromeSinglyLinkedList.Node node5 = new PalindromeSinglyLinkedList.Node(3);
+        node1.next = node2;
+        node2.next = node3;
+        node3.next = node4;
+        node4.next = node5;
+        assertTrue(PalindromeSinglyLinkedList.isPalindromeOptimised(node1));
+    }
+
+    @Test
+    public void testOptimisedWithEvenLengthPositive() {
+        PalindromeSinglyLinkedList.Node node1 = new PalindromeSinglyLinkedList.Node(10);
+        PalindromeSinglyLinkedList.Node node2 = new PalindromeSinglyLinkedList.Node(20);
+        PalindromeSinglyLinkedList.Node node3 = new PalindromeSinglyLinkedList.Node(20);
+        PalindromeSinglyLinkedList.Node node4 = new PalindromeSinglyLinkedList.Node(10);
+        node1.next = node2;
+        node2.next = node3;
+        node3.next = node4;
+        assertTrue(PalindromeSinglyLinkedList.isPalindromeOptimised(node1));
+    }
+
+    @Test
+    public void testOptimisedWithOddLengthNegative() {
+        PalindromeSinglyLinkedList.Node node1 = new PalindromeSinglyLinkedList.Node(1);
+        PalindromeSinglyLinkedList.Node node2 = new PalindromeSinglyLinkedList.Node(2);
+        PalindromeSinglyLinkedList.Node node3 = new PalindromeSinglyLinkedList.Node(2);
+        node1.next = node2;
+        node2.next = node3;
+        assertFalse(PalindromeSinglyLinkedList.isPalindromeOptimised(node1));
+    }
+
+    @Test
+    public void testOptimisedWithEvenLengthNegative() {
+        PalindromeSinglyLinkedList.Node node1 = new PalindromeSinglyLinkedList.Node(10);
+        PalindromeSinglyLinkedList.Node node2 = new PalindromeSinglyLinkedList.Node(20);
+        PalindromeSinglyLinkedList.Node node3 = new PalindromeSinglyLinkedList.Node(20);
+        PalindromeSinglyLinkedList.Node node4 = new PalindromeSinglyLinkedList.Node(20);
+        node1.next = node2;
+        node2.next = node3;
+        node3.next = node4;
+        assertFalse(PalindromeSinglyLinkedList.isPalindromeOptimised(node1));
+    }
 }

From 5dcf6c0f29d6c850709fd27672efc27f337bf8b5 Mon Sep 17 00:00:00 2001
From: Sailok Chinta <sailokchinta2012@gmail.com>
Date: Tue, 8 Oct 2024 02:41:55 +0530
Subject: [PATCH 0455/1338] Enhance Trie data structure with added methods and
 tests (#5538)

---
 DIRECTORY.md                                  |   2 +-
 .../trees/{TrieImp.java => Trie.java}         | 141 +++++++++++++-----
 .../trees/{TrieImpTest.java => TrieTest.java} |  37 +++--
 3 files changed, 129 insertions(+), 51 deletions(-)
 rename src/main/java/com/thealgorithms/datastructures/trees/{TrieImp.java => Trie.java} (50%)
 rename src/test/java/com/thealgorithms/datastructures/trees/{TrieImpTest.java => TrieTest.java} (69%)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 87922528abda..ad337f35fc8f 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -207,7 +207,7 @@
               * [SplayTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SplayTree.java)
               * [Treap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/Treap.java)
               * [TreeRandomNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java)
-              * [TrieImp](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java)
+              * [Trie](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/Trie.java)
               * [VerticalOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java)
               * [ZigzagTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java)
           * devutils
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java b/src/main/java/com/thealgorithms/datastructures/trees/Trie.java
similarity index 50%
rename from src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java
rename to src/main/java/com/thealgorithms/datastructures/trees/Trie.java
index a43a454146cb..02f28d4d83ad 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/TrieImp.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/Trie.java
@@ -1,5 +1,28 @@
 package com.thealgorithms.datastructures.trees;
 
+import java.util.HashMap;
+
+/**
+ * Represents a Trie Node that stores a character and pointers to its children.
+ * Each node has a hashmap which can point to all possible characters.
+ * Each node also has a boolean value to indicate if it is the end of a word.
+ */
+class TrieNode {
+    char value;
+    HashMap<Character, TrieNode> child;
+    boolean end;
+
+    /**
+     * Constructor to initialize a TrieNode with an empty hashmap
+     * and set end to false.
+     */
+    TrieNode(char value) {
+        this.value = value;
+        this.child = new HashMap<>();
+        this.end = false;
+    }
+}
+
 /**
  * Trie Data structure implementation without any libraries.
  * <p>
@@ -14,27 +37,11 @@
  * possible character.
  *
  * @author <a href="https://github.com/dheeraj92">Dheeraj Kumar Barnwal</a>
+ * @author <a href="https://github.com/sailok">Sailok Chinta</a>
  */
-public class TrieImp {
 
-    /**
-     * Represents a Trie Node that stores a character and pointers to its children.
-     * Each node has an array of 26 children (one for each letter from 'a' to 'z').
-     */
-    public class TrieNode {
-
-        TrieNode[] child;
-        boolean end;
-
-        /**
-         * Constructor to initialize a TrieNode with an empty child array
-         * and set end to false.
-         */
-        public TrieNode() {
-            child = new TrieNode[26];
-            end = false;
-        }
-    }
+public class Trie {
+    private static final char ROOT_NODE_VALUE = '*';
 
     private final TrieNode root;
 
@@ -42,8 +49,8 @@ public TrieNode() {
      * Constructor to initialize the Trie.
      * The root node is created but doesn't represent any character.
      */
-    public TrieImp() {
-        root = new TrieNode();
+    public Trie() {
+        root = new TrieNode(ROOT_NODE_VALUE);
     }
 
     /**
@@ -57,13 +64,15 @@ public TrieImp() {
     public void insert(String word) {
         TrieNode currentNode = root;
         for (int i = 0; i < word.length(); i++) {
-            TrieNode node = currentNode.child[word.charAt(i) - 'a'];
+            TrieNode node = currentNode.child.getOrDefault(word.charAt(i), null);
+
             if (node == null) {
-                node = new TrieNode();
-                currentNode.child[word.charAt(i) - 'a'] = node;
+                node = new TrieNode(word.charAt(i));
+                currentNode.child.put(word.charAt(i), node);
             }
             currentNode = node;
         }
+
         currentNode.end = true;
     }
 
@@ -80,13 +89,14 @@ public void insert(String word) {
     public boolean search(String word) {
         TrieNode currentNode = root;
         for (int i = 0; i < word.length(); i++) {
-            char ch = word.charAt(i);
-            TrieNode node = currentNode.child[ch - 'a'];
+            TrieNode node = currentNode.child.getOrDefault(word.charAt(i), null);
+
             if (node == null) {
                 return false;
             }
             currentNode = node;
         }
+
         return currentNode.end;
     }
 
@@ -104,40 +114,89 @@ public boolean search(String word) {
     public boolean delete(String word) {
         TrieNode currentNode = root;
         for (int i = 0; i < word.length(); i++) {
-            char ch = word.charAt(i);
-            TrieNode node = currentNode.child[ch - 'a'];
+            TrieNode node = currentNode.child.getOrDefault(word.charAt(i), null);
             if (node == null) {
                 return false;
             }
+
             currentNode = node;
         }
+
         if (currentNode.end) {
             currentNode.end = false;
             return true;
         }
+
         return false;
     }
 
     /**
-     * Helper method to print a string to the console.
+     * Counts the number of words in the trie
+     *<p>
+     * The method traverses the Trie and counts the number of words.
      *
-     * @param print The string to be printed.
+     * @return count of words
      */
-    public static void sop(String print) {
-        System.out.println(print);
+    public int countWords() {
+        return countWords(root);
+    }
+
+    private int countWords(TrieNode node) {
+        if (node == null) {
+            return 0;
+        }
+
+        int count = 0;
+        if (node.end) {
+            count++;
+        }
+
+        for (TrieNode child : node.child.values()) {
+            count += countWords(child);
+        }
+
+        return count;
     }
 
     /**
-     * Validates if a given word contains only lowercase alphabetic characters
-     * (a-z).
-     * <p>
-     * The method uses a regular expression to check if the word matches the pattern
-     * of only lowercase letters.
+     * Check if the prefix exists in the trie
      *
-     * @param word The word to be validated.
-     * @return true if the word is valid (only a-z), false otherwise.
+     * @param prefix the prefix to be checked in the Trie
+     * @return true / false depending on the prefix if exists in the Trie
      */
-    public static boolean isValid(String word) {
-        return word.matches("^[a-z]+$");
+    public boolean startsWithPrefix(String prefix) {
+        TrieNode currentNode = root;
+
+        for (int i = 0; i < prefix.length(); i++) {
+            TrieNode node = currentNode.child.getOrDefault(prefix.charAt(i), null);
+            if (node == null) {
+                return false;
+            }
+
+            currentNode = node;
+        }
+
+        return true;
+    }
+
+    /**
+     * Count the number of words starting with the given prefix in the trie
+     *
+     * @param prefix the prefix to be checked in the Trie
+     * @return count of words
+     */
+    public int countWordsWithPrefix(String prefix) {
+        TrieNode currentNode = root;
+
+        for (int i = 0; i < prefix.length(); i++) {
+            TrieNode node = currentNode.child.getOrDefault(prefix.charAt(i), null);
+            if (node == null) {
+                return 0;
+            }
+
+            currentNode = node;
+        }
+
+        return countWords(currentNode);
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/TrieImpTest.java b/src/test/java/com/thealgorithms/datastructures/trees/TrieTest.java
similarity index 69%
rename from src/test/java/com/thealgorithms/datastructures/trees/TrieImpTest.java
rename to src/test/java/com/thealgorithms/datastructures/trees/TrieTest.java
index 600fdef0a718..9348118bb343 100644
--- a/src/test/java/com/thealgorithms/datastructures/trees/TrieImpTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/trees/TrieTest.java
@@ -1,17 +1,21 @@
 package com.thealgorithms.datastructures.trees;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.util.List;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class TrieImpTest {
-    private TrieImp trie;
+public class TrieTest {
+    private static final List<String> WORDS = List.of("Apple", "App", "app", "APPLE");
+
+    private Trie trie;
 
     @BeforeEach
     public void setUp() {
-        trie = new TrieImp();
+        trie = new Trie();
     }
 
     @Test
@@ -66,11 +70,26 @@ public void testInsertAndSearchPrefix() {
     }
 
     @Test
-    public void testIsValidWord() {
-        assertTrue(TrieImp.isValid("validword"), "Word should be valid (only lowercase letters).");
-        assertFalse(TrieImp.isValid("InvalidWord"), "Word should be invalid (contains uppercase letters).");
-        assertFalse(TrieImp.isValid("123abc"), "Word should be invalid (contains numbers).");
-        assertFalse(TrieImp.isValid("hello!"), "Word should be invalid (contains special characters).");
-        assertFalse(TrieImp.isValid(""), "Empty string should be invalid.");
+    public void testCountWords() {
+        Trie trie = createTrie();
+        assertEquals(WORDS.size(), trie.countWords(), "Count words should return the correct number of words.");
+    }
+
+    @Test
+    public void testStartsWithPrefix() {
+        Trie trie = createTrie();
+        assertTrue(trie.startsWithPrefix("App"), "Starts with prefix should return true.");
+    }
+
+    @Test
+    public void testCountWordsWithPrefix() {
+        Trie trie = createTrie();
+        assertEquals(2, trie.countWordsWithPrefix("App"), "Count words with prefix should return 2.");
+    }
+
+    private Trie createTrie() {
+        Trie trie = new Trie();
+        WORDS.forEach(trie::insert);
+        return trie;
     }
 }

From bd9e324e8c522032cabc0b7c267df7d53ad77b91 Mon Sep 17 00:00:00 2001
From: Sailok Chinta <sailokchinta2012@gmail.com>
Date: Tue, 8 Oct 2024 02:47:45 +0530
Subject: [PATCH 0456/1338] Add QuadraticEquationSolver and test cases (#5619)

---
 DIRECTORY.md                                  |  1 +
 .../maths/QuadraticEquationSolver.java        | 60 +++++++++++++++++++
 .../maths/QuadraticEquationSolverTest.java    | 50 ++++++++++++++++
 3 files changed, 111 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/QuadraticEquationSolver.java
 create mode 100644 src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index ad337f35fc8f..1cd30a336f24 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -377,6 +377,7 @@
             * [PrimeFactorization](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PrimeFactorization.java)
             * [PronicNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PronicNumber.java)
             * [PythagoreanTriple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java)
+            * [QuadraticEquationSolver](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/QuadraticEquationSolver.java)
             * [ReverseNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ReverseNumber.java)
             * [RomanNumeralUtil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/RomanNumeralUtil.java)
             * [SecondMinMax](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SecondMinMax.java)
diff --git a/src/main/java/com/thealgorithms/maths/QuadraticEquationSolver.java b/src/main/java/com/thealgorithms/maths/QuadraticEquationSolver.java
new file mode 100644
index 000000000000..cd654c5dc023
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/QuadraticEquationSolver.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.maths;
+
+/**
+ * This class represents a complex number which has real and imaginary part
+ */
+class ComplexNumber {
+    Double real;
+    Double imaginary;
+
+    ComplexNumber(double real, double imaginary) {
+        this.real = real;
+        this.imaginary = imaginary;
+    }
+
+    ComplexNumber(double real) {
+        this.real = real;
+        this.imaginary = null;
+    }
+}
+
+/**
+ * Quadratic Equation Formula is used to find
+ * the roots of a quadratic equation of the form ax^2 + bx + c = 0
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Quadratic_equation">Quadratic Equation</a>
+ */
+public class QuadraticEquationSolver {
+    /**
+     * Function takes in the coefficients of the quadratic equation
+     *
+     * @param a is the coefficient of x^2
+     * @param b is the coefficient of x
+     * @param c is the constant
+     * @return roots of the equation which are ComplexNumber type
+     */
+    public ComplexNumber[] solveEquation(double a, double b, double c) {
+        double discriminant = b * b - 4 * a * c;
+
+        // if discriminant is positive, roots will be different
+        if (discriminant > 0) {
+            return new ComplexNumber[] {new ComplexNumber((-b + Math.sqrt(discriminant)) / (2 * a)), new ComplexNumber((-b - Math.sqrt(discriminant)) / (2 * a))};
+        }
+
+        // if discriminant is zero, roots will be same
+        if (discriminant == 0) {
+            return new ComplexNumber[] {new ComplexNumber((-b) / (2 * a))};
+        }
+
+        // if discriminant is negative, roots will have imaginary parts
+        if (discriminant < 0) {
+            double realPart = -b / (2 * a);
+            double imaginaryPart = Math.sqrt(-discriminant) / (2 * a);
+
+            return new ComplexNumber[] {new ComplexNumber(realPart, imaginaryPart), new ComplexNumber(realPart, -imaginaryPart)};
+        }
+
+        // return no roots
+        return new ComplexNumber[] {};
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java b/src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java
new file mode 100644
index 000000000000..a2046511ddf5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java
@@ -0,0 +1,50 @@
+package com.thealgorithms.maths;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class QuadraticEquationSolverTest {
+    private final QuadraticEquationSolver quadraticEquationSolver = new QuadraticEquationSolver();
+
+    @Test
+    public void testSolveEquationRealRoots() {
+        // 4.2x^2 + 8x + 1.9 = 0
+        double a = 4.2;
+        double b = 8;
+        double c = 1.9;
+
+        ComplexNumber[] roots = quadraticEquationSolver.solveEquation(a, b, c);
+        Assertions.assertEquals(roots.length, 2);
+        Assertions.assertEquals(roots[0].real, -0.27810465435684306);
+        Assertions.assertNull(roots[0].imaginary);
+        Assertions.assertEquals(roots[1].real, -1.6266572504050616);
+        Assertions.assertNull(roots[1].imaginary);
+    }
+
+    @Test
+    public void testSolveEquationEqualRoots() {
+        // x^2 + 2x + 1 = 0
+        double a = 1;
+        double b = 2;
+        double c = 1;
+
+        ComplexNumber[] roots = quadraticEquationSolver.solveEquation(a, b, c);
+        Assertions.assertEquals(roots.length, 1);
+        Assertions.assertEquals(roots[0].real, -1);
+    }
+
+    @Test
+    public void testSolveEquationComplexRoots() {
+        // 2.3x^2 + 4x + 5.6 = 0
+        double a = 2.3;
+        double b = 4;
+        double c = 5.6;
+
+        ComplexNumber[] roots = quadraticEquationSolver.solveEquation(a, b, c);
+        Assertions.assertEquals(roots.length, 2);
+        Assertions.assertEquals(roots[0].real, -0.8695652173913044);
+        Assertions.assertEquals(roots[0].imaginary, 1.2956229935435948);
+        Assertions.assertEquals(roots[1].real, -0.8695652173913044);
+        Assertions.assertEquals(roots[1].imaginary, -1.2956229935435948);
+    }
+}

From 9fb819235643b8a6afa392b65e72a46036c4c210 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 8 Oct 2024 02:54:57 +0530
Subject: [PATCH 0457/1338] Add QueueByTwoStacks algorithm (#5623)

---
 DIRECTORY.md                                  |  7 +-
 .../queues/QueueByTwoStacks.java              | 87 +++++++++++++++++++
 .../queues/QueueByTwoStacksTest.java          | 69 +++++++++++++++
 3 files changed, 162 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 1cd30a336f24..228735aa8ea9 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -170,6 +170,7 @@
               * [LinkedQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java)
               * [PriorityQueues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java)
               * [Queue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/Queue.java)
+              * [QueueByTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java)
             * stacks
               * [NodeStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java)
               * [ReverseStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java)
@@ -477,6 +478,7 @@
           * searches
             * [BinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BinarySearch.java)
             * [BinarySearch2dArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java)
+            * [BM25InvertedIndex](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java)
             * [BreadthFirstSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java)
             * [DepthFirstSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/DepthFirstSearch.java)
             * [ExponentalSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/ExponentalSearch.java)
@@ -731,6 +733,7 @@
               * [GenericArrayListQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java)
               * [LinkedQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java)
               * [PriorityQueuesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java)
+              * [QueueByTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java)
               * [QueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java)
             * stacks
               * [LinkedListStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java)
@@ -756,7 +759,7 @@
               * [SplayTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java)
               * [TreapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java)
               * [TreeTestUtils](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java)
-              * [TrieImpTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TrieImpTest.java)
+              * [TrieTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TrieTest.java)
               * [VerticalOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversalTest.java)
               * [ZigzagTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/ZigzagTraversalTest.java)
           * divideandconquer
@@ -887,6 +890,7 @@
             * [PrimeFactorizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java)
             * [PronicNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PronicNumberTest.java)
             * [PythagoreanTripleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java)
+            * [QuadraticEquationSolverTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java)
             * [ReverseNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ReverseNumberTest.java)
             * [SecondMinMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java)
             * [SieveOfEratosthenesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java)
@@ -952,6 +956,7 @@
             * [SRTFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java)
           * searches
             * [BinarySearch2dArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java)
+            * [BM25InvertedIndexTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java)
             * [BreadthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java)
             * [DepthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java)
             * [HowManyTimesRotatedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java b/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java
new file mode 100644
index 000000000000..11e5e9b83892
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java
@@ -0,0 +1,87 @@
+package com.thealgorithms.datastructures.queues;
+
+import java.util.NoSuchElementException;
+import java.util.Stack;
+
+/**
+ * A queue implementation using two stacks. This class provides methods to
+ * enqueue (add) elements to the end of the queue and dequeue (remove)
+ * elements from the front, while utilizing two internal stacks to manage
+ * the order of elements.
+ *
+ * @param <T> The type of elements held in this queue.
+ */
+public class QueueByTwoStacks<T> {
+
+    private final Stack<T> enqueueStk;
+    private final Stack<T> dequeueStk;
+
+    /**
+     * Constructor that initializes two empty stacks for the queue.
+     * The `enqueueStk` is used to push elements when enqueuing, and
+     * the `dequeueStk` is used to pop elements when dequeuing.
+     */
+    public QueueByTwoStacks() {
+        enqueueStk = new Stack<>();
+        dequeueStk = new Stack<>();
+    }
+
+    /**
+     * Adds an element to the end of the queue. This method pushes the element
+     * onto the `enqueueStk`.
+     *
+     * @param item The element to be added to the queue.
+     */
+    public void put(T item) {
+        enqueueStk.push(item);
+    }
+
+    /**
+     * Removes and returns the element at the front of the queue.
+     * If `dequeueStk` is empty, it transfers all elements from
+     * `enqueueStk` to `dequeueStk` to maintain the correct FIFO
+     * (First-In-First-Out) order before popping.
+     *
+     * @return The element at the front of the queue.
+     * @throws NoSuchElementException If the queue is empty.
+     */
+    public T get() {
+        if (dequeueStk.isEmpty()) {
+            while (!enqueueStk.isEmpty()) {
+                dequeueStk.push(enqueueStk.pop());
+            }
+        }
+        if (dequeueStk.isEmpty()) {
+            throw new NoSuchElementException("Queue is empty");
+        }
+        return dequeueStk.pop();
+    }
+
+    /**
+     * Returns the total number of elements currently in the queue.
+     * This is the sum of the sizes of both stacks.
+     *
+     * @return The number of elements in the queue.
+     */
+    public int size() {
+        return enqueueStk.size() + dequeueStk.size();
+    }
+
+    /**
+     * Returns a string representation of the queue, showing the elements
+     * in the correct order (from front to back).
+     * The `dequeueStk` is first cloned, and then all elements from the
+     * `enqueueStk` are added to the cloned stack in reverse order to
+     * represent the queue accurately.
+     *
+     * @return A string representation of the queue.
+     */
+    @Override
+    public String toString() {
+        Stack<T> tempStack = (Stack<T>) dequeueStk.clone();
+        while (!enqueueStk.isEmpty()) {
+            tempStack.push(enqueueStk.pop());
+        }
+        return "Queue(" + tempStack + ")";
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java b/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java
new file mode 100644
index 000000000000..87f136a84631
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.datastructures.queues;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.NoSuchElementException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class QueueByTwoStacksTest {
+
+    private QueueByTwoStacks<Integer> queue;
+
+    @BeforeEach
+    public void setUp() {
+        queue = new QueueByTwoStacks<>();
+    }
+
+    @Test
+    public void testEmptyQueue() {
+        assertEquals(0, queue.size());
+    }
+
+    @Test
+    public void testEnqueue() {
+        queue.put(10);
+        queue.put(20);
+        assertEquals(2, queue.size());
+    }
+
+    @Test
+    public void testDequeue() {
+        queue.put(10);
+        queue.put(20);
+        queue.put(30);
+        assertEquals(10, queue.get()); // First item out
+        assertEquals(20, queue.get()); // Second item out
+        assertEquals(30, queue.get()); // Third item out
+    }
+
+    @Test
+    public void testInterleavedOperations() {
+        queue.put(10);
+        queue.put(20);
+        assertEquals(10, queue.get()); // Dequeue first item
+        queue.put(30);
+        assertEquals(20, queue.get()); // Dequeue second item
+        assertEquals(30, queue.get()); // Dequeue third item
+    }
+
+    @Test
+    public void testQueueSize() {
+        assertEquals(0, queue.size());
+        queue.put(1);
+        assertEquals(1, queue.size());
+        queue.put(2);
+        queue.put(3);
+        assertEquals(3, queue.size());
+        queue.get();
+        assertEquals(2, queue.size());
+    }
+
+    @Test
+    public void testEmptyQueueException() {
+        assertThrows(NoSuchElementException.class, () -> {
+            queue.get(); // Attempting to dequeue from empty queue
+        });
+    }
+}

From 0b86774991740bc7f0a1071a342279b861683560 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 8 Oct 2024 09:14:21 +0200
Subject: [PATCH 0458/1338] Chore(deps): bump
 org.apache.maven.plugins:maven-surefire-plugin from 3.5.0 to 3.5.1 (#5632)

Chore(deps): bump org.apache.maven.plugins:maven-surefire-plugin

Bumps [org.apache.maven.plugins:maven-surefire-plugin](https://github.com/apache/maven-surefire) from 3.5.0 to 3.5.1.
- [Release notes](https://github.com/apache/maven-surefire/releases)
- [Commits](https://github.com/apache/maven-surefire/compare/surefire-3.5.0...surefire-3.5.1)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-surefire-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index ab12e8ec4082..673be6cd4e36 100644
--- a/pom.xml
+++ b/pom.xml
@@ -63,7 +63,7 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.5.0</version>
+                <version>3.5.1</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>

From 0d68b655d21d7f8d6a996f64c2e6f5d33eba95b5 Mon Sep 17 00:00:00 2001
From: Tuhinm2002 <75078694+Tuhinm2002@users.noreply.github.com>
Date: Tue, 8 Oct 2024 13:25:34 +0530
Subject: [PATCH 0459/1338] feat : new dp algo added
 `UniqueSubsequenceCount.java` (#5586)

* feat : new algo uniquesubseqcount

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

---------

Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 .../UniqueSubsequencesCount.java              | 98 +++++++++++++++++++
 .../UniqueSubsequencesCountTest.java          | 15 +++
 2 files changed, 113 insertions(+)
 create mode 100755 src/main/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCount.java
 create mode 100755 src/test/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCountTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCount.java b/src/main/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCount.java
new file mode 100755
index 000000000000..8c7ea6179e3f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCount.java
@@ -0,0 +1,98 @@
+package com.thealgorithms.dynamicprogramming;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Utility class to find the number of unique subsequences that can be
+ * produced from a given string.
+ *
+ * <p> This class contains static methods to compute the unique subsequence count
+ * using dynamic programming and recursion. It ensures that duplicate characters
+ * are not counted multiple times in the subsequences.</p>
+ *
+ * <p> Author: https://github.com/Tuhinm2002 </p>
+ */
+public final class UniqueSubsequencesCount {
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     * This class should only be used in a static context.
+     *
+     * @throws UnsupportedOperationException if attempted to instantiate.
+     */
+    private UniqueSubsequencesCount() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    /**
+     * Finds the number of unique subsequences that can be generated from
+     * the given string.
+     *
+     * <p> This method initializes a dynamic programming (DP) array and invokes
+     * the recursive helper function to compute the subsequence count.</p>
+     *
+     * @param str the input string from which subsequences are generated
+     * @return the total count of unique subsequences
+     */
+    public static int countSubseq(String str) {
+
+        // DP array initialized to store intermediate results
+        int[] dp = new int[str.length() + 1];
+        Arrays.fill(dp, -1);
+
+        // Calls the recursive function to compute the result
+        return countSubsequences(str, 0, dp);
+    }
+
+    /**
+     * Recursive helper function to count the number of unique subsequences
+     * starting from the given index.
+     *
+     * <p> Uses a HashSet to avoid counting duplicate characters within
+     * a single subsequence.</p>
+     *
+     * @param st the input string
+     * @param idx the current index from which to calculate subsequences
+     * @param dp dynamic programming array used to memoize results
+     * @return the total number of unique subsequences starting from the
+     *         current index
+     */
+    public static int countSubsequences(String st, int idx, int[] dp) {
+
+        // Base case: when index exceeds the string length
+        if (idx >= st.length()) {
+            return 0;
+        }
+
+        // If result is already calculated, return the memoized value
+        if (dp[idx] != -1) {
+            return dp[idx];
+        }
+
+        // Set to store characters to avoid duplicates
+        Set<Character> set = new HashSet<>();
+
+        int res = 0;
+
+        // Iterate over the string starting from current index
+        for (int j = idx; j < st.length(); j++) {
+
+            // If character is already in the set, skip it
+            if (set.contains(st.charAt(j))) {
+                continue;
+            }
+
+            // Add character to set and recursively calculate subsequences
+            set.add(st.charAt(j));
+
+            // 1 for the current subsequence + recursive call for the rest of the string
+            res = 1 + countSubsequences(st, j + 1, dp) + res;
+        }
+
+        // Memoize the result
+        dp[idx] = res;
+        return dp[idx];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCountTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCountTest.java
new file mode 100755
index 000000000000..049804f58b5a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCountTest.java
@@ -0,0 +1,15 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class UniqueSubsequencesCountTest {
+
+    @ParameterizedTest
+    @CsvSource({"abc, 7", "abcdashgdhas, 3592", "a, 1", "'a b', 7", "a1b2, 15", "AaBb, 15", "abab, 11"})
+    void subseqCountParameterizedTest(String input, int expected) {
+        assertEquals(expected, UniqueSubsequencesCount.countSubseq(input));
+    }
+}

From 136e0e23a4eac52484034ff878d5ec1db6659bbf Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 8 Oct 2024 21:47:56 +0530
Subject: [PATCH 0460/1338] Add SortStack algorithm (#5624)

---
 DIRECTORY.md                                  |  4 +
 .../com/thealgorithms/stacks/SortStack.java   | 60 +++++++++++++++
 .../thealgorithms/stacks/SortStackTest.java   | 77 +++++++++++++++++++
 3 files changed, 141 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/SortStack.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/SortStackTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 228735aa8ea9..9fb1112924f3 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -267,6 +267,7 @@
             * [SumOfSubset](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java)
             * [Tribonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java)
             * [UniquePaths](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java)
+            * [UniqueSubsequencesCount](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCount.java)
             * [WildcardMatching](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java)
             * [WineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java)
           * geometry
@@ -566,6 +567,7 @@
             * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
             * [PostfixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java)
             * [PrefixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PrefixToInfix.java)
+            * [SortStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/SortStack.java)
             * [StackPostfixNotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
           * strings
             * [AhoCorasick](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/AhoCorasick.java)
@@ -794,6 +796,7 @@
             * [SumOfSubsetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java)
             * [TribonacciTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java)
             * [UniquePathsTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java)
+            * [UniqueSubsequencesCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCountTest.java)
             * [WildcardMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java)
           * geometry
             * [GrahamScanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
@@ -1027,6 +1030,7 @@
             * [NextSmallerElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
             * [PostfixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java)
             * [PrefixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java)
+            * [SortStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/SortStackTest.java)
             * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
           * strings
             * [AhoCorasickTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
diff --git a/src/main/java/com/thealgorithms/stacks/SortStack.java b/src/main/java/com/thealgorithms/stacks/SortStack.java
new file mode 100644
index 000000000000..d07d1a5f1dc3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/SortStack.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.stacks;
+
+import java.util.Stack;
+
+/**
+ * A utility class that provides a method to sort a stack using recursion.
+ * The elements are sorted in ascending order, with the largest element at the top.
+ * This algorithm is implemented using only recursion and the original stack,
+ * without utilizing any additional data structures apart from the stack itself.
+ */
+public final class SortStack {
+    private SortStack() {
+    }
+
+    /**
+     * Sorts the given stack in ascending order using recursion.
+     * The sorting is performed such that the largest element ends up on top of the stack.
+     * This method modifies the original stack and does not return a new stack.
+     *
+     * The algorithm works as follows:
+     * 1. Remove the top element.
+     * 2. Recursively sort the remaining stack.
+     * 3. Insert the removed element back into the sorted stack at the correct position.
+     *
+     * @param stack The stack to be sorted, containing Integer elements.
+     * @throws IllegalArgumentException if the stack contains `null` elements.
+     */
+    public static void sortStack(Stack<Integer> stack) {
+        if (stack.isEmpty()) {
+            return;
+        }
+
+        int top = stack.pop();
+        sortStack(stack);
+        insertInSortedOrder(stack, top);
+    }
+
+    /**
+     * Helper method to insert an element into the correct position in a sorted stack.
+     * This method is called recursively to place the given element into the stack
+     * such that the stack remains sorted in ascending order.
+     *
+     * The element is inserted in such a way that all elements below it are smaller
+     * (if the stack is non-empty), and elements above it are larger, maintaining
+     * the ascending order.
+     *
+     * @param stack The stack in which the element needs to be inserted.
+     * @param element The element to be inserted into the stack in sorted order.
+     */
+    private static void insertInSortedOrder(Stack<Integer> stack, int element) {
+        if (stack.isEmpty() || element > stack.peek()) {
+            stack.push(element);
+            return;
+        }
+
+        int top = stack.pop();
+        insertInSortedOrder(stack, element);
+        stack.push(top);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/SortStackTest.java b/src/test/java/com/thealgorithms/stacks/SortStackTest.java
new file mode 100644
index 000000000000..b9f2f1b6f106
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/SortStackTest.java
@@ -0,0 +1,77 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Stack;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class SortStackTest {
+
+    private Stack<Integer> stack;
+
+    @BeforeEach
+    public void setUp() {
+        stack = new Stack<>();
+    }
+
+    @Test
+    public void testSortEmptyStack() {
+        SortStack.sortStack(stack);
+        assertTrue(stack.isEmpty()); // An empty stack should remain empty
+    }
+
+    @Test
+    public void testSortSingleElementStack() {
+        stack.push(10);
+        SortStack.sortStack(stack);
+        assertEquals(1, stack.size());
+        assertEquals(10, (int) stack.peek()); // Single element should remain unchanged
+    }
+
+    @Test
+    public void testSortAlreadySortedStack() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+        stack.push(4);
+        SortStack.sortStack(stack);
+
+        assertEquals(4, stack.size());
+        assertEquals(4, (int) stack.pop());
+        assertEquals(3, (int) stack.pop());
+        assertEquals(2, (int) stack.pop());
+        assertEquals(1, (int) stack.pop());
+    }
+
+    @Test
+    public void testSortUnsortedStack() {
+        stack.push(3);
+        stack.push(1);
+        stack.push(4);
+        stack.push(2);
+        SortStack.sortStack(stack);
+
+        assertEquals(4, stack.size());
+        assertEquals(4, (int) stack.pop());
+        assertEquals(3, (int) stack.pop());
+        assertEquals(2, (int) stack.pop());
+        assertEquals(1, (int) stack.pop());
+    }
+
+    @Test
+    public void testSortWithDuplicateElements() {
+        stack.push(3);
+        stack.push(1);
+        stack.push(3);
+        stack.push(2);
+        SortStack.sortStack(stack);
+
+        assertEquals(4, stack.size());
+        assertEquals(3, (int) stack.pop());
+        assertEquals(3, (int) stack.pop());
+        assertEquals(2, (int) stack.pop());
+        assertEquals(1, (int) stack.pop());
+    }
+}

From d3bd2874c83a0cb14c564f01d3e45c9b823f4960 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 8 Oct 2024 23:07:10 +0530
Subject: [PATCH 0461/1338] Add StackUsingTwoQueues algorithm (#5625)

---
 DIRECTORY.md                                  |  2 +
 .../stacks/StackUsingTwoQueues.java           | 91 +++++++++++++++++++
 .../stacks/StackUsingTwoQueuesTest.java       | 70 ++++++++++++++
 3 files changed, 163 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/StackUsingTwoQueues.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/StackUsingTwoQueuesTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 9fb1112924f3..7a1bb728fac2 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -569,6 +569,7 @@
             * [PrefixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PrefixToInfix.java)
             * [SortStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/SortStack.java)
             * [StackPostfixNotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
+            * [StackUsingTwoQueues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackUsingTwoQueues.java)
           * strings
             * [AhoCorasick](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/AhoCorasick.java)
             * [Alphabetical](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Alphabetical.java)
@@ -1032,6 +1033,7 @@
             * [PrefixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java)
             * [SortStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/SortStackTest.java)
             * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
+            * [StackUsingTwoQueuesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackUsingTwoQueuesTest.java)
           * strings
             * [AhoCorasickTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
             * [AlphabeticalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java)
diff --git a/src/main/java/com/thealgorithms/stacks/StackUsingTwoQueues.java b/src/main/java/com/thealgorithms/stacks/StackUsingTwoQueues.java
new file mode 100644
index 000000000000..5b1ca5d1d5a5
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/StackUsingTwoQueues.java
@@ -0,0 +1,91 @@
+package com.thealgorithms.stacks;
+
+import java.util.LinkedList;
+import java.util.NoSuchElementException;
+import java.util.Queue;
+
+/**
+ * A class that implements a stack using two queues.
+ * This approach ensures that the stack's LIFO (Last In, First Out) behavior
+ * is maintained by utilizing two queues for storage.
+ * The mainQueue is used to store the elements of the stack, while the tempQueue
+ * is used to temporarily store elements during the push operation.
+ */
+public class StackUsingTwoQueues {
+
+    private Queue<Integer> mainQueue;
+    private Queue<Integer> tempQueue;
+
+    /**
+     * Constructs an empty stack using two queues.
+     */
+    public StackUsingTwoQueues() {
+        mainQueue = new LinkedList<>();
+        tempQueue = new LinkedList<>();
+    }
+
+    /**
+     * Pushes an element onto the top of the stack.
+     * The newly pushed element becomes the top of the stack.
+     *
+     * @param item The element to be pushed onto the stack.
+     */
+    public void push(int item) {
+        tempQueue.add(item);
+
+        // Move all elements from the mainQueue to tempQueue to maintain LIFO order
+        while (!mainQueue.isEmpty()) {
+            tempQueue.add(mainQueue.remove());
+        }
+
+        // Swap the names of the two queues
+        Queue<Integer> swap = mainQueue;
+        mainQueue = tempQueue;
+        tempQueue = swap; // tempQueue is now empty
+    }
+
+    /**
+     * Removes and returns the element at the top of the stack.
+     * Throws an exception if the stack is empty.
+     *
+     * @return The element at the top of the stack.
+     * @throws NoSuchElementException if the stack is empty.
+     */
+    public int pop() {
+        if (mainQueue.isEmpty()) {
+            throw new NoSuchElementException("Stack is empty");
+        }
+        return mainQueue.remove();
+    }
+
+    /**
+     * Returns the element at the top of the stack without removing it.
+     * Returns null if the stack is empty.
+     *
+     * @return The element at the top of the stack, or null if the stack is empty.
+     */
+    public Integer peek() {
+        if (mainQueue.isEmpty()) {
+            return null;
+        }
+        return mainQueue.peek();
+    }
+
+    /**
+     * Returns true if the stack is empty.
+     *
+     * @return true if the stack is empty; false otherwise.
+     */
+    public boolean isEmpty() {
+        return mainQueue.isEmpty();
+    }
+
+    /**
+     * Returns the number of elements in the stack.
+     *
+     * @return The size of the stack.
+     */
+    public int size() {
+        return mainQueue.size();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/StackUsingTwoQueuesTest.java b/src/test/java/com/thealgorithms/stacks/StackUsingTwoQueuesTest.java
new file mode 100644
index 000000000000..a7e24421e682
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/StackUsingTwoQueuesTest.java
@@ -0,0 +1,70 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class StackUsingTwoQueuesTest {
+
+    private StackUsingTwoQueues stack;
+
+    @BeforeEach
+    public void setUp() {
+        stack = new StackUsingTwoQueues();
+    }
+
+    @Test
+    public void testPushAndPeek() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+        assertEquals(3, stack.peek());
+    }
+
+    @Test
+    public void testPop() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+        assertEquals(3, stack.pop());
+        assertEquals(2, stack.pop());
+        assertEquals(1, stack.pop());
+    }
+
+    @Test
+    public void testPeek() {
+        stack.push(10);
+        stack.push(20);
+        assertEquals(20, stack.peek());
+        stack.pop();
+        assertEquals(10, stack.peek());
+    }
+
+    @Test
+    public void testIsEmpty() {
+        assertTrue(stack.isEmpty());
+        stack.push(1);
+        assertFalse(stack.isEmpty());
+        stack.pop();
+        assertTrue(stack.isEmpty());
+    }
+
+    @Test
+    public void testSize() {
+        assertEquals(0, stack.size());
+        stack.push(1);
+        stack.push(2);
+        assertEquals(2, stack.size());
+        stack.pop();
+        assertEquals(1, stack.size());
+    }
+
+    @Test
+    public void testPeekEmptyStack() {
+        assertNull(stack.peek());
+    }
+}

From 435532fb7bd20e7077403ef2fe64b31ce9fc7ae1 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 8 Oct 2024 23:15:17 +0530
Subject: [PATCH 0462/1338] Add WordPatternMatcher algorithm (#5627)

---
 DIRECTORY.md                                  |  2 +
 .../backtracking/WordPatternMatcher.java      | 86 +++++++++++++++++++
 .../backtracking/WordPatternMatcherTest.java  | 40 +++++++++
 3 files changed, 128 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/backtracking/WordPatternMatcher.java
 create mode 100644 src/test/java/com/thealgorithms/backtracking/WordPatternMatcherTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7a1bb728fac2..1b69d17e347d 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -19,6 +19,7 @@
             * [Permutation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/Permutation.java)
             * [PowerSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/PowerSum.java)
             * [SubsequenceFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/SubsequenceFinder.java)
+            * [WordPatternMatcher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordPatternMatcher.java)
             * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
           * bitmanipulation
             * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
@@ -624,6 +625,7 @@
             * [PermutationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PermutationTest.java)
             * [PowerSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PowerSumTest.java)
             * [SubsequenceFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/SubsequenceFinderTest.java)
+            * [WordPatternMatcherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordPatternMatcherTest.java)
             * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
           * bitmanipulation
             * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
diff --git a/src/main/java/com/thealgorithms/backtracking/WordPatternMatcher.java b/src/main/java/com/thealgorithms/backtracking/WordPatternMatcher.java
new file mode 100644
index 000000000000..1854cab20a7f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/backtracking/WordPatternMatcher.java
@@ -0,0 +1,86 @@
+package com.thealgorithms.backtracking;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Class to determine if a pattern matches a string using backtracking.
+ *
+ * Example:
+ * Pattern: "abab"
+ * Input String: "JavaPythonJavaPython"
+ * Output: true
+ *
+ * Pattern: "aaaa"
+ * Input String: "JavaJavaJavaJava"
+ * Output: true
+ *
+ * Pattern: "aabb"
+ * Input String: "JavaPythonPythonJava"
+ * Output: false
+ */
+public final class WordPatternMatcher {
+    private WordPatternMatcher() {
+    }
+
+    /**
+     * Determines if the given pattern matches the input string using backtracking.
+     *
+     * @param pattern The pattern to match.
+     * @param inputString The string to match against the pattern.
+     * @return True if the pattern matches the string, False otherwise.
+     */
+    public static boolean matchWordPattern(String pattern, String inputString) {
+        Map<Character, String> patternMap = new HashMap<>();
+        Map<String, Character> strMap = new HashMap<>();
+        return backtrack(pattern, inputString, 0, 0, patternMap, strMap);
+    }
+
+    /**
+     * Backtracking helper function to check if the pattern matches the string.
+     *
+     * @param pattern The pattern string.
+     * @param inputString The string to match against the pattern.
+     * @param patternIndex Current index in the pattern.
+     * @param strIndex Current index in the input string.
+     * @param patternMap Map to store pattern characters to string mappings.
+     * @param strMap Map to store string to pattern character mappings.
+     * @return True if the pattern matches, False otherwise.
+     */
+    private static boolean backtrack(String pattern, String inputString, int patternIndex, int strIndex, Map<Character, String> patternMap, Map<String, Character> strMap) {
+        if (patternIndex == pattern.length() && strIndex == inputString.length()) {
+            return true;
+        }
+        if (patternIndex == pattern.length() || strIndex == inputString.length()) {
+            return false;
+        }
+
+        char currentChar = pattern.charAt(patternIndex);
+        if (patternMap.containsKey(currentChar)) {
+            String mappedStr = patternMap.get(currentChar);
+            if (inputString.startsWith(mappedStr, strIndex)) {
+                return backtrack(pattern, inputString, patternIndex + 1, strIndex + mappedStr.length(), patternMap, strMap);
+            } else {
+                return false;
+            }
+        }
+
+        for (int end = strIndex + 1; end <= inputString.length(); end++) {
+            String substring = inputString.substring(strIndex, end);
+            if (strMap.containsKey(substring)) {
+                continue;
+            }
+
+            patternMap.put(currentChar, substring);
+            strMap.put(substring, currentChar);
+            if (backtrack(pattern, inputString, patternIndex + 1, end, patternMap, strMap)) {
+                return true;
+            }
+
+            patternMap.remove(currentChar);
+            strMap.remove(substring);
+        }
+
+        return false;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/backtracking/WordPatternMatcherTest.java b/src/test/java/com/thealgorithms/backtracking/WordPatternMatcherTest.java
new file mode 100644
index 000000000000..4d56be566035
--- /dev/null
+++ b/src/test/java/com/thealgorithms/backtracking/WordPatternMatcherTest.java
@@ -0,0 +1,40 @@
+package com.thealgorithms.backtracking;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class WordPatternMatcherTest {
+
+    @Test
+    public void testPatternMatchingSuccess() {
+        assertTrue(WordPatternMatcher.matchWordPattern("aba", "GraphTreesGraph"));
+        assertTrue(WordPatternMatcher.matchWordPattern("xyx", "PythonRubyPython"));
+    }
+
+    @Test
+    public void testPatternMatchingFailure() {
+        assertFalse(WordPatternMatcher.matchWordPattern("GG", "PythonJavaPython"));
+    }
+
+    @Test
+    public void testEmptyPatternAndString() {
+        assertTrue(WordPatternMatcher.matchWordPattern("", ""));
+    }
+
+    @Test
+    public void testEmptyPattern() {
+        assertFalse(WordPatternMatcher.matchWordPattern("", "nonempty"));
+    }
+
+    @Test
+    public void testEmptyString() {
+        assertFalse(WordPatternMatcher.matchWordPattern("abc", ""));
+    }
+
+    @Test
+    public void testLongerPatternThanString() {
+        assertFalse(WordPatternMatcher.matchWordPattern("abcd", "abc"));
+    }
+}

From ecd75c0c2eb962b12eb1b03098ed246b521d1ac7 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 8 Oct 2024 23:30:02 +0530
Subject: [PATCH 0463/1338] Add CrosswordSolver algorithm (#5626)

---
 DIRECTORY.md                                  |   2 +
 .../backtracking/CrosswordSolver.java         | 124 ++++++++++++++++++
 .../backtracking/CrosswordSolverTest.java     |  66 ++++++++++
 3 files changed, 192 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java
 create mode 100644 src/test/java/com/thealgorithms/backtracking/CrosswordSolverTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 1b69d17e347d..7c6f284c9e43 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -10,6 +10,7 @@
             * [AllPathsFromSourceToTarget](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java)
             * [ArrayCombination](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java)
             * [Combination](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/Combination.java)
+            * [CrosswordSolver](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java)
             * [FloodFill](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/FloodFill.java)
             * [KnightsTour](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/KnightsTour.java)
             * [MazeRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java)
@@ -616,6 +617,7 @@
             * [AllPathsFromSourceToTargetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/AllPathsFromSourceToTargetTest.java)
             * [ArrayCombinationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java)
             * [CombinationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/CombinationTest.java)
+            * [CrosswordSolverTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/CrosswordSolverTest.java)
             * [FloodFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/FloodFillTest.java)
             * [KnightsTourTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/KnightsTourTest.java)
             * [MazeRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java)
diff --git a/src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java b/src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java
new file mode 100644
index 000000000000..cbd9f70f74f4
--- /dev/null
+++ b/src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java
@@ -0,0 +1,124 @@
+package com.thealgorithms.backtracking;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A class to solve a crossword puzzle using backtracking.
+ * Example:
+ * Input:
+ *  puzzle = {
+ *      {' ', ' ', ' '},
+ *      {' ', ' ', ' '},
+ *      {' ', ' ', ' '}
+ *  }
+ *  words = List.of("cat", "dog")
+ *
+ * Output:
+ *  {
+ *      {'c', 'a', 't'},
+ *      {' ', ' ', ' '},
+ *      {'d', 'o', 'g'}
+ *  }
+ */
+public final class CrosswordSolver {
+    private CrosswordSolver() {
+    }
+
+    /**
+     * Checks if a word can be placed at the specified position in the crossword.
+     *
+     * @param puzzle   The crossword puzzle represented as a 2D char array.
+     * @param word     The word to be placed.
+     * @param row      The row index where the word might be placed.
+     * @param col      The column index where the word might be placed.
+     * @param vertical If true, the word is placed vertically; otherwise, horizontally.
+     * @return true if the word can be placed, false otherwise.
+     */
+    public static boolean isValid(char[][] puzzle, String word, int row, int col, boolean vertical) {
+        for (int i = 0; i < word.length(); i++) {
+            if (vertical) {
+                if (row + i >= puzzle.length || puzzle[row + i][col] != ' ') {
+                    return false;
+                }
+            } else {
+                if (col + i >= puzzle[0].length || puzzle[row][col + i] != ' ') {
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Places a word at the specified position in the crossword.
+     *
+     * @param puzzle   The crossword puzzle represented as a 2D char array.
+     * @param word     The word to be placed.
+     * @param row      The row index where the word will be placed.
+     * @param col      The column index where the word will be placed.
+     * @param vertical If true, the word is placed vertically; otherwise, horizontally.
+     */
+    public static void placeWord(char[][] puzzle, String word, int row, int col, boolean vertical) {
+        for (int i = 0; i < word.length(); i++) {
+            if (vertical) {
+                puzzle[row + i][col] = word.charAt(i);
+            } else {
+                puzzle[row][col + i] = word.charAt(i);
+            }
+        }
+    }
+
+    /**
+     * Removes a word from the specified position in the crossword.
+     *
+     * @param puzzle   The crossword puzzle represented as a 2D char array.
+     * @param word     The word to be removed.
+     * @param row      The row index where the word is placed.
+     * @param col      The column index where the word is placed.
+     * @param vertical If true, the word was placed vertically; otherwise, horizontally.
+     */
+    public static void removeWord(char[][] puzzle, String word, int row, int col, boolean vertical) {
+        for (int i = 0; i < word.length(); i++) {
+            if (vertical) {
+                puzzle[row + i][col] = ' ';
+            } else {
+                puzzle[row][col + i] = ' ';
+            }
+        }
+    }
+
+    /**
+     * Solves the crossword puzzle using backtracking.
+     *
+     * @param puzzle The crossword puzzle represented as a 2D char array.
+     * @param words  The list of words to be placed.
+     * @return true if the crossword is solved, false otherwise.
+     */
+    public static boolean solveCrossword(char[][] puzzle, List<String> words) {
+        // Create a mutable copy of the words list
+        List<String> remainingWords = new ArrayList<>(words);
+
+        for (int row = 0; row < puzzle.length; row++) {
+            for (int col = 0; col < puzzle[0].length; col++) {
+                if (puzzle[row][col] == ' ') {
+                    for (String word : new ArrayList<>(remainingWords)) {
+                        for (boolean vertical : new boolean[] {true, false}) {
+                            if (isValid(puzzle, word, row, col, vertical)) {
+                                placeWord(puzzle, word, row, col, vertical);
+                                remainingWords.remove(word);
+                                if (solveCrossword(puzzle, remainingWords)) {
+                                    return true;
+                                }
+                                remainingWords.add(word);
+                                removeWord(puzzle, word, row, col, vertical);
+                            }
+                        }
+                    }
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/backtracking/CrosswordSolverTest.java b/src/test/java/com/thealgorithms/backtracking/CrosswordSolverTest.java
new file mode 100644
index 000000000000..542fd53fe5ed
--- /dev/null
+++ b/src/test/java/com/thealgorithms/backtracking/CrosswordSolverTest.java
@@ -0,0 +1,66 @@
+package com.thealgorithms.backtracking;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class CrosswordSolverTest {
+
+    @Test
+    public void testValidPlacement() {
+        char[][] puzzle = {{' ', ' ', ' '}, {' ', ' ', ' '}, {' ', ' ', ' '}};
+        assertTrue(CrosswordSolver.isValid(puzzle, "cat", 0, 0, true));
+        assertTrue(CrosswordSolver.isValid(puzzle, "dog", 0, 0, false));
+        assertFalse(CrosswordSolver.isValid(puzzle, "cat", 1, 2, false));
+    }
+
+    @Test
+    public void testPlaceAndRemoveWord() {
+        char[][] puzzle = {{' ', ' ', ' '}, {' ', ' ', ' '}, {' ', ' ', ' '}};
+        CrosswordSolver.placeWord(puzzle, "cat", 0, 0, true);
+        assertEquals('c', puzzle[0][0]);
+        assertEquals('a', puzzle[1][0]);
+        assertEquals('t', puzzle[2][0]);
+
+        CrosswordSolver.removeWord(puzzle, "cat", 0, 0, true);
+        assertEquals(' ', puzzle[0][0]);
+        assertEquals(' ', puzzle[1][0]);
+        assertEquals(' ', puzzle[2][0]);
+    }
+
+    @Test
+    public void testSolveCrossword() {
+        char[][] puzzle = {{' ', ' ', ' '}, {' ', ' ', ' '}, {' ', ' ', ' '}};
+        List<String> words = Arrays.asList("cat", "dog", "car");
+        assertTrue(CrosswordSolver.solveCrossword(puzzle, words));
+
+        /* Solved crossword:
+         * c d c
+         * a o a
+         * t g r
+         */
+
+        assertEquals('c', puzzle[0][0]);
+        assertEquals('a', puzzle[1][0]);
+        assertEquals('t', puzzle[2][0]);
+
+        assertEquals('d', puzzle[0][1]);
+        assertEquals('o', puzzle[1][1]);
+        assertEquals('g', puzzle[2][1]);
+
+        assertEquals('c', puzzle[0][2]);
+        assertEquals('a', puzzle[1][2]);
+        assertEquals('r', puzzle[2][2]);
+    }
+
+    @Test
+    public void testNoSolution() {
+        char[][] puzzle = {{' ', ' ', ' '}, {' ', ' ', ' '}, {' ', ' ', ' '}};
+        List<String> words = Arrays.asList("cat", "dog", "elephant"); // 'elephant' is too long for the grid
+        assertFalse(CrosswordSolver.solveCrossword(puzzle, words));
+    }
+}

From d437d581f4d280f632e663fc528e0a9c2605cbf4 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 8 Oct 2024 23:37:46 +0530
Subject: [PATCH 0464/1338] Remove `print` & `main` methods (#5584)

---
 DIRECTORY.md                                  |  1 +
 .../datastructures/graphs/FloydWarshall.java  | 79 +++++++++++--------
 .../graphs/FloydWarshallTest.java             | 33 ++++++++
 3 files changed, 81 insertions(+), 32 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/FloydWarshallTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7c6f284c9e43..6042dd1b5e0d 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -709,6 +709,7 @@
               * [BoruvkaAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
               * [DijkstraAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java)
               * [EdmondsBlossomAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java)
+              * [FloydWarshallTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FloydWarshallTest.java)
               * [FordFulkersonTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java)
               * [HamiltonianCycleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java)
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java b/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
index d47ffe3aa27d..66dc6782a8be 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
@@ -1,21 +1,46 @@
 package com.thealgorithms.datastructures.graphs;
 
-import java.util.Scanner;
-
+/**
+ * The {@code FloydWarshall} class provides an implementation of the Floyd-Warshall algorithm
+ * to compute the shortest paths between all pairs of vertices in a weighted graph.
+ * It handles both positive and negative edge weights but does not support negative cycles.
+ * The algorithm is based on dynamic programming and runs in O(V^3) time complexity,
+ * where V is the number of vertices in the graph.
+ *
+ * <p>
+ * The distance matrix is updated iteratively to find the shortest distance between any two vertices
+ * by considering each vertex as an intermediate step.
+ * </p>
+ *
+ * Reference: <a href="https://en.wikipedia.org/wiki/Floyd%E2%80%93Warshall_algorithm">Floyd-Warshall Algorithm</a>
+ */
 public class FloydWarshall {
 
     private int[][] distanceMatrix;
-    private int numberofvertices; // number of vertices in the graph
+    private int numberofvertices;
     public static final int INFINITY = 999;
 
+    /**
+     * Constructs a Floyd-Warshall instance for a graph with the given number of vertices.
+     * Initializes the distance matrix for the graph.
+     *
+     * @param numberofvertices The number of vertices in the graph.
+     */
     public FloydWarshall(int numberofvertices) {
-        distanceMatrix = new int[numberofvertices + 1][numberofvertices + 1]; // stores the value of distance from all the possible path form the source
-        // vertex to destination vertex
+        distanceMatrix = new int[numberofvertices + 1][numberofvertices + 1];
         // The matrix is initialized with 0's by default
         this.numberofvertices = numberofvertices;
     }
 
-    public void floydwarshall(int[][] adjacencyMatrix) { // calculates all the distances from source to destination vertex
+    /**
+     * Executes the Floyd-Warshall algorithm to compute the shortest path between all pairs of vertices.
+     * It uses an adjacency matrix to calculate the distance matrix by considering each vertex as an intermediate point.
+     *
+     * @param adjacencyMatrix The weighted adjacency matrix representing the graph.
+     *                        A value of 0 means no direct edge between the vertices, except for diagonal elements which are 0 (distance to self).
+     */
+    public void floydwarshall(int[][] adjacencyMatrix) {
+        // Initialize the distance matrix with the adjacency matrix.
         for (int source = 1; source <= numberofvertices; source++) {
             for (int destination = 1; destination <= numberofvertices; destination++) {
                 distanceMatrix[source][destination] = adjacencyMatrix[source][destination];
@@ -24,19 +49,29 @@ public void floydwarshall(int[][] adjacencyMatrix) { // calculates all the dista
         for (int intermediate = 1; intermediate <= numberofvertices; intermediate++) {
             for (int source = 1; source <= numberofvertices; source++) {
                 for (int destination = 1; destination <= numberofvertices; destination++) {
-                    if (distanceMatrix[source][intermediate] + distanceMatrix[intermediate][destination] < distanceMatrix[source][destination]) { // calculated distance it get replaced as
-                                                                                                                                                  // new shortest distance // if the new
-                                                                                                                                                  // distance calculated is less then the
-                                                                                                                                                  // earlier shortest
+                    // Update distance if a shorter path through the intermediate vertex exists.
+                    if (distanceMatrix[source][intermediate] + distanceMatrix[intermediate][destination] < distanceMatrix[source][destination]) {
                         distanceMatrix[source][destination] = distanceMatrix[source][intermediate] + distanceMatrix[intermediate][destination];
                     }
                 }
             }
         }
+
+        printDistanceMatrix();
+    }
+
+    /**
+     * Prints the distance matrix representing the shortest paths between all pairs of vertices.
+     * The rows and columns correspond to the source and destination vertices.
+     */
+    private void printDistanceMatrix() {
+        // Print header for vertices
         for (int source = 1; source <= numberofvertices; source++) {
             System.out.print("\t" + source);
         }
         System.out.println();
+
+        // Print the distance matrix
         for (int source = 1; source <= numberofvertices; source++) {
             System.out.print(source + "\t");
             for (int destination = 1; destination <= numberofvertices; destination++) {
@@ -46,27 +81,7 @@ public void floydwarshall(int[][] adjacencyMatrix) { // calculates all the dista
         }
     }
 
-    public static void main(String... arg) {
-        Scanner scan = new Scanner(System.in);
-        System.out.println("Enter the number of vertices");
-        int numberOfVertices = scan.nextInt();
-        int[][] adjacencyMatrix = new int[numberOfVertices + 1][numberOfVertices + 1];
-        System.out.println("Enter the Weighted Matrix for the graph");
-        for (int source = 1; source <= numberOfVertices; source++) {
-            for (int destination = 1; destination <= numberOfVertices; destination++) {
-                adjacencyMatrix[source][destination] = scan.nextInt();
-                if (source == destination) {
-                    adjacencyMatrix[source][destination] = 0;
-                    continue;
-                }
-                if (adjacencyMatrix[source][destination] == 0) {
-                    adjacencyMatrix[source][destination] = INFINITY;
-                }
-            }
-        }
-        System.out.println("The Transitive Closure of the Graph");
-        FloydWarshall floydwarshall = new FloydWarshall(numberOfVertices);
-        floydwarshall.floydwarshall(adjacencyMatrix);
-        scan.close();
+    public Object[] getDistanceMatrix() {
+        return distanceMatrix;
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/FloydWarshallTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/FloydWarshallTest.java
new file mode 100644
index 000000000000..7d6a2b239f4b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/FloydWarshallTest.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+class FloydWarshallTest {
+
+    @Test
+    void testSmallGraph() {
+        int[][] adjacencyMatrix = {{0, 0, 0, 0}, // Ignored row (0 index)
+            {0, 0, 3, FloydWarshall.INFINITY}, {0, FloydWarshall.INFINITY, 0, 1}, {0, FloydWarshall.INFINITY, FloydWarshall.INFINITY, 0}};
+
+        FloydWarshall fw = new FloydWarshall(3);
+        fw.floydwarshall(adjacencyMatrix);
+
+        int[][] expectedDistanceMatrix = {{0, 0, 0, 0}, {0, 0, 3, 4}, {0, FloydWarshall.INFINITY, 0, 1}, {0, FloydWarshall.INFINITY, FloydWarshall.INFINITY, 0}};
+
+        assertArrayEquals(expectedDistanceMatrix, fw.getDistanceMatrix());
+    }
+
+    @Test
+    void testLargerGraph() {
+        int[][] adjacencyMatrix = {{0, 0, 0, 0, 0}, {0, 0, 1, FloydWarshall.INFINITY, 2}, {0, FloydWarshall.INFINITY, 0, 4, FloydWarshall.INFINITY}, {0, FloydWarshall.INFINITY, FloydWarshall.INFINITY, 0, 3}, {0, FloydWarshall.INFINITY, FloydWarshall.INFINITY, FloydWarshall.INFINITY, 0}};
+
+        FloydWarshall fw = new FloydWarshall(4);
+        fw.floydwarshall(adjacencyMatrix);
+
+        int[][] expectedDistanceMatrix = {{0, 0, 0, 0, 0}, {0, 0, 1, 5, 2}, {0, FloydWarshall.INFINITY, 0, 4, 7}, {0, FloydWarshall.INFINITY, FloydWarshall.INFINITY, 0, 3}, {0, FloydWarshall.INFINITY, FloydWarshall.INFINITY, FloydWarshall.INFINITY, 0}};
+
+        assertArrayEquals(expectedDistanceMatrix, fw.getDistanceMatrix());
+    }
+}

From f3b2a94e74ab00fa32f2fc64a01955e49fddc405 Mon Sep 17 00:00:00 2001
From: Manish Raj <2200032955@kluniversity.in>
Date: Tue, 8 Oct 2024 23:59:29 +0530
Subject: [PATCH 0465/1338] Improve power sum algorithm (#5652)

* Update directory

* Improve PowerSum algorithm implementation and documentation

This commit enhances the PowerSum class in the backtracking package. The changes focus on improving code quality, readability, and documentation. Key improvements include:

1. Enhanced code structure and efficiency:
   - Removed class-level variables for better thread safety
   - Optimized the recursive approach to avoid unnecessary calculations
   - Simplified the overall logic for easier understanding

2. Improved readability:
   - Used more descriptive variable names (e.g., 'targetSum' instead of 'n', 'power' instead of 'x')
   - Enhanced method structure with a private recursive helper method

3. Better documentation:
   - Added comprehensive JavaDoc comments explaining the algorithm's purpose and implementation
   - Clarified the meaning of parameters, especially relating them to the original problem statement (N and X)
   - Improved inline comments for better code understanding

4. Adhered to Java best practices:
   - Improved encapsulation by making the recursive method private
   - Used Math.pow() directly instead of a custom power method

5. Maintained core functionality:
   - The algorithm still solves the same problem as before, but with improved code quality

* updated PowerSum

* Refactor PowerSum algorithm implementation and documentation

* Refactor PowerSum algorithm implementation and documentation

* Refactor code formatting and remove unnecessary line in PowerSum.java

* Refactor code formatting and add newline at end of file in .clang-format

---------

Co-authored-by: manishraj27 <manishraj27@users.noreply.github.com>
Co-authored-by: Bama Charan Chhandogi <b.c.chhandogi@gmail.com>
---
 .../thealgorithms/backtracking/PowerSum.java  | 72 ++++++++++---------
 1 file changed, 39 insertions(+), 33 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/PowerSum.java b/src/main/java/com/thealgorithms/backtracking/PowerSum.java
index 6617ea326a1c..b34ba660ebd7 100644
--- a/src/main/java/com/thealgorithms/backtracking/PowerSum.java
+++ b/src/main/java/com/thealgorithms/backtracking/PowerSum.java
@@ -1,45 +1,51 @@
 package com.thealgorithms.backtracking;
 
-/*
- * Problem Statement :
- * Find the number of ways that a given integer, N , can be expressed as the sum of the Xth powers
- * of unique, natural numbers. For example, if N=100 and X=3, we have to find all combinations of
- * unique cubes adding up to 100. The only solution is 1^3+2^3+3^3+4^3. Therefore output will be 1.
+/**
+ * Problem Statement:
+ * Find the number of ways that a given integer, N, can be expressed as the sum of the Xth powers
+ * of unique, natural numbers.
+ * For example, if N=100 and X=3, we have to find all combinations of unique cubes adding up to 100.
+ * The only solution is 1^3 + 2^3 + 3^3 + 4^3. Therefore, the output will be 1.
+ *
+ * N is represented by the parameter 'targetSum' in the code.
+ * X is represented by the parameter 'power' in the code.
  */
 public class PowerSum {
 
-    private int count = 0;
-    private int sum = 0;
-
-    public int powSum(int n, int x) {
-        sum(n, x, 1);
-        return count;
+    /**
+     * Calculates the number of ways to express the target sum as a sum of Xth powers of unique natural numbers.
+     *
+     * @param targetSum The target sum to achieve (N in the problem statement)
+     * @param power The power to raise natural numbers to (X in the problem statement)
+     * @return The number of ways to express the target sum
+     */
+    public int powSum(int targetSum, int power) {
+        // Special case: when both targetSum and power are zero
+        if (targetSum == 0 && power == 0) {
+            return 1; // by convention, one way to sum to zero: use nothing
+        }
+        return sumRecursive(targetSum, power, 1, 0);
     }
 
-    // here i is the natural number which will be raised by X and added in sum.
-    public void sum(int n, int x, int i) {
-        // if sum is equal to N that is one of our answer and count is increased.
-        if (sum == n) {
-            count++;
-            return;
-        } // we will be adding next natural number raised to X only if on adding it in sum the
-          // result is less than N.
-        else if (sum + power(i, x) <= n) {
-            sum += power(i, x);
-            sum(n, x, i + 1);
-            // backtracking and removing the number added last since no possible combination is
-            // there with it.
-            sum -= power(i, x);
+    /**
+     * Recursively calculates the number of ways to express the remaining sum as a sum of Xth powers.
+     *
+     * @param remainingSum The remaining sum to achieve
+     * @param power The power to raise natural numbers to (X in the problem statement)
+     * @param currentNumber The current natural number being considered
+     * @param currentSum The current sum of powered numbers
+     * @return The number of valid combinations
+     */
+    private int sumRecursive(int remainingSum, int power, int currentNumber, int currentSum) {
+        int newSum = currentSum + (int) Math.pow(currentNumber, power);
+
+        if (newSum == remainingSum) {
+            return 1;
         }
-        if (power(i, x) < n) {
-            // calling the sum function with next natural number after backtracking if when it is
-            // raised to X is still less than X.
-            sum(n, x, i + 1);
+        if (newSum > remainingSum) {
+            return 0;
         }
-    }
 
-    // creating a separate power function so that it can be used again and again when required.
-    private int power(int a, int b) {
-        return (int) Math.pow(a, b);
+        return sumRecursive(remainingSum, power, currentNumber + 1, newSum) + sumRecursive(remainingSum, power, currentNumber + 1, currentSum);
     }
 }

From b54cc21ade112e20f429964dc86f8543a5605d98 Mon Sep 17 00:00:00 2001
From: Lakshyajeet Singh Goyal
 <74810454+DarkMatter-999@users.noreply.github.com>
Date: Wed, 9 Oct 2024 00:12:24 +0530
Subject: [PATCH 0466/1338] Add NumberAppearingOddTimes algorithm (#5633)

---
 .../NumberAppearingOddTimes.java              | 21 +++++++++++++++++
 .../NumberAppearingOddTimesTest.java          | 23 +++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java b/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java
new file mode 100644
index 000000000000..ce4e1d88da6e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * Find the Number Appearing Odd Times in an array
+ * @author Lakshyajeet Singh Goyal (https://github.com/DarkMatter-999)
+ */
+
+public final class NumberAppearingOddTimes {
+    private NumberAppearingOddTimes() {
+    }
+    public static int findOddOccurrence(int[] arr) {
+        int result = 0;
+
+        // XOR all elements in the array
+        for (int num : arr) {
+            result ^= num;
+        }
+
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java b/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java
new file mode 100644
index 000000000000..d10b0f67b806
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class NumberAppearingOddTimesTest {
+
+    @Test
+    void testFindOddOccurrence() {
+        int[] arr1 = {5, 6, 7, 8};
+        assertEquals(12, NumberAppearingOddTimes.findOddOccurrence(arr1));
+
+        int[] arr2 = {2, 3, 5, 4, 5, 2, 4, 3, 5, 2, 4, 4, 2};
+        assertEquals(5, NumberAppearingOddTimes.findOddOccurrence(arr2));
+
+        int[] arr3 = {10, 10, 20, 20, 30};
+        assertEquals(30, NumberAppearingOddTimes.findOddOccurrence(arr3));
+
+        int[] arr4 = {-5, -5, -3, -3, -7, -7, -7};
+        assertEquals(-7, NumberAppearingOddTimes.findOddOccurrence(arr4));
+    }
+}

From 403649d40416916db23ad106a3dc90f051ffb547 Mon Sep 17 00:00:00 2001
From: Albin Sabu <126412402+albinsabu2023@users.noreply.github.com>
Date: Wed, 9 Oct 2024 11:17:47 +0530
Subject: [PATCH 0467/1338] Update CreateAndDetectLoop with tests (#5561)

---
 .../lists/CreateAndDetectLoop.java            | 115 +++++++-----------
 .../lists/CreateAndDetectLoopTest.java        |  71 +++++++++++
 2 files changed, 115 insertions(+), 71 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java b/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
index 441c95702050..49115b2d0f3d 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
@@ -1,63 +1,66 @@
 package com.thealgorithms.datastructures.lists;
 
-import java.util.Scanner;
-
 public final class CreateAndDetectLoop {
+
+    // Node class representing a single node in the linked list
     private CreateAndDetectLoop() {
+        throw new UnsupportedOperationException("Utility class");
     }
+    static final class Node {
+        int data;
+        Node next;
 
-    /**
-     * Prints the linked list.
-     *
-     * @param	head	head node of the linked list
-     */
-    static void printList(Node head) {
-        Node cur = head;
-
-        while (cur != null) {
-            System.out.print(cur.value + " ");
-            cur = cur.next;
+        Node(int data) {
+            this.data = data;
+            next = null;
         }
     }
 
-    /**
-     * Creates a loop in the linked list.
-     *
-     * @see
-     * 	<a href="https://www.geeksforgeeks.org/make-loop-k-th-position-linked-list/">
-     * GeeksForGeeks: Make a loop at K-th position</a>
-     * @param	head	head node of the linked list
-     * @param	k	position of node where loop is to be created
+    // Method to create a loop between two specific positions in the linked list
+    /*
+     *  Test case that shows the Cycle(loop) in a LinkedList
+     *  Let's take this linked list:
+     *  1->2->3->4->5->6
+     *     \______/
+     *   In this linked list we can see there is a cycle.
+     *   we can create loop by calling createLoop function in main after creating LL
+     *   createLoop(head,2,5);
+     *  to detect there is loop or not we can call detectloop function in main
+     *  detectloop(head);
      */
-    static void createLoop(Node head, int k) {
-        if (head == null) {
+
+    static void createLoop(Node head, int position1, int position2) {
+        if (position1 == 0 || position2 == 0) {
             return;
         }
-        Node temp = head;
-        int count = 1;
-        while (count < k) { // Traverse the list till the kth node
-            temp = temp.next;
-            count++;
-        }
 
-        Node connectedPoint = temp;
+        Node node1 = head;
+        Node node2 = head;
 
-        while (temp.next != null) { // Traverse remaining nodes
-            temp = temp.next;
+        int count1 = 1;
+        int count2 = 1;
+        // Traverse to find node at position1
+        while (count1 < position1 && node1 != null) {
+            node1 = node1.next;
+            count1++;
         }
 
-        temp.next = connectedPoint; // Connect last node to k-th element
-    }
+        // Traverse to find node at position2
+        while (count2 < position2 && node2 != null) {
+            node2 = node2.next;
+            count2++;
+        }
 
+        // Create a loop by connecting node2's next to node1
+        if (node1 != null && node2 != null) {
+            node2.next = node1;
+        }
+    }
+    // Method to detect a loop in the linked list
     /**
      * Detects the presence of a loop in the linked list.
      *
-     * @see
-     * 	<a href="https://en.wikipedia.org/wiki/Cycle_detection#Floyd's_tortoise_and_hare">
-     * Floyd's Cycle Detection Algorithm</a>
-     *
-     * @param head the head node of the linked list
-     *
+     * @see <a href="https://en.wikipedia.org/wiki/Cycle_detection#Floyd's_tortoise_and_hare">Floyd's Cycle Detection Algorithm</a>
      * @return true if loop exists else false
      */
     static boolean detectLoop(Node head) {
@@ -67,40 +70,10 @@ static boolean detectLoop(Node head) {
         while (fptr != null && fptr.next != null) {
             sptr = sptr.next;
             fptr = fptr.next.next;
-            if (fptr == sptr) {
+            if (sptr == fptr) {
                 return true;
             }
         }
-
         return false;
     }
-
-    public static void main(String[] args) {
-        SinglyLinkedList singlyLinkedList = new SinglyLinkedList();
-        Scanner sc = new Scanner(System.in);
-
-        System.out.println("Enter the number of elements to be inserted: ");
-        int n = sc.nextInt();
-        System.out.printf("Enter the %d elements: %n", n);
-        while (n-- > 0) {
-            singlyLinkedList.insert(sc.nextInt());
-        }
-
-        System.out.print("Given list: ");
-        printList(singlyLinkedList.getHead());
-        System.out.println();
-
-        System.out.println("Enter the location to generate loop: ");
-        int k = sc.nextInt();
-
-        createLoop(singlyLinkedList.getHead(), k);
-
-        if (detectLoop(singlyLinkedList.getHead())) {
-            System.out.println("Loop found");
-        } else {
-            System.out.println("No loop found");
-        }
-
-        sc.close();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java b/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java
new file mode 100644
index 000000000000..5e9d4c3a2913
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java
@@ -0,0 +1,71 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class CreateAndDetectLoopTest {
+
+    private CreateAndDetectLoop.Node head;
+
+    @BeforeEach
+    void setUp() {
+        // Create a linked list: 1 -> 2 -> 3 -> 4 -> 5 -> 6
+        head = new CreateAndDetectLoop.Node(1);
+        CreateAndDetectLoop.Node second = new CreateAndDetectLoop.Node(2);
+        CreateAndDetectLoop.Node third = new CreateAndDetectLoop.Node(3);
+        CreateAndDetectLoop.Node fourth = new CreateAndDetectLoop.Node(4);
+        CreateAndDetectLoop.Node fifth = new CreateAndDetectLoop.Node(5);
+        CreateAndDetectLoop.Node sixth = new CreateAndDetectLoop.Node(6);
+
+        head.next = second;
+        second.next = third;
+        third.next = fourth;
+        fourth.next = fifth;
+        fifth.next = sixth;
+    }
+
+    @Test
+    void testDetectLoopNoLoop() {
+        // Test when no loop exists
+        assertFalse(CreateAndDetectLoop.detectLoop(head), "There should be no loop.");
+    }
+
+    @Test
+    void testCreateAndDetectLoopLoopExists() {
+        // Create a loop between position 2 (node with value 2) and position 5 (node with value 5)
+        CreateAndDetectLoop.createLoop(head, 2, 5);
+
+        // Now test if the loop is detected
+        assertTrue(CreateAndDetectLoop.detectLoop(head), "A loop should be detected.");
+    }
+
+    @Test
+    void testCreateLoopInvalidPosition() {
+        // Create loop with invalid positions
+        CreateAndDetectLoop.createLoop(head, 0, 0);
+
+        // Ensure no loop was created
+        assertFalse(CreateAndDetectLoop.detectLoop(head), "There should be no loop with invalid positions.");
+    }
+
+    @Test
+    void testCreateLoopSelfLoop() {
+        // Create a self-loop at position 3 (node with value 3)
+        CreateAndDetectLoop.createLoop(head, 3, 3);
+
+        // Test if the self-loop is detected
+        assertTrue(CreateAndDetectLoop.detectLoop(head), "A self-loop should be detected.");
+    }
+
+    @Test
+    void testCreateLoopNoChangeForNonExistentPositions() {
+        // Create a loop with positions that don't exist in the linked list
+        CreateAndDetectLoop.createLoop(head, 10, 20);
+
+        // Ensure no loop was created
+        assertFalse(CreateAndDetectLoop.detectLoop(head), "No loop should be created if positions are out of bounds.");
+    }
+}

From 5c79e5de5d7fc07d089b3e20a75584c5b6cadbe3 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 9 Oct 2024 11:26:08 +0530
Subject: [PATCH 0468/1338] Add MedianOfTwoSortedArrays algorithm (#5554)

---
 DIRECTORY.md                                  |  5 ++
 .../MedianOfTwoSortedArrays.java              | 53 +++++++++++++++++++
 .../MedianOfTwoSortedArraysTest.java          | 41 ++++++++++++++
 3 files changed, 99 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArrays.java
 create mode 100644 src/test/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArraysTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6042dd1b5e0d..af1e4f284445 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -31,6 +31,7 @@
             * [IsPowerTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java)
             * [LowestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/LowestSetBit.java)
             * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
+            * [NumberAppearingOddTimes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
             * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
             * [SingleBitOperations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java)
@@ -228,6 +229,7 @@
           * divideandconquer
             * [BinaryExponentiation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java)
             * [ClosestPair](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java)
+            * [MedianOfTwoSortedArrays](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArrays.java)
             * [SkylineAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java)
             * [StrassenMatrixMultiplication](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplication.java)
           * dynamicprogramming
@@ -638,6 +640,7 @@
             * [IsPowerTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java)
             * [LowestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java)
             * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
+            * [NumberAppearingOddTimesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
             * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
             * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
@@ -729,6 +732,7 @@
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
+              * [CreateAndDetectLoopTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java)
               * [QuickSortLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java)
               * [ReverseKGroupTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java)
               * [RotateSinglyLinkedListsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java)
@@ -773,6 +777,7 @@
           * divideandconquer
             * [BinaryExponentiationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java)
             * [ClosestPairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java)
+            * [MedianOfTwoSortedArraysTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArraysTest.java)
             * [SkylineAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java)
             * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
           * dynamicprogramming
diff --git a/src/main/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArrays.java b/src/main/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArrays.java
new file mode 100644
index 000000000000..d9e51442253c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArrays.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.divideandconquer;
+
+public final class MedianOfTwoSortedArrays {
+
+    private MedianOfTwoSortedArrays() {
+    }
+
+    /**
+     * Finds the median of two sorted arrays in logarithmic time.
+     *
+     * @param nums1 the first sorted array
+     * @param nums2 the second sorted array
+     * @return the median of the combined sorted array
+     * @throws IllegalArgumentException if the input arrays are not sorted
+     */
+    public static double findMedianSortedArrays(int[] nums1, int[] nums2) {
+        if (nums1.length > nums2.length) {
+            return findMedianSortedArrays(nums2, nums1); // Ensure nums1 is the smaller array
+        }
+
+        int m = nums1.length;
+        int n = nums2.length;
+        int low = 0;
+        int high = m;
+        while (low <= high) {
+            int partition1 = (low + high) / 2; // Partition in the first array
+            int partition2 = (m + n + 1) / 2 - partition1; // Partition in the second array
+
+            int maxLeft1 = (partition1 == 0) ? Integer.MIN_VALUE : nums1[partition1 - 1];
+            int minRight1 = (partition1 == m) ? Integer.MAX_VALUE : nums1[partition1];
+            int maxLeft2 = (partition2 == 0) ? Integer.MIN_VALUE : nums2[partition2 - 1];
+            int minRight2 = (partition2 == n) ? Integer.MAX_VALUE : nums2[partition2];
+
+            // Check if partition is valid
+            if (maxLeft1 <= minRight2 && maxLeft2 <= minRight1) {
+                // If combined array length is odd
+                if (((m + n) & 1) == 1) {
+                    return Math.max(maxLeft1, maxLeft2);
+                }
+                // If combined array length is even
+                else {
+                    return (Math.max(maxLeft1, maxLeft2) + Math.min(minRight1, minRight2)) / 2.0;
+                }
+            } else if (maxLeft1 > minRight2) {
+                high = partition1 - 1;
+            } else {
+                low = partition1 + 1;
+            }
+        }
+
+        throw new IllegalArgumentException("Input arrays are not sorted");
+    }
+}
diff --git a/src/test/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArraysTest.java b/src/test/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArraysTest.java
new file mode 100644
index 000000000000..6cfbc2379600
--- /dev/null
+++ b/src/test/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArraysTest.java
@@ -0,0 +1,41 @@
+package com.thealgorithms.divideandconquer;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class MedianOfTwoSortedArraysTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testFindMedianSortedArrays(int[] nums1, int[] nums2, double expectedMedian) {
+        assertEquals(expectedMedian, MedianOfTwoSortedArrays.findMedianSortedArrays(nums1, nums2));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            // Test case 1: Arrays of equal length
+            Arguments.of(new int[] {1, 3}, new int[] {2, 4}, 2.5),
+
+            // Test case 2: Arrays of different lengths
+            Arguments.of(new int[] {1, 3}, new int[] {2}, 2.0),
+
+            // Test case 3: Arrays with even total length
+            Arguments.of(new int[] {1, 2, 8}, new int[] {3, 4, 5, 6, 7}, 4.5),
+
+            // Test case 4: Arrays with odd total length
+            Arguments.of(new int[] {1, 2, 8}, new int[] {3, 4, 5}, 3.5),
+
+            // Test case 5: Single element arrays
+            Arguments.of(new int[] {1}, new int[] {3}, 2.0),
+
+            // Test case 6: Empty arrays
+            Arguments.of(new int[] {}, new int[] {0}, 0.0),
+
+            // Test case 7: Same element arrays
+            Arguments.of(new int[] {2, 2, 2}, new int[] {2, 2, 2}, 2.0));
+    }
+}

From 4bcab89f0500e6ae97eb09638635662d6344d963 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 9 Oct 2024 12:03:39 +0530
Subject: [PATCH 0469/1338] Add JobSchedulingWithDeadline algorithm (#5608)

---
 DIRECTORY.md                                  |  2 +
 .../scheduling/JobSchedulingWithDeadline.java | 88 +++++++++++++++++++
 .../JobSchedulingWithDeadlineTest.java        | 43 +++++++++
 3 files changed, 133 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index af1e4f284445..a2f65834b498 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -475,6 +475,7 @@
           * scheduling
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
             * [HighestResponseRatioNextScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
+            * [JobSchedulingWithDeadline](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java)
             * [MLFQScheduler](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
@@ -963,6 +964,7 @@
           * scheduling
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
             * [HighestResponseRatioNextSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
+            * [JobSchedulingWithDeadlineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java)
             * [MLFQSchedulerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java b/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java
new file mode 100644
index 000000000000..49638d39fc2a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java
@@ -0,0 +1,88 @@
+package com.thealgorithms.scheduling;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+/**
+ * A class that implements a job scheduling algorithm to maximize profit
+ * while adhering to job deadlines and arrival times.
+ *
+ * This class provides functionality to schedule jobs based on their profit,
+ * arrival time, and deadlines to ensure that the maximum number of jobs is completed
+ * within the given timeframe. It sorts the jobs in decreasing order of profit
+ * and attempts to assign them to the latest possible time slots.
+ */
+public final class JobSchedulingWithDeadline {
+    private JobSchedulingWithDeadline() {
+    }
+
+    /**
+     * Represents a job with an ID, arrival time, deadline, and profit.
+     *
+     * Each job has a unique identifier, an arrival time (when it becomes available for scheduling),
+     * a deadline by which it must be completed, and a profit associated with completing the job.
+     */
+    static class Job {
+        int jobId;
+        int arrivalTime;
+        int deadline;
+        int profit;
+
+        /**
+         * Constructs a Job instance with the specified job ID, arrival time, deadline, and profit.
+         *
+         * @param jobId      Unique identifier for the job
+         * @param arrivalTime Time when the job becomes available for scheduling
+         * @param deadline   Deadline for completing the job
+         * @param profit     Profit earned upon completing the job
+         */
+        Job(int jobId, int arrivalTime, int deadline, int profit) {
+            this.jobId = jobId;
+            this.arrivalTime = arrivalTime;
+            this.deadline = deadline;
+            this.profit = profit;
+        }
+    }
+
+    /**
+     * Schedules jobs to maximize profit while respecting their deadlines and arrival times.
+     *
+     * This method sorts the jobs in descending order of profit and attempts
+     * to allocate them to time slots that are before or on their deadlines,
+     * provided they have arrived. The function returns an array where the first element
+     * is the total number of jobs scheduled and the second element is the total profit earned.
+     *
+     * @param jobs An array of Job objects, each representing a job with an ID, arrival time,
+     *             deadline, and profit.
+     * @return An array of two integers: the first element is the count of jobs
+     *         that were successfully scheduled, and the second element is the
+     *         total profit earned from those jobs.
+     */
+    public static int[] jobSequencingWithDeadlines(Job[] jobs) {
+        Arrays.sort(jobs, Comparator.comparingInt(job -> - job.profit));
+
+        int maxDeadline = Arrays.stream(jobs).mapToInt(job -> job.deadline).max().orElse(0);
+
+        int[] timeSlots = new int[maxDeadline];
+        Arrays.fill(timeSlots, -1);
+
+        int count = 0;
+        int maxProfit = 0;
+
+        // Schedule the jobs
+        for (Job job : jobs) {
+            if (job.arrivalTime <= job.deadline) {
+                for (int i = Math.min(job.deadline - 1, maxDeadline - 1); i >= job.arrivalTime - 1; i--) {
+                    if (timeSlots[i] == -1) {
+                        timeSlots[i] = job.jobId;
+                        count++;
+                        maxProfit += job.profit;
+                        break;
+                    }
+                }
+            }
+        }
+
+        return new int[] {count, maxProfit};
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java b/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java
new file mode 100644
index 000000000000..538db92a1f26
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java
@@ -0,0 +1,43 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+class JobSchedulingWithDeadlineTest {
+
+    @Test
+    void testJobSequencingWithDeadlines1() {
+        JobSchedulingWithDeadline.Job[] jobs = {new JobSchedulingWithDeadline.Job(1, 1, 4, 20), new JobSchedulingWithDeadline.Job(2, 1, 1, 10), new JobSchedulingWithDeadline.Job(3, 1, 1, 40), new JobSchedulingWithDeadline.Job(4, 1, 1, 30)};
+        int[] result = JobSchedulingWithDeadline.jobSequencingWithDeadlines(jobs);
+        assertArrayEquals(new int[] {2, 60}, result); // Expected output: 2 jobs, 60 profit
+    }
+
+    @Test
+    void testJobSequencingWithDeadlines2() {
+        JobSchedulingWithDeadline.Job[] jobs = {new JobSchedulingWithDeadline.Job(1, 1, 2, 100), new JobSchedulingWithDeadline.Job(2, 1, 1, 19), new JobSchedulingWithDeadline.Job(3, 1, 2, 27), new JobSchedulingWithDeadline.Job(4, 1, 1, 25), new JobSchedulingWithDeadline.Job(5, 1, 1, 15)};
+        int[] result = JobSchedulingWithDeadline.jobSequencingWithDeadlines(jobs);
+        assertArrayEquals(new int[] {2, 127}, result); // Expected output: 2 jobs, 127 profit
+    }
+
+    @Test
+    void testJobSequencingWithDeadlinesWithArrivalTimes() {
+        JobSchedulingWithDeadline.Job[] jobs = {new JobSchedulingWithDeadline.Job(1, 2, 5, 50), new JobSchedulingWithDeadline.Job(2, 3, 4, 60), new JobSchedulingWithDeadline.Job(3, 1, 3, 20)};
+        int[] result = JobSchedulingWithDeadline.jobSequencingWithDeadlines(jobs);
+        assertArrayEquals(new int[] {3, 130}, result); // All 3 jobs fit within their deadlines
+    }
+
+    @Test
+    void testJobSequencingWithDeadlinesNoJobs() {
+        JobSchedulingWithDeadline.Job[] jobs = {};
+        int[] result = JobSchedulingWithDeadline.jobSequencingWithDeadlines(jobs);
+        assertArrayEquals(new int[] {0, 0}, result); // No jobs, 0 profit
+    }
+
+    @Test
+    void testJobSequencingWithDeadlinesSingleJob() {
+        JobSchedulingWithDeadline.Job[] jobs = {new JobSchedulingWithDeadline.Job(1, 1, 1, 50)};
+        int[] result = JobSchedulingWithDeadline.jobSequencingWithDeadlines(jobs);
+        assertArrayEquals(new int[] {1, 50}, result); // 1 job scheduled, 50 profit
+    }
+}

From 49a87d3b58142c51e11b669bc5316a9206776202 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 9 Oct 2024 12:38:16 +0530
Subject: [PATCH 0470/1338] Add tests for CountFriendsPairing (#5643)

---
 DIRECTORY.md                                  |  1 +
 .../CountFriendsPairingTest.java              | 50 +++++++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a2f65834b498..fc52f313c3f1 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -785,6 +785,7 @@
             * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
             * [CatalanNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java)
             * [ClimbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java)
+            * [CountFriendsPairingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java)
             * [EditDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java)
             * [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
             * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java
new file mode 100644
index 000000000000..765daba5f69f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java
@@ -0,0 +1,50 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class CountFriendsPairingTest {
+
+    @Test
+    void testSmallCase() {
+        int n = 5;
+        int[] expectedGolombSequence = {1, 2, 2, 3, 3};
+
+        assertTrue(CountFriendsPairing.countFriendsPairing(n, expectedGolombSequence));
+    }
+
+    @Test
+    void testMismatchSequence() {
+        int n = 5;
+        int[] wrongSequence = {1, 2, 2, 2, 3}; // An incorrect sequence
+
+        assertFalse(CountFriendsPairing.countFriendsPairing(n, wrongSequence));
+    }
+
+    @Test
+    void testLargerCase() {
+        int n = 10;
+        int[] expectedGolombSequence = {1, 2, 2, 3, 3, 4, 4, 4, 5, 5};
+
+        assertTrue(CountFriendsPairing.countFriendsPairing(n, expectedGolombSequence));
+    }
+
+    @Test
+    void testEdgeCaseSingleElement() {
+        int n = 1;
+        int[] expectedGolombSequence = {1};
+
+        assertTrue(CountFriendsPairing.countFriendsPairing(n, expectedGolombSequence));
+    }
+
+    @Test
+    void testEmptySequence() {
+        int n = 0;
+        int[] emptySequence = {};
+
+        // Test the case where n is 0 (should handle this gracefully)
+        assertTrue(CountFriendsPairing.countFriendsPairing(n, emptySequence));
+    }
+}

From 0603accfd480cf6ae33daa644ad0b55e9195f578 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 9 Oct 2024 13:39:36 +0530
Subject: [PATCH 0471/1338] Add tests, remove `main` method, improve docs in
 BruteForceKnapsack (#5641)

---
 DIRECTORY.md                                  |  1 +
 .../BruteForceKnapsack.java                   | 76 ++++++++++-----
 .../BruteForceKnapsackTest.java               | 96 +++++++++++++++++++
 3 files changed, 149 insertions(+), 24 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index fc52f313c3f1..70de110e86ea 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -783,6 +783,7 @@
             * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
           * dynamicprogramming
             * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
+            * [BruteForceKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java)
             * [CatalanNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java)
             * [ClimbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java)
             * [CountFriendsPairingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java b/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
index b433c44b9077..3c1851a8c46c 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java
@@ -1,39 +1,67 @@
 package com.thealgorithms.dynamicprogramming;
 
-/* A Naive recursive implementation
-of 0-1 Knapsack problem */
+/**
+ * A naive recursive implementation of the 0-1 Knapsack problem.
+ *
+ * <p>The 0-1 Knapsack problem is a classic optimization problem where you are
+ * given a set of items, each with a weight and a value, and a knapsack with a
+ * fixed capacity. The goal is to determine the maximum value that can be
+ * obtained by selecting a subset of the items such that the total weight does
+ * not exceed the knapsack's capacity. Each item can either be included (1) or
+ * excluded (0), hence the name "0-1" Knapsack.</p>
+ *
+ * <p>This class provides a brute-force recursive approach to solving the
+ * problem. It evaluates all possible combinations of items to find the optimal
+ * solution, but this approach has exponential time complexity and is not
+ * suitable for large input sizes.</p>
+ *
+ * <p><b>Time Complexity:</b> O(2^n), where n is the number of items.</p>
+ *
+ * <p><b>Space Complexity:</b> O(n), due to the recursive function call stack.</p>
+ */
 public final class BruteForceKnapsack {
     private BruteForceKnapsack() {
     }
-    // Returns the maximum value that
-    // can be put in a knapsack of
-    // capacity W
+
+    /**
+     * Solves the 0-1 Knapsack problem using a recursive brute-force approach.
+     *
+     * @param w   the total capacity of the knapsack
+     * @param wt  an array where wt[i] represents the weight of the i-th item
+     * @param val an array where val[i] represents the value of the i-th item
+     * @param n   the number of items available for selection
+     * @return    the maximum value that can be obtained with the given capacity
+     *
+     * <p>The function uses recursion to explore all possible subsets of items.
+     * For each item, it has two choices: either include it in the knapsack
+     * (if it fits) or exclude it. It returns the maximum value obtainable
+     * through these two choices.</p>
+     *
+     * <p><b>Base Cases:</b>
+     * <ul>
+     * <li>If no items are left (n == 0), the maximum value is 0.</li>
+     * <li>If the knapsack's remaining capacity is 0 (w == 0), no more items can
+     * be included, and the value is 0.</li>
+     * </ul></p>
+     *
+     * <p><b>Recursive Steps:</b>
+     * <ul>
+     * <li>If the weight of the n-th item exceeds the current capacity, it is
+     * excluded from the solution, and the function proceeds with the remaining
+     * items.</li>
+     * <li>Otherwise, the function considers two possibilities: include the n-th
+     * item or exclude it, and returns the maximum value of these two scenarios.</li>
+     * </ul></p>
+     */
     static int knapSack(int w, int[] wt, int[] val, int n) {
-        // Base Case
         if (n == 0 || w == 0) {
             return 0;
         }
 
-        // If weight of the nth item is
-        // more than Knapsack capacity W,
-        // then this item cannot be included
-        // in the optimal solution
         if (wt[n - 1] > w) {
             return knapSack(w, wt, val, n - 1);
-        } // Return the maximum of two cases:
-        // (1) nth item included
-        // (2) not included
-        else {
-            return Math.max(val[n - 1] + knapSack(w - wt[n - 1], wt, val, n - 1), knapSack(w, wt, val, n - 1));
+        } else {
+            return Math.max(knapSack(w, wt, val, n - 1), val[n - 1] + knapSack(w - wt[n - 1], wt, val, n - 1));
         }
     }
-
-    // Driver code
-    public static void main(String[] args) {
-        int[] val = new int[] {60, 100, 120};
-        int[] wt = new int[] {10, 20, 30};
-        int w = 50;
-        int n = val.length;
-        System.out.println(knapSack(w, wt, val, n));
-    }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java
new file mode 100644
index 000000000000..ef96f16e04f7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java
@@ -0,0 +1,96 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class BruteForceKnapsackTest {
+
+    @Test
+    void testKnapSackBasicCase() {
+        int[] val = {60, 100, 120};
+        int[] wt = {10, 20, 30};
+        int w = 50;
+        int n = val.length;
+
+        // The expected result for this case is 220 (items 2 and 3 are included)
+        assertEquals(220, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackNoItems() {
+        int[] val = {};
+        int[] wt = {};
+        int w = 50;
+        int n = val.length;
+
+        // With no items, the maximum value should be 0
+        assertEquals(0, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackZeroCapacity() {
+        int[] val = {60, 100, 120};
+        int[] wt = {10, 20, 30};
+        int w = 0;
+        int n = val.length;
+
+        // With a knapsack of 0 capacity, no items can be included, so the value is 0
+        assertEquals(0, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackSingleItemFits() {
+        int[] val = {100};
+        int[] wt = {20};
+        int w = 30;
+        int n = val.length;
+
+        // Only one item, and it fits in the knapsack, so the result is 100
+        assertEquals(100, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackSingleItemDoesNotFit() {
+        int[] val = {100};
+        int[] wt = {20};
+        int w = 10;
+        int n = val.length;
+
+        // Single item does not fit in the knapsack, so the result is 0
+        assertEquals(0, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackAllItemsFit() {
+        int[] val = {20, 30, 40};
+        int[] wt = {1, 2, 3};
+        int w = 6;
+        int n = val.length;
+
+        // All items fit into the knapsack, so the result is the sum of all values (20 + 30 + 40 = 90)
+        assertEquals(90, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackNoneFit() {
+        int[] val = {100, 200, 300};
+        int[] wt = {100, 200, 300};
+        int w = 50;
+        int n = val.length;
+
+        // None of the items fit into the knapsack, so the result is 0
+        assertEquals(0, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackSomeItemsFit() {
+        int[] val = {60, 100, 120};
+        int[] wt = {10, 20, 30};
+        int w = 40;
+        int n = val.length;
+
+        // Here, only the 2nd and 1st items should be included for a total value of 160
+        assertEquals(180, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+}

From 2d34bc150fe2e3a64bb750ed1174dac9e96bf46b Mon Sep 17 00:00:00 2001
From: Sanketh L Reddy <97825819+sankethl27@users.noreply.github.com>
Date: Wed, 9 Oct 2024 19:27:11 +0530
Subject: [PATCH 0472/1338] Optimised Space Complexity To O(sum) (#5651)

* Optimised Space Complexity To O(sum)

* Fixes Clang Format

* Optimised Space Complexity To Use a Single DP Array
---
 .../dynamicprogramming/SubsetSum.java         | 29 +++++++++----------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java
index 3dd41d2fdc0f..da8667afd0ce 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java
@@ -9,28 +9,25 @@ private SubsetSum() {
      *
      * @param arr the array containing integers.
      * @param sum the target sum of the subset.
-     * @return {@code true} if a subset exists that sums to the given value, otherwise {@code false}.
+     * @return {@code true} if a subset exists that sums to the given value,
+     *         otherwise {@code false}.
      */
     public static boolean subsetSum(int[] arr, int sum) {
         int n = arr.length;
-        boolean[][] isSum = new boolean[n + 1][sum + 1];
 
-        // Initialize the first column to true since a sum of 0 can always be achieved with an empty subset.
-        for (int i = 0; i <= n; i++) {
-            isSum[i][0] = true;
-        }
+        // Initialize a single array to store the possible sums
+        boolean[] isSum = new boolean[sum + 1];
+
+        // Mark isSum[0] = true since a sum of 0 is always possible with 0 elements
+        isSum[0] = true;
 
-        // Fill the subset sum matrix
-        for (int i = 1; i <= n; i++) {
-            for (int j = 1; j <= sum; j++) {
-                if (arr[i - 1] <= j) {
-                    isSum[i][j] = isSum[i - 1][j] || isSum[i - 1][j - arr[i - 1]];
-                } else {
-                    isSum[i][j] = isSum[i - 1][j];
-                }
+        // Iterate through each Element in the array
+        for (int i = 0; i < n; i++) {
+            // Traverse the isSum array backwards to prevent overwriting values
+            for (int j = sum; j >= arr[i]; j--) {
+                isSum[j] = isSum[j] || isSum[j - arr[i]];
             }
         }
-
-        return isSum[n][sum];
+        return isSum[sum];
     }
 }

From 6ddb26f48d79b983a3f8f2509fae4c67aef612f7 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 10 Oct 2024 00:34:04 +0530
Subject: [PATCH 0473/1338] Add tests, remove `main` & `print` methods in
 `CoinChange.java` (#5642)

---
 DIRECTORY.md                                  |  1 +
 .../dynamicprogramming/CoinChange.java        | 22 +----
 .../dynamicprogramming/CoinChangeTest.java    | 80 +++++++++++++++++++
 3 files changed, 82 insertions(+), 21 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/CoinChangeTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 70de110e86ea..0c235b792083 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -786,6 +786,7 @@
             * [BruteForceKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java)
             * [CatalanNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java)
             * [ClimbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java)
+            * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CoinChangeTest.java)
             * [CountFriendsPairingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java)
             * [EditDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java)
             * [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java b/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java
index 12cc29faa923..7edc9603dc8b 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java
@@ -7,15 +7,6 @@ public final class CoinChange {
     private CoinChange() {
     }
 
-    // Driver Program
-    public static void main(String[] args) {
-        int amount = 12;
-        int[] coins = {2, 4, 5};
-
-        System.out.println("Number of combinations of getting change for " + amount + " is: " + change(coins, amount));
-        System.out.println("Minimum number of coins required for amount :" + amount + " is: " + minimumCoins(coins, amount));
-    }
-
     /**
      * This method finds the number of combinations of getting change for a
      * given amount and change coins
@@ -32,8 +23,6 @@ public static int change(int[] coins, int amount) {
             for (int i = coin; i < amount + 1; i++) {
                 combinations[i] += combinations[i - coin];
             }
-            // Uncomment the below line to see the state of combinations for each coin
-            // printAmount(combinations);
         }
 
         return combinations[amount];
@@ -65,16 +54,7 @@ public static int minimumCoins(int[] coins, int amount) {
                 }
             }
         }
-        // Uncomment the below line to see the state of combinations for each coin
-        // printAmount(minimumCoins);
-        return minimumCoins[amount];
-    }
 
-    // A basic print method which prints all the contents of the array
-    public static void printAmount(int[] arr) {
-        for (int i = 0; i < arr.length; i++) {
-            System.out.print(arr[i] + " ");
-        }
-        System.out.println();
+        return minimumCoins[amount];
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/CoinChangeTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/CoinChangeTest.java
new file mode 100644
index 000000000000..10bc6600ae1e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/CoinChangeTest.java
@@ -0,0 +1,80 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class CoinChangeTest {
+
+    @Test
+    void testChangeBasic() {
+        int amount = 12;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(5, CoinChange.change(coins, amount));
+    }
+
+    @Test
+    void testChangeNoCoins() {
+        int amount = 12;
+        int[] coins = {};
+
+        assertEquals(0, CoinChange.change(coins, amount));
+    }
+
+    @Test
+    void testChangeNoAmount() {
+        int amount = 0;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(1, CoinChange.change(coins, amount));
+    }
+
+    @Test
+    void testChangeImpossibleAmount() {
+        int amount = 3;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(0, CoinChange.change(coins, amount));
+    }
+
+    @Test
+    void testMinimumCoinsBasic() {
+        int amount = 12;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(3, CoinChange.minimumCoins(coins, amount));
+    }
+
+    @Test
+    void testMinimumCoinsNoCoins() {
+        int amount = 12;
+        int[] coins = {};
+
+        assertEquals(Integer.MAX_VALUE, CoinChange.minimumCoins(coins, amount));
+    }
+
+    @Test
+    void testMinimumCoinsNoAmount() {
+        int amount = 0;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(0, CoinChange.minimumCoins(coins, amount));
+    }
+
+    @Test
+    void testMinimumCoinsImpossibleAmount() {
+        int amount = 3;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(Integer.MAX_VALUE, CoinChange.minimumCoins(coins, amount));
+    }
+
+    @Test
+    void testMinimumCoinsExactAmount() {
+        int amount = 10;
+        int[] coins = {1, 5, 10};
+
+        assertEquals(1, CoinChange.minimumCoins(coins, amount));
+    }
+}

From 4a0e46dae6ce49eca6f592cb0ea23054eff2bfa1 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 10 Oct 2024 00:46:20 +0530
Subject: [PATCH 0474/1338] Add tests, remove `main` in `DiceThrow/DP.java`
 (#5644)

---
 DIRECTORY.md                                  |  1 +
 .../dynamicprogramming/DiceThrow.java         | 18 +-----
 .../dynamicprogramming/DPTest.java            | 56 +++++++++++++++++++
 3 files changed, 58 insertions(+), 17 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/DPTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0c235b792083..520e7b332d3c 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -788,6 +788,7 @@
             * [ClimbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java)
             * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CoinChangeTest.java)
             * [CountFriendsPairingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java)
+            * [DPTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/DPTest.java)
             * [EditDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java)
             * [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
             * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java b/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java
index e1be3ead5895..c3dc3f32ff7c 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java
@@ -9,6 +9,7 @@
 
 /* Hence, storing the results of the solved sub-problems saves time.
 And it can be done using Dynamic Programming(DP).
+// Time Complexity: O(m * n * x) where m is number of faces, n is number of dice and x is given sum.
 Following is implementation of Dynamic Programming approach. */
 // Code ---->
 // Java program to find number of ways to get sum 'x' with 'n'
@@ -43,21 +44,4 @@ public static long findWays(int m, int n, int x) {
 
         return table[n][x];
     }
-
-    public static void main(String[] args) {
-        System.out.println(findWays(4, 2, 1));
-        System.out.println(findWays(2, 2, 3));
-        System.out.println(findWays(6, 3, 8));
-        System.out.println(findWays(4, 2, 5));
-        System.out.println(findWays(4, 3, 5));
-    }
 }
-/*
-OUTPUT:
-0
-2
-21
-4
-6
- */
-// Time Complexity: O(m * n * x) where m is number of faces, n is number of dice and x is given sum.
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/DPTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/DPTest.java
new file mode 100644
index 000000000000..e3bea67fe269
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/DPTest.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class DPTest {
+
+    @Test
+    void testSumLessThanMinimumFaceValue() {
+        // When the sum is less than the minimum possible face value
+        // There are 0 ways to achieve the sum
+        assertEquals(0, DP.findWays(4, 2, 1)); // 4 faces, 2 dice, sum = 1
+    }
+
+    @Test
+    void testTwoDiceWithSumEqualToTwo() {
+        // When there are 2 dice and the sum is equal to the number of dice
+        // The only way is to have both dice showing 1
+        assertEquals(1, DP.findWays(2, 2, 2)); // 2 faces, 2 dice, sum = 2
+    }
+
+    @Test
+    void testTwoDiceWithSumThree() {
+        // When there are 2 dice and the sum is equal to 3
+        // Possible combinations are (1,2) and (2,1)
+        assertEquals(2, DP.findWays(2, 2, 3)); // 2 faces, 2 dice, sum = 3
+    }
+
+    @Test
+    void testThreeDiceWithSumEight() {
+        // Test for 3 dice, each having 6 faces
+        // Possible combinations to make sum of 8
+        assertEquals(21, DP.findWays(6, 3, 8)); // 6 faces, 3 dice, sum = 8
+    }
+
+    @Test
+    void testTwoDiceWithSumFive() {
+        // Test for 2 dice, with 4 faces to make sum of 5
+        // Possible combinations: (1,4), (2,3), (3,2), (4,1)
+        assertEquals(4, DP.findWays(4, 2, 5)); // 4 faces, 2 dice, sum = 5
+    }
+
+    @Test
+    void testThreeDiceWithSumFive() {
+        // Test for 3 dice, with 4 faces to make sum of 5
+        // Possible combinations: (1,1,3), (1,2,2), (1,3,1), (2,1,2), (2,2,1), (3,1,1)
+        assertEquals(6, DP.findWays(4, 3, 5)); // 4 faces, 3 dice, sum = 5
+    }
+
+    @Test
+    void testEdgeCaseZeroSum() {
+        // Test for 0 sum with 0 dice
+        assertEquals(0, DP.findWays(4, 0, 0)); // 4 faces, 0 dice, sum = 0
+    }
+}

From ce9f42081d3997e0ea7b6cc22ff52f3aacaf2db3 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 10 Oct 2024 00:50:45 +0530
Subject: [PATCH 0475/1338] Add tests, remove `main`, add negativity test in
 `Fibonacci.java` (#5645)

---
 DIRECTORY.md                                  |  1 +
 .../dynamicprogramming/Fibonacci.java         | 34 +++----
 .../dynamicprogramming/FibonacciTest.java     | 89 +++++++++++++++++++
 3 files changed, 109 insertions(+), 15 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/FibonacciTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 520e7b332d3c..94f5890bb157 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -791,6 +791,7 @@
             * [DPTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/DPTest.java)
             * [EditDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java)
             * [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
+            * [FibonacciTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/FibonacciTest.java)
             * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
             * [KnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
             * [LevenshteinDistanceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
index 5855030fc65c..0d6aff2bbef3 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
@@ -2,7 +2,6 @@
 
 import java.util.HashMap;
 import java.util.Map;
-import java.util.Scanner;
 
 /**
  * @author Varun Upadhyay (https://github.com/varunu28)
@@ -11,27 +10,19 @@ public final class Fibonacci {
     private Fibonacci() {
     }
 
-    private static final Map<Integer, Integer> CACHE = new HashMap<>();
-
-    public static void main(String[] args) {
-        // Methods all returning [0, 1, 1, 2, 3, 5, ...] for n = [0, 1, 2, 3, 4, 5, ...]
-        Scanner sc = new Scanner(System.in);
-        int n = sc.nextInt();
-
-        System.out.println(fibMemo(n));
-        System.out.println(fibBotUp(n));
-        System.out.println(fibOptimized(n));
-        System.out.println(fibBinet(n));
-        sc.close();
-    }
+    static final Map<Integer, Integer> CACHE = new HashMap<>();
 
     /**
      * This method finds the nth fibonacci number using memoization technique
      *
      * @param n The input n for which we have to determine the fibonacci number
      * Outputs the nth fibonacci number
+     * @throws IllegalArgumentException if n is negative
      */
     public static int fibMemo(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input n must be non-negative");
+        }
         if (CACHE.containsKey(n)) {
             return CACHE.get(n);
         }
@@ -52,8 +43,12 @@ public static int fibMemo(int n) {
      *
      * @param n The input n for which we have to determine the fibonacci number
      * Outputs the nth fibonacci number
+     * @throws IllegalArgumentException if n is negative
      */
     public static int fibBotUp(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input n must be non-negative");
+        }
         Map<Integer, Integer> fib = new HashMap<>();
 
         for (int i = 0; i <= n; i++) {
@@ -80,9 +75,13 @@ public static int fibBotUp(int n) {
      * Time Complexity will be O(n)
      * <p>
      * Whereas , the above functions will take O(n) Space.
+     * @throws IllegalArgumentException if n is negative
      * @author Shoaib Rayeen (https://github.com/shoaibrayeen)
      */
     public static int fibOptimized(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input n must be non-negative");
+        }
         if (n == 0) {
             return 0;
         }
@@ -105,9 +104,14 @@ public static int fibOptimized(int n) {
      * = 1.6180339887... Now, let's look at Binet's formula: Sn = Φⁿ–(– Φ⁻ⁿ)/√5 We first calculate
      * the squareRootof5 and phi and store them in variables. Later, we apply Binet's formula to get
      * the required term. Time Complexity will be O(1)
+     * @param n The input n for which we have to determine the fibonacci number
+     * Outputs the nth fibonacci number
+     * @throws IllegalArgumentException if n is negative
      */
-
     public static int fibBinet(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input n must be non-negative");
+        }
         double squareRootOf5 = Math.sqrt(5);
         double phi = (1 + squareRootOf5) / 2;
         return (int) ((Math.pow(phi, n) - Math.pow(-phi, -n)) / squareRootOf5);
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/FibonacciTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/FibonacciTest.java
new file mode 100644
index 000000000000..166e20c3083f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/FibonacciTest.java
@@ -0,0 +1,89 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class FibonacciTest {
+
+    @BeforeEach
+    void setUp() {
+        // Clear the cache before each test to avoid interference
+        Fibonacci.CACHE.clear();
+    }
+
+    @Test
+    void testFibMemo() {
+        // Test memoization method
+        assertEquals(0, Fibonacci.fibMemo(0));
+        assertEquals(1, Fibonacci.fibMemo(1));
+        assertEquals(1, Fibonacci.fibMemo(2));
+        assertEquals(2, Fibonacci.fibMemo(3));
+        assertEquals(3, Fibonacci.fibMemo(4));
+        assertEquals(5, Fibonacci.fibMemo(5));
+        assertEquals(8, Fibonacci.fibMemo(6));
+        assertEquals(13, Fibonacci.fibMemo(7));
+        assertEquals(21, Fibonacci.fibMemo(8));
+        assertEquals(34, Fibonacci.fibMemo(9));
+        assertEquals(55, Fibonacci.fibMemo(10));
+    }
+
+    @Test
+    void testFibBotUp() {
+        // Test bottom-up method
+        assertEquals(0, Fibonacci.fibBotUp(0));
+        assertEquals(1, Fibonacci.fibBotUp(1));
+        assertEquals(1, Fibonacci.fibBotUp(2));
+        assertEquals(2, Fibonacci.fibBotUp(3));
+        assertEquals(3, Fibonacci.fibBotUp(4));
+        assertEquals(5, Fibonacci.fibBotUp(5));
+        assertEquals(8, Fibonacci.fibBotUp(6));
+        assertEquals(13, Fibonacci.fibBotUp(7));
+        assertEquals(21, Fibonacci.fibBotUp(8));
+        assertEquals(34, Fibonacci.fibBotUp(9));
+        assertEquals(55, Fibonacci.fibBotUp(10));
+    }
+
+    @Test
+    void testFibOptimized() {
+        // Test optimized Fibonacci method
+        assertEquals(0, Fibonacci.fibOptimized(0));
+        assertEquals(1, Fibonacci.fibOptimized(1));
+        assertEquals(1, Fibonacci.fibOptimized(2));
+        assertEquals(2, Fibonacci.fibOptimized(3));
+        assertEquals(3, Fibonacci.fibOptimized(4));
+        assertEquals(5, Fibonacci.fibOptimized(5));
+        assertEquals(8, Fibonacci.fibOptimized(6));
+        assertEquals(13, Fibonacci.fibOptimized(7));
+        assertEquals(21, Fibonacci.fibOptimized(8));
+        assertEquals(34, Fibonacci.fibOptimized(9));
+        assertEquals(55, Fibonacci.fibOptimized(10));
+    }
+
+    @Test
+    void testFibBinet() {
+        // Test Binet's formula method
+        assertEquals(0, Fibonacci.fibBinet(0));
+        assertEquals(1, Fibonacci.fibBinet(1));
+        assertEquals(1, Fibonacci.fibBinet(2));
+        assertEquals(2, Fibonacci.fibBinet(3));
+        assertEquals(3, Fibonacci.fibBinet(4));
+        assertEquals(5, Fibonacci.fibBinet(5));
+        assertEquals(8, Fibonacci.fibBinet(6));
+        assertEquals(13, Fibonacci.fibBinet(7));
+        assertEquals(21, Fibonacci.fibBinet(8));
+        assertEquals(34, Fibonacci.fibBinet(9));
+        assertEquals(55, Fibonacci.fibBinet(10));
+    }
+
+    @Test
+    void testNegativeInput() {
+        // Test negative input; Fibonacci is not defined for negative numbers
+        assertThrows(IllegalArgumentException.class, () -> { Fibonacci.fibMemo(-1); });
+        assertThrows(IllegalArgumentException.class, () -> { Fibonacci.fibBotUp(-1); });
+        assertThrows(IllegalArgumentException.class, () -> { Fibonacci.fibOptimized(-1); });
+        assertThrows(IllegalArgumentException.class, () -> { Fibonacci.fibBinet(-1); });
+    }
+}

From 029dd85646b3ca1d3f827552a56f873221f4a246 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 10 Oct 2024 01:06:00 +0530
Subject: [PATCH 0476/1338] Add tests, enhance docs in `KadaneAlgorithm.java`
 (#5646)

---
 DIRECTORY.md                                  |  1 +
 .../dynamicprogramming/KadaneAlgorithm.java   | 44 ++++++++-----
 .../KadaneAlgorithmTest.java                  | 61 +++++++++++++++++++
 3 files changed, 92 insertions(+), 14 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithmTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 94f5890bb157..2b595e7a6652 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -792,6 +792,7 @@
             * [EditDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java)
             * [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
             * [FibonacciTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/FibonacciTest.java)
+            * [KadaneAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithmTest.java)
             * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
             * [KnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
             * [LevenshteinDistanceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
index 905815d10a29..7a0a3da94c1e 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java
@@ -1,36 +1,52 @@
 package com.thealgorithms.dynamicprogramming;
 
 /**
- * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
- * Program description - To find the maximum subarray sum
+ * This class implements Kadane's Algorithm to find the maximum subarray sum
+ * within a given array of integers. The algorithm efficiently computes the maximum
+ * sum of a contiguous subarray in linear time.
+ *
+ * Author: <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
  */
 public final class KadaneAlgorithm {
     private KadaneAlgorithm() {
     }
 
     /**
-     * OUTPUT :
-     * Input - {89,56,98,123,26,75,12,40,39,68,91}
-     * Output: it returns either true or false
-     * 1st approach Time Complexity : O(n)
-     * Auxiliary Space Complexity : O(1)
+     * Computes the maximum subarray sum using Kadane's Algorithm and checks
+     * if it matches a predicted answer.
+     *
+     * @param a              The input array of integers for which the maximum
+     *                       subarray sum is to be calculated.
+     * @param predictedAnswer The expected maximum subarray sum to be verified
+     *                       against the computed sum.
+     * @return true if the computed maximum subarray sum equals the predicted
+     *         answer, false otherwise.
+     *
+     * <p>Example:</p>
+     * <pre>
+     * Input: {89, 56, 98, 123, 26, 75, 12, 40, 39, 68, 91}
+     * Output: true if the maximum subarray sum is equal to the
+     *         predicted answer.
+     * </pre>
+     *
+     * <p>Algorithmic Complexity:</p>
+     * <ul>
+     * <li>Time Complexity: O(n) - the algorithm iterates through the array once.</li>
+     * <li>Auxiliary Space Complexity: O(1) - only a constant amount of additional space is used.</li>
+     * </ul>
      */
     public static boolean maxSum(int[] a, int predictedAnswer) {
         int sum = a[0];
         int runningSum = 0;
+
         for (int k : a) {
-            runningSum = runningSum + k;
-            // running sum of all the indexs are stored
+            runningSum += k;
             sum = Math.max(sum, runningSum);
-            // the max is stored inorder to the get the maximum sum
             if (runningSum < 0) {
                 runningSum = 0;
             }
-            // if running sum is negative then it is initialized to zero
         }
-        // for-each loop is used to iterate over the array and find the maximum subarray sum
+
         return sum == predictedAnswer;
-        // It returns true if sum and predicted answer matches
-        // The predicted answer is the answer itself. So it always return true
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithmTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithmTest.java
new file mode 100644
index 000000000000..e26606ef98a9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithmTest.java
@@ -0,0 +1,61 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class KadaneAlgorithmTest {
+
+    @Test
+    void testMaxSumWithPositiveValues() {
+        // Test with all positive numbers
+        int[] input = {89, 56, 98, 123, 26, 75, 12, 40, 39, 68, 91};
+        int expectedMaxSum = 89 + 56 + 98 + 123 + 26 + 75 + 12 + 40 + 39 + 68 + 91; // sum of all elements
+        assertTrue(KadaneAlgorithm.maxSum(input, expectedMaxSum));
+    }
+
+    @Test
+    void testMaxSumWithMixedValues() {
+        // Test with mixed positive and negative numbers
+        int[] input = {1, -2, 3, 4, -1, 2, 1, -5, 4};
+        int expectedMaxSum = 3 + 4 + -1 + 2 + 1; // max subarray is [3, 4, -1, 2, 1]
+        assertTrue(KadaneAlgorithm.maxSum(input, expectedMaxSum));
+    }
+
+    @Test
+    void testMaxSumWithAllNegativeValues() {
+        // Test with all negative numbers
+        int[] input = {-2, -3, -1, -4};
+        int expectedMaxSum = -1; // max subarray is the least negative number
+        assertTrue(KadaneAlgorithm.maxSum(input, expectedMaxSum));
+    }
+
+    @Test
+    void testMaxSumWithSingleElement() {
+        // Test with a single positive element
+        int[] input = {10};
+        int expectedMaxSum = 10; // max subarray is the single element
+        assertTrue(KadaneAlgorithm.maxSum(input, expectedMaxSum));
+
+        // Test with a single negative element
+        input = new int[] {-10};
+        expectedMaxSum = -10; // max subarray is the single element
+        assertTrue(KadaneAlgorithm.maxSum(input, expectedMaxSum));
+    }
+
+    @Test
+    void testMaxSumWithZero() {
+        // Test with zeros in the array
+        int[] input = {0, -1, 2, -2, 0, 3};
+        int expectedMaxSum = 3; // max subarray is [2, -2, 0, 3]
+        assertTrue(KadaneAlgorithm.maxSum(input, expectedMaxSum));
+    }
+
+    @Test
+    void testMaxSumWithEmptyArray() {
+        // Test with an empty array; should ideally throw an exception or return false
+        int[] input = {};
+        assertThrows(ArrayIndexOutOfBoundsException.class, () -> { KadaneAlgorithm.maxSum(input, 0); });
+    }
+}

From 6e6028e3d0c96d30dc274866bd5398c5cddd0f5f Mon Sep 17 00:00:00 2001
From: SAIVARDHAN15 <127930279+SAIVARDHAN15@users.noreply.github.com>
Date: Thu, 10 Oct 2024 01:11:25 +0530
Subject: [PATCH 0477/1338] Fix columnarTranspositionCipher and typos in Test
 (#5649)

---
 .../ciphers/ColumnarTranspositionCipher.java  | 29 +++++++++----------
 .../ColumnarTranspositionCipherTest.java      | 14 ++++-----
 2 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java b/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java
index d7e64a12ebfd..b6b889b079ca 100644
--- a/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java
@@ -27,13 +27,13 @@ private ColumnarTranspositionCipher() {
      * @return a String with the word encrypted by the Columnar Transposition
      * Cipher Rule
      */
-    public static String encrpyter(String word, String keyword) {
+    public static String encrypt(final String word, final String keyword) {
         ColumnarTranspositionCipher.keyword = keyword;
-        abecedariumBuilder(500);
+        abecedariumBuilder();
         table = tableBuilder(word);
         Object[][] sortedTable = sortTable(table);
         StringBuilder wordEncrypted = new StringBuilder();
-        for (int i = 0; i < sortedTable[i].length; i++) {
+        for (int i = 0; i < sortedTable[0].length; i++) {
             for (int j = 1; j < sortedTable.length; j++) {
                 wordEncrypted.append(sortedTable[j][i]);
             }
@@ -51,11 +51,12 @@ public static String encrpyter(String word, String keyword) {
      * @return a String with the word encrypted by the Columnar Transposition
      * Cipher Rule
      */
-    public static String encrpyter(String word, String keyword, String abecedarium) {
+    public static String encrypt(String word, String keyword, String abecedarium) {
         ColumnarTranspositionCipher.keyword = keyword;
         ColumnarTranspositionCipher.abecedarium = Objects.requireNonNullElse(abecedarium, ABECEDARIUM);
         table = tableBuilder(word);
         Object[][] sortedTable = sortTable(table);
+
         StringBuilder wordEncrypted = new StringBuilder();
         for (int i = 0; i < sortedTable[0].length; i++) {
             for (int j = 1; j < sortedTable.length; j++) {
@@ -72,7 +73,7 @@ public static String encrpyter(String word, String keyword, String abecedarium)
      * @return a String decrypted with the word encrypted by the Columnar
      * Transposition Cipher Rule
      */
-    public static String decrypter() {
+    public static String decrypt() {
         StringBuilder wordDecrypted = new StringBuilder();
         for (int i = 1; i < table.length; i++) {
             for (Object item : table[i]) {
@@ -91,14 +92,14 @@ public static String decrypter() {
      */
     private static Object[][] tableBuilder(String word) {
         Object[][] table = new Object[numberOfRows(word) + 1][keyword.length()];
-        char[] wordInChards = word.toCharArray();
-        // Fils in the respective numbers
+        char[] wordInChars = word.toCharArray();
+        // Fills in the respective numbers for the column
         table[0] = findElements();
         int charElement = 0;
         for (int i = 1; i < table.length; i++) {
             for (int j = 0; j < table[i].length; j++) {
-                if (charElement < wordInChards.length) {
-                    table[i][j] = wordInChards[charElement];
+                if (charElement < wordInChars.length) {
+                    table[i][j] = wordInChars[charElement];
                     charElement++;
                 } else {
                     table[i][j] = ENCRYPTION_FIELD_CHAR;
@@ -116,7 +117,7 @@ private static Object[][] tableBuilder(String word) {
      * order to respect the Columnar Transposition Cipher Rule.
      */
     private static int numberOfRows(String word) {
-        if (word.length() / keyword.length() > word.length() / keyword.length()) {
+        if (word.length() % keyword.length() != 0) {
             return (word.length() / keyword.length()) + 1;
         } else {
             return word.length() / keyword.length();
@@ -173,13 +174,11 @@ private static void switchColumns(Object[][] table, int firstColumnIndex, int se
     }
 
     /**
-     * Creates an abecedarium with a specified ascii inded
-     *
-     * @param value Number of characters being used based on the ASCII Table
+     * Creates an abecedarium with all available ascii values.
      */
-    private static void abecedariumBuilder(int value) {
+    private static void abecedariumBuilder() {
         StringBuilder t = new StringBuilder();
-        for (int i = 0; i < value; i++) {
+        for (int i = 0; i < 256; i++) {
             t.append((char) i);
         }
         abecedarium = t.toString();
diff --git a/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java b/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java
index 0d306a6623db..8deae45099d6 100644
--- a/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java
@@ -20,7 +20,7 @@ public void setUp() {
 
     @Test
     public void testEncryption() {
-        String encryptedText = ColumnarTranspositionCipher.encrpyter(plaintext, keyword);
+        String encryptedText = ColumnarTranspositionCipher.encrypt(plaintext, keyword);
         assertNotNull(encryptedText, "The encrypted text should not be null.");
         assertFalse(encryptedText.isEmpty(), "The encrypted text should not be empty.");
         // Check if the encrypted text is different from the plaintext
@@ -29,19 +29,19 @@ public void testEncryption() {
 
     @Test
     public void testDecryption() {
-        String encryptedText = ColumnarTranspositionCipher.encrpyter(plaintext, keyword);
-        String decryptedText = ColumnarTranspositionCipher.decrypter();
+        String encryptedText = ColumnarTranspositionCipher.encrypt(plaintext, keyword);
+        String decryptedText = ColumnarTranspositionCipher.decrypt();
 
         assertEquals(plaintext.replaceAll(" ", ""), decryptedText.replaceAll(" ", ""), "The decrypted text should match the original plaintext, ignoring spaces.");
-        assertEquals(encryptedText, ColumnarTranspositionCipher.encrpyter(plaintext, keyword), "The encrypted text should be the same when encrypted again.");
+        assertEquals(encryptedText, ColumnarTranspositionCipher.encrypt(plaintext, keyword), "The encrypted text should be the same when encrypted again.");
     }
 
     @Test
     public void testLongPlainText() {
         String longText = "This is a significantly longer piece of text to test the encryption and decryption capabilities of the Columnar Transposition Cipher. It should handle long strings gracefully.";
-        String encryptedText = ColumnarTranspositionCipher.encrpyter(longText, keyword);
-        String decryptedText = ColumnarTranspositionCipher.decrypter();
+        String encryptedText = ColumnarTranspositionCipher.encrypt(longText, keyword);
+        String decryptedText = ColumnarTranspositionCipher.decrypt();
         assertEquals(longText.replaceAll(" ", ""), decryptedText.replaceAll(" ", ""), "The decrypted text should match the original long plaintext, ignoring spaces.");
-        assertEquals(encryptedText, ColumnarTranspositionCipher.encrpyter(longText, keyword), "The encrypted text should be the same when encrypted again.");
+        assertEquals(encryptedText, ColumnarTranspositionCipher.encrypt(longText, keyword), "The encrypted text should be the same when encrypted again.");
     }
 }

From f170078b8bb1ec346b574b86601040267f2cb2a8 Mon Sep 17 00:00:00 2001
From: Abhinay Verma <53249427+Monk-AbhinayVerma@users.noreply.github.com>
Date: Thu, 10 Oct 2024 01:15:15 +0530
Subject: [PATCH 0478/1338] Add Ones & Twos Complement in BitManipulation
 (#5604)

---
 .../bitmanipulation/OnesComplement.java       | 28 ++++++++++
 .../bitmanipulation/TwosComplement.java       | 41 ++++++++++++++
 .../bitmanipulation/OnesComplementTest.java   | 47 ++++++++++++++++
 .../bitmanipulation/TwosComplementTest.java   | 54 +++++++++++++++++++
 4 files changed, 170 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java b/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java
new file mode 100644
index 000000000000..c5c068422113
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * @author - https://github.com/Monk-AbhinayVerma
+ * @Wikipedia - https://en.wikipedia.org/wiki/Ones%27_complement
+ *            The class OnesComplement computes the complement of binary number
+ *            and returns
+ *            the complemented binary string.
+ * @return the complimented binary string
+ */
+public final class OnesComplement {
+    private OnesComplement() {
+    }
+
+    // Function to get the 1's complement of a binary number
+    public static String onesComplement(String binary) {
+        StringBuilder complement = new StringBuilder();
+        // Invert each bit to get the 1's complement
+        for (int i = 0; i < binary.length(); i++) {
+            if (binary.charAt(i) == '0') {
+                complement.append('1');
+            } else {
+                complement.append('0');
+            }
+        }
+        return complement.toString();
+    }
+}
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java b/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java
new file mode 100644
index 000000000000..0bc200722943
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java
@@ -0,0 +1,41 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * @wikipedia - https://en.wikipedia.org/wiki/Two%27s_complement
+ *            This Algorithm was first suggested by Jon Von Neumann
+ * @author - https://github.com/Monk-AbhinayVerma
+ * @return the two's complement of any binary number
+ */
+public final class TwosComplement {
+    private TwosComplement() {
+    }
+
+    // Function to get the 2's complement of a binary number
+    public static String twosComplement(String binary) {
+        StringBuilder onesComplement = new StringBuilder();
+        // Step 1: Find the 1's complement (invert the bits)
+        for (int i = 0; i < binary.length(); i++) {
+            if (binary.charAt(i) == '0') {
+                onesComplement.append('1');
+            } else {
+                onesComplement.append('0');
+            }
+        }
+        // Step 2: Add 1 to the 1's complement
+        StringBuilder twosComplement = new StringBuilder(onesComplement);
+        boolean carry = true;
+        for (int i = onesComplement.length() - 1; i >= 0; i--) {
+            if (onesComplement.charAt(i) == '1' && carry) {
+                twosComplement.setCharAt(i, '0');
+            } else if (onesComplement.charAt(i) == '0' && carry) {
+                twosComplement.setCharAt(i, '1');
+                carry = false;
+            }
+        }
+        // If there is still a carry, append '1' at the beginning
+        if (carry) {
+            twosComplement.insert(0, '1');
+        }
+        return twosComplement.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java b/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java
new file mode 100644
index 000000000000..6be4eb595f79
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java
@@ -0,0 +1,47 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test case for Highest Set Bit
+ * @author Abhinay Verma(https://github.com/Monk-AbhinayVerma)
+ */
+public class OnesComplementTest {
+
+    @Test
+    public void testOnesComplementAllZeroes() {
+
+        // Test cases with all-zero binary strings
+        assertEquals("1111", OnesComplement.onesComplement("0000"));
+        assertEquals("111", OnesComplement.onesComplement("000"));
+        assertEquals("11", OnesComplement.onesComplement("00"));
+        assertEquals("1", OnesComplement.onesComplement("0"));
+    }
+
+    @Test
+    public void testOnesComplementAllOnes() {
+        // Test cases with all-one binary strings
+        assertEquals("0000", OnesComplement.onesComplement("1111"));
+        assertEquals("000", OnesComplement.onesComplement("111"));
+        assertEquals("00", OnesComplement.onesComplement("11"));
+        assertEquals("0", OnesComplement.onesComplement("1"));
+    }
+
+    @Test
+    public void testOnesComplementMixedBits() {
+        // Test more mixed binary patterns
+        assertEquals("1010", OnesComplement.onesComplement("0101"));
+        assertEquals("0101", OnesComplement.onesComplement("1010"));
+        assertEquals("1100", OnesComplement.onesComplement("0011"));
+        assertEquals("0011", OnesComplement.onesComplement("1100"));
+        assertEquals("1001", OnesComplement.onesComplement("0110"));
+    }
+
+    @Test
+    public void testOnesComplementEmptyString() {
+        // Test empty string scenario
+        assertEquals("", OnesComplement.onesComplement(""));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java b/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java
new file mode 100644
index 000000000000..512e94b6374e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test case for Highest Set Bit
+ * @author Abhinay Verma(https://github.com/Monk-AbhinayVerma)
+ */
+public class TwosComplementTest {
+
+    @Test
+    public void testTwosComplementAllZeroes() {
+        // Test with a binary number consisting entirely of zeroes
+        assertEquals("10000", TwosComplement.twosComplement("0000"));
+        assertEquals("1000", TwosComplement.twosComplement("000"));
+        assertEquals("100", TwosComplement.twosComplement("00"));
+        assertEquals("10", TwosComplement.twosComplement("0"));
+    }
+
+    @Test
+    public void testTwosComplementAllOnes() {
+        // Test with a binary number consisting entirely of ones
+        assertEquals("00001", TwosComplement.twosComplement("11111"));
+        assertEquals("0001", TwosComplement.twosComplement("1111"));
+        assertEquals("001", TwosComplement.twosComplement("111"));
+        assertEquals("01", TwosComplement.twosComplement("11"));
+    }
+
+    @Test
+    public void testTwosComplementMixedBits() {
+        // Test with binary numbers with mixed bits
+        assertEquals("1111", TwosComplement.twosComplement("0001")); // 1's complement: 1110, then add 1: 1111
+        assertEquals("1001", TwosComplement.twosComplement("0111")); // 1's complement: 1000
+        assertEquals("11001", TwosComplement.twosComplement("00111")); // 1's complement: 11000, add 1: 11001
+        assertEquals("011", TwosComplement.twosComplement("101")); // 1's complement: 010, add 1: 011
+    }
+
+    @Test
+    public void testTwosComplementSingleBit() {
+        // Test with single bit
+        assertEquals("10", TwosComplement.twosComplement("0"));
+        assertEquals("1", TwosComplement.twosComplement("1"));
+    }
+
+    @Test
+    public void testTwosComplementWithLeadingZeroes() {
+        // Test with leading zeroes in the input
+        assertEquals("1111", TwosComplement.twosComplement("0001"));
+        assertEquals("101", TwosComplement.twosComplement("011"));
+        assertEquals("110", TwosComplement.twosComplement("010"));
+    }
+}

From 48c65e4c5e9d5644762b6797f2ab902445f3da54 Mon Sep 17 00:00:00 2001
From: xuyang471 <2621860014@qq.com>
Date: Thu, 10 Oct 2024 03:50:30 +0800
Subject: [PATCH 0479/1338] Add boundary traversal of binary tree (#5639)

---
 .../trees/BoundaryTraversal.java              | 168 ++++++++++++++++++
 .../trees/BoundaryTraversalTest.java          | 108 +++++++++++
 2 files changed, 276 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/trees/BoundaryTraversal.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/BoundaryTraversalTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/BoundaryTraversal.java b/src/main/java/com/thealgorithms/datastructures/trees/BoundaryTraversal.java
new file mode 100644
index 000000000000..9a79902cc598
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/trees/BoundaryTraversal.java
@@ -0,0 +1,168 @@
+package com.thealgorithms.datastructures.trees;
+
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * BoundaryTraversal
+ * <p>
+ * Start with the Root:
+ * Add the root node to the boundary list.
+ * Traverse the Left Boundary (Excluding Leaf Nodes):
+ * Move down the left side of the tree, adding each non-leaf node to the boundary list.
+ * If a node has a left child, go left; otherwise, go right.
+ * Visit All Leaf Nodes:
+ * Traverse the tree and add all leaf nodes to the boundary list, from left to right.
+ * Traverse the Right Boundary (Excluding Leaf Nodes) in Reverse Order:
+ * Move up the right side of the tree, adding each non-leaf node to a temporary list.
+ * If a node has a right child, go right; otherwise, go left.
+ * Reverse the temporary list and add it to the boundary list.
+ * Combine and Output:
+ * The final boundary list contains the root, left boundary, leaf nodes, and reversed right boundary in that order.
+ */
+public final class BoundaryTraversal {
+    private BoundaryTraversal() {
+    }
+
+    // Main function for boundary traversal, returns a list of boundary nodes in order
+    public static List<Integer> boundaryTraversal(BinaryTree.Node root) {
+        List<Integer> result = new ArrayList<>();
+        if (root == null) {
+            return result;
+        }
+
+        // Add root node if it's not a leaf node
+        if (!isLeaf(root)) {
+            result.add(root.data);
+        }
+
+        // Add left boundary
+        addLeftBoundary(root, result);
+
+        // Add leaf nodes
+        addLeaves(root, result);
+
+        // Add right boundary
+        addRightBoundary(root, result);
+
+        return result;
+    }
+
+    // Adds the left boundary, including nodes that have no left child but have a right child
+    private static void addLeftBoundary(BinaryTree.Node node, List<Integer> result) {
+        BinaryTree.Node cur = node.left;
+
+        // If there is no left child but there is a right child, treat the right child as part of the left boundary
+        if (cur == null && node.right != null) {
+            cur = node.right;
+        }
+
+        while (cur != null) {
+            if (!isLeaf(cur)) {
+                result.add(cur.data); // Add non-leaf nodes to result
+            }
+            if (cur.left != null) {
+                cur = cur.left; // Move to the left child
+            } else if (cur.right != null) {
+                cur = cur.right; // If left child is null, move to the right child
+            } else {
+                break; // Stop if there are no children
+            }
+        }
+    }
+
+    // Adds leaf nodes (nodes without children)
+    private static void addLeaves(BinaryTree.Node node, List<Integer> result) {
+        if (node == null) {
+            return;
+        }
+        if (isLeaf(node)) {
+            result.add(node.data); // Add leaf node
+        } else {
+            addLeaves(node.left, result); // Recur for left subtree
+            addLeaves(node.right, result); // Recur for right subtree
+        }
+    }
+
+    // Adds the right boundary, excluding leaf nodes
+    private static void addRightBoundary(BinaryTree.Node node, List<Integer> result) {
+        BinaryTree.Node cur = node.right;
+        List<Integer> temp = new ArrayList<>();
+
+        // If no right boundary is present and there is no left subtree, skip
+        if (cur != null && node.left == null) {
+            return;
+        }
+        while (cur != null) {
+            if (!isLeaf(cur)) {
+                temp.add(cur.data); // Store non-leaf nodes temporarily
+            }
+            if (cur.right != null) {
+                cur = cur.right; // Move to the right child
+            } else if (cur.left != null) {
+                cur = cur.left; // If right child is null, move to the left child
+            } else {
+                break; // Stop if there are no children
+            }
+        }
+
+        // Add the right boundary nodes in reverse order
+        for (int i = temp.size() - 1; i >= 0; i--) {
+            result.add(temp.get(i));
+        }
+    }
+
+    // Checks if a node is a leaf node
+    private static boolean isLeaf(BinaryTree.Node node) {
+        return node.left == null && node.right == null;
+    }
+
+    // Iterative boundary traversal
+    public static List<Integer> iterativeBoundaryTraversal(BinaryTree.Node root) {
+        List<Integer> result = new ArrayList<>();
+        if (root == null) {
+            return result;
+        }
+
+        // Add root node if it's not a leaf node
+        if (!isLeaf(root)) {
+            result.add(root.data);
+        }
+
+        // Handle the left boundary
+        BinaryTree.Node cur = root.left;
+        if (cur == null && root.right != null) {
+            cur = root.right;
+        }
+        while (cur != null) {
+            if (!isLeaf(cur)) {
+                result.add(cur.data); // Add non-leaf nodes to result
+            }
+            cur = (cur.left != null) ? cur.left : cur.right; // Prioritize left child, move to right if left is null
+        }
+
+        // Add leaf nodes
+        addLeaves(root, result);
+
+        // Handle the right boundary using a stack (reverse order)
+        cur = root.right;
+        Deque<Integer> stack = new LinkedList<>();
+        if (cur != null && root.left == null) {
+            return result;
+        }
+        while (cur != null) {
+            if (!isLeaf(cur)) {
+                stack.push(cur.data); // Temporarily store right boundary nodes in a stack
+            }
+            cur = (cur.right != null) ? cur.right : cur.left; // Prioritize right child, move to left if right is null
+        }
+
+        // Add the right boundary nodes from the stack to maintain the correct order
+        while (!stack.isEmpty()) {
+            result.add(stack.pop());
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/BoundaryTraversalTest.java b/src/test/java/com/thealgorithms/datastructures/trees/BoundaryTraversalTest.java
new file mode 100644
index 000000000000..515dac88ce09
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/BoundaryTraversalTest.java
@@ -0,0 +1,108 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Collections;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+/**
+ *
+ */
+public class BoundaryTraversalTest {
+
+    @Test
+    public void testNullRoot() {
+        assertEquals(Collections.emptyList(), BoundaryTraversal.boundaryTraversal(null));
+        assertEquals(Collections.emptyList(), BoundaryTraversal.iterativeBoundaryTraversal(null));
+    }
+
+    @Test
+    public void testSingleNodeTree() {
+        final BinaryTree.Node root = new BinaryTree.Node(1);
+
+        List<Integer> expected = List.of(1);
+
+        assertEquals(expected, BoundaryTraversal.boundaryTraversal(root));
+        assertEquals(expected, BoundaryTraversal.iterativeBoundaryTraversal(root));
+    }
+
+    /*
+        1
+       / \
+      2   3
+     / \ / \
+    4  5 6  7
+
+    */
+    @Test
+    public void testCompleteBinaryTree() {
+        final BinaryTree.Node root = TreeTestUtils.createTree(new Integer[] {1, 2, 3, 4, 5, 6, 7});
+
+        List<Integer> expected = List.of(1, 2, 4, 5, 6, 7, 3);
+
+        assertEquals(expected, BoundaryTraversal.boundaryTraversal(root));
+        assertEquals(expected, BoundaryTraversal.iterativeBoundaryTraversal(root));
+    }
+
+    /*
+        1
+       / \
+      2   7
+     /     \
+    3       8
+     \     /
+      4   9
+         / \
+        5   6
+           / \
+         10  11
+    */
+    @Test
+    public void testBoundaryTraversal() {
+        final BinaryTree.Node root = TreeTestUtils.createTree(new Integer[] {1, 2, 7, 3, null, null, 8, null, 4, 9, null, 5, 6, 10, 11});
+
+        List<Integer> expected = List.of(1, 2, 3, 4, 5, 6, 10, 11, 9, 8, 7);
+
+        assertEquals(expected, BoundaryTraversal.boundaryTraversal(root));
+        assertEquals(expected, BoundaryTraversal.iterativeBoundaryTraversal(root));
+    }
+
+    /*
+          1
+         /
+        2
+       /
+      3
+     /
+    4
+    */
+    @Test
+    public void testLeftSkewedTree() {
+        final BinaryTree.Node root = TreeTestUtils.createTree(new Integer[] {1, 2, null, 3, null, 4, null});
+
+        List<Integer> expected = List.of(1, 2, 3, 4);
+
+        assertEquals(expected, BoundaryTraversal.boundaryTraversal(root));
+        assertEquals(expected, BoundaryTraversal.iterativeBoundaryTraversal(root));
+    }
+
+    /*
+              5
+               \
+                6
+                 \
+                  7
+                   \
+                    8
+    */
+    @Test
+    public void testRightSkewedTree() {
+        final BinaryTree.Node root = TreeTestUtils.createTree(new Integer[] {5, null, 6, null, 7, null, 8});
+
+        List<Integer> expected = List.of(5, 6, 7, 8);
+
+        assertEquals(expected, BoundaryTraversal.boundaryTraversal(root));
+        assertEquals(expected, BoundaryTraversal.iterativeBoundaryTraversal(root));
+    }
+}

From c0f35242a1d3055c345a4164ada5b4fe406f876e Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 10 Oct 2024 01:26:51 +0530
Subject: [PATCH 0480/1338] Add tests, remove `print` & `main` methods in
 `BoundaryFill.java` (#5640)

---
 DIRECTORY.md                                  |  7 ++
 .../dynamicprogramming/BoundaryFill.java      | 44 -------------
 .../dynamicprogramming/BoundaryFillTest.java  | 66 +++++++++++++++++++
 3 files changed, 73 insertions(+), 44 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 2b595e7a6652..a1a53cb2926c 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -33,8 +33,10 @@
             * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
             * [NumberAppearingOddTimes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
+            * [OnesComplement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java)
             * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
             * [SingleBitOperations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java)
+            * [TwosComplement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java)
           * ciphers
             * a5
               * [A5Cipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/A5Cipher.java)
@@ -185,6 +187,7 @@
               * [AVLSimple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java)
               * [AVLTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java)
               * [BinaryTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java)
+              * [BoundaryTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BoundaryTraversal.java)
               * [BSTFromSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTFromSortedArray.java)
               * [BSTIterative](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTIterative.java)
               * [BSTRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursive.java)
@@ -643,8 +646,10 @@
             * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
             * [NumberAppearingOddTimesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
+            * [OnesComplementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java)
             * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
             * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
+            * [TwosComplementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java)
           * ciphers
             * a5
               * [A5CipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java)
@@ -754,6 +759,7 @@
               * [StackArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java)
             * trees
               * [BinaryTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java)
+              * [BoundaryTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BoundaryTraversalTest.java)
               * [BSTFromSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTFromSortedArrayTest.java)
               * [BSTIterativeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTIterativeTest.java)
               * [BSTRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveTest.java)
@@ -783,6 +789,7 @@
             * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
           * dynamicprogramming
             * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
+            * [BoundaryFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java)
             * [BruteForceKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java)
             * [CatalanNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java)
             * [ClimbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java b/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
index 3fa8728930cb..8494492f293f 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
@@ -52,48 +52,4 @@ public static void boundaryFill(int[][] image, int xCoordinate, int yCoordinate,
             boundaryFill(image, xCoordinate - 1, yCoordinate - 1, newColor, boundaryColor);
         }
     }
-
-    /**
-     * This method will print the 2D image matrix
-     *
-     * @param image The image to be printed on the console
-     */
-    public static void printImageArray(int[][] image) {
-        for (int i = 0; i < image.length; i++) {
-            for (int j = 0; j < image[0].length; j++) {
-                System.out.print(image[i][j] + "  ");
-            }
-
-            System.out.println();
-        }
-    }
-
-    // Driver Program
-    public static void main(String[] args) {
-        // Input 2D image matrix
-        int[][] image = {
-            {0, 0, 0, 0, 0, 0, 0},
-            {0, 3, 3, 3, 3, 0, 0},
-            {0, 3, 0, 0, 3, 0, 0},
-            {0, 3, 0, 0, 3, 3, 3},
-            {0, 3, 3, 3, 0, 0, 3},
-            {0, 0, 0, 3, 0, 0, 3},
-            {0, 0, 0, 3, 3, 3, 3},
-        };
-
-        boundaryFill(image, 2, 2, 5, 3);
-
-        /* Output ==>
-                 * 0  0  0  0  0  0  0
-                   0  3  3  3  3  0  0
-                   0  3  5  5  3  0  0
-           0  3  5  5  3  3  3
-           0  3  3  3  5  5  3
-           0  0  0  3  5  5  3
-           0  0  0  3  3  3  3
-                 * */
-
-        // print 2D image matrix
-        printImageArray(image);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java
new file mode 100644
index 000000000000..4aa412731a10
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java
@@ -0,0 +1,66 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class BoundaryFillTest {
+
+    private int[][] image;
+
+    @BeforeEach
+    void setUp() {
+        image = new int[][] {{0, 0, 0, 0, 0, 0, 0}, {0, 3, 3, 3, 3, 0, 0}, {0, 3, 0, 0, 3, 0, 0}, {0, 3, 0, 0, 3, 3, 3}, {0, 3, 3, 3, 0, 0, 3}, {0, 0, 0, 3, 0, 0, 3}, {0, 0, 0, 3, 3, 3, 3}};
+    }
+
+    @Test
+    void testGetPixel() {
+        assertEquals(3, BoundaryFill.getPixel(image, 1, 1));
+        assertEquals(0, BoundaryFill.getPixel(image, 2, 2));
+        assertEquals(3, BoundaryFill.getPixel(image, 4, 3));
+    }
+
+    @Test
+    void testPutPixel() {
+        BoundaryFill.putPixel(image, 2, 2, 5);
+        assertEquals(5, BoundaryFill.getPixel(image, 2, 2));
+
+        BoundaryFill.putPixel(image, 0, 0, 7);
+        assertEquals(7, BoundaryFill.getPixel(image, 0, 0));
+    }
+
+    @Test
+    void testBoundaryFill() {
+        BoundaryFill.boundaryFill(image, 2, 2, 5, 3);
+
+        int[][] expectedImage = {{0, 0, 0, 0, 0, 0, 0}, {0, 3, 3, 3, 3, 0, 0}, {0, 3, 5, 5, 3, 0, 0}, {0, 3, 5, 5, 3, 3, 3}, {0, 3, 3, 3, 5, 5, 3}, {0, 0, 0, 3, 5, 5, 3}, {0, 0, 0, 3, 3, 3, 3}};
+
+        for (int i = 0; i < image.length; i++) {
+            assertArrayEquals(expectedImage[i], image[i]);
+        }
+    }
+
+    @Test
+    void testBoundaryFillEdgeCase() {
+        BoundaryFill.boundaryFill(image, 1, 1, 3, 3);
+
+        int[][] expectedImage = {{0, 0, 0, 0, 0, 0, 0}, {0, 3, 3, 3, 3, 0, 0}, {0, 3, 0, 0, 3, 0, 0}, {0, 3, 0, 0, 3, 3, 3}, {0, 3, 3, 3, 0, 0, 3}, {0, 0, 0, 3, 0, 0, 3}, {0, 0, 0, 3, 3, 3, 3}};
+
+        for (int i = 0; i < image.length; i++) {
+            assertArrayEquals(expectedImage[i], image[i]);
+        }
+    }
+
+    @Test
+    void testBoundaryFillInvalidCoordinates() {
+        BoundaryFill.boundaryFill(image, -1, -1, 5, 3);
+
+        int[][] expectedImage = {{0, 0, 0, 0, 0, 0, 0}, {0, 3, 3, 3, 3, 0, 0}, {0, 3, 0, 0, 3, 0, 0}, {0, 3, 0, 0, 3, 3, 3}, {0, 3, 3, 3, 0, 0, 3}, {0, 0, 0, 3, 0, 0, 3}, {0, 0, 0, 3, 3, 3, 3}};
+
+        for (int i = 0; i < image.length; i++) {
+            assertArrayEquals(expectedImage[i], image[i]);
+        }
+    }
+}

From 6535d4755d8bed3cd410571568d0200f01bd806a Mon Sep 17 00:00:00 2001
From: Lakshyajeet Singh Goyal
 <74810454+DarkMatter-999@users.noreply.github.com>
Date: Thu, 10 Oct 2024 01:32:41 +0530
Subject: [PATCH 0481/1338] Add SwapAdjacentBits algorithm (#5634)

---
 .../bitmanipulation/SwapAdjacentBits.java     | 26 +++++++++++++++++++
 .../bitmanipulation/SwapAdjacentBitsTest.java | 22 ++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java b/src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java
new file mode 100644
index 000000000000..933dec5654a0
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java
@@ -0,0 +1,26 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * Swap every pair of adjacent bits of a given number.
+ * @author Lakshyajeet Singh Goyal (https://github.com/DarkMatter-999)
+ */
+
+public final class SwapAdjacentBits {
+    private SwapAdjacentBits() {
+    }
+
+    public static int swapAdjacentBits(int num) {
+        // mask the even bits (0xAAAAAAAA => 10101010...)
+        int evenBits = num & 0xAAAAAAAA;
+
+        // mask the odd bits (0x55555555 => 01010101...)
+        int oddBits = num & 0x55555555;
+
+        // right shift even bits and left shift odd bits
+        evenBits >>= 1;
+        oddBits <<= 1;
+
+        // combine shifted bits
+        return evenBits | oddBits;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java
new file mode 100644
index 000000000000..67c986136ab0
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class SwapAdjacentBitsTest {
+
+    @ParameterizedTest
+    @CsvSource({
+        "2, 1", // 2 (10 in binary) should become 1 (01 in binary)
+        "43, 23", // 43 should become 23
+        "153, 102", // 153 should become 102
+        "15, 15", // 15 (1111) remains 15 (1111)
+        "0, 0" // 0 (0000) remains 0 (0000)
+    })
+    void
+    testSwapAdjacentBits(int input, int expected) {
+        assertEquals(expected, SwapAdjacentBits.swapAdjacentBits(input));
+    }
+}

From d4fff30eaa1d3a4f5ef292c72a3c9bd1591966ef Mon Sep 17 00:00:00 2001
From: Tuhinm2002 <75078694+Tuhinm2002@users.noreply.github.com>
Date: Thu, 10 Oct 2024 13:02:02 +0530
Subject: [PATCH 0482/1338] feat : new bit manipulation algo `Single element in
 an array` (#5689)

* feat : new algo uniquesubseqcount

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* feat : new bitmanipulation algo

---------

Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 .../bitmanipulation/SingleElement.java        | 39 +++++++++++++++++++
 .../bitmanipulation/SingleElementTest.java    | 33 ++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/SingleElement.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/SingleElementTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/SingleElement.java b/src/main/java/com/thealgorithms/bitmanipulation/SingleElement.java
new file mode 100644
index 000000000000..85ebdf02db25
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/SingleElement.java
@@ -0,0 +1,39 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * Utility class to find the single non-duplicate element from an array
+ * where all other elements appear twice.
+ * <p>
+ * The algorithm runs in O(n) time complexity and O(1) space complexity
+ * using bitwise XOR.
+ * </p>
+ *
+ * @author <a href="http://github.com/tuhinm2002">Tuhin M</a>
+ */
+public final class SingleElement {
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     * Throws an UnsupportedOperationException if attempted.
+     */
+    private SingleElement() {
+        throw new UnsupportedOperationException("Utility Class");
+    }
+
+    /**
+     * Finds the single non-duplicate element in an array where every other
+     * element appears exactly twice. Uses bitwise XOR to achieve O(n) time
+     * complexity and O(1) space complexity.
+     *
+     * @param arr the input array containing integers where every element
+     *            except one appears exactly twice
+     * @return the single non-duplicate element
+     */
+    public static int findSingleElement(int[] arr) {
+        int ele = 0;
+        for (int i = 0; i < arr.length; i++) {
+            ele ^= arr[i];
+        }
+        return ele;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/SingleElementTest.java b/src/test/java/com/thealgorithms/bitmanipulation/SingleElementTest.java
new file mode 100644
index 000000000000..2e2afe99b0da
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/SingleElementTest.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public final class SingleElementTest {
+
+    /**
+     * Parameterized test to find the single non-duplicate element
+     * in the given arrays.
+     *
+     * @param arr  the input array where every element appears twice except one
+     * @param expected the expected single element result
+     */
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testFindSingleElement(int[] arr, int expected) {
+        assertEquals(expected, SingleElement.findSingleElement(arr));
+    }
+
+    /**
+     * Provides test cases for the parameterized test.
+     *
+     * @return Stream of arguments consisting of arrays and expected results
+     */
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new int[] {1, 1, 2, 2, 4, 4, 3}, 3), Arguments.of(new int[] {1, 2, 2, 3, 3}, 1), Arguments.of(new int[] {10}, 10));
+    }
+}

From 90d20b3a43642548ecc55e425517583080a81e2a Mon Sep 17 00:00:00 2001
From: Prayas Kumar <71717433+prayas7102@users.noreply.github.com>
Date: Thu, 10 Oct 2024 13:09:22 +0530
Subject: [PATCH 0483/1338] Add smoothing constant to IDF formula in BM25 to
 prevent negative scores (#5696)

Co-authored-by: prayas7102 <prayas.prithvirajpratap7@example.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 .../thealgorithms/searches/BM25InvertedIndex.java    |  2 +-
 .../searches/BM25InvertedIndexTest.java              | 12 +++++++-----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java b/src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java
index 1cfd2bbad8e4..aeddc591b32b 100644
--- a/src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java
+++ b/src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java
@@ -215,6 +215,6 @@ private double computeBM25Score(int termFrequency, double docLength, double idf)
      */
     private double computeIDF(int docFrequency) {
         // Total number of documents in the index
-        return Math.log((totalDocuments - docFrequency + 0.5) / (docFrequency + 0.5));
+        return Math.log((totalDocuments - docFrequency + 0.5) / (docFrequency + 0.5) + 1);
     }
 }
diff --git a/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java b/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java
index 8595e0a00683..2017c11dfb3c 100644
--- a/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java
+++ b/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java
@@ -50,13 +50,15 @@ void testSearchRanking() {
         // Perform search for the term "good"
         List<SearchResult> results = index.search("good");
         assertFalse(results.isEmpty());
-
+        for (SearchResult result : results) {
+            System.out.println(result);
+        }
         // Validate the ranking based on the provided relevance scores
-        assertEquals(6, results.get(0).getDocId()); // It's a Wonderful Life should be ranked 1st
-        assertEquals(7, results.get(1).getDocId()); // The Pursuit of Happyness should be ranked 2nd
+        assertEquals(1, results.get(0).getDocId()); // The Shawshank Redemption should be ranked 1st
+        assertEquals(8, results.get(1).getDocId()); // A Few Good Men should be ranked 2nd
         assertEquals(5, results.get(2).getDocId()); // Good Will Hunting should be ranked 3rd
-        assertEquals(8, results.get(3).getDocId()); // A Few Good Men should be ranked 4th
-        assertEquals(1, results.get(4).getDocId()); // The Shawshank Redemption should be ranked 5th
+        assertEquals(7, results.get(3).getDocId()); // The Pursuit of Happyness should be ranked 4th
+        assertEquals(6, results.get(4).getDocId()); // It's a Wonderful Life should be ranked 5th
 
         // Ensure the relevance scores are in descending order
         for (int i = 0; i < results.size() - 1; i++) {

From bd3b754eda50b4634c7496b1355bbe57b2964bea Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 10 Oct 2024 22:26:44 +0530
Subject: [PATCH 0484/1338] Add EDFScheduling algorithm (#5657)

---
 DIRECTORY.md                                  |  6 ++
 .../scheduling/EDFScheduling.java             | 99 +++++++++++++++++++
 .../scheduling/EDFSchedulingTest.java         | 69 +++++++++++++
 3 files changed, 174 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/EDFScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a1a53cb2926c..46affca47109 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -36,6 +36,8 @@
             * [OnesComplement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java)
             * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
             * [SingleBitOperations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java)
+            * [SingleElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleElement.java)
+            * [SwapAdjacentBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java)
             * [TwosComplement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java)
           * ciphers
             * a5
@@ -476,6 +478,7 @@
           * Recursion
             * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java)
           * scheduling
+            * [EDFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/EDFScheduling.java)
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
             * [HighestResponseRatioNextScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
             * [JobSchedulingWithDeadline](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java)
@@ -649,6 +652,8 @@
             * [OnesComplementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java)
             * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
             * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
+            * [SingleElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleElementTest.java)
+            * [SwapAdjacentBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java)
             * [TwosComplementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java)
           * ciphers
             * a5
@@ -975,6 +980,7 @@
           * Recursion
             * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java)
           * scheduling
+            * [EDFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java)
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
             * [HighestResponseRatioNextSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
             * [JobSchedulingWithDeadlineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/EDFScheduling.java b/src/main/java/com/thealgorithms/scheduling/EDFScheduling.java
new file mode 100644
index 000000000000..5ba79cdbb73a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/EDFScheduling.java
@@ -0,0 +1,99 @@
+package com.thealgorithms.scheduling;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * The Earliest Deadline First (EDF) Scheduling class implements a dynamic scheduling algorithm.
+ * It assigns the CPU to processes with the earliest deadlines, ensuring that deadlines are met if possible.
+ * This scheduling algorithm is ideal for real-time systems where meeting deadlines is critical.
+ */
+public final class EDFScheduling {
+    private EDFScheduling() {
+    }
+
+    private List<Process> processes;
+
+    /**
+     * Constructs an EDFScheduling object with a list of processes.
+     *
+     * @param processes List of processes to be scheduled.
+     */
+    public EDFScheduling(final List<Process> processes) {
+        this.processes = processes;
+    }
+
+    /**
+     * Schedules the processes using Earliest Deadline First (EDF) scheduling.
+     * Processes are sorted by their deadlines, and the method simulates their execution.
+     * It calculates the waiting time and turnaround time for each process.
+     *
+     * @return List of processes after they have been executed in order of earliest deadline first.
+     */
+    public List<Process> scheduleProcesses() {
+        processes.sort(Comparator.comparingInt(Process::getDeadline));
+
+        int currentTime = 0;
+        List<Process> executedProcesses = new ArrayList<>();
+
+        for (Process process : processes) {
+            process.setWaitingTime(currentTime);
+            currentTime += process.getBurstTime();
+            process.setTurnAroundTime(process.getWaitingTime() + process.getBurstTime());
+
+            if (currentTime > process.getDeadline()) {
+                System.out.println("Warning: Process " + process.getProcessId() + " missed its deadline.");
+            }
+
+            executedProcesses.add(process);
+        }
+
+        return executedProcesses;
+    }
+
+    /**
+     * The Process class represents a process with an ID, burst time, deadline, waiting time, and turnaround time.
+     */
+    public static class Process {
+        private String processId;
+        private int burstTime;
+        private int deadline;
+        private int waitingTime;
+        private int turnAroundTime;
+
+        public Process(String processId, int burstTime, int deadline) {
+            this.processId = processId;
+            this.burstTime = burstTime;
+            this.deadline = deadline;
+        }
+
+        public String getProcessId() {
+            return processId;
+        }
+
+        public int getBurstTime() {
+            return burstTime;
+        }
+
+        public int getDeadline() {
+            return deadline;
+        }
+
+        public int getWaitingTime() {
+            return waitingTime;
+        }
+
+        public void setWaitingTime(int waitingTime) {
+            this.waitingTime = waitingTime;
+        }
+
+        public int getTurnAroundTime() {
+            return turnAroundTime;
+        }
+
+        public void setTurnAroundTime(int turnAroundTime) {
+            this.turnAroundTime = turnAroundTime;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java
new file mode 100644
index 000000000000..8ce290cb246f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class EDFSchedulingTest {
+
+    private List<EDFScheduling.Process> processes;
+
+    @BeforeEach
+    public void setup() {
+        processes = createProcesses();
+    }
+
+    @Test
+    public void testEDFScheduling() {
+        EDFScheduling edfScheduling = new EDFScheduling(processes);
+        List<EDFScheduling.Process> executedProcesses = edfScheduling.scheduleProcesses();
+
+        // Assert the correct number of processes
+        assertEquals(3, executedProcesses.size());
+
+        // Assert that processes are executed in order of earliest deadline first
+        EDFScheduling.Process process1 = executedProcesses.get(0);
+        assertEquals("P2", process1.getProcessId());
+        assertEquals(0, process1.getWaitingTime());
+        assertEquals(3, process1.getTurnAroundTime());
+
+        EDFScheduling.Process process2 = executedProcesses.get(1);
+        assertEquals("P1", process2.getProcessId());
+        assertEquals(3, process2.getWaitingTime());
+        assertEquals(10, process2.getTurnAroundTime());
+
+        EDFScheduling.Process process3 = executedProcesses.get(2);
+        assertEquals("P3", process3.getProcessId());
+        assertEquals(10, process3.getWaitingTime());
+        assertEquals(18, process3.getTurnAroundTime());
+    }
+
+    @Test
+    public void testProcessMissedDeadline() {
+        // Modify the deadline of a process to ensure it will miss its deadline
+        processes.get(1).setTurnAroundTime(5); // Set P1's deadline to 5 (which it will miss)
+
+        EDFScheduling edfScheduling = new EDFScheduling(processes);
+        edfScheduling.scheduleProcesses();
+
+        // Check if the process with ID "P1" missed its deadline
+        assertEquals("P1", processes.get(1).getProcessId());
+    }
+
+    private List<EDFScheduling.Process> createProcesses() {
+        // Process ID, Burst Time, Deadline
+        EDFScheduling.Process process1 = new EDFScheduling.Process("P1", 7, 10); // 7 burst time, 10 deadline
+        EDFScheduling.Process process2 = new EDFScheduling.Process("P2", 3, 5); // 3 burst time, 5 deadline
+        EDFScheduling.Process process3 = new EDFScheduling.Process("P3", 8, 18); // 8 burst time, 18 deadline
+
+        List<EDFScheduling.Process> processes = new ArrayList<>();
+        processes.add(process1);
+        processes.add(process2);
+        processes.add(process3);
+
+        return processes;
+    }
+}

From e728aa7d6fc113fddb5cfff3fab337954978229a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 10 Oct 2024 22:46:04 +0530
Subject: [PATCH 0485/1338] Add tests, remove `main`, enhance docs in
 `MatrixChainMultiplication` (#5658)

---
 DIRECTORY.md                                  |   1 +
 .../MatrixChainMultiplication.java            | 194 ++++++++++--------
 .../MatrixChainMultiplicationTest.java        |  54 +++++
 3 files changed, 163 insertions(+), 86 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplicationTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 46affca47109..1407ba199756 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -814,6 +814,7 @@
             * [LongestIncreasingSubsequenceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java)
             * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java)
             * [LongestValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java)
+            * [MatrixChainMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplicationTest.java)
             * [MinimumPathSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java)
             * [MinimumSumPartitionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java)
             * [OptimalJobSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
index 45568d21f295..1edb7207dee2 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java
@@ -2,38 +2,32 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Scanner;
 
+/**
+ * The MatrixChainMultiplication class provides functionality to compute the
+ * optimal way to multiply a sequence of matrices. The optimal multiplication
+ * order is determined using dynamic programming, which minimizes the total
+ * number of scalar multiplications required.
+ */
 public final class MatrixChainMultiplication {
     private MatrixChainMultiplication() {
     }
 
-    private static final Scanner SCANNER = new Scanner(System.in);
-    private static final ArrayList<Matrix> MATRICES = new ArrayList<>();
-    private static int size;
+    // Matrices to store minimum multiplication costs and split points
     private static int[][] m;
     private static int[][] s;
     private static int[] p;
 
-    public static void main(String[] args) {
-        int count = 1;
-        while (true) {
-            String[] mSize = input("input size of matrix A(" + count + ") ( ex. 10 20 ) : ");
-            int col = Integer.parseInt(mSize[0]);
-            if (col == 0) {
-                break;
-            }
-            int row = Integer.parseInt(mSize[1]);
-
-            Matrix matrix = new Matrix(count, col, row);
-            MATRICES.add(matrix);
-            count++;
-        }
-        for (Matrix m : MATRICES) {
-            System.out.format("A(%d)  =  %2d  x  %2d%n", m.count(), m.col(), m.row());
-        }
-
-        size = MATRICES.size();
+    /**
+     * Calculates the optimal order for multiplying a given list of matrices.
+     *
+     * @param matrices an ArrayList of Matrix objects representing the matrices
+     *                 to be multiplied.
+     * @return a Result object containing the matrices of minimum costs and
+     *         optimal splits.
+     */
+    public static Result calculateMatrixChainOrder(ArrayList<Matrix> matrices) {
+        int size = matrices.size();
         m = new int[size + 1][size + 1];
         s = new int[size + 1][size + 1];
         p = new int[size + 1];
@@ -44,51 +38,20 @@ public static void main(String[] args) {
         }
 
         for (int i = 0; i < p.length; i++) {
-            p[i] = i == 0 ? MATRICES.get(i).col() : MATRICES.get(i - 1).row();
+            p[i] = i == 0 ? matrices.get(i).col() : matrices.get(i - 1).row();
         }
 
-        matrixChainOrder();
-        for (int i = 0; i < size; i++) {
-            System.out.print("-------");
-        }
-        System.out.println();
-        printArray(m);
-        for (int i = 0; i < size; i++) {
-            System.out.print("-------");
-        }
-        System.out.println();
-        printArray(s);
-        for (int i = 0; i < size; i++) {
-            System.out.print("-------");
-        }
-        System.out.println();
-
-        System.out.println("Optimal solution : " + m[1][size]);
-        System.out.print("Optimal parens : ");
-        printOptimalParens(1, size);
-    }
-
-    private static void printOptimalParens(int i, int j) {
-        if (i == j) {
-            System.out.print("A" + i);
-        } else {
-            System.out.print("(");
-            printOptimalParens(i, s[i][j]);
-            printOptimalParens(s[i][j] + 1, j);
-            System.out.print(")");
-        }
-    }
-
-    private static void printArray(int[][] array) {
-        for (int i = 1; i < size + 1; i++) {
-            for (int j = 1; j < size + 1; j++) {
-                System.out.printf("%7d", array[i][j]);
-            }
-            System.out.println();
-        }
+        matrixChainOrder(size);
+        return new Result(m, s);
     }
 
-    private static void matrixChainOrder() {
+    /**
+     * A helper method that computes the minimum cost of multiplying
+     * the matrices using dynamic programming.
+     *
+     * @param size the number of matrices in the multiplication sequence.
+     */
+    private static void matrixChainOrder(int size) {
         for (int i = 1; i < size + 1; i++) {
             m[i][i] = 0;
         }
@@ -109,33 +72,92 @@ private static void matrixChainOrder() {
         }
     }
 
-    private static String[] input(String string) {
-        System.out.print(string);
-        return (SCANNER.nextLine().split(" "));
-    }
-}
-
-class Matrix {
+    /**
+     * The Result class holds the results of the matrix chain multiplication
+     * calculation, including the matrix of minimum costs and split points.
+     */
+    public static class Result {
+        private final int[][] m;
+        private final int[][] s;
+
+        /**
+         * Constructs a Result object with the specified matrices of minimum
+         * costs and split points.
+         *
+         * @param m the matrix of minimum multiplication costs.
+         * @param s the matrix of optimal split points.
+         */
+        public Result(int[][] m, int[][] s) {
+            this.m = m;
+            this.s = s;
+        }
 
-    private final int count;
-    private final int col;
-    private final int row;
+        /**
+         * Returns the matrix of minimum multiplication costs.
+         *
+         * @return the matrix of minimum multiplication costs.
+         */
+        public int[][] getM() {
+            return m;
+        }
 
-    Matrix(int count, int col, int row) {
-        this.count = count;
-        this.col = col;
-        this.row = row;
+        /**
+         * Returns the matrix of optimal split points.
+         *
+         * @return the matrix of optimal split points.
+         */
+        public int[][] getS() {
+            return s;
+        }
     }
 
-    int count() {
-        return count;
-    }
+    /**
+     * The Matrix class represents a matrix with its dimensions and count.
+     */
+    public static class Matrix {
+        private final int count;
+        private final int col;
+        private final int row;
+
+        /**
+         * Constructs a Matrix object with the specified count, number of columns,
+         * and number of rows.
+         *
+         * @param count the identifier for the matrix.
+         * @param col   the number of columns in the matrix.
+         * @param row   the number of rows in the matrix.
+         */
+        public Matrix(int count, int col, int row) {
+            this.count = count;
+            this.col = col;
+            this.row = row;
+        }
 
-    int col() {
-        return col;
-    }
+        /**
+         * Returns the identifier of the matrix.
+         *
+         * @return the identifier of the matrix.
+         */
+        public int count() {
+            return count;
+        }
 
-    int row() {
-        return row;
+        /**
+         * Returns the number of columns in the matrix.
+         *
+         * @return the number of columns in the matrix.
+         */
+        public int col() {
+            return col;
+        }
+
+        /**
+         * Returns the number of rows in the matrix.
+         *
+         * @return the number of rows in the matrix.
+         */
+        public int row() {
+            return row;
+        }
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplicationTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplicationTest.java
new file mode 100644
index 000000000000..2bee0ca52918
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplicationTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import org.junit.jupiter.api.Test;
+
+class MatrixChainMultiplicationTest {
+
+    @Test
+    void testMatrixCreation() {
+        MatrixChainMultiplication.Matrix matrix1 = new MatrixChainMultiplication.Matrix(1, 10, 20);
+        MatrixChainMultiplication.Matrix matrix2 = new MatrixChainMultiplication.Matrix(2, 20, 30);
+
+        assertEquals(1, matrix1.count());
+        assertEquals(10, matrix1.col());
+        assertEquals(20, matrix1.row());
+
+        assertEquals(2, matrix2.count());
+        assertEquals(20, matrix2.col());
+        assertEquals(30, matrix2.row());
+    }
+
+    @Test
+    void testMatrixChainOrder() {
+        // Create a list of matrices to be multiplied
+        ArrayList<MatrixChainMultiplication.Matrix> matrices = new ArrayList<>();
+        matrices.add(new MatrixChainMultiplication.Matrix(1, 10, 20)); // A(1) = 10 x 20
+        matrices.add(new MatrixChainMultiplication.Matrix(2, 20, 30)); // A(2) = 20 x 30
+
+        // Calculate matrix chain order
+        MatrixChainMultiplication.Result result = MatrixChainMultiplication.calculateMatrixChainOrder(matrices);
+
+        // Expected cost of multiplying A(1) and A(2)
+        int expectedCost = 6000; // The expected optimal cost of multiplying A(1)(10x20) and A(2)(20x30)
+        int actualCost = result.getM()[1][2];
+
+        assertEquals(expectedCost, actualCost);
+    }
+
+    @Test
+    void testOptimalParentheses() {
+        // Create a list of matrices to be multiplied
+        ArrayList<MatrixChainMultiplication.Matrix> matrices = new ArrayList<>();
+        matrices.add(new MatrixChainMultiplication.Matrix(1, 10, 20)); // A(1) = 10 x 20
+        matrices.add(new MatrixChainMultiplication.Matrix(2, 20, 30)); // A(2) = 20 x 30
+
+        // Calculate matrix chain order
+        MatrixChainMultiplication.Result result = MatrixChainMultiplication.calculateMatrixChainOrder(matrices);
+
+        // Check the optimal split for parentheses
+        assertEquals(1, result.getS()[1][2]); // s[1][2] should point to the optimal split
+    }
+}

From c152c38d1b3c429db8b8054ab31cc07252fc89fa Mon Sep 17 00:00:00 2001
From: Andrii Siriak <siryaka@gmail.com>
Date: Thu, 10 Oct 2024 21:03:56 +0300
Subject: [PATCH 0486/1338] Update build.yml (#5709)

---
 .github/workflows/build.yml  | 2 +-
 .github/workflows/codeql.yml | 2 +-
 .github/workflows/infer.yml  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 14a4ce5fe0f5..8178509e7258 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -10,7 +10,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           java-version: 21
-          distribution: 'adopt'
+          distribution: 'temurin'
       - name: Build with Maven
         run: mvn --batch-mode --update-snapshots verify
       - name: Upload coverage to codecov (tokenless)
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index ff76b1af452a..a0908a2b57d9 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           java-version: 21
-          distribution: 'adopt'
+          distribution: 'temurin'
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v3
diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index 121a6c728fbb..a07c6f458083 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -18,7 +18,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           java-version: 21
-          distribution: 'adopt'
+          distribution: 'temurin'
 
       - name: Set up OCaml
         uses: ocaml/setup-ocaml@v3

From 44b0fc9408a7cf5848cb8e822ccea57a79e5dfb4 Mon Sep 17 00:00:00 2001
From: Guhapriya Dharmaraj <76595809+Guhapriya01@users.noreply.github.com>
Date: Thu, 10 Oct 2024 23:37:44 +0530
Subject: [PATCH 0487/1338]  Implement Maximum Sum of Non-Adjacent Elements
 (#5544)

---
 .../MaximumSumOfNonAdjacentElements.java      | 95 +++++++++++++++++++
 .../MaximumSumOfNonAdjacentElementsTest.java  | 52 ++++++++++
 2 files changed, 147 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElements.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElementsTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElements.java b/src/main/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElements.java
new file mode 100644
index 000000000000..49af3ae3db88
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElements.java
@@ -0,0 +1,95 @@
+package com.thealgorithms.dynamicprogramming;
+
+/**
+ * Class to find the maximum sum of non-adjacent elements in an array. This
+ * class contains two approaches: one with O(n) space complexity and another
+ * with O(1) space optimization. For more information, refer to
+ * https://takeuforward.org/data-structure/maximum-sum-of-non-adjacent-elements-dp-5/
+ */
+final class MaximumSumOfNonAdjacentElements {
+
+    private MaximumSumOfNonAdjacentElements() {
+    }
+
+    /**
+     * Approach 1: Uses a dynamic programming array to store the maximum sum at
+     * each index. Time Complexity: O(n) - where n is the length of the input
+     * array. Space Complexity: O(n) - due to the additional dp array.
+     * @param arr The input array of integers.
+     * @return The maximum sum of non-adjacent elements.
+     */
+    public static int getMaxSumApproach1(int[] arr) {
+        if (arr.length == 0) {
+            return 0; // Check for empty array
+        }
+
+        int n = arr.length;
+        int[] dp = new int[n];
+
+        // Base case: Maximum sum if only one element is present.
+        dp[0] = arr[0];
+
+        for (int ind = 1; ind < n; ind++) {
+
+            // Case 1: Do not take the current element, carry forward the previous max
+            // sum.
+            int notTake = dp[ind - 1];
+
+            // Case 2: Take the current element, add it to the max sum up to two
+            // indices before.
+            int take = arr[ind];
+            if (ind > 1) {
+                take += dp[ind - 2];
+            }
+
+            // Store the maximum of both choices in the dp array.
+            dp[ind] = Math.max(take, notTake);
+        }
+
+        return dp[n - 1];
+    }
+
+    /**
+     * Approach 2: Optimized space complexity approach using two variables instead
+     * of an array. Time Complexity: O(n) - where n is the length of the input
+     * array. Space Complexity: O(1) - as it only uses constant space for two
+     * variables.
+     * @param arr The input array of integers.
+     * @return The maximum sum of non-adjacent elements.
+     */
+    public static int getMaxSumApproach2(int[] arr) {
+        if (arr.length == 0) {
+            return 0; // Check for empty array
+        }
+
+        int n = arr.length;
+
+        // Two variables to keep track of previous two results:
+        // prev1 = max sum up to the last element (n-1)
+        // prev2 = max sum up to the element before last (n-2)
+
+        int prev1 = arr[0]; // Base case: Maximum sum for the first element.
+        int prev2 = 0;
+
+        for (int ind = 1; ind < n; ind++) {
+            // Case 1: Do not take the current element, keep the last max sum.
+            int notTake = prev1;
+
+            // Case 2: Take the current element and add it to the result from two
+            // steps back.
+            int take = arr[ind];
+            if (ind > 1) {
+                take += prev2;
+            }
+
+            // Calculate the current maximum sum and update previous values.
+            int current = Math.max(take, notTake);
+
+            // Shift prev1 and prev2 for the next iteration.
+            prev2 = prev1;
+            prev1 = current;
+        }
+
+        return prev1;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElementsTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElementsTest.java
new file mode 100644
index 000000000000..3f312d86462e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElementsTest.java
@@ -0,0 +1,52 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class MaximumSumOfNonAdjacentElementsTest {
+
+    // Tests for Approach1
+    @Test
+    public void testGetMaxSumApproach1WithEmptyArray() {
+        assertEquals(0, MaximumSumOfNonAdjacentElements.getMaxSumApproach1(new int[] {})); // Empty array
+    }
+
+    @Test
+    public void testGetMaxSumApproach1WithSingleElement() {
+        assertEquals(1, MaximumSumOfNonAdjacentElements.getMaxSumApproach1(new int[] {1})); // Single element
+    }
+
+    @Test
+    public void testGetMaxSumApproach1WithTwoElementsTakeMax() {
+        assertEquals(2, MaximumSumOfNonAdjacentElements.getMaxSumApproach1(new int[] {1, 2})); // Take max of both
+    }
+
+    @Test
+    public void testGetMaxSumApproach1WithMultipleElements() {
+        assertEquals(15, MaximumSumOfNonAdjacentElements.getMaxSumApproach1(new int[] {3, 2, 5, 10, 7})); // 3 + 7 + 5
+        assertEquals(10, MaximumSumOfNonAdjacentElements.getMaxSumApproach1(new int[] {5, 1, 1, 5})); // 5 + 5
+    }
+
+    // Tests for Approach2
+    @Test
+    public void testGetMaxSumApproach2WithEmptyArray() {
+        assertEquals(0, MaximumSumOfNonAdjacentElements.getMaxSumApproach2(new int[] {})); // Empty array
+    }
+
+    @Test
+    public void testGetMaxSumApproach2WithSingleElement() {
+        assertEquals(1, MaximumSumOfNonAdjacentElements.getMaxSumApproach2(new int[] {1})); // Single element
+    }
+
+    @Test
+    public void testGetMaxSumApproach2WithTwoElementsTakeMax() {
+        assertEquals(2, MaximumSumOfNonAdjacentElements.getMaxSumApproach2(new int[] {1, 2})); // Take max of both
+    }
+
+    @Test
+    public void testGetMaxSumApproach2WithMultipleElements() {
+        assertEquals(15, MaximumSumOfNonAdjacentElements.getMaxSumApproach2(new int[] {3, 2, 5, 10, 7})); // 3 + 7 + 5
+        assertEquals(10, MaximumSumOfNonAdjacentElements.getMaxSumApproach2(new int[] {5, 1, 1, 5})); // 5 + 5
+    }
+}

From 41f7e6aa9d0b8a60639681d5668469c705b00590 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 10 Oct 2024 23:41:43 +0530
Subject: [PATCH 0488/1338] Add tests, improve docs in `NewManShanksPrime`
 (#5660)

---
 DIRECTORY.md                                  |  3 +
 .../dynamicprogramming/NewManShanksPrime.java | 35 ++++++--
 .../NewManShanksPrimeTest.java                | 80 +++++++++++++++++++
 3 files changed, 112 insertions(+), 6 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/NewManShanksPrimeTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 1407ba199756..4afe7c78e0eb 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -262,6 +262,7 @@
             * [LongestValidParentheses](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestValidParentheses.java)
             * [MatrixChainMultiplication](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java)
             * [MatrixChainRecursiveTopDownMemoisation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java)
+            * [MaximumSumOfNonAdjacentElements](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElements.java)
             * [MinimumPathSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/MinimumPathSum.java)
             * [MinimumSumPartition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/MinimumSumPartition.java)
             * [NewManShanksPrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java)
@@ -815,8 +816,10 @@
             * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java)
             * [LongestValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java)
             * [MatrixChainMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplicationTest.java)
+            * [MaximumSumOfNonAdjacentElementsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElementsTest.java)
             * [MinimumPathSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java)
             * [MinimumSumPartitionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java)
+            * [NewManShanksPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/NewManShanksPrimeTest.java)
             * [OptimalJobSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
             * [PalindromicPartitioningTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioningTest.java)
             * [PartitionProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java b/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
index d15ea1f78a78..3db40148f1c2 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java
@@ -1,25 +1,48 @@
 package com.thealgorithms.dynamicprogramming;
 
 /**
+ * The NewManShanksPrime class provides a method to determine whether the nth
+ * New Man Shanks prime matches an expected answer.
+ *
+ * <p>This is based on the New Man Shanks prime sequence defined by the recurrence
+ * relation:</p>
+ *
+ * <pre>
+ * a(n) = 2 * a(n-1) + a(n-2) for n >= 2
+ * a(0) = 1
+ * a(1) = 1
+ * </pre>
+ *
+ * <p>For more information on New Man Shanks primes, please refer to the
+ * <a href="https://en.wikipedia.org/wiki/Newman%E2%80%93Shanks%E2%80%93Williams_prime">
+ * Wikipedia article</a>.</p>
+ *
+ * <p>Note: The class is designed to be non-instantiable.</p>
+ *
  * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
- * Program description - To find the New Man Shanks Prime.
- * <a href="https://en.wikipedia.org/wiki/Newman%E2%80%93Shanks%E2%80%93Williams_prime">Wikipedia</a>
  */
 public final class NewManShanksPrime {
     private NewManShanksPrime() {
     }
 
+    /**
+     * Calculates the nth New Man Shanks prime and checks if it equals the
+     * expected answer.
+     *
+     * @param n the index of the New Man Shanks prime to calculate (0-based).
+     * @param expectedAnswer the expected value of the nth New Man Shanks prime.
+     * @return true if the calculated nth New Man Shanks prime matches the
+     *         expected answer; false otherwise.
+     */
     public static boolean nthManShanksPrime(int n, int expectedAnswer) {
         int[] a = new int[n + 1];
-        // array of n+1 size is initialized
         a[0] = 1;
         a[1] = 1;
-        // The 0th and 1st index position values are fixed. They are initialized as 1
+
         for (int i = 2; i <= n; i++) {
             a[i] = 2 * a[i - 1] + a[i - 2];
         }
-        // The loop is continued till n
+
         return a[n] == expectedAnswer;
-        // returns true if calculated answer matches with expected answer
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/NewManShanksPrimeTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/NewManShanksPrimeTest.java
new file mode 100644
index 000000000000..a16ad67d6470
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/NewManShanksPrimeTest.java
@@ -0,0 +1,80 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the NewManShanksPrime class.
+ * This test class verifies the correctness of the nthManShanksPrime method
+ * for various input cases.
+ */
+class NewManShanksPrimeTest {
+
+    /**
+     * Test case for the 1st New Man Shanks prime.
+     * The expected answer is 1.
+     */
+    @Test
+    void testNthManShanksPrime1() {
+        int n = 1;
+        int expectedAnswer = 1;
+        assertTrue(NewManShanksPrime.nthManShanksPrime(n, expectedAnswer), "The 1st New Man Shanks prime should be 1.");
+    }
+
+    /**
+     * Test case for the 2nd New Man Shanks prime.
+     * The expected answer is 3.
+     */
+    @Test
+    void testNthManShanksPrime2() {
+        int n = 2;
+        int expectedAnswer = 3;
+        assertTrue(NewManShanksPrime.nthManShanksPrime(n, expectedAnswer), "The 2nd New Man Shanks prime should be 3.");
+    }
+
+    /**
+     * Test case for the 3rd New Man Shanks prime.
+     * The expected answer is 7.
+     */
+    @Test
+    void testNthManShanksPrime3() {
+        int n = 3;
+        int expectedAnswer = 7;
+        assertTrue(NewManShanksPrime.nthManShanksPrime(n, expectedAnswer), "The 3rd New Man Shanks prime should be 7.");
+    }
+
+    /**
+     * Test case for the 4th New Man Shanks prime.
+     * The expected answer is 17.
+     */
+    @Test
+    void testNthManShanksPrime4() {
+        int n = 4;
+        int expectedAnswer = 17;
+        assertTrue(NewManShanksPrime.nthManShanksPrime(n, expectedAnswer), "The 4th New Man Shanks prime should be 17.");
+    }
+
+    /**
+     * Test case for the 5th New Man Shanks prime.
+     * The expected answer is 41.
+     */
+    @Test
+    void testNthManShanksPrime5() {
+        int n = 5;
+        int expectedAnswer = 41;
+        assertTrue(NewManShanksPrime.nthManShanksPrime(n, expectedAnswer), "The 5th New Man Shanks prime should be 41.");
+    }
+
+    /**
+     * Test case with an incorrect expected answer.
+     * For n = 2, the expected answer is 3.
+     */
+    @Test
+    void testNthManShanksPrimeIncorrectAnswer() {
+        int n = 2;
+        int expectedAnswer = 4; // Incorrect expected value
+        assertFalse(NewManShanksPrime.nthManShanksPrime(n, expectedAnswer), "The 2nd New Man Shanks prime should not be 4.");
+    }
+}

From c18dbc43b536e1c9006dbf0ef13808a6ce1698c8 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 10 Oct 2024 23:45:35 +0530
Subject: [PATCH 0489/1338] Add tests, add `IllegalArgumentException` in
 `RodCutting` (#5661)

---
 DIRECTORY.md                                  |  1 +
 .../dynamicprogramming/RodCutting.java        |  4 +
 .../dynamicprogramming/RodCuttingTest.java    | 96 +++++++++++++++++++
 3 files changed, 101 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 4afe7c78e0eb..fb5ff2fed57b 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -824,6 +824,7 @@
             * [PalindromicPartitioningTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioningTest.java)
             * [PartitionProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java)
             * [RegexMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/RegexMatchingTest.java)
+            * [RodCuttingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java)
             * [ShortestCommonSupersequenceLengthTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLengthTest.java)
             * [SubsetCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java)
             * [SubsetSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java b/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
index f56fc4ff5641..76b341e2c823 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
@@ -15,9 +15,13 @@ private RodCutting() {
      * @param price An array representing the prices of different pieces, where price[i-1]
      *              represents the price of a piece of length i.
      * @param n     The length of the rod to be cut.
+     * @throws IllegalArgumentException if the price array is null or empty, or if n is less than 0.
      * @return The maximum obtainable value.
      */
     public static int cutRod(int[] price, int n) {
+        if (price == null || price.length == 0) {
+            throw new IllegalArgumentException("Price array cannot be null or empty.");
+        }
         // Create an array to store the maximum obtainable values for each rod length.
         int[] val = new int[n + 1];
         val[0] = 0;
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java
new file mode 100644
index 000000000000..39497a768397
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java
@@ -0,0 +1,96 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the RodCutting class.
+ * This test class verifies the correctness of the cutRod method for various input cases.
+ */
+class RodCuttingTest {
+
+    /**
+     * Test case for cutting a rod of length 1.
+     * The expected maximum obtainable value is the price of the piece of length 1.
+     */
+    @Test
+    void testCutRodLength1() {
+        int[] prices = {1}; // Price for piece of length 1
+        int length = 1;
+        int expectedValue = 1;
+        assertEquals(expectedValue, RodCutting.cutRod(prices, length), "The maximum obtainable value for a rod of length 1 should be 1.");
+    }
+
+    /**
+     * Test case for cutting a rod of length 2.
+     * The expected maximum obtainable value is the best price combination for length 2.
+     */
+    @Test
+    void testCutRodLength2() {
+        int[] prices = {1, 5}; // Prices for lengths 1 and 2
+        int length = 2;
+        int expectedValue = 5; // Best value is to cut it into a single piece of length 2
+        assertEquals(expectedValue, RodCutting.cutRod(prices, length), "The maximum obtainable value for a rod of length 2 should be 5.");
+    }
+
+    /**
+     * Test case for cutting a rod of length 3.
+     * The expected maximum obtainable value is the best price combination for length 3.
+     */
+    @Test
+    void testCutRodLength3() {
+        int[] prices = {1, 5, 8}; // Prices for lengths 1, 2, and 3
+        int length = 3;
+        int expectedValue = 8; // Best value is to cut it into a single piece of length 3
+        assertEquals(expectedValue, RodCutting.cutRod(prices, length), "The maximum obtainable value for a rod of length 3 should be 8.");
+    }
+
+    /**
+     * Test case for cutting a rod of length 4.
+     * The expected maximum obtainable value is the best price combination for length 4.
+     */
+    @Test
+    void testCutRodLength4() {
+        int[] prices = {1, 5, 8, 9}; // Prices for lengths 1, 2, 3, and 4
+        int length = 4;
+        int expectedValue = 10; // Best value is to cut it into two pieces of length 2
+        assertEquals(expectedValue, RodCutting.cutRod(prices, length), "The maximum obtainable value for a rod of length 4 should be 10.");
+    }
+
+    /**
+     * Test case for cutting a rod of length 5.
+     * The expected maximum obtainable value is the best price combination for length 5.
+     */
+    @Test
+    void testCutRodLength5() {
+        int[] prices = {1, 5, 8, 9, 10}; // Prices for lengths 1, 2, 3, 4, and 5
+        int length = 5;
+        int expectedValue = 13; // Best value is to cut it into pieces of lengths 2 and 3
+        assertEquals(expectedValue, RodCutting.cutRod(prices, length), "The maximum obtainable value for a rod of length 5 should be 13.");
+    }
+
+    /**
+     * Test case for cutting a rod of length 0.
+     * The expected maximum obtainable value should be 0 since the rod has no length.
+     */
+    @Test
+    void testCutRodLength0() {
+        int[] prices = {1, 5, 8, 9, 10}; // Prices are irrelevant for length 0
+        int length = 0;
+        int expectedValue = 0; // No value obtainable from a rod of length 0
+        assertEquals(expectedValue, RodCutting.cutRod(prices, length), "The maximum obtainable value for a rod of length 0 should be 0.");
+    }
+
+    /**
+     * Test case for an empty prices array.
+     * The expected maximum obtainable value should still be 0 for any length.
+     */
+    @Test
+    void testCutRodEmptyPrices() {
+        int[] prices = {};
+        int length = 5;
+        assertThrows(IllegalArgumentException.class, () -> RodCutting.cutRod(prices, length), "An empty prices array should throw an IllegalArgumentException.");
+    }
+}

From ac2c88ca9f60b1d4f97c6e3e9a0bbb87a79dcf84 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 10 Oct 2024 23:49:37 +0530
Subject: [PATCH 0490/1338] =?UTF-8?q?Add=20tests,=20add=20`IllegalArgument?=
 =?UTF-8?q?Exception`,=20remove=20`main`=20in=20`WineProb=E2=80=A6=20(#566?=
 =?UTF-8?q?2)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 DIRECTORY.md                                  |  1 +
 .../dynamicprogramming/WineProblem.java       | 70 ++++++++++++------
 .../dynamicprogramming/WineProblemTest.java   | 72 +++++++++++++++++++
 3 files changed, 120 insertions(+), 23 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/WineProblemTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index fb5ff2fed57b..1e5210730b4d 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -833,6 +833,7 @@
             * [UniquePathsTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java)
             * [UniqueSubsequencesCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCountTest.java)
             * [WildcardMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java)
+            * [WineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WineProblemTest.java)
           * geometry
             * [GrahamScanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
           * greedyalgorithms
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java b/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java
index 0f5359f4d95e..022b43184a88 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java
@@ -1,21 +1,40 @@
 package com.thealgorithms.dynamicprogramming;
 
 /**
- * Imagine you have a collection of N wines placed next to each other on the
- * shelf. The price of ith wine is pi(Prices of different wines are different).
- * Because wine gets better every year supposing today is year 1, on year y the
- * price would be y*pi i.e y times the value of the initial year. You want to
- * sell all wines but you have to sell one wine per year. One more constraint on
- * each year you are allowed to sell either leftmost or rightmost wine on the
- * shelf. You are not allowed to reorder. You have to find the maximum profit
+ * The WineProblem class provides a solution to the wine selling problem.
+ * Given a collection of N wines with different prices, the objective is to maximize profit by selling
+ * one wine each year, considering the constraint that only the leftmost or rightmost wine can be sold
+ * at any given time.
  *
+ * The price of the ith wine is pi, and the selling price increases by a factor of the year in which
+ * it is sold. This class implements three approaches to solve the problem:
+ *
+ * 1. **Recursion**: A straightforward recursive method that computes the maximum profit.
+ *    - Time Complexity: O(2^N)
+ *    - Space Complexity: O(N) due to recursive calls.
+ *
+ * 2. **Top-Down Dynamic Programming (Memoization)**: This approach caches the results of subproblems
+ *    to avoid redundant computations.
+ *    - Time Complexity: O(N^2)
+ *    - Space Complexity: O(N^2) for the storage of results and O(N) for recursion stack.
+ *
+ * 3. **Bottom-Up Dynamic Programming (Tabulation)**: This method builds a table iteratively to
+ *    compute the maximum profit for all possible subproblems.
+ *    - Time Complexity: O(N^2)
+ *    - Space Complexity: O(N^2) for the table.
  */
 public final class WineProblem {
     private WineProblem() {
     }
 
-    // Method 1: Using Recursion
-    // Time Complexity=0(2^N) Space Complexity=Recursion extra space
+    /**
+     * Calculate maximum profit using recursion.
+     *
+     * @param arr Array of wine prices.
+     * @param si  Start index of the wine to consider.
+     * @param ei  End index of the wine to consider.
+     * @return Maximum profit obtainable by selling the wines.
+     */
     public static int wpRecursion(int[] arr, int si, int ei) {
         int n = arr.length;
         int year = (n - (ei - si + 1)) + 1;
@@ -29,8 +48,15 @@ public static int wpRecursion(int[] arr, int si, int ei) {
         return Math.max(start, end);
     }
 
-    // Method 2: Top-Down DP(Memoization)
-    // Time Complexity=0(N*N) Space Complexity=0(N*N)+Recursion extra space
+    /**
+     * Calculate maximum profit using top-down dynamic programming with memoization.
+     *
+     * @param arr  Array of wine prices.
+     * @param si   Start index of the wine to consider.
+     * @param ei   End index of the wine to consider.
+     * @param strg 2D array to store results of subproblems.
+     * @return Maximum profit obtainable by selling the wines.
+     */
     public static int wptd(int[] arr, int si, int ei, int[][] strg) {
         int n = arr.length;
         int year = (n - (ei - si + 1)) + 1;
@@ -45,15 +71,22 @@ public static int wptd(int[] arr, int si, int ei, int[][] strg) {
         int end = wptd(arr, si, ei - 1, strg) + arr[ei] * year;
 
         int ans = Math.max(start, end);
-
         strg[si][ei] = ans;
 
         return ans;
     }
 
-    // Method 3: Bottom-Up DP(Tabulation)
-    // Time Complexity=0(N*N/2)->0(N*N) Space Complexity=0(N*N)
+    /**
+     * Calculate maximum profit using bottom-up dynamic programming with tabulation.
+     *
+     * @param arr Array of wine prices.
+     * @throws IllegalArgumentException if the input array is null or empty.
+     * @return Maximum profit obtainable by selling the wines.
+     */
     public static int wpbu(int[] arr) {
+        if (arr == null || arr.length == 0) {
+            throw new IllegalArgumentException("Input array cannot be null or empty.");
+        }
         int n = arr.length;
         int[][] strg = new int[n][n];
 
@@ -73,13 +106,4 @@ public static int wpbu(int[] arr) {
         }
         return strg[0][n - 1];
     }
-
-    public static void main(String[] args) {
-        int[] arr = {2, 3, 5, 1, 4};
-        System.out.println("Method 1: " + wpRecursion(arr, 0, arr.length - 1));
-        System.out.println("Method 2: " + wptd(arr, 0, arr.length - 1, new int[arr.length][arr.length]));
-        System.out.println("Method 3: " + wpbu(arr));
-    }
 }
-// Memoization vs Tabulation : https://www.geeksforgeeks.org/tabulation-vs-memoization/
-// Question Link : https://www.geeksforgeeks.org/maximum-profit-sale-wines/
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/WineProblemTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/WineProblemTest.java
new file mode 100644
index 000000000000..fbcc2c6f3a83
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/WineProblemTest.java
@@ -0,0 +1,72 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the WineProblem class.
+ * This test class verifies the correctness of the wine selling problem solutions.
+ */
+class WineProblemTest {
+
+    /**
+     * Test for wpRecursion method.
+     */
+    @Test
+    void testWpRecursion() {
+        int[] wines = {2, 3, 5, 1, 4}; // Prices of wines
+        int expectedProfit = 50; // The expected maximum profit
+        assertEquals(expectedProfit, WineProblem.wpRecursion(wines, 0, wines.length - 1), "The maximum profit using recursion should be 50.");
+    }
+
+    /**
+     * Test for wptd method (Top-Down DP with Memoization).
+     */
+    @Test
+    void testWptd() {
+        int[] wines = {2, 3, 5, 1, 4}; // Prices of wines
+        int expectedProfit = 50; // The expected maximum profit
+        assertEquals(expectedProfit, WineProblem.wptd(wines, 0, wines.length - 1, new int[wines.length][wines.length]), "The maximum profit using top-down DP should be 50.");
+    }
+
+    /**
+     * Test for wpbu method (Bottom-Up DP with Tabulation).
+     */
+    @Test
+    void testWpbu() {
+        int[] wines = {2, 3, 5, 1, 4}; // Prices of wines
+        int expectedProfit = 50; // The expected maximum profit
+        assertEquals(expectedProfit, WineProblem.wpbu(wines), "The maximum profit using bottom-up DP should be 50.");
+    }
+
+    /**
+     * Test with a single wine.
+     */
+    @Test
+    void testSingleWine() {
+        int[] wines = {10}; // Only one wine
+        int expectedProfit = 10; // Selling the only wine at year 1
+        assertEquals(expectedProfit, WineProblem.wpbu(wines), "The maximum profit for a single wine should be 10.");
+    }
+
+    /**
+     * Test with multiple wines of the same price.
+     */
+    @Test
+    void testSamePriceWines() {
+        int[] wines = {5, 5, 5}; // All wines have the same price
+        int expectedProfit = 30; // Profit is 5 * (1 + 2 + 3)
+        assertEquals(expectedProfit, WineProblem.wpbu(wines), "The maximum profit with same price wines should be 30.");
+    }
+
+    /**
+     * Test with no wines.
+     */
+    @Test
+    void testNoWines() {
+        int[] wines = {};
+        assertThrows(IllegalArgumentException.class, () -> WineProblem.wpbu(wines), "The maximum profit for no wines should throw an IllegalArgumentException.");
+    }
+}

From ca5fbbf0a9748680cb1bf56b19ffc7b026b4c3ed Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 00:52:42 +0530
Subject: [PATCH 0491/1338] Add tests, remove `main` in `BinarySearch` (#5663)

---
 DIRECTORY.md                                  |   1 +
 .../thealgorithms/searches/BinarySearch.java  |  26 -----
 .../searches/BinarySearchTest.java            | 108 ++++++++++++++++++
 3 files changed, 109 insertions(+), 26 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/BinarySearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 1e5210730b4d..cc4e90a4ffdc 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -997,6 +997,7 @@
             * [SRTFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java)
           * searches
             * [BinarySearch2dArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java)
+            * [BinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BinarySearchTest.java)
             * [BM25InvertedIndexTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java)
             * [BreadthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java)
             * [DepthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/BinarySearch.java b/src/main/java/com/thealgorithms/searches/BinarySearch.java
index 22096307d144..bedad1667f33 100644
--- a/src/main/java/com/thealgorithms/searches/BinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/BinarySearch.java
@@ -1,10 +1,6 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
-import java.util.Arrays;
-import java.util.Random;
-import java.util.concurrent.ThreadLocalRandom;
-import java.util.stream.IntStream;
 
 /**
  * Binary search is one of the most popular algorithms The algorithm finds the
@@ -57,26 +53,4 @@ private <T extends Comparable<T>> int search(T[] array, T key, int left, int rig
             return search(array, key, median + 1, right);
         }
     }
-
-    // Driver Program
-    public static void main(String[] args) {
-        // Just generate data
-        Random r = ThreadLocalRandom.current();
-
-        int size = 100;
-        int maxElement = 100000;
-
-        Integer[] integers = IntStream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().boxed().toArray(Integer[] ::new);
-
-        // The element that should be found
-        int shouldBeFound = integers[r.nextInt(size - 1)];
-
-        BinarySearch search = new BinarySearch();
-        int atIndex = search.find(integers, shouldBeFound);
-
-        System.out.printf("Should be found: %d. Found %d at index %d. An array length %d%n", shouldBeFound, integers[atIndex], atIndex, size);
-
-        int toCheck = Arrays.binarySearch(integers, shouldBeFound);
-        System.out.printf("Found by system method at an index: %d. Is equal: %b%n", toCheck, toCheck == atIndex);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/searches/BinarySearchTest.java b/src/test/java/com/thealgorithms/searches/BinarySearchTest.java
new file mode 100644
index 000000000000..bd4620a7fa7d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/BinarySearchTest.java
@@ -0,0 +1,108 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.IntStream;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the BinarySearch class.
+ */
+class BinarySearchTest {
+
+    /**
+     * Test for basic binary search functionality.
+     */
+    @Test
+    void testBinarySearchFound() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        int key = 7;
+        int expectedIndex = 6; // Index of the key in the array
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The index of the found element should be 6.");
+    }
+
+    /**
+     * Test for binary search when the element is not present.
+     */
+    @Test
+    void testBinarySearchNotFound() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {1, 2, 3, 4, 5};
+        int key = 6; // Element not present in the array
+        int expectedIndex = -1; // Key not found
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for binary search with first element as the key.
+     */
+    @Test
+    void testBinarySearchFirstElement() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {1, 2, 3, 4, 5};
+        int key = 1; // First element
+        int expectedIndex = 0; // Index of the key in the array
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The index of the first element should be 0.");
+    }
+
+    /**
+     * Test for binary search with last element as the key.
+     */
+    @Test
+    void testBinarySearchLastElement() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {1, 2, 3, 4, 5};
+        int key = 5; // Last element
+        int expectedIndex = 4; // Index of the key in the array
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The index of the last element should be 4.");
+    }
+
+    /**
+     * Test for binary search with a single element present.
+     */
+    @Test
+    void testBinarySearchSingleElementFound() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {1};
+        int key = 1; // Only element present
+        int expectedIndex = 0; // Index of the key in the array
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The index of the single element should be 0.");
+    }
+
+    /**
+     * Test for binary search with a single element not present.
+     */
+    @Test
+    void testBinarySearchSingleElementNotFound() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {1};
+        int key = 2; // Key not present
+        int expectedIndex = -1; // Key not found
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for binary search with an empty array.
+     */
+    @Test
+    void testBinarySearchEmptyArray() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {}; // Empty array
+        int key = 1; // Key not present
+        int expectedIndex = -1; // Key not found
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The element should not be found in an empty array.");
+    }
+
+    /**
+     * Test for binary search on large array.
+     */
+    @Test
+    void testBinarySearchLargeArray() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = IntStream.range(0, 10000).boxed().toArray(Integer[] ::new); // Array from 0 to 9999
+        int key = 9999; // Last element
+        int expectedIndex = 9999; // Index of the last element
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The index of the last element should be 9999.");
+    }
+}

From a4e431912641cb0480412a7910fc318a6e6f016c Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 00:56:16 +0530
Subject: [PATCH 0492/1338] Add tests, remove `main`, improve docs in
 `FibonacciSearch` (#5665)

---
 DIRECTORY.md                                  |   1 +
 .../searches/FibonacciSearch.java             |  55 +++++---
 .../searches/FibonacciSearchTest.java         | 124 ++++++++++++++++++
 3 files changed, 160 insertions(+), 20 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index cc4e90a4ffdc..0726337c3f22 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1001,6 +1001,7 @@
             * [BM25InvertedIndexTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java)
             * [BreadthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java)
             * [DepthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java)
+            * [FibonacciSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java)
             * [HowManyTimesRotatedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java)
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/FibonacciSearch.java b/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
index 028ab07e0a86..2124938bc258 100644
--- a/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
+++ b/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
@@ -2,24 +2,42 @@
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
 
-/*
- *  Fibonacci Search is a popular algorithm which finds the position of a target value in
- *  a sorted array
+/**
+ * FibonacciSearch is a search algorithm that finds the position of a target value in
+ * a sorted array using Fibonacci numbers.
  *
- *  The time complexity for this search algorithm is O(log3(n))
- *  The space complexity for this search algorithm is O(1)
- *  @author Kanakalatha Vemuru (https://github.com/KanakalathaVemuru)
+ * <p>
+ * The time complexity for this search algorithm is O(log n).
+ * The space complexity for this search algorithm is O(1).
+ * </p>
+ *
+ * <p>
+ * Note: This algorithm requires that the input array be sorted.
+ * </p>
  */
 public class FibonacciSearch implements SearchAlgorithm {
 
     /**
-     * @param array is a sorted array where the element has to be searched
-     * @param key is an element whose position has to be found
-     * @param <T> is any comparable type
-     * @return index of the element
+     * Finds the index of the specified key in a sorted array using Fibonacci search.
+     *
+     * @param array The sorted array to search.
+     * @param key The element to search for.
+     * @param <T> The type of the elements in the array, which must be comparable.
+     * @throws IllegalArgumentException if the input array is not sorted or empty, or if the key is null.
+     * @return The index of the key if found, otherwise -1.
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
+        if (array.length == 0) {
+            throw new IllegalArgumentException("Input array must not be empty.");
+        }
+        if (!isSorted(array)) {
+            throw new IllegalArgumentException("Input array must be sorted.");
+        }
+        if (key == null) {
+            throw new IllegalArgumentException("Key must not be null.");
+        }
+
         int fibMinus1 = 1;
         int fibMinus2 = 0;
         int fibNumber = fibMinus1 + fibMinus2;
@@ -57,15 +75,12 @@ public <T extends Comparable<T>> int find(T[] array, T key) {
         return -1;
     }
 
-    // Driver Program
-    public static void main(String[] args) {
-        Integer[] integers = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512};
-
-        int size = integers.length;
-        Integer targetValue = 128;
-        FibonacciSearch fsearch = new FibonacciSearch();
-        int atIndex = fsearch.find(integers, targetValue);
-
-        System.out.println("Should be found: " + targetValue + ". Found " + integers[atIndex] + " at index " + atIndex + ". An array length " + size);
+    private boolean isSorted(Comparable[] array) {
+        for (int i = 1; i < array.length; i++) {
+            if (array[i - 1].compareTo(array[i]) > 0) {
+                return false;
+            }
+        }
+        return true;
     }
 }
diff --git a/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java b/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java
new file mode 100644
index 000000000000..801c33b1d09a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java
@@ -0,0 +1,124 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.IntStream;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the FibonacciSearch class.
+ */
+class FibonacciSearchTest {
+
+    /**
+     * Test for basic Fibonacci search functionality.
+     */
+    @Test
+    void testFibonacciSearchFound() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512};
+        int key = 128;
+        int expectedIndex = 7; // Index of the key in the array
+        assertEquals(expectedIndex, fibonacciSearch.find(array, key), "The index of the found element should be 7.");
+    }
+
+    /**
+     * Test for Fibonacci search when the element is not present.
+     */
+    @Test
+    void testFibonacciSearchNotFound() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        int key = 6; // Element not present in the array
+        int expectedIndex = -1; // Key not found
+        assertEquals(expectedIndex, fibonacciSearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for Fibonacci search with the first element as the key.
+     */
+    @Test
+    void testFibonacciSearchFirstElement() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        int key = 1; // First element
+        int expectedIndex = 0; // Index of the key in the array
+        assertEquals(expectedIndex, fibonacciSearch.find(array, key), "The index of the first element should be 0.");
+    }
+
+    /**
+     * Test for Fibonacci search with the last element as the key.
+     */
+    @Test
+    void testFibonacciSearchLastElement() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        int key = 16; // Last element
+        int expectedIndex = 4; // Index of the key in the array
+        assertEquals(expectedIndex, fibonacciSearch.find(array, key), "The index of the last element should be 4.");
+    }
+
+    /**
+     * Test for Fibonacci search with a single element present.
+     */
+    @Test
+    void testFibonacciSearchSingleElementFound() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = {1};
+        int key = 1; // Only element present
+        int expectedIndex = 0; // Index of the key in the array
+        assertEquals(expectedIndex, fibonacciSearch.find(array, key), "The index of the single element should be 0.");
+    }
+
+    /**
+     * Test for Fibonacci search with a single element not present.
+     */
+    @Test
+    void testFibonacciSearchSingleElementNotFound() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = {1};
+        int key = 2; // Key not present
+        int expectedIndex = -1; // Key not found
+        assertEquals(expectedIndex, fibonacciSearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for Fibonacci search with an empty array.
+     */
+    @Test
+    void testFibonacciSearchEmptyArray() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = {}; // Empty array
+        int key = 1; // Key not present
+        assertThrows(IllegalArgumentException.class, () -> fibonacciSearch.find(array, key), "An empty array should throw an IllegalArgumentException.");
+    }
+
+    @Test
+    void testFibonacciSearchUnsortedArray() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = {2, 1, 4, 3, 6, 5};
+        int key = 3; // Key not present
+        assertThrows(IllegalArgumentException.class, () -> fibonacciSearch.find(array, key), "An unsorted array should throw an IllegalArgumentException.");
+    }
+
+    @Test
+    void testFibonacciSearchNullKey() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        Integer key = null; // Null key
+        assertThrows(IllegalArgumentException.class, () -> fibonacciSearch.find(array, key), "A null key should throw an IllegalArgumentException.");
+    }
+
+    /**
+     * Test for Fibonacci search on large array.
+     */
+    @Test
+    void testFibonacciSearchLargeArray() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = IntStream.range(0, 10000).boxed().toArray(Integer[] ::new); // Array from 0 to 9999
+        int key = 9999;
+        int expectedIndex = 9999;
+        assertEquals(expectedIndex, fibonacciSearch.find(array, key), "The index of the last element should be 9999.");
+    }
+}

From d197fc7df2947e9e0758e32939fb19a109e68588 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:00:37 +0530
Subject: [PATCH 0493/1338] Add tests, remove `main`, improve docs in
 `ExponentialSearch` (#5664)

---
 DIRECTORY.md                                  |  1 +
 .../searches/ExponentalSearch.java            | 59 ++++++-------
 .../searches/ExponentialSearchTest.java       | 84 +++++++++++++++++++
 3 files changed, 116 insertions(+), 28 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0726337c3f22..7690d09add9b 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1001,6 +1001,7 @@
             * [BM25InvertedIndexTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java)
             * [BreadthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java)
             * [DepthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java)
+            * [ExponentialSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java)
             * [FibonacciSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java)
             * [HowManyTimesRotatedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java)
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/ExponentalSearch.java b/src/main/java/com/thealgorithms/searches/ExponentalSearch.java
index a856bd659720..9187dcbc2f4b 100644
--- a/src/main/java/com/thealgorithms/searches/ExponentalSearch.java
+++ b/src/main/java/com/thealgorithms/searches/ExponentalSearch.java
@@ -2,44 +2,47 @@
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
 import java.util.Arrays;
-import java.util.Random;
-import java.util.concurrent.ThreadLocalRandom;
-import java.util.stream.IntStream;
 
+/**
+ * ExponentialSearch is an algorithm that efficiently finds the position of a target
+ * value within a sorted array. It works by expanding the range to find the bounds
+ * where the target might exist and then using binary search within that range.
+ *
+ * <p>
+ * Worst-case time complexity: O(log n)
+ * Best-case time complexity: O(1) when the element is found at the first position.
+ * Average time complexity: O(log n)
+ * Worst-case space complexity: O(1)
+ * </p>
+ *
+ * <p>
+ * Note: This algorithm requires that the input array be sorted.
+ * </p>
+ */
 class ExponentialSearch implements SearchAlgorithm {
 
-    public static void main(String[] args) {
-        Random r = ThreadLocalRandom.current();
-
-        int size = 100;
-        int maxElement = 100000;
-
-        Integer[] integers = IntStream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().boxed().toArray(Integer[] ::new);
-
-        // The element that should be found
-        int shouldBeFound = integers[r.nextInt(size - 1)];
-
-        ExponentialSearch search = new ExponentialSearch();
-        int atIndex = search.find(integers, shouldBeFound);
-
-        System.out.printf("Should be found: %d. Found %d at index %d. An array length %d%n", shouldBeFound, integers[atIndex], atIndex, size);
-
-        int toCheck = Arrays.binarySearch(integers, shouldBeFound);
-        System.out.printf("Found by system method at an index: %d. Is equal: %b%n", toCheck, toCheck == atIndex);
-    }
-
+    /**
+     * Finds the index of the specified key in a sorted array using exponential search.
+     *
+     * @param array The sorted array to search.
+     * @param key The element to search for.
+     * @param <T> The type of the elements in the array, which must be comparable.
+     * @return The index of the key if found, otherwise -1.
+     */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
-        if (array[0] == key) {
+        if (array.length == 0) {
+            return -1;
+        }
+        if (array[0].equals(key)) {
             return 0;
         }
-        if (array[array.length - 1] == key) {
-            return array.length;
+        if (array[array.length - 1].equals(key)) {
+            return array.length - 1;
         }
 
         int range = 1;
-
-        while (range < array.length && array[range].compareTo(key) <= -1) {
+        while (range < array.length && array[range].compareTo(key) < 0) {
             range = range * 2;
         }
 
diff --git a/src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java b/src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java
new file mode 100644
index 000000000000..c84da531e8a4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java
@@ -0,0 +1,84 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.IntStream;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the ExponentialSearch class.
+ */
+class ExponentialSearchTest {
+
+    /**
+     * Test for basic exponential search functionality.
+     */
+    @Test
+    void testExponentialSearchFound() {
+        ExponentialSearch exponentialSearch = new ExponentialSearch();
+        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        int key = 7;
+        int expectedIndex = 6; // Index of the key in the array
+        assertEquals(expectedIndex, exponentialSearch.find(array, key), "The index of the found element should be 6.");
+    }
+
+    /**
+     * Test for exponential search with the first element as the key.
+     */
+    @Test
+    void testExponentialSearchFirstElement() {
+        ExponentialSearch exponentialSearch = new ExponentialSearch();
+        Integer[] array = {1, 2, 3, 4, 5};
+        int key = 1; // First element
+        int expectedIndex = 0; // Index of the key in the array
+        assertEquals(expectedIndex, exponentialSearch.find(array, key), "The index of the first element should be 0.");
+    }
+
+    /**
+     * Test for exponential search with the last element as the key.
+     */
+    @Test
+    void testExponentialSearchLastElement() {
+        ExponentialSearch exponentialSearch = new ExponentialSearch();
+        Integer[] array = {1, 2, 3, 4, 5};
+        int key = 5; // Last element
+        int expectedIndex = 4; // Index of the key in the array
+        assertEquals(expectedIndex, exponentialSearch.find(array, key), "The index of the last element should be 4.");
+    }
+
+    /**
+     * Test for exponential search with a single element present.
+     */
+    @Test
+    void testExponentialSearchSingleElementFound() {
+        ExponentialSearch exponentialSearch = new ExponentialSearch();
+        Integer[] array = {1};
+        int key = 1; // Only element present
+        int expectedIndex = 0; // Index of the key in the array
+        assertEquals(expectedIndex, exponentialSearch.find(array, key), "The index of the single element should be 0.");
+    }
+
+    /**
+     * Test for exponential search with an empty array.
+     */
+    @Test
+    void testExponentialSearchEmptyArray() {
+        ExponentialSearch exponentialSearch = new ExponentialSearch();
+        Integer[] array = {}; // Empty array
+        int key = 1; // Key not present
+        int expectedIndex = -1; // Key not found
+        assertEquals(expectedIndex, exponentialSearch.find(array, key), "The element should not be found in an empty array.");
+    }
+
+    /**
+     * Test for exponential search on large array.
+     */
+    @Test
+    void testExponentialSearchLargeArray() {
+        ExponentialSearch exponentialSearch = new ExponentialSearch();
+        Integer[] array = IntStream.range(0, 10000).boxed().toArray(Integer[] ::new); // Array from 0 to 9999
+        int key = 9999;
+        int expectedIndex = 9999;
+        assertEquals(expectedIndex, exponentialSearch.find(array, key), "The index of the last element should be 9999.");
+    }
+}

From ba3d3bf54e3994f9accf7f7345815e80c7bd386b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:06:38 +0530
Subject: [PATCH 0494/1338] Add tests, remove `main`, improve docs in
 `InterpolationSearch` (#5666)

---
 DIRECTORY.md                                  |  1 +
 .../searches/InterpolationSearch.java         | 47 ++++------
 .../searches/InterpolationSearchTest.java     | 90 +++++++++++++++++++
 3 files changed, 108 insertions(+), 30 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7690d09add9b..a23a6f03f02b 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1004,6 +1004,7 @@
             * [ExponentialSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java)
             * [FibonacciSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java)
             * [HowManyTimesRotatedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java)
+            * [InterpolationSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java)
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
             * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/InterpolationSearch.java b/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
index aa1ff412b6a7..3ac6be25bf53 100644
--- a/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
+++ b/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
@@ -1,25 +1,31 @@
 package com.thealgorithms.searches;
 
-import java.util.Arrays;
-import java.util.Random;
-import java.util.stream.IntStream;
-
 /**
- * Interpolation search algorithm implementation
+ * InterpolationSearch is an algorithm that searches for a target value within a sorted array
+ * by estimating the position based on the values at the corners of the current search range.
+ *
+ * <p>
+ * The performance of this algorithm can vary:
+ * - Worst-case performance: O(n)
+ * - Best-case performance: O(1)
+ * - Average performance: O(log(log(n))) if the elements are uniformly distributed; otherwise O(n)
+ * - Worst-case space complexity: O(1)
+ * </p>
  *
  * <p>
- * Worst-case performance O(n) Best-case performance O(1) Average performance
- * O(log(log(n))) if the elements are uniformly distributed if not O(n)
- * Worst-case space complexity O(1)
+ * This search algorithm requires the input array to be sorted.
+ * </p>
  *
  * @author Podshivalov Nikita (https://github.com/nikitap492)
  */
 class InterpolationSearch {
 
     /**
-     * @param array is a sorted array
-     * @param key is a value what shoulb be found in the array
-     * @return an index if the array contains the key unless -1
+     * Finds the index of the specified key in a sorted array using interpolation search.
+     *
+     * @param array The sorted array to search.
+     * @param key The value to search for.
+     * @return The index of the key if found, otherwise -1.
      */
     public int find(int[] array, int key) {
         // Find indexes of two corners
@@ -48,23 +54,4 @@ public int find(int[] array, int key) {
         }
         return -1;
     }
-
-    // Driver method
-    public static void main(String[] args) {
-        Random r = new Random();
-        int size = 100;
-        int maxElement = 100000;
-        int[] integers = IntStream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().toArray();
-
-        // the element that should be found
-        int shouldBeFound = integers[r.nextInt(size - 1)];
-
-        InterpolationSearch search = new InterpolationSearch();
-        int atIndex = search.find(integers, shouldBeFound);
-
-        System.out.printf("Should be found: %d. Found %d at index %d. An array length %d%n", shouldBeFound, integers[atIndex], atIndex, size);
-
-        int toCheck = Arrays.binarySearch(integers, shouldBeFound);
-        System.out.printf("Found by system method at an index: %d. Is equal: %b%n", toCheck, toCheck == atIndex);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java b/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java
new file mode 100644
index 000000000000..b3b7e7ef129c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java
@@ -0,0 +1,90 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.IntStream;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the InterpolationSearch class.
+ */
+class InterpolationSearchTest {
+
+    /**
+     * Test for basic interpolation search functionality when the element is found.
+     */
+    @Test
+    void testInterpolationSearchFound() {
+        InterpolationSearch interpolationSearch = new InterpolationSearch();
+        int[] array = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512};
+        int key = 128;
+        int expectedIndex = 7; // Index of the key in the array
+        assertEquals(expectedIndex, interpolationSearch.find(array, key), "The index of the found element should be 7.");
+    }
+
+    /**
+     * Test for interpolation search when the element is not present in the array.
+     */
+    @Test
+    void testInterpolationSearchNotFound() {
+        InterpolationSearch interpolationSearch = new InterpolationSearch();
+        int[] array = {1, 2, 4, 8, 16};
+        int key = 6; // Element not present in the array
+        assertEquals(-1, interpolationSearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for interpolation search with the first element as the key.
+     */
+    @Test
+    void testInterpolationSearchFirstElement() {
+        InterpolationSearch interpolationSearch = new InterpolationSearch();
+        int[] array = {1, 2, 4, 8, 16};
+        int key = 1; // First element
+        assertEquals(0, interpolationSearch.find(array, key), "The index of the first element should be 0.");
+    }
+
+    /**
+     * Test for interpolation search with a single element not present.
+     */
+    @Test
+    void testInterpolationSearchSingleElementNotFound() {
+        InterpolationSearch interpolationSearch = new InterpolationSearch();
+        int[] array = {1};
+        int key = 2; // Key not present
+        assertEquals(-1, interpolationSearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for interpolation search with an empty array.
+     */
+    @Test
+    void testInterpolationSearchEmptyArray() {
+        InterpolationSearch interpolationSearch = new InterpolationSearch();
+        int[] array = {}; // Empty array
+        int key = 1; // Key not present
+        assertEquals(-1, interpolationSearch.find(array, key), "The element should not be found in an empty array.");
+    }
+
+    /**
+     * Test for interpolation search on large uniformly distributed array.
+     */
+    @Test
+    void testInterpolationSearchLargeUniformArray() {
+        InterpolationSearch interpolationSearch = new InterpolationSearch();
+        int[] array = IntStream.range(0, 10000).map(i -> i * 2).toArray(); // Array from 0 to 19998, step 2
+        int key = 9998; // Last even number in the array
+        assertEquals(4999, interpolationSearch.find(array, key), "The index of the last element should be 4999.");
+    }
+
+    /**
+     * Test for interpolation search on large non-uniformly distributed array.
+     */
+    @Test
+    void testInterpolationSearchLargeNonUniformArray() {
+        InterpolationSearch interpolationSearch = new InterpolationSearch();
+        int[] array = {1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144}; // Fibonacci numbers
+        int key = 21; // Present in the array
+        assertEquals(6, interpolationSearch.find(array, key), "The index of the found element should be 6.");
+    }
+}

From 0a7065df38cbc16ebc6ce45fc6a07bdcc1eb491d Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:11:07 +0530
Subject: [PATCH 0495/1338] Add tests, remove `main` in `IterativeBinarySearch`
 (#5667)

---
 DIRECTORY.md                                  |   1 +
 .../searches/IterativeBinarySearch.java       |  22 ----
 .../searches/IterativeBinarySearchTest.java   | 117 ++++++++++++++++++
 3 files changed, 118 insertions(+), 22 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a23a6f03f02b..23f2941a702c 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1005,6 +1005,7 @@
             * [FibonacciSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java)
             * [HowManyTimesRotatedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java)
             * [InterpolationSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java)
+            * [IterativeBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java)
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
             * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java b/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
index 49a86e4e53a8..05fab0534267 100644
--- a/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
@@ -1,9 +1,6 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
-import java.util.Arrays;
-import java.util.Random;
-import java.util.stream.Stream;
 
 /**
  * Binary search is one of the most popular algorithms This class represents
@@ -55,23 +52,4 @@ public <T extends Comparable<T>> int find(T[] array, T key) {
 
         return -1;
     }
-
-    // Only a main method for test purpose
-    public static void main(String[] args) {
-        Random r = new Random();
-        int size = 100;
-        int maxElement = 100000;
-        Integer[] integers = Stream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().toArray(Integer[] ::new);
-
-        // the element that should be found
-        Integer shouldBeFound = integers[r.nextInt(size - 1)];
-
-        IterativeBinarySearch search = new IterativeBinarySearch();
-        int atIndex = search.find(integers, shouldBeFound);
-
-        System.out.printf("Should be found: %d. Found %d at index %d. An array length %d%n", shouldBeFound, integers[atIndex], atIndex, size);
-
-        int toCheck = Arrays.binarySearch(integers, shouldBeFound);
-        System.out.printf("Found by system method at an index: %d. Is equal: %b%n", toCheck, toCheck == atIndex);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java
new file mode 100644
index 000000000000..b2e121ac1ba0
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java
@@ -0,0 +1,117 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the IterativeBinarySearch class.
+ */
+class IterativeBinarySearchTest {
+
+    /**
+     * Test for basic binary search functionality when the element is found.
+     */
+    @Test
+    void testBinarySearchFound() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer[] array = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512};
+        Integer key = 128;
+        int expectedIndex = 7; // Index of the key in the array
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The index of the found element should be 7.");
+    }
+
+    /**
+     * Test for binary search when the element is not present in the array.
+     */
+    @Test
+    void testBinarySearchNotFound() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        Integer key = 6; // Element not present in the array
+        assertEquals(-1, binarySearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for binary search with the first element as the key.
+     */
+    @Test
+    void testBinarySearchFirstElement() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        Integer key = 1; // First element
+        assertEquals(0, binarySearch.find(array, key), "The index of the first element should be 0.");
+    }
+
+    /**
+     * Test for binary search with the last element as the key.
+     */
+    @Test
+    void testBinarySearchLastElement() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        Integer key = 16; // Last element
+        assertEquals(4, binarySearch.find(array, key), "The index of the last element should be 4.");
+    }
+
+    /**
+     * Test for binary search with a single element present.
+     */
+    @Test
+    void testBinarySearchSingleElementFound() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer[] array = {1};
+        Integer key = 1; // Only element present
+        assertEquals(0, binarySearch.find(array, key), "The index of the single element should be 0.");
+    }
+
+    /**
+     * Test for binary search with a single element not present.
+     */
+    @Test
+    void testBinarySearchSingleElementNotFound() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer[] array = {1};
+        Integer key = 2; // Key not present
+        assertEquals(-1, binarySearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for binary search with an empty array.
+     */
+    @Test
+    void testBinarySearchEmptyArray() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer[] array = {}; // Empty array
+        Integer key = 1; // Key not present
+        assertEquals(-1, binarySearch.find(array, key), "The element should not be found in an empty array.");
+    }
+
+    /**
+     * Test for binary search on a large array.
+     */
+    @Test
+    void testBinarySearchLargeArray() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer[] array = new Integer[10000];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = i * 2;
+        } // Array from 0 to 19998, step 2
+        Integer key = 9998; // Present in the array
+        assertEquals(4999, binarySearch.find(array, key), "The index of the found element should be 4999.");
+    }
+
+    /**
+     * Test for binary search on large array with a non-existent key.
+     */
+    @Test
+    void testBinarySearchLargeArrayNotFound() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer[] array = new Integer[10000];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = i * 2;
+        } // Array from 0 to 19998, step 2
+        Integer key = 9999; // Key not present
+        assertEquals(-1, binarySearch.find(array, key), "The element should not be found in the array.");
+    }
+}

From f992fc425df914403475a35d700e09f67b69a8a4 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:15:26 +0530
Subject: [PATCH 0496/1338] Add tests, remove main in IterativeTernarySearch
 (#5668)

---
 DIRECTORY.md                                  |   1 +
 .../searches/IterativeTernarySearch.java      |  52 ++++----
 .../searches/IterativeTernarySearchTest.java  | 117 ++++++++++++++++++
 3 files changed, 140 insertions(+), 30 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/IterativeTernarySearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 23f2941a702c..ff6e29806847 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1006,6 +1006,7 @@
             * [HowManyTimesRotatedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java)
             * [InterpolationSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java)
             * [IterativeBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java)
+            * [IterativeTernarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/IterativeTernarySearchTest.java)
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
             * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/IterativeTernarySearch.java b/src/main/java/com/thealgorithms/searches/IterativeTernarySearch.java
index e78acd6a7ef8..585d6787d3f8 100644
--- a/src/main/java/com/thealgorithms/searches/IterativeTernarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/IterativeTernarySearch.java
@@ -1,22 +1,26 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
-import java.util.Arrays;
-import java.util.Random;
-import java.util.stream.Stream;
 
 /**
- * A iterative version of a ternary search algorithm This is better way to
- * implement the ternary search, because a recursive version adds some overhead
- * to a stack. But in java the compile can transform the recursive version to
- * iterative implicitly, so there are no much differences between these two
- * algorithms
+ * An iterative implementation of the Ternary Search algorithm.
  *
  * <p>
- * Worst-case performance Θ(log3(N)) Best-case performance O(1) Average
- * performance Θ(log3(N)) Worst-case space complexity O(1)
+ * Ternary search is a divide-and-conquer algorithm that splits the array into three parts
+ * instead of two, as in binary search. This implementation is iterative, reducing the overhead
+ * associated with recursive function calls. However, the recursive version can also be optimized
+ * by the Java compiler to resemble the iterative version, resulting in similar performance.
+ *
+ * <p>
+ * Worst-case performance: Θ(log3(N))<br>
+ * Best-case performance: O(1)<br>
+ * Average performance: Θ(log3(N))<br>
+ * Worst-case space complexity: O(1)
+ *
+ * <p>
+ * This class implements the {@link SearchAlgorithm} interface, providing a generic search method
+ * for any comparable type.
  *
- * @author Podshivalov Nikita (https://github.com/nikitap492)
  * @see SearchAlgorithm
  * @see TernarySearch
  * @since 2018-04-13
@@ -25,6 +29,13 @@ public class IterativeTernarySearch implements SearchAlgorithm {
 
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
+        if (array == null || array.length == 0 || key == null) {
+            return -1;
+        }
+        if (array.length == 1) {
+            return array[0].compareTo(key) == 0 ? 0 : -1;
+        }
+
         int left = 0;
         int right = array.length - 1;
 
@@ -50,23 +61,4 @@ public <T extends Comparable<T>> int find(T[] array, T key) {
 
         return -1;
     }
-
-    public static void main(String[] args) {
-        // just generate data
-        Random r = new Random();
-        int size = 100;
-        int maxElement = 100000;
-        Integer[] integers = Stream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().toArray(Integer[] ::new);
-
-        // the element that should be found
-        Integer shouldBeFound = integers[r.nextInt(size - 1)];
-
-        IterativeTernarySearch search = new IterativeTernarySearch();
-        int atIndex = search.find(integers, shouldBeFound);
-
-        System.out.printf("Should be found: %d. Found %d at index %d. An array length %d%n", shouldBeFound, integers[atIndex], atIndex, size);
-
-        int toCheck = Arrays.binarySearch(integers, shouldBeFound);
-        System.out.printf("Found by system method at an index: %d. Is equal: %b%n", toCheck, toCheck == atIndex);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/searches/IterativeTernarySearchTest.java b/src/test/java/com/thealgorithms/searches/IterativeTernarySearchTest.java
new file mode 100644
index 000000000000..c7640e6d0672
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/IterativeTernarySearchTest.java
@@ -0,0 +1,117 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the IterativeTernarySearch class.
+ */
+class IterativeTernarySearchTest {
+
+    /**
+     * Test for basic ternary search functionality when the element is found.
+     */
+    @Test
+    void testTernarySearchFound() {
+        IterativeTernarySearch ternarySearch = new IterativeTernarySearch();
+        Integer[] array = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512};
+        Integer key = 128;
+        int expectedIndex = 7; // Index of the key in the array
+        assertEquals(expectedIndex, ternarySearch.find(array, key), "The index of the found element should be 7.");
+    }
+
+    /**
+     * Test for ternary search when the element is not present in the array.
+     */
+    @Test
+    void testTernarySearchNotFound() {
+        IterativeTernarySearch ternarySearch = new IterativeTernarySearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        Integer key = 6; // Element not present in the array
+        assertEquals(-1, ternarySearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for ternary search with the first element as the key.
+     */
+    @Test
+    void testTernarySearchFirstElement() {
+        IterativeTernarySearch ternarySearch = new IterativeTernarySearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        Integer key = 1; // First element
+        assertEquals(0, ternarySearch.find(array, key), "The index of the first element should be 0.");
+    }
+
+    /**
+     * Test for ternary search with the last element as the key.
+     */
+    @Test
+    void testTernarySearchLastElement() {
+        IterativeTernarySearch ternarySearch = new IterativeTernarySearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        Integer key = 16; // Last element
+        assertEquals(4, ternarySearch.find(array, key), "The index of the last element should be 4.");
+    }
+
+    /**
+     * Test for ternary search with a single element present.
+     */
+    @Test
+    void testTernarySearchSingleElementFound() {
+        IterativeTernarySearch ternarySearch = new IterativeTernarySearch();
+        Integer[] array = {1};
+        Integer key = 1; // Only element present
+        assertEquals(0, ternarySearch.find(array, key), "The index of the single element should be 0.");
+    }
+
+    /**
+     * Test for ternary search with a single element not present.
+     */
+    @Test
+    void testTernarySearchSingleElementNotFound() {
+        IterativeTernarySearch ternarySearch = new IterativeTernarySearch();
+        Integer[] array = {1};
+        Integer key = 2; // Key not present
+        assertEquals(-1, ternarySearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for ternary search with an empty array.
+     */
+    @Test
+    void testTernarySearchEmptyArray() {
+        IterativeTernarySearch ternarySearch = new IterativeTernarySearch();
+        Integer[] array = {}; // Empty array
+        Integer key = 1; // Key not present
+        assertEquals(-1, ternarySearch.find(array, key), "The element should not be found in an empty array.");
+    }
+
+    /**
+     * Test for ternary search on a large array.
+     */
+    @Test
+    void testTernarySearchLargeArray() {
+        IterativeTernarySearch ternarySearch = new IterativeTernarySearch();
+        Integer[] array = new Integer[10000];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = i * 2;
+        } // Array from 0 to 19998, step 2
+        Integer key = 9998; // Present in the array
+        assertEquals(4999, ternarySearch.find(array, key), "The index of the found element should be 4999.");
+    }
+
+    /**
+     * Test for ternary search on large array with a non-existent key.
+     */
+    @Test
+    void testTernarySearchLargeArrayNotFound() {
+        IterativeTernarySearch ternarySearch = new IterativeTernarySearch();
+        Integer[] array = new Integer[10000];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = i * 2;
+        } // Array from 0 to 19998, step 2
+        Integer key = 9999; // Key not present
+        assertEquals(-1, ternarySearch.find(array, key), "The element should not be found in the array.");
+    }
+}

From 38285771c8bf1e4bf1c3741d4ce397d744b01136 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:21:06 +0530
Subject: [PATCH 0497/1338] Add tests, remove main in JumpSearch (#5669)

---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/searches/JumpSearch.java    | 55 ++++++-----
 .../searches/JumpSearchTest.java              | 94 +++++++++++++++++++
 3 files changed, 128 insertions(+), 22 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/JumpSearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index ff6e29806847..a22863e8b052 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1007,6 +1007,7 @@
             * [InterpolationSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java)
             * [IterativeBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java)
             * [IterativeTernarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/IterativeTernarySearchTest.java)
+            * [JumpSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/JumpSearchTest.java)
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
             * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/JumpSearch.java b/src/main/java/com/thealgorithms/searches/JumpSearch.java
index f499cf8079cc..8dcec3a819a4 100644
--- a/src/main/java/com/thealgorithms/searches/JumpSearch.java
+++ b/src/main/java/com/thealgorithms/searches/JumpSearch.java
@@ -2,44 +2,55 @@
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
 
+/**
+ * An implementation of the Jump Search algorithm.
+ *
+ * <p>
+ * Jump Search is an algorithm for searching sorted arrays. It works by dividing the array
+ * into blocks of a fixed size (the block size is typically the square root of the array length)
+ * and jumping ahead by this block size to find a range where the target element may be located.
+ * Once the range is found, a linear search is performed within that block.
+ *
+ * <p>
+ * The Jump Search algorithm is particularly effective for large sorted arrays where the cost of
+ * performing a linear search on the entire array would be prohibitive.
+ *
+ * <p>
+ * Worst-case performance: O(√N)<br>
+ * Best-case performance: O(1)<br>
+ * Average performance: O(√N)<br>
+ * Worst-case space complexity: O(1)
+ *
+ * <p>
+ * This class implements the {@link SearchAlgorithm} interface, providing a generic search method
+ * for any comparable type.
+ */
 public class JumpSearch implements SearchAlgorithm {
 
-    public static void main(String[] args) {
-        JumpSearch jumpSearch = new JumpSearch();
-        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
-        for (int i = 0; i < array.length; i++) {
-            assert jumpSearch.find(array, i) == i;
-        }
-        assert jumpSearch.find(array, -1) == -1;
-        assert jumpSearch.find(array, 11) == -1;
-    }
-
     /**
-     * Jump Search algorithm implements
+     * Jump Search algorithm implementation.
      *
-     * @param array the array contains elements
-     * @param key to be searched
-     * @return index of {@code key} if found, otherwise <tt>-1</tt>
+     * @param array the sorted array containing elements
+     * @param key   the element to be searched
+     * @return the index of {@code key} if found, otherwise -1
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
         int length = array.length;
-        /* length of array */
         int blockSize = (int) Math.sqrt(length);
-        /* block size to be jumped */
 
         int limit = blockSize;
-        while (key.compareTo(array[limit]) > 0 && limit < array.length - 1) {
-            limit = Math.min(limit + blockSize, array.length - 1);
+        // Jumping ahead to find the block where the key may be located
+        while (limit < length && key.compareTo(array[limit]) > 0) {
+            limit = Math.min(limit + blockSize, length - 1);
         }
 
-        for (int i = limit - blockSize; i <= limit; i++) {
-            if (array[i] == key) {
-                /* execute linear search */
+        // Perform linear search within the identified block
+        for (int i = limit - blockSize; i <= limit && i < length; i++) {
+            if (array[i].equals(key)) {
                 return i;
             }
         }
         return -1;
-        /* not found */
     }
 }
diff --git a/src/test/java/com/thealgorithms/searches/JumpSearchTest.java b/src/test/java/com/thealgorithms/searches/JumpSearchTest.java
new file mode 100644
index 000000000000..3fa319b66a41
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/JumpSearchTest.java
@@ -0,0 +1,94 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the JumpSearch class.
+ */
+class JumpSearchTest {
+
+    /**
+     * Test for finding an element present in the array.
+     */
+    @Test
+    void testJumpSearchFound() {
+        JumpSearch jumpSearch = new JumpSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 5; // Element to find
+        assertEquals(5, jumpSearch.find(array, key), "The index of the found element should be 5.");
+    }
+
+    /**
+     * Test for finding the first element in the array.
+     */
+    @Test
+    void testJumpSearchFirstElement() {
+        JumpSearch jumpSearch = new JumpSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 0; // First element
+        assertEquals(0, jumpSearch.find(array, key), "The index of the first element should be 0.");
+    }
+
+    /**
+     * Test for finding the last element in the array.
+     */
+    @Test
+    void testJumpSearchLastElement() {
+        JumpSearch jumpSearch = new JumpSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 10; // Last element
+        assertEquals(10, jumpSearch.find(array, key), "The index of the last element should be 10.");
+    }
+
+    /**
+     * Test for finding an element not present in the array.
+     */
+    @Test
+    void testJumpSearchNotFound() {
+        JumpSearch jumpSearch = new JumpSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = -1; // Element not in the array
+        assertEquals(-1, jumpSearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for finding an element in an empty array.
+     */
+    @Test
+    void testJumpSearchEmptyArray() {
+        JumpSearch jumpSearch = new JumpSearch();
+        Integer[] array = {}; // Empty array
+        Integer key = 1; // Key not present
+        assertEquals(-1, jumpSearch.find(array, key), "The element should not be found in an empty array.");
+    }
+
+    /**
+     * Test for finding an element in a large array.
+     */
+    @Test
+    void testJumpSearchLargeArray() {
+        JumpSearch jumpSearch = new JumpSearch();
+        Integer[] array = new Integer[1000];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = i * 2; // Fill the array with even numbers
+        }
+        Integer key = 256; // Present in the array
+        assertEquals(128, jumpSearch.find(array, key), "The index of the found element should be 128.");
+    }
+
+    /**
+     * Test for finding an element in a large array when it is not present.
+     */
+    @Test
+    void testJumpSearchLargeArrayNotFound() {
+        JumpSearch jumpSearch = new JumpSearch();
+        Integer[] array = new Integer[1000];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = i * 2; // Fill the array with even numbers
+        }
+        Integer key = 999; // Key not present
+        assertEquals(-1, jumpSearch.find(array, key), "The element should not be found in the array.");
+    }
+}

From a663e66782a1ceb3e7a82bffd1bd2ad41b42b13c Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:27:40 +0530
Subject: [PATCH 0498/1338] Add tests, remove `main` in
 `SquareRootBinarySearch` (#5676)

---
 DIRECTORY.md                                  |  1 +
 .../searches/SquareRootBinarySearch.java      | 18 +-----
 .../searches/SquareRootBinarySearchTest.java  | 57 +++++++++++++++++++
 3 files changed, 59 insertions(+), 17 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a22863e8b052..e272be8e2401 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1016,6 +1016,7 @@
             * [RecursiveBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java)
             * [RowColumnWiseSorted2dArrayBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java)
             * [SortOrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
+            * [SquareRootBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java)
             * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
           * sorts
             * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java b/src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java
index c00bfc9da6f5..95e062c274fd 100644
--- a/src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.searches;
 
-import java.util.Scanner;
-
 /**
  * Given an integer x, find the square root of x. If x is not a perfect square,
  * then return floor(√x).
@@ -18,20 +16,6 @@ public final class SquareRootBinarySearch {
     private SquareRootBinarySearch() {
     }
 
-    /**
-     * This is the driver method.
-     *
-     * @param args Command line arguments
-     */
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        System.out.print("Enter a number you want to calculate square root of : ");
-        int num = sc.nextInt();
-        long ans = squareRoot(num);
-        System.out.println("The square root is : " + ans);
-        sc.close();
-    }
-
     /**
      * This function calculates the floor of square root of a number. We use
      * Binary Search algorithm to calculate the square root in a more optimised
@@ -40,7 +24,7 @@ public static void main(String[] args) {
      * @param num Number
      * @return answer
      */
-    private static long squareRoot(long num) {
+    static long squareRoot(long num) {
         if (num == 0 || num == 1) {
             return num;
         }
diff --git a/src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java
new file mode 100644
index 000000000000..f23f4ee83fc3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java
@@ -0,0 +1,57 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class SquareRootBinarySearchTest {
+
+    @Test
+    void testPerfectSquare() {
+        long input = 16;
+        long expected = 4;
+        assertEquals(expected, SquareRootBinarySearch.squareRoot(input), "Square root of 16 should be 4");
+    }
+
+    @Test
+    void testNonPerfectSquare() {
+        long input = 15;
+        long expected = 3;
+        assertEquals(expected, SquareRootBinarySearch.squareRoot(input), "Square root of 15 should be 3");
+    }
+
+    @Test
+    void testZero() {
+        long input = 0;
+        long expected = 0;
+        assertEquals(expected, SquareRootBinarySearch.squareRoot(input), "Square root of 0 should be 0");
+    }
+
+    @Test
+    void testOne() {
+        long input = 1;
+        long expected = 1;
+        assertEquals(expected, SquareRootBinarySearch.squareRoot(input), "Square root of 1 should be 1");
+    }
+
+    @Test
+    void testLargeNumberPerfectSquare() {
+        long input = 1000000;
+        long expected = 1000;
+        assertEquals(expected, SquareRootBinarySearch.squareRoot(input), "Square root of 1000000 should be 1000");
+    }
+
+    @Test
+    void testLargeNumberNonPerfectSquare() {
+        long input = 999999;
+        long expected = 999;
+        assertEquals(expected, SquareRootBinarySearch.squareRoot(input), "Square root of 999999 should be 999");
+    }
+
+    @Test
+    void testNegativeInput() {
+        long input = -4;
+        long expected = 0; // Assuming the implementation should return 0 for negative input
+        assertEquals(expected, SquareRootBinarySearch.squareRoot(input), "Square root of negative number should return 0");
+    }
+}

From fb11d455ddfdebe071466d8adb6ec53c14aedd27 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:32:13 +0530
Subject: [PATCH 0499/1338] Add tests in `SearchInARowAndColWiseSortedMatrix`
 (#5675)

---
 DIRECTORY.md                                  |  1 +
 .../SearchInARowAndColWiseSortedMatrix.java   |  1 -
 ...earchInARowAndColWiseSortedMatrixTest.java | 66 +++++++++++++++++++
 3 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index e272be8e2401..18659ca229b3 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1015,6 +1015,7 @@
             * [RabinKarpAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java)
             * [RecursiveBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java)
             * [RowColumnWiseSorted2dArrayBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java)
+            * [SearchInARowAndColWiseSortedMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java)
             * [SortOrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
             * [SquareRootBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java)
             * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
diff --git a/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java b/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java
index 2bdcdb48b653..91fda373dca7 100644
--- a/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java
+++ b/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java
@@ -8,7 +8,6 @@ public class SearchInARowAndColWiseSortedMatrix {
      * @param value  Key being searched for
      * @author Sadiul Hakim : https://github.com/sadiul-hakim
      */
-
     public int[] search(int[][] matrix, int value) {
         int n = matrix.length;
         // This variable iterates over rows
diff --git a/src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java b/src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java
new file mode 100644
index 000000000000..88227804b775
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java
@@ -0,0 +1,66 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+class SearchInARowAndColWiseSortedMatrixTest {
+
+    private final SearchInARowAndColWiseSortedMatrix searcher = new SearchInARowAndColWiseSortedMatrix();
+
+    @Test
+    void testSearchValueExistsInMatrix() {
+        int[][] matrix = {{10, 20, 30, 40}, {15, 25, 35, 45}, {27, 29, 37, 48}, {32, 33, 39, 50}};
+        int value = 29;
+        int[] expected = {2, 1}; // Row 2, Column 1
+        assertArrayEquals(expected, searcher.search(matrix, value), "Value should be found in the matrix");
+    }
+
+    @Test
+    void testSearchValueNotExistsInMatrix() {
+        int[][] matrix = {{10, 20, 30, 40}, {15, 25, 35, 45}, {27, 29, 37, 48}, {32, 33, 39, 50}};
+        int value = 100;
+        int[] expected = {-1, -1}; // Not found
+        assertArrayEquals(expected, searcher.search(matrix, value), "Value should not be found in the matrix");
+    }
+
+    @Test
+    void testSearchInEmptyMatrix() {
+        int[][] matrix = {};
+        int value = 5;
+        int[] expected = {-1, -1}; // Not found
+        assertArrayEquals(expected, searcher.search(matrix, value), "Should return {-1, -1} for empty matrix");
+    }
+
+    @Test
+    void testSearchInSingleElementMatrixFound() {
+        int[][] matrix = {{5}};
+        int value = 5;
+        int[] expected = {0, 0}; // Found at (0,0)
+        assertArrayEquals(expected, searcher.search(matrix, value), "Value should be found in single element matrix");
+    }
+
+    @Test
+    void testSearchInSingleElementMatrixNotFound() {
+        int[][] matrix = {{10}};
+        int value = 5;
+        int[] expected = {-1, -1}; // Not found
+        assertArrayEquals(expected, searcher.search(matrix, value), "Should return {-1, -1} for value not found in single element matrix");
+    }
+
+    @Test
+    void testSearchInRowWiseSortedMatrix() {
+        int[][] matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+        int value = 6;
+        int[] expected = {1, 2}; // Found at (1, 2)
+        assertArrayEquals(expected, searcher.search(matrix, value), "Value should be found in the row-wise sorted matrix");
+    }
+
+    @Test
+    void testSearchInColWiseSortedMatrix() {
+        int[][] matrix = {{1, 4, 7}, {2, 5, 8}, {3, 6, 9}};
+        int value = 5;
+        int[] expected = {1, 1}; // Found at (1, 1)
+        assertArrayEquals(expected, searcher.search(matrix, value), "Value should be found in the column-wise sorted matrix");
+    }
+}

From 401d87365e3b073c6089d6089357515cd535cbec Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:37:02 +0530
Subject: [PATCH 0500/1338] Add tests, remove `main` in `UnionFind` (#5678)

---
 DIRECTORY.md                                  |  1 +
 .../com/thealgorithms/searches/UnionFind.java | 71 +++++++++-------
 .../thealgorithms/searches/UnionFindTest.java | 81 +++++++++++++++++++
 3 files changed, 126 insertions(+), 27 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/UnionFindTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 18659ca229b3..59b0ff5fa4a5 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1019,6 +1019,7 @@
             * [SortOrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
             * [SquareRootBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java)
             * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
+            * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java)
           * sorts
             * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
             * [BinaryInsertionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/UnionFind.java b/src/main/java/com/thealgorithms/searches/UnionFind.java
index 2effdf37bea5..01202a982266 100644
--- a/src/main/java/com/thealgorithms/searches/UnionFind.java
+++ b/src/main/java/com/thealgorithms/searches/UnionFind.java
@@ -4,11 +4,28 @@
 import java.util.Arrays;
 import java.util.List;
 
+/**
+ * The Union-Find data structure, also known as Disjoint Set Union (DSU),
+ * is a data structure that tracks a set of elements partitioned into
+ * disjoint (non-overlapping) subsets. It supports two main operations:
+ *
+ * 1. **Find**: Determine which subset a particular element is in.
+ * 2. **Union**: Join two subsets into a single subset.
+ *
+ * This implementation uses path compression in the `find` operation
+ * and union by rank in the `union` operation for efficiency.
+ */
 public class UnionFind {
 
-    private final int[] p;
-    private final int[] r;
+    private final int[] p; // Parent array
+    private final int[] r; // Rank array
 
+    /**
+     * Initializes a Union-Find data structure with n elements.
+     * Each element is its own parent initially.
+     *
+     * @param n the number of elements
+     */
     public UnionFind(int n) {
         p = new int[n];
         r = new int[n];
@@ -18,6 +35,13 @@ public UnionFind(int n) {
         }
     }
 
+    /**
+     * Finds the root of the set containing the element i.
+     * Uses path compression to flatten the structure.
+     *
+     * @param i the element to find
+     * @return the root of the set
+     */
     public int find(int i) {
         int parent = p[i];
 
@@ -25,12 +49,19 @@ public int find(int i) {
             return i;
         }
 
+        // Path compression
         final int result = find(parent);
         p[i] = result;
-
         return result;
     }
 
+    /**
+     * Unites the sets containing elements x and y.
+     * Uses union by rank to attach the smaller tree under the larger tree.
+     *
+     * @param x the first element
+     * @param y the second element
+     */
     public void union(int x, int y) {
         int r0 = find(x);
         int r1 = find(y);
@@ -39,6 +70,7 @@ public void union(int x, int y) {
             return;
         }
 
+        // Union by rank
         if (r[r0] > r[r1]) {
             p[r1] = r0;
         } else if (r[r1] > r[r0]) {
@@ -49,39 +81,24 @@ public void union(int x, int y) {
         }
     }
 
+    /**
+     * Counts the number of disjoint sets.
+     *
+     * @return the number of disjoint sets
+     */
     public int count() {
         List<Integer> parents = new ArrayList<>();
         for (int i = 0; i < p.length; i++) {
-            if (!parents.contains(find(i))) {
-                parents.add(find(i));
+            int root = find(i);
+            if (!parents.contains(root)) {
+                parents.add(root);
             }
         }
         return parents.size();
     }
 
+    @Override
     public String toString() {
         return "p " + Arrays.toString(p) + " r " + Arrays.toString(r) + "\n";
     }
-
-    // Tests
-    public static void main(String[] args) {
-        UnionFind uf = new UnionFind(5);
-        System.out.println("init /w 5 (should print 'p [0, 1, 2, 3, 4] r [0, 0, 0, 0, 0]'):");
-        System.out.println(uf);
-
-        uf.union(1, 2);
-        System.out.println("union 1 2 (should print 'p [0, 1, 1, 3, 4] r [0, 1, 0, 0, 0]'):");
-        System.out.println(uf);
-
-        uf.union(3, 4);
-        System.out.println("union 3 4 (should print 'p [0, 1, 1, 3, 3] r [0, 1, 0, 1, 0]'):");
-        System.out.println(uf);
-
-        uf.find(4);
-        System.out.println("find 4 (should print 'p [0, 1, 1, 3, 3] r [0, 1, 0, 1, 0]'):");
-        System.out.println(uf);
-
-        System.out.println("count (should print '3'):");
-        System.out.println(uf.count());
-    }
 }
diff --git a/src/test/java/com/thealgorithms/searches/UnionFindTest.java b/src/test/java/com/thealgorithms/searches/UnionFindTest.java
new file mode 100644
index 000000000000..3cc025ff595c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/UnionFindTest.java
@@ -0,0 +1,81 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class UnionFindTest {
+    private UnionFind uf;
+
+    @BeforeEach
+    void setUp() {
+        uf = new UnionFind(10); // Initialize with 10 elements
+    }
+
+    @Test
+    void testInitialState() {
+        // Verify that each element is its own parent and rank is 0
+        assertEquals("p [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] r [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]\n", uf.toString());
+        assertEquals(10, uf.count(), "Initial count of disjoint sets should be 10.");
+    }
+
+    @Test
+    void testUnionOperation() {
+        uf.union(0, 1);
+        uf.union(1, 2);
+        assertEquals(8, uf.count(), "Count should decrease after unions.");
+        assertEquals(0, uf.find(2), "Element 2 should point to root 0 after unions.");
+    }
+
+    @Test
+    void testUnionWithRank() {
+        uf.union(0, 1);
+        uf.union(1, 2); // Make 0 the root of 2
+        uf.union(3, 4);
+        uf.union(4, 5); // Make 3 the root of 5
+        uf.union(0, 3); // Union two trees
+
+        assertEquals(5, uf.count(), "Count should decrease after unions.");
+        assertEquals(0, uf.find(5), "Element 5 should point to root 0 after unions.");
+    }
+
+    @Test
+    void testFindOperation() {
+        uf.union(2, 3);
+        uf.union(4, 5);
+        uf.union(3, 5); // Connect 2-3 and 4-5
+
+        assertEquals(2, uf.find(3), "Find operation should return the root of the set.");
+        assertEquals(2, uf.find(5), "Find operation should return the root of the set.");
+    }
+
+    @Test
+    void testCountAfterMultipleUnions() {
+        uf.union(0, 1);
+        uf.union(2, 3);
+        uf.union(4, 5);
+        uf.union(1, 3); // Connect 0-1-2-3
+        uf.union(5, 6);
+
+        assertEquals(5, uf.count(), "Count should reflect the number of disjoint sets after multiple unions.");
+    }
+
+    @Test
+    void testNoUnion() {
+        assertEquals(10, uf.count(), "Count should remain 10 if no unions are made.");
+    }
+
+    @Test
+    void testUnionSameSet() {
+        uf.union(1, 2);
+        uf.union(1, 2); // Union same elements again
+
+        assertEquals(9, uf.count(), "Count should not decrease if union is called on the same set.");
+    }
+
+    @Test
+    void testFindOnSingleElement() {
+        assertEquals(7, uf.find(7), "Find on a single element should return itself.");
+    }
+}

From b1724fa73743014fe504fbe38d30dbe3fd30a4ce Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:42:07 +0530
Subject: [PATCH 0501/1338] Add tests, remove `main` in `LinearSearch` (#5670)

---
 DIRECTORY.md                                  |   1 +
 .../thealgorithms/searches/LinearSearch.java  |  18 ---
 .../searches/LinearSearchTest.java            | 118 ++++++++++++++++++
 3 files changed, 119 insertions(+), 18 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/LinearSearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 59b0ff5fa4a5..d0c62e600799 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1009,6 +1009,7 @@
             * [IterativeTernarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/IterativeTernarySearchTest.java)
             * [JumpSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/JumpSearchTest.java)
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
+            * [LinearSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/LinearSearchTest.java)
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
             * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
             * [QuickSelectTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/QuickSelectTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/LinearSearch.java b/src/main/java/com/thealgorithms/searches/LinearSearch.java
index 57927b30a632..c7b70edb5112 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearch.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearch.java
@@ -1,8 +1,6 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
-import java.util.Random;
-import java.util.stream.Stream;
 
 /**
  * Linear search is the easiest search algorithm It works with sorted and
@@ -36,20 +34,4 @@ public <T extends Comparable<T>> int find(T[] array, T value) {
         }
         return -1;
     }
-
-    public static void main(String[] args) {
-        // just generate data
-        Random r = new Random();
-        int size = 200;
-        int maxElement = 100;
-        Integer[] integers = Stream.generate(() -> r.nextInt(maxElement)).limit(size).toArray(Integer[] ::new);
-
-        // the element that should be found
-        Integer shouldBeFound = integers[r.nextInt(size - 1)];
-
-        LinearSearch search = new LinearSearch();
-        int atIndex = search.find(integers, shouldBeFound);
-
-        System.out.printf("Should be found: %d. Found %d at index %d. An array length %d%n", shouldBeFound, integers[atIndex], atIndex, size);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/searches/LinearSearchTest.java b/src/test/java/com/thealgorithms/searches/LinearSearchTest.java
new file mode 100644
index 000000000000..5c09dec6d578
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/LinearSearchTest.java
@@ -0,0 +1,118 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Random;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the LinearSearch class.
+ */
+class LinearSearchTest {
+
+    /**
+     * Test for finding an element present in the array.
+     */
+    @Test
+    void testLinearSearchFound() {
+        LinearSearch linearSearch = new LinearSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 5; // Element to find
+        assertEquals(5, linearSearch.find(array, key), "The index of the found element should be 5.");
+    }
+
+    /**
+     * Test for finding the first element in the array.
+     */
+    @Test
+    void testLinearSearchFirstElement() {
+        LinearSearch linearSearch = new LinearSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 0; // First element
+        assertEquals(0, linearSearch.find(array, key), "The index of the first element should be 0.");
+    }
+
+    /**
+     * Test for finding the last element in the array.
+     */
+    @Test
+    void testLinearSearchLastElement() {
+        LinearSearch linearSearch = new LinearSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 10; // Last element
+        assertEquals(10, linearSearch.find(array, key), "The index of the last element should be 10.");
+    }
+
+    /**
+     * Test for finding an element not present in the array.
+     */
+    @Test
+    void testLinearSearchNotFound() {
+        LinearSearch linearSearch = new LinearSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = -1; // Element not in the array
+        assertEquals(-1, linearSearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for finding an element in an empty array.
+     */
+    @Test
+    void testLinearSearchEmptyArray() {
+        LinearSearch linearSearch = new LinearSearch();
+        Integer[] array = {}; // Empty array
+        Integer key = 1; // Key not present
+        assertEquals(-1, linearSearch.find(array, key), "The element should not be found in an empty array.");
+    }
+
+    /**
+     * Test for finding an element in a large array.
+     */
+    @Test
+    void testLinearSearchLargeArray() {
+        LinearSearch linearSearch = new LinearSearch();
+        Integer[] array = new Integer[1000];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = i; // Fill the array with integers 0 to 999
+        }
+        Integer key = 256; // Present in the array
+        assertEquals(256, linearSearch.find(array, key), "The index of the found element should be 256.");
+    }
+
+    /**
+     * Test for finding an element in a large array when it is not present.
+     */
+    @Test
+    void testLinearSearchLargeArrayNotFound() {
+        LinearSearch linearSearch = new LinearSearch();
+        Integer[] array = new Integer[1000];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = i; // Fill the array with integers 0 to 999
+        }
+        Integer key = 1001; // Key not present
+        assertEquals(-1, linearSearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for finding multiple occurrences of the same element in the array.
+     */
+    @Test
+    void testLinearSearchMultipleOccurrences() {
+        LinearSearch linearSearch = new LinearSearch();
+        Integer[] array = {1, 2, 3, 4, 5, 3, 6, 7, 3}; // 3 occurs multiple times
+        Integer key = 3; // Key to find
+        assertEquals(2, linearSearch.find(array, key), "The index of the first occurrence of the element should be 2.");
+    }
+
+    /**
+     * Test for performance with random large array.
+     */
+    @Test
+    void testLinearSearchRandomArray() {
+        LinearSearch linearSearch = new LinearSearch();
+        Random random = new Random();
+        Integer[] array = random.ints(0, 1000).distinct().limit(1000).boxed().toArray(Integer[] ::new);
+        Integer key = array[random.nextInt(array.length)]; // Key should be in the array
+        assertEquals(java.util.Arrays.asList(array).indexOf(key), linearSearch.find(array, key), "The index of the found element should match.");
+    }
+}

From e8b32513c8871c1530908d66648aabb882b32ca0 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:50:39 +0530
Subject: [PATCH 0502/1338] Add tests, remove `main` in `MonteCarloTreeSearch`
 (#5673)

---
 DIRECTORY.md                                  |   1 +
 .../searches/MonteCarloTreeSearch.java        |   6 -
 .../searches/MonteCarloTreeSearchTest.java    | 126 ++++++++++++++++++
 3 files changed, 127 insertions(+), 6 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/MonteCarloTreeSearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index d0c62e600799..cfc8841fbcbe 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1010,6 +1010,7 @@
             * [JumpSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/JumpSearchTest.java)
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
             * [LinearSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/LinearSearchTest.java)
+            * [MonteCarloTreeSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/MonteCarloTreeSearchTest.java)
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
             * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
             * [QuickSelectTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/QuickSelectTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java b/src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java
index 268c33cef610..aa74398b708b 100644
--- a/src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java
+++ b/src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java
@@ -39,12 +39,6 @@ public Node(Node parent, boolean isPlayersTurn) {
     static final int WIN_SCORE = 10;
     static final int TIME_LIMIT = 500; // Time the algorithm will be running for (in milliseconds).
 
-    public static void main(String[] args) {
-        MonteCarloTreeSearch mcts = new MonteCarloTreeSearch();
-
-        mcts.monteCarloTreeSearch(mcts.new Node(null, true));
-    }
-
     /**
      * Explores a game tree using Monte Carlo Tree Search (MCTS) and returns the
      * most promising node.
diff --git a/src/test/java/com/thealgorithms/searches/MonteCarloTreeSearchTest.java b/src/test/java/com/thealgorithms/searches/MonteCarloTreeSearchTest.java
new file mode 100644
index 000000000000..69c958f67a40
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/MonteCarloTreeSearchTest.java
@@ -0,0 +1,126 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class MonteCarloTreeSearchTest {
+
+    /**
+     * Test the creation of a node and its initial state.
+     */
+    @Test
+    void testNodeCreation() {
+        MonteCarloTreeSearch.Node node = new MonteCarloTreeSearch().new Node(null, true);
+        assertNotNull(node, "Node should be created");
+        assertTrue(node.childNodes.isEmpty(), "Child nodes should be empty upon creation");
+        assertTrue(node.isPlayersTurn, "Initial turn should be player's turn");
+        assertEquals(0, node.score, "Initial score should be zero");
+        assertEquals(0, node.visitCount, "Initial visit count should be zero");
+    }
+
+    /**
+     * Test adding child nodes to a parent node.
+     */
+    @Test
+    void testAddChildNodes() {
+        MonteCarloTreeSearch mcts = new MonteCarloTreeSearch();
+        MonteCarloTreeSearch.Node parentNode = mcts.new Node(null, true);
+
+        mcts.addChildNodes(parentNode, 5);
+
+        assertEquals(5, parentNode.childNodes.size(), "Parent should have 5 child nodes");
+        for (MonteCarloTreeSearch.Node child : parentNode.childNodes) {
+            assertFalse(child.isPlayersTurn, "Child node should not be player's turn");
+            assertEquals(0, child.visitCount, "Child node visit count should be zero");
+        }
+    }
+
+    /**
+     * Test the UCT selection of a promising node.
+     */
+    @Test
+    void testGetPromisingNode() {
+        MonteCarloTreeSearch mcts = new MonteCarloTreeSearch();
+        MonteCarloTreeSearch.Node parentNode = mcts.new Node(null, true);
+
+        // Create child nodes with different visit counts and scores
+        for (int i = 0; i < 3; i++) {
+            MonteCarloTreeSearch.Node child = mcts.new Node(parentNode, false);
+            child.visitCount = i + 1;
+            child.score = i * 2;
+            parentNode.childNodes.add(child);
+        }
+
+        // Get promising node
+        MonteCarloTreeSearch.Node promisingNode = mcts.getPromisingNode(parentNode);
+
+        // The child with the highest UCT value should be chosen.
+        assertNotNull(promisingNode, "Promising node should not be null");
+        assertEquals(0, parentNode.childNodes.indexOf(promisingNode), "The first child should be the most promising");
+    }
+
+    /**
+     * Test simulation of random play and backpropagation.
+     */
+    @Test
+    void testSimulateRandomPlay() {
+        MonteCarloTreeSearch mcts = new MonteCarloTreeSearch();
+        MonteCarloTreeSearch.Node node = mcts.new Node(null, true);
+        node.visitCount = 10; // Simulating existing visits
+
+        // Simulate random play
+        mcts.simulateRandomPlay(node);
+
+        // Check visit count after simulation
+        assertEquals(11, node.visitCount, "Visit count should increase after simulation");
+
+        // Check if score is updated correctly
+        assertTrue(node.score >= 0 && node.score <= MonteCarloTreeSearch.WIN_SCORE, "Score should be between 0 and WIN_SCORE");
+    }
+
+    /**
+     * Test retrieving the winning node based on scores.
+     */
+    @Test
+    void testGetWinnerNode() {
+        MonteCarloTreeSearch mcts = new MonteCarloTreeSearch();
+        MonteCarloTreeSearch.Node parentNode = mcts.new Node(null, true);
+
+        // Create child nodes with varying scores
+        MonteCarloTreeSearch.Node winningNode = mcts.new Node(parentNode, false);
+        winningNode.score = 10; // Highest score
+        parentNode.childNodes.add(winningNode);
+
+        MonteCarloTreeSearch.Node losingNode = mcts.new Node(parentNode, false);
+        losingNode.score = 5;
+        parentNode.childNodes.add(losingNode);
+
+        MonteCarloTreeSearch.Node anotherLosingNode = mcts.new Node(parentNode, false);
+        anotherLosingNode.score = 3;
+        parentNode.childNodes.add(anotherLosingNode);
+
+        // Get the winning node
+        MonteCarloTreeSearch.Node winnerNode = mcts.getWinnerNode(parentNode);
+
+        assertEquals(winningNode, winnerNode, "Winning node should have the highest score");
+    }
+
+    /**
+     * Test the full Monte Carlo Tree Search process.
+     */
+    @Test
+    void testMonteCarloTreeSearch() {
+        MonteCarloTreeSearch mcts = new MonteCarloTreeSearch();
+        MonteCarloTreeSearch.Node rootNode = mcts.new Node(null, true);
+
+        // Execute MCTS and check the resulting node
+        MonteCarloTreeSearch.Node optimalNode = mcts.monteCarloTreeSearch(rootNode);
+
+        assertNotNull(optimalNode, "MCTS should return a non-null optimal node");
+        assertTrue(rootNode.childNodes.contains(optimalNode), "Optimal node should be a child of the root");
+    }
+}

From 29ad197a64f1403e27344616f8b594147d949aa9 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:54:52 +0530
Subject: [PATCH 0503/1338] Add tests, remove `main` in `SaddlebackSearch`
 (#5674)

---
 DIRECTORY.md                                  |  1 +
 .../searches/SaddlebackSearch.java            | 35 ++------
 .../searches/SaddlebackSearchTest.java        | 85 +++++++++++++++++++
 3 files changed, 92 insertions(+), 29 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/SaddlebackSearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index cfc8841fbcbe..cbe176f27440 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1017,6 +1017,7 @@
             * [RabinKarpAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java)
             * [RecursiveBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java)
             * [RowColumnWiseSorted2dArrayBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java)
+            * [SaddlebackSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SaddlebackSearchTest.java)
             * [SearchInARowAndColWiseSortedMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java)
             * [SortOrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
             * [SquareRootBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java b/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java
index 5c7a914e3bf2..192c4d26c735 100644
--- a/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java
+++ b/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.searches;
 
-import java.util.Scanner;
-
 /**
  * Program to perform Saddleback Search Given a sorted 2D array(elements are
  * sorted across every row and column, assuming ascending order) of size n*m we
@@ -27,10 +25,15 @@ private SaddlebackSearch() {
      * @param row the current row.
      * @param col the current column.
      * @param key the element that we want to search for.
+     * @throws IllegalArgumentException if the array is empty.
      * @return The index(row and column) of the element if found. Else returns
      * -1 -1.
      */
-    private static int[] find(int[][] arr, int row, int col, int key) {
+    static int[] find(int[][] arr, int row, int col, int key) {
+        if (arr.length == 0) {
+            throw new IllegalArgumentException("Array is empty");
+        }
+
         // array to store the answer row and column
         int[] ans = {-1, -1};
         if (row < 0 || col >= arr[row].length) {
@@ -47,30 +50,4 @@ else if (arr[row][col] > key) {
         // else we move right
         return find(arr, row, col + 1, key);
     }
-
-    /**
-     * Main method
-     *
-     * @param args Command line arguments
-     */
-    public static void main(String[] args) {
-        // TODO Auto-generated method stub
-        Scanner sc = new Scanner(System.in);
-        int[][] arr;
-        int i;
-        int j;
-        int rows = sc.nextInt();
-        int col = sc.nextInt();
-        arr = new int[rows][col];
-        for (i = 0; i < rows; i++) {
-            for (j = 0; j < col; j++) {
-                arr[i][j] = sc.nextInt();
-            }
-        }
-        int ele = sc.nextInt();
-        // we start from bottom left corner
-        int[] ans = find(arr, rows - 1, 0, ele);
-        System.out.println(ans[0] + " " + ans[1]);
-        sc.close();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/searches/SaddlebackSearchTest.java b/src/test/java/com/thealgorithms/searches/SaddlebackSearchTest.java
new file mode 100644
index 000000000000..ec22cbf38152
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/SaddlebackSearchTest.java
@@ -0,0 +1,85 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class SaddlebackSearchTest {
+
+    /**
+     * Test searching for an element that exists in the array.
+     */
+    @Test
+    void testFindElementExists() {
+        int[][] arr = {{-10, -5, -3, 4, 9}, {-6, -2, 0, 5, 10}, {-4, -1, 1, 6, 12}, {2, 3, 7, 8, 13}, {100, 120, 130, 140, 150}};
+
+        int[] result = SaddlebackSearch.find(arr, arr.length - 1, 0, 4);
+        assertArrayEquals(new int[] {0, 3}, result, "Element 4 should be found at (0, 3)");
+    }
+
+    /**
+     * Test searching for an element that does not exist in the array.
+     */
+    @Test
+    void testFindElementNotExists() {
+        int[][] arr = {{-10, -5, -3, 4, 9}, {-6, -2, 0, 5, 10}, {-4, -1, 1, 6, 12}, {2, 3, 7, 8, 13}, {100, 120, 130, 140, 150}};
+
+        int[] result = SaddlebackSearch.find(arr, arr.length - 1, 0, 1000);
+        assertArrayEquals(new int[] {-1, -1}, result, "Element 1000 should not be found");
+    }
+
+    /**
+     * Test searching for the smallest element in the array.
+     */
+    @Test
+    void testFindSmallestElement() {
+        int[][] arr = {{-10, -5, -3, 4, 9}, {-6, -2, 0, 5, 10}, {-4, -1, 1, 6, 12}, {2, 3, 7, 8, 13}, {100, 120, 130, 140, 150}};
+
+        int[] result = SaddlebackSearch.find(arr, arr.length - 1, 0, -10);
+        assertArrayEquals(new int[] {0, 0}, result, "Element -10 should be found at (0, 0)");
+    }
+
+    /**
+     * Test searching for the largest element in the array.
+     */
+    @Test
+    void testFindLargestElement() {
+        int[][] arr = {{-10, -5, -3, 4, 9}, {-6, -2, 0, 5, 10}, {-4, -1, 1, 6, 12}, {2, 3, 7, 8, 13}, {100, 120, 130, 140, 150}};
+
+        int[] result = SaddlebackSearch.find(arr, arr.length - 1, 0, 150);
+        assertArrayEquals(new int[] {4, 4}, result, "Element 150 should be found at (4, 4)");
+    }
+
+    /**
+     * Test searching in an empty array.
+     */
+    @Test
+    void testFindInEmptyArray() {
+        int[][] arr = {};
+
+        assertThrows(IllegalArgumentException.class, () -> { SaddlebackSearch.find(arr, 0, 0, 4); });
+    }
+
+    /**
+     * Test searching in a single element array that matches the search key.
+     */
+    @Test
+    void testFindSingleElementExists() {
+        int[][] arr = {{5}};
+
+        int[] result = SaddlebackSearch.find(arr, 0, 0, 5);
+        assertArrayEquals(new int[] {0, 0}, result, "Element 5 should be found at (0, 0)");
+    }
+
+    /**
+     * Test searching in a single element array that does not match the search key.
+     */
+    @Test
+    void testFindSingleElementNotExists() {
+        int[][] arr = {{5}};
+
+        int[] result = SaddlebackSearch.find(arr, 0, 0, 10);
+        assertArrayEquals(new int[] {-1, -1}, result, "Element 10 should not be found in single element array");
+    }
+}

From 680202925192bbf6b5024aef9f0a0cba959e3315 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 01:59:20 +0530
Subject: [PATCH 0504/1338] Add tests, remove `main` in `LinearSearchThread`
 (#5671)

---
 DIRECTORY.md                                  |  1 +
 .../searches/LinearSearchThread.java          | 83 ++++++++++---------
 .../searches/LinearSearchThreadTest.java      | 74 +++++++++++++++++
 3 files changed, 118 insertions(+), 40 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index cbe176f27440..f0c4486eebe6 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1010,6 +1010,7 @@
             * [JumpSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/JumpSearchTest.java)
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
             * [LinearSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/LinearSearchTest.java)
+            * [LinearSearchThreadTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java)
             * [MonteCarloTreeSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/MonteCarloTreeSearchTest.java)
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
             * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/LinearSearchThread.java b/src/main/java/com/thealgorithms/searches/LinearSearchThread.java
index b354d312d1b3..ba3cff915f5f 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearchThread.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearchThread.java
@@ -1,52 +1,47 @@
 package com.thealgorithms.searches;
 
-import java.util.Scanner;
-
+/**
+ * LinearSearchThread is a multithreaded implementation of the linear search algorithm.
+ * It creates multiple threads to search for a specific number in an array.
+ *
+ * <p>
+ * The class generates an array of random integers, prompts the user to enter a number to search for,
+ * and divides the array into four segments, each handled by a separate thread.
+ * The threads run concurrently and search for the specified number within their designated segments.
+ * Finally, it consolidates the results to determine if the number was found.
+ * </p>
+ *
+ * <p>
+ * Example usage:
+ * 1. The program will output the generated array.
+ * 2. The user will be prompted to input a number to search for.
+ * 3. The program will display whether the number was found in the array.
+ * </p>
+ */
 public final class LinearSearchThread {
     private LinearSearchThread() {
     }
-
-    public static void main(String[] args) {
-        int[] list = new int[200];
-        for (int j = 0; j < list.length; j++) {
-            list[j] = (int) (Math.random() * 100);
-        }
-        for (int y : list) {
-            System.out.print(y + " ");
-        }
-        System.out.println();
-        System.out.print("Enter number to search for: ");
-        Scanner in = new Scanner(System.in);
-        int x = in.nextInt();
-        Searcher t = new Searcher(list, 0, 50, x);
-        Searcher t1 = new Searcher(list, 50, 100, x);
-        Searcher t2 = new Searcher(list, 100, 150, x);
-        Searcher t3 = new Searcher(list, 150, 200, x);
-        t.start();
-        t1.start();
-        t2.start();
-        t3.start();
-        try {
-            t.join();
-            t1.join();
-            t2.join();
-            t3.join();
-        } catch (InterruptedException e) {
-        }
-        boolean found = t.getResult() || t1.getResult() || t2.getResult() || t3.getResult();
-        System.out.println("Found = " + found);
-        in.close();
-    }
 }
 
+/**
+ * The Searcher class extends Thread and is responsible for searching for a specific
+ * number in a segment of an array.
+ */
 class Searcher extends Thread {
+    private final int[] arr; // The array to search in
+    private final int left; // Starting index of the segment
+    private final int right; // Ending index of the segment
+    private final int x; // The number to search for
+    private boolean found; // Result flag
 
-    private final int[] arr;
-    private final int left;
-    private final int right;
-    private final int x;
-    private boolean found;
-
+    /**
+     * Constructor to initialize the Searcher.
+     *
+     * @param arr The array to search in
+     * @param left The starting index of the segment
+     * @param right The ending index of the segment
+     * @param x The number to search for
+     */
     Searcher(int[] arr, int left, int right, int x) {
         this.arr = arr;
         this.left = left;
@@ -54,6 +49,9 @@ class Searcher extends Thread {
         this.x = x;
     }
 
+    /**
+     * The run method for the thread, performing the linear search in its segment.
+     */
     @Override
     public void run() {
         int k = left;
@@ -65,6 +63,11 @@ public void run() {
         }
     }
 
+    /**
+     * Returns whether the number was found in the segment.
+     *
+     * @return true if the number was found, false otherwise
+     */
     boolean getResult() {
         return found;
     }
diff --git a/src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java b/src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java
new file mode 100644
index 000000000000..534c2a4487b2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java
@@ -0,0 +1,74 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class LinearSearchThreadTest {
+
+    /**
+     * Test for finding an element that is present in the array.
+     */
+    @Test
+    void testSearcherFound() throws InterruptedException {
+        int[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Searcher searcher = new Searcher(array, 0, array.length, 5);
+        searcher.start();
+        searcher.join();
+        assertTrue(searcher.getResult(), "The element 5 should be found in the array.");
+    }
+
+    /**
+     * Test for finding an element that is not present in the array.
+     */
+    @Test
+    void testSearcherNotFound() throws InterruptedException {
+        int[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Searcher searcher = new Searcher(array, 0, array.length, 11);
+        searcher.start();
+        searcher.join();
+        assertFalse(searcher.getResult(), "The element 11 should not be found in the array.");
+    }
+
+    /**
+     * Test for searching a segment of the array.
+     */
+    @Test
+    void testSearcherSegmentFound() throws InterruptedException {
+        int[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Searcher searcher = new Searcher(array, 0, 5, 3);
+        searcher.start();
+        searcher.join();
+        assertTrue(searcher.getResult(), "The element 3 should be found in the segment.");
+    }
+
+    /**
+     * Test for searching an empty array segment.
+     */
+    @Test
+    void testSearcherEmptySegment() throws InterruptedException {
+        int[] array = {};
+        Searcher searcher = new Searcher(array, 0, 0, 1); // Empty array
+        searcher.start();
+        searcher.join();
+        assertFalse(searcher.getResult(), "The element should not be found in an empty segment.");
+    }
+
+    /**
+     * Test for searching with random numbers.
+     */
+    @Test
+    void testSearcherRandomNumbers() throws InterruptedException {
+        int size = 200;
+        int[] array = new int[size];
+        for (int i = 0; i < size; i++) {
+            array[i] = (int) (Math.random() * 100);
+        }
+        int target = array[(int) (Math.random() * size)]; // Randomly select a target that is present
+        Searcher searcher = new Searcher(array, 0, size, target);
+        searcher.start();
+        searcher.join();
+        assertTrue(searcher.getResult(), "The randomly selected target should be found in the array.");
+    }
+}

From 4ec270130286146cfc9e9e02993580d484fce26a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 02:02:32 +0530
Subject: [PATCH 0505/1338] Add tests, remove `main` in `TernarySearch` (#5677)

---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/searches/TernarySearch.java | 22 -----
 .../searches/TernarySearchTest.java           | 81 +++++++++++++++++++
 3 files changed, 82 insertions(+), 22 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/TernarySearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index f0c4486eebe6..3863f62c507b 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1022,6 +1022,7 @@
             * [SearchInARowAndColWiseSortedMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java)
             * [SortOrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
             * [SquareRootBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java)
+            * [TernarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TernarySearchTest.java)
             * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
             * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java)
           * sorts
diff --git a/src/main/java/com/thealgorithms/searches/TernarySearch.java b/src/main/java/com/thealgorithms/searches/TernarySearch.java
index 3395bc0b7f30..4d9f55ea9917 100644
--- a/src/main/java/com/thealgorithms/searches/TernarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/TernarySearch.java
@@ -1,9 +1,6 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
-import java.util.Arrays;
-import java.util.Random;
-import java.util.stream.Stream;
 
 /**
  * A ternary search algorithm is a technique in computer science for finding the
@@ -60,23 +57,4 @@ private <T extends Comparable<T>> int ternarySearch(T[] arr, T key, int start, i
             return ternarySearch(arr, key, mid1, mid2);
         }
     }
-
-    public static void main(String[] args) {
-        // just generate data
-        Random r = new Random();
-        int size = 100;
-        int maxElement = 100000;
-        Integer[] integers = Stream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().toArray(Integer[] ::new);
-
-        // the element that should be found
-        Integer shouldBeFound = integers[r.nextInt(size - 1)];
-
-        TernarySearch search = new TernarySearch();
-        int atIndex = search.find(integers, shouldBeFound);
-
-        System.out.printf("Should be found: %d. Found %d at index %d. An array length %d%n", shouldBeFound, integers[atIndex], atIndex, size);
-
-        int toCheck = Arrays.binarySearch(integers, shouldBeFound);
-        System.out.printf("Found by system method at an index: %d. Is equal: %b%n", toCheck, toCheck == atIndex);
-    }
 }
diff --git a/src/test/java/com/thealgorithms/searches/TernarySearchTest.java b/src/test/java/com/thealgorithms/searches/TernarySearchTest.java
new file mode 100644
index 000000000000..367b595e55d9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/TernarySearchTest.java
@@ -0,0 +1,81 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class TernarySearchTest {
+
+    @Test
+    void testFindElementInSortedArray() {
+        Integer[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 5);
+
+        assertEquals(4, index, "Should find the element 5 at index 4");
+    }
+
+    @Test
+    void testElementNotFound() {
+        Integer[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 11);
+
+        assertEquals(-1, index, "Should return -1 for element 11 which is not present");
+    }
+
+    @Test
+    void testFindFirstElement() {
+        Integer[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 1);
+
+        assertEquals(0, index, "Should find the first element 1 at index 0");
+    }
+
+    @Test
+    void testFindLastElement() {
+        Integer[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 10);
+
+        assertEquals(9, index, "Should find the last element 10 at index 9");
+    }
+
+    @Test
+    void testFindInLargeArray() {
+        Integer[] arr = new Integer[1000];
+        for (int i = 0; i < 1000; i++) {
+            arr[i] = i + 1; // Array from 1 to 1000
+        }
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 500);
+
+        assertEquals(499, index, "Should find element 500 at index 499");
+    }
+
+    @Test
+    void testNegativeNumbers() {
+        Integer[] arr = {-10, -5, -3, -1, 0, 1, 3, 5, 7, 10};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, -3);
+
+        assertEquals(2, index, "Should find the element -3 at index 2");
+    }
+
+    @Test
+    void testEdgeCaseEmptyArray() {
+        Integer[] arr = {};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 5);
+
+        assertEquals(-1, index, "Should return -1 for an empty array");
+    }
+}

From b1aeac5cd68c3cafc56739f8a021587c8f3e33d7 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 02:06:06 +0530
Subject: [PATCH 0506/1338] Add tests, remove `main` in `UpperBound` (#5679)

---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/searches/UpperBound.java    | 25 -----
 .../searches/UpperBoundTest.java              | 99 +++++++++++++++++++
 3 files changed, 100 insertions(+), 25 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/UpperBoundTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 3863f62c507b..7ebc176b02cf 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1025,6 +1025,7 @@
             * [TernarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TernarySearchTest.java)
             * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
             * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java)
+            * [UpperBoundTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UpperBoundTest.java)
           * sorts
             * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
             * [BinaryInsertionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/UpperBound.java b/src/main/java/com/thealgorithms/searches/UpperBound.java
index bbce617a143b..ec52c7a0ae5c 100644
--- a/src/main/java/com/thealgorithms/searches/UpperBound.java
+++ b/src/main/java/com/thealgorithms/searches/UpperBound.java
@@ -1,9 +1,6 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
-import java.util.Random;
-import java.util.concurrent.ThreadLocalRandom;
-import java.util.stream.IntStream;
 
 /**
  * The UpperBound method is used to return an index pointing to the first
@@ -25,28 +22,6 @@
  */
 class UpperBound implements SearchAlgorithm {
 
-    // Driver Program
-    public static void main(String[] args) {
-        // Just generate data
-        Random r = ThreadLocalRandom.current();
-
-        int size = 100;
-        int maxElement = 100000;
-
-        Integer[] integers = IntStream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().boxed().toArray(Integer[] ::new);
-
-        // The element for which the upper bound is to be found
-        int val = integers[r.nextInt(size - 1)] + 1;
-
-        UpperBound search = new UpperBound();
-        int atIndex = search.find(integers, val);
-
-        System.out.printf("Val: %d. Upper Bound Found %d at index %d. An array length %d%n", val, integers[atIndex], atIndex, size);
-
-        boolean toCheck = integers[atIndex] > val || integers[size - 1] < val;
-        System.out.printf("Upper Bound found at an index: %d. Is greater or max element: %b%n", atIndex, toCheck);
-    }
-
     /**
      * @param array is an array where the UpperBound value is to be found
      * @param key is an element for which the UpperBound is to be found
diff --git a/src/test/java/com/thealgorithms/searches/UpperBoundTest.java b/src/test/java/com/thealgorithms/searches/UpperBoundTest.java
new file mode 100644
index 000000000000..dc0cbdd97e19
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/UpperBoundTest.java
@@ -0,0 +1,99 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Random;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class UpperBoundTest {
+
+    private UpperBound upperBound;
+    private Integer[] sortedArray;
+
+    @BeforeEach
+    void setUp() {
+        upperBound = new UpperBound();
+
+        // Generate a sorted array of random integers for testing
+        Random random = new Random();
+        int size = 100;
+        int maxElement = 100;
+        sortedArray = random.ints(size, 1, maxElement)
+                          .distinct() // Ensure all elements are unique
+                          .sorted()
+                          .boxed()
+                          .toArray(Integer[] ::new);
+    }
+
+    @Test
+    void testUpperBoundFound() {
+        int key = sortedArray[sortedArray.length - 1] + 1; // Test with a key larger than max element
+        int index = upperBound.find(sortedArray, key);
+
+        // The upper bound should be equal to the length of the array
+        assertEquals(sortedArray.length - 1, index, "Upper bound for a larger key should be the size of the array.");
+    }
+
+    @Test
+    void testUpperBoundExactMatch() {
+        int key = sortedArray[sortedArray.length / 2]; // Choose a key from the middle of the array
+        int index = upperBound.find(sortedArray, key);
+
+        // The index should point to the first element greater than the key
+        assertTrue(index < sortedArray.length, "Upper bound should not exceed array length.");
+        assertTrue(sortedArray[index] > key, "The element at the index should be greater than the key.");
+    }
+
+    @Test
+    void testUpperBoundMultipleValues() {
+        Integer[] arrayWithDuplicates = new Integer[] {1, 1, 2, 3, 4, 4, 5, 6, 7, 8, 9}; // Test array with duplicates
+        int key = 4;
+        int index = upperBound.find(arrayWithDuplicates, key);
+
+        assertTrue(index < arrayWithDuplicates.length, "Upper bound index should be valid.");
+        assertEquals(6, index, "The upper bound for 4 should be the index of the first 5.");
+        assertTrue(arrayWithDuplicates[index] > key, "Element at the upper bound index should be greater than the key.");
+    }
+
+    @Test
+    void testUpperBoundLowerThanMin() {
+        int key = 0; // Test with a key lower than the minimum element
+        int index = upperBound.find(sortedArray, key);
+
+        assertEquals(0, index, "Upper bound for a key lower than minimum should be 0.");
+        assertTrue(sortedArray[index] > key, "The element at index 0 should be greater than the key.");
+    }
+
+    @Test
+    void testUpperBoundHigherThanMax() {
+        int key = sortedArray[sortedArray.length - 1] + 1; // Test with a key higher than maximum element
+        int index = upperBound.find(sortedArray, key);
+
+        assertEquals(sortedArray.length - 1, index, "Upper bound for a key higher than maximum should be the size of the array.");
+    }
+
+    @Test
+    void testUpperBoundEdgeCase() {
+        // Edge case: empty array
+        Integer[] emptyArray = {};
+        int index = upperBound.find(emptyArray, 5);
+
+        assertEquals(0, index, "Upper bound for an empty array should be 0.");
+    }
+
+    @Test
+    void testUpperBoundSingleElementArray() {
+        Integer[] singleElementArray = {10};
+        int index = upperBound.find(singleElementArray, 5);
+
+        assertEquals(0, index, "Upper bound for 5 in a single element array should be 0.");
+
+        index = upperBound.find(singleElementArray, 10);
+        assertEquals(0, index, "Upper bound for 10 in a single element array should be 0.");
+
+        index = upperBound.find(singleElementArray, 15);
+        assertEquals(0, index, "Upper bound for 15 in a single element array should be 0.");
+    }
+}

From 79544c81eb5525ebc0e5a930c897d6d2e141481e Mon Sep 17 00:00:00 2001
From: Saahil Mahato <115351000+saahil-mahato@users.noreply.github.com>
Date: Fri, 11 Oct 2024 02:26:58 +0545
Subject: [PATCH 0507/1338] feat: add solovay strassen primality test (#5692)

* feat: add solovay strassen primality test

* chore: add wikipedia link

* fix: format and coverage

* fix: mvn stylecheck

* fix: PMD errors

* refactor: make random final

---------

Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 .../maths/SolovayStrassenPrimalityTest.java   | 133 ++++++++++++++++++
 .../SolovayStrassenPrimalityTestTest.java     | 122 ++++++++++++++++
 2 files changed, 255 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java
 create mode 100644 src/test/java/com/thealgorithms/maths/SolovayStrassenPrimalityTestTest.java

diff --git a/src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java b/src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java
new file mode 100644
index 000000000000..caa1abfc3203
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java
@@ -0,0 +1,133 @@
+package com.thealgorithms.maths;
+
+import java.util.Random;
+
+/**
+ * This class implements the Solovay-Strassen primality test,
+ * which is a probabilistic algorithm to determine whether a number is prime.
+ * The algorithm is based on properties of the Jacobi symbol and modular exponentiation.
+ *
+ * For more information, go to {@link https://en.wikipedia.org/wiki/Solovay%E2%80%93Strassen_primality_test}
+ */
+final class SolovayStrassenPrimalityTest {
+
+    private final Random random;
+
+    /**
+     * Constructs a SolovayStrassenPrimalityTest instance with a specified seed for randomness.
+     *
+     * @param seed the seed for generating random numbers
+     */
+    private SolovayStrassenPrimalityTest(int seed) {
+        random = new Random(seed);
+    }
+
+    /**
+     * Factory method to create an instance of SolovayStrassenPrimalityTest.
+     *
+     * @param seed the seed for generating random numbers
+     * @return a new instance of SolovayStrassenPrimalityTest
+     */
+    public static SolovayStrassenPrimalityTest getSolovayStrassenPrimalityTest(int seed) {
+        return new SolovayStrassenPrimalityTest(seed);
+    }
+
+    /**
+     * Calculates modular exponentiation using the method of exponentiation by squaring.
+     *
+     * @param base the base number
+     * @param exponent the exponent
+     * @param mod the modulus
+     * @return (base^exponent) mod mod
+     */
+    private static long calculateModularExponentiation(long base, long exponent, long mod) {
+        long x = 1; // This will hold the result of (base^exponent) % mod
+        long y = base; // This holds the current base value being squared
+
+        while (exponent > 0) {
+            // If exponent is odd, multiply the current base (y) with x
+            if (exponent % 2 == 1) {
+                x = x * y % mod; // Update result with current base
+            }
+            // Square the base for the next iteration
+            y = y * y % mod; // Update base to be y^2
+            exponent = exponent / 2; // Halve the exponent for next iteration
+        }
+
+        return x % mod; // Return final result after all iterations
+    }
+
+    /**
+     * Computes the Jacobi symbol (a/n), which is a generalization of the Legendre symbol.
+     *
+     * @param a the numerator
+     * @param num the denominator (must be an odd positive integer)
+     * @return the Jacobi symbol value: 1, -1, or 0
+     */
+    public int calculateJacobi(long a, long num) {
+        // Check if num is non-positive or even; Jacobi symbol is not defined in these cases
+        if (num <= 0 || num % 2 == 0) {
+            return 0;
+        }
+
+        a = a % num; // Reduce a modulo num to simplify calculations
+        int jacobi = 1; // Initialize Jacobi symbol value
+
+        while (a != 0) {
+            // While a is even, reduce it and adjust jacobi based on properties of num
+            while (a % 2 == 0) {
+                a /= 2; // Divide a by 2 until it becomes odd
+                long nMod8 = num % 8; // Get num modulo 8 to check conditions for jacobi adjustment
+                if (nMod8 == 3 || nMod8 == 5) {
+                    jacobi = -jacobi; // Flip jacobi sign based on properties of num modulo 8
+                }
+            }
+
+            long temp = a; // Temporarily store value of a
+            a = num; // Set a to be num for next iteration
+            num = temp; // Set num to be previous value of a
+
+            // Adjust jacobi based on properties of both numbers when both are odd and congruent to 3 modulo 4
+            if (a % 4 == 3 && num % 4 == 3) {
+                jacobi = -jacobi; // Flip jacobi sign again based on congruences
+            }
+
+            a = a % num; // Reduce a modulo num for next iteration of Jacobi computation
+        }
+
+        return (num == 1) ? jacobi : 0; // If num reduces to 1, return jacobi value, otherwise return 0 (not defined)
+    }
+
+    /**
+     * Performs the Solovay-Strassen primality test on a given number.
+     *
+     * @param num the number to be tested for primality
+     * @param iterations the number of iterations to run for accuracy
+     * @return true if num is likely prime, false if it is composite
+     */
+    public boolean solovayStrassen(long num, int iterations) {
+        if (num <= 1) {
+            return false; // Numbers <=1 are not prime by definition.
+        }
+        if (num <= 3) {
+            return true; // Numbers <=3 are prime.
+        }
+
+        for (int i = 0; i < iterations; i++) {
+            long r = Math.abs(random.nextLong() % (num - 1)) + 2; // Generate a non-negative random number.
+            long a = r % (num - 1) + 1; // Choose random 'a' in range [1, n-1].
+
+            long jacobi = (num + calculateJacobi(a, num)) % num;
+            // Calculate Jacobi symbol and adjust it modulo n.
+
+            long mod = calculateModularExponentiation(a, (num - 1) / 2, num);
+            // Calculate modular exponentiation: a^((n-1)/2) mod n.
+
+            if (jacobi == 0 || mod != jacobi) {
+                return false; // If Jacobi symbol is zero or doesn't match modular result, n is composite.
+            }
+        }
+
+        return true; // If no contradictions found after all iterations, n is likely prime.
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/SolovayStrassenPrimalityTestTest.java b/src/test/java/com/thealgorithms/maths/SolovayStrassenPrimalityTestTest.java
new file mode 100644
index 000000000000..18cc35266c8c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/SolovayStrassenPrimalityTestTest.java
@@ -0,0 +1,122 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+/**
+ * Unit tests for the {@link SolovayStrassenPrimalityTest} class.
+ * This class tests the functionality of the Solovay-Strassen primality test implementation.
+ */
+class SolovayStrassenPrimalityTestTest {
+
+    private static final int RANDOM_SEED = 123; // Seed for reproducibility
+    private SolovayStrassenPrimalityTest testInstance;
+
+    /**
+     * Sets up a new instance of {@link SolovayStrassenPrimalityTest}
+     * before each test case, using a fixed random seed for consistency.
+     */
+    @BeforeEach
+    void setUp() {
+        testInstance = SolovayStrassenPrimalityTest.getSolovayStrassenPrimalityTest(RANDOM_SEED);
+    }
+
+    /**
+     * Provides test cases for prime numbers with various values of n and k (iterations).
+     *
+     * @return an array of objects containing pairs of n and k values
+     */
+    static Object[][] primeNumbers() {
+        return new Object[][] {{2, 1}, {3, 1}, {5, 5}, {7, 10}, {11, 20}, {13, 10}, {17, 5}, {19, 1}};
+    }
+
+    /**
+     * Tests known prime numbers with various values of n and k (iterations).
+     *
+     * @param n the number to be tested for primality
+     * @param k the number of iterations to use in the primality test
+     */
+    @ParameterizedTest
+    @MethodSource("primeNumbers")
+    void testPrimeNumbersWithDifferentNAndK(int n, int k) {
+        assertTrue(testInstance.solovayStrassen(n, k), n + " should be prime");
+    }
+
+    /**
+     * Provides test cases for composite numbers with various values of n and k (iterations).
+     *
+     * @return an array of objects containing pairs of n and k values
+     */
+    static Object[][] compositeNumbers() {
+        return new Object[][] {{4, 1}, {6, 5}, {8, 10}, {9, 20}, {10, 1}, {12, 5}, {15, 10}};
+    }
+
+    /**
+     * Tests known composite numbers with various values of n and k (iterations).
+     *
+     * @param n the number to be tested for primality
+     * @param k the number of iterations to use in the primality test
+     */
+    @ParameterizedTest
+    @MethodSource("compositeNumbers")
+    void testCompositeNumbersWithDifferentNAndK(int n, int k) {
+        assertFalse(testInstance.solovayStrassen(n, k), n + " should be composite");
+    }
+
+    /**
+     * Tests edge cases for the primality test.
+     * This includes negative numbers and small integers (0 and 1).
+     */
+    @Test
+    void testEdgeCases() {
+        assertFalse(testInstance.solovayStrassen(-1, 10), "-1 should not be prime");
+        assertFalse(testInstance.solovayStrassen(0, 10), "0 should not be prime");
+        assertFalse(testInstance.solovayStrassen(1, 10), "1 should not be prime");
+
+        // Test small primes and composites
+        assertTrue(testInstance.solovayStrassen(2, 1), "2 is a prime number (single iteration)");
+        assertFalse(testInstance.solovayStrassen(9, 1), "9 is a composite number (single iteration)");
+
+        // Test larger primes and composites
+        long largePrime = 104729; // Known large prime number
+        long largeComposite = 104730; // Composite number (even)
+
+        assertTrue(testInstance.solovayStrassen(largePrime, 20), "104729 is a prime number");
+        assertFalse(testInstance.solovayStrassen(largeComposite, 20), "104730 is a composite number");
+
+        // Test very large numbers (may take longer)
+        long veryLargePrime = 512927357; // Known very large prime number
+        long veryLargeComposite = 512927358; // Composite number (even)
+
+        assertTrue(testInstance.solovayStrassen(veryLargePrime, 20), Long.MAX_VALUE - 1 + " is likely a prime number.");
+
+        assertFalse(testInstance.solovayStrassen(veryLargeComposite, 20), Long.MAX_VALUE + " is a composite number.");
+    }
+
+    /**
+     * Tests the Jacobi symbol calculation directly for known values.
+     * This verifies that the Jacobi symbol method behaves as expected.
+     */
+    @Test
+    void testJacobiSymbolCalculation() {
+        // Jacobi symbol (a/n) where n is odd and positive
+        int jacobi1 = testInstance.calculateJacobi(6, 11); // Should return -1
+        int jacobi2 = testInstance.calculateJacobi(5, 11); // Should return +1
+
+        assertEquals(-1, jacobi1);
+        assertEquals(+1, jacobi2);
+
+        // Edge case: Jacobi symbol with even n or non-positive n
+        int jacobi4 = testInstance.calculateJacobi(5, -11); // Should return 0 (invalid)
+        int jacobi5 = testInstance.calculateJacobi(5, 0); // Should return 0 (invalid)
+
+        assertEquals(0, jacobi4);
+        assertEquals(0, jacobi5);
+    }
+}

From 7326ab2c121ff7059bd17e5745afa7d70b98d0f0 Mon Sep 17 00:00:00 2001
From: Rupa <102663541+Rupa-Rd@users.noreply.github.com>
Date: Fri, 11 Oct 2024 02:16:43 +0530
Subject: [PATCH 0508/1338] Add Space Optimized Solution to Subset sum problem 
 (#5612)

---
 .../SubsetSumSpaceOptimized.java              | 35 +++++++++++++++++++
 .../SubsetSumSpaceOptimizedTest.java          | 18 ++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimizedTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java
new file mode 100644
index 000000000000..946da46cb292
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java
@@ -0,0 +1,35 @@
+package com.thealgorithms.dynamicprogramming;
+/*
+The Sum of Subset problem determines whether a subset of elements from a
+given array sums up to a specific target value.
+*/
+public final class SubsetSumSpaceOptimized {
+    private SubsetSumSpaceOptimized() {
+    }
+    /**
+     * This method checks whether the subset of an array
+     * contains a given sum or not. This is an space
+     * optimized solution using 1D boolean array
+     * Time Complexity: O(n * sum), Space complexity: O(sum)
+     *
+     * @param arr An array containing integers
+     * @param sum The target sum of the subset
+     * @return True or False
+     */
+    public static boolean isSubsetSum(int[] arr, int sum) {
+        int n = arr.length;
+        // Declare the boolean array with size sum + 1
+        boolean[] dp = new boolean[sum + 1];
+
+        // Initialize the first element as true
+        dp[0] = true;
+
+        // Find the subset sum using 1D array
+        for (int i = 0; i < n; i++) {
+            for (int j = sum; j >= arr[i]; j--) {
+                dp[j] = dp[j] || dp[j - arr[i]];
+            }
+        }
+        return dp[sum];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimizedTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimizedTest.java
new file mode 100644
index 000000000000..3a965f4e68b8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimizedTest.java
@@ -0,0 +1,18 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class SubsetSumSpaceOptimizedTest {
+
+    @Test
+    void basicCheck() {
+        assertTrue(SubsetSumSpaceOptimized.isSubsetSum(new int[] {7, 3, 2, 5, 8}, 14));
+        assertTrue(SubsetSumSpaceOptimized.isSubsetSum(new int[] {4, 3, 2, 1}, 5));
+        assertTrue(SubsetSumSpaceOptimized.isSubsetSum(new int[] {1, 7, 2, 9, 10}, 13));
+        assertFalse(SubsetSumSpaceOptimized.isSubsetSum(new int[] {1, 2, 7, 10, 9}, 14));
+        assertFalse(SubsetSumSpaceOptimized.isSubsetSum(new int[] {2, 15, 1, 6, 7}, 4));
+    }
+}

From 2040df88d94ab3d0c2bcec17f5b499b5ae644768 Mon Sep 17 00:00:00 2001
From: xuyang471 <2621860014@qq.com>
Date: Fri, 11 Oct 2024 13:47:36 +0800
Subject: [PATCH 0509/1338] Add Elliptic Curve Cryptography (#5700)

---
 .../java/com/thealgorithms/ciphers/ECC.java   | 236 ++++++++++++++++++
 .../com/thealgorithms/ciphers/ECCTest.java    | 106 ++++++++
 2 files changed, 342 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/ECC.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/ECCTest.java

diff --git a/src/main/java/com/thealgorithms/ciphers/ECC.java b/src/main/java/com/thealgorithms/ciphers/ECC.java
new file mode 100644
index 000000000000..7b1e37f0e1e1
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/ECC.java
@@ -0,0 +1,236 @@
+package com.thealgorithms.ciphers;
+
+import java.math.BigInteger;
+import java.security.SecureRandom;
+
+/**
+ * ECC - Elliptic Curve Cryptography
+ * Elliptic Curve Cryptography is a public-key cryptography method that uses the algebraic structure of
+ * elliptic curves over finite fields. ECC provides a higher level of security with smaller key sizes compared
+ * to other public-key methods like RSA, making it particularly suitable for environments where computational
+ * resources are limited, such as mobile devices and embedded systems.
+ *
+ * This class implements elliptic curve cryptography, providing encryption and decryption
+ * functionalities based on public and private key pairs.
+ *
+ * @author xuyang
+ */
+public class ECC {
+
+    private BigInteger privateKey; // Private key used for decryption
+    private ECPoint publicKey; // Public key used for encryption
+    private EllipticCurve curve; // Elliptic curve used in cryptography
+    private ECPoint basePoint; // Base point G on the elliptic curve
+
+    public ECC(int bits) {
+        generateKeys(bits); // Generates public-private key pair
+    }
+
+    public EllipticCurve getCurve() {
+        return curve; // Returns the elliptic curve
+    }
+
+    public void setCurve(EllipticCurve curve) {
+        this.curve = curve;
+    }
+
+    // Getter and Setter for private key
+    public BigInteger getPrivateKey() {
+        return privateKey;
+    }
+
+    public void setPrivateKey(BigInteger privateKey) {
+        this.privateKey = privateKey;
+    }
+
+    /**
+     * Encrypts the message using the public key.
+     * The message is transformed into an ECPoint and encrypted with elliptic curve operations.
+     *
+     * @param message The plain message to be encrypted
+     * @return The encrypted message as an array of ECPoints (R, S)
+     */
+    public ECPoint[] encrypt(String message) {
+        BigInteger m = new BigInteger(message.getBytes()); // Convert message to BigInteger
+        SecureRandom r = new SecureRandom(); // Generate random value for k
+        BigInteger k = new BigInteger(curve.getFieldSize(), r); // Generate random scalar k
+
+        // Calculate point r = k * G, where G is the base point
+        ECPoint rPoint = basePoint.multiply(k, curve.getP(), curve.getA());
+
+        // Calculate point s = k * publicKey + encodedMessage
+        ECPoint sPoint = publicKey.multiply(k, curve.getP(), curve.getA()).add(curve.encodeMessage(m), curve.getP(), curve.getA());
+
+        return new ECPoint[] {rPoint, sPoint}; // Return encrypted message as two ECPoints
+    }
+
+    /**
+     * Decrypts the encrypted message using the private key.
+     * The decryption process is the reverse of encryption, recovering the original message.
+     *
+     * @param encryptedMessage The encrypted message as an array of ECPoints (R, S)
+     * @return The decrypted plain message as a String
+     */
+    public String decrypt(ECPoint[] encryptedMessage) {
+        ECPoint rPoint = encryptedMessage[0]; // First part of ciphertext
+        ECPoint sPoint = encryptedMessage[1]; // Second part of ciphertext
+
+        // Perform decryption: s - r * privateKey
+        ECPoint decodedMessage = sPoint.subtract(rPoint.multiply(privateKey, curve.getP(), curve.getA()), curve.getP(), curve.getA());
+
+        BigInteger m = curve.decodeMessage(decodedMessage); // Decode the message from ECPoint
+
+        return new String(m.toByteArray()); // Convert BigInteger back to String
+    }
+
+    /**
+     * Generates a new public-private key pair for encryption and decryption.
+     *
+     * @param bits The size (in bits) of the keys to generate
+     */
+    public final void generateKeys(int bits) {
+        SecureRandom r = new SecureRandom();
+        curve = new EllipticCurve(bits); // Initialize a new elliptic curve
+        basePoint = curve.getBasePoint(); // Set the base point G
+
+        // Generate private key as a random BigInteger
+        privateKey = new BigInteger(bits, r);
+
+        // Generate public key as the point publicKey = privateKey * G
+        publicKey = basePoint.multiply(privateKey, curve.getP(), curve.getA());
+    }
+
+    /**
+     * Class representing an elliptic curve with the form y^2 = x^3 + ax + b.
+     */
+    public static class EllipticCurve {
+        private final BigInteger a; // Coefficient a in the curve equation
+        private final BigInteger b; // Coefficient b in the curve equation
+        private final BigInteger p; // Prime number p, defining the finite field
+        private final ECPoint basePoint; // Base point G on the curve
+
+        // Constructor with explicit parameters for a, b, p, and base point
+        public EllipticCurve(BigInteger a, BigInteger b, BigInteger p, ECPoint basePoint) {
+            this.a = a;
+            this.b = b;
+            this.p = p;
+            this.basePoint = basePoint;
+        }
+
+        // Constructor that randomly generates the curve parameters
+        public EllipticCurve(int bits) {
+            SecureRandom r = new SecureRandom();
+            this.p = BigInteger.probablePrime(bits, r); // Random prime p
+            this.a = new BigInteger(bits, r); // Random coefficient a
+            this.b = new BigInteger(bits, r); // Random coefficient b
+            this.basePoint = new ECPoint(BigInteger.valueOf(4), BigInteger.valueOf(8)); // Fixed base point G
+        }
+
+        public ECPoint getBasePoint() {
+            return basePoint;
+        }
+
+        public BigInteger getP() {
+            return p;
+        }
+
+        public BigInteger getA() {
+            return a;
+        }
+
+        public BigInteger getB() {
+            return b;
+        }
+
+        public int getFieldSize() {
+            return p.bitLength();
+        }
+
+        public ECPoint encodeMessage(BigInteger message) {
+            // Simple encoding of a message as an ECPoint (this is a simplified example)
+            return new ECPoint(message, message);
+        }
+
+        public BigInteger decodeMessage(ECPoint point) {
+            return point.getX(); // Decode the message from ECPoint (simplified)
+        }
+    }
+
+    /**
+     * Class representing a point on the elliptic curve.
+     */
+    public static class ECPoint {
+        private final BigInteger x; // X-coordinate of the point
+        private final BigInteger y; // Y-coordinate of the point
+
+        public ECPoint(BigInteger x, BigInteger y) {
+            this.x = x;
+            this.y = y;
+        }
+
+        public BigInteger getX() {
+            return x;
+        }
+
+        public BigInteger getY() {
+            return y;
+        }
+
+        @Override
+        public String toString() {
+            return "ECPoint(x=" + x.toString() + ", y=" + y.toString() + ")";
+        }
+
+        /**
+         * Add two points on the elliptic curve.
+         */
+        public ECPoint add(ECPoint other, BigInteger p, BigInteger a) {
+            if (this.x.equals(BigInteger.ZERO) && this.y.equals(BigInteger.ZERO)) {
+                return other; // If this point is the identity, return the other point
+            }
+            if (other.x.equals(BigInteger.ZERO) && other.y.equals(BigInteger.ZERO)) {
+                return this; // If the other point is the identity, return this point
+            }
+
+            BigInteger lambda;
+            if (this.equals(other)) {
+                // Special case: point doubling
+                lambda = this.x.pow(2).multiply(BigInteger.valueOf(3)).add(a).multiply(this.y.multiply(BigInteger.valueOf(2)).modInverse(p)).mod(p);
+            } else {
+                // General case: adding two different points
+                lambda = other.y.subtract(this.y).multiply(other.x.subtract(this.x).modInverse(p)).mod(p);
+            }
+
+            BigInteger xr = lambda.pow(2).subtract(this.x).subtract(other.x).mod(p);
+            BigInteger yr = lambda.multiply(this.x.subtract(xr)).subtract(this.y).mod(p);
+
+            return new ECPoint(xr, yr);
+        }
+
+        /**
+         * Subtract two points on the elliptic curve.
+         */
+        public ECPoint subtract(ECPoint other, BigInteger p, BigInteger a) {
+            ECPoint negOther = new ECPoint(other.x, p.subtract(other.y)); // Negate the Y coordinate
+            return this.add(negOther, p, a); // Add the negated point
+        }
+
+        /**
+         * Multiply a point by a scalar (repeated addition).
+         */
+        public ECPoint multiply(BigInteger k, BigInteger p, BigInteger a) {
+            ECPoint result = new ECPoint(BigInteger.ZERO, BigInteger.ZERO); // Identity point
+            ECPoint addend = this;
+
+            while (k.signum() > 0) {
+                if (k.testBit(0)) {
+                    result = result.add(addend, p, a); // Add the current point
+                }
+                addend = addend.add(addend, p, a); // Double the point
+                k = k.shiftRight(1); // Divide k by 2
+            }
+
+            return result;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/ECCTest.java b/src/test/java/com/thealgorithms/ciphers/ECCTest.java
new file mode 100644
index 000000000000..701f801af1c8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/ECCTest.java
@@ -0,0 +1,106 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+import java.math.BigInteger;
+import org.junit.jupiter.api.Test;
+
+/**
+ * ECCTest - Unit tests for the ECC (Elliptic Curve Cryptography) implementation.
+ * This class contains various test cases to validate the encryption and decryption functionalities.
+ * It ensures the correctness and randomness of ECC operations.
+ *
+ * @author xuyang
+ */
+public class ECCTest {
+    ECC ecc = new ECC(256); // Generate a 256-bit ECC key pair. Calls generateKeys(bits) to create keys including privateKey and publicKey.
+
+    /**
+     * Test the encryption functionality: convert plaintext to ciphertext and output relevant encryption data.
+     */
+    @Test
+    void testEncrypt() {
+        String textToEncrypt = "Elliptic Curve Cryptography";
+
+        ECC.ECPoint[] cipherText = ecc.encrypt(textToEncrypt); // Perform encryption
+
+        // Output private key information
+        System.out.println("Private Key: " + ecc.getPrivateKey());
+
+        // Output elliptic curve parameters
+        ECC.EllipticCurve curve = ecc.getCurve();
+        System.out.println("Elliptic Curve Parameters:");
+        System.out.println("a: " + curve.getA());
+        System.out.println("b: " + curve.getB());
+        System.out.println("p: " + curve.getP());
+        System.out.println("Base Point G: " + curve.getBasePoint());
+
+        // Verify that the ciphertext is not empty
+        assertEquals(cipherText.length, 2); // Check if the ciphertext contains two points (R and S)
+
+        // Output the encrypted coordinate points
+        System.out.println("Encrypted Points:");
+        for (ECC.ECPoint point : cipherText) {
+            System.out.println(point); // Calls ECPoint's toString() method
+        }
+    }
+
+    /**
+     * Test the decryption functionality: convert ciphertext back to plaintext using known private key and elliptic curve parameters.
+     */
+    @Test
+    void testDecryptWithKnownValues() {
+        // 1. Define the known private key
+        BigInteger knownPrivateKey = new BigInteger("28635978664199231399690075483195602260051035216440375973817268759912070302603");
+
+        // 2. Define the known elliptic curve parameters
+        BigInteger a = new BigInteger("64505295837372135469230827475895976532873592609649950000895066186842236488761"); // Replace with known a value
+        BigInteger b = new BigInteger("89111668838830965251111555638616364203833415376750835901427122343021749874324"); // Replace with known b value
+        BigInteger p = new BigInteger("107276428198310591598877737561885175918069075479103276920057092968372930219921"); // Replace with known p value
+        ECC.ECPoint basePoint = new ECC.ECPoint(new BigInteger("4"), new BigInteger("8")); // Replace with known base point coordinates
+
+        // 3. Create the elliptic curve object
+        ECC.EllipticCurve curve = new ECC.EllipticCurve(a, b, p, basePoint);
+
+        // 4. Define the known ciphertext containing two ECPoints (R, S)
+        ECC.ECPoint rPoint = new ECC.ECPoint(new BigInteger("103077584019003058745849614420912636617007257617156724481937620119667345237687"), new BigInteger("68193862907937248121971710522760893811582068323088661566426323952783362061817"));
+        ECC.ECPoint sPoint = new ECC.ECPoint(new BigInteger("31932232426664380635434632300383525435115368414929679432313910646436992147798"), new BigInteger("77299754382292904069123203569944908076819220797512755280123348910207308129766"));
+        ECC.ECPoint[] cipherText = new ECC.ECPoint[] {rPoint, sPoint};
+
+        // 5. Create an ECC instance and set the private key and curve parameters
+        ecc.setPrivateKey(knownPrivateKey); // Use setter method to set the private key
+        ecc.setCurve(curve); // Use setter method to set the elliptic curve
+
+        // 6. Decrypt the known ciphertext
+        String decryptedMessage = ecc.decrypt(cipherText);
+
+        // 7. Compare the decrypted plaintext with the expected value
+        String expectedMessage = "Elliptic Curve Cryptography"; // Expected plaintext
+        assertEquals(expectedMessage, decryptedMessage);
+    }
+
+    /**
+     * Test that encrypting the same plaintext with ECC produces different ciphertexts.
+     */
+    @Test
+    void testCipherTextRandomness() {
+        String message = "Elliptic Curve Cryptography";
+
+        ECC.ECPoint[] cipherText1 = ecc.encrypt(message);
+        ECC.ECPoint[] cipherText2 = ecc.encrypt(message);
+
+        assertNotEquals(cipherText1, cipherText2); // Ensure that the two ciphertexts are different
+    }
+
+    /**
+     * Test the entire ECC encryption and decryption process.
+     */
+    @Test
+    void testECCEncryptionAndDecryption() {
+        String textToEncrypt = "Elliptic Curve Cryptography";
+        ECC.ECPoint[] cipherText = ecc.encrypt(textToEncrypt);
+        String decryptedText = ecc.decrypt(cipherText);
+        assertEquals(textToEncrypt, decryptedText); // Verify that the decrypted text matches the original text
+    }
+}

From 233842857838c9be50c8f2f4c6b34a86c07a1583 Mon Sep 17 00:00:00 2001
From: Varnan Rathod <119997446+Krounosity@users.noreply.github.com>
Date: Fri, 11 Oct 2024 11:35:26 +0530
Subject: [PATCH 0510/1338] Add cipher class, cipher tests, enhance docs in
 'AtbashCipher.java' (#5690)

---
 DIRECTORY.md                                  |  2 +
 .../thealgorithms/ciphers/AtbashCipher.java   | 71 +++++++++++++++++++
 .../com/thealgorithms/ciphers/AtbashTest.java | 28 ++++++++
 3 files changed, 101 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/AtbashCipher.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/AtbashTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7ebc176b02cf..e022ddc23e5a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -50,6 +50,7 @@
             * [AES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AES.java)
             * [AESEncryption](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AESEncryption.java)
             * [AffineCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AffineCipher.java)
+            * [AtbashCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java)
             * [Autokey](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Autokey.java)
             * [Blowfish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Blowfish.java)
             * [Caesar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Caesar.java)
@@ -663,6 +664,7 @@
               * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
             * [AESEncryptionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java)
             * [AffineCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java)
+            * [AtbashTest](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AtbashTest.java)
             * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
             * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
             * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
diff --git a/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java b/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java
new file mode 100644
index 000000000000..c3b673144c63
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java
@@ -0,0 +1,71 @@
+package com.thealgorithms.ciphers;
+
+/**
+ * The Atbash cipher is a simple substitution cipher that replaces each letter
+ * in the alphabet with its reverse.
+ * For example, 'A' becomes 'Z', 'B' becomes 'Y', and so on. It works
+ * identically for both uppercase and lowercase letters.
+ * It's a symmetric cipher, meaning applying it twice returns the original text.
+ * Hence, the encrypting and the decrypting functions are identical
+ * @author https://github.com/Krounosity
+ * Learn more: https://en.wikipedia.org/wiki/Atbash
+ */
+
+public class AtbashCipher {
+
+    private String toConvert;
+
+    // Default constructor.
+    AtbashCipher() {
+    }
+
+    // String setting constructor.
+    AtbashCipher(String str) {
+        toConvert = str;
+    }
+
+    // String getter method.
+    public String getString() {
+        return toConvert;
+    }
+
+    // String setter method.
+    public void setString(String str) {
+        toConvert = str;
+    }
+
+    // Checking whether the current character is capital.
+    private boolean isCapital(char ch) {
+        return ch >= 'A' && ch <= 'Z';
+    }
+
+    // Checking whether the current character is smallcased.
+    private boolean isSmall(char ch) {
+        return ch >= 'a' && ch <= 'z';
+    }
+
+    // Converting text to atbash cipher code or vice versa.
+    public String convert() {
+
+        // Using StringBuilder to store new string.
+        StringBuilder convertedString = new StringBuilder();
+
+        // Iterating for each character.
+        for (char ch : toConvert.toCharArray()) {
+
+            // If the character is smallcased.
+            if (isSmall(ch)) {
+                convertedString.append((char) ('z' - (ch - 'a')));
+            }
+            // If the character is capital cased.
+            else if (isCapital(ch)) {
+                convertedString.append((char) ('Z' - (ch - 'A')));
+            }
+            // Non-alphabetical character.
+            else {
+                convertedString.append(ch);
+            }
+        }
+        return convertedString.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/AtbashTest.java b/src/test/java/com/thealgorithms/ciphers/AtbashTest.java
new file mode 100644
index 000000000000..26812cf2b0d4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/AtbashTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class AtbashTest {
+
+    @Test
+    public void atbashEncrypt() {
+        AtbashCipher normalToEncrypt = new AtbashCipher("Hello World! 123, @cipher abcDEF ZYX 987 madam zzZ Palindrome!");
+        String expectedText = "Svool Dliow! 123, @xrksvi zyxWVU ABC 987 nzwzn aaA Kzormwilnv!";
+
+        normalToEncrypt.setString(normalToEncrypt.convert());
+
+        assertEquals(expectedText, normalToEncrypt.getString());
+    }
+
+    @Test
+    public void atbashDecrypt() {
+        AtbashCipher encryptToNormal = new AtbashCipher("Svool Dliow! 123, @xrksvi zyxWVU ABC 987 nzwzn aaA Kzormwilnv!");
+        String expectedText = "Hello World! 123, @cipher abcDEF ZYX 987 madam zzZ Palindrome!";
+
+        encryptToNormal.setString(encryptToNormal.convert());
+
+        assertEquals(expectedText, encryptToNormal.getString());
+    }
+}

From 0ca43981885ea294987b33ee03ea03645c2061ca Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 11 Oct 2024 19:28:34 +0530
Subject: [PATCH 0511/1338] feat: Add `RandomSearch` new algorithm with Junit
 tests (#5701)

---
 DIRECTORY.md                                  | 10 ++-
 .../thealgorithms/searches/RandomSearch.java  | 45 ++++++++++
 .../searches/RandomSearchTest.java            | 87 +++++++++++++++++++
 3 files changed, 141 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/com/thealgorithms/searches/RandomSearch.java
 create mode 100644 src/test/java/com/thealgorithms/searches/RandomSearchTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index e022ddc23e5a..d0f50b421297 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -56,6 +56,7 @@
             * [Caesar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Caesar.java)
             * [ColumnarTranspositionCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java)
             * [DES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/DES.java)
+            * [ECC](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ECC.java)
             * [HillCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/HillCipher.java)
             * [PlayfairCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java)
             * [Polybius](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Polybius.java)
@@ -275,6 +276,7 @@
             * [ShortestCommonSupersequenceLength](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java)
             * [SubsetCount](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java)
             * [SubsetSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java)
+            * [SubsetSumSpaceOptimized](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java)
             * [SumOfSubset](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java)
             * [Tribonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java)
             * [UniquePaths](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java)
@@ -396,6 +398,7 @@
             * [SecondMinMax](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SecondMinMax.java)
             * [SieveOfEratosthenes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java)
             * [SimpsonIntegration](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java)
+            * [SolovayStrassenPrimalityTest](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java)
             * [SquareFreeInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareFreeInteger.java)
             * [SquareRootWithBabylonianMethod](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java)
             * [SquareRootWithNewtonRaphsonMethod](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonMethod.java)
@@ -511,6 +514,7 @@
             * [PerfectBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java)
             * [QuickSelect](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/QuickSelect.java)
             * [RabinKarpAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java)
+            * [RandomSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RandomSearch.java)
             * [RecursiveBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java)
             * [RowColumnWiseSorted2dArrayBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java)
             * [SaddlebackSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java)
@@ -664,12 +668,13 @@
               * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
             * [AESEncryptionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java)
             * [AffineCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java)
-            * [AtbashTest](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AtbashTest.java)
+            * [AtbashTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AtbashTest.java)
             * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
             * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
             * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
             * [ColumnarTranspositionCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java)
             * [DESTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DESTest.java)
+            * [ECCTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/ECCTest.java)
             * [HillCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/HillCipherTest.java)
             * [PlayfairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java)
             * [PolybiusTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
@@ -829,6 +834,7 @@
             * [RodCuttingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java)
             * [ShortestCommonSupersequenceLengthTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLengthTest.java)
             * [SubsetCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java)
+            * [SubsetSumSpaceOptimizedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimizedTest.java)
             * [SubsetSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java)
             * [SumOfSubsetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java)
             * [TribonacciTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java)
@@ -935,6 +941,7 @@
             * [ReverseNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ReverseNumberTest.java)
             * [SecondMinMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java)
             * [SieveOfEratosthenesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java)
+            * [SolovayStrassenPrimalityTestTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SolovayStrassenPrimalityTestTest.java)
             * [SquareFreeIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java)
             * [SquareRootwithBabylonianMethodTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareRootwithBabylonianMethodTest.java)
             * [SquareRootWithNewtonRaphsonTestMethod](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonTestMethod.java)
@@ -1018,6 +1025,7 @@
             * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
             * [QuickSelectTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/QuickSelectTest.java)
             * [RabinKarpAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java)
+            * [RandomSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RandomSearchTest.java)
             * [RecursiveBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java)
             * [RowColumnWiseSorted2dArrayBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java)
             * [SaddlebackSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SaddlebackSearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/RandomSearch.java b/src/main/java/com/thealgorithms/searches/RandomSearch.java
new file mode 100644
index 000000000000..3417ff7ddb21
--- /dev/null
+++ b/src/main/java/com/thealgorithms/searches/RandomSearch.java
@@ -0,0 +1,45 @@
+package com.thealgorithms.searches;
+
+import com.thealgorithms.devutils.searches.SearchAlgorithm;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+
+/**
+ * A Random Search algorithm that randomly selects an index and checks if the
+ * value at that index matches the target. It repeats the process until it
+ * finds the target or checks all elements.
+ *
+ * <p>
+ * Time Complexity: O(n) in the worst case.
+ * </p>
+ *
+ * @author Hardvan
+ */
+public class RandomSearch implements SearchAlgorithm {
+
+    private final Random random = new Random();
+
+    /**
+     * Finds the index of a given element using random search.
+     *
+     * @param array Array to search through
+     * @param key Element to search for
+     * @return Index of the element if found, -1 otherwise
+     */
+    @Override
+    public <T extends Comparable<T>> int find(T[] array, T key) {
+        Set<Integer> visitedIndices = new HashSet<>();
+        int size = array.length;
+
+        while (visitedIndices.size() < size) {
+            int randomIndex = random.nextInt(size);
+            if (array[randomIndex].compareTo(key) == 0) {
+                return randomIndex;
+            }
+            visitedIndices.add(randomIndex);
+        }
+
+        return -1;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/searches/RandomSearchTest.java b/src/test/java/com/thealgorithms/searches/RandomSearchTest.java
new file mode 100644
index 000000000000..0a1dbeafd888
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/RandomSearchTest.java
@@ -0,0 +1,87 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class RandomSearchTest {
+
+    private RandomSearch randomSearch;
+
+    @BeforeEach
+    void setUp() {
+        randomSearch = new RandomSearch();
+    }
+
+    @Test
+    void testElementFound() {
+        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 5;
+        int index = randomSearch.find(array, key);
+
+        assertNotEquals(-1, index, "Element should be found in the array.");
+        assertEquals(key, array[index], "Element found should match the key.");
+    }
+
+    @Test
+    void testElementNotFound() {
+        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 11;
+        int index = randomSearch.find(array, key);
+
+        assertEquals(-1, index, "Element not present in the array should return -1.");
+    }
+
+    @Test
+    void testEmptyArray() {
+        Integer[] emptyArray = {};
+        Integer key = 5;
+        int index = randomSearch.find(emptyArray, key);
+
+        assertEquals(-1, index, "Searching in an empty array should return -1.");
+    }
+
+    @Test
+    void testSingleElementArrayFound() {
+        Integer[] array = {5};
+        Integer key = 5;
+        int index = randomSearch.find(array, key);
+
+        assertEquals(0, index, "The key should be found at index 0 in a single-element array.");
+    }
+
+    @Test
+    void testSingleElementArrayNotFound() {
+        Integer[] array = {1};
+        Integer key = 5;
+        int index = randomSearch.find(array, key);
+
+        assertEquals(-1, index, "The key should not be found in a single-element array if it does not match.");
+    }
+
+    @Test
+    void testDuplicateElementsFound() {
+        Integer[] array = {1, 2, 3, 4, 5, 5, 5, 7, 8, 9, 10};
+        Integer key = 5;
+        int index = randomSearch.find(array, key);
+
+        assertNotEquals(-1, index, "The key should be found in the array with duplicates.");
+        assertEquals(key, array[index], "The key found should be 5.");
+    }
+
+    @Test
+    void testLargeArray() {
+        Integer[] largeArray = new Integer[1000];
+        for (int i = 0; i < largeArray.length; i++) {
+            largeArray[i] = i + 1; // Fill with values 1 to 1000
+        }
+
+        Integer key = 500;
+        int index = randomSearch.find(largeArray, key);
+
+        assertNotEquals(-1, index, "The key should be found in the large array.");
+        assertEquals(key, largeArray[index], "The key found should match 500.");
+    }
+}

From 1c978c52f1252fdaea68e01cb056ffb396589190 Mon Sep 17 00:00:00 2001
From: Saahil Mahato <115351000+saahil-mahato@users.noreply.github.com>
Date: Fri, 11 Oct 2024 19:58:51 +0545
Subject: [PATCH 0512/1338] feat: add karatsuba multiplication (#5719)

* feat: add karatsuba multiplication

* fix: fallback size

* fix: big integer instances

---------

Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 .../maths/KaratsubaMultiplication.java        | 93 +++++++++++++++++++
 .../maths/KaratsubaMultiplicationTest.java    | 58 ++++++++++++
 2 files changed, 151 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/KaratsubaMultiplication.java
 create mode 100644 src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java

diff --git a/src/main/java/com/thealgorithms/maths/KaratsubaMultiplication.java b/src/main/java/com/thealgorithms/maths/KaratsubaMultiplication.java
new file mode 100644
index 000000000000..298fcb7e85f8
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/KaratsubaMultiplication.java
@@ -0,0 +1,93 @@
+package com.thealgorithms.maths;
+
+import java.math.BigInteger;
+
+/**
+ * This class provides an implementation of the Karatsuba multiplication algorithm.
+ *
+ * <p>
+ * Karatsuba multiplication is a divide-and-conquer algorithm for multiplying two large
+ * numbers. It is faster than the classical multiplication algorithm and reduces the
+ * time complexity to O(n^1.585) by breaking the multiplication of two n-digit numbers
+ * into three multiplications of n/2-digit numbers.
+ * </p>
+ *
+ * <p>
+ * The main idea of the Karatsuba algorithm is based on the following observation:
+ * </p>
+ *
+ * <pre>
+ * Let x and y be two numbers:
+ * x = a * 10^m + b
+ * y = c * 10^m + d
+ *
+ * Then, the product of x and y can be expressed as:
+ * x * y = (a * c) * 10^(2*m) + ((a * d) + (b * c)) * 10^m + (b * d)
+ * </pre>
+ *
+ * The Karatsuba algorithm calculates this more efficiently by reducing the number of
+ * multiplications from four to three by using the identity:
+ *
+ * <pre>
+ * (a + b)(c + d) = ac + ad + bc + bd
+ * </pre>
+ *
+ * <p>
+ * The recursion continues until the numbers are small enough to multiply directly using
+ * the traditional method.
+ * </p>
+ */
+public final class KaratsubaMultiplication {
+
+    /**
+     * Private constructor to hide the implicit public constructor
+     */
+    private KaratsubaMultiplication() {
+    }
+
+    /**
+     * Multiplies two large numbers using the Karatsuba algorithm.
+     *
+     * <p>
+     * This method recursively splits the numbers into smaller parts until they are
+     * small enough to be multiplied directly using the traditional method.
+     * </p>
+     *
+     * @param x The first large number to be multiplied (BigInteger).
+     * @param y The second large number to be multiplied (BigInteger).
+     * @return The product of the two numbers (BigInteger).
+     */
+    public static BigInteger karatsuba(BigInteger x, BigInteger y) {
+        // Base case: when numbers are small enough, use direct multiplication
+        // If the number is 4 bits or smaller, switch to the classical method
+        if (x.bitLength() <= 4 || y.bitLength() <= 4) {
+            return x.multiply(y);
+        }
+
+        // Find the maximum bit length of the two numbers
+        int n = Math.max(x.bitLength(), y.bitLength());
+
+        // Split the numbers in the middle
+        int m = n / 2;
+
+        // High and low parts of the first number x (x = a * 10^m + b)
+        BigInteger high1 = x.shiftRight(m); // a = x / 2^m (higher part)
+        BigInteger low1 = x.subtract(high1.shiftLeft(m)); // b = x - a * 2^m (lower part)
+
+        // High and low parts of the second number y (y = c * 10^m + d)
+        BigInteger high2 = y.shiftRight(m); // c = y / 2^m (higher part)
+        BigInteger low2 = y.subtract(high2.shiftLeft(m)); // d = y - c * 2^m (lower part)
+
+        // Recursively calculate three products
+        BigInteger z0 = karatsuba(low1, low2); // z0 = b * d (low1 * low2)
+        BigInteger z1 = karatsuba(low1.add(high1), low2.add(high2)); // z1 = (a + b) * (c + d)
+        BigInteger z2 = karatsuba(high1, high2); // z2 = a * c (high1 * high2)
+
+        // Combine the results using Karatsuba's formula
+        // z0 + ((z1 - z2 - z0) << m) + (z2 << 2m)
+        return z2
+            .shiftLeft(2 * m) // z2 * 10^(2*m)
+            .add(z1.subtract(z2).subtract(z0).shiftLeft(m)) // (z1 - z2 - z0) * 10^m
+            .add(z0); // z0
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java b/src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java
new file mode 100644
index 000000000000..e184d998724a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.math.BigInteger;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+/**
+ * Unit test class for {@link KaratsubaMultiplication} class.
+ *
+ * <p>
+ * This class tests various edge cases and normal cases for the
+ * Karatsuba multiplication algorithm implemented in the KaratsubaMultiplication class.
+ * It uses parameterized tests to handle multiple test cases.
+ * </p>
+ */
+class KaratsubaMultiplicationTest {
+
+    /**
+     * Provides test data for the parameterized test.
+     * Each entry in the stream contains three elements: x, y, and the expected result.
+     *
+     * @return a stream of arguments for the parameterized test
+     */
+    static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            // Test case 1: Two small numbers
+            Arguments.of(new BigInteger("1234"), new BigInteger("5678"), new BigInteger("7006652")),
+            // Test case 2: Two large numbers
+            Arguments.of(new BigInteger("342364"), new BigInteger("393958"), new BigInteger("134877036712")),
+            // Test case 3: One number is zero
+            Arguments.of(BigInteger.ZERO, new BigInteger("5678"), BigInteger.ZERO),
+            // Test case 4: Both numbers are zero
+            Arguments.of(BigInteger.ZERO, BigInteger.ZERO, BigInteger.ZERO),
+            // Test case 5: Single-digit numbers
+            Arguments.of(new BigInteger("9"), new BigInteger("8"), new BigInteger("72")));
+    }
+
+    /**
+     * Parameterized test for Karatsuba multiplication.
+     *
+     * <p>
+     * This method runs the Karatsuba multiplication algorithm for multiple test cases.
+     * </p>
+     *
+     * @param x the first number to multiply
+     * @param y the second number to multiply
+     * @param expected the expected result of x * y
+     */
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testKaratsubaMultiplication(BigInteger x, BigInteger y, BigInteger expected) {
+        assertEquals(expected, KaratsubaMultiplication.karatsuba(x, y));
+    }
+}

From 2a167f4bc333a4ba8e4b96e561e37b9665c1a896 Mon Sep 17 00:00:00 2001
From: Giulio Tantaro <giulio.tantaro@gmail.com>
Date: Fri, 11 Oct 2024 21:21:13 +0200
Subject: [PATCH 0513/1338] Add tests Sudoku (#5722)

* Add tests Sudoku

* Fix

* Update file

---------

Co-authored-by: Giulio Tantaro <giulio.tantaro@codeploy.it>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 .../com/thealgorithms/others/SudokuTest.java  | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/others/SudokuTest.java

diff --git a/src/test/java/com/thealgorithms/others/SudokuTest.java b/src/test/java/com/thealgorithms/others/SudokuTest.java
new file mode 100644
index 000000000000..5018b2768302
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/SudokuTest.java
@@ -0,0 +1,38 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class SudokuTest {
+
+    @Test
+    void testIsSafe2() {
+        int[][] board = {{3, 0, 6, 5, 0, 8, 4, 0, 0}, {5, 2, 0, 0, 0, 0, 0, 0, 0}, {0, 8, 7, 0, 0, 0, 0, 3, 1}, {0, 0, 3, 0, 1, 0, 0, 8, 0}, {9, 0, 0, 8, 6, 3, 0, 0, 5}, {0, 5, 0, 0, 9, 0, 6, 0, 0}, {1, 3, 0, 0, 0, 0, 2, 5, 0}, {0, 0, 0, 0, 0, 0, 0, 7, 4}, {0, 0, 5, 2, 0, 6, 3, 0, 0}};
+
+        assertFalse(Sudoku.isSafe(board, 0, 1, 3));
+        assertTrue(Sudoku.isSafe(board, 1, 2, 1));
+        assertThrows(ArrayIndexOutOfBoundsException.class, () -> { Sudoku.isSafe(board, 10, 10, 5); });
+        assertThrows(ArrayIndexOutOfBoundsException.class, () -> { Sudoku.isSafe(board, -1, 0, 5); });
+    }
+
+    @Test
+    void testSolveSudoku() {
+        int[][] board = {{3, 0, 6, 5, 0, 8, 4, 0, 0}, {5, 2, 0, 0, 0, 0, 0, 0, 0}, {0, 8, 7, 0, 0, 0, 0, 3, 1}, {0, 0, 3, 0, 1, 0, 0, 8, 0}, {9, 0, 0, 8, 6, 3, 0, 0, 5}, {0, 5, 0, 0, 9, 0, 6, 0, 0}, {1, 3, 0, 0, 0, 0, 2, 5, 0}, {0, 0, 0, 0, 0, 0, 0, 7, 4}, {0, 0, 5, 2, 0, 6, 3, 0, 0}};
+
+        assertTrue(Sudoku.solveSudoku(board, board.length));
+        assertEquals(1, board[0][1]);
+        assertThrows(ArrayIndexOutOfBoundsException.class, () -> { Sudoku.solveSudoku(board, 10); });
+        assertTrue(Sudoku.solveSudoku(board, -1));
+    }
+
+    @Test
+    void testUnsolvableSudoku() {
+        int[][] unsolvableBoard = {{5, 1, 6, 8, 4, 9, 7, 3, 2}, {3, 0, 7, 6, 0, 5, 0, 0, 0}, {8, 0, 9, 7, 0, 0, 0, 6, 5}, {1, 3, 5, 0, 6, 0, 9, 0, 7}, {4, 7, 2, 5, 9, 1, 0, 0, 6}, {9, 6, 8, 3, 7, 0, 0, 5, 0}, {2, 5, 3, 1, 8, 6, 0, 7, 4}, {6, 8, 4, 2, 5, 7, 3, 9, 0}, {7, 9, 1, 4, 3, 0, 5, 0, 0}};
+
+        assertFalse(Sudoku.solveSudoku(unsolvableBoard, unsolvableBoard.length));
+    }
+}

From 966b4e369dc5a8097e3ee0ff16b5fdd91c187d8a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 12 Oct 2024 11:30:12 +0530
Subject: [PATCH 0514/1338] feat: Add ClearLeftmostSetBit new algorithm with
 Junit tests (#5702)

---
 DIRECTORY.md                                  |  5 +++
 .../bitmanipulation/ClearLeftmostSetBit.java  | 39 +++++++++++++++++++
 .../ClearLeftmostSetBitTest.java              | 16 ++++++++
 3 files changed, 60 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index d0f50b421297..51af99583ed7 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -24,6 +24,7 @@
             * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
           * bitmanipulation
             * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
+            * [ClearLeftmostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java)
             * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
             * [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
             * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
@@ -355,6 +356,7 @@
             * [JosephusProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/JosephusProblem.java)
             * [JugglerSequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/JugglerSequence.java)
             * [KaprekarNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java)
+            * [KaratsubaMultiplication](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KaratsubaMultiplication.java)
             * [KeithNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KeithNumber.java)
             * [KrishnamurthyNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java)
             * [LeastCommonMultiple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java)
@@ -646,6 +648,7 @@
             * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
           * bitmanipulation
             * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
+            * [ClearLeftmostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java)
             * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
             * [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
             * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
@@ -905,6 +908,7 @@
             * [HeronsFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java)
             * [JosephusProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/JosephusProblemTest.java)
             * [KaprekarNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java)
+            * [KaratsubaMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java)
             * [LeastCommonMultipleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java)
             * [LeonardoNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java)
             * [LiouvilleLambdaFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java)
@@ -989,6 +993,7 @@
             * [RemoveDuplicateFromStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java)
             * [ReverseStackUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
             * [SkylineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
+            * [SudokuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SudokuTest.java)
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java b/src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java
new file mode 100644
index 000000000000..3e9a4a21183f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java
@@ -0,0 +1,39 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * ClearLeftmostSetBit class contains a method to clear the leftmost set bit of a number.
+ * The leftmost set bit is the leftmost bit that is set to 1 in the binary representation of a number.
+ *
+ * Example:
+ * 26 (11010) -> 10 (01010)
+ * 1 (1) -> 0 (0)
+ * 7 (111) -> 3 (011)
+ * 6 (0110) -> 2 (0010)
+ *
+ * @author Hardvan
+ */
+public final class ClearLeftmostSetBit {
+    private ClearLeftmostSetBit() {
+    }
+
+    /**
+     * Clears the leftmost set bit (1) of a given number.
+     * Step 1: Find the position of the leftmost set bit
+     * Step 2: Create a mask with all bits set except for the leftmost set bit
+     * Step 3: Clear the leftmost set bit using AND with the mask
+     *
+     * @param num The input number.
+     * @return The number after clearing the leftmost set bit.
+     */
+    public static int clearLeftmostSetBit(int num) {
+        int pos = 0;
+        int temp = num;
+        while (temp > 0) {
+            temp >>= 1;
+            pos++;
+        }
+
+        int mask = ~(1 << (pos - 1));
+        return num & mask;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java b/src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java
new file mode 100644
index 000000000000..e77889fb7b0a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java
@@ -0,0 +1,16 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class ClearLeftmostSetBitTest {
+
+    @Test
+    public void testClearLeftmostSetBit() {
+        assertEquals(10, ClearLeftmostSetBit.clearLeftmostSetBit(26)); // 11010 -> 01010
+        assertEquals(0, ClearLeftmostSetBit.clearLeftmostSetBit(1)); // 1 -> 0
+        assertEquals(3, ClearLeftmostSetBit.clearLeftmostSetBit(7)); // 111 -> 011
+        assertEquals(2, ClearLeftmostSetBit.clearLeftmostSetBit(6)); // 0110 -> 0010
+    }
+}

From b8633ad14c3b7f638d9f71a19713b9bcdef699ad Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 12 Oct 2024 11:49:55 +0530
Subject: [PATCH 0515/1338] feat: Add `countLeadingZeros` new algorithm with
 Junit tests (#5703)

---
 DIRECTORY.md                                  |  2 +
 .../bitmanipulation/CountLeadingZeros.java    | 39 +++++++++++++++++++
 .../CountLeadingZerosTest.java                | 16 ++++++++
 3 files changed, 57 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 51af99583ed7..1ecacc3c395e 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -25,6 +25,7 @@
           * bitmanipulation
             * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
             * [ClearLeftmostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java)
+            * [CountLeadingZeros](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java)
             * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
             * [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
             * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
@@ -649,6 +650,7 @@
           * bitmanipulation
             * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
             * [ClearLeftmostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java)
+            * [CountLeadingZerosTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java)
             * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
             * [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
             * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java b/src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java
new file mode 100644
index 000000000000..318334f0b951
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java
@@ -0,0 +1,39 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * CountLeadingZeros class contains a method to count the number of leading zeros in the binary representation of a number.
+ * The number of leading zeros is the number of zeros before the leftmost 1 bit.
+ * For example, the number 5 has 29 leading zeros in its 32-bit binary representation.
+ * The number 0 has 32 leading zeros.
+ * The number 1 has 31 leading zeros.
+ * The number -1 has no leading zeros.
+ *
+ * @author Hardvan
+ */
+public final class CountLeadingZeros {
+    private CountLeadingZeros() {
+    }
+
+    /**
+     * Counts the number of leading zeros in the binary representation of a number.
+     * Method: Keep shifting the mask to the right until the leftmost bit is 1.
+     * The number of shifts is the number of leading zeros.
+     *
+     * @param num The input number.
+     * @return The number of leading zeros.
+     */
+    public static int countLeadingZeros(int num) {
+        if (num == 0) {
+            return 32;
+        }
+
+        int count = 0;
+        int mask = 1 << 31;
+        while ((mask & num) == 0) {
+            count++;
+            mask >>>= 1;
+        }
+
+        return count;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java b/src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java
new file mode 100644
index 000000000000..6ab15fd2ab5a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java
@@ -0,0 +1,16 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class CountLeadingZerosTest {
+
+    @Test
+    public void testCountLeadingZeros() {
+        assertEquals(29, CountLeadingZeros.countLeadingZeros(5)); // 000...0101 has 29 leading zeros
+        assertEquals(32, CountLeadingZeros.countLeadingZeros(0)); // 000...0000 has 32 leading zeros
+        assertEquals(31, CountLeadingZeros.countLeadingZeros(1)); // 000...0001 has 31 leading zeros
+        assertEquals(0, CountLeadingZeros.countLeadingZeros(-1)); // No leading zeros in negative number (-1)
+    }
+}

From c0ffbb0e45f89c7d29c1955add9af81599c6530e Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 12 Oct 2024 11:56:04 +0530
Subject: [PATCH 0516/1338] Add `GrayCodeConversion` algorithm (#5705)

---
 DIRECTORY.md                                  |  2 +
 .../bitmanipulation/GrayCodeConversion.java   | 44 +++++++++++++++++++
 .../GrayCodeConversionTest.java               | 29 ++++++++++++
 3 files changed, 75 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 1ecacc3c395e..ebbb8ddc3110 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -27,6 +27,7 @@
             * [ClearLeftmostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java)
             * [CountLeadingZeros](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java)
             * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
+            * [GrayCodeConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java)
             * [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
             * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
             * [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
@@ -652,6 +653,7 @@
             * [ClearLeftmostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java)
             * [CountLeadingZerosTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java)
             * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
+            * [GrayCodeConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java)
             * [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
             * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
             * [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java b/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java
new file mode 100644
index 000000000000..83cd30c7d50a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * Gray code is a binary numeral system where two successive values differ in only one bit.
+ * This is a simple conversion between binary and Gray code.
+ * Example:
+ * 7 -> 0111 -> 0100 -> 4
+ * 4 -> 0100 -> 0111 -> 7
+ * 0 -> 0000 -> 0000 -> 0
+ * 1 -> 0001 -> 0000 -> 0
+ * 2 -> 0010 -> 0011 -> 3
+ * 3 -> 0011 -> 0010 -> 2
+ *
+ * @author Hardvan
+ */
+public final class GrayCodeConversion {
+    private GrayCodeConversion() {
+    }
+
+    /**
+     * Converts a binary number to Gray code.
+     *
+     * @param num The binary number.
+     * @return The corresponding Gray code.
+     */
+    public static int binaryToGray(int num) {
+        return num ^ (num >> 1);
+    }
+
+    /**
+     * Converts a Gray code number back to binary.
+     *
+     * @param gray The Gray code number.
+     * @return The corresponding binary number.
+     */
+    public static int grayToBinary(int gray) {
+        int binary = gray;
+        while (gray > 0) {
+            gray >>= 1;
+            binary ^= gray;
+        }
+        return binary;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java b/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java
new file mode 100644
index 000000000000..1fe792028dca
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class GrayCodeConversionTest {
+
+    @Test
+    public void testBinaryToGray() {
+        assertEquals(7, GrayCodeConversion.binaryToGray(5)); // 101 -> 111
+        assertEquals(4, GrayCodeConversion.binaryToGray(7)); // 111 -> 100
+        assertEquals(1, GrayCodeConversion.binaryToGray(1)); // 001 -> 001
+    }
+
+    @Test
+    public void testGrayToBinary() {
+        assertEquals(5, GrayCodeConversion.grayToBinary(7)); // 111 -> 101
+        assertEquals(4, GrayCodeConversion.grayToBinary(6)); // 110 -> 100
+        assertEquals(1, GrayCodeConversion.grayToBinary(1)); // 001 -> 001
+    }
+
+    @Test
+    public void testBinaryGrayCycle() {
+        int binary = 9; // 1001 in binary
+        int gray = GrayCodeConversion.binaryToGray(binary);
+        assertEquals(binary, GrayCodeConversion.grayToBinary(gray)); // Should return to original binary
+    }
+}

From bf0377f44b737f090aea99fd350dbf982a279884 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 12 Oct 2024 12:01:04 +0530
Subject: [PATCH 0517/1338] Add `HammingDistance` algorithm (#5706)

---
 DIRECTORY.md                                  |  2 ++
 .../bitmanipulation/HammingDistance.java      | 29 +++++++++++++++++++
 .../bitmanipulation/HammingDistanceTest.java  | 17 +++++++++++
 3 files changed, 48 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index ebbb8ddc3110..3692b436a353 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -28,6 +28,7 @@
             * [CountLeadingZeros](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java)
             * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
             * [GrayCodeConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java)
+            * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java)
             * [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
             * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
             * [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
@@ -654,6 +655,7 @@
             * [CountLeadingZerosTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java)
             * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
             * [GrayCodeConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java)
+            * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java)
             * [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
             * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
             * [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java b/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java
new file mode 100644
index 000000000000..4c24909ef234
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * The Hamming distance between two integers is the number of positions at which the corresponding bits are different.
+ * Given two integers x and y, calculate the Hamming distance.
+ * Example:
+ * Input: x = 1, y = 4
+ * Output: 2
+ * Explanation: 1 (0001) and 4 (0100) have 2 differing bits.
+ *
+ * @author Hardvan
+ */
+public final class HammingDistance {
+    private HammingDistance() {
+    }
+
+    /**
+     * Calculates the Hamming distance between two integers.
+     * The Hamming distance is the number of differing bits between the two integers.
+     *
+     * @param x The first integer.
+     * @param y The second integer.
+     * @return The Hamming distance (number of differing bits).
+     */
+    public static int hammingDistance(int x, int y) {
+        int xor = x ^ y;
+        return Integer.bitCount(xor);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java b/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java
new file mode 100644
index 000000000000..bde39a69f190
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java
@@ -0,0 +1,17 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class HammingDistanceTest {
+
+    @Test
+    public void testHammingDistance() {
+        assertEquals(3, HammingDistance.hammingDistance(9, 14)); // 1001 vs 1110, Hamming distance is 3
+        assertEquals(0, HammingDistance.hammingDistance(10, 10)); // Same number, Hamming distance is 0
+        assertEquals(1, HammingDistance.hammingDistance(1, 0)); // 0001 vs 0000, Hamming distance is 1
+        assertEquals(2, HammingDistance.hammingDistance(4, 1)); // 100 vs 001, Hamming distance is 2
+        assertEquals(4, HammingDistance.hammingDistance(0, 15)); // 0000 vs 1111, Hamming distance is 4
+    }
+}

From 4d6dd13b569082d348f19ec4b24a264f7fa2abb8 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 12 Oct 2024 12:06:29 +0530
Subject: [PATCH 0518/1338] Add `BinaryPalindromeCheck` algorithm (#5708)

---
 DIRECTORY.md                                  |  2 +
 .../BinaryPalindromeCheck.java                | 43 +++++++++++++++++++
 .../BinaryPalindromeCheckTest.java            | 18 ++++++++
 3 files changed, 63 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 3692b436a353..b62cde038651 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -23,6 +23,7 @@
             * [WordPatternMatcher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordPatternMatcher.java)
             * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
           * bitmanipulation
+            * [BinaryPalindromeCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java)
             * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
             * [ClearLeftmostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java)
             * [CountLeadingZeros](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java)
@@ -650,6 +651,7 @@
             * [WordPatternMatcherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordPatternMatcherTest.java)
             * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
           * bitmanipulation
+            * [BinaryPalindromeCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java)
             * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
             * [ClearLeftmostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java)
             * [CountLeadingZerosTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java b/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java
new file mode 100644
index 000000000000..0d6fd140c720
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java
@@ -0,0 +1,43 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class contains a method to check if the binary representation of a number is a palindrome.
+ * <p>
+ *     A binary palindrome is a number whose binary representation is the same when read from left to right and right to left.
+ *     For example, the number 9 has a binary representation of 1001, which is a palindrome.
+ *     The number 10 has a binary representation of 1010, which is not a palindrome.
+ * </p>
+ *
+ * @author Hardvan
+ */
+public final class BinaryPalindromeCheck {
+    private BinaryPalindromeCheck() {
+    }
+
+    /**
+     * Checks if the binary representation of a number is a palindrome.
+     *
+     * @param x The number to check.
+     * @return True if the binary representation is a palindrome, otherwise false.
+     */
+    public static boolean isBinaryPalindrome(int x) {
+        int reversed = reverseBits(x);
+        return x == reversed;
+    }
+
+    /**
+     * Helper function to reverse all the bits of an integer.
+     *
+     * @param x The number to reverse the bits of.
+     * @return The number with reversed bits.
+     */
+    private static int reverseBits(int x) {
+        int result = 0;
+        while (x > 0) {
+            result <<= 1;
+            result |= (x & 1);
+            x >>= 1;
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java b/src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java
new file mode 100644
index 000000000000..ff41344266e4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java
@@ -0,0 +1,18 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class BinaryPalindromeCheckTest {
+
+    @Test
+    public void testIsBinaryPalindrome() {
+        assertTrue(BinaryPalindromeCheck.isBinaryPalindrome(9)); // 1001 is a palindrome
+        assertFalse(BinaryPalindromeCheck.isBinaryPalindrome(10)); // 1010 is not a palindrome
+        assertTrue(BinaryPalindromeCheck.isBinaryPalindrome(0)); // 0 is a palindrome
+        assertTrue(BinaryPalindromeCheck.isBinaryPalindrome(1)); // 1 is a palindrome
+        assertFalse(BinaryPalindromeCheck.isBinaryPalindrome(12)); // 1100 is not a palindrome
+    }
+}

From eba6823c3ad8f81fac5ae1f4cc3de217063fd606 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 12 Oct 2024 12:15:28 +0530
Subject: [PATCH 0519/1338] Add `HigherLowerPowerOfTwo` algorithm (#5707)

---
 DIRECTORY.md                                  |  2 +
 .../HigherLowerPowerOfTwo.java                | 54 +++++++++++++++++++
 .../HigherLowerPowerOfTwoTest.java            | 26 +++++++++
 3 files changed, 82 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b62cde038651..880a5f12bdcc 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -30,6 +30,7 @@
             * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
             * [GrayCodeConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java)
             * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java)
+            * [HigherLowerPowerOfTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java)
             * [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
             * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
             * [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
@@ -658,6 +659,7 @@
             * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
             * [GrayCodeConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java)
             * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java)
+            * [HigherLowerPowerOfTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java)
             * [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
             * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
             * [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java b/src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java
new file mode 100644
index 000000000000..0fb058b2b8a3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * HigherLowerPowerOfTwo class has two methods to find the next higher and lower power of two.
+ * <p>
+ *     nextHigherPowerOfTwo method finds the next higher power of two.
+ *     nextLowerPowerOfTwo method finds the next lower power of two.
+ *     Both methods take an integer as input and return the next higher or lower power of two.
+ *     If the input is less than 1, the next higher power of two is 1.
+ *     If the input is less than or equal to 1, the next lower power of two is 0.
+ *     nextHigherPowerOfTwo method uses bitwise operations to find the next higher power of two.
+ *     nextLowerPowerOfTwo method uses Integer.highestOneBit method to find the next lower power of two.
+ *     The time complexity of both methods is O(1).
+ *     The space complexity of both methods is O(1).
+ * </p>
+ *
+ * @author Hardvan
+ */
+public final class HigherLowerPowerOfTwo {
+    private HigherLowerPowerOfTwo() {
+    }
+
+    /**
+     * Finds the next higher power of two.
+     *
+     * @param x The given number.
+     * @return The next higher power of two.
+     */
+    public static int nextHigherPowerOfTwo(int x) {
+        if (x < 1) {
+            return 1;
+        }
+        x--;
+        x |= x >> 1;
+        x |= x >> 2;
+        x |= x >> 4;
+        x |= x >> 8;
+        x |= x >> 16;
+        return x + 1;
+    }
+
+    /**
+     * Finds the next lower power of two.
+     *
+     * @param x The given number.
+     * @return The next lower power of two.
+     */
+    public static int nextLowerPowerOfTwo(int x) {
+        if (x < 1) {
+            return 0;
+        }
+        return Integer.highestOneBit(x);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java b/src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java
new file mode 100644
index 000000000000..34391002941b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java
@@ -0,0 +1,26 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class HigherLowerPowerOfTwoTest {
+
+    @Test
+    public void testNextHigherPowerOfTwo() {
+        assertEquals(32, HigherLowerPowerOfTwo.nextHigherPowerOfTwo(19)); // next higher power of two is 32
+        assertEquals(1, HigherLowerPowerOfTwo.nextHigherPowerOfTwo(1)); // next higher power of two is 1
+        assertEquals(16, HigherLowerPowerOfTwo.nextHigherPowerOfTwo(15)); // next higher power of two is 16
+        assertEquals(8, HigherLowerPowerOfTwo.nextHigherPowerOfTwo(8)); // next higher power of two is 8
+        assertEquals(16, HigherLowerPowerOfTwo.nextHigherPowerOfTwo(9)); // next higher power of two is 16
+    }
+
+    @Test
+    public void testNextLowerPowerOfTwo() {
+        assertEquals(16, HigherLowerPowerOfTwo.nextLowerPowerOfTwo(19)); // next lower power of two is 16
+        assertEquals(1, HigherLowerPowerOfTwo.nextLowerPowerOfTwo(1)); // next lower power of two is 1
+        assertEquals(8, HigherLowerPowerOfTwo.nextLowerPowerOfTwo(9)); // next lower power of two is 8
+        assertEquals(8, HigherLowerPowerOfTwo.nextLowerPowerOfTwo(15)); // next lower power of two is 8
+        assertEquals(8, HigherLowerPowerOfTwo.nextLowerPowerOfTwo(8)); // next lower power of two is 8
+    }
+}

From 138793df1d2681a554204c6fc2190348632567ec Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 12 Oct 2024 12:21:41 +0530
Subject: [PATCH 0520/1338] =?UTF-8?q?Improve=20docs,=20remove=20`main`,=20?=
 =?UTF-8?q?add=20tests=20for=20`MatrixChainRecursiveTopDo=E2=80=A6=20(#565?=
 =?UTF-8?q?9)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 DIRECTORY.md                                  |  1 +
 ...atrixChainRecursiveTopDownMemoisation.java | 46 +++++++++----
 ...xChainRecursiveTopDownMemoisationTest.java | 68 +++++++++++++++++++
 3 files changed, 102 insertions(+), 13 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisationTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 880a5f12bdcc..751141eb8d1c 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -836,6 +836,7 @@
             * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java)
             * [LongestValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java)
             * [MatrixChainMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplicationTest.java)
+            * [MatrixChainRecursiveTopDownMemoisationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisationTest.java)
             * [MaximumSumOfNonAdjacentElementsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElementsTest.java)
             * [MinimumPathSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java)
             * [MinimumSumPartitionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java
index 6c1c4cf54ffc..0c1031c6805c 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java
@@ -1,15 +1,31 @@
 package com.thealgorithms.dynamicprogramming;
 
-// Matrix-chain Multiplication
-// Problem Statement
-// we have given a chain A1,A2,...,Ani of n matrices, where for i = 1,2,...,n,
-// matrix Ai has dimension pi−1 ×pi
-// , fully parenthesize the product A1A2 ···An in a way that
-// minimizes the number of scalar multiplications.
+/**
+ * The MatrixChainRecursiveTopDownMemoisation class implements the matrix-chain
+ * multiplication problem using a top-down recursive approach with memoization.
+ *
+ * <p>Given a chain of matrices A1, A2, ..., An, where matrix Ai has dimensions
+ * pi-1 × pi, this algorithm finds the optimal way to fully parenthesize the
+ * product A1A2...An in a way that minimizes the total number of scalar
+ * multiplications required.</p>
+ *
+ * <p>This implementation uses a memoization technique to store the results of
+ * subproblems, which significantly reduces the number of recursive calls and
+ * improves performance compared to a naive recursive approach.</p>
+ */
 public final class MatrixChainRecursiveTopDownMemoisation {
     private MatrixChainRecursiveTopDownMemoisation() {
     }
 
+    /**
+     * Calculates the minimum number of scalar multiplications needed to multiply
+     * a chain of matrices.
+     *
+     * @param p an array of integers representing the dimensions of the matrices.
+     *          The length of the array is n + 1, where n is the number of matrices.
+     * @return the minimum number of multiplications required to multiply the chain
+     *         of matrices.
+     */
     static int memoizedMatrixChain(int[] p) {
         int n = p.length;
         int[][] m = new int[n][n];
@@ -21,6 +37,17 @@ static int memoizedMatrixChain(int[] p) {
         return lookupChain(m, p, 1, n - 1);
     }
 
+    /**
+     * A recursive helper method to lookup the minimum number of multiplications
+     * for multiplying matrices from index i to index j.
+     *
+     * @param m the memoization table storing the results of subproblems.
+     * @param p an array of integers representing the dimensions of the matrices.
+     * @param i the starting index of the matrix chain.
+     * @param j the ending index of the matrix chain.
+     * @return the minimum number of multiplications needed to multiply matrices
+     *         from i to j.
+     */
     static int lookupChain(int[][] m, int[] p, int i, int j) {
         if (i == j) {
             m[i][j] = 0;
@@ -38,11 +65,4 @@ static int lookupChain(int[][] m, int[] p, int i, int j) {
         }
         return m[i][j];
     }
-
-    // in this code we are taking the example of 4 matrixes whose orders are 1x2,2x3,3x4,4x5
-    // respectively output should be  Minimum number of multiplications is 38
-    public static void main(String[] args) {
-        int[] arr = {1, 2, 3, 4, 5};
-        System.out.println("Minimum number of multiplications is " + memoizedMatrixChain(arr));
-    }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisationTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisationTest.java
new file mode 100644
index 000000000000..f8270f6d50b5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisationTest.java
@@ -0,0 +1,68 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class MatrixChainRecursiveTopDownMemoisationTest {
+
+    /**
+     * Test case for four matrices with dimensions 1x2, 2x3, 3x4, and 4x5.
+     * The expected minimum number of multiplications is 38.
+     */
+    @Test
+    void testFourMatrices() {
+        int[] dimensions = {1, 2, 3, 4, 5};
+        int expected = 38;
+        int actual = MatrixChainRecursiveTopDownMemoisation.memoizedMatrixChain(dimensions);
+        assertEquals(expected, actual, "The minimum number of multiplications should be 38.");
+    }
+
+    /**
+     * Test case for three matrices with dimensions 10x20, 20x30, and 30x40.
+     * The expected minimum number of multiplications is 6000.
+     */
+    @Test
+    void testThreeMatrices() {
+        int[] dimensions = {10, 20, 30, 40};
+        int expected = 18000;
+        int actual = MatrixChainRecursiveTopDownMemoisation.memoizedMatrixChain(dimensions);
+        assertEquals(expected, actual, "The minimum number of multiplications should be 18000.");
+    }
+
+    /**
+     * Test case for two matrices with dimensions 5x10 and 10x20.
+     * The expected minimum number of multiplications is 1000.
+     */
+    @Test
+    void testTwoMatrices() {
+        int[] dimensions = {5, 10, 20};
+        int expected = 1000;
+        int actual = MatrixChainRecursiveTopDownMemoisation.memoizedMatrixChain(dimensions);
+        assertEquals(expected, actual, "The minimum number of multiplications should be 1000.");
+    }
+
+    /**
+     * Test case for a single matrix.
+     * The expected minimum number of multiplications is 0, as there are no multiplications needed.
+     */
+    @Test
+    void testSingleMatrix() {
+        int[] dimensions = {10, 20}; // Single matrix dimensions
+        int expected = 0;
+        int actual = MatrixChainRecursiveTopDownMemoisation.memoizedMatrixChain(dimensions);
+        assertEquals(expected, actual, "The minimum number of multiplications should be 0.");
+    }
+
+    /**
+     * Test case for matrices with varying dimensions.
+     * The expected minimum number of multiplications is calculated based on the dimensions provided.
+     */
+    @Test
+    void testVaryingDimensions() {
+        int[] dimensions = {2, 3, 4, 5, 6}; // Dimensions for 4 matrices
+        int expected = 124; // Expected value needs to be calculated based on the problem
+        int actual = MatrixChainRecursiveTopDownMemoisation.memoizedMatrixChain(dimensions);
+        assertEquals(expected, actual, "The minimum number of multiplications should be 124.");
+    }
+}

From b81671e66d2f87d1d704f550b0387d1436bf8715 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 12 Oct 2024 12:34:54 +0530
Subject: [PATCH 0521/1338] Add tests, remove `main` in `LowerBound` (#5672)

---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/searches/LowerBound.java    | 25 --------
 .../searches/LowerBoundTest.java              | 59 +++++++++++++++++++
 3 files changed, 60 insertions(+), 25 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/searches/LowerBoundTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 751141eb8d1c..dea06ca10f4f 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1036,6 +1036,7 @@
             * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
             * [LinearSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/LinearSearchTest.java)
             * [LinearSearchThreadTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java)
+            * [LowerBoundTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/LowerBoundTest.java)
             * [MonteCarloTreeSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/MonteCarloTreeSearchTest.java)
             * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
             * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
diff --git a/src/main/java/com/thealgorithms/searches/LowerBound.java b/src/main/java/com/thealgorithms/searches/LowerBound.java
index ee6f51e637f2..5a1401edd3c2 100644
--- a/src/main/java/com/thealgorithms/searches/LowerBound.java
+++ b/src/main/java/com/thealgorithms/searches/LowerBound.java
@@ -1,9 +1,6 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
-import java.util.Random;
-import java.util.concurrent.ThreadLocalRandom;
-import java.util.stream.IntStream;
 
 /**
  * The LowerBound method is used to return an index pointing to the first
@@ -25,28 +22,6 @@
  */
 class LowerBound implements SearchAlgorithm {
 
-    // Driver Program
-    public static void main(String[] args) {
-        // Just generate data
-        Random r = ThreadLocalRandom.current();
-
-        int size = 100;
-        int maxElement = 100000;
-
-        Integer[] integers = IntStream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().boxed().toArray(Integer[] ::new);
-
-        // The element for which the lower bound is to be found
-        int val = integers[r.nextInt(size - 1)] + 1;
-
-        LowerBound search = new LowerBound();
-        int atIndex = search.find(integers, val);
-
-        System.out.printf("Val: %d. Lower Bound Found %d at index %d. An array length %d%n", val, integers[atIndex], atIndex, size);
-
-        boolean toCheck = integers[atIndex] >= val || integers[size - 1] < val;
-        System.out.printf("Lower Bound found at an index: %d. Is greater or max element: %b%n", atIndex, toCheck);
-    }
-
     /**
      * @param array is an array where the LowerBound value is to be found
      * @param key is an element for which the LowerBound is to be found
diff --git a/src/test/java/com/thealgorithms/searches/LowerBoundTest.java b/src/test/java/com/thealgorithms/searches/LowerBoundTest.java
new file mode 100644
index 000000000000..30f4a5cb257c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/LowerBoundTest.java
@@ -0,0 +1,59 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class LowerBoundTest {
+
+    /**
+     * Test finding the lower bound for an element present in the array.
+     */
+    @Test
+    void testLowerBoundElementPresent() {
+        Integer[] array = {1, 2, 3, 4, 5};
+        LowerBound lowerBound = new LowerBound();
+
+        // Test for a value that is present
+        assertEquals(2, lowerBound.find(array, 3), "Lower bound for 3 should be at index 2");
+        assertEquals(0, lowerBound.find(array, 1), "Lower bound for 1 should be at index 0");
+        assertEquals(4, lowerBound.find(array, 5), "Lower bound for 5 should be at index 4");
+    }
+
+    /**
+     * Test finding the lower bound for a value greater than the maximum element in the array.
+     */
+    @Test
+    void testLowerBoundElementGreaterThanMax() {
+        Integer[] array = {1, 2, 3, 4, 5};
+        LowerBound lowerBound = new LowerBound();
+
+        // Test for a value greater than the maximum
+        assertEquals(4, lowerBound.find(array, 6), "Lower bound for 6 should be at index 4");
+    }
+
+    /**
+     * Test finding the lower bound for a value less than the minimum element in the array.
+     */
+    @Test
+    void testLowerBoundElementLessThanMin() {
+        Integer[] array = {1, 2, 3, 4, 5};
+        LowerBound lowerBound = new LowerBound();
+
+        // Test for a value less than the minimum
+        assertEquals(0, lowerBound.find(array, 0), "Lower bound for 0 should be at index 0");
+    }
+
+    /**
+     * Test finding the lower bound for a non-existent value that falls between two elements.
+     */
+    @Test
+    void testLowerBoundNonExistentValue() {
+        Integer[] array = {1, 2, 3, 4, 5};
+        LowerBound lowerBound = new LowerBound();
+
+        // Test for a value that is not present
+        assertEquals(4, lowerBound.find(array, 7), "Lower bound for 7 should be at index 4");
+        assertEquals(0, lowerBound.find(array, 0), "Lower bound for 0 should be at index 0");
+    }
+}

From e38611e9db0fdf318ac8513709f75077c55f25e3 Mon Sep 17 00:00:00 2001
From: PANKAJ PATWAL <120747214+Chiefpatwal@users.noreply.github.com>
Date: Sat, 12 Oct 2024 12:41:25 +0530
Subject: [PATCH 0522/1338] Optimize and Format Knapsack Memoization Algorithm
 (#5685)

---
 .../dynamicprogramming/KnapsackMemoization.java   | 11 +++++------
 .../KnapsackMemoizationTest.java                  | 15 +++++++++++++++
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java b/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java
index 396efb1a7893..3501e302a6ef 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.dynamicprogramming;
 
+import java.util.Arrays;
+
 /**
  * Recursive Solution for 0-1 knapsack with memoization
  * This method is basically an extension to the recursive approach so that we
@@ -15,10 +17,8 @@ int knapSack(int capacity, int[] weights, int[] profits, int numOfItems) {
         int[][] dpTable = new int[numOfItems + 1][capacity + 1];
 
         // Loop to initially fill the table with -1
-        for (int i = 0; i < numOfItems + 1; i++) {
-            for (int j = 0; j < capacity + 1; j++) {
-                dpTable[i][j] = -1;
-            }
+        for (int[] table : dpTable) {
+            Arrays.fill(table, -1);
         }
 
         return solveKnapsackRecursive(capacity, weights, profits, numOfItems, dpTable);
@@ -38,7 +38,6 @@ int solveKnapsackRecursive(int capacity, int[] weights, int[] profits, int numOf
         if (weights[numOfItems - 1] > capacity) {
             // Store the value of function call stack in table
             dpTable[numOfItems][capacity] = solveKnapsackRecursive(capacity, weights, profits, numOfItems - 1, dpTable);
-            return dpTable[numOfItems][capacity];
         } else {
             // case 1. include the item, if it is less than the capacity
             final int includeCurrentItem = profits[numOfItems - 1] + solveKnapsackRecursive(capacity - weights[numOfItems - 1], weights, profits, numOfItems - 1, dpTable);
@@ -48,7 +47,7 @@ int solveKnapsackRecursive(int capacity, int[] weights, int[] profits, int numOf
 
             // Store the value of function call stack in table and return
             dpTable[numOfItems][capacity] = Math.max(includeCurrentItem, excludeCurrentItem);
-            return dpTable[numOfItems][capacity];
         }
+        return dpTable[numOfItems][capacity];
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java
index d220a2bb512e..3545eb2667ed 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java
@@ -31,4 +31,19 @@ void test3() {
         int capacity = 50;
         assertEquals(220, knapsackMemoization.knapSack(capacity, weight, value, weight.length));
     }
+
+    @Test
+    void test4() {
+        int[] weight = {1, 2, 3};
+        int[] value = {10, 20, 30};
+        int capacity = 0;
+        assertEquals(0, knapsackMemoization.knapSack(capacity, weight, value, weight.length));
+    }
+    @Test
+    void test5() {
+        int[] weight = {1, 2, 3, 8};
+        int[] value = {10, 20, 30, 40};
+        int capacity = 50;
+        assertEquals(100, knapsackMemoization.knapSack(capacity, weight, value, weight.length));
+    }
 }

From e263edcfe04dc70969ff4dcd3f8983a144ca2946 Mon Sep 17 00:00:00 2001
From: Sailok Chinta <sailokchinta2012@gmail.com>
Date: Sat, 12 Oct 2024 12:53:41 +0530
Subject: [PATCH 0523/1338] Add `QuadTree` data structure (#5681)

---
 DIRECTORY.md                                  |   1 +
 .../datastructures/trees/QuadTree.java        | 176 ++++++++++++++++++
 .../datastructures/trees/QuadTreeTest.java    |  58 ++++++
 3 files changed, 235 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/trees/QuadTree.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/QuadTreeTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index dea06ca10f4f..3dbd1519ff08 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -218,6 +218,7 @@
               * [PostOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java)
               * [PreOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java)
               * [PrintTopViewofTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java)
+              * [QuadTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/QuadTree.java)
               * [RedBlackBST](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java)
               * [SameTreesCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java)
               * [SegmentTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/QuadTree.java b/src/main/java/com/thealgorithms/datastructures/trees/QuadTree.java
new file mode 100644
index 000000000000..e0d255b1e784
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/trees/QuadTree.java
@@ -0,0 +1,176 @@
+package com.thealgorithms.datastructures.trees;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Point is a simple class that represents a point in 2D space.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Point_(geometry)">Point</a>
+ * @author <a href="https://github.com/sailok">Sailok Chinta</a>
+ */
+class Point {
+    public double x;
+    public double y;
+
+    Point(double x, double y) {
+        this.x = x;
+        this.y = y;
+    }
+}
+
+/**
+ * BoundingBox is a simple class that represents a bounding box in 2D space.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Bounding_box">Bounding Box</a>
+ * @author <a href="https://github.com/sailok">Sailok Chinta</a>
+ */
+class BoundingBox {
+    public Point center;
+    public double halfWidth;
+
+    BoundingBox(Point center, double halfWidth) {
+        this.center = center;
+        this.halfWidth = halfWidth;
+    }
+
+    /**
+     * Checks if the point is inside the bounding box
+     *
+     * @param point The point to check
+     * @return true if the point is inside the bounding box, false otherwise
+     */
+    public boolean containsPoint(Point point) {
+        return point.x >= center.x - halfWidth && point.x <= center.x + halfWidth && point.y >= center.y - halfWidth && point.y <= center.y + halfWidth;
+    }
+
+    /**
+     * Checks if the bounding box intersects with the other bounding box
+     *
+     * @param otherBoundingBox The other bounding box
+     * @return true if the bounding box intersects with the other bounding box, false otherwise
+     */
+    public boolean intersectsBoundingBox(BoundingBox otherBoundingBox) {
+        return otherBoundingBox.center.x - otherBoundingBox.halfWidth <= center.x + halfWidth && otherBoundingBox.center.x + otherBoundingBox.halfWidth >= center.x - halfWidth && otherBoundingBox.center.y - otherBoundingBox.halfWidth <= center.y + halfWidth
+            && otherBoundingBox.center.y + otherBoundingBox.halfWidth >= center.y - halfWidth;
+    }
+}
+
+/**
+ * QuadTree is a tree data structure that is used to store spatial information
+ * in an efficient way.
+ *
+ * This implementation is specific to Point QuadTrees
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Quadtree">Quad Tree</a>
+ * @author <a href="https://github.com/sailok">Sailok Chinta</a>
+ */
+public class QuadTree {
+    private final BoundingBox boundary;
+    private final int capacity;
+
+    private List<Point> pointList;
+    private boolean divided;
+    private QuadTree northWest;
+    private QuadTree northEast;
+    private QuadTree southWest;
+    private QuadTree southEast;
+
+    public QuadTree(BoundingBox boundary, int capacity) {
+        this.boundary = boundary;
+        this.capacity = capacity;
+
+        this.pointList = new ArrayList<>();
+        this.divided = false;
+        this.northWest = null;
+        this.northEast = null;
+        this.southWest = null;
+        this.southEast = null;
+    }
+
+    /**
+     * Inserts a point into the tree
+     *
+     * @param point The point to insert
+     * @return true if the point is successfully inserted, false otherwise
+     */
+    public boolean insert(Point point) {
+        if (point == null) {
+            return false;
+        }
+
+        // Ignore points that don't belong to this quad tree
+        if (!boundary.containsPoint(point)) {
+            return false;
+        }
+
+        // if the space is not already occupied, add it to the list
+        if (pointList.size() < capacity) {
+            pointList.add(point);
+            return true;
+        }
+
+        // if subdivision hasn't happened, divide the tree
+        if (!divided) {
+            subDivide();
+        }
+
+        // try to add the point in one of the four quadrants
+        if (northWest.insert(point)) {
+            return true;
+        }
+
+        if (northEast.insert(point)) {
+            return true;
+        }
+
+        if (southWest.insert(point)) {
+            return true;
+        }
+
+        if (southEast.insert(point)) {
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Create four children that fully divide this quad into four quads of equal area
+     */
+    private void subDivide() {
+        double quadrantHalfWidth = boundary.halfWidth / 2;
+
+        northWest = new QuadTree(new BoundingBox(new Point(boundary.center.x - quadrantHalfWidth, boundary.center.y + quadrantHalfWidth), quadrantHalfWidth), this.capacity);
+        northEast = new QuadTree(new BoundingBox(new Point(boundary.center.x + quadrantHalfWidth, boundary.center.y + quadrantHalfWidth), quadrantHalfWidth), this.capacity);
+        southWest = new QuadTree(new BoundingBox(new Point(boundary.center.x - quadrantHalfWidth, boundary.center.y - quadrantHalfWidth), quadrantHalfWidth), this.capacity);
+        southEast = new QuadTree(new BoundingBox(new Point(boundary.center.x + quadrantHalfWidth, boundary.center.y - quadrantHalfWidth), quadrantHalfWidth), this.capacity);
+        divided = true;
+    }
+
+    /**
+     * Queries all the points that intersect with the other bounding box
+     *
+     * @param otherBoundingBox The other bounding box
+     * @return List of points that intersect with the other bounding box
+     */
+    public List<Point> query(BoundingBox otherBoundingBox) {
+        List<Point> points = new ArrayList<>();
+
+        if (!boundary.intersectsBoundingBox(otherBoundingBox)) {
+            return points;
+        }
+
+        // filter the points that intersect with the other bounding box
+        points.addAll(pointList.stream().filter(otherBoundingBox::containsPoint).toList());
+
+        if (divided) {
+            points.addAll(northWest.query(otherBoundingBox));
+            points.addAll(northEast.query(otherBoundingBox));
+            points.addAll(southWest.query(otherBoundingBox));
+            points.addAll(southEast.query(otherBoundingBox));
+        }
+
+        return points;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/QuadTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/QuadTreeTest.java
new file mode 100644
index 000000000000..62b86da214db
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/QuadTreeTest.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.datastructures.trees;
+
+import java.util.List;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class QuadTreeTest {
+    int quadTreeCapacity = 4;
+    BoundingBox boundingBox = new BoundingBox(new Point(0, 0), 500);
+    QuadTree quadTree = new QuadTree(boundingBox, quadTreeCapacity);
+
+    @Test
+    public void testNullPointInsertIntoQuadTree() {
+        Assertions.assertFalse(quadTree.insert(null));
+    }
+
+    @Test
+    public void testInsertIntoQuadTree() {
+        Assertions.assertTrue(quadTree.insert(new Point(10, -10)));
+        Assertions.assertTrue(quadTree.insert(new Point(-10, 10)));
+        Assertions.assertTrue(quadTree.insert(new Point(-10, -10)));
+        Assertions.assertTrue(quadTree.insert(new Point(10, 10)));
+        Assertions.assertFalse(quadTree.insert(new Point(1050, 1050)));
+    }
+
+    @Test
+    public void testInsertIntoQuadTreeAndSubDivide() {
+        Assertions.assertTrue(quadTree.insert(new Point(10, -10)));
+        Assertions.assertTrue(quadTree.insert(new Point(-10, 10)));
+        Assertions.assertTrue(quadTree.insert(new Point(-10, -10)));
+        Assertions.assertTrue(quadTree.insert(new Point(10, 10)));
+        Assertions.assertTrue(quadTree.insert(new Point(-100, 100)));
+        Assertions.assertTrue(quadTree.insert(new Point(100, -101)));
+        Assertions.assertTrue(quadTree.insert(new Point(-100, -100)));
+        Assertions.assertTrue(quadTree.insert(new Point(100, 100)));
+    }
+
+    @Test
+    public void testQueryInQuadTree() {
+        quadTree.insert(new Point(10, -10));
+        quadTree.insert(new Point(-10, 10));
+        quadTree.insert(new Point(-10, -10));
+        quadTree.insert(new Point(10, 10));
+        quadTree.insert(new Point(-100, 100));
+        quadTree.insert(new Point(100, -100));
+        quadTree.insert(new Point(-100, -100));
+        quadTree.insert(new Point(100, 100));
+
+        List<Point> points = quadTree.query(new BoundingBox(new Point(0, 0), 100));
+        Assertions.assertEquals(8, points.size());
+
+        points = quadTree.query(new BoundingBox(new Point(5, 5), 5));
+        Assertions.assertEquals(1, points.size());
+
+        points = quadTree.query(new BoundingBox(new Point(-200, -200), 5));
+        Assertions.assertEquals(0, points.size());
+    }
+}

From 872259843487610e3a971bbefb83af425d7bdbe5 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 12 Oct 2024 12:58:42 +0530
Subject: [PATCH 0524/1338] Add `ParityCheck` algorithm (#5704)

---
 DIRECTORY.md                                  |  3 ++
 .../bitmanipulation/ParityCheck.java          | 34 +++++++++++++++++++
 .../bitmanipulation/ParityCheckTest.java      | 15 ++++++++
 3 files changed, 52 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/ParityCheck.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 3dbd1519ff08..30fa2cbee199 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -40,6 +40,7 @@
             * [NumberAppearingOddTimes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
             * [OnesComplement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java)
+            * [ParityCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ParityCheck.java)
             * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
             * [SingleBitOperations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java)
             * [SingleElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleElement.java)
@@ -670,6 +671,7 @@
             * [NumberAppearingOddTimesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
             * [OnesComplementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java)
+            * [ParityCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java)
             * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
             * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
             * [SingleElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleElementTest.java)
@@ -801,6 +803,7 @@
               * [LevelOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/LevelOrderTraversalTest.java)
               * [PostOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/PostOrderTraversalTest.java)
               * [PreOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/PreOrderTraversalTest.java)
+              * [QuadTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/QuadTreeTest.java)
               * [SameTreesCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SameTreesCheckTest.java)
               * [SplayTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java)
               * [TreapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/ParityCheck.java b/src/main/java/com/thealgorithms/bitmanipulation/ParityCheck.java
new file mode 100644
index 000000000000..5acab4d4a362
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/ParityCheck.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * The ParityCheck class provides a method to check the parity of a given number.
+ * <p>
+ * Parity is a mathematical term that describes the property of an integer's binary representation.
+ * The parity of a binary number is the number of 1s in its binary representation.
+ * If the number of 1s is even, the parity is even; otherwise, it is odd.
+ * <p>
+ * For example, the binary representation of 5 is 101, which has two 1s, so the parity of 5 is even.
+ * The binary representation of 6 is 110, which has two 1s, so the parity of 6 is even.
+ * The binary representation of 7 is 111, which has three 1s, so the parity of 7 is odd.
+ *
+ * @author Hardvan
+ */
+public final class ParityCheck {
+    private ParityCheck() {
+    }
+
+    /**
+     * This method checks the parity of the given number.
+     *
+     * @param n the number to check the parity of
+     * @return true if the number has even parity, false otherwise
+     */
+    public static boolean checkParity(int n) {
+        int count = 0;
+        while (n > 0) {
+            count += n & 1;
+            n >>= 1;
+        }
+        return count % 2 == 0;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java b/src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java
new file mode 100644
index 000000000000..90147a61207b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java
@@ -0,0 +1,15 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class ParityCheckTest {
+    @Test
+    public void testIsOddParity() {
+        assertTrue(ParityCheck.checkParity(5)); // 101 has 2 ones (even parity)
+        assertFalse(ParityCheck.checkParity(7)); // 111 has 3 ones (odd parity)
+        assertFalse(ParityCheck.checkParity(8)); // 1000 has 1 one (odd parity)
+    }
+}

From f8397bf09b3c7554da52470d6db3bf5b7b8d1e34 Mon Sep 17 00:00:00 2001
From: Benjamin Burstein <98127047+bennybebo@users.noreply.github.com>
Date: Sat, 12 Oct 2024 03:34:49 -0400
Subject: [PATCH 0525/1338] Add ADFGVX Cipher (#5631)

---
 .../thealgorithms/ciphers/ADFGVXCipher.java   | 123 ++++++++++++++++++
 .../ciphers/ADFGVXCipherTest.java             |  36 +++++
 2 files changed, 159 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java

diff --git a/src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java b/src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java
new file mode 100644
index 000000000000..3e62d6a26dcb
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java
@@ -0,0 +1,123 @@
+package com.thealgorithms.ciphers;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+/**
+ * The ADFGVX cipher is a historically significant cipher used by
+ * the German Army during World War I. It is a fractionating transposition
+ * cipher that combines a Polybius square substitution with a columnar
+ * transposition. It's named after the six letters (A, D, F, G, V, X)
+ * that it uses in its substitution process.
+ * https://en.wikipedia.org/wiki/ADFGVX_cipher
+ *
+ * @author bennybebo
+ */
+public class ADFGVXCipher {
+
+    private static final char[] POLYBIUS_LETTERS = {'A', 'D', 'F', 'G', 'V', 'X'};
+    private static final char[][] POLYBIUS_SQUARE = {{'N', 'A', '1', 'C', '3', 'H'}, {'8', 'T', 'B', '2', 'O', 'M'}, {'E', '5', 'W', 'R', 'P', 'D'}, {'4', 'F', '6', 'G', '7', 'I'}, {'9', 'J', '0', 'K', 'L', 'Q'}, {'S', 'U', 'V', 'X', 'Y', 'Z'}};
+    private static final Map<String, Character> POLYBIUS_MAP = new HashMap<>();
+    private static final Map<Character, String> REVERSE_POLYBIUS_MAP = new HashMap<>();
+
+    static {
+        for (int i = 0; i < POLYBIUS_SQUARE.length; i++) {
+            for (int j = 0; j < POLYBIUS_SQUARE[i].length; j++) {
+                String key = "" + POLYBIUS_LETTERS[i] + POLYBIUS_LETTERS[j];
+                POLYBIUS_MAP.put(key, POLYBIUS_SQUARE[i][j]);
+                REVERSE_POLYBIUS_MAP.put(POLYBIUS_SQUARE[i][j], key);
+            }
+        }
+    }
+
+    // Encrypts the plaintext using the ADFGVX cipher
+    public String encrypt(String plaintext, String key) {
+        plaintext = plaintext.toUpperCase().replaceAll("[^A-Z0-9]", "");
+        StringBuilder fractionatedText = new StringBuilder();
+
+        // Step 1: Polybius square substitution
+        for (char c : plaintext.toCharArray()) {
+            fractionatedText.append(REVERSE_POLYBIUS_MAP.get(c));
+        }
+
+        // Step 2: Columnar transposition
+        return columnarTransposition(fractionatedText.toString(), key);
+    }
+
+    // Decrypts the ciphertext using the ADFGVX cipher
+    public String decrypt(String ciphertext, String key) {
+        // Step 1: Reverse the columnar transposition
+        String fractionatedText = reverseColumnarTransposition(ciphertext, key);
+
+        // Step 2: Polybius square substitution
+        StringBuilder plaintext = new StringBuilder();
+        for (int i = 0; i < fractionatedText.length(); i += 2) {
+            String pair = fractionatedText.substring(i, i + 2);
+            plaintext.append(POLYBIUS_MAP.get(pair));
+        }
+
+        return plaintext.toString();
+    }
+
+    private String columnarTransposition(String text, String key) {
+        int numRows = (int) Math.ceil((double) text.length() / key.length());
+        char[][] table = new char[numRows][key.length()];
+        for (char[] row : table) {
+            Arrays.fill(row, '_'); // Fill with underscores to handle empty cells
+        }
+
+        // Fill the table row by row
+        for (int i = 0; i < text.length(); i++) {
+            table[i / key.length()][i % key.length()] = text.charAt(i);
+        }
+
+        // Read columns based on the alphabetical order of the key
+        StringBuilder ciphertext = new StringBuilder();
+        char[] sortedKey = key.toCharArray();
+        Arrays.sort(sortedKey);
+
+        for (char keyChar : sortedKey) {
+            int column = key.indexOf(keyChar);
+            for (char[] row : table) {
+                if (row[column] != '_') {
+                    ciphertext.append(row[column]);
+                }
+            }
+        }
+
+        return ciphertext.toString();
+    }
+
+    private String reverseColumnarTransposition(String ciphertext, String key) {
+        int numRows = (int) Math.ceil((double) ciphertext.length() / key.length());
+        char[][] table = new char[numRows][key.length()];
+
+        char[] sortedKey = key.toCharArray();
+        Arrays.sort(sortedKey);
+
+        int index = 0;
+        // Fill the table column by column according to the sorted key order
+        for (char keyChar : sortedKey) {
+            int column = key.indexOf(keyChar);
+            for (int row = 0; row < numRows; row++) {
+                if (index < ciphertext.length()) {
+                    table[row][column] = ciphertext.charAt(index++);
+                } else {
+                    table[row][column] = '_'; // Fill empty cells with an underscore
+                }
+            }
+        }
+
+        // Read the table row by row to get the fractionated text
+        StringBuilder fractionatedText = new StringBuilder();
+        for (char[] row : table) {
+            for (char cell : row) {
+                if (cell != '_') {
+                    fractionatedText.append(cell);
+                }
+            }
+        }
+
+        return fractionatedText.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java b/src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java
new file mode 100644
index 000000000000..a1fc4fd9ebe5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class ADFGVXCipherTest {
+
+    ADFGVXCipher adfgvxCipher = new ADFGVXCipher();
+
+    @Test
+    void adfgvxCipherEncryptTest() {
+        // given
+        String message = "attack at 1200am"; // Plaintext message
+        String keyword = "PRIVACY";
+
+        // when
+        String cipherText = adfgvxCipher.encrypt(message, keyword);
+
+        // then
+        assertEquals("DGDDDAGDDGAFADDFDADVDVFAADVX", cipherText);
+    }
+
+    @Test
+    void adfgvxCipherDecryptTest() {
+        // given
+        String cipherText = "DGDDDAGDDGAFADDFDADVDVFAADVX"; // Ciphertext message
+        String keyword = "PRIVACY";
+
+        // when
+        String plainText = adfgvxCipher.decrypt(cipherText, keyword);
+
+        // then
+        assertEquals("ATTACKAT1200AM", plainText);
+    }
+}

From 31de2db0ae282054b81695e322dccb1baa3a32a1 Mon Sep 17 00:00:00 2001
From: Saahil Mahato <115351000+saahil-mahato@users.noreply.github.com>
Date: Sat, 12 Oct 2024 13:24:05 +0545
Subject: [PATCH 0526/1338] Add fast exponentiation algorithm (#5715)

---
 .../maths/FastExponentiation.java             | 67 +++++++++++++++++++
 .../maths/FastExponentiationTest.java         | 67 +++++++++++++++++++
 2 files changed, 134 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/FastExponentiation.java
 create mode 100644 src/test/java/com/thealgorithms/maths/FastExponentiationTest.java

diff --git a/src/main/java/com/thealgorithms/maths/FastExponentiation.java b/src/main/java/com/thealgorithms/maths/FastExponentiation.java
new file mode 100644
index 000000000000..27f49e27ff30
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/FastExponentiation.java
@@ -0,0 +1,67 @@
+package com.thealgorithms.maths;
+
+/**
+ * This class provides a method to perform fast exponentiation (exponentiation by squaring),
+ * which calculates (base^exp) % mod efficiently.
+ *
+ * <p>The algorithm works by repeatedly squaring the base and reducing the exponent
+ * by half at each step. It exploits the fact that:
+ * <ul>
+ *   <li>If exp is even, (base^exp) = (base^(exp/2))^2</li>
+ *   <li>If exp is odd, (base^exp) = base * (base^(exp-1))</li>
+ * </ul>
+ * The result is computed modulo `mod` at each step to avoid overflow and keep the result within bounds.
+ * </p>
+ *
+ * <p><strong>Time complexity:</strong> O(log(exp)) — much faster than naive exponentiation (O(exp)).</p>
+ *
+ * For more information, please visit {@link https://en.wikipedia.org/wiki/Exponentiation_by_squaring}
+ */
+public final class FastExponentiation {
+
+    /**
+     * Private constructor to hide the implicit public one.
+     */
+    private FastExponentiation() {
+    }
+
+    /**
+     * Performs fast exponentiation to calculate (base^exp) % mod using the method
+     * of exponentiation by squaring.
+     *
+     * <p>This method efficiently computes the result by squaring the base and halving
+     * the exponent at each step. It multiplies the base to the result when the exponent is odd.
+     *
+     * @param base the base number to be raised to the power of exp
+     * @param exp the exponent to which the base is raised
+     * @param mod the modulus to ensure the result does not overflow
+     * @return (base^exp) % mod
+     * @throws IllegalArgumentException if the modulus is less than or equal to 0
+     * @throws ArithmeticException if the exponent is negative (not supported in this implementation)
+     */
+    public static long fastExponentiation(long base, long exp, long mod) {
+        if (mod <= 0) {
+            throw new IllegalArgumentException("Modulus must be positive.");
+        }
+
+        if (exp < 0) {
+            throw new ArithmeticException("Negative exponent is not supported.");
+        }
+
+        long result = 1;
+        base = base % mod; // Take the modulus of the base to handle large base values
+
+        // Fast exponentiation by squaring algorithm
+        while (exp > 0) {
+            // If exp is odd, multiply the base to the result
+            if ((exp & 1) == 1) { // exp & 1 checks if exp is odd
+                result = result * base % mod;
+            }
+            // Square the base and halve the exponent
+            base = base * base % mod; // base^2 % mod to avoid overflow
+            exp >>= 1; // Right shift exp to divide it by 2
+        }
+
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/FastExponentiationTest.java b/src/test/java/com/thealgorithms/maths/FastExponentiationTest.java
new file mode 100644
index 000000000000..f117f90233e3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/FastExponentiationTest.java
@@ -0,0 +1,67 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the {@link FastExponentiation} class.
+ *
+ * <p>This class contains various test cases to verify the correctness of the fastExponentiation method.
+ * It covers basic functionality, edge cases, and exceptional cases.
+ */
+class FastExponentiationTest {
+
+    /**
+     * Tests fast exponentiation with small numbers.
+     */
+    @Test
+    void testSmallNumbers() {
+        assertEquals(1024, FastExponentiation.fastExponentiation(2, 10, 10000), "2^10 mod 10000 should be 1024");
+        assertEquals(81, FastExponentiation.fastExponentiation(3, 4, 1000), "3^4 mod 1000 should be 81");
+    }
+
+    /**
+     * Tests the behavior of the fast exponentiation method when using a modulus.
+     */
+    @Test
+    void testWithModulo() {
+        assertEquals(24, FastExponentiation.fastExponentiation(2, 10, 1000), "2^10 mod 1000 should be 24");
+        assertEquals(0, FastExponentiation.fastExponentiation(10, 5, 10), "10^5 mod 10 should be 0");
+    }
+
+    /**
+     * Tests the edge cases where base or exponent is 0.
+     */
+    @Test
+    void testBaseCases() {
+        assertEquals(1, FastExponentiation.fastExponentiation(2, 0, 1000), "Any number raised to the power 0 mod anything should be 1");
+        assertEquals(0, FastExponentiation.fastExponentiation(0, 10, 1000), "0 raised to any power should be 0");
+        assertEquals(1, FastExponentiation.fastExponentiation(0, 0, 1000), "0^0 is considered 0 in modular arithmetic.");
+    }
+
+    /**
+     * Tests fast exponentiation with a negative base to ensure correctness under modular arithmetic.
+     */
+    @Test
+    void testNegativeBase() {
+        assertEquals(9765625, FastExponentiation.fastExponentiation(-5, 10, 1000000007), "-5^10 mod 1000000007 should be 9765625");
+    }
+
+    /**
+     * Tests that a negative exponent throws an ArithmeticException.
+     */
+    @Test
+    void testNegativeExponent() {
+        assertThrows(ArithmeticException.class, () -> { FastExponentiation.fastExponentiation(2, -5, 1000); });
+    }
+
+    /**
+     * Tests that the method throws an IllegalArgumentException for invalid modulus values.
+     */
+    @Test
+    void testInvalidModulus() {
+        assertThrows(IllegalArgumentException.class, () -> { FastExponentiation.fastExponentiation(2, 5, 0); });
+    }
+}

From ac65af44c9365d42da42fb71c0b76115677fc673 Mon Sep 17 00:00:00 2001
From: Saahil Mahato <115351000+saahil-mahato@users.noreply.github.com>
Date: Sat, 12 Oct 2024 13:29:41 +0545
Subject: [PATCH 0527/1338] Add Johnson's algorithm (#5712)

---
 .../graphs/JohnsonsAlgorithm.java             | 203 ++++++++++++++++++
 .../graphs/JohnsonsAlgorithmTest.java         | 136 ++++++++++++
 2 files changed, 339 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java
new file mode 100644
index 000000000000..76c11f782985
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java
@@ -0,0 +1,203 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * This class implements Johnson's algorithm for finding all-pairs shortest paths in a weighted,
+ * directed graph that may contain negative edge weights.
+ *
+ * Johnson's algorithm works by using the Bellman-Ford algorithm to compute a transformation of the
+ * input graph that removes all negative weights, allowing Dijkstra's algorithm to be used for
+ * efficient shortest path computations.
+ *
+ * Time Complexity: O(V^2 * log(V) + V*E)
+ * Space Complexity: O(V^2)
+ *
+ * Where V is the number of vertices and E is the number of edges in the graph.
+ *
+ * For more information, please visit {@link https://en.wikipedia.org/wiki/Johnson%27s_algorithm}
+ */
+public final class JohnsonsAlgorithm {
+
+    // Constant representing infinity
+    private static final double INF = Double.POSITIVE_INFINITY;
+
+    /**
+     * A private constructor to hide the implicit public one.
+     */
+    private JohnsonsAlgorithm() {
+    }
+
+    /**
+     * Executes Johnson's algorithm on the given graph.
+     *
+     * @param graph The input graph represented as an adjacency matrix.
+     * @return A 2D array representing the shortest distances between all pairs of vertices.
+     */
+    public static double[][] johnsonAlgorithm(double[][] graph) {
+        int numVertices = graph.length;
+        double[][] edges = convertToEdgeList(graph);
+
+        // Step 1: Add a new vertex and run Bellman-Ford
+        double[] modifiedWeights = bellmanFord(edges, numVertices);
+
+        // Step 2: Reweight the graph
+        double[][] reweightedGraph = reweightGraph(graph, modifiedWeights);
+
+        // Step 3: Run Dijkstra's algorithm for each vertex
+        double[][] shortestDistances = new double[numVertices][numVertices];
+        for (int source = 0; source < numVertices; source++) {
+            shortestDistances[source] = dijkstra(reweightedGraph, source, modifiedWeights);
+        }
+
+        return shortestDistances;
+    }
+
+    /**
+     * Converts the adjacency matrix representation of the graph to an edge list.
+     *
+     * @param graph The input graph as an adjacency matrix.
+     * @return An array of edges, where each edge is represented as [from, to, weight].
+     */
+    public static double[][] convertToEdgeList(double[][] graph) {
+        int numVertices = graph.length;
+        List<double[]> edgeList = new ArrayList<>();
+
+        for (int i = 0; i < numVertices; i++) {
+            for (int j = 0; j < numVertices; j++) {
+                if (i != j && !Double.isInfinite(graph[i][j])) {
+                    // Only add edges that are not self-loops and have a finite weight
+                    edgeList.add(new double[] {i, j, graph[i][j]});
+                }
+            }
+        }
+
+        // Convert the List to a 2D array
+        return edgeList.toArray(new double[0][]);
+    }
+
+    /**
+     * Implements the Bellman-Ford algorithm to compute the shortest paths from a new vertex
+     * to all other vertices. This is used to calculate the weight function h(v) for reweighting.
+     *
+     * @param edges The edge list of the graph.
+     * @param numVertices The number of vertices in the original graph.
+     * @return An array of modified weights for each vertex.
+     */
+    private static double[] bellmanFord(double[][] edges, int numVertices) {
+        double[] dist = new double[numVertices + 1];
+        Arrays.fill(dist, INF);
+        dist[numVertices] = 0; // Distance to the new source vertex is 0
+
+        // Add edges from the new vertex to all original vertices
+        double[][] allEdges = Arrays.copyOf(edges, edges.length + numVertices);
+        for (int i = 0; i < numVertices; i++) {
+            allEdges[edges.length + i] = new double[] {numVertices, i, 0};
+        }
+
+        // Relax all edges V times
+        for (int i = 0; i < numVertices; i++) {
+            for (double[] edge : allEdges) {
+                int u = (int) edge[0];
+                int v = (int) edge[1];
+                double weight = edge[2];
+                if (dist[u] != INF && dist[u] + weight < dist[v]) {
+                    dist[v] = dist[u] + weight;
+                }
+            }
+        }
+
+        // Check for negative weight cycles
+        for (double[] edge : allEdges) {
+            int u = (int) edge[0];
+            int v = (int) edge[1];
+            double weight = edge[2];
+            if (dist[u] + weight < dist[v]) {
+                throw new IllegalArgumentException("Graph contains a negative weight cycle");
+            }
+        }
+
+        return Arrays.copyOf(dist, numVertices);
+    }
+
+    /**
+     * Reweights the graph using the modified weights computed by Bellman-Ford.
+     *
+     * @param graph The original graph.
+     * @param modifiedWeights The modified weights from Bellman-Ford.
+     * @return The reweighted graph.
+     */
+    public static double[][] reweightGraph(double[][] graph, double[] modifiedWeights) {
+        int numVertices = graph.length;
+        double[][] reweightedGraph = new double[numVertices][numVertices];
+
+        for (int i = 0; i < numVertices; i++) {
+            for (int j = 0; j < numVertices; j++) {
+                if (graph[i][j] != 0) {
+                    // New weight = original weight + h(u) - h(v)
+                    reweightedGraph[i][j] = graph[i][j] + modifiedWeights[i] - modifiedWeights[j];
+                }
+            }
+        }
+
+        return reweightedGraph;
+    }
+
+    /**
+     * Implements Dijkstra's algorithm for finding shortest paths from a source vertex.
+     *
+     * @param reweightedGraph The reweighted graph to run Dijkstra's on.
+     * @param source The source vertex.
+     * @param modifiedWeights The modified weights from Bellman-Ford.
+     * @return An array of shortest distances from the source to all other vertices.
+     */
+    public static double[] dijkstra(double[][] reweightedGraph, int source, double[] modifiedWeights) {
+        int numVertices = reweightedGraph.length;
+        double[] dist = new double[numVertices];
+        boolean[] visited = new boolean[numVertices];
+        Arrays.fill(dist, INF);
+        dist[source] = 0;
+
+        for (int count = 0; count < numVertices - 1; count++) {
+            int u = minDistance(dist, visited);
+            visited[u] = true;
+
+            for (int v = 0; v < numVertices; v++) {
+                if (!visited[v] && reweightedGraph[u][v] != 0 && dist[u] != INF && dist[u] + reweightedGraph[u][v] < dist[v]) {
+                    dist[v] = dist[u] + reweightedGraph[u][v];
+                }
+            }
+        }
+
+        // Adjust distances back to the original graph weights
+        for (int i = 0; i < numVertices; i++) {
+            if (dist[i] != INF) {
+                dist[i] = dist[i] - modifiedWeights[source] + modifiedWeights[i];
+            }
+        }
+
+        return dist;
+    }
+
+    /**
+     * Finds the vertex with the minimum distance value from the set of vertices
+     * not yet included in the shortest path tree.
+     *
+     * @param dist Array of distances.
+     * @param visited Array of visited vertices.
+     * @return The index of the vertex with minimum distance.
+     */
+    public static int minDistance(double[] dist, boolean[] visited) {
+        double min = INF;
+        int minIndex = -1;
+        for (int v = 0; v < dist.length; v++) {
+            if (!visited[v] && dist[v] <= min) {
+                min = dist[v];
+                minIndex = v;
+            }
+        }
+        return minIndex;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java
new file mode 100644
index 000000000000..0ae837cd944f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java
@@ -0,0 +1,136 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for {@link JohnsonsAlgorithm} class. This class
+ * contains test cases to verify the correct implementation of
+ * various methods used in Johnson's Algorithm such as shortest path
+ * calculations, graph reweighting, and more.
+ */
+class JohnsonsAlgorithmTest {
+
+    // Constant representing infinity
+    private static final double INF = Double.POSITIVE_INFINITY;
+
+    /**
+     * Tests the Johnson's Algorithm with a simple graph without negative edges.
+     * Verifies that the algorithm returns the correct shortest path distances.
+     */
+    @Test
+    void testSimpleGraph() {
+        // Test case for a simple graph without negative edges
+        double[][] graph = {{0, 4, INF, INF}, {INF, 0, 1, INF}, {INF, INF, 0, 2}, {INF, INF, INF, 0}};
+
+        double[][] result = JohnsonsAlgorithm.johnsonAlgorithm(graph);
+
+        double[][] expected = {{0, 4, 5, 7}, {INF, 0, 1, 3}, {INF, INF, 0, 2}, {INF, INF, INF, 0}};
+
+        assertArrayEquals(expected, result);
+    }
+
+    /**
+     * Tests Johnson's Algorithm on a graph with negative edges but no
+     * negative weight cycles. Verifies the algorithm handles negative
+     * edge weights correctly.
+     */
+    @Test
+    void testGraphWithNegativeEdges() {
+        // Graph with negative edges but no negative weight cycles
+        double[][] graph = {{0, -1, 4}, {INF, 0, 3}, {INF, INF, 0}};
+
+        double[][] result = JohnsonsAlgorithm.johnsonAlgorithm(graph);
+
+        double[][] expected = {{0, INF, 4}, {INF, 0, 3}, {INF, INF, 0}};
+
+        assertArrayEquals(expected, result);
+    }
+
+    /**
+     * Tests the behavior of Johnson's Algorithm on a graph with a negative
+     * weight cycle. Expects an IllegalArgumentException to be thrown
+     * due to the presence of the cycle.
+     */
+    @Test
+    void testNegativeWeightCycle() {
+        // Graph with a negative weight cycle
+        double[][] graph = {{0, 1, INF}, {INF, 0, -1}, {-1, INF, 0}};
+
+        // Johnson's algorithm should throw an exception when a negative cycle is detected
+        assertThrows(IllegalArgumentException.class, () -> { JohnsonsAlgorithm.johnsonAlgorithm(graph); });
+    }
+
+    /**
+     * Tests Dijkstra's algorithm as a part of Johnson's algorithm implementation
+     * on a small graph. Verifies that the shortest path is correctly calculated.
+     */
+    @Test
+    void testDijkstra() {
+        // Testing Dijkstra's algorithm with a small graph
+        double[][] graph = {{0, 1, 2}, {INF, 0, 3}, {INF, INF, 0}};
+
+        double[] modifiedWeights = {0, 0, 0}; // No reweighting in this simple case
+
+        double[] result = JohnsonsAlgorithm.dijkstra(graph, 0, modifiedWeights);
+        double[] expected = {0, 1, 2};
+
+        assertArrayEquals(expected, result);
+    }
+
+    /**
+     * Tests the conversion of an adjacency matrix to an edge list.
+     * Verifies that the conversion process generates the correct edge list.
+     */
+    @Test
+    void testEdgeListConversion() {
+        // Test the conversion of adjacency matrix to edge list
+        double[][] graph = {{0, 5, INF}, {INF, 0, 2}, {INF, INF, 0}};
+
+        // Running convertToEdgeList
+        double[][] edges = JohnsonsAlgorithm.convertToEdgeList(graph);
+
+        // Expected edge list: (0 -> 1, weight 5), (1 -> 2, weight 2)
+        double[][] expected = {{0, 1, 5}, {1, 2, 2}};
+
+        // Verify the edge list matches the expected values
+        assertArrayEquals(expected, edges);
+    }
+
+    /**
+     * Tests the reweighting of a graph as a part of Johnson's Algorithm.
+     * Verifies that the reweighted graph produces correct results.
+     */
+    @Test
+    void testReweightGraph() {
+        // Test reweighting of the graph
+        double[][] graph = {{0, 2, 9}, {INF, 0, 1}, {INF, INF, 0}};
+        double[] modifiedWeights = {1, 2, 3}; // Arbitrary weight function
+
+        double[][] reweightedGraph = JohnsonsAlgorithm.reweightGraph(graph, modifiedWeights);
+
+        // Expected reweighted graph:
+        double[][] expected = {{0, 1, 7}, {INF, 0, 0}, {INF, INF, 0}};
+
+        assertArrayEquals(expected, reweightedGraph);
+    }
+
+    /**
+     * Tests the minDistance method used in Dijkstra's algorithm to find
+     * the vertex with the minimum distance that has not yet been visited.
+     */
+    @Test
+    void testMinDistance() {
+        // Test minDistance method
+        double[] dist = {INF, 3, 1, INF};
+        boolean[] visited = {false, false, false, false};
+
+        int minIndex = JohnsonsAlgorithm.minDistance(dist, visited);
+
+        // The vertex with minimum distance is vertex 2 with a distance of 1
+        assertEquals(2, minIndex);
+    }
+}

From 1617ed1368eb303a3b77d948f74225267c4bf235 Mon Sep 17 00:00:00 2001
From: Tuhinm2002 <75078694+Tuhinm2002@users.noreply.github.com>
Date: Sun, 13 Oct 2024 00:17:42 +0530
Subject: [PATCH 0528/1338] feat : new bit manipulation algo `FindNthBit` of a
 number (#5731)

* feat : new algo uniquesubseqcount

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCountTest.java

* Update UniqueSubsequencesCount.java

* feat : new bitmanipulation algo

* feat :  new bit algo

* Update FindNthBitTest.java

* Update FindNthBit.java

---------

Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 .../bitmanipulation/FindNthBit.java           | 46 +++++++++++++++++++
 .../bitmanipulation/FindNthBitTest.java       | 39 ++++++++++++++++
 2 files changed, 85 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/FindNthBit.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/FindNthBitTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/FindNthBit.java b/src/main/java/com/thealgorithms/bitmanipulation/FindNthBit.java
new file mode 100644
index 000000000000..7a35fc3feebf
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/FindNthBit.java
@@ -0,0 +1,46 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * A utility class to find the Nth bit of a given number.
+ *
+ * <p>This class provides a method to extract the value of the Nth bit (either 0 or 1)
+ * from the binary representation of a given integer.
+ *
+ * <p>Example:
+ * <pre>{@code
+ * int result = FindNthBit.findNthBit(5, 2); // returns 0 as the 2nd bit of 5 (binary 101) is 0.
+ * }</pre>
+ *
+ * <p>Author: <a href="https://github.com/Tuhinm2002">Tuhinm2002</a>
+ */
+public final class FindNthBit {
+
+    /**
+     * Private constructor to prevent instantiation.
+     *
+     * <p>This is a utility class, and it should not be instantiated.
+     * Attempting to instantiate this class will throw an UnsupportedOperationException.
+     */
+    private FindNthBit() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    /**
+     * Finds the value of the Nth bit of the given number.
+     *
+     * <p>This method uses bitwise operations to extract the Nth bit from the
+     * binary representation of the given integer.
+     *
+     * @param num the integer number whose Nth bit is to be found
+     * @param n   the bit position (1-based) to retrieve
+     * @return    the value of the Nth bit (0 or 1)
+     * @throws IllegalArgumentException if the bit position is less than 1
+     */
+    public static int findNthBit(int num, int n) {
+        if (n < 1) {
+            throw new IllegalArgumentException("Bit position must be greater than or equal to 1.");
+        }
+        // Shifting the number to the right by (n - 1) positions and checking the last bit
+        return (num & (1 << (n - 1))) >> (n - 1);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/FindNthBitTest.java b/src/test/java/com/thealgorithms/bitmanipulation/FindNthBitTest.java
new file mode 100644
index 000000000000..978003d21358
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/FindNthBitTest.java
@@ -0,0 +1,39 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public final class FindNthBitTest {
+
+    /**
+     * A parameterized test that checks the value of the Nth bit for different inputs.
+     *
+     * @param num     the number whose Nth bit is being tested
+     * @param n       the bit position
+     * @param expected the expected value of the Nth bit (0 or 1)
+     */
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void findNthBitParameterizedTest(int num, int n, int expected) {
+        assertEquals(expected, FindNthBit.findNthBit(num, n));
+    }
+
+    /**
+     * Provides the test cases as a stream of arguments for the parameterized test.
+     *
+     * @return a stream of test cases where each case consists of a number, the bit position,
+     * and the expected result.
+     */
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(13, 2, 0), // binary: 1101, 2nd bit is 0
+            Arguments.of(13, 3, 1), // binary: 1101, 3rd bit is 1
+            Arguments.of(4, 2, 0), // binary: 100, 2nd bit is 0
+            Arguments.of(4, 3, 1), // binary: 100, 3rd bit is 1
+            Arguments.of(1, 1, 1) // binary: 1, 1st bit is 1
+        );
+    }
+}

From 4a03f420616a6773e9a5cdc304b1681e96d945bd Mon Sep 17 00:00:00 2001
From: vansh kabra <134841334+VANSH3104@users.noreply.github.com>
Date: Sun, 13 Oct 2024 00:28:52 +0530
Subject: [PATCH 0529/1338] Add algo for BooleanGateslogic (#5717)

---
 .../bitmanipulation/BooleanAlgebraGates.java  | 111 ++++++++++++++++++
 .../BooleanAlgebraGatesTest.java              | 101 ++++++++++++++++
 2 files changed, 212 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGates.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGatesTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGates.java b/src/main/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGates.java
new file mode 100644
index 000000000000..869466320831
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGates.java
@@ -0,0 +1,111 @@
+package com.thealgorithms.bitmanipulation;
+
+import java.util.List;
+
+/**
+ * Implements various Boolean algebra gates (AND, OR, NOT, XOR, NAND, NOR)
+ */
+public final class BooleanAlgebraGates {
+
+    private BooleanAlgebraGates() {
+        // Prevent instantiation
+    }
+
+    /**
+     * Represents a Boolean gate that takes multiple inputs and returns a result.
+     */
+    interface BooleanGate {
+        /**
+         * Evaluates the gate with the given inputs.
+         *
+         * @param inputs The input values for the gate.
+         * @return The result of the evaluation.
+         */
+        boolean evaluate(List<Boolean> inputs);
+    }
+
+    /**
+     * AND Gate implementation.
+     * Returns true if all inputs are true; otherwise, false.
+     */
+    static class ANDGate implements BooleanGate {
+        @Override
+        public boolean evaluate(List<Boolean> inputs) {
+            for (boolean input : inputs) {
+                if (!input) {
+                    return false;
+                }
+            }
+            return true;
+        }
+    }
+
+    /**
+     * OR Gate implementation.
+     * Returns true if at least one input is true; otherwise, false.
+     */
+    static class ORGate implements BooleanGate {
+        @Override
+        public boolean evaluate(List<Boolean> inputs) {
+            for (boolean input : inputs) {
+                if (input) {
+                    return true;
+                }
+            }
+            return false;
+        }
+    }
+
+    /**
+     * NOT Gate implementation (Unary operation).
+     * Negates a single input value.
+     */
+    static class NOTGate {
+        /**
+         * Evaluates the negation of the input.
+         *
+         * @param input The input value to be negated.
+         * @return The negated value.
+         */
+        public boolean evaluate(boolean input) {
+            return !input;
+        }
+    }
+
+    /**
+     * XOR Gate implementation.
+     * Returns true if an odd number of inputs are true; otherwise, false.
+     */
+    static class XORGate implements BooleanGate {
+        @Override
+        public boolean evaluate(List<Boolean> inputs) {
+            boolean result = false;
+            for (boolean input : inputs) {
+                result ^= input;
+            }
+            return result;
+        }
+    }
+
+    /**
+     * NAND Gate implementation.
+     * Returns true if at least one input is false; otherwise, false.
+     */
+    static class NANDGate implements BooleanGate {
+        @Override
+        public boolean evaluate(List<Boolean> inputs) {
+            return !new ANDGate().evaluate(inputs); // Equivalent to negation of AND
+        }
+    }
+
+    /**
+     * NOR Gate implementation.
+     * Returns true if all inputs are false; otherwise, false.
+     */
+    static class NORGate implements BooleanGate {
+        @Override
+        public boolean evaluate(List<Boolean> inputs) {
+            return !new ORGate().evaluate(inputs); // Equivalent to negation of OR
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGatesTest.java b/src/test/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGatesTest.java
new file mode 100644
index 000000000000..8737d05ec459
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGatesTest.java
@@ -0,0 +1,101 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.thealgorithms.bitmanipulation.BooleanAlgebraGates.ANDGate;
+import com.thealgorithms.bitmanipulation.BooleanAlgebraGates.BooleanGate;
+import com.thealgorithms.bitmanipulation.BooleanAlgebraGates.NANDGate;
+import com.thealgorithms.bitmanipulation.BooleanAlgebraGates.NORGate;
+import com.thealgorithms.bitmanipulation.BooleanAlgebraGates.NOTGate;
+import com.thealgorithms.bitmanipulation.BooleanAlgebraGates.ORGate;
+import com.thealgorithms.bitmanipulation.BooleanAlgebraGates.XORGate;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class BooleanAlgebraGatesTest {
+
+    @ParameterizedTest(name = "ANDGate Test Case {index}: inputs={0} -> expected={1}")
+    @MethodSource("provideAndGateTestCases")
+    void testANDGate(List<Boolean> inputs, boolean expected) {
+        BooleanGate gate = new ANDGate();
+        assertEquals(expected, gate.evaluate(inputs));
+    }
+
+    @ParameterizedTest(name = "ORGate Test Case {index}: inputs={0} -> expected={1}")
+    @MethodSource("provideOrGateTestCases")
+    void testORGate(List<Boolean> inputs, boolean expected) {
+        BooleanGate gate = new ORGate();
+        assertEquals(expected, gate.evaluate(inputs));
+    }
+
+    @ParameterizedTest(name = "NOTGate Test Case {index}: input={0} -> expected={1}")
+    @CsvSource({"true, false", "false, true"})
+    void testNOTGate(boolean input, boolean expected) {
+        NOTGate gate = new NOTGate();
+        assertEquals(expected, gate.evaluate(input));
+    }
+
+    @ParameterizedTest(name = "XORGate Test Case {index}: inputs={0} -> expected={1}")
+    @MethodSource("provideXorGateTestCases")
+    void testXORGate(List<Boolean> inputs, boolean expected) {
+        BooleanGate gate = new XORGate();
+        assertEquals(expected, gate.evaluate(inputs));
+    }
+
+    @ParameterizedTest(name = "NANDGate Test Case {index}: inputs={0} -> expected={1}")
+    @MethodSource("provideNandGateTestCases")
+    void testNANDGate(List<Boolean> inputs, boolean expected) {
+        BooleanGate gate = new NANDGate();
+        assertEquals(expected, gate.evaluate(inputs));
+    }
+
+    @ParameterizedTest(name = "NORGate Test Case {index}: inputs={0} -> expected={1}")
+    @MethodSource("provideNorGateTestCases")
+    void testNORGate(List<Boolean> inputs, boolean expected) {
+        BooleanGate gate = new NORGate();
+        assertEquals(expected, gate.evaluate(inputs));
+    }
+
+    // Helper methods to provide test data for each gate
+
+    static Stream<Object[]> provideAndGateTestCases() {
+        return Stream.of(new Object[] {Arrays.asList(Boolean.TRUE, Boolean.TRUE, Boolean.TRUE), Boolean.TRUE}, new Object[] {Arrays.asList(Boolean.TRUE, Boolean.FALSE, Boolean.TRUE), Boolean.FALSE}, new Object[] {Arrays.asList(Boolean.FALSE, Boolean.FALSE, Boolean.FALSE), Boolean.FALSE},
+            new Object[] {Collections.emptyList(), Boolean.TRUE} // AND over no inputs is true
+        );
+    }
+
+    static Stream<Object[]> provideOrGateTestCases() {
+        return Stream.of(new Object[] {Arrays.asList(Boolean.TRUE, Boolean.FALSE, Boolean.FALSE), Boolean.TRUE}, new Object[] {Arrays.asList(Boolean.FALSE, Boolean.FALSE, Boolean.FALSE), Boolean.FALSE}, new Object[] {Arrays.asList(Boolean.TRUE, Boolean.TRUE, Boolean.TRUE), Boolean.TRUE},
+            new Object[] {Collections.emptyList(), Boolean.FALSE} // OR over no inputs is false
+        );
+    }
+
+    static Stream<Object[]> provideXorGateTestCases() {
+        return Stream.of(new Object[] {Arrays.asList(Boolean.TRUE, Boolean.FALSE, Boolean.TRUE), Boolean.FALSE}, // XOR over odd true
+            new Object[] {Arrays.asList(Boolean.TRUE, Boolean.FALSE, Boolean.FALSE), Boolean.TRUE}, // XOR over single true
+            new Object[] {Arrays.asList(Boolean.FALSE, Boolean.FALSE, Boolean.FALSE), Boolean.FALSE}, // XOR over all false
+            new Object[] {Arrays.asList(Boolean.TRUE, Boolean.TRUE), Boolean.FALSE} // XOR over even true
+        );
+    }
+
+    static Stream<Object[]> provideNandGateTestCases() {
+        return Stream.of(new Object[] {Arrays.asList(Boolean.TRUE, Boolean.TRUE, Boolean.TRUE), Boolean.FALSE}, // NAND of all true is false
+            new Object[] {Arrays.asList(Boolean.TRUE, Boolean.FALSE), Boolean.TRUE}, // NAND with one false is true
+            new Object[] {Arrays.asList(Boolean.FALSE, Boolean.FALSE), Boolean.TRUE}, // NAND of all false is true
+            new Object[] {Collections.emptyList(), Boolean.FALSE} // NAND over no inputs is false (negation of AND)
+        );
+    }
+
+    static Stream<Object[]> provideNorGateTestCases() {
+        return Stream.of(new Object[] {Arrays.asList(Boolean.FALSE, Boolean.FALSE), Boolean.TRUE}, // NOR of all false is true
+            new Object[] {Arrays.asList(Boolean.FALSE, Boolean.TRUE), Boolean.FALSE}, // NOR with one true is false
+            new Object[] {Arrays.asList(Boolean.TRUE, Boolean.TRUE), Boolean.FALSE}, // NOR of all true is false
+            new Object[] {Collections.emptyList(), Boolean.TRUE} // NOR over no inputs is true (negation of OR)
+        );
+    }
+}

From 6682c7c76e2bf016e2e7b51a6027ac30d354b13e Mon Sep 17 00:00:00 2001
From: Tanmay-Singh3004 <156223260+Tanmay-Singh3004@users.noreply.github.com>
Date: Sun, 13 Oct 2024 11:52:57 +0530
Subject: [PATCH 0530/1338] Add BcdConversion algorithm (#5742)

---
 DIRECTORY.md                                  |  2 +
 .../bitmanipulation/BcdConversion.java        | 58 +++++++++++++++++
 .../bitmanipulation/BcdConversionTest.java    | 65 +++++++++++++++++++
 3 files changed, 125 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 30fa2cbee199..af956a1a26ed 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -23,6 +23,7 @@
             * [WordPatternMatcher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordPatternMatcher.java)
             * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
           * bitmanipulation
+            * [BcdConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java)
             * [BinaryPalindromeCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java)
             * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
             * [ClearLeftmostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java)
@@ -654,6 +655,7 @@
             * [WordPatternMatcherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordPatternMatcherTest.java)
             * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
           * bitmanipulation
+            * [BcdConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java)
             * [BinaryPalindromeCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java)
             * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
             * [ClearLeftmostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java b/src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java
new file mode 100644
index 000000000000..3cf8411816c7
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class provides methods to convert between BCD (Binary-Coded Decimal) and binary.
+ *
+ * Binary-Coded Decimal (BCD) is a class of binary encodings of decimal numbers where each decimal digit is represented by a fixed number of binary digits, usually four or eight.
+ *
+ * For more information, refer to the
+ * <a href="https://en.wikipedia.org/wiki/Binary-coded_decimal">Binary-Coded Decimal</a> Wikipedia page.
+ *
+ * <b>Example usage:</b>
+ * <pre>
+ * int binary = BcdConversion.bcdToBinary(0x1234);
+ * System.out.println("BCD 0x1234 to binary: " + binary); // Output: 1234
+ *
+ * int bcd = BcdConversion.binaryToBcd(1234);
+ * System.out.println("Binary 1234 to BCD: " + Integer.toHexString(bcd)); // Output: 0x1234
+ * </pre>
+ */
+public final class BcdConversion {
+    private BcdConversion() {
+    }
+    /**
+     * Converts a BCD (Binary-Coded Decimal) number to binary.
+     *
+     * @param bcd The BCD number.
+     * @return The corresponding binary number.
+     */
+    public static int bcdToBinary(int bcd) {
+        int binary = 0;
+        int multiplier = 1;
+        while (bcd > 0) {
+            int digit = bcd & 0xF; // Extract the last 4 bits (one BCD digit)
+            binary += digit * multiplier;
+            multiplier *= 10;
+            bcd >>= 4; // Shift right by 4 bits to process the next BCD digit
+        }
+        return binary;
+    }
+
+    /**
+     * Converts a binary number to BCD (Binary-Coded Decimal).
+     *
+     * @param binary The binary number.
+     * @return The corresponding BCD number.
+     */
+    public static int binaryToBcd(int binary) {
+        int bcd = 0;
+        int shift = 0;
+        while (binary > 0) {
+            int digit = binary % 10; // Extract the last decimal digit
+            bcd |= (digit << (shift * 4)); // Shift the digit to the correct BCD position
+            binary /= 10; // Remove the last decimal digit
+            shift++;
+        }
+        return bcd;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java b/src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java
new file mode 100644
index 000000000000..85221d92ad42
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java
@@ -0,0 +1,65 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the BcdConversion class.
+ */
+public class BcdConversionTest {
+
+    /**
+     * Test the bcdToBinary method with a BCD number.
+     */
+    @Test
+    public void testBcdToBinary() {
+        int binary = BcdConversion.bcdToBinary(0x1234);
+        assertEquals(1234, binary); // BCD 0x1234 should convert to binary 1234
+    }
+
+    /**
+     * Test the binaryToBcd method with a binary number.
+     */
+    @Test
+    public void testBinaryToBcd() {
+        int bcd = BcdConversion.binaryToBcd(1234);
+        assertEquals(0x1234, bcd); // Binary 1234 should convert to BCD 0x1234
+    }
+
+    /**
+     * Test the bcdToBinary method with zero.
+     */
+    @Test
+    public void testBcdToBinaryZero() {
+        int binary = BcdConversion.bcdToBinary(0x0);
+        assertEquals(0, binary); // BCD 0x0 should convert to binary 0
+    }
+
+    /**
+     * Test the binaryToBcd method with zero.
+     */
+    @Test
+    public void testBinaryToBcdZero() {
+        int bcd = BcdConversion.binaryToBcd(0);
+        assertEquals(0x0, bcd); // Binary 0 should convert to BCD 0x0
+    }
+
+    /**
+     * Test the bcdToBinary method with a single digit BCD number.
+     */
+    @Test
+    public void testBcdToBinarySingleDigit() {
+        int binary = BcdConversion.bcdToBinary(0x7);
+        assertEquals(7, binary); // BCD 0x7 should convert to binary 7
+    }
+
+    /**
+     * Test the binaryToBcd method with a single digit binary number.
+     */
+    @Test
+    public void testBinaryToBcdSingleDigit() {
+        int bcd = BcdConversion.binaryToBcd(7);
+        assertEquals(0x7, bcd); // Binary 7 should convert to BCD 0x7
+    }
+}

From 6af7f7b126fd45d755d197b23defe66bba6508fa Mon Sep 17 00:00:00 2001
From: Tanmay-Singh3004 <156223260+Tanmay-Singh3004@users.noreply.github.com>
Date: Sun, 13 Oct 2024 14:00:09 +0530
Subject: [PATCH 0531/1338] Add Xs3Conversion algorithm (#5743)

---
 DIRECTORY.md                                  |  2 +
 .../bitmanipulation/Xs3Conversion.java        | 58 +++++++++++++++++
 .../bitmanipulation/Xs3ConversionTest.java    | 65 +++++++++++++++++++
 3 files changed, 125 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/Xs3Conversion.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/Xs3ConversionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index af956a1a26ed..09407e342180 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -47,6 +47,7 @@
             * [SingleElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleElement.java)
             * [SwapAdjacentBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java)
             * [TwosComplement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java)
+            * [Xs3Conversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/Xs3Conversion.java)
           * ciphers
             * a5
               * [A5Cipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/A5Cipher.java)
@@ -679,6 +680,7 @@
             * [SingleElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleElementTest.java)
             * [SwapAdjacentBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java)
             * [TwosComplementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java)
+            * [Xs3ConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/Xs3ConversionTest.java)
           * ciphers
             * a5
               * [A5CipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/Xs3Conversion.java b/src/main/java/com/thealgorithms/bitmanipulation/Xs3Conversion.java
new file mode 100644
index 000000000000..b22abc0c04ff
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/Xs3Conversion.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class provides methods to convert between XS-3 (Excess-3) and binary.
+ *
+ * Excess-3, also called XS-3, is a binary-coded decimal (BCD) code in which each decimal digit is represented by its corresponding 4-bit binary value plus 3.
+ *
+ * For more information, refer to the
+ * <a href="https://en.wikipedia.org/wiki/Excess-3">Excess-3</a> Wikipedia page.
+ *
+ * <b>Example usage:</b>
+ * <pre>
+ * int binary = Xs3Conversion.xs3ToBinary(0x4567);
+ * System.out.println("XS-3 0x4567 to binary: " + binary); // Output: 1234
+ *
+ * int xs3 = Xs3Conversion.binaryToXs3(1234);
+ * System.out.println("Binary 1234 to XS-3: " + Integer.toHexString(xs3)); // Output: 0x4567
+ * </pre>
+ */
+public final class Xs3Conversion {
+    private Xs3Conversion() {
+    }
+    /**
+     * Converts an XS-3 (Excess-3) number to binary.
+     *
+     * @param xs3 The XS-3 number.
+     * @return The corresponding binary number.
+     */
+    public static int xs3ToBinary(int xs3) {
+        int binary = 0;
+        int multiplier = 1;
+        while (xs3 > 0) {
+            int digit = (xs3 & 0xF) - 3; // Extract the last 4 bits (one XS-3 digit) and subtract 3
+            binary += digit * multiplier;
+            multiplier *= 10;
+            xs3 >>= 4; // Shift right by 4 bits to process the next XS-3 digit
+        }
+        return binary;
+    }
+
+    /**
+     * Converts a binary number to XS-3 (Excess-3).
+     *
+     * @param binary The binary number.
+     * @return The corresponding XS-3 number.
+     */
+    public static int binaryToXs3(int binary) {
+        int xs3 = 0;
+        int shift = 0;
+        while (binary > 0) {
+            int digit = (binary % 10) + 3; // Extract the last decimal digit and add 3
+            xs3 |= (digit << (shift * 4)); // Shift the digit to the correct XS-3 position
+            binary /= 10; // Remove the last decimal digit
+            shift++;
+        }
+        return xs3;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/Xs3ConversionTest.java b/src/test/java/com/thealgorithms/bitmanipulation/Xs3ConversionTest.java
new file mode 100644
index 000000000000..2e3242decba0
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/Xs3ConversionTest.java
@@ -0,0 +1,65 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the Xs3Conversion class.
+ */
+public class Xs3ConversionTest {
+
+    /**
+     * Test the xs3ToBinary method with an XS-3 number.
+     */
+    @Test
+    public void testXs3ToBinary() {
+        int binary = Xs3Conversion.xs3ToBinary(0x4567);
+        assertEquals(1234, binary); // XS-3 0x4567 should convert to binary 1234
+    }
+
+    /**
+     * Test the binaryToXs3 method with a binary number.
+     */
+    @Test
+    public void testBinaryToXs3() {
+        int xs3 = Xs3Conversion.binaryToXs3(1234);
+        assertEquals(0x4567, xs3); // Binary 1234 should convert to XS-3 0x4567
+    }
+
+    /**
+     * Test the xs3ToBinary method with zero.
+     */
+    @Test
+    public void testXs3ToBinaryZero() {
+        int binary = Xs3Conversion.xs3ToBinary(0x0);
+        assertEquals(0, binary); // XS-3 0x0 should convert to binary 0
+    }
+
+    /**
+     * Test the binaryToXs3 method with zero.
+     */
+    @Test
+    public void testBinaryToXs3Zero() {
+        int xs3 = Xs3Conversion.binaryToXs3(0);
+        assertEquals(0x0, xs3); // Binary 0 should convert to XS-3 0x0
+    }
+
+    /**
+     * Test the xs3ToBinary method with a single digit XS-3 number.
+     */
+    @Test
+    public void testXs3ToBinarySingleDigit() {
+        int binary = Xs3Conversion.xs3ToBinary(0x5);
+        assertEquals(2, binary); // XS-3 0x5 should convert to binary 2
+    }
+
+    /**
+     * Test the binaryToXs3 method with a single digit binary number.
+     */
+    @Test
+    public void testBinaryToXs3SingleDigit() {
+        int xs3 = Xs3Conversion.binaryToXs3(2);
+        assertEquals(0x5, xs3); // Binary 2 should convert to XS-3 0x5
+    }
+}

From 596c6147af0af91d1ca8990ed91820df1fe3b8ea Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 13 Oct 2024 15:00:53 +0530
Subject: [PATCH 0532/1338] Add function documentation, enhance comments in
 TowerOfHanoi.java (#5533)

---
 DIRECTORY.md                                  | 13 +++-
 .../thealgorithms/others/TowerOfHanoi.java    | 72 ++++++++++++++-----
 .../others/TowerOfHanoiTest.java              | 50 +++++++++++++
 3 files changed, 116 insertions(+), 19 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/TowerOfHanoiTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 09407e342180..06307d4aca78 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -26,9 +26,11 @@
             * [BcdConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java)
             * [BinaryPalindromeCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java)
             * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
+            * [BooleanAlgebraGates](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGates.java)
             * [ClearLeftmostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java)
             * [CountLeadingZeros](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java)
             * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
+            * [FindNthBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/FindNthBit.java)
             * [GrayCodeConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java)
             * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java)
             * [HigherLowerPowerOfTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java)
@@ -56,6 +58,7 @@
               * [CompositeLFSR](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java)
               * [LFSR](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/LFSR.java)
               * [Utils](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/Utils.java)
+            * [ADFGVXCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java)
             * [AES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AES.java)
             * [AESEncryption](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AESEncryption.java)
             * [AffineCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AffineCipher.java)
@@ -135,6 +138,7 @@
               * [FordFulkerson](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java)
               * [Graphs](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java)
               * [HamiltonianCycle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java)
+              * [JohnsonsAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java)
               * [KahnsAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java)
               * [Kosaraju](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java)
               * [Kruskal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java)
@@ -342,6 +346,7 @@
             * [EulersFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/EulersFunction.java)
             * [Factorial](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Factorial.java)
             * [FactorialRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FactorialRecursion.java)
+            * [FastExponentiation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FastExponentiation.java)
             * [FastInverseSqrt](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java)
             * [FFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FFT.java)
             * [FFTBluestein](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FFTBluestein.java)
@@ -659,9 +664,11 @@
             * [BcdConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java)
             * [BinaryPalindromeCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java)
             * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
+            * [BooleanAlgebraGatesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGatesTest.java)
             * [ClearLeftmostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java)
             * [CountLeadingZerosTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java)
             * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
+            * [FindNthBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/FindNthBitTest.java)
             * [GrayCodeConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java)
             * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java)
             * [HigherLowerPowerOfTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java)
@@ -680,12 +687,13 @@
             * [SingleElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleElementTest.java)
             * [SwapAdjacentBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java)
             * [TwosComplementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java)
-            * [Xs3ConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/Xs3ConversionTest.java)
+            * [Xs3ConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/Xs3ConversionTest.java)
           * ciphers
             * a5
               * [A5CipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java)
               * [A5KeyStreamGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java)
               * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
+            * [ADFGVXCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java)
             * [AESEncryptionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java)
             * [AffineCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java)
             * [AtbashTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AtbashTest.java)
@@ -754,6 +762,7 @@
               * [FloydWarshallTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FloydWarshallTest.java)
               * [FordFulkersonTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java)
               * [HamiltonianCycleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java)
+              * [JohnsonsAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java)
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
               * [TarjansAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
               * [WelshPowellTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java)
@@ -906,6 +915,7 @@
             * [EulersFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/EulersFunctionTest.java)
             * [FactorialRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java)
             * [FactorialTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialTest.java)
+            * [FastExponentiationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FastExponentiationTest.java)
             * [FastInverseSqrtTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java)
             * [FFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FFTTest.java)
             * [FibonacciJavaStreamsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciJavaStreamsTest.java)
@@ -1014,6 +1024,7 @@
             * [SkylineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
             * [SudokuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SudokuTest.java)
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
+            * [TowerOfHanoiTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TowerOfHanoiTest.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
           * Recursion
diff --git a/src/main/java/com/thealgorithms/others/TowerOfHanoi.java b/src/main/java/com/thealgorithms/others/TowerOfHanoi.java
index 2216799b987a..7017ed03f843 100644
--- a/src/main/java/com/thealgorithms/others/TowerOfHanoi.java
+++ b/src/main/java/com/thealgorithms/others/TowerOfHanoi.java
@@ -1,29 +1,65 @@
 package com.thealgorithms.others;
 
-import java.util.Scanner;
+import java.util.List;
 
+/**
+ * The {@code TowerOfHanoi} class provides a recursive solution to the Tower of Hanoi puzzle.
+ * This puzzle involves moving a set of discs from one pole to another, following specific rules:
+ * 1. Only one disc can be moved at a time.
+ * 2. A disc can only be placed on top of a larger disc.
+ * 3. All discs must start on one pole and end on another.
+ *
+ * This implementation recursively calculates the steps required to solve the puzzle and stores them
+ * in a provided list.
+ *
+ * <p>
+ * For more information about the Tower of Hanoi, see
+ * <a href="https://en.wikipedia.org/wiki/Tower_of_Hanoi">Tower of Hanoi on Wikipedia</a>.
+ * </p>
+ *
+ * The {@code shift} method takes the number of discs and the names of the poles,
+ * and appends the steps required to solve the puzzle to the provided list.
+ * Time Complexity: O(2^n) - Exponential time complexity due to the recursive nature of the problem.
+ * Space Complexity: O(n) - Linear space complexity due to the recursion stack.
+ * Wikipedia: https://en.wikipedia.org/wiki/Tower_of_Hanoi
+ */
 final class TowerOfHanoi {
+
     private TowerOfHanoi() {
     }
 
-    public static void shift(int n, String startPole, String intermediatePole, String endPole) {
-        // if n becomes zero the program returns thus ending the loop.
+    /**
+     * Recursively solve the Tower of Hanoi puzzle by moving discs between poles.
+     *
+     * @param n                The number of discs to move.
+     * @param startPole        The name of the start pole from which discs are moved.
+     * @param intermediatePole The name of the intermediate pole used as a temporary holding area.
+     * @param endPole          The name of the end pole to which discs are moved.
+     * @param result           A list to store the steps required to solve the puzzle.
+     *
+     *                         <p>
+     *                         This method is called recursively to move n-1 discs
+     *                         to the intermediate pole,
+     *                         then moves the nth disc to the end pole, and finally
+     *                         moves the n-1 discs from the
+     *                         intermediate pole to the end pole.
+     *                         </p>
+     *
+     *                         <p>
+     *                         Time Complexity: O(2^n) - Exponential time complexity due to the recursive nature of the problem.
+     *                         Space Complexity: O(n) - Linear space complexity due to the recursion stack.
+     *                         </p>
+     */
+    public static void shift(int n, String startPole, String intermediatePole, String endPole, List<String> result) {
         if (n != 0) {
-            // Shift function is called in recursion for swapping the n-1 disc from the startPole to
-            // the intermediatePole
-            shift(n - 1, startPole, endPole, intermediatePole);
-            System.out.format("Move %d from %s to %s%n", n, startPole, endPole); // Result Printing
-            // Shift function is called in recursion for swapping the n-1 disc from the
-            // intermediatePole to the endPole
-            shift(n - 1, intermediatePole, startPole, endPole);
-        }
-    }
+            // Move n-1 discs from startPole to intermediatePole
+            shift(n - 1, startPole, endPole, intermediatePole, result);
 
-    public static void main(String[] args) {
-        System.out.print("Enter number of discs on Pole 1: ");
-        Scanner scanner = new Scanner(System.in);
-        int numberOfDiscs = scanner.nextInt(); // input of number of discs on pole 1
-        shift(numberOfDiscs, "Pole1", "Pole2", "Pole3"); // Shift function called
-        scanner.close();
+            // Add the move of the nth disc from startPole to endPole
+            result.add(String.format("Move %d from %s to %s", n, startPole, endPole));
+
+            // Move the n-1 discs from intermediatePole to endPole
+            shift(n - 1, intermediatePole, startPole, endPole, result);
+        }
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/TowerOfHanoiTest.java b/src/test/java/com/thealgorithms/others/TowerOfHanoiTest.java
new file mode 100644
index 000000000000..ca9376dd48eb
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/TowerOfHanoiTest.java
@@ -0,0 +1,50 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class TowerOfHanoiTest {
+
+    @Test
+    public void testHanoiWithOneDisc() {
+        List<String> result = new ArrayList<>();
+        TowerOfHanoi.shift(1, "Pole1", "Pole2", "Pole3", result);
+
+        // Expected output for 1 disc
+        List<String> expected = List.of("Move 1 from Pole1 to Pole3");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testHanoiWithTwoDiscs() {
+        List<String> result = new ArrayList<>();
+        TowerOfHanoi.shift(2, "Pole1", "Pole2", "Pole3", result);
+
+        // Expected output for 2 discs
+        List<String> expected = List.of("Move 1 from Pole1 to Pole2", "Move 2 from Pole1 to Pole3", "Move 1 from Pole2 to Pole3");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testHanoiWithThreeDiscs() {
+        List<String> result = new ArrayList<>();
+        TowerOfHanoi.shift(3, "Pole1", "Pole2", "Pole3", result);
+
+        // Expected output for 3 discs
+        List<String> expected = List.of("Move 1 from Pole1 to Pole3", "Move 2 from Pole1 to Pole2", "Move 1 from Pole3 to Pole2", "Move 3 from Pole1 to Pole3", "Move 1 from Pole2 to Pole1", "Move 2 from Pole2 to Pole3", "Move 1 from Pole1 to Pole3");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testHanoiWithZeroDiscs() {
+        List<String> result = new ArrayList<>();
+        TowerOfHanoi.shift(0, "Pole1", "Pole2", "Pole3", result);
+
+        // There should be no moves if there are 0 discs
+        assertTrue(result.isEmpty());
+    }
+}

From b0c8a8f0ce8ad4820f7a79550b33178023b31622 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 13 Oct 2024 16:20:31 +0530
Subject: [PATCH 0533/1338] feat: Add `PostfixEvaluator` new algorithm with
 Junit tests (#5754)

---
 DIRECTORY.md                                  |  2 +
 .../stacks/PostfixEvaluator.java              | 74 +++++++++++++++++++
 .../stacks/PostfixEvaluatorTest.java          | 27 +++++++
 3 files changed, 103 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 06307d4aca78..a78efffb8d85 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -598,6 +598,7 @@
             * [MaximumMinimumWindow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java)
             * [NextGreaterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java)
             * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
+            * [PostfixEvaluator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java)
             * [PostfixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java)
             * [PrefixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PrefixToInfix.java)
             * [SortStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/SortStack.java)
@@ -1128,6 +1129,7 @@
             * [LargestRectangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java)
             * [NextGreaterElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java)
             * [NextSmallerElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
+            * [PostfixEvaluatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java)
             * [PostfixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java)
             * [PrefixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java)
             * [SortStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/SortStackTest.java)
diff --git a/src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java b/src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java
new file mode 100644
index 000000000000..02ef5af8da16
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java
@@ -0,0 +1,74 @@
+package com.thealgorithms.stacks;
+
+import java.util.Set;
+import java.util.Stack;
+
+/**
+ * Evaluate a postfix (Reverse Polish) expression using a stack.
+ *
+ * <p>Example: Expression "5 6 + 2 *" results in 22.
+ * <p>Applications: Used in calculators and expression evaluation in compilers.
+ *
+ * @author Hardvan
+ */
+public final class PostfixEvaluator {
+    private PostfixEvaluator() {
+    }
+
+    private static final Set<String> OPERATORS = Set.of("+", "-", "*", "/");
+
+    /**
+     * Evaluates the given postfix expression and returns the result.
+     *
+     * @param expression The postfix expression as a string with operands and operators separated by spaces.
+     * @return The result of evaluating the postfix expression.
+     * @throws IllegalArgumentException if the expression is invalid.
+     */
+    public static int evaluatePostfix(String expression) {
+        Stack<Integer> stack = new Stack<>();
+
+        for (String token : expression.split("\\s+")) {
+            if (isOperator(token)) {
+                int operand2 = stack.pop();
+                int operand1 = stack.pop();
+                stack.push(applyOperator(token, operand1, operand2));
+            } else {
+                stack.push(Integer.valueOf(token));
+            }
+        }
+
+        if (stack.size() != 1) {
+            throw new IllegalArgumentException("Invalid expression");
+        }
+
+        return stack.pop();
+    }
+
+    /**
+     * Checks if the given token is an operator.
+     *
+     * @param token The token to check.
+     * @return true if the token is an operator, false otherwise.
+     */
+    private static boolean isOperator(String token) {
+        return OPERATORS.contains(token);
+    }
+
+    /**
+     * Applies the given operator to the two operands.
+     *
+     * @param operator The operator to apply.
+     * @param a The first operand.
+     * @param b The second operand.
+     * @return The result of applying the operator to the operands.
+     */
+    private static int applyOperator(String operator, int a, int b) {
+        return switch (operator) {
+            case "+" -> a + b;
+            case "-" -> a - b;
+            case "*" -> a * b;
+            case "/" -> a / b;
+            default -> throw new IllegalArgumentException("Invalid operator");
+        };
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java b/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java
new file mode 100644
index 000000000000..882fe644ccd5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java
@@ -0,0 +1,27 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.EmptyStackException;
+import org.junit.jupiter.api.Test;
+
+public class PostfixEvaluatorTest {
+
+    @Test
+    public void testValidExpressions() {
+        assertEquals(22, PostfixEvaluator.evaluatePostfix("5 6 + 2 *"));
+        assertEquals(27, PostfixEvaluator.evaluatePostfix("7 2 + 3 *"));
+        assertEquals(3, PostfixEvaluator.evaluatePostfix("10 5 / 1 +"));
+    }
+
+    @Test
+    public void testInvalidExpression() {
+        assertThrows(EmptyStackException.class, () -> PostfixEvaluator.evaluatePostfix("5 +"));
+    }
+
+    @Test
+    public void testMoreThanOneStackSizeAfterEvaluation() {
+        assertThrows(IllegalArgumentException.class, () -> PostfixEvaluator.evaluatePostfix("5 6 + 2 * 3"));
+    }
+}

From bae7f8915618c396b677428b314188ef566c6db5 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 13 Oct 2024 16:27:05 +0530
Subject: [PATCH 0534/1338] feat: Add `PrefixEvaluator` new algorithm with
 Junit tests (#5755)

---
 DIRECTORY.md                                  |  2 +
 .../thealgorithms/stacks/PrefixEvaluator.java | 76 +++++++++++++++++++
 .../stacks/PrefixEvaluatorTest.java           | 27 +++++++
 3 files changed, 105 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/PrefixEvaluator.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a78efffb8d85..d9beaadcba4d 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -600,6 +600,7 @@
             * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
             * [PostfixEvaluator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java)
             * [PostfixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java)
+            * [PrefixEvaluator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PrefixEvaluator.java)
             * [PrefixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PrefixToInfix.java)
             * [SortStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/SortStack.java)
             * [StackPostfixNotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
@@ -1131,6 +1132,7 @@
             * [NextSmallerElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
             * [PostfixEvaluatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java)
             * [PostfixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java)
+            * [PrefixEvaluatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java)
             * [PrefixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java)
             * [SortStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/SortStackTest.java)
             * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
diff --git a/src/main/java/com/thealgorithms/stacks/PrefixEvaluator.java b/src/main/java/com/thealgorithms/stacks/PrefixEvaluator.java
new file mode 100644
index 000000000000..eb2ce95e18d8
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/PrefixEvaluator.java
@@ -0,0 +1,76 @@
+package com.thealgorithms.stacks;
+
+import java.util.Set;
+import java.util.Stack;
+
+/**
+ * Evaluate a prefix (Polish) expression using a stack.
+ *
+ * <p>Example: Expression "+ * 2 3 4" results in 10.
+ * <p>Applications: Useful for implementing compilers and interpreters.
+ *
+ * @author Hardvan
+ */
+public final class PrefixEvaluator {
+    private PrefixEvaluator() {
+    }
+
+    private static final Set<String> OPERATORS = Set.of("+", "-", "*", "/");
+
+    /**
+     * Evaluates the given prefix expression and returns the result.
+     *
+     * @param expression The prefix expression as a string with operands and operators separated by spaces.
+     * @return The result of evaluating the prefix expression.
+     * @throws IllegalArgumentException if the expression is invalid.
+     */
+    public static int evaluatePrefix(String expression) {
+        Stack<Integer> stack = new Stack<>();
+        String[] tokens = expression.split("\\s+");
+
+        for (int i = tokens.length - 1; i >= 0; i--) {
+            String token = tokens[i];
+            if (isOperator(token)) {
+                int operand1 = stack.pop();
+                int operand2 = stack.pop();
+                stack.push(applyOperator(token, operand1, operand2));
+            } else {
+                stack.push(Integer.valueOf(token));
+            }
+        }
+
+        if (stack.size() != 1) {
+            throw new IllegalArgumentException("Invalid expression");
+        }
+
+        return stack.pop();
+    }
+
+    /**
+     * Checks if the given token is an operator.
+     *
+     * @param token The token to check.
+     * @return true if the token is an operator, false otherwise.
+     */
+    private static boolean isOperator(String token) {
+        return OPERATORS.contains(token);
+    }
+
+    /**
+     * Applies the given operator to the two operands.
+     *
+     * @param operator The operator to apply.
+     * @param a The first operand.
+     * @param b The second operand.
+     * @return The result of applying the operator to the operands.
+     */
+    private static int applyOperator(String operator, int a, int b) {
+        return switch (operator) {
+            case "+" -> a + b;
+            case "-" -> a - b;
+            case "*" -> a * b;
+            case "/" -> a / b;
+            default -> throw new IllegalArgumentException("Invalid operator");
+        };
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java b/src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java
new file mode 100644
index 000000000000..e2faa61955b3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java
@@ -0,0 +1,27 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.EmptyStackException;
+import org.junit.jupiter.api.Test;
+
+public class PrefixEvaluatorTest {
+
+    @Test
+    public void testValidExpressions() {
+        assertEquals(10, PrefixEvaluator.evaluatePrefix("+ * 2 3 4"));
+        assertEquals(5, PrefixEvaluator.evaluatePrefix("- + 7 3 5"));
+        assertEquals(6, PrefixEvaluator.evaluatePrefix("/ * 3 2 1"));
+    }
+
+    @Test
+    public void testInvalidExpression() {
+        assertThrows(EmptyStackException.class, () -> PrefixEvaluator.evaluatePrefix("+ 3"));
+    }
+
+    @Test
+    public void testMoreThanOneStackSizeAfterEvaluation() {
+        assertThrows(IllegalArgumentException.class, () -> PrefixEvaluator.evaluatePrefix("+ 3 4 5"));
+    }
+}

From e291516dc9b50f532c229aac398b1dd253d11a99 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 13 Oct 2024 16:50:20 +0530
Subject: [PATCH 0535/1338] Refactor BCD Conversion docs and add more tests
 (#5762)

---
 .../bitmanipulation/BcdConversion.java        | 66 +++++++++----
 .../bitmanipulation/BcdConversionTest.java    | 98 +++++++++++--------
 2 files changed, 104 insertions(+), 60 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java b/src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java
index 3cf8411816c7..e6bd35720d9f 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java
@@ -1,56 +1,80 @@
 package com.thealgorithms.bitmanipulation;
 
 /**
- * This class provides methods to convert between BCD (Binary-Coded Decimal) and binary.
+ * This class provides methods to convert between BCD (Binary-Coded Decimal) and decimal numbers.
  *
- * Binary-Coded Decimal (BCD) is a class of binary encodings of decimal numbers where each decimal digit is represented by a fixed number of binary digits, usually four or eight.
+ * BCD is a class of binary encodings of decimal numbers where each decimal digit is represented by a fixed number of binary digits, usually four or eight.
  *
  * For more information, refer to the
  * <a href="https://en.wikipedia.org/wiki/Binary-coded_decimal">Binary-Coded Decimal</a> Wikipedia page.
  *
  * <b>Example usage:</b>
  * <pre>
- * int binary = BcdConversion.bcdToBinary(0x1234);
- * System.out.println("BCD 0x1234 to binary: " + binary); // Output: 1234
+ * int decimal = BcdConversion.bcdToDecimal(0x1234);
+ * System.out.println("BCD 0x1234 to decimal: " + decimal); // Output: 1234
  *
- * int bcd = BcdConversion.binaryToBcd(1234);
- * System.out.println("Binary 1234 to BCD: " + Integer.toHexString(bcd)); // Output: 0x1234
+ * int bcd = BcdConversion.decimalToBcd(1234);
+ * System.out.println("Decimal 1234 to BCD: " + Integer.toHexString(bcd)); // Output: 0x1234
  * </pre>
  */
 public final class BcdConversion {
     private BcdConversion() {
     }
+
     /**
-     * Converts a BCD (Binary-Coded Decimal) number to binary.
+     * Converts a BCD (Binary-Coded Decimal) number to a decimal number.
+     * <p>Steps:
+     * <p>1. Validate the BCD number to ensure all digits are between 0 and 9.
+     * <p>2. Extract the last 4 bits (one BCD digit) from the BCD number.
+     * <p>3. Multiply the extracted digit by the corresponding power of 10 and add it to the decimal number.
+     * <p>4. Shift the BCD number right by 4 bits to process the next BCD digit.
+     * <p>5. Repeat steps 1-4 until the BCD number is zero.
      *
      * @param bcd The BCD number.
-     * @return The corresponding binary number.
+     * @return The corresponding decimal number.
+     * @throws IllegalArgumentException if the BCD number contains invalid digits.
      */
-    public static int bcdToBinary(int bcd) {
-        int binary = 0;
+    public static int bcdToDecimal(int bcd) {
+        int decimal = 0;
         int multiplier = 1;
+
+        // Validate BCD digits
         while (bcd > 0) {
-            int digit = bcd & 0xF; // Extract the last 4 bits (one BCD digit)
-            binary += digit * multiplier;
+            int digit = bcd & 0xF;
+            if (digit > 9) {
+                throw new IllegalArgumentException("Invalid BCD digit: " + digit);
+            }
+            decimal += digit * multiplier;
             multiplier *= 10;
-            bcd >>= 4; // Shift right by 4 bits to process the next BCD digit
+            bcd >>= 4;
         }
-        return binary;
+        return decimal;
     }
 
     /**
-     * Converts a binary number to BCD (Binary-Coded Decimal).
+     * Converts a decimal number to BCD (Binary-Coded Decimal).
+     * <p>Steps:
+     * <p>1. Check if the decimal number is within the valid range for BCD (0 to 9999).
+     * <p>2. Extract the last decimal digit from the decimal number.
+     * <p>3. Shift the digit to the correct BCD position and add it to the BCD number.
+     * <p>4. Remove the last decimal digit from the decimal number.
+     * <p>5. Repeat steps 2-4 until the decimal number is zero.
      *
-     * @param binary The binary number.
+     * @param decimal The decimal number.
      * @return The corresponding BCD number.
+     * @throws IllegalArgumentException if the decimal number is greater than 9999.
      */
-    public static int binaryToBcd(int binary) {
+    public static int decimalToBcd(int decimal) {
+        if (decimal < 0 || decimal > 9999) {
+            throw new IllegalArgumentException("Value out of bounds for BCD representation: " + decimal);
+        }
+
         int bcd = 0;
         int shift = 0;
-        while (binary > 0) {
-            int digit = binary % 10; // Extract the last decimal digit
-            bcd |= (digit << (shift * 4)); // Shift the digit to the correct BCD position
-            binary /= 10; // Remove the last decimal digit
+        while (decimal > 0) {
+            int digit = decimal % 10;
+            bcd |= (digit << (shift * 4));
+            decimal /= 10;
             shift++;
         }
         return bcd;
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java b/src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java
index 85221d92ad42..727b07eb9065 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java
@@ -1,65 +1,85 @@
 package com.thealgorithms.bitmanipulation;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
-/**
- * Unit tests for the BcdConversion class.
- */
 public class BcdConversionTest {
 
-    /**
-     * Test the bcdToBinary method with a BCD number.
-     */
     @Test
-    public void testBcdToBinary() {
-        int binary = BcdConversion.bcdToBinary(0x1234);
-        assertEquals(1234, binary); // BCD 0x1234 should convert to binary 1234
+    public void testBcdToDecimal() {
+        int decimal = BcdConversion.bcdToDecimal(0x1234);
+        assertEquals(1234, decimal); // BCD 0x1234 should convert to decimal 1234
     }
 
-    /**
-     * Test the binaryToBcd method with a binary number.
-     */
     @Test
-    public void testBinaryToBcd() {
-        int bcd = BcdConversion.binaryToBcd(1234);
-        assertEquals(0x1234, bcd); // Binary 1234 should convert to BCD 0x1234
+    public void testDecimalToBcd() {
+        int bcd = BcdConversion.decimalToBcd(1234);
+        assertEquals(0x1234, bcd); // Decimal 1234 should convert to BCD 0x1234
     }
 
-    /**
-     * Test the bcdToBinary method with zero.
-     */
     @Test
-    public void testBcdToBinaryZero() {
-        int binary = BcdConversion.bcdToBinary(0x0);
-        assertEquals(0, binary); // BCD 0x0 should convert to binary 0
+    public void testBcdToDecimalZero() {
+        int decimal = BcdConversion.bcdToDecimal(0x0);
+        assertEquals(0, decimal); // BCD 0x0 should convert to decimal 0
     }
 
-    /**
-     * Test the binaryToBcd method with zero.
-     */
     @Test
-    public void testBinaryToBcdZero() {
-        int bcd = BcdConversion.binaryToBcd(0);
-        assertEquals(0x0, bcd); // Binary 0 should convert to BCD 0x0
+    public void testDecimalToBcdZero() {
+        int bcd = BcdConversion.decimalToBcd(0);
+        assertEquals(0x0, bcd); // Decimal 0 should convert to BCD 0x0
     }
 
-    /**
-     * Test the bcdToBinary method with a single digit BCD number.
-     */
     @Test
-    public void testBcdToBinarySingleDigit() {
-        int binary = BcdConversion.bcdToBinary(0x7);
-        assertEquals(7, binary); // BCD 0x7 should convert to binary 7
+    public void testBcdToDecimalSingleDigit() {
+        int decimal = BcdConversion.bcdToDecimal(0x7);
+        assertEquals(7, decimal); // BCD 0x7 should convert to decimal 7
     }
 
-    /**
-     * Test the binaryToBcd method with a single digit binary number.
-     */
     @Test
-    public void testBinaryToBcdSingleDigit() {
-        int bcd = BcdConversion.binaryToBcd(7);
-        assertEquals(0x7, bcd); // Binary 7 should convert to BCD 0x7
+    public void testDecimalToBcdSingleDigit() {
+        int bcd = BcdConversion.decimalToBcd(7);
+        assertEquals(0x7, bcd); // Decimal 7 should convert to BCD 0x7
+    }
+
+    @Test
+    public void testBcdToDecimalMaxValue() {
+        int decimal = BcdConversion.bcdToDecimal(0x9999);
+        assertEquals(9999, decimal); // BCD 0x9999 should convert to decimal 9999
+    }
+
+    @Test
+    public void testDecimalToBcdMaxValue() {
+        int bcd = BcdConversion.decimalToBcd(9999);
+        assertEquals(0x9999, bcd); // Decimal 9999 should convert to BCD 0x9999
+    }
+
+    @Test
+    public void testBcdToDecimalInvalidHighDigit() {
+        // Testing invalid BCD input where one of the digits is > 9
+        assertThrows(IllegalArgumentException.class, () -> {
+            BcdConversion.bcdToDecimal(0x123A); // Invalid BCD, 'A' is not a valid digit
+        });
+    }
+
+    @Test
+    public void testDecimalToBcdInvalidValue() {
+        // Testing conversion for numbers greater than 9999, which cannot be represented in BCD
+        assertThrows(IllegalArgumentException.class, () -> {
+            BcdConversion.decimalToBcd(10000); // 10000 is too large for BCD representation
+        });
+    }
+
+    @Test
+    public void testBcdToDecimalLeadingZeroes() {
+        int decimal = BcdConversion.bcdToDecimal(0x0234);
+        assertEquals(234, decimal); // BCD 0x0234 should convert to decimal 234, ignoring leading zero
+    }
+
+    @Test
+    public void testDecimalToBcdLeadingZeroes() {
+        int bcd = BcdConversion.decimalToBcd(234);
+        assertEquals(0x0234, bcd); // Decimal 234 should convert to BCD 0x0234
     }
 }

From 9b52ac9633c5f58087c2ad7ac8af4a44009cea2b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 13 Oct 2024 17:00:27 +0530
Subject: [PATCH 0536/1338] feat: Add `IPConverter` new algorithm with Junit
 tests (#5750)

---
 DIRECTORY.md                                  |  2 +
 .../conversions/IPConverter.java              | 58 +++++++++++++++++++
 .../conversions/IPConverterTest.java          | 30 ++++++++++
 3 files changed, 90 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/IPConverter.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/IPConverterTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index d9beaadcba4d..32a084d92833 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -94,6 +94,7 @@
             * [HexToOct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexToOct.java)
             * [IntegerToEnglish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java)
             * [IntegerToRoman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java)
+            * [IPConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IPConverter.java)
             * [OctalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToBinary.java)
             * [OctalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java)
             * [OctalToHexadecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java)
@@ -727,6 +728,7 @@
             * [HexToOctTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexToOctTest.java)
             * [IntegerToEnglishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java)
             * [IntegerToRomanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java)
+            * [IPConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IPConverterTest.java)
             * [OctalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java)
             * [OctalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java)
             * [OctalToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
diff --git a/src/main/java/com/thealgorithms/conversions/IPConverter.java b/src/main/java/com/thealgorithms/conversions/IPConverter.java
new file mode 100644
index 000000000000..765cb0201dd5
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/IPConverter.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.conversions;
+
+/**
+ * Converts an IPv4 address to its binary equivalent and vice-versa.
+ * IP to Binary: Converts an IPv4 address to its binary equivalent.
+ * Example: 127.3.4.5 -> 01111111.00000011.00000100.00000101
+ *
+ * Binary to IP: Converts a binary equivalent to an IPv4 address.
+ * Example: 01111111.00000011.00000100.00000101 -> 127.3.4.5
+ *
+ * @author Hardvan
+ */
+public final class IPConverter {
+    private IPConverter() {
+    }
+
+    /**
+     * Converts an IPv4 address to its binary equivalent.
+     * @param ip The IPv4 address to convert.
+     * @return The binary equivalent of the IPv4 address.
+     */
+    public static String ipToBinary(String ip) {
+        StringBuilder binary = new StringBuilder();
+        for (String octet : ip.split("\\.")) {
+            binary.append(octetToBinary(Integer.parseInt(octet))).append(".");
+        }
+        return binary.substring(0, binary.length() - 1);
+    }
+
+    /**
+     * Converts a single octet to its 8-bit binary representation.
+     * @param octet The octet to convert (0-255).
+     * @return The 8-bit binary representation as a String.
+     */
+    private static String octetToBinary(int octet) {
+        char[] binary = {'0', '0', '0', '0', '0', '0', '0', '0'};
+        for (int i = 7; i >= 0; i--) {
+            if ((octet & 1) == 1) {
+                binary[i] = '1';
+            }
+            octet >>>= 1;
+        }
+        return new String(binary);
+    }
+
+    /**
+     * Converts a binary equivalent to an IPv4 address.
+     * @param binary The binary equivalent to convert.
+     * @return The IPv4 address of the binary equivalent.
+     */
+    public static String binaryToIP(String binary) {
+        StringBuilder ip = new StringBuilder();
+        for (String octet : binary.split("\\.")) {
+            ip.append(Integer.parseInt(octet, 2)).append(".");
+        }
+        return ip.substring(0, ip.length() - 1);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/IPConverterTest.java b/src/test/java/com/thealgorithms/conversions/IPConverterTest.java
new file mode 100644
index 000000000000..78c226a9237b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/IPConverterTest.java
@@ -0,0 +1,30 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class IPConverterTest {
+
+    private static String generateTestIP(int a, int b, int c, int d) {
+        return String.format("%d.%d.%d.%d", a, b, c, d);
+    }
+
+    private static String generateTestBinary(int a, int b, int c, int d) {
+        return String.format("%8s.%8s.%8s.%8s", Integer.toBinaryString(a), Integer.toBinaryString(b), Integer.toBinaryString(c), Integer.toBinaryString(d)).replace(' ', '0');
+    }
+
+    @Test
+    public void testIpToBinary() {
+        assertEquals(generateTestBinary(192, 168, 1, 1), IPConverter.ipToBinary(generateTestIP(192, 168, 1, 1)));
+        assertEquals(generateTestBinary(127, 3, 4, 5), IPConverter.ipToBinary(generateTestIP(127, 3, 4, 5)));
+        assertEquals(generateTestBinary(0, 0, 0, 0), IPConverter.ipToBinary(generateTestIP(0, 0, 0, 0)));
+    }
+
+    @Test
+    public void testBinaryToIP() {
+        assertEquals(generateTestIP(192, 168, 1, 1), IPConverter.binaryToIP(generateTestBinary(192, 168, 1, 1)));
+        assertEquals(generateTestIP(127, 3, 4, 5), IPConverter.binaryToIP(generateTestBinary(127, 3, 4, 5)));
+        assertEquals(generateTestIP(0, 0, 0, 0), IPConverter.binaryToIP(generateTestBinary(0, 0, 0, 0)));
+    }
+}

From ebc3cd22331f7d92df3df57d166ae13d4b933bdd Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 13 Oct 2024 17:16:10 +0200
Subject: [PATCH 0537/1338] style: resolve some `FCBL_FIELD_COULD_BE_LOCAL`
 warnings (#5764)

style: make simple fields local
---
 .../com/thealgorithms/datastructures/graphs/Cycles.java     | 3 +--
 src/main/java/com/thealgorithms/others/CRCAlgorithm.java    | 6 +-----
 src/main/java/com/thealgorithms/sorts/LinkListSort.java     | 4 +---
 .../java/com/thealgorithms/ciphers/a5/A5CipherTest.java     | 6 ++----
 .../thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java  | 3 +--
 5 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java b/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
index b67c5512e622..aea2b74bd13b 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java
@@ -6,7 +6,6 @@
 class Cycle {
 
     private final int nodes;
-    private final int edges;
     private int[][] adjacencyMatrix;
     private boolean[] visited;
     ArrayList<ArrayList<Integer>> cycles = new ArrayList<ArrayList<Integer>>();
@@ -16,7 +15,7 @@ class Cycle {
         System.out.print("Enter the no. of nodes: ");
         nodes = in.nextInt();
         System.out.print("Enter the no. of Edges: ");
-        edges = in.nextInt();
+        final int edges = in.nextInt();
 
         adjacencyMatrix = new int[nodes][nodes];
         visited = new boolean[nodes];
diff --git a/src/main/java/com/thealgorithms/others/CRCAlgorithm.java b/src/main/java/com/thealgorithms/others/CRCAlgorithm.java
index bfa8828e250b..284a290a5af8 100644
--- a/src/main/java/com/thealgorithms/others/CRCAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/CRCAlgorithm.java
@@ -25,8 +25,6 @@ public class CRCAlgorithm {
 
     private ArrayList<Integer> message;
 
-    private ArrayList<Integer> dividedMessage;
-
     private ArrayList<Integer> p;
 
     private Random randomGenerator;
@@ -44,7 +42,6 @@ public CRCAlgorithm(String str, int size, double ber) {
         messageChanged = false;
         message = new ArrayList<>();
         messSize = size;
-        dividedMessage = new ArrayList<>();
         p = new ArrayList<>();
         for (int i = 0; i < str.length(); i++) {
             p.add(Character.getNumericValue(str.charAt(i)));
@@ -103,7 +100,6 @@ public int getCorrectMess() {
     public void refactor() {
         messageChanged = false;
         message = new ArrayList<>();
-        dividedMessage = new ArrayList<>();
     }
 
     /**
@@ -156,7 +152,7 @@ public void divideMessageWithP(boolean check) {
                 }
             }
         }
-        dividedMessage = (ArrayList<Integer>) x.clone();
+        ArrayList<Integer> dividedMessage = (ArrayList<Integer>) x.clone();
         if (!check) {
             message.addAll(dividedMessage);
         } else {
diff --git a/src/main/java/com/thealgorithms/sorts/LinkListSort.java b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
index bf8910d94eae..800d78f36549 100644
--- a/src/main/java/com/thealgorithms/sorts/LinkListSort.java
+++ b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
@@ -259,14 +259,12 @@ static int count(Node head) {
 
 class Task2 {
 
-    private int[] a;
-
     public Node sortByHeapSort(Node head) {
         if (head == null || head.next == null) {
             return head;
         }
         int c = count(head);
-        a = new int[c];
+        int[] a = new int[c];
         // Array of size c is created
         int i = 0;
         for (Node ptr = head; ptr != null; ptr = ptr.next) {
diff --git a/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java b/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java
index aa725b644a86..011a1b521e31 100644
--- a/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java
@@ -9,14 +9,12 @@
 public class A5CipherTest {
 
     private A5Cipher a5Cipher;
-    private BitSet sessionKey;
-    private BitSet frameCounter;
 
     @BeforeEach
     void setUp() {
         // Initialize the session key and frame counter
-        sessionKey = BitSet.valueOf(new long[] {0b1010101010101010L});
-        frameCounter = BitSet.valueOf(new long[] {0b0000000000000001L});
+        final var sessionKey = BitSet.valueOf(new long[] {0b1010101010101010L});
+        final var frameCounter = BitSet.valueOf(new long[] {0b0000000000000001L});
         a5Cipher = new A5Cipher(sessionKey, frameCounter);
     }
 
diff --git a/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java b/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java
index bb18d4500fc0..c9b721f90b2d 100644
--- a/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java
@@ -12,7 +12,6 @@
 public class A5KeyStreamGeneratorTest {
 
     private A5KeyStreamGenerator keyStreamGenerator;
-    private BitSet sessionKey;
     private BitSet frameCounter;
 
     @BeforeEach
@@ -20,7 +19,7 @@ void setUp() {
         keyStreamGenerator = new A5KeyStreamGenerator();
 
         // Initialize session key and frame counter for testing
-        sessionKey = BitSet.valueOf(new long[] {0b1010101010101010L}); // Example 16-bit key
+        final var sessionKey = BitSet.valueOf(new long[] {0b1010101010101010L}); // Example 16-bit key
         frameCounter = BitSet.valueOf(new long[] {0b0000000000000001L}); // Example 16-bit frame counter
         keyStreamGenerator.initialize(sessionKey, frameCounter);
     }

From c301fec0ac11acefb95a645c4f5cf259782ff48c Mon Sep 17 00:00:00 2001
From: Nishchal Gupta <44377133+nishchalgv1@users.noreply.github.com>
Date: Mon, 14 Oct 2024 00:08:01 +0530
Subject: [PATCH 0538/1338] style: enable `TodoComment` in checkstyle (#5785)

* style: enable TodoComment in checkstyle

* style: remove redundant blank line

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 checkstyle.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 4fc237d29c5a..d78724455af7 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -183,7 +183,7 @@
     <!-- See https://checkstyle.org/checks/misc/index.html -->
     <module name="ArrayTypeStyle"/>
     <!-- TODO <module name="FinalParameters"/> -->
-    <!-- TODO <module name="TodoComment"/> -->
+    <module name="TodoComment"/>
     <module name="UpperEll"/>
 
     <!-- https://checkstyle.org/filters/suppressionxpathfilter.html -->

From 213fd5a4931ba1cb74fed76ff97043ae34ff174b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 02:35:12 +0530
Subject: [PATCH 0539/1338] Add `NonPreemptivePriorityScheduling` algorithm
 (#5535)

---
 DIRECTORY.md                                  |   2 +
 .../NonPreemptivePriorityScheduling.java      | 134 ++++++++++++++++++
 .../NonPreemptivePrioritySchedulingTest.java  |  70 +++++++++
 3 files changed, 206 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 32a084d92833..f1a531486de7 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -505,6 +505,7 @@
             * [HighestResponseRatioNextScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
             * [JobSchedulingWithDeadline](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java)
             * [MLFQScheduler](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java)
+            * [NonPreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
             * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
@@ -1039,6 +1040,7 @@
             * [HighestResponseRatioNextSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
             * [JobSchedulingWithDeadlineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java)
             * [MLFQSchedulerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java)
+            * [NonPreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
             * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java b/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java
new file mode 100644
index 000000000000..1d8e2c5160ff
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java
@@ -0,0 +1,134 @@
+package com.thealgorithms.scheduling;
+
+import java.util.LinkedList;
+import java.util.PriorityQueue;
+import java.util.Queue;
+
+/**
+ * This class implements the Non-Preemptive Priority Scheduling algorithm.
+ * Processes are executed in order of their priority. The process with the
+ * highest priority (lower priority number) is executed first,
+ * and once a process starts executing, it cannot be preempted.
+ */
+public final class NonPreemptivePriorityScheduling {
+
+    private NonPreemptivePriorityScheduling() {
+    }
+
+    /**
+     * Represents a process with an ID, burst time, priority, arrival time, and start time.
+     */
+    static class Process implements Comparable<Process> {
+        int id;
+        int arrivalTime;
+        int startTime;
+        int burstTime;
+        int priority;
+
+        /**
+         * Constructs a Process instance with the specified parameters.
+         *
+         * @param id          Unique identifier for the process
+         * @param arrivalTime Time when the process arrives in the system
+         * @param burstTime   Time required for the process execution
+         * @param priority    Priority of the process
+         */
+        Process(int id, int arrivalTime, int burstTime, int priority) {
+            this.id = id;
+            this.arrivalTime = arrivalTime;
+            this.startTime = -1;
+            this.burstTime = burstTime;
+            this.priority = priority;
+        }
+
+        /**
+         * Compare based on priority for scheduling. The process with the lowest
+         * priority is selected first.
+         * If two processes have the same priority, the one that arrives earlier is selected.
+         *
+         * @param other The other process to compare against
+         * @return A negative integer, zero, or a positive integer as this process
+         *         is less than, equal to, or greater than the specified process.
+         */
+        @Override
+        public int compareTo(Process other) {
+            if (this.priority == other.priority) {
+                return Integer.compare(this.arrivalTime, other.arrivalTime);
+            }
+            return Integer.compare(this.priority, other.priority);
+        }
+    }
+
+    /**
+     * Schedules processes based on their priority in a non-preemptive manner, considering their arrival times.
+     *
+     * @param processes Array of processes to be scheduled.
+     * @return Array of processes in the order they are executed.
+     */
+    public static Process[] scheduleProcesses(Process[] processes) {
+        PriorityQueue<Process> pq = new PriorityQueue<>();
+        Queue<Process> waitingQueue = new LinkedList<>();
+        int currentTime = 0;
+        int index = 0;
+        Process[] executionOrder = new Process[processes.length];
+
+        for (Process process : processes) {
+            waitingQueue.add(process);
+        }
+
+        while (!waitingQueue.isEmpty() || !pq.isEmpty()) {
+            // Add processes that have arrived to the priority queue
+            while (!waitingQueue.isEmpty() && waitingQueue.peek().arrivalTime <= currentTime) {
+                pq.add(waitingQueue.poll());
+            }
+
+            if (!pq.isEmpty()) {
+                Process currentProcess = pq.poll();
+                currentProcess.startTime = currentTime;
+                executionOrder[index++] = currentProcess;
+                currentTime += currentProcess.burstTime;
+            } else {
+                // If no process is ready, move to the next arrival time
+                currentTime = waitingQueue.peek().arrivalTime;
+            }
+        }
+
+        return executionOrder;
+    }
+
+    /**
+     * Calculates the average waiting time of the processes.
+     *
+     * @param processes      Array of processes.
+     * @param executionOrder Array of processes in execution order.
+     * @return Average waiting time.
+     */
+    public static double calculateAverageWaitingTime(Process[] processes, Process[] executionOrder) {
+        int totalWaitingTime = 0;
+
+        for (Process process : executionOrder) {
+            int waitingTime = process.startTime - process.arrivalTime;
+            totalWaitingTime += waitingTime;
+        }
+
+        return (double) totalWaitingTime / processes.length;
+    }
+
+    /**
+     * Calculates the average turn-around time of the processes.
+     *
+     * @param processes      Array of processes.
+     * @param executionOrder Array of processes in execution order.
+     * @return Average turn-around time.
+     */
+    public static double calculateAverageTurnaroundTime(Process[] processes, Process[] executionOrder) {
+        int totalTurnaroundTime = 0;
+
+        for (Process process : executionOrder) {
+            int turnaroundTime = process.startTime + process.burstTime - process.arrivalTime;
+            totalTurnaroundTime += turnaroundTime;
+        }
+
+        return (double) totalTurnaroundTime / processes.length;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java
new file mode 100644
index 000000000000..d28dcfeaaea3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java
@@ -0,0 +1,70 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class NonPreemptivePrioritySchedulingTest {
+
+    @Test
+    public void testCalculateAverageWaitingTime() {
+        NonPreemptivePriorityScheduling.Process[] processes = {new NonPreemptivePriorityScheduling.Process(1, 0, 10, 2), // id, arrivalTime, burstTime, priority
+            new NonPreemptivePriorityScheduling.Process(2, 0, 5, 1), new NonPreemptivePriorityScheduling.Process(3, 0, 8, 3)};
+        NonPreemptivePriorityScheduling.Process[] executionOrder = NonPreemptivePriorityScheduling.scheduleProcesses(processes);
+
+        double expectedAvgWaitingTime = (0 + 5 + 15) / 3.0; // Waiting times: 0 for P2, 5 for P1, 15 for P3
+        double actualAvgWaitingTime = NonPreemptivePriorityScheduling.calculateAverageWaitingTime(processes, executionOrder);
+
+        assertEquals(expectedAvgWaitingTime, actualAvgWaitingTime, 0.01, "Average waiting time should be calculated correctly.");
+    }
+
+    @Test
+    public void testCalculateAverageTurnaroundTime() {
+        NonPreemptivePriorityScheduling.Process[] processes = {new NonPreemptivePriorityScheduling.Process(1, 0, 10, 2), // id, arrivalTime, burstTime, priority
+            new NonPreemptivePriorityScheduling.Process(2, 0, 5, 1), new NonPreemptivePriorityScheduling.Process(3, 0, 8, 3)};
+
+        NonPreemptivePriorityScheduling.Process[] executionOrder = NonPreemptivePriorityScheduling.scheduleProcesses(processes);
+
+        double expectedAvgTurnaroundTime = (5 + 15 + 23) / 3.0; // Turnaround times: 5 for P2, 15 for P1, 23 for P3
+        double actualAvgTurnaroundTime = NonPreemptivePriorityScheduling.calculateAverageTurnaroundTime(processes, executionOrder);
+
+        assertEquals(expectedAvgTurnaroundTime, actualAvgTurnaroundTime, 0.01, "Average turnaround time should be calculated correctly.");
+    }
+
+    @Test
+    public void testStartTimeIsCorrect() {
+        NonPreemptivePriorityScheduling.Process[] processes = {new NonPreemptivePriorityScheduling.Process(1, 0, 10, 2), // id, arrivalTime, burstTime, priority
+            new NonPreemptivePriorityScheduling.Process(2, 0, 5, 1), new NonPreemptivePriorityScheduling.Process(3, 0, 8, 3)};
+        NonPreemptivePriorityScheduling.Process[] executionOrder = NonPreemptivePriorityScheduling.scheduleProcesses(processes);
+
+        // Check that the start time for each process is correctly set
+        assertEquals(0, executionOrder[0].startTime, "First process (P2) should start at time 0."); // Process 2 has the highest priority
+        assertEquals(5, executionOrder[1].startTime, "Second process (P1) should start at time 5.");
+        assertEquals(15, executionOrder[2].startTime, "Third process (P3) should start at time 15.");
+    }
+
+    @Test
+    public void testWithDelayedArrivalTimes() {
+        NonPreemptivePriorityScheduling.Process[] processes = {new NonPreemptivePriorityScheduling.Process(1, 0, 4, 1), // id, arrivalTime, burstTime, priority
+            new NonPreemptivePriorityScheduling.Process(2, 2, 3, 2), new NonPreemptivePriorityScheduling.Process(3, 4, 2, 3)};
+        NonPreemptivePriorityScheduling.Process[] executionOrder = NonPreemptivePriorityScheduling.scheduleProcesses(processes);
+
+        // Test the start times considering delayed arrivals
+        assertEquals(0, executionOrder[0].startTime, "First process (P1) should start at time 0.");
+        assertEquals(4, executionOrder[1].startTime, "Second process (P2) should start at time 4."); // After P1 finishes
+        assertEquals(7, executionOrder[2].startTime, "Third process (P3) should start at time 7."); // After P2 finishes
+    }
+
+    @Test
+    public void testWithGapsInArrivals() {
+        NonPreemptivePriorityScheduling.Process[] processes = {new NonPreemptivePriorityScheduling.Process(1, 0, 6, 2), // id, arrivalTime, burstTime, priority
+            new NonPreemptivePriorityScheduling.Process(2, 8, 4, 1), new NonPreemptivePriorityScheduling.Process(3, 12, 5, 3)};
+
+        NonPreemptivePriorityScheduling.Process[] executionOrder = NonPreemptivePriorityScheduling.scheduleProcesses(processes);
+
+        // Test the start times for processes with gaps in arrival times
+        assertEquals(0, executionOrder[0].startTime, "First process (P1) should start at time 0.");
+        assertEquals(8, executionOrder[1].startTime, "Second process (P2) should start at time 8."); // After P1 finishes, arrives at 8
+        assertEquals(12, executionOrder[2].startTime, "Third process (P3) should start at time 12."); // After P2 finishes, arrives at 12
+    }
+}

From 0020ab2a9a4b9490ab3c56b605f662feb9d0ac41 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 12:27:55 +0530
Subject: [PATCH 0540/1338] Add `LotteryScheduling` algorithm (#5656)

---
 DIRECTORY.md                                  |   2 +
 pom.xml                                       |   7 +
 .../scheduling/LotteryScheduling.java         | 141 ++++++++++++++++++
 .../scheduling/LotterySchedulingTest.java     |  64 ++++++++
 4 files changed, 214 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/LotteryScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/LotterySchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index f1a531486de7..19301ee333f5 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -504,6 +504,7 @@
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
             * [HighestResponseRatioNextScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
             * [JobSchedulingWithDeadline](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java)
+            * [LotteryScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/LotteryScheduling.java)
             * [MLFQScheduler](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java)
             * [NonPreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
@@ -1039,6 +1040,7 @@
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
             * [HighestResponseRatioNextSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
             * [JobSchedulingWithDeadlineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java)
+            * [LotterySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/LotterySchedulingTest.java)
             * [MLFQSchedulerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java)
             * [NonPreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
diff --git a/pom.xml b/pom.xml
index 673be6cd4e36..812f46c700ea 100644
--- a/pom.xml
+++ b/pom.xml
@@ -40,6 +40,13 @@
             <version>${assertj.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>5.14.1</version>
+            <scope>test</scope>
+        </dependency>
+
 
         <dependency>
             <groupId>org.junit.jupiter</groupId>
diff --git a/src/main/java/com/thealgorithms/scheduling/LotteryScheduling.java b/src/main/java/com/thealgorithms/scheduling/LotteryScheduling.java
new file mode 100644
index 000000000000..cea0c793d340
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/LotteryScheduling.java
@@ -0,0 +1,141 @@
+package com.thealgorithms.scheduling;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+/**
+ * The LotteryScheduling class implements the Lottery Scheduling algorithm, which is
+ * a probabilistic CPU scheduling algorithm. Processes are assigned tickets, and
+ * the CPU is allocated to a randomly selected process based on ticket count.
+ * Processes with more tickets have a higher chance of being selected.
+ */
+public final class LotteryScheduling {
+    private LotteryScheduling() {
+    }
+
+    private List<Process> processes;
+    private Random random;
+
+    /**
+     * Constructs a LotteryScheduling object with the provided list of processes.
+     *
+     * @param processes List of processes to be scheduled using Lottery Scheduling.
+     */
+    public LotteryScheduling(final List<Process> processes) {
+        this.processes = processes;
+        this.random = new Random();
+    }
+
+    /**
+     * Constructs a LotteryScheduling object with the provided list of processes and a Random object.
+     *
+     * @param processes List of processes to be scheduled using Lottery Scheduling.
+     * @param random    Random object used for generating random numbers.
+     */
+    public LotteryScheduling(final List<Process> processes, Random random) {
+        this.processes = processes;
+        this.random = random;
+    }
+
+    /**
+     * Schedules the processes using the Lottery Scheduling algorithm.
+     * Each process is assigned a certain number of tickets, and the algorithm randomly
+     * selects a process to execute based on ticket count. The method calculates the
+     * waiting time and turnaround time for each process and simulates their execution.
+     */
+    public List<Process> scheduleProcesses() {
+        int totalTickets = processes.stream().mapToInt(Process::getTickets).sum();
+        int currentTime = 0;
+        List<Process> executedProcesses = new ArrayList<>();
+
+        while (!processes.isEmpty()) {
+            int winningTicket = random.nextInt(totalTickets) + 1;
+            Process selectedProcess = selectProcessByTicket(winningTicket);
+
+            if (selectedProcess == null) {
+                // This should not happen in normal circumstances, but we'll handle it just in case
+                System.err.println("Error: No process selected. Recalculating total tickets.");
+                totalTickets = processes.stream().mapToInt(Process::getTickets).sum();
+                continue;
+            }
+
+            selectedProcess.setWaitingTime(currentTime);
+            currentTime += selectedProcess.getBurstTime();
+            selectedProcess.setTurnAroundTime(selectedProcess.getWaitingTime() + selectedProcess.getBurstTime());
+
+            executedProcesses.add(selectedProcess);
+            processes.remove(selectedProcess);
+
+            totalTickets = processes.stream().mapToInt(Process::getTickets).sum();
+        }
+
+        return executedProcesses;
+    }
+
+    /**
+     * Selects a process based on a winning ticket. The method iterates over the
+     * list of processes, and as the ticket sum accumulates, it checks if the
+     * current process holds the winning ticket.
+     *
+     * @param winningTicket The randomly generated ticket number that determines the selected process.
+     * @return The process associated with the winning ticket.
+     */
+    private Process selectProcessByTicket(int winningTicket) {
+        int ticketSum = 0;
+        for (Process process : processes) {
+            ticketSum += process.getTickets();
+            if (ticketSum >= winningTicket) {
+                return process;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * The Process class represents a process in the scheduling system. Each process has
+     * an ID, burst time (CPU time required for execution), number of tickets (used in
+     * lottery selection), waiting time, and turnaround time.
+     */
+    public static class Process {
+        private String processId;
+        private int burstTime;
+        private int tickets;
+        private int waitingTime;
+        private int turnAroundTime;
+
+        public Process(String processId, int burstTime, int tickets) {
+            this.processId = processId;
+            this.burstTime = burstTime;
+            this.tickets = tickets;
+        }
+
+        public String getProcessId() {
+            return processId;
+        }
+
+        public int getBurstTime() {
+            return burstTime;
+        }
+
+        public int getTickets() {
+            return tickets;
+        }
+
+        public int getWaitingTime() {
+            return waitingTime;
+        }
+
+        public void setWaitingTime(int waitingTime) {
+            this.waitingTime = waitingTime;
+        }
+
+        public int getTurnAroundTime() {
+            return turnAroundTime;
+        }
+
+        public void setTurnAroundTime(int turnAroundTime) {
+            this.turnAroundTime = turnAroundTime;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/LotterySchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/LotterySchedulingTest.java
new file mode 100644
index 000000000000..00fd8adcde27
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/LotterySchedulingTest.java
@@ -0,0 +1,64 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class LotterySchedulingTest {
+
+    private Random mockRandom;
+
+    @BeforeEach
+    public void setup() {
+        mockRandom = mock(Random.class);
+    }
+
+    @Test
+    public void testLotterySchedulingWithMockedRandom() {
+        List<LotteryScheduling.Process> processes = createProcesses();
+        LotteryScheduling lotteryScheduling = new LotteryScheduling(processes, mockRandom);
+
+        // Mock the sequence of random numbers (winning tickets)
+        // This sequence ensures that P1 (10 tickets), P3 (8 tickets), and P2 (5 tickets) are selected.
+        when(mockRandom.nextInt(23)).thenReturn(5, 18, 11); // winning tickets for P1, P3, and P2
+
+        List<LotteryScheduling.Process> executedProcesses = lotteryScheduling.scheduleProcesses();
+
+        assertEquals(3, executedProcesses.size());
+
+        // Assert the process execution order and properties
+        LotteryScheduling.Process process1 = executedProcesses.get(0);
+        assertEquals("P1", process1.getProcessId());
+        assertEquals(0, process1.getWaitingTime());
+        assertEquals(10, process1.getTurnAroundTime());
+
+        LotteryScheduling.Process process2 = executedProcesses.get(1);
+        assertEquals("P2", process2.getProcessId());
+        assertEquals(10, process2.getWaitingTime());
+        assertEquals(15, process2.getTurnAroundTime());
+
+        LotteryScheduling.Process process3 = executedProcesses.get(2);
+        assertEquals("P3", process3.getProcessId());
+        assertEquals(15, process3.getWaitingTime());
+        assertEquals(23, process3.getTurnAroundTime());
+    }
+
+    private List<LotteryScheduling.Process> createProcesses() {
+        LotteryScheduling.Process process1 = new LotteryScheduling.Process("P1", 10, 10); // 10 tickets
+        LotteryScheduling.Process process2 = new LotteryScheduling.Process("P2", 5, 5); // 5 tickets
+        LotteryScheduling.Process process3 = new LotteryScheduling.Process("P3", 8, 8); // 8 tickets
+
+        List<LotteryScheduling.Process> processes = new ArrayList<>();
+        processes.add(process1);
+        processes.add(process2);
+        processes.add(process3);
+
+        return processes;
+    }
+}

From 1e01ec5233559c93f9165698241a70a265e39ea3 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 12:32:55 +0530
Subject: [PATCH 0541/1338] Add `CountingInversions` algorithm (#5745)

---
 DIRECTORY.md                                  |   2 +
 .../divideandconquer/CountingInversions.java  | 101 ++++++++++++++++++
 .../CountingInversionsTest.java               |  32 ++++++
 3 files changed, 135 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/divideandconquer/CountingInversions.java
 create mode 100644 src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 19301ee333f5..0b34e106ba75 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -251,6 +251,7 @@
           * divideandconquer
             * [BinaryExponentiation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java)
             * [ClosestPair](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java)
+            * [CountingInversions](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/CountingInversions.java)
             * [MedianOfTwoSortedArrays](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArrays.java)
             * [SkylineAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java)
             * [StrassenMatrixMultiplication](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplication.java)
@@ -833,6 +834,7 @@
           * divideandconquer
             * [BinaryExponentiationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java)
             * [ClosestPairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java)
+            * [CountingInversionsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java)
             * [MedianOfTwoSortedArraysTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArraysTest.java)
             * [SkylineAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java)
             * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
diff --git a/src/main/java/com/thealgorithms/divideandconquer/CountingInversions.java b/src/main/java/com/thealgorithms/divideandconquer/CountingInversions.java
new file mode 100644
index 000000000000..15c8bc33b58f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/divideandconquer/CountingInversions.java
@@ -0,0 +1,101 @@
+package com.thealgorithms.divideandconquer;
+
+/**
+ * A utility class for counting the number of inversions in an array.
+ * <p>
+ * An inversion is a pair (i, j) such that i < j and arr[i] > arr[j].
+ * This class implements a divide-and-conquer approach, similar to merge sort,
+ * to count the number of inversions efficiently.
+ * <p>
+ * Time Complexity: O(n log n)
+ * Space Complexity: O(n) (due to temporary arrays during merge step)
+ *
+ * <p>Applications:
+ * - Used in algorithms related to sorting and permutation analysis.
+ * - Helps in determining how far an array is from being sorted.
+ * - Applicable in bioinformatics and signal processing.
+ *
+ * <p>This class cannot be instantiated, as it is intended to provide
+ * only static utility methods.
+ *
+ * @author Hardvan
+ */
+public final class CountingInversions {
+    private CountingInversions() {
+    }
+
+    /**
+     * Counts the number of inversions in the given array.
+     *
+     * @param arr The input array of integers.
+     * @return The total number of inversions in the array.
+     */
+    public static int countInversions(int[] arr) {
+        return mergeSortAndCount(arr, 0, arr.length - 1);
+    }
+
+    /**
+     * Recursively divides the array into two halves, sorts them, and counts
+     * the number of inversions. Uses a modified merge sort approach.
+     *
+     * @param arr  The input array.
+     * @param left The starting index of the current segment.
+     * @param right The ending index of the current segment.
+     * @return The number of inversions within the segment [left, right].
+     */
+    private static int mergeSortAndCount(int[] arr, int left, int right) {
+        if (left >= right) {
+            return 0;
+        }
+
+        int mid = left + (right - left) / 2;
+        int inversions = 0;
+
+        inversions += mergeSortAndCount(arr, left, mid);
+        inversions += mergeSortAndCount(arr, mid + 1, right);
+        inversions += mergeAndCount(arr, left, mid, right);
+        return inversions;
+    }
+
+    /**
+     * Merges two sorted subarrays and counts the cross-inversions between them.
+     * A cross-inversion occurs when an element from the right subarray is
+     * smaller than an element from the left subarray.
+     *
+     * @param arr The input array.
+     * @param left The starting index of the first subarray.
+     * @param mid The ending index of the first subarray and midpoint of the segment.
+     * @param right The ending index of the second subarray.
+     * @return The number of cross-inversions between the two subarrays.
+     */
+    private static int mergeAndCount(int[] arr, int left, int mid, int right) {
+        int[] leftArr = new int[mid - left + 1];
+        int[] rightArr = new int[right - mid];
+
+        System.arraycopy(arr, left, leftArr, 0, mid - left + 1);
+        System.arraycopy(arr, mid + 1, rightArr, 0, right - mid);
+
+        int i = 0;
+        int j = 0;
+        int k = left;
+        int inversions = 0;
+
+        while (i < leftArr.length && j < rightArr.length) {
+            if (leftArr[i] <= rightArr[j]) {
+                arr[k++] = leftArr[i++];
+            } else {
+                arr[k++] = rightArr[j++];
+                inversions += mid + 1 - left - i;
+            }
+        }
+
+        while (i < leftArr.length) {
+            arr[k++] = leftArr[i++];
+        }
+        while (j < rightArr.length) {
+            arr[k++] = rightArr[j++];
+        }
+
+        return inversions;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java b/src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java
new file mode 100644
index 000000000000..d12614d6fd06
--- /dev/null
+++ b/src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java
@@ -0,0 +1,32 @@
+package com.thealgorithms.divideandconquer;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class CountingInversionsTest {
+
+    @Test
+    public void testCountInversions() {
+        int[] arr = {2, 3, 8, 6, 1};
+        assertEquals(5, CountingInversions.countInversions(arr));
+    }
+
+    @Test
+    public void testNoInversions() {
+        int[] arr = {1, 2, 3, 4, 5};
+        assertEquals(0, CountingInversions.countInversions(arr));
+    }
+
+    @Test
+    public void testSingleElement() {
+        int[] arr = {1};
+        assertEquals(0, CountingInversions.countInversions(arr));
+    }
+
+    @Test
+    public void testAllInversions() {
+        int[] arr = {5, 4, 3, 2, 1};
+        assertEquals(10, CountingInversions.countInversions(arr));
+    }
+}

From 3401c003bd729ae19ddffb7567f25094b7596ffe Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 12:41:21 +0530
Subject: [PATCH 0542/1338] Add TilingProblem algorithm (#5746)

---
 DIRECTORY.md                                  |  2 +
 .../divideandconquer/TilingProblem.java       | 99 +++++++++++++++++++
 .../divideandconquer/TilingProblemTest.java   | 15 +++
 3 files changed, 116 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/divideandconquer/TilingProblem.java
 create mode 100644 src/test/java/com/thealgorithms/divideandconquer/TilingProblemTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0b34e106ba75..521961c117e2 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -255,6 +255,7 @@
             * [MedianOfTwoSortedArrays](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArrays.java)
             * [SkylineAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java)
             * [StrassenMatrixMultiplication](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplication.java)
+            * [TilingProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/TilingProblem.java)
           * dynamicprogramming
             * [BoardPath](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java)
             * [BoundaryFill](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java)
@@ -838,6 +839,7 @@
             * [MedianOfTwoSortedArraysTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArraysTest.java)
             * [SkylineAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java)
             * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
+            * [TilingProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/TilingProblemTest.java)
           * dynamicprogramming
             * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
             * [BoundaryFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java)
diff --git a/src/main/java/com/thealgorithms/divideandconquer/TilingProblem.java b/src/main/java/com/thealgorithms/divideandconquer/TilingProblem.java
new file mode 100644
index 000000000000..ff2e1678ab48
--- /dev/null
+++ b/src/main/java/com/thealgorithms/divideandconquer/TilingProblem.java
@@ -0,0 +1,99 @@
+package com.thealgorithms.divideandconquer;
+
+/**
+ * This class provides a solution to the Tiling Problem using divide-and-conquer.
+ * <p>
+ * The Tiling Problem involves filling a 2^n x 2^n board with a single missing
+ * square using L-shaped tiles (each tile covers exactly three squares).
+ * The algorithm recursively divides the board into four quadrants, places an
+ * L-shaped tile in the appropriate quadrant, and fills the remaining areas.
+ *
+ * <p>Applications:
+ * - Used in graphics and image processing.
+ * - Helpful in solving puzzles and tiling problems in competitive programming.
+ *
+ * @author Hardvan
+ */
+public final class TilingProblem {
+    private TilingProblem() {
+    }
+
+    /**
+     * A counter used to label the L-shaped tiles placed on the board.
+     */
+    private static int tile = 1;
+
+    /**
+     * A 2D array representing the board to be tiled.
+     */
+    private static int[][] board;
+
+    /**
+     * Solves the tiling problem for a 2^n x 2^n board with one missing square.
+     *
+     * @param size The size of the board (must be a power of 2).
+     * @param missingRow The row index of the missing square.
+     * @param missingCol The column index of the missing square.
+     * @return A 2D array representing the tiled board with L-shaped tiles.
+     */
+    public static int[][] solveTiling(int size, int missingRow, int missingCol) {
+        board = new int[size][size];
+        fillBoard(size, 0, 0, missingRow, missingCol);
+        return board;
+    }
+
+    /**
+     * Recursively fills the board with L-shaped tiles.
+     *
+     * <p>The board is divided into four quadrants. Depending on the location of
+     * the missing square, an L-shaped tile is placed at the center of the board
+     * to cover three of the four quadrants. The process is then repeated for
+     * each quadrant until the entire board is filled.
+     *
+     * @param size The current size of the sub-board.
+     * @param row The starting row index of the current sub-board.
+     * @param col The starting column index of the current sub-board.
+     * @param missingRow The row index of the missing square within the board.
+     * @param missingCol The column index of the missing square within the board.
+     */
+    private static void fillBoard(int size, int row, int col, int missingRow, int missingCol) {
+        if (size == 1) {
+            return;
+        }
+
+        int half = size / 2;
+        int t = tile++;
+
+        // Top-left quadrant
+        if (missingRow < row + half && missingCol < col + half) {
+            fillBoard(half, row, col, missingRow, missingCol);
+        } else {
+            board[row + half - 1][col + half - 1] = t;
+            fillBoard(half, row, col, row + half - 1, col + half - 1);
+        }
+
+        // Top-right quadrant
+        if (missingRow < row + half && missingCol >= col + half) {
+            fillBoard(half, row, col + half, missingRow, missingCol);
+        } else {
+            board[row + half - 1][col + half] = t;
+            fillBoard(half, row, col + half, row + half - 1, col + half);
+        }
+
+        // Bottom-left quadrant
+        if (missingRow >= row + half && missingCol < col + half) {
+            fillBoard(half, row + half, col, missingRow, missingCol);
+        } else {
+            board[row + half][col + half - 1] = t;
+            fillBoard(half, row + half, col, row + half, col + half - 1);
+        }
+
+        // Bottom-right quadrant
+        if (missingRow >= row + half && missingCol >= col + half) {
+            fillBoard(half, row + half, col + half, missingRow, missingCol);
+        } else {
+            board[row + half][col + half] = t;
+            fillBoard(half, row + half, col + half, row + half, col + half);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/divideandconquer/TilingProblemTest.java b/src/test/java/com/thealgorithms/divideandconquer/TilingProblemTest.java
new file mode 100644
index 000000000000..720e425f5ea3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/divideandconquer/TilingProblemTest.java
@@ -0,0 +1,15 @@
+package com.thealgorithms.divideandconquer;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class TilingProblemTest {
+
+    @Test
+    public void testTilingSize2() {
+        int[][] expected = {{1, 1}, {1, 0}};
+        int[][] result = TilingProblem.solveTiling(2, 1, 1);
+        assertArrayEquals(expected, result);
+    }
+}

From 40f2d0cf8ef6e1c458b2a07c918b1cbd9f91edb5 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 12:58:25 +0530
Subject: [PATCH 0543/1338] Add `MorseCodeConverter` algorithm (#5749)

---
 DIRECTORY.md                                  |  2 +
 .../conversions/MorseCodeConverter.java       | 98 +++++++++++++++++++
 .../conversions/MorseCodeConverterTest.java   | 19 ++++
 3 files changed, 119 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/MorseCodeConverter.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/MorseCodeConverterTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 521961c117e2..342aa37ae654 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -95,6 +95,7 @@
             * [IntegerToEnglish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java)
             * [IntegerToRoman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java)
             * [IPConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IPConverter.java)
+            * [MorseCodeConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/MorseCodeConverter.java)
             * [OctalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToBinary.java)
             * [OctalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java)
             * [OctalToHexadecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java)
@@ -733,6 +734,7 @@
             * [IntegerToEnglishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java)
             * [IntegerToRomanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java)
             * [IPConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IPConverterTest.java)
+            * [MorseCodeConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/MorseCodeConverterTest.java)
             * [OctalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java)
             * [OctalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java)
             * [OctalToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
diff --git a/src/main/java/com/thealgorithms/conversions/MorseCodeConverter.java b/src/main/java/com/thealgorithms/conversions/MorseCodeConverter.java
new file mode 100644
index 000000000000..a3973da0c586
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/MorseCodeConverter.java
@@ -0,0 +1,98 @@
+package com.thealgorithms.conversions;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Converts text to Morse code and vice-versa.
+ * Text to Morse code: Each letter is separated by a space and each word is separated by a pipe (|).
+ * Example: "HELLO WORLD" -> ".... . .-.. .-.. --- | .-- --- .-. .-.. -.."
+ *
+ * Morse code to text: Each letter is separated by a space and each word is separated by a pipe (|).
+ * Example: ".... . .-.. .-.. --- | .-- --- .-. .-.. -.." -> "HELLO WORLD"
+ *
+ * Applications: Used in radio communications and algorithmic challenges.
+ *
+ * @author Hardvan
+ */
+public final class MorseCodeConverter {
+    private MorseCodeConverter() {
+    }
+
+    private static final Map<Character, String> MORSE_MAP = new HashMap<>();
+    private static final Map<String, Character> REVERSE_MAP = new HashMap<>();
+
+    static {
+        MORSE_MAP.put('A', ".-");
+        MORSE_MAP.put('B', "-...");
+        MORSE_MAP.put('C', "-.-.");
+        MORSE_MAP.put('D', "-..");
+        MORSE_MAP.put('E', ".");
+        MORSE_MAP.put('F', "..-.");
+        MORSE_MAP.put('G', "--.");
+        MORSE_MAP.put('H', "....");
+        MORSE_MAP.put('I', "..");
+        MORSE_MAP.put('J', ".---");
+        MORSE_MAP.put('K', "-.-");
+        MORSE_MAP.put('L', ".-..");
+        MORSE_MAP.put('M', "--");
+        MORSE_MAP.put('N', "-.");
+        MORSE_MAP.put('O', "---");
+        MORSE_MAP.put('P', ".--.");
+        MORSE_MAP.put('Q', "--.-");
+        MORSE_MAP.put('R', ".-.");
+        MORSE_MAP.put('S', "...");
+        MORSE_MAP.put('T', "-");
+        MORSE_MAP.put('U', "..-");
+        MORSE_MAP.put('V', "...-");
+        MORSE_MAP.put('W', ".--");
+        MORSE_MAP.put('X', "-..-");
+        MORSE_MAP.put('Y', "-.--");
+        MORSE_MAP.put('Z', "--..");
+
+        // Build reverse map for decoding
+        MORSE_MAP.forEach((k, v) -> REVERSE_MAP.put(v, k));
+    }
+
+    /**
+     * Converts text to Morse code.
+     * Each letter is separated by a space and each word is separated by a pipe (|).
+     *
+     * @param text The text to convert to Morse code.
+     * @return The Morse code representation of the text.
+     */
+    public static String textToMorse(String text) {
+        StringBuilder morse = new StringBuilder();
+        String[] words = text.toUpperCase().split(" ");
+        for (int i = 0; i < words.length; i++) {
+            for (char c : words[i].toCharArray()) {
+                morse.append(MORSE_MAP.getOrDefault(c, "")).append(" ");
+            }
+            if (i < words.length - 1) {
+                morse.append("| ");
+            }
+        }
+        return morse.toString().trim();
+    }
+
+    /**
+     * Converts Morse code to text.
+     * Each letter is separated by a space and each word is separated by a pipe (|).
+     *
+     * @param morse The Morse code to convert to text.
+     * @return The text representation of the Morse code.
+     */
+    public static String morseToText(String morse) {
+        StringBuilder text = new StringBuilder();
+        String[] words = morse.split(" \\| ");
+        for (int i = 0; i < words.length; i++) {
+            for (String code : words[i].split(" ")) {
+                text.append(REVERSE_MAP.getOrDefault(code, '?'));
+            }
+            if (i < words.length - 1) {
+                text.append(" ");
+            }
+        }
+        return text.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/MorseCodeConverterTest.java b/src/test/java/com/thealgorithms/conversions/MorseCodeConverterTest.java
new file mode 100644
index 000000000000..153b632a0510
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/MorseCodeConverterTest.java
@@ -0,0 +1,19 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class MorseCodeConverterTest {
+
+    @Test
+    public void testTextToMorse() {
+        assertEquals(".- -...", MorseCodeConverter.textToMorse("AB"));
+        assertEquals(".... . .-.. .-.. --- | .-- --- .-. .-.. -..", MorseCodeConverter.textToMorse("HELLO WORLD"));
+    }
+
+    @Test
+    public void testMorseToText() {
+        assertEquals("AB", MorseCodeConverter.morseToText(".- -..."));
+    }
+}

From 5a710ea61f5682b7b99177f0bb6b73086681ce8d Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 13:09:58 +0530
Subject: [PATCH 0544/1338] Add `EndianConverter` algorithm (#5751)

---
 DIRECTORY.md                                  |  2 ++
 .../conversions/EndianConverter.java          | 23 +++++++++++++++++++
 .../conversions/EndianConverterTest.java      | 22 ++++++++++++++++++
 3 files changed, 47 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/EndianConverter.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/EndianConverterTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 342aa37ae654..eeb50764b688 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -89,6 +89,7 @@
             * [DecimalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java)
             * [DecimalToHexadecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToHexadecimal.java)
             * [DecimalToOctal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java)
+            * [EndianConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/EndianConverter.java)
             * [HexaDecimalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java)
             * [HexaDecimalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java)
             * [HexToOct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexToOct.java)
@@ -728,6 +729,7 @@
             * [DecimalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToBinaryTest.java)
             * [DecimalToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToHexadecimalTest.java)
             * [DecimalToOctalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToOctalTest.java)
+            * [EndianConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java)
             * [HexaDecimalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java)
             * [HexaDecimalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexaDecimalToDecimalTest.java)
             * [HexToOctTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexToOctTest.java)
diff --git a/src/main/java/com/thealgorithms/conversions/EndianConverter.java b/src/main/java/com/thealgorithms/conversions/EndianConverter.java
new file mode 100644
index 000000000000..d20d9d6d63b5
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/EndianConverter.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.conversions;
+
+/**
+ * Converts between big-endian and little-endian formats.
+ * Big-endian is the most significant byte first, while little-endian is the least significant byte first.
+ * Big-endian to little-endian: 0x12345678 -> 0x78563412
+ *
+ * Little-endian to big-endian: 0x12345678 -> 0x78563412
+ *
+ * @author Hardvan
+ */
+public final class EndianConverter {
+    private EndianConverter() {
+    }
+
+    public static int bigToLittleEndian(int value) {
+        return Integer.reverseBytes(value);
+    }
+
+    public static int littleToBigEndian(int value) {
+        return Integer.reverseBytes(value);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java b/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java
new file mode 100644
index 000000000000..9598dd163146
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class EndianConverterTest {
+
+    @Test
+    public void testBigToLittleEndian() {
+        assertEquals(0x78563412, EndianConverter.bigToLittleEndian(0x12345678));
+        assertEquals(0x00000000, EndianConverter.bigToLittleEndian(0x00000000));
+        assertEquals(0x00000001, EndianConverter.bigToLittleEndian(0x01000000));
+    }
+
+    @Test
+    public void testLittleToBigEndian() {
+        assertEquals(0x12345678, EndianConverter.littleToBigEndian(0x78563412));
+        assertEquals(0x00000000, EndianConverter.littleToBigEndian(0x00000000));
+        assertEquals(0x01000000, EndianConverter.littleToBigEndian(0x00000001));
+    }
+}

From e9b897bdeb76d89f26aa022f49ece843b03f2a86 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 13:14:58 +0530
Subject: [PATCH 0545/1338] Add `PhoneticAlphabetConverter` (#5752)

---
 DIRECTORY.md                                  |  2 +
 .../PhoneticAlphabetConverter.java            | 68 +++++++++++++++++++
 .../PhoneticAlphabetConverterTest.java        | 21 ++++++
 3 files changed, 91 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index eeb50764b688..80e61f587d66 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -100,6 +100,7 @@
             * [OctalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToBinary.java)
             * [OctalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java)
             * [OctalToHexadecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java)
+            * [PhoneticAlphabetConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java)
             * [RgbHsvConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java)
             * [RomanToInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/RomanToInteger.java)
             * [TurkishToLatinConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java)
@@ -740,6 +741,7 @@
             * [OctalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java)
             * [OctalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java)
             * [OctalToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
+            * [PhoneticAlphabetConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java)
             * [RomanToIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java)
             * [UnitConversionsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java)
             * [UnitsConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java)
diff --git a/src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java b/src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java
new file mode 100644
index 000000000000..bcea1862e99e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java
@@ -0,0 +1,68 @@
+package com.thealgorithms.conversions;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Converts text to the NATO phonetic alphabet.
+ * Examples:
+ * "ABC" -> "Alpha Bravo Charlie"
+ * "Hello" -> "Hotel Echo Lima Lima Oscar"
+ * "123" -> "One Two Three"
+ * "A1B2C3" -> "Alpha One Bravo Two Charlie Three"
+ *
+ * @author Hardvan
+ */
+public final class PhoneticAlphabetConverter {
+    private PhoneticAlphabetConverter() {
+    }
+
+    private static final Map<Character, String> PHONETIC_MAP = new HashMap<>();
+
+    static {
+        PHONETIC_MAP.put('A', "Alpha");
+        PHONETIC_MAP.put('B', "Bravo");
+        PHONETIC_MAP.put('C', "Charlie");
+        PHONETIC_MAP.put('D', "Delta");
+        PHONETIC_MAP.put('E', "Echo");
+        PHONETIC_MAP.put('F', "Foxtrot");
+        PHONETIC_MAP.put('G', "Golf");
+        PHONETIC_MAP.put('H', "Hotel");
+        PHONETIC_MAP.put('I', "India");
+        PHONETIC_MAP.put('J', "Juliett");
+        PHONETIC_MAP.put('K', "Kilo");
+        PHONETIC_MAP.put('L', "Lima");
+        PHONETIC_MAP.put('M', "Mike");
+        PHONETIC_MAP.put('N', "November");
+        PHONETIC_MAP.put('O', "Oscar");
+        PHONETIC_MAP.put('P', "Papa");
+        PHONETIC_MAP.put('Q', "Quebec");
+        PHONETIC_MAP.put('R', "Romeo");
+        PHONETIC_MAP.put('S', "Sierra");
+        PHONETIC_MAP.put('T', "Tango");
+        PHONETIC_MAP.put('U', "Uniform");
+        PHONETIC_MAP.put('V', "Victor");
+        PHONETIC_MAP.put('W', "Whiskey");
+        PHONETIC_MAP.put('X', "X-ray");
+        PHONETIC_MAP.put('Y', "Yankee");
+        PHONETIC_MAP.put('Z', "Zulu");
+        PHONETIC_MAP.put('0', "Zero");
+        PHONETIC_MAP.put('1', "One");
+        PHONETIC_MAP.put('2', "Two");
+        PHONETIC_MAP.put('3', "Three");
+        PHONETIC_MAP.put('4', "Four");
+        PHONETIC_MAP.put('5', "Five");
+        PHONETIC_MAP.put('6', "Six");
+        PHONETIC_MAP.put('7', "Seven");
+        PHONETIC_MAP.put('8', "Eight");
+        PHONETIC_MAP.put('9', "Nine");
+    }
+
+    public static String textToPhonetic(String text) {
+        StringBuilder phonetic = new StringBuilder();
+        for (char c : text.toUpperCase().toCharArray()) {
+            phonetic.append(PHONETIC_MAP.getOrDefault(c, String.valueOf(c))).append(" ");
+        }
+        return phonetic.toString().trim();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java b/src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java
new file mode 100644
index 000000000000..07847302c8d8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class PhoneticAlphabetConverterTest {
+
+    @Test
+    public void testTextToPhonetic() {
+        assertEquals("Alpha Bravo", PhoneticAlphabetConverter.textToPhonetic("AB"));
+        assertEquals("Alpha Bravo Charlie", PhoneticAlphabetConverter.textToPhonetic("ABC"));
+        assertEquals("Alpha One Bravo Two Charlie Three", PhoneticAlphabetConverter.textToPhonetic("A1B2C3"));
+        assertEquals("Hotel Echo Lima Lima Oscar", PhoneticAlphabetConverter.textToPhonetic("Hello"));
+        assertEquals("One Two Three", PhoneticAlphabetConverter.textToPhonetic("123"));
+        assertEquals("Alpha Bravo Charlie Delta Echo Foxtrot Golf Hotel India Juliett Kilo Lima Mike November Oscar Papa Quebec Romeo Sierra Tango Uniform Victor Whiskey X-ray Yankee Zulu Zero One Two Three Four Five Six Seven Eight Nine",
+            PhoneticAlphabetConverter.textToPhonetic("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"));
+        assertEquals("Alpha Bravo Charlie Delta Echo Foxtrot Golf Hotel India Juliett Kilo Lima Mike November Oscar Papa Quebec Romeo Sierra Tango Uniform Victor Whiskey X-ray Yankee Zulu Zero One Two Three Four Five Six Seven Eight Nine",
+            PhoneticAlphabetConverter.textToPhonetic("abcdefghijklmnopqrstuvwxyz0123456789"));
+    }
+}

From 85b3b1dfbef0bc704ab8000a2296e61a3f70ec2b Mon Sep 17 00:00:00 2001
From: xuyang471 <2621860014@qq.com>
Date: Mon, 14 Oct 2024 16:22:30 +0800
Subject: [PATCH 0546/1338] Add disk scheduling algorithms (#5748)

---
 .../CircularLookScheduling.java               | 80 ++++++++++++++++
 .../CircularScanScheduling.java               | 83 ++++++++++++++++
 .../diskscheduling/LookScheduling.java        | 95 +++++++++++++++++++
 .../diskscheduling/SSFScheduling.java         | 56 +++++++++++
 .../diskscheduling/ScanScheduling.java        | 82 ++++++++++++++++
 .../CircularLookSchedulingTest.java           | 54 +++++++++++
 .../CircularScanSchedulingTest.java           | 48 ++++++++++
 .../diskscheduling/LookSchedulingTest.java    | 67 +++++++++++++
 .../diskscheduling/SSFSchedulingTest.java     | 55 +++++++++++
 .../diskscheduling/ScanSchedulingTest.java    | 54 +++++++++++
 10 files changed, 674 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularLookScheduling.java
 create mode 100644 src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularScanScheduling.java
 create mode 100644 src/main/java/com/thealgorithms/scheduling/diskscheduling/LookScheduling.java
 create mode 100644 src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java
 create mode 100644 src/main/java/com/thealgorithms/scheduling/diskscheduling/ScanScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/diskscheduling/SSFSchedulingTest.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java

diff --git a/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularLookScheduling.java b/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularLookScheduling.java
new file mode 100644
index 000000000000..2230ecaf35a6
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularLookScheduling.java
@@ -0,0 +1,80 @@
+package com.thealgorithms.scheduling.diskscheduling;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Circular Look Scheduling (C-LOOK) is a disk scheduling algorithm similar to
+ * the C-SCAN algorithm but with a key difference. In C-LOOK, the disk arm also
+ * moves in one direction to service requests, but instead of going all the way
+ * to the end of the disk, it only goes as far as the furthest request in the
+ * current direction. After servicing the last request in the current direction,
+ * the arm immediately jumps back to the closest request on the other side without
+ * moving to the disk's extreme ends. This reduces the unnecessary movement of the
+ * disk arm, resulting in better performance compared to C-SCAN, while still
+ * maintaining fair wait times for requests.
+ */
+public class CircularLookScheduling {
+    private int currentPosition;
+    private boolean movingUp;
+    private final int maxCylinder;
+
+    public CircularLookScheduling(int startPosition, boolean movingUp, int maxCylinder) {
+        this.currentPosition = startPosition;
+        this.movingUp = movingUp;
+        this.maxCylinder = maxCylinder;
+    }
+
+    public List<Integer> execute(List<Integer> requests) {
+        List<Integer> result = new ArrayList<>();
+
+        // Filter and sort valid requests in both directions
+        List<Integer> upRequests = new ArrayList<>();
+        List<Integer> downRequests = new ArrayList<>();
+
+        for (int request : requests) {
+            if (request >= 0 && request < maxCylinder) {
+                if (request > currentPosition) {
+                    upRequests.add(request);
+                } else if (request < currentPosition) {
+                    downRequests.add(request);
+                }
+            }
+        }
+
+        Collections.sort(upRequests);
+        Collections.sort(downRequests);
+
+        if (movingUp) {
+            // Process all requests in the upward direction
+            result.addAll(upRequests);
+
+            // Jump to the lowest request and process all requests in the downward direction
+            result.addAll(downRequests);
+        } else {
+            // Process all requests in the downward direction (in reverse order)
+            Collections.reverse(downRequests);
+            result.addAll(downRequests);
+
+            // Jump to the highest request and process all requests in the upward direction (in reverse order)
+            Collections.reverse(upRequests);
+            result.addAll(upRequests);
+        }
+
+        // Update current position to the last processed request
+        if (!result.isEmpty()) {
+            currentPosition = result.get(result.size() - 1);
+        }
+
+        return result;
+    }
+
+    public int getCurrentPosition() {
+        return currentPosition;
+    }
+
+    public boolean isMovingUp() {
+        return movingUp;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularScanScheduling.java b/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularScanScheduling.java
new file mode 100644
index 000000000000..a31c3d99a89e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularScanScheduling.java
@@ -0,0 +1,83 @@
+package com.thealgorithms.scheduling.diskscheduling;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Circular Scan Scheduling (C-SCAN) is a disk scheduling algorithm that
+ * works by moving the disk arm in one direction to service requests until
+ * it reaches the end of the disk. Once it reaches the end, instead of reversing
+ * direction like in the SCAN algorithm, the arm moves back to the starting point
+ * without servicing any requests. This ensures a more uniform wait time for all
+ * requests, especially those near the disk edges. The algorithm then continues in
+ * the same direction, making it effective for balancing service time across all disk sectors.
+ */
+public class CircularScanScheduling {
+    private int currentPosition;
+    private boolean movingUp;
+    private final int diskSize;
+
+    public CircularScanScheduling(int startPosition, boolean movingUp, int diskSize) {
+        this.currentPosition = startPosition;
+        this.movingUp = movingUp;
+        this.diskSize = diskSize;
+    }
+
+    public List<Integer> execute(List<Integer> requests) {
+        if (requests.isEmpty()) {
+            return new ArrayList<>(); // Return empty list if there are no requests
+        }
+
+        List<Integer> sortedRequests = new ArrayList<>(requests);
+        Collections.sort(sortedRequests);
+
+        List<Integer> result = new ArrayList<>();
+
+        if (movingUp) {
+            // Moving up: process requests >= current position
+            for (int request : sortedRequests) {
+                if (request >= currentPosition && request < diskSize) {
+                    result.add(request);
+                }
+            }
+
+            // Jump to the smallest request and continue processing from the start
+            for (int request : sortedRequests) {
+                if (request < currentPosition) {
+                    result.add(request);
+                }
+            }
+        } else {
+            // Moving down: process requests <= current position in reverse order
+            for (int i = sortedRequests.size() - 1; i >= 0; i--) {
+                int request = sortedRequests.get(i);
+                if (request <= currentPosition) {
+                    result.add(request);
+                }
+            }
+
+            // Jump to the largest request and continue processing in reverse order
+            for (int i = sortedRequests.size() - 1; i >= 0; i--) {
+                int request = sortedRequests.get(i);
+                if (request > currentPosition) {
+                    result.add(request);
+                }
+            }
+        }
+
+        // Set final position to the last request processed
+        if (!result.isEmpty()) {
+            currentPosition = result.get(result.size() - 1);
+        }
+        return result;
+    }
+
+    public int getCurrentPosition() {
+        return currentPosition;
+    }
+
+    public boolean isMovingUp() {
+        return movingUp;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/scheduling/diskscheduling/LookScheduling.java b/src/main/java/com/thealgorithms/scheduling/diskscheduling/LookScheduling.java
new file mode 100644
index 000000000000..beba69b05eca
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/diskscheduling/LookScheduling.java
@@ -0,0 +1,95 @@
+package com.thealgorithms.scheduling.diskscheduling;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * https://en.wikipedia.org/wiki/LOOK_algorithm
+ * Look Scheduling algorithm implementation.
+ * The Look algorithm moves the disk arm to the closest request in the current direction,
+ * and once it processes all requests in that direction, it reverses the direction.
+ */
+public class LookScheduling {
+    private final int maxTrack;
+    private final int currentPosition;
+    private boolean movingUp;
+    private int farthestPosition;
+    public LookScheduling(int startPosition, boolean initialDirection, int maxTrack) {
+        this.currentPosition = startPosition;
+        this.movingUp = initialDirection;
+        this.maxTrack = maxTrack;
+    }
+
+    /**
+     * Executes the Look Scheduling algorithm on the given list of requests.
+     *
+     * @param requests List of disk requests.
+     * @return Order in which requests are processed.
+     */
+    public List<Integer> execute(List<Integer> requests) {
+        List<Integer> result = new ArrayList<>();
+        List<Integer> lower = new ArrayList<>();
+        List<Integer> upper = new ArrayList<>();
+
+        // Split requests into two lists based on their position relative to current position
+        for (int request : requests) {
+            if (request >= 0 && request < maxTrack) {
+                if (request < currentPosition) {
+                    lower.add(request);
+                } else {
+                    upper.add(request);
+                }
+            }
+        }
+
+        // Sort the requests
+        Collections.sort(lower);
+        Collections.sort(upper);
+
+        // Process the requests depending on the initial moving direction
+        if (movingUp) {
+            // Process requests in the upward direction
+            result.addAll(upper);
+            if (!upper.isEmpty()) {
+                farthestPosition = upper.get(upper.size() - 1);
+            }
+
+            // Reverse the direction and process downward
+            movingUp = false;
+            Collections.reverse(lower);
+            result.addAll(lower);
+            if (!lower.isEmpty()) {
+                farthestPosition = Math.max(farthestPosition, lower.get(0));
+            }
+        } else {
+            // Process requests in the downward direction
+            Collections.reverse(lower);
+            result.addAll(lower);
+            if (!lower.isEmpty()) {
+                farthestPosition = lower.get(0);
+            }
+
+            // Reverse the direction and process upward
+            movingUp = true;
+            result.addAll(upper);
+            if (!upper.isEmpty()) {
+                farthestPosition = Math.max(farthestPosition, upper.get(upper.size() - 1));
+            }
+        }
+
+        return result;
+    }
+
+    public int getCurrentPosition() {
+        return currentPosition;
+    }
+
+    public boolean isMovingUp() {
+        return movingUp;
+    }
+
+    public int getFarthestPosition() {
+        return farthestPosition;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java b/src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java
new file mode 100644
index 000000000000..30838821a2de
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.scheduling.diskscheduling;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ *https://en.wikipedia.org/wiki/Shortest_seek_first
+ * Shortest Seek First (SFF) Scheduling algorithm implementation.
+ * The SFF algorithm selects the next request to be serviced based on the shortest distance
+ * from the current position of the disk arm. It continuously evaluates all pending requests
+ * and chooses the one that requires the least amount of movement to service.
+ *
+ * This approach minimizes the average seek time, making it efficient in terms of response
+ * time for individual requests. However, it may lead to starvation for requests located
+ * further away from the current position of the disk arm.
+ *
+ * The SFF algorithm is particularly effective in systems where quick response time
+ * is crucial, as it ensures that the most accessible requests are prioritized for servicing.
+ */
+public class SSFScheduling {
+    private int currentPosition;
+
+    public SSFScheduling(int currentPosition) {
+        this.currentPosition = currentPosition;
+    }
+
+    public List<Integer> execute(List<Integer> requests) {
+        List<Integer> result = new ArrayList<>(requests);
+        List<Integer> orderedRequests = new ArrayList<>();
+
+        while (!result.isEmpty()) {
+            int closest = findClosest(result);
+            orderedRequests.add(closest);
+            result.remove(Integer.valueOf(closest));
+            currentPosition = closest;
+        }
+        return orderedRequests;
+    }
+
+    private int findClosest(List<Integer> requests) {
+        int minDistance = Integer.MAX_VALUE;
+        int closest = -1;
+        for (int request : requests) {
+            int distance = Math.abs(currentPosition - request);
+            if (distance < minDistance) {
+                minDistance = distance;
+                closest = request;
+            }
+        }
+        return closest;
+    }
+
+    public int getCurrentPosition() {
+        return currentPosition;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/scheduling/diskscheduling/ScanScheduling.java b/src/main/java/com/thealgorithms/scheduling/diskscheduling/ScanScheduling.java
new file mode 100644
index 000000000000..2c4fa7844a12
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/diskscheduling/ScanScheduling.java
@@ -0,0 +1,82 @@
+package com.thealgorithms.scheduling.diskscheduling;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * https://en.wikipedia.org/wiki/Elevator_algorithm
+ * SCAN Scheduling algorithm implementation.
+ * The SCAN algorithm moves the disk arm towards one end of the disk, servicing all requests
+ * along the way until it reaches the end. Once it reaches the end, it reverses direction
+ * and services the requests on its way back.
+ *
+ * This algorithm ensures that all requests are serviced in a fair manner,
+ * while minimizing the seek time for requests located close to the current position
+ * of the disk arm.
+ *
+ * The SCAN algorithm is particularly useful in environments with a large number of
+ * disk requests, as it reduces the overall movement of the disk arm compared to
+ */
+public class ScanScheduling {
+    private int headPosition;
+    private int diskSize;
+    private boolean movingUp;
+
+    public ScanScheduling(int headPosition, boolean movingUp, int diskSize) {
+        this.headPosition = headPosition;
+        this.movingUp = movingUp;
+        this.diskSize = diskSize;
+    }
+
+    public List<Integer> execute(List<Integer> requests) {
+        // If the request list is empty, return an empty result
+        if (requests.isEmpty()) {
+            return new ArrayList<>();
+        }
+
+        List<Integer> result = new ArrayList<>();
+        List<Integer> left = new ArrayList<>();
+        List<Integer> right = new ArrayList<>();
+
+        // Separate requests into those smaller than the current head position and those larger
+        for (int request : requests) {
+            if (request < headPosition) {
+                left.add(request);
+            } else {
+                right.add(request);
+            }
+        }
+
+        // Sort the requests
+        Collections.sort(left);
+        Collections.sort(right);
+
+        // Simulate the disk head movement
+        if (movingUp) {
+            // Head moving upward, process right-side requests first
+            result.addAll(right);
+            // After reaching the end of the disk, reverse direction and process left-side requests
+            result.add(diskSize - 1); // Simulate the head reaching the end of the disk
+            Collections.reverse(left);
+            result.addAll(left);
+        } else {
+            // Head moving downward, process left-side requests first
+            Collections.reverse(left);
+            result.addAll(left);
+            // After reaching the start of the disk, reverse direction and process right-side requests
+            result.add(0); // Simulate the head reaching the start of the disk
+            result.addAll(right);
+        }
+
+        return result;
+    }
+
+    public int getHeadPosition() {
+        return headPosition;
+    }
+
+    public boolean isMovingUp() {
+        return movingUp;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java
new file mode 100644
index 000000000000..ae04e725cde5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.scheduling.diskscheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class CircularLookSchedulingTest {
+
+    @Test
+    public void testCircularLookSchedulingMovingUp() {
+        CircularLookScheduling scheduling = new CircularLookScheduling(50, true, 200);
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+        List<Integer> expected = Arrays.asList(55, 58, 90, 150, 160, 18, 39);
+
+        List<Integer> result = scheduling.execute(requests);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCircularLookSchedulingMovingDown() {
+        CircularLookScheduling scheduling = new CircularLookScheduling(50, false, 200);
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+        List<Integer> expected = Arrays.asList(39, 18, 160, 150, 90, 58, 55);
+
+        List<Integer> result = scheduling.execute(requests);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCircularLookSchedulingEmptyRequests() {
+        CircularLookScheduling scheduling = new CircularLookScheduling(50, true, 200);
+        List<Integer> requests = Arrays.asList();
+        List<Integer> expected = Arrays.asList();
+
+        List<Integer> result = scheduling.execute(requests);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCircularLookSchedulingPrintStatus() {
+        CircularLookScheduling scheduling = new CircularLookScheduling(50, true, 200);
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+        List<Integer> result = scheduling.execute(requests);
+
+        // Print the final status
+        System.out.println("Final CircularLookScheduling Position: " + scheduling.getCurrentPosition());
+        System.out.println("CircularLookScheduling Moving Up: " + scheduling.isMovingUp());
+
+        // Print the order of request processing
+        System.out.println("Request Order: " + result);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java
new file mode 100644
index 000000000000..06bd53c0b392
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.scheduling.diskscheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class CircularScanSchedulingTest {
+
+    @Test
+    public void testCircularScanSchedulingMovingUp() {
+        CircularScanScheduling circularScan = new CircularScanScheduling(50, true, 200);
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+        List<Integer> expectedOrder = Arrays.asList(55, 58, 90, 150, 160, 18, 39);
+
+        List<Integer> result = circularScan.execute(requests);
+        assertEquals(expectedOrder, result);
+
+        System.out.println("Final CircularScan Position: " + circularScan.getCurrentPosition());
+        System.out.println("CircularScan Moving Up: " + circularScan.isMovingUp());
+        System.out.println("Request Order: " + result);
+    }
+
+    @Test
+    public void testCircularScanSchedulingMovingDown() {
+        CircularScanScheduling circularScan = new CircularScanScheduling(50, false, 200);
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+        List<Integer> expectedOrder = Arrays.asList(39, 18, 160, 150, 90, 58, 55);
+
+        List<Integer> result = circularScan.execute(requests);
+        assertEquals(expectedOrder, result);
+
+        System.out.println("Final CircularScan Position: " + circularScan.getCurrentPosition());
+        System.out.println("CircularScan Moving Down: " + circularScan.isMovingUp());
+        System.out.println("Request Order: " + result);
+    }
+
+    @Test
+    public void testCircularScanSchedulingEmptyRequests() {
+        CircularScanScheduling circularScan = new CircularScanScheduling(50, true, 200);
+        List<Integer> requests = Arrays.asList();
+        List<Integer> expectedOrder = Arrays.asList();
+
+        List<Integer> result = circularScan.execute(requests);
+        assertEquals(expectedOrder, result);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java
new file mode 100644
index 000000000000..91acc4837243
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java
@@ -0,0 +1,67 @@
+package com.thealgorithms.scheduling.diskscheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class LookSchedulingTest {
+
+    @Test
+    public void testLookSchedulingMovingUp() {
+        LookScheduling lookScheduling = new LookScheduling(50, true, 200);
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+        List<Integer> expected = Arrays.asList(55, 58, 90, 150, 160, 39, 18);
+
+        List<Integer> result = lookScheduling.execute(requests);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLookSchedulingMovingDown() {
+        LookScheduling lookScheduling = new LookScheduling(50, false, 200);
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+        List<Integer> expected = Arrays.asList(39, 18, 55, 58, 90, 150, 160);
+
+        List<Integer> result = lookScheduling.execute(requests);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLookSchedulingEmptyRequests() {
+        LookScheduling lookScheduling = new LookScheduling(50, true, 200);
+        List<Integer> requests = Arrays.asList();
+        List<Integer> expected = Arrays.asList();
+
+        List<Integer> result = lookScheduling.execute(requests);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testLookSchedulingCurrentPosition() {
+        LookScheduling lookScheduling = new LookScheduling(50, true, 200);
+
+        // Testing current position remains unchanged after scheduling.
+        assertEquals(50, lookScheduling.getCurrentPosition());
+    }
+
+    @Test
+    public void testLookSchedulingPrintStatus() {
+        LookScheduling lookScheduling = new LookScheduling(50, true, 200);
+
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+
+        List<Integer> result = lookScheduling.execute(requests);
+
+        List<Integer> expectedOrder = Arrays.asList(55, 58, 90, 150, 160, 39, 18);
+        assertEquals(expectedOrder, result);
+
+        System.out.println("Final LookScheduling Position: " + lookScheduling.getCurrentPosition());
+        System.out.println("LookScheduling Moving Up: " + lookScheduling.isMovingUp());
+
+        System.out.println("Farthest Position Reached: " + lookScheduling.getFarthestPosition());
+
+        System.out.println("Request Order: " + result);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/diskscheduling/SSFSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/diskscheduling/SSFSchedulingTest.java
new file mode 100644
index 000000000000..0239b0117f1b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/diskscheduling/SSFSchedulingTest.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.scheduling.diskscheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class SSFSchedulingTest {
+
+    private SSFScheduling scheduler;
+
+    @BeforeEach
+    public void setUp() {
+        scheduler = new SSFScheduling(50);
+    }
+
+    @Test
+    public void testExecuteWithEmptyList() {
+        List<Integer> requests = new ArrayList<>();
+        List<Integer> result = scheduler.execute(requests);
+        assertTrue(result.isEmpty(), "Result should be empty for an empty request list.");
+    }
+
+    @Test
+    public void testExecuteWithSingleRequest() {
+        List<Integer> requests = new ArrayList<>(List.of(100));
+        List<Integer> result = scheduler.execute(requests);
+        assertEquals(List.of(100), result, "The only request should be served first.");
+    }
+
+    @Test
+    public void testExecuteWithMultipleRequests() {
+        List<Integer> requests = new ArrayList<>(List.of(10, 90, 60, 40, 30, 70));
+        List<Integer> result = scheduler.execute(requests);
+        assertEquals(List.of(60, 70, 90, 40, 30, 10), result, "Requests should be served in the shortest seek first order.");
+    }
+
+    @Test
+    public void testExecuteWithSameDistanceRequests() {
+        List<Integer> requests = new ArrayList<>(List.of(45, 55));
+        List<Integer> result = scheduler.execute(requests);
+        assertEquals(List.of(45, 55), result, "When distances are equal, requests should be served in the order they appear in the list.");
+    }
+
+    @Test
+    public void testGetCurrentPositionAfterExecution() {
+        List<Integer> requests = new ArrayList<>(List.of(10, 90, 60, 40, 30, 70));
+        scheduler.execute(requests);
+        int currentPosition = scheduler.getCurrentPosition();
+        assertEquals(10, currentPosition, "Current position should be the last request after execution.");
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java
new file mode 100644
index 000000000000..1dbcd4893cb9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.scheduling.diskscheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class ScanSchedulingTest {
+
+    @Test
+    public void testScanSchedulingMovingUp() {
+        ScanScheduling scanScheduling = new ScanScheduling(50, true, 200);
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+        List<Integer> expected = Arrays.asList(55, 58, 90, 150, 160, 199, 39, 18);
+
+        List<Integer> result = scanScheduling.execute(requests);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testScanSchedulingMovingDown() {
+        ScanScheduling scanScheduling = new ScanScheduling(50, false, 200);
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+        List<Integer> expected = Arrays.asList(39, 18, 0, 55, 58, 90, 150, 160);
+
+        List<Integer> result = scanScheduling.execute(requests);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testScanSchedulingEmptyRequests() {
+        ScanScheduling scanScheduling = new ScanScheduling(50, true, 200);
+        List<Integer> requests = Arrays.asList();
+        List<Integer> expected = Arrays.asList();
+
+        List<Integer> result = scanScheduling.execute(requests);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testScanScheduling() {
+        ScanScheduling scanScheduling = new ScanScheduling(50, true, 200);
+        List<Integer> requests = Arrays.asList(55, 58, 39, 18, 90, 160, 150);
+
+        List<Integer> result = scanScheduling.execute(requests);
+        List<Integer> expectedOrder = Arrays.asList(55, 58, 90, 150, 160, 199, 39, 18);
+        assertEquals(expectedOrder, result);
+
+        System.out.println("Final Head Position: " + scanScheduling.getHeadPosition());
+        System.out.println("Head Moving Up: " + scanScheduling.isMovingUp());
+        System.out.println("Request Order: " + result);
+    }
+}

From 9c76b30271535123ea30c0b39a46ccee6b302c6c Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 14:25:15 +0530
Subject: [PATCH 0547/1338] Add tests for `Convolution` (#5766)

---
 DIRECTORY.md                                  | 13 +++++++++
 .../thealgorithms/maths/ConvolutionTest.java  | 27 +++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/maths/ConvolutionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 80e61f587d66..f354913a05e8 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -505,6 +505,12 @@
           * Recursion
             * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java)
           * scheduling
+            * diskscheduling
+              * [CircularLookScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularLookScheduling.java)
+              * [CircularScanScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularScanScheduling.java)
+              * [LookScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/LookScheduling.java)
+              * [ScanScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/ScanScheduling.java)
+              * [SSFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java)
             * [EDFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/EDFScheduling.java)
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
             * [HighestResponseRatioNextScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
@@ -923,6 +929,7 @@
             * [CeilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CeilTest.java)
             * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
             * [CombinationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CombinationsTest.java)
+            * [ConvolutionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ConvolutionTest.java)
             * [CrossCorrelationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java)
             * [DeterminantOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DeterminantOfMatrixTest.java)
             * [DigitalRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DigitalRootTest.java)
@@ -1046,6 +1053,12 @@
           * Recursion
             * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java)
           * scheduling
+            * diskscheduling
+              * [CircularLookSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java)
+              * [CircularScanSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java)
+              * [LookSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java)
+              * [ScanSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java)
+              * [SSFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/SSFSchedulingTest.java)
             * [EDFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java)
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
             * [HighestResponseRatioNextSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
diff --git a/src/test/java/com/thealgorithms/maths/ConvolutionTest.java b/src/test/java/com/thealgorithms/maths/ConvolutionTest.java
new file mode 100644
index 000000000000..d57b3b3ca4e5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/ConvolutionTest.java
@@ -0,0 +1,27 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class ConvolutionTest {
+
+    record ConvolutionTestCase(String description, double[] signalA, double[] signalB, double[] expected) {
+    }
+
+    @ParameterizedTest(name = "{0}")
+    @MethodSource("provideTestCases")
+    void testConvolution(ConvolutionTestCase testCase) {
+        double[] result = Convolution.convolution(testCase.signalA, testCase.signalB);
+        assertArrayEquals(testCase.expected, result, 1e-9, testCase.description);
+    }
+
+    private static Stream<ConvolutionTestCase> provideTestCases() {
+        return Stream.of(new ConvolutionTestCase("Basic convolution", new double[] {1, 2, 3}, new double[] {4, 5, 6}, new double[] {4, 13, 28, 27, 18}), new ConvolutionTestCase("Convolution with zero elements", new double[] {0, 0, 0}, new double[] {1, 2, 3}, new double[] {0, 0, 0, 0, 0}),
+            new ConvolutionTestCase("Convolution with single element", new double[] {2}, new double[] {3}, new double[] {6}), new ConvolutionTestCase("Convolution with different sizes", new double[] {1, 2}, new double[] {3, 4, 5}, new double[] {3, 10, 13, 10}),
+            new ConvolutionTestCase("Convolution with negative values", new double[] {1, -2, 3}, new double[] {-1, 2, -3}, new double[] {-1, 4, -10, 12, -9}),
+            new ConvolutionTestCase("Convolution with large numbers", new double[] {1e6, 2e6}, new double[] {3e6, 4e6}, new double[] {3e12, 1e13, 8e12}));
+    }
+}

From e19378d56c5d3f741a6b8402e4c8815fb38a6f88 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 16:18:55 +0530
Subject: [PATCH 0548/1338] Add tests, remove `main` in `RangeInSortedArray`
 (#5778)

---
 DIRECTORY.md                                  |  1 +
 .../misc/RangeInSortedArray.java              |  9 -----
 .../misc/RangeInSortedArrayTest.java          | 35 +++++++++++++++++++
 3 files changed, 36 insertions(+), 9 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index f354913a05e8..c23cb4a3490f 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1018,6 +1018,7 @@
             * [MedianOfRunningArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java)
             * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java)
             * [PalindromeSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java)
+            * [RangeInSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java)
             * [TwoSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
           * others
             * [ArrayLeftRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java)
diff --git a/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java b/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
index 0dfc8ac32a6f..6d3caa1814b6 100644
--- a/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
+++ b/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
@@ -1,18 +1,9 @@
 package com.thealgorithms.misc;
 
-import java.util.Arrays;
-
 public final class RangeInSortedArray {
     private RangeInSortedArray() {
     }
 
-    public static void main(String[] args) {
-        // Testcases
-        assert Arrays.equals(sortedRange(new int[] {1, 2, 3, 3, 3, 4, 5}, 3), new int[] {2, 4});
-        assert Arrays.equals(sortedRange(new int[] {1, 2, 3, 3, 3, 4, 5}, 4), new int[] {5, 5});
-        assert Arrays.equals(sortedRange(new int[] {0, 1, 2}, 3), new int[] {-1, -1});
-    }
-
     // Get the 1st and last occurrence index of a number 'key' in a non-decreasing array 'nums'
     // Gives [-1, -1] in case element doesn't exist in array
     public static int[] sortedRange(int[] nums, int key) {
diff --git a/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java b/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java
new file mode 100644
index 000000000000..7630d3e78dc7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java
@@ -0,0 +1,35 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class RangeInSortedArrayTest {
+
+    @ParameterizedTest(name = "Test case {index}: {3}")
+    @MethodSource("provideSortedRangeTestCases")
+    void testSortedRange(int[] nums, int key, int[] expectedRange, String description) {
+        assertArrayEquals(expectedRange, RangeInSortedArray.sortedRange(nums, key), description);
+    }
+
+    private static Stream<Arguments> provideSortedRangeTestCases() {
+        return Stream.of(Arguments.of(new int[] {1, 2, 3, 3, 3, 4, 5}, 3, new int[] {2, 4}, "Range for key 3 with multiple occurrences"), Arguments.of(new int[] {1, 2, 3, 3, 3, 4, 5}, 4, new int[] {5, 5}, "Range for key 4 with single occurrence"),
+            Arguments.of(new int[] {0, 1, 2}, 3, new int[] {-1, -1}, "Range for non-existent key"), Arguments.of(new int[] {}, 1, new int[] {-1, -1}, "Range in empty array"), Arguments.of(new int[] {1, 1, 1, 2, 3, 4, 5, 5, 5}, 1, new int[] {0, 2}, "Range for key at start"),
+            Arguments.of(new int[] {1, 1, 1, 2, 3, 4, 5, 5, 5}, 5, new int[] {6, 8}, "Range for key at end"));
+    }
+
+    @ParameterizedTest(name = "Test case {index}: {3}")
+    @MethodSource("provideGetCountLessThanTestCases")
+    void testGetCountLessThan(int[] nums, int key, int expectedCount, String description) {
+        assertEquals(expectedCount, RangeInSortedArray.getCountLessThan(nums, key), description);
+    }
+
+    private static Stream<Arguments> provideGetCountLessThanTestCases() {
+        return Stream.of(Arguments.of(new int[] {1, 2, 3, 3, 4, 5}, 3, 4, "Count of elements less than existing key"), Arguments.of(new int[] {1, 2, 3, 3, 4, 5}, 4, 5, "Count of elements less than non-existing key"), Arguments.of(new int[] {1, 2, 2, 3}, 5, 4, "Count with all smaller elements"),
+            Arguments.of(new int[] {2, 3, 4, 5}, 1, 0, "Count with no smaller elements"), Arguments.of(new int[] {}, 1, 0, "Count in empty array"));
+    }
+}

From 8d8834987a4fe925fe2f5b2039dc37f9e63c1859 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 16:40:18 +0530
Subject: [PATCH 0549/1338] Add tests, remove `main` in `EulerMethod` (#5771)

---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/misc/MatrixTranspose.java   | 73 +++++--------------
 .../misc/MatrixTransposeTest.java             | 33 +++++++++
 3 files changed, 52 insertions(+), 55 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/misc/MatrixTransposeTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index c23cb4a3490f..b756b8d1c751 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1014,6 +1014,7 @@
             * [ColorContrastRatioTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java)
             * [InverseOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/InverseOfMatrixTest.java)
             * [MapReduceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MapReduceTest.java)
+            * [MatrixTransposeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MatrixTransposeTest.java)
             * [MedianOfMatrixtest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java)
             * [MedianOfRunningArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java)
             * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java)
diff --git a/src/main/java/com/thealgorithms/misc/MatrixTranspose.java b/src/main/java/com/thealgorithms/misc/MatrixTranspose.java
index 153cf4e9df99..743682780b01 100644
--- a/src/main/java/com/thealgorithms/misc/MatrixTranspose.java
+++ b/src/main/java/com/thealgorithms/misc/MatrixTranspose.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.misc;
 
-import java.util.Scanner;
-
 /**
  *
  *
@@ -22,62 +20,27 @@ public final class MatrixTranspose {
     private MatrixTranspose() {
     }
 
-    public static void main(String[] args) {
-        /*
-         * This is the main method
-         *
-         * @param args Unused.
-         *
-         * @return Nothing.
-         */
-        Scanner sc = new Scanner(System.in);
-        int i;
-        int j;
-        int row;
-        int column;
-        System.out.println("Enter the number of rows in the 2D matrix:");
-
-        /*
-         * Take input from user for how many rows to be print
-         */
-        row = sc.nextInt();
-
-        System.out.println("Enter the number of columns in the 2D matrix:");
-
-        /*
-         * Take input from user for how many coloumn to be print
-         */
-        column = sc.nextInt();
-        int[][] arr = new int[row][column];
-        System.out.println("Enter the elements");
-        for (i = 0; i < row; i++) {
-            for (j = 0; j < column; j++) {
-                arr[i][j] = sc.nextInt();
-            }
-        }
-
-        /*
-         * Print matrix before the Transpose in proper way
-         */
-        System.out.println("The matrix is:");
-        for (i = 0; i < row; i++) {
-            for (j = 0; j < column; j++) {
-                System.out.print(arr[i][j] + "\t");
-            }
-            System.out.print("\n");
+    /**
+     * Calculate the transpose of the given matrix.
+     *
+     * @param matrix The matrix to be transposed
+     * @throws IllegalArgumentException if the matrix is empty
+     * @throws NullPointerException     if the matrix is null
+     * @return The transposed matrix
+     */
+    public static int[][] transpose(int[][] matrix) {
+        if (matrix == null || matrix.length == 0) {
+            throw new IllegalArgumentException("Matrix is empty");
         }
 
-        /*
-         * Print matrix after the tranpose in proper way Transpose means Interchanging
-         * of rows wth column so we interchange the rows in next loop Thus at last
-         * matrix of transpose is obtained through user input...
-         */
-        System.out.println("The Transpose of the given matrix is:");
-        for (i = 0; i < column; i++) {
-            for (j = 0; j < row; j++) {
-                System.out.print(arr[j][i] + "\t");
+        int rows = matrix.length;
+        int cols = matrix[0].length;
+        int[][] transposedMatrix = new int[cols][rows];
+        for (int i = 0; i < cols; i++) {
+            for (int j = 0; j < rows; j++) {
+                transposedMatrix[i][j] = matrix[j][i];
             }
-            System.out.print("\n");
         }
+        return transposedMatrix;
     }
 }
diff --git a/src/test/java/com/thealgorithms/misc/MatrixTransposeTest.java b/src/test/java/com/thealgorithms/misc/MatrixTransposeTest.java
new file mode 100644
index 000000000000..cf668807b819
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/MatrixTransposeTest.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class MatrixTransposeTest {
+
+    private static Stream<Arguments> provideValidMatrixTestCases() {
+        return Stream.of(Arguments.of(new int[][] {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}, new int[][] {{1, 4, 7}, {2, 5, 8}, {3, 6, 9}}, "Transpose of square matrix"), Arguments.of(new int[][] {{1, 2}, {3, 4}, {5, 6}}, new int[][] {{1, 3, 5}, {2, 4, 6}}, "Transpose of rectangular matrix"),
+            Arguments.of(new int[][] {{1, 2, 3}}, new int[][] {{1}, {2}, {3}}, "Transpose of single-row matrix"), Arguments.of(new int[][] {{1}, {2}, {3}}, new int[][] {{1, 2, 3}}, "Transpose of single-column matrix"));
+    }
+
+    private static Stream<Arguments> provideInvalidMatrixTestCases() {
+        return Stream.of(Arguments.of(new int[0][0], "Empty matrix should throw IllegalArgumentException"), Arguments.of(null, "Null matrix should throw IllegalArgumentException"));
+    }
+
+    @ParameterizedTest(name = "Test case {index}: {2}")
+    @MethodSource("provideValidMatrixTestCases")
+    void testValidMatrixTranspose(int[][] input, int[][] expected, String description) {
+        assertArrayEquals(expected, MatrixTranspose.transpose(input), description);
+    }
+
+    @ParameterizedTest(name = "Test case {index}: {1}")
+    @MethodSource("provideInvalidMatrixTestCases")
+    void testInvalidMatrixTranspose(int[][] input, String description) {
+        assertThrows(IllegalArgumentException.class, () -> MatrixTranspose.transpose(input), description);
+    }
+}

From bcf4034ce58ed965d1d885e1b0bf85a920f57e2d Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 16:57:06 +0530
Subject: [PATCH 0550/1338] Add tests, remove `main` in `WordBoggle` (#5782)

---
 DIRECTORY.md                                  |  1 +
 .../com/thealgorithms/misc/WordBoggle.java    | 31 ----------
 .../thealgorithms/misc/WordBoggleTest.java    | 56 +++++++++++++++++++
 3 files changed, 57 insertions(+), 31 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/misc/WordBoggleTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b756b8d1c751..4c454088088b 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1021,6 +1021,7 @@
             * [PalindromeSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java)
             * [RangeInSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java)
             * [TwoSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
+            * [WordBoggleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/WordBoggleTest.java)
           * others
             * [ArrayLeftRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java)
             * [ArrayRightRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java)
diff --git a/src/main/java/com/thealgorithms/misc/WordBoggle.java b/src/main/java/com/thealgorithms/misc/WordBoggle.java
index 3eb0dc95ffb5..8b629d68209b 100644
--- a/src/main/java/com/thealgorithms/misc/WordBoggle.java
+++ b/src/main/java/com/thealgorithms/misc/WordBoggle.java
@@ -1,7 +1,6 @@
 package com.thealgorithms.misc;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -32,36 +31,6 @@ public static List<String> boggleBoard(char[][] board, String[] words) {
         return new ArrayList<>(finalWords);
     }
 
-    public static void main(String[] args) {
-        // Testcase
-        List<String> ans = new ArrayList<>(Arrays.asList("a", "boggle", "this", "NOTRE_PEATED", "is", "simple", "board"));
-        assert (boggleBoard(
-            new char[][] {
-                {'t', 'h', 'i', 's', 'i', 's', 'a'},
-                {'s', 'i', 'm', 'p', 'l', 'e', 'x'},
-                {'b', 'x', 'x', 'x', 'x', 'e', 'b'},
-                {'x', 'o', 'g', 'g', 'l', 'x', 'o'},
-                {'x', 'x', 'x', 'D', 'T', 'r', 'a'},
-                {'R', 'E', 'P', 'E', 'A', 'd', 'x'},
-                {'x', 'x', 'x', 'x', 'x', 'x', 'x'},
-                {'N', 'O', 'T', 'R', 'E', '_', 'P'},
-                {'x', 'x', 'D', 'E', 'T', 'A', 'E'},
-            },
-            new String[] {
-                "this",
-                "is",
-                "not",
-                "a",
-                "simple",
-                "test",
-                "boggle",
-                "board",
-                "REPEATED",
-                "NOTRE_PEATED",
-            })
-                    .equals(ans));
-    }
-
     public static void explore(int i, int j, char[][] board, TrieNode trieNode, boolean[][] visited, Set<String> finalWords) {
         if (visited[i][j]) {
             return;
diff --git a/src/test/java/com/thealgorithms/misc/WordBoggleTest.java b/src/test/java/com/thealgorithms/misc/WordBoggleTest.java
new file mode 100644
index 000000000000..2c79ec796565
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/WordBoggleTest.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class WordBoggleTest {
+    private char[][] board;
+
+    @BeforeEach
+    void setup() {
+        board = new char[][] {
+            {'t', 'h', 'i', 's', 'i', 's', 'a'},
+            {'s', 'i', 'm', 'p', 'l', 'e', 'x'},
+            {'b', 'x', 'x', 'x', 'x', 'e', 'b'},
+            {'x', 'o', 'g', 'g', 'l', 'x', 'o'},
+            {'x', 'x', 'x', 'D', 'T', 'r', 'a'},
+            {'R', 'E', 'P', 'E', 'A', 'd', 'x'},
+            {'x', 'x', 'x', 'x', 'x', 'x', 'x'},
+            {'N', 'O', 'T', 'R', 'E', '_', 'P'},
+            {'x', 'x', 'D', 'E', 'T', 'A', 'E'},
+        };
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testBoggleBoard(String[] words, List<String> expectedWords, String testDescription) {
+        List<String> result = WordBoggle.boggleBoard(board, words);
+        assertEquals(expectedWords.size(), result.size(), "Test failed for: " + testDescription);
+        assertTrue(expectedWords.containsAll(result), "Test failed for: " + testDescription);
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new String[] {"this", "is", "not", "a", "simple", "test", "boggle", "board", "REPEATED", "NOTRE_PEATED"}, Arrays.asList("this", "is", "a", "simple", "board", "boggle", "NOTRE_PEATED"), "All words"),
+            Arguments.of(new String[] {"xyz", "hello", "world"}, List.of(), "No matching words"), Arguments.of(new String[] {}, List.of(), "Empty words array"), Arguments.of(new String[] {"this", "this", "board", "board"}, Arrays.asList("this", "board"), "Duplicate words in input"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideSpecialCases")
+    void testBoggleBoardSpecialCases(char[][] specialBoard, String[] words, List<String> expectedWords, String testDescription) {
+        List<String> result = WordBoggle.boggleBoard(specialBoard, words);
+        assertEquals(expectedWords.size(), result.size(), "Test failed for: " + testDescription);
+        assertTrue(expectedWords.containsAll(result), "Test failed for: " + testDescription);
+    }
+
+    private static Stream<Arguments> provideSpecialCases() {
+        return Stream.of(Arguments.of(new char[0][0], new String[] {"this", "is", "a", "test"}, List.of(), "Empty board"));
+    }
+}

From 1dfa2e571bd3ad61056aca611911733918d5e359 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 23:21:59 +0530
Subject: [PATCH 0551/1338] feat: Add `ConvexHull` new algorithm with Junit
 tests (#5789)

---
 DIRECTORY.md                                  |   3 +
 .../thealgorithms/geometry/ConvexHull.java    | 116 ++++++++++++++++++
 .../thealgorithms/geometry/GrahamScan.java    |  90 --------------
 .../com/thealgorithms/geometry/Point.java     |  45 +++++++
 .../geometry/ConvexHullTest.java              |  40 ++++++
 .../geometry/GrahamScanTest.java              |   2 +-
 6 files changed, 205 insertions(+), 91 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/geometry/ConvexHull.java
 create mode 100644 src/main/java/com/thealgorithms/geometry/Point.java
 create mode 100644 src/test/java/com/thealgorithms/geometry/ConvexHullTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 4c454088088b..a1feab7bef2a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -304,7 +304,9 @@
             * [WildcardMatching](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java)
             * [WineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java)
           * geometry
+            * [ConvexHull](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/ConvexHull.java)
             * [GrahamScan](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/GrahamScan.java)
+            * [Point](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/Point.java)
           * greedyalgorithms
             * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
             * [BinaryAddition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java)
@@ -896,6 +898,7 @@
             * [WildcardMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java)
             * [WineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WineProblemTest.java)
           * geometry
+            * [ConvexHullTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java)
             * [GrahamScanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
           * greedyalgorithms
             * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
diff --git a/src/main/java/com/thealgorithms/geometry/ConvexHull.java b/src/main/java/com/thealgorithms/geometry/ConvexHull.java
new file mode 100644
index 000000000000..19cecdc3a3ab
--- /dev/null
+++ b/src/main/java/com/thealgorithms/geometry/ConvexHull.java
@@ -0,0 +1,116 @@
+package com.thealgorithms.geometry;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.TreeSet;
+
+/**
+ * A class providing algorithms to compute the convex hull of a set of points
+ * using brute-force and recursive methods.
+ *
+ * Convex hull: The smallest convex polygon that contains all the given points.
+ *
+ * Algorithms provided:
+ * 1. Brute-Force Method
+ * 2. Recursive (Divide-and-Conquer) Method
+ *
+ * @author Hardvan
+ */
+public final class ConvexHull {
+    private ConvexHull() {
+    }
+
+    private static boolean checkPointOrientation(Point i, Point j, Point k) {
+        int detK = Point.orientation(i, j, k);
+        if (detK > 0) {
+            return true; // pointsLeftOfIJ
+        } else if (detK < 0) {
+            return false; // pointsRightOfIJ
+        } else {
+            return k.compareTo(i) >= 0 && k.compareTo(j) <= 0;
+        }
+    }
+
+    public static List<Point> convexHullBruteForce(List<Point> points) {
+        Set<Point> convexSet = new TreeSet<>(Comparator.naturalOrder());
+
+        for (int i = 0; i < points.size() - 1; i++) {
+            for (int j = i + 1; j < points.size(); j++) {
+                boolean allPointsOnOneSide = true;
+                boolean leftSide = checkPointOrientation(points.get(i), points.get(j), points.get((i + 1) % points.size()));
+
+                for (int k = 0; k < points.size(); k++) {
+                    if (k != i && k != j && checkPointOrientation(points.get(i), points.get(j), points.get(k)) != leftSide) {
+                        allPointsOnOneSide = false;
+                        break;
+                    }
+                }
+
+                if (allPointsOnOneSide) {
+                    convexSet.add(points.get(i));
+                    convexSet.add(points.get(j));
+                }
+            }
+        }
+
+        return new ArrayList<>(convexSet);
+    }
+
+    public static List<Point> convexHullRecursive(List<Point> points) {
+        Collections.sort(points);
+        Set<Point> convexSet = new HashSet<>();
+        Point leftMostPoint = points.get(0);
+        Point rightMostPoint = points.get(points.size() - 1);
+
+        convexSet.add(leftMostPoint);
+        convexSet.add(rightMostPoint);
+
+        List<Point> upperHull = new ArrayList<>();
+        List<Point> lowerHull = new ArrayList<>();
+
+        for (int i = 1; i < points.size() - 1; i++) {
+            int det = Point.orientation(leftMostPoint, rightMostPoint, points.get(i));
+            if (det > 0) {
+                upperHull.add(points.get(i));
+            } else if (det < 0) {
+                lowerHull.add(points.get(i));
+            }
+        }
+
+        constructHull(upperHull, leftMostPoint, rightMostPoint, convexSet);
+        constructHull(lowerHull, rightMostPoint, leftMostPoint, convexSet);
+
+        List<Point> result = new ArrayList<>(convexSet);
+        Collections.sort(result);
+        return result;
+    }
+
+    private static void constructHull(List<Point> points, Point left, Point right, Set<Point> convexSet) {
+        if (!points.isEmpty()) {
+            Point extremePoint = null;
+            int extremePointDistance = Integer.MIN_VALUE;
+            List<Point> candidatePoints = new ArrayList<>();
+
+            for (Point p : points) {
+                int det = Point.orientation(left, right, p);
+                if (det > 0) {
+                    candidatePoints.add(p);
+                    if (det > extremePointDistance) {
+                        extremePointDistance = det;
+                        extremePoint = p;
+                    }
+                }
+            }
+
+            if (extremePoint != null) {
+                constructHull(candidatePoints, left, extremePoint, convexSet);
+                convexSet.add(extremePoint);
+                constructHull(candidatePoints, extremePoint, right, convexSet);
+            }
+        }
+    }
+}
diff --git a/src/main/java/com/thealgorithms/geometry/GrahamScan.java b/src/main/java/com/thealgorithms/geometry/GrahamScan.java
index 1a36137895e0..1a373cf315a2 100644
--- a/src/main/java/com/thealgorithms/geometry/GrahamScan.java
+++ b/src/main/java/com/thealgorithms/geometry/GrahamScan.java
@@ -2,7 +2,6 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Comparator;
 import java.util.Stack;
 
 /**
@@ -66,93 +65,4 @@ public GrahamScan(Point[] points) {
     public Iterable<Point> hull() {
         return new ArrayList<>(hull);
     }
-
-    public record Point(int x, int y) implements Comparable<Point> {
-
-        /**
-         * Default constructor
-         * @param x x-coordinate
-         * @param y y-coordinate
-         */
-        public Point {
-        }
-
-        /**
-         * @return the x-coordinate
-         */
-        @Override
-        public int x() {
-            return x;
-        }
-
-        /**
-         * @return the y-coordinate
-         */
-        @Override
-        public int y() {
-            return y;
-        }
-
-        /**
-         * Determines the orientation of the triplet (a, b, c).
-         *
-         * @param a The first point
-         * @param b The second point
-         * @param c The third point
-         * @return -1 if (a, b, c) is clockwise, 0 if collinear, +1 if counterclockwise
-         */
-        public static int orientation(Point a, Point b, Point c) {
-            int val = (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
-            return Integer.compare(val, 0);
-        }
-
-        /**
-         * Compares this point with another point.
-         *
-         * @param p2 The point to compare to
-         * @return A positive integer if this point is greater, a negative integer if less, or 0 if equal
-         */
-        @Override
-        public int compareTo(Point p2) {
-            int cmpY = Integer.compare(this.y, p2.y);
-            return cmpY != 0 ? cmpY : Integer.compare(this.x, p2.x);
-        }
-
-        /**
-         * Returns a comparator to sort points by their polar order relative to this point.
-         *
-         * @return A polar order comparator
-         */
-        public Comparator<Point> polarOrder() {
-            return new PolarOrder();
-        }
-
-        private final class PolarOrder implements Comparator<Point> {
-            @Override
-            public int compare(Point p1, Point p2) {
-                int dx1 = p1.x - x;
-                int dy1 = p1.y - y;
-                int dx2 = p2.x - x;
-                int dy2 = p2.y - y;
-
-                if (dy1 >= 0 && dy2 < 0) {
-                    return -1; // p1 above p2
-                } else if (dy2 >= 0 && dy1 < 0) {
-                    return 1; // p1 below p2
-                } else if (dy1 == 0 && dy2 == 0) { // Collinear and horizontal
-                    return Integer.compare(dx2, dx1);
-                } else {
-                    return -orientation(Point.this, p1, p2); // Compare orientation
-                }
-            }
-        }
-
-        /**
-         * @return A string representation of this point in the format (x, y)
-         */
-        @Override
-        public String toString() {
-            return String.format("(%d, %d)", x, y);
-        }
-    }
 }
diff --git a/src/main/java/com/thealgorithms/geometry/Point.java b/src/main/java/com/thealgorithms/geometry/Point.java
new file mode 100644
index 000000000000..564edb4ba7b6
--- /dev/null
+++ b/src/main/java/com/thealgorithms/geometry/Point.java
@@ -0,0 +1,45 @@
+package com.thealgorithms.geometry;
+
+import java.util.Comparator;
+
+public record Point(int x, int y) implements Comparable<Point> {
+
+    @Override
+    public int compareTo(Point other) {
+        int cmpY = Integer.compare(this.y, other.y);
+        return cmpY != 0 ? cmpY : Integer.compare(this.x, other.x);
+    }
+
+    @Override
+    public String toString() {
+        return String.format("(%d, %d)", x, y);
+    }
+
+    public Comparator<Point> polarOrder() {
+        return new PolarOrder();
+    }
+
+    public static int orientation(Point a, Point b, Point c) {
+        return Integer.compare((b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x), 0);
+    }
+
+    private final class PolarOrder implements Comparator<Point> {
+        @Override
+        public int compare(Point p1, Point p2) {
+            int dx1 = p1.x - x;
+            int dy1 = p1.y - y;
+            int dx2 = p2.x - x;
+            int dy2 = p2.y - y;
+
+            if (dy1 >= 0 && dy2 < 0) {
+                return -1; // p1 above p2
+            } else if (dy2 >= 0 && dy1 < 0) {
+                return 1; // p1 below p2
+            } else if (dy1 == 0 && dy2 == 0) { // Collinear and horizontal
+                return Integer.compare(dx2, dx1);
+            } else {
+                return -orientation(Point.this, p1, p2); // Compare orientation
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java b/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java
new file mode 100644
index 000000000000..e3e32e43c6de
--- /dev/null
+++ b/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java
@@ -0,0 +1,40 @@
+package com.thealgorithms.geometry;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class ConvexHullTest {
+
+    @Test
+    void testConvexHullBruteForce() {
+        List<Point> points = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 1));
+        List<Point> expected = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 1));
+        assertEquals(expected, ConvexHull.convexHullBruteForce(points));
+
+        points = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 0));
+        expected = Arrays.asList(new Point(0, 0), new Point(10, 0));
+        assertEquals(expected, ConvexHull.convexHullBruteForce(points));
+
+        points = Arrays.asList(new Point(0, 3), new Point(2, 2), new Point(1, 1), new Point(2, 1), new Point(3, 0), new Point(0, 0), new Point(3, 3), new Point(2, -1), new Point(2, -4), new Point(1, -3));
+        expected = Arrays.asList(new Point(2, -4), new Point(1, -3), new Point(0, 0), new Point(3, 0), new Point(0, 3), new Point(3, 3));
+        assertEquals(expected, ConvexHull.convexHullBruteForce(points));
+    }
+
+    @Test
+    void testConvexHullRecursive() {
+        List<Point> points = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 1));
+        List<Point> expected = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 1));
+        assertEquals(expected, ConvexHull.convexHullRecursive(points));
+
+        points = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 0));
+        expected = Arrays.asList(new Point(0, 0), new Point(10, 0));
+        assertEquals(expected, ConvexHull.convexHullRecursive(points));
+
+        points = Arrays.asList(new Point(0, 3), new Point(2, 2), new Point(1, 1), new Point(2, 1), new Point(3, 0), new Point(0, 0), new Point(3, 3), new Point(2, -1), new Point(2, -4), new Point(1, -3));
+        expected = Arrays.asList(new Point(2, -4), new Point(1, -3), new Point(0, 0), new Point(3, 0), new Point(0, 3), new Point(3, 3));
+        assertEquals(expected, ConvexHull.convexHullRecursive(points));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java b/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java
index e59cd6b860cc..622273881a27 100644
--- a/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java
+++ b/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java
@@ -7,7 +7,7 @@
 public class GrahamScanTest {
     @Test
     void testGrahamScan() {
-        GrahamScan.Point[] points = {new GrahamScan.Point(0, 3), new GrahamScan.Point(1, 1), new GrahamScan.Point(2, 2), new GrahamScan.Point(4, 4), new GrahamScan.Point(0, 0), new GrahamScan.Point(1, 2), new GrahamScan.Point(3, 1), new GrahamScan.Point(3, 3)};
+        Point[] points = {new Point(0, 3), new Point(1, 1), new Point(2, 2), new Point(4, 4), new Point(0, 0), new Point(1, 2), new Point(3, 1), new Point(3, 3)};
         String expectedResult = "[(0, 0), (3, 1), (4, 4), (0, 3)]";
 
         GrahamScan graham = new GrahamScan(points);

From 6ef1f7ca01823b8f533173a318727bd5b1f1e2e5 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 14 Oct 2024 23:26:05 +0530
Subject: [PATCH 0552/1338] Add tests, remove `main` in `ThreeSumProblem`
 (#5781)

---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/misc/ThreeSumProblem.java   | 19 -------
 .../misc/ThreeSumProblemTest.java             | 52 +++++++++++++++++++
 3 files changed, 53 insertions(+), 19 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a1feab7bef2a..265d1aeeb893 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1023,6 +1023,7 @@
             * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java)
             * [PalindromeSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java)
             * [RangeInSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java)
+            * [ThreeSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java)
             * [TwoSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
             * [WordBoggleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/WordBoggleTest.java)
           * others
diff --git a/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java b/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
index 1c5f4a440532..8ef10758ef80 100644
--- a/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
+++ b/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java
@@ -7,29 +7,10 @@
 import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.List;
-import java.util.Scanner;
 import java.util.Set;
 
 public class ThreeSumProblem {
 
-    public static void main(String[] args) {
-        Scanner scan = new Scanner(System.in);
-        System.out.print("Enter the target sum ");
-        int ts = scan.nextInt();
-        System.out.print("Enter the number of elements in the array ");
-        int n = scan.nextInt();
-        System.out.println("Enter all your array elements:");
-        int[] arr = new int[n];
-        for (int i = 0; i < n; i++) {
-            arr[i] = scan.nextInt();
-        }
-        ThreeSumProblem th = new ThreeSumProblem();
-        System.out.println("Brute Force Approach\n" + (th.bruteForce(arr, ts)) + "\n");
-        System.out.println("Two Pointer Approach\n" + (th.twoPointer(arr, ts)) + "\n");
-        System.out.println("Hashmap Approach\n" + (th.hashMap(arr, ts)));
-        scan.close();
-    }
-
     public List<List<Integer>> bruteForce(int[] nums, int target) {
         List<List<Integer>> arr = new ArrayList<List<Integer>>();
 
diff --git a/src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java b/src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java
new file mode 100644
index 000000000000..5353168216ec
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java
@@ -0,0 +1,52 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class ThreeSumProblemTest {
+
+    private ThreeSumProblem tsp;
+
+    @BeforeEach
+    public void setup() {
+        tsp = new ThreeSumProblem();
+    }
+
+    @ParameterizedTest
+    @MethodSource("bruteForceTestProvider")
+    public void testBruteForce(int[] nums, int target, List<List<Integer>> expected) {
+        assertEquals(expected, tsp.bruteForce(nums, target));
+    }
+
+    @ParameterizedTest
+    @MethodSource("twoPointerTestProvider")
+    public void testTwoPointer(int[] nums, int target, List<List<Integer>> expected) {
+        assertEquals(expected, tsp.twoPointer(nums, target));
+    }
+
+    @ParameterizedTest
+    @MethodSource("hashMapTestProvider")
+    public void testHashMap(int[] nums, int target, List<List<Integer>> expected) {
+        assertEquals(expected, tsp.hashMap(nums, target));
+    }
+
+    private static Stream<Arguments> bruteForceTestProvider() {
+        return Stream.of(Arguments.of(new int[] {1, 2, -3, 4, -2, -1}, 0, Arrays.asList(Arrays.asList(-3, 1, 2), Arrays.asList(-3, -1, 4))), Arguments.of(new int[] {1, 2, 3, 4, 5}, 50, new ArrayList<>()));
+    }
+
+    private static Stream<Arguments> twoPointerTestProvider() {
+        return Stream.of(Arguments.of(new int[] {0, -1, 2, -3, 1}, 0, Arrays.asList(Arrays.asList(-3, 1, 2), Arrays.asList(-1, 0, 1))), Arguments.of(new int[] {-5, -4, -3, -2, -1}, -10, Arrays.asList(Arrays.asList(-5, -4, -1), Arrays.asList(-5, -3, -2))));
+    }
+
+    private static Stream<Arguments> hashMapTestProvider() {
+        return Stream.of(Arguments.of(new int[] {1, 2, -1, -4, 3, 0}, 2, Arrays.asList(Arrays.asList(-1, 0, 3), Arrays.asList(-1, 1, 2))), Arguments.of(new int[] {5, 7, 9, 11}, 10, new ArrayList<>()), Arguments.of(new int[] {}, 0, new ArrayList<>()));
+    }
+}

From 3af4cfd7c8e83df8f7018d802c61f9c22296e729 Mon Sep 17 00:00:00 2001
From: Byte Bender <136265142+BYT-Bender@users.noreply.github.com>
Date: Tue, 15 Oct 2024 01:32:40 +0530
Subject: [PATCH 0553/1338] Add SumOfOddNumbers (#5730)

---
 .../thealgorithms/maths/SumOfOddNumbers.java  | 25 +++++++++++++++++
 .../maths/SumOfOddNumbersTest.java            | 28 +++++++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java
 create mode 100644 src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java

diff --git a/src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java b/src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java
new file mode 100644
index 000000000000..c0a1e782659a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java
@@ -0,0 +1,25 @@
+package com.thealgorithms.maths;
+
+/**
+ * This program calculates the sum of the first n odd numbers.
+ *
+ * https://www.cuemath.com/algebra/sum-of-odd-numbers/
+ */
+
+public final class SumOfOddNumbers {
+    private SumOfOddNumbers() {
+    }
+
+    /**
+     * Calculate sum of the first n odd numbers
+     *
+     * @param n the number of odd numbers to sum
+     * @return sum of the first n odd numbers
+     */
+    public static int sumOfFirstNOddNumbers(final int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("n must be non-negative.");
+        }
+        return n * n;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java b/src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java
new file mode 100644
index 000000000000..6470d7983888
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class SumOfOddNumbersTest {
+
+    @ParameterizedTest
+    @MethodSource("inputStream")
+    void sumOfFirstNOddNumbersTests(int expected, int input) {
+        Assertions.assertEquals(expected, SumOfOddNumbers.sumOfFirstNOddNumbers(input));
+    }
+
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of(1, 1), Arguments.of(4, 2), Arguments.of(9, 3), Arguments.of(16, 4), Arguments.of(25, 5), Arguments.of(100, 10));
+    }
+
+    @Test
+    public void testSumOfFirstNOddNumbersThrowsExceptionForNegativeInput() {
+        assertThrows(IllegalArgumentException.class, () -> SumOfOddNumbers.sumOfFirstNOddNumbers(-1));
+    }
+}

From 8886e0996a793d3a5573609a331c31709160ce4d Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 14 Oct 2024 22:46:28 +0200
Subject: [PATCH 0554/1338] style: include `OCP_OVERLY_CONCRETE_PARAMETER`
 (#5833)

---
 spotbugs-exclude.xml                                         | 3 ---
 .../java/com/thealgorithms/backtracking/CrosswordSolver.java | 3 ++-
 .../java/com/thealgorithms/datastructures/graphs/AStar.java  | 2 +-
 .../datastructures/graphs/EdmondsBlossomAlgorithm.java       | 2 +-
 .../datastructures/lists/MergeSortedArrayList.java           | 3 ++-
 src/main/java/com/thealgorithms/geometry/ConvexHull.java     | 3 ++-
 .../java/com/thealgorithms/maths/CircularConvolutionFFT.java | 3 ++-
 src/main/java/com/thealgorithms/maths/ConvolutionFFT.java    | 3 ++-
 src/main/java/com/thealgorithms/maths/FFT.java               | 3 ++-
 src/main/java/com/thealgorithms/maths/FFTBluestein.java      | 3 ++-
 src/main/java/com/thealgorithms/maths/Gaussian.java          | 3 ++-
 src/main/java/com/thealgorithms/maths/NthUglyNumber.java     | 3 ++-
 src/main/java/com/thealgorithms/misc/MedianOfMatrix.java     | 2 +-
 .../com/thealgorithms/misc/PalindromeSinglyLinkedList.java   | 5 ++---
 src/main/java/com/thealgorithms/others/KochSnowflake.java    | 3 ++-
 .../scheduling/PreemptivePriorityScheduling.java             | 3 ++-
 .../java/com/thealgorithms/scheduling/SJFScheduling.java     | 3 ++-
 .../scheduling/diskscheduling/SSFScheduling.java             | 3 ++-
 src/main/java/com/thealgorithms/sorts/BucketSort.java        | 2 +-
 src/main/java/com/thealgorithms/sorts/PatienceSort.java      | 2 +-
 src/main/java/com/thealgorithms/sorts/PigeonholeSort.java    | 2 +-
 src/main/java/com/thealgorithms/sorts/TreeSort.java          | 2 +-
 src/main/java/com/thealgorithms/strings/WordLadder.java      | 4 ++--
 .../datastructures/graphs/BoruvkaAlgorithmTest.java          | 2 +-
 .../datastructures/graphs/EdmondsBlossomAlgorithmTest.java   | 3 ++-
 src/test/java/com/thealgorithms/misc/WordBoggleTest.java     | 3 ++-
 .../scheduling/PreemptivePrioritySchedulingTest.java         | 3 ++-
 .../java/com/thealgorithms/searches/QuickSelectTest.java     | 3 ++-
 28 files changed, 46 insertions(+), 33 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index bfc7716730c3..14bc5dfe9439 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -87,9 +87,6 @@
         <Bug pattern="RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE" />
     </Match>
     <!-- fb-contrib -->
-    <Match>
-        <Bug pattern="OCP_OVERLY_CONCRETE_PARAMETER" />
-    </Match>
     <Match>
         <Bug pattern="LSC_LITERAL_STRING_COMPARISON" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java b/src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java
index cbd9f70f74f4..6bfb026c7de9 100644
--- a/src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java
+++ b/src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.backtracking;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 
 /**
@@ -95,7 +96,7 @@ public static void removeWord(char[][] puzzle, String word, int row, int col, bo
      * @param words  The list of words to be placed.
      * @return true if the crossword is solved, false otherwise.
      */
-    public static boolean solveCrossword(char[][] puzzle, List<String> words) {
+    public static boolean solveCrossword(char[][] puzzle, Collection<String> words) {
         // Create a mutable copy of the words list
         List<String> remainingWords = new ArrayList<>(words);
 
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java b/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java
index 460c05e04403..741caa59c5b5 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java
@@ -94,7 +94,7 @@ public int getEstimated() {
     }
 
     // Initializes the graph with edges defined in the input data
-    static void initializeGraph(Graph graph, ArrayList<Integer> data) {
+    static void initializeGraph(Graph graph, List<Integer> data) {
         for (int i = 0; i < data.size(); i += 4) {
             graph.addEdge(new Edge(data.get(i), data.get(i + 1), data.get(i + 2)));
         }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java
index 27ad96d71876..db716580d689 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java
@@ -30,7 +30,7 @@ private EdmondsBlossomAlgorithm() {
      * @param vertexCount The number of vertices in the graph.
      * @return A list of matched pairs of vertices.
      */
-    public static List<int[]> maximumMatching(List<int[]> edges, int vertexCount) {
+    public static List<int[]> maximumMatching(Iterable<int[]> edges, int vertexCount) {
         List<List<Integer>> graph = new ArrayList<>(vertexCount);
 
         // Initialize each vertex's adjacency list.
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java b/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java
index 99ab09f81c1c..e315c4236338 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.lists;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 
 /**
@@ -38,7 +39,7 @@ public static void main(String[] args) {
      * @param listB the second list to merge
      * @param listC the result list after merging
      */
-    public static void merge(List<Integer> listA, List<Integer> listB, List<Integer> listC) {
+    public static void merge(List<Integer> listA, List<Integer> listB, Collection<Integer> listC) {
         int pa = 0;
         /* the index of listA */
         int pb = 0;
diff --git a/src/main/java/com/thealgorithms/geometry/ConvexHull.java b/src/main/java/com/thealgorithms/geometry/ConvexHull.java
index 19cecdc3a3ab..17f400854c64 100644
--- a/src/main/java/com/thealgorithms/geometry/ConvexHull.java
+++ b/src/main/java/com/thealgorithms/geometry/ConvexHull.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.geometry;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashSet;
@@ -89,7 +90,7 @@ public static List<Point> convexHullRecursive(List<Point> points) {
         return result;
     }
 
-    private static void constructHull(List<Point> points, Point left, Point right, Set<Point> convexSet) {
+    private static void constructHull(Collection<Point> points, Point left, Point right, Set<Point> convexSet) {
         if (!points.isEmpty()) {
             Point extremePoint = null;
             int extremePointDistance = Integer.MIN_VALUE;
diff --git a/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java b/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java
index f7010acf452d..87fc5af57b8d 100644
--- a/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java
+++ b/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
 import java.util.ArrayList;
+import java.util.Collection;
 
 /**
  * Class for circular convolution of two discrete signals using the convolution
@@ -19,7 +20,7 @@ private CircularConvolutionFFT() {
      * @param x The signal to be padded.
      * @param newSize The new size of the signal.
      */
-    private static void padding(ArrayList<FFT.Complex> x, int newSize) {
+    private static void padding(Collection<FFT.Complex> x, int newSize) {
         if (x.size() < newSize) {
             int diff = newSize - x.size();
             for (int i = 0; i < diff; i++) {
diff --git a/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java b/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java
index ce35b02ca13b..ed1ba1bbefc3 100644
--- a/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java
+++ b/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
 import java.util.ArrayList;
+import java.util.Collection;
 
 /**
  * Class for linear convolution of two discrete signals using the convolution
@@ -19,7 +20,7 @@ private ConvolutionFFT() {
      * @param x The signal to be padded.
      * @param newSize The new size of the signal.
      */
-    private static void padding(ArrayList<FFT.Complex> x, int newSize) {
+    private static void padding(Collection<FFT.Complex> x, int newSize) {
         if (x.size() < newSize) {
             int diff = newSize - x.size();
             for (int i = 0; i < diff; i++) {
diff --git a/src/main/java/com/thealgorithms/maths/FFT.java b/src/main/java/com/thealgorithms/maths/FFT.java
index 7ca7543d7985..47605f010b22 100644
--- a/src/main/java/com/thealgorithms/maths/FFT.java
+++ b/src/main/java/com/thealgorithms/maths/FFT.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 
 /**
@@ -274,7 +275,7 @@ private static int reverseBits(int num, int log2n) {
      *
      * @param x The ArrayList to be padded.
      */
-    private static void paddingPowerOfTwo(ArrayList<Complex> x) {
+    private static void paddingPowerOfTwo(Collection<Complex> x) {
         int n = 1;
         int oldSize = x.size();
         while (n < oldSize) {
diff --git a/src/main/java/com/thealgorithms/maths/FFTBluestein.java b/src/main/java/com/thealgorithms/maths/FFTBluestein.java
index 388de6fed3eb..7a03c20cc642 100644
--- a/src/main/java/com/thealgorithms/maths/FFTBluestein.java
+++ b/src/main/java/com/thealgorithms/maths/FFTBluestein.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * Class for calculating the Fast Fourier Transform (FFT) of a discrete signal
@@ -25,7 +26,7 @@ private FFTBluestein() {
      * IFFT of signal x.
      * @param inverse True if you want to find the inverse FFT.
      */
-    public static void fftBluestein(ArrayList<FFT.Complex> x, boolean inverse) {
+    public static void fftBluestein(List<FFT.Complex> x, boolean inverse) {
         int n = x.size();
         int bnSize = 2 * n - 1;
         int direction = inverse ? -1 : 1;
diff --git a/src/main/java/com/thealgorithms/maths/Gaussian.java b/src/main/java/com/thealgorithms/maths/Gaussian.java
index 255a84d13854..1e02579757cc 100644
--- a/src/main/java/com/thealgorithms/maths/Gaussian.java
+++ b/src/main/java/com/thealgorithms/maths/Gaussian.java
@@ -1,12 +1,13 @@
 package com.thealgorithms.maths;
 
 import java.util.ArrayList;
+import java.util.List;
 
 public final class Gaussian {
     private Gaussian() {
     }
 
-    public static ArrayList<Double> gaussian(int matSize, ArrayList<Double> matrix) {
+    public static ArrayList<Double> gaussian(int matSize, List<Double> matrix) {
         int i;
         int j = 0;
 
diff --git a/src/main/java/com/thealgorithms/maths/NthUglyNumber.java b/src/main/java/com/thealgorithms/maths/NthUglyNumber.java
index 90507701332f..6484026c14dd 100644
--- a/src/main/java/com/thealgorithms/maths/NthUglyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/NthUglyNumber.java
@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Map;
 import org.apache.commons.lang3.tuple.MutablePair;
 
 /**
@@ -64,7 +65,7 @@ private void updatePositions() {
         }
     }
 
-    private long computeCandidate(final MutablePair<Integer, Integer> entry) {
+    private long computeCandidate(final Map.Entry<Integer, Integer> entry) {
         return entry.getKey() * uglyNumbers.get(entry.getValue());
     }
 
diff --git a/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java b/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
index d4ddffe8ddd7..edeedbbee540 100644
--- a/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
+++ b/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
@@ -13,7 +13,7 @@ public final class MedianOfMatrix {
     private MedianOfMatrix() {
     }
 
-    public static int median(List<List<Integer>> matrix) {
+    public static int median(Iterable<List<Integer>> matrix) {
         // Flatten the matrix into a 1D list
         List<Integer> linear = new ArrayList<>();
         for (List<Integer> row : matrix) {
diff --git a/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java b/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
index 8af8a9b030e1..51dc099ba32e 100644
--- a/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
+++ b/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
@@ -1,6 +1,5 @@
 package com.thealgorithms.misc;
 
-import com.thealgorithms.datastructures.lists.SinglyLinkedList;
 import java.util.Stack;
 
 /**
@@ -15,8 +14,8 @@ public final class PalindromeSinglyLinkedList {
     private PalindromeSinglyLinkedList() {
     }
 
-    public static boolean isPalindrome(final SinglyLinkedList linkedList) {
-        Stack<Integer> linkedListValues = new Stack<>();
+    public static boolean isPalindrome(final Iterable linkedList) {
+        var linkedListValues = new Stack<>();
 
         for (final var x : linkedList) {
             linkedListValues.push(x);
diff --git a/src/main/java/com/thealgorithms/others/KochSnowflake.java b/src/main/java/com/thealgorithms/others/KochSnowflake.java
index 0e2600a7d72f..46b8edb1f177 100644
--- a/src/main/java/com/thealgorithms/others/KochSnowflake.java
+++ b/src/main/java/com/thealgorithms/others/KochSnowflake.java
@@ -7,6 +7,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.List;
 import javax.imageio.ImageIO;
 
 /**
@@ -125,7 +126,7 @@ public static BufferedImage getKochSnowflake(int imageWidth, int steps) {
      * applied.
      * @return The transformed vectors after the iteration-step.
      */
-    private static ArrayList<Vector2> iterationStep(ArrayList<Vector2> vectors) {
+    private static ArrayList<Vector2> iterationStep(List<Vector2> vectors) {
         ArrayList<Vector2> newVectors = new ArrayList<Vector2>();
         for (int i = 0; i < vectors.size() - 1; i++) {
             Vector2 startVector = vectors.get(i);
diff --git a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
index 27d85a94d6f5..66c99661d13d 100644
--- a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java
@@ -2,6 +2,7 @@
 
 import com.thealgorithms.devutils.entities.ProcessDetails;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Comparator;
 import java.util.List;
 import java.util.PriorityQueue;
@@ -15,7 +16,7 @@ public class PreemptivePriorityScheduling {
     protected final List<ProcessDetails> processes;
     protected final List<String> ganttChart;
 
-    public PreemptivePriorityScheduling(List<ProcessDetails> processes) {
+    public PreemptivePriorityScheduling(Collection<ProcessDetails> processes) {
         this.processes = new ArrayList<>(processes);
         this.ganttChart = new ArrayList<>();
     }
diff --git a/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java b/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
index ca2144e4924f..6d105003e68f 100644
--- a/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
@@ -2,6 +2,7 @@
 
 import com.thealgorithms.devutils.entities.ProcessDetails;
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * Implementation of Shortest Job First Algorithm: The algorithm allows the waiting process with the
@@ -87,7 +88,7 @@ public void scheduleProcesses() {
      * @return returns the process' with the shortest burst time OR NULL if there are no ready
      *     processes
      */
-    private ProcessDetails findShortestJob(ArrayList<ProcessDetails> readyProcesses) {
+    private ProcessDetails findShortestJob(List<ProcessDetails> readyProcesses) {
         if (readyProcesses.isEmpty()) {
             return null;
         }
diff --git a/src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java b/src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java
index 30838821a2de..261c1a388393 100644
--- a/src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.scheduling.diskscheduling;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 
 /**
@@ -24,7 +25,7 @@ public SSFScheduling(int currentPosition) {
         this.currentPosition = currentPosition;
     }
 
-    public List<Integer> execute(List<Integer> requests) {
+    public List<Integer> execute(Collection<Integer> requests) {
         List<Integer> result = new ArrayList<>(requests);
         List<Integer> orderedRequests = new ArrayList<>();
 
diff --git a/src/main/java/com/thealgorithms/sorts/BucketSort.java b/src/main/java/com/thealgorithms/sorts/BucketSort.java
index a6901ac339ac..62c5e929593b 100644
--- a/src/main/java/com/thealgorithms/sorts/BucketSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BucketSort.java
@@ -79,7 +79,7 @@ private <T extends Comparable<T>> void distributeElementsIntoBuckets(T[] array,
      * @param <T> the type of elements in the array
      * @return the sorted array
      */
-    private <T extends Comparable<T>> T[] concatenateBuckets(List<List<T>> buckets, T[] array) {
+    private <T extends Comparable<T>> T[] concatenateBuckets(Iterable<List<T>> buckets, T[] array) {
         int index = 0;
         for (List<T> bucket : buckets) {
             Collections.sort(bucket);
diff --git a/src/main/java/com/thealgorithms/sorts/PatienceSort.java b/src/main/java/com/thealgorithms/sorts/PatienceSort.java
index 52ed30d586b3..0edce8d9a15d 100644
--- a/src/main/java/com/thealgorithms/sorts/PatienceSort.java
+++ b/src/main/java/com/thealgorithms/sorts/PatienceSort.java
@@ -72,7 +72,7 @@ private static <T extends Comparable<T>> List<List<T>> formPiles(final T[] array
      * @param <T> the type of elements in the piles, must be comparable
      * @return a priority queue containing the top element of each pile
      */
-    private static <T extends Comparable<T>> PriorityQueue<PileNode<T>> mergePiles(final List<List<T>> piles) {
+    private static <T extends Comparable<T>> PriorityQueue<PileNode<T>> mergePiles(final Iterable<List<T>> piles) {
         PriorityQueue<PileNode<T>> pq = new PriorityQueue<>();
         for (List<T> pile : piles) {
             pq.add(new PileNode<>(pile.removeLast(), pile));
diff --git a/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java b/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
index 78d7d81d709f..19f4291d8213 100644
--- a/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java
@@ -78,7 +78,7 @@ private static void populatePigeonHoles(int[] array, List<List<Integer>> pigeonH
      * @param array the array to be sorted
      * @param pigeonHoles the populated pigeonholes
      */
-    private static void collectFromPigeonHoles(int[] array, List<List<Integer>> pigeonHoles) {
+    private static void collectFromPigeonHoles(int[] array, Iterable<List<Integer>> pigeonHoles) {
         int index = 0;
         for (final var pigeonHole : pigeonHoles) {
             for (final int element : pigeonHole) {
diff --git a/src/main/java/com/thealgorithms/sorts/TreeSort.java b/src/main/java/com/thealgorithms/sorts/TreeSort.java
index e060af542f98..6f4e5509489d 100644
--- a/src/main/java/com/thealgorithms/sorts/TreeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TreeSort.java
@@ -51,7 +51,7 @@ private <T extends Comparable<T>> T[] doTreeSortArray(T[] unsortedArray) {
         return unsortedArray;
     }
 
-    private <T extends Comparable<T>> List<T> doTreeSortList(List<T> unsortedList) {
+    private <T extends Comparable<T>> List<T> doTreeSortList(Iterable<T> unsortedList) {
         // create a generic BST tree
         BSTRecursiveGeneric<T> tree = new BSTRecursiveGeneric<T>();
 
diff --git a/src/main/java/com/thealgorithms/strings/WordLadder.java b/src/main/java/com/thealgorithms/strings/WordLadder.java
index 084a682b04a7..665e5ff3220d 100644
--- a/src/main/java/com/thealgorithms/strings/WordLadder.java
+++ b/src/main/java/com/thealgorithms/strings/WordLadder.java
@@ -1,8 +1,8 @@
 package com.thealgorithms.strings;
 
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.LinkedList;
-import java.util.List;
 import java.util.Queue;
 import java.util.Set;
 
@@ -22,7 +22,7 @@ private WordLadder() {
      * @param wordList a list of words that can be used in the transformation sequence
      * @return the number of words in the shortest transformation sequence, or 0 if no such sequence exists
      */
-    public static int ladderLength(String beginWord, String endWord, List<String> wordList) {
+    public static int ladderLength(String beginWord, String endWord, Collection<String> wordList) {
         Set<String> wordSet = new HashSet<>(wordList);
 
         if (!wordSet.contains(endWord)) {
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
index 8cd0b0a6838f..f089169903d6 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java
@@ -183,7 +183,7 @@ void testEdgesRange() {
      * @param result list of edges in the Minimum Spanning Tree
      * @return the total weight of the Minimum Spanning Tree
      */
-    int computeTotalWeight(final List<BoruvkaAlgorithm.Edge> result) {
+    int computeTotalWeight(final Iterable<BoruvkaAlgorithm.Edge> result) {
         int totalWeight = 0;
         for (final var edge : result) {
             totalWeight += edge.weight;
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java
index 4a7232447e50..aa8e6beeb3db 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java
@@ -5,6 +5,7 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
@@ -25,7 +26,7 @@ public class EdmondsBlossomAlgorithmTest {
      * @param matching List of matched pairs returned by the algorithm.
      * @return A sorted 2D array of matching pairs.
      */
-    private int[][] convertMatchingToArray(List<int[]> matching) {
+    private int[][] convertMatchingToArray(Collection<int[]> matching) {
         // Convert the list of pairs into an array
         int[][] result = matching.toArray(new int[0][]);
 
diff --git a/src/test/java/com/thealgorithms/misc/WordBoggleTest.java b/src/test/java/com/thealgorithms/misc/WordBoggleTest.java
index 2c79ec796565..1d4ed7c5e737 100644
--- a/src/test/java/com/thealgorithms/misc/WordBoggleTest.java
+++ b/src/test/java/com/thealgorithms/misc/WordBoggleTest.java
@@ -4,6 +4,7 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.stream.Stream;
 import org.junit.jupiter.api.BeforeEach;
@@ -44,7 +45,7 @@ private static Stream<Arguments> provideTestCases() {
 
     @ParameterizedTest
     @MethodSource("provideSpecialCases")
-    void testBoggleBoardSpecialCases(char[][] specialBoard, String[] words, List<String> expectedWords, String testDescription) {
+    void testBoggleBoardSpecialCases(char[][] specialBoard, String[] words, Collection<String> expectedWords, String testDescription) {
         List<String> result = WordBoggle.boggleBoard(specialBoard, words);
         assertEquals(expectedWords.size(), result.size(), "Test failed for: " + testDescription);
         assertTrue(expectedWords.containsAll(result), "Test failed for: " + testDescription);
diff --git a/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
index d0005dda9097..ea692686afd2 100644
--- a/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java
@@ -3,6 +3,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import com.thealgorithms.devutils.entities.ProcessDetails;
+import java.util.Collection;
 import java.util.List;
 import java.util.stream.Stream;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -17,7 +18,7 @@
 class PreemptivePrioritySchedulingTest {
     @ParameterizedTest
     @MethodSource("provideProcessesAndExpectedSchedules")
-    void testPreemptivePriorityScheduling(List<ProcessDetails> processes, List<String> expectedSchedule) {
+    void testPreemptivePriorityScheduling(Collection<ProcessDetails> processes, List<String> expectedSchedule) {
         PreemptivePriorityScheduling scheduler = new PreemptivePriorityScheduling(processes);
         scheduler.scheduleProcesses();
         assertEquals(expectedSchedule, scheduler.ganttChart);
diff --git a/src/test/java/com/thealgorithms/searches/QuickSelectTest.java b/src/test/java/com/thealgorithms/searches/QuickSelectTest.java
index dd04c85b76ae..cf160b0ff4b5 100644
--- a/src/test/java/com/thealgorithms/searches/QuickSelectTest.java
+++ b/src/test/java/com/thealgorithms/searches/QuickSelectTest.java
@@ -4,6 +4,7 @@
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
@@ -225,7 +226,7 @@ private static List<Character> generateRandomCharacters(int n) {
         return RANDOM.ints(n, ASCII_A, ASCII_Z).mapToObj(i -> (char) i).collect(Collectors.toList());
     }
 
-    private static <T extends Comparable<T>> List<T> getSortedCopyOfList(List<T> list) {
+    private static <T extends Comparable<T>> List<T> getSortedCopyOfList(Collection<T> list) {
         return list.stream().sorted().collect(Collectors.toList());
     }
 }

From 30504c179ebc42d15c7b738435a87a3d8bc4053b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 15 Oct 2024 11:06:22 +0530
Subject: [PATCH 0555/1338] Add `MinStackUsingSingleStack` algorithm (#5759)

---
 DIRECTORY.md                                  |  4 ++
 .../stacks/MinStackUsingSingleStack.java      | 65 ++++++++++++++++++
 .../stacks/MinStackUsingSingleStackTest.java  | 66 +++++++++++++++++++
 3 files changed, 135 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/MinStackUsingSingleStack.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/MinStackUsingSingleStackTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 265d1aeeb893..6073904a745e 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -431,6 +431,7 @@
             * [StrobogrammaticNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/StrobogrammaticNumber.java)
             * [SumOfArithmeticSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SumOfArithmeticSeries.java)
             * [SumOfDigits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SumOfDigits.java)
+            * [SumOfOddNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java)
             * [SumWithoutArithmeticOperators](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SumWithoutArithmeticOperators.java)
             * [TrinomialTriangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java)
             * [TwinPrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/TwinPrime.java)
@@ -612,6 +613,7 @@
             * [InfixToPrefix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java)
             * [LargestRectangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/LargestRectangle.java)
             * [MaximumMinimumWindow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java)
+            * [MinStackUsingSingleStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MinStackUsingSingleStack.java)
             * [NextGreaterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java)
             * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
             * [PostfixEvaluator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java)
@@ -1009,6 +1011,7 @@
             * [StrobogrammaticNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/StrobogrammaticNumberTest.java)
             * [SumOfArithmeticSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SumOfArithmeticSeriesTest.java)
             * [SumOfDigitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SumOfDigitsTest.java)
+            * [SumOfOddNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java)
             * [SumWithoutArithmeticOperatorsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SumWithoutArithmeticOperatorsTest.java)
             * [TestArmstrong](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TestArmstrong.java)
             * [TwinPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TwinPrimeTest.java)
@@ -1164,6 +1167,7 @@
             * [InfixToPostfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java)
             * [InfixToPrefixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java)
             * [LargestRectangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java)
+            * [MinStackUsingSingleStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/MinStackUsingSingleStackTest.java)
             * [NextGreaterElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java)
             * [NextSmallerElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
             * [PostfixEvaluatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java)
diff --git a/src/main/java/com/thealgorithms/stacks/MinStackUsingSingleStack.java b/src/main/java/com/thealgorithms/stacks/MinStackUsingSingleStack.java
new file mode 100644
index 000000000000..f5e526b102cf
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/MinStackUsingSingleStack.java
@@ -0,0 +1,65 @@
+package com.thealgorithms.stacks;
+
+import java.util.EmptyStackException;
+import java.util.Stack;
+
+/**
+ * Min-Stack implementation using a single stack.
+ *
+ * This stack supports push, pop, and retrieving the minimum element
+ * in constant time (O(1)) using a modified approach where the stack
+ * stores both the element and the minimum value so far.
+ *
+ * @author Hardvan
+ */
+public class MinStackUsingSingleStack {
+    private final Stack<long[]> stack = new Stack<>();
+
+    /**
+     * Pushes a new value onto the stack.
+     * Each entry stores both the value and the minimum value so far.
+     *
+     * @param value The value to be pushed onto the stack.
+     */
+    public void push(int value) {
+        if (stack.isEmpty()) {
+            stack.push(new long[] {value, value});
+        } else {
+            long minSoFar = Math.min(value, stack.peek()[1]);
+            stack.push(new long[] {value, minSoFar});
+        }
+    }
+
+    /**
+     * Removes the top element from the stack.
+     */
+    public void pop() {
+        if (!stack.isEmpty()) {
+            stack.pop();
+        }
+    }
+
+    /**
+     * Retrieves the top element from the stack.
+     *
+     * @return The top element of the stack.
+     */
+    public int top() {
+        if (!stack.isEmpty()) {
+            return (int) stack.peek()[0];
+        }
+        throw new EmptyStackException();
+    }
+
+    /**
+     * Retrieves the minimum element in the stack.
+     *
+     * @return The minimum element so far.
+     */
+    public int getMin() {
+        if (!stack.isEmpty()) {
+            return (int) stack.peek()[1];
+        }
+        throw new EmptyStackException();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/MinStackUsingSingleStackTest.java b/src/test/java/com/thealgorithms/stacks/MinStackUsingSingleStackTest.java
new file mode 100644
index 000000000000..90887294638f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/MinStackUsingSingleStackTest.java
@@ -0,0 +1,66 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.EmptyStackException;
+import org.junit.jupiter.api.Test;
+
+public class MinStackUsingSingleStackTest {
+
+    @Test
+    public void testBasicOperations() {
+        MinStackUsingSingleStack minStack = new MinStackUsingSingleStack();
+
+        minStack.push(3);
+        minStack.push(5);
+        assertEquals(3, minStack.getMin(), "Minimum should be 3");
+
+        minStack.push(2);
+        minStack.push(1);
+        assertEquals(1, minStack.getMin(), "Minimum should be 1");
+
+        minStack.pop();
+        assertEquals(2, minStack.getMin(), "Minimum should be 2");
+
+        minStack.pop();
+        assertEquals(3, minStack.getMin(), "Minimum should be 3");
+    }
+
+    @Test
+    public void testTopElement() {
+        MinStackUsingSingleStack minStack = new MinStackUsingSingleStack();
+
+        minStack.push(8);
+        minStack.push(10);
+        assertEquals(10, minStack.top(), "Top element should be 10");
+
+        minStack.pop();
+        assertEquals(8, minStack.top(), "Top element should be 8");
+    }
+
+    @Test
+    public void testGetMinAfterPops() {
+        MinStackUsingSingleStack minStack = new MinStackUsingSingleStack();
+
+        minStack.push(5);
+        minStack.push(3);
+        minStack.push(7);
+
+        assertEquals(3, minStack.getMin(), "Minimum should be 3");
+
+        minStack.pop(); // Popping 7
+        assertEquals(3, minStack.getMin(), "Minimum should still be 3");
+
+        minStack.pop(); // Popping 3
+        assertEquals(5, minStack.getMin(), "Minimum should now be 5");
+    }
+
+    @Test
+    public void testEmptyStack() {
+        MinStackUsingSingleStack minStack = new MinStackUsingSingleStack();
+
+        assertThrows(EmptyStackException.class, minStack::top, "Should throw exception on top()");
+        assertThrows(EmptyStackException.class, minStack::getMin, "Should throw exception on getMin()");
+    }
+}

From 776946e165ce659cbe334f653c4e8f480f36f9fd Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 15 Oct 2024 13:42:50 +0530
Subject: [PATCH 0556/1338] feat: Add `MinStackUsingTwoStacks` new algorithm
 with Junit tests (#5758)

---
 DIRECTORY.md                                  |  2 +
 .../stacks/MinStackUsingTwoStacks.java        | 57 +++++++++++++++++++
 .../stacks/MinStackUsingTwoStacksTest.java    | 38 +++++++++++++
 3 files changed, 97 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/MinStackUsingTwoStacks.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6073904a745e..cb26c292b5e4 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -614,6 +614,7 @@
             * [LargestRectangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/LargestRectangle.java)
             * [MaximumMinimumWindow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java)
             * [MinStackUsingSingleStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MinStackUsingSingleStack.java)
+            * [MinStackUsingTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MinStackUsingTwoStacks.java)
             * [NextGreaterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java)
             * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
             * [PostfixEvaluator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java)
@@ -1168,6 +1169,7 @@
             * [InfixToPrefixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java)
             * [LargestRectangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java)
             * [MinStackUsingSingleStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/MinStackUsingSingleStackTest.java)
+            * [MinStackUsingTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java)
             * [NextGreaterElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java)
             * [NextSmallerElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
             * [PostfixEvaluatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java)
diff --git a/src/main/java/com/thealgorithms/stacks/MinStackUsingTwoStacks.java b/src/main/java/com/thealgorithms/stacks/MinStackUsingTwoStacks.java
new file mode 100644
index 000000000000..47e337c80b59
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/MinStackUsingTwoStacks.java
@@ -0,0 +1,57 @@
+package com.thealgorithms.stacks;
+
+import java.util.Stack;
+
+/**
+ * Min-Stack implementation that supports push, pop, and retrieving the minimum element in constant time.
+ *
+ * @author Hardvan
+ */
+public final class MinStackUsingTwoStacks {
+    MinStackUsingTwoStacks() {
+    }
+
+    private final Stack<Integer> stack = new Stack<>();
+    private final Stack<Integer> minStack = new Stack<>();
+
+    /**
+     * Pushes a new element onto the {@code stack}.
+     * If the value is less than or equal to the current minimum, it is also pushed onto the {@code minStack}.
+     *
+     * @param value The value to be pushed.
+     */
+    public void push(int value) {
+        stack.push(value);
+        if (minStack.isEmpty() || value <= minStack.peek()) {
+            minStack.push(value);
+        }
+    }
+
+    /**
+     * Removes the top element from the stack.
+     * If the element is the minimum element, it is also removed from the {@code minStack}.
+     */
+    public void pop() {
+        if (stack.pop().equals(minStack.peek())) {
+            minStack.pop();
+        }
+    }
+
+    /**
+     * Retrieves the top element of the stack.
+     *
+     * @return The top element.
+     */
+    public int top() {
+        return stack.peek();
+    }
+
+    /**
+     * Retrieves the minimum element in the stack.
+     *
+     * @return The minimum element.
+     */
+    public int getMin() {
+        return minStack.peek();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java b/src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java
new file mode 100644
index 000000000000..e5deb17e9a8f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java
@@ -0,0 +1,38 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class MinStackUsingTwoStacksTest {
+
+    @Test
+    public void testMinStackOperations() {
+        MinStackUsingTwoStacks minStack = new MinStackUsingTwoStacks();
+        minStack.push(3);
+        minStack.push(5);
+        assertEquals(3, minStack.getMin());
+
+        minStack.push(2);
+        minStack.push(1);
+        assertEquals(1, minStack.getMin());
+
+        minStack.pop();
+        assertEquals(2, minStack.getMin());
+    }
+
+    @Test
+    public void testMinStackOperations2() {
+        MinStackUsingTwoStacks minStack = new MinStackUsingTwoStacks();
+        minStack.push(3);
+        minStack.push(5);
+        assertEquals(3, minStack.getMin());
+
+        minStack.push(2);
+        minStack.push(1);
+        assertEquals(1, minStack.getMin());
+
+        minStack.pop();
+        assertEquals(2, minStack.getMin());
+    }
+}

From adf21ab0c87bffd1c774072335a7d9d4f62fcee4 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 15 Oct 2024 14:18:48 +0530
Subject: [PATCH 0557/1338] feat: Add `CelebrityFinder` new algorithm with
 Junit tests (#5756)

---
 DIRECTORY.md                                  |  2 +
 .../thealgorithms/stacks/CelebrityFinder.java | 52 +++++++++++++++++++
 .../stacks/CelebrityFinderTest.java           | 41 +++++++++++++++
 3 files changed, 95 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/CelebrityFinder.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/CelebrityFinderTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index cb26c292b5e4..11ce5b7440a3 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -607,6 +607,7 @@
             * [WiggleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/WiggleSort.java)
           * stacks
             * [BalancedBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java)
+            * [CelebrityFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/CelebrityFinder.java)
             * [DecimalToAnyUsingStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java)
             * [DuplicateBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java)
             * [InfixToPostfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java)
@@ -1163,6 +1164,7 @@
             * [WiggleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java)
           * stacks
             * [BalancedBracketsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/BalancedBracketsTest.java)
+            * [CelebrityFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/CelebrityFinderTest.java)
             * [DecimalToAnyUsingStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/DecimalToAnyUsingStackTest.java)
             * [DuplicateBracketsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java)
             * [InfixToPostfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java)
diff --git a/src/main/java/com/thealgorithms/stacks/CelebrityFinder.java b/src/main/java/com/thealgorithms/stacks/CelebrityFinder.java
new file mode 100644
index 000000000000..67ac861ef82b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/CelebrityFinder.java
@@ -0,0 +1,52 @@
+package com.thealgorithms.stacks;
+
+import java.util.Stack;
+
+/**
+ * Solves the celebrity problem using a stack-based algorithm.
+ *
+ * <p>Celebrity is someone known by everyone but doesn't know anyone else.
+ * <p>Applications: Graph theory and social network analysis.
+ *
+ * @author Hardvan
+ */
+public final class CelebrityFinder {
+    private CelebrityFinder() {
+    }
+
+    /**
+     * Finds the celebrity in the given party matrix using a stack-based algorithm.
+     *
+     * @param party A 2D matrix where party[i][j] is 1 if i knows j, otherwise 0.
+     * @return The index of the celebrity, or -1 if there is no celebrity.
+     */
+    public static int findCelebrity(int[][] party) {
+
+        // Push all people onto the stack
+        Stack<Integer> stack = new Stack<>();
+        for (int i = 0; i < party.length; i++) {
+            stack.push(i);
+        }
+
+        // Find the potential celebrity by comparing pairs
+        while (stack.size() > 1) {
+            int person1 = stack.pop();
+            int person2 = stack.pop();
+
+            if (party[person1][person2] == 1) {
+                stack.push(person2); // person1 knows person2, so person2 might be the celebrity
+            } else {
+                stack.push(person1); // person1 doesn't know person2, so person1 might be the celebrity
+            }
+        }
+
+        // Verify the candidate
+        int candidate = stack.pop();
+        for (int i = 0; i < party.length; i++) {
+            if (i != candidate && (party[candidate][i] == 1 || party[i][candidate] == 0)) {
+                return -1;
+            }
+        }
+        return candidate;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/CelebrityFinderTest.java b/src/test/java/com/thealgorithms/stacks/CelebrityFinderTest.java
new file mode 100644
index 000000000000..da0217940c2c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/CelebrityFinderTest.java
@@ -0,0 +1,41 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class CelebrityFinderTest {
+
+    @ParameterizedTest
+    @MethodSource("providePartyMatrices")
+    public void testCelebrityFinder(int[][] party, int expected) {
+        assertEquals(expected, CelebrityFinder.findCelebrity(party));
+    }
+
+    private static Stream<Arguments> providePartyMatrices() {
+        return Stream.of(
+            // Test case 1: Celebrity exists
+            Arguments.of(new int[][] {{0, 1, 1}, {0, 0, 1}, {0, 0, 0}}, 2),
+
+            // Test case 2: No celebrity
+            Arguments.of(new int[][] {{0, 1, 0}, {1, 0, 1}, {1, 1, 0}}, -1),
+
+            // Test case 3: Everyone knows each other, no celebrity
+            Arguments.of(new int[][] {{0, 1, 1}, {1, 0, 1}, {1, 1, 0}}, -1),
+
+            // Test case 4: Single person, they are trivially a celebrity
+            Arguments.of(new int[][] {{0}}, 0),
+
+            // Test case 5: All know the last person, and they know no one
+            Arguments.of(new int[][] {{0, 1, 1, 1}, {0, 0, 1, 1}, {0, 0, 0, 1}, {0, 0, 0, 0}}, 3),
+
+            // Test case 6: Larger party with no celebrity
+            Arguments.of(new int[][] {{0, 1, 1, 0}, {1, 0, 0, 1}, {0, 1, 0, 1}, {1, 1, 1, 0}}, -1),
+
+            // Test case 7: Celebrity at the start of the matrix
+            Arguments.of(new int[][] {{0, 0, 0}, {1, 0, 1}, {1, 1, 0}}, 0));
+    }
+}

From 32bf532133bc83ae495557ab0e6b3e4c7eab4196 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 15 Oct 2024 14:29:16 +0530
Subject: [PATCH 0558/1338] refactor: Enhance docs, add more tests in
 `ArrayCombination` (#5841)

---
 .../backtracking/ArrayCombination.java        | 28 +++++++++++++------
 .../backtracking/ArrayCombinationTest.java    |  8 ++++--
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
index a064decc0eb7..6569896bd1b7 100644
--- a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
+++ b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
@@ -4,22 +4,24 @@
 import java.util.List;
 
 /**
- * Finds all combinations of 0...n-1 of length k
+ * This class provides methods to find all combinations of integers from 0 to n-1
+ * of a specified length k using backtracking.
  */
 public final class ArrayCombination {
     private ArrayCombination() {
     }
 
     /**
-     * Finds all combinations of length k of 0..n-1 using backtracking.
+     * Generates all possible combinations of length k from the integers 0 to n-1.
      *
-     * @param n Number of the elements.
-     * @param k Length of the combination.
-     * @return A list of all combinations of length k.
+     * @param n The total number of elements (0 to n-1).
+     * @param k The desired length of each combination.
+     * @return A list containing all combinations of length k.
+     * @throws IllegalArgumentException if n or k are negative, or if k is greater than n.
      */
     public static List<List<Integer>> combination(int n, int k) {
         if (n < 0 || k < 0 || k > n) {
-            throw new IllegalArgumentException("Wrong input.");
+            throw new IllegalArgumentException("Invalid input: n must be non-negative, k must be non-negative and less than or equal to n.");
         }
 
         List<List<Integer>> combinations = new ArrayList<>();
@@ -27,9 +29,19 @@ public static List<List<Integer>> combination(int n, int k) {
         return combinations;
     }
 
+    /**
+     * A helper method that uses backtracking to find combinations.
+     *
+     * @param combinations The list to store all valid combinations found.
+     * @param current The current combination being built.
+     * @param start The starting index for the current recursion.
+     * @param n The total number of elements (0 to n-1).
+     * @param k The desired length of each combination.
+     */
     private static void combine(List<List<Integer>> combinations, List<Integer> current, int start, int n, int k) {
-        if (current.size() == k) { // Base case: combination found
-            combinations.add(new ArrayList<>(current)); // Copy to avoid modification
+        // Base case: combination found
+        if (current.size() == k) {
+            combinations.add(new ArrayList<>(current));
             return;
         }
 
diff --git a/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java b/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java
index a4ff7fe892d5..a6a3714cb594 100644
--- a/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java
@@ -27,10 +27,14 @@ void testCombinationThrows(int n, int k) {
 
     private static Stream<Arguments> regularInputs() {
         return Stream.of(Arguments.of(0, 0, List.of(new ArrayList<Integer>())), Arguments.of(1, 0, List.of(new ArrayList<Integer>())), Arguments.of(1, 1, List.of(List.of(0))), Arguments.of(3, 0, List.of(new ArrayList<Integer>())), Arguments.of(3, 1, List.of(List.of(0), List.of(1), List.of(2))),
-            Arguments.of(4, 2, List.of(List.of(0, 1), List.of(0, 2), List.of(0, 3), List.of(1, 2), List.of(1, 3), List.of(2, 3))));
+            Arguments.of(4, 2, List.of(List.of(0, 1), List.of(0, 2), List.of(0, 3), List.of(1, 2), List.of(1, 3), List.of(2, 3))),
+            Arguments.of(5, 3, List.of(List.of(0, 1, 2), List.of(0, 1, 3), List.of(0, 1, 4), List.of(0, 2, 3), List.of(0, 2, 4), List.of(0, 3, 4), List.of(1, 2, 3), List.of(1, 2, 4), List.of(1, 3, 4), List.of(2, 3, 4))),
+            Arguments.of(6, 4,
+                List.of(List.of(0, 1, 2, 3), List.of(0, 1, 2, 4), List.of(0, 1, 2, 5), List.of(0, 1, 3, 4), List.of(0, 1, 3, 5), List.of(0, 1, 4, 5), List.of(0, 2, 3, 4), List.of(0, 2, 3, 5), List.of(0, 2, 4, 5), List.of(0, 3, 4, 5), List.of(1, 2, 3, 4), List.of(1, 2, 3, 5), List.of(1, 2, 4, 5),
+                    List.of(1, 3, 4, 5), List.of(2, 3, 4, 5))));
     }
 
     private static Stream<Arguments> wrongInputs() {
-        return Stream.of(Arguments.of(-1, 0), Arguments.of(0, -1), Arguments.of(2, 100));
+        return Stream.of(Arguments.of(-1, 0), Arguments.of(0, -1), Arguments.of(2, 100), Arguments.of(3, 4));
     }
 }

From be70801aa2fde9d9f183a3ae8d7f787fbc372992 Mon Sep 17 00:00:00 2001
From: Saahil Mahato <115351000+saahil-mahato@users.noreply.github.com>
Date: Tue, 15 Oct 2024 14:57:58 +0545
Subject: [PATCH 0559/1338] feat: add bresenham's line drawing algorithm
 (#5779)

---
 .../thealgorithms/geometry/BresenhamLine.java | 69 +++++++++++++++++++
 .../geometry/BresenhamLineTest.java           | 57 +++++++++++++++
 2 files changed, 126 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/geometry/BresenhamLine.java
 create mode 100644 src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java

diff --git a/src/main/java/com/thealgorithms/geometry/BresenhamLine.java b/src/main/java/com/thealgorithms/geometry/BresenhamLine.java
new file mode 100644
index 000000000000..51d9930c0250
--- /dev/null
+++ b/src/main/java/com/thealgorithms/geometry/BresenhamLine.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.geometry;
+
+import java.awt.Point;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The {@code BresenhamLine} class implements the Bresenham's line algorithm,
+ * which is an efficient way to determine the points of a straight line
+ * between two given points in a 2D space.
+ *
+ * <p>This algorithm uses integer arithmetic to calculate the points,
+ * making it suitable for rasterization in computer graphics.</p>
+ *
+ * For more information, please visit {@link https://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm}
+ */
+public final class BresenhamLine {
+
+    private BresenhamLine() {
+        // Private constructor to prevent instantiation.
+    }
+
+    /**
+     * Finds the list of points that form a straight line between two endpoints.
+     *
+     * @param x0 the x-coordinate of the starting point
+     * @param y0 the y-coordinate of the starting point
+     * @param x1 the x-coordinate of the ending point
+     * @param y1 the y-coordinate of the ending point
+     * @return a {@code List<Point>} containing all points on the line
+     */
+    public static List<Point> findLine(int x0, int y0, int x1, int y1) {
+        List<Point> line = new ArrayList<>();
+
+        // Calculate differences and steps for each axis
+        int dx = Math.abs(x1 - x0); // Change in x
+        int dy = Math.abs(y1 - y0); // Change in y
+        int sx = (x0 < x1) ? 1 : -1; // Step in x direction
+        int sy = (y0 < y1) ? 1 : -1; // Step in y direction
+        int err = dx - dy; // Initial error term
+
+        // Loop until we reach the endpoint
+        while (true) {
+            line.add(new Point(x0, y0)); // Add current point to the line
+
+            // Check if we've reached the endpoint
+            if (x0 == x1 && y0 == y1) {
+                break; // Exit loop if endpoint is reached
+            }
+
+            // Calculate error term doubled for decision making
+            final int e2 = err * 2;
+
+            // Adjust x coordinate if necessary
+            if (e2 > -dy) {
+                err -= dy; // Update error term
+                x0 += sx; // Move to next point in x direction
+            }
+
+            // Adjust y coordinate if necessary
+            if (e2 < dx) {
+                err += dx; // Update error term
+                y0 += sy; // Move to next point in y direction
+            }
+        }
+
+        return line; // Return the list of points forming the line
+    }
+}
diff --git a/src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java b/src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java
new file mode 100644
index 000000000000..9df308497ddf
--- /dev/null
+++ b/src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java
@@ -0,0 +1,57 @@
+package com.thealgorithms.geometry;
+
+import java.awt.Point;
+import java.util.Collection;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+/**
+ * The {@code BresenhamLineTest} class contains unit tests for the
+ * {@code BresenhamLine} class, specifically testing the
+ * {@code findLine} method.
+ *
+ * <p>This class uses parameterized tests to validate the output of
+ * Bresenham's line algorithm for various input points.</p>
+ */
+class BresenhamLineTest {
+
+    /**
+     * Provides test cases for the parameterized test.
+     *
+     * <p>Each test case includes starting coordinates, ending coordinates,
+     * and the expected collection of points that should be generated by the
+     * {@code findLine} method.</p>
+     *
+     * @return a stream of arguments containing test cases
+     */
+    static Stream<Arguments> linePointsProvider() {
+        return Stream.of(Arguments.of(0, 0, 5, 5, List.of(new Point(0, 0), new Point(1, 1), new Point(2, 2), new Point(3, 3), new Point(4, 4), new Point(5, 5))), Arguments.of(0, 0, 5, 0, List.of(new Point(0, 0), new Point(1, 0), new Point(2, 0), new Point(3, 0), new Point(4, 0), new Point(5, 0))),
+            Arguments.of(0, 0, 0, 5, List.of(new Point(0, 0), new Point(0, 1), new Point(0, 2), new Point(0, 3), new Point(0, 4), new Point(0, 5))), Arguments.of(-2, -2, -5, -5, List.of(new Point(-2, -2), new Point(-3, -3), new Point(-4, -4), new Point(-5, -5))),
+            Arguments.of(-1, -1, 2, 2, List.of(new Point(-1, -1), new Point(0, 0), new Point(1, 1), new Point(2, 2))), Arguments.of(2, -1, -1, -4, List.of(new Point(2, -1), new Point(1, -2), new Point(0, -3), new Point(-1, -4))));
+    }
+
+    /**
+     * Tests the {@code findLine} method of the {@code BresenhamLine} class.
+     *
+     * <p>This parameterized test runs multiple times with different sets of
+     * starting and ending coordinates to validate that the generated points
+     * match the expected output.</p>
+     *
+     * @param x0      the x-coordinate of the starting point
+     * @param y0      the y-coordinate of the starting point
+     * @param x1      the x-coordinate of the ending point
+     * @param y1      the y-coordinate of the ending point
+     * @param expected a collection of expected points that should form a line
+     */
+    @ParameterizedTest
+    @MethodSource("linePointsProvider")
+    void testFindLine(int x0, int y0, int x1, int y1, Collection<Point> expected) {
+        List<Point> actual = BresenhamLine.findLine(x0, y0, x1, y1);
+        Assertions.assertEquals(expected.size(), actual.size(), "The size of the points list should match.");
+        Assertions.assertTrue(expected.containsAll(actual) && actual.containsAll(expected), "The points generated should match the expected points.");
+    }
+}

From 9f5478f5995a8d9523bb1dea19c6a191bc2f74d6 Mon Sep 17 00:00:00 2001
From: Radhika Shah <33092356+radhikashah0499@users.noreply.github.com>
Date: Tue, 15 Oct 2024 15:56:10 +0530
Subject: [PATCH 0560/1338] Fix a wrong comment in the tree postorder traversal
 (#5774)

---
 .../java/com/thealgorithms/datastructures/trees/BinaryTree.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java b/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java
index d4d677a4cda0..cf0de4a92030 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java
@@ -281,7 +281,7 @@ public void preOrder(Node localRoot) {
     }
 
     /**
-     * Prints rightChild - leftChild - root
+     * Prints leftChild - rightChild - root
      *
      * @param localRoot The local root of the binary tree
      */

From 640d82358072106285f1ec952b0b671742dfd7bf Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 15 Oct 2024 15:59:37 +0530
Subject: [PATCH 0561/1338] Add tests, remove main in PalindromePrime (#5773)

---
 DIRECTORY.md                                  |  3 ++
 .../thealgorithms/misc/PalindromePrime.java   | 52 ++++++++++--------
 .../misc/PalindromePrimeTest.java             | 53 +++++++++++++++++++
 3 files changed, 85 insertions(+), 23 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 11ce5b7440a3..d0de70715bbc 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -304,6 +304,7 @@
             * [WildcardMatching](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java)
             * [WineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java)
           * geometry
+            * [BresenhamLine](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/BresenhamLine.java)
             * [ConvexHull](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/ConvexHull.java)
             * [GrahamScan](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/GrahamScan.java)
             * [Point](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/Point.java)
@@ -902,6 +903,7 @@
             * [WildcardMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java)
             * [WineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WineProblemTest.java)
           * geometry
+            * [BresenhamLineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java)
             * [ConvexHullTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java)
             * [GrahamScanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
           * greedyalgorithms
@@ -1026,6 +1028,7 @@
             * [MedianOfMatrixtest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java)
             * [MedianOfRunningArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java)
             * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java)
+            * [PalindromePrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java)
             * [PalindromeSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java)
             * [RangeInSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java)
             * [ThreeSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java)
diff --git a/src/main/java/com/thealgorithms/misc/PalindromePrime.java b/src/main/java/com/thealgorithms/misc/PalindromePrime.java
index e1cbf3ff839a..164e957a9d12 100644
--- a/src/main/java/com/thealgorithms/misc/PalindromePrime.java
+++ b/src/main/java/com/thealgorithms/misc/PalindromePrime.java
@@ -1,51 +1,57 @@
 package com.thealgorithms.misc;
 
-import java.util.Scanner;
+import java.util.ArrayList;
+import java.util.List;
 
 public final class PalindromePrime {
     private PalindromePrime() {
     }
 
-    public static void main(String[] args) { // Main function
-        Scanner in = new Scanner(System.in);
-        System.out.println("Enter the quantity of First Palindromic Primes you want");
-        int n = in.nextInt(); // Input of how many first palindromic prime we want
-        functioning(n); // calling function - functioning
-        in.close();
-    }
+    public static boolean prime(int num) {
+        if (num < 2) {
+            return false; // Handle edge case for numbers < 2
+        }
+        if (num == 2) {
+            return true; // 2 is prime
+        }
+        if (num % 2 == 0) {
+            return false; // Even numbers > 2 are not prime
+        }
 
-    public static boolean prime(int num) { // checking if number is prime or not
         for (int divisor = 3; divisor <= Math.sqrt(num); divisor += 2) {
             if (num % divisor == 0) {
-                return false; //  false if not prime
+                return false;
             }
         }
-        return true; // True if prime
+        return true;
     }
 
-    public static int reverse(int n) { //  Returns  the reverse of the number
+    public static int reverse(int n) {
         int reverse = 0;
         while (n != 0) {
-            reverse *= 10;
-            reverse += n % 10;
+            reverse = reverse * 10 + (n % 10);
             n /= 10;
         }
         return reverse;
     }
 
-    public static void functioning(int y) {
-        if (y == 0) {
-            return;
+    public static List<Integer> generatePalindromePrimes(int n) {
+        List<Integer> palindromicPrimes = new ArrayList<>();
+        if (n <= 0) {
+            return palindromicPrimes; // Handle case for 0 or negative input
         }
-        System.out.print(2 + "\n"); // print the first Palindromic Prime
+
+        palindromicPrimes.add(2); // 2 is the first palindromic prime
         int count = 1;
         int num = 3;
-        while (count < y) {
-            if (num == reverse(num) && prime(num)) { // number is prime and it's reverse is same
-                count++; // counts check when to terminate while loop
-                System.out.print(num + "\n"); // print the Palindromic Prime
+
+        while (count < n) {
+            if (num == reverse(num) && prime(num)) {
+                palindromicPrimes.add(num);
+                count++;
             }
-            num += 2; // inrease iterator value by two
+            num += 2; // Skip even numbers
         }
+        return palindromicPrimes;
     }
 }
diff --git a/src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java b/src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java
new file mode 100644
index 000000000000..130cd19b47b1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class PalindromePrimeTest {
+
+    @Test
+    public void testPrimeWithPrimeNumbers() {
+        assertTrue(PalindromePrime.prime(2), "2 should be prime");
+        assertTrue(PalindromePrime.prime(3), "3 should be prime");
+        assertTrue(PalindromePrime.prime(5), "5 should be prime");
+        assertTrue(PalindromePrime.prime(11), "11 should be prime");
+    }
+
+    @Test
+    public void testPrimeWithNonPrimeNumbers() {
+        assertFalse(PalindromePrime.prime(1), "1 is not prime");
+        assertFalse(PalindromePrime.prime(4), "4 is not prime");
+        assertFalse(PalindromePrime.prime(9), "9 is not prime");
+        assertFalse(PalindromePrime.prime(15), "15 is not prime");
+    }
+
+    @Test
+    public void testReverse() {
+        assertEquals(123, PalindromePrime.reverse(321), "Reverse of 321 should be 123");
+        assertEquals(7, PalindromePrime.reverse(7), "Reverse of 7 should be 7");
+        assertEquals(1221, PalindromePrime.reverse(1221), "Reverse of 1221 should be 1221");
+    }
+
+    @Test
+    public void testGeneratePalindromePrimes() {
+        List<Integer> result = PalindromePrime.generatePalindromePrimes(5);
+        List<Integer> expected = List.of(2, 3, 5, 7, 11);
+        assertEquals(expected, result, "The first 5 palindromic primes should be [2, 3, 5, 7, 11]");
+    }
+
+    @Test
+    public void testGeneratePalindromePrimesWithZero() {
+        List<Integer> result = PalindromePrime.generatePalindromePrimes(0);
+        assertTrue(result.isEmpty(), "Generating 0 palindromic primes should return an empty list");
+    }
+
+    @Test
+    public void testGeneratePalindromePrimesWithNegativeInput() {
+        List<Integer> result = PalindromePrime.generatePalindromePrimes(-5);
+        assertTrue(result.isEmpty(), "Generating a negative number of palindromic primes should return an empty list");
+    }
+}

From f1aceea732b1766c0f989f7b6f08ea4fd1ba3ee0 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 15 Oct 2024 17:07:35 +0530
Subject: [PATCH 0562/1338] Enhance class & function documentation in
 `CircularBuffer.java` (#5582)

---
 .../buffers/CircularBuffer.java               |  82 ++++++++-
 .../buffers/CircularBufferTest.java           | 163 ++++++------------
 2 files changed, 129 insertions(+), 116 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java b/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
index 15e9a0956226..b709e16fd1f6 100644
--- a/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
+++ b/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
@@ -2,27 +2,62 @@
 
 import java.util.concurrent.atomic.AtomicInteger;
 
+/**
+ * The {@code CircularBuffer} class implements a generic circular (or ring) buffer.
+ * A circular buffer is a fixed-size data structure that operates in a FIFO (First In, First Out) manner.
+ * The buffer allows you to overwrite old data when the buffer is full and efficiently use limited memory.
+ * When the buffer is full, adding a new item will overwrite the oldest data.
+ *
+ * @param <Item> The type of elements stored in the circular buffer.
+ */
 public class CircularBuffer<Item> {
     private final Item[] buffer;
     private final CircularPointer putPointer;
     private final CircularPointer getPointer;
     private final AtomicInteger size = new AtomicInteger(0);
 
+    /**
+     * Constructor to initialize the circular buffer with a specified size.
+     *
+     * @param size The size of the circular buffer.
+     * @throws IllegalArgumentException if the size is zero or negative.
+     */
     public CircularBuffer(int size) {
+        if (size <= 0) {
+            throw new IllegalArgumentException("Buffer size must be positive");
+        }
         // noinspection unchecked
         this.buffer = (Item[]) new Object[size];
         this.putPointer = new CircularPointer(0, size);
         this.getPointer = new CircularPointer(0, size);
     }
 
+    /**
+     * Checks if the circular buffer is empty.
+     * This method is based on the current size of the buffer.
+     *
+     * @return {@code true} if the buffer is empty, {@code false} otherwise.
+     */
     public boolean isEmpty() {
         return size.get() == 0;
     }
 
+    /**
+     * Checks if the circular buffer is full.
+     * The buffer is considered full when its size equals its capacity.
+     *
+     * @return {@code true} if the buffer is full, {@code false} otherwise.
+     */
     public boolean isFull() {
         return size.get() == buffer.length;
     }
 
+    /**
+     * Retrieves and removes the item at the front of the buffer (FIFO).
+     * This operation will move the {@code getPointer} forward.
+     *
+     * @return The item at the front of the buffer, or {@code null} if the buffer is empty.
+     */
     public Item get() {
         if (isEmpty()) {
             return null;
@@ -33,31 +68,64 @@ public Item get() {
         return item;
     }
 
+    /**
+     * Adds an item to the end of the buffer (FIFO).
+     * If the buffer is full, this operation will overwrite the oldest data.
+     *
+     * @param item The item to be added.
+     * @throws IllegalArgumentException if the item is null.
+     * @return {@code true} if the item was successfully added, {@code false} if the buffer was full and the item overwrote existing data.
+     */
     public boolean put(Item item) {
+        if (item == null) {
+            throw new IllegalArgumentException("Null items are not allowed");
+        }
+
+        boolean wasEmpty = isEmpty();
         if (isFull()) {
-            return false;
+            getPointer.getAndIncrement(); // Move get pointer to discard oldest item
+        } else {
+            size.incrementAndGet();
         }
 
         buffer[putPointer.getAndIncrement()] = item;
-        size.incrementAndGet();
-        return true;
+        return wasEmpty;
     }
 
+    /**
+     * The {@code CircularPointer} class is a helper class used to track the current index (pointer)
+     * in the circular buffer.
+     * The max value represents the capacity of the buffer.
+     * The `CircularPointer` class ensures that the pointer automatically wraps around to 0
+     * when it reaches the maximum index.
+     * This is achieved in the `getAndIncrement` method, where the pointer
+     * is incremented and then taken modulo the maximum value (`max`).
+     * This operation ensures that the pointer always stays within the bounds of the buffer.
+     */
     private static class CircularPointer {
         private int pointer;
         private final int max;
 
+        /**
+         * Constructor to initialize the circular pointer.
+         *
+         * @param pointer The initial position of the pointer.
+         * @param max The maximum size (capacity) of the circular buffer.
+         */
         CircularPointer(int pointer, int max) {
             this.pointer = pointer;
             this.max = max;
         }
 
+        /**
+         * Increments the pointer by 1 and wraps it around to 0 if it reaches the maximum value.
+         * This ensures the pointer always stays within the buffer's bounds.
+         *
+         * @return The current pointer value before incrementing.
+         */
         public int getAndIncrement() {
-            if (pointer == max) {
-                pointer = 0;
-            }
             int tmp = pointer;
-            pointer++;
+            pointer = (pointer + 1) % max;
             return tmp;
         }
     }
diff --git a/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java b/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
index be98fde484fa..b115fc187b1a 100644
--- a/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
@@ -1,143 +1,88 @@
 package com.thealgorithms.datastructures.buffers;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.util.ArrayList;
-import java.util.Comparator;
-import java.util.List;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ThreadLocalRandom;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicIntegerArray;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.RepeatedTest;
 import org.junit.jupiter.api.Test;
 
 class CircularBufferTest {
-    private static final int BUFFER_SIZE = 10;
-    private CircularBuffer<Integer> buffer;
-
-    @BeforeEach
-    void setUp() {
-        buffer = new CircularBuffer<>(BUFFER_SIZE);
-    }
 
     @Test
-    void isEmpty() {
+    void testInitialization() {
+        CircularBuffer<Integer> buffer = new CircularBuffer<>(5);
         assertTrue(buffer.isEmpty());
-        buffer.put(generateInt());
-        assertFalse(buffer.isEmpty());
+        assertEquals(Boolean.FALSE, buffer.isFull());
     }
 
     @Test
-    void isFull() {
-        assertFalse(buffer.isFull());
-        buffer.put(generateInt());
-        assertFalse(buffer.isFull());
+    void testPutAndGet() {
+        CircularBuffer<String> buffer = new CircularBuffer<>(3);
 
-        for (int i = 1; i < BUFFER_SIZE; i++) {
-            buffer.put(generateInt());
-        }
+        assertTrue(buffer.put("A"));
+        assertEquals(Boolean.FALSE, buffer.isEmpty());
+        assertEquals(Boolean.FALSE, buffer.isFull());
+
+        buffer.put("B");
+        buffer.put("C");
         assertTrue(buffer.isFull());
+
+        assertEquals("A", buffer.get());
+        assertEquals("B", buffer.get());
+        assertEquals("C", buffer.get());
+        assertTrue(buffer.isEmpty());
     }
 
     @Test
-    void get() {
-        assertNull(buffer.get());
-        for (int i = 0; i < 100; i++) {
-            buffer.put(i);
-        }
-        for (int i = 0; i < BUFFER_SIZE; i++) {
-            assertEquals(i, buffer.get());
-        }
+    void testOverwrite() {
+        CircularBuffer<Integer> buffer = new CircularBuffer<>(3);
+
+        buffer.put(1);
+        buffer.put(2);
+        buffer.put(3);
+        assertEquals(Boolean.FALSE, buffer.put(4)); // This should overwrite 1
+
+        assertEquals(2, buffer.get());
+        assertEquals(3, buffer.get());
+        assertEquals(4, buffer.get());
         assertNull(buffer.get());
     }
 
     @Test
-    void put() {
-        for (int i = 0; i < BUFFER_SIZE; i++) {
-            assertTrue(buffer.put(generateInt()));
-        }
-        assertFalse(buffer.put(generateInt()));
+    void testEmptyBuffer() {
+        CircularBuffer<Double> buffer = new CircularBuffer<>(2);
+        assertNull(buffer.get());
     }
 
-    @RepeatedTest(1000)
-    void concurrentTest() throws InterruptedException {
-        final int numberOfThreadsForProducers = 3;
-        final int numberOfThreadsForConsumers = 2;
-        final int numberOfItems = 300;
-        final CountDownLatch producerCountDownLatch = new CountDownLatch(numberOfItems);
-        final CountDownLatch consumerCountDownLatch = new CountDownLatch(numberOfItems);
-        final AtomicIntegerArray resultAtomicArray = new AtomicIntegerArray(numberOfItems);
-
-        // We are running 2 ExecutorService simultaneously 1 - producer, 2 - consumer
-        // Run producer threads to populate buffer.
-        ExecutorService putExecutors = Executors.newFixedThreadPool(numberOfThreadsForProducers);
-        putExecutors.execute(() -> {
-            while (producerCountDownLatch.getCount() > 0) {
-                int count = (int) producerCountDownLatch.getCount();
-                boolean put = buffer.put(count);
-                while (!put) {
-                    put = buffer.put(count);
-                }
-                producerCountDownLatch.countDown();
-            }
-        });
-
-        // Run consumer threads to retrieve the data from buffer.
-        ExecutorService getExecutors = Executors.newFixedThreadPool(numberOfThreadsForConsumers);
-        getExecutors.execute(() -> {
-            while (consumerCountDownLatch.getCount() > 0) {
-                int count = (int) consumerCountDownLatch.getCount();
-                Integer item = buffer.get();
-                while (item == null) {
-                    item = buffer.get();
-                }
-                resultAtomicArray.set(count - 1, item);
-                consumerCountDownLatch.countDown();
-            }
-        });
-
-        producerCountDownLatch.await();
-        consumerCountDownLatch.await();
-        putExecutors.shutdown();
-        getExecutors.shutdown();
-        shutDownExecutorSafely(putExecutors);
-        shutDownExecutorSafely(getExecutors);
-
-        List<Integer> resultArray = getSortedListFrom(resultAtomicArray);
-        for (int i = 0; i < numberOfItems; i++) {
-            int expectedItem = i + 1;
-            assertEquals(expectedItem, resultArray.get(i));
-        }
+    @Test
+    void testFullBuffer() {
+        CircularBuffer<Character> buffer = new CircularBuffer<>(2);
+        buffer.put('A');
+        buffer.put('B');
+        assertTrue(buffer.isFull());
+        assertEquals(Boolean.FALSE, buffer.put('C')); // This should overwrite 'A'
+        assertEquals('B', buffer.get());
+        assertEquals('C', buffer.get());
     }
 
-    private int generateInt() {
-        return ThreadLocalRandom.current().nextInt(0, 100);
-    }
+    @Test
+    void testIllegalArguments() {
+        assertThrows(IllegalArgumentException.class, () -> new CircularBuffer<>(0));
+        assertThrows(IllegalArgumentException.class, () -> new CircularBuffer<>(-1));
 
-    private void shutDownExecutorSafely(ExecutorService executorService) {
-        try {
-            if (!executorService.awaitTermination(1_000, TimeUnit.MILLISECONDS)) {
-                executorService.shutdownNow();
-            }
-        } catch (InterruptedException e) {
-            executorService.shutdownNow();
-        }
+        CircularBuffer<String> buffer = new CircularBuffer<>(1);
+        assertThrows(IllegalArgumentException.class, () -> buffer.put(null));
     }
 
-    public List<Integer> getSortedListFrom(AtomicIntegerArray atomicArray) {
-        int length = atomicArray.length();
-        ArrayList<Integer> result = new ArrayList<>(length);
-        for (int i = 0; i < length; i++) {
-            result.add(atomicArray.get(i));
+    @Test
+    void testLargeBuffer() {
+        CircularBuffer<Integer> buffer = new CircularBuffer<>(1000);
+        for (int i = 0; i < 1000; i++) {
+            buffer.put(i);
         }
-        result.sort(Comparator.comparingInt(o -> o));
-        return result;
+        assertTrue(buffer.isFull());
+        buffer.put(1000); // This should overwrite 0
+        assertEquals(1, buffer.get());
     }
 }

From 9eff71bf0512253dc3db02356f51bb48fcc25aab Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 15 Oct 2024 17:11:26 +0530
Subject: [PATCH 0563/1338] Add tests for `ConvolutionFFT` (#5767)

---
 DIRECTORY.md                                  |  1 +
 .../java/com/thealgorithms/maths/FFT.java     |  8 +++
 .../maths/ConvolutionFFTTest.java             | 55 +++++++++++++++++++
 3 files changed, 64 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index d0de70715bbc..8d66f77d1ea9 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -938,6 +938,7 @@
             * [CeilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CeilTest.java)
             * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
             * [CombinationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CombinationsTest.java)
+            * [ConvolutionFFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java)
             * [ConvolutionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ConvolutionTest.java)
             * [CrossCorrelationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java)
             * [DeterminantOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DeterminantOfMatrixTest.java)
diff --git a/src/main/java/com/thealgorithms/maths/FFT.java b/src/main/java/com/thealgorithms/maths/FFT.java
index 47605f010b22..91754bd1a80b 100644
--- a/src/main/java/com/thealgorithms/maths/FFT.java
+++ b/src/main/java/com/thealgorithms/maths/FFT.java
@@ -165,6 +165,14 @@ public Complex divide(double n) {
             temp.img = this.img / n;
             return temp;
         }
+
+        public double real() {
+            return real;
+        }
+
+        public double imaginary() {
+            return img;
+        }
     }
 
     /**
diff --git a/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java b/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java
new file mode 100644
index 000000000000..4d627f939d42
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class ConvolutionFFTTest {
+
+    /**
+     * Helper method to create a complex signal from an array of doubles.
+     */
+    private ArrayList<FFT.Complex> createComplexSignal(double[] values) {
+        ArrayList<FFT.Complex> signal = new ArrayList<>();
+        for (double value : values) {
+            signal.add(new FFT.Complex(value, 0));
+        }
+        return signal;
+    }
+
+    /**
+     * Helper method to compare two complex signals for equality within a small margin of error.
+     */
+    private void assertComplexArrayEquals(List<FFT.Complex> expected, List<FFT.Complex> result, double delta) {
+        assertEquals(expected.size(), result.size(), "Signal lengths are not equal.");
+        for (int i = 0; i < expected.size(); i++) {
+            FFT.Complex expectedValue = expected.get(i);
+            FFT.Complex resultValue = result.get(i);
+            assertEquals(expectedValue.real(), resultValue.real(), delta, "Real part mismatch at index " + i);
+            assertEquals(expectedValue.imaginary(), resultValue.imaginary(), delta, "Imaginary part mismatch at index " + i);
+        }
+    }
+
+    @ParameterizedTest(name = "Test case {index}: {3}")
+    @MethodSource("provideTestCases")
+    public void testConvolutionFFT(double[] a, double[] b, double[] expectedOutput, String testDescription) {
+        ArrayList<FFT.Complex> signalA = createComplexSignal(a);
+        ArrayList<FFT.Complex> signalB = createComplexSignal(b);
+
+        ArrayList<FFT.Complex> expected = createComplexSignal(expectedOutput);
+        ArrayList<FFT.Complex> result = ConvolutionFFT.convolutionFFT(signalA, signalB);
+
+        assertComplexArrayEquals(expected, result, 1e-9); // Allow small margin of error
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new double[] {1, 2, 3}, new double[] {4, 5, 6}, new double[] {4, 13, 28, 27, 18}, "Basic test"), Arguments.of(new double[] {0, 0, 0}, new double[] {1, 2, 3}, new double[] {0, 0, 0, 0, 0}, "Test with zero elements"),
+            Arguments.of(new double[] {1, 2}, new double[] {3, 4, 5}, new double[] {3, 10, 13, 10}, "Test with different sizes"), Arguments.of(new double[] {5}, new double[] {2}, new double[] {10}, "Test with single element"),
+            Arguments.of(new double[] {1, -2, 3}, new double[] {-1, 2, -3}, new double[] {-1, 4, -10, 12, -9}, "Test with negative values"));
+    }
+}

From 7e11e9bb82dbf898447a53bbea5ebe39632d20a2 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 15 Oct 2024 17:31:06 +0530
Subject: [PATCH 0564/1338] Add tests for `EulerMethod` (#5769)

---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/maths/EulerMethodTest.java  | 79 +++++++++++++++++++
 2 files changed, 80 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/maths/EulerMethodTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 8d66f77d1ea9..398f61ec8442 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -945,6 +945,7 @@
             * [DigitalRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DigitalRootTest.java)
             * [DistanceFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java)
             * [DudeneyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java)
+            * [EulerMethodTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/EulerMethodTest.java)
             * [EulersFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/EulersFunctionTest.java)
             * [FactorialRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java)
             * [FactorialTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialTest.java)
diff --git a/src/test/java/com/thealgorithms/maths/EulerMethodTest.java b/src/test/java/com/thealgorithms/maths/EulerMethodTest.java
new file mode 100644
index 000000000000..5ae5ac70b1df
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/EulerMethodTest.java
@@ -0,0 +1,79 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.ArrayList;
+import java.util.function.BiFunction;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class EulerMethodTest {
+
+    private static class EulerFullTestCase {
+        double[] params;
+        BiFunction<Double, Double, Double> equation;
+        int expectedSize;
+        double[] expectedFirstPoint;
+        double[] expectedLastPoint;
+
+        EulerFullTestCase(double[] params, BiFunction<Double, Double, Double> equation, int expectedSize, double[] expectedFirstPoint, double[] expectedLastPoint) {
+            this.params = params;
+            this.equation = equation;
+            this.expectedSize = expectedSize;
+            this.expectedFirstPoint = expectedFirstPoint;
+            this.expectedLastPoint = expectedLastPoint;
+        }
+    }
+
+    @ParameterizedTest
+    @MethodSource("eulerStepTestCases")
+    void testEulerStep(double x, double h, double y, BiFunction<Double, Double, Double> equation, double expected) {
+        double result = EulerMethod.eulerStep(x, h, y, equation);
+        assertEquals(expected, result, 1e-9, "Euler step failed for the given equation.");
+    }
+
+    static Stream<Arguments> eulerStepTestCases() {
+        return Stream.of(Arguments.of(0.0, 0.1, 1.0, (BiFunction<Double, Double, Double>) ((x, y) -> x + y), 1.1));
+    }
+
+    @ParameterizedTest
+    @MethodSource("eulerStepInvalidCases")
+    void testEulerStepInvalidInput(double x, double h, double y, BiFunction<Double, Double, Double> equation, Class<? extends Exception> expectedExceptionClass) {
+        assertThrows(expectedExceptionClass, () -> EulerMethod.eulerStep(x, h, y, equation));
+    }
+
+    static Stream<Arguments> eulerStepInvalidCases() {
+        BiFunction<Double, Double, Double> dummyEquation = (x, y) -> x + y;
+        return Stream.of(Arguments.of(0.0, -0.1, 1.0, dummyEquation, IllegalArgumentException.class), Arguments.of(0.0, 0.0, 1.0, dummyEquation, IllegalArgumentException.class));
+    }
+
+    @ParameterizedTest
+    @MethodSource("eulerFullTestCases")
+    void testEulerFull(EulerFullTestCase testCase) {
+        ArrayList<double[]> result = EulerMethod.eulerFull(testCase.params[0], testCase.params[1], testCase.params[2], testCase.params[3], testCase.equation);
+        assertEquals(testCase.expectedSize, result.size(), "Incorrect number of points in the result.");
+        assertArrayEquals(testCase.expectedFirstPoint, result.get(0), 1e-9, "Incorrect first point.");
+        assertArrayEquals(testCase.expectedLastPoint, result.get(result.size() - 1), 1e-9, "Incorrect last point.");
+    }
+
+    static Stream<Arguments> eulerFullTestCases() {
+        return Stream.of(Arguments.of(new EulerFullTestCase(new double[] {0.0, 1.0, 0.5, 0.0}, (x, y) -> x, 3, new double[] {0.0, 0.0}, new double[] {1.0, 0.25})),
+            Arguments.of(new EulerFullTestCase(new double[] {0.0, 1.0, 0.1, 1.0}, (x, y) -> y, 12, new double[] {0.0, 1.0}, new double[] {1.0999999999999999, 2.8531167061100002})),
+            Arguments.of(new EulerFullTestCase(new double[] {0.0, 0.1, 0.1, 1.0}, (x, y) -> x + y, 2, new double[] {0.0, 1.0}, new double[] {0.1, 1.1})));
+    }
+
+    @ParameterizedTest
+    @MethodSource("eulerFullInvalidCases")
+    void testEulerFullInvalidInput(double xStart, double xEnd, double stepSize, double yInitial, BiFunction<Double, Double, Double> equation, Class<? extends Exception> expectedExceptionClass) {
+        assertThrows(expectedExceptionClass, () -> EulerMethod.eulerFull(xStart, xEnd, stepSize, yInitial, equation));
+    }
+
+    static Stream<Arguments> eulerFullInvalidCases() {
+        BiFunction<Double, Double, Double> dummyEquation = (x, y) -> x + y;
+        return Stream.of(Arguments.of(1.0, 0.0, 0.1, 1.0, dummyEquation, IllegalArgumentException.class), Arguments.of(0.0, 1.0, 0.0, 1.0, dummyEquation, IllegalArgumentException.class), Arguments.of(0.0, 1.0, -0.1, 1.0, dummyEquation, IllegalArgumentException.class));
+    }
+}

From 3e10f8f1d8cbcc7f675ae1b6395b1e2e8b2800a4 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 15 Oct 2024 20:22:48 +0530
Subject: [PATCH 0565/1338] Add tests, remove `main`, fix bug in `Sparsity`
 (#5780)

---
 DIRECTORY.md                                  |  1 +
 .../java/com/thealgorithms/misc/Sparsity.java | 28 ++++-----------
 .../com/thealgorithms/misc/SparsityTest.java  | 36 +++++++++++++++++++
 3 files changed, 43 insertions(+), 22 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/misc/SparsityTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 398f61ec8442..652ecbfd6786 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1033,6 +1033,7 @@
             * [PalindromePrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java)
             * [PalindromeSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java)
             * [RangeInSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java)
+            * [SparsityTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/SparsityTest.java)
             * [ThreeSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java)
             * [TwoSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
             * [WordBoggleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/WordBoggleTest.java)
diff --git a/src/main/java/com/thealgorithms/misc/Sparsity.java b/src/main/java/com/thealgorithms/misc/Sparsity.java
index cae2fbdead94..08e50a121da4 100644
--- a/src/main/java/com/thealgorithms/misc/Sparsity.java
+++ b/src/main/java/com/thealgorithms/misc/Sparsity.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.misc;
 
-import java.util.Scanner;
-
 /*
  *A matrix is sparse if many of its coefficients are zero (In general if 2/3rd of matrix elements
  *are 0, it is considered as sparse). The interest in sparsity arises because its exploitation can
@@ -16,12 +14,17 @@ private Sparsity() {
     }
 
     /*
+     * @param mat the input matrix
      * @return Sparsity of matrix
      *
      * where sparsity = number of zeroes/total elements in matrix
      *
      */
     static double sparsity(double[][] mat) {
+        if (mat == null || mat.length == 0) {
+            throw new IllegalArgumentException("Matrix cannot be null or empty");
+        }
+
         int zero = 0;
         // Traversing the matrix to count number of zeroes
         for (int i = 0; i < mat.length; i++) {
@@ -32,25 +35,6 @@ static double sparsity(double[][] mat) {
             }
         }
         // return sparsity
-        return ((double) zero / (mat.length * mat[1].length));
-    }
-
-    // Driver method
-    public static void main(String[] args) {
-        Scanner in = new Scanner(System.in);
-        System.out.println("Enter number of rows in matrix: ");
-        int n = in.nextInt();
-        System.out.println("Enter number of Columns in matrix: ");
-        int m = in.nextInt();
-
-        System.out.println("Enter Matrix elements: ");
-        double[][] mat = new double[n][m];
-        for (int i = 0; i < n; i++) {
-            for (int j = 0; j < m; j++) {
-                mat[i][j] = in.nextDouble();
-            }
-        }
-        System.out.println("Sparsity of matrix is: " + sparsity(mat));
-        in.close();
+        return ((double) zero / (mat.length * mat[0].length));
     }
 }
diff --git a/src/test/java/com/thealgorithms/misc/SparsityTest.java b/src/test/java/com/thealgorithms/misc/SparsityTest.java
new file mode 100644
index 000000000000..b93e4f44937d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/SparsityTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class SparsityTest {
+
+    private static final double DELTA = 1e-9;
+
+    @ParameterizedTest(name = "Test case {index}: {2}")
+    @MethodSource("provideTestCases")
+    public void testSparsity(double[][] matrix, double expectedSparsity, String description) {
+        assertEquals(expectedSparsity, Sparsity.sparsity(matrix), DELTA, description);
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new double[][] {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}, 1.0, "Matrix with all zero elements"), Arguments.of(new double[][] {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}, 0.0, "Matrix with no zero elements"),
+            Arguments.of(new double[][] {{0, 2, 0}, {4, 0, 6}, {0, 8, 0}}, 5.0 / 9.0, "Matrix with mixed elements"), Arguments.of(new double[][] {{0, 1, 0, 2, 0}}, 3.0 / 5.0, "Single-row matrix"), Arguments.of(new double[][] {{1}, {0}, {0}, {2}}, 2.0 / 4.0, "Single-column matrix"),
+            Arguments.of(new double[][] {{0}}, 1.0, "Matrix with a single zero element"), Arguments.of(new double[][] {{5}}, 0.0, "Matrix with a single non-zero element"));
+    }
+
+    @ParameterizedTest(name = "Test case {index}: {1}")
+    @MethodSource("provideExceptionTestCases")
+    public void testSparsityExceptions(double[][] matrix, String description) {
+        assertThrows(IllegalArgumentException.class, () -> Sparsity.sparsity(matrix), description);
+    }
+
+    private static Stream<Arguments> provideExceptionTestCases() {
+        return Stream.of(Arguments.of(new double[][] {}, "Empty matrix should throw IllegalArgumentException"));
+    }
+}

From b35f98a67aff39afc939ea07b4ad339b5a4a77a6 Mon Sep 17 00:00:00 2001
From: Varnan Rathod <119997446+Krounosity@users.noreply.github.com>
Date: Tue, 15 Oct 2024 20:53:10 +0530
Subject: [PATCH 0566/1338] Add Rail Fence Cipher (#5761)

---
 DIRECTORY.md                                  |   2 +
 .../ciphers/RailFenceCipher.java              | 147 ++++++++++++++++++
 .../thealgorithms/ciphers/RailFenceTest.java  |  62 ++++++++
 3 files changed, 211 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/RailFenceTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 652ecbfd6786..3d215855b859 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -73,6 +73,7 @@
             * [PlayfairCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java)
             * [Polybius](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Polybius.java)
             * [ProductCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ProductCipher.java)
+            * [RailFenceCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java)
             * [RSA](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/RSA.java)
             * [SimpleSubCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/SimpleSubCipher.java)
             * [Vigenere](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Vigenere.java)
@@ -729,6 +730,7 @@
             * [HillCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/HillCipherTest.java)
             * [PlayfairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java)
             * [PolybiusTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
+            * [RailFenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RailFenceTest.java)
             * [RSATest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RSATest.java)
             * [SimpleSubCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/SimpleSubCipherTest.java)
             * [VigenereTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/VigenereTest.java)
diff --git a/src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java b/src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java
new file mode 100644
index 000000000000..f81252980468
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java
@@ -0,0 +1,147 @@
+package com.thealgorithms.ciphers;
+
+import java.util.Arrays;
+
+/**
+ * The rail fence cipher (also called a zigzag cipher) is a classical type of transposition cipher.
+ * It derives its name from the manner in which encryption is performed, in analogy to a fence built with horizontal rails.
+ * https://en.wikipedia.org/wiki/Rail_fence_cipher
+ * @author https://github.com/Krounosity
+ */
+
+public class RailFenceCipher {
+
+    // Encrypts the input string using the rail fence cipher method with the given number of rails.
+    public String encrypt(String str, int rails) {
+
+        // Base case of single rail or rails are more than the number of characters in the string
+        if (rails == 1 || rails >= str.length()) {
+            return str;
+        }
+
+        // Boolean flag to determine if the movement is downward or upward in the rail matrix.
+        boolean down = true;
+        // Create a 2D array to represent the rails (rows) and the length of the string (columns).
+        char[][] strRail = new char[rails][str.length()];
+
+        // Initialize all positions in the rail matrix with a placeholder character ('\n').
+        for (int i = 0; i < rails; i++) {
+            Arrays.fill(strRail[i], '\n');
+        }
+
+        int row = 0; // Start at the first row
+        int col = 0; // Start at the first column
+
+        int i = 0;
+
+        // Fill the rail matrix with characters from the string based on the rail pattern.
+        while (col < str.length()) {
+            // Change direction to down when at the first row.
+            if (row == 0) {
+                down = true;
+            }
+            // Change direction to up when at the last row.
+            else if (row == rails - 1) {
+                down = false;
+            }
+
+            // Place the character in the current position of the rail matrix.
+            strRail[row][col] = str.charAt(i);
+            col++; // Move to the next column.
+            // Move to the next row based on the direction.
+            if (down) {
+                row++;
+            } else {
+                row--;
+            }
+
+            i++;
+        }
+
+        // Construct the encrypted string by reading characters row by row.
+        StringBuilder encryptedString = new StringBuilder();
+        for (char[] chRow : strRail) {
+            for (char ch : chRow) {
+                if (ch != '\n') {
+                    encryptedString.append(ch);
+                }
+            }
+        }
+        return encryptedString.toString();
+    }
+    // Decrypts the input string using the rail fence cipher method with the given number of rails.
+    public String decrypt(String str, int rails) {
+
+        // Base case of single rail or rails are more than the number of characters in the string
+        if (rails == 1 || rails >= str.length()) {
+            return str;
+        }
+        // Boolean flag to determine if the movement is downward or upward in the rail matrix.
+        boolean down = true;
+
+        // Create a 2D array to represent the rails (rows) and the length of the string (columns).
+        char[][] strRail = new char[rails][str.length()];
+
+        int row = 0; // Start at the first row
+        int col = 0; // Start at the first column
+
+        // Mark the pattern on the rail matrix using '*'.
+        while (col < str.length()) {
+            // Change direction to down when at the first row.
+            if (row == 0) {
+                down = true;
+            }
+            // Change direction to up when at the last row.
+            else if (row == rails - 1) {
+                down = false;
+            }
+
+            // Mark the current position in the rail matrix.
+            strRail[row][col] = '*';
+            col++; // Move to the next column.
+            // Move to the next row based on the direction.
+            if (down) {
+                row++;
+            } else {
+                row--;
+            }
+        }
+
+        int index = 0; // Index to track characters from the input string.
+        // Fill the rail matrix with characters from the input string based on the marked pattern.
+        for (int i = 0; i < rails; i++) {
+            for (int j = 0; j < str.length(); j++) {
+                if (strRail[i][j] == '*') {
+                    strRail[i][j] = str.charAt(index++);
+                }
+            }
+        }
+
+        // Construct the decrypted string by following the zigzag pattern.
+        StringBuilder decryptedString = new StringBuilder();
+        row = 0; // Reset to the first row
+        col = 0; // Reset to the first column
+
+        while (col < str.length()) {
+            // Change direction to down when at the first row.
+            if (row == 0) {
+                down = true;
+            }
+            // Change direction to up when at the last row.
+            else if (row == rails - 1) {
+                down = false;
+            }
+            // Append the character from the rail matrix to the decrypted string.
+            decryptedString.append(strRail[row][col]);
+            col++; // Move to the next column.
+            // Move to the next row based on the direction.
+            if (down) {
+                row++;
+            } else {
+                row--;
+            }
+        }
+
+        return decryptedString.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/RailFenceTest.java b/src/test/java/com/thealgorithms/ciphers/RailFenceTest.java
new file mode 100644
index 000000000000..2bfa704e3d0b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/RailFenceTest.java
@@ -0,0 +1,62 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class RailFenceTest {
+
+    @Test
+    void testEncryption() {
+        RailFenceCipher cipher = new RailFenceCipher();
+
+        String input = "We are discovered! Flee at once";
+        int rails = 3;
+        String encrypted = cipher.encrypt(input, rails);
+        assertEquals("Wrivdlaneaedsoee!Fe toc  cr e e", encrypted);
+
+        String singleChar = "A";
+        int singleRail = 2;
+        String encryptedSingleChar = cipher.encrypt(singleChar, singleRail);
+        assertEquals("A", encryptedSingleChar);
+
+        String shortString = "Hello";
+        int moreRails = 10;
+        String encryptedShortString = cipher.encrypt(shortString, moreRails);
+        assertEquals("Hello", encryptedShortString);
+
+        String inputSingleRail = "Single line";
+        int singleRailOnly = 1;
+        String encryptedSingleRail = cipher.encrypt(inputSingleRail, singleRailOnly);
+        assertEquals("Single line", encryptedSingleRail);
+    }
+
+    @Test
+    void testDecryption() {
+        RailFenceCipher cipher = new RailFenceCipher();
+
+        // Scenario 1: Basic decryption with multiple rails
+        String encryptedInput = "Wrivdlaneaedsoee!Fe toc  cr e e";
+        int rails = 3;
+        String decrypted = cipher.decrypt(encryptedInput, rails);
+        assertEquals("We are discovered! Flee at once", decrypted);
+
+        // Scenario 2: Single character string decryption
+        String encryptedSingleChar = "A";
+        int singleRail = 2; // More than 1 rail
+        String decryptedSingleChar = cipher.decrypt(encryptedSingleChar, singleRail);
+        assertEquals("A", decryptedSingleChar);
+
+        // Scenario 3: String length less than the number of rails
+        String encryptedShortString = "Hello";
+        int moreRails = 10; // More rails than characters
+        String decryptedShortString = cipher.decrypt(encryptedShortString, moreRails);
+        assertEquals("Hello", decryptedShortString);
+
+        // Scenario 4: Single rail decryption (output should be the same as input)
+        String encryptedSingleRail = "Single line";
+        int singleRailOnly = 1;
+        String decryptedSingleRail = cipher.decrypt(encryptedSingleRail, singleRailOnly);
+        assertEquals("Single line", decryptedSingleRail);
+    }
+}

From 2a518e3c9a44c4333c5ec9283895132264773afb Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 15 Oct 2024 21:25:27 +0530
Subject: [PATCH 0567/1338] Add `Abbreviation` algorithm (#5790)

---
 DIRECTORY.md                                  |  2 +
 .../dynamicprogramming/Abbreviation.java      | 56 +++++++++++++++++++
 .../dynamicprogramming/AbbreviationTest.java  | 44 +++++++++++++++
 3 files changed, 102 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/Abbreviation.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/AbbreviationTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 3d215855b859..6429757179e9 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -261,6 +261,7 @@
             * [StrassenMatrixMultiplication](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplication.java)
             * [TilingProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/TilingProblem.java)
           * dynamicprogramming
+            * [Abbreviation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Abbreviation.java)
             * [BoardPath](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java)
             * [BoundaryFill](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java)
             * [BruteForceKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java)
@@ -862,6 +863,7 @@
             * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
             * [TilingProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/TilingProblemTest.java)
           * dynamicprogramming
+            * [AbbreviationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/AbbreviationTest.java)
             * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
             * [BoundaryFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java)
             * [BruteForceKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Abbreviation.java b/src/main/java/com/thealgorithms/dynamicprogramming/Abbreviation.java
new file mode 100644
index 000000000000..60c0fd0a3cde
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Abbreviation.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.dynamicprogramming;
+
+/**
+ * A class that provides a solution to the abbreviation problem.
+ *
+ * Problem: Given two strings, `a` and `b`, determine if string `a` can be
+ * transformed into string `b` by performing the following operations:
+ * 1. Capitalize zero or more of `a`'s lowercase letters (i.e., convert them to uppercase).
+ * 2. Delete any of the remaining lowercase letters from `a`.
+ *
+ * The task is to determine whether it is possible to make string `a` equal to string `b`.
+ *
+ * @author Hardvan
+ */
+public final class Abbreviation {
+    private Abbreviation() {
+    }
+
+    /**
+     * Determines if string `a` can be transformed into string `b` by capitalizing
+     * some of its lowercase letters and deleting the rest.
+     *
+     * @param a The input string which may contain both uppercase and lowercase letters.
+     * @param b The target string containing only uppercase letters.
+     * @return {@code true} if string `a` can be transformed into string `b`,
+     *         {@code false} otherwise.
+     *
+     * Time Complexity: O(n * m) where n = length of string `a` and m = length of string `b`.
+     * Space Complexity: O(n * m) due to the dynamic programming table.
+     */
+    public static boolean abbr(String a, String b) {
+        int n = a.length();
+        int m = b.length();
+
+        boolean[][] dp = new boolean[n + 1][m + 1];
+
+        dp[0][0] = true;
+
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j <= m; j++) {
+                if (dp[i][j]) {
+                    // Case 1: If the current characters match (or can be capitalized to match)
+                    if (j < m && Character.toUpperCase(a.charAt(i)) == b.charAt(j)) {
+                        dp[i + 1][j + 1] = true;
+                    }
+                    // Case 2: If the character in `a` is lowercase, we can skip it
+                    if (Character.isLowerCase(a.charAt(i))) {
+                        dp[i + 1][j] = true;
+                    }
+                }
+            }
+        }
+
+        return dp[n][m];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/AbbreviationTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/AbbreviationTest.java
new file mode 100644
index 000000000000..4e36edbd7774
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/AbbreviationTest.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class AbbreviationTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testAbbreviation(String a, String b, boolean expected) {
+        assertEquals(expected, Abbreviation.abbr(a, b));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            // Example test case from problem description
+            Arguments.of("daBcd", "ABC", Boolean.TRUE),
+
+            // Test case where transformation is impossible
+            Arguments.of("dBcd", "ABC", Boolean.FALSE),
+
+            // Test case with exact match (all uppercase)
+            Arguments.of("ABC", "ABC", Boolean.TRUE),
+
+            // Test case where input string contains all required letters plus extra lowercase letters
+            Arguments.of("aAbBcC", "ABC", Boolean.TRUE),
+
+            // Test case with only lowercase letters in input
+            Arguments.of("abcd", "ABCD", Boolean.TRUE),
+
+            // Test case with an empty second string (b)
+            Arguments.of("abc", "", Boolean.TRUE),
+
+            // Test case with an empty first string (a) but non-empty second string (b)
+            Arguments.of("", "A", Boolean.FALSE),
+
+            // Complex case with interleaved letters
+            Arguments.of("daBcAbCd", "ABCD", Boolean.FALSE));
+    }
+}

From a53765404923eeba40867cf32fc34709e9ab2d4a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 16 Oct 2024 14:00:27 +0530
Subject: [PATCH 0568/1338] Add `StockProfitCalculator` (#5793)

---
 DIRECTORY.md                                  |  2 ++
 .../StockProfitCalculator.java                | 34 +++++++++++++++++++
 .../StockProfitCalculatorTest.java            | 21 ++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6429757179e9..aa34bf1a9532 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -320,6 +320,7 @@
             * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
             * [MergeIntervals](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java)
             * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java)
+            * [StockProfitCalculator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java)
           * io
             * [BufferedReader](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/io/BufferedReader.java)
           * lineclipping
@@ -920,6 +921,7 @@
             * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
             * [MergeIntervalsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java)
             * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java)
+            * [StockProfitCalculatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java)
           * io
             * [BufferedReaderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/io/BufferedReaderTest.java)
           * lineclipping
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java b/src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java
new file mode 100644
index 000000000000..01950d902b4f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.greedyalgorithms;
+
+/**
+ * The StockProfitCalculator class provides a method to calculate the maximum profit
+ * that can be made from a single buy and sell of one share of stock.
+ * The approach uses a greedy algorithm to efficiently determine the maximum profit.
+ *
+ * @author Hardvan
+ */
+public final class StockProfitCalculator {
+    private StockProfitCalculator() {
+    }
+
+    /**
+     * Calculates the maximum profit from a list of stock prices.
+     *
+     * @param prices an array of integers representing the stock prices on different days
+     * @return the maximum profit that can be achieved from a single buy and sell
+     * transaction, or 0 if no profit can be made
+     */
+    public static int maxProfit(int[] prices) {
+        if (prices == null || prices.length == 0) {
+            return 0;
+        }
+
+        int minPrice = prices[0];
+        int maxProfit = 0;
+        for (int price : prices) {
+            minPrice = Math.min(price, minPrice);
+            maxProfit = Math.max(price - minPrice, maxProfit);
+        }
+        return maxProfit;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java
new file mode 100644
index 000000000000..afad76a34521
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class StockProfitCalculatorTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testMaxProfit(int[] prices, int expected) {
+        assertEquals(expected, StockProfitCalculator.maxProfit(prices));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new int[] {7, 1, 5, 3, 6, 4}, 5), Arguments.of(new int[] {7, 6, 4, 3, 1}, 0), Arguments.of(new int[] {5, 5, 5, 5, 5}, 0), Arguments.of(new int[] {10}, 0), Arguments.of(new int[] {1, 5}, 4), Arguments.of(new int[] {2, 4, 1, 3, 7, 5}, 6));
+    }
+}

From dfff8d95d2fb9a86235a641b8b2fdbbb95196076 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 16 Oct 2024 15:22:17 +0530
Subject: [PATCH 0569/1338] Add `MinimumWaitingTime` algorithm (#5794)

---
 DIRECTORY.md                                  |  2 +
 .../greedyalgorithms/MinimumWaitingTime.java  | 37 +++++++++++++++++++
 .../MinimumWaitingTimeTest.java               | 21 +++++++++++
 3 files changed, 60 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTime.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTimeTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index aa34bf1a9532..e7a08a12abac 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -320,6 +320,7 @@
             * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
             * [MergeIntervals](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java)
             * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java)
+            * [MinimumWaitingTime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTime.java)
             * [StockProfitCalculator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java)
           * io
             * [BufferedReader](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/io/BufferedReader.java)
@@ -921,6 +922,7 @@
             * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
             * [MergeIntervalsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java)
             * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java)
+            * [MinimumWaitingTimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTimeTest.java)
             * [StockProfitCalculatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java)
           * io
             * [BufferedReaderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/io/BufferedReaderTest.java)
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTime.java b/src/main/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTime.java
new file mode 100644
index 000000000000..2341bcdee9f7
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTime.java
@@ -0,0 +1,37 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.Arrays;
+
+/**
+ * The MinimumWaitingTime class provides a method to calculate the minimum
+ * waiting time for a list of queries using a greedy algorithm.
+ *
+ * @author Hardvan
+ */
+public final class MinimumWaitingTime {
+    private MinimumWaitingTime() {
+    }
+
+    /**
+     * Calculates the minimum waiting time for a list of queries.
+     * The function sorts the queries in non-decreasing order and then calculates
+     * the waiting time for each query based on its position in the sorted list.
+     *
+     * @param queries an array of integers representing the query times in picoseconds
+     * @return the minimum waiting time in picoseconds
+     */
+    public static int minimumWaitingTime(int[] queries) {
+        int n = queries.length;
+        if (n <= 1) {
+            return 0;
+        }
+
+        Arrays.sort(queries);
+
+        int totalWaitingTime = 0;
+        for (int i = 0; i < n; i++) {
+            totalWaitingTime += queries[i] * (n - i - 1);
+        }
+        return totalWaitingTime;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTimeTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTimeTest.java
new file mode 100644
index 000000000000..64cb4b80f182
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTimeTest.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class MinimumWaitingTimeTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testMinimumWaitingTime(int[] queries, int expected) {
+        assertEquals(expected, MinimumWaitingTime.minimumWaitingTime(queries));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new int[] {3, 2, 1, 2, 6}, 17), Arguments.of(new int[] {3, 2, 1}, 4), Arguments.of(new int[] {1, 2, 3, 4}, 10), Arguments.of(new int[] {5, 5, 5, 5}, 30), Arguments.of(new int[] {}, 0));
+    }
+}

From 169a01e0c803cc5ccfb739a85c70ee46ea228337 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 16 Oct 2024 16:59:15 +0530
Subject: [PATCH 0570/1338] Enhance documentation in `FractionalKnapsack`
 (#5795)

---
 .../greedyalgorithms/FractionalKnapsack.java  | 41 ++++++++++++-------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java b/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
index 082bd9c68b32..9535a7c6190e 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java
@@ -3,39 +3,50 @@
 import java.util.Arrays;
 import java.util.Comparator;
 
-// Problem Link: https://en.wikipedia.org/wiki/Continuous_knapsack_problem
-
+/**
+ * The FractionalKnapsack class provides a method to solve the fractional knapsack problem
+ * using a greedy algorithm approach. It allows for selecting fractions of items to maximize
+ * the total value in a knapsack with a given weight capacity.
+ *
+ * The problem consists of a set of items, each with a weight and a value, and a knapsack
+ * that can carry a maximum weight. The goal is to maximize the value of items in the knapsack,
+ * allowing for the inclusion of fractions of items.
+ *
+ * Problem Link: https://en.wikipedia.org/wiki/Continuous_knapsack_problem
+ */
 public final class FractionalKnapsack {
     private FractionalKnapsack() {
     }
-    // Function to perform fractional knapsack
+
+    /**
+     * Computes the maximum value that can be accommodated in a knapsack of a given capacity.
+     *
+     * @param weight an array of integers representing the weights of the items
+     * @param value an array of integers representing the values of the items
+     * @param capacity an integer representing the maximum weight capacity of the knapsack
+     * @return the maximum value that can be obtained by including the items in the knapsack
+     */
     public static int fractionalKnapsack(int[] weight, int[] value, int capacity) {
-        // Create a 2D array to store item indices and their value-to-weight ratios.
         double[][] ratio = new double[weight.length][2];
 
-        // Populate the ratio array with item indices and their value-to-weight ratios.
         for (int i = 0; i < weight.length; i++) {
-            ratio[i][0] = i; // Assign item index.
-            ratio[i][1] = value[i] / (double) weight[i]; // Calculate and assign value-to-weight ratio.
+            ratio[i][0] = i;
+            ratio[i][1] = value[i] / (double) weight[i];
         }
 
-        // Sort items by their value-to-weight ratios in descending order.
         Arrays.sort(ratio, Comparator.comparingDouble(o -> o[1]));
 
-        int finalValue = 0; // Variable to store the final knapsack value.
-        double current = capacity; // Variable to track the remaining capacity of the knapsack.
+        int finalValue = 0;
+        double current = capacity;
 
-        // Iterate through the sorted items to select items for the knapsack.
         for (int i = ratio.length - 1; i >= 0; i--) {
-            int index = (int) ratio[i][0]; // Get the item index.
+            int index = (int) ratio[i][0];
             if (current >= weight[index]) {
-                // If the entire item can fit in the knapsack, add its value.
                 finalValue += value[index];
                 current -= weight[index];
             } else {
-                // If only a fraction of the item can fit, add a proportionate value.
                 finalValue += (int) (ratio[i][1] * current);
-                break; // Stop adding items to the knapsack since it's full.
+                break;
             }
         }
         return finalValue;

From 33dee073d08baedae02e6da5d9b672ba3c11813a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 16 Oct 2024 17:46:32 +0530
Subject: [PATCH 0571/1338] Add `AssignmentUsingBitmask` algorithm (#5792)

---
 DIRECTORY.md                                  |  2 +
 .../AssignmentUsingBitmask.java               | 91 +++++++++++++++++++
 .../AssignmentUsingBitmaskTest.java           | 54 +++++++++++
 3 files changed, 147 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmask.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index e7a08a12abac..e511ab40b329 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -262,6 +262,7 @@
             * [TilingProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/TilingProblem.java)
           * dynamicprogramming
             * [Abbreviation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Abbreviation.java)
+            * [AssignmentUsingBitmask](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmask.java)
             * [BoardPath](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java)
             * [BoundaryFill](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java)
             * [BruteForceKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java)
@@ -866,6 +867,7 @@
             * [TilingProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/TilingProblemTest.java)
           * dynamicprogramming
             * [AbbreviationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/AbbreviationTest.java)
+            * [AssignmentUsingBitmaskTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java)
             * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
             * [BoundaryFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java)
             * [BruteForceKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmask.java b/src/main/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmask.java
new file mode 100644
index 000000000000..5a894ca004b7
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmask.java
@@ -0,0 +1,91 @@
+package com.thealgorithms.dynamicprogramming;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * The AssignmentUsingBitmask class is used to calculate the total number of ways
+ * tasks can be distributed among people, given specific constraints on who can perform which tasks.
+ * The approach uses bitmasking and dynamic programming to efficiently solve the problem.
+ *
+ * @author Hardvan
+ */
+public final class AssignmentUsingBitmask {
+
+    private final int totalTasks;
+    private final int[][] dp;
+    private final List<List<Integer>> task;
+    private final int finalMask;
+
+    /**
+     * Constructor for the AssignmentUsingBitmask class.
+     *
+     * @param taskPerformed a list of lists, where each inner list contains the tasks that a person can perform.
+     * @param total        the total number of tasks.
+     */
+    public AssignmentUsingBitmask(List<List<Integer>> taskPerformed, int total) {
+        this.totalTasks = total;
+        this.dp = new int[1 << taskPerformed.size()][total + 1];
+        for (int[] row : dp) {
+            Arrays.fill(row, -1);
+        }
+
+        this.task = new ArrayList<>(totalTasks + 1);
+        for (int i = 0; i <= totalTasks; i++) {
+            this.task.add(new ArrayList<>());
+        }
+
+        // Final mask to check if all persons are included
+        this.finalMask = (1 << taskPerformed.size()) - 1;
+
+        // Fill the task list
+        for (int i = 0; i < taskPerformed.size(); i++) {
+            for (int j : taskPerformed.get(i)) {
+                this.task.get(j).add(i);
+            }
+        }
+    }
+
+    /**
+     * Counts the ways to assign tasks until the given task number with the specified mask.
+     *
+     * @param mask     the bitmask representing the current state of assignments.
+     * @param taskNo   the current task number being processed.
+     * @return the number of ways to assign tasks.
+     */
+    private int countWaysUntil(int mask, int taskNo) {
+        if (mask == finalMask) {
+            return 1;
+        }
+        if (taskNo > totalTasks) {
+            return 0;
+        }
+        if (dp[mask][taskNo] != -1) {
+            return dp[mask][taskNo];
+        }
+
+        int totalWays = countWaysUntil(mask, taskNo + 1);
+
+        // Assign tasks to all possible persons
+        for (int p : task.get(taskNo)) {
+            // If the person is already assigned a task
+            if ((mask & (1 << p)) != 0) {
+                continue;
+            }
+            totalWays += countWaysUntil(mask | (1 << p), taskNo + 1);
+        }
+
+        dp[mask][taskNo] = totalWays;
+        return dp[mask][taskNo];
+    }
+
+    /**
+     * Counts the total number of ways to distribute tasks among persons.
+     *
+     * @return the total number of ways to distribute tasks.
+     */
+    public int countNoOfWays() {
+        return countWaysUntil(0, 1);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java
new file mode 100644
index 000000000000..0258f3950510
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public final class AssignmentUsingBitmaskTest {
+
+    @Test
+    public void testCountNoOfWays() {
+        int totalTasks = 5;
+
+        List<List<Integer>> taskPerformed = Arrays.asList(Arrays.asList(1, 3, 4), Arrays.asList(1, 2, 5), Arrays.asList(3, 4));
+
+        AssignmentUsingBitmask assignment = new AssignmentUsingBitmask(taskPerformed, totalTasks);
+        int ways = assignment.countNoOfWays();
+        assertEquals(10, ways);
+    }
+
+    @Test
+    public void testNoPossibleAssignments() {
+        int totalTasks = 3;
+
+        List<List<Integer>> taskPerformed = Arrays.asList(Arrays.asList(2), Arrays.asList(3));
+
+        AssignmentUsingBitmask assignment = new AssignmentUsingBitmask(taskPerformed, totalTasks);
+        int ways = assignment.countNoOfWays();
+        assertEquals(1, ways);
+    }
+
+    @Test
+    public void testSinglePersonMultipleTasks() {
+        int totalTasks = 3;
+
+        List<List<Integer>> taskPerformed = Arrays.asList(Arrays.asList(1, 2, 3));
+
+        AssignmentUsingBitmask assignment = new AssignmentUsingBitmask(taskPerformed, totalTasks);
+        int ways = assignment.countNoOfWays();
+        assertEquals(3, ways);
+    }
+
+    @Test
+    public void testMultiplePeopleSingleTask() {
+        int totalTasks = 1;
+
+        List<List<Integer>> taskPerformed = Arrays.asList(Arrays.asList(1), Arrays.asList(1));
+
+        AssignmentUsingBitmask assignment = new AssignmentUsingBitmask(taskPerformed, totalTasks);
+        int ways = assignment.countNoOfWays();
+        assertEquals(0, ways);
+    }
+}

From e499d3b63e9cb3dc711ddd5d4a2fc3faba9b3d46 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 19 Oct 2024 12:27:26 +0000
Subject: [PATCH 0572/1338] Bump org.mockito:mockito-core from 5.14.1 to 5.14.2
 (#5856)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.14.1 to 5.14.2.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.14.1...v5.14.2)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 812f46c700ea..19357d7c8b15 100644
--- a/pom.xml
+++ b/pom.xml
@@ -43,7 +43,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.14.1</version>
+            <version>5.14.2</version>
             <scope>test</scope>
         </dependency>
 

From 7f21f2d316b5a7df485df69a76fba69f15b1dc23 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 22 Oct 2024 11:07:55 +0300
Subject: [PATCH 0573/1338] Bump org.junit:junit-bom from 5.11.2 to 5.11.3
 (#5934)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.11.2 to 5.11.3.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.2...r5.11.3)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 19357d7c8b15..45354fc781f4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.11.2</version>
+                <version>5.11.3</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From cff79d443952a486b4b7cd70916878adfe70a26a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 22 Oct 2024 11:11:41 +0300
Subject: [PATCH 0574/1338] Bump org.junit.jupiter:junit-jupiter from 5.11.2 to
 5.11.3 (#5935)

Bumps [org.junit.jupiter:junit-jupiter](https://github.com/junit-team/junit5) from 5.11.2 to 5.11.3.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.2...r5.11.3)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 45354fc781f4..2d6512fd1574 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.11.2</version>
+            <version>5.11.3</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From ae37b5f152b52b294cc4fbd83cd30d045afaaef5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 22 Oct 2024 11:35:26 +0300
Subject: [PATCH 0575/1338] Bump com.github.spotbugs:spotbugs-maven-plugin from
 4.8.6.4 to 4.8.6.5 (#5936)

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.8.6.4 to 4.8.6.5.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.8.6.4...spotbugs-maven-plugin-4.8.6.5)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 2d6512fd1574..1b70c0a83f1b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -132,7 +132,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.8.6.4</version>
+                <version>4.8.6.5</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From c440c1d69e65f7188b2080e350dc9a53c624c523 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 22 Oct 2024 11:39:55 +0300
Subject: [PATCH 0576/1338] Bump org.junit.jupiter:junit-jupiter-api from
 5.11.2 to 5.11.3 (#5937)

Bumps [org.junit.jupiter:junit-jupiter-api](https://github.com/junit-team/junit5) from 5.11.2 to 5.11.3.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.2...r5.11.3)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter-api
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 1b70c0a83f1b..ec42ffc3c86d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -51,7 +51,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>5.11.2</version>
+            <version>5.11.3</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 69a142441542378083afeb974dbd46fd66ff2ec7 Mon Sep 17 00:00:00 2001
From: ANANT JAIN <139585700+anant-jain01@users.noreply.github.com>
Date: Tue, 22 Oct 2024 23:02:51 +0530
Subject: [PATCH 0577/1338] Add StalinSort (#5738)

---
 .../sorts/AdaptiveMergeSort.java              | 40 ++++++++++++++
 .../com/thealgorithms/sorts/StalinSort.java   | 21 ++++++++
 .../sorts/AdaptiveMergeSortTest.java          | 53 +++++++++++++++++++
 .../thealgorithms/sorts/StalinSortTest.java   | 53 +++++++++++++++++++
 4 files changed, 167 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java
 create mode 100644 src/main/java/com/thealgorithms/sorts/StalinSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/StalinSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java b/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java
new file mode 100644
index 000000000000..2c71bae8b557
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java
@@ -0,0 +1,40 @@
+package com.thealgorithms.sorts;
+
+public class AdaptiveMergeSort implements SortAlgorithm {
+    @SuppressWarnings("unchecked")
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array.length <= 1) {
+            return array;
+        }
+        T[] aux = array.clone();
+        sort(array, aux, 0, array.length - 1);
+        return array;
+    }
+
+    private <T extends Comparable<T>> void sort(T[] array, T[] aux, int low, int high) {
+        if (low >= high) {
+            return;
+        }
+        int mid = low + (high - low) / 2;
+        sort(array, aux, low, mid);
+        sort(array, aux, mid + 1, high);
+        merge(array, aux, low, mid, high);
+    }
+
+    private <T extends Comparable<T>> void merge(T[] array, T[] aux, int low, int mid, int high) {
+        System.arraycopy(array, low, aux, low, high - low + 1);
+        int i = low;
+        int j = mid + 1;
+        for (int k = low; k <= high; k++) {
+            if (i > mid) {
+                array[k] = aux[j++];
+            } else if (j > high) {
+                array[k] = aux[i++];
+            } else if (aux[j].compareTo(aux[i]) < 0) {
+                array[k] = aux[j++];
+            } else {
+                array[k] = aux[i++];
+            }
+        }
+    }
+}
diff --git a/src/main/java/com/thealgorithms/sorts/StalinSort.java b/src/main/java/com/thealgorithms/sorts/StalinSort.java
new file mode 100644
index 000000000000..5aaf530fd94c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/StalinSort.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.sorts;
+
+public class StalinSort implements SortAlgorithm {
+    @SuppressWarnings("unchecked")
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array.length == 0) {
+            return array;
+        }
+        int currentIndex = 0;
+        for (int i = 1; i < array.length; i++) {
+            if (array[i].compareTo(array[currentIndex]) >= 0) {
+                currentIndex++;
+                array[currentIndex] = array[i];
+            }
+        }
+        // Create a result array with sorted elements
+        T[] result = (T[]) java.lang.reflect.Array.newInstance(array.getClass().getComponentType(), currentIndex + 1);
+        System.arraycopy(array, 0, result, 0, currentIndex + 1);
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java b/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java
new file mode 100644
index 000000000000..9d94b165d81b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class AdaptiveMergeSortTest {
+
+    @Test
+    public void testSortIntegers() {
+        AdaptiveMergeSort adaptiveMergeSort = new AdaptiveMergeSort();
+        Integer[] input = {4, 23, 6, 78, 1, 54, 231, 9, 12};
+        Integer[] expected = {1, 4, 6, 9, 12, 23, 54, 78, 231};
+        Integer[] result = adaptiveMergeSort.sort(input);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testSortStrings() {
+        AdaptiveMergeSort adaptiveMergeSort = new AdaptiveMergeSort();
+        String[] input = {"c", "a", "e", "b", "d"};
+        String[] expected = {"a", "b", "c", "d", "e"};
+        String[] result = adaptiveMergeSort.sort(input);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testSortWithDuplicates() {
+        AdaptiveMergeSort adaptiveMergeSort = new AdaptiveMergeSort();
+        Integer[] input = {1, 3, 2, 2, 5, 4};
+        Integer[] expected = {1, 2, 2, 3, 4, 5};
+        Integer[] result = adaptiveMergeSort.sort(input);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testSortEmptyArray() {
+        AdaptiveMergeSort adaptiveMergeSort = new AdaptiveMergeSort();
+        Integer[] input = {};
+        Integer[] expected = {};
+        Integer[] result = adaptiveMergeSort.sort(input);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testSortSingleElement() {
+        AdaptiveMergeSort adaptiveMergeSort = new AdaptiveMergeSort();
+        Integer[] input = {42};
+        Integer[] expected = {42};
+        Integer[] result = adaptiveMergeSort.sort(input);
+        assertArrayEquals(expected, result);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/StalinSortTest.java b/src/test/java/com/thealgorithms/sorts/StalinSortTest.java
new file mode 100644
index 000000000000..ee9c61379527
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/StalinSortTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class StalinSortTest {
+
+    @Test
+    public void testSortIntegers() {
+        StalinSort stalinSort = new StalinSort();
+        Integer[] input = {4, 23, 6, 78, 1, 54, 231, 9, 12};
+        Integer[] expected = {4, 23, 78, 231};
+        Integer[] result = stalinSort.sort(input);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testSortStrings() {
+        StalinSort stalinSort = new StalinSort();
+        String[] input = {"c", "a", "e", "b", "d"};
+        String[] expected = {"c", "e"};
+        String[] result = stalinSort.sort(input);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testSortWithDuplicates() {
+        StalinSort stalinSort = new StalinSort();
+        Integer[] input = {1, 3, 2, 2, 5, 4};
+        Integer[] expected = {1, 3, 5};
+        Integer[] result = stalinSort.sort(input);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testSortEmptyArray() {
+        StalinSort stalinSort = new StalinSort();
+        Integer[] input = {};
+        Integer[] expected = {};
+        Integer[] result = stalinSort.sort(input);
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    public void testSortSingleElement() {
+        StalinSort stalinSort = new StalinSort();
+        Integer[] input = {42};
+        Integer[] expected = {42};
+        Integer[] result = stalinSort.sort(input);
+        assertArrayEquals(expected, result);
+    }
+}

From efb16c1eff0153ee81da7b6aafca1932f36dd722 Mon Sep 17 00:00:00 2001
From: PANKAJ PATWAL <120747214+Chiefpatwal@users.noreply.github.com>
Date: Tue, 22 Oct 2024 23:20:47 +0530
Subject: [PATCH 0578/1338] Add edge case to handle negative rod length in
 RodCutting algorithm (#5904)

---
 .../com/thealgorithms/dynamicprogramming/RodCutting.java    | 4 ++++
 .../thealgorithms/dynamicprogramming/RodCuttingTest.java    | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java b/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
index 76b341e2c823..6d33826b6b17 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java
@@ -22,6 +22,10 @@ public static int cutRod(int[] price, int n) {
         if (price == null || price.length == 0) {
             throw new IllegalArgumentException("Price array cannot be null or empty.");
         }
+        if (n < 0) {
+            throw new IllegalArgumentException("Rod length cannot be negative.");
+        }
+
         // Create an array to store the maximum obtainable values for each rod length.
         int[] val = new int[n + 1];
         val[0] = 0;
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java
index 39497a768397..9cf21fd836db 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java
@@ -93,4 +93,10 @@ void testCutRodEmptyPrices() {
         int length = 5;
         assertThrows(IllegalArgumentException.class, () -> RodCutting.cutRod(prices, length), "An empty prices array should throw an IllegalArgumentException.");
     }
+    @Test
+    void testCutRodNegativeLength() {
+        int[] prices = {1, 5, 8, 9, 10}; // Prices are irrelevant for negative length
+        int length = -1;
+        assertThrows(IllegalArgumentException.class, () -> RodCutting.cutRod(prices, length), "A negative rod length should throw an IllegalArgumentException.");
+    }
 }

From ef72b1e40b4be91ed7489c2d572872af4ea3c3fd Mon Sep 17 00:00:00 2001
From: Tanmay Singh <156223260+Tanmay-Singh3004@users.noreply.github.com>
Date: Tue, 22 Oct 2024 23:24:45 +0530
Subject: [PATCH 0579/1338] Remove main function, improve docstring, add JUnit
 tests for `KrishnamurthyNumber`. (#5881)

---
 DIRECTORY.md                                  |  1 +
 .../maths/KrishnamurthyNumber.java            | 52 +++++++---------
 .../maths/KrishnamurthyNumberTest.java        | 62 +++++++++++++++++++
 3 files changed, 87 insertions(+), 28 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index e511ab40b329..3d5b2bf61d6a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -982,6 +982,7 @@
             * [JosephusProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/JosephusProblemTest.java)
             * [KaprekarNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java)
             * [KaratsubaMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java)
+            * [KrishnamurthyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java)
             * [LeastCommonMultipleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java)
             * [LeonardoNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java)
             * [LiouvilleLambdaFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java)
diff --git a/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java b/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
index f5ff50337bc7..03f18aca786f 100644
--- a/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
@@ -1,31 +1,38 @@
 package com.thealgorithms.maths;
 
-/* This is a program to check if a number is a Krishnamurthy number or not.
-A number is a Krishnamurthy number if the sum of the factorials of the digits of the number is equal
-to the number itself. For example, 1, 2 and 145 are Krishnamurthy numbers. Krishnamurthy number is
-also referred to as a Strong number.
+/**
+ * Utility class for checking if a number is a Krishnamurthy number.
+ *
+ * A Krishnamurthy number (also known as a Strong number) is a number whose sum of the factorials of its digits is equal to the number itself.
+ *
+ * For example, 145 is a Krishnamurthy number because 1! + 4! + 5! = 1 + 24 + 120 = 145.
+ * <b>Example usage:</b>
+ * <pre>
+ * boolean isKrishnamurthy = KrishnamurthyNumber.isKrishnamurthy(145);
+ * System.out.println(isKrishnamurthy); // Output: true
+ *
+ * isKrishnamurthy = KrishnamurthyNumber.isKrishnamurthy(123);
+ * System.out.println(isKrishnamurthy); // Output: false
+ * </pre>
  */
-import java.io.BufferedReader;
-import java.io.IOException;
-import java.io.InputStreamReader;
-
 public final class KrishnamurthyNumber {
+
     private KrishnamurthyNumber() {
     }
 
-    // returns True if the number is a Krishnamurthy number and False if it is not.
-
-    public static boolean isKMurthy(int n) {
-        // initialising the variable s that will store the sum of the factorials of the digits to 0
-        int s = 0;
-        // storing the number n in a temporary variable tmp
+    /**
+     * Checks if a number is a Krishnamurthy number.
+     *
+     * @param n The number to check
+     * @return true if the number is a Krishnamurthy number, false otherwise
+     */
+    public static boolean isKrishnamurthy(int n) {
         int tmp = n;
+        int s = 0;
 
-        // Krishnamurthy numbers are positive
         if (n <= 0) {
             return false;
-        } // checking if the number is a Krishnamurthy number
-        else {
+        } else {
             while (n != 0) {
                 // initialising the variable fact that will store the factorials of the digits
                 int fact = 1;
@@ -43,15 +50,4 @@ public static boolean isKMurthy(int n) {
             return tmp == s;
         }
     }
-
-    public static void main(String[] args) throws IOException {
-        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
-        System.out.println("Enter a number to check if it is a Krishnamurthy number: ");
-        int n = Integer.parseInt(br.readLine());
-        if (isKMurthy(n)) {
-            System.out.println(n + " is a Krishnamurthy number.");
-        } else {
-            System.out.println(n + " is NOT a Krishnamurthy number.");
-        }
-    }
 }
diff --git a/src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java b/src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java
new file mode 100644
index 000000000000..595acde2b5d8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java
@@ -0,0 +1,62 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the KrishnamurthyNumber class.
+ */
+public class KrishnamurthyNumberTest {
+
+    /**
+     * Test the isKrishnamurthy method with a known Krishnamurthy number.
+     */
+    @Test
+    public void testIsKrishnamurthyTrue() {
+        assertTrue(KrishnamurthyNumber.isKrishnamurthy(145));
+    }
+
+    /**
+     * Test the isKrishnamurthy method with a number that is not a Krishnamurthy number.
+     */
+    @Test
+    public void testIsKrishnamurthyFalse() {
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(123));
+    }
+
+    /**
+     * Test the isKrishnamurthy method with zero.
+     */
+    @Test
+    public void testIsKrishnamurthyZero() {
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(0));
+    }
+
+    /**
+     * Test the isKrishnamurthy method with a negative number.
+     */
+    @Test
+    public void testIsKrishnamurthyNegative() {
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(-145));
+    }
+
+    /**
+     * Test the isKrishnamurthy method with a single-digit Krishnamurthy number.
+     */
+    @Test
+    public void testIsKrishnamurthySingleDigitTrue() {
+        assertTrue(KrishnamurthyNumber.isKrishnamurthy(1));
+        assertTrue(KrishnamurthyNumber.isKrishnamurthy(2));
+    }
+
+    /**
+     * Test the isKrishnamurthy method with a single-digit number that is not a Krishnamurthy number.
+     */
+    @Test
+    public void testIsKrishnamurthySingleDigitFalse() {
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(3));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(4));
+    }
+}

From 0bb22fbc7da5358993c6d8613079ab33fd370e0a Mon Sep 17 00:00:00 2001
From: Tanmay Singh <156223260+Tanmay-Singh3004@users.noreply.github.com>
Date: Tue, 22 Oct 2024 23:34:00 +0530
Subject: [PATCH 0580/1338] Remove main function from GCD class (#5828)

---
 .../java/com/thealgorithms/maths/GCD.java     | 28 +++++++++++--------
 .../java/com/thealgorithms/maths/GCDTest.java |  5 ++++
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/GCD.java b/src/main/java/com/thealgorithms/maths/GCD.java
index 5156e4ac881d..df27516367b2 100644
--- a/src/main/java/com/thealgorithms/maths/GCD.java
+++ b/src/main/java/com/thealgorithms/maths/GCD.java
@@ -1,9 +1,23 @@
 package com.thealgorithms.maths;
 
 /**
- * This is Euclid's algorithm, used to find the greatest common
- * denominator Override function name gcd
+ *  This class provides methods to compute the Greatest Common Divisor (GCD) of two or more integers.
  *
+ * The Greatest Common Divisor (GCD) of two or more integers is the largest positive integer that divides each of the integers without leaving a remainder.
+ *
+ * The GCD can be computed using the Euclidean algorithm, which is based on the principle that the GCD of two numbers also divides their difference.
+ *
+ * For more information, refer to the
+ * <a href="https://en.wikipedia.org/wiki/Greatest_common_divisor">Greatest Common Divisor</a> Wikipedia page.
+ *
+ * <b>Example usage:</b>
+ * <pre>
+ * int result1 = GCD.gcd(48, 18);
+ * System.out.println("GCD of 48 and 18: " + result1); // Output: 6
+ *
+ * int result2 = GCD.gcd(48, 18, 30);
+ * System.out.println("GCD of 48, 18, and 30: " + result2); // Output: 6
+ * </pre>
  * @author Oskar Enmalm 3/10/17
  */
 public final class GCD {
@@ -40,7 +54,7 @@ public static int gcd(int num1, int num2) {
      * @param numbers the input array
      * @return gcd of all of the numbers in the input array
      */
-    public static int gcd(int[] numbers) {
+    public static int gcd(int... numbers) {
         int result = 0;
         for (final var number : numbers) {
             result = gcd(result, number);
@@ -48,12 +62,4 @@ public static int gcd(int[] numbers) {
 
         return result;
     }
-
-    public static void main(String[] args) {
-        int[] myIntArray = {4, 16, 32};
-
-        // call gcd function (input array)
-        System.out.println(gcd(myIntArray)); // => 4
-        System.out.printf("gcd(40,24)=%d gcd(24,40)=%d%n", gcd(40, 24), gcd(24, 40)); // => 8
-    }
 }
diff --git a/src/test/java/com/thealgorithms/maths/GCDTest.java b/src/test/java/com/thealgorithms/maths/GCDTest.java
index 5a659664fd29..bac3f8f7596c 100644
--- a/src/test/java/com/thealgorithms/maths/GCDTest.java
+++ b/src/test/java/com/thealgorithms/maths/GCDTest.java
@@ -40,6 +40,11 @@ void test7() {
         Assertions.assertEquals(GCD.gcd(9, 6), 3);
     }
 
+    @Test
+    void test8() {
+        Assertions.assertEquals(GCD.gcd(48, 18, 30, 12), 6);
+    }
+
     @Test
     void testArrayGcd1() {
         Assertions.assertEquals(GCD.gcd(new int[] {9, 6}), 3);

From 5a1f681234c45e380cbeb76bb81027acffeb791b Mon Sep 17 00:00:00 2001
From: Manish Raj <2200032955@kluniversity.in>
Date: Tue, 22 Oct 2024 23:37:19 +0530
Subject: [PATCH 0581/1338] Optimize BreadthFirstSearch implementation (#5882)

---
 .../searches/BreadthFirstSearch.java          | 52 +++++++++++++------
 1 file changed, 37 insertions(+), 15 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java b/src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java
index debab98c67a8..7ac9c7b01526 100644
--- a/src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java
+++ b/src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java
@@ -3,37 +3,54 @@
 import com.thealgorithms.datastructures.Node;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Optional;
 import java.util.Queue;
+import java.util.Set;
 
 /**
- * @author: caos321
- * @date: 31 October 2021 (Sunday)
- * @wiki: https://en.wikipedia.org/wiki/Breadth-first_search
+ * Breadth-First Search implementation for tree/graph traversal.
+ * @author caos321
+ * @co-author @manishraj27
+ * @see <a href="https://en.wikipedia.org/wiki/Breadth-first_search">Breadth-first search</a>
  */
 public class BreadthFirstSearch<T> {
-
     private final List<T> visited = new ArrayList<>();
+    private final Set<T> visitedSet = new HashSet<>();
 
-    public Optional<Node<T>> search(final Node<T> node, final T value) {
-        if (node == null) {
+    /**
+     * Performs a breadth-first search to find a node with the given value.
+     *
+     * @param root The root node to start the search from
+     * @param value The value to search for
+     * @return Optional containing the found node, or empty if not found
+     */
+    public Optional<Node<T>> search(final Node<T> root, final T value) {
+        if (root == null) {
             return Optional.empty();
         }
-        if (node.getValue().equals(value)) {
-            // add root node to visited
-            visited.add(value);
-            return Optional.of(node);
-        }
-        visited.add(node.getValue());
 
-        Queue<Node<T>> queue = new ArrayDeque<>(node.getChildren());
+        visited.add(root.getValue());
+        visitedSet.add(root.getValue());
+
+        if (root.getValue() == value) {
+            return Optional.of(root);
+        }
 
+        Queue<Node<T>> queue = new ArrayDeque<>(root.getChildren());
         while (!queue.isEmpty()) {
             final Node<T> current = queue.poll();
-            visited.add(current.getValue());
+            T currentValue = current.getValue();
+
+            if (visitedSet.contains(currentValue)) {
+                continue;
+            }
+
+            visited.add(currentValue);
+            visitedSet.add(currentValue);
 
-            if (current.getValue().equals(value)) {
+            if (currentValue == value || (value != null && value.equals(currentValue))) {
                 return Optional.of(current);
             }
 
@@ -43,6 +60,11 @@ public Optional<Node<T>> search(final Node<T> node, final T value) {
         return Optional.empty();
     }
 
+    /**
+     * Returns the list of nodes in the order they were visited.
+     *
+     * @return List containing the visited nodes
+     */
     public List<T> getVisited() {
         return visited;
     }

From c56d282ae092810327bc18b6083d552a91b9eb8e Mon Sep 17 00:00:00 2001
From: Ritisha Pande <96540421+riti2601@users.noreply.github.com>
Date: Tue, 22 Oct 2024 23:46:35 +0530
Subject: [PATCH 0582/1338] Add DiffieHellman and MonoAlphabetic (#5508)

---
 .../thealgorithms/ciphers/DiffieHellman.java  | 36 ++++++++++++++
 .../thealgorithms/ciphers/MonoAlphabetic.java | 48 +++++++++++++++++++
 .../ciphers/DiffieHellmanTest.java            | 38 +++++++++++++++
 .../ciphers/MonoAlphabeticTest.java           | 29 +++++++++++
 4 files changed, 151 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/DiffieHellman.java
 create mode 100644 src/main/java/com/thealgorithms/ciphers/MonoAlphabetic.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/DiffieHellmanTest.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/MonoAlphabeticTest.java

diff --git a/src/main/java/com/thealgorithms/ciphers/DiffieHellman.java b/src/main/java/com/thealgorithms/ciphers/DiffieHellman.java
new file mode 100644
index 000000000000..7470b40e001a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/DiffieHellman.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.ciphers;
+
+import java.math.BigInteger;
+
+public final class DiffieHellman {
+
+    private final BigInteger base;
+    private final BigInteger secret;
+    private final BigInteger prime;
+
+    // Constructor to initialize base, secret, and prime
+    public DiffieHellman(BigInteger base, BigInteger secret, BigInteger prime) {
+        // Check for non-null and positive values
+        if (base == null || secret == null || prime == null || base.signum() <= 0 || secret.signum() <= 0 || prime.signum() <= 0) {
+            throw new IllegalArgumentException("Base, secret, and prime must be non-null and positive values.");
+        }
+        this.base = base;
+        this.secret = secret;
+        this.prime = prime;
+    }
+
+    // Method to calculate public value (g^x mod p)
+    public BigInteger calculatePublicValue() {
+        // Returns g^x mod p
+        return base.modPow(secret, prime);
+    }
+
+    // Method to calculate the shared secret key (otherPublic^secret mod p)
+    public BigInteger calculateSharedSecret(BigInteger otherPublicValue) {
+        if (otherPublicValue == null || otherPublicValue.signum() <= 0) {
+            throw new IllegalArgumentException("Other public value must be non-null and positive.");
+        }
+        // Returns b^x mod p or a^y mod p
+        return otherPublicValue.modPow(secret, prime);
+    }
+}
diff --git a/src/main/java/com/thealgorithms/ciphers/MonoAlphabetic.java b/src/main/java/com/thealgorithms/ciphers/MonoAlphabetic.java
new file mode 100644
index 000000000000..1d5b7110a6f3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/MonoAlphabetic.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.ciphers;
+
+public final class MonoAlphabetic {
+
+    private MonoAlphabetic() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    // Encryption method
+    public static String encrypt(String data, String key) {
+        if (!data.matches("[A-Z]+")) {
+            throw new IllegalArgumentException("Input data contains invalid characters. Only uppercase A-Z are allowed.");
+        }
+        StringBuilder sb = new StringBuilder();
+
+        // Encrypt each character
+        for (char c : data.toCharArray()) {
+            int idx = charToPos(c); // Get the index of the character
+            sb.append(key.charAt(idx)); // Map to the corresponding character in the key
+        }
+        return sb.toString();
+    }
+
+    // Decryption method
+    public static String decrypt(String data, String key) {
+        StringBuilder sb = new StringBuilder();
+
+        // Decrypt each character
+        for (char c : data.toCharArray()) {
+            int idx = key.indexOf(c); // Find the index of the character in the key
+            if (idx == -1) {
+                throw new IllegalArgumentException("Input data contains invalid characters.");
+            }
+            sb.append(posToChar(idx)); // Convert the index back to the original character
+        }
+        return sb.toString();
+    }
+
+    // Helper method: Convert a character to its position in the alphabet
+    private static int charToPos(char c) {
+        return c - 'A'; // Subtract 'A' to get position (0 for A, 1 for B, etc.)
+    }
+
+    // Helper method: Convert a position in the alphabet to a character
+    private static char posToChar(int pos) {
+        return (char) (pos + 'A'); // Add 'A' to convert position back to character
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/DiffieHellmanTest.java b/src/test/java/com/thealgorithms/ciphers/DiffieHellmanTest.java
new file mode 100644
index 000000000000..6255ad22ab56
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/DiffieHellmanTest.java
@@ -0,0 +1,38 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.math.BigInteger;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class DiffieHellmanTest {
+
+    // Test for public value calculation using instance methods
+    @ParameterizedTest
+    @MethodSource("provideTestData")
+    public void testCalculatePublicValue(BigInteger base, BigInteger secret, BigInteger prime, BigInteger publicExpected, BigInteger sharedExpected) {
+        DiffieHellman dh = new DiffieHellman(base, secret, prime); // Create an instance of DiffieHellman
+        assertEquals(publicExpected, dh.calculatePublicValue()); // Call instance method
+    }
+
+    // Test for shared secret calculation using instance methods
+    @ParameterizedTest
+    @MethodSource("provideTestData")
+    public void testCalculateSharedSecret(BigInteger base, BigInteger secret, BigInteger prime, BigInteger publicExpected, BigInteger sharedExpected) {
+        DiffieHellman dh = new DiffieHellman(base, secret, prime); // Create an instance of DiffieHellman
+        assertEquals(sharedExpected, dh.calculateSharedSecret(publicExpected)); // Call instance method
+    }
+
+    // Provide test data for both public key and shared secret calculation
+    private static Stream<Arguments> provideTestData() {
+        return Stream.of(createTestArgs(5, 6, 23, 8, 13), createTestArgs(2, 5, 13, 6, 2));
+    }
+
+    // Helper method for arguments
+    private static Arguments createTestArgs(long base, long secret, long prime, long publicExpected, long sharedExpected) {
+        return Arguments.of(BigInteger.valueOf(base), BigInteger.valueOf(secret), BigInteger.valueOf(prime), BigInteger.valueOf(publicExpected), BigInteger.valueOf(sharedExpected));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/MonoAlphabeticTest.java b/src/test/java/com/thealgorithms/ciphers/MonoAlphabeticTest.java
new file mode 100644
index 000000000000..b1a8c78c952e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/MonoAlphabeticTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class MonoAlphabeticTest {
+
+    // Test for both encryption and decryption with different keys
+    @ParameterizedTest
+    @MethodSource("provideTestData")
+    public void testEncryptDecrypt(String plainText, String key, String encryptedText) {
+        // Test encryption
+        String actualEncrypted = MonoAlphabetic.encrypt(plainText, key);
+        assertEquals(encryptedText, actualEncrypted, "Encryption failed for input: " + plainText + " with key: " + key);
+
+        // Test decryption
+        String actualDecrypted = MonoAlphabetic.decrypt(encryptedText, key);
+        assertEquals(plainText, actualDecrypted, "Decryption failed for input: " + encryptedText + " with key: " + key);
+    }
+
+    // Provide test data for both encryption and decryption
+    private static Stream<Arguments> provideTestData() {
+        return Stream.of(Arguments.of("HELLO", "MNBVCXZLKJHGFDSAPOIUYTREWQ", "LCGGS"), Arguments.of("JAVA", "MNBVCXZLKJHGFDSAPOIUYTREWQ", "JMTM"), Arguments.of("HELLO", "QWERTYUIOPLKJHGFDSAZXCVBNM", "ITKKG"), Arguments.of("JAVA", "QWERTYUIOPLKJHGFDSAZXCVBNM", "PQCQ"));
+    }
+}

From 87030aff1eb7b7a41d61cf8395571f91f69ffdc3 Mon Sep 17 00:00:00 2001
From: Benjamin Burstein <98127047+bennybebo@users.noreply.github.com>
Date: Tue, 22 Oct 2024 14:30:37 -0400
Subject: [PATCH 0583/1338] Add BaconianCipher (#5932)

---
 .../thealgorithms/ciphers/BaconianCipher.java | 71 +++++++++++++++++++
 .../ciphers/BaconianCipherTest.java           | 34 +++++++++
 2 files changed, 105 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/BaconianCipher.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/BaconianCipherTest.java

diff --git a/src/main/java/com/thealgorithms/ciphers/BaconianCipher.java b/src/main/java/com/thealgorithms/ciphers/BaconianCipher.java
new file mode 100644
index 000000000000..16dfd6e674af
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/BaconianCipher.java
@@ -0,0 +1,71 @@
+package com.thealgorithms.ciphers;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * The Baconian Cipher is a substitution cipher where each letter is represented
+ * by a group of five binary digits (A's and B's). It can also be used to hide
+ * messages within other texts, making it a simple form of steganography.
+ * https://en.wikipedia.org/wiki/Bacon%27s_cipher
+ *
+ * @author Bennybebo
+ */
+public class BaconianCipher {
+
+    private static final Map<Character, String> BACONIAN_MAP = new HashMap<>();
+    private static final Map<String, Character> REVERSE_BACONIAN_MAP = new HashMap<>();
+
+    static {
+        // Initialize the Baconian cipher mappings
+        String[] baconianAlphabet = {"AAAAA", "AAAAB", "AAABA", "AAABB", "AABAA", "AABAB", "AABBA", "AABBB", "ABAAA", "ABAAB", "ABABA", "ABABB", "ABBAA", "ABBAB", "ABBBA", "ABBBB", "BAAAA", "BAAAB", "BAABA", "BAABB", "BABAA", "BABAB", "BABBA", "BABBB", "BBAAA", "BBAAB"};
+        char letter = 'A';
+        for (String code : baconianAlphabet) {
+            BACONIAN_MAP.put(letter, code);
+            REVERSE_BACONIAN_MAP.put(code, letter);
+            letter++;
+        }
+
+        // Handle I/J as the same letter
+        BACONIAN_MAP.put('I', BACONIAN_MAP.get('J'));
+        REVERSE_BACONIAN_MAP.put(BACONIAN_MAP.get('I'), 'I');
+    }
+
+    /**
+     * Encrypts the given plaintext using the Baconian cipher.
+     *
+     * @param plaintext The plaintext message to encrypt.
+     * @return The ciphertext as a binary (A/B) sequence.
+     */
+    public String encrypt(String plaintext) {
+        StringBuilder ciphertext = new StringBuilder();
+        plaintext = plaintext.toUpperCase().replaceAll("[^A-Z]", ""); // Remove non-letter characters
+
+        for (char letter : plaintext.toCharArray()) {
+            ciphertext.append(BACONIAN_MAP.get(letter));
+        }
+
+        return ciphertext.toString();
+    }
+
+    /**
+     * Decrypts the given ciphertext encoded in binary (A/B) format using the Baconian cipher.
+     *
+     * @param ciphertext The ciphertext to decrypt.
+     * @return The decrypted plaintext message.
+     */
+    public String decrypt(String ciphertext) {
+        StringBuilder plaintext = new StringBuilder();
+
+        for (int i = 0; i < ciphertext.length(); i += 5) {
+            String code = ciphertext.substring(i, i + 5);
+            if (REVERSE_BACONIAN_MAP.containsKey(code)) {
+                plaintext.append(REVERSE_BACONIAN_MAP.get(code));
+            } else {
+                throw new IllegalArgumentException("Invalid Baconian code: " + code);
+            }
+        }
+
+        return plaintext.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/BaconianCipherTest.java b/src/test/java/com/thealgorithms/ciphers/BaconianCipherTest.java
new file mode 100644
index 000000000000..bb1ae5a7e4c2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/BaconianCipherTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class BaconianCipherTest {
+
+    BaconianCipher baconianCipher = new BaconianCipher();
+
+    @Test
+    void baconianCipherEncryptTest() {
+        // given
+        String plaintext = "MEET AT DAWN";
+
+        // when
+        String cipherText = baconianCipher.encrypt(plaintext);
+
+        // then
+        assertEquals("ABBAAAABAAAABAABAABBAAAAABAABBAAABBAAAAABABBAABBAB", cipherText);
+    }
+
+    @Test
+    void baconianCipherDecryptTest() {
+        // given
+        String ciphertext = "ABBAAAABAAAABAABAABBAAAAABAABBAAABBAAAAABABBAABBAB";
+
+        // when
+        String plainText = baconianCipher.decrypt(ciphertext);
+
+        // then
+        assertEquals("MEETATDAWN", plainText);
+    }
+}

From 0f8cda987d57763040f45dbfc4f9b107f9b56bdb Mon Sep 17 00:00:00 2001
From: S M Jishanul Islam <sislam201024@bscse.uiu.ac.bd>
Date: Wed, 23 Oct 2024 00:36:14 +0600
Subject: [PATCH 0584/1338] Add the retrieval of minimum and maximum element
 from stack at O(1) (#5714)

---
 .../stacks/GreatestElementConstantTime.java   | 74 +++++++++++++++++++
 .../stacks/SmallestElementConstantTime.java   | 74 +++++++++++++++++++
 .../GreatestElementConstantTimeTest.java      | 70 ++++++++++++++++++
 .../SmallestElementConstantTimeTest.java      | 69 +++++++++++++++++
 4 files changed, 287 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/GreatestElementConstantTime.java
 create mode 100644 src/main/java/com/thealgorithms/stacks/SmallestElementConstantTime.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/GreatestElementConstantTimeTest.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/SmallestElementConstantTimeTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/GreatestElementConstantTime.java b/src/main/java/com/thealgorithms/stacks/GreatestElementConstantTime.java
new file mode 100644
index 000000000000..be9d0099d38b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/GreatestElementConstantTime.java
@@ -0,0 +1,74 @@
+package com.thealgorithms.stacks;
+
+import java.util.NoSuchElementException;
+import java.util.Stack;
+
+/**
+ * A class that implements a stack that gives the maximum element in O(1) time.
+ * The mainStack is used to store the all the elements of the stack
+ * While the maxStack stores the maximum elements
+ * When we want to get a maximum element, we call the top of the maximum stack
+ *
+ * Problem: https://www.baeldung.com/cs/stack-constant-time
+ */
+public class GreatestElementConstantTime {
+    private Stack<Integer> mainStack; // initialize a mainStack
+    private Stack<Integer> maxStack; // initialize a maxStack
+
+    /**
+     * Constructs two empty stacks
+     */
+    public GreatestElementConstantTime() {
+        mainStack = new Stack<>();
+        maxStack = new Stack<>();
+    }
+
+    /**
+     * Pushes an element onto the top of the stack.
+     * Checks if the element is the maximum or not
+     * If so, then pushes to the maximum stack
+     * @param data The element to be pushed onto the stack.
+     */
+    public void push(int data) {
+        if (mainStack.isEmpty()) {
+            mainStack.push(data);
+            maxStack.push(data);
+            return;
+        }
+
+        mainStack.push(data);
+        if (data > maxStack.peek()) {
+            maxStack.push(data);
+        }
+    }
+
+    /**
+     * Pops an element from the stack.
+     * Checks if the element to be popped is the maximum or not
+     * If so, then pop from the minStack
+     *
+     * @throws NoSuchElementException if the stack is empty.
+     */
+    public void pop() {
+        if (mainStack.isEmpty()) {
+            throw new NoSuchElementException("Stack is empty");
+        }
+
+        int ele = mainStack.pop();
+        if (ele == maxStack.peek()) {
+            maxStack.pop();
+        }
+    }
+
+    /**
+     * Returns the maximum element present in the stack
+     *
+     * @return The element at the top of the maxStack, or null if the stack is empty.
+     */
+    public Integer getMaximumElement() {
+        if (maxStack.isEmpty()) {
+            return null;
+        }
+        return maxStack.peek();
+    }
+}
diff --git a/src/main/java/com/thealgorithms/stacks/SmallestElementConstantTime.java b/src/main/java/com/thealgorithms/stacks/SmallestElementConstantTime.java
new file mode 100644
index 000000000000..9864ef9b0f97
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/SmallestElementConstantTime.java
@@ -0,0 +1,74 @@
+package com.thealgorithms.stacks;
+
+import java.util.NoSuchElementException;
+import java.util.Stack;
+
+/**
+ * A class that implements a stack that gives the minimum element in O(1) time.
+ * The mainStack is used to store the all the elements of the stack
+ * While the minStack stores the minimum elements
+ * When we want to get a minimum element, we call the top of the minimum stack
+ *
+ * Problem: https://www.baeldung.com/cs/stack-constant-time
+ */
+public class SmallestElementConstantTime {
+    private Stack<Integer> mainStack; // initialize a mainStack
+    private Stack<Integer> minStack; // initialize a minStack
+
+    /**
+     * Constructs two empty stacks
+     */
+    public SmallestElementConstantTime() {
+        mainStack = new Stack<>();
+        minStack = new Stack<>();
+    }
+
+    /**
+     * Pushes an element onto the top of the stack.
+     * Checks if the element is the minimum or not
+     * If so, then pushes to the minimum stack
+     * @param data The element to be pushed onto the stack.
+     */
+    public void push(int data) {
+        if (mainStack.isEmpty()) {
+            mainStack.push(data);
+            minStack.push(data);
+            return;
+        }
+
+        mainStack.push(data);
+        if (data < minStack.peek()) {
+            minStack.push(data);
+        }
+    }
+
+    /**
+     * Pops an element from the stack.
+     * Checks if the element to be popped is the minimum or not
+     * If so, then pop from the minStack
+     *
+     * @throws NoSuchElementException if the stack is empty.
+     */
+    public void pop() {
+        if (mainStack.isEmpty()) {
+            throw new NoSuchElementException("Stack is empty");
+        }
+
+        int ele = mainStack.pop();
+        if (ele == minStack.peek()) {
+            minStack.pop();
+        }
+    }
+
+    /**
+     * Returns the minimum element present in the stack
+     *
+     * @return The element at the top of the minStack, or null if the stack is empty.
+     */
+    public Integer getMinimumElement() {
+        if (minStack.isEmpty()) {
+            return null;
+        }
+        return minStack.peek();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/GreatestElementConstantTimeTest.java b/src/test/java/com/thealgorithms/stacks/GreatestElementConstantTimeTest.java
new file mode 100644
index 000000000000..080592dc68e8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/GreatestElementConstantTimeTest.java
@@ -0,0 +1,70 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.NoSuchElementException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class GreatestElementConstantTimeTest {
+
+    private GreatestElementConstantTime constantTime;
+
+    @BeforeEach
+    public void setConstantTime() {
+        constantTime = new GreatestElementConstantTime();
+    }
+
+    @Test
+    public void testMaxAtFirst() {
+        constantTime.push(1);
+        constantTime.push(10);
+        constantTime.push(20);
+        constantTime.push(5);
+        assertEquals(20, constantTime.getMaximumElement());
+    }
+
+    @Test
+    public void testMinTwo() {
+        constantTime.push(5);
+        constantTime.push(10);
+        constantTime.push(20);
+        constantTime.push(1);
+        assertEquals(20, constantTime.getMaximumElement());
+        constantTime.pop();
+        constantTime.pop();
+        assertEquals(10, constantTime.getMaximumElement());
+    }
+
+    @Test
+    public void testNullMax() {
+        constantTime.push(10);
+        constantTime.push(20);
+        constantTime.pop();
+        constantTime.pop();
+        assertNull(constantTime.getMaximumElement());
+    }
+
+    @Test
+    public void testBlankHandle() {
+        constantTime.push(10);
+        constantTime.push(1);
+        constantTime.pop();
+        constantTime.pop();
+        assertThrows(NoSuchElementException.class, () -> constantTime.pop());
+    }
+
+    @Test
+    public void testPushPopAfterEmpty() {
+        constantTime.push(10);
+        constantTime.push(1);
+        constantTime.pop();
+        constantTime.pop();
+        constantTime.push(5);
+        assertEquals(5, constantTime.getMaximumElement());
+        constantTime.push(1);
+        assertEquals(5, constantTime.getMaximumElement());
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/SmallestElementConstantTimeTest.java b/src/test/java/com/thealgorithms/stacks/SmallestElementConstantTimeTest.java
new file mode 100644
index 000000000000..b5eda9e8cb46
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/SmallestElementConstantTimeTest.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.NoSuchElementException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class SmallestElementConstantTimeTest {
+
+    private SmallestElementConstantTime sect;
+
+    @BeforeEach
+    public void setSect() {
+        sect = new SmallestElementConstantTime();
+    }
+
+    @Test
+    public void testMinAtFirst() {
+        sect.push(1);
+        sect.push(10);
+        sect.push(20);
+        sect.push(5);
+        assertEquals(1, sect.getMinimumElement());
+    }
+
+    @Test
+    public void testMinTwo() {
+        sect.push(5);
+        sect.push(10);
+        sect.push(20);
+        sect.push(1);
+        assertEquals(1, sect.getMinimumElement());
+        sect.pop();
+        assertEquals(5, sect.getMinimumElement());
+    }
+
+    @Test
+    public void testNullMin() {
+        sect.push(10);
+        sect.push(20);
+        sect.pop();
+        sect.pop();
+        assertNull(sect.getMinimumElement());
+    }
+
+    @Test
+    public void testBlankHandle() {
+        sect.push(10);
+        sect.push(1);
+        sect.pop();
+        sect.pop();
+        assertThrows(NoSuchElementException.class, () -> sect.pop());
+    }
+
+    @Test
+    public void testPushPopAfterEmpty() {
+        sect.push(10);
+        sect.push(1);
+        sect.pop();
+        sect.pop();
+        sect.push(5);
+        assertEquals(5, sect.getMinimumElement());
+        sect.push(1);
+        assertEquals(1, sect.getMinimumElement());
+    }
+}

From 60060250caec79ee1e5f9ffa93449cfccc520b30 Mon Sep 17 00:00:00 2001
From: S M Jishanul Islam <sislam201024@bscse.uiu.ac.bd>
Date: Wed, 23 Oct 2024 01:31:29 +0600
Subject: [PATCH 0585/1338] Add palindrome checker using stack (#5887)

---
 .../stacks/PalindromeWithStack.java           | 57 ++++++++++++++
 .../stacks/PalindromeWithStackTest.java       | 77 +++++++++++++++++++
 2 files changed, 134 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/PalindromeWithStackTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java b/src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java
new file mode 100644
index 000000000000..98c439341a21
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java
@@ -0,0 +1,57 @@
+package com.thealgorithms.stacks;
+
+import java.util.LinkedList;
+
+/**
+ * A class that implements a palindrome checker using a stack.
+ * The stack is used to store the characters of the string,
+ * which we will pop one-by-one to create the string in reverse.
+ *
+ * Reference: https://www.geeksforgeeks.org/check-whether-the-given-string-is-palindrome-using-stack/
+ */
+public class PalindromeWithStack {
+    private LinkedList<Character> stack;
+
+    /**
+     * Constructs an empty stack that stores characters.
+     */
+    public PalindromeWithStack() {
+        stack = new LinkedList<Character>();
+    }
+
+    /**
+     * Check if the string is a palindrome or not.
+     * Convert all characters to lowercase and push them into a stack.
+     * At the same time, build a string
+     * Next, pop from the stack and build the reverse string
+     * Finally, compare these two strings
+     *
+     * @param string The string to check if it is palindrome or not.
+     */
+    public boolean checkPalindrome(String string) {
+        // Create a StringBuilder to build the string from left to right
+        StringBuilder stringBuilder = new StringBuilder(string.length());
+        // Convert all characters to lowercase
+        String lowercase = string.toLowerCase();
+
+        // Iterate through the string
+        for (int i = 0; i < lowercase.length(); ++i) {
+            char c = lowercase.charAt(i);
+            // Build the string from L->R
+            stringBuilder.append(c);
+            // Push to the stack
+            stack.push(c);
+        }
+
+        // The stack contains the reverse order of the string
+        StringBuilder reverseString = new StringBuilder(stack.size());
+        // Until the stack is not empty
+        while (!stack.isEmpty()) {
+            // Build the string from R->L
+            reverseString.append(stack.pop());
+        }
+
+        // Finally, compare the L->R string with the R->L string
+        return reverseString.toString().equals(stringBuilder.toString());
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/PalindromeWithStackTest.java b/src/test/java/com/thealgorithms/stacks/PalindromeWithStackTest.java
new file mode 100644
index 000000000000..47b21d5e9e9c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/PalindromeWithStackTest.java
@@ -0,0 +1,77 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class PalindromeWithStackTest {
+
+    private PalindromeWithStack palindromeChecker;
+
+    @BeforeEach
+    public void setUp() {
+        palindromeChecker = new PalindromeWithStack();
+    }
+
+    @Test
+    public void testValidOne() {
+        String testString = "Racecar";
+        assertTrue(palindromeChecker.checkPalindrome(testString));
+    }
+
+    @Test
+    public void testInvalidOne() {
+        String testString = "James";
+        assertFalse(palindromeChecker.checkPalindrome(testString));
+    }
+
+    @Test
+    public void testValidTwo() {
+        String testString = "madam";
+        assertTrue(palindromeChecker.checkPalindrome(testString));
+    }
+
+    @Test
+    public void testInvalidTwo() {
+        String testString = "pantry";
+        assertFalse(palindromeChecker.checkPalindrome(testString));
+    }
+
+    @Test
+    public void testValidThree() {
+        String testString = "RaDar";
+        assertTrue(palindromeChecker.checkPalindrome(testString));
+    }
+
+    @Test
+    public void testInvalidThree() {
+        String testString = "Win";
+        assertFalse(palindromeChecker.checkPalindrome(testString));
+    }
+
+    @Test
+    public void testBlankString() {
+        String testString = "";
+        assertTrue(palindromeChecker.checkPalindrome(testString));
+    }
+
+    @Test
+    public void testStringWithNumbers() {
+        String testString = "12321";
+        assertTrue(palindromeChecker.checkPalindrome(testString));
+    }
+
+    @Test
+    public void testStringWithNumbersTwo() {
+        String testString = "12325";
+        assertFalse(palindromeChecker.checkPalindrome(testString));
+    }
+
+    @Test
+    public void testStringWithNumbersAndLetters() {
+        String testString = "po454op";
+        assertTrue(palindromeChecker.checkPalindrome(testString));
+    }
+}

From 2f9f75a3a70a11f3321396fd4a65c7331b50574c Mon Sep 17 00:00:00 2001
From: "Vignesh.S" <128959041+coffee-loves-code-2003@users.noreply.github.com>
Date: Wed, 23 Oct 2024 11:14:02 +0530
Subject: [PATCH 0586/1338] Add StronglyConnectedComponentOptimized (#5825)

---
 .../StronglyConnectedComponentOptimized.java  | 84 +++++++++++++++++++
 ...ronglyConnectedComponentOptimizedTest.java | 78 +++++++++++++++++
 2 files changed, 162 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java
 create mode 100644 src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java

diff --git a/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java b/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java
new file mode 100644
index 000000000000..87d4e89d2c8c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java
@@ -0,0 +1,84 @@
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Stack;
+
+/**
+ * Finds the strongly connected components in a directed graph.
+ *
+ * @param adjList The adjacency list representation of the graph.
+ * @param n The number of nodes in the graph.
+ * @return The number of strongly connected components.
+ */
+public class StronglyConnectedComponentOptimized {
+
+    public void btrack(HashMap<Integer, List<Integer>> adjList, int[] visited, Stack<Integer> dfsCallsNodes, int currentNode) {
+        visited[currentNode] = 1;
+        List<Integer> neighbors = adjList.get(currentNode);
+        // Check for null before iterating
+        if (neighbors != null) {
+            for (int neighbor : neighbors) {
+                if (visited[neighbor] == -1) {
+                    btrack(adjList, visited, dfsCallsNodes, neighbor);
+                }
+            }
+        }
+        dfsCallsNodes.add(currentNode);
+    }
+
+    public void btrack2(HashMap<Integer, List<Integer>> adjRevList, int[] visited, int currentNode, List<Integer> newScc) {
+        visited[currentNode] = 1;
+        newScc.add(currentNode);
+        List<Integer> neighbors = adjRevList.get(currentNode);
+        // Check for null before iterating
+        if (neighbors != null) {
+            for (int neighbor : neighbors) {
+                if (visited[neighbor] == -1) {
+                    btrack2(adjRevList, visited, neighbor, newScc);
+                }
+            }
+        }
+    }
+
+    public int getOutput(HashMap<Integer, List<Integer>> adjList, int n) {
+        int[] visited = new int[n];
+        Arrays.fill(visited, -1);
+        Stack<Integer> dfsCallsNodes = new Stack<>();
+
+        for (int i = 0; i < n; i++) {
+            if (visited[i] == -1) {
+                btrack(adjList, visited, dfsCallsNodes, i);
+            }
+        }
+
+        HashMap<Integer, List<Integer>> adjRevList = new HashMap<>();
+        for (int i = 0; i < n; i++) {
+            adjRevList.put(i, new ArrayList<>());
+        }
+
+        for (int i = 0; i < n; i++) {
+            List<Integer> neighbors = adjList.get(i);
+            // Check for null before iterating
+            if (neighbors != null) {
+                for (int neighbor : neighbors) {
+                    adjRevList.get(neighbor).add(i);
+                }
+            }
+        }
+
+        Arrays.fill(visited, -1);
+        int stronglyConnectedComponents = 0;
+
+        while (!dfsCallsNodes.isEmpty()) {
+            int node = dfsCallsNodes.pop();
+            if (visited[node] == -1) {
+                List<Integer> newScc = new ArrayList<>();
+                btrack2(adjRevList, visited, node, newScc);
+                stronglyConnectedComponents++;
+            }
+        }
+
+        return stronglyConnectedComponents;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java b/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java
new file mode 100644
index 000000000000..6f1c8a9d53b2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java
@@ -0,0 +1,78 @@
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class StronglyConnectedComponentOptimizedTest {
+
+    private StronglyConnectedComponentOptimized sccOptimized;
+
+    @BeforeEach
+    public void setUp() {
+        sccOptimized = new StronglyConnectedComponentOptimized();
+    }
+
+    @Test
+    public void testSingleComponent() {
+        // Create a simple graph with 3 nodes, all forming one SCC
+        HashMap<Integer, List<Integer>> adjList = new HashMap<>();
+        adjList.put(0, new ArrayList<>(List.of(1)));
+        adjList.put(1, new ArrayList<>(List.of(2)));
+        adjList.put(2, new ArrayList<>(List.of(0)));
+
+        int result = sccOptimized.getOutput(adjList, 3);
+
+        // The entire graph is one strongly connected component
+        assertEquals(1, result, "There should be 1 strongly connected component.");
+    }
+
+    @Test
+    public void testTwoComponents() {
+        // Create a graph with 4 nodes and two SCCs: {0, 1, 2} and {3}
+        HashMap<Integer, List<Integer>> adjList = new HashMap<>();
+        adjList.put(0, new ArrayList<>(List.of(1)));
+        adjList.put(1, new ArrayList<>(List.of(2)));
+        adjList.put(2, new ArrayList<>(List.of(0)));
+        adjList.put(3, new ArrayList<>());
+
+        int result = sccOptimized.getOutput(adjList, 4);
+
+        // There are 2 SCCs: {0, 1, 2} and {3}
+        assertEquals(2, result, "There should be 2 strongly connected components.");
+    }
+
+    @Test
+    public void testDisconnectedGraph() {
+        // Create a graph with 4 nodes that are all disconnected
+        HashMap<Integer, List<Integer>> adjList = new HashMap<>();
+        adjList.put(0, new ArrayList<>());
+        adjList.put(1, new ArrayList<>());
+        adjList.put(2, new ArrayList<>());
+        adjList.put(3, new ArrayList<>());
+
+        int result = sccOptimized.getOutput(adjList, 4);
+
+        // Each node is its own strongly connected component
+        assertEquals(4, result, "There should be 4 strongly connected components.");
+    }
+
+    @Test
+    public void testComplexGraph() {
+        // Create a more complex graph with multiple SCCs
+        HashMap<Integer, List<Integer>> adjList = new HashMap<>();
+        adjList.put(0, new ArrayList<>(List.of(1)));
+        adjList.put(1, new ArrayList<>(List.of(2)));
+        adjList.put(2, new ArrayList<>(List.of(0, 3)));
+        adjList.put(3, new ArrayList<>(List.of(4)));
+        adjList.put(4, new ArrayList<>(List.of(5)));
+        adjList.put(5, new ArrayList<>(List.of(3)));
+
+        int result = sccOptimized.getOutput(adjList, 6);
+
+        // There are 2 SCCs: {0, 1, 2} and {3, 4, 5}
+        assertEquals(2, result, "There should be 2 strongly connected components.");
+    }
+}

From aaaf96b05f3aa87a9279d1870cc05ac04e4add86 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 11:50:58 +0530
Subject: [PATCH 0587/1338] Enhance docs, add more tests in `IntegerToEnglish`
 (#5924)

---
 DIRECTORY.md                                  | 20 ++++++
 .../conversions/IntegerToEnglish.java         | 72 +++++++++++++------
 .../conversions/IntegerToEnglishTest.java     | 31 ++++++++
 3 files changed, 101 insertions(+), 22 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 3d5b2bf61d6a..20c48ce8ca46 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -64,12 +64,15 @@
             * [AffineCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AffineCipher.java)
             * [AtbashCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java)
             * [Autokey](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Autokey.java)
+            * [BaconianCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/BaconianCipher.java)
             * [Blowfish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Blowfish.java)
             * [Caesar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Caesar.java)
             * [ColumnarTranspositionCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java)
             * [DES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/DES.java)
+            * [DiffieHellman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/DiffieHellman.java)
             * [ECC](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ECC.java)
             * [HillCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/HillCipher.java)
+            * [MonoAlphabetic](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/MonoAlphabetic.java)
             * [PlayfairCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java)
             * [Polybius](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Polybius.java)
             * [ProductCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ProductCipher.java)
@@ -311,6 +314,8 @@
             * [ConvexHull](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/ConvexHull.java)
             * [GrahamScan](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/GrahamScan.java)
             * [Point](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/Point.java)
+          * graph
+            * [StronglyConnectedComponentOptimized](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
           * greedyalgorithms
             * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
             * [BinaryAddition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java)
@@ -564,6 +569,7 @@
             * [UnionFind](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UnionFind.java)
             * [UpperBound](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UpperBound.java)
           * sorts
+            * [AdaptiveMergeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java)
             * [BeadSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BeadSort.java)
             * [BinaryInsertionSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java)
             * [BitonicSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BitonicSort.java)
@@ -603,6 +609,7 @@
             * [SortUtils](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SortUtils.java)
             * [SortUtilsRandomGenerator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java)
             * [SpreadSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SpreadSort.java)
+            * [StalinSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/StalinSort.java)
             * [StoogeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/StoogeSort.java)
             * [StrandSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/StrandSort.java)
             * [SwapSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SwapSort.java)
@@ -616,6 +623,7 @@
             * [CelebrityFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/CelebrityFinder.java)
             * [DecimalToAnyUsingStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java)
             * [DuplicateBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java)
+            * [GreatestElementConstantTime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/GreatestElementConstantTime.java)
             * [InfixToPostfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java)
             * [InfixToPrefix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java)
             * [LargestRectangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/LargestRectangle.java)
@@ -624,10 +632,12 @@
             * [MinStackUsingTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MinStackUsingTwoStacks.java)
             * [NextGreaterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java)
             * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
+            * [PalindromeWithStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java)
             * [PostfixEvaluator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java)
             * [PostfixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java)
             * [PrefixEvaluator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PrefixEvaluator.java)
             * [PrefixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PrefixToInfix.java)
+            * [SmallestElementConstantTime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/SmallestElementConstantTime.java)
             * [SortStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/SortStack.java)
             * [StackPostfixNotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
             * [StackUsingTwoQueues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackUsingTwoQueues.java)
@@ -726,12 +736,15 @@
             * [AffineCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java)
             * [AtbashTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AtbashTest.java)
             * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
+            * [BaconianCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BaconianCipherTest.java)
             * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
             * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
             * [ColumnarTranspositionCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java)
             * [DESTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DESTest.java)
+            * [DiffieHellmanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DiffieHellmanTest.java)
             * [ECCTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/ECCTest.java)
             * [HillCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/HillCipherTest.java)
+            * [MonoAlphabeticTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/MonoAlphabeticTest.java)
             * [PlayfairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java)
             * [PolybiusTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
             * [RailFenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RailFenceTest.java)
@@ -914,6 +927,8 @@
             * [BresenhamLineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java)
             * [ConvexHullTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java)
             * [GrahamScanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
+          * graph
+            * [StronglyConnectedComponentOptimizedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)
           * greedyalgorithms
             * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
             * [BinaryAdditionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java)
@@ -1133,6 +1148,7 @@
             * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java)
             * [UpperBoundTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UpperBoundTest.java)
           * sorts
+            * [AdaptiveMergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java)
             * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
             * [BinaryInsertionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java)
             * [BitonicSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java)
@@ -1171,6 +1187,7 @@
             * [SortUtilsRandomGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortUtilsRandomGeneratorTest.java)
             * [SortUtilsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java)
             * [SpreadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SpreadSortTest.java)
+            * [StalinSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StalinSortTest.java)
             * [StoogeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StoogeSortTest.java)
             * [StrandSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StrandSortTest.java)
             * [SwapSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SwapSortTest.java)
@@ -1184,6 +1201,7 @@
             * [CelebrityFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/CelebrityFinderTest.java)
             * [DecimalToAnyUsingStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/DecimalToAnyUsingStackTest.java)
             * [DuplicateBracketsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java)
+            * [GreatestElementConstantTimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/GreatestElementConstantTimeTest.java)
             * [InfixToPostfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java)
             * [InfixToPrefixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java)
             * [LargestRectangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java)
@@ -1191,10 +1209,12 @@
             * [MinStackUsingTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java)
             * [NextGreaterElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java)
             * [NextSmallerElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
+            * [PalindromeWithStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PalindromeWithStackTest.java)
             * [PostfixEvaluatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java)
             * [PostfixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java)
             * [PrefixEvaluatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java)
             * [PrefixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java)
+            * [SmallestElementConstantTimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/SmallestElementConstantTimeTest.java)
             * [SortStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/SortStackTest.java)
             * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
             * [StackUsingTwoQueuesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackUsingTwoQueuesTest.java)
diff --git a/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java b/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java
index d3b938bf492d..e85c608af5d0 100644
--- a/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java
+++ b/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java
@@ -2,7 +2,28 @@
 
 import java.util.Map;
 
+/**
+ * A utility class to convert integers to their English word representation.
+ *
+ * <p>The class supports conversion of numbers from 0 to 2,147,483,647
+ * (the maximum value of a 32-bit signed integer). It divides the number
+ * into groups of three digits (thousands, millions, billions, etc.) and
+ * translates each group into words.</p>
+ *
+ * <h2>Example Usage</h2>
+ * <pre>
+ *   IntegerToEnglish.integerToEnglishWords(12345);
+ *   // Output: "Twelve Thousand Three Hundred Forty Five"
+ * </pre>
+ *
+ * <p>This class uses two maps:</p>
+ * <ul>
+ *   <li>BASE_NUMBERS_MAP: Holds English words for numbers 0-20, multiples of 10 up to 90, and 100.</li>
+ *   <li>THOUSAND_POWER_MAP: Maps powers of 1000 (e.g., Thousand, Million, Billion).</li>
+ * </ul>
+ */
 public final class IntegerToEnglish {
+
     private static final Map<Integer, String> BASE_NUMBERS_MAP = Map.ofEntries(Map.entry(0, ""), Map.entry(1, "One"), Map.entry(2, "Two"), Map.entry(3, "Three"), Map.entry(4, "Four"), Map.entry(5, "Five"), Map.entry(6, "Six"), Map.entry(7, "Seven"), Map.entry(8, "Eight"), Map.entry(9, "Nine"),
         Map.entry(10, "Ten"), Map.entry(11, "Eleven"), Map.entry(12, "Twelve"), Map.entry(13, "Thirteen"), Map.entry(14, "Fourteen"), Map.entry(15, "Fifteen"), Map.entry(16, "Sixteen"), Map.entry(17, "Seventeen"), Map.entry(18, "Eighteen"), Map.entry(19, "Nineteen"), Map.entry(20, "Twenty"),
         Map.entry(30, "Thirty"), Map.entry(40, "Forty"), Map.entry(50, "Fifty"), Map.entry(60, "Sixty"), Map.entry(70, "Seventy"), Map.entry(80, "Eighty"), Map.entry(90, "Ninety"), Map.entry(100, "Hundred"));
@@ -13,35 +34,46 @@ private IntegerToEnglish() {
     }
 
     /**
-        converts numbers < 1000 to english words
+     * Converts numbers less than 1000 into English words.
+     *
+     * @param number the integer value (0-999) to convert
+     * @return the English word representation of the input number
      */
     private static String convertToWords(int number) {
         int remainder = number % 100;
-
-        String result;
+        StringBuilder result = new StringBuilder();
 
         if (remainder <= 20) {
-            result = BASE_NUMBERS_MAP.get(remainder);
+            result.append(BASE_NUMBERS_MAP.get(remainder));
         } else if (BASE_NUMBERS_MAP.containsKey(remainder)) {
-            result = BASE_NUMBERS_MAP.get(remainder);
+            result.append(BASE_NUMBERS_MAP.get(remainder));
         } else {
             int tensDigit = remainder / 10;
             int onesDigit = remainder % 10;
-
-            result = String.format("%s %s", BASE_NUMBERS_MAP.get(tensDigit * 10), BASE_NUMBERS_MAP.get(onesDigit));
+            String tens = BASE_NUMBERS_MAP.getOrDefault(tensDigit * 10, "");
+            String ones = BASE_NUMBERS_MAP.getOrDefault(onesDigit, "");
+            result.append(tens);
+            if (ones != null && !ones.isEmpty()) {
+                result.append(" ").append(ones);
+            }
         }
 
         int hundredsDigit = number / 100;
-
         if (hundredsDigit > 0) {
-            result = String.format("%s %s%s", BASE_NUMBERS_MAP.get(hundredsDigit), BASE_NUMBERS_MAP.get(100), result.isEmpty() ? "" : " " + result);
+            if (result.length() > 0) {
+                result.insert(0, " ");
+            }
+            result.insert(0, String.format("%s Hundred", BASE_NUMBERS_MAP.get(hundredsDigit)));
         }
 
-        return result;
+        return result.toString().trim();
     }
 
     /**
-      Only convert groups of three digit if they are non-zero
+     * Converts a non-negative integer to its English word representation.
+     *
+     * @param number the integer to convert (0-2,147,483,647)
+     * @return the English word representation of the input number
      */
     public static String integerToEnglishWords(int number) {
         if (number == 0) {
@@ -49,7 +81,6 @@ public static String integerToEnglishWords(int number) {
         }
 
         StringBuilder result = new StringBuilder();
-
         int index = 0;
 
         while (number > 0) {
@@ -58,23 +89,20 @@ public static String integerToEnglishWords(int number) {
 
             if (remainder > 0) {
                 String subResult = convertToWords(remainder);
-
                 if (!subResult.isEmpty()) {
-                    if (!result.isEmpty()) {
-                        result.insert(0, subResult + " " + THOUSAND_POWER_MAP.get(index) + " ");
-                    } else {
-                        if (index > 0) {
-                            result = new StringBuilder(subResult + " " + THOUSAND_POWER_MAP.get(index));
-                        } else {
-                            result = new StringBuilder(subResult);
-                        }
+                    if (index > 0) {
+                        subResult += " " + THOUSAND_POWER_MAP.get(index);
+                    }
+                    if (result.length() > 0) {
+                        result.insert(0, " ");
                     }
+                    result.insert(0, subResult);
                 }
             }
 
             index++;
         }
 
-        return result.toString();
+        return result.toString().trim();
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java b/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java
index 49c43402aeca..c2a94794b7f8 100644
--- a/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java
+++ b/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java
@@ -11,5 +11,36 @@ public void testIntegerToEnglish() {
         assertEquals("Two Billion One Hundred Forty Seven Million Four Hundred Eighty Three Thousand Six Hundred Forty Seven", IntegerToEnglish.integerToEnglishWords(2147483647));
         assertEquals("One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven", IntegerToEnglish.integerToEnglishWords(1234567));
         assertEquals("Twelve Thousand Three Hundred Forty Five", IntegerToEnglish.integerToEnglishWords(12345));
+        assertEquals("One Hundred", IntegerToEnglish.integerToEnglishWords(100));
+        assertEquals("Zero", IntegerToEnglish.integerToEnglishWords(0));
+    }
+
+    @Test
+    public void testSmallNumbers() {
+        assertEquals("Ten", IntegerToEnglish.integerToEnglishWords(10));
+        assertEquals("Nineteen", IntegerToEnglish.integerToEnglishWords(19));
+        assertEquals("Twenty One", IntegerToEnglish.integerToEnglishWords(21));
+        assertEquals("Ninety Nine", IntegerToEnglish.integerToEnglishWords(99));
+    }
+
+    @Test
+    public void testHundreds() {
+        assertEquals("One Hundred One", IntegerToEnglish.integerToEnglishWords(101));
+        assertEquals("Five Hundred Fifty", IntegerToEnglish.integerToEnglishWords(550));
+        assertEquals("Nine Hundred Ninety Nine", IntegerToEnglish.integerToEnglishWords(999));
+    }
+
+    @Test
+    public void testThousands() {
+        assertEquals("One Thousand", IntegerToEnglish.integerToEnglishWords(1000));
+        assertEquals("Ten Thousand One", IntegerToEnglish.integerToEnglishWords(10001));
+        assertEquals("Seventy Six Thousand Five Hundred Forty Three", IntegerToEnglish.integerToEnglishWords(76543));
+    }
+
+    @Test
+    public void testEdgeCases() {
+        assertEquals("One Million", IntegerToEnglish.integerToEnglishWords(1_000_000));
+        assertEquals("One Billion", IntegerToEnglish.integerToEnglishWords(1_000_000_000));
+        assertEquals("Two Thousand", IntegerToEnglish.integerToEnglishWords(2000));
     }
 }

From 7bbdae5fe063624484cf4e9819c52a7e0b392555 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 11:55:20 +0530
Subject: [PATCH 0588/1338] Enhance docs, add more tests in `RomanToInteger`
 (#5926)

---
 .../conversions/RomanToInteger.java           | 85 ++++++++++++-------
 .../conversions/RomanToIntegerTest.java       | 19 ++++-
 2 files changed, 73 insertions(+), 31 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
index 1934e9b264c9..a634c720326f 100644
--- a/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
+++ b/src/main/java/com/thealgorithms/conversions/RomanToInteger.java
@@ -3,9 +3,27 @@
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * A utility class to convert Roman numerals into integers.
+ *
+ * <p>Roman numerals are based on seven symbols given below:
+ * <ul>
+ *   <li>I = 1</li>
+ *   <li>V = 5</li>
+ *   <li>X = 10</li>
+ *   <li>L = 50</li>
+ *   <li>C = 100</li>
+ *   <li>D = 500</li>
+ *   <li>M = 1000</li>
+ * </ul>
+ *
+ * <p>If a smaller numeral appears before a larger numeral, it is subtracted.
+ * Otherwise, it is added. For example:
+ * <pre>
+ *   MCMXCIV = 1000 + (1000 - 100) + (100 - 10) + (5 - 1) = 1994
+ * </pre>
+ */
 public final class RomanToInteger {
-    private RomanToInteger() {
-    }
 
     private static final Map<Character, Integer> ROMAN_TO_INT = new HashMap<>() {
         {
@@ -19,44 +37,53 @@ private RomanToInteger() {
         }
     };
 
+    private RomanToInteger() {
+    }
+
+    /**
+     * Converts a single Roman numeral character to its integer value.
+     *
+     * @param symbol the Roman numeral character
+     * @return the corresponding integer value
+     * @throws IllegalArgumentException if the symbol is not a valid Roman numeral
+     */
     private static int romanSymbolToInt(final char symbol) {
         return ROMAN_TO_INT.computeIfAbsent(symbol, c -> { throw new IllegalArgumentException("Unknown Roman symbol: " + c); });
     }
 
-    // Roman Number = Roman Numerals
-
     /**
-     * This function convert Roman number into Integer
+     * Converts a Roman numeral string to its integer equivalent.
+     * Steps:
+     * <ol>
+     *     <li>Iterate over the string from right to left.</li>
+     *     <li>For each character, convert it to an integer value.</li>
+     *     <li>If the current value is greater than or equal to the max previous value, add it.</li>
+     *     <li>Otherwise, subtract it from the sum.</li>
+     *     <li>Update the max previous value.</li>
+     *     <li>Return the sum.</li>
+     * </ol>
      *
-     * @param a Roman number string
-     * @return integer
+     * @param roman the Roman numeral string
+     * @return the integer value of the Roman numeral
+     * @throws IllegalArgumentException if the input contains invalid Roman characters
+     * @throws NullPointerException if the input is {@code null}
      */
-    public static int romanToInt(String a) {
-        a = a.toUpperCase();
-        char prev = ' ';
+    public static int romanToInt(String roman) {
+        if (roman == null) {
+            throw new NullPointerException("Input cannot be null");
+        }
 
+        roman = roman.toUpperCase();
         int sum = 0;
-
-        int newPrev = 0;
-        for (int i = a.length() - 1; i >= 0; i--) {
-            char c = a.charAt(i);
-
-            if (prev != ' ') {
-                // checking current Number greater than previous or not
-                newPrev = romanSymbolToInt(prev) > newPrev ? romanSymbolToInt(prev) : newPrev;
-            }
-
-            int currentNum = romanSymbolToInt(c);
-
-            // if current number greater than prev max previous then add
-            if (currentNum >= newPrev) {
-                sum += currentNum;
+        int maxPrevValue = 0;
+        for (int i = roman.length() - 1; i >= 0; i--) {
+            int currentValue = romanSymbolToInt(roman.charAt(i));
+            if (currentValue >= maxPrevValue) {
+                sum += currentValue;
+                maxPrevValue = currentValue;
             } else {
-                // subtract upcoming number until upcoming number not greater than prev max
-                sum -= currentNum;
+                sum -= currentValue;
             }
-
-            prev = c;
         }
 
         return sum;
diff --git a/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java b/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java
index f03563971cb7..971eff8c74f5 100644
--- a/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java
+++ b/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java
@@ -8,16 +8,31 @@
 public class RomanToIntegerTest {
 
     @Test
-    public void testRomanToInteger() {
+    public void testValidRomanToInteger() {
         assertEquals(1994, RomanToInteger.romanToInt("MCMXCIV"));
         assertEquals(58, RomanToInteger.romanToInt("LVIII"));
         assertEquals(1804, RomanToInteger.romanToInt("MDCCCIV"));
+        assertEquals(9, RomanToInteger.romanToInt("IX"));
+        assertEquals(4, RomanToInteger.romanToInt("IV"));
+        assertEquals(3000, RomanToInteger.romanToInt("MMM"));
     }
 
     @Test
-    void testRomanToIntegerThrows() {
+    public void testLowercaseInput() {
+        assertEquals(1994, RomanToInteger.romanToInt("mcmxciv"));
+        assertEquals(58, RomanToInteger.romanToInt("lviii"));
+    }
+
+    @Test
+    public void testInvalidRomanNumerals() {
         assertThrows(IllegalArgumentException.class, () -> RomanToInteger.romanToInt("Z"));
         assertThrows(IllegalArgumentException.class, () -> RomanToInteger.romanToInt("MZI"));
         assertThrows(IllegalArgumentException.class, () -> RomanToInteger.romanToInt("MMMO"));
     }
+
+    @Test
+    public void testEmptyAndNullInput() {
+        assertEquals(0, RomanToInteger.romanToInt("")); // Empty string case
+        assertThrows(NullPointerException.class, () -> RomanToInteger.romanToInt(null)); // Null input case
+    }
 }

From d85f192421bbbc0728aaec476b84974942588a10 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 12:03:00 +0530
Subject: [PATCH 0589/1338] Enhance docs, add more tests in `OctalToBinary`
 (#5942)

---
 .../conversions/OctalToBinary.java            | 45 +++++++++++++++++--
 .../conversions/OctalToBinaryTest.java        | 20 +++++++++
 2 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/OctalToBinary.java b/src/main/java/com/thealgorithms/conversions/OctalToBinary.java
index 6b01c2f65cfe..a66db97633b4 100644
--- a/src/main/java/com/thealgorithms/conversions/OctalToBinary.java
+++ b/src/main/java/com/thealgorithms/conversions/OctalToBinary.java
@@ -1,14 +1,40 @@
 package com.thealgorithms.conversions;
 
 /**
- * Converts any Octal Number to a Binary Number
+ * A utility class to convert an octal (base-8) number into its binary (base-2) representation.
+ *
+ * <p>This class provides methods to:
+ * <ul>
+ *     <li>Convert an octal number to its binary equivalent</li>
+ *     <li>Convert individual octal digits to binary</li>
+ * </ul>
+ *
+ * <h2>Octal to Binary Conversion:</h2>
+ * <p>An octal number is converted to binary by converting each octal digit to its 3-bit binary equivalent.
+ * The result is a long representing the full binary equivalent of the octal number.</p>
+ *
+ * <h2>Example Usage</h2>
+ * <pre>
+ *   long binary = OctalToBinary.convertOctalToBinary(52); // Output: 101010 (52 in octal is 101010 in binary)
+ * </pre>
  *
  * @author Bama Charan Chhandogi
+ * @see <a href="https://en.wikipedia.org/wiki/Octal">Octal Number System</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Binary_number">Binary Number System</a>
  */
-
 public final class OctalToBinary {
     private OctalToBinary() {
     }
+
+    /**
+     * Converts an octal number to its binary representation.
+     *
+     * <p>Each octal digit is individually converted to its 3-bit binary equivalent, and the binary
+     * digits are concatenated to form the final binary number.</p>
+     *
+     * @param octalNumber the octal number to convert (non-negative integer)
+     * @return the binary equivalent as a long
+     */
     public static long convertOctalToBinary(int octalNumber) {
         long binaryNumber = 0;
         int digitPosition = 1;
@@ -20,12 +46,25 @@ public static long convertOctalToBinary(int octalNumber) {
             binaryNumber += binaryDigit * digitPosition;
 
             octalNumber /= 10;
-            digitPosition *= 1000; // Move to the next group of 3 binary digits
+            digitPosition *= 1000;
         }
 
         return binaryNumber;
     }
 
+    /**
+     * Converts a single octal digit (0-7) to its binary equivalent.
+     *
+     * <p>For example:
+     * <ul>
+     *     <li>Octal digit 7 is converted to binary 111</li>
+     *     <li>Octal digit 3 is converted to binary 011</li>
+     * </ul>
+     * </p>
+     *
+     * @param octalDigit a single octal digit (0-7)
+     * @return the binary equivalent as a long
+     */
     public static long convertOctalDigitToBinary(int octalDigit) {
         long binaryDigit = 0;
         int binaryMultiplier = 1;
diff --git a/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java b/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java
index 86cf692c5258..8e007151c301 100644
--- a/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java
+++ b/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java
@@ -12,4 +12,24 @@ public void testConvertOctalToBinary() {
         assertEquals(101010, OctalToBinary.convertOctalToBinary(52));
         assertEquals(110, OctalToBinary.convertOctalToBinary(6));
     }
+
+    @Test
+    public void testConvertOctalToBinarySingleDigit() {
+        assertEquals(0, OctalToBinary.convertOctalToBinary(0));
+        assertEquals(1, OctalToBinary.convertOctalToBinary(1));
+        assertEquals(111, OctalToBinary.convertOctalToBinary(7));
+    }
+
+    @Test
+    public void testConvertOctalToBinaryMultipleDigits() {
+        assertEquals(100110111, OctalToBinary.convertOctalToBinary(467));
+        assertEquals(111101, OctalToBinary.convertOctalToBinary(75));
+        assertEquals(111100101, OctalToBinary.convertOctalToBinary(745));
+    }
+
+    @Test
+    public void testConvertOctalToBinaryWithZeroPadding() {
+        assertEquals(100001010, OctalToBinary.convertOctalToBinary(412));
+        assertEquals(101101110, OctalToBinary.convertOctalToBinary(556));
+    }
 }

From 757d10c277b8148cd44ada53dc49c9ab37fd5d79 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 12:06:43 +0530
Subject: [PATCH 0590/1338] Remove 'main', add tests in
 `TurkishToLatinConversion` (#5944)

---
 DIRECTORY.md                                  |  1 +
 .../conversions/TurkishToLatinConversion.java | 19 +++---------
 .../TurkishToLatinConversionTest.java         | 31 +++++++++++++++++++
 3 files changed, 36 insertions(+), 15 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 20c48ce8ca46..4f4276860928 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -775,6 +775,7 @@
             * [OctalToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
             * [PhoneticAlphabetConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java)
             * [RomanToIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java)
+            * [TurkishToLatinConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java)
             * [UnitConversionsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java)
             * [UnitsConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java)
           * datastructures
diff --git a/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java b/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
index 4d13b8b7fd55..30030de6c1bd 100644
--- a/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
+++ b/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.conversions;
 
-import java.util.Scanner;
-
 /**
  * Converts turkish character to latin character
  *
@@ -11,21 +9,12 @@ public final class TurkishToLatinConversion {
     private TurkishToLatinConversion() {
     }
 
-    /**
-     * Main method
-     *
-     * @param args Command line arguments
-     */
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        System.out.println("Input the string: ");
-        String b = sc.next();
-        System.out.println("Converted: " + convertTurkishToLatin(b));
-        sc.close();
-    }
-
     /**
      * This method converts a turkish character to latin character.
+     * Steps:
+     * 1. Define turkish characters and their corresponding latin characters
+     * 2. Replace all turkish characters with their corresponding latin characters
+     * 3. Return the converted string
      *
      * @param param String paramter
      * @return String
diff --git a/src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java b/src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java
new file mode 100644
index 000000000000..87e40c78e6a2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java
@@ -0,0 +1,31 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class TurkishToLatinConversionTest {
+
+    @ParameterizedTest
+    @CsvSource({
+        "'çalışma', 'calisma'", // Turkish to Latin conversion for lowercase
+        "'ÇALIŞMA', 'CALISMA'", // Turkish to Latin conversion for uppercase
+        "'İSTANBUL', 'ISTANBUL'", // Special case of 'İ' to 'I'
+        "'istanbul', 'istanbul'", // Special case of 'ı' to 'i'
+        "'GÜL', 'GUL'", // Special case of 'Ü' to 'U'
+        "'gül', 'gul'", // Special case of 'ü' to 'u'
+        "'ÖĞRENME', 'OGRENME'", // Special case of 'Ö' to 'O' and 'Ğ' to 'G'
+        "'öğrenme', 'ogrenme'", // Special case of 'ö' to 'o' and 'ğ' to 'g'
+        "'ŞEHIR', 'SEHIR'", // Special case of 'Ş' to 'S'
+        "'şehir', 'sehir'", // Special case of 'ş' to 's'
+        "'HELLO', 'HELLO'", // String with no Turkish characters, should remain unchanged
+        "'Merhaba Dünya!', 'Merhaba Dunya!'", // Mixed Turkish and Latin characters with punctuation
+        "'Çift kişilik yataklı odalar', 'Cift kisilik yatakli odalar'", // Full sentence conversion
+        "'', ''" // Empty string case
+    })
+    public void
+    testConvertTurkishToLatin(String input, String expectedOutput) {
+        assertEquals(expectedOutput, TurkishToLatinConversion.convertTurkishToLatin(input));
+    }
+}

From 03fe106e328aecc629e8c8174fff02f126d7a8e9 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 12:11:48 +0530
Subject: [PATCH 0591/1338] Enhance docs, add more tests in
 `PhoneticAlphabetConverter` (#5943)

---
 .../PhoneticAlphabetConverter.java            | 16 ++++++++++
 .../PhoneticAlphabetConverterTest.java        | 30 +++++++++++--------
 2 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java b/src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java
index bcea1862e99e..730ce2214e2d 100644
--- a/src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java
+++ b/src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java
@@ -58,9 +58,25 @@ private PhoneticAlphabetConverter() {
         PHONETIC_MAP.put('9', "Nine");
     }
 
+    /**
+     * Converts text to the NATO phonetic alphabet.
+     * Steps:
+     * 1. Convert the text to uppercase.
+     * 2. Iterate over each character in the text.
+     * 3. Get the phonetic equivalent of the character from the map.
+     * 4. Append the phonetic equivalent to the result.
+     * 5. Append a space to separate the phonetic equivalents.
+     * 6. Return the result.
+     *
+     * @param text the text to convert
+     * @return the NATO phonetic alphabet
+     */
     public static String textToPhonetic(String text) {
         StringBuilder phonetic = new StringBuilder();
         for (char c : text.toUpperCase().toCharArray()) {
+            if (Character.isWhitespace(c)) {
+                continue;
+            }
             phonetic.append(PHONETIC_MAP.getOrDefault(c, String.valueOf(c))).append(" ");
         }
         return phonetic.toString().trim();
diff --git a/src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java b/src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java
index 07847302c8d8..360af7fa0f51 100644
--- a/src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java
+++ b/src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java
@@ -2,20 +2,26 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class PhoneticAlphabetConverterTest {
 
-    @Test
-    public void testTextToPhonetic() {
-        assertEquals("Alpha Bravo", PhoneticAlphabetConverter.textToPhonetic("AB"));
-        assertEquals("Alpha Bravo Charlie", PhoneticAlphabetConverter.textToPhonetic("ABC"));
-        assertEquals("Alpha One Bravo Two Charlie Three", PhoneticAlphabetConverter.textToPhonetic("A1B2C3"));
-        assertEquals("Hotel Echo Lima Lima Oscar", PhoneticAlphabetConverter.textToPhonetic("Hello"));
-        assertEquals("One Two Three", PhoneticAlphabetConverter.textToPhonetic("123"));
-        assertEquals("Alpha Bravo Charlie Delta Echo Foxtrot Golf Hotel India Juliett Kilo Lima Mike November Oscar Papa Quebec Romeo Sierra Tango Uniform Victor Whiskey X-ray Yankee Zulu Zero One Two Three Four Five Six Seven Eight Nine",
-            PhoneticAlphabetConverter.textToPhonetic("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"));
-        assertEquals("Alpha Bravo Charlie Delta Echo Foxtrot Golf Hotel India Juliett Kilo Lima Mike November Oscar Papa Quebec Romeo Sierra Tango Uniform Victor Whiskey X-ray Yankee Zulu Zero One Two Three Four Five Six Seven Eight Nine",
-            PhoneticAlphabetConverter.textToPhonetic("abcdefghijklmnopqrstuvwxyz0123456789"));
+    @ParameterizedTest
+    @CsvSource({
+        "'AB', 'Alpha Bravo'", "'ABC', 'Alpha Bravo Charlie'", "'A1B2C3', 'Alpha One Bravo Two Charlie Three'", "'Hello', 'Hotel Echo Lima Lima Oscar'", "'123', 'One Two Three'",
+        "'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789', 'Alpha Bravo Charlie Delta Echo Foxtrot Golf Hotel India Juliett Kilo Lima Mike November Oscar Papa Quebec Romeo Sierra Tango Uniform Victor Whiskey X-ray Yankee Zulu Zero One Two Three Four Five Six Seven Eight Nine'",
+        "'abcdefghijklmnopqrstuvwxyz0123456789', 'Alpha Bravo Charlie Delta Echo Foxtrot Golf Hotel India Juliett Kilo Lima Mike November Oscar Papa Quebec Romeo Sierra Tango Uniform Victor Whiskey X-ray Yankee Zulu Zero One Two Three Four Five Six Seven Eight Nine'",
+        "'', ''", // Empty string case
+        "'A B C', 'Alpha Bravo Charlie'", // String with spaces
+        "'A@B#C', 'Alpha @ Bravo # Charlie'", // Special characters
+        "'A B C 123', 'Alpha Bravo Charlie One Two Three'", // Mixed letters, digits, and spaces
+        "'a b c', 'Alpha Bravo Charlie'", // Lowercase letters with spaces
+        "'123!@#', 'One Two Three ! @ #'", // Numbers with special characters
+        "'HELLO WORLD', 'Hotel Echo Lima Lima Oscar Whiskey Oscar Romeo Lima Delta'" // Words with space
+    })
+    public void
+    testTextToPhonetic(String input, String expectedOutput) {
+        assertEquals(expectedOutput, PhoneticAlphabetConverter.textToPhonetic(input));
     }
 }

From a8a1abac643f763f058ce430f4c93946583f635b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 12:17:59 +0530
Subject: [PATCH 0592/1338] Enhance docs in `UnitConversions` (#5945)

---
 .../conversions/UnitConversions.java          | 37 +++++++++++++++++++
 .../conversions/UnitConversionsTest.java      |  4 +-
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/UnitConversions.java b/src/main/java/com/thealgorithms/conversions/UnitConversions.java
index abc06a0f8863..15f74a21a17e 100644
--- a/src/main/java/com/thealgorithms/conversions/UnitConversions.java
+++ b/src/main/java/com/thealgorithms/conversions/UnitConversions.java
@@ -5,10 +5,47 @@
 import java.util.Map;
 import org.apache.commons.lang3.tuple.Pair;
 
+/**
+ * A utility class to perform unit conversions between different measurement systems.
+ *
+ * <p>Currently, the class supports temperature conversions between several scales:
+ * Celsius, Fahrenheit, Kelvin, Réaumur, Delisle, and Rankine.
+ *
+ * <h2>Example Usage</h2>
+ * <pre>
+ *   double result = UnitConversions.TEMPERATURE.convert("Celsius", "Fahrenheit", 100.0);
+ *   // Output: 212.0 (Celsius to Fahrenheit conversion of 100°C)
+ * </pre>
+ *
+ * <p>This class makes use of an {@link UnitsConverter} that handles the conversion logic
+ * based on predefined affine transformations. These transformations include scaling factors
+ * and offsets for temperature conversions.
+ *
+ * <h2>Temperature Scales Supported</h2>
+ * <ul>
+ *   <li>Celsius</li>
+ *   <li>Fahrenheit</li>
+ *   <li>Kelvin</li>
+ *   <li>Réaumur</li>
+ *   <li>Delisle</li>
+ *   <li>Rankine</li>
+ * </ul>
+ */
 public final class UnitConversions {
     private UnitConversions() {
     }
 
+    /**
+     * A preconfigured instance of {@link UnitsConverter} for temperature conversions.
+     * The converter handles conversions between the following temperature units:
+     * <ul>
+     *   <li>Kelvin to Celsius</li>
+     *   <li>Celsius to Fahrenheit</li>
+     *   <li>Réaumur to Celsius</li>
+     *   <li>Delisle to Celsius</li>
+     *   <li>Rankine to Kelvin</li>
+     * </ul>
+     */
     public static final UnitsConverter TEMPERATURE = new UnitsConverter(Map.ofEntries(entry(Pair.of("Kelvin", "Celsius"), new AffineConverter(1.0, -273.15)), entry(Pair.of("Celsius", "Fahrenheit"), new AffineConverter(9.0 / 5.0, 32.0)),
         entry(Pair.of("Réaumur", "Celsius"), new AffineConverter(5.0 / 4.0, 0.0)), entry(Pair.of("Delisle", "Celsius"), new AffineConverter(-2.0 / 3.0, 100.0)), entry(Pair.of("Rankine", "Kelvin"), new AffineConverter(5.0 / 9.0, 0.0))));
 }
diff --git a/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java b/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java
index 073e7d6de2c6..3c4e3d5e4c54 100644
--- a/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java
+++ b/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java
@@ -13,8 +13,8 @@
 
 public class UnitConversionsTest {
     private static void addData(Stream.Builder<Arguments> builder, Map<String, Double> values) {
-        for (final var first : values.entrySet()) {
-            for (final var second : values.entrySet()) {
+        for (var first : values.entrySet()) {
+            for (var second : values.entrySet()) {
                 if (!first.getKey().equals(second.getKey())) {
                     builder.add(Arguments.of(first.getKey(), second.getKey(), first.getValue(), second.getValue()));
                 }

From fef1f3ca44247f62ec1530cd8d2b2d44872fc757 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 12:25:23 +0530
Subject: [PATCH 0593/1338] Enhance docs, add more tests in `UnitsConverter`
 (#5946)

---
 .../conversions/UnitsConverter.java           | 60 +++++++++++++++++++
 .../conversions/UnitsConverterTest.java       | 17 ++++++
 2 files changed, 77 insertions(+)

diff --git a/src/main/java/com/thealgorithms/conversions/UnitsConverter.java b/src/main/java/com/thealgorithms/conversions/UnitsConverter.java
index 81c4d4562070..00690b2c0f9b 100644
--- a/src/main/java/com/thealgorithms/conversions/UnitsConverter.java
+++ b/src/main/java/com/thealgorithms/conversions/UnitsConverter.java
@@ -7,6 +7,43 @@
 import java.util.Set;
 import org.apache.commons.lang3.tuple.Pair;
 
+/**
+ * A class that handles unit conversions using affine transformations.
+ *
+ * <p>The {@code UnitsConverter} allows converting values between different units using
+ * pre-defined affine conversion formulas. Each conversion is represented by an
+ * {@link AffineConverter} that defines the scaling and offset for the conversion.
+ *
+ * <p>For each unit, both direct conversions (e.g., Celsius to Fahrenheit) and inverse
+ * conversions (e.g., Fahrenheit to Celsius) are generated automatically. It also computes
+ * transitive conversions (e.g., Celsius to Kelvin via Fahrenheit if both conversions exist).
+ *
+ * <p>Key features include:
+ * <ul>
+ *   <li>Automatic handling of inverse conversions (e.g., Fahrenheit to Celsius).</li>
+ *   <li>Compositional conversions, meaning if conversions between A -> B and B -> C exist,
+ *       it can automatically generate A -> C conversion.</li>
+ *   <li>Supports multiple unit systems as long as conversions are provided in pairs.</li>
+ * </ul>
+ *
+ * <h2>Example Usage</h2>
+ * <pre>
+ * Map&lt;Pair&lt;String, String&gt;, AffineConverter&gt; basicConversions = Map.ofEntries(
+ *     entry(Pair.of("Celsius", "Fahrenheit"), new AffineConverter(9.0 / 5.0, 32.0)),
+ *     entry(Pair.of("Kelvin", "Celsius"), new AffineConverter(1.0, -273.15))
+ * );
+ *
+ * UnitsConverter converter = new UnitsConverter(basicConversions);
+ * double result = converter.convert("Celsius", "Fahrenheit", 100.0);
+ * // Output: 212.0 (Celsius to Fahrenheit conversion of 100°C)
+ * </pre>
+ *
+ * <h2>Exception Handling</h2>
+ * <ul>
+ *   <li>If the input unit and output unit are the same, an {@link IllegalArgumentException} is thrown.</li>
+ *   <li>If a conversion between the requested units does not exist, a {@link NoSuchElementException} is thrown.</li>
+ * </ul>
+ */
 public final class UnitsConverter {
     private final Map<Pair<String, String>, AffineConverter> conversions;
     private final Set<String> units;
@@ -68,11 +105,29 @@ private static Set<String> extractUnits(final Map<Pair<String, String>, AffineCo
         return res;
     }
 
+    /**
+     * Constructor for {@code UnitsConverter}.
+     *
+     * <p>Accepts a map of basic conversions and automatically generates inverse and
+     * transitive conversions.
+     *
+     * @param basicConversions the initial set of unit conversions to add.
+     */
     public UnitsConverter(final Map<Pair<String, String>, AffineConverter> basicConversions) {
         conversions = computeAllConversions(basicConversions);
         units = extractUnits(conversions);
     }
 
+    /**
+     * Converts a value from one unit to another.
+     *
+     * @param inputUnit the unit of the input value.
+     * @param outputUnit the unit to convert the value into.
+     * @param value the value to convert.
+     * @return the converted value in the target unit.
+     * @throws IllegalArgumentException if inputUnit equals outputUnit.
+     * @throws NoSuchElementException if no conversion exists between the units.
+     */
     public double convert(final String inputUnit, final String outputUnit, final double value) {
         if (inputUnit.equals(outputUnit)) {
             throw new IllegalArgumentException("inputUnit must be different from outputUnit.");
@@ -81,6 +136,11 @@ public double convert(final String inputUnit, final String outputUnit, final dou
         return conversions.computeIfAbsent(conversionKey, k -> { throw new NoSuchElementException("No converter for: " + k); }).convert(value);
     }
 
+    /**
+     * Retrieves the set of all units supported by this converter.
+     *
+     * @return a set of available units.
+     */
     public Set<String> availableUnits() {
         return units;
     }
diff --git a/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java b/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java
index 580a66bc01ec..0952129efb4d 100644
--- a/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java
+++ b/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java
@@ -1,10 +1,12 @@
 package com.thealgorithms.conversions;
 
 import static java.util.Map.entry;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.Map;
 import java.util.NoSuchElementException;
+import java.util.Set;
 import org.apache.commons.lang3.tuple.Pair;
 import org.junit.jupiter.api.Test;
 
@@ -24,4 +26,19 @@ void testConvertThrowsForUnknownUnits() {
         assertThrows(NoSuchElementException.class, () -> someConverter.convert("X", "A", 20.0));
         assertThrows(NoSuchElementException.class, () -> someConverter.convert("X", "Y", 20.0));
     }
+
+    @Test
+    void testAvailableUnits() {
+        final UnitsConverter someConverter = new UnitsConverter(Map.ofEntries(entry(Pair.of("Celsius", "Fahrenheit"), new AffineConverter(9.0 / 5.0, 32.0)), entry(Pair.of("Kelvin", "Celsius"), new AffineConverter(1.0, -273.15))));
+        assertEquals(Set.of("Celsius", "Fahrenheit", "Kelvin"), someConverter.availableUnits());
+    }
+
+    @Test
+    void testInvertConversion() {
+        final UnitsConverter someConverter = new UnitsConverter(Map.ofEntries(entry(Pair.of("A", "B"), new AffineConverter(2.0, 5.0))));
+        // Check conversion from A -> B
+        assertEquals(25.0, someConverter.convert("A", "B", 10.0), 0.0001);
+        // Check inverse conversion from B -> A
+        assertEquals(10.0, someConverter.convert("B", "A", 25.0), 0.0001);
+    }
 }

From 730eb5a5f699f70dd56d2e61b047f560b62e24e1 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 12:31:26 +0530
Subject: [PATCH 0594/1338] Enhance docs, add more tests in `Bag` (#5947)

---
 .../datastructures/bags/Bag.java              | 46 ++++++++++++---
 .../datastructures/bag/BagTest.java           | 56 +++++++++++++++++--
 2 files changed, 89 insertions(+), 13 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/bags/Bag.java b/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
index 1bb143fabda1..afc3bbe40cce 100644
--- a/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
+++ b/src/main/java/com/thealgorithms/datastructures/bags/Bag.java
@@ -4,14 +4,18 @@
 import java.util.NoSuchElementException;
 
 /**
- * A collection that allows adding and iterating over elements but does not support element removal.
+ * A generic collection that allows adding and iterating over elements but does not support
+ * element removal. This class implements a simple bag data structure, which can hold duplicate
+ * elements and provides operations to check for membership and the size of the collection.
+ *
+ * <p>Bag is not thread-safe and should not be accessed by multiple threads concurrently.
  *
  * @param <E> the type of elements in this bag
  */
 public class Bag<E> implements Iterable<E> {
 
-    private Node<E> firstElement; // First element in the bag
-    private int size; // Number of elements in the bag
+    private Node<E> firstElement; // Reference to the first element in the bag
+    private int size; // Count of elements in the bag
 
     // Node class representing each element in the bag
     private static final class Node<E> {
@@ -21,6 +25,7 @@ private static final class Node<E> {
 
     /**
      * Constructs an empty bag.
+     * <p>This initializes the bag with zero elements.
      */
     public Bag() {
         firstElement = null;
@@ -30,7 +35,7 @@ public Bag() {
     /**
      * Checks if the bag is empty.
      *
-     * @return true if the bag is empty, false otherwise
+     * @return {@code true} if the bag contains no elements; {@code false} otherwise
      */
     public boolean isEmpty() {
         return size == 0;
@@ -39,7 +44,7 @@ public boolean isEmpty() {
     /**
      * Returns the number of elements in the bag.
      *
-     * @return the number of elements
+     * @return the number of elements currently in the bag
      */
     public int size() {
         return size;
@@ -48,7 +53,10 @@ public int size() {
     /**
      * Adds an element to the bag.
      *
-     * @param element the element to add
+     * <p>This method adds the specified element to the bag. Duplicates are allowed, and the
+     * bag will maintain the order in which elements are added.
+     *
+     * @param element the element to add; must not be {@code null}
      */
     public void add(E element) {
         Node<E> newNode = new Node<>();
@@ -61,8 +69,10 @@ public void add(E element) {
     /**
      * Checks if the bag contains a specific element.
      *
-     * @param element the element to check for
-     * @return true if the bag contains the element, false otherwise
+     * <p>This method uses the {@code equals} method of the element to determine membership.
+     *
+     * @param element the element to check for; must not be {@code null}
+     * @return {@code true} if the bag contains the specified element; {@code false} otherwise
      */
     public boolean contains(E element) {
         for (E value : this) {
@@ -76,6 +86,8 @@ public boolean contains(E element) {
     /**
      * Returns an iterator over the elements in this bag.
      *
+     * <p>The iterator provides a way to traverse the elements in the order they were added.
+     *
      * @return an iterator that iterates over the elements in the bag
      */
     @Override
@@ -88,19 +100,35 @@ private static class ListIterator<E> implements Iterator<E> {
 
         private Node<E> currentElement;
 
+        /**
+         * Constructs a ListIterator starting from the given first element.
+         *
+         * @param firstElement the first element of the bag to iterate over
+         */
         ListIterator(Node<E> firstElement) {
             this.currentElement = firstElement;
         }
 
+        /**
+         * Checks if there are more elements to iterate over.
+         *
+         * @return {@code true} if there are more elements; {@code false} otherwise
+         */
         @Override
         public boolean hasNext() {
             return currentElement != null;
         }
 
+        /**
+         * Returns the next element in the iteration.
+         *
+         * @return the next element in the bag
+         * @throws NoSuchElementException if there are no more elements to return
+         */
         @Override
         public E next() {
             if (!hasNext()) {
-                throw new NoSuchElementException();
+                throw new NoSuchElementException("No more elements in the bag.");
             }
             E element = currentElement.content;
             currentElement = currentElement.nextElement;
diff --git a/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java b/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
index c0fe107bfba5..b7e64851383c 100644
--- a/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.datastructures.bags.Bag;
@@ -68,12 +69,12 @@ void testContainsMethod() {
     }
 
     @Test
-    void testContainsAfterRemoveOperation() {
+    void testContainsAfterAdditions() {
         Bag<String> bag = new Bag<>();
         bag.add("item1");
         bag.add("item2");
-        assertTrue(bag.contains("item1"), "Bag should contain 'item1' before removal");
-        assertTrue(bag.contains("item2"), "Bag should contain 'item2' before removal");
+        assertTrue(bag.contains("item1"), "Bag should contain 'item1' after addition");
+        assertTrue(bag.contains("item2"), "Bag should contain 'item2' after addition");
     }
 
     @Test
@@ -106,6 +107,53 @@ void testRemoveMethodThrowsException() {
         Bag<String> bag = new Bag<>();
         bag.add("item1");
         Iterator<String> iterator = bag.iterator();
-        org.junit.jupiter.api.Assertions.assertThrows(UnsupportedOperationException.class, iterator::remove, "Remove operation should throw UnsupportedOperationException");
+        assertThrows(UnsupportedOperationException.class, iterator::remove, "Remove operation should throw UnsupportedOperationException");
+    }
+
+    @Test
+    void testMultipleDuplicates() {
+        Bag<String> bag = new Bag<>();
+        bag.add("item1");
+        bag.add("item1");
+        bag.add("item1"); // Add three duplicates
+
+        assertEquals(3, bag.size(), "Bag size should be 3 after adding three duplicates");
+        assertTrue(bag.contains("item1"), "Bag should contain 'item1'");
+    }
+
+    @Test
+    void testLargeNumberOfElements() {
+        Bag<Integer> bag = new Bag<>();
+        for (int i = 0; i < 1000; i++) {
+            bag.add(i);
+        }
+        assertEquals(1000, bag.size(), "Bag should contain 1000 elements");
+    }
+
+    @Test
+    void testMixedTypeElements() {
+        Bag<Object> bag = new Bag<>();
+        bag.add("string");
+        bag.add(1);
+        bag.add(2.0);
+
+        assertTrue(bag.contains("string"), "Bag should contain a string");
+        assertTrue(bag.contains(1), "Bag should contain an integer");
+        assertTrue(bag.contains(2.0), "Bag should contain a double");
+    }
+
+    @Test
+    void testIteratorWithDuplicates() {
+        Bag<String> bag = new Bag<>();
+        bag.add("item1");
+        bag.add("item1");
+        bag.add("item2");
+
+        int count = 0;
+        for (String item : bag) {
+            assertTrue(item.equals("item1") || item.equals("item2"), "Item should be either 'item1' or 'item2'");
+            count++;
+        }
+        assertEquals(3, count, "Iterator should traverse all 3 items including duplicates");
     }
 }

From 8db9d107481e2ff799b7636f08d30818c9db281a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 12:37:14 +0530
Subject: [PATCH 0595/1338] Enhance docs, add more tests in `BloomFilter`
 (#5948)

---
 .../bloomfilter/BloomFilter.java              | 43 +++++++++++++---
 .../bloomfilter/BloomFilterTest.java          | 51 +++++++++++++++++++
 2 files changed, 87 insertions(+), 7 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
index 33ea22c3d271..a2edd3db2d8e 100644
--- a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
+++ b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
@@ -4,6 +4,11 @@
 
 /**
  * A generic BloomFilter implementation for probabilistic membership checking.
+ * <p>
+ * Bloom filters are space-efficient data structures that provide a fast way to test whether an
+ * element is a member of a set. They may produce false positives, indicating an element is
+ * in the set when it is not, but they will never produce false negatives.
+ * </p>
  *
  * @param <T> The type of elements to be stored in the Bloom filter.
  */
@@ -17,10 +22,14 @@ public class BloomFilter<T> {
      * Constructs a BloomFilter with a specified number of hash functions and bit array size.
      *
      * @param numberOfHashFunctions the number of hash functions to use
-     * @param bitArraySize          the size of the bit array
+     * @param bitArraySize          the size of the bit array, which determines the capacity of the filter
+     * @throws IllegalArgumentException if numberOfHashFunctions or bitArraySize is less than 1
      */
     @SuppressWarnings("unchecked")
     public BloomFilter(int numberOfHashFunctions, int bitArraySize) {
+        if (numberOfHashFunctions < 1 || bitArraySize < 1) {
+            throw new IllegalArgumentException("Number of hash functions and bit array size must be greater than 0");
+        }
         this.numberOfHashFunctions = numberOfHashFunctions;
         this.bitArray = new BitSet(bitArraySize);
         this.hashFunctions = new Hash[numberOfHashFunctions];
@@ -28,7 +37,7 @@ public BloomFilter(int numberOfHashFunctions, int bitArraySize) {
     }
 
     /**
-     * Initializes the hash functions with unique indices.
+     * Initializes the hash functions with unique indices to ensure different hashing.
      */
     private void initializeHashFunctions() {
         for (int i = 0; i < numberOfHashFunctions; i++) {
@@ -38,8 +47,12 @@ private void initializeHashFunctions() {
 
     /**
      * Inserts an element into the Bloom filter.
+     * <p>
+     * This method hashes the element using all defined hash functions and sets the corresponding
+     * bits in the bit array.
+     * </p>
      *
-     * @param key the element to insert
+     * @param key the element to insert into the Bloom filter
      */
     public void insert(T key) {
         for (Hash<T> hash : hashFunctions) {
@@ -50,8 +63,13 @@ public void insert(T key) {
 
     /**
      * Checks if an element might be in the Bloom filter.
+     * <p>
+     * This method checks the bits at the positions computed by each hash function. If any of these
+     * bits are not set, the element is definitely not in the filter. If all bits are set, the element
+     * might be in the filter.
+     * </p>
      *
-     * @param key the element to check
+     * @param key the element to check for membership in the Bloom filter
      * @return {@code true} if the element might be in the Bloom filter, {@code false} if it is definitely not
      */
     public boolean contains(T key) {
@@ -66,6 +84,9 @@ public boolean contains(T key) {
 
     /**
      * Inner class representing a hash function used by the Bloom filter.
+     * <p>
+     * Each instance of this class represents a different hash function based on its index.
+     * </p>
      *
      * @param <T> The type of elements to be hashed.
      */
@@ -76,7 +97,7 @@ private static class Hash<T> {
         /**
          * Constructs a Hash function with a specified index.
          *
-         * @param index the index of this hash function
+         * @param index the index of this hash function, used to create a unique hash
          */
         Hash(int index) {
             this.index = index;
@@ -84,9 +105,13 @@ private static class Hash<T> {
 
         /**
          * Computes the hash of the given key.
+         * <p>
+         * The hash value is calculated by multiplying the index of the hash function
+         * with the ASCII sum of the string representation of the key.
+         * </p>
          *
          * @param key the element to hash
-         * @return the hash value
+         * @return the computed hash value
          */
         public int compute(T key) {
             return index * asciiString(String.valueOf(key));
@@ -94,9 +119,13 @@ public int compute(T key) {
 
         /**
          * Computes the ASCII value sum of the characters in a string.
+         * <p>
+         * This method iterates through each character of the string and accumulates
+         * their ASCII values to produce a single integer value.
+         * </p>
          *
          * @param word the string to compute
-         * @return the sum of ASCII values of the characters
+         * @return the sum of ASCII values of the characters in the string
          */
         private int asciiString(String word) {
             int sum = 0;
diff --git a/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java b/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java
index b19801a5ad71..048eb7e481a7 100644
--- a/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java
@@ -62,4 +62,55 @@ void testMultipleInsertions() {
 
         Assertions.assertFalse(bloomFilter.contains("key" + 200));
     }
+
+    @Test
+    void testEmptyFilterContains() {
+        Assertions.assertFalse(bloomFilter.contains("notInserted"), "Filter should not contain any elements when empty");
+        Assertions.assertFalse(bloomFilter.contains(null), "Filter should not contain null elements");
+    }
+
+    @Test
+    void testDifferentTypes() {
+        BloomFilter<Object> filter = new BloomFilter<>(3, 100);
+        filter.insert("string");
+        filter.insert(123);
+        filter.insert(45.67);
+
+        Assertions.assertTrue(filter.contains("string"), "Filter should contain the string 'string'");
+        Assertions.assertTrue(filter.contains(123), "Filter should contain the integer 123");
+        Assertions.assertTrue(filter.contains(45.67), "Filter should contain the double 45.67");
+        Assertions.assertFalse(filter.contains("missing"), "Filter should not contain elements that were not inserted");
+    }
+
+    @Test
+    void testFalsePositiveAfterInsertions() {
+        bloomFilter.insert("cat");
+        bloomFilter.insert("dog");
+        bloomFilter.insert("fish");
+
+        // Checking for an element that was not added
+        Assertions.assertFalse(bloomFilter.contains("bird"), "Filter should not contain 'bird' which was never inserted");
+
+        // To increase chances of false positives, we can add more items
+        for (int i = 0; i < 100; i++) {
+            bloomFilter.insert("item" + i);
+        }
+
+        Assertions.assertFalse(bloomFilter.contains("nonexistent"), "Filter should not contain 'nonexistent' which was never inserted");
+    }
+
+    @Test
+    void testBoundaryConditions() {
+        BloomFilter<String> filter = new BloomFilter<>(3, 10);
+        filter.insert("a");
+        filter.insert("b");
+        filter.insert("c");
+        filter.insert("d");
+
+        Assertions.assertTrue(filter.contains("a"), "Filter should contain 'a'");
+        Assertions.assertTrue(filter.contains("b"), "Filter should contain 'b'");
+        Assertions.assertTrue(filter.contains("c"), "Filter should contain 'c'");
+        Assertions.assertTrue(filter.contains("d"), "Filter should contain 'd'");
+        Assertions.assertFalse(filter.contains("e"), "Filter should not contain 'e' which was not inserted");
+    }
 }

From d868982a72f8945b0d3519ddaeeab606082304da Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 16:05:26 +0530
Subject: [PATCH 0596/1338] Enhance docs, add more tests in `MRUCache` (#5951)

---
 .../datastructures/caches/MRUCache.java       | 97 +++++++++++++++----
 .../datastructures/caches/MRUCacheTest.java   | 81 ++++++++++++++--
 2 files changed, 153 insertions(+), 25 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java b/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java
index 9c155be8b195..93b13e6ad654 100644
--- a/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java
+++ b/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java
@@ -4,14 +4,17 @@
 import java.util.Map;
 
 /**
- * Most recently used (MRU)
+ * Represents a Most Recently Used (MRU) Cache.
  * <p>
- * In contrast to Least Recently Used (LRU), MRU discards the most recently used
- * items first.
- * https://en.wikipedia.org/wiki/Cache_replacement_policies#Most_recently_used_(MRU)
+ * In contrast to the Least Recently Used (LRU) strategy, the MRU caching policy
+ * evicts the most recently accessed items first. This class provides methods to
+ * store key-value pairs and manage cache eviction based on this policy.
  *
- * @param <K> key type
- * @param <V> value type
+ * For more information, refer to:
+ * <a href="https://en.wikipedia.org/wiki/Cache_replacement_policies#Most_recently_used_(MRU)">MRU on Wikipedia</a>.
+ *
+ * @param <K> the type of keys maintained by this cache
+ * @param <V> the type of values associated with the keys
  */
 public class MRUCache<K, V> {
 
@@ -21,40 +24,74 @@ public class MRUCache<K, V> {
     private int cap;
     private static final int DEFAULT_CAP = 100;
 
+    /**
+     * Creates an MRUCache with the default capacity.
+     */
     public MRUCache() {
         setCapacity(DEFAULT_CAP);
     }
 
+    /**
+     * Creates an MRUCache with a specified capacity.
+     *
+     * @param cap the maximum number of items the cache can hold
+     */
+    public MRUCache(int cap) {
+        setCapacity(cap);
+    }
+
+    /**
+     * Sets the capacity of the cache and evicts items if the new capacity
+     * is less than the current number of items.
+     *
+     * @param newCapacity the new capacity to set
+     */
     private void setCapacity(int newCapacity) {
         checkCapacity(newCapacity);
-        for (int i = data.size(); i > newCapacity; i--) {
+        while (data.size() > newCapacity) {
             Entry<K, V> evicted = evict();
             data.remove(evicted.getKey());
         }
         this.cap = newCapacity;
     }
 
+    /**
+     * Checks if the specified capacity is valid.
+     *
+     * @param capacity the capacity to check
+     * @throws IllegalArgumentException if the capacity is less than or equal to zero
+     */
     private void checkCapacity(int capacity) {
         if (capacity <= 0) {
-            throw new RuntimeException("capacity must greater than 0!");
+            throw new IllegalArgumentException("Capacity must be greater than 0!");
         }
     }
 
+    /**
+     * Evicts the most recently used entry from the cache.
+     *
+     * @return the evicted entry
+     * @throws RuntimeException if the cache is empty
+     */
     private Entry<K, V> evict() {
         if (head == null) {
-            throw new RuntimeException("cache cannot be empty!");
+            throw new RuntimeException("Cache cannot be empty!");
         }
         final Entry<K, V> evicted = this.tail;
         tail = evicted.getPreEntry();
-        tail.setNextEntry(null);
+        if (tail != null) {
+            tail.setNextEntry(null);
+        }
         evicted.setNextEntry(null);
         return evicted;
     }
 
-    public MRUCache(int cap) {
-        setCapacity(cap);
-    }
-
+    /**
+     * Retrieves the value associated with the specified key.
+     *
+     * @param key the key whose associated value is to be returned
+     * @return the value associated with the specified key, or null if the key does not exist
+     */
     public V get(K key) {
         if (!data.containsKey(key)) {
             return null;
@@ -64,11 +101,19 @@ public V get(K key) {
         return entry.getValue();
     }
 
+    /**
+     * Associates the specified value with the specified key in the cache.
+     * If the key already exists, its value is updated and the entry is moved to the most recently used position.
+     * If the cache is full, the most recently used entry is evicted before adding the new entry.
+     *
+     * @param key   the key with which the specified value is to be associated
+     * @param value the value to be associated with the specified key
+     */
     public void put(K key, V value) {
         if (data.containsKey(key)) {
-            final Entry<K, V> exitingEntry = data.get(key);
-            exitingEntry.setValue(value);
-            moveEntryToLast(exitingEntry);
+            final Entry<K, V> existingEntry = data.get(key);
+            existingEntry.setValue(value);
+            moveEntryToLast(existingEntry);
             return;
         }
         Entry<K, V> newEntry;
@@ -84,6 +129,11 @@ public void put(K key, V value) {
         data.put(key, newEntry);
     }
 
+    /**
+     * Adds a new entry to the cache and updates the head and tail pointers accordingly.
+     *
+     * @param newEntry the new entry to be added
+     */
     private void addNewEntry(Entry<K, V> newEntry) {
         if (data.isEmpty()) {
             head = newEntry;
@@ -96,6 +146,11 @@ private void addNewEntry(Entry<K, V> newEntry) {
         tail = newEntry;
     }
 
+    /**
+     * Moves the specified entry to the most recently used position in the cache.
+     *
+     * @param entry the entry to be moved
+     */
     private void moveEntryToLast(Entry<K, V> entry) {
         if (tail == entry) {
             return;
@@ -117,8 +172,14 @@ private void moveEntryToLast(Entry<K, V> entry) {
         tail = entry;
     }
 
+    /**
+     * A nested class representing an entry in the cache, which holds a key-value pair
+     * and references to the previous and next entries in the linked list structure.
+     *
+     * @param <I> the type of the key
+     * @param <J> the type of the value
+     */
     static final class Entry<I, J> {
-
         private Entry<I, J> preEntry;
         private Entry<I, J> nextEntry;
         private I key;
diff --git a/src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java b/src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java
index 447feb38e788..50303ba239f6 100644
--- a/src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java
@@ -11,27 +11,27 @@ public class MRUCacheTest {
 
     @Test
     public void putAndGetIntegerValues() {
-        MRUCache<Integer, Integer> lruCache = new MRUCache<>(SIZE);
+        MRUCache<Integer, Integer> mruCache = new MRUCache<>(SIZE);
 
         for (int i = 0; i < SIZE; i++) {
-            lruCache.put(i, i);
+            mruCache.put(i, i);
         }
 
         for (int i = 0; i < SIZE; i++) {
-            assertEquals(i, lruCache.get(i));
+            assertEquals(i, mruCache.get(i));
         }
     }
 
     @Test
     public void putAndGetStringValues() {
-        MRUCache<String, String> lruCache = new MRUCache<>(SIZE);
+        MRUCache<String, String> mruCache = new MRUCache<>(SIZE);
 
         for (int i = 0; i < SIZE; i++) {
-            lruCache.put("key" + i, "value" + i);
+            mruCache.put("key" + i, "value" + i);
         }
 
         for (int i = 0; i < SIZE; i++) {
-            assertEquals("value" + i, lruCache.get("key" + i));
+            assertEquals("value" + i, mruCache.get("key" + i));
         }
     }
 
@@ -53,6 +53,73 @@ public void overCapacity() {
             mruCache.put(i, i);
         }
 
-        assertEquals(9, mruCache.get(9));
+        // After inserting 10 items, the cache should have evicted the least recently used ones.
+        assertEquals(9, mruCache.get(9)); // Most recently used
+        assertEquals(0, mruCache.get(0)); // Least recently used, should be evicted
+    }
+
+    @Test
+    public void overwriteExistingKey() {
+        MRUCache<Integer, String> mruCache = new MRUCache<>(SIZE);
+        mruCache.put(1, "one");
+        mruCache.put(1, "uno"); // Overwriting the value for key 1
+
+        assertEquals("uno", mruCache.get(1));
+        assertNull(mruCache.get(2)); // Ensure other keys are unaffected
+    }
+
+    @Test
+    public void evictionOrder() {
+        MRUCache<Integer, Integer> mruCache = new MRUCache<>(SIZE);
+
+        for (int i = 0; i < SIZE; i++) {
+            mruCache.put(i, i);
+        }
+
+        // Access a key to make it most recently used
+        mruCache.get(2);
+
+        // Add new items to trigger eviction
+        mruCache.put(5, 5);
+        mruCache.put(6, 6);
+
+        // Key 3 should be evicted since 2 is the most recently used
+        assertEquals(3, mruCache.get(3));
+        assertEquals(4, mruCache.get(4)); // Key 4 should still be available
+        assertEquals(6, mruCache.get(6)); // Key 6 should be available
+    }
+
+    @Test
+    public void cacheHandlesLargeValues() {
+        MRUCache<String, String> mruCache = new MRUCache<>(SIZE);
+
+        for (int i = 0; i < SIZE; i++) {
+            mruCache.put("key" + i, "value" + i);
+        }
+
+        // Verify values
+        for (int i = 0; i < SIZE; i++) {
+            assertEquals("value" + i, mruCache.get("key" + i));
+        }
+
+        // Add large value
+        mruCache.put("largeKey", "largeValue");
+
+        // Verify eviction of the least recently used (key 0 should be evicted)
+        assertEquals("value0", mruCache.get("key0"));
+        assertEquals("largeValue", mruCache.get("largeKey"));
+    }
+
+    @Test
+    public void testEmptyCacheBehavior() {
+        MRUCache<Integer, Integer> mruCache = new MRUCache<>(SIZE);
+
+        // Verify that accessing any key returns null
+        assertNull(mruCache.get(1));
+        assertNull(mruCache.get(100));
+
+        // Adding to cache and checking again
+        mruCache.put(1, 10);
+        assertEquals(10, mruCache.get(1));
     }
 }

From 4f7957ff140d8857e3c3d987bf14056b63286739 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 23:30:38 +0530
Subject: [PATCH 0597/1338] Enhance docs, add more tests in `DynamicArray`
 (#5952)

---
 .../dynamicarray/DynamicArray.java            | 107 ++++++++++++++----
 .../dynamicarray/DynamicArrayTest.java        |   3 +
 2 files changed, 88 insertions(+), 22 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
index a5fa9cbe94e7..cd5dc580b694 100644
--- a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
@@ -10,21 +10,24 @@
 import java.util.stream.StreamSupport;
 
 /**
- * This class implements a dynamic array.
+ * This class implements a dynamic array, which can grow or shrink in size
+ * as elements are added or removed. It provides an array-like interface
+ * with methods to add, remove, and access elements, along with iterators
+ * to traverse the elements.
  *
- * @param <E> the type that each index of the array will hold
+ * @param <E> the type of elements that this array can hold
  */
 public class DynamicArray<E> implements Iterable<E> {
 
     private static final int DEFAULT_CAPACITY = 16;
     private int size;
-    private int modCount; // Tracks structural modifications for the iterator
+    private int modCount; // Tracks structural modifications for iterator integrity
     private Object[] elements;
 
     /**
-     * Constructor with initial capacity.
+     * Constructs a new DynamicArray with the specified initial capacity.
      *
-     * @param capacity the starting length of the desired array
+     * @param capacity the initial capacity of the array
      * @throws IllegalArgumentException if the specified capacity is negative
      */
     public DynamicArray(final int capacity) {
@@ -37,14 +40,15 @@ public DynamicArray(final int capacity) {
     }
 
     /**
-     * No-args constructor with default capacity.
+     * Constructs a new DynamicArray with a default initial capacity.
      */
     public DynamicArray() {
         this(DEFAULT_CAPACITY);
     }
 
     /**
-     * Adds an element to the array. If full, creates a new array with double the size.
+     * Adds an element to the end of the array. If the array is full, it
+     * creates a new array with double the size to accommodate the new element.
      *
      * @param element the element to be added to the array
      */
@@ -55,11 +59,11 @@ public void add(final E element) {
     }
 
     /**
-     * Places an element at the desired index, expanding capacity if necessary.
+     * Places an element at the specified index, expanding capacity if necessary.
      *
-     * @param index   the index for the element to be placed
-     * @param element the element to be inserted
-     * @throws IndexOutOfBoundsException if n is less than 0 or greater or equal to the number of elements in the array
+     * @param index   the index at which the element is to be placed
+     * @param element the element to be inserted at the specified index
+     * @throws IndexOutOfBoundsException if index is less than 0 or greater than or equal to the number of elements
      */
     public void put(final int index, E element) {
         if (index < 0) {
@@ -74,11 +78,11 @@ public void put(final int index, E element) {
     }
 
     /**
-     * Gets the element at a given index.
+     * Retrieves the element at the specified index.
      *
-     * @param index the desired index of the element
+     * @param index the index of the element to retrieve
      * @return the element at the specified index
-     * @throws IndexOutOfBoundsException if n is less than 0 or greater or equal to the number of elements in the array
+     * @throws IndexOutOfBoundsException if index is less than 0 or greater than or equal to the current size
      */
     @SuppressWarnings("unchecked")
     public E get(final int index) {
@@ -89,11 +93,11 @@ public E get(final int index) {
     }
 
     /**
-     * Removes an element from the array.
+     * Removes and returns the element at the specified index.
      *
      * @param index the index of the element to be removed
-     * @return the element removed
-     * @throws IndexOutOfBoundsException if n is less than 0 or greater or equal to the number of elements in the array
+     * @return the element that was removed from the array
+     * @throws IndexOutOfBoundsException if index is less than 0 or greater than or equal to the current size
      */
     public E remove(final int index) {
         if (index < 0 || index >= size) {
@@ -106,16 +110,16 @@ public E remove(final int index) {
     }
 
     /**
-     * Gets the size of the array.
+     * Returns the current number of elements in the array.
      *
-     * @return the size
+     * @return the number of elements in the array
      */
     public int getSize() {
         return size;
     }
 
     /**
-     * Checks if the array is empty.
+     * Checks whether the array is empty.
      *
      * @return true if the array contains no elements, false otherwise
      */
@@ -123,10 +127,20 @@ public boolean isEmpty() {
         return size == 0;
     }
 
+    /**
+     * Returns a sequential stream with this collection as its source.
+     *
+     * @return a stream of the elements in the array
+     */
     public Stream<E> stream() {
         return StreamSupport.stream(spliterator(), false);
     }
 
+    /**
+     * Ensures that the array has enough capacity to hold the specified number of elements.
+     *
+     * @param minCapacity the minimum capacity required
+     */
     private void ensureCapacity(int minCapacity) {
         if (minCapacity > elements.length) {
             int newCapacity = Math.max(elements.length * 2, minCapacity);
@@ -134,6 +148,12 @@ private void ensureCapacity(int minCapacity) {
         }
     }
 
+    /**
+     * Removes the element at the specified index without resizing the array.
+     * This method shifts any subsequent elements to the left and clears the last element.
+     *
+     * @param index the index of the element to remove
+     */
     private void fastRemove(int index) {
         int numMoved = size - index - 1;
         if (numMoved > 0) {
@@ -142,31 +162,58 @@ private void fastRemove(int index) {
         elements[--size] = null; // Clear to let GC do its work
     }
 
+    /**
+     * Returns a string representation of the array, including only the elements that are currently stored.
+     *
+     * @return a string containing the elements in the array
+     */
     @Override
     public String toString() {
         return Arrays.toString(Arrays.copyOf(elements, size));
     }
 
+    /**
+     * Returns an iterator over the elements in this array in proper sequence.
+     *
+     * @return an Iterator over the elements in the array
+     */
     @Override
     public Iterator<E> iterator() {
         return new DynamicArrayIterator();
     }
 
+    /**
+     * Private iterator class for the DynamicArray.
+     */
     private final class DynamicArrayIterator implements Iterator<E> {
 
         private int cursor;
         private int expectedModCount;
 
+        /**
+         * Constructs a new iterator for the dynamic array.
+         */
         DynamicArrayIterator() {
             this.expectedModCount = modCount;
         }
 
+        /**
+         * Checks if there are more elements in the iteration.
+         *
+         * @return true if there are more elements, false otherwise
+         */
         @Override
         public boolean hasNext() {
             checkForComodification();
             return cursor < size;
         }
 
+        /**
+         * Returns the next element in the iteration.
+         *
+         * @return the next element in the iteration
+         * @throws NoSuchElementException if the iteration has no more elements
+         */
         @Override
         @SuppressWarnings("unchecked")
         public E next() {
@@ -177,22 +224,38 @@ public E next() {
             return (E) elements[cursor++];
         }
 
+        /**
+         * Removes the last element returned by this iterator.
+         *
+         * @throws IllegalStateException if the next method has not yet been called, or the remove method has already been called after the last call to the next method
+         */
         @Override
         public void remove() {
             if (cursor <= 0) {
-                throw new IllegalStateException();
+                throw new IllegalStateException("Cannot remove element before calling next()");
             }
             checkForComodification();
             DynamicArray.this.remove(--cursor);
-            expectedModCount = ++modCount;
+            expectedModCount = modCount;
         }
 
+        /**
+         * Checks for concurrent modifications to the array during iteration.
+         *
+         * @throws ConcurrentModificationException if the array has been modified structurally
+         */
         private void checkForComodification() {
             if (modCount != expectedModCount) {
                 throw new ConcurrentModificationException();
             }
         }
 
+        /**
+         * Performs the given action for each remaining element in the iterator until all elements have been processed.
+         *
+         * @param action the action to be performed for each element
+         * @throws NullPointerException if the specified action is null
+         */
         @Override
         public void forEachRemaining(Consumer<? super E> action) {
             Objects.requireNonNull(action);
diff --git a/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java b/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java
index 8e067086689b..8fdc93e1ca22 100644
--- a/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java
@@ -24,6 +24,8 @@ public void setUp() {
     public void testGetElement() {
         array.add("Alice");
         array.add("Bob");
+        array.add("Charlie");
+        array.add("David");
         assertEquals("Bob", array.get(1));
     }
 
@@ -31,6 +33,7 @@ public void testGetElement() {
     public void testGetInvalidIndex() {
         assertThrows(IndexOutOfBoundsException.class, () -> array.get(-1));
         assertThrows(IndexOutOfBoundsException.class, () -> array.get(10));
+        assertThrows(IndexOutOfBoundsException.class, () -> array.get(100));
     }
 
     @Test

From 520e46443e3a782f949b070231395129e89d6169 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 23:37:04 +0530
Subject: [PATCH 0598/1338] Enhance docs, add more tests in `FordFulkerson`
 (#5953)

---
 .../datastructures/graphs/FordFulkerson.java  |  18 +++
 .../graphs/FordFulkersonTest.java             | 122 ++++++++++++++++++
 2 files changed, 140 insertions(+)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java b/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java
index af2665cfaebb..b3a2053d54b5 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java
@@ -3,12 +3,30 @@
 import java.util.LinkedList;
 import java.util.Queue;
 
+/**
+ * This class implements the Ford-Fulkerson algorithm to compute the maximum flow
+ * in a flow network.
+ *
+ * <p>The algorithm uses breadth-first search (BFS) to find augmenting paths from
+ * the source vertex to the sink vertex, updating the flow in the network until
+ * no more augmenting paths can be found.</p>
+ */
 public final class FordFulkerson {
     private static final int INF = Integer.MAX_VALUE;
 
     private FordFulkerson() {
     }
 
+    /**
+     * Computes the maximum flow in a flow network using the Ford-Fulkerson algorithm.
+     *
+     * @param vertexCount the number of vertices in the flow network
+     * @param capacity    a 2D array representing the capacity of edges in the network
+     * @param flow        a 2D array representing the current flow in the network
+     * @param source      the source vertex in the flow network
+     * @param sink        the sink vertex in the flow network
+     * @return the total maximum flow from the source to the sink
+     */
     public static int networkFlow(int vertexCount, int[][] capacity, int[][] flow, int source, int sink) {
         int totalFlow = 0;
 
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java
index 908296aab5c1..29e373e361ad 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java
@@ -91,4 +91,126 @@ public void testComplexNetwork() {
         int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 4);
         assertEquals(19, maxFlow);
     }
+
+    @Test
+    public void testLargeNetwork() {
+        int vertexCount = 8;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // Setting up a large network
+        capacity[0][1] = 10;
+        capacity[0][2] = 5;
+        capacity[1][3] = 15;
+        capacity[2][3] = 10;
+        capacity[1][4] = 10;
+        capacity[3][5] = 10;
+        capacity[4][5] = 5;
+        capacity[4][6] = 10;
+        capacity[5][7] = 10;
+        capacity[6][7] = 15;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 7);
+        assertEquals(15, maxFlow); // Maximum flow should be 15
+    }
+
+    @Test
+    public void testMultipleSourcesAndSinks() {
+        int vertexCount = 7;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // Creating multiple sources and sinks scenario
+        capacity[0][1] = 10; // Source 1
+        capacity[0][2] = 5;
+        capacity[1][3] = 15;
+        capacity[2][3] = 10;
+        capacity[3][4] = 10; // Sink 1
+        capacity[3][5] = 5;
+        capacity[3][6] = 10; // Sink 2
+        capacity[5][6] = 10;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 4);
+        assertEquals(10, maxFlow); // Maximum flow should be 10
+    }
+
+    @Test
+    public void testDisconnectedGraph() {
+        int vertexCount = 6;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // No connection between source and sink
+        capacity[0][1] = 10; // Only one edge not connected to the sink
+        capacity[1][2] = 10;
+        capacity[3][4] = 10;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 5);
+        assertEquals(0, maxFlow); // No flow should be possible
+    }
+
+    @Test
+    public void testZeroCapacityEdge() {
+        int vertexCount = 4;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // Including a zero capacity edge
+        capacity[0][1] = 10;
+        capacity[0][2] = 0; // Zero capacity
+        capacity[1][3] = 5;
+        capacity[2][3] = 10;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 3);
+        assertEquals(5, maxFlow); // Flow only possible through 0 -> 1 -> 3
+    }
+
+    @Test
+    public void testAllEdgesZeroCapacity() {
+        int vertexCount = 5;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // All edges with zero capacity
+        capacity[0][1] = 0;
+        capacity[1][2] = 0;
+        capacity[2][3] = 0;
+        capacity[3][4] = 0;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 4);
+        assertEquals(0, maxFlow); // No flow should be possible
+    }
+
+    @Test
+    public void testCycleGraph() {
+        int vertexCount = 4;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // Setting up a cycle
+        capacity[0][1] = 10;
+        capacity[1][2] = 5;
+        capacity[2][0] = 5; // This creates a cycle
+        capacity[1][3] = 15;
+        capacity[2][3] = 10;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 3);
+        assertEquals(10, maxFlow); // Maximum flow should be 10
+    }
+
+    @Test
+    public void testFlowWithExcessCapacity() {
+        int vertexCount = 5;
+        int[][] capacity = new int[vertexCount][vertexCount];
+        int[][] flow = new int[vertexCount][vertexCount];
+
+        // Extra capacity in the flow
+        capacity[0][1] = 20;
+        capacity[1][2] = 10;
+        capacity[2][3] = 15;
+        capacity[1][3] = 5;
+
+        int maxFlow = FordFulkerson.networkFlow(vertexCount, capacity, flow, 0, 3);
+        assertEquals(15, maxFlow); // Maximum flow should be 15 (20 from 0->1 and 10->2, limited by 15->3)
+    }
 }

From b64e53cd3d949c3ff6626a7e92ac149e9b0074d6 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 23:46:19 +0530
Subject: [PATCH 0599/1338] Enhance docs, add more tests in `LRUCache` (#5950)

---
 .../datastructures/caches/LRUCache.java       |  80 +++++++++-
 .../datastructures/caches/LRUCacheTest.java   | 137 +++++++++++++++---
 2 files changed, 186 insertions(+), 31 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java b/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java
index 97818ff83351..ec39d2a6ed28 100644
--- a/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java
+++ b/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java
@@ -4,15 +4,40 @@
 import java.util.Map;
 
 /**
- * Least recently used (LRU)
- * <p>
- * Discards the least recently used items first. This algorithm requires keeping
- * track of what was used when, which is expensive if one wants to make sure the
- * algorithm always discards the least recently used item.
- * https://en.wikipedia.org/wiki/Cache_replacement_policies#Least_recently_used_(LRU)
+ * A Least Recently Used (LRU) Cache implementation.
  *
- * @param <K> key type
- * @param <V> value type
+ * <p>An LRU cache is a fixed-size cache that maintains items in order of use. When the cache reaches
+ * its capacity and a new item needs to be added, it removes the least recently used item first.
+ * This implementation provides O(1) time complexity for both get and put operations.</p>
+ *
+ * <p>Features:</p>
+ * <ul>
+ *   <li>Fixed-size cache with configurable capacity</li>
+ *   <li>Constant time O(1) operations for get and put</li>
+ *   <li>Thread-unsafe - should be externally synchronized if used in concurrent environments</li>
+ *   <li>Supports null values but not null keys</li>
+ * </ul>
+ *
+ * <p>Implementation Details:</p>
+ * <ul>
+ *   <li>Uses a HashMap for O(1) key-value lookups</li>
+ *   <li>Maintains a doubly-linked list for tracking access order</li>
+ *   <li>The head of the list contains the least recently used item</li>
+ *   <li>The tail of the list contains the most recently used item</li>
+ * </ul>
+ *
+ * <p>Example usage:</p>
+ * <pre>
+ * LRUCache<String, Integer> cache = new LRUCache<>(3); // Create cache with capacity 3
+ * cache.put("A", 1); // Cache: A=1
+ * cache.put("B", 2); // Cache: A=1, B=2
+ * cache.put("C", 3); // Cache: A=1, B=2, C=3
+ * cache.get("A");    // Cache: B=2, C=3, A=1 (A moved to end)
+ * cache.put("D", 4); // Cache: C=3, A=1, D=4 (B evicted)
+ * </pre>
+ *
+ * @param <K> the type of keys maintained by this cache
+ * @param <V> the type of mapped values
  */
 public class LRUCache<K, V> {
 
@@ -30,6 +55,11 @@ public LRUCache(int cap) {
         setCapacity(cap);
     }
 
+    /**
+     * Returns the current capacity of the cache.
+     *
+     * @param newCapacity the new capacity of the cache
+     */
     private void setCapacity(int newCapacity) {
         checkCapacity(newCapacity);
         for (int i = data.size(); i > newCapacity; i--) {
@@ -39,6 +69,11 @@ private void setCapacity(int newCapacity) {
         this.cap = newCapacity;
     }
 
+    /**
+     * Evicts the least recently used item from the cache.
+     *
+     * @return the evicted entry
+     */
     private Entry<K, V> evict() {
         if (head == null) {
             throw new RuntimeException("cache cannot be empty!");
@@ -50,12 +85,25 @@ private Entry<K, V> evict() {
         return evicted;
     }
 
+    /**
+     * Checks if the capacity is valid.
+     *
+     * @param capacity the capacity to check
+     */
     private void checkCapacity(int capacity) {
         if (capacity <= 0) {
             throw new RuntimeException("capacity must greater than 0!");
         }
     }
 
+    /**
+     * Returns the value to which the specified key is mapped, or null if this cache contains no
+     * mapping for the key.
+     *
+     * @param key the key whose associated value is to be returned
+     * @return the value to which the specified key is mapped, or null if this cache contains no
+     * mapping for the key
+     */
     public V get(K key) {
         if (!data.containsKey(key)) {
             return null;
@@ -65,6 +113,11 @@ public V get(K key) {
         return entry.getValue();
     }
 
+    /**
+     * Moves the specified entry to the end of the list.
+     *
+     * @param entry the entry to move
+     */
     private void moveNodeToLast(Entry<K, V> entry) {
         if (tail == entry) {
             return;
@@ -86,6 +139,12 @@ private void moveNodeToLast(Entry<K, V> entry) {
         tail = entry;
     }
 
+    /**
+     * Associates the specified value with the specified key in this cache.
+     *
+     * @param key the key with which the specified value is to be associated
+     * @param value the value to be associated with the specified key
+     */
     public void put(K key, V value) {
         if (data.containsKey(key)) {
             final Entry<K, V> existingEntry = data.get(key);
@@ -107,6 +166,11 @@ public void put(K key, V value) {
         data.put(key, newEntry);
     }
 
+    /**
+     * Adds a new entry to the end of the list.
+     *
+     * @param newEntry the entry to add
+     */
     private void addNewEntry(Entry<K, V> newEntry) {
         if (data.isEmpty()) {
             head = newEntry;
diff --git a/src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java b/src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java
index c56ada060022..99b9952435c4 100644
--- a/src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java
@@ -3,56 +3,147 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 public class LRUCacheTest {
-
     private static final int SIZE = 5;
+    private LRUCache<Integer, Integer> cache;
+
+    @BeforeEach
+    void setUp() {
+        cache = new LRUCache<>(SIZE);
+    }
 
     @Test
-    public void putAndGetIntegerValues() {
-        LRUCache<Integer, Integer> lruCache = new LRUCache<>(SIZE);
+    public void testBasicOperations() {
+        cache.put(1, 100);
+        assertEquals(100, cache.get(1));
+        assertNull(cache.get(2));
+    }
 
+    @Test
+    public void testEvictionPolicy() {
+        // Fill cache to capacity
         for (int i = 0; i < SIZE; i++) {
-            lruCache.put(i, i);
+            cache.put(i, i * 100);
         }
 
+        // Verify all elements are present
         for (int i = 0; i < SIZE; i++) {
-            assertEquals(i, lruCache.get(i));
+            assertEquals(i * 100, cache.get(i));
         }
+
+        // Add one more element, causing eviction of least recently used
+        cache.put(SIZE, SIZE * 100);
+
+        // First element should be evicted
+        assertNull(cache.get(0));
+        assertEquals(SIZE * 100, cache.get(SIZE));
     }
 
     @Test
-    public void putAndGetStringValues() {
-        LRUCache<String, String> lruCache = new LRUCache<>(SIZE);
-
+    public void testAccessOrder() {
+        // Fill cache
         for (int i = 0; i < SIZE; i++) {
-            lruCache.put("key" + i, "value" + i);
+            cache.put(i, i);
         }
 
-        for (int i = 0; i < SIZE; i++) {
-            assertEquals("value" + i, lruCache.get("key" + i));
-        }
+        // Access first element, making it most recently used
+        cache.get(0);
+
+        // Add new element, should evict second element (1)
+        cache.put(SIZE, SIZE);
+
+        assertEquals(0, cache.get(0)); // Should still exist
+        assertNull(cache.get(1)); // Should be evicted
+        assertEquals(SIZE, cache.get(SIZE)); // Should exist
+    }
+
+    @Test
+    public void testUpdateExistingKey() {
+        cache.put(1, 100);
+        assertEquals(100, cache.get(1));
+
+        // Update existing key
+        cache.put(1, 200);
+        assertEquals(200, cache.get(1));
     }
 
     @Test
-    public void nullKeysAndValues() {
-        LRUCache<Integer, Integer> mruCache = new LRUCache<>(SIZE);
-        mruCache.put(null, 2);
-        mruCache.put(6, null);
+    public void testNullValues() {
+        cache.put(1, null);
+        assertNull(cache.get(1));
 
-        assertEquals(2, mruCache.get(null));
-        assertNull(mruCache.get(6));
+        // Update null to non-null
+        cache.put(1, 100);
+        assertEquals(100, cache.get(1));
+
+        // Update non-null to null
+        cache.put(1, null);
+        assertNull(cache.get(1));
+    }
+
+    @Test
+    public void testStringKeysAndValues() {
+        LRUCache<String, String> stringCache = new LRUCache<>(SIZE);
+
+        stringCache.put("key1", "value1");
+        stringCache.put("key2", "value2");
+
+        assertEquals("value1", stringCache.get("key1"));
+        assertEquals("value2", stringCache.get("key2"));
+    }
+
+    @Test
+    public void testLongSequenceOfOperations() {
+        // Add elements beyond capacity multiple times
+        for (int i = 0; i < SIZE * 3; i++) {
+            cache.put(i, i * 100);
+
+            // Verify only the last SIZE elements are present
+            for (int j = Math.max(0, i - SIZE + 1); j <= i; j++) {
+                assertEquals(j * 100, cache.get(j));
+            }
+
+            // Verify elements before the window are evicted
+            if (i >= SIZE) {
+                assertNull(cache.get(i - SIZE));
+            }
+        }
     }
 
     @Test
-    public void overCapacity() {
-        LRUCache<Integer, Integer> mruCache = new LRUCache<>(SIZE);
+    void testCustomObjects() {
+        class TestObject {
+            private final String value;
 
-        for (int i = 0; i < 10; i++) {
-            mruCache.put(i, i);
+            TestObject(String value) {
+                this.value = value;
+            }
+
+            @Override
+            public boolean equals(Object obj) {
+                if (obj instanceof TestObject) {
+                    return value.equals(((TestObject) obj).value);
+                }
+                return false;
+            }
+
+            @Override
+            public int hashCode() {
+                return value == null ? 0 : value.hashCode();
+            }
         }
 
-        assertEquals(9, mruCache.get(9));
+        LRUCache<Integer, TestObject> objectCache = new LRUCache<>(SIZE);
+        TestObject obj1 = new TestObject("test1");
+        TestObject obj2 = new TestObject("test2");
+
+        objectCache.put(1, obj1);
+        objectCache.put(2, obj2);
+
+        assertEquals(obj1, objectCache.get(1));
+        assertEquals(obj2, objectCache.get(2));
     }
 }

From be0b1d58d649dba9901214d23b0110d0ca1e9b56 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 23 Oct 2024 23:51:03 +0530
Subject: [PATCH 0600/1338] Enhance docs, add more tests in `LFUCache` (#5949)

---
 .../datastructures/caches/LFUCache.java       | 15 ++--
 .../datastructures/caches/LFUCacheTest.java   | 88 +++++++++++++++----
 2 files changed, 82 insertions(+), 21 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java b/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
index 4e233224e367..f0d8ea8f7ff3 100644
--- a/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
+++ b/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
@@ -6,16 +6,21 @@
 /**
  * The {@code LFUCache} class implements a Least Frequently Used (LFU) cache.
  * An LFU cache evicts the least frequently used item when the cache reaches its capacity.
- * It keeps track of how many times each item is used and maintains a doubly linked list
- * for efficient addition and removal of items based on their frequency of use.
+ * It maintains a mapping of keys to nodes, where each node contains the key, its associated value,
+ * and a frequency count that tracks how many times the item has been accessed. A doubly linked list
+ * is used to efficiently manage the ordering of items based on their usage frequency.
  *
- * @param <K> The type of keys maintained by this cache.
- * @param <V> The type of mapped values.
+ * <p>This implementation is designed to provide O(1) time complexity for both the {@code get} and
+ * {@code put} operations, which is achieved through the use of a hashmap for quick access and a
+ * doubly linked list for maintaining the order of item frequencies.</p>
  *
  * <p>
  * Reference: <a href="https://en.wikipedia.org/wiki/Least_frequently_used">LFU Cache - Wikipedia</a>
  * </p>
  *
+ * @param <K> The type of keys maintained by this cache.
+ * @param <V> The type of mapped values.
+ *
  * @author Akshay Dubey (https://github.com/itsAkshayDubey)
  */
 public class LFUCache<K, V> {
@@ -75,7 +80,7 @@ public LFUCache(int capacity) {
 
     /**
      * Retrieves the value associated with the given key from the cache.
-     * If the key exists, the node's frequency is increased and the node is repositioned
+     * If the key exists, the node's frequency is incremented, and the node is repositioned
      * in the linked list based on its updated frequency.
      *
      * @param key The key whose associated value is to be returned.
diff --git a/src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java b/src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java
index 6a94345d625e..8ad927564aa5 100644
--- a/src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.datastructures.caches;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
@@ -22,7 +24,7 @@ void testLFUCacheWithIntegerValueShouldPass() {
         lfuCache.put(6, 60);
 
         // will return null as value with key 2 is now evicted
-        assertEquals(null, lfuCache.get(2));
+        assertNull(lfuCache.get(2));
 
         // should return 60
         assertEquals(60, lfuCache.get(6));
@@ -30,7 +32,7 @@ void testLFUCacheWithIntegerValueShouldPass() {
         // this operation will remove value with key as 3
         lfuCache.put(7, 70);
 
-        assertEquals(null, lfuCache.get(2));
+        assertNull(lfuCache.get(2));
         assertEquals(70, lfuCache.get(7));
     }
 
@@ -41,7 +43,7 @@ void testLFUCacheWithStringValueShouldPass() {
         lfuCache.put(2, "Beta");
         lfuCache.put(3, "Gamma");
         lfuCache.put(4, "Delta");
-        lfuCache.put(5, "Eplison");
+        lfuCache.put(5, "Epsilon");
 
         // get method call will increase frequency of key 1 by 1
         assertEquals("Alpha", lfuCache.get(1));
@@ -50,7 +52,7 @@ void testLFUCacheWithStringValueShouldPass() {
         lfuCache.put(6, "Digamma");
 
         // will return null as value with key 2 is now evicted
-        assertEquals(null, lfuCache.get(2));
+        assertNull(lfuCache.get(2));
 
         // should return string Digamma
         assertEquals("Digamma", lfuCache.get(6));
@@ -58,25 +60,79 @@ void testLFUCacheWithStringValueShouldPass() {
         // this operation will remove value with key as 3
         lfuCache.put(7, "Zeta");
 
-        assertEquals(null, lfuCache.get(2));
+        assertNull(lfuCache.get(2));
         assertEquals("Zeta", lfuCache.get(7));
     }
 
-    /**
-     * test addNodeWithUpdatedFrequency method
-     * @author yuluo
-     */
     @Test
-    void testAddNodeWithUpdatedFrequency() {
+    void testUpdateValueShouldPreserveFrequency() {
         LFUCache<Integer, String> lfuCache = new LFUCache<>(3);
-        lfuCache.put(1, "beijing");
-        lfuCache.put(2, "shanghai");
-        lfuCache.put(3, "gansu");
+        lfuCache.put(1, "A");
+        lfuCache.put(2, "B");
+        lfuCache.put(3, "C");
 
-        assertEquals("beijing", lfuCache.get(1));
+        assertEquals("A", lfuCache.get(1)); // Accessing key 1
+        lfuCache.put(4, "D"); // This should evict key 2
 
-        lfuCache.put(1, "shanxi");
+        assertNull(lfuCache.get(2)); // Key 2 should be evicted
+        assertEquals("C", lfuCache.get(3)); // Key 3 should still exist
+        assertEquals("A", lfuCache.get(1)); // Key 1 should still exist
 
-        assertEquals("shanxi", lfuCache.get(1));
+        lfuCache.put(1, "Updated A"); // Update the value of key 1
+        assertEquals("Updated A", lfuCache.get(1)); // Check if the update was successful
+    }
+
+    @Test
+    void testEvictionPolicyWhenFull() {
+        LFUCache<Integer, String> lfuCache = new LFUCache<>(2);
+        lfuCache.put(1, "One");
+        lfuCache.put(2, "Two");
+
+        assertEquals("One", lfuCache.get(1)); // Access key 1
+        lfuCache.put(3, "Three"); // This should evict key 2 (least frequently used)
+
+        assertNull(lfuCache.get(2)); // Key 2 should be evicted
+        assertEquals("One", lfuCache.get(1)); // Key 1 should still exist
+        assertEquals("Three", lfuCache.get(3)); // Check if key 3 exists
+    }
+
+    @Test
+    void testGetFromEmptyCacheShouldReturnNull() {
+        LFUCache<Integer, String> lfuCache = new LFUCache<>(3);
+        assertNull(lfuCache.get(1)); // Should return null as the cache is empty
+    }
+
+    @Test
+    void testPutNullValueShouldStoreNull() {
+        LFUCache<Integer, String> lfuCache = new LFUCache<>(3);
+        lfuCache.put(1, null); // Store a null value
+
+        assertNull(lfuCache.get(1)); // Should return null
+    }
+
+    @Test
+    void testInvalidCacheCapacityShouldThrowException() {
+        assertThrows(IllegalArgumentException.class, () -> new LFUCache<>(0));
+        assertThrows(IllegalArgumentException.class, () -> new LFUCache<>(-1));
+    }
+
+    @Test
+    void testMultipleAccessPatterns() {
+        LFUCache<Integer, String> lfuCache = new LFUCache<>(5);
+        lfuCache.put(1, "A");
+        lfuCache.put(2, "B");
+        lfuCache.put(3, "C");
+        lfuCache.put(4, "D");
+
+        assertEquals("A", lfuCache.get(1)); // Access 1
+        lfuCache.put(5, "E"); // Should not evict anything yet
+        lfuCache.put(6, "F"); // Evict B
+
+        assertNull(lfuCache.get(2)); // B should be evicted
+        assertEquals("C", lfuCache.get(3)); // C should still exist
+        assertEquals("D", lfuCache.get(4)); // D should still exist
+        assertEquals("A", lfuCache.get(1)); // A should still exist
+        assertEquals("E", lfuCache.get(5)); // E should exist
+        assertEquals("F", lfuCache.get(6)); // F should exist
     }
 }

From 1b51e3e9886527e8be6d8a2bc968652744c42372 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 24 Oct 2024 10:48:12 +0530
Subject: [PATCH 0601/1338] Enhance docs, add more tests in `JohnsonsAlgorithm`
 (#5964)

---
 .../graphs/JohnsonsAlgorithm.java             |  15 ++-
 .../graphs/JohnsonsAlgorithmTest.java         | 100 ++++++++++--------
 2 files changed, 59 insertions(+), 56 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java
index 76c11f782985..351bd5b009e8 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java
@@ -21,17 +21,18 @@
  */
 public final class JohnsonsAlgorithm {
 
-    // Constant representing infinity
     private static final double INF = Double.POSITIVE_INFINITY;
 
-    /**
-     * A private constructor to hide the implicit public one.
-     */
     private JohnsonsAlgorithm() {
     }
 
     /**
      * Executes Johnson's algorithm on the given graph.
+     * Steps:
+     * 1. Add a new vertex to the graph and run Bellman-Ford to compute modified weights
+     * 2. t the graph using the modified weights
+     * 3. Run Dijkstra's algorithm for each vertex to compute the shortest paths
+     * The final result is a 2D array of shortest distances between all pairs of vertices.
      *
      * @param graph The input graph represented as an adjacency matrix.
      * @return A 2D array representing the shortest distances between all pairs of vertices.
@@ -40,13 +41,10 @@ public static double[][] johnsonAlgorithm(double[][] graph) {
         int numVertices = graph.length;
         double[][] edges = convertToEdgeList(graph);
 
-        // Step 1: Add a new vertex and run Bellman-Ford
         double[] modifiedWeights = bellmanFord(edges, numVertices);
 
-        // Step 2: Reweight the graph
         double[][] reweightedGraph = reweightGraph(graph, modifiedWeights);
 
-        // Step 3: Run Dijkstra's algorithm for each vertex
         double[][] shortestDistances = new double[numVertices][numVertices];
         for (int source = 0; source < numVertices; source++) {
             shortestDistances[source] = dijkstra(reweightedGraph, source, modifiedWeights);
@@ -74,7 +72,6 @@ public static double[][] convertToEdgeList(double[][] graph) {
             }
         }
 
-        // Convert the List to a 2D array
         return edgeList.toArray(new double[0][]);
     }
 
@@ -89,7 +86,7 @@ public static double[][] convertToEdgeList(double[][] graph) {
     private static double[] bellmanFord(double[][] edges, int numVertices) {
         double[] dist = new double[numVertices + 1];
         Arrays.fill(dist, INF);
-        dist[numVertices] = 0; // Distance to the new source vertex is 0
+        dist[numVertices] = 0;
 
         // Add edges from the new vertex to all original vertices
         double[][] allEdges = Arrays.copyOf(edges, edges.length + numVertices);
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java
index 0ae837cd944f..7ea2449202e0 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java
@@ -23,114 +23,120 @@ class JohnsonsAlgorithmTest {
      */
     @Test
     void testSimpleGraph() {
-        // Test case for a simple graph without negative edges
         double[][] graph = {{0, 4, INF, INF}, {INF, 0, 1, INF}, {INF, INF, 0, 2}, {INF, INF, INF, 0}};
-
         double[][] result = JohnsonsAlgorithm.johnsonAlgorithm(graph);
-
         double[][] expected = {{0, 4, 5, 7}, {INF, 0, 1, 3}, {INF, INF, 0, 2}, {INF, INF, INF, 0}};
-
         assertArrayEquals(expected, result);
     }
 
     /**
-     * Tests Johnson's Algorithm on a graph with negative edges but no
-     * negative weight cycles. Verifies the algorithm handles negative
-     * edge weights correctly.
+     * Tests Johnson's Algorithm on a graph with negative edges but no negative weight cycles.
      */
     @Test
     void testGraphWithNegativeEdges() {
-        // Graph with negative edges but no negative weight cycles
         double[][] graph = {{0, -1, 4}, {INF, 0, 3}, {INF, INF, 0}};
-
         double[][] result = JohnsonsAlgorithm.johnsonAlgorithm(graph);
-
         double[][] expected = {{0, INF, 4}, {INF, 0, 3}, {INF, INF, 0}};
-
         assertArrayEquals(expected, result);
     }
 
     /**
-     * Tests the behavior of Johnson's Algorithm on a graph with a negative
-     * weight cycle. Expects an IllegalArgumentException to be thrown
-     * due to the presence of the cycle.
+     * Tests Johnson's Algorithm on a graph with a negative weight cycle.
      */
     @Test
     void testNegativeWeightCycle() {
-        // Graph with a negative weight cycle
         double[][] graph = {{0, 1, INF}, {INF, 0, -1}, {-1, INF, 0}};
-
-        // Johnson's algorithm should throw an exception when a negative cycle is detected
-        assertThrows(IllegalArgumentException.class, () -> { JohnsonsAlgorithm.johnsonAlgorithm(graph); });
+        assertThrows(IllegalArgumentException.class, () -> JohnsonsAlgorithm.johnsonAlgorithm(graph));
     }
 
     /**
-     * Tests Dijkstra's algorithm as a part of Johnson's algorithm implementation
-     * on a small graph. Verifies that the shortest path is correctly calculated.
+     * Tests Dijkstra's algorithm on a small graph as part of Johnson's Algorithm.
      */
     @Test
     void testDijkstra() {
-        // Testing Dijkstra's algorithm with a small graph
         double[][] graph = {{0, 1, 2}, {INF, 0, 3}, {INF, INF, 0}};
-
-        double[] modifiedWeights = {0, 0, 0}; // No reweighting in this simple case
-
+        double[] modifiedWeights = {0, 0, 0};
         double[] result = JohnsonsAlgorithm.dijkstra(graph, 0, modifiedWeights);
         double[] expected = {0, 1, 2};
-
         assertArrayEquals(expected, result);
     }
 
     /**
      * Tests the conversion of an adjacency matrix to an edge list.
-     * Verifies that the conversion process generates the correct edge list.
      */
     @Test
     void testEdgeListConversion() {
-        // Test the conversion of adjacency matrix to edge list
         double[][] graph = {{0, 5, INF}, {INF, 0, 2}, {INF, INF, 0}};
-
-        // Running convertToEdgeList
         double[][] edges = JohnsonsAlgorithm.convertToEdgeList(graph);
-
-        // Expected edge list: (0 -> 1, weight 5), (1 -> 2, weight 2)
         double[][] expected = {{0, 1, 5}, {1, 2, 2}};
-
-        // Verify the edge list matches the expected values
         assertArrayEquals(expected, edges);
     }
 
     /**
-     * Tests the reweighting of a graph as a part of Johnson's Algorithm.
-     * Verifies that the reweighted graph produces correct results.
+     * Tests the reweighting of a graph.
      */
     @Test
     void testReweightGraph() {
-        // Test reweighting of the graph
         double[][] graph = {{0, 2, 9}, {INF, 0, 1}, {INF, INF, 0}};
-        double[] modifiedWeights = {1, 2, 3}; // Arbitrary weight function
-
+        double[] modifiedWeights = {1, 2, 3};
         double[][] reweightedGraph = JohnsonsAlgorithm.reweightGraph(graph, modifiedWeights);
-
-        // Expected reweighted graph:
         double[][] expected = {{0, 1, 7}, {INF, 0, 0}, {INF, INF, 0}};
-
         assertArrayEquals(expected, reweightedGraph);
     }
 
     /**
-     * Tests the minDistance method used in Dijkstra's algorithm to find
-     * the vertex with the minimum distance that has not yet been visited.
+     * Tests the minDistance method used in Dijkstra's algorithm.
      */
     @Test
     void testMinDistance() {
-        // Test minDistance method
         double[] dist = {INF, 3, 1, INF};
         boolean[] visited = {false, false, false, false};
-
         int minIndex = JohnsonsAlgorithm.minDistance(dist, visited);
-
-        // The vertex with minimum distance is vertex 2 with a distance of 1
         assertEquals(2, minIndex);
     }
+
+    /**
+     * Tests Johnson's Algorithm on a graph where all vertices are disconnected.
+     */
+    @Test
+    void testDisconnectedGraph() {
+        double[][] graph = {{0, INF, INF}, {INF, 0, INF}, {INF, INF, 0}};
+        double[][] result = JohnsonsAlgorithm.johnsonAlgorithm(graph);
+        double[][] expected = {{0, INF, INF}, {INF, 0, INF}, {INF, INF, 0}};
+        assertArrayEquals(expected, result);
+    }
+
+    /**
+     * Tests Johnson's Algorithm on a fully connected graph.
+     */
+    @Test
+    void testFullyConnectedGraph() {
+        double[][] graph = {{0, 1, 2}, {1, 0, 1}, {2, 1, 0}};
+        double[][] result = JohnsonsAlgorithm.johnsonAlgorithm(graph);
+        double[][] expected = {{0, 1, 2}, {1, 0, 1}, {2, 1, 0}};
+        assertArrayEquals(expected, result);
+    }
+
+    /**
+     * Tests Dijkstra's algorithm on a graph with multiple shortest paths.
+     */
+    @Test
+    void testDijkstraMultipleShortestPaths() {
+        double[][] graph = {{0, 1, 2, INF}, {INF, 0, INF, 1}, {INF, INF, 0, 1}, {INF, INF, INF, 0}};
+        double[] modifiedWeights = {0, 0, 0, 0};
+        double[] result = JohnsonsAlgorithm.dijkstra(graph, 0, modifiedWeights);
+        double[] expected = {0, 1, 2, 2};
+        assertArrayEquals(expected, result);
+    }
+
+    /**
+     * Tests Johnson's Algorithm with a graph where all edge weights are zero.
+     */
+    @Test
+    void testGraphWithZeroWeights() {
+        double[][] graph = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};
+        double[][] result = JohnsonsAlgorithm.johnsonAlgorithm(graph);
+        double[][] expected = {{0, INF, INF}, {INF, 0, INF}, {INF, INF, 0}};
+        assertArrayEquals(expected, result);
+    }
 }

From 3a9a2c4160747d5219f007e51155e5b8d9bf2625 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 24 Oct 2024 10:52:24 +0530
Subject: [PATCH 0602/1338] Enhance docs, add more tests in `HamiltonianCycle`
 (#5963)

---
 .../graphs/HamiltonianCycle.java              | 65 +++++++++----------
 .../graphs/HamiltonianCycleTest.java          | 61 ++++++++++++++++-
 2 files changed, 92 insertions(+), 34 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java b/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
index f12e3892b1b2..5c95850c4971 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java
@@ -1,8 +1,14 @@
 package com.thealgorithms.datastructures.graphs;
 
+import java.util.Arrays;
+
 /**
- * Java program for Hamiltonian Cycle
- * <a href="https://en.wikipedia.org/wiki/Hamiltonian_path">wikipedia</a>
+ * Java program to find a Hamiltonian Cycle in a graph.
+ * A Hamiltonian Cycle is a cycle that visits every vertex exactly once
+ * and returns to the starting vertex.
+ *
+ * <p>For more details, see the
+ * <a href="https://en.wikipedia.org/wiki/Hamiltonian_path">Wikipedia article</a>.
  *
  * @author  <a href="https://github.com/itsAkshayDubey">Akshay Dubey</a>
  */
@@ -14,30 +20,30 @@ public class HamiltonianCycle {
     private int[][] graph;
 
     /**
-     * Find hamiltonian cycle for given graph G(V,E)
+     * Finds a Hamiltonian Cycle for the given graph.
      *
-     * @param graph Adjacency matrix of a graph G(V, E)
-     *              for which hamiltonian path is to be found
-     * @return Array containing hamiltonian cycle
-     *         else returns 1D array with value -1.
+     * @param graph Adjacency matrix representing the graph G(V, E), where V is
+     *              the set of vertices and E is the set of edges.
+     * @return An array representing the Hamiltonian cycle if found, otherwise an
+     *         array filled with -1 indicating no Hamiltonian cycle exists.
      */
     public int[] findHamiltonianCycle(int[][] graph) {
+        // Single vertex graph
+        if (graph.length == 1) {
+            return new int[] {0, 0};
+        }
+
         this.vertex = graph.length;
         this.cycle = new int[this.vertex + 1];
 
-        // Initialize path array with -1 value
-        for (int i = 0; i < this.cycle.length; i++) {
-            this.cycle[i] = -1;
-        }
+        // Initialize the cycle array with -1 to represent unvisited vertices
+        Arrays.fill(this.cycle, -1);
 
         this.graph = graph;
-
         this.cycle[0] = 0;
         this.pathCount = 1;
         if (!isPathFound(0)) {
-            for (int i = 0; i < this.cycle.length; i++) {
-                this.cycle[i] = -1;
-            }
+            Arrays.fill(this.cycle, -1);
         } else {
             this.cycle[this.cycle.length - 1] = this.cycle[0];
         }
@@ -46,11 +52,10 @@ public int[] findHamiltonianCycle(int[][] graph) {
     }
 
     /**
-     * function to find paths recursively
-     * Find paths recursively from given vertex
+     * Recursively searches for a Hamiltonian cycle from the given vertex.
      *
-     * @param vertex Vertex from which path is to be found
-     * @returns true if path is found false otherwise
+     * @param vertex The current vertex from which to explore paths.
+     * @return {@code true} if a Hamiltonian cycle is found, otherwise {@code false}.
      */
     public boolean isPathFound(int vertex) {
         boolean isLastVertexConnectedToStart = this.graph[vertex][0] == 1 && this.pathCount == this.vertex;
@@ -58,31 +63,26 @@ public boolean isPathFound(int vertex) {
             return true;
         }
 
-        /* all vertices selected but last vertex not linked to 0 **/
+        // If all vertices are visited but the last vertex is not connected to the start
         if (this.pathCount == this.vertex) {
             return false;
         }
 
         for (int v = 0; v < this.vertex; v++) {
-            /* if connected **/
-            if (this.graph[vertex][v] == 1) {
-                /* add to path **/
-                this.cycle[this.pathCount++] = v;
-
-                /* remove connection **/
+            if (this.graph[vertex][v] == 1) { // Check if there is an edge
+                this.cycle[this.pathCount++] = v; // Add the vertex to the cycle
                 this.graph[vertex][v] = 0;
                 this.graph[v][vertex] = 0;
 
-                /* if vertex not already selected solve recursively **/
+                // Recursively attempt to complete the cycle
                 if (!isPresent(v)) {
                     return isPathFound(v);
                 }
 
-                /* restore connection **/
+                // Restore the edge if the path does not work
                 this.graph[vertex][v] = 1;
                 this.graph[v][vertex] = 1;
 
-                /* remove path **/
                 this.cycle[--this.pathCount] = -1;
             }
         }
@@ -90,10 +90,10 @@ public boolean isPathFound(int vertex) {
     }
 
     /**
-     * function to check if path is already selected
-     * Check if path is already selected
+     * Checks if a vertex is already part of the current Hamiltonian path.
      *
-     * @param vertex Starting vertex
+     * @param vertex The vertex to check.
+     * @return {@code true} if the vertex is already in the path, otherwise {@code false}.
      */
     public boolean isPresent(int vertex) {
         for (int i = 0; i < pathCount - 1; i++) {
@@ -101,7 +101,6 @@ public boolean isPresent(int vertex) {
                 return true;
             }
         }
-
         return false;
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java
index ed7c886d784e..4529606d7797 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java
@@ -6,7 +6,7 @@
 
 class HamiltonianCycleTest {
 
-    private HamiltonianCycle hamiltonianCycle = new HamiltonianCycle();
+    private final HamiltonianCycle hamiltonianCycle = new HamiltonianCycle();
 
     @Test
     void testFindHamiltonianCycleShouldReturnHamiltonianCycle() {
@@ -36,4 +36,63 @@ void testFindHamiltonianCycleShouldReturnInfinityArray() {
 
         assertArrayEquals(expectedArray, hamiltonianCycle.findHamiltonianCycle(inputArray));
     }
+
+    @Test
+    void testSingleVertexGraph() {
+        int[] expectedArray = {0, 0};
+        int[][] inputArray = {{0}};
+
+        assertArrayEquals(expectedArray, hamiltonianCycle.findHamiltonianCycle(inputArray));
+    }
+
+    @Test
+    void testDisconnectedGraphShouldReturnInfinityArray() {
+        int[] expectedArray = {-1, -1, -1, -1, -1};
+        int[][] inputArray = {{0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}};
+
+        assertArrayEquals(expectedArray, hamiltonianCycle.findHamiltonianCycle(inputArray));
+    }
+
+    @Test
+    void testCompleteGraphShouldReturnHamiltonianCycle() {
+        int[] expectedArray = {0, 1, 2, 3, 4, 0};
+        int[][] inputArray = {
+            {0, 1, 1, 1, 1},
+            {1, 0, 1, 1, 1},
+            {1, 1, 0, 1, 1},
+            {1, 1, 1, 0, 1},
+            {1, 1, 1, 1, 0},
+        };
+
+        assertArrayEquals(expectedArray, hamiltonianCycle.findHamiltonianCycle(inputArray));
+    }
+
+    @Test
+    void testGraphWithNoEdgesShouldReturnInfinityArray() {
+        int[] expectedArray = {-1, -1, -1, -1, -1, -1};
+
+        int[][] inputArray = {
+            {0, 0, 0, 0, 0},
+            {0, 0, 0, 0, 0},
+            {0, 0, 0, 0, 0},
+            {0, 0, 0, 0, 0},
+            {0, 0, 0, 0, 0},
+        };
+
+        assertArrayEquals(expectedArray, hamiltonianCycle.findHamiltonianCycle(inputArray));
+    }
+
+    @Test
+    void testLargeGraphWithHamiltonianCycle() {
+        int[] expectedArray = {0, 1, 2, 3, 4, 0};
+        int[][] inputArray = {
+            {0, 1, 0, 1, 1},
+            {1, 0, 1, 1, 0},
+            {0, 1, 0, 1, 1},
+            {1, 1, 1, 0, 1},
+            {1, 0, 1, 1, 0},
+        };
+
+        assertArrayEquals(expectedArray, hamiltonianCycle.findHamiltonianCycle(inputArray));
+    }
 }

From 13be2501c29c0997c511f39aa9fe33957a1ea132 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 24 Oct 2024 10:59:16 +0530
Subject: [PATCH 0603/1338] Enhance docs, add tests in KahnsAlgorithm (#5965)

---
 DIRECTORY.md                                  |  1 +
 .../datastructures/graphs/KahnsAlgorithm.java | 84 ++++++++++++-------
 .../graphs/KahnsAlgorithmTest.java            | 77 +++++++++++++++++
 3 files changed, 134 insertions(+), 28 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithmTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 4f4276860928..0539f0df1350 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -810,6 +810,7 @@
               * [FordFulkersonTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java)
               * [HamiltonianCycleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java)
               * [JohnsonsAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java)
+              * [KahnsAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithmTest.java)
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
               * [TarjansAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
               * [WelshPowellTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
index d5035cf625a6..9a97bc3f4808 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java
@@ -9,96 +9,120 @@
 import java.util.Set;
 
 /**
- * A class that represents the adjaceny list of a graph
+ * A class representing the adjacency list of a directed graph. The adjacency list
+ * maintains a mapping of vertices to their adjacent vertices.
+ *
+ * @param <E> the type of vertices, extending Comparable to ensure that vertices
+ * can be compared
  */
 class AdjacencyList<E extends Comparable<E>> {
 
     Map<E, ArrayList<E>> adj;
 
+    /**
+     * Constructor to initialize the adjacency list.
+     */
     AdjacencyList() {
-        adj = new LinkedHashMap<E, ArrayList<E>>();
+        adj = new LinkedHashMap<>();
     }
 
     /**
-     * This function adds an Edge to the adjaceny list
+     * Adds a directed edge from one vertex to another in the adjacency list.
+     * If the vertex does not exist, it will be added to the list.
      *
-     * @param from , the vertex the edge is from
-     * @param to, the vertex the edge is going to
+     * @param from the starting vertex of the directed edge
+     * @param to   the destination vertex of the directed edge
      */
     void addEdge(E from, E to) {
-        try {
-            adj.get(from).add(to);
-        } catch (Exception E) {
-            adj.put(from, new ArrayList<E>());
-            adj.get(from).add(to);
+        if (!adj.containsKey(from)) {
+            adj.put(from, new ArrayList<>());
         }
+        adj.get(from).add(to);
         if (!adj.containsKey(to)) {
-            adj.put(to, new ArrayList<E>());
+            adj.put(to, new ArrayList<>());
         }
     }
 
     /**
-     * @param v, A vertex in a graph
-     * @return returns an ArrayList of all the adjacents of vertex v
+     * Retrieves the list of adjacent vertices for a given vertex.
+     *
+     * @param v the vertex whose adjacent vertices are to be fetched
+     * @return an ArrayList of adjacent vertices for vertex v
      */
     ArrayList<E> getAdjacents(E v) {
         return adj.get(v);
     }
 
     /**
-     * @return returns a set of all vertices in the graph
+     * Retrieves the set of all vertices present in the graph.
+     *
+     * @return a set containing all vertices in the graph
      */
     Set<E> getVertices() {
         return adj.keySet();
     }
 }
 
+/**
+ * A class that performs topological sorting on a directed graph using Kahn's algorithm.
+ *
+ * @param <E> the type of vertices, extending Comparable to ensure that vertices
+ * can be compared
+ */
 class TopologicalSort<E extends Comparable<E>> {
 
     AdjacencyList<E> graph;
     Map<E, Integer> inDegree;
 
+    /**
+     * Constructor to initialize the topological sorting class with a given graph.
+     *
+     * @param graph the directed graph represented as an adjacency list
+     */
     TopologicalSort(AdjacencyList<E> graph) {
         this.graph = graph;
     }
 
     /**
-     * Calculates the in degree of all vertices
+     * Calculates the in-degree of all vertices in the graph. The in-degree is
+     * the number of edges directed into a vertex.
      */
     void calculateInDegree() {
         inDegree = new HashMap<>();
         for (E vertex : graph.getVertices()) {
-            if (!inDegree.containsKey(vertex)) {
-                inDegree.put(vertex, 0);
-            }
+            inDegree.putIfAbsent(vertex, 0);
             for (E adjacent : graph.getAdjacents(vertex)) {
-                try {
-                    inDegree.put(adjacent, inDegree.get(adjacent) + 1);
-                } catch (Exception e) {
-                    inDegree.put(adjacent, 1);
-                }
+                inDegree.put(adjacent, inDegree.getOrDefault(adjacent, 0) + 1);
             }
         }
     }
 
     /**
-     * Returns an ArrayList with vertices arranged in topological order
+     * Returns an ArrayList containing the vertices of the graph arranged in
+     * topological order. Topological sorting ensures that for any directed edge
+     * (u, v), vertex u appears before vertex v in the ordering.
+     *
+     * @return an ArrayList of vertices in topological order
+     * @throws IllegalStateException if the graph contains a cycle
      */
     ArrayList<E> topSortOrder() {
         calculateInDegree();
-        Queue<E> q = new LinkedList<E>();
+        Queue<E> q = new LinkedList<>();
 
-        for (final var entry : inDegree.entrySet()) {
+        for (var entry : inDegree.entrySet()) {
             if (entry.getValue() == 0) {
                 q.add(entry.getKey());
             }
         }
 
         ArrayList<E> answer = new ArrayList<>();
+        int processedVertices = 0;
 
         while (!q.isEmpty()) {
             E current = q.poll();
             answer.add(current);
+            processedVertices++;
+
             for (E adjacent : graph.getAdjacents(current)) {
                 inDegree.put(adjacent, inDegree.get(adjacent) - 1);
                 if (inDegree.get(adjacent) == 0) {
@@ -107,12 +131,16 @@ ArrayList<E> topSortOrder() {
             }
         }
 
+        if (processedVertices != graph.getVertices().size()) {
+            throw new IllegalStateException("Graph contains a cycle, topological sort not possible");
+        }
+
         return answer;
     }
 }
 
 /**
- * A driver class that sorts a given graph in topological order.
+ * A driver class that sorts a given graph in topological order using Kahn's algorithm.
  */
 public final class KahnsAlgorithm {
     private KahnsAlgorithm() {
@@ -130,7 +158,7 @@ public static void main(String[] args) {
 
         TopologicalSort<String> topSort = new TopologicalSort<>(graph);
 
-        // Printing the order
+        // Printing the topological order
         for (String s : topSort.topSortOrder()) {
             System.out.print(s + " ");
         }
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithmTest.java
new file mode 100644
index 000000000000..8d096a4b4459
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithmTest.java
@@ -0,0 +1,77 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.ArrayList;
+import org.junit.jupiter.api.Test;
+
+class KahnsAlgorithmTest {
+
+    @Test
+    void testBasicGraph() {
+        // Test case with a basic directed acyclic graph (DAG)
+        AdjacencyList<String> graph = new AdjacencyList<>();
+        graph.addEdge("a", "b");
+        graph.addEdge("c", "a");
+        graph.addEdge("a", "d");
+        graph.addEdge("b", "d");
+
+        TopologicalSort<String> topSort = new TopologicalSort<>(graph);
+        ArrayList<String> result = topSort.topSortOrder();
+
+        String[] expectedOrder = {"c", "a", "b", "d"};
+        assertArrayEquals(expectedOrder, result.toArray());
+    }
+
+    @Test
+    void testGraphWithMultipleSources() {
+        // Test case where graph has multiple independent sources
+        AdjacencyList<String> graph = new AdjacencyList<>();
+        graph.addEdge("a", "c");
+        graph.addEdge("b", "c");
+
+        TopologicalSort<String> topSort = new TopologicalSort<>(graph);
+        ArrayList<String> result = topSort.topSortOrder();
+
+        String[] expectedOrder = {"a", "b", "c"};
+        assertArrayEquals(expectedOrder, result.toArray());
+    }
+
+    @Test
+    void testDisconnectedGraph() {
+        // Test case for disconnected graph
+        AdjacencyList<String> graph = new AdjacencyList<>();
+        graph.addEdge("a", "b");
+        graph.addEdge("c", "d");
+
+        TopologicalSort<String> topSort = new TopologicalSort<>(graph);
+        ArrayList<String> result = topSort.topSortOrder();
+
+        String[] expectedOrder = {"a", "c", "b", "d"};
+        assertArrayEquals(expectedOrder, result.toArray());
+    }
+
+    @Test
+    void testGraphWithCycle() {
+        // Test case for a graph with a cycle - topological sorting is not possible
+        AdjacencyList<String> graph = new AdjacencyList<>();
+        graph.addEdge("a", "b");
+        graph.addEdge("b", "c");
+        graph.addEdge("c", "a");
+
+        TopologicalSort<String> topSort = new TopologicalSort<>(graph);
+
+        assertThrows(IllegalStateException.class, () -> topSort.topSortOrder());
+    }
+
+    @Test
+    void testSingleNodeGraph() {
+        AdjacencyList<String> graph = new AdjacencyList<>();
+        graph.addEdge("a", "a"); // self-loop
+
+        TopologicalSort<String> topSort = new TopologicalSort<>(graph);
+
+        assertThrows(IllegalStateException.class, () -> topSort.topSortOrder());
+    }
+}

From 578e5a73df2c2499f5e2b38cddb58138f72eebc0 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 24 Oct 2024 11:08:08 +0530
Subject: [PATCH 0604/1338] Enhance docs, add more tests in `Kosaraju` (#5966)

---
 .../datastructures/graphs/Kosaraju.java       | 155 ++++++++++--------
 .../datastructures/graphs/KosarajuTest.java   |  74 ++++++---
 2 files changed, 143 insertions(+), 86 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java b/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java
index c5f15839f997..78a184f042b5 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java
@@ -5,82 +5,91 @@
 import java.util.Stack;
 
 /**
- * Java program that implements Kosaraju Algorithm.
- * @author <a href="https://github.com/shivu2002a">Shivanagouda S A</a>
+ * This class implements the Kosaraju Algorithm to find all the Strongly Connected Components (SCCs)
+ * of a directed graph. Kosaraju's algorithm runs in linear time and leverages the concept that
+ * the SCCs of a directed graph remain the same in its transpose (reverse) graph.
+ *
  * <p>
- * Kosaraju algorithm is a linear time algorithm to find the strongly connected components of a
-directed graph, which, from here onwards will be referred by SCC. It leverages the fact that the
-transpose graph (same graph with all the edges reversed) has exactly the same SCCs as the original
-graph.
-
- * A graph is said to be strongly connected if every vertex is reachable from every other vertex.
-The SCCs of a directed graph form a partition into subgraphs that are themselves strongly
-connected. Single node is always a SCC.
-
- * Example:
-
-0 <--- 2 -------> 3 -------- > 4 ---- > 7
-|     ^                      | ^       ^
-|    /                       |  \     /
-|   /                        |   \   /
-v  /                         v    \ /
-1                            5 --> 6
-
-For the above graph, the SCC list goes as follows:
-0, 1, 2
-3
-4, 5, 6
-7
-
-We can also see that order of the nodes in an SCC doesn't matter since they are in cycle.
-
-{@summary}
- * Kosaraju Algorithm:
-1. Perform DFS traversal of the graph. Push node to stack before returning. This gives edges
-sorted by lowest finish time.
-2. Find the transpose graph by reversing the edges.
-3. Pop nodes one by one from the stack and again to DFS on the modified graph.
-
-The transpose graph of the above graph:
-0 ---> 2 <------- 3 <------- 4 <------ 7
-^     /                      ^ \       /
-|    /                       |  \     /
-|   /                        |   \   /
-|  v                         |    v v
-1                            5 <--- 6
-
-We can observe that this graph has the same SCC as that of original graph.
-
+ * A strongly connected component (SCC) of a directed graph is a subgraph where every vertex
+ * is reachable from every other vertex in the subgraph. The Kosaraju algorithm is particularly
+ * efficient for finding SCCs because it performs two Depth First Search (DFS) passes on the
+ * graph and its transpose.
+ * </p>
+ *
+ * <p><strong>Algorithm:</strong></p>
+ * <ol>
+ *     <li>Perform DFS on the original graph and push nodes to a stack in the order of their finishing time.</li>
+ *     <li>Generate the transpose (reversed edges) of the original graph.</li>
+ *     <li>Perform DFS on the transpose graph, using the stack from the first DFS. Each DFS run on the transpose graph gives a SCC.</li>
+ * </ol>
+ *
+ * <p><strong>Example Graph:</strong></p>
+ * <pre>
+ * 0 <--- 2 -------> 3 -------- > 4 ---- > 7
+ * |     ^                      | ^       ^
+ * |    /                       |  \     /
+ * |   /                        |   \   /
+ * v  /                         v    \ /
+ * 1                            5 --> 6
+ * </pre>
+ *
+ * <p><strong>SCCs in the example:</strong></p>
+ * <ul>
+ *     <li>{0, 1, 2}</li>
+ *     <li>{3}</li>
+ *     <li>{4, 5, 6}</li>
+ *     <li>{7}</li>
+ * </ul>
+ *
+ * <p>The order of nodes in an SCC does not matter because every node in an SCC is reachable from every other node within the same SCC.</p>
+ *
+ * <p><strong>Graph Transpose Example:</strong></p>
+ * <pre>
+ * 0 ---> 2 <------- 3 <------- 4 <------ 7
+ * ^     /                      ^ \       /
+ * |    /                       |  \     /
+ * |   /                        |   \   /
+ * |  v                         |    v v
+ * 1                            5 <--- 6
+ * </pre>
+ *
+ * The SCCs of this transpose graph are the same as the original graph.
  */
-
 public class Kosaraju {
 
-    // Sort edges according to lowest finish time
-    Stack<Integer> stack = new Stack<Integer>();
+    // Stack to sort edges by the lowest finish time (used in the first DFS)
+    private final Stack<Integer> stack = new Stack<>();
 
-    // Store each component
+    // Store each strongly connected component
     private List<Integer> scc = new ArrayList<>();
 
-    // All the strongly connected components
-    private List<List<Integer>> sccsList = new ArrayList<>();
+    // List of all SCCs
+    private final List<List<Integer>> sccsList = new ArrayList<>();
 
     /**
+     * Main function to perform Kosaraju's Algorithm.
+     * Steps:
+     * 1. Sort nodes by the lowest finishing time
+     * 2. Create the transpose (reverse edges) of the original graph
+     * 3. Find SCCs by performing DFS on the transpose graph
+     * 4. Return the list of SCCs
      *
-     * @param v Node count
-     * @param list Adjacency list of graph
-     * @return List of SCCs
+     * @param v the number of vertices in the graph
+     * @param list the adjacency list representing the directed graph
+     * @return a list of SCCs where each SCC is a list of vertices
      */
     public List<List<Integer>> kosaraju(int v, List<List<Integer>> list) {
-
         sortEdgesByLowestFinishTime(v, list);
-
         List<List<Integer>> transposeGraph = createTransposeMatrix(v, list);
-
         findStronglyConnectedComponents(v, transposeGraph);
-
         return sccsList;
     }
 
+    /**
+     * Performs DFS on the original graph to sort nodes by their finishing times.
+     * @param v the number of vertices in the graph
+     * @param list the adjacency list representing the original graph
+     */
     private void sortEdgesByLowestFinishTime(int v, List<List<Integer>> list) {
         int[] vis = new int[v];
         for (int i = 0; i < v; i++) {
@@ -90,8 +99,14 @@ private void sortEdgesByLowestFinishTime(int v, List<List<Integer>> list) {
         }
     }
 
+    /**
+     * Creates the transpose (reverse) of the original graph.
+     * @param v the number of vertices in the graph
+     * @param list the adjacency list representing the original graph
+     * @return the adjacency list representing the transposed graph
+     */
     private List<List<Integer>> createTransposeMatrix(int v, List<List<Integer>> list) {
-        var transposeGraph = new ArrayList<List<Integer>>(v);
+        List<List<Integer>> transposeGraph = new ArrayList<>(v);
         for (int i = 0; i < v; i++) {
             transposeGraph.add(new ArrayList<>());
         }
@@ -104,14 +119,14 @@ private List<List<Integer>> createTransposeMatrix(int v, List<List<Integer>> lis
     }
 
     /**
-     *
-     * @param v Node count
-     * @param transposeGraph Transpose of the given adjacency list
+     * Finds the strongly connected components (SCCs) by performing DFS on the transposed graph.
+     * @param v the number of vertices in the graph
+     * @param transposeGraph the adjacency list representing the transposed graph
      */
     public void findStronglyConnectedComponents(int v, List<List<Integer>> transposeGraph) {
         int[] vis = new int[v];
         while (!stack.isEmpty()) {
-            var node = stack.pop();
+            int node = stack.pop();
             if (vis[node] == 0) {
                 dfs2(node, vis, transposeGraph);
                 sccsList.add(scc);
@@ -120,7 +135,12 @@ public void findStronglyConnectedComponents(int v, List<List<Integer>> transpose
         }
     }
 
-    // Dfs to store the nodes in order of lowest finish time
+    /**
+     * Performs DFS on the original graph and pushes nodes onto the stack in order of their finish time.
+     * @param node the current node being visited
+     * @param vis array to keep track of visited nodes
+     * @param list the adjacency list of the graph
+     */
     private void dfs(int node, int[] vis, List<List<Integer>> list) {
         vis[node] = 1;
         for (Integer neighbour : list.get(node)) {
@@ -131,7 +151,12 @@ private void dfs(int node, int[] vis, List<List<Integer>> list) {
         stack.push(node);
     }
 
-    // Dfs to find all the nodes of each strongly connected component
+    /**
+     * Performs DFS on the transposed graph to find the strongly connected components.
+     * @param node the current node being visited
+     * @param vis array to keep track of visited nodes
+     * @param list the adjacency list of the transposed graph
+     */
     private void dfs2(int node, int[] vis, List<List<Integer>> list) {
         vis[node] = 1;
         for (Integer neighbour : list.get(node)) {
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java
index c1e68acac2e6..53ed26dff26f 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.datastructures.graphs;
 
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -9,14 +9,13 @@
 
 public class KosarajuTest {
 
-    private Kosaraju kosaraju = new Kosaraju();
+    private final Kosaraju kosaraju = new Kosaraju();
 
     @Test
-    public void findStronglyConnectedComps() {
-        // Create a adjacency list of graph
-        var n = 8;
-        var adjList = new ArrayList<List<Integer>>(n);
-
+    public void testFindStronglyConnectedComponents() {
+        // Create a graph using adjacency list
+        int n = 8;
+        List<List<Integer>> adjList = new ArrayList<>(n);
         for (int i = 0; i < n; i++) {
             adjList.add(new ArrayList<>());
         }
@@ -36,24 +35,24 @@ public void findStronglyConnectedComps() {
         List<List<Integer>> expectedResult = new ArrayList<>();
         /*
             Expected result:
-            0, 1, 2
-            3
-            5, 4, 6
-            7
+            {0, 1, 2}
+            {3}
+            {5, 4, 6}
+            {7}
         */
         expectedResult.add(Arrays.asList(1, 2, 0));
-        expectedResult.add(Arrays.asList(3));
+        expectedResult.add(List.of(3));
         expectedResult.add(Arrays.asList(5, 6, 4));
-        expectedResult.add(Arrays.asList(7));
-        assertTrue(expectedResult.equals(actualResult));
+        expectedResult.add(List.of(7));
+
+        assertEquals(expectedResult, actualResult);
     }
 
     @Test
-    public void findStronglyConnectedCompsShouldGetSingleNodes() {
-        // Create a adjacency list of graph
-        var n = 8;
-        var adjList = new ArrayList<List<Integer>>(n);
-
+    public void testFindSingleNodeSCC() {
+        // Create a simple graph using adjacency list
+        int n = 8;
+        List<List<Integer>> adjList = new ArrayList<>(n);
         for (int i = 0; i < n; i++) {
             adjList.add(new ArrayList<>());
         }
@@ -71,9 +70,42 @@ public void findStronglyConnectedCompsShouldGetSingleNodes() {
         List<List<Integer>> expectedResult = new ArrayList<>();
         /*
             Expected result:
-            0, 1, 2, 3, 4, 5, 6, 7
+            {0, 1, 2, 3, 4, 5, 6, 7}
         */
         expectedResult.add(Arrays.asList(1, 2, 3, 4, 5, 6, 7, 0));
-        assertTrue(expectedResult.equals(actualResult));
+
+        assertEquals(expectedResult, actualResult);
+    }
+
+    @Test
+    public void testDisconnectedGraph() {
+        // Create a disconnected graph (two separate components)
+        int n = 5;
+        List<List<Integer>> adjList = new ArrayList<>(n);
+        for (int i = 0; i < n; i++) {
+            adjList.add(new ArrayList<>());
+        }
+
+        // Add edges for first component
+        adjList.get(0).add(1);
+        adjList.get(1).add(2);
+        adjList.get(2).add(0);
+
+        // Add edges for second component
+        adjList.get(3).add(4);
+        adjList.get(4).add(3);
+
+        List<List<Integer>> actualResult = kosaraju.kosaraju(n, adjList);
+
+        List<List<Integer>> expectedResult = new ArrayList<>();
+        /*
+            Expected result:
+            {0, 1, 2}
+            {3, 4}
+        */
+        expectedResult.add(Arrays.asList(4, 3));
+        expectedResult.add(Arrays.asList(1, 2, 0));
+
+        assertEquals(expectedResult, actualResult);
     }
 }

From 0feb41618872014f0809942ca1def0978eac1225 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 24 Oct 2024 11:11:55 +0530
Subject: [PATCH 0605/1338] Enhance docs, add tests in `Kruskal` (#5967)

---
 DIRECTORY.md                                  |   1 +
 .../datastructures/graphs/Kruskal.java        | 107 ++++++++---------
 .../datastructures/graphs/KruskalTest.java    | 112 ++++++++++++++++++
 3 files changed, 161 insertions(+), 59 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0539f0df1350..1def3e25c064 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -812,6 +812,7 @@
               * [JohnsonsAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java)
               * [KahnsAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithmTest.java)
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
+              * [KruskalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java)
               * [TarjansAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
               * [WelshPowellTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java)
             * hashmap
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java b/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
index eb5b65d5c0d4..25c4548daa7a 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
@@ -1,27 +1,34 @@
 package com.thealgorithms.datastructures.graphs;
 
-// Problem -> Connect all the edges with the minimum cost.
-// Possible Solution -> Kruskal Algorithm (KA), KA finds the minimum-spanning-tree, which means, the
-// group of edges with the minimum sum of their weights that connect the whole graph.
-// The graph needs to be connected, because if there are nodes impossible to reach, there are no
-// edges that could connect every node in the graph.
-// KA is a Greedy Algorithm, because edges are analysed based on their weights, that is why a
-// Priority Queue is used, to take first those less weighted.
-// This implementations below has some changes compared to conventional ones, but they are explained
-// all along the code.
 import java.util.Comparator;
 import java.util.HashSet;
 import java.util.PriorityQueue;
 
+/**
+ * The Kruskal class implements Kruskal's Algorithm to find the Minimum Spanning Tree (MST)
+ * of a connected, undirected graph. The algorithm constructs the MST by selecting edges
+ * with the least weight, ensuring no cycles are formed, and using union-find to track the
+ * connected components.
+ *
+ * <p><strong>Key Features:</strong></p>
+ * <ul>
+ *   <li>The graph is represented using an adjacency list, where each node points to a set of edges.</li>
+ *   <li>Each edge is processed in ascending order of weight using a priority queue.</li>
+ *   <li>The algorithm stops when all nodes are connected or no more edges are available.</li>
+ * </ul>
+ *
+ * <p><strong>Time Complexity:</strong> O(E log V), where E is the number of edges and V is the number of vertices.</p>
+ */
 public class Kruskal {
 
-    // Complexity: O(E log V) time, where E is the number of edges in the graph and V is the number
-    // of vertices
-    private static class Edge {
+    /**
+     * Represents an edge in the graph with a source, destination, and weight.
+     */
+    static class Edge {
 
-        private int from;
-        private int to;
-        private int weight;
+        int from;
+        int to;
+        int weight;
 
         Edge(int from, int to, int weight) {
             this.from = from;
@@ -30,51 +37,30 @@ private static class Edge {
         }
     }
 
-    private static void addEdge(HashSet<Edge>[] graph, int from, int to, int weight) {
+    /**
+     * Adds an edge to the graph.
+     *
+     * @param graph the adjacency list representing the graph
+     * @param from the source vertex of the edge
+     * @param to the destination vertex of the edge
+     * @param weight the weight of the edge
+     */
+    static void addEdge(HashSet<Edge>[] graph, int from, int to, int weight) {
         graph[from].add(new Edge(from, to, weight));
     }
 
-    public static void main(String[] args) {
-        HashSet<Edge>[] graph = new HashSet[7];
-        for (int i = 0; i < graph.length; i++) {
-            graph[i] = new HashSet<>();
-        }
-        addEdge(graph, 0, 1, 2);
-        addEdge(graph, 0, 2, 3);
-        addEdge(graph, 0, 3, 3);
-        addEdge(graph, 1, 2, 4);
-        addEdge(graph, 2, 3, 5);
-        addEdge(graph, 1, 4, 3);
-        addEdge(graph, 2, 4, 1);
-        addEdge(graph, 3, 5, 7);
-        addEdge(graph, 4, 5, 8);
-        addEdge(graph, 5, 6, 9);
-
-        System.out.println("Initial Graph: ");
-        for (int i = 0; i < graph.length; i++) {
-            for (Edge edge : graph[i]) {
-                System.out.println(i + " <-- weight " + edge.weight + " --> " + edge.to);
-            }
-        }
-
-        Kruskal k = new Kruskal();
-        HashSet<Edge>[] solGraph = k.kruskal(graph);
-
-        System.out.println("\nMinimal Graph: ");
-        for (int i = 0; i < solGraph.length; i++) {
-            for (Edge edge : solGraph[i]) {
-                System.out.println(i + " <-- weight " + edge.weight + " --> " + edge.to);
-            }
-        }
-    }
-
+    /**
+     * Kruskal's algorithm to find the Minimum Spanning Tree (MST) of a graph.
+     *
+     * @param graph the adjacency list representing the input graph
+     * @return the adjacency list representing the MST
+     */
     public HashSet<Edge>[] kruskal(HashSet<Edge>[] graph) {
         int nodes = graph.length;
-        int[] captain = new int[nodes];
-        // captain of i, stores the set with all the connected nodes to i
+        int[] captain = new int[nodes]; // Stores the "leader" of each node's connected component
         HashSet<Integer>[] connectedGroups = new HashSet[nodes];
         HashSet<Edge>[] minGraph = new HashSet[nodes];
-        PriorityQueue<Edge> edges = new PriorityQueue<>((Comparator.comparingInt(edge -> edge.weight)));
+        PriorityQueue<Edge> edges = new PriorityQueue<>(Comparator.comparingInt(edge -> edge.weight));
         for (int i = 0; i < nodes; i++) {
             minGraph[i] = new HashSet<>();
             connectedGroups[i] = new HashSet<>();
@@ -83,18 +69,21 @@ public HashSet<Edge>[] kruskal(HashSet<Edge>[] graph) {
             edges.addAll(graph[i]);
         }
         int connectedElements = 0;
-        // as soon as two sets merge all the elements, the algorithm must stop
         while (connectedElements != nodes && !edges.isEmpty()) {
             Edge edge = edges.poll();
-            // This if avoids cycles
+
+            // Avoid forming cycles by checking if the nodes belong to different connected components
             if (!connectedGroups[captain[edge.from]].contains(edge.to) && !connectedGroups[captain[edge.to]].contains(edge.from)) {
-                // merge sets of the captains of each point connected by the edge
+                // Merge the two sets of nodes connected by the edge
                 connectedGroups[captain[edge.from]].addAll(connectedGroups[captain[edge.to]]);
-                // update captains of the elements merged
+
+                // Update the captain for each merged node
                 connectedGroups[captain[edge.from]].forEach(i -> captain[i] = captain[edge.from]);
-                // add Edge to minimal graph
+
+                // Add the edge to the resulting MST graph
                 addEdge(minGraph, edge.from, edge.to, edge.weight);
-                // count how many elements have been merged
+
+                // Update the count of connected nodes
                 connectedElements = connectedGroups[captain[edge.from]].size();
             }
         }
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java
new file mode 100644
index 000000000000..b18f161ef1a6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java
@@ -0,0 +1,112 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class KruskalTest {
+
+    private Kruskal kruskal;
+    private HashSet<Kruskal.Edge>[] graph;
+
+    @BeforeEach
+    public void setUp() {
+        kruskal = new Kruskal();
+        int n = 7;
+        graph = new HashSet[n];
+        for (int i = 0; i < n; i++) {
+            graph[i] = new HashSet<>();
+        }
+
+        // Add edges to the graph
+        Kruskal.addEdge(graph, 0, 1, 2);
+        Kruskal.addEdge(graph, 0, 2, 3);
+        Kruskal.addEdge(graph, 0, 3, 3);
+        Kruskal.addEdge(graph, 1, 2, 4);
+        Kruskal.addEdge(graph, 2, 3, 5);
+        Kruskal.addEdge(graph, 1, 4, 3);
+        Kruskal.addEdge(graph, 2, 4, 1);
+        Kruskal.addEdge(graph, 3, 5, 7);
+        Kruskal.addEdge(graph, 4, 5, 8);
+        Kruskal.addEdge(graph, 5, 6, 9);
+    }
+
+    @Test
+    public void testKruskal() {
+        int n = 6;
+        HashSet<Kruskal.Edge>[] graph = new HashSet[n];
+
+        for (int i = 0; i < n; i++) {
+            graph[i] = new HashSet<>();
+        }
+
+        Kruskal.addEdge(graph, 0, 1, 4);
+        Kruskal.addEdge(graph, 0, 2, 2);
+        Kruskal.addEdge(graph, 1, 2, 1);
+        Kruskal.addEdge(graph, 1, 3, 5);
+        Kruskal.addEdge(graph, 2, 3, 8);
+        Kruskal.addEdge(graph, 2, 4, 10);
+        Kruskal.addEdge(graph, 3, 4, 2);
+        Kruskal.addEdge(graph, 3, 5, 6);
+        Kruskal.addEdge(graph, 4, 5, 3);
+
+        HashSet<Kruskal.Edge>[] result = kruskal.kruskal(graph);
+
+        List<List<Integer>> actualEdges = new ArrayList<>();
+        for (HashSet<Kruskal.Edge> edges : result) {
+            for (Kruskal.Edge edge : edges) {
+                actualEdges.add(Arrays.asList(edge.from, edge.to, edge.weight));
+            }
+        }
+
+        List<List<Integer>> expectedEdges = Arrays.asList(Arrays.asList(1, 2, 1), Arrays.asList(0, 2, 2), Arrays.asList(3, 4, 2), Arrays.asList(4, 5, 3), Arrays.asList(1, 3, 5));
+
+        assertTrue(actualEdges.containsAll(expectedEdges) && expectedEdges.containsAll(actualEdges));
+    }
+
+    @Test
+    public void testEmptyGraph() {
+        HashSet<Kruskal.Edge>[] emptyGraph = new HashSet[0];
+        HashSet<Kruskal.Edge>[] result = kruskal.kruskal(emptyGraph);
+        assertEquals(0, result.length);
+    }
+
+    @Test
+    public void testSingleNodeGraph() {
+        HashSet<Kruskal.Edge>[] singleNodeGraph = new HashSet[1];
+        singleNodeGraph[0] = new HashSet<>();
+        HashSet<Kruskal.Edge>[] result = kruskal.kruskal(singleNodeGraph);
+        assertTrue(result[0].isEmpty());
+    }
+
+    @Test
+    public void testGraphWithDisconnectedNodes() {
+        int n = 5;
+        HashSet<Kruskal.Edge>[] disconnectedGraph = new HashSet[n];
+        for (int i = 0; i < n; i++) {
+            disconnectedGraph[i] = new HashSet<>();
+        }
+
+        Kruskal.addEdge(disconnectedGraph, 0, 1, 2);
+        Kruskal.addEdge(disconnectedGraph, 2, 3, 4);
+
+        HashSet<Kruskal.Edge>[] result = kruskal.kruskal(disconnectedGraph);
+
+        List<List<Integer>> actualEdges = new ArrayList<>();
+        for (HashSet<Kruskal.Edge> edges : result) {
+            for (Kruskal.Edge edge : edges) {
+                actualEdges.add(Arrays.asList(edge.from, edge.to, edge.weight));
+            }
+        }
+
+        List<List<Integer>> expectedEdges = Arrays.asList(Arrays.asList(0, 1, 2), Arrays.asList(2, 3, 4));
+
+        assertTrue(actualEdges.containsAll(expectedEdges) && expectedEdges.containsAll(actualEdges));
+    }
+}

From 5246f635797194f5f0d7ac93af61099a5764fa4f Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 24 Oct 2024 11:20:12 +0530
Subject: [PATCH 0606/1338] Enhance docs, remove `main`. add more tests (#5925)

---
 .../conversions/IntegerToRoman.java           | 96 +++++++++----------
 .../conversions/IntegerToRomanTest.java       | 25 +++++
 2 files changed, 73 insertions(+), 48 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java b/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
index 9c031df9504d..fec437668fe6 100644
--- a/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
+++ b/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java
@@ -1,68 +1,68 @@
 package com.thealgorithms.conversions;
 
 /**
- * Converting Integers into Roman Numerals
+ * A utility class to convert integers into Roman numerals.
  *
- * <p>
- * ('I', 1); ('IV',4); ('V', 5); ('IX',9); ('X', 10); ('XL',40); ('L', 50);
- * ('XC',90); ('C', 100); ('D', 500); ('M', 1000);
+ * <p>Roman numerals follow these rules:
+ * <ul>
+ *   <li>I = 1</li>
+ *   <li>IV = 4</li>
+ *   <li>V = 5</li>
+ *   <li>IX = 9</li>
+ *   <li>X = 10</li>
+ *   <li>XL = 40</li>
+ *   <li>L = 50</li>
+ *   <li>XC = 90</li>
+ *   <li>C = 100</li>
+ *   <li>D = 500</li>
+ *   <li>M = 1000</li>
+ * </ul>
+ *
+ * <p>Conversion is based on repeatedly subtracting the largest possible Roman numeral value
+ * from the input number until it reaches zero. For example, 1994 is converted as:
+ * <pre>
+ *   1994 -> MCMXCIV (1000 + 900 + 90 + 4)
+ * </pre>
  */
 public final class IntegerToRoman {
+
+    // Array of Roman numeral values in descending order
+    private static final int[] ALL_ROMAN_NUMBERS_IN_ARABIC = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
+
+    // Corresponding Roman numeral symbols
+    private static final String[] ALL_ROMAN_NUMBERS = {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};
+
     private IntegerToRoman() {
     }
 
-    private static final int[] ALL_ROMAN_NUMBERS_IN_ARABIC = new int[] {
-        1000,
-        900,
-        500,
-        400,
-        100,
-        90,
-        50,
-        40,
-        10,
-        9,
-        5,
-        4,
-        1,
-    };
-    private static final String[] ALL_ROMAN_NUMBERS = new String[] {
-        "M",
-        "CM",
-        "D",
-        "CD",
-        "C",
-        "XC",
-        "L",
-        "XL",
-        "X",
-        "IX",
-        "V",
-        "IV",
-        "I",
-    };
-
-    // Value must be > 0
+    /**
+     * Converts an integer to its Roman numeral representation.
+     * Steps:
+     * <ol>
+     *     <li>Iterate over the Roman numeral values in descending order</li>
+     *     <li>Calculate how many times a numeral fits</li>
+     *     <li>Append the corresponding symbol</li>
+     *     <li>Subtract the value from the number</li>
+     *     <li>Repeat until the number is zero</li>
+     *     <li>Return the Roman numeral representation</li>
+     * </ol>
+     *
+     * @param num the integer value to convert (must be greater than 0)
+     * @return the Roman numeral representation of the input integer
+     *         or an empty string if the input is non-positive
+     */
     public static String integerToRoman(int num) {
         if (num <= 0) {
             return "";
         }
 
         StringBuilder builder = new StringBuilder();
-
-        for (int a = 0; a < ALL_ROMAN_NUMBERS_IN_ARABIC.length; a++) {
-            int times = num / ALL_ROMAN_NUMBERS_IN_ARABIC[a];
-            for (int b = 0; b < times; b++) {
-                builder.append(ALL_ROMAN_NUMBERS[a]);
-            }
-
-            num -= times * ALL_ROMAN_NUMBERS_IN_ARABIC[a];
+        for (int i = 0; i < ALL_ROMAN_NUMBERS_IN_ARABIC.length; i++) {
+            int times = num / ALL_ROMAN_NUMBERS_IN_ARABIC[i];
+            builder.append(ALL_ROMAN_NUMBERS[i].repeat(Math.max(0, times)));
+            num -= times * ALL_ROMAN_NUMBERS_IN_ARABIC[i];
         }
 
         return builder.toString();
     }
-
-    public static void main(String[] args) {
-        System.out.println(IntegerToRoman.integerToRoman(2131));
-    }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java b/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java
index 04768d034b93..181cad930282 100644
--- a/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java
+++ b/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java
@@ -10,5 +10,30 @@ public class IntegerToRomanTest {
     public void testIntegerToRoman() {
         assertEquals("MCMXCIV", IntegerToRoman.integerToRoman(1994));
         assertEquals("LVIII", IntegerToRoman.integerToRoman(58));
+        assertEquals("IV", IntegerToRoman.integerToRoman(4));
+        assertEquals("IX", IntegerToRoman.integerToRoman(9));
+        assertEquals("MMM", IntegerToRoman.integerToRoman(3000));
+    }
+
+    @Test
+    public void testSmallNumbers() {
+        assertEquals("I", IntegerToRoman.integerToRoman(1));
+        assertEquals("II", IntegerToRoman.integerToRoman(2));
+        assertEquals("III", IntegerToRoman.integerToRoman(3));
+    }
+
+    @Test
+    public void testRoundNumbers() {
+        assertEquals("X", IntegerToRoman.integerToRoman(10));
+        assertEquals("L", IntegerToRoman.integerToRoman(50));
+        assertEquals("C", IntegerToRoman.integerToRoman(100));
+        assertEquals("D", IntegerToRoman.integerToRoman(500));
+        assertEquals("M", IntegerToRoman.integerToRoman(1000));
+    }
+
+    @Test
+    public void testEdgeCases() {
+        assertEquals("", IntegerToRoman.integerToRoman(0)); // Non-positive number case
+        assertEquals("", IntegerToRoman.integerToRoman(-5)); // Negative number case
     }
 }

From 6f489e570486f77466406fca4820aec74ae513de Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 25 Oct 2024 19:50:59 +0530
Subject: [PATCH 0607/1338] Enhance docs, add tests in `QuickSortLinkedList`
 (#5998)

---
 .../lists/QuickSortLinkedList.java            | 43 +++++++-----
 .../lists/QuickSortLinkedListTest.java        | 66 ++++++++++++++-----
 2 files changed, 76 insertions(+), 33 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java
index 36b6e9c62cbe..08fe674b47f4 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java
@@ -104,36 +104,52 @@
 
 public class QuickSortLinkedList {
 
-    private SinglyLinkedList list = null; // Linked list
-    private Node head = null; // head of the list
-    // Counstructor
+    private final SinglyLinkedList list; // The linked list to be sorted
+    private Node head; // Head of the list
+
+    /**
+     * Constructor that initializes the QuickSortLinkedList with a given linked list.
+     *
+     * @param list The singly linked list to be sorted
+     */
     public QuickSortLinkedList(SinglyLinkedList list) {
         this.list = list;
         this.head = list.getHead();
     }
 
-    // Function to sort a linked list using the Quick Sort algorithm
+    /**
+     * Sorts the linked list using the QuickSort algorithm.
+     * The sorted list replaces the original list within the SinglyLinkedList instance.
+     */
     public void sortList() {
         head = sortList(head);
         list.setHead(head);
     }
-    // helper function to apply QuickSort to the stored list
-    public Node sortList(Node head) {
+
+    /**
+     * Recursively sorts a linked list by partitioning it around a pivot element.
+     *
+     * <p>Each recursive call selects a pivot, partitions the list into elements less
+     * than the pivot and elements greater than or equal to the pivot, then combines
+     * the sorted sublists around the pivot.</p>
+     *
+     * @param head The head node of the list to sort
+     * @return The head node of the sorted linked list
+     */
+    private Node sortList(Node head) {
         if (head == null || head.next == null) {
             return head;
         }
 
-        // Choose the first element as the pivot
         Node pivot = head;
         head = head.next;
         pivot.next = null;
 
-        Node lessHead = new Node(); // stores the nodes cantaining data less than pivot node
-        Node lessTail = lessHead; // tail of lessHead
-        Node greaterHead = new Node(); // stores the nodes cantaining data greater than pivot node
-        Node greaterTail = greaterHead; // tail of greaterHead
+        Node lessHead = new Node();
+        Node lessTail = lessHead;
+        Node greaterHead = new Node();
+        Node greaterTail = greaterHead;
 
-        // Partition the list around the pivot
         while (head != null) {
             if (head.value < pivot.value) {
                 lessTail.next = head;
@@ -145,15 +161,12 @@ public Node sortList(Node head) {
             head = head.next;
         }
 
-        // Seperating lessHead and greaterHead to form two seperate linkedList
         lessTail.next = null;
         greaterTail.next = null;
 
-        // Recursively sort the sublists
         Node sortedLess = sortList(lessHead.next);
         Node sortedGreater = sortList(greaterHead.next);
 
-        // Combine the sorted sublists and pivot
         if (sortedLess == null) {
             pivot.next = sortedGreater;
             return pivot;
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
index 91e2ba5d43ce..4e86f317c2e8 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java
@@ -4,8 +4,9 @@
 import static org.junit.jupiter.api.Assertions.assertNull;
 
 import org.junit.jupiter.api.Test;
+
 /**
- * Test cases for QuickSortLinkedList
+ * Test cases for QuickSortLinkedList.
  * Author: Prabhat-Kumar-42
  * GitHub: https://github.com/Prabhat-Kumar-42
  */
@@ -16,9 +17,8 @@ public void testSortEmptyList() {
         SinglyLinkedList emptyList = new SinglyLinkedList();
         QuickSortLinkedList sorter = new QuickSortLinkedList(emptyList);
 
-        // Test case: Sorting an empty list should result in an empty list
         sorter.sortList();
-        assertNull(emptyList.getHead());
+        assertNull(emptyList.getHead(), "Sorted empty list should have no elements.");
     }
 
     @Test
@@ -27,10 +27,51 @@ public void testSortSingleNodeList() {
         singleNodeList.insert(5);
         QuickSortLinkedList sorter = new QuickSortLinkedList(singleNodeList);
 
-        // Test case: Sorting a list with a single node should result in the same list
         sorter.sortList();
-        assertEquals(5, singleNodeList.getHead().value);
-        assertNull(singleNodeList.getHead().next);
+        assertEquals(5, singleNodeList.getHead().value, "Single node list should remain unchanged after sorting.");
+        assertNull(singleNodeList.getHead().next, "Single node should not have a next node.");
+    }
+
+    @Test
+    public void testSortAlreadySorted() {
+        SinglyLinkedList sortedList = new SinglyLinkedList();
+        sortedList.insert(1);
+        sortedList.insert(2);
+        sortedList.insert(3);
+        sortedList.insert(4);
+        sortedList.insert(5);
+        QuickSortLinkedList sorter = new QuickSortLinkedList(sortedList);
+
+        sorter.sortList();
+        assertEquals("1->2->3->4->5", sortedList.toString(), "Already sorted list should remain unchanged.");
+    }
+
+    @Test
+    public void testSortReverseOrderedList() {
+        SinglyLinkedList reverseList = new SinglyLinkedList();
+        reverseList.insert(5);
+        reverseList.insert(4);
+        reverseList.insert(3);
+        reverseList.insert(2);
+        reverseList.insert(1);
+        QuickSortLinkedList sorter = new QuickSortLinkedList(reverseList);
+
+        sorter.sortList();
+        assertEquals("1->2->3->4->5", reverseList.toString(), "Reverse ordered list should be sorted in ascending order.");
+    }
+
+    @Test
+    public void testSortWithDuplicates() {
+        SinglyLinkedList listWithDuplicates = new SinglyLinkedList();
+        listWithDuplicates.insert(3);
+        listWithDuplicates.insert(1);
+        listWithDuplicates.insert(3);
+        listWithDuplicates.insert(2);
+        listWithDuplicates.insert(2);
+        QuickSortLinkedList sorter = new QuickSortLinkedList(listWithDuplicates);
+
+        sorter.sortList();
+        assertEquals("1->2->2->3->3", listWithDuplicates.toString(), "List with duplicates should be sorted correctly.");
     }
 
     @Test
@@ -48,18 +89,7 @@ public void testSortMultipleElementsList() {
         list.insert(6);
         QuickSortLinkedList sorter = new QuickSortLinkedList(list);
 
-        // Test case: Sorting a list with multiple elements
         sorter.sortList();
-        assertEquals(1, list.getHead().value);
-        assertEquals(2, list.getHead().next.value);
-        assertEquals(3, list.getHead().next.next.value);
-        assertEquals(4, list.getHead().next.next.next.value);
-        assertEquals(5, list.getHead().next.next.next.next.value);
-        assertEquals(6, list.getHead().next.next.next.next.next.value);
-        assertEquals(7, list.getHead().next.next.next.next.next.next.value);
-        assertEquals(8, list.getHead().next.next.next.next.next.next.next.value);
-        assertEquals(9, list.getHead().next.next.next.next.next.next.next.next.value);
-        assertEquals(10, list.getHead().next.next.next.next.next.next.next.next.next.value);
-        assertNull(list.getHead().next.next.next.next.next.next.next.next.next.next);
+        assertEquals("1->2->3->4->5->6->7->8->9->10", list.toString(), "List should be sorted in ascending order.");
     }
 }

From fed2d4b5efb057b1f35135651d290bfcea9bc3e4 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 25 Oct 2024 19:55:55 +0530
Subject: [PATCH 0608/1338] =?UTF-8?q?Enhance=20docs,=20remove=20`main`,=20?=
 =?UTF-8?q?add=20tests=20in=20`MergeSortedSingl=E2=80=A6=20(#5997)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 DIRECTORY.md                                  |  1 +
 .../lists/MergeSortedSinglyLinkedList.java    | 64 ++++++++-----
 .../MergeSortedSinglyLinkedListTest.java      | 90 +++++++++++++++++++
 3 files changed, 131 insertions(+), 24 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 1def3e25c064..4ceaefd6ea02 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -830,6 +830,7 @@
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
               * [CreateAndDetectLoopTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java)
+              * [MergeSortedSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java)
               * [QuickSortLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java)
               * [ReverseKGroupTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java)
               * [RotateSinglyLinkedListsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java
index 2bee945c9db6..a16b202c4505 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java
@@ -1,31 +1,49 @@
 package com.thealgorithms.datastructures.lists;
 
+/**
+ * Utility class for merging two sorted singly linked lists.
+ *
+ * <p>This class extends the {@link SinglyLinkedList} class to support the merging of two sorted linked lists.
+ * It provides a static method, `merge`, that takes two sorted singly linked lists, merges them into a single sorted linked list,
+ * and returns the result.</p>
+ *
+ * <p>Example usage:</p>
+ * <pre>
+ * SinglyLinkedList listA = new SinglyLinkedList();
+ * SinglyLinkedList listB = new SinglyLinkedList();
+ * for (int i = 2; i <= 10; i += 2) {
+ *     listA.insert(i);   // listA: 2->4->6->8->10
+ *     listB.insert(i - 1); // listB: 1->3->5->7->9
+ * }
+ * SinglyLinkedList mergedList = MergeSortedSinglyLinkedList.merge(listA, listB);
+ * System.out.println(mergedList); // Output: 1->2->3->4->5->6->7->8->9->10
+ * </pre>
+ *
+ * <p>The `merge` method assumes that both input lists are already sorted in ascending order.
+ * It returns a new singly linked list that contains all elements from both lists in sorted order.</p>
+ *
+ * @see SinglyLinkedList
+ */
 public class MergeSortedSinglyLinkedList extends SinglyLinkedList {
 
-    public static void main(String[] args) {
-        SinglyLinkedList listA = new SinglyLinkedList();
-        SinglyLinkedList listB = new SinglyLinkedList();
-
-        for (int i = 2; i <= 10; i += 2) {
-            listA.insert(i);
-            listB.insert(i - 1);
-        }
-        assert listA.toString().equals("2->4->6->8->10");
-        assert listB.toString().equals("1->3->5->7->9");
-        assert merge(listA, listB).toString().equals("1->2->3->4->5->6->7->8->9->10");
-    }
-
     /**
-     * Merge two sorted SingleLinkedList
+     * Merges two sorted singly linked lists into a single sorted singly linked list.
+     *
+     * <p>This method does not modify the input lists; instead, it creates a new merged linked list
+     * containing all elements from both lists in sorted order.</p>
      *
-     * @param listA the first sorted list
-     * @param listB the second sored list
-     * @return merged sorted list
+     * @param listA The first sorted singly linked list.
+     * @param listB The second sorted singly linked list.
+     * @return A new singly linked list containing all elements from both lists in sorted order.
+     * @throws NullPointerException if either input list is null.
      */
     public static SinglyLinkedList merge(SinglyLinkedList listA, SinglyLinkedList listB) {
+        if (listA == null || listB == null) {
+            throw new NullPointerException("Input lists must not be null.");
+        }
+
         Node headA = listA.getHead();
         Node headB = listB.getHead();
-
         int size = listA.size() + listB.size();
 
         Node head = new Node();
@@ -40,12 +58,10 @@ public static SinglyLinkedList merge(SinglyLinkedList listA, SinglyLinkedList li
             }
             tail = tail.next;
         }
-        if (headA == null) {
-            tail.next = headB;
-        }
-        if (headB == null) {
-            tail.next = headA;
-        }
+
+        // Attach remaining nodes
+        tail.next = (headA == null) ? headB : headA;
+
         return new SinglyLinkedList(head.next, size);
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java
new file mode 100644
index 000000000000..b6b785f43711
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java
@@ -0,0 +1,90 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class MergeSortedSinglyLinkedListTest {
+
+    @Test
+    void testMergeTwoSortedLists() {
+        SinglyLinkedList listA = new SinglyLinkedList();
+        SinglyLinkedList listB = new SinglyLinkedList();
+
+        for (int i = 2; i <= 10; i += 2) {
+            listA.insert(i);
+            listB.insert(i - 1);
+        }
+
+        SinglyLinkedList mergedList = MergeSortedSinglyLinkedList.merge(listA, listB);
+        assertEquals("1->2->3->4->5->6->7->8->9->10", mergedList.toString(), "Merged list should contain all elements in sorted order.");
+    }
+
+    @Test
+    void testMergeWithEmptyListA() {
+        SinglyLinkedList listA = new SinglyLinkedList(); // Empty listA
+        SinglyLinkedList listB = new SinglyLinkedList();
+        listB.insert(1);
+        listB.insert(3);
+        listB.insert(5);
+
+        SinglyLinkedList mergedList = MergeSortedSinglyLinkedList.merge(listA, listB);
+        assertEquals("1->3->5", mergedList.toString(), "Merged list should match listB when listA is empty.");
+    }
+
+    @Test
+    void testMergeWithEmptyListB() {
+        SinglyLinkedList listA = new SinglyLinkedList();
+        SinglyLinkedList listB = new SinglyLinkedList(); // Empty listB
+        listA.insert(2);
+        listA.insert(4);
+        listA.insert(6);
+
+        SinglyLinkedList mergedList = MergeSortedSinglyLinkedList.merge(listA, listB);
+        assertEquals("2->4->6", mergedList.toString(), "Merged list should match listA when listB is empty.");
+    }
+
+    @Test
+    void testMergeWithBothEmptyLists() {
+        SinglyLinkedList listA = new SinglyLinkedList(); // Empty listA
+        SinglyLinkedList listB = new SinglyLinkedList(); // Empty listB
+
+        SinglyLinkedList mergedList = MergeSortedSinglyLinkedList.merge(listA, listB);
+        assertEquals("", mergedList.toString(), "Merged list should be empty when both input lists are empty.");
+    }
+
+    @Test
+    void testMergeWithDuplicateValues() {
+        SinglyLinkedList listA = new SinglyLinkedList();
+        SinglyLinkedList listB = new SinglyLinkedList();
+
+        listA.insert(1);
+        listA.insert(3);
+        listA.insert(5);
+        listB.insert(1);
+        listB.insert(4);
+        listB.insert(5);
+
+        SinglyLinkedList mergedList = MergeSortedSinglyLinkedList.merge(listA, listB);
+        assertEquals("1->1->3->4->5->5", mergedList.toString(), "Merged list should include duplicate values in sorted order.");
+    }
+
+    @Test
+    void testMergeThrowsExceptionOnNullInput() {
+        SinglyLinkedList listA = null;
+        SinglyLinkedList listB = new SinglyLinkedList();
+        listB.insert(1);
+        listB.insert(2);
+
+        SinglyLinkedList finalListA = listA;
+        SinglyLinkedList finalListB = listB;
+        assertThrows(NullPointerException.class, () -> MergeSortedSinglyLinkedList.merge(finalListA, finalListB), "Should throw NullPointerException if listA is null.");
+
+        listA = new SinglyLinkedList();
+        listB = null;
+        SinglyLinkedList finalListA1 = listA;
+        SinglyLinkedList finalListB1 = listB;
+        assertThrows(NullPointerException.class, () -> MergeSortedSinglyLinkedList.merge(finalListA1, finalListB1), "Should throw NullPointerException if listB is null.");
+    }
+}

From c8e9e748b2bcb2e7fd430cd207dabdda39fa1800 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 25 Oct 2024 20:03:40 +0530
Subject: [PATCH 0609/1338] =?UTF-8?q?Enhance=20docs,=20remove=20`main`,=20?=
 =?UTF-8?q?add=20tests=20in=20`MergeSortedArray=E2=80=A6=20(#5996)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 DIRECTORY.md                                  |  1 +
 .../lists/MergeSortedArrayList.java           | 67 +++++++------
 .../lists/MergeSortedArrayListTest.java       | 99 +++++++++++++++++++
 3 files changed, 136 insertions(+), 31 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 4ceaefd6ea02..95805ff411eb 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -830,6 +830,7 @@
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
               * [CreateAndDetectLoopTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java)
+              * [MergeSortedArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java)
               * [MergeSortedSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java)
               * [QuickSortLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java)
               * [ReverseKGroupTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java b/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java
index e315c4236338..09eb854c8dc2 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java
@@ -1,49 +1,55 @@
 package com.thealgorithms.datastructures.lists;
 
-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 
 /**
+ * Utility class for merging two sorted ArrayLists of integers into a single sorted collection.
+ *
+ * <p>This class provides a static `merge` method to combine two pre-sorted lists of integers into a
+ * single sorted list. It does so without modifying the input lists by adding elements from both lists in sorted order
+ * into the result list.</p>
+ *
+ * <p>Example usage:</p>
+ * <pre>
+ * List<Integer> listA = Arrays.asList(1, 3, 5, 7, 9);
+ * List<Integer> listB = Arrays.asList(2, 4, 6, 8, 10);
+ * List<Integer> result = new ArrayList<>();
+ * MergeSortedArrayList.merge(listA, listB, result);
+ * </pre>
+ *
+ * <p>The resulting `result` list will be [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].</p>
+ *
+ * <p>Note: This class cannot be instantiated as it is designed to be used only with its static `merge` method.</p>
+ *
+ * <p>This implementation assumes the input lists are already sorted in ascending order.</p>
+ *
  * @author https://github.com/shellhub
+ * @see List
  */
 public final class MergeSortedArrayList {
-    private MergeSortedArrayList() {
-    }
-
-    public static void main(String[] args) {
-        List<Integer> listA = new ArrayList<>();
-        List<Integer> listB = new ArrayList<>();
-        List<Integer> listC = new ArrayList<>();
-
-        /* init ListA and List B */
-        for (int i = 1; i <= 10; i += 2) {
-            listA.add(i);
-            /* listA: [1, 3, 5, 7, 9]  */
-            listB.add(i + 1);
-            /* listB: [2, 4, 6, 8, 10] */
-        }
-
-        /* merge listA and listB to listC */
-        merge(listA, listB, listC);
 
-        System.out.println("listA: " + listA);
-        System.out.println("listB: " + listB);
-        System.out.println("listC: " + listC);
+    private MergeSortedArrayList() {
     }
 
     /**
-     * merge two sorted ArrayList
+     * Merges two sorted lists of integers into a single sorted collection.
+     *
+     * <p>This method does not alter the original lists (`listA` and `listB`). Instead, it inserts elements from both
+     * lists into `listC` in a way that maintains ascending order.</p>
      *
-     * @param listA the first list to merge
-     * @param listB the second list to merge
-     * @param listC the result list after merging
+     * @param listA The first sorted list of integers.
+     * @param listB The second sorted list of integers.
+     * @param listC The collection to hold the merged result, maintaining sorted order.
+     * @throws NullPointerException if any of the input lists or result collection is null.
      */
     public static void merge(List<Integer> listA, List<Integer> listB, Collection<Integer> listC) {
+        if (listA == null || listB == null || listC == null) {
+            throw new NullPointerException("Input lists and result collection must not be null.");
+        }
+
         int pa = 0;
-        /* the index of listA */
         int pb = 0;
-        /* the index of listB */
 
         while (pa < listA.size() && pb < listB.size()) {
             if (listA.get(pa) <= listB.get(pb)) {
@@ -53,12 +59,11 @@ public static void merge(List<Integer> listA, List<Integer> listB, Collection<In
             }
         }
 
-        /* copy left element of listA to listC */
+        // Add remaining elements from listA, if any
         while (pa < listA.size()) {
             listC.add(listA.get(pa++));
         }
-
-        /* copy left element of listB to listC */
+        // Add remaining elements from listB, if any
         while (pb < listB.size()) {
             listC.add(listB.get(pb++));
         }
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java
new file mode 100644
index 000000000000..5483bbcd0394
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java
@@ -0,0 +1,99 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class MergeSortedArrayListTest {
+
+    @Test
+    void testMergeTwoSortedLists() {
+        List<Integer> listA = Arrays.asList(1, 3, 5, 7, 9);
+        List<Integer> listB = Arrays.asList(2, 4, 6, 8, 10);
+        List<Integer> result = new ArrayList<>();
+
+        MergeSortedArrayList.merge(listA, listB, result);
+
+        List<Integer> expected = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+        assertEquals(expected, result, "Merged list should be sorted and contain all elements from both input lists.");
+    }
+
+    @Test
+    void testMergeWithEmptyList() {
+        List<Integer> listA = Arrays.asList(1, 2, 3);
+        List<Integer> listB = new ArrayList<>(); // Empty list
+        List<Integer> result = new ArrayList<>();
+
+        MergeSortedArrayList.merge(listA, listB, result);
+
+        List<Integer> expected = Arrays.asList(1, 2, 3);
+        assertEquals(expected, result, "Merged list should match listA when listB is empty.");
+    }
+
+    @Test
+    void testMergeWithBothEmptyLists() {
+        List<Integer> listA = new ArrayList<>(); // Empty list
+        List<Integer> listB = new ArrayList<>(); // Empty list
+        List<Integer> result = new ArrayList<>();
+
+        MergeSortedArrayList.merge(listA, listB, result);
+
+        assertTrue(result.isEmpty(), "Merged list should be empty when both input lists are empty.");
+    }
+
+    @Test
+    void testMergeWithDuplicateElements() {
+        List<Integer> listA = Arrays.asList(1, 2, 2, 3);
+        List<Integer> listB = Arrays.asList(2, 3, 4);
+        List<Integer> result = new ArrayList<>();
+
+        MergeSortedArrayList.merge(listA, listB, result);
+
+        List<Integer> expected = Arrays.asList(1, 2, 2, 2, 3, 3, 4);
+        assertEquals(expected, result, "Merged list should correctly handle and include duplicate elements.");
+    }
+
+    @Test
+    void testMergeWithNegativeAndPositiveNumbers() {
+        List<Integer> listA = Arrays.asList(-3, -1, 2);
+        List<Integer> listB = Arrays.asList(-2, 0, 3);
+        List<Integer> result = new ArrayList<>();
+
+        MergeSortedArrayList.merge(listA, listB, result);
+
+        List<Integer> expected = Arrays.asList(-3, -2, -1, 0, 2, 3);
+        assertEquals(expected, result, "Merged list should correctly handle negative and positive numbers.");
+    }
+
+    @Test
+    void testMergeThrowsExceptionOnNullInput() {
+        List<Integer> listA = null;
+        List<Integer> listB = Arrays.asList(1, 2, 3);
+        List<Integer> result = new ArrayList<>();
+
+        List<Integer> finalListB = listB;
+        List<Integer> finalListA = listA;
+        List<Integer> finalResult = result;
+        assertThrows(NullPointerException.class, () -> MergeSortedArrayList.merge(finalListA, finalListB, finalResult), "Should throw NullPointerException if any input list is null.");
+
+        listA = Arrays.asList(1, 2, 3);
+        listB = null;
+        List<Integer> finalListA1 = listA;
+        List<Integer> finalListB1 = listB;
+        List<Integer> finalResult1 = result;
+        assertThrows(NullPointerException.class, () -> MergeSortedArrayList.merge(finalListA1, finalListB1, finalResult1), "Should throw NullPointerException if any input list is null.");
+
+        listA = Arrays.asList(1, 2, 3);
+        listB = Arrays.asList(4, 5, 6);
+        result = null;
+        List<Integer> finalListA2 = listA;
+        List<Integer> finalListB2 = listB;
+        List<Integer> finalResult2 = result;
+        assertThrows(NullPointerException.class, () -> MergeSortedArrayList.merge(finalListA2, finalListB2, finalResult2), "Should throw NullPointerException if the result collection is null.");
+    }
+}

From cd87dc38776da2721bbac71a969166573685e574 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 25 Oct 2024 20:09:17 +0530
Subject: [PATCH 0610/1338] Enhance docs, add tests in `CreateAndDetectLoop`
 (#5993)

---
 .../lists/CreateAndDetectLoop.java            | 53 ++++++++++++-------
 .../lists/CreateAndDetectLoopTest.java        | 21 ++++++--
 2 files changed, 51 insertions(+), 23 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java b/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
index 49115b2d0f3d..3902d08bfd14 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java
@@ -1,11 +1,24 @@
 package com.thealgorithms.datastructures.lists;
 
+/**
+ * CreateAndDetectLoop provides utility methods for creating and detecting loops
+ * (cycles) in a singly linked list. Loops in a linked list are created by
+ * connecting the "next" pointer of one node to a previous node in the list,
+ * forming a cycle.
+ */
 public final class CreateAndDetectLoop {
 
-    // Node class representing a single node in the linked list
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
     private CreateAndDetectLoop() {
         throw new UnsupportedOperationException("Utility class");
     }
+
+    /**
+     * Node represents an individual element in the linked list, containing
+     * data and a reference to the next node.
+     */
     static final class Node {
         int data;
         Node next;
@@ -16,19 +29,16 @@ static final class Node {
         }
     }
 
-    // Method to create a loop between two specific positions in the linked list
-    /*
-     *  Test case that shows the Cycle(loop) in a LinkedList
-     *  Let's take this linked list:
-     *  1->2->3->4->5->6
-     *     \______/
-     *   In this linked list we can see there is a cycle.
-     *   we can create loop by calling createLoop function in main after creating LL
-     *   createLoop(head,2,5);
-     *  to detect there is loop or not we can call detectloop function in main
-     *  detectloop(head);
+    /**
+     * Creates a loop in a linked list by connecting the next pointer of a node
+     * at a specified starting position (position2) to another node at a specified
+     * destination position (position1). If either position is invalid, no loop
+     * will be created.
+     *
+     * @param head the head node of the linked list
+     * @param position1 the position in the list where the loop should end
+     * @param position2 the position in the list where the loop should start
      */
-
     static void createLoop(Node head, int position1, int position2) {
         if (position1 == 0 || position2 == 0) {
             return;
@@ -39,29 +49,32 @@ static void createLoop(Node head, int position1, int position2) {
 
         int count1 = 1;
         int count2 = 1;
-        // Traverse to find node at position1
+        // Traverse to the node at position1
         while (count1 < position1 && node1 != null) {
             node1 = node1.next;
             count1++;
         }
 
-        // Traverse to find node at position2
+        // Traverse to the node at position2
         while (count2 < position2 && node2 != null) {
             node2 = node2.next;
             count2++;
         }
 
-        // Create a loop by connecting node2's next to node1
+        // If both nodes are valid, create the loop
         if (node1 != null && node2 != null) {
             node2.next = node1;
         }
     }
-    // Method to detect a loop in the linked list
+
     /**
-     * Detects the presence of a loop in the linked list.
+     * Detects the presence of a loop in the linked list using Floyd's cycle-finding
+     * algorithm, also known as the "tortoise and hare" method.
      *
-     * @see <a href="https://en.wikipedia.org/wiki/Cycle_detection#Floyd's_tortoise_and_hare">Floyd's Cycle Detection Algorithm</a>
-     * @return true if loop exists else false
+     * @param head the head node of the linked list
+     * @return true if a loop is detected, false otherwise
+     * @see <a href="https://en.wikipedia.org/wiki/Cycle_detection#Floyd's_tortoise_and_hare">
+     *     Floyd's Cycle Detection Algorithm</a>
      */
     static boolean detectLoop(Node head) {
         Node sptr = head;
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java b/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java
index 5e9d4c3a2913..2e1012f2b79b 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java
@@ -12,7 +12,7 @@ public class CreateAndDetectLoopTest {
 
     @BeforeEach
     void setUp() {
-        // Create a linked list: 1 -> 2 -> 3 -> 4 -> 5 -> 6
+        // Set up a linked list: 1 -> 2 -> 3 -> 4 -> 5 -> 6
         head = new CreateAndDetectLoop.Node(1);
         CreateAndDetectLoop.Node second = new CreateAndDetectLoop.Node(2);
         CreateAndDetectLoop.Node third = new CreateAndDetectLoop.Node(3);
@@ -44,7 +44,7 @@ void testCreateAndDetectLoopLoopExists() {
 
     @Test
     void testCreateLoopInvalidPosition() {
-        // Create loop with invalid positions
+        // Create loop with invalid positions (0)
         CreateAndDetectLoop.createLoop(head, 0, 0);
 
         // Ensure no loop was created
@@ -62,10 +62,25 @@ void testCreateLoopSelfLoop() {
 
     @Test
     void testCreateLoopNoChangeForNonExistentPositions() {
-        // Create a loop with positions that don't exist in the linked list
+        // Create a loop with non-existent positions
         CreateAndDetectLoop.createLoop(head, 10, 20);
 
         // Ensure no loop was created
         assertFalse(CreateAndDetectLoop.detectLoop(head), "No loop should be created if positions are out of bounds.");
     }
+
+    @Test
+    void testMultipleNodesWithNoLoop() {
+        // Multiple nodes without creating any loop
+        assertFalse(CreateAndDetectLoop.detectLoop(head), "No loop should be detected for a standard linear list.");
+    }
+
+    @Test
+    void testHeadToTailLoop() {
+        // Create a loop from the tail back to the head
+        CreateAndDetectLoop.createLoop(head, 1, 6);
+
+        // Detect the head-to-tail loop
+        assertTrue(CreateAndDetectLoop.detectLoop(head), "A head-to-tail loop should be detected.");
+    }
 }

From 3a8b04afeabd99de6e927edde4821d01937b2c3b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 25 Oct 2024 20:19:55 +0530
Subject: [PATCH 0611/1338] Enhance docs, add tests in MergeKSortedLinkedList
 (#5995)

---
 DIRECTORY.md                                  |  1 +
 .../lists/MergeKSortedLinkedList.java         | 85 ++++++++++++-----
 .../lists/MergeKSortedLinkedListTest.java     | 93 +++++++++++++++++++
 3 files changed, 158 insertions(+), 21 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 95805ff411eb..820b80cde7ed 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -830,6 +830,7 @@
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
               * [CreateAndDetectLoopTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java)
+              * [MergeKSortedLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java)
               * [MergeSortedArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java)
               * [MergeSortedSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java)
               * [QuickSortLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java
index 0eac20d2e9ad..0f5c50530d92 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java
@@ -1,51 +1,94 @@
 package com.thealgorithms.datastructures.lists;
 
-import java.util.Arrays;
 import java.util.Comparator;
 import java.util.PriorityQueue;
 
 /**
+ * The MergeKSortedLinkedList class provides a method to merge multiple sorted linked lists
+ * into a single sorted linked list.
+ * This implementation uses a min-heap (priority queue) to efficiently
+ * find the smallest node across all lists, thus optimizing the merge process.
+ *
+ * <p>Example usage:
+ * <pre>
+ * Node list1 = new Node(1, new Node(4, new Node(5)));
+ * Node list2 = new Node(1, new Node(3, new Node(4)));
+ * Node list3 = new Node(2, new Node(6));
+ * Node[] lists = { list1, list2, list3 };
+ *
+ * MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+ * Node mergedHead = merger.mergeKList(lists, lists.length);
+ * </pre>
+ * </p>
+ *
+ * <p>This class is designed to handle nodes of integer linked lists and can be expanded for additional data types if needed.</p>
+ *
  * @author Arun Pandey (https://github.com/pandeyarun709)
  */
 public class MergeKSortedLinkedList {
 
     /**
-     * This function merge K sorted LinkedList
+     * Merges K sorted linked lists into a single sorted linked list.
      *
-     * @param a array of LinkedList
-     * @param n size of array
-     * @return node
+     * <p>This method uses a priority queue (min-heap) to repeatedly extract the smallest node from the heads of all the lists,
+     * then inserts the next node from that list into the heap. The process continues until all nodes have been processed,
+     * resulting in a fully merged and sorted linked list.</p>
+     *
+     * @param a Array of linked list heads to be merged.
+     * @param n Number of linked lists.
+     * @return Head of the merged sorted linked list.
      */
     Node mergeKList(Node[] a, int n) {
-        // Min Heap
-        PriorityQueue<Node> min = new PriorityQueue<>(Comparator.comparingInt(x -> x.data));
+        if (a == null || n == 0) {
+            return null;
+        }
 
-        // adding head of all linkedList in min heap
-        min.addAll(Arrays.asList(a).subList(0, n));
+        // Min Heap to store nodes based on their values for efficient retrieval of the smallest element.
+        PriorityQueue<Node> minHeap = new PriorityQueue<>(Comparator.comparingInt(x -> x.data));
 
-        // Make new head among smallest heads in K linkedList
-        Node head = min.poll();
-        min.add(head.next);
-        Node curr = head;
+        // Initialize the min-heap with the head of each non-null linked list
+        for (Node node : a) {
+            if (node != null) {
+                minHeap.add(node);
+            }
+        }
+
+        // Start merging process
+        Node head = minHeap.poll(); // Smallest head is the initial head of the merged list
+        if (head != null && head.next != null) {
+            minHeap.add(head.next);
+        }
 
-        // merging LinkedList
-        while (!min.isEmpty()) {
-            Node temp = min.poll();
+        Node curr = head;
+        while (!minHeap.isEmpty()) {
+            Node temp = minHeap.poll();
             curr.next = temp;
             curr = temp;
 
-            // Add Node in min Heap only if temp.next is not null
+            // Add the next node in the current list to the heap if it exists
             if (temp.next != null) {
-                min.add(temp.next);
+                minHeap.add(temp.next);
             }
         }
 
         return head;
     }
 
-    private final class Node {
+    /**
+     * Represents a node in the linked list.
+     */
+    static class Node {
+        int data;
+        Node next;
+
+        Node(int data) {
+            this.data = data;
+            this.next = null;
+        }
 
-        private int data;
-        private Node next;
+        Node(int data, Node next) {
+            this.data = data;
+            this.next = next;
+        }
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java
new file mode 100644
index 000000000000..99a890112d31
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java
@@ -0,0 +1,93 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import com.thealgorithms.datastructures.lists.MergeKSortedLinkedList.Node;
+import java.util.Arrays;
+import org.junit.jupiter.api.Test;
+
+class MergeKSortedLinkedListTest {
+
+    @Test
+    void testMergeKLists() {
+        Node list1 = new Node(1, new Node(4, new Node(5)));
+        Node list2 = new Node(1, new Node(3, new Node(4)));
+        Node list3 = new Node(2, new Node(6));
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 1, 2, 3, 4, 4, 5, 6};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Merged list values do not match the expected sorted order.");
+    }
+
+    @Test
+    void testMergeEmptyLists() {
+        Node[] lists = {null, null, null};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        assertNull(mergedHead, "Merged list should be null when all input lists are empty.");
+    }
+
+    @Test
+    void testMergeSingleList() {
+        Node list1 = new Node(1, new Node(3, new Node(5)));
+        Node[] lists = {list1};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 3, 5};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Merged list should match the single input list when only one list is provided.");
+    }
+
+    @Test
+    void testMergeListsOfDifferentLengths() {
+        Node list1 = new Node(1, new Node(3, new Node(5)));
+        Node list2 = new Node(2, new Node(4));
+        Node list3 = new Node(6);
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 2, 3, 4, 5, 6};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Merged list values do not match expected sorted order for lists of different lengths.");
+    }
+
+    @Test
+    void testMergeSingleElementLists() {
+        Node list1 = new Node(1);
+        Node list2 = new Node(3);
+        Node list3 = new Node(2);
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 2, 3};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Merged list values do not match expected sorted order for single-element lists.");
+    }
+
+    /**
+     * Helper method to extract values from the linked list into an array for assertion.
+     */
+    private int[] getListValues(Node head) {
+        int[] values = new int[100]; // assuming max length for simplicity
+        int i = 0;
+        Node curr = head;
+        while (curr != null) {
+            values[i++] = curr.data;
+            curr = curr.next;
+        }
+        return Arrays.copyOf(values, i); // return only filled part
+    }
+}

From f3e0900d2b86aecf69b2c519e1defac6f8e5181c Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 25 Oct 2024 20:31:06 +0530
Subject: [PATCH 0612/1338] Enhance docs, add tests in `CursorLinkedList`
 (#5994)

---
 DIRECTORY.md                                  |   1 +
 .../lists/CursorLinkedList.java               | 142 ++++++++++--------
 .../lists/CursorLinkedListTest.java           | 112 ++++++++++++++
 3 files changed, 196 insertions(+), 59 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 820b80cde7ed..6a733019a679 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -830,6 +830,7 @@
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
               * [CreateAndDetectLoopTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java)
+              * [CursorLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java)
               * [MergeKSortedLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java)
               * [MergeSortedArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java)
               * [MergeSortedSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
index b4fa9c51d4dc..ff3d39115c3b 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
@@ -3,18 +3,20 @@
 import java.util.Objects;
 
 /**
- * This class implements a Cursor Linked List.
- *
- * A CursorLinkedList is an array version of a Linked List. Essentially you have
- * an array of list nodes but instead of each node containing a pointer to the
- * next item in the linked list, each node element in the array contains the
- * index for the next node element.
+ * CursorLinkedList is an array-based implementation of a singly linked list.
+ * Each node in the array simulates a linked list node, storing an element and
+ * the index of the next node. This structure allows for efficient list operations
+ * without relying on traditional pointers.
  *
+ * @param <T> the type of elements in this list
  */
 public class CursorLinkedList<T> {
 
+    /**
+     * Node represents an individual element in the list, containing the element
+     * itself and a pointer (index) to the next node.
+     */
     private static class Node<T> {
-
         T element;
         int next;
 
@@ -31,7 +33,7 @@ private static class Node<T> {
     private static final int CURSOR_SPACE_SIZE = 100;
 
     {
-        // init at loading time
+        // Initialize cursor space array and free list pointers
         cursorSpace = new Node[CURSOR_SPACE_SIZE];
         for (int i = 0; i < CURSOR_SPACE_SIZE; i++) {
             cursorSpace[i] = new Node<>(null, i + 1);
@@ -39,12 +41,18 @@ private static class Node<T> {
         cursorSpace[CURSOR_SPACE_SIZE - 1].next = 0;
     }
 
+    /**
+     * Constructs an empty CursorLinkedList with the default capacity.
+     */
     public CursorLinkedList() {
         os = 0;
         count = 0;
         head = -1;
     }
 
+    /**
+     * Prints all elements in the list in their current order.
+     */
     public void printList() {
         if (head != -1) {
             int start = head;
@@ -57,27 +65,36 @@ public void printList() {
     }
 
     /**
-     * @return the logical index of the element within the list , not the actual
-     * index of the [cursorSpace] array
+     * Finds the logical index of a specified element in the list.
+     *
+     * @param element the element to search for in the list
+     * @return the logical index of the element, or -1 if not found
+     * @throws NullPointerException if element is null
      */
     public int indexOf(T element) {
-        Objects.requireNonNull(element);
-        Node<T> iterator = cursorSpace[head];
-        for (int i = 0; i < count; i++) {
-            if (iterator.element.equals(element)) {
-                return i;
+        if (element == null) {
+            throw new NullPointerException("Element cannot be null");
+        }
+        try {
+            Objects.requireNonNull(element);
+            Node<T> iterator = cursorSpace[head];
+            for (int i = 0; i < count; i++) {
+                if (iterator.element.equals(element)) {
+                    return i;
+                }
+                iterator = cursorSpace[iterator.next];
             }
-            iterator = cursorSpace[iterator.next];
+        } catch (Exception e) {
+            return -1;
         }
-
         return -1;
     }
 
     /**
-     * @param position , the logical index of the element , not the actual one
-     * within the [cursorSpace] array . this method should be used to get the
-     * index give by indexOf() method.
-     * @return
+     * Retrieves an element at a specified logical index in the list.
+     *
+     * @param position the logical index of the element
+     * @return the element at the specified position, or null if index is out of bounds
      */
     public T get(int position) {
         if (position >= 0 && position < count) {
@@ -88,15 +105,18 @@ public T get(int position) {
                 if (counter == position) {
                     return element;
                 }
-
                 start = cursorSpace[start].next;
                 counter++;
             }
         }
-
         return null;
     }
 
+    /**
+     * Removes the element at a specified logical index from the list.
+     *
+     * @param index the logical index of the element to remove
+     */
     public void removeByIndex(int index) {
         if (index >= 0 && index < count) {
             T element = get(index);
@@ -104,19 +124,22 @@ public void removeByIndex(int index) {
         }
     }
 
+    /**
+     * Removes a specified element from the list.
+     *
+     * @param element the element to be removed
+     * @throws NullPointerException if element is null
+     */
     public void remove(T element) {
         Objects.requireNonNull(element);
-
-        // case element is in the head
         T tempElement = cursorSpace[head].element;
         int tempNext = cursorSpace[head].next;
         if (tempElement.equals(element)) {
             free(head);
             head = tempNext;
-        } else { // otherwise cases
+        } else {
             int prevIndex = head;
             int currentIndex = cursorSpace[prevIndex].next;
-
             while (currentIndex != -1) {
                 T currentElement = cursorSpace[currentIndex].element;
                 if (currentElement.equals(element)) {
@@ -124,15 +147,34 @@ public void remove(T element) {
                     free(currentIndex);
                     break;
                 }
-
                 prevIndex = currentIndex;
                 currentIndex = cursorSpace[prevIndex].next;
             }
         }
-
         count--;
     }
 
+    /**
+     * Allocates a new node index for storing an element.
+     *
+     * @return the index of the newly allocated node
+     * @throws OutOfMemoryError if no space is available in cursor space
+     */
+    private int alloc() {
+        int availableNodeIndex = cursorSpace[os].next;
+        if (availableNodeIndex == 0) {
+            throw new OutOfMemoryError();
+        }
+        cursorSpace[os].next = cursorSpace[availableNodeIndex].next;
+        cursorSpace[availableNodeIndex].next = -1;
+        return availableNodeIndex;
+    }
+
+    /**
+     * Releases a node back to the free list.
+     *
+     * @param index the index of the node to release
+     */
     private void free(int index) {
         Node<T> osNode = cursorSpace[os];
         int osNext = osNode.next;
@@ -141,44 +183,26 @@ private void free(int index) {
         cursorSpace[index].next = osNext;
     }
 
+    /**
+     * Appends an element to the end of the list.
+     *
+     * @param element the element to append
+     * @throws NullPointerException if element is null
+     */
     public void append(T element) {
         Objects.requireNonNull(element);
         int availableIndex = alloc();
         cursorSpace[availableIndex].element = element;
-
         if (head == -1) {
             head = availableIndex;
+        } else {
+            int iterator = head;
+            while (cursorSpace[iterator].next != -1) {
+                iterator = cursorSpace[iterator].next;
+            }
+            cursorSpace[iterator].next = availableIndex;
         }
-
-        int iterator = head;
-        while (cursorSpace[iterator].next != -1) {
-            iterator = cursorSpace[iterator].next;
-        }
-
-        cursorSpace[iterator].next = availableIndex;
         cursorSpace[availableIndex].next = -1;
-
         count++;
     }
-
-    /**
-     * @return the index of the next available node
-     */
-    private int alloc() {
-        // 1- get the index at which the os is pointing
-        int availableNodeIndex = cursorSpace[os].next;
-
-        if (availableNodeIndex == 0) {
-            throw new OutOfMemoryError();
-        }
-
-        // 2- make the os point to the next of the  @var{availableNodeIndex}
-        cursorSpace[os].next = cursorSpace[availableNodeIndex].next;
-
-        // this to indicate an end of the list , helpful at testing since any err
-        // would throw an outOfBoundException
-        cursorSpace[availableNodeIndex].next = -1;
-
-        return availableNodeIndex;
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java
new file mode 100644
index 000000000000..bf5501826994
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java
@@ -0,0 +1,112 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class CursorLinkedListTest {
+    private CursorLinkedList<String> list;
+
+    @BeforeEach
+    void setUp() {
+        list = new CursorLinkedList<>();
+    }
+
+    @Test
+    void testAppendAndGet() {
+        list.append("First");
+        list.append("Second");
+        list.append("Third");
+
+        assertEquals("First", list.get(0));
+        assertEquals("Second", list.get(1));
+        assertEquals("Third", list.get(2));
+        assertNull(list.get(3));
+        assertNull(list.get(-1));
+    }
+
+    @Test
+    void testIndexOf() {
+        list.append("First");
+        list.append("Second");
+        list.append("Third");
+
+        assertEquals(0, list.indexOf("First"));
+        assertEquals(1, list.indexOf("Second"));
+        assertEquals(2, list.indexOf("Third"));
+        assertEquals(-1, list.indexOf("NonExistent"));
+    }
+
+    @Test
+    void testRemove() {
+        list.append("First");
+        list.append("Second");
+        list.append("Third");
+
+        list.remove("Second");
+        assertEquals("First", list.get(0));
+        assertEquals("Third", list.get(1));
+        assertNull(list.get(2));
+        assertEquals(-1, list.indexOf("Second"));
+    }
+
+    @Test
+    void testRemoveByIndex() {
+        list.append("First");
+        list.append("Second");
+        list.append("Third");
+
+        list.removeByIndex(1);
+        assertEquals("First", list.get(0));
+        assertEquals("Third", list.get(1));
+        assertNull(list.get(2));
+    }
+
+    @Test
+    void testRemoveFirstElement() {
+        list.append("First");
+        list.append("Second");
+
+        list.remove("First");
+        assertEquals("Second", list.get(0));
+        assertNull(list.get(1));
+        assertEquals(-1, list.indexOf("First"));
+    }
+
+    @Test
+    void testRemoveLastElement() {
+        list.append("First");
+        list.append("Second");
+
+        list.remove("Second");
+        assertEquals("First", list.get(0));
+        assertNull(list.get(1));
+        assertEquals(-1, list.indexOf("Second"));
+    }
+
+    @Test
+    void testNullHandling() {
+        assertThrows(NullPointerException.class, () -> list.append(null));
+        assertThrows(NullPointerException.class, () -> list.remove(null));
+        assertThrows(NullPointerException.class, () -> list.indexOf(null));
+    }
+
+    @Test
+    void testEmptyList() {
+        assertNull(list.get(0));
+        assertEquals(-1, list.indexOf("Any"));
+    }
+
+    @Test
+    void testMemoryLimitExceeded() {
+        // Test adding more elements than CURSOR_SPACE_SIZE
+        assertThrows(OutOfMemoryError.class, () -> {
+            for (int i = 0; i < 101; i++) { // CURSOR_SPACE_SIZE is 100
+                list.append("Element" + i);
+            }
+        });
+    }
+}

From ed35374ab04fef115d198ef407322115633f27d0 Mon Sep 17 00:00:00 2001
From: jasonjyu <jason.j.yu@gmail.com>
Date: Fri, 25 Oct 2024 11:05:43 -0400
Subject: [PATCH 0613/1338] Add to WordLadderTest corner case where wordList is
 empty (#5908)

---
 .../com/thealgorithms/strings/WordLadderTest.java | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/test/java/com/thealgorithms/strings/WordLadderTest.java b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
index d933ebeddc53..0854ad2b0c1f 100644
--- a/src/test/java/com/thealgorithms/strings/WordLadderTest.java
+++ b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
@@ -41,6 +41,21 @@ public void testWordLadder2() {
         assertEquals(WordLadder.ladderLength("hit", "cog", wordList2), 0);
     }
 
+    /**
+     * Test 3:
+     * Input: beginWord = "hit", endWord = "cog", wordList =
+     * []
+     * Output: 0
+     * Explanation: The wordList is empty (corner case),
+     * therefore there is no valid transformation sequence.
+     */
+    @Test
+    public void testWordLadder3() {
+
+        List<String> wordList3 = Arrays.asList();
+        assertEquals(WordLadder.ladderLength("hit", "cog", wordList3), 0);
+    }
+
     @ParameterizedTest
     @CsvSource({"'a', 'c', 'b,c', 2", "'a', 'c', 'a', 0", "'a', 'a', 'a', 0", "'ab', 'cd', 'ad,bd,cd', 3", "'a', 'd', 'b,c,d', 2", "'a', 'd', 'b,c,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,d', 2"})
     void testLadderLength(String beginWord, String endWord, String wordListStr, int expectedLength) {

From c766c5e812a4940e6357a49c9a23aa95c8cd5a4b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 25 Oct 2024 20:40:15 +0530
Subject: [PATCH 0614/1338] =?UTF-8?q?Enhance=20docs,=20remove=20`main`,=20?=
 =?UTF-8?q?add=20tests=20in=20`CountSinglyLinke=E2=80=A6=20(#5992)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 DIRECTORY.md                                  |  1 +
 .../lists/CountSinglyLinkedListRecursion.java | 23 +++++----
 .../CountSinglyLinkedListRecursionTest.java   | 49 +++++++++++++++++++
 3 files changed, 61 insertions(+), 12 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6a733019a679..744e16db8d6b 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -829,6 +829,7 @@
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
+              * [CountSinglyLinkedListRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java)
               * [CreateAndDetectLoopTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java)
               * [CursorLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java)
               * [MergeKSortedLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java b/src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java
index 8d864bc8caae..4c1ffe9d3ea4 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java
@@ -1,27 +1,26 @@
 package com.thealgorithms.datastructures.lists;
 
+/**
+ * CountSinglyLinkedListRecursion extends a singly linked list to include a
+ * recursive count method, which calculates the number of nodes in the list.
+ */
 public class CountSinglyLinkedListRecursion extends SinglyLinkedList {
 
-    public static void main(String[] args) {
-        CountSinglyLinkedListRecursion list = new CountSinglyLinkedListRecursion();
-        for (int i = 1; i <= 5; ++i) {
-            list.insert(i);
-        }
-        assert list.count() == 5;
-    }
-
     /**
-     * Calculate the count of the list manually using recursion.
+     * Recursively calculates the number of nodes in the list.
      *
-     * @param head head of the list.
-     * @return count of the list.
+     * @param head the head node of the list segment being counted.
+     * @return the count of nodes from the given head node onward.
      */
     private int countRecursion(Node head) {
         return head == null ? 0 : 1 + countRecursion(head.next);
     }
 
     /**
-     * Returns the count of the list.
+     * Returns the total number of nodes in the list by invoking the recursive
+     * count helper method.
+     *
+     * @return the total node count in the list.
      */
     @Override
     public int count() {
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java b/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java
new file mode 100644
index 000000000000..1a3efe8a5572
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java
@@ -0,0 +1,49 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class CountSinglyLinkedListRecursionTest {
+
+    private CountSinglyLinkedListRecursion list;
+
+    @BeforeEach
+    public void setUp() {
+        list = new CountSinglyLinkedListRecursion();
+    }
+
+    @Test
+    public void testCountEmptyList() {
+        // An empty list should have a count of 0
+        assertEquals(0, list.count(), "Count of an empty list should be 0.");
+    }
+
+    @Test
+    public void testCountSingleElementList() {
+        // Insert a single element and check the count
+        list.insert(1);
+        assertEquals(1, list.count(), "Count of a single-element list should be 1.");
+    }
+
+    @Test
+    public void testCountMultipleElements() {
+        // Insert multiple elements and check the count
+        for (int i = 1; i <= 5; i++) {
+            list.insert(i);
+        }
+        assertEquals(5, list.count(), "Count of a list with 5 elements should be 5.");
+    }
+
+    @Test
+    public void testCountWithDuplicateElements() {
+        // Insert duplicate elements and verify the count is correct
+        list.insert(1);
+        list.insert(2);
+        list.insert(2);
+        list.insert(3);
+        list.insert(3);
+        assertEquals(5, list.count(), "Count of a list with duplicate elements should match total node count.");
+    }
+}

From 202879aa58dddf56c8dee9e53eeb178caaf620fb Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 25 Oct 2024 20:46:34 +0530
Subject: [PATCH 0615/1338] Enhance docs, add tests in `CircleLinkedList`
 (#5991)

---
 .../lists/CircleLinkedList.java               | 79 ++++++++++++------
 .../lists/CircleLinkedListTest.java           | 81 ++++++++++++++-----
 2 files changed, 114 insertions(+), 46 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
index 2b50f73101fb..422e8953625f 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
@@ -1,8 +1,23 @@
 package com.thealgorithms.datastructures.lists;
 
+/**
+ * This class is a circular singly linked list implementation. In a circular linked list,
+ * the last node points back to the first node, creating a circular chain.
+ *
+ * <p>This implementation includes basic operations such as appending elements
+ * to the end, removing elements from a specified position, and converting
+ * the list to a string representation.
+ *
+ * @param <E> the type of elements held in this list
+ */
 public class CircleLinkedList<E> {
 
-    private static final class Node<E> {
+    /**
+     * A static nested class representing a node in the circular linked list.
+     *
+     * @param <E> the type of element stored in the node
+     */
+    static final class Node<E> {
 
         Node<E> next;
         E value;
@@ -13,44 +28,56 @@ private Node(E value, Node<E> next) {
         }
     }
 
-    // For better O.O design this should be private allows for better black box design
     private int size;
-    // this will point to dummy node;
-    private Node<E> head = null;
-    private Node<E> tail = null; // keeping a tail pointer to keep track of the end of list
+    Node<E> head = null;
+    private Node<E> tail;
 
-    // constructor for class.. here we will make a dummy node for circly linked list implementation
-    // with reduced error catching as our list will never be empty;
+    /**
+     * Initializes a new circular linked list. A dummy head node is used for simplicity,
+     * pointing initially to itself to ensure the list is never empty.
+     */
     public CircleLinkedList() {
-        // creation of the dummy node
-        head = new Node<E>(null, head);
+        head = new Node<>(null, head);
         tail = head;
         size = 0;
     }
 
-    // getter for the size... needed because size is private.
+    /**
+     * Returns the current size of the list.
+     *
+     * @return the number of elements in the list
+     */
     public int getSize() {
         return size;
     }
 
-    // for the sake of simplistiy this class will only contain the append function or addLast other
-    // add functions can be implemented however this is the basses of them all really.
+    /**
+     * Appends a new element to the end of the list. Throws a NullPointerException if
+     * a null value is provided.
+     *
+     * @param value the value to append to the list
+     * @throws NullPointerException if the value is null
+     */
     public void append(E value) {
         if (value == null) {
-            // we do not want to add null elements to the list.
             throw new NullPointerException("Cannot add null element to the list");
         }
-        // head.next points to the last element;
         if (tail == null) {
-            tail = new Node<E>(value, head);
+            tail = new Node<>(value, head);
             head.next = tail;
         } else {
-            tail.next = new Node<E>(value, head);
+            tail.next = new Node<>(value, head);
             tail = tail.next;
         }
         size++;
     }
 
+    /**
+     * Returns a string representation of the list in the format "[ element1, element2, ... ]".
+     * An empty list is represented as "[]".
+     *
+     * @return the string representation of the list
+     */
     public String toString() {
         if (size == 0) {
             return "[]";
@@ -68,23 +95,27 @@ public String toString() {
         return sb.toString();
     }
 
+    /**
+     * Removes and returns the element at the specified position in the list.
+     * Throws an IndexOutOfBoundsException if the position is invalid.
+     *
+     * @param pos the position of the element to remove
+     * @return the value of the removed element
+     * @throws IndexOutOfBoundsException if the position is out of range
+     */
     public E remove(int pos) {
         if (pos >= size || pos < 0) {
-            // catching errors
-            throw new IndexOutOfBoundsException("position cannot be greater than size or negative");
+            throw new IndexOutOfBoundsException("Position out of bounds");
         }
-        // we need to keep track of the element before the element we want to remove we can see why
-        // bellow.
+
         Node<E> before = head;
         for (int i = 1; i <= pos; i++) {
             before = before.next;
         }
         Node<E> destroy = before.next;
         E saved = destroy.value;
-        // assigning the next reference to the element following the element we want to remove...
-        // the last element will be assigned to the head.
-        before.next = before.next.next;
-        // scrubbing
+        before.next = destroy.next;
+
         if (destroy == tail) {
             tail = before;
         }
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java
index b7a05ef29d66..883d2b02ba7c 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java
@@ -1,78 +1,115 @@
 package com.thealgorithms.datastructures.lists;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 public class CircleLinkedListTest {
 
+    private CircleLinkedList<Integer> list;
+
+    @BeforeEach
+    public void setUp() {
+        list = new CircleLinkedList<>();
+    }
+
+    @Test
+    public void testInitialSize() {
+        assertEquals(0, list.getSize(), "Initial size should be 0.");
+    }
+
     @Test
     public void testAppendAndSize() {
-        CircleLinkedList<Integer> list = new CircleLinkedList<>();
         list.append(1);
         list.append(2);
         list.append(3);
 
-        assertEquals(3, list.getSize());
-        assertEquals("[ 1, 2, 3 ]", list.toString());
+        assertEquals(3, list.getSize(), "Size after three appends should be 3.");
+        assertEquals("[ 1, 2, 3 ]", list.toString(), "List content should match appended values.");
     }
 
     @Test
     public void testRemove() {
-        CircleLinkedList<Integer> list = new CircleLinkedList<>();
         list.append(1);
         list.append(2);
         list.append(3);
         list.append(4);
 
-        assertEquals(2, list.remove(1));
-        assertEquals(3, list.remove(1));
-        assertEquals("[ 1, 4 ]", list.toString());
-        assertEquals(2, list.getSize());
+        assertEquals(2, list.remove(1), "Removed element at index 1 should be 2.");
+        assertEquals(3, list.remove(1), "Removed element at index 1 after update should be 3.");
+        assertEquals("[ 1, 4 ]", list.toString(), "List content should reflect removals.");
+        assertEquals(2, list.getSize(), "Size after two removals should be 2.");
     }
 
     @Test
     public void testRemoveInvalidIndex() {
-        CircleLinkedList<Integer> list = new CircleLinkedList<>();
         list.append(1);
         list.append(2);
 
-        assertThrows(IndexOutOfBoundsException.class, () -> list.remove(2));
-        assertThrows(IndexOutOfBoundsException.class, () -> list.remove(-1));
+        assertThrows(IndexOutOfBoundsException.class, () -> list.remove(2), "Should throw on out-of-bounds index.");
+        assertThrows(IndexOutOfBoundsException.class, () -> list.remove(-1), "Should throw on negative index.");
     }
 
     @Test
     public void testToStringEmpty() {
-        CircleLinkedList<Integer> list = new CircleLinkedList<>();
-        assertEquals("[]", list.toString());
+        assertEquals("[]", list.toString(), "Empty list should be represented by '[]'.");
     }
 
     @Test
     public void testToStringAfterRemoval() {
-        CircleLinkedList<Integer> list = new CircleLinkedList<>();
         list.append(1);
         list.append(2);
         list.append(3);
         list.remove(1);
 
-        assertEquals("[ 1, 3 ]", list.toString());
+        assertEquals("[ 1, 3 ]", list.toString(), "List content should match remaining elements after removal.");
     }
 
     @Test
     public void testSingleElement() {
-        CircleLinkedList<Integer> list = new CircleLinkedList<>();
         list.append(1);
 
-        assertEquals(1, list.getSize());
-        assertEquals("[ 1 ]", list.toString());
-        assertEquals(1, list.remove(0));
-        assertEquals("[]", list.toString());
+        assertEquals(1, list.getSize(), "Size after single append should be 1.");
+        assertEquals("[ 1 ]", list.toString(), "Single element list should display properly.");
+        assertEquals(1, list.remove(0), "Single element removed should match appended value.");
+        assertEquals("[]", list.toString(), "List should be empty after removing the single element.");
     }
 
     @Test
     public void testNullElement() {
-        CircleLinkedList<String> list = new CircleLinkedList<>();
-        assertThrows(NullPointerException.class, () -> list.append(null));
+        assertThrows(NullPointerException.class, () -> list.append(null), "Appending null should throw exception.");
+    }
+
+    @Test
+    public void testCircularReference() {
+        list.append(1);
+        list.append(2);
+        list.append(3);
+        CircleLinkedList.Node<Integer> current = list.head;
+
+        // Traverse one full cycle and verify the circular reference
+        for (int i = 0; i <= list.getSize(); i++) {
+            current = current.next;
+        }
+        assertEquals(list.head, current, "End of list should point back to the head (circular structure).");
+    }
+
+    @Test
+    public void testClear() {
+        list.append(1);
+        list.append(2);
+        list.append(3);
+
+        // Remove all elements to simulate clearing the list
+        for (int i = list.getSize() - 1; i >= 0; i--) {
+            list.remove(i);
+        }
+
+        assertEquals(0, list.getSize(), "Size after clearing should be 0.");
+        assertEquals("[]", list.toString(), "Empty list should be represented by '[]' after clear.");
+        assertSame(list.head.next, list.head, "Head's next should point to itself after clearing.");
     }
 }

From bc9645c0eadcba2283afbac8f8a769a0d5c05c78 Mon Sep 17 00:00:00 2001
From: PANKAJ PATWAL <120747214+Chiefpatwal@users.noreply.github.com>
Date: Fri, 25 Oct 2024 23:08:26 +0530
Subject: [PATCH 0616/1338] Add Sliding Window algorithm and tests for maximum
 sum of subarray (#6001)

---
 .../slidingwindow/MaxSumKSizeSubarray.java    | 50 ++++++++++++
 .../MaxSumKSizeSubarrayTest.java              | 79 +++++++++++++++++++
 2 files changed, 129 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java
 create mode 100644 src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java

diff --git a/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java b/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java
new file mode 100644
index 000000000000..7e8095e08a0b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java
@@ -0,0 +1,50 @@
+package com.thealgorithms.slidingwindow;
+
+/**
+ * The Sliding Window algorithm is used to find the maximum sum of a subarray
+ * of a fixed size k within a given array.
+ *
+ * <p>
+ * Worst-case performance O(n)
+ * Best-case performance O(n)
+ * Average performance O(n)
+ * Worst-case space complexity O(1)
+ *
+ * @author Your Name (https://github.com/Chiefpatwal)
+ */
+public final class MaxSumKSizeSubarray {
+
+    // Prevent instantiation
+    private MaxSumKSizeSubarray() {
+    }
+
+    /**
+     * This method finds the maximum sum of a subarray of a given size k.
+     *
+     * @param arr is the input array where the maximum sum needs to be found
+     * @param k   is the size of the subarray
+     * @return the maximum sum of the subarray of size k
+     */
+    public static int maxSumKSizeSubarray(int[] arr, int k) {
+        if (arr.length < k) {
+            return -1; // Edge case: not enough elements
+        }
+
+        int maxSum;
+        int windowSum = 0;
+
+        // Calculate the sum of the first window
+        for (int i = 0; i < k; i++) {
+            windowSum += arr[i];
+        }
+        maxSum = windowSum;
+
+        // Slide the window across the array
+        for (int i = k; i < arr.length; i++) {
+            windowSum += arr[i] - arr[i - k];
+            maxSum = Math.max(maxSum, windowSum);
+        }
+
+        return maxSum;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java b/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java
new file mode 100644
index 000000000000..aa3c2eae3294
--- /dev/null
+++ b/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java
@@ -0,0 +1,79 @@
+package com.thealgorithms.slidingwindow;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the MaxSumKSizeSubarray class.
+ *
+ * @author Your Name (https://github.com/Chiefpatwal)
+ */
+class MaxSumKSizeSubarrayTest {
+
+    /**
+     * Test for the basic case of finding the maximum sum.
+     */
+    @Test
+    void testMaxSumKSizeSubarray() {
+        int[] arr = {1, 2, 3, 4, 5};
+        int k = 2;
+        int expectedMaxSum = 9; // 4 + 5
+        assertEquals(expectedMaxSum, MaxSumKSizeSubarray.maxSumKSizeSubarray(arr, k));
+    }
+
+    /**
+     * Test for a different array and subarray size.
+     */
+    @Test
+    void testMaxSumKSizeSubarrayWithDifferentValues() {
+        int[] arr = {2, 1, 5, 1, 3, 2};
+        int k = 3;
+        int expectedMaxSum = 9; // 5 + 1 + 3
+        assertEquals(expectedMaxSum, MaxSumKSizeSubarray.maxSumKSizeSubarray(arr, k));
+    }
+
+    /**
+     * Test for edge case with insufficient elements.
+     */
+    @Test
+    void testMaxSumKSizeSubarrayWithInsufficientElements() {
+        int[] arr = {1, 2};
+        int k = 3; // Not enough elements
+        int expectedMaxSum = -1; // Edge case
+        assertEquals(expectedMaxSum, MaxSumKSizeSubarray.maxSumKSizeSubarray(arr, k));
+    }
+
+    /**
+     * Test for large array.
+     */
+    @Test
+    void testMaxSumKSizeSubarrayWithLargeArray() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        int k = 5;
+        int expectedMaxSum = 40; // 6 + 7 + 8 + 9 + 10
+        assertEquals(expectedMaxSum, MaxSumKSizeSubarray.maxSumKSizeSubarray(arr, k));
+    }
+
+    /**
+     * Test for array with negative numbers.
+     */
+    @Test
+    void testMaxSumKSizeSubarrayWithNegativeNumbers() {
+        int[] arr = {-1, -2, -3, -4, -5};
+        int k = 2;
+        int expectedMaxSum = -3; // -1 + -2
+        assertEquals(expectedMaxSum, MaxSumKSizeSubarray.maxSumKSizeSubarray(arr, k));
+    }
+
+    /**
+     * Test for the case where k equals the array length.
+     */
+    @Test
+    void testMaxSumKSizeSubarrayWithKEqualToArrayLength() {
+        int[] arr = {1, 2, 3, 4, 5};
+        int k = 5;
+        int expectedMaxSum = 15; // 1 + 2 + 3 + 4 + 5
+        assertEquals(expectedMaxSum, MaxSumKSizeSubarray.maxSumKSizeSubarray(arr, k));
+    }
+}

From e154a501057f8bab3697531d0246f6eb2629d6e6 Mon Sep 17 00:00:00 2001
From: KhalidDev <148249284+devAlq@users.noreply.github.com>
Date: Fri, 25 Oct 2024 20:48:00 +0300
Subject: [PATCH 0617/1338] Fix typo in README.md (#5895)

---
 src/main/java/com/thealgorithms/datastructures/lists/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/README.md b/src/main/java/com/thealgorithms/datastructures/lists/README.md
index ea389c0422ce..6aefa4c98e6d 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/README.md
+++ b/src/main/java/com/thealgorithms/datastructures/lists/README.md
@@ -1,7 +1,7 @@
 ## Linked List
 ### Description
 
-LinkedList is a data structure in which data is stored in a linear manner. It usually contains a data field and a link to the memory location of the next mode.
+LinkedList is a data structure in which data is stored in a linear manner. It usually contains a data field and a link to the memory location of the next node.
 
 ### Structure
 

From 3b2ba488bbcd8c2ed5d8e6c4d4596b67d44c4593 Mon Sep 17 00:00:00 2001
From: Ayush Kumar <119495476+SuprHUlk@users.noreply.github.com>
Date: Fri, 25 Oct 2024 23:21:31 +0530
Subject: [PATCH 0618/1338] Add chinese remainder theorem (#5873)

---
 .../maths/ChineseRemainderTheorem.java        | 84 +++++++++++++++++++
 .../maths/ChineseRemainderTheoremTest.java    | 54 ++++++++++++
 2 files changed, 138 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java
 create mode 100644 src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java

diff --git a/src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java b/src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java
new file mode 100644
index 000000000000..c26e67cffb59
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java
@@ -0,0 +1,84 @@
+package com.thealgorithms.maths;
+
+import java.util.List;
+
+/**
+ * @brief Implementation of the Chinese Remainder Theorem (CRT) algorithm
+ * @details
+ * The Chinese Remainder Theorem (CRT) is used to solve systems of
+ * simultaneous congruences. Given several pairwise coprime moduli
+ * and corresponding remainders, the algorithm finds the smallest
+ * positive solution.
+ */
+public final class ChineseRemainderTheorem {
+    private ChineseRemainderTheorem() {
+    }
+
+    /**
+     * @brief Solves the Chinese Remainder Theorem problem.
+     * @param remainders The list of remainders.
+     * @param moduli The list of pairwise coprime moduli.
+     * @return The smallest positive solution that satisfies all the given congruences.
+     */
+    public static int solveCRT(List<Integer> remainders, List<Integer> moduli) {
+        int product = 1;
+        int result = 0;
+
+        // Calculate the product of all moduli
+        for (int mod : moduli) {
+            product *= mod;
+        }
+
+        // Apply the formula for each congruence
+        for (int i = 0; i < moduli.size(); i++) {
+            int partialProduct = product / moduli.get(i);
+            int inverse = modInverse(partialProduct, moduli.get(i));
+            result += remainders.get(i) * partialProduct * inverse;
+        }
+
+        // Adjust result to be the smallest positive solution
+        result = result % product;
+        if (result < 0) {
+            result += product;
+        }
+
+        return result;
+    }
+
+    /**
+     * @brief Computes the modular inverse of a number with respect to a modulus using
+     * the Extended Euclidean Algorithm.
+     * @param a The number for which to find the inverse.
+     * @param m The modulus.
+     * @return The modular inverse of a modulo m.
+     */
+    private static int modInverse(int a, int m) {
+        int m0 = m;
+        int x0 = 0;
+        int x1 = 1;
+
+        if (m == 1) {
+            return 0;
+        }
+
+        while (a > 1) {
+            int q = a / m;
+            int t = m;
+
+            // m is remainder now, process same as Euclid's algorithm
+            m = a % m;
+            a = t;
+            t = x0;
+
+            x0 = x1 - q * x0;
+            x1 = t;
+        }
+
+        // Make x1 positive
+        if (x1 < 0) {
+            x1 += m0;
+        }
+
+        return x1;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java b/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java
new file mode 100644
index 000000000000..31c676d6e7b4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class ChineseRemainderTheoremTest {
+    @Test
+    public void testCRTSimpleCase() {
+        List<Integer> remainders = Arrays.asList(2, 3, 2);
+        List<Integer> moduli = Arrays.asList(3, 5, 7);
+        int expected = 23;
+        int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCRTLargeModuli() {
+        List<Integer> remainders = Arrays.asList(1, 2, 3);
+        List<Integer> moduli = Arrays.asList(5, 7, 9);
+        int expected = 156;
+        int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCRTWithSingleCongruence() {
+        List<Integer> remainders = Arrays.asList(4);
+        List<Integer> moduli = Arrays.asList(7);
+        int expected = 4;
+        int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCRTWithMultipleSolutions() {
+        List<Integer> remainders = Arrays.asList(0, 3);
+        List<Integer> moduli = Arrays.asList(4, 5);
+        int expected = 8;
+        int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCRTLargeNumbers() {
+        List<Integer> remainders = Arrays.asList(0, 4, 6);
+        List<Integer> moduli = Arrays.asList(11, 13, 17);
+        int expected = 550;
+        int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
+        assertEquals(expected, result);
+    }
+}

From 131e5381be23718cda8ce1a56adaeb0f972afdc8 Mon Sep 17 00:00:00 2001
From: Giulio Tantaro <giulio.tantaro@gmail.com>
Date: Fri, 25 Oct 2024 19:56:54 +0200
Subject: [PATCH 0619/1338] Add tests Generic Heap and add check null item
 (#5801)

---
 .../datastructures/heaps/GenericHeap.java     |   4 +
 .../datastructures/heaps/GenericHeapTest.java | 126 ++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java
index d546b7cc88d4..f1772b5b3112 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java
@@ -9,6 +9,10 @@ public class GenericHeap<T extends Comparable<T>> {
     HashMap<T, Integer> map = new HashMap<>();
 
     public void add(T item) {
+        if (item == null) {
+            throw new IllegalArgumentException("Cannot insert null into the heap.");
+        }
+
         this.data.add(item);
         map.put(item, this.data.size() - 1); //
         upHeapify(this.data.size() - 1);
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java
new file mode 100644
index 000000000000..8915a6d8aef2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java
@@ -0,0 +1,126 @@
+package com.thealgorithms.datastructures.heaps;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class GenericHeapTest {
+
+    private GenericHeap<Integer> heap;
+
+    @BeforeEach
+    public void setUp() {
+        heap = new GenericHeap<>();
+    }
+
+    @Test
+    public void testGenericHeapAddAndGet() {
+        heap.add(19);
+        heap.add(36);
+        heap.add(100);
+        heap.add(-17);
+        heap.add(3);
+
+        // Check that the largest element (100) is at the top of the heap
+        assertEquals(100, heap.get());
+    }
+
+    @Test
+    public void testGenericHeapRemove() {
+        heap.add(19);
+        heap.add(36);
+        heap.add(100);
+        heap.add(-17);
+        heap.add(3);
+
+        // Verify that the largest element is removed correctly
+        assertEquals(100, heap.remove());
+
+        // The new element at the top should be 36
+        assertEquals(36, heap.get());
+
+        // Check that the size is correct after removal
+        assertEquals(4, heap.size());
+    }
+
+    @Test
+    public void testGenericHeapSize() {
+        assertTrue(heap.isEmpty());
+
+        heap.add(10);
+        heap.add(20);
+
+        // Check that the size is correct
+        assertEquals(2, heap.size());
+
+        heap.remove();
+
+        // After removal, the size should be 1
+        assertEquals(1, heap.size());
+    }
+
+    @Test
+    public void testGenericHeapIsEmpty() {
+        // Verify that the heap is initially empty
+        assertTrue(heap.isEmpty());
+
+        heap.add(15);
+
+        // Now the heap should not be empty
+        assertFalse(heap.isEmpty());
+
+        heap.remove();
+
+        // After removing the one element, it should be empty again
+        assertTrue(heap.isEmpty());
+    }
+
+    @Test
+    public void testGenericHeapUpdatePriority() {
+        heap.add(19);
+        heap.add(36);
+        heap.add(100);
+        heap.add(-17);
+        heap.add(3);
+
+        // Verify that the largest element initially is 100
+        assertEquals(100, heap.get());
+
+        heap.remove();
+
+        // Simulates a change in priority by increasing the value of 100 to 44
+        heap.add(44);
+
+        // Now, the new high should be 25
+        assertEquals(44, heap.get());
+    }
+
+    @Test
+    public void testGenericHeapRemoveUntilEmpty() {
+        heap.add(5);
+        heap.add(3);
+        heap.add(4);
+        heap.add(1);
+        heap.add(2);
+
+        // Remove all items and check that they are removed in descending order
+        assertEquals(5, heap.remove());
+        assertEquals(4, heap.remove());
+        assertEquals(3, heap.remove());
+        assertEquals(2, heap.remove());
+        assertEquals(1, heap.remove());
+
+        // Empty heap
+        assertTrue(heap.isEmpty());
+    }
+
+    @Test
+    public void testGenericHeapAddNullItem() {
+        // Check null item
+        assertThrows(IllegalArgumentException.class, () -> { heap.add(null); });
+    }
+}

From cebefbc8b60cb6825960cecc24d90b0f3cb6f793 Mon Sep 17 00:00:00 2001
From: Giulio Tantaro <giulio.tantaro@gmail.com>
Date: Fri, 25 Oct 2024 21:18:32 +0200
Subject: [PATCH 0620/1338] Add tests Tower of Hanoi (#5736)


From 135fb08224046de3d607391c89e37287b6f9e41a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 00:53:20 +0530
Subject: [PATCH 0621/1338] Add `EgyptianFraction` algorithm (#5804)

---
 DIRECTORY.md                                  |  9 +++++
 .../greedyalgorithms/EgyptianFraction.java    | 35 +++++++++++++++++++
 .../EgyptianFractionTest.java                 | 22 ++++++++++++
 3 files changed, 66 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/EgyptianFraction.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/EgyptianFractionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 744e16db8d6b..98fbec625f5f 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -321,6 +321,7 @@
             * [BinaryAddition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java)
             * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java)
             * [DigitSeparation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java)
+            * [EgyptianFraction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/EgyptianFraction.java)
             * [FractionalKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
             * [GaleShapley](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java)
             * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
@@ -351,6 +352,7 @@
             * [BinaryPow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinaryPow.java)
             * [BinomialCoefficient](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java)
             * [Ceil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Ceil.java)
+            * [ChineseRemainderTheorem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java)
             * [CircularConvolutionFFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java)
             * [CollatzConjecture](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CollatzConjecture.java)
             * [Combinations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Combinations.java)
@@ -568,6 +570,8 @@
             * [TernarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/TernarySearch.java)
             * [UnionFind](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UnionFind.java)
             * [UpperBound](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UpperBound.java)
+          * slidingwindow
+            * [MaxSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java)
           * sorts
             * [AdaptiveMergeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java)
             * [BeadSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BeadSort.java)
@@ -826,6 +830,7 @@
               * [HashMapCuckooHashingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java)
             * heaps
               * [FibonacciHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
+              * [GenericHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java)
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
@@ -942,6 +947,7 @@
             * [BinaryAdditionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java)
             * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java)
             * [DigitSeparationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java)
+            * [EgyptianFractionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/EgyptianFractionTest.java)
             * [FractionalKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
             * [GaleShapleyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java)
             * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
@@ -969,6 +975,7 @@
             * [BinaryPowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinaryPowTest.java)
             * [BinomialCoefficientTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinomialCoefficientTest.java)
             * [CeilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CeilTest.java)
+            * [ChineseRemainderTheoremTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java)
             * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
             * [CombinationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CombinationsTest.java)
             * [ConvolutionFFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java)
@@ -1155,6 +1162,8 @@
             * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
             * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java)
             * [UpperBoundTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UpperBoundTest.java)
+          * slidingwindow
+            * [MaxSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java)
           * sorts
             * [AdaptiveMergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java)
             * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/EgyptianFraction.java b/src/main/java/com/thealgorithms/greedyalgorithms/EgyptianFraction.java
new file mode 100644
index 000000000000..35cbfe876b05
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/EgyptianFraction.java
@@ -0,0 +1,35 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Class to represent a fraction as a sum of unique unit fractions.
+ * Example:
+ * 2/3 = 1/2 + 1/6
+ * 3/10 = 1/4 + 1/20
+ *
+ * @author Hardvan
+ */
+public final class EgyptianFraction {
+    private EgyptianFraction() {
+    }
+
+    /**
+     * Calculates the Egyptian Fraction representation of a given fraction.
+     *
+     * @param numerator   the numerator of the fraction
+     * @param denominator the denominator of the fraction
+     * @return List of unit fractions represented as strings "1/x"
+     */
+    public static List<String> getEgyptianFraction(int numerator, int denominator) {
+        List<String> result = new ArrayList<>();
+        while (numerator != 0) {
+            int x = (int) Math.ceil((double) denominator / numerator);
+            result.add("1/" + x);
+            numerator = numerator * x - denominator;
+            denominator = denominator * x;
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/EgyptianFractionTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/EgyptianFractionTest.java
new file mode 100644
index 000000000000..1d34876de864
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/EgyptianFractionTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class EgyptianFractionTest {
+
+    @ParameterizedTest
+    @MethodSource("fractionProvider")
+    public void testGetEgyptianFraction(int numerator, int denominator, List<String> expected) {
+        assertEquals(expected, EgyptianFraction.getEgyptianFraction(numerator, denominator));
+    }
+
+    private static Stream<Arguments> fractionProvider() {
+        return Stream.of(Arguments.of(2, 3, List.of("1/2", "1/6")), Arguments.of(3, 10, List.of("1/4", "1/20")), Arguments.of(1, 3, List.of("1/3")), Arguments.of(1, 2, List.of("1/2")), Arguments.of(4, 13, List.of("1/4", "1/18", "1/468")));
+    }
+}

From 0f1dcbe47930d9a30f1beaee359c183669b4d1fb Mon Sep 17 00:00:00 2001
From: PANKAJ PATWAL <120747214+Chiefpatwal@users.noreply.github.com>
Date: Sat, 26 Oct 2024 01:48:40 +0530
Subject: [PATCH 0622/1338] Add longest substring (#6007)

---
 ...stSubstringWithoutRepeatingCharacters.java | 46 +++++++++++++++++++
 ...bstringWithoutRepeatingCharactersTest.java | 23 ++++++++++
 2 files changed, 69 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java
 create mode 100644 src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java

diff --git a/src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java b/src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java
new file mode 100644
index 000000000000..0641730d8b09
--- /dev/null
+++ b/src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java
@@ -0,0 +1,46 @@
+package com.thealgorithms.slidingwindow;
+import java.util.HashSet;
+
+/**
+ * The Longest Substring Without Repeating Characters algorithm finds the length of
+ * the longest substring without repeating characters in a given string.
+ *
+ * <p>
+ * Worst-case performance O(n)
+ * Best-case performance O(n)
+ * Average performance O(n)
+ * Worst-case space complexity O(min(n, m)), where n is the length of the string
+ * and m is the size of the character set.
+ *
+ * @author  (https://github.com/Chiefpatwal)
+ */
+public final class LongestSubstringWithoutRepeatingCharacters {
+
+    // Prevent instantiation
+    private LongestSubstringWithoutRepeatingCharacters() {
+    }
+
+    /**
+     * This method finds the length of the longest substring without repeating characters.
+     *
+     * @param s is the input string
+     * @return the length of the longest substring without repeating characters
+     */
+    public static int lengthOfLongestSubstring(String s) {
+        int maxLength = 0;
+        int left = 0;
+        HashSet<Character> charSet = new HashSet<>();
+
+        for (int right = 0; right < s.length(); right++) {
+            // If the character is already in the set, remove characters from the left
+            while (charSet.contains(s.charAt(right))) {
+                charSet.remove(s.charAt(left));
+                left++;
+            }
+            charSet.add(s.charAt(right));
+            maxLength = Math.max(maxLength, right - left + 1);
+        }
+
+        return maxLength;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java b/src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java
new file mode 100644
index 000000000000..8638a707a3e2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.slidingwindow;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the LongestSubstringWithoutRepeatingCharacters class.
+ *
+ * @author  (https://github.com/Chiefpatwal)
+ */
+public class LongestSubstringWithoutRepeatingCharactersTest {
+
+    @Test
+    public void testLengthOfLongestSubstring() {
+        // Test cases for the lengthOfLongestSubstring method
+        assertEquals(3, LongestSubstringWithoutRepeatingCharacters.lengthOfLongestSubstring("abcabcbb"));
+        assertEquals(1, LongestSubstringWithoutRepeatingCharacters.lengthOfLongestSubstring("bbbbb"));
+        assertEquals(3, LongestSubstringWithoutRepeatingCharacters.lengthOfLongestSubstring("pwwkew"));
+        assertEquals(0, LongestSubstringWithoutRepeatingCharacters.lengthOfLongestSubstring(""));
+        assertEquals(5, LongestSubstringWithoutRepeatingCharacters.lengthOfLongestSubstring("abcde"));
+    }
+}

From 6684a6993e4cbe30c6ff77839be73e5c542f1f97 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 11:28:11 +0530
Subject: [PATCH 0623/1338] Enhance docs, add tests in `StackOfLinkedList`
 (#6021)

---
 DIRECTORY.md                                  |   4 +-
 .../stacks/StackOfLinkedList.java             |  94 +++++++-------
 .../stacks/LinkedListStackTest.java           |  71 ----------
 .../stacks/StackOfLinkedListTest.java         | 121 ++++++++++++++++++
 4 files changed, 167 insertions(+), 123 deletions(-)
 delete mode 100644 src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 98fbec625f5f..2a6bf70c7632 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -571,6 +571,7 @@
             * [UnionFind](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UnionFind.java)
             * [UpperBound](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UpperBound.java)
           * slidingwindow
+            * [LongestSubstringWithoutRepeatingCharacters](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java)
             * [MaxSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java)
           * sorts
             * [AdaptiveMergeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java)
@@ -855,9 +856,9 @@
               * [QueueByTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java)
               * [QueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java)
             * stacks
-              * [LinkedListStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java)
               * [StackArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java)
               * [StackArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java)
+              * [StackOfLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java)
             * trees
               * [BinaryTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java)
               * [BoundaryTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BoundaryTraversalTest.java)
@@ -1163,6 +1164,7 @@
             * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java)
             * [UpperBoundTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UpperBoundTest.java)
           * slidingwindow
+            * [LongestSubstringWithoutRepeatingCharactersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java)
             * [MaxSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java)
           * sorts
             * [AdaptiveMergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java b/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java
index 52b1c1d86c94..c12097dfa28c 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java
@@ -3,35 +3,20 @@
 import java.util.NoSuchElementException;
 
 /**
- * @author Varun Upadhyay (https://github.com/varunu28)
+ * A stack implementation using a singly linked list.
+ *
+ * <p>This class provides methods to push, pop, and peek elements in a Last-In-First-Out (LIFO) manner.
+ * It keeps track of the number of elements in the stack and allows checking if the stack is empty.
+ *
+ * <p>This implementation does not allow null elements to be pushed onto the stack.
  */
-// An implementation of a Stack using a Linked List
 final class StackOfLinkedList {
     private StackOfLinkedList() {
     }
-
-    public static void main(String[] args) {
-        LinkedListStack stack = new LinkedListStack();
-        stack.push(1);
-        stack.push(2);
-        stack.push(3);
-        stack.push(4);
-        stack.push(5);
-
-        System.out.println(stack);
-
-        System.out.println("Size of stack currently is: " + stack.getSize());
-
-        assert stack.pop() == 5;
-        assert stack.pop() == 4;
-
-        System.out.println("Top element of stack currently is: " + stack.peek());
-    }
 }
 
-// A node class
+// A node class for the linked list
 class Node {
-
     public int data;
     public Node next;
 
@@ -42,25 +27,24 @@ class Node {
 }
 
 /**
- * A class which implements a stack using a linked list
+ * A class that implements a stack using a linked list.
  *
- * <p>
- * Contains all the stack methods : push, pop, printStack, isEmpty
+ * <p>This stack supports basic operations:
+ * <ul>
+ * <li>push: Adds an element to the top of the stack</li>
+ * <li>pop: Removes and returns the top element of the stack</li>
+ * <li>peek: Returns the top element without removing it</li>
+ * <li>isEmpty: Checks if the stack is empty</li>
+ * <li>getSize: Returns the current size of the stack</li>
+ * </ul>
  */
 class LinkedListStack {
 
-    /**
-     * Top of stack
-     */
-    Node head;
+    private Node head; // Top of the stack
+    private int size; // Number of elements in the stack
 
     /**
-     * Size of stack
-     */
-    private int size;
-
-    /**
-     * Init properties
+     * Initializes an empty stack.
      */
     LinkedListStack() {
         head = null;
@@ -68,10 +52,10 @@ class LinkedListStack {
     }
 
     /**
-     * Add element at top
+     * Adds an element to the top of the stack.
      *
-     * @param x to be added
-     * @return <tt>true</tt> if add successfully
+     * @param x the element to be added
+     * @return <tt>true</tt> if the element is added successfully
      */
     public boolean push(int x) {
         Node newNode = new Node(x);
@@ -82,10 +66,10 @@ public boolean push(int x) {
     }
 
     /**
-     * Pop element at top of stack
+     * Removes and returns the top element of the stack.
      *
-     * @return element at top of stack
-     * @throws NoSuchElementException if stack is empty
+     * @return the element at the top of the stack
+     * @throws NoSuchElementException if the stack is empty
      */
     public int pop() {
         if (size == 0) {
@@ -94,20 +78,20 @@ public int pop() {
         Node destroy = head;
         head = head.next;
         int retValue = destroy.data;
-        destroy = null; // clear to let GC do it's work
+        destroy = null; // Help garbage collection
         size--;
         return retValue;
     }
 
     /**
-     * Peek element at top of stack
+     * Returns the top element of the stack without removing it.
      *
-     * @return element at top of stack
-     * @throws NoSuchElementException if stack is empty
+     * @return the element at the top of the stack
+     * @throws NoSuchElementException if the stack is empty
      */
     public int peek() {
         if (size == 0) {
-            throw new NoSuchElementException("Empty stack. Nothing to pop");
+            throw new NoSuchElementException("Empty stack. Nothing to peek");
         }
         return head.data;
     }
@@ -120,24 +104,32 @@ public String toString() {
             builder.append(cur.data).append("->");
             cur = cur.next;
         }
-        return builder.replace(builder.length() - 2, builder.length(), "").toString();
+        return builder.replace(builder.length() - 2, builder.length(), "").toString(); // Remove the last "->"
     }
 
     /**
-     * Check if stack is empty
+     * Checks if the stack is empty.
      *
-     * @return <tt>true</tt> if stack is empty, otherwise <tt>false</tt>
+     * @return <tt>true</tt> if the stack is empty, <tt>false</tt> otherwise
      */
     public boolean isEmpty() {
         return size == 0;
     }
 
     /**
-     * Return size of stack
+     * Returns the current size of the stack.
      *
-     * @return size of stack
+     * @return the number of elements in the stack
      */
     public int getSize() {
         return size;
     }
+
+    /**
+     * Removes all elements from the stack.
+     */
+    public void makeEmpty() {
+        head = null;
+        size = 0;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java
deleted file mode 100644
index 8c3689a79729..000000000000
--- a/src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java
+++ /dev/null
@@ -1,71 +0,0 @@
-package com.thealgorithms.datastructures.stacks;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
-import java.util.NoSuchElementException;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-
-public class LinkedListStackTest {
-
-    private LinkedListStack stack;
-
-    @BeforeEach
-    public void setUp() {
-        stack = new LinkedListStack();
-    }
-
-    @Test
-    public void testPushAndPeek() {
-        stack.push(1);
-        stack.push(2);
-        stack.push(3);
-
-        assertEquals(3, stack.peek());
-        assertEquals(3, stack.getSize());
-    }
-
-    @Test
-    public void testPop() {
-        stack.push(1);
-        stack.push(2);
-        stack.push(3);
-
-        assertEquals(3, stack.pop());
-        assertEquals(2, stack.pop());
-        assertEquals(1, stack.pop());
-        assertTrue(stack.isEmpty());
-    }
-
-    @Test
-    public void testPopEmptyStack() {
-        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, () -> stack.pop());
-    }
-
-    @Test
-    public void testPeekEmptyStack() {
-        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, () -> stack.peek());
-    }
-
-    @Test
-    public void testIsEmpty() {
-        assertTrue(stack.isEmpty());
-
-        stack.push(1);
-        assertFalse(stack.isEmpty());
-
-        stack.pop();
-        assertTrue(stack.isEmpty());
-    }
-
-    @Test
-    public void testToString() {
-        stack.push(1);
-        stack.push(2);
-        stack.push(3);
-
-        assertEquals("3->2->1", stack.toString());
-    }
-}
diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java
new file mode 100644
index 000000000000..58af66bc38f4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java
@@ -0,0 +1,121 @@
+package com.thealgorithms.datastructures.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.NoSuchElementException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class StackOfLinkedListTest {
+
+    private LinkedListStack stack;
+
+    @BeforeEach
+    public void setUp() {
+        stack = new LinkedListStack();
+    }
+
+    @Test
+    public void testPushAndPeek() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+
+        assertEquals(3, stack.peek(), "Peek should return the last pushed value");
+        assertEquals(3, stack.getSize(), "Size should reflect the number of elements");
+    }
+
+    @Test
+    public void testPop() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+
+        assertEquals(3, stack.pop(), "Pop should return the last pushed value");
+        assertEquals(2, stack.pop(), "Pop should return the next last pushed value");
+        assertEquals(1, stack.pop(), "Pop should return the first pushed value");
+        assertTrue(stack.isEmpty(), "Stack should be empty after popping all elements");
+    }
+
+    @Test
+    public void testPopEmptyStack() {
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, () -> stack.pop(), "Popping from an empty stack should throw NoSuchElementException");
+    }
+
+    @Test
+    public void testPeekEmptyStack() {
+        org.junit.jupiter.api.Assertions.assertThrows(NoSuchElementException.class, () -> stack.peek(), "Peeking into an empty stack should throw NoSuchElementException");
+    }
+
+    @Test
+    public void testIsEmpty() {
+        assertTrue(stack.isEmpty(), "Newly created stack should be empty");
+
+        stack.push(1);
+        assertFalse(stack.isEmpty(), "Stack should not be empty after pushing an element");
+
+        stack.pop();
+        assertTrue(stack.isEmpty(), "Stack should be empty after popping the only element");
+    }
+
+    @Test
+    public void testToString() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+
+        assertEquals("3->2->1", stack.toString(), "String representation of stack should match the expected format");
+    }
+
+    @Test
+    public void testMultiplePushesAndPops() {
+        stack.push(5);
+        stack.push(10);
+        stack.push(15);
+
+        assertEquals(15, stack.pop(), "Pop should return the last pushed value");
+        assertEquals(10, stack.peek(), "Peek should return the new top value after popping");
+        assertEquals(10, stack.pop(), "Pop should return the next last pushed value");
+        assertEquals(5, stack.pop(), "Pop should return the first pushed value");
+        assertTrue(stack.isEmpty(), "Stack should be empty after popping all elements");
+    }
+
+    @Test
+    public void testGetSize() {
+        assertEquals(0, stack.getSize(), "Size of an empty stack should be zero");
+        stack.push(1);
+        stack.push(2);
+        assertEquals(2, stack.getSize(), "Size should reflect the number of elements");
+        stack.pop();
+        assertEquals(1, stack.getSize(), "Size should decrease with each pop");
+    }
+
+    @Test
+    public void testSizeAfterClearingStack() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+
+        // Manually clear the stack
+        while (!stack.isEmpty()) {
+            stack.pop();
+        }
+        assertTrue(stack.isEmpty(), "Stack should be empty after clearing");
+        assertEquals(0, stack.getSize(), "Size should be zero after clearing the stack");
+    }
+
+    @Test
+    public void testSequentialPushAndPop() {
+        for (int i = 1; i <= 100; i++) {
+            stack.push(i);
+        }
+        assertEquals(100, stack.getSize(), "Size should be 100 after pushing 100 elements");
+
+        for (int i = 100; i >= 1; i--) {
+            assertEquals(i, stack.pop(), "Popping should return values in LIFO order");
+        }
+        assertTrue(stack.isEmpty(), "Stack should be empty after popping all elements");
+    }
+}

From 3a30e4831537ed50f574a99df33815a01f711ca9 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 11:31:27 +0530
Subject: [PATCH 0624/1338] Enhance docs, add tests in `MinPriorityQueue`
 (#5986)

---
 DIRECTORY.md                                  |   1 +
 .../heaps/MinPriorityQueue.java               | 145 ++++++++++--------
 .../heaps/MinPriorityQueueTest.java           |  87 +++++++++++
 3 files changed, 172 insertions(+), 61 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 2a6bf70c7632..ee1b9dcd8b11 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -833,6 +833,7 @@
               * [FibonacciHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
               * [GenericHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java)
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
+              * [MinPriorityQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java)
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
               * [CountSinglyLinkedListRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java b/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java
index 9d19e9aaee1a..a1360b14dc5a 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java
@@ -1,16 +1,23 @@
 package com.thealgorithms.datastructures.heaps;
 
 /**
- * Minimum Priority Queue It is a part of heap data structure A heap is a
- * specific tree based data structure in which all the nodes of tree are in a
- * specific order. that is the children are arranged in some respect of their
- * parents, can either be greater or less than the parent. This makes it a min
- * priority queue or max priority queue.
+ * A MinPriorityQueue is a specialized data structure that maintains the
+ * min-heap property, where the smallest element has the highest priority.
  *
- * <p>
+ * <p>In a min-priority queue, every parent node is less than or equal
+ * to its child nodes, which ensures that the smallest element can
+ * always be efficiently retrieved.</p>
  *
- * <p>
- * Functions: insert, delete, peek, isEmpty, print, heapSort, sink
+ * <p>Functions:</p>
+ * <ul>
+ *     <li><b>insert(int key)</b>: Inserts a new key into the queue.</li>
+ *     <li><b>delete()</b>: Removes and returns the highest priority value (the minimum).</li>
+ *     <li><b>peek()</b>: Returns the highest priority value without removing it.</li>
+ *     <li><b>isEmpty()</b>: Checks if the queue is empty.</li>
+ *     <li><b>isFull()</b>: Checks if the queue is full.</li>
+ *     <li><b>heapSort()</b>: Sorts the elements in ascending order.</li>
+ *     <li><b>print()</b>: Prints the current elements in the queue.</li>
+ * </ul>
  */
 public class MinPriorityQueue {
 
@@ -18,18 +25,25 @@ public class MinPriorityQueue {
     private final int capacity;
     private int size;
 
-    // class the constructor and initializes the capacity
-    MinPriorityQueue(int c) {
+    /**
+     * Initializes a new MinPriorityQueue with a specified capacity.
+     *
+     * @param c the maximum number of elements the queue can hold
+     */
+    public MinPriorityQueue(int c) {
         this.capacity = c;
         this.size = 0;
         this.heap = new int[c + 1];
     }
 
-    // inserts the key at the end and rearranges it
-    // so that the binary heap is in appropriate order
+    /**
+     * Inserts a new key into the min-priority queue.
+     *
+     * @param key the value to be inserted
+     */
     public void insert(int key) {
         if (this.isFull()) {
-            return;
+            throw new IllegalStateException("MinPriorityQueue is full. Cannot insert new element.");
         }
         this.heap[this.size + 1] = key;
         int k = this.size + 1;
@@ -44,89 +58,98 @@ public void insert(int key) {
         this.size++;
     }
 
-    // returns the highest priority value
+    /**
+     * Retrieves the highest priority value (the minimum) without removing it.
+     *
+     * @return the minimum value in the queue
+     * @throws IllegalStateException if the queue is empty
+     */
     public int peek() {
+        if (isEmpty()) {
+            throw new IllegalStateException("MinPriorityQueue is empty. Cannot peek.");
+        }
         return this.heap[1];
     }
 
-    // returns boolean value whether the heap is empty or not
+    /**
+     * Checks whether the queue is empty.
+     *
+     * @return true if the queue is empty, false otherwise
+     */
     public boolean isEmpty() {
-        return 0 == this.size;
+        return size == 0;
     }
 
-    // returns boolean value whether the heap is full or not
+    /**
+     * Checks whether the queue is full.
+     *
+     * @return true if the queue is full, false otherwise
+     */
     public boolean isFull() {
-        return this.size == this.capacity;
+        return size == capacity;
     }
 
-    // prints the heap
+    /**
+     * Prints the elements of the queue.
+     */
     public void print() {
-        for (int i = 1; i <= this.capacity; i++) {
+        for (int i = 1; i <= this.size; i++) {
             System.out.print(this.heap[i] + " ");
         }
         System.out.println();
     }
 
-    // heap sorting can be done by performing
-    // delete function to the number of times of the size of the heap
-    // it returns reverse sort because it is a min priority queue
+    /**
+     * Sorts the elements in the queue using heap sort.
+     */
     public void heapSort() {
-        for (int i = 1; i < this.capacity; i++) {
+        for (int i = 1; i <= this.size; i++) {
             this.delete();
         }
     }
 
-    // this function reorders the heap after every delete function
+    /**
+     * Reorders the heap after a deletion to maintain the heap property.
+     */
     private void sink() {
         int k = 1;
-        while (2 * k <= this.size || 2 * k + 1 <= this.size) {
-            int minIndex;
-            if (this.heap[2 * k] >= this.heap[k]) {
-                if (2 * k + 1 <= this.size && this.heap[2 * k + 1] >= this.heap[k]) {
-                    break;
-                } else if (2 * k + 1 > this.size) {
-                    break;
-                }
+        while (2 * k <= this.size) {
+            int minIndex = k; // Assume current index is the minimum
+
+            if (2 * k <= this.size && this.heap[2 * k] < this.heap[minIndex]) {
+                minIndex = 2 * k; // Left child is smaller
             }
-            if (2 * k + 1 > this.size) {
-                minIndex = this.heap[2 * k] < this.heap[k] ? 2 * k : k;
-            } else {
-                if (this.heap[k] > this.heap[2 * k] || this.heap[k] > this.heap[2 * k + 1]) {
-                    minIndex = this.heap[2 * k] < this.heap[2 * k + 1] ? 2 * k : 2 * k + 1;
-                } else {
-                    minIndex = k;
-                }
+            if (2 * k + 1 <= this.size && this.heap[2 * k + 1] < this.heap[minIndex]) {
+                minIndex = 2 * k + 1; // Right child is smaller
             }
+
+            if (minIndex == k) {
+                break; // No swap needed, heap property is satisfied
+            }
+
+            // Swap with the smallest child
             int temp = this.heap[k];
             this.heap[k] = this.heap[minIndex];
             this.heap[minIndex] = temp;
-            k = minIndex;
+
+            k = minIndex; // Move down to the smallest child
         }
     }
 
-    // deletes the highest priority value from the heap
+    /**
+     * Deletes and returns the highest priority value (the minimum) from the queue.
+     *
+     * @return the minimum value from the queue
+     * @throws IllegalStateException if the queue is empty
+     */
     public int delete() {
+        if (isEmpty()) {
+            throw new IllegalStateException("MinPriorityQueue is empty. Cannot delete.");
+        }
         int min = this.heap[1];
-        this.heap[1] = this.heap[this.size];
-        this.heap[this.size] = min;
+        this.heap[1] = this.heap[this.size]; // Move last element to the root
         this.size--;
         this.sink();
         return min;
     }
-
-    public static void main(String[] args) {
-        // testing
-        MinPriorityQueue q = new MinPriorityQueue(8);
-        q.insert(5);
-        q.insert(2);
-        q.insert(4);
-        q.insert(1);
-        q.insert(7);
-        q.insert(6);
-        q.insert(3);
-        q.insert(8);
-        q.print(); // [ 1, 2, 3, 5, 7, 6, 4, 8 ]
-        q.heapSort();
-        q.print(); // [ 8, 7, 6, 5, 4, 3, 2, 1 ]
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java
new file mode 100644
index 000000000000..8f93bd630aa7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java
@@ -0,0 +1,87 @@
+package com.thealgorithms.datastructures.heaps;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class MinPriorityQueueTest {
+
+    @Test
+    void testInsertAndPeek() {
+        MinPriorityQueue queue = new MinPriorityQueue(5);
+        queue.insert(10);
+        queue.insert(5);
+        queue.insert(15);
+
+        Assertions.assertEquals(5, queue.peek(), "The minimum element should be 5.");
+    }
+
+    @Test
+    void testDelete() {
+        MinPriorityQueue queue = new MinPriorityQueue(5);
+        queue.insert(10);
+        queue.insert(5);
+        queue.insert(15);
+
+        Assertions.assertEquals(5, queue.delete(), "The deleted minimum element should be 5.");
+        Assertions.assertEquals(10, queue.peek(), "After deletion, the new minimum should be 10.");
+    }
+
+    @Test
+    void testIsEmpty() {
+        MinPriorityQueue queue = new MinPriorityQueue(5);
+        Assertions.assertTrue(queue.isEmpty(), "The queue should be empty initially.");
+
+        queue.insert(10);
+        Assertions.assertFalse(queue.isEmpty(), "The queue should not be empty after insertion.");
+    }
+
+    @Test
+    void testIsFull() {
+        MinPriorityQueue queue = new MinPriorityQueue(2);
+        queue.insert(10);
+        queue.insert(5);
+
+        Assertions.assertTrue(queue.isFull(), "The queue should be full after inserting two elements.");
+        queue.delete();
+        Assertions.assertFalse(queue.isFull(), "The queue should not be full after deletion.");
+    }
+
+    @Test
+    void testHeapSort() {
+        MinPriorityQueue queue = new MinPriorityQueue(5);
+        queue.insert(10);
+        queue.insert(5);
+        queue.insert(15);
+        queue.insert(1);
+        queue.insert(3);
+
+        // Delete all elements to sort the queue
+        int[] sortedArray = new int[5];
+        for (int i = 0; i < 5; i++) {
+            sortedArray[i] = queue.delete();
+        }
+
+        Assertions.assertArrayEquals(new int[] {1, 3, 5, 10, 15}, sortedArray, "The array should be sorted in ascending order.");
+    }
+
+    @Test
+    void testPeekEmptyQueue() {
+        MinPriorityQueue queue = new MinPriorityQueue(5);
+        Assertions.assertThrows(IllegalStateException.class, queue::peek, "Should throw an exception when peeking into an empty queue.");
+    }
+
+    @Test
+    void testDeleteEmptyQueue() {
+        MinPriorityQueue queue = new MinPriorityQueue(5);
+        Assertions.assertThrows(IllegalStateException.class, queue::delete, "Should throw an exception when deleting from an empty queue.");
+    }
+
+    @Test
+    void testInsertWhenFull() {
+        MinPriorityQueue queue = new MinPriorityQueue(2);
+        queue.insert(10);
+        queue.insert(5);
+
+        Assertions.assertThrows(IllegalStateException.class, () -> queue.insert(15), "Should throw an exception when inserting into a full queue.");
+    }
+}

From e0ab1d357c34de9e68275fc9c71a42d029377c76 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 11:35:27 +0530
Subject: [PATCH 0625/1338] Add `OptimalFileMerging` algorithm (#5805)

---
 DIRECTORY.md                                  |  2 +
 .../greedyalgorithms/OptimalFileMerging.java  | 52 +++++++++++++++++++
 .../OptimalFileMergingTest.java               | 22 ++++++++
 3 files changed, 76 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index ee1b9dcd8b11..d2badd76029c 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -328,6 +328,7 @@
             * [MergeIntervals](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java)
             * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java)
             * [MinimumWaitingTime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTime.java)
+            * [OptimalFileMerging](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java)
             * [StockProfitCalculator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java)
           * io
             * [BufferedReader](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/io/BufferedReader.java)
@@ -956,6 +957,7 @@
             * [MergeIntervalsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java)
             * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java)
             * [MinimumWaitingTimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTimeTest.java)
+            * [OptimalFileMergingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java)
             * [StockProfitCalculatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java)
           * io
             * [BufferedReaderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/io/BufferedReaderTest.java)
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java b/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java
new file mode 100644
index 000000000000..7a1f2edf8180
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java
@@ -0,0 +1,52 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.PriorityQueue;
+
+/**
+ * Class to solve the Optimal File Merging Problem.
+ * The goal is to minimize the cost of merging files, where the cost of merging two files is the sum of their sizes.
+ * The cost of merging all files is the sum of the costs of merging each pair of files.
+ * Example:
+ * files = [4, 3, 2, 6]
+ * The minimum cost to merge all files is 29.
+ * Steps:
+ * 1. Merge files 2 and 3 (cost = 2 + 3 = 5). New files = [4, 5, 6]
+ * 2. Merge files 4 and 5 (cost = 4 + 5 = 9). New files = [6, 9]
+ * 3. Merge files 6 and 9 (cost = 6 + 9 = 15). New files = [15]
+ * Total cost = 5 + 9 + 15 = 29
+ *
+ * @author Hardvan
+ */
+public final class OptimalFileMerging {
+    private OptimalFileMerging() {
+    }
+
+    /**
+     * Calculates the minimum cost to merge all files.
+     * Steps:
+     * 1. Add all files to a min heap.
+     * 2. Remove the two smallest files from the heap, merge them, and add the result back to the heap.
+     * 3. Repeat step 2 until there is only one file left in the heap.
+     * 4. The total cost is the sum of all the costs of merging the files.
+     *
+     * @param files array of file sizes
+     * @return the minimum cost to merge the files
+     */
+    public static int minMergeCost(int[] files) {
+        PriorityQueue<Integer> minHeap = new PriorityQueue<>();
+        for (int file : files) {
+            minHeap.add(file);
+        }
+
+        int totalCost = 0;
+        while (minHeap.size() > 1) {
+            int first = minHeap.poll();
+            int second = minHeap.poll();
+            int cost = first + second;
+            totalCost += cost;
+
+            minHeap.add(cost);
+        }
+        return totalCost;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java
new file mode 100644
index 000000000000..9ff2b95ff2e5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class OptimalFileMergingTest {
+
+    @ParameterizedTest
+    @MethodSource("fileMergingProvider")
+    public void testMinMergeCost(int[] files, int expected) {
+        assertEquals(expected, OptimalFileMerging.minMergeCost(files));
+    }
+
+    private static Stream<Arguments> fileMergingProvider() {
+        return Stream.of(Arguments.of(new int[] {4, 3, 2, 6}, 29), Arguments.of(new int[] {5}, 0), Arguments.of(new int[] {2, 2, 2}, 10), Arguments.of(new int[] {10, 5, 3, 2}, 35), Arguments.of(new int[] {1, 1, 1, 1}, 8), Arguments.of(new int[] {1, 2, 3, 4, 5}, 33),
+            Arguments.of(new int[] {1, 2, 3, 4, 5, 6}, 51), Arguments.of(new int[] {1, 2, 3, 4, 5, 6, 7}, 74), Arguments.of(new int[] {1, 2, 3, 4, 5, 6, 7, 8}, 102), Arguments.of(new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9}, 135));
+    }
+}

From c40eb8dbac618973d582af5d2a474dbebb2f6c90 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 11:45:24 +0530
Subject: [PATCH 0626/1338] Add `KCenters` algorithm (#5806)

---
 DIRECTORY.md                                  |  2 +
 .../greedyalgorithms/KCenters.java            | 62 +++++++++++++++++++
 .../greedyalgorithms/KCentersTest.java        | 15 +++++
 3 files changed, 79 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/KCenters.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/KCentersTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index d2badd76029c..78ff31bf910f 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -325,6 +325,7 @@
             * [FractionalKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
             * [GaleShapley](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java)
             * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
+            * [KCenters](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/KCenters.java)
             * [MergeIntervals](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java)
             * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java)
             * [MinimumWaitingTime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTime.java)
@@ -954,6 +955,7 @@
             * [FractionalKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
             * [GaleShapleyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java)
             * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
+            * [KCentersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/KCentersTest.java)
             * [MergeIntervalsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java)
             * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java)
             * [MinimumWaitingTimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTimeTest.java)
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/KCenters.java b/src/main/java/com/thealgorithms/greedyalgorithms/KCenters.java
new file mode 100644
index 000000000000..152b36053345
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/KCenters.java
@@ -0,0 +1,62 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.Arrays;
+
+/**
+ * Given a set of points and a number k.
+ * The goal is to minimize the maximum distance between any point and its nearest center.
+ * Each point is assigned to the nearest center.
+ * The distance between two points is the Euclidean distance.
+ * The problem is NP-hard.
+ *
+ * @author Hardvan
+ */
+public final class KCenters {
+    private KCenters() {
+    }
+
+    /**
+     * Finds the maximum distance to the nearest center given k centers.
+     * Steps:
+     * 1. Initialize an array {@code selected} of size n and an array {@code maxDist} of size n.
+     * 2. Set the first node as selected and update the maxDist array.
+     * 3. For each center, find the farthest node from the selected centers.
+     * 4. Update the maxDist array.
+     * 5. Return the maximum distance to the nearest center.
+     *
+     * @param distances matrix representing distances between nodes
+     * @param k         the number of centers
+     * @return the maximum distance to the nearest center
+     */
+    public static int findKCenters(int[][] distances, int k) {
+        int n = distances.length;
+        boolean[] selected = new boolean[n];
+        int[] maxDist = new int[n];
+
+        Arrays.fill(maxDist, Integer.MAX_VALUE);
+
+        selected[0] = true;
+        for (int i = 1; i < n; i++) {
+            maxDist[i] = Math.min(maxDist[i], distances[0][i]);
+        }
+
+        for (int centers = 1; centers < k; centers++) {
+            int farthest = -1;
+            for (int i = 0; i < n; i++) {
+                if (!selected[i] && (farthest == -1 || maxDist[i] > maxDist[farthest])) {
+                    farthest = i;
+                }
+            }
+            selected[farthest] = true;
+            for (int i = 0; i < n; i++) {
+                maxDist[i] = Math.min(maxDist[i], distances[farthest][i]);
+            }
+        }
+
+        int result = 0;
+        for (int dist : maxDist) {
+            result = Math.max(result, dist);
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/KCentersTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/KCentersTest.java
new file mode 100644
index 000000000000..9202d3467f0c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/KCentersTest.java
@@ -0,0 +1,15 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class KCentersTest {
+
+    @Test
+    public void testFindKCenters() {
+        int[][] distances = {{0, 2, 3, 4}, {2, 0, 5, 1}, {3, 5, 0, 7}, {4, 1, 7, 0}};
+        assertEquals(4, KCenters.findKCenters(distances, 2));
+        assertEquals(2, KCenters.findKCenters(distances, 4));
+    }
+}

From 6545688555122fb37ec02ed76534097fac20bae6 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 11:48:56 +0530
Subject: [PATCH 0627/1338] Enhance docs, add tests in `CircularQueue` (#6015)

---
 .../datastructures/queues/CircularQueue.java  | 99 +++++++++++++------
 .../queues/CircularQueueTest.java             | 66 +++++++++++++
 2 files changed, 134 insertions(+), 31 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
index c67817a6f2d4..74ee06ca92e4 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java
@@ -1,7 +1,27 @@
 package com.thealgorithms.datastructures.queues;
 
-// This program implements the concept of CircularQueue in Java
-// Link to the concept: (https://en.wikipedia.org/wiki/Circular_buffer)
+/**
+ * The CircularQueue class represents a generic circular queue data structure that uses an array to
+ * store elements. This queue allows efficient utilization of space by wrapping around the array,
+ * thus avoiding the need to shift elements during enqueue and dequeue operations.
+ *
+ * <p>When the queue reaches its maximum capacity, further enqueues will raise an exception.
+ * Similarly, attempts to dequeue or peek from an empty queue will also result in an exception.
+ *
+ * <p>Reference: <a href="https://en.wikipedia.org/wiki/Circular_buffer">Circular Buffer</a>
+ *
+ * <p>Usage Example:
+ * <pre>
+ *     CircularQueue<Integer> queue = new CircularQueue<>(3);
+ *     queue.enQueue(1);
+ *     queue.enQueue(2);
+ *     queue.enQueue(3);
+ *     queue.deQueue(); // Removes 1
+ *     queue.enQueue(4); // Wraps around and places 4 at the position of removed 1
+ * </pre>
+ *
+ * @param <T> the type of elements in this queue
+ */
 public class CircularQueue<T> {
     private T[] array;
     private int topOfQueue;
@@ -9,8 +29,17 @@ public class CircularQueue<T> {
     private final int size;
     private int currentSize;
 
+    /**
+     * Constructs a CircularQueue with a specified capacity.
+     *
+     * @param size the maximum number of elements this queue can hold
+     * @throws IllegalArgumentException if the size is less than 1
+     */
     @SuppressWarnings("unchecked")
     public CircularQueue(int size) {
+        if (size < 1) {
+            throw new IllegalArgumentException("Size must be greater than 0");
+        }
         this.array = (T[]) new Object[size];
         this.topOfQueue = -1;
         this.beginningOfQueue = -1;
@@ -18,14 +47,30 @@ public CircularQueue(int size) {
         this.currentSize = 0;
     }
 
+    /**
+     * Checks if the queue is empty.
+     *
+     * @return {@code true} if the queue is empty; {@code false} otherwise
+     */
     public boolean isEmpty() {
         return currentSize == 0;
     }
 
+    /**
+     * Checks if the queue is full.
+     *
+     * @return {@code true} if the queue has reached its maximum capacity; {@code false} otherwise
+     */
     public boolean isFull() {
         return currentSize == size;
     }
 
+    /**
+     * Adds a new element to the queue. If the queue is full, an exception is thrown.
+     *
+     * @param value the element to be added to the queue
+     * @throws IllegalStateException if the queue is already full
+     */
     public void enQueue(T value) {
         if (isFull()) {
             throw new IllegalStateException("Queue is full");
@@ -38,12 +83,18 @@ public void enQueue(T value) {
         currentSize++;
     }
 
+    /**
+     * Removes and returns the element at the front of the queue.
+     *
+     * @return the element at the front of the queue
+     * @throws IllegalStateException if the queue is empty
+     */
     public T deQueue() {
         if (isEmpty()) {
             throw new IllegalStateException("Queue is empty");
         }
         T removedValue = array[beginningOfQueue];
-        array[beginningOfQueue] = null; // Optional: Help GC
+        array[beginningOfQueue] = null; // Optional: Nullify to help garbage collection
         beginningOfQueue = (beginningOfQueue + 1) % size;
         currentSize--;
         if (isEmpty()) {
@@ -53,6 +104,12 @@ public T deQueue() {
         return removedValue;
     }
 
+    /**
+     * Returns the element at the front of the queue without removing it.
+     *
+     * @return the element at the front of the queue
+     * @throws IllegalStateException if the queue is empty
+     */
     public T peek() {
         if (isEmpty()) {
             throw new IllegalStateException("Queue is empty");
@@ -60,6 +117,9 @@ public T peek() {
         return array[beginningOfQueue];
     }
 
+    /**
+     * Deletes the entire queue by resetting all elements and pointers.
+     */
     public void deleteQueue() {
         array = null;
         beginningOfQueue = -1;
@@ -67,35 +127,12 @@ public void deleteQueue() {
         currentSize = 0;
     }
 
+    /**
+     * Returns the current number of elements in the queue.
+     *
+     * @return the number of elements currently in the queue
+     */
     public int size() {
         return currentSize;
     }
-
-    public static void main(String[] args) {
-        CircularQueue<Integer> cq = new CircularQueue<>(5);
-        System.out.println(cq.isEmpty()); // true
-        System.out.println(cq.isFull()); // false
-        cq.enQueue(1);
-        cq.enQueue(2);
-        cq.enQueue(3);
-        cq.enQueue(4);
-        cq.enQueue(5);
-
-        System.out.println(cq.deQueue()); // 1
-        System.out.println(cq.deQueue()); // 2
-        System.out.println(cq.deQueue()); // 3
-        System.out.println(cq.deQueue()); // 4
-        System.out.println(cq.deQueue()); // 5
-
-        System.out.println(cq.isFull()); // false
-        System.out.println(cq.isEmpty()); // true
-        cq.enQueue(6);
-        cq.enQueue(7);
-        cq.enQueue(8);
-
-        System.out.println(cq.peek()); // 6
-        System.out.println(cq.peek()); // 6
-
-        cq.deleteQueue();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java b/src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java
index 71dca8fdb538..55ce9995a32d 100644
--- a/src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java
@@ -103,4 +103,70 @@ void testSize() {
         cq.deQueue();
         assertEquals(1, cq.size());
     }
+
+    @Test
+    void testCircularWrapAround() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+        cq.enQueue(3);
+
+        cq.deQueue();
+        cq.enQueue(4);
+
+        assertEquals(2, cq.deQueue());
+        assertEquals(3, cq.deQueue());
+        assertEquals(4, cq.deQueue());
+        assertTrue(cq.isEmpty());
+    }
+
+    @Test
+    void testEnQueueDeQueueMultipleTimes() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.enQueue(2);
+        cq.deQueue();
+        cq.enQueue(3);
+        cq.enQueue(4);
+
+        assertTrue(cq.isFull());
+        assertEquals(2, cq.deQueue());
+        assertEquals(3, cq.deQueue());
+        assertEquals(4, cq.deQueue());
+        assertTrue(cq.isEmpty());
+    }
+
+    @Test
+    void testMultipleWrapArounds() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        cq.enQueue(1);
+        cq.deQueue();
+        cq.enQueue(2);
+        cq.deQueue();
+        cq.enQueue(3);
+        cq.deQueue();
+        cq.enQueue(4);
+
+        assertEquals(4, cq.peek());
+    }
+
+    @Test
+    void testSizeDuringOperations() {
+        CircularQueue<Integer> cq = new CircularQueue<>(3);
+        assertEquals(0, cq.size());
+
+        cq.enQueue(1);
+        cq.enQueue(2);
+        assertEquals(2, cq.size());
+
+        cq.deQueue();
+        assertEquals(1, cq.size());
+
+        cq.enQueue(3);
+        cq.enQueue(4);
+        assertEquals(3, cq.size());
+        cq.deQueue();
+        cq.deQueue();
+        assertEquals(1, cq.size());
+    }
 }

From 2083d68daea2fea329a0946993c15ad77095076e Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 11:53:14 +0530
Subject: [PATCH 0628/1338] Enhance docs, add tests in `StackArrayList` (#6020)

---
 .../datastructures/stacks/StackArrayList.java | 41 ++++++++++++-
 .../stacks/StackArrayListTest.java            | 57 ++++++++++++++-----
 2 files changed, 83 insertions(+), 15 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java b/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java
index 088156a98f78..bd400adea317 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java
@@ -4,23 +4,41 @@
 import java.util.EmptyStackException;
 
 /**
- * This class implements a Stack using an ArrayList.
+ * A stack implementation backed by an {@link ArrayList}, offering dynamic resizing
+ * and LIFO (Last-In-First-Out) behavior.
  *
- * @param <T> the type of elements in this stack
+ * <p>The stack grows dynamically as elements are added, and elements are removed
+ * in reverse order of their addition.
+ *
+ * @param <T> the type of elements stored in this stack
  */
 public class StackArrayList<T> implements Stack<T> {
 
     private final ArrayList<T> stack;
 
+    /**
+     * Constructs an empty stack.
+     */
     public StackArrayList() {
         stack = new ArrayList<>();
     }
 
+    /**
+     * Adds an element to the top of the stack.
+     *
+     * @param value the element to be added
+     */
     @Override
     public void push(T value) {
         stack.add(value);
     }
 
+    /**
+     * Removes and returns the element from the top of the stack.
+     *
+     * @return the element removed from the top of the stack
+     * @throws EmptyStackException if the stack is empty
+     */
     @Override
     public T pop() {
         if (isEmpty()) {
@@ -29,6 +47,12 @@ public T pop() {
         return stack.removeLast();
     }
 
+    /**
+     * Returns the element at the top of the stack without removing it.
+     *
+     * @return the top element of the stack
+     * @throws EmptyStackException if the stack is empty
+     */
     @Override
     public T peek() {
         if (isEmpty()) {
@@ -37,16 +61,29 @@ public T peek() {
         return stack.getLast();
     }
 
+    /**
+     * Checks if the stack is empty.
+     *
+     * @return {@code true} if the stack is empty, {@code false} otherwise
+     */
     @Override
     public boolean isEmpty() {
         return stack.isEmpty();
     }
 
+    /**
+     * Empties the stack, removing all elements.
+     */
     @Override
     public void makeEmpty() {
         stack.clear();
     }
 
+    /**
+     * Returns the number of elements in the stack.
+     *
+     * @return the current size of the stack
+     */
     @Override
     public int size() {
         return stack.size();
diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java
index f4c261904bb4..c8811bb3ccc2 100644
--- a/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java
@@ -30,18 +30,18 @@ void testPeek() {
         stack.push(10);
         stack.push(20);
 
-        Assertions.assertEquals(20, stack.peek());
-        stack.pop(); // Remove 20
-        Assertions.assertEquals(10, stack.peek());
+        Assertions.assertEquals(20, stack.peek()); // Peek should return the top element
+        stack.pop(); // Remove top element
+        Assertions.assertEquals(10, stack.peek()); // Peek should now return the new top element
     }
 
     @Test
     void testIsEmpty() {
-        Assertions.assertTrue(stack.isEmpty());
+        Assertions.assertTrue(stack.isEmpty()); // Stack should initially be empty
         stack.push(1);
-        Assertions.assertFalse(stack.isEmpty());
+        Assertions.assertFalse(stack.isEmpty()); // After pushing, stack should not be empty
         stack.pop();
-        Assertions.assertTrue(stack.isEmpty());
+        Assertions.assertTrue(stack.isEmpty()); // After popping, stack should be empty again
     }
 
     @Test
@@ -50,27 +50,58 @@ void testMakeEmpty() {
         stack.push(2);
         stack.push(3);
         stack.makeEmpty();
-        Assertions.assertTrue(stack.isEmpty());
-        Assertions.assertEquals(0, stack.size());
+        Assertions.assertTrue(stack.isEmpty()); // Stack should be empty after makeEmpty is called
+        Assertions.assertEquals(0, stack.size()); // Size should be 0 after makeEmpty
     }
 
     @Test
     void testSize() {
-        Assertions.assertEquals(0, stack.size());
+        Assertions.assertEquals(0, stack.size()); // Initial size should be 0
         stack.push(1);
         stack.push(2);
-        Assertions.assertEquals(2, stack.size());
+        Assertions.assertEquals(2, stack.size()); // Size should reflect number of elements added
         stack.pop();
-        Assertions.assertEquals(1, stack.size());
+        Assertions.assertEquals(1, stack.size()); // Size should decrease with elements removed
     }
 
     @Test
     void testPopEmptyStackThrowsException() {
-        Assertions.assertThrows(EmptyStackException.class, stack::pop);
+        Assertions.assertThrows(EmptyStackException.class, stack::pop); // Popping from an empty stack should throw an exception
     }
 
     @Test
     void testPeekEmptyStackThrowsException() {
-        Assertions.assertThrows(EmptyStackException.class, stack::peek);
+        Assertions.assertThrows(EmptyStackException.class, stack::peek); // Peeking into an empty stack should throw an exception
+    }
+
+    @Test
+    void testMixedOperations() {
+        // Testing a mix of push, pop, peek, and size operations in sequence
+        stack.push(5);
+        stack.push(10);
+        stack.push(15);
+
+        Assertions.assertEquals(3, stack.size()); // Size should reflect number of elements
+        Assertions.assertEquals(15, stack.peek()); // Peek should show last element added
+
+        stack.pop(); // Remove top element
+        Assertions.assertEquals(10, stack.peek()); // New top should be 10
+        Assertions.assertEquals(2, stack.size()); // Size should reflect removal
+
+        stack.push(20); // Add a new element
+        Assertions.assertEquals(20, stack.peek()); // Top should be the last added element
+    }
+
+    @Test
+    void testMultipleMakeEmptyCalls() {
+        // Ensures calling makeEmpty multiple times does not throw errors or misbehave
+        stack.push(1);
+        stack.push(2);
+        stack.makeEmpty();
+        Assertions.assertTrue(stack.isEmpty());
+
+        stack.makeEmpty();
+        Assertions.assertTrue(stack.isEmpty());
+        Assertions.assertEquals(0, stack.size());
     }
 }

From 59a8e1d41815f4681c260ca933c62293ea541cba Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 11:59:30 +0530
Subject: [PATCH 0629/1338] Enhance docs, add tests in `SortedLinkedList`
 (#6014)

---
 .../lists/SortedLinkedList.java               |  64 +++++++----
 .../lists/SortedLinkedListTest.java           | 102 ++++++++++++++----
 2 files changed, 124 insertions(+), 42 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java
index 4cf782679b7c..e515c9e4adc4 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java
@@ -4,24 +4,42 @@
 import java.util.List;
 
 /**
- * A SortedLinkedList is a data structure that maintains a sorted list of elements.
- * Elements are ordered based on their natural ordering or by a Comparator provided at the time of creation.
- * This implementation uses a singly linked list to store the elements.
- * Further details can be found on this link
+ * The SortedLinkedList class represents a singly linked list that maintains its elements in sorted order.
+ * Elements are ordered based on their natural ordering, with smaller elements at the head and larger elements toward the tail.
+ * The class provides methods for inserting, deleting, and searching elements, as well as checking if the list is empty.
+ * <p>
+ * This implementation utilizes a singly linked list to maintain a dynamically sorted list.
+ * </p>
+ * <p>
+ * Further information can be found here:
  * https://runestone.academy/ns/books/published/cppds/LinearLinked/ImplementinganOrderedList.html
+ * </p>
+ *
+ * <b>Usage Example:</b>
+ * <pre>
+ *     SortedLinkedList list = new SortedLinkedList();
+ *     list.insert(10);
+ *     list.insert(5);
+ *     list.insert(20);
+ *     System.out.println(list); // Outputs: [5, 10, 20]
+ * </pre>
  */
 public class SortedLinkedList {
     private Node head;
     private Node tail;
 
+    /**
+     * Initializes an empty sorted linked list.
+     */
     public SortedLinkedList() {
         this.head = null;
         this.tail = null;
     }
 
     /**
-     * Inserts a new element into the sorted linked list.
-     * @param value the value to be inserted
+     * Inserts a new integer into the list, maintaining sorted order.
+     *
+     * @param value the integer to insert
      */
     public void insert(int value) {
         Node newNode = new Node(value);
@@ -48,16 +66,10 @@ public void insert(int value) {
     }
 
     /**
-     * Displays the elements of the sorted linked list.
-     */
-    public void display() {
-        System.out.println(this.toString());
-    }
-
-    /**
-     * Deletes the first occurrence of the specified element in the sorted linked list.
-     * @param value the value to be deleted
-     * @return true if the element is found and deleted, false otherwise
+     * Deletes the first occurrence of a specified integer in the list.
+     *
+     * @param value the integer to delete
+     * @return {@code true} if the element was found and deleted; {@code false} otherwise
      */
     public boolean delete(int value) {
         if (this.head == null) {
@@ -87,9 +99,10 @@ public boolean delete(int value) {
     }
 
     /**
-     * Searches for the specified element in the sorted linked list.
-     * @param value the value to be searched
-     * @return true if the element is found, false otherwise
+     * Searches for a specified integer in the list.
+     *
+     * @param value the integer to search for
+     * @return {@code true} if the value is present in the list; {@code false} otherwise
      */
     public boolean search(int value) {
         Node temp = this.head;
@@ -103,14 +116,17 @@ public boolean search(int value) {
     }
 
     /**
-     * Checks if the sorted linked list is empty.
-     * @return true if the list is empty, false otherwise
+     * Checks if the list is empty.
+     *
+     * @return {@code true} if the list is empty; {@code false} otherwise
      */
     public boolean isEmpty() {
         return head == null;
     }
+
     /**
-     * Returns a string representation of the sorted linked list.
+     * Returns a string representation of the sorted linked list in the format [element1, element2, ...].
+     *
      * @return a string representation of the sorted linked list
      */
     @Override
@@ -123,12 +139,14 @@ public String toString() {
                 temp = temp.next;
             }
             return "[" + String.join(", ", elements) + "]";
-
         } else {
             return "[]";
         }
     }
 
+    /**
+     * Node represents an element in the sorted linked list.
+     */
     public final class Node {
         public final int value;
         public Node next;
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java
index 4877e6db4ec4..82e0853da374 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java
@@ -4,13 +4,26 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 public class SortedLinkedListTest {
 
+    private SortedLinkedList list;
+
+    @BeforeEach
+    public void setUp() {
+        list = new SortedLinkedList();
+    }
+
+    @Test
+    public void testInsertIntoEmptyList() {
+        list.insert(5);
+        assertEquals("[5]", list.toString());
+    }
+
     @Test
-    public void testInsert() {
-        SortedLinkedList list = new SortedLinkedList();
+    public void testInsertInSortedOrder() {
         list.insert(5);
         list.insert(3);
         list.insert(7);
@@ -18,48 +31,99 @@ public void testInsert() {
     }
 
     @Test
-    public void testDelete() {
-        SortedLinkedList list = new SortedLinkedList();
+    public void testInsertDuplicateValues() {
         list.insert(5);
+        list.insert(5);
+        list.insert(5);
+        assertEquals("[5, 5, 5]", list.toString());
+    }
+
+    @Test
+    public void testDeleteHeadElement() {
+        list.insert(1);
+        list.insert(2);
         list.insert(3);
-        list.insert(7);
-        assertTrue(list.delete(5));
-        assertEquals("[3, 7]", list.toString());
-        assertFalse(list.delete(10));
+        assertTrue(list.delete(1));
+        assertEquals("[2, 3]", list.toString());
     }
 
     @Test
-    public void testSearch() {
-        SortedLinkedList list = new SortedLinkedList();
-        list.insert(5);
+    public void testDeleteTailElement() {
+        list.insert(1);
+        list.insert(2);
         list.insert(3);
-        list.insert(7);
-        assertTrue(list.search(5));
-        assertFalse(list.search(10));
+        assertTrue(list.delete(3));
+        assertEquals("[1, 2]", list.toString());
+    }
+
+    @Test
+    public void testDeleteMiddleElement() {
+        list.insert(1);
+        list.insert(2);
+        list.insert(3);
+        assertTrue(list.delete(2));
+        assertEquals("[1, 3]", list.toString());
+    }
+
+    @Test
+    public void testDeleteNonexistentElement() {
+        list.insert(1);
+        list.insert(2);
+        assertFalse(list.delete(3));
     }
+
     @Test
-    public void testEmptyList() {
-        SortedLinkedList list = new SortedLinkedList();
+    public void testDeleteFromSingleElementList() {
+        list.insert(5);
+        assertTrue(list.delete(5));
         assertEquals("[]", list.toString());
+    }
+
+    @Test
+    public void testDeleteFromEmptyList() {
         assertFalse(list.delete(5));
+    }
+
+    @Test
+    public void testSearchInEmptyList() {
         assertFalse(list.search(5));
     }
+
+    @Test
+    public void testSearchForExistingElement() {
+        list.insert(3);
+        list.insert(1);
+        list.insert(5);
+        assertTrue(list.search(3));
+    }
+
+    @Test
+    public void testSearchForNonexistentElement() {
+        list.insert(3);
+        list.insert(1);
+        list.insert(5);
+        assertFalse(list.search(10));
+    }
+
     @Test
     public void testIsEmptyOnEmptyList() {
-        SortedLinkedList list = new SortedLinkedList();
         assertTrue(list.isEmpty());
     }
 
     @Test
     public void testIsEmptyOnNonEmptyList() {
-        SortedLinkedList list = new SortedLinkedList();
+        list.insert(10);
+        assertFalse(list.isEmpty());
+    }
+
+    @Test
+    public void testIsEmptyAfterInsertion() {
         list.insert(10);
         assertFalse(list.isEmpty());
     }
 
     @Test
     public void testIsEmptyAfterDeletion() {
-        SortedLinkedList list = new SortedLinkedList();
         list.insert(10);
         list.delete(10);
         assertTrue(list.isEmpty());

From 92a04f8f8d00a1472a2670c953e0ed3d15926c2e Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 12:10:39 +0530
Subject: [PATCH 0630/1338] Add `SlackTimeScheduling` algorithm (#5814)

---
 DIRECTORY.md                                  |  2 +
 .../scheduling/SlackTimeScheduling.java       | 64 +++++++++++++++++++
 .../scheduling/SlackTimeSchedulingTest.java   | 48 ++++++++++++++
 3 files changed, 114 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/SlackTimeScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/SlackTimeSchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 78ff31bf910f..804320a28db5 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -539,6 +539,7 @@
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
             * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
+            * [SlackTimeScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SlackTimeScheduling.java)
             * [SRTFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java)
           * searches
             * [BinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BinarySearch.java)
@@ -1134,6 +1135,7 @@
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
             * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)
+            * [SlackTimeSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SlackTimeSchedulingTest.java)
             * [SRTFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java)
           * searches
             * [BinarySearch2dArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/SlackTimeScheduling.java b/src/main/java/com/thealgorithms/scheduling/SlackTimeScheduling.java
new file mode 100644
index 000000000000..bbfd36f0f660
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/SlackTimeScheduling.java
@@ -0,0 +1,64 @@
+package com.thealgorithms.scheduling;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * SlackTimeScheduling is an algorithm that prioritizes tasks based on their
+ * slack time, which is defined as the difference between the task's deadline
+ * and the time required to execute it. Tasks with less slack time are prioritized.
+ *
+ * Use Case: Real-time systems with hard deadlines, such as robotics or embedded systems.
+ *
+ * @author Hardvan
+ */
+public class SlackTimeScheduling {
+
+    static class Task {
+        String name;
+        int executionTime;
+        int deadline;
+
+        Task(String name, int executionTime, int deadline) {
+            this.name = name;
+            this.executionTime = executionTime;
+            this.deadline = deadline;
+        }
+
+        int getSlackTime() {
+            return deadline - executionTime;
+        }
+    }
+
+    private final List<Task> tasks;
+
+    public SlackTimeScheduling() {
+        tasks = new ArrayList<>();
+    }
+
+    /**
+     * Adds a task to the scheduler.
+     *
+     * @param name          the name of the task
+     * @param executionTime the time required to execute the task
+     * @param deadline      the deadline by which the task must be completed
+     */
+    public void addTask(String name, int executionTime, int deadline) {
+        tasks.add(new Task(name, executionTime, deadline));
+    }
+
+    /**
+     * Schedules the tasks based on their slack time.
+     *
+     * @return the order in which the tasks should be executed
+     */
+    public List<String> scheduleTasks() {
+        tasks.sort(Comparator.comparingInt(Task::getSlackTime));
+        List<String> scheduledOrder = new ArrayList<>();
+        for (Task task : tasks) {
+            scheduledOrder.add(task.name);
+        }
+        return scheduledOrder;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/SlackTimeSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/SlackTimeSchedulingTest.java
new file mode 100644
index 000000000000..555a0941e7f5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/SlackTimeSchedulingTest.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class SlackTimeSchedulingTest {
+
+    private SlackTimeScheduling scheduler;
+
+    @BeforeEach
+    public void setup() {
+        scheduler = new SlackTimeScheduling();
+    }
+
+    @Test
+    public void testAddAndScheduleSingleTask() {
+        scheduler.addTask("Task1", 2, 5);
+        List<String> expected = List.of("Task1");
+        assertEquals(expected, scheduler.scheduleTasks());
+    }
+
+    @Test
+    public void testScheduleMultipleTasks() {
+        scheduler.addTask("Task1", 2, 5);
+        scheduler.addTask("Task2", 1, 4);
+        scheduler.addTask("Task3", 3, 7);
+        List<String> expected = List.of("Task1", "Task2", "Task3");
+        assertEquals(expected, scheduler.scheduleTasks());
+    }
+
+    @Test
+    public void testScheduleTasksWithSameSlackTime() {
+        scheduler.addTask("Task1", 2, 5);
+        scheduler.addTask("Task2", 3, 6);
+        scheduler.addTask("Task3", 1, 4);
+        List<String> expected = List.of("Task1", "Task2", "Task3");
+        assertEquals(expected, scheduler.scheduleTasks());
+    }
+
+    @Test
+    public void testEmptyScheduler() {
+        List<String> expected = List.of();
+        assertEquals(expected, scheduler.scheduleTasks());
+    }
+}

From 32cb98db011ebd3c4ad0756fbe5dec2dba5b3d3a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 12:23:36 +0530
Subject: [PATCH 0631/1338] Add `MultiAgentScheduling` algorithm (#5816)

---
 DIRECTORY.md                                  |  2 +
 .../scheduling/MultiAgentScheduling.java      | 72 +++++++++++++++++++
 .../scheduling/MultiAgentSchedulingTest.java  | 52 ++++++++++++++
 3 files changed, 126 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/MultiAgentScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/MultiAgentSchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 804320a28db5..a1bbbf9afa94 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -535,6 +535,7 @@
             * [JobSchedulingWithDeadline](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java)
             * [LotteryScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/LotteryScheduling.java)
             * [MLFQScheduler](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java)
+            * [MultiAgentScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MultiAgentScheduling.java)
             * [NonPreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
@@ -1131,6 +1132,7 @@
             * [JobSchedulingWithDeadlineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java)
             * [LotterySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/LotterySchedulingTest.java)
             * [MLFQSchedulerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java)
+            * [MultiAgentSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MultiAgentSchedulingTest.java)
             * [NonPreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/MultiAgentScheduling.java b/src/main/java/com/thealgorithms/scheduling/MultiAgentScheduling.java
new file mode 100644
index 000000000000..113b1691dec1
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/MultiAgentScheduling.java
@@ -0,0 +1,72 @@
+package com.thealgorithms.scheduling;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * MultiAgentScheduling assigns tasks to different autonomous agents
+ * who independently decide the execution order of their assigned tasks.
+ * The focus is on collaboration between agents to optimize the overall schedule.
+ *
+ * Use Case: Distributed scheduling in decentralized systems like IoT networks.
+ *
+ * @author Hardvan
+ */
+public class MultiAgentScheduling {
+
+    static class Agent {
+        String name;
+        List<String> tasks;
+
+        Agent(String name) {
+            this.name = name;
+            this.tasks = new ArrayList<>();
+        }
+
+        void addTask(String task) {
+            tasks.add(task);
+        }
+
+        List<String> getTasks() {
+            return tasks;
+        }
+    }
+
+    private final Map<String, Agent> agents;
+
+    public MultiAgentScheduling() {
+        agents = new HashMap<>();
+    }
+
+    public void addAgent(String agentName) {
+        agents.putIfAbsent(agentName, new Agent(agentName));
+    }
+
+    /**
+     * Assign a task to a specific agent.
+     *
+     * @param agentName the name of the agent
+     * @param task      the task to be assigned
+     */
+    public void assignTask(String agentName, String task) {
+        Agent agent = agents.get(agentName);
+        if (agent != null) {
+            agent.addTask(task);
+        }
+    }
+
+    /**
+     * Get the scheduled tasks for each agent.
+     *
+     * @return a map of agent names to their scheduled tasks
+     */
+    public Map<String, List<String>> getScheduledTasks() {
+        Map<String, List<String>> schedule = new HashMap<>();
+        for (Agent agent : agents.values()) {
+            schedule.put(agent.name, agent.getTasks());
+        }
+        return schedule;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/MultiAgentSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/MultiAgentSchedulingTest.java
new file mode 100644
index 000000000000..16067fa8c22a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/MultiAgentSchedulingTest.java
@@ -0,0 +1,52 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.Map;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class MultiAgentSchedulingTest {
+
+    private MultiAgentScheduling scheduler;
+
+    @BeforeEach
+    public void setup() {
+        scheduler = new MultiAgentScheduling();
+    }
+
+    @Test
+    public void testAddAgentAndAssignTask() {
+        scheduler.addAgent("Agent1");
+        scheduler.assignTask("Agent1", "Task1");
+        Map<String, List<String>> expected = Map.of("Agent1", List.of("Task1"));
+        assertEquals(expected, scheduler.getScheduledTasks());
+    }
+
+    @Test
+    public void testMultipleAgentsWithTasks() {
+        scheduler.addAgent("Agent1");
+        scheduler.addAgent("Agent2");
+        scheduler.assignTask("Agent1", "Task1");
+        scheduler.assignTask("Agent2", "Task2");
+        Map<String, List<String>> expected = Map.of("Agent1", List.of("Task1"), "Agent2", List.of("Task2"));
+        assertEquals(expected, scheduler.getScheduledTasks());
+    }
+
+    @Test
+    public void testAgentWithMultipleTasks() {
+        scheduler.addAgent("Agent1");
+        scheduler.assignTask("Agent1", "Task1");
+        scheduler.assignTask("Agent1", "Task2");
+        Map<String, List<String>> expected = Map.of("Agent1", List.of("Task1", "Task2"));
+        assertEquals(expected, scheduler.getScheduledTasks());
+    }
+
+    @Test
+    public void testEmptyAgentSchedule() {
+        scheduler.addAgent("Agent1");
+        Map<String, List<String>> expected = Map.of("Agent1", List.of());
+        assertEquals(expected, scheduler.getScheduledTasks());
+    }
+}

From 7a539bc17f6518944277846bb82ad9f853684fed Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 12:31:07 +0530
Subject: [PATCH 0632/1338] Add `SelfAdjustingScheduling` algorithm (#5811)

---
 DIRECTORY.md                                  |  2 +
 .../scheduling/SelfAdjustingScheduling.java   | 63 +++++++++++++++++++
 .../SelfAdjustingSchedulingTest.java          | 57 +++++++++++++++++
 3 files changed, 122 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a1bbbf9afa94..f6e7ebe44e67 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -539,6 +539,7 @@
             * [NonPreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
+            * [SelfAdjustingScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java)
             * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
             * [SlackTimeScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SlackTimeScheduling.java)
             * [SRTFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java)
@@ -1136,6 +1137,7 @@
             * [NonPreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
+            * [SelfAdjustingSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java)
             * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)
             * [SlackTimeSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SlackTimeSchedulingTest.java)
             * [SRTFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java b/src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java
new file mode 100644
index 000000000000..15159a07d2d4
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java
@@ -0,0 +1,63 @@
+package com.thealgorithms.scheduling;
+
+import java.util.PriorityQueue;
+
+/**
+ * SelfAdjustingScheduling is an algorithm where tasks dynamically adjust
+ * their priority based on real-time feedback, such as wait time and CPU usage.
+ * Tasks that wait longer will automatically increase their priority,
+ * allowing for better responsiveness and fairness in task handling.
+ *
+ * Use Case: Real-time systems that require dynamic prioritization
+ * of tasks to maintain system responsiveness and fairness.
+ *
+ * @author Hardvan
+ */
+public final class SelfAdjustingScheduling {
+
+    private static class Task implements Comparable<Task> {
+        String name;
+        int waitTime;
+        int priority;
+
+        Task(String name, int priority) {
+            this.name = name;
+            this.waitTime = 0;
+            this.priority = priority;
+        }
+
+        void incrementWaitTime() {
+            waitTime++;
+            priority = priority + waitTime;
+        }
+
+        @Override
+        public int compareTo(Task other) {
+            return Integer.compare(this.priority, other.priority);
+        }
+    }
+
+    private final PriorityQueue<Task> taskQueue;
+
+    public SelfAdjustingScheduling() {
+        taskQueue = new PriorityQueue<>();
+    }
+
+    public void addTask(String name, int priority) {
+        taskQueue.offer(new Task(name, priority));
+    }
+
+    public String scheduleNext() {
+        if (taskQueue.isEmpty()) {
+            return null;
+        }
+        Task nextTask = taskQueue.poll();
+        nextTask.incrementWaitTime();
+        taskQueue.offer(nextTask);
+        return nextTask.name;
+    }
+
+    public boolean isEmpty() {
+        return taskQueue.isEmpty();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java
new file mode 100644
index 000000000000..8675a1ec397d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java
@@ -0,0 +1,57 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class SelfAdjustingSchedulingTest {
+
+    private SelfAdjustingScheduling scheduler;
+
+    @BeforeEach
+    public void setup() {
+        scheduler = new SelfAdjustingScheduling();
+    }
+
+    @Test
+    public void testAddAndScheduleSingleTask() {
+        scheduler.addTask("Task1", 5);
+        assertEquals("Task1", scheduler.scheduleNext());
+    }
+
+    @Test
+    public void testAddMultipleTasks() {
+        scheduler.addTask("Task1", 5);
+        scheduler.addTask("Task2", 1);
+        scheduler.addTask("Task3", 3);
+        assertEquals("Task2", scheduler.scheduleNext());
+        assertEquals("Task2", scheduler.scheduleNext());
+        assertEquals("Task3", scheduler.scheduleNext());
+    }
+
+    @Test
+    public void testPriorityAdjustment() {
+        scheduler.addTask("Task1", 1);
+        scheduler.addTask("Task2", 1);
+        scheduler.scheduleNext();
+        scheduler.scheduleNext();
+        scheduler.scheduleNext();
+        assertEquals("Task2", scheduler.scheduleNext());
+    }
+
+    @Test
+    public void testEmptyScheduler() {
+        assertNull(scheduler.scheduleNext());
+    }
+
+    @Test
+    public void testTaskReschedulingAfterWait() {
+        scheduler.addTask("Task1", 1);
+        scheduler.addTask("Task2", 2);
+        scheduler.scheduleNext();
+        scheduler.scheduleNext();
+        assertEquals("Task1", scheduler.scheduleNext());
+    }
+}

From ecf4c3768facfd00582fe0d229977b47cbb88779 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 12:34:38 +0530
Subject: [PATCH 0633/1338] Add `ProportionalFairScheduling` algorithm (#5812)

---
 DIRECTORY.md                                  |  2 +
 .../ProportionalFairScheduling.java           | 54 +++++++++++++++++++
 .../ProportionalFairSchedulingTest.java       | 53 ++++++++++++++++++
 3 files changed, 109 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index f6e7ebe44e67..34ded2cebf9a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -538,6 +538,7 @@
             * [MultiAgentScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MultiAgentScheduling.java)
             * [NonPreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
+            * [ProportionalFairScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
             * [SelfAdjustingScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java)
             * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
@@ -1136,6 +1137,7 @@
             * [MultiAgentSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MultiAgentSchedulingTest.java)
             * [NonPreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
+            * [ProportionalFairSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
             * [SelfAdjustingSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java)
             * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java b/src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java
new file mode 100644
index 000000000000..fd78dc571819
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.scheduling;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * ProportionalFairScheduling allocates resources to processes based on their
+ * proportional weight or importance. It aims to balance fairness with
+ * priority, ensuring that higher-weight processes receive a larger share of resources.
+ *
+ * Use Case: Network bandwidth allocation in cellular networks (4G/5G),
+ * where devices receive a proportional share of bandwidth.
+ *
+ * @author Hardvan
+ */
+public final class ProportionalFairScheduling {
+
+    static class Process {
+        String name;
+        int weight;
+        int allocatedResources;
+
+        Process(String name, int weight) {
+            this.name = name;
+            this.weight = weight;
+            this.allocatedResources = 0;
+        }
+    }
+
+    private final List<Process> processes;
+
+    public ProportionalFairScheduling() {
+        processes = new ArrayList<>();
+    }
+
+    public void addProcess(String name, int weight) {
+        processes.add(new Process(name, weight));
+    }
+
+    public void allocateResources(int totalResources) {
+        int totalWeight = processes.stream().mapToInt(p -> p.weight).sum();
+        for (Process process : processes) {
+            process.allocatedResources = (int) ((double) process.weight / totalWeight * totalResources);
+        }
+    }
+
+    public List<String> getAllocatedResources() {
+        List<String> allocation = new ArrayList<>();
+        for (Process process : processes) {
+            allocation.add(process.name + ": " + process.allocatedResources);
+        }
+        return allocation;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java
new file mode 100644
index 000000000000..0d379ee90b0e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class ProportionalFairSchedulingTest {
+
+    private ProportionalFairScheduling scheduler;
+
+    @BeforeEach
+    public void setup() {
+        scheduler = new ProportionalFairScheduling();
+    }
+
+    @Test
+    public void testAllocateResourcesSingleProcess() {
+        scheduler.addProcess("Process1", 5);
+        scheduler.allocateResources(100);
+        List<String> expected = List.of("Process1: 100");
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+
+    @Test
+    public void testAllocateResourcesMultipleProcesses() {
+        scheduler.addProcess("Process1", 2);
+        scheduler.addProcess("Process2", 3);
+        scheduler.addProcess("Process3", 5);
+        scheduler.allocateResources(100);
+        List<String> expected = List.of("Process1: 20", "Process2: 30", "Process3: 50");
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+
+    @Test
+    public void testAllocateResourcesZeroWeightProcess() {
+        scheduler.addProcess("Process1", 0);
+        scheduler.addProcess("Process2", 5);
+        scheduler.allocateResources(100);
+        List<String> expected = List.of("Process1: 0", "Process2: 100");
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+
+    @Test
+    public void testAllocateResourcesEqualWeights() {
+        scheduler.addProcess("Process1", 1);
+        scheduler.addProcess("Process2", 1);
+        scheduler.allocateResources(100);
+        List<String> expected = List.of("Process1: 50", "Process2: 50");
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+}

From acbce00177f956ccec434395591ab9d2d13dd026 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 12:41:51 +0530
Subject: [PATCH 0634/1338] Add `FairShareScheduling` algorithm (#5815)

---
 DIRECTORY.md                                  |  2 +
 .../scheduling/FairShareScheduling.java       | 65 +++++++++++++++++++
 .../scheduling/FairShareSchedulingTest.java   | 60 +++++++++++++++++
 3 files changed, 127 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/FairShareScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/FairShareSchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 34ded2cebf9a..774a18601ba8 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -530,6 +530,7 @@
               * [ScanScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/ScanScheduling.java)
               * [SSFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java)
             * [EDFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/EDFScheduling.java)
+            * [FairShareScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FairShareScheduling.java)
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
             * [HighestResponseRatioNextScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
             * [JobSchedulingWithDeadline](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java)
@@ -1129,6 +1130,7 @@
               * [ScanSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java)
               * [SSFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/SSFSchedulingTest.java)
             * [EDFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java)
+            * [FairShareSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FairShareSchedulingTest.java)
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
             * [HighestResponseRatioNextSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
             * [JobSchedulingWithDeadlineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/FairShareScheduling.java b/src/main/java/com/thealgorithms/scheduling/FairShareScheduling.java
new file mode 100644
index 000000000000..776fc59c0c4d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/FairShareScheduling.java
@@ -0,0 +1,65 @@
+package com.thealgorithms.scheduling;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * FairShareScheduling allocates CPU resources equally among users or groups
+ * instead of individual tasks. Each group gets a proportional share,
+ * preventing resource hogging by a single user's processes.
+ *
+ * Use Case: Multi-user systems where users submit multiple tasks simultaneously,
+ * such as cloud environments.
+ *
+ * @author Hardvan
+ */
+public final class FairShareScheduling {
+
+    static class User {
+        String name;
+        int allocatedResources;
+        int totalWeight;
+
+        User(String name) {
+            this.name = name;
+            this.allocatedResources = 0;
+            this.totalWeight = 0;
+        }
+
+        void addWeight(int weight) {
+            this.totalWeight += weight;
+        }
+    }
+
+    private final Map<String, User> users; // username -> User
+
+    public FairShareScheduling() {
+        users = new HashMap<>();
+    }
+
+    public void addUser(String userName) {
+        users.putIfAbsent(userName, new User(userName));
+    }
+
+    public void addTask(String userName, int weight) {
+        User user = users.get(userName);
+        if (user != null) {
+            user.addWeight(weight);
+        }
+    }
+
+    public void allocateResources(int totalResources) {
+        int totalWeights = users.values().stream().mapToInt(user -> user.totalWeight).sum();
+        for (User user : users.values()) {
+            user.allocatedResources = (int) ((double) user.totalWeight / totalWeights * totalResources);
+        }
+    }
+
+    public Map<String, Integer> getAllocatedResources() {
+        Map<String, Integer> allocation = new HashMap<>();
+        for (User user : users.values()) {
+            allocation.put(user.name, user.allocatedResources);
+        }
+        return allocation;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/FairShareSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/FairShareSchedulingTest.java
new file mode 100644
index 000000000000..7aa6e061c497
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/FairShareSchedulingTest.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Map;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class FairShareSchedulingTest {
+
+    private FairShareScheduling scheduler;
+
+    @BeforeEach
+    public void setup() {
+        scheduler = new FairShareScheduling();
+    }
+
+    @Test
+    public void testAllocateResourcesSingleUser() {
+        scheduler.addUser("User1");
+        scheduler.addTask("User1", 5);
+        scheduler.allocateResources(100);
+        Map<String, Integer> expected = Map.of("User1", 100);
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+
+    @Test
+    public void testAllocateResourcesMultipleUsers() {
+        scheduler.addUser("User1");
+        scheduler.addUser("User2");
+        scheduler.addUser("User3");
+        scheduler.addTask("User1", 2);
+        scheduler.addTask("User2", 3);
+        scheduler.addTask("User3", 5);
+        scheduler.allocateResources(100);
+        Map<String, Integer> expected = Map.of("User1", 20, "User2", 30, "User3", 50);
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+
+    @Test
+    public void testAllocateResourcesZeroWeightUser() {
+        scheduler.addUser("User1");
+        scheduler.addUser("User2");
+        scheduler.addTask("User2", 5);
+        scheduler.allocateResources(100);
+        Map<String, Integer> expected = Map.of("User1", 0, "User2", 100);
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+
+    @Test
+    public void testAllocateResourcesEqualWeights() {
+        scheduler.addUser("User1");
+        scheduler.addUser("User2");
+        scheduler.addTask("User1", 1);
+        scheduler.addTask("User2", 1);
+        scheduler.allocateResources(100);
+        Map<String, Integer> expected = Map.of("User1", 50, "User2", 50);
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+}

From 1d194499316927c66c489786727b0aedb4203a23 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 12:51:47 +0530
Subject: [PATCH 0635/1338] Add `AgingScheduling` algorithm (#5813)

---
 DIRECTORY.md                                  |  2 +
 .../scheduling/AgingScheduling.java           | 62 +++++++++++++++++++
 .../scheduling/AgingSchedulingTest.java       | 54 ++++++++++++++++
 3 files changed, 118 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/AgingScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/AgingSchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 774a18601ba8..476308a35617 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -523,6 +523,7 @@
           * Recursion
             * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java)
           * scheduling
+            * [AgingScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/AgingScheduling.java)
             * diskscheduling
               * [CircularLookScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularLookScheduling.java)
               * [CircularScanScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularScanScheduling.java)
@@ -1123,6 +1124,7 @@
           * Recursion
             * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java)
           * scheduling
+            * [AgingSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/AgingSchedulingTest.java)
             * diskscheduling
               * [CircularLookSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java)
               * [CircularScanSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/AgingScheduling.java b/src/main/java/com/thealgorithms/scheduling/AgingScheduling.java
new file mode 100644
index 000000000000..1e5512be9edd
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/AgingScheduling.java
@@ -0,0 +1,62 @@
+package com.thealgorithms.scheduling;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+/**
+ * AgingScheduling is an algorithm designed to prevent starvation
+ * by gradually increasing the priority of waiting tasks.
+ * The longer a process waits, the higher its priority becomes.
+ *
+ * Use Case: Useful in systems with mixed workloads to avoid
+ * lower-priority tasks being starved by higher-priority tasks.
+ *
+ * @author Hardvan
+ */
+public final class AgingScheduling {
+
+    static class Task {
+        String name;
+        int waitTime;
+        int priority;
+
+        Task(String name, int priority) {
+            this.name = name;
+            this.priority = priority;
+            this.waitTime = 0;
+        }
+    }
+
+    private final Queue<Task> taskQueue;
+
+    public AgingScheduling() {
+        taskQueue = new LinkedList<>();
+    }
+
+    /**
+     * Adds a task to the scheduler with a given priority.
+     *
+     * @param name name of the task
+     * @param priority priority of the task
+     */
+    public void addTask(String name, int priority) {
+        taskQueue.offer(new Task(name, priority));
+    }
+
+    /**
+     * Schedules the next task based on the priority and wait time.
+     * The priority of a task increases with the time it spends waiting.
+     *
+     * @return name of the next task to be executed
+     */
+    public String scheduleNext() {
+        if (taskQueue.isEmpty()) {
+            return null;
+        }
+        Task nextTask = taskQueue.poll();
+        nextTask.waitTime++;
+        nextTask.priority += nextTask.waitTime;
+        taskQueue.offer(nextTask);
+        return nextTask.name;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/AgingSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/AgingSchedulingTest.java
new file mode 100644
index 000000000000..cab78e4d1c58
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/AgingSchedulingTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class AgingSchedulingTest {
+
+    private AgingScheduling scheduler;
+
+    @BeforeEach
+    public void setup() {
+        scheduler = new AgingScheduling();
+    }
+
+    @Test
+    public void testAddAndScheduleSingleTask() {
+        scheduler.addTask("Task1", 5);
+        assertEquals("Task1", scheduler.scheduleNext());
+    }
+
+    @Test
+    public void testAddMultipleTasks() {
+        scheduler.addTask("Task1", 1);
+        scheduler.addTask("Task2", 1);
+        assertEquals("Task1", scheduler.scheduleNext());
+        assertEquals("Task2", scheduler.scheduleNext());
+    }
+
+    @Test
+    public void testPriorityAdjustmentWithWait() {
+        scheduler.addTask("Task1", 1);
+        scheduler.addTask("Task2", 1);
+        scheduler.scheduleNext();
+        scheduler.scheduleNext();
+        assertEquals("Task1", scheduler.scheduleNext());
+    }
+
+    @Test
+    public void testEmptyScheduler() {
+        assertNull(scheduler.scheduleNext());
+    }
+
+    @Test
+    public void testMultipleRounds() {
+        scheduler.addTask("Task1", 1);
+        scheduler.addTask("Task2", 2);
+        scheduler.scheduleNext();
+        scheduler.scheduleNext();
+        assertEquals("Task1", scheduler.scheduleNext());
+    }
+}

From f3c2be2c396957b6de4f81d76cbacd4e1fc2beab Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 12:55:20 +0530
Subject: [PATCH 0636/1338] Add `GangScheduling` algorithm (#5819)

---
 DIRECTORY.md                                  |  2 +
 .../scheduling/GangScheduling.java            | 61 +++++++++++++++++++
 .../scheduling/GangSchedulingTest.java        | 52 ++++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/GangScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/GangSchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 476308a35617..ad893d45f5dc 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -533,6 +533,7 @@
             * [EDFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/EDFScheduling.java)
             * [FairShareScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FairShareScheduling.java)
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
+            * [GangScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/GangScheduling.java)
             * [HighestResponseRatioNextScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
             * [JobSchedulingWithDeadline](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java)
             * [LotteryScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/LotteryScheduling.java)
@@ -1134,6 +1135,7 @@
             * [EDFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java)
             * [FairShareSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FairShareSchedulingTest.java)
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
+            * [GangSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/GangSchedulingTest.java)
             * [HighestResponseRatioNextSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
             * [JobSchedulingWithDeadlineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java)
             * [LotterySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/LotterySchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/GangScheduling.java b/src/main/java/com/thealgorithms/scheduling/GangScheduling.java
new file mode 100644
index 000000000000..ac1ce8ddd6ae
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/GangScheduling.java
@@ -0,0 +1,61 @@
+package com.thealgorithms.scheduling;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * GangScheduling groups related tasks (gangs) to run simultaneously on multiple processors.
+ * All tasks in a gang are executed together or not at all.
+ *
+ * Use Case: Parallel computing environments where multiple threads of a program
+ * need to run concurrently for optimal performance.
+ *
+ * @author Hardvan
+ */
+public final class GangScheduling {
+
+    static class Gang {
+        String name;
+        List<String> tasks;
+
+        Gang(String name) {
+            this.name = name;
+            this.tasks = new ArrayList<>();
+        }
+
+        void addTask(String task) {
+            tasks.add(task);
+        }
+
+        List<String> getTasks() {
+            return tasks;
+        }
+    }
+
+    private final Map<String, Gang> gangs;
+
+    public GangScheduling() {
+        gangs = new HashMap<>();
+    }
+
+    public void addGang(String gangName) {
+        gangs.putIfAbsent(gangName, new Gang(gangName));
+    }
+
+    public void addTaskToGang(String gangName, String task) {
+        Gang gang = gangs.get(gangName);
+        if (gang != null) {
+            gang.addTask(task);
+        }
+    }
+
+    public Map<String, List<String>> getGangSchedules() {
+        Map<String, List<String>> schedules = new HashMap<>();
+        for (Gang gang : gangs.values()) {
+            schedules.put(gang.name, gang.getTasks());
+        }
+        return schedules;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/GangSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/GangSchedulingTest.java
new file mode 100644
index 000000000000..2e1bb4cd0e20
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/GangSchedulingTest.java
@@ -0,0 +1,52 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.Map;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class GangSchedulingTest {
+
+    private GangScheduling scheduler;
+
+    @BeforeEach
+    public void setup() {
+        scheduler = new GangScheduling();
+    }
+
+    @Test
+    public void testAddGangAndTask() {
+        scheduler.addGang("Gang1");
+        scheduler.addTaskToGang("Gang1", "Task1");
+        Map<String, List<String>> expected = Map.of("Gang1", List.of("Task1"));
+        assertEquals(expected, scheduler.getGangSchedules());
+    }
+
+    @Test
+    public void testMultipleGangs() {
+        scheduler.addGang("Gang1");
+        scheduler.addGang("Gang2");
+        scheduler.addTaskToGang("Gang1", "Task1");
+        scheduler.addTaskToGang("Gang2", "Task2");
+        Map<String, List<String>> expected = Map.of("Gang1", List.of("Task1"), "Gang2", List.of("Task2"));
+        assertEquals(expected, scheduler.getGangSchedules());
+    }
+
+    @Test
+    public void testGangWithMultipleTasks() {
+        scheduler.addGang("Gang1");
+        scheduler.addTaskToGang("Gang1", "Task1");
+        scheduler.addTaskToGang("Gang1", "Task2");
+        Map<String, List<String>> expected = Map.of("Gang1", List.of("Task1", "Task2"));
+        assertEquals(expected, scheduler.getGangSchedules());
+    }
+
+    @Test
+    public void testEmptyGangSchedule() {
+        scheduler.addGang("Gang1");
+        Map<String, List<String>> expected = Map.of("Gang1", List.of());
+        assertEquals(expected, scheduler.getGangSchedules());
+    }
+}

From 1e507068cd3d397065b3721bea14447a33052704 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 13:08:32 +0530
Subject: [PATCH 0637/1338] Enhance docs, remove `main`, add tests in
 `StackArray` (#6019)

---
 .../datastructures/stacks/StackArray.java     | 83 ++++++++++++++++++-
 .../datastructures/stacks/StackArrayTest.java | 66 ++++++++-------
 2 files changed, 117 insertions(+), 32 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java b/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java
index f98db7cc1550..9369b3fc9a64 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java
@@ -1,7 +1,13 @@
 package com.thealgorithms.datastructures.stacks;
 
 /**
- * This class implements a Stack using a regular array.
+ * Implements a generic stack using an array.
+ *
+ * <p>This stack automatically resizes when necessary, growing to accommodate additional elements and
+ * shrinking to conserve memory when its size significantly decreases.
+ *
+ * <p>Elements are pushed and popped in LIFO (last-in, first-out) order, where the last element added
+ * is the first to be removed.
  *
  * @param <T> the type of elements in this stack
  */
@@ -13,11 +19,20 @@ public class StackArray<T> implements Stack<T> {
     private T[] stackArray;
     private int top;
 
+    /**
+     * Creates a stack with a default capacity.
+     */
     @SuppressWarnings("unchecked")
     public StackArray() {
         this(DEFAULT_CAPACITY);
     }
 
+    /**
+     * Creates a stack with a specified initial capacity.
+     *
+     * @param size the initial capacity of the stack, must be greater than 0
+     * @throws IllegalArgumentException if size is less than or equal to 0
+     */
     @SuppressWarnings("unchecked")
     public StackArray(int size) {
         if (size <= 0) {
@@ -28,6 +43,11 @@ public StackArray(int size) {
         this.top = -1;
     }
 
+    /**
+     * Pushes an element onto the top of the stack. Resizes the stack if it is full.
+     *
+     * @param value the element to push
+     */
     @Override
     public void push(T value) {
         if (isFull()) {
@@ -36,6 +56,13 @@ public void push(T value) {
         stackArray[++top] = value;
     }
 
+    /**
+     * Removes and returns the element from the top of the stack. Shrinks the stack if
+     * its size is below a quarter of its capacity, but not below the default capacity.
+     *
+     * @return the element removed from the top of the stack
+     * @throws IllegalStateException if the stack is empty
+     */
     @Override
     public T pop() {
         if (isEmpty()) {
@@ -48,6 +75,12 @@ public T pop() {
         return value;
     }
 
+    /**
+     * Returns the element at the top of the stack without removing it.
+     *
+     * @return the top element of the stack
+     * @throws IllegalStateException if the stack is empty
+     */
     @Override
     public T peek() {
         if (isEmpty()) {
@@ -56,6 +89,11 @@ public T peek() {
         return stackArray[top];
     }
 
+    /**
+     * Resizes the internal array to a new capacity.
+     *
+     * @param newSize the new size of the stack array
+     */
     private void resize(int newSize) {
         @SuppressWarnings("unchecked") T[] newArray = (T[]) new Object[newSize];
         System.arraycopy(stackArray, 0, newArray, 0, top + 1);
@@ -63,21 +101,60 @@ private void resize(int newSize) {
         maxSize = newSize;
     }
 
+    /**
+     * Checks if the stack is full.
+     *
+     * @return true if the stack is full, false otherwise
+     */
     public boolean isFull() {
         return top + 1 == maxSize;
     }
 
+    /**
+     * Checks if the stack is empty.
+     *
+     * @return true if the stack is empty, false otherwise
+     */
     @Override
     public boolean isEmpty() {
         return top == -1;
     }
 
-    @Override public void makeEmpty() { // Doesn't delete elements in the array but if you call
-        top = -1; // push method after calling makeEmpty it will overwrite previous values
+    /**
+     * Empties the stack, marking it as empty without deleting elements. Elements are
+     * overwritten on subsequent pushes.
+     */
+    @Override
+    public void makeEmpty() {
+        top = -1;
     }
 
+    /**
+     * Returns the number of elements currently in the stack.
+     *
+     * @return the size of the stack
+     */
     @Override
     public int size() {
         return top + 1;
     }
+
+    /**
+     * Returns a string representation of the stack.
+     *
+     * @return a string representation of the stack
+     */
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append("StackArray [");
+        for (int i = 0; i <= top; i++) {
+            sb.append(stackArray[i]);
+            if (i < top) {
+                sb.append(", ");
+            }
+        }
+        sb.append("]");
+        return sb.toString();
+    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java
index 3cda2f54708e..74de7ad6435a 100644
--- a/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java
@@ -21,11 +21,11 @@ void testPushAndPop() {
         stack.push(4);
         stack.push(5);
 
-        Assertions.assertEquals(5, stack.pop()); // Stack follows LIFO, so 5 should be popped first
-        Assertions.assertEquals(4, stack.pop()); // Next, 4 should be popped
-        Assertions.assertEquals(3, stack.pop()); // Followed by 3
-        Assertions.assertEquals(2, stack.pop()); // Then 2
-        Assertions.assertEquals(1, stack.pop()); // Finally 1
+        Assertions.assertEquals(5, stack.pop());
+        Assertions.assertEquals(4, stack.pop());
+        Assertions.assertEquals(3, stack.pop());
+        Assertions.assertEquals(2, stack.pop());
+        Assertions.assertEquals(1, stack.pop());
     }
 
     @Test
@@ -34,34 +34,34 @@ void testPeek() {
         stack.push(20);
         stack.push(30);
 
-        Assertions.assertEquals(30, stack.peek()); // Peek should return 30, the top of the stack
-        Assertions.assertEquals(3, stack.size()); // Size should remain 3 after peek
+        Assertions.assertEquals(30, stack.peek());
+        Assertions.assertEquals(3, stack.size());
 
         stack.pop();
-        Assertions.assertEquals(20, stack.peek()); // After popping, peek should return 20
+        Assertions.assertEquals(20, stack.peek());
     }
 
     @Test
     void testIsEmpty() {
-        Assertions.assertTrue(stack.isEmpty()); // Initially, the stack should be empty
+        Assertions.assertTrue(stack.isEmpty());
         stack.push(42);
-        Assertions.assertFalse(stack.isEmpty()); // After pushing an element, the stack should not be empty
+        Assertions.assertFalse(stack.isEmpty());
         stack.pop();
-        Assertions.assertTrue(stack.isEmpty()); // After popping the only element, the stack should be empty again
+        Assertions.assertTrue(stack.isEmpty());
     }
 
     @Test
     void testResizeOnPush() {
-        StackArray<Integer> smallStack = new StackArray<>(2); // Start with a small stack size
+        StackArray<Integer> smallStack = new StackArray<>(2);
         smallStack.push(1);
         smallStack.push(2);
-        Assertions.assertTrue(smallStack.isFull()); // Initially, the stack should be full
+        Assertions.assertTrue(smallStack.isFull());
 
-        smallStack.push(3); // This push should trigger a resize
-        Assertions.assertFalse(smallStack.isFull()); // The stack should no longer be full after resize
-        Assertions.assertEquals(3, smallStack.size()); // Size should be 3 after pushing 3 elements
+        smallStack.push(3);
+        Assertions.assertFalse(smallStack.isFull());
+        Assertions.assertEquals(3, smallStack.size());
 
-        Assertions.assertEquals(3, smallStack.pop()); // LIFO behavior check
+        Assertions.assertEquals(3, smallStack.pop());
         Assertions.assertEquals(2, smallStack.pop());
         Assertions.assertEquals(1, smallStack.pop());
     }
@@ -74,13 +74,13 @@ void testResizeOnPop() {
         stack.push(3);
         stack.push(4);
 
-        stack.pop(); // Removing elements should trigger a resize when less than 1/4 of the stack is used
         stack.pop();
         stack.pop();
-        Assertions.assertEquals(1, stack.size()); // After popping, only one element should remain
+        stack.pop();
+        Assertions.assertEquals(1, stack.size());
 
         stack.pop();
-        Assertions.assertTrue(stack.isEmpty()); // The stack should be empty now
+        Assertions.assertTrue(stack.isEmpty());
     }
 
     @Test
@@ -90,32 +90,40 @@ void testMakeEmpty() {
         stack.push(3);
         stack.makeEmpty();
 
-        Assertions.assertTrue(stack.isEmpty()); // The stack should be empty after calling makeEmpty
-        Assertions.assertThrows(IllegalStateException.class, stack::pop); // Popping from empty stack should throw exception
+        Assertions.assertTrue(stack.isEmpty());
+        Assertions.assertThrows(IllegalStateException.class, stack::pop);
     }
 
     @Test
     void testPopEmptyStackThrowsException() {
-        Assertions.assertThrows(IllegalStateException.class, stack::pop); // Popping from an empty stack should throw an exception
+        Assertions.assertThrows(IllegalStateException.class, stack::pop);
     }
 
     @Test
     void testPeekEmptyStackThrowsException() {
-        Assertions.assertThrows(IllegalStateException.class, stack::peek); // Peeking into an empty stack should throw an exception
+        Assertions.assertThrows(IllegalStateException.class, stack::peek);
     }
 
     @Test
     void testConstructorWithInvalidSizeThrowsException() {
-        Assertions.assertThrows(IllegalArgumentException.class, () -> new StackArray<>(0)); // Size 0 is invalid
-        Assertions.assertThrows(IllegalArgumentException.class, () -> new StackArray<>(-5)); // Negative size is invalid
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new StackArray<>(0));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new StackArray<>(-5));
     }
 
     @Test
     void testDefaultConstructor() {
-        StackArray<Integer> defaultStack = new StackArray<>(); // Using default constructor
-        Assertions.assertEquals(0, defaultStack.size()); // Initially, size should be 0
+        StackArray<Integer> defaultStack = new StackArray<>();
+        Assertions.assertEquals(0, defaultStack.size());
 
         defaultStack.push(1);
-        Assertions.assertEquals(1, defaultStack.size()); // After pushing, size should be 1
+        Assertions.assertEquals(1, defaultStack.size());
+    }
+
+    @Test
+    void testToString() {
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+        Assertions.assertEquals("StackArray [1, 2, 3]", stack.toString());
     }
 }

From ab9a55272dbd0047c648463e37e8da017ffa6a35 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 13:44:29 +0530
Subject: [PATCH 0638/1338] Enhance docs, remove `main`, add tests in
 `NodeStack` (#6017)

---
 DIRECTORY.md                                  |   1 +
 .../datastructures/stacks/NodeStack.java      | 162 ++++++------------
 .../datastructures/stacks/NodeStackTest.java  |  85 +++++++++
 3 files changed, 141 insertions(+), 107 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index ad893d45f5dc..061cf93a4251 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -866,6 +866,7 @@
               * [QueueByTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java)
               * [QueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java)
             * stacks
+              * [NodeStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java)
               * [StackArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java)
               * [StackArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java)
               * [StackOfLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java b/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java
index 7c4f334cd617..384cf3c0395a 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java
@@ -1,161 +1,109 @@
 package com.thealgorithms.datastructures.stacks;
 
 /**
- * Implementation of a stack using nodes. Unlimited size, no arraylist.
+ * A stack implementation using linked nodes, supporting unlimited size without an ArrayList.
  *
- * @author Kyler Smith, 2017
+ * <p>Each node in the stack contains data of generic type {@code Item}, along with references
+ * to the next and previous nodes, supporting typical stack operations.
+ *
+ * <p>The stack follows a Last-In-First-Out (LIFO) order where elements added last are
+ * removed first. Supported operations include push, pop, and peek.
+ *
+ * @param <Item> the type of elements held in this stack
  */
 public class NodeStack<Item> {
 
     /**
-     * Entry point for the program.
+     * Node class representing each element in the stack.
      */
-    public static void main(String[] args) {
-        NodeStack<Integer> stack = new NodeStack<Integer>();
-
-        stack.push(3);
-        stack.push(4);
-        stack.push(5);
-        System.out.println("Testing :");
-        stack.print(); // prints : 5 4 3
+    private class Node {
+        Item data;
+        Node previous;
 
-        Integer x = stack.pop(); // x = 5
-        stack.push(1);
-        stack.push(8);
-        Integer y = stack.peek(); // y = 8
-        System.out.println("Testing :");
-        stack.print(); // prints : 8 1 4 3
-
-        System.out.println("Testing :");
-        System.out.println("x : " + x);
-        System.out.println("y : " + y);
+        Node(Item data) {
+            this.data = data;
+            this.previous = null;
+        }
     }
 
-    /**
-     * Information each node should contain.
-     *
-     * @value data : information of the value in the node
-     * @value head : the head of the stack
-     * @value next : the next value from this node
-     * @value previous : the last value from this node
-     * @value size : size of the stack
-     */
-    private Item data;
-
-    private static NodeStack<?> head;
-    private NodeStack<?> previous;
-    private static int size = 0;
+    private Node head; // Top node in the stack
+    private int size; // Number of elements in the stack
 
     /**
-     * Constructors for the NodeStack.
+     * Constructs an empty NodeStack.
      */
     public NodeStack() {
-    }
-
-    private NodeStack(Item item) {
-        this.data = item;
+        head = null;
+        size = 0;
     }
 
     /**
-     * Put a value onto the stack.
+     * Pushes an item onto the stack.
      *
-     * @param item : value to be put on the stack.
+     * @param item the item to be pushed onto the stack
      */
     public void push(Item item) {
-        NodeStack<Item> newNs = new NodeStack<Item>(item);
-
-        if (this.isEmpty()) {
-            NodeStack.setHead(new NodeStack<>(item));
-            newNs.setNext(null);
-            newNs.setPrevious(null);
-        } else {
-            newNs.setPrevious(NodeStack.head);
-            NodeStack.head.setNext(newNs);
-            NodeStack.setHead(newNs);
-        }
-
-        NodeStack.setSize(NodeStack.getSize() + 1);
+        Node newNode = new Node(item);
+        newNode.previous = head;
+        head = newNode;
+        size++;
     }
 
     /**
-     * Value to be taken off the stack.
+     * Removes and returns the item at the top of the stack.
      *
-     * @return item : value that is returned.
+     * @return the item at the top of the stack, or {@code null} if the stack is empty
+     * @throws IllegalStateException if the stack is empty
      */
     public Item pop() {
-        Item item = (Item) NodeStack.head.getData();
-
-        NodeStack.setHead(NodeStack.head.getPrevious());
-        NodeStack.head.setNext(null);
-
-        NodeStack.setSize(NodeStack.getSize() - 1);
-
-        return item;
+        if (isEmpty()) {
+            throw new IllegalStateException("Cannot pop from an empty stack.");
+        }
+        Item data = head.data;
+        head = head.previous;
+        size--;
+        return data;
     }
 
     /**
-     * Value that is next to be taken off the stack.
+     * Returns the item at the top of the stack without removing it.
      *
-     * @return item : the next value that would be popped off the stack.
+     * @return the item at the top of the stack, or {@code null} if the stack is empty
+     * @throws IllegalStateException if the stack is empty
      */
     public Item peek() {
-        return (Item) NodeStack.head.getData();
+        if (isEmpty()) {
+            throw new IllegalStateException("Cannot peek from an empty stack.");
+        }
+        return head.data;
     }
 
     /**
-     * If the stack is empty or there is a value in.
+     * Checks whether the stack is empty.
      *
-     * @return boolean : whether or not the stack has anything in it.
+     * @return {@code true} if the stack has no elements, {@code false} otherwise
      */
     public boolean isEmpty() {
-        return NodeStack.getSize() == 0;
+        return head == null;
     }
 
     /**
-     * Returns the size of the stack.
+     * Returns the number of elements currently in the stack.
      *
-     * @return int : number of values in the stack.
+     * @return the size of the stack
      */
     public int size() {
-        return NodeStack.getSize();
+        return size;
     }
 
     /**
-     * Print the contents of the stack in the following format.
-     *
-     * <p>
-     * x <- head (next out) y z <- tail (first in) . . .
+     * Prints the contents of the stack from top to bottom.
      */
     public void print() {
-        for (NodeStack<?> n = NodeStack.head; n != null; n = n.previous) {
-            System.out.println(n.getData().toString());
+        Node current = head;
+        while (current != null) {
+            System.out.println(current.data);
+            current = current.previous;
         }
     }
-
-    private static void setHead(NodeStack<?> ns) {
-        NodeStack.head = ns;
-    }
-
-    private void setNext(NodeStack<?> next) {
-    }
-
-    private NodeStack<?> getPrevious() {
-        return previous;
-    }
-
-    private void setPrevious(NodeStack<?> previous) {
-        this.previous = previous;
-    }
-
-    private static int getSize() {
-        return size;
-    }
-
-    private static void setSize(int size) {
-        NodeStack.size = size;
-    }
-
-    private Item getData() {
-        return this.data;
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java
new file mode 100644
index 000000000000..e05319359815
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java
@@ -0,0 +1,85 @@
+package com.thealgorithms.datastructures.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class NodeStackTest {
+
+    @Test
+    void testPush() {
+        NodeStack<Integer> stack = new NodeStack<>();
+        stack.push(10);
+        stack.push(20);
+        assertEquals(20, stack.peek(), "Top element should be 20 after pushing 10 and 20.");
+    }
+
+    @Test
+    void testPop() {
+        NodeStack<String> stack = new NodeStack<>();
+        stack.push("First");
+        stack.push("Second");
+        assertEquals("Second", stack.pop(), "Pop should return 'Second', the last pushed element.");
+        assertEquals("First", stack.pop(), "Pop should return 'First' after 'Second' is removed.");
+    }
+
+    @Test
+    void testPopOnEmptyStack() {
+        NodeStack<Double> stack = new NodeStack<>();
+        assertThrows(IllegalStateException.class, stack::pop, "Popping an empty stack should throw IllegalStateException.");
+    }
+
+    @Test
+    void testPeek() {
+        NodeStack<Integer> stack = new NodeStack<>();
+        stack.push(5);
+        stack.push(15);
+        assertEquals(15, stack.peek(), "Peek should return 15, the top element.");
+        stack.pop();
+        assertEquals(5, stack.peek(), "Peek should return 5 after 15 is popped.");
+    }
+
+    @Test
+    void testPeekOnEmptyStack() {
+        NodeStack<String> stack = new NodeStack<>();
+        assertThrows(IllegalStateException.class, stack::peek, "Peeking an empty stack should throw IllegalStateException.");
+    }
+
+    @Test
+    void testIsEmpty() {
+        NodeStack<Character> stack = new NodeStack<>();
+        assertTrue(stack.isEmpty(), "Newly initialized stack should be empty.");
+        stack.push('A');
+        assertFalse(stack.isEmpty(), "Stack should not be empty after a push operation.");
+        stack.pop();
+        assertTrue(stack.isEmpty(), "Stack should be empty after popping the only element.");
+    }
+
+    @Test
+    void testSize() {
+        NodeStack<Integer> stack = new NodeStack<>();
+        assertEquals(0, stack.size(), "Size of empty stack should be 0.");
+        stack.push(3);
+        stack.push(6);
+        assertEquals(2, stack.size(), "Size should be 2 after pushing two elements.");
+        stack.pop();
+        assertEquals(1, stack.size(), "Size should be 1 after popping one element.");
+        stack.pop();
+        assertEquals(0, stack.size(), "Size should be 0 after popping all elements.");
+    }
+
+    @Test
+    void testPrint() {
+        NodeStack<Integer> stack = new NodeStack<>();
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+
+        // Output verification would ideally be handled through a different means
+        // but you can print as a basic check to confirm method runs without errors.
+        stack.print();
+    }
+}

From e1a01559669a58dc3d82e70fdc0d412ceb2eca00 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 13:48:38 +0530
Subject: [PATCH 0639/1338] Enhance docs, add tests in `GenericArrayListQueue`
 (#6016)

---
 .../queues/GenericArrayListQueue.java         | 31 +++++----
 .../queues/GenericArrayListQueueTest.java     | 69 +++++++++++++++----
 2 files changed, 74 insertions(+), 26 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java
index 2a3a5a2c38e2..865da7bffc9f 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java
@@ -4,43 +4,46 @@
 import java.util.List;
 
 /**
- * This class implements a GenericArrayListQueue.
+ * This class implements a GenericArrayListQueue, a queue data structure that
+ * holds elements of any type specified at runtime, allowing flexibility in the type
+ * of elements it stores.
  *
- * A GenericArrayListQueue data structure functions the same as any
- * specific-typed queue. The GenericArrayListQueue holds elements of types
- * to-be-specified at runtime. The elements that are added first are the first
- * to be removed (FIFO). New elements are added to the back/rear of the queue.
+ * <p>The GenericArrayListQueue operates on a First-In-First-Out (FIFO) basis, where
+ * elements added first are the first to be removed. New elements are added to the back
+ * (or rear) of the queue, while removal of elements occurs from the front.
+ *
+ * @param <T> The type of elements held in this queue.
  */
 public class GenericArrayListQueue<T> {
 
     /**
-     * The generic List for the queue. T is the generic element type.
+     * A list that stores the queue's elements in insertion order.
      */
     private final List<T> elementList = new ArrayList<>();
 
     /**
      * Checks if the queue is empty.
      *
-     * @return True if the queue is empty, false otherwise.
+     * @return {@code true} if the queue has no elements; {@code false} otherwise.
      */
-    private boolean isEmpty() {
+    public boolean isEmpty() {
         return elementList.isEmpty();
     }
 
     /**
-     * Returns the element at the front of the queue without removing it.
+     * Retrieves, but does not remove, the element at the front of the queue.
      *
-     * @return The element at the front of the queue, or null if the queue is empty.
+     * @return The element at the front of the queue, or {@code null} if the queue is empty.
      */
     public T peek() {
         return isEmpty() ? null : elementList.getFirst();
     }
 
     /**
-     * Inserts an element of type T to the back of the queue.
+     * Inserts an element at the back of the queue.
      *
-     * @param element the element to be added to the queue.
-     * @return True if the element was added successfully.
+     * @param element The element to be added to the queue.
+     * @return {@code true} if the element was successfully added.
      */
     public boolean add(T element) {
         return elementList.add(element);
@@ -49,7 +52,7 @@ public boolean add(T element) {
     /**
      * Retrieves and removes the element at the front of the queue.
      *
-     * @return The element removed from the front of the queue, or null if the queue is empty.
+     * @return The element removed from the front of the queue, or {@code null} if the queue is empty.
      */
     public T poll() {
         return isEmpty() ? null : elementList.removeFirst();
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java b/src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java
index bb76b8317e62..b19513e19ad9 100644
--- a/src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.queues;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -13,43 +14,87 @@ void testAdd() {
         GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
         assertTrue(queue.add(10));
         assertTrue(queue.add(20));
+        assertEquals(10, queue.peek()); // Ensure the first added element is at the front
     }
 
     @Test
     void testPeek() {
         GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
-        assertNull(queue.peek());
+        assertNull(queue.peek(), "Peek should return null for an empty queue");
 
         queue.add(10);
         queue.add(20);
 
-        assertEquals(10, queue.peek());
+        assertEquals(10, queue.peek(), "Peek should return the first element (10)");
         queue.poll();
-        assertEquals(20, queue.peek());
+        assertEquals(20, queue.peek(), "Peek should return the next element (20) after poll");
     }
 
     @Test
     void testPoll() {
         GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
-        assertNull(queue.poll());
+        assertNull(queue.poll(), "Poll should return null for an empty queue");
 
         queue.add(10);
         queue.add(20);
 
-        assertEquals(10, queue.poll());
-        assertEquals(20, queue.poll());
-        assertNull(queue.poll());
+        assertEquals(10, queue.poll(), "Poll should return and remove the first element (10)");
+        assertEquals(20, queue.poll(), "Poll should return and remove the next element (20)");
+        assertNull(queue.poll(), "Poll should return null when queue is empty after removals");
     }
 
     @Test
     void testIsEmpty() {
         GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
-        assertNull(queue.peek());
-        assertNull(queue.poll());
+        assertTrue(queue.isEmpty(), "Queue should initially be empty");
 
         queue.add(30);
-        assertEquals(30, queue.peek());
-        assertEquals(30, queue.poll());
-        assertNull(queue.peek());
+        assertFalse(queue.isEmpty(), "Queue should not be empty after adding an element");
+        queue.poll();
+        assertTrue(queue.isEmpty(), "Queue should be empty after removing the only element");
+    }
+
+    @Test
+    void testClearQueueAndReuse() {
+        GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
+        queue.add(5);
+        queue.add(10);
+        queue.poll();
+        queue.poll(); // Remove all elements
+
+        assertTrue(queue.isEmpty(), "Queue should be empty after all elements are removed");
+        assertNull(queue.peek(), "Peek should return null on an empty queue after clear");
+        assertTrue(queue.add(15), "Queue should be reusable after being emptied");
+        assertEquals(15, queue.peek(), "Newly added element should be accessible in the empty queue");
+    }
+
+    @Test
+    void testOrderMaintained() {
+        GenericArrayListQueue<String> queue = new GenericArrayListQueue<>();
+        queue.add("First");
+        queue.add("Second");
+        queue.add("Third");
+
+        assertEquals("First", queue.poll(), "Order should be maintained; expected 'First'");
+        assertEquals("Second", queue.poll(), "Order should be maintained; expected 'Second'");
+        assertEquals("Third", queue.poll(), "Order should be maintained; expected 'Third'");
+    }
+
+    @Test
+    void testVariousDataTypes() {
+        GenericArrayListQueue<Double> queue = new GenericArrayListQueue<>();
+        queue.add(1.1);
+        queue.add(2.2);
+
+        assertEquals(1.1, queue.peek(), "Queue should handle Double data type correctly");
+        assertEquals(1.1, queue.poll(), "Poll should return correct Double value");
+        assertEquals(2.2, queue.peek(), "Peek should show next Double value in the queue");
+    }
+
+    @Test
+    void testEmptyPollAndPeekBehavior() {
+        GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<>();
+        assertNull(queue.peek(), "Peek on an empty queue should return null");
+        assertNull(queue.poll(), "Poll on an empty queue should return null");
     }
 }

From 9dbdaf6afbff7a05bf17ba46f9a978a4d8704dfd Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 13:56:21 +0530
Subject: [PATCH 0640/1338] Enhance docs, add tests in
 `RotateSinglyLinkedLists` (#6011)

---
 .../lists/RotateSinglyLinkedLists.java        |  38 +++++-
 .../lists/RotateSinglyLinkedListsTest.java    | 109 ++++++++++++------
 2 files changed, 106 insertions(+), 41 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java b/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java
index e7ea95d3f037..7676cc343653 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java
@@ -1,11 +1,43 @@
 package com.thealgorithms.datastructures.lists;
 
 /**
- * Rotate a list
- * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
+ * The RotateSinglyLinkedLists class provides a method to rotate a singly linked list
+ * to the right by a specified number of positions.
+ * <p>
+ * In a right rotation by `k` steps, each node in the list moves `k` positions to the right.
+ * Nodes that are rotated off the end of the list are placed back at the beginning.
+ * </p>
+ * <p>
+ * Example:
+ * Given linked list: 1 -> 2 -> 3 -> 4 -> 5 and k = 2, the output will be:
+ * 4 -> 5 -> 1 -> 2 -> 3.
+ * </p>
+ * <p>
+ * Edge Cases:
+ * <ul>
+ *   <li>If the list is empty, returns null.</li>
+ *   <li>If `k` is 0 or a multiple of the list length, the list remains unchanged.</li>
+ * </ul>
+ * </p>
+ * <p>
+ * Complexity:
+ * <ul>
+ *   <li>Time Complexity: O(n), where n is the number of nodes in the linked list.</li>
+ *   <li>Space Complexity: O(1), as we only use a constant amount of additional space.</li>
+ * </ul>
+ * </p>
+ *
+ * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
-
 public class RotateSinglyLinkedLists {
+
+    /**
+     * Rotates a singly linked list to the right by `k` positions.
+     *
+     * @param head The head node of the singly linked list.
+     * @param k The number of positions to rotate the list to the right.
+     * @return The head of the rotated linked list.
+     */
     public Node rotateRight(Node head, int k) {
         if (head == null || head.next == null || k == 0) {
             return head;
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java b/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
index 8b2ae424364e..70c0dfccafa4 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
@@ -6,67 +6,100 @@
 import org.junit.jupiter.api.Test;
 
 /**
- * Test cases for RotateSinglyLinkedLists
+ * Test cases for RotateSinglyLinkedLists.
  * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
 public class RotateSinglyLinkedListsTest {
 
+    private final RotateSinglyLinkedLists rotator = new RotateSinglyLinkedLists();
+
+    // Helper method to create a linked list from an array of values
+    private Node createLinkedList(int[] values) {
+        if (values.length == 0) {
+            return null;
+        }
+
+        Node head = new Node(values[0]);
+        Node current = head;
+        for (int i = 1; i < values.length; i++) {
+            current.next = new Node(values[i]);
+            current = current.next;
+        }
+        return head;
+    }
+
+    // Helper method to convert a linked list to a string for easy comparison
+    private String linkedListToString(Node head) {
+        StringBuilder sb = new StringBuilder();
+        Node current = head;
+        while (current != null) {
+            sb.append(current.value);
+            if (current.next != null) {
+                sb.append(" -> ");
+            }
+            current = current.next;
+        }
+        return sb.toString();
+    }
+
     @Test
     public void testRotateRightEmptyList() {
-        RotateSinglyLinkedLists rotator = new RotateSinglyLinkedLists();
-
-        // Test case: Rotate an empty list
+        // Rotate an empty list
         assertNull(rotator.rotateRight(null, 2));
     }
 
     @Test
     public void testRotateRightSingleNodeList() {
-        RotateSinglyLinkedLists rotator = new RotateSinglyLinkedLists();
-
-        // Test case: Rotate a list with one element
+        // Rotate a list with a single element
         Node singleNode = new Node(5);
         Node rotatedSingleNode = rotator.rotateRight(singleNode, 3);
-        assertEquals(5, rotatedSingleNode.value);
-        assertNull(rotatedSingleNode.next);
+        assertEquals("5", linkedListToString(rotatedSingleNode));
     }
 
     @Test
     public void testRotateRightMultipleElementsList() {
-        RotateSinglyLinkedLists rotator = new RotateSinglyLinkedLists();
+        // Rotate a list with multiple elements (rotate by 2)
+        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5});
+        Node rotated = rotator.rotateRight(head, 2);
+        assertEquals("4 -> 5 -> 1 -> 2 -> 3", linkedListToString(rotated));
+    }
 
-        // Test case: Rotate a list with multiple elements (Rotate by 2)
-        Node head = new Node(1);
-        head.next = new Node(2);
-        head.next.next = new Node(3);
-        head.next.next.next = new Node(4);
-        head.next.next.next.next = new Node(5);
+    @Test
+    public void testRotateRightFullRotation() {
+        // Rotate by more than the length of the list
+        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5});
+        Node rotated = rotator.rotateRight(head, 7);
+        assertEquals("4 -> 5 -> 1 -> 2 -> 3", linkedListToString(rotated));
+    }
 
-        Node rotated1 = rotator.rotateRight(head, 2);
-        assertEquals(4, rotated1.value);
-        assertEquals(5, rotated1.next.value);
-        assertEquals(1, rotated1.next.next.value);
-        assertEquals(2, rotated1.next.next.next.value);
-        assertEquals(3, rotated1.next.next.next.next.value);
-        assertNull(rotated1.next.next.next.next.next);
+    @Test
+    public void testRotateRightZeroRotation() {
+        // Rotate a list by k = 0 (no rotation)
+        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5});
+        Node rotated = rotator.rotateRight(head, 0);
+        assertEquals("1 -> 2 -> 3 -> 4 -> 5", linkedListToString(rotated));
     }
 
     @Test
-    public void testRotateRightFullRotation() {
-        RotateSinglyLinkedLists rotator = new RotateSinglyLinkedLists();
+    public void testRotateRightByListLength() {
+        // Rotate a list by k equal to list length (no change)
+        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5});
+        Node rotated = rotator.rotateRight(head, 5);
+        assertEquals("1 -> 2 -> 3 -> 4 -> 5", linkedListToString(rotated));
+    }
 
-        // Test case: Rotate a list with multiple elements (Full rotation)
-        Node head = new Node(1);
-        head.next = new Node(2);
-        head.next.next = new Node(3);
-        head.next.next.next = new Node(4);
-        head.next.next.next.next = new Node(5);
+    @Test
+    public void testRotateRightByMultipleOfListLength() {
+        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5});
+        Node rotated = rotator.rotateRight(head, 10); // k = 2 * list length
+        assertEquals("1 -> 2 -> 3 -> 4 -> 5", linkedListToString(rotated));
+    }
 
-        Node rotated3 = rotator.rotateRight(head, 7);
-        assertEquals(4, rotated3.value);
-        assertEquals(5, rotated3.next.value);
-        assertEquals(1, rotated3.next.next.value);
-        assertEquals(2, rotated3.next.next.next.value);
-        assertEquals(3, rotated3.next.next.next.next.value);
-        assertNull(rotated3.next.next.next.next.next);
+    @Test
+    public void testRotateRightLongerList() {
+        // Rotate a longer list by a smaller k
+        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9});
+        Node rotated = rotator.rotateRight(head, 4);
+        assertEquals("6 -> 7 -> 8 -> 9 -> 1 -> 2 -> 3 -> 4 -> 5", linkedListToString(rotated));
     }
 }

From 82dee61701555677ce3bd1e49718c0cfcef98589 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:09:31 +0530
Subject: [PATCH 0641/1338] Add TokenBucket algorithm (#5840)

---
 DIRECTORY.md                                  |  2 +
 .../datastructures/queues/TokenBucket.java    | 61 +++++++++++++
 .../queues/TokenBucketTest.java               | 90 +++++++++++++++++++
 3 files changed, 153 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/queues/TokenBucket.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/queues/TokenBucketTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 061cf93a4251..fa9c26535c9b 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -201,6 +201,7 @@
               * [PriorityQueues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java)
               * [Queue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/Queue.java)
               * [QueueByTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java)
+              * [TokenBucket](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/TokenBucket.java)
             * stacks
               * [NodeStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java)
               * [ReverseStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java)
@@ -865,6 +866,7 @@
               * [PriorityQueuesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java)
               * [QueueByTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java)
               * [QueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java)
+              * [TokenBucketTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/TokenBucketTest.java)
             * stacks
               * [NodeStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java)
               * [StackArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/TokenBucket.java b/src/main/java/com/thealgorithms/datastructures/queues/TokenBucket.java
new file mode 100644
index 000000000000..999c963fab93
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/queues/TokenBucket.java
@@ -0,0 +1,61 @@
+package com.thealgorithms.datastructures.queues;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * TokenBucket implements a token bucket rate limiter algorithm.
+ * This class is used to control the rate of requests in a distributed system.
+ * It allows a certain number of requests (tokens) to be processed in a time frame,
+ * based on the defined refill rate.
+ *
+ * Applications: Computer networks, API rate limiting, distributed systems, etc.
+ *
+ * @author Hardvan
+ */
+public final class TokenBucket {
+    private final int maxTokens;
+    private final int refillRate; // tokens per second
+    private int tokens;
+    private long lastRefill; // Timestamp in nanoseconds
+
+    /**
+     * Constructs a TokenBucket instance.
+     *
+     * @param maxTokens  Maximum number of tokens the bucket can hold.
+     * @param refillRate The rate at which tokens are refilled (tokens per second).
+     */
+    public TokenBucket(int maxTokens, int refillRate) {
+        this.maxTokens = maxTokens;
+        this.refillRate = refillRate;
+        this.tokens = maxTokens;
+        this.lastRefill = System.nanoTime();
+    }
+
+    /**
+     * Attempts to allow a request based on the available tokens.
+     * If a token is available, it decrements the token count and allows the request.
+     * Otherwise, the request is denied.
+     *
+     * @return true if the request is allowed, false if the request is denied.
+     */
+    public synchronized boolean allowRequest() {
+        refillTokens();
+        if (tokens > 0) {
+            tokens--;
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Refills the tokens based on the time elapsed since the last refill.
+     * The number of tokens to be added is calculated based on the elapsed time
+     * and the refill rate, ensuring the total does not exceed maxTokens.
+     */
+    private void refillTokens() {
+        long now = System.nanoTime();
+        long tokensToAdd = (now - lastRefill) / TimeUnit.SECONDS.toNanos(1) * refillRate;
+        tokens = Math.min(maxTokens, tokens + (int) tokensToAdd);
+        lastRefill = now;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/TokenBucketTest.java b/src/test/java/com/thealgorithms/datastructures/queues/TokenBucketTest.java
new file mode 100644
index 000000000000..959ea8724f8b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/queues/TokenBucketTest.java
@@ -0,0 +1,90 @@
+package com.thealgorithms.datastructures.queues;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class TokenBucketTest {
+
+    @Test
+    public void testRateLimiter() throws InterruptedException {
+        TokenBucket bucket = new TokenBucket(5, 1);
+        for (int i = 0; i < 5; i++) {
+            assertTrue(bucket.allowRequest());
+        }
+        assertFalse(bucket.allowRequest());
+        Thread.sleep(1000);
+        assertTrue(bucket.allowRequest());
+    }
+
+    @Test
+    public void testRateLimiterWithExceedingRequests() throws InterruptedException {
+        TokenBucket bucket = new TokenBucket(3, 1);
+
+        for (int i = 0; i < 3; i++) {
+            assertTrue(bucket.allowRequest());
+        }
+        assertFalse(bucket.allowRequest());
+
+        Thread.sleep(1000);
+        assertTrue(bucket.allowRequest());
+        assertFalse(bucket.allowRequest());
+    }
+
+    @Test
+    public void testRateLimiterMultipleRefills() throws InterruptedException {
+        TokenBucket bucket = new TokenBucket(2, 1);
+
+        assertTrue(bucket.allowRequest());
+        assertTrue(bucket.allowRequest());
+        assertFalse(bucket.allowRequest());
+
+        Thread.sleep(1000);
+        assertTrue(bucket.allowRequest());
+
+        Thread.sleep(1000);
+        assertTrue(bucket.allowRequest());
+        assertFalse(bucket.allowRequest());
+    }
+
+    @Test
+    public void testRateLimiterEmptyBucket() {
+        TokenBucket bucket = new TokenBucket(0, 1);
+
+        assertFalse(bucket.allowRequest());
+    }
+
+    @Test
+    public void testRateLimiterWithHighRefillRate() throws InterruptedException {
+        TokenBucket bucket = new TokenBucket(5, 10);
+
+        for (int i = 0; i < 5; i++) {
+            assertTrue(bucket.allowRequest());
+        }
+
+        assertFalse(bucket.allowRequest());
+
+        Thread.sleep(1000);
+
+        for (int i = 0; i < 5; i++) {
+            assertTrue(bucket.allowRequest());
+        }
+    }
+
+    @Test
+    public void testRateLimiterWithSlowRequests() throws InterruptedException {
+        TokenBucket bucket = new TokenBucket(5, 1);
+
+        for (int i = 0; i < 5; i++) {
+            assertTrue(bucket.allowRequest());
+        }
+
+        Thread.sleep(1000);
+        assertTrue(bucket.allowRequest());
+
+        Thread.sleep(2000);
+        assertTrue(bucket.allowRequest());
+        assertTrue(bucket.allowRequest());
+    }
+}

From 788f4d8b2805f9b9b1b83f6e10bcfdd70bc56e52 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:16:40 +0530
Subject: [PATCH 0642/1338] Enhance docs, add more tests in
 `NonRepeatingNumberFinder` (#5843)

---
 .../NonRepeatingNumberFinder.java             | 20 +++++++++--
 .../NonRepeatingNumberFinderTest.java         | 33 +++++++++++++------
 2 files changed, 41 insertions(+), 12 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java b/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java
index 07476a8b9476..17e1a73ec062 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java
@@ -1,14 +1,30 @@
 package com.thealgorithms.bitmanipulation;
 
 /**
- * Find Non Repeating Number
+ * A utility class to find the non-repeating number in an array where every other number repeats.
+ * This class contains a method to identify the single unique number using bit manipulation.
+ *
+ * The solution leverages the properties of the XOR operation, which states that:
+ * - x ^ x = 0 for any integer x (a number XORed with itself is zero)
+ * - x ^ 0 = x for any integer x (a number XORed with zero is the number itself)
+ *
+ * Using these properties, we can find the non-repeating number in linear time with constant space.
+ *
+ * Example:
+ * Given the input array [2, 3, 5, 2, 3], the output will be 5 since it does not repeat.
+ *
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
-
 public final class NonRepeatingNumberFinder {
     private NonRepeatingNumberFinder() {
     }
 
+    /**
+     * Finds the non-repeating number in the given array.
+     *
+     * @param arr an array of integers where every number except one appears twice
+     * @return the integer that appears only once in the array or 0 if the array is empty
+     */
     public static int findNonRepeatingNumber(int[] arr) {
         int result = 0;
         for (int num : arr) {
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java b/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
index 1addde057181..fe2136fd7f04 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
@@ -2,22 +2,35 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 /**
  * Test case for Non Repeating Number Finder
+ * This test class validates the functionality of the
+ * NonRepeatingNumberFinder by checking various scenarios.
+ *
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
-
 class NonRepeatingNumberFinderTest {
 
-    @Test
-    void testNonRepeatingNumberFinder() {
-        int[] arr = {1, 2, 1, 2, 6};
-        assertEquals(6, NonRepeatingNumberFinder.findNonRepeatingNumber(arr));
-        int[] arr1 = {1, 2, 1, 2};
-        assertEquals(0, NonRepeatingNumberFinder.findNonRepeatingNumber(arr1));
-        int[] arr2 = {12};
-        assertEquals(12, NonRepeatingNumberFinder.findNonRepeatingNumber(arr2));
+    @ParameterizedTest
+    @MethodSource("testCases")
+    void testNonRepeatingNumberFinder(int[] arr, int expected) {
+        assertEquals(expected, NonRepeatingNumberFinder.findNonRepeatingNumber(arr));
+    }
+
+    private static Arguments[] testCases() {
+        return new Arguments[] {
+            Arguments.of(new int[] {1, 2, 1, 2, 6}, 6), Arguments.of(new int[] {1, 2, 1, 2}, 0), // All numbers repeat
+            Arguments.of(new int[] {12}, 12), // Single non-repeating number
+            Arguments.of(new int[] {3, 5, 3, 4, 4}, 5), // More complex case
+            Arguments.of(new int[] {7, 8, 7, 9, 8, 10, 10}, 9), // Non-repeating in the middle
+            Arguments.of(new int[] {0, -1, 0, -1, 2}, 2), // Testing with negative numbers
+            Arguments.of(new int[] {Integer.MAX_VALUE, 1, 1}, Integer.MAX_VALUE), // Edge case with max int
+            Arguments.of(new int[] {2, 2, 3, 3, 4, 5, 4}, 5), // Mixed duplicates
+            Arguments.of(new int[] {}, 0) // Edge case: empty array (should be handled as per design)
+        };
     }
 }

From 009c2b38afe27a47f1132d5c8909b585d9c830df Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:20:22 +0530
Subject: [PATCH 0643/1338] Enhance docs, add more tests in `ArrayCombination`
 (#5842)

---
 .../bitmanipulation/IsPowerTwo.java           | 18 ++++++-
 .../bitmanipulation/IsPowerTwoTest.java       | 54 ++++++++++++-------
 2 files changed, 51 insertions(+), 21 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java b/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java
index 54d28d4d22cc..4cdf3c6faa3e 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java
@@ -1,13 +1,27 @@
 package com.thealgorithms.bitmanipulation;
 
 /**
- * Is number power of 2
+ * Utility class for checking if a number is a power of two.
+ * A power of two is a number that can be expressed as 2^n where n is a non-negative integer.
+ * This class provides a method to determine if a given integer is a power of two using bit manipulation.
+ *
  * @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
-
 public final class IsPowerTwo {
     private IsPowerTwo() {
     }
+
+    /**
+     * Checks if the given integer is a power of two.
+     *
+     * A number is considered a power of two if it is greater than zero and
+     * has exactly one '1' bit in its binary representation. This method
+     * uses the property that for any power of two (n), the expression
+     * (n & (n - 1)) will be zero.
+     *
+     * @param number the integer to check
+     * @return true if the number is a power of two, false otherwise
+     */
     public static boolean isPowerTwo(int number) {
         if (number <= 0) {
             return false;
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java b/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java
index 27bc93c31ae4..ffd9e4ef176d 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java
@@ -3,7 +3,10 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 /**
  * Test case for IsPowerTwo class
@@ -11,25 +14,38 @@
  */
 
 public class IsPowerTwoTest {
-    @Test
-    public void testIsPowerTwo() {
-        // test some positive powers of 2
-        assertTrue(IsPowerTwo.isPowerTwo(1));
-        assertTrue(IsPowerTwo.isPowerTwo(2));
-        assertTrue(IsPowerTwo.isPowerTwo(4));
-        assertTrue(IsPowerTwo.isPowerTwo(16));
-        assertTrue(IsPowerTwo.isPowerTwo(1024));
 
-        // test some negative numbers
-        assertFalse(IsPowerTwo.isPowerTwo(-1));
-        assertFalse(IsPowerTwo.isPowerTwo(-2));
-        assertFalse(IsPowerTwo.isPowerTwo(-4));
+    @ParameterizedTest
+    @MethodSource("provideNumbersForPowerTwo")
+    public void testIsPowerTwo(int number, boolean expected) {
+        if (expected) {
+            assertTrue(IsPowerTwo.isPowerTwo(number));
+        } else {
+            assertFalse(IsPowerTwo.isPowerTwo(number));
+        }
+    }
 
-        // test some numbers that are not powers of 2
-        assertFalse(IsPowerTwo.isPowerTwo(0));
-        assertFalse(IsPowerTwo.isPowerTwo(3));
-        assertFalse(IsPowerTwo.isPowerTwo(5));
-        assertFalse(IsPowerTwo.isPowerTwo(15));
-        assertFalse(IsPowerTwo.isPowerTwo(1000));
+    private static Stream<Arguments> provideNumbersForPowerTwo() {
+        return Stream.of(Arguments.of(1, Boolean.TRUE), // 2^0
+            Arguments.of(2, Boolean.TRUE), // 2^1
+            Arguments.of(4, Boolean.TRUE), // 2^2
+            Arguments.of(8, Boolean.TRUE), // 2^3
+            Arguments.of(16, Boolean.TRUE), // 2^4
+            Arguments.of(32, Boolean.TRUE), // 2^5
+            Arguments.of(64, Boolean.TRUE), // 2^6
+            Arguments.of(128, Boolean.TRUE), // 2^7
+            Arguments.of(256, Boolean.TRUE), // 2^8
+            Arguments.of(1024, Boolean.TRUE), // 2^10
+            Arguments.of(0, Boolean.FALSE), // 0 is not a power of two
+            Arguments.of(-1, Boolean.FALSE), // Negative number
+            Arguments.of(-2, Boolean.FALSE), // Negative number
+            Arguments.of(-4, Boolean.FALSE), // Negative number
+            Arguments.of(3, Boolean.FALSE), // 3 is not a power of two
+            Arguments.of(5, Boolean.FALSE), // 5 is not a power of two
+            Arguments.of(6, Boolean.FALSE), // 6 is not a power of two
+            Arguments.of(15, Boolean.FALSE), // 15 is not a power of two
+            Arguments.of(1000, Boolean.FALSE), // 1000 is not a power of two
+            Arguments.of(1023, Boolean.FALSE) // 1023 is not a power of two
+        );
     }
 }

From 6fc53ecc9939d031203a05dbe6405ce51a690cf9 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:27:14 +0530
Subject: [PATCH 0644/1338] Add `IPv6Converter` algorithm (#5783)

---
 DIRECTORY.md                                  |  2 +
 .../conversions/IPv6Converter.java            | 98 +++++++++++++++++++
 .../conversions/IPv6ConverterTest.java        | 64 ++++++++++++
 3 files changed, 164 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/IPv6Converter.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/IPv6ConverterTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index fa9c26535c9b..31f46916e2b3 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -100,6 +100,7 @@
             * [IntegerToEnglish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java)
             * [IntegerToRoman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java)
             * [IPConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IPConverter.java)
+            * [IPv6Converter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IPv6Converter.java)
             * [MorseCodeConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/MorseCodeConverter.java)
             * [OctalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToBinary.java)
             * [OctalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java)
@@ -784,6 +785,7 @@
             * [IntegerToEnglishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java)
             * [IntegerToRomanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java)
             * [IPConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IPConverterTest.java)
+            * [IPv6ConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IPv6ConverterTest.java)
             * [MorseCodeConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/MorseCodeConverterTest.java)
             * [OctalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java)
             * [OctalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java)
diff --git a/src/main/java/com/thealgorithms/conversions/IPv6Converter.java b/src/main/java/com/thealgorithms/conversions/IPv6Converter.java
new file mode 100644
index 000000000000..d42ffd027514
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/IPv6Converter.java
@@ -0,0 +1,98 @@
+package com.thealgorithms.conversions;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.Arrays;
+
+/**
+ * A utility class for converting between IPv6 and IPv4 addresses.
+ *
+ * - Converts IPv4 to IPv6-mapped IPv6 address.
+ * - Extracts IPv4 address from IPv6-mapped IPv6.
+ * - Handles exceptions for invalid inputs.
+ *
+ * @author Hardvan
+ */
+public final class IPv6Converter {
+    private IPv6Converter() {
+    }
+
+    /**
+     * Converts an IPv4 address (e.g., "192.0.2.128") to an IPv6-mapped IPv6 address.
+     * Example: IPv4 "192.0.2.128" -> IPv6 "::ffff:192.0.2.128"
+     *
+     * @param ipv4Address The IPv4 address in string format.
+     * @return The corresponding IPv6-mapped IPv6 address.
+     * @throws UnknownHostException If the IPv4 address is invalid.
+     * @throws IllegalArgumentException If the IPv6 address is not a mapped IPv4 address.
+     */
+    public static String ipv4ToIpv6(String ipv4Address) throws UnknownHostException {
+        if (ipv4Address == null || ipv4Address.isEmpty()) {
+            throw new UnknownHostException("IPv4 address is empty.");
+        }
+
+        InetAddress ipv4 = InetAddress.getByName(ipv4Address);
+        byte[] ipv4Bytes = ipv4.getAddress();
+
+        // Create IPv6-mapped IPv6 address (starts with ::ffff:)
+        byte[] ipv6Bytes = new byte[16];
+        ipv6Bytes[10] = (byte) 0xff;
+        ipv6Bytes[11] = (byte) 0xff;
+        System.arraycopy(ipv4Bytes, 0, ipv6Bytes, 12, 4);
+
+        // Manually format to "::ffff:x.x.x.x" format
+        StringBuilder ipv6String = new StringBuilder("::ffff:");
+        for (int i = 12; i < 16; i++) {
+            ipv6String.append(ipv6Bytes[i] & 0xFF);
+            if (i < 15) {
+                ipv6String.append('.');
+            }
+        }
+        return ipv6String.toString();
+    }
+
+    /**
+     * Extracts the IPv4 address from an IPv6-mapped IPv6 address.
+     * Example: IPv6 "::ffff:192.0.2.128" -> IPv4 "192.0.2.128"
+     *
+     * @param ipv6Address The IPv6 address in string format.
+     * @return The extracted IPv4 address.
+     * @throws UnknownHostException If the IPv6 address is invalid or not a mapped IPv4 address.
+     */
+    public static String ipv6ToIpv4(String ipv6Address) throws UnknownHostException {
+        InetAddress ipv6 = InetAddress.getByName(ipv6Address);
+        byte[] ipv6Bytes = ipv6.getAddress();
+
+        // Check if the address is an IPv6-mapped IPv4 address
+        if (isValidIpv6MappedIpv4(ipv6Bytes)) {
+            byte[] ipv4Bytes = Arrays.copyOfRange(ipv6Bytes, 12, 16);
+            InetAddress ipv4 = InetAddress.getByAddress(ipv4Bytes);
+            return ipv4.getHostAddress();
+        } else {
+            throw new IllegalArgumentException("Not a valid IPv6-mapped IPv4 address.");
+        }
+    }
+
+    /**
+     * Helper function to check if the given byte array represents
+     * an IPv6-mapped IPv4 address (prefix 0:0:0:0:0:ffff).
+     *
+     * @param ipv6Bytes Byte array representation of the IPv6 address.
+     * @return True if the address is IPv6-mapped IPv4, otherwise false.
+     */
+    private static boolean isValidIpv6MappedIpv4(byte[] ipv6Bytes) {
+        // IPv6-mapped IPv4 addresses are 16 bytes long, with the first 10 bytes set to 0,
+        // followed by 0xff, 0xff, and the last 4 bytes representing the IPv4 address.
+        if (ipv6Bytes.length != 16) {
+            return false;
+        }
+
+        for (int i = 0; i < 10; i++) {
+            if (ipv6Bytes[i] != 0) {
+                return false;
+            }
+        }
+
+        return ipv6Bytes[10] == (byte) 0xff && ipv6Bytes[11] == (byte) 0xff;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/IPv6ConverterTest.java b/src/test/java/com/thealgorithms/conversions/IPv6ConverterTest.java
new file mode 100644
index 000000000000..443f865ae0dc
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/IPv6ConverterTest.java
@@ -0,0 +1,64 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.net.UnknownHostException;
+import org.junit.jupiter.api.Test;
+
+public class IPv6ConverterTest {
+
+    private static final String VALID_IPV4 = "192."
+        + "0."
+        + "2."
+        + "128";
+    private static final String EXPECTED_IPV6_MAPPED = ":"
+        + ":ff"
+        + "ff"
+        + ":19"
+        + "2."
+        + "0."
+        + "2.128";
+    private static final String INVALID_IPV6_MAPPED = "2001:"
+        + "db8"
+        + ":"
+        + ":1";
+    private static final String INVALID_IPV4 = "999."
+        + "999."
+        + "999."
+        + "999";
+    private static final String INVALID_IPV6_FORMAT = "invalid:ipv6"
+        + "::address";
+    private static final String EMPTY_STRING = "";
+
+    @Test
+    public void testIpv4ToIpv6ValidInput() throws UnknownHostException {
+        String actualIpv6 = IPv6Converter.ipv4ToIpv6(VALID_IPV4);
+        assertEquals(EXPECTED_IPV6_MAPPED, actualIpv6);
+    }
+
+    @Test
+    public void testIpv6ToIpv4InvalidIPv6MappedAddress() {
+        assertThrows(IllegalArgumentException.class, () -> IPv6Converter.ipv6ToIpv4(INVALID_IPV6_MAPPED));
+    }
+
+    @Test
+    public void testIpv4ToIpv6InvalidIPv4Address() {
+        assertThrows(UnknownHostException.class, () -> IPv6Converter.ipv4ToIpv6(INVALID_IPV4));
+    }
+
+    @Test
+    public void testIpv6ToIpv4InvalidFormat() {
+        assertThrows(UnknownHostException.class, () -> IPv6Converter.ipv6ToIpv4(INVALID_IPV6_FORMAT));
+    }
+
+    @Test
+    public void testIpv4ToIpv6EmptyString() {
+        assertThrows(UnknownHostException.class, () -> IPv6Converter.ipv4ToIpv6(EMPTY_STRING));
+    }
+
+    @Test
+    public void testIpv6ToIpv4EmptyString() {
+        assertThrows(IllegalArgumentException.class, () -> IPv6Converter.ipv6ToIpv4(EMPTY_STRING));
+    }
+}

From 2ec4a1f5327ad12fc1b99648017b0f6ee9523e5c Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:31:22 +0530
Subject: [PATCH 0645/1338] Enhance docs, add more tests in
 `NumberAppearingOddTimes` (#5857)

---
 .../NumberAppearingOddTimes.java              | 28 +++++++++--
 .../NumberAppearingOddTimesTest.java          | 48 ++++++++++++++-----
 2 files changed, 61 insertions(+), 15 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java b/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java
index ce4e1d88da6e..bd4868d4dbd5 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java
@@ -1,21 +1,41 @@
 package com.thealgorithms.bitmanipulation;
 
 /**
- * Find the Number Appearing Odd Times in an array
+ * This class provides a method to find the element that appears an
+ * odd number of times in an array. All other elements in the array
+ * must appear an even number of times for the logic to work.
+ *
+ * The solution uses the XOR operation, which has the following properties:
+ * - a ^ a = 0 (XOR-ing the same numbers cancels them out)
+ * - a ^ 0 = a
+ * - XOR is commutative and associative.
+ *
+ * Time Complexity: O(n), where n is the size of the array.
+ * Space Complexity: O(1), as no extra space is used.
+ *
+ * Usage Example:
+ * int result = NumberAppearingOddTimes.findOddOccurrence(new int[]{1, 2, 1, 2, 3});
+ * // result will be 3
+ *
  * @author Lakshyajeet Singh Goyal (https://github.com/DarkMatter-999)
  */
 
 public final class NumberAppearingOddTimes {
     private NumberAppearingOddTimes() {
     }
+
+    /**
+     * Finds the element in the array that appears an odd number of times.
+     *
+     * @param arr the input array containing integers, where all elements
+     *            except one appear an even number of times.
+     * @return the integer that appears an odd number of times.
+     */
     public static int findOddOccurrence(int[] arr) {
         int result = 0;
-
-        // XOR all elements in the array
         for (int num : arr) {
             result ^= num;
         }
-
         return result;
     }
 }
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java b/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java
index d10b0f67b806..83d458319f3b 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java
@@ -2,22 +2,48 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class NumberAppearingOddTimesTest {
 
-    @Test
-    void testFindOddOccurrence() {
-        int[] arr1 = {5, 6, 7, 8};
-        assertEquals(12, NumberAppearingOddTimes.findOddOccurrence(arr1));
+    /**
+     * Parameterized test for findOddOccurrence method. Tests multiple
+     * input arrays and their expected results.
+     */
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testFindOddOccurrence(int[] input, int expected) {
+        assertEquals(expected, NumberAppearingOddTimes.findOddOccurrence(input));
+    }
+
+    /**
+     * Provides test cases for the parameterized test.
+     * Each test case consists of an input array and the expected result.
+     */
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            // Single element appearing odd times (basic case)
+            Arguments.of(new int[] {5, 6, 7, 8, 6, 7, 5}, 8),
+
+            // More complex case with multiple pairs
+            Arguments.of(new int[] {2, 3, 5, 4, 5, 2, 4, 3, 5, 2, 4, 4, 2}, 5),
+
+            // Case with only one element appearing once
+            Arguments.of(new int[] {10, 10, 20, 20, 30}, 30),
+
+            // Negative numbers with an odd occurrence
+            Arguments.of(new int[] {-5, -5, -3, -3, -7, -7, -7}, -7),
 
-        int[] arr2 = {2, 3, 5, 4, 5, 2, 4, 3, 5, 2, 4, 4, 2};
-        assertEquals(5, NumberAppearingOddTimes.findOddOccurrence(arr2));
+            // All elements cancel out to 0 (even occurrences of all elements)
+            Arguments.of(new int[] {1, 2, 1, 2}, 0),
 
-        int[] arr3 = {10, 10, 20, 20, 30};
-        assertEquals(30, NumberAppearingOddTimes.findOddOccurrence(arr3));
+            // Array with a single element (trivial case)
+            Arguments.of(new int[] {42}, 42),
 
-        int[] arr4 = {-5, -5, -3, -3, -7, -7, -7};
-        assertEquals(-7, NumberAppearingOddTimes.findOddOccurrence(arr4));
+            // Large array with repeated patterns
+            Arguments.of(new int[] {1, 1, 2, 2, 3, 3, 3, 4, 4}, 3));
     }
 }

From b0cef5b571965aed5410a61531ddf1e1cb5c2608 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:35:22 +0530
Subject: [PATCH 0646/1338] Enhance docs, add more tests in
 `NumbersDifferentSigns` (#5858)

---
 .../NumbersDifferentSigns.java                | 19 +++++++-
 .../NumbersDifferentSignsTest.java            | 46 ++++++++++++-------
 2 files changed, 47 insertions(+), 18 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java b/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java
index 8e0946f0eb23..a2da37aa81ee 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java
@@ -1,14 +1,29 @@
 package com.thealgorithms.bitmanipulation;
 
 /**
- * Numbers Different Signs
+ * This class provides a method to determine whether two integers have
+ * different signs. It utilizes the XOR operation on the two numbers:
+ *
+ * - If two numbers have different signs, their most significant bits
+ *   (sign bits) will differ, resulting in a negative XOR result.
+ * - If two numbers have the same sign, the XOR result will be non-negative.
+ *
+ * Time Complexity: O(1) - Constant time operation.
+ * Space Complexity: O(1) - No extra space used.
+ *
  * @author Bama Charan Chhandogi
  */
-
 public final class NumbersDifferentSigns {
     private NumbersDifferentSigns() {
     }
 
+    /**
+     * Determines if two integers have different signs using bitwise XOR.
+     *
+     * @param num1 the first integer
+     * @param num2 the second integer
+     * @return true if the two numbers have different signs, false otherwise
+     */
     public static boolean differentSigns(int num1, int num2) {
         return (num1 ^ num2) < 0;
     }
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java
index f54070d39cdd..33e5ae048814 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java
@@ -3,30 +3,44 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
 /**
- * test Cases of Numbers Different Signs
+ * Parameterized tests for NumbersDifferentSigns class, which checks
+ * if two integers have different signs using bitwise XOR.
+ *
  * @author Bama Charan Chhandogi
  */
 class NumbersDifferentSignsTest {
 
-    @Test
-    void testDifferentSignsPositiveNegative() {
-        assertTrue(NumbersDifferentSigns.differentSigns(2, -1));
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testDifferentSigns(int num1, int num2, boolean expected) {
+        if (expected) {
+            assertTrue(NumbersDifferentSigns.differentSigns(num1, num2));
+        } else {
+            assertFalse(NumbersDifferentSigns.differentSigns(num1, num2));
+        }
     }
 
-    @Test
-    void testDifferentSignsNegativePositive() {
-        assertTrue(NumbersDifferentSigns.differentSigns(-3, 7));
-    }
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            // Different signs (positive and negative)
+            Arguments.of(2, -1, Boolean.TRUE), Arguments.of(-3, 7, Boolean.TRUE),
 
-    @Test
-    void testSameSignsPositive() {
-        assertFalse(NumbersDifferentSigns.differentSigns(10, 20));
-    }
+            // Same signs (both positive)
+            Arguments.of(10, 20, Boolean.FALSE), Arguments.of(0, 5, Boolean.FALSE), // 0 is considered non-negative
+
+            // Same signs (both negative)
+            Arguments.of(-5, -8, Boolean.FALSE),
+
+            // Edge case: Large positive and negative values
+            Arguments.of(Integer.MAX_VALUE, Integer.MIN_VALUE, Boolean.TRUE),
 
-    @Test
-    void testSameSignsNegative() {
-        assertFalse(NumbersDifferentSigns.differentSigns(-5, -8));
+            // Edge case: Same number (positive and negative)
+            Arguments.of(-42, -42, Boolean.FALSE), Arguments.of(42, 42, Boolean.FALSE));
     }
 }

From 647a82a997100952d635b617f1398f0fab08605b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:40:08 +0530
Subject: [PATCH 0647/1338] Enhance docs, remove main, add tests in
 `ReverseStack` (#6018)

---
 DIRECTORY.md                                  |  1 +
 .../datastructures/stacks/ReverseStack.java   | 83 ++++++++++---------
 .../stacks/ReverseStackTest.java              | 70 ++++++++++++++++
 3 files changed, 116 insertions(+), 38 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 31f46916e2b3..b7e9e3b87518 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -871,6 +871,7 @@
               * [TokenBucketTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/TokenBucketTest.java)
             * stacks
               * [NodeStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java)
+              * [ReverseStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java)
               * [StackArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java)
               * [StackArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java)
               * [StackOfLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java b/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
index 84e9df96e0d9..e9de14b53302 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
@@ -1,10 +1,25 @@
 package com.thealgorithms.datastructures.stacks;
 
-import java.util.Scanner;
 import java.util.Stack;
 
 /**
- * Reversal of a stack using recursion.
+ * Provides methods to reverse a stack using recursion.
+ *
+ * <p>This class includes methods to reverse the order of elements in a stack
+ * without using additional data structures. Elements are inserted at the bottom
+ * of the stack to achieve the reverse order.
+ *
+ * <p>Example usage:
+ * <pre>
+ *     Stack<Integer> stack = new Stack<>();
+ *     stack.push(1);
+ *     stack.push(2);
+ *     stack.push(3);
+ *     ReverseStack.reverseStack(stack);
+ * </pre>
+ * After calling {@code reverseStack(stack)}, the stack's order is reversed.
+ *
+ * <p>This class is final and has a private constructor to prevent instantiation.
  *
  * @author Ishika Agarwal, 2021
  */
@@ -12,56 +27,48 @@ public final class ReverseStack {
     private ReverseStack() {
     }
 
-    public static void main(String[] args) {
-        try (Scanner sc = new Scanner(System.in)) {
-            System.out.println("Enter the number of elements you wish to insert in the stack");
-            int n = sc.nextInt();
-            int i;
-            Stack<Integer> stack = new Stack<Integer>();
-            System.out.println("Enter the stack elements");
-            for (i = 0; i < n; i++) {
-                stack.push(sc.nextInt());
-            }
-            reverseStack(stack);
-            System.out.println("The reversed stack is:");
-            while (!stack.isEmpty()) {
-                System.out.print(stack.peek() + ",");
-                stack.pop();
-            }
-        }
-    }
-
-    private static void reverseStack(Stack<Integer> stack) {
+    /**
+     * Reverses the order of elements in the given stack using recursion.
+     * Steps:
+     * 1. Check if the stack is empty. If so, return.
+     * 2. Pop the top element from the stack.
+     * 3. Recursively reverse the remaining stack.
+     * 4. Insert the originally popped element at the bottom of the reversed stack.
+     *
+     * @param stack the stack to reverse; should not be null
+     */
+    public static void reverseStack(Stack<Integer> stack) {
         if (stack.isEmpty()) {
             return;
         }
 
-        // Store the topmost element
-        int element = stack.peek();
-        // Remove the topmost element
-        stack.pop();
-
-        // Reverse the stack for the leftover elements
+        int element = stack.pop();
         reverseStack(stack);
-
-        // Insert the topmost element to the bottom of the stack
         insertAtBottom(stack, element);
     }
 
+    /**
+     * Inserts the specified element at the bottom of the stack.
+     *
+     * <p>This method is a helper for {@link #reverseStack(Stack)}.
+     *
+     * Steps:
+     * 1. If the stack is empty, push the element and return.
+     * 2. Remove the top element from the stack.
+     * 3. Recursively insert the new element at the bottom of the stack.
+     * 4. Push the removed element back onto the stack.
+     *
+     * @param stack the stack in which to insert the element; should not be null
+     * @param element the element to insert at the bottom of the stack
+     */
     private static void insertAtBottom(Stack<Integer> stack, int element) {
         if (stack.isEmpty()) {
-            // When stack is empty, insert the element so it will be present at
-            // the bottom of the stack
             stack.push(element);
             return;
         }
 
-        int ele = stack.peek();
-        // Keep popping elements till stack becomes empty. Push the elements
-        // once the topmost element has moved to the bottom of the stack.
-        stack.pop();
+        int topElement = stack.pop();
         insertAtBottom(stack, element);
-
-        stack.push(ele);
+        stack.push(topElement);
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java
new file mode 100644
index 000000000000..2e2bc5adae3a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java
@@ -0,0 +1,70 @@
+package com.thealgorithms.datastructures.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Stack;
+import org.junit.jupiter.api.Test;
+
+class ReverseStackTest {
+
+    @Test
+    void testReverseEmptyStack() {
+        Stack<Integer> stack = new Stack<>();
+        ReverseStack.reverseStack(stack);
+        assertTrue(stack.isEmpty(), "Reversing an empty stack should result in an empty stack.");
+    }
+
+    @Test
+    void testReverseSingleElementStack() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(1);
+        ReverseStack.reverseStack(stack);
+        assertEquals(1, stack.peek(), "Reversing a single-element stack should have the same element on top.");
+    }
+
+    @Test
+    void testReverseTwoElementStack() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(1);
+        stack.push(2);
+        ReverseStack.reverseStack(stack);
+
+        assertEquals(1, stack.pop(), "After reversal, the stack's top element should be the first inserted element.");
+        assertEquals(2, stack.pop(), "After reversal, the stack's next element should be the second inserted element.");
+    }
+
+    @Test
+    void testReverseMultipleElementsStack() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+        stack.push(4);
+
+        ReverseStack.reverseStack(stack);
+
+        assertEquals(1, stack.pop(), "Stack order after reversal should match the initial push order.");
+        assertEquals(2, stack.pop());
+        assertEquals(3, stack.pop());
+        assertEquals(4, stack.pop());
+    }
+
+    @Test
+    void testReverseStackAndVerifySize() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(10);
+        stack.push(20);
+        stack.push(30);
+        stack.push(40);
+        int originalSize = stack.size();
+
+        ReverseStack.reverseStack(stack);
+
+        assertEquals(originalSize, stack.size(), "Stack size should remain unchanged after reversal.");
+        assertEquals(10, stack.pop(), "Reversal should place the first inserted element on top.");
+        assertEquals(20, stack.pop());
+        assertEquals(30, stack.pop());
+        assertEquals(40, stack.pop());
+    }
+}

From ef7f2e97e38367a58981d294b29f59981553c988 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:44:20 +0530
Subject: [PATCH 0648/1338] Enhance docs, add more tests in
 `SingleBitOperations` (#5860)

---
 .../bitmanipulation/SingleBitOperations.java  | 48 +++++++++++--
 .../SingleBitOperationsTest.java              | 69 +++++++++++++------
 2 files changed, 88 insertions(+), 29 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java b/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java
index b41aeca19af6..624a4e2b858a 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java
@@ -1,34 +1,68 @@
 package com.thealgorithms.bitmanipulation;
 
-/*
+/**
+ * A utility class for performing single-bit operations on integers.
+ * These operations include flipping, setting, clearing, and getting
+ * individual bits at specified positions.
+ *
+ * Bit positions are zero-indexed (i.e., the least significant bit is at position 0).
+ * These methods leverage bitwise operations for optimal performance.
+ *
+ * Examples:
+ * - `flipBit(3, 1)` flips the bit at index 1 in binary `11` (result: `1`).
+ * - `setBit(4, 0)` sets the bit at index 0 in `100` (result: `101` or 5).
+ * - `clearBit(7, 1)` clears the bit at index 1 in `111` (result: `101` or 5).
+ * - `getBit(6, 0)` checks if the least significant bit is set (result: `0`).
+ *
+ * Time Complexity: O(1) for all operations.
+ *
  * Author: lukasb1b (https://github.com/lukasb1b)
  */
-
 public final class SingleBitOperations {
     private SingleBitOperations() {
     }
+
     /**
-     * Flip the bit at position 'bit' in 'num'
+     * Flips (toggles) the bit at the specified position.
+     *
+     * @param num the input number
+     * @param bit the position of the bit to flip (0-indexed)
+     * @return the new number after flipping the specified bit
      */
     public static int flipBit(final int num, final int bit) {
         return num ^ (1 << bit);
     }
+
     /**
-     * Set the bit at position 'bit' to 1 in the 'num' variable
+     * Sets the bit at the specified position to 1.
+     *
+     * @param num the input number
+     * @param bit the position of the bit to set (0-indexed)
+     * @return the new number after setting the specified bit to 1
      */
     public static int setBit(final int num, final int bit) {
         return num | (1 << bit);
     }
+
     /**
-     * Clears the bit located at 'bit' from 'num'
+     * Clears the bit at the specified position (sets it to 0).
+     *
+     * @param num the input number
+     * @param bit the position of the bit to clear (0-indexed)
+     * @return the new number after clearing the specified bit
      */
     public static int clearBit(final int num, final int bit) {
         return num & ~(1 << bit);
     }
+
     /**
-     * Get the bit located at 'bit' from 'num'
+     * Gets the bit value (0 or 1) at the specified position.
+     *
+     * @param num the input number
+     * @param bit the position of the bit to retrieve (0-indexed)
+     * @return 1 if the bit is set, 0 otherwise
      */
     public static int getBit(final int num, final int bit) {
-        return ((num >> bit) & 1);
+        return (num >> bit) & 1;
     }
 }
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java
index 9cac8d670a4a..6c447ec9805e 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java
@@ -2,35 +2,60 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
-public class SingleBitOperationsTest {
+class SingleBitOperationsTest {
 
-    @Test
-    public void flipBitTest() {
-        assertEquals(1, SingleBitOperations.flipBit(3, 1));
-        assertEquals(11, SingleBitOperations.flipBit(3, 3));
+    @ParameterizedTest
+    @MethodSource("provideFlipBitTestCases")
+    void testFlipBit(int input, int bit, int expected) {
+        assertEquals(expected, SingleBitOperations.flipBit(input, bit));
     }
 
-    @Test
-    public void setBitTest() {
-        assertEquals(5, SingleBitOperations.setBit(4, 0));
-        assertEquals(4, SingleBitOperations.setBit(4, 2));
-        assertEquals(5, SingleBitOperations.setBit(5, 0));
-        assertEquals(14, SingleBitOperations.setBit(10, 2));
-        assertEquals(15, SingleBitOperations.setBit(15, 3));
-        assertEquals(2, SingleBitOperations.setBit(0, 1));
+    private static Stream<Arguments> provideFlipBitTestCases() {
+        return Stream.of(Arguments.of(3, 1, 1), // Binary: 11 -> 01
+            Arguments.of(3, 3, 11) // Binary: 11 -> 1011
+        );
     }
 
-    @Test
-    public void clearBitTest() {
-        assertEquals(5, SingleBitOperations.clearBit(7, 1));
-        assertEquals(5, SingleBitOperations.clearBit(5, 1));
+    @ParameterizedTest
+    @MethodSource("provideSetBitTestCases")
+    void testSetBit(int input, int bit, int expected) {
+        assertEquals(expected, SingleBitOperations.setBit(input, bit));
     }
 
-    @Test
-    public void getBitTest() {
-        assertEquals(0, SingleBitOperations.getBit(6, 0));
-        assertEquals(1, SingleBitOperations.getBit(7, 1));
+    private static Stream<Arguments> provideSetBitTestCases() {
+        return Stream.of(Arguments.of(4, 0, 5), // 100 -> 101
+            Arguments.of(4, 2, 4), // 100 -> 100 (bit already set)
+            Arguments.of(0, 1, 2), // 00 -> 10
+            Arguments.of(10, 2, 14) // 1010 -> 1110
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideClearBitTestCases")
+    void testClearBit(int input, int bit, int expected) {
+        assertEquals(expected, SingleBitOperations.clearBit(input, bit));
+    }
+
+    private static Stream<Arguments> provideClearBitTestCases() {
+        return Stream.of(Arguments.of(7, 1, 5), // 111 -> 101
+            Arguments.of(5, 1, 5) // 101 -> 101 (bit already cleared)
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideGetBitTestCases")
+    void testGetBit(int input, int bit, int expected) {
+        assertEquals(expected, SingleBitOperations.getBit(input, bit));
+    }
+
+    private static Stream<Arguments> provideGetBitTestCases() {
+        return Stream.of(Arguments.of(6, 0, 0), // 110 -> Bit 0: 0
+            Arguments.of(7, 1, 1) // 111 -> Bit 1: 1
+        );
     }
 }

From fb85a4884fd2e70b02cb753437cf80dbb453f37d Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:48:17 +0530
Subject: [PATCH 0649/1338] Enhance docs, add more tests in `TwosComplement`
 (#5862)

---
 .../bitmanipulation/TwosComplement.java       | 55 +++++++++++++------
 .../bitmanipulation/TwosComplementTest.java   | 38 ++++++++-----
 2 files changed, 62 insertions(+), 31 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java b/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java
index 0bc200722943..9b8cecd791a6 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java
@@ -1,41 +1,62 @@
 package com.thealgorithms.bitmanipulation;
 
 /**
- * @wikipedia - https://en.wikipedia.org/wiki/Two%27s_complement
- *            This Algorithm was first suggested by Jon Von Neumann
- * @author - https://github.com/Monk-AbhinayVerma
- * @return the two's complement of any binary number
+ * This class provides a method to compute the Two's Complement of a given binary number.
+ *
+ * <p>In two's complement representation, a binary number's negative value is obtained
+ * by taking the one's complement (inverting all bits) and then adding 1 to the result.
+ * This method handles both small and large binary strings and ensures the output is
+ * correct for all binary inputs, including edge cases like all zeroes and all ones.
+ *
+ * <p>For more information on Two's Complement:
+ * @see <a href="https://en.wikipedia.org/wiki/Two%27s_complement">Wikipedia - Two's Complement</a>
+ *
+ * <p>Algorithm originally suggested by Jon von Neumann.
+ *
+ * @author Abhinay Verma (https://github.com/Monk-AbhinayVerma)
  */
 public final class TwosComplement {
     private TwosComplement() {
     }
 
-    // Function to get the 2's complement of a binary number
+    /**
+     * Computes the Two's Complement of the given binary string.
+     * Steps:
+     * 1. Compute the One's Complement (invert all bits).
+     * 2. Add 1 to the One's Complement to get the Two's Complement.
+     * 3. Iterate from the rightmost bit to the left, adding 1 and carrying over as needed.
+     * 4. If a carry is still present after the leftmost bit, prepend '1' to handle overflow.
+     *
+     * @param binary The binary number as a string (only '0' and '1' characters allowed).
+     * @return The two's complement of the input binary string as a new binary string.
+     * @throws IllegalArgumentException If the input contains non-binary characters.
+     */
     public static String twosComplement(String binary) {
+        if (!binary.matches("[01]+")) {
+            throw new IllegalArgumentException("Input must contain only '0' and '1'.");
+        }
+
         StringBuilder onesComplement = new StringBuilder();
-        // Step 1: Find the 1's complement (invert the bits)
-        for (int i = 0; i < binary.length(); i++) {
-            if (binary.charAt(i) == '0') {
-                onesComplement.append('1');
-            } else {
-                onesComplement.append('0');
-            }
+        for (char bit : binary.toCharArray()) {
+            onesComplement.append(bit == '0' ? '1' : '0');
         }
-        // Step 2: Add 1 to the 1's complement
+
         StringBuilder twosComplement = new StringBuilder(onesComplement);
         boolean carry = true;
-        for (int i = onesComplement.length() - 1; i >= 0; i--) {
-            if (onesComplement.charAt(i) == '1' && carry) {
+
+        for (int i = onesComplement.length() - 1; i >= 0 && carry; i--) {
+            if (onesComplement.charAt(i) == '1') {
                 twosComplement.setCharAt(i, '0');
-            } else if (onesComplement.charAt(i) == '0' && carry) {
+            } else {
                 twosComplement.setCharAt(i, '1');
                 carry = false;
             }
         }
-        // If there is still a carry, append '1' at the beginning
+
         if (carry) {
             twosComplement.insert(0, '1');
         }
+
         return twosComplement.toString();
     }
 }
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java b/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java
index 512e94b6374e..578acc7af18c 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.bitmanipulation;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
@@ -12,7 +13,6 @@ public class TwosComplementTest {
 
     @Test
     public void testTwosComplementAllZeroes() {
-        // Test with a binary number consisting entirely of zeroes
         assertEquals("10000", TwosComplement.twosComplement("0000"));
         assertEquals("1000", TwosComplement.twosComplement("000"));
         assertEquals("100", TwosComplement.twosComplement("00"));
@@ -21,7 +21,6 @@ public void testTwosComplementAllZeroes() {
 
     @Test
     public void testTwosComplementAllOnes() {
-        // Test with a binary number consisting entirely of ones
         assertEquals("00001", TwosComplement.twosComplement("11111"));
         assertEquals("0001", TwosComplement.twosComplement("1111"));
         assertEquals("001", TwosComplement.twosComplement("111"));
@@ -30,25 +29,36 @@ public void testTwosComplementAllOnes() {
 
     @Test
     public void testTwosComplementMixedBits() {
-        // Test with binary numbers with mixed bits
-        assertEquals("1111", TwosComplement.twosComplement("0001")); // 1's complement: 1110, then add 1: 1111
-        assertEquals("1001", TwosComplement.twosComplement("0111")); // 1's complement: 1000
-        assertEquals("11001", TwosComplement.twosComplement("00111")); // 1's complement: 11000, add 1: 11001
-        assertEquals("011", TwosComplement.twosComplement("101")); // 1's complement: 010, add 1: 011
+        assertEquals("1111", TwosComplement.twosComplement("0001")); // 1 -> 1111
+        assertEquals("1001", TwosComplement.twosComplement("0111")); // 0111 -> 1001
+        assertEquals("11001", TwosComplement.twosComplement("00111")); // 00111 -> 11001
+        assertEquals("011", TwosComplement.twosComplement("101")); // 101 -> 011
     }
 
     @Test
     public void testTwosComplementSingleBit() {
-        // Test with single bit
-        assertEquals("10", TwosComplement.twosComplement("0"));
-        assertEquals("1", TwosComplement.twosComplement("1"));
+        assertEquals("10", TwosComplement.twosComplement("0")); // 0 -> 10
+        assertEquals("1", TwosComplement.twosComplement("1")); // 1 -> 1
     }
 
     @Test
     public void testTwosComplementWithLeadingZeroes() {
-        // Test with leading zeroes in the input
-        assertEquals("1111", TwosComplement.twosComplement("0001"));
-        assertEquals("101", TwosComplement.twosComplement("011"));
-        assertEquals("110", TwosComplement.twosComplement("010"));
+        assertEquals("1111", TwosComplement.twosComplement("0001")); // 0001 -> 1111
+        assertEquals("101", TwosComplement.twosComplement("011")); // 011 -> 101
+        assertEquals("110", TwosComplement.twosComplement("010")); // 010 -> 110
+    }
+
+    @Test
+    public void testInvalidBinaryInput() {
+        // Test for invalid input that contains non-binary characters.
+        assertThrows(IllegalArgumentException.class, () -> TwosComplement.twosComplement("102"));
+        assertThrows(IllegalArgumentException.class, () -> TwosComplement.twosComplement("abc"));
+        assertThrows(IllegalArgumentException.class, () -> TwosComplement.twosComplement("10a01"));
+    }
+
+    @Test
+    public void testEmptyInput() {
+        // Edge case: Empty input should result in an IllegalArgumentException.
+        assertThrows(IllegalArgumentException.class, () -> TwosComplement.twosComplement(""));
     }
 }

From 8551addbf2233420759265bea912812825ce5854 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:52:29 +0530
Subject: [PATCH 0650/1338] Add `ModuloPowerOfTwo` algorithm (#5863)

---
 DIRECTORY.md                                  |  2 +
 .../bitmanipulation/ModuloPowerOfTwo.java     | 28 ++++++++++++++
 .../bitmanipulation/ModuloPowerOfTwoTest.java | 38 +++++++++++++++++++
 3 files changed, 68 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwo.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwoTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b7e9e3b87518..b865a9bb0d4d 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -39,6 +39,7 @@
             * [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
             * [IsPowerTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java)
             * [LowestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/LowestSetBit.java)
+            * [ModuloPowerOfTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwo.java)
             * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
             * [NumberAppearingOddTimes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
@@ -731,6 +732,7 @@
             * [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
             * [IsPowerTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java)
             * [LowestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java)
+            * [ModuloPowerOfTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwoTest.java)
             * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
             * [NumberAppearingOddTimesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwo.java b/src/main/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwo.java
new file mode 100644
index 000000000000..537a046f77e4
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwo.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class provides a method to compute the remainder
+ * of a number when divided by a power of two (2^n)
+ * without using division or modulo operations.
+ *
+ * @author Hardvan
+ */
+public final class ModuloPowerOfTwo {
+    private ModuloPowerOfTwo() {
+    }
+
+    /**
+     * Computes the remainder of a given integer when divided by 2^n.
+     *
+     * @param x the input number
+     * @param n the exponent (power of two)
+     * @return the remainder of x divided by 2^n
+     */
+    public static int moduloPowerOfTwo(int x, int n) {
+        if (n <= 0) {
+            throw new IllegalArgumentException("The exponent must be positive");
+        }
+
+        return x & ((1 << n) - 1);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwoTest.java b/src/test/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwoTest.java
new file mode 100644
index 000000000000..ff7f621a64c0
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwoTest.java
@@ -0,0 +1,38 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class ModuloPowerOfTwoTest {
+
+    @ParameterizedTest
+    @CsvSource({
+        "10, 3, 2",
+        "15, 2, 3",
+        "20, 4, 4",
+        "7, 1, 1",
+        "5, 1, 1",
+        "36, 5, 4",
+    })
+    void
+    testModuloPowerOfTwo(int x, int n, int expected) {
+        assertEquals(expected, ModuloPowerOfTwo.moduloPowerOfTwo(x, n));
+    }
+
+    @ParameterizedTest
+    @CsvSource({
+        "10, 0",
+        "15, -2",
+        "20, -4",
+        "7, -1",
+        "5, -1",
+    })
+    void
+    testNegativeExponent(int x, int n) {
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> ModuloPowerOfTwo.moduloPowerOfTwo(x, n));
+        assertEquals("The exponent must be positive", exception.getMessage());
+    }
+}

From cdf509fc0614c0fe515a1162e979d683315bab2f Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 14:56:46 +0530
Subject: [PATCH 0651/1338] Add `OneBitDifference` algorithm (#5864)

---
 DIRECTORY.md                                  |  2 ++
 .../bitmanipulation/OneBitDifference.java     | 32 +++++++++++++++++++
 .../bitmanipulation/OneBitDifferenceTest.java | 15 +++++++++
 3 files changed, 49 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/OneBitDifference.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/OneBitDifferenceTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b865a9bb0d4d..8edcb19dfaf4 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -43,6 +43,7 @@
             * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
             * [NumberAppearingOddTimes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
+            * [OneBitDifference](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/OneBitDifference.java)
             * [OnesComplement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java)
             * [ParityCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ParityCheck.java)
             * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
@@ -736,6 +737,7 @@
             * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
             * [NumberAppearingOddTimesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
+            * [OneBitDifferenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/OneBitDifferenceTest.java)
             * [OnesComplementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java)
             * [ParityCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java)
             * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/OneBitDifference.java b/src/main/java/com/thealgorithms/bitmanipulation/OneBitDifference.java
new file mode 100644
index 000000000000..afec0188e299
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/OneBitDifference.java
@@ -0,0 +1,32 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class provides a method to detect if two integers
+ * differ by exactly one bit flip.
+ *
+ * Example:
+ * 1 (0001) and 2 (0010) differ by exactly one bit flip.
+ * 7 (0111) and 3 (0011) differ by exactly one bit flip.
+ *
+ * @author Hardvan
+ */
+public final class OneBitDifference {
+    private OneBitDifference() {
+    }
+
+    /**
+     * Checks if two integers differ by exactly one bit.
+     *
+     * @param x the first integer
+     * @param y the second integer
+     * @return true if x and y differ by exactly one bit, false otherwise
+     */
+    public static boolean differByOneBit(int x, int y) {
+        if (x == y) {
+            return false;
+        }
+
+        int xor = x ^ y;
+        return (xor & (xor - 1)) == 0;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/OneBitDifferenceTest.java b/src/test/java/com/thealgorithms/bitmanipulation/OneBitDifferenceTest.java
new file mode 100644
index 000000000000..06b8d32d3406
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/OneBitDifferenceTest.java
@@ -0,0 +1,15 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class OneBitDifferenceTest {
+
+    @ParameterizedTest
+    @CsvSource({"7, 5, true", "3, 2, true", "10, 8, true", "15, 15, false", "4, 1, false"})
+    void testDifferByOneBit(int x, int y, boolean expected) {
+        assertEquals(expected, OneBitDifference.differByOneBit(x, y));
+    }
+}

From d57299789480f9f709e477d406b39e1e61e31372 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 15:00:42 +0530
Subject: [PATCH 0652/1338] Add KthElementFinder algorithm (#5836)

---
 DIRECTORY.md                                  |  2 +
 .../heaps/KthElementFinder.java               | 60 +++++++++++++++++++
 .../heaps/KthElementFinderTest.java           | 19 ++++++
 3 files changed, 81 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/heaps/KthElementFinder.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 8edcb19dfaf4..a5d3a1a267a0 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -174,6 +174,7 @@
               * [GenericHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java)
               * [Heap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/Heap.java)
               * [HeapElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java)
+              * [KthElementFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/KthElementFinder.java)
               * [LeftistHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java)
               * [MaxHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java)
               * [MinHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java)
@@ -848,6 +849,7 @@
             * heaps
               * [FibonacciHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
               * [GenericHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java)
+              * [KthElementFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java)
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
               * [MinPriorityQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java)
             * lists
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/KthElementFinder.java b/src/main/java/com/thealgorithms/datastructures/heaps/KthElementFinder.java
new file mode 100644
index 000000000000..7ad92e8ba3c1
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/KthElementFinder.java
@@ -0,0 +1,60 @@
+
+package com.thealgorithms.datastructures.heaps;
+
+import java.util.PriorityQueue;
+
+/**
+ * This class provides methods to find the Kth largest or Kth smallest element
+ * in an array using heaps. It leverages a min-heap to find the Kth largest element
+ * and a max-heap to find the Kth smallest element efficiently.
+ *
+ * @author Hardvan
+ */
+public final class KthElementFinder {
+    private KthElementFinder() {
+    }
+
+    /**
+     * Finds the Kth largest element in the given array.
+     * Uses a min-heap of size K to track the largest K elements.
+     *
+     * Time Complexity: O(n * log(k)), where n is the size of the input array.
+     * Space Complexity: O(k), as we maintain a heap of size K.
+     *
+     * @param nums the input array of integers
+     * @param k the desired Kth position (1-indexed, i.e., 1 means the largest element)
+     * @return the Kth largest element in the array
+     */
+    public static int findKthLargest(int[] nums, int k) {
+        PriorityQueue<Integer> minHeap = new PriorityQueue<>(k);
+        for (int num : nums) {
+            minHeap.offer(num);
+            if (minHeap.size() > k) {
+                minHeap.poll();
+            }
+        }
+        return minHeap.peek();
+    }
+
+    /**
+     * Finds the Kth smallest element in the given array.
+     * Uses a max-heap of size K to track the smallest K elements.
+     *
+     * Time Complexity: O(n * log(k)), where n is the size of the input array.
+     * Space Complexity: O(k), as we maintain a heap of size K.
+     *
+     * @param nums the input array of integers
+     * @param k the desired Kth position (1-indexed, i.e., 1 means the smallest element)
+     * @return the Kth smallest element in the array
+     */
+    public static int findKthSmallest(int[] nums, int k) {
+        PriorityQueue<Integer> maxHeap = new PriorityQueue<>((a, b) -> b - a);
+        for (int num : nums) {
+            maxHeap.offer(num);
+            if (maxHeap.size() > k) {
+                maxHeap.poll();
+            }
+        }
+        return maxHeap.peek();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java
new file mode 100644
index 000000000000..7b92a57eaa77
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java
@@ -0,0 +1,19 @@
+package com.thealgorithms.datastructures.heaps;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class KthElementFinderTest {
+    @Test
+    public void testFindKthLargest() {
+        int[] nums = {3, 2, 1, 5, 6, 4};
+        assertEquals(5, KthElementFinder.findKthLargest(nums, 2));
+    }
+
+    @Test
+    public void testFindKthSmallest() {
+        int[] nums = {7, 10, 4, 3, 20, 15};
+        assertEquals(7, KthElementFinder.findKthSmallest(nums, 3));
+    }
+}

From 5d428d08a2e71b6b16754ede5ab0af630836affc Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 15:05:23 +0530
Subject: [PATCH 0653/1338] Add MedianFinder algorithm (#5837)

---
 DIRECTORY.md                                  |  2 +
 .../datastructures/heaps/MedianFinder.java    | 59 +++++++++++++++++++
 .../heaps/MedianFinderTest.java               | 17 ++++++
 3 files changed, 78 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/heaps/MedianFinder.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index a5d3a1a267a0..15f91de168eb 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -177,6 +177,7 @@
               * [KthElementFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/KthElementFinder.java)
               * [LeftistHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java)
               * [MaxHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java)
+              * [MedianFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MedianFinder.java)
               * [MinHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java)
               * [MinPriorityQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java)
             * lists
@@ -851,6 +852,7 @@
               * [GenericHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java)
               * [KthElementFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java)
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
+              * [MedianFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java)
               * [MinPriorityQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java)
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MedianFinder.java b/src/main/java/com/thealgorithms/datastructures/heaps/MedianFinder.java
new file mode 100644
index 000000000000..4e74aaec4a10
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MedianFinder.java
@@ -0,0 +1,59 @@
+package com.thealgorithms.datastructures.heaps;
+
+import java.util.PriorityQueue;
+
+/**
+ * This class maintains the median of a dynamically changing data stream using
+ * two heaps: a max-heap and a min-heap. The max-heap stores the smaller half
+ * of the numbers, and the min-heap stores the larger half.
+ * This data structure ensures that retrieving the median is efficient.
+ *
+ * Time Complexity:
+ * - Adding a number: O(log n) due to heap insertion.
+ * - Finding the median: O(1).
+ *
+ * Space Complexity: O(n), where n is the total number of elements added.
+ *
+ * @author Hardvan
+ */
+public final class MedianFinder {
+    MedianFinder() {
+    }
+
+    private PriorityQueue<Integer> minHeap = new PriorityQueue<>();
+    private PriorityQueue<Integer> maxHeap = new PriorityQueue<>((a, b) -> b - a);
+
+    /**
+     * Adds a new number to the data stream. The number is placed in the appropriate
+     * heap to maintain the balance between the two heaps.
+     *
+     * @param num the number to be added to the data stream
+     */
+    public void addNum(int num) {
+        if (maxHeap.isEmpty() || num <= maxHeap.peek()) {
+            maxHeap.offer(num);
+        } else {
+            minHeap.offer(num);
+        }
+
+        if (maxHeap.size() > minHeap.size() + 1) {
+            minHeap.offer(maxHeap.poll());
+        } else if (minHeap.size() > maxHeap.size()) {
+            maxHeap.offer(minHeap.poll());
+        }
+    }
+
+    /**
+     * Finds the median of the numbers added so far. If the total number of elements
+     * is even, the median is the average of the two middle elements. If odd, the
+     * median is the middle element from the max-heap.
+     *
+     * @return the median of the numbers in the data stream
+     */
+    public double findMedian() {
+        if (maxHeap.size() == minHeap.size()) {
+            return (maxHeap.peek() + minHeap.peek()) / 2.0;
+        }
+        return maxHeap.peek();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java
new file mode 100644
index 000000000000..fcacb21fcfc3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java
@@ -0,0 +1,17 @@
+package com.thealgorithms.datastructures.heaps;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class MedianFinderTest {
+    @Test
+    public void testMedianMaintenance() {
+        MedianFinder mf = new MedianFinder();
+        mf.addNum(1);
+        mf.addNum(2);
+        assertEquals(1.5, mf.findMedian());
+        mf.addNum(3);
+        assertEquals(2.0, mf.findMedian());
+    }
+}

From e4ef072f83633961f682ccaf4482949bcec44262 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 15:13:56 +0530
Subject: [PATCH 0654/1338] Add `FirstDifferentBit` algorithm (#5866)

---
 DIRECTORY.md                                  |  2 ++
 .../bitmanipulation/FirstDifferentBit.java    | 33 +++++++++++++++++++
 .../FirstDifferentBitTest.java                | 15 +++++++++
 3 files changed, 50 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/FirstDifferentBit.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/FirstDifferentBitTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 15f91de168eb..10922d761952 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -31,6 +31,7 @@
             * [CountLeadingZeros](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java)
             * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
             * [FindNthBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/FindNthBit.java)
+            * [FirstDifferentBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/FirstDifferentBit.java)
             * [GrayCodeConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java)
             * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java)
             * [HigherLowerPowerOfTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java)
@@ -727,6 +728,7 @@
             * [CountLeadingZerosTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java)
             * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
             * [FindNthBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/FindNthBitTest.java)
+            * [FirstDifferentBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/FirstDifferentBitTest.java)
             * [GrayCodeConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java)
             * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java)
             * [HigherLowerPowerOfTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/FirstDifferentBit.java b/src/main/java/com/thealgorithms/bitmanipulation/FirstDifferentBit.java
new file mode 100644
index 000000000000..9a761c572e2c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/FirstDifferentBit.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class provides a method to find the first differing bit
+ * between two integers.
+ *
+ * Example:
+ *  x = 10 (1010 in binary)
+ *  y = 12 (1100 in binary)
+ *  The first differing bit is at index 1 (0-based)
+ *  So, the output will be 1
+ *
+ * @author Hardvan
+ */
+public final class FirstDifferentBit {
+    private FirstDifferentBit() {
+    }
+
+    /**
+     * Identifies the index of the first differing bit between two integers.
+     * Steps:
+     * 1. XOR the two integers to get the differing bits
+     * 2. Find the index of the first set bit in XOR result
+     *
+     * @param x the first integer
+     * @param y the second integer
+     * @return the index of the first differing bit (0-based)
+     */
+    public static int firstDifferentBit(int x, int y) {
+        int diff = x ^ y;
+        return Integer.numberOfTrailingZeros(diff);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/FirstDifferentBitTest.java b/src/test/java/com/thealgorithms/bitmanipulation/FirstDifferentBitTest.java
new file mode 100644
index 000000000000..ae7bad9a666a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/FirstDifferentBitTest.java
@@ -0,0 +1,15 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class FirstDifferentBitTest {
+
+    @ParameterizedTest
+    @CsvSource({"10, 8, 1", "7, 5, 1", "15, 14, 0", "1, 2, 0"})
+    void testFirstDifferentBit(int x, int y, int expected) {
+        assertEquals(expected, FirstDifferentBit.firstDifferentBit(x, y));
+    }
+}

From 70adf6f223c392b50012d7a0098521870ca55691 Mon Sep 17 00:00:00 2001
From: Saahil Mahato <115351000+saahil-mahato@users.noreply.github.com>
Date: Sat, 26 Oct 2024 15:34:10 +0545
Subject: [PATCH 0655/1338] Add midpoint ellipse algorithm (#5870)

---
 .../geometry/MidpointEllipse.java             | 131 ++++++++++++++++++
 .../geometry/MidpointEllipseTest.java         |  99 +++++++++++++
 2 files changed, 230 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/geometry/MidpointEllipse.java
 create mode 100644 src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java

diff --git a/src/main/java/com/thealgorithms/geometry/MidpointEllipse.java b/src/main/java/com/thealgorithms/geometry/MidpointEllipse.java
new file mode 100644
index 000000000000..fbd53c679960
--- /dev/null
+++ b/src/main/java/com/thealgorithms/geometry/MidpointEllipse.java
@@ -0,0 +1,131 @@
+package com.thealgorithms.geometry;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * The MidpointEllipse class implements the Midpoint Ellipse Drawing Algorithm.
+ * This algorithm efficiently computes the points on an ellipse by dividing it into two regions
+ * and using decision parameters to determine the next point to plot.
+ */
+public final class MidpointEllipse {
+
+    private MidpointEllipse() {
+        // Private constructor to prevent instantiation
+    }
+
+    /**
+     * Draws an ellipse using the Midpoint Ellipse Algorithm.
+     *
+     * @param centerX the x-coordinate of the center of the ellipse
+     * @param centerY the y-coordinate of the center of the ellipse
+     * @param a the length of the semi-major axis (horizontal radius)
+     * @param b the length of the semi-minor axis (vertical radius)
+     * @return a list of points (represented as int arrays) that form the ellipse
+     */
+    public static List<int[]> drawEllipse(int centerX, int centerY, int a, int b) {
+        List<int[]> points = new ArrayList<>();
+
+        // Handle degenerate cases with early returns
+        if (a == 0 && b == 0) {
+            points.add(new int[] {centerX, centerY}); // Only the center point
+            return points;
+        }
+
+        if (a == 0) {
+            // Semi-major axis is zero, create a vertical line
+            for (int y = centerY - b; y <= centerY + b; y++) {
+                points.add(new int[] {centerX, y});
+            }
+            return points; // Early return
+        }
+
+        if (b == 0) {
+            // Semi-minor axis is zero, create a horizontal line
+            for (int x = centerX - a; x <= centerX + a; x++) {
+                points.add(new int[] {x, centerY});
+            }
+            return points; // Early return
+        }
+
+        // Normal case: Non-degenerate ellipse
+        computeEllipsePoints(points, centerX, centerY, a, b);
+
+        return points; // Return all calculated points of the ellipse
+    }
+
+    /**
+     * Computes points of a non-degenerate ellipse using the Midpoint Ellipse Algorithm.
+     *
+     * @param points    the list to which points will be added
+     * @param centerX  the x-coordinate of the center of the ellipse
+     * @param centerY  the y-coordinate of the center of the ellipse
+     * @param a        the length of the semi-major axis (horizontal radius)
+     * @param b        the length of the semi-minor axis (vertical radius)
+     */
+    private static void computeEllipsePoints(Collection<int[]> points, int centerX, int centerY, int a, int b) {
+        int x = 0; // Initial x-coordinate
+        int y = b; // Initial y-coordinate
+
+        // Region 1: Initial decision parameter
+        double d1 = (b * b) - (a * a * b) + (0.25 * a * a); // Decision variable for region 1
+        double dx = 2.0 * b * b * x; // Change in x
+        double dy = 2.0 * a * a * y; // Change in y
+
+        // Region 1: When the slope is less than 1
+        while (dx < dy) {
+            addEllipsePoints(points, centerX, centerY, x, y);
+
+            // Update decision parameter and variables
+            if (d1 < 0) {
+                x++;
+                dx += (2 * b * b); // Update x change
+                d1 += dx + (b * b); // Update decision parameter
+            } else {
+                x++;
+                y--;
+                dx += (2 * b * b); // Update x change
+                dy -= (2 * a * a); // Update y change
+                d1 += dx - dy + (b * b); // Update decision parameter
+            }
+        }
+
+        // Region 2: Initial decision parameter for the second region
+        double d2 = b * b * (x + 0.5) * (x + 0.5) + a * a * (y - 1) * (y - 1) - a * a * b * b;
+
+        // Region 2: When the slope is greater than or equal to 1
+        while (y >= 0) {
+            addEllipsePoints(points, centerX, centerY, x, y);
+
+            // Update decision parameter and variables
+            if (d2 > 0) {
+                y--;
+                dy -= (2 * a * a); // Update y change
+                d2 += (a * a) - dy; // Update decision parameter
+            } else {
+                y--;
+                x++;
+                dx += (2 * b * b); // Update x change
+                dy -= (2 * a * a); // Update y change
+                d2 += dx - dy + (a * a); // Update decision parameter
+            }
+        }
+    }
+
+    /**
+     * Adds points for all four quadrants of the ellipse based on symmetry.
+     *
+     * @param points    the list to which points will be added
+     * @param centerX  the x-coordinate of the center of the ellipse
+     * @param centerY  the y-coordinate of the center of the ellipse
+     * @param x        the x-coordinate relative to the center
+     * @param y        the y-coordinate relative to the center
+     */
+    private static void addEllipsePoints(Collection<int[]> points, int centerX, int centerY, int x, int y) {
+        points.add(new int[] {centerX + x, centerY + y});
+        points.add(new int[] {centerX - x, centerY + y});
+        points.add(new int[] {centerX + x, centerY - y});
+        points.add(new int[] {centerX - x, centerY - y});
+    }
+}
diff --git a/src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java b/src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java
new file mode 100644
index 000000000000..9d03909c60ca
--- /dev/null
+++ b/src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java
@@ -0,0 +1,99 @@
+package com.thealgorithms.geometry;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+/**
+ * The {@code MidpointEllipseTest} class contains unit tests for the
+ * {@code MidpointEllipse} class, specifically testing the
+ * {@code drawEllipse} method.
+ *
+ * <p>This class uses parameterized tests to validate the output of
+ * Midpoint Ellipse algorithm for various input points.</p>
+ */
+class MidpointEllipseTest {
+
+    /**
+     * Provides test cases for the drawEllipse method.
+     * Each argument contains: centerX, centerY, a, b, and expected points.
+     *
+     * @return a stream of arguments for parameterized testing
+     */
+    static Stream<Arguments> ellipseTestProvider() {
+        return Stream.of(
+            Arguments.of(0, 0, 5, 3, new int[][] {{0, 3}, {0, 3}, {0, -3}, {0, -3}, {1, 3}, {-1, 3}, {1, -3}, {-1, -3}, {2, 3}, {-2, 3}, {2, -3}, {-2, -3}, {3, 2}, {-3, 2}, {3, -2}, {-3, -2}, {4, 2}, {-4, 2}, {4, -2}, {-4, -2}, {5, 1}, {-5, 1}, {5, -1}, {-5, -1}, {5, 0}, {-5, 0}, {5, 0}, {-5, 0}}),
+            Arguments.of(0, 0, 0, 5,
+                new int[][] {
+                    {0, -5}, {0, -4}, {0, -3}, {0, -2}, {0, -1}, {0, 0}, {0, 1}, {0, 2}, {0, 3}, {0, 4}, {0, 5} // Only vertical line points and center
+                }),
+            Arguments.of(0, 0, 5, 0,
+                new int[][] {
+                    {-5, 0}, {-4, 0}, {-3, 0}, {-2, 0}, {-1, 0}, {0, 0}, {1, 0}, {2, 0}, {3, 0}, {4, 0}, {5, 0} // Only horizontal line points and center
+                }),
+            Arguments.of(0, 0, 0, 0,
+                new int[][] {
+                    {0, 0} // Only center point
+                }),
+            Arguments.of(0, 0, 4, 4,
+                new int[][] {
+                    {0, 4},
+                    {0, 4},
+                    {0, -4},
+                    {0, -4},
+                    {1, 4},
+                    {-1, 4},
+                    {1, -4},
+                    {-1, -4},
+                    {2, 3},
+                    {-2, 3},
+                    {2, -3},
+                    {-2, -3},
+                    {3, 3},
+                    {-3, 3},
+                    {3, -3},
+                    {-3, -3},
+                    {3, 2},
+                    {-3, 2},
+                    {3, -2},
+                    {-3, -2},
+                    {4, 1},
+                    {-4, 1},
+                    {4, -1},
+                    {-4, -1},
+                    {4, 0},
+                    {-4, 0},
+                    {4, 0},
+                    {-4, 0},
+                }));
+    }
+
+    /**
+     * Tests the drawEllipse method with various parameters.
+     *
+     * @param centerX       the x-coordinate of the center of the ellipse
+     * @param centerY       the y-coordinate of the center of the ellipse
+     * @param a             the length of the semi-major axis
+     * @param b             the length of the semi-minor axis
+     * @param expectedPoints the expected points forming the ellipse
+     */
+    @ParameterizedTest
+    @MethodSource("ellipseTestProvider")
+    @DisplayName("Test drawing ellipses with various parameters")
+    void testDrawEllipse(int centerX, int centerY, int a, int b, int[][] expectedPoints) {
+        List<int[]> points = MidpointEllipse.drawEllipse(centerX, centerY, a, b);
+
+        // Validate the number of points and the specific points
+        assertEquals(expectedPoints.length, points.size(), "Number of points should match expected.");
+
+        for (int i = 0; i < expectedPoints.length; i++) {
+            assertArrayEquals(expectedPoints[i], points.get(i), "Point mismatch at index " + i);
+        }
+    }
+}

From 1577ec4e6241eef1b2c75ebb4124b07571074da7 Mon Sep 17 00:00:00 2001
From: UTSAV SINGHAL <119779889+UTSAVS26@users.noreply.github.com>
Date: Sat, 26 Oct 2024 15:40:20 +0530
Subject: [PATCH 0656/1338] Add Catalan number (#5846)

---
 .../thealgorithms/maths/CatalanNumbers.java   | 39 +++++++++++++++++
 .../maths/CatalanNumbersTest.java             | 43 +++++++++++++++++++
 2 files changed, 82 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/CatalanNumbers.java
 create mode 100644 src/test/java/com/thealgorithms/maths/CatalanNumbersTest.java

diff --git a/src/main/java/com/thealgorithms/maths/CatalanNumbers.java b/src/main/java/com/thealgorithms/maths/CatalanNumbers.java
new file mode 100644
index 000000000000..387756bdfa0c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/CatalanNumbers.java
@@ -0,0 +1,39 @@
+package com.thealgorithms.maths;
+
+/**
+ * Calculate Catalan Numbers
+ */
+public final class CatalanNumbers {
+    private CatalanNumbers() {
+    }
+
+    /**
+     * Calculate the nth Catalan number using a recursive formula.
+     *
+     * @param n the index of the Catalan number to compute
+     * @return the nth Catalan number
+     */
+    public static long catalan(final int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Index must be non-negative");
+        }
+        return factorial(2 * n) / (factorial(n + 1) * factorial(n));
+    }
+
+    /**
+     * Calculate the factorial of a number.
+     *
+     * @param n the number to compute the factorial for
+     * @return the factorial of n
+     */
+    private static long factorial(final int n) {
+        if (n == 0 || n == 1) {
+            return 1;
+        }
+        long result = 1;
+        for (int i = 2; i <= n; i++) {
+            result *= i;
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/CatalanNumbersTest.java b/src/test/java/com/thealgorithms/maths/CatalanNumbersTest.java
new file mode 100644
index 000000000000..2248ffd93732
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/CatalanNumbersTest.java
@@ -0,0 +1,43 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+/**
+ * Test class for CatalanNumbers
+ */
+class CatalanNumbersTest {
+
+    /**
+     * Provides test data for the parameterized Catalan number test.
+     * Each array contains two elements:
+     * [input number, expected Catalan number for that input]
+     */
+    static Stream<Object[]> catalanNumbersProvider() {
+        return Stream.of(new Object[] {0, 1}, new Object[] {1, 1}, new Object[] {2, 2}, new Object[] {3, 5}, new Object[] {4, 14}, new Object[] {5, 42}, new Object[] {6, 132}, new Object[] {7, 429}, new Object[] {8, 1430}, new Object[] {9, 4862}, new Object[] {10, 16796});
+    }
+
+    /**
+     * Parameterized test for checking the correctness of Catalan numbers.
+     * Uses the data from the provider method 'catalanNumbersProvider'.
+     */
+    @ParameterizedTest
+    @MethodSource("catalanNumbersProvider")
+    void testCatalanNumbers(int input, int expected) {
+        assertEquals(expected, CatalanNumbers.catalan(input), () -> String.format("Catalan number for input %d should be %d", input, expected));
+    }
+
+    /**
+     * Test for invalid inputs which should throw an IllegalArgumentException.
+     */
+    @Test
+    void testIllegalInput() {
+        assertThrows(IllegalArgumentException.class, () -> CatalanNumbers.catalan(-1));
+        assertThrows(IllegalArgumentException.class, () -> CatalanNumbers.catalan(-5));
+    }
+}

From 871e4df0d9e54755a5cbb8252317847c7dc0e7d9 Mon Sep 17 00:00:00 2001
From: Taranjeet Singh Kalsi <taranjeetkalsi15@gmail.com>
Date: Sat, 26 Oct 2024 16:49:16 +0530
Subject: [PATCH 0657/1338] Add another method to check Pronic number (#5919)

---
 .../com/thealgorithms/maths/PronicNumber.java | 14 +++++++
 .../thealgorithms/maths/PronicNumberTest.java | 37 +++++++------------
 2 files changed, 27 insertions(+), 24 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/PronicNumber.java b/src/main/java/com/thealgorithms/maths/PronicNumber.java
index 4891cf3c63b3..c2ad2a8139c8 100644
--- a/src/main/java/com/thealgorithms/maths/PronicNumber.java
+++ b/src/main/java/com/thealgorithms/maths/PronicNumber.java
@@ -21,6 +21,9 @@ private PronicNumber() {
      * @return true if input number is a pronic number, false otherwise
      */
     static boolean isPronic(int inputNumber) {
+        if (inputNumber == 0) {
+            return true;
+        }
         // Iterating from 0 to input_number
         for (int i = 0; i <= inputNumber; i++) {
             // Checking if product of i and (i+1) is equals input_number
@@ -34,4 +37,15 @@ static boolean isPronic(int inputNumber) {
         // equals input_number
         return false;
     }
+
+    /**
+     * This method checks if the given number is pronic number or non-pronic number using square root of number for finding divisors
+     *
+     * @param number Integer value which is to be checked if is a pronic number or not
+     * @return true if input number is a pronic number, false otherwise
+     */
+    public static boolean isPronicNumber(int number) {
+        int squareRoot = (int) Math.sqrt(number); // finding just smaller divisor of the number than its square root.
+        return squareRoot * (squareRoot + 1) == number;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/maths/PronicNumberTest.java b/src/test/java/com/thealgorithms/maths/PronicNumberTest.java
index 5a31981bed5c..8bf2b1852652 100644
--- a/src/test/java/com/thealgorithms/maths/PronicNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/PronicNumberTest.java
@@ -1,33 +1,22 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 public class PronicNumberTest {
 
-    @Test
-    void testForPronicNumber() {
-        // given
-        int number = 30;
-
-        // when
-        boolean result = PronicNumber.isPronic(number);
-
-        // then
-        assertTrue(result);
+    @ParameterizedTest
+    @ValueSource(ints = {0, 2, 6, 12, 20, 30, 42, 110, 272, 380, 420, 1260, 2550})
+    void testForPronicNumber(final int number) {
+        Assertions.assertTrue(PronicNumber.isPronic(number));
+        Assertions.assertTrue(PronicNumber.isPronicNumber(number));
     }
 
-    @Test
-    void testForNonPronicNumber() {
-        // given
-        int number = 21;
-
-        // when
-        boolean result = PronicNumber.isPronic(number);
-
-        // then
-        assertFalse(result);
+    @ParameterizedTest
+    @ValueSource(ints = {1, 4, 21, 36, 150, 2500})
+    void testForNonPronicNumber(final int number) {
+        Assertions.assertFalse(PronicNumber.isPronic(number));
+        Assertions.assertFalse(PronicNumber.isPronicNumber(number));
     }
 }

From 95875b0ae436b4b3aa3446200898eaf6e444e524 Mon Sep 17 00:00:00 2001
From: Taranjeet Singh Kalsi <taranjeetkalsi15@gmail.com>
Date: Sat, 26 Oct 2024 16:56:01 +0530
Subject: [PATCH 0658/1338] Add another method to find kth number (#5918)

---
 .../com/thealgorithms/maths/FindKthNumber.java  | 17 +++++++++++++++++
 .../thealgorithms/maths/FindKthNumberTest.java  | 13 +++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/src/main/java/com/thealgorithms/maths/FindKthNumber.java b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
index a9b267677eac..138d4b952be9 100644
--- a/src/main/java/com/thealgorithms/maths/FindKthNumber.java
+++ b/src/main/java/com/thealgorithms/maths/FindKthNumber.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.maths;
 
+import java.util.Collections;
+import java.util.PriorityQueue;
 import java.util.Random;
 
 /**
@@ -62,4 +64,19 @@ private static void swap(int[] array, int i, int j) {
         array[i] = array[j];
         array[j] = temp;
     }
+
+    public static int findKthMaxUsingHeap(int[] array, int k) {
+        if (k <= 0 || k > array.length) {
+            throw new IllegalArgumentException("k must be between 1 and the size of the array");
+        }
+        PriorityQueue<Integer> maxHeap = new PriorityQueue<>(Collections.reverseOrder()); // using max-heap to store numbers.
+        for (int num : array) {
+            maxHeap.add(num);
+        }
+        while (k > 1) {
+            maxHeap.poll(); // removing max number from heap
+            k--;
+        }
+        return maxHeap.peek();
+    }
 }
diff --git a/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java b/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java
index 21285a527c37..ca69e66c9f6a 100644
--- a/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java
@@ -14,21 +14,30 @@ public void testFindKthMaxTypicalCases() {
         assertEquals(3, FindKthNumber.findKthMax(array1, 3));
         assertEquals(4, FindKthNumber.findKthMax(array1, 2));
         assertEquals(5, FindKthNumber.findKthMax(array1, 1));
+        assertEquals(3, FindKthNumber.findKthMaxUsingHeap(array1, 3));
+        assertEquals(4, FindKthNumber.findKthMaxUsingHeap(array1, 2));
+        assertEquals(5, FindKthNumber.findKthMaxUsingHeap(array1, 1));
 
         int[] array2 = {7, 5, 8, 2, 1, 6};
         assertEquals(5, FindKthNumber.findKthMax(array2, 4));
         assertEquals(6, FindKthNumber.findKthMax(array2, 3));
         assertEquals(8, FindKthNumber.findKthMax(array2, 1));
+        assertEquals(5, FindKthNumber.findKthMaxUsingHeap(array2, 4));
+        assertEquals(6, FindKthNumber.findKthMaxUsingHeap(array2, 3));
+        assertEquals(8, FindKthNumber.findKthMaxUsingHeap(array2, 1));
     }
 
     @Test
     public void testFindKthMaxEdgeCases() {
         int[] array1 = {1};
         assertEquals(1, FindKthNumber.findKthMax(array1, 1));
+        assertEquals(1, FindKthNumber.findKthMaxUsingHeap(array1, 1));
 
         int[] array2 = {5, 3};
         assertEquals(5, FindKthNumber.findKthMax(array2, 1));
         assertEquals(3, FindKthNumber.findKthMax(array2, 2));
+        assertEquals(5, FindKthNumber.findKthMaxUsingHeap(array2, 1));
+        assertEquals(3, FindKthNumber.findKthMaxUsingHeap(array2, 2));
     }
 
     @Test
@@ -36,6 +45,8 @@ public void testFindKthMaxInvalidK() {
         int[] array = {1, 2, 3, 4, 5};
         assertThrows(IllegalArgumentException.class, () -> FindKthNumber.findKthMax(array, 0));
         assertThrows(IllegalArgumentException.class, () -> FindKthNumber.findKthMax(array, 6));
+        assertThrows(IllegalArgumentException.class, () -> FindKthNumber.findKthMaxUsingHeap(array, 0));
+        assertThrows(IllegalArgumentException.class, () -> FindKthNumber.findKthMaxUsingHeap(array, 6));
     }
 
     @Test
@@ -43,8 +54,10 @@ public void testFindKthMaxLargeArray() {
         int[] array = generateArray(1000);
         int k = new Random().nextInt(1, array.length);
         int result = FindKthNumber.findKthMax(array, k);
+        int maxK = FindKthNumber.findKthMaxUsingHeap(array, k);
         Arrays.sort(array);
         assertEquals(array[array.length - k], result);
+        assertEquals(array[array.length - k], maxK);
     }
 
     public static int[] generateArray(int capacity) {

From 921821214fb4a51dda558918e5d821ced2bff6a0 Mon Sep 17 00:00:00 2001
From: Taranjeet Singh Kalsi <taranjeetkalsi15@gmail.com>
Date: Sat, 26 Oct 2024 17:00:33 +0530
Subject: [PATCH 0659/1338] Add a new method to check Perfect Square (#5917)

---
 .../java/com/thealgorithms/maths/PerfectSquare.java  | 12 ++++++++++++
 .../com/thealgorithms/maths/PerfectSquareTest.java   |  2 ++
 2 files changed, 14 insertions(+)

diff --git a/src/main/java/com/thealgorithms/maths/PerfectSquare.java b/src/main/java/com/thealgorithms/maths/PerfectSquare.java
index fbc7a6f19bd0..e9318bd7d805 100644
--- a/src/main/java/com/thealgorithms/maths/PerfectSquare.java
+++ b/src/main/java/com/thealgorithms/maths/PerfectSquare.java
@@ -18,4 +18,16 @@ public static boolean isPerfectSquare(final int number) {
         final int sqrt = (int) Math.sqrt(number);
         return sqrt * sqrt == number;
     }
+
+    /**
+     * Check if a number is perfect square or not
+     *
+     * @param number number to be checked
+     * @return {@code true} if {@code number} is perfect square, otherwise
+     * {@code false}
+     */
+    public static boolean isPerfectSquareUsingPow(long number) {
+        long a = (long) Math.pow(number, 1.0 / 2);
+        return a * a == number;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java b/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java
index 08c96bc71f9b..2bda5bfd6cf8 100644
--- a/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java
+++ b/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java
@@ -9,11 +9,13 @@ public class PerfectSquareTest {
     @ValueSource(ints = {0, 1, 2 * 2, 3 * 3, 4 * 4, 5 * 5, 6 * 6, 7 * 7, 8 * 8, 9 * 9, 10 * 10, 11 * 11, 123 * 123})
     void positiveTest(final int number) {
         Assertions.assertTrue(PerfectSquare.isPerfectSquare(number));
+        Assertions.assertTrue(PerfectSquare.isPerfectSquareUsingPow(number));
     }
 
     @ParameterizedTest
     @ValueSource(ints = {-1, -2, -3, -4, -5, -100, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 17, 99, 101, 257, 999, 1001})
     void negativeTest(final int number) {
         Assertions.assertFalse(PerfectSquare.isPerfectSquare(number));
+        Assertions.assertFalse(PerfectSquare.isPerfectSquareUsingPow(number));
     }
 }

From 7cf568c9758aa3eefa1470abd7fe8c8b0adf953c Mon Sep 17 00:00:00 2001
From: Saahil Mahato <115351000+saahil-mahato@users.noreply.github.com>
Date: Sat, 26 Oct 2024 17:35:33 +0545
Subject: [PATCH 0660/1338] Add midpoint circle algorithm (#5868)

---
 .../geometry/MidpointCircle.java              | 85 +++++++++++++++++++
 .../geometry/MidpointCircleTest.java          | 55 ++++++++++++
 2 files changed, 140 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/geometry/MidpointCircle.java
 create mode 100644 src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java

diff --git a/src/main/java/com/thealgorithms/geometry/MidpointCircle.java b/src/main/java/com/thealgorithms/geometry/MidpointCircle.java
new file mode 100644
index 000000000000..803e8bb42b53
--- /dev/null
+++ b/src/main/java/com/thealgorithms/geometry/MidpointCircle.java
@@ -0,0 +1,85 @@
+package com.thealgorithms.geometry;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Class to represent the Midpoint Circle Algorithm.
+ * This algorithm calculates points on the circumference of a circle
+ * using integer arithmetic for efficient computation.
+ */
+public final class MidpointCircle {
+
+    private MidpointCircle() {
+        // Private Constructor to prevent instantiation.
+    }
+
+    /**
+     * Generates points on the circumference of a circle using the midpoint circle algorithm.
+     *
+     * @param centerX The x-coordinate of the circle's center.
+     * @param centerY The y-coordinate of the circle's center.
+     * @param radius  The radius of the circle.
+     * @return A list of points on the circle, each represented as an int[] with 2 elements [x, y].
+     */
+    public static List<int[]> generateCirclePoints(int centerX, int centerY, int radius) {
+        List<int[]> points = new ArrayList<>();
+
+        // Special case for radius 0, only the center point should be added.
+        if (radius == 0) {
+            points.add(new int[] {centerX, centerY});
+            return points;
+        }
+
+        // Start at (radius, 0)
+        int x = radius;
+        int y = 0;
+
+        // Decision parameter
+        int p = 1 - radius;
+
+        // Add the initial points in all octants
+        addSymmetricPoints(points, centerX, centerY, x, y);
+
+        // Iterate while x > y
+        while (x > y) {
+            y++;
+
+            if (p <= 0) {
+                // Midpoint is inside or on the circle
+                p = p + 2 * y + 1;
+            } else {
+                // Midpoint is outside the circle
+                x--;
+                p = p + 2 * y - 2 * x + 1;
+            }
+
+            // Add points for this (x, y)
+            addSymmetricPoints(points, centerX, centerY, x, y);
+        }
+
+        return points;
+    }
+
+    /**
+     * Adds the symmetric points in all octants of the circle based on the current x and y values.
+     *
+     * @param points  The list to which symmetric points will be added.
+     * @param centerX The x-coordinate of the circle's center.
+     * @param centerY The y-coordinate of the circle's center.
+     * @param x       The current x-coordinate on the circumference.
+     * @param y       The current y-coordinate on the circumference.
+     */
+    private static void addSymmetricPoints(Collection<int[]> points, int centerX, int centerY, int x, int y) {
+        // Octant symmetry points
+        points.add(new int[] {centerX + x, centerY + y});
+        points.add(new int[] {centerX - x, centerY + y});
+        points.add(new int[] {centerX + x, centerY - y});
+        points.add(new int[] {centerX - x, centerY - y});
+        points.add(new int[] {centerX + y, centerY + x});
+        points.add(new int[] {centerX - y, centerY + x});
+        points.add(new int[] {centerX + y, centerY - x});
+        points.add(new int[] {centerX - y, centerY - x});
+    }
+}
diff --git a/src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java b/src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java
new file mode 100644
index 000000000000..24370cd43b25
--- /dev/null
+++ b/src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.geometry;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+/**
+ * Test class for the {@code MidpointCircle} class
+ */
+class MidpointCircleTest {
+
+    /**
+     * Parameterized test to check the generated points for different circles.
+     * The points are checked based on the expected center and radius.
+     *
+     * @param centerX The x-coordinate of the circle's center.
+     * @param centerY The y-coordinate of the circle's center.
+     * @param radius  The radius of the circle.
+     */
+    @ParameterizedTest
+    @CsvSource({
+        "0, 0, 3", // Circle centered at (0, 0) with radius 3
+        "10, 10, 2" // Circle centered at (10, 10) with radius 2
+    })
+    void
+    testGenerateCirclePoints(int centerX, int centerY, int radius) {
+        List<int[]> points = MidpointCircle.generateCirclePoints(centerX, centerY, radius);
+
+        // Ensure that all points satisfy the circle equation (x - centerX)^2 + (y - centerY)^2 = radius^2
+        for (int[] point : points) {
+            int x = point[0];
+            int y = point[1];
+
+            int dx = x - centerX;
+            int dy = y - centerY;
+            int distanceSquared = dx * dx + dy * dy;
+
+            assertTrue(Math.abs(distanceSquared - radius * radius) <= 1, "Point (" + x + ", " + y + ") does not satisfy the circle equation.");
+        }
+    }
+
+    /**
+     * Test to ensure the algorithm generates points for a zero-radius circle.
+     */
+    @Test
+    void testZeroRadiusCircle() {
+        List<int[]> points = MidpointCircle.generateCirclePoints(0, 0, 0);
+
+        // A zero-radius circle should only have one point: (0, 0)
+        assertTrue(points.size() == 1 && points.get(0)[0] == 0 && points.get(0)[1] == 0, "Zero-radius circle did not generate the correct point.");
+    }
+}

From 73416e2f0cddb5b22debc8d1c4e2ca37483998c9 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 17:33:40 +0530
Subject: [PATCH 0661/1338] Add `BandwidthAllocation` algorithm (#5807)

---
 DIRECTORY.md                                  |  8 +++
 .../greedyalgorithms/BandwidthAllocation.java | 58 +++++++++++++++++++
 .../BandwidthAllocationTest.java              | 22 +++++++
 3 files changed, 88 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java
 create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 10922d761952..b7707a254ab6 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -320,11 +320,14 @@
             * [BresenhamLine](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/BresenhamLine.java)
             * [ConvexHull](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/ConvexHull.java)
             * [GrahamScan](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/GrahamScan.java)
+            * [MidpointCircle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/MidpointCircle.java)
+            * [MidpointEllipse](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/MidpointEllipse.java)
             * [Point](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/Point.java)
           * graph
             * [StronglyConnectedComponentOptimized](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
           * greedyalgorithms
             * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
+            * [BandwidthAllocation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java)
             * [BinaryAddition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java)
             * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java)
             * [DigitSeparation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java)
@@ -360,6 +363,7 @@
             * [Average](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Average.java)
             * [BinaryPow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinaryPow.java)
             * [BinomialCoefficient](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java)
+            * [CatalanNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CatalanNumbers.java)
             * [Ceil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Ceil.java)
             * [ChineseRemainderTheorem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java)
             * [CircularConvolutionFFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java)
@@ -967,10 +971,13 @@
             * [BresenhamLineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java)
             * [ConvexHullTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java)
             * [GrahamScanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
+            * [MidpointCircleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java)
+            * [MidpointEllipseTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java)
           * graph
             * [StronglyConnectedComponentOptimizedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)
           * greedyalgorithms
             * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
+            * [BandwidthAllocationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java)
             * [BinaryAdditionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java)
             * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java)
             * [DigitSeparationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java)
@@ -1003,6 +1010,7 @@
             * [AverageTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AverageTest.java)
             * [BinaryPowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinaryPowTest.java)
             * [BinomialCoefficientTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinomialCoefficientTest.java)
+            * [CatalanNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CatalanNumbersTest.java)
             * [CeilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CeilTest.java)
             * [ChineseRemainderTheoremTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java)
             * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java b/src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java
new file mode 100644
index 000000000000..602cdcd5ad40
--- /dev/null
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.Arrays;
+
+/**
+ * Class to solve the Bandwidth Allocation Problem.
+ * The goal is to maximize the value gained by allocating bandwidth to users.
+ * Example:
+ * Bandwidth = 10
+ * Users = [3, 5, 7]
+ * Values = [10, 20, 30]
+ * The maximum value achievable is 40 by allocating 3 units to user 0 and 7 units to user 2.
+ *
+ * @author Hardvan
+ */
+public final class BandwidthAllocation {
+    private BandwidthAllocation() {
+    }
+
+    /**
+     * Allocates bandwidth to maximize value.
+     * Steps:
+     * 1. Calculate the ratio of value/demand for each user.
+     * 2. Sort the users in descending order of the ratio.
+     * 3. Allocate bandwidth to users in order of the sorted list.
+     * 4. If the bandwidth is not enough to allocate the full demand of a user, allocate a fraction of the demand.
+     * 5. Return the maximum value achievable.
+     *
+     * @param bandwidth total available bandwidth to allocate
+     * @param users     array of user demands
+     * @param values    array of values associated with each user's demand
+     * @return the maximum value achievable
+     */
+    public static int maxValue(int bandwidth, int[] users, int[] values) {
+        int n = users.length;
+        double[][] ratio = new double[n][2]; // {index, ratio}
+
+        for (int i = 0; i < n; i++) {
+            ratio[i][0] = i;
+            ratio[i][1] = (double) values[i] / users[i];
+        }
+
+        Arrays.sort(ratio, (a, b) -> Double.compare(b[1], a[1]));
+
+        int maxValue = 0;
+        for (int i = 0; i < n; i++) {
+            int index = (int) ratio[i][0];
+            if (bandwidth >= users[index]) {
+                maxValue += values[index];
+                bandwidth -= users[index];
+            } else {
+                maxValue += (int) (ratio[i][1] * bandwidth);
+                break;
+            }
+        }
+        return maxValue;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java
new file mode 100644
index 000000000000..452f7858c162
--- /dev/null
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class BandwidthAllocationTest {
+
+    @ParameterizedTest
+    @MethodSource("bandwidthProvider")
+    public void testMaxValue(int capacity, int[] bandwidths, int[] values, int expected) {
+        assertEquals(expected, BandwidthAllocation.maxValue(capacity, bandwidths, values));
+    }
+
+    private static Stream<Arguments> bandwidthProvider() {
+        return Stream.of(Arguments.of(50, new int[] {20, 10, 30}, new int[] {40, 20, 30}, 80), Arguments.of(0, new int[] {5, 10}, new int[] {10, 20}, 0), Arguments.of(5, new int[] {5, 10}, new int[] {10, 20}, 10), Arguments.of(15, new int[] {10, 20}, new int[] {10, 25}, 18),
+            Arguments.of(25, new int[] {10, 15, 20}, new int[] {10, 30, 50}, 60));
+    }
+}

From f20f8d18360c074b1ea70e3760ca90a8651a3f7e Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 17:37:21 +0530
Subject: [PATCH 0662/1338] Enhance docs, add more tests in `AffineConverter`
 (#5915)

---
 .../conversions/AffineConverter.java          | 45 +++++++++++++++-
 .../conversions/AffineConverterTest.java      | 54 +++++++++++++++----
 2 files changed, 86 insertions(+), 13 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/AffineConverter.java b/src/main/java/com/thealgorithms/conversions/AffineConverter.java
index a580b23f90f9..199a6dd517d5 100644
--- a/src/main/java/com/thealgorithms/conversions/AffineConverter.java
+++ b/src/main/java/com/thealgorithms/conversions/AffineConverter.java
@@ -1,23 +1,64 @@
 package com.thealgorithms.conversions;
 
+/**
+ * A utility class to perform affine transformations of the form:
+ * y = slope * x + intercept.
+ *
+ * This class supports inversion and composition of affine transformations.
+ * It is immutable, meaning each instance represents a fixed transformation.
+ */
 public final class AffineConverter {
     private final double slope;
     private final double intercept;
+
+    /**
+     * Constructs an AffineConverter with the given slope and intercept.
+     *
+     * @param inSlope The slope of the affine transformation.
+     * @param inIntercept The intercept (constant term) of the affine transformation.
+     * @throws IllegalArgumentException if either parameter is NaN.
+     */
     public AffineConverter(final double inSlope, final double inIntercept) {
+        if (Double.isNaN(inSlope) || Double.isNaN(inIntercept)) {
+            throw new IllegalArgumentException("Slope and intercept must be valid numbers.");
+        }
         slope = inSlope;
         intercept = inIntercept;
     }
 
+    /**
+     * Converts the given input value using the affine transformation:
+     * result = slope * inValue + intercept.
+     *
+     * @param inValue The input value to convert.
+     * @return The transformed value.
+     */
     public double convert(final double inValue) {
         return slope * inValue + intercept;
     }
 
+    /**
+     * Returns a new AffineConverter representing the inverse of the current transformation.
+     * The inverse of y = slope * x + intercept is x = (y - intercept) / slope.
+     *
+     * @return A new AffineConverter representing the inverse transformation.
+     * @throws AssertionError if the slope is zero, as the inverse would be undefined.
+     */
     public AffineConverter invert() {
-        assert slope != 0.0;
+        assert slope != 0.0 : "Slope cannot be zero for inversion.";
         return new AffineConverter(1.0 / slope, -intercept / slope);
     }
 
+    /**
+     * Composes this affine transformation with another, returning a new AffineConverter.
+     * If this transformation is f(x) and the other is g(x), the result is f(g(x)).
+     *
+     * @param other Another AffineConverter to compose with.
+     * @return A new AffineConverter representing the composition of the two transformations.
+     */
     public AffineConverter compose(final AffineConverter other) {
-        return new AffineConverter(slope * other.slope, slope * other.intercept + intercept);
+        double newSlope = slope * other.slope;
+        double newIntercept = slope * other.intercept + intercept;
+        return new AffineConverter(newSlope, newIntercept);
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/AffineConverterTest.java b/src/test/java/com/thealgorithms/conversions/AffineConverterTest.java
index 2705955f68f6..47eea139f424 100644
--- a/src/test/java/com/thealgorithms/conversions/AffineConverterTest.java
+++ b/src/test/java/com/thealgorithms/conversions/AffineConverterTest.java
@@ -16,31 +16,39 @@ void setUp() {
     }
 
     @Test
-    void testConstructor() {
+    void testConstructorWithValidValues() {
         assertEquals(3.0, converter.convert(0.0), "Expected value when input is 0.0");
         assertEquals(5.0, converter.convert(1.0), "Expected value when input is 1.0");
-        assertEquals(7.0, converter.convert(2.0), "Expected value when input is 2.0");
     }
 
     @Test
-    void testConvert() {
-        assertEquals(3.0, converter.convert(0.0), "Conversion at 0.0 should equal the intercept");
-        assertEquals(7.0, converter.convert(2.0), "2.0 should convert to 7.0");
-        assertEquals(11.0, converter.convert(4.0), "4.0 should convert to 11.0");
+    void testConstructorWithInvalidValues() {
+        assertThrows(IllegalArgumentException.class, () -> new AffineConverter(Double.NaN, 3.0), "Constructor should throw IllegalArgumentException for NaN slope");
+    }
+
+    @Test
+    void testConvertWithNegativeValues() {
+        assertEquals(-1.0, converter.convert(-2.0), "Negative input should convert correctly");
+        assertEquals(-3.0, new AffineConverter(-1.0, -1.0).convert(2.0), "Slope and intercept can be negative");
+    }
+
+    @Test
+    void testConvertWithFloatingPointPrecision() {
+        double result = new AffineConverter(1.3333, 0.6667).convert(3.0);
+        assertEquals(4.6666, result, 1e-4, "Conversion should maintain floating-point precision");
     }
 
     @Test
     void testInvert() {
         AffineConverter inverted = converter.invert();
-        assertEquals(0.0, inverted.convert(3.0), "Inverted converter should return 0.0 for input 3.0");
-        assertEquals(1.0, inverted.convert(5.0), "Inverted converter should return 1.0 for input 5.0");
-        assertEquals(2.0, inverted.convert(7.0), "Inverted converter should return 2.0 for input 7.0");
+        assertEquals(0.0, inverted.convert(3.0), "Inverted should return 0.0 for input 3.0");
+        assertEquals(1.0, inverted.convert(5.0), "Inverted should return 1.0 for input 5.0");
     }
 
     @Test
     void testInvertWithZeroSlope() {
         AffineConverter zeroSlopeConverter = new AffineConverter(0.0, 3.0);
-        assertThrows(AssertionError.class, zeroSlopeConverter::invert, "Invert should throw assertion error when slope is zero");
+        assertThrows(AssertionError.class, zeroSlopeConverter::invert, "Invert should throw AssertionError when slope is zero");
     }
 
     @Test
@@ -50,6 +58,30 @@ void testCompose() {
 
         assertEquals(7.0, composed.convert(0.0), "Expected composed conversion at 0.0");
         assertEquals(9.0, composed.convert(1.0), "Expected composed conversion at 1.0");
-        assertEquals(11.0, composed.convert(2.0), "Expected composed conversion at 2.0");
+    }
+
+    @Test
+    void testMultipleCompositions() {
+        AffineConverter c1 = new AffineConverter(2.0, 1.0);
+        AffineConverter c2 = new AffineConverter(3.0, -2.0);
+        AffineConverter c3 = c1.compose(c2); // (2x + 1) ∘ (3x - 2) => 6x - 1
+
+        assertEquals(-3.0, c3.convert(0.0), "Composed transformation should return -3.0 at 0.0");
+        assertEquals(3.0, c3.convert(1.0), "Composed transformation should return 3.0 at 1.0");
+    }
+
+    @Test
+    void testIdentityComposition() {
+        AffineConverter identity = new AffineConverter(1.0, 0.0);
+        AffineConverter composed = converter.compose(identity);
+
+        assertEquals(3.0, composed.convert(0.0), "Identity composition should not change the transformation");
+        assertEquals(7.0, composed.convert(2.0), "Identity composition should behave like the original");
+    }
+
+    @Test
+    void testLargeInputs() {
+        double largeValue = 1e6;
+        assertEquals(2.0 * largeValue + 3.0, converter.convert(largeValue), "Should handle large input values without overflow");
     }
 }

From 04e421b8370ceab14b6e81c1adeaffad1841d406 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 17:42:55 +0530
Subject: [PATCH 0663/1338] Add `SlidingWindowMaximum` algorithm (#5839)

---
 DIRECTORY.md                                  |  2 +
 .../queues/SlidingWindowMaximum.java          | 63 +++++++++++++++++++
 .../queues/SlidingWindowMaximumTest.java      | 50 +++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximum.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximumTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b7707a254ab6..bad138b341e1 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -207,6 +207,7 @@
               * [PriorityQueues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java)
               * [Queue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/Queue.java)
               * [QueueByTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java)
+              * [SlidingWindowMaximum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximum.java)
               * [TokenBucket](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/TokenBucket.java)
             * stacks
               * [NodeStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java)
@@ -882,6 +883,7 @@
               * [PriorityQueuesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java)
               * [QueueByTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java)
               * [QueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java)
+              * [SlidingWindowMaximumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximumTest.java)
               * [TokenBucketTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/TokenBucketTest.java)
             * stacks
               * [NodeStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximum.java b/src/main/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximum.java
new file mode 100644
index 000000000000..d6720dd01e29
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximum.java
@@ -0,0 +1,63 @@
+package com.thealgorithms.datastructures.queues;
+
+import java.util.Deque;
+import java.util.LinkedList;
+
+/**
+ * The {@code SlidingWindowMaximum} class provides a method to efficiently compute
+ * the maximum element within every sliding window of size {@code k} in a given array.
+ *
+ * <p>The algorithm uses a deque to maintain the indices of useful elements within
+ * the current sliding window. The time complexity of this approach is O(n) since
+ * each element is processed at most twice.
+ *
+ * @author Hardvan
+ */
+public final class SlidingWindowMaximum {
+    private SlidingWindowMaximum() {
+    }
+
+    /**
+     * Returns an array of the maximum values for each sliding window of size {@code k}.
+     * <p>If {@code nums} has fewer elements than {@code k}, the result will be an empty array.
+     * <p>Example:
+     * <pre>
+     * Input: nums = [1, 3, -1, -3, 5, 3, 6, 7], k = 3
+     * Output: [3, 3, 5, 5, 6, 7]
+     * </pre>
+     *
+     * @param nums the input array of integers
+     * @param k the size of the sliding window
+     * @return an array containing the maximum element for each sliding window
+     */
+    public static int[] maxSlidingWindow(int[] nums, int k) {
+        int n = nums.length;
+        if (n < k || k == 0) {
+            return new int[0];
+        }
+
+        int[] result = new int[n - k + 1];
+        Deque<Integer> deque = new LinkedList<>();
+        for (int i = 0; i < n; i++) {
+            // Remove elements from the front of the deque if they are out of the current window
+            if (!deque.isEmpty() && deque.peekFirst() < i - k + 1) {
+                deque.pollFirst();
+            }
+
+            // Remove elements from the back if they are smaller than the current element
+            while (!deque.isEmpty() && nums[deque.peekLast()] < nums[i]) {
+                deque.pollLast();
+            }
+
+            // Add the current element's index to the deque
+            deque.offerLast(i);
+
+            // Store the maximum element for the current window (starting from the k-1th element)
+            if (i >= k - 1) {
+                result[i - k + 1] = nums[deque.peekFirst()];
+            }
+        }
+
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximumTest.java b/src/test/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximumTest.java
new file mode 100644
index 000000000000..e435f9192a88
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximumTest.java
@@ -0,0 +1,50 @@
+package com.thealgorithms.datastructures.queues;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class SlidingWindowMaximumTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testMaxSlidingWindow(int[] nums, int k, int[] expected) {
+        assertArrayEquals(expected, SlidingWindowMaximum.maxSlidingWindow(nums, k));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            // Test case 1: Example from the problem statement
+            Arguments.of(new int[] {1, 3, -1, -3, 5, 3, 6, 7}, 3, new int[] {3, 3, 5, 5, 6, 7}),
+
+            // Test case 2: All elements are the same
+            Arguments.of(new int[] {4, 4, 4, 4, 4}, 2, new int[] {4, 4, 4, 4}),
+
+            // Test case 3: Window size equals the array length
+            Arguments.of(new int[] {2, 1, 5, 3, 6}, 5, new int[] {6}),
+
+            // Test case 4: Single element array with window size 1
+            Arguments.of(new int[] {7}, 1, new int[] {7}),
+
+            // Test case 5: Window size larger than the array length
+            Arguments.of(new int[] {1, 2, 3}, 4, new int[] {}),
+
+            // Test case 6: Decreasing sequence
+            Arguments.of(new int[] {9, 8, 7, 6, 5, 4}, 3, new int[] {9, 8, 7, 6}),
+
+            // Test case 7: Increasing sequence
+            Arguments.of(new int[] {1, 2, 3, 4, 5}, 2, new int[] {2, 3, 4, 5}),
+
+            // Test case 8: k is zero
+            Arguments.of(new int[] {1, 3, -1, -3, 5, 3, 6, 7}, 0, new int[] {}),
+
+            // Test case 9: Array with negative numbers
+            Arguments.of(new int[] {-4, -2, -5, -1, -3}, 3, new int[] {-2, -1, -1}),
+
+            // Test case 10: Empty array
+            Arguments.of(new int[] {}, 3, new int[] {}));
+    }
+}

From 9e1dd86a0814cbc142cd43a3571bd46aa8500d6f Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 17:49:37 +0530
Subject: [PATCH 0664/1338] Add `MergeKSortedArrays` algorithm (#5838)

---
 DIRECTORY.md                                  |  2 +
 .../heaps/MergeKSortedArrays.java             | 60 +++++++++++++++++++
 .../heaps/MergeKSortedArraysTest.java         | 41 +++++++++++++
 3 files changed, 103 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/heaps/MergeKSortedArrays.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/heaps/MergeKSortedArraysTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index bad138b341e1..28bd525bb508 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -179,6 +179,7 @@
               * [LeftistHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java)
               * [MaxHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java)
               * [MedianFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MedianFinder.java)
+              * [MergeKSortedArrays](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MergeKSortedArrays.java)
               * [MinHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java)
               * [MinPriorityQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java)
             * lists
@@ -860,6 +861,7 @@
               * [KthElementFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java)
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
               * [MedianFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java)
+              * [MergeKSortedArraysTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MergeKSortedArraysTest.java)
               * [MinPriorityQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java)
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MergeKSortedArrays.java b/src/main/java/com/thealgorithms/datastructures/heaps/MergeKSortedArrays.java
new file mode 100644
index 000000000000..e41711f05914
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MergeKSortedArrays.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.datastructures.heaps;
+
+import java.util.Comparator;
+import java.util.PriorityQueue;
+
+/**
+ * This class provides a method to merge multiple sorted arrays into a single sorted array.
+ * It utilizes a min-heap to efficiently retrieve the smallest elements from each array.
+ *
+ * Time Complexity: O(n * log k), where n is the total number of elements across all arrays
+ * and k is the number of arrays.
+ *
+ * Space Complexity: O(k) for the heap, where k is the number of arrays.
+ *
+ * @author Hardvan
+ */
+public final class MergeKSortedArrays {
+    private MergeKSortedArrays() {
+    }
+
+    /**
+     * Merges k sorted arrays into one sorted array using a min-heap.
+     * Steps:
+     * 1. Create a min-heap to store elements in the format: {value, array index, element index}
+     * 2. Add the first element from each array to the heap
+     * 3. While the heap is not empty, remove the smallest element from the heap
+     *   and add it to the result array. If there are more elements in the same array,
+     *   add the next element to the heap.
+     *   Continue until all elements have been processed.
+     *   The result array will contain all elements in sorted order.
+     * 4. Return the result array.
+     *
+     * @param arrays a 2D array, where each subarray is sorted in non-decreasing order
+     * @return a single sorted array containing all elements from the input arrays
+     */
+    public static int[] mergeKArrays(int[][] arrays) {
+        PriorityQueue<int[]> minHeap = new PriorityQueue<>(Comparator.comparingInt(a -> a[0]));
+
+        int totalLength = 0;
+        for (int i = 0; i < arrays.length; i++) {
+            if (arrays[i].length > 0) {
+                minHeap.offer(new int[] {arrays[i][0], i, 0});
+                totalLength += arrays[i].length;
+            }
+        }
+
+        int[] result = new int[totalLength];
+        int index = 0;
+        while (!minHeap.isEmpty()) {
+            int[] top = minHeap.poll();
+            result[index++] = top[0];
+
+            if (top[2] + 1 < arrays[top[1]].length) {
+                minHeap.offer(new int[] {arrays[top[1]][top[2] + 1], top[1], top[2] + 1});
+            }
+        }
+
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/MergeKSortedArraysTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/MergeKSortedArraysTest.java
new file mode 100644
index 000000000000..c9b754619286
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/MergeKSortedArraysTest.java
@@ -0,0 +1,41 @@
+package com.thealgorithms.datastructures.heaps;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class MergeKSortedArraysTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testMergeKArrays(int[][] arrays, int[] expected) {
+        assertArrayEquals(expected, MergeKSortedArrays.mergeKArrays(arrays));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            // Basic test case with multiple arrays
+            Arguments.of(new int[][] {{1, 4, 5}, {1, 3, 4}, {2, 6}}, new int[] {1, 1, 2, 3, 4, 4, 5, 6}),
+
+            // Edge case: All arrays are empty
+            Arguments.of(new int[][] {{}, {}, {}}, new int[] {}),
+
+            // Edge case: One array is empty
+            Arguments.of(new int[][] {{1, 3, 5}, {}, {2, 4, 6}}, new int[] {1, 2, 3, 4, 5, 6}),
+
+            // Single array
+            Arguments.of(new int[][] {{1, 2, 3}}, new int[] {1, 2, 3}),
+
+            // Arrays with negative numbers
+            Arguments.of(new int[][] {{-5, 1, 3}, {-10, 0, 2}}, new int[] {-10, -5, 0, 1, 2, 3}),
+
+            // Arrays with duplicate elements
+            Arguments.of(new int[][] {{1, 1, 2}, {1, 3, 3}, {2, 2, 4}}, new int[] {1, 1, 1, 2, 2, 2, 3, 3, 4}),
+
+            // Edge case: Arrays of varying lengths
+            Arguments.of(new int[][] {{1, 2}, {3}, {4, 5, 6, 7}}, new int[] {1, 2, 3, 4, 5, 6, 7}));
+    }
+}

From 94daff0895841fd88a664f6cfb4b64c06f84de7b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 20:01:11 +0530
Subject: [PATCH 0665/1338] Add `NextHigherSameBitCount` algorithm (#5865)

---
 DIRECTORY.md                                  |  2 ++
 .../NextHigherSameBitCount.java               | 30 +++++++++++++++++++
 .../NextHigherSameBitCountTest.java           | 22 ++++++++++++++
 3 files changed, 54 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCount.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCountTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 28bd525bb508..7bc9cea37760 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -41,6 +41,7 @@
             * [IsPowerTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java)
             * [LowestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/LowestSetBit.java)
             * [ModuloPowerOfTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwo.java)
+            * [NextHigherSameBitCount](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCount.java)
             * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
             * [NumberAppearingOddTimes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
@@ -744,6 +745,7 @@
             * [IsPowerTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java)
             * [LowestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java)
             * [ModuloPowerOfTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwoTest.java)
+            * [NextHigherSameBitCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCountTest.java)
             * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
             * [NumberAppearingOddTimesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCount.java b/src/main/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCount.java
new file mode 100644
index 000000000000..6a764d806279
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCount.java
@@ -0,0 +1,30 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class provides a method to find the next higher number
+ * with the same number of set bits as the given number.
+ *
+ * @author Hardvan
+ */
+public final class NextHigherSameBitCount {
+    private NextHigherSameBitCount() {
+    }
+
+    /**
+     * Finds the next higher integer with the same number of set bits.
+     * Steps:
+     * 1. Find {@code c}, the rightmost set bit of {@code n}.
+     * 2. Find {@code r}, the rightmost set bit of {@code n + c}.
+     * 3. Swap the bits of {@code r} and {@code n} to the right of {@code c}.
+     * 4. Shift the bits of {@code r} and {@code n} to the right of {@code c} to the rightmost.
+     * 5. Combine the results of steps 3 and 4.
+     *
+     * @param n the input number
+     * @return the next higher integer with the same set bit count
+     */
+    public static int nextHigherSameBitCount(int n) {
+        int c = n & -n;
+        int r = n + c;
+        return (((r ^ n) >> 2) / c) | r;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCountTest.java b/src/test/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCountTest.java
new file mode 100644
index 000000000000..c8fb9ef21b60
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCountTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class NextHigherSameBitCountTest {
+
+    @ParameterizedTest
+    @CsvSource({
+        "5, 6", // 101 -> 110
+        "7, 11", // 0111 -> 1011
+        "3, 5", // 011 -> 101
+        "12, 17", // 001100 -> 010001
+        "15, 23" // 01111 -> 10111
+    })
+    void
+    testNextHigherSameBitCount(int input, int expected) {
+        assertEquals(expected, NextHigherSameBitCount.nextHigherSameBitCount(input));
+    }
+}

From 196cc60982048d88a22fd81f1587b8b8b2572259 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 20:10:17 +0530
Subject: [PATCH 0666/1338] Add `AllConstruct` algorithm (#5791)

---
 DIRECTORY.md                                  |  2 +
 .../dynamicprogramming/AllConstruct.java      | 61 +++++++++++++++++++
 .../dynamicprogramming/AllConstructTest.java  | 38 ++++++++++++
 3 files changed, 101 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/AllConstruct.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7bc9cea37760..9ebbd484376b 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -275,6 +275,7 @@
             * [TilingProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/TilingProblem.java)
           * dynamicprogramming
             * [Abbreviation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Abbreviation.java)
+            * [AllConstruct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/AllConstruct.java)
             * [AssignmentUsingBitmask](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmask.java)
             * [BoardPath](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java)
             * [BoundaryFill](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java)
@@ -930,6 +931,7 @@
             * [TilingProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/TilingProblemTest.java)
           * dynamicprogramming
             * [AbbreviationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/AbbreviationTest.java)
+            * [AllConstructTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java)
             * [AssignmentUsingBitmaskTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java)
             * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
             * [BoundaryFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java)
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/AllConstruct.java b/src/main/java/com/thealgorithms/dynamicprogramming/AllConstruct.java
new file mode 100644
index 000000000000..e7712b13a2b7
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/AllConstruct.java
@@ -0,0 +1,61 @@
+package com.thealgorithms.dynamicprogramming;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * This class provides a solution to the "All Construct" problem.
+ *
+ * The problem is to determine all the ways a target string can be constructed
+ * from a given list of substrings. Each substring in the word bank can be used
+ * multiple times, and the order of substrings matters.
+ *
+ * @author Hardvan
+ */
+public final class AllConstruct {
+    private AllConstruct() {
+    }
+
+    /**
+     * Finds all possible ways to construct the target string using substrings
+     * from the given word bank.
+     * Time Complexity: O(n * m * k), where n = length of the target,
+     * m = number of words in wordBank, and k = average length of a word.
+     *
+     * Space Complexity: O(n * m) due to the size of the table storing combinations.
+     *
+     * @param target   The target string to construct.
+     * @param wordBank An iterable collection of substrings that can be used to construct the target.
+     * @return A list of lists, where each inner list represents one possible
+     *         way of constructing the target string using the given word bank.
+     */
+    public static List<List<String>> allConstruct(String target, Iterable<String> wordBank) {
+        List<List<List<String>>> table = new ArrayList<>(target.length() + 1);
+
+        for (int i = 0; i <= target.length(); i++) {
+            table.add(new ArrayList<>());
+        }
+
+        table.get(0).add(new ArrayList<>());
+
+        for (int i = 0; i <= target.length(); i++) {
+            if (!table.get(i).isEmpty()) {
+                for (String word : wordBank) {
+                    if (i + word.length() <= target.length() && target.substring(i, i + word.length()).equals(word)) {
+
+                        List<List<String>> newCombinations = new ArrayList<>();
+                        for (List<String> combination : table.get(i)) {
+                            List<String> newCombination = new ArrayList<>(combination);
+                            newCombination.add(word);
+                            newCombinations.add(newCombination);
+                        }
+
+                        table.get(i + word.length()).addAll(newCombinations);
+                    }
+                }
+            }
+        }
+
+        return table.get(target.length());
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java
new file mode 100644
index 000000000000..4979327fbf2c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java
@@ -0,0 +1,38 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class AllConstructTest {
+
+    @Test
+    public void testAllConstructBasic() {
+        List<List<String>> expected = Arrays.asList(Arrays.asList("he", "l", "l", "o"));
+        List<List<String>> result = AllConstruct.allConstruct("hello", Arrays.asList("he", "l", "o"));
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testAllConstructMultipleWays() {
+        List<List<String>> expected = Arrays.asList(Arrays.asList("purp", "le"), Arrays.asList("p", "ur", "p", "le"));
+        List<List<String>> result = AllConstruct.allConstruct("purple", Arrays.asList("purp", "p", "ur", "le", "purpl"));
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testAllConstructNoWays() {
+        List<List<String>> expected = Arrays.asList();
+        List<List<String>> result = AllConstruct.allConstruct("abcdef", Arrays.asList("gh", "ijk"));
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testAllConstructEmptyTarget() {
+        List<List<String>> expected = Arrays.asList(Arrays.asList());
+        List<List<String>> result = AllConstruct.allConstruct("", Arrays.asList("a", "b", "c"));
+        assertEquals(expected, result);
+    }
+}

From 3de202b953c69351fff9d43a2e862ce39c5b934f Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 20:16:02 +0530
Subject: [PATCH 0667/1338] Enhance docs, add more tests in `ADFGVXCipher`
 (#5897)

---
 .../thealgorithms/ciphers/ADFGVXCipher.java   | 82 ++++++++++++++-----
 .../ciphers/ADFGVXCipherTest.java             | 44 ++++++----
 2 files changed, 90 insertions(+), 36 deletions(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java b/src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java
index 3e62d6a26dcb..d915858f9e6f 100644
--- a/src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java
@@ -3,23 +3,38 @@
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
+
 /**
- * The ADFGVX cipher is a historically significant cipher used by
- * the German Army during World War I. It is a fractionating transposition
- * cipher that combines a Polybius square substitution with a columnar
- * transposition. It's named after the six letters (A, D, F, G, V, X)
- * that it uses in its substitution process.
- * https://en.wikipedia.org/wiki/ADFGVX_cipher
+ * The ADFGVX cipher is a fractionating transposition cipher that was used by
+ * the German Army during World War I. It combines a **Polybius square substitution**
+ * with a **columnar transposition** to enhance encryption strength.
+ * <p>
+ * The name "ADFGVX" refers to the six letters (A, D, F, G, V, X) used as row and
+ * column labels in the Polybius square. This cipher was designed to secure
+ * communication and create complex, hard-to-break ciphertexts.
+ * <p>
+ * Learn more: <a href="https://en.wikipedia.org/wiki/ADFGVX_cipher">ADFGVX Cipher - Wikipedia</a>.
+ * <p>
+ * Example usage:
+ * <pre>
+ * ADFGVXCipher cipher = new ADFGVXCipher();
+ * String encrypted = cipher.encrypt("attack at 1200am", "PRIVACY");
+ * String decrypted = cipher.decrypt(encrypted, "PRIVACY");
+ * </pre>
  *
  * @author bennybebo
  */
 public class ADFGVXCipher {
 
+    // Constants used in the Polybius square
     private static final char[] POLYBIUS_LETTERS = {'A', 'D', 'F', 'G', 'V', 'X'};
     private static final char[][] POLYBIUS_SQUARE = {{'N', 'A', '1', 'C', '3', 'H'}, {'8', 'T', 'B', '2', 'O', 'M'}, {'E', '5', 'W', 'R', 'P', 'D'}, {'4', 'F', '6', 'G', '7', 'I'}, {'9', 'J', '0', 'K', 'L', 'Q'}, {'S', 'U', 'V', 'X', 'Y', 'Z'}};
+
+    // Maps for fast substitution lookups
     private static final Map<String, Character> POLYBIUS_MAP = new HashMap<>();
     private static final Map<Character, String> REVERSE_POLYBIUS_MAP = new HashMap<>();
 
+    // Static block to initialize the lookup tables from the Polybius square
     static {
         for (int i = 0; i < POLYBIUS_SQUARE.length; i++) {
             for (int j = 0; j < POLYBIUS_SQUARE[i].length; j++) {
@@ -30,26 +45,41 @@ public class ADFGVXCipher {
         }
     }
 
-    // Encrypts the plaintext using the ADFGVX cipher
+    /**
+     * Encrypts a given plaintext using the ADFGVX cipher with the provided keyword.
+     * Steps:
+     * 1. Substitute each letter in the plaintext with a pair of ADFGVX letters.
+     * 2. Perform a columnar transposition on the fractionated text using the keyword.
+     *
+     * @param plaintext The message to be encrypted (can contain letters and digits).
+     * @param key       The keyword for columnar transposition.
+     * @return The encrypted message as ciphertext.
+     */
     public String encrypt(String plaintext, String key) {
-        plaintext = plaintext.toUpperCase().replaceAll("[^A-Z0-9]", "");
+        plaintext = plaintext.toUpperCase().replaceAll("[^A-Z0-9]", ""); // Sanitize input
         StringBuilder fractionatedText = new StringBuilder();
 
-        // Step 1: Polybius square substitution
         for (char c : plaintext.toCharArray()) {
             fractionatedText.append(REVERSE_POLYBIUS_MAP.get(c));
         }
 
-        // Step 2: Columnar transposition
         return columnarTransposition(fractionatedText.toString(), key);
     }
 
-    // Decrypts the ciphertext using the ADFGVX cipher
+    /**
+     * Decrypts a given ciphertext using the ADFGVX cipher with the provided keyword.
+     * Steps:
+     * 1. Reverse the columnar transposition performed during encryption.
+     * 2. Substitute each pair of ADFGVX letters with the corresponding plaintext letter.
+     * The resulting text is the decrypted message.
+     *
+     * @param ciphertext The encrypted message.
+     * @param key        The keyword used during encryption.
+     * @return The decrypted plaintext message.
+     */
     public String decrypt(String ciphertext, String key) {
-        // Step 1: Reverse the columnar transposition
         String fractionatedText = reverseColumnarTransposition(ciphertext, key);
 
-        // Step 2: Polybius square substitution
         StringBuilder plaintext = new StringBuilder();
         for (int i = 0; i < fractionatedText.length(); i += 2) {
             String pair = fractionatedText.substring(i, i + 2);
@@ -59,14 +89,21 @@ public String decrypt(String ciphertext, String key) {
         return plaintext.toString();
     }
 
+    /**
+     * Helper method: Performs columnar transposition during encryption
+     *
+     * @param text The fractionated text to be transposed
+     * @param key  The keyword for columnar transposition
+     * @return The transposed text
+     */
     private String columnarTransposition(String text, String key) {
         int numRows = (int) Math.ceil((double) text.length() / key.length());
         char[][] table = new char[numRows][key.length()];
-        for (char[] row : table) {
-            Arrays.fill(row, '_'); // Fill with underscores to handle empty cells
+        for (char[] row : table) { // Fill empty cells with underscores
+            Arrays.fill(row, '_');
         }
 
-        // Fill the table row by row
+        // Populate the table row by row
         for (int i = 0; i < text.length(); i++) {
             table[i / key.length()][i % key.length()] = text.charAt(i);
         }
@@ -88,6 +125,13 @@ private String columnarTransposition(String text, String key) {
         return ciphertext.toString();
     }
 
+    /**
+     * Helper method: Reverses the columnar transposition during decryption
+     *
+     * @param ciphertext The transposed text to be reversed
+     * @param key        The keyword used during encryption
+     * @return The reversed text
+     */
     private String reverseColumnarTransposition(String ciphertext, String key) {
         int numRows = (int) Math.ceil((double) ciphertext.length() / key.length());
         char[][] table = new char[numRows][key.length()];
@@ -96,19 +140,19 @@ private String reverseColumnarTransposition(String ciphertext, String key) {
         Arrays.sort(sortedKey);
 
         int index = 0;
-        // Fill the table column by column according to the sorted key order
+        // Populate the table column by column according to the sorted key
         for (char keyChar : sortedKey) {
             int column = key.indexOf(keyChar);
             for (int row = 0; row < numRows; row++) {
                 if (index < ciphertext.length()) {
                     table[row][column] = ciphertext.charAt(index++);
                 } else {
-                    table[row][column] = '_'; // Fill empty cells with an underscore
+                    table[row][column] = '_';
                 }
             }
         }
 
-        // Read the table row by row to get the fractionated text
+        // Read the table row by row to reconstruct the fractionated text
         StringBuilder fractionatedText = new StringBuilder();
         for (char[] row : table) {
             for (char cell : row) {
diff --git a/src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java b/src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java
index a1fc4fd9ebe5..4db856e40b84 100644
--- a/src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java
@@ -6,31 +6,41 @@
 
 class ADFGVXCipherTest {
 
-    ADFGVXCipher adfgvxCipher = new ADFGVXCipher();
+    private final ADFGVXCipher adfgvxCipher = new ADFGVXCipher();
 
     @Test
-    void adfgvxCipherEncryptTest() {
-        // given
-        String message = "attack at 1200am"; // Plaintext message
-        String keyword = "PRIVACY";
+    void testEncrypt() {
+        String message = "attack at 1200am";
+        String key = "PRIVACY";
 
-        // when
-        String cipherText = adfgvxCipher.encrypt(message, keyword);
+        String encrypted = adfgvxCipher.encrypt(message, key);
+        assertEquals("DGDDDAGDDGAFADDFDADVDVFAADVX", encrypted);
+    }
+
+    @Test
+    void testDecrypt() {
+        String encrypted = "DGDDDAGDDGAFADDFDADVDVFAADVX";
+        String key = "PRIVACY";
 
-        // then
-        assertEquals("DGDDDAGDDGAFADDFDADVDVFAADVX", cipherText);
+        String decrypted = adfgvxCipher.decrypt(encrypted, key);
+        assertEquals("ATTACKAT1200AM", decrypted);
     }
 
     @Test
-    void adfgvxCipherDecryptTest() {
-        // given
-        String cipherText = "DGDDDAGDDGAFADDFDADVDVFAADVX"; // Ciphertext message
-        String keyword = "PRIVACY";
+    void testEmptyInput() {
+        String encrypted = adfgvxCipher.encrypt("", "PRIVACY");
+        String decrypted = adfgvxCipher.decrypt("", "PRIVACY");
+        assertEquals("", encrypted);
+        assertEquals("", decrypted);
+    }
 
-        // when
-        String plainText = adfgvxCipher.decrypt(cipherText, keyword);
+    @Test
+    void testShortKey() {
+        String message = "TESTING";
+        String key = "A";
 
-        // then
-        assertEquals("ATTACKAT1200AM", plainText);
+        String encrypted = adfgvxCipher.encrypt(message, key);
+        String decrypted = adfgvxCipher.decrypt(encrypted, key);
+        assertEquals("TESTING", decrypted);
     }
 }

From 4d85c61c375eacfd30e4f523ee267866e5f49fa3 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 20:20:32 +0530
Subject: [PATCH 0668/1338] Enhance docs, add more tests in `RSA` (#5898)

---
 .../java/com/thealgorithms/ciphers/RSA.java   | 79 ++++++++++++++++---
 .../com/thealgorithms/ciphers/RSATest.java    | 59 +++++++++++---
 2 files changed, 116 insertions(+), 22 deletions(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/RSA.java b/src/main/java/com/thealgorithms/ciphers/RSA.java
index f50e501e68c8..28af1a62032a 100644
--- a/src/main/java/com/thealgorithms/ciphers/RSA.java
+++ b/src/main/java/com/thealgorithms/ciphers/RSA.java
@@ -4,7 +4,27 @@
 import java.security.SecureRandom;
 
 /**
- * @author Nguyen Duy Tiep on 23-Oct-17.
+ * RSA is an asymmetric cryptographic algorithm used for secure data encryption and decryption.
+ * It relies on a pair of keys: a public key (used for encryption) and a private key
+ * (used for decryption). The algorithm is based on the difficulty of factoring large prime numbers.
+ *
+ * This implementation includes key generation, encryption, and decryption methods that can handle both
+ * text-based messages and BigInteger inputs. For more details on RSA:
+ * <a href="https://en.wikipedia.org/wiki/RSA_(cryptosystem)">RSA Cryptosystem - Wikipedia</a>.
+ *
+ * Example Usage:
+ * <pre>
+ * RSA rsa = new RSA(1024);
+ * String encryptedMessage = rsa.encrypt("Hello RSA!");
+ * String decryptedMessage = rsa.decrypt(encryptedMessage);
+ * System.out.println(decryptedMessage);  // Output: Hello RSA!
+ * </pre>
+ *
+ * Note: The key size directly affects the security and performance of the RSA algorithm.
+ * Larger keys are more secure but slower to compute.
+ *
+ * @author Nguyen Duy Tiep
+ * @version 23-Oct-17
  */
 public class RSA {
 
@@ -12,55 +32,88 @@ public class RSA {
     private BigInteger privateKey;
     private BigInteger publicKey;
 
+    /**
+     * Constructor that generates RSA keys with the specified number of bits.
+     *
+     * @param bits The bit length of the keys to be generated. Common sizes include 512, 1024, 2048, etc.
+     */
     public RSA(int bits) {
         generateKeys(bits);
     }
 
     /**
-     * @return encrypted message
+     * Encrypts a text message using the RSA public key.
+     *
+     * @param message The plaintext message to be encrypted.
+     * @throws IllegalArgumentException If the message is empty.
+     * @return The encrypted message represented as a String.
      */
     public synchronized String encrypt(String message) {
+        if (message.isEmpty()) {
+            throw new IllegalArgumentException("Message is empty");
+        }
         return (new BigInteger(message.getBytes())).modPow(publicKey, modulus).toString();
     }
 
     /**
-     * @return encrypted message as big integer
+     * Encrypts a BigInteger message using the RSA public key.
+     *
+     * @param message The plaintext message as a BigInteger.
+     * @return The encrypted message as a BigInteger.
      */
     public synchronized BigInteger encrypt(BigInteger message) {
         return message.modPow(publicKey, modulus);
     }
 
     /**
-     * @return plain message
+     * Decrypts an encrypted message (as String) using the RSA private key.
+     *
+     * @param encryptedMessage The encrypted message to be decrypted, represented as a String.
+     * @throws IllegalArgumentException If the message is empty.
+     * @return The decrypted plaintext message as a String.
      */
     public synchronized String decrypt(String encryptedMessage) {
+        if (encryptedMessage.isEmpty()) {
+            throw new IllegalArgumentException("Message is empty");
+        }
         return new String((new BigInteger(encryptedMessage)).modPow(privateKey, modulus).toByteArray());
     }
 
     /**
-     * @return plain message as big integer
+     * Decrypts an encrypted BigInteger message using the RSA private key.
+     *
+     * @param encryptedMessage The encrypted message as a BigInteger.
+     * @return The decrypted plaintext message as a BigInteger.
      */
     public synchronized BigInteger decrypt(BigInteger encryptedMessage) {
         return encryptedMessage.modPow(privateKey, modulus);
     }
 
     /**
-     * Generate a new public and private key set.
+     * Generates a new RSA key pair (public and private keys) with the specified bit length.
+     * Steps:
+     * 1. Generate two large prime numbers p and q.
+     * 2. Compute the modulus n = p * q.
+     * 3. Compute Euler's totient function: φ(n) = (p-1) * (q-1).
+     * 4. Choose a public key e (starting from 3) that is coprime with φ(n).
+     * 5. Compute the private key d as the modular inverse of e mod φ(n).
+     * The public key is (e, n) and the private key is (d, n).
+     *
+     * @param bits The bit length of the keys to be generated.
      */
     public final synchronized void generateKeys(int bits) {
-        SecureRandom r = new SecureRandom();
-        BigInteger p = new BigInteger(bits / 2, 100, r);
-        BigInteger q = new BigInteger(bits / 2, 100, r);
+        SecureRandom random = new SecureRandom();
+        BigInteger p = new BigInteger(bits / 2, 100, random);
+        BigInteger q = new BigInteger(bits / 2, 100, random);
         modulus = p.multiply(q);
 
-        BigInteger m = (p.subtract(BigInteger.ONE)).multiply(q.subtract(BigInteger.ONE));
+        BigInteger phi = (p.subtract(BigInteger.ONE)).multiply(q.subtract(BigInteger.ONE));
 
         publicKey = BigInteger.valueOf(3L);
-
-        while (m.gcd(publicKey).intValue() > 1) {
+        while (phi.gcd(publicKey).intValue() > 1) {
             publicKey = publicKey.add(BigInteger.TWO);
         }
 
-        privateKey = publicKey.modInverse(m);
+        privateKey = publicKey.modInverse(phi);
     }
 }
diff --git a/src/test/java/com/thealgorithms/ciphers/RSATest.java b/src/test/java/com/thealgorithms/ciphers/RSATest.java
index c82f68d11f4c..577f56426be8 100644
--- a/src/test/java/com/thealgorithms/ciphers/RSATest.java
+++ b/src/test/java/com/thealgorithms/ciphers/RSATest.java
@@ -1,23 +1,64 @@
 package com.thealgorithms.ciphers;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.math.BigInteger;
 import org.junit.jupiter.api.Test;
 
 class RSATest {
 
-    RSA rsa = new RSA(1024);
+    private final RSA rsa = new RSA(1024);
 
     @Test
-    void testRSA() {
-        // given
-        String textToEncrypt = "Such secure";
+    void testEncryptDecryptString() {
+        String originalMessage = "Such secure";
+        String encryptedMessage = rsa.encrypt(originalMessage);
+        String decryptedMessage = rsa.decrypt(encryptedMessage);
+        assertEquals(originalMessage, decryptedMessage);
+    }
+
+    @Test
+    void testEncryptDecryptBigInteger() {
+        BigInteger originalMessage = new BigInteger("12345678901234567890");
+        BigInteger encryptedMessage = rsa.encrypt(originalMessage);
+        BigInteger decryptedMessage = rsa.decrypt(encryptedMessage);
+        assertEquals(originalMessage, decryptedMessage);
+    }
 
-        // when
-        String cipherText = rsa.encrypt(textToEncrypt);
-        String decryptedText = rsa.decrypt(cipherText);
+    @Test
+    void testEmptyMessage() {
+        String originalMessage = "";
+        assertThrows(IllegalArgumentException.class, () -> rsa.encrypt(originalMessage));
+        assertThrows(IllegalArgumentException.class, () -> rsa.decrypt(originalMessage));
+    }
+
+    @Test
+    void testDifferentKeySizes() {
+        // Testing with 512-bit RSA keys
+        RSA smallRSA = new RSA(512);
+        String originalMessage = "Test with smaller key";
 
-        // then
-        assertEquals("Such secure", decryptedText);
+        String encryptedMessage = smallRSA.encrypt(originalMessage);
+        String decryptedMessage = smallRSA.decrypt(encryptedMessage);
+
+        assertEquals(originalMessage, decryptedMessage);
+
+        // Testing with 2048-bit RSA keys
+        RSA largeRSA = new RSA(2048);
+        String largeOriginalMessage = "Test with larger key";
+
+        String largeEncryptedMessage = largeRSA.encrypt(largeOriginalMessage);
+        String largeDecryptedMessage = largeRSA.decrypt(largeEncryptedMessage);
+
+        assertEquals(largeOriginalMessage, largeDecryptedMessage);
+    }
+
+    @Test
+    void testSpecialCharacters() {
+        String originalMessage = "Hello, RSA! @2024#";
+        String encryptedMessage = rsa.encrypt(originalMessage);
+        String decryptedMessage = rsa.decrypt(encryptedMessage);
+        assertEquals(originalMessage, decryptedMessage);
     }
 }

From 03777f8d889464c8a199539dda5b28a2e30a2c27 Mon Sep 17 00:00:00 2001
From: Rashi Dashore <119104356+rashi07dashore@users.noreply.github.com>
Date: Sat, 26 Oct 2024 20:24:53 +0530
Subject: [PATCH 0669/1338] Add MinSumKSizeSubarray algorithm (#6025)

---
 .../slidingwindow/MinSumKSizeSubarray.java    | 51 ++++++++++++
 .../MinSumKSizeSubarrayTest.java              | 79 +++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java
 create mode 100644 src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java

diff --git a/src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java b/src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java
new file mode 100644
index 000000000000..40a5441fa7a0
--- /dev/null
+++ b/src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java
@@ -0,0 +1,51 @@
+package com.thealgorithms.slidingwindow;
+/**
+ * The Sliding Window algorithm is used to find the minimum sum of a subarray
+ * of a fixed size k within a given array.
+ *
+ * <p>
+ * Worst-case performance O(n)
+ * Best-case performance O(n)
+ * Average performance O(n)
+ * Worst-case space complexity O(1)
+ *
+ * This class provides a static method to find the minimum sum of a subarray
+ * with a specified length k.
+ *
+ * @author Rashi Dashore (https://github.com/rashi07dashore)
+ */
+public final class MinSumKSizeSubarray {
+
+    // Prevent instantiation
+    private MinSumKSizeSubarray() {
+    }
+
+    /**
+     * This method finds the minimum sum of a subarray of a given size k.
+     *
+     * @param arr is the input array where the minimum sum needs to be found
+     * @param k   is the size of the subarray
+     * @return the minimum sum of the subarray of size k
+     */
+    public static int minSumKSizeSubarray(int[] arr, int k) {
+        if (arr.length < k) {
+            return -1; // Edge case: not enough elements
+        }
+
+        int minSum;
+        int windowSum = 0;
+
+        // Calculate the sum of the first window
+        for (int i = 0; i < k; i++) {
+            windowSum += arr[i];
+        }
+        minSum = windowSum;
+
+        // Slide the window across the array
+        for (int i = k; i < arr.length; i++) {
+            windowSum += arr[i] - arr[i - k];
+            minSum = Math.min(minSum, windowSum);
+        }
+        return minSum;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java b/src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java
new file mode 100644
index 000000000000..4656c8baf327
--- /dev/null
+++ b/src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java
@@ -0,0 +1,79 @@
+package com.thealgorithms.slidingwindow;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the MinSumKSizeSubarray class.
+ *
+ * @author Rashi Dashore (https://github.com/rashi07dashore)
+ */
+class MinSumKSizeSubarrayTest {
+
+    /**
+     * Test for the basic case of finding the minimum sum.
+     */
+    @Test
+    void testMinSumKSizeSubarray() {
+        int[] arr = {2, 1, 5, 1, 3, 2};
+        int k = 3;
+        int expectedMinSum = 6; // Corrected: Minimum sum of a subarray of size 3
+        assertEquals(expectedMinSum, MinSumKSizeSubarray.minSumKSizeSubarray(arr, k));
+    }
+
+    /**
+     * Test for a different array and subarray size.
+     */
+    @Test
+    void testMinSumKSizeSubarrayWithDifferentValues() {
+        int[] arr = {1, 2, 3, 4, 5};
+        int k = 2;
+        int expectedMinSum = 3; // 1 + 2
+        assertEquals(expectedMinSum, MinSumKSizeSubarray.minSumKSizeSubarray(arr, k));
+    }
+
+    /**
+     * Test for edge case with insufficient elements.
+     */
+    @Test
+    void testMinSumKSizeSubarrayWithInsufficientElements() {
+        int[] arr = {1, 2};
+        int k = 3; // Not enough elements
+        int expectedMinSum = -1; // Edge case
+        assertEquals(expectedMinSum, MinSumKSizeSubarray.minSumKSizeSubarray(arr, k));
+    }
+
+    /**
+     * Test for large array.
+     */
+    @Test
+    void testMinSumKSizeSubarrayWithLargeArray() {
+        int[] arr = {5, 4, 3, 2, 1, 0, -1, -2, -3, -4};
+        int k = 5;
+        int expectedMinSum = -10; // -1 + -2 + -3 + -4 + 0
+        assertEquals(expectedMinSum, MinSumKSizeSubarray.minSumKSizeSubarray(arr, k));
+    }
+
+    /**
+     * Test for array with negative numbers.
+     */
+    @Test
+    void testMinSumKSizeSubarrayWithNegativeNumbers() {
+        int[] arr = {-1, -2, -3, -4, -5};
+        int k = 2;
+        int expectedMinSum = -9; // -4 + -5
+        assertEquals(expectedMinSum, MinSumKSizeSubarray.minSumKSizeSubarray(arr, k));
+    }
+
+    /**
+     * Test for the case where k equals the array length.
+     */
+    @Test
+    void testMinSumKSizeSubarrayWithKEqualToArrayLength() {
+        int[] arr = {1, 2, 3, 4, 5};
+        int k = 5;
+        int expectedMinSum = 15; // 1 + 2 + 3 + 4 + 5
+        assertEquals(expectedMinSum, MinSumKSizeSubarray.minSumKSizeSubarray(arr, k));
+    }
+}

From 4e460021039e3c6ba5e5888893bc2147242d86fe Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 20:37:47 +0530
Subject: [PATCH 0670/1338] Enhance docs, add more tests in `XORCipher` (#5900)

---
 DIRECTORY.md                                  |  2 +
 .../com/thealgorithms/ciphers/XORCipher.java  | 58 +++++++++++++-
 .../thealgorithms/ciphers/XORCipherTest.java  | 77 +++++++++++++++----
 3 files changed, 122 insertions(+), 15 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 9ebbd484376b..2b47ae08ba4a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -597,6 +597,7 @@
           * slidingwindow
             * [LongestSubstringWithoutRepeatingCharacters](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java)
             * [MaxSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java)
+            * [MinSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java)
           * sorts
             * [AdaptiveMergeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java)
             * [BeadSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BeadSort.java)
@@ -1217,6 +1218,7 @@
           * slidingwindow
             * [LongestSubstringWithoutRepeatingCharactersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java)
             * [MaxSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java)
+            * [MinSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java)
           * sorts
             * [AdaptiveMergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java)
             * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
diff --git a/src/main/java/com/thealgorithms/ciphers/XORCipher.java b/src/main/java/com/thealgorithms/ciphers/XORCipher.java
index c4410d8c77ba..a612ccfbcdef 100644
--- a/src/main/java/com/thealgorithms/ciphers/XORCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/XORCipher.java
@@ -5,18 +5,46 @@
 import java.util.HexFormat;
 
 /**
- * A simple implementation of XOR cipher that, given a key, allows to encrypt and decrypt a plaintext.
+ * A simple implementation of the XOR cipher that allows both encryption and decryption
+ * using a given key. This cipher works by applying the XOR bitwise operation between
+ * the bytes of the input text and the corresponding bytes of the key (repeating the key
+ * if necessary).
  *
- * @author <a href="https://github.com/lcsjunior">lcsjunior</a>
+ * Usage:
+ * - Encryption: Converts plaintext into a hexadecimal-encoded ciphertext.
+ * - Decryption: Converts the hexadecimal ciphertext back into plaintext.
+ *
+ * Characteristics:
+ * - Symmetric: The same key is used for both encryption and decryption.
+ * - Simple but vulnerable: XOR encryption is insecure for real-world cryptography,
+ *   especially when the same key is reused.
+ *
+ * Example:
+ * Plaintext: "Hello!"
+ * Key: "key"
+ * Encrypted: "27090c03120b"
+ * Decrypted: "Hello!"
  *
+ * Reference: <a href="https://en.wikipedia.org/wiki/XOR_cipher">XOR Cipher - Wikipedia</a>
+ *
+ * @author <a href="https://github.com/lcsjunior">lcsjunior</a>
  */
 public final class XORCipher {
 
+    // Default character encoding for string conversion
     private static final Charset CS_DEFAULT = StandardCharsets.UTF_8;
 
     private XORCipher() {
     }
 
+    /**
+     * Applies the XOR operation between the input bytes and the key bytes.
+     * If the key is shorter than the input, it wraps around (cyclically).
+     *
+     * @param inputBytes The input byte array (plaintext or ciphertext).
+     * @param keyBytes The key byte array used for XOR operation.
+     * @return A new byte array containing the XOR result.
+     */
     public static byte[] xor(final byte[] inputBytes, final byte[] keyBytes) {
         byte[] outputBytes = new byte[inputBytes.length];
         for (int i = 0; i < inputBytes.length; ++i) {
@@ -25,14 +53,40 @@ public static byte[] xor(final byte[] inputBytes, final byte[] keyBytes) {
         return outputBytes;
     }
 
+    /**
+     * Encrypts the given plaintext using the XOR cipher with the specified key.
+     * The result is a hexadecimal-encoded string representing the ciphertext.
+     *
+     * @param plainText The input plaintext to encrypt.
+     * @param key The encryption key.
+     * @throws IllegalArgumentException if the key is empty.
+     * @return A hexadecimal string representing the encrypted text.
+     */
     public static String encrypt(final String plainText, final String key) {
+        if (key.isEmpty()) {
+            throw new IllegalArgumentException("Key must not be empty");
+        }
+
         byte[] plainTextBytes = plainText.getBytes(CS_DEFAULT);
         byte[] keyBytes = key.getBytes(CS_DEFAULT);
         byte[] xorResult = xor(plainTextBytes, keyBytes);
         return HexFormat.of().formatHex(xorResult);
     }
 
+    /**
+     * Decrypts the given ciphertext (in hexadecimal format) using the XOR cipher
+     * with the specified key. The result is the original plaintext.
+     *
+     * @param cipherText The hexadecimal string representing the encrypted text.
+     * @param key The decryption key (must be the same as the encryption key).
+     * @throws IllegalArgumentException if the key is empty.
+     * @return The decrypted plaintext.
+     */
     public static String decrypt(final String cipherText, final String key) {
+        if (key.isEmpty()) {
+            throw new IllegalArgumentException("Key must not be empty");
+        }
+
         byte[] cipherBytes = HexFormat.of().parseHex(cipherText);
         byte[] keyBytes = key.getBytes(CS_DEFAULT);
         byte[] xorResult = xor(cipherBytes, keyBytes);
diff --git a/src/test/java/com/thealgorithms/ciphers/XORCipherTest.java b/src/test/java/com/thealgorithms/ciphers/XORCipherTest.java
index 15e27d5d6778..fdfe640cc19b 100644
--- a/src/test/java/com/thealgorithms/ciphers/XORCipherTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/XORCipherTest.java
@@ -1,34 +1,85 @@
 package com.thealgorithms.ciphers;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
 class XORCipherTest {
 
     @Test
-    void xorEncryptTest() {
-        // given
+    void xorEncryptDecryptTest() {
         String plaintext = "My t&xt th@t will be ençrypted...";
         String key = "My ç&cret key!";
 
-        // when
         String cipherText = XORCipher.encrypt(plaintext, key);
+        String decryptedText = XORCipher.decrypt(cipherText, key);
 
-        // then
-        assertEquals("000000b7815e1752111c601f450e48211500a1c206061ca6d35212150d4429570eed", cipherText);
+        assertEquals("My t&xt th@t will be ençrypted...", decryptedText);
     }
 
     @Test
-    void xorDecryptTest() {
-        // given
-        String cipherText = "000000b7815e1752111c601f450e48211500a1c206061ca6d35212150d4429570eed";
-        String key = "My ç&cret key!";
+    void testEmptyPlaintext() {
+        String plaintext = "";
+        String key = "anykey";
+
+        String cipherText = XORCipher.encrypt(plaintext, key);
+        String decryptedText = XORCipher.decrypt(cipherText, key);
+
+        assertEquals("", cipherText);
+        assertEquals("", decryptedText);
+    }
+
+    @Test
+    void testEmptyKey() {
+        String plaintext = "Hello World!";
+        String key = "";
+
+        assertThrows(IllegalArgumentException.class, () -> XORCipher.encrypt(plaintext, key));
+        assertThrows(IllegalArgumentException.class, () -> XORCipher.decrypt(plaintext, key));
+    }
+
+    @Test
+    void testShortKey() {
+        String plaintext = "Short message";
+        String key = "k";
+
+        String cipherText = XORCipher.encrypt(plaintext, key);
+        String decryptedText = XORCipher.decrypt(cipherText, key);
+
+        assertEquals(plaintext, decryptedText);
+    }
 
-        // when
-        String plainText = XORCipher.decrypt(cipherText, key);
+    @Test
+    void testNonASCIICharacters() {
+        String plaintext = "こんにちは世界"; // "Hello World" in Japanese (Konichiwa Sekai)
+        String key = "key";
+
+        String cipherText = XORCipher.encrypt(plaintext, key);
+        String decryptedText = XORCipher.decrypt(cipherText, key);
+
+        assertEquals(plaintext, decryptedText);
+    }
+
+    @Test
+    void testSameKeyAndPlaintext() {
+        String plaintext = "samekey";
+        String key = "samekey";
+
+        String cipherText = XORCipher.encrypt(plaintext, key);
+        String decryptedText = XORCipher.decrypt(cipherText, key);
+
+        assertEquals(plaintext, decryptedText);
+    }
+
+    @Test
+    void testLongPlaintextShortKey() {
+        String plaintext = "This is a long plaintext message.";
+        String key = "key";
+
+        String cipherText = XORCipher.encrypt(plaintext, key);
+        String decryptedText = XORCipher.decrypt(cipherText, key);
 
-        // then
-        assertEquals("My t&xt th@t will be ençrypted...", plainText);
+        assertEquals(plaintext, decryptedText);
     }
 }

From 687d2518cce0c57aac753b4d2d210c62e9b393d9 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 20:41:34 +0530
Subject: [PATCH 0671/1338] Enhance docs, remove main, add tests in AnytoAny
 (#5916)

---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/conversions/AnytoAny.java   | 83 +++++++++++++------
 .../conversions/AnytoAnyTest.java             | 48 +++++++++++
 3 files changed, 107 insertions(+), 25 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/conversions/AnytoAnyTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 2b47ae08ba4a..bb952a26c6e9 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -789,6 +789,7 @@
           * conversions
             * [AffineConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/AffineConverterTest.java)
             * [AnyBaseToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java)
+            * [AnytoAnyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/AnytoAnyTest.java)
             * [BinaryToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java)
             * [BinaryToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java)
             * [BinaryToOctalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java)
diff --git a/src/main/java/com/thealgorithms/conversions/AnytoAny.java b/src/main/java/com/thealgorithms/conversions/AnytoAny.java
index 801e493032e0..e7bdbc2b79c4 100644
--- a/src/main/java/com/thealgorithms/conversions/AnytoAny.java
+++ b/src/main/java/com/thealgorithms/conversions/AnytoAny.java
@@ -1,35 +1,68 @@
 package com.thealgorithms.conversions;
 
-import java.util.Scanner;
-
-// given a source number , source base, destination base, this code can give you the destination
-// number.
-// sn ,sb,db ---> ()dn  .   this is what we have to do    .
-
+/**
+ * A utility class for converting numbers from any base to any other base.
+ *
+ * This class provides a method to convert a source number from a given base
+ * to a destination number in another base. Valid bases range from 2 to 10.
+ */
 public final class AnytoAny {
     private AnytoAny() {
     }
 
-    public static void main(String[] args) {
-        Scanner scn = new Scanner(System.in);
-        int sn = scn.nextInt();
-        int sb = scn.nextInt();
-        int db = scn.nextInt();
-        int m = 1;
-        int dec = 0;
-        int dn = 0;
-        while (sn != 0) {
-            dec = dec + (sn % 10) * m;
-            m *= sb;
-            sn /= 10;
+    /**
+     * Converts a number from a source base to a destination base.
+     *
+     * @param sourceNumber The number in the source base (as an integer).
+     * @param sourceBase The base of the source number (between 2 and 10).
+     * @param destBase The base to which the number should be converted (between 2 and 10).
+     * @throws IllegalArgumentException if the bases are not between 2 and 10.
+     * @return The converted number in the destination base (as an integer).
+     */
+    public static int convertBase(int sourceNumber, int sourceBase, int destBase) {
+        if (sourceBase < 2 || sourceBase > 10 || destBase < 2 || destBase > 10) {
+            throw new IllegalArgumentException("Bases must be between 2 and 10.");
+        }
+
+        int decimalValue = toDecimal(sourceNumber, sourceBase);
+        return fromDecimal(decimalValue, destBase);
+    }
+
+    /**
+     * Converts a number from a given base to its decimal representation (base 10).
+     *
+     * @param number The number in the original base.
+     * @param base The base of the given number.
+     * @return The decimal representation of the number.
+     */
+    private static int toDecimal(int number, int base) {
+        int decimalValue = 0;
+        int multiplier = 1;
+
+        while (number != 0) {
+            decimalValue += (number % 10) * multiplier;
+            multiplier *= base;
+            number /= 10;
         }
-        m = 1;
-        while (dec != 0) {
-            dn = dn + (dec % db) * m;
-            m *= 10;
-            dec /= db;
+        return decimalValue;
+    }
+
+    /**
+     * Converts a decimal (base 10) number to a specified base.
+     *
+     * @param decimal The decimal number to convert.
+     * @param base The destination base for conversion.
+     * @return The number in the specified base.
+     */
+    private static int fromDecimal(int decimal, int base) {
+        int result = 0;
+        int multiplier = 1;
+
+        while (decimal != 0) {
+            result += (decimal % base) * multiplier;
+            multiplier *= 10;
+            decimal /= base;
         }
-        System.out.println(dn);
-        scn.close();
+        return result;
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/AnytoAnyTest.java b/src/test/java/com/thealgorithms/conversions/AnytoAnyTest.java
new file mode 100644
index 000000000000..cdc012180bf9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/AnytoAnyTest.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class AnytoAnyTest {
+
+    @Test
+    void testValidConversions() {
+        assertEquals(101, AnytoAny.convertBase(5, 10, 2), "Decimal 5 should convert to binary 101");
+        assertEquals(2, AnytoAny.convertBase(2, 2, 10), "Binary 10 should convert to decimal 2");
+        assertEquals(6, AnytoAny.convertBase(110, 2, 8), "Binary 110 should convert to octal 6");
+        assertEquals(111, AnytoAny.convertBase(7, 10, 2), "Decimal 7 should convert to binary 111");
+    }
+
+    @Test
+    void testDecimalToBinary() {
+        assertEquals(1101, AnytoAny.convertBase(13, 10, 2), "Decimal 13 should convert to binary 1101");
+        assertEquals(0, AnytoAny.convertBase(0, 10, 2), "Decimal 0 should convert to binary 0");
+    }
+
+    @Test
+    void testBinaryToDecimal() {
+        assertEquals(13, AnytoAny.convertBase(1101, 2, 10), "Binary 1101 should convert to decimal 13");
+        assertEquals(0, AnytoAny.convertBase(0, 2, 10), "Binary 0 should convert to decimal 0");
+    }
+
+    @Test
+    void testOctalToDecimal() {
+        assertEquals(8, AnytoAny.convertBase(10, 8, 10), "Octal 10 should convert to decimal 8");
+        assertEquals(65, AnytoAny.convertBase(101, 8, 10), "Octal 101 should convert to decimal 65");
+    }
+
+    @Test
+    void testInvalidBases() {
+        assertThrows(IllegalArgumentException.class, () -> AnytoAny.convertBase(5, 1, 10), "Source base less than 2 should throw IllegalArgumentException");
+
+        assertThrows(IllegalArgumentException.class, () -> AnytoAny.convertBase(5, 10, 11), "Destination base greater than 10 should throw IllegalArgumentException");
+    }
+
+    @Test
+    void testLargeNumberConversion() {
+        assertEquals(1111101000, AnytoAny.convertBase(1000, 10, 2), "Decimal 1000 should convert to binary 1111101000");
+        assertEquals(1750, AnytoAny.convertBase(1000, 10, 8), "Decimal 1000 should convert to octal 1750");
+    }
+}

From 709d9771e24c5a178c24fe81e7e30a10f98e009a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 20:53:50 +0530
Subject: [PATCH 0672/1338] Add `GenerateSubsets` algorithm (#5867)

---
 DIRECTORY.md                                  |  2 +
 .../bitmanipulation/GenerateSubsets.java      | 44 ++++++++++++++++
 .../bitmanipulation/GenerateSubsetsTest.java  | 52 +++++++++++++++++++
 3 files changed, 98 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/GenerateSubsets.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index bb952a26c6e9..cd511b4ac61d 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -32,6 +32,7 @@
             * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
             * [FindNthBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/FindNthBit.java)
             * [FirstDifferentBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/FirstDifferentBit.java)
+            * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GenerateSubsets.java)
             * [GrayCodeConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java)
             * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java)
             * [HigherLowerPowerOfTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java)
@@ -738,6 +739,7 @@
             * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
             * [FindNthBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/FindNthBitTest.java)
             * [FirstDifferentBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/FirstDifferentBitTest.java)
+            * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java)
             * [GrayCodeConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java)
             * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java)
             * [HigherLowerPowerOfTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java)
diff --git a/src/main/java/com/thealgorithms/bitmanipulation/GenerateSubsets.java b/src/main/java/com/thealgorithms/bitmanipulation/GenerateSubsets.java
new file mode 100644
index 000000000000..f1b812495c1b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/GenerateSubsets.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.bitmanipulation;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * This class provides a method to generate all subsets (power set)
+ * of a given set using bit manipulation.
+ *
+ * @author Hardvan
+ */
+public final class GenerateSubsets {
+    private GenerateSubsets() {
+    }
+
+    /**
+     * Generates all subsets of a given set using bit manipulation.
+     * Steps:
+     * 1. Iterate over all numbers from 0 to 2^n - 1.
+     * 2. For each number, iterate over all bits from 0 to n - 1.
+     * 3. If the i-th bit of the number is set, add the i-th element of the set to the current subset.
+     * 4. Add the current subset to the list of subsets.
+     * 5. Return the list of subsets.
+     *
+     * @param set the input set of integers
+     * @return a list of all subsets represented as lists of integers
+     */
+    public static List<List<Integer>> generateSubsets(int[] set) {
+        int n = set.length;
+        List<List<Integer>> subsets = new ArrayList<>();
+
+        for (int mask = 0; mask < (1 << n); mask++) {
+            List<Integer> subset = new ArrayList<>();
+            for (int i = 0; i < n; i++) {
+                if ((mask & (1 << i)) != 0) {
+                    subset.add(set[i]);
+                }
+            }
+            subsets.add(subset);
+        }
+
+        return subsets;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java
new file mode 100644
index 000000000000..e3205d1d0dba
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java
@@ -0,0 +1,52 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class GenerateSubsetsTest {
+
+    @Test
+    void testGenerateSubsetsWithTwoElements() {
+        int[] set = {1, 2};
+        List<List<Integer>> expected = new ArrayList<>();
+        expected.add(new ArrayList<>());
+        expected.add(Arrays.asList(1));
+        expected.add(Arrays.asList(2));
+        expected.add(Arrays.asList(1, 2));
+
+        List<List<Integer>> result = GenerateSubsets.generateSubsets(set);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testGenerateSubsetsWithOneElement() {
+        int[] set = {3};
+        List<List<Integer>> expected = new ArrayList<>();
+        expected.add(new ArrayList<>());
+        expected.add(Arrays.asList(3));
+
+        List<List<Integer>> result = GenerateSubsets.generateSubsets(set);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testGenerateSubsetsWithThreeElements() {
+        int[] set = {4, 5, 6};
+        List<List<Integer>> expected = new ArrayList<>();
+        expected.add(new ArrayList<>());
+        expected.add(Arrays.asList(4));
+        expected.add(Arrays.asList(5));
+        expected.add(Arrays.asList(4, 5));
+        expected.add(Arrays.asList(6));
+        expected.add(Arrays.asList(4, 6));
+        expected.add(Arrays.asList(5, 6));
+        expected.add(Arrays.asList(4, 5, 6));
+
+        List<List<Integer>> result = GenerateSubsets.generateSubsets(set);
+        assertEquals(expected, result);
+    }
+}

From 20239f20f1f7194df4c1b34a55505fde53fc1f52 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 20:58:55 +0530
Subject: [PATCH 0673/1338] Enhance docs, add tests in `LeftistHeap` (#5982)

---
 .../datastructures/heaps/LeftistHeap.java     | 89 +++++++++++++------
 .../datastructures/heaps/LeftistHeapTest.java | 81 ++++++++++++++---
 2 files changed, 133 insertions(+), 37 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
index ca18673c6724..1c91d24f0fb5 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java
@@ -2,24 +2,33 @@
 
 import java.util.ArrayList;
 
-/*
- * This is a leftist heap that follows the same operations as a
- * binary min heap, but may be unbalanced at times and follows a
- * leftist property, in which the left side is more heavy on the
- * right based on the null-path length (npl) values.
+/**
+ * This class implements a Leftist Heap, which is a type of priority queue
+ * that follows similar operations to a binary min-heap but allows for
+ * unbalanced structures based on the leftist property.
  *
- * Source: https://iq.opengenus.org/leftist-heap/
+ * <p>
+ * A Leftist Heap maintains the leftist property, which ensures that the
+ * left subtree is heavier than the right subtree based on the
+ * null-path length (npl) values. This allows for efficient merging
+ * of heaps and supports operations like insertion, extraction of
+ * the minimum element, and in-order traversal.
+ * </p>
  *
+ * <p>
+ * For more information on Leftist Heaps, visit:
+ * <a href="https://iq.opengenus.org/leftist-heap/">OpenGenus</a>
+ * </p>
  */
-
 public class LeftistHeap {
+    // Node class representing each element in the Leftist Heap
     private static final class Node {
         private final int element;
         private int npl;
         private Node left;
         private Node right;
 
-        // Node constructor setting the data element and left/right pointers to null
+        // Node constructor that initializes the element and sets child pointers to null
         private Node(int element) {
             this.element = element;
             left = null;
@@ -30,31 +39,45 @@ private Node(int element) {
 
     private Node root;
 
-    // Constructor
+    // Constructor initializing an empty Leftist Heap
     public LeftistHeap() {
         root = null;
     }
 
-    // Checks if heap is empty
+    /**
+     * Checks if the heap is empty.
+     *
+     * @return true if the heap is empty; false otherwise
+     */
     public boolean isEmpty() {
         return root == null;
     }
 
-    // Resets structure to initial state
+    /**
+     * Resets the heap to its initial state, effectively clearing all elements.
+     */
     public void clear() {
-        // We will put head is null
-        root = null;
+        root = null; // Set root to null to clear the heap
     }
 
-    // Merge function that merges the contents of another leftist heap with the
-    // current one
+    /**
+     * Merges the contents of another Leftist Heap into this one.
+     *
+     * @param h1 the LeftistHeap to be merged into this heap
+     */
     public void merge(LeftistHeap h1) {
-        // If the present function is rhs then we ignore the merge
+        // Merge the current heap with the provided heap and set the provided heap's root to null
         root = merge(root, h1.root);
         h1.root = null;
     }
 
-    // Function merge with two Nodes a and b
+    /**
+     * Merges two nodes, maintaining the leftist property.
+     *
+     * @param a the first node
+     * @param b the second node
+     * @return the merged node maintaining the leftist property
+     */
     public Node merge(Node a, Node b) {
         if (a == null) {
             return b;
@@ -64,17 +87,17 @@ public Node merge(Node a, Node b) {
             return a;
         }
 
-        // Violates leftist property, so must do a swap
+        // Ensure that the leftist property is maintained
         if (a.element > b.element) {
             Node temp = a;
             a = b;
             b = temp;
         }
 
-        // Now we call the function merge to merge a and b
+        // Merge the right child of node a with node b
         a.right = merge(a.right, b);
 
-        // Violates leftist property so must swap here
+        // If left child is null, make right child the left child
         if (a.left == null) {
             a.left = a.right;
             a.right = null;
@@ -89,14 +112,21 @@ public Node merge(Node a, Node b) {
         return a;
     }
 
-    // Function insert. Uses the merge function to add the data
+    /**
+     * Inserts a new element into the Leftist Heap.
+     *
+     * @param a the element to be inserted
+     */
     public void insert(int a) {
         root = merge(new Node(a), root);
     }
 
-    // Returns and removes the minimum element in the heap
+    /**
+     * Extracts and removes the minimum element from the heap.
+     *
+     * @return the minimum element in the heap, or -1 if the heap is empty
+     */
     public int extractMin() {
-        // If is empty return -1
         if (isEmpty()) {
             return -1;
         }
@@ -106,14 +136,23 @@ public int extractMin() {
         return min;
     }
 
-    // Function returning a list of an in order traversal of the data structure
+    /**
+     * Returns a list of the elements in the heap in in-order traversal.
+     *
+     * @return an ArrayList containing the elements in in-order
+     */
     public ArrayList<Integer> inOrder() {
         ArrayList<Integer> lst = new ArrayList<>();
         inOrderAux(root, lst);
         return new ArrayList<>(lst);
     }
 
-    // Auxiliary function for in_order
+    /**
+     * Auxiliary function for in-order traversal
+     *
+     * @param n the current node
+     * @param lst the list to store the elements in in-order
+     */
     private void inOrderAux(Node n, ArrayList<Integer> lst) {
         if (n == null) {
             return;
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java
index f4c4c548ffbf..8c313237f88f 100644
--- a/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java
@@ -6,23 +6,80 @@
 public class LeftistHeapTest {
 
     @Test
-    void testLeftistHeap() {
+    void testIsEmpty() {
+        LeftistHeap heap = new LeftistHeap();
+        Assertions.assertTrue(heap.isEmpty(), "Heap should be empty initially.");
+
+        heap.insert(10);
+        Assertions.assertFalse(heap.isEmpty(), "Heap should not be empty after insertion.");
+
+        heap.clear();
+        Assertions.assertTrue(heap.isEmpty(), "Heap should be empty after clearing.");
+    }
+
+    @Test
+    void testInsertAndExtractMin() {
         LeftistHeap heap = new LeftistHeap();
-        Assertions.assertTrue(heap.isEmpty());
         heap.insert(6);
-        Assertions.assertTrue(!heap.isEmpty());
         heap.insert(2);
         heap.insert(3);
         heap.insert(1);
-        heap.inOrder();
-        Assertions.assertTrue(heap.inOrder().toString().equals("[6, 2, 3, 1]"));
-        Assertions.assertTrue(heap.extractMin() == 1);
-        Assertions.assertTrue(heap.inOrder().toString().equals("[6, 2, 3]"));
+
+        Assertions.assertEquals(1, heap.extractMin(), "Minimum should be 1.");
+        Assertions.assertEquals(2, heap.extractMin(), "Next minimum should be 2.");
+        Assertions.assertEquals(3, heap.extractMin(), "Next minimum should be 3.");
+        Assertions.assertEquals(6, heap.extractMin(), "Next minimum should be 6.");
+        Assertions.assertEquals(-1, heap.extractMin(), "Extracting from an empty heap should return -1.");
+    }
+
+    @Test
+    void testMerge() {
+        LeftistHeap heap1 = new LeftistHeap();
+        heap1.insert(1);
+        heap1.insert(3);
+        heap1.insert(5);
+
+        LeftistHeap heap2 = new LeftistHeap();
+        heap2.insert(2);
+        heap2.insert(4);
+        heap2.insert(6);
+
+        heap1.merge(heap2);
+
+        Assertions.assertEquals(1, heap1.extractMin(), "After merging, minimum should be 1.");
+        Assertions.assertEquals(2, heap1.extractMin(), "Next minimum should be 2.");
+        Assertions.assertEquals(3, heap1.extractMin(), "Next minimum should be 3.");
+        Assertions.assertEquals(4, heap1.extractMin(), "Next minimum should be 4.");
+        Assertions.assertEquals(5, heap1.extractMin(), "Next minimum should be 5.");
+        Assertions.assertEquals(6, heap1.extractMin(), "Next minimum should be 6.");
+        Assertions.assertEquals(-1, heap1.extractMin(), "Extracting from an empty heap should return -1.");
+    }
+
+    @Test
+    void testInOrderTraversal() {
+        LeftistHeap heap = new LeftistHeap();
+        heap.insert(10);
+        heap.insert(5);
+        heap.insert(20);
+        heap.insert(15);
+        heap.insert(30);
+
+        Assertions.assertEquals("[20, 15, 30, 5, 10]", heap.inOrder().toString(), "In-order traversal should match the expected output.");
+    }
+
+    @Test
+    void testMultipleExtractions() {
+        LeftistHeap heap = new LeftistHeap();
+        heap.insert(10);
+        heap.insert(5);
+        heap.insert(3);
         heap.insert(8);
-        heap.insert(12);
-        heap.insert(4);
-        Assertions.assertTrue(heap.inOrder().toString().equals("[8, 3, 12, 2, 6, 4]"));
-        heap.clear();
-        Assertions.assertTrue(heap.isEmpty());
+
+        // Extract multiple elements
+        Assertions.assertEquals(3, heap.extractMin());
+        Assertions.assertEquals(5, heap.extractMin());
+        Assertions.assertEquals(8, heap.extractMin());
+        Assertions.assertEquals(10, heap.extractMin());
+        Assertions.assertEquals(-1, heap.extractMin(), "Extracting from an empty heap should return -1.");
     }
 }

From 08bd1ffe731ba3e1098eee389072d63234149d2a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 21:03:33 +0530
Subject: [PATCH 0674/1338] Refactor `AtbashCipher`, add `ParameterizedTest`
 (#5808)

---
 .../thealgorithms/ciphers/AtbashCipher.java   | 92 ++++++++++++-------
 .../com/thealgorithms/ciphers/AtbashTest.java | 43 ++++++---
 2 files changed, 90 insertions(+), 45 deletions(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java b/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java
index c3b673144c63..9169aa82bd75 100644
--- a/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java
@@ -1,68 +1,98 @@
 package com.thealgorithms.ciphers;
 
 /**
- * The Atbash cipher is a simple substitution cipher that replaces each letter
- * in the alphabet with its reverse.
- * For example, 'A' becomes 'Z', 'B' becomes 'Y', and so on. It works
- * identically for both uppercase and lowercase letters.
- * It's a symmetric cipher, meaning applying it twice returns the original text.
- * Hence, the encrypting and the decrypting functions are identical
- * @author https://github.com/Krounosity
- * Learn more: https://en.wikipedia.org/wiki/Atbash
+ * The Atbash cipher is a classic substitution cipher that substitutes each letter
+ * with its opposite letter in the alphabet.
+ *
+ * For example:
+ * - 'A' becomes 'Z', 'B' becomes 'Y', 'C' becomes 'X', and so on.
+ * - Similarly, 'a' becomes 'z', 'b' becomes 'y', and so on.
+ *
+ * The cipher works identically for both uppercase and lowercase letters.
+ * Non-alphabetical characters remain unchanged in the output.
+ *
+ * This cipher is symmetric, meaning that applying the cipher twice will return
+ * the original text. Therefore, the same function is used for both encryption and decryption.
+ *
+ * <p>Usage Example:</p>
+ * <pre>
+ * AtbashCipher cipher = new AtbashCipher("Hello World!");
+ * String encrypted = cipher.convert(); // Output: "Svool Dliow!"
+ * </pre>
+ *
+ * @author <a href="https://github.com/Krounosity">Krounosity</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Atbash">Atbash Cipher (Wikipedia)</a>
  */
-
 public class AtbashCipher {
 
     private String toConvert;
 
-    // Default constructor.
-    AtbashCipher() {
+    public AtbashCipher() {
     }
 
-    // String setting constructor.
-    AtbashCipher(String str) {
-        toConvert = str;
+    /**
+     * Constructor with a string parameter.
+     *
+     * @param str The string to be converted using the Atbash cipher
+     */
+    public AtbashCipher(String str) {
+        this.toConvert = str;
     }
 
-    // String getter method.
+    /**
+     * Returns the current string set for conversion.
+     *
+     * @return The string to be converted
+     */
     public String getString() {
         return toConvert;
     }
 
-    // String setter method.
+    /**
+     * Sets the string to be converted using the Atbash cipher.
+     *
+     * @param str The new string to convert
+     */
     public void setString(String str) {
-        toConvert = str;
+        this.toConvert = str;
     }
 
-    // Checking whether the current character is capital.
+    /**
+     * Checks if a character is uppercase.
+     *
+     * @param ch The character to check
+     * @return {@code true} if the character is uppercase, {@code false} otherwise
+     */
     private boolean isCapital(char ch) {
         return ch >= 'A' && ch <= 'Z';
     }
 
-    // Checking whether the current character is smallcased.
+    /**
+     * Checks if a character is lowercase.
+     *
+     * @param ch The character to check
+     * @return {@code true} if the character is lowercase, {@code false} otherwise
+     */
     private boolean isSmall(char ch) {
         return ch >= 'a' && ch <= 'z';
     }
 
-    // Converting text to atbash cipher code or vice versa.
+    /**
+     * Converts the input string using the Atbash cipher.
+     * Alphabetic characters are substituted with their opposite in the alphabet,
+     * while non-alphabetic characters remain unchanged.
+     *
+     * @return The converted string after applying the Atbash cipher
+     */
     public String convert() {
-
-        // Using StringBuilder to store new string.
         StringBuilder convertedString = new StringBuilder();
 
-        // Iterating for each character.
         for (char ch : toConvert.toCharArray()) {
-
-            // If the character is smallcased.
             if (isSmall(ch)) {
                 convertedString.append((char) ('z' - (ch - 'a')));
-            }
-            // If the character is capital cased.
-            else if (isCapital(ch)) {
+            } else if (isCapital(ch)) {
                 convertedString.append((char) ('Z' - (ch - 'A')));
-            }
-            // Non-alphabetical character.
-            else {
+            } else {
                 convertedString.append(ch);
             }
         }
diff --git a/src/test/java/com/thealgorithms/ciphers/AtbashTest.java b/src/test/java/com/thealgorithms/ciphers/AtbashTest.java
index 26812cf2b0d4..ec34bc26ad72 100644
--- a/src/test/java/com/thealgorithms/ciphers/AtbashTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/AtbashTest.java
@@ -2,27 +2,42 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class AtbashTest {
 
-    @Test
-    public void atbashEncrypt() {
-        AtbashCipher normalToEncrypt = new AtbashCipher("Hello World! 123, @cipher abcDEF ZYX 987 madam zzZ Palindrome!");
-        String expectedText = "Svool Dliow! 123, @xrksvi zyxWVU ABC 987 nzwzn aaA Kzormwilnv!";
+    @ParameterizedTest
+    @MethodSource("cipherTestProvider")
+    public void testAtbashCipher(String input, String expected) {
+        AtbashCipher cipher = new AtbashCipher(input);
+        assertEquals(expected, cipher.convert());
+    }
 
-        normalToEncrypt.setString(normalToEncrypt.convert());
+    private static Stream<Arguments> cipherTestProvider() {
+        return Stream.of(
+            // Basic tests with lowercase and uppercase
+            Arguments.of("Hello", "Svool"), Arguments.of("WORLD", "DLIOW"),
 
-        assertEquals(expectedText, normalToEncrypt.getString());
-    }
+            // Mixed case with spaces and punctuation
+            Arguments.of("Hello World!", "Svool Dliow!"), Arguments.of("123 ABC xyz", "123 ZYX cba"),
+
+            // Palindromes and mixed cases
+            Arguments.of("madam", "nzwzn"), Arguments.of("Palindrome", "Kzormwilnv"),
+
+            // Non-alphabetic characters should remain unchanged
+            Arguments.of("@cipher 123!", "@xrksvi 123!"), Arguments.of("no-change", "ml-xszmtv"),
 
-    @Test
-    public void atbashDecrypt() {
-        AtbashCipher encryptToNormal = new AtbashCipher("Svool Dliow! 123, @xrksvi zyxWVU ABC 987 nzwzn aaA Kzormwilnv!");
-        String expectedText = "Hello World! 123, @cipher abcDEF ZYX 987 madam zzZ Palindrome!";
+            // Empty string and single characters
+            Arguments.of("", ""), Arguments.of("A", "Z"), Arguments.of("z", "a"),
 
-        encryptToNormal.setString(encryptToNormal.convert());
+            // Numbers and symbols
+            Arguments.of("!@#123", "!@#123"),
 
-        assertEquals(expectedText, encryptToNormal.getString());
+            // Full sentence with uppercase, lowercase, symbols, and numbers
+            Arguments.of("Hello World! 123, @cipher abcDEF ZYX 987 madam zzZ Palindrome!", "Svool Dliow! 123, @xrksvi zyxWVU ABC 987 nzwzn aaA Kzormwilnv!"),
+            Arguments.of("Svool Dliow! 123, @xrksvi zyxWVU ABC 987 nzwzn aaA Kzormwilnv!", "Hello World! 123, @cipher abcDEF ZYX 987 madam zzZ Palindrome!"));
     }
 }

From 8a18d451d6ca855f4cd1d5ff3a05f34503b473c3 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 21:09:28 +0530
Subject: [PATCH 0675/1338] Enhance docs, add tests in HeapElement (#5981)

---
 DIRECTORY.md                                  |   1 +
 .../datastructures/heaps/HeapElement.java     | 107 ++++++++++++------
 .../datastructures/heaps/HeapElementTest.java |  55 +++++++++
 3 files changed, 126 insertions(+), 37 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index cd511b4ac61d..b880021a6ddb 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -865,6 +865,7 @@
             * heaps
               * [FibonacciHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
               * [GenericHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java)
+              * [HeapElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java)
               * [KthElementFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java)
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
               * [MedianFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java b/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java
index 7c457a340645..20f33bd2d146 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java
@@ -1,14 +1,24 @@
 package com.thealgorithms.datastructures.heaps;
 
 /**
- * Class for heap elements.<br>
+ * Class representing an element in a heap.
  *
  * <p>
- * A heap element contains two attributes: a key which will be used to build the
- * tree (int or double, either primitive type or object) and any kind of
- * IMMUTABLE object the user sees fit to carry any information he/she likes. Be
- * aware that the use of a mutable object might jeopardize the integrity of this
- * information.
+ * A heap element contains two attributes: a key used for ordering in the heap
+ * (which can be of type int or double, either as primitive types or as wrapper objects)
+ * and an additional immutable object that can store any supplementary information the user desires.
+ * Note that using mutable objects may compromise the integrity of this information.
+ * </p>
+ *
+ * <p>
+ * The key attribute is used to determine the order of elements in the heap,
+ * while the additionalInfo attribute can carry user-defined data associated with the key.
+ * </p>
+ *
+ * <p>
+ * This class provides multiple constructors to accommodate various key types and includes
+ * methods to retrieve the key and additional information.
+ * </p>
  *
  * @author Nicolas Renard
  */
@@ -19,9 +29,10 @@ public class HeapElement {
 
     // Constructors
     /**
-     * @param key : a number of primitive type 'double'
-     * @param info : any kind of IMMUTABLE object. May be null, since the
-     * purpose is only to carry additional information of use for the user
+     * Creates a HeapElement with the specified key and additional information.
+     *
+     * @param key  the key of the element (primitive type double)
+     * @param info any immutable object containing additional information, may be null
      */
     public HeapElement(double key, Object info) {
         this.key = key;
@@ -29,9 +40,10 @@ public HeapElement(double key, Object info) {
     }
 
     /**
-     * @param key : a number of primitive type 'int'
-     * @param info : any kind of IMMUTABLE object. May be null, since the
-     * purpose is only to carry additional information of use for the user
+     * Creates a HeapElement with the specified key and additional information.
+     *
+     * @param key  the key of the element (primitive type int)
+     * @param info any immutable object containing additional information, may be null
      */
     public HeapElement(int key, Object info) {
         this.key = key;
@@ -39,9 +51,10 @@ public HeapElement(int key, Object info) {
     }
 
     /**
-     * @param key : a number of object type 'Integer'
-     * @param info : any kind of IMMUTABLE object. May be null, since the
-     * purpose is only to carry additional information of use for the user
+     * Creates a HeapElement with the specified key and additional information.
+     *
+     * @param key  the key of the element (object type Integer)
+     * @param info any immutable object containing additional information, may be null
      */
     public HeapElement(Integer key, Object info) {
         this.key = key;
@@ -49,9 +62,10 @@ public HeapElement(Integer key, Object info) {
     }
 
     /**
-     * @param key : a number of object type 'Double'
-     * @param info : any kind of IMMUTABLE object. May be null, since the
-     * purpose is only to carry additional information of use for the user
+     * Creates a HeapElement with the specified key and additional information.
+     *
+     * @param key  the key of the element (object type Double)
+     * @param info any immutable object containing additional information, may be null
      */
     public HeapElement(Double key, Object info) {
         this.key = key;
@@ -59,7 +73,9 @@ public HeapElement(Double key, Object info) {
     }
 
     /**
-     * @param key : a number of primitive type 'double'
+     * Creates a HeapElement with the specified key.
+     *
+     * @param key the key of the element (primitive type double)
      */
     public HeapElement(double key) {
         this.key = key;
@@ -67,7 +83,9 @@ public HeapElement(double key) {
     }
 
     /**
-     * @param key : a number of primitive type 'int'
+     * Creates a HeapElement with the specified key.
+     *
+     * @param key the key of the element (primitive type int)
      */
     public HeapElement(int key) {
         this.key = key;
@@ -75,7 +93,9 @@ public HeapElement(int key) {
     }
 
     /**
-     * @param key : a number of object type 'Integer'
+     * Creates a HeapElement with the specified key.
+     *
+     * @param key the key of the element (object type Integer)
      */
     public HeapElement(Integer key) {
         this.key = key;
@@ -83,7 +103,9 @@ public HeapElement(Integer key) {
     }
 
     /**
-     * @param key : a number of object type 'Double'
+     * Creates a HeapElement with the specified key.
+     *
+     * @param key the key of the element (object type Double)
      */
     public HeapElement(Double key) {
         this.key = key;
@@ -92,46 +114,57 @@ public HeapElement(Double key) {
 
     // Getters
     /**
-     * @return the object containing the additional info provided by the user.
+     * Returns the object containing the additional information provided by the user.
+     *
+     * @return the additional information
      */
     public Object getInfo() {
         return additionalInfo;
     }
 
     /**
-     * @return the key value of the element
+     * Returns the key value of the element.
+     *
+     * @return the key of the element
      */
     public double getKey() {
         return key;
     }
 
     // Overridden object methods
+    /**
+     * Returns a string representation of the heap element.
+     *
+     * @return a string describing the key and additional information
+     */
+    @Override
     public String toString() {
-        return "Key: " + key + " - " + additionalInfo.toString();
+        return "Key: " + key + " - " + (additionalInfo != null ? additionalInfo.toString() : "No additional info");
     }
 
     /**
-     * @param otherHeapElement
-     * @return true if the keys on both elements are identical and the
-     * additional info objects are identical.
+     * Compares this heap element to another object for equality.
+     *
+     * @param o the object to compare with
+     * @return true if the keys and additional information are identical, false otherwise
      */
     @Override
     public boolean equals(Object o) {
-        if (o != null) {
-            if (!(o instanceof HeapElement)) {
-                return false;
-            }
-            HeapElement otherHeapElement = (HeapElement) o;
-            return ((this.key == otherHeapElement.key) && (this.additionalInfo.equals(otherHeapElement.additionalInfo)));
+        if (o instanceof HeapElement otherHeapElement) {
+            return this.key == otherHeapElement.key && (this.additionalInfo != null ? this.additionalInfo.equals(otherHeapElement.additionalInfo) : otherHeapElement.additionalInfo == null);
         }
         return false;
     }
 
+    /**
+     * Returns a hash code value for the heap element.
+     *
+     * @return a hash code value for this heap element
+     */
     @Override
     public int hashCode() {
-        int result = 0;
-        result = 31 * result + (int) key;
-        result = 31 * result + (additionalInfo != null ? additionalInfo.hashCode() : 0);
+        int result = 31 * (int) key;
+        result += (additionalInfo != null) ? additionalInfo.hashCode() : 0;
         return result;
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java
new file mode 100644
index 000000000000..d04a9de8a94b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.datastructures.heaps;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+class HeapElementTest {
+
+    @Test
+    void testConstructorAndGetters() {
+        HeapElement element = new HeapElement(5.0, "Info");
+        assertEquals(5.0, element.getKey());
+        assertEquals("Info", element.getInfo());
+    }
+
+    @Test
+    void testConstructorWithNullInfo() {
+        HeapElement element = new HeapElement(10);
+        assertEquals(10, element.getKey());
+        assertNull(element.getInfo());
+    }
+
+    @Test
+    void testToString() {
+        HeapElement element = new HeapElement(7.5, "TestInfo");
+        assertEquals("Key: 7.5 - TestInfo", element.toString());
+
+        HeapElement elementWithoutInfo = new HeapElement(3);
+        assertEquals("Key: 3.0 - No additional info", elementWithoutInfo.toString());
+    }
+
+    @Test
+    void testEquals() {
+        HeapElement element1 = new HeapElement(2.5, "Data");
+        HeapElement element2 = new HeapElement(2.5, "Data");
+        HeapElement element3 = new HeapElement(3.0, "DifferentData");
+
+        assertEquals(element1, element2); // Same key and info
+        assertNotEquals(element1, element3); // Different key
+        assertNotEquals(null, element1); // Check for null
+        assertNotEquals("String", element1); // Check for different type
+    }
+
+    @Test
+    void testHashCode() {
+        HeapElement element1 = new HeapElement(4, "HashMe");
+        HeapElement element2 = new HeapElement(4, "HashMe");
+        HeapElement element3 = new HeapElement(4, "DifferentHash");
+
+        assertEquals(element1.hashCode(), element2.hashCode()); // Same key and info
+        assertNotEquals(element1.hashCode(), element3.hashCode()); // Different info
+    }
+}

From 7e87e5840ef7f86c05329a344477bdeb8dab92ff Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 21:14:30 +0530
Subject: [PATCH 0676/1338] Enhance docs, add tests in `FibonacciHeap` (#5979)

---
 .../datastructures/heaps/FibonacciHeap.java   | 25 +++++
 .../heaps/FibonacciHeapTest.java              | 93 ++++++++++++++++++-
 2 files changed, 115 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
index d248bc3316ed..7a263fc08ac5 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
@@ -1,5 +1,30 @@
 package com.thealgorithms.datastructures.heaps;
 
+/**
+ * The {@code FibonacciHeap} class implements a Fibonacci Heap data structure,
+ * which is a collection of trees that satisfy the minimum heap property.
+ * This heap allows for efficient merging of heaps, as well as faster
+ * decrease-key and delete operations compared to other heap data structures.
+ *
+ * <p>Key features of the Fibonacci Heap include:
+ * <ul>
+ *   <li>Amortized O(1) time complexity for insert and decrease-key operations.</li>
+ *   <li>Amortized O(log n) time complexity for delete and delete-min operations.</li>
+ *   <li>Meld operation that combines two heaps in O(1) time.</li>
+ *   <li>Potential function that helps analyze the amortized time complexity.</li>
+ * </ul>
+ *
+ * <p>This implementation maintains additional statistics such as the total number
+ * of link and cut operations performed during the lifetime of the heap, which can
+ * be accessed through static methods.
+ *
+ * <p>The Fibonacci Heap is composed of nodes represented by the inner class
+ * {@code HeapNode}. Each node maintains a key, rank, marked status, and pointers
+ * to its children and siblings. Nodes can be linked and cut as part of the heap
+ * restructuring processes.
+ *
+ * @see HeapNode
+ */
 public class FibonacciHeap {
 
     private static final double GOLDEN_RATIO = (1 + Math.sqrt(5)) / 2;
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java
index b414bab2b8a0..d911f3ac30d8 100644
--- a/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java
@@ -6,7 +6,7 @@
 public class FibonacciHeapTest {
 
     @Test
-    void testHeap() {
+    void testHeapInsertionAndMinimum() {
         FibonacciHeap fibonacciHeap = new FibonacciHeap();
         fibonacciHeap.insert(5);
         fibonacciHeap.insert(3);
@@ -14,8 +14,95 @@ void testHeap() {
         fibonacciHeap.insert(18);
         fibonacciHeap.insert(33);
 
-        Assertions.assertEquals(fibonacciHeap.findMin().getKey(), 1);
+        Assertions.assertEquals(1, fibonacciHeap.findMin().getKey());
         fibonacciHeap.deleteMin();
-        Assertions.assertEquals(fibonacciHeap.findMin().getKey(), 3);
+        Assertions.assertEquals(3, fibonacciHeap.findMin().getKey());
+    }
+
+    @Test
+    void testDeleteMinOnSingleElementHeap() {
+        FibonacciHeap fibonacciHeap = new FibonacciHeap(10);
+        Assertions.assertEquals(10, fibonacciHeap.findMin().getKey());
+        fibonacciHeap.deleteMin();
+        Assertions.assertTrue(fibonacciHeap.empty());
+    }
+
+    @Test
+    void testHeapMeld() {
+        FibonacciHeap heap1 = new FibonacciHeap();
+        FibonacciHeap heap2 = new FibonacciHeap();
+        heap1.insert(1);
+        heap1.insert(2);
+        heap2.insert(3);
+        heap2.insert(4);
+
+        heap1.meld(heap2);
+        Assertions.assertEquals(1, heap1.findMin().getKey());
+    }
+
+    @Test
+    void testHeapSize() {
+        FibonacciHeap fibonacciHeap = new FibonacciHeap();
+        Assertions.assertEquals(0, fibonacciHeap.size());
+        fibonacciHeap.insert(5);
+        Assertions.assertEquals(1, fibonacciHeap.size());
+        fibonacciHeap.insert(3);
+        Assertions.assertEquals(2, fibonacciHeap.size());
+        fibonacciHeap.deleteMin();
+        Assertions.assertEquals(1, fibonacciHeap.size());
+    }
+
+    @Test
+    void testCountersRep() {
+        FibonacciHeap fibonacciHeap = new FibonacciHeap();
+        fibonacciHeap.insert(5);
+        fibonacciHeap.insert(3);
+        fibonacciHeap.insert(8);
+        fibonacciHeap.insert(1);
+
+        int[] counters = fibonacciHeap.countersRep();
+        Assertions.assertEquals(4, counters[0]);
+        Assertions.assertEquals(0, counters[1]);
+    }
+
+    @Test
+    void testDeleteMinMultipleElements() {
+        FibonacciHeap fibonacciHeap = new FibonacciHeap();
+        fibonacciHeap.insert(5);
+        fibonacciHeap.insert(2);
+        fibonacciHeap.insert(8);
+        fibonacciHeap.insert(1);
+
+        Assertions.assertEquals(1, fibonacciHeap.findMin().getKey());
+        fibonacciHeap.deleteMin();
+        Assertions.assertEquals(2, fibonacciHeap.findMin().getKey());
+    }
+
+    @Test
+    void testInsertNegativeKeys() {
+        FibonacciHeap fibonacciHeap = new FibonacciHeap();
+        fibonacciHeap.insert(-10);
+        fibonacciHeap.insert(-5);
+        fibonacciHeap.insert(-20);
+
+        Assertions.assertEquals(-20, fibonacciHeap.findMin().getKey());
+    }
+
+    @Test
+    void testDeleteOnEmptyHeap() {
+        FibonacciHeap fibonacciHeap = new FibonacciHeap();
+        Assertions.assertThrows(NullPointerException.class, () -> { fibonacciHeap.delete(fibonacciHeap.findMin()); });
+    }
+
+    @Test
+    void testPotentialCalculation() {
+        FibonacciHeap fibonacciHeap = new FibonacciHeap();
+        fibonacciHeap.insert(10);
+        fibonacciHeap.insert(20);
+
+        Assertions.assertEquals(2, fibonacciHeap.potential()); // 2 trees, no marked nodes
+        var node = fibonacciHeap.findMin();
+        fibonacciHeap.delete(node);
+        Assertions.assertEquals(1, fibonacciHeap.potential());
     }
 }

From 4ea30985955ed36d361b586d412363f1c7850db0 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 21:32:07 +0530
Subject: [PATCH 0677/1338] Enhance docs, add tests in `MajorityElement`
 (#5978)

---
 .../hashmap/hashing/MajorityElement.java      | 24 +++++++------
 .../hashmap/hashing/MajorityElementTest.java  | 35 +++++++++++++++++++
 2 files changed, 49 insertions(+), 10 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
index 5424e14c72fd..915e4228b618 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
@@ -3,19 +3,23 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
-/*
-This class finds the majority element(s) in an array of integers.
-A majority element is an element that appears more than or equal to n/2 times, where n is the length
-of the array.
-*/
+
+/**
+ * This class provides a method to find the majority element(s) in an array of integers.
+ * A majority element is defined as an element that appears at least ⌊n/2⌋ times,
+ * where n is the length of the array. If multiple elements qualify as majority elements,
+ * they are all returned in a list.
+ */
 public final class MajorityElement {
     private MajorityElement() {
     }
-    /*
-   This method returns the majority element(s) in the given array of integers.
-   @param nums: an array of integers
-   @return a list of majority elements
-   */
+
+    /**
+     * Returns a list of majority element(s) from the given array of integers.
+     *
+     * @param nums an array of integers
+     * @return a list containing the majority element(s); returns an empty list if none exist
+     */
     public static List<Integer> majority(int[] nums) {
         HashMap<Integer, Integer> numToCount = new HashMap<>();
         for (final var num : nums) {
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java
index 49133ba5ffb5..7dcd5eb7a8f4 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java
@@ -42,4 +42,39 @@ void testMajorityWithEmptyArray() {
         List<Integer> actual = MajorityElement.majority(nums);
         assertEquals(expected, actual);
     }
+
+    @Test
+    void testMajorityWithAllElementsSame() {
+        int[] nums = {5, 5, 5, 5, 5};
+        List<Integer> expected = new ArrayList<>();
+        expected.add(5);
+        List<Integer> actual = MajorityElement.majority(nums);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void testMajorityWithEvenCountAndOneMajorityElement() {
+        int[] nums = {1, 2, 2, 3, 3, 2};
+        List<Integer> expected = new ArrayList<>();
+        expected.add(2);
+        List<Integer> actual = MajorityElement.majority(nums);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void testMajorityWithNoElementsEqualToHalf() {
+        int[] nums = {1, 1, 2, 2, 3, 3, 4};
+        List<Integer> expected = Collections.emptyList();
+        List<Integer> actual = MajorityElement.majority(nums);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void testMajorityWithLargeArray() {
+        int[] nums = {1, 2, 3, 1, 1, 1, 2, 1, 1};
+        List<Integer> expected = new ArrayList<>();
+        expected.add(1);
+        List<Integer> actual = MajorityElement.majority(nums);
+        assertEquals(expected, actual);
+    }
 }

From 26f114cb6036a7b5ea9ad252453edac62384f1e8 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 21:35:31 +0530
Subject: [PATCH 0678/1338] Enhance docs, add tests in `LinearProbingHashMap`
 (#5977)

---
 .../hashmap/hashing/LinearProbingHashMap.java | 43 ++++++++--
 .../hashing/LinearProbingHashMapTest.java     | 83 +++++++++++++++++++
 2 files changed, 118 insertions(+), 8 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java
index c96da27c0331..10d5dc7decae 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java
@@ -2,24 +2,51 @@
 
 import java.util.ArrayList;
 
-/***
- * This class is an implementation of a hash table using linear probing.
+/**
+ * This class implements a hash table using linear probing to resolve collisions.
+ * Linear probing is a collision resolution method where each slot in the hash table is checked in a sequential manner
+ * until an empty slot is found.
+ *
+ * <p>
+ * The class allows for storing key-value pairs, where both the key and value are generic types.
+ * The key must be of a type that implements the Comparable interface to ensure that the keys can be compared for sorting.
+ * </p>
+ *
+ * <p>
+ * This implementation supports basic operations such as:
+ * <ul>
+ *     <li><b>put(Key key, Value value)</b>: Adds a key-value pair to the hash table. If the key already exists, its value is updated.</li>
+ *     <li><b>get(Key key)</b>: Retrieves the value associated with the given key.</li>
+ *     <li><b>delete(Key key)</b>: Removes the key and its associated value from the hash table.</li>
+ *     <li><b>contains(Key key)</b>: Checks if the hash table contains a given key.</li>
+ *     <li><b>size()</b>: Returns the number of key-value pairs in the hash table.</li>
+ *     <li><b>keys()</b>: Returns an iterable collection of keys stored in the hash table.</li>
+ * </ul>
+ * </p>
+ *
+ * <p>
+ * The internal size of the hash table is automatically resized when the load factor exceeds 0.5 or falls below 0.125,
+ * ensuring efficient space utilization.
+ * </p>
+ *
  * @see <a href="https://en.wikipedia.org/wiki/Linear_probing">Linear Probing Hash Table</a>
  *
- * @param <Key> keys type.
- * @param <Value> values type.
+ * @param <Key> the type of keys maintained by this map
+ * @param <Value> the type of mapped values
  */
 public class LinearProbingHashMap<Key extends Comparable<Key>, Value> extends Map<Key, Value> {
     private int hsize; // size of the hash table
-    private Key[] keys;
-    private Value[] values;
-    private int size; // amount of elements in the hash table
+    private Key[] keys; // array to store keys
+    private Value[] values; // array to store values
+    private int size; // number of elements in the hash table
 
+    // Default constructor initializes the table with a default size of 16
     public LinearProbingHashMap() {
         this(16);
     }
 
     @SuppressWarnings("unchecked")
+    // Constructor to initialize the hash table with a specified size
     public LinearProbingHashMap(int size) {
         this.hsize = size;
         keys = (Key[]) new Comparable[size];
@@ -81,7 +108,7 @@ public boolean delete(Key key) {
 
         i = increment(i);
         while (keys[i] != null) {
-            // delete keys[i] an vals[i] and reinsert
+            // Save the key and value for rehashing
             Key keyToRehash = keys[i];
             Value valToRehash = values[i];
             keys[i] = null;
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMapTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMapTest.java
index d0a72a1509ee..34b165d4bbcf 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMapTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMapTest.java
@@ -1,8 +1,91 @@
 package com.thealgorithms.datastructures.hashmap.hashing;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
 class LinearProbingHashMapTest extends MapTest {
+
     @Override
     <Key extends Comparable<Key>, Value> Map<Key, Value> getMap() {
         return new LinearProbingHashMap<>();
     }
+
+    @Test
+    void putNullKey() {
+        Map<Integer, String> map = getMap();
+        assertFalse(map.put(null, "value"), "Putting a null key should return false");
+    }
+
+    @Test
+    void putDuplicateKeys() {
+        Map<Integer, String> map = getMap();
+        map.put(1, "one");
+        map.put(1, "uno");
+        assertEquals("uno", map.get(1), "Value should be updated to 'uno'");
+    }
+
+    @Test
+    void putResizeTest() {
+        Map<Integer, String> map = getMap();
+        for (int i = 0; i < 20; i++) {
+            map.put(i, String.valueOf(i));
+        }
+        assertEquals(20, map.size(), "Map size should be 20 after inserting 20 elements");
+    }
+
+    @Test
+    void deleteNonExistentKey() {
+        Map<Integer, String> map = getMap();
+        assertFalse(map.delete(999), "Deleting a non-existent key should return false");
+    }
+
+    @Test
+    void deleteAndReinsert() {
+        Map<Integer, String> map = getMap();
+        map.put(1, "one");
+        map.delete(1);
+        assertFalse(map.contains(1), "Map should not contain the deleted key");
+        map.put(1, "one again");
+        assertTrue(map.contains(1), "Map should contain the key after reinsertion");
+    }
+
+    @Test
+    void resizeDown() {
+        Map<Integer, String> map = getMap();
+        for (int i = 0; i < 16; i++) {
+            map.put(i, String.valueOf(i));
+        }
+        for (int i = 0; i < 12; i++) {
+            map.delete(i);
+        }
+        assertEquals(4, map.size(), "Map size should be 4 after deleting 12 elements");
+    }
+
+    @Test
+    void keysOrderTest() {
+        Map<Integer, String> map = getMap();
+        for (int i = 10; i > 0; i--) {
+            map.put(i, String.valueOf(i));
+        }
+        int expectedKey = 1;
+        for (Integer key : map.keys()) {
+            assertEquals(expectedKey++, key, "Keys should be in sorted order");
+        }
+    }
+
+    @Test
+    void stressTest() {
+        Map<Integer, String> map = getMap();
+        for (int i = 0; i < 1000; i++) {
+            map.put(i, String.valueOf(i));
+            assertEquals(i + 1, map.size(), "Size should match number of inserted elements");
+        }
+        for (int i = 0; i < 500; i++) {
+            map.delete(i);
+            assertEquals(1000 - (i + 1), map.size(), "Size should decrease correctly");
+        }
+    }
 }

From 84cd883e950b0442c9a66b36aca2e8c4a8a974e1 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 21:38:52 +0530
Subject: [PATCH 0679/1338] Enhance docs, add tests in `Intersection` (#5976)

---
 DIRECTORY.md                                  |  1 +
 .../hashmap/hashing/Intersection.java         | 42 ++++++++--
 .../hashmap/hashing/IntersectionTest.java     | 76 +++++++++++++++++++
 3 files changed, 113 insertions(+), 6 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/hashmap/hashing/IntersectionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b880021a6ddb..1c1c010221a3 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -858,6 +858,7 @@
                 * [GenericHashMapUsingArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java)
                 * [GenericHashMapUsingArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java)
                 * [HashMapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java)
+                * [IntersectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/IntersectionTest.java)
                 * [LinearProbingHashMapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMapTest.java)
                 * [MajorityElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java)
                 * [MapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java
index 54bd10de50fa..0e49218d6348 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java
@@ -1,27 +1,57 @@
 package com.thealgorithms.datastructures.hashmap.hashing;
 
-/*
- * this is algo which implies common mathematical set theory concept
- * called intersection in which result is common values of both the sets
- * here metaphor of sets is HashMap
- */
-
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * The {@code Intersection} class provides a method to compute the intersection of two integer arrays.
+ * The intersection is defined as the set of common elements present in both arrays.
+ * <p>
+ * This class utilizes a HashMap to efficiently count occurrences of elements in the first array,
+ * allowing for an efficient lookup of common elements in the second array.
+ * </p>
+ *
+ * <p>
+ * Example:
+ * <pre>
+ * int[] array1 = {1, 2, 2, 1};
+ * int[] array2 = {2, 2};
+ * List<Integer> result = Intersection.intersection(array1, array2); // result will contain [2, 2]
+ * </pre>
+ * </p>
+ *
+ * <p>
+ * Note: The order of the returned list may vary since it depends on the order of elements
+ * in the input arrays.
+ * </p>
+ */
 public final class Intersection {
 
+    /**
+     * Computes the intersection of two integer arrays.
+     * Steps:
+     * 1. Count the occurrences of each element in the first array using a HashMap.
+     * 2. Iterate over the second array and check if the element is present in the HashMap.
+     * If it is, add it to the result list and decrement the count in the HashMap.
+     * 3. Return the result list containing the intersection of the two arrays.
+     *
+     * @param arr1 the first array of integers
+     * @param arr2 the second array of integers
+     * @return a list containing the intersection of the two arrays, or an empty list if either array is null or empty
+     */
     public static List<Integer> intersection(int[] arr1, int[] arr2) {
         if (arr1 == null || arr2 == null || arr1.length == 0 || arr2.length == 0) {
             return Collections.emptyList();
         }
+
         Map<Integer, Integer> cnt = new HashMap<>(16);
         for (int v : arr1) {
             cnt.put(v, cnt.getOrDefault(v, 0) + 1);
         }
+
         List<Integer> res = new ArrayList<>();
         for (int v : arr2) {
             if (cnt.containsKey(v) && cnt.get(v) > 0) {
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/IntersectionTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/IntersectionTest.java
new file mode 100644
index 000000000000..df6d15fd9ba4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/IntersectionTest.java
@@ -0,0 +1,76 @@
+package com.thealgorithms.datastructures.hashmap.hashing;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class IntersectionTest {
+
+    @Test
+    void testBasicIntersection() {
+        int[] arr1 = {1, 2, 2, 1};
+        int[] arr2 = {2, 2};
+        List<Integer> result = Intersection.intersection(arr1, arr2);
+        assertEquals(List.of(2, 2), result, "Intersection should return [2, 2]");
+    }
+
+    @Test
+    void testNoIntersection() {
+        int[] arr1 = {1, 2, 3};
+        int[] arr2 = {4, 5, 6};
+        List<Integer> result = Intersection.intersection(arr1, arr2);
+        assertTrue(result.isEmpty(), "Intersection should be empty for disjoint sets");
+    }
+
+    @Test
+    void testEmptyArray() {
+        int[] arr1 = {};
+        int[] arr2 = {1, 2, 3};
+        List<Integer> result = Intersection.intersection(arr1, arr2);
+        assertTrue(result.isEmpty(), "Intersection should be empty when first array is empty");
+
+        result = Intersection.intersection(arr2, arr1);
+        assertTrue(result.isEmpty(), "Intersection should be empty when second array is empty");
+    }
+
+    @Test
+    void testNullArray() {
+        int[] arr1 = null;
+        int[] arr2 = {1, 2, 3};
+        List<Integer> result = Intersection.intersection(arr1, arr2);
+        assertTrue(result.isEmpty(), "Intersection should be empty when first array is null");
+
+        result = Intersection.intersection(arr2, arr1);
+        assertTrue(result.isEmpty(), "Intersection should be empty when second array is null");
+    }
+
+    @Test
+    void testMultipleOccurrences() {
+        int[] arr1 = {5, 5, 5, 6};
+        int[] arr2 = {5, 5, 6, 6, 6};
+        List<Integer> result = Intersection.intersection(arr1, arr2);
+        assertEquals(List.of(5, 5, 6), result, "Intersection should return [5, 5, 6]");
+    }
+
+    @Test
+    void testSameElements() {
+        int[] arr1 = {1, 1, 1};
+        int[] arr2 = {1, 1, 1};
+        List<Integer> result = Intersection.intersection(arr1, arr2);
+        assertEquals(List.of(1, 1, 1), result, "Intersection should return [1, 1, 1] for same elements");
+    }
+
+    @Test
+    void testLargeArrays() {
+        int[] arr1 = new int[1000];
+        int[] arr2 = new int[1000];
+        for (int i = 0; i < 1000; i++) {
+            arr1[i] = i;
+            arr2[i] = i;
+        }
+        List<Integer> result = Intersection.intersection(arr1, arr2);
+        assertEquals(1000, result.size(), "Intersection should return all elements for identical large arrays");
+    }
+}

From cd40dfbb41a544e6db55fab0874dfc3e6984f9c3 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 21:47:58 +0530
Subject: [PATCH 0680/1338] Enhance docs, add tests in `HashMapCuckooHashing`
 (#5975)

---
 DIRECTORY.md                                  |   2 +-
 .../hashmap/hashing/HashMapCuckooHashing.java | 117 ++++++++-------
 .../hashmap/HashMapCuckooHashingTest.java     |  94 ------------
 .../hashing/HashMapCuckooHashingTest.java     | 140 ++++++++++++++++++
 4 files changed, 204 insertions(+), 149 deletions(-)
 delete mode 100644 src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 1c1c010221a3..284c396b2796 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -857,12 +857,12 @@
               * hashing
                 * [GenericHashMapUsingArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java)
                 * [GenericHashMapUsingArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java)
+                * [HashMapCuckooHashingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashingTest.java)
                 * [HashMapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java)
                 * [IntersectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/IntersectionTest.java)
                 * [LinearProbingHashMapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMapTest.java)
                 * [MajorityElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java)
                 * [MapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java)
-              * [HashMapCuckooHashingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java)
             * heaps
               * [FibonacciHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
               * [GenericHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
index a67968d7e659..8bcf00730acb 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java
@@ -3,25 +3,26 @@
 import java.util.Objects;
 
 /**
- * This class is an implementation of a hash table using Cuckoo Hashing It uses
- * a dynamic array to lengthen the size of the hash table when load factor > .7
+ * This class implements a hash table using Cuckoo Hashing.
+ * Cuckoo hashing is a type of open-addressing hash table that resolves collisions
+ * by relocating existing keys. It utilizes two hash functions to minimize collisions
+ * and automatically resizes the table when the load factor exceeds 0.7.
  *
- * <a href="https://en.wikipedia.org/wiki/Cuckoo_hashing">...</a>
+ * For more information on cuckoo hashing, refer to
+ * <a href="https://en.wikipedia.org/wiki/Cuckoo_hashing">this Wikipedia page</a>.
  */
 public class HashMapCuckooHashing {
 
-    private int tableSize; // size of the hash table
-    private Integer[] buckets; // array representing the table
-    private final Integer emptySlot;
-    private int size; // number of elements in the hash table
-
-    private int thresh; // threshold for infinite loop checking
+    private int tableSize; // Size of the hash table
+    private Integer[] buckets; // Array representing the hash table
+    private final Integer emptySlot; // Placeholder for deleted slots
+    private int size; // Number of elements in the hash table
+    private int thresh; // Threshold for detecting infinite loops during insertion
 
     /**
-     * Constructor initializes buckets array, hsize, and creates dummy object
-     * for emptySlot
+     * Constructs a HashMapCuckooHashing object with the specified initial table size.
      *
-     * @param tableSize the desired size of the hash map
+     * @param tableSize the initial size of the hash map
      */
     public HashMapCuckooHashing(int tableSize) {
         this.buckets = new Integer[tableSize];
@@ -32,13 +33,11 @@ public HashMapCuckooHashing(int tableSize) {
     }
 
     /**
-     * The 2 Hash Functions takes a given key and finds an index based on its data, 2 distinctive
-     * ways to minimize collisions
+     * Computes the first hash index for a given key using the modulo operation.
      *
-     * @param key the desired key to be converted
-     * @return int an index corresponding to the key
+     * @param key the key for which the hash index is computed
+     * @return an integer index corresponding to the key
      */
-
     public int hashFunction1(int key) {
         int hash = key % tableSize;
         if (hash < 0) {
@@ -47,6 +46,12 @@ public int hashFunction1(int key) {
         return hash;
     }
 
+    /**
+     * Computes the second hash index for a given key using integer division.
+     *
+     * @param key the key for which the hash index is computed
+     * @return an integer index corresponding to the key
+     */
     public int hashFunction2(int key) {
         int hash = key / tableSize;
         hash %= tableSize;
@@ -57,14 +62,14 @@ public int hashFunction2(int key) {
     }
 
     /**
-     * inserts the key into the hash map by wrapping it as an Integer object, then uses while loop
-     * to insert new key if desired place is empty, return. if already occupied, continue while loop
-     * over the new key that has just been pushed out. if while loop continues more than Thresh,
-     * rehash table to new size, then push again.
+     * Inserts a key into the hash table using cuckoo hashing.
+     * If the target bucket is occupied, it relocates the existing key and attempts to insert
+     * it into its alternate location. If the insertion process exceeds the threshold,
+     * the table is resized.
      *
-     * @param key the desired key to be inserted in the hash map
+     * @param key the key to be inserted into the hash table
+     * @throws IllegalArgumentException if the key already exists in the table
      */
-
     public void insertKey2HashTable(int key) {
         Integer wrappedInt = key;
         Integer temp;
@@ -77,7 +82,7 @@ public void insertKey2HashTable(int key) {
         }
 
         if (checkTableContainsKey(key)) {
-            throw new IllegalArgumentException("Key already inside, no duplicates allowed");
+            throw new IllegalArgumentException("Key already exists; duplicates are not allowed.");
         }
 
         while (loopCounter <= thresh) {
@@ -117,9 +122,7 @@ public void insertKey2HashTable(int key) {
     }
 
     /**
-     * creates new HashMapCuckooHashing object, then inserts each of the elements in the previous
-     * table to it with its new hash functions. then refers current array to new table.
-     *
+     * Rehashes the current table to a new size (double the current size) and reinserts existing keys.
      */
     public void reHashTableIncreasesTableSize() {
         HashMapCuckooHashing newT = new HashMapCuckooHashing(tableSize * 2);
@@ -134,15 +137,16 @@ public void reHashTableIncreasesTableSize() {
     }
 
     /**
-     * deletes a key from the hash map and adds an available placeholder
+     * Deletes a key from the hash table, marking its position as available.
      *
-     * @param key the desired key to be deleted
+     * @param key the key to be deleted from the hash table
+     * @throws IllegalArgumentException if the table is empty or if the key is not found
      */
     public void deleteKeyFromHashTable(int key) {
         Integer wrappedInt = key;
         int hash = hashFunction1(key);
         if (isEmpty()) {
-            throw new IllegalArgumentException("Table is empty");
+            throw new IllegalArgumentException("Table is empty, cannot delete.");
         }
 
         if (Objects.equals(buckets[hash], wrappedInt)) {
@@ -157,11 +161,11 @@ public void deleteKeyFromHashTable(int key) {
             size--;
             return;
         }
-        throw new IllegalArgumentException("Key " + key + " already inside, no duplicates allowed");
+        throw new IllegalArgumentException("Key " + key + " not found in the table.");
     }
 
     /**
-     * Displays the hash table line by line
+     * Displays the hash table contents, bucket by bucket.
      */
     public void displayHashtable() {
         for (int i = 0; i < tableSize; i++) {
@@ -175,17 +179,18 @@ public void displayHashtable() {
     }
 
     /**
-     * Finds the index of location based on an inputted key
+     * Finds the index of a given key in the hash table.
      *
-     * @param key the desired key to be found
-     * @return int the index where the key is located
+     * @param key the key to be found
+     * @return the index where the key is located
+     * @throws IllegalArgumentException if the table is empty or the key is not found
      */
     public int findKeyInTable(int key) {
         Integer wrappedInt = key;
         int hash = hashFunction1(key);
 
         if (isEmpty()) {
-            throw new IllegalArgumentException("Table is empty");
+            throw new IllegalArgumentException("Table is empty; cannot find keys.");
         }
 
         if (Objects.equals(buckets[hash], wrappedInt)) {
@@ -194,66 +199,70 @@ public int findKeyInTable(int key) {
 
         hash = hashFunction2(key);
         if (!Objects.equals(buckets[hash], wrappedInt)) {
-            throw new IllegalArgumentException("Key " + key + " not found in table");
+            throw new IllegalArgumentException("Key " + key + " not found in the table.");
         } else {
             return hash;
         }
     }
 
     /**
-     * checks if key is inside without any output other than returned boolean.
+     * Checks if the given key is present in the hash table.
      *
-     * @param key the desired key to be found
-     * @return int the index where the key is located
+     * @param key the key to be checked
+     * @return true if the key exists, false otherwise
      */
     public boolean checkTableContainsKey(int key) {
-        return ((buckets[hashFunction1(key)] != null && buckets[hashFunction1(key)].equals(key)) || (buckets[hashFunction2(key)] != null && buckets[hashFunction2(key)] == key));
+        return ((buckets[hashFunction1(key)] != null && buckets[hashFunction1(key)].equals(key)) || (buckets[hashFunction2(key)] != null && buckets[hashFunction2(key)].equals(key)));
     }
 
     /**
-     * Checks the load factor of the hash table if greater than .7,
-     * automatically lengthens table to prevent further collisions
+     * Checks the load factor of the hash table. If the load factor exceeds 0.7,
+     * the table is resized to prevent further collisions.
+     *
+     * @return the current load factor of the hash table
      */
     public double checkLoadFactor() {
         double factor = (double) size / tableSize;
         if (factor > .7) {
-            System.out.printf("Load factor is %.2f , rehashing table%n", factor);
+            System.out.printf("Load factor is %.2f, rehashing table.%n", factor);
             reHashTableIncreasesTableSize();
         }
         return factor;
     }
 
     /**
-     * isFull returns true if the hash map is full and false if not full
+     * Checks if the hash map is full.
      *
-     * @return boolean is Empty
+     * @return true if the hash map is full, false otherwise
      */
     public boolean isFull() {
-        boolean response = true;
         for (int i = 0; i < tableSize; i++) {
             if (buckets[i] == null || Objects.equals(buckets[i], emptySlot)) {
                 return false;
             }
         }
-        return response;
+        return true;
     }
 
     /**
-     * isEmpty returns true if the hash map is empty and false if not empty
+     * Checks if the hash map is empty.
      *
-     * @return boolean is Empty
+     * @return true if the hash map is empty, false otherwise
      */
     public boolean isEmpty() {
-        boolean response = true;
         for (int i = 0; i < tableSize; i++) {
             if (buckets[i] != null) {
-                response = false;
-                break;
+                return false;
             }
         }
-        return response;
+        return true;
     }
 
+    /**
+     * Returns the current number of keys in the hash table.
+     *
+     * @return the number of keys present in the hash table
+     */
     public int getNumberOfKeysInTable() {
         return size;
     }
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java
deleted file mode 100644
index 14bddeae1c91..000000000000
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java
+++ /dev/null
@@ -1,94 +0,0 @@
-package com.thealgorithms.datastructures.hashmap;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotEquals;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
-
-import com.thealgorithms.datastructures.hashmap.hashing.HashMapCuckooHashing;
-import org.junit.jupiter.api.Test;
-
-class HashMapCuckooHashingTest {
-
-    @Test
-    void insertKey() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        assertEquals(0, hashTable.getNumberOfKeysInTable());
-
-        hashTable.insertKey2HashTable(3);
-
-        assertEquals(1, hashTable.getNumberOfKeysInTable());
-    }
-
-    @Test
-    void getKeyIndex() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        hashTable.insertKey2HashTable(8);
-        hashTable.insertKey2HashTable(4);
-
-        assertNotEquals(-1, hashTable.findKeyInTable(8));
-    }
-
-    @Test
-    void containsKey() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        hashTable.insertKey2HashTable(8);
-        boolean contains = hashTable.checkTableContainsKey(8);
-
-        assertTrue(contains);
-    }
-
-    @Test
-    void removeKey() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        hashTable.insertKey2HashTable(3);
-
-        int initialSize = hashTable.getNumberOfKeysInTable();
-
-        hashTable.deleteKeyFromHashTable(3);
-
-        assertEquals(initialSize - 1, hashTable.getNumberOfKeysInTable());
-    }
-
-    @Test
-    void removeNone() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        try {
-            hashTable.deleteKeyFromHashTable(3);
-        } catch (Exception e) {
-            assertTrue(true);
-            return;
-        }
-        fail();
-    }
-
-    @Test
-    void reHashTableIncreasesTableSize() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        int initialSize = hashTable.getNumberOfKeysInTable();
-
-        hashTable.reHashTableIncreasesTableSize();
-
-        assertEquals(initialSize * 2, hashTable.getNumberOfKeysInTable());
-    }
-
-    @Test
-    void hashFunctionsAreDifferent() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        hashTable.insertKey2HashTable(33);
-
-        assertNotEquals(hashTable.hashFunction1(3), hashTable.hashFunction2(3));
-    }
-
-    @Test
-    void avoidInfiniteLoops() {
-        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
-        hashTable.insertKey2HashTable(0);
-        hashTable.insertKey2HashTable(10);
-        hashTable.insertKey2HashTable(100);
-
-        assertTrue(hashTable.checkTableContainsKey(0));
-        assertTrue(hashTable.checkTableContainsKey(10));
-        assertTrue(hashTable.checkTableContainsKey(100));
-    }
-}
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashingTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashingTest.java
new file mode 100644
index 000000000000..c2f80bfe3210
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashingTest.java
@@ -0,0 +1,140 @@
+package com.thealgorithms.datastructures.hashmap.hashing;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+class HashMapCuckooHashingTest {
+
+    @Test
+    void insertKey() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        assertEquals(0, hashTable.getNumberOfKeysInTable());
+
+        hashTable.insertKey2HashTable(3);
+        assertEquals(1, hashTable.getNumberOfKeysInTable());
+    }
+
+    @Test
+    void getKeyIndex() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(8);
+        hashTable.insertKey2HashTable(4);
+
+        assertNotEquals(-1, hashTable.findKeyInTable(8));
+    }
+
+    @Test
+    void containsKey() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(8);
+        boolean contains = hashTable.checkTableContainsKey(8);
+
+        assertTrue(contains);
+    }
+
+    @Test
+    void removeKey() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(3);
+
+        int initialSize = hashTable.getNumberOfKeysInTable();
+        hashTable.deleteKeyFromHashTable(3);
+
+        assertEquals(initialSize - 1, hashTable.getNumberOfKeysInTable());
+    }
+
+    @Test
+    void removeNone() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        try {
+            hashTable.deleteKeyFromHashTable(3);
+        } catch (Exception e) {
+            assertTrue(true);
+            return;
+        }
+        Assertions.fail("Expected exception when trying to delete a non-existing key.");
+    }
+
+    @Test
+    void reHashTableIncreasesTableSize() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(1);
+        hashTable.insertKey2HashTable(2);
+        hashTable.insertKey2HashTable(3);
+        hashTable.insertKey2HashTable(4);
+        hashTable.insertKey2HashTable(5);
+        hashTable.insertKey2HashTable(6);
+        hashTable.insertKey2HashTable(7);
+        hashTable.insertKey2HashTable(8);
+        hashTable.insertKey2HashTable(9);
+        hashTable.insertKey2HashTable(10); // This should trigger rehashing
+
+        assertEquals(10, hashTable.getNumberOfKeysInTable());
+    }
+
+    @Test
+    void hashFunctionsAreDifferent() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(33);
+
+        assertNotEquals(hashTable.hashFunction1(3), hashTable.hashFunction2(3), "Hash functions should produce different indices.");
+    }
+
+    @Test
+    void avoidInfiniteLoops() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(0);
+        hashTable.insertKey2HashTable(10);
+        hashTable.insertKey2HashTable(100);
+
+        assertTrue(hashTable.checkTableContainsKey(0));
+        assertTrue(hashTable.checkTableContainsKey(10));
+        assertTrue(hashTable.checkTableContainsKey(100));
+    }
+
+    @Test
+    void testLoadFactor() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        for (int i = 1; i <= 8; i++) { // Insert 8 keys to test load factor
+            hashTable.insertKey2HashTable(i);
+        }
+        assertEquals(8, hashTable.getNumberOfKeysInTable());
+        // Check that rehashing occurs when a 9th key is added
+        hashTable.insertKey2HashTable(9);
+        assertTrue(hashTable.getNumberOfKeysInTable() > 8, "Load factor exceeded, table should have been resized.");
+    }
+
+    @Test
+    void testDeleteNonExistentKey() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(1);
+        hashTable.insertKey2HashTable(2);
+
+        Exception exception = null;
+        try {
+            hashTable.deleteKeyFromHashTable(3); // Try deleting a non-existent key
+        } catch (IllegalArgumentException e) {
+            exception = e; // Capture the exception
+        }
+        assertNotNull(exception, "Expected an IllegalArgumentException when deleting a non-existent key.");
+    }
+
+    @Test
+    void testInsertDuplicateKey() {
+        HashMapCuckooHashing hashTable = new HashMapCuckooHashing(10);
+        hashTable.insertKey2HashTable(1);
+        Exception exception = null;
+
+        try {
+            hashTable.insertKey2HashTable(1); // Attempt to insert duplicate key
+        } catch (IllegalArgumentException e) {
+            exception = e; // Capture the exception
+        }
+        assertNotNull(exception, "Expected an IllegalArgumentException for duplicate key insertion.");
+    }
+}

From f5bc2c807dedb338b0be554aa46463b82f272d61 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 21:59:21 +0530
Subject: [PATCH 0681/1338] Add more tests in `HashMap` (#5974)

---
 .../hashmap/hashing/HashMap.java              | 22 ++++++
 .../hashmap/hashing/HashMapTest.java          | 68 +++++++++++++++----
 2 files changed, 75 insertions(+), 15 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
index 1aae122b48ec..aed39c941430 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
@@ -85,6 +85,28 @@ public void display() {
         }
     }
 
+    /**
+     * Clears the contents of the hash map by reinitializing each bucket.
+     */
+    public void clear() {
+        for (int i = 0; i < hashSize; i++) {
+            buckets[i] = new LinkedList<>();
+        }
+    }
+
+    /**
+     * Gets the number of key-value pairs in the hash map.
+     *
+     * @return the number of key-value pairs in the hash map
+     */
+    public int size() {
+        int size = 0;
+        for (int i = 0; i < hashSize; i++) {
+            size += buckets[i].isEmpty() ? 0 : 1;
+        }
+        return size;
+    }
+
     /**
      * A nested static class that represents a linked list used for separate chaining in the hash map.
      *
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java
index 3552bc1aa9c5..ff3ba3ed2571 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java
@@ -17,7 +17,7 @@ public void testInsertAndSearch() {
         assertEquals("Value15", hashMap.search(15));
         assertEquals("Value25", hashMap.search(25));
         assertEquals("Value35", hashMap.search(35));
-        assertNull(hashMap.search(45));
+        assertNull(hashMap.search(45)); // Test for non-existent key
     }
 
     @Test
@@ -29,7 +29,7 @@ public void testDelete() {
 
         assertEquals("Value25", hashMap.search(25));
         hashMap.delete(25);
-        assertNull(hashMap.search(25));
+        assertNull(hashMap.search(25)); // Confirm deletion
     }
 
     @Test
@@ -38,21 +38,22 @@ public void testDisplay() {
         hashMap.insert(15, "Value15");
         hashMap.insert(25, "Value25");
         hashMap.insert(35, "Value35");
-        hashMap.display();
+        // Optionally verify display functionality if it returns a string
+        hashMap.display(); // Manual check during test execution
     }
 
     @Test
     public void testInsertNullKey() {
         HashMap<Integer, String> hashMap = new HashMap<>(10);
         hashMap.insert(null, "NullValue");
-        assertEquals("NullValue", hashMap.search(null));
+        assertEquals("NullValue", hashMap.search(null)); // Verify null key handling
     }
 
     @Test
     public void testInsertNullValue() {
         HashMap<Integer, String> hashMap = new HashMap<>(10);
         hashMap.insert(15, null);
-        assertNull(hashMap.search(15));
+        assertNull(hashMap.search(15)); // Verify null value handling
     }
 
     @Test
@@ -61,12 +62,12 @@ public void testUpdateExistingKey() {
         hashMap.insert(15, "Value15");
         hashMap.insert(15, "UpdatedValue15");
 
-        assertEquals("UpdatedValue15", hashMap.search(15));
+        assertEquals("UpdatedValue15", hashMap.search(15)); // Verify update
     }
 
     @Test
     public void testHandleCollisions() {
-        HashMap<Integer, String> hashMap = new HashMap<>(3);
+        HashMap<Integer, String> hashMap = new HashMap<>(3); // Create a small bucket size to force collisions
         // These keys should collide if the hash function is modulo 3
         hashMap.insert(1, "Value1");
         hashMap.insert(4, "Value4");
@@ -80,17 +81,17 @@ public void testHandleCollisions() {
     @Test
     public void testSearchInEmptyHashMap() {
         HashMap<Integer, String> hashMap = new HashMap<>(10);
-        assertNull(hashMap.search(10));
+        assertNull(hashMap.search(10)); // Confirm search returns null in empty map
     }
 
     @Test
     public void testDeleteNonExistentKey() {
         HashMap<Integer, String> hashMap = new HashMap<>(10);
         hashMap.insert(15, "Value15");
-        hashMap.delete(25);
+        hashMap.delete(25); // Delete non-existent key
 
-        assertEquals("Value15", hashMap.search(15));
-        assertNull(hashMap.search(25));
+        assertEquals("Value15", hashMap.search(15)); // Ensure existing key remains
+        assertNull(hashMap.search(25)); // Confirm non-existent key remains null
     }
 
     @Test
@@ -101,7 +102,7 @@ public void testInsertLargeNumberOfElements() {
         }
 
         for (int i = 0; i < 100; i++) {
-            assertEquals("Value" + i, hashMap.search(i));
+            assertEquals("Value" + i, hashMap.search(i)); // Verify all inserted values
         }
     }
 
@@ -113,7 +114,7 @@ public void testDeleteHeadOfBucket() {
         hashMap.insert(7, "Value7");
 
         hashMap.delete(1);
-        assertNull(hashMap.search(1));
+        assertNull(hashMap.search(1)); // Verify head deletion
         assertEquals("Value4", hashMap.search(4));
         assertEquals("Value7", hashMap.search(7));
     }
@@ -126,7 +127,7 @@ public void testDeleteTailOfBucket() {
         hashMap.insert(7, "Value7");
 
         hashMap.delete(7);
-        assertNull(hashMap.search(7));
+        assertNull(hashMap.search(7)); // Verify tail deletion
         assertEquals("Value1", hashMap.search(1));
         assertEquals("Value4", hashMap.search(4));
     }
@@ -139,8 +140,45 @@ public void testDeleteMiddleElementOfBucket() {
         hashMap.insert(7, "Value7");
 
         hashMap.delete(4);
-        assertNull(hashMap.search(4));
+        assertNull(hashMap.search(4)); // Verify middle element deletion
         assertEquals("Value1", hashMap.search(1));
         assertEquals("Value7", hashMap.search(7));
     }
+
+    @Test
+    public void testResizeHashMap() {
+        HashMap<Integer, String> hashMap = new HashMap<>(2); // Small initial size to force rehashing
+        for (int i = 0; i < 10; i++) {
+            hashMap.insert(i, "Value" + i);
+        }
+
+        // Verify all values after resizing
+        for (int i = 0; i < 10; i++) {
+            assertEquals("Value" + i, hashMap.search(i));
+        }
+    }
+
+    @Test
+    public void testCollisionResolution() {
+        HashMap<String, String> hashMap = new HashMap<>(3);
+        hashMap.insert("abc", "Value1"); // Hash index 0
+        hashMap.insert("cab", "Value2"); // Hash index 0 (collision)
+        hashMap.insert("bac", "Value3"); // Hash index 0 (collision)
+
+        assertEquals("Value1", hashMap.search("abc"));
+        assertEquals("Value2", hashMap.search("cab"));
+        assertEquals("Value3", hashMap.search("bac"));
+    }
+
+    @Test
+    public void testClearHashMap() {
+        HashMap<Integer, String> hashMap = new HashMap<>(10);
+        hashMap.insert(1, "Value1");
+        hashMap.insert(2, "Value2");
+
+        hashMap.clear(); // Assuming clear method resets the hash map
+        assertNull(hashMap.search(1));
+        assertNull(hashMap.search(2));
+        assertEquals(0, hashMap.size()); // Verify size is reset
+    }
 }

From bc6ea1ec87e96eb61aa3cf208d4909aedc31f2f9 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 22:15:16 +0530
Subject: [PATCH 0682/1338] =?UTF-8?q?Enhance=20docs,=20fix=20&=20add=20tes?=
 =?UTF-8?q?ts=20in=20`GenericHashMapUsingArrayL=E2=80=A6=20(#5973)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../hashing/GenericHashMapUsingArrayList.java | 95 +++++++++++++++++--
 .../GenericHashMapUsingArrayListTest.java     | 43 +++++++++
 2 files changed, 128 insertions(+), 10 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java
index a1ef457f3432..89e25f4eb0f7 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java
@@ -3,12 +3,34 @@
 import java.util.ArrayList;
 import java.util.LinkedList;
 
+/**
+ * A generic implementation of a hash map using an array list of linked lists for collision resolution.
+ * This class allows storage of key-value pairs with average-case constant time complexity for insertion,
+ * deletion, and retrieval operations.
+ *
+ * <p>
+ * The hash map uses separate chaining to handle collisions. Each bucket in the hash map is represented
+ * by a linked list that holds nodes containing key-value pairs. When multiple keys hash to the same index,
+ * they are stored in the same linked list.
+ * </p>
+ *
+ * <p>
+ * The hash map automatically resizes itself when the load factor exceeds 0.5. The load factor is defined
+ * as the ratio of the number of entries to the number of buckets. When resizing occurs, all existing entries
+ * are rehashed and inserted into the new buckets.
+ * </p>
+ *
+ * @param <K> the type of keys maintained by this hash map
+ * @param <V> the type of mapped values
+ */
 public class GenericHashMapUsingArrayList<K, V> {
 
-    ArrayList<LinkedList<Node>> buckets;
-    private float lf = 0.5f;
-    private int size;
+    private ArrayList<LinkedList<Node>> buckets; // Array list of buckets (linked lists)
+    private int size; // Number of key-value pairs in the hash map
 
+    /**
+     * Constructs a new empty hash map with an initial capacity of 10 buckets.
+     */
     public GenericHashMapUsingArrayList() {
         buckets = new ArrayList<>();
         for (int i = 0; i < 10; i++) {
@@ -17,6 +39,13 @@ public GenericHashMapUsingArrayList() {
         size = 0;
     }
 
+    /**
+     * Associates the specified value with the specified key in this map.
+     * If the map previously contained a mapping for the key, the old value is replaced.
+     *
+     * @param key the key with which the specified value is to be associated
+     * @param value the value to be associated with the specified key
+     */
     public void put(K key, V value) {
         int hash = Math.abs(key.hashCode() % buckets.size());
         LinkedList<Node> nodes = buckets.get(hash);
@@ -31,25 +60,36 @@ public void put(K key, V value) {
         nodes.add(new Node(key, value));
         size++;
 
-        if ((float) size / buckets.size() > lf) {
+        // Load factor threshold for resizing
+        float loadFactorThreshold = 0.5f;
+        if ((float) size / buckets.size() > loadFactorThreshold) {
             reHash();
         }
     }
 
+    /**
+     * Resizes the hash map by doubling the number of buckets and rehashing existing entries.
+     */
     private void reHash() {
-        ArrayList<LinkedList<Node>> old = buckets;
+        ArrayList<LinkedList<Node>> oldBuckets = buckets;
         buckets = new ArrayList<>();
         size = 0;
-        for (int i = 0; i < old.size() * 2; i++) {
+        for (int i = 0; i < oldBuckets.size() * 2; i++) {
             buckets.add(new LinkedList<>());
         }
-        for (LinkedList<Node> nodes : buckets) {
+        for (LinkedList<Node> nodes : oldBuckets) {
             for (Node node : nodes) {
                 put(node.key, node.val);
             }
         }
     }
 
+    /**
+     * Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.
+     *
+     * @param key the key whose associated value is to be returned
+     * @return the value associated with the specified key, or null if no mapping exists
+     */
     public V get(K key) {
         int hash = Math.abs(key.hashCode() % buckets.size());
         LinkedList<Node> nodes = buckets.get(hash);
@@ -61,6 +101,11 @@ public V get(K key) {
         return null;
     }
 
+    /**
+     * Removes the mapping for the specified key from this map if present.
+     *
+     * @param key the key whose mapping is to be removed from the map
+     */
     public void remove(K key) {
         int hash = Math.abs(key.hashCode() % buckets.size());
         LinkedList<Node> nodes = buckets.get(hash);
@@ -72,18 +117,36 @@ public void remove(K key) {
                 break;
             }
         }
-        nodes.remove(target);
-        size--;
+        if (target != null) {
+            nodes.remove(target);
+            size--;
+        }
     }
 
+    /**
+     * Returns true if this map contains a mapping for the specified key.
+     *
+     * @param key the key whose presence in this map is to be tested
+     * @return true if this map contains a mapping for the specified key
+     */
     public boolean containsKey(K key) {
         return get(key) != null;
     }
 
+    /**
+     * Returns the number of key-value pairs in this map.
+     *
+     * @return the number of key-value pairs
+     */
     public int size() {
         return this.size;
     }
 
+    /**
+     * Returns a string representation of the map, containing all key-value pairs.
+     *
+     * @return a string representation of the map
+     */
     @Override
     public String toString() {
         StringBuilder builder = new StringBuilder();
@@ -96,15 +159,27 @@ public String toString() {
                 builder.append(", ");
             }
         }
+        // Remove trailing comma and space if there are any elements
+        if (builder.length() > 1) {
+            builder.setLength(builder.length() - 2);
+        }
         builder.append("}");
         return builder.toString();
     }
 
+    /**
+     * A private inner class representing a key-value pair (node) in the hash map.
+     */
     private class Node {
-
         K key;
         V val;
 
+        /**
+         * Constructs a new Node with the specified key and value.
+         *
+         * @param key the key of the key-value pair
+         * @param val the value of the key-value pair
+         */
         Node(K key, V val) {
             this.key = key;
             this.val = val;
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java
index 37e43d2aada3..629aaae95753 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java
@@ -50,4 +50,47 @@ void testGenericHashmapWhichUsesArrayAndKeyIsIntegerValueIsString() {
         assertEquals("Washington DC", map.get(101));
         assertTrue(map.containsKey(46));
     }
+
+    @Test
+    void testRemoveNonExistentKey() {
+        GenericHashMapUsingArrayList<String, String> map = new GenericHashMapUsingArrayList<>();
+        map.put("USA", "Washington DC");
+        map.remove("Nepal"); // Attempting to remove a non-existent key
+        assertEquals(1, map.size()); // Size should remain the same
+    }
+
+    @Test
+    void testRehashing() {
+        GenericHashMapUsingArrayList<String, String> map = new GenericHashMapUsingArrayList<>();
+        for (int i = 0; i < 20; i++) {
+            map.put("Key" + i, "Value" + i);
+        }
+        assertEquals(20, map.size()); // Ensure all items were added
+        assertEquals("Value5", map.get("Key5")); // Check retrieval after rehash
+    }
+
+    @Test
+    void testUpdateValueForExistingKey() {
+        GenericHashMapUsingArrayList<String, String> map = new GenericHashMapUsingArrayList<>();
+        map.put("USA", "Washington DC");
+        map.put("USA", "New Washington DC"); // Updating value for existing key
+        assertEquals("New Washington DC", map.get("USA"));
+    }
+
+    @Test
+    void testToStringMethod() {
+        GenericHashMapUsingArrayList<String, String> map = new GenericHashMapUsingArrayList<>();
+        map.put("USA", "Washington DC");
+        map.put("Nepal", "Kathmandu");
+        String expected = "{USA : Washington DC, Nepal : Kathmandu}";
+        assertEquals(expected, map.toString());
+    }
+
+    @Test
+    void testContainsKey() {
+        GenericHashMapUsingArrayList<String, String> map = new GenericHashMapUsingArrayList<>();
+        map.put("USA", "Washington DC");
+        assertTrue(map.containsKey("USA"));
+        assertFalse(map.containsKey("Nepal"));
+    }
 }

From a78b15dc243078b84fdfbc81a97461fb51bf2ecb Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 22:23:32 +0530
Subject: [PATCH 0683/1338] Enhance docs, add tests in MinHeap (#5985)

---
 DIRECTORY.md                                  |   1 +
 .../datastructures/heaps/Heap.java            |   2 +-
 .../datastructures/heaps/HeapElement.java     |   4 +
 .../datastructures/heaps/MinHeap.java         | 248 ++++++++++++++----
 .../datastructures/heaps/MinHeapTest.java     | 141 ++++++++++
 5 files changed, 344 insertions(+), 52 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/heaps/MinHeapTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 284c396b2796..f8bb3711a664 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -871,6 +871,7 @@
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
               * [MedianFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java)
               * [MergeKSortedArraysTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MergeKSortedArraysTest.java)
+              * [MinHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MinHeapTest.java)
               * [MinPriorityQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java)
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/Heap.java b/src/main/java/com/thealgorithms/datastructures/heaps/Heap.java
index 63e101d9b13d..8cb93edf78f3 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/Heap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/Heap.java
@@ -40,5 +40,5 @@ public interface Heap {
      * @param elementIndex int containing the position in the heap of the
      * element to be deleted.
      */
-    void deleteElement(int elementIndex);
+    void deleteElement(int elementIndex) throws EmptyHeapException;
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java b/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java
index 20f33bd2d146..57cc9e37122d 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java
@@ -167,4 +167,8 @@ public int hashCode() {
         result += (additionalInfo != null) ? additionalInfo.hashCode() : 0;
         return result;
     }
+
+    public String getValue() {
+        return additionalInfo.toString();
+    }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
index 46864fba0047..3a4822142b5f 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java
@@ -4,8 +4,25 @@
 import java.util.List;
 
 /**
- * Heap tree where a node's key is higher than or equal to its parent's and
- * lower than or equal to its children's.
+ * A Min Heap implementation where each node's key is lower than or equal to its children's keys.
+ * This data structure provides O(log n) time complexity for insertion and deletion operations,
+ * and O(1) for retrieving the minimum element.
+ *
+ * Properties:
+ * 1. Complete Binary Tree
+ * 2. Parent node's key ≤ Children nodes' keys
+ * 3. Root contains the minimum element
+ *
+ * Example usage:
+ * ```java
+ * List<HeapElement> elements = Arrays.asList(
+ *     new HeapElement(5, "Five"),
+ *     new HeapElement(2, "Two")
+ * );
+ * MinHeap heap = new MinHeap(elements);
+ * heap.insertElement(new HeapElement(1, "One"));
+ * HeapElement min = heap.getElement(); // Returns and removes the minimum element
+ * ```
  *
  * @author Nicolas Renard
  */
@@ -13,113 +30,242 @@ public class MinHeap implements Heap {
 
     private final List<HeapElement> minHeap;
 
+    /**
+     * Constructs a new MinHeap from a list of elements.
+     * Null elements in the input list are ignored with a warning message.
+     *
+     * @param listElements List of HeapElement objects to initialize the heap
+     * @throws IllegalArgumentException if the input list is null
+     */
     public MinHeap(List<HeapElement> listElements) {
+        if (listElements == null) {
+            throw new IllegalArgumentException("Input list cannot be null");
+        }
+
         minHeap = new ArrayList<>();
+
+        // Safe initialization: directly add elements first
         for (HeapElement heapElement : listElements) {
             if (heapElement != null) {
-                insertElement(heapElement);
+                minHeap.add(heapElement);
             } else {
                 System.out.println("Null element. Not added to heap");
             }
         }
+
+        // Heapify the array bottom-up
+        for (int i = minHeap.size() / 2; i >= 0; i--) {
+            heapifyDown(i + 1);
+        }
+
         if (minHeap.isEmpty()) {
             System.out.println("No element has been added, empty heap.");
         }
     }
 
-    // Get the element at a given index. The key for the list is equal to index value - 1
+    /**
+     * Retrieves the element at the specified index without removing it.
+     * Note: The index is 1-based for consistency with heap operations.
+     *
+     * @param elementIndex 1-based index of the element to retrieve
+     * @return HeapElement at the specified index
+     * @throws IndexOutOfBoundsException if the index is invalid
+     */
     public HeapElement getElement(int elementIndex) {
         if ((elementIndex <= 0) || (elementIndex > minHeap.size())) {
-            throw new IndexOutOfBoundsException("Index out of heap range");
+            throw new IndexOutOfBoundsException("Index " + elementIndex + " is out of heap range [1, " + minHeap.size() + "]");
         }
         return minHeap.get(elementIndex - 1);
     }
 
-    // Get the key of the element at a given index
+    /**
+     * Retrieves the key value of an element at the specified index.
+     *
+     * @param elementIndex 1-based index of the element
+     * @return double value representing the key
+     * @throws IndexOutOfBoundsException if the index is invalid
+     */
     private double getElementKey(int elementIndex) {
         if ((elementIndex <= 0) || (elementIndex > minHeap.size())) {
-            throw new IndexOutOfBoundsException("Index out of heap range");
+            throw new IndexOutOfBoundsException("Index " + elementIndex + " is out of heap range [1, " + minHeap.size() + "]");
         }
-
         return minHeap.get(elementIndex - 1).getKey();
     }
 
-    // Swaps two elements in the heap
+    /**
+     * Swaps two elements in the heap.
+     *
+     * @param index1 1-based index of first element
+     * @param index2 1-based index of second element
+     */
     private void swap(int index1, int index2) {
         HeapElement temporaryElement = minHeap.get(index1 - 1);
         minHeap.set(index1 - 1, minHeap.get(index2 - 1));
         minHeap.set(index2 - 1, temporaryElement);
     }
 
-    // Toggle an element up to its right place as long as its key is lower than its parent's
+    /**
+     * Maintains heap properties by moving an element down the heap.
+     * Used specifically during initialization.
+     *
+     * @param elementIndex 1-based index of the element to heapify
+     */
+    private void heapifyDown(int elementIndex) {
+        int smallest = elementIndex - 1; // Convert to 0-based index
+        int leftChild = 2 * elementIndex - 1;
+        int rightChild = 2 * elementIndex;
+
+        // Check if left child is smaller than root
+        if (leftChild < minHeap.size() && minHeap.get(leftChild).getKey() < minHeap.get(smallest).getKey()) {
+            smallest = leftChild;
+        }
+
+        // Check if right child is smaller than smallest so far
+        if (rightChild < minHeap.size() && minHeap.get(rightChild).getKey() < minHeap.get(smallest).getKey()) {
+            smallest = rightChild;
+        }
+
+        // If smallest is not root
+        if (smallest != elementIndex - 1) {
+            HeapElement swap = minHeap.get(elementIndex - 1);
+            minHeap.set(elementIndex - 1, minHeap.get(smallest));
+            minHeap.set(smallest, swap);
+
+            // Recursively heapify the affected sub-tree
+            heapifyDown(smallest + 1); // Convert back to 1-based index
+        }
+    }
+
+    /**
+     * Moves an element up the heap until heap properties are satisfied.
+     * This operation is called after insertion to maintain heap properties.
+     *
+     * @param elementIndex 1-based index of the element to move up
+     */
     private void toggleUp(int elementIndex) {
+        if (elementIndex <= 1) {
+            return;
+        }
+
         double key = minHeap.get(elementIndex - 1).getKey();
-        while (getElementKey((int) Math.floor(elementIndex / 2.0) + 1) > key) {
-            swap(elementIndex, (int) Math.floor(elementIndex / 2.0));
-            elementIndex = (int) Math.floor(elementIndex / 2.0);
+        int parentIndex = (int) Math.floor(elementIndex / 2.0);
+
+        while (elementIndex > 1 && getElementKey(parentIndex) > key) {
+            swap(elementIndex, parentIndex);
+            elementIndex = parentIndex;
+            parentIndex = (int) Math.floor(elementIndex / 2.0);
         }
     }
 
-    // Toggle an element down to its right place as long as its key is higher
-    // than any of its children's
+    /**
+     * Moves an element down the heap until heap properties are satisfied.
+     * This operation is called after deletion to maintain heap properties.
+     *
+     * @param elementIndex 1-based index of the element to move down
+     */
     private void toggleDown(int elementIndex) {
         double key = minHeap.get(elementIndex - 1).getKey();
-        boolean wrongOrder = (key > getElementKey(elementIndex * 2)) || (key > getElementKey(Math.min(elementIndex * 2, minHeap.size())));
-        while ((2 * elementIndex <= minHeap.size()) && wrongOrder) {
-            // Check whether it shall swap the element with its left child or its right one if any.
-            if ((2 * elementIndex < minHeap.size()) && (getElementKey(elementIndex * 2 + 1) < getElementKey(elementIndex * 2))) {
-                swap(elementIndex, 2 * elementIndex + 1);
-                elementIndex = 2 * elementIndex + 1;
-            } else {
-                swap(elementIndex, 2 * elementIndex);
-                elementIndex = 2 * elementIndex;
+        int size = minHeap.size();
+
+        while (true) {
+            int smallest = elementIndex;
+            int leftChild = 2 * elementIndex;
+            int rightChild = 2 * elementIndex + 1;
+
+            if (leftChild <= size && getElementKey(leftChild) < key) {
+                smallest = leftChild;
+            }
+
+            if (rightChild <= size && getElementKey(rightChild) < getElementKey(smallest)) {
+                smallest = rightChild;
+            }
+
+            if (smallest == elementIndex) {
+                break;
             }
-            wrongOrder = (key > getElementKey(elementIndex * 2)) || (key > getElementKey(Math.min(elementIndex * 2, minHeap.size())));
+
+            swap(elementIndex, smallest);
+            elementIndex = smallest;
         }
     }
 
-    private HeapElement extractMin() {
-        HeapElement result = minHeap.get(0);
-        deleteElement(0);
+    /**
+     * Extracts and returns the minimum element from the heap.
+     *
+     * @return HeapElement with the lowest key
+     * @throws EmptyHeapException if the heap is empty
+     */
+    private HeapElement extractMin() throws EmptyHeapException {
+        if (minHeap.isEmpty()) {
+            throw new EmptyHeapException("Cannot extract from empty heap");
+        }
+        HeapElement result = minHeap.getFirst();
+        deleteElement(1);
         return result;
     }
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
-    public final void insertElement(HeapElement element) {
+    public void insertElement(HeapElement element) {
+        if (element == null) {
+            throw new IllegalArgumentException("Cannot insert null element");
+        }
         minHeap.add(element);
         toggleUp(minHeap.size());
     }
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
-    public void deleteElement(int elementIndex) {
+    public void deleteElement(int elementIndex) throws EmptyHeapException {
         if (minHeap.isEmpty()) {
-            try {
-                throw new EmptyHeapException("Attempt to delete an element from an empty heap");
-            } catch (EmptyHeapException e) {
-                e.printStackTrace();
-            }
+            throw new EmptyHeapException("Cannot delete from empty heap");
         }
         if ((elementIndex > minHeap.size()) || (elementIndex <= 0)) {
-            throw new IndexOutOfBoundsException("Index out of heap range");
-        }
-        // The last element in heap replaces the one to be deleted
-        minHeap.set(elementIndex - 1, getElement(minHeap.size()));
-        minHeap.remove(minHeap.size());
-        // Shall the new element be moved up...
-        if (getElementKey(elementIndex) < getElementKey((int) Math.floor(elementIndex / 2.0))) {
-            toggleUp(elementIndex);
-        } // ... or down ?
-        else if (((2 * elementIndex <= minHeap.size()) && (getElementKey(elementIndex) > getElementKey(elementIndex * 2))) || ((2 * elementIndex < minHeap.size()) && (getElementKey(elementIndex) > getElementKey(elementIndex * 2)))) {
-            toggleDown(elementIndex);
+            throw new IndexOutOfBoundsException("Index " + elementIndex + " is out of heap range [1, " + minHeap.size() + "]");
+        }
+
+        // Replace with last element and remove last position
+        minHeap.set(elementIndex - 1, minHeap.getLast());
+        minHeap.removeLast();
+
+        // No need to toggle if we just removed the last element
+        if (!minHeap.isEmpty() && elementIndex <= minHeap.size()) {
+            // Determine whether to toggle up or down
+            if (elementIndex > 1 && getElementKey(elementIndex) < getElementKey((int) Math.floor(elementIndex / 2.0))) {
+                toggleUp(elementIndex);
+            } else {
+                toggleDown(elementIndex);
+            }
         }
     }
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
     public HeapElement getElement() throws EmptyHeapException {
-        try {
-            return extractMin();
-        } catch (Exception e) {
-            throw new EmptyHeapException("Heap is empty. Error retrieving element", e);
-        }
+        return extractMin();
+    }
+
+    /**
+     * Returns the current size of the heap.
+     *
+     * @return number of elements in the heap
+     */
+    public int size() {
+        return minHeap.size();
+    }
+
+    /**
+     * Checks if the heap is empty.
+     *
+     * @return true if the heap contains no elements
+     */
+    public boolean isEmpty() {
+        return minHeap.isEmpty();
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/MinHeapTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/MinHeapTest.java
new file mode 100644
index 000000000000..1c2caf54cdb1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/MinHeapTest.java
@@ -0,0 +1,141 @@
+package com.thealgorithms.datastructures.heaps;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class MinHeapTest {
+
+    private MinHeap heap;
+
+    @BeforeEach
+    void setUp() {
+        // Create a fresh heap for each test
+        List<HeapElement> elements = Arrays.asList(new HeapElement(5.0, "Five"), new HeapElement(2.0, "Two"), new HeapElement(8.0, "Eight"), new HeapElement(1.0, "One"), new HeapElement(9.0, "Nine"));
+        heap = new MinHeap(elements);
+    }
+
+    @Test
+    void testConstructorWithNullList() {
+        assertThrows(IllegalArgumentException.class, () -> new MinHeap(null));
+    }
+
+    @Test
+    void testConstructorWithEmptyList() {
+        MinHeap emptyHeap = new MinHeap(new ArrayList<>());
+        assertTrue(emptyHeap.isEmpty());
+    }
+
+    @Test
+    void testConstructorWithNullElements() {
+        List<HeapElement> elements = Arrays.asList(new HeapElement(1.0, "One"), null, new HeapElement(2.0, "Two"));
+        MinHeap heap = new MinHeap(elements);
+        assertEquals(2, heap.size());
+    }
+
+    @Test
+    void testInsertElement() {
+        heap.insertElement(new HeapElement(0.5, "Half"));
+        assertEquals(0.5, heap.getElement(1).getKey());
+        assertEquals(6, heap.size());
+    }
+
+    @Test
+    void testInsertNullElement() {
+        assertThrows(IllegalArgumentException.class, () -> heap.insertElement(null));
+    }
+
+    @Test
+    void testGetElementAtIndex() {
+        HeapElement element = heap.getElement(1);
+        assertEquals(1.0, element.getKey());
+        assertEquals("One", element.getValue());
+    }
+
+    @Test
+    void testGetElementAtInvalidIndex() {
+        assertThrows(IndexOutOfBoundsException.class, () -> heap.getElement(0));
+        assertThrows(IndexOutOfBoundsException.class, () -> heap.getElement(10));
+    }
+
+    @Test
+    void testDeleteElement() throws EmptyHeapException {
+        heap.deleteElement(1);
+        assertEquals(2.0, heap.getElement(1).getKey());
+        assertEquals(4, heap.size());
+    }
+
+    @Test
+    void testDeleteElementAtInvalidIndex() {
+        assertThrows(IndexOutOfBoundsException.class, () -> heap.deleteElement(0));
+        assertThrows(IndexOutOfBoundsException.class, () -> heap.deleteElement(10));
+    }
+
+    @Test
+    void testDeleteFromEmptyHeap() {
+        MinHeap emptyHeap = new MinHeap(new ArrayList<>());
+        assertThrows(EmptyHeapException.class, () -> emptyHeap.deleteElement(1));
+    }
+
+    @Test
+    void testExtractMin() throws EmptyHeapException {
+        HeapElement min = heap.getElement();
+        assertEquals(1.0, min.getKey());
+        assertEquals("One", min.getValue());
+        assertEquals(4, heap.size());
+
+        min = heap.getElement();
+        assertEquals(2.0, min.getKey());
+        assertEquals(3, heap.size());
+    }
+
+    @Test
+    void testExtractMinFromEmptyHeap() {
+        MinHeap emptyHeap = new MinHeap(new ArrayList<>());
+        assertThrows(EmptyHeapException.class, () -> emptyHeap.getElement());
+    }
+
+    @Test
+    void testHeapOrder() {
+        // Test that parent is always smaller than or equal to children
+        for (int i = 1; i <= heap.size() / 2; i++) {
+            double parentKey = heap.getElement(i).getKey();
+
+            // Check left child
+            if (2 * i <= heap.size()) {
+                assertTrue(parentKey <= heap.getElement(2 * i).getKey());
+            }
+
+            // Check right child
+            if (2 * i + 1 <= heap.size()) {
+                assertTrue(parentKey <= heap.getElement(2 * i + 1).getKey());
+            }
+        }
+    }
+
+    @Test
+    void testSizeAndEmpty() {
+        assertEquals(5, heap.size());
+        assertFalse(heap.isEmpty());
+
+        // Remove all elements
+        while (!heap.isEmpty()) {
+            try {
+                heap.getElement();
+            } catch (EmptyHeapException e) {
+                Assertions.fail("Should not throw EmptyHeapException while heap is not empty");
+            }
+        }
+
+        assertEquals(0, heap.size());
+        assertTrue(heap.isEmpty());
+    }
+}

From 474e0dea02dcdd30fbc03c303b9c5fe10fc1f227 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 22:27:43 +0530
Subject: [PATCH 0684/1338] Enhance docs, add more tests in `WelshPowell`
 (#5971)

---
 .../datastructures/graphs/WelshPowell.java    | 114 ++++++++++++++++--
 .../graphs/WelshPowellTest.java               |  62 ++++++----
 2 files changed, 142 insertions(+), 34 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java b/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
index 0981638d4903..26ca97736fe9 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
@@ -5,21 +5,41 @@
 import java.util.HashSet;
 import java.util.stream.IntStream;
 
-/*
- *  The Welsh-Powell algorithm is a graph coloring algorithm
- *  used for coloring a graph with the minimum number of colors.
- *  https://en.wikipedia.org/wiki/Graph_coloring
+/**
+ * The Welsh-Powell algorithm is a graph coloring algorithm that aims to color a graph
+ * using the minimum number of colors such that no two adjacent vertices share the same color.
+ *
+ * <p>
+ * The algorithm works by:
+ * <ol>
+ * <li>Sorting the vertices in descending order based on their degrees (number of edges connected).</li>
+ * <li>Iterating through each vertex and assigning it the smallest available color that has not been used by its adjacent vertices.</li>
+ * <li>Coloring adjacent vertices with the same color is avoided.</li>
+ * </ol>
+ * </p>
+ *
+ * <p>
+ * For more information, see <a href="https://en.wikipedia.org/wiki/Graph_coloring">Graph Coloring</a>.
+ * </p>
  */
-
 public final class WelshPowell {
-    private static final int BLANK_COLOR = -1; // Representing uncolored state
+    private static final int BLANK_COLOR = -1; // Constant representing an uncolored state
 
     private WelshPowell() {
     }
 
+    /**
+     * Represents a graph using an adjacency list.
+     */
     static final class Graph {
-        private HashSet<Integer>[] adjacencyLists;
-
+        private final HashSet<Integer>[] adjacencyLists;
+
+        /**
+         * Initializes a graph with a specified number of vertices.
+         *
+         * @param vertices the number of vertices in the graph
+         * @throws IllegalArgumentException if the number of vertices is negative
+         */
         private Graph(int vertices) {
             if (vertices < 0) {
                 throw new IllegalArgumentException("Number of vertices cannot be negative");
@@ -29,6 +49,13 @@ private Graph(int vertices) {
             Arrays.setAll(adjacencyLists, i -> new HashSet<>());
         }
 
+        /**
+         * Adds an edge between two vertices in the graph.
+         *
+         * @param nodeA one end of the edge
+         * @param nodeB the other end of the edge
+         * @throws IllegalArgumentException if the vertices are out of bounds or if a self-loop is attempted
+         */
         private void addEdge(int nodeA, int nodeB) {
             validateVertex(nodeA);
             validateVertex(nodeB);
@@ -39,21 +66,46 @@ private void addEdge(int nodeA, int nodeB) {
             adjacencyLists[nodeB].add(nodeA);
         }
 
+        /**
+         * Validates that the vertex index is within the bounds of the graph.
+         *
+         * @param vertex the index of the vertex to validate
+         * @throws IllegalArgumentException if the vertex is out of bounds
+         */
         private void validateVertex(int vertex) {
             if (vertex < 0 || vertex >= getNumVertices()) {
                 throw new IllegalArgumentException("Vertex " + vertex + " is out of bounds");
             }
         }
 
+        /**
+         * Returns the adjacency list for a specific vertex.
+         *
+         * @param vertex the index of the vertex
+         * @return the set of adjacent vertices
+         */
         HashSet<Integer> getAdjacencyList(int vertex) {
             return adjacencyLists[vertex];
         }
 
+        /**
+         * Returns the number of vertices in the graph.
+         *
+         * @return the number of vertices
+         */
         int getNumVertices() {
             return adjacencyLists.length;
         }
     }
 
+    /**
+     * Creates a graph with the specified number of vertices and edges.
+     *
+     * @param numberOfVertices the total number of vertices
+     * @param listOfEdges a 2D array representing edges where each inner array contains two vertex indices
+     * @return a Graph object representing the created graph
+     * @throws IllegalArgumentException if the edge array is invalid or vertices are out of bounds
+     */
     public static Graph makeGraph(int numberOfVertices, int[][] listOfEdges) {
         Graph graph = new Graph(numberOfVertices);
         for (int[] edge : listOfEdges) {
@@ -65,6 +117,12 @@ public static Graph makeGraph(int numberOfVertices, int[][] listOfEdges) {
         return graph;
     }
 
+    /**
+     * Finds the coloring of the given graph using the Welsh-Powell algorithm.
+     *
+     * @param graph the input graph to color
+     * @return an array of integers where each index represents a vertex and the value represents the color assigned
+     */
     public static int[] findColoring(Graph graph) {
         int[] colors = initializeColors(graph.getNumVertices());
         Integer[] sortedVertices = getSortedNodes(graph);
@@ -83,30 +141,70 @@ public static int[] findColoring(Graph graph) {
         return colors;
     }
 
+    /**
+     * Helper method to check if a color is unassigned
+     *
+     * @param color the color to check
+     * @return {@code true} if the color is unassigned, {@code false} otherwise
+     */
     private static boolean isBlank(int color) {
         return color == BLANK_COLOR;
     }
 
+    /**
+     * Checks if a vertex has adjacent colored vertices
+     *
+     * @param graph the input graph
+     * @param vertex the vertex to check
+     * @param colors the array of colors assigned to the vertices
+     * @return {@code true} if the vertex has adjacent colored vertices, {@code false} otherwise
+     */
     private static boolean isAdjacentToColored(Graph graph, int vertex, int[] colors) {
         return graph.getAdjacencyList(vertex).stream().anyMatch(otherVertex -> !isBlank(colors[otherVertex]));
     }
 
+    /**
+     * Initializes the colors array with blank color
+     *
+     * @param numberOfVertices the number of vertices in the graph
+     * @return an array of integers representing the colors assigned to the vertices
+     */
     private static int[] initializeColors(int numberOfVertices) {
         int[] colors = new int[numberOfVertices];
         Arrays.fill(colors, BLANK_COLOR);
         return colors;
     }
 
+    /**
+     * Sorts the vertices by their degree in descending order
+     *
+     * @param graph the input graph
+     * @return an array of integers representing the vertices sorted by degree
+     */
     private static Integer[] getSortedNodes(final Graph graph) {
         return IntStream.range(0, graph.getNumVertices()).boxed().sorted(Comparator.comparingInt(v -> - graph.getAdjacencyList(v).size())).toArray(Integer[] ::new);
     }
 
+    /**
+     * Computes the colors already used by the adjacent vertices
+     *
+     * @param graph the input graph
+     * @param vertex the vertex to check
+     * @param colors the array of colors assigned to the vertices
+     * @return an array of booleans representing the colors used by the adjacent vertices
+     */
     private static boolean[] computeUsedColors(final Graph graph, final int vertex, final int[] colors) {
         boolean[] usedColors = new boolean[graph.getNumVertices()];
         graph.getAdjacencyList(vertex).stream().map(neighbor -> colors[neighbor]).filter(color -> !isBlank(color)).forEach(color -> usedColors[color] = true);
         return usedColors;
     }
 
+    /**
+     * Finds the first unused color
+     *
+     * @param usedColors the array of colors used by the adjacent vertices
+     * @return the first unused color
+     */
     private static int firstUnusedColor(boolean[] usedColors) {
         return IntStream.range(0, usedColors.length).filter(color -> !usedColors[color]).findFirst().getAsInt();
     }
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java
index b37657db5c05..f45c4e10be56 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java
@@ -34,26 +34,25 @@ void testCompleteGraph() {
         assertEquals(3, countDistinctColors(colors));
     }
 
-    // The following test originates from the following website : https://www.geeksforgeeks.org/welsh-powell-graph-colouring-algorithm/
     @Test
     void testComplexGraph() {
         int[][] edges = {
-            {0, 7}, // A-H
-            {0, 1}, // A-B
-            {1, 3}, // B-D
-            {2, 3}, // C-D
-            {3, 8}, // D-I
-            {3, 10}, // D-K
-            {4, 10}, // E-K
-            {4, 5}, // E-F
-            {5, 6}, // F-G
-            {6, 10}, // G-K
-            {6, 7}, // G-H
-            {7, 8}, // H-I
-            {7, 9}, // H-J
-            {7, 10}, // H-K
-            {8, 9}, // I-J
-            {9, 10}, // J-K
+            {0, 7},
+            {0, 1},
+            {1, 3},
+            {2, 3},
+            {3, 8},
+            {3, 10},
+            {4, 10},
+            {4, 5},
+            {5, 6},
+            {6, 10},
+            {6, 7},
+            {7, 8},
+            {7, 9},
+            {7, 10},
+            {8, 9},
+            {9, 10},
         };
 
         final var graph = WelshPowell.makeGraph(11, edges); // 11 vertices from A (0) to K (10)
@@ -86,24 +85,35 @@ void testInvalidEdgeArray() {
 
     @Test
     void testWithPreColoredVertex() {
-        // Create a linear graph with 4 vertices and edges connecting them in sequence
         final var graph = WelshPowell.makeGraph(4, new int[][] {{0, 1}, {1, 2}, {2, 3}});
-
-        // Apply the Welsh-Powell coloring algorithm to the graph
         int[] colors = WelshPowell.findColoring(graph);
-
-        // Validate that the coloring is correct (no two adjacent vertices have the same color)
         assertTrue(isColoringValid(graph, colors));
-
-        // Check if the algorithm has used at least 2 colors (expected for a linear graph)
         assertTrue(countDistinctColors(colors) >= 2);
-
-        // Verify that all vertices have been assigned a color
         for (int color : colors) {
             assertTrue(color >= 0);
         }
     }
 
+    @Test
+    void testLargeGraph() {
+        int[][] edges = {{0, 1}, {1, 2}, {2, 3}, {3, 4}, {4, 5}, {5, 0}, {6, 7}, {7, 8}, {8, 6}, {9, 10}, {10, 11}, {11, 9}, {12, 13}, {13, 14}, {14, 15}};
+
+        final var graph = WelshPowell.makeGraph(16, edges); // 16 vertices
+        int[] colors = WelshPowell.findColoring(graph);
+        assertTrue(isColoringValid(graph, colors));
+        assertEquals(3, countDistinctColors(colors)); // Expecting a maximum of 3 colors
+    }
+
+    @Test
+    void testStarGraph() {
+        int[][] edges = {{0, 1}, {0, 2}, {0, 3}, {0, 4}};
+
+        final var graph = WelshPowell.makeGraph(5, edges); // 5 vertices in a star formation
+        int[] colors = WelshPowell.findColoring(graph);
+        assertTrue(isColoringValid(graph, colors));
+        assertEquals(2, countDistinctColors(colors)); // Star graph can be colored with 2 colors
+    }
+
     private boolean isColoringValid(Graph graph, int[] colors) {
         if (Arrays.stream(colors).anyMatch(n -> n < 0)) {
             return false;

From c6571382d9d816a93ded8b63b888b2ee905ccf41 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 23:21:13 +0530
Subject: [PATCH 0685/1338] Enhance docs, add tests in `TarjansAlgorithm`
 (#5970)

---
 .../graphs/TarjansAlgorithm.java              | 149 ++++++++++--------
 .../graphs/TarjansAlgorithmTest.java          |  90 +++++++++--
 2 files changed, 158 insertions(+), 81 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
index de50044256c6..91974ba13319 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java
@@ -5,66 +5,73 @@
 import java.util.Stack;
 
 /**
- * Java program that implements Tarjan's Algorithm.
- * @author <a href="https://github.com/shivu2002a">Shivanagouda S A</a>
+ * Java program that implements Tarjan's Algorithm to find Strongly Connected Components (SCCs) in a directed graph.
+ *
  * <p>
- * Tarjan's algorithm is a linear time algorithm to find the strongly connected components of a
-directed graph, which, from here onwards will be referred as SCC.
-
- * A graph is said to be strongly connected if every vertex is reachable from every other vertex.
-The SCCs of a directed graph form a partition into subgraphs that are themselves strongly
-connected. Single node is always a SCC.
-
- * Example:
-0 --------> 1 -------> 3 --------> 4
-^          /
-|         /
-|        /
-|       /
-|      /
-|     /
-|    /
-|   /
-|  /
-| /
-|V
-2
-
-For the above graph, the SCC list goes as follows:
-1, 2, 0
-3
-4
-
-We can also see that order of the nodes in an SCC doesn't matter since they are in cycle.
-
-{@summary}
-Tarjan's Algorithm:
- * DFS search produces a DFS tree
- * Strongly Connected Components form subtrees of the DFS tree.
- * If we can find the head of these subtrees, we can get all the nodes in that subtree (including
-the head) and that will be one SCC.
- * There is no back edge from one SCC to another (here can be cross edges, but they will not be
-used).
-
- * Kosaraju Algorithm aims at doing the same but uses two DFS traversalse whereas Tarjan’s
-algorithm does the same in a single DFS, which leads to much lower constant factors in the latter.
-
+ * Tarjan's algorithm is a linear time algorithm (O(V + E)) that identifies the SCCs of a directed graph.
+ * An SCC is a maximal subgraph where every vertex is reachable from every other vertex within the subgraph.
+ *
+ * <h3>Algorithm Overview:</h3>
+ * <ul>
+ * <li>DFS Search: A depth-first search (DFS) is performed on the graph to generate a DFS tree.</li>
+ * <li>Identification of SCCs: SCCs correspond to subtrees within this DFS tree.</li>
+ * <li>Low-Link Values: For each node, a low-link value is maintained, which indicates the earliest visited
+ * vertex (the one with the minimum insertion time) that can be reached from that subtree.</li>
+ * <li>Stack Usage: Nodes are stored in a stack during DFS. When an SCC is identified, nodes are popped from
+ * the stack until the head of the SCC is reached.</li>
+ * </ul>
+ *
+ * <p>
+ * Example of a directed graph:
+ * <pre>
+ *  0 --------> 1 -------> 3 --------> 4
+ *  ^          /
+ *  |         /
+ *  |        /
+ *  |       /
+ *  |      /
+ *  |     /
+ *  |    /
+ *  |   /
+ *  |  /
+ *  | /
+ *  V
+ *  2
+ * </pre>
+ *
+ * <p>
+ * For the above graph, the SCC list is as follows:
+ * <ul>
+ * <li>1, 2, 0</li>
+ * <li>3</li>
+ * <li>4</li>
+ * </ul>
+ * The order of nodes in an SCC does not matter as they form cycles.
+ *
+ * <h3>Comparison with Kosaraju's Algorithm:</h3>
+ * <p>
+ * Kosaraju's algorithm also identifies SCCs but does so using two DFS traversals.
+ * In contrast, Tarjan's algorithm achieves this in a single DFS traversal, leading to improved performance
+ * in terms of constant factors.
+ * </p>
  */
 public class TarjansAlgorithm {
 
-    // Timer for tracking lowtime and insertion time
+    // Timer for tracking low time and insertion time
     private int time;
 
-    private final List<List<Integer>> sccList = new ArrayList<List<Integer>>();
+    // List to store all strongly connected components
+    private final List<List<Integer>> sccList = new ArrayList<>();
 
+    /**
+     * Finds and returns the strongly connected components (SCCs) of the directed graph.
+     *
+     * @param v the number of vertices in the graph
+     * @param graph the adjacency list representation of the graph
+     * @return a list of lists, where each inner list represents a strongly connected component
+     */
     public List<List<Integer>> stronglyConnectedComponents(int v, List<List<Integer>> graph) {
-
-        // Initially all vertices as unvisited, insertion and low time are undefined
-
-        // insertionTime:Time when a node is visited 1st time while DFS traversal
-
-        // lowTime: indicates the earliest visited vertex (the vertex with minimum insertion time)
-        // that can be reached from a subtree rooted with a particular node.
+        // Initialize arrays for insertion time and low-link values
         int[] lowTime = new int[v];
         int[] insertionTime = new int[v];
         for (int i = 0; i < v; i++) {
@@ -72,11 +79,11 @@ public List<List<Integer>> stronglyConnectedComponents(int v, List<List<Integer>
             lowTime[i] = -1;
         }
 
-        // To check if element is present in stack
+        // Track if vertices are in the stack
         boolean[] isInStack = new boolean[v];
 
-        // Store nodes during DFS
-        Stack<Integer> st = new Stack<Integer>();
+        // Stack to hold nodes during DFS
+        Stack<Integer> st = new Stack<>();
 
         for (int i = 0; i < v; i++) {
             if (insertionTime[i] == -1) {
@@ -87,36 +94,44 @@ public List<List<Integer>> stronglyConnectedComponents(int v, List<List<Integer>
         return sccList;
     }
 
+    /**
+     * A utility function to perform DFS and find SCCs.
+     *
+     * @param u the current vertex being visited
+     * @param lowTime array to keep track of the low-link values
+     * @param insertionTime array to keep track of the insertion times
+     * @param isInStack boolean array indicating if a vertex is in the stack
+     * @param st the stack used for DFS
+     * @param graph the adjacency list representation of the graph
+     */
     private void stronglyConnCompsUtil(int u, int[] lowTime, int[] insertionTime, boolean[] isInStack, Stack<Integer> st, List<List<Integer>> graph) {
-
-        // Initialize insertion time and lowTime value of current node
+        // Set insertion time and low-link value
         insertionTime[u] = time;
         lowTime[u] = time;
-        time += 1;
+        time++;
 
-        // Push current node into stack
+        // Push current node onto the stack
         isInStack[u] = true;
         st.push(u);
 
-        // Go through all vertices adjacent to this
+        // Explore adjacent vertices
         for (Integer vertex : graph.get(u)) {
-            // If the adjacent node is unvisited, do DFS
             if (insertionTime[vertex] == -1) {
                 stronglyConnCompsUtil(vertex, lowTime, insertionTime, isInStack, st, graph);
-                // update lowTime for the current node comparing lowtime of adj node
+                // Update low-link value
                 lowTime[u] = Math.min(lowTime[u], lowTime[vertex]);
             } else if (isInStack[vertex]) {
-                // If adj node is in stack, update low
+                // Vertex is in the stack; update low-link value
                 lowTime[u] = Math.min(lowTime[u], insertionTime[vertex]);
             }
         }
-        // If lowtime and insertion time are same, current node is the head of an SCC
-        //  head node found, get all the nodes in this SCC
+
+        // Check if the current vertex is the root of an SCC
         if (lowTime[u] == insertionTime[u]) {
             int w = -1;
-            var scc = new ArrayList<Integer>();
+            List<Integer> scc = new ArrayList<>();
 
-            // Stack has all the nodes of the current SCC
+            // Pop vertices from the stack until the root is found
             while (w != u) {
                 w = st.pop();
                 scc.add(w);
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java
index dc81d99dd0bf..314cc415815d 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.datastructures.graphs;
 
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -9,11 +9,11 @@
 
 public class TarjansAlgorithmTest {
 
-    TarjansAlgorithm tarjansAlgo = new TarjansAlgorithm();
+    private final TarjansAlgorithm tarjansAlgo = new TarjansAlgorithm();
 
     @Test
-    public void findStronglyConnectedComps() {
-        var v = 5;
+    public void testFindStronglyConnectedComponents() {
+        int v = 5;
         var graph = new ArrayList<List<Integer>>();
         for (int i = 0; i < v; i++) {
             graph.add(new ArrayList<>());
@@ -32,23 +32,20 @@ public void findStronglyConnectedComps() {
             4
         */
         List<List<Integer>> expectedResult = new ArrayList<>();
-
-        expectedResult.add(Arrays.asList(4));
-        expectedResult.add(Arrays.asList(3));
+        expectedResult.add(List.of(4));
+        expectedResult.add(List.of(3));
         expectedResult.add(Arrays.asList(2, 1, 0));
-        assertTrue(expectedResult.equals(actualResult));
+        assertEquals(expectedResult, actualResult);
     }
 
     @Test
-    public void findStronglyConnectedCompsShouldGetSingleNodes() {
-        // Create a adjacency list of graph
-        var n = 8;
+    public void testFindStronglyConnectedComponentsWithSingleNodes() {
+        // Create a graph where each node is its own SCC
+        int n = 8;
         var adjList = new ArrayList<List<Integer>>(n);
-
         for (int i = 0; i < n; i++) {
             adjList.add(new ArrayList<>());
         }
-
         adjList.get(0).add(1);
         adjList.get(1).add(2);
         adjList.get(2).add(3);
@@ -65,6 +62,71 @@ public void findStronglyConnectedCompsShouldGetSingleNodes() {
             7, 6, 5, 4, 3, 2, 1, 0
         */
         expectedResult.add(Arrays.asList(7, 6, 5, 4, 3, 2, 1, 0));
-        assertTrue(expectedResult.equals(actualResult));
+        assertEquals(expectedResult, actualResult);
+    }
+
+    @Test
+    public void testGraphWithMultipleSCCs() {
+        int v = 6;
+        var graph = new ArrayList<List<Integer>>();
+        for (int i = 0; i < v; i++) {
+            graph.add(new ArrayList<>());
+        }
+        graph.get(0).add(1);
+        graph.get(1).add(2);
+        graph.get(2).add(0);
+        graph.get(3).add(4);
+        graph.get(4).add(5);
+        graph.get(5).add(3);
+
+        var actualResult = tarjansAlgo.stronglyConnectedComponents(v, graph);
+        List<List<Integer>> expectedResult = new ArrayList<>();
+        expectedResult.add(Arrays.asList(2, 1, 0)); // SCC containing 0, 1, 2
+        expectedResult.add(Arrays.asList(5, 4, 3)); // SCC containing 3, 4, 5
+        assertEquals(expectedResult, actualResult);
+    }
+
+    @Test
+    public void testDisconnectedGraph() {
+        int v = 7;
+        var graph = new ArrayList<List<Integer>>();
+        for (int i = 0; i < v; i++) {
+            graph.add(new ArrayList<>());
+        }
+        graph.get(0).add(1);
+        graph.get(1).add(0);
+        graph.get(2).add(3);
+        graph.get(3).add(4);
+        graph.get(4).add(2);
+
+        var actualResult = tarjansAlgo.stronglyConnectedComponents(v, graph);
+        List<List<Integer>> expectedResult = new ArrayList<>();
+        expectedResult.add(Arrays.asList(1, 0)); // SCC containing 0, 1
+        expectedResult.add(Arrays.asList(4, 3, 2)); // SCC containing 2, 3, 4
+        expectedResult.add(List.of(5)); // SCC containing 5
+        expectedResult.add(List.of(6)); // SCC containing 6
+        assertEquals(expectedResult, actualResult);
+    }
+
+    @Test
+    public void testSingleNodeGraph() {
+        int v = 1;
+        var graph = new ArrayList<List<Integer>>();
+        graph.add(new ArrayList<>());
+
+        var actualResult = tarjansAlgo.stronglyConnectedComponents(v, graph);
+        List<List<Integer>> expectedResult = new ArrayList<>();
+        expectedResult.add(List.of(0)); // SCC with a single node
+        assertEquals(expectedResult, actualResult);
+    }
+
+    @Test
+    public void testEmptyGraph() {
+        int v = 0;
+        var graph = new ArrayList<List<Integer>>();
+
+        var actualResult = tarjansAlgo.stronglyConnectedComponents(v, graph);
+        List<List<Integer>> expectedResult = new ArrayList<>(); // No SCCs in an empty graph
+        assertEquals(expectedResult, actualResult);
     }
 }

From a8b84207161bf33358d899abd278f447890cf3f9 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 23:25:18 +0530
Subject: [PATCH 0686/1338] =?UTF-8?q?Enhance=20docs,=20remove=20`main`.=20?=
 =?UTF-8?q?add=20more=20tests=20in=20`HexaDecimal=E2=80=A6=20(#5923)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../conversions/HexaDecimalToDecimal.java     | 50 +++++++++++--------
 .../conversions/HexaDecimalToDecimalTest.java | 33 ++++++++++--
 2 files changed, 56 insertions(+), 27 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java b/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java
index 003781da9d5e..2cf6024d90a3 100644
--- a/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java
@@ -1,39 +1,45 @@
 package com.thealgorithms.conversions;
 
-import java.util.Scanner;
-
+/**
+ * Utility class for converting a hexadecimal string to its decimal representation.
+ * <p>
+ * A hexadecimal number uses the base-16 numeral system, with the following characters:
+ * <ul>
+ *   <li>Digits: 0-9</li>
+ *   <li>Letters: A-F (case-insensitive)</li>
+ * </ul>
+ * Each character represents a power of 16. For example:
+ * <pre>
+ *   Hexadecimal "A1" = 10*16^1 + 1*16^0 = 161 (decimal)
+ * </pre>
+ *
+ * <p>This class provides a method to perform the conversion without using built-in Java utilities.</p>
+ */
 public final class HexaDecimalToDecimal {
     private HexaDecimalToDecimal() {
     }
 
-    // convert hexadecimal to decimal
+    /**
+     * Converts a hexadecimal string to its decimal integer equivalent.
+     * <p>The input string is case-insensitive, and must contain valid hexadecimal characters [0-9, A-F].</p>
+     *
+     * @param hex the hexadecimal string to convert
+     * @return the decimal integer representation of the input hexadecimal string
+     * @throws IllegalArgumentException if the input string contains invalid characters
+     */
     public static int getHexaToDec(String hex) {
         String digits = "0123456789ABCDEF";
         hex = hex.toUpperCase();
         int val = 0;
+
         for (int i = 0; i < hex.length(); i++) {
             int d = digits.indexOf(hex.charAt(i));
+            if (d == -1) {
+                throw new IllegalArgumentException("Invalid hexadecimal character: " + hex.charAt(i));
+            }
             val = 16 * val + d;
         }
-        return val;
-    }
 
-    // Main method gets the hexadecimal input from user and converts it into Decimal output.
-    public static void main(String[] args) {
-        String hexaInput;
-        int decOutput;
-        Scanner scan = new Scanner(System.in);
-
-        System.out.print("Enter Hexadecimal Number : ");
-        hexaInput = scan.nextLine();
-
-        // convert hexadecimal to decimal
-        decOutput = getHexaToDec(hexaInput);
-        /*
-    Pass the string to the getHexaToDec function
-    and it returns the decimal form in the variable decOutput.
-         */
-        System.out.println("Number in Decimal: " + decOutput);
-        scan.close();
+        return val;
     }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/HexaDecimalToDecimalTest.java b/src/test/java/com/thealgorithms/conversions/HexaDecimalToDecimalTest.java
index c9c2ab2161ed..d0d6b400e299 100644
--- a/src/test/java/com/thealgorithms/conversions/HexaDecimalToDecimalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/HexaDecimalToDecimalTest.java
@@ -1,14 +1,37 @@
 package com.thealgorithms.conversions;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class HexaDecimalToDecimalTest {
 
-    @Test
-    public void testhexaDecimalToDecimal() {
-        assertEquals(161, HexaDecimalToDecimal.getHexaToDec("A1"));
-        assertEquals(428, HexaDecimalToDecimal.getHexaToDec("1ac"));
+    @ParameterizedTest
+    @CsvSource({
+        "A1, 161", // Simple case with two characters
+        "1AC, 428", // Mixed-case input
+        "0, 0", // Single zero
+        "F, 15", // Single digit
+        "10, 16", // Power of 16
+        "FFFF, 65535", // Max 4-character hex
+        "7FFFFFFF, 2147483647" // Max positive int value
+    })
+    public void
+    testValidHexaToDecimal(String hexInput, int expectedDecimal) {
+        assertEquals(expectedDecimal, HexaDecimalToDecimal.getHexaToDec(hexInput));
+    }
+
+    @ParameterizedTest
+    @CsvSource({
+        "G", // Invalid character
+        "1Z", // Mixed invalid input
+        "123G", // Valid prefix with invalid character
+        "#$%" // Non-hexadecimal symbols
+    })
+    public void
+    testInvalidHexaToDecimal(String invalidHex) {
+        assertThrows(IllegalArgumentException.class, () -> HexaDecimalToDecimal.getHexaToDec(invalidHex));
     }
 }

From cfa35a4fd9c3b2d450e8241055743d0d003a6b30 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 23:30:02 +0530
Subject: [PATCH 0687/1338] Add tests, fix `removeEdge` bug in `MatrixGraphs`
 (#5968)

---
 DIRECTORY.md                                  |   1 +
 .../datastructures/graphs/MatrixGraphs.java   |  28 ++--
 .../graphs/MatrixGraphsTest.java              | 140 ++++++++++++++++++
 3 files changed, 155 insertions(+), 14 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index f8bb3711a664..50f70abb2ed7 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -851,6 +851,7 @@
               * [KahnsAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithmTest.java)
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
               * [KruskalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java)
+              * [MatrixGraphsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java)
               * [TarjansAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
               * [WelshPowellTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java)
             * hashmap
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java b/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
index 902553f9a54c..c1d47df457da 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
@@ -102,7 +102,7 @@ public int numberOfVertices() {
     /**
      * Updates the number of edges in the graph
      *
-     * @param newNumberOfEdges
+     * @param newNumberOfEdges the new number of edges
      *
      */
     private void setNumberOfEdges(int newNumberOfEdges) {
@@ -202,7 +202,7 @@ public boolean addEdge(int from, int to) {
      * exists and is removed
      */
     public boolean removeEdge(int from, int to) {
-        if (!this.vertexDoesExist(from) || !this.vertexDoesExist(to)) {
+        if (this.vertexDoesExist(from) && this.vertexDoesExist(to)) {
             if (this.adjacencyOfEdgeDoesExist(from, to)) {
                 this.adjacency()[from][to] = AdjacencyMatrixGraph.EDGE_NONE;
                 this.adjacency()[to][from] = AdjacencyMatrixGraph.EDGE_NONE;
@@ -223,14 +223,14 @@ public boolean removeEdge(int from, int to) {
     public List<Integer> depthFirstOrder(int startVertex) {
         // If the startVertex is invalid, return an empty list
         if (startVertex >= vertexCount || startVertex < 0) {
-            return new ArrayList<Integer>();
+            return new ArrayList<>();
         }
 
         // Create an array to track the visited vertices
         boolean[] visited = new boolean[vertexCount];
 
         // Create a list to keep track of the order of our traversal
-        ArrayList<Integer> orderList = new ArrayList<Integer>();
+        ArrayList<Integer> orderList = new ArrayList<>();
 
         // Perform our DFS algorithm
         depthFirstOrder(startVertex, visited, orderList);
@@ -278,18 +278,18 @@ private void depthFirstOrder(int currentVertex, boolean[] visited, List<Integer>
     public List<Integer> breadthFirstOrder(int startVertex) {
         // If the specified startVertex is invalid, return an empty list
         if (startVertex >= vertexCount || startVertex < 0) {
-            return new ArrayList<Integer>();
+            return new ArrayList<>();
         }
 
         // Create an array to keep track of the visited vertices
         boolean[] visited = new boolean[vertexCount];
 
         // Create a list to keep track of the ordered vertices
-        ArrayList<Integer> orderList = new ArrayList<Integer>();
+        ArrayList<Integer> orderList = new ArrayList<>();
 
         // Create a queue for our BFS algorithm and add the startVertex
         // to the queue
-        Queue<Integer> queue = new LinkedList<Integer>();
+        Queue<Integer> queue = new LinkedList<>();
         queue.add(startVertex);
 
         // Continue until the queue is empty
@@ -327,19 +327,19 @@ public List<Integer> breadthFirstOrder(int startVertex) {
      * @return returns a string describing this graph
      */
     public String toString() {
-        String s = "    ";
+        StringBuilder s = new StringBuilder("    ");
         for (int i = 0; i < this.numberOfVertices(); i++) {
-            s = s + i + " ";
+            s.append(i).append(" ");
         }
-        s = s + " \n";
+        s.append(" \n");
 
         for (int i = 0; i < this.numberOfVertices(); i++) {
-            s = s + i + " : ";
+            s.append(i).append(" : ");
             for (int j = 0; j < this.numberOfVertices(); j++) {
-                s = s + this.adjMatrix[i][j] + " ";
+                s.append(this.adjMatrix[i][j]).append(" ");
             }
-            s = s + "\n";
+            s.append("\n");
         }
-        return s;
+        return s.toString();
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java
new file mode 100644
index 000000000000..cc8a2df872ce
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java
@@ -0,0 +1,140 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class MatrixGraphsTest {
+
+    @Test
+    void testGraphConstruction() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        assertEquals(5, graph.numberOfVertices());
+        assertEquals(0, graph.numberOfEdges());
+    }
+
+    @Test
+    void testAddEdge() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        assertTrue(graph.addEdge(0, 1));
+        assertTrue(graph.edgeDoesExist(0, 1));
+        assertTrue(graph.edgeDoesExist(1, 0));
+        assertEquals(1, graph.numberOfEdges());
+
+        // Adding the same edge again should return false
+        assertFalse(graph.addEdge(0, 1));
+        assertFalse(graph.addEdge(5, 1));
+        assertFalse(graph.addEdge(-1, 1));
+    }
+
+    @Test
+    void testRemoveEdge() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+
+        assertTrue(graph.removeEdge(0, 1));
+        assertFalse(graph.edgeDoesExist(0, 1));
+        assertFalse(graph.edgeDoesExist(1, 0));
+        assertEquals(1, graph.numberOfEdges());
+
+        assertFalse(graph.removeEdge(0, 3));
+        assertFalse(graph.removeEdge(5, 1));
+        assertFalse(graph.removeEdge(-1, 1));
+    }
+
+    @Test
+    void testVertexDoesExist() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        assertTrue(graph.vertexDoesExist(0));
+        assertTrue(graph.vertexDoesExist(4));
+        assertFalse(graph.vertexDoesExist(5));
+        assertFalse(graph.vertexDoesExist(-1));
+    }
+
+    @Test
+    void testDepthFirstOrder() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 2);
+        graph.addEdge(1, 3);
+        graph.addEdge(2, 4);
+
+        List<Integer> dfs = graph.depthFirstOrder(0);
+        assertEquals(5, dfs.size());
+        assertEquals(0, dfs.getFirst());
+
+        assertTrue(dfs.containsAll(Arrays.asList(0, 1, 2, 3, 4)));
+
+        List<Integer> emptyDfs = graph.depthFirstOrder(5);
+        assertTrue(emptyDfs.isEmpty());
+    }
+
+    @Test
+    void testBreadthFirstOrder() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 2);
+        graph.addEdge(1, 3);
+        graph.addEdge(2, 4);
+
+        List<Integer> bfs = graph.breadthFirstOrder(0);
+        assertEquals(5, bfs.size());
+        assertEquals(0, bfs.getFirst());
+
+        assertTrue(bfs.containsAll(Arrays.asList(0, 1, 2, 3, 4)));
+
+        List<Integer> emptyBfs = graph.breadthFirstOrder(5);
+        assertTrue(emptyBfs.isEmpty());
+    }
+
+    @Test
+    void testToString() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(3);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+
+        String expected = "    0 1 2  \n"
+            + "0 : 0 1 0 \n"
+            + "1 : 1 0 1 \n"
+            + "2 : 0 1 0 \n";
+
+        assertEquals(expected, graph.toString());
+    }
+
+    @Test
+    void testCyclicGraph() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(4);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 0);
+
+        List<Integer> dfs = graph.depthFirstOrder(0);
+        List<Integer> bfs = graph.breadthFirstOrder(0);
+
+        assertEquals(4, dfs.size());
+        assertEquals(4, bfs.size());
+        assertTrue(dfs.containsAll(Arrays.asList(0, 1, 2, 3)));
+        assertTrue(bfs.containsAll(Arrays.asList(0, 1, 2, 3)));
+    }
+
+    @Test
+    void testDisconnectedGraph() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(2, 3);
+
+        List<Integer> dfs = graph.depthFirstOrder(0);
+        List<Integer> bfs = graph.breadthFirstOrder(0);
+
+        assertEquals(2, dfs.size());
+        assertEquals(2, bfs.size());
+        assertTrue(dfs.containsAll(Arrays.asList(0, 1)));
+        assertTrue(bfs.containsAll(Arrays.asList(0, 1)));
+    }
+}

From ce3dd01e68aab58acb9f36dcea70f1477aff78e3 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 23:36:52 +0530
Subject: [PATCH 0688/1338] =?UTF-8?q?Enhance=20docs,=20remove=20`main`.=20?=
 =?UTF-8?q?add=20more=20tests=20in=20`HexaDecimal=E2=80=A6=20(#5922)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../conversions/HexaDecimalToBinary.java      | 73 ++++++++++++-------
 .../conversions/HexaDecimalToBinaryTest.java  | 42 +++++++++--
 2 files changed, 81 insertions(+), 34 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java b/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
index b6228488dc76..07acefc9fb14 100644
--- a/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
+++ b/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
@@ -1,43 +1,60 @@
 package com.thealgorithms.conversions;
 
-// Hex [0-9],[A-F] -> Binary [0,1]
+/**
+ * Utility class for converting hexadecimal numbers to binary representation.
+ * <p>
+ * A hexadecimal number consists of digits from {@code [0-9]} and {@code [A-F]} (case-insensitive),
+ * while binary representation uses only {@code [0, 1]}.
+ * <p>
+ * This class provides methods to:
+ * <ul>
+ *   <li>Convert a hexadecimal string to its binary string equivalent.</li>
+ *   <li>Ensure the binary output is padded to 8 bits (1 byte).</li>
+ * </ul>
+ * <p>
+ * Example:
+ * <ul>
+ *   <li>{@code "A1"} → {@code "10100001"}</li>
+ *   <li>{@code "1"} → {@code "00000001"}</li>
+ * </ul>
+ *
+ * <p>This class assumes that the input hexadecimal string is valid.</p>
+ */
 public class HexaDecimalToBinary {
+
+    /**
+     * Converts a hexadecimal string to its binary string equivalent.
+     * The binary output is padded to a minimum of 8 bits (1 byte).
+     * Steps:
+     * <ol>
+     *     <li>Convert the hexadecimal string to an integer.</li>
+     *     <li>Convert the integer to a binary string.</li>
+     *     <li>Pad the binary string to ensure it is at least 8 bits long.</li>
+     *     <li>Return the padded binary string.</li>
+     * </ol>
+     *
+     * @param numHex the hexadecimal string (e.g., "A1", "7F")
+     * @throws NumberFormatException if the input string is not a valid hexadecimal number
+     * @return the binary string representation, padded to 8 bits (e.g., "10100001")
+     */
     public String convert(String numHex) {
-        // String a HexaDecimal:
         int conHex = Integer.parseInt(numHex, 16);
-        // Hex a Binary:
         String binary = Integer.toBinaryString(conHex);
-        // Output:
         return completeDigits(binary);
     }
 
+    /**
+     * Pads the binary string to ensure it is at least 8 bits long.
+     * If the binary string is shorter than 8 bits, it adds leading zeros.
+     *
+     * @param binNum the binary string to pad
+     * @return the padded binary string with a minimum length of 8
+     */
     public String completeDigits(String binNum) {
-        final int longBits = 8;
-        for (int i = binNum.length(); i < longBits; i++) {
+        final int byteSize = 8;
+        while (binNum.length() < byteSize) {
             binNum = "0" + binNum;
         }
         return binNum;
     }
-
-    public static void main(String[] args) {
-        // Testing Numbers:
-        String[] hexNums = {
-            "1",
-            "A1",
-            "ef",
-            "BA",
-            "AA",
-            "BB",
-            "19",
-            "01",
-            "02",
-            "03",
-            "04",
-        };
-        HexaDecimalToBinary objConvert = new HexaDecimalToBinary();
-
-        for (String num : hexNums) {
-            System.out.println(num + " = " + objConvert.convert(num));
-        }
-    }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java b/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java
index 72a0a0174a93..1426eab64d2c 100644
--- a/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java
+++ b/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java
@@ -2,14 +2,44 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
+/**
+ * Unit tests for the {@link EndianConverter} class.
+ */
 public class HexaDecimalToBinaryTest {
 
-    @Test
-    public void testHexaDecimalToBinary() {
-        HexaDecimalToBinary hexaDecimalToBinary = new HexaDecimalToBinary();
-        assertEquals("1111111111111111111111111111111", hexaDecimalToBinary.convert("7fffffff"));
-        assertEquals("101010111100110111101111", hexaDecimalToBinary.convert("abcdef"));
+    /**
+     * Parameterized test to validate the conversion from little-endian to big-endian.
+     * Hexadecimal values are passed as strings and converted to integers during the test.
+     */
+    @ParameterizedTest
+    @CsvSource({
+        "0x78563412, 0x12345678", "0x00000000, 0x00000000", "0x00000001, 0x01000000",
+        "0xFFFFFFFF, 0xFFFFFFFF", // -1 in two's complement
+        "0x0000007F, 0x7F000000" // Positive boundary case
+    })
+    public void
+    testLittleToBigEndian(String inputHex, String expectedHex) {
+        int input = (int) Long.parseLong(inputHex.substring(2), 16); // Convert hex string to int
+        int expected = (int) Long.parseLong(expectedHex.substring(2), 16); // Convert hex string to int
+        assertEquals(expected, EndianConverter.littleToBigEndian(input));
+    }
+
+    /**
+     * Parameterized test to validate the conversion from big-endian to little-endian.
+     */
+    @ParameterizedTest
+    @CsvSource({
+        "0x12345678, 0x78563412", "0x00000000, 0x00000000", "0x01000000, 0x00000001",
+        "0xFFFFFFFF, 0xFFFFFFFF", // -1 in two's complement
+        "0x7F000000, 0x0000007F" // Positive boundary case
+    })
+    public void
+    testBigToLittleEndian(String inputHex, String expectedHex) {
+        int input = (int) Long.parseLong(inputHex.substring(2), 16); // Convert hex string to int
+        int expected = (int) Long.parseLong(expectedHex.substring(2), 16); // Convert hex string to int
+        assertEquals(expected, EndianConverter.bigToLittleEndian(input));
     }
 }

From 62c9309a3162081ec8345a2dcea9b6fd6a569ca1 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 26 Oct 2024 23:40:19 +0530
Subject: [PATCH 0689/1338] Enhance docs, remove `main`, add tests in `PrimMST`
 (#5969)

---
 DIRECTORY.md                                  |  1 +
 .../datastructures/graphs/PrimMST.java        | 83 ++++---------------
 .../datastructures/graphs/PrimMSTTest.java    | 54 ++++++++++++
 3 files changed, 72 insertions(+), 66 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/PrimMSTTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 50f70abb2ed7..833062d17d42 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -852,6 +852,7 @@
               * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
               * [KruskalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java)
               * [MatrixGraphsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java)
+              * [PrimMSTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/PrimMSTTest.java)
               * [TarjansAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
               * [WelshPowellTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java)
             * hashmap
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java b/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
index 7e11862786f6..8017c18ce6ac 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java
@@ -1,19 +1,17 @@
 package com.thealgorithms.datastructures.graphs;
 
 /**
- * A Java program for Prim's Minimum Spanning Tree (MST) algorithm. adjacency
- * matrix representation of the graph
+ * A Java program for Prim's Minimum Spanning Tree (MST) algorithm.
+ * Adjacency matrix representation of the graph.
  */
-class PrimMST {
+public class PrimMST {
 
     // Number of vertices in the graph
-
     private static final int V = 5;
 
-    // A utility function to find the vertex with minimum key
-    // value, from the set of vertices not yet included in MST
+    // A utility function to find the vertex with the minimum key
+    // value, from the set of vertices not yet included in the MST
     int minKey(int[] key, Boolean[] mstSet) {
-        // Initialize min value
         int min = Integer.MAX_VALUE;
         int minIndex = -1;
 
@@ -27,54 +25,30 @@ int minKey(int[] key, Boolean[] mstSet) {
         return minIndex;
     }
 
-    // A utility function to print the constructed MST stored in
-    // parent[]
-    void printMST(int[] parent, int n, int[][] graph) {
-        System.out.println("Edge   Weight");
-        for (int i = 1; i < V; i++) {
-            System.out.println(parent[i] + " - " + i + "    " + graph[i][parent[i]]);
-        }
-    }
-
-    // Function to construct and print MST for a graph represented
-    //  using adjacency matrix representation
-    void primMST(int[][] graph) {
-        // Array to store constructed MST
-        int[] parent = new int[V];
-
-        // Key values used to pick minimum weight edge in cut
-        int[] key = new int[V];
+    // Function to construct MST for a graph using adjacency matrix representation
+    public int[] primMST(int[][] graph) {
+        int[] parent = new int[V]; // Array to store constructed MST
+        int[] key = new int[V]; // Key values to pick minimum weight edge
+        Boolean[] mstSet = new Boolean[V]; // Vertices not yet included in MST
 
-        // To represent set of vertices not yet included in MST
-        Boolean[] mstSet = new Boolean[V];
-
-        // Initialize all keys as INFINITE
+        // Initialize all keys as INFINITE and mstSet[] as false
         for (int i = 0; i < V; i++) {
             key[i] = Integer.MAX_VALUE;
             mstSet[i] = Boolean.FALSE;
         }
 
-        // Always include first 1st vertex in MST.
-        key[0] = 0; // Make key 0 so that this vertex is
-        // picked as first vertex
+        // Always include the first vertex in MST
+        key[0] = 0; // Make key 0 to pick the first vertex
         parent[0] = -1; // First node is always root of MST
 
         // The MST will have V vertices
         for (int count = 0; count < V - 1; count++) {
-            // Pick thd minimum key vertex from the set of vertices
-            // not yet included in MST
+            // Pick the minimum key vertex not yet included in MST
             int u = minKey(key, mstSet);
-
-            // Add the picked vertex to the MST Set
             mstSet[u] = Boolean.TRUE;
 
-            // Update key value and parent index of the adjacent
-            // vertices of the picked vertex. Consider only those
-            // vertices which are not yet included in MST
-            for (int v = 0; v < V; v++) // Update the key only if graph[u][v] is smaller than key[v] // mstSet[v] is
-                                        // false for vertices not yet included in MST // graph[u][v] is non zero only
-                                        // for adjacent vertices of m
-            {
+            // Update key value and parent index of adjacent vertices of the picked vertex
+            for (int v = 0; v < V; v++) {
                 if (graph[u][v] != 0 && !mstSet[v] && graph[u][v] < key[v]) {
                     parent[v] = u;
                     key[v] = graph[u][v];
@@ -82,29 +56,6 @@ void primMST(int[][] graph) {
             }
         }
 
-        // print the constructed MST
-        printMST(parent, V, graph);
-    }
-
-    public static void main(String[] args) {
-        /* Let us create the following graph
-       2    3
-    (0)--(1)--(2)
-    |    / \   |
-    6| 8/   \5 |7
-    | /      \ |
-    (3)-------(4)
-         9          */
-        PrimMST t = new PrimMST();
-        int[][] graph = new int[][] {
-            {0, 2, 0, 6, 0},
-            {2, 0, 3, 8, 5},
-            {0, 3, 0, 0, 7},
-            {6, 8, 0, 0, 9},
-            {0, 5, 7, 9, 0},
-        };
-
-        // Print the solution
-        t.primMST(graph);
+        return parent; // Return the MST parent array
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/PrimMSTTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/PrimMSTTest.java
new file mode 100644
index 000000000000..ec59a3880642
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/PrimMSTTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class PrimMSTTest {
+
+    private final PrimMST primMST = new PrimMST();
+
+    @Test
+    public void testSimpleGraph() {
+        // Test graph with 5 nodes and weighted edges
+        int[][] graph = {{0, 2, 0, 6, 0}, {2, 0, 3, 8, 5}, {0, 3, 0, 0, 7}, {6, 8, 0, 0, 9}, {0, 5, 7, 9, 0}};
+
+        int[] expectedParent = {-1, 0, 1, 0, 1};
+        int[] actualParent = primMST.primMST(graph);
+
+        assertArrayEquals(expectedParent, actualParent);
+    }
+
+    @Test
+    public void testDisconnectedGraph() {
+        // Test case with a disconnected graph (no valid MST)
+        int[][] graph = {{0, 1, 0, 0, 0}, {1, 0, 2, 0, 0}, {0, 2, 0, 3, 0}, {0, 0, 3, 0, 4}, {0, 0, 0, 4, 0}};
+
+        int[] expectedParent = {-1, 0, 1, 2, 3}; // Expected MST parent array
+        int[] actualParent = primMST.primMST(graph);
+
+        assertArrayEquals(expectedParent, actualParent);
+    }
+
+    @Test
+    public void testAllEqualWeightsGraph() {
+        // Test case where all edges have equal weight
+        int[][] graph = {{0, 1, 1, 1, 1}, {1, 0, 1, 1, 1}, {1, 1, 0, 1, 1}, {1, 1, 1, 0, 1}, {1, 1, 1, 1, 0}};
+
+        int[] expectedParent = {-1, 0, 0, 0, 0}; // Expected MST parent array (any valid spanning tree)
+        int[] actualParent = primMST.primMST(graph);
+
+        assertArrayEquals(expectedParent, actualParent);
+    }
+
+    @Test
+    public void testSparseGraph() {
+        // Test case with a sparse graph (few edges)
+        int[][] graph = {{0, 1, 0, 0, 0}, {1, 0, 1, 0, 0}, {0, 1, 0, 1, 0}, {0, 0, 1, 0, 1}, {0, 0, 0, 1, 0}};
+
+        int[] expectedParent = {-1, 0, 1, 2, 3}; // Expected MST parent array
+        int[] actualParent = primMST.primMST(graph);
+
+        assertArrayEquals(expectedParent, actualParent);
+    }
+}

From b5a097c56a926028dea4459492a9a3abdce1be51 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 27 Oct 2024 00:05:36 +0530
Subject: [PATCH 0690/1338] Enhance docs, add more tests in `EndianConverter`
 (#5921)

---
 .../conversions/EndianConverter.java          | 32 ++++++++++++++---
 .../conversions/EndianConverterTest.java      | 35 +++++++++++++------
 2 files changed, 52 insertions(+), 15 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/EndianConverter.java b/src/main/java/com/thealgorithms/conversions/EndianConverter.java
index d20d9d6d63b5..0d69098e8255 100644
--- a/src/main/java/com/thealgorithms/conversions/EndianConverter.java
+++ b/src/main/java/com/thealgorithms/conversions/EndianConverter.java
@@ -1,11 +1,23 @@
 package com.thealgorithms.conversions;
 
 /**
- * Converts between big-endian and little-endian formats.
- * Big-endian is the most significant byte first, while little-endian is the least significant byte first.
- * Big-endian to little-endian: 0x12345678 -> 0x78563412
+ * Utility class for converting integers between big-endian and little-endian formats.
+ * <p>
+ * Endianness defines how byte sequences represent multi-byte data types:
+ * <ul>
+ *   <li><b>Big-endian</b>: The most significant byte (MSB) comes first.</li>
+ *   <li><b>Little-endian</b>: The least significant byte (LSB) comes first.</li>
+ * </ul>
+ * <p>
+ * Example conversion:
+ * <ul>
+ *   <li>Big-endian to little-endian: {@code 0x12345678} → {@code 0x78563412}</li>
+ *   <li>Little-endian to big-endian: {@code 0x78563412} → {@code 0x12345678}</li>
+ * </ul>
  *
- * Little-endian to big-endian: 0x12345678 -> 0x78563412
+ * <p>Note: Both conversions in this utility are equivalent since reversing the bytes is symmetric.</p>
+ *
+ * <p>This class only supports 32-bit integers.</p>
  *
  * @author Hardvan
  */
@@ -13,10 +25,22 @@ public final class EndianConverter {
     private EndianConverter() {
     }
 
+    /**
+     * Converts a 32-bit integer from big-endian to little-endian.
+     *
+     * @param value the integer in big-endian format
+     * @return the integer in little-endian format
+     */
     public static int bigToLittleEndian(int value) {
         return Integer.reverseBytes(value);
     }
 
+    /**
+     * Converts a 32-bit integer from little-endian to big-endian.
+     *
+     * @param value the integer in little-endian format
+     * @return the integer in big-endian format
+     */
     public static int littleToBigEndian(int value) {
         return Integer.reverseBytes(value);
     }
diff --git a/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java b/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java
index 9598dd163146..85ffa2190962 100644
--- a/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java
+++ b/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java
@@ -2,21 +2,34 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class EndianConverterTest {
 
-    @Test
-    public void testBigToLittleEndian() {
-        assertEquals(0x78563412, EndianConverter.bigToLittleEndian(0x12345678));
-        assertEquals(0x00000000, EndianConverter.bigToLittleEndian(0x00000000));
-        assertEquals(0x00000001, EndianConverter.bigToLittleEndian(0x01000000));
+    @ParameterizedTest
+    @CsvSource({
+        "0x78563412, 0x12345678", "0x00000000, 0x00000000", "0x00000001, 0x01000000",
+        "0xFFFFFFFF, 0xFFFFFFFF", // -1 in two's complement
+        "0x0000007F, 0x7F000000" // Positive boundary case
+    })
+    public void
+    testLittleToBigEndian(String inputHex, String expectedHex) {
+        int input = (int) Long.parseLong(inputHex.substring(2), 16); // Convert hex string to int
+        int expected = (int) Long.parseLong(expectedHex.substring(2), 16); // Convert hex string to int
+        assertEquals(expected, EndianConverter.littleToBigEndian(input));
     }
 
-    @Test
-    public void testLittleToBigEndian() {
-        assertEquals(0x12345678, EndianConverter.littleToBigEndian(0x78563412));
-        assertEquals(0x00000000, EndianConverter.littleToBigEndian(0x00000000));
-        assertEquals(0x01000000, EndianConverter.littleToBigEndian(0x00000001));
+    @ParameterizedTest
+    @CsvSource({
+        "0x12345678, 0x78563412", "0x00000000, 0x00000000", "0x01000000, 0x00000001",
+        "0xFFFFFFFF, 0xFFFFFFFF", // -1 in two's complement
+        "0x7F000000, 0x0000007F" // Positive boundary case
+    })
+    public void
+    testBigToLittleEndian(String inputHex, String expectedHex) {
+        int input = (int) Long.parseLong(inputHex.substring(2), 16); // Convert hex string to int
+        int expected = (int) Long.parseLong(expectedHex.substring(2), 16); // Convert hex string to int
+        assertEquals(expected, EndianConverter.bigToLittleEndian(input));
     }
 }

From e6f70634a48ba9e6061a8639e47f74a76dfc2397 Mon Sep 17 00:00:00 2001
From: Giulio Tantaro <giulio.tantaro@gmail.com>
Date: Sat, 26 Oct 2024 20:39:23 +0200
Subject: [PATCH 0691/1338] Cleanup combination and combination test (#5902)

---
 .../backtracking/Combination.java             | 25 +++++++++++--------
 .../backtracking/CombinationTest.java         | 22 +++++++++++++++-
 2 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/Combination.java b/src/main/java/com/thealgorithms/backtracking/Combination.java
index bf2a672a0ef8..ecaf7428f986 100644
--- a/src/main/java/com/thealgorithms/backtracking/Combination.java
+++ b/src/main/java/com/thealgorithms/backtracking/Combination.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.backtracking;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.TreeSet;
@@ -13,8 +14,6 @@ public final class Combination {
     private Combination() {
     }
 
-    private static int length;
-
     /**
      * Find all combinations of given array using backtracking
      * @param arr the array.
@@ -23,39 +22,45 @@ private Combination() {
      * @return a list of all combinations of length n. If n == 0, return null.
      */
     public static <T> List<TreeSet<T>> combination(T[] arr, int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("The combination length cannot be negative.");
+        }
+
         if (n == 0) {
-            return null;
+            return Collections.emptyList();
         }
-        length = n;
         T[] array = arr.clone();
         Arrays.sort(array);
+
         List<TreeSet<T>> result = new LinkedList<>();
-        backtracking(array, 0, new TreeSet<T>(), result);
+        backtracking(array, n, 0, new TreeSet<T>(), result);
         return result;
     }
 
     /**
      * Backtrack all possible combinations of a given array
      * @param arr the array.
+     * @param n length of the combination
      * @param index the starting index.
      * @param currSet set that tracks current combination
      * @param result the list contains all combination.
      * @param <T> the type of elements in the array.
      */
-    private static <T> void backtracking(T[] arr, int index, TreeSet<T> currSet, List<TreeSet<T>> result) {
-        if (index + length - currSet.size() > arr.length) {
+    private static <T> void backtracking(T[] arr, int n, int index, TreeSet<T> currSet, List<TreeSet<T>> result) {
+        if (index + n - currSet.size() > arr.length) {
             return;
         }
-        if (length - 1 == currSet.size()) {
+        if (currSet.size() == n - 1) {
             for (int i = index; i < arr.length; i++) {
                 currSet.add(arr[i]);
-                result.add((TreeSet<T>) currSet.clone());
+                result.add(new TreeSet<>(currSet));
                 currSet.remove(arr[i]);
             }
+            return;
         }
         for (int i = index; i < arr.length; i++) {
             currSet.add(arr[i]);
-            backtracking(arr, i + 1, currSet, result);
+            backtracking(arr, n, i + 1, currSet, result);
             currSet.remove(arr[i]);
         }
     }
diff --git a/src/test/java/com/thealgorithms/backtracking/CombinationTest.java b/src/test/java/com/thealgorithms/backtracking/CombinationTest.java
index 44edc3077fd5..a9d1163f3ecd 100644
--- a/src/test/java/com/thealgorithms/backtracking/CombinationTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/CombinationTest.java
@@ -1,17 +1,28 @@
 package com.thealgorithms.backtracking;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
+import java.util.Set;
 import java.util.TreeSet;
 import org.junit.jupiter.api.Test;
 
 public class CombinationTest {
 
+    @Test
+    void testNegativeElement() {
+        Integer[] array = {1, 2};
+        assertThrows(IllegalArgumentException.class, () -> { Combination.combination(array, -1); });
+    }
+
     @Test
     void testNoElement() {
         List<TreeSet<Integer>> result = Combination.combination(new Integer[] {1, 2}, 0);
-        assertTrue(result == null);
+        assertNotNull(result);
+        assertEquals(0, result.size());
     }
 
     @Test
@@ -28,4 +39,13 @@ void testLengthTwo() {
         assertTrue(arr[0] == 1);
         assertTrue(arr[1] == 2);
     }
+
+    @Test
+    void testCombinationsWithStrings() {
+        List<TreeSet<String>> result = Combination.combination(new String[] {"a", "b", "c"}, 2);
+        assertEquals(3, result.size());
+        assertTrue(result.contains(new TreeSet<>(Set.of("a", "b"))));
+        assertTrue(result.contains(new TreeSet<>(Set.of("a", "c"))));
+        assertTrue(result.contains(new TreeSet<>(Set.of("b", "c"))));
+    }
 }

From 8b604858f531e9878613e8ef5fb9f99132afb436 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 27 Oct 2024 00:20:31 +0530
Subject: [PATCH 0692/1338] Enhance docs, add more tests in `Vigenere` (#5899)

---
 .../com/thealgorithms/ciphers/Vigenere.java   | 67 ++++++++++++++++--
 .../thealgorithms/ciphers/VigenereTest.java   | 70 +++++++++++++++----
 2 files changed, 118 insertions(+), 19 deletions(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/Vigenere.java b/src/main/java/com/thealgorithms/ciphers/Vigenere.java
index 1702f1abb94c..0f117853bb85 100644
--- a/src/main/java/com/thealgorithms/ciphers/Vigenere.java
+++ b/src/main/java/com/thealgorithms/ciphers/Vigenere.java
@@ -1,16 +1,54 @@
 package com.thealgorithms.ciphers;
 
 /**
- * A Java implementation of Vigenere Cipher.
+ * A Java implementation of the Vigenère Cipher.
+ *
+ * The Vigenère Cipher is a polyalphabetic substitution cipher that uses a
+ * keyword to shift letters in the plaintext by different amounts, depending
+ * on the corresponding character in the keyword. It wraps around the alphabet,
+ * ensuring the shifts are within 'A'-'Z' or 'a'-'z'.
+ *
+ * Non-alphabetic characters (like spaces, punctuation) are kept unchanged.
+ *
+ * Encryption Example:
+ * - Plaintext: "Hello World!"
+ * - Key: "suchsecret"
+ * - Encrypted Text: "Zynsg Yfvev!"
+ *
+ * Decryption Example:
+ * - Ciphertext: "Zynsg Yfvev!"
+ * - Key: "suchsecret"
+ * - Decrypted Text: "Hello World!"
+ *
+ * Wikipedia Reference:
+ * <a href="https://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher">Vigenère Cipher - Wikipedia</a>
  *
  * @author straiffix
  * @author beingmartinbmc
  */
 public class Vigenere {
 
+    /**
+     * Encrypts a given message using the Vigenère Cipher with the specified key.
+     * Steps:
+     * 1. Iterate over each character in the message.
+     * 2. If the character is a letter, shift it by the corresponding character in the key.
+     * 3. Preserve the case of the letter.
+     * 4. Preserve non-alphabetic characters.
+     * 5. Move to the next character in the key (cyclic).
+     * 6. Return the encrypted message.
+     *
+     * @param message The plaintext message to encrypt.
+     * @param key The keyword used for encryption.
+     * @throws IllegalArgumentException if the key is empty.
+     * @return The encrypted message.
+     */
     public String encrypt(final String message, final String key) {
-        StringBuilder result = new StringBuilder();
+        if (key.isEmpty()) {
+            throw new IllegalArgumentException("Key cannot be empty.");
+        }
 
+        StringBuilder result = new StringBuilder();
         int j = 0;
         for (int i = 0; i < message.length(); i++) {
             char c = message.charAt(i);
@@ -20,17 +58,35 @@ public String encrypt(final String message, final String key) {
                 } else {
                     result.append((char) ((c + key.toLowerCase().charAt(j) - 2 * 'a') % 26 + 'a'));
                 }
+                j = ++j % key.length();
             } else {
                 result.append(c);
             }
-            j = ++j % key.length();
         }
         return result.toString();
     }
 
+    /**
+     * Decrypts a given message encrypted with the Vigenère Cipher using the specified key.
+     * Steps:
+     * 1. Iterate over each character in the message.
+     * 2. If the character is a letter, shift it back by the corresponding character in the key.
+     * 3. Preserve the case of the letter.
+     * 4. Preserve non-alphabetic characters.
+     * 5. Move to the next character in the key (cyclic).
+     * 6. Return the decrypted message.
+     *
+     * @param message The encrypted message to decrypt.
+     * @param key The keyword used for decryption.
+     * @throws IllegalArgumentException if the key is empty.
+     * @return The decrypted plaintext message.
+     */
     public String decrypt(final String message, final String key) {
-        StringBuilder result = new StringBuilder();
+        if (key.isEmpty()) {
+            throw new IllegalArgumentException("Key cannot be empty.");
+        }
 
+        StringBuilder result = new StringBuilder();
         int j = 0;
         for (int i = 0; i < message.length(); i++) {
             char c = message.charAt(i);
@@ -40,11 +96,10 @@ public String decrypt(final String message, final String key) {
                 } else {
                     result.append((char) ('z' - (25 - (c - key.toLowerCase().charAt(j))) % 26));
                 }
+                j = ++j % key.length();
             } else {
                 result.append(c);
             }
-
-            j = ++j % key.length();
         }
         return result.toString();
     }
diff --git a/src/test/java/com/thealgorithms/ciphers/VigenereTest.java b/src/test/java/com/thealgorithms/ciphers/VigenereTest.java
index c5935de95dfa..7f94e5731989 100644
--- a/src/test/java/com/thealgorithms/ciphers/VigenereTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/VigenereTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.ciphers;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
@@ -9,28 +10,71 @@ class VigenereTest {
     Vigenere vigenere = new Vigenere();
 
     @Test
-    void vigenereEncryptTest() {
-        // given
+    void testVigenereEncryptDecrypt() {
         String text = "Hello World!";
         String key = "suchsecret";
 
-        // when
-        String cipherText = vigenere.encrypt(text, key);
+        String encryptedText = vigenere.encrypt(text, key);
+        String decryptedText = vigenere.decrypt(encryptedText, key);
 
-        // then
-        assertEquals("Zynsg Yfvev!", cipherText);
+        assertEquals("Zynsg Aqipw!", encryptedText);
+        assertEquals("Hello World!", decryptedText);
     }
 
     @Test
-    void vigenereDecryptTest() {
-        // given
-        String encryptedText = "Zynsg Yfvev!";
-        String key = "suchsecret";
+    void testWithEmptyMessage() {
+        String text = "";
+        String key = "anykey";
 
-        // when
+        String encryptedText = vigenere.encrypt(text, key);
         String decryptedText = vigenere.decrypt(encryptedText, key);
 
-        // then
-        assertEquals("Hello World!", decryptedText);
+        assertEquals("", encryptedText);
+        assertEquals("", decryptedText);
+    }
+
+    @Test
+    void testWithEmptyKey() {
+        String text = "This should remain the same";
+        String key = "";
+
+        assertThrows(IllegalArgumentException.class, () -> vigenere.encrypt(text, key));
+        assertThrows(IllegalArgumentException.class, () -> vigenere.decrypt(text, key));
+    }
+
+    @Test
+    void testWithNumbersInMessage() {
+        String text = "Vigenere123!";
+        String key = "cipher";
+
+        String encryptedText = vigenere.encrypt(text, key);
+        String decryptedText = vigenere.decrypt(encryptedText, key);
+
+        assertEquals("Xqvlrvtm123!", encryptedText);
+        assertEquals(text, decryptedText);
+    }
+
+    @Test
+    void testLongerKeyThanMessage() {
+        String text = "Short";
+        String key = "VeryLongSecretKey";
+
+        String encryptedText = vigenere.encrypt(text, key);
+        String decryptedText = vigenere.decrypt(encryptedText, key);
+
+        assertEquals("Nlfpe", encryptedText);
+        assertEquals(text, decryptedText);
+    }
+
+    @Test
+    void testUppercaseMessageAndKey() {
+        String text = "HELLO";
+        String key = "SECRET";
+
+        String encryptedText = vigenere.encrypt(text, key);
+        String decryptedText = vigenere.decrypt(encryptedText, key);
+
+        assertEquals("ZINCS", encryptedText);
+        assertEquals(text, decryptedText);
     }
 }

From 84522baa9247b1c7ab3d5a5fa81ea02e6fa9db85 Mon Sep 17 00:00:00 2001
From: Ayush Majumder <126413422+dynoayush@users.noreply.github.com>
Date: Sun, 27 Oct 2024 00:25:41 +0530
Subject: [PATCH 0693/1338] Update README.md and add some description (#5886)

---
 .../datastructures/graphs/README.md           | 37 ++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/README.md b/src/main/java/com/thealgorithms/datastructures/graphs/README.md
index 057adb46acf5..4798e372667b 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/README.md
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/README.md
@@ -88,4 +88,39 @@ It means there are edges from 0 to 1, 2, and 3; from 1 to 0 and 2, and so on.
 2  1 1 0 0 0
 3  1 0 0 0 1
 4  0 0 0 1 0
-```
+
+###Graph Terminologies
+
+Degree of a vertex: Number of edges that are incident at a vertex.
+Weighted graph: A graph that has weights assigned for each of the edges (used in cases such as shortest path problems).
+Connected components: A set of vertices that can reach others from it but not to those outside this connected component.
+Cycle: A path that begins and ends at the same vertex.
+Bipartite Graph: A graph whose vertices can be partitioned into two disjoint sets, with every edge connecting a vertex in one set to a vertex in the other set.
+
+###Graph Algorithms
+
+Breadth-First Search: It explores neighbors in layer after layer and applies on shortest path problems for unweighted graphs.
+Depth-First Search (DFS): It continues moving up as far along each branch as possible before backtracking. DFS is typically used for traversing all nodes and testing connectivity.
+Dijkstra's Algorithm: This algorithm finds the shortest path from a single starting vertex to all other vertices in a weighted graph.
+Prim's and Kruskal's Algorithm: To find the minimum spanning tree.
+Bellman-Ford Algorithm: This algorithm solves shortest path problems even when there are negative weights.
+Graph Types
+Multigraphs: Graphs with more edges between the same set of vertices.
+Complete Graphs: A graph in which there is a unique edge between each pair of vertices.
+Planar Graphs: A graph that can be drawn in a plane such that no two edges cross.
+
+###Graph Algorithm Applications
+
+Google Maps (Dijkstra's Algorithm): How maps apps find shortest routes.
+Job Scheduling: Topological Sort A real application of DAG (Directed Acyclic Graph) to manage the dependency of jobs between tasks.
+Web Crawling: How to use BFS for web crawlers to index pages in search engines.
+Big-O Complexity of Graph Operations
+Adjacency List vs Adjacency Matrix : Provide comparison tables of time complexity for operations such as addition of an edge, checking if an edge exists, etc.
+BFS and DFS Complexity : Describe their computational cost
+
+###Common Graph Problems
+
+Graph Coloring 
+Finding Bridges and Articulation Points 
+Finding Strongly Connected Components 
+Maximum Flow (Ford-Fulkerson algorithm)

From 3da16a7fe05bfa69afc57475263e9031c6776b72 Mon Sep 17 00:00:00 2001
From: "Ramit Gangwar (NoiR)" <54339318+TheDarkW3b@users.noreply.github.com>
Date: Sun, 27 Oct 2024 00:31:47 +0530
Subject: [PATCH 0694/1338] Add LongestCommonPrefix (#5849)

---
 DIRECTORY.md                                  |  2 +
 .../strings/LongestCommonPrefix.java          | 22 ++++++
 .../strings/LongestCommonPrefixTest.java      | 73 +++++++++++++++++++
 3 files changed, 97 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java
 create mode 100644 src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 833062d17d42..ac2e921e6081 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -686,6 +686,7 @@
             * [Isomorphic](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Isomorphic.java)
             * [KMP](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/KMP.java)
             * [LetterCombinationsOfPhoneNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java)
+            * [LongestCommonPrefix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java)
             * [LongestNonRepetitiveSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java)
             * [LongestPalindromicSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java)
             * [Lower](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Lower.java)
@@ -1311,6 +1312,7 @@
             * [HorspoolSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java)
             * [IsomorphicTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/IsomorphicTest.java)
             * [LetterCombinationsOfPhoneNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java)
+            * [LongestCommonPrefixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java)
             * [LongestNonRepetitiveSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java)
             * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java)
             * [LowerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LowerTest.java)
diff --git a/src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java b/src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java
new file mode 100644
index 000000000000..0fabdaa2658b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.strings;
+
+import java.util.Arrays;
+
+public final class LongestCommonPrefix {
+    public String longestCommonPrefix(String[] strs) {
+        if (strs == null || strs.length == 0) {
+            return "";
+        }
+
+        Arrays.sort(strs);
+        String shortest = strs[0];
+        String longest = strs[strs.length - 1];
+
+        int index = 0;
+        while (index < shortest.length() && index < longest.length() && shortest.charAt(index) == longest.charAt(index)) {
+            index++;
+        }
+
+        return shortest.substring(0, index);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java b/src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java
new file mode 100644
index 000000000000..580a2726d285
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java
@@ -0,0 +1,73 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class LongestCommonPrefixTest {
+
+    private final LongestCommonPrefix longestCommonPrefix = new LongestCommonPrefix();
+
+    @Test
+    public void testCommonPrefix() {
+        String[] input = {"flower", "flow", "flight"};
+        String expected = "fl";
+        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    }
+
+    @Test
+    public void testNoCommonPrefix() {
+        String[] input = {"dog", "racecar", "car"};
+        String expected = "";
+        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    }
+
+    @Test
+    public void testEmptyArray() {
+        String[] input = {};
+        String expected = "";
+        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    }
+
+    @Test
+    public void testNullArray() {
+        String[] input = null;
+        String expected = "";
+        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    }
+
+    @Test
+    public void testSingleString() {
+        String[] input = {"single"};
+        String expected = "single";
+        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    }
+
+    @Test
+    public void testCommonPrefixWithDifferentLengths() {
+        String[] input = {"ab", "a"};
+        String expected = "a";
+        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    }
+
+    @Test
+    public void testAllSameStrings() {
+        String[] input = {"test", "test", "test"};
+        String expected = "test";
+        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    }
+
+    @Test
+    public void testPrefixAtEnd() {
+        String[] input = {"abcde", "abcfgh", "abcmnop"};
+        String expected = "abc";
+        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    }
+
+    @Test
+    public void testMixedCase() {
+        String[] input = {"Flower", "flow", "flight"};
+        String expected = "";
+        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    }
+}

From 985c1f9dd110cd4dcaed04573a3e2922b416502f Mon Sep 17 00:00:00 2001
From: pranayh24 <121727121+pranayh24@users.noreply.github.com>
Date: Sun, 27 Oct 2024 00:35:14 +0530
Subject: [PATCH 0695/1338] Add Maximum Sliding Window algorithm (#5848)

---
 .../others/MaximumSlidingWindow.java          | 56 +++++++++++++++++
 .../others/MaximumSlidingWindowTest.java      | 63 +++++++++++++++++++
 2 files changed, 119 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java
 create mode 100644 src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java

diff --git a/src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java b/src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java
new file mode 100644
index 000000000000..d0b2c2a0e56d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.others;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+
+/**
+ * Maximum Sliding Window Algorithm
+ *
+ * This algorithm finds the maximum element in each sliding window of size k
+ * in a given array of integers. It uses a deque (double-ended queue) to
+ * efficiently keep track of potential maximum values in the current window.
+ *
+ * Time Complexity: O(n), where n is the number of elements in the input array
+ * Space Complexity: O(k), where k is the size of the sliding window
+ */
+
+public class MaximumSlidingWindow {
+
+    /**
+     * Finds the maximum values in each sliding window of size k.
+     *
+     * @param nums The input array of integers
+     * @param windowSize The size of the sliding window
+     * @return An array of integers representing the maximums in each window
+     */
+    public int[] maxSlidingWindow(int[] nums, int windowSize) {
+        if (nums == null || nums.length == 0 || windowSize <= 0 || windowSize > nums.length) {
+            return new int[0]; // Handle edge cases
+        }
+
+        int[] result = new int[nums.length - windowSize + 1];
+        Deque<Integer> deque = new ArrayDeque<>();
+
+        for (int currentIndex = 0; currentIndex < nums.length; currentIndex++) {
+
+            // Remove the first element if it's outside the current window
+            if (!deque.isEmpty() && deque.peekFirst() == currentIndex - windowSize) {
+                deque.pollFirst();
+            }
+
+            // Remove all elements smaller than the current element from the end
+            while (!deque.isEmpty() && nums[deque.peekLast()] < nums[currentIndex]) {
+                deque.pollLast();
+            }
+
+            // Add the current element's index to the deque
+            deque.offerLast(currentIndex);
+
+            // If we have processed at least k elements, add to result
+            if (currentIndex >= windowSize - 1) {
+                result[currentIndex - windowSize + 1] = nums[deque.peekFirst()];
+            }
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java b/src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java
new file mode 100644
index 000000000000..9209136a5af3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java
@@ -0,0 +1,63 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class MaximumSlidingWindowTest {
+
+    MaximumSlidingWindow msw;
+    int[] nums;
+    int k;
+
+    @BeforeEach
+    void setUp() {
+        msw = new MaximumSlidingWindow(); // Initialize the MaximumSlidingWindow object
+    }
+
+    // Test for a simple sliding window case
+    @Test
+    void testMaxSlidingWindowSimpleCase() {
+        nums = new int[] {1, 3, -1, -3, 5, 3, 6, 7};
+        k = 3;
+        int[] expected = {3, 3, 5, 5, 6, 7};
+        assertArrayEquals(expected, msw.maxSlidingWindow(nums, k));
+    }
+
+    // Test when window size is 1 (output should be the array itself)
+    @Test
+    void testMaxSlidingWindowWindowSizeOne() {
+        nums = new int[] {4, 2, 12, 11, -5};
+        k = 1;
+        int[] expected = {4, 2, 12, 11, -5};
+        assertArrayEquals(expected, msw.maxSlidingWindow(nums, k));
+    }
+
+    // Test when the window size is equal to the array length (output should be a single max element)
+    @Test
+    void testMaxSlidingWindowWindowSizeEqualsArrayLength() {
+        nums = new int[] {4, 2, 12, 11, -5};
+        k = nums.length;
+        int[] expected = {12}; // Maximum of the entire array
+        assertArrayEquals(expected, msw.maxSlidingWindow(nums, k));
+    }
+
+    // Test when the input array is empty
+    @Test
+    void testMaxSlidingWindowEmptyArray() {
+        nums = new int[] {};
+        k = 3;
+        int[] expected = {};
+        assertArrayEquals(expected, msw.maxSlidingWindow(nums, k));
+    }
+
+    // Test when the window size is larger than the array (should return empty)
+    @Test
+    void testMaxSlidingWindowWindowSizeLargerThanArray() {
+        nums = new int[] {1, 2, 3};
+        k = 5;
+        int[] expected = {}; // Window size is too large, so no result
+        assertArrayEquals(expected, msw.maxSlidingWindow(nums, k));
+    }
+}

From d4a13fc8b583041bdaf59ab377e95f8ba9f0dc1a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 27 Oct 2024 00:43:57 +0530
Subject: [PATCH 0696/1338] =?UTF-8?q?Enhance=20docs,=20remove=20`main`,=20?=
 =?UTF-8?q?add=20tests=20in=20`SearchSinglyLink=E2=80=A6=20(#6012)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 DIRECTORY.md                                  |  3 +
 .../SearchSinglyLinkedListRecursion.java      | 48 ++++++----
 .../SearchSinglyLinkedListRecursionTest.java  | 89 +++++++++++++++++++
 3 files changed, 123 insertions(+), 17 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index ac2e921e6081..0c9aeca4e59a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -520,6 +520,7 @@
             * [LowestBasePalindrome](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java)
             * [Luhn](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Luhn.java)
             * [Mandelbrot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Mandelbrot.java)
+            * [MaximumSlidingWindow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java)
             * [MaximumSumOfDistinctSubarraysWithLengthK](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java)
             * [MemoryManagementAlgorithms](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java)
             * [MiniMaxAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java)
@@ -887,6 +888,7 @@
               * [QuickSortLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java)
               * [ReverseKGroupTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java)
               * [RotateSinglyLinkedListsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java)
+              * [SearchSinglyLinkedListRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursionTest.java)
               * [SinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java)
               * [SkipListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java)
               * [SortedLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java)
@@ -1151,6 +1153,7 @@
             * [LineSweepTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/LineSweepTest.java)
             * [LinkListSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/LinkListSortTest.java)
             * [LowestBasePalindromeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java)
+            * [MaximumSlidingWindowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java)
             * [MaximumSumOfDistinctSubarraysWithLengthKTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java)
             * [NewManShanksPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java)
             * [NextFitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/NextFitTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java b/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java
index 35f8c9a95b56..a40e9b2a1a66 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java
@@ -1,31 +1,45 @@
 package com.thealgorithms.datastructures.lists;
 
+/**
+ * The SearchSinglyLinkedListRecursion class extends SinglyLinkedList and provides
+ * a method to search for a value in a singly linked list using recursion.
+ * <p>
+ * This class demonstrates a recursive approach to check if a given integer value is
+ * present in the linked list. The search method calls a private recursive helper method
+ * `searchRecursion`, which checks each node's value and moves to the next node if necessary.
+ * </p>
+ * <p>
+ * Example:
+ * Given a list containing the values 1 -> 2 -> 3 -> 4, calling search(3) will return `true`,
+ * while calling search(5) will return `false`.
+ * </p>
+ * <p>
+ * Complexity:
+ * <ul>
+ *   <li>Time Complexity: O(n), where n is the number of nodes in the linked list.</li>
+ *   <li>Space Complexity: O(n), due to the recursive call stack in the worst case.</li>
+ * </ul>
+ * </p>
+ */
 public class SearchSinglyLinkedListRecursion extends SinglyLinkedList {
 
-    public static void main(String[] args) {
-        SearchSinglyLinkedListRecursion list = new SearchSinglyLinkedListRecursion();
-        for (int i = 1; i <= 10; ++i) {
-            list.insert(i);
-        }
-
-        for (int i = 1; i <= 10; ++i) {
-            assert list.search(i);
-        }
-        assert !list.search(-1) && !list.search(100);
-    }
-
     /**
-     * Test if the value key is present in the list using recursion.
+     * Recursively searches for a given value in the linked list.
      *
-     * @param node the head node.
-     * @param key the value to be searched.
-     * @return {@code true} if key is present in the list, otherwise
-     * {@code false}.
+     * @param node the head node to start the search.
+     * @param key the integer value to be searched for.
+     * @return {@code true} if the value `key` is present in the list; otherwise, {@code false}.
      */
     private boolean searchRecursion(Node node, int key) {
         return (node != null && (node.value == key || searchRecursion(node.next, key)));
     }
 
+    /**
+     * Public search method to determine if a key is present in the linked list.
+     *
+     * @param key the integer value to be searched for.
+     * @return {@code true} if the value `key` is present in the list; otherwise, {@code false}.
+     */
     @Override
     public boolean search(int key) {
         return searchRecursion(getHead(), key);
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursionTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursionTest.java
new file mode 100644
index 000000000000..76b905841c18
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursionTest.java
@@ -0,0 +1,89 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class SearchSinglyLinkedListRecursionTest {
+
+    private SearchSinglyLinkedListRecursion list;
+
+    @BeforeEach
+    public void setUp() {
+        list = new SearchSinglyLinkedListRecursion();
+    }
+
+    @Test
+    public void testSearchInEmptyList() {
+        // Test searching for a value in an empty list (should return false)
+        assertFalse(list.search(1));
+    }
+
+    @Test
+    public void testSearchSingleElementListFound() {
+        // Insert a single element and search for it
+        list.insert(5);
+        assertTrue(list.search(5));
+    }
+
+    @Test
+    public void testSearchSingleElementListNotFound() {
+        // Insert a single element and search for a non-existent value
+        list.insert(5);
+        assertFalse(list.search(10));
+    }
+
+    @Test
+    public void testSearchMultipleElementsListFound() {
+        // Insert multiple elements and search for a middle value
+        for (int i = 1; i <= 10; i++) {
+            list.insert(i);
+        }
+        assertTrue(list.search(5));
+    }
+
+    @Test
+    public void testSearchMultipleElementsListFirstElement() {
+        // Insert multiple elements and search for the first element
+        for (int i = 1; i <= 10; i++) {
+            list.insert(i);
+        }
+        assertTrue(list.search(1));
+    }
+
+    @Test
+    public void testSearchMultipleElementsListLastElement() {
+        // Insert multiple elements and search for the last element
+        for (int i = 1; i <= 10; i++) {
+            list.insert(i);
+        }
+        assertTrue(list.search(10));
+    }
+
+    @Test
+    public void testSearchMultipleElementsListNotFound() {
+        // Insert multiple elements and search for a non-existent element
+        for (int i = 1; i <= 10; i++) {
+            list.insert(i);
+        }
+        assertFalse(list.search(15));
+    }
+
+    @Test
+    public void testSearchNegativeValues() {
+        // Insert positive and negative values and search for a negative value
+        list.insert(-5);
+        list.insert(-10);
+        list.insert(5);
+        assertTrue(list.search(-10));
+        assertFalse(list.search(-3));
+    }
+
+    @Test
+    public void testSearchZeroValue() {
+        list.insert(0);
+        assertTrue(list.search(0));
+    }
+}

From a1638165fead8abf2cab44f6ef58ba5592c4bead Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 26 Oct 2024 19:17:48 +0000
Subject: [PATCH 0697/1338] Bump
 org.apache.maven.plugins:maven-checkstyle-plugin from 3.5.0 to 3.6.0 (#6010)

---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index ec42ffc3c86d..d58039ee7a35 100644
--- a/pom.xml
+++ b/pom.xml
@@ -114,7 +114,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-checkstyle-plugin</artifactId>
-                <version>3.5.0</version>
+                <version>3.6.0</version>
                 <configuration>
                     <configLocation>checkstyle.xml</configLocation>
                     <consoleOutput>true</consoleOutput>

From a2e526b6101ad5662db38c4e802657695052b46d Mon Sep 17 00:00:00 2001
From: Giulio Tantaro <giulio.tantaro@gmail.com>
Date: Sun, 27 Oct 2024 21:39:56 +0100
Subject: [PATCH 0698/1338] Add tests for NodeStack (#6009)

---
 .../datastructures/stacks/NodeStack.java             | 11 -----------
 .../datastructures/stacks/NodeStackTest.java         | 12 ------------
 .../datastructures/trees/BinaryTreeTest.java         |  8 +++++++-
 3 files changed, 7 insertions(+), 24 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java b/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java
index 384cf3c0395a..bbcdfe1cc2a8 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java
@@ -95,15 +95,4 @@ public boolean isEmpty() {
     public int size() {
         return size;
     }
-
-    /**
-     * Prints the contents of the stack from top to bottom.
-     */
-    public void print() {
-        Node current = head;
-        while (current != null) {
-            System.out.println(current.data);
-            current = current.previous;
-        }
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java
index e05319359815..7ac0d8bc324b 100644
--- a/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java
@@ -70,16 +70,4 @@ void testSize() {
         stack.pop();
         assertEquals(0, stack.size(), "Size should be 0 after popping all elements.");
     }
-
-    @Test
-    void testPrint() {
-        NodeStack<Integer> stack = new NodeStack<>();
-        stack.push(1);
-        stack.push(2);
-        stack.push(3);
-
-        // Output verification would ideally be handled through a different means
-        // but you can print as a basic check to confirm method runs without errors.
-        stack.print();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java
index b153c5d667de..08a82e50ca02 100644
--- a/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.trees;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
 
 import org.junit.jupiter.api.Test;
 
@@ -35,7 +36,12 @@ void test2() {
         t.remove(5);
         t.remove(7);
 
-        assertEquals(t.getRoot().data, 9);
+        // Checks whether the root is null before accessing date
+        if (t.getRoot() != null) {
+            assertEquals(t.getRoot().data, 9);
+        } else {
+            fail("The root node is null after removal.");
+        }
     }
 
     // checks that removing an unexistend node returns false

From bca8d0efe0097423110276a3d540a2be97de5154 Mon Sep 17 00:00:00 2001
From: PANKAJ PATWAL <120747214+Chiefpatwal@users.noreply.github.com>
Date: Mon, 28 Oct 2024 02:24:30 +0530
Subject: [PATCH 0699/1338] Add Longest Subarray With Sum Less Than or Equal to
 K algorithm (#6042)

---
 .../datastructures/trees/BinaryTree.java      |   2 +-
 .../LongestSubarrayWithSumLessOrEqualToK.java |  48 ++++++++
 .../datastructures/trees/BinaryTreeTest.java  | 110 +++++++++---------
 ...gestSubarrayWithSumLessOrEqualToKTest.java |  22 ++++
 4 files changed, 124 insertions(+), 58 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToK.java
 create mode 100644 src/test/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToKTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java b/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java
index cf0de4a92030..ff02fe38970b 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java
@@ -144,7 +144,7 @@ public boolean remove(int value) {
             if (temp == root) {
                 root = null;
             } // This if/else assigns the new node to be either the left or right child of the
-              // parent
+            // parent
             else if (temp.parent.data < temp.data) {
                 temp.parent.right = null;
             } else {
diff --git a/src/main/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToK.java b/src/main/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToK.java
new file mode 100644
index 000000000000..55c3f709b467
--- /dev/null
+++ b/src/main/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToK.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.slidingwindow;
+
+/**
+ * The Longest Subarray with Sum Less Than or Equal to k algorithm finds the length
+ * of the longest subarray whose sum is less than or equal to a given value k.
+ *
+ * <p>
+ * Worst-case performance O(n)
+ * Best-case performance O(n)
+ * Average performance O(n)
+ * Worst-case space complexity O(1)
+ *
+ * @author https://github.com/Chiefpatwal
+ */
+public final class LongestSubarrayWithSumLessOrEqualToK {
+
+    // Prevent instantiation
+    private LongestSubarrayWithSumLessOrEqualToK() {
+    }
+
+    /**
+     * This method finds the length of the longest subarray with a sum less than or equal to k.
+     *
+     * @param arr is the input array
+     * @param k   is the maximum sum allowed
+     * @return the length of the longest subarray with sum less than or equal to k
+     */
+    public static int longestSubarrayWithSumLEK(int[] arr, int k) {
+        int maxLength = 0; // To store the maximum length found
+        int currentSum = 0; // To store the current sum of the window
+        int left = 0; // Left index of the sliding window
+
+        for (int right = 0; right < arr.length; right++) {
+            currentSum += arr[right]; // Expand the window to the right
+
+            // Shrink the window from the left if the current sum exceeds k
+            while (currentSum > k && left <= right) {
+                currentSum -= arr[left]; // Remove the leftmost element
+                left++; // Move the left index to the right
+            }
+
+            // Update maxLength if the current window is valid
+            maxLength = Math.max(maxLength, right - left + 1);
+        }
+
+        return maxLength; // Return the maximum length found
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java
index 08a82e50ca02..d6581fb8c4e8 100644
--- a/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java
@@ -1,82 +1,78 @@
 package com.thealgorithms.datastructures.trees;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.fail;
-
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
+/**
+ * Unit tests for the BinaryTree class.
+ */
 public class BinaryTreeTest {
 
-    // checks that adding populating the tree and searching for data
-    // retrieves the expected data
     @Test
-    void test1() {
-        BinaryTree t = new BinaryTree();
-        t.put(3);
-        t.put(5);
-        t.put(7);
-        t.put(9);
-        t.put(12);
+    public void testInsertAndFind() {
+        BinaryTree tree = new BinaryTree();
+        tree.put(3);
+        tree.put(5);
+        tree.put(7);
+        tree.put(9);
+        tree.put(12);
 
-        assertEquals(t.find(5).data, 5);
-        assertEquals(t.find(7).data, 7);
+        Assertions.assertNotNull(tree.find(5), "Node with value 5 should exist");
+        Assertions.assertEquals(5, tree.find(5).data, "Value of the found node should be 5");
+        Assertions.assertEquals(7, tree.find(7).data, "Value of the found node should be 7");
     }
 
-    // checks that removing data from the tree
-    // properly removes and makes the new root the expected new root
     @Test
-    void test2() {
-        BinaryTree t = new BinaryTree();
-        t.put(3);
-        t.put(5);
-        t.put(7);
-        t.put(9);
-        t.put(12);
-        t.remove(3);
-        t.remove(5);
-        t.remove(7);
+    public void testRemove() {
+        BinaryTree tree = new BinaryTree();
+        tree.put(3);
+        tree.put(5);
+        tree.put(7);
+        tree.put(9);
+        tree.put(12);
+        tree.remove(3);
+        tree.remove(5);
+        tree.remove(7);
 
-        // Checks whether the root is null before accessing date
-        if (t.getRoot() != null) {
-            assertEquals(t.getRoot().data, 9);
+        Assertions.assertNotNull(tree.getRoot(), "Root should not be null after removals");
+        if (tree.getRoot() != null) {
+            Assertions.assertEquals(9, tree.getRoot().data, "Root value should be 9 after removals");
         } else {
-            fail("The root node is null after removal.");
+            Assertions.fail("Root should not be null after removals, but it is.");
         }
     }
 
-    // checks that removing an unexistend node returns false
-    //  as specified by the documentation of the function
     @Test
-    void test3() {
-        BinaryTree t = new BinaryTree();
-        t.put(3);
-        t.put(5);
-        t.put(7);
-        t.put(9);
-        t.put(12);
+    public void testRemoveReturnValue() {
+        BinaryTree tree = new BinaryTree();
+        tree.put(3);
+        tree.put(5);
+        tree.put(7);
+        tree.put(9);
+        tree.put(12);
 
-        assertEquals(t.remove(9), true);
-        assertEquals(t.remove(398745987), false);
+        Assertions.assertTrue(tree.remove(9), "Removing existing node 9 should return true");
+        Assertions.assertFalse(tree.remove(398745987), "Removing non-existing node should return false");
     }
 
-    // check if the bfs, inOrder, preOrder and postOrder functions
-    // worg as expected, also increases the coverage measures in
-    // JaCoCo
     @Test
-    void test4() {
-        BinaryTree t = new BinaryTree();
-        t.put(3);
-        t.put(5);
-        t.put(7);
-        t.put(9);
-        t.put(12);
+    public void testTraversalMethods() {
+        BinaryTree tree = new BinaryTree();
+        tree.put(3);
+        tree.put(5);
+        tree.put(7);
+        tree.put(9);
+        tree.put(12);
+
+        // Testing traversal methods
+        tree.bfs(tree.getRoot());
+        tree.inOrder(tree.getRoot());
+        tree.preOrder(tree.getRoot());
+        tree.postOrder(tree.getRoot());
 
-        t.bfs(t.find(12));
-        t.inOrder(t.getRoot());
-        t.preOrder(t.getRoot());
-        t.postOrder(t.getRoot());
+        Assertions.assertTrue(tree.remove(9), "Removing existing node 9 should return true");
+        Assertions.assertFalse(tree.remove(398745987), "Removing non-existing node should return false");
 
-        assertEquals(t.remove(9), true);
-        assertEquals(t.remove(398745987), false);
+        Assertions.assertNotNull(tree.getRoot(), "Root should not be null after operations");
     }
 }
diff --git a/src/test/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToKTest.java b/src/test/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToKTest.java
new file mode 100644
index 000000000000..da282ab35ef3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToKTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.slidingwindow;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the LongestSubarrayWithSumLessOrEqualToK algorithm.
+ */
+public class LongestSubarrayWithSumLessOrEqualToKTest {
+
+    /**
+     * Tests for the longest subarray with a sum less than or equal to k.
+     */
+    @Test
+    public void testLongestSubarrayWithSumLEK() {
+        assertEquals(3, LongestSubarrayWithSumLessOrEqualToK.longestSubarrayWithSumLEK(new int[] {1, 2, 3, 4}, 6)); // {1, 2, 3}
+        assertEquals(4, LongestSubarrayWithSumLessOrEqualToK.longestSubarrayWithSumLEK(new int[] {1, 2, 3, 4}, 10)); // {1, 2, 3, 4}
+        assertEquals(2, LongestSubarrayWithSumLessOrEqualToK.longestSubarrayWithSumLEK(new int[] {5, 1, 2, 3}, 5)); // {5}
+        assertEquals(0, LongestSubarrayWithSumLessOrEqualToK.longestSubarrayWithSumLEK(new int[] {1, 2, 3}, 0)); // No valid subarray
+    }
+}

From 5c9edf4cbd8399f7e9a70e37cb430e2e16fdb989 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 29 Oct 2024 08:26:15 +0100
Subject: [PATCH 0700/1338] Bump com.puppycrawl.tools:checkstyle from 10.18.2
 to 10.19.0 (#6055)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.18.2 to 10.19.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.18.2...checkstyle-10.19.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index d58039ee7a35..a54290d85085 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.18.2</version>
+                    <version>10.19.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 5e9d1dcdcddde5dc3783e2b0fc5d9cab3c026839 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 29 Oct 2024 07:30:06 +0000
Subject: [PATCH 0701/1338] Bump org.apache.maven.plugins:maven-pmd-plugin from
 3.25.0 to 3.26.0 (#6054)

Bumps [org.apache.maven.plugins:maven-pmd-plugin](https://github.com/apache/maven-pmd-plugin) from 3.25.0 to 3.26.0.
- [Release notes](https://github.com/apache/maven-pmd-plugin/releases)
- [Commits](https://github.com/apache/maven-pmd-plugin/compare/maven-pmd-plugin-3.25.0...maven-pmd-plugin-3.26.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-pmd-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index a54290d85085..de43d4fb0daf 100644
--- a/pom.xml
+++ b/pom.xml
@@ -153,7 +153,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-pmd-plugin</artifactId>
-                <version>3.25.0</version>
+                <version>3.26.0</version>
                 <configuration>
                     <printFailingErrors>true</printFailingErrors>
                     <includeTests>true</includeTests>

From d1c1e6b4d251988e784bdab80e46ba4bfd531b02 Mon Sep 17 00:00:00 2001
From: Muhammad Junaid Khalid <mjk22071998@gmail.com>
Date: Tue, 29 Oct 2024 22:46:29 +0500
Subject: [PATCH 0702/1338] Add uniform number counting algorithm (#6052)

---
 DIRECTORY.md                                  |  4 ++
 .../thealgorithms/maths/UniformNumbers.java   | 50 +++++++++++++++++
 .../maths/UniformNumbersTest.java             | 56 +++++++++++++++++++
 3 files changed, 110 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/UniformNumbers.java
 create mode 100644 src/test/java/com/thealgorithms/maths/UniformNumbersTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0c9aeca4e59a..e34b9eba1247 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -466,6 +466,7 @@
             * [SumWithoutArithmeticOperators](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SumWithoutArithmeticOperators.java)
             * [TrinomialTriangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java)
             * [TwinPrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/TwinPrime.java)
+            * [UniformNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/UniformNumbers.java)
             * [VampireNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/VampireNumber.java)
             * [VectorCrossProduct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java)
             * [Volume](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Volume.java)
@@ -597,6 +598,7 @@
             * [UnionFind](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UnionFind.java)
             * [UpperBound](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UpperBound.java)
           * slidingwindow
+            * [LongestSubarrayWithSumLessOrEqualToK](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToK.java)
             * [LongestSubstringWithoutRepeatingCharacters](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java)
             * [MaxSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java)
             * [MinSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java)
@@ -1119,6 +1121,7 @@
             * [SumWithoutArithmeticOperatorsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SumWithoutArithmeticOperatorsTest.java)
             * [TestArmstrong](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TestArmstrong.java)
             * [TwinPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TwinPrimeTest.java)
+            * [UniformNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/UniformNumbersTest.java)
             * [VolumeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/VolumeTest.java)
           * misc
             * [ColorContrastRatioTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java)
@@ -1228,6 +1231,7 @@
             * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java)
             * [UpperBoundTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UpperBoundTest.java)
           * slidingwindow
+            * [LongestSubarrayWithSumLessOrEqualToKTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToKTest.java)
             * [LongestSubstringWithoutRepeatingCharactersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java)
             * [MaxSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java)
             * [MinSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java)
diff --git a/src/main/java/com/thealgorithms/maths/UniformNumbers.java b/src/main/java/com/thealgorithms/maths/UniformNumbers.java
new file mode 100644
index 000000000000..c83783aab0b3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/UniformNumbers.java
@@ -0,0 +1,50 @@
+package com.thealgorithms.maths;
+
+/**
+ * A positive integer is considered uniform if all
+ * of its digits are equal. For example, 222 is uniform,
+ * while 223 is not.
+ * Given two positive integers a and b, determine the
+ * number of uniform integers between a and b.
+ */
+public final class UniformNumbers {
+    // Private constructor to prevent instantiation of the utility class
+    private UniformNumbers() {
+        // Prevent instantiation
+    }
+    /**
+     * This function will find the number of uniform numbers
+     * from 1 to num
+     * @param num upper limit to find the uniform numbers
+     * @return the count of uniform numbers between 1 and num
+     */
+    public static int uniformNumbers(int num) {
+        String numStr = Integer.toString(num);
+        int uniformCount = (numStr.length() - 1) * 9;
+        int finalUniform = Integer.parseInt(String.valueOf(numStr.charAt(0)).repeat(numStr.length()));
+
+        if (finalUniform <= num) {
+            uniformCount += Integer.parseInt(String.valueOf(numStr.charAt(0)));
+        } else {
+            uniformCount += Integer.parseInt(String.valueOf(numStr.charAt(0))) - 1;
+        }
+
+        return uniformCount;
+    }
+    /**
+     * This function will calculate the number of uniform numbers
+     * between a and b
+     * @param a lower bound of range
+     * @param b upper bound of range
+     * @return  the count of uniform numbers between a and b
+     */
+    public static int countUniformIntegers(int a, int b) {
+        if (b > a && b > 0 && a > 0) {
+            return uniformNumbers(b) - uniformNumbers(a - 1);
+        } else if (b == a) {
+            return 1;
+        } else {
+            return 0;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/UniformNumbersTest.java b/src/test/java/com/thealgorithms/maths/UniformNumbersTest.java
new file mode 100644
index 000000000000..ac46c00014ad
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/UniformNumbersTest.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class UniformNumbersTest {
+
+    @Test
+    void testSingleUniformDigitRange() {
+        assertEquals(1, UniformNumbers.countUniformIntegers(1, 1));
+        assertEquals(9, UniformNumbers.countUniformIntegers(1, 9));
+    }
+
+    @Test
+    void testSmallRange() {
+        assertEquals(1, UniformNumbers.countUniformIntegers(10, 11));
+        assertEquals(2, UniformNumbers.countUniformIntegers(22, 33));
+    }
+
+    @Test
+    void testRangeWithNoUniformNumbers() {
+        assertEquals(0, UniformNumbers.countUniformIntegers(12, 21));
+        assertEquals(0, UniformNumbers.countUniformIntegers(123, 128));
+    }
+
+    @Test
+    void testRangeWithAllUniformNumbers() {
+        assertEquals(9, UniformNumbers.countUniformIntegers(1, 9));
+        assertEquals(18, UniformNumbers.countUniformIntegers(1, 99));
+    }
+
+    @Test
+    void testMultiDigitRangeWithUniformNumbers() {
+        assertEquals(1, UniformNumbers.countUniformIntegers(100, 111));
+        assertEquals(2, UniformNumbers.countUniformIntegers(111, 222));
+    }
+
+    @Test
+    void testExactUniformBoundary() {
+        assertEquals(1, UniformNumbers.countUniformIntegers(111, 111));
+        assertEquals(2, UniformNumbers.countUniformIntegers(111, 222));
+    }
+
+    @Test
+    void testLargeRange() {
+        assertEquals(27, UniformNumbers.countUniformIntegers(1, 999));
+        assertEquals(36, UniformNumbers.countUniformIntegers(1, 9999));
+    }
+
+    @Test
+    void testInvalidRange() {
+        assertEquals(0, UniformNumbers.countUniformIntegers(500, 100));
+        assertEquals(0, UniformNumbers.countUniformIntegers(-100, -1));
+    }
+}

From e94be712df05af1816d833f6f645b485bea06806 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 29 Oct 2024 23:22:37 +0530
Subject: [PATCH 0703/1338] Add `RandomScheduling` algorithm (#5810)

---
 DIRECTORY.md                                  |  2 +
 .../scheduling/RandomScheduling.java          | 45 +++++++++
 .../scheduling/RandomSchedulingTest.java      | 93 +++++++++++++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/scheduling/RandomScheduling.java
 create mode 100644 src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index e34b9eba1247..1fc9ec0ce9cf 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -560,6 +560,7 @@
             * [NonPreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [ProportionalFairScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java)
+            * [RandomScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RandomScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
             * [SelfAdjustingScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java)
             * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
@@ -1192,6 +1193,7 @@
             * [NonPreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [ProportionalFairSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java)
+            * [RandomSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
             * [SelfAdjustingSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java)
             * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)
diff --git a/src/main/java/com/thealgorithms/scheduling/RandomScheduling.java b/src/main/java/com/thealgorithms/scheduling/RandomScheduling.java
new file mode 100644
index 000000000000..b7e863b5cfd8
--- /dev/null
+++ b/src/main/java/com/thealgorithms/scheduling/RandomScheduling.java
@@ -0,0 +1,45 @@
+package com.thealgorithms.scheduling;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Random;
+
+/**
+ * RandomScheduling is an algorithm that assigns tasks in a random order.
+ * It doesn't consider priority, deadlines, or burst times, making it
+ * inefficient but useful in scenarios where fairness or unpredictability
+ * is required (e.g., load balancing in distributed systems).
+ *
+ * Use Case: Distributed systems where randomness helps avoid task starvation.
+ *
+ * @author Hardvan
+ */
+public final class RandomScheduling {
+
+    private final List<String> tasks;
+    private final Random random;
+
+    /**
+     * Constructs a new RandomScheduling instance.
+     *
+     * @param tasks A collection of task names to be scheduled.
+     * @param random A Random instance for generating random numbers.
+     */
+    public RandomScheduling(Collection<String> tasks, Random random) {
+        this.tasks = new ArrayList<>(tasks);
+        this.random = random;
+    }
+
+    /**
+     * Schedules the tasks randomly and returns the randomized order.
+     *
+     * @return A list representing the tasks in their randomized execution order.
+     */
+    public List<String> schedule() {
+        List<String> shuffledTasks = new ArrayList<>(tasks);
+        Collections.shuffle(shuffledTasks, random);
+        return shuffledTasks;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java
new file mode 100644
index 000000000000..e2c8777d892f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java
@@ -0,0 +1,93 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.anyInt;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.util.List;
+import java.util.Random;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class RandomSchedulingTest {
+
+    private RandomScheduling randomScheduling;
+    private Random mockRandom;
+
+    @BeforeEach
+    public void setup() {
+        mockRandom = mock(Random.class); // Mocking Random for predictable behavior
+    }
+
+    @Test
+    public void testRandomOrder1() {
+        // Arrange
+        List<String> tasks = List.of("Task1", "Task2", "Task3");
+        // Mock the random sequence to control shuffling: swap 0 <-> 1, and 1 <-> 2.
+        when(mockRandom.nextInt(anyInt())).thenReturn(1, 2, 0);
+        randomScheduling = new RandomScheduling(tasks, mockRandom);
+
+        // Act
+        List<String> result = randomScheduling.schedule();
+
+        // Assert
+        assertEquals(List.of("Task1", "Task2", "Task3"), result);
+    }
+
+    @Test
+    public void testRandomOrder2() {
+        // Arrange
+        List<String> tasks = List.of("A", "B", "C", "D");
+        // Mocking predictable swaps for the sequence: [C, B, D, A]
+        when(mockRandom.nextInt(anyInt())).thenReturn(2, 1, 3, 0);
+        randomScheduling = new RandomScheduling(tasks, mockRandom);
+
+        // Act
+        List<String> result = randomScheduling.schedule();
+
+        // Assert
+        assertEquals(List.of("A", "C", "B", "D"), result);
+    }
+
+    @Test
+    public void testSingleTask() {
+        // Arrange
+        List<String> tasks = List.of("SingleTask");
+        when(mockRandom.nextInt(anyInt())).thenReturn(0); // No real shuffle
+        randomScheduling = new RandomScheduling(tasks, mockRandom);
+
+        // Act
+        List<String> result = randomScheduling.schedule();
+
+        // Assert
+        assertEquals(List.of("SingleTask"), result);
+    }
+
+    @Test
+    public void testEmptyTaskList() {
+        // Arrange
+        List<String> tasks = List.of();
+        randomScheduling = new RandomScheduling(tasks, mockRandom);
+
+        // Act
+        List<String> result = randomScheduling.schedule();
+
+        // Assert
+        assertEquals(List.of(), result); // Should return an empty list
+    }
+
+    @Test
+    public void testSameTasksMultipleTimes() {
+        // Arrange
+        List<String> tasks = List.of("X", "X", "Y", "Z");
+        when(mockRandom.nextInt(anyInt())).thenReturn(3, 0, 1, 2);
+        randomScheduling = new RandomScheduling(tasks, mockRandom);
+
+        // Act
+        List<String> result = randomScheduling.schedule();
+
+        // Assert
+        assertEquals(List.of("Y", "X", "X", "Z"), result);
+    }
+}

From b31bc86192972409632e75552145d3445928b22c Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 29 Oct 2024 23:32:33 +0530
Subject: [PATCH 0704/1338] Enhance docs, add tests in AVLTree (#6058)

---
 DIRECTORY.md                                  |   1 +
 .../datastructures/trees/AVLTree.java         | 144 ++++++++++--------
 .../datastructures/trees/AVLTreeTest.java     | 101 ++++++++++++
 3 files changed, 184 insertions(+), 62 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/AVLTreeTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 1fc9ec0ce9cf..0f7184cdb7e5 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -912,6 +912,7 @@
               * [StackArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java)
               * [StackOfLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java)
             * trees
+              * [AVLTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/AVLTreeTest.java)
               * [BinaryTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java)
               * [BoundaryTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BoundaryTraversalTest.java)
               * [BSTFromSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTFromSortedArrayTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java b/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java
index 7b959b085353..77ee5d5fa23e 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java
@@ -1,11 +1,19 @@
 package com.thealgorithms.datastructures.trees;
 
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Represents an AVL Tree, a self-balancing binary search tree.
+ * In an AVL tree, the heights of the two child subtrees of any node
+ * differ by at most one. If they differ by more than one at any time,
+ * rebalancing is performed to restore this property.
+ */
 public class AVLTree {
 
     private Node root;
 
-    private class Node {
-
+    private static class Node {
         private int key;
         private int balance;
         private int height;
@@ -17,8 +25,18 @@ private class Node {
             key = k;
             parent = p;
         }
+
+        public Integer getBalance() {
+            return balance;
+        }
     }
 
+    /**
+     * Inserts a new key into the AVL tree.
+     *
+     * @param key the key to be inserted
+     * @return {@code true} if the key was inserted, {@code false} if the key already exists
+     */
     public boolean insert(int key) {
         if (root == null) {
             root = new Node(key, null);
@@ -31,7 +49,6 @@ public boolean insert(int key) {
                 }
 
                 parent = n;
-
                 boolean goLeft = n.key > key;
                 n = goLeft ? n.left : n.right;
 
@@ -49,8 +66,32 @@ public boolean insert(int key) {
         return true;
     }
 
+    /**
+     * Deletes a key from the AVL tree.
+     *
+     * @param delKey the key to be deleted
+     */
+    public void delete(int delKey) {
+        if (root == null) {
+            return;
+        }
+
+        // Find the node to be deleted
+        Node node = root;
+        Node child = root;
+        while (child != null) {
+            node = child;
+            child = delKey >= node.key ? node.right : node.left;
+            if (delKey == node.key) {
+                delete(node);
+                return;
+            }
+        }
+    }
+
     private void delete(Node node) {
         if (node.left == null && node.right == null) {
+            // Leaf node
             if (node.parent == null) {
                 root = null;
             } else {
@@ -64,6 +105,8 @@ private void delete(Node node) {
             }
             return;
         }
+
+        // Node has one or two children
         Node child;
         if (node.left != null) {
             child = node.left;
@@ -80,26 +123,49 @@ private void delete(Node node) {
         delete(child);
     }
 
-    public void delete(int delKey) {
-        if (root == null) {
-            return;
+    /**
+     * Returns a list of balance factors for each node in the tree.
+     *
+     * @return a list of integers representing the balance factors of the nodes
+     */
+    public List<Integer> returnBalance() {
+        List<Integer> balances = new ArrayList<>();
+        returnBalance(root, balances);
+        return balances;
+    }
+
+    private void returnBalance(Node n, List<Integer> balances) {
+        if (n != null) {
+            returnBalance(n.left, balances);
+            balances.add(n.getBalance());
+            returnBalance(n.right, balances);
         }
-        Node node = root;
-        Node child = root;
+    }
 
-        while (child != null) {
-            node = child;
-            child = delKey >= node.key ? node.right : node.left;
-            if (delKey == node.key) {
-                delete(node);
-                return;
-            }
+    /**
+     * Searches for a key in the AVL tree.
+     *
+     * @param key the key to be searched
+     * @return true if the key is found, false otherwise
+     */
+    public boolean search(int key) {
+        Node result = searchHelper(this.root, key);
+        return result != null;
+    }
+
+    private Node searchHelper(Node root, int key) {
+        if (root == null || root.key == key) {
+            return root;
         }
+
+        if (root.key > key) {
+            return searchHelper(root.left, key);
+        }
+        return searchHelper(root.right, key);
     }
 
     private void rebalance(Node n) {
         setBalance(n);
-
         if (n.balance == -2) {
             if (height(n.left.left) >= height(n.left.right)) {
                 n = rotateRight(n);
@@ -143,7 +209,6 @@ private Node rotateLeft(Node a) {
         }
 
         setBalance(a, b);
-
         return b;
     }
 
@@ -169,7 +234,6 @@ private Node rotateRight(Node a) {
         }
 
         setBalance(a, b);
-
         return b;
     }
 
@@ -197,53 +261,9 @@ private void setBalance(Node... nodes) {
         }
     }
 
-    public void printBalance() {
-        printBalance(root);
-    }
-
-    private void printBalance(Node n) {
-        if (n != null) {
-            printBalance(n.left);
-            System.out.printf("%s ", n.balance);
-            printBalance(n.right);
-        }
-    }
-
     private void reheight(Node node) {
         if (node != null) {
             node.height = 1 + Math.max(height(node.left), height(node.right));
         }
     }
-
-    public boolean search(int key) {
-        Node result = searchHelper(this.root, key);
-        return result != null;
-    }
-
-    private Node searchHelper(Node root, int key) {
-        // root is null or key is present at root
-        if (root == null || root.key == key) {
-            return root;
-        }
-
-        // key is greater than root's key
-        if (root.key > key) {
-            return searchHelper(root.left, key); // call the function on the node's left child
-        }
-        // key is less than root's key then
-        // call the function on the node's right child as it is greater
-        return searchHelper(root.right, key);
-    }
-
-    public static void main(String[] args) {
-        AVLTree tree = new AVLTree();
-
-        System.out.println("Inserting values 1 to 10");
-        for (int i = 1; i < 10; i++) {
-            tree.insert(i);
-        }
-
-        System.out.print("Printing balance: ");
-        tree.printBalance();
-    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/AVLTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/AVLTreeTest.java
new file mode 100644
index 000000000000..6aa5dc9e22ed
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/AVLTreeTest.java
@@ -0,0 +1,101 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class AVLTreeTest {
+    private AVLTree avlTree;
+
+    @BeforeEach
+    public void setUp() {
+        avlTree = new AVLTree();
+    }
+
+    @Test
+    public void testInsert() {
+        assertTrue(avlTree.insert(10));
+        assertTrue(avlTree.insert(20));
+        assertTrue(avlTree.insert(5));
+        assertFalse(avlTree.insert(10)); // Duplicate
+    }
+
+    @Test
+    public void testSearch() {
+        avlTree.insert(15);
+        avlTree.insert(25);
+        assertTrue(avlTree.search(15));
+        assertFalse(avlTree.search(30)); // Not in the tree
+    }
+
+    @Test
+    public void testDeleteLeafNode() {
+        avlTree.insert(10);
+        avlTree.insert(20);
+        avlTree.insert(30);
+        avlTree.delete(30);
+        assertFalse(avlTree.search(30));
+    }
+
+    @Test
+    public void testDeleteNodeWithOneChild() {
+        avlTree.insert(20);
+        avlTree.insert(10);
+        avlTree.insert(30);
+        avlTree.delete(10);
+        assertFalse(avlTree.search(10));
+    }
+
+    @Test
+    public void testDeleteNodeWithTwoChildren() {
+        avlTree.insert(20);
+        avlTree.insert(10);
+        avlTree.insert(30);
+        avlTree.insert(25);
+        avlTree.delete(20);
+        assertFalse(avlTree.search(20));
+        assertTrue(avlTree.search(30));
+        assertTrue(avlTree.search(25));
+    }
+
+    @Test
+    public void testReturnBalance() {
+        avlTree.insert(10);
+        avlTree.insert(20);
+        avlTree.insert(5);
+        List<Integer> balances = avlTree.returnBalance();
+        assertEquals(3, balances.size()); // There should be 3 nodes
+        assertEquals(0, balances.get(0)); // Balance for node 5
+        assertEquals(0, balances.get(1)); // Balance for node 10
+        assertEquals(0, balances.get(2)); // Balance for node 20
+    }
+
+    @Test
+    public void testInsertAndRebalance() {
+        avlTree.insert(30);
+        avlTree.insert(20);
+        avlTree.insert(10); // This should cause a right rotation
+        assertTrue(avlTree.search(20));
+        assertTrue(avlTree.search(10));
+        assertTrue(avlTree.search(30));
+    }
+
+    @Test
+    public void testComplexInsertionAndDeletion() {
+        avlTree.insert(30);
+        avlTree.insert(20);
+        avlTree.insert(10);
+        avlTree.insert(25);
+        avlTree.insert(5);
+        avlTree.insert(15);
+
+        avlTree.delete(20); // Test deletion
+        assertFalse(avlTree.search(20));
+        assertTrue(avlTree.search(30));
+        assertTrue(avlTree.search(25));
+    }
+}

From 54567e2ed3d0e7181b7b454fc028d6a72f6e8183 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 29 Oct 2024 23:42:46 +0530
Subject: [PATCH 0705/1338] Enhance docs, add more tests in `SwapAdjacentBits`
 (#5861)

---
 .../bitmanipulation/SwapAdjacentBits.java     | 37 +++++++++++++++++--
 .../bitmanipulation/SwapAdjacentBitsTest.java | 21 +++++++----
 2 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java b/src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java
index 933dec5654a0..98a7de8bdf1a 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java
@@ -1,14 +1,45 @@
 package com.thealgorithms.bitmanipulation;
 
 /**
- * Swap every pair of adjacent bits of a given number.
- * @author Lakshyajeet Singh Goyal (https://github.com/DarkMatter-999)
+ * A utility class to swap every pair of adjacent bits in a given integer.
+ * This operation shifts the even-positioned bits to odd positions and vice versa.
+ *
+ * Example:
+ * - Input: 2 (binary: `10`) → Output: 1 (binary: `01`)
+ * - Input: 43 (binary: `101011`) → Output: 23 (binary: `010111`)
+ *
+ * **Explanation of the Algorithm:**
+ * 1. Mask even-positioned bits: Using `0xAAAAAAAA` (binary: `101010...`),
+ *    which selects bits in even positions.
+ * 2. Mask odd-positioned bits: Using `0x55555555` (binary: `010101...`),
+ *    which selects bits in odd positions.
+ * 3. Shift bits:
+ *    - Right-shift even-positioned bits by 1 to move them to odd positions.
+ *    - Left-shift odd-positioned bits by 1 to move them to even positions.
+ * 4. Combine both shifted results using bitwise OR (`|`) to produce the final result.
+ *
+ * Use Case: This algorithm can be useful in applications involving low-level bit manipulation,
+ * such as encoding, data compression, or cryptographic transformations.
+ *
+ * Time Complexity: O(1) (constant time, since operations are bitwise).
+ *
+ * Author: Lakshyajeet Singh Goyal (https://github.com/DarkMatter-999)
  */
-
 public final class SwapAdjacentBits {
     private SwapAdjacentBits() {
     }
 
+    /**
+     * Swaps every pair of adjacent bits of a given integer.
+     * Steps:
+     * 1. Mask the even-positioned bits.
+     * 2. Mask the odd-positioned bits.
+     * 3. Shift the even bits to the right and the odd bits to the left.
+     * 4. Combine the shifted bits.
+     *
+     * @param num the integer whose bits are to be swapped
+     * @return the integer after swapping every pair of adjacent bits
+     */
     public static int swapAdjacentBits(int num) {
         // mask the even bits (0xAAAAAAAA => 10101010...)
         int evenBits = num & 0xAAAAAAAA;
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java
index 67c986136ab0..12f0542b92f6 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java
@@ -8,13 +8,20 @@
 class SwapAdjacentBitsTest {
 
     @ParameterizedTest
-    @CsvSource({
-        "2, 1", // 2 (10 in binary) should become 1 (01 in binary)
-        "43, 23", // 43 should become 23
-        "153, 102", // 153 should become 102
-        "15, 15", // 15 (1111) remains 15 (1111)
-        "0, 0" // 0 (0000) remains 0 (0000)
-    })
+    @CsvSource({"2, 1", // 2 (binary: 10) -> 1 (binary: 01)
+        "43, 23", // 43 (binary: 101011) -> 23 (binary: 010111)
+        "153, 102", // 153 (binary: 10011001) -> 102 (binary: 01100110)
+        "15, 15", // 15 (binary: 1111) -> 15 (binary: 1111) (no change)
+        "0, 0", // 0 (binary: 0000) -> 0 (binary: 0000) (no change)
+        "1, 2", // 1 (binary: 01) -> 2 (binary: 10)
+        "170, 85", // 170 (binary: 10101010) -> 85 (binary: 01010101)
+        "85, 170", // 85 (binary: 01010101) -> 170 (binary: 10101010)
+        "255, 255", // 255 (binary: 11111111) -> 255 (binary: 11111111) (no change)
+        "128, 64", // 128 (binary: 10000000) -> 64 (binary: 01000000)
+        "1024, 2048",
+        "-1, -1", // -1 (all bits 1) remains -1 (no change due to two's complement)
+        "-2, -3", // -2 (binary: ...1110) -> -3 (binary: ...1101)
+        "2147483647, -1073741825", "-2147483648, -1073741824"})
     void
     testSwapAdjacentBits(int input, int expected) {
         assertEquals(expected, SwapAdjacentBits.swapAdjacentBits(input));

From fd14016c8659c8b2b8220325a77178876f8c5c1d Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Tue, 29 Oct 2024 23:47:30 +0530
Subject: [PATCH 0706/1338] Enhance docs, add more tests in `ReverseBits`
 (#5859)

---
 .../bitmanipulation/ReverseBits.java          | 23 ++++++++++-
 .../bitmanipulation/ReverseBitsTest.java      | 38 ++++++++++++++++---
 2 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java b/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java
index e8f2930d3afe..12c269d9be48 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java
@@ -1,14 +1,33 @@
 package com.thealgorithms.bitmanipulation;
 
 /**
- * Converts any Octal Number to a Binary Number
+ * This class provides a method to reverse the bits of a 32-bit integer.
+ * Reversing the bits means that the least significant bit (LSB) becomes
+ * the most significant bit (MSB) and vice versa.
+ *
+ * Example:
+ * Input (binary): 00000010100101000001111010011100 (43261596)
+ * Output (binary): 00111001011110000010100101000000 (964176192)
+ *
+ * Time Complexity: O(32) - A fixed number of 32 iterations
+ * Space Complexity: O(1) - No extra space used
+ *
+ * Note:
+ * - If the input is negative, Java handles it using two’s complement representation.
+ * - This function works on 32-bit integers by default.
+ *
  * @author Bama Charan Chhandogi
  */
-
 public final class ReverseBits {
     private ReverseBits() {
     }
 
+    /**
+     * Reverses the bits of a 32-bit integer.
+     *
+     * @param n the integer whose bits are to be reversed
+     * @return the integer obtained by reversing the bits of the input
+     */
     public static int reverseBits(int n) {
         int result = 0;
         int bitCount = 32;
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java
index 967a89a1ee97..5cfa82355ce7 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java
@@ -2,14 +2,40 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class ReverseBitsTest {
 
-    @Test
-    void testReverseBits() {
-        assertEquals(0, ReverseBits.reverseBits(0));
-        assertEquals(-1, ReverseBits.reverseBits(-1));
-        assertEquals(964176192, ReverseBits.reverseBits(43261596));
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testReverseBits(int input, int expected) {
+        assertEquals(expected, ReverseBits.reverseBits(input));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            // Edge case: All bits are 0
+            Arguments.of(0, 0),
+
+            // Edge case: All bits are 1 (Two’s complement representation of -1)
+            Arguments.of(-1, -1),
+
+            // Case with random number 43261596
+            Arguments.of(43261596, 964176192),
+
+            // Case with maximum positive value for 32-bit integer
+            Arguments.of(Integer.MAX_VALUE, -2),
+
+            // Case with minimum value (all bits 1 except the sign bit)
+            Arguments.of(Integer.MIN_VALUE, 1),
+
+            // Case with a single bit set (2^0 = 1)
+            Arguments.of(1, Integer.MIN_VALUE),
+
+            // Case with alternating bits: 0b101010...10 (in binary)
+            Arguments.of(0xAAAAAAAA, 0x55555555));
     }
 }

From 63d13b6f3abd800e2eaac6bc7b39535f58e6672e Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 30 Oct 2024 00:21:27 +0530
Subject: [PATCH 0707/1338] Enhance docs, add tests in
 `GenericHashMapUsingArray` (#5972)

---
 .../hashing/GenericHashMapUsingArray.java     | 118 ++++++++++++++----
 .../hashing/GenericHashMapUsingArrayTest.java |  43 +++++++
 2 files changed, 140 insertions(+), 21 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
index 416cee99d028..3637e323f097 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
@@ -2,23 +2,45 @@
 
 import java.util.LinkedList;
 
-// implementation of generic hashmaps using array of Linked Lists
-
+/**
+ * A generic implementation of a hash map using an array of linked lists for collision resolution.
+ * This class provides a way to store key-value pairs efficiently, allowing for average-case
+ * constant time complexity for insertion, deletion, and retrieval operations.
+ *
+ * <p>
+ * The hash map uses separate chaining for collision resolution. Each bucket in the hash map is a
+ * linked list that stores nodes containing key-value pairs. When a collision occurs (i.e., when
+ * two keys hash to the same index), the new key-value pair is simply added to the corresponding
+ * linked list.
+ * </p>
+ *
+ * <p>
+ * The hash map automatically resizes itself when the load factor exceeds 0.75. The load factor is
+ * defined as the ratio of the number of entries to the number of buckets. When resizing occurs,
+ * all existing entries are rehashed and inserted into the new buckets.
+ * </p>
+ *
+ * @param <K> the type of keys maintained by this hash map
+ * @param <V> the type of mapped values
+ */
 public class GenericHashMapUsingArray<K, V> {
 
-    private int size; // n (total number of key-value pairs)
-    private LinkedList<Node>[] buckets; // N = buckets.length
-    private float lf = 0.75f;
+    private int size; // Total number of key-value pairs
+    private LinkedList<Node>[] buckets; // Array of linked lists (buckets) for storing entries
 
+    /**
+     * Constructs a new empty hash map with an initial capacity of 16.
+     */
     public GenericHashMapUsingArray() {
         initBuckets(16);
         size = 0;
     }
 
-    // load factor = 0.75 means if we need to add 100 items and we have added
-    // 75, then adding 76th item it will double the size, copy all elements
-    // & then add 76th item.
-
+    /**
+     * Initializes the buckets for the hash map with the specified number of buckets.
+     *
+     * @param n the number of buckets to initialize
+     */
     private void initBuckets(int n) {
         buckets = new LinkedList[n];
         for (int i = 0; i < buckets.length; i++) {
@@ -26,43 +48,66 @@ private void initBuckets(int n) {
         }
     }
 
+    /**
+     * Associates the specified value with the specified key in this map.
+     * If the map previously contained a mapping for the key, the old value is replaced.
+     *
+     * @param key the key with which the specified value is to be associated
+     * @param value the value to be associated with the specified key
+     */
     public void put(K key, V value) {
         int bucketIndex = hashFunction(key);
         LinkedList<Node> nodes = buckets[bucketIndex];
-        for (Node node : nodes) { // if key present => update
+        // Update existing key's value if present
+        for (Node node : nodes) {
             if (node.key.equals(key)) {
                 node.value = value;
                 return;
             }
         }
 
-        // key is not present => insert
+        // Insert new key-value pair
         nodes.add(new Node(key, value));
         size++;
 
-        if ((float) size / buckets.length > lf) {
+        // Check if rehashing is needed
+        // Load factor threshold for resizing
+        float loadFactorThreshold = 0.75f;
+        if ((float) size / buckets.length > loadFactorThreshold) {
             reHash();
         }
     }
 
-    // tells which bucket to go to
+    /**
+     * Returns the index of the bucket in which the key would be stored.
+     *
+     * @param key the key whose bucket index is to be computed
+     * @return the bucket index
+     */
     private int hashFunction(K key) {
         return Math.floorMod(key.hashCode(), buckets.length);
     }
 
+    /**
+     * Rehashes the map by doubling the number of buckets and re-inserting all entries.
+     */
     private void reHash() {
-        System.out.println("Rehashing!");
-        LinkedList<Node>[] old = buckets;
-        initBuckets(old.length * 2);
+        LinkedList<Node>[] oldBuckets = buckets;
+        initBuckets(oldBuckets.length * 2);
         this.size = 0;
 
-        for (LinkedList<Node> nodes : old) {
+        for (LinkedList<Node> nodes : oldBuckets) {
             for (Node node : nodes) {
                 put(node.key, node.value);
             }
         }
     }
 
+    /**
+     * Removes the mapping for the specified key from this map if present.
+     *
+     * @param key the key whose mapping is to be removed from the map
+     */
     public void remove(K key) {
         int bucketIndex = hashFunction(key);
         LinkedList<Node> nodes = buckets[bucketIndex];
@@ -74,14 +119,28 @@ public void remove(K key) {
                 break;
             }
         }
-        nodes.remove(target);
-        size--;
+
+        if (target != null) {
+            nodes.remove(target);
+            size--;
+        }
     }
 
+    /**
+     * Returns the number of key-value pairs in this map.
+     *
+     * @return the number of key-value pairs
+     */
     public int size() {
         return this.size;
     }
 
+    /**
+     * Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.
+     *
+     * @param key the key whose associated value is to be returned
+     * @return the value associated with the specified key, or null if no mapping exists
+     */
     public V get(K key) {
         int bucketIndex = hashFunction(key);
         LinkedList<Node> nodes = buckets[bucketIndex];
@@ -96,7 +155,6 @@ public V get(K key) {
     @Override
     public String toString() {
         StringBuilder builder = new StringBuilder();
-
         builder.append("{");
         for (LinkedList<Node> nodes : buckets) {
             for (Node node : nodes) {
@@ -106,19 +164,37 @@ public String toString() {
                 builder.append(", ");
             }
         }
+        // Remove trailing comma and space
+        if (builder.length() > 1) {
+            builder.setLength(builder.length() - 2);
+        }
         builder.append("}");
         return builder.toString();
     }
 
+    /**
+     * Returns true if this map contains a mapping for the specified key.
+     *
+     * @param key the key whose presence in this map is to be tested
+     * @return true if this map contains a mapping for the specified key
+     */
     public boolean containsKey(K key) {
         return get(key) != null;
     }
 
+    /**
+     * A private class representing a key-value pair (node) in the hash map.
+     */
     public class Node {
-
         K key;
         V value;
 
+        /**
+         * Constructs a new Node with the specified key and value.
+         *
+         * @param key the key of the key-value pair
+         * @param value the value of the key-value pair
+         */
         public Node(K key, V value) {
             this.key = key;
             this.value = value;
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java
index 483e43bb5cb3..5d1733a3e97c 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java
@@ -50,4 +50,47 @@ void testGenericHashmapWhichUsesArrayAndKeyIsIntegerValueIsString() {
         assertEquals("Washington DC", map.get(101));
         assertTrue(map.containsKey(46));
     }
+
+    @Test
+    void testRemoveNonExistentKey() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        map.put("USA", "Washington DC");
+        map.remove("Nepal"); // Attempting to remove a non-existent key
+        assertEquals(1, map.size()); // Size should remain the same
+    }
+
+    @Test
+    void testRehashing() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        for (int i = 0; i < 20; i++) {
+            map.put("Key" + i, "Value" + i);
+        }
+        assertEquals(20, map.size()); // Ensure all items were added
+        assertEquals("Value5", map.get("Key5")); // Check retrieval after rehash
+    }
+
+    @Test
+    void testUpdateValueForExistingKey() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        map.put("USA", "Washington DC");
+        map.put("USA", "New Washington DC"); // Updating value for existing key
+        assertEquals("New Washington DC", map.get("USA"));
+    }
+
+    @Test
+    void testToStringMethod() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        map.put("USA", "Washington DC");
+        map.put("Nepal", "Kathmandu");
+        String expected = "{USA : Washington DC, Nepal : Kathmandu}";
+        assertEquals(expected, map.toString());
+    }
+
+    @Test
+    void testContainsKey() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        map.put("USA", "Washington DC");
+        assertTrue(map.containsKey("USA"));
+        assertFalse(map.containsKey("Nepal"));
+    }
 }

From 94fb92e508a4860f76ec2897b27c00f603ed75e2 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 30 Oct 2024 01:41:30 +0530
Subject: [PATCH 0708/1338] Enhance docs, add tests in `GenericHeap` (#5980)

---
 .../datastructures/heaps/GenericHeap.java     |  85 +++++++++++--
 .../datastructures/heaps/GenericHeapTest.java | 119 ++++++------------
 2 files changed, 112 insertions(+), 92 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java
index f1772b5b3112..b8a289db60b9 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java
@@ -3,49 +3,83 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 
+/**
+ * A generic implementation of a max heap data structure.
+ *
+ * @param <T> the type of elements in this heap, must extend Comparable.
+ */
 public class GenericHeap<T extends Comparable<T>> {
 
-    ArrayList<T> data = new ArrayList<>();
-    HashMap<T, Integer> map = new HashMap<>();
+    private final ArrayList<T> data = new ArrayList<>();
+    private final HashMap<T, Integer> map = new HashMap<>();
 
+    /**
+     * Adds an item to the heap, maintaining the heap property.
+     *
+     * @param item the item to be added
+     */
     public void add(T item) {
         if (item == null) {
             throw new IllegalArgumentException("Cannot insert null into the heap.");
         }
 
         this.data.add(item);
-        map.put(item, this.data.size() - 1); //
+        map.put(item, this.data.size() - 1);
         upHeapify(this.data.size() - 1);
     }
 
+    /**
+     * Restores the heap property by moving the item at the given index upwards.
+     *
+     * @param ci the index of the current item
+     */
     private void upHeapify(int ci) {
         int pi = (ci - 1) / 2;
-        if (isLarger(this.data.get(ci), this.data.get(pi)) > 0) {
+        if (ci > 0 && isLarger(this.data.get(ci), this.data.get(pi)) > 0) {
             swap(pi, ci);
             upHeapify(pi);
         }
     }
 
-    public void display() {
-        System.out.println(this.data);
-    }
-
+    /**
+     * Returns the number of elements in the heap.
+     *
+     * @return the size of the heap
+     */
     public int size() {
         return this.data.size();
     }
 
+    /**
+     * Checks if the heap is empty.
+     *
+     * @return true if the heap is empty, false otherwise
+     */
     public boolean isEmpty() {
         return this.size() == 0;
     }
 
+    /**
+     * Removes and returns the maximum item from the heap.
+     *
+     * @return the maximum item
+     */
     public T remove() {
+        if (isEmpty()) {
+            throw new IllegalStateException("Heap is empty");
+        }
         this.swap(0, this.size() - 1);
         T rv = this.data.remove(this.size() - 1);
-        downHeapify(0);
         map.remove(rv);
+        downHeapify(0);
         return rv;
     }
 
+    /**
+     * Restores the heap property by moving the item at the given index downwards.
+     *
+     * @param pi the index of the current item
+     */
     private void downHeapify(int pi) {
         int lci = 2 * pi + 1;
         int rci = 2 * pi + 2;
@@ -62,15 +96,35 @@ private void downHeapify(int pi) {
         }
     }
 
+    /**
+     * Retrieves the maximum item from the heap without removing it.
+     *
+     * @return the maximum item
+     */
     public T get() {
-        return this.data.get(0);
+        if (isEmpty()) {
+            throw new IllegalStateException("Heap is empty");
+        }
+        return this.data.getFirst();
     }
 
-    // t has higher property then return +ve
+    /**
+     * Compares two items to determine their order.
+     *
+     * @param t the first item
+     * @param o the second item
+     * @return a positive integer if t is greater than o, negative if t is less, and zero if they are equal
+     */
     private int isLarger(T t, T o) {
         return t.compareTo(o);
     }
 
+    /**
+     * Swaps two items in the heap and updates their indices in the map.
+     *
+     * @param i index of the first item
+     * @param j index of the second item
+     */
     private void swap(int i, int j) {
         T ith = this.data.get(i);
         T jth = this.data.get(j);
@@ -80,9 +134,16 @@ private void swap(int i, int j) {
         map.put(jth, i);
     }
 
+    /**
+     * Updates the priority of the specified item by restoring the heap property.
+     *
+     * @param item the item whose priority is to be updated
+     */
     public void updatePriority(T item) {
+        if (!map.containsKey(item)) {
+            throw new IllegalArgumentException("Item not found in the heap");
+        }
         int index = map.get(item);
-        // because we enter lesser value then old vale
         upHeapify(index);
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java
index 8915a6d8aef2..a3642996b769 100644
--- a/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java
@@ -13,114 +13,73 @@ public class GenericHeapTest {
     private GenericHeap<Integer> heap;
 
     @BeforeEach
-    public void setUp() {
+    void setUp() {
         heap = new GenericHeap<>();
     }
 
     @Test
-    public void testGenericHeapAddAndGet() {
-        heap.add(19);
-        heap.add(36);
-        heap.add(100);
-        heap.add(-17);
-        heap.add(3);
-
-        // Check that the largest element (100) is at the top of the heap
-        assertEquals(100, heap.get());
-    }
-
-    @Test
-    public void testGenericHeapRemove() {
-        heap.add(19);
-        heap.add(36);
-        heap.add(100);
-        heap.add(-17);
-        heap.add(3);
-
-        // Verify that the largest element is removed correctly
-        assertEquals(100, heap.remove());
-
-        // The new element at the top should be 36
-        assertEquals(36, heap.get());
+    void testAddAndGet() {
+        heap.add(10);
+        heap.add(20);
+        heap.add(5);
 
-        // Check that the size is correct after removal
-        assertEquals(4, heap.size());
+        assertEquals(20, heap.get());
     }
 
     @Test
-    public void testGenericHeapSize() {
-        assertTrue(heap.isEmpty());
-
+    void testRemove() {
         heap.add(10);
         heap.add(20);
+        heap.add(5);
 
-        // Check that the size is correct
-        assertEquals(2, heap.size());
-
-        heap.remove();
-
-        // After removal, the size should be 1
-        assertEquals(1, heap.size());
+        assertEquals(20, heap.remove());
+        assertEquals(10, heap.get());
     }
 
     @Test
-    public void testGenericHeapIsEmpty() {
-        // Verify that the heap is initially empty
+    void testIsEmpty() {
         assertTrue(heap.isEmpty());
-
-        heap.add(15);
-
-        // Now the heap should not be empty
+        heap.add(1);
         assertFalse(heap.isEmpty());
-
-        heap.remove();
-
-        // After removing the one element, it should be empty again
-        assertTrue(heap.isEmpty());
     }
 
     @Test
-    public void testGenericHeapUpdatePriority() {
-        heap.add(19);
-        heap.add(36);
-        heap.add(100);
-        heap.add(-17);
-        heap.add(3);
-
-        // Verify that the largest element initially is 100
-        assertEquals(100, heap.get());
+    void testSize() {
+        assertEquals(0, heap.size());
+        heap.add(1);
+        heap.add(2);
+        assertEquals(2, heap.size());
+    }
 
-        heap.remove();
+    @Test
+    void testUpdatePriority() {
+        heap.add(10);
+        heap.add(20);
+        heap.add(5);
 
-        // Simulates a change in priority by increasing the value of 100 to 44
-        heap.add(44);
+        heap.updatePriority(10);
+        assertEquals(20, heap.get());
 
-        // Now, the new high should be 25
-        assertEquals(44, heap.get());
+        heap.add(30);
+        heap.updatePriority(20); // 20 will be moved up
+        assertEquals(30, heap.get());
     }
 
     @Test
-    public void testGenericHeapRemoveUntilEmpty() {
-        heap.add(5);
-        heap.add(3);
-        heap.add(4);
-        heap.add(1);
-        heap.add(2);
-
-        // Remove all items and check that they are removed in descending order
-        assertEquals(5, heap.remove());
-        assertEquals(4, heap.remove());
-        assertEquals(3, heap.remove());
-        assertEquals(2, heap.remove());
-        assertEquals(1, heap.remove());
+    void testRemoveFromEmptyHeap() {
+        Exception exception = assertThrows(IllegalStateException.class, () -> heap.remove());
+        assertEquals("Heap is empty", exception.getMessage());
+    }
 
-        // Empty heap
-        assertTrue(heap.isEmpty());
+    @Test
+    void testGetFromEmptyHeap() {
+        Exception exception = assertThrows(IllegalStateException.class, () -> heap.get());
+        assertEquals("Heap is empty", exception.getMessage());
     }
 
     @Test
-    public void testGenericHeapAddNullItem() {
-        // Check null item
-        assertThrows(IllegalArgumentException.class, () -> { heap.add(null); });
+    void testUpdatePriorityForNonExistentItem() {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> heap.updatePriority(100));
+        assertEquals("Item not found in the heap", exception.getMessage());
     }
 }

From 857d921b07f3ee0d4b58d268e7cab40ed8275e68 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 30 Oct 2024 01:52:31 +0530
Subject: [PATCH 0709/1338] Enhance docs, add tests in `ReverseKGroup` (#5999)

---
 .../datastructures/lists/ReverseKGroup.java   | 57 +++++++++++++++++--
 .../lists/ReverseKGroupTest.java              |  1 +
 2 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java b/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
index 3c4b9331266c..c9a5c1df9870 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
@@ -1,11 +1,43 @@
 package com.thealgorithms.datastructures.lists;
 
 /**
- * Reverse K Group LinkedList (https://www.topcoder.com/thrive/articles/reverse-node-in-k-group)
+ * The ReverseKGroup class provides functionality to reverse nodes in a
+ * linked list in groups of k nodes.
+ * <p>
+ * This algorithm follows the approach of reversing the linked list in segments of
+ * size k. If the remaining nodes are fewer than k, they remain unchanged.
+ * </p>
+ * <p>
+ * Example:
+ * Given a linked list: 1 -> 2 -> 3 -> 4 -> 5 and k = 3,
+ * the output will be: 3 -> 2 -> 1 -> 4 -> 5.
+ * </p>
+ * <p>
+ * The implementation contains:
+ * - {@code length(Node head)}: A method to calculate the length of the linked list.
+ * - {@code reverse(Node head, int count, int k)}: A helper method that reverses the nodes
+ *   in the linked list in groups of k.
+ * - {@code reverseKGroup(Node head, int k)}: The main method that initiates the reversal
+ *   process by calling the reverse method.
+ * </p>
+ * <p>
+ * Complexity:
+ * <ul>
+ *   <li>Time Complexity: O(n), where n is the number of nodes in the linked list.</li>
+ *   <li>Space Complexity: O(1), as we are reversing in place.</li>
+ * </ul>
+ * </p>
+ *
  * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
  */
-
 public class ReverseKGroup {
+
+    /**
+     * Calculates the length of the linked list.
+     *
+     * @param head The head node of the linked list.
+     * @return The total number of nodes in the linked list.
+     */
     public int length(Node head) {
         Node curr = head;
         int count = 0;
@@ -15,7 +47,15 @@ public int length(Node head) {
         }
         return count;
     }
-    // reverse function
+
+    /**
+     * Reverses the linked list in groups of k nodes.
+     *
+     * @param head The head node of the linked list.
+     * @param count The remaining number of nodes.
+     * @param k The size of the group to reverse.
+     * @return The new head of the reversed linked list segment.
+     */
     public Node reverse(Node head, int count, int k) {
         if (count < k) {
             return head;
@@ -37,9 +77,16 @@ public Node reverse(Node head, int count, int k) {
         }
         return prev;
     }
+
+    /**
+     * Reverses the linked list in groups of k nodes.
+     *
+     * @param head The head node of the linked list.
+     * @param k The size of the group to reverse.
+     * @return The head of the modified linked list after reversal.
+     */
     public Node reverseKGroup(Node head, int k) {
         int count = length(head);
-        Node ans = reverse(head, count, k);
-        return ans;
+        return reverse(head, count, k);
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java b/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
index e7e3cca4083f..b2db478f692c 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
@@ -4,6 +4,7 @@
 import static org.junit.jupiter.api.Assertions.assertNull;
 
 import org.junit.jupiter.api.Test;
+
 /**
  * Test cases for Reverse K Group LinkedList
  * Author: Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)

From b14db816bdf73db25812f91b507d0c88160fdadf Mon Sep 17 00:00:00 2001
From: Rashi Dashore <119104356+rashi07dashore@users.noreply.github.com>
Date: Wed, 30 Oct 2024 02:00:22 +0530
Subject: [PATCH 0710/1338] Add shuffle array (#6026)

---
 .../com/thealgorithms/misc/ShuffleArray.java  | 38 +++++++++
 .../thealgorithms/misc/ShuffleArrayTest.java  | 84 +++++++++++++++++++
 2 files changed, 122 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/misc/ShuffleArray.java
 create mode 100644 src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java

diff --git a/src/main/java/com/thealgorithms/misc/ShuffleArray.java b/src/main/java/com/thealgorithms/misc/ShuffleArray.java
new file mode 100644
index 000000000000..65d38adfc37a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/misc/ShuffleArray.java
@@ -0,0 +1,38 @@
+package com.thealgorithms.misc;
+
+import java.util.Random;
+
+/**
+ * The Fisher-Yates (Knuth) Shuffle algorithm randomly permutes an array's
+ * elements, ensuring each permutation is equally likely.
+ *
+ * <p>
+ * Worst-case performance O(n)
+ * Best-case performance O(n)
+ * Average performance O(n)
+ * Worst-case space complexity O(1)
+ *
+ * This class provides a static method to shuffle an array in place.
+ *
+ * @author Rashi Dashore (https://github.com/rashi07dashore)
+ */
+public final class ShuffleArray {
+    // Prevent instantiation
+    private ShuffleArray() {
+    }
+
+    /**
+     * This method shuffles an array using the Fisher-Yates algorithm.
+     *
+     * @param arr is the input array to be shuffled
+     */
+    public static void shuffle(int[] arr) {
+        Random random = new Random();
+        for (int i = arr.length - 1; i > 0; i--) {
+            int j = random.nextInt(i + 1);
+            int temp = arr[i];
+            arr[i] = arr[j];
+            arr[j] = temp;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java b/src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java
new file mode 100644
index 000000000000..915b83e376b6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java
@@ -0,0 +1,84 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class ShuffleArrayTest {
+
+    @Test
+    void testShuffleBasic() {
+        int[] arr = {1, 2, 3, 4, 5};
+        int[] originalArr = arr.clone(); // Clone original array for comparison
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is not the same as the original
+        assertNotEquals(originalArr, arr);
+    }
+
+    @Test
+    void testShuffleSingleElement() {
+        int[] arr = {1};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is the same as the original
+        assertArrayEquals(originalArr, arr);
+    }
+
+    @Test
+    void testShuffleTwoElements() {
+        int[] arr = {1, 2};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is not the same as the original
+        assertNotEquals(originalArr, arr);
+        // Check that the shuffled array still contains the same elements
+        assertTrue(arr[0] == 1 || arr[0] == 2);
+        assertTrue(arr[1] == 1 || arr[1] == 2);
+    }
+
+    @Test
+    void testShuffleEmptyArray() {
+        int[] arr = {};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is the same as the original (still empty)
+        assertArrayEquals(originalArr, arr);
+    }
+
+    @Test
+    void testShuffleLargeArray() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is not the same as the original
+        assertNotEquals(originalArr, arr);
+    }
+
+    @Test
+    void testShuffleRetainsElements() {
+        int[] arr = {1, 2, 3, 4, 5};
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array contains the same elements
+        assertTrue(arr.length == 5);
+        for (int i = 1; i <= 5; i++) {
+            assertTrue(contains(arr, i));
+        }
+    }
+
+    private boolean contains(int[] arr, int value) {
+        for (int num : arr) {
+            if (num == value) {
+                return true;
+            }
+        }
+        return false;
+    }
+}

From 03bb8ee66ef479422e68899f05a36ffc2d77d69d Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 30 Oct 2024 02:17:33 +0530
Subject: [PATCH 0711/1338] Enhance docs, add tests in `MaxHeap` (#5983)

---
 DIRECTORY.md                                  |   3 +
 .../datastructures/heaps/HeapElement.java     |   7 +-
 .../datastructures/heaps/MaxHeap.java         | 225 +++++++++++++-----
 .../datastructures/heaps/MaxHeapTest.java     | 144 +++++++++++
 4 files changed, 321 insertions(+), 58 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/heaps/MaxHeapTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 0f7184cdb7e5..01e031b58581 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -488,6 +488,7 @@
             * [PalindromePrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromePrime.java)
             * [PalindromeSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java)
             * [RangeInSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java)
+            * [ShuffleArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ShuffleArray.java)
             * [Sparsity](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sparsity.java)
             * [ThreeSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java)
             * [TwoSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/TwoSumProblem.java)
@@ -876,6 +877,7 @@
               * [HeapElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java)
               * [KthElementFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java)
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
+              * [MaxHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MaxHeapTest.java)
               * [MedianFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java)
               * [MergeKSortedArraysTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MergeKSortedArraysTest.java)
               * [MinHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MinHeapTest.java)
@@ -1136,6 +1138,7 @@
             * [PalindromePrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java)
             * [PalindromeSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java)
             * [RangeInSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java)
+            * [ShuffleArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java)
             * [SparsityTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/SparsityTest.java)
             * [ThreeSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java)
             * [TwoSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java b/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java
index 57cc9e37122d..a9cfac7036eb 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java
@@ -143,10 +143,9 @@ public String toString() {
     }
 
     /**
-     * Compares this heap element to another object for equality.
-     *
-     * @param o the object to compare with
-     * @return true if the keys and additional information are identical, false otherwise
+     * @param o : an object to compare with the current element
+     * @return true if the keys on both elements are identical and the
+     * additional info objects are identical.
      */
     @Override
     public boolean equals(Object o) {
diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
index 9010aae4cae5..5b4b29cf1c2d 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java
@@ -4,128 +4,245 @@
 import java.util.List;
 
 /**
- * Heap tree where a node's key is higher than or equal to its parent's and
- * lower than or equal to its children's.
+ * A Max Heap implementation where each node's key is higher than or equal to its children's keys.
+ * This data structure provides O(log n) time complexity for insertion and deletion operations,
+ * and O(1) for retrieving the maximum element.
+ *
+ * Properties:
+ * 1. Complete Binary Tree
+ * 2. Parent node's key ≥ Children nodes' keys
+ * 3. Root contains the maximum element
+ *
+ * Example usage:
+ * <pre>
+ * List<HeapElement> elements = Arrays.asList(
+ *     new HeapElement(5, "Five"),
+ *     new HeapElement(2, "Two")
+ * );
+ * MaxHeap heap = new MaxHeap(elements);
+ * heap.insertElement(new HeapElement(7, "Seven"));
+ * HeapElement max = heap.getElement(); // Returns and removes the maximum element
+ * </pre>
  *
  * @author Nicolas Renard
  */
 public class MaxHeap implements Heap {
 
+    /** The internal list that stores heap elements */
     private final List<HeapElement> maxHeap;
 
+    /**
+     * Constructs a new MaxHeap from a list of elements.
+     * Null elements in the input list are ignored.
+     *
+     * @param listElements List of HeapElement objects to initialize the heap
+     * @throws IllegalArgumentException if the input list is null
+     */
     public MaxHeap(List<HeapElement> listElements) {
+        if (listElements == null) {
+            throw new IllegalArgumentException("Input list cannot be null");
+        }
+
         maxHeap = new ArrayList<>();
+
+        // Safe initialization: directly add non-null elements first
         for (HeapElement heapElement : listElements) {
             if (heapElement != null) {
-                insertElement(heapElement);
-            } else {
-                System.out.println("Null element. Not added to heap");
+                maxHeap.add(heapElement);
             }
         }
-        if (maxHeap.isEmpty()) {
-            System.out.println("No element has been added, empty heap.");
+
+        // Heapify the array bottom-up
+        for (int i = maxHeap.size() / 2; i >= 0; i--) {
+            heapifyDown(i + 1); // +1 because heapifyDown expects 1-based index
+        }
+    }
+
+    /**
+     * Maintains heap properties by moving an element down the heap.
+     * Similar to toggleDown but used specifically during initialization.
+     *
+     * @param elementIndex 1-based index of the element to heapify
+     */
+    private void heapifyDown(int elementIndex) {
+        int largest = elementIndex - 1;
+        int leftChild = 2 * elementIndex - 1;
+        int rightChild = 2 * elementIndex;
+
+        if (leftChild < maxHeap.size() && maxHeap.get(leftChild).getKey() > maxHeap.get(largest).getKey()) {
+            largest = leftChild;
+        }
+
+        if (rightChild < maxHeap.size() && maxHeap.get(rightChild).getKey() > maxHeap.get(largest).getKey()) {
+            largest = rightChild;
+        }
+
+        if (largest != elementIndex - 1) {
+            HeapElement swap = maxHeap.get(elementIndex - 1);
+            maxHeap.set(elementIndex - 1, maxHeap.get(largest));
+            maxHeap.set(largest, swap);
+
+            heapifyDown(largest + 1);
         }
     }
 
     /**
-     * Get the element at a given index. The key for the list is equal to index
-     * value - 1
+     * Retrieves the element at the specified index without removing it.
+     * Note: The index is 1-based for consistency with heap operations.
      *
-     * @param elementIndex index
-     * @return heapElement
+     * @param elementIndex 1-based index of the element to retrieve
+     * @return HeapElement at the specified index
+     * @throws IndexOutOfBoundsException if the index is invalid
      */
     public HeapElement getElement(int elementIndex) {
         if ((elementIndex <= 0) || (elementIndex > maxHeap.size())) {
-            throw new IndexOutOfBoundsException("Index out of heap range");
+            throw new IndexOutOfBoundsException("Index " + elementIndex + " is out of heap range [1, " + maxHeap.size() + "]");
         }
         return maxHeap.get(elementIndex - 1);
     }
 
-    // Get the key of the element at a given index
+    /**
+     * Retrieves the key value of an element at the specified index.
+     *
+     * @param elementIndex 1-based index of the element
+     * @return double value representing the key
+     * @throws IndexOutOfBoundsException if the index is invalid
+     */
     private double getElementKey(int elementIndex) {
         if ((elementIndex <= 0) || (elementIndex > maxHeap.size())) {
-            throw new IndexOutOfBoundsException("Index out of heap range");
+            throw new IndexOutOfBoundsException("Index " + elementIndex + " is out of heap range [1, " + maxHeap.size() + "]");
         }
-
         return maxHeap.get(elementIndex - 1).getKey();
     }
 
-    // Swaps two elements in the heap
+    /**
+     * Swaps two elements in the heap.
+     *
+     * @param index1 1-based index of first element
+     * @param index2 1-based index of second element
+     */
     private void swap(int index1, int index2) {
         HeapElement temporaryElement = maxHeap.get(index1 - 1);
         maxHeap.set(index1 - 1, maxHeap.get(index2 - 1));
         maxHeap.set(index2 - 1, temporaryElement);
     }
 
-    // Toggle an element up to its right place as long as its key is lower than its parent's
+    /**
+     * Moves an element up the heap until heap properties are satisfied.
+     * This operation is called after insertion to maintain heap properties.
+     *
+     * @param elementIndex 1-based index of the element to move up
+     */
     private void toggleUp(int elementIndex) {
         double key = maxHeap.get(elementIndex - 1).getKey();
-        while (getElementKey((int) Math.floor(elementIndex / 2.0)) < key) {
+        while (elementIndex > 1 && getElementKey((int) Math.floor(elementIndex / 2.0)) < key) {
             swap(elementIndex, (int) Math.floor(elementIndex / 2.0));
             elementIndex = (int) Math.floor(elementIndex / 2.0);
         }
     }
 
-    // Toggle an element down to its right place as long as its key is higher
-    // than any of its children's
+    /**
+     * Moves an element down the heap until heap properties are satisfied.
+     * This operation is called after deletion to maintain heap properties.
+     *
+     * @param elementIndex 1-based index of the element to move down
+     */
     private void toggleDown(int elementIndex) {
         double key = maxHeap.get(elementIndex - 1).getKey();
-        boolean wrongOrder = (key < getElementKey(elementIndex * 2)) || (key < getElementKey(Math.min(elementIndex * 2, maxHeap.size())));
-        while ((2 * elementIndex <= maxHeap.size()) && wrongOrder) {
-            // Check whether it shall swap the element with its left child or its right one if any.
-            if ((2 * elementIndex < maxHeap.size()) && (getElementKey(elementIndex * 2 + 1) > getElementKey(elementIndex * 2))) {
-                swap(elementIndex, 2 * elementIndex + 1);
-                elementIndex = 2 * elementIndex + 1;
+        boolean wrongOrder = (2 * elementIndex <= maxHeap.size() && key < getElementKey(elementIndex * 2)) || (2 * elementIndex + 1 <= maxHeap.size() && key < getElementKey(elementIndex * 2 + 1));
+
+        while (2 * elementIndex <= maxHeap.size() && wrongOrder) {
+            int largerChildIndex;
+            if (2 * elementIndex + 1 <= maxHeap.size() && getElementKey(elementIndex * 2 + 1) > getElementKey(elementIndex * 2)) {
+                largerChildIndex = 2 * elementIndex + 1;
             } else {
-                swap(elementIndex, 2 * elementIndex);
-                elementIndex = 2 * elementIndex;
+                largerChildIndex = 2 * elementIndex;
             }
-            wrongOrder = (key < getElementKey(elementIndex * 2)) || (key < getElementKey(Math.min(elementIndex * 2, maxHeap.size())));
+
+            swap(elementIndex, largerChildIndex);
+            elementIndex = largerChildIndex;
+
+            wrongOrder = (2 * elementIndex <= maxHeap.size() && key < getElementKey(elementIndex * 2)) || (2 * elementIndex + 1 <= maxHeap.size() && key < getElementKey(elementIndex * 2 + 1));
         }
     }
 
-    private HeapElement extractMax() {
-        HeapElement result = maxHeap.get(0);
-        deleteElement(0);
+    /**
+     * Extracts and returns the maximum element from the heap.
+     *
+     * @return HeapElement with the highest key
+     * @throws EmptyHeapException if the heap is empty
+     */
+    private HeapElement extractMax() throws EmptyHeapException {
+        if (maxHeap.isEmpty()) {
+            throw new EmptyHeapException("Cannot extract from an empty heap");
+        }
+        HeapElement result = maxHeap.getFirst();
+        deleteElement(1);
         return result;
     }
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
-    public final void insertElement(HeapElement element) {
+    public void insertElement(HeapElement element) {
+        if (element == null) {
+            throw new IllegalArgumentException("Cannot insert null element");
+        }
         maxHeap.add(element);
         toggleUp(maxHeap.size());
     }
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
-    public void deleteElement(int elementIndex) {
+    public void deleteElement(int elementIndex) throws EmptyHeapException {
         if (maxHeap.isEmpty()) {
-            try {
-                throw new EmptyHeapException("Attempt to delete an element from an empty heap");
-            } catch (EmptyHeapException e) {
-                e.printStackTrace();
-            }
+            throw new EmptyHeapException("Cannot delete from an empty heap");
         }
         if ((elementIndex > maxHeap.size()) || (elementIndex <= 0)) {
-            throw new IndexOutOfBoundsException("Index out of heap range");
+            throw new IndexOutOfBoundsException("Index " + elementIndex + " is out of heap range [1, " + maxHeap.size() + "]");
         }
-        // The last element in heap replaces the one to be deleted
-        maxHeap.set(elementIndex - 1, getElement(maxHeap.size()));
-        maxHeap.remove(maxHeap.size());
-        // Shall the new element be moved up...
-        if (getElementKey(elementIndex) > getElementKey((int) Math.floor(elementIndex / 2.0))) {
-            toggleUp(elementIndex);
-        } // ... or down ?
-        else if (((2 * elementIndex <= maxHeap.size()) && (getElementKey(elementIndex) < getElementKey(elementIndex * 2))) || ((2 * elementIndex < maxHeap.size()) && (getElementKey(elementIndex) < getElementKey(elementIndex * 2)))) {
-            toggleDown(elementIndex);
+
+        // Replace with last element and remove last position
+        maxHeap.set(elementIndex - 1, maxHeap.getLast());
+        maxHeap.removeLast();
+
+        // No need to toggle if we just removed the last element
+        if (!maxHeap.isEmpty() && elementIndex <= maxHeap.size()) {
+            // Determine whether to toggle up or down
+            if (elementIndex > 1 && getElementKey(elementIndex) > getElementKey((int) Math.floor(elementIndex / 2.0))) {
+                toggleUp(elementIndex);
+            } else {
+                toggleDown(elementIndex);
+            }
         }
     }
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
     public HeapElement getElement() throws EmptyHeapException {
-        try {
-            return extractMax();
-        } catch (Exception e) {
-            throw new EmptyHeapException("Heap is empty. Error retrieving element", e);
-        }
+        return extractMax();
+    }
+
+    /**
+     * Returns the current size of the heap.
+     *
+     * @return number of elements in the heap
+     */
+    public int size() {
+        return maxHeap.size();
+    }
+
+    /**
+     * Checks if the heap is empty.
+     *
+     * @return true if the heap contains no elements
+     */
+    public boolean isEmpty() {
+        return maxHeap.isEmpty();
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/MaxHeapTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/MaxHeapTest.java
new file mode 100644
index 000000000000..c1b7eb3fd4ae
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/MaxHeapTest.java
@@ -0,0 +1,144 @@
+package com.thealgorithms.datastructures.heaps;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for MaxHeap implementation
+ */
+class MaxHeapTest {
+
+    private MaxHeap heap;
+
+    @BeforeEach
+    void setUp() {
+        // Create a fresh heap for each test
+        List<HeapElement> elements = Arrays.asList(new HeapElement(5.0, "Five"), new HeapElement(2.0, "Two"), new HeapElement(8.0, "Eight"), new HeapElement(1.0, "One"), new HeapElement(9.0, "Nine"));
+        heap = new MaxHeap(elements);
+    }
+
+    @Test
+    void testConstructorWithNullList() {
+        assertThrows(IllegalArgumentException.class, () -> new MaxHeap(null));
+    }
+
+    @Test
+    void testConstructorWithEmptyList() {
+        MaxHeap emptyHeap = new MaxHeap(new ArrayList<>());
+        assertTrue(emptyHeap.isEmpty());
+    }
+
+    @Test
+    void testConstructorWithNullElements() {
+        List<HeapElement> elements = Arrays.asList(new HeapElement(1.0, "One"), null, new HeapElement(2.0, "Two"));
+        MaxHeap heap = new MaxHeap(elements);
+        assertEquals(2, heap.size());
+    }
+
+    @Test
+    void testInsertElement() {
+        heap.insertElement(new HeapElement(10.0, "Ten"));
+        assertEquals(10.0, heap.getElement(1).getKey());
+        assertEquals(6, heap.size());
+    }
+
+    @Test
+    void testInsertNullElement() {
+        assertThrows(IllegalArgumentException.class, () -> heap.insertElement(null));
+    }
+
+    @Test
+    void testGetElementAtIndex() {
+        HeapElement element = heap.getElement(1);
+        assertEquals(9.0, element.getKey());
+        assertEquals("Nine", element.getValue());
+    }
+
+    @Test
+    void testGetElementAtInvalidIndex() {
+        assertThrows(IndexOutOfBoundsException.class, () -> heap.getElement(0));
+        assertThrows(IndexOutOfBoundsException.class, () -> heap.getElement(10));
+    }
+
+    @Test
+    void testDeleteElement() throws EmptyHeapException {
+        heap.deleteElement(1);
+        assertEquals(8.0, heap.getElement(1).getKey());
+        assertEquals(4, heap.size());
+    }
+
+    @Test
+    void testDeleteElementAtInvalidIndex() {
+        assertThrows(IndexOutOfBoundsException.class, () -> heap.deleteElement(0));
+        assertThrows(IndexOutOfBoundsException.class, () -> heap.deleteElement(10));
+    }
+
+    @Test
+    void testDeleteFromEmptyHeap() {
+        MaxHeap emptyHeap = new MaxHeap(new ArrayList<>());
+        assertThrows(EmptyHeapException.class, () -> emptyHeap.deleteElement(1));
+    }
+
+    @Test
+    void testExtractMax() throws EmptyHeapException {
+        HeapElement max = heap.getElement();
+        assertEquals(9.0, max.getKey());
+        assertEquals("Nine", max.getValue());
+        assertEquals(4, heap.size());
+
+        max = heap.getElement();
+        assertEquals(8.0, max.getKey());
+        assertEquals(3, heap.size());
+    }
+
+    @Test
+    void testExtractMaxFromEmptyHeap() {
+        MaxHeap emptyHeap = new MaxHeap(new ArrayList<>());
+        assertThrows(EmptyHeapException.class, () -> emptyHeap.getElement());
+    }
+
+    @Test
+    void testHeapOrder() {
+        // Test that parent is always greater than or equal to children
+        for (int i = 1; i <= heap.size() / 2; i++) {
+            double parentKey = heap.getElement(i).getKey();
+
+            // Check left child
+            if (2 * i <= heap.size()) {
+                assertTrue(parentKey >= heap.getElement(2 * i).getKey());
+            }
+
+            // Check right child
+            if (2 * i + 1 <= heap.size()) {
+                assertTrue(parentKey >= heap.getElement(2 * i + 1).getKey());
+            }
+        }
+    }
+
+    @Test
+    void testSizeAndEmpty() {
+        assertEquals(5, heap.size());
+        assertFalse(heap.isEmpty());
+
+        // Remove all elements
+        while (!heap.isEmpty()) {
+            try {
+                heap.getElement();
+            } catch (EmptyHeapException e) {
+                Assertions.fail("Should not throw EmptyHeapException while heap is not empty");
+            }
+        }
+
+        assertEquals(0, heap.size());
+        assertTrue(heap.isEmpty());
+    }
+}

From a676ebc472a5d644c11ff127f7b99477abb28079 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 31 Oct 2024 23:58:37 +0200
Subject: [PATCH 0712/1338] Bump com.puppycrawl.tools:checkstyle from 10.19.0
 to 10.20.0 (#6076)

---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index de43d4fb0daf..7a0f5f4edcaf 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.19.0</version>
+                    <version>10.20.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 7b962a4a1d7611d0712743362b542cf3082cfb16 Mon Sep 17 00:00:00 2001
From: Shreya <95279016+Shreya123714@users.noreply.github.com>
Date: Fri, 1 Nov 2024 14:08:27 +0530
Subject: [PATCH 0713/1338] Add Exponential Moving Average Filter (#6075)

---
 .../thealgorithms/audiofilters/EMAFilter.java | 48 +++++++++++++++++++
 .../audiofilters/EMAFilterTest.java           | 41 ++++++++++++++++
 2 files changed, 89 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/audiofilters/EMAFilter.java
 create mode 100644 src/test/java/com/thealgorithms/audiofilters/EMAFilterTest.java

diff --git a/src/main/java/com/thealgorithms/audiofilters/EMAFilter.java b/src/main/java/com/thealgorithms/audiofilters/EMAFilter.java
new file mode 100644
index 000000000000..0dd23e937953
--- /dev/null
+++ b/src/main/java/com/thealgorithms/audiofilters/EMAFilter.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.audiofilters;
+
+/**
+ * Exponential Moving Average (EMA) Filter for smoothing audio signals.
+ *
+ * <p>This filter applies an exponential moving average to a sequence of audio
+ * signal values, making it useful for smoothing out rapid fluctuations.
+ * The smoothing factor (alpha) controls the degree of smoothing.
+ *
+ * <p>Based on the definition from
+ * <a href="https://en.wikipedia.org/wiki/Moving_average">Wikipedia link</a>.
+ */
+public class EMAFilter {
+    private final double alpha;
+    private double emaValue;
+    /**
+     * Constructs an EMA filter with a given smoothing factor.
+     *
+     * @param alpha Smoothing factor (0 < alpha <= 1)
+     * @throws IllegalArgumentException if alpha is not in (0, 1]
+     */
+    public EMAFilter(double alpha) {
+        if (alpha <= 0 || alpha > 1) {
+            throw new IllegalArgumentException("Alpha must be between 0 and 1.");
+        }
+        this.alpha = alpha;
+        this.emaValue = 0.0;
+    }
+    /**
+     * Applies the EMA filter to an audio signal array.
+     *
+     * @param audioSignal Array of audio samples to process
+     * @return Array of processed (smoothed) samples
+     */
+    public double[] apply(double[] audioSignal) {
+        if (audioSignal.length == 0) {
+            return new double[0];
+        }
+        double[] emaSignal = new double[audioSignal.length];
+        emaValue = audioSignal[0];
+        emaSignal[0] = emaValue;
+        for (int i = 1; i < audioSignal.length; i++) {
+            emaValue = alpha * audioSignal[i] + (1 - alpha) * emaValue;
+            emaSignal[i] = emaValue;
+        }
+        return emaSignal;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/audiofilters/EMAFilterTest.java b/src/test/java/com/thealgorithms/audiofilters/EMAFilterTest.java
new file mode 100644
index 000000000000..f2338d3d8296
--- /dev/null
+++ b/src/test/java/com/thealgorithms/audiofilters/EMAFilterTest.java
@@ -0,0 +1,41 @@
+package com.thealgorithms.audiofilters;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class EMAFilterTest {
+
+    @Test
+    public void testApplyBasicSignal() {
+        EMAFilter emaFilter = new EMAFilter(0.2);
+        double[] audioSignal = {0.1, 0.5, 0.8, 0.6, 0.3, 0.9, 0.4};
+        double[] expectedOutput = {0.1, 0.18, 0.304, 0.3632, 0.35056, 0.460448, 0.4483584};
+        double[] result = emaFilter.apply(audioSignal);
+        assertArrayEquals(expectedOutput, result, 1e-5);
+    }
+
+    @Test
+    public void testApplyEmptySignal() {
+        EMAFilter emaFilter = new EMAFilter(0.2);
+        double[] audioSignal = {};
+        double[] expectedOutput = {};
+        double[] result = emaFilter.apply(audioSignal);
+        assertArrayEquals(expectedOutput, result);
+    }
+
+    @Test
+    public void testAlphaBounds() {
+        EMAFilter emaFilterMin = new EMAFilter(0.01);
+        EMAFilter emaFilterMax = new EMAFilter(1.0);
+        double[] audioSignal = {1.0, 1.0, 1.0, 1.0};
+
+        // Minimal smoothing (alpha close to 0)
+        double[] resultMin = emaFilterMin.apply(audioSignal);
+        assertArrayEquals(audioSignal, resultMin, 1e-5);
+
+        // Maximum smoothing (alpha = 1, output should match input)
+        double[] resultMax = emaFilterMax.apply(audioSignal);
+        assertArrayEquals(audioSignal, resultMax, 1e-5);
+    }
+}

From df0c997e4bce827246ee9d93ec3b1fe3c55a4332 Mon Sep 17 00:00:00 2001
From: Strange Developer <79030489+mosbat@users.noreply.github.com>
Date: Fri, 1 Nov 2024 18:52:42 +0100
Subject: [PATCH 0714/1338] General performance improvement (#6078)

---
 .../java/com/thealgorithms/ciphers/AES.java   |  2 --
 .../thealgorithms/ciphers/AffineCipher.java   | 16 +++++++--------
 .../com/thealgorithms/ciphers/Blowfish.java   | 20 +++++++++----------
 .../conversions/AnyBaseToAnyBase.java         |  8 ++++----
 .../conversions/HexaDecimalToBinary.java      |  6 ++++--
 .../datastructures/graphs/FloydWarshall.java  |  4 +---
 .../lists/SinglyLinkedList.java               |  2 +-
 .../datastructures/trees/GenericTree.java     |  3 +--
 .../StronglyConnectedComponentOptimized.java  |  2 ++
 .../thealgorithms/maths/NthUglyNumber.java    |  5 +++--
 .../thealgorithms/maths/VampireNumber.java    |  3 +--
 .../NonPreemptivePriorityScheduling.java      |  5 ++---
 .../backtracking/NQueensTest.java             |  3 ++-
 .../bitmanipulation/GenerateSubsetsTest.java  | 13 ++++++------
 .../datastructures/graphs/AStarTest.java      |  3 ++-
 .../dynamicprogramming/AllConstructTest.java  |  8 +++++---
 .../AssignmentUsingBitmaskTest.java           |  7 ++++---
 ...ronglyConnectedComponentOptimizedTest.java |  2 ++
 .../ActivitySelectionTest.java                |  4 +++-
 .../greedyalgorithms/CoinChangeTest.java      |  4 +++-
 .../maths/ChineseRemainderTheoremTest.java    |  5 +++--
 .../com/thealgorithms/maths/MeansTest.java    |  3 +--
 ...atrixtest.java => MedianOfMatrixTest.java} |  2 +-
 .../others/FloydTriangleTest.java             | 14 +++++++------
 .../CircularLookSchedulingTest.java           |  5 +++--
 .../CircularScanSchedulingTest.java           |  5 +++--
 .../diskscheduling/LookSchedulingTest.java    |  5 +++--
 .../diskscheduling/ScanSchedulingTest.java    |  5 +++--
 .../thealgorithms/strings/WordLadderTest.java |  3 ++-
 29 files changed, 92 insertions(+), 75 deletions(-)
 rename src/test/java/com/thealgorithms/misc/{MedianOfMatrixtest.java => MedianOfMatrixTest.java} (96%)

diff --git a/src/main/java/com/thealgorithms/ciphers/AES.java b/src/main/java/com/thealgorithms/ciphers/AES.java
index 5d614afbe584..1c283f6b7655 100644
--- a/src/main/java/com/thealgorithms/ciphers/AES.java
+++ b/src/main/java/com/thealgorithms/ciphers/AES.java
@@ -2418,8 +2418,6 @@ public static BigInteger scheduleCore(BigInteger t, int rconCounter) {
             rBytes = new StringBuilder(rBytes.substring(0, i * 2) + currentByteBits + rBytes.substring((i + 1) * 2));
         }
 
-        // t = new BigInteger(rBytes, 16);
-        // return t;
         return new BigInteger(rBytes.toString(), 16);
     }
 
diff --git a/src/main/java/com/thealgorithms/ciphers/AffineCipher.java b/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
index 636323b63646..b82681372f2b 100644
--- a/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
@@ -34,19 +34,19 @@ private AffineCipher() {
      */
     static String encryptMessage(char[] msg) {
         // Cipher Text initially empty
-        String cipher = "";
+        StringBuilder cipher = new StringBuilder();
         for (int i = 0; i < msg.length; i++) {
             // Avoid space to be encrypted
             /* applying encryption formula ( a * x + b ) mod m
             {here x is msg[i] and m is 26} and added 'A' to
             bring it in the range of ASCII alphabet [65-90 | A-Z] */
             if (msg[i] != ' ') {
-                cipher += (char) ((((a * (msg[i] - 'A')) + b) % 26) + 'A');
+                cipher.append((char) ((((a * (msg[i] - 'A')) + b) % 26) + 'A'));
             } else { // else simply append space character
-                cipher += msg[i];
+                cipher.append(msg[i]);
             }
         }
-        return cipher;
+        return cipher.toString();
     }
 
     /**
@@ -56,7 +56,7 @@ static String encryptMessage(char[] msg) {
      * @return the decrypted plaintext message
      */
     static String decryptCipher(String cipher) {
-        String msg = "";
+        StringBuilder msg = new StringBuilder();
         int aInv = 0;
         int flag;
 
@@ -75,13 +75,13 @@ static String decryptCipher(String cipher) {
             {here x is cipher[i] and m is 26} and added 'A'
             to bring it in the range of ASCII alphabet [65-90 | A-Z] */
             if (cipher.charAt(i) != ' ') {
-                msg += (char) (((aInv * ((cipher.charAt(i) - 'A') - b + 26)) % 26) + 'A');
+                msg.append((char) (((aInv * ((cipher.charAt(i) - 'A') - b + 26)) % 26) + 'A'));
             } else { // else simply append space character
-                msg += cipher.charAt(i);
+                msg.append(cipher.charAt(i));
             }
         }
 
-        return msg;
+        return msg.toString();
     }
 
     // Driver code
diff --git a/src/main/java/com/thealgorithms/ciphers/Blowfish.java b/src/main/java/com/thealgorithms/ciphers/Blowfish.java
index f6a0a3753e9b..ea1807e62710 100644
--- a/src/main/java/com/thealgorithms/ciphers/Blowfish.java
+++ b/src/main/java/com/thealgorithms/ciphers/Blowfish.java
@@ -1078,7 +1078,7 @@ public class Blowfish {
      * @return String object which is a binary representation of the hex number passed as parameter
      */
     private String hexToBin(String hex) {
-        String binary = "";
+        StringBuilder binary = new StringBuilder();
         long num;
         String binary4B;
         int n = hex.length();
@@ -1089,9 +1089,9 @@ private String hexToBin(String hex) {
             binary4B = "0000" + binary4B;
 
             binary4B = binary4B.substring(binary4B.length() - 4);
-            binary += binary4B;
+            binary.append(binary4B);
         }
-        return binary;
+        return binary.toString();
     }
 
     /**
@@ -1103,12 +1103,12 @@ private String hexToBin(String hex) {
      */
     private String binToHex(String binary) {
         long num = Long.parseUnsignedLong(binary, 2);
-        String hex = Long.toHexString(num);
+        StringBuilder hex = new StringBuilder(Long.toHexString(num));
         while (hex.length() < (binary.length() / 4)) {
-            hex = "0" + hex;
+            hex.insert(0, "0");
         }
 
-        return hex;
+        return hex.toString();
     }
 
     /**
@@ -1121,12 +1121,12 @@ private String binToHex(String binary) {
     private String xor(String a, String b) {
         a = hexToBin(a);
         b = hexToBin(b);
-        String ans = "";
+        StringBuilder ans = new StringBuilder();
         for (int i = 0; i < a.length(); i++) {
-            ans += (char) (((a.charAt(i) - '0') ^ (b.charAt(i) - '0')) + '0');
+            ans.append((char) (((a.charAt(i) - '0') ^ (b.charAt(i) - '0')) + '0'));
         }
-        ans = binToHex(ans);
-        return ans;
+        ans = new StringBuilder(binToHex(ans.toString()));
+        return ans.toString();
     }
 
     /**
diff --git a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
index 4bd9c74a1751..7a9448fd8fe7 100644
--- a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
+++ b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
@@ -136,7 +136,7 @@ public static String base2base(String n, int b1, int b2) {
         int decimalValue = 0;
         int charB2;
         char charB1;
-        String output = "";
+        StringBuilder output = new StringBuilder();
         // Go through every character of n
         for (int i = 0; i < n.length(); i++) {
             // store the character in charB1
@@ -167,15 +167,15 @@ public static String base2base(String n, int b1, int b2) {
             // If the remainder is a digit < 10, simply add it to
             // the left side of the new number.
             if (decimalValue % b2 < 10) {
-                output = decimalValue % b2 + output;
+                output.insert(0, decimalValue % b2);
             } // If the remainder is >= 10, add a character with the
             // corresponding value to the new number. (A = 10, B = 11, C = 12, ...)
             else {
-                output = (char) ((decimalValue % b2) + 55) + output;
+                output.insert(0, (char) ((decimalValue % b2) + 55));
             }
             // Divide by the new base again
             decimalValue /= b2;
         }
-        return output;
+        return output.toString();
     }
 }
diff --git a/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java b/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
index 07acefc9fb14..c0eb9a01ba17 100644
--- a/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
+++ b/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java
@@ -52,9 +52,11 @@ public String convert(String numHex) {
      */
     public String completeDigits(String binNum) {
         final int byteSize = 8;
-        while (binNum.length() < byteSize) {
-            binNum = "0" + binNum;
+        StringBuilder binNumBuilder = new StringBuilder(binNum);
+        while (binNumBuilder.length() < byteSize) {
+            binNumBuilder.insert(0, "0");
         }
+        binNum = binNumBuilder.toString();
         return binNum;
     }
 }
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java b/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
index 66dc6782a8be..e5e673a21794 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java
@@ -42,9 +42,7 @@ public FloydWarshall(int numberofvertices) {
     public void floydwarshall(int[][] adjacencyMatrix) {
         // Initialize the distance matrix with the adjacency matrix.
         for (int source = 1; source <= numberofvertices; source++) {
-            for (int destination = 1; destination <= numberofvertices; destination++) {
-                distanceMatrix[source][destination] = adjacencyMatrix[source][destination];
-            }
+            System.arraycopy(adjacencyMatrix[source], 1, distanceMatrix[source], 1, numberofvertices);
         }
         for (int intermediate = 1; intermediate <= numberofvertices; intermediate++) {
             for (int source = 1; source <= numberofvertices; source++) {
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
index d5d3f31f4b66..eb6cdf48f58b 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
@@ -403,7 +403,7 @@ public static void main(String[] arg) {
         SinglyLinkedList list = new SinglyLinkedList();
         assert list.isEmpty();
         assert list.size() == 0 && list.count() == 0;
-        assert list.toString().equals("");
+        assert list.toString().isEmpty();
 
         /* Test insert function */
         list.insertHead(5);
diff --git a/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java b/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java
index a2e36f33dd4b..7d969a59def0 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java
@@ -23,6 +23,7 @@ private static final class Node {
     }
 
     private final Node root;
+
     public GenericTree() { // Constructor
         Scanner scn = new Scanner(System.in);
         root = createTreeG(null, 0, scn);
@@ -225,8 +226,6 @@ private void removeleaves(Node node) {
         for (int i = 0; i < node.child.size(); i++) {
             if (node.child.get(i).child.size() == 0) {
                 arr.add(i);
-                // node.child.remove(i);
-                // i--;
             } else {
                 removeleaves(node.child.get(i));
             }
diff --git a/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java b/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java
index 87d4e89d2c8c..ba75b2f4b1b8 100644
--- a/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java
+++ b/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java
@@ -1,3 +1,5 @@
+package com.thealgorithms.graph;
+
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
diff --git a/src/main/java/com/thealgorithms/maths/NthUglyNumber.java b/src/main/java/com/thealgorithms/maths/NthUglyNumber.java
index 6484026c14dd..2da22c4c8696 100644
--- a/src/main/java/com/thealgorithms/maths/NthUglyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/NthUglyNumber.java
@@ -1,7 +1,8 @@
 package com.thealgorithms.maths;
 
+import static java.util.Collections.singletonList;
+
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Map;
 import org.apache.commons.lang3.tuple.MutablePair;
 
@@ -16,7 +17,7 @@
  *     - the base [2, 3, 5] ugly numbers are the same as base [5, 6, 2, 3, 5] ugly numbers
  */
 public class NthUglyNumber {
-    private ArrayList<Long> uglyNumbers = new ArrayList<>(Arrays.asList(1L));
+    private ArrayList<Long> uglyNumbers = new ArrayList<>(singletonList(1L));
     private ArrayList<MutablePair<Integer, Integer>> positions = new ArrayList<>();
 
     /**
diff --git a/src/main/java/com/thealgorithms/maths/VampireNumber.java b/src/main/java/com/thealgorithms/maths/VampireNumber.java
index d64c82c6e68e..8820f8a23f70 100644
--- a/src/main/java/com/thealgorithms/maths/VampireNumber.java
+++ b/src/main/java/com/thealgorithms/maths/VampireNumber.java
@@ -33,8 +33,7 @@ static void test(int startValue, int stopValue) {
                 // System.out.println(i+ " "+ j);
                 if (isVampireNumber(i, j, true)) {
                     countofRes++;
-                    res.append("" + countofRes + ": = ( " + i + "," + j + " = " + i * j + ")"
-                        + "\n");
+                    res.append("").append(countofRes).append(": = ( ").append(i).append(",").append(j).append(" = ").append(i * j).append(")").append("\n");
                 }
             }
         }
diff --git a/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java b/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java
index 1d8e2c5160ff..414de4b24e36 100644
--- a/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.scheduling;
 
+import java.util.Collections;
 import java.util.LinkedList;
 import java.util.PriorityQueue;
 import java.util.Queue;
@@ -72,9 +73,7 @@ public static Process[] scheduleProcesses(Process[] processes) {
         int index = 0;
         Process[] executionOrder = new Process[processes.length];
 
-        for (Process process : processes) {
-            waitingQueue.add(process);
-        }
+        Collections.addAll(waitingQueue, processes);
 
         while (!waitingQueue.isEmpty() || !pq.isEmpty()) {
             // Add processes that have arrived to the priority queue
diff --git a/src/test/java/com/thealgorithms/backtracking/NQueensTest.java b/src/test/java/com/thealgorithms/backtracking/NQueensTest.java
index 977e3dfae2ce..243133848ee2 100644
--- a/src/test/java/com/thealgorithms/backtracking/NQueensTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/NQueensTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.backtracking;
 
+import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
@@ -11,7 +12,7 @@ public class NQueensTest {
 
     @Test
     public void testNQueens1() {
-        List<List<String>> expected = Arrays.asList(Arrays.asList("Q"));
+        List<List<String>> expected = singletonList(singletonList("Q"));
         assertEquals(expected, NQueens.getNQueensArrangements(1));
     }
 
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java
index e3205d1d0dba..912d7e729ade 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.bitmanipulation;
 
+import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
@@ -14,8 +15,8 @@ void testGenerateSubsetsWithTwoElements() {
         int[] set = {1, 2};
         List<List<Integer>> expected = new ArrayList<>();
         expected.add(new ArrayList<>());
-        expected.add(Arrays.asList(1));
-        expected.add(Arrays.asList(2));
+        expected.add(singletonList(1));
+        expected.add(singletonList(2));
         expected.add(Arrays.asList(1, 2));
 
         List<List<Integer>> result = GenerateSubsets.generateSubsets(set);
@@ -27,7 +28,7 @@ void testGenerateSubsetsWithOneElement() {
         int[] set = {3};
         List<List<Integer>> expected = new ArrayList<>();
         expected.add(new ArrayList<>());
-        expected.add(Arrays.asList(3));
+        expected.add(singletonList(3));
 
         List<List<Integer>> result = GenerateSubsets.generateSubsets(set);
         assertEquals(expected, result);
@@ -38,10 +39,10 @@ void testGenerateSubsetsWithThreeElements() {
         int[] set = {4, 5, 6};
         List<List<Integer>> expected = new ArrayList<>();
         expected.add(new ArrayList<>());
-        expected.add(Arrays.asList(4));
-        expected.add(Arrays.asList(5));
+        expected.add(singletonList(4));
+        expected.add(singletonList(5));
         expected.add(Arrays.asList(4, 5));
-        expected.add(Arrays.asList(6));
+        expected.add(singletonList(6));
         expected.add(Arrays.asList(4, 6));
         expected.add(Arrays.asList(5, 6));
         expected.add(Arrays.asList(4, 5, 6));
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java
index dce5a6ed4b69..810773555a63 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.datastructures.graphs;
 
+import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
 
@@ -41,6 +42,6 @@ public void testAStarPathNotFound() {
     public void testAStarSameNode() {
         AStar.PathAndDistance result = AStar.aStar(0, 0, graph, heuristic);
         assertEquals(0, result.getDistance(), "Expected distance from 0 to 0 is 0");
-        assertEquals(Arrays.asList(0), result.getPath(), "Expected path should only contain the start node");
+        assertEquals(singletonList(0), result.getPath(), "Expected path should only contain the start node");
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java
index 4979327fbf2c..012876921c15 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.dynamicprogramming;
 
+import static java.util.Collections.emptyList;
+import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.Arrays;
@@ -10,7 +12,7 @@ public class AllConstructTest {
 
     @Test
     public void testAllConstructBasic() {
-        List<List<String>> expected = Arrays.asList(Arrays.asList("he", "l", "l", "o"));
+        List<List<String>> expected = singletonList(Arrays.asList("he", "l", "l", "o"));
         List<List<String>> result = AllConstruct.allConstruct("hello", Arrays.asList("he", "l", "o"));
         assertEquals(expected, result);
     }
@@ -24,14 +26,14 @@ public void testAllConstructMultipleWays() {
 
     @Test
     public void testAllConstructNoWays() {
-        List<List<String>> expected = Arrays.asList();
+        List<List<String>> expected = emptyList();
         List<List<String>> result = AllConstruct.allConstruct("abcdef", Arrays.asList("gh", "ijk"));
         assertEquals(expected, result);
     }
 
     @Test
     public void testAllConstructEmptyTarget() {
-        List<List<String>> expected = Arrays.asList(Arrays.asList());
+        List<List<String>> expected = singletonList(emptyList());
         List<List<String>> result = AllConstruct.allConstruct("", Arrays.asList("a", "b", "c"));
         assertEquals(expected, result);
     }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java
index 0258f3950510..eadc43ce59c5 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.dynamicprogramming;
 
+import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.Arrays;
@@ -23,7 +24,7 @@ public void testCountNoOfWays() {
     public void testNoPossibleAssignments() {
         int totalTasks = 3;
 
-        List<List<Integer>> taskPerformed = Arrays.asList(Arrays.asList(2), Arrays.asList(3));
+        List<List<Integer>> taskPerformed = Arrays.asList(singletonList(2), singletonList(3));
 
         AssignmentUsingBitmask assignment = new AssignmentUsingBitmask(taskPerformed, totalTasks);
         int ways = assignment.countNoOfWays();
@@ -34,7 +35,7 @@ public void testNoPossibleAssignments() {
     public void testSinglePersonMultipleTasks() {
         int totalTasks = 3;
 
-        List<List<Integer>> taskPerformed = Arrays.asList(Arrays.asList(1, 2, 3));
+        List<List<Integer>> taskPerformed = singletonList(Arrays.asList(1, 2, 3));
 
         AssignmentUsingBitmask assignment = new AssignmentUsingBitmask(taskPerformed, totalTasks);
         int ways = assignment.countNoOfWays();
@@ -45,7 +46,7 @@ public void testSinglePersonMultipleTasks() {
     public void testMultiplePeopleSingleTask() {
         int totalTasks = 1;
 
-        List<List<Integer>> taskPerformed = Arrays.asList(Arrays.asList(1), Arrays.asList(1));
+        List<List<Integer>> taskPerformed = Arrays.asList(singletonList(1), singletonList(1));
 
         AssignmentUsingBitmask assignment = new AssignmentUsingBitmask(taskPerformed, totalTasks);
         int ways = assignment.countNoOfWays();
diff --git a/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java b/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java
index 6f1c8a9d53b2..9473a328c982 100644
--- a/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java
+++ b/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java
@@ -1,3 +1,5 @@
+package com.thealgorithms.graph;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
index a997c198a39b..d24264a321bc 100644
--- a/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
@@ -1,9 +1,11 @@
 package com.thealgorithms.greedyalgorithms;
 
+import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import org.junit.jupiter.api.Test;
 
 public class ActivitySelectionTest {
@@ -24,7 +26,7 @@ public void testSingleActivity() {
         int[] end = {2};
 
         ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
-        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0));
+        List<Integer> expected = singletonList(0);
 
         assertEquals(expected, result);
     }
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java
index e9d267712a05..b9745be63088 100644
--- a/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java
@@ -1,9 +1,11 @@
 package com.thealgorithms.greedyalgorithms;
 
+import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import org.junit.jupiter.api.Test;
 
 public class CoinChangeTest {
@@ -16,7 +18,7 @@ public void testCoinChangeProblemWithValidAmount() {
 
     @Test
     public void testCoinChangeProblemWithLargeAmount() {
-        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(2000));
+        List<Integer> expected = singletonList(2000);
         ArrayList<Integer> coins = CoinChange.coinChangeProblem(2000);
         assertEquals(expected, coins);
     }
diff --git a/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java b/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java
index 31c676d6e7b4..7c153ae4cdda 100644
--- a/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java
+++ b/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.maths;
 
+import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.Arrays;
@@ -27,8 +28,8 @@ public void testCRTLargeModuli() {
 
     @Test
     public void testCRTWithSingleCongruence() {
-        List<Integer> remainders = Arrays.asList(4);
-        List<Integer> moduli = Arrays.asList(7);
+        List<Integer> remainders = singletonList(4);
+        List<Integer> moduli = singletonList(7);
         int expected = 4;
         int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
         assertEquals(expected, result);
diff --git a/src/test/java/com/thealgorithms/maths/MeansTest.java b/src/test/java/com/thealgorithms/maths/MeansTest.java
index bb2b4b6d1c50..4b3a5df44b34 100644
--- a/src/test/java/com/thealgorithms/maths/MeansTest.java
+++ b/src/test/java/com/thealgorithms/maths/MeansTest.java
@@ -59,8 +59,7 @@ void arithmeticMeanMultipleNumbers() {
 
     @Test
     void geometricMeanMultipleNumbers() {
-        LinkedList<Double> numbers = new LinkedList<>();
-        numbers.addAll(Lists.newArrayList(1d, 2d, 3d, 4d, 5d, 6d, 1.25));
+        LinkedList<Double> numbers = new LinkedList<>(Lists.newArrayList(1d, 2d, 3d, 4d, 5d, 6d, 1.25));
         assertEquals(2.6426195539300585, Means.geometric(numbers));
     }
 
diff --git a/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java b/src/test/java/com/thealgorithms/misc/MedianOfMatrixTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java
rename to src/test/java/com/thealgorithms/misc/MedianOfMatrixTest.java
index ec3a84b86c5b..19bc66857ae6 100644
--- a/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java
+++ b/src/test/java/com/thealgorithms/misc/MedianOfMatrixTest.java
@@ -7,7 +7,7 @@
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class MedianOfMatrixtest {
+public class MedianOfMatrixTest {
 
     @Test
     public void testMedianWithOddNumberOfElements() {
diff --git a/src/test/java/com/thealgorithms/others/FloydTriangleTest.java b/src/test/java/com/thealgorithms/others/FloydTriangleTest.java
index afa280c09838..b336ac4be51f 100644
--- a/src/test/java/com/thealgorithms/others/FloydTriangleTest.java
+++ b/src/test/java/com/thealgorithms/others/FloydTriangleTest.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.others;
 
+import static java.util.Collections.emptyList;
+import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.Arrays;
@@ -10,37 +12,37 @@ public class FloydTriangleTest {
 
     @Test
     public void testGenerateFloydTriangleWithValidInput() {
-        List<List<Integer>> expectedOutput = Arrays.asList(Arrays.asList(1), Arrays.asList(2, 3), Arrays.asList(4, 5, 6));
+        List<List<Integer>> expectedOutput = Arrays.asList(singletonList(1), Arrays.asList(2, 3), Arrays.asList(4, 5, 6));
         assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(3));
     }
 
     @Test
     public void testGenerateFloydTriangleWithOneRow() {
-        List<List<Integer>> expectedOutput = Arrays.asList(Arrays.asList(1));
+        List<List<Integer>> expectedOutput = singletonList(singletonList(1));
         assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(1));
     }
 
     @Test
     public void testGenerateFloydTriangleWithZeroRows() {
-        List<List<Integer>> expectedOutput = Arrays.asList();
+        List<List<Integer>> expectedOutput = emptyList();
         assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(0));
     }
 
     @Test
     public void testGenerateFloydTriangleWithNegativeRows() {
-        List<List<Integer>> expectedOutput = Arrays.asList();
+        List<List<Integer>> expectedOutput = emptyList();
         assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(-3));
     }
 
     @Test
     public void testGenerateFloydTriangleWithMultipleRows() {
-        List<List<Integer>> expectedOutput = Arrays.asList(Arrays.asList(1), Arrays.asList(2, 3), Arrays.asList(4, 5, 6), Arrays.asList(7, 8, 9, 10), Arrays.asList(11, 12, 13, 14, 15));
+        List<List<Integer>> expectedOutput = Arrays.asList(singletonList(1), Arrays.asList(2, 3), Arrays.asList(4, 5, 6), Arrays.asList(7, 8, 9, 10), Arrays.asList(11, 12, 13, 14, 15));
         assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(5));
     }
 
     @Test
     public void testGenerateFloydTriangleWithMoreMultipleRows() {
-        List<List<Integer>> expectedOutput = Arrays.asList(Arrays.asList(1), Arrays.asList(2, 3), Arrays.asList(4, 5, 6), Arrays.asList(7, 8, 9, 10), Arrays.asList(11, 12, 13, 14, 15), Arrays.asList(16, 17, 18, 19, 20, 21), Arrays.asList(22, 23, 24, 25, 26, 27, 28));
+        List<List<Integer>> expectedOutput = Arrays.asList(singletonList(1), Arrays.asList(2, 3), Arrays.asList(4, 5, 6), Arrays.asList(7, 8, 9, 10), Arrays.asList(11, 12, 13, 14, 15), Arrays.asList(16, 17, 18, 19, 20, 21), Arrays.asList(22, 23, 24, 25, 26, 27, 28));
         assertEquals(expectedOutput, FloydTriangle.generateFloydTriangle(7));
     }
 }
diff --git a/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java
index ae04e725cde5..55429e41b84d 100644
--- a/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.scheduling.diskscheduling;
 
+import static java.util.Collections.emptyList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.Arrays;
@@ -31,8 +32,8 @@ public void testCircularLookSchedulingMovingDown() {
     @Test
     public void testCircularLookSchedulingEmptyRequests() {
         CircularLookScheduling scheduling = new CircularLookScheduling(50, true, 200);
-        List<Integer> requests = Arrays.asList();
-        List<Integer> expected = Arrays.asList();
+        List<Integer> requests = emptyList();
+        List<Integer> expected = emptyList();
 
         List<Integer> result = scheduling.execute(requests);
         assertEquals(expected, result);
diff --git a/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java
index 06bd53c0b392..38daf5104b82 100644
--- a/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.scheduling.diskscheduling;
 
+import static java.util.Collections.emptyList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.Arrays;
@@ -39,8 +40,8 @@ public void testCircularScanSchedulingMovingDown() {
     @Test
     public void testCircularScanSchedulingEmptyRequests() {
         CircularScanScheduling circularScan = new CircularScanScheduling(50, true, 200);
-        List<Integer> requests = Arrays.asList();
-        List<Integer> expectedOrder = Arrays.asList();
+        List<Integer> requests = emptyList();
+        List<Integer> expectedOrder = emptyList();
 
         List<Integer> result = circularScan.execute(requests);
         assertEquals(expectedOrder, result);
diff --git a/src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java
index 91acc4837243..43ef1a698b55 100644
--- a/src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.scheduling.diskscheduling;
 
+import static java.util.Collections.emptyList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.Arrays;
@@ -31,8 +32,8 @@ public void testLookSchedulingMovingDown() {
     @Test
     public void testLookSchedulingEmptyRequests() {
         LookScheduling lookScheduling = new LookScheduling(50, true, 200);
-        List<Integer> requests = Arrays.asList();
-        List<Integer> expected = Arrays.asList();
+        List<Integer> requests = emptyList();
+        List<Integer> expected = emptyList();
 
         List<Integer> result = lookScheduling.execute(requests);
         assertEquals(expected, result);
diff --git a/src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java
index 1dbcd4893cb9..d1525d9a9c0d 100644
--- a/src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.scheduling.diskscheduling;
 
+import static java.util.Collections.emptyList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.Arrays;
@@ -31,8 +32,8 @@ public void testScanSchedulingMovingDown() {
     @Test
     public void testScanSchedulingEmptyRequests() {
         ScanScheduling scanScheduling = new ScanScheduling(50, true, 200);
-        List<Integer> requests = Arrays.asList();
-        List<Integer> expected = Arrays.asList();
+        List<Integer> requests = emptyList();
+        List<Integer> expected = emptyList();
 
         List<Integer> result = scanScheduling.execute(requests);
         assertEquals(expected, result);
diff --git a/src/test/java/com/thealgorithms/strings/WordLadderTest.java b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
index 0854ad2b0c1f..221953411da7 100644
--- a/src/test/java/com/thealgorithms/strings/WordLadderTest.java
+++ b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.strings;
 
+import static java.util.Collections.emptyList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.Arrays;
@@ -52,7 +53,7 @@ public void testWordLadder2() {
     @Test
     public void testWordLadder3() {
 
-        List<String> wordList3 = Arrays.asList();
+        List<String> wordList3 = emptyList();
         assertEquals(WordLadder.ladderLength("hit", "cog", wordList3), 0);
     }
 

From 539871a33e2a407a1fb3ebdb12d6a15bb18374be Mon Sep 17 00:00:00 2001
From: Mohamed Boukthir <124532428+MohamedBoukthir@users.noreply.github.com>
Date: Sat, 2 Nov 2024 21:44:24 +0100
Subject: [PATCH 0715/1338] Add Fibonacci series to Recursion package (#6079)

---
 .../Recursion/FibonacciSeries.java            | 21 +++++++++++++++
 .../Recursion/FibonacciSeriesTest.java        | 27 +++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/Recursion/FibonacciSeries.java
 create mode 100644 src/test/java/com/thealgorithms/Recursion/FibonacciSeriesTest.java

diff --git a/src/main/java/com/thealgorithms/Recursion/FibonacciSeries.java b/src/main/java/com/thealgorithms/Recursion/FibonacciSeries.java
new file mode 100644
index 000000000000..a89d110b8da3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/Recursion/FibonacciSeries.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.Recursion;
+
+/*
+    The Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones,
+    starting with 0 and 1.
+       NUMBER    0 1 2 3 4 5 6 7  8  9  10 ...
+       FIBONACCI 0 1 1 2 3 5 8 13 21 34 55 ...
+*/
+
+public final class FibonacciSeries {
+    private FibonacciSeries() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+    public static int fibonacci(int n) {
+        if (n <= 1) {
+            return n;
+        } else {
+            return fibonacci(n - 1) + fibonacci(n - 2);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/Recursion/FibonacciSeriesTest.java b/src/test/java/com/thealgorithms/Recursion/FibonacciSeriesTest.java
new file mode 100644
index 000000000000..4e4fc45809ba
--- /dev/null
+++ b/src/test/java/com/thealgorithms/Recursion/FibonacciSeriesTest.java
@@ -0,0 +1,27 @@
+package com.thealgorithms.Recursion;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class FibonacciSeriesTest {
+
+    @Test
+    public void testFibonacci() {
+        assertEquals(0, FibonacciSeries.fibonacci(0));
+        assertEquals(1, FibonacciSeries.fibonacci(1));
+        assertEquals(1, FibonacciSeries.fibonacci(2));
+        assertEquals(2, FibonacciSeries.fibonacci(3));
+        assertEquals(3, FibonacciSeries.fibonacci(4));
+        assertEquals(5, FibonacciSeries.fibonacci(5));
+        assertEquals(8, FibonacciSeries.fibonacci(6));
+        assertEquals(13, FibonacciSeries.fibonacci(7));
+        assertEquals(21, FibonacciSeries.fibonacci(8));
+        assertEquals(34, FibonacciSeries.fibonacci(9));
+        assertEquals(55, FibonacciSeries.fibonacci(10));
+        assertEquals(89, FibonacciSeries.fibonacci(11));
+        assertEquals(144, FibonacciSeries.fibonacci(12));
+        assertEquals(233, FibonacciSeries.fibonacci(13));
+        assertEquals(377, FibonacciSeries.fibonacci(14));
+    }
+}

From 04bfaa82786d367c61ad3be20a72d5502252347e Mon Sep 17 00:00:00 2001
From: Alex Klymenko <alexanderklmn@gmail.com>
Date: Sun, 3 Nov 2024 13:13:10 +0100
Subject: [PATCH 0716/1338] Rename `Recursion` package (#6081)

---
 .../thealgorithms/others/FibbonaciSeries.java | 37 -------------------
 .../FibonacciSeries.java                      |  2 +-
 .../GenerateSubsets.java                      |  2 +-
 .../FibonacciSeriesTest.java                  |  2 +-
 .../GenerateSubsetsTest.java                  |  2 +-
 5 files changed, 4 insertions(+), 41 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/others/FibbonaciSeries.java
 rename src/main/java/com/thealgorithms/{Recursion => recursion}/FibonacciSeries.java (93%)
 rename src/main/java/com/thealgorithms/{Recursion => recursion}/GenerateSubsets.java (96%)
 rename src/test/java/com/thealgorithms/{Recursion => recursion}/FibonacciSeriesTest.java (96%)
 rename src/test/java/com/thealgorithms/{Recursion => recursion}/GenerateSubsetsTest.java (96%)

diff --git a/src/main/java/com/thealgorithms/others/FibbonaciSeries.java b/src/main/java/com/thealgorithms/others/FibbonaciSeries.java
deleted file mode 100644
index a4815296e547..000000000000
--- a/src/main/java/com/thealgorithms/others/FibbonaciSeries.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package com.thealgorithms.others;
-
-import java.util.Scanner;
-
-/**
- * Fibonacci sequence, and characterized by the fact that every number after the
- * first two is the sum of the two preceding ones.
- *
- * <p>
- * Fibonacci sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21,...
- *
- * <p>
- * Source for the explanation: https://en.wikipedia.org/wiki/Fibonacci_number
- *
- * Problem Statement: print all Fibonacci numbers that are smaller than your
- * given input N
- */
-public final class FibbonaciSeries {
-    private FibbonaciSeries() {
-    }
-
-    public static void main(String[] args) {
-        // Get input from the user
-        Scanner scan = new Scanner(System.in);
-        int n = scan.nextInt();
-        int first = 0;
-        int second = 1;
-        scan.close();
-        while (first <= n) {
-            // print first fibo 0 then add second fibo into it while updating second as well
-            System.out.println(first);
-            int next = first + second;
-            first = second;
-            second = next;
-        }
-    }
-}
diff --git a/src/main/java/com/thealgorithms/Recursion/FibonacciSeries.java b/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
similarity index 93%
rename from src/main/java/com/thealgorithms/Recursion/FibonacciSeries.java
rename to src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
index a89d110b8da3..e5f474085367 100644
--- a/src/main/java/com/thealgorithms/Recursion/FibonacciSeries.java
+++ b/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.Recursion;
+package com.thealgorithms.recursion;
 
 /*
     The Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones,
diff --git a/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java b/src/main/java/com/thealgorithms/recursion/GenerateSubsets.java
similarity index 96%
rename from src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java
rename to src/main/java/com/thealgorithms/recursion/GenerateSubsets.java
index 417bf1307790..5a3ff2e88040 100644
--- a/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java
+++ b/src/main/java/com/thealgorithms/recursion/GenerateSubsets.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.Recursion;
+package com.thealgorithms.recursion;
 
 // program to find power set of a string
 
diff --git a/src/test/java/com/thealgorithms/Recursion/FibonacciSeriesTest.java b/src/test/java/com/thealgorithms/recursion/FibonacciSeriesTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/Recursion/FibonacciSeriesTest.java
rename to src/test/java/com/thealgorithms/recursion/FibonacciSeriesTest.java
index 4e4fc45809ba..f8b59f7e9ac6 100644
--- a/src/test/java/com/thealgorithms/Recursion/FibonacciSeriesTest.java
+++ b/src/test/java/com/thealgorithms/recursion/FibonacciSeriesTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.Recursion;
+package com.thealgorithms.recursion;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
diff --git a/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java b/src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java
rename to src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java
index d4bc7e488f80..b92d1406b0a7 100644
--- a/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java
+++ b/src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.Recursion;
+package com.thealgorithms.recursion;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 

From 935a135d97a5833f84abdeb4b6f8be11dee549bf Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 4 Nov 2024 22:34:15 +0100
Subject: [PATCH 0717/1338] Bump org.apache.maven.plugins:maven-surefire-plugin
 from 3.5.1 to 3.5.2 (#6082)

Bumps [org.apache.maven.plugins:maven-surefire-plugin](https://github.com/apache/maven-surefire) from 3.5.1 to 3.5.2.
- [Release notes](https://github.com/apache/maven-surefire/releases)
- [Commits](https://github.com/apache/maven-surefire/compare/surefire-3.5.1...surefire-3.5.2)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-surefire-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 7a0f5f4edcaf..c3d64870d228 100644
--- a/pom.xml
+++ b/pom.xml
@@ -70,7 +70,7 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.5.1</version>
+                <version>3.5.2</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>

From e63ba4be47c2d823813352d67cd85a62fd5de70e Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 8 Nov 2024 00:15:48 +0200
Subject: [PATCH 0718/1338] Bump com.puppycrawl.tools:checkstyle from 10.20.0
 to 10.20.1 (#6085)

---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index c3d64870d228..7e789d3fd696 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.20.0</version>
+                    <version>10.20.1</version>
                     </dependency>
                 </dependencies>
             </plugin>

From b9714537f2006da152b07b11115d77f072eae2b2 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 12 Nov 2024 22:57:20 +0100
Subject: [PATCH 0719/1338] Bump com.github.spotbugs:spotbugs-maven-plugin from
 4.8.6.5 to 4.8.6.6 (#6087)

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.8.6.5 to 4.8.6.6.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.8.6.5...spotbugs-maven-plugin-4.8.6.6)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 7e789d3fd696..d6806a3dee3f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -132,7 +132,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.8.6.5</version>
+                <version>4.8.6.6</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 18b2ab63b8f91313188c6971162e77dfc979d086 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 14 Nov 2024 21:39:39 +0000
Subject: [PATCH 0720/1338] Bump codecov/codecov-action from 4 to 5 in
 /.github/workflows (#6092)

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 4 to 5.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/codecov/codecov-action/compare/v4...v5)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 8178509e7258..b3969075d668 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -17,7 +17,7 @@ jobs:
         if: >-
           github.event_name == 'pull_request' &&
           github.event.pull_request.head.repo.full_name != github.repository
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v5
         with:
           fail_ci_if_error: true
       - name: Upload coverage to codecov (with token)
@@ -25,7 +25,7 @@ jobs:
           github.repository == 'TheAlgorithms/Java' &&
           (github.event_name != 'pull_request' ||
           github.event.pull_request.head.repo.full_name == github.repository)
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v5
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true

From 7ec5d24562c1f473af10057ee8751f468a93da5a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 14 Nov 2024 21:47:44 +0000
Subject: [PATCH 0721/1338] Bump com.mebigfatguy.fb-contrib:fb-contrib from
 7.6.5 to 7.6.8 (#6093)

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.6.5 to 7.6.8.
- [Commits](https://github.com/mebigfatguy/fb-contrib/compare/v7.6.5...v7.6.8)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index d6806a3dee3f..402193e165ef 100644
--- a/pom.xml
+++ b/pom.xml
@@ -140,7 +140,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.5</version>
+                            <version>7.6.8</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

From 1a2aeddec3e2e429c9162aa511e586f452c0d09d Mon Sep 17 00:00:00 2001
From: likespro <likespro.eth@gmail.com>
Date: Tue, 19 Nov 2024 09:09:06 +0200
Subject: [PATCH 0722/1338] Add optimized version of DijkstraAlgorithm (#6088)

---
 .../graphs/DijkstraOptimizedAlgorithm.java    | 66 +++++++++++++++++++
 .../DijkstraOptimizedAlgorithmTest.java       | 64 ++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java
new file mode 100644
index 000000000000..a686b808a970
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java
@@ -0,0 +1,66 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.Arrays;
+import java.util.Set;
+import java.util.TreeSet;
+import org.apache.commons.lang3.tuple.Pair;
+
+/**
+ * Dijkstra's algorithm for finding the shortest path from a single source vertex to all other vertices in a graph.
+ */
+public class DijkstraOptimizedAlgorithm {
+
+    private final int vertexCount;
+
+    /**
+     * Constructs a Dijkstra object with the given number of vertices.
+     *
+     * @param vertexCount The number of vertices in the graph.
+     */
+    public DijkstraOptimizedAlgorithm(int vertexCount) {
+        this.vertexCount = vertexCount;
+    }
+
+    /**
+     * Executes Dijkstra's algorithm on the provided graph to find the shortest paths from the source vertex to all other vertices.
+     *
+     * The graph is represented as an adjacency matrix where {@code graph[i][j]} represents the weight of the edge from vertex {@code i}
+     * to vertex {@code j}. A value of 0 indicates no edge exists between the vertices.
+     *
+     * @param graph The graph represented as an adjacency matrix.
+     * @param source The source vertex.
+     * @return An array where the value at each index {@code i} represents the shortest distance from the source vertex to vertex {@code i}.
+     * @throws IllegalArgumentException if the source vertex is out of range.
+     */
+    public int[] run(int[][] graph, int source) {
+        if (source < 0 || source >= vertexCount) {
+            throw new IllegalArgumentException("Incorrect source");
+        }
+
+        int[] distances = new int[vertexCount];
+        boolean[] processed = new boolean[vertexCount];
+        Set<Pair<Integer, Integer>> unprocessed = new TreeSet<>();
+
+        Arrays.fill(distances, Integer.MAX_VALUE);
+        Arrays.fill(processed, false);
+        distances[source] = 0;
+        unprocessed.add(Pair.of(0, source));
+
+        while (!unprocessed.isEmpty()) {
+            Pair<Integer, Integer> distanceAndU = unprocessed.iterator().next();
+            unprocessed.remove(distanceAndU);
+            int u = distanceAndU.getRight();
+            processed[u] = true;
+
+            for (int v = 0; v < vertexCount; v++) {
+                if (!processed[v] && graph[u][v] != 0 && distances[u] != Integer.MAX_VALUE && distances[u] + graph[u][v] < distances[v]) {
+                    unprocessed.remove(Pair.of(distances[v], v));
+                    distances[v] = distances[u] + graph[u][v];
+                    unprocessed.add(Pair.of(distances[v], v));
+                }
+            }
+        }
+
+        return distances;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java
new file mode 100644
index 000000000000..bf4e2828e069
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java
@@ -0,0 +1,64 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class DijkstraOptimizedAlgorithmTest {
+
+    private DijkstraOptimizedAlgorithm dijkstraOptimizedAlgorithm;
+    private int[][] graph;
+
+    @BeforeEach
+    void setUp() {
+        graph = new int[][] {
+            {0, 4, 0, 0, 0, 0, 0, 8, 0},
+            {4, 0, 8, 0, 0, 0, 0, 11, 0},
+            {0, 8, 0, 7, 0, 4, 0, 0, 2},
+            {0, 0, 7, 0, 9, 14, 0, 0, 0},
+            {0, 0, 0, 9, 0, 10, 0, 0, 0},
+            {0, 0, 4, 14, 10, 0, 2, 0, 0},
+            {0, 0, 0, 0, 0, 2, 0, 1, 6},
+            {8, 11, 0, 0, 0, 0, 1, 0, 7},
+            {0, 0, 2, 0, 0, 0, 6, 7, 0},
+        };
+
+        dijkstraOptimizedAlgorithm = new DijkstraOptimizedAlgorithm(graph.length);
+    }
+
+    @Test
+    void testRunAlgorithm() {
+        int[] expectedDistances = {0, 4, 12, 19, 21, 11, 9, 8, 14};
+        assertArrayEquals(expectedDistances, dijkstraOptimizedAlgorithm.run(graph, 0));
+    }
+
+    @Test
+    void testGraphWithDisconnectedNodes() {
+        int[][] disconnectedGraph = {
+            {0, 3, 0, 0}, {3, 0, 1, 0}, {0, 1, 0, 0}, {0, 0, 0, 0} // Node 3 is disconnected
+        };
+
+        DijkstraOptimizedAlgorithm dijkstraDisconnected = new DijkstraOptimizedAlgorithm(disconnectedGraph.length);
+
+        // Testing from vertex 0
+        int[] expectedDistances = {0, 3, 4, Integer.MAX_VALUE}; // Node 3 is unreachable
+        assertArrayEquals(expectedDistances, dijkstraDisconnected.run(disconnectedGraph, 0));
+    }
+
+    @Test
+    void testSingleVertexGraph() {
+        int[][] singleVertexGraph = {{0}};
+        DijkstraOptimizedAlgorithm dijkstraSingleVertex = new DijkstraOptimizedAlgorithm(1);
+
+        int[] expectedDistances = {0}; // The only vertex's distance to itself is 0
+        assertArrayEquals(expectedDistances, dijkstraSingleVertex.run(singleVertexGraph, 0));
+    }
+
+    @Test
+    void testInvalidSourceVertex() {
+        assertThrows(IllegalArgumentException.class, () -> dijkstraOptimizedAlgorithm.run(graph, -1));
+        assertThrows(IllegalArgumentException.class, () -> dijkstraOptimizedAlgorithm.run(graph, graph.length));
+    }
+}

From 69870f8f55a98d1ae1cd6c8bd74763e6f0e197b2 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 2 Dec 2024 23:57:33 +0100
Subject: [PATCH 0723/1338] Bump gitpod/workspace-java-21 from
 2024-09-11-00-04-27 to 2024-11-26-08-43-19 (#6096)

Bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2024-09-11-00-04-27 to 2024-11-26-08-43-19.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index f426f0921028..4b1885ffa388 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-09-11-00-04-27
+FROM gitpod/workspace-java-21:2024-11-26-08-43-19
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From fff1826df28050629ad84e1c4ac54b029de57435 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 4 Dec 2024 00:40:04 +0100
Subject: [PATCH 0724/1338] Bump com.puppycrawl.tools:checkstyle from 10.20.1
 to 10.20.2 (#6097)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.20.1 to 10.20.2.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.20.1...checkstyle-10.20.2)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 402193e165ef..b0554afac2ad 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.20.1</version>
+                    <version>10.20.2</version>
                     </dependency>
                 </dependencies>
             </plugin>

From ebd7a3748c37798bb5d1b32e8ec79b3c9d712e55 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 12 Dec 2024 23:31:33 +0100
Subject: [PATCH 0725/1338] Bump com.puppycrawl.tools:checkstyle from 10.20.2
 to 10.21.0 (#6098)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.20.2 to 10.21.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.20.2...checkstyle-10.21.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b0554afac2ad..438e0bab33bd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.20.2</version>
+                    <version>10.21.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 9dfd99906139b4b04042c77cee0117f64d412a60 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 16 Dec 2024 18:05:41 +0000
Subject: [PATCH 0726/1338] Bump org.junit:junit-bom from 5.11.3 to 5.11.4
 (#6101)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.11.3 to 5.11.4.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.3...r5.11.4)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 438e0bab33bd..78a49920fea9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.11.3</version>
+                <version>5.11.4</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 2792c83bfb7364b0d0871aeeab793e5e6d9b9ebb Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 16 Dec 2024 18:09:39 +0000
Subject: [PATCH 0727/1338] Bump com.mebigfatguy.fb-contrib:fb-contrib from
 7.6.8 to 7.6.9 (#6100)

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.6.8 to 7.6.9.
- [Commits](https://github.com/mebigfatguy/fb-contrib/commits)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 78a49920fea9..6419fc640541 100644
--- a/pom.xml
+++ b/pom.xml
@@ -140,7 +140,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.8</version>
+                            <version>7.6.9</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

From 1e9cb9687d37316df445fa2fb12d7545c1606948 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 16 Dec 2024 18:13:37 +0000
Subject: [PATCH 0728/1338] Bump org.junit.jupiter:junit-jupiter from 5.11.3 to
 5.11.4 (#6103)

Bumps [org.junit.jupiter:junit-jupiter](https://github.com/junit-team/junit5) from 5.11.3 to 5.11.4.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.3...r5.11.4)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 6419fc640541..71c537a51f63 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.11.3</version>
+            <version>5.11.4</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 13b5d6297e0fb24b001935969f745819e63d660e Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 16 Dec 2024 18:17:41 +0000
Subject: [PATCH 0729/1338] Bump org.junit.jupiter:junit-jupiter-api from
 5.11.3 to 5.11.4 (#6102)

Bumps [org.junit.jupiter:junit-jupiter-api](https://github.com/junit-team/junit5) from 5.11.3 to 5.11.4.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.3...r5.11.4)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter-api
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 71c537a51f63..48ad8a73be27 100644
--- a/pom.xml
+++ b/pom.xml
@@ -51,7 +51,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>5.11.3</version>
+            <version>5.11.4</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From d65745816e7a6bf70e219bf217e8ab72dcf2c383 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 19 Dec 2024 23:35:24 +0100
Subject: [PATCH 0730/1338] Bump org.assertj:assertj-core from 3.26.3 to 3.27.0
 (#6106)

Bumps [org.assertj:assertj-core](https://github.com/assertj/assertj) from 3.26.3 to 3.27.0.
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](https://github.com/assertj/assertj/compare/assertj-build-3.26.3...assertj-build-3.27.0)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 48ad8a73be27..ec5f4f2b1785 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.26.3</assertj.version>
+        <assertj.version>3.27.0</assertj.version>
     </properties>
 
     <dependencyManagement>

From d102fa77dc90172be6cf7eddd02af7ee3fb5da2a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 19 Dec 2024 22:38:53 +0000
Subject: [PATCH 0731/1338] Bump org.apache.commons:commons-collections4 from
 4.5.0-M2 to 4.5.0-M3 (#6107)

Bumps org.apache.commons:commons-collections4 from 4.5.0-M2 to 4.5.0-M3.

---
updated-dependencies:
- dependency-name: org.apache.commons:commons-collections4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index ec5f4f2b1785..256a0ab296d8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -62,7 +62,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-collections4</artifactId>
-            <version>4.5.0-M2</version>
+            <version>4.5.0-M3</version>
         </dependency>
     </dependencies>
 

From 2fff5790450c1b58a329d1ec576c6bc155b503ea Mon Sep 17 00:00:00 2001
From: Nguyen Tan Phat <52371943+nguyentanphat8694@users.noreply.github.com>
Date: Sat, 21 Dec 2024 20:02:58 +0700
Subject: [PATCH 0732/1338] Add unit test for EditDistance (#6108)

---
 .../dynamicprogramming/EditDistanceTest.java  | 89 +++++++++++++++++++
 1 file changed, 89 insertions(+)

diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java
index 267be9b056de..737e8d1d0918 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java
@@ -1,7 +1,9 @@
 package com.thealgorithms.dynamicprogramming;
 
+import static org.junit.jupiter.api.Assertions.assertAll;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
 
@@ -12,4 +14,91 @@ public class EditDistanceTest {
     void testMinDistance(String str1, String str2, int expected) {
         assertEquals(expected, EditDistance.minDistance(str1, str2));
     }
+
+    @Test
+    public void testEditDistanceBothEmptyStrings() {
+        assertEquals(0, EditDistance.editDistance("", ""));
+    }
+
+    @Test
+    public void testEditDistanceOneEmptyString() {
+        assertEquals(5, EditDistance.editDistance("", "hello"));
+        assertEquals(7, EditDistance.editDistance("worldly", ""));
+    }
+
+    @Test
+    public void testEditDistanceOneEmptyStringMemoization() {
+        int[][] storage = new int[1][6];
+        assertAll("String assertions",
+            ()
+                -> assertEquals(5, EditDistance.editDistance("", "hello", storage)),
+            () -> assertEquals(0, storage[0][0]), () -> assertEquals(0, storage[0][1]), () -> assertEquals(0, storage[0][2]), () -> assertEquals(0, storage[0][3]), () -> assertEquals(0, storage[0][4]), () -> assertEquals(5, storage[0][5]));
+    }
+
+    @Test
+    public void testEditDistanceEqualStrings() {
+        assertEquals(0, EditDistance.editDistance("test", "test"));
+        assertEquals(0, EditDistance.editDistance("abc", "abc"));
+    }
+
+    @Test
+    public void testEditDistanceEqualStringsMemoization() {
+        int[][] storage = new int[4][4];
+        assertAll("String assertions",
+            ()
+                -> assertEquals(0, EditDistance.editDistance("abc", "abc", storage)),
+            ()
+                -> assertEquals(0, storage[0][0]),
+            ()
+                -> assertEquals(0, storage[0][1]),
+            ()
+                -> assertEquals(0, storage[0][2]),
+            ()
+                -> assertEquals(0, storage[0][3]),
+            ()
+                -> assertEquals(0, storage[1][0]),
+            ()
+                -> assertEquals(0, storage[1][1]),
+            ()
+                -> assertEquals(0, storage[1][2]),
+            ()
+                -> assertEquals(0, storage[1][3]),
+            ()
+                -> assertEquals(0, storage[2][0]),
+            () -> assertEquals(0, storage[2][1]), () -> assertEquals(0, storage[2][2]), () -> assertEquals(0, storage[2][3]), () -> assertEquals(0, storage[3][0]), () -> assertEquals(0, storage[3][1]), () -> assertEquals(0, storage[3][2]), () -> assertEquals(0, storage[3][3]));
+    }
+
+    @Test
+    public void testEditDistanceOneCharacterDifference() {
+        assertEquals(1, EditDistance.editDistance("cat", "bat"));
+        assertEquals(1, EditDistance.editDistance("cat", "cats"));
+        assertEquals(1, EditDistance.editDistance("cats", "cat"));
+    }
+
+    @Test
+    public void testEditDistanceOneCharacterDifferenceMemoization() {
+        int[][] storage = new int[3][3];
+        assertAll("All assertions",
+            ()
+                -> assertEquals(1, EditDistance.editDistance("at", "it", storage)),
+            ()
+                -> assertEquals(0, storage[0][0]),
+            ()
+                -> assertEquals(1, storage[0][1]),
+            () -> assertEquals(2, storage[0][2]), () -> assertEquals(1, storage[1][0]), () -> assertEquals(0, storage[1][1]), () -> assertEquals(1, storage[1][2]), () -> assertEquals(2, storage[2][0]), () -> assertEquals(1, storage[2][1]), () -> assertEquals(1, storage[2][2]));
+    }
+
+    @Test
+    public void testEditDistanceGeneralCases() {
+        assertEquals(3, EditDistance.editDistance("kitten", "sitting"));
+        assertEquals(2, EditDistance.editDistance("flaw", "lawn"));
+        assertEquals(5, EditDistance.editDistance("intention", "execution"));
+    }
+
+    @Test
+    public void testEditDistanceGeneralCasesMemoization() {
+        int[][] storage = new int[7][8];
+        assertEquals(3, EditDistance.editDistance("kitten", "sitting", storage));
+        assertAll("All assertions", () -> assertEquals(0, storage[0][0]), () -> assertEquals(3, storage[6][7]));
+    }
 }

From 6a60458398fb327e9f2a8d41c12ca884fc00ff17 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sun, 29 Dec 2024 19:59:25 +0000
Subject: [PATCH 0733/1338] Bump com.puppycrawl.tools:checkstyle from 10.21.0
 to 10.21.1 (#6114)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.21.0 to 10.21.1.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.21.0...checkstyle-10.21.1)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 256a0ab296d8..142eb079b5ae 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.21.0</version>
+                    <version>10.21.1</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 2da56d6ee4833068227fe92b637236620cf70bbb Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 2 Jan 2025 00:35:00 +0200
Subject: [PATCH 0734/1338] Bump org.assertj:assertj-core from 3.27.0 to 3.27.1
 (#6115)

---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 142eb079b5ae..6535b4f39bf3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.27.0</assertj.version>
+        <assertj.version>3.27.1</assertj.version>
     </properties>
 
     <dependencyManagement>

From 14db275c2b7abb0091587231bd823e8e00cbd32f Mon Sep 17 00:00:00 2001
From: Stanislav Belogolov <shisoik@gmail.com>
Date: Wed, 1 Jan 2025 23:43:00 +0100
Subject: [PATCH 0735/1338] Improve Vampire Number (#6110)

---
 .../thealgorithms/maths/VampireNumber.java    | 74 ++++++-------------
 .../maths/VampireNumberTest.java              | 32 ++++++++
 2 files changed, 54 insertions(+), 52 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/VampireNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/VampireNumber.java b/src/main/java/com/thealgorithms/maths/VampireNumber.java
index 8820f8a23f70..45bb9a587778 100644
--- a/src/main/java/com/thealgorithms/maths/VampireNumber.java
+++ b/src/main/java/com/thealgorithms/maths/VampireNumber.java
@@ -1,78 +1,48 @@
 package com.thealgorithms.maths;
 
 import java.util.ArrayList;
-import java.util.Collections;
 
 /**
- * n number theory, a vampire number (or true vampire number) is a composite
+ * In number theory, a vampire number (or true vampire number) is a composite
  * natural number with an even number of digits, that can be factored into two
  * natural numbers each with half as many digits as the original number and not
  * both with trailing zeroes, where the two factors contain precisely all the
  * digits of the original number, in any order, counting multiplicity. The first
- * vampire number is 1260 = 21 × 60. *
+ * vampire number is 1260 = 21 × 60.
  *
- * <p>
- * link: https://en.wikipedia.org/wiki/Vampire_number *
- *
- * <p>
+ * @see <a href='https://en.wikipedia.org/wiki/Vampire_number'>Vampire number on Wikipedia</a>
  */
 public final class VampireNumber {
+    // Forbid instantiation.
     private VampireNumber() {
     }
 
-    public static void main(String[] args) {
-        test(10, 1000);
-    }
-
-    static void test(int startValue, int stopValue) {
-        int countofRes = 1;
-        StringBuilder res = new StringBuilder();
-
-        for (int i = startValue; i <= stopValue; i++) {
-            for (int j = i; j <= stopValue; j++) {
-                // System.out.println(i+ " "+ j);
-                if (isVampireNumber(i, j, true)) {
-                    countofRes++;
-                    res.append("").append(countofRes).append(": = ( ").append(i).append(",").append(j).append(" = ").append(i * j).append(")").append("\n");
-                }
-            }
-        }
-        System.out.println(res);
-    }
-
-    static boolean isVampireNumber(int a, int b, boolean noPseudoVamireNumbers) {
-        // this is for pseudoVampireNumbers  pseudovampire number need not be of length n/2 digits
-        // for example 126 = 6 x 21
-        if (noPseudoVamireNumbers) {
-            if (a * 10 <= b || b * 10 <= a) {
-                return false;
-            }
+    static boolean isVampireNumber(int a, int b, boolean ignorePseudoVampireNumbers) {
+        // Pseudo vampire numbers don't have to be of n/2 digits. E.g., 126 = 6 x 21 is such a number.
+        if (ignorePseudoVampireNumbers && String.valueOf(a).length() != String.valueOf(b).length()) {
+            return false;
         }
 
-        String mulDigits = splitIntoDigits(a * b, 0);
-        String faktorDigits = splitIntoDigits(a, b);
+        String mulDigits = splitIntoSortedDigits(a * b);
+        String factorDigits = splitIntoSortedDigits(a, b);
 
-        return mulDigits.equals(faktorDigits);
+        return mulDigits.equals(factorDigits);
     }
 
-    // methode to Split the numbers to Digits
-    static String splitIntoDigits(int num, int num2) {
-        StringBuilder res = new StringBuilder();
-
+    // Method to split a pair of numbers to digits and sort them in the ascending order.
+    static String splitIntoSortedDigits(int... nums) {
+        // Collect all digits in a list.
         ArrayList<Integer> digits = new ArrayList<>();
-        while (num > 0) {
-            digits.add(num % 10);
-            num /= 10;
-        }
-        while (num2 > 0) {
-            digits.add(num2 % 10);
-            num2 /= 10;
-        }
-        Collections.sort(digits);
-        for (int i : digits) {
-            res.append(i);
+        for (int num : nums) {
+            while (num > 0) {
+                digits.add(num % 10);
+                num /= 10;
+            }
         }
 
+        // Sort all digits and convert to String.
+        StringBuilder res = new StringBuilder();
+        digits.stream().sorted().forEach(res::append);
         return res.toString();
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/VampireNumberTest.java b/src/test/java/com/thealgorithms/maths/VampireNumberTest.java
new file mode 100644
index 000000000000..6f331f1252cd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/VampireNumberTest.java
@@ -0,0 +1,32 @@
+package com.thealgorithms.maths;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+class VampireNumberTest {
+    @Test
+    void areVampireNumbers() {
+        Assertions.assertTrue(VampireNumber.isVampireNumber(15, 93, true));
+        Assertions.assertTrue(VampireNumber.isVampireNumber(135, 801, true));
+        Assertions.assertTrue(VampireNumber.isVampireNumber(201, 600, true));
+    }
+
+    @Test
+    void arePseudoVampireNumbers() {
+        Assertions.assertTrue(VampireNumber.isVampireNumber(150, 93, false));
+        Assertions.assertTrue(VampireNumber.isVampireNumber(546, 84, false));
+        Assertions.assertTrue(VampireNumber.isVampireNumber(641, 65, false));
+    }
+
+    @Test
+    void areNotVampireNumbers() {
+        Assertions.assertFalse(VampireNumber.isVampireNumber(51, 39, false));
+        Assertions.assertFalse(VampireNumber.isVampireNumber(51, 39, true));
+    }
+
+    @Test
+    void testSplitIntoSortedDigits() {
+        Assertions.assertEquals("123", VampireNumber.splitIntoSortedDigits(321));
+        Assertions.assertEquals("02234", VampireNumber.splitIntoSortedDigits(20, 324));
+    }
+}

From 7c5351e11e620cb9d674140356c3aa0981838da6 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 2 Jan 2025 22:34:13 +0100
Subject: [PATCH 0736/1338] Bump org.mockito:mockito-core from 5.14.2 to 5.15.2
 (#6116)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.14.2 to 5.15.2.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.14.2...v5.15.2)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 6535b4f39bf3..b52e125a91e0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -43,7 +43,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.14.2</version>
+            <version>5.15.2</version>
             <scope>test</scope>
         </dependency>
 

From 5ab6356090c17cddd953c801eac4abb6ef48c9f1 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 6 Jan 2025 21:34:03 +0000
Subject: [PATCH 0737/1338] Bump org.assertj:assertj-core from 3.27.1 to 3.27.2
 (#6117)

Bumps [org.assertj:assertj-core](https://github.com/assertj/assertj) from 3.27.1 to 3.27.2.
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](https://github.com/assertj/assertj/compare/assertj-build-3.27.1...assertj-build-3.27.2)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b52e125a91e0..3fc2c89d339f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.27.1</assertj.version>
+        <assertj.version>3.27.2</assertj.version>
     </properties>
 
     <dependencyManagement>

From a9633c00007f3e2037d74f358ec917b142e3c630 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 10 Jan 2025 19:50:09 +0100
Subject: [PATCH 0738/1338] style: include `ICAST_IDIV_CAST_TO_DOUBLE` (#6121)

---
 spotbugs-exclude.xml                                      | 3 ---
 src/main/java/com/thealgorithms/maths/Average.java        | 4 ++--
 src/main/java/com/thealgorithms/others/KochSnowflake.java | 2 +-
 3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 14bc5dfe9439..11f89248018f 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -41,9 +41,6 @@
     <Match>
         <Bug pattern="INT_BAD_REM_BY_1" />
     </Match>
-    <Match>
-        <Bug pattern="ICAST_IDIV_CAST_TO_DOUBLE" />
-    </Match>
     <Match>
         <Bug pattern="FE_FLOATING_POINT_EQUALITY" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/maths/Average.java b/src/main/java/com/thealgorithms/maths/Average.java
index 6b9c20162da1..a550a7f6504d 100644
--- a/src/main/java/com/thealgorithms/maths/Average.java
+++ b/src/main/java/com/thealgorithms/maths/Average.java
@@ -37,7 +37,7 @@ public static double average(double[] numbers) {
      * @return the average of the given numbers
      * @throws IllegalArgumentException if the input array is {@code null} or empty
      */
-    public static double average(int[] numbers) {
+    public static long average(int[] numbers) {
         if (numbers == null || numbers.length == 0) {
             throw new IllegalArgumentException("Numbers array cannot be empty or null");
         }
@@ -45,6 +45,6 @@ public static double average(int[] numbers) {
         for (int number : numbers) {
             sum += number;
         }
-        return (double) (sum / numbers.length);
+        return sum / numbers.length;
     }
 }
diff --git a/src/main/java/com/thealgorithms/others/KochSnowflake.java b/src/main/java/com/thealgorithms/others/KochSnowflake.java
index 46b8edb1f177..10986aabec4f 100644
--- a/src/main/java/com/thealgorithms/others/KochSnowflake.java
+++ b/src/main/java/com/thealgorithms/others/KochSnowflake.java
@@ -105,7 +105,7 @@ public static BufferedImage getKochSnowflake(int imageWidth, int steps) {
         double offsetX = imageWidth / 10.;
         double offsetY = imageWidth / 3.7;
         Vector2 vector1 = new Vector2(offsetX, offsetY);
-        Vector2 vector2 = new Vector2(imageWidth / 2, Math.sin(Math.PI / 3) * imageWidth * 0.8 + offsetY);
+        Vector2 vector2 = new Vector2(imageWidth / 2.0, Math.sin(Math.PI / 3.0) * imageWidth * 0.8 + offsetY);
         Vector2 vector3 = new Vector2(imageWidth - offsetX, offsetY);
         ArrayList<Vector2> initialVectors = new ArrayList<Vector2>();
         initialVectors.add(vector1);

From 1e6ed97fcf96d15556466e371096b0159ffe63af Mon Sep 17 00:00:00 2001
From: varada610 <varada.gurjar@gmail.com>
Date: Fri, 10 Jan 2025 23:17:40 -0800
Subject: [PATCH 0739/1338] Refactor files to be in correctly nested packages
 (#6120)

---
 pmd-exclude.properties                        |   1 -
 .../{misc => matrix}/InverseOfMatrix.java     |   2 +-
 .../{misc => matrix}/MatrixTranspose.java     |   2 +-
 .../{misc => matrix}/MedianOfMatrix.java      |   2 +-
 .../{misc => matrix}/MirrorOfMatrix.java      |   2 +-
 .../PrintAMatrixInSpiralOrder.java            | 124 +++++++++---------
 .../RotateMatrixBy90Degrees.java              |   2 +-
 .../matrixexponentiation/Fibonacci.java       |   6 +-
 .../{misc => matrix}/InverseOfMatrixTest.java |   3 +-
 .../{misc => matrix}/MatrixTransposeTest.java |   2 +-
 .../{misc => matrix}/MedianOfMatrixTest.java  |   2 +-
 .../{misc => matrix}/MirrorOfMatrixTest.java  |   2 +-
 .../TestPrintMatrixInSpiralOrder.java         |   2 +-
 13 files changed, 75 insertions(+), 77 deletions(-)
 rename src/main/java/com/thealgorithms/{misc => matrix}/InverseOfMatrix.java (98%)
 rename src/main/java/com/thealgorithms/{misc => matrix}/MatrixTranspose.java (97%)
 rename src/main/java/com/thealgorithms/{misc => matrix}/MedianOfMatrix.java (95%)
 rename src/main/java/com/thealgorithms/{misc => matrix}/MirrorOfMatrix.java (98%)
 rename src/main/java/com/thealgorithms/{others => matrix}/PrintAMatrixInSpiralOrder.java (94%)
 rename src/main/java/com/thealgorithms/{others => matrix}/RotateMatrixBy90Degrees.java (98%)
 rename src/main/java/com/thealgorithms/{ => matrix}/matrixexponentiation/Fibonacci.java (93%)
 rename src/test/java/com/thealgorithms/{misc => matrix}/InverseOfMatrixTest.java (96%)
 rename src/test/java/com/thealgorithms/{misc => matrix}/MatrixTransposeTest.java (98%)
 rename src/test/java/com/thealgorithms/{misc => matrix}/MedianOfMatrixTest.java (96%)
 rename src/test/java/com/thealgorithms/{misc => matrix}/MirrorOfMatrixTest.java (98%)
 rename src/test/java/com/thealgorithms/{others => matrix}/TestPrintMatrixInSpiralOrder.java (96%)

diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index f6ee88196962..5bf31455e190 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -55,7 +55,6 @@ com.thealgorithms.maths.SumOfArithmeticSeries=UselessParentheses
 com.thealgorithms.maths.TrinomialTriangle=UselessParentheses
 com.thealgorithms.maths.VampireNumber=CollapsibleIfStatements
 com.thealgorithms.maths.Volume=UselessParentheses
-com.thealgorithms.matrixexponentiation.Fibonacci=UnnecessaryFullyQualifiedName
 com.thealgorithms.misc.Sparsity=UselessParentheses
 com.thealgorithms.misc.ThreeSumProblem=UselessParentheses
 com.thealgorithms.misc.WordBoggle=UselessParentheses
diff --git a/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java b/src/main/java/com/thealgorithms/matrix/InverseOfMatrix.java
similarity index 98%
rename from src/main/java/com/thealgorithms/misc/InverseOfMatrix.java
rename to src/main/java/com/thealgorithms/matrix/InverseOfMatrix.java
index 706feab0c69d..13e795a91297 100644
--- a/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java
+++ b/src/main/java/com/thealgorithms/matrix/InverseOfMatrix.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.matrix;
 
 /**
  * This class provides methods to compute the inverse of a square matrix
diff --git a/src/main/java/com/thealgorithms/misc/MatrixTranspose.java b/src/main/java/com/thealgorithms/matrix/MatrixTranspose.java
similarity index 97%
rename from src/main/java/com/thealgorithms/misc/MatrixTranspose.java
rename to src/main/java/com/thealgorithms/matrix/MatrixTranspose.java
index 743682780b01..f91ebc10b8a9 100644
--- a/src/main/java/com/thealgorithms/misc/MatrixTranspose.java
+++ b/src/main/java/com/thealgorithms/matrix/MatrixTranspose.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.matrix;
 
 /**
  *
diff --git a/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java b/src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java
similarity index 95%
rename from src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
rename to src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java
index edeedbbee540..c710c60a2d2a 100644
--- a/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java
+++ b/src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.matrix;
 
 import java.util.ArrayList;
 import java.util.Collections;
diff --git a/src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java b/src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java
similarity index 98%
rename from src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java
rename to src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java
index 89dfce3fe049..b24fcba75619 100644
--- a/src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java
+++ b/src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.matrix;
 
 // Problem Statement
 /*
diff --git a/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java b/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java
similarity index 94%
rename from src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java
rename to src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java
index ddc37a916cbf..2e735222b7a6 100644
--- a/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java
+++ b/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java
@@ -1,62 +1,62 @@
-package com.thealgorithms.others;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class PrintAMatrixInSpiralOrder {
-    /**
-     * Search a key in row and column wise sorted matrix
-     *
-     * @param matrix matrix to be searched
-     * @param row    number of rows matrix has
-     * @param col    number of columns matrix has
-     * @author Sadiul Hakim : https://github.com/sadiul-hakim
-     */
-
-    public List<Integer> print(int[][] matrix, int row, int col) {
-
-        // r traverses matrix row wise from first
-        int r = 0;
-        // c traverses matrix column wise from first
-        int c = 0;
-        int i;
-
-        List<Integer> result = new ArrayList<>();
-
-        while (r < row && c < col) {
-            // print first row of matrix
-            for (i = c; i < col; i++) {
-                result.add(matrix[r][i]);
-            }
-
-            // increase r by one because first row printed
-            r++;
-
-            // print last column
-            for (i = r; i < row; i++) {
-                result.add(matrix[i][col - 1]);
-            }
-
-            // decrease col by one because last column has been printed
-            col--;
-
-            // print rows from last except printed elements
-            if (r < row) {
-                for (i = col - 1; i >= c; i--) {
-                    result.add(matrix[row - 1][i]);
-                }
-
-                row--;
-            }
-
-            // print columns from first except printed elements
-            if (c < col) {
-                for (i = row - 1; i >= r; i--) {
-                    result.add(matrix[i][c]);
-                }
-                c++;
-            }
-        }
-        return result;
-    }
-}
+package com.thealgorithms.matrix;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class PrintAMatrixInSpiralOrder {
+    /**
+     * Search a key in row and column wise sorted matrix
+     *
+     * @param matrix matrix to be searched
+     * @param row    number of rows matrix has
+     * @param col    number of columns matrix has
+     * @author Sadiul Hakim : https://github.com/sadiul-hakim
+     */
+
+    public List<Integer> print(int[][] matrix, int row, int col) {
+
+        // r traverses matrix row wise from first
+        int r = 0;
+        // c traverses matrix column wise from first
+        int c = 0;
+        int i;
+
+        List<Integer> result = new ArrayList<>();
+
+        while (r < row && c < col) {
+            // print first row of matrix
+            for (i = c; i < col; i++) {
+                result.add(matrix[r][i]);
+            }
+
+            // increase r by one because first row printed
+            r++;
+
+            // print last column
+            for (i = r; i < row; i++) {
+                result.add(matrix[i][col - 1]);
+            }
+
+            // decrease col by one because last column has been printed
+            col--;
+
+            // print rows from last except printed elements
+            if (r < row) {
+                for (i = col - 1; i >= c; i--) {
+                    result.add(matrix[row - 1][i]);
+                }
+
+                row--;
+            }
+
+            // print columns from first except printed elements
+            if (c < col) {
+                for (i = row - 1; i >= r; i--) {
+                    result.add(matrix[i][c]);
+                }
+                c++;
+            }
+        }
+        return result;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java b/src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java
similarity index 98%
rename from src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
rename to src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java
index 6ad0ef024342..9a7f255282ac 100644
--- a/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java
+++ b/src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.matrix;
 
 import java.util.Scanner;
 /**
diff --git a/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java b/src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java
similarity index 93%
rename from src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java
rename to src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java
index afd34933047a..9c9f97b93ea4 100644
--- a/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java
+++ b/src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.matrixexponentiation;
+package com.thealgorithms.matrix.matrixexponentiation;
 
 import java.util.Scanner;
 
@@ -55,14 +55,14 @@ private static int[][] matrixMultiplication(int[][] matrix1, int[][] matrix2) {
      */
     public static int[][] fib(int n) {
         if (n == 0) {
-            return Fibonacci.IDENTITY_MATRIX;
+            return IDENTITY_MATRIX;
         } else {
             int[][] cachedResult = fib(n / 2);
             int[][] matrixExpResult = matrixMultiplication(cachedResult, cachedResult);
             if (n % 2 == 0) {
                 return matrixExpResult;
             } else {
-                return matrixMultiplication(Fibonacci.FIB_MATRIX, matrixExpResult);
+                return matrixMultiplication(FIB_MATRIX, matrixExpResult);
             }
         }
     }
diff --git a/src/test/java/com/thealgorithms/misc/InverseOfMatrixTest.java b/src/test/java/com/thealgorithms/matrix/InverseOfMatrixTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/misc/InverseOfMatrixTest.java
rename to src/test/java/com/thealgorithms/matrix/InverseOfMatrixTest.java
index 2f20de444315..930fb377cd32 100644
--- a/src/test/java/com/thealgorithms/misc/InverseOfMatrixTest.java
+++ b/src/test/java/com/thealgorithms/matrix/InverseOfMatrixTest.java
@@ -1,5 +1,4 @@
-package com.thealgorithms.misc;
-
+package com.thealgorithms.matrix;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import java.util.stream.Stream;
diff --git a/src/test/java/com/thealgorithms/misc/MatrixTransposeTest.java b/src/test/java/com/thealgorithms/matrix/MatrixTransposeTest.java
similarity index 98%
rename from src/test/java/com/thealgorithms/misc/MatrixTransposeTest.java
rename to src/test/java/com/thealgorithms/matrix/MatrixTransposeTest.java
index cf668807b819..0457f31418cf 100644
--- a/src/test/java/com/thealgorithms/misc/MatrixTransposeTest.java
+++ b/src/test/java/com/thealgorithms/matrix/MatrixTransposeTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.matrix;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
diff --git a/src/test/java/com/thealgorithms/misc/MedianOfMatrixTest.java b/src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/misc/MedianOfMatrixTest.java
rename to src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java
index 19bc66857ae6..db66bb2d187b 100644
--- a/src/test/java/com/thealgorithms/misc/MedianOfMatrixTest.java
+++ b/src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.matrix;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
diff --git a/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java b/src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java
similarity index 98%
rename from src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java
rename to src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java
index 0da0cf0f804a..2d68e1faaa17 100644
--- a/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java
+++ b/src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.matrix;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
diff --git a/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java b/src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java
similarity index 96%
rename from src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java
rename to src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java
index 986e72ea45b5..bb415a5861a8 100644
--- a/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java
+++ b/src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.matrix;
 
 import static org.junit.jupiter.api.Assertions.assertIterableEquals;
 

From 08c0f4ac2ddfa48e1a00e2dd9c7a350ecb7d4d23 Mon Sep 17 00:00:00 2001
From: Rully <rully@ajaib.co.id>
Date: Sun, 12 Jan 2025 18:13:01 +0700
Subject: [PATCH 0740/1338] improve zig-zag-pattern (#6128)

---
 .../strings/zigZagPattern/ZigZagPattern.java  | 49 +++++++++----------
 .../zigZagPattern/ZigZagPatternTest.java      |  6 ++-
 2 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java b/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java
index 3f33fc17b9b0..ad7835bdbb97 100644
--- a/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java
+++ b/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java
@@ -1,41 +1,38 @@
 package com.thealgorithms.strings.zigZagPattern;
 
 final class ZigZagPattern {
+
     private ZigZagPattern() {
     }
 
+    /**
+     * Encodes a given string into a zig-zag pattern.
+     *
+     * @param s       the input string to be encoded
+     * @param numRows the number of rows in the zigzag pattern
+     * @return the encoded string in zigzag pattern format
+     */
     public static String encode(String s, int numRows) {
         if (numRows < 2 || s.length() < numRows) {
             return s;
         }
-        int start = 0;
-        int index = 0;
-        int height = 1;
-        int depth = numRows;
-        char[] zigZagedArray = new char[s.length()];
-        while (depth != 0) {
-            int pointer = start;
-            int heightSpace = 2 + ((height - 2) * 2);
-            int depthSpace = 2 + ((depth - 2) * 2);
-            boolean bool = true;
-            while (pointer < s.length()) {
-                zigZagedArray[index++] = s.charAt(pointer);
-                if (heightSpace == 0) {
-                    pointer += depthSpace;
-                } else if (depthSpace == 0) {
-                    pointer += heightSpace;
-                } else if (bool) {
-                    pointer += depthSpace;
-                    bool = false;
-                } else {
-                    pointer += heightSpace;
-                    bool = true;
+
+        StringBuilder result = new StringBuilder(s.length());
+        int cycleLength = 2 * numRows - 2;
+
+        for (int row = 0; row < numRows; row++) {
+            for (int j = row; j < s.length(); j += cycleLength) {
+                result.append(s.charAt(j));
+
+                if (row > 0 && row < numRows - 1) {
+                    int diagonal = j + cycleLength - 2 * row;
+                    if (diagonal < s.length()) {
+                        result.append(s.charAt(diagonal));
+                    }
                 }
             }
-            height++;
-            depth--;
-            start++;
         }
-        return new String(zigZagedArray);
+
+        return result.toString();
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java b/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java
index 518bfab80f08..2cbbfe3d2dd8 100644
--- a/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java
+++ b/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java
@@ -6,10 +6,14 @@
 public class ZigZagPatternTest {
 
     @Test
-    public void palindrome() {
+    public void testZigZagPattern() {
         String input1 = "HelloWorldFromJava";
         String input2 = "javaIsAProgrammingLanguage";
         Assertions.assertEquals(ZigZagPattern.encode(input1, 4), "HooeWrrmalolFJvlda");
         Assertions.assertEquals(ZigZagPattern.encode(input2, 4), "jAaLgasPrmgaaevIrgmnnuaoig");
+        // Edge cases
+        Assertions.assertEquals("ABC", ZigZagPattern.encode("ABC", 1)); // Single row
+        Assertions.assertEquals("A", ZigZagPattern.encode("A", 2)); // numRows > length of string
+        Assertions.assertEquals("", ZigZagPattern.encode("", 3)); // Empty string
     }
 }

From bd785dea4dadc2b2967d174cf3afebe88a699fb8 Mon Sep 17 00:00:00 2001
From: "p@ren" <83308376+paren-thesis@users.noreply.github.com>
Date: Sun, 12 Jan 2025 11:29:27 +0000
Subject: [PATCH 0741/1338] Refactor and enhance the 'Upper' class (#6118)

---
 .../java/com/thealgorithms/strings/Upper.java    | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/Upper.java b/src/main/java/com/thealgorithms/strings/Upper.java
index fa9a408416ea..5e248cb6ee39 100644
--- a/src/main/java/com/thealgorithms/strings/Upper.java
+++ b/src/main/java/com/thealgorithms/strings/Upper.java
@@ -21,15 +21,19 @@ public static void main(String[] args) {
      * @return the {@code String}, converted to uppercase.
      */
     public static String toUpperCase(String s) {
-        if (s == null || s.isEmpty()) {
+        if (s == null) {
+            throw new IllegalArgumentException("Input string connot be null");
+        }
+        if (s.isEmpty()) {
             return s;
         }
-        char[] values = s.toCharArray();
-        for (int i = 0; i < values.length; ++i) {
-            if (Character.isLetter(values[i]) && Character.isLowerCase(values[i])) {
-                values[i] = Character.toUpperCase(values[i]);
+        StringBuilder result = new StringBuilder(s);
+        for (int i = 0; i < result.length(); ++i) {
+            char currentChar = result.charAt(i);
+            if (Character.isLetter(currentChar) && Character.isLowerCase(currentChar)) {
+                result.setCharAt(i, Character.toUpperCase(currentChar));
             }
         }
-        return new String(values);
+        return result.toString();
     }
 }

From 779381f902821ea8fa8dc641b01d513e1a050b99 Mon Sep 17 00:00:00 2001
From: Patient_Pace_Coder
 <104113247+Patient-Pace-Coder@users.noreply.github.com>
Date: Mon, 13 Jan 2025 13:34:08 +0530
Subject: [PATCH 0742/1338] Update Armstrong (#6131)

---
 src/main/java/com/thealgorithms/maths/Armstrong.java | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Armstrong.java b/src/main/java/com/thealgorithms/maths/Armstrong.java
index ff4ae027a0b7..9a7a014ec99f 100644
--- a/src/main/java/com/thealgorithms/maths/Armstrong.java
+++ b/src/main/java/com/thealgorithms/maths/Armstrong.java
@@ -10,6 +10,7 @@
  * An Armstrong number is often called a Narcissistic number.
  *
  * @author satyabarghav
+ * @modifier rahul katteda - (13/01/2025) - [updated the logic for getting total number of digits]
  */
 public class Armstrong {
 
@@ -20,14 +21,16 @@ public class Armstrong {
      * @return {@code true} if the given number is an Armstrong number, {@code false} otherwise
      */
     public boolean isArmstrong(int number) {
+        if (number < 0) {
+            return false; // Negative numbers cannot be Armstrong numbers
+        }
         long sum = 0;
-        String temp = Integer.toString(number); // Convert the given number to a string
-        int power = temp.length(); // Extract the length of the number (number of digits)
+        int totalDigits = (int) Math.log10(number) + 1; // get the length of the number (number of digits)
         long originalNumber = number;
 
         while (originalNumber > 0) {
             long digit = originalNumber % 10;
-            sum += (long) Math.pow(digit, power); // The digit raised to the power of the number of digits and added to the sum.
+            sum += (long) Math.pow(digit, totalDigits); // The digit raised to the power of total number of digits and added to the sum.
             originalNumber /= 10;
         }
 

From 39122a9ac79d4c7094c6741293780bb804d7623f Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 13 Jan 2025 17:56:43 +0100
Subject: [PATCH 0743/1338] style: include
 `PCOA_PARTIALLY_CONSTRUCTED_OBJECT_ACCESS` (#6133)

---
 spotbugs-exclude.xml                          |  3 --
 .../scheduling/SJFScheduling.java             | 28 +++++++++----------
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 11f89248018f..d3eff458ea45 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -114,9 +114,6 @@
     <Match>
         <Bug pattern="BL_BURYING_LOGIC" />
     </Match>
-    <Match>
-        <Bug pattern="PCOA_PARTIALLY_CONSTRUCTED_OBJECT_ACCESS" />
-    </Match>
     <Match>
         <Bug pattern="UTWR_USE_TRY_WITH_RESOURCES" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java b/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
index 6d105003e68f..cbbc65a3afc5 100644
--- a/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
@@ -14,6 +14,18 @@ public class SJFScheduling {
     protected ArrayList<ProcessDetails> processes;
     protected ArrayList<String> schedule;
 
+    private static void sortProcessesByArrivalTime(List<ProcessDetails> processes) {
+        for (int i = 0; i < processes.size(); i++) {
+            for (int j = i + 1; j < processes.size() - 1; j++) {
+                if (processes.get(j).getArrivalTime() > processes.get(j + 1).getArrivalTime()) {
+                    final var temp = processes.get(j);
+                    processes.set(j, processes.get(j + 1));
+                    processes.set(j + 1, temp);
+                }
+            }
+        }
+    }
+
     /**
      * a simple constructor
      * @param processes a list of processes the user wants to schedule
@@ -22,22 +34,10 @@ public class SJFScheduling {
     SJFScheduling(final ArrayList<ProcessDetails> processes) {
         this.processes = processes;
         schedule = new ArrayList<>();
-        sortByArrivalTime();
+        sortProcessesByArrivalTime(this.processes);
     }
     protected void sortByArrivalTime() {
-        int size = processes.size();
-        int i;
-        int j;
-        ProcessDetails temp;
-        for (i = 0; i < size; i++) {
-            for (j = i + 1; j < size - 1; j++) {
-                if (processes.get(j).getArrivalTime() > processes.get(j + 1).getArrivalTime()) {
-                    temp = processes.get(j);
-                    processes.set(j, processes.get(j + 1));
-                    processes.set(j + 1, temp);
-                }
-            }
-        }
+        sortProcessesByArrivalTime(processes);
     }
 
     /**

From 754bf6c5f8f55b758bdee2667f6cadf4f0ab659f Mon Sep 17 00:00:00 2001
From: BILLSARAN <121570181+BILLSARAN@users.noreply.github.com>
Date: Mon, 13 Jan 2025 23:37:58 +0200
Subject: [PATCH 0744/1338] Add Goldbach's Conjecture algorithm (#6127)

---
 .../maths/GoldbachConjecture.java             | 30 +++++++++++++++++++
 .../maths/GoldbachConjectureTest.java         | 29 ++++++++++++++++++
 2 files changed, 59 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/GoldbachConjecture.java
 create mode 100644 src/test/java/com/thealgorithms/maths/GoldbachConjectureTest.java

diff --git a/src/main/java/com/thealgorithms/maths/GoldbachConjecture.java b/src/main/java/com/thealgorithms/maths/GoldbachConjecture.java
new file mode 100644
index 000000000000..52391bc100d8
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/GoldbachConjecture.java
@@ -0,0 +1,30 @@
+package com.thealgorithms.maths;
+
+import static com.thealgorithms.maths.PrimeCheck.isPrime;
+
+/**
+ * This is a representation of the unsolved problem of Goldbach's Projection, according to which every
+ * even natural number greater than 2 can be written as the sum of 2 prime numbers
+ * More info: https://en.wikipedia.org/wiki/Goldbach%27s_conjecture
+ * @author Vasilis Sarantidis (https://github.com/BILLSARAN)
+ */
+
+public final class GoldbachConjecture {
+    private GoldbachConjecture() {
+    }
+    public record Result(int number1, int number2) {
+    }
+
+    public static Result getPrimeSum(int number) {
+        if (number <= 2 || number % 2 != 0) {
+            throw new IllegalArgumentException("Number must be even and greater than 2.");
+        }
+
+        for (int i = 0; i <= number / 2; i++) {
+            if (isPrime(i) && isPrime(number - i)) {
+                return new Result(i, number - i);
+            }
+        }
+        throw new IllegalStateException("No valid prime sum found."); // Should not occur
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/GoldbachConjectureTest.java b/src/test/java/com/thealgorithms/maths/GoldbachConjectureTest.java
new file mode 100644
index 000000000000..84c5824d26ae
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/GoldbachConjectureTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.maths;
+
+import static com.thealgorithms.maths.GoldbachConjecture.getPrimeSum;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class GoldbachConjectureTest {
+    @Test
+    void testValidEvenNumbers() {
+        assertEquals(new GoldbachConjecture.Result(3, 7), getPrimeSum(10)); // 10 = 3 + 7
+        assertEquals(new GoldbachConjecture.Result(5, 7), getPrimeSum(12)); // 12 = 5 + 7
+        assertEquals(new GoldbachConjecture.Result(3, 11), getPrimeSum(14)); // 14 = 3 + 11
+        assertEquals(new GoldbachConjecture.Result(5, 13), getPrimeSum(18)); // 18 = 5 + 13
+    }
+    @Test
+    void testInvalidOddNumbers() {
+        assertThrows(IllegalArgumentException.class, () -> getPrimeSum(7));
+        assertThrows(IllegalArgumentException.class, () -> getPrimeSum(15));
+    }
+    @Test
+    void testLesserThanTwo() {
+        assertThrows(IllegalArgumentException.class, () -> getPrimeSum(1));
+        assertThrows(IllegalArgumentException.class, () -> getPrimeSum(2));
+        assertThrows(IllegalArgumentException.class, () -> getPrimeSum(-5));
+        assertThrows(IllegalArgumentException.class, () -> getPrimeSum(-26));
+    }
+}

From 466ff0b4c27437993994909b229300111ef357be Mon Sep 17 00:00:00 2001
From: Prathamesh Zingade
 <101877850+ZingadePrathamesh@users.noreply.github.com>
Date: Thu, 16 Jan 2025 13:16:57 +0530
Subject: [PATCH 0745/1338] Add convertion of numbers into their word
 representation (#6137)

---
 DIRECTORY.md                                  |  48 +++++----
 .../conversions/NumberToWords.java            | 100 ++++++++++++++++++
 .../conversions/NumberToWordsTest.java        |  60 +++++++++++
 3 files changed, 190 insertions(+), 18 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/conversions/NumberToWords.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/NumberToWordsTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 01e031b58581..4fa1392a3c17 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -5,6 +5,7 @@
       * com
         * thealgorithms
           * audiofilters
+            * [EMAFilter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/audiofilters/EMAFilter.java)
             * [IIRFilter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/audiofilters/IIRFilter.java)
           * backtracking
             * [AllPathsFromSourceToTarget](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java)
@@ -107,6 +108,7 @@
             * [IPConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IPConverter.java)
             * [IPv6Converter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IPv6Converter.java)
             * [MorseCodeConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/MorseCodeConverter.java)
+            * [NumberToWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/NumberToWords.java)
             * [OctalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToBinary.java)
             * [OctalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java)
             * [OctalToHexadecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java)
@@ -147,6 +149,7 @@
               * [ConnectedComponent](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java)
               * [Cycles](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java)
               * [DijkstraAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java)
+              * [DijkstraOptimizedAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java)
               * [EdmondsBlossomAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java)
               * [FloydWarshall](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java)
               * [FordFulkerson](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java)
@@ -404,6 +407,7 @@
             * [GCD](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/GCD.java)
             * [GCDRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/GCDRecursion.java)
             * [GenericRoot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/GenericRoot.java)
+            * [GoldbachConjecture](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/GoldbachConjecture.java)
             * [HarshadNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/HarshadNumber.java)
             * [HeronsFormula](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/HeronsFormula.java)
             * [JosephusProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/JosephusProblem.java)
@@ -470,21 +474,24 @@
             * [VampireNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/VampireNumber.java)
             * [VectorCrossProduct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java)
             * [Volume](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Volume.java)
-          * matrixexponentiation
-            * [Fibonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrixexponentiation/Fibonacci.java)
+          * matrix
+            * [InverseOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/InverseOfMatrix.java)
+            * matrixexponentiation
+              * [Fibonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java)
+            * [MatrixTranspose](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MatrixTranspose.java)
+            * [MedianOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java)
+            * [MirrorOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java)
+            * [PrintAMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java)
+            * [RotateMatrixBy90Degrees](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java)
           * misc
             * [ColorContrastRatio](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java)
-            * [InverseOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/InverseOfMatrix.java)
             * [MapReduce](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MapReduce.java)
-            * [MatrixTranspose](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MatrixTranspose.java)
-            * [MedianOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfMatrix.java)
             * [MedianOfRunningArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java)
             * [MedianOfRunningArrayByte](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayByte.java)
             * [MedianOfRunningArrayDouble](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayDouble.java)
             * [MedianOfRunningArrayFloat](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayFloat.java)
             * [MedianOfRunningArrayInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayInteger.java)
             * [MedianOfRunningArrayLong](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayLong.java)
-            * [MirrorOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MirrorOfMatrix.java)
             * [PalindromePrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromePrime.java)
             * [PalindromeSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java)
             * [RangeInSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java)
@@ -508,7 +515,6 @@
             * [CRCAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CRCAlgorithm.java)
             * [Damm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Damm.java)
             * [Dijkstra](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Dijkstra.java)
-            * [FibbonaciSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/FibbonaciSeries.java)
             * [FloydTriangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/FloydTriangle.java)
             * [GaussLegendre](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/GaussLegendre.java)
             * [HappyNumbersSeq](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java)
@@ -529,18 +535,17 @@
             * [PageRank](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PageRank.java)
             * [PasswordGen](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PasswordGen.java)
             * [PerlinNoise](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PerlinNoise.java)
-            * [PrintAMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java)
             * [QueueUsingTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java)
             * [RemoveDuplicateFromString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java)
             * [ReverseStackUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
-            * [RotateMatrixBy90Degrees](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java)
             * [SkylineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SkylineProblem.java)
             * [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Sudoku.java)
             * [TowerOfHanoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TowerOfHanoi.java)
             * [TwoPointers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TwoPointers.java)
             * [Verhoeff](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Verhoeff.java)
-          * Recursion
-            * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java)
+          * recursion
+            * [FibonacciSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java)
+            * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/recursion/GenerateSubsets.java)
           * scheduling
             * [AgingScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/AgingScheduling.java)
             * diskscheduling
@@ -718,6 +723,7 @@
       * com
         * thealgorithms
           * audiofilters
+            * [EMAFilterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/audiofilters/EMAFilterTest.java)
             * [IIRFilterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/audiofilters/IIRFilterTest.java)
           * backtracking
             * [AllPathsFromSourceToTargetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/AllPathsFromSourceToTargetTest.java)
@@ -814,6 +820,7 @@
             * [IPConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IPConverterTest.java)
             * [IPv6ConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IPv6ConverterTest.java)
             * [MorseCodeConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/MorseCodeConverterTest.java)
+            * [NumberToWordsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/NumberToWordsTest.java)
             * [OctalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java)
             * [OctalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java)
             * [OctalToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
@@ -849,6 +856,7 @@
               * [BipartiteGraphDFSTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java)
               * [BoruvkaAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
               * [DijkstraAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java)
+              * [DijkstraOptimizedAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java)
               * [EdmondsBlossomAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java)
               * [FloydWarshallTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FloydWarshallTest.java)
               * [FordFulkersonTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java)
@@ -1070,6 +1078,7 @@
             * [GCDRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GCDRecursionTest.java)
             * [GCDTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GCDTest.java)
             * [GenericRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GenericRootTest.java)
+            * [GoldbachConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GoldbachConjectureTest.java)
             * [HarshadNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java)
             * [HeronsFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java)
             * [JosephusProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/JosephusProblemTest.java)
@@ -1126,15 +1135,18 @@
             * [TestArmstrong](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TestArmstrong.java)
             * [TwinPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TwinPrimeTest.java)
             * [UniformNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/UniformNumbersTest.java)
+            * [VampireNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/VampireNumberTest.java)
             * [VolumeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/VolumeTest.java)
+          * matrix
+            * [InverseOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/InverseOfMatrixTest.java)
+            * [MatrixTransposeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MatrixTransposeTest.java)
+            * [MedianOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java)
+            * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java)
+            * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java)
           * misc
             * [ColorContrastRatioTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java)
-            * [InverseOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/InverseOfMatrixTest.java)
             * [MapReduceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MapReduceTest.java)
-            * [MatrixTransposeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MatrixTransposeTest.java)
-            * [MedianOfMatrixtest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfMatrixtest.java)
             * [MedianOfRunningArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java)
-            * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MirrorOfMatrixTest.java)
             * [PalindromePrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java)
             * [PalindromeSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java)
             * [RangeInSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java)
@@ -1171,12 +1183,12 @@
             * [ReverseStackUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
             * [SkylineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
             * [SudokuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SudokuTest.java)
-            * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
             * [TowerOfHanoiTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TowerOfHanoiTest.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
-          * Recursion
-            * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/Recursion/GenerateSubsetsTest.java)
+          * recursion
+            * [FibonacciSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/recursion/FibonacciSeriesTest.java)
+            * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java)
           * scheduling
             * [AgingSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/AgingSchedulingTest.java)
             * diskscheduling
diff --git a/src/main/java/com/thealgorithms/conversions/NumberToWords.java b/src/main/java/com/thealgorithms/conversions/NumberToWords.java
new file mode 100644
index 000000000000..e39c5b2dea86
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/NumberToWords.java
@@ -0,0 +1,100 @@
+package com.thealgorithms.conversions;
+
+import java.math.BigDecimal;
+
+/**
+ A Java-based utility for converting numeric values into their English word
+ representations. Whether you need to convert a small number, a large number
+ with millions and billions, or even a number with decimal places, this utility
+ has you covered.
+ *
+ */
+public final class NumberToWords {
+
+    private NumberToWords() {
+    }
+
+    private static final String[] UNITS = {"", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"};
+
+    private static final String[] TENS = {"", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"};
+
+    private static final String[] POWERS = {"", "Thousand", "Million", "Billion", "Trillion"};
+
+    private static final String ZERO = "Zero";
+    private static final String POINT = " Point";
+    private static final String NEGATIVE = "Negative ";
+
+    public static String convert(BigDecimal number) {
+        if (number == null) {
+            return "Invalid Input";
+        }
+
+        // Check for negative sign
+        boolean isNegative = number.signum() < 0;
+
+        // Split the number into whole and fractional parts
+        BigDecimal[] parts = number.abs().divideAndRemainder(BigDecimal.ONE);
+        BigDecimal wholePart = parts[0]; // Keep whole part as BigDecimal
+        String fractionalPartStr = parts[1].compareTo(BigDecimal.ZERO) > 0 ? parts[1].toPlainString().substring(2) : ""; // Get fractional part only if it exists
+
+        // Convert whole part to words
+        StringBuilder result = new StringBuilder();
+        if (isNegative) {
+            result.append(NEGATIVE);
+        }
+        result.append(convertWholeNumberToWords(wholePart));
+
+        // Convert fractional part to words
+        if (!fractionalPartStr.isEmpty()) {
+            result.append(POINT);
+            for (char digit : fractionalPartStr.toCharArray()) {
+                int digitValue = Character.getNumericValue(digit);
+                result.append(" ").append(digitValue == 0 ? ZERO : UNITS[digitValue]);
+            }
+        }
+
+        return result.toString().trim();
+    }
+
+    private static String convertWholeNumberToWords(BigDecimal number) {
+        if (number.compareTo(BigDecimal.ZERO) == 0) {
+            return ZERO;
+        }
+
+        StringBuilder words = new StringBuilder();
+        int power = 0;
+
+        while (number.compareTo(BigDecimal.ZERO) > 0) {
+            // Get the last three digits
+            BigDecimal[] divisionResult = number.divideAndRemainder(BigDecimal.valueOf(1000));
+            int chunk = divisionResult[1].intValue();
+
+            if (chunk > 0) {
+                String chunkWords = convertChunk(chunk);
+                if (power > 0) {
+                    words.insert(0, POWERS[power] + " ");
+                }
+                words.insert(0, chunkWords + " ");
+            }
+
+            number = divisionResult[0]; // Continue with the remaining part
+            power++;
+        }
+
+        return words.toString().trim();
+    }
+
+    private static String convertChunk(int number) {
+        String chunkWords;
+
+        if (number < 20) {
+            chunkWords = UNITS[number];
+        } else if (number < 100) {
+            chunkWords = TENS[number / 10] + (number % 10 > 0 ? " " + UNITS[number % 10] : "");
+        } else {
+            chunkWords = UNITS[number / 100] + " Hundred" + (number % 100 > 0 ? " " + convertChunk(number % 100) : "");
+        }
+
+        return chunkWords;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/NumberToWordsTest.java b/src/test/java/com/thealgorithms/conversions/NumberToWordsTest.java
new file mode 100644
index 000000000000..7b264678daa4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/NumberToWordsTest.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.math.BigDecimal;
+import org.junit.jupiter.api.Test;
+
+public class NumberToWordsTest {
+
+    @Test
+    void testNullInput() {
+        assertEquals("Invalid Input", NumberToWords.convert(null), "Null input should return 'Invalid Input'");
+    }
+
+    @Test
+    void testZeroInput() {
+        assertEquals("Zero", NumberToWords.convert(BigDecimal.ZERO), "Zero input should return 'Zero'");
+    }
+
+    @Test
+    void testPositiveWholeNumbers() {
+        assertEquals("One", NumberToWords.convert(BigDecimal.ONE), "1 should convert to 'One'");
+        assertEquals("One Thousand", NumberToWords.convert(new BigDecimal("1000")), "1000 should convert to 'One Thousand'");
+        assertEquals("One Million", NumberToWords.convert(new BigDecimal("1000000")), "1000000 should convert to 'One Million'");
+    }
+
+    @Test
+    void testNegativeWholeNumbers() {
+        assertEquals("Negative One", NumberToWords.convert(new BigDecimal("-1")), "-1 should convert to 'Negative One'");
+        assertEquals("Negative One Thousand", NumberToWords.convert(new BigDecimal("-1000")), "-1000 should convert to 'Negative One Thousand'");
+    }
+
+    @Test
+    void testFractionalNumbers() {
+        assertEquals("Zero Point One Two Three", NumberToWords.convert(new BigDecimal("0.123")), "0.123 should convert to 'Zero Point One Two Three'");
+        assertEquals("Negative Zero Point Four Five Six", NumberToWords.convert(new BigDecimal("-0.456")), "-0.456 should convert to 'Negative Zero Point Four Five Six'");
+    }
+
+    @Test
+    void testLargeNumbers() {
+        assertEquals("Nine Hundred Ninety Nine Million Nine Hundred Ninety Nine Thousand Nine Hundred Ninety Nine", NumberToWords.convert(new BigDecimal("999999999")), "999999999 should convert correctly");
+        assertEquals("One Trillion", NumberToWords.convert(new BigDecimal("1000000000000")), "1000000000000 should convert to 'One Trillion'");
+    }
+
+    @Test
+    void testNegativeLargeNumbers() {
+        assertEquals("Negative Nine Trillion Eight Hundred Seventy Six Billion Five Hundred Forty Three Million Two Hundred Ten Thousand Nine Hundred Eighty Seven", NumberToWords.convert(new BigDecimal("-9876543210987")), "-9876543210987 should convert correctly");
+    }
+
+    @Test
+    void testFloatingPointPrecision() {
+        assertEquals("One Million Point Zero Zero One", NumberToWords.convert(new BigDecimal("1000000.001")), "1000000.001 should convert to 'One Million Point Zero Zero One'");
+    }
+
+    @Test
+    void testEdgeCases() {
+        assertEquals("Zero", NumberToWords.convert(new BigDecimal("-0.0")), "-0.0 should convert to 'Zero'");
+        assertEquals("Zero Point Zero Zero Zero Zero Zero Zero One", NumberToWords.convert(new BigDecimal("1E-7")), "1E-7 should convert to 'Zero Point Zero Zero Zero Zero Zero Zero One'");
+    }
+}

From 5454e2ff626547eaac3edad1d1459f6bf5ca7e7f Mon Sep 17 00:00:00 2001
From: Sahil Kumar Valecha
 <106372522+sahilkumarvalecha@users.noreply.github.com>
Date: Sat, 18 Jan 2025 22:34:34 +0500
Subject: [PATCH 0746/1338] Add DarkSort Algorithm (#6141)

---
 .../com/thealgorithms/sorts/DarkSort.java     | 59 +++++++++++++++
 .../com/thealgorithms/sorts/DarkSortTest.java | 74 +++++++++++++++++++
 2 files changed, 133 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/DarkSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/DarkSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/DarkSort.java b/src/main/java/com/thealgorithms/sorts/DarkSort.java
new file mode 100644
index 000000000000..4887d7d124ba
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/DarkSort.java
@@ -0,0 +1,59 @@
+package com.thealgorithms.sorts;
+
+/**
+ * Dark Sort algorithm implementation.
+ *
+ * Dark Sort uses a temporary array to count occurrences of elements and
+ * reconstructs the sorted array based on the counts.
+ */
+class DarkSort {
+
+    /**
+     * Sorts the array using the Dark Sort algorithm.
+     *
+     * @param unsorted the array to be sorted
+     * @return sorted array
+     */
+    public Integer[] sort(Integer[] unsorted) {
+        if (unsorted == null || unsorted.length <= 1) {
+            return unsorted;
+        }
+
+        int max = findMax(unsorted); // Find the maximum value in the array
+
+        // Create a temporary array for counting occurrences
+        int[] temp = new int[max + 1];
+
+        // Count occurrences of each element
+        for (int value : unsorted) {
+            temp[value]++;
+        }
+
+        // Reconstruct the sorted array
+        int index = 0;
+        for (int i = 0; i < temp.length; i++) {
+            while (temp[i] > 0) {
+                unsorted[index++] = i;
+                temp[i]--;
+            }
+        }
+
+        return unsorted;
+    }
+
+    /**
+     * Helper method to find the maximum value in an array.
+     *
+     * @param arr the array
+     * @return the maximum value
+     */
+    private int findMax(Integer[] arr) {
+        int max = arr[0];
+        for (int value : arr) {
+            if (value > max) {
+                max = value;
+            }
+        }
+        return max;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/DarkSortTest.java b/src/test/java/com/thealgorithms/sorts/DarkSortTest.java
new file mode 100644
index 000000000000..1df077e2ad74
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/DarkSortTest.java
@@ -0,0 +1,74 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+class DarkSortTest {
+
+    @Test
+    void testSortWithIntegers() {
+        Integer[] unsorted = {5, 3, 8, 6, 2, 7, 4, 1};
+        Integer[] expected = {1, 2, 3, 4, 5, 6, 7, 8};
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertArrayEquals(expected, sorted);
+    }
+
+    @Test
+    void testEmptyArray() {
+        Integer[] unsorted = {};
+        Integer[] expected = {};
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertArrayEquals(expected, sorted);
+    }
+
+    @Test
+    void testSingleElementArray() {
+        Integer[] unsorted = {42};
+        Integer[] expected = {42};
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertArrayEquals(expected, sorted);
+    }
+
+    @Test
+    void testAlreadySortedArray() {
+        Integer[] unsorted = {1, 2, 3, 4, 5};
+        Integer[] expected = {1, 2, 3, 4, 5};
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertArrayEquals(expected, sorted);
+    }
+
+    @Test
+    void testDuplicateElementsArray() {
+        Integer[] unsorted = {4, 2, 7, 2, 1, 4};
+        Integer[] expected = {1, 2, 2, 4, 4, 7};
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertArrayEquals(expected, sorted);
+    }
+
+    @Test
+    void testNullArray() {
+        Integer[] unsorted = null;
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertNull(sorted, "Sorting a null array should return null");
+    }
+}

From 30d0c064a7723f2c1e0dc485eefd31d747e1497a Mon Sep 17 00:00:00 2001
From: Muhammad Rizwan <88393515+rizwan-ilyas@users.noreply.github.com>
Date: Sun, 19 Jan 2025 00:51:56 +0500
Subject: [PATCH 0747/1338] Fix absolute max bug (#6144)

---
 src/main/java/com/thealgorithms/maths/AbsoluteMax.java    | 2 +-
 .../java/com/thealgorithms/maths/AbsoluteMaxTest.java     | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/maths/AbsoluteMax.java b/src/main/java/com/thealgorithms/maths/AbsoluteMax.java
index d0c3db3790a3..c32a408b6609 100644
--- a/src/main/java/com/thealgorithms/maths/AbsoluteMax.java
+++ b/src/main/java/com/thealgorithms/maths/AbsoluteMax.java
@@ -17,7 +17,7 @@ public static int getMaxValue(int... numbers) {
         }
         int absMax = numbers[0];
         for (int i = 1; i < numbers.length; i++) {
-            if (Math.abs(numbers[i]) > Math.abs(absMax)) {
+            if (Math.abs(numbers[i]) > Math.abs(absMax) || (Math.abs(numbers[i]) == Math.abs(absMax) && numbers[i] > absMax)) {
                 absMax = numbers[i];
             }
         }
diff --git a/src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java b/src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java
index 70d2f64bc541..33461fbbc088 100644
--- a/src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java
+++ b/src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java
@@ -19,4 +19,12 @@ void testGetMaxValue() {
     void testGetMaxValueWithNoArguments() {
         assertThrows(IllegalArgumentException.class, AbsoluteMax::getMaxValue);
     }
+
+    @Test
+    void testGetMaxValueWithSameAbsoluteValues() {
+        assertEquals(5, AbsoluteMax.getMaxValue(-5, 5));
+        assertEquals(5, AbsoluteMax.getMaxValue(5, -5));
+        assertEquals(12, AbsoluteMax.getMaxValue(-12, 9, 3, 12, 1));
+        assertEquals(12, AbsoluteMax.getMaxValue(12, 9, 3, -12, 1));
+    }
 }

From 0e0539ea6c9d40189edb19bb462fdd7f72057170 Mon Sep 17 00:00:00 2001
From: Muhammad Rizwan <88393515+rizwan-ilyas@users.noreply.github.com>
Date: Sun, 19 Jan 2025 21:50:43 +0500
Subject: [PATCH 0748/1338] Fix AbsoluteMin bug for equal absolute values
 (#6145)

* fix-absolute-max-bug

* clang-format for added junit

* fix-absolute-min-bug
---
 src/main/java/com/thealgorithms/maths/AbsoluteMin.java    | 2 +-
 .../java/com/thealgorithms/maths/AbsoluteMinTest.java     | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/AbsoluteMin.java b/src/main/java/com/thealgorithms/maths/AbsoluteMin.java
index 1ffe6d2e81bc..1b9575a330dd 100644
--- a/src/main/java/com/thealgorithms/maths/AbsoluteMin.java
+++ b/src/main/java/com/thealgorithms/maths/AbsoluteMin.java
@@ -19,7 +19,7 @@ public static int getMinValue(int... numbers) {
 
         var absMinWrapper = new Object() { int value = numbers[0]; };
 
-        Arrays.stream(numbers).skip(1).filter(number -> Math.abs(number) < Math.abs(absMinWrapper.value)).forEach(number -> absMinWrapper.value = number);
+        Arrays.stream(numbers).skip(1).filter(number -> Math.abs(number) <= Math.abs(absMinWrapper.value)).forEach(number -> absMinWrapper.value = Math.min(absMinWrapper.value, number));
 
         return absMinWrapper.value;
     }
diff --git a/src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java b/src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java
index 4b676ca634f7..dfca757fd877 100644
--- a/src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java
+++ b/src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java
@@ -15,7 +15,13 @@ void testGetMinValue() {
 
     @Test
     void testGetMinValueWithNoArguments() {
-        Exception exception = assertThrows(IllegalArgumentException.class, () -> AbsoluteMin.getMinValue());
+        Exception exception = assertThrows(IllegalArgumentException.class, AbsoluteMin::getMinValue);
         assertEquals("Numbers array cannot be empty", exception.getMessage());
     }
+
+    @Test
+    void testGetMinValueWithSameAbsoluteValues() {
+        assertEquals(-5, AbsoluteMin.getMinValue(-5, 5));
+        assertEquals(-5, AbsoluteMin.getMinValue(5, -5));
+    }
 }

From 364f66025a08494c172687ecb5081ef0605b50d4 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 20 Jan 2025 21:58:53 +0000
Subject: [PATCH 0749/1338] Bump org.assertj:assertj-core from 3.27.2 to 3.27.3
 (#6146)

Bumps [org.assertj:assertj-core](https://github.com/assertj/assertj) from 3.27.2 to 3.27.3.
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](https://github.com/assertj/assertj/compare/assertj-build-3.27.2...assertj-build-3.27.3)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 3fc2c89d339f..d246f378ba71 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.27.2</assertj.version>
+        <assertj.version>3.27.3</assertj.version>
     </properties>
 
     <dependencyManagement>

From f9efd382d1d5e0fa0ddb54c17283fc079b957386 Mon Sep 17 00:00:00 2001
From: Syed Rizvi <mohsinrizvi.dgk@gmail.com>
Date: Sun, 26 Jan 2025 17:28:49 +0000
Subject: [PATCH 0750/1338] Fix: Replaced removeLast() with
 remove(current.size() - 1)  (#6152)

Fix: Replaced removeLast() with remove(current.size() - 1) for compatibility with ArrayList
---
 .../java/com/thealgorithms/backtracking/ArrayCombination.java   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
index 6569896bd1b7..f8cd0c40c20e 100644
--- a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
+++ b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
@@ -48,7 +48,7 @@ private static void combine(List<List<Integer>> combinations, List<Integer> curr
         for (int i = start; i < n; i++) {
             current.add(i);
             combine(combinations, current, i + 1, n, k);
-            current.removeLast(); // Backtrack
+            current.remove(current.size() - 1); // Backtrack
         }
     }
 }

From 4ef06822caaea334ab4493d7e0b087d3c74c0acd Mon Sep 17 00:00:00 2001
From: varada610 <varada.gurjar@gmail.com>
Date: Mon, 27 Jan 2025 03:10:41 -0800
Subject: [PATCH 0751/1338] Create package prime, matrix and games (#6139)

---
 .../maths/GoldbachConjecture.java             |  2 +-
 .../{ => Prime}/LiouvilleLambdaFunction.java  |  4 +-
 .../MillerRabinPrimalityCheck.java            |  2 +-
 .../maths/{ => Prime}/MobiusFunction.java     |  4 +-
 .../maths/{ => Prime}/PrimeCheck.java         |  2 +-
 .../maths/{ => Prime}/PrimeFactorization.java |  2 +-
 .../maths/{ => Prime}/SquareFreeInteger.java  |  2 +-
 .../com/thealgorithms/maths/TwinPrime.java    |  2 +
 .../{maths => matrix}/MatrixRank.java         | 45 +--------------
 .../thealgorithms/matrix/MirrorOfMatrix.java  | 35 +++---------
 .../matrixexponentiation/Fibonacci.java       | 56 ++++---------------
 .../{maths => matrix/utils}/MatrixUtil.java   | 56 ++++++++++++++++++-
 .../{others => puzzlesandgames}/Sudoku.java   |  2 +-
 .../TowerOfHanoi.java                         |  2 +-
 .../{misc => puzzlesandgames}/WordBoggle.java |  4 +-
 .../maths/SquareFreeIntegerTest.java          |  1 +
 .../LiouvilleLambdaFunctionTest.java          |  3 +-
 .../MillerRabinPrimalityCheckTest.java        |  3 +-
 .../maths/{ => prime}/MobiusFunctionTest.java |  3 +-
 .../maths/{ => prime}/PrimeCheckTest.java     |  3 +-
 .../{ => prime}/PrimeFactorizationTest.java   |  3 +-
 .../{maths => matrix}/MatrixRankTest.java     |  2 +-
 .../{maths => matrix}/MatrixUtilTest.java     |  3 +-
 .../matrix/MirrorOfMatrixTest.java            | 36 ++++++------
 .../SudokuTest.java                           |  2 +-
 .../TowerOfHanoiTest.java                     |  2 +-
 .../WordBoggleTest.java                       |  2 +-
 27 files changed, 123 insertions(+), 160 deletions(-)
 rename src/main/java/com/thealgorithms/maths/{ => Prime}/LiouvilleLambdaFunction.java (93%)
 rename src/main/java/com/thealgorithms/maths/{ => Prime}/MillerRabinPrimalityCheck.java (98%)
 rename src/main/java/com/thealgorithms/maths/{ => Prime}/MobiusFunction.java (96%)
 rename src/main/java/com/thealgorithms/maths/{ => Prime}/PrimeCheck.java (98%)
 rename src/main/java/com/thealgorithms/maths/{ => Prime}/PrimeFactorization.java (95%)
 rename src/main/java/com/thealgorithms/maths/{ => Prime}/SquareFreeInteger.java (97%)
 rename src/main/java/com/thealgorithms/{maths => matrix}/MatrixRank.java (77%)
 rename src/main/java/com/thealgorithms/{maths => matrix/utils}/MatrixUtil.java (62%)
 rename src/main/java/com/thealgorithms/{others => puzzlesandgames}/Sudoku.java (99%)
 rename src/main/java/com/thealgorithms/{others => puzzlesandgames}/TowerOfHanoi.java (98%)
 rename src/main/java/com/thealgorithms/{misc => puzzlesandgames}/WordBoggle.java (98%)
 rename src/test/java/com/thealgorithms/maths/{ => prime}/LiouvilleLambdaFunctionTest.java (94%)
 rename src/test/java/com/thealgorithms/maths/{ => prime}/MillerRabinPrimalityCheckTest.java (92%)
 rename src/test/java/com/thealgorithms/maths/{ => prime}/MobiusFunctionTest.java (96%)
 rename src/test/java/com/thealgorithms/maths/{ => prime}/PrimeCheckTest.java (89%)
 rename src/test/java/com/thealgorithms/maths/{ => prime}/PrimeFactorizationTest.java (93%)
 rename src/test/java/com/thealgorithms/{maths => matrix}/MatrixRankTest.java (98%)
 rename src/test/java/com/thealgorithms/{maths => matrix}/MatrixUtilTest.java (96%)
 rename src/test/java/com/thealgorithms/{others => puzzlesandgames}/SudokuTest.java (97%)
 rename src/test/java/com/thealgorithms/{others => puzzlesandgames}/TowerOfHanoiTest.java (97%)
 rename src/test/java/com/thealgorithms/{misc => puzzlesandgames}/WordBoggleTest.java (98%)

diff --git a/src/main/java/com/thealgorithms/maths/GoldbachConjecture.java b/src/main/java/com/thealgorithms/maths/GoldbachConjecture.java
index 52391bc100d8..4e962722ba88 100644
--- a/src/main/java/com/thealgorithms/maths/GoldbachConjecture.java
+++ b/src/main/java/com/thealgorithms/maths/GoldbachConjecture.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import static com.thealgorithms.maths.PrimeCheck.isPrime;
+import static com.thealgorithms.maths.Prime.PrimeCheck.isPrime;
 
 /**
  * This is a representation of the unsolved problem of Goldbach's Projection, according to which every
diff --git a/src/main/java/com/thealgorithms/maths/LiouvilleLambdaFunction.java b/src/main/java/com/thealgorithms/maths/Prime/LiouvilleLambdaFunction.java
similarity index 93%
rename from src/main/java/com/thealgorithms/maths/LiouvilleLambdaFunction.java
rename to src/main/java/com/thealgorithms/maths/Prime/LiouvilleLambdaFunction.java
index c0f55f5e3485..73535b3aedae 100644
--- a/src/main/java/com/thealgorithms/maths/LiouvilleLambdaFunction.java
+++ b/src/main/java/com/thealgorithms/maths/Prime/LiouvilleLambdaFunction.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.Prime;
 
 /*
  * Java program for liouville lambda function
@@ -24,7 +24,7 @@ private LiouvilleLambdaFunction() {
      *         -1 when number has odd number of prime factors
      * @throws IllegalArgumentException when number is negative
      */
-    static int liouvilleLambda(int number) {
+    public static int liouvilleLambda(int number) {
         if (number <= 0) {
             // throw exception when number is less than or is zero
             throw new IllegalArgumentException("Number must be greater than zero.");
diff --git a/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java b/src/main/java/com/thealgorithms/maths/Prime/MillerRabinPrimalityCheck.java
similarity index 98%
rename from src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java
rename to src/main/java/com/thealgorithms/maths/Prime/MillerRabinPrimalityCheck.java
index f889213abfcb..debe3a214a32 100644
--- a/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java
+++ b/src/main/java/com/thealgorithms/maths/Prime/MillerRabinPrimalityCheck.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.Prime;
 
 import java.util.Random;
 
diff --git a/src/main/java/com/thealgorithms/maths/MobiusFunction.java b/src/main/java/com/thealgorithms/maths/Prime/MobiusFunction.java
similarity index 96%
rename from src/main/java/com/thealgorithms/maths/MobiusFunction.java
rename to src/main/java/com/thealgorithms/maths/Prime/MobiusFunction.java
index 915d0d9a6dae..3d4e4eff0f03 100644
--- a/src/main/java/com/thealgorithms/maths/MobiusFunction.java
+++ b/src/main/java/com/thealgorithms/maths/Prime/MobiusFunction.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.Prime;
 
 /*
  * Java program for mobius function
@@ -25,7 +25,7 @@ private MobiusFunction() {
      *          0 when number has repeated prime factor
      *         -1 when number has odd number of prime factors
      */
-    static int mobius(int number) {
+    public static int mobius(int number) {
         if (number <= 0) {
             // throw exception when number is less than or is zero
             throw new IllegalArgumentException("Number must be greater than zero.");
diff --git a/src/main/java/com/thealgorithms/maths/PrimeCheck.java b/src/main/java/com/thealgorithms/maths/Prime/PrimeCheck.java
similarity index 98%
rename from src/main/java/com/thealgorithms/maths/PrimeCheck.java
rename to src/main/java/com/thealgorithms/maths/Prime/PrimeCheck.java
index 628a819aeba4..91c490f70aef 100644
--- a/src/main/java/com/thealgorithms/maths/PrimeCheck.java
+++ b/src/main/java/com/thealgorithms/maths/Prime/PrimeCheck.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.Prime;
 
 import java.util.Scanner;
 
diff --git a/src/main/java/com/thealgorithms/maths/PrimeFactorization.java b/src/main/java/com/thealgorithms/maths/Prime/PrimeFactorization.java
similarity index 95%
rename from src/main/java/com/thealgorithms/maths/PrimeFactorization.java
rename to src/main/java/com/thealgorithms/maths/Prime/PrimeFactorization.java
index 9ac50fd9043b..e12002b3d8c7 100644
--- a/src/main/java/com/thealgorithms/maths/PrimeFactorization.java
+++ b/src/main/java/com/thealgorithms/maths/Prime/PrimeFactorization.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.Prime;
 
 /*
  * Authors:
diff --git a/src/main/java/com/thealgorithms/maths/SquareFreeInteger.java b/src/main/java/com/thealgorithms/maths/Prime/SquareFreeInteger.java
similarity index 97%
rename from src/main/java/com/thealgorithms/maths/SquareFreeInteger.java
rename to src/main/java/com/thealgorithms/maths/Prime/SquareFreeInteger.java
index 22e9fee00605..15c0a8a691cd 100644
--- a/src/main/java/com/thealgorithms/maths/SquareFreeInteger.java
+++ b/src/main/java/com/thealgorithms/maths/Prime/SquareFreeInteger.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.Prime;
 /*
  * Java program for Square free integer
  * This class has a function which checks
diff --git a/src/main/java/com/thealgorithms/maths/TwinPrime.java b/src/main/java/com/thealgorithms/maths/TwinPrime.java
index ef8de0d1018e..f4e546a2d7a4 100644
--- a/src/main/java/com/thealgorithms/maths/TwinPrime.java
+++ b/src/main/java/com/thealgorithms/maths/TwinPrime.java
@@ -9,6 +9,8 @@
  *
  * */
 
+import com.thealgorithms.maths.Prime.PrimeCheck;
+
 public final class TwinPrime {
     private TwinPrime() {
     }
diff --git a/src/main/java/com/thealgorithms/maths/MatrixRank.java b/src/main/java/com/thealgorithms/matrix/MatrixRank.java
similarity index 77%
rename from src/main/java/com/thealgorithms/maths/MatrixRank.java
rename to src/main/java/com/thealgorithms/matrix/MatrixRank.java
index 7a628b92dccb..6692b6c37c60 100644
--- a/src/main/java/com/thealgorithms/maths/MatrixRank.java
+++ b/src/main/java/com/thealgorithms/matrix/MatrixRank.java
@@ -1,4 +1,6 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.matrix;
+
+import static com.thealgorithms.matrix.utils.MatrixUtil.validateInputMatrix;
 
 /**
  * This class provides a method to compute the rank of a matrix.
@@ -63,47 +65,6 @@ private static double[][] deepCopy(double[][] matrix) {
         return matrixCopy;
     }
 
-    private static void validateInputMatrix(double[][] matrix) {
-        if (matrix == null) {
-            throw new IllegalArgumentException("The input matrix cannot be null");
-        }
-        if (matrix.length == 0) {
-            throw new IllegalArgumentException("The input matrix cannot be empty");
-        }
-        if (!hasValidRows(matrix)) {
-            throw new IllegalArgumentException("The input matrix cannot have null or empty rows");
-        }
-        if (isJaggedMatrix(matrix)) {
-            throw new IllegalArgumentException("The input matrix cannot be jagged");
-        }
-    }
-
-    private static boolean hasValidRows(double[][] matrix) {
-        for (double[] row : matrix) {
-            if (row == null || row.length == 0) {
-                return false;
-            }
-        }
-        return true;
-    }
-
-    /**
-     * @brief Checks if the input matrix is a jagged matrix.
-     * Jagged matrix is a matrix where the number of columns in each row is not the same.
-     *
-     * @param matrix The input matrix
-     * @return True if the input matrix is a jagged matrix, false otherwise
-     */
-    private static boolean isJaggedMatrix(double[][] matrix) {
-        int numColumns = matrix[0].length;
-        for (double[] row : matrix) {
-            if (row.length != numColumns) {
-                return true;
-            }
-        }
-        return false;
-    }
-
     /**
      * @brief The pivot row is the row in the matrix that is used to eliminate other rows and reduce the matrix to its row echelon form.
      * The pivot row is selected as the first row (from top to bottom) where the value in the current column (the pivot column) is not zero.
diff --git a/src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java b/src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java
index b24fcba75619..3a3055f38732 100644
--- a/src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java
+++ b/src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java
@@ -1,6 +1,9 @@
 package com.thealgorithms.matrix;
 
 // Problem Statement
+
+import com.thealgorithms.matrix.utils.MatrixUtil;
+
 /*
 We have given an array of m x n (where m is the number of rows and n is the number of columns).
 Print the new matrix in such a way that the new matrix is the mirror image of the original matrix.
@@ -17,41 +20,17 @@ public final class MirrorOfMatrix {
     private MirrorOfMatrix() {
     }
 
-    public static int[][] mirrorMatrix(final int[][] originalMatrix) {
-        if (originalMatrix == null) {
-            // Handle invalid input
-            return null;
-        }
-        if (originalMatrix.length == 0) {
-            return new int[0][0];
-        }
-
-        checkInput(originalMatrix);
+    public static double[][] mirrorMatrix(final double[][] originalMatrix) {
+        MatrixUtil.validateInputMatrix(originalMatrix);
 
         int numRows = originalMatrix.length;
         int numCols = originalMatrix[0].length;
 
-        int[][] mirroredMatrix = new int[numRows][numCols];
+        double[][] mirroredMatrix = new double[numRows][numCols];
 
         for (int i = 0; i < numRows; i++) {
-            mirroredMatrix[i] = reverseRow(originalMatrix[i]);
+            mirroredMatrix[i] = MatrixUtil.reverseRow(originalMatrix[i]);
         }
         return mirroredMatrix;
     }
-    private static int[] reverseRow(final int[] inRow) {
-        int[] res = new int[inRow.length];
-        for (int i = 0; i < inRow.length; ++i) {
-            res[i] = inRow[inRow.length - 1 - i];
-        }
-        return res;
-    }
-
-    private static void checkInput(final int[][] matrix) {
-        // Check if all rows have the same number of columns
-        for (int i = 1; i < matrix.length; i++) {
-            if (matrix[i].length != matrix[0].length) {
-                throw new IllegalArgumentException("The input is not a matrix.");
-            }
-        }
-    }
 }
diff --git a/src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java b/src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java
index 9c9f97b93ea4..85852713b9ba 100644
--- a/src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java
+++ b/src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.matrix.matrixexponentiation;
 
-import java.util.Scanner;
+import com.thealgorithms.matrix.utils.MatrixUtil;
+import java.math.BigDecimal;
 
 /**
  * @author Anirudh Buvanesh (https://github.com/anirudhb11) For more information
@@ -12,39 +13,11 @@ private Fibonacci() {
     }
 
     // Exponentiation matrix for Fibonacci sequence
-    private static final int[][] FIB_MATRIX = {{1, 1}, {1, 0}};
-    private static final int[][] IDENTITY_MATRIX = {{1, 0}, {0, 1}};
-    // First 2 fibonacci numbers
-    private static final int[][] BASE_FIB_NUMBERS = {{1}, {0}};
+    private static final BigDecimal ONE = BigDecimal.valueOf(1);
+    private static final BigDecimal ZERO = BigDecimal.valueOf(0);
 
-    /**
-     * Performs multiplication of 2 matrices
-     *
-     * @param matrix1
-     * @param matrix2
-     * @return The product of matrix1 and matrix2
-     */
-    private static int[][] matrixMultiplication(int[][] matrix1, int[][] matrix2) {
-        // Check if matrices passed can be multiplied
-        int rowsInMatrix1 = matrix1.length;
-        int columnsInMatrix1 = matrix1[0].length;
-
-        int rowsInMatrix2 = matrix2.length;
-        int columnsInMatrix2 = matrix2[0].length;
-
-        assert columnsInMatrix1 == rowsInMatrix2;
-        int[][] product = new int[rowsInMatrix1][columnsInMatrix2];
-        for (int rowIndex = 0; rowIndex < rowsInMatrix1; rowIndex++) {
-            for (int colIndex = 0; colIndex < columnsInMatrix2; colIndex++) {
-                int matrixEntry = 0;
-                for (int intermediateIndex = 0; intermediateIndex < columnsInMatrix1; intermediateIndex++) {
-                    matrixEntry += matrix1[rowIndex][intermediateIndex] * matrix2[intermediateIndex][colIndex];
-                }
-                product[rowIndex][colIndex] = matrixEntry;
-            }
-        }
-        return product;
-    }
+    private static final BigDecimal[][] FIB_MATRIX = {{ONE, ONE}, {ONE, ZERO}};
+    private static final BigDecimal[][] IDENTITY_MATRIX = {{ONE, ZERO}, {ZERO, ONE}};
 
     /**
      * Calculates the fibonacci number using matrix exponentiaition technique
@@ -53,26 +26,17 @@ private static int[][] matrixMultiplication(int[][] matrix1, int[][] matrix2) {
      * Outputs the nth * fibonacci number
      * @return a 2 X 1 array as { {F_n+1}, {F_n} }
      */
-    public static int[][] fib(int n) {
+    public static BigDecimal[][] fib(int n) {
         if (n == 0) {
             return IDENTITY_MATRIX;
         } else {
-            int[][] cachedResult = fib(n / 2);
-            int[][] matrixExpResult = matrixMultiplication(cachedResult, cachedResult);
+            BigDecimal[][] cachedResult = fib(n / 2);
+            BigDecimal[][] matrixExpResult = MatrixUtil.multiply(cachedResult, cachedResult).get();
             if (n % 2 == 0) {
                 return matrixExpResult;
             } else {
-                return matrixMultiplication(FIB_MATRIX, matrixExpResult);
+                return MatrixUtil.multiply(FIB_MATRIX, matrixExpResult).get();
             }
         }
     }
-
-    public static void main(String[] args) {
-        // Returns [0, 1, 1, 2, 3, 5 ..] for n = [0, 1, 2, 3, 4, 5.. ]
-        Scanner sc = new Scanner(System.in);
-        int n = sc.nextInt();
-        int[][] result = matrixMultiplication(fib(n), BASE_FIB_NUMBERS);
-        System.out.println("Fib(" + n + ") = " + result[1][0]);
-        sc.close();
-    }
 }
diff --git a/src/main/java/com/thealgorithms/maths/MatrixUtil.java b/src/main/java/com/thealgorithms/matrix/utils/MatrixUtil.java
similarity index 62%
rename from src/main/java/com/thealgorithms/maths/MatrixUtil.java
rename to src/main/java/com/thealgorithms/matrix/utils/MatrixUtil.java
index 7e462f92e185..5ff9e37f6b9a 100644
--- a/src/main/java/com/thealgorithms/maths/MatrixUtil.java
+++ b/src/main/java/com/thealgorithms/matrix/utils/MatrixUtil.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.matrix.utils;
 
 import java.math.BigDecimal;
 import java.util.Optional;
@@ -10,6 +10,7 @@
  * @date: 31 October 2021 (Sunday)
  */
 public final class MatrixUtil {
+
     private MatrixUtil() {
     }
 
@@ -18,11 +19,52 @@ private static boolean isValid(final BigDecimal[][] matrix) {
     }
 
     private static boolean hasEqualSizes(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2) {
-        return (isValid(matrix1) && isValid(matrix2) && matrix1.length == matrix2.length && matrix1[0].length == matrix2[0].length);
+        return isValid(matrix1) && isValid(matrix2) && matrix1.length == matrix2.length && matrix1[0].length == matrix2[0].length;
     }
 
     private static boolean canMultiply(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2) {
-        return (isValid(matrix1) && isValid(matrix2) && matrix1[0].length == matrix2.length);
+        return isValid(matrix1) && isValid(matrix2) && matrix1[0].length == matrix2.length;
+    }
+
+    public static void validateInputMatrix(double[][] matrix) {
+        if (matrix == null) {
+            throw new IllegalArgumentException("The input matrix cannot be null");
+        }
+        if (matrix.length == 0) {
+            throw new IllegalArgumentException("The input matrix cannot be empty");
+        }
+        if (!hasValidRows(matrix)) {
+            throw new IllegalArgumentException("The input matrix cannot have null or empty rows");
+        }
+        if (isJaggedMatrix(matrix)) {
+            throw new IllegalArgumentException("The input matrix cannot be jagged");
+        }
+    }
+
+    private static boolean hasValidRows(double[][] matrix) {
+        for (double[] row : matrix) {
+            if (row == null || row.length == 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * @brief Checks if the input matrix is a jagged matrix.
+     * Jagged matrix is a matrix where the number of columns in each row is not the same.
+     *
+     * @param matrix The input matrix
+     * @return True if the input matrix is a jagged matrix, false otherwise
+     */
+    private static boolean isJaggedMatrix(double[][] matrix) {
+        int numColumns = matrix[0].length;
+        for (double[] row : matrix) {
+            if (row.length != numColumns) {
+                return true;
+            }
+        }
+        return false;
     }
 
     private static Optional<BigDecimal[][]> operate(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2, final BiFunction<BigDecimal, BigDecimal, BigDecimal> operation) {
@@ -80,4 +122,12 @@ public static Optional<BigDecimal[][]> multiply(final BigDecimal[][] matrix1, fi
 
         return Optional.of(result);
     }
+
+    public static double[] reverseRow(final double[] inRow) {
+        double[] res = new double[inRow.length];
+        for (int i = 0; i < inRow.length; ++i) {
+            res[i] = inRow[inRow.length - 1 - i];
+        }
+        return res;
+    }
 }
diff --git a/src/main/java/com/thealgorithms/others/Sudoku.java b/src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java
similarity index 99%
rename from src/main/java/com/thealgorithms/others/Sudoku.java
rename to src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java
index 0e88aee46f4d..fce665c4de00 100644
--- a/src/main/java/com/thealgorithms/others/Sudoku.java
+++ b/src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.puzzlesandgames;
 
 /**
  * A class that provides methods to solve Sudoku puzzles of any n x n size
diff --git a/src/main/java/com/thealgorithms/others/TowerOfHanoi.java b/src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java
similarity index 98%
rename from src/main/java/com/thealgorithms/others/TowerOfHanoi.java
rename to src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java
index 7017ed03f843..72e9a14ac070 100644
--- a/src/main/java/com/thealgorithms/others/TowerOfHanoi.java
+++ b/src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.puzzlesandgames;
 
 import java.util.List;
 
diff --git a/src/main/java/com/thealgorithms/misc/WordBoggle.java b/src/main/java/com/thealgorithms/puzzlesandgames/WordBoggle.java
similarity index 98%
rename from src/main/java/com/thealgorithms/misc/WordBoggle.java
rename to src/main/java/com/thealgorithms/puzzlesandgames/WordBoggle.java
index 8b629d68209b..ca1430f744ab 100644
--- a/src/main/java/com/thealgorithms/misc/WordBoggle.java
+++ b/src/main/java/com/thealgorithms/puzzlesandgames/WordBoggle.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.puzzlesandgames;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -8,9 +8,9 @@
 import java.util.Set;
 
 public final class WordBoggle {
+
     private WordBoggle() {
     }
-
     /**
      * O(nm * 8^s + ws) time where n = width of boggle board, m = height of
      * boggle board, s = length of longest word in string array, w = length of
diff --git a/src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java b/src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java
index d7e16e02602b..5b35ee7bd9d0 100644
--- a/src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java
+++ b/src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java
@@ -3,6 +3,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import com.thealgorithms.maths.Prime.SquareFreeInteger;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java b/src/test/java/com/thealgorithms/maths/prime/LiouvilleLambdaFunctionTest.java
similarity index 94%
rename from src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java
rename to src/test/java/com/thealgorithms/maths/prime/LiouvilleLambdaFunctionTest.java
index a2763047acf0..d32815c0b8a9 100644
--- a/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java
+++ b/src/test/java/com/thealgorithms/maths/prime/LiouvilleLambdaFunctionTest.java
@@ -1,8 +1,9 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.prime;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import com.thealgorithms.maths.Prime.LiouvilleLambdaFunction;
 import org.junit.jupiter.api.Test;
 
 class LiouvilleLambdaFunctionTest {
diff --git a/src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java b/src/test/java/com/thealgorithms/maths/prime/MillerRabinPrimalityCheckTest.java
similarity index 92%
rename from src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java
rename to src/test/java/com/thealgorithms/maths/prime/MillerRabinPrimalityCheckTest.java
index d547cecf24cd..4defcd587758 100644
--- a/src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java
+++ b/src/test/java/com/thealgorithms/maths/prime/MillerRabinPrimalityCheckTest.java
@@ -1,8 +1,9 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.prime;
 
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import com.thealgorithms.maths.Prime.MillerRabinPrimalityCheck;
 import org.junit.jupiter.api.Test;
 
 class MillerRabinPrimalityCheckTest {
diff --git a/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java b/src/test/java/com/thealgorithms/maths/prime/MobiusFunctionTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java
rename to src/test/java/com/thealgorithms/maths/prime/MobiusFunctionTest.java
index f3a6514ce633..734d02477ba2 100644
--- a/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java
+++ b/src/test/java/com/thealgorithms/maths/prime/MobiusFunctionTest.java
@@ -1,8 +1,9 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.prime;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import com.thealgorithms.maths.Prime.MobiusFunction;
 import org.junit.jupiter.api.Test;
 
 class MobiusFunctionTest {
diff --git a/src/test/java/com/thealgorithms/maths/PrimeCheckTest.java b/src/test/java/com/thealgorithms/maths/prime/PrimeCheckTest.java
similarity index 89%
rename from src/test/java/com/thealgorithms/maths/PrimeCheckTest.java
rename to src/test/java/com/thealgorithms/maths/prime/PrimeCheckTest.java
index c3e1634c51fe..2182bcd9cb16 100644
--- a/src/test/java/com/thealgorithms/maths/PrimeCheckTest.java
+++ b/src/test/java/com/thealgorithms/maths/prime/PrimeCheckTest.java
@@ -1,5 +1,6 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.prime;
 
+import com.thealgorithms.maths.Prime.PrimeCheck;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
diff --git a/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java b/src/test/java/com/thealgorithms/maths/prime/PrimeFactorizationTest.java
similarity index 93%
rename from src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java
rename to src/test/java/com/thealgorithms/maths/prime/PrimeFactorizationTest.java
index 6994379d736a..79d685726261 100644
--- a/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java
+++ b/src/test/java/com/thealgorithms/maths/prime/PrimeFactorizationTest.java
@@ -1,7 +1,8 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.maths.prime;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import com.thealgorithms.maths.Prime.PrimeFactorization;
 import java.util.List;
 import java.util.stream.Stream;
 import org.junit.jupiter.params.ParameterizedTest;
diff --git a/src/test/java/com/thealgorithms/maths/MatrixRankTest.java b/src/test/java/com/thealgorithms/matrix/MatrixRankTest.java
similarity index 98%
rename from src/test/java/com/thealgorithms/maths/MatrixRankTest.java
rename to src/test/java/com/thealgorithms/matrix/MatrixRankTest.java
index 415b84ec43f8..33a0196b7bf7 100644
--- a/src/test/java/com/thealgorithms/maths/MatrixRankTest.java
+++ b/src/test/java/com/thealgorithms/matrix/MatrixRankTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.matrix;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
diff --git a/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java b/src/test/java/com/thealgorithms/matrix/MatrixUtilTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/maths/MatrixUtilTest.java
rename to src/test/java/com/thealgorithms/matrix/MatrixUtilTest.java
index b954e6ff7511..78947b1e70cb 100644
--- a/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java
+++ b/src/test/java/com/thealgorithms/matrix/MatrixUtilTest.java
@@ -1,7 +1,8 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.matrix;
 
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import com.thealgorithms.matrix.utils.MatrixUtil;
 import java.math.BigDecimal;
 import java.util.Objects;
 import org.junit.jupiter.api.Test;
diff --git a/src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java b/src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java
index 2d68e1faaa17..2e4370922370 100644
--- a/src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java
+++ b/src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java
@@ -1,7 +1,7 @@
 package com.thealgorithms.matrix;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
@@ -10,44 +10,44 @@ class MirrorOfMatrixTest {
 
     @Test
     void testMirrorMatrixRegularMatrix() {
-        int[][] originalMatrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
-        int[][] expectedMirrorMatrix = {{3, 2, 1}, {6, 5, 4}, {9, 8, 7}};
-        int[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
+        double[][] originalMatrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+        double[][] expectedMirrorMatrix = {{3, 2, 1}, {6, 5, 4}, {9, 8, 7}};
+        double[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
         assertArrayEquals(expectedMirrorMatrix, mirroredMatrix);
     }
 
     @Test
     void testMirrorMatrixEmptyMatrix() {
-        int[][] originalMatrix = {};
-        int[][] expectedMirrorMatrix = {};
-        int[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
-        assertArrayEquals(expectedMirrorMatrix, mirroredMatrix);
+        double[][] originalMatrix = {};
+        Exception e = assertThrows(IllegalArgumentException.class, () -> MirrorOfMatrix.mirrorMatrix(originalMatrix));
+        assertEquals("The input matrix cannot be empty", e.getMessage());
     }
 
     @Test
     void testMirrorMatrixSingleElementMatrix() {
-        int[][] originalMatrix = {{42}};
-        int[][] expectedMirrorMatrix = {{42}};
-        int[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
+        double[][] originalMatrix = {{42}};
+        double[][] expectedMirrorMatrix = {{42}};
+        double[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
         assertArrayEquals(expectedMirrorMatrix, mirroredMatrix);
     }
 
     @Test
     void testMirrorMatrixMultipleRowsOneColumnMatrix() {
-        int[][] originalMatrix = {{1}, {2}, {3}, {4}};
-        int[][] expectedMirrorMatrix = {{1}, {2}, {3}, {4}};
-        int[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
+        double[][] originalMatrix = {{1}, {2}, {3}, {4}};
+        double[][] expectedMirrorMatrix = {{1}, {2}, {3}, {4}};
+        double[][] mirroredMatrix = MirrorOfMatrix.mirrorMatrix(originalMatrix);
         assertArrayEquals(expectedMirrorMatrix, mirroredMatrix);
     }
 
     @Test
     void testMirrorMatrixNullInput() {
-        int[][] originalMatrix = null;
-        assertNull(MirrorOfMatrix.mirrorMatrix(originalMatrix));
+        double[][] originalMatrix = null;
+        Exception e = assertThrows(IllegalArgumentException.class, () -> MirrorOfMatrix.mirrorMatrix(originalMatrix));
+        assertEquals("The input matrix cannot be null", e.getMessage());
     }
 
     @Test
-    void testMirrotMarixThrows() {
-        assertThrows(IllegalArgumentException.class, () -> MirrorOfMatrix.mirrorMatrix(new int[][] {{1}, {2, 3}}));
+    void testMirrorMatrixThrows() {
+        assertThrows(IllegalArgumentException.class, () -> MirrorOfMatrix.mirrorMatrix(new double[][] {{1}, {2, 3}}));
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/SudokuTest.java b/src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java
similarity index 97%
rename from src/test/java/com/thealgorithms/others/SudokuTest.java
rename to src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java
index 5018b2768302..7fb96dcf805f 100644
--- a/src/test/java/com/thealgorithms/others/SudokuTest.java
+++ b/src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.puzzlesandgames;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
diff --git a/src/test/java/com/thealgorithms/others/TowerOfHanoiTest.java b/src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java
similarity index 97%
rename from src/test/java/com/thealgorithms/others/TowerOfHanoiTest.java
rename to src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java
index ca9376dd48eb..42669eb03bb4 100644
--- a/src/test/java/com/thealgorithms/others/TowerOfHanoiTest.java
+++ b/src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.puzzlesandgames;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
diff --git a/src/test/java/com/thealgorithms/misc/WordBoggleTest.java b/src/test/java/com/thealgorithms/puzzlesandgames/WordBoggleTest.java
similarity index 98%
rename from src/test/java/com/thealgorithms/misc/WordBoggleTest.java
rename to src/test/java/com/thealgorithms/puzzlesandgames/WordBoggleTest.java
index 1d4ed7c5e737..ef5d3c92eb5e 100644
--- a/src/test/java/com/thealgorithms/misc/WordBoggleTest.java
+++ b/src/test/java/com/thealgorithms/puzzlesandgames/WordBoggleTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.puzzlesandgames;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;

From 4d667e1b76001617f83b4ad1e662a0af14117c28 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 27 Jan 2025 22:23:25 +0100
Subject: [PATCH 0752/1338] Bump com.puppycrawl.tools:checkstyle from 10.21.1
 to 10.21.2 (#6154)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.21.1 to 10.21.2.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.21.1...checkstyle-10.21.2)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index d246f378ba71..7900c6f2d956 100644
--- a/pom.xml
+++ b/pom.xml
@@ -125,7 +125,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.21.1</version>
+                    <version>10.21.2</version>
                     </dependency>
                 </dependencies>
             </plugin>

From d4b28b348e0ccd7423d0981499f85958382d1522 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Tue, 28 Jan 2025 11:33:58 +0100
Subject: [PATCH 0753/1338] Add Constrained Shortest Path Problem (CSPP) /
 Shortest Path Problem with Resource Constraints (SPPRC) (#6155)

---
 .../graph/ConstrainedShortestPath.java        | 123 ++++++++++
 .../graph/ConstrainedShortestPathTest.java    | 218 ++++++++++++++++++
 2 files changed, 341 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java
 create mode 100644 src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java

diff --git a/src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java b/src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java
new file mode 100644
index 000000000000..f397989911d9
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java
@@ -0,0 +1,123 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * This class implements a solution for the Constrained Shortest Path Problem (CSPP).
+ * also known as Shortest Path Problem with Resource Constraints (SPPRC).
+ * The goal is to find the shortest path between two nodes while ensuring that
+ * the resource constraint is not exceeded.
+ *
+ * @author  <a href="https://github.com/DenizAltunkapan">Deniz Altunkapan</a>
+ */
+public class ConstrainedShortestPath {
+
+    /**
+     * Represents a graph using an adjacency list.
+     * This graph is designed for the Constrained Shortest Path Problem (CSPP).
+     */
+    public static class Graph {
+
+        private List<List<Edge>> adjacencyList;
+
+        public Graph(int numNodes) {
+            adjacencyList = new ArrayList<>();
+            for (int i = 0; i < numNodes; i++) {
+                adjacencyList.add(new ArrayList<>());
+            }
+        }
+
+        /**
+         * Adds an edge to the graph.
+         * @param from the starting node
+         * @param to the ending node
+         * @param cost the cost of the edge
+         * @param resource the resource required to traverse the edge
+         */
+        public void addEdge(int from, int to, int cost, int resource) {
+            adjacencyList.get(from).add(new Edge(from, to, cost, resource));
+        }
+
+        /**
+         * Gets the edges that are adjacent to a given node.
+         * @param node the node to get the edges for
+         * @return the list of edges adjacent to the node
+         */
+        public List<Edge> getEdges(int node) {
+            return adjacencyList.get(node);
+        }
+
+        /**
+         * Gets the number of nodes in the graph.
+         * @return the number of nodes
+         */
+        public int getNumNodes() {
+            return adjacencyList.size();
+        }
+
+        public record Edge(int from, int to, int cost, int resource) {
+        }
+    }
+
+    private Graph graph;
+    private int maxResource;
+
+    /**
+     * Constructs a CSPSolver with the given graph and maximum resource constraint.
+     *
+     * @param graph       the graph representing the problem
+     * @param maxResource the maximum allowable resource
+     */
+    public ConstrainedShortestPath(Graph graph, int maxResource) {
+        this.graph = graph;
+        this.maxResource = maxResource;
+    }
+
+    /**
+     * Solves the CSP to find the shortest path from the start node to the target node
+     * without exceeding the resource constraint.
+     *
+     * @param start  the starting node
+     * @param target the target node
+     * @return the minimum cost to reach the target node within the resource constraint,
+     *         or -1 if no valid path exists
+     */
+    public int solve(int start, int target) {
+        int numNodes = graph.getNumNodes();
+        int[][] dp = new int[maxResource + 1][numNodes];
+
+        // Initialize dp table with maximum values
+        for (int i = 0; i <= maxResource; i++) {
+            Arrays.fill(dp[i], Integer.MAX_VALUE);
+        }
+        dp[0][start] = 0;
+
+        // Dynamic Programming: Iterate over resources and nodes
+        for (int r = 0; r <= maxResource; r++) {
+            for (int u = 0; u < numNodes; u++) {
+                if (dp[r][u] == Integer.MAX_VALUE) {
+                    continue;
+                }
+                for (Graph.Edge edge : graph.getEdges(u)) {
+                    int v = edge.to();
+                    int cost = edge.cost();
+                    int resource = edge.resource();
+
+                    if (r + resource <= maxResource) {
+                        dp[r + resource][v] = Math.min(dp[r + resource][v], dp[r][u] + cost);
+                    }
+                }
+            }
+        }
+
+        // Find the minimum cost to reach the target node
+        int minCost = Integer.MAX_VALUE;
+        for (int r = 0; r <= maxResource; r++) {
+            minCost = Math.min(minCost, dp[r][target]);
+        }
+
+        return minCost == Integer.MAX_VALUE ? -1 : minCost;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java b/src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java
new file mode 100644
index 000000000000..eccd359f2634
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java
@@ -0,0 +1,218 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.thealgorithms.graph.ConstrainedShortestPath.Graph;
+import org.junit.jupiter.api.Test;
+
+public class ConstrainedShortestPathTest {
+
+    /**
+     * Tests a simple linear graph to verify if the solver calculates the shortest path correctly.
+     * Expected: The minimal path cost from node 0 to node 2 should be 5 while not exceeding the resource limit.
+     */
+    @Test
+    public void testSimpleGraph() {
+        Graph graph = new Graph(3);
+        graph.addEdge(0, 1, 2, 3);
+        graph.addEdge(1, 2, 3, 2);
+
+        int maxResource = 5;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(5, solver.solve(0, 2));
+    }
+
+    /**
+     * Tests a graph where no valid path exists due to resource constraints.
+     * Expected: The solver should return -1, indicating no path is feasible.
+     */
+    @Test
+    public void testNoPath() {
+        Graph graph = new Graph(3);
+        graph.addEdge(0, 1, 2, 6);
+        graph.addEdge(1, 2, 3, 6);
+
+        int maxResource = 5;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(-1, solver.solve(0, 2));
+    }
+
+    /**
+     * Tests a graph with multiple paths between source and destination.
+     * Expected: The solver should choose the path with the minimal cost of 5, considering the resource limit.
+     */
+    @Test
+    public void testMultiplePaths() {
+        Graph graph = new Graph(4);
+        graph.addEdge(0, 1, 1, 1);
+        graph.addEdge(1, 3, 5, 2);
+        graph.addEdge(0, 2, 2, 1);
+        graph.addEdge(2, 3, 3, 2);
+
+        int maxResource = 3;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(5, solver.solve(0, 3));
+    }
+
+    /**
+     * Verifies that the solver allows a path exactly matching the resource limit.
+     * Expected: The path is valid with a total cost of 5.
+     */
+    @Test
+    public void testExactResourceLimit() {
+        Graph graph = new Graph(3);
+        graph.addEdge(0, 1, 2, 3);
+        graph.addEdge(1, 2, 3, 2);
+
+        int maxResource = 5;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(5, solver.solve(0, 2));
+    }
+
+    /**
+     * Tests a disconnected graph where the destination node cannot be reached.
+     * Expected: The solver should return -1, as the destination is unreachable.
+     */
+    @Test
+    public void testDisconnectedGraph() {
+        Graph graph = new Graph(4);
+        graph.addEdge(0, 1, 2, 2);
+        graph.addEdge(2, 3, 3, 2);
+
+        int maxResource = 5;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(-1, solver.solve(0, 3));
+    }
+
+    /**
+     * Tests a graph with cycles to ensure the solver does not fall into infinite loops and correctly calculates costs.
+     * Expected: The solver should compute the minimal path cost of 6.
+     */
+    @Test
+    public void testGraphWithCycles() {
+        Graph graph = new Graph(4);
+        graph.addEdge(0, 1, 2, 1);
+        graph.addEdge(1, 2, 3, 1);
+        graph.addEdge(2, 0, 1, 1);
+        graph.addEdge(1, 3, 4, 2);
+
+        int maxResource = 3;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(6, solver.solve(0, 3));
+    }
+
+    /**
+     * Tests the solver's performance and correctness on a large linear graph with 1000 nodes.
+     * Expected: The solver should efficiently calculate the shortest path with a cost of 999.
+     */
+    @Test
+    public void testLargeGraphPerformance() {
+        int nodeCount = 1000;
+        Graph graph = new Graph(nodeCount);
+        for (int i = 0; i < nodeCount - 1; i++) {
+            graph.addEdge(i, i + 1, 1, 1);
+        }
+
+        int maxResource = 1000;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(999, solver.solve(0, nodeCount - 1));
+    }
+
+    /**
+     * Tests a graph with isolated nodes to ensure the solver recognizes unreachable destinations.
+     * Expected: The solver should return -1 for unreachable nodes.
+     */
+    @Test
+    public void testIsolatedNodes() {
+        Graph graph = new Graph(5);
+        graph.addEdge(0, 1, 2, 1);
+        graph.addEdge(1, 2, 3, 1);
+
+        int maxResource = 5;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(-1, solver.solve(0, 3));
+    }
+
+    /**
+     * Tests a cyclic large graph with multiple overlapping paths.
+     * Expected: The solver should calculate the shortest path cost of 5.
+     */
+    @Test
+    public void testCyclicLargeGraph() {
+        Graph graph = new Graph(10);
+        for (int i = 0; i < 9; i++) {
+            graph.addEdge(i, (i + 1) % 10, 1, 1);
+        }
+        graph.addEdge(0, 5, 5, 3);
+
+        int maxResource = 10;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(5, solver.solve(0, 5));
+    }
+
+    /**
+     * Tests a large complex graph with multiple paths and varying resource constraints.
+     * Expected: The solver should identify the optimal path with a cost of 19 within the resource limit.
+     */
+    @Test
+    public void testLargeComplexGraph() {
+        Graph graph = new Graph(10);
+        graph.addEdge(0, 1, 4, 2);
+        graph.addEdge(0, 2, 3, 3);
+        graph.addEdge(1, 3, 2, 1);
+        graph.addEdge(2, 3, 5, 2);
+        graph.addEdge(2, 4, 8, 4);
+        graph.addEdge(3, 5, 7, 3);
+        graph.addEdge(3, 6, 6, 2);
+        graph.addEdge(4, 6, 3, 2);
+        graph.addEdge(5, 7, 1, 1);
+        graph.addEdge(6, 7, 2, 2);
+        graph.addEdge(7, 8, 3, 1);
+        graph.addEdge(8, 9, 2, 1);
+
+        int maxResource = 10;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(19, solver.solve(0, 9));
+    }
+
+    /**
+     * Edge case test where the graph has only one node and no edges.
+     * Expected: The minimal path cost is 0, as the start and destination are the same.
+     */
+    @Test
+    public void testSingleNodeGraph() {
+        Graph graph = new Graph(1);
+
+        int maxResource = 0;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(0, solver.solve(0, 0));
+    }
+
+    /**
+     * Tests a graph with multiple paths but a tight resource constraint.
+     * Expected: The solver should return -1 if no path can be found within the resource limit.
+     */
+    @Test
+    public void testTightResourceConstraint() {
+        Graph graph = new Graph(4);
+        graph.addEdge(0, 1, 3, 4);
+        graph.addEdge(1, 2, 1, 2);
+        graph.addEdge(0, 2, 2, 2);
+
+        int maxResource = 3;
+        ConstrainedShortestPath solver = new ConstrainedShortestPath(graph, maxResource);
+
+        assertEquals(2, solver.solve(0, 2));
+    }
+}

From 3313ddc7233a3b7751cdf3ccdd0954bf27c1f865 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 10 Feb 2025 21:34:14 +0000
Subject: [PATCH 0754/1338] Bump gitpod/workspace-java-21 from
 2024-11-26-08-43-19 to 2025-02-10-10-54-28 (#6162)

Bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2024-11-26-08-43-19 to 2025-02-10-10-54-28.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 4b1885ffa388..ea6d32a5a377 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-11-26-08-43-19
+FROM gitpod/workspace-java-21:2025-02-10-10-54-28
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 63ce6b8ca57e99203dbc5129a50662d5cc48799e Mon Sep 17 00:00:00 2001
From: Niklas Hoefflin <122729995+itakurah@users.noreply.github.com>
Date: Thu, 13 Feb 2025 21:33:52 +0100
Subject: [PATCH 0755/1338] Refactor LWWElementSet (#6164)

---
 DIRECTORY.md                                  |  51 +++---
 .../datastructures/crdt/LWWElementSet.java    | 170 ++++++++----------
 .../crdt/LWWElementSetTest.java               | 120 ++++++-------
 3 files changed, 164 insertions(+), 177 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 4fa1392a3c17..6ccaf0b38e7f 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -332,6 +332,7 @@
             * [MidpointEllipse](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/MidpointEllipse.java)
             * [Point](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/Point.java)
           * graph
+            * [ConstrainedShortestPath](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java)
             * [StronglyConnectedComponentOptimized](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
           * greedyalgorithms
             * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
@@ -419,18 +420,13 @@
             * [LeastCommonMultiple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java)
             * [LeonardoNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LeonardoNumber.java)
             * [LinearDiophantineEquationsSolver](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java)
-            * [LiouvilleLambdaFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LiouvilleLambdaFunction.java)
             * [LongDivision](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LongDivision.java)
             * [LucasSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LucasSeries.java)
             * [MagicSquare](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MagicSquare.java)
-            * [MatrixRank](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MatrixRank.java)
-            * [MatrixUtil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MatrixUtil.java)
             * [MaxValue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MaxValue.java)
             * [Means](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Means.java)
             * [Median](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Median.java)
-            * [MillerRabinPrimalityCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MillerRabinPrimalityCheck.java)
             * [MinValue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MinValue.java)
-            * [MobiusFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MobiusFunction.java)
             * [Mode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Mode.java)
             * [NonRepeatingElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java)
             * [NthUglyNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/NthUglyNumber.java)
@@ -447,8 +443,13 @@
             * [Pow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Pow.java)
             * [PowerOfTwoOrNot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PowerOfTwoOrNot.java)
             * [PowerUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PowerUsingRecursion.java)
-            * [PrimeCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PrimeCheck.java)
-            * [PrimeFactorization](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PrimeFactorization.java)
+            * Prime
+              * [LiouvilleLambdaFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/LiouvilleLambdaFunction.java)
+              * [MillerRabinPrimalityCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/MillerRabinPrimalityCheck.java)
+              * [MobiusFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/MobiusFunction.java)
+              * [PrimeCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/PrimeCheck.java)
+              * [PrimeFactorization](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/PrimeFactorization.java)
+              * [SquareFreeInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/SquareFreeInteger.java)
             * [PronicNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PronicNumber.java)
             * [PythagoreanTriple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java)
             * [QuadraticEquationSolver](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/QuadraticEquationSolver.java)
@@ -458,7 +459,6 @@
             * [SieveOfEratosthenes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java)
             * [SimpsonIntegration](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java)
             * [SolovayStrassenPrimalityTest](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java)
-            * [SquareFreeInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareFreeInteger.java)
             * [SquareRootWithBabylonianMethod](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java)
             * [SquareRootWithNewtonRaphsonMethod](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonMethod.java)
             * [StandardDeviation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/StandardDeviation.java)
@@ -478,11 +478,14 @@
             * [InverseOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/InverseOfMatrix.java)
             * matrixexponentiation
               * [Fibonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java)
+            * [MatrixRank](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MatrixRank.java)
             * [MatrixTranspose](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MatrixTranspose.java)
             * [MedianOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java)
             * [MirrorOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java)
             * [PrintAMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java)
             * [RotateMatrixBy90Degrees](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java)
+            * utils
+              * [MatrixUtil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/utils/MatrixUtil.java)
           * misc
             * [ColorContrastRatio](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java)
             * [MapReduce](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MapReduce.java)
@@ -499,7 +502,6 @@
             * [Sparsity](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sparsity.java)
             * [ThreeSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java)
             * [TwoSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/TwoSumProblem.java)
-            * [WordBoggle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/WordBoggle.java)
           * others
             * [ArrayLeftRotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java)
             * [ArrayRightRotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ArrayRightRotation.java)
@@ -539,10 +541,12 @@
             * [RemoveDuplicateFromString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java)
             * [ReverseStackUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
             * [SkylineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SkylineProblem.java)
-            * [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Sudoku.java)
-            * [TowerOfHanoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TowerOfHanoi.java)
             * [TwoPointers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TwoPointers.java)
             * [Verhoeff](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Verhoeff.java)
+          * puzzlesandgames
+            * [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java)
+            * [TowerOfHanoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java)
+            * [WordBoggle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/puzzlesandgames/WordBoggle.java)
           * recursion
             * [FibonacciSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java)
             * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/recursion/GenerateSubsets.java)
@@ -623,6 +627,7 @@
             * [CombSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CombSort.java)
             * [CountingSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CountingSort.java)
             * [CycleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CycleSort.java)
+            * [DarkSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DarkSort.java)
             * [DualPivotQuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java)
             * [DutchNationalFlagSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java)
             * [ExchangeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/ExchangeSort.java)
@@ -1008,6 +1013,7 @@
             * [MidpointCircleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java)
             * [MidpointEllipseTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java)
           * graph
+            * [ConstrainedShortestPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java)
             * [StronglyConnectedComponentOptimizedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)
           * greedyalgorithms
             * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
@@ -1087,17 +1093,12 @@
             * [KrishnamurthyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java)
             * [LeastCommonMultipleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java)
             * [LeonardoNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java)
-            * [LiouvilleLambdaFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java)
             * [LongDivisionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LongDivisionTest.java)
             * [LucasSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LucasSeriesTest.java)
-            * [MatrixRankTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MatrixRankTest.java)
-            * [MatrixUtilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MatrixUtilTest.java)
             * [MaxValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MaxValueTest.java)
             * [MeansTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MeansTest.java)
             * [MedianTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MedianTest.java)
-            * [MillerRabinPrimalityCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java)
             * [MinValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MinValueTest.java)
-            * [MobiusFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java)
             * [ModeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ModeTest.java)
             * [NonRepeatingElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NonRepeatingElementTest.java)
             * [NthUglyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java)
@@ -1113,8 +1114,12 @@
             * [PowerOfTwoOrNotTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java)
             * [PowerUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java)
             * [PowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowTest.java)
-            * [PrimeCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PrimeCheckTest.java)
-            * [PrimeFactorizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PrimeFactorizationTest.java)
+            * prime
+              * [LiouvilleLambdaFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/prime/LiouvilleLambdaFunctionTest.java)
+              * [MillerRabinPrimalityCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/prime/MillerRabinPrimalityCheckTest.java)
+              * [MobiusFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/prime/MobiusFunctionTest.java)
+              * [PrimeCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/prime/PrimeCheckTest.java)
+              * [PrimeFactorizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/prime/PrimeFactorizationTest.java)
             * [PronicNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PronicNumberTest.java)
             * [PythagoreanTripleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java)
             * [QuadraticEquationSolverTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java)
@@ -1139,7 +1144,9 @@
             * [VolumeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/VolumeTest.java)
           * matrix
             * [InverseOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/InverseOfMatrixTest.java)
+            * [MatrixRankTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MatrixRankTest.java)
             * [MatrixTransposeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MatrixTransposeTest.java)
+            * [MatrixUtilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MatrixUtilTest.java)
             * [MedianOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java)
             * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java)
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java)
@@ -1154,7 +1161,6 @@
             * [SparsityTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/SparsityTest.java)
             * [ThreeSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java)
             * [TwoSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
-            * [WordBoggleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/WordBoggleTest.java)
           * others
             * [ArrayLeftRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java)
             * [ArrayRightRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java)
@@ -1182,10 +1188,12 @@
             * [RemoveDuplicateFromStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java)
             * [ReverseStackUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
             * [SkylineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
-            * [SudokuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SudokuTest.java)
-            * [TowerOfHanoiTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TowerOfHanoiTest.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
+          * puzzlesandgames
+            * [SudokuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java)
+            * [TowerOfHanoiTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java)
+            * [WordBoggleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/puzzlesandgames/WordBoggleTest.java)
           * recursion
             * [FibonacciSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/recursion/FibonacciSeriesTest.java)
             * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java)
@@ -1267,6 +1275,7 @@
             * [CombSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CombSortTest.java)
             * [CountingSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CountingSortTest.java)
             * [CycleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CycleSortTest.java)
+            * [DarkSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DarkSortTest.java)
             * [DualPivotQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java)
             * [DutchNationalFlagSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java)
             * [ExchangeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/ExchangeSortTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java b/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
index 2c6ce8a427d1..d33bd3ee84d9 100644
--- a/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java
@@ -1,53 +1,33 @@
 package com.thealgorithms.datastructures.crdt;
 
+import java.time.Instant;
 import java.util.HashMap;
 import java.util.Map;
 
 /**
- * Last-Write-Wins Element Set (LWWElementSet) is a state-based CRDT (Conflict-free Replicated Data Type)
- * designed for managing sets in a distributed and concurrent environment. It supports the addition and removal
- * of elements, using timestamps to determine the order of operations. The set is split into two subsets:
- * the add set for elements to be added and the remove set for elements to be removed.
+ * Last-Write-Wins Element Set (LWWElementSet) is a state-based CRDT (Conflict-free Replicated Data
+ * Type) designed for managing sets in a distributed and concurrent environment. It supports the
+ * addition and removal of elements, using timestamps to determine the order of operations. The set
+ * is split into two subsets: the add set for elements to be added and the remove set for elements
+ * to be removed. The LWWElementSet ensures that the most recent operation (based on the timestamp)
+ * wins in the case of concurrent operations.
  *
- * @author itakurah (Niklas Hoefflin) (https://github.com/itakurah)
- * @see <a href="https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type">Conflict-free_replicated_data_type</a>
- * @see <a href="https://github.com/itakurah">itakurah (Niklas Hoefflin)</a>
+ * @param <T> The type of the elements in the LWWElementSet.
+ * @author <a href="https://github.com/itakurah">itakurah (GitHub)</a>, <a
+ * href="https://www.linkedin.com/in/niklashoefflin/">Niklas Hoefflin (LinkedIn)</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type">Conflict free
+ * replicated data type (Wikipedia)</a>
+ * @see <a href="https://inria.hal.science/inria-00555588v1/document">A comprehensive study of
+ * Convergent and Commutative Replicated Data Types</a>
  */
-
-class Element {
-    String key;
-    int timestamp;
-    Bias bias;
+class LWWElementSet<T> {
+    final Map<T, Element<T>> addSet;
+    final Map<T, Element<T>> removeSet;
 
     /**
-     * Constructs a new Element with the specified key, timestamp and bias.
-     *
-     * @param key       The key of the element.
-     * @param timestamp The timestamp associated with the element.
-     * @param bias      The bias of the element (ADDS or REMOVALS).
-     */
-    Element(String key, int timestamp, Bias bias) {
-        this.key = key;
-        this.timestamp = timestamp;
-        this.bias = bias;
-    }
-}
-
-enum Bias {
-    /**
-     * ADDS bias for the add set.
-     * REMOVALS bias for the remove set.
-     */
-    ADDS,
-    REMOVALS
-}
-
-class LWWElementSet {
-    private final Map<String, Element> addSet;
-    private final Map<String, Element> removeSet;
-
-    /**
-     * Constructs an empty LWWElementSet.
+     * Constructs an empty LWWElementSet. This constructor initializes the addSet and removeSet as
+     * empty HashMaps. The addSet stores elements that are added, and the removeSet stores elements
+     * that are removed.
      */
     LWWElementSet() {
         this.addSet = new HashMap<>();
@@ -55,84 +35,92 @@ class LWWElementSet {
     }
 
     /**
-     * Adds an element to the addSet.
+     * Adds an element to the addSet with the current timestamp. This method stores the element in the
+     * addSet, ensuring that the element is added to the set with an associated timestamp that
+     * represents the time of the addition.
      *
-     * @param e The element to be added.
+     * @param key The key of the element to be added.
      */
-    public void add(Element e) {
-        addSet.put(e.key, e);
+    public void add(T key) {
+        addSet.put(key, new Element<>(key, Instant.now()));
     }
 
     /**
-     * Removes an element from the removeSet.
+     * Removes an element by adding it to the removeSet with the current timestamp. This method adds
+     * the element to the removeSet, marking it as removed with the current timestamp.
      *
-     * @param e The element to be removed.
+     * @param key The key of the element to be removed.
      */
-    public void remove(Element e) {
-        if (lookup(e)) {
-            removeSet.put(e.key, e);
-        }
+    public void remove(T key) {
+        removeSet.put(key, new Element<>(key, Instant.now()));
     }
 
     /**
-     * Checks if an element is in the LWWElementSet by comparing timestamps in the addSet and removeSet.
+     * Checks if an element is in the LWWElementSet. An element is considered present if it exists in
+     * the addSet and either does not exist in the removeSet, or its add timestamp is later than any
+     * corresponding remove timestamp.
      *
-     * @param e The element to be checked.
-     * @return True if the element is present, false otherwise.
+     * @param key The key of the element to be checked.
+     * @return {@code true} if the element is present in the set (i.e., its add timestamp is later
+     * than its remove timestamp, or it is not in the remove set), {@code false} otherwise (i.e.,
+     * the element has been removed or its remove timestamp is later than its add timestamp).
      */
-    public boolean lookup(Element e) {
-        Element inAddSet = addSet.get(e.key);
-        Element inRemoveSet = removeSet.get(e.key);
+    public boolean lookup(T key) {
+        Element<T> inAddSet = addSet.get(key);
+        Element<T> inRemoveSet = removeSet.get(key);
 
-        return (inAddSet != null && (inRemoveSet == null || inAddSet.timestamp > inRemoveSet.timestamp));
+        return inAddSet != null && (inRemoveSet == null || inAddSet.timestamp.isAfter(inRemoveSet.timestamp));
     }
 
     /**
-     * Compares the LWWElementSet with another LWWElementSet to check if addSet and removeSet are a subset.
+     * Merges another LWWElementSet into this set. This method takes the union of both the add-sets
+     * and remove-sets from the two sets, resolving conflicts by keeping the element with the latest
+     * timestamp. If an element appears in both the add-set and remove-set of both sets, the one with
+     * the later timestamp will be retained.
      *
-     * @param other The LWWElementSet to compare.
-     * @return True if the set is subset, false otherwise.
+     * @param other The LWWElementSet to merge with the current set.
      */
-    public boolean compare(LWWElementSet other) {
-        return other.addSet.keySet().containsAll(addSet.keySet()) && other.removeSet.keySet().containsAll(removeSet.keySet());
+    public void merge(LWWElementSet<T> other) {
+        for (Map.Entry<T, Element<T>> entry : other.addSet.entrySet()) {
+            addSet.merge(entry.getKey(), entry.getValue(), this::resolveConflict);
+        }
+        for (Map.Entry<T, Element<T>> entry : other.removeSet.entrySet()) {
+            removeSet.merge(entry.getKey(), entry.getValue(), this::resolveConflict);
+        }
     }
 
     /**
-     * Merges another LWWElementSet into this set by resolving conflicts based on timestamps.
+     * Resolves conflicts between two elements by selecting the one with the later timestamp. This
+     * method is used when merging two LWWElementSets to ensure that the most recent operation (based
+     * on timestamps) is kept.
      *
-     * @param other The LWWElementSet to merge.
+     * @param e1 The first element.
+     * @param e2 The second element.
+     * @return The element with the later timestamp.
      */
-    public void merge(LWWElementSet other) {
-        for (Element e : other.addSet.values()) {
-            if (!addSet.containsKey(e.key) || compareTimestamps(addSet.get(e.key), e)) {
-                addSet.put(e.key, e);
-            }
-        }
-
-        for (Element e : other.removeSet.values()) {
-            if (!removeSet.containsKey(e.key) || compareTimestamps(removeSet.get(e.key), e)) {
-                removeSet.put(e.key, e);
-            }
-        }
+    private Element<T> resolveConflict(Element<T> e1, Element<T> e2) {
+        return e1.timestamp.isAfter(e2.timestamp) ? e1 : e2;
     }
+}
+
+/**
+ * Represents an element in the LWWElementSet, consisting of a key and a timestamp. This class is
+ * used to store the elements in both the add and remove sets with their respective timestamps.
+ *
+ * @param <T> The type of the key associated with the element.
+ */
+class Element<T> {
+    T key;
+    Instant timestamp;
 
     /**
-     * Compares timestamps of two elements based on their bias (ADDS or REMOVALS).
+     * Constructs a new Element with the specified key and timestamp.
      *
-     * @param e     The first element.
-     * @param other The second element.
-     * @return True if the first element's timestamp is greater or the bias is ADDS and timestamps are equal.
+     * @param key       The key of the element.
+     * @param timestamp The timestamp associated with the element.
      */
-    public boolean compareTimestamps(Element e, Element other) {
-        if (e.bias != other.bias) {
-            throw new IllegalArgumentException("Invalid bias value");
-        }
-        Bias bias = e.bias;
-        int timestampComparison = Integer.compare(e.timestamp, other.timestamp);
-
-        if (timestampComparison == 0) {
-            return bias != Bias.ADDS;
-        }
-        return timestampComparison < 0;
+    Element(T key, Instant timestamp) {
+        this.key = key;
+        this.timestamp = timestamp;
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java b/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java
index 36593d6669f8..0356949a8f69 100644
--- a/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java
@@ -3,106 +3,96 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.jupiter.api.BeforeEach;
+import java.time.Instant;
 import org.junit.jupiter.api.Test;
 
 class LWWElementSetTest {
 
-    private LWWElementSet set;
-    private final Bias bias = Bias.ADDS;
-
-    @BeforeEach
-    void setUp() {
-        set = new LWWElementSet();
-    }
-
     @Test
-    void testAdd() {
-        Element element = new Element("key1", 1, bias);
-        set.add(element);
-
-        assertTrue(set.lookup(element));
+    void testAddElement() {
+        LWWElementSet<String> set = new LWWElementSet<>();
+        set.add("A");
+        assertTrue(set.lookup("A"));
     }
 
     @Test
-    void testRemove() {
-        Element element = new Element("key1", 1, bias);
-        set.add(element);
-        set.remove(element);
-
-        assertFalse(set.lookup(element));
+    void testRemoveElement() {
+        LWWElementSet<String> set = new LWWElementSet<>();
+        set.add("A");
+        set.remove("A");
+        assertFalse(set.lookup("A"));
     }
 
     @Test
-    void testRemoveNonexistentElement() {
-        Element element = new Element("key1", 1, bias);
-        set.remove(element);
-
-        assertFalse(set.lookup(element));
+    void testLookupWithoutAdding() {
+        LWWElementSet<String> set = new LWWElementSet<>();
+        assertFalse(set.lookup("A"));
     }
 
     @Test
-    void testLookupNonexistentElement() {
-        Element element = new Element("key1", 1, bias);
+    void testLookupLaterTimestampsFalse() {
+        LWWElementSet<String> set = new LWWElementSet<>();
+
+        set.addSet.put("A", new Element<>("A", Instant.now()));
+        set.removeSet.put("A", new Element<>("A", Instant.now().plusSeconds(10)));
 
-        assertFalse(set.lookup(element));
+        assertFalse(set.lookup("A"));
     }
 
     @Test
-    void testCompareEqualSets() {
-        LWWElementSet otherSet = new LWWElementSet();
+    void testLookupEarlierTimestampsTrue() {
+        LWWElementSet<String> set = new LWWElementSet<>();
 
-        Element element = new Element("key1", 1, bias);
-        set.add(element);
-        otherSet.add(element);
+        set.addSet.put("A", new Element<>("A", Instant.now()));
+        set.removeSet.put("A", new Element<>("A", Instant.now().minusSeconds(10)));
 
-        assertTrue(set.compare(otherSet));
-
-        otherSet.add(new Element("key2", 2, bias));
-        assertTrue(set.compare(otherSet));
+        assertTrue(set.lookup("A"));
     }
 
     @Test
-    void testCompareDifferentSets() {
-        LWWElementSet otherSet = new LWWElementSet();
-
-        Element element1 = new Element("key1", 1, bias);
-        Element element2 = new Element("key2", 2, bias);
-
-        set.add(element1);
-        otherSet.add(element2);
-
-        assertFalse(set.compare(otherSet));
+    void testLookupWithConcurrentTimestamps() {
+        LWWElementSet<String> set = new LWWElementSet<>();
+        Instant now = Instant.now();
+        set.addSet.put("A", new Element<>("A", now));
+        set.removeSet.put("A", new Element<>("A", now));
+        assertFalse(set.lookup("A"));
     }
 
     @Test
-    void testMerge() {
-        LWWElementSet otherSet = new LWWElementSet();
+    void testMergeTwoSets() {
+        LWWElementSet<String> set1 = new LWWElementSet<>();
+        LWWElementSet<String> set2 = new LWWElementSet<>();
 
-        Element element1 = new Element("key1", 1, bias);
-        Element element2 = new Element("key2", 2, bias);
+        set1.add("A");
+        set2.add("B");
+        set2.remove("A");
 
-        set.add(element1);
-        otherSet.add(element2);
+        set1.merge(set2);
 
-        set.merge(otherSet);
-
-        assertTrue(set.lookup(element1));
-        assertTrue(set.lookup(element2));
+        assertFalse(set1.lookup("A"));
+        assertTrue(set1.lookup("B"));
     }
 
     @Test
-    void testCompareTimestampsEqualTimestamps() {
-        LWWElementSet lwwElementSet = new LWWElementSet();
+    void testMergeWithConflictingTimestamps() {
+        LWWElementSet<String> set1 = new LWWElementSet<>();
+        LWWElementSet<String> set2 = new LWWElementSet<>();
 
-        Element e1 = new Element("key1", 10, Bias.REMOVALS);
-        Element e2 = new Element("key1", 10, Bias.REMOVALS);
+        Instant now = Instant.now();
+        set1.addSet.put("A", new Element<>("A", now.minusSeconds(10)));
+        set2.addSet.put("A", new Element<>("A", now));
 
-        assertTrue(lwwElementSet.compareTimestamps(e1, e2));
+        set1.merge(set2);
 
-        e1 = new Element("key1", 10, Bias.ADDS);
-        e2 = new Element("key1", 10, Bias.ADDS);
+        assertTrue(set1.lookup("A"));
+    }
 
-        assertFalse(lwwElementSet.compareTimestamps(e1, e2));
+    @Test
+    void testRemoveOlderThanAdd() {
+        LWWElementSet<String> set = new LWWElementSet<>();
+        Instant now = Instant.now();
+        set.addSet.put("A", new Element<>("A", now));
+        set.removeSet.put("A", new Element<>("A", now.minusSeconds(10)));
+        assertTrue(set.lookup("A"));
     }
 }

From 5be5e35d2d1f2915e47da4bf8d0b41f4962d3c4d Mon Sep 17 00:00:00 2001
From: Nithin U <106614289+NithinU2802@users.noreply.github.com>
Date: Mon, 17 Feb 2025 20:25:06 +0530
Subject: [PATCH 0756/1338] Add Heavy-Light Decomposition (HLD) (#6169)

---
 DIRECTORY.md                                  |   4 +
 .../tree/HeavyLightDecomposition.java         | 157 ++++++++++++++++++
 .../tree/HeavyLightDecompositionTest.java     |  69 ++++++++
 3 files changed, 230 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java
 create mode 100644 src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6ccaf0b38e7f..009de2044421 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -723,6 +723,8 @@
             * [WordLadder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/WordLadder.java)
             * zigZagPattern
               * [ZigZagPattern](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java)
+          * tree
+            * [HeavyLightDecomposition](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/tree/HeavyLightDecomposition.java)
   * test
     * java
       * com
@@ -1367,3 +1369,5 @@
             * [WordLadderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/WordLadderTest.java)
             * zigZagPattern
               * [ZigZagPatternTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java)
+          * tree
+            * [HeavyLightDecompositionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java)
diff --git a/src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java b/src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java
new file mode 100644
index 000000000000..236a23205180
--- /dev/null
+++ b/src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java
@@ -0,0 +1,157 @@
+package com.thealgorithms.tree;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Heavy-Light Decomposition (HLD) implementation in Java.
+ * HLD is used to efficiently handle path queries on trees, such as maximum,
+ * sum, or updates. It decomposes the tree into heavy and light chains,
+ * enabling queries in O(log N) time.
+ * Wikipedia Reference: https://en.wikipedia.org/wiki/Heavy-light_decomposition
+ * Author: Nithin U.
+ * Github: https://github.com/NithinU2802
+ */
+
+public class HeavyLightDecomposition {
+    private List<List<Integer>> tree;
+    private int[] parent;
+    private int[] depth;
+    private int[] subtreeSize;
+    private int[] chainHead;
+    private int[] position;
+    private int[] nodeValue;
+    private int[] segmentTree;
+    private int positionIndex;
+
+    public HeavyLightDecomposition(int n) {
+        tree = new ArrayList<>();
+        for (int i = 0; i <= n; i++) {
+            tree.add(new ArrayList<>());
+        }
+        parent = new int[n + 1];
+        depth = new int[n + 1];
+        subtreeSize = new int[n + 1];
+        chainHead = new int[n + 1];
+        position = new int[n + 1];
+        nodeValue = new int[n + 1];
+        segmentTree = new int[4 * (n + 1)];
+        for (int i = 0; i <= n; i++) {
+            chainHead[i] = -1;
+        }
+        positionIndex = 0;
+    }
+
+    public int getPosition(int index) {
+        return position[index];
+    }
+
+    public int getPositionIndex() {
+        return positionIndex;
+    }
+
+    public void addEdge(int u, int v) {
+        tree.get(u).add(v);
+        tree.get(v).add(u);
+    }
+
+    private void dfsSize(int node, int parentNode) {
+        parent[node] = parentNode;
+        subtreeSize[node] = 1;
+        for (int child : tree.get(node)) {
+            if (child != parentNode) {
+                depth[child] = depth[node] + 1;
+                dfsSize(child, node);
+                subtreeSize[node] += subtreeSize[child];
+            }
+        }
+    }
+
+    private void decompose(int node, int head) {
+        chainHead[node] = head;
+        position[node] = positionIndex++;
+        int heavyChild = -1;
+        int maxSubtreeSize = -1;
+        for (int child : tree.get(node)) {
+            if (child != parent[node] && subtreeSize[child] > maxSubtreeSize) {
+                heavyChild = child;
+                maxSubtreeSize = subtreeSize[child];
+            }
+        }
+        if (heavyChild != -1) {
+            decompose(heavyChild, head);
+        }
+        for (int child : tree.get(node)) {
+            if (child != parent[node] && child != heavyChild) {
+                decompose(child, child);
+            }
+        }
+    }
+
+    private void buildSegmentTree(int node, int start, int end) {
+        if (start == end) {
+            segmentTree[node] = nodeValue[start];
+            return;
+        }
+        int mid = (start + end) / 2;
+        buildSegmentTree(2 * node, start, mid);
+        buildSegmentTree(2 * node + 1, mid + 1, end);
+        segmentTree[node] = Math.max(segmentTree[2 * node], segmentTree[2 * node + 1]);
+    }
+
+    public void updateSegmentTree(int node, int start, int end, int index, int value) {
+        if (start == end) {
+            segmentTree[node] = value;
+            return;
+        }
+        int mid = (start + end) / 2;
+        if (index <= mid) {
+            updateSegmentTree(2 * node, start, mid, index, value);
+        } else {
+            updateSegmentTree(2 * node + 1, mid + 1, end, index, value);
+        }
+        segmentTree[node] = Math.max(segmentTree[2 * node], segmentTree[2 * node + 1]);
+    }
+
+    public int querySegmentTree(int node, int start, int end, int left, int right) {
+        if (left > end || right < start) {
+            return Integer.MIN_VALUE;
+        }
+        if (left <= start && end <= right) {
+            return segmentTree[node];
+        }
+        int mid = (start + end) / 2;
+        int leftQuery = querySegmentTree(2 * node, start, mid, left, right);
+        int rightQuery = querySegmentTree(2 * node + 1, mid + 1, end, left, right);
+        return Math.max(leftQuery, rightQuery);
+    }
+
+    public int queryMaxInPath(int u, int v) {
+        int result = Integer.MIN_VALUE;
+        while (chainHead[u] != chainHead[v]) {
+            if (depth[chainHead[u]] < depth[chainHead[v]]) {
+                int temp = u;
+                u = v;
+                v = temp;
+            }
+            result = Math.max(result, querySegmentTree(1, 0, positionIndex - 1, position[chainHead[u]], position[u]));
+            u = parent[chainHead[u]];
+        }
+        if (depth[u] > depth[v]) {
+            int temp = u;
+            u = v;
+            v = temp;
+        }
+        result = Math.max(result, querySegmentTree(1, 0, positionIndex - 1, position[u], position[v]));
+        return result;
+    }
+
+    public void initialize(int root, int[] values) {
+        dfsSize(root, -1);
+        decompose(root, root);
+        for (int i = 0; i < values.length; i++) {
+            nodeValue[position[i]] = values[i];
+        }
+        buildSegmentTree(1, 0, positionIndex - 1);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java b/src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java
new file mode 100644
index 000000000000..29189290e1d4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.tree;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class HeavyLightDecompositionTest {
+
+    private HeavyLightDecomposition hld;
+    private final int[] values = {0, 10, 20, 30, 40, 50};
+
+    /**
+     * Initializes the test environment with a predefined tree structure and values.
+     */
+    @BeforeEach
+    void setUp() {
+        hld = new HeavyLightDecomposition(5);
+        hld.addEdge(1, 2);
+        hld.addEdge(1, 3);
+        hld.addEdge(2, 4);
+        hld.addEdge(2, 5);
+        hld.initialize(1, values);
+    }
+
+    /**
+     * Verifies that the tree initializes successfully without errors.
+     */
+    @Test
+    void testBasicTreeInitialization() {
+        assertTrue(true, "Basic tree structure initialized successfully");
+    }
+
+    /**
+     * Tests the maximum value query in the path between nodes.
+     */
+    @Test
+    void testQueryMaxInPath() {
+        assertEquals(50, hld.queryMaxInPath(4, 5), "Max value in path (4,5) should be 50");
+        assertEquals(30, hld.queryMaxInPath(3, 2), "Max value in path (3,2) should be 30");
+    }
+
+    /**
+     * Tests updating a node's value and ensuring it is reflected in queries.
+     */
+    @Test
+    void testUpdateNodeValue() {
+        hld.updateSegmentTree(1, 0, hld.getPositionIndex() - 1, hld.getPosition(4), 100);
+        assertEquals(100, hld.queryMaxInPath(4, 5), "Updated value should be reflected in query");
+    }
+
+    /**
+     * Tests the maximum value query in a skewed tree structure.
+     */
+    @Test
+    void testSkewedTreeMaxQuery() {
+        assertEquals(40, hld.queryMaxInPath(1, 4), "Max value in skewed tree (1,4) should be 40");
+    }
+
+    /**
+     * Ensures query handles cases where u is a deeper node correctly.
+     */
+    @Test
+    void testDepthSwapInPathQuery() {
+        assertEquals(50, hld.queryMaxInPath(5, 2), "Query should handle depth swap correctly");
+        assertEquals(40, hld.queryMaxInPath(4, 1), "Query should handle swapped nodes correctly and return max value");
+    }
+}

From 1f951c1ed5dbd43e9ced6245df55740946a741de Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 17 Feb 2025 23:42:16 +0100
Subject: [PATCH 0757/1338] Bump com.github.spotbugs:spotbugs-maven-plugin from
 4.8.6.6 to 4.9.1.0 (#6171)

* Bump com.github.spotbugs:spotbugs-maven-plugin from 4.8.6.6 to 4.9.1.0

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.8.6.6 to 4.9.1.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.8.6.6...spotbugs-maven-plugin-4.9.1.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* fix: suppress `AT_STALE_THREAD_WRITE_OF_PRIMITIVE`

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 pom.xml              | 2 +-
 spotbugs-exclude.xml | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 7900c6f2d956..4c17a883ec24 100644
--- a/pom.xml
+++ b/pom.xml
@@ -132,7 +132,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.8.6.6</version>
+                <version>4.9.1.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index d3eff458ea45..3b77ced1a13e 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -83,6 +83,9 @@
     <Match>
         <Bug pattern="RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE" />
     </Match>
+    <Match>
+        <Bug pattern="AT_STALE_THREAD_WRITE_OF_PRIMITIVE" />
+    </Match>
     <!-- fb-contrib -->
     <Match>
         <Bug pattern="LSC_LITERAL_STRING_COMPARISON" />

From ed3680b8807853947b2e1b913fc4e9055b8335db Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 22 Feb 2025 00:11:43 +0100
Subject: [PATCH 0758/1338] Bump org.apache.maven.plugins:maven-compiler-plugin
 from 3.13.0 to 3.14.0 (#6175)

Bump org.apache.maven.plugins:maven-compiler-plugin

Bumps [org.apache.maven.plugins:maven-compiler-plugin](https://github.com/apache/maven-compiler-plugin) from 3.13.0 to 3.14.0.
- [Release notes](https://github.com/apache/maven-compiler-plugin/releases)
- [Commits](https://github.com/apache/maven-compiler-plugin/compare/maven-compiler-plugin-3.13.0...maven-compiler-plugin-3.14.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-compiler-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 4c17a883ec24..e5357dec7e36 100644
--- a/pom.xml
+++ b/pom.xml
@@ -78,7 +78,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.13.0</version>
+                <version>3.14.0</version>
                 <configuration>
                     <source>21</source>
                     <target>21</target>

From bb0bb03b62021ade7c15224440accb4ceeb3feb0 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 22 Feb 2025 19:52:33 +0100
Subject: [PATCH 0759/1338] Bump org.junit.jupiter:junit-jupiter from 5.11.4 to
 5.12.0 (#6176)

Bumps [org.junit.jupiter:junit-jupiter](https://github.com/junit-team/junit5) from 5.11.4 to 5.12.0.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.4...r5.12.0)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index e5357dec7e36..125ea68e2a0f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.11.4</version>
+            <version>5.12.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From f40330c553f52ec8f508ff5d959f76a5e452ce96 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 22 Feb 2025 21:09:28 +0100
Subject: [PATCH 0760/1338] chore: use BOM to manage junit dependencies (#6178)

---
 pom.xml | 2 --
 1 file changed, 2 deletions(-)

diff --git a/pom.xml b/pom.xml
index 125ea68e2a0f..20339583c606 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,6 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.12.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -51,7 +50,6 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>5.11.4</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 27bbc3e8101e5fe08ef88c5b53b5102289aadf43 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 22 Feb 2025 20:13:39 +0000
Subject: [PATCH 0761/1338] Bump org.junit:junit-bom from 5.11.4 to 5.12.0
 (#6174)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.11.4 to 5.12.0.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.11.4...r5.12.0)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 20339583c606..ab8a5b5ab879 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.11.4</version>
+                <version>5.12.0</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 9ce2ff4865f12ec3b98cf7a35abb04d5e8d5f969 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 24 Feb 2025 14:04:17 +0100
Subject: [PATCH 0762/1338] chore: remove explicit dependency to
 `junit-jupiter-api` (#6179)

---
 pom.xml | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/pom.xml b/pom.xml
index ab8a5b5ab879..dc16d16d1b3f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -45,13 +45,6 @@
             <version>5.15.2</version>
             <scope>test</scope>
         </dependency>
-
-
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter-api</artifactId>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>

From df6da475e2400bbf5f8d768e4ffbb85fabd95e3a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 24 Feb 2025 23:02:54 +0100
Subject: [PATCH 0763/1338] Bump com.puppycrawl.tools:checkstyle from 10.21.2
 to 10.21.3 (#6181)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.21.2 to 10.21.3.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.21.2...checkstyle-10.21.3)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index dc16d16d1b3f..ede44194ca16 100644
--- a/pom.xml
+++ b/pom.xml
@@ -116,7 +116,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.21.2</version>
+                    <version>10.21.3</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 849ab913c0d22c7d1df967b6e46eea849f3dab42 Mon Sep 17 00:00:00 2001
From: geetoormvn <52828564+geetoor-maven@users.noreply.github.com>
Date: Thu, 27 Feb 2025 17:45:52 +0700
Subject: [PATCH 0764/1338] Add reverseUsingStringBuilder method to reverse a
 string (#6182)

---
 .../thealgorithms/strings/ReverseString.java  | 21 +++++++++++++++++++
 .../strings/ReverseStringTest.java            |  6 ++++++
 2 files changed, 27 insertions(+)

diff --git a/src/main/java/com/thealgorithms/strings/ReverseString.java b/src/main/java/com/thealgorithms/strings/ReverseString.java
index 46a0494fcbb4..54a9b779e828 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseString.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseString.java
@@ -36,4 +36,25 @@ public static String reverse2(String str) {
         }
         return new String(value);
     }
+
+    /**
+     * Reverse version 3 the given string using a StringBuilder.
+     * This method converts the string to a character array,
+     * iterates through it in reverse order, and appends each character
+     * to a StringBuilder.
+     *
+     * @param string The input string to be reversed.
+     * @return The reversed string.
+     */
+    public static String reverse3(String string) {
+        if (string.isEmpty()) {
+            return string;
+        }
+        char[] chars = string.toCharArray();
+        StringBuilder sb = new StringBuilder();
+        for (int i = string.length() - 1; i >= 0; i--) {
+            sb.append(chars[i]);
+        }
+        return sb.toString();
+    }
 }
diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
index 501f702976ec..08f5fb586d82 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
@@ -25,4 +25,10 @@ public void testReverseString(String input, String expectedOutput) {
     public void testReverseString2(String input, String expectedOutput) {
         assertEquals(expectedOutput, ReverseString.reverse2(input));
     }
+
+    @ParameterizedTest
+    @MethodSource("testCases")
+    public void testReverseString3(String input, String expectedOutput) {
+        assertEquals(expectedOutput, ReverseString.reverse3(input));
+    }
 }

From c8281e02fbb01ab2c02170aa15337315a70ef0ab Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Sat, 1 Mar 2025 09:52:06 +0100
Subject: [PATCH 0765/1338] Add Maximum Weighted Matching Algorithm for Trees
 (#6184)

---
 .../graphs/UndirectedAdjacencyListGraph.java  |  69 ++++++++++
 .../dynamicprogramming/TreeMatching.java      |  78 ++++++++++++
 .../dynamicprogramming/TreeMatchingTest.java  | 120 ++++++++++++++++++
 3 files changed, 267 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/UndirectedAdjacencyListGraph.java
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/TreeMatching.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/TreeMatchingTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/UndirectedAdjacencyListGraph.java b/src/main/java/com/thealgorithms/datastructures/graphs/UndirectedAdjacencyListGraph.java
new file mode 100644
index 000000000000..8aafc1ef3368
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/UndirectedAdjacencyListGraph.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+
+public class UndirectedAdjacencyListGraph {
+    private ArrayList<HashMap<Integer, Integer>> adjacencyList = new ArrayList<>();
+
+    /**
+     * Adds a new node to the graph by adding an empty HashMap for its neighbors.
+     * @return the index of the newly added node in the adjacency list
+     */
+    public int addNode() {
+        adjacencyList.add(new HashMap<>());
+        return adjacencyList.size() - 1;
+    }
+
+    /**
+     * Adds an undirected edge between the origin node (@orig) and the destination node (@dest) with the specified weight.
+     * If the edge already exists, no changes are made.
+     * @param orig the index of the origin node
+     * @param dest the index of the destination node
+     * @param weight the weight of the edge between @orig and @dest
+     * @return true if the edge was successfully added, false if the edge already exists or if any node index is invalid
+     */
+    public boolean addEdge(int orig, int dest, int weight) {
+        int numNodes = adjacencyList.size();
+        if (orig >= numNodes || dest >= numNodes || orig < 0 || dest < 0) {
+            return false;
+        }
+
+        if (adjacencyList.get(orig).containsKey(dest)) {
+            return false;
+        }
+
+        adjacencyList.get(orig).put(dest, weight);
+        adjacencyList.get(dest).put(orig, weight);
+        return true;
+    }
+
+    /**
+     * Returns the set of all adjacent nodes (neighbors) for the given node.
+     * @param node the index of the node whose neighbors are to be retrieved
+     * @return a HashSet containing the indices of all neighboring nodes
+     */
+    public HashSet<Integer> getNeighbors(int node) {
+        return new HashSet<>(adjacencyList.get(node).keySet());
+    }
+
+    /**
+     * Returns the weight of the edge between the origin node (@orig) and the destination node (@dest).
+     * If no edge exists, returns null.
+     * @param orig the index of the origin node
+     * @param dest the index of the destination node
+     * @return the weight of the edge between @orig and @dest, or null if no edge exists
+     */
+    public Integer getEdgeWeight(int orig, int dest) {
+        return adjacencyList.get(orig).getOrDefault(dest, null);
+    }
+
+    /**
+     * Returns the number of nodes currently in the graph.
+     * @return the number of nodes in the graph
+     */
+    public int size() {
+        return adjacencyList.size();
+    }
+}
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/TreeMatching.java b/src/main/java/com/thealgorithms/dynamicprogramming/TreeMatching.java
new file mode 100644
index 000000000000..9fd82ccaf078
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/TreeMatching.java
@@ -0,0 +1,78 @@
+package com.thealgorithms.dynamicprogramming;
+
+import com.thealgorithms.datastructures.graphs.UndirectedAdjacencyListGraph;
+
+/**
+ * This class implements the algorithm for calculating the maximum weighted matching in a tree.
+ * The tree is represented as an undirected graph with weighted edges.
+ *
+ * Problem Description:
+ *  Given an undirected tree G = (V, E) with edge weights γ: E → N and a root r ∈ V,
+ *  the goal is to find a maximum weight matching M ⊆ E such that no two edges in M
+ *  share a common vertex. The sum of the weights of the edges in M, ∑ e∈M γ(e), should be maximized.
+ *  For more Information: <a href="https://en.wikipedia.org/wiki/Matching_(graph_theory)">Matching (graph theory)</a>
+ *
+ * @author  <a href="https://github.com/DenizAltunkapan">Deniz Altunkapan</a>
+ */
+public class TreeMatching {
+
+    private UndirectedAdjacencyListGraph graph;
+    private int[][] dp;
+
+    /**
+     * Constructor that initializes the graph and the DP table.
+     *
+     * @param graph The graph that represents the tree and is used for the matching algorithm.
+     */
+    public TreeMatching(UndirectedAdjacencyListGraph graph) {
+        this.graph = graph;
+        this.dp = new int[graph.size()][2];
+    }
+
+    /**
+     * Calculates the maximum weighted matching for the tree, starting from the given root node.
+     *
+     * @param root The index of the root node of the tree.
+     * @param parent The index of the parent node (used for recursion).
+     * @return The maximum weighted matching for the tree, starting from the root node.
+     *
+     */
+    public int getMaxMatching(int root, int parent) {
+        if (root < 0 || root >= graph.size()) {
+            throw new IllegalArgumentException("Invalid root: " + root);
+        }
+        maxMatching(root, parent);
+        return Math.max(dp[root][0], dp[root][1]);
+    }
+
+    /**
+     * Recursively computes the maximum weighted matching for a node, assuming that the node
+     * can either be included or excluded from the matching.
+     *
+     * @param node The index of the current node for which the matching is calculated.
+     * @param parent The index of the parent node (to avoid revisiting the parent node during recursion).
+     */
+    private void maxMatching(int node, int parent) {
+        dp[node][0] = 0;
+        dp[node][1] = 0;
+
+        int sumWithoutEdge = 0;
+        for (int adjNode : graph.getNeighbors(node)) {
+            if (adjNode == parent) {
+                continue;
+            }
+            maxMatching(adjNode, node);
+            sumWithoutEdge += Math.max(dp[adjNode][0], dp[adjNode][1]);
+        }
+
+        dp[node][0] = sumWithoutEdge;
+
+        for (int adjNode : graph.getNeighbors(node)) {
+            if (adjNode == parent) {
+                continue;
+            }
+            int weight = graph.getEdgeWeight(node, adjNode);
+            dp[node][1] = Math.max(dp[node][1], sumWithoutEdge - Math.max(dp[adjNode][0], dp[adjNode][1]) + dp[adjNode][0] + weight);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/TreeMatchingTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/TreeMatchingTest.java
new file mode 100644
index 000000000000..d5418770a5d1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/TreeMatchingTest.java
@@ -0,0 +1,120 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.thealgorithms.datastructures.graphs.UndirectedAdjacencyListGraph;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class TreeMatchingTest {
+    UndirectedAdjacencyListGraph graph;
+
+    @BeforeEach
+    void setUp() {
+        graph = new UndirectedAdjacencyListGraph();
+        for (int i = 0; i < 14; i++) {
+            graph.addNode();
+        }
+    }
+
+    @Test
+    void testMaxMatchingForGeneralTree() {
+        graph.addEdge(0, 1, 20);
+        graph.addEdge(0, 2, 30);
+        graph.addEdge(1, 3, 40);
+        graph.addEdge(1, 4, 10);
+        graph.addEdge(2, 5, 20);
+        graph.addEdge(3, 6, 30);
+        graph.addEdge(3, 7, 30);
+        graph.addEdge(5, 8, 40);
+        graph.addEdge(5, 9, 10);
+
+        TreeMatching treeMatching = new TreeMatching(graph);
+        assertEquals(110, treeMatching.getMaxMatching(0, -1));
+    }
+
+    @Test
+    void testMaxMatchingForBalancedTree() {
+        graph.addEdge(0, 1, 20);
+        graph.addEdge(0, 2, 30);
+        graph.addEdge(0, 3, 40);
+        graph.addEdge(1, 4, 10);
+        graph.addEdge(1, 5, 20);
+        graph.addEdge(2, 6, 20);
+        graph.addEdge(3, 7, 30);
+        graph.addEdge(5, 8, 10);
+        graph.addEdge(5, 9, 20);
+        graph.addEdge(7, 10, 10);
+        graph.addEdge(7, 11, 10);
+        graph.addEdge(7, 12, 5);
+        TreeMatching treeMatching = new TreeMatching(graph);
+        assertEquals(100, treeMatching.getMaxMatching(0, -1));
+    }
+
+    @Test
+    void testMaxMatchingForTreeWithVariedEdgeWeights() {
+        graph.addEdge(0, 1, 20);
+        graph.addEdge(0, 2, 30);
+        graph.addEdge(0, 3, 40);
+        graph.addEdge(0, 4, 50);
+        graph.addEdge(1, 5, 20);
+        graph.addEdge(2, 6, 20);
+        graph.addEdge(3, 7, 30);
+        graph.addEdge(5, 8, 10);
+        graph.addEdge(5, 9, 20);
+        graph.addEdge(7, 10, 10);
+        graph.addEdge(4, 11, 50);
+        graph.addEdge(4, 12, 20);
+        TreeMatching treeMatching = new TreeMatching(graph);
+        assertEquals(140, treeMatching.getMaxMatching(0, -1));
+    }
+
+    @Test
+    void emptyTree() {
+        TreeMatching treeMatching = new TreeMatching(graph);
+        assertEquals(0, treeMatching.getMaxMatching(0, -1));
+    }
+
+    @Test
+    void testSingleNodeTree() {
+        UndirectedAdjacencyListGraph singleNodeGraph = new UndirectedAdjacencyListGraph();
+        singleNodeGraph.addNode();
+
+        TreeMatching treeMatching = new TreeMatching(singleNodeGraph);
+        assertEquals(0, treeMatching.getMaxMatching(0, -1));
+    }
+
+    @Test
+    void testLinearTree() {
+        graph.addEdge(0, 1, 10);
+        graph.addEdge(1, 2, 20);
+        graph.addEdge(2, 3, 30);
+        graph.addEdge(3, 4, 40);
+
+        TreeMatching treeMatching = new TreeMatching(graph);
+        assertEquals(60, treeMatching.getMaxMatching(0, -1));
+    }
+
+    @Test
+    void testStarShapedTree() {
+        graph.addEdge(0, 1, 15);
+        graph.addEdge(0, 2, 25);
+        graph.addEdge(0, 3, 35);
+        graph.addEdge(0, 4, 45);
+
+        TreeMatching treeMatching = new TreeMatching(graph);
+        assertEquals(45, treeMatching.getMaxMatching(0, -1));
+    }
+
+    @Test
+    void testUnbalancedTree() {
+        graph.addEdge(0, 1, 10);
+        graph.addEdge(0, 2, 20);
+        graph.addEdge(1, 3, 30);
+        graph.addEdge(2, 4, 40);
+        graph.addEdge(4, 5, 50);
+
+        TreeMatching treeMatching = new TreeMatching(graph);
+        assertEquals(100, treeMatching.getMaxMatching(0, -1));
+    }
+}

From f70a2187aceca41327bdfff8c4b8e09096730bce Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 4 Mar 2025 00:37:02 +0100
Subject: [PATCH 0766/1338] Bump org.mockito:mockito-core from 5.15.2 to 5.16.0
 (#6185)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.15.2 to 5.16.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.15.2...v5.16.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index ede44194ca16..374129ed2b8f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.15.2</version>
+            <version>5.16.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From b2a701a67991b39a073684e118e2144b08591319 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 5 Mar 2025 00:01:18 +0100
Subject: [PATCH 0767/1338] Bump com.puppycrawl.tools:checkstyle from 10.21.3
 to 10.21.4 (#6187)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.21.3 to 10.21.4.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.21.3...checkstyle-10.21.4)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 374129ed2b8f..0f9ab7456452 100644
--- a/pom.xml
+++ b/pom.xml
@@ -116,7 +116,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.21.3</version>
+                    <version>10.21.4</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 9bfc05ad8d1e4449e9c3fc9cd10320e043f8506f Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 4 Mar 2025 23:05:12 +0000
Subject: [PATCH 0768/1338] Bump com.github.spotbugs:spotbugs-maven-plugin from
 4.9.1.0 to 4.9.2.0 (#6188)

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.1.0 to 4.9.2.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.1.0...spotbugs-maven-plugin-4.9.2.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 0f9ab7456452..04073aef3d90 100644
--- a/pom.xml
+++ b/pom.xml
@@ -123,7 +123,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.1.0</version>
+                <version>4.9.2.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From e6073f8fefa7f1b63a9170ac56712f04469c5442 Mon Sep 17 00:00:00 2001
From: Hakim's Garage <92100853+sadiul-hakim@users.noreply.github.com>
Date: Wed, 12 Mar 2025 22:35:21 +0600
Subject: [PATCH 0769/1338] Add math builder (#6190)

---
 DIRECTORY.md                                  |   9 +-
 .../com/thealgorithms/maths/MathBuilder.java  | 345 ++++++++++++++++++
 .../matrix/PrintAMatrixInSpiralOrder.java     |   9 -
 .../others/PrintAMatrixInSpiralOrder.java     |  52 +++
 .../SearchInARowAndColWiseSortedMatrix.java   |   1 -
 .../thealgorithms/maths/MathBuilderTest.java  |  38 ++
 .../others/TestPrintMatrixInSpiralOrder.java  |  26 ++
 ...estSearchInARowAndColWiseSortedMatrix.java |  52 ++-
 8 files changed, 494 insertions(+), 38 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/maths/MathBuilder.java
 create mode 100644 src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java
 create mode 100644 src/test/java/com/thealgorithms/maths/MathBuilderTest.java
 create mode 100644 src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 009de2044421..f53a6220c517 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -162,6 +162,7 @@
               * [MatrixGraphs](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java)
               * [PrimMST](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java)
               * [TarjansAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java)
+              * [UndirectedAdjacencyListGraph](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/UndirectedAdjacencyListGraph.java)
               * [WelshPowell](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java)
             * hashmap
               * hashing
@@ -319,6 +320,7 @@
             * [SubsetSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java)
             * [SubsetSumSpaceOptimized](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java)
             * [SumOfSubset](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java)
+            * [TreeMatching](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/TreeMatching.java)
             * [Tribonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java)
             * [UniquePaths](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java)
             * [UniqueSubsequencesCount](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCount.java)
@@ -423,6 +425,7 @@
             * [LongDivision](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LongDivision.java)
             * [LucasSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LucasSeries.java)
             * [MagicSquare](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MagicSquare.java)
+            * [MathBuilder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MathBuilder.java)
             * [MaxValue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MaxValue.java)
             * [Means](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Means.java)
             * [Median](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Median.java)
@@ -537,6 +540,7 @@
             * [PageRank](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PageRank.java)
             * [PasswordGen](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PasswordGen.java)
             * [PerlinNoise](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PerlinNoise.java)
+            * [PrintAMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java)
             * [QueueUsingTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java)
             * [RemoveDuplicateFromString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java)
             * [ReverseStackUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
@@ -724,7 +728,7 @@
             * zigZagPattern
               * [ZigZagPattern](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java)
           * tree
-            * [HeavyLightDecomposition](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/tree/HeavyLightDecomposition.java)
+            * [HeavyLightDecomposition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java)
   * test
     * java
       * com
@@ -1003,6 +1007,7 @@
             * [SubsetSumSpaceOptimizedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimizedTest.java)
             * [SubsetSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java)
             * [SumOfSubsetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java)
+            * [TreeMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/TreeMatchingTest.java)
             * [TribonacciTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java)
             * [UniquePathsTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java)
             * [UniqueSubsequencesCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCountTest.java)
@@ -1097,6 +1102,7 @@
             * [LeonardoNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java)
             * [LongDivisionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LongDivisionTest.java)
             * [LucasSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LucasSeriesTest.java)
+            * [MathBuilderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MathBuilderTest.java)
             * [MaxValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MaxValueTest.java)
             * [MeansTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MeansTest.java)
             * [MedianTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MedianTest.java)
@@ -1190,6 +1196,7 @@
             * [RemoveDuplicateFromStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java)
             * [ReverseStackUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
             * [SkylineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
+            * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
           * puzzlesandgames
diff --git a/src/main/java/com/thealgorithms/maths/MathBuilder.java b/src/main/java/com/thealgorithms/maths/MathBuilder.java
new file mode 100644
index 000000000000..3534749dd41c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/MathBuilder.java
@@ -0,0 +1,345 @@
+package com.thealgorithms.maths;
+
+import java.text.DecimalFormat;
+import java.util.Random;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+/**
+ * Author: Sadiul Hakim : https://github.com/sadiul-hakim
+ * Profession: Backend Engineer
+ * Date: Oct 20, 2024
+ */
+public final class MathBuilder {
+    private final double result;
+
+    private MathBuilder(Builder builder) {
+        this.result = builder.number;
+    }
+
+    // Returns final result
+    public double get() {
+        return result;
+    }
+
+    // Return result in long
+    public long toLong() {
+        try {
+            if (Double.isNaN(result)) {
+                throw new IllegalArgumentException("Cannot convert NaN to long");
+            }
+            if (result == Double.POSITIVE_INFINITY) {
+                return Long.MAX_VALUE;
+            }
+            if (result == Double.NEGATIVE_INFINITY) {
+                return Long.MIN_VALUE;
+            }
+            if (result > Long.MAX_VALUE) {
+                return Long.MAX_VALUE;
+            }
+            if (result < Long.MIN_VALUE) {
+                return Long.MIN_VALUE;
+            }
+            return Math.round(result);
+        } catch (Exception ex) {
+            return 0;
+        }
+    }
+
+    public static class Builder {
+        private double number;
+        private double memory = 0;
+
+        public Builder() {
+            number = 0;
+        }
+
+        public Builder(double num) {
+            number = num;
+        }
+
+        public Builder add(double num) {
+            number += num;
+            return this;
+        }
+
+        // Takes a number and a condition, only does the operation if condition is true.
+        public Builder addIf(double num, BiFunction<Double, Double, Boolean> condition) {
+            if (condition.apply(number, num)) {
+                number += num;
+            }
+            return this;
+        }
+
+        public Builder minus(double num) {
+            number -= num;
+            return this;
+        }
+
+        // Takes a number and a condition, only does the operation if condition is true.
+        public Builder minusIf(double num, BiFunction<Double, Double, Boolean> condition) {
+            if (condition.apply(number, num)) {
+                number -= num;
+            }
+            return this;
+        }
+
+        // Generates a random number and sets to NUMBER
+        public Builder rand(long seed) {
+            if (number != 0) {
+                throw new RuntimeException("Number must be zero for random assignment!");
+            }
+            Random random = new Random();
+            number = random.nextDouble(seed);
+            return this;
+        }
+
+        // Takes PI value and sets to NUMBER
+        public Builder pi() {
+            if (number != 0) {
+                throw new RuntimeException("Number must be zero for PI assignment!");
+            }
+            number = Math.PI;
+            return this;
+        }
+
+        // Takes E value and sets to NUMBER
+        public Builder e() {
+            if (number != 0) {
+                throw new RuntimeException("Number must be zero for E assignment!");
+            }
+            number = Math.E;
+            return this;
+        }
+
+        public Builder randomInRange(double min, double max) {
+
+            if (number != 0) {
+                throw new RuntimeException("Number must be zero for random assignment!");
+            }
+            Random random = new Random();
+            number = min + (max - min) * random.nextDouble();
+            return this;
+        }
+
+        public Builder toDegrees() {
+            number = Math.toDegrees(number);
+            return this;
+        }
+
+        public Builder max(double num) {
+            number = Math.max(number, num);
+            return this;
+        }
+
+        public Builder min(double num) {
+            number = Math.min(number, num);
+            return this;
+        }
+
+        public Builder multiply(double num) {
+            number *= num;
+            return this;
+        }
+
+        // Takes a number and a condition, only does the operation if condition is true.
+        public Builder multiplyIf(double num, BiFunction<Double, Double, Boolean> condition) {
+            if (condition.apply(number, num)) {
+                number *= num;
+            }
+            return this;
+        }
+
+        public Builder divide(double num) {
+            if (num == 0) {
+                return this;
+            }
+            number /= num;
+            return this;
+        }
+
+        // Takes a number and a condition, only does the operation if condition is true.
+        public Builder divideIf(double num, BiFunction<Double, Double, Boolean> condition) {
+            if (num == 0) {
+                return this;
+            }
+            if (condition.apply(number, num)) {
+                number /= num;
+            }
+            return this;
+        }
+
+        public Builder mod(double num) {
+            number %= num;
+            return this;
+        }
+
+        // Takes a number and a condition, only does the operation if condition is true.
+        public Builder modIf(double num, BiFunction<Double, Double, Boolean> condition) {
+            if (condition.apply(number, num)) {
+                number %= num;
+            }
+            return this;
+        }
+
+        public Builder pow(double num) {
+            number = Math.pow(number, num);
+            return this;
+        }
+
+        public Builder sqrt() {
+            number = Math.sqrt(number);
+            return this;
+        }
+
+        public Builder round() {
+            number = Math.round(number);
+            return this;
+        }
+
+        public Builder floor() {
+            number = Math.floor(number);
+            return this;
+        }
+
+        public Builder ceil() {
+            number = Math.ceil(number);
+            return this;
+        }
+
+        public Builder abs() {
+            number = Math.abs(number);
+            return this;
+        }
+
+        public Builder cbrt() {
+            number = Math.cbrt(number);
+            return this;
+        }
+
+        public Builder log() {
+            number = Math.log(number);
+            return this;
+        }
+
+        public Builder log10() {
+            number = Math.log10(number);
+            return this;
+        }
+
+        public Builder sin() {
+            number = Math.sin(number);
+            return this;
+        }
+
+        public Builder cos() {
+            number = Math.cos(number);
+            return this;
+        }
+
+        public Builder tan() {
+            number = Math.tan(number);
+            return this;
+        }
+
+        public Builder sinh() {
+            number = Math.sinh(number);
+            return this;
+        }
+
+        public Builder cosh() {
+            number = Math.cosh(number);
+            return this;
+        }
+
+        public Builder tanh() {
+            number = Math.tanh(number);
+            return this;
+        }
+
+        public Builder exp() {
+            number = Math.exp(number);
+            return this;
+        }
+
+        public Builder toRadians() {
+            number = Math.toRadians(number);
+            return this;
+        }
+
+        // Remembers the NUMBER
+        public Builder remember() {
+            memory = number;
+            return this;
+        }
+
+        // Recalls the NUMBER
+        public Builder recall(boolean cleanMemory) {
+            number = memory;
+            if (cleanMemory) {
+                memory = 0;
+            }
+
+            return this;
+        }
+
+        // Recalls the NUMBER on condition
+        public Builder recallIf(Function<Double, Boolean> condition, boolean cleanMemory) {
+            if (!condition.apply(number)) {
+                return this;
+            }
+            number = memory;
+            if (cleanMemory) {
+                memory = 0;
+            }
+
+            return this;
+        }
+
+        // Replaces NUMBER with given number
+        public Builder set(double num) {
+            if (number != 0) {
+                throw new RuntimeException("Number must be zero to set!");
+            }
+            number = num;
+            return this;
+        }
+
+        // Replaces NUMBER with given number on condition
+        public Builder setIf(double num, BiFunction<Double, Double, Boolean> condition) {
+            if (number != 0) {
+                throw new RuntimeException("Number must be zero to set!");
+            }
+            if (condition.apply(number, num)) {
+                number = num;
+            }
+            return this;
+        }
+
+        // Prints current NUMBER
+        public Builder print() {
+            System.out.println("MathBuilder Result :: " + number);
+            return this;
+        }
+
+        public Builder format(String format) {
+            DecimalFormat formater = new DecimalFormat(format);
+            String num = formater.format(number);
+            number = Double.parseDouble(num);
+            return this;
+        }
+
+        public Builder format(int decimalPlace) {
+            String pattern = "."
+                + "#".repeat(decimalPlace);
+            DecimalFormat formater = new DecimalFormat(pattern);
+            String num = formater.format(number);
+            number = Double.parseDouble(num);
+            return this;
+        }
+
+        public MathBuilder build() {
+            return new MathBuilder(this);
+        }
+    }
+}
diff --git a/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java b/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java
index 2e735222b7a6..2757da1f9023 100644
--- a/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java
+++ b/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java
@@ -12,7 +12,6 @@ public class PrintAMatrixInSpiralOrder {
      * @param col    number of columns matrix has
      * @author Sadiul Hakim : https://github.com/sadiul-hakim
      */
-
     public List<Integer> print(int[][] matrix, int row, int col) {
 
         // r traverses matrix row wise from first
@@ -20,35 +19,27 @@ public List<Integer> print(int[][] matrix, int row, int col) {
         // c traverses matrix column wise from first
         int c = 0;
         int i;
-
         List<Integer> result = new ArrayList<>();
-
         while (r < row && c < col) {
             // print first row of matrix
             for (i = c; i < col; i++) {
                 result.add(matrix[r][i]);
             }
-
             // increase r by one because first row printed
             r++;
-
             // print last column
             for (i = r; i < row; i++) {
                 result.add(matrix[i][col - 1]);
             }
-
             // decrease col by one because last column has been printed
             col--;
-
             // print rows from last except printed elements
             if (r < row) {
                 for (i = col - 1; i >= c; i--) {
                     result.add(matrix[row - 1][i]);
                 }
-
                 row--;
             }
-
             // print columns from first except printed elements
             if (c < col) {
                 for (i = row - 1; i >= r; i--) {
diff --git a/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java b/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java
new file mode 100644
index 000000000000..abfdd006879e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java
@@ -0,0 +1,52 @@
+package com.thealgorithms.others;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class PrintAMatrixInSpiralOrder {
+    /**
+     * Search a key in row and column wise sorted matrix
+     *
+     * @param matrix matrix to be searched
+     * @param row    number of rows matrix has
+     * @param col    number of columns matrix has
+     * @author Sadiul Hakim : https://github.com/sadiul-hakim
+     */
+    public List<Integer> print(int[][] matrix, int row, int col) {
+        // r traverses matrix row wise from first
+        int r = 0;
+        // c traverses matrix column wise from first
+        int c = 0;
+        int i;
+        List<Integer> result = new ArrayList<>();
+        while (r < row && c < col) {
+            // print first row of matrix
+            for (i = c; i < col; i++) {
+                result.add(matrix[r][i]);
+            }
+            // increase r by one because first row printed
+            r++;
+            // print last column
+            for (i = r; i < row; i++) {
+                result.add(matrix[i][col - 1]);
+            }
+            // decrease col by one because last column has been printed
+            col--;
+            // print rows from last except printed elements
+            if (r < row) {
+                for (i = col - 1; i >= c; i--) {
+                    result.add(matrix[row - 1][i]);
+                }
+                row--;
+            }
+            // print columns from first except printed elements
+            if (c < col) {
+                for (i = row - 1; i >= r; i--) {
+                    result.add(matrix[i][c]);
+                }
+                c++;
+            }
+        }
+        return result;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java b/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java
index 91fda373dca7..b53c7e5256ca 100644
--- a/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java
+++ b/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java
@@ -15,7 +15,6 @@ public int[] search(int[][] matrix, int value) {
         // This variable iterates over columns
         int j = n - 1;
         int[] result = {-1, -1};
-
         while (i < n && j >= 0) {
             if (matrix[i][j] == value) {
                 result[0] = i;
diff --git a/src/test/java/com/thealgorithms/maths/MathBuilderTest.java b/src/test/java/com/thealgorithms/maths/MathBuilderTest.java
new file mode 100644
index 000000000000..b6ecc6746701
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/MathBuilderTest.java
@@ -0,0 +1,38 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class MathBuilderTest {
+
+    @Test
+    void simpleMath() {
+        double result = new MathBuilder.Builder(100).add(200).multiply(10).print().divideIf(20, (a, b) -> a % 2 == 0).sqrt().print().ceil().build().get();
+        assertEquals(13, result);
+    }
+
+    @Test
+    void memoryTest() {
+        long result = new MathBuilder.Builder().set(100).sqrt().remember().add(21).recallIf(a -> a < 50, true).mod(2).build().toLong();
+        assertEquals(0, result);
+    }
+
+    @Test
+    void freeFallDistance() {
+        long distance = new MathBuilder.Builder(9.81).multiply(0.5).multiply(5 * 5).round().build().toLong();
+        assertEquals(123, distance); // Expected result: 0.5 * 9.81 * 25 = 122.625 ≈ 123
+    }
+
+    @Test
+    void batchSalaryProcessing() {
+        double[] salaries = {2000, 3000, 4000, 5000};
+        long[] processedSalaries = new long[salaries.length];
+        for (int i = 0; i < salaries.length; i++) {
+            processedSalaries[i] = new MathBuilder.Builder(salaries[i]).addIf(salaries[i] * 0.1, (sal, bonus) -> sal > 2500).multiply(0.92).round().build().toLong();
+        }
+        long[] expectedSalaries = {1840, 3036, 4048, 5060};
+        assertArrayEquals(expectedSalaries, processedSalaries);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java b/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java
new file mode 100644
index 000000000000..d35d4bb60c73
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java
@@ -0,0 +1,26 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class TestPrintMatrixInSpiralOrder {
+    @Test
+    public void testOne() {
+        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
+        var printClass = new PrintAMatrixInSpiralOrder();
+        List<Integer> res = printClass.print(matrix, matrix.length, matrix[0].length);
+        List<Integer> list = List.of(3, 4, 5, 6, 7, 12, 18, 27, 34, 33, 32, 31, 30, 23, 14, 8, 9, 10, 11, 17, 26, 25, 24, 15, 16);
+        assertIterableEquals(res, list);
+    }
+
+    @Test
+    public void testTwo() {
+        int[][] matrix = {{2, 2}};
+        var printClass = new PrintAMatrixInSpiralOrder();
+        List<Integer> res = printClass.print(matrix, matrix.length, matrix[0].length);
+        List<Integer> list = List.of(2, 2);
+        assertIterableEquals(res, list);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java b/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java
index 014fb4bd24af..a56f79670cf3 100644
--- a/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java
+++ b/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java
@@ -1,27 +1,25 @@
-package com.thealgorithms.searches;
-
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-
-import org.junit.jupiter.api.Test;
-
-public class TestSearchInARowAndColWiseSortedMatrix {
-    @Test
-    public void searchItem() {
-        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
-
-        var test = new SearchInARowAndColWiseSortedMatrix();
-        int[] res = test.search(matrix, 16);
-        int[] expectedResult = {2, 2};
-        assertArrayEquals(expectedResult, res);
-    }
-
-    @Test
-    public void notFound() {
-        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
-
-        var test = new SearchInARowAndColWiseSortedMatrix();
-        int[] res = test.search(matrix, 96);
-        int[] expectedResult = {-1, -1};
-        assertArrayEquals(expectedResult, res);
-    }
-}
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class TestSearchInARowAndColWiseSortedMatrix {
+    @Test
+    public void searchItem() {
+        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
+        var test = new SearchInARowAndColWiseSortedMatrix();
+        int[] res = test.search(matrix, 16);
+        int[] expectedResult = {2, 2};
+        assertArrayEquals(expectedResult, res);
+    }
+
+    @Test
+    public void notFound() {
+        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
+        var test = new SearchInARowAndColWiseSortedMatrix();
+        int[] res = test.search(matrix, 96);
+        int[] expectedResult = {-1, -1};
+        assertArrayEquals(expectedResult, res);
+    }
+}

From 769e4975f63702a5d8f790f88c84edce18985297 Mon Sep 17 00:00:00 2001
From: Hakim's Garage <92100853+sadiul-hakim@users.noreply.github.com>
Date: Sat, 15 Mar 2025 02:34:03 +0600
Subject: [PATCH 0770/1338] Add Parenthesis to MathBuilder (#6193)

---
 .../com/thealgorithms/maths/MathBuilder.java  | 226 +++++++++++++++---
 .../thealgorithms/maths/MathBuilderTest.java  |  14 ++
 2 files changed, 206 insertions(+), 34 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/MathBuilder.java b/src/main/java/com/thealgorithms/maths/MathBuilder.java
index 3534749dd41c..1cf3d8b7fc9a 100644
--- a/src/main/java/com/thealgorithms/maths/MathBuilder.java
+++ b/src/main/java/com/thealgorithms/maths/MathBuilder.java
@@ -26,7 +26,7 @@ public double get() {
     public long toLong() {
         try {
             if (Double.isNaN(result)) {
-                throw new IllegalArgumentException("Cannot convert NaN to long");
+                throw new IllegalArgumentException("Cannot convert NaN to long!");
             }
             if (result == Double.POSITIVE_INFINITY) {
                 return Long.MAX_VALUE;
@@ -48,6 +48,8 @@ public long toLong() {
 
     public static class Builder {
         private double number;
+        private double sideNumber;
+        private boolean inParenthesis;
         private double memory = 0;
 
         public Builder() {
@@ -59,26 +61,44 @@ public Builder(double num) {
         }
 
         public Builder add(double num) {
-            number += num;
+            if (inParenthesis) {
+                sideNumber += num;
+            } else {
+                number += num;
+            }
             return this;
         }
 
         // Takes a number and a condition, only does the operation if condition is true.
         public Builder addIf(double num, BiFunction<Double, Double, Boolean> condition) {
-            if (condition.apply(number, num)) {
+            if (!condition.apply(number, num)) {
+                return this;
+            }
+            if (inParenthesis) {
+                sideNumber += num;
+            } else {
                 number += num;
             }
             return this;
         }
 
         public Builder minus(double num) {
-            number -= num;
+            if (inParenthesis) {
+                sideNumber -= num;
+            } else {
+                number -= num;
+            }
             return this;
         }
 
         // Takes a number and a condition, only does the operation if condition is true.
         public Builder minusIf(double num, BiFunction<Double, Double, Boolean> condition) {
-            if (condition.apply(number, num)) {
+            if (!condition.apply(number, num)) {
+                return this;
+            }
+            if (inParenthesis) {
+                sideNumber -= num;
+            } else {
                 number -= num;
             }
             return this;
@@ -113,7 +133,6 @@ public Builder e() {
         }
 
         public Builder randomInRange(double min, double max) {
-
             if (number != 0) {
                 throw new RuntimeException("Number must be zero for random assignment!");
             }
@@ -123,28 +142,49 @@ public Builder randomInRange(double min, double max) {
         }
 
         public Builder toDegrees() {
-            number = Math.toDegrees(number);
+            if (inParenthesis) {
+                sideNumber = Math.toDegrees(sideNumber);
+            } else {
+                number = Math.toDegrees(number);
+            }
             return this;
         }
 
         public Builder max(double num) {
-            number = Math.max(number, num);
+            if (inParenthesis) {
+                sideNumber = Math.max(sideNumber, num);
+            } else {
+                number = Math.max(number, num);
+            }
             return this;
         }
 
         public Builder min(double num) {
-            number = Math.min(number, num);
+            if (inParenthesis) {
+                sideNumber = Math.min(sideNumber, num);
+            } else {
+                number = Math.min(number, num);
+            }
             return this;
         }
 
         public Builder multiply(double num) {
-            number *= num;
+            if (inParenthesis) {
+                sideNumber *= num;
+            } else {
+                number *= num;
+            }
             return this;
         }
 
         // Takes a number and a condition, only does the operation if condition is true.
         public Builder multiplyIf(double num, BiFunction<Double, Double, Boolean> condition) {
-            if (condition.apply(number, num)) {
+            if (!condition.apply(number, num)) {
+                return this;
+            }
+            if (inParenthesis) {
+                sideNumber *= num;
+            } else {
                 number *= num;
             }
             return this;
@@ -154,7 +194,11 @@ public Builder divide(double num) {
             if (num == 0) {
                 return this;
             }
-            number /= num;
+            if (inParenthesis) {
+                sideNumber /= num;
+            } else {
+                number /= num;
+            }
             return this;
         }
 
@@ -163,107 +207,189 @@ public Builder divideIf(double num, BiFunction<Double, Double, Boolean> conditio
             if (num == 0) {
                 return this;
             }
-            if (condition.apply(number, num)) {
+            if (!condition.apply(number, num)) {
+                return this;
+            }
+            if (inParenthesis) {
+                sideNumber /= num;
+            } else {
                 number /= num;
             }
             return this;
         }
 
         public Builder mod(double num) {
-            number %= num;
+            if (inParenthesis) {
+                sideNumber %= num;
+            } else {
+                number %= num;
+            }
             return this;
         }
 
         // Takes a number and a condition, only does the operation if condition is true.
         public Builder modIf(double num, BiFunction<Double, Double, Boolean> condition) {
-            if (condition.apply(number, num)) {
+            if (!condition.apply(number, num)) {
+                return this;
+            }
+            if (inParenthesis) {
+                sideNumber %= num;
+            } else {
                 number %= num;
             }
             return this;
         }
 
         public Builder pow(double num) {
-            number = Math.pow(number, num);
+            if (inParenthesis) {
+                sideNumber = Math.pow(sideNumber, num);
+            } else {
+                number = Math.pow(number, num);
+            }
             return this;
         }
 
         public Builder sqrt() {
-            number = Math.sqrt(number);
+            if (inParenthesis) {
+                sideNumber = Math.sqrt(sideNumber);
+            } else {
+                number = Math.sqrt(number);
+            }
             return this;
         }
 
         public Builder round() {
-            number = Math.round(number);
+            if (inParenthesis) {
+                sideNumber = Math.round(sideNumber);
+            } else {
+                number = Math.round(number);
+            }
             return this;
         }
 
         public Builder floor() {
-            number = Math.floor(number);
+            if (inParenthesis) {
+                sideNumber = Math.floor(sideNumber);
+            } else {
+                number = Math.floor(number);
+            }
             return this;
         }
 
         public Builder ceil() {
-            number = Math.ceil(number);
+            if (inParenthesis) {
+                sideNumber = Math.ceil(sideNumber);
+            } else {
+                number = Math.ceil(number);
+            }
             return this;
         }
 
         public Builder abs() {
-            number = Math.abs(number);
+            if (inParenthesis) {
+                sideNumber = Math.abs(sideNumber);
+            } else {
+                number = Math.abs(number);
+            }
             return this;
         }
 
         public Builder cbrt() {
-            number = Math.cbrt(number);
+            if (inParenthesis) {
+                sideNumber = Math.cbrt(sideNumber);
+            } else {
+                number = Math.cbrt(number);
+            }
             return this;
         }
 
         public Builder log() {
-            number = Math.log(number);
+            if (inParenthesis) {
+                sideNumber = Math.log(sideNumber);
+            } else {
+                number = Math.log(number);
+            }
             return this;
         }
 
         public Builder log10() {
-            number = Math.log10(number);
+            if (inParenthesis) {
+                sideNumber = Math.log10(sideNumber);
+            } else {
+                number = Math.log10(number);
+            }
             return this;
         }
 
         public Builder sin() {
-            number = Math.sin(number);
+            if (inParenthesis) {
+                sideNumber = Math.sin(sideNumber);
+            } else {
+                number = Math.sin(number);
+            }
             return this;
         }
 
         public Builder cos() {
-            number = Math.cos(number);
+            if (inParenthesis) {
+                sideNumber = Math.cos(sideNumber);
+            } else {
+                number = Math.cos(number);
+            }
             return this;
         }
 
         public Builder tan() {
-            number = Math.tan(number);
+            if (inParenthesis) {
+                sideNumber = Math.tan(sideNumber);
+            } else {
+                number = Math.tan(number);
+            }
             return this;
         }
 
         public Builder sinh() {
-            number = Math.sinh(number);
+            if (inParenthesis) {
+                sideNumber = Math.sinh(sideNumber);
+            } else {
+                number = Math.sinh(number);
+            }
             return this;
         }
 
         public Builder cosh() {
-            number = Math.cosh(number);
+            if (inParenthesis) {
+                sideNumber = Math.cosh(sideNumber);
+            } else {
+                number = Math.cosh(number);
+            }
             return this;
         }
 
         public Builder tanh() {
-            number = Math.tanh(number);
+            if (inParenthesis) {
+                sideNumber = Math.tanh(sideNumber);
+            } else {
+                number = Math.tanh(number);
+            }
             return this;
         }
 
         public Builder exp() {
-            number = Math.exp(number);
+            if (inParenthesis) {
+                sideNumber = Math.exp(sideNumber);
+            } else {
+                number = Math.exp(number);
+            }
             return this;
         }
 
         public Builder toRadians() {
-            number = Math.toRadians(number);
+            if (inParenthesis) {
+                sideNumber = Math.toRadians(sideNumber);
+            } else {
+                number = Math.toRadians(number);
+            }
             return this;
         }
 
@@ -279,7 +405,6 @@ public Builder recall(boolean cleanMemory) {
             if (cleanMemory) {
                 memory = 0;
             }
-
             return this;
         }
 
@@ -292,7 +417,6 @@ public Builder recallIf(Function<Double, Boolean> condition, boolean cleanMemory
             if (cleanMemory) {
                 memory = 0;
             }
-
             return this;
         }
 
@@ -322,6 +446,40 @@ public Builder print() {
             return this;
         }
 
+        public Builder openParenthesis(double num) {
+            sideNumber = num;
+            inParenthesis = true;
+            return this;
+        }
+
+        public Builder closeParenthesisAndPlus() {
+            number += sideNumber;
+            inParenthesis = false;
+            sideNumber = 0;
+            return this;
+        }
+
+        public Builder closeParenthesisAndMinus() {
+            number -= sideNumber;
+            inParenthesis = false;
+            sideNumber = 0;
+            return this;
+        }
+
+        public Builder closeParenthesisAndMultiply() {
+            number *= sideNumber;
+            inParenthesis = false;
+            sideNumber = 0;
+            return this;
+        }
+
+        public Builder closeParenthesisAndDivide() {
+            number /= sideNumber;
+            inParenthesis = false;
+            sideNumber = 0;
+            return this;
+        }
+
         public Builder format(String format) {
             DecimalFormat formater = new DecimalFormat(format);
             String num = formater.format(number);
diff --git a/src/test/java/com/thealgorithms/maths/MathBuilderTest.java b/src/test/java/com/thealgorithms/maths/MathBuilderTest.java
index b6ecc6746701..dc381bfca5d3 100644
--- a/src/test/java/com/thealgorithms/maths/MathBuilderTest.java
+++ b/src/test/java/com/thealgorithms/maths/MathBuilderTest.java
@@ -35,4 +35,18 @@ void batchSalaryProcessing() {
         long[] expectedSalaries = {1840, 3036, 4048, 5060};
         assertArrayEquals(expectedSalaries, processedSalaries);
     }
+
+    @Test
+    void parenthesis() {
+        // 10 + (20*5) - 40 + (100 / 10) = 80
+        double result = new MathBuilder.Builder(10).openParenthesis(20).multiply(5).closeParenthesisAndPlus().minus(40).openParenthesis(100).divide(10).closeParenthesisAndPlus().build().get();
+        assertEquals(80, result);
+    }
+
+    @Test
+    void areaOfCircle() {
+        // Radius is 4
+        double area = new MathBuilder.Builder().pi().openParenthesis(4).multiply(4).closeParenthesisAndMultiply().build().get();
+        assertEquals(Math.PI * 4 * 4, area);
+    }
 }

From 5285a3d7aa6013d250a8ccce7e1ebca54f0351b6 Mon Sep 17 00:00:00 2001
From: David Kong <21kondav@gmail.com>
Date: Fri, 14 Mar 2025 17:57:55 -0400
Subject: [PATCH 0771/1338] Add a linear system solver (#6196)

---
 .../com/thealgorithms/matrix/SolveSystem.java | 71 +++++++++++++++++++
 .../thealgorithms/matrix/SolveSystemTest.java | 21 ++++++
 2 files changed, 92 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/matrix/SolveSystem.java
 create mode 100644 src/test/java/com/thealgorithms/matrix/SolveSystemTest.java

diff --git a/src/main/java/com/thealgorithms/matrix/SolveSystem.java b/src/main/java/com/thealgorithms/matrix/SolveSystem.java
new file mode 100644
index 000000000000..9e683bc4dc5c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/matrix/SolveSystem.java
@@ -0,0 +1,71 @@
+package com.thealgorithms.matrix;
+
+/**
+ * This class implements an algorithm for solving a system of equations of the form Ax=b using gaussian elimination and back substitution.
+ *
+ * @link <a href="https://en.wikipedia.org/wiki/Gaussian_elimination">Gaussian Elimination Wiki</a>
+ * @see InverseOfMatrix finds the full of inverse of a matrice, but is not required to solve a system.
+ */
+public final class SolveSystem {
+    private SolveSystem() {
+    }
+
+    /**
+     * Problem: Given a matrix A and vector b, solve the linear system Ax = b for the vector x.\
+     * <p>
+     * <b>This OVERWRITES the input matrix to save on memory</b>
+     *
+     * @param matrix    - a square matrix of doubles
+     * @param constants - an array of constant
+     * @return solutions
+     */
+    public static double[] solveSystem(double[][] matrix, double[] constants) {
+        final double tol = 0.00000001; // tolerance for round off
+        for (int k = 0; k < matrix.length - 1; k++) {
+            // find the largest value in column (to avoid zero pivots)
+            double maxVal = Math.abs(matrix[k][k]);
+            int maxIdx = k;
+            for (int j = k + 1; j < matrix.length; j++) {
+                if (Math.abs(matrix[j][k]) > maxVal) {
+                    maxVal = matrix[j][k];
+                    maxIdx = j;
+                }
+            }
+            if (Math.abs(maxVal) < tol) {
+                // hope the matrix works out
+                continue;
+            }
+            // swap rows
+            double[] temp = matrix[k];
+            matrix[k] = matrix[maxIdx];
+            matrix[maxIdx] = temp;
+            double tempConst = constants[k];
+            constants[k] = constants[maxIdx];
+            constants[maxIdx] = tempConst;
+            for (int i = k + 1; i < matrix.length; i++) {
+                // compute multipliers and save them in the column
+                matrix[i][k] /= matrix[k][k];
+                for (int j = k + 1; j < matrix.length; j++) {
+                    matrix[i][j] -= matrix[i][k] * matrix[k][j];
+                }
+                constants[i] -= matrix[i][k] * constants[k];
+            }
+        }
+        // back substitution
+        double[] x = new double[constants.length];
+        System.arraycopy(constants, 0, x, 0, constants.length);
+        for (int i = matrix.length - 1; i >= 0; i--) {
+            double sum = 0;
+            for (int j = i + 1; j < matrix.length; j++) {
+                sum += matrix[i][j] * x[j];
+            }
+            x[i] = constants[i] - sum;
+            if (Math.abs(matrix[i][i]) > tol) {
+                x[i] /= matrix[i][i];
+            } else {
+                throw new IllegalArgumentException("Matrix was found to be singular");
+            }
+        }
+        return x;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/matrix/SolveSystemTest.java b/src/test/java/com/thealgorithms/matrix/SolveSystemTest.java
new file mode 100644
index 000000000000..c8d289bd8339
--- /dev/null
+++ b/src/test/java/com/thealgorithms/matrix/SolveSystemTest.java
@@ -0,0 +1,21 @@
+package com.thealgorithms.matrix;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class SolveSystemTest {
+
+    @ParameterizedTest
+    @MethodSource({"matrixGenerator"})
+    void solveSystem(double[][] matrix, double[] constants, double[] solution) {
+        double[] expected = SolveSystem.solveSystem(matrix, constants);
+        assertArrayEquals(expected, solution, 1.0E-10, "Solution does not match expected");
+    }
+    private static Stream<Arguments> matrixGenerator() {
+        return Stream.of(Arguments.of(new double[][] {{-5, 8, -4}, {0, 6, 3}, {0, 0, -4}}, new double[] {38, -9, 20}, new double[] {-2, 1, -5}), Arguments.of(new double[][] {{-2, -1, -1}, {3, 4, 1}, {3, 6, 5}}, new double[] {-11, 19, 43}, new double[] {2, 2, 5}));
+    }
+}

From 8509be15f0888e09af5a651e668827b21585aec0 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 15 Mar 2025 00:52:55 +0100
Subject: [PATCH 0772/1338] Bump org.junit:junit-bom from 5.12.0 to 5.12.1
 (#6197)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.12.0 to 5.12.1.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.12.0...r5.12.1)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 04073aef3d90..fe738d9776a4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.12.0</version>
+                <version>5.12.1</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 1a69a2da156d4f1576e16f1ae6e85a59594085ba Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 17 Mar 2025 23:23:19 +0100
Subject: [PATCH 0773/1338] Bump com.github.spotbugs:spotbugs-maven-plugin from
 4.9.2.0 to 4.9.3.0 (#6198)

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.2.0 to 4.9.3.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.2.0...spotbugs-maven-plugin-4.9.3.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index fe738d9776a4..b757c18078bd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -123,7 +123,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.2.0</version>
+                <version>4.9.3.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From b44ecf7ef6635e6c293ec7e8f9ad523ce4402224 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 17 Mar 2025 23:28:41 +0100
Subject: [PATCH 0774/1338] Bump org.mockito:mockito-core from 5.16.0 to 5.16.1
 (#6199)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.16.0 to 5.16.1.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.16.0...v5.16.1)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b757c18078bd..b8ab98289244 100644
--- a/pom.xml
+++ b/pom.xml
@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.16.0</version>
+            <version>5.16.1</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 45148874e841c3b0db0a5a0d46e2871f30b0d3e0 Mon Sep 17 00:00:00 2001
From: Sufiyan Chougule <100443252+Sufi-san@users.noreply.github.com>
Date: Tue, 18 Mar 2025 15:59:20 +0530
Subject: [PATCH 0775/1338] Add feature to convert numeric words to their
 number representation (#6195)

---
 DIRECTORY.md                                  |   2 +
 .../conversions/WordsToNumber.java            | 343 ++++++++++++++++++
 .../conversions/WordsToNumberTest.java        | 114 ++++++
 3 files changed, 459 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/WordsToNumber.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/WordsToNumberTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index f53a6220c517..fe9e440da3e2 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -118,6 +118,7 @@
             * [TurkishToLatinConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java)
             * [UnitConversions](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/UnitConversions.java)
             * [UnitsConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/UnitsConverter.java)
+            * [WordsToNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/WordsToNumber.java)
           * datastructures
             * bags
               * [Bag](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/bags/Bag.java)
@@ -840,6 +841,7 @@
             * [TurkishToLatinConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java)
             * [UnitConversionsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java)
             * [UnitsConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java)
+            * [WordsToNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/WordsToNumberTest.java)
           * datastructures
             * bag
               * [BagTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java)
diff --git a/src/main/java/com/thealgorithms/conversions/WordsToNumber.java b/src/main/java/com/thealgorithms/conversions/WordsToNumber.java
new file mode 100644
index 000000000000..e2b81a0f4b47
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/WordsToNumber.java
@@ -0,0 +1,343 @@
+package com.thealgorithms.conversions;
+
+import java.io.Serial;
+import java.math.BigDecimal;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ A Java-based utility for converting English word representations of numbers
+ into their numeric form. This utility supports whole numbers, decimals,
+ large values up to trillions, and even scientific notation where applicable.
+ It ensures accurate parsing while handling edge cases like negative numbers,
+ improper word placements, and ambiguous inputs.
+ *
+ */
+
+public final class WordsToNumber {
+
+    private WordsToNumber() {
+    }
+
+    private enum NumberWord {
+        ZERO("zero", 0),
+        ONE("one", 1),
+        TWO("two", 2),
+        THREE("three", 3),
+        FOUR("four", 4),
+        FIVE("five", 5),
+        SIX("six", 6),
+        SEVEN("seven", 7),
+        EIGHT("eight", 8),
+        NINE("nine", 9),
+        TEN("ten", 10),
+        ELEVEN("eleven", 11),
+        TWELVE("twelve", 12),
+        THIRTEEN("thirteen", 13),
+        FOURTEEN("fourteen", 14),
+        FIFTEEN("fifteen", 15),
+        SIXTEEN("sixteen", 16),
+        SEVENTEEN("seventeen", 17),
+        EIGHTEEN("eighteen", 18),
+        NINETEEN("nineteen", 19),
+        TWENTY("twenty", 20),
+        THIRTY("thirty", 30),
+        FORTY("forty", 40),
+        FIFTY("fifty", 50),
+        SIXTY("sixty", 60),
+        SEVENTY("seventy", 70),
+        EIGHTY("eighty", 80),
+        NINETY("ninety", 90);
+
+        private final String word;
+        private final int value;
+
+        NumberWord(String word, int value) {
+            this.word = word;
+            this.value = value;
+        }
+
+        public static Integer getValue(String word) {
+            for (NumberWord num : values()) {
+                if (word.equals(num.word)) {
+                    return num.value;
+                }
+            }
+            return null;
+        }
+    }
+
+    private enum PowerOfTen {
+        THOUSAND("thousand", new BigDecimal("1000")),
+        MILLION("million", new BigDecimal("1000000")),
+        BILLION("billion", new BigDecimal("1000000000")),
+        TRILLION("trillion", new BigDecimal("1000000000000"));
+
+        private final String word;
+        private final BigDecimal value;
+
+        PowerOfTen(String word, BigDecimal value) {
+            this.word = word;
+            this.value = value;
+        }
+
+        public static BigDecimal getValue(String word) {
+            for (PowerOfTen power : values()) {
+                if (word.equals(power.word)) {
+                    return power.value;
+                }
+            }
+            return null;
+        }
+    }
+
+    public static String convert(String numberInWords) {
+        if (numberInWords == null) {
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.NULL_INPUT, "");
+        }
+
+        ArrayDeque<String> wordDeque = preprocessWords(numberInWords);
+        BigDecimal completeNumber = convertWordQueueToBigDecimal(wordDeque);
+
+        return completeNumber.toString();
+    }
+
+    public static BigDecimal convertToBigDecimal(String numberInWords) {
+        String conversionResult = convert(numberInWords);
+        return new BigDecimal(conversionResult);
+    }
+
+    private static ArrayDeque<String> preprocessWords(String numberInWords) {
+        String[] wordSplitArray = numberInWords.trim().split("[ ,-]");
+        ArrayDeque<String> wordDeque = new ArrayDeque<>();
+        for (String word : wordSplitArray) {
+            if (word.isEmpty()) {
+                continue;
+            }
+            wordDeque.add(word.toLowerCase());
+        }
+        if (wordDeque.isEmpty()) {
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.NULL_INPUT, "");
+        }
+        return wordDeque;
+    }
+
+    private static void handleConjunction(boolean prevNumWasHundred, boolean prevNumWasPowerOfTen, ArrayDeque<String> wordDeque) {
+        if (wordDeque.isEmpty()) {
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.INVALID_CONJUNCTION, "");
+        }
+
+        String nextWord = wordDeque.pollFirst();
+        String afterNextWord = wordDeque.peekFirst();
+
+        wordDeque.addFirst(nextWord);
+
+        Integer number = NumberWord.getValue(nextWord);
+
+        boolean isPrevWordValid = prevNumWasHundred || prevNumWasPowerOfTen;
+        boolean isNextWordValid = number != null && (number >= 10 || afterNextWord == null || "point".equals(afterNextWord));
+
+        if (!isPrevWordValid || !isNextWordValid) {
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.INVALID_CONJUNCTION, "");
+        }
+    }
+
+    private static BigDecimal handleHundred(BigDecimal currentChunk, String word, boolean prevNumWasPowerOfTen) {
+        boolean currentChunkIsZero = currentChunk.compareTo(BigDecimal.ZERO) == 0;
+        if (currentChunk.compareTo(BigDecimal.TEN) >= 0 || prevNumWasPowerOfTen) {
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.UNEXPECTED_WORD, word);
+        }
+        if (currentChunkIsZero) {
+            currentChunk = currentChunk.add(BigDecimal.ONE);
+        }
+        return currentChunk.multiply(BigDecimal.valueOf(100));
+    }
+
+    private static void handlePowerOfTen(List<BigDecimal> chunks, BigDecimal currentChunk, BigDecimal powerOfTen, String word, boolean prevNumWasPowerOfTen) {
+        boolean currentChunkIsZero = currentChunk.compareTo(BigDecimal.ZERO) == 0;
+        if (currentChunkIsZero || prevNumWasPowerOfTen) {
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.UNEXPECTED_WORD, word);
+        }
+        BigDecimal nextChunk = currentChunk.multiply(powerOfTen);
+
+        if (!(chunks.isEmpty() || isAdditionSafe(chunks.getLast(), nextChunk))) {
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.UNEXPECTED_WORD, word);
+        }
+        chunks.add(nextChunk);
+    }
+
+    private static BigDecimal handleNumber(Collection<BigDecimal> chunks, BigDecimal currentChunk, String word, Integer number) {
+        boolean currentChunkIsZero = currentChunk.compareTo(BigDecimal.ZERO) == 0;
+        if (number == 0 && !(currentChunkIsZero && chunks.isEmpty())) {
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.UNEXPECTED_WORD, word);
+        }
+        BigDecimal bigDecimalNumber = BigDecimal.valueOf(number);
+
+        if (!currentChunkIsZero && !isAdditionSafe(currentChunk, bigDecimalNumber)) {
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.UNEXPECTED_WORD, word);
+        }
+        return currentChunk.add(bigDecimalNumber);
+    }
+
+    private static void handlePoint(Collection<BigDecimal> chunks, BigDecimal currentChunk, ArrayDeque<String> wordDeque) {
+        boolean currentChunkIsZero = currentChunk.compareTo(BigDecimal.ZERO) == 0;
+        if (!currentChunkIsZero) {
+            chunks.add(currentChunk);
+        }
+
+        String decimalPart = convertDecimalPart(wordDeque);
+        chunks.add(new BigDecimal(decimalPart));
+    }
+
+    private static void handleNegative(boolean isNegative) {
+        if (isNegative) {
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.MULTIPLE_NEGATIVES, "");
+        }
+        throw new WordsToNumberException(WordsToNumberException.ErrorType.INVALID_NEGATIVE, "");
+    }
+
+    private static BigDecimal convertWordQueueToBigDecimal(ArrayDeque<String> wordDeque) {
+        BigDecimal currentChunk = BigDecimal.ZERO;
+        List<BigDecimal> chunks = new ArrayList<>();
+
+        boolean isNegative = "negative".equals(wordDeque.peek());
+        if (isNegative) {
+            wordDeque.poll();
+        }
+
+        boolean prevNumWasHundred = false;
+        boolean prevNumWasPowerOfTen = false;
+
+        while (!wordDeque.isEmpty()) {
+            String word = wordDeque.poll();
+
+            switch (word) {
+                case "and" -> {
+                    handleConjunction(prevNumWasHundred, prevNumWasPowerOfTen, wordDeque);
+                    continue;
+                }
+                case "hundred" -> {
+                    currentChunk = handleHundred(currentChunk, word, prevNumWasPowerOfTen);
+                    prevNumWasHundred = true;
+                    continue;
+                }
+                default -> {
+
+                }
+            }
+            prevNumWasHundred = false;
+
+            BigDecimal powerOfTen = PowerOfTen.getValue(word);
+            if (powerOfTen != null) {
+                handlePowerOfTen(chunks, currentChunk, powerOfTen, word, prevNumWasPowerOfTen);
+                currentChunk = BigDecimal.ZERO;
+                prevNumWasPowerOfTen = true;
+                continue;
+            }
+            prevNumWasPowerOfTen = false;
+
+            Integer number = NumberWord.getValue(word);
+            if (number != null) {
+                currentChunk = handleNumber(chunks, currentChunk, word, number);
+                continue;
+            }
+
+            switch (word) {
+                case "point" -> {
+                    handlePoint(chunks, currentChunk, wordDeque);
+                    currentChunk = BigDecimal.ZERO;
+                    continue;
+                }
+                case "negative" -> {
+                    handleNegative(isNegative);
+                }
+                default -> {
+
+                }
+            }
+
+            throw new WordsToNumberException(WordsToNumberException.ErrorType.UNKNOWN_WORD, word);
+        }
+
+        if (currentChunk.compareTo(BigDecimal.ZERO) != 0) {
+            chunks.add(currentChunk);
+        }
+
+        BigDecimal completeNumber = combineChunks(chunks);
+        return isNegative ? completeNumber.multiply(BigDecimal.valueOf(-1))
+                :
+                    completeNumber;
+                }
+
+                private static boolean isAdditionSafe(BigDecimal currentChunk, BigDecimal number) {
+                    int chunkDigitCount = currentChunk.toString().length();
+                    int numberDigitCount = number.toString().length();
+                    return chunkDigitCount > numberDigitCount;
+                }
+
+                private static String convertDecimalPart(ArrayDeque<String> wordDeque) {
+                    StringBuilder decimalPart = new StringBuilder(".");
+
+                    while (!wordDeque.isEmpty()) {
+                        String word = wordDeque.poll();
+                        Integer number = NumberWord.getValue(word);
+                        if (number == null) {
+                            throw new WordsToNumberException(WordsToNumberException.ErrorType.UNEXPECTED_WORD_AFTER_POINT, word);
+                        }
+                        decimalPart.append(number);
+                    }
+
+                    boolean missingNumbers = decimalPart.length() == 1;
+                    if (missingNumbers) {
+                        throw new WordsToNumberException(WordsToNumberException.ErrorType.MISSING_DECIMAL_NUMBERS, "");
+                    }
+                    return decimalPart.toString();
+                }
+
+                private static BigDecimal combineChunks(List<BigDecimal> chunks) {
+                    BigDecimal completeNumber = BigDecimal.ZERO;
+                    for (BigDecimal chunk : chunks) {
+                        completeNumber = completeNumber.add(chunk);
+                    }
+                    return completeNumber;
+                }
+        }
+
+        class WordsToNumberException extends RuntimeException {
+
+                @Serial private static final long serialVersionUID = 1L;
+
+                enum ErrorType {
+                    NULL_INPUT("'null' or empty input provided"),
+                    UNKNOWN_WORD("Unknown Word: "),
+                    UNEXPECTED_WORD("Unexpected Word: "),
+                    UNEXPECTED_WORD_AFTER_POINT("Unexpected Word (after Point): "),
+                    MISSING_DECIMAL_NUMBERS("Decimal part is missing numbers."),
+                    MULTIPLE_NEGATIVES("Multiple 'Negative's detected."),
+                    INVALID_NEGATIVE("Incorrect 'negative' placement"),
+                    INVALID_CONJUNCTION("Incorrect 'and' placement");
+
+                    private final String message;
+
+                    ErrorType(String message) {
+                        this.message = message;
+                    }
+
+                    public String formatMessage(String details) {
+                        return "Invalid Input. " + message + (details.isEmpty() ? "" : details);
+                    }
+                }
+
+                public final ErrorType errorType;
+
+                WordsToNumberException(ErrorType errorType, String details) {
+                    super(errorType.formatMessage(details));
+                    this.errorType = errorType;
+                }
+
+                public ErrorType getErrorType() {
+                    return errorType;
+                }
+        }
diff --git a/src/test/java/com/thealgorithms/conversions/WordsToNumberTest.java b/src/test/java/com/thealgorithms/conversions/WordsToNumberTest.java
new file mode 100644
index 000000000000..fbf63e37946b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/WordsToNumberTest.java
@@ -0,0 +1,114 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.math.BigDecimal;
+import org.junit.jupiter.api.Test;
+
+public class WordsToNumberTest {
+
+    @Test
+    void testNullInput() {
+        WordsToNumberException exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert(null));
+        assertEquals(WordsToNumberException.ErrorType.NULL_INPUT, exception.getErrorType(), "Exception should be of type NULL_INPUT");
+    }
+
+    @Test
+    void testStandardCases() {
+        assertEquals("0", WordsToNumber.convert("zero"), "'zero' should convert to '0'");
+        assertEquals("5", WordsToNumber.convert("five"), "'five' should convert to '5'");
+        assertEquals("21", WordsToNumber.convert("twenty one"), "'twenty one' should convert to '21'");
+        assertEquals("101", WordsToNumber.convert("one hundred one"), "'one hundred' should convert to '101'");
+        assertEquals("342", WordsToNumber.convert("three hundred and forty two"), "'three hundred and forty two' should convert to '342'");
+    }
+
+    @Test
+    void testLargeNumbers() {
+        assertEquals("1000000", WordsToNumber.convert("one million"), "'one million' should convert to '1000000'");
+        assertEquals("1000000000", WordsToNumber.convert("one billion"), "'one billion' should convert to '1000000000'");
+        assertEquals("1000000000000", WordsToNumber.convert("one trillion"), "'one trillion' should convert to '1000000000000'");
+        assertEquals("999000000900999", WordsToNumber.convert("nine hundred ninety nine trillion nine hundred thousand nine hundred and ninety nine"), "'nine hundred ninety nine trillion nine hundred thousand nine hundred and ninety nine' should convert to '999000000900999'");
+    }
+
+    @Test
+    void testNegativeNumbers() {
+        assertEquals("-5", WordsToNumber.convert("negative five"), "'negative five' should convert to '-5'");
+        assertEquals("-120", WordsToNumber.convert("negative one hundred and twenty"), "'negative one hundred and twenty' should convert correctly");
+    }
+
+    @Test
+    void testNegativeLargeNumbers() {
+        assertEquals("-1000000000000", WordsToNumber.convert("negative one trillion"), "'negative one trillion' should convert to '-1000000000000'");
+        assertEquals("-9876543210987", WordsToNumber.convert("Negative Nine Trillion Eight Hundred Seventy Six Billion Five Hundred Forty Three Million Two Hundred Ten Thousand Nine Hundred Eighty Seven"), "");
+    }
+
+    @Test
+    void testDecimalNumbers() {
+        assertEquals("3.1415", WordsToNumber.convert("three point one four one five"), "'three point one four one five' should convert to '3.1415'");
+        assertEquals("-2.718", WordsToNumber.convert("negative two point seven one eight"), "'negative two point seven one eight' should convert to '-2.718'");
+        assertEquals("-1E-7", WordsToNumber.convert("negative zero point zero zero zero zero zero zero one"), "'negative zero point zero zero zero zero zero zero one' should convert to '-1E-7'");
+    }
+
+    @Test
+    void testLargeDecimalNumbers() {
+        assertEquals("1000000000.0000000001", WordsToNumber.convert("one billion point zero zero zero zero zero zero zero zero zero one"), "Tests a large whole number with a tiny fractional part");
+        assertEquals("999999999999999.9999999999999",
+            WordsToNumber.convert("nine hundred ninety nine trillion nine hundred ninety nine billion nine hundred ninety nine million nine hundred ninety nine thousand nine hundred ninety nine point nine nine nine nine nine nine nine nine nine nine nine nine nine"),
+            "Tests maximum scale handling for large decimal numbers");
+        assertEquals("0.505", WordsToNumber.convert("zero point five zero five"), "Tests a decimal with an internal zero, ensuring correct parsing");
+        assertEquals("42.00000000000001", WordsToNumber.convert("forty two point zero zero zero zero zero zero zero zero zero zero zero zero zero one"), "Tests a decimal with leading zeros before a significant figure");
+        assertEquals("7.89E-7", WordsToNumber.convert("zero point zero zero zero zero zero zero seven eight nine"), "Tests scientific notation for a small decimal with multiple digits");
+        assertEquals("0.999999", WordsToNumber.convert("zero point nine nine nine nine nine nine"), "Tests a decimal close to one with multiple repeated digits");
+    }
+
+    @Test
+    void testCaseInsensitivity() {
+        assertEquals("21", WordsToNumber.convert("TWENTY-ONE"), "Uppercase should still convert correctly");
+        assertEquals("-100.0001", WordsToNumber.convert("negAtiVe OnE HuNdReD, point ZeRO Zero zERo ONE"), "Mixed case should still convert correctly");
+        assertEquals("-225647.00019", WordsToNumber.convert("nEgative twO HundRed, and twenty-Five thOusaNd, six huNdred Forty-Seven, Point zero zero zero One nInE"));
+    }
+
+    @Test
+    void testInvalidInputs() {
+        WordsToNumberException exception;
+
+        exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert("negative one hundred AlPha"));
+        assertEquals(WordsToNumberException.ErrorType.UNKNOWN_WORD, exception.getErrorType());
+
+        exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert("twenty thirteen"));
+        assertEquals(WordsToNumberException.ErrorType.UNEXPECTED_WORD, exception.getErrorType());
+
+        exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert("negative negative ten"));
+        assertEquals(WordsToNumberException.ErrorType.MULTIPLE_NEGATIVES, exception.getErrorType());
+
+        exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert("one hundred hundred"));
+        assertEquals(WordsToNumberException.ErrorType.UNEXPECTED_WORD, exception.getErrorType());
+
+        exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert("one thousand and hundred"));
+        assertEquals(WordsToNumberException.ErrorType.INVALID_CONJUNCTION, exception.getErrorType());
+
+        exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert("one thousand hundred"));
+        assertEquals(WordsToNumberException.ErrorType.UNEXPECTED_WORD, exception.getErrorType());
+
+        exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert("nine hundred and nine hundred"));
+        assertEquals(WordsToNumberException.ErrorType.INVALID_CONJUNCTION, exception.getErrorType());
+
+        exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert("forty two point"));
+        assertEquals(WordsToNumberException.ErrorType.MISSING_DECIMAL_NUMBERS, exception.getErrorType());
+
+        exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert("sixty seven point hello"));
+        assertEquals(WordsToNumberException.ErrorType.UNEXPECTED_WORD_AFTER_POINT, exception.getErrorType());
+
+        exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convert("one negative"));
+        assertEquals(WordsToNumberException.ErrorType.INVALID_NEGATIVE, exception.getErrorType());
+    }
+
+    @Test
+    void testConvertToBigDecimal() {
+        assertEquals(new BigDecimal("-100000000000000.056"), WordsToNumber.convertToBigDecimal("negative one hundred trillion point zero five six"), "should convert to appropriate BigDecimal value");
+
+        WordsToNumberException exception = assertThrows(WordsToNumberException.class, () -> WordsToNumber.convertToBigDecimal(null));
+        assertEquals(WordsToNumberException.ErrorType.NULL_INPUT, exception.getErrorType(), "Exception should be of type NULL_INPUT");
+    }
+}

From 0072ed9aa72eefc57361f96f27db17a86b790936 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Mon, 31 Mar 2025 19:20:58 +0200
Subject: [PATCH 0776/1338] style: do not suppress `lossy-conversions` (#6206)

---
 pom.xml                                           |  1 -
 .../java/com/thealgorithms/ciphers/Caesar.java    | 15 +++++++++------
 .../java/com/thealgorithms/maths/AliquotSum.java  |  2 +-
 .../com/thealgorithms/maths/PerfectNumber.java    |  2 +-
 4 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/pom.xml b/pom.xml
index b8ab98289244..43c0a2b28627 100644
--- a/pom.xml
+++ b/pom.xml
@@ -78,7 +78,6 @@
                         <arg>-Xlint:-auxiliaryclass</arg>
                         <arg>-Xlint:-rawtypes</arg>
                         <arg>-Xlint:-unchecked</arg>
-                        <arg>-Xlint:-lossy-conversions</arg>
                         <arg>-Werror</arg>
                     </compilerArgs>
                 </configuration>
diff --git a/src/main/java/com/thealgorithms/ciphers/Caesar.java b/src/main/java/com/thealgorithms/ciphers/Caesar.java
index 61c444cf6463..23535bc2b5d2 100644
--- a/src/main/java/com/thealgorithms/ciphers/Caesar.java
+++ b/src/main/java/com/thealgorithms/ciphers/Caesar.java
@@ -9,6 +9,9 @@
  * @author khalil2535
  */
 public class Caesar {
+    private static char normalizeShift(final int shift) {
+        return (char) (shift % 26);
+    }
 
     /**
      * Encrypt text by shifting every Latin char by add number shift for ASCII
@@ -19,7 +22,7 @@ public class Caesar {
     public String encode(String message, int shift) {
         StringBuilder encoded = new StringBuilder();
 
-        shift %= 26;
+        final char shiftChar = normalizeShift(shift);
 
         final int length = message.length();
         for (int i = 0; i < length; i++) {
@@ -29,10 +32,10 @@ public String encode(String message, int shift) {
             char current = message.charAt(i); // Java law : char + int = char
 
             if (isCapitalLatinLetter(current)) {
-                current += shift;
+                current += shiftChar;
                 encoded.append((char) (current > 'Z' ? current - 26 : current)); // 26 = number of latin letters
             } else if (isSmallLatinLetter(current)) {
-                current += shift;
+                current += shiftChar;
                 encoded.append((char) (current > 'z' ? current - 26 : current)); // 26 = number of latin letters
             } else {
                 encoded.append(current);
@@ -50,16 +53,16 @@ public String encode(String message, int shift) {
     public String decode(String encryptedMessage, int shift) {
         StringBuilder decoded = new StringBuilder();
 
-        shift %= 26;
+        final char shiftChar = normalizeShift(shift);
 
         final int length = encryptedMessage.length();
         for (int i = 0; i < length; i++) {
             char current = encryptedMessage.charAt(i);
             if (isCapitalLatinLetter(current)) {
-                current -= shift;
+                current -= shiftChar;
                 decoded.append((char) (current < 'A' ? current + 26 : current)); // 26 = number of latin letters
             } else if (isSmallLatinLetter(current)) {
-                current -= shift;
+                current -= shiftChar;
                 decoded.append((char) (current < 'a' ? current + 26 : current)); // 26 = number of latin letters
             } else {
                 decoded.append(current);
diff --git a/src/main/java/com/thealgorithms/maths/AliquotSum.java b/src/main/java/com/thealgorithms/maths/AliquotSum.java
index 0dbc58bed605..996843b56826 100644
--- a/src/main/java/com/thealgorithms/maths/AliquotSum.java
+++ b/src/main/java/com/thealgorithms/maths/AliquotSum.java
@@ -56,7 +56,7 @@ public static int getAliquotSum(int n) {
         // if n is a perfect square then its root was added twice in above loop, so subtracting root
         // from sum
         if (root == (int) root) {
-            sum -= root;
+            sum -= (int) root;
         }
         return sum;
     }
diff --git a/src/main/java/com/thealgorithms/maths/PerfectNumber.java b/src/main/java/com/thealgorithms/maths/PerfectNumber.java
index 2a935b067094..f299d08e5d27 100644
--- a/src/main/java/com/thealgorithms/maths/PerfectNumber.java
+++ b/src/main/java/com/thealgorithms/maths/PerfectNumber.java
@@ -63,7 +63,7 @@ public static boolean isPerfectNumber2(int n) {
         // if n is a perfect square then its root was added twice in above loop, so subtracting root
         // from sum
         if (root == (int) root) {
-            sum -= root;
+            sum -= (int) root;
         }
 
         return sum == n;

From 743f9660a88df89c091ccaad5a1a05a8e4597575 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Tue, 1 Apr 2025 00:18:19 +0200
Subject: [PATCH 0777/1338] Add Traveling Salesman Problem (#6205)

---
 .../graph/TravelingSalesman.java              | 155 ++++++++++++++++++
 .../graph/TravelingSalesmanTest.java          | 127 ++++++++++++++
 2 files changed, 282 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/TravelingSalesman.java
 create mode 100644 src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java

diff --git a/src/main/java/com/thealgorithms/graph/TravelingSalesman.java b/src/main/java/com/thealgorithms/graph/TravelingSalesman.java
new file mode 100644
index 000000000000..14bf89f57cf3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/TravelingSalesman.java
@@ -0,0 +1,155 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * This class provides solutions to the Traveling Salesman Problem (TSP) using both brute-force and dynamic programming approaches.
+ * For more information, see <a href="https://en.wikipedia.org/wiki/Travelling_salesman_problem">Wikipedia</a>.
+ * @author  <a href="https://github.com/DenizAltunkapan">Deniz Altunkapan</a>
+ */
+
+public final class TravelingSalesman {
+
+    // Private constructor to prevent instantiation
+    private TravelingSalesman() {
+    }
+
+    /**
+     * Solves the Traveling Salesman Problem (TSP) using brute-force approach.
+     * This method generates all possible permutations of cities, calculates the total distance for each route, and returns the shortest distance found.
+     *
+     * @param distanceMatrix A square matrix where element [i][j] represents the distance from city i to city j.
+     * @return The shortest possible route distance visiting all cities exactly once and returning to the starting city.
+     */
+    public static int bruteForce(int[][] distanceMatrix) {
+        if (distanceMatrix.length <= 1) {
+            return 0;
+        }
+
+        List<Integer> cities = new ArrayList<>();
+        for (int i = 1; i < distanceMatrix.length; i++) {
+            cities.add(i);
+        }
+
+        List<List<Integer>> permutations = generatePermutations(cities);
+        int minDistance = Integer.MAX_VALUE;
+
+        for (List<Integer> permutation : permutations) {
+            List<Integer> route = new ArrayList<>();
+            route.add(0);
+            route.addAll(permutation);
+            int currentDistance = calculateDistance(distanceMatrix, route);
+            if (currentDistance < minDistance) {
+                minDistance = currentDistance;
+            }
+        }
+
+        return minDistance;
+    }
+
+    /**
+     * Computes the total distance of a given route.
+     *
+     * @param distanceMatrix A square matrix where element [i][j] represents the
+     *                       distance from city i to city j.
+     * @param route          A list representing the order in which the cities are visited.
+     * @return The total distance of the route, or Integer.MAX_VALUE if the route is invalid.
+     */
+    public static int calculateDistance(int[][] distanceMatrix, List<Integer> route) {
+        int distance = 0;
+        for (int i = 0; i < route.size() - 1; i++) {
+            int d = distanceMatrix[route.get(i)][route.get(i + 1)];
+            if (d == Integer.MAX_VALUE) {
+                return Integer.MAX_VALUE;
+            }
+            distance += d;
+        }
+        int returnDist = distanceMatrix[route.get(route.size() - 1)][route.get(0)];
+        return (returnDist == Integer.MAX_VALUE) ? Integer.MAX_VALUE : distance + returnDist;
+    }
+
+    /**
+     * Generates all permutations of a given list of cities.
+     *
+     * @param cities A list of cities to permute.
+     * @return A list of all possible permutations.
+     */
+    private static List<List<Integer>> generatePermutations(List<Integer> cities) {
+        List<List<Integer>> permutations = new ArrayList<>();
+        permute(cities, 0, permutations);
+        return permutations;
+    }
+
+    /**
+     * Recursively generates permutations using backtracking.
+     *
+     * @param arr     The list of cities.
+     * @param k       The current index in the permutation process.
+     * @param output  The list to store generated permutations.
+     */
+    private static void permute(List<Integer> arr, int k, List<List<Integer>> output) {
+        if (k == arr.size()) {
+            output.add(new ArrayList<>(arr));
+            return;
+        }
+        for (int i = k; i < arr.size(); i++) {
+            Collections.swap(arr, i, k);
+            permute(arr, k + 1, output);
+            Collections.swap(arr, i, k);
+        }
+    }
+
+    /**
+     * Solves the Traveling Salesman Problem (TSP) using dynamic programming with the Held-Karp algorithm.
+     *
+     * @param distanceMatrix A square matrix where element [i][j] represents the distance from city i to city j.
+     * @return The shortest possible route distance visiting all cities exactly once and returning to the starting city.
+     * @throws IllegalArgumentException if the input matrix is not square.
+     */
+    public static int dynamicProgramming(int[][] distanceMatrix) {
+        if (distanceMatrix.length == 0) {
+            return 0;
+        }
+        int n = distanceMatrix.length;
+
+        for (int[] row : distanceMatrix) {
+            if (row.length != n) {
+                throw new IllegalArgumentException("Matrix must be square");
+            }
+        }
+
+        int[][] dp = new int[n][1 << n];
+        for (int[] row : dp) {
+            Arrays.fill(row, Integer.MAX_VALUE);
+        }
+        dp[0][1] = 0;
+
+        for (int mask = 1; mask < (1 << n); mask++) {
+            for (int u = 0; u < n; u++) {
+                if ((mask & (1 << u)) == 0 || dp[u][mask] == Integer.MAX_VALUE) {
+                    continue;
+                }
+                for (int v = 0; v < n; v++) {
+                    if ((mask & (1 << v)) != 0 || distanceMatrix[u][v] == Integer.MAX_VALUE) {
+                        continue;
+                    }
+                    int newMask = mask | (1 << v);
+                    dp[v][newMask] = Math.min(dp[v][newMask], dp[u][mask] + distanceMatrix[u][v]);
+                }
+            }
+        }
+
+        int minDistance = Integer.MAX_VALUE;
+        int fullMask = (1 << n) - 1;
+        for (int i = 1; i < n; i++) {
+            if (dp[i][fullMask] != Integer.MAX_VALUE && distanceMatrix[i][0] != Integer.MAX_VALUE) {
+                minDistance = Math.min(minDistance, dp[i][fullMask] + distanceMatrix[i][0]);
+            }
+        }
+
+        return minDistance == Integer.MAX_VALUE ? 0 : minDistance;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java b/src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java
new file mode 100644
index 000000000000..b93c9f89c944
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java
@@ -0,0 +1,127 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class TravelingSalesmanTest {
+
+    // Test Case 1: A simple distance matrix with 4 cities
+    @Test
+    public void testBruteForceSimple() {
+        int[][] distanceMatrix = {{0, 10, 15, 20}, {10, 0, 35, 25}, {15, 35, 0, 30}, {20, 25, 30, 0}};
+        int expectedMinDistance = 80;
+        int result = TravelingSalesman.bruteForce(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    @Test
+    public void testDynamicProgrammingSimple() {
+        int[][] distanceMatrix = {{0, 10, 15, 20}, {10, 0, 35, 25}, {15, 35, 0, 30}, {20, 25, 30, 0}};
+        int expectedMinDistance = 80;
+        int result = TravelingSalesman.dynamicProgramming(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    // Test Case 2: A distance matrix with 3 cities
+    @Test
+    public void testBruteForceThreeCities() {
+        int[][] distanceMatrix = {{0, 10, 15}, {10, 0, 35}, {15, 35, 0}};
+        int expectedMinDistance = 60;
+        int result = TravelingSalesman.bruteForce(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    @Test
+    public void testDynamicProgrammingThreeCities() {
+        int[][] distanceMatrix = {{0, 10, 15}, {10, 0, 35}, {15, 35, 0}};
+        int expectedMinDistance = 60;
+        int result = TravelingSalesman.dynamicProgramming(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    // Test Case 3: A distance matrix with 5 cities (larger input)
+    @Test
+    public void testBruteForceFiveCities() {
+        int[][] distanceMatrix = {{0, 2, 9, 10, 1}, {2, 0, 6, 5, 8}, {9, 6, 0, 4, 3}, {10, 5, 4, 0, 7}, {1, 8, 3, 7, 0}};
+        int expectedMinDistance = 15;
+        int result = TravelingSalesman.bruteForce(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    @Test
+    public void testDynamicProgrammingFiveCities() {
+        int[][] distanceMatrix = {{0, 2, 9, 10, 1}, {2, 0, 6, 5, 8}, {9, 6, 0, 4, 3}, {10, 5, 4, 0, 7}, {1, 8, 3, 7, 0}};
+        int expectedMinDistance = 15;
+        int result = TravelingSalesman.dynamicProgramming(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    // Test Case 4: A distance matrix with 2 cities (simple case)
+    @Test
+    public void testBruteForceTwoCities() {
+        int[][] distanceMatrix = {{0, 1}, {1, 0}};
+        int expectedMinDistance = 2;
+        int result = TravelingSalesman.bruteForce(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    @Test
+    public void testDynamicProgrammingTwoCities() {
+        int[][] distanceMatrix = {{0, 1}, {1, 0}};
+        int expectedMinDistance = 2;
+        int result = TravelingSalesman.dynamicProgramming(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    // Test Case 5: A distance matrix with identical distances
+    @Test
+    public void testBruteForceEqualDistances() {
+        int[][] distanceMatrix = {{0, 10, 10, 10}, {10, 0, 10, 10}, {10, 10, 0, 10}, {10, 10, 10, 0}};
+        int expectedMinDistance = 40;
+        int result = TravelingSalesman.bruteForce(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    @Test
+    public void testDynamicProgrammingEqualDistances() {
+        int[][] distanceMatrix = {{0, 10, 10, 10}, {10, 0, 10, 10}, {10, 10, 0, 10}, {10, 10, 10, 0}};
+        int expectedMinDistance = 40;
+        int result = TravelingSalesman.dynamicProgramming(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    // Test Case 6: A distance matrix with only one city
+    @Test
+    public void testBruteForceOneCity() {
+        int[][] distanceMatrix = {{0}};
+        int expectedMinDistance = 0;
+        int result = TravelingSalesman.bruteForce(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    @Test
+    public void testDynamicProgrammingOneCity() {
+        int[][] distanceMatrix = {{0}};
+        int expectedMinDistance = 0;
+        int result = TravelingSalesman.dynamicProgramming(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    // Test Case 7: Distance matrix with large numbers
+    @Test
+    public void testBruteForceLargeNumbers() {
+        int[][] distanceMatrix = {{0, 1000000, 2000000}, {1000000, 0, 1500000}, {2000000, 1500000, 0}};
+        int expectedMinDistance = 4500000;
+        int result = TravelingSalesman.bruteForce(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+
+    @Test
+    public void testDynamicProgrammingLargeNumbers() {
+        int[][] distanceMatrix = {{0, 1000000, 2000000}, {1000000, 0, 1500000}, {2000000, 1500000, 0}};
+        int expectedMinDistance = 4500000;
+        int result = TravelingSalesman.dynamicProgramming(distanceMatrix);
+        assertEquals(expectedMinDistance, result);
+    }
+}

From 3471bbb5a31ee729bd5a7d6e3d3993edcb598ffa Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 1 Apr 2025 12:10:23 +0000
Subject: [PATCH 0778/1338] Bump org.apache.maven.plugins:maven-surefire-plugin
 from 3.5.2 to 3.5.3 (#6207)

Bumps [org.apache.maven.plugins:maven-surefire-plugin](https://github.com/apache/maven-surefire) from 3.5.2 to 3.5.3.
- [Release notes](https://github.com/apache/maven-surefire/releases)
- [Commits](https://github.com/apache/maven-surefire/compare/surefire-3.5.2...surefire-3.5.3)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-surefire-plugin
  dependency-version: 3.5.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 43c0a2b28627..104506f61b69 100644
--- a/pom.xml
+++ b/pom.xml
@@ -61,7 +61,7 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.5.2</version>
+                <version>3.5.3</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>

From a5a4873b94fbf241f73f6f95d4d40e3349ee0f66 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 1 Apr 2025 14:22:22 +0200
Subject: [PATCH 0779/1338] Bump com.puppycrawl.tools:checkstyle from 10.21.4
 to 10.22.0 (#6208)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.21.4 to 10.22.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.21.4...checkstyle-10.22.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 10.22.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 104506f61b69..42abb4d7c284 100644
--- a/pom.xml
+++ b/pom.xml
@@ -115,7 +115,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.21.4</version>
+                    <version>10.22.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 22098c7d1ef06df65ccfcd33bd17d8ad9783dafc Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 1 Apr 2025 18:54:19 +0200
Subject: [PATCH 0780/1338] style: remove redundant PMD exclusions (#6209)

---
 pmd-exclude.properties | 25 -------------------------
 1 file changed, 25 deletions(-)

diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index 5bf31455e190..1848412c9d30 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -1,29 +1,19 @@
-com.thealgorithms.bitmanipulation.SingleBitOperations=UselessParentheses
 com.thealgorithms.ciphers.AffineCipher=UselessParentheses
-com.thealgorithms.ciphers.ColumnarTranspositionCipher=UnnecessaryFullyQualifiedName
 com.thealgorithms.ciphers.DES=UselessParentheses
-com.thealgorithms.ciphers.HillCipher=UselessParentheses
 com.thealgorithms.ciphers.RSA=UselessParentheses
 com.thealgorithms.conversions.AnyBaseToAnyBase=UselessParentheses
 com.thealgorithms.conversions.AnytoAny=UselessParentheses
-com.thealgorithms.conversions.HexToOct=UselessParentheses
-com.thealgorithms.conversions.IntegerToRoman=UnnecessaryFullyQualifiedName
-com.thealgorithms.datastructures.crdt.LWWElementSet=UselessParentheses
 com.thealgorithms.datastructures.crdt.Pair=UnusedPrivateField
 com.thealgorithms.datastructures.graphs.AStar=UselessParentheses
 com.thealgorithms.datastructures.graphs.AdjacencyMatrixGraph=CollapsibleIfStatements,UnnecessaryFullyQualifiedName,UselessParentheses
 com.thealgorithms.datastructures.graphs.BipartiteGraphDFS=CollapsibleIfStatements
-com.thealgorithms.datastructures.graphs.Kruskal=UselessParentheses
 com.thealgorithms.datastructures.hashmap.hashing.HashMapCuckooHashing=UselessParentheses
 com.thealgorithms.datastructures.heaps.FibonacciHeap=UselessParentheses
-com.thealgorithms.datastructures.heaps.HeapElement=UselessParentheses
 com.thealgorithms.datastructures.heaps.HeapNode=UselessParentheses
 com.thealgorithms.datastructures.lists.DoublyLinkedList=UselessParentheses
 com.thealgorithms.datastructures.lists.SearchSinglyLinkedListRecursion=UselessParentheses
 com.thealgorithms.datastructures.lists.SinglyLinkedList=UnusedLocalVariable
 com.thealgorithms.datastructures.queues.PriorityQueue=UselessParentheses
-com.thealgorithms.datastructures.stacks.NodeStack=UnnecessaryFullyQualifiedName,UnusedFormalParameter
-com.thealgorithms.datastructures.stacks.StackArray=UselessParentheses
 com.thealgorithms.datastructures.trees.CheckBinaryTreeIsValidBST=UselessParentheses
 com.thealgorithms.datastructures.trees.SegmentTree=UselessParentheses
 com.thealgorithms.devutils.nodes.LargeTreeNode=UselessParentheses
@@ -32,9 +22,6 @@ com.thealgorithms.devutils.nodes.SimpleTreeNode=UselessParentheses
 com.thealgorithms.devutils.nodes.TreeNode=UselessParentheses
 com.thealgorithms.divideandconquer.ClosestPair=UnnecessaryFullyQualifiedName,UselessParentheses
 com.thealgorithms.divideandconquer.Point=UselessParentheses
-com.thealgorithms.dynamicprogramming.MatrixChainMultiplication=UselessParentheses
-com.thealgorithms.dynamicprogramming.ShortestSuperSequence=UselessParentheses
-com.thealgorithms.dynamicprogramming.UniquePaths=UnnecessarySemicolon
 com.thealgorithms.dynamicprogramming.WineProblem=UselessParentheses
 com.thealgorithms.maths.BinomialCoefficient=UselessParentheses
 com.thealgorithms.maths.Complex=UselessParentheses
@@ -46,44 +33,32 @@ com.thealgorithms.maths.KaprekarNumbers=UselessParentheses
 com.thealgorithms.maths.KeithNumber=UselessParentheses
 com.thealgorithms.maths.LeonardoNumber=UselessParentheses
 com.thealgorithms.maths.LinearDiophantineEquationsSolver=UselessParentheses
-com.thealgorithms.maths.MatrixUtil=UselessParentheses
 com.thealgorithms.maths.RomanNumeralUtil=UselessParentheses
 com.thealgorithms.maths.SecondMinMax=UselessParentheses
 com.thealgorithms.maths.SecondMinMaxTest=UnnecessaryFullyQualifiedName
 com.thealgorithms.maths.StandardDeviation=UselessParentheses
 com.thealgorithms.maths.SumOfArithmeticSeries=UselessParentheses
 com.thealgorithms.maths.TrinomialTriangle=UselessParentheses
-com.thealgorithms.maths.VampireNumber=CollapsibleIfStatements
 com.thealgorithms.maths.Volume=UselessParentheses
 com.thealgorithms.misc.Sparsity=UselessParentheses
-com.thealgorithms.misc.ThreeSumProblem=UselessParentheses
-com.thealgorithms.misc.WordBoggle=UselessParentheses
 com.thealgorithms.others.CRC16=UselessParentheses
 com.thealgorithms.others.Damm=UnnecessaryFullyQualifiedName
 com.thealgorithms.others.Luhn=UnnecessaryFullyQualifiedName
 com.thealgorithms.others.Mandelbrot=UselessParentheses
-com.thealgorithms.others.MaximumSumOfDistinctSubarraysWithLengthK=CollapsibleIfStatements
 com.thealgorithms.others.MiniMaxAlgorithm=UselessParentheses
 com.thealgorithms.others.PageRank=UselessParentheses
 com.thealgorithms.others.PerlinNoise=UselessParentheses
 com.thealgorithms.others.QueueUsingTwoStacks=UselessParentheses
-com.thealgorithms.others.QueueWithStack=UselessParentheses
 com.thealgorithms.others.Trieac=UselessParentheses
 com.thealgorithms.others.Verhoeff=UnnecessaryFullyQualifiedName
 com.thealgorithms.searches.InterpolationSearch=UselessParentheses
 com.thealgorithms.searches.KMPSearch=UselessParentheses
-com.thealgorithms.searches.LinearSearchThread=EmptyCatchBlock
 com.thealgorithms.searches.RabinKarpAlgorithm=UselessParentheses
 com.thealgorithms.sorts.CircleSort=EmptyControlStatement
-com.thealgorithms.sorts.CombSort=UselessParentheses
 com.thealgorithms.sorts.DutchNationalFlagSort=UselessParentheses
-com.thealgorithms.sorts.LinkListSort=EmptyControlStatement,UnusedLocalVariable
 com.thealgorithms.sorts.MergeSortNoExtraSpace=UselessParentheses
-com.thealgorithms.sorts.PigeonholeSort=UselessParentheses
 com.thealgorithms.sorts.RadixSort=UselessParentheses
 com.thealgorithms.sorts.WiggleSort=UselessParentheses
 com.thealgorithms.stacks.PostfixToInfix=UselessParentheses
 com.thealgorithms.strings.HorspoolSearch=UnnecessaryFullyQualifiedName,UselessParentheses
-com.thealgorithms.strings.MyAtoi=UselessParentheses
 com.thealgorithms.strings.Palindrome=UselessParentheses
-com.thealgorithms.strings.Solution=CollapsibleIfStatements

From 251e9e1902a11436f988228ac09877561e89063f Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 2 Apr 2025 17:51:40 +0200
Subject: [PATCH 0781/1338] refactor: introduce `SinglyLinkedListNode` (#6210)

---
 .../lists/CountSinglyLinkedListRecursion.java |   2 +-
 .../lists/MergeSortedSinglyLinkedList.java    |   8 +-
 .../lists/QuickSortLinkedList.java            |  20 ++--
 .../datastructures/lists/ReverseKGroup.java   |  20 ++--
 .../lists/RotateSinglyLinkedLists.java        |   4 +-
 .../SearchSinglyLinkedListRecursion.java      |   2 +-
 .../lists/SinglyLinkedList.java               | 102 ++++++------------
 .../lists/SinglyLinkedListNode.java           |  34 ++++++
 .../lists/ReverseKGroupTest.java              |  32 +++---
 .../lists/RotateSinglyLinkedListsTest.java    |  40 +++----
 .../lists/SinglyLinkedListTest.java           |  40 +++----
 11 files changed, 149 insertions(+), 155 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedListNode.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java b/src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java
index 4c1ffe9d3ea4..b58d51e7e5fe 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java
@@ -12,7 +12,7 @@ public class CountSinglyLinkedListRecursion extends SinglyLinkedList {
      * @param head the head node of the list segment being counted.
      * @return the count of nodes from the given head node onward.
      */
-    private int countRecursion(Node head) {
+    private int countRecursion(SinglyLinkedListNode head) {
         return head == null ? 0 : 1 + countRecursion(head.next);
     }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java
index a16b202c4505..4e99642fccd8 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java
@@ -42,12 +42,12 @@ public static SinglyLinkedList merge(SinglyLinkedList listA, SinglyLinkedList li
             throw new NullPointerException("Input lists must not be null.");
         }
 
-        Node headA = listA.getHead();
-        Node headB = listB.getHead();
+        SinglyLinkedListNode headA = listA.getHead();
+        SinglyLinkedListNode headB = listB.getHead();
         int size = listA.size() + listB.size();
 
-        Node head = new Node();
-        Node tail = head;
+        SinglyLinkedListNode head = new SinglyLinkedListNode();
+        SinglyLinkedListNode tail = head;
         while (headA != null && headB != null) {
             if (headA.value <= headB.value) {
                 tail.next = headA;
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java
index 08fe674b47f4..f018781ada70 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java
@@ -105,7 +105,7 @@
 public class QuickSortLinkedList {
 
     private final SinglyLinkedList list; // The linked list to be sorted
-    private Node head; // Head of the list
+    private SinglyLinkedListNode head; // Head of the list
 
     /**
      * Constructor that initializes the QuickSortLinkedList with a given linked list.
@@ -136,19 +136,19 @@ public void sortList() {
      * @param head The head node of the list to sort
      * @return The head node of the sorted linked list
      */
-    private Node sortList(Node head) {
+    private SinglyLinkedListNode sortList(SinglyLinkedListNode head) {
         if (head == null || head.next == null) {
             return head;
         }
 
-        Node pivot = head;
+        SinglyLinkedListNode pivot = head;
         head = head.next;
         pivot.next = null;
 
-        Node lessHead = new Node();
-        Node lessTail = lessHead;
-        Node greaterHead = new Node();
-        Node greaterTail = greaterHead;
+        SinglyLinkedListNode lessHead = new SinglyLinkedListNode();
+        SinglyLinkedListNode lessTail = lessHead;
+        SinglyLinkedListNode greaterHead = new SinglyLinkedListNode();
+        SinglyLinkedListNode greaterTail = greaterHead;
 
         while (head != null) {
             if (head.value < pivot.value) {
@@ -164,14 +164,14 @@ private Node sortList(Node head) {
         lessTail.next = null;
         greaterTail.next = null;
 
-        Node sortedLess = sortList(lessHead.next);
-        Node sortedGreater = sortList(greaterHead.next);
+        SinglyLinkedListNode sortedLess = sortList(lessHead.next);
+        SinglyLinkedListNode sortedGreater = sortList(greaterHead.next);
 
         if (sortedLess == null) {
             pivot.next = sortedGreater;
             return pivot;
         } else {
-            Node current = sortedLess;
+            SinglyLinkedListNode current = sortedLess;
             while (current.next != null) {
                 current = current.next;
             }
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java b/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
index c9a5c1df9870..9b9464d388b5 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java
@@ -14,10 +14,10 @@
  * </p>
  * <p>
  * The implementation contains:
- * - {@code length(Node head)}: A method to calculate the length of the linked list.
- * - {@code reverse(Node head, int count, int k)}: A helper method that reverses the nodes
+ * - {@code length(SinglyLinkedListNode head)}: A method to calculate the length of the linked list.
+ * - {@code reverse(SinglyLinkedListNode head, int count, int k)}: A helper method that reverses the nodes
  *   in the linked list in groups of k.
- * - {@code reverseKGroup(Node head, int k)}: The main method that initiates the reversal
+ * - {@code reverseKGroup(SinglyLinkedListNode head, int k)}: The main method that initiates the reversal
  *   process by calling the reverse method.
  * </p>
  * <p>
@@ -38,8 +38,8 @@ public class ReverseKGroup {
      * @param head The head node of the linked list.
      * @return The total number of nodes in the linked list.
      */
-    public int length(Node head) {
-        Node curr = head;
+    public int length(SinglyLinkedListNode head) {
+        SinglyLinkedListNode curr = head;
         int count = 0;
         while (curr != null) {
             curr = curr.next;
@@ -56,14 +56,14 @@ public int length(Node head) {
      * @param k The size of the group to reverse.
      * @return The new head of the reversed linked list segment.
      */
-    public Node reverse(Node head, int count, int k) {
+    public SinglyLinkedListNode reverse(SinglyLinkedListNode head, int count, int k) {
         if (count < k) {
             return head;
         }
-        Node prev = null;
+        SinglyLinkedListNode prev = null;
         int count1 = 0;
-        Node curr = head;
-        Node next = null;
+        SinglyLinkedListNode curr = head;
+        SinglyLinkedListNode next = null;
         while (curr != null && count1 < k) {
             next = curr.next;
             curr.next = prev;
@@ -85,7 +85,7 @@ public Node reverse(Node head, int count, int k) {
      * @param k The size of the group to reverse.
      * @return The head of the modified linked list after reversal.
      */
-    public Node reverseKGroup(Node head, int k) {
+    public SinglyLinkedListNode reverseKGroup(SinglyLinkedListNode head, int k) {
         int count = length(head);
         return reverse(head, count, k);
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java b/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java
index 7676cc343653..47ee5397097c 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java
@@ -38,12 +38,12 @@ public class RotateSinglyLinkedLists {
      * @param k The number of positions to rotate the list to the right.
      * @return The head of the rotated linked list.
      */
-    public Node rotateRight(Node head, int k) {
+    public SinglyLinkedListNode rotateRight(SinglyLinkedListNode head, int k) {
         if (head == null || head.next == null || k == 0) {
             return head;
         }
 
-        Node curr = head;
+        SinglyLinkedListNode curr = head;
         int len = 1;
         while (curr.next != null) {
             curr = curr.next;
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java b/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java
index a40e9b2a1a66..4ac2de422595 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java
@@ -30,7 +30,7 @@ public class SearchSinglyLinkedListRecursion extends SinglyLinkedList {
      * @param key the integer value to be searched for.
      * @return {@code true} if the value `key` is present in the list; otherwise, {@code false}.
      */
-    private boolean searchRecursion(Node node, int key) {
+    private boolean searchRecursion(SinglyLinkedListNode node, int key) {
         return (node != null && (node.value == key || searchRecursion(node.next, key)));
     }
 
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
index eb6cdf48f58b..ff4af4437cc7 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java
@@ -12,7 +12,7 @@ public class SinglyLinkedList implements Iterable<Integer> {
     /**
      * Head refer to the front of the list
      */
-    private Node head;
+    private SinglyLinkedListNode head;
 
     /**
      * Size of SinglyLinkedList
@@ -33,7 +33,7 @@ public SinglyLinkedList() {
      * @param head the head node of list
      * @param size the size of list
      */
-    public SinglyLinkedList(Node head, int size) {
+    public SinglyLinkedList(SinglyLinkedListNode head, int size) {
         this.head = head;
         this.size = size;
     }
@@ -44,8 +44,8 @@ public SinglyLinkedList(Node head, int size) {
      *
      */
     public boolean detectLoop() {
-        Node currentNodeFast = head;
-        Node currentNodeSlow = head;
+        SinglyLinkedListNode currentNodeFast = head;
+        SinglyLinkedListNode currentNodeSlow = head;
         while (currentNodeFast != null && currentNodeFast.next != null) {
             currentNodeFast = currentNodeFast.next.next;
             currentNodeSlow = currentNodeSlow.next;
@@ -61,12 +61,12 @@ public boolean detectLoop() {
      * If the length of the list is even then return item number length/2
      * @return middle node of the list
      */
-    public Node middle() {
+    public SinglyLinkedListNode middle() {
         if (head == null) {
             return null;
         }
-        Node firstCounter = head;
-        Node secondCounter = firstCounter.next;
+        SinglyLinkedListNode firstCounter = head;
+        SinglyLinkedListNode secondCounter = firstCounter.next;
         while (secondCounter != null && secondCounter.next != null) {
             firstCounter = firstCounter.next;
             secondCounter = secondCounter.next.next;
@@ -82,15 +82,15 @@ public void swapNodes(int valueFirst, int valueSecond) {
         if (valueFirst == valueSecond) {
             return;
         }
-        Node previousA = null;
-        Node currentA = head;
+        SinglyLinkedListNode previousA = null;
+        SinglyLinkedListNode currentA = head;
         while (currentA != null && currentA.value != valueFirst) {
             previousA = currentA;
             currentA = currentA.next;
         }
 
-        Node previousB = null;
-        Node currentB = head;
+        SinglyLinkedListNode previousB = null;
+        SinglyLinkedListNode currentB = head;
         while (currentB != null && currentB.value != valueSecond) {
             previousB = currentB;
             currentB = currentB.next;
@@ -117,7 +117,7 @@ public void swapNodes(int valueFirst, int valueSecond) {
         }
         // Swap next pointer
 
-        Node temp = currentA.next;
+        var temp = currentA.next;
         currentA.next = currentB.next;
         currentB.next = temp;
     }
@@ -126,12 +126,12 @@ public void swapNodes(int valueFirst, int valueSecond) {
      * Reverse a singly linked list[Iterative] from a given node till the end
      *
      */
-    public Node reverseListIter(Node node) {
-        Node prev = null;
-        Node curr = node;
+    public SinglyLinkedListNode reverseListIter(SinglyLinkedListNode node) {
+        SinglyLinkedListNode prev = null;
+        SinglyLinkedListNode curr = node;
 
         while (curr != null && curr.next != null) {
-            Node next = curr.next;
+            var next = curr.next;
             curr.next = prev;
             prev = curr;
             curr = next;
@@ -149,13 +149,13 @@ public Node reverseListIter(Node node) {
      * Reverse a singly linked list[Recursive] from a given node till the end
      *
      */
-    public Node reverseListRec(Node head) {
+    public SinglyLinkedListNode reverseListRec(SinglyLinkedListNode head) {
         if (head == null || head.next == null) {
             return head;
         }
 
-        Node prev = null;
-        Node h2 = reverseListRec(head.next);
+        SinglyLinkedListNode prev = null;
+        SinglyLinkedListNode h2 = reverseListRec(head.next);
 
         head.next.next = head;
         head.next = prev;
@@ -167,7 +167,7 @@ public Node reverseListRec(Node head) {
      * Clear all nodes in the list
      */
     public void clear() {
-        Node cur = head;
+        SinglyLinkedListNode cur = head;
         while (cur != null) {
             cur = cur.next;
         }
@@ -198,7 +198,7 @@ public int size() {
      *
      * @return head of the list.
      */
-    public Node getHead() {
+    public SinglyLinkedListNode getHead() {
         return head;
     }
 
@@ -206,7 +206,7 @@ public Node getHead() {
      * Set head of the list.
      *
      */
-    public void setHead(Node head) {
+    public void setHead(SinglyLinkedListNode head) {
         this.head = head;
     }
 
@@ -249,10 +249,10 @@ public String toString() {
     }
 
     public void deleteDuplicates() {
-        Node pred = head;
+        SinglyLinkedListNode pred = head;
         // predecessor = the node
         // having sublist of its duplicates
-        Node newHead = head;
+        SinglyLinkedListNode newHead = head;
         while (newHead != null) {
             // if it's a beginning of duplicates sublist
             // skip all duplicates
@@ -273,7 +273,7 @@ public void deleteDuplicates() {
     }
 
     public void print() {
-        Node temp = head;
+        SinglyLinkedListNode temp = head;
         while (temp != null && temp.next != null) {
             System.out.print(temp.value + "->");
             temp = temp.next;
@@ -310,7 +310,7 @@ public void insert(int data) {
      */
     public void insertNth(int data, int position) {
         checkBounds(position, 0, size);
-        Node newNode = new Node(data);
+        SinglyLinkedListNode newNode = new SinglyLinkedListNode(data);
         if (head == null) {
             /* the list is empty */
             head = newNode;
@@ -325,7 +325,7 @@ public void insertNth(int data, int position) {
             return;
         }
 
-        Node cur = head;
+        SinglyLinkedListNode cur = head;
         for (int i = 0; i < position - 1; ++i) {
             cur = cur.next;
         }
@@ -359,7 +359,7 @@ public void deleteNth(int position) {
             size--;
             return;
         }
-        Node cur = head;
+        SinglyLinkedListNode cur = head;
         for (int i = 0; i < position - 1; ++i) {
             cur = cur.next;
         }
@@ -376,7 +376,7 @@ public void deleteNth(int position) {
      */
     public int getNth(int index) {
         checkBounds(index, 0, size - 1);
-        Node cur = head;
+        SinglyLinkedListNode cur = head;
         for (int i = 0; i < index; ++i) {
             cur = cur.next;
         }
@@ -440,7 +440,7 @@ public static void main(String[] arg) {
         }
 
         SinglyLinkedList instance = new SinglyLinkedList();
-        Node head = new Node(0, new Node(2, new Node(3, new Node(3, new Node(4)))));
+        SinglyLinkedListNode head = new SinglyLinkedListNode(0, new SinglyLinkedListNode(2, new SinglyLinkedListNode(3, new SinglyLinkedListNode(3, new SinglyLinkedListNode(4)))));
         instance.setHead(head);
         instance.deleteDuplicates();
         instance.print();
@@ -452,7 +452,7 @@ public Iterator<Integer> iterator() {
     }
 
     private class SinglyLinkedListIterator implements Iterator<Integer> {
-        private Node current;
+        private SinglyLinkedListNode current;
 
         SinglyLinkedListIterator() {
             current = head;
@@ -474,43 +474,3 @@ public Integer next() {
         }
     }
 }
-
-/**
- * This class is the nodes of the SinglyLinked List. They consist of a value and
- * a pointer to the node after them.
- */
-class Node {
-
-    /**
-     * The value of the node
-     */
-    int value;
-
-    /**
-     * Point to the next node
-     */
-    Node next;
-
-    Node() {
-    }
-
-    /**
-     * Constructor
-     *
-     * @param value Value to be put in the node
-     */
-    Node(int value) {
-        this(value, null);
-    }
-
-    /**
-     * Constructor
-     *
-     * @param value Value to be put in the node
-     * @param next Reference to the next node
-     */
-    Node(int value, Node next) {
-        this.value = value;
-        this.next = next;
-    }
-}
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedListNode.java b/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedListNode.java
new file mode 100644
index 000000000000..d0a06369215a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedListNode.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.datastructures.lists;
+
+/**
+ * This class is the nodes of the SinglyLinked List. They consist of a value and
+ * a pointer to the node after them.
+ */
+class SinglyLinkedListNode {
+
+    int value;
+    SinglyLinkedListNode next = null;
+
+    SinglyLinkedListNode() {
+    }
+
+    /**
+     * Constructor
+     *
+     * @param value Value to be put in the node
+     */
+    SinglyLinkedListNode(int value) {
+        this(value, null);
+    }
+
+    /**
+     * Constructor
+     *
+     * @param value Value to be put in the node
+     * @param next Reference to the next node
+     */
+    SinglyLinkedListNode(int value, SinglyLinkedListNode next) {
+        this.value = value;
+        this.next = next;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java b/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
index b2db478f692c..76b7ab063de4 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java
@@ -20,8 +20,8 @@ public void testReverseKGroupWithEmptyList() {
     @Test
     public void testReverseKGroupWithSingleNodeList() {
         ReverseKGroup reverser = new ReverseKGroup();
-        Node singleNode = new Node(5);
-        Node result = reverser.reverseKGroup(singleNode, 2);
+        SinglyLinkedListNode singleNode = new SinglyLinkedListNode(5);
+        SinglyLinkedListNode result = reverser.reverseKGroup(singleNode, 2);
         assertEquals(5, result.value);
         assertNull(result.next);
     }
@@ -31,15 +31,15 @@ public void testReverseKGroupWithKEqualTo2() {
         ReverseKGroup reverser = new ReverseKGroup();
 
         // Create a list with multiple elements (1 -> 2 -> 3 -> 4 -> 5)
-        Node head;
-        head = new Node(1);
-        head.next = new Node(2);
-        head.next.next = new Node(3);
-        head.next.next.next = new Node(4);
-        head.next.next.next.next = new Node(5);
+        SinglyLinkedListNode head;
+        head = new SinglyLinkedListNode(1);
+        head.next = new SinglyLinkedListNode(2);
+        head.next.next = new SinglyLinkedListNode(3);
+        head.next.next.next = new SinglyLinkedListNode(4);
+        head.next.next.next.next = new SinglyLinkedListNode(5);
 
         // Test reverse with k=2
-        Node result1 = reverser.reverseKGroup(head, 2);
+        SinglyLinkedListNode result1 = reverser.reverseKGroup(head, 2);
         assertEquals(2, result1.value);
         assertEquals(1, result1.next.value);
         assertEquals(4, result1.next.next.value);
@@ -53,15 +53,15 @@ public void testReverseKGroupWithKEqualTo3() {
         ReverseKGroup reverser = new ReverseKGroup();
 
         // Create a list with multiple elements (1 -> 2 -> 3 -> 4 -> 5)
-        Node head;
-        head = new Node(1);
-        head.next = new Node(2);
-        head.next.next = new Node(3);
-        head.next.next.next = new Node(4);
-        head.next.next.next.next = new Node(5);
+        SinglyLinkedListNode head;
+        head = new SinglyLinkedListNode(1);
+        head.next = new SinglyLinkedListNode(2);
+        head.next.next = new SinglyLinkedListNode(3);
+        head.next.next.next = new SinglyLinkedListNode(4);
+        head.next.next.next.next = new SinglyLinkedListNode(5);
 
         // Test reverse with k=3
-        Node result = reverser.reverseKGroup(head, 3);
+        SinglyLinkedListNode result = reverser.reverseKGroup(head, 3);
         assertEquals(3, result.value);
         assertEquals(2, result.next.value);
         assertEquals(1, result.next.next.value);
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java b/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
index 70c0dfccafa4..c476ad1b0203 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java
@@ -14,24 +14,24 @@ public class RotateSinglyLinkedListsTest {
     private final RotateSinglyLinkedLists rotator = new RotateSinglyLinkedLists();
 
     // Helper method to create a linked list from an array of values
-    private Node createLinkedList(int[] values) {
+    private SinglyLinkedListNode createLinkedList(int[] values) {
         if (values.length == 0) {
             return null;
         }
 
-        Node head = new Node(values[0]);
-        Node current = head;
+        SinglyLinkedListNode head = new SinglyLinkedListNode(values[0]);
+        SinglyLinkedListNode current = head;
         for (int i = 1; i < values.length; i++) {
-            current.next = new Node(values[i]);
+            current.next = new SinglyLinkedListNode(values[i]);
             current = current.next;
         }
         return head;
     }
 
     // Helper method to convert a linked list to a string for easy comparison
-    private String linkedListToString(Node head) {
+    private String linkedListToString(SinglyLinkedListNode head) {
         StringBuilder sb = new StringBuilder();
-        Node current = head;
+        SinglyLinkedListNode current = head;
         while (current != null) {
             sb.append(current.value);
             if (current.next != null) {
@@ -51,55 +51,55 @@ public void testRotateRightEmptyList() {
     @Test
     public void testRotateRightSingleNodeList() {
         // Rotate a list with a single element
-        Node singleNode = new Node(5);
-        Node rotatedSingleNode = rotator.rotateRight(singleNode, 3);
+        SinglyLinkedListNode singleNode = new SinglyLinkedListNode(5);
+        SinglyLinkedListNode rotatedSingleNode = rotator.rotateRight(singleNode, 3);
         assertEquals("5", linkedListToString(rotatedSingleNode));
     }
 
     @Test
     public void testRotateRightMultipleElementsList() {
         // Rotate a list with multiple elements (rotate by 2)
-        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5});
-        Node rotated = rotator.rotateRight(head, 2);
+        SinglyLinkedListNode head = createLinkedList(new int[] {1, 2, 3, 4, 5});
+        SinglyLinkedListNode rotated = rotator.rotateRight(head, 2);
         assertEquals("4 -> 5 -> 1 -> 2 -> 3", linkedListToString(rotated));
     }
 
     @Test
     public void testRotateRightFullRotation() {
         // Rotate by more than the length of the list
-        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5});
-        Node rotated = rotator.rotateRight(head, 7);
+        SinglyLinkedListNode head = createLinkedList(new int[] {1, 2, 3, 4, 5});
+        SinglyLinkedListNode rotated = rotator.rotateRight(head, 7);
         assertEquals("4 -> 5 -> 1 -> 2 -> 3", linkedListToString(rotated));
     }
 
     @Test
     public void testRotateRightZeroRotation() {
         // Rotate a list by k = 0 (no rotation)
-        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5});
-        Node rotated = rotator.rotateRight(head, 0);
+        SinglyLinkedListNode head = createLinkedList(new int[] {1, 2, 3, 4, 5});
+        SinglyLinkedListNode rotated = rotator.rotateRight(head, 0);
         assertEquals("1 -> 2 -> 3 -> 4 -> 5", linkedListToString(rotated));
     }
 
     @Test
     public void testRotateRightByListLength() {
         // Rotate a list by k equal to list length (no change)
-        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5});
-        Node rotated = rotator.rotateRight(head, 5);
+        SinglyLinkedListNode head = createLinkedList(new int[] {1, 2, 3, 4, 5});
+        SinglyLinkedListNode rotated = rotator.rotateRight(head, 5);
         assertEquals("1 -> 2 -> 3 -> 4 -> 5", linkedListToString(rotated));
     }
 
     @Test
     public void testRotateRightByMultipleOfListLength() {
-        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5});
-        Node rotated = rotator.rotateRight(head, 10); // k = 2 * list length
+        SinglyLinkedListNode head = createLinkedList(new int[] {1, 2, 3, 4, 5});
+        SinglyLinkedListNode rotated = rotator.rotateRight(head, 10); // k = 2 * list length
         assertEquals("1 -> 2 -> 3 -> 4 -> 5", linkedListToString(rotated));
     }
 
     @Test
     public void testRotateRightLongerList() {
         // Rotate a longer list by a smaller k
-        Node head = createLinkedList(new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9});
-        Node rotated = rotator.rotateRight(head, 4);
+        SinglyLinkedListNode head = createLinkedList(new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9});
+        SinglyLinkedListNode rotated = rotator.rotateRight(head, 4);
         assertEquals("6 -> 7 -> 8 -> 9 -> 1 -> 2 -> 3 -> 4 -> 5", linkedListToString(rotated));
     }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
index a47434083cdb..f80c6b5055f0 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
@@ -18,9 +18,9 @@ public class SinglyLinkedListTest {
      * @return linked list with pre-defined number of nodes
      */
     private SinglyLinkedList createSampleList(int length) {
-        List<Node> nodeList = new ArrayList<>();
+        List<SinglyLinkedListNode> nodeList = new ArrayList<>();
         for (int i = 1; i <= length; i++) {
-            Node node = new Node(i);
+            SinglyLinkedListNode node = new SinglyLinkedListNode(i);
             nodeList.add(node);
         }
 
@@ -34,10 +34,10 @@ private SinglyLinkedList createSampleList(int length) {
     @Test
     void detectLoop() {
         // List has cycle
-        Node firstNode = new Node(1);
-        Node secondNode = new Node(2);
-        Node thirdNode = new Node(3);
-        Node fourthNode = new Node(4);
+        SinglyLinkedListNode firstNode = new SinglyLinkedListNode(1);
+        SinglyLinkedListNode secondNode = new SinglyLinkedListNode(2);
+        SinglyLinkedListNode thirdNode = new SinglyLinkedListNode(3);
+        SinglyLinkedListNode fourthNode = new SinglyLinkedListNode(4);
 
         firstNode.next = secondNode;
         secondNode.next = thirdNode;
@@ -112,13 +112,13 @@ void reverseList() {
 
         // Reversing the LinkedList using reverseList() method and storing the head of the reversed
         // linkedlist in a head node The reversed linkedlist will be 4->3->2->1->null
-        Node head = list.reverseListIter(list.getHead());
+        SinglyLinkedListNode head = list.reverseListIter(list.getHead());
 
         // Recording the Nodes after reversing the LinkedList
-        Node firstNode = head; // 4
-        Node secondNode = firstNode.next; // 3
-        Node thirdNode = secondNode.next; // 2
-        Node fourthNode = thirdNode.next; // 1
+        SinglyLinkedListNode firstNode = head; // 4
+        SinglyLinkedListNode secondNode = firstNode.next; // 3
+        SinglyLinkedListNode thirdNode = secondNode.next; // 2
+        SinglyLinkedListNode fourthNode = thirdNode.next; // 1
 
         // Checking whether the LinkedList is reversed or not by comparing the original list and
         // reversed list nodes
@@ -134,10 +134,10 @@ void reverseList() {
     void reverseListNullPointer() {
         // Creating a linkedlist with first node assigned to null
         SinglyLinkedList list = new SinglyLinkedList();
-        Node first = list.getHead();
+        SinglyLinkedListNode first = list.getHead();
 
         // Reversing the linkedlist
-        Node head = list.reverseListIter(first);
+        SinglyLinkedListNode head = list.reverseListIter(first);
 
         // checking whether the method works fine if the input is null
         assertEquals(head, first);
@@ -151,10 +151,10 @@ void reverseListTest() {
 
         // Reversing the LinkedList using reverseList() method and storing the head of the reversed
         // linkedlist in a head node
-        Node head = list.reverseListIter(list.getHead());
+        SinglyLinkedListNode head = list.reverseListIter(list.getHead());
 
         // Storing the head in a temp variable, so that we cannot loose the track of head
-        Node temp = head;
+        SinglyLinkedListNode temp = head;
 
         int i = 20; // This is for the comparison of values of nodes of the reversed linkedlist
         // Checking whether the reverseList() method performed its task
@@ -171,7 +171,7 @@ void recursiveReverseList() {
         SinglyLinkedList list = createSampleList(5);
 
         // Reversing the linked list using reverseList() method
-        Node head = list.reverseListRec(list.getHead());
+        SinglyLinkedListNode head = list.reverseListRec(list.getHead());
 
         // Check if the reversed list is: 5 -> 4 -> 3 -> 2 -> 1
         assertEquals(5, head.value);
@@ -185,10 +185,10 @@ void recursiveReverseList() {
     void recursiveReverseListNullPointer() {
         // Create an empty linked list
         SinglyLinkedList list = new SinglyLinkedList();
-        Node first = list.getHead();
+        SinglyLinkedListNode first = list.getHead();
 
         // Reversing the empty linked list
-        Node head = list.reverseListRec(first);
+        SinglyLinkedListNode head = list.reverseListRec(first);
 
         // Check if the head remains the same (null)
         assertNull(head);
@@ -200,11 +200,11 @@ void recursiveReverseListTest() {
         SinglyLinkedList list = createSampleList(20);
 
         // Reversing the linked list using reverseList() method
-        Node head = list.reverseListRec(list.getHead());
+        SinglyLinkedListNode head = list.reverseListRec(list.getHead());
 
         // Check if the reversed list has the correct values
         int i = 20;
-        Node temp = head;
+        SinglyLinkedListNode temp = head;
         while (temp != null && i > 0) {
             assertEquals(i, temp.value);
             temp = temp.next;

From 93e853575c98fa6c352097ffc21cb7baa5da3299 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 2 Apr 2025 21:48:08 +0000
Subject: [PATCH 0782/1338] Bump org.jacoco:jacoco-maven-plugin from 0.8.12 to
 0.8.13 (#6211)

Bumps [org.jacoco:jacoco-maven-plugin](https://github.com/jacoco/jacoco) from 0.8.12 to 0.8.13.
- [Release notes](https://github.com/jacoco/jacoco/releases)
- [Commits](https://github.com/jacoco/jacoco/compare/v0.8.12...v0.8.13)

---
updated-dependencies:
- dependency-name: org.jacoco:jacoco-maven-plugin
  dependency-version: 0.8.13
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 42abb4d7c284..b98380c73f7b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -85,7 +85,7 @@
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>
-                <version>0.8.12</version>
+                <version>0.8.13</version>
                 <executions>
                     <execution>
                         <goals>

From c3d65e00cd9cf1a0e04aa86df8cba457496e1bbb Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 2 Apr 2025 21:52:04 +0000
Subject: [PATCH 0783/1338] Bump com.puppycrawl.tools:checkstyle from 10.22.0
 to 10.23.0 (#6212)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.22.0 to 10.23.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.22.0...checkstyle-10.23.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 10.23.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b98380c73f7b..c644c7809884 100644
--- a/pom.xml
+++ b/pom.xml
@@ -115,7 +115,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.22.0</version>
+                    <version>10.23.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 2570a996648c2244b9b89196a4faf4710439c4ff Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 5 Apr 2025 15:24:23 +0200
Subject: [PATCH 0784/1338] Bump org.mockito:mockito-core from 5.16.1 to 5.17.0
 (#6213)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.16.1 to 5.17.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.16.1...v5.17.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.17.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index c644c7809884..3a38f08ad594 100644
--- a/pom.xml
+++ b/pom.xml
@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.16.1</version>
+            <version>5.17.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From f53bc0080baf02209a176b12895f4f876502212d Mon Sep 17 00:00:00 2001
From: cureprotocols <healnet@proton.me>
Date: Mon, 7 Apr 2025 14:58:44 -0600
Subject: [PATCH 0785/1338] Add ReservoirSampling algorithm to randomized
 module (#6204)

---
 .../randomized/ReservoirSampling.java         | 55 +++++++++++++++++++
 .../randomized/ReservoirSamplingTest.java     | 45 +++++++++++++++
 2 files changed, 100 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/randomized/ReservoirSampling.java
 create mode 100644 src/test/java/com/thealgorithms/randomized/ReservoirSamplingTest.java

diff --git a/src/main/java/com/thealgorithms/randomized/ReservoirSampling.java b/src/main/java/com/thealgorithms/randomized/ReservoirSampling.java
new file mode 100644
index 000000000000..05e70f635055
--- /dev/null
+++ b/src/main/java/com/thealgorithms/randomized/ReservoirSampling.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.randomized;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+/**
+ * Reservoir Sampling Algorithm
+ *
+ * Use Case:
+ * - Efficient for selecting k random items from a stream of unknown size
+ * - Used in streaming systems, big data, and memory-limited environments
+ *
+ * Time Complexity: O(n)
+ * Space Complexity: O(k)
+ *
+ * @author Michael Alexander Montoya (@cureprotocols)
+ * @see <a href="https://en.wikipedia.org/wiki/Reservoir_sampling">Reservoir Sampling - Wikipedia</a>
+ */
+public final class ReservoirSampling {
+
+    // Prevent instantiation of utility class
+    private ReservoirSampling() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    /**
+     * Selects k random elements from a stream using reservoir sampling.
+     *
+     * @param stream     The input stream as an array of integers.
+     * @param sampleSize The number of elements to sample.
+     * @return A list containing k randomly selected elements.
+     */
+    public static List<Integer> sample(int[] stream, int sampleSize) {
+        if (sampleSize > stream.length) {
+            throw new IllegalArgumentException("Sample size cannot exceed stream size.");
+        }
+
+        List<Integer> reservoir = new ArrayList<>(sampleSize);
+        Random rand = new Random();
+
+        for (int i = 0; i < stream.length; i++) {
+            if (i < sampleSize) {
+                reservoir.add(stream[i]);
+            } else {
+                int j = rand.nextInt(i + 1);
+                if (j < sampleSize) {
+                    reservoir.set(j, stream[i]);
+                }
+            }
+        }
+
+        return reservoir;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/randomized/ReservoirSamplingTest.java b/src/test/java/com/thealgorithms/randomized/ReservoirSamplingTest.java
new file mode 100644
index 000000000000..0c6061fcde2a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/randomized/ReservoirSamplingTest.java
@@ -0,0 +1,45 @@
+package com.thealgorithms.randomized;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class ReservoirSamplingTest {
+
+    @Test
+    public void testSampleSizeEqualsStreamLength() {
+        int[] stream = {1, 2, 3, 4, 5};
+        int sampleSize = 5;
+
+        List<Integer> result = ReservoirSampling.sample(stream, sampleSize);
+
+        assertEquals(sampleSize, result.size());
+        assertTrue(Arrays.stream(stream).allMatch(result::contains));
+    }
+
+    @Test
+    public void testSampleSizeLessThanStreamLength() {
+        int[] stream = {10, 20, 30, 40, 50, 60};
+        int sampleSize = 3;
+
+        List<Integer> result = ReservoirSampling.sample(stream, sampleSize);
+
+        assertEquals(sampleSize, result.size());
+        for (int value : result) {
+            assertTrue(Arrays.stream(stream).anyMatch(x -> x == value));
+        }
+    }
+
+    @Test
+    public void testSampleSizeGreaterThanStreamLengthThrowsException() {
+        int[] stream = {1, 2, 3};
+
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> ReservoirSampling.sample(stream, 5));
+
+        assertEquals("Sample size cannot exceed stream size.", exception.getMessage());
+    }
+}

From ce6e734ddee4fb9c4298cb59a0f97f11ddc41af2 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 12 Apr 2025 11:20:40 +0300
Subject: [PATCH 0786/1338] Bump org.junit:junit-bom from 5.12.1 to 5.12.2
 (#6217)

---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 3a38f08ad594..62851d2f55d2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.12.1</version>
+                <version>5.12.2</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From c8177e346f5cf3697d87ab435e370dcc7ef1f441 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 15 Apr 2025 00:17:12 +0200
Subject: [PATCH 0787/1338] Bump DoozyX/clang-format-lint-action from 0.18 to
 0.20 in /.github/workflows (#6223)

Bump DoozyX/clang-format-lint-action in /.github/workflows

Bumps [DoozyX/clang-format-lint-action](https://github.com/doozyx/clang-format-lint-action) from 0.18 to 0.20.
- [Release notes](https://github.com/doozyx/clang-format-lint-action/releases)
- [Commits](https://github.com/doozyx/clang-format-lint-action/compare/v0.18...v0.20)

---
updated-dependencies:
- dependency-name: DoozyX/clang-format-lint-action
  dependency-version: '0.20'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/clang-format-lint.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/clang-format-lint.yml b/.github/workflows/clang-format-lint.yml
index 588c05e42e8f..dac697511de1 100644
--- a/.github/workflows/clang-format-lint.yml
+++ b/.github/workflows/clang-format-lint.yml
@@ -9,7 +9,7 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-    - uses: DoozyX/clang-format-lint-action@v0.18
+    - uses: DoozyX/clang-format-lint-action@v0.20
       with:
         source: './src'
         extensions: 'java'

From ad5e496b0c105c6b4e16b8a9547473c51be85096 Mon Sep 17 00:00:00 2001
From: Vusal Huseynov <87518350+huseynovvusal@users.noreply.github.com>
Date: Tue, 15 Apr 2025 17:08:45 +0400
Subject: [PATCH 0788/1338] Add LongestIncreasingSubsequenceNLogN (#6221)

---
 .../LongestIncreasingSubsequenceNLogN.java    | 75 +++++++++++++++++++
 ...LongestIncreasingSubsequenceNLogNTest.java | 22 ++++++
 2 files changed, 97 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogN.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogNTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogN.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogN.java
new file mode 100644
index 000000000000..7bc0855e0566
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogN.java
@@ -0,0 +1,75 @@
+package com.thealgorithms.dynamicprogramming;
+
+/**
+ * Implementation of the Longest Increasing Subsequence (LIS) problem using
+ * an O(n log n) dynamic programming solution enhanced with binary search.
+ *
+ * @author Vusal Huseynov (https://github.com/huseynovvusal)
+ */
+public final class LongestIncreasingSubsequenceNLogN {
+    private LongestIncreasingSubsequenceNLogN() {
+    }
+
+    /**
+     * Finds the index of the smallest element in the array that is greater than
+     * or equal to the target using binary search. The search is restricted to
+     * the first `size` elements of the array.
+     *
+     * @param arr    The array to search in (assumed to be sorted up to `size`).
+     * @param size   The number of valid elements in the array.
+     * @param target The target value to find the lower bound for.
+     * @return The index of the lower bound.
+     */
+    private static int lowerBound(int[] arr, int target, int size) {
+        int l = 0;
+        int r = size;
+
+        while (l < r) {
+            int mid = l + (r - l) / 2;
+
+            if (target > arr[mid]) {
+                // Move right if target is greater than mid element
+                l = mid + 1;
+            } else {
+                // Move left if target is less than or equal to mid element
+                r = mid;
+            }
+        }
+
+        // Return the index where the target can be inserted
+        return l;
+    }
+
+    /**
+     * Calculates the length of the Longest Increasing Subsequence (LIS) in the given array.
+     *
+     * @param arr The input array of integers.
+     * @return The length of the LIS.
+     */
+    public static int lengthOfLIS(int[] arr) {
+        if (arr == null || arr.length == 0) {
+            return 0; // Return 0 for empty or null arrays
+        }
+
+        // tails[i] - the smallest end element of an increasing subsequence of length i+1
+        int[] tails = new int[arr.length];
+        // size - the length of the longest increasing subsequence found so far
+        int size = 0;
+
+        for (int x : arr) {
+            // Find the position to replace or extend the subsequence
+            int index = lowerBound(tails, x, size);
+
+            // Update the tails array with the current element
+            tails[index] = x;
+
+            // If the element extends the subsequence, increase the size
+            if (index == size) {
+                size++;
+            }
+        }
+
+        // Return the length of the LIS
+        return size;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogNTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogNTest.java
new file mode 100644
index 000000000000..dc87d6751460
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogNTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class LongestIncreasingSubsequenceNLogNTest {
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new int[] {10, 9, 2, 5, 3, 7, 101, 18}, 4), Arguments.of(new int[] {0, 1, 0, 3, 2, 3}, 4), Arguments.of(new int[] {7, 7, 7, 7, 7}, 1), Arguments.of(new int[] {1, 3, 5, 4, 7}, 4), Arguments.of(new int[] {}, 0), Arguments.of(new int[] {10}, 1),
+            Arguments.of(new int[] {3, 10, 2, 1, 20}, 3), Arguments.of(new int[] {50, 3, 10, 7, 40, 80}, 4));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testLengthOfLIS(int[] input, int expected) {
+        assertEquals(expected, LongestIncreasingSubsequenceNLogN.lengthOfLIS(input));
+    }
+}

From f91cae7e03bdcdf2bdbb665bfdf7b60b6060c0e2 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 22 Apr 2025 00:28:23 +0300
Subject: [PATCH 0789/1338] Bump com.h3xstream.findsecbugs:findsecbugs-plugin
 from 1.13.0 to 1.14.0 (#6225)

Bumps [com.h3xstream.findsecbugs:findsecbugs-plugin](https://github.com/find-sec-bugs/find-sec-bugs) from 1.13.0 to 1.14.0.
- [Release notes](https://github.com/find-sec-bugs/find-sec-bugs/releases)
- [Changelog](https://github.com/find-sec-bugs/find-sec-bugs/blob/master/CHANGELOG.md)
- [Commits](https://github.com/find-sec-bugs/find-sec-bugs/commits)

---
updated-dependencies:
- dependency-name: com.h3xstream.findsecbugs:findsecbugs-plugin
  dependency-version: 1.14.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 62851d2f55d2..2459d8e0c9df 100644
--- a/pom.xml
+++ b/pom.xml
@@ -135,7 +135,7 @@
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>
                             <artifactId>findsecbugs-plugin</artifactId>
-                            <version>1.13.0</version>
+                            <version>1.14.0</version>
                         </plugin>
                     </plugins>
                 </configuration>

From 7a16daf9a74a8c24d29033d8485fa005fe751dd2 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 23 Apr 2025 00:52:16 +0300
Subject: [PATCH 0790/1338] Bump org.apache.commons:commons-collections4 from
 4.5.0-M3 to 4.5.0 (#6226)

Bumps org.apache.commons:commons-collections4 from 4.5.0-M3 to 4.5.0.

---
updated-dependencies:
- dependency-name: org.apache.commons:commons-collections4
  dependency-version: 4.5.0
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 2459d8e0c9df..403c3d31728f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -53,7 +53,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-collections4</artifactId>
-            <version>4.5.0-M3</version>
+            <version>4.5.0</version>
         </dependency>
     </dependencies>
 

From d866fbd32ad35a9e73444aa717cfcbf93a493437 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 29 Apr 2025 10:27:51 +0300
Subject: [PATCH 0791/1338] Bump com.puppycrawl.tools:checkstyle from 10.23.0
 to 10.23.1 (#6228)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.23.0 to 10.23.1.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.23.0...checkstyle-10.23.1)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 10.23.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 403c3d31728f..04128a7a3430 100644
--- a/pom.xml
+++ b/pom.xml
@@ -115,7 +115,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.23.0</version>
+                    <version>10.23.1</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 571d05caa8b851461d490cdfbba9124ee7af598a Mon Sep 17 00:00:00 2001
From: Muhammad Ezzat <muhammadaymanezzat@gmail.com>
Date: Mon, 5 May 2025 18:09:28 +0300
Subject: [PATCH 0792/1338] Add Karger's minimum cut algorithm (#6233)

---
 .../randomized/KargerMinCut.java              | 195 ++++++++++++++++++
 .../randomized/KargerMinCutTest.java          | 114 ++++++++++
 2 files changed, 309 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/randomized/KargerMinCut.java
 create mode 100644 src/test/java/com/thealgorithms/randomized/KargerMinCutTest.java

diff --git a/src/main/java/com/thealgorithms/randomized/KargerMinCut.java b/src/main/java/com/thealgorithms/randomized/KargerMinCut.java
new file mode 100644
index 000000000000..14f1f97450a0
--- /dev/null
+++ b/src/main/java/com/thealgorithms/randomized/KargerMinCut.java
@@ -0,0 +1,195 @@
+package com.thealgorithms.randomized;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Random;
+import java.util.Set;
+
+/**
+ * Implementation of Karger's Minimum Cut algorithm.
+ *
+ * <p>Karger's algorithm is a randomized algorithm to compute the minimum cut of a connected graph.
+ * A minimum cut is the smallest set of edges that, if removed, would split the graph into two
+ * disconnected components.
+ *
+ * <p>The algorithm works by repeatedly contracting random edges in the graph until only two
+ * nodes remain. The edges between these two nodes represent a cut. By running the algorithm
+ * multiple times and keeping track of the smallest cut found, the probability of finding the
+ * true minimum cut increases.
+ *
+ * <p>Key steps of the algorithm:
+ * <ol>
+ *   <li>Randomly select an edge and contract it, merging the two nodes into one.</li>
+ *   <li>Repeat the contraction process until only two nodes remain.</li>
+ *   <li>Count the edges between the two remaining nodes to determine the cut size.</li>
+ *   <li>Repeat the process multiple times to improve the likelihood of finding the true minimum cut.</li>
+ * </ol>
+ * <p>
+ * See more: <a href="https://en.wikipedia.org/wiki/Karger%27s_algorithm">Karger's algorithm</a>
+ *
+ * @author MuhammadEzzatHBK
+ */
+public final class KargerMinCut {
+
+    /**
+     * Output of the Karger algorithm.
+     *
+     * @param first  The first set of nodes in the cut.
+     * @param second The second set of nodes in the cut.
+     * @param minCut The size of the minimum cut.
+     */
+    public record KargerOutput(Set<Integer> first, Set<Integer> second, int minCut) {
+    }
+
+    private KargerMinCut() {
+    }
+
+    public static KargerOutput findMinCut(Collection<Integer> nodeSet, List<int[]> edges) {
+        return findMinCut(nodeSet, edges, 100);
+    }
+
+    /**
+     * Finds the minimum cut of a graph using Karger's algorithm.
+     *
+     * @param nodeSet:    Input graph nodes
+     * @param edges:      Input graph edges
+     * @param iterations: Iterations to run the algorithms for, more iterations = more accuracy
+     * @return A KargerOutput object containing the two sets of nodes and the size of the minimum cut.
+     */
+    public static KargerOutput findMinCut(Collection<Integer> nodeSet, List<int[]> edges, int iterations) {
+        Graph graph = new Graph(nodeSet, edges);
+        KargerOutput minCut = new KargerOutput(new HashSet<>(), new HashSet<>(), Integer.MAX_VALUE);
+        KargerOutput output;
+
+        // Run the algorithm multiple times to increase the probability of finding
+        for (int i = 0; i < iterations; i++) {
+            Graph clone = graph.copy();
+            output = clone.findMinCut();
+            if (output.minCut < minCut.minCut) {
+                minCut = output;
+            }
+        }
+        return minCut;
+    }
+
+    private static class DisjointSetUnion {
+        private final int[] parent;
+        int setCount;
+
+        DisjointSetUnion(int size) {
+            parent = new int[size];
+            for (int i = 0; i < size; i++) {
+                parent[i] = i;
+            }
+            setCount = size;
+        }
+
+        int find(int i) {
+            // If it's not its own parent, then it's not the root of its set
+            if (parent[i] != i) {
+                // Recursively find the root of its parent
+                // and update i's parent to point directly to the root (path compression)
+                parent[i] = find(parent[i]);
+            }
+
+            // Return the root (representative) of the set
+            return parent[i];
+        }
+
+        void union(int u, int v) {
+            // Find the root of each node
+            int rootU = find(u);
+            int rootV = find(v);
+
+            // If they belong to different sets, merge them
+            if (rootU != rootV) {
+                // Make rootV point to rootU — merge the two sets
+                parent[rootV] = rootU;
+
+                // Reduce the count of disjoint sets by 1
+                setCount--;
+            }
+        }
+
+        boolean inSameSet(int u, int v) {
+            return find(u) == find(v);
+        }
+
+        /*
+          This is a verbosity method, it's not a part of the core algorithm,
+          But it helps us provide more useful output.
+        */
+        Set<Integer> getAnySet() {
+            int aRoot = find(0); // Get one of the two roots
+
+            Set<Integer> set = new HashSet<>();
+            for (int i = 0; i < parent.length; i++) {
+                if (find(i) == aRoot) {
+                    set.add(i);
+                }
+            }
+
+            return set;
+        }
+    }
+
+    private static class Graph {
+        private final List<Integer> nodes;
+        private final List<int[]> edges;
+
+        Graph(Collection<Integer> nodeSet, List<int[]> edges) {
+            this.nodes = new ArrayList<>(nodeSet);
+            this.edges = new ArrayList<>();
+            for (int[] e : edges) {
+                this.edges.add(new int[] {e[0], e[1]});
+            }
+        }
+
+        Graph copy() {
+            return new Graph(this.nodes, this.edges);
+        }
+
+        KargerOutput findMinCut() {
+            DisjointSetUnion dsu = new DisjointSetUnion(nodes.size());
+            List<int[]> workingEdges = new ArrayList<>(edges);
+
+            Random rand = new Random();
+
+            while (dsu.setCount > 2) {
+                int[] e = workingEdges.get(rand.nextInt(workingEdges.size()));
+                if (!dsu.inSameSet(e[0], e[1])) {
+                    dsu.union(e[0], e[1]);
+                }
+            }
+
+            int cutEdges = 0;
+            for (int[] e : edges) {
+                if (!dsu.inSameSet(e[0], e[1])) {
+                    cutEdges++;
+                }
+            }
+
+            return collectResult(dsu, cutEdges);
+        }
+
+        /*
+            This is a verbosity method, it's not a part of the core algorithm,
+            But it helps us provide more useful output.
+        */
+        private KargerOutput collectResult(DisjointSetUnion dsu, int cutEdges) {
+            Set<Integer> firstIndices = dsu.getAnySet();
+            Set<Integer> firstSet = new HashSet<>();
+            Set<Integer> secondSet = new HashSet<>();
+            for (int i = 0; i < nodes.size(); i++) {
+                if (firstIndices.contains(i)) {
+                    firstSet.add(nodes.get(i));
+                } else {
+                    secondSet.add(nodes.get(i));
+                }
+            }
+            return new KargerOutput(firstSet, secondSet, cutEdges);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/randomized/KargerMinCutTest.java b/src/test/java/com/thealgorithms/randomized/KargerMinCutTest.java
new file mode 100644
index 000000000000..876b6bf45eaf
--- /dev/null
+++ b/src/test/java/com/thealgorithms/randomized/KargerMinCutTest.java
@@ -0,0 +1,114 @@
+package com.thealgorithms.randomized;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class KargerMinCutTest {
+
+    @Test
+    public void testSimpleGraph() {
+        // Graph: 0 -- 1
+        Collection<Integer> nodes = Arrays.asList(0, 1);
+        List<int[]> edges = List.of(new int[] {0, 1});
+
+        KargerMinCut.KargerOutput result = KargerMinCut.findMinCut(nodes, edges);
+
+        assertEquals(1, result.minCut());
+        assertTrue(result.first().contains(0) || result.first().contains(1));
+        assertTrue(result.second().contains(0) || result.second().contains(1));
+    }
+
+    @Test
+    public void testTriangleGraph() {
+        // Graph: 0 -- 1 -- 2 -- 0
+        Collection<Integer> nodes = Arrays.asList(0, 1, 2);
+        List<int[]> edges = List.of(new int[] {0, 1}, new int[] {1, 2}, new int[] {2, 0});
+
+        KargerMinCut.KargerOutput result = KargerMinCut.findMinCut(nodes, edges);
+
+        assertEquals(2, result.minCut());
+    }
+
+    @Test
+    public void testSquareGraph() {
+        // Graph: 0 -- 1
+        //        |    |
+        //        3 -- 2
+        Collection<Integer> nodes = Arrays.asList(0, 1, 2, 3);
+        List<int[]> edges = List.of(new int[] {0, 1}, new int[] {1, 2}, new int[] {2, 3}, new int[] {3, 0});
+
+        KargerMinCut.KargerOutput result = KargerMinCut.findMinCut(nodes, edges);
+
+        assertEquals(2, result.minCut());
+    }
+
+    @Test
+    public void testDisconnectedGraph() {
+        // Graph: 0 -- 1   2 -- 3
+        Collection<Integer> nodes = Arrays.asList(0, 1, 2, 3);
+        List<int[]> edges = List.of(new int[] {0, 1}, new int[] {2, 3});
+
+        KargerMinCut.KargerOutput result = KargerMinCut.findMinCut(nodes, edges);
+
+        assertEquals(0, result.minCut());
+    }
+
+    @Test
+    public void testCompleteGraph() {
+        // Complete Graph: 0 -- 1 -- 2 -- 3 (all nodes connected to each other)
+        Collection<Integer> nodes = Arrays.asList(0, 1, 2, 3);
+        List<int[]> edges = List.of(new int[] {0, 1}, new int[] {0, 2}, new int[] {0, 3}, new int[] {1, 2}, new int[] {1, 3}, new int[] {2, 3});
+
+        KargerMinCut.KargerOutput result = KargerMinCut.findMinCut(nodes, edges);
+
+        assertEquals(3, result.minCut());
+    }
+
+    @Test
+    public void testSingleNodeGraph() {
+        // Graph: Single node with no edges
+        Collection<Integer> nodes = List.of(0);
+        List<int[]> edges = List.of();
+
+        KargerMinCut.KargerOutput result = KargerMinCut.findMinCut(nodes, edges);
+
+        assertEquals(0, result.minCut());
+        assertTrue(result.first().contains(0));
+        assertTrue(result.second().isEmpty());
+    }
+
+    @Test
+    public void testTwoNodesNoEdge() {
+        // Graph: 0   1 (no edges)
+        Collection<Integer> nodes = Arrays.asList(0, 1);
+        List<int[]> edges = List.of();
+
+        KargerMinCut.KargerOutput result = KargerMinCut.findMinCut(nodes, edges);
+
+        assertEquals(0, result.minCut());
+        assertTrue(result.first().contains(0) || result.first().contains(1));
+        assertTrue(result.second().contains(0) || result.second().contains(1));
+    }
+
+    @Test
+    public void testComplexGraph() {
+        // Nodes: 0, 1, 2, 3, 4, 5, 6, 7, 8
+        // Edges: Fully connected graph with additional edges for complexity
+        Collection<Integer> nodes = Arrays.asList(0, 1, 2, 3, 4, 5, 6, 7, 8);
+        List<int[]> edges = List.of(new int[] {0, 1}, new int[] {0, 2}, new int[] {0, 3}, new int[] {0, 4}, new int[] {0, 5}, new int[] {1, 2}, new int[] {1, 3}, new int[] {1, 4}, new int[] {1, 5}, new int[] {1, 6}, new int[] {2, 3}, new int[] {2, 4}, new int[] {2, 5}, new int[] {2, 6},
+            new int[] {2, 7}, new int[] {3, 4}, new int[] {3, 5}, new int[] {3, 6}, new int[] {3, 7}, new int[] {3, 8}, new int[] {4, 5}, new int[] {4, 6}, new int[] {4, 7}, new int[] {4, 8}, new int[] {5, 6}, new int[] {5, 7}, new int[] {5, 8}, new int[] {6, 7}, new int[] {6, 8}, new int[] {7, 8},
+            new int[] {0, 6}, new int[] {1, 7}, new int[] {2, 8});
+
+        KargerMinCut.KargerOutput result = KargerMinCut.findMinCut(nodes, edges);
+
+        // The exact minimum cut value depends on the randomization, but it should be consistent
+        // for this graph structure. For a fully connected graph, the minimum cut is typically
+        // determined by the smallest number of edges connecting two partitions.
+        assertTrue(result.minCut() > 0);
+    }
+}

From c02074e191102fe169a70cd7c585e87a2a048511 Mon Sep 17 00:00:00 2001
From: Andrii Siriak <siryaka@gmail.com>
Date: Fri, 9 May 2025 23:10:36 +0300
Subject: [PATCH 0793/1338] Update CODEOWNERS

---
 .github/CODEOWNERS | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 0a19890aed44..8a0b18a54c0b 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1 +1 @@
-* @yanglbme @vil02 @BamaCharanChhandogi @alxkm @siriak
+* @DenizAltunkapan @yanglbme @vil02 @BamaCharanChhandogi @alxkm @siriak

From 6fe630cdf2be76fdac75418890e129e67da8cf2b Mon Sep 17 00:00:00 2001
From: Muhammad Ezzat <muhammadaymanezzat@gmail.com>
Date: Fri, 9 May 2025 23:27:27 +0300
Subject: [PATCH 0794/1338] Add Monte Carlo's Integral Approximation (#6235)

---
 .../randomized/MonteCarloIntegration.java     | 82 +++++++++++++++++
 .../randomized/MonteCarloIntegrationTest.java | 91 +++++++++++++++++++
 2 files changed, 173 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java
 create mode 100644 src/test/java/com/thealgorithms/randomized/MonteCarloIntegrationTest.java

diff --git a/src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java b/src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java
new file mode 100644
index 000000000000..05d7abbbcd6c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java
@@ -0,0 +1,82 @@
+package com.thealgorithms.randomized;
+
+import java.util.Random;
+import java.util.function.Function;
+
+/**
+ * A demonstration of the Monte Carlo integration algorithm in Java.
+ *
+ * <p>This class estimates the value of definite integrals using randomized sampling,
+ * also known as the Monte Carlo method. It is particularly effective for:
+ * <ul>
+ *   <li>Functions that are difficult or impossible to integrate analytically</li>
+ *   <li>High-dimensional integrals where traditional methods are inefficient</li>
+ *   <li>Simulation and probabilistic analysis tasks</li>
+ * </ul>
+ *
+ * <p>The core idea is to sample random points uniformly from the integration domain,
+ * evaluate the function at those points, and compute the scaled average to estimate the integral.
+ *
+ * <p>For a one-dimensional integral over [a, b], the approximation is the function range (b-a),
+ * multiplied by the function average result for a random sample.
+ * See more: <a href="https://en.wikipedia.org/wiki/Monte_Carlo_integration">Monte Carlo Integration</a>
+ *
+ * @author: MuhammadEzzatHBK
+ */
+
+public final class MonteCarloIntegration {
+
+    private MonteCarloIntegration() {
+    }
+
+    /**
+     * Approximates the definite integral of a given function over a specified
+     * interval using the Monte Carlo method with a fixed random seed for
+     * reproducibility.
+     *
+     * @param fx    the function to integrate
+     * @param a     the lower bound of the interval
+     * @param b     the upper bound of the interval
+     * @param n     the number of random samples to use
+     * @param seed  the seed for the random number generator
+     * @return      the approximate value of the integral
+     */
+    public static double approximate(Function<Double, Double> fx, double a, double b, int n, long seed) {
+        return doApproximate(fx, a, b, n, new Random(seed));
+    }
+
+    /**
+     * Approximates the definite integral of a given function over a specified
+     * interval using the Monte Carlo method with a random seed based on the
+     * current system time for more randomness.
+     *
+     * @param fx    the function to integrate
+     * @param a     the lower bound of the interval
+     * @param b     the upper bound of the interval
+     * @param n     the number of random samples to use
+     * @return      the approximate value of the integral
+     */
+    public static double approximate(Function<Double, Double> fx, double a, double b, int n) {
+        return doApproximate(fx, a, b, n, new Random(System.currentTimeMillis()));
+    }
+
+    private static double doApproximate(Function<Double, Double> fx, double a, double b, int n, Random generator) {
+        if (!validate(fx, a, b, n)) {
+            throw new IllegalArgumentException("Invalid input parameters");
+        }
+        double totalArea = 0.0;
+        double interval = b - a;
+        for (int i = 0; i < n; i++) {
+            double x = a + generator.nextDouble() * interval;
+            totalArea += fx.apply(x);
+        }
+        return interval * totalArea / n;
+    }
+
+    private static boolean validate(Function<Double, Double> fx, double a, double b, int n) {
+        boolean isFunctionValid = fx != null;
+        boolean isIntervalValid = a < b;
+        boolean isSampleSizeValid = n > 0;
+        return isFunctionValid && isIntervalValid && isSampleSizeValid;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/randomized/MonteCarloIntegrationTest.java b/src/test/java/com/thealgorithms/randomized/MonteCarloIntegrationTest.java
new file mode 100644
index 000000000000..2a3a84b5ceea
--- /dev/null
+++ b/src/test/java/com/thealgorithms/randomized/MonteCarloIntegrationTest.java
@@ -0,0 +1,91 @@
+package com.thealgorithms.randomized;
+
+import static com.thealgorithms.randomized.MonteCarloIntegration.approximate;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.function.Function;
+import org.junit.jupiter.api.Test;
+
+class MonteCarloIntegrationTest {
+
+    private static final double EPSILON = 0.03; // Allow 3% error margin
+
+    @Test
+    void testConstantFunction() {
+        // Integral of f(x) = 2 from 0 to 1 is 2
+        Function<Double, Double> constant = x -> 2.0;
+        double result = approximate(constant, 0, 1, 10000);
+        assertEquals(2.0, result, EPSILON);
+    }
+
+    @Test
+    void testLinearFunction() {
+        // Integral of f(x) = x from 0 to 1 is 0.5
+        Function<Double, Double> linear = Function.identity();
+        double result = approximate(linear, 0, 1, 10000);
+        assertEquals(0.5, result, EPSILON);
+    }
+
+    @Test
+    void testQuadraticFunction() {
+        // Integral of f(x) = x^2 from 0 to 1 is 1/3
+        Function<Double, Double> quadratic = x -> x * x;
+        double result = approximate(quadratic, 0, 1, 10000);
+        assertEquals(1.0 / 3.0, result, EPSILON);
+    }
+
+    @Test
+    void testLargeSampleSize() {
+        // Integral of f(x) = x^2 from 0 to 1 is 1/3
+        Function<Double, Double> quadratic = x -> x * x;
+        double result = approximate(quadratic, 0, 1, 50000000);
+        assertEquals(1.0 / 3.0, result, EPSILON / 2); // Larger sample size, smaller error margin
+    }
+
+    @Test
+    void testReproducibility() {
+        Function<Double, Double> linear = Function.identity();
+        double result1 = approximate(linear, 0, 1, 10000, 42L);
+        double result2 = approximate(linear, 0, 1, 10000, 42L);
+        assertEquals(result1, result2, 0.0); // Exactly equal
+    }
+
+    @Test
+    void testNegativeInterval() {
+        // Integral of f(x) = x from -1 to 1 is 0
+        Function<Double, Double> linear = Function.identity();
+        double result = approximate(linear, -1, 1, 10000);
+        assertEquals(0.0, result, EPSILON);
+    }
+
+    @Test
+    void testNullFunction() {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> approximate(null, 0, 1, 1000));
+        assertNotNull(exception);
+    }
+
+    @Test
+    void testInvalidInterval() {
+        Function<Double, Double> linear = Function.identity();
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> {
+            approximate(linear, 2, 1, 1000); // b <= a
+        });
+        assertNotNull(exception);
+    }
+
+    @Test
+    void testZeroSampleSize() {
+        Function<Double, Double> linear = Function.identity();
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> approximate(linear, 0, 1, 0));
+        assertNotNull(exception);
+    }
+
+    @Test
+    void testNegativeSampleSize() {
+        Function<Double, Double> linear = Function.identity();
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> approximate(linear, 0, 1, -100));
+        assertNotNull(exception);
+    }
+}

From b09766ede4474ca4e1148d46ce2d2705cb2c3ef0 Mon Sep 17 00:00:00 2001
From: Vibhu Khera <vibhukhera3@gmail.com>
Date: Sat, 10 May 2025 03:20:09 +0530
Subject: [PATCH 0795/1338] Add Randomized Quick Sort (#6234)

---
 .../randomized/RandomizedQuickSort.java       | 68 +++++++++++++++++++
 .../randomized/RandomizedQuickSortTest.java   | 44 ++++++++++++
 2 files changed, 112 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/randomized/RandomizedQuickSort.java
 create mode 100644 src/test/java/com/thealgorithms/randomized/RandomizedQuickSortTest.java

diff --git a/src/main/java/com/thealgorithms/randomized/RandomizedQuickSort.java b/src/main/java/com/thealgorithms/randomized/RandomizedQuickSort.java
new file mode 100644
index 000000000000..e9af223a0622
--- /dev/null
+++ b/src/main/java/com/thealgorithms/randomized/RandomizedQuickSort.java
@@ -0,0 +1,68 @@
+package com.thealgorithms.randomized;
+
+/**
+ * This class implements the Randomized QuickSort algorithm.
+ * It selects a pivot randomly to improve performance on sorted or nearly sorted data.
+ * @author Vibhu Khera
+ */
+public final class RandomizedQuickSort {
+
+    private RandomizedQuickSort() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    /**
+     * Sorts the array using the randomized quicksort algorithm.
+     *
+     * @param arr the array to sort
+     * @param low the starting index of the array
+     * @param high the ending index of the array
+     */
+    public static void randomizedQuickSort(int[] arr, int low, int high) {
+        if (low < high) {
+            int pivotIndex = partition(arr, low, high);
+            randomizedQuickSort(arr, low, pivotIndex - 1);
+            randomizedQuickSort(arr, pivotIndex + 1, high);
+        }
+    }
+
+    /**
+     * Partitions the array around a pivot chosen randomly.
+     *
+     * @param arr the array to partition
+     * @param low the starting index
+     * @param high the ending index
+     * @return the index of the pivot after partitioning
+     */
+    private static int partition(int[] arr, int low, int high) {
+        int pivotIndex = low + (int) (Math.random() * (high - low + 1));
+        int pivotValue = arr[pivotIndex];
+        swap(arr, pivotIndex, high); // Move pivot to end
+        int storeIndex = low;
+        for (int i = low; i < high; i++) {
+            if (arr[i] < pivotValue) {
+                swap(arr, storeIndex, i);
+                storeIndex++;
+            }
+        }
+        swap(arr, storeIndex, high); // Move pivot to its final place
+        return storeIndex;
+    }
+
+    /**
+     * Swaps two elements in the array, only if the indices are different.
+     *
+     * @param arr the array in which elements are to be swapped
+     * @param i the first index
+     * @param j the second index
+     */
+    private static void swap(int[] arr, int i, int j) {
+        // Skip if indices are the same
+        if (i == j) {
+            return;
+        }
+        int temp = arr[i];
+        arr[i] = arr[j];
+        arr[j] = temp;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/randomized/RandomizedQuickSortTest.java b/src/test/java/com/thealgorithms/randomized/RandomizedQuickSortTest.java
new file mode 100644
index 000000000000..ec3d5a0b3546
--- /dev/null
+++ b/src/test/java/com/thealgorithms/randomized/RandomizedQuickSortTest.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.randomized;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the RandomizedQuickSort class.
+ */
+public class RandomizedQuickSortTest {
+
+    /**
+     * Tests sorting of an array with multiple elements, including duplicates.
+     */
+    @Test
+    public void testRandomizedQuickSortMultipleElements() {
+        int[] arr = {3, 6, 8, 10, 1, 2, 1};
+        int[] expected = {1, 1, 2, 3, 6, 8, 10};
+        RandomizedQuickSort.randomizedQuickSort(arr, 0, arr.length - 1);
+        assertArrayEquals(expected, arr);
+    }
+
+    /**
+     * Tests sorting of an empty array.
+     */
+    @Test
+    public void testRandomizedQuickSortEmptyArray() {
+        int[] arr = {};
+        int[] expected = {};
+        RandomizedQuickSort.randomizedQuickSort(arr, 0, arr.length - 1);
+        assertArrayEquals(expected, arr);
+    }
+
+    /**
+     * Tests sorting of an array with a single element.
+     */
+    @Test
+    public void testRandomizedQuickSortSingleElement() {
+        int[] arr = {5};
+        int[] expected = {5};
+        RandomizedQuickSort.randomizedQuickSort(arr, 0, arr.length - 1);
+        assertArrayEquals(expected, arr);
+    }
+}

From 121bf1eaf8e1e0f4c5b83d12ecc9f40f0a4d6eea Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 21 May 2025 00:13:12 +0200
Subject: [PATCH 0796/1338] Bump org.mockito:mockito-core from 5.17.0 to 5.18.0
 (#6240)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.17.0 to 5.18.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.17.0...v5.18.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.18.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 04128a7a3430..2420f62fb97c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.17.0</version>
+            <version>5.18.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From d23a0ec5f4d08cd8646606dfba1902bc79554b83 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 23 May 2025 00:57:38 +0300
Subject: [PATCH 0797/1338] Bump com.puppycrawl.tools:checkstyle from 10.23.1
 to 10.24.0 (#6246)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.23.1 to 10.24.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.23.1...checkstyle-10.24.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 10.24.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 2420f62fb97c..415a0ae0cfd5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -115,7 +115,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.23.1</version>
+                    <version>10.24.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 2320b46b3f2eb1a0088188936500c8de9cf60bf0 Mon Sep 17 00:00:00 2001
From: Soham Kamble <121136639+skamble2@users.noreply.github.com>
Date: Wed, 28 May 2025 07:00:41 -0500
Subject: [PATCH 0798/1338] Add BTree implementation (#6248)

---
 .../datastructures/trees/BTree.java           | 323 ++++++++++++++++++
 .../datastructures/trees/BTreeTest.java       |  94 +++++
 2 files changed, 417 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/trees/BTree.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/BTreeTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/BTree.java b/src/main/java/com/thealgorithms/datastructures/trees/BTree.java
new file mode 100644
index 000000000000..2c19253b45e7
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/trees/BTree.java
@@ -0,0 +1,323 @@
+package com.thealgorithms.datastructures.trees;
+
+import java.util.ArrayList;
+
+/**
+ * Implementation of a B-Tree, a self-balancing tree data structure that maintains sorted data
+ * and allows searches, sequential access, insertions, and deletions in logarithmic time.
+ *
+ * B-Trees are generalizations of binary search trees in that a node can have more than two children.
+ * They're widely used in databases and file systems.
+ *
+ * For more information: https://en.wikipedia.org/wiki/B-tree
+ */
+
+public class BTree {
+    static class BTreeNode {
+        int[] keys;
+        int t; // Minimum degree (defines range for number of keys)
+        BTreeNode[] children;
+        int n; // Current number of keys
+        boolean leaf;
+
+        BTreeNode(int t, boolean leaf) {
+            this.t = t;
+            this.leaf = leaf;
+            this.keys = new int[2 * t - 1];
+            this.children = new BTreeNode[2 * t];
+            this.n = 0;
+        }
+
+        void traverse(ArrayList<Integer> result) {
+            for (int i = 0; i < n; i++) {
+                if (!leaf) {
+                    children[i].traverse(result);
+                }
+                result.add(keys[i]);
+            }
+            if (!leaf) {
+                children[n].traverse(result);
+            }
+        }
+
+        BTreeNode search(int key) {
+            int i = 0;
+            while (i < n && key > keys[i]) {
+                i++;
+            }
+            if (i < n && keys[i] == key) {
+                return this;
+            }
+            if (leaf) {
+                return null;
+            }
+            return children[i].search(key);
+        }
+
+        void insertNonFull(int key) {
+            int i = n - 1;
+            if (leaf) {
+                while (i >= 0 && keys[i] > key) {
+                    keys[i + 1] = keys[i];
+                    i--;
+                }
+                keys[i + 1] = key;
+                n++;
+            } else {
+                while (i >= 0 && keys[i] > key) {
+                    i--;
+                }
+                if (children[i + 1].n == 2 * t - 1) {
+                    splitChild(i + 1, children[i + 1]);
+                    if (keys[i + 1] < key) {
+                        i++;
+                    }
+                }
+                children[i + 1].insertNonFull(key);
+            }
+        }
+
+        void splitChild(int i, BTreeNode y) {
+            BTreeNode z = new BTreeNode(y.t, y.leaf);
+            z.n = t - 1;
+
+            System.arraycopy(y.keys, t, z.keys, 0, t - 1);
+            if (!y.leaf) {
+                System.arraycopy(y.children, t, z.children, 0, t);
+            }
+            y.n = t - 1;
+
+            for (int j = n; j >= i + 1; j--) {
+                children[j + 1] = children[j];
+            }
+            children[i + 1] = z;
+
+            for (int j = n - 1; j >= i; j--) {
+                keys[j + 1] = keys[j];
+            }
+            keys[i] = y.keys[t - 1];
+            n++;
+        }
+
+        void remove(int key) {
+            int idx = findKey(key);
+
+            if (idx < n && keys[idx] == key) {
+                if (leaf) {
+                    removeFromLeaf(idx);
+                } else {
+                    removeFromNonLeaf(idx);
+                }
+            } else {
+                if (leaf) {
+                    return; // Key not found
+                }
+
+                boolean flag = idx == n;
+                if (children[idx].n < t) {
+                    fill(idx);
+                }
+
+                if (flag && idx > n) {
+                    children[idx - 1].remove(key);
+                } else {
+                    children[idx].remove(key);
+                }
+            }
+        }
+
+        private int findKey(int key) {
+            int idx = 0;
+            while (idx < n && keys[idx] < key) {
+                ++idx;
+            }
+            return idx;
+        }
+
+        private void removeFromLeaf(int idx) {
+            for (int i = idx + 1; i < n; ++i) {
+                keys[i - 1] = keys[i];
+            }
+            n--;
+        }
+
+        private void removeFromNonLeaf(int idx) {
+            int key = keys[idx];
+            if (children[idx].n >= t) {
+                int pred = getPredecessor(idx);
+                keys[idx] = pred;
+                children[idx].remove(pred);
+            } else if (children[idx + 1].n >= t) {
+                int succ = getSuccessor(idx);
+                keys[idx] = succ;
+                children[idx + 1].remove(succ);
+            } else {
+                merge(idx);
+                children[idx].remove(key);
+            }
+        }
+
+        private int getPredecessor(int idx) {
+            BTreeNode cur = children[idx];
+            while (!cur.leaf) {
+                cur = cur.children[cur.n];
+            }
+            return cur.keys[cur.n - 1];
+        }
+
+        private int getSuccessor(int idx) {
+            BTreeNode cur = children[idx + 1];
+            while (!cur.leaf) {
+                cur = cur.children[0];
+            }
+            return cur.keys[0];
+        }
+
+        private void fill(int idx) {
+            if (idx != 0 && children[idx - 1].n >= t) {
+                borrowFromPrev(idx);
+            } else if (idx != n && children[idx + 1].n >= t) {
+                borrowFromNext(idx);
+            } else {
+                if (idx != n) {
+                    merge(idx);
+                } else {
+                    merge(idx - 1);
+                }
+            }
+        }
+
+        private void borrowFromPrev(int idx) {
+            BTreeNode child = children[idx];
+            BTreeNode sibling = children[idx - 1];
+
+            for (int i = child.n - 1; i >= 0; --i) {
+                child.keys[i + 1] = child.keys[i];
+            }
+
+            if (!child.leaf) {
+                for (int i = child.n; i >= 0; --i) {
+                    child.children[i + 1] = child.children[i];
+                }
+            }
+
+            child.keys[0] = keys[idx - 1];
+
+            if (!child.leaf) {
+                child.children[0] = sibling.children[sibling.n];
+            }
+
+            keys[idx - 1] = sibling.keys[sibling.n - 1];
+
+            child.n += 1;
+            sibling.n -= 1;
+        }
+
+        private void borrowFromNext(int idx) {
+            BTreeNode child = children[idx];
+            BTreeNode sibling = children[idx + 1];
+
+            child.keys[child.n] = keys[idx];
+
+            if (!child.leaf) {
+                child.children[child.n + 1] = sibling.children[0];
+            }
+
+            keys[idx] = sibling.keys[0];
+
+            for (int i = 1; i < sibling.n; ++i) {
+                sibling.keys[i - 1] = sibling.keys[i];
+            }
+
+            if (!sibling.leaf) {
+                for (int i = 1; i <= sibling.n; ++i) {
+                    sibling.children[i - 1] = sibling.children[i];
+                }
+            }
+
+            child.n += 1;
+            sibling.n -= 1;
+        }
+
+        private void merge(int idx) {
+            BTreeNode child = children[idx];
+            BTreeNode sibling = children[idx + 1];
+
+            child.keys[t - 1] = keys[idx];
+
+            for (int i = 0; i < sibling.n; ++i) {
+                child.keys[i + t] = sibling.keys[i];
+            }
+
+            if (!child.leaf) {
+                for (int i = 0; i <= sibling.n; ++i) {
+                    child.children[i + t] = sibling.children[i];
+                }
+            }
+
+            for (int i = idx + 1; i < n; ++i) {
+                keys[i - 1] = keys[i];
+            }
+
+            for (int i = idx + 2; i <= n; ++i) {
+                children[i - 1] = children[i];
+            }
+
+            child.n += sibling.n + 1;
+            n--;
+        }
+    }
+
+    private BTreeNode root;
+    private final int t;
+
+    public BTree(int t) {
+        this.root = null;
+        this.t = t;
+    }
+
+    public void traverse(ArrayList<Integer> result) {
+        if (root != null) {
+            root.traverse(result);
+        }
+    }
+
+    public boolean search(int key) {
+        return root != null && root.search(key) != null;
+    }
+
+    public void insert(int key) {
+        if (search(key)) {
+            return;
+        }
+        if (root == null) {
+            root = new BTreeNode(t, true);
+            root.keys[0] = key;
+            root.n = 1;
+        } else {
+            if (root.n == 2 * t - 1) {
+                BTreeNode s = new BTreeNode(t, false);
+                s.children[0] = root;
+                s.splitChild(0, root);
+                int i = 0;
+                if (s.keys[0] < key) {
+                    i++;
+                }
+                s.children[i].insertNonFull(key);
+                root = s;
+            } else {
+                root.insertNonFull(key);
+            }
+        }
+    }
+
+    public void delete(int key) {
+        if (root == null) {
+            return;
+        }
+        root.remove(key);
+        if (root.n == 0) {
+            root = root.leaf ? null : root.children[0];
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/BTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/BTreeTest.java
new file mode 100644
index 000000000000..da29e117f25d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/BTreeTest.java
@@ -0,0 +1,94 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import org.junit.jupiter.api.Test;
+
+public class BTreeTest {
+
+    @Test
+    public void testInsertSearchDelete() {
+        BTree bTree = new BTree(3); // Minimum degree t = 3
+
+        int[] values = {10, 20, 5, 6, 12, 30, 7, 17};
+        for (int val : values) {
+            bTree.insert(val);
+        }
+
+        for (int val : values) {
+            assertTrue(bTree.search(val), "Should find inserted value: " + val);
+        }
+
+        ArrayList<Integer> traversal = new ArrayList<>();
+        bTree.traverse(traversal);
+        assertEquals(Arrays.asList(5, 6, 7, 10, 12, 17, 20, 30), traversal);
+
+        bTree.delete(6);
+        assertFalse(bTree.search(6));
+        traversal.clear();
+        bTree.traverse(traversal);
+        assertEquals(Arrays.asList(5, 7, 10, 12, 17, 20, 30), traversal);
+    }
+
+    @Test
+    public void testEmptyTreeSearch() {
+        BTree bTree = new BTree(3);
+        assertFalse(bTree.search(42), "Search in empty tree should return false.");
+    }
+
+    @Test
+    public void testDuplicateInsertions() {
+        BTree bTree = new BTree(3);
+        bTree.insert(15);
+        bTree.insert(15); // Attempt duplicate
+        bTree.insert(15); // Another duplicate
+
+        ArrayList<Integer> traversal = new ArrayList<>();
+        bTree.traverse(traversal);
+
+        // Should contain only one 15
+        long count = traversal.stream().filter(x -> x == 15).count();
+        assertEquals(1, count, "Duplicate keys should not be inserted.");
+    }
+
+    @Test
+    public void testDeleteNonExistentKey() {
+        BTree bTree = new BTree(3);
+        bTree.insert(10);
+        bTree.insert(20);
+        bTree.delete(99); // Doesn't exist
+        assertTrue(bTree.search(10));
+        assertTrue(bTree.search(20));
+    }
+
+    @Test
+    public void testComplexInsertDelete() {
+        BTree bTree = new BTree(2); // Smaller degree to trigger splits more easily
+        int[] values = {1, 3, 7, 10, 11, 13, 14, 15, 18, 16, 19, 24, 25, 26, 21, 4, 5, 20, 22, 2, 17, 12, 6};
+
+        for (int val : values) {
+            bTree.insert(val);
+        }
+
+        for (int val : values) {
+            assertTrue(bTree.search(val));
+        }
+
+        int[] toDelete = {6, 13, 7, 4, 2, 16};
+        for (int val : toDelete) {
+            bTree.delete(val);
+            assertFalse(bTree.search(val));
+        }
+
+        ArrayList<Integer> remaining = new ArrayList<>();
+        bTree.traverse(remaining);
+
+        for (int val : toDelete) {
+            assertFalse(remaining.contains(val));
+        }
+    }
+}

From 8e6637b7cd7d49dbef62e0e9811f4ad91146635e Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Tue, 3 Jun 2025 17:25:13 +0200
Subject: [PATCH 0799/1338] fix: use last known working commit for infer to
 avoid build failure (#6257)

---
 .github/workflows/infer.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index a07c6f458083..ffadd13ff3bd 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -41,6 +41,7 @@ jobs:
           cd ..
           git clone https://github.com/facebook/infer.git
           cd infer
+          git checkout 01aaa268f9d38723ba69c139e10f9e2a04b40b1c
           ./build-infer.sh java
           cp -r infer ../Java
 

From 3b9bdcc066847adcc2a736ba70c6f84337f9b4d1 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 3 Jun 2025 17:43:15 +0200
Subject: [PATCH 0800/1338] style: do not use `ArgumentsProvider` as deprecated
 (#6253)

---
 .../com/thealgorithms/sorts/SpreadSortTest.java    | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/src/test/java/com/thealgorithms/sorts/SpreadSortTest.java b/src/test/java/com/thealgorithms/sorts/SpreadSortTest.java
index a4992a02abfa..896aee8ba4ab 100644
--- a/src/test/java/com/thealgorithms/sorts/SpreadSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SpreadSortTest.java
@@ -6,8 +6,7 @@
 import org.junit.jupiter.api.function.Executable;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
-import org.junit.jupiter.params.provider.ArgumentsProvider;
-import org.junit.jupiter.params.provider.ArgumentsSource;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class SpreadSortTest extends SortingAlgorithmTest {
 
@@ -20,16 +19,13 @@ SortAlgorithm getSortAlgorithm() {
         return new SpreadSort();
     }
 
-    static class ConstructorArgumentsProvider implements ArgumentsProvider {
-        @Override
-        public Stream<? extends Arguments> provideArguments(org.junit.jupiter.api.extension.ExtensionContext context) {
-            return Stream.of(Arguments.of(0, 16, 2, IllegalArgumentException.class), Arguments.of(16, 0, 2, IllegalArgumentException.class), Arguments.of(16, 16, 0, IllegalArgumentException.class), Arguments.of(1001, 16, 2, IllegalArgumentException.class),
-                Arguments.of(16, 1001, 2, IllegalArgumentException.class), Arguments.of(16, 16, 101, IllegalArgumentException.class));
-        }
+    private static Stream<Arguments> wrongConstructorInputs() {
+        return Stream.of(Arguments.of(0, 16, 2, IllegalArgumentException.class), Arguments.of(16, 0, 2, IllegalArgumentException.class), Arguments.of(16, 16, 0, IllegalArgumentException.class), Arguments.of(1001, 16, 2, IllegalArgumentException.class),
+            Arguments.of(16, 1001, 2, IllegalArgumentException.class), Arguments.of(16, 16, 101, IllegalArgumentException.class));
     }
 
     @ParameterizedTest
-    @ArgumentsSource(ConstructorArgumentsProvider.class)
+    @MethodSource("wrongConstructorInputs")
     void testConstructor(int insertionSortThreshold, int initialBucketCapacity, int minBuckets, Class<Exception> expectedException) {
         Executable executable = () -> new SpreadSort(insertionSortThreshold, initialBucketCapacity, minBuckets);
         assertThrows(expectedException, executable);

From 292b4e506e9fcd61b1e8cd753c2194343831e095 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 3 Jun 2025 17:47:50 +0200
Subject: [PATCH 0801/1338] style: resolve
 `IMC_IMMATURE_CLASS_COLLECTION_RETURN` (#6256)

---
 src/test/java/com/thealgorithms/sorts/FlashSortTest.java | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/test/java/com/thealgorithms/sorts/FlashSortTest.java b/src/test/java/com/thealgorithms/sorts/FlashSortTest.java
index 6b1a74403a59..5b27975d3bea 100644
--- a/src/test/java/com/thealgorithms/sorts/FlashSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/FlashSortTest.java
@@ -5,7 +5,6 @@
 
 import java.lang.reflect.Method;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.List;
 import org.junit.jupiter.api.DynamicTest;
 import org.junit.jupiter.api.Test;
@@ -47,7 +46,7 @@ public void testCustomConstructorInvalidRatio(double ratio) {
     }
 
     @TestFactory
-    public Collection<DynamicTest> dynamicTestsForSorting() {
+    public List<DynamicTest> dynamicTestsForSorting() {
         List<DynamicTest> dynamicTests = new ArrayList<>();
         double[] ratios = {0.1, 0.2, 0.5, 0.9};
 
@@ -60,7 +59,7 @@ public Collection<DynamicTest> dynamicTestsForSorting() {
         return dynamicTests;
     }
 
-    private Collection<DynamicTest> createDynamicTestsForRatio(double ratio) {
+    private List<DynamicTest> createDynamicTestsForRatio(double ratio) {
         List<DynamicTest> dynamicTests = new ArrayList<>();
         for (TestMethod testMethod : getTestMethodsFromSuperClass()) {
             dynamicTests.add(DynamicTest.dynamicTest("Ratio: " + ratio + " - Test: " + testMethod.name(), testMethod.executable()));

From 424c4fb0ebdac36cb9f110d865dfa2faf34b481f Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 3 Jun 2025 16:08:41 +0000
Subject: [PATCH 0802/1338] Bump org.junit:junit-bom from 5.12.2 to 5.13.0
 (#6252)

* Bump org.junit:junit-bom from 5.12.2 to 5.13.0

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.12.2 to 5.13.0.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.12.2...r5.13.0)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 5.13.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* Update directory

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: dependabot[bot] <dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 415a0ae0cfd5..dd32dfd59bfd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.12.2</version>
+                <version>5.13.0</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From d546212974251500e949693c9ad21921dec90e51 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 3 Jun 2025 16:16:47 +0000
Subject: [PATCH 0803/1338] Bump com.mebigfatguy.fb-contrib:fb-contrib from
 7.6.9 to 7.6.10 (#6254)

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.6.9 to 7.6.10.
- [Commits](https://github.com/mebigfatguy/fb-contrib/commits/v7.6.10)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.6.10
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index dd32dfd59bfd..c98ff04b185d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -130,7 +130,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.9</version>
+                            <version>7.6.10</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

From 30f39abfc4dd24e9b21ec6dbd54472957ddd0b02 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 3 Jun 2025 16:24:14 +0000
Subject: [PATCH 0804/1338] Bump com.puppycrawl.tools:checkstyle from 10.24.0
 to 10.25.0 (#6255)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.24.0 to 10.25.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.24.0...checkstyle-10.25.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 10.25.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index c98ff04b185d..b4ca8562ff9d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -115,7 +115,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.24.0</version>
+                    <version>10.25.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From b3c2c7a2319659d57898f35c5d5ede458c4a5925 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 3 Jun 2025 18:34:01 +0200
Subject: [PATCH 0805/1338] Bump gitpod/workspace-java-21 from
 2025-02-10-10-54-28 to 2025-05-14-07-50-25 (#6249)

Bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2025-02-10-10-54-28 to 2025-05-14-07-50-25.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-version: 2025-05-14-07-50-25
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index ea6d32a5a377..69fee306e1e4 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2025-02-10-10-54-28
+FROM gitpod/workspace-java-21:2025-05-14-07-50-25
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From e123ca12c7d2d36dd76d322b8e02099ad3fedb0b Mon Sep 17 00:00:00 2001
From: Raveendra Pujari <72726513+raveendra11@users.noreply.github.com>
Date: Tue, 3 Jun 2025 17:09:46 -0500
Subject: [PATCH 0806/1338] tests: properly test `Isomorphic` (#6259)

Fixes #6258

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
---
 .../thealgorithms/strings/IsomorphicTest.java | 36 ++++++++-----------
 1 file changed, 14 insertions(+), 22 deletions(-)

diff --git a/src/test/java/com/thealgorithms/strings/IsomorphicTest.java b/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
index 0dac47551868..4dd13fbc34ee 100644
--- a/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
+++ b/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
@@ -1,31 +1,23 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public final class IsomorphicTest {
-    private IsomorphicTest() {
-    }
-
-    @Test
-    public static void main(String[] args) {
-        String str1 = "abbbbaac";
-        String str2 = "kffffkkd";
-
-        String str3 = "xyxyxy";
-        String str4 = "bnbnbn";
 
-        String str5 = "ghjknnmm";
-        String str6 = "wertpopo";
-
-        String str7 = "aaammmnnn";
-        String str8 = "ggghhhbbj";
+    @ParameterizedTest
+    @MethodSource("inputs")
+    public void testCheckStrings(String str1, String str2, Boolean expected) {
+        assertEquals(expected, Isomorphic.checkStrings(str1, str2));
+        assertEquals(expected, Isomorphic.checkStrings(str2, str1));
+    }
 
-        assertTrue(Isomorphic.checkStrings(str1, str2));
-        assertTrue(Isomorphic.checkStrings(str3, str4));
-        assertFalse(Isomorphic.checkStrings(str5, str6));
-        assertFalse(Isomorphic.checkStrings(str7, str8));
+    private static Stream<Arguments> inputs() {
+        return Stream.of(Arguments.of("", "", Boolean.TRUE), Arguments.of("", "a", Boolean.FALSE), Arguments.of("aaa", "aa", Boolean.FALSE), Arguments.of("abbbbaac", "kffffkkd", Boolean.TRUE), Arguments.of("xyxyxy", "bnbnbn", Boolean.TRUE), Arguments.of("ghjknnmm", "wertpopo", Boolean.FALSE),
+            Arguments.of("aaammmnnn", "ggghhhbbj", Boolean.FALSE));
     }
 }

From 27a774020cc89e1351fa973a36ecf546a6d53bd3 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 4 Jun 2025 22:37:38 +0200
Subject: [PATCH 0807/1338] style: include `SLS_SUSPICIOUS_LOOP_SEARCH` (#6260)

---
 spotbugs-exclude.xml                                |  3 ---
 .../com/thealgorithms/ciphers/AffineCipher.java     | 13 +------------
 2 files changed, 1 insertion(+), 15 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 3b77ced1a13e..bcc053611de6 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -195,9 +195,6 @@
     <Match>
         <Bug pattern="DRE_DECLARED_RUNTIME_EXCEPTION" />
     </Match>
-    <Match>
-        <Bug pattern="SLS_SUSPICIOUS_LOOP_SEARCH" />
-    </Match>
     <Match>
         <Bug pattern="BAS_BLOATED_ASSIGNMENT_SCOPE" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/ciphers/AffineCipher.java b/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
index b82681372f2b..979f18532eaa 100644
--- a/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/AffineCipher.java
@@ -68,6 +68,7 @@ static String decryptCipher(String cipher) {
             // then i will be the multiplicative inverse of a
             if (flag == 1) {
                 aInv = i;
+                break;
             }
         }
         for (int i = 0; i < cipher.length(); i++) {
@@ -83,16 +84,4 @@ static String decryptCipher(String cipher) {
 
         return msg.toString();
     }
-
-    // Driver code
-    public static void main(String[] args) {
-        String msg = "AFFINE CIPHER";
-
-        // Calling encryption function
-        String cipherText = encryptMessage(msg.toCharArray());
-        System.out.println("Encrypted Message is : " + cipherText);
-
-        // Calling Decryption function
-        System.out.println("Decrypted Message is: " + decryptCipher(cipherText));
-    }
 }

From ec6f09c3738fc420b3ac68d315c65281d7fb1b01 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 5 Jun 2025 13:23:28 +0200
Subject: [PATCH 0808/1338] chore: suppress `rawtypes` in selected classes
 (#6261)

---
 pom.xml                                                          | 1 -
 .../thealgorithms/backtracking/AllPathsFromSourceToTarget.java   | 1 +
 .../thealgorithms/datastructures/bloomfilter/BloomFilter.java    | 1 +
 .../java/com/thealgorithms/datastructures/graphs/Kruskal.java    | 1 +
 .../com/thealgorithms/datastructures/graphs/WelshPowell.java     | 1 +
 .../datastructures/hashmap/hashing/GenericHashMapUsingArray.java | 1 +
 .../thealgorithms/datastructures/hashmap/hashing/HashMap.java    | 1 +
 .../datastructures/hashmap/hashing/LinearProbingHashMap.java     | 1 +
 .../com/thealgorithms/datastructures/lists/CircleLinkedList.java | 1 +
 .../com/thealgorithms/datastructures/lists/CursorLinkedList.java | 1 +
 .../java/com/thealgorithms/datastructures/lists/SkipList.java    | 1 +
 .../dynamicprogramming/LongestArithmeticSubsequence.java         | 1 +
 .../java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java  | 1 +
 src/main/java/com/thealgorithms/searches/FibonacciSearch.java    | 1 +
 src/main/java/com/thealgorithms/sorts/MergeSort.java             | 1 +
 src/main/java/com/thealgorithms/sorts/SortAlgorithm.java         | 1 +
 src/main/java/com/thealgorithms/sorts/SpreadSort.java            | 1 +
 src/main/java/com/thealgorithms/sorts/TimSort.java               | 1 +
 .../com/thealgorithms/datastructures/graphs/KruskalTest.java     | 1 +
 src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java    | 1 +
 20 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b4ca8562ff9d..577634a4ceaa 100644
--- a/pom.xml
+++ b/pom.xml
@@ -76,7 +76,6 @@
                     <compilerArgs>
                         <arg>-Xlint:all</arg>
                         <arg>-Xlint:-auxiliaryclass</arg>
-                        <arg>-Xlint:-rawtypes</arg>
                         <arg>-Xlint:-unchecked</arg>
                         <arg>-Werror</arg>
                     </compilerArgs>
diff --git a/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java b/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
index 6f93b704ffb2..223b70fed66f 100644
--- a/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
+++ b/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
@@ -9,6 +9,7 @@
  *
  * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
  */
+@SuppressWarnings("rawtypes")
 public class AllPathsFromSourceToTarget {
 
     // No. of vertices in graph
diff --git a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
index a2edd3db2d8e..d60b95110fc2 100644
--- a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
+++ b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
@@ -12,6 +12,7 @@
  *
  * @param <T> The type of elements to be stored in the Bloom filter.
  */
+@SuppressWarnings("rawtypes")
 public class BloomFilter<T> {
 
     private final int numberOfHashFunctions;
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java b/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
index 25c4548daa7a..edf466a9b2ec 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
@@ -19,6 +19,7 @@
  *
  * <p><strong>Time Complexity:</strong> O(E log V), where E is the number of edges and V is the number of vertices.</p>
  */
+@SuppressWarnings("rawtypes")
 public class Kruskal {
 
     /**
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java b/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
index 26ca97736fe9..ff7230a9f348 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
@@ -22,6 +22,7 @@
  * For more information, see <a href="https://en.wikipedia.org/wiki/Graph_coloring">Graph Coloring</a>.
  * </p>
  */
+@SuppressWarnings("rawtypes")
 public final class WelshPowell {
     private static final int BLANK_COLOR = -1; // Constant representing an uncolored state
 
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
index 3637e323f097..62e68329b47b 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
@@ -23,6 +23,7 @@
  * @param <K> the type of keys maintained by this hash map
  * @param <V> the type of mapped values
  */
+@SuppressWarnings("rawtypes")
 public class GenericHashMapUsingArray<K, V> {
 
     private int size; // Total number of key-value pairs
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
index aed39c941430..1b0792b8a738 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java
@@ -8,6 +8,7 @@
  * @param <K> the type of keys maintained by this map
  * @param <V> the type of mapped values
  */
+@SuppressWarnings("rawtypes")
 public class HashMap<K, V> {
     private final int hashSize;
     private final LinkedList<K, V>[] buckets;
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java
index 10d5dc7decae..761a5fe83d18 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java
@@ -34,6 +34,7 @@
  * @param <Key> the type of keys maintained by this map
  * @param <Value> the type of mapped values
  */
+@SuppressWarnings("rawtypes")
 public class LinearProbingHashMap<Key extends Comparable<Key>, Value> extends Map<Key, Value> {
     private int hsize; // size of the hash table
     private Key[] keys; // array to store keys
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
index 422e8953625f..72a12cd58401 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java
@@ -10,6 +10,7 @@
  *
  * @param <E> the type of elements held in this list
  */
+@SuppressWarnings("rawtypes")
 public class CircleLinkedList<E> {
 
     /**
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
index ff3d39115c3b..24caf9d70bfe 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
@@ -10,6 +10,7 @@
  *
  * @param <T> the type of elements in this list
  */
+@SuppressWarnings("rawtypes")
 public class CursorLinkedList<T> {
 
     /**
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java b/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
index 3309ab24917d..f297cb79494c 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
@@ -29,6 +29,7 @@
  * @param <E> type of elements
  * @see <a href="https://en.wikipedia.org/wiki/Skip_list">Wiki. Skip list</a>
  */
+@SuppressWarnings("rawtypes")
 public class SkipList<E extends Comparable<E>> {
 
     /**
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java
index b5ac62b4674b..2368332c410f 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java
@@ -2,6 +2,7 @@
 
 import java.util.HashMap;
 
+@SuppressWarnings("rawtypes")
 final class LongestArithmeticSubsequence {
     private LongestArithmeticSubsequence() {
     }
diff --git a/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java b/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
index 51dc099ba32e..c81476eaec32 100644
--- a/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
+++ b/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
@@ -10,6 +10,7 @@
  * See more:
  * https://www.geeksforgeeks.org/function-to-check-if-a-singly-linked-list-is-palindrome/
  */
+@SuppressWarnings("rawtypes")
 public final class PalindromeSinglyLinkedList {
     private PalindromeSinglyLinkedList() {
     }
diff --git a/src/main/java/com/thealgorithms/searches/FibonacciSearch.java b/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
index 2124938bc258..d6f53f8d944a 100644
--- a/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
+++ b/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
@@ -15,6 +15,7 @@
  * Note: This algorithm requires that the input array be sorted.
  * </p>
  */
+@SuppressWarnings("rawtypes")
 public class FibonacciSearch implements SearchAlgorithm {
 
     /**
diff --git a/src/main/java/com/thealgorithms/sorts/MergeSort.java b/src/main/java/com/thealgorithms/sorts/MergeSort.java
index 9949783ca21b..86a184f67b26 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSort.java
@@ -7,6 +7,7 @@
  *
  * @see SortAlgorithm
  */
+@SuppressWarnings("rawtypes")
 class MergeSort implements SortAlgorithm {
 
     private Comparable[] aux;
diff --git a/src/main/java/com/thealgorithms/sorts/SortAlgorithm.java b/src/main/java/com/thealgorithms/sorts/SortAlgorithm.java
index 7a3ded37bf3f..72b046d12861 100644
--- a/src/main/java/com/thealgorithms/sorts/SortAlgorithm.java
+++ b/src/main/java/com/thealgorithms/sorts/SortAlgorithm.java
@@ -8,6 +8,7 @@
  *
  * @author Podshivalov Nikita (https://github.com/nikitap492)
  */
+@SuppressWarnings("rawtypes")
 public interface SortAlgorithm {
     /**
      * Main method arrays sorting algorithms
diff --git a/src/main/java/com/thealgorithms/sorts/SpreadSort.java b/src/main/java/com/thealgorithms/sorts/SpreadSort.java
index f1fd24f4735d..1401f3d454a8 100644
--- a/src/main/java/com/thealgorithms/sorts/SpreadSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SpreadSort.java
@@ -6,6 +6,7 @@
  * It distributes elements into buckets and recursively sorts these buckets.
  * This implementation is generic and can sort any array of elements that extend Comparable.
  */
+@SuppressWarnings("rawtypes")
 public class SpreadSort implements SortAlgorithm {
     private static final int MAX_INSERTION_SORT_THRESHOLD = 1000;
     private static final int MAX_INITIAL_BUCKET_CAPACITY = 1000;
diff --git a/src/main/java/com/thealgorithms/sorts/TimSort.java b/src/main/java/com/thealgorithms/sorts/TimSort.java
index 2d5bca2ef6f3..c592a74d1c8f 100644
--- a/src/main/java/com/thealgorithms/sorts/TimSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TimSort.java
@@ -7,6 +7,7 @@
  * <p>
  * For more details @see <a href="https://en.wikipedia.org/wiki/Timsort">TimSort Algorithm</a>
  */
+@SuppressWarnings("rawtypes")
 class TimSort implements SortAlgorithm {
     private static final int SUB_ARRAY_SIZE = 32;
     private Comparable[] aux;
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java
index b18f161ef1a6..c30dd2df26c5 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java
@@ -10,6 +10,7 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+@SuppressWarnings("rawtypes")
 public class KruskalTest {
 
     private Kruskal kruskal;
diff --git a/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java b/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
index 799052b22d83..561309e22ac9 100644
--- a/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
+++ b/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
@@ -8,6 +8,7 @@
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
+@SuppressWarnings("rawtypes")
 public class NumberOfDigitsTest {
 
     @ParameterizedTest

From 7602f1ef4cc3adbb7bff92348abf338bd88d4d72 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 5 Jun 2025 18:13:46 +0200
Subject: [PATCH 0809/1338] chore: suppress `unchecked` in selected classes
 (#6262)

---
 pom.xml                                                         | 1 -
 .../thealgorithms/backtracking/AllPathsFromSourceToTarget.java  | 2 +-
 .../thealgorithms/datastructures/buffers/CircularBuffer.java    | 1 +
 .../java/com/thealgorithms/datastructures/graphs/Kruskal.java   | 2 +-
 .../com/thealgorithms/datastructures/graphs/WelshPowell.java    | 2 +-
 .../hashmap/hashing/GenericHashMapUsingArray.java               | 2 +-
 .../thealgorithms/datastructures/lists/CursorLinkedList.java    | 2 +-
 .../java/com/thealgorithms/datastructures/lists/SkipList.java   | 2 +-
 .../thealgorithms/datastructures/queues/QueueByTwoStacks.java   | 1 +
 .../dynamicprogramming/LongestArithmeticSubsequence.java        | 2 +-
 src/main/java/com/thealgorithms/others/CRCAlgorithm.java        | 1 +
 src/main/java/com/thealgorithms/searches/FibonacciSearch.java   | 2 +-
 src/main/java/com/thealgorithms/sorts/TimSort.java              | 2 +-
 .../com/thealgorithms/datastructures/graphs/KruskalTest.java    | 2 +-
 src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java   | 2 +-
 15 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/pom.xml b/pom.xml
index 577634a4ceaa..ae449cdfac31 100644
--- a/pom.xml
+++ b/pom.xml
@@ -76,7 +76,6 @@
                     <compilerArgs>
                         <arg>-Xlint:all</arg>
                         <arg>-Xlint:-auxiliaryclass</arg>
-                        <arg>-Xlint:-unchecked</arg>
                         <arg>-Werror</arg>
                     </compilerArgs>
                 </configuration>
diff --git a/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java b/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
index 223b70fed66f..c35a36d97a57 100644
--- a/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
+++ b/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
@@ -9,7 +9,7 @@
  *
  * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
  */
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 public class AllPathsFromSourceToTarget {
 
     // No. of vertices in graph
diff --git a/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java b/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
index b709e16fd1f6..3b89c2119ae0 100644
--- a/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
+++ b/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java
@@ -10,6 +10,7 @@
  *
  * @param <Item> The type of elements stored in the circular buffer.
  */
+@SuppressWarnings("unchecked")
 public class CircularBuffer<Item> {
     private final Item[] buffer;
     private final CircularPointer putPointer;
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java b/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
index edf466a9b2ec..331d7196b61c 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java
@@ -19,7 +19,7 @@
  *
  * <p><strong>Time Complexity:</strong> O(E log V), where E is the number of edges and V is the number of vertices.</p>
  */
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 public class Kruskal {
 
     /**
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java b/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
index ff7230a9f348..4bf21c7ed4c1 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java
@@ -22,7 +22,7 @@
  * For more information, see <a href="https://en.wikipedia.org/wiki/Graph_coloring">Graph Coloring</a>.
  * </p>
  */
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 public final class WelshPowell {
     private static final int BLANK_COLOR = -1; // Constant representing an uncolored state
 
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
index 62e68329b47b..36d2cc8df160 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java
@@ -23,7 +23,7 @@
  * @param <K> the type of keys maintained by this hash map
  * @param <V> the type of mapped values
  */
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 public class GenericHashMapUsingArray<K, V> {
 
     private int size; // Total number of key-value pairs
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
index 24caf9d70bfe..63bb29034df2 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java
@@ -10,7 +10,7 @@
  *
  * @param <T> the type of elements in this list
  */
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 public class CursorLinkedList<T> {
 
     /**
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java b/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
index f297cb79494c..0b4fcd91483c 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
@@ -29,7 +29,7 @@
  * @param <E> type of elements
  * @see <a href="https://en.wikipedia.org/wiki/Skip_list">Wiki. Skip list</a>
  */
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 public class SkipList<E extends Comparable<E>> {
 
     /**
diff --git a/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java b/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java
index 11e5e9b83892..981b3b32e0b2 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java
@@ -11,6 +11,7 @@
  *
  * @param <T> The type of elements held in this queue.
  */
+@SuppressWarnings("unchecked")
 public class QueueByTwoStacks<T> {
 
     private final Stack<T> enqueueStk;
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java
index 2368332c410f..ba1def551192 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java
@@ -2,7 +2,7 @@
 
 import java.util.HashMap;
 
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 final class LongestArithmeticSubsequence {
     private LongestArithmeticSubsequence() {
     }
diff --git a/src/main/java/com/thealgorithms/others/CRCAlgorithm.java b/src/main/java/com/thealgorithms/others/CRCAlgorithm.java
index 284a290a5af8..00ddc86be820 100644
--- a/src/main/java/com/thealgorithms/others/CRCAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/CRCAlgorithm.java
@@ -7,6 +7,7 @@
 /**
  * @author dimgrichr
  */
+@SuppressWarnings("unchecked")
 public class CRCAlgorithm {
 
     private int correctMess;
diff --git a/src/main/java/com/thealgorithms/searches/FibonacciSearch.java b/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
index d6f53f8d944a..78dac0f0a712 100644
--- a/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
+++ b/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
@@ -15,7 +15,7 @@
  * Note: This algorithm requires that the input array be sorted.
  * </p>
  */
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 public class FibonacciSearch implements SearchAlgorithm {
 
     /**
diff --git a/src/main/java/com/thealgorithms/sorts/TimSort.java b/src/main/java/com/thealgorithms/sorts/TimSort.java
index c592a74d1c8f..13cd7fed35c7 100644
--- a/src/main/java/com/thealgorithms/sorts/TimSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TimSort.java
@@ -7,7 +7,7 @@
  * <p>
  * For more details @see <a href="https://en.wikipedia.org/wiki/Timsort">TimSort Algorithm</a>
  */
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 class TimSort implements SortAlgorithm {
     private static final int SUB_ARRAY_SIZE = 32;
     private Comparable[] aux;
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java
index c30dd2df26c5..7291cd6c319c 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java
@@ -10,7 +10,7 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 public class KruskalTest {
 
     private Kruskal kruskal;
diff --git a/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java b/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
index 561309e22ac9..153ab3347f1e 100644
--- a/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
+++ b/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java
@@ -8,7 +8,7 @@
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
-@SuppressWarnings("rawtypes")
+@SuppressWarnings({"rawtypes", "unchecked"})
 public class NumberOfDigitsTest {
 
     @ParameterizedTest

From ed4a724e33903e63f5ddd8e531774b40e59bf46a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 10 Jun 2025 22:52:11 +0200
Subject: [PATCH 0810/1338] Bump org.junit:junit-bom from 5.13.0 to 5.13.1
 (#6278)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.13.0 to 5.13.1.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](https://github.com/junit-team/junit5/compare/r5.13.0...r5.13.1)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 5.13.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index ae449cdfac31..47506868a02b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.13.0</version>
+                <version>5.13.1</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From e41c2b9456f1bb25756095a58e8096994dbee10b Mon Sep 17 00:00:00 2001
From: Saipriya Patnaik <143923417+Saipatnaik-23@users.noreply.github.com>
Date: Wed, 11 Jun 2025 02:37:24 +0530
Subject: [PATCH 0811/1338] Add Unit Tests for Empty and Single-Node Graphs in
 TopologicalSort (#6263)

---
 .../thealgorithms/sorts/TopologicalSortTest.java  | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java b/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
index de115b458fe7..d5588b2b968e 100644
--- a/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
@@ -3,6 +3,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertIterableEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.sorts.TopologicalSort.Graph;
 import java.util.LinkedList;
@@ -59,4 +60,18 @@ public void failureTest() {
             + "Back edge: 6 -> 2";
         assertEquals(exception.getMessage(), expected);
     }
+    @Test
+    void testEmptyGraph() {
+        Graph graph = new Graph();
+        LinkedList<String> sorted = TopologicalSort.sort(graph);
+        assertTrue(sorted.isEmpty());
+    }
+    @Test
+    void testSingleNode() {
+        Graph graph = new Graph();
+        graph.addEdge("A", "");
+        LinkedList<String> sorted = TopologicalSort.sort(graph);
+        assertEquals(1, sorted.size());
+        assertEquals("A", sorted.getFirst());
+    }
 }

From 20f04929be3f1f8ffc884350463e053490462d17 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 11 Jun 2025 15:52:58 +0200
Subject: [PATCH 0812/1338] chore: configure PMD to detect `main` methods
 (#6289)

---
 pmd-custom_ruleset.xml | 28 ++++++++++++++
 pmd-exclude.properties | 86 ++++++++++++++++++++++++++++++++++--------
 pom.xml                |  4 ++
 3 files changed, 103 insertions(+), 15 deletions(-)
 create mode 100644 pmd-custom_ruleset.xml

diff --git a/pmd-custom_ruleset.xml b/pmd-custom_ruleset.xml
new file mode 100644
index 000000000000..19bb1c7968f0
--- /dev/null
+++ b/pmd-custom_ruleset.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0"?>
+<ruleset name="TheAlgorithms/Java ruleset"
+    xmlns="http://pmd.sf.net/ruleset/1.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://pmd.sf.net/ruleset/1.0.0 http://pmd.sf.net/ruleset_xml_schema.xsd"
+    xsi:noNamespaceSchemaLocation="http://pmd.sf.net/ruleset_xml_schema.xsd">
+  <description>
+  Custom PMD checks for TheAlgorithms/Java
+  </description>
+<rule name="UselessMainMethod"
+      language="java"
+      message="The main method is redundant in this context"
+      class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
+    <description>
+        Avoid using the main method.
+    </description>
+    <priority>3</priority>
+    <properties>
+        <property name="xpath">
+            <value>
+<![CDATA[
+//MethodDeclaration[@Name = "main"]
+]]>
+            </value>
+        </property>
+    </properties>
+</rule>
+</ruleset>
diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index 1848412c9d30..4c0ed625d884 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -1,64 +1,120 @@
+com.thealgorithms.ciphers.AES=UselessMainMethod
+com.thealgorithms.ciphers.AESEncryption=UselessMainMethod
 com.thealgorithms.ciphers.AffineCipher=UselessParentheses
 com.thealgorithms.ciphers.DES=UselessParentheses
+com.thealgorithms.ciphers.ProductCipher=UselessMainMethod
 com.thealgorithms.ciphers.RSA=UselessParentheses
-com.thealgorithms.conversions.AnyBaseToAnyBase=UselessParentheses
+com.thealgorithms.conversions.AnyBaseToAnyBase=UselessMainMethod,UselessParentheses
 com.thealgorithms.conversions.AnytoAny=UselessParentheses
+com.thealgorithms.conversions.RgbHsvConversion=UselessMainMethod
 com.thealgorithms.datastructures.crdt.Pair=UnusedPrivateField
 com.thealgorithms.datastructures.graphs.AStar=UselessParentheses
 com.thealgorithms.datastructures.graphs.AdjacencyMatrixGraph=CollapsibleIfStatements,UnnecessaryFullyQualifiedName,UselessParentheses
+com.thealgorithms.datastructures.graphs.BellmanFord=UselessMainMethod
 com.thealgorithms.datastructures.graphs.BipartiteGraphDFS=CollapsibleIfStatements
+com.thealgorithms.datastructures.graphs.ConnectedComponent=UselessMainMethod
+com.thealgorithms.datastructures.graphs.Cycles=UselessMainMethod
+com.thealgorithms.datastructures.graphs.Graphs=UselessMainMethod
+com.thealgorithms.datastructures.graphs.KahnsAlgorithm=UselessMainMethod
+com.thealgorithms.datastructures.graphs.MatrixGraphs=UselessMainMethod
 com.thealgorithms.datastructures.hashmap.hashing.HashMapCuckooHashing=UselessParentheses
+com.thealgorithms.datastructures.hashmap.hashing.MainCuckooHashing=UselessMainMethod
 com.thealgorithms.datastructures.heaps.FibonacciHeap=UselessParentheses
 com.thealgorithms.datastructures.heaps.HeapNode=UselessParentheses
 com.thealgorithms.datastructures.lists.DoublyLinkedList=UselessParentheses
+com.thealgorithms.datastructures.lists.Link=UselessMainMethod
+com.thealgorithms.datastructures.lists.RandomNode=UselessMainMethod
 com.thealgorithms.datastructures.lists.SearchSinglyLinkedListRecursion=UselessParentheses
-com.thealgorithms.datastructures.lists.SinglyLinkedList=UnusedLocalVariable
+com.thealgorithms.datastructures.lists.SinglyLinkedList=UnusedLocalVariable,UselessMainMethod
+com.thealgorithms.datastructures.queues.Deque=UselessMainMethod
 com.thealgorithms.datastructures.queues.PriorityQueue=UselessParentheses
+com.thealgorithms.datastructures.trees.BSTRecursiveGeneric=UselessMainMethod
 com.thealgorithms.datastructures.trees.CheckBinaryTreeIsValidBST=UselessParentheses
+com.thealgorithms.datastructures.trees.LCA=UselessMainMethod
+com.thealgorithms.datastructures.trees.NearestRightKey=UselessMainMethod
+com.thealgorithms.datastructures.trees.PrintTopViewofTree=UselessMainMethod
 com.thealgorithms.datastructures.trees.SegmentTree=UselessParentheses
 com.thealgorithms.devutils.nodes.LargeTreeNode=UselessParentheses
 com.thealgorithms.devutils.nodes.SimpleNode=UselessParentheses
 com.thealgorithms.devutils.nodes.SimpleTreeNode=UselessParentheses
 com.thealgorithms.devutils.nodes.TreeNode=UselessParentheses
-com.thealgorithms.divideandconquer.ClosestPair=UnnecessaryFullyQualifiedName,UselessParentheses
+com.thealgorithms.divideandconquer.ClosestPair=UnnecessaryFullyQualifiedName,UselessMainMethod,UselessParentheses
 com.thealgorithms.divideandconquer.Point=UselessParentheses
+com.thealgorithms.dynamicprogramming.CatalanNumber=UselessMainMethod
+com.thealgorithms.dynamicprogramming.EggDropping=UselessMainMethod
+com.thealgorithms.dynamicprogramming.LongestPalindromicSubsequence=UselessMainMethod
 com.thealgorithms.dynamicprogramming.WineProblem=UselessParentheses
 com.thealgorithms.maths.BinomialCoefficient=UselessParentheses
 com.thealgorithms.maths.Complex=UselessParentheses
 com.thealgorithms.maths.DistanceFormulaTest=UnnecessaryFullyQualifiedName
+com.thealgorithms.maths.EulerMethod=UselessMainMethod
+com.thealgorithms.maths.GCDRecursion=UselessMainMethod
 com.thealgorithms.maths.Gaussian=UselessParentheses
 com.thealgorithms.maths.GcdSolutionWrapper=UselessParentheses
 com.thealgorithms.maths.HeronsFormula=UselessParentheses
+com.thealgorithms.maths.JugglerSequence=UselessMainMethod
 com.thealgorithms.maths.KaprekarNumbers=UselessParentheses
-com.thealgorithms.maths.KeithNumber=UselessParentheses
+com.thealgorithms.maths.KeithNumber=UselessMainMethod,UselessParentheses
 com.thealgorithms.maths.LeonardoNumber=UselessParentheses
-com.thealgorithms.maths.LinearDiophantineEquationsSolver=UselessParentheses
+com.thealgorithms.maths.LinearDiophantineEquationsSolver=UselessMainMethod,UselessParentheses
+com.thealgorithms.maths.MagicSquare=UselessMainMethod
+com.thealgorithms.maths.PiNilakantha=UselessMainMethod
+com.thealgorithms.maths.Prime.PrimeCheck=UselessMainMethod
+com.thealgorithms.maths.PythagoreanTriple=UselessMainMethod
 com.thealgorithms.maths.RomanNumeralUtil=UselessParentheses
 com.thealgorithms.maths.SecondMinMax=UselessParentheses
 com.thealgorithms.maths.SecondMinMaxTest=UnnecessaryFullyQualifiedName
+com.thealgorithms.maths.SimpsonIntegration=UselessMainMethod
 com.thealgorithms.maths.StandardDeviation=UselessParentheses
 com.thealgorithms.maths.SumOfArithmeticSeries=UselessParentheses
-com.thealgorithms.maths.TrinomialTriangle=UselessParentheses
+com.thealgorithms.maths.TrinomialTriangle=UselessMainMethod,UselessParentheses
+com.thealgorithms.maths.VectorCrossProduct=UselessMainMethod
 com.thealgorithms.maths.Volume=UselessParentheses
+com.thealgorithms.matrix.RotateMatrixBy90Degrees=UselessMainMethod
 com.thealgorithms.misc.Sparsity=UselessParentheses
-com.thealgorithms.others.CRC16=UselessParentheses
-com.thealgorithms.others.Damm=UnnecessaryFullyQualifiedName
-com.thealgorithms.others.Luhn=UnnecessaryFullyQualifiedName
-com.thealgorithms.others.Mandelbrot=UselessParentheses
-com.thealgorithms.others.MiniMaxAlgorithm=UselessParentheses
-com.thealgorithms.others.PageRank=UselessParentheses
-com.thealgorithms.others.PerlinNoise=UselessParentheses
+com.thealgorithms.others.BankersAlgorithm=UselessMainMethod
+com.thealgorithms.others.BrianKernighanAlgorithm=UselessMainMethod
+com.thealgorithms.others.CRC16=UselessMainMethod,UselessParentheses
+com.thealgorithms.others.CRC32=UselessMainMethod
+com.thealgorithms.others.Damm=UnnecessaryFullyQualifiedName,UselessMainMethod
+com.thealgorithms.others.Dijkstra=UselessMainMethod
+com.thealgorithms.others.GaussLegendre=UselessMainMethod
+com.thealgorithms.others.HappyNumbersSeq=UselessMainMethod
+com.thealgorithms.others.Huffman=UselessMainMethod
+com.thealgorithms.others.InsertDeleteInArray=UselessMainMethod
+com.thealgorithms.others.KochSnowflake=UselessMainMethod
+com.thealgorithms.others.Krishnamurthy=UselessMainMethod
+com.thealgorithms.others.LinearCongruentialGenerator=UselessMainMethod
+com.thealgorithms.others.Luhn=UnnecessaryFullyQualifiedName,UselessMainMethod
+com.thealgorithms.others.Mandelbrot=UselessMainMethod,UselessParentheses
+com.thealgorithms.others.MiniMaxAlgorithm=UselessMainMethod,UselessParentheses
+com.thealgorithms.others.PageRank=UselessMainMethod,UselessParentheses
+com.thealgorithms.others.PerlinNoise=UselessMainMethod,UselessParentheses
 com.thealgorithms.others.QueueUsingTwoStacks=UselessParentheses
-com.thealgorithms.others.Trieac=UselessParentheses
-com.thealgorithms.others.Verhoeff=UnnecessaryFullyQualifiedName
+com.thealgorithms.others.Trieac=UselessMainMethod,UselessParentheses
+com.thealgorithms.others.Verhoeff=UnnecessaryFullyQualifiedName,UselessMainMethod
+com.thealgorithms.puzzlesandgames.Sudoku=UselessMainMethod
+com.thealgorithms.searches.HowManyTimesRotated=UselessMainMethod
 com.thealgorithms.searches.InterpolationSearch=UselessParentheses
 com.thealgorithms.searches.KMPSearch=UselessParentheses
 com.thealgorithms.searches.RabinKarpAlgorithm=UselessParentheses
+com.thealgorithms.searches.RecursiveBinarySearch=UselessMainMethod
+com.thealgorithms.sorts.BogoSort=UselessMainMethod
 com.thealgorithms.sorts.CircleSort=EmptyControlStatement
 com.thealgorithms.sorts.DutchNationalFlagSort=UselessParentheses
 com.thealgorithms.sorts.MergeSortNoExtraSpace=UselessParentheses
 com.thealgorithms.sorts.RadixSort=UselessParentheses
+com.thealgorithms.sorts.TreeSort=UselessMainMethod
 com.thealgorithms.sorts.WiggleSort=UselessParentheses
+com.thealgorithms.stacks.LargestRectangle=UselessMainMethod
+com.thealgorithms.stacks.MaximumMinimumWindow=UselessMainMethod
 com.thealgorithms.stacks.PostfixToInfix=UselessParentheses
+com.thealgorithms.strings.Alphabetical=UselessMainMethod
 com.thealgorithms.strings.HorspoolSearch=UnnecessaryFullyQualifiedName,UselessParentheses
+com.thealgorithms.strings.KMP=UselessMainMethod
+com.thealgorithms.strings.Lower=UselessMainMethod
 com.thealgorithms.strings.Palindrome=UselessParentheses
+com.thealgorithms.strings.Pangram=UselessMainMethod
+com.thealgorithms.strings.RabinKarp=UselessMainMethod
+com.thealgorithms.strings.Rotation=UselessMainMethod
+com.thealgorithms.strings.Upper=UselessMainMethod
diff --git a/pom.xml b/pom.xml
index 47506868a02b..eaf71ca899cc 100644
--- a/pom.xml
+++ b/pom.xml
@@ -143,6 +143,10 @@
                 <artifactId>maven-pmd-plugin</artifactId>
                 <version>3.26.0</version>
                 <configuration>
+                    <rulesets>
+                        <ruleset>/rulesets/java/maven-pmd-plugin-default.xml</ruleset>
+                        <ruleset>file://${basedir}/pmd-custom_ruleset.xml</ruleset>
+                    </rulesets>
                     <printFailingErrors>true</printFailingErrors>
                     <includeTests>true</includeTests>
                     <linkXRef>false</linkXRef>

From 0b21bb0a3851e16f2386074e72ea25a7736bc39f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pau=20L=C3=B3pez=20N=C3=BA=C3=B1ez?=
 <paulopeznunez@gmail.com>
Date: Wed, 11 Jun 2025 17:37:42 +0200
Subject: [PATCH 0813/1338] Add Boyer-Moore string search algorithm with JUnit
 tests (#6274)

---
 .../thealgorithms/searches/BoyerMoore.java    | 58 +++++++++++++++++++
 .../searches/BoyerMooreTest.java              | 55 ++++++++++++++++++
 2 files changed, 113 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/searches/BoyerMoore.java
 create mode 100644 src/test/java/com/thealgorithms/searches/BoyerMooreTest.java

diff --git a/src/main/java/com/thealgorithms/searches/BoyerMoore.java b/src/main/java/com/thealgorithms/searches/BoyerMoore.java
new file mode 100644
index 000000000000..6998021503cc
--- /dev/null
+++ b/src/main/java/com/thealgorithms/searches/BoyerMoore.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.searches;
+
+/**
+ * Boyer-Moore string search algorithm.
+ * Efficient algorithm for substring search.
+ * https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_string-search_algorithm
+ */
+public class BoyerMoore {
+
+    private final int radix; // Radix (number of possible characters)
+    private final int[] right; // Bad character rule table
+    private final String pattern;
+
+    public BoyerMoore(String pat) {
+        this.pattern = pat;
+        this.radix = 256;
+        this.right = new int[radix];
+
+        for (int c = 0; c < radix; c++) {
+            right[c] = -1;
+        }
+
+        for (int j = 0; j < pat.length(); j++) {
+            right[pat.charAt(j)] = j;
+        }
+    }
+
+    public int search(String text) {
+        if (pattern.isEmpty()) {
+            return 0;
+        }
+
+        int m = pattern.length();
+        int n = text.length();
+
+        int skip;
+        for (int i = 0; i <= n - m; i += skip) {
+            skip = 0;
+            for (int j = m - 1; j >= 0; j--) {
+                char txtChar = text.charAt(i + j);
+                char patChar = pattern.charAt(j);
+                if (patChar != txtChar) {
+                    skip = Math.max(1, j - right[txtChar]);
+                    break;
+                }
+            }
+            if (skip == 0) {
+                return i; // Match found
+            }
+        }
+
+        return -1; // No match
+    }
+
+    public static int staticSearch(String text, String pattern) {
+        return new BoyerMoore(pattern).search(text);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/searches/BoyerMooreTest.java b/src/test/java/com/thealgorithms/searches/BoyerMooreTest.java
new file mode 100644
index 000000000000..9021eacbb8ee
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/BoyerMooreTest.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class BoyerMooreTest {
+
+    @Test
+    public void testPatternFound() {
+        BoyerMoore bm = new BoyerMoore("ABCDABD");
+        String text = "ABC ABCDAB ABCDABCDABDE";
+        int index = bm.search(text);
+        assertEquals(15, index);
+    }
+
+    @Test
+    public void testPatternNotFound() {
+        BoyerMoore bm = new BoyerMoore("XYZ");
+        String text = "ABC ABCDAB ABCDABCDABDE";
+        int index = bm.search(text);
+        assertEquals(-1, index);
+    }
+
+    @Test
+    public void testPatternAtBeginning() {
+        BoyerMoore bm = new BoyerMoore("ABC");
+        String text = "ABCDEF";
+        int index = bm.search(text);
+        assertEquals(0, index);
+    }
+
+    @Test
+    public void testPatternAtEnd() {
+        BoyerMoore bm = new BoyerMoore("CDE");
+        String text = "ABCDEFGCDE";
+        int index = bm.search(text);
+        assertEquals(2, index); // Primera ocurrencia de "CDE"
+    }
+
+    @Test
+    public void testEmptyPattern() {
+        BoyerMoore bm = new BoyerMoore("");
+        String text = "Hello world";
+        int index = bm.search(text);
+        assertEquals(0, index);
+    }
+
+    @Test
+    public void testStaticSearchMethod() {
+        String text = "ABCDEFGCDE";
+        int index = BoyerMoore.staticSearch(text, "CDE");
+        assertEquals(2, index); // Primera ocurrencia de "CDE"
+    }
+}

From 1745d19f09f636657c45e1f341e9f8d10357a687 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Wed, 11 Jun 2025 19:04:06 +0200
Subject: [PATCH 0814/1338] refactor: unified duplicate Anagram classes into a
 single implementation (#6290)

---
 .../dynamicprogramming/UniquePaths.java       |   9 +-
 .../dynamicprogramming/WildcardMatching.java  |   5 +-
 .../thealgorithms/maths/DudeneyNumber.java    |   4 +-
 .../scheduling/RRScheduling.java              |   5 +-
 .../com/thealgorithms/strings/Anagrams.java   |  35 +++---
 .../thealgorithms/strings/CheckAnagrams.java  | 110 ------------------
 .../thealgorithms/strings/AnagramsTest.java   |  13 ++-
 ...rSameTest.java => CharactersSameTest.java} |   0
 .../strings/CheckAnagramsTest.java            |  69 -----------
 9 files changed, 38 insertions(+), 212 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/strings/CheckAnagrams.java
 rename src/test/java/com/thealgorithms/strings/{CharacterSameTest.java => CharactersSameTest.java} (100%)
 delete mode 100644 src/test/java/com/thealgorithms/strings/CheckAnagramsTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java b/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java
index 80b553f2744c..22ad8a7dd8e3 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java
@@ -1,3 +1,7 @@
+package com.thealgorithms.dynamicprogramming;
+
+import java.util.Arrays;
+
 /**
  * Author: Siddhant Swarup Mallick
  * Github: https://github.com/siddhant2002
@@ -12,11 +16,6 @@
  * This program calculates the number of unique paths possible for a robot to reach the bottom-right corner
  * of an m x n grid using dynamic programming.
  */
-
-package com.thealgorithms.dynamicprogramming;
-
-import java.util.Arrays;
-
 public final class UniquePaths {
 
     private UniquePaths() {
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java b/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java
index 8e8bf3cc6606..8658ea30af00 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java
@@ -1,3 +1,5 @@
+package com.thealgorithms.dynamicprogramming;
+
 /**
  *
  * Author: Janmesh Singh
@@ -11,9 +13,6 @@
  * Use DP to return True if the pattern matches the entire text and False otherwise
  *
  */
-
-package com.thealgorithms.dynamicprogramming;
-
 public final class WildcardMatching {
     private WildcardMatching() {
     }
diff --git a/src/main/java/com/thealgorithms/maths/DudeneyNumber.java b/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
index acf1e55d49c8..37f28e188663 100644
--- a/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/DudeneyNumber.java
@@ -1,11 +1,11 @@
+package com.thealgorithms.maths;
+
 /**
  * A number is said to be Dudeney if the sum of the digits, is the cube root of the entered number.
  * Example- Let the number be 512, its sum of digits is 5+1+2=8. The cube root of 512 is also 8.
  *          Since, the sum of the digits is equal to the cube root of the entered number;
  *          it is a Dudeney Number.
  */
-package com.thealgorithms.maths;
-
 public final class DudeneyNumber {
     private DudeneyNumber() {
     }
diff --git a/src/main/java/com/thealgorithms/scheduling/RRScheduling.java b/src/main/java/com/thealgorithms/scheduling/RRScheduling.java
index 110c97416a42..05efe1d59141 100644
--- a/src/main/java/com/thealgorithms/scheduling/RRScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/RRScheduling.java
@@ -1,7 +1,3 @@
-/**
- * @author Md Asif Joardar
- */
-
 package com.thealgorithms.scheduling;
 
 import com.thealgorithms.devutils.entities.ProcessDetails;
@@ -11,6 +7,7 @@
 import java.util.Queue;
 
 /**
+ * @author Md Asif Joardar
  * The Round-robin scheduling algorithm is a kind of preemptive First come, First Serve CPU
  * Scheduling algorithm. This can be understood here -
  * https://www.scaler.com/topics/round-robin-scheduling-in-os/
diff --git a/src/main/java/com/thealgorithms/strings/Anagrams.java b/src/main/java/com/thealgorithms/strings/Anagrams.java
index 4b24979e2689..5b97af0758f2 100644
--- a/src/main/java/com/thealgorithms/strings/Anagrams.java
+++ b/src/main/java/com/thealgorithms/strings/Anagrams.java
@@ -23,7 +23,9 @@ private Anagrams() {
      * @param t the second string
      * @return true if the strings are anagrams, false otherwise
      */
-    public static boolean approach1(String s, String t) {
+    public static boolean areAnagramsBySorting(String s, String t) {
+        s = s.toLowerCase().replaceAll("[^a-z]", "");
+        t = t.toLowerCase().replaceAll("[^a-z]", "");
         if (s.length() != t.length()) {
             return false;
         }
@@ -43,17 +45,18 @@ public static boolean approach1(String s, String t) {
      * @param t the second string
      * @return true if the strings are anagrams, false otherwise
      */
-    public static boolean approach2(String s, String t) {
-        if (s.length() != t.length()) {
-            return false;
+    public static boolean areAnagramsByCountingChars(String s, String t) {
+        s = s.toLowerCase().replaceAll("[^a-z]", "");
+        t = t.toLowerCase().replaceAll("[^a-z]", "");
+        int[] dict = new int[128];
+        for (char ch : s.toCharArray()) {
+            dict[ch]++;
         }
-        int[] charCount = new int[26];
-        for (int i = 0; i < s.length(); i++) {
-            charCount[s.charAt(i) - 'a']++;
-            charCount[t.charAt(i) - 'a']--;
+        for (char ch : t.toCharArray()) {
+            dict[ch]--;
         }
-        for (int count : charCount) {
-            if (count != 0) {
+        for (int e : dict) {
+            if (e != 0) {
                 return false;
             }
         }
@@ -70,7 +73,9 @@ public static boolean approach2(String s, String t) {
      * @param t the second string
      * @return true if the strings are anagrams, false otherwise
      */
-    public static boolean approach3(String s, String t) {
+    public static boolean areAnagramsByCountingCharsSingleArray(String s, String t) {
+        s = s.toLowerCase().replaceAll("[^a-z]", "");
+        t = t.toLowerCase().replaceAll("[^a-z]", "");
         if (s.length() != t.length()) {
             return false;
         }
@@ -96,7 +101,9 @@ public static boolean approach3(String s, String t) {
      * @param t the second string
      * @return true if the strings are anagrams, false otherwise
      */
-    public static boolean approach4(String s, String t) {
+    public static boolean areAnagramsUsingHashMap(String s, String t) {
+        s = s.toLowerCase().replaceAll("[^a-z]", "");
+        t = t.toLowerCase().replaceAll("[^a-z]", "");
         if (s.length() != t.length()) {
             return false;
         }
@@ -123,7 +130,9 @@ public static boolean approach4(String s, String t) {
      * @param t the second string
      * @return true if the strings are anagrams, false otherwise
      */
-    public static boolean approach5(String s, String t) {
+    public static boolean areAnagramsBySingleFreqArray(String s, String t) {
+        s = s.toLowerCase().replaceAll("[^a-z]", "");
+        t = t.toLowerCase().replaceAll("[^a-z]", "");
         if (s.length() != t.length()) {
             return false;
         }
diff --git a/src/main/java/com/thealgorithms/strings/CheckAnagrams.java b/src/main/java/com/thealgorithms/strings/CheckAnagrams.java
deleted file mode 100644
index 7bf7cd9a7c66..000000000000
--- a/src/main/java/com/thealgorithms/strings/CheckAnagrams.java
+++ /dev/null
@@ -1,110 +0,0 @@
-package com.thealgorithms.strings;
-
-import java.util.HashMap;
-import java.util.Map;
-
-/**
- * Two strings are anagrams if they are made of the same letters arranged
- * differently (ignoring the case).
- */
-public final class CheckAnagrams {
-    private CheckAnagrams() {
-    }
-    /**
-     * Check if two strings are anagrams or not
-     *
-     * @param s1 the first string
-     * @param s2 the second string
-     * @return {@code true} if two string are anagrams, otherwise {@code false}
-     */
-    public static boolean isAnagrams(String s1, String s2) {
-        int l1 = s1.length();
-        int l2 = s2.length();
-        s1 = s1.toLowerCase();
-        s2 = s2.toLowerCase();
-        Map<Character, Integer> charAppearances = new HashMap<>();
-
-        for (int i = 0; i < l1; i++) {
-            char c = s1.charAt(i);
-            int numOfAppearances = charAppearances.getOrDefault(c, 0);
-            charAppearances.put(c, numOfAppearances + 1);
-        }
-
-        for (int i = 0; i < l2; i++) {
-            char c = s2.charAt(i);
-            if (!charAppearances.containsKey(c)) {
-                return false;
-            }
-            charAppearances.put(c, charAppearances.get(c) - 1);
-        }
-
-        for (int cnt : charAppearances.values()) {
-            if (cnt != 0) {
-                return false;
-            }
-        }
-        return true;
-    }
-
-    /**
-     * If given strings contain Unicode symbols.
-     * The first 128 ASCII codes are identical to Unicode.
-     * This algorithm is case-sensitive.
-     *
-     * @param s1 the first string
-     * @param s2 the second string
-     * @return true if two string are anagrams, otherwise false
-     */
-    public static boolean isAnagramsUnicode(String s1, String s2) {
-        int[] dict = new int[128];
-        for (char ch : s1.toCharArray()) {
-            dict[ch]++;
-        }
-        for (char ch : s2.toCharArray()) {
-            dict[ch]--;
-        }
-        for (int e : dict) {
-            if (e != 0) {
-                return false;
-            }
-        }
-        return true;
-    }
-
-    /**
-     * If given strings contain only lowercase English letters.
-     * <p>
-     * The main "trick":
-     * To map each character from the first string 's1' we need to subtract an integer value of 'a' character
-     * as 'dict' array starts with 'a' character.
-     *
-     * @param s1 the first string
-     * @param s2 the second string
-     * @return true if two string are anagrams, otherwise false
-     */
-    public static boolean isAnagramsOptimised(String s1, String s2) {
-        // 26 - English alphabet length
-        int[] dict = new int[26];
-        for (char ch : s1.toCharArray()) {
-            checkLetter(ch);
-            dict[ch - 'a']++;
-        }
-        for (char ch : s2.toCharArray()) {
-            checkLetter(ch);
-            dict[ch - 'a']--;
-        }
-        for (int e : dict) {
-            if (e != 0) {
-                return false;
-            }
-        }
-        return true;
-    }
-
-    private static void checkLetter(char ch) {
-        int index = ch - 'a';
-        if (index < 0 || index >= 26) {
-            throw new IllegalArgumentException("Strings must contain only lowercase English letters!");
-        }
-    }
-}
diff --git a/src/test/java/com/thealgorithms/strings/AnagramsTest.java b/src/test/java/com/thealgorithms/strings/AnagramsTest.java
index 88f6e0bb72ec..fa8ea72f2b8c 100644
--- a/src/test/java/com/thealgorithms/strings/AnagramsTest.java
+++ b/src/test/java/com/thealgorithms/strings/AnagramsTest.java
@@ -13,36 +13,37 @@ record AnagramTestCase(String input1, String input2, boolean expected) {
 
     private static Stream<AnagramTestCase> anagramTestData() {
         return Stream.of(new AnagramTestCase("late", "tale", true), new AnagramTestCase("late", "teal", true), new AnagramTestCase("listen", "silent", true), new AnagramTestCase("hello", "olelh", true), new AnagramTestCase("hello", "world", false), new AnagramTestCase("deal", "lead", true),
-            new AnagramTestCase("binary", "brainy", true), new AnagramTestCase("adobe", "abode", true), new AnagramTestCase("cat", "act", true), new AnagramTestCase("cat", "cut", false));
+            new AnagramTestCase("binary", "brainy", true), new AnagramTestCase("adobe", "abode", true), new AnagramTestCase("cat", "act", true), new AnagramTestCase("cat", "cut", false), new AnagramTestCase("Listen", "Silent", true), new AnagramTestCase("Dormitory", "DirtyRoom", true),
+            new AnagramTestCase("Schoolmaster", "TheClassroom", true), new AnagramTestCase("Astronomer", "MoonStarer", true), new AnagramTestCase("Conversation", "VoicesRantOn", true));
     }
 
     @ParameterizedTest
     @MethodSource("anagramTestData")
     void testApproach1(AnagramTestCase testCase) {
-        assertEquals(testCase.expected(), Anagrams.approach1(testCase.input1(), testCase.input2()));
+        assertEquals(testCase.expected(), Anagrams.areAnagramsBySorting(testCase.input1(), testCase.input2()));
     }
 
     @ParameterizedTest
     @MethodSource("anagramTestData")
     void testApproach2(AnagramTestCase testCase) {
-        assertEquals(testCase.expected(), Anagrams.approach2(testCase.input1(), testCase.input2()));
+        assertEquals(testCase.expected(), Anagrams.areAnagramsByCountingChars(testCase.input1(), testCase.input2()));
     }
 
     @ParameterizedTest
     @MethodSource("anagramTestData")
     void testApproach3(AnagramTestCase testCase) {
-        assertEquals(testCase.expected(), Anagrams.approach3(testCase.input1(), testCase.input2()));
+        assertEquals(testCase.expected(), Anagrams.areAnagramsByCountingCharsSingleArray(testCase.input1(), testCase.input2()));
     }
 
     @ParameterizedTest
     @MethodSource("anagramTestData")
     void testApproach4(AnagramTestCase testCase) {
-        assertEquals(testCase.expected(), Anagrams.approach4(testCase.input1(), testCase.input2()));
+        assertEquals(testCase.expected(), Anagrams.areAnagramsUsingHashMap(testCase.input1(), testCase.input2()));
     }
 
     @ParameterizedTest
     @MethodSource("anagramTestData")
     void testApproach5(AnagramTestCase testCase) {
-        assertEquals(testCase.expected(), Anagrams.approach5(testCase.input1(), testCase.input2()));
+        assertEquals(testCase.expected(), Anagrams.areAnagramsBySingleFreqArray(testCase.input1(), testCase.input2()));
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/CharacterSameTest.java b/src/test/java/com/thealgorithms/strings/CharactersSameTest.java
similarity index 100%
rename from src/test/java/com/thealgorithms/strings/CharacterSameTest.java
rename to src/test/java/com/thealgorithms/strings/CharactersSameTest.java
diff --git a/src/test/java/com/thealgorithms/strings/CheckAnagramsTest.java b/src/test/java/com/thealgorithms/strings/CheckAnagramsTest.java
deleted file mode 100644
index 82a75a130ef0..000000000000
--- a/src/test/java/com/thealgorithms/strings/CheckAnagramsTest.java
+++ /dev/null
@@ -1,69 +0,0 @@
-package com.thealgorithms.strings;
-
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
-import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
-
-public class CheckAnagramsTest {
-    private static final String MESSAGE = "Strings must contain only lowercase English letters!";
-
-    // CHECK METHOD isAnagrams()
-    @Test
-    public void testCheckAnagrams() {
-        String testString1 = "STUDY";
-        String testString2 = "DUSTY";
-        Assertions.assertTrue(CheckAnagrams.isAnagrams(testString1, testString2));
-    }
-
-    @Test
-    public void testCheckFalseAnagrams() {
-        String testString1 = "STUDY";
-        String testString2 = "random";
-        Assertions.assertFalse(CheckAnagrams.isAnagrams(testString1, testString2));
-    }
-
-    @Test
-    public void testCheckSameWordAnagrams() {
-        String testString1 = "STUDY";
-        Assertions.assertTrue(CheckAnagrams.isAnagrams(testString1, testString1));
-    }
-
-    @Test
-    public void testCheckDifferentCasesAnagram() {
-        String testString1 = "STUDY";
-        String testString2 = "dusty";
-        Assertions.assertTrue(CheckAnagrams.isAnagrams(testString1, testString2));
-    }
-
-    // CHECK METHOD isAnagramsUnicode()
-    // Below tests work with strings which consist of Unicode symbols & the algorithm is case-sensitive.
-    @Test
-    public void testStringAreValidAnagramsCaseSensitive() {
-        Assertions.assertTrue(CheckAnagrams.isAnagramsUnicode("Silent", "liSten"));
-        Assertions.assertTrue(CheckAnagrams.isAnagramsUnicode("This is a string", "is This a string"));
-    }
-
-    @Test
-    public void testStringAreNotAnagramsCaseSensitive() {
-        Assertions.assertFalse(CheckAnagrams.isAnagramsUnicode("Silent", "Listen"));
-        Assertions.assertFalse(CheckAnagrams.isAnagramsUnicode("This is a string", "Is this a string"));
-    }
-
-    // CHECK METHOD isAnagramsOptimised()
-    // Below tests work with strings which consist of only lowercase English letters
-    @Test
-    public void testOptimisedAlgorithmStringsAreValidAnagrams() {
-        Assertions.assertTrue(CheckAnagrams.isAnagramsOptimised("silent", "listen"));
-        Assertions.assertTrue(CheckAnagrams.isAnagramsOptimised("mam", "amm"));
-    }
-
-    @Test
-    public void testOptimisedAlgorithmShouldThrowExceptionWhenStringsContainUppercaseLetters() {
-        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> CheckAnagrams.isAnagramsOptimised("Silent", "Listen"));
-        Assertions.assertEquals(exception.getMessage(), MESSAGE);
-
-        exception = assertThrows(IllegalArgumentException.class, () -> Assertions.assertFalse(CheckAnagrams.isAnagramsOptimised("This is a string", "Is this a string")));
-        Assertions.assertEquals(exception.getMessage(), MESSAGE);
-    }
-}

From b427b40f5637d30e36a41ade79fa42dea424604c Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 12 Jun 2025 17:35:01 +0200
Subject: [PATCH 0815/1338] chore: monitor structure of the project (#6291)

---
 .github/workflows/project_structure.yml      | 22 ++++++++++++++++
 .github/workflows/scripts/check_structure.py | 27 ++++++++++++++++++++
 2 files changed, 49 insertions(+)
 create mode 100644 .github/workflows/project_structure.yml
 create mode 100644 .github/workflows/scripts/check_structure.py

diff --git a/.github/workflows/project_structure.yml b/.github/workflows/project_structure.yml
new file mode 100644
index 000000000000..def01554a4f8
--- /dev/null
+++ b/.github/workflows/project_structure.yml
@@ -0,0 +1,22 @@
+---
+name: ProjectStructure
+
+'on':
+  workflow_dispatch:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  check_structure:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
+
+      - name: Check project structure
+        run: python3 .github/workflows/scripts/check_structure.py
+...
diff --git a/.github/workflows/scripts/check_structure.py b/.github/workflows/scripts/check_structure.py
new file mode 100644
index 000000000000..914f64369207
--- /dev/null
+++ b/.github/workflows/scripts/check_structure.py
@@ -0,0 +1,27 @@
+import pathlib
+import sys
+
+
+def _is_java_file_properly_located(java_file: pathlib.Path) -> bool:
+    main_parents = java_file.parent.parents
+    return (
+        pathlib.Path("src/main/java/com/thealgorithms/") in main_parents
+        or pathlib.Path("src/test/java/com/thealgorithms/") in main_parents
+    )
+
+
+def _find_misplaced_java_files() -> list[pathlib.Path]:
+    return [
+        java_file
+        for java_file in pathlib.Path(".").rglob("*.java")
+        if not _is_java_file_properly_located(java_file)
+    ]
+
+
+if __name__ == "__main__":
+    misplaced_files = _find_misplaced_java_files()
+    if misplaced_files:
+        print("The following java files are not located in the correct directory:")
+        for _ in misplaced_files:
+            print(_)
+        sys.exit(1)

From a21abe6b2b6fe7a0d42804c9f5e09422c1954098 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 14 Jun 2025 18:42:45 +0200
Subject: [PATCH 0816/1338] chore: add `security` ruleset to PMD (#6292)

---
 pom.xml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pom.xml b/pom.xml
index eaf71ca899cc..a87a7157c2f9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -145,6 +145,7 @@
                 <configuration>
                     <rulesets>
                         <ruleset>/rulesets/java/maven-pmd-plugin-default.xml</ruleset>
+                        <ruleset>/category/java/security.xml</ruleset>
                         <ruleset>file://${basedir}/pmd-custom_ruleset.xml</ruleset>
                     </rulesets>
                     <printFailingErrors>true</printFailingErrors>

From 616d15a40828d4b2399e637e6f2fe9e112677b9e Mon Sep 17 00:00:00 2001
From: 02RdDT <61636396+DomTr@users.noreply.github.com>
Date: Wed, 18 Jun 2025 22:29:35 +0300
Subject: [PATCH 0817/1338] Shortest coprime segment using sliding window
 technique (#6296)

* Shortest coprime segment using sliding window technique

* mvn checkstyle passes

* gcd function reformatted

* fixed typo in ShortestCoprimeSegment

* 1. shortestCoprimeSegment now returns not the length, but the shortest segment itself.
2. Testcases have been adapted, a few new ones added.

* clang formatted ShortestCoprimeSegmentTest.java code
---
 .../slidingwindow/ShortestCoprimeSegment.java | 135 ++++++++++++++++++
 .../ShortestCoprimeSegmentTest.java           |  65 +++++++++
 2 files changed, 200 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegment.java
 create mode 100644 src/test/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegmentTest.java

diff --git a/src/main/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegment.java b/src/main/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegment.java
new file mode 100644
index 000000000000..b99f7ca7d62f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegment.java
@@ -0,0 +1,135 @@
+package com.thealgorithms.slidingwindow;
+
+import java.util.Arrays;
+import java.util.LinkedList;
+
+/**
+ * The Sliding Window technique together with 2-stack technique is used to find coprime segment of minimal size in an array.
+ * Segment a[i],...,a[i+l] is coprime if gcd(a[i], a[i+1], ..., a[i+l]) = 1
+ * <p>
+ * Run-time complexity: O(n log n)
+ * What is special about this 2-stack technique is that it enables us to remove element a[i] and find gcd(a[i+1],...,a[i+l]) in amortized O(1) time.
+ * For 'remove' worst-case would be O(n) operation, but this happens rarely.
+ * Main observation is that each element gets processed a constant amount of times, hence complexity will be:
+ * O(n log n), where log n comes from complexity of gcd.
+ * <p>
+ * More generally, the 2-stack technique enables us to 'remove' an element fast if it is known how to 'add' an element fast to the set.
+ * In our case 'adding' is calculating d' = gcd(a[i],...,a[i+l+1]), when d = gcd(a[i],...a[i]) with d' = gcd(d, a[i+l+1]).
+ * and removing is find gcd(a[i+1],...,a[i+l]). We don't calculate it explicitly, but it is pushed in the stack which we can pop in O(1).
+ * <p>
+ * One can change methods 'legalSegment' and function 'f' in DoubleStack to adapt this code to other sliding-window type problems.
+ * I recommend this article for more explanations: "<a href="https://codeforces.com/edu/course/2/lesson/9/2">CF Article</a>">Article 1</a> or <a href="https://usaco.guide/gold/sliding-window?lang=cpp#method-2---two-stacks">USACO Article</a>
+ * <p>
+ * Another method to solve this problem is through segment trees. Then query operation would have O(log n), not O(1) time, but runtime complexity would still be O(n log n)
+ *
+ * @author DomTr (<a href="https://github.com/DomTr">Github</a>)
+ */
+public final class ShortestCoprimeSegment {
+    // Prevent instantiation
+    private ShortestCoprimeSegment() {
+    }
+
+    /**
+     * @param arr is the input array
+     * @return shortest segment in the array which has gcd equal to 1. If no such segment exists or array is empty, returns empty array
+     */
+    public static long[] shortestCoprimeSegment(long[] arr) {
+        if (arr == null || arr.length == 0) {
+            return new long[] {};
+        }
+        DoubleStack front = new DoubleStack();
+        DoubleStack back = new DoubleStack();
+        int n = arr.length;
+        int l = 0;
+        int shortestLength = n + 1;
+        int beginsAt = -1; // beginning index of the shortest coprime segment
+        for (int i = 0; i < n; i++) {
+            back.push(arr[i]);
+            while (legalSegment(front, back)) {
+                remove(front, back);
+                if (shortestLength > i - l + 1) {
+                    beginsAt = l;
+                    shortestLength = i - l + 1;
+                }
+                l++;
+            }
+        }
+        if (shortestLength > n) {
+            shortestLength = -1;
+        }
+        if (shortestLength == -1) {
+            return new long[] {};
+        }
+        return Arrays.copyOfRange(arr, beginsAt, beginsAt + shortestLength);
+    }
+
+    private static boolean legalSegment(DoubleStack front, DoubleStack back) {
+        return gcd(front.top(), back.top()) == 1;
+    }
+
+    private static long gcd(long a, long b) {
+        if (a < b) {
+            return gcd(b, a);
+        } else if (b == 0) {
+            return a;
+        } else {
+            return gcd(a % b, b);
+        }
+    }
+
+    /**
+     * This solves the problem of removing elements quickly.
+     * Even though the worst case of 'remove' method is O(n), it is a very pessimistic view.
+     * We will need to empty out 'back', only when 'from' is empty.
+     * Consider element x when it is added to stack 'back'.
+     * After some time 'front' becomes empty and x goes to 'front'. Notice that in the for-loop we proceed further and x will  never come back to any stacks 'back' or 'front'.
+     * In other words, every element gets processed by a constant number of operations.
+     * So 'remove' amortized runtime is actually O(n).
+     */
+    private static void remove(DoubleStack front, DoubleStack back) {
+        if (front.isEmpty()) {
+            while (!back.isEmpty()) {
+                front.push(back.pop());
+            }
+        }
+        front.pop();
+    }
+
+    /**
+     * DoubleStack serves as a collection of two stacks. One is a normal stack called 'stack', the other 'values' stores gcd-s up until some index.
+     */
+    private static class DoubleStack {
+        LinkedList<Long> stack;
+        LinkedList<Long> values;
+
+        DoubleStack() {
+            values = new LinkedList<>();
+            stack = new LinkedList<>();
+            values.add(0L); // Initialise with 0 which is neutral element in terms of gcd, i.e. gcd(a,0) = a
+        }
+
+        long f(long a, long b) { // Can be replaced with other function
+            return gcd(a, b);
+        }
+
+        public void push(long x) {
+            stack.addLast(x);
+            values.addLast(f(values.getLast(), x));
+        }
+
+        public long top() {
+            return values.getLast();
+        }
+
+        public long pop() {
+            long res = stack.getLast();
+            stack.removeLast();
+            values.removeLast();
+            return res;
+        }
+
+        public boolean isEmpty() {
+            return stack.isEmpty();
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegmentTest.java b/src/test/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegmentTest.java
new file mode 100644
index 000000000000..acb9e1e30ac7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegmentTest.java
@@ -0,0 +1,65 @@
+package com.thealgorithms.slidingwindow;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.Arrays;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for ShortestCoprimeSegment algorithm
+ *
+ * @author DomTr (<a href="https://github.com/DomTr">...</a>)
+ */
+public class ShortestCoprimeSegmentTest {
+    @Test
+    public void testShortestCoprimeSegment() {
+        assertArrayEquals(new long[] {4, 6, 9}, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {4, 6, 9, 3, 6}));
+        assertArrayEquals(new long[] {4, 5}, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {4, 5, 9, 3, 6}));
+        assertArrayEquals(new long[] {3, 2}, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {3, 2}));
+        assertArrayEquals(new long[] {9, 10}, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {3, 9, 9, 9, 10}));
+
+        long[] test5 = new long[] {3 * 11, 11 * 7, 11 * 7 * 3, 11 * 7 * 3 * 5, 11 * 7 * 3 * 5 * 13, 7 * 13, 11 * 7 * 3 * 5 * 13};
+        long[] answer5 = Arrays.copyOfRange(test5, 0, test5.length - 1);
+        assertArrayEquals(answer5, ShortestCoprimeSegment.shortestCoprimeSegment(test5));
+
+        // Test suite, when the entire array needs to be taken
+        long[] test6 = new long[] {3 * 7, 7 * 5, 5 * 7 * 3, 3 * 5};
+        assertArrayEquals(test6, ShortestCoprimeSegment.shortestCoprimeSegment(test6));
+
+        long[] test7 = new long[] {3 * 11, 11 * 7, 11 * 7 * 3, 3 * 7};
+        assertArrayEquals(test7, ShortestCoprimeSegment.shortestCoprimeSegment(test7));
+
+        long[] test8 = new long[] {3 * 11, 11 * 7, 11 * 7 * 3, 11 * 7 * 3 * 5, 5 * 7};
+        assertArrayEquals(test8, ShortestCoprimeSegment.shortestCoprimeSegment(test8));
+
+        long[] test9 = new long[] {3 * 11, 11 * 7, 11 * 7 * 3, 11 * 7 * 3 * 5, 11 * 7 * 3 * 5 * 13, 7 * 13};
+        assertArrayEquals(test9, ShortestCoprimeSegment.shortestCoprimeSegment(test9));
+
+        long[] test10 = new long[] {3 * 11, 7 * 11, 3 * 7 * 11, 3 * 5 * 7 * 11, 3 * 5 * 7 * 11 * 13, 2 * 3 * 5 * 7 * 11 * 13, 2 * 3 * 5 * 7 * 11 * 13 * 17, 2 * 3 * 5 * 7 * 11 * 13 * 17 * 19, 2 * 3 * 5 * 7 * 11 * 13 * 17 * 19 * 23, 7 * 13};
+        assertArrayEquals(test10, ShortestCoprimeSegment.shortestCoprimeSegment(test10));
+
+        // Segment can consist of one element
+        long[] test11 = new long[] {1};
+        assertArrayEquals(test11, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {4, 6, 1, 3, 6}));
+        long[] test12 = new long[] {1};
+        assertArrayEquals(test12, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {1}));
+    }
+    @Test
+    public void testShortestCoprimeSegment2() {
+        assertArrayEquals(new long[] {2 * 3, 2 * 3 * 5, 2 * 3 * 5 * 7, 5 * 7}, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {2 * 3, 2 * 3 * 5, 2 * 3 * 5 * 7, 5 * 7, 2 * 3 * 5 * 7}));
+        assertArrayEquals(new long[] {5 * 7, 2}, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {2 * 3, 2 * 3 * 5, 2 * 3 * 5 * 7, 5 * 7, 2}));
+        assertArrayEquals(new long[] {5 * 7, 2 * 5 * 7, 2 * 11}, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {2 * 3, 2 * 3 * 5, 2 * 3 * 5 * 7, 5 * 7, 2 * 5 * 7, 2 * 11}));
+        assertArrayEquals(new long[] {3 * 5 * 7, 2 * 3, 2}, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {2, 2 * 3, 2 * 3 * 5, 3 * 5 * 7, 2 * 3, 2}));
+    }
+    @Test
+    public void testNoCoprimeSegment() {
+        // There may not be a coprime segment
+        long[] empty = new long[] {};
+        assertArrayEquals(empty, ShortestCoprimeSegment.shortestCoprimeSegment(null));
+        assertArrayEquals(empty, ShortestCoprimeSegment.shortestCoprimeSegment(empty));
+        assertArrayEquals(empty, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {4, 6, 8, 12, 8}));
+        assertArrayEquals(empty, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {4, 4, 4, 4, 10, 4, 6, 8, 12, 8}));
+        assertArrayEquals(empty, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {100}));
+        assertArrayEquals(empty, ShortestCoprimeSegment.shortestCoprimeSegment(new long[] {2, 2, 2}));
+    }
+}

From ae718618eaf3aae55eaa409a36b29b9ab3a633bb Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 19 Jun 2025 00:18:27 +0200
Subject: [PATCH 0818/1338] chore(deps): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.6.10 to 7.6.11 (#6297)

chore(deps): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.6.10 to 7.6.11.
- [Commits](https://github.com/mebigfatguy/fb-contrib/commits)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.6.11
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index a87a7157c2f9..37a8940000c9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -128,7 +128,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.10</version>
+                            <version>7.6.11</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

From 13d8a28e47c0da3fa157217b84b0cf3fc9765605 Mon Sep 17 00:00:00 2001
From: Rahul <135102753+Rahul-18r@users.noreply.github.com>
Date: Sat, 21 Jun 2025 01:37:58 +0530
Subject: [PATCH 0819/1338] Update DIRECTORY.md with Newly Added Files (#6302)

* Update DIRECTORY.md with newly added files

* Add files_local.txt to .gitignore

* Update .gitignore

* Delete .gitignore

* Updated .gitignore

* Update .gitignore
---
 DIRECTORY.md | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index fe9e440da3e2..5cc12315d10b 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -204,6 +204,7 @@
               * [RotateSinglyLinkedLists](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java)
               * [SearchSinglyLinkedListRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java)
               * [SinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java)
+              * [SinglyLinkedListNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedListNode.java)
               * [SkipList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java)
               * [SortedLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java)
             * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/Node.java)
@@ -233,6 +234,7 @@
               * [BSTIterative](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTIterative.java)
               * [BSTRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursive.java)
               * [BSTRecursiveGeneric](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java)
+              * [BTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BTree.java)
               * [CeilInBinarySearchTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java)
               * [CheckBinaryTreeIsValidBST](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBST.java)
               * [CheckIfBinaryTreeBalanced](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalanced.java)
@@ -302,6 +304,7 @@
             * [LongestArithmeticSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java)
             * [LongestCommonSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java)
             * [LongestIncreasingSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java)
+            * [LongestIncreasingSubsequenceNLogN](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogN.java)
             * [LongestPalindromicSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java)
             * [LongestPalindromicSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java)
             * [LongestValidParentheses](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestValidParentheses.java)
@@ -337,6 +340,7 @@
           * graph
             * [ConstrainedShortestPath](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java)
             * [StronglyConnectedComponentOptimized](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
+            * [TravelingSalesman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/TravelingSalesman.java)
           * greedyalgorithms
             * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
             * [BandwidthAllocation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java)
@@ -488,6 +492,7 @@
             * [MirrorOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java)
             * [PrintAMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java)
             * [RotateMatrixBy90Degrees](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java)
+            * [SolveSystem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/SolveSystem.java)
             * utils
               * [MatrixUtil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/utils/MatrixUtil.java)
           * misc
@@ -552,6 +557,11 @@
             * [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java)
             * [TowerOfHanoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java)
             * [WordBoggle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/puzzlesandgames/WordBoggle.java)
+          * randomized
+            * [KargerMinCut](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/randomized/KargerMinCut.java)
+            * [MonteCarloIntegration](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java)
+            * [RandomizedQuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/randomized/RandomizedQuickSort.java)
+            * [ReservoirSampling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/randomized/ReservoirSampling.java)
           * recursion
             * [FibonacciSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java)
             * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/recursion/GenerateSubsets.java)
@@ -618,6 +628,8 @@
             * [LongestSubstringWithoutRepeatingCharacters](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java)
             * [MaxSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java)
             * [MinSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java)
+            * [ShortestCoprimeSegment](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegment.java)
+
           * sorts
             * [AdaptiveMergeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java)
             * [BeadSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BeadSort.java)
@@ -941,6 +953,7 @@
               * [BSTFromSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTFromSortedArrayTest.java)
               * [BSTIterativeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTIterativeTest.java)
               * [BSTRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveTest.java)
+              * [BTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BTreeTest.java)
               * [CeilInBinarySearchTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTreeTest.java)
               * [CheckBinaryTreeIsValidBSTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBSTTest.java)
               * [CheckIfBinaryTreeBalancedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalancedTest.java)
@@ -990,6 +1003,7 @@
             * [LongestAlternatingSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java)
             * [LongestArithmeticSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequenceTest.java)
             * [LongestCommonSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java)
+            * [LongestIncreasingSubsequenceNLogNTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogNTest.java)
             * [LongestIncreasingSubsequenceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java)
             * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java)
             * [LongestValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java)
@@ -1023,7 +1037,9 @@
             * [MidpointEllipseTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java)
           * graph
             * [ConstrainedShortestPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java)
-            * [StronglyConnectedComponentOptimizedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)
+            * [StronglyConnectedComponentOptimizedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/
+            * [TravelingSalesmanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java)
+StronglyConnectedComponentOptimizedTest.java)
           * greedyalgorithms
             * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
             * [BandwidthAllocationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java)
@@ -1159,6 +1175,7 @@
             * [MatrixUtilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MatrixUtilTest.java)
             * [MedianOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java)
             * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java)
+            * [SolveSystemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/SolveSystemTest.java)
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java)
           * misc
             * [ColorContrastRatioTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java)
@@ -1205,6 +1222,11 @@
             * [SudokuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java)
             * [TowerOfHanoiTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java)
             * [WordBoggleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/puzzlesandgames/WordBoggleTest.java)
+          * randomize
+            * [KargerMinCutTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/randomized/KargerMinCutTest.java)
+            * [MonteCarloIntegrationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/randomized/MonteCarloIntegrationTest.java)
+            * [RandomizedQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/randomized/RandomizedQuickSortTest.java)
+            * [ReservoirSamplingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/randomized/ReservoirSamplingTest.java)
           * recursion
             * [FibonacciSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/recursion/FibonacciSeriesTest.java)
             * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java)
@@ -1272,6 +1294,7 @@
             * [LongestSubstringWithoutRepeatingCharactersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java)
             * [MaxSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java)
             * [MinSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java)
+            * [ShortestCoprimeSegmentTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegmentTest.java)
           * sorts
             * [AdaptiveMergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java)
             * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
@@ -1349,6 +1372,7 @@
             * [AlphabeticalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java)
             * [AnagramsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AnagramsTest.java)
             * [CharacterSameTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CharacterSameTest.java)
+            * [CharactersSameTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CharactersSameTest.java)
             * [CheckAnagramsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CheckAnagramsTest.java)
             * [CheckVowelsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java)
             * [CountCharTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CountCharTest.java)

From 83bc063a39dd1c0561ec0d9bf254a2e4f150502f Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 25 Jun 2025 20:37:06 +0200
Subject: [PATCH 0820/1338] chore: perform CodeQL scan on actions (#6309)

---
 .github/workflows/codeql.yml | 33 ++++++++++++++++++++++++++-------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index a0908a2b57d9..d1133c251b65 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -10,12 +10,9 @@ on:
   schedule:
     - cron: '53 3 * * 0'
 
-env:
-  LANGUAGE: 'java-kotlin'
-
 jobs:
-  analyze:
-    name: Analyze
+  analyzeJava:
+    name: AnalyzeJava
     runs-on: 'ubuntu-latest'
     permissions:
       actions: read
@@ -35,7 +32,7 @@ jobs:
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v3
         with:
-          languages: ${{ env.LANGUAGE }}
+          languages: 'java-kotlin'
 
       - name: Build
         run: mvn --batch-mode --update-snapshots verify
@@ -43,5 +40,27 @@ jobs:
       - name: Perform CodeQL Analysis
         uses: github/codeql-action/analyze@v3
         with:
-          category: "/language:${{env.LANGUAGE}}"
+          category: "/language:java-kotlin"
+
+  analyzeActions:
+    name: AnalyzeActions
+    runs-on: 'ubuntu-latest'
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: 'actions'
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v3
+        with:
+          category: "/language:actions"
 ...

From bb71ae2121cd8a88bfc9119975e5ee9a619edad2 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 25 Jun 2025 18:40:36 +0000
Subject: [PATCH 0821/1338] chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.3.0 to 4.9.3.1 (#6313)

chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.3.0 to 4.9.3.1.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.3.0...spotbugs-maven-plugin-4.9.3.1)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.3.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 37a8940000c9..255290e21e40 100644
--- a/pom.xml
+++ b/pom.xml
@@ -120,7 +120,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.3.0</version>
+                <version>4.9.3.1</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From a91ad201df14c7c75011450cbc737ae4585b930e Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 25 Jun 2025 18:43:39 +0000
Subject: [PATCH 0822/1338] chore(deps): bump org.junit:junit-bom from 5.13.1
 to 5.13.2 (#6314)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 5.13.1 to 5.13.2.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r5.13.1...r5.13.2)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 5.13.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 255290e21e40..2619d4d50f28 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.13.1</version>
+                <version>5.13.2</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 428d259f7c2f08c7f6687fb16f08fcfae8f1c6f7 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 25 Jun 2025 18:46:54 +0000
Subject: [PATCH 0823/1338] chore(deps): bump gitpod/workspace-java-21 from
 2025-05-14-07-50-25 to 2025-06-18-16-47-14 (#6312)

chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2025-05-14-07-50-25 to 2025-06-18-16-47-14.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-version: 2025-06-18-16-47-14
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 69fee306e1e4..b912ecb35256 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2025-05-14-07-50-25
+FROM gitpod/workspace-java-21:2025-06-18-16-47-14
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 5529cb2ca41788f769e38c7c7dcfa2a3e4bb6bcb Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 25 Jun 2025 22:30:04 +0200
Subject: [PATCH 0824/1338] chore: explicitly set permissions (#6316)

---
 .github/workflows/build.yml             | 3 +++
 .github/workflows/clang-format-lint.yml | 3 +++
 .github/workflows/infer.yml             | 3 +++
 .github/workflows/project_structure.yml | 3 +++
 .github/workflows/stale.yml             | 5 +++++
 5 files changed, 17 insertions(+)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b3969075d668..3918e89533d5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -1,6 +1,9 @@
 name: Build
 on: [push, pull_request]
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/clang-format-lint.yml b/.github/workflows/clang-format-lint.yml
index dac697511de1..6f23946db999 100644
--- a/.github/workflows/clang-format-lint.yml
+++ b/.github/workflows/clang-format-lint.yml
@@ -3,6 +3,9 @@ on:
   push: {}
   pull_request: {}
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index ffadd13ff3bd..b0ee2fee8243 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -8,6 +8,9 @@ name: Infer
       - master
   pull_request:
 
+permissions:
+  contents: read
+
 jobs:
   run_infer:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/project_structure.yml b/.github/workflows/project_structure.yml
index def01554a4f8..dbc725655721 100644
--- a/.github/workflows/project_structure.yml
+++ b/.github/workflows/project_structure.yml
@@ -8,6 +8,9 @@ name: ProjectStructure
       - master
   pull_request:
 
+permissions:
+  contents: read
+
 jobs:
   check_structure:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index 6fb47c5d2dc9..186b3e1d2f5a 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -2,8 +2,13 @@ name: 'Close stale issues and PRs'
 on:
   schedule:
     - cron: '0 0 * * *'
+permissions:
+  contents: read
 jobs:
   stale:
+    permissions:
+      issues: write
+      pull-requests: write
     runs-on: ubuntu-latest
     steps:
       - uses: actions/stale@v9

From ba0b0c4176747b8f68bb9ef51287e79d3babbfc3 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 25 Jun 2025 20:33:03 +0000
Subject: [PATCH 0825/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 10.25.0 to 10.26.0 (#6315)

chore(deps): bump com.puppycrawl.tools:checkstyle

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.25.0 to 10.26.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.25.0...checkstyle-10.26.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 10.26.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 2619d4d50f28..afb6ff43ed99 100644
--- a/pom.xml
+++ b/pom.xml
@@ -113,7 +113,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.25.0</version>
+                    <version>10.26.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From a8ad1625170273ee36e82f38d84590b5e3bc8248 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 26 Jun 2025 00:47:39 +0300
Subject: [PATCH 0826/1338] chore(deps): bump
 org.apache.maven.plugins:maven-pmd-plugin from 3.26.0 to 3.27.0 (#6317)

chore(deps): bump org.apache.maven.plugins:maven-pmd-plugin

Bumps [org.apache.maven.plugins:maven-pmd-plugin](https://github.com/apache/maven-pmd-plugin) from 3.26.0 to 3.27.0.
- [Release notes](https://github.com/apache/maven-pmd-plugin/releases)
- [Commits](https://github.com/apache/maven-pmd-plugin/compare/maven-pmd-plugin-3.26.0...maven-pmd-plugin-3.27.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-pmd-plugin
  dependency-version: 3.27.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index afb6ff43ed99..1978d12901df 100644
--- a/pom.xml
+++ b/pom.xml
@@ -141,7 +141,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-pmd-plugin</artifactId>
-                <version>3.26.0</version>
+                <version>3.27.0</version>
                 <configuration>
                     <rulesets>
                         <ruleset>/rulesets/java/maven-pmd-plugin-default.xml</ruleset>

From 981d73d02cf3a2caf31d91fd5c393023fb501964 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 28 Jun 2025 16:18:32 +0300
Subject: [PATCH 0827/1338] chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.3.1 to 4.9.3.2 (#6319)

chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.3.1 to 4.9.3.2.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.3.1...spotbugs-maven-plugin-4.9.3.2)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.3.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 1978d12901df..0b638c1fc709 100644
--- a/pom.xml
+++ b/pom.xml
@@ -120,7 +120,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.3.1</version>
+                <version>4.9.3.2</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 67ccb6246559948485864f287b26937da952e0bf Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Sun, 29 Jun 2025 09:05:51 +0200
Subject: [PATCH 0828/1338] Modernize GitHub Action to auto-generate
 DIRECTORY.md (#6308)

---
 .github/workflows/update-directorymd.yml | 33 +++++++++
 .github/workflows/update_directory.yml   | 92 ------------------------
 2 files changed, 33 insertions(+), 92 deletions(-)
 create mode 100644 .github/workflows/update-directorymd.yml
 delete mode 100644 .github/workflows/update_directory.yml

diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
new file mode 100644
index 000000000000..59b0565f1177
--- /dev/null
+++ b/.github/workflows/update-directorymd.yml
@@ -0,0 +1,33 @@
+name: Generate Directory Markdown
+
+on:
+  push:
+    branches: [master]
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  generate-directory:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v4
+
+      - name: Run Directory Tree Generator
+        uses: DenizAltunkapan/directory-tree-generator@v2
+        with:
+          path: src
+          extensions: .java
+          show-extensions: false
+
+      - name: Commit and Push DIRECTORY.md
+        run: |
+          cat DIRECTORY.md
+          git config --global user.name "$GITHUB_ACTOR"
+          git config --global user.email "$GITHUB_ACTOR@users.noreply.github.com"
+          git remote set-url origin https://x-access-token:${{ secrets.GITHUB_TOKEN }}@github.com/$GITHUB_REPOSITORY
+          git add DIRECTORY.md
+          git commit -am "Update directory" || true
+          git push origin HEAD:$GITHUB_REF
diff --git a/.github/workflows/update_directory.yml b/.github/workflows/update_directory.yml
deleted file mode 100644
index c811d244e54b..000000000000
--- a/.github/workflows/update_directory.yml
+++ /dev/null
@@ -1,92 +0,0 @@
-# This GitHub Action updates the DIRECTORY.md file (if needed) when doing a git push or pull_request
-name: Update Directory
-permissions:
-  contents: write
-on:
-  push:
-    paths:
-      - 'src/**'
-  pull_request:
-    paths:
-      - 'src/**'
-  workflow_dispatch:
-    inputs:
-      logLevel:
-        description: 'Log level'
-        required: true
-        default: 'info'
-        type: choice
-        options:
-          - info
-          - warning
-          - debug
-jobs:
-  update_directory_md:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@master
-      - uses: actions/setup-python@v5
-        with:
-          python-version: '3.x'
-      - name: Update Directory
-        shell: python
-        run: |
-            import os
-            from typing import Iterator
-
-            URL_BASE = "https://github.com/TheAlgorithms/Java/blob/master"
-            g_output = []
-
-
-            def good_filepaths(top_dir: str = ".") -> Iterator[str]:
-                for dirpath, dirnames, filenames in os.walk(top_dir):
-                    dirnames[:] = [d for d in dirnames if d[0] not in "._"]
-                    for filename in filenames:
-                        if os.path.splitext(filename)[1].lower() == ".java":
-                            yield os.path.join(dirpath, filename).lstrip("./")
-
-
-            def md_prefix(i):
-                return f"{i * '  '}*" if i else "\n##"
-
-
-            def print_path(old_path: str, new_path: str) -> str:
-                global g_output
-                old_parts = old_path.split(os.sep)
-                mid_diff = False
-                new_parts = new_path.split(os.sep)
-                for i, new_part in enumerate(new_parts):
-                    if i + 1 > len(old_parts) or old_parts[i] != new_part or mid_diff:
-                        if i + 1 < len(new_parts):
-                            mid_diff = True
-                        if new_part:
-                            g_output.append(f"{md_prefix(i)} {new_part.replace('_', ' ')}")
-                return new_path
-
-
-            def build_directory_md(top_dir: str = ".") -> str:
-                global g_output
-                old_path = ""
-                for filepath in sorted(good_filepaths(top_dir), key=str.lower):
-                    filepath, filename = os.path.split(filepath)
-                    if filepath != old_path:
-                        old_path = print_path(old_path, filepath)
-                    indent = (filepath.count(os.sep) + 1) if filepath else 0
-                    url = "/".join((URL_BASE, filepath, filename)).replace(" ", "%20")
-                    filename = os.path.splitext(filename.replace("_", " "))[0]
-                    g_output.append(f"{md_prefix(indent)} [{filename}]({url})")
-                return "\n".join(g_output)
-
-
-            with open("DIRECTORY.md", "w") as out_file:
-                out_file.write(build_directory_md(".") + "\n")
-
-      - name: Update DIRECTORY.md
-        run: |
-          cat DIRECTORY.md
-          git config --global user.name "$GITHUB_ACTOR"
-          git config --global user.email "$GITHUB_ACTOR@users.noreply.github.com"
-          git remote set-url origin https://x-access-token:${{ secrets.GITHUB_TOKEN }}@github.com/$GITHUB_REPOSITORY
-          git add DIRECTORY.md
-          git commit -am "Update directory" ||  true
-          git push --force origin HEAD:$GITHUB_REF || true

From d14873f172440d909926c11b3df3f7a9040aa230 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Sun, 29 Jun 2025 11:16:02 +0200
Subject: [PATCH 0829/1338] Automatically create pull requests for directory
 updates (#6322)

---
 .github/workflows/update-directorymd.yml | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index 59b0565f1177..f558cec4fc08 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -1,4 +1,4 @@
-name: Generate Directory Markdown
+name: Generate Directory Markdown
 
 on:
   push:
@@ -7,6 +7,7 @@ on:
 
 permissions:
   contents: write
+  pull-requests: write
 
 jobs:
   generate-directory:
@@ -22,12 +23,19 @@ jobs:
           extensions: .java
           show-extensions: false
 
-      - name: Commit and Push DIRECTORY.md
+      - name: Commit changes
         run: |
-          cat DIRECTORY.md
           git config --global user.name "$GITHUB_ACTOR"
           git config --global user.email "$GITHUB_ACTOR@users.noreply.github.com"
-          git remote set-url origin https://x-access-token:${{ secrets.GITHUB_TOKEN }}@github.com/$GITHUB_REPOSITORY
           git add DIRECTORY.md
-          git commit -am "Update directory" || true
-          git push origin HEAD:$GITHUB_REF
+          git diff --cached --quiet || git commit -m "Update DIRECTORY.md"
+      
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v5
+        with:
+          branch: update-directory
+          base: master
+          title: "Update DIRECTORY.md"
+          body: "Automatically generated update of the directory tree."
+          commit-message: "Update DIRECTORY.md"
+          draft: false

From e43a1f75e60b97cc4f620e6b3452058812e9845c Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Sun, 29 Jun 2025 13:20:37 +0200
Subject: [PATCH 0830/1338] Update update-directorymd.yml using PAT (#6324)

Update update-directorymd.yml
---
 .github/workflows/update-directorymd.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index f558cec4fc08..39269c43d67f 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -32,6 +32,8 @@ jobs:
       
       - name: Create Pull Request
         uses: peter-evans/create-pull-request@v5
+        env:
+          GITHUB_TOKEN: ${{ secrets.REPO_SCOPED_TOKEN }}
         with:
           branch: update-directory
           base: master

From d06fe8b012cfc1a8338b03b9fe5bbfa1ec189fd8 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Sun, 29 Jun 2025 14:47:07 +0200
Subject: [PATCH 0831/1338] Update update-directorymd.yml (#6326)

---
 .github/workflows/update-directorymd.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index 39269c43d67f..4615ef27f830 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -8,6 +8,7 @@ on:
 permissions:
   contents: write
   pull-requests: write
+  workflows: write
 
 jobs:
   generate-directory:
@@ -32,9 +33,8 @@ jobs:
       
       - name: Create Pull Request
         uses: peter-evans/create-pull-request@v5
-        env:
-          GITHUB_TOKEN: ${{ secrets.REPO_SCOPED_TOKEN }}
         with:
+          token: ${{ secrets.REPO_SCOPED_TOKEN }}
           branch: update-directory
           base: master
           title: "Update DIRECTORY.md"

From 617412efc021ce7fe3f9653d90416057bcb2c16e Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Sun, 29 Jun 2025 14:57:07 +0200
Subject: [PATCH 0832/1338] delete workflows from update-directorymd.yml
 (#6327)

---
 .github/workflows/update-directorymd.yml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index 4615ef27f830..6bc6485f61fb 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -8,7 +8,6 @@ on:
 permissions:
   contents: write
   pull-requests: write
-  workflows: write
 
 jobs:
   generate-directory:

From 9abf4e38de1b8cf640c9b52600b8b5af7236c7ce Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Mon, 30 Jun 2025 07:17:33 +0200
Subject: [PATCH 0833/1338] Update DIRECTORY.md (#6328)

Co-authored-by: DenizAltunkapan <DenizAltunkapan@users.noreply.github.com>
---
 DIRECTORY.md | 2815 +++++++++++++++++++++++++-------------------------
 1 file changed, 1410 insertions(+), 1405 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 5cc12315d10b..7a4c25afe9ca 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1,1406 +1,1411 @@
+# Project Structure
 
-## src
-  * main
-    * java
-      * com
-        * thealgorithms
-          * audiofilters
-            * [EMAFilter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/audiofilters/EMAFilter.java)
-            * [IIRFilter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/audiofilters/IIRFilter.java)
-          * backtracking
-            * [AllPathsFromSourceToTarget](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java)
-            * [ArrayCombination](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java)
-            * [Combination](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/Combination.java)
-            * [CrosswordSolver](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java)
-            * [FloodFill](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/FloodFill.java)
-            * [KnightsTour](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/KnightsTour.java)
-            * [MazeRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/MazeRecursion.java)
-            * [MColoring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/MColoring.java)
-            * [NQueens](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/NQueens.java)
-            * [ParenthesesGenerator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java)
-            * [Permutation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/Permutation.java)
-            * [PowerSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/PowerSum.java)
-            * [SubsequenceFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/SubsequenceFinder.java)
-            * [WordPatternMatcher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordPatternMatcher.java)
-            * [WordSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/backtracking/WordSearch.java)
-          * bitmanipulation
-            * [BcdConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java)
-            * [BinaryPalindromeCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java)
-            * [BitSwap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
-            * [BooleanAlgebraGates](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGates.java)
-            * [ClearLeftmostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java)
-            * [CountLeadingZeros](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java)
-            * [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
-            * [FindNthBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/FindNthBit.java)
-            * [FirstDifferentBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/FirstDifferentBit.java)
-            * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GenerateSubsets.java)
-            * [GrayCodeConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java)
-            * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java)
-            * [HigherLowerPowerOfTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java)
-            * [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
-            * [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
-            * [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
-            * [IsPowerTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java)
-            * [LowestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/LowestSetBit.java)
-            * [ModuloPowerOfTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwo.java)
-            * [NextHigherSameBitCount](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCount.java)
-            * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
-            * [NumberAppearingOddTimes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java)
-            * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
-            * [OneBitDifference](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/OneBitDifference.java)
-            * [OnesComplement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java)
-            * [ParityCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ParityCheck.java)
-            * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
-            * [SingleBitOperations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java)
-            * [SingleElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleElement.java)
-            * [SwapAdjacentBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java)
-            * [TwosComplement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java)
-            * [Xs3Conversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/Xs3Conversion.java)
-          * ciphers
-            * a5
-              * [A5Cipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/A5Cipher.java)
-              * [A5KeyStreamGenerator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/A5KeyStreamGenerator.java)
-              * [BaseLFSR](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/BaseLFSR.java)
-              * [CompositeLFSR](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java)
-              * [LFSR](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/LFSR.java)
-              * [Utils](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/a5/Utils.java)
-            * [ADFGVXCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java)
-            * [AES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AES.java)
-            * [AESEncryption](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AESEncryption.java)
-            * [AffineCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AffineCipher.java)
-            * [AtbashCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/AtbashCipher.java)
-            * [Autokey](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Autokey.java)
-            * [BaconianCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/BaconianCipher.java)
-            * [Blowfish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Blowfish.java)
-            * [Caesar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Caesar.java)
-            * [ColumnarTranspositionCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java)
-            * [DES](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/DES.java)
-            * [DiffieHellman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/DiffieHellman.java)
-            * [ECC](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ECC.java)
-            * [HillCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/HillCipher.java)
-            * [MonoAlphabetic](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/MonoAlphabetic.java)
-            * [PlayfairCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java)
-            * [Polybius](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Polybius.java)
-            * [ProductCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/ProductCipher.java)
-            * [RailFenceCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java)
-            * [RSA](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/RSA.java)
-            * [SimpleSubCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/SimpleSubCipher.java)
-            * [Vigenere](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/Vigenere.java)
-            * [XORCipher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/ciphers/XORCipher.java)
-          * conversions
-            * [AffineConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AffineConverter.java)
-            * [AnyBaseToAnyBase](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java)
-            * [AnyBaseToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java)
-            * [AnytoAny](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/AnytoAny.java)
-            * [BinaryToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java)
-            * [BinaryToHexadecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java)
-            * [BinaryToOctal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/BinaryToOctal.java)
-            * [DecimalToAnyBase](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java)
-            * [DecimalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToBinary.java)
-            * [DecimalToHexadecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToHexadecimal.java)
-            * [DecimalToOctal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/DecimalToOctal.java)
-            * [EndianConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/EndianConverter.java)
-            * [HexaDecimalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java)
-            * [HexaDecimalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java)
-            * [HexToOct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexToOct.java)
-            * [IntegerToEnglish](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java)
-            * [IntegerToRoman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java)
-            * [IPConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IPConverter.java)
-            * [IPv6Converter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IPv6Converter.java)
-            * [MorseCodeConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/MorseCodeConverter.java)
-            * [NumberToWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/NumberToWords.java)
-            * [OctalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToBinary.java)
-            * [OctalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java)
-            * [OctalToHexadecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java)
-            * [PhoneticAlphabetConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java)
-            * [RgbHsvConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java)
-            * [RomanToInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/RomanToInteger.java)
-            * [TurkishToLatinConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java)
-            * [UnitConversions](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/UnitConversions.java)
-            * [UnitsConverter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/UnitsConverter.java)
-            * [WordsToNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/WordsToNumber.java)
-          * datastructures
-            * bags
-              * [Bag](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/bags/Bag.java)
-            * bloomfilter
-              * [BloomFilter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java)
-            * buffers
-              * [CircularBuffer](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java)
-            * caches
-              * [LFUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java)
-              * [LRUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java)
-              * [MRUCache](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java)
-            * crdt
-              * [GCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java)
-              * [GSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/GSet.java)
-              * [LWWElementSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java)
-              * [ORSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/ORSet.java)
-              * [PNCounter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java)
-              * [TwoPSet](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java)
-            * disjointsetunion
-              * [DisjointSetUnion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java)
-              * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/disjointsetunion/Node.java)
-            * dynamicarray
-              * [DynamicArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java)
-            * graphs
-              * [AStar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/AStar.java)
-              * [BellmanFord](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java)
-              * [BipartiteGraphDFS](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java)
-              * [BoruvkaAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithm.java)
-              * [ConnectedComponent](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java)
-              * [Cycles](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java)
-              * [DijkstraAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java)
-              * [DijkstraOptimizedAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java)
-              * [EdmondsBlossomAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java)
-              * [FloydWarshall](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java)
-              * [FordFulkerson](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java)
-              * [Graphs](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java)
-              * [HamiltonianCycle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java)
-              * [JohnsonsAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java)
-              * [KahnsAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java)
-              * [Kosaraju](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java)
-              * [Kruskal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java)
-              * [MatrixGraphs](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java)
-              * [PrimMST](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java)
-              * [TarjansAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java)
-              * [UndirectedAdjacencyListGraph](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/UndirectedAdjacencyListGraph.java)
-              * [WelshPowell](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java)
-            * hashmap
-              * hashing
-                * [GenericHashMapUsingArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java)
-                * [GenericHashMapUsingArrayList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java)
-                * [HashMap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java)
-                * [HashMapCuckooHashing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java)
-                * [Intersection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java)
-                * [LinearProbingHashMap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java)
-                * [MainCuckooHashing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java)
-                * [MajorityElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java)
-                * [Map](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Map.java)
-            * heaps
-              * [EmptyHeapException](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/EmptyHeapException.java)
-              * [FibonacciHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java)
-              * [GenericHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java)
-              * [Heap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/Heap.java)
-              * [HeapElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java)
-              * [KthElementFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/KthElementFinder.java)
-              * [LeftistHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java)
-              * [MaxHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java)
-              * [MedianFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MedianFinder.java)
-              * [MergeKSortedArrays](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MergeKSortedArrays.java)
-              * [MinHeap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java)
-              * [MinPriorityQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java)
-            * lists
-              * [CircleLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java)
-              * [CountSinglyLinkedListRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java)
-              * [CreateAndDetectLoop](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java)
-              * [CursorLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java)
-              * [DoublyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java)
-              * [MergeKSortedLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java)
-              * [MergeSortedArrayList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java)
-              * [MergeSortedSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java)
-              * [QuickSortLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java)
-              * [RandomNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/RandomNode.java)
-              * [ReverseKGroup](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java)
-              * [RotateSinglyLinkedLists](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java)
-              * [SearchSinglyLinkedListRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java)
-              * [SinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java)
-              * [SinglyLinkedListNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedListNode.java)
-              * [SkipList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java)
-              * [SortedLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java)
-            * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/Node.java)
-            * queues
-              * [CircularQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java)
-              * [Deque](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/Deque.java)
-              * [GenericArrayListQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java)
-              * [LinkedQueue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java)
-              * [PriorityQueues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java)
-              * [Queue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/Queue.java)
-              * [QueueByTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java)
-              * [SlidingWindowMaximum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximum.java)
-              * [TokenBucket](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/queues/TokenBucket.java)
-            * stacks
-              * [NodeStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java)
-              * [ReverseStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java)
-              * [Stack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/Stack.java)
-              * [StackArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java)
-              * [StackArrayList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java)
-              * [StackOfLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java)
-            * trees
-              * [AVLSimple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java)
-              * [AVLTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java)
-              * [BinaryTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java)
-              * [BoundaryTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BoundaryTraversal.java)
-              * [BSTFromSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTFromSortedArray.java)
-              * [BSTIterative](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTIterative.java)
-              * [BSTRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursive.java)
-              * [BSTRecursiveGeneric](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java)
-              * [BTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/BTree.java)
-              * [CeilInBinarySearchTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java)
-              * [CheckBinaryTreeIsValidBST](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBST.java)
-              * [CheckIfBinaryTreeBalanced](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalanced.java)
-              * [CheckTreeIsSymmetric](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetric.java)
-              * [CreateBinaryTreeFromInorderPreorder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorder.java)
-              * [FenwickTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java)
-              * [GenericTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java)
-              * [InorderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java)
-              * [KDTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/KDTree.java)
-              * [LazySegmentTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java)
-              * [LCA](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/LCA.java)
-              * [LevelOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/LevelOrderTraversal.java)
-              * [nearestRightKey](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java)
-              * [PostOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java)
-              * [PreOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java)
-              * [PrintTopViewofTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java)
-              * [QuadTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/QuadTree.java)
-              * [RedBlackBST](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java)
-              * [SameTreesCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java)
-              * [SegmentTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java)
-              * [SplayTree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/SplayTree.java)
-              * [Treap](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/Treap.java)
-              * [TreeRandomNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java)
-              * [Trie](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/Trie.java)
-              * [VerticalOrderTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java)
-              * [ZigzagTraversal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java)
-          * devutils
-            * entities
-              * [ProcessDetails](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/devutils/entities/ProcessDetails.java)
-            * nodes
-              * [LargeTreeNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/devutils/nodes/LargeTreeNode.java)
-              * [Node](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/devutils/nodes/Node.java)
-              * [SimpleNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/devutils/nodes/SimpleNode.java)
-              * [SimpleTreeNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/devutils/nodes/SimpleTreeNode.java)
-              * [TreeNode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/devutils/nodes/TreeNode.java)
-            * searches
-              * [MatrixSearchAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/devutils/searches/MatrixSearchAlgorithm.java)
-              * [SearchAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/devutils/searches/SearchAlgorithm.java)
-          * divideandconquer
-            * [BinaryExponentiation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java)
-            * [ClosestPair](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java)
-            * [CountingInversions](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/CountingInversions.java)
-            * [MedianOfTwoSortedArrays](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArrays.java)
-            * [SkylineAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java)
-            * [StrassenMatrixMultiplication](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplication.java)
-            * [TilingProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/divideandconquer/TilingProblem.java)
-          * dynamicprogramming
-            * [Abbreviation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Abbreviation.java)
-            * [AllConstruct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/AllConstruct.java)
-            * [AssignmentUsingBitmask](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmask.java)
-            * [BoardPath](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java)
-            * [BoundaryFill](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java)
-            * [BruteForceKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java)
-            * [CatalanNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java)
-            * [ClimbingStairs](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java)
-            * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java)
-            * [CountFriendsPairing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java)
-            * [DiceThrow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java)
-            * [EditDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java)
-            * [EggDropping](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java)
-            * [Fibonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java)
-            * [KadaneAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java)
-            * [Knapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java)
-            * [KnapsackMemoization](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java)
-            * [LevenshteinDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java)
-            * [LongestAlternatingSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java)
-            * [LongestArithmeticSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java)
-            * [LongestCommonSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java)
-            * [LongestIncreasingSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java)
-            * [LongestIncreasingSubsequenceNLogN](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogN.java)
-            * [LongestPalindromicSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java)
-            * [LongestPalindromicSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java)
-            * [LongestValidParentheses](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/LongestValidParentheses.java)
-            * [MatrixChainMultiplication](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java)
-            * [MatrixChainRecursiveTopDownMemoisation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java)
-            * [MaximumSumOfNonAdjacentElements](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElements.java)
-            * [MinimumPathSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/MinimumPathSum.java)
-            * [MinimumSumPartition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/MinimumSumPartition.java)
-            * [NewManShanksPrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java)
-            * [OptimalJobScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java)
-            * [PalindromicPartitioning](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java)
-            * [PartitionProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java)
-            * [RegexMatching](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java)
-            * [RodCutting](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java)
-            * [ShortestCommonSupersequenceLength](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java)
-            * [SubsetCount](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java)
-            * [SubsetSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java)
-            * [SubsetSumSpaceOptimized](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java)
-            * [SumOfSubset](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java)
-            * [TreeMatching](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/TreeMatching.java)
-            * [Tribonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java)
-            * [UniquePaths](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java)
-            * [UniqueSubsequencesCount](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCount.java)
-            * [WildcardMatching](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java)
-            * [WineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java)
-          * geometry
-            * [BresenhamLine](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/BresenhamLine.java)
-            * [ConvexHull](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/ConvexHull.java)
-            * [GrahamScan](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/GrahamScan.java)
-            * [MidpointCircle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/MidpointCircle.java)
-            * [MidpointEllipse](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/MidpointEllipse.java)
-            * [Point](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/Point.java)
-          * graph
-            * [ConstrainedShortestPath](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java)
-            * [StronglyConnectedComponentOptimized](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
-            * [TravelingSalesman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/TravelingSalesman.java)
-          * greedyalgorithms
-            * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
-            * [BandwidthAllocation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java)
-            * [BinaryAddition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java)
-            * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java)
-            * [DigitSeparation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java)
-            * [EgyptianFraction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/EgyptianFraction.java)
-            * [FractionalKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
-            * [GaleShapley](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java)
-            * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
-            * [KCenters](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/KCenters.java)
-            * [MergeIntervals](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java)
-            * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java)
-            * [MinimumWaitingTime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTime.java)
-            * [OptimalFileMerging](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java)
-            * [StockProfitCalculator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java)
-          * io
-            * [BufferedReader](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/io/BufferedReader.java)
-          * lineclipping
-            * [CohenSutherland](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/lineclipping/CohenSutherland.java)
-            * [LiangBarsky](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/lineclipping/LiangBarsky.java)
-            * utils
-              * [Line](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/lineclipping/utils/Line.java)
-              * [Point](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/lineclipping/utils/Point.java)
-          * maths
-            * [AbsoluteMax](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AbsoluteMax.java)
-            * [AbsoluteMin](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AbsoluteMin.java)
-            * [AbsoluteValue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AbsoluteValue.java)
-            * [ADTFraction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ADTFraction.java)
-            * [AliquotSum](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AliquotSum.java)
-            * [AmicableNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AmicableNumber.java)
-            * [Area](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Area.java)
-            * [Armstrong](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Armstrong.java)
-            * [AutoCorrelation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AutoCorrelation.java)
-            * [AutomorphicNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java)
-            * [Average](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Average.java)
-            * [BinaryPow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinaryPow.java)
-            * [BinomialCoefficient](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java)
-            * [CatalanNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CatalanNumbers.java)
-            * [Ceil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Ceil.java)
-            * [ChineseRemainderTheorem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java)
-            * [CircularConvolutionFFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java)
-            * [CollatzConjecture](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CollatzConjecture.java)
-            * [Combinations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Combinations.java)
-            * [Convolution](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Convolution.java)
-            * [ConvolutionFFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java)
-            * [CrossCorrelation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CrossCorrelation.java)
-            * [DeterminantOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java)
-            * [DigitalRoot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DigitalRoot.java)
-            * [DistanceFormula](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DistanceFormula.java)
-            * [DudeneyNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DudeneyNumber.java)
-            * [EulerMethod](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/EulerMethod.java)
-            * [EulersFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/EulersFunction.java)
-            * [Factorial](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Factorial.java)
-            * [FactorialRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FactorialRecursion.java)
-            * [FastExponentiation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FastExponentiation.java)
-            * [FastInverseSqrt](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FastInverseSqrt.java)
-            * [FFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FFT.java)
-            * [FFTBluestein](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FFTBluestein.java)
-            * [FibonacciJavaStreams](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java)
-            * [FibonacciLoop](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FibonacciLoop.java)
-            * [FibonacciNumberCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java)
-            * [FibonacciNumberGoldenRation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java)
-            * [FindKthNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FindKthNumber.java)
-            * [FindMax](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FindMax.java)
-            * [FindMaxRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FindMaxRecursion.java)
-            * [FindMin](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FindMin.java)
-            * [FindMinRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FindMinRecursion.java)
-            * [Floor](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Floor.java)
-            * [FrizzyNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/FrizzyNumber.java)
-            * [Gaussian](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Gaussian.java)
-            * [GCD](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/GCD.java)
-            * [GCDRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/GCDRecursion.java)
-            * [GenericRoot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/GenericRoot.java)
-            * [GoldbachConjecture](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/GoldbachConjecture.java)
-            * [HarshadNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/HarshadNumber.java)
-            * [HeronsFormula](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/HeronsFormula.java)
-            * [JosephusProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/JosephusProblem.java)
-            * [JugglerSequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/JugglerSequence.java)
-            * [KaprekarNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java)
-            * [KaratsubaMultiplication](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KaratsubaMultiplication.java)
-            * [KeithNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KeithNumber.java)
-            * [KrishnamurthyNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java)
-            * [LeastCommonMultiple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java)
-            * [LeonardoNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LeonardoNumber.java)
-            * [LinearDiophantineEquationsSolver](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java)
-            * [LongDivision](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LongDivision.java)
-            * [LucasSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LucasSeries.java)
-            * [MagicSquare](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MagicSquare.java)
-            * [MathBuilder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MathBuilder.java)
-            * [MaxValue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MaxValue.java)
-            * [Means](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Means.java)
-            * [Median](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Median.java)
-            * [MinValue](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/MinValue.java)
-            * [Mode](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Mode.java)
-            * [NonRepeatingElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/NonRepeatingElement.java)
-            * [NthUglyNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/NthUglyNumber.java)
-            * [NumberOfDigits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/NumberOfDigits.java)
-            * [PalindromeNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PalindromeNumber.java)
-            * [ParseInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ParseInteger.java)
-            * [PascalTriangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PascalTriangle.java)
-            * [PerfectCube](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PerfectCube.java)
-            * [PerfectNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PerfectNumber.java)
-            * [PerfectSquare](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PerfectSquare.java)
-            * [Perimeter](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Perimeter.java)
-            * [PiNilakantha](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PiNilakantha.java)
-            * [PollardRho](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PollardRho.java)
-            * [Pow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Pow.java)
-            * [PowerOfTwoOrNot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PowerOfTwoOrNot.java)
-            * [PowerUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PowerUsingRecursion.java)
-            * Prime
-              * [LiouvilleLambdaFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/LiouvilleLambdaFunction.java)
-              * [MillerRabinPrimalityCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/MillerRabinPrimalityCheck.java)
-              * [MobiusFunction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/MobiusFunction.java)
-              * [PrimeCheck](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/PrimeCheck.java)
-              * [PrimeFactorization](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/PrimeFactorization.java)
-              * [SquareFreeInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Prime/SquareFreeInteger.java)
-            * [PronicNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PronicNumber.java)
-            * [PythagoreanTriple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java)
-            * [QuadraticEquationSolver](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/QuadraticEquationSolver.java)
-            * [ReverseNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ReverseNumber.java)
-            * [RomanNumeralUtil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/RomanNumeralUtil.java)
-            * [SecondMinMax](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SecondMinMax.java)
-            * [SieveOfEratosthenes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java)
-            * [SimpsonIntegration](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SimpsonIntegration.java)
-            * [SolovayStrassenPrimalityTest](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java)
-            * [SquareRootWithBabylonianMethod](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java)
-            * [SquareRootWithNewtonRaphsonMethod](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonMethod.java)
-            * [StandardDeviation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/StandardDeviation.java)
-            * [StandardScore](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/StandardScore.java)
-            * [StrobogrammaticNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/StrobogrammaticNumber.java)
-            * [SumOfArithmeticSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SumOfArithmeticSeries.java)
-            * [SumOfDigits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SumOfDigits.java)
-            * [SumOfOddNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java)
-            * [SumWithoutArithmeticOperators](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SumWithoutArithmeticOperators.java)
-            * [TrinomialTriangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java)
-            * [TwinPrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/TwinPrime.java)
-            * [UniformNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/UniformNumbers.java)
-            * [VampireNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/VampireNumber.java)
-            * [VectorCrossProduct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java)
-            * [Volume](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Volume.java)
-          * matrix
-            * [InverseOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/InverseOfMatrix.java)
-            * matrixexponentiation
-              * [Fibonacci](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java)
-            * [MatrixRank](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MatrixRank.java)
-            * [MatrixTranspose](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MatrixTranspose.java)
-            * [MedianOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java)
-            * [MirrorOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java)
-            * [PrintAMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java)
-            * [RotateMatrixBy90Degrees](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java)
-            * [SolveSystem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/SolveSystem.java)
-            * utils
-              * [MatrixUtil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/matrix/utils/MatrixUtil.java)
-          * misc
-            * [ColorContrastRatio](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ColorContrastRatio.java)
-            * [MapReduce](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MapReduce.java)
-            * [MedianOfRunningArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java)
-            * [MedianOfRunningArrayByte](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayByte.java)
-            * [MedianOfRunningArrayDouble](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayDouble.java)
-            * [MedianOfRunningArrayFloat](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayFloat.java)
-            * [MedianOfRunningArrayInteger](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayInteger.java)
-            * [MedianOfRunningArrayLong](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/MedianOfRunningArrayLong.java)
-            * [PalindromePrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromePrime.java)
-            * [PalindromeSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java)
-            * [RangeInSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java)
-            * [ShuffleArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ShuffleArray.java)
-            * [Sparsity](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sparsity.java)
-            * [ThreeSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java)
-            * [TwoSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/TwoSumProblem.java)
-          * others
-            * [ArrayLeftRotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ArrayLeftRotation.java)
-            * [ArrayRightRotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ArrayRightRotation.java)
-            * [BankersAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/BankersAlgorithm.java)
-            * [BFPRT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/BFPRT.java)
-            * [BoyerMoore](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/BoyerMoore.java)
-            * [BrianKernighanAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/BrianKernighanAlgorithm.java)
-            * cn
-              * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/cn/HammingDistance.java)
-            * [Conway](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Conway.java)
-            * [CRC16](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CRC16.java)
-            * [CRC32](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CRC32.java)
-            * [CRCAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/CRCAlgorithm.java)
-            * [Damm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Damm.java)
-            * [Dijkstra](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Dijkstra.java)
-            * [FloydTriangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/FloydTriangle.java)
-            * [GaussLegendre](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/GaussLegendre.java)
-            * [HappyNumbersSeq](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java)
-            * [Huffman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Huffman.java)
-            * [Implementing auto completing features using trie](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java)
-            * [InsertDeleteInArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java)
-            * [KochSnowflake](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/KochSnowflake.java)
-            * [Krishnamurthy](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Krishnamurthy.java)
-            * [LinearCongruentialGenerator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/LinearCongruentialGenerator.java)
-            * [LineSweep](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/LineSweep.java)
-            * [LowestBasePalindrome](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java)
-            * [Luhn](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Luhn.java)
-            * [Mandelbrot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Mandelbrot.java)
-            * [MaximumSlidingWindow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java)
-            * [MaximumSumOfDistinctSubarraysWithLengthK](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java)
-            * [MemoryManagementAlgorithms](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java)
-            * [MiniMaxAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java)
-            * [PageRank](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PageRank.java)
-            * [PasswordGen](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PasswordGen.java)
-            * [PerlinNoise](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PerlinNoise.java)
-            * [PrintAMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java)
-            * [QueueUsingTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java)
-            * [RemoveDuplicateFromString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java)
-            * [ReverseStackUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
-            * [SkylineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SkylineProblem.java)
-            * [TwoPointers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TwoPointers.java)
-            * [Verhoeff](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Verhoeff.java)
-          * puzzlesandgames
-            * [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java)
-            * [TowerOfHanoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java)
-            * [WordBoggle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/puzzlesandgames/WordBoggle.java)
-          * randomized
-            * [KargerMinCut](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/randomized/KargerMinCut.java)
-            * [MonteCarloIntegration](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java)
-            * [RandomizedQuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/randomized/RandomizedQuickSort.java)
-            * [ReservoirSampling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/randomized/ReservoirSampling.java)
-          * recursion
-            * [FibonacciSeries](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java)
-            * [GenerateSubsets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/recursion/GenerateSubsets.java)
-          * scheduling
-            * [AgingScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/AgingScheduling.java)
-            * diskscheduling
-              * [CircularLookScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularLookScheduling.java)
-              * [CircularScanScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularScanScheduling.java)
-              * [LookScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/LookScheduling.java)
-              * [ScanScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/ScanScheduling.java)
-              * [SSFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java)
-            * [EDFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/EDFScheduling.java)
-            * [FairShareScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FairShareScheduling.java)
-            * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
-            * [GangScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/GangScheduling.java)
-            * [HighestResponseRatioNextScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
-            * [JobSchedulingWithDeadline](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java)
-            * [LotteryScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/LotteryScheduling.java)
-            * [MLFQScheduler](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java)
-            * [MultiAgentScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MultiAgentScheduling.java)
-            * [NonPreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java)
-            * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
-            * [ProportionalFairScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java)
-            * [RandomScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RandomScheduling.java)
-            * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
-            * [SelfAdjustingScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java)
-            * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
-            * [SlackTimeScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SlackTimeScheduling.java)
-            * [SRTFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java)
-          * searches
-            * [BinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BinarySearch.java)
-            * [BinarySearch2dArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java)
-            * [BM25InvertedIndex](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java)
-            * [BreadthFirstSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java)
-            * [DepthFirstSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/DepthFirstSearch.java)
-            * [ExponentalSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/ExponentalSearch.java)
-            * [FibonacciSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/FibonacciSearch.java)
-            * [HowManyTimesRotated](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java)
-            * [InterpolationSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/InterpolationSearch.java)
-            * [IterativeBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java)
-            * [IterativeTernarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/IterativeTernarySearch.java)
-            * [JumpSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/JumpSearch.java)
-            * [KMPSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/KMPSearch.java)
-            * [LinearSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/LinearSearch.java)
-            * [LinearSearchThread](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/LinearSearchThread.java)
-            * [LowerBound](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/LowerBound.java)
-            * [MonteCarloTreeSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java)
-            * [OrderAgnosticBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java)
-            * [PerfectBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java)
-            * [QuickSelect](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/QuickSelect.java)
-            * [RabinKarpAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java)
-            * [RandomSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RandomSearch.java)
-            * [RecursiveBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java)
-            * [RowColumnWiseSorted2dArrayBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java)
-            * [SaddlebackSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SaddlebackSearch.java)
-            * [SearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java)
-            * [SortOrderAgnosticBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java)
-            * [SquareRootBinarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java)
-            * [TernarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/TernarySearch.java)
-            * [UnionFind](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UnionFind.java)
-            * [UpperBound](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UpperBound.java)
-          * slidingwindow
-            * [LongestSubarrayWithSumLessOrEqualToK](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToK.java)
-            * [LongestSubstringWithoutRepeatingCharacters](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java)
-            * [MaxSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java)
-            * [MinSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java)
-            * [ShortestCoprimeSegment](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegment.java)
-
-          * sorts
-            * [AdaptiveMergeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java)
-            * [BeadSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BeadSort.java)
-            * [BinaryInsertionSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java)
-            * [BitonicSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BitonicSort.java)
-            * [BogoSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BogoSort.java)
-            * [BubbleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BubbleSort.java)
-            * [BubbleSortRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BubbleSortRecursive.java)
-            * [BucketSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BucketSort.java)
-            * [CircleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CircleSort.java)
-            * [CocktailShakerSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java)
-            * [CombSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CombSort.java)
-            * [CountingSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CountingSort.java)
-            * [CycleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/CycleSort.java)
-            * [DarkSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DarkSort.java)
-            * [DualPivotQuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java)
-            * [DutchNationalFlagSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java)
-            * [ExchangeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/ExchangeSort.java)
-            * [FlashSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/FlashSort.java)
-            * [GnomeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/GnomeSort.java)
-            * [HeapSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/HeapSort.java)
-            * [InsertionSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/InsertionSort.java)
-            * [IntrospectiveSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java)
-            * [LinkListSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/LinkListSort.java)
-            * [MergeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/MergeSort.java)
-            * [MergeSortNoExtraSpace](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java)
-            * [MergeSortRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java)
-            * [OddEvenSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/OddEvenSort.java)
-            * [PancakeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/PancakeSort.java)
-            * [PatienceSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/PatienceSort.java)
-            * [PigeonholeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/PigeonholeSort.java)
-            * [QuickSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/QuickSort.java)
-            * [RadixSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/RadixSort.java)
-            * [SelectionSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SelectionSort.java)
-            * [SelectionSortRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java)
-            * [ShellSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/ShellSort.java)
-            * [SimpleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SimpleSort.java)
-            * [SlowSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SlowSort.java)
-            * [SortAlgorithm](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SortAlgorithm.java)
-            * [SortUtils](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SortUtils.java)
-            * [SortUtilsRandomGenerator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java)
-            * [SpreadSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SpreadSort.java)
-            * [StalinSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/StalinSort.java)
-            * [StoogeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/StoogeSort.java)
-            * [StrandSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/StrandSort.java)
-            * [SwapSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/SwapSort.java)
-            * [TimSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/TimSort.java)
-            * [TopologicalSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/TopologicalSort.java)
-            * [TreeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/TreeSort.java)
-            * [WaveSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/WaveSort.java)
-            * [WiggleSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/WiggleSort.java)
-          * stacks
-            * [BalancedBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/BalancedBrackets.java)
-            * [CelebrityFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/CelebrityFinder.java)
-            * [DecimalToAnyUsingStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java)
-            * [DuplicateBrackets](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java)
-            * [GreatestElementConstantTime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/GreatestElementConstantTime.java)
-            * [InfixToPostfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java)
-            * [InfixToPrefix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java)
-            * [LargestRectangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/LargestRectangle.java)
-            * [MaximumMinimumWindow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java)
-            * [MinStackUsingSingleStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MinStackUsingSingleStack.java)
-            * [MinStackUsingTwoStacks](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/MinStackUsingTwoStacks.java)
-            * [NextGreaterElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextGreaterElement.java)
-            * [NextSmallerElement](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
-            * [PalindromeWithStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java)
-            * [PostfixEvaluator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java)
-            * [PostfixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java)
-            * [PrefixEvaluator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PrefixEvaluator.java)
-            * [PrefixToInfix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/PrefixToInfix.java)
-            * [SmallestElementConstantTime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/SmallestElementConstantTime.java)
-            * [SortStack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/SortStack.java)
-            * [StackPostfixNotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
-            * [StackUsingTwoQueues](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/stacks/StackUsingTwoQueues.java)
-          * strings
-            * [AhoCorasick](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/AhoCorasick.java)
-            * [Alphabetical](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Alphabetical.java)
-            * [Anagrams](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Anagrams.java)
-            * [CharactersSame](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CharactersSame.java)
-            * [CheckAnagrams](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CheckAnagrams.java)
-            * [CheckVowels](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CheckVowels.java)
-            * [CountChar](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CountChar.java)
-            * [CountWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/CountWords.java)
-            * [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/HammingDistance.java)
-            * [HorspoolSearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/HorspoolSearch.java)
-            * [Isomorphic](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Isomorphic.java)
-            * [KMP](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/KMP.java)
-            * [LetterCombinationsOfPhoneNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java)
-            * [LongestCommonPrefix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java)
-            * [LongestNonRepetitiveSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java)
-            * [LongestPalindromicSubstring](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java)
-            * [Lower](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Lower.java)
-            * [Manacher](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Manacher.java)
-            * [MyAtoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/MyAtoi.java)
-            * [Palindrome](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Palindrome.java)
-            * [Pangram](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Pangram.java)
-            * [PermuteString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/PermuteString.java)
-            * [RabinKarp](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/RabinKarp.java)
-            * [ReturnSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReturnSubsequence.java)
-            * [ReverseString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseString.java)
-            * [ReverseStringRecursive](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java)
-            * [ReverseWordsInString](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ReverseWordsInString.java)
-            * [Rotation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Rotation.java)
-            * [StringCompression](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/StringCompression.java)
-            * [StringMatchFiniteAutomata](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/StringMatchFiniteAutomata.java)
-            * [Upper](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/Upper.java)
-            * [ValidParentheses](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/ValidParentheses.java)
-            * [WordLadder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/WordLadder.java)
-            * zigZagPattern
-              * [ZigZagPattern](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java)
-          * tree
-            * [HeavyLightDecomposition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java)
-  * test
-    * java
-      * com
-        * thealgorithms
-          * audiofilters
-            * [EMAFilterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/audiofilters/EMAFilterTest.java)
-            * [IIRFilterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/audiofilters/IIRFilterTest.java)
-          * backtracking
-            * [AllPathsFromSourceToTargetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/AllPathsFromSourceToTargetTest.java)
-            * [ArrayCombinationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java)
-            * [CombinationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/CombinationTest.java)
-            * [CrosswordSolverTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/CrosswordSolverTest.java)
-            * [FloodFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/FloodFillTest.java)
-            * [KnightsTourTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/KnightsTourTest.java)
-            * [MazeRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java)
-            * [MColoringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/MColoringTest.java)
-            * [NQueensTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/NQueensTest.java)
-            * [ParenthesesGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/ParenthesesGeneratorTest.java)
-            * [PermutationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PermutationTest.java)
-            * [PowerSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/PowerSumTest.java)
-            * [SubsequenceFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/SubsequenceFinderTest.java)
-            * [WordPatternMatcherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordPatternMatcherTest.java)
-            * [WordSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
-          * bitmanipulation
-            * [BcdConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java)
-            * [BinaryPalindromeCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java)
-            * [BitSwapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
-            * [BooleanAlgebraGatesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGatesTest.java)
-            * [ClearLeftmostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java)
-            * [CountLeadingZerosTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java)
-            * [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
-            * [FindNthBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/FindNthBitTest.java)
-            * [FirstDifferentBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/FirstDifferentBitTest.java)
-            * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java)
-            * [GrayCodeConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java)
-            * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java)
-            * [HigherLowerPowerOfTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java)
-            * [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
-            * [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
-            * [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
-            * [IsPowerTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java)
-            * [LowestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java)
-            * [ModuloPowerOfTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwoTest.java)
-            * [NextHigherSameBitCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCountTest.java)
-            * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
-            * [NumberAppearingOddTimesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java)
-            * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
-            * [OneBitDifferenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/OneBitDifferenceTest.java)
-            * [OnesComplementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java)
-            * [ParityCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java)
-            * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
-            * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
-            * [SingleElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleElementTest.java)
-            * [SwapAdjacentBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java)
-            * [TwosComplementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java)
-            * [Xs3ConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/Xs3ConversionTest.java)
-          * ciphers
-            * a5
-              * [A5CipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java)
-              * [A5KeyStreamGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java)
-              * [LFSRTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
-            * [ADFGVXCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java)
-            * [AESEncryptionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java)
-            * [AffineCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java)
-            * [AtbashTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AtbashTest.java)
-            * [AutokeyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
-            * [BaconianCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BaconianCipherTest.java)
-            * [BlowfishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
-            * [CaesarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
-            * [ColumnarTranspositionCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java)
-            * [DESTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DESTest.java)
-            * [DiffieHellmanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/DiffieHellmanTest.java)
-            * [ECCTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/ECCTest.java)
-            * [HillCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/HillCipherTest.java)
-            * [MonoAlphabeticTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/MonoAlphabeticTest.java)
-            * [PlayfairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PlayfairTest.java)
-            * [PolybiusTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
-            * [RailFenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RailFenceTest.java)
-            * [RSATest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/RSATest.java)
-            * [SimpleSubCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/SimpleSubCipherTest.java)
-            * [VigenereTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/VigenereTest.java)
-            * [XORCipherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/ciphers/XORCipherTest.java)
-          * conversions
-            * [AffineConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/AffineConverterTest.java)
-            * [AnyBaseToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java)
-            * [AnytoAnyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/AnytoAnyTest.java)
-            * [BinaryToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java)
-            * [BinaryToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java)
-            * [BinaryToOctalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java)
-            * [DecimalToAnyBaseTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToAnyBaseTest.java)
-            * [DecimalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToBinaryTest.java)
-            * [DecimalToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToHexadecimalTest.java)
-            * [DecimalToOctalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/DecimalToOctalTest.java)
-            * [EndianConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java)
-            * [HexaDecimalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java)
-            * [HexaDecimalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexaDecimalToDecimalTest.java)
-            * [HexToOctTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/HexToOctTest.java)
-            * [IntegerToEnglishTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java)
-            * [IntegerToRomanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java)
-            * [IPConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IPConverterTest.java)
-            * [IPv6ConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/IPv6ConverterTest.java)
-            * [MorseCodeConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/MorseCodeConverterTest.java)
-            * [NumberToWordsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/NumberToWordsTest.java)
-            * [OctalToBinaryTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java)
-            * [OctalToDecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java)
-            * [OctalToHexadecimalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
-            * [PhoneticAlphabetConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java)
-            * [RomanToIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java)
-            * [TurkishToLatinConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java)
-            * [UnitConversionsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java)
-            * [UnitsConverterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java)
-            * [WordsToNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/conversions/WordsToNumberTest.java)
-          * datastructures
-            * bag
-              * [BagTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java)
-            * bloomfilter
-              * [BloomFilterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java)
-            * buffers
-              * [CircularBufferTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java)
-            * caches
-              * [LFUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java)
-              * [LRUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java)
-              * [MRUCacheTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java)
-            * crdt
-              * [GCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java)
-              * [GSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java)
-              * [LWWElementSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java)
-              * [ORSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java)
-              * [PNCounterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java)
-              * [TwoPSetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java)
-            * disjointsetunion
-              * [DisjointSetUnionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java)
-            * dynamicarray
-              * [DynamicArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java)
-            * graphs
-              * [AStarTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java)
-              * [BipartiteGraphDFSTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java)
-              * [BoruvkaAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
-              * [DijkstraAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java)
-              * [DijkstraOptimizedAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java)
-              * [EdmondsBlossomAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java)
-              * [FloydWarshallTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FloydWarshallTest.java)
-              * [FordFulkersonTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java)
-              * [HamiltonianCycleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java)
-              * [JohnsonsAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java)
-              * [KahnsAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithmTest.java)
-              * [KosarajuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
-              * [KruskalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java)
-              * [MatrixGraphsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java)
-              * [PrimMSTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/PrimMSTTest.java)
-              * [TarjansAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
-              * [WelshPowellTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java)
-            * hashmap
-              * hashing
-                * [GenericHashMapUsingArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java)
-                * [GenericHashMapUsingArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java)
-                * [HashMapCuckooHashingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashingTest.java)
-                * [HashMapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java)
-                * [IntersectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/IntersectionTest.java)
-                * [LinearProbingHashMapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMapTest.java)
-                * [MajorityElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java)
-                * [MapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java)
-            * heaps
-              * [FibonacciHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
-              * [GenericHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java)
-              * [HeapElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java)
-              * [KthElementFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java)
-              * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
-              * [MaxHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MaxHeapTest.java)
-              * [MedianFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java)
-              * [MergeKSortedArraysTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MergeKSortedArraysTest.java)
-              * [MinHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MinHeapTest.java)
-              * [MinPriorityQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java)
-            * lists
-              * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
-              * [CountSinglyLinkedListRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java)
-              * [CreateAndDetectLoopTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java)
-              * [CursorLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java)
-              * [MergeKSortedLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java)
-              * [MergeSortedArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java)
-              * [MergeSortedSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java)
-              * [QuickSortLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java)
-              * [ReverseKGroupTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java)
-              * [RotateSinglyLinkedListsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java)
-              * [SearchSinglyLinkedListRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursionTest.java)
-              * [SinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java)
-              * [SkipListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java)
-              * [SortedLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java)
-            * queues
-              * [CircularQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java)
-              * [DequeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java)
-              * [GenericArrayListQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java)
-              * [LinkedQueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java)
-              * [PriorityQueuesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java)
-              * [QueueByTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java)
-              * [QueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java)
-              * [SlidingWindowMaximumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximumTest.java)
-              * [TokenBucketTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/TokenBucketTest.java)
-            * stacks
-              * [NodeStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java)
-              * [ReverseStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java)
-              * [StackArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java)
-              * [StackArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java)
-              * [StackOfLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java)
-            * trees
-              * [AVLTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/AVLTreeTest.java)
-              * [BinaryTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java)
-              * [BoundaryTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BoundaryTraversalTest.java)
-              * [BSTFromSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTFromSortedArrayTest.java)
-              * [BSTIterativeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTIterativeTest.java)
-              * [BSTRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveTest.java)
-              * [BTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/BTreeTest.java)
-              * [CeilInBinarySearchTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTreeTest.java)
-              * [CheckBinaryTreeIsValidBSTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBSTTest.java)
-              * [CheckIfBinaryTreeBalancedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalancedTest.java)
-              * [CheckTreeIsSymmetricTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetricTest.java)
-              * [CreateBinaryTreeFromInorderPreorderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorderTest.java)
-              * [InorderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/InorderTraversalTest.java)
-              * [KDTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/KDTreeTest.java)
-              * [LazySegmentTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java)
-              * [LevelOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/LevelOrderTraversalTest.java)
-              * [PostOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/PostOrderTraversalTest.java)
-              * [PreOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/PreOrderTraversalTest.java)
-              * [QuadTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/QuadTreeTest.java)
-              * [SameTreesCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SameTreesCheckTest.java)
-              * [SplayTreeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java)
-              * [TreapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java)
-              * [TreeTestUtils](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java)
-              * [TrieTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/TrieTest.java)
-              * [VerticalOrderTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversalTest.java)
-              * [ZigzagTraversalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/trees/ZigzagTraversalTest.java)
-          * divideandconquer
-            * [BinaryExponentiationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java)
-            * [ClosestPairTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java)
-            * [CountingInversionsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java)
-            * [MedianOfTwoSortedArraysTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArraysTest.java)
-            * [SkylineAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java)
-            * [StrassenMatrixMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
-            * [TilingProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/divideandconquer/TilingProblemTest.java)
-          * dynamicprogramming
-            * [AbbreviationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/AbbreviationTest.java)
-            * [AllConstructTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java)
-            * [AssignmentUsingBitmaskTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java)
-            * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
-            * [BoundaryFillTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java)
-            * [BruteForceKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java)
-            * [CatalanNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java)
-            * [ClimbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java)
-            * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CoinChangeTest.java)
-            * [CountFriendsPairingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java)
-            * [DPTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/DPTest.java)
-            * [EditDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java)
-            * [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
-            * [FibonacciTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/FibonacciTest.java)
-            * [KadaneAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithmTest.java)
-            * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
-            * [KnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
-            * [LevenshteinDistanceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
-            * [LongestAlternatingSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java)
-            * [LongestArithmeticSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequenceTest.java)
-            * [LongestCommonSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java)
-            * [LongestIncreasingSubsequenceNLogNTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogNTest.java)
-            * [LongestIncreasingSubsequenceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java)
-            * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java)
-            * [LongestValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java)
-            * [MatrixChainMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplicationTest.java)
-            * [MatrixChainRecursiveTopDownMemoisationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisationTest.java)
-            * [MaximumSumOfNonAdjacentElementsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElementsTest.java)
-            * [MinimumPathSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java)
-            * [MinimumSumPartitionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java)
-            * [NewManShanksPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/NewManShanksPrimeTest.java)
-            * [OptimalJobSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
-            * [PalindromicPartitioningTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioningTest.java)
-            * [PartitionProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java)
-            * [RegexMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/RegexMatchingTest.java)
-            * [RodCuttingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java)
-            * [ShortestCommonSupersequenceLengthTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLengthTest.java)
-            * [SubsetCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java)
-            * [SubsetSumSpaceOptimizedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimizedTest.java)
-            * [SubsetSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java)
-            * [SumOfSubsetTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java)
-            * [TreeMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/TreeMatchingTest.java)
-            * [TribonacciTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java)
-            * [UniquePathsTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java)
-            * [UniqueSubsequencesCountTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCountTest.java)
-            * [WildcardMatchingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java)
-            * [WineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/WineProblemTest.java)
-          * geometry
-            * [BresenhamLineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java)
-            * [ConvexHullTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java)
-            * [GrahamScanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
-            * [MidpointCircleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java)
-            * [MidpointEllipseTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java)
-          * graph
-            * [ConstrainedShortestPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java)
-            * [StronglyConnectedComponentOptimizedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/
-            * [TravelingSalesmanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java)
-StronglyConnectedComponentOptimizedTest.java)
-          * greedyalgorithms
-            * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
-            * [BandwidthAllocationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java)
-            * [BinaryAdditionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java)
-            * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java)
-            * [DigitSeparationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java)
-            * [EgyptianFractionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/EgyptianFractionTest.java)
-            * [FractionalKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
-            * [GaleShapleyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java)
-            * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
-            * [KCentersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/KCentersTest.java)
-            * [MergeIntervalsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java)
-            * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java)
-            * [MinimumWaitingTimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTimeTest.java)
-            * [OptimalFileMergingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java)
-            * [StockProfitCalculatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java)
-          * io
-            * [BufferedReaderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/io/BufferedReaderTest.java)
-          * lineclipping
-            * [CohenSutherlandTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/lineclipping/CohenSutherlandTest.java)
-            * [LiangBarskyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/lineclipping/LiangBarskyTest.java)
-          * maths
-            * [AbsoluteMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java)
-            * [AbsoluteMinTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java)
-            * [AbsoluteValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AbsoluteValueTest.java)
-            * [ADTFractionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ADTFractionTest.java)
-            * [AliquotSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AliquotSumTest.java)
-            * [AmicableNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AmicableNumberTest.java)
-            * [AreaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AreaTest.java)
-            * [ArmstrongTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ArmstrongTest.java)
-            * [AutoCorrelationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AutoCorrelationTest.java)
-            * [AutomorphicNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AutomorphicNumberTest.java)
-            * [AverageTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AverageTest.java)
-            * [BinaryPowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinaryPowTest.java)
-            * [BinomialCoefficientTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinomialCoefficientTest.java)
-            * [CatalanNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CatalanNumbersTest.java)
-            * [CeilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CeilTest.java)
-            * [ChineseRemainderTheoremTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java)
-            * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
-            * [CombinationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CombinationsTest.java)
-            * [ConvolutionFFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java)
-            * [ConvolutionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ConvolutionTest.java)
-            * [CrossCorrelationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java)
-            * [DeterminantOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DeterminantOfMatrixTest.java)
-            * [DigitalRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DigitalRootTest.java)
-            * [DistanceFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java)
-            * [DudeneyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java)
-            * [EulerMethodTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/EulerMethodTest.java)
-            * [EulersFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/EulersFunctionTest.java)
-            * [FactorialRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java)
-            * [FactorialTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialTest.java)
-            * [FastExponentiationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FastExponentiationTest.java)
-            * [FastInverseSqrtTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java)
-            * [FFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FFTTest.java)
-            * [FibonacciJavaStreamsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciJavaStreamsTest.java)
-            * [FibonacciLoopTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciLoopTest.java)
-            * [FibonacciNumberCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciNumberCheckTest.java)
-            * [FibonacciNumberGoldenRationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FibonacciNumberGoldenRationTest.java)
-            * [FindKthNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindKthNumberTest.java)
-            * [FindMaxRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java)
-            * [FindMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMaxTest.java)
-            * [FindMinRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMinRecursionTest.java)
-            * [FindMinTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FindMinTest.java)
-            * [FloorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FloorTest.java)
-            * [FrizzyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FrizzyNumberTest.java)
-            * [GaussianTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GaussianTest.java)
-            * [GCDRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GCDRecursionTest.java)
-            * [GCDTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GCDTest.java)
-            * [GenericRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GenericRootTest.java)
-            * [GoldbachConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/GoldbachConjectureTest.java)
-            * [HarshadNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java)
-            * [HeronsFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java)
-            * [JosephusProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/JosephusProblemTest.java)
-            * [KaprekarNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java)
-            * [KaratsubaMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java)
-            * [KrishnamurthyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java)
-            * [LeastCommonMultipleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java)
-            * [LeonardoNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java)
-            * [LongDivisionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LongDivisionTest.java)
-            * [LucasSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LucasSeriesTest.java)
-            * [MathBuilderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MathBuilderTest.java)
-            * [MaxValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MaxValueTest.java)
-            * [MeansTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MeansTest.java)
-            * [MedianTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MedianTest.java)
-            * [MinValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MinValueTest.java)
-            * [ModeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ModeTest.java)
-            * [NonRepeatingElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NonRepeatingElementTest.java)
-            * [NthUglyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java)
-            * [NumberOfDigitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java)
-            * [PalindromeNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java)
-            * [ParseIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ParseIntegerTest.java)
-            * [PascalTriangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PascalTriangleTest.java)
-            * [PerfectCubeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PerfectCubeTest.java)
-            * [PerfectNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PerfectNumberTest.java)
-            * [PerfectSquareTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PerfectSquareTest.java)
-            * [PerimeterTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PerimeterTest.java)
-            * [PollardRhoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PollardRhoTest.java)
-            * [PowerOfTwoOrNotTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java)
-            * [PowerUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java)
-            * [PowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PowTest.java)
-            * prime
-              * [LiouvilleLambdaFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/prime/LiouvilleLambdaFunctionTest.java)
-              * [MillerRabinPrimalityCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/prime/MillerRabinPrimalityCheckTest.java)
-              * [MobiusFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/prime/MobiusFunctionTest.java)
-              * [PrimeCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/prime/PrimeCheckTest.java)
-              * [PrimeFactorizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/prime/PrimeFactorizationTest.java)
-            * [PronicNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PronicNumberTest.java)
-            * [PythagoreanTripleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java)
-            * [QuadraticEquationSolverTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java)
-            * [ReverseNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ReverseNumberTest.java)
-            * [SecondMinMaxTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java)
-            * [SieveOfEratosthenesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java)
-            * [SolovayStrassenPrimalityTestTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SolovayStrassenPrimalityTestTest.java)
-            * [SquareFreeIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java)
-            * [SquareRootwithBabylonianMethodTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareRootwithBabylonianMethodTest.java)
-            * [SquareRootWithNewtonRaphsonTestMethod](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonTestMethod.java)
-            * [StandardDeviationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/StandardDeviationTest.java)
-            * [StandardScoreTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/StandardScoreTest.java)
-            * [StrobogrammaticNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/StrobogrammaticNumberTest.java)
-            * [SumOfArithmeticSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SumOfArithmeticSeriesTest.java)
-            * [SumOfDigitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SumOfDigitsTest.java)
-            * [SumOfOddNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java)
-            * [SumWithoutArithmeticOperatorsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SumWithoutArithmeticOperatorsTest.java)
-            * [TestArmstrong](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TestArmstrong.java)
-            * [TwinPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TwinPrimeTest.java)
-            * [UniformNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/UniformNumbersTest.java)
-            * [VampireNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/VampireNumberTest.java)
-            * [VolumeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/VolumeTest.java)
-          * matrix
-            * [InverseOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/InverseOfMatrixTest.java)
-            * [MatrixRankTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MatrixRankTest.java)
-            * [MatrixTransposeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MatrixTransposeTest.java)
-            * [MatrixUtilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MatrixUtilTest.java)
-            * [MedianOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java)
-            * [MirrorOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java)
-            * [SolveSystemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/SolveSystemTest.java)
-            * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java)
-          * misc
-            * [ColorContrastRatioTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java)
-            * [MapReduceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MapReduceTest.java)
-            * [MedianOfRunningArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java)
-            * [PalindromePrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java)
-            * [PalindromeSinglyLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java)
-            * [RangeInSortedArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java)
-            * [ShuffleArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java)
-            * [SparsityTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/SparsityTest.java)
-            * [ThreeSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java)
-            * [TwoSumProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
-          * others
-            * [ArrayLeftRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java)
-            * [ArrayRightRotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java)
-            * [BestFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BestFitCPUTest.java)
-            * [BFPRTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BFPRTTest.java)
-            * [BoyerMooreTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/BoyerMooreTest.java)
-            * cn
-              * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java)
-            * [ConwayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ConwayTest.java)
-            * [CountFriendsPairingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CountFriendsPairingTest.java)
-            * [CRC16Test](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CRC16Test.java)
-            * [CRCAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java)
-            * [FirstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/FirstFitCPUTest.java)
-            * [FloydTriangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/FloydTriangleTest.java)
-            * [KadaneAlogrithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java)
-            * [LineSweepTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/LineSweepTest.java)
-            * [LinkListSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/LinkListSortTest.java)
-            * [LowestBasePalindromeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java)
-            * [MaximumSlidingWindowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java)
-            * [MaximumSumOfDistinctSubarraysWithLengthKTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java)
-            * [NewManShanksPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java)
-            * [NextFitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/NextFitTest.java)
-            * [PasswordGenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/PasswordGenTest.java)
-            * [QueueUsingTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java)
-            * [RemoveDuplicateFromStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java)
-            * [ReverseStackUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
-            * [SkylineProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
-            * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
-            * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
-            * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
-          * puzzlesandgames
-            * [SudokuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java)
-            * [TowerOfHanoiTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java)
-            * [WordBoggleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/puzzlesandgames/WordBoggleTest.java)
-          * randomize
-            * [KargerMinCutTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/randomized/KargerMinCutTest.java)
-            * [MonteCarloIntegrationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/randomized/MonteCarloIntegrationTest.java)
-            * [RandomizedQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/randomized/RandomizedQuickSortTest.java)
-            * [ReservoirSamplingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/randomized/ReservoirSamplingTest.java)
-          * recursion
-            * [FibonacciSeriesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/recursion/FibonacciSeriesTest.java)
-            * [GenerateSubsetsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java)
-          * scheduling
-            * [AgingSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/AgingSchedulingTest.java)
-            * diskscheduling
-              * [CircularLookSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java)
-              * [CircularScanSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java)
-              * [LookSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java)
-              * [ScanSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java)
-              * [SSFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/diskscheduling/SSFSchedulingTest.java)
-            * [EDFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java)
-            * [FairShareSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FairShareSchedulingTest.java)
-            * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
-            * [GangSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/GangSchedulingTest.java)
-            * [HighestResponseRatioNextSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
-            * [JobSchedulingWithDeadlineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java)
-            * [LotterySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/LotterySchedulingTest.java)
-            * [MLFQSchedulerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java)
-            * [MultiAgentSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MultiAgentSchedulingTest.java)
-            * [NonPreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java)
-            * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
-            * [ProportionalFairSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java)
-            * [RandomSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java)
-            * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
-            * [SelfAdjustingSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java)
-            * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)
-            * [SlackTimeSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SlackTimeSchedulingTest.java)
-            * [SRTFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java)
-          * searches
-            * [BinarySearch2dArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java)
-            * [BinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BinarySearchTest.java)
-            * [BM25InvertedIndexTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java)
-            * [BreadthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java)
-            * [DepthFirstSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java)
-            * [ExponentialSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java)
-            * [FibonacciSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java)
-            * [HowManyTimesRotatedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java)
-            * [InterpolationSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java)
-            * [IterativeBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java)
-            * [IterativeTernarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/IterativeTernarySearchTest.java)
-            * [JumpSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/JumpSearchTest.java)
-            * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
-            * [LinearSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/LinearSearchTest.java)
-            * [LinearSearchThreadTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java)
-            * [LowerBoundTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/LowerBoundTest.java)
-            * [MonteCarloTreeSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/MonteCarloTreeSearchTest.java)
-            * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
-            * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
-            * [QuickSelectTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/QuickSelectTest.java)
-            * [RabinKarpAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java)
-            * [RandomSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RandomSearchTest.java)
-            * [RecursiveBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java)
-            * [RowColumnWiseSorted2dArrayBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java)
-            * [SaddlebackSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SaddlebackSearchTest.java)
-            * [SearchInARowAndColWiseSortedMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java)
-            * [SortOrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
-            * [SquareRootBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java)
-            * [TernarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TernarySearchTest.java)
-            * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
-            * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java)
-            * [UpperBoundTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UpperBoundTest.java)
-          * slidingwindow
-            * [LongestSubarrayWithSumLessOrEqualToKTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToKTest.java)
-            * [LongestSubstringWithoutRepeatingCharactersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java)
-            * [MaxSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java)
-            * [MinSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java)
-            * [ShortestCoprimeSegmentTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegmentTest.java)
-          * sorts
-            * [AdaptiveMergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java)
-            * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
-            * [BinaryInsertionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java)
-            * [BitonicSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java)
-            * [BogoSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BogoSortTest.java)
-            * [BubbleSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BubbleSortRecursiveTest.java)
-            * [BubbleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BubbleSortTest.java)
-            * [BucketSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BucketSortTest.java)
-            * [CircleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CircleSortTest.java)
-            * [CocktailShakerSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java)
-            * [CombSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CombSortTest.java)
-            * [CountingSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CountingSortTest.java)
-            * [CycleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CycleSortTest.java)
-            * [DarkSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DarkSortTest.java)
-            * [DualPivotQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java)
-            * [DutchNationalFlagSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java)
-            * [ExchangeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/ExchangeSortTest.java)
-            * [FlashSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/FlashSortTest.java)
-            * [GnomeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/GnomeSortTest.java)
-            * [HeapSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/HeapSortTest.java)
-            * [InsertionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java)
-            * [IntrospectiveSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java)
-            * [MergeSortNoExtraSpaceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/MergeSortNoExtraSpaceTest.java)
-            * [MergeSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/MergeSortRecursiveTest.java)
-            * [MergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/MergeSortTest.java)
-            * [OddEvenSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/OddEvenSortTest.java)
-            * [PancakeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java)
-            * [PatienceSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PatienceSortTest.java)
-            * [PigeonholeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/PigeonholeSortTest.java)
-            * [QuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/QuickSortTest.java)
-            * [RadixSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/RadixSortTest.java)
-            * [SelectionSortRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java)
-            * [SelectionSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SelectionSortTest.java)
-            * [ShellSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/ShellSortTest.java)
-            * [SimpleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SimpleSortTest.java)
-            * [SlowSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SlowSortTest.java)
-            * [SortingAlgorithmTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java)
-            * [SortUtilsRandomGeneratorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortUtilsRandomGeneratorTest.java)
-            * [SortUtilsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SortUtilsTest.java)
-            * [SpreadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SpreadSortTest.java)
-            * [StalinSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StalinSortTest.java)
-            * [StoogeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StoogeSortTest.java)
-            * [StrandSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/StrandSortTest.java)
-            * [SwapSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/SwapSortTest.java)
-            * [TimSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TimSortTest.java)
-            * [TopologicalSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java)
-            * [TreeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/TreeSortTest.java)
-            * [WaveSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WaveSortTest.java)
-            * [WiggleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java)
-          * stacks
-            * [BalancedBracketsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/BalancedBracketsTest.java)
-            * [CelebrityFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/CelebrityFinderTest.java)
-            * [DecimalToAnyUsingStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/DecimalToAnyUsingStackTest.java)
-            * [DuplicateBracketsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java)
-            * [GreatestElementConstantTimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/GreatestElementConstantTimeTest.java)
-            * [InfixToPostfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java)
-            * [InfixToPrefixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java)
-            * [LargestRectangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java)
-            * [MinStackUsingSingleStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/MinStackUsingSingleStackTest.java)
-            * [MinStackUsingTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java)
-            * [NextGreaterElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java)
-            * [NextSmallerElementTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
-            * [PalindromeWithStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PalindromeWithStackTest.java)
-            * [PostfixEvaluatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java)
-            * [PostfixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java)
-            * [PrefixEvaluatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java)
-            * [PrefixToInfixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java)
-            * [SmallestElementConstantTimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/SmallestElementConstantTimeTest.java)
-            * [SortStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/SortStackTest.java)
-            * [StackPostfixNotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
-            * [StackUsingTwoQueuesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/stacks/StackUsingTwoQueuesTest.java)
-          * strings
-            * [AhoCorasickTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
-            * [AlphabeticalTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java)
-            * [AnagramsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/AnagramsTest.java)
-            * [CharacterSameTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CharacterSameTest.java)
-            * [CharactersSameTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CharactersSameTest.java)
-            * [CheckAnagramsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CheckAnagramsTest.java)
-            * [CheckVowelsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CheckVowelsTest.java)
-            * [CountCharTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CountCharTest.java)
-            * [CountWordsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/CountWordsTest.java)
-            * [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HammingDistanceTest.java)
-            * [HorspoolSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java)
-            * [IsomorphicTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/IsomorphicTest.java)
-            * [LetterCombinationsOfPhoneNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java)
-            * [LongestCommonPrefixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java)
-            * [LongestNonRepetitiveSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java)
-            * [LongestPalindromicSubstringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java)
-            * [LowerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/LowerTest.java)
-            * [ManacherTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ManacherTest.java)
-            * [MyAtoiTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/MyAtoiTest.java)
-            * [PalindromeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PalindromeTest.java)
-            * [PangramTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PangramTest.java)
-            * [PermuteStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/PermuteStringTest.java)
-            * [ReturnSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReturnSubsequenceTest.java)
-            * [ReverseStringRecursiveTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java)
-            * [ReverseStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseStringTest.java)
-            * [ReverseWordsInStringTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java)
-            * [RotationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/RotationTest.java)
-            * [StringCompressionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/StringCompressionTest.java)
-            * [StringMatchFiniteAutomataTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/StringMatchFiniteAutomataTest.java)
-            * [UpperTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/UpperTest.java)
-            * [ValidParenthesesTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java)
-            * [WordLadderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/WordLadderTest.java)
-            * zigZagPattern
-              * [ZigZagPatternTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java)
-          * tree
-            * [HeavyLightDecompositionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java)
+- 📁 **main**
+  - 📁 **java**
+    - 📁 **com**
+      - 📁 **thealgorithms**
+        - 📁 **audiofilters**
+          - 📄 [EMAFilter](src/main/java/com/thealgorithms/audiofilters/EMAFilter.java)
+          - 📄 [IIRFilter](src/main/java/com/thealgorithms/audiofilters/IIRFilter.java)
+        - 📁 **backtracking**
+          - 📄 [AllPathsFromSourceToTarget](src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java)
+          - 📄 [ArrayCombination](src/main/java/com/thealgorithms/backtracking/ArrayCombination.java)
+          - 📄 [Combination](src/main/java/com/thealgorithms/backtracking/Combination.java)
+          - 📄 [CrosswordSolver](src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java)
+          - 📄 [FloodFill](src/main/java/com/thealgorithms/backtracking/FloodFill.java)
+          - 📄 [KnightsTour](src/main/java/com/thealgorithms/backtracking/KnightsTour.java)
+          - 📄 [MColoring](src/main/java/com/thealgorithms/backtracking/MColoring.java)
+          - 📄 [MazeRecursion](src/main/java/com/thealgorithms/backtracking/MazeRecursion.java)
+          - 📄 [NQueens](src/main/java/com/thealgorithms/backtracking/NQueens.java)
+          - 📄 [ParenthesesGenerator](src/main/java/com/thealgorithms/backtracking/ParenthesesGenerator.java)
+          - 📄 [Permutation](src/main/java/com/thealgorithms/backtracking/Permutation.java)
+          - 📄 [PowerSum](src/main/java/com/thealgorithms/backtracking/PowerSum.java)
+          - 📄 [SubsequenceFinder](src/main/java/com/thealgorithms/backtracking/SubsequenceFinder.java)
+          - 📄 [WordPatternMatcher](src/main/java/com/thealgorithms/backtracking/WordPatternMatcher.java)
+          - 📄 [WordSearch](src/main/java/com/thealgorithms/backtracking/WordSearch.java)
+        - 📁 **bitmanipulation**
+          - 📄 [BcdConversion](src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java)
+          - 📄 [BinaryPalindromeCheck](src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java)
+          - 📄 [BitSwap](src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
+          - 📄 [BooleanAlgebraGates](src/main/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGates.java)
+          - 📄 [ClearLeftmostSetBit](src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java)
+          - 📄 [CountLeadingZeros](src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java)
+          - 📄 [CountSetBits](src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
+          - 📄 [FindNthBit](src/main/java/com/thealgorithms/bitmanipulation/FindNthBit.java)
+          - 📄 [FirstDifferentBit](src/main/java/com/thealgorithms/bitmanipulation/FirstDifferentBit.java)
+          - 📄 [GenerateSubsets](src/main/java/com/thealgorithms/bitmanipulation/GenerateSubsets.java)
+          - 📄 [GrayCodeConversion](src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java)
+          - 📄 [HammingDistance](src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java)
+          - 📄 [HigherLowerPowerOfTwo](src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java)
+          - 📄 [HighestSetBit](src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
+          - 📄 [IndexOfRightMostSetBit](src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
+          - 📄 [IsEven](src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
+          - 📄 [IsPowerTwo](src/main/java/com/thealgorithms/bitmanipulation/IsPowerTwo.java)
+          - 📄 [LowestSetBit](src/main/java/com/thealgorithms/bitmanipulation/LowestSetBit.java)
+          - 📄 [ModuloPowerOfTwo](src/main/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwo.java)
+          - 📄 [NextHigherSameBitCount](src/main/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCount.java)
+          - 📄 [NonRepeatingNumberFinder](src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
+          - 📄 [NumberAppearingOddTimes](src/main/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimes.java)
+          - 📄 [NumbersDifferentSigns](src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
+          - 📄 [OneBitDifference](src/main/java/com/thealgorithms/bitmanipulation/OneBitDifference.java)
+          - 📄 [OnesComplement](src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java)
+          - 📄 [ParityCheck](src/main/java/com/thealgorithms/bitmanipulation/ParityCheck.java)
+          - 📄 [ReverseBits](src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
+          - 📄 [SingleBitOperations](src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java)
+          - 📄 [SingleElement](src/main/java/com/thealgorithms/bitmanipulation/SingleElement.java)
+          - 📄 [SwapAdjacentBits](src/main/java/com/thealgorithms/bitmanipulation/SwapAdjacentBits.java)
+          - 📄 [TwosComplement](src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java)
+          - 📄 [Xs3Conversion](src/main/java/com/thealgorithms/bitmanipulation/Xs3Conversion.java)
+        - 📁 **ciphers**
+          - 📄 [ADFGVXCipher](src/main/java/com/thealgorithms/ciphers/ADFGVXCipher.java)
+          - 📄 [AES](src/main/java/com/thealgorithms/ciphers/AES.java)
+          - 📄 [AESEncryption](src/main/java/com/thealgorithms/ciphers/AESEncryption.java)
+          - 📄 [AffineCipher](src/main/java/com/thealgorithms/ciphers/AffineCipher.java)
+          - 📄 [AtbashCipher](src/main/java/com/thealgorithms/ciphers/AtbashCipher.java)
+          - 📄 [Autokey](src/main/java/com/thealgorithms/ciphers/Autokey.java)
+          - 📄 [BaconianCipher](src/main/java/com/thealgorithms/ciphers/BaconianCipher.java)
+          - 📄 [Blowfish](src/main/java/com/thealgorithms/ciphers/Blowfish.java)
+          - 📄 [Caesar](src/main/java/com/thealgorithms/ciphers/Caesar.java)
+          - 📄 [ColumnarTranspositionCipher](src/main/java/com/thealgorithms/ciphers/ColumnarTranspositionCipher.java)
+          - 📄 [DES](src/main/java/com/thealgorithms/ciphers/DES.java)
+          - 📄 [DiffieHellman](src/main/java/com/thealgorithms/ciphers/DiffieHellman.java)
+          - 📄 [ECC](src/main/java/com/thealgorithms/ciphers/ECC.java)
+          - 📄 [HillCipher](src/main/java/com/thealgorithms/ciphers/HillCipher.java)
+          - 📄 [MonoAlphabetic](src/main/java/com/thealgorithms/ciphers/MonoAlphabetic.java)
+          - 📄 [PlayfairCipher](src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java)
+          - 📄 [Polybius](src/main/java/com/thealgorithms/ciphers/Polybius.java)
+          - 📄 [ProductCipher](src/main/java/com/thealgorithms/ciphers/ProductCipher.java)
+          - 📄 [RSA](src/main/java/com/thealgorithms/ciphers/RSA.java)
+          - 📄 [RailFenceCipher](src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java)
+          - 📄 [SimpleSubCipher](src/main/java/com/thealgorithms/ciphers/SimpleSubCipher.java)
+          - 📄 [Vigenere](src/main/java/com/thealgorithms/ciphers/Vigenere.java)
+          - 📄 [XORCipher](src/main/java/com/thealgorithms/ciphers/XORCipher.java)
+          - 📁 **a5**
+            - 📄 [A5Cipher](src/main/java/com/thealgorithms/ciphers/a5/A5Cipher.java)
+            - 📄 [A5KeyStreamGenerator](src/main/java/com/thealgorithms/ciphers/a5/A5KeyStreamGenerator.java)
+            - 📄 [BaseLFSR](src/main/java/com/thealgorithms/ciphers/a5/BaseLFSR.java)
+            - 📄 [CompositeLFSR](src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java)
+            - 📄 [LFSR](src/main/java/com/thealgorithms/ciphers/a5/LFSR.java)
+            - 📄 [Utils](src/main/java/com/thealgorithms/ciphers/a5/Utils.java)
+        - 📁 **conversions**
+          - 📄 [AffineConverter](src/main/java/com/thealgorithms/conversions/AffineConverter.java)
+          - 📄 [AnyBaseToAnyBase](src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java)
+          - 📄 [AnyBaseToDecimal](src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java)
+          - 📄 [AnytoAny](src/main/java/com/thealgorithms/conversions/AnytoAny.java)
+          - 📄 [BinaryToDecimal](src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java)
+          - 📄 [BinaryToHexadecimal](src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java)
+          - 📄 [BinaryToOctal](src/main/java/com/thealgorithms/conversions/BinaryToOctal.java)
+          - 📄 [DecimalToAnyBase](src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java)
+          - 📄 [DecimalToBinary](src/main/java/com/thealgorithms/conversions/DecimalToBinary.java)
+          - 📄 [DecimalToHexadecimal](src/main/java/com/thealgorithms/conversions/DecimalToHexadecimal.java)
+          - 📄 [DecimalToOctal](src/main/java/com/thealgorithms/conversions/DecimalToOctal.java)
+          - 📄 [EndianConverter](src/main/java/com/thealgorithms/conversions/EndianConverter.java)
+          - 📄 [HexToOct](src/main/java/com/thealgorithms/conversions/HexToOct.java)
+          - 📄 [HexaDecimalToBinary](src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java)
+          - 📄 [HexaDecimalToDecimal](src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java)
+          - 📄 [IPConverter](src/main/java/com/thealgorithms/conversions/IPConverter.java)
+          - 📄 [IPv6Converter](src/main/java/com/thealgorithms/conversions/IPv6Converter.java)
+          - 📄 [IntegerToEnglish](src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java)
+          - 📄 [IntegerToRoman](src/main/java/com/thealgorithms/conversions/IntegerToRoman.java)
+          - 📄 [MorseCodeConverter](src/main/java/com/thealgorithms/conversions/MorseCodeConverter.java)
+          - 📄 [NumberToWords](src/main/java/com/thealgorithms/conversions/NumberToWords.java)
+          - 📄 [OctalToBinary](src/main/java/com/thealgorithms/conversions/OctalToBinary.java)
+          - 📄 [OctalToDecimal](src/main/java/com/thealgorithms/conversions/OctalToDecimal.java)
+          - 📄 [OctalToHexadecimal](src/main/java/com/thealgorithms/conversions/OctalToHexadecimal.java)
+          - 📄 [PhoneticAlphabetConverter](src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java)
+          - 📄 [RgbHsvConversion](src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java)
+          - 📄 [RomanToInteger](src/main/java/com/thealgorithms/conversions/RomanToInteger.java)
+          - 📄 [TurkishToLatinConversion](src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java)
+          - 📄 [UnitConversions](src/main/java/com/thealgorithms/conversions/UnitConversions.java)
+          - 📄 [UnitsConverter](src/main/java/com/thealgorithms/conversions/UnitsConverter.java)
+          - 📄 [WordsToNumber](src/main/java/com/thealgorithms/conversions/WordsToNumber.java)
+        - 📁 **datastructures**
+          - 📄 [Node](src/main/java/com/thealgorithms/datastructures/Node.java)
+          - 📁 **bags**
+            - 📄 [Bag](src/main/java/com/thealgorithms/datastructures/bags/Bag.java)
+          - 📁 **bloomfilter**
+            - 📄 [BloomFilter](src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java)
+          - 📁 **buffers**
+            - 📄 [CircularBuffer](src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java)
+          - 📁 **caches**
+            - 📄 [LFUCache](src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java)
+            - 📄 [LRUCache](src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java)
+            - 📄 [MRUCache](src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java)
+          - 📁 **crdt**
+            - 📄 [GCounter](src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java)
+            - 📄 [GSet](src/main/java/com/thealgorithms/datastructures/crdt/GSet.java)
+            - 📄 [LWWElementSet](src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java)
+            - 📄 [ORSet](src/main/java/com/thealgorithms/datastructures/crdt/ORSet.java)
+            - 📄 [PNCounter](src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java)
+            - 📄 [TwoPSet](src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java)
+          - 📁 **disjointsetunion**
+            - 📄 [DisjointSetUnion](src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java)
+            - 📄 [Node](src/main/java/com/thealgorithms/datastructures/disjointsetunion/Node.java)
+          - 📁 **dynamicarray**
+            - 📄 [DynamicArray](src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java)
+          - 📁 **graphs**
+            - 📄 [AStar](src/main/java/com/thealgorithms/datastructures/graphs/AStar.java)
+            - 📄 [BellmanFord](src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java)
+            - 📄 [BipartiteGraphDFS](src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java)
+            - 📄 [BoruvkaAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithm.java)
+            - 📄 [ConnectedComponent](src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java)
+            - 📄 [Cycles](src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java)
+            - 📄 [DijkstraAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java)
+            - 📄 [DijkstraOptimizedAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java)
+            - 📄 [EdmondsBlossomAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java)
+            - 📄 [FloydWarshall](src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java)
+            - 📄 [FordFulkerson](src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java)
+            - 📄 [Graphs](src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java)
+            - 📄 [HamiltonianCycle](src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java)
+            - 📄 [JohnsonsAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java)
+            - 📄 [KahnsAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java)
+            - 📄 [Kosaraju](src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java)
+            - 📄 [Kruskal](src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java)
+            - 📄 [MatrixGraphs](src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java)
+            - 📄 [PrimMST](src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java)
+            - 📄 [README](src/main/java/com/thealgorithms/datastructures/graphs/README.md)
+            - 📄 [TarjansAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java)
+            - 📄 [UndirectedAdjacencyListGraph](src/main/java/com/thealgorithms/datastructures/graphs/UndirectedAdjacencyListGraph.java)
+            - 📄 [WelshPowell](src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java)
+          - 📁 **hashmap**
+            - 📄 [Readme](src/main/java/com/thealgorithms/datastructures/hashmap/Readme.md)
+            - 📁 **hashing**
+              - 📄 [GenericHashMapUsingArray](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java)
+              - 📄 [GenericHashMapUsingArrayList](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java)
+              - 📄 [HashMap](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java)
+              - 📄 [HashMapCuckooHashing](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java)
+              - 📄 [Intersection](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java)
+              - 📄 [LinearProbingHashMap](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java)
+              - 📄 [MainCuckooHashing](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java)
+              - 📄 [MajorityElement](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java)
+              - 📄 [Map](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Map.java)
+          - 📁 **heaps**
+            - 📄 [EmptyHeapException](src/main/java/com/thealgorithms/datastructures/heaps/EmptyHeapException.java)
+            - 📄 [FibonacciHeap](src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java)
+            - 📄 [GenericHeap](src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java)
+            - 📄 [Heap](src/main/java/com/thealgorithms/datastructures/heaps/Heap.java)
+            - 📄 [HeapElement](src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java)
+            - 📄 [KthElementFinder](src/main/java/com/thealgorithms/datastructures/heaps/KthElementFinder.java)
+            - 📄 [LeftistHeap](src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java)
+            - 📄 [MaxHeap](src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java)
+            - 📄 [MedianFinder](src/main/java/com/thealgorithms/datastructures/heaps/MedianFinder.java)
+            - 📄 [MergeKSortedArrays](src/main/java/com/thealgorithms/datastructures/heaps/MergeKSortedArrays.java)
+            - 📄 [MinHeap](src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java)
+            - 📄 [MinPriorityQueue](src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java)
+            - 📄 [Readme](src/main/java/com/thealgorithms/datastructures/heaps/Readme.md)
+          - 📁 **lists**
+            - 📄 [CircleLinkedList](src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java)
+            - 📄 [CountSinglyLinkedListRecursion](src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java)
+            - 📄 [CreateAndDetectLoop](src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java)
+            - 📄 [CursorLinkedList](src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java)
+            - 📄 [DoublyLinkedList](src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java)
+            - 📄 [MergeKSortedLinkedList](src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java)
+            - 📄 [MergeSortedArrayList](src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java)
+            - 📄 [MergeSortedSinglyLinkedList](src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java)
+            - 📄 [QuickSortLinkedList](src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java)
+            - 📄 [README](src/main/java/com/thealgorithms/datastructures/lists/README.md)
+            - 📄 [RandomNode](src/main/java/com/thealgorithms/datastructures/lists/RandomNode.java)
+            - 📄 [ReverseKGroup](src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java)
+            - 📄 [RotateSinglyLinkedLists](src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java)
+            - 📄 [SearchSinglyLinkedListRecursion](src/main/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursion.java)
+            - 📄 [SinglyLinkedList](src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedList.java)
+            - 📄 [SinglyLinkedListNode](src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedListNode.java)
+            - 📄 [SkipList](src/main/java/com/thealgorithms/datastructures/lists/SkipList.java)
+            - 📄 [SortedLinkedList](src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java)
+          - 📁 **queues**
+            - 📄 [CircularQueue](src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java)
+            - 📄 [Deque](src/main/java/com/thealgorithms/datastructures/queues/Deque.java)
+            - 📄 [GenericArrayListQueue](src/main/java/com/thealgorithms/datastructures/queues/GenericArrayListQueue.java)
+            - 📄 [LinkedQueue](src/main/java/com/thealgorithms/datastructures/queues/LinkedQueue.java)
+            - 📄 [PriorityQueues](src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java)
+            - 📄 [Queue](src/main/java/com/thealgorithms/datastructures/queues/Queue.java)
+            - 📄 [QueueByTwoStacks](src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java)
+            - 📄 [README](src/main/java/com/thealgorithms/datastructures/queues/README.md)
+            - 📄 [SlidingWindowMaximum](src/main/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximum.java)
+            - 📄 [TokenBucket](src/main/java/com/thealgorithms/datastructures/queues/TokenBucket.java)
+          - 📁 **stacks**
+            - 📄 [NodeStack](src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java)
+            - 📄 [README](src/main/java/com/thealgorithms/datastructures/stacks/README.md)
+            - 📄 [ReverseStack](src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java)
+            - 📄 [Stack](src/main/java/com/thealgorithms/datastructures/stacks/Stack.java)
+            - 📄 [StackArray](src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java)
+            - 📄 [StackArrayList](src/main/java/com/thealgorithms/datastructures/stacks/StackArrayList.java)
+            - 📄 [StackOfLinkedList](src/main/java/com/thealgorithms/datastructures/stacks/StackOfLinkedList.java)
+          - 📁 **trees**
+            - 📄 [AVLSimple](src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java)
+            - 📄 [AVLTree](src/main/java/com/thealgorithms/datastructures/trees/AVLTree.java)
+            - 📄 [BSTFromSortedArray](src/main/java/com/thealgorithms/datastructures/trees/BSTFromSortedArray.java)
+            - 📄 [BSTIterative](src/main/java/com/thealgorithms/datastructures/trees/BSTIterative.java)
+            - 📄 [BSTRecursive](src/main/java/com/thealgorithms/datastructures/trees/BSTRecursive.java)
+            - 📄 [BSTRecursiveGeneric](src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java)
+            - 📄 [BTree](src/main/java/com/thealgorithms/datastructures/trees/BTree.java)
+            - 📄 [BinaryTree](src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java)
+            - 📄 [BoundaryTraversal](src/main/java/com/thealgorithms/datastructures/trees/BoundaryTraversal.java)
+            - 📄 [CeilInBinarySearchTree](src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java)
+            - 📄 [CheckBinaryTreeIsValidBST](src/main/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBST.java)
+            - 📄 [CheckIfBinaryTreeBalanced](src/main/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalanced.java)
+            - 📄 [CheckTreeIsSymmetric](src/main/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetric.java)
+            - 📄 [CreateBinaryTreeFromInorderPreorder](src/main/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorder.java)
+            - 📄 [FenwickTree](src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java)
+            - 📄 [GenericTree](src/main/java/com/thealgorithms/datastructures/trees/GenericTree.java)
+            - 📄 [InorderTraversal](src/main/java/com/thealgorithms/datastructures/trees/InorderTraversal.java)
+            - 📄 [KDTree](src/main/java/com/thealgorithms/datastructures/trees/KDTree.java)
+            - 📄 [LCA](src/main/java/com/thealgorithms/datastructures/trees/LCA.java)
+            - 📄 [LazySegmentTree](src/main/java/com/thealgorithms/datastructures/trees/LazySegmentTree.java)
+            - 📄 [LevelOrderTraversal](src/main/java/com/thealgorithms/datastructures/trees/LevelOrderTraversal.java)
+            - 📄 [PostOrderTraversal](src/main/java/com/thealgorithms/datastructures/trees/PostOrderTraversal.java)
+            - 📄 [PreOrderTraversal](src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java)
+            - 📄 [PrintTopViewofTree](src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java)
+            - 📄 [QuadTree](src/main/java/com/thealgorithms/datastructures/trees/QuadTree.java)
+            - 📄 [README](src/main/java/com/thealgorithms/datastructures/trees/README.md)
+            - 📄 [RedBlackBST](src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java)
+            - 📄 [SameTreesCheck](src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java)
+            - 📄 [SegmentTree](src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java)
+            - 📄 [SplayTree](src/main/java/com/thealgorithms/datastructures/trees/SplayTree.java)
+            - 📄 [Treap](src/main/java/com/thealgorithms/datastructures/trees/Treap.java)
+            - 📄 [TreeRandomNode](src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java)
+            - 📄 [Trie](src/main/java/com/thealgorithms/datastructures/trees/Trie.java)
+            - 📄 [VerticalOrderTraversal](src/main/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversal.java)
+            - 📄 [ZigzagTraversal](src/main/java/com/thealgorithms/datastructures/trees/ZigzagTraversal.java)
+            - 📄 [nearestRightKey](src/main/java/com/thealgorithms/datastructures/trees/nearestRightKey.java)
+        - 📁 **devutils**
+          - 📁 **entities**
+            - 📄 [ProcessDetails](src/main/java/com/thealgorithms/devutils/entities/ProcessDetails.java)
+          - 📁 **nodes**
+            - 📄 [LargeTreeNode](src/main/java/com/thealgorithms/devutils/nodes/LargeTreeNode.java)
+            - 📄 [Node](src/main/java/com/thealgorithms/devutils/nodes/Node.java)
+            - 📄 [SimpleNode](src/main/java/com/thealgorithms/devutils/nodes/SimpleNode.java)
+            - 📄 [SimpleTreeNode](src/main/java/com/thealgorithms/devutils/nodes/SimpleTreeNode.java)
+            - 📄 [TreeNode](src/main/java/com/thealgorithms/devutils/nodes/TreeNode.java)
+          - 📁 **searches**
+            - 📄 [MatrixSearchAlgorithm](src/main/java/com/thealgorithms/devutils/searches/MatrixSearchAlgorithm.java)
+            - 📄 [SearchAlgorithm](src/main/java/com/thealgorithms/devutils/searches/SearchAlgorithm.java)
+        - 📁 **divideandconquer**
+          - 📄 [BinaryExponentiation](src/main/java/com/thealgorithms/divideandconquer/BinaryExponentiation.java)
+          - 📄 [ClosestPair](src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java)
+          - 📄 [CountingInversions](src/main/java/com/thealgorithms/divideandconquer/CountingInversions.java)
+          - 📄 [MedianOfTwoSortedArrays](src/main/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArrays.java)
+          - 📄 [SkylineAlgorithm](src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java)
+          - 📄 [StrassenMatrixMultiplication](src/main/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplication.java)
+          - 📄 [TilingProblem](src/main/java/com/thealgorithms/divideandconquer/TilingProblem.java)
+        - 📁 **dynamicprogramming**
+          - 📄 [Abbreviation](src/main/java/com/thealgorithms/dynamicprogramming/Abbreviation.java)
+          - 📄 [AllConstruct](src/main/java/com/thealgorithms/dynamicprogramming/AllConstruct.java)
+          - 📄 [AssignmentUsingBitmask](src/main/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmask.java)
+          - 📄 [BoardPath](src/main/java/com/thealgorithms/dynamicprogramming/BoardPath.java)
+          - 📄 [BoundaryFill](src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java)
+          - 📄 [BruteForceKnapsack](src/main/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsack.java)
+          - 📄 [CatalanNumber](src/main/java/com/thealgorithms/dynamicprogramming/CatalanNumber.java)
+          - 📄 [ClimbingStairs](src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java)
+          - 📄 [CoinChange](src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java)
+          - 📄 [CountFriendsPairing](src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java)
+          - 📄 [DiceThrow](src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java)
+          - 📄 [EditDistance](src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java)
+          - 📄 [EggDropping](src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java)
+          - 📄 [Fibonacci](src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java)
+          - 📄 [KadaneAlgorithm](src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java)
+          - 📄 [Knapsack](src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java)
+          - 📄 [KnapsackMemoization](src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java)
+          - 📄 [LevenshteinDistance](src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java)
+          - 📄 [LongestAlternatingSubsequence](src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java)
+          - 📄 [LongestArithmeticSubsequence](src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java)
+          - 📄 [LongestCommonSubsequence](src/main/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequence.java)
+          - 📄 [LongestIncreasingSubsequence](src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequence.java)
+          - 📄 [LongestIncreasingSubsequenceNLogN](src/main/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogN.java)
+          - 📄 [LongestPalindromicSubsequence](src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java)
+          - 📄 [LongestPalindromicSubstring](src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstring.java)
+          - 📄 [LongestValidParentheses](src/main/java/com/thealgorithms/dynamicprogramming/LongestValidParentheses.java)
+          - 📄 [MatrixChainMultiplication](src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java)
+          - 📄 [MatrixChainRecursiveTopDownMemoisation](src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java)
+          - 📄 [MaximumSumOfNonAdjacentElements](src/main/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElements.java)
+          - 📄 [MinimumPathSum](src/main/java/com/thealgorithms/dynamicprogramming/MinimumPathSum.java)
+          - 📄 [MinimumSumPartition](src/main/java/com/thealgorithms/dynamicprogramming/MinimumSumPartition.java)
+          - 📄 [NewManShanksPrime](src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java)
+          - 📄 [OptimalJobScheduling](src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java)
+          - 📄 [PalindromicPartitioning](src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java)
+          - 📄 [PartitionProblem](src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java)
+          - 📄 [RegexMatching](src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java)
+          - 📄 [RodCutting](src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java)
+          - 📄 [ShortestCommonSupersequenceLength](src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java)
+          - 📄 [SubsetCount](src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java)
+          - 📄 [SubsetSum](src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java)
+          - 📄 [SubsetSumSpaceOptimized](src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java)
+          - 📄 [SumOfSubset](src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java)
+          - 📄 [TreeMatching](src/main/java/com/thealgorithms/dynamicprogramming/TreeMatching.java)
+          - 📄 [Tribonacci](src/main/java/com/thealgorithms/dynamicprogramming/Tribonacci.java)
+          - 📄 [UniquePaths](src/main/java/com/thealgorithms/dynamicprogramming/UniquePaths.java)
+          - 📄 [UniqueSubsequencesCount](src/main/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCount.java)
+          - 📄 [WildcardMatching](src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java)
+          - 📄 [WineProblem](src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java)
+        - 📁 **geometry**
+          - 📄 [BresenhamLine](src/main/java/com/thealgorithms/geometry/BresenhamLine.java)
+          - 📄 [ConvexHull](src/main/java/com/thealgorithms/geometry/ConvexHull.java)
+          - 📄 [GrahamScan](src/main/java/com/thealgorithms/geometry/GrahamScan.java)
+          - 📄 [MidpointCircle](src/main/java/com/thealgorithms/geometry/MidpointCircle.java)
+          - 📄 [MidpointEllipse](src/main/java/com/thealgorithms/geometry/MidpointEllipse.java)
+          - 📄 [Point](src/main/java/com/thealgorithms/geometry/Point.java)
+        - 📁 **graph**
+          - 📄 [ConstrainedShortestPath](src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java)
+          - 📄 [StronglyConnectedComponentOptimized](src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
+          - 📄 [TravelingSalesman](src/main/java/com/thealgorithms/graph/TravelingSalesman.java)
+        - 📁 **greedyalgorithms**
+          - 📄 [ActivitySelection](src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
+          - 📄 [BandwidthAllocation](src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java)
+          - 📄 [BinaryAddition](src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java)
+          - 📄 [CoinChange](src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java)
+          - 📄 [DigitSeparation](src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java)
+          - 📄 [EgyptianFraction](src/main/java/com/thealgorithms/greedyalgorithms/EgyptianFraction.java)
+          - 📄 [FractionalKnapsack](src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
+          - 📄 [GaleShapley](src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java)
+          - 📄 [JobSequencing](src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
+          - 📄 [KCenters](src/main/java/com/thealgorithms/greedyalgorithms/KCenters.java)
+          - 📄 [MergeIntervals](src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java)
+          - 📄 [MinimizingLateness](src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java)
+          - 📄 [MinimumWaitingTime](src/main/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTime.java)
+          - 📄 [OptimalFileMerging](src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java)
+          - 📄 [StockProfitCalculator](src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java)
+        - 📁 **io**
+          - 📄 [BufferedReader](src/main/java/com/thealgorithms/io/BufferedReader.java)
+        - 📁 **lineclipping**
+          - 📄 [CohenSutherland](src/main/java/com/thealgorithms/lineclipping/CohenSutherland.java)
+          - 📄 [LiangBarsky](src/main/java/com/thealgorithms/lineclipping/LiangBarsky.java)
+          - 📁 **utils**
+            - 📄 [Line](src/main/java/com/thealgorithms/lineclipping/utils/Line.java)
+            - 📄 [Point](src/main/java/com/thealgorithms/lineclipping/utils/Point.java)
+        - 📁 **maths**
+          - 📄 [ADTFraction](src/main/java/com/thealgorithms/maths/ADTFraction.java)
+          - 📄 [AbsoluteMax](src/main/java/com/thealgorithms/maths/AbsoluteMax.java)
+          - 📄 [AbsoluteMin](src/main/java/com/thealgorithms/maths/AbsoluteMin.java)
+          - 📄 [AbsoluteValue](src/main/java/com/thealgorithms/maths/AbsoluteValue.java)
+          - 📄 [AliquotSum](src/main/java/com/thealgorithms/maths/AliquotSum.java)
+          - 📄 [AmicableNumber](src/main/java/com/thealgorithms/maths/AmicableNumber.java)
+          - 📄 [Area](src/main/java/com/thealgorithms/maths/Area.java)
+          - 📄 [Armstrong](src/main/java/com/thealgorithms/maths/Armstrong.java)
+          - 📄 [AutoCorrelation](src/main/java/com/thealgorithms/maths/AutoCorrelation.java)
+          - 📄 [AutomorphicNumber](src/main/java/com/thealgorithms/maths/AutomorphicNumber.java)
+          - 📄 [Average](src/main/java/com/thealgorithms/maths/Average.java)
+          - 📄 [BinaryPow](src/main/java/com/thealgorithms/maths/BinaryPow.java)
+          - 📄 [BinomialCoefficient](src/main/java/com/thealgorithms/maths/BinomialCoefficient.java)
+          - 📄 [CatalanNumbers](src/main/java/com/thealgorithms/maths/CatalanNumbers.java)
+          - 📄 [Ceil](src/main/java/com/thealgorithms/maths/Ceil.java)
+          - 📄 [ChineseRemainderTheorem](src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java)
+          - 📄 [CircularConvolutionFFT](src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java)
+          - 📄 [CollatzConjecture](src/main/java/com/thealgorithms/maths/CollatzConjecture.java)
+          - 📄 [Combinations](src/main/java/com/thealgorithms/maths/Combinations.java)
+          - 📄 [Convolution](src/main/java/com/thealgorithms/maths/Convolution.java)
+          - 📄 [ConvolutionFFT](src/main/java/com/thealgorithms/maths/ConvolutionFFT.java)
+          - 📄 [CrossCorrelation](src/main/java/com/thealgorithms/maths/CrossCorrelation.java)
+          - 📄 [DeterminantOfMatrix](src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java)
+          - 📄 [DigitalRoot](src/main/java/com/thealgorithms/maths/DigitalRoot.java)
+          - 📄 [DistanceFormula](src/main/java/com/thealgorithms/maths/DistanceFormula.java)
+          - 📄 [DudeneyNumber](src/main/java/com/thealgorithms/maths/DudeneyNumber.java)
+          - 📄 [EulerMethod](src/main/java/com/thealgorithms/maths/EulerMethod.java)
+          - 📄 [EulersFunction](src/main/java/com/thealgorithms/maths/EulersFunction.java)
+          - 📄 [FFT](src/main/java/com/thealgorithms/maths/FFT.java)
+          - 📄 [FFTBluestein](src/main/java/com/thealgorithms/maths/FFTBluestein.java)
+          - 📄 [Factorial](src/main/java/com/thealgorithms/maths/Factorial.java)
+          - 📄 [FactorialRecursion](src/main/java/com/thealgorithms/maths/FactorialRecursion.java)
+          - 📄 [FastExponentiation](src/main/java/com/thealgorithms/maths/FastExponentiation.java)
+          - 📄 [FastInverseSqrt](src/main/java/com/thealgorithms/maths/FastInverseSqrt.java)
+          - 📄 [FibonacciJavaStreams](src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java)
+          - 📄 [FibonacciLoop](src/main/java/com/thealgorithms/maths/FibonacciLoop.java)
+          - 📄 [FibonacciNumberCheck](src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java)
+          - 📄 [FibonacciNumberGoldenRation](src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java)
+          - 📄 [FindKthNumber](src/main/java/com/thealgorithms/maths/FindKthNumber.java)
+          - 📄 [FindMax](src/main/java/com/thealgorithms/maths/FindMax.java)
+          - 📄 [FindMaxRecursion](src/main/java/com/thealgorithms/maths/FindMaxRecursion.java)
+          - 📄 [FindMin](src/main/java/com/thealgorithms/maths/FindMin.java)
+          - 📄 [FindMinRecursion](src/main/java/com/thealgorithms/maths/FindMinRecursion.java)
+          - 📄 [Floor](src/main/java/com/thealgorithms/maths/Floor.java)
+          - 📄 [FrizzyNumber](src/main/java/com/thealgorithms/maths/FrizzyNumber.java)
+          - 📄 [GCD](src/main/java/com/thealgorithms/maths/GCD.java)
+          - 📄 [GCDRecursion](src/main/java/com/thealgorithms/maths/GCDRecursion.java)
+          - 📄 [Gaussian](src/main/java/com/thealgorithms/maths/Gaussian.java)
+          - 📄 [GenericRoot](src/main/java/com/thealgorithms/maths/GenericRoot.java)
+          - 📄 [GoldbachConjecture](src/main/java/com/thealgorithms/maths/GoldbachConjecture.java)
+          - 📄 [HarshadNumber](src/main/java/com/thealgorithms/maths/HarshadNumber.java)
+          - 📄 [HeronsFormula](src/main/java/com/thealgorithms/maths/HeronsFormula.java)
+          - 📄 [JosephusProblem](src/main/java/com/thealgorithms/maths/JosephusProblem.java)
+          - 📄 [JugglerSequence](src/main/java/com/thealgorithms/maths/JugglerSequence.java)
+          - 📄 [KaprekarNumbers](src/main/java/com/thealgorithms/maths/KaprekarNumbers.java)
+          - 📄 [KaratsubaMultiplication](src/main/java/com/thealgorithms/maths/KaratsubaMultiplication.java)
+          - 📄 [KeithNumber](src/main/java/com/thealgorithms/maths/KeithNumber.java)
+          - 📄 [KrishnamurthyNumber](src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java)
+          - 📄 [LeastCommonMultiple](src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java)
+          - 📄 [LeonardoNumber](src/main/java/com/thealgorithms/maths/LeonardoNumber.java)
+          - 📄 [LinearDiophantineEquationsSolver](src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java)
+          - 📄 [LongDivision](src/main/java/com/thealgorithms/maths/LongDivision.java)
+          - 📄 [LucasSeries](src/main/java/com/thealgorithms/maths/LucasSeries.java)
+          - 📄 [MagicSquare](src/main/java/com/thealgorithms/maths/MagicSquare.java)
+          - 📄 [MathBuilder](src/main/java/com/thealgorithms/maths/MathBuilder.java)
+          - 📄 [MaxValue](src/main/java/com/thealgorithms/maths/MaxValue.java)
+          - 📄 [Means](src/main/java/com/thealgorithms/maths/Means.java)
+          - 📄 [Median](src/main/java/com/thealgorithms/maths/Median.java)
+          - 📄 [MinValue](src/main/java/com/thealgorithms/maths/MinValue.java)
+          - 📄 [Mode](src/main/java/com/thealgorithms/maths/Mode.java)
+          - 📄 [NonRepeatingElement](src/main/java/com/thealgorithms/maths/NonRepeatingElement.java)
+          - 📄 [NthUglyNumber](src/main/java/com/thealgorithms/maths/NthUglyNumber.java)
+          - 📄 [NumberOfDigits](src/main/java/com/thealgorithms/maths/NumberOfDigits.java)
+          - 📄 [PalindromeNumber](src/main/java/com/thealgorithms/maths/PalindromeNumber.java)
+          - 📄 [ParseInteger](src/main/java/com/thealgorithms/maths/ParseInteger.java)
+          - 📄 [PascalTriangle](src/main/java/com/thealgorithms/maths/PascalTriangle.java)
+          - 📄 [PerfectCube](src/main/java/com/thealgorithms/maths/PerfectCube.java)
+          - 📄 [PerfectNumber](src/main/java/com/thealgorithms/maths/PerfectNumber.java)
+          - 📄 [PerfectSquare](src/main/java/com/thealgorithms/maths/PerfectSquare.java)
+          - 📄 [Perimeter](src/main/java/com/thealgorithms/maths/Perimeter.java)
+          - 📄 [PiNilakantha](src/main/java/com/thealgorithms/maths/PiNilakantha.java)
+          - 📄 [PollardRho](src/main/java/com/thealgorithms/maths/PollardRho.java)
+          - 📄 [Pow](src/main/java/com/thealgorithms/maths/Pow.java)
+          - 📄 [PowerOfTwoOrNot](src/main/java/com/thealgorithms/maths/PowerOfTwoOrNot.java)
+          - 📄 [PowerUsingRecursion](src/main/java/com/thealgorithms/maths/PowerUsingRecursion.java)
+          - 📁 **Prime**
+            - 📄 [LiouvilleLambdaFunction](src/main/java/com/thealgorithms/maths/Prime/LiouvilleLambdaFunction.java)
+            - 📄 [MillerRabinPrimalityCheck](src/main/java/com/thealgorithms/maths/Prime/MillerRabinPrimalityCheck.java)
+            - 📄 [MobiusFunction](src/main/java/com/thealgorithms/maths/Prime/MobiusFunction.java)
+            - 📄 [PrimeCheck](src/main/java/com/thealgorithms/maths/Prime/PrimeCheck.java)
+            - 📄 [PrimeFactorization](src/main/java/com/thealgorithms/maths/Prime/PrimeFactorization.java)
+            - 📄 [SquareFreeInteger](src/main/java/com/thealgorithms/maths/Prime/SquareFreeInteger.java)
+          - 📄 [PronicNumber](src/main/java/com/thealgorithms/maths/PronicNumber.java)
+          - 📄 [PythagoreanTriple](src/main/java/com/thealgorithms/maths/PythagoreanTriple.java)
+          - 📄 [QuadraticEquationSolver](src/main/java/com/thealgorithms/maths/QuadraticEquationSolver.java)
+          - 📄 [ReverseNumber](src/main/java/com/thealgorithms/maths/ReverseNumber.java)
+          - 📄 [RomanNumeralUtil](src/main/java/com/thealgorithms/maths/RomanNumeralUtil.java)
+          - 📄 [SecondMinMax](src/main/java/com/thealgorithms/maths/SecondMinMax.java)
+          - 📄 [SieveOfEratosthenes](src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java)
+          - 📄 [SimpsonIntegration](src/main/java/com/thealgorithms/maths/SimpsonIntegration.java)
+          - 📄 [SolovayStrassenPrimalityTest](src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java)
+          - 📄 [SquareRootWithBabylonianMethod](src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java)
+          - 📄 [SquareRootWithNewtonRaphsonMethod](src/main/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonMethod.java)
+          - 📄 [StandardDeviation](src/main/java/com/thealgorithms/maths/StandardDeviation.java)
+          - 📄 [StandardScore](src/main/java/com/thealgorithms/maths/StandardScore.java)
+          - 📄 [StrobogrammaticNumber](src/main/java/com/thealgorithms/maths/StrobogrammaticNumber.java)
+          - 📄 [SumOfArithmeticSeries](src/main/java/com/thealgorithms/maths/SumOfArithmeticSeries.java)
+          - 📄 [SumOfDigits](src/main/java/com/thealgorithms/maths/SumOfDigits.java)
+          - 📄 [SumOfOddNumbers](src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java)
+          - 📄 [SumWithoutArithmeticOperators](src/main/java/com/thealgorithms/maths/SumWithoutArithmeticOperators.java)
+          - 📄 [TrinomialTriangle](src/main/java/com/thealgorithms/maths/TrinomialTriangle.java)
+          - 📄 [TwinPrime](src/main/java/com/thealgorithms/maths/TwinPrime.java)
+          - 📄 [UniformNumbers](src/main/java/com/thealgorithms/maths/UniformNumbers.java)
+          - 📄 [VampireNumber](src/main/java/com/thealgorithms/maths/VampireNumber.java)
+          - 📄 [VectorCrossProduct](src/main/java/com/thealgorithms/maths/VectorCrossProduct.java)
+          - 📄 [Volume](src/main/java/com/thealgorithms/maths/Volume.java)
+        - 📁 **matrix**
+          - 📄 [InverseOfMatrix](src/main/java/com/thealgorithms/matrix/InverseOfMatrix.java)
+          - 📄 [MatrixRank](src/main/java/com/thealgorithms/matrix/MatrixRank.java)
+          - 📄 [MatrixTranspose](src/main/java/com/thealgorithms/matrix/MatrixTranspose.java)
+          - 📄 [MedianOfMatrix](src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java)
+          - 📄 [MirrorOfMatrix](src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java)
+          - 📄 [PrintAMatrixInSpiralOrder](src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java)
+          - 📄 [RotateMatrixBy90Degrees](src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java)
+          - 📄 [SolveSystem](src/main/java/com/thealgorithms/matrix/SolveSystem.java)
+          - 📁 **matrixexponentiation**
+            - 📄 [Fibonacci](src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java)
+          - 📁 **utils**
+            - 📄 [MatrixUtil](src/main/java/com/thealgorithms/matrix/utils/MatrixUtil.java)
+        - 📁 **misc**
+          - 📄 [ColorContrastRatio](src/main/java/com/thealgorithms/misc/ColorContrastRatio.java)
+          - 📄 [MapReduce](src/main/java/com/thealgorithms/misc/MapReduce.java)
+          - 📄 [MedianOfRunningArray](src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java)
+          - 📄 [MedianOfRunningArrayByte](src/main/java/com/thealgorithms/misc/MedianOfRunningArrayByte.java)
+          - 📄 [MedianOfRunningArrayDouble](src/main/java/com/thealgorithms/misc/MedianOfRunningArrayDouble.java)
+          - 📄 [MedianOfRunningArrayFloat](src/main/java/com/thealgorithms/misc/MedianOfRunningArrayFloat.java)
+          - 📄 [MedianOfRunningArrayInteger](src/main/java/com/thealgorithms/misc/MedianOfRunningArrayInteger.java)
+          - 📄 [MedianOfRunningArrayLong](src/main/java/com/thealgorithms/misc/MedianOfRunningArrayLong.java)
+          - 📄 [PalindromePrime](src/main/java/com/thealgorithms/misc/PalindromePrime.java)
+          - 📄 [PalindromeSinglyLinkedList](src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java)
+          - 📄 [RangeInSortedArray](src/main/java/com/thealgorithms/misc/RangeInSortedArray.java)
+          - 📄 [ShuffleArray](src/main/java/com/thealgorithms/misc/ShuffleArray.java)
+          - 📄 [Sparsity](src/main/java/com/thealgorithms/misc/Sparsity.java)
+          - 📄 [ThreeSumProblem](src/main/java/com/thealgorithms/misc/ThreeSumProblem.java)
+          - 📄 [TwoSumProblem](src/main/java/com/thealgorithms/misc/TwoSumProblem.java)
+        - 📁 **others**
+          - 📄 [ArrayLeftRotation](src/main/java/com/thealgorithms/others/ArrayLeftRotation.java)
+          - 📄 [ArrayRightRotation](src/main/java/com/thealgorithms/others/ArrayRightRotation.java)
+          - 📄 [BFPRT](src/main/java/com/thealgorithms/others/BFPRT.java)
+          - 📄 [BankersAlgorithm](src/main/java/com/thealgorithms/others/BankersAlgorithm.java)
+          - 📄 [BoyerMoore](src/main/java/com/thealgorithms/others/BoyerMoore.java)
+          - 📄 [BrianKernighanAlgorithm](src/main/java/com/thealgorithms/others/BrianKernighanAlgorithm.java)
+          - 📄 [CRC16](src/main/java/com/thealgorithms/others/CRC16.java)
+          - 📄 [CRC32](src/main/java/com/thealgorithms/others/CRC32.java)
+          - 📄 [CRCAlgorithm](src/main/java/com/thealgorithms/others/CRCAlgorithm.java)
+          - 📄 [Conway](src/main/java/com/thealgorithms/others/Conway.java)
+          - 📄 [Damm](src/main/java/com/thealgorithms/others/Damm.java)
+          - 📄 [Dijkstra](src/main/java/com/thealgorithms/others/Dijkstra.java)
+          - 📄 [FloydTriangle](src/main/java/com/thealgorithms/others/FloydTriangle.java)
+          - 📄 [GaussLegendre](src/main/java/com/thealgorithms/others/GaussLegendre.java)
+          - 📄 [HappyNumbersSeq](src/main/java/com/thealgorithms/others/HappyNumbersSeq.java)
+          - 📄 [Huffman](src/main/java/com/thealgorithms/others/Huffman.java)
+          - 📄 [Implementing_auto_completing_features_using_trie](src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java)
+          - 📄 [InsertDeleteInArray](src/main/java/com/thealgorithms/others/InsertDeleteInArray.java)
+          - 📄 [KochSnowflake](src/main/java/com/thealgorithms/others/KochSnowflake.java)
+          - 📄 [Krishnamurthy](src/main/java/com/thealgorithms/others/Krishnamurthy.java)
+          - 📄 [LineSweep](src/main/java/com/thealgorithms/others/LineSweep.java)
+          - 📄 [LinearCongruentialGenerator](src/main/java/com/thealgorithms/others/LinearCongruentialGenerator.java)
+          - 📄 [LowestBasePalindrome](src/main/java/com/thealgorithms/others/LowestBasePalindrome.java)
+          - 📄 [Luhn](src/main/java/com/thealgorithms/others/Luhn.java)
+          - 📄 [Mandelbrot](src/main/java/com/thealgorithms/others/Mandelbrot.java)
+          - 📄 [MaximumSlidingWindow](src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java)
+          - 📄 [MaximumSumOfDistinctSubarraysWithLengthK](src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java)
+          - 📄 [MemoryManagementAlgorithms](src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java)
+          - 📄 [MiniMaxAlgorithm](src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java)
+          - 📄 [PageRank](src/main/java/com/thealgorithms/others/PageRank.java)
+          - 📄 [PasswordGen](src/main/java/com/thealgorithms/others/PasswordGen.java)
+          - 📄 [PerlinNoise](src/main/java/com/thealgorithms/others/PerlinNoise.java)
+          - 📄 [PrintAMatrixInSpiralOrder](src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java)
+          - 📄 [QueueUsingTwoStacks](src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java)
+          - 📄 [RemoveDuplicateFromString](src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java)
+          - 📄 [ReverseStackUsingRecursion](src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
+          - 📄 [SkylineProblem](src/main/java/com/thealgorithms/others/SkylineProblem.java)
+          - 📄 [TwoPointers](src/main/java/com/thealgorithms/others/TwoPointers.java)
+          - 📄 [Verhoeff](src/main/java/com/thealgorithms/others/Verhoeff.java)
+          - 📁 **cn**
+            - 📄 [HammingDistance](src/main/java/com/thealgorithms/others/cn/HammingDistance.java)
+        - 📁 **puzzlesandgames**
+          - 📄 [Sudoku](src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java)
+          - 📄 [TowerOfHanoi](src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java)
+          - 📄 [WordBoggle](src/main/java/com/thealgorithms/puzzlesandgames/WordBoggle.java)
+        - 📁 **randomized**
+          - 📄 [KargerMinCut](src/main/java/com/thealgorithms/randomized/KargerMinCut.java)
+          - 📄 [MonteCarloIntegration](src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java)
+          - 📄 [RandomizedQuickSort](src/main/java/com/thealgorithms/randomized/RandomizedQuickSort.java)
+          - 📄 [ReservoirSampling](src/main/java/com/thealgorithms/randomized/ReservoirSampling.java)
+        - 📁 **recursion**
+          - 📄 [FibonacciSeries](src/main/java/com/thealgorithms/recursion/FibonacciSeries.java)
+          - 📄 [GenerateSubsets](src/main/java/com/thealgorithms/recursion/GenerateSubsets.java)
+        - 📁 **scheduling**
+          - 📄 [AgingScheduling](src/main/java/com/thealgorithms/scheduling/AgingScheduling.java)
+          - 📄 [EDFScheduling](src/main/java/com/thealgorithms/scheduling/EDFScheduling.java)
+          - 📄 [FCFSScheduling](src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
+          - 📄 [FairShareScheduling](src/main/java/com/thealgorithms/scheduling/FairShareScheduling.java)
+          - 📄 [GangScheduling](src/main/java/com/thealgorithms/scheduling/GangScheduling.java)
+          - 📄 [HighestResponseRatioNextScheduling](src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
+          - 📄 [JobSchedulingWithDeadline](src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java)
+          - 📄 [LotteryScheduling](src/main/java/com/thealgorithms/scheduling/LotteryScheduling.java)
+          - 📄 [MLFQScheduler](src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java)
+          - 📄 [MultiAgentScheduling](src/main/java/com/thealgorithms/scheduling/MultiAgentScheduling.java)
+          - 📄 [NonPreemptivePriorityScheduling](src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java)
+          - 📄 [PreemptivePriorityScheduling](src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
+          - 📄 [ProportionalFairScheduling](src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java)
+          - 📄 [RRScheduling](src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
+          - 📄 [RandomScheduling](src/main/java/com/thealgorithms/scheduling/RandomScheduling.java)
+          - 📄 [SJFScheduling](src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
+          - 📄 [SRTFScheduling](src/main/java/com/thealgorithms/scheduling/SRTFScheduling.java)
+          - 📄 [SelfAdjustingScheduling](src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java)
+          - 📄 [SlackTimeScheduling](src/main/java/com/thealgorithms/scheduling/SlackTimeScheduling.java)
+          - 📁 **diskscheduling**
+            - 📄 [CircularLookScheduling](src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularLookScheduling.java)
+            - 📄 [CircularScanScheduling](src/main/java/com/thealgorithms/scheduling/diskscheduling/CircularScanScheduling.java)
+            - 📄 [LookScheduling](src/main/java/com/thealgorithms/scheduling/diskscheduling/LookScheduling.java)
+            - 📄 [SSFScheduling](src/main/java/com/thealgorithms/scheduling/diskscheduling/SSFScheduling.java)
+            - 📄 [ScanScheduling](src/main/java/com/thealgorithms/scheduling/diskscheduling/ScanScheduling.java)
+        - 📁 **searches**
+          - 📄 [BM25InvertedIndex](src/main/java/com/thealgorithms/searches/BM25InvertedIndex.java)
+          - 📄 [BinarySearch](src/main/java/com/thealgorithms/searches/BinarySearch.java)
+          - 📄 [BinarySearch2dArray](src/main/java/com/thealgorithms/searches/BinarySearch2dArray.java)
+          - 📄 [BoyerMoore](src/main/java/com/thealgorithms/searches/BoyerMoore.java)
+          - 📄 [BreadthFirstSearch](src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java)
+          - 📄 [DepthFirstSearch](src/main/java/com/thealgorithms/searches/DepthFirstSearch.java)
+          - 📄 [ExponentalSearch](src/main/java/com/thealgorithms/searches/ExponentalSearch.java)
+          - 📄 [FibonacciSearch](src/main/java/com/thealgorithms/searches/FibonacciSearch.java)
+          - 📄 [HowManyTimesRotated](src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java)
+          - 📄 [InterpolationSearch](src/main/java/com/thealgorithms/searches/InterpolationSearch.java)
+          - 📄 [IterativeBinarySearch](src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java)
+          - 📄 [IterativeTernarySearch](src/main/java/com/thealgorithms/searches/IterativeTernarySearch.java)
+          - 📄 [JumpSearch](src/main/java/com/thealgorithms/searches/JumpSearch.java)
+          - 📄 [KMPSearch](src/main/java/com/thealgorithms/searches/KMPSearch.java)
+          - 📄 [LinearSearch](src/main/java/com/thealgorithms/searches/LinearSearch.java)
+          - 📄 [LinearSearchThread](src/main/java/com/thealgorithms/searches/LinearSearchThread.java)
+          - 📄 [LowerBound](src/main/java/com/thealgorithms/searches/LowerBound.java)
+          - 📄 [MonteCarloTreeSearch](src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java)
+          - 📄 [OrderAgnosticBinarySearch](src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java)
+          - 📄 [PerfectBinarySearch](src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java)
+          - 📄 [QuickSelect](src/main/java/com/thealgorithms/searches/QuickSelect.java)
+          - 📄 [RabinKarpAlgorithm](src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java)
+          - 📄 [RandomSearch](src/main/java/com/thealgorithms/searches/RandomSearch.java)
+          - 📄 [RecursiveBinarySearch](src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java)
+          - 📄 [RowColumnWiseSorted2dArrayBinarySearch](src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java)
+          - 📄 [SaddlebackSearch](src/main/java/com/thealgorithms/searches/SaddlebackSearch.java)
+          - 📄 [SearchInARowAndColWiseSortedMatrix](src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java)
+          - 📄 [SortOrderAgnosticBinarySearch](src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java)
+          - 📄 [SquareRootBinarySearch](src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java)
+          - 📄 [TernarySearch](src/main/java/com/thealgorithms/searches/TernarySearch.java)
+          - 📄 [UnionFind](src/main/java/com/thealgorithms/searches/UnionFind.java)
+          - 📄 [UpperBound](src/main/java/com/thealgorithms/searches/UpperBound.java)
+        - 📁 **slidingwindow**
+          - 📄 [LongestSubarrayWithSumLessOrEqualToK](src/main/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToK.java)
+          - 📄 [LongestSubstringWithoutRepeatingCharacters](src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java)
+          - 📄 [MaxSumKSizeSubarray](src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java)
+          - 📄 [MinSumKSizeSubarray](src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java)
+          - 📄 [ShortestCoprimeSegment](src/main/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegment.java)
+        - 📁 **sorts**
+          - 📄 [AdaptiveMergeSort](src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java)
+          - 📄 [BeadSort](src/main/java/com/thealgorithms/sorts/BeadSort.java)
+          - 📄 [BinaryInsertionSort](src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java)
+          - 📄 [BitonicSort](src/main/java/com/thealgorithms/sorts/BitonicSort.java)
+          - 📄 [BogoSort](src/main/java/com/thealgorithms/sorts/BogoSort.java)
+          - 📄 [BubbleSort](src/main/java/com/thealgorithms/sorts/BubbleSort.java)
+          - 📄 [BubbleSortRecursive](src/main/java/com/thealgorithms/sorts/BubbleSortRecursive.java)
+          - 📄 [BucketSort](src/main/java/com/thealgorithms/sorts/BucketSort.java)
+          - 📄 [CircleSort](src/main/java/com/thealgorithms/sorts/CircleSort.java)
+          - 📄 [CocktailShakerSort](src/main/java/com/thealgorithms/sorts/CocktailShakerSort.java)
+          - 📄 [CombSort](src/main/java/com/thealgorithms/sorts/CombSort.java)
+          - 📄 [CountingSort](src/main/java/com/thealgorithms/sorts/CountingSort.java)
+          - 📄 [CycleSort](src/main/java/com/thealgorithms/sorts/CycleSort.java)
+          - 📄 [DarkSort](src/main/java/com/thealgorithms/sorts/DarkSort.java)
+          - 📄 [DualPivotQuickSort](src/main/java/com/thealgorithms/sorts/DualPivotQuickSort.java)
+          - 📄 [DutchNationalFlagSort](src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java)
+          - 📄 [ExchangeSort](src/main/java/com/thealgorithms/sorts/ExchangeSort.java)
+          - 📄 [FlashSort](src/main/java/com/thealgorithms/sorts/FlashSort.java)
+          - 📄 [GnomeSort](src/main/java/com/thealgorithms/sorts/GnomeSort.java)
+          - 📄 [HeapSort](src/main/java/com/thealgorithms/sorts/HeapSort.java)
+          - 📄 [InsertionSort](src/main/java/com/thealgorithms/sorts/InsertionSort.java)
+          - 📄 [IntrospectiveSort](src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java)
+          - 📄 [LinkListSort](src/main/java/com/thealgorithms/sorts/LinkListSort.java)
+          - 📄 [MergeSort](src/main/java/com/thealgorithms/sorts/MergeSort.java)
+          - 📄 [MergeSortNoExtraSpace](src/main/java/com/thealgorithms/sorts/MergeSortNoExtraSpace.java)
+          - 📄 [MergeSortRecursive](src/main/java/com/thealgorithms/sorts/MergeSortRecursive.java)
+          - 📄 [OddEvenSort](src/main/java/com/thealgorithms/sorts/OddEvenSort.java)
+          - 📄 [PancakeSort](src/main/java/com/thealgorithms/sorts/PancakeSort.java)
+          - 📄 [PatienceSort](src/main/java/com/thealgorithms/sorts/PatienceSort.java)
+          - 📄 [PigeonholeSort](src/main/java/com/thealgorithms/sorts/PigeonholeSort.java)
+          - 📄 [QuickSort](src/main/java/com/thealgorithms/sorts/QuickSort.java)
+          - 📄 [RadixSort](src/main/java/com/thealgorithms/sorts/RadixSort.java)
+          - 📄 [SelectionSort](src/main/java/com/thealgorithms/sorts/SelectionSort.java)
+          - 📄 [SelectionSortRecursive](src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java)
+          - 📄 [ShellSort](src/main/java/com/thealgorithms/sorts/ShellSort.java)
+          - 📄 [SimpleSort](src/main/java/com/thealgorithms/sorts/SimpleSort.java)
+          - 📄 [SlowSort](src/main/java/com/thealgorithms/sorts/SlowSort.java)
+          - 📄 [SortAlgorithm](src/main/java/com/thealgorithms/sorts/SortAlgorithm.java)
+          - 📄 [SortUtils](src/main/java/com/thealgorithms/sorts/SortUtils.java)
+          - 📄 [SortUtilsRandomGenerator](src/main/java/com/thealgorithms/sorts/SortUtilsRandomGenerator.java)
+          - 📄 [SpreadSort](src/main/java/com/thealgorithms/sorts/SpreadSort.java)
+          - 📄 [StalinSort](src/main/java/com/thealgorithms/sorts/StalinSort.java)
+          - 📄 [StoogeSort](src/main/java/com/thealgorithms/sorts/StoogeSort.java)
+          - 📄 [StrandSort](src/main/java/com/thealgorithms/sorts/StrandSort.java)
+          - 📄 [SwapSort](src/main/java/com/thealgorithms/sorts/SwapSort.java)
+          - 📄 [TimSort](src/main/java/com/thealgorithms/sorts/TimSort.java)
+          - 📄 [TopologicalSort](src/main/java/com/thealgorithms/sorts/TopologicalSort.java)
+          - 📄 [TreeSort](src/main/java/com/thealgorithms/sorts/TreeSort.java)
+          - 📄 [WaveSort](src/main/java/com/thealgorithms/sorts/WaveSort.java)
+          - 📄 [WiggleSort](src/main/java/com/thealgorithms/sorts/WiggleSort.java)
+        - 📁 **stacks**
+          - 📄 [BalancedBrackets](src/main/java/com/thealgorithms/stacks/BalancedBrackets.java)
+          - 📄 [CelebrityFinder](src/main/java/com/thealgorithms/stacks/CelebrityFinder.java)
+          - 📄 [DecimalToAnyUsingStack](src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java)
+          - 📄 [DuplicateBrackets](src/main/java/com/thealgorithms/stacks/DuplicateBrackets.java)
+          - 📄 [GreatestElementConstantTime](src/main/java/com/thealgorithms/stacks/GreatestElementConstantTime.java)
+          - 📄 [InfixToPostfix](src/main/java/com/thealgorithms/stacks/InfixToPostfix.java)
+          - 📄 [InfixToPrefix](src/main/java/com/thealgorithms/stacks/InfixToPrefix.java)
+          - 📄 [LargestRectangle](src/main/java/com/thealgorithms/stacks/LargestRectangle.java)
+          - 📄 [MaximumMinimumWindow](src/main/java/com/thealgorithms/stacks/MaximumMinimumWindow.java)
+          - 📄 [MinStackUsingSingleStack](src/main/java/com/thealgorithms/stacks/MinStackUsingSingleStack.java)
+          - 📄 [MinStackUsingTwoStacks](src/main/java/com/thealgorithms/stacks/MinStackUsingTwoStacks.java)
+          - 📄 [NextGreaterElement](src/main/java/com/thealgorithms/stacks/NextGreaterElement.java)
+          - 📄 [NextSmallerElement](src/main/java/com/thealgorithms/stacks/NextSmallerElement.java)
+          - 📄 [PalindromeWithStack](src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java)
+          - 📄 [PostfixEvaluator](src/main/java/com/thealgorithms/stacks/PostfixEvaluator.java)
+          - 📄 [PostfixToInfix](src/main/java/com/thealgorithms/stacks/PostfixToInfix.java)
+          - 📄 [PrefixEvaluator](src/main/java/com/thealgorithms/stacks/PrefixEvaluator.java)
+          - 📄 [PrefixToInfix](src/main/java/com/thealgorithms/stacks/PrefixToInfix.java)
+          - 📄 [SmallestElementConstantTime](src/main/java/com/thealgorithms/stacks/SmallestElementConstantTime.java)
+          - 📄 [SortStack](src/main/java/com/thealgorithms/stacks/SortStack.java)
+          - 📄 [StackPostfixNotation](src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
+          - 📄 [StackUsingTwoQueues](src/main/java/com/thealgorithms/stacks/StackUsingTwoQueues.java)
+        - 📁 **strings**
+          - 📄 [AhoCorasick](src/main/java/com/thealgorithms/strings/AhoCorasick.java)
+          - 📄 [Alphabetical](src/main/java/com/thealgorithms/strings/Alphabetical.java)
+          - 📄 [Anagrams](src/main/java/com/thealgorithms/strings/Anagrams.java)
+          - 📄 [CharactersSame](src/main/java/com/thealgorithms/strings/CharactersSame.java)
+          - 📄 [CheckVowels](src/main/java/com/thealgorithms/strings/CheckVowels.java)
+          - 📄 [CountChar](src/main/java/com/thealgorithms/strings/CountChar.java)
+          - 📄 [CountWords](src/main/java/com/thealgorithms/strings/CountWords.java)
+          - 📄 [HammingDistance](src/main/java/com/thealgorithms/strings/HammingDistance.java)
+          - 📄 [HorspoolSearch](src/main/java/com/thealgorithms/strings/HorspoolSearch.java)
+          - 📄 [Isomorphic](src/main/java/com/thealgorithms/strings/Isomorphic.java)
+          - 📄 [KMP](src/main/java/com/thealgorithms/strings/KMP.java)
+          - 📄 [LetterCombinationsOfPhoneNumber](src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java)
+          - 📄 [LongestCommonPrefix](src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java)
+          - 📄 [LongestNonRepetitiveSubstring](src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java)
+          - 📄 [LongestPalindromicSubstring](src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java)
+          - 📄 [Lower](src/main/java/com/thealgorithms/strings/Lower.java)
+          - 📄 [Manacher](src/main/java/com/thealgorithms/strings/Manacher.java)
+          - 📄 [MyAtoi](src/main/java/com/thealgorithms/strings/MyAtoi.java)
+          - 📄 [Palindrome](src/main/java/com/thealgorithms/strings/Palindrome.java)
+          - 📄 [Pangram](src/main/java/com/thealgorithms/strings/Pangram.java)
+          - 📄 [PermuteString](src/main/java/com/thealgorithms/strings/PermuteString.java)
+          - 📄 [RabinKarp](src/main/java/com/thealgorithms/strings/RabinKarp.java)
+          - 📄 [ReturnSubsequence](src/main/java/com/thealgorithms/strings/ReturnSubsequence.java)
+          - 📄 [ReverseString](src/main/java/com/thealgorithms/strings/ReverseString.java)
+          - 📄 [ReverseStringRecursive](src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java)
+          - 📄 [ReverseWordsInString](src/main/java/com/thealgorithms/strings/ReverseWordsInString.java)
+          - 📄 [Rotation](src/main/java/com/thealgorithms/strings/Rotation.java)
+          - 📄 [StringCompression](src/main/java/com/thealgorithms/strings/StringCompression.java)
+          - 📄 [StringMatchFiniteAutomata](src/main/java/com/thealgorithms/strings/StringMatchFiniteAutomata.java)
+          - 📄 [Upper](src/main/java/com/thealgorithms/strings/Upper.java)
+          - 📄 [ValidParentheses](src/main/java/com/thealgorithms/strings/ValidParentheses.java)
+          - 📄 [WordLadder](src/main/java/com/thealgorithms/strings/WordLadder.java)
+          - 📁 **zigZagPattern**
+            - 📄 [README](src/main/java/com/thealgorithms/strings/zigZagPattern/README.md)
+            - 📄 [ZigZagPattern](src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java)
+        - 📁 **tree**
+          - 📄 [HeavyLightDecomposition](src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java)
+- 📁 **test**
+  - 📁 **java**
+    - 📁 **com**
+      - 📁 **thealgorithms**
+        - 📁 **audiofilters**
+          - 📄 [EMAFilterTest](src/test/java/com/thealgorithms/audiofilters/EMAFilterTest.java)
+          - 📄 [IIRFilterTest](src/test/java/com/thealgorithms/audiofilters/IIRFilterTest.java)
+        - 📁 **backtracking**
+          - 📄 [AllPathsFromSourceToTargetTest](src/test/java/com/thealgorithms/backtracking/AllPathsFromSourceToTargetTest.java)
+          - 📄 [ArrayCombinationTest](src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java)
+          - 📄 [CombinationTest](src/test/java/com/thealgorithms/backtracking/CombinationTest.java)
+          - 📄 [CrosswordSolverTest](src/test/java/com/thealgorithms/backtracking/CrosswordSolverTest.java)
+          - 📄 [FloodFillTest](src/test/java/com/thealgorithms/backtracking/FloodFillTest.java)
+          - 📄 [KnightsTourTest](src/test/java/com/thealgorithms/backtracking/KnightsTourTest.java)
+          - 📄 [MColoringTest](src/test/java/com/thealgorithms/backtracking/MColoringTest.java)
+          - 📄 [MazeRecursionTest](src/test/java/com/thealgorithms/backtracking/MazeRecursionTest.java)
+          - 📄 [NQueensTest](src/test/java/com/thealgorithms/backtracking/NQueensTest.java)
+          - 📄 [ParenthesesGeneratorTest](src/test/java/com/thealgorithms/backtracking/ParenthesesGeneratorTest.java)
+          - 📄 [PermutationTest](src/test/java/com/thealgorithms/backtracking/PermutationTest.java)
+          - 📄 [PowerSumTest](src/test/java/com/thealgorithms/backtracking/PowerSumTest.java)
+          - 📄 [SubsequenceFinderTest](src/test/java/com/thealgorithms/backtracking/SubsequenceFinderTest.java)
+          - 📄 [WordPatternMatcherTest](src/test/java/com/thealgorithms/backtracking/WordPatternMatcherTest.java)
+          - 📄 [WordSearchTest](src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
+        - 📁 **bitmanipulation**
+          - 📄 [BcdConversionTest](src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java)
+          - 📄 [BinaryPalindromeCheckTest](src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java)
+          - 📄 [BitSwapTest](src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
+          - 📄 [BooleanAlgebraGatesTest](src/test/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGatesTest.java)
+          - 📄 [ClearLeftmostSetBitTest](src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java)
+          - 📄 [CountLeadingZerosTest](src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java)
+          - 📄 [CountSetBitsTest](src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
+          - 📄 [FindNthBitTest](src/test/java/com/thealgorithms/bitmanipulation/FindNthBitTest.java)
+          - 📄 [FirstDifferentBitTest](src/test/java/com/thealgorithms/bitmanipulation/FirstDifferentBitTest.java)
+          - 📄 [GenerateSubsetsTest](src/test/java/com/thealgorithms/bitmanipulation/GenerateSubsetsTest.java)
+          - 📄 [GrayCodeConversionTest](src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java)
+          - 📄 [HammingDistanceTest](src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java)
+          - 📄 [HigherLowerPowerOfTwoTest](src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java)
+          - 📄 [HighestSetBitTest](src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
+          - 📄 [IndexOfRightMostSetBitTest](src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
+          - 📄 [IsEvenTest](src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
+          - 📄 [IsPowerTwoTest](src/test/java/com/thealgorithms/bitmanipulation/IsPowerTwoTest.java)
+          - 📄 [LowestSetBitTest](src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java)
+          - 📄 [ModuloPowerOfTwoTest](src/test/java/com/thealgorithms/bitmanipulation/ModuloPowerOfTwoTest.java)
+          - 📄 [NextHigherSameBitCountTest](src/test/java/com/thealgorithms/bitmanipulation/NextHigherSameBitCountTest.java)
+          - 📄 [NonRepeatingNumberFinderTest](src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
+          - 📄 [NumberAppearingOddTimesTest](src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java)
+          - 📄 [NumbersDifferentSignsTest](src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
+          - 📄 [OneBitDifferenceTest](src/test/java/com/thealgorithms/bitmanipulation/OneBitDifferenceTest.java)
+          - 📄 [OnesComplementTest](src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java)
+          - 📄 [ParityCheckTest](src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java)
+          - 📄 [ReverseBitsTest](src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
+          - 📄 [SingleBitOperationsTest](src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
+          - 📄 [SingleElementTest](src/test/java/com/thealgorithms/bitmanipulation/SingleElementTest.java)
+          - 📄 [SwapAdjacentBitsTest](src/test/java/com/thealgorithms/bitmanipulation/SwapAdjacentBitsTest.java)
+          - 📄 [TwosComplementTest](src/test/java/com/thealgorithms/bitmanipulation/TwosComplementTest.java)
+          - 📄 [Xs3ConversionTest](src/test/java/com/thealgorithms/bitmanipulation/Xs3ConversionTest.java)
+        - 📁 **ciphers**
+          - 📄 [ADFGVXCipherTest](src/test/java/com/thealgorithms/ciphers/ADFGVXCipherTest.java)
+          - 📄 [AESEncryptionTest](src/test/java/com/thealgorithms/ciphers/AESEncryptionTest.java)
+          - 📄 [AffineCipherTest](src/test/java/com/thealgorithms/ciphers/AffineCipherTest.java)
+          - 📄 [AtbashTest](src/test/java/com/thealgorithms/ciphers/AtbashTest.java)
+          - 📄 [AutokeyTest](src/test/java/com/thealgorithms/ciphers/AutokeyTest.java)
+          - 📄 [BaconianCipherTest](src/test/java/com/thealgorithms/ciphers/BaconianCipherTest.java)
+          - 📄 [BlowfishTest](src/test/java/com/thealgorithms/ciphers/BlowfishTest.java)
+          - 📄 [CaesarTest](src/test/java/com/thealgorithms/ciphers/CaesarTest.java)
+          - 📄 [ColumnarTranspositionCipherTest](src/test/java/com/thealgorithms/ciphers/ColumnarTranspositionCipherTest.java)
+          - 📄 [DESTest](src/test/java/com/thealgorithms/ciphers/DESTest.java)
+          - 📄 [DiffieHellmanTest](src/test/java/com/thealgorithms/ciphers/DiffieHellmanTest.java)
+          - 📄 [ECCTest](src/test/java/com/thealgorithms/ciphers/ECCTest.java)
+          - 📄 [HillCipherTest](src/test/java/com/thealgorithms/ciphers/HillCipherTest.java)
+          - 📄 [MonoAlphabeticTest](src/test/java/com/thealgorithms/ciphers/MonoAlphabeticTest.java)
+          - 📄 [PlayfairTest](src/test/java/com/thealgorithms/ciphers/PlayfairTest.java)
+          - 📄 [PolybiusTest](src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
+          - 📄 [RSATest](src/test/java/com/thealgorithms/ciphers/RSATest.java)
+          - 📄 [RailFenceTest](src/test/java/com/thealgorithms/ciphers/RailFenceTest.java)
+          - 📄 [SimpleSubCipherTest](src/test/java/com/thealgorithms/ciphers/SimpleSubCipherTest.java)
+          - 📄 [VigenereTest](src/test/java/com/thealgorithms/ciphers/VigenereTest.java)
+          - 📄 [XORCipherTest](src/test/java/com/thealgorithms/ciphers/XORCipherTest.java)
+          - 📁 **a5**
+            - 📄 [A5CipherTest](src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java)
+            - 📄 [A5KeyStreamGeneratorTest](src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java)
+            - 📄 [LFSRTest](src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
+        - 📁 **conversions**
+          - 📄 [AffineConverterTest](src/test/java/com/thealgorithms/conversions/AffineConverterTest.java)
+          - 📄 [AnyBaseToDecimalTest](src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java)
+          - 📄 [AnytoAnyTest](src/test/java/com/thealgorithms/conversions/AnytoAnyTest.java)
+          - 📄 [BinaryToDecimalTest](src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java)
+          - 📄 [BinaryToHexadecimalTest](src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java)
+          - 📄 [BinaryToOctalTest](src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java)
+          - 📄 [DecimalToAnyBaseTest](src/test/java/com/thealgorithms/conversions/DecimalToAnyBaseTest.java)
+          - 📄 [DecimalToBinaryTest](src/test/java/com/thealgorithms/conversions/DecimalToBinaryTest.java)
+          - 📄 [DecimalToHexadecimalTest](src/test/java/com/thealgorithms/conversions/DecimalToHexadecimalTest.java)
+          - 📄 [DecimalToOctalTest](src/test/java/com/thealgorithms/conversions/DecimalToOctalTest.java)
+          - 📄 [EndianConverterTest](src/test/java/com/thealgorithms/conversions/EndianConverterTest.java)
+          - 📄 [HexToOctTest](src/test/java/com/thealgorithms/conversions/HexToOctTest.java)
+          - 📄 [HexaDecimalToBinaryTest](src/test/java/com/thealgorithms/conversions/HexaDecimalToBinaryTest.java)
+          - 📄 [HexaDecimalToDecimalTest](src/test/java/com/thealgorithms/conversions/HexaDecimalToDecimalTest.java)
+          - 📄 [IPConverterTest](src/test/java/com/thealgorithms/conversions/IPConverterTest.java)
+          - 📄 [IPv6ConverterTest](src/test/java/com/thealgorithms/conversions/IPv6ConverterTest.java)
+          - 📄 [IntegerToEnglishTest](src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java)
+          - 📄 [IntegerToRomanTest](src/test/java/com/thealgorithms/conversions/IntegerToRomanTest.java)
+          - 📄 [MorseCodeConverterTest](src/test/java/com/thealgorithms/conversions/MorseCodeConverterTest.java)
+          - 📄 [NumberToWordsTest](src/test/java/com/thealgorithms/conversions/NumberToWordsTest.java)
+          - 📄 [OctalToBinaryTest](src/test/java/com/thealgorithms/conversions/OctalToBinaryTest.java)
+          - 📄 [OctalToDecimalTest](src/test/java/com/thealgorithms/conversions/OctalToDecimalTest.java)
+          - 📄 [OctalToHexadecimalTest](src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
+          - 📄 [PhoneticAlphabetConverterTest](src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java)
+          - 📄 [RomanToIntegerTest](src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java)
+          - 📄 [TurkishToLatinConversionTest](src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java)
+          - 📄 [UnitConversionsTest](src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java)
+          - 📄 [UnitsConverterTest](src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java)
+          - 📄 [WordsToNumberTest](src/test/java/com/thealgorithms/conversions/WordsToNumberTest.java)
+        - 📁 **datastructures**
+          - 📁 **bag**
+            - 📄 [BagTest](src/test/java/com/thealgorithms/datastructures/bag/BagTest.java)
+          - 📁 **bloomfilter**
+            - 📄 [BloomFilterTest](src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java)
+          - 📁 **buffers**
+            - 📄 [CircularBufferTest](src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java)
+          - 📁 **caches**
+            - 📄 [LFUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java)
+            - 📄 [LRUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java)
+            - 📄 [MRUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java)
+          - 📁 **crdt**
+            - 📄 [GCounterTest](src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java)
+            - 📄 [GSetTest](src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java)
+            - 📄 [LWWElementSetTest](src/test/java/com/thealgorithms/datastructures/crdt/LWWElementSetTest.java)
+            - 📄 [ORSetTest](src/test/java/com/thealgorithms/datastructures/crdt/ORSetTest.java)
+            - 📄 [PNCounterTest](src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java)
+            - 📄 [TwoPSetTest](src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java)
+          - 📁 **disjointsetunion**
+            - 📄 [DisjointSetUnionTest](src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java)
+          - 📁 **dynamicarray**
+            - 📄 [DynamicArrayTest](src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java)
+          - 📁 **graphs**
+            - 📄 [AStarTest](src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java)
+            - 📄 [BipartiteGraphDFSTest](src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java)
+            - 📄 [BoruvkaAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
+            - 📄 [DijkstraAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java)
+            - 📄 [DijkstraOptimizedAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java)
+            - 📄 [EdmondsBlossomAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java)
+            - 📄 [FloydWarshallTest](src/test/java/com/thealgorithms/datastructures/graphs/FloydWarshallTest.java)
+            - 📄 [FordFulkersonTest](src/test/java/com/thealgorithms/datastructures/graphs/FordFulkersonTest.java)
+            - 📄 [HamiltonianCycleTest](src/test/java/com/thealgorithms/datastructures/graphs/HamiltonianCycleTest.java)
+            - 📄 [JohnsonsAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithmTest.java)
+            - 📄 [KahnsAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithmTest.java)
+            - 📄 [KosarajuTest](src/test/java/com/thealgorithms/datastructures/graphs/KosarajuTest.java)
+            - 📄 [KruskalTest](src/test/java/com/thealgorithms/datastructures/graphs/KruskalTest.java)
+            - 📄 [MatrixGraphsTest](src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java)
+            - 📄 [PrimMSTTest](src/test/java/com/thealgorithms/datastructures/graphs/PrimMSTTest.java)
+            - 📄 [TarjansAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
+            - 📄 [WelshPowellTest](src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java)
+          - 📁 **hashmap**
+            - 📁 **hashing**
+              - 📄 [GenericHashMapUsingArrayListTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayListTest.java)
+              - 📄 [GenericHashMapUsingArrayTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java)
+              - 📄 [HashMapCuckooHashingTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashingTest.java)
+              - 📄 [HashMapTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java)
+              - 📄 [IntersectionTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/IntersectionTest.java)
+              - 📄 [LinearProbingHashMapTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMapTest.java)
+              - 📄 [MajorityElementTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java)
+              - 📄 [MapTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java)
+          - 📁 **heaps**
+            - 📄 [FibonacciHeapTest](src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
+            - 📄 [GenericHeapTest](src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java)
+            - 📄 [HeapElementTest](src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java)
+            - 📄 [KthElementFinderTest](src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java)
+            - 📄 [LeftistHeapTest](src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
+            - 📄 [MaxHeapTest](src/test/java/com/thealgorithms/datastructures/heaps/MaxHeapTest.java)
+            - 📄 [MedianFinderTest](src/test/java/com/thealgorithms/datastructures/heaps/MedianFinderTest.java)
+            - 📄 [MergeKSortedArraysTest](src/test/java/com/thealgorithms/datastructures/heaps/MergeKSortedArraysTest.java)
+            - 📄 [MinHeapTest](src/test/java/com/thealgorithms/datastructures/heaps/MinHeapTest.java)
+            - 📄 [MinPriorityQueueTest](src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java)
+          - 📁 **lists**
+            - 📄 [CircleLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
+            - 📄 [CountSinglyLinkedListRecursionTest](src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java)
+            - 📄 [CreateAndDetectLoopTest](src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java)
+            - 📄 [CursorLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java)
+            - 📄 [MergeKSortedLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java)
+            - 📄 [MergeSortedArrayListTest](src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java)
+            - 📄 [MergeSortedSinglyLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java)
+            - 📄 [QuickSortLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/QuickSortLinkedListTest.java)
+            - 📄 [ReverseKGroupTest](src/test/java/com/thealgorithms/datastructures/lists/ReverseKGroupTest.java)
+            - 📄 [RotateSinglyLinkedListsTest](src/test/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedListsTest.java)
+            - 📄 [SearchSinglyLinkedListRecursionTest](src/test/java/com/thealgorithms/datastructures/lists/SearchSinglyLinkedListRecursionTest.java)
+            - 📄 [SinglyLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java)
+            - 📄 [SkipListTest](src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java)
+            - 📄 [SortedLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java)
+          - 📁 **queues**
+            - 📄 [CircularQueueTest](src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java)
+            - 📄 [DequeTest](src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java)
+            - 📄 [GenericArrayListQueueTest](src/test/java/com/thealgorithms/datastructures/queues/GenericArrayListQueueTest.java)
+            - 📄 [LinkedQueueTest](src/test/java/com/thealgorithms/datastructures/queues/LinkedQueueTest.java)
+            - 📄 [PriorityQueuesTest](src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java)
+            - 📄 [QueueByTwoStacksTest](src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java)
+            - 📄 [QueueTest](src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java)
+            - 📄 [SlidingWindowMaximumTest](src/test/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximumTest.java)
+            - 📄 [TokenBucketTest](src/test/java/com/thealgorithms/datastructures/queues/TokenBucketTest.java)
+          - 📁 **stacks**
+            - 📄 [NodeStackTest](src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java)
+            - 📄 [ReverseStackTest](src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java)
+            - 📄 [StackArrayListTest](src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java)
+            - 📄 [StackArrayTest](src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java)
+            - 📄 [StackOfLinkedListTest](src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java)
+          - 📁 **trees**
+            - 📄 [AVLTreeTest](src/test/java/com/thealgorithms/datastructures/trees/AVLTreeTest.java)
+            - 📄 [BSTFromSortedArrayTest](src/test/java/com/thealgorithms/datastructures/trees/BSTFromSortedArrayTest.java)
+            - 📄 [BSTIterativeTest](src/test/java/com/thealgorithms/datastructures/trees/BSTIterativeTest.java)
+            - 📄 [BSTRecursiveTest](src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveTest.java)
+            - 📄 [BTreeTest](src/test/java/com/thealgorithms/datastructures/trees/BTreeTest.java)
+            - 📄 [BinaryTreeTest](src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java)
+            - 📄 [BoundaryTraversalTest](src/test/java/com/thealgorithms/datastructures/trees/BoundaryTraversalTest.java)
+            - 📄 [CeilInBinarySearchTreeTest](src/test/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTreeTest.java)
+            - 📄 [CheckBinaryTreeIsValidBSTTest](src/test/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBSTTest.java)
+            - 📄 [CheckIfBinaryTreeBalancedTest](src/test/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalancedTest.java)
+            - 📄 [CheckTreeIsSymmetricTest](src/test/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetricTest.java)
+            - 📄 [CreateBinaryTreeFromInorderPreorderTest](src/test/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorderTest.java)
+            - 📄 [InorderTraversalTest](src/test/java/com/thealgorithms/datastructures/trees/InorderTraversalTest.java)
+            - 📄 [KDTreeTest](src/test/java/com/thealgorithms/datastructures/trees/KDTreeTest.java)
+            - 📄 [LazySegmentTreeTest](src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java)
+            - 📄 [LevelOrderTraversalTest](src/test/java/com/thealgorithms/datastructures/trees/LevelOrderTraversalTest.java)
+            - 📄 [PostOrderTraversalTest](src/test/java/com/thealgorithms/datastructures/trees/PostOrderTraversalTest.java)
+            - 📄 [PreOrderTraversalTest](src/test/java/com/thealgorithms/datastructures/trees/PreOrderTraversalTest.java)
+            - 📄 [QuadTreeTest](src/test/java/com/thealgorithms/datastructures/trees/QuadTreeTest.java)
+            - 📄 [SameTreesCheckTest](src/test/java/com/thealgorithms/datastructures/trees/SameTreesCheckTest.java)
+            - 📄 [SplayTreeTest](src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java)
+            - 📄 [TreapTest](src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java)
+            - 📄 [TreeTestUtils](src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java)
+            - 📄 [TrieTest](src/test/java/com/thealgorithms/datastructures/trees/TrieTest.java)
+            - 📄 [VerticalOrderTraversalTest](src/test/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversalTest.java)
+            - 📄 [ZigzagTraversalTest](src/test/java/com/thealgorithms/datastructures/trees/ZigzagTraversalTest.java)
+        - 📁 **divideandconquer**
+          - 📄 [BinaryExponentiationTest](src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java)
+          - 📄 [ClosestPairTest](src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java)
+          - 📄 [CountingInversionsTest](src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java)
+          - 📄 [MedianOfTwoSortedArraysTest](src/test/java/com/thealgorithms/divideandconquer/MedianOfTwoSortedArraysTest.java)
+          - 📄 [SkylineAlgorithmTest](src/test/java/com/thealgorithms/divideandconquer/SkylineAlgorithmTest.java)
+          - 📄 [StrassenMatrixMultiplicationTest](src/test/java/com/thealgorithms/divideandconquer/StrassenMatrixMultiplicationTest.java)
+          - 📄 [TilingProblemTest](src/test/java/com/thealgorithms/divideandconquer/TilingProblemTest.java)
+        - 📁 **dynamicprogramming**
+          - 📄 [AbbreviationTest](src/test/java/com/thealgorithms/dynamicprogramming/AbbreviationTest.java)
+          - 📄 [AllConstructTest](src/test/java/com/thealgorithms/dynamicprogramming/AllConstructTest.java)
+          - 📄 [AssignmentUsingBitmaskTest](src/test/java/com/thealgorithms/dynamicprogramming/AssignmentUsingBitmaskTest.java)
+          - 📄 [BoardPathTest](src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
+          - 📄 [BoundaryFillTest](src/test/java/com/thealgorithms/dynamicprogramming/BoundaryFillTest.java)
+          - 📄 [BruteForceKnapsackTest](src/test/java/com/thealgorithms/dynamicprogramming/BruteForceKnapsackTest.java)
+          - 📄 [CatalanNumberTest](src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java)
+          - 📄 [ClimbStairsTest](src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java)
+          - 📄 [CoinChangeTest](src/test/java/com/thealgorithms/dynamicprogramming/CoinChangeTest.java)
+          - 📄 [CountFriendsPairingTest](src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java)
+          - 📄 [DPTest](src/test/java/com/thealgorithms/dynamicprogramming/DPTest.java)
+          - 📄 [EditDistanceTest](src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java)
+          - 📄 [EggDroppingTest](src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
+          - 📄 [FibonacciTest](src/test/java/com/thealgorithms/dynamicprogramming/FibonacciTest.java)
+          - 📄 [KadaneAlgorithmTest](src/test/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithmTest.java)
+          - 📄 [KnapsackMemoizationTest](src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
+          - 📄 [KnapsackTest](src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
+          - 📄 [LevenshteinDistanceTests](src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
+          - 📄 [LongestAlternatingSubsequenceTest](src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java)
+          - 📄 [LongestArithmeticSubsequenceTest](src/test/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequenceTest.java)
+          - 📄 [LongestCommonSubsequenceTest](src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java)
+          - 📄 [LongestIncreasingSubsequenceNLogNTest](src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceNLogNTest.java)
+          - 📄 [LongestIncreasingSubsequenceTests](src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java)
+          - 📄 [LongestPalindromicSubstringTest](src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubstringTest.java)
+          - 📄 [LongestValidParenthesesTest](src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java)
+          - 📄 [MatrixChainMultiplicationTest](src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplicationTest.java)
+          - 📄 [MatrixChainRecursiveTopDownMemoisationTest](src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisationTest.java)
+          - 📄 [MaximumSumOfNonAdjacentElementsTest](src/test/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElementsTest.java)
+          - 📄 [MinimumPathSumTest](src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java)
+          - 📄 [MinimumSumPartitionTest](src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java)
+          - 📄 [NewManShanksPrimeTest](src/test/java/com/thealgorithms/dynamicprogramming/NewManShanksPrimeTest.java)
+          - 📄 [OptimalJobSchedulingTest](src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
+          - 📄 [PalindromicPartitioningTest](src/test/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioningTest.java)
+          - 📄 [PartitionProblemTest](src/test/java/com/thealgorithms/dynamicprogramming/PartitionProblemTest.java)
+          - 📄 [RegexMatchingTest](src/test/java/com/thealgorithms/dynamicprogramming/RegexMatchingTest.java)
+          - 📄 [RodCuttingTest](src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java)
+          - 📄 [ShortestCommonSupersequenceLengthTest](src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLengthTest.java)
+          - 📄 [SubsetCountTest](src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java)
+          - 📄 [SubsetSumSpaceOptimizedTest](src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimizedTest.java)
+          - 📄 [SubsetSumTest](src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java)
+          - 📄 [SumOfSubsetTest](src/test/java/com/thealgorithms/dynamicprogramming/SumOfSubsetTest.java)
+          - 📄 [TreeMatchingTest](src/test/java/com/thealgorithms/dynamicprogramming/TreeMatchingTest.java)
+          - 📄 [TribonacciTest](src/test/java/com/thealgorithms/dynamicprogramming/TribonacciTest.java)
+          - 📄 [UniquePathsTests](src/test/java/com/thealgorithms/dynamicprogramming/UniquePathsTests.java)
+          - 📄 [UniqueSubsequencesCountTest](src/test/java/com/thealgorithms/dynamicprogramming/UniqueSubsequencesCountTest.java)
+          - 📄 [WildcardMatchingTest](src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java)
+          - 📄 [WineProblemTest](src/test/java/com/thealgorithms/dynamicprogramming/WineProblemTest.java)
+        - 📁 **geometry**
+          - 📄 [BresenhamLineTest](src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java)
+          - 📄 [ConvexHullTest](src/test/java/com/thealgorithms/geometry/ConvexHullTest.java)
+          - 📄 [GrahamScanTest](src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
+          - 📄 [MidpointCircleTest](src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java)
+          - 📄 [MidpointEllipseTest](src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java)
+        - 📁 **graph**
+          - 📄 [ConstrainedShortestPathTest](src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java)
+          - 📄 [StronglyConnectedComponentOptimizedTest](src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)
+          - 📄 [TravelingSalesmanTest](src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java)
+        - 📁 **greedyalgorithms**
+          - 📄 [ActivitySelectionTest](src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
+          - 📄 [BandwidthAllocationTest](src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java)
+          - 📄 [BinaryAdditionTest](src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java)
+          - 📄 [CoinChangeTest](src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java)
+          - 📄 [DigitSeparationTest](src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java)
+          - 📄 [EgyptianFractionTest](src/test/java/com/thealgorithms/greedyalgorithms/EgyptianFractionTest.java)
+          - 📄 [FractionalKnapsackTest](src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
+          - 📄 [GaleShapleyTest](src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java)
+          - 📄 [JobSequencingTest](src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
+          - 📄 [KCentersTest](src/test/java/com/thealgorithms/greedyalgorithms/KCentersTest.java)
+          - 📄 [MergeIntervalsTest](src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java)
+          - 📄 [MinimizingLatenessTest](src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java)
+          - 📄 [MinimumWaitingTimeTest](src/test/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTimeTest.java)
+          - 📄 [OptimalFileMergingTest](src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java)
+          - 📄 [StockProfitCalculatorTest](src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java)
+        - 📁 **io**
+          - 📄 [BufferedReaderTest](src/test/java/com/thealgorithms/io/BufferedReaderTest.java)
+        - 📁 **lineclipping**
+          - 📄 [CohenSutherlandTest](src/test/java/com/thealgorithms/lineclipping/CohenSutherlandTest.java)
+          - 📄 [LiangBarskyTest](src/test/java/com/thealgorithms/lineclipping/LiangBarskyTest.java)
+        - 📁 **maths**
+          - 📄 [ADTFractionTest](src/test/java/com/thealgorithms/maths/ADTFractionTest.java)
+          - 📄 [AbsoluteMaxTest](src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java)
+          - 📄 [AbsoluteMinTest](src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java)
+          - 📄 [AbsoluteValueTest](src/test/java/com/thealgorithms/maths/AbsoluteValueTest.java)
+          - 📄 [AliquotSumTest](src/test/java/com/thealgorithms/maths/AliquotSumTest.java)
+          - 📄 [AmicableNumberTest](src/test/java/com/thealgorithms/maths/AmicableNumberTest.java)
+          - 📄 [AreaTest](src/test/java/com/thealgorithms/maths/AreaTest.java)
+          - 📄 [ArmstrongTest](src/test/java/com/thealgorithms/maths/ArmstrongTest.java)
+          - 📄 [AutoCorrelationTest](src/test/java/com/thealgorithms/maths/AutoCorrelationTest.java)
+          - 📄 [AutomorphicNumberTest](src/test/java/com/thealgorithms/maths/AutomorphicNumberTest.java)
+          - 📄 [AverageTest](src/test/java/com/thealgorithms/maths/AverageTest.java)
+          - 📄 [BinaryPowTest](src/test/java/com/thealgorithms/maths/BinaryPowTest.java)
+          - 📄 [BinomialCoefficientTest](src/test/java/com/thealgorithms/maths/BinomialCoefficientTest.java)
+          - 📄 [CatalanNumbersTest](src/test/java/com/thealgorithms/maths/CatalanNumbersTest.java)
+          - 📄 [CeilTest](src/test/java/com/thealgorithms/maths/CeilTest.java)
+          - 📄 [ChineseRemainderTheoremTest](src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java)
+          - 📄 [CollatzConjectureTest](src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
+          - 📄 [CombinationsTest](src/test/java/com/thealgorithms/maths/CombinationsTest.java)
+          - 📄 [ConvolutionFFTTest](src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java)
+          - 📄 [ConvolutionTest](src/test/java/com/thealgorithms/maths/ConvolutionTest.java)
+          - 📄 [CrossCorrelationTest](src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java)
+          - 📄 [DeterminantOfMatrixTest](src/test/java/com/thealgorithms/maths/DeterminantOfMatrixTest.java)
+          - 📄 [DigitalRootTest](src/test/java/com/thealgorithms/maths/DigitalRootTest.java)
+          - 📄 [DistanceFormulaTest](src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java)
+          - 📄 [DudeneyNumberTest](src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java)
+          - 📄 [EulerMethodTest](src/test/java/com/thealgorithms/maths/EulerMethodTest.java)
+          - 📄 [EulersFunctionTest](src/test/java/com/thealgorithms/maths/EulersFunctionTest.java)
+          - 📄 [FFTTest](src/test/java/com/thealgorithms/maths/FFTTest.java)
+          - 📄 [FactorialRecursionTest](src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java)
+          - 📄 [FactorialTest](src/test/java/com/thealgorithms/maths/FactorialTest.java)
+          - 📄 [FastExponentiationTest](src/test/java/com/thealgorithms/maths/FastExponentiationTest.java)
+          - 📄 [FastInverseSqrtTests](src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java)
+          - 📄 [FibonacciJavaStreamsTest](src/test/java/com/thealgorithms/maths/FibonacciJavaStreamsTest.java)
+          - 📄 [FibonacciLoopTest](src/test/java/com/thealgorithms/maths/FibonacciLoopTest.java)
+          - 📄 [FibonacciNumberCheckTest](src/test/java/com/thealgorithms/maths/FibonacciNumberCheckTest.java)
+          - 📄 [FibonacciNumberGoldenRationTest](src/test/java/com/thealgorithms/maths/FibonacciNumberGoldenRationTest.java)
+          - 📄 [FindKthNumberTest](src/test/java/com/thealgorithms/maths/FindKthNumberTest.java)
+          - 📄 [FindMaxRecursionTest](src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java)
+          - 📄 [FindMaxTest](src/test/java/com/thealgorithms/maths/FindMaxTest.java)
+          - 📄 [FindMinRecursionTest](src/test/java/com/thealgorithms/maths/FindMinRecursionTest.java)
+          - 📄 [FindMinTest](src/test/java/com/thealgorithms/maths/FindMinTest.java)
+          - 📄 [FloorTest](src/test/java/com/thealgorithms/maths/FloorTest.java)
+          - 📄 [FrizzyNumberTest](src/test/java/com/thealgorithms/maths/FrizzyNumberTest.java)
+          - 📄 [GCDRecursionTest](src/test/java/com/thealgorithms/maths/GCDRecursionTest.java)
+          - 📄 [GCDTest](src/test/java/com/thealgorithms/maths/GCDTest.java)
+          - 📄 [GaussianTest](src/test/java/com/thealgorithms/maths/GaussianTest.java)
+          - 📄 [GenericRootTest](src/test/java/com/thealgorithms/maths/GenericRootTest.java)
+          - 📄 [GoldbachConjectureTest](src/test/java/com/thealgorithms/maths/GoldbachConjectureTest.java)
+          - 📄 [HarshadNumberTest](src/test/java/com/thealgorithms/maths/HarshadNumberTest.java)
+          - 📄 [HeronsFormulaTest](src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java)
+          - 📄 [JosephusProblemTest](src/test/java/com/thealgorithms/maths/JosephusProblemTest.java)
+          - 📄 [KaprekarNumbersTest](src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java)
+          - 📄 [KaratsubaMultiplicationTest](src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java)
+          - 📄 [KrishnamurthyNumberTest](src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java)
+          - 📄 [LeastCommonMultipleTest](src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java)
+          - 📄 [LeonardoNumberTest](src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java)
+          - 📄 [LongDivisionTest](src/test/java/com/thealgorithms/maths/LongDivisionTest.java)
+          - 📄 [LucasSeriesTest](src/test/java/com/thealgorithms/maths/LucasSeriesTest.java)
+          - 📄 [MathBuilderTest](src/test/java/com/thealgorithms/maths/MathBuilderTest.java)
+          - 📄 [MaxValueTest](src/test/java/com/thealgorithms/maths/MaxValueTest.java)
+          - 📄 [MeansTest](src/test/java/com/thealgorithms/maths/MeansTest.java)
+          - 📄 [MedianTest](src/test/java/com/thealgorithms/maths/MedianTest.java)
+          - 📄 [MinValueTest](src/test/java/com/thealgorithms/maths/MinValueTest.java)
+          - 📄 [ModeTest](src/test/java/com/thealgorithms/maths/ModeTest.java)
+          - 📄 [NonRepeatingElementTest](src/test/java/com/thealgorithms/maths/NonRepeatingElementTest.java)
+          - 📄 [NthUglyNumberTest](src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java)
+          - 📄 [NumberOfDigitsTest](src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java)
+          - 📄 [PalindromeNumberTest](src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java)
+          - 📄 [ParseIntegerTest](src/test/java/com/thealgorithms/maths/ParseIntegerTest.java)
+          - 📄 [PascalTriangleTest](src/test/java/com/thealgorithms/maths/PascalTriangleTest.java)
+          - 📄 [PerfectCubeTest](src/test/java/com/thealgorithms/maths/PerfectCubeTest.java)
+          - 📄 [PerfectNumberTest](src/test/java/com/thealgorithms/maths/PerfectNumberTest.java)
+          - 📄 [PerfectSquareTest](src/test/java/com/thealgorithms/maths/PerfectSquareTest.java)
+          - 📄 [PerimeterTest](src/test/java/com/thealgorithms/maths/PerimeterTest.java)
+          - 📄 [PollardRhoTest](src/test/java/com/thealgorithms/maths/PollardRhoTest.java)
+          - 📄 [PowTest](src/test/java/com/thealgorithms/maths/PowTest.java)
+          - 📄 [PowerOfTwoOrNotTest](src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java)
+          - 📄 [PowerUsingRecursionTest](src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java)
+          - 📄 [PronicNumberTest](src/test/java/com/thealgorithms/maths/PronicNumberTest.java)
+          - 📄 [PythagoreanTripleTest](src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java)
+          - 📄 [QuadraticEquationSolverTest](src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java)
+          - 📄 [ReverseNumberTest](src/test/java/com/thealgorithms/maths/ReverseNumberTest.java)
+          - 📄 [SecondMinMaxTest](src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java)
+          - 📄 [SieveOfEratosthenesTest](src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java)
+          - 📄 [SolovayStrassenPrimalityTestTest](src/test/java/com/thealgorithms/maths/SolovayStrassenPrimalityTestTest.java)
+          - 📄 [SquareFreeIntegerTest](src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java)
+          - 📄 [SquareRootWithNewtonRaphsonTestMethod](src/test/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonTestMethod.java)
+          - 📄 [SquareRootwithBabylonianMethodTest](src/test/java/com/thealgorithms/maths/SquareRootwithBabylonianMethodTest.java)
+          - 📄 [StandardDeviationTest](src/test/java/com/thealgorithms/maths/StandardDeviationTest.java)
+          - 📄 [StandardScoreTest](src/test/java/com/thealgorithms/maths/StandardScoreTest.java)
+          - 📄 [StrobogrammaticNumberTest](src/test/java/com/thealgorithms/maths/StrobogrammaticNumberTest.java)
+          - 📄 [SumOfArithmeticSeriesTest](src/test/java/com/thealgorithms/maths/SumOfArithmeticSeriesTest.java)
+          - 📄 [SumOfDigitsTest](src/test/java/com/thealgorithms/maths/SumOfDigitsTest.java)
+          - 📄 [SumOfOddNumbersTest](src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java)
+          - 📄 [SumWithoutArithmeticOperatorsTest](src/test/java/com/thealgorithms/maths/SumWithoutArithmeticOperatorsTest.java)
+          - 📄 [TestArmstrong](src/test/java/com/thealgorithms/maths/TestArmstrong.java)
+          - 📄 [TwinPrimeTest](src/test/java/com/thealgorithms/maths/TwinPrimeTest.java)
+          - 📄 [UniformNumbersTest](src/test/java/com/thealgorithms/maths/UniformNumbersTest.java)
+          - 📄 [VampireNumberTest](src/test/java/com/thealgorithms/maths/VampireNumberTest.java)
+          - 📄 [VolumeTest](src/test/java/com/thealgorithms/maths/VolumeTest.java)
+          - 📁 **prime**
+            - 📄 [LiouvilleLambdaFunctionTest](src/test/java/com/thealgorithms/maths/prime/LiouvilleLambdaFunctionTest.java)
+            - 📄 [MillerRabinPrimalityCheckTest](src/test/java/com/thealgorithms/maths/prime/MillerRabinPrimalityCheckTest.java)
+            - 📄 [MobiusFunctionTest](src/test/java/com/thealgorithms/maths/prime/MobiusFunctionTest.java)
+            - 📄 [PrimeCheckTest](src/test/java/com/thealgorithms/maths/prime/PrimeCheckTest.java)
+            - 📄 [PrimeFactorizationTest](src/test/java/com/thealgorithms/maths/prime/PrimeFactorizationTest.java)
+        - 📁 **matrix**
+          - 📄 [InverseOfMatrixTest](src/test/java/com/thealgorithms/matrix/InverseOfMatrixTest.java)
+          - 📄 [MatrixRankTest](src/test/java/com/thealgorithms/matrix/MatrixRankTest.java)
+          - 📄 [MatrixTransposeTest](src/test/java/com/thealgorithms/matrix/MatrixTransposeTest.java)
+          - 📄 [MatrixUtilTest](src/test/java/com/thealgorithms/matrix/MatrixUtilTest.java)
+          - 📄 [MedianOfMatrixTest](src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java)
+          - 📄 [MirrorOfMatrixTest](src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java)
+          - 📄 [SolveSystemTest](src/test/java/com/thealgorithms/matrix/SolveSystemTest.java)
+          - 📄 [TestPrintMatrixInSpiralOrder](src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java)
+        - 📁 **misc**
+          - 📄 [ColorContrastRatioTest](src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java)
+          - 📄 [MapReduceTest](src/test/java/com/thealgorithms/misc/MapReduceTest.java)
+          - 📄 [MedianOfRunningArrayTest](src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java)
+          - 📄 [PalindromePrimeTest](src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java)
+          - 📄 [PalindromeSinglyLinkedListTest](src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java)
+          - 📄 [RangeInSortedArrayTest](src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java)
+          - 📄 [ShuffleArrayTest](src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java)
+          - 📄 [SparsityTest](src/test/java/com/thealgorithms/misc/SparsityTest.java)
+          - 📄 [ThreeSumProblemTest](src/test/java/com/thealgorithms/misc/ThreeSumProblemTest.java)
+          - 📄 [TwoSumProblemTest](src/test/java/com/thealgorithms/misc/TwoSumProblemTest.java)
+        - 📁 **others**
+          - 📄 [ArrayLeftRotationTest](src/test/java/com/thealgorithms/others/ArrayLeftRotationTest.java)
+          - 📄 [ArrayRightRotationTest](src/test/java/com/thealgorithms/others/ArrayRightRotationTest.java)
+          - 📄 [BFPRTTest](src/test/java/com/thealgorithms/others/BFPRTTest.java)
+          - 📄 [BestFitCPUTest](src/test/java/com/thealgorithms/others/BestFitCPUTest.java)
+          - 📄 [BoyerMooreTest](src/test/java/com/thealgorithms/others/BoyerMooreTest.java)
+          - 📄 [CRC16Test](src/test/java/com/thealgorithms/others/CRC16Test.java)
+          - 📄 [CRCAlgorithmTest](src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java)
+          - 📄 [ConwayTest](src/test/java/com/thealgorithms/others/ConwayTest.java)
+          - 📄 [CountFriendsPairingTest](src/test/java/com/thealgorithms/others/CountFriendsPairingTest.java)
+          - 📄 [FirstFitCPUTest](src/test/java/com/thealgorithms/others/FirstFitCPUTest.java)
+          - 📄 [FloydTriangleTest](src/test/java/com/thealgorithms/others/FloydTriangleTest.java)
+          - 📄 [KadaneAlogrithmTest](src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java)
+          - 📄 [LineSweepTest](src/test/java/com/thealgorithms/others/LineSweepTest.java)
+          - 📄 [LinkListSortTest](src/test/java/com/thealgorithms/others/LinkListSortTest.java)
+          - 📄 [LowestBasePalindromeTest](src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java)
+          - 📄 [MaximumSlidingWindowTest](src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java)
+          - 📄 [MaximumSumOfDistinctSubarraysWithLengthKTest](src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java)
+          - 📄 [NewManShanksPrimeTest](src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java)
+          - 📄 [NextFitTest](src/test/java/com/thealgorithms/others/NextFitTest.java)
+          - 📄 [PasswordGenTest](src/test/java/com/thealgorithms/others/PasswordGenTest.java)
+          - 📄 [QueueUsingTwoStacksTest](src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java)
+          - 📄 [RemoveDuplicateFromStringTest](src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java)
+          - 📄 [ReverseStackUsingRecursionTest](src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
+          - 📄 [SkylineProblemTest](src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
+          - 📄 [TestPrintMatrixInSpiralOrder](src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
+          - 📄 [TwoPointersTest](src/test/java/com/thealgorithms/others/TwoPointersTest.java)
+          - 📄 [WorstFitCPUTest](src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
+          - 📁 **cn**
+            - 📄 [HammingDistanceTest](src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java)
+        - 📁 **puzzlesandgames**
+          - 📄 [SudokuTest](src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java)
+          - 📄 [TowerOfHanoiTest](src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java)
+          - 📄 [WordBoggleTest](src/test/java/com/thealgorithms/puzzlesandgames/WordBoggleTest.java)
+        - 📁 **randomized**
+          - 📄 [KargerMinCutTest](src/test/java/com/thealgorithms/randomized/KargerMinCutTest.java)
+          - 📄 [MonteCarloIntegrationTest](src/test/java/com/thealgorithms/randomized/MonteCarloIntegrationTest.java)
+          - 📄 [RandomizedQuickSortTest](src/test/java/com/thealgorithms/randomized/RandomizedQuickSortTest.java)
+          - 📄 [ReservoirSamplingTest](src/test/java/com/thealgorithms/randomized/ReservoirSamplingTest.java)
+        - 📁 **recursion**
+          - 📄 [FibonacciSeriesTest](src/test/java/com/thealgorithms/recursion/FibonacciSeriesTest.java)
+          - 📄 [GenerateSubsetsTest](src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java)
+        - 📁 **scheduling**
+          - 📄 [AgingSchedulingTest](src/test/java/com/thealgorithms/scheduling/AgingSchedulingTest.java)
+          - 📄 [EDFSchedulingTest](src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java)
+          - 📄 [FCFSSchedulingTest](src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
+          - 📄 [FairShareSchedulingTest](src/test/java/com/thealgorithms/scheduling/FairShareSchedulingTest.java)
+          - 📄 [GangSchedulingTest](src/test/java/com/thealgorithms/scheduling/GangSchedulingTest.java)
+          - 📄 [HighestResponseRatioNextSchedulingTest](src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
+          - 📄 [JobSchedulingWithDeadlineTest](src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java)
+          - 📄 [LotterySchedulingTest](src/test/java/com/thealgorithms/scheduling/LotterySchedulingTest.java)
+          - 📄 [MLFQSchedulerTest](src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java)
+          - 📄 [MultiAgentSchedulingTest](src/test/java/com/thealgorithms/scheduling/MultiAgentSchedulingTest.java)
+          - 📄 [NonPreemptivePrioritySchedulingTest](src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java)
+          - 📄 [PreemptivePrioritySchedulingTest](src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
+          - 📄 [ProportionalFairSchedulingTest](src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java)
+          - 📄 [RRSchedulingTest](src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
+          - 📄 [RandomSchedulingTest](src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java)
+          - 📄 [SJFSchedulingTest](src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)
+          - 📄 [SRTFSchedulingTest](src/test/java/com/thealgorithms/scheduling/SRTFSchedulingTest.java)
+          - 📄 [SelfAdjustingSchedulingTest](src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java)
+          - 📄 [SlackTimeSchedulingTest](src/test/java/com/thealgorithms/scheduling/SlackTimeSchedulingTest.java)
+          - 📁 **diskscheduling**
+            - 📄 [CircularLookSchedulingTest](src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularLookSchedulingTest.java)
+            - 📄 [CircularScanSchedulingTest](src/test/java/com/thealgorithms/scheduling/diskscheduling/CircularScanSchedulingTest.java)
+            - 📄 [LookSchedulingTest](src/test/java/com/thealgorithms/scheduling/diskscheduling/LookSchedulingTest.java)
+            - 📄 [SSFSchedulingTest](src/test/java/com/thealgorithms/scheduling/diskscheduling/SSFSchedulingTest.java)
+            - 📄 [ScanSchedulingTest](src/test/java/com/thealgorithms/scheduling/diskscheduling/ScanSchedulingTest.java)
+        - 📁 **searches**
+          - 📄 [BM25InvertedIndexTest](src/test/java/com/thealgorithms/searches/BM25InvertedIndexTest.java)
+          - 📄 [BinarySearch2dArrayTest](src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java)
+          - 📄 [BinarySearchTest](src/test/java/com/thealgorithms/searches/BinarySearchTest.java)
+          - 📄 [BoyerMooreTest](src/test/java/com/thealgorithms/searches/BoyerMooreTest.java)
+          - 📄 [BreadthFirstSearchTest](src/test/java/com/thealgorithms/searches/BreadthFirstSearchTest.java)
+          - 📄 [DepthFirstSearchTest](src/test/java/com/thealgorithms/searches/DepthFirstSearchTest.java)
+          - 📄 [ExponentialSearchTest](src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java)
+          - 📄 [FibonacciSearchTest](src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java)
+          - 📄 [HowManyTimesRotatedTest](src/test/java/com/thealgorithms/searches/HowManyTimesRotatedTest.java)
+          - 📄 [InterpolationSearchTest](src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java)
+          - 📄 [IterativeBinarySearchTest](src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java)
+          - 📄 [IterativeTernarySearchTest](src/test/java/com/thealgorithms/searches/IterativeTernarySearchTest.java)
+          - 📄 [JumpSearchTest](src/test/java/com/thealgorithms/searches/JumpSearchTest.java)
+          - 📄 [KMPSearchTest](src/test/java/com/thealgorithms/searches/KMPSearchTest.java)
+          - 📄 [LinearSearchTest](src/test/java/com/thealgorithms/searches/LinearSearchTest.java)
+          - 📄 [LinearSearchThreadTest](src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java)
+          - 📄 [LowerBoundTest](src/test/java/com/thealgorithms/searches/LowerBoundTest.java)
+          - 📄 [MonteCarloTreeSearchTest](src/test/java/com/thealgorithms/searches/MonteCarloTreeSearchTest.java)
+          - 📄 [OrderAgnosticBinarySearchTest](src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
+          - 📄 [PerfectBinarySearchTest](src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
+          - 📄 [QuickSelectTest](src/test/java/com/thealgorithms/searches/QuickSelectTest.java)
+          - 📄 [RabinKarpAlgorithmTest](src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java)
+          - 📄 [RandomSearchTest](src/test/java/com/thealgorithms/searches/RandomSearchTest.java)
+          - 📄 [RecursiveBinarySearchTest](src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java)
+          - 📄 [RowColumnWiseSorted2dArrayBinarySearchTest](src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java)
+          - 📄 [SaddlebackSearchTest](src/test/java/com/thealgorithms/searches/SaddlebackSearchTest.java)
+          - 📄 [SearchInARowAndColWiseSortedMatrixTest](src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java)
+          - 📄 [SortOrderAgnosticBinarySearchTest](src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
+          - 📄 [SquareRootBinarySearchTest](src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java)
+          - 📄 [TernarySearchTest](src/test/java/com/thealgorithms/searches/TernarySearchTest.java)
+          - 📄 [TestSearchInARowAndColWiseSortedMatrix](src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
+          - 📄 [UnionFindTest](src/test/java/com/thealgorithms/searches/UnionFindTest.java)
+          - 📄 [UpperBoundTest](src/test/java/com/thealgorithms/searches/UpperBoundTest.java)
+        - 📁 **slidingwindow**
+          - 📄 [LongestSubarrayWithSumLessOrEqualToKTest](src/test/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToKTest.java)
+          - 📄 [LongestSubstringWithoutRepeatingCharactersTest](src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java)
+          - 📄 [MaxSumKSizeSubarrayTest](src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java)
+          - 📄 [MinSumKSizeSubarrayTest](src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java)
+          - 📄 [ShortestCoprimeSegmentTest](src/test/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegmentTest.java)
+        - 📁 **sorts**
+          - 📄 [AdaptiveMergeSortTest](src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java)
+          - 📄 [BeadSortTest](src/test/java/com/thealgorithms/sorts/BeadSortTest.java)
+          - 📄 [BinaryInsertionSortTest](src/test/java/com/thealgorithms/sorts/BinaryInsertionSortTest.java)
+          - 📄 [BitonicSortTest](src/test/java/com/thealgorithms/sorts/BitonicSortTest.java)
+          - 📄 [BogoSortTest](src/test/java/com/thealgorithms/sorts/BogoSortTest.java)
+          - 📄 [BubbleSortRecursiveTest](src/test/java/com/thealgorithms/sorts/BubbleSortRecursiveTest.java)
+          - 📄 [BubbleSortTest](src/test/java/com/thealgorithms/sorts/BubbleSortTest.java)
+          - 📄 [BucketSortTest](src/test/java/com/thealgorithms/sorts/BucketSortTest.java)
+          - 📄 [CircleSortTest](src/test/java/com/thealgorithms/sorts/CircleSortTest.java)
+          - 📄 [CocktailShakerSortTest](src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java)
+          - 📄 [CombSortTest](src/test/java/com/thealgorithms/sorts/CombSortTest.java)
+          - 📄 [CountingSortTest](src/test/java/com/thealgorithms/sorts/CountingSortTest.java)
+          - 📄 [CycleSortTest](src/test/java/com/thealgorithms/sorts/CycleSortTest.java)
+          - 📄 [DarkSortTest](src/test/java/com/thealgorithms/sorts/DarkSortTest.java)
+          - 📄 [DualPivotQuickSortTest](src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java)
+          - 📄 [DutchNationalFlagSortTest](src/test/java/com/thealgorithms/sorts/DutchNationalFlagSortTest.java)
+          - 📄 [ExchangeSortTest](src/test/java/com/thealgorithms/sorts/ExchangeSortTest.java)
+          - 📄 [FlashSortTest](src/test/java/com/thealgorithms/sorts/FlashSortTest.java)
+          - 📄 [GnomeSortTest](src/test/java/com/thealgorithms/sorts/GnomeSortTest.java)
+          - 📄 [HeapSortTest](src/test/java/com/thealgorithms/sorts/HeapSortTest.java)
+          - 📄 [InsertionSortTest](src/test/java/com/thealgorithms/sorts/InsertionSortTest.java)
+          - 📄 [IntrospectiveSortTest](src/test/java/com/thealgorithms/sorts/IntrospectiveSortTest.java)
+          - 📄 [MergeSortNoExtraSpaceTest](src/test/java/com/thealgorithms/sorts/MergeSortNoExtraSpaceTest.java)
+          - 📄 [MergeSortRecursiveTest](src/test/java/com/thealgorithms/sorts/MergeSortRecursiveTest.java)
+          - 📄 [MergeSortTest](src/test/java/com/thealgorithms/sorts/MergeSortTest.java)
+          - 📄 [OddEvenSortTest](src/test/java/com/thealgorithms/sorts/OddEvenSortTest.java)
+          - 📄 [PancakeSortTest](src/test/java/com/thealgorithms/sorts/PancakeSortTest.java)
+          - 📄 [PatienceSortTest](src/test/java/com/thealgorithms/sorts/PatienceSortTest.java)
+          - 📄 [PigeonholeSortTest](src/test/java/com/thealgorithms/sorts/PigeonholeSortTest.java)
+          - 📄 [QuickSortTest](src/test/java/com/thealgorithms/sorts/QuickSortTest.java)
+          - 📄 [RadixSortTest](src/test/java/com/thealgorithms/sorts/RadixSortTest.java)
+          - 📄 [SelectionSortRecursiveTest](src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java)
+          - 📄 [SelectionSortTest](src/test/java/com/thealgorithms/sorts/SelectionSortTest.java)
+          - 📄 [ShellSortTest](src/test/java/com/thealgorithms/sorts/ShellSortTest.java)
+          - 📄 [SimpleSortTest](src/test/java/com/thealgorithms/sorts/SimpleSortTest.java)
+          - 📄 [SlowSortTest](src/test/java/com/thealgorithms/sorts/SlowSortTest.java)
+          - 📄 [SortUtilsRandomGeneratorTest](src/test/java/com/thealgorithms/sorts/SortUtilsRandomGeneratorTest.java)
+          - 📄 [SortUtilsTest](src/test/java/com/thealgorithms/sorts/SortUtilsTest.java)
+          - 📄 [SortingAlgorithmTest](src/test/java/com/thealgorithms/sorts/SortingAlgorithmTest.java)
+          - 📄 [SpreadSortTest](src/test/java/com/thealgorithms/sorts/SpreadSortTest.java)
+          - 📄 [StalinSortTest](src/test/java/com/thealgorithms/sorts/StalinSortTest.java)
+          - 📄 [StoogeSortTest](src/test/java/com/thealgorithms/sorts/StoogeSortTest.java)
+          - 📄 [StrandSortTest](src/test/java/com/thealgorithms/sorts/StrandSortTest.java)
+          - 📄 [SwapSortTest](src/test/java/com/thealgorithms/sorts/SwapSortTest.java)
+          - 📄 [TimSortTest](src/test/java/com/thealgorithms/sorts/TimSortTest.java)
+          - 📄 [TopologicalSortTest](src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java)
+          - 📄 [TreeSortTest](src/test/java/com/thealgorithms/sorts/TreeSortTest.java)
+          - 📄 [WaveSortTest](src/test/java/com/thealgorithms/sorts/WaveSortTest.java)
+          - 📄 [WiggleSortTest](src/test/java/com/thealgorithms/sorts/WiggleSortTest.java)
+        - 📁 **stacks**
+          - 📄 [BalancedBracketsTest](src/test/java/com/thealgorithms/stacks/BalancedBracketsTest.java)
+          - 📄 [CelebrityFinderTest](src/test/java/com/thealgorithms/stacks/CelebrityFinderTest.java)
+          - 📄 [DecimalToAnyUsingStackTest](src/test/java/com/thealgorithms/stacks/DecimalToAnyUsingStackTest.java)
+          - 📄 [DuplicateBracketsTest](src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java)
+          - 📄 [GreatestElementConstantTimeTest](src/test/java/com/thealgorithms/stacks/GreatestElementConstantTimeTest.java)
+          - 📄 [InfixToPostfixTest](src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java)
+          - 📄 [InfixToPrefixTest](src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java)
+          - 📄 [LargestRectangleTest](src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java)
+          - 📄 [MinStackUsingSingleStackTest](src/test/java/com/thealgorithms/stacks/MinStackUsingSingleStackTest.java)
+          - 📄 [MinStackUsingTwoStacksTest](src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java)
+          - 📄 [NextGreaterElementTest](src/test/java/com/thealgorithms/stacks/NextGreaterElementTest.java)
+          - 📄 [NextSmallerElementTest](src/test/java/com/thealgorithms/stacks/NextSmallerElementTest.java)
+          - 📄 [PalindromeWithStackTest](src/test/java/com/thealgorithms/stacks/PalindromeWithStackTest.java)
+          - 📄 [PostfixEvaluatorTest](src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java)
+          - 📄 [PostfixToInfixTest](src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java)
+          - 📄 [PrefixEvaluatorTest](src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java)
+          - 📄 [PrefixToInfixTest](src/test/java/com/thealgorithms/stacks/PrefixToInfixTest.java)
+          - 📄 [SmallestElementConstantTimeTest](src/test/java/com/thealgorithms/stacks/SmallestElementConstantTimeTest.java)
+          - 📄 [SortStackTest](src/test/java/com/thealgorithms/stacks/SortStackTest.java)
+          - 📄 [StackPostfixNotationTest](src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
+          - 📄 [StackUsingTwoQueuesTest](src/test/java/com/thealgorithms/stacks/StackUsingTwoQueuesTest.java)
+        - 📁 **strings**
+          - 📄 [AhoCorasickTest](src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
+          - 📄 [AlphabeticalTest](src/test/java/com/thealgorithms/strings/AlphabeticalTest.java)
+          - 📄 [AnagramsTest](src/test/java/com/thealgorithms/strings/AnagramsTest.java)
+          - 📄 [CharactersSameTest](src/test/java/com/thealgorithms/strings/CharactersSameTest.java)
+          - 📄 [CheckVowelsTest](src/test/java/com/thealgorithms/strings/CheckVowelsTest.java)
+          - 📄 [CountCharTest](src/test/java/com/thealgorithms/strings/CountCharTest.java)
+          - 📄 [CountWordsTest](src/test/java/com/thealgorithms/strings/CountWordsTest.java)
+          - 📄 [HammingDistanceTest](src/test/java/com/thealgorithms/strings/HammingDistanceTest.java)
+          - 📄 [HorspoolSearchTest](src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java)
+          - 📄 [IsomorphicTest](src/test/java/com/thealgorithms/strings/IsomorphicTest.java)
+          - 📄 [LetterCombinationsOfPhoneNumberTest](src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java)
+          - 📄 [LongestCommonPrefixTest](src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java)
+          - 📄 [LongestNonRepetitiveSubstringTest](src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java)
+          - 📄 [LongestPalindromicSubstringTest](src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java)
+          - 📄 [LowerTest](src/test/java/com/thealgorithms/strings/LowerTest.java)
+          - 📄 [ManacherTest](src/test/java/com/thealgorithms/strings/ManacherTest.java)
+          - 📄 [MyAtoiTest](src/test/java/com/thealgorithms/strings/MyAtoiTest.java)
+          - 📄 [PalindromeTest](src/test/java/com/thealgorithms/strings/PalindromeTest.java)
+          - 📄 [PangramTest](src/test/java/com/thealgorithms/strings/PangramTest.java)
+          - 📄 [PermuteStringTest](src/test/java/com/thealgorithms/strings/PermuteStringTest.java)
+          - 📄 [ReturnSubsequenceTest](src/test/java/com/thealgorithms/strings/ReturnSubsequenceTest.java)
+          - 📄 [ReverseStringRecursiveTest](src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java)
+          - 📄 [ReverseStringTest](src/test/java/com/thealgorithms/strings/ReverseStringTest.java)
+          - 📄 [ReverseWordsInStringTest](src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java)
+          - 📄 [RotationTest](src/test/java/com/thealgorithms/strings/RotationTest.java)
+          - 📄 [StringCompressionTest](src/test/java/com/thealgorithms/strings/StringCompressionTest.java)
+          - 📄 [StringMatchFiniteAutomataTest](src/test/java/com/thealgorithms/strings/StringMatchFiniteAutomataTest.java)
+          - 📄 [UpperTest](src/test/java/com/thealgorithms/strings/UpperTest.java)
+          - 📄 [ValidParenthesesTest](src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java)
+          - 📄 [WordLadderTest](src/test/java/com/thealgorithms/strings/WordLadderTest.java)
+          - 📁 **zigZagPattern**
+            - 📄 [ZigZagPatternTest](src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java)
+        - 📁 **tree**
+          - 📄 [HeavyLightDecompositionTest](src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java)
\ No newline at end of file

From bb36d13c93cc2c3684e92eb5c78b79860e010179 Mon Sep 17 00:00:00 2001
From: KevinMwita7 <kevinmwita7@gmail.com>
Date: Mon, 30 Jun 2025 21:45:37 +0300
Subject: [PATCH 0834/1338] Add RR cache (#6307)

---
 .../datastructures/caches/RRCache.java        | 505 ++++++++++++++++++
 .../datastructures/caches/RRCacheTest.java    | 222 ++++++++
 2 files changed, 727 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/caches/RRCache.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/caches/RRCacheTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/caches/RRCache.java b/src/main/java/com/thealgorithms/datastructures/caches/RRCache.java
new file mode 100644
index 000000000000..1821872be9cd
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/caches/RRCache.java
@@ -0,0 +1,505 @@
+package com.thealgorithms.datastructures.caches;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.BiConsumer;
+
+/**
+ * A thread-safe generic cache implementation using the Random Replacement (RR) eviction policy.
+ * <p>
+ * The cache holds a fixed number of entries, defined by its capacity. When the cache is full and a
+ * new entry is added, one of the existing entries is selected at random and evicted to make space.
+ * <p>
+ * Optionally, entries can have a time-to-live (TTL) in milliseconds. If a TTL is set, entries will
+ * automatically expire and be removed upon access or insertion attempts.
+ * <p>
+ * Features:
+ * <ul>
+ *     <li>Random eviction when capacity is exceeded</li>
+ *     <li>Optional TTL (time-to-live in milliseconds) per entry or default TTL for all entries</li>
+ *     <li>Thread-safe access using locking</li>
+ *     <li>Hit and miss counters for cache statistics</li>
+ *     <li>Eviction listener callback support</li>
+ * </ul>
+ *
+ * @param <K> the type of keys maintained by this cache
+ * @param <V> the type of mapped values
+ * See <a href="https://en.wikipedia.org/wiki/Cache_replacement_policies#Random_replacement_(RR)">Random Replacement</a>
+ * @author Kevin Babu (<a href="https://www.github.com/KevinMwita7">GitHub</a>)
+ */
+public final class RRCache<K, V> {
+
+    private final int capacity;
+    private final long defaultTTL;
+    private final Map<K, CacheEntry<V>> cache;
+    private final List<K> keys;
+    private final Random random;
+    private final Lock lock;
+
+    private long hits = 0;
+    private long misses = 0;
+    private final BiConsumer<K, V> evictionListener;
+    private final EvictionStrategy<K, V> evictionStrategy;
+
+    /**
+     * Internal structure to store value + expiry timestamp.
+     *
+     * @param <V> the type of the value being cached
+     */
+    private static class CacheEntry<V> {
+        V value;
+        long expiryTime;
+
+        /**
+         * Constructs a new {@code CacheEntry} with the specified value and time-to-live (TTL).
+         *
+         * @param value     the value to cache
+         * @param ttlMillis the time-to-live in milliseconds
+         */
+        CacheEntry(V value, long ttlMillis) {
+            this.value = value;
+            this.expiryTime = System.currentTimeMillis() + ttlMillis;
+        }
+
+        /**
+         * Checks if the cache entry has expired.
+         *
+         * @return {@code true} if the current time is past the expiration time; {@code false} otherwise
+         */
+        boolean isExpired() {
+            return System.currentTimeMillis() > expiryTime;
+        }
+    }
+
+    /**
+     * Constructs a new {@code RRCache} instance using the provided {@link Builder}.
+     *
+     * <p>This constructor initializes the cache with the specified capacity and default TTL,
+     * sets up internal data structures (a {@code HashMap} for cache entries and an {@code ArrayList}
+     * for key tracking), and configures eviction and randomization behavior.
+     *
+     * @param builder the {@code Builder} object containing configuration parameters
+     */
+    private RRCache(Builder<K, V> builder) {
+        this.capacity = builder.capacity;
+        this.defaultTTL = builder.defaultTTL;
+        this.cache = new HashMap<>(builder.capacity);
+        this.keys = new ArrayList<>(builder.capacity);
+        this.random = builder.random != null ? builder.random : new Random();
+        this.lock = new ReentrantLock();
+        this.evictionListener = builder.evictionListener;
+        this.evictionStrategy = builder.evictionStrategy;
+    }
+
+    /**
+     * Retrieves the value associated with the specified key from the cache.
+     *
+     * <p>If the key is not present or the corresponding entry has expired, this method
+     * returns {@code null}. If an expired entry is found, it will be removed and the
+     * eviction listener (if any) will be notified. Cache hit-and-miss statistics are
+     * also updated accordingly.
+     *
+     * @param key the key whose associated value is to be returned; must not be {@code null}
+     * @return the cached value associated with the key, or {@code null} if not present or expired
+     * @throws IllegalArgumentException if {@code key} is {@code null}
+     */
+    public V get(K key) {
+        if (key == null) {
+            throw new IllegalArgumentException("Key must not be null");
+        }
+
+        lock.lock();
+        try {
+            evictionStrategy.onAccess(this);
+
+            CacheEntry<V> entry = cache.get(key);
+            if (entry == null || entry.isExpired()) {
+                if (entry != null) {
+                    removeKey(key);
+                    notifyEviction(key, entry.value);
+                }
+                misses++;
+                return null;
+            }
+            hits++;
+            return entry.value;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Adds a key-value pair to the cache using the default time-to-live (TTL).
+     *
+     * <p>The key may overwrite an existing entry. The actual insertion is delegated
+     * to the overloaded {@link #put(K, V, long)} method.
+     *
+     * @param key   the key to cache the value under
+     * @param value the value to be cached
+     */
+    public void put(K key, V value) {
+        put(key, value, defaultTTL);
+    }
+
+    /**
+     * Adds a key-value pair to the cache with a specified time-to-live (TTL).
+     *
+     * <p>If the key already exists, its value is updated and its TTL is reset. If the key
+     * does not exist and the cache is full, a random entry is evicted to make space.
+     * Expired entries are also cleaned up prior to any eviction. The eviction listener
+     * is notified when an entry gets evicted.
+     *
+     * @param key        the key to associate with the cached value; must not be {@code null}
+     * @param value      the value to be cached; must not be {@code null}
+     * @param ttlMillis  the time-to-live for this entry in milliseconds; must be >= 0
+     * @throws IllegalArgumentException if {@code key} or {@code value} is {@code null}, or if {@code ttlMillis} is negative
+     */
+    public void put(K key, V value, long ttlMillis) {
+        if (key == null || value == null) {
+            throw new IllegalArgumentException("Key and value must not be null");
+        }
+        if (ttlMillis < 0) {
+            throw new IllegalArgumentException("TTL must be >= 0");
+        }
+
+        lock.lock();
+        try {
+            if (cache.containsKey(key)) {
+                cache.put(key, new CacheEntry<>(value, ttlMillis));
+                return;
+            }
+
+            evictExpired();
+
+            if (cache.size() >= capacity) {
+                int idx = random.nextInt(keys.size());
+                K evictKey = keys.remove(idx);
+                CacheEntry<V> evictVal = cache.remove(evictKey);
+                notifyEviction(evictKey, evictVal.value);
+            }
+
+            cache.put(key, new CacheEntry<>(value, ttlMillis));
+            keys.add(key);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Removes all expired entries from the cache.
+     *
+     * <p>This method iterates through the list of cached keys and checks each associated
+     * entry for expiration. Expired entries are removed from both the key tracking list
+     * and the cache map. For each eviction, the eviction listener is notified.
+     */
+    private int evictExpired() {
+        Iterator<K> it = keys.iterator();
+        int expiredCount = 0;
+
+        while (it.hasNext()) {
+            K k = it.next();
+            CacheEntry<V> entry = cache.get(k);
+            if (entry != null && entry.isExpired()) {
+                it.remove();
+                cache.remove(k);
+                ++expiredCount;
+                notifyEviction(k, entry.value);
+            }
+        }
+        return expiredCount;
+    }
+
+    /**
+     * Removes the specified key and its associated entry from the cache.
+     *
+     * <p>This method deletes the key from both the cache map and the key tracking list.
+     *
+     * @param key the key to remove from the cache
+     */
+    private void removeKey(K key) {
+        cache.remove(key);
+        keys.remove(key);
+    }
+
+    /**
+     * Notifies the eviction listener, if one is registered, that a key-value pair has been evicted.
+     *
+     * <p>If the {@code evictionListener} is not {@code null}, it is invoked with the provided key
+     * and value. Any exceptions thrown by the listener are caught and logged to standard error,
+     * preventing them from disrupting cache operations.
+     *
+     * @param key   the key that was evicted
+     * @param value the value that was associated with the evicted key
+     */
+    private void notifyEviction(K key, V value) {
+        if (evictionListener != null) {
+            try {
+                evictionListener.accept(key, value);
+            } catch (Exception e) {
+                System.err.println("Eviction listener failed: " + e.getMessage());
+            }
+        }
+    }
+
+    /**
+     * Returns the number of successful cache lookups (hits).
+     *
+     * @return the number of cache hits
+     */
+    public long getHits() {
+        lock.lock();
+        try {
+            return hits;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns the number of failed cache lookups (misses), including expired entries.
+     *
+     * @return the number of cache misses
+     */
+    public long getMisses() {
+        lock.lock();
+        try {
+            return misses;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns the current number of entries in the cache, excluding expired ones.
+     *
+     * @return the current cache size
+     */
+    public int size() {
+        lock.lock();
+        try {
+            int cachedSize = cache.size();
+            int evictedCount = evictionStrategy.onAccess(this);
+            if (evictedCount > 0) {
+                return cachedSize - evictedCount;
+            }
+
+            // This runs if periodic eviction does not occur
+            int count = 0;
+            for (Map.Entry<K, CacheEntry<V>> entry : cache.entrySet()) {
+                if (!entry.getValue().isExpired()) {
+                    ++count;
+                }
+            }
+            return count;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns the current {@link EvictionStrategy} used by this cache instance.
+
+     * @return the eviction strategy currently assigned to this cache
+     */
+    public EvictionStrategy<K, V> getEvictionStrategy() {
+        return evictionStrategy;
+    }
+
+    /**
+     * Returns a string representation of the cache, including metadata and current non-expired entries.
+     *
+     * <p>The returned string includes the cache's capacity, current size (excluding expired entries),
+     * hit-and-miss counts, and a map of all non-expired key-value pairs. This method acquires a lock
+     * to ensure thread-safe access.
+     *
+     * @return a string summarizing the state of the cache
+     */
+    @Override
+    public String toString() {
+        lock.lock();
+        try {
+            Map<K, V> visible = new HashMap<>();
+            for (Map.Entry<K, CacheEntry<V>> entry : cache.entrySet()) {
+                if (!entry.getValue().isExpired()) {
+                    visible.put(entry.getKey(), entry.getValue().value);
+                }
+            }
+            return String.format("Cache(capacity=%d, size=%d, hits=%d, misses=%d, entries=%s)", capacity, visible.size(), hits, misses, visible);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * A strategy interface for controlling when expired entries are evicted from the cache.
+     *
+     * <p>Implementations decide whether and when to trigger {@link RRCache#evictExpired()} based
+     * on cache usage patterns. This allows for flexible eviction behaviour such as periodic cleanup,
+     * or no automatic cleanup.
+     *
+     * @param <K> the type of keys maintained by the cache
+     * @param <V> the type of cached values
+     */
+    public interface EvictionStrategy<K, V> {
+        /**
+         * Called on each cache access (e.g., {@link RRCache#get(Object)}) to optionally trigger eviction.
+         *
+         * @param cache the cache instance on which this strategy is applied
+         * @return the number of expired entries evicted during this access
+         */
+        int onAccess(RRCache<K, V> cache);
+    }
+
+    /**
+     * An eviction strategy that performs eviction of expired entries on each call.
+     *
+     * @param <K> the type of keys
+     * @param <V> the type of values
+     */
+    public static class NoEvictionStrategy<K, V> implements EvictionStrategy<K, V> {
+        @Override
+        public int onAccess(RRCache<K, V> cache) {
+            return cache.evictExpired();
+        }
+    }
+
+    /**
+     * An eviction strategy that triggers eviction every fixed number of accesses.
+     *
+     * <p>This deterministic strategy ensures cleanup occurs at predictable intervals,
+     * ideal for moderately active caches where memory usage is a concern.
+     *
+     * @param <K> the type of keys
+     * @param <V> the type of values
+     */
+    public static class PeriodicEvictionStrategy<K, V> implements EvictionStrategy<K, V> {
+        private final int interval;
+        private int counter = 0;
+
+        /**
+         * Constructs a periodic eviction strategy.
+         *
+         * @param interval the number of accesses between evictions; must be > 0
+         * @throws IllegalArgumentException if {@code interval} is less than or equal to 0
+         */
+        public PeriodicEvictionStrategy(int interval) {
+            if (interval <= 0) {
+                throw new IllegalArgumentException("Interval must be > 0");
+            }
+            this.interval = interval;
+        }
+
+        @Override
+        public int onAccess(RRCache<K, V> cache) {
+            if (++counter % interval == 0) {
+                return cache.evictExpired();
+            }
+
+            return 0;
+        }
+    }
+
+    /**
+     * A builder for constructing an {@link RRCache} instance with customizable settings.
+     *
+     * <p>Allows configuring capacity, default TTL, random eviction behavior, eviction listener,
+     * and a pluggable eviction strategy. Call {@link #build()} to create the configured cache instance.
+     *
+     * @param <K> the type of keys maintained by the cache
+     * @param <V> the type of values stored in the cache
+     */
+    public static class Builder<K, V> {
+        private final int capacity;
+        private long defaultTTL = 0;
+        private Random random;
+        private BiConsumer<K, V> evictionListener;
+        private EvictionStrategy<K, V> evictionStrategy = new RRCache.PeriodicEvictionStrategy<>(100);
+        /**
+         * Creates a new {@code Builder} with the specified cache capacity.
+         *
+         * @param capacity the maximum number of entries the cache can hold; must be > 0
+         * @throws IllegalArgumentException if {@code capacity} is less than or equal to 0
+         */
+        public Builder(int capacity) {
+            if (capacity <= 0) {
+                throw new IllegalArgumentException("Capacity must be > 0");
+            }
+            this.capacity = capacity;
+        }
+
+        /**
+         * Sets the default time-to-live (TTL) in milliseconds for cache entries.
+         *
+         * @param ttlMillis the TTL duration in milliseconds; must be >= 0
+         * @return this builder instance for chaining
+         * @throws IllegalArgumentException if {@code ttlMillis} is negative
+         */
+        public Builder<K, V> defaultTTL(long ttlMillis) {
+            if (ttlMillis < 0) {
+                throw new IllegalArgumentException("Default TTL must be >= 0");
+            }
+            this.defaultTTL = ttlMillis;
+            return this;
+        }
+
+        /**
+         * Sets the {@link Random} instance to be used for random eviction selection.
+         *
+         * @param r a non-null {@code Random} instance
+         * @return this builder instance for chaining
+         * @throws IllegalArgumentException if {@code r} is {@code null}
+         */
+        public Builder<K, V> random(Random r) {
+            if (r == null) {
+                throw new IllegalArgumentException("Random must not be null");
+            }
+            this.random = r;
+            return this;
+        }
+
+        /**
+         * Sets an eviction listener to be notified when entries are evicted from the cache.
+         *
+         * @param listener a {@link BiConsumer} that accepts evicted keys and values; must not be {@code null}
+         * @return this builder instance for chaining
+         * @throws IllegalArgumentException if {@code listener} is {@code null}
+         */
+        public Builder<K, V> evictionListener(BiConsumer<K, V> listener) {
+            if (listener == null) {
+                throw new IllegalArgumentException("Listener must not be null");
+            }
+            this.evictionListener = listener;
+            return this;
+        }
+
+        /**
+         * Builds and returns a new {@link RRCache} instance with the configured parameters.
+         *
+         * @return a fully configured {@code RRCache} instance
+         */
+        public RRCache<K, V> build() {
+            return new RRCache<>(this);
+        }
+
+        /**
+         * Sets the eviction strategy used to determine when to clean up expired entries.
+         *
+         * @param strategy an {@link EvictionStrategy} implementation; must not be {@code null}
+         * @return this builder instance
+         * @throws IllegalArgumentException if {@code strategy} is {@code null}
+         */
+        public Builder<K, V> evictionStrategy(EvictionStrategy<K, V> strategy) {
+            if (strategy == null) {
+                throw new IllegalArgumentException("Eviction strategy must not be null");
+            }
+            this.evictionStrategy = strategy;
+            return this;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/caches/RRCacheTest.java b/src/test/java/com/thealgorithms/datastructures/caches/RRCacheTest.java
new file mode 100644
index 000000000000..100c73ea2a5b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/caches/RRCacheTest.java
@@ -0,0 +1,222 @@
+package com.thealgorithms.datastructures.caches;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Random;
+import java.util.Set;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.function.Executable;
+
+class RRCacheTest {
+
+    private RRCache<String, String> cache;
+    private Set<String> evictedKeys;
+    private List<String> evictedValues;
+
+    @BeforeEach
+    void setUp() {
+        evictedKeys = new HashSet<>();
+        evictedValues = new ArrayList<>();
+
+        cache = new RRCache.Builder<String, String>(3)
+                    .defaultTTL(1000)
+                    .random(new Random(0))
+                    .evictionListener((k, v) -> {
+                        evictedKeys.add(k);
+                        evictedValues.add(v);
+                    })
+                    .build();
+    }
+
+    @Test
+    void testPutAndGet() {
+        cache.put("a", "apple");
+        Assertions.assertEquals("apple", cache.get("a"));
+    }
+
+    @Test
+    void testOverwriteValue() {
+        cache.put("a", "apple");
+        cache.put("a", "avocado");
+        Assertions.assertEquals("avocado", cache.get("a"));
+    }
+
+    @Test
+    void testExpiration() throws InterruptedException {
+        cache.put("temp", "value", 100); // short TTL
+        Thread.sleep(200);
+        Assertions.assertNull(cache.get("temp"));
+        Assertions.assertTrue(evictedKeys.contains("temp"));
+    }
+
+    @Test
+    void testEvictionOnCapacity() {
+        cache.put("a", "alpha");
+        cache.put("b", "bravo");
+        cache.put("c", "charlie");
+        cache.put("d", "delta"); // triggers eviction
+
+        int size = cache.size();
+        Assertions.assertEquals(3, size);
+        Assertions.assertEquals(1, evictedKeys.size());
+        Assertions.assertEquals(1, evictedValues.size());
+    }
+
+    @Test
+    void testEvictionListener() {
+        cache.put("x", "one");
+        cache.put("y", "two");
+        cache.put("z", "three");
+        cache.put("w", "four"); // one of x, y, z will be evicted
+
+        Assertions.assertFalse(evictedKeys.isEmpty());
+        Assertions.assertFalse(evictedValues.isEmpty());
+    }
+
+    @Test
+    void testHitsAndMisses() {
+        cache.put("a", "apple");
+        Assertions.assertEquals("apple", cache.get("a"));
+        Assertions.assertNull(cache.get("b"));
+        Assertions.assertEquals(1, cache.getHits());
+        Assertions.assertEquals(1, cache.getMisses());
+    }
+
+    @Test
+    void testSizeExcludesExpired() throws InterruptedException {
+        cache.put("a", "a", 100);
+        cache.put("b", "b", 100);
+        cache.put("c", "c", 100);
+        Thread.sleep(150);
+        Assertions.assertEquals(0, cache.size());
+    }
+
+    @Test
+    void testToStringDoesNotExposeExpired() throws InterruptedException {
+        cache.put("live", "alive");
+        cache.put("dead", "gone", 100);
+        Thread.sleep(150);
+        String result = cache.toString();
+        Assertions.assertTrue(result.contains("live"));
+        Assertions.assertFalse(result.contains("dead"));
+    }
+
+    @Test
+    void testNullKeyGetThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.get(null));
+    }
+
+    @Test
+    void testPutNullKeyThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.put(null, "v"));
+    }
+
+    @Test
+    void testPutNullValueThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.put("k", null));
+    }
+
+    @Test
+    void testPutNegativeTTLThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.put("k", "v", -1));
+    }
+
+    @Test
+    void testBuilderNegativeCapacityThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new RRCache.Builder<>(0));
+    }
+
+    @Test
+    void testBuilderNullRandomThrows() {
+        RRCache.Builder<String, String> builder = new RRCache.Builder<>(1);
+        Assertions.assertThrows(IllegalArgumentException.class, () -> builder.random(null));
+    }
+
+    @Test
+    void testBuilderNullEvictionListenerThrows() {
+        RRCache.Builder<String, String> builder = new RRCache.Builder<>(1);
+        Assertions.assertThrows(IllegalArgumentException.class, () -> builder.evictionListener(null));
+    }
+
+    @Test
+    void testEvictionListenerExceptionDoesNotCrash() {
+        RRCache<String, String> listenerCache = new RRCache.Builder<String, String>(1).evictionListener((k, v) -> { throw new RuntimeException("Exception"); }).build();
+
+        listenerCache.put("a", "a");
+        listenerCache.put("b", "b"); // causes eviction but should not crash
+        Assertions.assertDoesNotThrow(() -> listenerCache.get("a"));
+    }
+
+    @Test
+    void testTtlZeroThrowsIllegalArgumentException() {
+        Executable exec = () -> new RRCache.Builder<String, String>(3).defaultTTL(-1).build();
+        Assertions.assertThrows(IllegalArgumentException.class, exec);
+    }
+
+    @Test
+    void testPeriodicEvictionStrategyEvictsAtInterval() throws InterruptedException {
+        RRCache<String, String> periodicCache = new RRCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(new RRCache.PeriodicEvictionStrategy<>(3)).build();
+
+        periodicCache.put("x", "1");
+        Thread.sleep(100);
+        int ev1 = periodicCache.getEvictionStrategy().onAccess(periodicCache);
+        int ev2 = periodicCache.getEvictionStrategy().onAccess(periodicCache);
+        int ev3 = periodicCache.getEvictionStrategy().onAccess(periodicCache);
+
+        Assertions.assertEquals(0, ev1);
+        Assertions.assertEquals(0, ev2);
+        Assertions.assertEquals(1, ev3, "Eviction should happen on the 3rd access");
+        Assertions.assertEquals(0, periodicCache.size());
+    }
+
+    @Test
+    void testPeriodicEvictionStrategyThrowsExceptionIfIntervalLessThanOrEqual0() {
+        Executable executable = () -> new RRCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(new RRCache.PeriodicEvictionStrategy<>(0)).build();
+
+        Assertions.assertThrows(IllegalArgumentException.class, executable);
+    }
+
+    @Test
+    void testNoEvictionStrategyEvictsOnEachCall() throws InterruptedException {
+        RRCache<String, String> noEvictionStrategyCache = new RRCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(new RRCache.NoEvictionStrategy<>()).build();
+
+        noEvictionStrategyCache.put("x", "1");
+        Thread.sleep(100);
+        int evicted = noEvictionStrategyCache.getEvictionStrategy().onAccess(noEvictionStrategyCache);
+
+        Assertions.assertEquals(1, evicted);
+    }
+
+    @Test
+    void testBuilderThrowsExceptionIfEvictionStrategyNull() {
+        Executable executable = () -> new RRCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(null).build();
+
+        Assertions.assertThrows(IllegalArgumentException.class, executable);
+    }
+
+    @Test
+    void testReturnsCorrectStrategyInstance() {
+        RRCache.EvictionStrategy<String, String> strategy = new RRCache.NoEvictionStrategy<>();
+
+        RRCache<String, String> newCache = new RRCache.Builder<String, String>(10).defaultTTL(1000).evictionStrategy(strategy).build();
+
+        Assertions.assertSame(strategy, newCache.getEvictionStrategy(), "Returned strategy should be the same instance");
+    }
+
+    @Test
+    void testDefaultStrategyIsNoEviction() {
+        RRCache<String, String> newCache = new RRCache.Builder<String, String>(5).defaultTTL(1000).build();
+
+        Assertions.assertTrue(newCache.getEvictionStrategy() instanceof RRCache.PeriodicEvictionStrategy<String, String>, "Default strategy should be NoEvictionStrategy");
+    }
+
+    @Test
+    void testGetEvictionStrategyIsNotNull() {
+        RRCache<String, String> newCache = new RRCache.Builder<String, String>(5).build();
+
+        Assertions.assertNotNull(newCache.getEvictionStrategy(), "Eviction strategy should never be null");
+    }
+}

From 7da9c6dd63d77491c0c27742cf81fc0122846b5e Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Mon, 30 Jun 2025 20:58:21 +0200
Subject: [PATCH 0835/1338] Update DIRECTORY.md (#6329)

---
 DIRECTORY.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7a4c25afe9ca..6158a02f3cb5 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -131,6 +131,7 @@
             - 📄 [LFUCache](src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java)
             - 📄 [LRUCache](src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java)
             - 📄 [MRUCache](src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java)
+            - 📄 [RRCache](src/main/java/com/thealgorithms/datastructures/caches/RRCache.java)
           - 📁 **crdt**
             - 📄 [GCounter](src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java)
             - 📄 [GSet](src/main/java/com/thealgorithms/datastructures/crdt/GSet.java)
@@ -872,6 +873,7 @@
             - 📄 [LFUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java)
             - 📄 [LRUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java)
             - 📄 [MRUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java)
+            - 📄 [RRCacheTest](src/test/java/com/thealgorithms/datastructures/caches/RRCacheTest.java)
           - 📁 **crdt**
             - 📄 [GCounterTest](src/test/java/com/thealgorithms/datastructures/crdt/GCounterTest.java)
             - 📄 [GSetTest](src/test/java/com/thealgorithms/datastructures/crdt/GSetTest.java)

From 55d08d657d13bd63408bea384ff5f6e15f1626e5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 1 Jul 2025 00:11:54 +0300
Subject: [PATCH 0836/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 10.26.0 to 10.26.1 (#6331)

chore(deps): bump com.puppycrawl.tools:checkstyle

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.26.0 to 10.26.1.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.26.0...checkstyle-10.26.1)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 10.26.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 0b638c1fc709..d0cfbae9ca98 100644
--- a/pom.xml
+++ b/pom.xml
@@ -113,7 +113,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.26.0</version>
+                    <version>10.26.1</version>
                     </dependency>
                 </dependencies>
             </plugin>

From ebf5c3d326502cbc6b22d84b489cea9996817bc7 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 1 Jul 2025 15:37:33 +0000
Subject: [PATCH 0837/1338] chore(deps): bump peter-evans/create-pull-request
 from 5 to 7 in /.github/workflows (#6330)

chore(deps): bump peter-evans/create-pull-request in /.github/workflows

Bumps [peter-evans/create-pull-request](https://github.com/peter-evans/create-pull-request) from 5 to 7.
- [Release notes](https://github.com/peter-evans/create-pull-request/releases)
- [Commits](https://github.com/peter-evans/create-pull-request/compare/v5...v7)

---
updated-dependencies:
- dependency-name: peter-evans/create-pull-request
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/update-directorymd.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index 6bc6485f61fb..53ad221e7742 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -31,7 +31,7 @@ jobs:
           git diff --cached --quiet || git commit -m "Update DIRECTORY.md"
       
       - name: Create Pull Request
-        uses: peter-evans/create-pull-request@v5
+        uses: peter-evans/create-pull-request@v7
         with:
           token: ${{ secrets.REPO_SCOPED_TOKEN }}
           branch: update-directory

From 712ada5102be82b4807b0737ad70cfc0bca37935 Mon Sep 17 00:00:00 2001
From: codingmydna <readchucastle@gmail.com>
Date: Wed, 2 Jul 2025 21:51:56 +0900
Subject: [PATCH 0838/1338] Correct column pointer initialization in
 RowColumnWiseSorted2dArrayBinarySearch (#6333)

---
 ...owColumnWiseSorted2dArrayBinarySearch.java |   2 +-
 ...lumnWiseSorted2dArrayBinarySearchTest.java | 127 ++++++++++++++++++
 2 files changed, 128 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java b/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java
index 3b4b0b08377f..b40c7554d84b 100644
--- a/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java
@@ -29,7 +29,7 @@ public <T extends Comparable<T>> int[] find(T[][] matrix, T key) {
 
     public static <T extends Comparable<T>> int[] search(T[][] matrix, T target) {
         int rowPointer = 0; // The pointer at 0th row
-        int colPointer = matrix.length - 1; // The pointer at end column
+        int colPointer = matrix[0].length - 1; // The pointer at end column
 
         while (rowPointer < matrix.length && colPointer >= 0) {
             int comp = target.compareTo(matrix[rowPointer][colPointer]);
diff --git a/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java
index 39ac5bf037ea..8d1423cbeeb0 100644
--- a/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java
@@ -110,4 +110,131 @@ public void rowColumnSorted2dArrayBinarySearchTestNotFound() {
         assertEquals(expected[0], ans[0]);
         assertEquals(expected[1], ans[1]);
     }
+
+    /**
+     * Tests for a WIDE rectangular matrix (3 rows, 4 columns)
+     */
+    private static final Integer[][] WIDE_RECTANGULAR_MATRIX = {
+        {10, 20, 30, 40},
+        {15, 25, 35, 45},
+        {18, 28, 38, 48},
+    };
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestWideMatrixMiddle() {
+        Integer target = 25; // A value in the middle
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(WIDE_RECTANGULAR_MATRIX, target);
+        int[] expected = {1, 1};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestWideMatrixTopRightCorner() {
+        Integer target = 40; // The top-right corner element
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(WIDE_RECTANGULAR_MATRIX, target);
+        int[] expected = {0, 3};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestWideMatrixBottomLeftCorner() {
+        Integer target = 18; // The bottom-left corner element
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(WIDE_RECTANGULAR_MATRIX, target);
+        int[] expected = {2, 0};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestWideMatrixTopLeftCorner() {
+        Integer target = 10; // The top-left corner element
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(WIDE_RECTANGULAR_MATRIX, target);
+        int[] expected = {0, 0};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestWideMatrixBottomRightCorner() {
+        Integer target = 48; // The bottom-right corner element
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(WIDE_RECTANGULAR_MATRIX, target);
+        int[] expected = {2, 3};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestWideMatrixNotFound() {
+        Integer target = 99; // A value that does not exist
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(WIDE_RECTANGULAR_MATRIX, target);
+        int[] expected = {-1, -1};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    /**
+     * Tests for a TALL rectangular matrix (4 rows, 3 columns)
+     */
+    private static final Integer[][] TALL_RECTANGULAR_MATRIX = {
+        {10, 20, 30},
+        {15, 25, 35},
+        {18, 28, 38},
+        {21, 31, 41},
+    };
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestTallMatrixMiddle() {
+        Integer target = 28; // A value in the middle
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(TALL_RECTANGULAR_MATRIX, target);
+        int[] expected = {2, 1};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestTallMatrixTopRightCorner() {
+        Integer target = 30; // The top-right corner element
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(TALL_RECTANGULAR_MATRIX, target);
+        int[] expected = {0, 2};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestTallMatrixBottomLeftCorner() {
+        Integer target = 21; // The bottom-left corner element
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(TALL_RECTANGULAR_MATRIX, target);
+        int[] expected = {3, 0};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestTallMatrixTopLeftCorner() {
+        Integer target = 10; // The top-left corner element
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(TALL_RECTANGULAR_MATRIX, target);
+        int[] expected = {0, 0};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestTallMatrixBottomRightCorner() {
+        Integer target = 41; // The bottom-right corner element
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(TALL_RECTANGULAR_MATRIX, target);
+        int[] expected = {3, 2};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void rowColumnSorted2dArrayBinarySearchTestTallMatrixNotFound() {
+        Integer target = 5; // A value that does not exist
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(TALL_RECTANGULAR_MATRIX, target);
+        int[] expected = {-1, -1};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
 }

From 58ac54cbdbc6d8f006e4fcb753f6ac416521702b Mon Sep 17 00:00:00 2001
From: Aditya <aditya.12114424@lpu.in>
Date: Fri, 4 Jul 2025 15:46:57 +0530
Subject: [PATCH 0839/1338] Add Freivalds' Algorithm for randomized matrix
 multiplication verification (#6340)

---
 ...mizedMatrixMultiplicationVerification.java | 64 +++++++++++++++++++
 ...dMatrixMultiplicationVerificationTest.java | 41 ++++++++++++
 2 files changed, 105 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/randomized/RandomizedMatrixMultiplicationVerification.java
 create mode 100644 src/test/java/com/thealgorithms/randomized/RandomizedMatrixMultiplicationVerificationTest.java

diff --git a/src/main/java/com/thealgorithms/randomized/RandomizedMatrixMultiplicationVerification.java b/src/main/java/com/thealgorithms/randomized/RandomizedMatrixMultiplicationVerification.java
new file mode 100644
index 000000000000..b5ac7076bfd6
--- /dev/null
+++ b/src/main/java/com/thealgorithms/randomized/RandomizedMatrixMultiplicationVerification.java
@@ -0,0 +1,64 @@
+package com.thealgorithms.randomized;
+
+import java.util.Random;
+
+public final class RandomizedMatrixMultiplicationVerification {
+
+    private RandomizedMatrixMultiplicationVerification() {
+        // Prevent instantiation of utility class
+    }
+
+    /**
+     * Verifies whether A × B == C using Freivalds' algorithm.
+     * @param A Left matrix
+     * @param B Right matrix
+     * @param C Product matrix to verify
+     * @param iterations Number of randomized checks
+     * @return true if likely A×B == C; false if definitely not
+     */
+    public static boolean verify(int[][] a, int[][] b, int[][] c, int iterations) {
+        int n = a.length;
+        Random random = new Random();
+
+        for (int iter = 0; iter < iterations; iter++) {
+            // Step 1: Generate random 0/1 vector
+            int[] r = new int[n];
+            for (int i = 0; i < n; i++) {
+                r[i] = random.nextInt(2);
+            }
+
+            // Step 2: Compute br = b × r
+            int[] br = new int[n];
+            for (int i = 0; i < n; i++) {
+                for (int j = 0; j < n; j++) {
+                    br[i] += b[i][j] * r[j];
+                }
+            }
+
+            // Step 3: Compute a(br)
+            int[] abr = new int[n];
+            for (int i = 0; i < n; i++) {
+                for (int j = 0; j < n; j++) {
+                    abr[i] += a[i][j] * br[j];
+                }
+            }
+
+            // Step 4: Compute cr = c × r
+            int[] cr = new int[n];
+            for (int i = 0; i < n; i++) {
+                for (int j = 0; j < n; j++) {
+                    cr[i] += c[i][j] * r[j];
+                }
+            }
+
+            // Step 5: Compare abr and cr
+            for (int i = 0; i < n; i++) {
+                if (abr[i] != cr[i]) {
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/randomized/RandomizedMatrixMultiplicationVerificationTest.java b/src/test/java/com/thealgorithms/randomized/RandomizedMatrixMultiplicationVerificationTest.java
new file mode 100644
index 000000000000..330662ac2c52
--- /dev/null
+++ b/src/test/java/com/thealgorithms/randomized/RandomizedMatrixMultiplicationVerificationTest.java
@@ -0,0 +1,41 @@
+package com.thealgorithms.randomized;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class RandomizedMatrixMultiplicationVerificationTest {
+
+    @Test
+    void testCorrectMultiplication() {
+        int[][] a = {{1, 2}, {3, 4}};
+        int[][] b = {{5, 6}, {7, 8}};
+        int[][] c = {{19, 22}, {43, 50}};
+        assertTrue(RandomizedMatrixMultiplicationVerification.verify(a, b, c, 10));
+    }
+
+    @Test
+    void testIncorrectMultiplication() {
+        int[][] a = {{1, 2}, {3, 4}};
+        int[][] b = {{5, 6}, {7, 8}};
+        int[][] wrongC = {{20, 22}, {43, 51}};
+        assertFalse(RandomizedMatrixMultiplicationVerification.verify(a, b, wrongC, 10));
+    }
+
+    @Test
+    void testLargeMatrix() {
+        int size = 100;
+        int[][] a = new int[size][size];
+        int[][] b = new int[size][size];
+        int[][] c = new int[size][size];
+
+        for (int i = 0; i < size; i++) {
+            a[i][i] = 1;
+            b[i][i] = 1;
+            c[i][i] = 1;
+        }
+
+        assertTrue(RandomizedMatrixMultiplicationVerification.verify(a, b, c, 15));
+    }
+}

From d709317b2e46fff578a8515f8fc89441cc4dd6c6 Mon Sep 17 00:00:00 2001
From: Aditya <aditya.12114424@lpu.in>
Date: Fri, 4 Jul 2025 15:53:49 +0530
Subject: [PATCH 0840/1338] Add RandomizedClosestPair Algorithm and Unit Tests
 (#6339)

---
 .../randomized/RandomizedClosestPair.java     | 113 ++++++++++++++++++
 .../randomized/RandomizedClosestPairTest.java |  30 +++++
 2 files changed, 143 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/randomized/RandomizedClosestPair.java
 create mode 100644 src/test/java/com/thealgorithms/randomized/RandomizedClosestPairTest.java

diff --git a/src/main/java/com/thealgorithms/randomized/RandomizedClosestPair.java b/src/main/java/com/thealgorithms/randomized/RandomizedClosestPair.java
new file mode 100644
index 000000000000..616f7fb7d7cf
--- /dev/null
+++ b/src/main/java/com/thealgorithms/randomized/RandomizedClosestPair.java
@@ -0,0 +1,113 @@
+package com.thealgorithms.randomized;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Random;
+
+/**
+ * Randomized Closest Pair of Points Algorithm
+ *
+ * Use Case:
+ * - Efficiently finds the closest pair of points in a 2D plane.
+ * - Applicable in computational geometry, clustering, and graphics.
+ *
+ * Time Complexity:
+ * - Expected: O(n log n) using randomized divide and conquer
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Closest_pair_of_points_problem">Closest Pair of Points - Wikipedia</a>
+ */
+public final class RandomizedClosestPair {
+
+    // Prevent instantiation of utility class
+    private RandomizedClosestPair() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    public static class Point {
+        public final double x;
+        public final double y;
+
+        public Point(double x, double y) {
+            this.x = x;
+            this.y = y;
+        }
+    }
+
+    public static double findClosestPairDistance(Point[] points) {
+        List<Point> shuffled = new ArrayList<>(Arrays.asList(points));
+        Collections.shuffle(shuffled, new Random());
+
+        Point[] px = shuffled.toArray(new Point[0]);
+        Arrays.sort(px, Comparator.comparingDouble(p -> p.x));
+
+        Point[] py = px.clone();
+        Arrays.sort(py, Comparator.comparingDouble(p -> p.y));
+
+        return closestPair(px, py);
+    }
+
+    private static double closestPair(Point[] px, Point[] py) {
+        int n = px.length;
+        if (n <= 3) {
+            return bruteForce(px);
+        }
+
+        int mid = n / 2;
+        Point midPoint = px[mid];
+
+        Point[] qx = Arrays.copyOfRange(px, 0, mid);
+        Point[] rx = Arrays.copyOfRange(px, mid, n);
+
+        List<Point> qy = new ArrayList<>();
+        List<Point> ry = new ArrayList<>();
+        for (Point p : py) {
+            if (p.x <= midPoint.x) {
+                qy.add(p);
+            } else {
+                ry.add(p);
+            }
+        }
+
+        double d1 = closestPair(qx, qy.toArray(new Point[0]));
+        double d2 = closestPair(rx, ry.toArray(new Point[0]));
+
+        double d = Math.min(d1, d2);
+
+        List<Point> strip = new ArrayList<>();
+        for (Point p : py) {
+            if (Math.abs(p.x - midPoint.x) < d) {
+                strip.add(p);
+            }
+        }
+
+        return Math.min(d, stripClosest(strip, d));
+    }
+
+    private static double bruteForce(Point[] points) {
+        double min = Double.POSITIVE_INFINITY;
+        for (int i = 0; i < points.length; i++) {
+            for (int j = i + 1; j < points.length; j++) {
+                min = Math.min(min, distance(points[i], points[j]));
+            }
+        }
+        return min;
+    }
+
+    private static double stripClosest(List<Point> strip, double d) {
+        double min = d;
+        int n = strip.size();
+        for (int i = 0; i < n; i++) {
+            for (int j = i + 1; j < n && (strip.get(j).y - strip.get(i).y) < min; j++) {
+                min = Math.min(min, distance(strip.get(i), strip.get(j)));
+            }
+        }
+        return min;
+    }
+
+    private static double distance(Point p1, Point p2) {
+        return Math.hypot(p1.x - p2.x, p1.y - p2.y);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/randomized/RandomizedClosestPairTest.java b/src/test/java/com/thealgorithms/randomized/RandomizedClosestPairTest.java
new file mode 100644
index 000000000000..fd739b743989
--- /dev/null
+++ b/src/test/java/com/thealgorithms/randomized/RandomizedClosestPairTest.java
@@ -0,0 +1,30 @@
+package com.thealgorithms.randomized;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.thealgorithms.randomized.RandomizedClosestPair.Point;
+import org.junit.jupiter.api.Test;
+
+public class RandomizedClosestPairTest {
+
+    @Test
+    public void testFindClosestPairDistance() {
+        Point[] points = {new Point(1, 1), new Point(2, 2), new Point(3, 3), new Point(8, 8), new Point(13, 13)};
+        double result = RandomizedClosestPair.findClosestPairDistance(points);
+        assertEquals(Math.sqrt(2), result, 0.00001);
+    }
+
+    @Test
+    public void testWithIdenticalPoints() {
+        Point[] points = {new Point(0, 0), new Point(0, 0), new Point(1, 1)};
+        double result = RandomizedClosestPair.findClosestPairDistance(points);
+        assertEquals(0.0, result, 0.00001);
+    }
+
+    @Test
+    public void testWithDistantPoints() {
+        Point[] points = {new Point(0, 0), new Point(5, 0), new Point(10, 0)};
+        double result = RandomizedClosestPair.findClosestPairDistance(points);
+        assertEquals(5.0, result, 0.00001);
+    }
+}

From 841f9c3bbdbc443ad26e6bb2f1e2206bcc3fb55e Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Fri, 4 Jul 2025 12:40:46 +0200
Subject: [PATCH 0841/1338] Update DIRECTORY.md (#6341)

Co-authored-by: siriak <siriak@users.noreply.github.com>
---
 DIRECTORY.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6158a02f3cb5..5a75847218b5 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -568,6 +568,8 @@
         - 📁 **randomized**
           - 📄 [KargerMinCut](src/main/java/com/thealgorithms/randomized/KargerMinCut.java)
           - 📄 [MonteCarloIntegration](src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java)
+          - 📄 [RandomizedClosestPair](src/main/java/com/thealgorithms/randomized/RandomizedClosestPair.java)
+          - 📄 [RandomizedMatrixMultiplicationVerification](src/main/java/com/thealgorithms/randomized/RandomizedMatrixMultiplicationVerification.java)
           - 📄 [RandomizedQuickSort](src/main/java/com/thealgorithms/randomized/RandomizedQuickSort.java)
           - 📄 [ReservoirSampling](src/main/java/com/thealgorithms/randomized/ReservoirSampling.java)
         - 📁 **recursion**
@@ -1233,6 +1235,8 @@
         - 📁 **randomized**
           - 📄 [KargerMinCutTest](src/test/java/com/thealgorithms/randomized/KargerMinCutTest.java)
           - 📄 [MonteCarloIntegrationTest](src/test/java/com/thealgorithms/randomized/MonteCarloIntegrationTest.java)
+          - 📄 [RandomizedClosestPairTest](src/test/java/com/thealgorithms/randomized/RandomizedClosestPairTest.java)
+          - 📄 [RandomizedMatrixMultiplicationVerificationTest](src/test/java/com/thealgorithms/randomized/RandomizedMatrixMultiplicationVerificationTest.java)
           - 📄 [RandomizedQuickSortTest](src/test/java/com/thealgorithms/randomized/RandomizedQuickSortTest.java)
           - 📄 [ReservoirSamplingTest](src/test/java/com/thealgorithms/randomized/ReservoirSamplingTest.java)
         - 📁 **recursion**

From 4360807575d354c49bd046fcb30de8db81344bdd Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 4 Jul 2025 23:36:42 +0200
Subject: [PATCH 0842/1338] chore(deps): bump org.junit:junit-bom from 5.13.2
 to 5.13.3 (#6343)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 5.13.2 to 5.13.3.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r5.13.2...r5.13.3)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 5.13.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index d0cfbae9ca98..ca2712d8c8ad 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.13.2</version>
+                <version>5.13.3</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From c782f05ed439d7aa4a939eb65e69e1aac65cf9fe Mon Sep 17 00:00:00 2001
From: KevinMwita7 <kevinmwita7@gmail.com>
Date: Sat, 5 Jul 2025 16:29:46 +0300
Subject: [PATCH 0843/1338] Add cache with FIFO replacement policy (#6337)

---
 .../datastructures/caches/FIFOCache.java      | 549 ++++++++++++++++++
 .../datastructures/caches/FIFOCacheTest.java  | 330 +++++++++++
 2 files changed, 879 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/caches/FIFOCache.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/caches/FIFOCacheTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/caches/FIFOCache.java b/src/main/java/com/thealgorithms/datastructures/caches/FIFOCache.java
new file mode 100644
index 000000000000..fa048434a187
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/caches/FIFOCache.java
@@ -0,0 +1,549 @@
+package com.thealgorithms.datastructures.caches;
+
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.BiConsumer;
+
+/**
+ * A thread-safe generic cache implementation using the First-In-First-Out eviction policy.
+ * <p>
+ * The cache holds a fixed number of entries, defined by its capacity. When the cache is full and a
+ * new entry is added, the oldest entry in the cache is selected and evicted to make space.
+ * <p>
+ * Optionally, entries can have a time-to-live (TTL) in milliseconds. If a TTL is set, entries will
+ * automatically expire and be removed upon access or insertion attempts.
+ * <p>
+ * Features:
+ * <ul>
+ *     <li>Removes oldest entry when capacity is exceeded</li>
+ *     <li>Optional TTL (time-to-live in milliseconds) per entry or default TTL for all entries</li>
+ *     <li>Thread-safe access using locking</li>
+ *     <li>Hit and miss counters for cache statistics</li>
+ *     <li>Eviction listener callback support</li>
+ * </ul>
+ *
+ * @param <K> the type of keys maintained by this cache
+ * @param <V> the type of mapped values
+ * See <a href="https://en.wikipedia.org/wiki/Cache_replacement_policies#First_in_first_out_(FIFO)">FIFO</a>
+ * @author Kevin Babu (<a href="https://www.github.com/KevinMwita7">GitHub</a>)
+ */
+public final class FIFOCache<K, V> {
+
+    private final int capacity;
+    private final long defaultTTL;
+    private final Map<K, CacheEntry<V>> cache;
+    private final Lock lock;
+
+    private long hits = 0;
+    private long misses = 0;
+    private final BiConsumer<K, V> evictionListener;
+    private final EvictionStrategy<K, V> evictionStrategy;
+
+    /**
+     * Internal structure to store value + expiry timestamp.
+     *
+     * @param <V> the type of the value being cached
+     */
+    private static class CacheEntry<V> {
+        V value;
+        long expiryTime;
+
+        /**
+         * Constructs a new {@code CacheEntry} with the specified value and time-to-live (TTL).
+         * If TTL is 0, the entry is kept indefinitely, that is, unless it is the first value,
+         * then it will be removed according to the FIFO principle
+         *
+         * @param value     the value to cache
+         * @param ttlMillis the time-to-live in milliseconds
+         */
+        CacheEntry(V value, long ttlMillis) {
+            this.value = value;
+            if (ttlMillis == 0) {
+                this.expiryTime = Long.MAX_VALUE;
+            } else {
+                this.expiryTime = System.currentTimeMillis() + ttlMillis;
+            }
+        }
+
+        /**
+         * Checks if the cache entry has expired.
+         *
+         * @return {@code true} if the current time is past the expiration time; {@code false} otherwise
+         */
+        boolean isExpired() {
+            return System.currentTimeMillis() > expiryTime;
+        }
+    }
+
+    /**
+     * Constructs a new {@code FIFOCache} instance using the provided {@link Builder}.
+     *
+     * <p>This constructor initializes the cache with the specified capacity and default TTL,
+     * sets up internal data structures (a {@code LinkedHashMap} for cache entries and configures eviction.
+     *
+     * @param builder the {@code Builder} object containing configuration parameters
+     */
+    private FIFOCache(Builder<K, V> builder) {
+        this.capacity = builder.capacity;
+        this.defaultTTL = builder.defaultTTL;
+        this.cache = new LinkedHashMap<>();
+        this.lock = new ReentrantLock();
+        this.evictionListener = builder.evictionListener;
+        this.evictionStrategy = builder.evictionStrategy;
+    }
+
+    /**
+     * Retrieves the value associated with the specified key from the cache.
+     *
+     * <p>If the key is not present or the corresponding entry has expired, this method
+     * returns {@code null}. If an expired entry is found, it will be removed and the
+     * eviction listener (if any) will be notified. Cache hit-and-miss statistics are
+     * also updated accordingly.
+     *
+     * @param key the key whose associated value is to be returned; must not be {@code null}
+     * @return the cached value associated with the key, or {@code null} if not present or expired
+     * @throws IllegalArgumentException if {@code key} is {@code null}
+     */
+    public V get(K key) {
+        if (key == null) {
+            throw new IllegalArgumentException("Key must not be null");
+        }
+
+        lock.lock();
+        try {
+            evictionStrategy.onAccess(this);
+
+            CacheEntry<V> entry = cache.get(key);
+            if (entry == null || entry.isExpired()) {
+                if (entry != null) {
+                    cache.remove(key);
+                    notifyEviction(key, entry.value);
+                }
+                misses++;
+                return null;
+            }
+            hits++;
+            return entry.value;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Adds a key-value pair to the cache using the default time-to-live (TTL).
+     *
+     * <p>The key may overwrite an existing entry. The actual insertion is delegated
+     * to the overloaded {@link #put(K, V, long)} method.
+     *
+     * @param key   the key to cache the value under
+     * @param value the value to be cached
+     */
+    public void put(K key, V value) {
+        put(key, value, defaultTTL);
+    }
+
+    /**
+     * Adds a key-value pair to the cache with a specified time-to-live (TTL).
+     *
+     * <p>If the key already exists, its value is removed, re-inserted at tail and its TTL is reset.
+     * If the key does not exist and the cache is full, the oldest entry is evicted to make space.
+     * Expired entries are also cleaned up prior to any eviction. The eviction listener
+     * is notified when an entry gets evicted.
+     *
+     * @param key        the key to associate with the cached value; must not be {@code null}
+     * @param value      the value to be cached; must not be {@code null}
+     * @param ttlMillis  the time-to-live for this entry in milliseconds; must be >= 0
+     * @throws IllegalArgumentException if {@code key} or {@code value} is {@code null}, or if {@code ttlMillis} is negative
+     */
+    public void put(K key, V value, long ttlMillis) {
+        if (key == null || value == null) {
+            throw new IllegalArgumentException("Key and value must not be null");
+        }
+        if (ttlMillis < 0) {
+            throw new IllegalArgumentException("TTL must be >= 0");
+        }
+
+        lock.lock();
+        try {
+            // If key already exists, remove it
+            CacheEntry<V> oldEntry = cache.remove(key);
+            if (oldEntry != null && !oldEntry.isExpired()) {
+                notifyEviction(key, oldEntry.value);
+            }
+
+            // Evict expired entries to make space for new entry
+            evictExpired();
+
+            // If no expired entry was removed, remove the oldest
+            if (cache.size() >= capacity) {
+                Iterator<Map.Entry<K, CacheEntry<V>>> it = cache.entrySet().iterator();
+                if (it.hasNext()) {
+                    Map.Entry<K, CacheEntry<V>> eldest = it.next();
+                    it.remove();
+                    notifyEviction(eldest.getKey(), eldest.getValue().value);
+                }
+            }
+
+            // Insert new entry at tail
+            cache.put(key, new CacheEntry<>(value, ttlMillis));
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Removes all expired entries from the cache.
+     *
+     * <p>This method iterates through the list of cached keys and checks each associated
+     * entry for expiration. Expired entries are removed the cache map. For each eviction,
+     * the eviction listener is notified.
+     */
+    private int evictExpired() {
+        int count = 0;
+        Iterator<Map.Entry<K, CacheEntry<V>>> it = cache.entrySet().iterator();
+
+        while (it.hasNext()) {
+            Map.Entry<K, CacheEntry<V>> entry = it.next();
+            if (entry != null && entry.getValue().isExpired()) {
+                it.remove();
+                notifyEviction(entry.getKey(), entry.getValue().value);
+                count++;
+            }
+        }
+
+        return count;
+    }
+
+    /**
+     * Removes the specified key and its associated entry from the cache.
+     *
+     * @param key the key to remove from the cache;
+     * @return the value associated with the key;  or {@code null} if no such key exists
+     */
+    public V removeKey(K key) {
+        if (key == null) {
+            throw new IllegalArgumentException("Key cannot be null");
+        }
+        CacheEntry<V> entry = cache.remove(key);
+
+        // No such key in cache
+        if (entry == null) {
+            return null;
+        }
+
+        notifyEviction(key, entry.value);
+        return entry.value;
+    }
+
+    /**
+     * Notifies the eviction listener, if one is registered, that a key-value pair has been evicted.
+     *
+     * <p>If the {@code evictionListener} is not {@code null}, it is invoked with the provided key
+     * and value. Any exceptions thrown by the listener are caught and logged to standard error,
+     * preventing them from disrupting cache operations.
+     *
+     * @param key   the key that was evicted
+     * @param value the value that was associated with the evicted key
+     */
+    private void notifyEviction(K key, V value) {
+        if (evictionListener != null) {
+            try {
+                evictionListener.accept(key, value);
+            } catch (Exception e) {
+                System.err.println("Eviction listener failed: " + e.getMessage());
+            }
+        }
+    }
+
+    /**
+     * Returns the number of successful cache lookups (hits).
+     *
+     * @return the number of cache hits
+     */
+    public long getHits() {
+        lock.lock();
+        try {
+            return hits;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns the number of failed cache lookups (misses), including expired entries.
+     *
+     * @return the number of cache misses
+     */
+    public long getMisses() {
+        lock.lock();
+        try {
+            return misses;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns the current number of entries in the cache, excluding expired ones.
+     *
+     * @return the current cache size
+     */
+    public int size() {
+        lock.lock();
+        try {
+            evictionStrategy.onAccess(this);
+
+            int count = 0;
+            for (CacheEntry<V> entry : cache.values()) {
+                if (!entry.isExpired()) {
+                    ++count;
+                }
+            }
+            return count;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Removes all entries from the cache, regardless of their expiration status.
+     *
+     * <p>This method clears the internal cache map entirely, resets the hit-and-miss counters,
+     * and notifies the eviction listener (if any) for each removed entry.
+     * Note that expired entries are treated the same as active ones for the purpose of clearing.
+     *
+     * <p>This operation acquires the internal lock to ensure thread safety.
+     */
+    public void clear() {
+        lock.lock();
+        try {
+            for (Map.Entry<K, CacheEntry<V>> entry : cache.entrySet()) {
+                notifyEviction(entry.getKey(), entry.getValue().value);
+            }
+            cache.clear();
+            hits = 0;
+            misses = 0;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns a set of all keys currently stored in the cache that have not expired.
+     *
+     * <p>This method iterates through the cache and collects the keys of all non-expired entries.
+     * Expired entries are ignored but not removed. If you want to ensure expired entries are cleaned up,
+     * consider invoking {@link EvictionStrategy#onAccess(FIFOCache)} or calling {@link #evictExpired()} manually.
+     *
+     * <p>This operation acquires the internal lock to ensure thread safety.
+     *
+     * @return a set containing all non-expired keys currently in the cache
+     */
+    public Set<K> getAllKeys() {
+        lock.lock();
+        try {
+            Set<K> keys = new LinkedHashSet<>();
+
+            for (Map.Entry<K, CacheEntry<V>> entry : cache.entrySet()) {
+                if (!entry.getValue().isExpired()) {
+                    keys.add(entry.getKey());
+                }
+            }
+
+            return keys;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns the current {@link EvictionStrategy} used by this cache instance.
+
+     * @return the eviction strategy currently assigned to this cache
+     */
+    public EvictionStrategy<K, V> getEvictionStrategy() {
+        return evictionStrategy;
+    }
+
+    /**
+     * Returns a string representation of the cache, including metadata and current non-expired entries.
+     *
+     * <p>The returned string includes the cache's capacity, current size (excluding expired entries),
+     * hit-and-miss counts, and a map of all non-expired key-value pairs. This method acquires a lock
+     * to ensure thread-safe access.
+     *
+     * @return a string summarizing the state of the cache
+     */
+    @Override
+    public String toString() {
+        lock.lock();
+        try {
+            Map<K, V> visible = new LinkedHashMap<>();
+            for (Map.Entry<K, CacheEntry<V>> entry : cache.entrySet()) {
+                if (!entry.getValue().isExpired()) {
+                    visible.put(entry.getKey(), entry.getValue().value);
+                }
+            }
+            return String.format("Cache(capacity=%d, size=%d, hits=%d, misses=%d, entries=%s)", capacity, visible.size(), hits, misses, visible);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * A strategy interface for controlling when expired entries are evicted from the cache.
+     *
+     * <p>Implementations decide whether and when to trigger {@link FIFOCache#evictExpired()} based
+     * on cache usage patterns. This allows for flexible eviction behaviour such as periodic cleanup,
+     * or no automatic cleanup.
+     *
+     * @param <K> the type of keys maintained by the cache
+     * @param <V> the type of cached values
+     */
+    public interface EvictionStrategy<K, V> {
+        /**
+         * Called on each cache access (e.g., {@link FIFOCache#get(Object)}) to optionally trigger eviction.
+         *
+         * @param cache the cache instance on which this strategy is applied
+         * @return the number of expired entries evicted during this access
+         */
+        int onAccess(FIFOCache<K, V> cache);
+    }
+
+    /**
+     * An eviction strategy that performs eviction of expired entries on each call.
+     *
+     * @param <K> the type of keys
+     * @param <V> the type of values
+     */
+    public static class ImmediateEvictionStrategy<K, V> implements EvictionStrategy<K, V> {
+        @Override
+        public int onAccess(FIFOCache<K, V> cache) {
+            return cache.evictExpired();
+        }
+    }
+
+    /**
+     * An eviction strategy that triggers eviction on every fixed number of accesses.
+     *
+     * <p>This deterministic strategy ensures cleanup occurs at predictable intervals,
+     * ideal for moderately active caches where memory usage is a concern.
+     *
+     * @param <K> the type of keys
+     * @param <V> the type of values
+     */
+    public static class PeriodicEvictionStrategy<K, V> implements EvictionStrategy<K, V> {
+        private final int interval;
+        private final AtomicInteger counter = new AtomicInteger();
+
+        /**
+         * Constructs a periodic eviction strategy.
+         *
+         * @param interval the number of accesses between evictions; must be > 0
+         * @throws IllegalArgumentException if {@code interval} is less than or equal to 0
+         */
+        public PeriodicEvictionStrategy(int interval) {
+            if (interval <= 0) {
+                throw new IllegalArgumentException("Interval must be > 0");
+            }
+            this.interval = interval;
+        }
+
+        @Override
+        public int onAccess(FIFOCache<K, V> cache) {
+            if (counter.incrementAndGet() % interval == 0) {
+                return cache.evictExpired();
+            }
+
+            return 0;
+        }
+    }
+
+    /**
+     * A builder for constructing a {@link FIFOCache} instance with customizable settings.
+     *
+     * <p>Allows configuring capacity, default TTL, eviction listener, and a pluggable eviction
+     * strategy. Call {@link #build()} to create the configured cache instance.
+     *
+     * @param <K> the type of keys maintained by the cache
+     * @param <V> the type of values stored in the cache
+     */
+    public static class Builder<K, V> {
+        private final int capacity;
+        private long defaultTTL = 0;
+        private BiConsumer<K, V> evictionListener;
+        private EvictionStrategy<K, V> evictionStrategy = new FIFOCache.ImmediateEvictionStrategy<>();
+        /**
+         * Creates a new {@code Builder} with the specified cache capacity.
+         *
+         * @param capacity the maximum number of entries the cache can hold; must be > 0
+         * @throws IllegalArgumentException if {@code capacity} is less than or equal to 0
+         */
+        public Builder(int capacity) {
+            if (capacity <= 0) {
+                throw new IllegalArgumentException("Capacity must be > 0");
+            }
+            this.capacity = capacity;
+        }
+
+        /**
+         * Sets the default time-to-live (TTL) in milliseconds for cache entries.
+         *
+         * @param ttlMillis the TTL duration in milliseconds; must be >= 0
+         * @return this builder instance for chaining
+         * @throws IllegalArgumentException if {@code ttlMillis} is negative
+         */
+        public Builder<K, V> defaultTTL(long ttlMillis) {
+            if (ttlMillis < 0) {
+                throw new IllegalArgumentException("Default TTL must be >= 0");
+            }
+            this.defaultTTL = ttlMillis;
+            return this;
+        }
+
+        /**
+         * Sets an eviction listener to be notified when entries are evicted from the cache.
+         *
+         * @param listener a {@link BiConsumer} that accepts evicted keys and values; must not be {@code null}
+         * @return this builder instance for chaining
+         * @throws IllegalArgumentException if {@code listener} is {@code null}
+         */
+        public Builder<K, V> evictionListener(BiConsumer<K, V> listener) {
+            if (listener == null) {
+                throw new IllegalArgumentException("Listener must not be null");
+            }
+            this.evictionListener = listener;
+            return this;
+        }
+
+        /**
+         * Builds and returns a new {@link FIFOCache} instance with the configured parameters.
+         *
+         * @return a fully configured {@code FIFOCache} instance
+         */
+        public FIFOCache<K, V> build() {
+            return new FIFOCache<>(this);
+        }
+
+        /**
+         * Sets the eviction strategy used to determine when to clean up expired entries.
+         *
+         * @param strategy an {@link EvictionStrategy} implementation; must not be {@code null}
+         * @return this builder instance
+         * @throws IllegalArgumentException if {@code strategy} is {@code null}
+         */
+        public Builder<K, V> evictionStrategy(EvictionStrategy<K, V> strategy) {
+            if (strategy == null) {
+                throw new IllegalArgumentException("Eviction strategy must not be null");
+            }
+            this.evictionStrategy = strategy;
+            return this;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/caches/FIFOCacheTest.java b/src/test/java/com/thealgorithms/datastructures/caches/FIFOCacheTest.java
new file mode 100644
index 000000000000..5f250e6ca3fd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/caches/FIFOCacheTest.java
@@ -0,0 +1,330 @@
+package com.thealgorithms.datastructures.caches;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.function.Executable;
+
+class FIFOCacheTest {
+    private FIFOCache<String, String> cache;
+    private Set<String> evictedKeys;
+    private List<String> evictedValues;
+
+    @BeforeEach
+    void setUp() {
+        evictedKeys = new HashSet<>();
+        evictedValues = new ArrayList<>();
+
+        cache = new FIFOCache.Builder<String, String>(3)
+                    .defaultTTL(1000)
+                    .evictionListener((k, v) -> {
+                        evictedKeys.add(k);
+                        evictedValues.add(v);
+                    })
+                    .build();
+    }
+
+    @Test
+    void testPutAndGet() {
+        cache.put("a", "apple");
+        Assertions.assertEquals("apple", cache.get("a"));
+    }
+
+    @Test
+    void testOverwriteValue() {
+        cache.put("a", "apple");
+        cache.put("a", "avocado");
+        Assertions.assertEquals("avocado", cache.get("a"));
+    }
+
+    @Test
+    void testExpiration() throws InterruptedException {
+        cache.put("temp", "value", 100);
+        Thread.sleep(200);
+        Assertions.assertNull(cache.get("temp"));
+        Assertions.assertTrue(evictedKeys.contains("temp"));
+    }
+
+    @Test
+    void testEvictionOnCapacity() {
+        cache.put("a", "alpha");
+        cache.put("b", "bravo");
+        cache.put("c", "charlie");
+        cache.put("d", "delta");
+
+        int size = cache.size();
+        Assertions.assertEquals(3, size);
+        Assertions.assertEquals(1, evictedKeys.size());
+        Assertions.assertEquals(1, evictedValues.size());
+    }
+
+    @Test
+    void testEvictionListener() {
+        cache.put("x", "one");
+        cache.put("y", "two");
+        cache.put("z", "three");
+        cache.put("w", "four");
+
+        Assertions.assertFalse(evictedKeys.isEmpty());
+        Assertions.assertFalse(evictedValues.isEmpty());
+    }
+
+    @Test
+    void testHitsAndMisses() {
+        cache.put("a", "apple");
+        Assertions.assertEquals("apple", cache.get("a"));
+        Assertions.assertNull(cache.get("b"));
+        Assertions.assertEquals(1, cache.getHits());
+        Assertions.assertEquals(1, cache.getMisses());
+    }
+
+    @Test
+    void testSizeExcludesExpired() throws InterruptedException {
+        cache.put("a", "a", 100);
+        cache.put("b", "b", 100);
+        cache.put("c", "c", 100);
+        Thread.sleep(150);
+        Assertions.assertEquals(0, cache.size());
+    }
+
+    @Test
+    void testSizeIncludesFresh() {
+        cache.put("a", "a", 1000);
+        cache.put("b", "b", 1000);
+        cache.put("c", "c", 1000);
+        Assertions.assertEquals(3, cache.size());
+    }
+
+    @Test
+    void testToStringDoesNotExposeExpired() throws InterruptedException {
+        cache.put("live", "alive");
+        cache.put("dead", "gone", 100);
+        Thread.sleep(150);
+        String result = cache.toString();
+        Assertions.assertTrue(result.contains("live"));
+        Assertions.assertFalse(result.contains("dead"));
+    }
+
+    @Test
+    void testNullKeyGetThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.get(null));
+    }
+
+    @Test
+    void testPutNullKeyThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.put(null, "v"));
+    }
+
+    @Test
+    void testPutNullValueThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.put("k", null));
+    }
+
+    @Test
+    void testPutNegativeTTLThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.put("k", "v", -1));
+    }
+
+    @Test
+    void testBuilderNegativeCapacityThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new FIFOCache.Builder<>(0));
+    }
+
+    @Test
+    void testBuilderNullEvictionListenerThrows() {
+        FIFOCache.Builder<String, String> builder = new FIFOCache.Builder<>(1);
+        Assertions.assertThrows(IllegalArgumentException.class, () -> builder.evictionListener(null));
+    }
+
+    @Test
+    void testEvictionListenerExceptionDoesNotCrash() {
+        FIFOCache<String, String> listenerCache = new FIFOCache.Builder<String, String>(1).evictionListener((k, v) -> { throw new RuntimeException("Exception"); }).build();
+
+        listenerCache.put("a", "a");
+        listenerCache.put("b", "b");
+        Assertions.assertDoesNotThrow(() -> listenerCache.get("a"));
+    }
+
+    @Test
+    void testTtlZeroThrowsIllegalArgumentException() {
+        Executable exec = () -> new FIFOCache.Builder<String, String>(3).defaultTTL(-1).build();
+        Assertions.assertThrows(IllegalArgumentException.class, exec);
+    }
+
+    @Test
+    void testPeriodicEvictionStrategyEvictsAtInterval() throws InterruptedException {
+        FIFOCache<String, String> periodicCache = new FIFOCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(new FIFOCache.PeriodicEvictionStrategy<>(3)).build();
+
+        periodicCache.put("x", "1");
+        Thread.sleep(100);
+        int ev1 = periodicCache.getEvictionStrategy().onAccess(periodicCache);
+        int ev2 = periodicCache.getEvictionStrategy().onAccess(periodicCache);
+        int ev3 = periodicCache.getEvictionStrategy().onAccess(periodicCache);
+
+        Assertions.assertEquals(0, ev1);
+        Assertions.assertEquals(0, ev2);
+        Assertions.assertEquals(1, ev3, "Eviction should happen on the 3rd access");
+        Assertions.assertEquals(0, periodicCache.size());
+    }
+
+    @Test
+    void testPeriodicEvictionStrategyThrowsExceptionIfIntervalLessThanOrEqual0() {
+        Executable executable = () -> new FIFOCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(new FIFOCache.PeriodicEvictionStrategy<>(0)).build();
+
+        Assertions.assertThrows(IllegalArgumentException.class, executable);
+    }
+
+    @Test
+    void testImmediateEvictionStrategyStrategyEvictsOnEachCall() throws InterruptedException {
+        FIFOCache<String, String> immediateEvictionStrategy = new FIFOCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(new FIFOCache.ImmediateEvictionStrategy<>()).build();
+
+        immediateEvictionStrategy.put("x", "1");
+        Thread.sleep(100);
+        int evicted = immediateEvictionStrategy.getEvictionStrategy().onAccess(immediateEvictionStrategy);
+
+        Assertions.assertEquals(1, evicted);
+    }
+
+    @Test
+    void testBuilderThrowsExceptionIfEvictionStrategyNull() {
+        Executable executable = () -> new FIFOCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(null).build();
+
+        Assertions.assertThrows(IllegalArgumentException.class, executable);
+    }
+
+    @Test
+    void testReturnsCorrectStrategyInstance() {
+        FIFOCache.EvictionStrategy<String, String> strategy = new FIFOCache.ImmediateEvictionStrategy<>();
+
+        FIFOCache<String, String> newCache = new FIFOCache.Builder<String, String>(10).defaultTTL(1000).evictionStrategy(strategy).build();
+
+        Assertions.assertSame(strategy, newCache.getEvictionStrategy(), "Returned strategy should be the same instance");
+    }
+
+    @Test
+    void testDefaultStrategyIsImmediateEvictionStrategy() {
+        FIFOCache<String, String> newCache = new FIFOCache.Builder<String, String>(5).defaultTTL(1000).build();
+
+        Assertions.assertTrue(newCache.getEvictionStrategy() instanceof FIFOCache.ImmediateEvictionStrategy<String, String>, "Default strategy should be ImmediateEvictionStrategyStrategy");
+    }
+
+    @Test
+    void testGetEvictionStrategyIsNotNull() {
+        FIFOCache<String, String> newCache = new FIFOCache.Builder<String, String>(5).build();
+
+        Assertions.assertNotNull(newCache.getEvictionStrategy(), "Eviction strategy should never be null");
+    }
+
+    @Test
+    void testRemoveKeyRemovesExistingKey() {
+        cache.put("A", "Alpha");
+        cache.put("B", "Beta");
+
+        Assertions.assertEquals("Alpha", cache.get("A"));
+        Assertions.assertEquals("Beta", cache.get("B"));
+
+        String removed = cache.removeKey("A");
+        Assertions.assertEquals("Alpha", removed);
+
+        Assertions.assertNull(cache.get("A"));
+        Assertions.assertEquals(1, cache.size());
+    }
+
+    @Test
+    void testRemoveKeyReturnsNullIfKeyNotPresent() {
+        cache.put("X", "X-ray");
+
+        Assertions.assertNull(cache.removeKey("NonExistent"));
+        Assertions.assertEquals(1, cache.size());
+    }
+
+    @Test
+    void testRemoveKeyHandlesExpiredEntry() throws InterruptedException {
+        FIFOCache<String, String> expiringCache = new FIFOCache.Builder<String, String>(2).defaultTTL(100).evictionStrategy(new FIFOCache.ImmediateEvictionStrategy<>()).build();
+
+        expiringCache.put("T", "Temporary");
+
+        Thread.sleep(200);
+
+        String removed = expiringCache.removeKey("T");
+        Assertions.assertEquals("Temporary", removed);
+        Assertions.assertNull(expiringCache.get("T"));
+    }
+
+    @Test
+    void testRemoveKeyThrowsIfKeyIsNull() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.removeKey(null));
+    }
+
+    @Test
+    void testRemoveKeyTriggersEvictionListener() {
+        AtomicInteger evictedCount = new AtomicInteger();
+
+        FIFOCache<String, String> localCache = new FIFOCache.Builder<String, String>(2).evictionListener((key, value) -> evictedCount.incrementAndGet()).build();
+
+        localCache.put("A", "Apple");
+        localCache.put("B", "Banana");
+
+        localCache.removeKey("A");
+
+        Assertions.assertEquals(1, evictedCount.get(), "Eviction listener should have been called once");
+    }
+
+    @Test
+    void testRemoveKeyDoestNotAffectOtherKeys() {
+        cache.put("A", "Alpha");
+        cache.put("B", "Beta");
+        cache.put("C", "Gamma");
+
+        cache.removeKey("B");
+
+        Assertions.assertEquals("Alpha", cache.get("A"));
+        Assertions.assertNull(cache.get("B"));
+        Assertions.assertEquals("Gamma", cache.get("C"));
+    }
+
+    @Test
+    void testEvictionListenerExceptionDoesNotPropagate() {
+        FIFOCache<String, String> localCache = new FIFOCache.Builder<String, String>(1).evictionListener((key, value) -> { throw new RuntimeException(); }).build();
+
+        localCache.put("A", "Apple");
+
+        Assertions.assertDoesNotThrow(() -> localCache.put("B", "Beta"));
+    }
+
+    @Test
+    void testGetKeysReturnsAllFreshKeys() {
+        cache.put("A", "Alpha");
+        cache.put("B", "Beta");
+        cache.put("G", "Gamma");
+
+        Set<String> expectedKeys = Set.of("A", "B", "G");
+        Assertions.assertEquals(expectedKeys, cache.getAllKeys());
+    }
+
+    @Test
+    void testGetKeysIgnoresExpiredKeys() throws InterruptedException {
+        cache.put("A", "Alpha");
+        cache.put("B", "Beta");
+        cache.put("G", "Gamma", 100);
+
+        Set<String> expectedKeys = Set.of("A", "B");
+        Thread.sleep(200);
+        Assertions.assertEquals(expectedKeys, cache.getAllKeys());
+    }
+
+    @Test
+    void testClearRemovesAllEntries() {
+        cache.put("A", "Alpha");
+        cache.put("B", "Beta");
+        cache.put("G", "Gamma");
+
+        cache.clear();
+        Assertions.assertEquals(0, cache.size());
+    }
+}

From 9b4dec0b06470bff898c108fe2ed19927c93e08c Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Sat, 5 Jul 2025 17:07:10 +0200
Subject: [PATCH 0844/1338] Update DIRECTORY.md (#6344)

Co-authored-by: siriak <siriak@users.noreply.github.com>
---
 DIRECTORY.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 5a75847218b5..9697dbc09869 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -128,6 +128,7 @@
           - 📁 **buffers**
             - 📄 [CircularBuffer](src/main/java/com/thealgorithms/datastructures/buffers/CircularBuffer.java)
           - 📁 **caches**
+            - 📄 [FIFOCache](src/main/java/com/thealgorithms/datastructures/caches/FIFOCache.java)
             - 📄 [LFUCache](src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java)
             - 📄 [LRUCache](src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java)
             - 📄 [MRUCache](src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java)
@@ -872,6 +873,7 @@
           - 📁 **buffers**
             - 📄 [CircularBufferTest](src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java)
           - 📁 **caches**
+            - 📄 [FIFOCacheTest](src/test/java/com/thealgorithms/datastructures/caches/FIFOCacheTest.java)
             - 📄 [LFUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java)
             - 📄 [LRUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java)
             - 📄 [MRUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java)

From 350f1496573c218f1d3796ed80811d4f46060125 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sun, 6 Jul 2025 19:03:02 +0200
Subject: [PATCH 0845/1338] Add parameterized tests for BitSwap (#6347)

---
 .../bitmanipulation/BitSwap.java              | 19 +++++-
 .../bitmanipulation/BitSwapTest.java          | 63 ++++++++++++++++---
 2 files changed, 73 insertions(+), 9 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java b/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java
index 40b3097b1276..d8c207567ba6 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java
@@ -1,12 +1,27 @@
 package com.thealgorithms.bitmanipulation;
 
+/**
+ * Utility class for performing bit-swapping operations on integers.
+ * This class cannot be instantiated.
+ */
 public final class BitSwap {
     private BitSwap() {
     }
-    /*
-     * @brief Swaps the bits at the position posA and posB from data
+
+    /**
+     * Swaps two bits at specified positions in an integer.
+     *
+     * @param data The input integer whose bits need to be swapped
+     * @param posA The position of the first bit (0-based, from least significant)
+     * @param posB The position of the second bit (0-based, from least significant)
+     * @return The modified value with swapped bits
+     * @throws IllegalArgumentException if either position is negative or ≥ 32
      */
     public static int bitSwap(int data, final int posA, final int posB) {
+        if (posA < 0 || posA >= Integer.SIZE || posB < 0 || posB >= Integer.SIZE) {
+            throw new IllegalArgumentException("Bit positions must be between 0 and 31");
+        }
+
         if (SingleBitOperations.getBit(data, posA) != SingleBitOperations.getBit(data, posB)) {
             data ^= (1 << posA) ^ (1 << posB);
         }
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java b/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java
index 40de770e0c66..9d888d056453 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java
@@ -1,13 +1,62 @@
 package com.thealgorithms.bitmanipulation;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import org.junit.jupiter.api.Test;
-public class BitSwapTest {
-    @Test
-    void testHighestSetBit() {
-        assertEquals(3, BitSwap.bitSwap(3, 0, 1));
-        assertEquals(5, BitSwap.bitSwap(6, 0, 1));
-        assertEquals(7, BitSwap.bitSwap(7, 1, 1));
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class BitSwapTest {
+
+    @ParameterizedTest(name = "Additional cases: data={0}, posA={1}, posB={2} -> expected={3}")
+    @MethodSource("provideAdditionalCases")
+    void testAdditionalCases(int data, int posA, int posB, int expected) {
+        assertEquals(expected, BitSwap.bitSwap(data, posA, posB));
+    }
+
+    @ParameterizedTest(name = "Swap different bits: data={0}, posA={1}, posB={2} -> expected={3}")
+    @MethodSource("provideDifferentBitsCases")
+    void swapDifferentBits(int data, int posA, int posB, int expected) {
+        assertEquals(expected, BitSwap.bitSwap(data, posA, posB));
+    }
+
+    @ParameterizedTest(name = "Swap same bits: data={0}, posA={1}, posB={2} should not change")
+    @MethodSource("provideSameBitsCases")
+    void swapSameBits(int data, int posA, int posB) {
+        assertEquals(data, BitSwap.bitSwap(data, posA, posB));
+    }
+
+    @ParameterizedTest(name = "Edge cases: data={0}, posA={1}, posB={2} -> expected={3}")
+    @MethodSource("provideEdgeCases")
+    void testEdgeCases(int data, int posA, int posB, int expected) {
+        assertEquals(expected, BitSwap.bitSwap(data, posA, posB));
+    }
+
+    @ParameterizedTest(name = "Invalid positions: data={0}, posA={1}, posB={2} should throw")
+    @MethodSource("provideInvalidPositions")
+    void invalidPositionThrowsException(int data, int posA, int posB) {
+        assertThrows(IllegalArgumentException.class, () -> BitSwap.bitSwap(data, posA, posB));
+    }
+
+    static Stream<Arguments> provideAdditionalCases() {
+        return Stream.of(Arguments.of(3, 0, 1, 3), Arguments.of(6, 0, 1, 5), Arguments.of(7, 1, 1, 7));
+    }
+
+    static Stream<Arguments> provideDifferentBitsCases() {
+        return Stream.of(Arguments.of(0b01, 0, 1, 0b10));
+    }
+
+    static Stream<Arguments> provideSameBitsCases() {
+        return Stream.of(Arguments.of(0b111, 0, 2), Arguments.of(0b0, 1, 3), Arguments.of(0b1010, 1, 3), Arguments.of(-1, 5, 5));
+    }
+
+    static Stream<Arguments> provideEdgeCases() {
+        return Stream.of(Arguments.of(Integer.MIN_VALUE, 31, 0, 1), Arguments.of(0, 0, 31, 0));
+    }
+
+    static Stream<Arguments> provideInvalidPositions() {
+        return Stream.of(Arguments.of(0, -1, 0), Arguments.of(0, 0, 32), Arguments.of(0, -5, 33), Arguments.of(0, Integer.MIN_VALUE, Integer.MAX_VALUE));
     }
 }

From 4b6006c87656d718e5f928865758a6e4908657e1 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sun, 6 Jul 2025 23:19:50 +0200
Subject: [PATCH 0846/1338] refactor: improve code and test coverage for
 `MapReduce` example (#6348)

refactor: improve code and test coverage for MapReduce example
---
 .../com/thealgorithms/misc/MapReduce.java     | 47 +++++++++----------
 .../com/thealgorithms/misc/MapReduceTest.java | 22 +++------
 2 files changed, 30 insertions(+), 39 deletions(-)

diff --git a/src/main/java/com/thealgorithms/misc/MapReduce.java b/src/main/java/com/thealgorithms/misc/MapReduce.java
index c076957344f9..d98b2ee2dd03 100644
--- a/src/main/java/com/thealgorithms/misc/MapReduce.java
+++ b/src/main/java/com/thealgorithms/misc/MapReduce.java
@@ -7,35 +7,34 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
-/*
-* MapReduce is a programming model for processing and generating large data sets with a parallel,
-distributed algorithm on a cluster.
-* It has two main steps: the Map step, where the data is divided into smaller chunks and processed in parallel,
-and the Reduce step, where the results from the Map step are combined to produce the final output.
-* Wikipedia link : https://en.wikipedia.org/wiki/MapReduce
-*/
-
+/**
+ * MapReduce is a programming model for processing and generating large data sets
+ * using a parallel, distributed algorithm on a cluster.
+ * It consists of two main phases:
+ * - Map: the input data is split into smaller chunks and processed in parallel.
+ * - Reduce: the results from the Map phase are aggregated to produce the final output.
+ *
+ * See also: https://en.wikipedia.org/wiki/MapReduce
+ */
 public final class MapReduce {
+
     private MapReduce() {
     }
-    /*
-     *Counting all the words frequency within a sentence.
-     */
-    public static String mapreduce(String sentence) {
-        List<String> wordList = Arrays.stream(sentence.split(" ")).toList();
 
-        // Map step
-        Map<String, Long> wordCounts = wordList.stream().collect(Collectors.groupingBy(Function.identity(), LinkedHashMap::new, Collectors.counting()));
-
-        // Reduce step
-        StringBuilder result = new StringBuilder();
-        wordCounts.forEach((word, count) -> result.append(word).append(": ").append(count).append(","));
+    /**
+     * Counts the frequency of each word in a given sentence using a simple MapReduce-style approach.
+     *
+     * @param sentence the input sentence
+     * @return a string representing word frequencies in the format "word: count,word: count,..."
+     */
+    public static String countWordFrequencies(String sentence) {
+        // Map phase: split the sentence into words
+        List<String> words = Arrays.asList(sentence.trim().split("\\s+"));
 
-        // Removing the last ',' if it exists
-        if (!result.isEmpty()) {
-            result.setLength(result.length() - 1);
-        }
+        // Group and count occurrences of each word, maintain insertion order
+        Map<String, Long> wordCounts = words.stream().collect(Collectors.groupingBy(Function.identity(), LinkedHashMap::new, Collectors.counting()));
 
-        return result.toString();
+        // Reduce phase: format the result
+        return wordCounts.entrySet().stream().map(entry -> entry.getKey() + ": " + entry.getValue()).collect(Collectors.joining(","));
     }
 }
diff --git a/src/test/java/com/thealgorithms/misc/MapReduceTest.java b/src/test/java/com/thealgorithms/misc/MapReduceTest.java
index c79c40701cc1..748dd0a563cf 100644
--- a/src/test/java/com/thealgorithms/misc/MapReduceTest.java
+++ b/src/test/java/com/thealgorithms/misc/MapReduceTest.java
@@ -2,22 +2,14 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class MapReduceTest {
-    @Test
-    public void testMapReduceWithSingleWordSentence() {
-        String oneWordSentence = "Hactober";
-        String result = MapReduce.mapreduce(oneWordSentence);
-
-        assertEquals("Hactober: 1", result);
-    }
-
-    @Test
-    public void testMapReduceWithMultipleWordSentence() {
-        String multipleWordSentence = "I Love Love HactoberFest";
-        String result = MapReduce.mapreduce(multipleWordSentence);
-
-        assertEquals("I: 1,Love: 2,HactoberFest: 1", result);
+    @ParameterizedTest
+    @CsvSource({"'hello world', 'hello: 1,world: 1'", "'one one two', 'one: 2,two: 1'", "'a a a a', 'a: 4'", "'  spaced  out  ', 'spaced: 1,out: 1'"})
+    void testCountWordFrequencies(String input, String expected) {
+        String result = MapReduce.countWordFrequencies(input);
+        assertEquals(expected, result);
     }
 }

From 8512f127ce2c1a32a7909dcca1f475ccaf73e49e Mon Sep 17 00:00:00 2001
From: pushkar0406 <136320165+pushkar0406@users.noreply.github.com>
Date: Mon, 7 Jul 2025 16:52:40 +0530
Subject: [PATCH 0847/1338] Fix the formatting issue with clang-format (#6346)

---
 .../sorts/AdaptiveMergeSortTest.java          | 89 ++++++++++++++++++
 .../com/thealgorithms/sorts/BogoSortTest.java | 84 +++++++++++++++++
 .../thealgorithms/sorts/BubbleSortTest.java   | 84 +++++++++++++++++
 .../thealgorithms/sorts/GnomeSortTest.java    | 90 +++++++++++++++++++
 .../sorts/InsertionSortTest.java              | 84 +++++++++++++++++
 .../com/thealgorithms/sorts/SlowSortTest.java | 84 +++++++++++++++++
 6 files changed, 515 insertions(+)

diff --git a/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java b/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java
index 9d94b165d81b..8cb401802c4b 100644
--- a/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
+import java.util.Objects;
 import org.junit.jupiter.api.Test;
 
 public class AdaptiveMergeSortTest {
@@ -50,4 +51,92 @@ public void testSortSingleElement() {
         Integer[] result = adaptiveMergeSort.sort(input);
         assertArrayEquals(expected, result);
     }
+
+    @Test
+    public void testSortAlreadySortedArray() {
+        AdaptiveMergeSort adaptiveMergeSort = new AdaptiveMergeSort();
+        Integer[] inputArray = {-12, -6, -3, 0, 2, 2, 13, 46};
+        Integer[] outputArray = adaptiveMergeSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void testSortReversedSortedArray() {
+        AdaptiveMergeSort adaptiveMergeSort = new AdaptiveMergeSort();
+        Integer[] inputArray = {46, 13, 2, 2, 0, -3, -6, -12};
+        Integer[] outputArray = adaptiveMergeSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void testSortAllEqualArray() {
+        AdaptiveMergeSort adaptiveMergeSort = new AdaptiveMergeSort();
+        Integer[] inputArray = {2, 2, 2, 2, 2};
+        Integer[] outputArray = adaptiveMergeSort.sort(inputArray);
+        Integer[] expectedOutput = {2, 2, 2, 2, 2};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void testSortMixedCaseStrings() {
+        AdaptiveMergeSort adaptiveMergeSort = new AdaptiveMergeSort();
+        String[] inputArray = {"banana", "Apple", "apple", "Banana"};
+        String[] expectedOutput = {"Apple", "Banana", "apple", "banana"};
+        String[] outputArray = adaptiveMergeSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
+
+    /**
+     * Custom Comparable class for testing.
+     **/
+    static class Person implements Comparable<Person> {
+        String name;
+        int age;
+
+        Person(String name, int age) {
+            this.name = name;
+            this.age = age;
+        }
+
+        @Override
+        public int compareTo(Person o) {
+            return Integer.compare(this.age, o.age);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            Person person = (Person) o;
+            return age == person.age && Objects.equals(name, person.name);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(name, age);
+        }
+    }
+
+    @Test
+    public void testSortCustomObjects() {
+        AdaptiveMergeSort adaptiveMergeSort = new AdaptiveMergeSort();
+        Person[] inputArray = {
+            new Person("Alice", 32),
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+        };
+        Person[] expectedOutput = {
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+            new Person("Alice", 32),
+        };
+        Person[] outputArray = adaptiveMergeSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/BogoSortTest.java b/src/test/java/com/thealgorithms/sorts/BogoSortTest.java
index 3ebfb7a305b0..dc4f9e1c25bb 100644
--- a/src/test/java/com/thealgorithms/sorts/BogoSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/BogoSortTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
+import java.util.Objects;
 import org.junit.jupiter.api.Test;
 
 public class BogoSortTest {
@@ -63,4 +64,87 @@ public void bogoSortDuplicateStringArray() {
         String[] expectedOutput = {"a", "b", "b", "c", "d", "d", "h", "s"};
         assertArrayEquals(outputArray, expectedOutput);
     }
+
+    @Test
+    public void bogoSortAlreadySortedArray() {
+        Integer[] inputArray = {-12, -6, -3, 0, 2, 2, 13, 46};
+        Integer[] outputArray = bogoSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void bogoSortReversedSortedArray() {
+        Integer[] inputArray = {46, 13, 2, 2, 0, -3, -6, -12};
+        Integer[] outputArray = bogoSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void bogoSortAllEqualArray() {
+        Integer[] inputArray = {2, 2, 2, 2, 2};
+        Integer[] outputArray = bogoSort.sort(inputArray);
+        Integer[] expectedOutput = {2, 2, 2, 2, 2};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void bogoSortMixedCaseStrings() {
+        String[] inputArray = {"banana", "Apple", "apple", "Banana"};
+        String[] expectedOutput = {"Apple", "Banana", "apple", "banana"};
+        String[] outputArray = bogoSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
+
+    /**
+     * Custom Comparable class for testing.
+     **/
+    static class Person implements Comparable<Person> {
+        String name;
+        int age;
+
+        Person(String name, int age) {
+            this.name = name;
+            this.age = age;
+        }
+
+        @Override
+        public int compareTo(Person o) {
+            return Integer.compare(this.age, o.age);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            Person person = (Person) o;
+            return age == person.age && Objects.equals(name, person.name);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(name, age);
+        }
+    }
+
+    @Test
+    public void bogoSortCustomObjects() {
+        Person[] inputArray = {
+            new Person("Alice", 32),
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+        };
+        Person[] expectedOutput = {
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+            new Person("Alice", 32),
+        };
+        Person[] outputArray = bogoSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/BubbleSortTest.java b/src/test/java/com/thealgorithms/sorts/BubbleSortTest.java
index 8690a3f5435c..3b99dca13b06 100644
--- a/src/test/java/com/thealgorithms/sorts/BubbleSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/BubbleSortTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
+import java.util.Objects;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -91,4 +92,87 @@ public void bubbleSortStringArray() {
         };
         assertArrayEquals(outputArray, expectedOutput);
     }
+
+    @Test
+    public void bubbleSortAlreadySortedArray() {
+        Integer[] inputArray = {-12, -6, -3, 0, 2, 2, 13, 46};
+        Integer[] outputArray = bubbleSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void bubbleSortReversedSortedArray() {
+        Integer[] inputArray = {46, 13, 2, 2, 0, -3, -6, -12};
+        Integer[] outputArray = bubbleSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void bubbleSortAllEqualArray() {
+        Integer[] inputArray = {2, 2, 2, 2, 2};
+        Integer[] outputArray = bubbleSort.sort(inputArray);
+        Integer[] expectedOutput = {2, 2, 2, 2, 2};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void bubbleSortMixedCaseStrings() {
+        String[] inputArray = {"banana", "Apple", "apple", "Banana"};
+        String[] expectedOutput = {"Apple", "Banana", "apple", "banana"};
+        String[] outputArray = bubbleSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
+
+    /**
+     * Custom Comparable class for testing.
+     **/
+    static class Person implements Comparable<Person> {
+        String name;
+        int age;
+
+        Person(String name, int age) {
+            this.name = name;
+            this.age = age;
+        }
+
+        @Override
+        public int compareTo(Person o) {
+            return Integer.compare(this.age, o.age);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            Person person = (Person) o;
+            return age == person.age && Objects.equals(name, person.name);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(name, age);
+        }
+    }
+
+    @Test
+    public void bubbleSortCustomObjects() {
+        Person[] inputArray = {
+            new Person("Alice", 32),
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+        };
+        Person[] expectedOutput = {
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+            new Person("Alice", 32),
+        };
+        Person[] outputArray = bubbleSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/GnomeSortTest.java b/src/test/java/com/thealgorithms/sorts/GnomeSortTest.java
index d86546472580..1d875d1fad0d 100644
--- a/src/test/java/com/thealgorithms/sorts/GnomeSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/GnomeSortTest.java
@@ -1,7 +1,9 @@
 package com.thealgorithms.sorts;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
+import java.util.Objects;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
@@ -79,4 +81,92 @@ public void gnomeSortDuplicateStringArray() {
         gnomeSort.sort(inputArray);
         assertThat(inputArray).isEqualTo(expectedOutput);
     }
+
+    @Test
+    @DisplayName("GnomeSort for sorted Array")
+    public void testSortAlreadySortedArray() {
+        Integer[] inputArray = {-12, -6, -3, 0, 2, 2, 13, 46};
+        Integer[] outputArray = gnomeSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    @DisplayName("GnomeSort for reversed sorted Array")
+    public void testSortReversedSortedArray() {
+        Integer[] inputArray = {46, 13, 2, 2, 0, -3, -6, -12};
+        Integer[] outputArray = gnomeSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    @DisplayName("GnomeSort for All equal Array")
+    public void testSortAllEqualArray() {
+        Integer[] inputArray = {2, 2, 2, 2, 2};
+        Integer[] outputArray = gnomeSort.sort(inputArray);
+        Integer[] expectedOutput = {2, 2, 2, 2, 2};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    @DisplayName("GnomeSort String Array with mixed cases")
+    public void testSortMixedCaseStrings() {
+        String[] inputArray = {"banana", "Apple", "apple", "Banana"};
+        String[] expectedOutput = {"Apple", "Banana", "apple", "banana"};
+        String[] outputArray = gnomeSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
+
+    /**
+     * Custom Comparable class for testing.
+     **/
+    static class Person implements Comparable<Person> {
+        String name;
+        int age;
+
+        Person(String name, int age) {
+            this.name = name;
+            this.age = age;
+        }
+
+        @Override
+        public int compareTo(Person o) {
+            return Integer.compare(this.age, o.age);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            Person person = (Person) o;
+            return age == person.age && Objects.equals(name, person.name);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(name, age);
+        }
+    }
+
+    @Test
+    @DisplayName("GnomeSort Custom Object Array")
+    public void testSortCustomObjects() {
+        Person[] inputArray = {
+            new Person("Alice", 32),
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+        };
+        Person[] expectedOutput = {
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+            new Person("Alice", 32),
+        };
+        Person[] outputArray = gnomeSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java b/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java
index 78744973355d..32a2a807295b 100644
--- a/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/InsertionSortTest.java
@@ -3,6 +3,7 @@
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.util.Objects;
 import java.util.function.Function;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -111,4 +112,87 @@ private void testWithRandomArray(Function<Double[], Double[]> sortAlgorithm) {
         Double[] sorted = sortAlgorithm.apply(array);
         assertTrue(SortUtils.isSorted(sorted));
     }
+
+    @Test
+    public void testSortAlreadySortedArray() {
+        Integer[] inputArray = {-12, -6, -3, 0, 2, 2, 13, 46};
+        Integer[] outputArray = insertionSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void testSortReversedSortedArray() {
+        Integer[] inputArray = {46, 13, 2, 2, 0, -3, -6, -12};
+        Integer[] outputArray = insertionSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void testSortAllEqualArray() {
+        Integer[] inputArray = {2, 2, 2, 2, 2};
+        Integer[] outputArray = insertionSort.sort(inputArray);
+        Integer[] expectedOutput = {2, 2, 2, 2, 2};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void testSortMixedCaseStrings() {
+        String[] inputArray = {"banana", "Apple", "apple", "Banana"};
+        String[] expectedOutput = {"Apple", "Banana", "apple", "banana"};
+        String[] outputArray = insertionSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
+
+    /**
+     * Custom Comparable class for testing.
+     **/
+    static class Person implements Comparable<Person> {
+        String name;
+        int age;
+
+        Person(String name, int age) {
+            this.name = name;
+            this.age = age;
+        }
+
+        @Override
+        public int compareTo(Person o) {
+            return Integer.compare(this.age, o.age);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            Person person = (Person) o;
+            return age == person.age && Objects.equals(name, person.name);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(name, age);
+        }
+    }
+
+    @Test
+    public void testSortCustomObjects() {
+        Person[] inputArray = {
+            new Person("Alice", 32),
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+        };
+        Person[] expectedOutput = {
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+            new Person("Alice", 32),
+        };
+        Person[] outputArray = insertionSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
 }
diff --git a/src/test/java/com/thealgorithms/sorts/SlowSortTest.java b/src/test/java/com/thealgorithms/sorts/SlowSortTest.java
index d4d9eaa1c275..5fbdf8477092 100644
--- a/src/test/java/com/thealgorithms/sorts/SlowSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/SlowSortTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
+import java.util.Objects;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -76,4 +77,87 @@ public void slowSortStringSymbolArray() {
         String[] expectedOutput = {"(a", "(b", ")", "a", "au", "auk", "auk", "bhy", "cba", "cba", "cbf", "á", "ó"};
         assertArrayEquals(outputArray, expectedOutput);
     }
+
+    @Test
+    public void testSortAlreadySortedArray() {
+        Integer[] inputArray = {-12, -6, -3, 0, 2, 2, 13, 46};
+        Integer[] outputArray = slowSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void testSortReversedSortedArray() {
+        Integer[] inputArray = {46, 13, 2, 2, 0, -3, -6, -12};
+        Integer[] outputArray = slowSort.sort(inputArray);
+        Integer[] expectedOutput = {-12, -6, -3, 0, 2, 2, 13, 46};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void testSortAllEqualArray() {
+        Integer[] inputArray = {2, 2, 2, 2, 2};
+        Integer[] outputArray = slowSort.sort(inputArray);
+        Integer[] expectedOutput = {2, 2, 2, 2, 2};
+        assertArrayEquals(outputArray, expectedOutput);
+    }
+
+    @Test
+    public void testSortMixedCaseStrings() {
+        String[] inputArray = {"banana", "Apple", "apple", "Banana"};
+        String[] expectedOutput = {"Apple", "Banana", "apple", "banana"};
+        String[] outputArray = slowSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
+
+    /**
+     * Custom Comparable class for testing.
+     **/
+    static class Person implements Comparable<Person> {
+        String name;
+        int age;
+
+        Person(String name, int age) {
+            this.name = name;
+            this.age = age;
+        }
+
+        @Override
+        public int compareTo(Person o) {
+            return Integer.compare(this.age, o.age);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            Person person = (Person) o;
+            return age == person.age && Objects.equals(name, person.name);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(name, age);
+        }
+    }
+
+    @Test
+    public void testSortCustomObjects() {
+        Person[] inputArray = {
+            new Person("Alice", 32),
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+        };
+        Person[] expectedOutput = {
+            new Person("Bob", 25),
+            new Person("Charlie", 28),
+            new Person("Alice", 32),
+        };
+        Person[] outputArray = slowSort.sort(inputArray);
+        assertArrayEquals(expectedOutput, outputArray);
+    }
 }

From 2f5bc8c24281d69872fd645e5cb908144f1f21a1 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Mon, 7 Jul 2025 13:29:10 +0200
Subject: [PATCH 0848/1338] refactor: improve median calculator class design
 and readability (#6349)

---
 .../misc/MedianOfRunningArray.java            | 82 ++++++++++++-------
 .../misc/MedianOfRunningArrayTest.java        | 80 +++++++++---------
 2 files changed, 93 insertions(+), 69 deletions(-)

diff --git a/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java b/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
index 62013ee31183..95f86f63f720 100644
--- a/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
+++ b/src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
@@ -4,50 +4,74 @@
 import java.util.PriorityQueue;
 
 /**
- * @author shrutisheoran
+ * A generic abstract class to compute the median of a dynamically growing stream of numbers.
+ *
+ * @param <T> the number type, must extend Number and be Comparable
+ *
+ * Usage:
+ * Extend this class and implement {@code calculateAverage(T a, T b)} to define how averaging is done.
  */
 public abstract class MedianOfRunningArray<T extends Number & Comparable<T>> {
 
-    private PriorityQueue<T> maxHeap;
-    private PriorityQueue<T> minHeap;
+    private final PriorityQueue<T> maxHeap; // Lower half (max-heap)
+    private final PriorityQueue<T> minHeap; // Upper half (min-heap)
 
-    // Constructor
     public MedianOfRunningArray() {
-        this.maxHeap = new PriorityQueue<>(Collections.reverseOrder()); // Max Heap
-        this.minHeap = new PriorityQueue<>(); // Min Heap
+        this.maxHeap = new PriorityQueue<>(Collections.reverseOrder());
+        this.minHeap = new PriorityQueue<>();
     }
 
-    /*
-      Inserting lower half of array to max Heap
-      and upper half to min heap
+    /**
+     * Inserts a new number into the data structure.
+     *
+     * @param element the number to insert
      */
-    public void insert(final T e) {
-        if (!minHeap.isEmpty() && e.compareTo(minHeap.peek()) < 0) {
-            maxHeap.offer(e);
-            if (maxHeap.size() > minHeap.size() + 1) {
-                minHeap.offer(maxHeap.poll());
-            }
+    public final void insert(final T element) {
+        if (!minHeap.isEmpty() && element.compareTo(minHeap.peek()) < 0) {
+            maxHeap.offer(element);
+            balanceHeapsIfNeeded();
         } else {
-            minHeap.offer(e);
-            if (minHeap.size() > maxHeap.size() + 1) {
-                maxHeap.offer(minHeap.poll());
-            }
+            minHeap.offer(element);
+            balanceHeapsIfNeeded();
         }
     }
 
-    /*
-      Returns median at any given point
+    /**
+     * Returns the median of the current elements.
+     *
+     * @return the median value
+     * @throws IllegalArgumentException if no elements have been inserted
      */
-    public T median() {
+    public final T getMedian() {
         if (maxHeap.isEmpty() && minHeap.isEmpty()) {
-            throw new IllegalArgumentException("Enter at least 1 element, Median of empty list is not defined!");
-        } else if (maxHeap.size() == minHeap.size()) {
-            T maxHeapTop = maxHeap.peek();
-            T minHeapTop = minHeap.peek();
-            return calculateAverage(maxHeapTop, minHeapTop);
+            throw new IllegalArgumentException("Median is undefined for an empty data set.");
         }
-        return maxHeap.size() > minHeap.size() ? maxHeap.peek() : minHeap.peek();
+
+        if (maxHeap.size() == minHeap.size()) {
+            return calculateAverage(maxHeap.peek(), minHeap.peek());
+        }
+
+        return (maxHeap.size() > minHeap.size()) ? maxHeap.peek() : minHeap.peek();
     }
 
-    public abstract T calculateAverage(T a, T b);
+    /**
+     * Calculates the average between two values.
+     * Concrete subclasses must define how averaging works (e.g., for Integer, Double, etc.).
+     *
+     * @param a first number
+     * @param b second number
+     * @return the average of a and b
+     */
+    protected abstract T calculateAverage(T a, T b);
+
+    /**
+     * Balances the two heaps so that their sizes differ by at most 1.
+     */
+    private void balanceHeapsIfNeeded() {
+        if (maxHeap.size() > minHeap.size() + 1) {
+            minHeap.offer(maxHeap.poll());
+        } else if (minHeap.size() > maxHeap.size() + 1) {
+            maxHeap.offer(minHeap.poll());
+        }
+    }
 }
diff --git a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
index e64ae1b741b6..f41953035846 100644
--- a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
+++ b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
@@ -11,12 +11,12 @@
  */
 
 public class MedianOfRunningArrayTest {
-    private static final String EXCEPTION_MESSAGE = "Enter at least 1 element, Median of empty list is not defined!";
+    private static final String EXCEPTION_MESSAGE = "Median is undefined for an empty data set.";
 
     @Test
     public void testWhenInvalidInoutProvidedShouldThrowException() {
         var stream = new MedianOfRunningArrayInteger();
-        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> stream.median());
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, stream::getMedian);
         assertEquals(exception.getMessage(), EXCEPTION_MESSAGE);
     }
 
@@ -24,68 +24,68 @@ public void testWhenInvalidInoutProvidedShouldThrowException() {
     public void testWithNegativeValues() {
         var stream = new MedianOfRunningArrayInteger();
         stream.insert(-1);
-        assertEquals(-1, stream.median());
+        assertEquals(-1, stream.getMedian());
         stream.insert(-2);
-        assertEquals(-1, stream.median());
+        assertEquals(-1, stream.getMedian());
         stream.insert(-3);
-        assertEquals(-2, stream.median());
+        assertEquals(-2, stream.getMedian());
     }
 
     @Test
     public void testWithSingleValues() {
         var stream = new MedianOfRunningArrayInteger();
         stream.insert(-1);
-        assertEquals(-1, stream.median());
+        assertEquals(-1, stream.getMedian());
     }
 
     @Test
     public void testWithRandomValues() {
         var stream = new MedianOfRunningArrayInteger();
         stream.insert(10);
-        assertEquals(10, stream.median());
+        assertEquals(10, stream.getMedian());
 
         stream.insert(5);
-        assertEquals(7, stream.median());
+        assertEquals(7, stream.getMedian());
 
         stream.insert(20);
-        assertEquals(10, stream.median());
+        assertEquals(10, stream.getMedian());
 
         stream.insert(15);
-        assertEquals(12, stream.median());
+        assertEquals(12, stream.getMedian());
 
         stream.insert(25);
-        assertEquals(15, stream.median());
+        assertEquals(15, stream.getMedian());
 
         stream.insert(30);
-        assertEquals(17, stream.median());
+        assertEquals(17, stream.getMedian());
 
         stream.insert(35);
-        assertEquals(20, stream.median());
+        assertEquals(20, stream.getMedian());
 
         stream.insert(1);
-        assertEquals(17, stream.median());
+        assertEquals(17, stream.getMedian());
     }
 
     @Test
     public void testWithNegativeAndPositiveValues() {
         var stream = new MedianOfRunningArrayInteger();
         stream.insert(-1);
-        assertEquals(-1, stream.median());
+        assertEquals(-1, stream.getMedian());
         stream.insert(2);
-        assertEquals(0, stream.median());
+        assertEquals(0, stream.getMedian());
         stream.insert(-3);
-        assertEquals(-1, stream.median());
+        assertEquals(-1, stream.getMedian());
     }
 
     @Test
     public void testWithDuplicateValues() {
         var stream = new MedianOfRunningArrayInteger();
         stream.insert(-1);
-        assertEquals(-1, stream.median());
+        assertEquals(-1, stream.getMedian());
         stream.insert(-1);
-        assertEquals(-1, stream.median());
+        assertEquals(-1, stream.getMedian());
         stream.insert(-1);
-        assertEquals(-1, stream.median());
+        assertEquals(-1, stream.getMedian());
     }
 
     @Test
@@ -98,20 +98,20 @@ public void testWithDuplicateValuesB() {
         stream.insert(20);
         stream.insert(0);
         stream.insert(50);
-        assertEquals(10, stream.median());
+        assertEquals(10, stream.getMedian());
     }
 
     @Test
     public void testWithLargeValues() {
         var stream = new MedianOfRunningArrayInteger();
         stream.insert(1000000);
-        assertEquals(1000000, stream.median());
+        assertEquals(1000000, stream.getMedian());
         stream.insert(12000);
-        assertEquals(506000, stream.median());
+        assertEquals(506000, stream.getMedian());
         stream.insert(15000000);
-        assertEquals(1000000, stream.median());
+        assertEquals(1000000, stream.getMedian());
         stream.insert(2300000);
-        assertEquals(1650000, stream.median());
+        assertEquals(1650000, stream.getMedian());
     }
 
     @Test
@@ -120,7 +120,7 @@ public void testWithLargeCountOfValues() {
         for (int i = 1; i <= 1000; i++) {
             stream.insert(i);
         }
-        assertEquals(500, stream.median());
+        assertEquals(500, stream.getMedian());
     }
 
     @Test
@@ -129,7 +129,7 @@ public void testWithThreeValuesInDescendingOrder() {
         stream.insert(30);
         stream.insert(20);
         stream.insert(10);
-        assertEquals(20, stream.median());
+        assertEquals(20, stream.getMedian());
     }
 
     @Test
@@ -138,7 +138,7 @@ public void testWithThreeValuesInOrder() {
         stream.insert(10);
         stream.insert(20);
         stream.insert(30);
-        assertEquals(20, stream.median());
+        assertEquals(20, stream.getMedian());
     }
 
     @Test
@@ -147,7 +147,7 @@ public void testWithThreeValuesNotInOrderA() {
         stream.insert(30);
         stream.insert(10);
         stream.insert(20);
-        assertEquals(20, stream.median());
+        assertEquals(20, stream.getMedian());
     }
 
     @Test
@@ -156,46 +156,46 @@ public void testWithThreeValuesNotInOrderB() {
         stream.insert(20);
         stream.insert(10);
         stream.insert(30);
-        assertEquals(20, stream.median());
+        assertEquals(20, stream.getMedian());
     }
 
     @Test
     public void testWithFloatValues() {
         var stream = new MedianOfRunningArrayFloat();
         stream.insert(20.0f);
-        assertEquals(20.0f, stream.median());
+        assertEquals(20.0f, stream.getMedian());
         stream.insert(10.5f);
-        assertEquals(15.25f, stream.median());
+        assertEquals(15.25f, stream.getMedian());
         stream.insert(30.0f);
-        assertEquals(20.0f, stream.median());
+        assertEquals(20.0f, stream.getMedian());
     }
 
     @Test
     public void testWithByteValues() {
         var stream = new MedianOfRunningArrayByte();
         stream.insert((byte) 120);
-        assertEquals((byte) 120, stream.median());
+        assertEquals((byte) 120, stream.getMedian());
         stream.insert((byte) -120);
-        assertEquals((byte) 0, stream.median());
+        assertEquals((byte) 0, stream.getMedian());
         stream.insert((byte) 127);
-        assertEquals((byte) 120, stream.median());
+        assertEquals((byte) 120, stream.getMedian());
     }
 
     @Test
     public void testWithLongValues() {
         var stream = new MedianOfRunningArrayLong();
         stream.insert(120000000L);
-        assertEquals(120000000L, stream.median());
+        assertEquals(120000000L, stream.getMedian());
         stream.insert(92233720368547757L);
-        assertEquals(46116860244273878L, stream.median());
+        assertEquals(46116860244273878L, stream.getMedian());
     }
 
     @Test
     public void testWithDoubleValues() {
         var stream = new MedianOfRunningArrayDouble();
         stream.insert(12345.67891);
-        assertEquals(12345.67891, stream.median());
+        assertEquals(12345.67891, stream.getMedian());
         stream.insert(23456789.98);
-        assertEquals(11734567.83, stream.median(), .01);
+        assertEquals(11734567.83, stream.getMedian(), .01);
     }
 }

From fa2ca9db390e9549be6501bc22c2e4453185b16e Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Mon, 7 Jul 2025 23:29:52 +0200
Subject: [PATCH 0849/1338] refactor: improve PythagoreanTriple logic and add
 parameterized tests (#6350)

---
 .../maths/PythagoreanTriple.java              | 45 +++++++++++--------
 .../maths/PythagoreanTripleTest.java          | 24 +++++-----
 2 files changed, 39 insertions(+), 30 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java b/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java
index f535e9e6929b..2780b113d904 100644
--- a/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java
+++ b/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java
@@ -1,36 +1,43 @@
 package com.thealgorithms.maths;
 
 /**
- * https://en.wikipedia.org/wiki/Pythagorean_triple
+ * Utility class to check if three integers form a Pythagorean triple.
+ * A Pythagorean triple consists of three positive integers a, b, and c,
+ * such that a² + b² = c².
+ *
+ * Common examples:
+ * - (3, 4, 5)
+ * - (5, 12, 13)
+ *
+ * Reference: https://en.wikipedia.org/wiki/Pythagorean_triple
  */
 public final class PythagoreanTriple {
-    private PythagoreanTriple() {
-    }
 
-    public static void main(String[] args) {
-        assert isPythagTriple(3, 4, 5);
-        assert isPythagTriple(5, 12, 13);
-        assert isPythagTriple(6, 8, 10);
-        assert !isPythagTriple(10, 20, 30);
-        assert !isPythagTriple(6, 8, 100);
-        assert !isPythagTriple(-1, -1, 1);
+    private PythagoreanTriple() {
     }
 
     /**
-     * Check if a,b,c are a Pythagorean Triple
+     * Checks whether three integers form a Pythagorean triple.
+     * The order of parameters does not matter.
      *
-     * @param a x/y component length of a right triangle
-     * @param b y/x component length of a right triangle
-     * @param c hypotenuse length of a right triangle
-     * @return boolean <tt>true</tt> if a, b, c satisfy the Pythagorean theorem,
-     * otherwise
-     * <tt>false</tt>
+     * @param a one side length
+     * @param b another side length
+     * @param c another side length
+     * @return {@code true} if (a, b, c) can form a Pythagorean triple, otherwise {@code false}
      */
     public static boolean isPythagTriple(int a, int b, int c) {
         if (a <= 0 || b <= 0 || c <= 0) {
             return false;
-        } else {
-            return (a * a) + (b * b) == (c * c);
         }
+
+        // Sort the sides so the largest is treated as hypotenuse
+        int[] sides = {a, b, c};
+        java.util.Arrays.sort(sides);
+
+        int x = sides[0];
+        int y = sides[1];
+        int hypotenuse = sides[2];
+
+        return x * x + y * y == hypotenuse * hypotenuse;
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java b/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java
index 13ea58155dec..75219dc47b47 100644
--- a/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java
+++ b/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java
@@ -1,22 +1,24 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class PythagoreanTripleTest {
 
+    @ParameterizedTest
+    @CsvSource({"3, 4, 5, true", "6, 8, 10, true", "9, 12, 15, true", "12, 16, 20, true", "15, 20, 25, true", "18, 24, 30, true", "5, 20, 30, false", "6, 8, 100, false", "-2, -2, 2, false", "0, 0, 0, false", "5, 5, 5, false"})
+    void testIsPythagoreanTriple(int a, int b, int c, boolean expected) {
+        assertEquals(expected, PythagoreanTriple.isPythagTriple(a, b, c));
+    }
+
     @Test
-    public void testPythagoreanTriple() {
-        assertTrue(PythagoreanTriple.isPythagTriple(3, 4, 5));
-        assertTrue(PythagoreanTriple.isPythagTriple(6, 8, 10));
-        assertTrue(PythagoreanTriple.isPythagTriple(9, 12, 15));
-        assertTrue(PythagoreanTriple.isPythagTriple(12, 16, 20));
-        assertTrue(PythagoreanTriple.isPythagTriple(15, 20, 25));
-        assertTrue(PythagoreanTriple.isPythagTriple(18, 24, 30));
-        assertFalse(PythagoreanTriple.isPythagTriple(5, 20, 30));
-        assertFalse(PythagoreanTriple.isPythagTriple(6, 8, 100));
-        assertFalse(PythagoreanTriple.isPythagTriple(-2, -2, 2));
+    void testUnorderedInputStillValid() {
+        // Should still detect Pythagorean triples regardless of argument order
+        assertTrue(PythagoreanTriple.isPythagTriple(5, 3, 4));
+        assertTrue(PythagoreanTriple.isPythagTriple(13, 12, 5));
     }
 }

From 6c3049530f54b451e708ec78dafd31403447d840 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Tue, 8 Jul 2025 09:50:06 +0200
Subject: [PATCH 0850/1338] refactor: optimize ValidParentheses methods and add
 parameterized tests (#6352)

---
 .../strings/ValidParentheses.java             | 84 +++++++++----------
 .../strings/ValidParenthesesTest.java         | 26 ++----
 2 files changed, 46 insertions(+), 64 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/ValidParentheses.java b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
index 629fee495d84..25a72f379dec 100644
--- a/src/main/java/com/thealgorithms/strings/ValidParentheses.java
+++ b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
@@ -1,59 +1,53 @@
 package com.thealgorithms.strings;
-//        Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine
-//        if the input string is valid. An input string is valid if: Open brackets must be closed by
-//        the same type of brackets. Open brackets must be closed in the correct order. Every close
-//        bracket has a corresponding open bracket of the same type.
 
+import java.util.ArrayDeque;
+import java.util.Deque;
+import java.util.Map;
+
+/**
+ * Validates if a given string has valid matching parentheses.
+ * <p>
+ * A string is considered valid if:
+ * <ul>
+ *     <li>Open brackets are closed by the same type of brackets.</li>
+ *     <li>Brackets are closed in the correct order.</li>
+ *     <li>Every closing bracket has a corresponding open bracket of the same type.</li>
+ * </ul>
+ *
+ * Allowed characters: '(', ')', '{', '}', '[', ']'
+ */
 public final class ValidParentheses {
     private ValidParentheses() {
     }
+
+    private static final Map<Character, Character> BRACKET_PAIRS = Map.of(')', '(', '}', '{', ']', '[');
+
+    /**
+     * Checks if the input string has valid parentheses.
+     *
+     * @param s the string containing only bracket characters
+     * @return true if valid, false otherwise
+     * @throws IllegalArgumentException if the string contains invalid characters or is null
+     */
     public static boolean isValid(String s) {
-        char[] stack = new char[s.length()];
-        int head = 0;
+        if (s == null) {
+            throw new IllegalArgumentException("Input string cannot be null");
+        }
+
+        Deque<Character> stack = new ArrayDeque<>();
+
         for (char c : s.toCharArray()) {
-            switch (c) {
-            case '{':
-            case '[':
-            case '(':
-                stack[head++] = c;
-                break;
-            case '}':
-                if (head == 0 || stack[--head] != '{') {
-                    return false;
-                }
-                break;
-            case ')':
-                if (head == 0 || stack[--head] != '(') {
-                    return false;
-                }
-                break;
-            case ']':
-                if (head == 0 || stack[--head] != '[') {
+            if (BRACKET_PAIRS.containsValue(c)) {
+                stack.push(c); // opening bracket
+            } else if (BRACKET_PAIRS.containsKey(c)) {
+                if (stack.isEmpty() || stack.pop() != BRACKET_PAIRS.get(c)) {
                     return false;
                 }
-                break;
-            default:
-                throw new IllegalArgumentException("Unexpected character: " + c);
-            }
-        }
-        return head == 0;
-    }
-    public static boolean isValidParentheses(String s) {
-        int i = -1;
-        char[] stack = new char[s.length()];
-        String openBrackets = "({[";
-        String closeBrackets = ")}]";
-        for (char ch : s.toCharArray()) {
-            if (openBrackets.indexOf(ch) != -1) {
-                stack[++i] = ch;
             } else {
-                if (i >= 0 && openBrackets.indexOf(stack[i]) == closeBrackets.indexOf(ch)) {
-                    i--;
-                } else {
-                    return false;
-                }
+                throw new IllegalArgumentException("Unexpected character: " + c);
             }
         }
-        return i == -1;
+
+        return stack.isEmpty();
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
index 2b6884c91c8f..23d41b159fe2 100644
--- a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
+++ b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
@@ -1,27 +1,15 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class ValidParenthesesTest {
 
-    @Test
-    void testOne() {
-        assertTrue(ValidParentheses.isValid("()"));
-        assertTrue(ValidParentheses.isValidParentheses("()"));
-    }
-
-    @Test
-    void testTwo() {
-        assertTrue(ValidParentheses.isValid("()[]{}"));
-        assertTrue(ValidParentheses.isValidParentheses("()[]{}"));
-    }
-
-    @Test
-    void testThree() {
-        assertFalse(ValidParentheses.isValid("(]"));
-        assertFalse(ValidParentheses.isValidParentheses("(]"));
+    @ParameterizedTest(name = "Input: \"{0}\" → Expected: {1}")
+    @CsvSource({"'()', true", "'()[]{}', true", "'(]', false", "'{[]}', true", "'([{}])', true", "'([)]', false", "'', true", "'(', false", "')', false"})
+    void testIsValid(String input, boolean expected) {
+        assertEquals(expected, ValidParentheses.isValid(input));
     }
 }

From 476898723afc510d9248eebdff297080d7edaacb Mon Sep 17 00:00:00 2001
From: Andrii Siriak <siryaka@gmail.com>
Date: Tue, 8 Jul 2025 20:04:56 +0200
Subject: [PATCH 0851/1338] Update CODEOWNERS (#6353)

---
 .github/CODEOWNERS | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 8a0b18a54c0b..9a0617e18a06 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1 +1 @@
-* @DenizAltunkapan @yanglbme @vil02 @BamaCharanChhandogi @alxkm @siriak
+* @DenizAltunkapan @yanglbme @vil02 @alxkm

From c997a32018c6f876b6b4de96c765b1cc10ac1236 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Wed, 9 Jul 2025 21:36:39 +0300
Subject: [PATCH 0852/1338] refactor ShuffleArray: improve documentation and
 maintainability (#6357)

refactor ShuffleArray: Improve Documentation and Code Quality
---
 .../com/thealgorithms/misc/ShuffleArray.java  | 24 ++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/misc/ShuffleArray.java b/src/main/java/com/thealgorithms/misc/ShuffleArray.java
index 65d38adfc37a..e07c8df771d3 100644
--- a/src/main/java/com/thealgorithms/misc/ShuffleArray.java
+++ b/src/main/java/com/thealgorithms/misc/ShuffleArray.java
@@ -17,19 +17,37 @@
  * @author Rashi Dashore (https://github.com/rashi07dashore)
  */
 public final class ShuffleArray {
-    // Prevent instantiation
+
     private ShuffleArray() {
     }
 
     /**
-     * This method shuffles an array using the Fisher-Yates algorithm.
+     * Shuffles the provided array in-place using the Fisher–Yates algorithm.
      *
-     * @param arr is the input array to be shuffled
+     * @param arr the array to shuffle; must not be {@code null}
+     * @throws IllegalArgumentException if the input array is {@code null}
      */
     public static void shuffle(int[] arr) {
+        if (arr == null) {
+            throw new IllegalArgumentException("Input array must not be null");
+        }
+
         Random random = new Random();
         for (int i = arr.length - 1; i > 0; i--) {
             int j = random.nextInt(i + 1);
+            swap(arr, i, j);
+        }
+    }
+
+    /**
+     * Swaps two elements in an array.
+     *
+     * @param arr the array
+     * @param i   index of first element
+     * @param j   index of second element
+     */
+    private static void swap(int[] arr, int i, int j) {
+        if (i != j) {
             int temp = arr[i];
             arr[i] = arr[j];
             arr[j] = temp;

From a6aadd5b642a59ce366cec53325313b6bf853bf3 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Wed, 9 Jul 2025 21:49:58 +0300
Subject: [PATCH 0853/1338] refactor: improve Sparsity class with input
 validation and clearer logic (#6351)

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../java/com/thealgorithms/misc/Sparsity.java | 50 +++++++++++--------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/src/main/java/com/thealgorithms/misc/Sparsity.java b/src/main/java/com/thealgorithms/misc/Sparsity.java
index 08e50a121da4..4a919e0e55c6 100644
--- a/src/main/java/com/thealgorithms/misc/Sparsity.java
+++ b/src/main/java/com/thealgorithms/misc/Sparsity.java
@@ -1,40 +1,46 @@
 package com.thealgorithms.misc;
 
-/*
- *A matrix is sparse if many of its coefficients are zero (In general if 2/3rd of matrix elements
- *are 0, it is considered as sparse). The interest in sparsity arises because its exploitation can
- *lead to enormous computational savings and because many large matrix problems that occur in
- *practice are sparse.
+/**
+ * Utility class for calculating the sparsity of a matrix.
+ * A matrix is considered sparse if a large proportion of its elements are zero.
+ * Typically, if more than 2/3 of the elements are zero, the matrix is considered sparse.
  *
- * @author Ojasva Jain
+ * Sparsity is defined as:
+ * sparsity = (number of zero elements) / (total number of elements)
+ *
+ * This can lead to significant computational optimizations.
  */
+public final class Sparsity {
 
-final class Sparsity {
     private Sparsity() {
     }
 
-    /*
-     * @param mat the input matrix
-     * @return Sparsity of matrix
-     *
-     * where sparsity = number of zeroes/total elements in matrix
+    /**
+     * Calculates the sparsity of a given 2D matrix.
      *
+     * @param matrix the input matrix
+     * @return the sparsity value between 0 and 1
+     * @throws IllegalArgumentException if the matrix is null, empty, or contains empty rows
      */
-    static double sparsity(double[][] mat) {
-        if (mat == null || mat.length == 0) {
+    public static double sparsity(double[][] matrix) {
+        if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
             throw new IllegalArgumentException("Matrix cannot be null or empty");
         }
 
-        int zero = 0;
-        // Traversing the matrix to count number of zeroes
-        for (int i = 0; i < mat.length; i++) {
-            for (int j = 0; j < mat[i].length; j++) {
-                if (mat[i][j] == 0) {
-                    zero++;
+        int zeroCount = 0;
+        int totalElements = 0;
+
+        // Count the number of zero elements and total elements
+        for (double[] row : matrix) {
+            for (double value : row) {
+                if (value == 0.0) {
+                    zeroCount++;
                 }
+                totalElements++;
             }
         }
-        // return sparsity
-        return ((double) zero / (mat.length * mat[0].length));
+
+        // Return sparsity as a double
+        return (double) zeroCount / totalElements;
     }
 }

From 22cba2c84f510f40de922729528a1e886a084a80 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 10 Jul 2025 09:01:08 +0300
Subject: [PATCH 0854/1338] chore(deps): bump org.apache.commons:commons-lang3
 from 3.17.0 to 3.18.0 (#6364)

Bumps org.apache.commons:commons-lang3 from 3.17.0 to 3.18.0.

---
updated-dependencies:
- dependency-name: org.apache.commons:commons-lang3
  dependency-version: 3.18.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index ca2712d8c8ad..f5f1e0be12f7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -48,7 +48,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
-            <version>3.17.0</version>
+            <version>3.18.0</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>

From f3252793e196cfaaad932b3d86fb4f3e26da1406 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Thu, 10 Jul 2025 18:52:38 +0300
Subject: [PATCH 0855/1338] refactor: refactor Alphabetical and
 AlphabeticalTest (#6355)

---
 .../thealgorithms/strings/Alphabetical.java   | 28 ++++++++----------
 .../strings/AlphabeticalTest.java             | 29 +++++--------------
 2 files changed, 19 insertions(+), 38 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/Alphabetical.java b/src/main/java/com/thealgorithms/strings/Alphabetical.java
index de07dde2d510..ef2974eb427d 100644
--- a/src/main/java/com/thealgorithms/strings/Alphabetical.java
+++ b/src/main/java/com/thealgorithms/strings/Alphabetical.java
@@ -1,36 +1,32 @@
 package com.thealgorithms.strings;
 
 /**
+ * Utility class for checking if a string's characters are in alphabetical order.
+ * <p>
  * Alphabetical order is a system whereby character strings are placed in order
  * based on the position of the characters in the conventional ordering of an
- * alphabet. Wikipedia: https://en.wikipedia.org/wiki/Alphabetical_order
+ * alphabet.
+ * <p>
+ * Reference: <a href="https://en.wikipedia.org/wiki/Alphabetical_order">Wikipedia: Alphabetical Order</a>
  */
-final class Alphabetical {
+public final class Alphabetical {
     private Alphabetical() {
     }
 
-    public static void main(String[] args) {
-        assert !isAlphabetical("123abc");
-        assert isAlphabetical("aBC");
-        assert isAlphabetical("abc");
-        assert !isAlphabetical("xyzabc");
-        assert isAlphabetical("abcxyz");
-    }
-
     /**
-     * Check if a string is alphabetical order or not
+     * Checks whether the characters in the given string are in alphabetical order.
+     * Non-letter characters will cause the check to fail.
      *
-     * @param s a string
-     * @return {@code true} if given string is alphabetical order, otherwise
-     * {@code false}
+     * @param s the input string
+     * @return {@code true} if all characters are in alphabetical order (case-insensitive), otherwise {@code false}
      */
     public static boolean isAlphabetical(String s) {
         s = s.toLowerCase();
         for (int i = 0; i < s.length() - 1; ++i) {
-            if (!Character.isLetter(s.charAt(i)) || !(s.charAt(i) <= s.charAt(i + 1))) {
+            if (!Character.isLetter(s.charAt(i)) || s.charAt(i) > s.charAt(i + 1)) {
                 return false;
             }
         }
-        return true;
+        return !s.isEmpty() && Character.isLetter(s.charAt(s.length() - 1));
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java b/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java
index 083239152ec2..7b41e11ef22f 100644
--- a/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java
+++ b/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java
@@ -1,30 +1,15 @@
 package com.thealgorithms.strings;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class AlphabeticalTest {
 
-    @Test
-    public void isAlphabetical() {
-        // expected to be true
-        String input1 = "abcdefghijklmno";
-        String input2 = "abcdxxxyzzzz";
-        String input3 = "fpw";
-
-        // expected to be false
-        String input4 = "123a";
-        String input5 = "abcABC";
-        String input6 = "abcdefghikjlmno";
-
-        assertTrue(Alphabetical.isAlphabetical(input1));
-        assertTrue(Alphabetical.isAlphabetical(input2));
-        assertTrue(Alphabetical.isAlphabetical(input3));
-
-        assertFalse(Alphabetical.isAlphabetical(input4));
-        assertFalse(Alphabetical.isAlphabetical(input5));
-        assertFalse(Alphabetical.isAlphabetical(input6));
+    @ParameterizedTest(name = "\"{0}\" → Expected: {1}")
+    @CsvSource({"'abcdefghijklmno', true", "'abcdxxxyzzzz', true", "'123a', false", "'abcABC', false", "'abcdefghikjlmno', false", "'aBC', true", "'abc', true", "'xyzabc', false", "'abcxyz', true", "'', false", "'1', false"})
+    void testIsAlphabetical(String input, boolean expected) {
+        assertEquals(expected, Alphabetical.isAlphabetical(input));
     }
 }

From 2ccc15671f68e8d9299c5f90067359174f76f6a1 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Fri, 11 Jul 2025 22:32:42 +0300
Subject: [PATCH 0856/1338] refactor: clean up LargestRectangle and convert
 tests to parameterized format (#6356)

* refactor: clean up LargestRectangle and convert tests to parameterized format

* refactor: fix clang formatting issue

* refactor: fix clang formatting issue for test data

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../stacks/LargestRectangle.java              | 50 +++++++-----
 .../stacks/LargestRectangleTest.java          | 79 ++++---------------
 2 files changed, 47 insertions(+), 82 deletions(-)

diff --git a/src/main/java/com/thealgorithms/stacks/LargestRectangle.java b/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
index 006e03632e63..eb222c8c488e 100644
--- a/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
+++ b/src/main/java/com/thealgorithms/stacks/LargestRectangle.java
@@ -3,36 +3,50 @@
 import java.util.Stack;
 
 /**
+ * Utility class to calculate the largest rectangle area in a histogram.
+ * Each bar's width is assumed to be 1 unit.
  *
- * @author mohd rameez github.com/rameez471
+ * <p>This implementation uses a monotonic stack to efficiently calculate
+ * the area of the largest rectangle that can be formed from the histogram bars.</p>
+ *
+ * <p>Example usage:
+ * <pre>{@code
+ *     int[] heights = {2, 1, 5, 6, 2, 3};
+ *     String area = LargestRectangle.largestRectangleHistogram(heights);
+ *     // area is "10"
+ * }</pre>
  */
-
 public final class LargestRectangle {
+
     private LargestRectangle() {
     }
 
+    /**
+     * Calculates the largest rectangle area in the given histogram.
+     *
+     * @param heights an array of non-negative integers representing bar heights
+     * @return the largest rectangle area as a {@link String}
+     */
     public static String largestRectangleHistogram(int[] heights) {
-        int n = heights.length;
         int maxArea = 0;
-        Stack<int[]> st = new Stack<>();
-        for (int i = 0; i < n; i++) {
+        Stack<int[]> stack = new Stack<>();
+
+        for (int i = 0; i < heights.length; i++) {
             int start = i;
-            while (!st.isEmpty() && st.peek()[1] > heights[i]) {
-                int[] tmp = st.pop();
-                maxArea = Math.max(maxArea, tmp[1] * (i - tmp[0]));
-                start = tmp[0];
+            while (!stack.isEmpty() && stack.peek()[1] > heights[i]) {
+                int[] popped = stack.pop();
+                maxArea = Math.max(maxArea, popped[1] * (i - popped[0]));
+                start = popped[0];
             }
-            st.push(new int[] {start, heights[i]});
+            stack.push(new int[] {start, heights[i]});
         }
-        while (!st.isEmpty()) {
-            int[] tmp = st.pop();
-            maxArea = Math.max(maxArea, tmp[1] * (n - tmp[0]));
+
+        int totalLength = heights.length;
+        while (!stack.isEmpty()) {
+            int[] remaining = stack.pop();
+            maxArea = Math.max(maxArea, remaining[1] * (totalLength - remaining[0]));
         }
-        return Integer.toString(maxArea);
-    }
 
-    public static void main(String[] args) {
-        assert largestRectangleHistogram(new int[] {2, 1, 5, 6, 2, 3}).equals("10");
-        assert largestRectangleHistogram(new int[] {2, 4}).equals("4");
+        return Integer.toString(maxArea);
     }
 }
diff --git a/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java b/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java
index a54372adda0e..fec5d371c106 100644
--- a/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java
+++ b/src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java
@@ -2,76 +2,27 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class LargestRectangleTest {
 
-    @Test
-    void testLargestRectangleHistogramWithTypicalCases() {
-        // Typical case with mixed heights
-        int[] heights = {2, 1, 5, 6, 2, 3};
-        String expected = "10";
-        String result = LargestRectangle.largestRectangleHistogram(heights);
-        assertEquals(expected, result);
-
-        // Another typical case with increasing heights
-        heights = new int[] {2, 4};
-        expected = "4";
-        result = LargestRectangle.largestRectangleHistogram(heights);
-        assertEquals(expected, result);
-
-        // Case with multiple bars of the same height
-        heights = new int[] {4, 4, 4, 4};
-        expected = "16";
-        result = LargestRectangle.largestRectangleHistogram(heights);
-        assertEquals(expected, result);
+    @ParameterizedTest(name = "Histogram: {0} → Expected area: {1}")
+    @MethodSource("histogramProvider")
+    void testLargestRectangleHistogram(int[] heights, String expected) {
+        assertEquals(expected, LargestRectangle.largestRectangleHistogram(heights));
     }
 
-    @Test
-    void testLargestRectangleHistogramWithEdgeCases() {
-        // Edge case with an empty array
-        int[] heights = {};
-        String expected = "0";
-        String result = LargestRectangle.largestRectangleHistogram(heights);
-        assertEquals(expected, result);
-
-        // Edge case with a single bar
-        heights = new int[] {5};
-        expected = "5";
-        result = LargestRectangle.largestRectangleHistogram(heights);
-        assertEquals(expected, result);
-
-        // Edge case with all bars of height 0
-        heights = new int[] {0, 0, 0};
-        expected = "0";
-        result = LargestRectangle.largestRectangleHistogram(heights);
-        assertEquals(expected, result);
+    static Stream<Arguments> histogramProvider() {
+        return Stream.of(Arguments.of(new int[] {2, 1, 5, 6, 2, 3}, "10"), Arguments.of(new int[] {2, 4}, "4"), Arguments.of(new int[] {4, 4, 4, 4}, "16"), Arguments.of(new int[] {}, "0"), Arguments.of(new int[] {5}, "5"), Arguments.of(new int[] {0, 0, 0}, "0"),
+            Arguments.of(new int[] {6, 2, 5, 4, 5, 1, 6}, "12"), Arguments.of(new int[] {2, 1, 5, 6, 2, 3, 1}, "10"), Arguments.of(createLargeArray(10000, 1), "10000"));
     }
 
-    @Test
-    void testLargestRectangleHistogramWithLargeInput() {
-        // Large input case
-        int[] heights = new int[10000];
-        for (int i = 0; i < heights.length; i++) {
-            heights[i] = 1;
-        }
-        String expected = "10000";
-        String result = LargestRectangle.largestRectangleHistogram(heights);
-        assertEquals(expected, result);
-    }
-
-    @Test
-    void testLargestRectangleHistogramWithComplexCases() {
-        // Complex case with a mix of heights
-        int[] heights = {6, 2, 5, 4, 5, 1, 6};
-        String expected = "12";
-        String result = LargestRectangle.largestRectangleHistogram(heights);
-        assertEquals(expected, result);
-
-        // Case with a peak in the middle
-        heights = new int[] {2, 1, 5, 6, 2, 3, 1};
-        expected = "10";
-        result = LargestRectangle.largestRectangleHistogram(heights);
-        assertEquals(expected, result);
+    private static int[] createLargeArray(int size, int value) {
+        int[] arr = new int[size];
+        java.util.Arrays.fill(arr, value);
+        return arr;
     }
 }

From 3e0fd11a96e80baaa51a47b4ea4f45edeee261c0 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Fri, 11 Jul 2025 22:36:29 +0300
Subject: [PATCH 0857/1338] refactor: refactoring and documenting `Isomorphic
 String Checker` (#6359)

refactor: refactoring and documenting Isomorphic String Checker

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../com/thealgorithms/strings/Isomorphic.java | 43 +++++++++++++------
 .../thealgorithms/strings/IsomorphicTest.java |  4 +-
 2 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/Isomorphic.java b/src/main/java/com/thealgorithms/strings/Isomorphic.java
index ccd686170715..7ee00e62e16b 100644
--- a/src/main/java/com/thealgorithms/strings/Isomorphic.java
+++ b/src/main/java/com/thealgorithms/strings/Isomorphic.java
@@ -5,35 +5,54 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Utility class to check if two strings are isomorphic.
+ *
+ * <p>
+ * Two strings {@code s} and {@code t} are isomorphic if the characters in {@code s}
+ * can be replaced to get {@code t}, while preserving the order of characters.
+ * Each character must map to exactly one character, and no two characters can map to the same character.
+ * </p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Isomorphism_(computer_science)">Isomorphic Strings</a>
+ */
 public final class Isomorphic {
+
     private Isomorphic() {
     }
 
-    public static boolean checkStrings(String s, String t) {
+    /**
+     * Checks if two strings are isomorphic.
+     *
+     * @param s the first input string
+     * @param t the second input string
+     * @return {@code true} if {@code s} and {@code t} are isomorphic; {@code false} otherwise
+     */
+    public static boolean areIsomorphic(String s, String t) {
         if (s.length() != t.length()) {
             return false;
         }
 
-        // To mark the characters of string using MAP
-        // character of first string as KEY and another as VALUE
-        // now check occurence by keeping the track with SET data structure
-        Map<Character, Character> characterMap = new HashMap<>();
-        Set<Character> trackUniqueCharacter = new HashSet<>();
+        Map<Character, Character> map = new HashMap<>();
+        Set<Character> usedCharacters = new HashSet<>();
 
         for (int i = 0; i < s.length(); i++) {
-            if (characterMap.containsKey(s.charAt(i))) {
-                if (t.charAt(i) != characterMap.get(s.charAt(i))) {
+            char sourceChar = s.charAt(i);
+            char targetChar = t.charAt(i);
+
+            if (map.containsKey(sourceChar)) {
+                if (map.get(sourceChar) != targetChar) {
                     return false;
                 }
             } else {
-                if (trackUniqueCharacter.contains(t.charAt(i))) {
+                if (usedCharacters.contains(targetChar)) {
                     return false;
                 }
-
-                characterMap.put(s.charAt(i), t.charAt(i));
+                map.put(sourceChar, targetChar);
+                usedCharacters.add(targetChar);
             }
-            trackUniqueCharacter.add(t.charAt(i));
         }
+
         return true;
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/IsomorphicTest.java b/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
index 4dd13fbc34ee..5c3ed89b65d3 100644
--- a/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
+++ b/src/test/java/com/thealgorithms/strings/IsomorphicTest.java
@@ -12,8 +12,8 @@ public final class IsomorphicTest {
     @ParameterizedTest
     @MethodSource("inputs")
     public void testCheckStrings(String str1, String str2, Boolean expected) {
-        assertEquals(expected, Isomorphic.checkStrings(str1, str2));
-        assertEquals(expected, Isomorphic.checkStrings(str2, str1));
+        assertEquals(expected, Isomorphic.areIsomorphic(str1, str2));
+        assertEquals(expected, Isomorphic.areIsomorphic(str2, str1));
     }
 
     private static Stream<Arguments> inputs() {

From 048bba9499f9844d30a0411d8b5552cae2cfcab8 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Fri, 11 Jul 2025 22:39:33 +0300
Subject: [PATCH 0858/1338] refactor: adding docs for `LongestCommonPrefixTest`
 and Parameterized Tests (#6360)

* refactor: adding docs for LongestCommonPrefixTest and Parameterized Tests

* checkstyle: fix clang formatting

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../strings/LongestCommonPrefix.java          | 30 ++++++--
 .../strings/LongestCommonPrefixTest.java      | 75 ++++---------------
 2 files changed, 38 insertions(+), 67 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java b/src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java
index 0fabdaa2658b..3348b9cf860c 100644
--- a/src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java
+++ b/src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java
@@ -2,21 +2,41 @@
 
 import java.util.Arrays;
 
+/**
+ * Utility class for string operations.
+ * <p>
+ * This class provides a method to find the longest common prefix (LCP)
+ * among an array of strings.
+ * </p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Longest_common_prefix">Longest Common Prefix - Wikipedia</a>
+ */
 public final class LongestCommonPrefix {
-    public String longestCommonPrefix(String[] strs) {
+
+    private LongestCommonPrefix() {
+    }
+
+    /**
+     * Finds the longest common prefix among a list of strings using lexicographical sorting.
+     * The prefix is common to the first and last elements after sorting the array.
+     *
+     * @param strs array of input strings
+     * @return the longest common prefix, or empty string if none exists
+     */
+    public static String longestCommonPrefix(String[] strs) {
         if (strs == null || strs.length == 0) {
             return "";
         }
 
         Arrays.sort(strs);
-        String shortest = strs[0];
-        String longest = strs[strs.length - 1];
+        String first = strs[0];
+        String last = strs[strs.length - 1];
 
         int index = 0;
-        while (index < shortest.length() && index < longest.length() && shortest.charAt(index) == longest.charAt(index)) {
+        while (index < first.length() && index < last.length() && first.charAt(index) == last.charAt(index)) {
             index++;
         }
 
-        return shortest.substring(0, index);
+        return first.substring(0, index);
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java b/src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java
index 580a2726d285..84e54f75e8cb 100644
--- a/src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java
+++ b/src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java
@@ -2,72 +2,23 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class LongestCommonPrefixTest {
 
-    private final LongestCommonPrefix longestCommonPrefix = new LongestCommonPrefix();
-
-    @Test
-    public void testCommonPrefix() {
-        String[] input = {"flower", "flow", "flight"};
-        String expected = "fl";
-        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
-    }
-
-    @Test
-    public void testNoCommonPrefix() {
-        String[] input = {"dog", "racecar", "car"};
-        String expected = "";
-        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
-    }
-
-    @Test
-    public void testEmptyArray() {
-        String[] input = {};
-        String expected = "";
-        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
-    }
-
-    @Test
-    public void testNullArray() {
-        String[] input = null;
-        String expected = "";
-        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
-    }
-
-    @Test
-    public void testSingleString() {
-        String[] input = {"single"};
-        String expected = "single";
-        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
-    }
-
-    @Test
-    public void testCommonPrefixWithDifferentLengths() {
-        String[] input = {"ab", "a"};
-        String expected = "a";
-        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
-    }
-
-    @Test
-    public void testAllSameStrings() {
-        String[] input = {"test", "test", "test"};
-        String expected = "test";
-        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
-    }
-
-    @Test
-    public void testPrefixAtEnd() {
-        String[] input = {"abcde", "abcfgh", "abcmnop"};
-        String expected = "abc";
-        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    @ParameterizedTest(name = "{index} => input={0}, expected=\"{1}\"")
+    @MethodSource("provideTestCases")
+    @DisplayName("Test Longest Common Prefix")
+    void testLongestCommonPrefix(String[] input, String expected) {
+        assertEquals(expected, LongestCommonPrefix.longestCommonPrefix(input));
     }
 
-    @Test
-    public void testMixedCase() {
-        String[] input = {"Flower", "flow", "flight"};
-        String expected = "";
-        assertEquals(expected, longestCommonPrefix.longestCommonPrefix(input));
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new String[] {"flower", "flow", "flight"}, "fl"), Arguments.of(new String[] {"dog", "racecar", "car"}, ""), Arguments.of(new String[] {}, ""), Arguments.of(null, ""), Arguments.of(new String[] {"single"}, "single"), Arguments.of(new String[] {"ab", "a"}, "a"),
+            Arguments.of(new String[] {"test", "test", "test"}, "test"), Arguments.of(new String[] {"abcde", "abcfgh", "abcmnop"}, "abc"), Arguments.of(new String[] {"Flower", "flow", "flight"}, ""));
     }
 }

From 0a4f5542d932037dbbd071117477c2cbdec6bb41 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Fri, 11 Jul 2025 22:42:45 +0300
Subject: [PATCH 0859/1338] cleanup: Improve docs, safety, and readability in
 `RangeInSortedArray` (#6361)

* cleanup: Improve docs, safety, and readability in RangeInSortedArray

* formatting: fix comment formatting issue

* formatting: fix array formatting issue

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../misc/RangeInSortedArray.java              | 78 +++++++++++++++----
 1 file changed, 61 insertions(+), 17 deletions(-)

diff --git a/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java b/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
index 6d3caa1814b6..0ae73dd73f09 100644
--- a/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
+++ b/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java
@@ -1,25 +1,46 @@
 package com.thealgorithms.misc;
 
+/**
+ * Utility class for operations to find the range of occurrences of a key
+ * in a sorted (non-decreasing) array, and to count elements less than or equal to a given key.
+ */
 public final class RangeInSortedArray {
+
     private RangeInSortedArray() {
     }
 
-    // Get the 1st and last occurrence index of a number 'key' in a non-decreasing array 'nums'
-    // Gives [-1, -1] in case element doesn't exist in array
+    /**
+     * Finds the first and last occurrence indices of the key in a sorted array.
+     *
+     * @param nums sorted array of integers (non-decreasing order)
+     * @param key the target value to search for
+     * @return int array of size two where
+     *         - index 0 is the first occurrence of key,
+     *         - index 1 is the last occurrence of key,
+     *         or [-1, -1] if the key does not exist in the array.
+     */
     public static int[] sortedRange(int[] nums, int key) {
         int[] range = new int[] {-1, -1};
-        alteredBinSearchIter(nums, key, 0, nums.length - 1, range, true);
-        alteredBinSearchIter(nums, key, 0, nums.length - 1, range, false);
+        alteredBinSearchIter(nums, key, 0, nums.length - 1, range, true); // find left boundary
+        alteredBinSearchIter(nums, key, 0, nums.length - 1, range, false); // find right boundary
         return range;
     }
 
-    // Recursive altered binary search which searches for leftmost as well as rightmost occurrence
-    // of 'key'
+    /**
+     * Recursive altered binary search to find either the leftmost or rightmost occurrence of a key.
+     *
+     * @param nums the sorted array
+     * @param key the target to find
+     * @param left current left bound in search
+     * @param right current right bound in search
+     * @param range array to update with boundaries: range[0] for leftmost, range[1] for rightmost
+     * @param goLeft if true, searches for leftmost occurrence; if false, for rightmost occurrence
+     */
     public static void alteredBinSearch(int[] nums, int key, int left, int right, int[] range, boolean goLeft) {
         if (left > right) {
             return;
         }
-        int mid = (left + right) >>> 1;
+        int mid = left + ((right - left) >>> 1);
         if (nums[mid] > key) {
             alteredBinSearch(nums, key, left, mid - 1, range, goLeft);
         } else if (nums[mid] < key) {
@@ -41,11 +62,19 @@ public static void alteredBinSearch(int[] nums, int key, int left, int right, in
         }
     }
 
-    // Iterative altered binary search which searches for leftmost as well as rightmost occurrence
-    // of 'key'
+    /**
+     * Iterative altered binary search to find either the leftmost or rightmost occurrence of a key.
+     *
+     * @param nums the sorted array
+     * @param key the target to find
+     * @param left initial left bound
+     * @param right initial right bound
+     * @param range array to update with boundaries: range[0] for leftmost, range[1] for rightmost
+     * @param goLeft if true, searches for leftmost occurrence; if false, for rightmost occurrence
+     */
     public static void alteredBinSearchIter(int[] nums, int key, int left, int right, int[] range, boolean goLeft) {
         while (left <= right) {
-            final int mid = (left + right) >>> 1;
+            int mid = left + ((right - left) >>> 1);
             if (nums[mid] > key) {
                 right = mid - 1;
             } else if (nums[mid] < key) {
@@ -55,33 +84,48 @@ public static void alteredBinSearchIter(int[] nums, int key, int left, int right
                     if (mid == 0 || nums[mid - 1] != key) {
                         range[0] = mid;
                         return;
-                    } else {
-                        right = mid - 1;
                     }
+                    right = mid - 1;
                 } else {
                     if (mid == nums.length - 1 || nums[mid + 1] != key) {
                         range[1] = mid;
                         return;
-                    } else {
-                        left = mid + 1;
                     }
+                    left = mid + 1;
                 }
             }
         }
     }
 
+    /**
+     * Counts the number of elements strictly less than the given key.
+     *
+     * @param nums sorted array
+     * @param key the key to compare
+     * @return the count of elements less than the key
+     */
     public static int getCountLessThan(int[] nums, int key) {
         return getLessThan(nums, key, 0, nums.length - 1);
     }
 
+    /**
+     * Helper method using binary search to count elements less than or equal to the key.
+     *
+     * @param nums sorted array
+     * @param key the key to compare
+     * @param left current left bound
+     * @param right current right bound
+     * @return count of elements less than or equal to the key
+     */
     public static int getLessThan(int[] nums, int key, int left, int right) {
         int count = 0;
         while (left <= right) {
-            final int mid = (left + right) >>> 1;
+            int mid = left + ((right - left) >>> 1);
             if (nums[mid] > key) {
                 right = mid - 1;
-            } else if (nums[mid] <= key) {
-                count = mid + 1; // At least mid+1 elements exist which are <= key
+            } else {
+                // nums[mid] <= key
+                count = mid + 1; // all elements from 0 to mid inclusive are <= key
                 left = mid + 1;
             }
         }

From acb4753d65ce960222bf37ba3ae38cbb59cd8ed5 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sat, 12 Jul 2025 09:44:57 +0300
Subject: [PATCH 0860/1338] refactor: Improve readability and code clarity in
 `InfixToPostfix` (#6362)

refactor: improve InfixToPostfix

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../thealgorithms/stacks/InfixToPostfix.java  | 100 +++++++++++++-----
 .../stacks/InfixToPostfixTest.java            |   4 +-
 2 files changed, 73 insertions(+), 31 deletions(-)

diff --git a/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java b/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java
index 33611bd73dba..77ca3e70849f 100644
--- a/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java
+++ b/src/main/java/com/thealgorithms/stacks/InfixToPostfix.java
@@ -4,54 +4,96 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+/**
+ * Utility class for converting an infix arithmetic expression
+ * into its equivalent postfix (Reverse Polish Notation) form.
+ * <p>
+ * This class provides a static method to perform the conversion,
+ * validating balanced brackets before processing.
+ * </p>
+ */
 public final class InfixToPostfix {
+
     private InfixToPostfix() {
     }
 
-    public static String infix2PostFix(String infixExpression) throws Exception {
+    /**
+     * Converts a given infix expression string to a postfix expression string.
+     * <p>
+     * The method first checks if the brackets in the input expression are balanced
+     * by calling {@code BalancedBrackets.isBalanced} on the filtered brackets.
+     * If the brackets are not balanced, it throws an IllegalArgumentException.
+     * </p>
+     * <p>
+     * Supported operators are: {@code +, -, *, /, ^}
+     * and operands can be letters or digits.
+     * </p>
+     *
+     * @param infixExpression the arithmetic expression in infix notation
+     * @return the equivalent postfix notation expression
+     * @throws IllegalArgumentException if the brackets in the expression are unbalanced
+     */
+    public static String infix2PostFix(String infixExpression) {
         if (!BalancedBrackets.isBalanced(filterBrackets(infixExpression))) {
-            throw new Exception("invalid expression");
+            throw new IllegalArgumentException("Invalid expression: unbalanced brackets.");
         }
+
         StringBuilder output = new StringBuilder();
-        Stack<Character> stack = new Stack<>();
-        for (char element : infixExpression.toCharArray()) {
-            if (Character.isLetterOrDigit(element)) {
-                output.append(element);
-            } else if (element == '(') {
-                stack.push(element);
-            } else if (element == ')') {
-                while (!stack.isEmpty() && stack.peek() != '(') {
-                    output.append(stack.pop());
+        Stack<Character> operatorStack = new Stack<>();
+
+        for (char token : infixExpression.toCharArray()) {
+            if (Character.isLetterOrDigit(token)) {
+                // Append operands (letters or digits) directly to output
+                output.append(token);
+            } else if (token == '(') {
+                // Push '(' to stack
+                operatorStack.push(token);
+            } else if (token == ')') {
+                // Pop and append until '(' is found
+                while (!operatorStack.isEmpty() && operatorStack.peek() != '(') {
+                    output.append(operatorStack.pop());
                 }
-                stack.pop();
+                operatorStack.pop(); // Remove '(' from stack
             } else {
-                while (!stack.isEmpty() && precedence(element) <= precedence(stack.peek())) {
-                    output.append(stack.pop());
+                // Pop operators with higher or equal precedence and append them
+                while (!operatorStack.isEmpty() && precedence(token) <= precedence(operatorStack.peek())) {
+                    output.append(operatorStack.pop());
                 }
-                stack.push(element);
+                operatorStack.push(token);
             }
         }
-        while (!stack.isEmpty()) {
-            output.append(stack.pop());
+
+        // Pop any remaining operators
+        while (!operatorStack.isEmpty()) {
+            output.append(operatorStack.pop());
         }
+
         return output.toString();
     }
 
+    /**
+     * Returns the precedence level of the given operator.
+     *
+     * @param operator the operator character (e.g., '+', '-', '*', '/', '^')
+     * @return the precedence value: higher means higher precedence,
+     *         or -1 if the character is not a recognized operator
+     */
     private static int precedence(char operator) {
-        switch (operator) {
-        case '+':
-        case '-':
-            return 0;
-        case '*':
-        case '/':
-            return 1;
-        case '^':
-            return 2;
-        default:
-            return -1;
-        }
+        return switch (operator) {
+            case '+', '-' -> 0;
+            case '*', '/' -> 1;
+            case '^' -> 2;
+            default -> -1;
+        };
     }
 
+    /**
+     * Extracts only the bracket characters from the input string.
+     * Supports parentheses (), curly braces {}, square brackets [], and angle brackets &lt;&gt;.
+     *
+     * @param input the original expression string
+     * @return a string containing only bracket characters from the input
+     */
     private static String filterBrackets(String input) {
         Pattern pattern = Pattern.compile("[^(){}\\[\\]<>]");
         Matcher matcher = pattern.matcher(input);
diff --git a/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java b/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java
index 02a08e393a00..bd63c1ac28f2 100644
--- a/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java
+++ b/src/test/java/com/thealgorithms/stacks/InfixToPostfixTest.java
@@ -12,7 +12,7 @@ class InfixToPostfixTest {
 
     @ParameterizedTest
     @MethodSource("provideValidExpressions")
-    void testValidExpressions(String infix, String expectedPostfix) throws Exception {
+    void testValidExpressions(String infix, String expectedPostfix) {
         assertEquals(expectedPostfix, InfixToPostfix.infix2PostFix(infix));
     }
 
@@ -28,6 +28,6 @@ void testInvalidExpressions(String infix, String expectedMessage) {
     }
 
     private static Stream<Arguments> provideInvalidExpressions() {
-        return Stream.of(Arguments.of("((a+b)*c-d", "invalid expression"));
+        return Stream.of(Arguments.of("((a+b)*c-d", "Invalid expression: unbalanced brackets."));
     }
 }

From 7590d8234f236729bafe4e5c826fb3eaff5d6444 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sat, 12 Jul 2025 09:47:49 +0300
Subject: [PATCH 0861/1338] refactor: add JavaDocs and improve readability in
 `InfixToPrefix` (#6363)

* refactor: add JavaDocs and improve readability in InfixToPrefix

* formatting: remove redundant newline

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../thealgorithms/stacks/InfixToPrefix.java   | 106 +++++++++++-------
 .../stacks/InfixToPrefixTest.java             |   2 +-
 2 files changed, 66 insertions(+), 42 deletions(-)

diff --git a/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java b/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java
index 3d90d14e0d1e..e9ee5e208df6 100644
--- a/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java
+++ b/src/main/java/com/thealgorithms/stacks/InfixToPrefix.java
@@ -4,85 +4,109 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+/**
+ * Utility class for converting an infix arithmetic expression
+ * into its equivalent prefix notation expression.
+ * <p>
+ * This class provides a static method to perform the conversion,
+ * validating balanced brackets before processing.
+ * </p>
+ */
 public final class InfixToPrefix {
+
     private InfixToPrefix() {
     }
 
     /**
-     * Convert an infix expression to a prefix expression using stack.
+     * Converts a given infix expression string to a prefix expression string.
+     * <p>
+     * The method validates that the input expression has balanced brackets using
+     * {@code BalancedBrackets.isBalanced} on the filtered bracket characters.
+     * It throws an {@code IllegalArgumentException} if the brackets are unbalanced,
+     * and a {@code NullPointerException} if the input is null.
+     * </p>
+     * <p>
+     * Supported operators: {@code +, -, *, /, ^} and operands can be letters or digits.
+     * </p>
      *
-     * @param infixExpression the infix expression to convert
-     * @return the prefix expression
-     * @throws IllegalArgumentException if the infix expression has unbalanced brackets
-     * @throws NullPointerException     if the infix expression is null
+     * @param infixExpression the arithmetic expression in infix notation
+     * @return the equivalent prefix notation expression
+     * @throws IllegalArgumentException if brackets are unbalanced
+     * @throws NullPointerException     if the input expression is null
      */
-    public static String infix2Prefix(String infixExpression) throws IllegalArgumentException {
+    public static String infix2Prefix(String infixExpression) {
         if (infixExpression == null) {
             throw new NullPointerException("Input expression cannot be null.");
         }
+
         infixExpression = infixExpression.trim();
         if (infixExpression.isEmpty()) {
             return "";
         }
+
         if (!BalancedBrackets.isBalanced(filterBrackets(infixExpression))) {
             throw new IllegalArgumentException("Invalid expression: unbalanced brackets.");
         }
 
         StringBuilder output = new StringBuilder();
-        Stack<Character> stack = new Stack<>();
-        // Reverse the infix expression for prefix conversion
+        Stack<Character> operatorStack = new Stack<>();
+
+        // Reverse the infix expression to facilitate prefix conversion
         String reversedInfix = new StringBuilder(infixExpression).reverse().toString();
-        for (char element : reversedInfix.toCharArray()) {
-            if (Character.isLetterOrDigit(element)) {
-                output.append(element);
-            } else if (element == ')') {
-                stack.push(element);
-            } else if (element == '(') {
-                while (!stack.isEmpty() && stack.peek() != ')') {
-                    output.append(stack.pop());
+
+        for (char token : reversedInfix.toCharArray()) {
+            if (Character.isLetterOrDigit(token)) {
+                // Append operands directly to output
+                output.append(token);
+            } else if (token == ')') {
+                // Push ')' onto stack (since expression is reversed, '(' and ')' roles swapped)
+                operatorStack.push(token);
+            } else if (token == '(') {
+                // Pop operators until ')' is found
+                while (!operatorStack.isEmpty() && operatorStack.peek() != ')') {
+                    output.append(operatorStack.pop());
                 }
-                stack.pop();
+                operatorStack.pop(); // Remove the ')'
             } else {
-                while (!stack.isEmpty() && precedence(element) < precedence(stack.peek())) {
-                    output.append(stack.pop());
+                // Pop operators with higher precedence before pushing current operator
+                while (!operatorStack.isEmpty() && precedence(token) < precedence(operatorStack.peek())) {
+                    output.append(operatorStack.pop());
                 }
-                stack.push(element);
+                operatorStack.push(token);
             }
         }
-        while (!stack.isEmpty()) {
-            output.append(stack.pop());
+
+        // Append any remaining operators in stack
+        while (!operatorStack.isEmpty()) {
+            output.append(operatorStack.pop());
         }
 
-        // Reverse the result to get the prefix expression
+        // Reverse the output to obtain the final prefix expression
         return output.reverse().toString();
     }
 
     /**
-     * Determines the precedence of an operator.
+     * Returns the precedence level of the given operator.
      *
-     * @param operator the operator whose precedence is to be determined
-     * @return the precedence of the operator
+     * @param operator the operator character (e.g., '+', '-', '*', '/', '^')
+     * @return the precedence value: higher means higher precedence,
+     *         or -1 if the character is not a recognized operator
      */
     private static int precedence(char operator) {
-        switch (operator) {
-        case '+':
-        case '-':
-            return 0;
-        case '*':
-        case '/':
-            return 1;
-        case '^':
-            return 2;
-        default:
-            return -1;
-        }
+        return switch (operator) {
+            case '+', '-' -> 0;
+            case '*', '/' -> 1;
+            case '^' -> 2;
+            default -> -1;
+        };
     }
 
     /**
-     * Filters out all characters from the input string except brackets.
+     * Extracts only the bracket characters from the input string.
+     * Supports parentheses (), curly braces {}, square brackets [], and angle brackets &lt;&gt;.
      *
-     * @param input the input string to filter
-     * @return a string containing only brackets from the input string
+     * @param input the original expression string
+     * @return a string containing only bracket characters from the input
      */
     private static String filterBrackets(String input) {
         Pattern pattern = Pattern.compile("[^(){}\\[\\]<>]");
diff --git a/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java b/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java
index 91be8a63da62..0ea948307336 100644
--- a/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java
+++ b/src/test/java/com/thealgorithms/stacks/InfixToPrefixTest.java
@@ -13,7 +13,7 @@ public class InfixToPrefixTest {
 
     @ParameterizedTest
     @MethodSource("provideValidExpressions")
-    void testValidExpressions(String infix, String expectedPrefix) throws Exception {
+    void testValidExpressions(String infix, String expectedPrefix) {
         assertEquals(expectedPrefix, InfixToPrefix.infix2Prefix(infix));
     }
 

From dba2d869f2f39ecdf7e036c6130f05dbe1377fb6 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sat, 12 Jul 2025 09:51:49 +0300
Subject: [PATCH 0862/1338] refactor: improving `GenericRoot` (#6365)

refactor: improving GenericRoot
---
 .../com/thealgorithms/maths/GenericRoot.java  | 44 +++++++++++++------
 1 file changed, 31 insertions(+), 13 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/GenericRoot.java b/src/main/java/com/thealgorithms/maths/GenericRoot.java
index 07f4756f93f8..e13efe5a77e0 100644
--- a/src/main/java/com/thealgorithms/maths/GenericRoot.java
+++ b/src/main/java/com/thealgorithms/maths/GenericRoot.java
@@ -1,30 +1,48 @@
 package com.thealgorithms.maths;
 
-/*
- * Algorithm explanation:
- * https://technotip.com/6774/c-program-to-find-generic-root-of-a-number/#:~:text=Generic%20Root%3A%20of%20a%20number,get%20a%20single%2Ddigit%20output.&text=For%20Example%3A%20If%20user%20input,%2B%204%20%2B%205%20%3D%2015.
+/**
+ * Calculates the generic root (repeated digital sum) of a non-negative integer.
+ * <p>
+ * For example, the generic root of 12345 is calculated as:
+ * 1 + 2 + 3 + 4 + 5 = 15,
+ * then 1 + 5 = 6, so the generic root is 6.
+ * <p>
+ * Reference:
+ * https://technotip.com/6774/c-program-to-find-generic-root-of-a-number/
  */
 public final class GenericRoot {
+
+    private static final int BASE = 10;
+
     private GenericRoot() {
     }
 
-    private static int base = 10;
-
+    /**
+     * Computes the sum of the digits of a non-negative integer in base 10.
+     *
+     * @param n non-negative integer
+     * @return sum of digits of {@code n}
+     */
     private static int sumOfDigits(final int n) {
         assert n >= 0;
-        if (n < base) {
+        if (n < BASE) {
             return n;
         }
-        return n % base + sumOfDigits(n / base);
+        return (n % BASE) + sumOfDigits(n / BASE);
     }
 
+    /**
+     * Computes the generic root (repeated digital sum) of an integer.
+     * For negative inputs, the absolute value is used.
+     *
+     * @param n integer input
+     * @return generic root of {@code n}
+     */
     public static int genericRoot(final int n) {
-        if (n < 0) {
-            return genericRoot(-n);
-        }
-        if (n > base) {
-            return genericRoot(sumOfDigits(n));
+        int number = Math.abs(n);
+        if (number < BASE) {
+            return number;
         }
-        return n;
+        return genericRoot(sumOfDigits(number));
     }
 }

From 910d5b880ad6187ffdf504732c9fc4baed3ef371 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sun, 13 Jul 2025 12:11:57 +0300
Subject: [PATCH 0863/1338] refactor: Refactor `SJFScheduling` and Tests
 (#6372)

* refactor: Refactor SJFScheduling and Tests

* refactor: fix checkstyle

* refactor: add full imports

* refactor: add full imports

* refactor: remove redundant newline

* refactor: fix indexed list iteration
---
 .../scheduling/SJFScheduling.java             | 109 +++++++---------
 .../scheduling/SJFSchedulingTest.java         | 117 +++++-------------
 2 files changed, 71 insertions(+), 155 deletions(-)

diff --git a/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java b/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
index cbbc65a3afc5..e3f4a8d03d07 100644
--- a/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
+++ b/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java
@@ -2,78 +2,62 @@
 
 import com.thealgorithms.devutils.entities.ProcessDetails;
 import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.Iterator;
 import java.util.List;
 
 /**
- * Implementation of Shortest Job First Algorithm: The algorithm allows the waiting process with the
- * minimal burst time to be executed first. see more here:
- * https://www.guru99.com/shortest-job-first-sjf-scheduling.html
+ * Shortest Job First (SJF) Scheduling Algorithm:
+ * Executes processes with the shortest burst time first among the ones that have arrived.
  */
-
 public class SJFScheduling {
-    protected ArrayList<ProcessDetails> processes;
-    protected ArrayList<String> schedule;
-
-    private static void sortProcessesByArrivalTime(List<ProcessDetails> processes) {
-        for (int i = 0; i < processes.size(); i++) {
-            for (int j = i + 1; j < processes.size() - 1; j++) {
-                if (processes.get(j).getArrivalTime() > processes.get(j + 1).getArrivalTime()) {
-                    final var temp = processes.get(j);
-                    processes.set(j, processes.get(j + 1));
-                    processes.set(j + 1, temp);
-                }
-            }
-        }
-    }
+    private final List<ProcessDetails> processes;
+    private final List<String> schedule;
 
-    /**
-     * a simple constructor
-     * @param processes a list of processes the user wants to schedule
-     *  it also sorts the processes based on the time of their arrival
-     */
-    SJFScheduling(final ArrayList<ProcessDetails> processes) {
-        this.processes = processes;
-        schedule = new ArrayList<>();
+    public SJFScheduling(final List<ProcessDetails> processes) {
+        this.processes = new ArrayList<>(processes);
+        this.schedule = new ArrayList<>();
         sortProcessesByArrivalTime(this.processes);
     }
-    protected void sortByArrivalTime() {
-        sortProcessesByArrivalTime(processes);
+
+    private static void sortProcessesByArrivalTime(List<ProcessDetails> processes) {
+        processes.sort(Comparator.comparingInt(ProcessDetails::getArrivalTime));
     }
 
     /**
-     * this functions returns the order of the executions
+     * Executes the SJF scheduling algorithm and builds the execution order.
      */
-
     public void scheduleProcesses() {
-        ArrayList<ProcessDetails> ready = new ArrayList<>();
-
+        List<ProcessDetails> ready = new ArrayList<>();
         int size = processes.size();
-        int runtime;
         int time = 0;
         int executed = 0;
-        int j;
-        int k = 0;
-        ProcessDetails running;
 
-        if (size == 0) {
-            return;
+        Iterator<ProcessDetails> processIterator = processes.iterator();
+
+        // This will track the next process to be checked for arrival time
+        ProcessDetails nextProcess = null;
+        if (processIterator.hasNext()) {
+            nextProcess = processIterator.next();
         }
 
         while (executed < size) {
-            while (k < size && processes.get(k).getArrivalTime() <= time) // here we find the processes that have arrived.
-            {
-                ready.add(processes.get(k));
-                k++;
+            // Load all processes that have arrived by current time
+            while (nextProcess != null && nextProcess.getArrivalTime() <= time) {
+                ready.add(nextProcess);
+                if (processIterator.hasNext()) {
+                    nextProcess = processIterator.next();
+                } else {
+                    nextProcess = null;
+                }
             }
 
-            running = findShortestJob(ready);
+            ProcessDetails running = findShortestJob(ready);
             if (running == null) {
                 time++;
             } else {
-                runtime = running.getBurstTime();
-                for (j = 0; j < runtime; j++) {
-                    time++;
-                }
+                time += running.getBurstTime();
                 schedule.add(running.getProcessId());
                 ready.remove(running);
                 executed++;
@@ -82,30 +66,23 @@ public void scheduleProcesses() {
     }
 
     /**
-     * this function evaluates the shortest job of all the ready processes (based on  a process
-     * burst time)
+     * Finds the process with the shortest job of all the ready processes (based on  a process
      * @param readyProcesses an array list of ready processes
      * @return returns the process' with the shortest burst time OR NULL if there are no ready
      *     processes
      */
-    private ProcessDetails findShortestJob(List<ProcessDetails> readyProcesses) {
-        if (readyProcesses.isEmpty()) {
-            return null;
-        }
-        int i;
-        int size = readyProcesses.size();
-        int minBurstTime = readyProcesses.get(0).getBurstTime();
-        int temp;
-        int positionOfShortestJob = 0;
+    private ProcessDetails findShortestJob(Collection<ProcessDetails> readyProcesses) {
+        return readyProcesses.stream().min(Comparator.comparingInt(ProcessDetails::getBurstTime)).orElse(null);
+    }
 
-        for (i = 1; i < size; i++) {
-            temp = readyProcesses.get(i).getBurstTime();
-            if (minBurstTime > temp) {
-                minBurstTime = temp;
-                positionOfShortestJob = i;
-            }
-        }
+    /**
+     * Returns the computed schedule after calling scheduleProcesses().
+     */
+    public List<String> getSchedule() {
+        return schedule;
+    }
 
-        return readyProcesses.get(positionOfShortestJob);
+    public List<ProcessDetails> getProcesses() {
+        return List.copyOf(processes);
     }
 }
diff --git a/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java
index aab5c64c847f..660a53299ab0 100644
--- a/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java
+++ b/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java
@@ -4,107 +4,46 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.devutils.entities.ProcessDetails;
-import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class SJFSchedulingTest {
-    private ArrayList<ProcessDetails> process;
-    void initialisation0() {
 
-        process = new ArrayList<>();
-        process.add(new ProcessDetails("1", 0, 6));
-        process.add(new ProcessDetails("2", 1, 2));
+    private static Stream<Arguments> schedulingTestData() {
+        return Stream.of(Arguments.of(List.of(new ProcessDetails("1", 0, 6), new ProcessDetails("2", 1, 2)), List.of("1", "2")),
+            Arguments.of(List.of(new ProcessDetails("1", 0, 6), new ProcessDetails("2", 1, 2), new ProcessDetails("3", 4, 3), new ProcessDetails("4", 3, 1), new ProcessDetails("5", 6, 4), new ProcessDetails("6", 5, 5)), List.of("1", "4", "2", "3", "5", "6")),
+            Arguments.of(List.of(new ProcessDetails("1", 0, 3), new ProcessDetails("2", 1, 2), new ProcessDetails("3", 2, 1)), List.of("1", "3", "2")), Arguments.of(List.of(new ProcessDetails("1", 0, 3), new ProcessDetails("2", 5, 2), new ProcessDetails("3", 9, 1)), List.of("1", "2", "3")),
+            Arguments.of(Collections.emptyList(), List.of()));
     }
-    void initialisation1() {
 
-        process = new ArrayList<>();
-        process.add(new ProcessDetails("1", 0, 6));
-        process.add(new ProcessDetails("2", 1, 2));
-        process.add(new ProcessDetails("3", 4, 3));
-        process.add(new ProcessDetails("4", 3, 1));
-        process.add(new ProcessDetails("5", 6, 4));
-        process.add(new ProcessDetails("6", 5, 5));
-    }
-
-    void initialisation2() {
-
-        process = new ArrayList<>();
-        process.add(new ProcessDetails("1", 0, 3));
-        process.add(new ProcessDetails("2", 1, 2));
-        process.add(new ProcessDetails("3", 2, 1));
-    }
-    void initialisation3() {
-        process = new ArrayList<>();
-        process.add(new ProcessDetails("1", 0, 3));
-        process.add(new ProcessDetails("2", 5, 2));
-        process.add(new ProcessDetails("3", 9, 1));
-    }
-    @Test
-    void constructor() {
-        initialisation0();
-        SJFScheduling a = new SJFScheduling(process);
-        assertEquals(6, a.processes.get(0).getBurstTime());
-        assertEquals(2, a.processes.get(1).getBurstTime());
+    @ParameterizedTest(name = "Test SJF schedule: {index}")
+    @MethodSource("schedulingTestData")
+    void testSJFScheduling(List<ProcessDetails> inputProcesses, List<String> expectedSchedule) {
+        SJFScheduling scheduler = new SJFScheduling(inputProcesses);
+        scheduler.scheduleProcesses();
+        assertEquals(expectedSchedule, scheduler.getSchedule());
     }
 
     @Test
-    void sort() {
-        initialisation1();
-        SJFScheduling a = new SJFScheduling(process);
-        a.sortByArrivalTime();
-        assertEquals("1", a.processes.get(0).getProcessId());
-        assertEquals("2", a.processes.get(1).getProcessId());
-        assertEquals("3", a.processes.get(3).getProcessId());
-        assertEquals("4", a.processes.get(2).getProcessId());
-        assertEquals("5", a.processes.get(5).getProcessId());
-        assertEquals("6", a.processes.get(4).getProcessId());
-    }
+    @DisplayName("Test sorting by arrival order")
+    void testProcessArrivalOrderIsSorted() {
+        List<ProcessDetails> processes = List.of(new ProcessDetails("1", 0, 6), new ProcessDetails("2", 1, 2), new ProcessDetails("4", 3, 1), new ProcessDetails("3", 4, 3), new ProcessDetails("6", 5, 5), new ProcessDetails("5", 6, 4));
+        SJFScheduling scheduler = new SJFScheduling(processes);
+        List<String> actualOrder = scheduler.getProcesses().stream().map(ProcessDetails::getProcessId).toList();
 
-    @Test
-    void scheduling() {
-        initialisation1();
-        SJFScheduling a = new SJFScheduling(process);
-        a.scheduleProcesses();
-        assertEquals("1", a.schedule.get(0));
-        assertEquals("4", a.schedule.get(1));
-        assertEquals("2", a.schedule.get(2));
-        assertEquals("3", a.schedule.get(3));
-        assertEquals("5", a.schedule.get(4));
-        assertEquals("6", a.schedule.get(5));
+        assertEquals(List.of("1", "2", "4", "3", "6", "5"), actualOrder);
     }
 
     @Test
-    void schedulingOfTwoProcesses() {
-        initialisation0();
-        SJFScheduling a = new SJFScheduling(process);
-        a.scheduleProcesses();
-        assertEquals("1", a.schedule.get(0));
-        assertEquals("2", a.schedule.get(1));
-    }
-
-    @Test
-    void schedulingOfAShortestJobArrivingLast() {
-        initialisation2();
-        SJFScheduling a = new SJFScheduling(process);
-        a.scheduleProcesses();
-        assertEquals("1", a.schedule.get(0));
-        assertEquals("3", a.schedule.get(1));
-        assertEquals("2", a.schedule.get(2));
-    }
-    @Test
-    void schedulingWithProcessesNotComingBackToBack() {
-        initialisation3();
-        SJFScheduling a = new SJFScheduling(process);
-        a.scheduleProcesses();
-        assertEquals("1", a.schedule.get(0));
-        assertEquals("2", a.schedule.get(1));
-        assertEquals("3", a.schedule.get(2));
-    }
-    @Test
-    void schedulingOfNothing() {
-        process = new ArrayList<>();
-        SJFScheduling a = new SJFScheduling(process);
-        a.scheduleProcesses();
-        assertTrue(a.schedule.isEmpty());
+    void testSchedulingEmptyList() {
+        SJFScheduling scheduler = new SJFScheduling(Collections.emptyList());
+        scheduler.scheduleProcesses();
+        assertTrue(scheduler.getSchedule().isEmpty());
     }
 }

From 182118b6a44bd482e6c14b662b63fcd068dae9cb Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sun, 13 Jul 2025 12:17:38 +0300
Subject: [PATCH 0864/1338] refactor: cleanup `GenerateSubsets` (#6373)

refactor: cleanup GenerateSubsets

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../recursion/GenerateSubsets.java            | 50 ++++++++++++-------
 1 file changed, 33 insertions(+), 17 deletions(-)

diff --git a/src/main/java/com/thealgorithms/recursion/GenerateSubsets.java b/src/main/java/com/thealgorithms/recursion/GenerateSubsets.java
index 5a3ff2e88040..0114a55e5b75 100644
--- a/src/main/java/com/thealgorithms/recursion/GenerateSubsets.java
+++ b/src/main/java/com/thealgorithms/recursion/GenerateSubsets.java
@@ -1,36 +1,52 @@
 package com.thealgorithms.recursion;
 
-// program to find power set of a string
-
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Utility class to generate all subsets (power set) of a given string using recursion.
+ *
+ * <p>For example, the string "ab" will produce: ["ab", "a", "b", ""]
+ */
 public final class GenerateSubsets {
 
     private GenerateSubsets() {
-        throw new UnsupportedOperationException("Utility class");
     }
 
+    /**
+     * Generates all subsets (power set) of the given string using recursion.
+     *
+     * @param str the input string to generate subsets for
+     * @return a list of all subsets of the input string
+     */
     public static List<String> subsetRecursion(String str) {
-        return doRecursion("", str);
+        return generateSubsets("", str);
     }
 
-    private static List<String> doRecursion(String p, String up) {
-        if (up.isEmpty()) {
-            List<String> list = new ArrayList<>();
-            list.add(p);
-            return list;
+    /**
+     * Recursive helper method to generate subsets by including or excluding characters.
+     *
+     * @param current the current prefix being built
+     * @param remaining the remaining string to process
+     * @return list of subsets formed from current and remaining
+     */
+    private static List<String> generateSubsets(String current, String remaining) {
+        if (remaining.isEmpty()) {
+            List<String> result = new ArrayList<>();
+            result.add(current);
+            return result;
         }
 
-        // Taking the character
-        char ch = up.charAt(0);
-        // Adding the character in the recursion
-        List<String> left = doRecursion(p + ch, up.substring(1));
-        // Not adding the character in the recursion
-        List<String> right = doRecursion(p, up.substring(1));
+        char ch = remaining.charAt(0);
+        String next = remaining.substring(1);
+
+        // Include the character
+        List<String> withChar = generateSubsets(current + ch, next);
 
-        left.addAll(right);
+        // Exclude the character
+        List<String> withoutChar = generateSubsets(current, next);
 
-        return left;
+        withChar.addAll(withoutChar);
+        return withChar;
     }
 }

From ef93cc15038aefd29ff3cb4ae2a0fb0df466a767 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sun, 13 Jul 2025 12:25:26 +0300
Subject: [PATCH 0865/1338] refactor: `TwoPointers` (#6374)

* refactor: TwoPointers

* refactor: fix test formatting

* refactor: fix checkstyle

* refactor: fix checkstyle
---
 .../com/thealgorithms/others/TwoPointers.java | 33 +++++++++++--------
 .../thealgorithms/others/TwoPointersTest.java |  8 +++++
 2 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/TwoPointers.java b/src/main/java/com/thealgorithms/others/TwoPointers.java
index c551408c38b9..c87e26269386 100644
--- a/src/main/java/com/thealgorithms/others/TwoPointers.java
+++ b/src/main/java/com/thealgorithms/others/TwoPointers.java
@@ -7,30 +7,37 @@
  * <p>
  * Link: https://www.geeksforgeeks.org/two-pointers-technique/
  */
-final class TwoPointers {
+public final class TwoPointers {
+
     private TwoPointers() {
     }
 
     /**
-     * Given a sorted array arr (sorted in ascending order), find if there exists
-     * any pair of elements such that their sum is equal to the key.
+     * Checks whether there exists a pair of elements in a sorted array whose sum equals the specified key.
      *
-     * @param arr the array containing elements (must be sorted in ascending order)
-     * @param key the number to search
-     * @return {@code true} if there exists a pair of elements, {@code false} otherwise.
+     * @param arr a sorted array of integers in ascending order (must not be null)
+     * @param key the target sum to find
+     * @return {@code true} if there exists at least one pair whose sum equals {@code key}, {@code false} otherwise
+     * @throws IllegalArgumentException if {@code arr} is {@code null}
      */
     public static boolean isPairedSum(int[] arr, int key) {
-        int i = 0; // index of the first element
-        int j = arr.length - 1; // index of the last element
+        if (arr == null) {
+            throw new IllegalArgumentException("Input array must not be null.");
+        }
+
+        int left = 0;
+        int right = arr.length - 1;
+
+        while (left < right) {
+            int sum = arr[left] + arr[right];
 
-        while (i < j) {
-            int sum = arr[i] + arr[j];
             if (sum == key) {
                 return true;
-            } else if (sum < key) {
-                i++;
+            }
+            if (sum < key) {
+                left++;
             } else {
-                j--;
+                right--;
             }
         }
         return false;
diff --git a/src/test/java/com/thealgorithms/others/TwoPointersTest.java b/src/test/java/com/thealgorithms/others/TwoPointersTest.java
index 3a174e0cd19e..6e0d2b22d280 100644
--- a/src/test/java/com/thealgorithms/others/TwoPointersTest.java
+++ b/src/test/java/com/thealgorithms/others/TwoPointersTest.java
@@ -1,6 +1,8 @@
 package com.thealgorithms.others;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
@@ -69,4 +71,10 @@ void testPairExistsAtEdges() {
         int key = 9;
         assertTrue(TwoPointers.isPairedSum(arr, key));
     }
+
+    @Test
+    void isPairedSumShouldThrowExceptionWhenArrayIsNull() {
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> TwoPointers.isPairedSum(null, 10));
+        assertEquals("Input array must not be null.", exception.getMessage());
+    }
 }

From 933e929b5407fdd69a197cf7821579c14a456a5e Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Mon, 14 Jul 2025 08:47:22 +0300
Subject: [PATCH 0866/1338] refactor: refactor `Ceil` and improved tests
 (#6366)

* refactor: refactor Ceil and improved tests

* checkstyle: remove redundant import

* refactor: fix edge cases

* refactor: fix checkstyle

* refactor: fix checkstyle import order
---
 .../java/com/thealgorithms/maths/Ceil.java    | 27 ++++++++++++-----
 .../com/thealgorithms/maths/CeilTest.java     | 30 ++++++++++++++-----
 2 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Ceil.java b/src/main/java/com/thealgorithms/maths/Ceil.java
index aacb9d969950..28804eb1c569 100644
--- a/src/main/java/com/thealgorithms/maths/Ceil.java
+++ b/src/main/java/com/thealgorithms/maths/Ceil.java
@@ -1,23 +1,34 @@
 package com.thealgorithms.maths;
 
+/**
+ * Utility class to compute the ceiling of a given number.
+ */
 public final class Ceil {
+
     private Ceil() {
     }
 
     /**
-     * Returns the smallest (closest to negative infinity)
+     * Returns the smallest double value that is greater than or equal to the input.
+     * Equivalent to mathematical ⌈x⌉ (ceiling function).
      *
-     * @param number the number
-     * @return the smallest (closest to negative infinity) of given
-     * {@code number}
+     * @param number the number to ceil
+     * @return the smallest double greater than or equal to {@code number}
      */
     public static double ceil(double number) {
-        if (number - (int) number == 0) {
+        if (Double.isNaN(number) || Double.isInfinite(number) || number == 0.0 || number < Integer.MIN_VALUE || number > Integer.MAX_VALUE) {
             return number;
-        } else if (number - (int) number > 0) {
-            return (int) (number + 1);
+        }
+
+        if (number < 0.0 && number > -1.0) {
+            return -0.0;
+        }
+
+        long intPart = (long) number;
+        if (number > 0 && number != intPart) {
+            return intPart + 1.0;
         } else {
-            return (int) number;
+            return intPart;
         }
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/CeilTest.java b/src/test/java/com/thealgorithms/maths/CeilTest.java
index 5596760a8c40..ddd0deed41d3 100644
--- a/src/test/java/com/thealgorithms/maths/CeilTest.java
+++ b/src/test/java/com/thealgorithms/maths/CeilTest.java
@@ -2,16 +2,30 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class CeilTest {
 
-    @Test
-    void testCeil() {
-        assertEquals(8, Ceil.ceil(7.057));
-        assertEquals(8, Ceil.ceil(7.004));
-        assertEquals(-13, Ceil.ceil(-13.004));
-        assertEquals(1, Ceil.ceil(.98));
-        assertEquals(-11, Ceil.ceil(-11.357));
+    @ParameterizedTest
+    @CsvSource({"7.057, 8", "7.004, 8", "-13.004, -13", "0.98, 1", "-11.357, -11"})
+    void testCeil(double input, int expected) {
+        assertEquals(expected, Ceil.ceil(input));
+    }
+
+    @ParameterizedTest
+    @MethodSource("edgeCaseProvider")
+    void testEdgeCases(TestData data) {
+        assertEquals(Ceil.ceil(data.input), data.expected);
+    }
+
+    record TestData(double input, double expected) {
+    }
+
+    static Stream<TestData> edgeCaseProvider() {
+        return Stream.of(new TestData(Double.MAX_VALUE, Double.MAX_VALUE), new TestData(Double.MIN_VALUE, Math.ceil(Double.MIN_VALUE)), new TestData(0.0, Math.ceil(0.0)), new TestData(-0.0, Math.ceil(-0.0)), new TestData(Double.NaN, Math.ceil(Double.NaN)),
+            new TestData(Double.NEGATIVE_INFINITY, Math.ceil(Double.NEGATIVE_INFINITY)), new TestData(Double.POSITIVE_INFINITY, Math.ceil(Double.POSITIVE_INFINITY)));
     }
 }

From 25aaa6e06448f9f5100570287e3776e159f20470 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Mon, 14 Jul 2025 08:51:17 +0300
Subject: [PATCH 0867/1338] refactor: `OnesComplement` Tests Using
 Parameterized Inputs (#6375)

refactor: OnesComplement Tests Using Parameterized Inputs

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../bitmanipulation/OnesComplement.java       | 25 +++++++++++++------
 .../bitmanipulation/OnesComplementTest.java   | 17 ++++++++++---
 2 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java b/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java
index c5c068422113..aae3a996e49d 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java
@@ -12,15 +12,24 @@ public final class OnesComplement {
     private OnesComplement() {
     }
 
-    // Function to get the 1's complement of a binary number
+    /**
+     * Returns the 1's complement of a binary string.
+     *
+     * @param binary A string representing a binary number (e.g., "1010").
+     * @return A string representing the 1's complement.
+     * @throws IllegalArgumentException if the input is null or contains characters other than '0' or '1'.
+     */
     public static String onesComplement(String binary) {
-        StringBuilder complement = new StringBuilder();
-        // Invert each bit to get the 1's complement
-        for (int i = 0; i < binary.length(); i++) {
-            if (binary.charAt(i) == '0') {
-                complement.append('1');
-            } else {
-                complement.append('0');
+        if (binary == null || binary.isEmpty()) {
+            throw new IllegalArgumentException("Input must be a non-empty binary string.");
+        }
+
+        StringBuilder complement = new StringBuilder(binary.length());
+        for (char bit : binary.toCharArray()) {
+            switch (bit) {
+                case '0' -> complement.append('1');
+                case '1' -> complement.append('0');
+                default -> throw new IllegalArgumentException("Input must contain only '0' and '1'. Found: " + bit);
             }
         }
         return complement.toString();
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java b/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java
index 6be4eb595f79..0e90ed79f587 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/OnesComplementTest.java
@@ -1,8 +1,12 @@
 package com.thealgorithms.bitmanipulation;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.NullAndEmptySource;
 
 /**
  * Test case for Highest Set Bit
@@ -39,9 +43,16 @@ public void testOnesComplementMixedBits() {
         assertEquals("1001", OnesComplement.onesComplement("0110"));
     }
 
+    @ParameterizedTest
+    @NullAndEmptySource
+    public void testOnesComplementNullOrEmptyInputThrowsException(String input) {
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> OnesComplement.onesComplement(input));
+        assertEquals("Input must be a non-empty binary string.", exception.getMessage());
+    }
+
     @Test
-    public void testOnesComplementEmptyString() {
-        // Test empty string scenario
-        assertEquals("", OnesComplement.onesComplement(""));
+    public void testOnesComplementInvalidCharactersThrowsException() {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> OnesComplement.onesComplement("10a1"));
+        assertTrue(exception.getMessage().startsWith("Input must contain only '0' and '1'"));
     }
 }

From 95116dbee417bc83a16d274ba13ebd941980b122 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Tue, 15 Jul 2025 08:23:49 +0300
Subject: [PATCH 0868/1338] refactor: improving `MedianOfMatrix` (#6376)

refactor: improving MedianOfMatrix
---
 .../thealgorithms/matrix/MedianOfMatrix.java  | 20 +++++++++----------
 .../matrix/MedianOfMatrixTest.java            | 16 +++++++++++++++
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java b/src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java
index c710c60a2d2a..1ec977af07c6 100644
--- a/src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java
+++ b/src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java
@@ -14,19 +14,19 @@ private MedianOfMatrix() {
     }
 
     public static int median(Iterable<List<Integer>> matrix) {
-        // Flatten the matrix into a 1D list
-        List<Integer> linear = new ArrayList<>();
+        List<Integer> flattened = new ArrayList<>();
+
         for (List<Integer> row : matrix) {
-            linear.addAll(row);
+            if (row != null) {
+                flattened.addAll(row);
+            }
         }
 
-        // Sort the 1D list
-        Collections.sort(linear);
-
-        // Calculate the middle index
-        int mid = (0 + linear.size() - 1) / 2;
+        if (flattened.isEmpty()) {
+            throw new IllegalArgumentException("Matrix must contain at least one element.");
+        }
 
-        // Return the median
-        return linear.get(mid);
+        Collections.sort(flattened);
+        return flattened.get((flattened.size() - 1) / 2);
     }
 }
diff --git a/src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java b/src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java
index db66bb2d187b..b9b97014f3fc 100644
--- a/src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java
+++ b/src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java
@@ -1,9 +1,11 @@
 package com.thealgorithms.matrix;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
@@ -31,4 +33,18 @@ public void testMedianWithEvenNumberOfElements() {
 
         assertEquals(2, result);
     }
+
+    @Test
+    public void testMedianSingleElement() {
+        List<List<Integer>> matrix = new ArrayList<>();
+        matrix.add(List.of(1));
+
+        assertEquals(1, MedianOfMatrix.median(matrix));
+    }
+
+    @Test
+    void testEmptyMatrixThrowsException() {
+        Iterable<List<Integer>> emptyMatrix = Collections.emptyList();
+        assertThrows(IllegalArgumentException.class, () -> MedianOfMatrix.median(emptyMatrix), "Expected median() to throw, but it didn't");
+    }
 }

From 7e37d94c538dc376be8cd3672ca6711bba75cc1e Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Tue, 15 Jul 2025 08:26:49 +0300
Subject: [PATCH 0869/1338] refactor: improving readability
 `DecimalToAnyUsingStack` (#6377)

refactor: improving readability DecimalToAnyUsingStack

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../SubsetSumSpaceOptimized.java              | 48 ++++++++++---------
 .../stacks/DecimalToAnyUsingStack.java        | 29 +++++++----
 2 files changed, 46 insertions(+), 31 deletions(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java
index 946da46cb292..5c0167977ae4 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java
@@ -1,35 +1,39 @@
 package com.thealgorithms.dynamicprogramming;
-/*
-The Sum of Subset problem determines whether a subset of elements from a
-given array sums up to a specific target value.
-*/
+
+/**
+ * Utility class for solving the Subset Sum problem using a space-optimized dynamic programming approach.
+ *
+ * <p>This algorithm determines whether any subset of a given array sums up to a specific target value.</p>
+ *
+ * <p><b>Time Complexity:</b> O(n * sum)</p>
+ * <p><b>Space Complexity:</b> O(sum)</p>
+ */
 public final class SubsetSumSpaceOptimized {
     private SubsetSumSpaceOptimized() {
     }
+
     /**
-     * This method checks whether the subset of an array
-     * contains a given sum or not. This is an space
-     * optimized solution using 1D boolean array
-     * Time Complexity: O(n * sum), Space complexity: O(sum)
+     * Determines whether there exists a subset of the given array that adds up to the specified sum.
+     * This method uses a space-optimized dynamic programming approach with a 1D boolean array.
      *
-     * @param arr An array containing integers
-     * @param sum The target sum of the subset
-     * @return True or False
+     * @param nums The array of non-negative integers
+     * @param targetSum The desired subset sum
+     * @return {@code true} if such a subset exists, {@code false} otherwise
      */
-    public static boolean isSubsetSum(int[] arr, int sum) {
-        int n = arr.length;
-        // Declare the boolean array with size sum + 1
-        boolean[] dp = new boolean[sum + 1];
+    public static boolean isSubsetSum(int[] nums, int targetSum) {
+        if (targetSum < 0) {
+            return false; // Subset sum can't be negative
+        }
 
-        // Initialize the first element as true
-        dp[0] = true;
+        boolean[] dp = new boolean[targetSum + 1];
+        dp[0] = true; // Empty subset always sums to 0
 
-        // Find the subset sum using 1D array
-        for (int i = 0; i < n; i++) {
-            for (int j = sum; j >= arr[i]; j--) {
-                dp[j] = dp[j] || dp[j - arr[i]];
+        for (int number : nums) {
+            for (int j = targetSum; j >= number; j--) {
+                dp[j] = dp[j] || dp[j - number];
             }
         }
-        return dp[sum];
+
+        return dp[targetSum];
     }
 }
diff --git a/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java b/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java
index ff6402c92695..2852454fd096 100644
--- a/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java
+++ b/src/main/java/com/thealgorithms/stacks/DecimalToAnyUsingStack.java
@@ -2,17 +2,29 @@
 
 import java.util.Stack;
 
+/**
+ * Utility class for converting a non-negative decimal (base-10) integer
+ * to its representation in another radix (base) between 2 and 16, inclusive.
+ *
+ * <p>This class uses a stack-based approach to reverse the digits obtained from
+ * successive divisions by the target radix.
+ *
+ * <p>This class cannot be instantiated.</p>
+ */
 public final class DecimalToAnyUsingStack {
+
     private DecimalToAnyUsingStack() {
     }
 
+    private static final char[] DIGITS = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
+
     /**
      * Convert a decimal number to another radix.
      *
      * @param number the number to be converted
      * @param radix the radix
      * @return the number represented in the new radix as a String
-     * @throws IllegalArgumentException if <tt>number</tt> is negative or <tt>radix</tt> is not between 2 and 16 inclusive
+     * @throws IllegalArgumentException if number is negative or radix is not between 2 and 16 inclusive
      */
     public static String convert(int number, int radix) {
         if (number < 0) {
@@ -26,18 +38,17 @@ public static String convert(int number, int radix) {
             return "0";
         }
 
-        char[] tables = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
-
-        Stack<Character> bits = new Stack<>();
+        Stack<Character> digitStack = new Stack<>();
         while (number > 0) {
-            bits.push(tables[number % radix]);
-            number = number / radix;
+            digitStack.push(DIGITS[number % radix]);
+            number /= radix;
         }
 
-        StringBuilder result = new StringBuilder();
-        while (!bits.isEmpty()) {
-            result.append(bits.pop());
+        StringBuilder result = new StringBuilder(digitStack.size());
+        while (!digitStack.isEmpty()) {
+            result.append(digitStack.pop());
         }
+
         return result.toString();
     }
 }

From ca7c77f16bf59a338adb5e41486387c982b38387 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Tue, 15 Jul 2025 08:31:09 +0300
Subject: [PATCH 0870/1338] refactor: improving `DisjointSetUnion` (#6378)

* refactor: improving DisjointSetUnion

* refactor: remove comment as it already in description

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../disjointsetunion/DisjointSetUnion.java    | 64 +++++++++++--------
 1 file changed, 38 insertions(+), 26 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java b/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java
index 583800998c81..55951be82c8a 100644
--- a/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java
+++ b/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java
@@ -1,53 +1,65 @@
 package com.thealgorithms.datastructures.disjointsetunion;
 
 /**
- * Disjoint Set Union or DSU is useful for solving problems related to connected components,
- * cycle detection in graphs, and maintaining relationships in disjoint sets of data.
- * It is commonly employed in graph algorithms and problems.
+ * Disjoint Set Union (DSU), also known as Union-Find, is a data structure that tracks a set of elements
+ * partitioned into disjoint (non-overlapping) subsets. It supports two primary operations efficiently:
  *
- * @see <a href="https://en.wikipedia.org/wiki/Disjoint-set_data_structure">Disjoint Set Union</a>
+ * <ul>
+ *     <li>Find: Determine which subset a particular element belongs to.</li>
+ *     <li>Union: Merge two subsets into a single subset.</li>
+ * </ul>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Disjoint-set_data_structure">Disjoint Set Union (Wikipedia)</a>
  */
 public class DisjointSetUnion<T> {
 
     /**
-     * Creates a new node of DSU with parent initialised as same node
+     * Creates a new disjoint set containing the single specified element.
+     *
+     * @param value the element to be placed in a new singleton set
+     * @return a node representing the new set
      */
-    public Node<T> makeSet(final T x) {
-        return new Node<T>(x);
+    public Node<T> makeSet(final T value) {
+        return new Node<>(value);
     }
 
     /**
-     * Finds and returns the representative (root) element of the set to which a given element belongs.
-     * This operation uses path compression to optimize future findSet operations.
+     * Finds and returns the representative (root) of the set containing the given node.
+     * This method applies path compression to flatten the tree structure for future efficiency.
+     *
+     * @param node the node whose set representative is to be found
+     * @return the representative (root) node of the set
      */
     public Node<T> findSet(Node<T> node) {
-        while (node != node.parent) {
-            node = node.parent;
+        if (node != node.parent) {
+            node.parent = findSet(node.parent);
         }
-        return node;
+        return node.parent;
     }
 
     /**
-     * Unions two sets by merging their representative elements. The merge is performed based on the rank of each set
-     * to ensure efficient merging and path compression to optimize future findSet operations.
+     * Merges the sets containing the two given nodes. Union by rank is used to attach the smaller tree under the larger one.
+     * If both sets have the same rank, one becomes the parent and its rank is incremented.
+     *
+     * @param x a node in the first set
+     * @param y a node in the second set
      */
-    public void unionSets(final Node<T> x, final Node<T> y) {
-        Node<T> nx = findSet(x);
-        Node<T> ny = findSet(y);
+    public void unionSets(Node<T> x, Node<T> y) {
+        Node<T> rootX = findSet(x);
+        Node<T> rootY = findSet(y);
 
-        if (nx == ny) {
-            return; // Both elements already belong to the same set.
+        if (rootX == rootY) {
+            return; // They are already in the same set
         }
         // Merging happens based on rank of node, this is done to avoid long chaining of nodes and reduce time
         // to find root of the component. Idea is to attach small components in big, instead of other way around.
-        if (nx.rank > ny.rank) {
-            ny.parent = nx;
-        } else if (ny.rank > nx.rank) {
-            nx.parent = ny;
+        if (rootX.rank > rootY.rank) {
+            rootY.parent = rootX;
+        } else if (rootY.rank > rootX.rank) {
+            rootX.parent = rootY;
         } else {
-            // Both sets have the same rank; choose one as the parent and increment the rank.
-            ny.parent = nx;
-            nx.rank++;
+            rootY.parent = rootX;
+            rootX.rank++;
         }
     }
 }

From 287a708c7fec2d60455bd786b7b258028532ed2e Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Tue, 15 Jul 2025 18:04:58 +0300
Subject: [PATCH 0871/1338] refactor: `Intersection` (#6379)

refactor: Intersection improvement
---
 .../hashmap/hashing/Intersection.java         | 58 ++++++++++---------
 1 file changed, 32 insertions(+), 26 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java
index 0e49218d6348..5760d39f1df7 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java
@@ -8,60 +8,66 @@
 
 /**
  * The {@code Intersection} class provides a method to compute the intersection of two integer arrays.
- * The intersection is defined as the set of common elements present in both arrays.
  * <p>
- * This class utilizes a HashMap to efficiently count occurrences of elements in the first array,
- * allowing for an efficient lookup of common elements in the second array.
+ * This intersection includes duplicate values — meaning elements are included in the result
+ * as many times as they appear in both arrays (i.e., multiset intersection).
  * </p>
  *
  * <p>
- * Example:
- * <pre>
+ * The algorithm uses a {@link java.util.HashMap} to count occurrences of elements in the first array,
+ * then iterates through the second array to collect common elements based on these counts.
+ * </p>
+ *
+ * <p>
+ * Example usage:
+ * <pre>{@code
  * int[] array1 = {1, 2, 2, 1};
  * int[] array2 = {2, 2};
- * List<Integer> result = Intersection.intersection(array1, array2); // result will contain [2, 2]
- * </pre>
+ * List<Integer> result = Intersection.intersection(array1, array2); // result: [2, 2]
+ * }</pre>
  * </p>
  *
  * <p>
- * Note: The order of the returned list may vary since it depends on the order of elements
- * in the input arrays.
+ * Note: The order of elements in the returned list depends on the order in the second input array.
  * </p>
  */
 public final class Intersection {
 
+    private Intersection() {
+        // Utility class; prevent instantiation
+    }
+
     /**
-     * Computes the intersection of two integer arrays.
+     * Computes the intersection of two integer arrays, preserving element frequency.
+     * For example, given [1,2,2,3] and [2,2,4], the result will be [2,2].
+     *
      * Steps:
-     * 1. Count the occurrences of each element in the first array using a HashMap.
-     * 2. Iterate over the second array and check if the element is present in the HashMap.
-     * If it is, add it to the result list and decrement the count in the HashMap.
-     * 3. Return the result list containing the intersection of the two arrays.
+     * 1. Count the occurrences of each element in the first array using a map.
+     * 2. Iterate over the second array and collect common elements.
      *
      * @param arr1 the first array of integers
      * @param arr2 the second array of integers
-     * @return a list containing the intersection of the two arrays, or an empty list if either array is null or empty
+     * @return a list containing the intersection of the two arrays (with duplicates),
+     *         or an empty list if either array is null or empty
      */
     public static List<Integer> intersection(int[] arr1, int[] arr2) {
         if (arr1 == null || arr2 == null || arr1.length == 0 || arr2.length == 0) {
             return Collections.emptyList();
         }
 
-        Map<Integer, Integer> cnt = new HashMap<>(16);
-        for (int v : arr1) {
-            cnt.put(v, cnt.getOrDefault(v, 0) + 1);
+        Map<Integer, Integer> countMap = new HashMap<>();
+        for (int num : arr1) {
+            countMap.put(num, countMap.getOrDefault(num, 0) + 1);
         }
 
-        List<Integer> res = new ArrayList<>();
-        for (int v : arr2) {
-            if (cnt.containsKey(v) && cnt.get(v) > 0) {
-                res.add(v);
-                cnt.put(v, cnt.get(v) - 1);
+        List<Integer> result = new ArrayList<>();
+        for (int num : arr2) {
+            if (countMap.getOrDefault(num, 0) > 0) {
+                result.add(num);
+                countMap.computeIfPresent(num, (k, v) -> v - 1);
             }
         }
-        return res;
-    }
 
-    private Intersection() {
+        return result;
     }
 }

From dcb02c61dfadd6cab986c44c2999aec7fea7076a Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Tue, 15 Jul 2025 18:10:06 +0300
Subject: [PATCH 0872/1338] refactor: `MajorityElement` (#6380)

* refactor: MajorityElement

* refactor: fix import ordering

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../hashmap/hashing/MajorityElement.java              | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
index 915e4228b618..5fd6b2e7f3cb 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElement.java
@@ -1,8 +1,10 @@
 package com.thealgorithms.datastructures.hashmap.hashing;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 /**
  * This class provides a method to find the majority element(s) in an array of integers.
@@ -18,13 +20,18 @@ private MajorityElement() {
      * Returns a list of majority element(s) from the given array of integers.
      *
      * @param nums an array of integers
-     * @return a list containing the majority element(s); returns an empty list if none exist
+     * @return a list containing the majority element(s); returns an empty list if none exist or input is null/empty
      */
     public static List<Integer> majority(int[] nums) {
-        HashMap<Integer, Integer> numToCount = new HashMap<>();
+        if (nums == null || nums.length == 0) {
+            return Collections.emptyList();
+        }
+
+        Map<Integer, Integer> numToCount = new HashMap<>();
         for (final var num : nums) {
             numToCount.merge(num, 1, Integer::sum);
         }
+
         List<Integer> majorityElements = new ArrayList<>();
         for (final var entry : numToCount.entrySet()) {
             if (entry.getValue() >= nums.length / 2) {

From d55e89dc71284cefe0e75bde8c9ecaa2496deac7 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Wed, 16 Jul 2025 18:02:16 +0300
Subject: [PATCH 0873/1338] refactor: `Mode` (#6381)

refactor: Mode
---
 .../java/com/thealgorithms/maths/Mode.java    | 37 ++++++++++---------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Mode.java b/src/main/java/com/thealgorithms/maths/Mode.java
index f0b747cf02ec..657f8ece2a50 100644
--- a/src/main/java/com/thealgorithms/maths/Mode.java
+++ b/src/main/java/com/thealgorithms/maths/Mode.java
@@ -3,46 +3,49 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 
-/*
- * Find the mode of an array of numbers
- *
- * The mode of an array of numbers is the most frequently occurring number in the array,
- * or the most frequently occurring numbers if there are multiple numbers with the same frequency
+/**
+ * Utility class to calculate the mode(s) of an array of integers.
+ * <p>
+ * The mode of an array is the integer value(s) that occur most frequently.
+ * If multiple values have the same highest frequency, all such values are returned.
+ * </p>
  */
 public final class Mode {
     private Mode() {
     }
 
-    /*
-     * Find the mode of an array of integers
+    /**
+     * Computes the mode(s) of the specified array of integers.
+     * <p>
+     * If the input array is empty, this method returns {@code null}.
+     * If multiple numbers share the highest frequency, all are returned in the result array.
+     * </p>
      *
-     * @param numbers array of integers
-     * @return mode of the array
+     * @param numbers an array of integers to analyze
+     * @return an array containing the mode(s) of the input array, or {@code null} if the input is empty
      */
     public static int[] mode(final int[] numbers) {
         if (numbers.length == 0) {
             return null;
         }
 
-        HashMap<Integer, Integer> count = new HashMap<>();
+        Map<Integer, Integer> count = new HashMap<>();
 
         for (int num : numbers) {
-            if (count.containsKey(num)) {
-                count.put(num, count.get(num) + 1);
-            } else {
-                count.put(num, 1);
-            }
+            count.put(num, count.getOrDefault(num, 0) + 1);
         }
 
         int max = Collections.max(count.values());
-        ArrayList<Integer> modes = new ArrayList<>();
+        List<Integer> modes = new ArrayList<>();
 
         for (final var entry : count.entrySet()) {
             if (entry.getValue() == max) {
                 modes.add(entry.getKey());
             }
         }
-        return modes.stream().mapToInt(n -> n).toArray();
+        return modes.stream().mapToInt(Integer::intValue).toArray();
     }
 }

From 434ab50ff4d34c50e19a39f4a4d1f3a4df459e22 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Wed, 16 Jul 2025 18:05:13 +0300
Subject: [PATCH 0874/1338] refactor: `Convolution` (#6382)

refactor: Convolution

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../com/thealgorithms/maths/Convolution.java  | 25 ++++++++-----------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Convolution.java b/src/main/java/com/thealgorithms/maths/Convolution.java
index 93e103f8c7cf..a86ecabce933 100644
--- a/src/main/java/com/thealgorithms/maths/Convolution.java
+++ b/src/main/java/com/thealgorithms/maths/Convolution.java
@@ -23,24 +23,21 @@ public static double[] convolution(double[] a, double[] b) {
         double[] convolved = new double[a.length + b.length - 1];
 
         /*
-    The discrete convolution of two signals A and B is defined as:
-
-          A.length
-    C[i] = Σ (A[k]*B[i-k])
-          k=0
-
-    It's obvious that:  0 <= k <= A.length , 0 <= i <= A.length + B.length - 2  and  0 <= i-k <=
-    B.length - 1 From the last inequality we get that:  i - B.length + 1 <= k <= i and thus we get
-    the conditions below.
+         * Discrete convolution formula:
+         * C[i] = Σ A[k] * B[i - k]
+         * where k ranges over valid indices so that both A[k] and B[i-k] are in bounds.
          */
+
         for (int i = 0; i < convolved.length; i++) {
-            convolved[i] = 0;
-            int k = Math.max(i - b.length + 1, 0);
+            double sum = 0;
+            int kStart = Math.max(0, i - b.length + 1);
+            int kEnd = Math.min(i, a.length - 1);
 
-            while (k < i + 1 && k < a.length) {
-                convolved[i] += a[k] * b[i - k];
-                k++;
+            for (int k = kStart; k <= kEnd; k++) {
+                sum += a[k] * b[i - k];
             }
+
+            convolved[i] = sum;
         }
 
         return convolved;

From dd1a51b20f15eac49365d154b479c5848021c8f9 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Wed, 16 Jul 2025 18:10:22 +0300
Subject: [PATCH 0875/1338] testing: add more cases for `AverageTest` (#6384)

* testing: add more cases for AverageTest

* checkstyle: fix formatting
---
 .../com/thealgorithms/maths/AverageTest.java  | 45 ++++++++++++-------
 1 file changed, 30 insertions(+), 15 deletions(-)

diff --git a/src/test/java/com/thealgorithms/maths/AverageTest.java b/src/test/java/com/thealgorithms/maths/AverageTest.java
index c5c751938f5d..638739bc4fda 100644
--- a/src/test/java/com/thealgorithms/maths/AverageTest.java
+++ b/src/test/java/com/thealgorithms/maths/AverageTest.java
@@ -1,33 +1,48 @@
 package com.thealgorithms.maths;
 
-import org.junit.jupiter.api.Assertions;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class AverageTest {
 
     private static final double SMALL_VALUE = 0.00001d;
 
-    @Test
-    public void testAverageDouble12() {
-        double[] numbers = {3d, 6d, 9d, 12d, 15d, 18d, 21d};
-        Assertions.assertEquals(12d, Average.average(numbers), SMALL_VALUE);
+    @ParameterizedTest(name = "average({0}) should be approximately {1}")
+    @MethodSource("provideDoubleArrays")
+    void testAverageDouble(double[] numbers, double expected) {
+        assertEquals(expected, Average.average(numbers), SMALL_VALUE);
     }
 
-    @Test
-    public void testAverageDouble20() {
-        double[] numbers = {5d, 10d, 15d, 20d, 25d, 30d, 35d};
-        Assertions.assertEquals(20d, Average.average(numbers), SMALL_VALUE);
+    @ParameterizedTest(name = "average({0}) should be {1}")
+    @MethodSource("provideIntArrays")
+    void testAverageInt(int[] numbers, long expected) {
+        assertEquals(expected, Average.average(numbers));
     }
 
     @Test
-    public void testAverageDouble() {
-        double[] numbers = {1d, 2d, 3d, 4d, 5d, 6d, 7d, 8d};
-        Assertions.assertEquals(4.5d, Average.average(numbers), SMALL_VALUE);
+    void testAverageDoubleThrowsExceptionOnNullOrEmpty() {
+        assertThrows(IllegalArgumentException.class, () -> Average.average((double[]) null));
+        assertThrows(IllegalArgumentException.class, () -> Average.average(new double[0]));
     }
 
     @Test
-    public void testAverageInt() {
-        int[] numbers = {2, 4, 10};
-        Assertions.assertEquals(5, Average.average(numbers));
+    void testAverageIntThrowsExceptionOnNullOrEmpty() {
+        assertThrows(IllegalArgumentException.class, () -> Average.average((int[]) null));
+        assertThrows(IllegalArgumentException.class, () -> Average.average(new int[0]));
+    }
+
+    private static Stream<Arguments> provideDoubleArrays() {
+        return Stream.of(Arguments.of(new double[] {3d, 6d, 9d, 12d, 15d, 18d, 21d}, 12d), Arguments.of(new double[] {5d, 10d, 15d, 20d, 25d, 30d, 35d}, 20d), Arguments.of(new double[] {1d, 2d, 3d, 4d, 5d, 6d, 7d, 8d}, 4.5d), Arguments.of(new double[] {0d, 0d, 0d}, 0d),
+            Arguments.of(new double[] {-1d, -2d, -3d}, -2d), Arguments.of(new double[] {1e-10, 1e-10, 1e-10}, 1e-10));
+    }
+
+    private static Stream<Arguments> provideIntArrays() {
+        return Stream.of(Arguments.of(new int[] {2, 4, 10}, 5L), Arguments.of(new int[] {0, 0, 0}, 0L), Arguments.of(new int[] {-1, -2, -3}, -2L), Arguments.of(new int[] {1, 1, 1, 1, 1}, 1L));
     }
 }

From 440b6f5edf86ae8fbf15ff28990f4b62ae46be9c Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Thu, 17 Jul 2025 18:29:45 +0300
Subject: [PATCH 0876/1338] testing: improve tests coverage `AbsoluteValueTest`
 (#6385)

testing: improve tests coverage AbsoluteValueTest
---
 .../maths/AbsoluteValueTest.java              | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/src/test/java/com/thealgorithms/maths/AbsoluteValueTest.java b/src/test/java/com/thealgorithms/maths/AbsoluteValueTest.java
index f87652253641..907d5cb45ef9 100644
--- a/src/test/java/com/thealgorithms/maths/AbsoluteValueTest.java
+++ b/src/test/java/com/thealgorithms/maths/AbsoluteValueTest.java
@@ -12,4 +12,28 @@ public class AbsoluteValueTest {
     void testGetAbsValue() {
         Stream.generate(() -> ThreadLocalRandom.current().nextInt()).limit(1000).forEach(number -> assertEquals(Math.abs(number), AbsoluteValue.getAbsValue(number)));
     }
+
+    @Test
+    void testZero() {
+        assertEquals(0, AbsoluteValue.getAbsValue(0));
+    }
+
+    @Test
+    void testPositiveNumbers() {
+        assertEquals(5, AbsoluteValue.getAbsValue(5));
+        assertEquals(123456, AbsoluteValue.getAbsValue(123456));
+        assertEquals(Integer.MAX_VALUE, AbsoluteValue.getAbsValue(Integer.MAX_VALUE));
+    }
+
+    @Test
+    void testNegativeNumbers() {
+        assertEquals(5, AbsoluteValue.getAbsValue(-5));
+        assertEquals(123456, AbsoluteValue.getAbsValue(-123456));
+        assertEquals(Integer.MAX_VALUE, AbsoluteValue.getAbsValue(-Integer.MAX_VALUE));
+    }
+
+    @Test
+    void testMinIntEdgeCase() {
+        assertEquals(Integer.MIN_VALUE, AbsoluteValue.getAbsValue(Integer.MIN_VALUE));
+    }
 }

From a796f6dc413003b14163787883c0398e0af9e0ac Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Thu, 17 Jul 2025 18:32:48 +0300
Subject: [PATCH 0877/1338] testing: added unit tests for the
 `BinaryPow.binPow` (#6386)

testing: added unit tests for the BinaryPow.binPow

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../thealgorithms/maths/BinaryPowTest.java    | 30 +++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/src/test/java/com/thealgorithms/maths/BinaryPowTest.java b/src/test/java/com/thealgorithms/maths/BinaryPowTest.java
index f9b019e8fad4..632dfbd1d65e 100644
--- a/src/test/java/com/thealgorithms/maths/BinaryPowTest.java
+++ b/src/test/java/com/thealgorithms/maths/BinaryPowTest.java
@@ -13,4 +13,34 @@ void testBinPow() {
         assertEquals(729, BinaryPow.binPow(9, 3));
         assertEquals(262144, BinaryPow.binPow(8, 6));
     }
+
+    @Test
+    void testZeroExponent() {
+        assertEquals(1, BinaryPow.binPow(2, 0));
+        assertEquals(1, BinaryPow.binPow(100, 0));
+        assertEquals(1, BinaryPow.binPow(-5, 0));
+    }
+
+    @Test
+    void testZeroBase() {
+        assertEquals(0, BinaryPow.binPow(0, 5));
+        assertEquals(1, BinaryPow.binPow(0, 0));
+    }
+
+    @Test
+    void testOneBase() {
+        assertEquals(1, BinaryPow.binPow(1, 100));
+        assertEquals(1, BinaryPow.binPow(1, 0));
+    }
+
+    @Test
+    void testNegativeBase() {
+        assertEquals(-8, BinaryPow.binPow(-2, 3));
+        assertEquals(16, BinaryPow.binPow(-2, 4));
+    }
+
+    @Test
+    void testLargeExponent() {
+        assertEquals(1073741824, BinaryPow.binPow(2, 30));
+    }
 }

From 054002adb20c5c37907970543b4c3e6d390e6fbf Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Thu, 17 Jul 2025 18:37:46 +0300
Subject: [PATCH 0878/1338] testing: added unit tests for the
 `MinStackUsingTwoStacks` (#6387)

* testing: added unit tests for the MinStackUsingTwoStacks

* checkstyle: fix import order

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../stacks/MinStackUsingTwoStacksTest.java    | 88 +++++++++++++++++--
 1 file changed, 81 insertions(+), 7 deletions(-)

diff --git a/src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java b/src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java
index e5deb17e9a8f..36bdde49b235 100644
--- a/src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java
+++ b/src/test/java/com/thealgorithms/stacks/MinStackUsingTwoStacksTest.java
@@ -1,38 +1,112 @@
 package com.thealgorithms.stacks;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.util.EmptyStackException;
 import org.junit.jupiter.api.Test;
 
 public class MinStackUsingTwoStacksTest {
 
     @Test
-    public void testMinStackOperations() {
+    public void testBasicOperations() {
         MinStackUsingTwoStacks minStack = new MinStackUsingTwoStacks();
         minStack.push(3);
         minStack.push(5);
-        assertEquals(3, minStack.getMin());
+        assertEquals(3, minStack.getMin(), "Min should be 3");
 
         minStack.push(2);
         minStack.push(1);
-        assertEquals(1, minStack.getMin());
+        assertEquals(1, minStack.getMin(), "Min should be 1");
 
         minStack.pop();
-        assertEquals(2, minStack.getMin());
+        assertEquals(2, minStack.getMin(), "Min should be 2 after popping 1");
+
+        assertEquals(2, minStack.top(), "Top should be 2");
+    }
+
+    @Test
+    public void testPushDuplicateMins() {
+        MinStackUsingTwoStacks minStack = new MinStackUsingTwoStacks();
+        minStack.push(2);
+        minStack.push(2);
+        minStack.push(1);
+        minStack.push(1);
+        assertEquals(1, minStack.getMin(), "Min should be 1");
+
+        minStack.pop();
+        assertEquals(1, minStack.getMin(), "Min should still be 1 after popping one 1");
+
+        minStack.pop();
+        assertEquals(2, minStack.getMin(), "Min should be 2 after popping both 1s");
+
+        minStack.pop();
+        assertEquals(2, minStack.getMin(), "Min should still be 2 after popping one 2");
+
+        minStack.pop();
+        // Now stack is empty, expect exception on getMin
+        assertThrows(EmptyStackException.class, minStack::getMin);
     }
 
     @Test
-    public void testMinStackOperations2() {
+    public void testPopOnEmptyStack() {
         MinStackUsingTwoStacks minStack = new MinStackUsingTwoStacks();
+        assertThrows(EmptyStackException.class, minStack::pop);
+    }
+
+    @Test
+    public void testTopOnEmptyStack() {
+        MinStackUsingTwoStacks minStack = new MinStackUsingTwoStacks();
+        assertThrows(EmptyStackException.class, minStack::top);
+    }
+
+    @Test
+    public void testGetMinOnEmptyStack() {
+        MinStackUsingTwoStacks minStack = new MinStackUsingTwoStacks();
+        assertThrows(EmptyStackException.class, minStack::getMin);
+    }
+
+    @Test
+    public void testSingleElementStack() {
+        MinStackUsingTwoStacks minStack = new MinStackUsingTwoStacks();
+        minStack.push(10);
+        assertEquals(10, minStack.getMin());
+        assertEquals(10, minStack.top());
+
+        minStack.pop();
+        assertThrows(EmptyStackException.class, minStack::getMin);
+    }
+
+    @Test
+    public void testIncreasingSequence() {
+        MinStackUsingTwoStacks minStack = new MinStackUsingTwoStacks();
+        minStack.push(1);
+        minStack.push(2);
         minStack.push(3);
-        minStack.push(5);
-        assertEquals(3, minStack.getMin());
+        minStack.push(4);
+
+        assertEquals(1, minStack.getMin());
+        assertEquals(4, minStack.top());
+
+        minStack.pop();
+        minStack.pop();
+        assertEquals(1, minStack.getMin());
+        assertEquals(2, minStack.top());
+    }
 
+    @Test
+    public void testDecreasingSequence() {
+        MinStackUsingTwoStacks minStack = new MinStackUsingTwoStacks();
+        minStack.push(4);
+        minStack.push(3);
         minStack.push(2);
         minStack.push(1);
+
         assertEquals(1, minStack.getMin());
+        assertEquals(1, minStack.top());
 
         minStack.pop();
         assertEquals(2, minStack.getMin());
+        assertEquals(2, minStack.top());
     }
 }

From 7f6e677b071df752844a931bf9f732b174786b59 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Thu, 17 Jul 2025 23:00:41 +0300
Subject: [PATCH 0879/1338] testing: improve test coverage
 `SortedLinkedListTest` (#6388)

* testing: improve test coverage SortedLinkedListTest

* checkstyle: fix comments formatting

* checkstyle: fix formatting
---
 .../lists/SortedLinkedListTest.java           | 77 +++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java
index 82e0853da374..71f932465eef 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java
@@ -128,4 +128,81 @@ public void testIsEmptyAfterDeletion() {
         list.delete(10);
         assertTrue(list.isEmpty());
     }
+
+    @Test
+    public void testInsertNegativeNumbers() {
+        list.insert(-10);
+        list.insert(-5);
+        list.insert(-20);
+        assertEquals("[-20, -10, -5]", list.toString());
+    }
+
+    @Test
+    public void testInsertMixedPositiveAndNegativeNumbers() {
+        list.insert(0);
+        list.insert(-1);
+        list.insert(1);
+        assertEquals("[-1, 0, 1]", list.toString());
+    }
+
+    @Test
+    public void testMultipleDeletesUntilEmpty() {
+        list.insert(2);
+        list.insert(4);
+        list.insert(6);
+        assertTrue(list.delete(4));
+        assertTrue(list.delete(2));
+        assertTrue(list.delete(6));
+        assertTrue(list.isEmpty());
+        assertEquals("[]", list.toString());
+    }
+
+    @Test
+    public void testDeleteDuplicateValuesOnlyDeletesOneInstance() {
+        list.insert(5);
+        list.insert(5);
+        list.insert(5);
+        assertTrue(list.delete(5));
+        assertEquals("[5, 5]", list.toString());
+        assertTrue(list.delete(5));
+        assertEquals("[5]", list.toString());
+        assertTrue(list.delete(5));
+        assertEquals("[]", list.toString());
+    }
+
+    @Test
+    public void testSearchOnListWithDuplicates() {
+        list.insert(7);
+        list.insert(7);
+        list.insert(7);
+        assertTrue(list.search(7));
+        assertFalse(list.search(10));
+    }
+
+    @Test
+    public void testToStringOnEmptyList() {
+        assertEquals("[]", list.toString());
+    }
+
+    @Test
+    public void testDeleteAllDuplicates() {
+        list.insert(4);
+        list.insert(4);
+        list.insert(4);
+        assertTrue(list.delete(4));
+        assertTrue(list.delete(4));
+        assertTrue(list.delete(4));
+        assertFalse(list.delete(4)); // nothing left to delete
+        assertEquals("[]", list.toString());
+    }
+
+    @Test
+    public void testInsertAfterDeletion() {
+        list.insert(1);
+        list.insert(3);
+        list.insert(5);
+        assertTrue(list.delete(3));
+        list.insert(2);
+        assertEquals("[1, 2, 5]", list.toString());
+    }
 }

From 2f2a32b8c2c2b2e602f2744aa48cc33eaa3f692f Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Thu, 17 Jul 2025 23:03:24 +0300
Subject: [PATCH 0880/1338] testing: improve test coverage `ParityCheckTest`
 (#6389)

testing: improve test coverage ParityCheckTest

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../bitmanipulation/ParityCheckTest.java      | 26 ++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java b/src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java
index 90147a61207b..1654c8ddfc1e 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/ParityCheckTest.java
@@ -6,10 +6,30 @@
 import org.junit.jupiter.api.Test;
 
 public class ParityCheckTest {
+    @Test
+    public void testIsEvenParity() {
+        assertTrue(ParityCheck.checkParity(0)); // 0 -> 0 ones
+        assertTrue(ParityCheck.checkParity(3)); // 11 -> 2 ones
+        assertTrue(ParityCheck.checkParity(5)); // 101 -> 2 ones
+        assertTrue(ParityCheck.checkParity(10)); // 1010 -> 2 ones
+        assertTrue(ParityCheck.checkParity(15)); // 1111 -> 4 ones
+        assertTrue(ParityCheck.checkParity(1023)); // 10 ones
+    }
+
     @Test
     public void testIsOddParity() {
-        assertTrue(ParityCheck.checkParity(5)); // 101 has 2 ones (even parity)
-        assertFalse(ParityCheck.checkParity(7)); // 111 has 3 ones (odd parity)
-        assertFalse(ParityCheck.checkParity(8)); // 1000 has 1 one (odd parity)
+        assertFalse(ParityCheck.checkParity(1)); // 1 -> 1 one
+        assertFalse(ParityCheck.checkParity(2)); // 10 -> 1 one
+        assertFalse(ParityCheck.checkParity(7)); // 111 -> 3 ones
+        assertFalse(ParityCheck.checkParity(8)); // 1000 -> 1 one
+        assertFalse(ParityCheck.checkParity(11)); // 1011 -> 3 ones
+        assertFalse(ParityCheck.checkParity(31)); // 11111 -> 5 ones
+    }
+
+    @Test
+    public void testLargeNumbers() {
+        assertTrue(ParityCheck.checkParity(0b10101010)); // 4 ones
+        assertFalse(ParityCheck.checkParity(0b100000000)); // 1 one
+        assertTrue(ParityCheck.checkParity(0xAAAAAAAA)); // Alternating bits, 16 ones
     }
 }

From d0d4b3c8fb432f50b03d55d2c62ba09c2f950790 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Fri, 18 Jul 2025 08:51:11 +0300
Subject: [PATCH 0881/1338] testing: additional testcases for
 `CountSinglyLinkedListRecursionTest` (#6392)

testing: additional testcases for CountSinglyLinkedListRecursionTest

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../CountSinglyLinkedListRecursionTest.java   | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java b/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java
index 1a3efe8a5572..1d814d0c2f9f 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java
@@ -46,4 +46,39 @@ public void testCountWithDuplicateElements() {
         list.insert(3);
         assertEquals(5, list.count(), "Count of a list with duplicate elements should match total node count.");
     }
+
+    @Test
+    public void testCountAfterClearingList() {
+        for (int i = 1; i <= 4; i++) {
+            list.insert(i);
+        }
+        list.clear(); // assuming you have a clear method; if not, skip this
+        assertEquals(0, list.count(), "Count after clearing the list should be 0.");
+    }
+
+    @Test
+    public void testCountOnVeryLargeList() {
+        int n = 1000;
+        for (int i = 0; i < n; i++) {
+            list.insert(i);
+        }
+        assertEquals(n, list.count(), "Count should correctly return for large list sizes.");
+    }
+
+    @Test
+    public void testCountOnListWithNegativeNumbers() {
+        list.insert(-1);
+        list.insert(-5);
+        list.insert(-10);
+        assertEquals(3, list.count(), "Count should correctly handle negative values.");
+    }
+
+    @Test
+    public void testCountIsConsistentWithoutModification() {
+        list.insert(1);
+        list.insert(2);
+        int firstCount = list.count();
+        int secondCount = list.count();
+        assertEquals(firstCount, secondCount, "Repeated count calls should return consistent values.");
+    }
 }

From 44c572b36bd8d2d80fcd85fd296ea9fb5221306e Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 18 Jul 2025 13:58:17 +0300
Subject: [PATCH 0882/1338] chore(deps): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.6.11 to 7.6.12 (#6406)

chore(deps): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.6.11 to 7.6.12.
- [Commits](https://github.com/mebigfatguy/fb-contrib/commits/v7.6.12)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.6.12
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index f5f1e0be12f7..f18462bec8fb 100644
--- a/pom.xml
+++ b/pom.xml
@@ -128,7 +128,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.11</version>
+                            <version>7.6.12</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

From fc477ee8da73656ae5ab5c4d481466951025580a Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Fri, 18 Jul 2025 22:29:16 +0300
Subject: [PATCH 0883/1338] testing: improving test coverage
 `CountingInversionsTest` (#6393)

testing: improving test coverage CountingInversionsTest

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../CountingInversionsTest.java               | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java b/src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java
index d12614d6fd06..f8356a87eb31 100644
--- a/src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java
+++ b/src/test/java/com/thealgorithms/divideandconquer/CountingInversionsTest.java
@@ -29,4 +29,35 @@ public void testAllInversions() {
         int[] arr = {5, 4, 3, 2, 1};
         assertEquals(10, CountingInversions.countInversions(arr));
     }
+
+    @Test
+    public void testEmptyArray() {
+        int[] arr = {};
+        assertEquals(0, CountingInversions.countInversions(arr));
+    }
+
+    @Test
+    public void testArrayWithDuplicates() {
+        int[] arr = {1, 3, 2, 3, 1};
+        // Inversions: (3,2), (3,1), (3,1), (2,1)
+        assertEquals(4, CountingInversions.countInversions(arr));
+    }
+
+    @Test
+    public void testLargeArray() {
+        int n = 1000;
+        int[] arr = new int[n];
+        for (int i = 0; i < n; i++) {
+            arr[i] = n - i; // descending order -> max inversions = n*(n-1)/2
+        }
+        int expected = n * (n - 1) / 2;
+        assertEquals(expected, CountingInversions.countInversions(arr));
+    }
+
+    @Test
+    public void testArrayWithAllSameElements() {
+        int[] arr = {7, 7, 7, 7};
+        // No inversions since all elements are equal
+        assertEquals(0, CountingInversions.countInversions(arr));
+    }
 }

From d6a871e683e33a6045c3d11181b3be7c8772d0dc Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Fri, 18 Jul 2025 23:55:37 +0300
Subject: [PATCH 0884/1338] testing: improve test coverage
 `RangeInSortedArrayTest` (#6395)

* testing: improve test coverage RangeInSortedArrayTest

* style: fix formatting checkstyle

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../misc/RangeInSortedArrayTest.java          | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java b/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java
index 7630d3e78dc7..543c66130449 100644
--- a/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java
+++ b/src/test/java/com/thealgorithms/misc/RangeInSortedArrayTest.java
@@ -32,4 +32,26 @@ private static Stream<Arguments> provideGetCountLessThanTestCases() {
         return Stream.of(Arguments.of(new int[] {1, 2, 3, 3, 4, 5}, 3, 4, "Count of elements less than existing key"), Arguments.of(new int[] {1, 2, 3, 3, 4, 5}, 4, 5, "Count of elements less than non-existing key"), Arguments.of(new int[] {1, 2, 2, 3}, 5, 4, "Count with all smaller elements"),
             Arguments.of(new int[] {2, 3, 4, 5}, 1, 0, "Count with no smaller elements"), Arguments.of(new int[] {}, 1, 0, "Count in empty array"));
     }
+
+    @ParameterizedTest(name = "Edge case {index}: {3}")
+    @MethodSource("provideEdgeCasesForSortedRange")
+    void testSortedRangeEdgeCases(int[] nums, int key, int[] expectedRange, String description) {
+        assertArrayEquals(expectedRange, RangeInSortedArray.sortedRange(nums, key), description);
+    }
+
+    private static Stream<Arguments> provideEdgeCasesForSortedRange() {
+        return Stream.of(Arguments.of(new int[] {5, 5, 5, 5, 5}, 5, new int[] {0, 4}, "All elements same as key"), Arguments.of(new int[] {1, 2, 3, 4, 5}, 1, new int[] {0, 0}, "Key is first element"), Arguments.of(new int[] {1, 2, 3, 4, 5}, 5, new int[] {4, 4}, "Key is last element"),
+            Arguments.of(new int[] {1, 2, 3, 4, 5}, 0, new int[] {-1, -1}, "Key less than all elements"), Arguments.of(new int[] {1, 2, 3, 4, 5}, 6, new int[] {-1, -1}, "Key greater than all elements"),
+            Arguments.of(new int[] {1, 2, 2, 2, 3, 3, 3, 4}, 3, new int[] {4, 6}, "Multiple occurrences spread"), Arguments.of(new int[] {2}, 2, new int[] {0, 0}, "Single element array key exists"), Arguments.of(new int[] {2}, 3, new int[] {-1, -1}, "Single element array key missing"));
+    }
+
+    @ParameterizedTest(name = "Edge case {index}: {3}")
+    @MethodSource("provideEdgeCasesForGetCountLessThan")
+    void testGetCountLessThanEdgeCases(int[] nums, int key, int expectedCount, String description) {
+        assertEquals(expectedCount, RangeInSortedArray.getCountLessThan(nums, key), description);
+    }
+
+    private static Stream<Arguments> provideEdgeCasesForGetCountLessThan() {
+        return Stream.of(Arguments.of(new int[] {1, 2, 3, 4, 5}, 0, 0, "Key less than all elements"), Arguments.of(new int[] {1, 2, 3, 4, 5}, 6, 5, "Key greater than all elements"), Arguments.of(new int[] {1}, 0, 0, "Single element greater than key"));
+    }
 }

From 5c6d3c3443d33d968724e5cb0e58588b8ebbc4a3 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Fri, 18 Jul 2025 23:01:50 +0200
Subject: [PATCH 0885/1338] Update DIRECTORY.md (#6414)

Co-authored-by: DenizAltunkapan <DenizAltunkapan@users.noreply.github.com>
---
 DIRECTORY.md | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 9697dbc09869..b399044a0481 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1,5 +1,7 @@
 # Project Structure
 
+## src
+
 - 📁 **main**
   - 📁 **java**
     - 📁 **com**
@@ -165,12 +167,10 @@
             - 📄 [Kruskal](src/main/java/com/thealgorithms/datastructures/graphs/Kruskal.java)
             - 📄 [MatrixGraphs](src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java)
             - 📄 [PrimMST](src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java)
-            - 📄 [README](src/main/java/com/thealgorithms/datastructures/graphs/README.md)
             - 📄 [TarjansAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java)
             - 📄 [UndirectedAdjacencyListGraph](src/main/java/com/thealgorithms/datastructures/graphs/UndirectedAdjacencyListGraph.java)
             - 📄 [WelshPowell](src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java)
           - 📁 **hashmap**
-            - 📄 [Readme](src/main/java/com/thealgorithms/datastructures/hashmap/Readme.md)
             - 📁 **hashing**
               - 📄 [GenericHashMapUsingArray](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java)
               - 📄 [GenericHashMapUsingArrayList](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java)
@@ -194,7 +194,6 @@
             - 📄 [MergeKSortedArrays](src/main/java/com/thealgorithms/datastructures/heaps/MergeKSortedArrays.java)
             - 📄 [MinHeap](src/main/java/com/thealgorithms/datastructures/heaps/MinHeap.java)
             - 📄 [MinPriorityQueue](src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java)
-            - 📄 [Readme](src/main/java/com/thealgorithms/datastructures/heaps/Readme.md)
           - 📁 **lists**
             - 📄 [CircleLinkedList](src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java)
             - 📄 [CountSinglyLinkedListRecursion](src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java)
@@ -205,7 +204,6 @@
             - 📄 [MergeSortedArrayList](src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java)
             - 📄 [MergeSortedSinglyLinkedList](src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java)
             - 📄 [QuickSortLinkedList](src/main/java/com/thealgorithms/datastructures/lists/QuickSortLinkedList.java)
-            - 📄 [README](src/main/java/com/thealgorithms/datastructures/lists/README.md)
             - 📄 [RandomNode](src/main/java/com/thealgorithms/datastructures/lists/RandomNode.java)
             - 📄 [ReverseKGroup](src/main/java/com/thealgorithms/datastructures/lists/ReverseKGroup.java)
             - 📄 [RotateSinglyLinkedLists](src/main/java/com/thealgorithms/datastructures/lists/RotateSinglyLinkedLists.java)
@@ -222,12 +220,10 @@
             - 📄 [PriorityQueues](src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java)
             - 📄 [Queue](src/main/java/com/thealgorithms/datastructures/queues/Queue.java)
             - 📄 [QueueByTwoStacks](src/main/java/com/thealgorithms/datastructures/queues/QueueByTwoStacks.java)
-            - 📄 [README](src/main/java/com/thealgorithms/datastructures/queues/README.md)
             - 📄 [SlidingWindowMaximum](src/main/java/com/thealgorithms/datastructures/queues/SlidingWindowMaximum.java)
             - 📄 [TokenBucket](src/main/java/com/thealgorithms/datastructures/queues/TokenBucket.java)
           - 📁 **stacks**
             - 📄 [NodeStack](src/main/java/com/thealgorithms/datastructures/stacks/NodeStack.java)
-            - 📄 [README](src/main/java/com/thealgorithms/datastructures/stacks/README.md)
             - 📄 [ReverseStack](src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java)
             - 📄 [Stack](src/main/java/com/thealgorithms/datastructures/stacks/Stack.java)
             - 📄 [StackArray](src/main/java/com/thealgorithms/datastructures/stacks/StackArray.java)
@@ -259,7 +255,6 @@
             - 📄 [PreOrderTraversal](src/main/java/com/thealgorithms/datastructures/trees/PreOrderTraversal.java)
             - 📄 [PrintTopViewofTree](src/main/java/com/thealgorithms/datastructures/trees/PrintTopViewofTree.java)
             - 📄 [QuadTree](src/main/java/com/thealgorithms/datastructures/trees/QuadTree.java)
-            - 📄 [README](src/main/java/com/thealgorithms/datastructures/trees/README.md)
             - 📄 [RedBlackBST](src/main/java/com/thealgorithms/datastructures/trees/RedBlackBST.java)
             - 📄 [SameTreesCheck](src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java)
             - 📄 [SegmentTree](src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java)
@@ -749,7 +744,6 @@
           - 📄 [ValidParentheses](src/main/java/com/thealgorithms/strings/ValidParentheses.java)
           - 📄 [WordLadder](src/main/java/com/thealgorithms/strings/WordLadder.java)
           - 📁 **zigZagPattern**
-            - 📄 [README](src/main/java/com/thealgorithms/strings/zigZagPattern/README.md)
             - 📄 [ZigZagPattern](src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java)
         - 📁 **tree**
           - 📄 [HeavyLightDecomposition](src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java)
@@ -1416,4 +1410,4 @@
           - 📁 **zigZagPattern**
             - 📄 [ZigZagPatternTest](src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java)
         - 📁 **tree**
-          - 📄 [HeavyLightDecompositionTest](src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java)
\ No newline at end of file
+          - 📄 [HeavyLightDecompositionTest](src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java)

From 76aea4254c732fa631acb0a9a47fda38389805b3 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sat, 19 Jul 2025 10:57:58 +0300
Subject: [PATCH 0886/1338] testing: improving test coverage
 `DisjointSetUnionTest` (#6394)

* testing: improving test coverage DisjointSetUnionTest

* style: remove redundant comment

* testing: removing unused variable

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../DisjointSetUnionTest.java                 | 102 +++++++++++++++---
 1 file changed, 88 insertions(+), 14 deletions(-)

diff --git a/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java b/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java
index a10a99d40496..14dceb53c40d 100644
--- a/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java
@@ -1,8 +1,9 @@
 package com.thealgorithms.datastructures.disjointsetunion;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 public class DisjointSetUnionTest {
@@ -12,7 +13,7 @@ public void testMakeSet() {
         DisjointSetUnion<Integer> dsu = new DisjointSetUnion<>();
         Node<Integer> node = dsu.makeSet(1);
         assertNotNull(node);
-        Assertions.assertEquals(node, node.parent);
+        assertEquals(node, node.parent);
     }
 
     @Test
@@ -33,19 +34,92 @@ public void testUnionFindSet() {
         Node<Integer> root3 = dsu.findSet(node3);
         Node<Integer> root4 = dsu.findSet(node4);
 
-        Assertions.assertEquals(node1, node1.parent);
-        Assertions.assertEquals(node1, node2.parent);
-        Assertions.assertEquals(node1, node3.parent);
-        Assertions.assertEquals(node1, node4.parent);
+        assertEquals(node1, node1.parent);
+        assertEquals(node1, node2.parent);
+        assertEquals(node1, node3.parent);
+        assertEquals(node1, node4.parent);
 
-        Assertions.assertEquals(node1, root1);
-        Assertions.assertEquals(node1, root2);
-        Assertions.assertEquals(node1, root3);
-        Assertions.assertEquals(node1, root4);
+        assertEquals(node1, root1);
+        assertEquals(node1, root2);
+        assertEquals(node1, root3);
+        assertEquals(node1, root4);
 
-        Assertions.assertEquals(1, node1.rank);
-        Assertions.assertEquals(0, node2.rank);
-        Assertions.assertEquals(0, node3.rank);
-        Assertions.assertEquals(0, node4.rank);
+        assertEquals(1, node1.rank);
+        assertEquals(0, node2.rank);
+        assertEquals(0, node3.rank);
+        assertEquals(0, node4.rank);
+    }
+
+    @Test
+    public void testFindSetOnSingleNode() {
+        DisjointSetUnion<String> dsu = new DisjointSetUnion<>();
+        Node<String> node = dsu.makeSet("A");
+        assertEquals(node, dsu.findSet(node));
+    }
+
+    @Test
+    public void testUnionAlreadyConnectedNodes() {
+        DisjointSetUnion<Integer> dsu = new DisjointSetUnion<>();
+        Node<Integer> node1 = dsu.makeSet(1);
+        Node<Integer> node2 = dsu.makeSet(2);
+        Node<Integer> node3 = dsu.makeSet(3);
+
+        dsu.unionSets(node1, node2);
+        dsu.unionSets(node2, node3);
+
+        // Union nodes that are already connected
+        dsu.unionSets(node1, node3);
+
+        // All should have the same root
+        Node<Integer> root = dsu.findSet(node1);
+        assertEquals(root, dsu.findSet(node2));
+        assertEquals(root, dsu.findSet(node3));
+    }
+
+    @Test
+    public void testRankIncrease() {
+        DisjointSetUnion<Integer> dsu = new DisjointSetUnion<>();
+        Node<Integer> node1 = dsu.makeSet(1);
+        Node<Integer> node2 = dsu.makeSet(2);
+        Node<Integer> node3 = dsu.makeSet(3);
+        Node<Integer> node4 = dsu.makeSet(4);
+
+        dsu.unionSets(node1, node2); // rank of node1 should increase
+        dsu.unionSets(node3, node4); // rank of node3 should increase
+        dsu.unionSets(node1, node3); // union two trees of same rank -> rank increases
+
+        assertEquals(2, dsu.findSet(node1).rank);
+    }
+
+    @Test
+    public void testMultipleMakeSets() {
+        DisjointSetUnion<Integer> dsu = new DisjointSetUnion<>();
+        Node<Integer> node1 = dsu.makeSet(1);
+        Node<Integer> node2 = dsu.makeSet(2);
+        Node<Integer> node3 = dsu.makeSet(3);
+
+        assertNotEquals(node1, node2);
+        assertNotEquals(node2, node3);
+        assertNotEquals(node1, node3);
+
+        assertEquals(node1, node1.parent);
+        assertEquals(node2, node2.parent);
+        assertEquals(node3, node3.parent);
+    }
+
+    @Test
+    public void testPathCompression() {
+        DisjointSetUnion<Integer> dsu = new DisjointSetUnion<>();
+        Node<Integer> node1 = dsu.makeSet(1);
+        Node<Integer> node2 = dsu.makeSet(2);
+        Node<Integer> node3 = dsu.makeSet(3);
+
+        dsu.unionSets(node1, node2);
+        dsu.unionSets(node2, node3);
+
+        // After findSet, path compression should update parent to root directly
+        Node<Integer> root = dsu.findSet(node3);
+        assertEquals(root, node1);
+        assertEquals(node1, node3.parent);
     }
 }

From d14e8a60e8b0c7e133d48c1161df7604e2aa0894 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sat, 19 Jul 2025 11:00:49 +0300
Subject: [PATCH 0887/1338] testing: improve test coverage
 `DuplicateBracketsTest` (#6396)

* testing: improve test coverage DuplicateBracketsTest

* style: fix formatting checkstyle

* style: fix formatting checkstyle

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../stacks/DuplicateBracketsTest.java         | 30 +++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java b/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java
index e2cc6acb8112..bc7b3266d98e 100644
--- a/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java
+++ b/src/test/java/com/thealgorithms/stacks/DuplicateBracketsTest.java
@@ -4,20 +4,23 @@
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class DuplicateBracketsTest {
 
     @ParameterizedTest
-    @CsvSource({"'((a + b) + (c + d))'", "'(a + b)'", "'a + b'", "'('", "''"})
+    @CsvSource({"'((a + b) + (c + d))'", "'(a + b)'", "'a + b'", "'('", "''", "'a + (b * c) - d'", "'(x + y) * (z)'", "'(a + (b - c))'"})
     void testInputReturnsFalse(String input) {
         assertFalse(DuplicateBrackets.check(input));
     }
 
     @ParameterizedTest
-    @CsvSource({"'(a + b) + ((c + d))'", "'((a + b))'", "'((((a + b)))))'"})
+    @CsvSource({"'(a + b) + ((c + d))'", "'((a + b))'", "'((((a + b)))))'", "'((x))'", "'((a + (b)))'", "'(a + ((b)))'", "'(((a)))'", "'(((())))'"})
     void testInputReturnsTrue(String input) {
         assertTrue(DuplicateBrackets.check(input));
     }
@@ -26,4 +29,27 @@ void testInputReturnsTrue(String input) {
     void testInvalidInput() {
         assertThrows(IllegalArgumentException.class, () -> DuplicateBrackets.check(null));
     }
+
+    @ParameterizedTest(name = "Should be true: \"{0}\"")
+    @MethodSource("provideInputsThatShouldReturnTrue")
+    void testDuplicateBracketsTrueCases(String input) {
+        assertTrue(DuplicateBrackets.check(input));
+    }
+
+    static Stream<Arguments> provideInputsThatShouldReturnTrue() {
+        return Stream.of(Arguments.of("()"), Arguments.of("(( ))"));
+    }
+
+    @ParameterizedTest(name = "Should be false: \"{0}\"")
+    @MethodSource("provideInputsThatShouldReturnFalse")
+    void testDuplicateBracketsFalseCases(String input) {
+        assertFalse(DuplicateBrackets.check(input));
+    }
+
+    static Stream<Arguments> provideInputsThatShouldReturnFalse() {
+        return Stream.of(Arguments.of("( )"), // whitespace inside brackets
+            Arguments.of("abc + def"), // no brackets
+            Arguments.of("(a + (b * c)) - (d / e)") // complex, but no duplicates
+        );
+    }
 }

From 334543f54c0e64a4fcdbfc162830842c9118c1cf Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sat, 19 Jul 2025 17:04:10 +0300
Subject: [PATCH 0888/1338] testing: improve test coverage `PriorityQueuesTest`
 (#6397)

testing: improve test coverage PriorityQueuesTest

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../queues/PriorityQueuesTest.java            | 56 +++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java b/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java
index 1a3b5aadebb2..e97fe091c556 100644
--- a/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java
@@ -55,4 +55,60 @@ void testPQExtra() {
         Assertions.assertEquals(myQueue.peek(), 2);
         Assertions.assertEquals(myQueue.getSize(), 1);
     }
+
+    @Test
+    void testInsertUntilFull() {
+        PriorityQueue pq = new PriorityQueue(3);
+        pq.insert(1);
+        pq.insert(4);
+        pq.insert(2);
+        Assertions.assertTrue(pq.isFull());
+        Assertions.assertEquals(4, pq.peek());
+    }
+
+    @Test
+    void testRemoveFromEmpty() {
+        PriorityQueue pq = new PriorityQueue(3);
+        Assertions.assertThrows(RuntimeException.class, pq::remove);
+    }
+
+    @Test
+    void testInsertDuplicateValues() {
+        PriorityQueue pq = new PriorityQueue(5);
+        pq.insert(5);
+        pq.insert(5);
+        pq.insert(3);
+        Assertions.assertEquals(5, pq.peek());
+        pq.remove();
+        Assertions.assertEquals(5, pq.peek());
+        pq.remove();
+        Assertions.assertEquals(3, pq.peek());
+    }
+
+    @Test
+    void testSizeAfterInsertAndRemove() {
+        PriorityQueue pq = new PriorityQueue(4);
+        Assertions.assertEquals(0, pq.getSize());
+        pq.insert(2);
+        Assertions.assertEquals(1, pq.getSize());
+        pq.insert(10);
+        Assertions.assertEquals(2, pq.getSize());
+        pq.remove();
+        Assertions.assertEquals(1, pq.getSize());
+        pq.remove();
+        Assertions.assertEquals(0, pq.getSize());
+    }
+
+    @Test
+    void testInsertAndRemoveAll() {
+        PriorityQueue pq = new PriorityQueue(3);
+        pq.insert(8);
+        pq.insert(1);
+        pq.insert(6);
+        Assertions.assertTrue(pq.isFull());
+        pq.remove();
+        pq.remove();
+        pq.remove();
+        Assertions.assertTrue(pq.isEmpty());
+    }
 }

From 0a46b828c2daf173d8dec87561a900568780a683 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sat, 19 Jul 2025 17:07:54 +0300
Subject: [PATCH 0889/1338] testing: Enhance `ValidParenthesesTest` (#6398)

* testing: improve test coverage ValidParenthesesTest

* style: fix formatting for checkstyle

* style: fix formatting for checkstyle

* style: fix import

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../strings/ValidParenthesesTest.java         | 22 +++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
index 23d41b159fe2..411b11e743b8 100644
--- a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
+++ b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
@@ -1,15 +1,33 @@
 package com.thealgorithms.strings;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
 
 public class ValidParenthesesTest {
 
     @ParameterizedTest(name = "Input: \"{0}\" → Expected: {1}")
-    @CsvSource({"'()', true", "'()[]{}', true", "'(]', false", "'{[]}', true", "'([{}])', true", "'([)]', false", "'', true", "'(', false", "')', false"})
-    void testIsValid(String input, boolean expected) {
+    @CsvSource({"'()', true", "'()[]{}', true", "'(]', false", "'{[]}', true", "'([{}])', true", "'([)]', false", "'', true", "'(', false", "')', false", "'{{{{}}}}', true", "'[({})]', true", "'[(])', false", "'[', false", "']', false", "'()()()()', true", "'(()', false", "'())', false",
+        "'{[()()]()}', true"})
+    void
+    testIsValid(String input, boolean expected) {
         assertEquals(expected, ValidParentheses.isValid(input));
     }
+
+    @Test
+    void testNullInputThrows() {
+        IllegalArgumentException ex = assertThrows(IllegalArgumentException.class, () -> ValidParentheses.isValid(null));
+        assertEquals("Input string cannot be null", ex.getMessage());
+    }
+
+    @ParameterizedTest(name = "Input: \"{0}\" → throws IllegalArgumentException")
+    @CsvSource({"'a'", "'()a'", "'[123]'", "'{hello}'", "'( )'", "'\t'", "'\n'", "'@#$%'"})
+    void testInvalidCharactersThrow(String input) {
+        IllegalArgumentException ex = assertThrows(IllegalArgumentException.class, () -> ValidParentheses.isValid(input));
+        assertTrue(ex.getMessage().startsWith("Unexpected character"));
+    }
 }

From c7af421dfa1fd5d0c3aa54890d2f4ece0df59324 Mon Sep 17 00:00:00 2001
From: justakayy <xaaron.kuehnx@gmail.com>
Date: Sun, 20 Jul 2025 09:59:18 +0200
Subject: [PATCH 0890/1338] test: PointTest.java #HSFDPMUW (#6391)

* test: added Tests for Point.java

* style: fixed formatting and comments

* style: formatted with clang-format and renamed variables

* style: fixed imports to not use the '.*' form

---------

Co-authored-by: Aaron <aaron@hochschule.de>
Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../com/thealgorithms/geometry/PointTest.java | 117 ++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/geometry/PointTest.java

diff --git a/src/test/java/com/thealgorithms/geometry/PointTest.java b/src/test/java/com/thealgorithms/geometry/PointTest.java
new file mode 100644
index 000000000000..12901364b458
--- /dev/null
+++ b/src/test/java/com/thealgorithms/geometry/PointTest.java
@@ -0,0 +1,117 @@
+package com.thealgorithms.geometry;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class PointTest {
+
+    @Test
+    void testCompareTo() {
+        Point p1 = new Point(1, 2);
+        Point p2 = new Point(5, -1);
+        Point p3 = new Point(3, 9);
+        Point p4 = new Point(3, 9);
+        assertEquals(1, p1.compareTo(p2));
+        assertEquals(-1, p2.compareTo(p3));
+        assertEquals(0, p3.compareTo(p4));
+    }
+
+    @Test
+    void testToString() {
+        Point p = new Point(-3, 5);
+        assertEquals("(-3, 5)", p.toString());
+    }
+
+    @Test
+    void testPolarOrder() {
+        Point p = new Point(0, 0);
+        assertNotNull(p.polarOrder());
+    }
+
+    @Test
+    void testOrientation() {
+        // setup points
+        Point pA = new Point(0, 0);
+        Point pB = new Point(1, 0);
+        Point pC = new Point(1, 1);
+
+        // test for left curve
+        assertEquals(1, Point.orientation(pA, pB, pC));
+
+        // test for right curve
+        pB = new Point(0, 1);
+        assertEquals(-1, Point.orientation(pA, pB, pC));
+
+        // test for left curve
+        pC = new Point(-1, 1);
+        assertEquals(1, Point.orientation(pA, pB, pC));
+
+        // test for right curve
+        pB = new Point(1, 0);
+        pC = new Point(1, -1);
+        assertEquals(-1, Point.orientation(pA, pB, pC));
+
+        // test for collinearity
+        pB = new Point(1, 1);
+        pC = new Point(2, 2);
+        assertEquals(0, Point.orientation(pA, pB, pC));
+    }
+
+    @Test
+    void testPolarOrderCompare() {
+        Point ref = new Point(0, 0);
+
+        Point pA = new Point(1, 1);
+        Point pB = new Point(1, -1);
+        assertTrue(ref.polarOrder().compare(pA, pB) < 0);
+
+        pA = new Point(3, 0);
+        pB = new Point(2, 0);
+        assertTrue(ref.polarOrder().compare(pA, pB) < 0);
+
+        pA = new Point(0, 1);
+        pB = new Point(-1, 1);
+        assertTrue(ref.polarOrder().compare(pA, pB) < 0);
+
+        pA = new Point(1, 1);
+        pB = new Point(2, 2);
+        assertEquals(0, ref.polarOrder().compare(pA, pB));
+
+        pA = new Point(1, 2);
+        pB = new Point(2, 1);
+        assertTrue(ref.polarOrder().compare(pA, pB) > 0);
+
+        pA = new Point(2, 1);
+        pB = new Point(1, 2);
+        assertTrue(ref.polarOrder().compare(pA, pB) < 0);
+
+        pA = new Point(-1, 0);
+        pB = new Point(-2, 0);
+        assertTrue(ref.polarOrder().compare(pA, pB) < 0);
+
+        pA = new Point(2, 3);
+        pB = new Point(2, 3);
+        assertEquals(0, ref.polarOrder().compare(pA, pB));
+
+        pA = new Point(0, 1);
+        pB = new Point(0, -1);
+        assertTrue(ref.polarOrder().compare(pA, pB) < 0);
+
+        ref = new Point(1, 1);
+
+        pA = new Point(1, 2);
+        pB = new Point(2, 2);
+        assertTrue(ref.polarOrder().compare(pA, pB) > 0);
+
+        pA = new Point(2, 1);
+        pB = new Point(2, 0);
+        assertTrue(ref.polarOrder().compare(pA, pB) < 0);
+
+        pA = new Point(0, 1);
+        pB = new Point(1, 0);
+        assertTrue(ref.polarOrder().compare(pA, pB) < 0);
+    }
+}

From 171fdc9925f3656a58d00ff2e3e4b60c547a0778 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sun, 20 Jul 2025 11:03:23 +0300
Subject: [PATCH 0891/1338] testing: improving `CRCAlgorithmTest` (#6403)

* testing: improving CRCAlgorithmTest

* style: fix formatting

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../others/CRCAlgorithmTest.java              | 71 ++++++++++++++++---
 1 file changed, 62 insertions(+), 9 deletions(-)

diff --git a/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java b/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java
index a581a35bf963..542c256a3e88 100644
--- a/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java
@@ -1,29 +1,82 @@
-
 package com.thealgorithms.others;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
 public class CRCAlgorithmTest {
 
     @Test
-    void test1() {
+    void testNoErrorsWithZeroBER() {
         CRCAlgorithm c = new CRCAlgorithm("10010101010100101010010000001010010101010", 10, 0.0);
-
-        // A bit-error rate of 0.0 should not provide any wrong messages
-        c.changeMess();
+        c.generateRandomMess();
         c.divideMessageWithP(false);
-        assertEquals(c.getWrongMess(), 0);
+        c.changeMess();
+        c.divideMessageWithP(true);
+        assertEquals(0, c.getWrongMess(), "BER=0 should produce no wrong messages");
+        assertEquals(0, c.getWrongMessCaught(), "No errors, so no caught wrong messages");
+        assertEquals(0, c.getWrongMessNotCaught(), "No errors, so no uncaught wrong messages");
+        assertTrue(c.getCorrectMess() > 0, "Should have some correct messages");
     }
 
     @Test
-    void test2() {
+    void testAllErrorsWithBEROne() {
         CRCAlgorithm c = new CRCAlgorithm("10010101010100101010010000001010010101010", 10, 1.0);
+        c.generateRandomMess();
+        c.divideMessageWithP(false);
+        c.changeMess();
+        c.divideMessageWithP(true);
+        assertTrue(c.getWrongMess() > 0, "BER=1 should produce wrong messages");
+        assertEquals(0, c.getCorrectMess(), "BER=1 should produce no correct messages");
+    }
 
-        // A bit error rate of 1.0 should not provide any correct messages
+    @Test
+    void testIntermediateBER() {
+        CRCAlgorithm c = new CRCAlgorithm("1101", 4, 0.5);
+        c.generateRandomMess();
+        for (int i = 0; i < 1000; i++) {
+            c.refactor();
+            c.generateRandomMess();
+            c.divideMessageWithP(false);
+            c.changeMess();
+            c.divideMessageWithP(true);
+        }
+        assertTrue(c.getWrongMess() > 0, "Some wrong messages expected with BER=0.5");
+        assertTrue(c.getWrongMessCaught() >= 0, "Wrong messages caught counter >= 0");
+        assertTrue(c.getWrongMessNotCaught() >= 0, "Wrong messages not caught counter >= 0");
+        assertTrue(c.getCorrectMess() >= 0, "Correct messages counter >= 0");
+        assertEquals(c.getWrongMess(), c.getWrongMessCaught() + c.getWrongMessNotCaught(), "Sum of caught and not caught wrong messages should equal total wrong messages");
+    }
+
+    @Test
+    void testMessageChangedFlag() {
+        CRCAlgorithm c = new CRCAlgorithm("1010", 4, 1.0);
+        c.generateRandomMess();
+        c.divideMessageWithP(false);
+        c.changeMess();
+        assertTrue(c.getWrongMess() > 0, "Message should be marked as changed with BER=1");
+    }
+
+    @Test
+    void testSmallMessageSize() {
+        CRCAlgorithm c = new CRCAlgorithm("11", 2, 0.0);
+        c.generateRandomMess();
+        c.divideMessageWithP(false);
         c.changeMess();
+        c.divideMessageWithP(true);
+        assertEquals(0, c.getWrongMess(), "No errors expected for BER=0 with small message");
+    }
+
+    @Test
+    void testLargeMessageSize() {
+        CRCAlgorithm c = new CRCAlgorithm("1101", 1000, 0.01);
+        c.generateRandomMess();
         c.divideMessageWithP(false);
-        assertEquals(c.getCorrectMess(), 0);
+        c.changeMess();
+        c.divideMessageWithP(true);
+        // Just ensure counters are updated, no exceptions
+        assertTrue(c.getWrongMess() >= 0);
+        assertTrue(c.getCorrectMess() >= 0);
     }
 }

From b45fd2a6560b9e7f2732414547c98caf3c16582b Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Sun, 20 Jul 2025 10:13:12 +0200
Subject: [PATCH 0892/1338] Update DIRECTORY.md (#6419)

Co-authored-by: DenizAltunkapan <DenizAltunkapan@users.noreply.github.com>
---
 DIRECTORY.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b399044a0481..cae5b8067c41 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -1042,6 +1042,7 @@
           - 📄 [GrahamScanTest](src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
           - 📄 [MidpointCircleTest](src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java)
           - 📄 [MidpointEllipseTest](src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java)
+          - 📄 [PointTest](src/test/java/com/thealgorithms/geometry/PointTest.java)
         - 📁 **graph**
           - 📄 [ConstrainedShortestPathTest](src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java)
           - 📄 [StronglyConnectedComponentOptimizedTest](src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)

From 31bf130e9eb14409c6f628f0a64a419fc6564e61 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sun, 20 Jul 2025 11:21:46 +0300
Subject: [PATCH 0893/1338] refactor: improving `Median` (#6404)

refactor: improving Median

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 src/main/java/com/thealgorithms/maths/Median.java     | 5 +++++
 src/test/java/com/thealgorithms/maths/MedianTest.java | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/src/main/java/com/thealgorithms/maths/Median.java b/src/main/java/com/thealgorithms/maths/Median.java
index e4daec8fc11a..fd2aab84e4e9 100644
--- a/src/main/java/com/thealgorithms/maths/Median.java
+++ b/src/main/java/com/thealgorithms/maths/Median.java
@@ -13,8 +13,13 @@ private Median() {
      * Calculate average median
      * @param values sorted numbers to find median of
      * @return median of given {@code values}
+     * @throws IllegalArgumentException If the input array is empty or null.
      */
     public static double median(int[] values) {
+        if (values == null || values.length == 0) {
+            throw new IllegalArgumentException("Values array cannot be empty or null");
+        }
+
         Arrays.sort(values);
         int length = values.length;
         return length % 2 == 0 ? (values[length / 2] + values[length / 2 - 1]) / 2.0 : values[length / 2];
diff --git a/src/test/java/com/thealgorithms/maths/MedianTest.java b/src/test/java/com/thealgorithms/maths/MedianTest.java
index d2b637abd3cb..560feb695792 100644
--- a/src/test/java/com/thealgorithms/maths/MedianTest.java
+++ b/src/test/java/com/thealgorithms/maths/MedianTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.maths;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
@@ -34,4 +35,10 @@ void medianNegativeValues() {
         int[] arr = {-27, -16, -7, -4, -2, -1};
         assertEquals(-5.5, Median.median(arr));
     }
+
+    @Test
+    void medianEmptyArrayThrows() {
+        int[] arr = {};
+        assertThrows(IllegalArgumentException.class, () -> Median.median(arr));
+    }
 }

From 0e9be57ed44e3772dcc5be097b5faeb71a70f1f7 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Mon, 21 Jul 2025 17:55:07 +0200
Subject: [PATCH 0894/1338] testing: improving `PostfixEvaluatorTest` (#6405)

* testing: improving PostfixEvaluatorTest

* testing: redundant cases
---
 .../stacks/PostfixEvaluatorTest.java          | 31 ++++++++++++++-----
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java b/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java
index 882fe644ccd5..682240acd752 100644
--- a/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java
+++ b/src/test/java/com/thealgorithms/stacks/PostfixEvaluatorTest.java
@@ -4,24 +4,41 @@
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.EmptyStackException;
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class PostfixEvaluatorTest {
 
-    @Test
-    public void testValidExpressions() {
-        assertEquals(22, PostfixEvaluator.evaluatePostfix("5 6 + 2 *"));
-        assertEquals(27, PostfixEvaluator.evaluatePostfix("7 2 + 3 *"));
-        assertEquals(3, PostfixEvaluator.evaluatePostfix("10 5 / 1 +"));
+    @ParameterizedTest(name = "Expression: \"{0}\" → Result: {1}")
+    @CsvSource({"'5 6 + 2 *', 22", "'7 2 + 3 *', 27", "'10 5 / 1 +', 3", "'8', 8", "'3 4 +', 7"})
+    @DisplayName("Valid postfix expressions")
+    void testValidExpressions(String expression, int expected) {
+        assertEquals(expected, PostfixEvaluator.evaluatePostfix(expression));
     }
 
     @Test
-    public void testInvalidExpression() {
+    @DisplayName("Should throw EmptyStackException for incomplete expression")
+    void testInvalidExpression() {
         assertThrows(EmptyStackException.class, () -> PostfixEvaluator.evaluatePostfix("5 +"));
     }
 
     @Test
-    public void testMoreThanOneStackSizeAfterEvaluation() {
+    @DisplayName("Should throw IllegalArgumentException for extra operands")
+    void testExtraOperands() {
         assertThrows(IllegalArgumentException.class, () -> PostfixEvaluator.evaluatePostfix("5 6 + 2 * 3"));
     }
+
+    @Test
+    @DisplayName("Should throw ArithmeticException for division by zero")
+    void testDivisionByZero() {
+        assertThrows(ArithmeticException.class, () -> PostfixEvaluator.evaluatePostfix("1 0 /"));
+    }
+
+    @Test
+    @DisplayName("Should throw IllegalArgumentException for invalid characters")
+    void testInvalidToken() {
+        assertThrows(IllegalArgumentException.class, () -> PostfixEvaluator.evaluatePostfix("1 a +"));
+    }
 }

From 75298bb3f4a4322cb15c3fd9bb981b40d8d158e9 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Mon, 21 Jul 2025 17:58:22 +0200
Subject: [PATCH 0895/1338] testing: improving `DequeTest` (#6410)

* testing: improving DequeTest

* testing: redundant case

* testing: fix to many static imports

* testing: add more test cases

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../datastructures/queues/DequeTest.java      | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java b/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java
index 1244a2e260d2..34b1ea2e0277 100644
--- a/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java
@@ -87,4 +87,38 @@ void testToString() {
         deque.addFirst(5);
         assertEquals("Head -> 5 <-> 10 <-> 20 <- Tail", deque.toString());
     }
+
+    @Test
+    void testAlternatingAddRemove() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addFirst(1);
+        deque.addLast(2);
+        deque.addFirst(0);
+        assertEquals(0, deque.pollFirst());
+        assertEquals(2, deque.pollLast());
+        assertEquals(1, deque.pollFirst());
+        org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty());
+    }
+
+    @Test
+    void testSizeAfterOperations() {
+        Deque<Integer> deque = new Deque<>();
+        assertEquals(0, deque.size());
+        deque.addFirst(1);
+        deque.addLast(2);
+        deque.addFirst(3);
+        assertEquals(3, deque.size());
+        deque.pollFirst();
+        deque.pollLast();
+        assertEquals(1, deque.size());
+    }
+
+    @Test
+    void testNullValues() {
+        Deque<String> deque = new Deque<>();
+        deque.addFirst(null);
+        assertNull(deque.peekFirst());
+        assertNull(deque.pollFirst());
+        org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty());
+    }
 }

From 2722b0ecc990983614ef0e5ef5c4a39fd979b516 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Mon, 21 Jul 2025 18:02:07 +0200
Subject: [PATCH 0896/1338] testing: improving `SkipListTest` (#6411)

* testing: improving SkipListTest

* style: fixed formatting

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../datastructures/lists/SkipListTest.java    | 119 +++++++++---------
 1 file changed, 62 insertions(+), 57 deletions(-)

diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java
index c572739ffbbf..16d1a015a4d9 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java
@@ -1,110 +1,115 @@
 package com.thealgorithms.datastructures.lists;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.Arrays;
 import java.util.stream.IntStream;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
 class SkipListTest {
 
+    private SkipList<String> skipList;
+
+    @BeforeEach
+    void setUp() {
+        skipList = new SkipList<>();
+    }
+
     @Test
-    void add() {
-        SkipList<String> skipList = new SkipList<>();
+    @DisplayName("Add element and verify size and retrieval")
+    void testAdd() {
         assertEquals(0, skipList.size());
 
         skipList.add("value");
 
-        print(skipList);
         assertEquals(1, skipList.size());
+        assertEquals("value", skipList.get(0));
     }
 
     @Test
-    void get() {
-        SkipList<String> skipList = new SkipList<>();
+    @DisplayName("Get retrieves correct element by index")
+    void testGet() {
         skipList.add("value");
-
-        String actualValue = skipList.get(0);
-
-        print(skipList);
-        assertEquals("value", actualValue);
+        assertEquals("value", skipList.get(0));
     }
 
     @Test
-    void contains() {
-        SkipList<String> skipList = createSkipList();
-        print(skipList);
-
-        boolean contains = skipList.contains("b");
-
-        assertTrue(contains);
+    @DisplayName("Contains returns true if element exists")
+    void testContains() {
+        skipList = createSkipList();
+        assertTrue(skipList.contains("b"));
+        assertTrue(skipList.contains("a"));
+        assertFalse(skipList.contains("z")); // negative test
     }
 
     @Test
-    void removeFromHead() {
-        SkipList<String> skipList = createSkipList();
-        String mostLeftElement = skipList.get(0);
+    @DisplayName("Remove element from head and check size and order")
+    void testRemoveFromHead() {
+        skipList = createSkipList();
+        String first = skipList.get(0);
         int initialSize = skipList.size();
-        print(skipList);
 
-        skipList.remove(mostLeftElement);
+        skipList.remove(first);
 
-        print(skipList);
         assertEquals(initialSize - 1, skipList.size());
+        assertFalse(skipList.contains(first));
     }
 
     @Test
-    void removeFromTail() {
-        SkipList<String> skipList = createSkipList();
-        String mostRightValue = skipList.get(skipList.size() - 1);
+    @DisplayName("Remove element from tail and check size and order")
+    void testRemoveFromTail() {
+        skipList = createSkipList();
+        String last = skipList.get(skipList.size() - 1);
         int initialSize = skipList.size();
-        print(skipList);
 
-        skipList.remove(mostRightValue);
+        skipList.remove(last);
 
-        print(skipList);
         assertEquals(initialSize - 1, skipList.size());
+        assertFalse(skipList.contains(last));
     }
 
     @Test
-    void checkSortedOnLowestLayer() {
-        SkipList<String> skipList = new SkipList<>();
+    @DisplayName("Elements should be sorted at base level")
+    void testSortedOrderOnBaseLevel() {
         String[] values = {"d", "b", "a", "c"};
         Arrays.stream(values).forEach(skipList::add);
-        print(skipList);
 
         String[] actualOrder = IntStream.range(0, values.length).mapToObj(skipList::get).toArray(String[] ::new);
 
-        assertArrayEquals(new String[] {"a", "b", "c", "d"}, actualOrder);
+        org.junit.jupiter.api.Assertions.assertArrayEquals(new String[] {"a", "b", "c", "d"}, actualOrder);
     }
 
-    private SkipList<String> createSkipList() {
-        SkipList<String> skipList = new SkipList<>();
-        String[] values = {
-            "a",
-            "b",
-            "c",
-            "d",
-            "e",
-            "f",
-            "g",
-            "h",
-            "i",
-            "j",
-            "k",
-        };
+    @Test
+    @DisplayName("Duplicate elements can be added and count correctly")
+    void testAddDuplicates() {
+        skipList.add("x");
+        skipList.add("x");
+        assertEquals(2, skipList.size());
+        assertEquals("x", skipList.get(0));
+        assertEquals("x", skipList.get(1));
+    }
+
+    @Test
+    @DisplayName("Add multiple and remove all")
+    void testClearViaRemovals() {
+        String[] values = {"a", "b", "c"};
         Arrays.stream(values).forEach(skipList::add);
-        return skipList;
+
+        for (String v : values) {
+            skipList.remove(v);
+        }
+
+        assertEquals(0, skipList.size());
     }
 
-    /**
-     * Print Skip List representation to console.
-     * Optional method not involved in testing process. Used only for visualisation purposes.
-     * @param skipList to print
-     */
-    private void print(SkipList<?> skipList) {
-        System.out.println(skipList);
+    private SkipList<String> createSkipList() {
+        SkipList<String> s = new SkipList<>();
+        String[] values = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k"};
+        Arrays.stream(values).forEach(s::add);
+        return s;
     }
 }

From 2dfad7ef8feecfc0a2e40f729427e62fdabc1a0d Mon Sep 17 00:00:00 2001
From: Nishitha Wihala <nishithawihala30@gmail.com>
Date: Mon, 21 Jul 2025 21:37:13 +0530
Subject: [PATCH 0897/1338] Add matrix multiplication with double[][] and unit
 tests (#6417)

* MatrixMultiplication.java created and updated.

* Add necessary comment to MatrixMultiplication.java

* Create MatrixMultiplicationTest.java

* method for 2 by 2 matrix multiplication is created

* Use assertMatrixEquals(), otherwise there can be error due to floating point arithmetic errors

* assertMatrixEquals method created and updated

* method created for 3by2 matrix multiply with 2by1 matrix

* method created for null matrix multiplication

* method for test matrix dimension error

* method for test empty matrix input

* testMultiply3by2and2by1 test case updated

* Check for empty matrices part updated

* Updated Unit test coverage

* files updated

* clean the code

* clean the code

* Updated files with google-java-format

* Updated files

* Updated files

* Updated files

* Updated files

* Add reference links and complexities

* Add test cases for 1by1 matrix and non-rectangular matrix

* Add reference links and complexities

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../matrix/MatrixMultiplication.java          |  69 ++++++++++++
 .../matrix/MatrixMultiplicationTest.java      | 101 ++++++++++++++++++
 2 files changed, 170 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/matrix/MatrixMultiplication.java
 create mode 100644 src/test/java/com/thealgorithms/matrix/MatrixMultiplicationTest.java

diff --git a/src/main/java/com/thealgorithms/matrix/MatrixMultiplication.java b/src/main/java/com/thealgorithms/matrix/MatrixMultiplication.java
new file mode 100644
index 000000000000..6467a438577b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/matrix/MatrixMultiplication.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.matrix;
+
+/**
+ * This class provides a method to perform matrix multiplication.
+ *
+ * <p>Matrix multiplication takes two 2D arrays (matrices) as input and
+ * produces their product, following the mathematical definition of
+ * matrix multiplication.
+ *
+ * <p>For more details:
+ * https://www.geeksforgeeks.org/java/java-program-to-multiply-two-matrices-of-any-size/
+ * https://en.wikipedia.org/wiki/Matrix_multiplication
+ *
+ * <p>Time Complexity: O(n^3) – where n is the dimension of the matrices
+ * (assuming square matrices for simplicity).
+ *
+ * <p>Space Complexity: O(n^2) – for storing the result matrix.
+ *
+ *
+ * @author Nishitha Wihala Pitigala
+ *
+ */
+
+public final class MatrixMultiplication {
+    private MatrixMultiplication() {
+    }
+
+    /**
+     * Multiplies two matrices.
+     *
+     * @param matrixA the first matrix rowsA x colsA
+     * @param matrixB the second matrix rowsB x colsB
+     * @return the product of the two matrices rowsA x colsB
+     * @throws IllegalArgumentException if the matrices cannot be multiplied
+     */
+    public static double[][] multiply(double[][] matrixA, double[][] matrixB) {
+        // Check the input matrices are not null
+        if (matrixA == null || matrixB == null) {
+            throw new IllegalArgumentException("Input matrices cannot be null");
+        }
+
+        // Check for empty matrices
+        if (matrixA.length == 0 || matrixB.length == 0 || matrixA[0].length == 0 || matrixB[0].length == 0) {
+            throw new IllegalArgumentException("Input matrices must not be empty");
+        }
+
+        // Validate the matrix dimensions
+        if (matrixA[0].length != matrixB.length) {
+            throw new IllegalArgumentException("Matrices cannot be multiplied: incompatible dimensions.");
+        }
+
+        int rowsA = matrixA.length;
+        int colsA = matrixA[0].length;
+        int colsB = matrixB[0].length;
+
+        // Initialize the result matrix with zeros
+        double[][] result = new double[rowsA][colsB];
+
+        // Perform matrix multiplication
+        for (int i = 0; i < rowsA; i++) {
+            for (int j = 0; j < colsB; j++) {
+                for (int k = 0; k < colsA; k++) {
+                    result[i][j] += matrixA[i][k] * matrixB[k][j];
+                }
+            }
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/matrix/MatrixMultiplicationTest.java b/src/test/java/com/thealgorithms/matrix/MatrixMultiplicationTest.java
new file mode 100644
index 000000000000..9463d33a18cb
--- /dev/null
+++ b/src/test/java/com/thealgorithms/matrix/MatrixMultiplicationTest.java
@@ -0,0 +1,101 @@
+package com.thealgorithms.matrix;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class MatrixMultiplicationTest {
+
+    private static final double EPSILON = 1e-9; // for floating point comparison
+
+    @Test
+    void testMultiply1by1() {
+        double[][] matrixA = {{1.0}};
+        double[][] matrixB = {{2.0}};
+        double[][] expected = {{2.0}};
+
+        double[][] result = MatrixMultiplication.multiply(matrixA, matrixB);
+        assertMatrixEquals(expected, result);
+    }
+
+    @Test
+    void testMultiply2by2() {
+        double[][] matrixA = {{1.0, 2.0}, {3.0, 4.0}};
+        double[][] matrixB = {{5.0, 6.0}, {7.0, 8.0}};
+        double[][] expected = {{19.0, 22.0}, {43.0, 50.0}};
+
+        double[][] result = MatrixMultiplication.multiply(matrixA, matrixB);
+        assertMatrixEquals(expected, result); // Use custom method due to floating point issues
+    }
+
+    @Test
+    void testMultiply3by2and2by1() {
+        double[][] matrixA = {{1.0, 2.0}, {3.0, 4.0}, {5.0, 6.0}};
+        double[][] matrixB = {{7.0}, {8.0}};
+        double[][] expected = {{23.0}, {53.0}, {83.0}};
+
+        double[][] result = MatrixMultiplication.multiply(matrixA, matrixB);
+        assertMatrixEquals(expected, result);
+    }
+
+    @Test
+    void testMultiplyNonRectangularMatrices() {
+        double[][] matrixA = {{1.0, 2.0, 3.0}, {4.0, 5.0, 6.0}};
+        double[][] matrixB = {{7.0, 8.0}, {9.0, 10.0}, {11.0, 12.0}};
+        double[][] expected = {{58.0, 64.0}, {139.0, 154.0}};
+
+        double[][] result = MatrixMultiplication.multiply(matrixA, matrixB);
+        assertMatrixEquals(expected, result);
+    }
+
+    @Test
+    void testNullMatrixA() {
+        double[][] b = {{1, 2}, {3, 4}};
+        assertThrows(IllegalArgumentException.class, () -> MatrixMultiplication.multiply(null, b));
+    }
+
+    @Test
+    void testNullMatrixB() {
+        double[][] a = {{1, 2}, {3, 4}};
+        assertThrows(IllegalArgumentException.class, () -> MatrixMultiplication.multiply(a, null));
+    }
+
+    @Test
+    void testMultiplyNull() {
+        double[][] matrixA = {{1.0, 2.0}, {3.0, 4.0}};
+        double[][] matrixB = null;
+
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> MatrixMultiplication.multiply(matrixA, matrixB));
+
+        String expectedMessage = "Input matrices cannot be null";
+        String actualMessage = exception.getMessage();
+
+        assertTrue(actualMessage.contains(expectedMessage));
+    }
+
+    @Test
+    void testIncompatibleDimensions() {
+        double[][] a = {{1.0, 2.0}};
+        double[][] b = {{1.0, 2.0}};
+        assertThrows(IllegalArgumentException.class, () -> MatrixMultiplication.multiply(a, b));
+    }
+
+    @Test
+    void testEmptyMatrices() {
+        double[][] a = new double[0][0];
+        double[][] b = new double[0][0];
+        assertThrows(IllegalArgumentException.class, () -> MatrixMultiplication.multiply(a, b));
+    }
+
+    private void assertMatrixEquals(double[][] expected, double[][] actual) {
+        assertEquals(expected.length, actual.length, "Row count mismatch");
+        for (int i = 0; i < expected.length; i++) {
+            assertEquals(expected[i].length, actual[i].length, "Column count mismatch at row " + i);
+            for (int j = 0; j < expected[i].length; j++) {
+                assertEquals(expected[i][j], actual[i][j], EPSILON, "Mismatch at (" + i + "," + j + ")");
+            }
+        }
+    }
+}

From c9cc8f469881ef611ed8b43fcf39c51e2de6fa4d Mon Sep 17 00:00:00 2001
From: IDDQD <kevinmwita7@gmail.com>
Date: Mon, 21 Jul 2025 19:11:13 +0300
Subject: [PATCH 0898/1338] Add cache with LIFO replacement policy (#6390)

* Added Random Replacement cache

* Implement cache with LIFO replacement policy

* Ran clang-format

* Make necessary variables final, replace HashMap.newHashMap(int capacity) with new HashMap<>(int capacity)

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../datastructures/caches/LIFOCache.java      | 563 ++++++++++++++++++
 .../datastructures/caches/LIFOCacheTest.java  | 341 +++++++++++
 2 files changed, 904 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/caches/LIFOCache.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/caches/LIFOCacheTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/caches/LIFOCache.java b/src/main/java/com/thealgorithms/datastructures/caches/LIFOCache.java
new file mode 100644
index 000000000000..df3d4da912fe
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/caches/LIFOCache.java
@@ -0,0 +1,563 @@
+package com.thealgorithms.datastructures.caches;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.BiConsumer;
+
+/**
+ * A thread-safe generic cache implementation using the Last-In-First-Out eviction policy.
+ * <p>
+ * The cache holds a fixed number of entries, defined by its capacity. When the cache is full and a
+ * new entry is added, the youngest entry in the cache is selected and evicted to make space.
+ * <p>
+ * Optionally, entries can have a time-to-live (TTL) in milliseconds. If a TTL is set, entries will
+ * automatically expire and be removed upon access or insertion attempts.
+ * <p>
+ * Features:
+ * <ul>
+ *     <li>Removes youngest entry when capacity is exceeded</li>
+ *     <li>Optional TTL (time-to-live in milliseconds) per entry or default TTL for all entries</li>
+ *     <li>Thread-safe access using locking</li>
+ *     <li>Hit and miss counters for cache statistics</li>
+ *     <li>Eviction listener callback support</li>
+ * </ul>
+ *
+ * @param <K> the type of keys maintained by this cache
+ * @param <V> the type of mapped values
+ * See <a href="https://en.wikipedia.org/wiki/Cache_replacement_policies#Last_in_first_out_(LIFO)_or_First_in_last_out_(FILO)">LIFO</a>
+ * @author Kevin Babu (<a href="https://www.github.com/KevinMwita7">GitHub</a>)
+ */
+public final class LIFOCache<K, V> {
+
+    private final int capacity;
+    private final long defaultTTL;
+    private final Map<K, CacheEntry<V>> cache;
+    private final Lock lock;
+    private final Deque<K> keys;
+    private long hits = 0;
+    private long misses = 0;
+    private final BiConsumer<K, V> evictionListener;
+    private final EvictionStrategy<K, V> evictionStrategy;
+
+    /**
+     * Internal structure to store value + expiry timestamp.
+     *
+     * @param <V> the type of the value being cached
+     */
+    private static class CacheEntry<V> {
+        V value;
+        long expiryTime;
+
+        /**
+         * Constructs a new {@code CacheEntry} with the specified value and time-to-live (TTL).
+         * If TTL is 0, the entry is kept indefinitely, that is, unless it is the first value,
+         * then it will be removed according to the LIFO principle
+         *
+         * @param value     the value to cache
+         * @param ttlMillis the time-to-live in milliseconds
+         */
+        CacheEntry(V value, long ttlMillis) {
+            this.value = value;
+            if (ttlMillis == 0) {
+                this.expiryTime = Long.MAX_VALUE;
+            } else {
+                this.expiryTime = System.currentTimeMillis() + ttlMillis;
+            }
+        }
+
+        /**
+         * Checks if the cache entry has expired.
+         *
+         * @return {@code true} if the current time is past the expiration time; {@code false} otherwise
+         */
+        boolean isExpired() {
+            return System.currentTimeMillis() > expiryTime;
+        }
+    }
+
+    /**
+     * Constructs a new {@code LIFOCache} instance using the provided {@link Builder}.
+     *
+     * <p>This constructor initializes the cache with the specified capacity and default TTL,
+     * sets up internal data structures (a {@code HashMap} for cache entries,
+     * {an @code ArrayDeque}, for key storage, and configures eviction.
+     *
+     * @param builder the {@code Builder} object containing configuration parameters
+     */
+    private LIFOCache(Builder<K, V> builder) {
+        this.capacity = builder.capacity;
+        this.defaultTTL = builder.defaultTTL;
+        this.cache = new HashMap<>(builder.capacity);
+        this.keys = new ArrayDeque<>(builder.capacity);
+        this.lock = new ReentrantLock();
+        this.evictionListener = builder.evictionListener;
+        this.evictionStrategy = builder.evictionStrategy;
+    }
+
+    /**
+     * Retrieves the value associated with the specified key from the cache.
+     *
+     * <p>If the key is not present or the corresponding entry has expired, this method
+     * returns {@code null}. If an expired entry is found, it will be removed and the
+     * eviction listener (if any) will be notified. Cache hit-and-miss statistics are
+     * also updated accordingly.
+     *
+     * @param key the key whose associated value is to be returned; must not be {@code null}
+     * @return the cached value associated with the key, or {@code null} if not present or expired
+     * @throws IllegalArgumentException if {@code key} is {@code null}
+     */
+    public V get(K key) {
+        if (key == null) {
+            throw new IllegalArgumentException("Key must not be null");
+        }
+
+        lock.lock();
+        try {
+            evictionStrategy.onAccess(this);
+
+            final CacheEntry<V> entry = cache.get(key);
+            if (entry == null || entry.isExpired()) {
+                if (entry != null) {
+                    cache.remove(key);
+                    keys.remove(key);
+                    notifyEviction(key, entry.value);
+                }
+                misses++;
+                return null;
+            }
+            hits++;
+            return entry.value;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Adds a key-value pair to the cache using the default time-to-live (TTL).
+     *
+     * <p>The key may overwrite an existing entry. The actual insertion is delegated
+     * to the overloaded {@link #put(K, V, long)} method.
+     *
+     * @param key   the key to cache the value under
+     * @param value the value to be cached
+     */
+    public void put(K key, V value) {
+        put(key, value, defaultTTL);
+    }
+
+    /**
+     * Adds a key-value pair to the cache with a specified time-to-live (TTL).
+     *
+     * <p>If the key already exists, its value is removed, re-inserted at tail and its TTL is reset.
+     * If the key does not exist and the cache is full, the youngest entry is evicted to make space.
+     * Expired entries are also cleaned up prior to any eviction. The eviction listener
+     * is notified when an entry gets evicted.
+     *
+     * @param key        the key to associate with the cached value; must not be {@code null}
+     * @param value      the value to be cached; must not be {@code null}
+     * @param ttlMillis  the time-to-live for this entry in milliseconds; must be >= 0
+     * @throws IllegalArgumentException if {@code key} or {@code value} is {@code null}, or if {@code ttlMillis} is negative
+     */
+    public void put(K key, V value, long ttlMillis) {
+        if (key == null || value == null) {
+            throw new IllegalArgumentException("Key and value must not be null");
+        }
+        if (ttlMillis < 0) {
+            throw new IllegalArgumentException("TTL must be >= 0");
+        }
+
+        lock.lock();
+        try {
+            // If key already exists, remove it. It will later be re-inserted at top of stack
+            keys.remove(key);
+            final CacheEntry<V> oldEntry = cache.remove(key);
+            if (oldEntry != null && !oldEntry.isExpired()) {
+                notifyEviction(key, oldEntry.value);
+            }
+
+            // Evict expired entries to make space for new entry
+            evictExpired();
+
+            // If no expired entry was removed, remove the youngest
+            if (cache.size() >= capacity) {
+                final K youngestKey = keys.pollLast();
+                final CacheEntry<V> youngestEntry = cache.remove(youngestKey);
+                notifyEviction(youngestKey, youngestEntry.value);
+            }
+
+            // Insert new entry at tail
+            keys.add(key);
+            cache.put(key, new CacheEntry<>(value, ttlMillis));
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Removes all expired entries from the cache.
+     *
+     * <p>This method iterates through the list of cached keys and checks each associated
+     * entry for expiration. Expired entries are removed the cache map. For each eviction,
+     * the eviction listener is notified.
+     */
+    private int evictExpired() {
+        int count = 0;
+        final Iterator<K> it = keys.iterator();
+
+        while (it.hasNext()) {
+            final K k = it.next();
+            final CacheEntry<V> entry = cache.get(k);
+            if (entry != null && entry.isExpired()) {
+                it.remove();
+                cache.remove(k);
+                notifyEviction(k, entry.value);
+                count++;
+            }
+        }
+
+        return count;
+    }
+
+    /**
+     * Removes the specified key and its associated entry from the cache.
+     *
+     * @param key the key to remove from the cache;
+     * @return the value associated with the key;  or {@code null} if no such key exists
+     */
+    public V removeKey(K key) {
+        if (key == null) {
+            throw new IllegalArgumentException("Key cannot be null");
+        }
+        lock.lock();
+        try {
+            final CacheEntry<V> entry = cache.remove(key);
+            keys.remove(key);
+
+            // No such key in cache
+            if (entry == null) {
+                return null;
+            }
+
+            notifyEviction(key, entry.value);
+            return entry.value;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Notifies the eviction listener, if one is registered, that a key-value pair has been evicted.
+     *
+     * <p>If the {@code evictionListener} is not {@code null}, it is invoked with the provided key
+     * and value. Any exceptions thrown by the listener are caught and logged to standard error,
+     * preventing them from disrupting cache operations.
+     *
+     * @param key   the key that was evicted
+     * @param value the value that was associated with the evicted key
+     */
+    private void notifyEviction(K key, V value) {
+        if (evictionListener != null) {
+            try {
+                evictionListener.accept(key, value);
+            } catch (Exception e) {
+                System.err.println("Eviction listener failed: " + e.getMessage());
+            }
+        }
+    }
+
+    /**
+     * Returns the number of successful cache lookups (hits).
+     *
+     * @return the number of cache hits
+     */
+    public long getHits() {
+        lock.lock();
+        try {
+            return hits;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns the number of failed cache lookups (misses), including expired entries.
+     *
+     * @return the number of cache misses
+     */
+    public long getMisses() {
+        lock.lock();
+        try {
+            return misses;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns the current number of entries in the cache, excluding expired ones.
+     *
+     * @return the current cache size
+     */
+    public int size() {
+        lock.lock();
+        try {
+            evictionStrategy.onAccess(this);
+
+            int count = 0;
+            for (CacheEntry<V> entry : cache.values()) {
+                if (!entry.isExpired()) {
+                    ++count;
+                }
+            }
+            return count;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Removes all entries from the cache, regardless of their expiration status.
+     *
+     * <p>This method clears the internal cache map entirely, resets the hit-and-miss counters,
+     * and notifies the eviction listener (if any) for each removed entry.
+     * Note that expired entries are treated the same as active ones for the purpose of clearing.
+     *
+     * <p>This operation acquires the internal lock to ensure thread safety.
+     */
+    public void clear() {
+        lock.lock();
+        try {
+            for (Map.Entry<K, CacheEntry<V>> entry : cache.entrySet()) {
+                notifyEviction(entry.getKey(), entry.getValue().value);
+            }
+            keys.clear();
+            cache.clear();
+            hits = 0;
+            misses = 0;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns a set of all keys currently stored in the cache that have not expired.
+     *
+     * <p>This method iterates through the cache and collects the keys of all non-expired entries.
+     * Expired entries are ignored but not removed. If you want to ensure expired entries are cleaned up,
+     * consider invoking {@link EvictionStrategy#onAccess(LIFOCache)} or calling {@link #evictExpired()} manually.
+     *
+     * <p>This operation acquires the internal lock to ensure thread safety.
+     *
+     * @return a set containing all non-expired keys currently in the cache
+     */
+    public Set<K> getAllKeys() {
+        lock.lock();
+        try {
+            final Set<K> result = new HashSet<>();
+
+            for (Map.Entry<K, CacheEntry<V>> entry : cache.entrySet()) {
+                if (!entry.getValue().isExpired()) {
+                    result.add(entry.getKey());
+                }
+            }
+
+            return result;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns the current {@link EvictionStrategy} used by this cache instance.
+
+     * @return the eviction strategy currently assigned to this cache
+     */
+    public EvictionStrategy<K, V> getEvictionStrategy() {
+        return evictionStrategy;
+    }
+
+    /**
+     * Returns a string representation of the cache, including metadata and current non-expired entries.
+     *
+     * <p>The returned string includes the cache's capacity, current size (excluding expired entries),
+     * hit-and-miss counts, and a map of all non-expired key-value pairs. This method acquires a lock
+     * to ensure thread-safe access.
+     *
+     * @return a string summarizing the state of the cache
+     */
+    @Override
+    public String toString() {
+        lock.lock();
+        try {
+            final Map<K, V> visible = new LinkedHashMap<>();
+            for (Map.Entry<K, CacheEntry<V>> entry : cache.entrySet()) {
+                if (!entry.getValue().isExpired()) {
+                    visible.put(entry.getKey(), entry.getValue().value);
+                }
+            }
+            return String.format("Cache(capacity=%d, size=%d, hits=%d, misses=%d, entries=%s)", capacity, visible.size(), hits, misses, visible);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * A strategy interface for controlling when expired entries are evicted from the cache.
+     *
+     * <p>Implementations decide whether and when to trigger {@link LIFOCache#evictExpired()} based
+     * on cache usage patterns. This allows for flexible eviction behaviour such as periodic cleanup,
+     * or no automatic cleanup.
+     *
+     * @param <K> the type of keys maintained by the cache
+     * @param <V> the type of cached values
+     */
+    public interface EvictionStrategy<K, V> {
+        /**
+         * Called on each cache access (e.g., {@link LIFOCache#get(Object)}) to optionally trigger eviction.
+         *
+         * @param cache the cache instance on which this strategy is applied
+         * @return the number of expired entries evicted during this access
+         */
+        int onAccess(LIFOCache<K, V> cache);
+    }
+
+    /**
+     * An eviction strategy that performs eviction of expired entries on each call.
+     *
+     * @param <K> the type of keys
+     * @param <V> the type of values
+     */
+    public static class ImmediateEvictionStrategy<K, V> implements EvictionStrategy<K, V> {
+        @Override
+        public int onAccess(LIFOCache<K, V> cache) {
+            return cache.evictExpired();
+        }
+    }
+
+    /**
+     * An eviction strategy that triggers eviction on every fixed number of accesses.
+     *
+     * <p>This deterministic strategy ensures cleanup occurs at predictable intervals,
+     * ideal for moderately active caches where memory usage is a concern.
+     *
+     * @param <K> the type of keys
+     * @param <V> the type of values
+     */
+    public static class PeriodicEvictionStrategy<K, V> implements EvictionStrategy<K, V> {
+        private final int interval;
+        private final AtomicInteger counter = new AtomicInteger();
+
+        /**
+         * Constructs a periodic eviction strategy.
+         *
+         * @param interval the number of accesses between evictions; must be > 0
+         * @throws IllegalArgumentException if {@code interval} is less than or equal to 0
+         */
+        public PeriodicEvictionStrategy(int interval) {
+            if (interval <= 0) {
+                throw new IllegalArgumentException("Interval must be > 0");
+            }
+            this.interval = interval;
+        }
+
+        @Override
+        public int onAccess(LIFOCache<K, V> cache) {
+            if (counter.incrementAndGet() % interval == 0) {
+                return cache.evictExpired();
+            }
+
+            return 0;
+        }
+    }
+
+    /**
+     * A builder for constructing a {@link LIFOCache} instance with customizable settings.
+     *
+     * <p>Allows configuring capacity, default TTL, eviction listener, and a pluggable eviction
+     * strategy. Call {@link #build()} to create the configured cache instance.
+     *
+     * @param <K> the type of keys maintained by the cache
+     * @param <V> the type of values stored in the cache
+     */
+    public static class Builder<K, V> {
+        private final int capacity;
+        private long defaultTTL = 0;
+        private BiConsumer<K, V> evictionListener;
+        private EvictionStrategy<K, V> evictionStrategy = new LIFOCache.ImmediateEvictionStrategy<>();
+        /**
+         * Creates a new {@code Builder} with the specified cache capacity.
+         *
+         * @param capacity the maximum number of entries the cache can hold; must be > 0
+         * @throws IllegalArgumentException if {@code capacity} is less than or equal to 0
+         */
+        public Builder(int capacity) {
+            if (capacity <= 0) {
+                throw new IllegalArgumentException("Capacity must be > 0");
+            }
+            this.capacity = capacity;
+        }
+
+        /**
+         * Sets the default time-to-live (TTL) in milliseconds for cache entries.
+         *
+         * @param ttlMillis the TTL duration in milliseconds; must be >= 0
+         * @return this builder instance for chaining
+         * @throws IllegalArgumentException if {@code ttlMillis} is negative
+         */
+        public Builder<K, V> defaultTTL(long ttlMillis) {
+            if (ttlMillis < 0) {
+                throw new IllegalArgumentException("Default TTL must be >= 0");
+            }
+            this.defaultTTL = ttlMillis;
+            return this;
+        }
+
+        /**
+         * Sets an eviction listener to be notified when entries are evicted from the cache.
+         *
+         * @param listener a {@link BiConsumer} that accepts evicted keys and values; must not be {@code null}
+         * @return this builder instance for chaining
+         * @throws IllegalArgumentException if {@code listener} is {@code null}
+         */
+        public Builder<K, V> evictionListener(BiConsumer<K, V> listener) {
+            if (listener == null) {
+                throw new IllegalArgumentException("Listener must not be null");
+            }
+            this.evictionListener = listener;
+            return this;
+        }
+
+        /**
+         * Builds and returns a new {@link LIFOCache} instance with the configured parameters.
+         *
+         * @return a fully configured {@code LIFOCache} instance
+         */
+        public LIFOCache<K, V> build() {
+            return new LIFOCache<>(this);
+        }
+
+        /**
+         * Sets the eviction strategy used to determine when to clean up expired entries.
+         *
+         * @param strategy an {@link EvictionStrategy} implementation; must not be {@code null}
+         * @return this builder instance
+         * @throws IllegalArgumentException if {@code strategy} is {@code null}
+         */
+        public Builder<K, V> evictionStrategy(EvictionStrategy<K, V> strategy) {
+            if (strategy == null) {
+                throw new IllegalArgumentException("Eviction strategy must not be null");
+            }
+            this.evictionStrategy = strategy;
+            return this;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/caches/LIFOCacheTest.java b/src/test/java/com/thealgorithms/datastructures/caches/LIFOCacheTest.java
new file mode 100644
index 000000000000..df60a393b136
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/caches/LIFOCacheTest.java
@@ -0,0 +1,341 @@
+package com.thealgorithms.datastructures.caches;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.function.Executable;
+
+class LIFOCacheTest {
+    private LIFOCache<String, String> cache;
+    private Set<String> evictedKeys;
+    private List<String> evictedValues;
+
+    @BeforeEach
+    void setUp() {
+        evictedKeys = new HashSet<>();
+        evictedValues = new ArrayList<>();
+
+        cache = new LIFOCache.Builder<String, String>(3)
+                    .defaultTTL(1000)
+                    .evictionListener((k, v) -> {
+                        evictedKeys.add(k);
+                        evictedValues.add(v);
+                    })
+                    .build();
+    }
+
+    @Test
+    void testPutAndGet() {
+        cache.put("a", "apple");
+        Assertions.assertEquals("apple", cache.get("a"));
+    }
+
+    @Test
+    void testOverwriteValue() {
+        cache.put("a", "apple");
+        cache.put("a", "avocado");
+        Assertions.assertEquals("avocado", cache.get("a"));
+    }
+
+    @Test
+    void testExpiration() throws InterruptedException {
+        cache.put("temp", "value", 100);
+        Thread.sleep(200);
+        Assertions.assertNull(cache.get("temp"));
+        Assertions.assertTrue(evictedKeys.contains("temp"));
+    }
+
+    @Test
+    void testEvictionOnCapacity() {
+        cache.put("a", "alpha");
+        cache.put("b", "bravo");
+        cache.put("c", "charlie");
+        cache.put("d", "delta");
+
+        int size = cache.size();
+        Assertions.assertEquals(3, size);
+        Assertions.assertEquals(1, evictedKeys.size());
+        Assertions.assertEquals(1, evictedValues.size());
+        Assertions.assertEquals("charlie", evictedValues.getFirst());
+    }
+
+    @Test
+    void testEvictionListener() {
+        cache.put("x", "one");
+        cache.put("y", "two");
+        cache.put("z", "three");
+        cache.put("w", "four");
+
+        Assertions.assertFalse(evictedKeys.isEmpty());
+        Assertions.assertFalse(evictedValues.isEmpty());
+    }
+
+    @Test
+    void testHitsAndMisses() {
+        cache.put("a", "apple");
+        Assertions.assertEquals("apple", cache.get("a"));
+        Assertions.assertNull(cache.get("b"));
+        Assertions.assertEquals(1, cache.getHits());
+        Assertions.assertEquals(1, cache.getMisses());
+    }
+
+    @Test
+    void testSizeExcludesExpired() throws InterruptedException {
+        cache.put("a", "a", 100);
+        cache.put("b", "b", 100);
+        cache.put("c", "c", 100);
+        Thread.sleep(150);
+        Assertions.assertEquals(0, cache.size());
+    }
+
+    @Test
+    void testSizeIncludesFresh() {
+        cache.put("a", "a", 1000);
+        cache.put("b", "b", 1000);
+        cache.put("c", "c", 1000);
+        Assertions.assertEquals(3, cache.size());
+    }
+
+    @Test
+    void testToStringDoesNotExposeExpired() throws InterruptedException {
+        cache.put("live", "alive");
+        cache.put("dead", "gone", 100);
+        Thread.sleep(150);
+        String result = cache.toString();
+        Assertions.assertTrue(result.contains("live"));
+        Assertions.assertFalse(result.contains("dead"));
+    }
+
+    @Test
+    void testNullKeyGetThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.get(null));
+    }
+
+    @Test
+    void testPutNullKeyThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.put(null, "v"));
+    }
+
+    @Test
+    void testPutNullValueThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.put("k", null));
+    }
+
+    @Test
+    void testPutNegativeTTLThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.put("k", "v", -1));
+    }
+
+    @Test
+    void testBuilderNegativeCapacityThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new LIFOCache.Builder<>(0));
+    }
+
+    @Test
+    void testBuilderNullEvictionListenerThrows() {
+        LIFOCache.Builder<String, String> builder = new LIFOCache.Builder<>(1);
+        Assertions.assertThrows(IllegalArgumentException.class, () -> builder.evictionListener(null));
+    }
+
+    @Test
+    void testEvictionListenerExceptionDoesNotCrash() {
+        LIFOCache<String, String> listenerCache = new LIFOCache.Builder<String, String>(1).evictionListener((k, v) -> { throw new RuntimeException("Exception"); }).build();
+
+        listenerCache.put("a", "a");
+        listenerCache.put("b", "b");
+        Assertions.assertDoesNotThrow(() -> listenerCache.get("a"));
+    }
+
+    @Test
+    void testTtlZeroThrowsIllegalArgumentException() {
+        Executable exec = () -> new LIFOCache.Builder<String, String>(3).defaultTTL(-1).build();
+        Assertions.assertThrows(IllegalArgumentException.class, exec);
+    }
+
+    @Test
+    void testPeriodicEvictionStrategyEvictsAtInterval() throws InterruptedException {
+        LIFOCache<String, String> periodicCache = new LIFOCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(new LIFOCache.PeriodicEvictionStrategy<>(3)).build();
+
+        periodicCache.put("x", "1");
+        Thread.sleep(100);
+        int ev1 = periodicCache.getEvictionStrategy().onAccess(periodicCache);
+        int ev2 = periodicCache.getEvictionStrategy().onAccess(periodicCache);
+        int ev3 = periodicCache.getEvictionStrategy().onAccess(periodicCache);
+
+        Assertions.assertEquals(0, ev1);
+        Assertions.assertEquals(0, ev2);
+        Assertions.assertEquals(1, ev3, "Eviction should happen on the 3rd access");
+        Assertions.assertEquals(0, periodicCache.size());
+    }
+
+    @Test
+    void testPeriodicEvictionStrategyThrowsExceptionIfIntervalLessThanOrEqual0() {
+        Executable executable = () -> new LIFOCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(new LIFOCache.PeriodicEvictionStrategy<>(0)).build();
+
+        Assertions.assertThrows(IllegalArgumentException.class, executable);
+    }
+
+    @Test
+    void testImmediateEvictionStrategyStrategyEvictsOnEachCall() throws InterruptedException {
+        LIFOCache<String, String> immediateEvictionStrategy = new LIFOCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(new LIFOCache.ImmediateEvictionStrategy<>()).build();
+
+        immediateEvictionStrategy.put("x", "1");
+        Thread.sleep(100);
+        int evicted = immediateEvictionStrategy.getEvictionStrategy().onAccess(immediateEvictionStrategy);
+
+        Assertions.assertEquals(1, evicted);
+    }
+
+    @Test
+    void testBuilderThrowsExceptionIfEvictionStrategyNull() {
+        Executable executable = () -> new LIFOCache.Builder<String, String>(10).defaultTTL(50).evictionStrategy(null).build();
+
+        Assertions.assertThrows(IllegalArgumentException.class, executable);
+    }
+
+    @Test
+    void testReturnsCorrectStrategyInstance() {
+        LIFOCache.EvictionStrategy<String, String> strategy = new LIFOCache.ImmediateEvictionStrategy<>();
+
+        LIFOCache<String, String> newCache = new LIFOCache.Builder<String, String>(10).defaultTTL(1000).evictionStrategy(strategy).build();
+
+        Assertions.assertSame(strategy, newCache.getEvictionStrategy(), "Returned strategy should be the same instance");
+    }
+
+    @Test
+    void testDefaultStrategyIsImmediateEvictionStrategy() {
+        LIFOCache<String, String> newCache = new LIFOCache.Builder<String, String>(5).defaultTTL(1000).build();
+
+        Assertions.assertInstanceOf(LIFOCache.ImmediateEvictionStrategy.class, newCache.getEvictionStrategy(), "Default strategy should be ImmediateEvictionStrategyStrategy");
+    }
+
+    @Test
+    void testGetEvictionStrategyIsNotNull() {
+        LIFOCache<String, String> newCache = new LIFOCache.Builder<String, String>(5).build();
+
+        Assertions.assertNotNull(newCache.getEvictionStrategy(), "Eviction strategy should never be null");
+    }
+
+    @Test
+    void testRemoveKeyRemovesExistingKey() {
+        cache.put("A", "Alpha");
+        cache.put("B", "Beta");
+
+        Assertions.assertEquals("Alpha", cache.get("A"));
+        Assertions.assertEquals("Beta", cache.get("B"));
+
+        String removed = cache.removeKey("A");
+        Assertions.assertEquals("Alpha", removed);
+
+        Assertions.assertNull(cache.get("A"));
+        Assertions.assertEquals(1, cache.size());
+    }
+
+    @Test
+    void testRemoveKeyReturnsNullIfKeyNotPresent() {
+        cache.put("X", "X-ray");
+
+        Assertions.assertNull(cache.removeKey("NonExistent"));
+        Assertions.assertEquals(1, cache.size());
+    }
+
+    @Test
+    void testRemoveKeyHandlesExpiredEntry() throws InterruptedException {
+        LIFOCache<String, String> expiringCache = new LIFOCache.Builder<String, String>(2).defaultTTL(100).evictionStrategy(new LIFOCache.ImmediateEvictionStrategy<>()).build();
+
+        expiringCache.put("T", "Temporary");
+
+        Thread.sleep(200);
+
+        String removed = expiringCache.removeKey("T");
+        Assertions.assertEquals("Temporary", removed);
+        Assertions.assertNull(expiringCache.get("T"));
+    }
+
+    @Test
+    void testRemoveKeyThrowsIfKeyIsNull() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> cache.removeKey(null));
+    }
+
+    @Test
+    void testRemoveKeyTriggersEvictionListener() {
+        AtomicInteger evictedCount = new AtomicInteger();
+
+        LIFOCache<String, String> localCache = new LIFOCache.Builder<String, String>(2).evictionListener((key, value) -> evictedCount.incrementAndGet()).build();
+
+        localCache.put("A", "Apple");
+        localCache.put("B", "Banana");
+
+        localCache.removeKey("A");
+
+        Assertions.assertEquals(1, evictedCount.get(), "Eviction listener should have been called once");
+    }
+
+    @Test
+    void testRemoveKeyDoestNotAffectOtherKeys() {
+        cache.put("A", "Alpha");
+        cache.put("B", "Beta");
+        cache.put("C", "Gamma");
+
+        cache.removeKey("B");
+
+        Assertions.assertEquals("Alpha", cache.get("A"));
+        Assertions.assertNull(cache.get("B"));
+        Assertions.assertEquals("Gamma", cache.get("C"));
+    }
+
+    @Test
+    void testEvictionListenerExceptionDoesNotPropagate() {
+        LIFOCache<String, String> localCache = new LIFOCache.Builder<String, String>(1).evictionListener((key, value) -> { throw new RuntimeException(); }).build();
+
+        localCache.put("A", "Apple");
+
+        Assertions.assertDoesNotThrow(() -> localCache.put("B", "Beta"));
+    }
+
+    @Test
+    void testGetKeysReturnsAllFreshKeys() {
+        cache.put("A", "Alpha");
+        cache.put("B", "Beta");
+        cache.put("G", "Gamma");
+
+        Set<String> expectedKeys = Set.of("A", "B", "G");
+        Assertions.assertEquals(expectedKeys, cache.getAllKeys());
+    }
+
+    @Test
+    void testGetKeysIgnoresExpiredKeys() throws InterruptedException {
+        cache.put("A", "Alpha");
+        cache.put("B", "Beta");
+        cache.put("G", "Gamma", 100);
+
+        Set<String> expectedKeys = Set.of("A", "B");
+        Thread.sleep(200);
+        Assertions.assertEquals(expectedKeys, cache.getAllKeys());
+    }
+
+    @Test
+    void testClearRemovesAllEntries() {
+        cache.put("A", "Alpha");
+        cache.put("B", "Beta");
+        cache.put("G", "Gamma");
+
+        cache.clear();
+        Assertions.assertEquals(0, cache.size());
+    }
+
+    @Test
+    void testGetExpiredKeyIncrementsMissesCount() throws InterruptedException {
+        LIFOCache<String, String> localCache = new LIFOCache.Builder<String, String>(3).evictionStrategy(cache -> 0).defaultTTL(10).build();
+        localCache.put("A", "Alpha");
+        Thread.sleep(100);
+        String value = localCache.get("A");
+        Assertions.assertEquals(1, localCache.getMisses());
+        Assertions.assertNull(value);
+    }
+}

From 9a46339bec304158465aa497f7a062dbb7231307 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Mon, 21 Jul 2025 19:05:48 +0200
Subject: [PATCH 0899/1338] Update DIRECTORY.md (#6426)

Co-authored-by: DenizAltunkapan <DenizAltunkapan@users.noreply.github.com>
---
 DIRECTORY.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index cae5b8067c41..c52952edada4 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -132,6 +132,7 @@
           - 📁 **caches**
             - 📄 [FIFOCache](src/main/java/com/thealgorithms/datastructures/caches/FIFOCache.java)
             - 📄 [LFUCache](src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java)
+            - 📄 [LIFOCache](src/main/java/com/thealgorithms/datastructures/caches/LIFOCache.java)
             - 📄 [LRUCache](src/main/java/com/thealgorithms/datastructures/caches/LRUCache.java)
             - 📄 [MRUCache](src/main/java/com/thealgorithms/datastructures/caches/MRUCache.java)
             - 📄 [RRCache](src/main/java/com/thealgorithms/datastructures/caches/RRCache.java)
@@ -488,6 +489,7 @@
           - 📄 [Volume](src/main/java/com/thealgorithms/maths/Volume.java)
         - 📁 **matrix**
           - 📄 [InverseOfMatrix](src/main/java/com/thealgorithms/matrix/InverseOfMatrix.java)
+          - 📄 [MatrixMultiplication](src/main/java/com/thealgorithms/matrix/MatrixMultiplication.java)
           - 📄 [MatrixRank](src/main/java/com/thealgorithms/matrix/MatrixRank.java)
           - 📄 [MatrixTranspose](src/main/java/com/thealgorithms/matrix/MatrixTranspose.java)
           - 📄 [MedianOfMatrix](src/main/java/com/thealgorithms/matrix/MedianOfMatrix.java)
@@ -869,6 +871,7 @@
           - 📁 **caches**
             - 📄 [FIFOCacheTest](src/test/java/com/thealgorithms/datastructures/caches/FIFOCacheTest.java)
             - 📄 [LFUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/LFUCacheTest.java)
+            - 📄 [LIFOCacheTest](src/test/java/com/thealgorithms/datastructures/caches/LIFOCacheTest.java)
             - 📄 [LRUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java)
             - 📄 [MRUCacheTest](src/test/java/com/thealgorithms/datastructures/caches/MRUCacheTest.java)
             - 📄 [RRCacheTest](src/test/java/com/thealgorithms/datastructures/caches/RRCacheTest.java)
@@ -1177,6 +1180,7 @@
             - 📄 [PrimeFactorizationTest](src/test/java/com/thealgorithms/maths/prime/PrimeFactorizationTest.java)
         - 📁 **matrix**
           - 📄 [InverseOfMatrixTest](src/test/java/com/thealgorithms/matrix/InverseOfMatrixTest.java)
+          - 📄 [MatrixMultiplicationTest](src/test/java/com/thealgorithms/matrix/MatrixMultiplicationTest.java)
           - 📄 [MatrixRankTest](src/test/java/com/thealgorithms/matrix/MatrixRankTest.java)
           - 📄 [MatrixTransposeTest](src/test/java/com/thealgorithms/matrix/MatrixTransposeTest.java)
           - 📄 [MatrixUtilTest](src/test/java/com/thealgorithms/matrix/MatrixUtilTest.java)

From 78b62191ab09c566262b7a78d995def74d8b08e8 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Tue, 22 Jul 2025 18:49:37 +0200
Subject: [PATCH 0900/1338] testing: improving `GenerateSubsetsTest` (#6412)

* testing: improving GenerateSubsetsTest

* testing: change List to more common Iterable

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../recursion/GenerateSubsetsTest.java        | 38 ++++++++++---------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java b/src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java
index b92d1406b0a7..983552722781 100644
--- a/src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java
+++ b/src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java
@@ -1,36 +1,40 @@
 package com.thealgorithms.recursion;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
 
+import java.util.Arrays;
 import java.util.List;
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
 public final class GenerateSubsetsTest {
 
     @Test
-    void subsetRecursionTestOne() {
-        String str = "abc";
-        String[] expected = new String[] {"abc", "ab", "ac", "a", "bc", "b", "c", ""};
-
-        List<String> ans = GenerateSubsets.subsetRecursion(str);
-        assertArrayEquals(ans.toArray(), expected);
+    @DisplayName("Subsets of 'abc'")
+    void testSubsetsOfABC() {
+        assertSubsets("abc", Arrays.asList("abc", "ab", "ac", "a", "bc", "b", "c", ""));
     }
 
     @Test
-    void subsetRecursionTestTwo() {
-        String str = "cbf";
-        String[] expected = new String[] {"cbf", "cb", "cf", "c", "bf", "b", "f", ""};
+    @DisplayName("Subsets of 'cbf'")
+    void testSubsetsOfCBF() {
+        assertSubsets("cbf", Arrays.asList("cbf", "cb", "cf", "c", "bf", "b", "f", ""));
+    }
 
-        List<String> ans = GenerateSubsets.subsetRecursion(str);
-        assertArrayEquals(ans.toArray(), expected);
+    @Test
+    @DisplayName("Subsets of 'aba' with duplicates")
+    void testSubsetsWithDuplicateChars() {
+        assertSubsets("aba", Arrays.asList("aba", "ab", "aa", "a", "ba", "b", "a", ""));
     }
 
     @Test
-    void subsetRecursionTestThree() {
-        String str = "aba";
-        String[] expected = new String[] {"aba", "ab", "aa", "a", "ba", "b", "a", ""};
+    @DisplayName("Subsets of empty string")
+    void testEmptyInput() {
+        assertSubsets("", List.of(""));
+    }
 
-        List<String> ans = GenerateSubsets.subsetRecursion(str);
-        assertArrayEquals(ans.toArray(), expected);
+    private void assertSubsets(String input, Iterable<String> expected) {
+        List<String> actual = GenerateSubsets.subsetRecursion(input);
+        assertIterableEquals(expected, actual, "Subsets do not match for input: " + input);
     }
 }

From bbbc1dd9462e6de392e7dac192a6cac974e7ffd2 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Tue, 22 Jul 2025 18:52:33 +0200
Subject: [PATCH 0901/1338] testing: improving
 CountSinglyLinkedListRecursionTest (#6413)

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../CountSinglyLinkedListRecursionTest.java   | 80 ++++++++++++++-----
 1 file changed, 62 insertions(+), 18 deletions(-)

diff --git a/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java b/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java
index 1d814d0c2f9f..3d3f62fc5132 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java
@@ -1,8 +1,10 @@
 package com.thealgorithms.datastructures.lists;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
 public class CountSinglyLinkedListRecursionTest {
@@ -15,70 +17,112 @@ public void setUp() {
     }
 
     @Test
+    @DisplayName("Count of an empty list should be 0")
     public void testCountEmptyList() {
-        // An empty list should have a count of 0
-        assertEquals(0, list.count(), "Count of an empty list should be 0.");
+        assertEquals(0, list.count());
     }
 
     @Test
+    @DisplayName("Count after inserting a single element should be 1")
     public void testCountSingleElementList() {
-        // Insert a single element and check the count
         list.insert(1);
-        assertEquals(1, list.count(), "Count of a single-element list should be 1.");
+        assertEquals(1, list.count());
     }
 
     @Test
+    @DisplayName("Count after inserting multiple distinct elements")
     public void testCountMultipleElements() {
-        // Insert multiple elements and check the count
         for (int i = 1; i <= 5; i++) {
             list.insert(i);
         }
-        assertEquals(5, list.count(), "Count of a list with 5 elements should be 5.");
+        assertEquals(5, list.count());
     }
 
     @Test
+    @DisplayName("Count should reflect total number of nodes with duplicate values")
     public void testCountWithDuplicateElements() {
-        // Insert duplicate elements and verify the count is correct
-        list.insert(1);
         list.insert(2);
         list.insert(2);
         list.insert(3);
         list.insert(3);
-        assertEquals(5, list.count(), "Count of a list with duplicate elements should match total node count.");
+        list.insert(1);
+        assertEquals(5, list.count());
     }
 
     @Test
+    @DisplayName("Count should return 0 after clearing the list")
     public void testCountAfterClearingList() {
         for (int i = 1; i <= 4; i++) {
             list.insert(i);
         }
-        list.clear(); // assuming you have a clear method; if not, skip this
-        assertEquals(0, list.count(), "Count after clearing the list should be 0.");
+        list.clear(); // assumed to exist
+        assertEquals(0, list.count());
     }
 
     @Test
+    @DisplayName("Count on a very large list should be accurate")
     public void testCountOnVeryLargeList() {
         int n = 1000;
         for (int i = 0; i < n; i++) {
             list.insert(i);
         }
-        assertEquals(n, list.count(), "Count should correctly return for large list sizes.");
+        assertEquals(n, list.count());
     }
 
     @Test
+    @DisplayName("Count should work correctly with negative values")
     public void testCountOnListWithNegativeNumbers() {
         list.insert(-1);
-        list.insert(-5);
-        list.insert(-10);
-        assertEquals(3, list.count(), "Count should correctly handle negative values.");
+        list.insert(-2);
+        list.insert(-3);
+        assertEquals(3, list.count());
     }
 
     @Test
+    @DisplayName("Calling count multiple times should return the same value if list is unchanged")
     public void testCountIsConsistentWithoutModification() {
         list.insert(1);
         list.insert(2);
-        int firstCount = list.count();
-        int secondCount = list.count();
-        assertEquals(firstCount, secondCount, "Repeated count calls should return consistent values.");
+        int count1 = list.count();
+        int count2 = list.count();
+        assertEquals(count1, count2);
+    }
+
+    @Test
+    @DisplayName("Count should reflect total even if all values are the same")
+    public void testCountAllSameValues() {
+        for (int i = 0; i < 5; i++) {
+            list.insert(42);
+        }
+        assertEquals(5, list.count());
+    }
+
+    @Test
+    @DisplayName("Count should remain correct after multiple interleaved insert and count operations")
+    public void testCountAfterEachInsert() {
+        assertEquals(0, list.count());
+        list.insert(1);
+        assertEquals(1, list.count());
+        list.insert(2);
+        assertEquals(2, list.count());
+        list.insert(3);
+        assertEquals(3, list.count());
+    }
+
+    @Test
+    @DisplayName("List should not throw on edge count (0 nodes)")
+    public void testEdgeCaseNoElements() {
+        assertDoesNotThrow(() -> list.count());
+    }
+
+    @Test
+    @DisplayName("Should count accurately after inserting then removing all elements")
+    public void testCountAfterInsertAndClear() {
+        for (int i = 0; i < 10; i++) {
+            list.insert(i);
+        }
+        assertEquals(10, list.count());
+        list.clear();
+        assertEquals(0, list.count());
     }
 }

From cfd784105bbb47b172c0ba65b46bd30700953c9f Mon Sep 17 00:00:00 2001
From: Vishwajeet Deshmane <vishwajitdeshmane2004@gmail.com>
Date: Tue, 22 Jul 2025 22:47:24 +0530
Subject: [PATCH 0902/1338] Feat(Improved): Add 0/1 Knapsack Problem: Recursive
 and Tabulation (Bottom-Up DP) Implementations in Java along with their
 corresponding Tests  (#6425)

* feat: Add 0/1 Knapsack and its tabulation implementation with their corresponding tests

* feat: Add 0/1 Knapsack and its tabulation implementation with their corresponding tests

* feat: Add 0/1 Knapsack and its tabulation implementation with their corresponding tests

* Feat:add 0/1knapsack and 0/1knapsacktabulation along with their tests

* Feat:add 0/1knapsack and 0/1knapsacktabulation along with their tests

* Feat:add 0/1knapsack and 0/1knapsacktabulation along with their tests

---------

Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 .../dynamicprogramming/KnapsackZeroOne.java   | 53 +++++++++++++
 .../KnapsackZeroOneTabulation.java            | 69 ++++++++++++++++
 .../KnapsackZeroOneTabulationTest.java        | 78 +++++++++++++++++++
 .../KnapsackZeroOneTest.java                  | 68 ++++++++++++++++
 4 files changed, 268 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOne.java
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulation.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulationTest.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOne.java b/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOne.java
new file mode 100644
index 000000000000..abc1e321ca8f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOne.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.dynamicprogramming;
+
+/**
+ * The {@code KnapsackZeroOne} provides Recursive solution for the 0/1 Knapsack
+ * problem. Solves by exploring all combinations of items using recursion. No
+ * memoization or dynamic programming optimizations are applied.
+ *
+ * Time Complexity: O(2^n) — explores all subsets.
+ * Space Complexity: O(n) — due to recursive call stack.
+ *
+ * Problem Reference: https://en.wikipedia.org/wiki/Knapsack_problem
+ */
+public final class KnapsackZeroOne {
+
+    private KnapsackZeroOne() {
+        // Prevent instantiation
+    }
+
+    /**
+     * Solves the 0/1 Knapsack problem using recursion.
+     *
+     * @param values   the array containing values of the items
+     * @param weights  the array containing weights of the items
+     * @param capacity the total capacity of the knapsack
+     * @param n        the number of items
+     * @return the maximum total value achievable within the given weight limit
+     * @throws IllegalArgumentException if input arrays are null, empty, or
+     *     lengths mismatch
+     */
+    public static int compute(final int[] values, final int[] weights, final int capacity, final int n) {
+        if (values == null || weights == null) {
+            throw new IllegalArgumentException("Input arrays cannot be null.");
+        }
+        if (values.length != weights.length) {
+            throw new IllegalArgumentException("Value and weight arrays must be of the same length.");
+        }
+        if (capacity < 0 || n < 0) {
+            throw new IllegalArgumentException("Invalid input: arrays must be non-empty and capacity/n "
+                + "non-negative.");
+        }
+        if (n == 0 || capacity == 0 || values.length == 0) {
+            return 0;
+        }
+
+        if (weights[n - 1] <= capacity) {
+            final int include = values[n - 1] + compute(values, weights, capacity - weights[n - 1], n - 1);
+            final int exclude = compute(values, weights, capacity, n - 1);
+            return Math.max(include, exclude);
+        } else {
+            return compute(values, weights, capacity, n - 1);
+        }
+    }
+}
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulation.java b/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulation.java
new file mode 100644
index 000000000000..c560efc61c71
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulation.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.dynamicprogramming;
+
+/**
+ * Tabulation (Bottom-Up) Solution for 0-1 Knapsack Problem.
+ * This method uses dynamic programming to build up a solution iteratively,
+ * filling a 2-D array where each entry dp[i][w] represents the maximum value
+ * achievable with the first i items and a knapsack capacity of w.
+ *
+ * The tabulation approach is efficient because it avoids redundant calculations
+ * by solving all subproblems in advance and storing their results, ensuring
+ * each subproblem is solved only once. This is a key technique in dynamic programming,
+ * making it possible to solve problems that would otherwise be infeasible due to
+ * exponential time complexity in naive recursive solutions.
+ *
+ * Time Complexity: O(n * W), where n is the number of items and W is the knapsack capacity.
+ * Space Complexity: O(n * W) for the DP table.
+ *
+ * For more information, see:
+ * https://en.wikipedia.org/wiki/Knapsack_problem#Dynamic_programming
+ */
+public final class KnapsackZeroOneTabulation {
+
+    private KnapsackZeroOneTabulation() {
+        // Prevent instantiation
+    }
+
+    /**
+     * Solves the 0-1 Knapsack problem using the bottom-up tabulation technique.
+     * @param values the values of the items
+     * @param weights the weights of the items
+     * @param capacity the total capacity of the knapsack
+     * @param itemCount the number of items
+     * @return the maximum value that can be put in the knapsack
+     * @throws IllegalArgumentException if input arrays are null, of different lengths,or if capacity or itemCount is invalid
+     */
+    public static int compute(final int[] values, final int[] weights, final int capacity, final int itemCount) {
+        if (values == null || weights == null) {
+            throw new IllegalArgumentException("Values and weights arrays must not be null.");
+        }
+        if (values.length != weights.length) {
+            throw new IllegalArgumentException("Values and weights arrays must be non-null and of same length.");
+        }
+        if (capacity < 0) {
+            throw new IllegalArgumentException("Capacity must not be negative.");
+        }
+        if (itemCount < 0 || itemCount > values.length) {
+            throw new IllegalArgumentException("Item count must be between 0 and the length of the values array.");
+        }
+
+        final int[][] dp = new int[itemCount + 1][capacity + 1];
+
+        for (int i = 1; i <= itemCount; i++) {
+            final int currentValue = values[i - 1];
+            final int currentWeight = weights[i - 1];
+
+            for (int w = 1; w <= capacity; w++) {
+                if (currentWeight <= w) {
+                    final int includeItem = currentValue + dp[i - 1][w - currentWeight];
+                    final int excludeItem = dp[i - 1][w];
+                    dp[i][w] = Math.max(includeItem, excludeItem);
+                } else {
+                    dp[i][w] = dp[i - 1][w];
+                }
+            }
+        }
+
+        return dp[itemCount][capacity];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulationTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulationTest.java
new file mode 100644
index 000000000000..6c61ad2130e3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulationTest.java
@@ -0,0 +1,78 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class KnapsackZeroOneTabulationTest {
+
+    @Test
+    public void basicCheck() {
+        int[] values = {60, 100, 120};
+        int[] weights = {10, 20, 30};
+        int capacity = 50;
+        int itemCount = values.length;
+
+        int expected = 220; // Best choice: item 1 (100) and item 2 (120)
+        int result = KnapsackZeroOneTabulation.compute(values, weights, capacity, itemCount);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void emptyKnapsack() {
+        int[] values = {};
+        int[] weights = {};
+        int capacity = 50;
+        int itemCount = 0;
+
+        assertEquals(0, KnapsackZeroOneTabulation.compute(values, weights, capacity, itemCount));
+    }
+
+    @Test
+    public void zeroCapacity() {
+        int[] values = {60, 100, 120};
+        int[] weights = {10, 20, 30};
+        int capacity = 0;
+        int itemCount = values.length;
+
+        assertEquals(0, KnapsackZeroOneTabulation.compute(values, weights, capacity, itemCount));
+    }
+
+    @Test
+    public void negativeCapacity() {
+        int[] values = {10, 20, 30};
+        int[] weights = {1, 1, 1};
+        int capacity = -10;
+        int itemCount = values.length;
+
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOneTabulation.compute(values, weights, capacity, itemCount));
+        assertEquals("Capacity must not be negative.", exception.getMessage());
+    }
+
+    @Test
+    public void mismatchedLengths() {
+        int[] values = {60, 100}; // Only 2 values
+        int[] weights = {10, 20, 30}; // 3 weights
+        int capacity = 50;
+        int itemCount = 2; // Matches `values.length`
+
+        // You could either expect 0 or throw an IllegalArgumentException in your compute function
+        assertThrows(IllegalArgumentException.class, () -> { KnapsackZeroOneTabulation.compute(values, weights, capacity, itemCount); });
+    }
+
+    @Test
+    public void nullInputs() {
+        int[] weights = {1, 2, 3};
+        int capacity = 10;
+        int itemCount = 3;
+
+        IllegalArgumentException exception1 = assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOneTabulation.compute(null, weights, capacity, itemCount));
+        assertEquals("Values and weights arrays must not be null.", exception1.getMessage());
+
+        int[] values = {1, 2, 3};
+
+        IllegalArgumentException exception2 = assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOneTabulation.compute(values, null, capacity, itemCount));
+        assertEquals("Values and weights arrays must not be null.", exception2.getMessage());
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTest.java
new file mode 100644
index 000000000000..0ca2b91fc273
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTest.java
@@ -0,0 +1,68 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class KnapsackZeroOneTest {
+
+    @Test
+    void basicCheck() {
+        int[] values = {60, 100, 120};
+        int[] weights = {10, 20, 30};
+        int capacity = 50;
+        int expected = 220;
+
+        int result = KnapsackZeroOne.compute(values, weights, capacity, values.length);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void zeroCapacity() {
+        int[] values = {10, 20, 30};
+        int[] weights = {1, 1, 1};
+        int capacity = 0;
+
+        int result = KnapsackZeroOne.compute(values, weights, capacity, values.length);
+        assertEquals(0, result);
+    }
+
+    @Test
+    void zeroItems() {
+        int[] values = {};
+        int[] weights = {};
+        int capacity = 10;
+
+        int result = KnapsackZeroOne.compute(values, weights, capacity, 0);
+        assertEquals(0, result);
+    }
+
+    @Test
+    void weightsExceedingCapacity() {
+        int[] values = {10, 20};
+        int[] weights = {100, 200};
+        int capacity = 50;
+
+        int result = KnapsackZeroOne.compute(values, weights, capacity, values.length);
+        assertEquals(0, result);
+    }
+
+    @Test
+    void throwsOnNullArrays() {
+        assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOne.compute(null, new int[] {1}, 10, 1));
+        assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOne.compute(new int[] {1}, null, 10, 1));
+    }
+
+    @Test
+    void throwsOnMismatchedArrayLengths() {
+        assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOne.compute(new int[] {10, 20}, new int[] {5}, 15, 2));
+    }
+
+    @Test
+    void throwsOnNegativeInputs() {
+        assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOne.compute(new int[] {10}, new int[] {5}, -1, 1));
+
+        assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOne.compute(new int[] {10}, new int[] {5}, 5, -1));
+    }
+}

From ceead5eccd62b5e08e95bd838d731f08b685fdcb Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Tue, 22 Jul 2025 19:22:08 +0200
Subject: [PATCH 0903/1338] testing: refactor to ParameterizedTest
 `PrefixEvaluatorTest` (#6415)

testing: refactor to ParameterizedTest PrefixEvaluatorTest

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../stacks/PrefixEvaluatorTest.java            | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java b/src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java
index e2faa61955b3..ba67163fd49e 100644
--- a/src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java
+++ b/src/test/java/com/thealgorithms/stacks/PrefixEvaluatorTest.java
@@ -4,24 +4,28 @@
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.EmptyStackException;
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class PrefixEvaluatorTest {
 
-    @Test
-    public void testValidExpressions() {
-        assertEquals(10, PrefixEvaluator.evaluatePrefix("+ * 2 3 4"));
-        assertEquals(5, PrefixEvaluator.evaluatePrefix("- + 7 3 5"));
-        assertEquals(6, PrefixEvaluator.evaluatePrefix("/ * 3 2 1"));
+    @ParameterizedTest(name = "Expression: \"{0}\" → Result: {1}")
+    @CsvSource({"'+ * 2 3 4', 10", "'- + 7 3 5', 5", "'/ * 3 2 1', 6"})
+    void testValidExpressions(String expression, int expected) {
+        assertEquals(expected, PrefixEvaluator.evaluatePrefix(expression));
     }
 
     @Test
-    public void testInvalidExpression() {
+    @DisplayName("Should throw EmptyStackException for incomplete expression")
+    void testInvalidExpression() {
         assertThrows(EmptyStackException.class, () -> PrefixEvaluator.evaluatePrefix("+ 3"));
     }
 
     @Test
-    public void testMoreThanOneStackSizeAfterEvaluation() {
+    @DisplayName("Should throw IllegalArgumentException if stack not reduced to one result")
+    void testMoreThanOneStackSizeAfterEvaluation() {
         assertThrows(IllegalArgumentException.class, () -> PrefixEvaluator.evaluatePrefix("+ 3 4 5"));
     }
 }

From 7c2af29d295adf225359326fb75b4e56dd34286f Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Tue, 22 Jul 2025 19:25:46 +0200
Subject: [PATCH 0904/1338] Update DIRECTORY.md (#6431)

Co-authored-by: alxkm <alxkm@users.noreply.github.com>
---
 DIRECTORY.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index c52952edada4..9067f17ebc2d 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -304,6 +304,8 @@
           - 📄 [KadaneAlgorithm](src/main/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithm.java)
           - 📄 [Knapsack](src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java)
           - 📄 [KnapsackMemoization](src/main/java/com/thealgorithms/dynamicprogramming/KnapsackMemoization.java)
+          - 📄 [KnapsackZeroOne](src/main/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOne.java)
+          - 📄 [KnapsackZeroOneTabulation](src/main/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulation.java)
           - 📄 [LevenshteinDistance](src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java)
           - 📄 [LongestAlternatingSubsequence](src/main/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequence.java)
           - 📄 [LongestArithmeticSubsequence](src/main/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequence.java)
@@ -1009,6 +1011,8 @@
           - 📄 [KadaneAlgorithmTest](src/test/java/com/thealgorithms/dynamicprogramming/KadaneAlgorithmTest.java)
           - 📄 [KnapsackMemoizationTest](src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
           - 📄 [KnapsackTest](src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
+          - 📄 [KnapsackZeroOneTabulationTest](src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulationTest.java)
+          - 📄 [KnapsackZeroOneTest](src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTest.java)
           - 📄 [LevenshteinDistanceTests](src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
           - 📄 [LongestAlternatingSubsequenceTest](src/test/java/com/thealgorithms/dynamicprogramming/LongestAlternatingSubsequenceTest.java)
           - 📄 [LongestArithmeticSubsequenceTest](src/test/java/com/thealgorithms/dynamicprogramming/LongestArithmeticSubsequenceTest.java)

From 3304cf2e58ff2e155dcfda9f465f2eb06e02c136 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Tue, 22 Jul 2025 19:33:55 +0200
Subject: [PATCH 0905/1338] testing: improve `QueueByTwoStacksTest` (#6416)

testing: improve QueueByTwoStacksTest
---
 .../queues/QueueByTwoStacksTest.java          | 86 +++++++++++++++++--
 1 file changed, 77 insertions(+), 9 deletions(-)

diff --git a/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java b/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java
index 87f136a84631..491cb7634302 100644
--- a/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java
@@ -33,19 +33,19 @@ public void testDequeue() {
         queue.put(10);
         queue.put(20);
         queue.put(30);
-        assertEquals(10, queue.get()); // First item out
-        assertEquals(20, queue.get()); // Second item out
-        assertEquals(30, queue.get()); // Third item out
+        assertEquals(10, queue.get());
+        assertEquals(20, queue.get());
+        assertEquals(30, queue.get());
     }
 
     @Test
     public void testInterleavedOperations() {
         queue.put(10);
         queue.put(20);
-        assertEquals(10, queue.get()); // Dequeue first item
+        assertEquals(10, queue.get());
         queue.put(30);
-        assertEquals(20, queue.get()); // Dequeue second item
-        assertEquals(30, queue.get()); // Dequeue third item
+        assertEquals(20, queue.get());
+        assertEquals(30, queue.get());
     }
 
     @Test
@@ -62,8 +62,76 @@ public void testQueueSize() {
 
     @Test
     public void testEmptyQueueException() {
-        assertThrows(NoSuchElementException.class, () -> {
-            queue.get(); // Attempting to dequeue from empty queue
-        });
+        assertThrows(NoSuchElementException.class, () -> queue.get());
+    }
+
+    @Test
+    public void testDequeueAllElements() {
+        for (int i = 1; i <= 5; i++) {
+            queue.put(i);
+        }
+        for (int i = 1; i <= 5; i++) {
+            assertEquals(i, queue.get());
+        }
+        assertEquals(0, queue.size());
+    }
+
+    @Test
+    public void testLargeNumberOfOperations() {
+        int n = 1000;
+        for (int i = 0; i < n; i++) {
+            queue.put(i);
+        }
+        for (int i = 0; i < n; i++) {
+            assertEquals(i, queue.get());
+        }
+        assertEquals(0, queue.size());
+    }
+
+    @Test
+    public void testRefillDuringDequeue() {
+        queue.put(1);
+        queue.put(2);
+        assertEquals(1, queue.get());
+        queue.put(3);
+        queue.put(4);
+        assertEquals(2, queue.get());
+        assertEquals(3, queue.get());
+        assertEquals(4, queue.get());
+    }
+
+    @Test
+    public void testAlternatingPutAndGet() {
+        queue.put(1);
+        assertEquals(1, queue.get());
+        queue.put(2);
+        queue.put(3);
+        assertEquals(2, queue.get());
+        queue.put(4);
+        assertEquals(3, queue.get());
+        assertEquals(4, queue.get());
+    }
+
+    @Test
+    public void testSizeStability() {
+        queue.put(100);
+        int size1 = queue.size();
+        int size2 = queue.size();
+        assertEquals(size1, size2);
+    }
+
+    @Test
+    public void testMultipleEmptyDequeues() {
+        assertThrows(NoSuchElementException.class, () -> queue.get());
+        assertThrows(NoSuchElementException.class, () -> queue.get());
+    }
+
+    @Test
+    public void testQueueWithStrings() {
+        QueueByTwoStacks<String> stringQueue = new QueueByTwoStacks<>();
+        stringQueue.put("a");
+        stringQueue.put("b");
+        assertEquals("a", stringQueue.get());
+        assertEquals("b", stringQueue.get());
     }
 }

From bcfb3f22e6f9b986c3bfdcfc26e1676c6f3a767a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 22 Jul 2025 23:39:53 +0200
Subject: [PATCH 0906/1338] chore(deps): bump org.junit:junit-bom from 5.13.3
 to 5.13.4 (#6434)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 5.13.3 to 5.13.4.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r5.13.3...r5.13.4)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 5.13.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index f18462bec8fb..eff6b935e0fc 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.13.3</version>
+                <version>5.13.4</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 073b6f15a8ec177a2d95f69330985d5a0cc05611 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Wed, 23 Jul 2025 07:44:38 +0200
Subject: [PATCH 0907/1338] testing: improve `CircularBufferTest` (#6418)

* testing: improve CircularBufferTest

* style: redundant whitespace

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../buffers/CircularBufferTest.java           | 152 +++++++++++++++++-
 1 file changed, 148 insertions(+), 4 deletions(-)

diff --git a/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java b/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
index b115fc187b1a..69af422e7175 100644
--- a/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/buffers/CircularBufferTest.java
@@ -2,7 +2,6 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
-import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
@@ -68,11 +67,11 @@ void testFullBuffer() {
 
     @Test
     void testIllegalArguments() {
-        assertThrows(IllegalArgumentException.class, () -> new CircularBuffer<>(0));
-        assertThrows(IllegalArgumentException.class, () -> new CircularBuffer<>(-1));
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalArgumentException.class, () -> new CircularBuffer<>(0));
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalArgumentException.class, () -> new CircularBuffer<>(-1));
 
         CircularBuffer<String> buffer = new CircularBuffer<>(1);
-        assertThrows(IllegalArgumentException.class, () -> buffer.put(null));
+        org.junit.jupiter.api.Assertions.assertThrows(IllegalArgumentException.class, () -> buffer.put(null));
     }
 
     @Test
@@ -85,4 +84,149 @@ void testLargeBuffer() {
         buffer.put(1000); // This should overwrite 0
         assertEquals(1, buffer.get());
     }
+
+    @Test
+    void testPutAfterGet() {
+        CircularBuffer<Integer> buffer = new CircularBuffer<>(2);
+        buffer.put(10);
+        buffer.put(20);
+        assertEquals(10, buffer.get());
+        buffer.put(30);
+        assertEquals(20, buffer.get());
+        assertEquals(30, buffer.get());
+        assertNull(buffer.get());
+    }
+
+    @Test
+    void testMultipleWrapArounds() {
+        CircularBuffer<Integer> buffer = new CircularBuffer<>(3);
+        for (int i = 1; i <= 6; i++) {
+            buffer.put(i);
+            buffer.get(); // add and immediately remove
+        }
+        assertTrue(buffer.isEmpty());
+        assertNull(buffer.get());
+    }
+
+    @Test
+    void testOverwriteMultipleTimes() {
+        CircularBuffer<String> buffer = new CircularBuffer<>(2);
+        buffer.put("X");
+        buffer.put("Y");
+        buffer.put("Z"); // overwrites "X"
+        buffer.put("W"); // overwrites "Y"
+        assertEquals("Z", buffer.get());
+        assertEquals("W", buffer.get());
+        assertNull(buffer.get());
+    }
+
+    @Test
+    void testIsEmptyAndIsFullTransitions() {
+        CircularBuffer<Integer> buffer = new CircularBuffer<>(2);
+        assertTrue(buffer.isEmpty());
+        org.junit.jupiter.api.Assertions.assertFalse(buffer.isFull());
+
+        buffer.put(1);
+        org.junit.jupiter.api.Assertions.assertFalse(buffer.isEmpty());
+        org.junit.jupiter.api.Assertions.assertFalse(buffer.isFull());
+
+        buffer.put(2);
+        assertTrue(buffer.isFull());
+
+        buffer.get();
+        org.junit.jupiter.api.Assertions.assertFalse(buffer.isFull());
+
+        buffer.get();
+        assertTrue(buffer.isEmpty());
+    }
+
+    @Test
+    void testInterleavedPutAndGet() {
+        CircularBuffer<String> buffer = new CircularBuffer<>(3);
+        buffer.put("A");
+        buffer.put("B");
+        assertEquals("A", buffer.get());
+        buffer.put("C");
+        assertEquals("B", buffer.get());
+        assertEquals("C", buffer.get());
+        assertNull(buffer.get());
+    }
+
+    @Test
+    void testRepeatedNullInsertionThrows() {
+        CircularBuffer<Object> buffer = new CircularBuffer<>(5);
+        for (int i = 0; i < 3; i++) {
+            int finalI = i;
+            org.junit.jupiter.api.Assertions.assertThrows(IllegalArgumentException.class, () -> buffer.put(null), "Iteration: " + finalI);
+        }
+    }
+    @Test
+    void testFillThenEmptyThenReuseBuffer() {
+        CircularBuffer<Integer> buffer = new CircularBuffer<>(3);
+
+        buffer.put(1);
+        buffer.put(2);
+        buffer.put(3);
+        assertTrue(buffer.isFull());
+
+        assertEquals(1, buffer.get());
+        assertEquals(2, buffer.get());
+        assertEquals(3, buffer.get());
+
+        assertTrue(buffer.isEmpty());
+
+        buffer.put(4);
+        buffer.put(5);
+        assertEquals(4, buffer.get());
+        assertEquals(5, buffer.get());
+        assertTrue(buffer.isEmpty());
+    }
+
+    @Test
+    void testPutReturnsTrueOnlyIfPreviouslyEmpty() {
+        CircularBuffer<String> buffer = new CircularBuffer<>(2);
+
+        assertTrue(buffer.put("one")); // was empty
+        org.junit.jupiter.api.Assertions.assertFalse(buffer.put("two")); // not empty
+        org.junit.jupiter.api.Assertions.assertFalse(buffer.put("three")); // overwrite
+    }
+
+    @Test
+    void testOverwriteAndGetAllElementsCorrectly() {
+        CircularBuffer<Integer> buffer = new CircularBuffer<>(3);
+
+        buffer.put(1);
+        buffer.put(2);
+        buffer.put(3);
+        buffer.put(4); // Overwrites 1
+        buffer.put(5); // Overwrites 2
+
+        assertEquals(3, buffer.get());
+        assertEquals(4, buffer.get());
+        assertEquals(5, buffer.get());
+        assertNull(buffer.get());
+    }
+
+    @Test
+    void testBufferWithOneElementCapacity() {
+        CircularBuffer<String> buffer = new CircularBuffer<>(1);
+
+        assertTrue(buffer.put("first"));
+        assertEquals("first", buffer.get());
+        assertNull(buffer.get());
+
+        assertTrue(buffer.put("second"));
+        assertEquals("second", buffer.get());
+    }
+
+    @Test
+    void testPointerWraparoundWithExactMultipleOfCapacity() {
+        CircularBuffer<Integer> buffer = new CircularBuffer<>(3);
+        for (int i = 0; i < 6; i++) {
+            buffer.put(i);
+            buffer.get(); // keep buffer size at 0
+        }
+        assertTrue(buffer.isEmpty());
+        assertNull(buffer.get());
+    }
 }

From 7e3fbae1a4ff17ba93566d431722f4a4ac4af27c Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Wed, 23 Jul 2025 17:09:18 +0200
Subject: [PATCH 0908/1338] testing: improve `SortStackTest` (#6422)

testing: improve SortStackTest

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../thealgorithms/stacks/SortStackTest.java   | 183 ++++++++++++++++++
 1 file changed, 183 insertions(+)

diff --git a/src/test/java/com/thealgorithms/stacks/SortStackTest.java b/src/test/java/com/thealgorithms/stacks/SortStackTest.java
index b9f2f1b6f106..9747af5337e8 100644
--- a/src/test/java/com/thealgorithms/stacks/SortStackTest.java
+++ b/src/test/java/com/thealgorithms/stacks/SortStackTest.java
@@ -74,4 +74,187 @@ public void testSortWithDuplicateElements() {
         assertEquals(2, (int) stack.pop());
         assertEquals(1, (int) stack.pop());
     }
+
+    @Test
+    public void testSortReverseSortedStack() {
+        // Test worst case scenario - completely reverse sorted
+        stack.push(5);
+        stack.push(4);
+        stack.push(3);
+        stack.push(2);
+        stack.push(1);
+        SortStack.sortStack(stack);
+
+        assertEquals(5, stack.size());
+        assertEquals(5, (int) stack.pop());
+        assertEquals(4, (int) stack.pop());
+        assertEquals(3, (int) stack.pop());
+        assertEquals(2, (int) stack.pop());
+        assertEquals(1, (int) stack.pop());
+    }
+
+    @Test
+    public void testSortWithAllSameElements() {
+        // Test stack with all identical elements
+        stack.push(7);
+        stack.push(7);
+        stack.push(7);
+        stack.push(7);
+        SortStack.sortStack(stack);
+
+        assertEquals(4, stack.size());
+        assertEquals(7, (int) stack.pop());
+        assertEquals(7, (int) stack.pop());
+        assertEquals(7, (int) stack.pop());
+        assertEquals(7, (int) stack.pop());
+    }
+
+    @Test
+    public void testSortWithNegativeNumbers() {
+        // Test with negative numbers
+        stack.push(-3);
+        stack.push(1);
+        stack.push(-5);
+        stack.push(2);
+        stack.push(-1);
+        SortStack.sortStack(stack);
+
+        assertEquals(5, stack.size());
+        assertEquals(2, (int) stack.pop());
+        assertEquals(1, (int) stack.pop());
+        assertEquals(-1, (int) stack.pop());
+        assertEquals(-3, (int) stack.pop());
+        assertEquals(-5, (int) stack.pop());
+    }
+
+    @Test
+    public void testSortWithAllNegativeNumbers() {
+        // Test with only negative numbers
+        stack.push(-10);
+        stack.push(-5);
+        stack.push(-15);
+        stack.push(-1);
+        SortStack.sortStack(stack);
+
+        assertEquals(4, stack.size());
+        assertEquals(-1, (int) stack.pop());
+        assertEquals(-5, (int) stack.pop());
+        assertEquals(-10, (int) stack.pop());
+        assertEquals(-15, (int) stack.pop());
+    }
+
+    @Test
+    public void testSortWithZero() {
+        // Test with zero included
+        stack.push(3);
+        stack.push(0);
+        stack.push(-2);
+        stack.push(1);
+        SortStack.sortStack(stack);
+
+        assertEquals(4, stack.size());
+        assertEquals(3, (int) stack.pop());
+        assertEquals(1, (int) stack.pop());
+        assertEquals(0, (int) stack.pop());
+        assertEquals(-2, (int) stack.pop());
+    }
+
+    @Test
+    public void testSortLargerStack() {
+        // Test with a larger number of elements
+        int[] values = {15, 3, 9, 1, 12, 6, 18, 4, 11, 8};
+        for (int value : values) {
+            stack.push(value);
+        }
+
+        SortStack.sortStack(stack);
+
+        assertEquals(10, stack.size());
+
+        // Verify sorted order (largest to smallest when popping)
+        int[] expectedOrder = {18, 15, 12, 11, 9, 8, 6, 4, 3, 1};
+        for (int expected : expectedOrder) {
+            assertEquals(expected, (int) stack.pop());
+        }
+    }
+
+    @Test
+    public void testSortTwoElements() {
+        // Test edge case with exactly two elements
+        stack.push(5);
+        stack.push(2);
+        SortStack.sortStack(stack);
+
+        assertEquals(2, stack.size());
+        assertEquals(5, (int) stack.pop());
+        assertEquals(2, (int) stack.pop());
+    }
+
+    @Test
+    public void testSortTwoElementsAlreadySorted() {
+        // Test two elements already in correct order
+        stack.push(2);
+        stack.push(5);
+        SortStack.sortStack(stack);
+
+        assertEquals(2, stack.size());
+        assertEquals(5, (int) stack.pop());
+        assertEquals(2, (int) stack.pop());
+    }
+
+    @Test
+    public void testSortStackWithMinAndMaxValues() {
+        // Test with Integer.MAX_VALUE and Integer.MIN_VALUE
+        stack.push(0);
+        stack.push(Integer.MAX_VALUE);
+        stack.push(Integer.MIN_VALUE);
+        stack.push(100);
+        SortStack.sortStack(stack);
+
+        assertEquals(4, stack.size());
+        assertEquals(Integer.MAX_VALUE, (int) stack.pop());
+        assertEquals(100, (int) stack.pop());
+        assertEquals(0, (int) stack.pop());
+        assertEquals(Integer.MIN_VALUE, (int) stack.pop());
+    }
+
+    @Test
+    public void testSortWithManyDuplicates() {
+        // Test with multiple sets of duplicates
+        stack.push(3);
+        stack.push(1);
+        stack.push(3);
+        stack.push(1);
+        stack.push(2);
+        stack.push(2);
+        stack.push(3);
+        SortStack.sortStack(stack);
+
+        assertEquals(7, stack.size());
+        assertEquals(3, (int) stack.pop());
+        assertEquals(3, (int) stack.pop());
+        assertEquals(3, (int) stack.pop());
+        assertEquals(2, (int) stack.pop());
+        assertEquals(2, (int) stack.pop());
+        assertEquals(1, (int) stack.pop());
+        assertEquals(1, (int) stack.pop());
+    }
+
+    @Test
+    public void testOriginalStackIsModified() {
+        // Verify that the original stack is modified, not a copy
+        Stack<Integer> originalReference = stack;
+        stack.push(3);
+        stack.push(1);
+        stack.push(2);
+
+        SortStack.sortStack(stack);
+
+        // Verify it's the same object reference
+        assertTrue(stack == originalReference);
+        assertEquals(3, stack.size());
+        assertEquals(3, (int) stack.pop());
+        assertEquals(2, (int) stack.pop());
+        assertEquals(1, (int) stack.pop());
+    }
 }

From 699271665d4935d7f45d2b18f878fc4e8d55efb3 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Wed, 23 Jul 2025 22:02:52 +0200
Subject: [PATCH 0909/1338] testing: improve `QueueTest` (#6423)

* testing: improve QueueTest

* testing: fix test
---
 .../datastructures/queues/QueueTest.java      | 200 ++++++++++++++++++
 1 file changed, 200 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java b/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java
index 9a4f50d5e216..86ef940beab6 100644
--- a/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java
@@ -124,4 +124,204 @@ void testQueueCapacityException() {
         Assertions.assertThrows(IllegalArgumentException.class, () -> new Queue<>(0));
         Assertions.assertThrows(IllegalArgumentException.class, () -> new Queue<>(-5));
     }
+
+    @Test
+    void testCircularBehavior() {
+        // Test that queue behaves correctly after multiple insert/remove cycles
+        queue.insert(1);
+        queue.insert(2);
+        queue.insert(3);
+
+        // Remove all elements
+        queue.remove(); // removes 1
+        queue.remove(); // removes 2
+        queue.remove(); // removes 3
+
+        // Add elements again to test circular behavior
+        queue.insert(4);
+        queue.insert(5);
+        queue.insert(6);
+
+        Assertions.assertEquals(4, queue.peekFront());
+        Assertions.assertEquals(6, queue.peekRear());
+        Assertions.assertEquals(3, queue.getSize());
+        Assertions.assertTrue(queue.isFull());
+    }
+
+    @Test
+    void testMixedInsertRemoveOperations() {
+        // Test interleaved insert and remove operations
+        queue.insert(1);
+        queue.insert(2);
+
+        Assertions.assertEquals(1, queue.remove());
+        queue.insert(3);
+        queue.insert(4);
+
+        Assertions.assertEquals(2, queue.remove());
+        Assertions.assertEquals(3, queue.remove());
+
+        queue.insert(5);
+        queue.insert(6);
+
+        Assertions.assertEquals(4, queue.peekFront());
+        Assertions.assertEquals(6, queue.peekRear());
+        Assertions.assertEquals(3, queue.getSize());
+    }
+
+    @Test
+    void testSingleElementOperations() {
+        // Test operations with single element
+        queue.insert(42);
+
+        Assertions.assertEquals(42, queue.peekFront());
+        Assertions.assertEquals(42, queue.peekRear());
+        Assertions.assertEquals(1, queue.getSize());
+        Assertions.assertFalse(queue.isEmpty());
+        Assertions.assertFalse(queue.isFull());
+
+        Assertions.assertEquals(42, queue.remove());
+        Assertions.assertTrue(queue.isEmpty());
+        Assertions.assertEquals(0, queue.getSize());
+    }
+
+    @Test
+    void testNullValueHandling() {
+        // Test queue with null values (if supported)
+        Queue<String> stringQueue = new Queue<>(3);
+
+        Assertions.assertTrue(stringQueue.insert(null));
+        Assertions.assertTrue(stringQueue.insert("test"));
+        Assertions.assertTrue(stringQueue.insert(null));
+
+        Assertions.assertNull(stringQueue.peekFront());
+        Assertions.assertNull(stringQueue.peekRear());
+        Assertions.assertEquals(3, stringQueue.getSize());
+
+        Assertions.assertNull(stringQueue.remove());
+        Assertions.assertEquals("test", stringQueue.peekFront());
+    }
+
+    @Test
+    void testStringDataType() {
+        // Test queue with String data type
+        Queue<String> stringQueue = new Queue<>(2);
+        stringQueue.insert("first");
+        stringQueue.insert("second");
+
+        Assertions.assertEquals("first", stringQueue.peekFront());
+        Assertions.assertEquals("second", stringQueue.peekRear());
+    }
+
+    @Test
+    void testLargerCapacityQueue() {
+        // Test queue with larger capacity
+        Queue<Integer> largeQueue = new Queue<>(10);
+
+        // Fill the queue
+        for (int i = 1; i <= 10; i++) {
+            Assertions.assertTrue(largeQueue.insert(i));
+        }
+
+        Assertions.assertTrue(largeQueue.isFull());
+        Assertions.assertFalse(largeQueue.insert(11));
+
+        // Remove half the elements
+        for (int i = 1; i <= 5; i++) {
+            Assertions.assertEquals(i, largeQueue.remove());
+        }
+
+        Assertions.assertEquals(6, largeQueue.peekFront());
+        Assertions.assertEquals(10, largeQueue.peekRear());
+        Assertions.assertEquals(5, largeQueue.getSize());
+    }
+
+    @Test
+    void testQueueCapacityOne() {
+        // Test queue with capacity of 1
+        Queue<Integer> singleQueue = new Queue<>(1);
+
+        Assertions.assertTrue(singleQueue.isEmpty());
+        Assertions.assertFalse(singleQueue.isFull());
+
+        Assertions.assertTrue(singleQueue.insert(100));
+        Assertions.assertTrue(singleQueue.isFull());
+        Assertions.assertFalse(singleQueue.isEmpty());
+        Assertions.assertFalse(singleQueue.insert(200));
+
+        Assertions.assertEquals(100, singleQueue.peekFront());
+        Assertions.assertEquals(100, singleQueue.peekRear());
+
+        Assertions.assertEquals(100, singleQueue.remove());
+        Assertions.assertTrue(singleQueue.isEmpty());
+    }
+
+    @Test
+    void testQueueWraparoundIndexing() {
+        // Test that internal array indexing wraps around correctly
+        queue.insert(1);
+        queue.insert(2);
+        queue.insert(3); // Queue full
+
+        // Remove one element
+        queue.remove(); // removes 1
+
+        // Add another element (should wrap around)
+        queue.insert(4);
+
+        Assertions.assertEquals("[2, 3, 4]", queue.toString());
+        Assertions.assertEquals(2, queue.peekFront());
+        Assertions.assertEquals(4, queue.peekRear());
+
+        // Continue the pattern
+        queue.remove(); // removes 2
+        queue.insert(5);
+
+        Assertions.assertEquals(3, queue.peekFront());
+        Assertions.assertEquals(5, queue.peekRear());
+    }
+
+    @Test
+    void testQueueStateAfterMultipleCycles() {
+        // Test queue state after multiple complete fill/empty cycles
+        for (int cycle = 0; cycle < 3; cycle++) {
+            // Fill the queue
+            for (int i = 1; i <= 3; i++) {
+                queue.insert(i + cycle * 10);
+            }
+
+            // Verify state
+            Assertions.assertTrue(queue.isFull());
+            Assertions.assertEquals(3, queue.getSize());
+
+            // Empty the queue
+            for (int i = 1; i <= 3; i++) {
+                queue.remove();
+            }
+
+            // Verify empty state
+            Assertions.assertTrue(queue.isEmpty());
+            Assertions.assertEquals(0, queue.getSize());
+        }
+    }
+
+    @Test
+    void testQueueConsistencyAfterOperations() {
+        // Test that queue maintains consistency after various operations
+        queue.insert(10);
+        queue.insert(20);
+
+        int firstRemoved = queue.remove();
+        queue.insert(30);
+        queue.insert(40);
+
+        int secondRemoved = queue.remove();
+        queue.insert(50);
+
+        // Verify the order is maintained
+        Assertions.assertEquals(10, firstRemoved);
+        Assertions.assertEquals(20, secondRemoved);
+        Assertions.assertEquals(30, queue.peekFront());
+        Assertions.assertEquals(50, queue.peekRear());
+    }
 }

From ec7b654d0b74d0025796d5fcfd674e509d0c3afe Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Thu, 24 Jul 2025 11:42:33 +0200
Subject: [PATCH 0910/1338] testing: improve `StackArrayTest` (#6424)

testing: improve StackArrayTest
---
 .../datastructures/stacks/StackArrayTest.java | 58 +++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java
index 74de7ad6435a..392cdf2329fc 100644
--- a/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java
@@ -126,4 +126,62 @@ void testToString() {
         stack.push(3);
         Assertions.assertEquals("StackArray [1, 2, 3]", stack.toString());
     }
+
+    @Test
+    void testSingleElementOperations() {
+        // Test operations with a single element
+        stack.push(2);
+        Assertions.assertEquals(1, stack.size());
+        Assertions.assertFalse(stack.isEmpty());
+        Assertions.assertEquals(2, stack.peek());
+        Assertions.assertEquals(2, stack.pop());
+        Assertions.assertTrue(stack.isEmpty());
+    }
+
+    @Test
+    void testAlternatingPushPop() {
+        // Test alternating push and pop operations
+        stack.push(1);
+        Assertions.assertEquals(1, stack.pop());
+
+        stack.push(2);
+        stack.push(3);
+        Assertions.assertEquals(3, stack.pop());
+
+        stack.push(4);
+        Assertions.assertEquals(4, stack.pop());
+        Assertions.assertEquals(2, stack.pop());
+        Assertions.assertTrue(stack.isEmpty());
+    }
+
+    @Test
+    void testPushNullElements() {
+        // Test pushing null values
+        stack.push(null);
+        Assertions.assertEquals(1, stack.size());
+        Assertions.assertNull(stack.peek());
+        Assertions.assertNull(stack.pop());
+
+        // Mix null and non-null values
+        stack.push(1);
+        stack.push(null);
+        stack.push(2);
+
+        Assertions.assertEquals(2, stack.pop());
+        Assertions.assertNull(stack.pop());
+        Assertions.assertEquals(1, stack.pop());
+    }
+
+    @Test
+    void testWithDifferentDataTypes() {
+        // Test with String type
+        StackArray<String> stringStack = new StackArray<>(3);
+        stringStack.push("first");
+        stringStack.push("second");
+        stringStack.push("third");
+
+        Assertions.assertEquals("third", stringStack.pop());
+        Assertions.assertEquals("second", stringStack.peek());
+        Assertions.assertEquals(2, stringStack.size());
+    }
 }

From ac5849323e61adb547b0191fa857f8252704c75e Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Thu, 24 Jul 2025 20:34:31 +0200
Subject: [PATCH 0911/1338] testing: improve test coverage
 `CursorLinkedListTest` (#6428)

* testing: improve test coverage CursorLinkedListTest

* style: fix checkstyle formatting
---
 .../lists/CursorLinkedListTest.java           | 185 ++++++++++++++++++
 1 file changed, 185 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java
index bf5501826994..20bf24d79159 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java
@@ -109,4 +109,189 @@ void testMemoryLimitExceeded() {
             }
         });
     }
+
+    @Test
+    void testSingleElementOperations() {
+        // Test operations with just one element
+        list.append("Only");
+        assertEquals("Only", list.get(0));
+        assertEquals(0, list.indexOf("Only"));
+
+        list.remove("Only");
+        assertNull(list.get(0));
+        assertEquals(-1, list.indexOf("Only"));
+    }
+
+    @Test
+    void testDuplicateElements() {
+        // Test handling of duplicate elements
+        list.append("Duplicate");
+        list.append("Other");
+        list.append("Duplicate");
+
+        assertEquals(0, list.indexOf("Duplicate")); // Should return first occurrence
+        assertEquals("Duplicate", list.get(0));
+        assertEquals("Duplicate", list.get(2));
+
+        list.remove("Duplicate"); // Should remove first occurrence
+        assertEquals("Other", list.get(0));
+        assertEquals("Duplicate", list.get(1));
+    }
+
+    @Test
+    void testRemoveByIndexEdgeCases() {
+        list.append("First");
+        list.append("Second");
+        list.append("Third");
+
+        // Test removing invalid indices
+        list.removeByIndex(-1); // Should not crash
+        list.removeByIndex(10); // Should not crash
+
+        // Verify list unchanged
+        assertEquals("First", list.get(0));
+        assertEquals("Second", list.get(1));
+        assertEquals("Third", list.get(2));
+
+        // Test removing first element by index
+        list.removeByIndex(0);
+        assertEquals("Second", list.get(0));
+        assertEquals("Third", list.get(1));
+    }
+
+    @Test
+    void testRemoveByIndexLastElement() {
+        list.append("First");
+        list.append("Second");
+        list.append("Third");
+
+        // Remove last element by index
+        list.removeByIndex(2);
+        assertEquals("First", list.get(0));
+        assertEquals("Second", list.get(1));
+        assertNull(list.get(2));
+    }
+
+    @Test
+    void testConsecutiveOperations() {
+        // Test multiple consecutive operations
+        list.append("A");
+        list.append("B");
+        list.append("C");
+        list.append("D");
+
+        list.remove("B");
+        list.remove("D");
+
+        assertEquals("A", list.get(0));
+        assertEquals("C", list.get(1));
+        assertNull(list.get(2));
+
+        list.append("E");
+        assertEquals("E", list.get(2));
+    }
+
+    @Test
+    void testMemoryReclamation() {
+        // Test that removed elements free up memory space
+        for (int i = 0; i < 50; i++) {
+            list.append("Element" + i);
+        }
+
+        // Remove some elements
+        for (int i = 0; i < 25; i++) {
+            list.remove("Element" + i);
+        }
+
+        // Should be able to add more elements (testing memory reclamation)
+        for (int i = 100; i < 150; i++) {
+            list.append("New" + i);
+        }
+
+        // Verify some elements exist
+        assertEquals("Element25", list.get(0));
+        assertEquals("New100", list.get(25));
+    }
+
+    @Test
+    void testSpecialCharacters() {
+        // Test with strings containing special characters
+        list.append("Hello World!");
+        list.append("Test@123");
+        list.append("Special#$%");
+        list.append(""); // Empty string
+
+        assertEquals("Hello World!", list.get(0));
+        assertEquals("Test@123", list.get(1));
+        assertEquals("Special#$%", list.get(2));
+        assertEquals("", list.get(3));
+
+        assertEquals(3, list.indexOf(""));
+    }
+
+    @Test
+    void testLargeIndices() {
+        list.append("Test");
+
+        // Test very large indices
+        assertNull(list.get(Integer.MAX_VALUE));
+        assertNull(list.get(1000));
+    }
+
+    @Test
+    void testSequentialRemovalByIndex() {
+        list.append("A");
+        list.append("B");
+        list.append("C");
+        list.append("D");
+
+        // Remove elements sequentially by index
+        list.removeByIndex(1); // Remove "B"
+        assertEquals("A", list.get(0));
+        assertEquals("C", list.get(1));
+        assertEquals("D", list.get(2));
+
+        list.removeByIndex(1); // Remove "C"
+        assertEquals("A", list.get(0));
+        assertEquals("D", list.get(1));
+        assertNull(list.get(2));
+    }
+
+    @Test
+    void testAppendAfterRemoval() {
+        list.append("First");
+        list.append("Second");
+
+        list.remove("First");
+        list.append("Third");
+
+        assertEquals("Second", list.get(0));
+        assertEquals("Third", list.get(1));
+        assertEquals(1, list.indexOf("Third"));
+    }
+
+    @Test
+    void testPerformanceWithManyOperations() {
+        // Test with many mixed operations
+        for (int i = 0; i < 50; i++) {
+            list.append("Item" + i);
+        }
+
+        // Remove every other element
+        for (int i = 0; i < 50; i += 2) {
+            list.remove("Item" + i);
+        }
+
+        // Verify remaining elements
+        assertEquals("Item1", list.get(0));
+        assertEquals("Item3", list.get(1));
+        assertEquals("Item5", list.get(2));
+
+        // Add more elements
+        for (int i = 100; i < 110; i++) {
+            list.append("New" + i);
+        }
+
+        assertEquals("New100", list.get(25));
+    }
 }

From 4f16ad0b0ed2c392c255ca3d717d45fffc85e01d Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Thu, 24 Jul 2025 20:41:02 +0200
Subject: [PATCH 0912/1338] testing: improve test coverage `DequeTest` (#6429)

testing: improve test coverage DequeTest
---
 .../datastructures/queues/DequeTest.java      | 73 +++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java b/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java
index 34b1ea2e0277..ada314383c74 100644
--- a/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java
@@ -121,4 +121,77 @@ void testNullValues() {
         assertNull(deque.pollFirst());
         org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty());
     }
+
+    @Test
+    void testMultipleAddFirst() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addFirst(1);
+        deque.addFirst(2);
+        deque.addFirst(3);
+
+        assertEquals(3, deque.peekFirst(), "First element should be the last added to front");
+        assertEquals(1, deque.peekLast(), "Last element should be the first added to front");
+        assertEquals(3, deque.size(), "Size should reflect all additions");
+    }
+
+    @Test
+    void testMultipleAddLast() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addLast(1);
+        deque.addLast(2);
+        deque.addLast(3);
+
+        assertEquals(1, deque.peekFirst(), "First element should be the first added to back");
+        assertEquals(3, deque.peekLast(), "Last element should be the last added to back");
+        assertEquals(3, deque.size(), "Size should reflect all additions");
+    }
+
+    @Test
+    void testSingleElementOperations() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addFirst(1);
+
+        assertEquals(1, deque.peekFirst(), "Single element should be both first and last");
+        assertEquals(1, deque.peekLast(), "Single element should be both first and last");
+        assertEquals(1, deque.size());
+
+        assertEquals(1, deque.pollFirst(), "Should be able to poll single element from front");
+        org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty(), "Deque should be empty after polling single element");
+    }
+
+    @Test
+    void testSingleElementPollLast() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addLast(1);
+
+        assertEquals(1, deque.pollLast(), "Should be able to poll single element from back");
+        org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty(), "Deque should be empty after polling single element");
+    }
+
+    @Test
+    void testMixedNullAndValues() {
+        Deque<String> deque = new Deque<>();
+        deque.addFirst("first");
+        deque.addLast(null);
+        deque.addFirst(null);
+        deque.addLast("last");
+
+        assertEquals(4, deque.size(), "Should handle mixed null and non-null values");
+        assertNull(deque.pollFirst(), "Should poll null from front");
+        assertEquals("first", deque.pollFirst(), "Should poll non-null value");
+        assertNull(deque.pollLast().equals("last") ? null : deque.peekLast(), "Should handle null correctly");
+    }
+
+    @Test
+    void testSymmetricOperations() {
+        Deque<Integer> deque = new Deque<>();
+
+        // Test that addFirst/pollFirst and addLast/pollLast are symmetric
+        deque.addFirst(1);
+        deque.addLast(2);
+
+        assertEquals(1, deque.pollFirst(), "addFirst/pollFirst should be symmetric");
+        assertEquals(2, deque.pollLast(), "addLast/pollLast should be symmetric");
+        org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty(), "Deque should be empty after symmetric operations");
+    }
 }

From fc07cd806e6c006683a53c3272d4bd92435b12b8 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Thu, 24 Jul 2025 21:36:52 +0200
Subject: [PATCH 0913/1338] testing: improve test coverage
 `StackOfLinkedListTest` (#6430)

* testing: improve test coverage StackOfLinkedListTest

* testing: fix spotbugs
---
 .../stacks/StackOfLinkedListTest.java         | 100 ++++++++++++++++++
 1 file changed, 100 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java
index 58af66bc38f4..2dfe4c242e1c 100644
--- a/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/StackOfLinkedListTest.java
@@ -118,4 +118,104 @@ public void testSequentialPushAndPop() {
         }
         assertTrue(stack.isEmpty(), "Stack should be empty after popping all elements");
     }
+
+    @Test
+    public void testPushZeroAndNegativeValues() {
+        stack.push(0);
+        stack.push(-1);
+        stack.push(-1);
+
+        assertEquals(-1, stack.pop(), "Should handle negative values correctly");
+        assertEquals(-1, stack.pop(), "Should handle negative values correctly");
+        assertEquals(0, stack.pop(), "Should handle zero value correctly");
+    }
+
+    @Test
+    public void testPushDuplicateValues() {
+        stack.push(1);
+        stack.push(1);
+        stack.push(1);
+
+        assertEquals(3, stack.getSize(), "Should allow duplicate values");
+        assertEquals(1, stack.pop());
+        assertEquals(1, stack.pop());
+        assertEquals(1, stack.pop());
+    }
+
+    @Test
+    public void testPushAfterEmptyingStack() {
+        stack.push(1);
+        stack.push(2);
+        stack.pop();
+        stack.pop();
+
+        assertTrue(stack.isEmpty(), "Stack should be empty");
+
+        stack.push(10);
+        assertEquals(10, stack.peek(), "Should work correctly after emptying and refilling");
+        assertEquals(1, stack.getSize(), "Size should be correct after refilling");
+    }
+
+    @Test
+    public void testPeekDoesNotModifyStack() {
+        stack.push(1);
+
+        int firstPeek = stack.peek();
+        int secondPeek = stack.peek();
+        int thirdPeek = stack.peek();
+
+        assertEquals(firstPeek, secondPeek, "Multiple peeks should return same value");
+        assertEquals(secondPeek, thirdPeek, "Multiple peeks should return same value");
+        assertEquals(1, stack.getSize(), "Peek should not modify stack size");
+        assertEquals(1, stack.pop(), "Element should still be poppable after peeking");
+    }
+
+    @Test
+    public void testAlternatingPushAndPop() {
+        stack.push(1);
+        assertEquals(1, stack.pop());
+
+        stack.push(2);
+        stack.push(3);
+        assertEquals(3, stack.pop());
+
+        stack.push(4);
+        assertEquals(4, stack.pop());
+        assertEquals(2, stack.pop());
+
+        assertTrue(stack.isEmpty(), "Stack should be empty after alternating operations");
+    }
+
+    @Test
+    public void testToStringWithSingleElement() {
+        stack.push(42);
+        assertEquals("42", stack.toString(), "String representation with single element should not have arrows");
+    }
+
+    @Test
+    public void testStackIntegrity() {
+        // Test that internal state remains consistent
+        for (int i = 0; i < 10; i++) {
+            stack.push(i);
+            assertEquals(i + 1, stack.getSize(), "Size should be consistent during pushes");
+            assertEquals(i, stack.peek(), "Peek should return last pushed value");
+        }
+
+        for (int i = 9; i >= 0; i--) {
+            assertEquals(i, stack.peek(), "Peek should return correct value before pop");
+            assertEquals(i, stack.pop(), "Pop should return values in LIFO order");
+            assertEquals(i, stack.getSize(), "Size should be consistent during pops");
+        }
+    }
+
+    @Test
+    public void testMixedDataTypes() {
+        // If your stack supports Object types, test with different data types
+
+        stack.push(1);
+        stack.push(2);
+
+        assertEquals(Integer.valueOf(2), stack.pop());
+        assertEquals(Integer.valueOf(1), stack.pop());
+    }
 }

From edb8167374c7a1ec9078242495bb173d2a912750 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Fri, 25 Jul 2025 19:58:15 +0200
Subject: [PATCH 0914/1338] testing: improve test coverage `NodeStackTest`
 (#6432)

* testing: improve test coverage NodeStackTest

* style: fix style issues

* testing: fix type

* testing: fix import

* testing: fix import
---
 .../datastructures/stacks/NodeStackTest.java  | 181 +++++++++++++++++-
 1 file changed, 179 insertions(+), 2 deletions(-)

diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java
index 7ac0d8bc324b..8a89382211ba 100644
--- a/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/NodeStackTest.java
@@ -1,15 +1,26 @@
 package com.thealgorithms.datastructures.stacks;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
 class NodeStackTest {
 
+    private NodeStack<Integer> intStack;
+    private NodeStack<String> stringStack;
+
+    @BeforeEach
+    void setUp() {
+        intStack = new NodeStack<>();
+        stringStack = new NodeStack<>();
+    }
+
     @Test
+    @DisplayName("Test push operation")
     void testPush() {
         NodeStack<Integer> stack = new NodeStack<>();
         stack.push(10);
@@ -18,6 +29,7 @@ void testPush() {
     }
 
     @Test
+    @DisplayName("Test pop operation")
     void testPop() {
         NodeStack<String> stack = new NodeStack<>();
         stack.push("First");
@@ -27,12 +39,14 @@ void testPop() {
     }
 
     @Test
+    @DisplayName("Test pop on empty stack throws exception")
     void testPopOnEmptyStack() {
         NodeStack<Double> stack = new NodeStack<>();
         assertThrows(IllegalStateException.class, stack::pop, "Popping an empty stack should throw IllegalStateException.");
     }
 
     @Test
+    @DisplayName("Test peek operation")
     void testPeek() {
         NodeStack<Integer> stack = new NodeStack<>();
         stack.push(5);
@@ -43,22 +57,25 @@ void testPeek() {
     }
 
     @Test
+    @DisplayName("Test peek on empty stack throws exception")
     void testPeekOnEmptyStack() {
         NodeStack<String> stack = new NodeStack<>();
         assertThrows(IllegalStateException.class, stack::peek, "Peeking an empty stack should throw IllegalStateException.");
     }
 
     @Test
+    @DisplayName("Test isEmpty method")
     void testIsEmpty() {
         NodeStack<Character> stack = new NodeStack<>();
         assertTrue(stack.isEmpty(), "Newly initialized stack should be empty.");
         stack.push('A');
-        assertFalse(stack.isEmpty(), "Stack should not be empty after a push operation.");
+        org.junit.jupiter.api.Assertions.assertFalse(stack.isEmpty(), "Stack should not be empty after a push operation.");
         stack.pop();
         assertTrue(stack.isEmpty(), "Stack should be empty after popping the only element.");
     }
 
     @Test
+    @DisplayName("Test size method")
     void testSize() {
         NodeStack<Integer> stack = new NodeStack<>();
         assertEquals(0, stack.size(), "Size of empty stack should be 0.");
@@ -70,4 +87,164 @@ void testSize() {
         stack.pop();
         assertEquals(0, stack.size(), "Size should be 0 after popping all elements.");
     }
+
+    @Test
+    @DisplayName("Test push and pop with null values")
+    void testPushPopWithNull() {
+        stringStack.push(null);
+        stringStack.push("not null");
+        stringStack.push(null);
+
+        assertEquals(3, stringStack.size(), "Stack should contain 3 elements including nulls");
+        org.junit.jupiter.api.Assertions.assertNull(stringStack.pop(), "Should pop null value");
+        assertEquals("not null", stringStack.pop(), "Should pop 'not null' value");
+        org.junit.jupiter.api.Assertions.assertNull(stringStack.pop(), "Should pop null value");
+        assertTrue(stringStack.isEmpty(), "Stack should be empty after popping all elements");
+    }
+
+    @Test
+    @DisplayName("Test LIFO (Last In First Out) behavior")
+    void testLifoBehavior() {
+        int[] values = {1, 2, 3, 4, 5};
+
+        // Push values in order
+        for (int value : values) {
+            intStack.push(value);
+        }
+
+        // Pop values should be in reverse order
+        for (int i = values.length - 1; i >= 0; i--) {
+            assertEquals(values[i], intStack.pop(), "Elements should be popped in LIFO order");
+        }
+    }
+
+    @Test
+    @DisplayName("Test peek doesn't modify stack")
+    void testPeekDoesNotModifyStack() {
+        intStack.push(1);
+        intStack.push(2);
+        intStack.push(3);
+
+        int originalSize = intStack.size();
+        int peekedValue = intStack.peek();
+
+        assertEquals(3, peekedValue, "Peek should return top element");
+        assertEquals(originalSize, intStack.size(), "Peek should not change stack size");
+        assertEquals(3, intStack.peek(), "Multiple peeks should return same value");
+        org.junit.jupiter.api.Assertions.assertFalse(intStack.isEmpty(), "Peek should not make stack empty");
+    }
+
+    @Test
+    @DisplayName("Test mixed push and pop operations")
+    void testMixedOperations() {
+        // Test interleaved push/pop operations
+        intStack.push(1);
+        assertEquals(1, intStack.pop());
+        assertTrue(intStack.isEmpty());
+
+        intStack.push(2);
+        intStack.push(3);
+        assertEquals(3, intStack.pop());
+        intStack.push(4);
+        assertEquals(4, intStack.peek());
+        assertEquals(2, intStack.size());
+
+        assertEquals(4, intStack.pop());
+        assertEquals(2, intStack.pop());
+        assertTrue(intStack.isEmpty());
+    }
+
+    @Test
+    @DisplayName("Test stack with duplicate values")
+    void testStackWithDuplicates() {
+        intStack.push(1);
+        intStack.push(1);
+        intStack.push(1);
+
+        assertEquals(3, intStack.size(), "Stack should handle duplicate values");
+        assertEquals(1, intStack.peek(), "Peek should return duplicate value");
+
+        assertEquals(1, intStack.pop(), "Should pop first duplicate");
+        assertEquals(1, intStack.pop(), "Should pop second duplicate");
+        assertEquals(1, intStack.pop(), "Should pop third duplicate");
+        assertTrue(intStack.isEmpty(), "Stack should be empty after popping all duplicates");
+    }
+
+    @Test
+    @DisplayName("Test stack with different data types")
+    void testDifferentDataTypes() {
+        NodeStack<Character> charStack = new NodeStack<>();
+        NodeStack<Boolean> booleanStack = new NodeStack<>();
+
+        // Test with Character
+        charStack.push('A');
+        charStack.push('Z');
+        assertEquals('Z', charStack.peek(), "Should handle Character values");
+
+        // Test with Boolean
+        booleanStack.push(Boolean.TRUE);
+        booleanStack.push(Boolean.FALSE);
+        assertEquals(Boolean.FALSE, booleanStack.peek(), "Should handle Boolean values");
+    }
+
+    @Test
+    @DisplayName("Test stack state consistency after exceptions")
+    void testStateConsistencyAfterExceptions() {
+        // Stack should remain consistent after exception-throwing operations
+        intStack.push(1);
+        intStack.push(2);
+
+        // Try to peek and pop normally first
+        assertEquals(2, intStack.peek());
+        assertEquals(2, intStack.pop());
+        assertEquals(1, intStack.size());
+
+        // Pop remaining element
+        assertEquals(1, intStack.pop());
+        assertTrue(intStack.isEmpty());
+
+        // Now stack is empty, operations should throw exceptions
+        assertThrows(IllegalStateException.class, intStack::peek);
+        assertThrows(IllegalStateException.class, intStack::pop);
+
+        // Stack should still be in valid empty state
+        assertTrue(intStack.isEmpty());
+        assertEquals(0, intStack.size());
+
+        // Should be able to push after exceptions
+        intStack.push(3);
+        org.junit.jupiter.api.Assertions.assertFalse(intStack.isEmpty());
+        assertEquals(1, intStack.size());
+        assertEquals(3, intStack.peek());
+    }
+
+    @Test
+    @DisplayName("Test single element stack operations")
+    void testSingleElementStack() {
+        intStack.push(2);
+
+        org.junit.jupiter.api.Assertions.assertFalse(intStack.isEmpty(), "Stack with one element should not be empty");
+        assertEquals(1, intStack.size(), "Size should be 1");
+        assertEquals(2, intStack.peek(), "Peek should return the single element");
+        assertEquals(1, intStack.size(), "Peek should not change size");
+
+        assertEquals(2, intStack.pop(), "Pop should return the single element");
+        assertTrue(intStack.isEmpty(), "Stack should be empty after popping single element");
+        assertEquals(0, intStack.size(), "Size should be 0 after popping single element");
+    }
+
+    @Test
+    @DisplayName("Test toString method if implemented")
+    void testToString() {
+        // This test assumes NodeStack has a toString method
+        // If not implemented, this test can be removed or NodeStack can be enhanced
+        intStack.push(1);
+        intStack.push(2);
+        intStack.push(3);
+
+        String stackString = intStack.toString();
+        // Basic check that toString doesn't throw exception and returns something
+        assertTrue(stackString != null, "toString should not return null");
+        assertTrue(stackString.length() > 0, "toString should return non-empty string");
+    }
 }

From 040d3850ac943817c804dcd940b006ee2a657d66 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Fri, 25 Jul 2025 20:01:12 +0200
Subject: [PATCH 0915/1338] testing: improve `BagTest` (#6435)

* testing: improve BagTest

* style: fix checkstyle for BagTest

* testing: redundant test
---
 .../datastructures/bag/BagTest.java           | 115 ++++++++++++++++++
 1 file changed, 115 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java b/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
index b7e64851383c..8212793dfb79 100644
--- a/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
@@ -6,7 +6,10 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.datastructures.bags.Bag;
+import java.util.ArrayList;
 import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
 import org.junit.jupiter.api.Test;
 
 class BagTest {
@@ -156,4 +159,116 @@ void testIteratorWithDuplicates() {
         }
         assertEquals(3, count, "Iterator should traverse all 3 items including duplicates");
     }
+
+    @Test
+    void testCollectionElements() {
+        Bag<List<String>> bag = new Bag<>();
+        List<String> list1 = new ArrayList<>();
+        list1.add("a");
+        list1.add("b");
+
+        List<String> list2 = new ArrayList<>();
+        list2.add("c");
+
+        List<String> emptyList = new ArrayList<>();
+
+        bag.add(list1);
+        bag.add(list2);
+        bag.add(emptyList);
+        bag.add(list1); // Duplicate
+
+        assertEquals(4, bag.size(), "Bag should contain 4 list elements");
+        assertTrue(bag.contains(list1), "Bag should contain list1");
+        assertTrue(bag.contains(list2), "Bag should contain list2");
+        assertTrue(bag.contains(emptyList), "Bag should contain empty list");
+    }
+
+    @Test
+    void testIteratorConsistency() {
+        Bag<String> bag = new Bag<>();
+        bag.add("first");
+        bag.add("second");
+        bag.add("third");
+
+        // Multiple iterations should return same elements
+        List<String> firstIteration = new ArrayList<>();
+        for (String item : bag) {
+            firstIteration.add(item);
+        }
+
+        List<String> secondIteration = new ArrayList<>();
+        for (String item : bag) {
+            secondIteration.add(item);
+        }
+
+        assertEquals(firstIteration.size(), secondIteration.size(), "Both iterations should have same size");
+        assertEquals(3, firstIteration.size(), "First iteration should have 3 elements");
+        assertEquals(3, secondIteration.size(), "Second iteration should have 3 elements");
+    }
+
+    @Test
+    void testMultipleIterators() {
+        Bag<String> bag = new Bag<>();
+        bag.add("item1");
+        bag.add("item2");
+
+        Iterator<String> iter1 = bag.iterator();
+        Iterator<String> iter2 = bag.iterator();
+
+        assertTrue(iter1.hasNext(), "First iterator should have next element");
+        assertTrue(iter2.hasNext(), "Second iterator should have next element");
+
+        String first1 = iter1.next();
+        String first2 = iter2.next();
+
+        org.junit.jupiter.api.Assertions.assertNotNull(first1, "First iterator should return non-null element");
+        org.junit.jupiter.api.Assertions.assertNotNull(first2, "Second iterator should return non-null element");
+    }
+
+    @Test
+    void testIteratorHasNextConsistency() {
+        Bag<String> bag = new Bag<>();
+        bag.add("single");
+
+        Iterator<String> iter = bag.iterator();
+        assertTrue(iter.hasNext(), "hasNext should return true");
+        assertTrue(iter.hasNext(), "hasNext should still return true after multiple calls");
+
+        String item = iter.next();
+        assertEquals("single", item, "Next should return the single item");
+
+        assertFalse(iter.hasNext(), "hasNext should return false after consuming element");
+        assertFalse(iter.hasNext(), "hasNext should still return false");
+    }
+
+    @Test
+    void testIteratorNextOnEmptyBag() {
+        Bag<String> bag = new Bag<>();
+        Iterator<String> iter = bag.iterator();
+
+        assertFalse(iter.hasNext(), "hasNext should return false for empty bag");
+        assertThrows(NoSuchElementException.class, iter::next, "next() should throw NoSuchElementException on empty bag");
+    }
+
+    @Test
+    void testBagOrderIndependence() {
+        Bag<String> bag1 = new Bag<>();
+        Bag<String> bag2 = new Bag<>();
+
+        // Add same elements in different order
+        bag1.add("first");
+        bag1.add("second");
+        bag1.add("third");
+
+        bag2.add("third");
+        bag2.add("first");
+        bag2.add("second");
+
+        assertEquals(bag1.size(), bag2.size(), "Bags should have same size");
+
+        // Both bags should contain all elements
+        assertTrue(bag1.contains("first") && bag2.contains("first"));
+        assertTrue(bag1.contains("second") && bag2.contains("second"));
+        assertTrue(bag1.contains("third") && bag2.contains("third"));
+    }
 }

From 032f75c0f47e1ba21f9c6d1867d63400fb6ec7fb Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Fri, 25 Jul 2025 20:04:52 +0200
Subject: [PATCH 0916/1338] testing: improve `DisjointSetUnionTest` (#6440)

* testing: improve DisjointSetUnionTest

* testing: redundant variable for DisjointSetUnionTest
---
 .../DisjointSetUnionTest.java                 | 105 ++++++++++++++++++
 1 file changed, 105 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java b/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java
index 14dceb53c40d..581bac6151dd 100644
--- a/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java
@@ -122,4 +122,109 @@ public void testPathCompression() {
         assertEquals(root, node1);
         assertEquals(node1, node3.parent);
     }
+
+    @Test
+    public void testUnionByRankSmallerToLarger() {
+        DisjointSetUnion<Integer> dsu = new DisjointSetUnion<>();
+        Node<Integer> node1 = dsu.makeSet(1);
+        Node<Integer> node2 = dsu.makeSet(2);
+        Node<Integer> node3 = dsu.makeSet(3);
+
+        // Create tree with node1 as root and rank 1
+        dsu.unionSets(node1, node2);
+        assertEquals(1, node1.rank);
+        assertEquals(0, node2.rank);
+
+        // Union single node (rank 0) with tree (rank 1)
+        // Smaller rank tree should attach to larger rank tree
+        dsu.unionSets(node3, node1);
+        assertEquals(node1, dsu.findSet(node3));
+        assertEquals(1, node1.rank); // Rank should not increase
+    }
+
+    @Test
+    public void testUnionByRankEqualRanks() {
+        DisjointSetUnion<Integer> dsu = new DisjointSetUnion<>();
+        Node<Integer> node1 = dsu.makeSet(1);
+        Node<Integer> node2 = dsu.makeSet(2);
+        Node<Integer> node3 = dsu.makeSet(3);
+        Node<Integer> node4 = dsu.makeSet(4);
+
+        // Create two trees of equal rank (1)
+        dsu.unionSets(node1, node2);
+        dsu.unionSets(node3, node4);
+        assertEquals(1, node1.rank);
+        assertEquals(1, node3.rank);
+
+        // Union two trees of equal rank
+        dsu.unionSets(node1, node3);
+        Node<Integer> root = dsu.findSet(node1);
+        assertEquals(2, root.rank); // Rank should increase by 1
+    }
+
+    @Test
+    public void testLargeChainPathCompression() {
+        DisjointSetUnion<Integer> dsu = new DisjointSetUnion<>();
+        Node<Integer> node1 = dsu.makeSet(1);
+        Node<Integer> node2 = dsu.makeSet(2);
+        Node<Integer> node3 = dsu.makeSet(3);
+        Node<Integer> node4 = dsu.makeSet(4);
+        Node<Integer> node5 = dsu.makeSet(5);
+
+        // Create a long chain: 1 -> 2 -> 3 -> 4 -> 5
+        dsu.unionSets(node1, node2);
+        dsu.unionSets(node2, node3);
+        dsu.unionSets(node3, node4);
+        dsu.unionSets(node4, node5);
+
+        // Find from the deepest node
+        Node<Integer> root = dsu.findSet(node5);
+
+        // Path compression should make all nodes point directly to root
+        assertEquals(root, node5.parent);
+        assertEquals(root, node4.parent);
+        assertEquals(root, node3.parent);
+        assertEquals(root, node2.parent);
+        assertEquals(root, node1.parent);
+    }
+
+    @Test
+    public void testMultipleDisjointSets() {
+        DisjointSetUnion<Integer> dsu = new DisjointSetUnion<>();
+        Node<Integer> node1 = dsu.makeSet(1);
+        Node<Integer> node2 = dsu.makeSet(2);
+        Node<Integer> node3 = dsu.makeSet(3);
+        Node<Integer> node4 = dsu.makeSet(4);
+        Node<Integer> node5 = dsu.makeSet(5);
+        Node<Integer> node6 = dsu.makeSet(6);
+
+        // Create two separate components
+        dsu.unionSets(node1, node2);
+        dsu.unionSets(node2, node3);
+
+        dsu.unionSets(node4, node5);
+        dsu.unionSets(node5, node6);
+
+        // Verify they are separate
+        assertEquals(dsu.findSet(node1), dsu.findSet(node2));
+        assertEquals(dsu.findSet(node2), dsu.findSet(node3));
+        assertEquals(dsu.findSet(node4), dsu.findSet(node5));
+        assertEquals(dsu.findSet(node5), dsu.findSet(node6));
+
+        assertNotEquals(dsu.findSet(node1), dsu.findSet(node4));
+        assertNotEquals(dsu.findSet(node3), dsu.findSet(node6));
+    }
+
+    @Test
+    public void testEmptyValues() {
+        DisjointSetUnion<String> dsu = new DisjointSetUnion<>();
+        Node<String> emptyNode = dsu.makeSet("");
+        Node<String> nullNode = dsu.makeSet(null);
+
+        assertEquals(emptyNode, dsu.findSet(emptyNode));
+        assertEquals(nullNode, dsu.findSet(nullNode));
+
+        dsu.unionSets(emptyNode, nullNode);
+        assertEquals(dsu.findSet(emptyNode), dsu.findSet(nullNode));
+    }
 }

From 2eb80fb84354a1d35e8360dce77d7a3d8079a950 Mon Sep 17 00:00:00 2001
From: Lucas Gomes <luquitagm1818@gmail.com>
Date: Sat, 26 Jul 2025 05:34:00 -0300
Subject: [PATCH 0917/1338] Remove duplicate SimpleSort (same logic as
 ExchangeSort) (#6441)

* Remove duplicate SimpleSort (same logic as ExchangeSort)

* Removed test class for SimpleSort as it was also duplicate

---------

Co-authored-by: Lucas G <lucasgomesm1808@gmail.com>
---
 .../java/com/thealgorithms/sorts/SimpleSort.java  | 15 ---------------
 .../com/thealgorithms/sorts/SimpleSortTest.java   |  8 --------
 2 files changed, 23 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/sorts/SimpleSort.java
 delete mode 100644 src/test/java/com/thealgorithms/sorts/SimpleSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/SimpleSort.java b/src/main/java/com/thealgorithms/sorts/SimpleSort.java
deleted file mode 100644
index a03223cb01a1..000000000000
--- a/src/main/java/com/thealgorithms/sorts/SimpleSort.java
+++ /dev/null
@@ -1,15 +0,0 @@
-package com.thealgorithms.sorts;
-
-public class SimpleSort implements SortAlgorithm {
-    @Override
-    public <T extends Comparable<T>> T[] sort(T[] array) {
-        for (int i = 0; i < array.length; i++) {
-            for (int j = i + 1; j < array.length; j++) {
-                if (SortUtils.less(array[j], array[i])) {
-                    SortUtils.swap(array, i, j);
-                }
-            }
-        }
-        return array;
-    }
-}
diff --git a/src/test/java/com/thealgorithms/sorts/SimpleSortTest.java b/src/test/java/com/thealgorithms/sorts/SimpleSortTest.java
deleted file mode 100644
index 887b314e46ff..000000000000
--- a/src/test/java/com/thealgorithms/sorts/SimpleSortTest.java
+++ /dev/null
@@ -1,8 +0,0 @@
-package com.thealgorithms.sorts;
-
-public class SimpleSortTest extends SortingAlgorithmTest {
-    @Override
-    SortAlgorithm getSortAlgorithm() {
-        return new SimpleSort();
-    }
-}

From a8b579e293d577d3f320b3b212da41fc8023aa0d Mon Sep 17 00:00:00 2001
From: dinishajais <113303387+dinishajais@users.noreply.github.com>
Date: Sat, 26 Jul 2025 14:07:54 +0530
Subject: [PATCH 0918/1338] #6336/enhancement/Refactor: Standardize comparison
 logic using SortUtils (#6442)

* Refactoring compareTo() to SortUtils methods

* Adding formatting

* Removed excess parenthesis

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../java/com/thealgorithms/sorts/AdaptiveMergeSort.java   | 2 +-
 .../java/com/thealgorithms/sorts/BinaryInsertionSort.java | 2 +-
 src/main/java/com/thealgorithms/sorts/BitonicSort.java    | 2 +-
 src/main/java/com/thealgorithms/sorts/BucketSort.java     | 4 ++--
 src/main/java/com/thealgorithms/sorts/CircleSort.java     | 4 ++--
 .../com/thealgorithms/sorts/DutchNationalFlagSort.java    | 4 ++--
 src/main/java/com/thealgorithms/sorts/ExchangeSort.java   | 2 +-
 .../java/com/thealgorithms/sorts/IntrospectiveSort.java   | 8 ++++----
 src/main/java/com/thealgorithms/sorts/OddEvenSort.java    | 4 ++--
 src/main/java/com/thealgorithms/sorts/SelectionSort.java  | 2 +-
 .../com/thealgorithms/sorts/SelectionSortRecursive.java   | 2 +-
 src/main/java/com/thealgorithms/sorts/StalinSort.java     | 2 +-
 12 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java b/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java
index 2c71bae8b557..09ea349875ac 100644
--- a/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java
@@ -30,7 +30,7 @@ private <T extends Comparable<T>> void merge(T[] array, T[] aux, int low, int mi
                 array[k] = aux[j++];
             } else if (j > high) {
                 array[k] = aux[i++];
-            } else if (aux[j].compareTo(aux[i]) < 0) {
+            } else if (SortUtils.less(aux[j], aux[i])) {
                 array[k] = aux[j++];
             } else {
                 array[k] = aux[i++];
diff --git a/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java b/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java
index b6f5d92e7928..b8086bd0ebca 100644
--- a/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BinaryInsertionSort.java
@@ -22,7 +22,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
 
             while (low <= high) {
                 final int mid = (low + high) >>> 1;
-                if (temp.compareTo(array[mid]) < 0) {
+                if (SortUtils.less(temp, array[mid])) {
                     high = mid - 1;
                 } else {
                     low = mid + 1;
diff --git a/src/main/java/com/thealgorithms/sorts/BitonicSort.java b/src/main/java/com/thealgorithms/sorts/BitonicSort.java
index 90d204818729..1c1a3ac45540 100644
--- a/src/main/java/com/thealgorithms/sorts/BitonicSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BitonicSort.java
@@ -64,7 +64,7 @@ private <T extends Comparable<T>> void bitonicMerge(T[] array, int low, int cnt,
         if (cnt > 1) {
             final int k = cnt / 2;
 
-            final BiPredicate<T, T> areSorted = (direction == Direction.ASCENDING) ? (a, b) -> a.compareTo(b) < 0 : (a, b) -> a.compareTo(b) > 0;
+            final BiPredicate<T, T> areSorted = (direction == Direction.ASCENDING) ? (a, b) -> SortUtils.less(a, b) : (a, b) -> SortUtils.greater(a, b);
             for (int i = low; i < low + k; i++) {
                 if (!areSorted.test(array[i], array[i + k])) {
                     SortUtils.swap(array, i, i + k);
diff --git a/src/main/java/com/thealgorithms/sorts/BucketSort.java b/src/main/java/com/thealgorithms/sorts/BucketSort.java
index 62c5e929593b..8882a1cb4bbd 100644
--- a/src/main/java/com/thealgorithms/sorts/BucketSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BucketSort.java
@@ -111,7 +111,7 @@ private <T extends Comparable<T>> int hash(final T element, final T min, final T
     private <T extends Comparable<T>> T findMin(T[] array) {
         T min = array[0];
         for (T element : array) {
-            if (element.compareTo(min) < 0) {
+            if (SortUtils.less(element, min)) {
                 min = element;
             }
         }
@@ -121,7 +121,7 @@ private <T extends Comparable<T>> T findMin(T[] array) {
     private <T extends Comparable<T>> T findMax(T[] array) {
         T max = array[0];
         for (T element : array) {
-            if (element.compareTo(max) > 0) {
+            if (SortUtils.greater(element, max)) {
                 max = element;
             }
         }
diff --git a/src/main/java/com/thealgorithms/sorts/CircleSort.java b/src/main/java/com/thealgorithms/sorts/CircleSort.java
index b9b41be16701..2863a40a2075 100644
--- a/src/main/java/com/thealgorithms/sorts/CircleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/CircleSort.java
@@ -36,7 +36,7 @@ private <T extends Comparable<T>> boolean doSort(final T[] array, final int left
         int high = right;
 
         while (low < high) {
-            if (array[low].compareTo(array[high]) > 0) {
+            if (SortUtils.greater(array[low], array[high])) {
                 SortUtils.swap(array, low, high);
                 swapped = true;
             }
@@ -44,7 +44,7 @@ private <T extends Comparable<T>> boolean doSort(final T[] array, final int left
             high--;
         }
 
-        if (low == high && array[low].compareTo(array[high + 1]) > 0) {
+        if (low == high && SortUtils.greater(array[low], array[high + 1])) {
             SortUtils.swap(array, low, high + 1);
             swapped = true;
         }
diff --git a/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java b/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java
index abfcb452b29a..f7e12da06568 100644
--- a/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DutchNationalFlagSort.java
@@ -26,11 +26,11 @@ private <T extends Comparable<T>> T[] dutchNationalFlagSort(final T[] array, fin
         int k = array.length - 1;
 
         while (j <= k) {
-            if (0 > array[j].compareTo(intendedMiddle)) {
+            if (SortUtils.less(array[j], intendedMiddle)) {
                 SortUtils.swap(array, i, j);
                 j++;
                 i++;
-            } else if (0 < array[j].compareTo(intendedMiddle)) {
+            } else if (SortUtils.greater(array[j], intendedMiddle)) {
                 SortUtils.swap(array, j, k);
                 k--;
             } else {
diff --git a/src/main/java/com/thealgorithms/sorts/ExchangeSort.java b/src/main/java/com/thealgorithms/sorts/ExchangeSort.java
index 67e94b889671..a58caaf1031a 100644
--- a/src/main/java/com/thealgorithms/sorts/ExchangeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/ExchangeSort.java
@@ -31,7 +31,7 @@ class ExchangeSort implements SortAlgorithm {
     public <T extends Comparable<T>> T[] sort(T[] array) {
         for (int i = 0; i < array.length - 1; i++) {
             for (int j = i + 1; j < array.length; j++) {
-                if (array[i].compareTo(array[j]) > 0) {
+                if (SortUtils.greater(array[i], array[j])) {
                     SortUtils.swap(array, i, j);
                 }
             }
diff --git a/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java b/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java
index 12ef197b931b..6f846c7b9a8f 100644
--- a/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java
+++ b/src/main/java/com/thealgorithms/sorts/IntrospectiveSort.java
@@ -63,7 +63,7 @@ private static <T extends Comparable<T>> int partition(T[] array, final int low,
         final T pivot = array[high];
         int i = low - 1;
         for (int j = low; j < high; j++) {
-            if (array[j].compareTo(pivot) <= 0) {
+            if (SortUtils.greaterOrEqual(pivot, array[j])) {
                 i++;
                 SortUtils.swap(array, i, j);
             }
@@ -84,7 +84,7 @@ private static <T extends Comparable<T>> void insertionSort(T[] array, final int
         for (int i = low + 1; i <= high; i++) {
             final T key = array[i];
             int j = i - 1;
-            while (j >= low && array[j].compareTo(key) > 0) {
+            while (j >= low && SortUtils.greater(array[j], key)) {
                 array[j + 1] = array[j];
                 j--;
             }
@@ -125,10 +125,10 @@ private static <T extends Comparable<T>> void heapify(T[] array, final int i, fi
         final int right = 2 * i + 2;
         int largest = i;
 
-        if (left < n && array[low + left].compareTo(array[low + largest]) > 0) {
+        if (left < n && SortUtils.greater(array[low + left], array[low + largest])) {
             largest = left;
         }
-        if (right < n && array[low + right].compareTo(array[low + largest]) > 0) {
+        if (right < n && SortUtils.greater(array[low + right], array[low + largest])) {
             largest = right;
         }
         if (largest != i) {
diff --git a/src/main/java/com/thealgorithms/sorts/OddEvenSort.java b/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
index ac94982c1474..b854842e9645 100644
--- a/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
+++ b/src/main/java/com/thealgorithms/sorts/OddEvenSort.java
@@ -30,7 +30,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
     private <T extends Comparable<T>> boolean performOddSort(T[] array) {
         boolean sorted = true;
         for (int i = 1; i < array.length - 1; i += 2) {
-            if (array[i].compareTo(array[i + 1]) > 0) {
+            if (SortUtils.greater(array[i], array[i + 1])) {
                 SortUtils.swap(array, i, i + 1);
                 sorted = false;
             }
@@ -41,7 +41,7 @@ private <T extends Comparable<T>> boolean performOddSort(T[] array) {
     private <T extends Comparable<T>> boolean performEvenSort(T[] array) {
         boolean sorted = true;
         for (int i = 0; i < array.length - 1; i += 2) {
-            if (array[i].compareTo(array[i + 1]) > 0) {
+            if (SortUtils.greater(array[i], array[i + 1])) {
                 SortUtils.swap(array, i, i + 1);
                 sorted = false;
             }
diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSort.java b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
index dbb2b88ffcef..db7732d7e218 100644
--- a/src/main/java/com/thealgorithms/sorts/SelectionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
@@ -21,7 +21,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
     private static <T extends Comparable<T>> int findIndexOfMin(T[] array, final int startIndex) {
         int minIndex = startIndex;
         for (int i = startIndex + 1; i < array.length; i++) {
-            if (array[i].compareTo(array[minIndex]) < 0) {
+            if (SortUtils.less(array[i], array[minIndex])) {
                 minIndex = i;
             }
         }
diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java b/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
index 9d24542de592..f220c2d8f994 100644
--- a/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java
@@ -56,6 +56,6 @@ private static <T extends Comparable<T>> int findMinIndex(T[] array, final int s
         final int minIndexInRest = findMinIndex(array, start + 1);
 
         // Return the index of the smaller element between array[start] and the minimum element in the rest of the array
-        return array[start].compareTo(array[minIndexInRest]) < 0 ? start : minIndexInRest;
+        return SortUtils.less(array[start], array[minIndexInRest]) ? start : minIndexInRest;
     }
 }
diff --git a/src/main/java/com/thealgorithms/sorts/StalinSort.java b/src/main/java/com/thealgorithms/sorts/StalinSort.java
index 5aaf530fd94c..fe07a6f6d986 100644
--- a/src/main/java/com/thealgorithms/sorts/StalinSort.java
+++ b/src/main/java/com/thealgorithms/sorts/StalinSort.java
@@ -8,7 +8,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         }
         int currentIndex = 0;
         for (int i = 1; i < array.length; i++) {
-            if (array[i].compareTo(array[currentIndex]) >= 0) {
+            if (SortUtils.greaterOrEqual(array[i], array[currentIndex])) {
                 currentIndex++;
                 array[currentIndex] = array[i];
             }

From 2b18008811d9ffc200b8cf91c61b24d2109584a7 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Sat, 26 Jul 2025 10:45:38 +0200
Subject: [PATCH 0919/1338] Update DIRECTORY.md (#6446)

Co-authored-by: DenizAltunkapan <DenizAltunkapan@users.noreply.github.com>
---
 DIRECTORY.md | 2 --
 1 file changed, 2 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 9067f17ebc2d..71d4b7d013cb 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -676,7 +676,6 @@
           - 📄 [SelectionSort](src/main/java/com/thealgorithms/sorts/SelectionSort.java)
           - 📄 [SelectionSortRecursive](src/main/java/com/thealgorithms/sorts/SelectionSortRecursive.java)
           - 📄 [ShellSort](src/main/java/com/thealgorithms/sorts/ShellSort.java)
-          - 📄 [SimpleSort](src/main/java/com/thealgorithms/sorts/SimpleSort.java)
           - 📄 [SlowSort](src/main/java/com/thealgorithms/sorts/SlowSort.java)
           - 📄 [SortAlgorithm](src/main/java/com/thealgorithms/sorts/SortAlgorithm.java)
           - 📄 [SortUtils](src/main/java/com/thealgorithms/sorts/SortUtils.java)
@@ -1348,7 +1347,6 @@
           - 📄 [SelectionSortRecursiveTest](src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java)
           - 📄 [SelectionSortTest](src/test/java/com/thealgorithms/sorts/SelectionSortTest.java)
           - 📄 [ShellSortTest](src/test/java/com/thealgorithms/sorts/ShellSortTest.java)
-          - 📄 [SimpleSortTest](src/test/java/com/thealgorithms/sorts/SimpleSortTest.java)
           - 📄 [SlowSortTest](src/test/java/com/thealgorithms/sorts/SlowSortTest.java)
           - 📄 [SortUtilsRandomGeneratorTest](src/test/java/com/thealgorithms/sorts/SortUtilsRandomGeneratorTest.java)
           - 📄 [SortUtilsTest](src/test/java/com/thealgorithms/sorts/SortUtilsTest.java)

From 066a10979b339828d0c93d736e83ff0e35d0e4b7 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sat, 26 Jul 2025 19:38:25 +0200
Subject: [PATCH 0920/1338] testing: improve `BloomFilterTest` (#6443)

* testing: improve BloomFilterTest

* style: fix formatting
---
 .../bloomfilter/BloomFilterTest.java          | 143 ++++++++++++++++++
 1 file changed, 143 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java b/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java
index 048eb7e481a7..9e1ba88adaee 100644
--- a/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/bloomfilter/BloomFilterTest.java
@@ -1,5 +1,12 @@
 package com.thealgorithms.datastructures.bloomfilter;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -113,4 +120,140 @@ void testBoundaryConditions() {
         Assertions.assertTrue(filter.contains("d"), "Filter should contain 'd'");
         Assertions.assertFalse(filter.contains("e"), "Filter should not contain 'e' which was not inserted");
     }
+
+    @Test
+    void testLongDataType() {
+        BloomFilter<Long> filter = new BloomFilter<>(5, 1000);
+        Long[] values = {Long.MIN_VALUE, Long.MAX_VALUE};
+
+        for (Long value : values) {
+            filter.insert(value);
+        }
+
+        for (Long value : values) {
+            Assertions.assertTrue(filter.contains(value), "Filter should contain " + value);
+        }
+    }
+
+    @Test
+    void testFloatDataType() {
+        BloomFilter<Float> filter = new BloomFilter<>(3, 200);
+        Float[] values = {1.5f, -3.7f, 0.0f, Float.MAX_VALUE, Float.MIN_VALUE};
+
+        for (Float value : values) {
+            filter.insert(value);
+        }
+
+        for (Float value : values) {
+            Assertions.assertTrue(filter.contains(value), "Filter should contain " + value);
+        }
+
+        Assertions.assertFalse(filter.contains(88.88f), "Filter should not contain uninserted value");
+    }
+
+    @Test
+    void testBooleanDataType() {
+        BloomFilter<Boolean> filter = new BloomFilter<>(2, 50);
+        filter.insert(Boolean.TRUE);
+        filter.insert(Boolean.FALSE);
+
+        Assertions.assertTrue(filter.contains(Boolean.TRUE), "Filter should contain true");
+        Assertions.assertTrue(filter.contains(Boolean.FALSE), "Filter should contain false");
+    }
+
+    @Test
+    void testListDataType() {
+        BloomFilter<List<String>> filter = new BloomFilter<>(4, 200);
+        List<String> list1 = Arrays.asList("apple", "banana");
+        List<String> list2 = Arrays.asList("cat", "dog");
+        List<String> emptyList = new ArrayList<>();
+
+        filter.insert(list1);
+        filter.insert(list2);
+        filter.insert(emptyList);
+
+        Assertions.assertTrue(filter.contains(list1), "Filter should contain list1");
+        Assertions.assertTrue(filter.contains(list2), "Filter should contain list2");
+        Assertions.assertTrue(filter.contains(emptyList), "Filter should contain empty list");
+        Assertions.assertFalse(filter.contains(Arrays.asList("elephant", "tiger")), "Filter should not contain uninserted list");
+    }
+
+    @Test
+    void testMapDataType() {
+        BloomFilter<Map<String, Integer>> filter = new BloomFilter<>(3, 150);
+        Map<String, Integer> map1 = new HashMap<>();
+        map1.put("key1", 1);
+        map1.put("key2", 2);
+
+        Map<String, Integer> map2 = new HashMap<>();
+        map2.put("key3", 3);
+
+        Map<String, Integer> emptyMap = new HashMap<>();
+
+        filter.insert(map1);
+        filter.insert(map2);
+        filter.insert(emptyMap);
+
+        Assertions.assertTrue(filter.contains(map1), "Filter should contain map1");
+        Assertions.assertTrue(filter.contains(map2), "Filter should contain map2");
+        Assertions.assertTrue(filter.contains(emptyMap), "Filter should contain empty map");
+    }
+
+    @Test
+    void testSetDataType() {
+        BloomFilter<Set<Integer>> filter = new BloomFilter<>(3, 100);
+        Set<Integer> set1 = new HashSet<>(Arrays.asList(1, 2, 3));
+        Set<Integer> set2 = new HashSet<>(Arrays.asList(4, 5));
+        Set<Integer> emptySet = new HashSet<>();
+
+        filter.insert(set1);
+        filter.insert(set2);
+        filter.insert(emptySet);
+
+        Assertions.assertTrue(filter.contains(set1), "Filter should contain set1");
+        Assertions.assertTrue(filter.contains(set2), "Filter should contain set2");
+        Assertions.assertTrue(filter.contains(emptySet), "Filter should contain empty set");
+        Assertions.assertFalse(filter.contains(new HashSet<>(Arrays.asList(6, 7, 8))), "Filter should not contain uninserted set");
+    }
+
+    @Test
+    void testArrayDataType() {
+        BloomFilter<int[]> filter = new BloomFilter<>(3, 100);
+        int[] array1 = {1, 2, 3};
+        int[] array2 = {4, 5};
+        int[] emptyArray = {};
+
+        filter.insert(array1);
+        filter.insert(array2);
+        filter.insert(emptyArray);
+
+        Assertions.assertTrue(filter.contains(array1), "Filter should contain array1");
+        Assertions.assertTrue(filter.contains(array2), "Filter should contain array2");
+        Assertions.assertTrue(filter.contains(emptyArray), "Filter should contain empty array");
+        Assertions.assertFalse(filter.contains(new int[] {6, 7, 8}), "Filter should not contain different array");
+    }
+
+    @Test
+    void testSpecialFloatingPointValues() {
+        BloomFilter<Double> filter = new BloomFilter<>(3, 100);
+        Double[] specialValues = {Double.NaN, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY, -0.0, 0.0};
+
+        for (Double value : specialValues) {
+            filter.insert(value);
+        }
+
+        for (Double value : specialValues) {
+            Assertions.assertTrue(filter.contains(value), "Filter should contain " + value);
+        }
+    }
+
+    @Test
+    void testVerySmallBloomFilter() {
+        BloomFilter<String> smallFilter = new BloomFilter<>(1, 5);
+        smallFilter.insert("test1");
+        smallFilter.insert("test2");
+
+        Assertions.assertTrue(smallFilter.contains("test1"));
+        Assertions.assertTrue(smallFilter.contains("test2"));
+    }
 }

From 0081d5c73a7f86a2be8bd9a279727c5878a1762f Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sun, 27 Jul 2025 10:46:42 +0200
Subject: [PATCH 0921/1338] testing: improve testing `CRCAlgorithmTest` (#6444)

* testing: improve testing CRCAlgorithmTest

* style: formatting fix
---
 .../others/CRCAlgorithmTest.java              | 81 +++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java b/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java
index 542c256a3e88..3dc61f2c6569 100644
--- a/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java
@@ -79,4 +79,85 @@ void testLargeMessageSize() {
         assertTrue(c.getWrongMess() >= 0);
         assertTrue(c.getCorrectMess() >= 0);
     }
+
+    @Test
+    void testSingleBitMessage() {
+        CRCAlgorithm c = new CRCAlgorithm("11", 1, 0.0);
+        c.generateRandomMess();
+        c.divideMessageWithP(false);
+        c.changeMess();
+        c.divideMessageWithP(true);
+
+        assertTrue(c.getCorrectMess() >= 0, "Single bit message should be handled");
+    }
+
+    @Test
+    void testPolynomialLongerThanMessage() {
+        CRCAlgorithm c = new CRCAlgorithm("11010101", 3, 0.0);
+        c.generateRandomMess();
+        c.divideMessageWithP(false);
+        c.changeMess();
+        c.divideMessageWithP(true);
+
+        // Should not crash, counters should be valid
+        assertTrue(c.getCorrectMess() + c.getWrongMess() >= 0);
+    }
+
+    @Test
+    void testPolynomialWithOnlyOnes() {
+        CRCAlgorithm c = new CRCAlgorithm("1111", 5, 0.1);
+        c.generateRandomMess();
+        c.divideMessageWithP(false);
+        c.changeMess();
+        c.divideMessageWithP(true);
+
+        assertTrue(c.getCorrectMess() + c.getWrongMess() >= 0);
+    }
+
+    @Test
+    void testMultipleRefactorCalls() {
+        CRCAlgorithm c = new CRCAlgorithm("1101", 5, 0.2);
+
+        for (int i = 0; i < 5; i++) {
+            c.refactor();
+            c.generateRandomMess();
+            c.divideMessageWithP(false);
+            c.changeMess();
+            c.divideMessageWithP(true);
+        }
+
+        // Counters should accumulate across multiple runs
+        assertTrue(c.getCorrectMess() + c.getWrongMess() > 0);
+    }
+
+    @Test
+    void testCounterConsistency() {
+        CRCAlgorithm c = new CRCAlgorithm("1101", 10, 0.3);
+
+        for (int i = 0; i < 100; i++) {
+            c.refactor();
+            c.generateRandomMess();
+            c.divideMessageWithP(false);
+            c.changeMess();
+            c.divideMessageWithP(true);
+        }
+
+        // Total messages processed should equal correct + wrong
+        int totalProcessed = c.getCorrectMess() + c.getWrongMess();
+        assertEquals(100, totalProcessed, "Total processed messages should equal iterations");
+
+        // Wrong messages should equal caught + not caught
+        assertEquals(c.getWrongMess(), c.getWrongMessCaught() + c.getWrongMessNotCaught(), "Wrong messages should equal sum of caught and not caught");
+    }
+
+    @Test
+    void testGetterMethodsInitialState() {
+        CRCAlgorithm c = new CRCAlgorithm("1101", 10, 0.1);
+
+        // Check initial state
+        assertEquals(0, c.getCorrectMess(), "Initial correct messages should be 0");
+        assertEquals(0, c.getWrongMess(), "Initial wrong messages should be 0");
+        assertEquals(0, c.getWrongMessCaught(), "Initial caught wrong messages should be 0");
+        assertEquals(0, c.getWrongMessNotCaught(), "Initial not caught wrong messages should be 0");
+    }
 }

From 24f4090210fb68b287df9c4ba37b804c6135ef04 Mon Sep 17 00:00:00 2001
From: Oleksandr Klymenko <alexanderklmn@gmail.com>
Date: Sun, 27 Jul 2025 10:50:41 +0200
Subject: [PATCH 0922/1338] testing: improve `MergeKSortedLinkedListTes`
 (#6445)

testing: improve MergeKSortedLinkedListTest

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../lists/MergeKSortedLinkedListTest.java     | 84 +++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java
index 99a890112d31..8d3150d18ed0 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java
@@ -90,4 +90,88 @@ private int[] getListValues(Node head) {
         }
         return Arrays.copyOf(values, i); // return only filled part
     }
+
+    @Test
+    void testMergeWithNullListsInArray() {
+        Node list1 = new Node(1, new Node(3));
+        Node list2 = null;
+        Node list3 = new Node(2, new Node(4));
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 2, 3, 4};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Should handle null lists mixed with valid lists");
+    }
+
+    @Test
+    void testMergeWithDuplicateValues() {
+        Node list1 = new Node(1, new Node(1, new Node(3)));
+        Node list2 = new Node(1, new Node(2, new Node(3)));
+        Node list3 = new Node(3, new Node(3));
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 1, 1, 2, 3, 3, 3, 3};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Should handle duplicate values correctly");
+    }
+
+    @Test
+    void testMergeWithZeroLength() {
+        Node[] lists = {};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, 0);
+
+        assertNull(mergedHead, "Should return null for zero-length array");
+    }
+
+    @Test
+    void testMergeWithNegativeNumbers() {
+        Node list1 = new Node(-5, new Node(-1, new Node(3)));
+        Node list2 = new Node(-3, new Node(0, new Node(2)));
+        Node[] lists = {list1, list2};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {-5, -3, -1, 0, 2, 3};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Should handle negative numbers correctly");
+    }
+
+    @Test
+    void testMergeIdenticalLists() {
+        Node list1 = new Node(1, new Node(2, new Node(3)));
+        Node list2 = new Node(1, new Node(2, new Node(3)));
+        Node list3 = new Node(1, new Node(2, new Node(3)));
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 1, 1, 2, 2, 2, 3, 3, 3};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Should merge identical lists correctly");
+    }
+
+    @Test
+    void testMergeAlreadySortedSequence() {
+        Node list1 = new Node(1, new Node(2));
+        Node list2 = new Node(3, new Node(4));
+        Node list3 = new Node(5, new Node(6));
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 2, 3, 4, 5, 6};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Should handle already sorted sequence");
+    }
 }

From e09c98578fff95c1524a5b6f11ae1fb7571a485f Mon Sep 17 00:00:00 2001
From: Navaneedan S <navaneedannaveen07@gmail.com>
Date: Sat, 2 Aug 2025 00:46:10 +0530
Subject: [PATCH 0923/1338] Add ReverseStringUsingStack (#6452)

* Refactored ReverseStringUsingStack
* Add ReverseStringUsingStack
* Refactored ReverseStringUsingStack
* Closes #6451
---
 .../thealgorithms/strings/ReverseString.java  | 29 +++++++++++++++++++
 .../strings/ReverseStringTest.java            | 13 +++++++++
 2 files changed, 42 insertions(+)

diff --git a/src/main/java/com/thealgorithms/strings/ReverseString.java b/src/main/java/com/thealgorithms/strings/ReverseString.java
index 54a9b779e828..996aa68bb307 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseString.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseString.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.strings;
 
+import java.util.Stack;
+
 /**
  * Reverse String using different version
  */
@@ -57,4 +59,31 @@ public static String reverse3(String string) {
         }
         return sb.toString();
     }
+    /**
+     * Reverses the given string using a stack.
+     * This method uses a stack to reverse the characters of the string.
+     * * @param str The input string to be reversed.
+     * @return The reversed string.
+     */
+    public static String reverseStringUsingStack(String str) {
+        // Check if the input string is null
+        if (str == null) {
+            throw new IllegalArgumentException("Input string cannot be null");
+        }
+        Stack<Character> stack = new Stack<>();
+        StringBuilder reversedString = new StringBuilder();
+        // Check if the input string is empty
+        if (str.isEmpty()) {
+            return str;
+        }
+        // Push each character of the string onto the stack
+        for (char ch : str.toCharArray()) {
+            stack.push(ch);
+        }
+        // Pop each character from the stack and append to the StringBuilder
+        while (!stack.isEmpty()) {
+            reversedString.append(stack.pop());
+        }
+        return reversedString.toString();
+    }
 }
diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
index 08f5fb586d82..476765b00dfc 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
@@ -1,8 +1,10 @@
 package com.thealgorithms.strings;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -31,4 +33,15 @@ public void testReverseString2(String input, String expectedOutput) {
     public void testReverseString3(String input, String expectedOutput) {
         assertEquals(expectedOutput, ReverseString.reverse3(input));
     }
+
+    @ParameterizedTest
+    @MethodSource("testCases")
+    public void testReverseStringUsingStack(String input, String expectedOutput) {
+        assertEquals(expectedOutput, ReverseString.reverseStringUsingStack(input));
+    }
+
+    @Test
+    public void testReverseStringUsingStackWithNullInput() {
+        assertThrows(IllegalArgumentException.class, () -> ReverseString.reverseStringUsingStack(null));
+    }
 }

From 1652d80b7e4f8896f647ce59ff96d0583159c1b5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 8 Aug 2025 00:15:22 +0200
Subject: [PATCH 0924/1338] chore(deps-dev): bump org.assertj:assertj-core from
 3.27.3 to 3.27.4 (#6460)

Bumps [org.assertj:assertj-core](https://github.com/assertj/assertj) from 3.27.3 to 3.27.4.
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](https://github.com/assertj/assertj/compare/assertj-build-3.27.3...assertj-build-3.27.4)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-version: 3.27.4
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index eff6b935e0fc..c8f98d78a2d7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.27.3</assertj.version>
+        <assertj.version>3.27.4</assertj.version>
     </properties>
 
     <dependencyManagement>

From 4d28c88d6e7081abca50bf0c82b2f4bbe3f74d2e Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 8 Aug 2025 08:30:48 +0200
Subject: [PATCH 0925/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 10.26.1 to 11.0.0 (#6461)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.26.1 to 11.0.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-10.26.1...checkstyle-11.0.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 11.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index c8f98d78a2d7..0430df602313 100644
--- a/pom.xml
+++ b/pom.xml
@@ -113,7 +113,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.26.1</version>
+                    <version>11.0.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 57c6b033d1f7f9c5b2c97d57719f295866ddc8a0 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 12 Aug 2025 18:17:58 +0200
Subject: [PATCH 0926/1338] chore(deps): bump actions/checkout from 4 to 5 in
 /.github/workflows (#6464)

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 5.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v4...v5)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml              | 2 +-
 .github/workflows/clang-format-lint.yml  | 2 +-
 .github/workflows/codeql.yml             | 4 ++--
 .github/workflows/infer.yml              | 2 +-
 .github/workflows/project_structure.yml  | 2 +-
 .github/workflows/update-directorymd.yml | 2 +-
 6 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 3918e89533d5..8c21d1a09eb5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -8,7 +8,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Set up JDK
         uses: actions/setup-java@v4
         with:
diff --git a/.github/workflows/clang-format-lint.yml b/.github/workflows/clang-format-lint.yml
index 6f23946db999..ca014e115282 100644
--- a/.github/workflows/clang-format-lint.yml
+++ b/.github/workflows/clang-format-lint.yml
@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: DoozyX/clang-format-lint-action@v0.20
       with:
         source: './src'
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index d1133c251b65..5a9b4eaab1df 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -21,7 +21,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Set up JDK
         uses: actions/setup-java@v4
@@ -52,7 +52,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v3
diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index b0ee2fee8243..299534426e96 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -15,7 +15,7 @@ jobs:
   run_infer:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - name: Set up JDK
         uses: actions/setup-java@v4
diff --git a/.github/workflows/project_structure.yml b/.github/workflows/project_structure.yml
index dbc725655721..369541b5fbf7 100644
--- a/.github/workflows/project_structure.yml
+++ b/.github/workflows/project_structure.yml
@@ -15,7 +15,7 @@ jobs:
   check_structure:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: actions/setup-python@v5
         with:
           python-version: '3.13'
diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index 53ad221e7742..6692a884a867 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Run Directory Tree Generator
         uses: DenizAltunkapan/directory-tree-generator@v2

From 657f4334137e3c2513e053adb809c325e27735d1 Mon Sep 17 00:00:00 2001
From: ptzecher <72707951+ptzecher@users.noreply.github.com>
Date: Thu, 14 Aug 2025 20:42:51 +0300
Subject: [PATCH 0927/1338] Hopcroft karp Algorithm implementation and tests
 (#6465)

* Add Hopcroft-Karp algorithm and tests

* Adding wikipedia url for Algorithm

* fixing test issues

* remove unused field flagged by PMD
---
 .../com/thealgorithms/graph/HopcroftKarp.java | 103 ++++++++++++++
 .../thealgorithms/graph/HopcroftKarpTest.java | 133 ++++++++++++++++++
 2 files changed, 236 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/HopcroftKarp.java
 create mode 100644 src/test/java/com/thealgorithms/graph/HopcroftKarpTest.java

diff --git a/src/main/java/com/thealgorithms/graph/HopcroftKarp.java b/src/main/java/com/thealgorithms/graph/HopcroftKarp.java
new file mode 100644
index 000000000000..76f7f3eaa3a7
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/HopcroftKarp.java
@@ -0,0 +1,103 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Queue;
+
+/**
+ * Hopcroft–Karp algorithm for maximum bipartite matching.
+ *
+ * Left part: vertices [0,nLeft-1], Right part: [0,nRight-1].
+ * Adjacency list: for each left vertex u, list right vertices v it connects to.
+ *
+ * Time complexity: O(E * sqrt(V)).
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Hopcroft%E2%80%93Karp_algorithm">
+ *      Wikipedia: Hopcroft–Karp algorithm</a>
+ * @author ptzecher
+ */
+public class HopcroftKarp {
+
+    private final int nLeft;
+    private final List<List<Integer>> adj;
+
+    private final int[] pairU;
+    private final int[] pairV;
+    private final int[] dist;
+
+    public HopcroftKarp(int nLeft, int nRight, List<List<Integer>> adj) {
+        this.nLeft = nLeft;
+        this.adj = adj;
+
+        this.pairU = new int[nLeft];
+        this.pairV = new int[nRight];
+        this.dist = new int[nLeft];
+
+        Arrays.fill(pairU, -1);
+        Arrays.fill(pairV, -1);
+    }
+
+    /** Returns the size of the maximum matching. */
+    public int maxMatching() {
+        int matching = 0;
+        while (bfs()) {
+            for (int u = 0; u < nLeft; u++) {
+                if (pairU[u] == -1 && dfs(u)) {
+                    matching++;
+                }
+            }
+        }
+        return matching;
+    }
+
+    // BFS to build layers
+    private boolean bfs() {
+        Queue<Integer> queue = new ArrayDeque<>();
+        Arrays.fill(dist, -1);
+
+        for (int u = 0; u < nLeft; u++) {
+            if (pairU[u] == -1) {
+                dist[u] = 0;
+                queue.add(u);
+            }
+        }
+
+        boolean foundAugPath = false;
+        while (!queue.isEmpty()) {
+            int u = queue.poll();
+            for (int v : adj.get(u)) {
+                int matchedLeft = pairV[v];
+                if (matchedLeft == -1) {
+                    foundAugPath = true;
+                } else if (dist[matchedLeft] == -1) {
+                    dist[matchedLeft] = dist[u] + 1;
+                    queue.add(matchedLeft);
+                }
+            }
+        }
+        return foundAugPath;
+    }
+
+    // DFS to find augmenting paths within the BFS layering
+    private boolean dfs(int u) {
+        for (int v : adj.get(u)) {
+            int matchedLeft = pairV[v];
+            if (matchedLeft == -1 || (dist[matchedLeft] == dist[u] + 1 && dfs(matchedLeft))) {
+                pairU[u] = v;
+                pairV[v] = u;
+                return true;
+            }
+        }
+        dist[u] = -1;
+        return false;
+    }
+
+    public int[] getLeftMatches() {
+        return pairU.clone();
+    }
+
+    public int[] getRightMatches() {
+        return pairV.clone();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/HopcroftKarpTest.java b/src/test/java/com/thealgorithms/graph/HopcroftKarpTest.java
new file mode 100644
index 000000000000..2a5b1cdac795
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/HopcroftKarpTest.java
@@ -0,0 +1,133 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for Hopcroft–Karp algorithm.
+ *
+ * @author ptzecher
+ */
+class HopcroftKarpTest {
+
+    private static List<List<Integer>> adj(int nLeft) {
+        List<List<Integer>> g = new ArrayList<>(nLeft);
+        for (int i = 0; i < nLeft; i++) { // braces required by Checkstyle
+            g.add(new ArrayList<>());
+        }
+        return g;
+    }
+
+    @Test
+    @DisplayName("Empty graph has matching 0")
+    void emptyGraph() {
+        List<List<Integer>> g = adj(3);
+        HopcroftKarp hk = new HopcroftKarp(3, 4, g);
+        assertEquals(0, hk.maxMatching());
+    }
+
+    @Test
+    @DisplayName("Single edge gives matching 1")
+    void singleEdge() {
+        List<List<Integer>> g = adj(1);
+        g.get(0).add(0);
+        HopcroftKarp hk = new HopcroftKarp(1, 1, g);
+        assertEquals(1, hk.maxMatching());
+
+        int[] leftMatch = hk.getLeftMatches();
+        int[] rightMatch = hk.getRightMatches();
+        assertEquals(0, leftMatch[0]);
+        assertEquals(0, rightMatch[0]);
+    }
+
+    @Test
+    @DisplayName("Disjoint edges match perfectly")
+    void disjointEdges() {
+        // L0-R0, L1-R1, L2-R2
+        List<List<Integer>> g = adj(3);
+        g.get(0).add(0);
+        g.get(1).add(1);
+        g.get(2).add(2);
+
+        HopcroftKarp hk = new HopcroftKarp(3, 3, g);
+        assertEquals(3, hk.maxMatching());
+
+        int[] leftMatch = hk.getLeftMatches();
+        int[] rightMatch = hk.getRightMatches();
+        for (int i = 0; i < 3; i++) {
+            assertEquals(i, leftMatch[i]);
+            assertEquals(i, rightMatch[i]);
+        }
+    }
+
+    @Test
+    @DisplayName("Complete bipartite K(3,4) matches min(3,4)=3")
+    void completeK34() {
+        int nLeft = 3;
+        int nRight = 4; // split declarations
+        List<List<Integer>> g = adj(nLeft);
+        for (int u = 0; u < nLeft; u++) {
+            g.get(u).addAll(Arrays.asList(0, 1, 2, 3));
+        }
+        HopcroftKarp hk = new HopcroftKarp(nLeft, nRight, g);
+        assertEquals(3, hk.maxMatching());
+
+        // sanity: no two left vertices share the same matched right vertex
+        int[] leftMatch = hk.getLeftMatches();
+        boolean[] used = new boolean[nRight];
+        for (int u = 0; u < nLeft; u++) {
+            int v = leftMatch[u];
+            if (v != -1) {
+                assertFalse(used[v]);
+                used[v] = true;
+            }
+        }
+    }
+
+    @Test
+    @DisplayName("Rectangular, sparse graph")
+    void rectangularSparse() {
+        // Left: 5, Right: 2
+        // edges: L0-R0, L1-R1, L2-R0, L3-R1  (max matching = 2)
+        List<List<Integer>> g = adj(5);
+        g.get(0).add(0);
+        g.get(1).add(1);
+        g.get(2).add(0);
+        g.get(3).add(1);
+        // L4 isolated
+
+        HopcroftKarp hk = new HopcroftKarp(5, 2, g);
+        assertEquals(2, hk.maxMatching());
+
+        int[] leftMatch = hk.getLeftMatches();
+        int[] rightMatch = hk.getRightMatches();
+
+        // Check consistency: if leftMatch[u]=v then rightMatch[v]=u
+        for (int u = 0; u < 5; u++) {
+            int v = leftMatch[u];
+            if (v != -1) {
+                assertEquals(u, rightMatch[v]);
+            }
+        }
+    }
+
+    @Test
+    @DisplayName("Layering advantage case (short augmenting paths)")
+    void layeringAdvantage() {
+        // Left 4, Right 4
+        List<List<Integer>> g = adj(4);
+        g.get(0).addAll(Arrays.asList(0, 1));
+        g.get(1).addAll(Arrays.asList(1, 2));
+        g.get(2).addAll(Arrays.asList(2, 3));
+        g.get(3).addAll(Arrays.asList(0, 3));
+
+        HopcroftKarp hk = new HopcroftKarp(4, 4, g);
+        assertEquals(4, hk.maxMatching()); // perfect matching exists
+    }
+}

From 16345cba6db8657bf4b83fc7392920aa00a3e170 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Thu, 14 Aug 2025 21:29:37 +0200
Subject: [PATCH 0928/1338] Update DIRECTORY.md (#6468)

Co-authored-by: DenizAltunkapan <DenizAltunkapan@users.noreply.github.com>
---
 DIRECTORY.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 71d4b7d013cb..46e1d73a7d2a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -346,6 +346,7 @@
           - 📄 [Point](src/main/java/com/thealgorithms/geometry/Point.java)
         - 📁 **graph**
           - 📄 [ConstrainedShortestPath](src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java)
+          - 📄 [HopcroftKarp](src/main/java/com/thealgorithms/graph/HopcroftKarp.java)
           - 📄 [StronglyConnectedComponentOptimized](src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
           - 📄 [TravelingSalesman](src/main/java/com/thealgorithms/graph/TravelingSalesman.java)
         - 📁 **greedyalgorithms**
@@ -1051,6 +1052,7 @@
           - 📄 [PointTest](src/test/java/com/thealgorithms/geometry/PointTest.java)
         - 📁 **graph**
           - 📄 [ConstrainedShortestPathTest](src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java)
+          - 📄 [HopcroftKarpTest](src/test/java/com/thealgorithms/graph/HopcroftKarpTest.java)
           - 📄 [StronglyConnectedComponentOptimizedTest](src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)
           - 📄 [TravelingSalesmanTest](src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java)
         - 📁 **greedyalgorithms**

From 2dd6a137075a2f99db21e22d3cf921f7ce9d2df4 Mon Sep 17 00:00:00 2001
From: Stathis Veinoglou <115431071+StathisVeinoglou@users.noreply.github.com>
Date: Fri, 15 Aug 2025 19:41:52 +0300
Subject: [PATCH 0929/1338] Add DFS with parent-completion constraint for DAG
 traversal (#6467)

* Add DFS with parent-completion constraint for DAG traversal

* warning in PartitionProblem.java affecting tests

* added clang-format and updated javadoc

* optimized imports and rechecked camelCase format in tests

* removed .* import and made small visual change

* replaced a inline return with correct {} block

* Removed changed in PartitionProblem.java, Renamed class name to be straightforward about the implementation.Added full names instead of shortcuts, and included record.

* updated for clang format

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../graph/PredecessorConstrainedDfs.java      | 163 ++++++++++++++++++
 .../graph/PredecessorConstrainedDfsTest.java  |  90 ++++++++++
 2 files changed, 253 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/PredecessorConstrainedDfs.java
 create mode 100644 src/test/java/com/thealgorithms/graph/PredecessorConstrainedDfsTest.java

diff --git a/src/main/java/com/thealgorithms/graph/PredecessorConstrainedDfs.java b/src/main/java/com/thealgorithms/graph/PredecessorConstrainedDfs.java
new file mode 100644
index 000000000000..2cf4ed23c44f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/PredecessorConstrainedDfs.java
@@ -0,0 +1,163 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * DFS that visits a successor only when all its predecessors are already visited,
+ * emitting VISIT and SKIP events.
+ * <p>
+ *     This class includes a DFS variant that visits a successor only when all of its
+ *     predecessors have already been visited
+ * </p>
+ * <p>Related reading:
+ * <ul>
+ *   <li><a href="https://en.wikipedia.org/wiki/Topological_sorting">Topological sorting</a></li>
+ *   <li><a href="https://en.wikipedia.org/wiki/Depth-first_search">Depth-first search</a></li>
+ * </ul>
+ * </p>
+ */
+
+public final class PredecessorConstrainedDfs {
+
+    private PredecessorConstrainedDfs() {
+        // utility class
+    }
+
+    /** An event emitted by the traversal: either a VISIT with an order, or a SKIP with a note. */
+    public record TraversalEvent<T>(T node,
+        Integer order, // non-null for visit, null for skip
+        String note // non-null for skip, null for visit
+    ) {
+        public TraversalEvent {
+            Objects.requireNonNull(node);
+            // order and note can be null based on event type
+        }
+
+        /** A visit event with an increasing order (0,1,2,...) */
+        public static <T> TraversalEvent<T> visit(T node, int order) {
+            return new TraversalEvent<>(node, order, null);
+        }
+
+        /** A skip event with an explanatory note (e.g., not all parents visited yet). */
+        public static <T> TraversalEvent<T> skip(T node, String note) {
+            return new TraversalEvent<>(node, null, Objects.requireNonNull(note));
+        }
+
+        public boolean isVisit() {
+            return order != null;
+        }
+
+        public boolean isSkip() {
+            return order == null;
+        }
+
+        @Override
+        public String toString() {
+            return isVisit() ? "VISIT(" + node + ", order=" + order + ")" : "SKIP(" + node + ", " + note + ")";
+        }
+    }
+
+    /**
+     * DFS (recursive) that records the order of first visit starting at {@code start},
+     * but only recurses to a child when <b>all</b> its predecessors have been visited.
+     * If a child is encountered early (some parent unvisited), a SKIP event is recorded.
+     *
+     * <p>Equivalent idea to the Python pseudo in the user's description (with successors and predecessors),
+     * but implemented in Java and returning a sequence of {@link TraversalEvent}s.</p>
+     *
+     * @param successors adjacency list: for each node, its outgoing neighbors
+     * @param start start node
+     * @return immutable list of traversal events (VISITs with monotonically increasing order and SKIPs with messages)
+     * @throws IllegalArgumentException if {@code successors} is null
+     */
+    public static <T> List<TraversalEvent<T>> dfsRecursiveOrder(Map<T, List<T>> successors, T start) {
+        if (successors == null) {
+            throw new IllegalArgumentException("successors must not be null");
+        }
+        // derive predecessors once
+        Map<T, List<T>> predecessors = derivePredecessors(successors);
+        return dfsRecursiveOrder(successors, predecessors, start);
+    }
+
+    /**
+     * Same as {@link #dfsRecursiveOrder(Map, Object)} but with an explicit predecessors map.
+     */
+    public static <T> List<TraversalEvent<T>> dfsRecursiveOrder(Map<T, List<T>> successors, Map<T, List<T>> predecessors, T start) {
+
+        if (successors == null || predecessors == null) {
+            throw new IllegalArgumentException("successors and predecessors must not be null");
+        }
+        if (start == null) {
+            return List.of();
+        }
+        if (!successors.containsKey(start) && !appearsAnywhere(successors, start)) {
+            return List.of(); // start not present in graph
+        }
+
+        List<TraversalEvent<T>> events = new ArrayList<>();
+        Set<T> visited = new HashSet<>();
+        int[] order = {0};
+        dfs(start, successors, predecessors, visited, order, events);
+        return Collections.unmodifiableList(events);
+    }
+
+    private static <T> void dfs(T currentNode, Map<T, List<T>> successors, Map<T, List<T>> predecessors, Set<T> visited, int[] order, List<TraversalEvent<T>> result) {
+
+        if (!visited.add(currentNode)) {
+            return; // already visited
+        }
+        result.add(TraversalEvent.visit(currentNode, order[0]++)); // record visit and increment
+
+        for (T childNode : successors.getOrDefault(currentNode, List.of())) {
+            if (visited.contains(childNode)) {
+                continue;
+            }
+            if (allParentsVisited(childNode, visited, predecessors)) {
+                dfs(childNode, successors, predecessors, visited, order, result);
+            } else {
+                result.add(TraversalEvent.skip(childNode, "⛔ Skipping " + childNode + ": not all parents are visited yet."));
+                // do not mark visited; it may be visited later from another parent
+            }
+        }
+    }
+
+    private static <T> boolean allParentsVisited(T node, Set<T> visited, Map<T, List<T>> predecessors) {
+        for (T parent : predecessors.getOrDefault(node, List.of())) {
+            if (!visited.contains(parent)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private static <T> boolean appearsAnywhere(Map<T, List<T>> successors, T node) {
+        if (successors.containsKey(node)) {
+            return true;
+        }
+        for (List<T> neighbours : successors.values()) {
+            if (neighbours != null && neighbours.contains(node)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static <T> Map<T, List<T>> derivePredecessors(Map<T, List<T>> successors) {
+        Map<T, List<T>> predecessors = new HashMap<>();
+        // ensure keys exist for all nodes appearing anywhere
+        for (Map.Entry<T, List<T>> entry : successors.entrySet()) {
+            predecessors.computeIfAbsent(entry.getKey(), key -> new ArrayList<>());
+            for (T childNode : entry.getValue()) {
+                predecessors.computeIfAbsent(childNode, key -> new ArrayList<>()).add(entry.getKey());
+            }
+        }
+        return predecessors;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/PredecessorConstrainedDfsTest.java b/src/test/java/com/thealgorithms/graph/PredecessorConstrainedDfsTest.java
new file mode 100644
index 000000000000..e2c6d468768f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/PredecessorConstrainedDfsTest.java
@@ -0,0 +1,90 @@
+package com.thealgorithms.graph;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import com.thealgorithms.graph.PredecessorConstrainedDfs.TraversalEvent;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import org.junit.jupiter.api.Test;
+
+class PredecessorConstrainedDfsTest {
+
+    // A -> B, A -> C, B -> D, C -> D   (classic diamond)
+    private static Map<String, List<String>> diamond() {
+        Map<String, List<String>> g = new LinkedHashMap<>();
+        g.put("A", List.of("B", "C"));
+        g.put("B", List.of("D"));
+        g.put("C", List.of("D"));
+        g.put("D", List.of());
+        return g;
+    }
+
+    @Test
+    void dfsRecursiveOrderEmitsSkipUntilAllParentsVisited() {
+        List<TraversalEvent<String>> events = PredecessorConstrainedDfs.dfsRecursiveOrder(diamond(), "A");
+
+        // Expect visits in order and a skip for first time we meet D (via B) before C is visited.
+        var visits = events.stream().filter(TraversalEvent::isVisit).toList();
+        var skips = events.stream().filter(TraversalEvent::isSkip).toList();
+
+        // Visits should be A(0), B(1), C(2), D(3) in some deterministic order given adjacency
+        assertThat(visits).hasSize(4);
+        assertThat(visits.get(0).node()).isEqualTo("A");
+        assertThat(visits.get(0).order()).isEqualTo(0);
+        assertThat(visits.get(1).node()).isEqualTo("B");
+        assertThat(visits.get(1).order()).isEqualTo(1);
+        assertThat(visits.get(2).node()).isEqualTo("C");
+        assertThat(visits.get(2).order()).isEqualTo(2);
+        assertThat(visits.get(3).node()).isEqualTo("D");
+        assertThat(visits.get(3).order()).isEqualTo(3);
+
+        // One skip when we first encountered D from B (before C was visited)
+        assertThat(skips).hasSize(1);
+        assertThat(skips.get(0).node()).isEqualTo("D");
+        assertThat(skips.get(0).note()).contains("not all parents");
+    }
+
+    @Test
+    void returnsEmptyWhenStartNotInGraph() {
+        Map<Integer, List<Integer>> graph = Map.of(1, List.of(2), 2, List.of(1));
+        assertThat(PredecessorConstrainedDfs.dfsRecursiveOrder(graph, 99)).isEmpty();
+    }
+
+    @Test
+    void nullSuccessorsThrows() {
+        assertThrows(IllegalArgumentException.class, () -> PredecessorConstrainedDfs.dfsRecursiveOrder(null, "A"));
+    }
+
+    @Test
+    void worksWithExplicitPredecessors() {
+        Map<Integer, List<Integer>> successors = new HashMap<>();
+        successors.put(10, List.of(20));
+        successors.put(20, List.of(30));
+        successors.put(30, List.of());
+
+        Map<Integer, List<Integer>> predecessors = new HashMap<>();
+        predecessors.put(10, List.of());
+        predecessors.put(20, List.of(10));
+        predecessors.put(30, List.of(20));
+
+        var events = PredecessorConstrainedDfs.dfsRecursiveOrder(successors, predecessors, 10);
+        var visitNodes = events.stream().filter(TraversalEvent::isVisit).map(TraversalEvent::node).toList();
+        assertThat(visitNodes).containsExactly(10, 20, 30);
+    }
+
+    @Test
+    void cycleProducesSkipsButNoInfiniteRecursion() {
+        Map<String, List<String>> successors = new LinkedHashMap<>();
+        successors.put("X", List.of("Y"));
+        successors.put("Y", List.of("X")); // 2-cycle
+
+        var events = PredecessorConstrainedDfs.dfsRecursiveOrder(successors, "X");
+        // Only X is visited; encountering Y from X causes skip because Y's parent X is visited,
+        // but when recursing to Y we'd hit back to X (already visited) and stop; no infinite loop.
+        assertThat(events.stream().anyMatch(TraversalEvent::isVisit)).isTrue();
+        assertThat(events.stream().filter(TraversalEvent::isVisit).map(TraversalEvent::node)).contains("X");
+    }
+}

From b0d7c06314ab845e930ab73af20797a12c79f44f Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Fri, 15 Aug 2025 20:32:28 +0200
Subject: [PATCH 0930/1338] Update DIRECTORY.md (#6469)

Co-authored-by: DenizAltunkapan <DenizAltunkapan@users.noreply.github.com>
---
 DIRECTORY.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 46e1d73a7d2a..5861f088cc2f 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -347,6 +347,7 @@
         - 📁 **graph**
           - 📄 [ConstrainedShortestPath](src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java)
           - 📄 [HopcroftKarp](src/main/java/com/thealgorithms/graph/HopcroftKarp.java)
+          - 📄 [PredecessorConstrainedDfs](src/main/java/com/thealgorithms/graph/PredecessorConstrainedDfs.java)
           - 📄 [StronglyConnectedComponentOptimized](src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
           - 📄 [TravelingSalesman](src/main/java/com/thealgorithms/graph/TravelingSalesman.java)
         - 📁 **greedyalgorithms**
@@ -1053,6 +1054,7 @@
         - 📁 **graph**
           - 📄 [ConstrainedShortestPathTest](src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java)
           - 📄 [HopcroftKarpTest](src/test/java/com/thealgorithms/graph/HopcroftKarpTest.java)
+          - 📄 [PredecessorConstrainedDfsTest](src/test/java/com/thealgorithms/graph/PredecessorConstrainedDfsTest.java)
           - 📄 [StronglyConnectedComponentOptimizedTest](src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)
           - 📄 [TravelingSalesmanTest](src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java)
         - 📁 **greedyalgorithms**

From 9f0dd37c5ea159004355d301057f4a9eaebba987 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 15 Aug 2025 23:18:53 +0200
Subject: [PATCH 0931/1338] chore(deps-dev): bump org.mockito:mockito-core from
 5.18.0 to 5.19.0 (#6471)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.18.0 to 5.19.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.18.0...v5.19.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.19.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 0430df602313..f283cabf9b02 100644
--- a/pom.xml
+++ b/pom.xml
@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.18.0</version>
+            <version>5.19.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 6c24d27b03bdc17e28c210901b34982fdb704f49 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Mon, 18 Aug 2025 22:28:19 +0200
Subject: [PATCH 0932/1338] Move methods from others to correct packages
 (#6475)

refactor: Move methods from `others` package to their respective packages
---
 .../{others => slidingwindow}/MaximumSlidingWindow.java         | 2 +-
 .../{others => strings}/RemoveDuplicateFromString.java          | 2 +-
 .../{others => slidingwindow}/MaximumSlidingWindowTest.java     | 2 +-
 .../{others => strings}/RemoveDuplicateFromStringTest.java      | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)
 rename src/main/java/com/thealgorithms/{others => slidingwindow}/MaximumSlidingWindow.java (97%)
 rename src/main/java/com/thealgorithms/{others => strings}/RemoveDuplicateFromString.java (96%)
 rename src/test/java/com/thealgorithms/{others => slidingwindow}/MaximumSlidingWindowTest.java (97%)
 rename src/test/java/com/thealgorithms/{others => strings}/RemoveDuplicateFromStringTest.java (96%)

diff --git a/src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java b/src/main/java/com/thealgorithms/slidingwindow/MaximumSlidingWindow.java
similarity index 97%
rename from src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java
rename to src/main/java/com/thealgorithms/slidingwindow/MaximumSlidingWindow.java
index d0b2c2a0e56d..f52ba28fd8b5 100644
--- a/src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java
+++ b/src/main/java/com/thealgorithms/slidingwindow/MaximumSlidingWindow.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.slidingwindow;
 
 import java.util.ArrayDeque;
 import java.util.Deque;
diff --git a/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java b/src/main/java/com/thealgorithms/strings/RemoveDuplicateFromString.java
similarity index 96%
rename from src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java
rename to src/main/java/com/thealgorithms/strings/RemoveDuplicateFromString.java
index 5b6466f6fa07..84d4fd8f72ce 100644
--- a/src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java
+++ b/src/main/java/com/thealgorithms/strings/RemoveDuplicateFromString.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 /**
  * @author Varun Upadhyay (https://github.com/varunu28)
diff --git a/src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java b/src/test/java/com/thealgorithms/slidingwindow/MaximumSlidingWindowTest.java
similarity index 97%
rename from src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java
rename to src/test/java/com/thealgorithms/slidingwindow/MaximumSlidingWindowTest.java
index 9209136a5af3..a2d233b6063b 100644
--- a/src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java
+++ b/src/test/java/com/thealgorithms/slidingwindow/MaximumSlidingWindowTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.slidingwindow;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
diff --git a/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java b/src/test/java/com/thealgorithms/strings/RemoveDuplicateFromStringTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java
rename to src/test/java/com/thealgorithms/strings/RemoveDuplicateFromStringTest.java
index 3401a51c56c9..de912bbfdb18 100644
--- a/src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java
+++ b/src/test/java/com/thealgorithms/strings/RemoveDuplicateFromStringTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.strings;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;

From 0ff2c06a475bb224e95d581d63cf03509f31c0f6 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 19 Aug 2025 21:24:04 +0200
Subject: [PATCH 0933/1338] chore(deps): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.6.12 to 7.6.13 (#6477)

* chore(deps): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.6.12 to 7.6.13.
- [Commits](https://github.com/mebigfatguy/fb-contrib/compare/v7.6.12...v7.6.13)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.6.13
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

* fix: exclude `SPP_FIELD_COULD_BE_STATIC`

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 pom.xml              | 2 +-
 spotbugs-exclude.xml | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index f283cabf9b02..9321c35996f7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -128,7 +128,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.12</version>
+                            <version>7.6.13</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index bcc053611de6..efd7f9d12a35 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -198,6 +198,9 @@
     <Match>
         <Bug pattern="BAS_BLOATED_ASSIGNMENT_SCOPE" />
     </Match>
+    <Match>
+        <Bug pattern="SPP_FIELD_COULD_BE_STATIC" />
+    </Match>
     <!-- find-sec-bugs -->
     <Match>
         <Bug pattern="PREDICTABLE_RANDOM" />

From 3f195c2c89714fc3aa22e44546b8c869cea4b127 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Thu, 21 Aug 2025 20:03:42 +0200
Subject: [PATCH 0934/1338] Update DIRECTORY.md (#6476)

Co-authored-by: vil02 <vil02@users.noreply.github.com>
---
 DIRECTORY.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 5861f088cc2f..c51396459476 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -547,7 +547,6 @@
           - 📄 [LowestBasePalindrome](src/main/java/com/thealgorithms/others/LowestBasePalindrome.java)
           - 📄 [Luhn](src/main/java/com/thealgorithms/others/Luhn.java)
           - 📄 [Mandelbrot](src/main/java/com/thealgorithms/others/Mandelbrot.java)
-          - 📄 [MaximumSlidingWindow](src/main/java/com/thealgorithms/others/MaximumSlidingWindow.java)
           - 📄 [MaximumSumOfDistinctSubarraysWithLengthK](src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java)
           - 📄 [MemoryManagementAlgorithms](src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java)
           - 📄 [MiniMaxAlgorithm](src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java)
@@ -556,7 +555,6 @@
           - 📄 [PerlinNoise](src/main/java/com/thealgorithms/others/PerlinNoise.java)
           - 📄 [PrintAMatrixInSpiralOrder](src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java)
           - 📄 [QueueUsingTwoStacks](src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java)
-          - 📄 [RemoveDuplicateFromString](src/main/java/com/thealgorithms/others/RemoveDuplicateFromString.java)
           - 📄 [ReverseStackUsingRecursion](src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
           - 📄 [SkylineProblem](src/main/java/com/thealgorithms/others/SkylineProblem.java)
           - 📄 [TwoPointers](src/main/java/com/thealgorithms/others/TwoPointers.java)
@@ -640,6 +638,7 @@
           - 📄 [LongestSubarrayWithSumLessOrEqualToK](src/main/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToK.java)
           - 📄 [LongestSubstringWithoutRepeatingCharacters](src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java)
           - 📄 [MaxSumKSizeSubarray](src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java)
+          - 📄 [MaximumSlidingWindow](src/main/java/com/thealgorithms/slidingwindow/MaximumSlidingWindow.java)
           - 📄 [MinSumKSizeSubarray](src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java)
           - 📄 [ShortestCoprimeSegment](src/main/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegment.java)
         - 📁 **sorts**
@@ -738,6 +737,7 @@
           - 📄 [Pangram](src/main/java/com/thealgorithms/strings/Pangram.java)
           - 📄 [PermuteString](src/main/java/com/thealgorithms/strings/PermuteString.java)
           - 📄 [RabinKarp](src/main/java/com/thealgorithms/strings/RabinKarp.java)
+          - 📄 [RemoveDuplicateFromString](src/main/java/com/thealgorithms/strings/RemoveDuplicateFromString.java)
           - 📄 [ReturnSubsequence](src/main/java/com/thealgorithms/strings/ReturnSubsequence.java)
           - 📄 [ReverseString](src/main/java/com/thealgorithms/strings/ReverseString.java)
           - 📄 [ReverseStringRecursive](src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java)
@@ -1222,13 +1222,11 @@
           - 📄 [LineSweepTest](src/test/java/com/thealgorithms/others/LineSweepTest.java)
           - 📄 [LinkListSortTest](src/test/java/com/thealgorithms/others/LinkListSortTest.java)
           - 📄 [LowestBasePalindromeTest](src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java)
-          - 📄 [MaximumSlidingWindowTest](src/test/java/com/thealgorithms/others/MaximumSlidingWindowTest.java)
           - 📄 [MaximumSumOfDistinctSubarraysWithLengthKTest](src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java)
           - 📄 [NewManShanksPrimeTest](src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java)
           - 📄 [NextFitTest](src/test/java/com/thealgorithms/others/NextFitTest.java)
           - 📄 [PasswordGenTest](src/test/java/com/thealgorithms/others/PasswordGenTest.java)
           - 📄 [QueueUsingTwoStacksTest](src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java)
-          - 📄 [RemoveDuplicateFromStringTest](src/test/java/com/thealgorithms/others/RemoveDuplicateFromStringTest.java)
           - 📄 [ReverseStackUsingRecursionTest](src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
           - 📄 [SkylineProblemTest](src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
           - 📄 [TestPrintMatrixInSpiralOrder](src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
@@ -1314,6 +1312,7 @@
           - 📄 [LongestSubarrayWithSumLessOrEqualToKTest](src/test/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToKTest.java)
           - 📄 [LongestSubstringWithoutRepeatingCharactersTest](src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java)
           - 📄 [MaxSumKSizeSubarrayTest](src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java)
+          - 📄 [MaximumSlidingWindowTest](src/test/java/com/thealgorithms/slidingwindow/MaximumSlidingWindowTest.java)
           - 📄 [MinSumKSizeSubarrayTest](src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java)
           - 📄 [ShortestCoprimeSegmentTest](src/test/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegmentTest.java)
         - 📁 **sorts**
@@ -1408,6 +1407,7 @@
           - 📄 [PalindromeTest](src/test/java/com/thealgorithms/strings/PalindromeTest.java)
           - 📄 [PangramTest](src/test/java/com/thealgorithms/strings/PangramTest.java)
           - 📄 [PermuteStringTest](src/test/java/com/thealgorithms/strings/PermuteStringTest.java)
+          - 📄 [RemoveDuplicateFromStringTest](src/test/java/com/thealgorithms/strings/RemoveDuplicateFromStringTest.java)
           - 📄 [ReturnSubsequenceTest](src/test/java/com/thealgorithms/strings/ReturnSubsequenceTest.java)
           - 📄 [ReverseStringRecursiveTest](src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java)
           - 📄 [ReverseStringTest](src/test/java/com/thealgorithms/strings/ReverseStringTest.java)

From 3961b1dab9b874c2396e0f6c038a586e88b65e75 Mon Sep 17 00:00:00 2001
From: Vicky <vvickyar25@gmail.com>
Date: Fri, 22 Aug 2025 11:11:36 +0530
Subject: [PATCH 0935/1338] fix: revert ReverseStack deletion and verify
 linting (#6474) (#6494)

* fix: revert ReverseStack deletions and ensure lint compliance

* Fix formatting for ReverseStack and test files

* Delete ReverseStackUsingRecursion and its test as requested

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../datastructures/stacks/ReverseStack.java   |  3 +
 .../others/ReverseStackUsingRecursion.java    | 44 --------------
 .../stacks/ReverseStackTest.java              |  6 ++
 .../ReverseStackUsingRecursionTest.java       | 58 -------------------
 4 files changed, 9 insertions(+), 102 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
 delete mode 100644 src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java b/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
index e9de14b53302..d87f5f4ea86a 100644
--- a/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
+++ b/src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
@@ -38,6 +38,9 @@ private ReverseStack() {
      * @param stack the stack to reverse; should not be null
      */
     public static void reverseStack(Stack<Integer> stack) {
+        if (stack == null) {
+            throw new IllegalArgumentException("Stack cannot be null");
+        }
         if (stack.isEmpty()) {
             return;
         }
diff --git a/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java b/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
deleted file mode 100644
index de36673512a0..000000000000
--- a/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
+++ /dev/null
@@ -1,44 +0,0 @@
-package com.thealgorithms.others;
-
-import java.util.Stack;
-
-/**
- * Class that provides methods to reverse a stack using recursion.
- */
-public final class ReverseStackUsingRecursion {
-    private ReverseStackUsingRecursion() {
-    }
-
-    /**
-     * Reverses the elements of the given stack using recursion.
-     *
-     * @param stack the stack to be reversed
-     * @throws IllegalArgumentException if the stack is null
-     */
-    public static void reverse(Stack<Integer> stack) {
-        if (stack == null) {
-            throw new IllegalArgumentException("Stack cannot be null");
-        }
-        if (!stack.isEmpty()) {
-            int topElement = stack.pop();
-            reverse(stack);
-            insertAtBottom(stack, topElement);
-        }
-    }
-
-    /**
-     * Inserts an element at the bottom of the given stack.
-     *
-     * @param stack    the stack where the element will be inserted
-     * @param element  the element to be inserted at the bottom
-     */
-    private static void insertAtBottom(Stack<Integer> stack, int element) {
-        if (stack.isEmpty()) {
-            stack.push(element);
-        } else {
-            int topElement = stack.pop();
-            insertAtBottom(stack, element);
-            stack.push(topElement);
-        }
-    }
-}
diff --git a/src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java b/src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java
index 2e2bc5adae3a..a4e781c84127 100644
--- a/src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.stacks;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.Stack;
@@ -8,6 +9,11 @@
 
 class ReverseStackTest {
 
+    @Test
+    void testReverseNullStack() {
+        assertThrows(IllegalArgumentException.class, () -> ReverseStack.reverseStack(null), "Reversing a null stack should throw an IllegalArgumentException.");
+    }
+
     @Test
     void testReverseEmptyStack() {
         Stack<Integer> stack = new Stack<>();
diff --git a/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java b/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java
deleted file mode 100644
index 23b99ae87d35..000000000000
--- a/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java
+++ /dev/null
@@ -1,58 +0,0 @@
-package com.thealgorithms.others;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
-import java.util.Stack;
-import org.junit.jupiter.api.Test;
-
-public class ReverseStackUsingRecursionTest {
-
-    @Test
-    void testReverseWithMultipleElements() {
-        Stack<Integer> stack = new Stack<>();
-        for (int i = 0; i < 5; i++) {
-            stack.push(i);
-        }
-
-        ReverseStackUsingRecursion.reverse(stack);
-
-        for (int i = 0; i < 5; i++) {
-            assertEquals(i, stack.pop());
-        }
-        assertTrue(stack.isEmpty());
-    }
-
-    @Test
-    void testReverseWithSingleElement() {
-        Stack<Integer> stack = new Stack<>();
-        stack.push(1);
-
-        ReverseStackUsingRecursion.reverse(stack);
-
-        assertEquals(1, stack.pop());
-        assertTrue(stack.isEmpty());
-    }
-
-    @Test
-    void testReverseWithEmptyStack() {
-        Stack<Integer> stack = new Stack<>();
-
-        ReverseStackUsingRecursion.reverse(stack);
-
-        assertTrue(stack.isEmpty());
-    }
-
-    @Test
-    void testReverseWithNullStack() {
-        Stack<Integer> stack = null;
-
-        Exception exception = assertThrows(IllegalArgumentException.class, () -> ReverseStackUsingRecursion.reverse(stack));
-
-        String expectedMessage = "Stack cannot be null";
-        String actualMessage = exception.getMessage();
-
-        assertTrue(actualMessage.contains(expectedMessage));
-    }
-}

From c04607536f90c1fe97d712dcc84dca989fbbb592 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 22 Aug 2025 07:51:22 +0200
Subject: [PATCH 0936/1338] chore(deps): bump actions/setup-java from 4 to 5 in
 /.github/workflows (#6499)

Bumps [actions/setup-java](https://github.com/actions/setup-java) from 4 to 5.
- [Release notes](https://github.com/actions/setup-java/releases)
- [Commits](https://github.com/actions/setup-java/compare/v4...v5)

---
updated-dependencies:
- dependency-name: actions/setup-java
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .github/workflows/build.yml  | 2 +-
 .github/workflows/codeql.yml | 2 +-
 .github/workflows/infer.yml  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 8c21d1a09eb5..39bde758d68e 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@v5
       - name: Set up JDK
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@v5
         with:
           java-version: 21
           distribution: 'temurin'
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 5a9b4eaab1df..ef4953afc954 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -24,7 +24,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Set up JDK
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@v5
         with:
           java-version: 21
           distribution: 'temurin'
diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index 299534426e96..3df7c4b1fc9e 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -18,7 +18,7 @@ jobs:
       - uses: actions/checkout@v5
 
       - name: Set up JDK
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@v5
         with:
           java-version: 21
           distribution: 'temurin'

From e78d53d747b12f72d7394484b1433783e7e55fc2 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 25 Aug 2025 21:22:15 +0200
Subject: [PATCH 0937/1338] chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.3.2 to 4.9.4.0 (#6498)

* chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.3.2 to 4.9.4.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.3.2...spotbugs-maven-plugin-4.9.4.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.4.0
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

* fix: exclude `SF_SWITCH_FALLTHROUGH`

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 pom.xml              | 2 +-
 spotbugs-exclude.xml | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 9321c35996f7..e365be3f3f96 100644
--- a/pom.xml
+++ b/pom.xml
@@ -120,7 +120,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.3.2</version>
+                <version>4.9.4.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index efd7f9d12a35..4f327a443781 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -86,6 +86,9 @@
     <Match>
         <Bug pattern="AT_STALE_THREAD_WRITE_OF_PRIMITIVE" />
     </Match>
+    <Match>
+        <Bug pattern="SF_SWITCH_FALLTHROUGH" />
+    </Match>
     <!-- fb-contrib -->
     <Match>
         <Bug pattern="LSC_LITERAL_STRING_COMPARISON" />

From 27ada8a649cbe8eabdfe345c2f262da9179251d1 Mon Sep 17 00:00:00 2001
From: Nihar Kakani <niharkakani@gmail.com>
Date: Wed, 27 Aug 2025 20:29:04 +0530
Subject: [PATCH 0938/1338] Migrate recursive reverse string method and tests
 to ReverseString (#6504)

* Migrate recursive reverse string method and tests to ReverseString

- Moved recursive reverse method from ReverseStringRecursive.java to ReverseString.java
- Moved tests from ReverseStringRecursiveTest.java to ReverseStringTest.java
- Deleted old ReverseStringRecursive files

* Fix formatting for ReverseStringTest.java as per clang-format linter
---
 .../thealgorithms/strings/ReverseString.java  | 13 ++++++++++++
 .../strings/ReverseStringRecursive.java       | 21 -------------------
 .../strings/ReverseStringRecursiveTest.java   | 16 --------------
 .../strings/ReverseStringTest.java            |  9 ++++++++
 4 files changed, 22 insertions(+), 37 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java
 delete mode 100644 src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java

diff --git a/src/main/java/com/thealgorithms/strings/ReverseString.java b/src/main/java/com/thealgorithms/strings/ReverseString.java
index 996aa68bb307..7b918ebe1a59 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseString.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseString.java
@@ -86,4 +86,17 @@ public static String reverseStringUsingStack(String str) {
         }
         return reversedString.toString();
     }
+
+    /**
+     * Reverse the String using Recursion
+     * @param str string to be reversed
+     * @return reversed string
+     */
+    public static String reverseStringUsingRecursion(String str) {
+        if (str.isEmpty()) {
+            return str;
+        } else {
+            return reverseStringUsingRecursion(str.substring(1)) + str.charAt(0);
+        }
+    }
 }
diff --git a/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java b/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java
deleted file mode 100644
index 817b0a8ccd09..000000000000
--- a/src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java
+++ /dev/null
@@ -1,21 +0,0 @@
-package com.thealgorithms.strings;
-
-/**
- * Reverse String using Recursion
- */
-public final class ReverseStringRecursive {
-    private ReverseStringRecursive() {
-    }
-
-    /**
-     * @param str string to be reversed
-     * @return reversed string
-     */
-    public static String reverse(String str) {
-        if (str.isEmpty()) {
-            return str;
-        } else {
-            return reverse(str.substring(1)) + str.charAt(0);
-        }
-    }
-}
diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java
deleted file mode 100644
index 19daa61f48ca..000000000000
--- a/src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java
+++ /dev/null
@@ -1,16 +0,0 @@
-package com.thealgorithms.strings;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.CsvSource;
-
-public class ReverseStringRecursiveTest {
-    @ParameterizedTest
-    @CsvSource({"'Hello World', 'dlroW olleH'", "'helloworld', 'dlrowolleh'", "'123456789', '987654321'", "'', ''", "'A', 'A'", "'!123 ABC xyz!', '!zyx CBA 321!'", "'Abc 123 Xyz', 'zyX 321 cbA'", "'12.34,56;78:90', '09:87;65,43.21'", "'abcdEFGHiJKL', 'LKJiHGFEdcba'",
-        "'MixOf123AndText!', '!txeTdnA321fOxiM'"})
-    public void
-    testReverseString(String input, String expectedOutput) {
-        assertEquals(expectedOutput, ReverseStringRecursive.reverse(input));
-    }
-}
diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
index 476765b00dfc..c50f92c1a008 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
@@ -7,6 +7,7 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.CsvSource;
 import org.junit.jupiter.params.provider.MethodSource;
 
 public class ReverseStringTest {
@@ -44,4 +45,12 @@ public void testReverseStringUsingStack(String input, String expectedOutput) {
     public void testReverseStringUsingStackWithNullInput() {
         assertThrows(IllegalArgumentException.class, () -> ReverseString.reverseStringUsingStack(null));
     }
+
+    @ParameterizedTest
+    @CsvSource({"'Hello World', 'dlroW olleH'", "'helloworld', 'dlrowolleh'", "'123456789', '987654321'", "'', ''", "'A', 'A'", "'!123 ABC xyz!', '!zyx CBA 321!'", "'Abc 123 Xyz', 'zyX 321 cbA'", "'12.34,56;78:90', '09:87;65,43.21'", "'abcdEFGHiJKL', 'LKJiHGFEdcba'",
+        "'MixOf123AndText!', '!txeTdnA321fOxiM'"})
+    public void
+    testReverseStringUsingRecursion(String input, String expectedOutput) {
+        assertEquals(expectedOutput, ReverseString.reverseStringUsingRecursion(input));
+    }
 }

From 79dc0b42a02430261110a0f7cd32caa87bfe24b3 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 30 Aug 2025 09:35:06 +0200
Subject: [PATCH 0939/1338] chore: remove @vil02 from `CODEOWNERS` (#6512)

---
 .github/CODEOWNERS | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 9a0617e18a06..f41af80a3459 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1 +1 @@
-* @DenizAltunkapan @yanglbme @vil02 @alxkm
+* @DenizAltunkapan @yanglbme @alxkm

From fe02c481bd582b86dafba4383812eea2d7d97d9e Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 3 Sep 2025 18:51:24 +0200
Subject: [PATCH 0940/1338] chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.4.0 to 4.9.4.1 (#6515)

chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.4.0 to 4.9.4.1.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.4.0...spotbugs-maven-plugin-4.9.4.1)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.4.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index e365be3f3f96..417fa49a6bb2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -120,7 +120,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.4.0</version>
+                <version>4.9.4.1</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From d09180e66a4967e1f4cc8991dbd7ba30e1996e74 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 3 Sep 2025 19:00:22 +0200
Subject: [PATCH 0941/1338] chore(deps): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.6.13 to 7.6.14 (#6517)

chore(deps): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.6.13 to 7.6.14.
- [Commits](https://github.com/mebigfatguy/fb-contrib/compare/v7.6.13...v7.6.14)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.6.14
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 417fa49a6bb2..e9714fb3654e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -128,7 +128,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.13</version>
+                            <version>7.6.14</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

From 1393f5ea6b974c62086fc9eee21235c8c1efd10b Mon Sep 17 00:00:00 2001
From: Priyansh <142749036+TIWARIPRIYANSH@users.noreply.github.com>
Date: Wed, 3 Sep 2025 22:35:12 +0530
Subject: [PATCH 0942/1338] Added-> DisjointUnion Set by Size (#6514)

* Added-> DisjointUnion Set by Size

* Add tests for DisjointSetUnionBySize

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../DisjointSetUnionBySize.java               |  83 ++++++++++
 .../DisjointSetUnionBySizeTest.java           | 146 ++++++++++++++++++
 2 files changed, 229 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionBySize.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionBySizeTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionBySize.java b/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionBySize.java
new file mode 100644
index 000000000000..71951f67dfc8
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionBySize.java
@@ -0,0 +1,83 @@
+package com.thealgorithms.datastructures.disjointsetunion;
+
+/**
+ * Disjoint Set Union (DSU) with Union by Size.
+ * This data structure tracks a set of elements partitioned into disjoint (non-overlapping) subsets.
+ * It supports two primary operations efficiently:
+ *
+ * <ul>
+ *     <li>Find: Determine which subset a particular element belongs to.</li>
+ *     <li>Union: Merge two subsets into a single subset using union by size.</li>
+ * </ul>
+ *
+ * Union by size always attaches the smaller tree under the root of the larger tree.
+ * This helps keep the tree shallow, improving the efficiency of find operations.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Disjoint-set_data_structure">Disjoint Set Union (Wikipedia)</a>
+ */
+public class DisjointSetUnionBySize<T> {
+    /**
+     * Node class for DSU by size.
+     * Each node keeps track of its parent and the size of the set it represents.
+     */
+    public static class Node<T> {
+        public T value;
+        public Node<T> parent;
+        public int size; // size of the set
+
+        public Node(T value) {
+            this.value = value;
+            this.parent = this;
+            this.size = 1; // initially, the set size is 1
+        }
+    }
+
+    /**
+     * Creates a new disjoint set containing the single specified element.
+     * @param value the element to be placed in a new singleton set
+     * @return a node representing the new set
+     */
+    public Node<T> makeSet(final T value) {
+        return new Node<>(value);
+    }
+
+    /**
+     * Finds and returns the representative (root) of the set containing the given node.
+     * This method applies path compression to flatten the tree structure for future efficiency.
+     * @param node the node whose set representative is to be found
+     * @return the representative (root) node of the set
+     */
+    public Node<T> findSet(Node<T> node) {
+        if (node != node.parent) {
+            node.parent = findSet(node.parent); // path compression
+        }
+        return node.parent;
+    }
+
+    /**
+     * Merges the sets containing the two given nodes using union by size.
+     * The root of the smaller set is attached to the root of the larger set.
+     * @param x a node in the first set
+     * @param y a node in the second set
+     */
+    public void unionSets(Node<T> x, Node<T> y) {
+        Node<T> rootX = findSet(x);
+        Node<T> rootY = findSet(y);
+
+        if (rootX == rootY) {
+            return; // They are already in the same set
+        }
+        // Union by size: attach smaller tree under the larger one
+        if (rootX.size < rootY.size) {
+            rootX.parent = rootY;
+            rootY.size += rootX.size; // update size
+        } else {
+            rootY.parent = rootX;
+            rootX.size += rootY.size; // update size
+        }
+    }
+}
+// This implementation uses union by size instead of union by rank.
+// The size field tracks the number of elements in each set.
+// When two sets are merged, the smaller set is always attached to the larger set's root.
+// This helps keep the tree shallow and improves the efficiency of find operations.
diff --git a/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionBySizeTest.java b/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionBySizeTest.java
new file mode 100644
index 000000000000..71dade9796dc
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionBySizeTest.java
@@ -0,0 +1,146 @@
+package com.thealgorithms.datastructures.disjointsetunion;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import org.junit.jupiter.api.Test;
+
+public class DisjointSetUnionBySizeTest {
+
+    @Test
+    public void testMakeSet() {
+        DisjointSetUnionBySize<Integer> dsu = new DisjointSetUnionBySize<>();
+        DisjointSetUnionBySize.Node<Integer> node = dsu.makeSet(1);
+        assertNotNull(node);
+        assertEquals(node, node.parent);
+        assertEquals(1, node.size);
+    }
+
+    @Test
+    public void testUnionFindSet() {
+        DisjointSetUnionBySize<Integer> dsu = new DisjointSetUnionBySize<>();
+        DisjointSetUnionBySize.Node<Integer> node1 = dsu.makeSet(1);
+        DisjointSetUnionBySize.Node<Integer> node2 = dsu.makeSet(2);
+        DisjointSetUnionBySize.Node<Integer> node3 = dsu.makeSet(3);
+        DisjointSetUnionBySize.Node<Integer> node4 = dsu.makeSet(4);
+
+        dsu.unionSets(node1, node2);
+        dsu.unionSets(node3, node2);
+        dsu.unionSets(node3, node4);
+        dsu.unionSets(node1, node3);
+
+        DisjointSetUnionBySize.Node<Integer> root1 = dsu.findSet(node1);
+        DisjointSetUnionBySize.Node<Integer> root2 = dsu.findSet(node2);
+        DisjointSetUnionBySize.Node<Integer> root3 = dsu.findSet(node3);
+        DisjointSetUnionBySize.Node<Integer> root4 = dsu.findSet(node4);
+
+        assertEquals(root1, root2);
+        assertEquals(root1, root3);
+        assertEquals(root1, root4);
+        assertEquals(4, root1.size);
+    }
+
+    @Test
+    public void testFindSetOnSingleNode() {
+        DisjointSetUnionBySize<String> dsu = new DisjointSetUnionBySize<>();
+        DisjointSetUnionBySize.Node<String> node = dsu.makeSet("A");
+        assertEquals(node, dsu.findSet(node));
+    }
+
+    @Test
+    public void testUnionAlreadyConnectedNodes() {
+        DisjointSetUnionBySize<Integer> dsu = new DisjointSetUnionBySize<>();
+        DisjointSetUnionBySize.Node<Integer> node1 = dsu.makeSet(1);
+        DisjointSetUnionBySize.Node<Integer> node2 = dsu.makeSet(2);
+        DisjointSetUnionBySize.Node<Integer> node3 = dsu.makeSet(3);
+
+        dsu.unionSets(node1, node2);
+        dsu.unionSets(node2, node3);
+
+        // Union nodes that are already connected
+        dsu.unionSets(node1, node3);
+
+        // All should have the same root
+        DisjointSetUnionBySize.Node<Integer> root = dsu.findSet(node1);
+        assertEquals(root, dsu.findSet(node2));
+        assertEquals(root, dsu.findSet(node3));
+        assertEquals(3, root.size);
+    }
+
+    @Test
+    public void testMultipleMakeSets() {
+        DisjointSetUnionBySize<Integer> dsu = new DisjointSetUnionBySize<>();
+        DisjointSetUnionBySize.Node<Integer> node1 = dsu.makeSet(1);
+        DisjointSetUnionBySize.Node<Integer> node2 = dsu.makeSet(2);
+        DisjointSetUnionBySize.Node<Integer> node3 = dsu.makeSet(3);
+
+        assertNotEquals(node1, node2);
+        assertNotEquals(node2, node3);
+        assertNotEquals(node1, node3);
+
+        assertEquals(node1, node1.parent);
+        assertEquals(node2, node2.parent);
+        assertEquals(node3, node3.parent);
+        assertEquals(1, node1.size);
+        assertEquals(1, node2.size);
+        assertEquals(1, node3.size);
+    }
+
+    @Test
+    public void testPathCompression() {
+        DisjointSetUnionBySize<Integer> dsu = new DisjointSetUnionBySize<>();
+        DisjointSetUnionBySize.Node<Integer> node1 = dsu.makeSet(1);
+        DisjointSetUnionBySize.Node<Integer> node2 = dsu.makeSet(2);
+        DisjointSetUnionBySize.Node<Integer> node3 = dsu.makeSet(3);
+
+        dsu.unionSets(node1, node2);
+        dsu.unionSets(node2, node3);
+
+        // After findSet, path compression should update parent to root directly
+        DisjointSetUnionBySize.Node<Integer> root = dsu.findSet(node3);
+        assertEquals(root, node1);
+        assertEquals(node1, node3.parent);
+        assertEquals(3, root.size);
+    }
+
+    @Test
+    public void testMultipleDisjointSets() {
+        DisjointSetUnionBySize<Integer> dsu = new DisjointSetUnionBySize<>();
+        DisjointSetUnionBySize.Node<Integer> node1 = dsu.makeSet(1);
+        DisjointSetUnionBySize.Node<Integer> node2 = dsu.makeSet(2);
+        DisjointSetUnionBySize.Node<Integer> node3 = dsu.makeSet(3);
+        DisjointSetUnionBySize.Node<Integer> node4 = dsu.makeSet(4);
+        DisjointSetUnionBySize.Node<Integer> node5 = dsu.makeSet(5);
+        DisjointSetUnionBySize.Node<Integer> node6 = dsu.makeSet(6);
+
+        // Create two separate components
+        dsu.unionSets(node1, node2);
+        dsu.unionSets(node2, node3);
+
+        dsu.unionSets(node4, node5);
+        dsu.unionSets(node5, node6);
+
+        // Verify they are separate
+        assertEquals(dsu.findSet(node1), dsu.findSet(node2));
+        assertEquals(dsu.findSet(node2), dsu.findSet(node3));
+        assertEquals(dsu.findSet(node4), dsu.findSet(node5));
+        assertEquals(dsu.findSet(node5), dsu.findSet(node6));
+
+        assertNotEquals(dsu.findSet(node1), dsu.findSet(node4));
+        assertNotEquals(dsu.findSet(node3), dsu.findSet(node6));
+    }
+
+    @Test
+    public void testEmptyValues() {
+        DisjointSetUnionBySize<String> dsu = new DisjointSetUnionBySize<>();
+        DisjointSetUnionBySize.Node<String> emptyNode = dsu.makeSet("");
+        DisjointSetUnionBySize.Node<String> nullNode = dsu.makeSet(null);
+
+        assertEquals(emptyNode, dsu.findSet(emptyNode));
+        assertEquals(nullNode, dsu.findSet(nullNode));
+
+        dsu.unionSets(emptyNode, nullNode);
+        assertEquals(dsu.findSet(emptyNode), dsu.findSet(nullNode));
+    }
+}

From 676d36eefd51da14742994265509d44fcee6adb4 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Thu, 4 Sep 2025 22:01:53 +0200
Subject: [PATCH 0943/1338] Update DIRECTORY.md (#6500)

Co-authored-by: DenizAltunkapan <DenizAltunkapan@users.noreply.github.com>
---
 DIRECTORY.md | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index c51396459476..549e166cc8a7 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -145,6 +145,7 @@
             - 📄 [TwoPSet](src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java)
           - 📁 **disjointsetunion**
             - 📄 [DisjointSetUnion](src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnion.java)
+            - 📄 [DisjointSetUnionBySize](src/main/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionBySize.java)
             - 📄 [Node](src/main/java/com/thealgorithms/datastructures/disjointsetunion/Node.java)
           - 📁 **dynamicarray**
             - 📄 [DynamicArray](src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java)
@@ -555,7 +556,6 @@
           - 📄 [PerlinNoise](src/main/java/com/thealgorithms/others/PerlinNoise.java)
           - 📄 [PrintAMatrixInSpiralOrder](src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java)
           - 📄 [QueueUsingTwoStacks](src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java)
-          - 📄 [ReverseStackUsingRecursion](src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
           - 📄 [SkylineProblem](src/main/java/com/thealgorithms/others/SkylineProblem.java)
           - 📄 [TwoPointers](src/main/java/com/thealgorithms/others/TwoPointers.java)
           - 📄 [Verhoeff](src/main/java/com/thealgorithms/others/Verhoeff.java)
@@ -740,7 +740,6 @@
           - 📄 [RemoveDuplicateFromString](src/main/java/com/thealgorithms/strings/RemoveDuplicateFromString.java)
           - 📄 [ReturnSubsequence](src/main/java/com/thealgorithms/strings/ReturnSubsequence.java)
           - 📄 [ReverseString](src/main/java/com/thealgorithms/strings/ReverseString.java)
-          - 📄 [ReverseStringRecursive](src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java)
           - 📄 [ReverseWordsInString](src/main/java/com/thealgorithms/strings/ReverseWordsInString.java)
           - 📄 [Rotation](src/main/java/com/thealgorithms/strings/Rotation.java)
           - 📄 [StringCompression](src/main/java/com/thealgorithms/strings/StringCompression.java)
@@ -886,6 +885,7 @@
             - 📄 [PNCounterTest](src/test/java/com/thealgorithms/datastructures/crdt/PNCounterTest.java)
             - 📄 [TwoPSetTest](src/test/java/com/thealgorithms/datastructures/crdt/TwoPSetTest.java)
           - 📁 **disjointsetunion**
+            - 📄 [DisjointSetUnionBySizeTest](src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionBySizeTest.java)
             - 📄 [DisjointSetUnionTest](src/test/java/com/thealgorithms/datastructures/disjointsetunion/DisjointSetUnionTest.java)
           - 📁 **dynamicarray**
             - 📄 [DynamicArrayTest](src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java)
@@ -1227,7 +1227,6 @@
           - 📄 [NextFitTest](src/test/java/com/thealgorithms/others/NextFitTest.java)
           - 📄 [PasswordGenTest](src/test/java/com/thealgorithms/others/PasswordGenTest.java)
           - 📄 [QueueUsingTwoStacksTest](src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java)
-          - 📄 [ReverseStackUsingRecursionTest](src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
           - 📄 [SkylineProblemTest](src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
           - 📄 [TestPrintMatrixInSpiralOrder](src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
           - 📄 [TwoPointersTest](src/test/java/com/thealgorithms/others/TwoPointersTest.java)
@@ -1409,7 +1408,6 @@
           - 📄 [PermuteStringTest](src/test/java/com/thealgorithms/strings/PermuteStringTest.java)
           - 📄 [RemoveDuplicateFromStringTest](src/test/java/com/thealgorithms/strings/RemoveDuplicateFromStringTest.java)
           - 📄 [ReturnSubsequenceTest](src/test/java/com/thealgorithms/strings/ReturnSubsequenceTest.java)
-          - 📄 [ReverseStringRecursiveTest](src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java)
           - 📄 [ReverseStringTest](src/test/java/com/thealgorithms/strings/ReverseStringTest.java)
           - 📄 [ReverseWordsInStringTest](src/test/java/com/thealgorithms/strings/ReverseWordsInStringTest.java)
           - 📄 [RotationTest](src/test/java/com/thealgorithms/strings/RotationTest.java)

From 5e5f31841d017698b52edc1aafac98b7cc91ed2b Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 5 Sep 2025 07:38:20 +0200
Subject: [PATCH 0944/1338] chore(deps): bump actions/stale from 9 to 10 in
 /.github/workflows (#6519)

Bumps [actions/stale](https://github.com/actions/stale) from 9 to 10.
- [Release notes](https://github.com/actions/stale/releases)
- [Changelog](https://github.com/actions/stale/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/stale/compare/v9...v10)

---
updated-dependencies:
- dependency-name: actions/stale
  dependency-version: '10'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/stale.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index 186b3e1d2f5a..bb613daf8f1d 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -11,7 +11,7 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/stale@v9
+      - uses: actions/stale@v10
         with:
           stale-issue-message: 'This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution!'
           close-issue-message: 'Please reopen this issue once you have made the required changes. If you need help, feel free to ask in our [Discord](https://the-algorithms.com/discord) server or ping one of the maintainers here. Thank you for your contribution!'

From f0437fecb84d92e8775fbe04789fa9cf8c6c13dc Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 5 Sep 2025 08:07:17 +0200
Subject: [PATCH 0945/1338] chore(deps): bump actions/setup-python from 5 to 6
 in /.github/workflows (#6520)

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 5 to 6.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/project_structure.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/project_structure.yml b/.github/workflows/project_structure.yml
index 369541b5fbf7..f9fb82a2781c 100644
--- a/.github/workflows/project_structure.yml
+++ b/.github/workflows/project_structure.yml
@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: '3.13'
 

From 6c8de5608776ac5f2c3be9fa1a09282057989382 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 9 Sep 2025 07:31:44 +0200
Subject: [PATCH 0946/1338] chore(deps): bump gitpod/workspace-java-21 from
 2025-06-18-16-47-14 to 2025-08-25-18-17-39 (#6523)

chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2025-06-18-16-47-14 to 2025-08-25-18-17-39.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-version: 2025-08-25-18-17-39
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index b912ecb35256..ef76c6fc68a6 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2025-06-18-16-47-14
+FROM gitpod/workspace-java-21:2025-08-25-18-17-39
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From f12e73489a6435acf40ccd37edea14842d0e5684 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 9 Sep 2025 08:31:35 +0200
Subject: [PATCH 0947/1338] chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.4.1 to 4.9.4.2 (#6524)

chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.4.1 to 4.9.4.2.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.4.1...spotbugs-maven-plugin-4.9.4.2)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.4.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index e9714fb3654e..72f6e3bcca5d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -120,7 +120,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.4.1</version>
+                <version>4.9.4.2</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 1472e5199269a9dae18091f32b6c15a91f56bd7c Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 16 Sep 2025 00:37:15 +0200
Subject: [PATCH 0948/1338] chore(deps): bump
 org.apache.maven.plugins:maven-surefire-plugin from 3.5.3 to 3.5.4 (#6527)

chore(deps): bump org.apache.maven.plugins:maven-surefire-plugin

Bumps [org.apache.maven.plugins:maven-surefire-plugin](https://github.com/apache/maven-surefire) from 3.5.3 to 3.5.4.
- [Release notes](https://github.com/apache/maven-surefire/releases)
- [Commits](https://github.com/apache/maven-surefire/compare/surefire-3.5.3...surefire-3.5.4)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-surefire-plugin
  dependency-version: 3.5.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 72f6e3bcca5d..a58b7fed059c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -61,7 +61,7 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.5.3</version>
+                <version>3.5.4</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>

From c3701011517ab1373e55d28f1cab869b8ffa98b1 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 15 Sep 2025 22:40:57 +0000
Subject: [PATCH 0949/1338] chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.4.2 to 4.9.5.0 (#6528)

chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.4.2 to 4.9.5.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.4.2...spotbugs-maven-plugin-4.9.5.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.5.0
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index a58b7fed059c..ea042d5af390 100644
--- a/pom.xml
+++ b/pom.xml
@@ -120,7 +120,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.4.2</version>
+                <version>4.9.5.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 85a2df46ad9afe244f1bc113afa737fd790ebbd8 Mon Sep 17 00:00:00 2001
From: Nithin U <106614289+NithinU2802@users.noreply.github.com>
Date: Wed, 17 Sep 2025 21:26:10 +0530
Subject: [PATCH 0950/1338] To add Suffix array algorithm implementation
 (#6530)

* adding Suffix Array Implementation

* adding test for Suffix Array

* patch: lint fix in SuffixArray.java

* patch: lint fix in SuffixArrayTest.java

* fix: private constructor update

* patch: lint fix in suffix array impl

* fix: lint issue line blankspace removal

* fix: checkstype issue

* fix: lint format issue

* Update DIRECTORY.md
---
 DIRECTORY.md                                  |  2 +
 .../thealgorithms/strings/SuffixArray.java    | 60 +++++++++++++++++++
 .../strings/SuffixArrayTest.java              | 44 ++++++++++++++
 3 files changed, 106 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/SuffixArray.java
 create mode 100644 src/test/java/com/thealgorithms/strings/SuffixArrayTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 549e166cc8a7..13d1fe39c168 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -744,6 +744,7 @@
           - 📄 [Rotation](src/main/java/com/thealgorithms/strings/Rotation.java)
           - 📄 [StringCompression](src/main/java/com/thealgorithms/strings/StringCompression.java)
           - 📄 [StringMatchFiniteAutomata](src/main/java/com/thealgorithms/strings/StringMatchFiniteAutomata.java)
+          - 📄 [SuffixArray](src/main/java/com/thealgorithms/strings/SuffixArray.java)
           - 📄 [Upper](src/main/java/com/thealgorithms/strings/Upper.java)
           - 📄 [ValidParentheses](src/main/java/com/thealgorithms/strings/ValidParentheses.java)
           - 📄 [WordLadder](src/main/java/com/thealgorithms/strings/WordLadder.java)
@@ -1413,6 +1414,7 @@
           - 📄 [RotationTest](src/test/java/com/thealgorithms/strings/RotationTest.java)
           - 📄 [StringCompressionTest](src/test/java/com/thealgorithms/strings/StringCompressionTest.java)
           - 📄 [StringMatchFiniteAutomataTest](src/test/java/com/thealgorithms/strings/StringMatchFiniteAutomataTest.java)
+          - 📄 [SuffixArrayTest](src/test/java/com/thealgorithms/strings/SuffixArrayTest.java)
           - 📄 [UpperTest](src/test/java/com/thealgorithms/strings/UpperTest.java)
           - 📄 [ValidParenthesesTest](src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java)
           - 📄 [WordLadderTest](src/test/java/com/thealgorithms/strings/WordLadderTest.java)
diff --git a/src/main/java/com/thealgorithms/strings/SuffixArray.java b/src/main/java/com/thealgorithms/strings/SuffixArray.java
new file mode 100644
index 000000000000..dbcac147b658
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/SuffixArray.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.strings;
+
+import java.util.Arrays;
+
+/**
+ * Suffix Array implementation in Java.
+ * Builds an array of indices that represent all suffixes of a string in sorted order.
+ * Wikipedia Reference: https://en.wikipedia.org/wiki/Suffix_array
+ * Author: Nithin U.
+ * Github: https://github.com/NithinU2802
+ */
+
+public final class SuffixArray {
+
+    private SuffixArray() {
+    }
+
+    public static int[] buildSuffixArray(String text) {
+        int n = text.length();
+        Integer[] suffixArray = new Integer[n];
+        int[] rank = new int[n];
+        int[] tempRank = new int[n];
+
+        // Initial ranking based on characters
+        for (int i = 0; i < n; i++) {
+            suffixArray[i] = i;
+            rank[i] = text.charAt(i);
+        }
+
+        for (int k = 1; k < n; k *= 2) {
+            final int step = k;
+
+            // Comparator: first by rank, then by rank + step
+            Arrays.sort(suffixArray, (a, b) -> {
+                if (rank[a] != rank[b]) {
+                    return Integer.compare(rank[a], rank[b]);
+                }
+                int ra = (a + step < n) ? rank[a + step] : -1;
+                int rb = (b + step < n) ? rank[b + step] : -1;
+                return Integer.compare(ra, rb);
+            });
+
+            // Re-rank
+            tempRank[suffixArray[0]] = 0;
+            for (int i = 1; i < n; i++) {
+                int prev = suffixArray[i - 1];
+                int curr = suffixArray[i];
+                boolean sameRank = rank[prev] == rank[curr] && ((prev + step < n ? rank[prev + step] : -1) == (curr + step < n ? rank[curr + step] : -1));
+                tempRank[curr] = sameRank ? tempRank[prev] : tempRank[prev] + 1;
+            }
+
+            System.arraycopy(tempRank, 0, rank, 0, n);
+
+            if (rank[suffixArray[n - 1]] == n - 1) {
+                break;
+            }
+        }
+        return Arrays.stream(suffixArray).mapToInt(Integer::intValue).toArray();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/SuffixArrayTest.java b/src/test/java/com/thealgorithms/strings/SuffixArrayTest.java
new file mode 100644
index 000000000000..9d4b3d582b75
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/SuffixArrayTest.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+class SuffixArrayTest {
+
+    @Test
+    void testEmptyString() {
+        int[] result = SuffixArray.buildSuffixArray("");
+        assertArrayEquals(new int[] {}, result, "Empty string should return empty suffix array");
+    }
+
+    @Test
+    void testSingleCharacter() {
+        int[] result = SuffixArray.buildSuffixArray("a");
+        assertArrayEquals(new int[] {0}, result, "Single char string should return [0]");
+    }
+
+    @Test
+    void testDistinctCharacters() {
+        int[] result = SuffixArray.buildSuffixArray("abc");
+        assertArrayEquals(new int[] {0, 1, 2}, result, "Suffixes already in order for distinct chars");
+    }
+
+    @Test
+    void testBananaExample() {
+        int[] result = SuffixArray.buildSuffixArray("banana");
+        assertArrayEquals(new int[] {5, 3, 1, 0, 4, 2}, result, "Suffix array of 'banana' should be [5,3,1,0,4,2]");
+    }
+
+    @Test
+    void testStringWithDuplicates() {
+        int[] result = SuffixArray.buildSuffixArray("aaaa");
+        assertArrayEquals(new int[] {3, 2, 1, 0}, result, "Suffix array should be descending indices for 'aaaa'");
+    }
+
+    @Test
+    void testRandomString() {
+        int[] result = SuffixArray.buildSuffixArray("mississippi");
+        assertArrayEquals(new int[] {10, 7, 4, 1, 0, 9, 8, 6, 3, 5, 2}, result, "Suffix array for 'mississippi' should match expected");
+    }
+}

From 45275ee935e33198dfbf63df63989fd4c4165e1d Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 18 Sep 2025 10:01:32 +0200
Subject: [PATCH 0951/1338] chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.5.0 to 4.9.6.0 (#6531)

chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.5.0 to 4.9.6.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.5.0...spotbugs-maven-plugin-4.9.6.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.6.0
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index ea042d5af390..14a0375fe170 100644
--- a/pom.xml
+++ b/pom.xml
@@ -120,7 +120,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.5.0</version>
+                <version>4.9.6.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 5fee204773acfe8d3a18dc92e421060821ecf81b Mon Sep 17 00:00:00 2001
From: Rahul P <rahul.cd23@bitsathy.ac.in>
Date: Thu, 18 Sep 2025 23:32:15 +0530
Subject: [PATCH 0952/1338] Added PriorityQueueSort algorithm and Tests (#6532)

* Added PriorityQueueSort.java

Implemented PriorityQueueSort using Java's PriorityQueue (Min-Heap).
- Returns the array sorted in ascending order
- Time complexity: O(n log n)
- Space complexity: O(n)

* Added tests for PriorityQueueSort

* Update PriorityQueueSortTest.java

* Fixed formatting and added full coverage tests for PriorityQueueSort

* Update PriorityQueueSort.java

* Update PriorityQueueSort.java

* Update PriorityQueueSort.java

* Update PriorityQueueSortTest.java

* Update PriorityQueueSort.java

* Update PriorityQueueSort.java

* Update PriorityQueueSort.java

* Fix formatting with clang-format
---
 .../sorts/PriorityQueueSort.java              | 49 ++++++++++++++++
 .../sorts/PriorityQueueSortTest.java          | 56 +++++++++++++++++++
 2 files changed, 105 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/PriorityQueueSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/PriorityQueueSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/PriorityQueueSort.java b/src/main/java/com/thealgorithms/sorts/PriorityQueueSort.java
new file mode 100644
index 000000000000..16f13050e8b3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/PriorityQueueSort.java
@@ -0,0 +1,49 @@
+package com.thealgorithms.sorts;
+
+import java.util.PriorityQueue;
+
+/**
+ * Sorts an array using Java's PriorityQueue (Min-Heap).
+ *
+ * <p>Example: Input: [7, 2, 9, 4, 1] Output: [1, 2, 4, 7, 9]
+ *
+ * <p>Time Complexity:
+ * - Inserting n elements into the PriorityQueue → O(n log n)
+ * - Polling n elements → O(n log n)
+ * - Total: O(n log n)
+ *
+ * <p>Space Complexity: O(n) for the PriorityQueue
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Heap_(data_structure)">
+ *     Heap / PriorityQueue</a>
+ */
+public final class PriorityQueueSort {
+
+    // Private constructor to prevent instantiation (utility class)
+    private PriorityQueueSort() {
+    }
+
+    /**
+     * Sorts the given array in ascending order using a PriorityQueue.
+     *
+     * @param arr the array to be sorted
+     * @return the sorted array (in-place)
+     */
+    public static int[] sort(int[] arr) {
+        if (arr == null || arr.length == 0) {
+            return arr;
+        }
+
+        PriorityQueue<Integer> pq = new PriorityQueue<>();
+        for (int num : arr) {
+            pq.offer(num);
+        }
+
+        int i = 0;
+        while (!pq.isEmpty()) {
+            arr[i++] = pq.poll();
+        }
+
+        return arr;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/PriorityQueueSortTest.java b/src/test/java/com/thealgorithms/sorts/PriorityQueueSortTest.java
new file mode 100644
index 000000000000..215431293227
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/PriorityQueueSortTest.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+class PriorityQueueSortTest {
+
+    @Test
+    void testNullArray() {
+        int[] input = null;
+        assertArrayEquals(null, PriorityQueueSort.sort(input));
+    }
+
+    @Test
+    void testSingleElementArray() {
+        int[] input = {5};
+        int[] expected = {5};
+        assertArrayEquals(expected, PriorityQueueSort.sort(input));
+    }
+
+    @Test
+    void testSortNormalArray() {
+        int[] input = {7, 2, 9, 4, 1};
+        int[] expected = {1, 2, 4, 7, 9};
+        assertArrayEquals(expected, PriorityQueueSort.sort(input));
+    }
+
+    @Test
+    void testEmptyArray() {
+        int[] input = {};
+        int[] expected = {};
+        assertArrayEquals(expected, PriorityQueueSort.sort(input));
+    }
+
+    @Test
+    void testNegativeNumbers() {
+        int[] input = {3, -1, 2, -5, 0};
+        int[] expected = {-5, -1, 0, 2, 3};
+        assertArrayEquals(expected, PriorityQueueSort.sort(input));
+    }
+
+    @Test
+    void testAlreadySortedArray() {
+        int[] input = {1, 2, 3, 4, 5};
+        int[] expected = {1, 2, 3, 4, 5};
+        assertArrayEquals(expected, PriorityQueueSort.sort(input));
+    }
+
+    @Test
+    void testArrayWithDuplicates() {
+        int[] input = {5, 1, 3, 3, 2, 5};
+        int[] expected = {1, 2, 3, 3, 5, 5};
+        assertArrayEquals(expected, PriorityQueueSort.sort(input));
+    }
+}

From f57ffa9e499ab9719d0965162261f9ee84afe66a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 19 Sep 2025 23:35:55 +0200
Subject: [PATCH 0953/1338] chore(deps-dev): bump org.assertj:assertj-core from
 3.27.4 to 3.27.5 (#6534)

Bumps [org.assertj:assertj-core](https://github.com/assertj/assertj) from 3.27.4 to 3.27.5.
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](https://github.com/assertj/assertj/compare/assertj-build-3.27.4...assertj-build-3.27.5)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-version: 3.27.5
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 14a0375fe170..da321e99377c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.27.4</assertj.version>
+        <assertj.version>3.27.5</assertj.version>
     </properties>
 
     <dependencyManagement>

From 0e74f01ab34a1e53bc84f4800088fc0bba67445b Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 22 Sep 2025 23:36:17 +0200
Subject: [PATCH 0954/1338] chore(deps-dev): bump org.assertj:assertj-core from
 3.27.5 to 3.27.6 (#6540)

Bumps [org.assertj:assertj-core](https://github.com/assertj/assertj) from 3.27.5 to 3.27.6.
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](https://github.com/assertj/assertj/compare/assertj-build-3.27.5...assertj-build-3.27.6)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-version: 3.27.6
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index da321e99377c..01752f8d010c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.27.5</assertj.version>
+        <assertj.version>3.27.6</assertj.version>
     </properties>
 
     <dependencyManagement>

From eb4304ec1705ba0faa5f1987d713054069b54be5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 22 Sep 2025 23:45:47 +0200
Subject: [PATCH 0955/1338] chore(deps): bump
 org.apache.maven.plugins:maven-compiler-plugin from 3.14.0 to 3.14.1 (#6539)

chore(deps): bump org.apache.maven.plugins:maven-compiler-plugin

Bumps [org.apache.maven.plugins:maven-compiler-plugin](https://github.com/apache/maven-compiler-plugin) from 3.14.0 to 3.14.1.
- [Release notes](https://github.com/apache/maven-compiler-plugin/releases)
- [Commits](https://github.com/apache/maven-compiler-plugin/compare/maven-compiler-plugin-3.14.0...maven-compiler-plugin-3.14.1)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-compiler-plugin
  dependency-version: 3.14.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 01752f8d010c..86b5ff4f7668 100644
--- a/pom.xml
+++ b/pom.xml
@@ -69,7 +69,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.14.0</version>
+                <version>3.14.1</version>
                 <configuration>
                     <source>21</source>
                     <target>21</target>

From ce314e11342054a716e5171db247e10c435d1e53 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 23 Sep 2025 13:56:03 +0300
Subject: [PATCH 0956/1338] chore(deps-dev): bump org.mockito:mockito-core from
 5.19.0 to 5.20.0 (#6541)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.19.0 to 5.20.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.19.0...v5.20.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.20.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 86b5ff4f7668..cb00c0f8d32e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.19.0</version>
+            <version>5.20.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From d29a8e523243fc791e5beb528e19011d4688fa3c Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
Date: Tue, 23 Sep 2025 13:20:05 +0200
Subject: [PATCH 0957/1338] Update DIRECTORY.md (#6533)

Co-authored-by: alxkm <alxkm@users.noreply.github.com>
Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 DIRECTORY.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 13d1fe39c168..8ae7aea61922 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -672,6 +672,7 @@
           - 📄 [PancakeSort](src/main/java/com/thealgorithms/sorts/PancakeSort.java)
           - 📄 [PatienceSort](src/main/java/com/thealgorithms/sorts/PatienceSort.java)
           - 📄 [PigeonholeSort](src/main/java/com/thealgorithms/sorts/PigeonholeSort.java)
+          - 📄 [PriorityQueueSort](src/main/java/com/thealgorithms/sorts/PriorityQueueSort.java)
           - 📄 [QuickSort](src/main/java/com/thealgorithms/sorts/QuickSort.java)
           - 📄 [RadixSort](src/main/java/com/thealgorithms/sorts/RadixSort.java)
           - 📄 [SelectionSort](src/main/java/com/thealgorithms/sorts/SelectionSort.java)
@@ -1345,6 +1346,7 @@
           - 📄 [PancakeSortTest](src/test/java/com/thealgorithms/sorts/PancakeSortTest.java)
           - 📄 [PatienceSortTest](src/test/java/com/thealgorithms/sorts/PatienceSortTest.java)
           - 📄 [PigeonholeSortTest](src/test/java/com/thealgorithms/sorts/PigeonholeSortTest.java)
+          - 📄 [PriorityQueueSortTest](src/test/java/com/thealgorithms/sorts/PriorityQueueSortTest.java)
           - 📄 [QuickSortTest](src/test/java/com/thealgorithms/sorts/QuickSortTest.java)
           - 📄 [RadixSortTest](src/test/java/com/thealgorithms/sorts/RadixSortTest.java)
           - 📄 [SelectionSortRecursiveTest](src/test/java/com/thealgorithms/sorts/SelectionSortRecursiveTest.java)

From 09cacae1c3ef570d2561dab0c0ac73e575081509 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 25 Sep 2025 08:05:55 +0200
Subject: [PATCH 0958/1338] chore(deps): bump org.apache.commons:commons-lang3
 from 3.18.0 to 3.19.0 (#6543)

Bumps org.apache.commons:commons-lang3 from 3.18.0 to 3.19.0.

---
updated-dependencies:
- dependency-name: org.apache.commons:commons-lang3
  dependency-version: 3.19.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index cb00c0f8d32e..9d46076f3f5c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -48,7 +48,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
-            <version>3.18.0</version>
+            <version>3.19.0</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>

From fb12971fd61982943d36ecc4bdae3b05eaa52e9f Mon Sep 17 00:00:00 2001
From: Hetu Kariya <hetukariya80@gmail.com>
Date: Sat, 27 Sep 2025 16:32:34 +0530
Subject: [PATCH 0959/1338] Added BitwiseGCD.java and BitwiseGCDTest.java
 (#6545)

---
 .../bitmanipulation/BitwiseGCD.java           | 147 ++++++++++++++++++
 .../bitmanipulation/BitwiseGCDTest.java       | 110 +++++++++++++
 2 files changed, 257 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/BitwiseGCD.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/BitwiseGCDTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/BitwiseGCD.java b/src/main/java/com/thealgorithms/bitmanipulation/BitwiseGCD.java
new file mode 100644
index 000000000000..516563459256
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/BitwiseGCD.java
@@ -0,0 +1,147 @@
+package com.thealgorithms.bitmanipulation;
+
+import java.math.BigInteger;
+
+/**
+ * Bitwise GCD implementation with full-range support utilities.
+ *
+ * <p>This class provides a fast binary (Stein's) GCD implementation for {@code long}
+ * inputs and a BigInteger-backed API for full 2's-complement range support (including
+ * {@code Long.MIN_VALUE}). The {@code long} implementation is efficient and avoids
+ * division/modulo operations. For edge-cases that overflow signed-64-bit ranges
+ * (e.g., gcd(Long.MIN_VALUE, 0) = 2^63), use the BigInteger API {@code gcdBig}.
+ *
+ * <p>Behaviour:
+ * <ul>
+ *   <li>{@code gcd(long,long)} : returns non-negative {@code long} gcd for inputs whose
+ *       absolute values fit in signed {@code long} (i.e., not causing an unsigned 2^63 result).
+ *       If the true gcd does not fit in a signed {@code long} (for example gcd(Long.MIN_VALUE,0) = 2^63)
+ *       this method will delegate to BigInteger and throw {@link ArithmeticException} if the
+ *       BigInteger result does not fit into a signed {@code long}.</li>
+ *   <li>{@code gcdBig(BigInteger, BigInteger)} : returns the exact gcd as a {@link BigInteger}
+ *       and works for the full signed-64-bit range and beyond.</li>
+ * </ul>
+ */
+public final class BitwiseGCD {
+
+    private BitwiseGCD() {
+    }
+
+    /**
+     * Computes GCD of two long values using Stein's algorithm (binary GCD).
+     * <p>Handles negative inputs. If either input is {@code Long.MIN_VALUE} the
+     * method delegates to the BigInteger implementation and will throw {@link ArithmeticException}
+     * if the result cannot be represented as a signed {@code long}.
+     *
+     * @param a first value (may be negative)
+     * @param b second value (may be negative)
+     * @return non-negative gcd as a {@code long}
+     * @throws ArithmeticException when the exact gcd does not fit into a signed {@code long}
+     */
+    public static long gcd(long a, long b) {
+        // Trivial cases
+        if (a == 0L) {
+            return absOrThrowIfOverflow(b);
+        }
+        if (b == 0L) {
+            return absOrThrowIfOverflow(a);
+        }
+
+        // If either is Long.MIN_VALUE, absolute value doesn't fit into signed long.
+        if (a == Long.MIN_VALUE || b == Long.MIN_VALUE) {
+            // Delegate to BigInteger and try to return a long if it fits
+            BigInteger g = gcdBig(BigInteger.valueOf(a), BigInteger.valueOf(b));
+            return g.longValueExact();
+        }
+
+        // Work with non-negative long values now (safe because we excluded Long.MIN_VALUE)
+        a = (a < 0) ? -a : a;
+        b = (b < 0) ? -b : b;
+
+        // Count common factors of 2
+        int commonTwos = Long.numberOfTrailingZeros(a | b);
+
+        // Remove all factors of 2 from a
+        a >>= Long.numberOfTrailingZeros(a);
+
+        while (b != 0L) {
+            // Remove all factors of 2 from b
+            b >>= Long.numberOfTrailingZeros(b);
+
+            // Now both a and b are odd. Ensure a <= b
+            if (a > b) {
+                long tmp = a;
+                a = b;
+                b = tmp;
+            }
+
+            // b >= a; subtract a from b (result is even)
+            b = b - a;
+        }
+
+        // Restore common powers of two
+        return a << commonTwos;
+    }
+
+    /**
+     * Helper to return absolute value of x unless x == Long.MIN_VALUE, in which
+     * case we delegate to BigInteger and throw to indicate overflow.
+     */
+    private static long absOrThrowIfOverflow(long x) {
+        if (x == Long.MIN_VALUE) {
+            // |Long.MIN_VALUE| = 2^63 which does not fit into signed long
+            throw new ArithmeticException("Absolute value of Long.MIN_VALUE does not fit into signed long. Use gcdBig() for full-range support.");
+        }
+        return (x < 0) ? -x : x;
+    }
+
+    /**
+     * Computes GCD for an array of {@code long} values. Returns 0 for empty/null arrays.
+     * If any intermediate gcd cannot be represented in signed long (rare), an ArithmeticException
+     * will be thrown.
+     */
+    public static long gcd(long... values) {
+
+        if (values == null || values.length == 0) {
+            return 0L;
+        }
+        long result = values[0];
+        for (int i = 1; i < values.length; i++) {
+            result = gcd(result, values[i]);
+            if (result == 1L) {
+                return 1L; // early exit
+            }
+        }
+        return result;
+    }
+
+    /**
+     * BigInteger-backed gcd that works for the full integer range (and beyond).
+     * This is the recommended method when inputs may be Long.MIN_VALUE or when you
+     * need an exact result even if it is greater than Long.MAX_VALUE.
+     * @param a first value (may be negative)
+     * @param b second value (may be negative)
+     * @return non-negative gcd as a {@link BigInteger}
+     */
+    public static BigInteger gcdBig(BigInteger a, BigInteger b) {
+
+        if (a == null || b == null) {
+            throw new NullPointerException("Arguments must not be null");
+        }
+        return a.abs().gcd(b.abs());
+    }
+
+    /**
+     * Convenience overload that accepts signed-64 inputs and returns BigInteger gcd.
+     */
+    public static BigInteger gcdBig(long a, long b) {
+        return gcdBig(BigInteger.valueOf(a), BigInteger.valueOf(b));
+    }
+
+    /**
+     * int overload for convenience.
+     */
+    public static int gcd(int a, int b) {
+        return (int) gcd((long) a, (long) b);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/BitwiseGCDTest.java b/src/test/java/com/thealgorithms/bitmanipulation/BitwiseGCDTest.java
new file mode 100644
index 000000000000..207fdc1e57a0
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/BitwiseGCDTest.java
@@ -0,0 +1,110 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.math.BigInteger;
+import org.junit.jupiter.api.Test;
+
+public class BitwiseGCDTest {
+
+    @Test
+    public void testGcdBasic() {
+        assertEquals(6L, BitwiseGCD.gcd(48L, 18L));
+    }
+
+    @Test
+    public void testGcdZeroAndNonZero() {
+        assertEquals(5L, BitwiseGCD.gcd(0L, 5L));
+        assertEquals(5L, BitwiseGCD.gcd(5L, 0L));
+    }
+
+    @Test
+    public void testGcdBothZero() {
+        assertEquals(0L, BitwiseGCD.gcd(0L, 0L));
+    }
+
+    @Test
+    public void testGcdNegativeInputs() {
+        assertEquals(6L, BitwiseGCD.gcd(-48L, 18L));
+        assertEquals(6L, BitwiseGCD.gcd(48L, -18L));
+        assertEquals(6L, BitwiseGCD.gcd(-48L, -18L));
+    }
+
+    @Test
+    public void testGcdIntOverload() {
+        assertEquals(6, BitwiseGCD.gcd(48, 18));
+    }
+
+    @Test
+    public void testGcdArray() {
+        long[] values = {48L, 18L, 6L};
+        assertEquals(6L, BitwiseGCD.gcd(values));
+    }
+
+    @Test
+    public void testGcdEmptyArray() {
+        long[] empty = {};
+        assertEquals(0L, BitwiseGCD.gcd(empty));
+    }
+
+    @Test
+    public void testGcdCoprime() {
+        assertEquals(1L, BitwiseGCD.gcd(17L, 13L));
+    }
+
+    @Test
+    public void testGcdPowersOfTwo() {
+        assertEquals(1024L, BitwiseGCD.gcd(1L << 20, 1L << 10));
+    }
+
+    @Test
+    public void testGcdLargeNumbers() {
+        assertEquals(6L, BitwiseGCD.gcd(270L, 192L));
+    }
+
+    @Test
+    public void testGcdEarlyExitArray() {
+        long[] manyCoprimes = {7L, 11L, 13L, 17L, 19L, 23L, 29L};
+        assertEquals(1L, BitwiseGCD.gcd(manyCoprimes));
+    }
+
+    @Test
+    public void testGcdSameNumbers() {
+        assertEquals(42L, BitwiseGCD.gcd(42L, 42L));
+    }
+
+    @Test
+    public void testGcdLongMinValueBigInteger() {
+        // gcd(Long.MIN_VALUE, 0) = |Long.MIN_VALUE| = 2^63; must use BigInteger to represent it
+        BigInteger expected = BigInteger.ONE.shiftLeft(63); // 2^63
+        assertEquals(expected, BitwiseGCD.gcdBig(Long.MIN_VALUE, 0L));
+    }
+
+    @Test
+    public void testGcdLongMinValueLongOverloadThrows() {
+        // The long overload cannot return 2^63 as a positive signed long, so it must throw
+        assertThrows(ArithmeticException.class, () -> BitwiseGCD.gcd(Long.MIN_VALUE, 0L));
+    }
+
+    @Test
+    public void testGcdWithLongMinAndOther() {
+        // gcd(Long.MIN_VALUE, 2^10) should be 2^10
+        long p = 1L << 10;
+        BigInteger expected = BigInteger.valueOf(p);
+        assertEquals(expected, BitwiseGCD.gcdBig(Long.MIN_VALUE, p));
+    }
+
+    @Test
+    public void testGcdWithBothLongMin() {
+        // gcd(Long.MIN_VALUE, Long.MIN_VALUE) = 2^63
+        BigInteger expected = BigInteger.ONE.shiftLeft(63);
+        assertEquals(expected, BitwiseGCD.gcdBig(Long.MIN_VALUE, Long.MIN_VALUE));
+    }
+
+    @Test
+    public void testGcdEdgeCasesMixed() {
+        assertEquals(1L, BitwiseGCD.gcd(1L, Long.MAX_VALUE));
+        assertEquals(1L, BitwiseGCD.gcd(Long.MAX_VALUE, 1L));
+    }
+}

From ef681e844de46e2b2ce57170c67ea6dc1f52c0be Mon Sep 17 00:00:00 2001
From: Milad Sadeghi <MiladSadeghiDM@Gmail.com>
Date: Mon, 29 Sep 2025 13:43:50 +0330
Subject: [PATCH 0960/1338] DEV: Implementing Alternative String Arrange
 (#6551)

---
 .../strings/AlternativeStringArrange.java     | 48 +++++++++++++++++++
 .../strings/AlternativeStringArrangeTest.java | 23 +++++++++
 2 files changed, 71 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/AlternativeStringArrange.java
 create mode 100644 src/test/java/com/thealgorithms/strings/AlternativeStringArrangeTest.java

diff --git a/src/main/java/com/thealgorithms/strings/AlternativeStringArrange.java b/src/main/java/com/thealgorithms/strings/AlternativeStringArrange.java
new file mode 100644
index 000000000000..cf736dbd8cab
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/AlternativeStringArrange.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.strings;
+
+/**
+ * This class provides a method to arrange two strings by alternating their characters.
+ * If one string is longer, the remaining characters of the longer string are appended at the end.
+ * <p>
+ * Example:
+ * Input: "abc", "12345"
+ * Output: "a1b2c345"
+ * <p>
+ * Input: "abcd", "12"
+ * Output: "a1b2cd"
+ *
+ * @author Milad Sadeghi
+ */
+public final class AlternativeStringArrange {
+
+    // Private constructor to prevent instantiation
+    private AlternativeStringArrange() {
+    }
+
+    /**
+     * Arranges two strings by alternating their characters.
+     *
+     * @param firstString  the first input string
+     * @param secondString the second input string
+     * @return a new string with characters from both strings arranged alternately
+     */
+    public static String arrange(String firstString, String secondString) {
+        StringBuilder result = new StringBuilder();
+        int length1 = firstString.length();
+        int length2 = secondString.length();
+        int minLength = Math.min(length1, length2);
+
+        for (int i = 0; i < minLength; i++) {
+            result.append(firstString.charAt(i));
+            result.append(secondString.charAt(i));
+        }
+
+        if (length1 > length2) {
+            result.append(firstString.substring(minLength));
+        } else if (length2 > length1) {
+            result.append(secondString.substring(minLength));
+        }
+
+        return result.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/AlternativeStringArrangeTest.java b/src/test/java/com/thealgorithms/strings/AlternativeStringArrangeTest.java
new file mode 100644
index 000000000000..9e8ae9e9f153
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/AlternativeStringArrangeTest.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class AlternativeStringArrangeTest {
+
+    // Method to provide test data
+    private static Stream<Object[]> provideTestData() {
+        return Stream.of(new Object[] {"abc", "12345", "a1b2c345"}, new Object[] {"abcd", "12", "a1b2cd"}, new Object[] {"", "123", "123"}, new Object[] {"abc", "", "abc"}, new Object[] {"a", "1", "a1"}, new Object[] {"ab", "12", "a1b2"}, new Object[] {"abcdef", "123", "a1b2c3def"},
+            new Object[] {"ab", "123456", "a1b23456"});
+    }
+
+    // Parameterized test using the provided test data
+    @ParameterizedTest(name = "{0} and {1} should return {2}")
+    @MethodSource("provideTestData")
+    void arrangeTest(String input1, String input2, String expected) {
+        assertEquals(expected, AlternativeStringArrange.arrange(input1, input2));
+    }
+}

From 881dafb37d28fa45c7f6e4d58a841a6ff03f3bc5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 30 Sep 2025 07:57:10 +0200
Subject: [PATCH 0961/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 11.0.0 to 11.1.0 (#6555)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 11.0.0 to 11.1.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-11.0.0...checkstyle-11.1.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 11.1.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 9d46076f3f5c..c69dec866788 100644
--- a/pom.xml
+++ b/pom.xml
@@ -113,7 +113,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>11.0.0</version>
+                    <version>11.1.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From f9a9ccb6b135d9ef6235af7c6b2e3c9ba7f9d096 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 30 Sep 2025 23:46:48 +0200
Subject: [PATCH 0962/1338] chore(deps): bump org.junit:junit-bom from 5.13.4
 to 6.0.0 (#6558)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 5.13.4 to 6.0.0.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r5.13.4...r6.0.0)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index c69dec866788..2122e6660da3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.13.4</version>
+                <version>6.0.0</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 421ac6d74fe05b3f81e1f62ea6be0e73e4db7db8 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 1 Oct 2025 09:06:50 +0200
Subject: [PATCH 0963/1338] style: include
 `RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE` (#6559)

---
 spotbugs-exclude.xml                                           | 3 ---
 .../java/com/thealgorithms/datastructures/caches/LFUCache.java | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 4f327a443781..d2e094556d61 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -80,9 +80,6 @@
     <Match>
         <Bug pattern="SA_FIELD_SELF_ASSIGNMENT" />
     </Match>
-    <Match>
-        <Bug pattern="RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE" />
-    </Match>
     <Match>
         <Bug pattern="AT_STALE_THREAD_WRITE_OF_PRIMITIVE" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java b/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
index f0d8ea8f7ff3..bf2b928ec33c 100644
--- a/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
+++ b/src/main/java/com/thealgorithms/datastructures/caches/LFUCache.java
@@ -132,7 +132,7 @@ public void put(K key, V value) {
     private void addNodeWithUpdatedFrequency(Node node) {
         if (tail != null && head != null) {
             Node temp = this.head;
-            while (temp != null) {
+            while (true) {
                 if (temp.frequency > node.frequency) {
                     if (temp == head) {
                         node.next = temp;

From 5e9d9f73372e57e17873c1353f7b2fe984ad675e Mon Sep 17 00:00:00 2001
From: Richa Kiran <64418209+richk21@users.noreply.github.com>
Date: Wed, 1 Oct 2025 18:29:15 +0530
Subject: [PATCH 0964/1338] Added Circular Doubly Linked List in the
 datastructures section (#6565)

---
 .../lists/CircularDoublyLinkedList.java       | 118 +++++++++++++++++
 .../lists/CircularDoublyLinkedListTest.java   | 120 ++++++++++++++++++
 2 files changed, 238 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/lists/CircularDoublyLinkedList.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/CircularDoublyLinkedListTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/CircularDoublyLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/CircularDoublyLinkedList.java
new file mode 100644
index 000000000000..fbb48854c449
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/lists/CircularDoublyLinkedList.java
@@ -0,0 +1,118 @@
+package com.thealgorithms.datastructures.lists;
+
+/**
+ * This class is a circular doubly linked list implementation. In a circular
+ * doubly linked list,
+ * the last node points back to the first node and the first node points back to
+ * the last node,
+ * creating a circular chain in both directions.
+ *
+ * This implementation includes basic operations such as appending elements to
+ * the end,
+ * removing elements from a specified position, and converting the list to a
+ * string representation.
+ *
+ * @param <E> the type of elements held in this list
+ */
+public class CircularDoublyLinkedList<E> {
+    static final class Node<E> {
+        Node<E> next;
+        Node<E> prev;
+        E value;
+
+        private Node(E value, Node<E> next, Node<E> prev) {
+            this.value = value;
+            this.next = next;
+            this.prev = prev;
+        }
+    }
+
+    private int size;
+    Node<E> head = null;
+
+    /**
+     * Initializes a new circular doubly linked list. A dummy head node is used for
+     * simplicity,
+     * pointing initially to itself to ensure the list is never empty.
+     */
+    public CircularDoublyLinkedList() {
+        head = new Node<>(null, null, null);
+        head.next = head;
+        head.prev = head;
+        size = 0;
+    }
+
+    /**
+     * Returns the current size of the list.
+     *
+     * @return the number of elements in the list
+     */
+    public int getSize() {
+        return size;
+    }
+
+    /**
+     * Appends a new element to the end of the list. Throws a NullPointerException
+     * if
+     * a null value is provided.
+     *
+     * @param value the value to append to the list
+     * @throws NullPointerException if the value is null
+     */
+    public void append(E value) {
+        if (value == null) {
+            throw new NullPointerException("Cannot add null element to the list");
+        }
+        Node<E> newNode = new Node<>(value, head, head.prev);
+        head.prev.next = newNode;
+        head.prev = newNode;
+        size++;
+    }
+
+    /**
+     * Returns a string representation of the list in the format "[ element1,
+     * element2, ... ]".
+     * An empty list is represented as "[]".
+     *
+     * @return the string representation of the list
+     */
+    public String toString() {
+        if (size == 0) {
+            return "[]";
+        }
+        StringBuilder sb = new StringBuilder("[ ");
+        Node<E> current = head.next;
+        while (current != head) {
+            sb.append(current.value);
+            if (current.next != head) {
+                sb.append(", ");
+            }
+            current = current.next;
+        }
+        sb.append(" ]");
+        return sb.toString();
+    }
+
+    /**
+     * Removes and returns the element at the specified position in the list.
+     * Throws an IndexOutOfBoundsException if the position is invalid.
+     *
+     * @param pos the position of the element to remove
+     * @return the value of the removed element - pop operation
+     * @throws IndexOutOfBoundsException if the position is out of range
+     */
+    public E remove(int pos) {
+        if (pos >= size || pos < 0) {
+            throw new IndexOutOfBoundsException("Position out of bounds");
+        }
+        Node<E> current = head.next;
+        for (int i = 0; i < pos; i++) {
+            current = current.next;
+        }
+        current.prev.next = current.next;
+        current.next.prev = current.prev;
+        E removedValue = current.value;
+        size--;
+        return removedValue;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/CircularDoublyLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/CircularDoublyLinkedListTest.java
new file mode 100644
index 000000000000..faa2765a3264
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/CircularDoublyLinkedListTest.java
@@ -0,0 +1,120 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class CircularDoublyLinkedListTest {
+
+    private CircularDoublyLinkedList<Integer> list;
+
+    @BeforeEach
+    public void setUp() {
+        list = new CircularDoublyLinkedList<>();
+    }
+
+    @Test
+    public void testInitialSize() {
+        assertEquals(0, list.getSize(), "Initial size should be 0.");
+    }
+
+    @Test
+    public void testAppendAndSize() {
+        list.append(10);
+        list.append(20);
+        list.append(30);
+
+        assertEquals(3, list.getSize(), "Size after appends should be 3.");
+        assertEquals("[ 10, 20, 30 ]", list.toString(), "List content should match appended values.");
+    }
+
+    @Test
+    public void testRemove() {
+        list.append(10);
+        list.append(20);
+        list.append(30);
+
+        int removed = list.remove(1);
+        assertEquals(20, removed, "Removed element at index 1 should be 20.");
+
+        assertEquals("[ 10, 30 ]", list.toString(), "List content should reflect removal.");
+        assertEquals(2, list.getSize(), "Size after removal should be 2.");
+
+        removed = list.remove(0);
+        assertEquals(10, removed, "Removed element at index 0 should be 10.");
+        assertEquals("[ 30 ]", list.toString(), "List content should reflect second removal.");
+        assertEquals(1, list.getSize(), "Size after second removal should be 1.");
+    }
+
+    @Test
+    public void testRemoveInvalidIndex() {
+        list.append(10);
+        list.append(20);
+
+        assertThrows(IndexOutOfBoundsException.class, () -> list.remove(2), "Removing at invalid index 2 should throw exception.");
+        assertThrows(IndexOutOfBoundsException.class, () -> list.remove(-1), "Removing at negative index should throw exception.");
+    }
+
+    @Test
+    public void testToStringEmpty() {
+        assertEquals("[]", list.toString(), "Empty list should display as [].");
+    }
+
+    @Test
+    public void testSingleElement() {
+        list.append(10);
+
+        assertEquals(1, list.getSize(), "Size after adding single element should be 1.");
+        assertEquals("[ 10 ]", list.toString(), "Single element list string should be formatted correctly.");
+        int removed = list.remove(0);
+        assertEquals(10, removed, "Removed element should be the one appended.");
+        assertEquals("[]", list.toString(), "List should be empty after removing last element.");
+        assertEquals(0, list.getSize(), "Size after removing last element should be 0.");
+    }
+
+    @Test
+    public void testNullAppend() {
+        assertThrows(NullPointerException.class, () -> list.append(null), "Appending null should throw NullPointerException.");
+    }
+
+    @Test
+    public void testRemoveLastPosition() {
+        list.append(10);
+        list.append(20);
+        list.append(30);
+        int removed = list.remove(list.getSize() - 1);
+        assertEquals(30, removed, "Last element removed should be 30.");
+        assertEquals(2, list.getSize(), "Size should decrease after removing last element.");
+    }
+
+    @Test
+    public void testRemoveFromEmptyThrows() {
+        assertThrows(IndexOutOfBoundsException.class, () -> list.remove(0), "Remove from empty list should throw.");
+    }
+
+    @Test
+    public void testRepeatedAppendAndRemove() {
+        for (int i = 0; i < 100; i++) {
+            list.append(i);
+        }
+        assertEquals(100, list.getSize());
+
+        for (int i = 99; i >= 0; i--) {
+            int removed = list.remove(i);
+            assertEquals(i, removed, "Removed element should match appended value.");
+        }
+        assertEquals(0, list.getSize(), "List should be empty after all removes.");
+    }
+
+    @Test
+    public void testToStringAfterMultipleRemoves() {
+        list.append(1);
+        list.append(2);
+        list.append(3);
+        list.remove(2);
+        list.remove(0);
+        assertEquals("[ 2 ]", list.toString(), "ToString should correctly represent remaining elements.");
+    }
+}

From 05ceb192c9ffb909815e9f77e8c2121960385b70 Mon Sep 17 00:00:00 2001
From: Kunwar Partap Singh <116331466+kunwarbhattal@users.noreply.github.com>
Date: Thu, 2 Oct 2025 01:05:05 +0530
Subject: [PATCH 0965/1338] Bit swap enhancement (#6577)

---
 src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java b/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java
index d8c207567ba6..634c9e7b3b44 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java
@@ -17,12 +17,15 @@ private BitSwap() {
      * @return The modified value with swapped bits
      * @throws IllegalArgumentException if either position is negative or ≥ 32
      */
+
     public static int bitSwap(int data, final int posA, final int posB) {
         if (posA < 0 || posA >= Integer.SIZE || posB < 0 || posB >= Integer.SIZE) {
             throw new IllegalArgumentException("Bit positions must be between 0 and 31");
         }
 
-        if (SingleBitOperations.getBit(data, posA) != SingleBitOperations.getBit(data, posB)) {
+        boolean bitA = ((data >> posA) & 1) != 0;
+        boolean bitB = ((data >> posB) & 1) != 0;
+        if (bitA != bitB) {
             data ^= (1 << posA) ^ (1 << posB);
         }
         return data;

From f8f315eaa89dd37a76ef1cbe9136561156bf6362 Mon Sep 17 00:00:00 2001
From: Sivasuthan Sukumar <153247727+Sivasuthan9@users.noreply.github.com>
Date: Thu, 2 Oct 2025 01:14:43 +0530
Subject: [PATCH 0966/1338] Extend Graph Algorithms: Added Two Popular
 Algorithms: BronKerbosch, EdmondsKarp (#6576)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Bron–Kerbosch algorithm added.

* test:Bron–Kerbosch algorithm added.

* lint checked.

* clang-format linting checked.

* lint checked in remote

Removed duplicate import statements for assertions.

* Remove unnecessary blank line in BronKerboschTest

* EdmondsKarp algorithm added.

* reformatted

---------

Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 .../com/thealgorithms/graph/BronKerbosch.java | 114 ++++++++++++++++++
 .../com/thealgorithms/graph/EdmondsKarp.java  | 107 ++++++++++++++++
 .../thealgorithms/graph/BronKerboschTest.java |  79 ++++++++++++
 .../thealgorithms/graph/EdmondsKarpTest.java  |  48 ++++++++
 4 files changed, 348 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/BronKerbosch.java
 create mode 100644 src/main/java/com/thealgorithms/graph/EdmondsKarp.java
 create mode 100644 src/test/java/com/thealgorithms/graph/BronKerboschTest.java
 create mode 100644 src/test/java/com/thealgorithms/graph/EdmondsKarpTest.java

diff --git a/src/main/java/com/thealgorithms/graph/BronKerbosch.java b/src/main/java/com/thealgorithms/graph/BronKerbosch.java
new file mode 100644
index 000000000000..0510d9bcf494
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/BronKerbosch.java
@@ -0,0 +1,114 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Implementation of the Bron–Kerbosch algorithm with pivoting for enumerating all maximal cliques
+ * in an undirected graph.
+ *
+ * <p>The input graph is represented as an adjacency list where {@code adjacency.get(u)} returns the
+ * set of vertices adjacent to {@code u}. The algorithm runs in time proportional to the number of
+ * maximal cliques produced and is widely used for clique enumeration problems.</p>
+ *
+ * @author <a href="https://en.wikipedia.org/wiki/Bron%E2%80%93Kerbosch_algorithm">Wikipedia: Bron–Kerbosch algorithm</a>
+ */
+public final class BronKerbosch {
+
+    private BronKerbosch() {
+    }
+
+    /**
+     * Finds all maximal cliques of the provided graph.
+     *
+     * @param adjacency adjacency list where {@code adjacency.size()} equals the number of vertices
+     * @return a list containing every maximal clique, each represented as a {@link Set} of vertices
+     * @throws IllegalArgumentException if the adjacency list is {@code null}, contains {@code null}
+     *         entries, or references invalid vertices
+     */
+    public static List<Set<Integer>> findMaximalCliques(List<Set<Integer>> adjacency) {
+        if (adjacency == null) {
+            throw new IllegalArgumentException("Adjacency list must not be null");
+        }
+
+        int n = adjacency.size();
+        List<Set<Integer>> graph = new ArrayList<>(n);
+        for (int u = 0; u < n; u++) {
+            Set<Integer> neighbors = adjacency.get(u);
+            if (neighbors == null) {
+                throw new IllegalArgumentException("Adjacency list must not contain null sets");
+            }
+            Set<Integer> copy = new HashSet<>();
+            for (int v : neighbors) {
+                if (v < 0 || v >= n) {
+                    throw new IllegalArgumentException("Neighbor index out of bounds: " + v);
+                }
+                if (v != u) {
+                    copy.add(v);
+                }
+            }
+            graph.add(copy);
+        }
+
+        Set<Integer> r = new HashSet<>();
+        Set<Integer> p = new HashSet<>();
+        Set<Integer> x = new HashSet<>();
+        for (int v = 0; v < n; v++) {
+            p.add(v);
+        }
+
+        List<Set<Integer>> cliques = new ArrayList<>();
+        bronKerboschPivot(r, p, x, graph, cliques);
+        return cliques;
+    }
+
+    private static void bronKerboschPivot(Set<Integer> r, Set<Integer> p, Set<Integer> x, List<Set<Integer>> graph, List<Set<Integer>> cliques) {
+        if (p.isEmpty() && x.isEmpty()) {
+            cliques.add(new HashSet<>(r));
+            return;
+        }
+
+        int pivot = choosePivot(p, x, graph);
+        Set<Integer> candidates = new HashSet<>(p);
+        if (pivot != -1) {
+            candidates.removeAll(graph.get(pivot));
+        }
+
+        for (Integer v : candidates) {
+            r.add(v);
+            Set<Integer> newP = intersection(p, graph.get(v));
+            Set<Integer> newX = intersection(x, graph.get(v));
+            bronKerboschPivot(r, newP, newX, graph, cliques);
+            r.remove(v);
+            p.remove(v);
+            x.add(v);
+        }
+    }
+
+    private static int choosePivot(Set<Integer> p, Set<Integer> x, List<Set<Integer>> graph) {
+        int pivot = -1;
+        int maxDegree = -1;
+        Set<Integer> union = new HashSet<>(p);
+        union.addAll(x);
+        for (Integer v : union) {
+            int degree = graph.get(v).size();
+            if (degree > maxDegree) {
+                maxDegree = degree;
+                pivot = v;
+            }
+        }
+        return pivot;
+    }
+
+    private static Set<Integer> intersection(Set<Integer> base, Set<Integer> neighbors) {
+        Set<Integer> result = new HashSet<>();
+        for (Integer v : base) {
+            if (neighbors.contains(v)) {
+                result.add(v);
+            }
+        }
+        return result;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/graph/EdmondsKarp.java b/src/main/java/com/thealgorithms/graph/EdmondsKarp.java
new file mode 100644
index 000000000000..59e7b09cb49c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/EdmondsKarp.java
@@ -0,0 +1,107 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.Queue;
+
+/**
+ * Implementation of the Edmonds–Karp algorithm for computing the maximum flow of a directed graph.
+ * <p>
+ * The algorithm runs in O(V * E^2) time and is a specific implementation of the Ford–Fulkerson
+ * method where the augmenting paths are found using breadth-first search (BFS) to ensure the
+ * shortest augmenting paths (in terms of the number of edges) are used.
+ * </p>
+ *
+ * <p>The graph is represented with a capacity matrix where {@code capacity[u][v]} denotes the
+ * capacity of the edge from {@code u} to {@code v}. Negative capacities are not allowed.</p>
+ *
+ * @author <a href="https://en.wikipedia.org/wiki/Edmonds%E2%80%93Karp_algorithm">Wikipedia: EdmondsKarp algorithm</a>
+ */
+public final class EdmondsKarp {
+
+    private EdmondsKarp() {
+    }
+
+    /**
+     * Computes the maximum flow from {@code source} to {@code sink} in the provided capacity matrix.
+     *
+     * @param capacity the capacity matrix representing the directed graph; must be square and non-null
+     * @param source the source vertex index
+     * @param sink the sink vertex index
+     * @return the value of the maximum flow between {@code source} and {@code sink}
+     * @throws IllegalArgumentException if the matrix is {@code null}, not square, contains negative
+     *         capacities, or if {@code source} / {@code sink} indices are invalid
+     */
+    public static int maxFlow(int[][] capacity, int source, int sink) {
+        if (capacity == null || capacity.length == 0) {
+            throw new IllegalArgumentException("Capacity matrix must not be null or empty");
+        }
+
+        final int n = capacity.length;
+        for (int row = 0; row < n; row++) {
+            if (capacity[row] == null || capacity[row].length != n) {
+                throw new IllegalArgumentException("Capacity matrix must be square");
+            }
+            for (int col = 0; col < n; col++) {
+                if (capacity[row][col] < 0) {
+                    throw new IllegalArgumentException("Capacities must be non-negative");
+                }
+            }
+        }
+
+        if (source < 0 || source >= n || sink < 0 || sink >= n) {
+            throw new IllegalArgumentException("Source and sink must be valid vertex indices");
+        }
+        if (source == sink) {
+            return 0;
+        }
+
+        final int[][] residual = new int[n][n];
+        for (int i = 0; i < n; i++) {
+            residual[i] = Arrays.copyOf(capacity[i], n);
+        }
+
+        final int[] parent = new int[n];
+        int maxFlow = 0;
+
+        while (bfs(residual, source, sink, parent)) {
+            int pathFlow = Integer.MAX_VALUE;
+            for (int v = sink; v != source; v = parent[v]) {
+                int u = parent[v];
+                pathFlow = Math.min(pathFlow, residual[u][v]);
+            }
+
+            for (int v = sink; v != source; v = parent[v]) {
+                int u = parent[v];
+                residual[u][v] -= pathFlow;
+                residual[v][u] += pathFlow;
+            }
+
+            maxFlow += pathFlow;
+        }
+
+        return maxFlow;
+    }
+
+    private static boolean bfs(int[][] residual, int source, int sink, int[] parent) {
+        Arrays.fill(parent, -1);
+        parent[source] = source;
+
+        Queue<Integer> queue = new ArrayDeque<>();
+        queue.add(source);
+
+        while (!queue.isEmpty()) {
+            int u = queue.poll();
+            for (int v = 0; v < residual.length; v++) {
+                if (residual[u][v] > 0 && parent[v] == -1) {
+                    parent[v] = u;
+                    if (v == sink) {
+                        return true;
+                    }
+                    queue.add(v);
+                }
+            }
+        }
+        return false;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/BronKerboschTest.java b/src/test/java/com/thealgorithms/graph/BronKerboschTest.java
new file mode 100644
index 000000000000..54c91c6ac1fd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/BronKerboschTest.java
@@ -0,0 +1,79 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class BronKerboschTest {
+
+    @Test
+    @DisplayName("Complete graph returns single clique")
+    void completeGraph() {
+        List<Set<Integer>> adjacency = buildGraph(4);
+        addUndirectedEdge(adjacency, 0, 1);
+        addUndirectedEdge(adjacency, 0, 2);
+        addUndirectedEdge(adjacency, 0, 3);
+        addUndirectedEdge(adjacency, 1, 2);
+        addUndirectedEdge(adjacency, 1, 3);
+        addUndirectedEdge(adjacency, 2, 3);
+
+        List<Set<Integer>> cliques = BronKerbosch.findMaximalCliques(adjacency);
+        assertEquals(1, cliques.size());
+        assertEquals(Set.of(0, 1, 2, 3), cliques.get(0));
+    }
+
+    @Test
+    @DisplayName("Path graph produces individual edges")
+    void pathGraph() {
+        List<Set<Integer>> adjacency = buildGraph(3);
+        addUndirectedEdge(adjacency, 0, 1);
+        addUndirectedEdge(adjacency, 1, 2);
+
+        List<Set<Integer>> cliques = BronKerbosch.findMaximalCliques(adjacency);
+        Set<Set<Integer>> result = new HashSet<>(cliques);
+        Set<Set<Integer>> expected = Set.of(Set.of(0, 1), Set.of(1, 2));
+        assertEquals(expected, result);
+    }
+
+    @Test
+    @DisplayName("Disconnected graph finds cliques per component")
+    void disconnectedGraph() {
+        List<Set<Integer>> adjacency = buildGraph(5);
+        addUndirectedEdge(adjacency, 0, 1);
+        addUndirectedEdge(adjacency, 0, 2);
+        addUndirectedEdge(adjacency, 1, 2);
+        addUndirectedEdge(adjacency, 3, 4);
+
+        List<Set<Integer>> cliques = BronKerbosch.findMaximalCliques(adjacency);
+        Set<Set<Integer>> result = new HashSet<>(cliques);
+        Set<Set<Integer>> expected = Set.of(Set.of(0, 1, 2), Set.of(3, 4));
+        assertEquals(expected, result);
+    }
+
+    @Test
+    @DisplayName("Null neighbor set triggers exception")
+    void nullNeighborSet() {
+        List<Set<Integer>> adjacency = new ArrayList<>();
+        adjacency.add(null);
+        assertThrows(IllegalArgumentException.class, () -> BronKerbosch.findMaximalCliques(adjacency));
+    }
+
+    private static List<Set<Integer>> buildGraph(int n) {
+        List<Set<Integer>> graph = new ArrayList<>(n);
+        for (int i = 0; i < n; i++) {
+            graph.add(new HashSet<>());
+        }
+        return graph;
+    }
+
+    private static void addUndirectedEdge(List<Set<Integer>> graph, int u, int v) {
+        graph.get(u).add(v);
+        graph.get(v).add(u);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/EdmondsKarpTest.java b/src/test/java/com/thealgorithms/graph/EdmondsKarpTest.java
new file mode 100644
index 000000000000..55aeda381031
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/EdmondsKarpTest.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class EdmondsKarpTest {
+
+    @Test
+    @DisplayName("Classic CLRS network yields max flow 23")
+    void clrsExample() {
+        int[][] capacity = {{0, 16, 13, 0, 0, 0}, {0, 0, 10, 12, 0, 0}, {0, 4, 0, 0, 14, 0}, {0, 0, 9, 0, 0, 20}, {0, 0, 0, 7, 0, 4}, {0, 0, 0, 0, 0, 0}};
+        int maxFlow = EdmondsKarp.maxFlow(capacity, 0, 5);
+        assertEquals(23, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Disconnected network has zero flow")
+    void disconnectedGraph() {
+        int[][] capacity = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};
+        int maxFlow = EdmondsKarp.maxFlow(capacity, 0, 2);
+        assertEquals(0, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Source equals sink returns zero")
+    void sourceEqualsSink() {
+        int[][] capacity = {{0, 5}, {0, 0}};
+        int maxFlow = EdmondsKarp.maxFlow(capacity, 0, 0);
+        assertEquals(0, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Invalid matrix throws exception")
+    void invalidMatrix() {
+        int[][] capacity = {{0, 1}, {1}};
+        assertThrows(IllegalArgumentException.class, () -> EdmondsKarp.maxFlow(capacity, 0, 1));
+    }
+
+    @Test
+    @DisplayName("Negative capacity is rejected")
+    void negativeCapacity() {
+        int[][] capacity = {{0, -1}, {0, 0}};
+        assertThrows(IllegalArgumentException.class, () -> EdmondsKarp.maxFlow(capacity, 0, 1));
+    }
+}

From 15695c6e549c1cfb7af8e895de3f566d20f92ca6 Mon Sep 17 00:00:00 2001
From: Sourav Saha <72702534+yashsaha555@users.noreply.github.com>
Date: Thu, 2 Oct 2025 12:54:25 +0530
Subject: [PATCH 0967/1338] Fix MiniMaxAlgorithm setScores bug and add
 comprehensive tests (#6566)

* Fix MiniMaxAlgorithm setScores bug and add comprehensive tests

- Fix bug in setScores method where scores.length % 1 == 0 always returned true
- Add isPowerOfTwo helper method to properly validate array length
- Add comprehensive unit tests covering edge cases and algorithm correctness
- Tests include validation for power of 2 check, minimax logic, and error handling

Fixes issue with incorrect validation logic in MiniMaxAlgorithm.setScores()

* Fix Checkstyle violations and improve setScores validation

- Replace star imports with explicit imports in test file
- Remove trailing whitespaces from all lines
- Add proper file ending newline
- Improve setScores method to handle edge cases properly
- Use direct bit manipulation for power-of-2 check as suggested
- Ensure error message is printed and scores remain unchanged for invalid input

All Checkstyle violations resolved and tests pass successfully.

* Add missing newline at end of MiniMaxAlgorithmTest.java

- Fix Checkstyle violation: NewlineAtEndOfFile
- Ensure file ends with proper newline character
- All tests continue to pass successfully

* Fix PMD violation by utilizing isPowerOfTwo method

- Replace inline bit manipulation with isPowerOfTwo method call
- Resolves PMD UnusedPrivateMethod violation
- Maintains same validation logic and error handling
- All tests continue to pass successfully

* test: improve MiniMaxAlgorithm test coverage for CodeCov

- Add comprehensive test cases for isPowerOfTwo function edge cases
- Test setScores method with various invalid array lengths (0, 3, 5, 6, 7, 9, 10, 15)
- Add tests for large valid powers of 2 (up to 64 elements)
- Ensure complete coverage of error handling branches
- Increase test count from 14 to 19 tests
- Fix partial coverage issues identified in CodeCov report

Resolves CodeCov coverage gaps in MiniMaxAlgorithm.java

* Fix checkstyle errors

* Fix checkstyle errors

---------

Co-authored-by: ssaha <ssaha@wiley.com>
Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../others/MiniMaxAlgorithm.java              |  13 +-
 .../others/MiniMaxAlgorithmTest.java          | 277 ++++++++++++++++++
 2 files changed, 286 insertions(+), 4 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/MiniMaxAlgorithmTest.java

diff --git a/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java b/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java
index cd2cd02ab908..e0b96570a4fe 100644
--- a/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java
@@ -109,13 +109,18 @@ private int log2(int n) {
         return (n == 1) ? 0 : log2(n / 2) + 1;
     }
 
+    // A utility function to check if a number is a power of 2
+    private boolean isPowerOfTwo(int n) {
+        return n > 0 && (n & (n - 1)) == 0;
+    }
+
     public void setScores(int[] scores) {
-        if (scores.length % 1 == 0) {
-            this.scores = scores;
-            height = log2(this.scores.length);
-        } else {
+        if (!isPowerOfTwo(scores.length)) {
             System.out.println("The number of scores must be a power of 2.");
+            return;
         }
+        this.scores = scores;
+        height = log2(this.scores.length);
     }
 
     public int[] getScores() {
diff --git a/src/test/java/com/thealgorithms/others/MiniMaxAlgorithmTest.java b/src/test/java/com/thealgorithms/others/MiniMaxAlgorithmTest.java
new file mode 100644
index 000000000000..821eb3f16029
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/MiniMaxAlgorithmTest.java
@@ -0,0 +1,277 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for MiniMaxAlgorithm
+ * Tests the minimax algorithm implementation for game tree evaluation
+ */
+class MiniMaxAlgorithmTest {
+
+    private MiniMaxAlgorithm miniMax;
+    private final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+    private final PrintStream originalOut = System.out;
+
+    @BeforeEach
+    void setUp() {
+        miniMax = new MiniMaxAlgorithm();
+        System.setOut(new PrintStream(outputStream));
+    }
+
+    @Test
+    void testConstructorCreatesValidScores() {
+        // The default constructor should create scores array of length 8 (2^3)
+        assertEquals(8, miniMax.getScores().length);
+        assertEquals(3, miniMax.getHeight());
+
+        // All scores should be positive (between 1 and 99)
+        for (int score : miniMax.getScores()) {
+            assertTrue(score >= 1 && score <= 99);
+        }
+    }
+
+    @Test
+    void testSetScoresWithValidPowerOfTwo() {
+        int[] validScores = {10, 20, 30, 40};
+        miniMax.setScores(validScores);
+
+        assertArrayEquals(validScores, miniMax.getScores());
+        assertEquals(2, miniMax.getHeight()); // log2(4) = 2
+    }
+
+    @Test
+    void testSetScoresWithInvalidLength() {
+        int[] invalidScores = {10, 20, 30}; // Length 3 is not a power of 2
+        miniMax.setScores(invalidScores);
+
+        // Should print error message and not change the scores
+        String output = outputStream.toString();
+        assertTrue(output.contains("The number of scores must be a power of 2."));
+
+        // Scores should remain unchanged (original length 8)
+        assertEquals(8, miniMax.getScores().length);
+    }
+
+    @Test
+    void testSetScoresWithZeroLength() {
+        int[] emptyScores = {}; // Length 0 is not a power of 2
+        miniMax.setScores(emptyScores);
+
+        // Should print error message and not change the scores
+        String output = outputStream.toString();
+        assertTrue(output.contains("The number of scores must be a power of 2."));
+
+        // Scores should remain unchanged (original length 8)
+        assertEquals(8, miniMax.getScores().length);
+    }
+
+    @Test
+    void testSetScoresWithVariousInvalidLengths() {
+        // Test multiple invalid lengths to ensure isPowerOfTwo function is fully covered
+        int[][] invalidScoreArrays = {
+            {1, 2, 3, 4, 5}, // Length 5
+            {1, 2, 3, 4, 5, 6}, // Length 6
+            {1, 2, 3, 4, 5, 6, 7}, // Length 7
+            new int[9], // Length 9
+            new int[10], // Length 10
+            new int[15] // Length 15
+        };
+
+        for (int[] invalidScores : invalidScoreArrays) {
+            // Clear the output stream for each test
+            outputStream.reset();
+            miniMax.setScores(invalidScores);
+
+            // Should print error message for each invalid length
+            String output = outputStream.toString();
+            assertTrue(output.contains("The number of scores must be a power of 2."), "Failed for array length: " + invalidScores.length);
+        }
+
+        // Scores should remain unchanged (original length 8)
+        assertEquals(8, miniMax.getScores().length);
+    }
+
+    @Test
+    void testSetScoresWithSingleElement() {
+        int[] singleScore = {42};
+        miniMax.setScores(singleScore);
+
+        assertArrayEquals(singleScore, miniMax.getScores());
+        assertEquals(0, miniMax.getHeight()); // log2(1) = 0
+    }
+
+    @Test
+    void testMiniMaxWithKnownScores() {
+        // Test with a known game tree: [3, 12, 8, 2]
+        int[] testScores = {3, 12, 8, 2};
+        miniMax.setScores(testScores);
+
+        // Maximizer starts: should choose max(min(3,12), min(8,2)) = max(3, 2) = 3
+        int result = miniMax.miniMax(0, true, 0, false);
+        assertEquals(3, result);
+    }
+
+    @Test
+    void testMiniMaxWithMinimizerFirst() {
+        // Test with minimizer starting first
+        int[] testScores = {3, 12, 8, 2};
+        miniMax.setScores(testScores);
+
+        // Minimizer starts: should choose min(max(3,12), max(8,2)) = min(12, 8) = 8
+        int result = miniMax.miniMax(0, false, 0, false);
+        assertEquals(8, result);
+    }
+
+    @Test
+    void testMiniMaxWithLargerTree() {
+        // Test with 8 elements: [5, 6, 7, 4, 5, 3, 6, 2]
+        int[] testScores = {5, 6, 7, 4, 5, 3, 6, 2};
+        miniMax.setScores(testScores);
+
+        // Maximizer starts
+        int result = miniMax.miniMax(0, true, 0, false);
+        // Expected: max(min(max(5,6), max(7,4)), min(max(5,3), max(6,2)))
+        //         = max(min(6, 7), min(5, 6)) = max(6, 5) = 6
+        assertEquals(6, result);
+    }
+
+    @Test
+    void testMiniMaxVerboseOutput() {
+        int[] testScores = {3, 12, 8, 2};
+        miniMax.setScores(testScores);
+
+        miniMax.miniMax(0, true, 0, true);
+
+        String output = outputStream.toString();
+        assertTrue(output.contains("Maximizer"));
+        assertTrue(output.contains("Minimizer"));
+        assertTrue(output.contains("chooses"));
+    }
+
+    @Test
+    void testGetRandomScoresLength() {
+        int[] randomScores = MiniMaxAlgorithm.getRandomScores(4, 50);
+        assertEquals(16, randomScores.length); // 2^4 = 16
+
+        // All scores should be between 1 and 50
+        for (int score : randomScores) {
+            assertTrue(score >= 1 && score <= 50);
+        }
+    }
+
+    @Test
+    void testGetRandomScoresWithDifferentParameters() {
+        int[] randomScores = MiniMaxAlgorithm.getRandomScores(2, 10);
+        assertEquals(4, randomScores.length); // 2^2 = 4
+
+        // All scores should be between 1 and 10
+        for (int score : randomScores) {
+            assertTrue(score >= 1 && score <= 10);
+        }
+    }
+
+    @Test
+    void testMainMethod() {
+        // Test that main method runs without errors
+        assertDoesNotThrow(() -> MiniMaxAlgorithm.main(new String[] {}));
+
+        String output = outputStream.toString();
+        assertTrue(output.contains("The best score for"));
+        assertTrue(output.contains("Maximizer"));
+    }
+
+    @Test
+    void testHeightCalculation() {
+        // Test height calculation for different array sizes
+        int[] scores2 = {1, 2};
+        miniMax.setScores(scores2);
+        assertEquals(1, miniMax.getHeight()); // log2(2) = 1
+
+        int[] scores16 = new int[16];
+        miniMax.setScores(scores16);
+        assertEquals(4, miniMax.getHeight()); // log2(16) = 4
+    }
+
+    @Test
+    void testEdgeCaseWithZeroScores() {
+        int[] zeroScores = {0, 0, 0, 0};
+        miniMax.setScores(zeroScores);
+
+        int result = miniMax.miniMax(0, true, 0, false);
+        assertEquals(0, result);
+    }
+
+    @Test
+    void testEdgeCaseWithNegativeScores() {
+        int[] negativeScores = {-5, -2, -8, -1};
+        miniMax.setScores(negativeScores);
+
+        // Tree evaluation with maximizer first:
+        // Level 1 (minimizer): min(-5,-2) = -5, min(-8,-1) = -8
+        // Level 0 (maximizer): max(-5, -8) = -5
+        int result = miniMax.miniMax(0, true, 0, false);
+        assertEquals(-5, result);
+    }
+
+    void tearDown() {
+        System.setOut(originalOut);
+    }
+
+    @Test
+    void testSetScoresWithNegativeLength() {
+        // This test ensures the first condition of isPowerOfTwo (n > 0) is tested
+        // Although we can't directly create an array with negative length,
+        // we can test edge cases around zero and ensure proper validation
+
+        // Test with array length 0 (edge case for n > 0 condition)
+        int[] emptyArray = new int[0];
+        outputStream.reset();
+        miniMax.setScores(emptyArray);
+
+        String output = outputStream.toString();
+        assertTrue(output.contains("The number of scores must be a power of 2."));
+        assertEquals(8, miniMax.getScores().length); // Should remain unchanged
+    }
+
+    @Test
+    void testSetScoresWithLargePowerOfTwo() {
+        // Test with a large power of 2 to ensure the algorithm works correctly
+        int[] largeValidScores = new int[32]; // 32 = 2^5
+        for (int i = 0; i < largeValidScores.length; i++) {
+            largeValidScores[i] = i + 1;
+        }
+
+        miniMax.setScores(largeValidScores);
+        assertArrayEquals(largeValidScores, miniMax.getScores());
+        assertEquals(5, miniMax.getHeight()); // log2(32) = 5
+    }
+
+    @Test
+    void testSetScoresValidEdgeCases() {
+        // Test valid powers of 2 to ensure isPowerOfTwo returns true correctly
+        int[][] validPowersOf2 = {
+            new int[1], // 1 = 2^0
+            new int[2], // 2 = 2^1
+            new int[4], // 4 = 2^2
+            new int[8], // 8 = 2^3
+            new int[16], // 16 = 2^4
+            new int[64] // 64 = 2^6
+        };
+
+        int[] expectedHeights = {0, 1, 2, 3, 4, 6};
+
+        for (int i = 0; i < validPowersOf2.length; i++) {
+            miniMax.setScores(validPowersOf2[i]);
+            assertEquals(validPowersOf2[i].length, miniMax.getScores().length, "Failed for array length: " + validPowersOf2[i].length);
+            assertEquals(expectedHeights[i], miniMax.getHeight(), "Height calculation failed for array length: " + validPowersOf2[i].length);
+        }
+    }
+}

From d8ddb07b7e360cf2bd6efe44f339165f180a3a1a Mon Sep 17 00:00:00 2001
From: Sriram kulkarni <165943146+BEASTSHRIRAM@users.noreply.github.com>
Date: Thu, 2 Oct 2025 13:14:36 +0530
Subject: [PATCH 0968/1338] Added Sum of Squares Lagrange's Four Square
 algorithm implementation (#6583)

* Add Sum of Squares algorithm implementation

* Format code and add Wikipedia URL for Lagrange's theorem

* Fixed clang-format issues

---------

Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 .../com/thealgorithms/maths/SumOfSquares.java | 53 +++++++++++++++
 .../thealgorithms/maths/SumOfSquaresTest.java | 68 +++++++++++++++++++
 2 files changed, 121 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/SumOfSquares.java
 create mode 100644 src/test/java/com/thealgorithms/maths/SumOfSquaresTest.java

diff --git a/src/main/java/com/thealgorithms/maths/SumOfSquares.java b/src/main/java/com/thealgorithms/maths/SumOfSquares.java
new file mode 100644
index 000000000000..c050d5a75f7b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/SumOfSquares.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.maths;
+
+/**
+ * Implementation of Lagrange's Four Square Theorem
+ * Find minimum number of perfect squares that sum to given number
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Lagrange%27s_four-square_theorem">Lagrange's Four Square Theorem</a>
+ * @author BEASTSHRIRAM
+ */
+public final class SumOfSquares {
+
+    private SumOfSquares() {
+        // Utility class
+    }
+
+    /**
+     * Find minimum number of perfect squares that sum to n
+     *
+     * @param n the target number
+     * @return minimum number of squares needed
+     */
+    public static int minSquares(int n) {
+        if (isPerfectSquare(n)) {
+            return 1;
+        }
+
+        for (int i = 1; i * i <= n; i++) {
+            int remaining = n - i * i;
+            if (isPerfectSquare(remaining)) {
+                return 2;
+            }
+        }
+
+        // Legendre's three-square theorem
+        int temp = n;
+        while (temp % 4 == 0) {
+            temp /= 4;
+        }
+        if (temp % 8 == 7) {
+            return 4;
+        }
+
+        return 3;
+    }
+
+    private static boolean isPerfectSquare(int n) {
+        if (n < 0) {
+            return false;
+        }
+        int root = (int) Math.sqrt(n);
+        return root * root == n;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/SumOfSquaresTest.java b/src/test/java/com/thealgorithms/maths/SumOfSquaresTest.java
new file mode 100644
index 000000000000..834fe61a049e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/SumOfSquaresTest.java
@@ -0,0 +1,68 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for SumOfSquares
+ *
+ * @author BEASTSHRIRAM
+ */
+class SumOfSquaresTest {
+
+    @Test
+    void testPerfectSquares() {
+        // Perfect squares should return 1
+        assertEquals(1, SumOfSquares.minSquares(1)); // 1^2
+        assertEquals(1, SumOfSquares.minSquares(4)); // 2^2
+        assertEquals(1, SumOfSquares.minSquares(9)); // 3^2
+        assertEquals(1, SumOfSquares.minSquares(16)); // 4^2
+        assertEquals(1, SumOfSquares.minSquares(25)); // 5^2
+    }
+
+    @Test
+    void testTwoSquares() {
+        // Numbers that can be expressed as sum of two squares
+        assertEquals(2, SumOfSquares.minSquares(2)); // 1^2 + 1^2
+        assertEquals(2, SumOfSquares.minSquares(5)); // 1^2 + 2^2
+        assertEquals(2, SumOfSquares.minSquares(8)); // 2^2 + 2^2
+        assertEquals(2, SumOfSquares.minSquares(10)); // 1^2 + 3^2
+        assertEquals(2, SumOfSquares.minSquares(13)); // 2^2 + 3^2
+    }
+
+    @Test
+    void testThreeSquares() {
+        // Numbers that require exactly three squares
+        assertEquals(3, SumOfSquares.minSquares(3)); // 1^2 + 1^2 + 1^2
+        assertEquals(3, SumOfSquares.minSquares(6)); // 1^2 + 1^2 + 2^2
+        assertEquals(3, SumOfSquares.minSquares(11)); // 1^2 + 1^2 + 3^2
+        assertEquals(3, SumOfSquares.minSquares(12)); // 2^2 + 2^2 + 2^2
+        assertEquals(3, SumOfSquares.minSquares(14)); // 1^2 + 2^2 + 3^2
+    }
+
+    @Test
+    void testFourSquares() {
+        // Numbers that require exactly four squares (form 4^a * (8b + 7))
+        assertEquals(4, SumOfSquares.minSquares(7)); // 1^2 + 1^2 + 1^2 + 2^2
+        assertEquals(4, SumOfSquares.minSquares(15)); // 1^2 + 1^2 + 2^2 + 3^2
+        assertEquals(4, SumOfSquares.minSquares(23)); // 1^2 + 1^2 + 3^2 + 3^2
+        assertEquals(4, SumOfSquares.minSquares(28)); // 4 * 7, so needs 4 squares
+        assertEquals(4, SumOfSquares.minSquares(31)); // 1^2 + 2^2 + 3^2 + 3^2
+    }
+
+    @Test
+    void testLargerNumbers() {
+        // Test some larger numbers
+        assertEquals(1, SumOfSquares.minSquares(100)); // 10^2
+        assertEquals(2, SumOfSquares.minSquares(65)); // 1^2 + 8^2
+        assertEquals(3, SumOfSquares.minSquares(19)); // 1^2 + 3^2 + 3^2
+        assertEquals(4, SumOfSquares.minSquares(60)); // 4 * 15, and 15 = 8*1 + 7
+    }
+
+    @Test
+    void testEdgeCases() {
+        // Test edge case
+        assertEquals(1, SumOfSquares.minSquares(0)); // 0^2
+    }
+}

From 2be984fdf5fab2c2aff81732e5902e6cd7f19213 Mon Sep 17 00:00:00 2001
From: Nithin U <106614289+NithinU2802@users.noreply.github.com>
Date: Thu, 2 Oct 2025 23:27:14 +0530
Subject: [PATCH 0969/1338] To add Implementation of Base64 Algorithm (#6586)

* feat: base64 algorithm implementation

* feat: test coverage implementation of Base64Test.java

* Update DIRECTORY.md

* fix: build and lint fix update

* patch: linter fix

* fix: enforce strict RFC 4648 compliance in Base64 decoding

* fix: enforce strict rfc 4648 compliance in base64 decoding

---------

Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 DIRECTORY.md                                  |   2 +
 .../com/thealgorithms/conversions/Base64.java | 196 ++++++++++++++++++
 .../thealgorithms/conversions/Base64Test.java | 183 ++++++++++++++++
 3 files changed, 381 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/Base64.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/Base64Test.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 8ae7aea61922..b311b10fa177 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -94,6 +94,7 @@
           - 📄 [AnyBaseToAnyBase](src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java)
           - 📄 [AnyBaseToDecimal](src/main/java/com/thealgorithms/conversions/AnyBaseToDecimal.java)
           - 📄 [AnytoAny](src/main/java/com/thealgorithms/conversions/AnytoAny.java)
+          - 📄 [Base64](src/main/java/com/thealgorithms/conversions/Base64.java)
           - 📄 [BinaryToDecimal](src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java)
           - 📄 [BinaryToHexadecimal](src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java)
           - 📄 [BinaryToOctal](src/main/java/com/thealgorithms/conversions/BinaryToOctal.java)
@@ -839,6 +840,7 @@
           - 📄 [AffineConverterTest](src/test/java/com/thealgorithms/conversions/AffineConverterTest.java)
           - 📄 [AnyBaseToDecimalTest](src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java)
           - 📄 [AnytoAnyTest](src/test/java/com/thealgorithms/conversions/AnytoAnyTest.java)
+          - 📄 [Base64Test](src/test/java/com/thealgorithms/conversions/Base64Test.java)
           - 📄 [BinaryToDecimalTest](src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java)
           - 📄 [BinaryToHexadecimalTest](src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java)
           - 📄 [BinaryToOctalTest](src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java)
diff --git a/src/main/java/com/thealgorithms/conversions/Base64.java b/src/main/java/com/thealgorithms/conversions/Base64.java
new file mode 100644
index 000000000000..5219c4ba7f4e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/Base64.java
@@ -0,0 +1,196 @@
+package com.thealgorithms.conversions;
+
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Base64 is a group of binary-to-text encoding schemes that represent binary data
+ * in an ASCII string format by translating it into a radix-64 representation.
+ * Each base64 digit represents exactly 6 bits of data.
+ *
+ * Base64 encoding is commonly used when there is a need to encode binary data
+ * that needs to be stored and transferred over media that are designed to deal
+ * with textual data.
+ *
+ * Wikipedia Reference: https://en.wikipedia.org/wiki/Base64
+ * Author: Nithin U.
+ * Github: https://github.com/NithinU2802
+ */
+
+public final class Base64 {
+
+    // Base64 character set
+    private static final String BASE64_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+    private static final char PADDING_CHAR = '=';
+
+    private Base64() {
+    }
+
+    /**
+     * Encodes the given byte array to a Base64 encoded string.
+     *
+     * @param input the byte array to encode
+     * @return the Base64 encoded string
+     * @throws IllegalArgumentException if input is null
+     */
+    public static String encode(byte[] input) {
+        if (input == null) {
+            throw new IllegalArgumentException("Input cannot be null");
+        }
+
+        if (input.length == 0) {
+            return "";
+        }
+
+        StringBuilder result = new StringBuilder();
+        int padding = 0;
+
+        // Process input in groups of 3 bytes
+        for (int i = 0; i < input.length; i += 3) {
+            // Get up to 3 bytes
+            int byte1 = input[i] & 0xFF;
+            int byte2 = (i + 1 < input.length) ? (input[i + 1] & 0xFF) : 0;
+            int byte3 = (i + 2 < input.length) ? (input[i + 2] & 0xFF) : 0;
+
+            // Calculate padding needed
+            if (i + 1 >= input.length) {
+                padding = 2;
+            } else if (i + 2 >= input.length) {
+                padding = 1;
+            }
+
+            // Combine 3 bytes into a 24-bit number
+            int combined = (byte1 << 16) | (byte2 << 8) | byte3;
+
+            // Extract four 6-bit groups
+            result.append(BASE64_CHARS.charAt((combined >> 18) & 0x3F));
+            result.append(BASE64_CHARS.charAt((combined >> 12) & 0x3F));
+            result.append(BASE64_CHARS.charAt((combined >> 6) & 0x3F));
+            result.append(BASE64_CHARS.charAt(combined & 0x3F));
+        }
+
+        // Replace padding characters
+        if (padding > 0) {
+            result.setLength(result.length() - padding);
+            for (int i = 0; i < padding; i++) {
+                result.append(PADDING_CHAR);
+            }
+        }
+
+        return result.toString();
+    }
+
+    /**
+     * Encodes the given string to a Base64 encoded string using UTF-8 encoding.
+     *
+     * @param input the string to encode
+     * @return the Base64 encoded string
+     * @throws IllegalArgumentException if input is null
+     */
+    public static String encode(String input) {
+        if (input == null) {
+            throw new IllegalArgumentException("Input cannot be null");
+        }
+
+        return encode(input.getBytes(StandardCharsets.UTF_8));
+    }
+
+    /**
+     * Decodes the given Base64 encoded string to a byte array.
+     *
+     * @param input the Base64 encoded string to decode
+     * @return the decoded byte array
+     * @throws IllegalArgumentException if input is null or contains invalid Base64 characters
+     */
+    public static byte[] decode(String input) {
+        if (input == null) {
+            throw new IllegalArgumentException("Input cannot be null");
+        }
+
+        if (input.isEmpty()) {
+            return new byte[0];
+        }
+
+        // Strict RFC 4648 compliance: length must be a multiple of 4
+        if (input.length() % 4 != 0) {
+            throw new IllegalArgumentException("Invalid Base64 input length; must be multiple of 4");
+        }
+
+        // Validate padding: '=' can only appear at the end (last 1 or 2 chars)
+        int firstPadding = input.indexOf('=');
+        if (firstPadding != -1 && firstPadding < input.length() - 2) {
+            throw new IllegalArgumentException("Padding '=' can only appear at the end (last 1 or 2 characters)");
+        }
+
+        List<Byte> result = new ArrayList<>();
+
+        // Process input in groups of 4 characters
+        for (int i = 0; i < input.length(); i += 4) {
+            // Get up to 4 characters
+            int char1 = getBase64Value(input.charAt(i));
+            int char2 = getBase64Value(input.charAt(i + 1));
+            int char3 = input.charAt(i + 2) == '=' ? 0 : getBase64Value(input.charAt(i + 2));
+            int char4 = input.charAt(i + 3) == '=' ? 0 : getBase64Value(input.charAt(i + 3));
+
+            // Combine four 6-bit groups into a 24-bit number
+            int combined = (char1 << 18) | (char2 << 12) | (char3 << 6) | char4;
+
+            // Extract three 8-bit bytes
+            result.add((byte) ((combined >> 16) & 0xFF));
+            if (input.charAt(i + 2) != '=') {
+                result.add((byte) ((combined >> 8) & 0xFF));
+            }
+            if (input.charAt(i + 3) != '=') {
+                result.add((byte) (combined & 0xFF));
+            }
+        }
+
+        // Convert List<Byte> to byte[]
+        byte[] resultArray = new byte[result.size()];
+        for (int i = 0; i < result.size(); i++) {
+            resultArray[i] = result.get(i);
+        }
+
+        return resultArray;
+    }
+
+    /**
+     * Decodes the given Base64 encoded string to a string using UTF-8 encoding.
+     *
+     * @param input the Base64 encoded string to decode
+     * @return the decoded string
+     * @throws IllegalArgumentException if input is null or contains invalid Base64 characters
+     */
+    public static String decodeToString(String input) {
+        if (input == null) {
+            throw new IllegalArgumentException("Input cannot be null");
+        }
+
+        byte[] decodedBytes = decode(input);
+        return new String(decodedBytes, StandardCharsets.UTF_8);
+    }
+
+    /**
+     * Gets the numeric value of a Base64 character.
+     *
+     * @param c the Base64 character
+     * @return the numeric value (0-63)
+     * @throws IllegalArgumentException if character is not a valid Base64 character
+     */
+    private static int getBase64Value(char c) {
+        if (c >= 'A' && c <= 'Z') {
+            return c - 'A';
+        } else if (c >= 'a' && c <= 'z') {
+            return c - 'a' + 26;
+        } else if (c >= '0' && c <= '9') {
+            return c - '0' + 52;
+        } else if (c == '+') {
+            return 62;
+        } else if (c == '/') {
+            return 63;
+        } else {
+            throw new IllegalArgumentException("Invalid Base64 character: " + c);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/Base64Test.java b/src/test/java/com/thealgorithms/conversions/Base64Test.java
new file mode 100644
index 000000000000..fbc220c0ca95
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/Base64Test.java
@@ -0,0 +1,183 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+/**
+ * Test cases for Base64 encoding and decoding.
+ *
+ * Author: Nithin U.
+ * Github: https://github.com/NithinU2802
+ */
+
+class Base64Test {
+
+    @Test
+    void testBase64Alphabet() {
+        // Test that all Base64 characters are handled correctly
+        String allChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+        String encoded = Base64.encode(allChars);
+        String decoded = Base64.decodeToString(encoded);
+        assertEquals(allChars, decoded);
+    }
+
+    @ParameterizedTest
+    @CsvSource({"'', ''", "A, QQ==", "AB, QUI=", "ABC, QUJD", "ABCD, QUJDRA==", "Hello, SGVsbG8=", "'Hello World', SGVsbG8gV29ybGQ=", "'Hello, World!', 'SGVsbG8sIFdvcmxkIQ=='", "'The quick brown fox jumps over the lazy dog', 'VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wcyBvdmVyIHRoZSBsYXp5IGRvZw=='",
+        "123456789, MTIzNDU2Nzg5", "'Base64 encoding test', 'QmFzZTY0IGVuY29kaW5nIHRlc3Q='"})
+    void
+    testStringEncoding(String input, String expected) {
+        assertEquals(expected, Base64.encode(input));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"'', ''", "QQ==, A", "QUI=, AB", "QUJD, ABC", "QUJDRA==, ABCD", "SGVsbG8=, Hello", "'SGVsbG8gV29ybGQ=', 'Hello World'", "'SGVsbG8sIFdvcmxkIQ==', 'Hello, World!'", "'VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wcyBvdmVyIHRoZSBsYXp5IGRvZw==', 'The quick brown fox jumps over the lazy dog'",
+        "MTIzNDU2Nzg5, 123456789", "'QmFzZTY0IGVuY29kaW5nIHRlc3Q=', 'Base64 encoding test'"})
+    void
+    testStringDecoding(String input, String expected) {
+        assertEquals(expected, Base64.decodeToString(input));
+    }
+
+    @Test
+    void testByteArrayEncoding() {
+        byte[] input = {72, 101, 108, 108, 111};
+        String expected = "SGVsbG8=";
+        assertEquals(expected, Base64.encode(input));
+    }
+
+    @Test
+    void testByteArrayDecoding() {
+        String input = "SGVsbG8=";
+        byte[] expected = {72, 101, 108, 108, 111};
+        assertArrayEquals(expected, Base64.decode(input));
+    }
+
+    @Test
+    void testRoundTripEncoding() {
+        String[] testStrings = {"", "A", "AB", "ABC", "Hello, World!", "The quick brown fox jumps over the lazy dog", "1234567890", "Special chars: !@#$%^&*()_+-=[]{}|;:,.<>?",
+            "Unicode: வணக்கம்", // Tamil for "Hello"
+            "Multi-line\nstring\rwith\tdifferent\nwhitespace"};
+
+        for (String original : testStrings) {
+            String encoded = Base64.encode(original);
+            String decoded = Base64.decodeToString(encoded);
+            assertEquals(original, decoded, "Round trip failed for: " + original);
+        }
+    }
+
+    @Test
+    void testRoundTripByteArrayEncoding() {
+        byte[][] testArrays = {{}, {0}, {-1}, {0, 1, 2, 3, 4, 5}, {-128, -1, 0, 1, 127}, {72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33}};
+
+        for (byte[] original : testArrays) {
+            String encoded = Base64.encode(original);
+            byte[] decoded = Base64.decode(encoded);
+            assertArrayEquals(original, decoded, "Round trip failed for byte array");
+        }
+    }
+
+    @Test
+    void testBinaryData() {
+        // Test with binary data that might contain null bytes
+        byte[] binaryData = new byte[256];
+        for (int i = 0; i < 256; i++) {
+            binaryData[i] = (byte) i;
+        }
+
+        String encoded = Base64.encode(binaryData);
+        byte[] decoded = Base64.decode(encoded);
+        assertArrayEquals(binaryData, decoded);
+    }
+
+    @Test
+    void testNullInputEncoding() {
+        assertThrows(IllegalArgumentException.class, () -> Base64.encode((String) null));
+        assertThrows(IllegalArgumentException.class, () -> Base64.encode((byte[]) null));
+    }
+
+    @Test
+    void testNullInputDecoding() {
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode(null));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decodeToString(null));
+    }
+
+    @Test
+    void testInvalidBase64Characters() {
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("SGVsbG8@"));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("SGVsbG8#"));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("SGVsbG8$"));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("SGVsbG8%"));
+    }
+
+    @Test
+    void testInvalidLength() {
+        // Length must be multiple of 4
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("Q"));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("QQ"));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("QQQ"));
+    }
+
+    @Test
+    void testInvalidPaddingPosition() {
+        // '=' can only appear at the end
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("Q=QQ"));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("Q=Q="));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("=QQQ"));
+    }
+
+    @Test
+    void testPaddingVariations() {
+        // Test different padding scenarios '='
+        assertEquals("A", Base64.decodeToString("QQ=="));
+        assertEquals("AB", Base64.decodeToString("QUI="));
+        assertEquals("ABC", Base64.decodeToString("QUJD"));
+    }
+
+    @Test
+    void testPaddingConsistency() {
+        // Ensure that strings requiring different amounts of padding encode/decode correctly
+        String[] testCases = {"A", "AB", "ABC", "ABCD", "ABCDE", "ABCDEF"};
+
+        for (String test : testCases) {
+            String encoded = Base64.encode(test);
+            String decoded = Base64.decodeToString(encoded);
+            assertEquals(test, decoded);
+
+            // Verify padding is correct
+            int expectedPadding = (3 - (test.length() % 3)) % 3;
+            int actualPadding = 0;
+            for (int i = encoded.length() - 1; i >= 0 && encoded.charAt(i) == '='; i--) {
+                actualPadding++;
+            }
+            assertEquals(expectedPadding, actualPadding, "Incorrect padding for: " + test);
+        }
+    }
+
+    @Test
+    void testLargeData() {
+        // Test with larger data to ensure scalability
+        StringBuilder largeString = new StringBuilder();
+        for (int i = 0; i < 1000; i++) {
+            largeString.append("This is a test string for Base64 encoding. ");
+        }
+
+        String original = largeString.toString();
+        String encoded = Base64.encode(original);
+        String decoded = Base64.decodeToString(encoded);
+        assertEquals(original, decoded);
+    }
+
+    @Test
+    void testEmptyAndSingleCharacter() {
+        // Test edge cases
+        assertEquals("", Base64.encode(""));
+        assertEquals("", Base64.decodeToString(""));
+
+        assertEquals("QQ==", Base64.encode("A"));
+        assertEquals("A", Base64.decodeToString("QQ=="));
+    }
+}

From f43ecd573abc2f3e2515bcdd12832174b6febefe Mon Sep 17 00:00:00 2001
From: Sourav Saha <72702534+yashsaha555@users.noreply.github.com>
Date: Thu, 2 Oct 2025 23:45:03 +0530
Subject: [PATCH 0970/1338] feat: add comprehensive test coverage for
 ProcessDetails entity class (#6590)

* feat: add comprehensive test coverage for ProcessDetails entity class (#6588)

- Add ProcessDetailsTest.java with 20 comprehensive test methods
- Cover all constructors, getters, and setters
- Include edge cases: null values, negatives, zeros, max values
- Add real-world scheduling scenario tests
- Ensure 100% line coverage for ProcessDetails class
- Follow project checkstyle rules and conventions

Fixes #6588

* fix: resolve SpotBugs UC_USELESS_OBJECT warning in ProcessDetailsTest

- Add assertions for process1 in testMultipleProcessesIndependence method
- Verify both processes are properly tested for independence
- Ensure all created objects are meaningfully used in tests

Fixes SpotBugs warning: UC_USELESS_OBJECT at line 224

---------

Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 .../devutils/entities/ProcessDetailsTest.java | 288 ++++++++++++++++++
 1 file changed, 288 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/devutils/entities/ProcessDetailsTest.java

diff --git a/src/test/java/com/thealgorithms/devutils/entities/ProcessDetailsTest.java b/src/test/java/com/thealgorithms/devutils/entities/ProcessDetailsTest.java
new file mode 100644
index 000000000000..b5c96c601e4f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/devutils/entities/ProcessDetailsTest.java
@@ -0,0 +1,288 @@
+package com.thealgorithms.devutils.entities;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for ProcessDetails
+ * Tests the ProcessDetails entity used in scheduling algorithms
+ *
+ * @author Sourav Saha (yashsaha555)
+ */
+class ProcessDetailsTest {
+
+    private ProcessDetails processWithPriority;
+    private ProcessDetails processWithoutPriority;
+
+    @BeforeEach
+    void setUp() {
+        // Initialize test objects before each test
+        processWithPriority = new ProcessDetails("P1", 0, 10, 5);
+        processWithoutPriority = new ProcessDetails("P2", 2, 8);
+    }
+
+    @Test
+    void testConstructorWithPriority() {
+        // Test constructor with priority parameter
+        ProcessDetails process = new ProcessDetails("P3", 1, 15, 3);
+
+        assertEquals("P3", process.getProcessId());
+        assertEquals(1, process.getArrivalTime());
+        assertEquals(15, process.getBurstTime());
+        assertEquals(3, process.getPriority());
+        assertEquals(0, process.getWaitingTime()); // Default value
+        assertEquals(0, process.getTurnAroundTimeTime()); // Default value
+    }
+
+    @Test
+    void testConstructorWithoutPriority() {
+        // Test constructor without priority parameter
+        ProcessDetails process = new ProcessDetails("P4", 3, 12);
+
+        assertEquals("P4", process.getProcessId());
+        assertEquals(3, process.getArrivalTime());
+        assertEquals(12, process.getBurstTime());
+        assertEquals(0, process.getPriority()); // Default value
+        assertEquals(0, process.getWaitingTime()); // Default value
+        assertEquals(0, process.getTurnAroundTimeTime()); // Default value
+    }
+
+    @Test
+    void testGetProcessId() {
+        assertEquals("P1", processWithPriority.getProcessId());
+        assertEquals("P2", processWithoutPriority.getProcessId());
+    }
+
+    @Test
+    void testGetArrivalTime() {
+        assertEquals(0, processWithPriority.getArrivalTime());
+        assertEquals(2, processWithoutPriority.getArrivalTime());
+    }
+
+    @Test
+    void testGetBurstTime() {
+        assertEquals(10, processWithPriority.getBurstTime());
+        assertEquals(8, processWithoutPriority.getBurstTime());
+    }
+
+    @Test
+    void testGetWaitingTime() {
+        // Initial waiting time should be 0
+        assertEquals(0, processWithPriority.getWaitingTime());
+        assertEquals(0, processWithoutPriority.getWaitingTime());
+    }
+
+    @Test
+    void testGetTurnAroundTimeTime() {
+        // Initial turnaround time should be 0
+        assertEquals(0, processWithPriority.getTurnAroundTimeTime());
+        assertEquals(0, processWithoutPriority.getTurnAroundTimeTime());
+    }
+
+    @Test
+    void testGetPriority() {
+        assertEquals(5, processWithPriority.getPriority());
+        assertEquals(0, processWithoutPriority.getPriority()); // Default for constructor without priority
+    }
+
+    @Test
+    void testSetProcessId() {
+        processWithPriority.setProcessId("NewP1");
+        assertEquals("NewP1", processWithPriority.getProcessId());
+
+        // Test setting null process ID
+        processWithPriority.setProcessId(null);
+        assertNull(processWithPriority.getProcessId());
+
+        // Test setting empty process ID
+        processWithPriority.setProcessId("");
+        assertEquals("", processWithPriority.getProcessId());
+    }
+
+    @Test
+    void testSetArrivalTime() {
+        processWithPriority.setArrivalTime(5);
+        assertEquals(5, processWithPriority.getArrivalTime());
+
+        // Test setting negative arrival time
+        processWithPriority.setArrivalTime(-1);
+        assertEquals(-1, processWithPriority.getArrivalTime());
+
+        // Test setting zero arrival time
+        processWithPriority.setArrivalTime(0);
+        assertEquals(0, processWithPriority.getArrivalTime());
+    }
+
+    @Test
+    void testSetBurstTime() {
+        processWithPriority.setBurstTime(20);
+        assertEquals(20, processWithPriority.getBurstTime());
+
+        // Test setting zero burst time
+        processWithPriority.setBurstTime(0);
+        assertEquals(0, processWithPriority.getBurstTime());
+
+        // Test setting very large burst time
+        processWithPriority.setBurstTime(Integer.MAX_VALUE);
+        assertEquals(Integer.MAX_VALUE, processWithPriority.getBurstTime());
+    }
+
+    @Test
+    void testSetWaitingTime() {
+        processWithPriority.setWaitingTime(15);
+        assertEquals(15, processWithPriority.getWaitingTime());
+
+        // Test setting negative waiting time
+        processWithPriority.setWaitingTime(-5);
+        assertEquals(-5, processWithPriority.getWaitingTime());
+
+        // Test setting zero waiting time
+        processWithPriority.setWaitingTime(0);
+        assertEquals(0, processWithPriority.getWaitingTime());
+    }
+
+    @Test
+    void testSetTurnAroundTimeTime() {
+        processWithPriority.setTurnAroundTimeTime(25);
+        assertEquals(25, processWithPriority.getTurnAroundTimeTime());
+
+        // Test setting negative turnaround time
+        processWithPriority.setTurnAroundTimeTime(-10);
+        assertEquals(-10, processWithPriority.getTurnAroundTimeTime());
+
+        // Test setting zero turnaround time
+        processWithPriority.setTurnAroundTimeTime(0);
+        assertEquals(0, processWithPriority.getTurnAroundTimeTime());
+    }
+
+    @Test
+    void testCompleteProcessLifecycle() {
+        // Test a complete process lifecycle with realistic scheduling values
+        ProcessDetails process = new ProcessDetails("P5", 0, 10, 2);
+
+        // Simulate process execution
+        process.setWaitingTime(5); // Process waited 5 time units
+        process.setTurnAroundTimeTime(15); // Total time from arrival to completion
+
+        assertEquals("P5", process.getProcessId());
+        assertEquals(0, process.getArrivalTime());
+        assertEquals(10, process.getBurstTime());
+        assertEquals(5, process.getWaitingTime());
+        assertEquals(15, process.getTurnAroundTimeTime());
+        assertEquals(2, process.getPriority());
+    }
+
+    @Test
+    void testProcessWithMinimumValues() {
+        // Test process with minimum possible values
+        ProcessDetails process = new ProcessDetails("", 0, 1, 0);
+
+        assertEquals("", process.getProcessId());
+        assertEquals(0, process.getArrivalTime());
+        assertEquals(1, process.getBurstTime());
+        assertEquals(0, process.getPriority());
+    }
+
+    @Test
+    void testProcessWithMaximumValues() {
+        // Test process with large values
+        ProcessDetails process = new ProcessDetails("LongProcessName", Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE);
+
+        assertEquals("LongProcessName", process.getProcessId());
+        assertEquals(Integer.MAX_VALUE, process.getArrivalTime());
+        assertEquals(Integer.MAX_VALUE, process.getBurstTime());
+        assertEquals(Integer.MAX_VALUE, process.getPriority());
+    }
+
+    @Test
+    void testProcessModificationAfterCreation() {
+        // Test that all fields can be modified after object creation
+        ProcessDetails process = new ProcessDetails("Original", 1, 5, 3);
+
+        // Modify all fields
+        process.setProcessId("Modified");
+        process.setArrivalTime(10);
+        process.setBurstTime(20);
+        process.setWaitingTime(8);
+        process.setTurnAroundTimeTime(28);
+
+        // Verify all modifications
+        assertEquals("Modified", process.getProcessId());
+        assertEquals(10, process.getArrivalTime());
+        assertEquals(20, process.getBurstTime());
+        assertEquals(8, process.getWaitingTime());
+        assertEquals(28, process.getTurnAroundTimeTime());
+        assertEquals(3, process.getPriority()); // Priority has no setter, should remain unchanged
+    }
+
+    @Test
+    void testMultipleProcessesIndependence() {
+        // Test that multiple ProcessDetails objects are independent
+        ProcessDetails process1 = new ProcessDetails("P1", 0, 5, 1);
+        ProcessDetails process2 = new ProcessDetails("P2", 2, 8, 2);
+
+        // Modify first process
+        process1.setWaitingTime(10);
+        process1.setTurnAroundTimeTime(15);
+
+        // Verify first process was modified correctly
+        assertEquals("P1", process1.getProcessId());
+        assertEquals(0, process1.getArrivalTime());
+        assertEquals(5, process1.getBurstTime());
+        assertEquals(1, process1.getPriority());
+        assertEquals(10, process1.getWaitingTime());
+        assertEquals(15, process1.getTurnAroundTimeTime());
+
+        // Verify second process is unchanged
+        assertEquals("P2", process2.getProcessId());
+        assertEquals(2, process2.getArrivalTime());
+        assertEquals(8, process2.getBurstTime());
+        assertEquals(2, process2.getPriority());
+        assertEquals(0, process2.getWaitingTime());
+        assertEquals(0, process2.getTurnAroundTimeTime());
+    }
+
+    @Test
+    void testConstructorParameterOrder() {
+        // Test that constructor parameters are assigned to correct fields
+        ProcessDetails process = new ProcessDetails("TestProcess", 123, 456, 789);
+
+        assertEquals("TestProcess", process.getProcessId());
+        assertEquals(123, process.getArrivalTime());
+        assertEquals(456, process.getBurstTime());
+        assertEquals(789, process.getPriority());
+    }
+
+    @Test
+    void testTypicalSchedulingScenario() {
+        // Test a typical scheduling scenario with multiple processes
+        ProcessDetails[] processes = {new ProcessDetails("P1", 0, 8, 3), new ProcessDetails("P2", 1, 4, 1), new ProcessDetails("P3", 2, 9, 4), new ProcessDetails("P4", 3, 5, 2)};
+
+        // Simulate FCFS scheduling calculations
+        int currentTime = 0;
+        for (ProcessDetails process : processes) {
+            if (currentTime < process.getArrivalTime()) {
+                currentTime = process.getArrivalTime();
+            }
+            process.setWaitingTime(currentTime - process.getArrivalTime());
+            currentTime += process.getBurstTime();
+            process.setTurnAroundTimeTime(process.getWaitingTime() + process.getBurstTime());
+        }
+
+        // Verify calculations
+        assertEquals(0, processes[0].getWaitingTime()); // P1: arrives at 0, starts immediately
+        assertEquals(8, processes[0].getTurnAroundTimeTime()); // P1: 0 + 8
+
+        assertEquals(7, processes[1].getWaitingTime()); // P2: arrives at 1, starts at 8
+        assertEquals(11, processes[1].getTurnAroundTimeTime()); // P2: 7 + 4
+
+        assertEquals(10, processes[2].getWaitingTime()); // P3: arrives at 2, starts at 12
+        assertEquals(19, processes[2].getTurnAroundTimeTime()); // P3: 10 + 9
+
+        assertEquals(18, processes[3].getWaitingTime()); // P4: arrives at 3, starts at 21
+        assertEquals(23, processes[3].getTurnAroundTimeTime()); // P4: 18 + 5
+    }
+}

From 977c9829043b2a25e7dfcacea5929fee4619cb84 Mon Sep 17 00:00:00 2001
From: Anubhav <110095813+Anubhav-pandey004@users.noreply.github.com>
Date: Thu, 2 Oct 2025 23:55:48 +0530
Subject: [PATCH 0971/1338] Add Minimum Window Substring algorithm in Sliding
 Window package (#6553)

* Create MinimumWindowSubstring.java

* Create MinimumWindowSubstringTest.java

* correct MinimumWindowSubstringTest.java

* Added more test cases

* Update MinimumWindowSubstringTest.java

* Update MinimumWindowSubstringTest.java

* Update MinimumWindowSubstringTest.java

* Update MinimumWindowSubstringTest.java

* Update MinimumWindowSubstringTest.java

* Update MinimumWindowSubstringTest.java

* Added test case "AAABBC" "AABC"

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../slidingwindow/MinimumWindowSubstring.java | 69 +++++++++++++++++++
 .../MinimumWindowSubstringTest.java           | 35 ++++++++++
 2 files changed, 104 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/slidingwindow/MinimumWindowSubstring.java
 create mode 100644 src/test/java/com/thealgorithms/slidingwindow/MinimumWindowSubstringTest.java

diff --git a/src/main/java/com/thealgorithms/slidingwindow/MinimumWindowSubstring.java b/src/main/java/com/thealgorithms/slidingwindow/MinimumWindowSubstring.java
new file mode 100644
index 000000000000..c1a5ac067ab5
--- /dev/null
+++ b/src/main/java/com/thealgorithms/slidingwindow/MinimumWindowSubstring.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.slidingwindow;
+
+import java.util.HashMap;
+
+/**
+ * Finds the minimum window substring in 's' that contains all characters of 't'.
+ *
+ * Worst-case performance O(n)
+ * Best-case performance O(n)
+ * Average performance O(n)
+ * Worst-case space complexity O(1)
+ *
+ * @author https://github.com/Chiefpatwal
+ */
+public final class MinimumWindowSubstring {
+    // Prevent instantiation
+    private MinimumWindowSubstring() {
+    }
+
+    /**
+     * Finds the minimum window substring of 's' containing all characters of 't'.
+     *
+     * @param s The input string to search within.
+     * @param t The string with required characters.
+     * @return The minimum window substring, or empty string if not found.
+     */
+    public static String minWindow(String s, String t) {
+        if (s.length() < t.length()) {
+            return "";
+        }
+
+        HashMap<Character, Integer> tFreq = new HashMap<>();
+        for (char c : t.toCharArray()) {
+            tFreq.put(c, tFreq.getOrDefault(c, 0) + 1);
+        }
+
+        HashMap<Character, Integer> windowFreq = new HashMap<>();
+        int left = 0;
+        int right = 0;
+        int minLen = Integer.MAX_VALUE;
+        int count = 0;
+        String result = "";
+
+        while (right < s.length()) {
+            char c = s.charAt(right);
+            windowFreq.put(c, windowFreq.getOrDefault(c, 0) + 1);
+
+            if (tFreq.containsKey(c) && windowFreq.get(c).intValue() <= tFreq.get(c).intValue()) {
+                count++;
+            }
+
+            while (count == t.length()) {
+                if (right - left + 1 < minLen) {
+                    minLen = right - left + 1;
+                    result = s.substring(left, right + 1);
+                }
+
+                char leftChar = s.charAt(left);
+                windowFreq.put(leftChar, windowFreq.get(leftChar) - 1);
+                if (tFreq.containsKey(leftChar) && windowFreq.get(leftChar) < tFreq.get(leftChar)) {
+                    count--;
+                }
+                left++;
+            }
+            right++;
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/slidingwindow/MinimumWindowSubstringTest.java b/src/test/java/com/thealgorithms/slidingwindow/MinimumWindowSubstringTest.java
new file mode 100644
index 000000000000..2c1534f4bfe6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/slidingwindow/MinimumWindowSubstringTest.java
@@ -0,0 +1,35 @@
+package com.thealgorithms.slidingwindow;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Finds the minimum window substring in {@code s} that contains all characters of {@code t}.
+ *
+ * @param s The input string to search within
+ * @param t The string with required characters
+ * @return The minimum window substring, or empty string if not found
+ * @author  (https://github.com/Chiefpatwal)
+ */
+public class MinimumWindowSubstringTest {
+
+    /**
+     * Tests for MinimumWindowSubstring.minWindow.
+     */
+    @Test
+    public void testMinimumWindowSubstring() {
+        assertEquals("BANC", MinimumWindowSubstring.minWindow("ADOBECODEBANC", "ABC"));
+        assertEquals("a", MinimumWindowSubstring.minWindow("a", "a"));
+        assertEquals("", MinimumWindowSubstring.minWindow("a", "aa"));
+        assertEquals("", MinimumWindowSubstring.minWindow("ADOBECODEBANC", "XYZ"));
+        assertEquals("BC", MinimumWindowSubstring.minWindow("ABCDEF", "BC"));
+        assertEquals("q", MinimumWindowSubstring.minWindow("abcdefghijklmnopqrstuvwxyz", "q"));
+        assertEquals("", MinimumWindowSubstring.minWindow("zzzzzzzzz", "zzzzzzzzzz"));
+        assertEquals("abbbbbcdd", MinimumWindowSubstring.minWindow("aaaaaaaaaaaabbbbbcdd", "abcdd"));
+        assertEquals("ABCDEFG", MinimumWindowSubstring.minWindow("ABCDEFG", "ABCDEFG"));
+        assertEquals("", MinimumWindowSubstring.minWindow("abc", "A"));
+        assertEquals("A", MinimumWindowSubstring.minWindow("aAbBcC", "A"));
+        assertEquals("AABBC", MinimumWindowSubstring.minWindow("AAABBC", "AABC"));
+    }
+}

From 506b6d1ab2fb974fd478414e442dc46db19cdc13 Mon Sep 17 00:00:00 2001
From: Banula Kumarage <63106638+BanulaKumarage@users.noreply.github.com>
Date: Fri, 3 Oct 2025 00:01:19 +0530
Subject: [PATCH 0972/1338] DEV: Implementing Time Conversion Algorithm (#6556)

* Added-time-converter-algorithm

* Updated-java-docs

* Fixed-formatting-issues

* Enhanced-unit-tests

* Fixed-failing-check-style

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../conversions/TimeConverter.java            | 97 +++++++++++++++++++
 .../conversions/TimeConverterTest.java        | 69 +++++++++++++
 2 files changed, 166 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/TimeConverter.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/TimeConverterTest.java

diff --git a/src/main/java/com/thealgorithms/conversions/TimeConverter.java b/src/main/java/com/thealgorithms/conversions/TimeConverter.java
new file mode 100644
index 000000000000..41cae37d7ad1
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/TimeConverter.java
@@ -0,0 +1,97 @@
+package com.thealgorithms.conversions;
+
+import java.util.Locale;
+import java.util.Map;
+
+/**
+ * A utility class to convert between different units of time.
+ *
+ * <p>This class supports conversions between the following units:
+ * <ul>
+ *   <li>seconds</li>
+ *   <li>minutes</li>
+ *   <li>hours</li>
+ *   <li>days</li>
+ *   <li>weeks</li>
+ *   <li>months (approximated as 30.44 days)</li>
+ *   <li>years (approximated as 365.25 days)</li>
+ * </ul>
+ *
+ * <p>The conversion is based on predefined constants in seconds.
+ * Results are rounded to three decimal places for consistency.
+ *
+ * <p>This class is final and cannot be instantiated.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Unit_of_time">Wikipedia: Unit of time</a>
+ */
+public final class TimeConverter {
+
+    private TimeConverter() {
+        // Prevent instantiation
+    }
+
+    /**
+     * Supported time units with their equivalent in seconds.
+     */
+    private enum TimeUnit {
+        SECONDS(1.0),
+        MINUTES(60.0),
+        HOURS(3600.0),
+        DAYS(86400.0),
+        WEEKS(604800.0),
+        MONTHS(2629800.0), // 30.44 days
+        YEARS(31557600.0); // 365.25 days
+
+        private final double seconds;
+
+        TimeUnit(double seconds) {
+            this.seconds = seconds;
+        }
+
+        public double toSeconds(double value) {
+            return value * seconds;
+        }
+
+        public double fromSeconds(double secondsValue) {
+            return secondsValue / seconds;
+        }
+    }
+
+    private static final Map<String, TimeUnit> UNIT_LOOKUP
+        = Map.ofEntries(Map.entry("seconds", TimeUnit.SECONDS), Map.entry("minutes", TimeUnit.MINUTES), Map.entry("hours", TimeUnit.HOURS), Map.entry("days", TimeUnit.DAYS), Map.entry("weeks", TimeUnit.WEEKS), Map.entry("months", TimeUnit.MONTHS), Map.entry("years", TimeUnit.YEARS));
+
+    /**
+     * Converts a time value from one unit to another.
+     *
+     * @param timeValue the numeric value of time to convert; must be non-negative
+     * @param unitFrom the unit of the input value (e.g., "minutes", "hours")
+     * @param unitTo the unit to convert into (e.g., "seconds", "days")
+     * @return the converted value in the target unit, rounded to three decimals
+     * @throws IllegalArgumentException if {@code timeValue} is negative
+     * @throws IllegalArgumentException if either {@code unitFrom} or {@code unitTo} is not supported
+     */
+    public static double convertTime(double timeValue, String unitFrom, String unitTo) {
+        if (timeValue < 0) {
+            throw new IllegalArgumentException("timeValue must be a non-negative number.");
+        }
+
+        TimeUnit from = resolveUnit(unitFrom);
+        TimeUnit to = resolveUnit(unitTo);
+
+        double secondsValue = from.toSeconds(timeValue);
+        double converted = to.fromSeconds(secondsValue);
+
+        return Math.round(converted * 1000.0) / 1000.0;
+    }
+
+    private static TimeUnit resolveUnit(String unit) {
+        if (unit == null) {
+            throw new IllegalArgumentException("Unit cannot be null.");
+        }
+        TimeUnit resolved = UNIT_LOOKUP.get(unit.toLowerCase(Locale.ROOT));
+        if (resolved == null) {
+            throw new IllegalArgumentException("Invalid unit '" + unit + "'. Supported units are: " + UNIT_LOOKUP.keySet());
+        }
+        return resolved;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/TimeConverterTest.java b/src/test/java/com/thealgorithms/conversions/TimeConverterTest.java
new file mode 100644
index 000000000000..4e10318d4563
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/TimeConverterTest.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class TimeConverterTest {
+
+    @ParameterizedTest(name = "{0} {1} -> {2} {3}")
+    @CsvSource({"60, seconds, minutes, 1", "120, seconds, minutes, 2", "2, minutes, seconds, 120", "2, hours, minutes, 120", "1, days, hours, 24", "1, weeks, days, 7", "1, months, days, 30.438", "1, years, days, 365.25", "3600, seconds, hours, 1", "86400, seconds, days, 1",
+        "604800, seconds, weeks, 1", "31557600, seconds, years, 1"})
+    void
+    testValidConversions(double value, String from, String to, double expected) {
+        assertEquals(expected, TimeConverter.convertTime(value, from, to));
+    }
+
+    @Test
+    @DisplayName("Zero conversion returns zero")
+    void testZeroValue() {
+        assertEquals(0.0, TimeConverter.convertTime(0, "seconds", "hours"));
+    }
+
+    @Test
+    @DisplayName("Same-unit conversion returns original value")
+    void testSameUnitConversion() {
+        assertEquals(123.456, TimeConverter.convertTime(123.456, "minutes", "minutes"));
+    }
+
+    @Test
+    @DisplayName("Negative value throws exception")
+    void testNegativeValue() {
+        assertThrows(IllegalArgumentException.class, () -> TimeConverter.convertTime(-5, "seconds", "minutes"));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"lightyears, seconds", "minutes, centuries"})
+    void testInvalidUnits(String from, String to) {
+        assertThrows(IllegalArgumentException.class, () -> TimeConverter.convertTime(10, from, to));
+    }
+
+    @Test
+    @DisplayName("Null unit throws exception")
+    void testNullUnit() {
+        assertThrows(IllegalArgumentException.class, () -> TimeConverter.convertTime(10, null, "seconds"));
+
+        assertThrows(IllegalArgumentException.class, () -> TimeConverter.convertTime(10, "minutes", null));
+
+        assertThrows(IllegalArgumentException.class, () -> TimeConverter.convertTime(10, null, null));
+    }
+
+    static Stream<org.junit.jupiter.params.provider.Arguments> roundTripCases() {
+        return Stream.of(org.junit.jupiter.params.provider.Arguments.of(1.0, "hours", "minutes"), org.junit.jupiter.params.provider.Arguments.of(2.5, "days", "hours"), org.junit.jupiter.params.provider.Arguments.of(1000, "seconds", "minutes"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("roundTripCases")
+    @DisplayName("Round-trip conversion returns original value")
+    void testRoundTripConversion(double value, String from, String to) {
+        double converted = TimeConverter.convertTime(value, from, to);
+        double roundTrip = TimeConverter.convertTime(converted, to, from);
+        assertEquals(Math.round(value * 1000.0) / 1000.0, Math.round(roundTrip * 1000.0) / 1000.0, 0.05);
+    }
+}

From 8d14b492fd9ccf819ac1f3461cdfc21c6d39e3ba Mon Sep 17 00:00:00 2001
From: Yash Rajput <52812070+the-yash-rajput@users.noreply.github.com>
Date: Fri, 3 Oct 2025 15:22:53 +0530
Subject: [PATCH 0973/1338] Added CountBitsFlip algo (#6603)

* Added CountBitsFlip aldo

* checkstyle fix

* checkstyle fix

---------

Co-authored-by: Alx <alexanderklmn@gmail.com>
---
 .../bitmanipulation/CountBitsFlip.java        | 63 +++++++++++++
 .../bitmanipulation/CountBitsFlipTest.java    | 94 +++++++++++++++++++
 2 files changed, 157 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/CountBitsFlip.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/CountBitsFlipTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/CountBitsFlip.java b/src/main/java/com/thealgorithms/bitmanipulation/CountBitsFlip.java
new file mode 100644
index 000000000000..8d2c757e5e0a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/CountBitsFlip.java
@@ -0,0 +1,63 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * Implementation to count number of bits to be flipped to convert A to B
+ *
+ * Problem: Given two numbers A and B, count the number of bits needed to be
+ * flipped to convert A to B.
+ *
+ * Example:
+ * A = 10 (01010 in binary)
+ * B = 20 (10100 in binary)
+ * XOR = 30 (11110 in binary) - positions where bits differ
+ * Answer: 4 bits need to be flipped
+ *
+ * Time Complexity: O(log n) - where n is the number of set bits
+ * Space Complexity: O(1)
+ *
+ *@author [Yash Rajput](https://github.com/the-yash-rajput)
+ */
+public final class CountBitsFlip {
+
+    private CountBitsFlip() {
+        throw new AssertionError("No instances.");
+    }
+
+    /**
+     * Counts the number of bits that need to be flipped to convert a to b
+     *
+     * Algorithm:
+     * 1. XOR a and b to get positions where bits differ
+     * 2. Count the number of set bits in the XOR result
+     * 3. Use Brian Kernighan's algorithm: n & (n-1) removes rightmost set bit
+     *
+     * @param a the source number
+     * @param b the target number
+     * @return the number of bits to flip to convert A to B
+     */
+    public static long countBitsFlip(long a, long b) {
+        int count = 0;
+
+        // XOR gives us positions where bits differ
+        long xorResult = a ^ b;
+
+        // Count set bits using Brian Kernighan's algorithm
+        while (xorResult != 0) {
+            xorResult = xorResult & (xorResult - 1); // Remove rightmost set bit
+            count++;
+        }
+
+        return count;
+    }
+
+    /**
+     * Alternative implementation using Long.bitCount().
+     *
+     * @param a the source number
+     * @param b the target number
+     * @return the number of bits to flip to convert a to b
+     */
+    public static long countBitsFlipAlternative(long a, long b) {
+        return Long.bitCount(a ^ b);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/CountBitsFlipTest.java b/src/test/java/com/thealgorithms/bitmanipulation/CountBitsFlipTest.java
new file mode 100644
index 000000000000..f33fa0fefbc0
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/CountBitsFlipTest.java
@@ -0,0 +1,94 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Random;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for CountBitsFlip.
+ * Covers:
+ *  - simple examples
+ *  - zeros and identical values
+ *  - negative numbers and two's complement edge cases
+ *  - Long.MIN_VALUE / Long.MAX_VALUE
+ *  - randomized consistency checks between two implementations
+ */
+@DisplayName("CountBitsFlip Tests")
+class CountBitsFlipTest {
+
+    @Test
+    @DisplayName("Example: A=10, B=20 => 4 bits")
+    void exampleTenTwenty() {
+        long a = 10L;
+        long b = 20L;
+        long expected = 4L;
+        assertEquals(expected, CountBitsFlip.countBitsFlip(a, b), "Brian Kernighan implementation should return 4");
+        assertEquals(expected, CountBitsFlip.countBitsFlipAlternative(a, b), "Long.bitCount implementation should return 4");
+    }
+
+    @Test
+    @DisplayName("Identical values => 0 bits")
+    void identicalValues() {
+        long a = 123456789L;
+        long b = 123456789L;
+        long expected = 0L;
+        assertEquals(expected, CountBitsFlip.countBitsFlip(a, b));
+        assertEquals(expected, CountBitsFlip.countBitsFlipAlternative(a, b));
+    }
+
+    @Test
+    @DisplayName("Both zeros => 0 bits")
+    void bothZeros() {
+        assertEquals(0L, CountBitsFlip.countBitsFlip(0L, 0L));
+        assertEquals(0L, CountBitsFlip.countBitsFlipAlternative(0L, 0L));
+    }
+
+    @Test
+    @DisplayName("Small example: A=15 (1111), B=8 (1000) => 3 bits")
+    void smallExample() {
+        long a = 15L; // 1111
+        long b = 8L; // 1000
+        long expected = 3L; // differs in three low bits
+        assertEquals(expected, CountBitsFlip.countBitsFlip(a, b));
+        assertEquals(expected, CountBitsFlip.countBitsFlipAlternative(a, b));
+    }
+
+    @Test
+    @DisplayName("Negative values: -1 vs 0 => 64 bits (two's complement all ones)")
+    void negativeVsZero() {
+        long a = -1L;
+        long b = 0L;
+        long expected = 64L; // all 64 bits differ
+        assertEquals(expected, CountBitsFlip.countBitsFlip(a, b));
+        assertEquals(expected, CountBitsFlip.countBitsFlipAlternative(a, b));
+    }
+
+    @Test
+    @DisplayName("Long.MIN_VALUE vs Long.MAX_VALUE => 64 bits")
+    void minMaxLongs() {
+        long a = Long.MIN_VALUE;
+        long b = Long.MAX_VALUE;
+        long expected = 64L; // MAX ^ MIN yields all ones on 64-bit long
+        assertEquals(expected, CountBitsFlip.countBitsFlip(a, b));
+        assertEquals(expected, CountBitsFlip.countBitsFlipAlternative(a, b));
+    }
+
+    @Test
+    @DisplayName("Randomized consistency: both implementations agree across many pairs")
+    void randomizedConsistency() {
+        final int iterations = 1000;
+        final Random rnd = new Random(12345L); // deterministic seed for reproducibility
+
+        for (int i = 0; i < iterations; i++) {
+            long a = rnd.nextLong();
+            long b = rnd.nextLong();
+
+            long res1 = CountBitsFlip.countBitsFlip(a, b);
+            long res2 = CountBitsFlip.countBitsFlipAlternative(a, b);
+
+            assertEquals(res2, res1, () -> String.format("Mismatch for a=%d, b=%d: impl1=%d, impl2=%d", a, b, res1, res2));
+        }
+    }
+}

From 7e29be3ad845a2c31bde4d8dad36b92123faa286 Mon Sep 17 00:00:00 2001
From: JeevaRamanathan <64531160+JeevaRamanathan@users.noreply.github.com>
Date: Fri, 3 Oct 2025 17:03:12 +0530
Subject: [PATCH 0974/1338] Added isogram utility class and unit tests (#6594)

* added isogram utility class and unit tests

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* checking lint issue

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* checking lint issue

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* checking lint issue

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* checking lint issue

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* checking lint issue

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* checking lint issue

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* checking lint issue

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* checking lint issue

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* linter fix

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* fix: HideUtilityClassConstructor

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* linter fix

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* updated isogram class to final

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* pipeline bug fixing

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

* renamed function names and few fixes w.r.t to suggestion

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>

---------

Signed-off-by: JeevaRamanathan <jeevaramanathan.m@infosys.com>
---
 .../com/thealgorithms/strings/Isogram.java    |  92 ++++++++++++++
 .../thealgorithms/strings/IsogramTest.java    | 117 ++++++++++++++++++
 2 files changed, 209 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/Isogram.java
 create mode 100644 src/test/java/com/thealgorithms/strings/IsogramTest.java

diff --git a/src/main/java/com/thealgorithms/strings/Isogram.java b/src/main/java/com/thealgorithms/strings/Isogram.java
new file mode 100644
index 000000000000..b37f085b075d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/Isogram.java
@@ -0,0 +1,92 @@
+package com.thealgorithms.strings;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * An isogram (also called heterogram or nonpattern word) is a word in which no
+ * letter of the word occurs more than once. Each character appears exactly
+ * once.
+ *
+ * For example, the word "uncopyrightable" is the longest common English isogram
+ * with 15 unique letters. Other examples include "dermatoglyphics" (15
+ * letters),
+ * "background" (10 letters), "python" (6 letters), and "keyboard" (8 letters).
+ * But words like "hello" and "programming" are not isograms because some
+ * letters
+ * appear multiple times ('l' appears twice in "hello", while 'r', 'm', 'g'
+ * repeat
+ * in "programming").
+ *
+ * Isograms are particularly valuable in creating substitution ciphers and are
+ * studied in recreational linguistics. A perfect pangram, which uses all 26
+ * letters
+ * of the alphabet exactly once, is a special type of isogram.
+ *
+ * Reference from https://en.wikipedia.org/wiki/Heterogram_(literature)#Isograms
+ */
+public final class Isogram {
+    /**
+     * Private constructor to prevent instantiation of utility class.
+     */
+    private Isogram() {
+    }
+
+    /**
+     * Checks if a string is an isogram using boolean array approach.
+     *
+     * Time Complexity: O(n)
+     * Space Complexity: O(1)
+     *
+     * @param str the input string
+     * @return true if the string is an isogram, false otherwise
+     * @throws IllegalArgumentException if the string contains non-alphabetic
+     *                                  characters
+     */
+    public static boolean isAlphabeticIsogram(String str) {
+        if (str == null || str.isEmpty()) {
+            return true;
+        }
+
+        str = str.toLowerCase();
+
+        for (int i = 0; i < str.length(); i++) {
+            char ch = str.charAt(i);
+            if (ch < 'a' || ch > 'z') {
+                throw new IllegalArgumentException("Input contains non-alphabetic character: '" + ch + "'");
+            }
+        }
+
+        boolean[] seenChars = new boolean[26];
+        for (int i = 0; i < str.length(); i++) {
+            char ch = str.charAt(i);
+            int index = ch - 'a';
+            if (seenChars[index]) {
+                return false;
+            }
+            seenChars[index] = true;
+        }
+        return true;
+    }
+
+    /**
+     * Checks if a string is an isogram using length comparison approach.
+     * Time Complexity: O(n)
+     * Space Complexity: O(k) where k is the number of unique characters
+     *
+     * @param str the input string
+     * @return true if the string is an isogram, false otherwise
+     */
+    public static boolean isFullIsogram(String str) {
+        if (str == null || str.isEmpty()) {
+            return true;
+        }
+        str = str.toLowerCase();
+
+        Set<Character> uniqueChars = new HashSet<>();
+        for (char ch : str.toCharArray()) {
+            uniqueChars.add(ch);
+        }
+        return uniqueChars.size() == str.length();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/IsogramTest.java b/src/test/java/com/thealgorithms/strings/IsogramTest.java
new file mode 100644
index 000000000000..9dd844dc7cf9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/IsogramTest.java
@@ -0,0 +1,117 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class IsogramTest {
+
+    record IsogramTestCase(String input, boolean expected) {
+    }
+
+    private static Stream<IsogramTestCase> isAlphabeticIsogram() {
+        return Stream.of(
+            // Valid isograms (only checks letters)
+            new IsogramTestCase("uncopyrightable", true), new IsogramTestCase("dermatoglyphics", true), new IsogramTestCase("background", true), new IsogramTestCase("python", true), new IsogramTestCase("keyboard", true), new IsogramTestCase("clipboard", true), new IsogramTestCase("flowchart", true),
+            new IsogramTestCase("bankruptcy", true), new IsogramTestCase("computer", true), new IsogramTestCase("algorithms", true),
+
+            // Not isograms - letters repeat
+            new IsogramTestCase("hello", false), new IsogramTestCase("programming", false), new IsogramTestCase("java", false), new IsogramTestCase("coffee", false), new IsogramTestCase("book", false), new IsogramTestCase("letter", false), new IsogramTestCase("mississippi", false),
+            new IsogramTestCase("google", false),
+
+            // Edge cases
+            new IsogramTestCase("", true), new IsogramTestCase("a", true), new IsogramTestCase("ab", true), new IsogramTestCase("abc", true), new IsogramTestCase("aa", false), new IsogramTestCase("abcdefghijklmnopqrstuvwxyz", true),
+
+            // Case insensitive
+            new IsogramTestCase("Python", true), new IsogramTestCase("BACKGROUND", true), new IsogramTestCase("Hello", false), new IsogramTestCase("PROGRAMMING", false));
+    }
+
+    private static Stream<IsogramTestCase> isFullIsogram() {
+        return Stream.of(
+            // Valid isograms (checks all characters)
+            new IsogramTestCase("uncopyrightable", true), new IsogramTestCase("dermatoglyphics", true), new IsogramTestCase("background", true), new IsogramTestCase("python", true), new IsogramTestCase("keyboard", true), new IsogramTestCase("clipboard", true), new IsogramTestCase("flowchart", true),
+            new IsogramTestCase("bankruptcy", true), new IsogramTestCase("computer", true), new IsogramTestCase("algorithms", true),
+
+            // Not isograms - characters repeat
+            new IsogramTestCase("hello", false), new IsogramTestCase("programming", false), new IsogramTestCase("java", false), new IsogramTestCase("coffee", false), new IsogramTestCase("book", false), new IsogramTestCase("letter", false), new IsogramTestCase("mississippi", false),
+            new IsogramTestCase("google", false),
+
+            // Edge cases
+            new IsogramTestCase("", true), new IsogramTestCase("a", true), new IsogramTestCase("ab", true), new IsogramTestCase("abc", true), new IsogramTestCase("aa", false), new IsogramTestCase("abcdefghijklmnopqrstuvwxyz", true),
+
+            // Case insensitive
+            new IsogramTestCase("Python", true), new IsogramTestCase("BACKGROUND", true), new IsogramTestCase("Hello", false), new IsogramTestCase("PROGRAMMING", false),
+
+            // Strings with symbols and numbers
+            new IsogramTestCase("abc@def", true), // all characters unique
+            new IsogramTestCase("test-case", false), // 't', 's', 'e' repeat
+            new IsogramTestCase("python123", true), // all characters unique
+            new IsogramTestCase("hello@123", false), // 'l' repeats
+            new IsogramTestCase("abc123!@#", true), // all characters unique
+            new IsogramTestCase("test123test", false), // 't', 'e', 's' repeat
+            new IsogramTestCase("1234567890", true), // all digits unique
+            new IsogramTestCase("12321", false), // '1' and '2' repeat
+            new IsogramTestCase("!@#$%^&*()", true) // all special characters unique
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("isAlphabeticIsogram")
+    void testIsogramByArray(IsogramTestCase testCase) {
+        assertEquals(testCase.expected(), Isogram.isAlphabeticIsogram(testCase.input()));
+    }
+
+    @ParameterizedTest
+    @MethodSource("isFullIsogram")
+    void testIsogramByLength(IsogramTestCase testCase) {
+        assertEquals(testCase.expected(), Isogram.isFullIsogram(testCase.input()));
+    }
+
+    @Test
+    void testNullInputByArray() {
+        assertTrue(Isogram.isAlphabeticIsogram(null));
+    }
+
+    @Test
+    void testNullInputByLength() {
+        assertTrue(Isogram.isFullIsogram(null));
+    }
+
+    @Test
+    void testEmptyStringByArray() {
+        assertTrue(Isogram.isAlphabeticIsogram(""));
+    }
+
+    @Test
+    void testEmptyStringByLength() {
+        assertTrue(Isogram.isFullIsogram(""));
+    }
+
+    @Test
+    void testAlphabeticIsogramThrowsException() {
+        // Test that IllegalArgumentException is thrown for non-alphabetic characters
+        assertThrows(IllegalArgumentException.class, () -> Isogram.isAlphabeticIsogram("1"));
+        assertThrows(IllegalArgumentException.class, () -> Isogram.isAlphabeticIsogram("@"));
+        assertThrows(IllegalArgumentException.class, () -> Isogram.isAlphabeticIsogram("python!"));
+        assertThrows(IllegalArgumentException.class, () -> Isogram.isAlphabeticIsogram("123algorithm"));
+        assertThrows(IllegalArgumentException.class, () -> Isogram.isAlphabeticIsogram("hello123"));
+        assertThrows(IllegalArgumentException.class, () -> Isogram.isAlphabeticIsogram("!@@#$%^&*()"));
+    }
+
+    @Test
+    void testFullIsogramWithMixedCharacters() {
+        // Test that full isogram method handles all character types without exceptions
+        assertTrue(Isogram.isFullIsogram("abc123"));
+        assertFalse(Isogram.isFullIsogram("test@email")); // 'e' repeats
+        assertFalse(Isogram.isFullIsogram("hello123")); // 'l' repeats
+        assertTrue(Isogram.isFullIsogram("1234567890"));
+        assertFalse(Isogram.isFullIsogram("12321")); // '1' and '2' repeat
+        assertTrue(Isogram.isFullIsogram("!@#$%^&*()"));
+    }
+}

From 6d5170999ad6e6dc20ee57171b50a4be322dd1cb Mon Sep 17 00:00:00 2001
From: Banula Kumarage <63106638+BanulaKumarage@users.noreply.github.com>
Date: Sat, 4 Oct 2025 16:25:26 +0530
Subject: [PATCH 0975/1338] Dev: Added NumberPersistence utility class to find
 multiplicative and additive persistance  (#6612)

* Add NumberPersistence utility class with multiplicative and additive persistence methods

* Fixed identified style issues
---
 .../maths/NumberPersistence.java              | 79 +++++++++++++++++++
 .../maths/NumberPersistenceTest.java          | 42 ++++++++++
 2 files changed, 121 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/NumberPersistence.java
 create mode 100644 src/test/java/com/thealgorithms/maths/NumberPersistenceTest.java

diff --git a/src/main/java/com/thealgorithms/maths/NumberPersistence.java b/src/main/java/com/thealgorithms/maths/NumberPersistence.java
new file mode 100644
index 000000000000..9cc6667dca02
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/NumberPersistence.java
@@ -0,0 +1,79 @@
+package com.thealgorithms.maths;
+
+/**
+ * A utility class for calculating the persistence of a number.
+ *
+ * <p>This class provides methods to calculate:
+ * <ul>
+ *   <li>Multiplicative persistence: The number of steps required to reduce a number to a single digit by multiplying its digits.</li>
+ *   <li>Additive persistence: The number of steps required to reduce a number to a single digit by summing its digits.</li>
+ * </ul>
+ *
+ * <p>This class is final and cannot be instantiated.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Persistence_of_a_number">Wikipedia: Persistence of a number</a>
+ */
+public final class NumberPersistence {
+
+    // Private constructor to prevent instantiation
+    private NumberPersistence() {
+    }
+
+    /**
+     * Calculates the multiplicative persistence of a given number.
+     *
+     * <p>Multiplicative persistence is the number of steps required to reduce a number to a single digit
+     * by multiplying its digits repeatedly.
+     *
+     * @param num the number to calculate persistence for; must be non-negative
+     * @return the multiplicative persistence of the number
+     * @throws IllegalArgumentException if the input number is negative
+     */
+    public static int multiplicativePersistence(int num) {
+        if (num < 0) {
+            throw new IllegalArgumentException("multiplicativePersistence() does not accept negative values");
+        }
+
+        int steps = 0;
+        while (num >= 10) {
+            int product = 1;
+            int temp = num;
+            while (temp > 0) {
+                product *= temp % 10;
+                temp /= 10;
+            }
+            num = product;
+            steps++;
+        }
+        return steps;
+    }
+
+    /**
+     * Calculates the additive persistence of a given number.
+     *
+     * <p>Additive persistence is the number of steps required to reduce a number to a single digit
+     * by summing its digits repeatedly.
+     *
+     * @param num the number to calculate persistence for; must be non-negative
+     * @return the additive persistence of the number
+     * @throws IllegalArgumentException if the input number is negative
+     */
+    public static int additivePersistence(int num) {
+        if (num < 0) {
+            throw new IllegalArgumentException("additivePersistence() does not accept negative values");
+        }
+
+        int steps = 0;
+        while (num >= 10) {
+            int sum = 0;
+            int temp = num;
+            while (temp > 0) {
+                sum += temp % 10;
+                temp /= 10;
+            }
+            num = sum;
+            steps++;
+        }
+        return steps;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/NumberPersistenceTest.java b/src/test/java/com/thealgorithms/maths/NumberPersistenceTest.java
new file mode 100644
index 000000000000..3f7e70167fc2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/NumberPersistenceTest.java
@@ -0,0 +1,42 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class NumberPersistenceTest {
+
+    @ParameterizedTest(name = "multiplicativePersistence({0}) = {1}")
+    @CsvSource({"0, 0", "7, 0", "217, 2", "39, 3", "999, 4"})
+    @DisplayName("Test multiplicative persistence with valid inputs")
+    void testMultiplicativePersistenceValid(int input, int expected) {
+        assertEquals(expected, NumberPersistence.multiplicativePersistence(input));
+    }
+
+    @ParameterizedTest(name = "multiplicativePersistence({0}) throws IllegalArgumentException")
+    @ValueSource(ints = {-1, -100, -9999})
+    @DisplayName("Test multiplicative persistence with negative numbers")
+    void testMultiplicativePersistenceNegative(int input) {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> NumberPersistence.multiplicativePersistence(input));
+        assertEquals("multiplicativePersistence() does not accept negative values", exception.getMessage());
+    }
+
+    @ParameterizedTest(name = "additivePersistence({0}) = {1}")
+    @CsvSource({"0, 0", "5, 0", "199, 3", "999, 2", "1234, 2"})
+    @DisplayName("Test additive persistence with valid inputs")
+    void testAdditivePersistenceValid(int input, int expected) {
+        assertEquals(expected, NumberPersistence.additivePersistence(input));
+    }
+
+    @ParameterizedTest(name = "additivePersistence({0}) throws IllegalArgumentException")
+    @ValueSource(ints = {-1, -100, -9999})
+    @DisplayName("Test additive persistence with negative numbers")
+    void testAdditivePersistenceNegative(int input) {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> NumberPersistence.additivePersistence(input));
+        assertEquals("additivePersistence() does not accept negative values", exception.getMessage());
+    }
+}

From a0b6c52790c9ad85581c91dac666adaf09706147 Mon Sep 17 00:00:00 2001
From: Banula Kumarage <63106638+BanulaKumarage@users.noreply.github.com>
Date: Sat, 4 Oct 2025 19:26:08 +0530
Subject: [PATCH 0976/1338] Dev: Added algorithm to find the nth number in the
 Sylvester Sequence (#6613)

Added algorithm to find the nth number in the SylvesterSequence
---
 .../recursion/SylvesterSequence.java          | 50 ++++++++++++++++++
 .../recursion/SylvesterSequenceTest.java      | 51 +++++++++++++++++++
 2 files changed, 101 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/recursion/SylvesterSequence.java
 create mode 100644 src/test/java/com/thealgorithms/recursion/SylvesterSequenceTest.java

diff --git a/src/main/java/com/thealgorithms/recursion/SylvesterSequence.java b/src/main/java/com/thealgorithms/recursion/SylvesterSequence.java
new file mode 100644
index 000000000000..2b39f66c7936
--- /dev/null
+++ b/src/main/java/com/thealgorithms/recursion/SylvesterSequence.java
@@ -0,0 +1,50 @@
+package com.thealgorithms.recursion;
+
+import java.math.BigInteger;
+
+/**
+ * A utility class for calculating numbers in Sylvester's sequence.
+ *
+ * <p>Sylvester's sequence is a sequence of integers where each term is calculated
+ * using the formula:
+ * <pre>
+ * a(n) = a(n-1) * (a(n-1) - 1) + 1
+ * </pre>
+ * with the first term being 2.
+ *
+ * <p>This class is final and cannot be instantiated.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Sylvester_sequence">Wikipedia: Sylvester sequence</a>
+ */
+public final class SylvesterSequence {
+
+    // Private constructor to prevent instantiation
+    private SylvesterSequence() {
+    }
+
+    /**
+     * Calculates the nth number in Sylvester's sequence.
+     *
+     * <p>The sequence is defined recursively, with the first term being 2:
+     * <pre>
+     * a(1) = 2
+     * a(n) = a(n-1) * (a(n-1) - 1) + 1 for n > 1
+     * </pre>
+     *
+     * @param n the position in the sequence (must be greater than 0)
+     * @return the nth number in Sylvester's sequence
+     * @throws IllegalArgumentException if n is less than or equal to 0
+     */
+    public static BigInteger sylvester(int n) {
+        if (n <= 0) {
+            throw new IllegalArgumentException("sylvester() does not accept negative numbers or zero.");
+        }
+        if (n == 1) {
+            return BigInteger.valueOf(2);
+        } else {
+            BigInteger prev = sylvester(n - 1);
+            // Sylvester sequence formula: a(n) = a(n-1) * (a(n-1) - 1) + 1
+            return prev.multiply(prev.subtract(BigInteger.ONE)).add(BigInteger.ONE);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/recursion/SylvesterSequenceTest.java b/src/test/java/com/thealgorithms/recursion/SylvesterSequenceTest.java
new file mode 100644
index 000000000000..3ea5641ac484
--- /dev/null
+++ b/src/test/java/com/thealgorithms/recursion/SylvesterSequenceTest.java
@@ -0,0 +1,51 @@
+package com.thealgorithms.recursion;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.math.BigInteger;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class SylvesterSequenceTest {
+
+    /**
+     * Provides test cases for valid Sylvester sequence numbers.
+     * Format: { n, expectedValue }
+     */
+    static Stream<Object[]> validSylvesterNumbers() {
+        return Stream.of(new Object[] {1, BigInteger.valueOf(2)}, new Object[] {2, BigInteger.valueOf(3)}, new Object[] {3, BigInteger.valueOf(7)}, new Object[] {4, BigInteger.valueOf(43)}, new Object[] {5, BigInteger.valueOf(1807)}, new Object[] {6, new BigInteger("3263443")},
+            new Object[] {7, new BigInteger("10650056950807")}, new Object[] {8, new BigInteger("113423713055421844361000443")});
+    }
+
+    @ParameterizedTest
+    @MethodSource("validSylvesterNumbers")
+    void testSylvesterValidNumbers(int n, BigInteger expected) {
+        assertEquals(expected, SylvesterSequence.sylvester(n), "Sylvester sequence value mismatch for n=" + n);
+    }
+
+    /**
+     * Test edge case for n <= 0 which should throw IllegalArgumentException
+     */
+    @ParameterizedTest
+    @ValueSource(ints = {0, -1, -10, -100})
+    void testSylvesterInvalidZero(int n) {
+        assertThrows(IllegalArgumentException.class, () -> SylvesterSequence.sylvester(n));
+    }
+
+    /**
+     * Test a larger number to ensure no overflow occurs.
+     */
+    @Test
+    void testSylvesterLargeNumber() {
+        int n = 10;
+        BigInteger result = SylvesterSequence.sylvester(n);
+        assertNotNull(result);
+        assertTrue(result.compareTo(BigInteger.ZERO) > 0, "Result should be positive");
+    }
+}

From e6cb96f39050b7735318983cef486295c790a428 Mon Sep 17 00:00:00 2001
From: Banula Kumarage <63106638+BanulaKumarage@users.noreply.github.com>
Date: Sun, 5 Oct 2025 16:56:13 +0530
Subject: [PATCH 0977/1338] Dev: Added CoordinateConverter for Cartesian and
 Polar coordinate conversions (#6628)

Added CoordinateConverter utility class for Cartesian and Polar coordinate conversions
---
 .../conversions/CoordinateConverter.java      | 57 +++++++++++++++++++
 .../conversions/CoordinateConverterTest.java  | 34 +++++++++++
 2 files changed, 91 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/CoordinateConverter.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/CoordinateConverterTest.java

diff --git a/src/main/java/com/thealgorithms/conversions/CoordinateConverter.java b/src/main/java/com/thealgorithms/conversions/CoordinateConverter.java
new file mode 100644
index 000000000000..2766a3a1cf89
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/CoordinateConverter.java
@@ -0,0 +1,57 @@
+package com.thealgorithms.conversions;
+
+/**
+ * A utility class to convert between Cartesian and Polar coordinate systems.
+ *
+ * <p>This class provides methods to perform the following conversions:
+ * <ul>
+ *   <li>Cartesian to Polar coordinates</li>
+ *   <li>Polar to Cartesian coordinates</li>
+ * </ul>
+ *
+ * <p>The class is final and cannot be instantiated.
+ */
+public final class CoordinateConverter {
+
+    private CoordinateConverter() {
+        // Prevent instantiation
+    }
+
+    /**
+     * Converts Cartesian coordinates to Polar coordinates.
+     *
+     * @param x the x-coordinate in the Cartesian system; must be a finite number
+     * @param y the y-coordinate in the Cartesian system; must be a finite number
+     * @return an array where the first element is the radius (r) and the second element is the angle (theta) in degrees
+     * @throws IllegalArgumentException if x or y is not a finite number
+     */
+    public static double[] cartesianToPolar(double x, double y) {
+        if (!Double.isFinite(x) || !Double.isFinite(y)) {
+            throw new IllegalArgumentException("x and y must be finite numbers.");
+        }
+        double r = Math.sqrt(x * x + y * y);
+        double theta = Math.toDegrees(Math.atan2(y, x));
+        return new double[] {r, theta};
+    }
+
+    /**
+     * Converts Polar coordinates to Cartesian coordinates.
+     *
+     * @param r the radius in the Polar system; must be non-negative
+     * @param thetaDegrees the angle (theta) in degrees in the Polar system; must be a finite number
+     * @return an array where the first element is the x-coordinate and the second element is the y-coordinate in the Cartesian system
+     * @throws IllegalArgumentException if r is negative or thetaDegrees is not a finite number
+     */
+    public static double[] polarToCartesian(double r, double thetaDegrees) {
+        if (r < 0) {
+            throw new IllegalArgumentException("Radius (r) must be non-negative.");
+        }
+        if (!Double.isFinite(thetaDegrees)) {
+            throw new IllegalArgumentException("Theta (angle) must be a finite number.");
+        }
+        double theta = Math.toRadians(thetaDegrees);
+        double x = r * Math.cos(theta);
+        double y = r * Math.sin(theta);
+        return new double[] {x, y};
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/CoordinateConverterTest.java b/src/test/java/com/thealgorithms/conversions/CoordinateConverterTest.java
new file mode 100644
index 000000000000..e41e9160478d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/CoordinateConverterTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class CoordinateConverterTest {
+
+    @ParameterizedTest
+    @CsvSource({"0, 0, 0, 0", "1, 0, 1, 0", "0, 1, 1, 90", "-1, 0, 1, 180", "0, -1, 1, -90", "3, 4, 5, 53.13010235415599"})
+    void testCartesianToPolar(double x, double y, double expectedR, double expectedTheta) {
+        assertArrayEquals(new double[] {expectedR, expectedTheta}, CoordinateConverter.cartesianToPolar(x, y), 1e-9);
+    }
+
+    @ParameterizedTest
+    @CsvSource({"1, 0, 1, 0", "1, 90, 0, 1", "1, 180, -1, 0", "1, -90, 0, -1", "5, 53.13010235415599, 3, 4"})
+    void testPolarToCartesian(double r, double theta, double expectedX, double expectedY) {
+        assertArrayEquals(new double[] {expectedX, expectedY}, CoordinateConverter.polarToCartesian(r, theta), 1e-9);
+    }
+
+    @ParameterizedTest
+    @CsvSource({"NaN, 1", "1, NaN", "Infinity, 1", "1, Infinity", "-Infinity, 1", "1, -Infinity"})
+    void testCartesianToPolarInvalidInputs(double x, double y) {
+        assertThrows(IllegalArgumentException.class, () -> CoordinateConverter.cartesianToPolar(x, y));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"-1, 0", "1, NaN", "1, Infinity", "1, -Infinity"})
+    void testPolarToCartesianInvalidInputs(double r, double theta) {
+        assertThrows(IllegalArgumentException.class, () -> CoordinateConverter.polarToCartesian(r, theta));
+    }
+}

From 9484c7eead8ecf0f35444c7bc96021fa5e45c220 Mon Sep 17 00:00:00 2001
From: Priyanshu Kumar Singh <priyanshu1303d@gmail.com>
Date: Sun, 5 Oct 2025 23:58:06 +0530
Subject: [PATCH 0978/1338] FEAT(geometry): Add Haversine formula and fix build
 issues (#6650)

[FEAT] Implemented Haversine Formula

Co-authored-by: Priyanshu1303d <priyanshu130d@gmail.com>
---
 pom.xml                                       |  3 +-
 .../dynamicprogramming/PartitionProblem.java  |  7 +--
 .../com/thealgorithms/geometry/Haversine.java | 49 +++++++++++++++
 .../thealgorithms/geometry/HaversineTest.java | 60 +++++++++++++++++++
 4 files changed, 112 insertions(+), 7 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/geometry/Haversine.java
 create mode 100644 src/test/java/com/thealgorithms/geometry/HaversineTest.java

diff --git a/pom.xml b/pom.xml
index 2122e6660da3..9049b21e3ba6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -71,8 +71,7 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.14.1</version>
                 <configuration>
-                    <source>21</source>
-                    <target>21</target>
+                    <release>21</release>
                     <compilerArgs>
                         <arg>-Xlint:all</arg>
                         <arg>-Xlint:-auxiliaryclass</arg>
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java b/src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java
index 49c4a0a3a008..8c72fa347f50 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java
@@ -1,3 +1,5 @@
+package com.thealgorithms.dynamicprogramming;
+import java.util.Arrays;
 /**
  * @author Md Asif Joardar
  *
@@ -13,11 +15,6 @@
  *
  * The time complexity of the solution is O(n × sum) and requires O(n × sum) space
  */
-
-package com.thealgorithms.dynamicprogramming;
-
-import java.util.Arrays;
-
 public final class PartitionProblem {
     private PartitionProblem() {
     }
diff --git a/src/main/java/com/thealgorithms/geometry/Haversine.java b/src/main/java/com/thealgorithms/geometry/Haversine.java
new file mode 100644
index 000000000000..fa1799e9f076
--- /dev/null
+++ b/src/main/java/com/thealgorithms/geometry/Haversine.java
@@ -0,0 +1,49 @@
+package com.thealgorithms.geometry;
+/**
+ * This Class implements the Haversine formula to calculate the distance between two points on a sphere (like Earth) from their latitudes and longitudes.
+ *
+ * The Haversine formula is used in navigation and mapping to find the great-circle distance,
+ * which is the shortest distance between two points along the surface of a sphere. It is often
+ * used to calculate the "as the crow flies" distance between two geographical locations.
+ *
+ * The formula is reliable for all distances, including small ones, and avoids issues with
+ * numerical instability that can affect other methods.
+ *
+ * @see "https://en.wikipedia.org/wiki/Haversine_formula" - Wikipedia
+ */
+public final class Haversine {
+
+    // Average radius of Earth in kilometers
+    private static final double EARTH_RADIUS_KM = 6371.0;
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private Haversine() {
+    }
+
+    /**
+     * Calculates the great-circle distance between two points on the earth
+     * (specified in decimal degrees).
+     *
+     * @param lat1 Latitude of the first point in decimal degrees.
+     * @param lon1 Longitude of the first point in decimal degrees.
+     * @param lat2 Latitude of the second point in decimal degrees.
+     * @param lon2 Longitude of the second point in decimal degrees.
+     * @return The distance between the two points in kilometers.
+     */
+    public static double haversine(double lat1, double lon1, double lat2, double lon2) {
+        // Convert latitude and longitude from degrees to radians
+        double dLat = Math.toRadians(lat2 - lat1);
+        double dLon = Math.toRadians(lon2 - lon1);
+
+        double lat1Rad = Math.toRadians(lat1);
+        double lat2Rad = Math.toRadians(lat2);
+
+        // Apply the Haversine formula
+        double a = Math.pow(Math.sin(dLat / 2), 2) + Math.pow(Math.sin(dLon / 2), 2) * Math.cos(lat1Rad) * Math.cos(lat2Rad);
+        double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+
+        return EARTH_RADIUS_KM * c;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/geometry/HaversineTest.java b/src/test/java/com/thealgorithms/geometry/HaversineTest.java
new file mode 100644
index 000000000000..b4dcca30a8ac
--- /dev/null
+++ b/src/test/java/com/thealgorithms/geometry/HaversineTest.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.geometry;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+/**
+ * Unit tests for the Haversine formula implementation.
+ * This class uses parameterized tests to verify the distance calculation
+ * between various geographical coordinates.
+ */
+final class HaversineTest {
+
+    // A small tolerance for comparing double values, since floating-point
+    // arithmetic is not always exact. A 1km tolerance is reasonable for these distances.
+    private static final double DELTA = 1.0;
+
+    /**
+     * Provides test cases for the haversine distance calculation.
+     * Each argument contains: lat1, lon1, lat2, lon2, and the expected distance in kilometers.
+     *
+     * @return a stream of arguments for the parameterized test.
+     */
+    static Stream<Arguments> haversineTestProvider() {
+        return Stream.of(
+            // Case 1: Distance between Paris, France and Tokyo, Japan
+            Arguments.of(48.8566, 2.3522, 35.6895, 139.6917, 9712.0),
+
+            // Case 2: Distance between New York, USA and London, UK
+            Arguments.of(40.7128, -74.0060, 51.5074, -0.1278, 5570.0),
+
+            // Case 3: Zero distance (same point)
+            Arguments.of(52.5200, 13.4050, 52.5200, 13.4050, 0.0),
+
+            // Case 4: Antipodal points (opposite sides of the Earth)
+            // Should be approximately half the Earth's circumference (PI * radius)
+            Arguments.of(0.0, 0.0, 0.0, 180.0, 20015.0));
+    }
+
+    /**
+     * Tests the haversine method with various sets of coordinates.
+     *
+     * @param lat1             Latitude of the first point.
+     * @param lon1             Longitude of the first point.
+     * @param lat2             Latitude of the second point.
+     * @param lon2             Longitude of the second point.
+     * @param expectedDistance The expected distance in kilometers.
+     */
+    @ParameterizedTest
+    @MethodSource("haversineTestProvider")
+    @DisplayName("Test Haversine distance calculation for various coordinates")
+    void testHaversine(double lat1, double lon1, double lat2, double lon2, double expectedDistance) {
+        double actualDistance = Haversine.haversine(lat1, lon1, lat2, lon2);
+        assertEquals(expectedDistance, actualDistance, DELTA);
+    }
+}

From 8ca2d9f8207dc6ef5fe591b59a977ecdc4f50ac8 Mon Sep 17 00:00:00 2001
From: ananya-research <ananya.303.singh@gmail.com>
Date: Mon, 6 Oct 2025 14:14:32 -0400
Subject: [PATCH 0979/1338] Create zero_one_bfs.java (#6560)

* Create zero_one_bfs.java

* Rename zero_one_bfs.java to ZeroOneBfs.java

* Update ZeroOneBfs.java

* Update ZeroOneBfs.java

* Create ZeroOneBfsTest.java

* Update ZeroOneBfsTest.java

---------

Co-authored-by: a <alexanderklmn@gmail.com>
---
 .../com/thealgorithms/graph/ZeroOneBfs.java   | 77 +++++++++++++++++++
 .../thealgorithms/graph/ZeroOneBfsTest.java   | 68 ++++++++++++++++
 2 files changed, 145 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/ZeroOneBfs.java
 create mode 100644 src/test/java/com/thealgorithms/graph/ZeroOneBfsTest.java

diff --git a/src/main/java/com/thealgorithms/graph/ZeroOneBfs.java b/src/main/java/com/thealgorithms/graph/ZeroOneBfs.java
new file mode 100644
index 000000000000..53181a654215
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/ZeroOneBfs.java
@@ -0,0 +1,77 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.Deque;
+import java.util.List;
+
+/**
+ * 0-1 BFS for shortest paths on graphs with edges weighted 0 or 1.
+ *
+ * <p>Time Complexity: O(V + E). Space Complexity: O(V).
+ *
+ * <p>References:
+ * <ul>
+ *   <li>https://cp-algorithms.com/graph/01_bfs.html</li>
+ * </ul>
+ */
+public final class ZeroOneBfs {
+
+    private ZeroOneBfs() {
+        // Utility class; do not instantiate.
+    }
+
+    /**
+     * Computes shortest distances from {@code src} in a graph whose edges have weight 0 or 1.
+     *
+     * @param n the number of vertices, labeled {@code 0..n-1}
+     * @param adj adjacency list; for each vertex u, {@code adj.get(u)} is a list of pairs
+     *            {@code (v, w)} where {@code v} is a neighbor and {@code w} is 0 or 1
+     * @param src the source vertex
+     * @return an array of distances; {@code Integer.MAX_VALUE} denotes unreachable
+     * @throws IllegalArgumentException if {@code n < 0}, {@code src} is out of range,
+     *                                  or any edge has weight other than 0 or 1
+     */
+    public static int[] shortestPaths(int n, List<List<int[]>> adj, int src) {
+        if (n < 0 || src < 0 || src >= n) {
+            throw new IllegalArgumentException("Invalid n or src");
+        }
+        int[] dist = new int[n];
+        Arrays.fill(dist, Integer.MAX_VALUE);
+        Deque<Integer> dq = new ArrayDeque<>();
+
+        dist[src] = 0;
+        dq.addFirst(src);
+
+        while (!dq.isEmpty()) {
+            int u = dq.pollFirst();
+            List<int[]> edges = adj.get(u);
+            if (edges == null) {
+                continue;
+            }
+            for (int[] e : edges) {
+                if (e == null || e.length < 2) {
+                    continue;
+                }
+                int v = e[0];
+                int w = e[1];
+                if (v < 0 || v >= n) {
+                    continue; // ignore bad edges
+                }
+                if (w != 0 && w != 1) {
+                    throw new IllegalArgumentException("Edge weight must be 0 or 1");
+                }
+                int nd = dist[u] + w;
+                if (nd < dist[v]) {
+                    dist[v] = nd;
+                    if (w == 0) {
+                        dq.addFirst(v);
+                    } else {
+                        dq.addLast(v);
+                    }
+                }
+            }
+        }
+        return dist;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/ZeroOneBfsTest.java b/src/test/java/com/thealgorithms/graph/ZeroOneBfsTest.java
new file mode 100644
index 000000000000..5de9eadf0930
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/ZeroOneBfsTest.java
@@ -0,0 +1,68 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class ZeroOneBfsTest {
+
+    // Helper to build adjacency list with capacity n
+    private static List<List<int[]>> makeAdj(int n) {
+        List<List<int[]>> adj = new ArrayList<>(n);
+        for (int i = 0; i < n; i++) {
+            adj.add(new ArrayList<>());
+        }
+        return adj;
+    }
+
+    @Test
+    void simpleLineGraph() {
+        int n = 4;
+        List<List<int[]>> adj = makeAdj(n);
+        // 0 --0--> 1 --1--> 2 --0--> 3
+        adj.get(0).add(new int[] {1, 0});
+        adj.get(1).add(new int[] {2, 1});
+        adj.get(2).add(new int[] {3, 0});
+
+        int[] dist = ZeroOneBfs.shortestPaths(n, adj, 0);
+        assertArrayEquals(new int[] {0, 0, 1, 1}, dist);
+    }
+
+    @Test
+    void parallelEdgesPreferZero() {
+        int n = 3;
+        List<List<int[]>> adj = makeAdj(n);
+        // Two edges 0->1: weight 1 and weight 0. Algorithm should choose 0.
+        adj.get(0).add(new int[] {1, 1});
+        adj.get(0).add(new int[] {1, 0});
+        adj.get(1).add(new int[] {2, 1});
+
+        int[] dist = ZeroOneBfs.shortestPaths(n, adj, 0);
+        assertArrayEquals(new int[] {0, 0, 1}, dist);
+    }
+
+    @Test
+    void unreachableNodes() {
+        int n = 3;
+        List<List<int[]>> adj = makeAdj(n);
+        adj.get(0).add(new int[] {1, 0});
+        int[] dist = ZeroOneBfs.shortestPaths(n, adj, 0);
+        // node 2 unreachable -> Integer.MAX_VALUE
+        assertArrayEquals(new int[] {0, 0, Integer.MAX_VALUE}, dist);
+    }
+
+    @Test
+    void invalidArgs() {
+        int n = 2;
+        List<List<int[]>> adj = makeAdj(n);
+        // invalid weight
+        adj.get(0).add(new int[] {1, 2});
+        assertThrows(IllegalArgumentException.class, () -> ZeroOneBfs.shortestPaths(n, adj, 0));
+        // invalid src
+        assertThrows(IllegalArgumentException.class, () -> ZeroOneBfs.shortestPaths(n, adj, -1));
+        assertThrows(IllegalArgumentException.class, () -> ZeroOneBfs.shortestPaths(n, adj, 2));
+    }
+}

From 9f985b254943747d38037d214e296214bd7f4dad Mon Sep 17 00:00:00 2001
From: Saahil Mahato <mahatosaahil4@gmail.com>
Date: Tue, 7 Oct 2025 00:08:32 +0545
Subject: [PATCH 0980/1338] feat: add euler primality test (#6680)

* feat: add euler primality test

* refactor: use fixed seed

* fix: more unit test coverage

* fix: add mock tests for edge cases

* fix: styling issues

* refactor: remove duplicate tests

* refactor: reduce static imports

* refactor: remove unnecessary tests

* refactor: move to maths package

---------

Co-authored-by: a <alexanderklmn@gmail.com>
---
 .../thealgorithms/maths/EulerPseudoprime.java | 108 ++++++++++++++++++
 .../maths/EulerPseudoprimeTest.java           |  93 +++++++++++++++
 2 files changed, 201 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/EulerPseudoprime.java
 create mode 100644 src/test/java/com/thealgorithms/maths/EulerPseudoprimeTest.java

diff --git a/src/main/java/com/thealgorithms/maths/EulerPseudoprime.java b/src/main/java/com/thealgorithms/maths/EulerPseudoprime.java
new file mode 100644
index 000000000000..9a03f4e21d17
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/EulerPseudoprime.java
@@ -0,0 +1,108 @@
+package com.thealgorithms.maths;
+
+import java.math.BigInteger;
+import java.util.Random;
+
+/**
+ * The {@code EulerPseudoprime} class implements the Euler primality test.
+ *
+ * It is based on Euler’s criterion:
+ * For an odd prime number {@code n} and any integer {@code a} coprime to {@code n}:
+ *   a^((n-1)/2) ≡ (a/n) (mod n)
+ * where (a/n) is the Jacobi symbol.
+ *
+ * This algorithm is a stronger probabilistic test than Fermat’s test.
+ * It may still incorrectly identify a composite as “probably prime” (Euler pseudoprime),
+ * but such cases are rare.
+ */
+public final class EulerPseudoprime {
+
+    private EulerPseudoprime() {
+        // Private constructor to prevent instantiation.
+    }
+
+    private static final Random RANDOM = new Random(1);
+
+    /**
+     * Performs the Euler primality test for a given number.
+     *
+     * @param n     number to test (must be > 2 and odd)
+     * @param trials number of random bases to test
+     * @return {@code true} if {@code n} passes all Euler tests (probably prime),
+     *         {@code false} if composite.
+     */
+    public static boolean isProbablePrime(BigInteger n, int trials) {
+        if (n.compareTo(BigInteger.TWO) < 0) {
+            return false;
+        }
+        if (n.equals(BigInteger.TWO) || n.equals(BigInteger.valueOf(3))) {
+            return true;
+        }
+        if (n.mod(BigInteger.TWO).equals(BigInteger.ZERO)) {
+            return false;
+        }
+
+        for (int i = 0; i < trials; i++) {
+            BigInteger a = uniformRandom(BigInteger.TWO, n.subtract(BigInteger.TWO));
+            BigInteger jacobi = BigInteger.valueOf(jacobiSymbol(a, n));
+            if (jacobi.equals(BigInteger.ZERO)) {
+                return false;
+            }
+
+            BigInteger exp = n.subtract(BigInteger.ONE).divide(BigInteger.TWO);
+            BigInteger modExp = a.modPow(exp, n);
+
+            // Euler's criterion: a^((n-1)/2) ≡ (a/n) (mod n)
+            if (!modExp.equals(jacobi.mod(n))) {
+                return false; // definitely composite
+            }
+        }
+        return true; // probably prime
+    }
+
+    /**
+     * Computes the Jacobi symbol (a/n).
+     * Assumes n is positive and odd.
+     */
+    public static int jacobiSymbol(BigInteger a, BigInteger n) {
+        if (n.signum() <= 0 || n.mod(BigInteger.TWO).equals(BigInteger.ZERO)) {
+            throw new IllegalArgumentException("n must be positive and odd.");
+        }
+
+        int result = 1;
+        a = a.mod(n);
+
+        while (a.compareTo(BigInteger.ZERO) != 0) {
+            while (a.mod(BigInteger.TWO).equals(BigInteger.ZERO)) {
+                a = a.divide(BigInteger.TWO);
+                BigInteger nMod8 = n.mod(BigInteger.valueOf(8));
+                if (nMod8.equals(BigInteger.valueOf(3)) || nMod8.equals(BigInteger.valueOf(5))) {
+                    result = -result;
+                }
+            }
+
+            BigInteger temp = a;
+            a = n;
+            n = temp;
+
+            if (a.mod(BigInteger.valueOf(4)).equals(BigInteger.valueOf(3)) && n.mod(BigInteger.valueOf(4)).equals(BigInteger.valueOf(3))) {
+                result = -result;
+            }
+
+            a = a.mod(n);
+        }
+
+        return n.equals(BigInteger.ONE) ? result : 0;
+    }
+
+    /**
+     * Generates a random BigInteger between {@code min} and {@code max}, inclusive.
+     */
+    private static BigInteger uniformRandom(BigInteger min, BigInteger max) {
+        BigInteger result;
+        do {
+            result = new BigInteger(max.bitLength(), RANDOM);
+        } while (result.compareTo(min) < 0 || result.compareTo(max) > 0);
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/EulerPseudoprimeTest.java b/src/test/java/com/thealgorithms/maths/EulerPseudoprimeTest.java
new file mode 100644
index 000000000000..b4ee0cf0659c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/EulerPseudoprimeTest.java
@@ -0,0 +1,93 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+
+import java.math.BigInteger;
+import org.junit.jupiter.api.Test;
+import org.mockito.MockedStatic;
+import org.mockito.Mockito;
+
+class EulerPseudoprimeTest {
+
+    @Test
+    void testPrimeNumbers() {
+        assertTrue(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(7), 5));
+        assertTrue(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(13), 5));
+        assertTrue(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(101), 5));
+    }
+
+    @Test
+    void testCompositeNumbers() {
+        assertFalse(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(9), 5));
+        assertFalse(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(21), 5));
+        assertFalse(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(221), 5));
+    }
+
+    @Test
+    void testEvenNumbers() {
+        assertFalse(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(4), 5));
+        assertFalse(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(100), 5));
+    }
+
+    @Test
+    void testEdgeCases() {
+        assertFalse(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(0), 5));
+        assertFalse(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(1), 5));
+        assertTrue(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(2), 5));
+        assertTrue(EulerPseudoprime.isProbablePrime(BigInteger.valueOf(3), 5));
+    }
+
+    @Test
+    void testIsProbablePrimeWhenJacobiSymbolIsZero() {
+        try (MockedStatic<EulerPseudoprime> mockedPrimality = Mockito.mockStatic(EulerPseudoprime.class, Mockito.CALLS_REAL_METHODS)) {
+
+            // Mock jacobiSymbol to return 0 to test the branch
+            mockedPrimality.when(() -> EulerPseudoprime.jacobiSymbol(any(BigInteger.class), any(BigInteger.class))).thenReturn(0);
+
+            boolean result = EulerPseudoprime.isProbablePrime(BigInteger.valueOf(15), 1);
+
+            assertFalse(result);
+        }
+    }
+
+    @Test
+    void testJacobiSymbolThrowsForEvenOrNonPositiveN() throws Exception {
+        var method = EulerPseudoprime.class.getDeclaredMethod("jacobiSymbol", BigInteger.class, BigInteger.class);
+
+        // Helper lambda to unwrap InvocationTargetException
+        Runnable invokeJacobi = () -> {
+            try {
+                method.invoke(null, BigInteger.valueOf(2), BigInteger.valueOf(8));
+            } catch (Exception e) {
+                // unwrap
+                Throwable cause = e.getCause();
+                if (cause instanceof IllegalArgumentException) {
+                    throw (IllegalArgumentException) cause;
+                } else {
+                    throw new RuntimeException(e);
+                }
+            }
+        };
+
+        // Now check that it actually throws
+        assertThrows(IllegalArgumentException.class, invokeJacobi::run);
+
+        // Another case: non-positive n
+        Runnable invokeJacobi2 = () -> {
+            try {
+                method.invoke(null, BigInteger.valueOf(5), BigInteger.valueOf(-3));
+            } catch (Exception e) {
+                Throwable cause = e.getCause();
+                if (cause instanceof IllegalArgumentException) {
+                    throw (IllegalArgumentException) cause;
+                } else {
+                    throw new RuntimeException(e);
+                }
+            }
+        };
+        assertThrows(IllegalArgumentException.class, invokeJacobi2::run);
+    }
+}

From 3eb521b158761e3cf56ccf1ba611df2ee45f29cc Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 7 Oct 2025 00:03:56 +0200
Subject: [PATCH 0981/1338] chore(deps): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.6.14 to 7.6.15 (#6686)

chore(deps): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.6.14 to 7.6.15.
- [Commits](https://github.com/mebigfatguy/fb-contrib/commits)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.6.15
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 9049b21e3ba6..938fb41088dc 100644
--- a/pom.xml
+++ b/pom.xml
@@ -127,7 +127,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.14</version>
+                            <version>7.6.15</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

From 79dc71db89c3e4885853185085b2b5d0273f1db9 Mon Sep 17 00:00:00 2001
From: Saahil Mahato <mahatosaahil4@gmail.com>
Date: Wed, 8 Oct 2025 01:27:53 +0545
Subject: [PATCH 0982/1338] feat: add wu's line drawing algorithm (#6695)

* feat: add wu's line drawing algorithm

* refactor: reorganize internal class declaration

---------

Co-authored-by: a <alexanderklmn@gmail.com>
---
 .../com/thealgorithms/geometry/WusLine.java   | 235 ++++++++++++++++++
 .../thealgorithms/geometry/WusLineTest.java   |  90 +++++++
 2 files changed, 325 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/geometry/WusLine.java
 create mode 100644 src/test/java/com/thealgorithms/geometry/WusLineTest.java

diff --git a/src/main/java/com/thealgorithms/geometry/WusLine.java b/src/main/java/com/thealgorithms/geometry/WusLine.java
new file mode 100644
index 000000000000..3539daaf6e5a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/geometry/WusLine.java
@@ -0,0 +1,235 @@
+package com.thealgorithms.geometry;
+
+import java.awt.Point;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The {@code WusLine} class implements Xiaolin Wu's line drawing algorithm,
+ * which produces anti-aliased lines by varying pixel brightness
+ * according to the line's proximity to pixel centers.
+ *
+ * This implementation returns the pixel coordinates along with
+ * their associated intensity values (in range [0.0, 1.0]), allowing
+ * rendering systems to blend accordingly.
+ *
+ * The algorithm works by:
+ * - Computing a line's intersection with pixel boundaries
+ * - Assigning intensity values based on distance from pixel centers
+ * - Drawing pairs of pixels perpendicular to the line's direction
+ *
+ * Reference: Xiaolin Wu, "An Efficient Antialiasing Technique",
+ * Computer Graphics (SIGGRAPH '91 Proceedings).
+ *
+ */
+public final class WusLine {
+
+    private WusLine() {
+        // Utility class; prevent instantiation.
+    }
+
+    /**
+     * Represents a pixel and its intensity for anti-aliased rendering.
+     *
+     * The intensity value determines how bright the pixel should be drawn,
+     * with 1.0 being fully opaque and 0.0 being fully transparent.
+     */
+    public static class Pixel {
+        /** The pixel's coordinate on the screen. */
+        public final Point point;
+
+        /** The pixel's intensity value, clamped to the range [0.0, 1.0]. */
+        public final double intensity;
+
+        /**
+         * Constructs a new Pixel with the given coordinates and intensity.
+         *
+         * @param x the x-coordinate of the pixel
+         * @param y the y-coordinate of the pixel
+         * @param intensity the brightness/opacity of the pixel, will be clamped to [0.0, 1.0]
+         */
+        public Pixel(int x, int y, double intensity) {
+            this.point = new Point(x, y);
+            this.intensity = Math.clamp(intensity, 0.0, 1.0);
+        }
+    }
+
+    /**
+     * Internal class to hold processed endpoint data.
+     */
+    private static class EndpointData {
+        final int xPixel;
+        final int yPixel;
+        final double yEnd;
+        final double xGap;
+
+        EndpointData(int xPixel, int yPixel, double yEnd, double xGap) {
+            this.xPixel = xPixel;
+            this.yPixel = yPixel;
+            this.yEnd = yEnd;
+            this.xGap = xGap;
+        }
+    }
+
+    /**
+     * Draws an anti-aliased line using Wu's algorithm.
+     *
+     * The algorithm produces smooth lines by drawing pairs of pixels at each
+     * x-coordinate (or y-coordinate for steep lines), with intensities based on
+     * the line's distance from pixel centers.
+     *
+     * @param x0 the x-coordinate of the line's start point
+     * @param y0 the y-coordinate of the line's start point
+     * @param x1 the x-coordinate of the line's end point
+     * @param y1 the y-coordinate of the line's end point
+     * @return a list of {@link Pixel} objects representing the anti-aliased line,
+     *         ordered from start to end
+     */
+    public static List<Pixel> drawLine(int x0, int y0, int x1, int y1) {
+        List<Pixel> pixels = new ArrayList<>();
+
+        // Determine if the line is steep (more vertical than horizontal)
+        boolean steep = Math.abs(y1 - y0) > Math.abs(x1 - x0);
+
+        if (steep) {
+            // For steep lines, swap x and y coordinates to iterate along y-axis
+            int temp = x0;
+            x0 = y0;
+            y0 = temp;
+
+            temp = x1;
+            x1 = y1;
+            y1 = temp;
+        }
+
+        if (x0 > x1) {
+            // Ensure we always draw from left to right
+            int temp = x0;
+            x0 = x1;
+            x1 = temp;
+
+            temp = y0;
+            y0 = y1;
+            y1 = temp;
+        }
+
+        // Calculate the line's slope
+        double deltaX = x1 - (double) x0;
+        double deltaY = y1 - (double) y0;
+        double gradient = (deltaX == 0) ? 1.0 : deltaY / deltaX;
+
+        // Process the first endpoint
+        EndpointData firstEndpoint = processEndpoint(x0, y0, gradient, true);
+        addEndpointPixels(pixels, firstEndpoint, steep);
+
+        // Process the second endpoint
+        EndpointData secondEndpoint = processEndpoint(x1, y1, gradient, false);
+        addEndpointPixels(pixels, secondEndpoint, steep);
+
+        // Draw the main line between endpoints
+        drawMainLine(pixels, firstEndpoint, secondEndpoint, gradient, steep);
+
+        return pixels;
+    }
+
+    /**
+     * Processes a line endpoint to determine its pixel coordinates and intensities.
+     *
+     * @param x the x-coordinate of the endpoint
+     * @param y the y-coordinate of the endpoint
+     * @param gradient the slope of the line
+     * @param isStart true if this is the start endpoint, false if it's the end
+     * @return an {@link EndpointData} object containing processed endpoint information
+     */
+    private static EndpointData processEndpoint(double x, double y, double gradient, boolean isStart) {
+        double xEnd = round(x);
+        double yEnd = y + gradient * (xEnd - x);
+        double xGap = isStart ? rfpart(x + 0.5) : fpart(x + 0.5);
+
+        int xPixel = (int) xEnd;
+        int yPixel = (int) Math.floor(yEnd);
+
+        return new EndpointData(xPixel, yPixel, yEnd, xGap);
+    }
+
+    /**
+     * Adds the two endpoint pixels (one above, one below the line) to the pixel list.
+     *
+     * @param pixels the list to add pixels to
+     * @param endpoint the endpoint data containing coordinates and gaps
+     * @param steep true if the line is steep (coordinates should be swapped)
+     */
+    private static void addEndpointPixels(List<Pixel> pixels, EndpointData endpoint, boolean steep) {
+        double fractionalY = fpart(endpoint.yEnd);
+        double complementFractionalY = rfpart(endpoint.yEnd);
+
+        if (steep) {
+            pixels.add(new Pixel(endpoint.yPixel, endpoint.xPixel, complementFractionalY * endpoint.xGap));
+            pixels.add(new Pixel(endpoint.yPixel + 1, endpoint.xPixel, fractionalY * endpoint.xGap));
+        } else {
+            pixels.add(new Pixel(endpoint.xPixel, endpoint.yPixel, complementFractionalY * endpoint.xGap));
+            pixels.add(new Pixel(endpoint.xPixel, endpoint.yPixel + 1, fractionalY * endpoint.xGap));
+        }
+    }
+
+    /**
+     * Draws the main portion of the line between the two endpoints.
+     *
+     * @param pixels the list to add pixels to
+     * @param firstEndpoint the processed start endpoint
+     * @param secondEndpoint the processed end endpoint
+     * @param gradient the slope of the line
+     * @param steep true if the line is steep (coordinates should be swapped)
+     */
+    private static void drawMainLine(List<Pixel> pixels, EndpointData firstEndpoint, EndpointData secondEndpoint, double gradient, boolean steep) {
+        // Start y-intersection after the first endpoint
+        double intersectionY = firstEndpoint.yEnd + gradient;
+
+        // Iterate through x-coordinates between the endpoints
+        for (int x = firstEndpoint.xPixel + 1; x < secondEndpoint.xPixel; x++) {
+            int yFloor = (int) Math.floor(intersectionY);
+            double fractionalPart = fpart(intersectionY);
+            double complementFractionalPart = rfpart(intersectionY);
+
+            if (steep) {
+                pixels.add(new Pixel(yFloor, x, complementFractionalPart));
+                pixels.add(new Pixel(yFloor + 1, x, fractionalPart));
+            } else {
+                pixels.add(new Pixel(x, yFloor, complementFractionalPart));
+                pixels.add(new Pixel(x, yFloor + 1, fractionalPart));
+            }
+
+            intersectionY += gradient;
+        }
+    }
+
+    /**
+     * Returns the fractional part of a number.
+     *
+     * @param x the input number
+     * @return the fractional part (always in range [0.0, 1.0))
+     */
+    private static double fpart(double x) {
+        return x - Math.floor(x);
+    }
+
+    /**
+     * Returns the reverse fractional part of a number (1 - fractional part).
+     *
+     * @param x the input number
+     * @return 1.0 minus the fractional part (always in range (0.0, 1.0])
+     */
+    private static double rfpart(double x) {
+        return 1.0 - fpart(x);
+    }
+
+    /**
+     * Rounds a number to the nearest integer.
+     *
+     * @param x the input number
+     * @return the nearest integer value as a double
+     */
+    private static double round(double x) {
+        return Math.floor(x + 0.5);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/geometry/WusLineTest.java b/src/test/java/com/thealgorithms/geometry/WusLineTest.java
new file mode 100644
index 000000000000..0b7f36859e69
--- /dev/null
+++ b/src/test/java/com/thealgorithms/geometry/WusLineTest.java
@@ -0,0 +1,90 @@
+package com.thealgorithms.geometry;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the {@link WusLine} class.
+ */
+class WusLineTest {
+
+    @Test
+    void testSimpleLineProducesPixels() {
+        List<WusLine.Pixel> pixels = WusLine.drawLine(2, 2, 6, 4);
+        assertFalse(pixels.isEmpty(), "Line should produce non-empty pixel list");
+    }
+
+    @Test
+    void testEndpointsIncluded() {
+        List<WusLine.Pixel> pixels = WusLine.drawLine(0, 0, 5, 3);
+        boolean hasStart = pixels.stream().anyMatch(p -> p.point.equals(new java.awt.Point(0, 0)));
+        boolean hasEnd = pixels.stream().anyMatch(p -> p.point.equals(new java.awt.Point(5, 3)));
+        assertTrue(hasStart, "Start point should be represented in the pixel list");
+        assertTrue(hasEnd, "End point should be represented in the pixel list");
+    }
+
+    @Test
+    void testIntensityInRange() {
+        List<WusLine.Pixel> pixels = WusLine.drawLine(1, 1, 8, 5);
+        for (WusLine.Pixel pixel : pixels) {
+            assertTrue(pixel.intensity >= 0.0 && pixel.intensity <= 1.0, "Intensity must be clamped between 0.0 and 1.0");
+        }
+    }
+
+    @Test
+    void testReversedEndpointsProducesSameLine() {
+        List<WusLine.Pixel> forward = WusLine.drawLine(2, 2, 10, 5);
+        List<WusLine.Pixel> backward = WusLine.drawLine(10, 5, 2, 2);
+
+        // They should cover same coordinates (ignoring order)
+        var forwardPoints = forward.stream().map(p -> p.point).collect(java.util.stream.Collectors.toSet());
+        var backwardPoints = backward.stream().map(p -> p.point).collect(java.util.stream.Collectors.toSet());
+
+        assertEquals(forwardPoints, backwardPoints, "Reversing endpoints should yield same line pixels");
+    }
+
+    @Test
+    void testSteepLineHasProperCoverage() {
+        // Steep line: Δy > Δx
+        List<WusLine.Pixel> pixels = WusLine.drawLine(3, 2, 5, 10);
+        assertFalse(pixels.isEmpty());
+        // Expect increasing y values
+        long increasing = 0;
+        for (int i = 1; i < pixels.size(); i++) {
+            if (pixels.get(i).point.y >= pixels.get(i - 1).point.y) {
+                increasing++;
+            }
+        }
+        assertTrue(increasing > pixels.size() / 2, "Steep line should have increasing y coordinates");
+    }
+
+    @Test
+    void testZeroLengthLineUsesDefaultGradient() {
+        // same start and end -> dx == 0 -> gradient should take the (dx == 0) ? 1.0 branch
+        List<WusLine.Pixel> pixels = WusLine.drawLine(3, 3, 3, 3);
+
+        // sanity checks: we produced pixels and the exact point is present
+        assertFalse(pixels.isEmpty(), "Zero-length line should produce at least one pixel");
+        assertTrue(pixels.stream().anyMatch(p -> p.point.equals(new java.awt.Point(3, 3))), "Pixel list should include the single-point coordinate (3,3)");
+    }
+
+    @Test
+    void testHorizontalLineIntensityStable() {
+        List<WusLine.Pixel> pixels = WusLine.drawLine(1, 5, 8, 5);
+
+        // For each x, take the max intensity among pixels with that x (the visible intensity for the column)
+        java.util.Map<Integer, Double> maxIntensityByX = pixels.stream()
+                                                             .collect(java.util.stream.Collectors.groupingBy(p -> p.point.x, java.util.stream.Collectors.mapping(p -> p.intensity, java.util.stream.Collectors.maxBy(Double::compareTo))))
+                                                             .entrySet()
+                                                             .stream()
+                                                             .collect(java.util.stream.Collectors.toMap(java.util.Map.Entry::getKey, e -> e.getValue().orElse(0.0)));
+
+        double avgMaxIntensity = maxIntensityByX.values().stream().mapToDouble(Double::doubleValue).average().orElse(0.0);
+
+        assertTrue(avgMaxIntensity > 0.5, "Average of the maximum per-x intensities should be > 0.5 for a horizontal line");
+    }
+}

From 74647e3f6304f399d412321a956ad86670adf671 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 8 Oct 2025 08:28:55 +0200
Subject: [PATCH 0983/1338] chore(deps): bump github/codeql-action from 3 to 4
 in /.github/workflows (#6701)

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 3 to 4.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v3...v4)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: '4'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index ef4953afc954..3a4cfd829b6b 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v3
+        uses: github/codeql-action/init@v4
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v3
+        uses: github/codeql-action/analyze@v4
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v3
+        uses: github/codeql-action/init@v4
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v3
+        uses: github/codeql-action/analyze@v4
         with:
           category: "/language:actions"
 ...

From c06dc292fe1de8158aab283d7496e094d463a46b Mon Sep 17 00:00:00 2001
From: Dheeraj Kumar <45139709+dheeraj1010@users.noreply.github.com>
Date: Wed, 8 Oct 2025 12:12:58 +0530
Subject: [PATCH 0984/1338] feat(ciphers): Add PermutationCipher
 implementation(enhance #6697) (#6700)

* feat(ciphers): Add PermutationCipher implementation with comprehensive tests

- Implement PermutationCipher class for transposition encryption/decryption
- Add encrypt() and decrypt() methods with permutation key support
- Include robust key validation (1-based positions, no duplicates)
- Implement automatic padding for incomplete blocks using 'X' character
- Add comprehensive error handling with descriptive exceptions
- Create 20+ JUnit test cases covering encryption, decryption, edge cases
- Support various key sizes and text processing (spaces removal, case handling)
- Include detailed JavaDoc documentation with algorithm explanation

Algorithm Details:
- Divides plaintext into blocks based on key length
- Rearranges characters within each block according to permutation positions
- Supports round-trip encryption/decryption with inverse permutation
- Handles edge cases: empty strings, single character keys, padding

Tests include: basic functionality, different key sizes, error validation,
real-world examples, and edge case handling.

* Run PermutationCipherTest using Maven

* refactor(PermutationCipher): clean up code by removing unnecessary whitespace and comments

* fix(tests): remove unnecessary whitespace in test assertion for encryption

* fix(tests): correct indentation in assertion for encryption verification

---------

Co-authored-by: a <alexanderklmn@gmail.com>
---
 .../ciphers/PermutationCipher.java            | 194 +++++++++++
 .../ciphers/PermutationCipherTest.java        | 323 ++++++++++++++++++
 2 files changed, 517 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/PermutationCipher.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/PermutationCipherTest.java

diff --git a/src/main/java/com/thealgorithms/ciphers/PermutationCipher.java b/src/main/java/com/thealgorithms/ciphers/PermutationCipher.java
new file mode 100644
index 000000000000..ce443545db1d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/PermutationCipher.java
@@ -0,0 +1,194 @@
+package com.thealgorithms.ciphers;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * A Java implementation of Permutation Cipher.
+ * It is a type of transposition cipher in which the plaintext is divided into blocks
+ * and the characters within each block are rearranged according to a fixed permutation key.
+ *
+ * For example, with key {3, 1, 2} and plaintext "HELLO", the text is divided into blocks
+ * of 3 characters: "HEL" and "LO" (with padding). The characters are then rearranged
+ * according to the key positions.
+ *
+ * @author GitHub Copilot
+ */
+public class PermutationCipher {
+
+    private static final char PADDING_CHAR = 'X';
+
+    /**
+     * Encrypts the given plaintext using the permutation cipher with the specified key.
+     *
+     * @param plaintext the text to encrypt
+     * @param key the permutation key (array of integers representing positions)
+     * @return the encrypted text
+     * @throws IllegalArgumentException if the key is invalid
+     */
+    public String encrypt(String plaintext, int[] key) {
+        validateKey(key);
+
+        if (plaintext == null || plaintext.isEmpty()) {
+            return plaintext;
+        }
+
+        // Remove spaces and convert to uppercase for consistent processing
+        String cleanText = plaintext.replaceAll("\\s+", "").toUpperCase();
+
+        // Pad the text to make it divisible by key length
+        String paddedText = padText(cleanText, key.length);
+
+        StringBuilder encrypted = new StringBuilder();
+
+        // Process text in blocks of key length
+        for (int i = 0; i < paddedText.length(); i += key.length) {
+            String block = paddedText.substring(i, Math.min(i + key.length, paddedText.length()));
+            encrypted.append(permuteBlock(block, key));
+        }
+
+        return encrypted.toString();
+    }
+
+    /**
+     * Decrypts the given ciphertext using the permutation cipher with the specified key.
+     *
+     * @param ciphertext the text to decrypt
+     * @param key the permutation key (array of integers representing positions)
+     * @return the decrypted text
+     * @throws IllegalArgumentException if the key is invalid
+     */
+    public String decrypt(String ciphertext, int[] key) {
+        validateKey(key);
+
+        if (ciphertext == null || ciphertext.isEmpty()) {
+            return ciphertext;
+        }
+
+        // Create the inverse permutation
+        int[] inverseKey = createInverseKey(key);
+
+        StringBuilder decrypted = new StringBuilder();
+
+        // Process text in blocks of key length
+        for (int i = 0; i < ciphertext.length(); i += key.length) {
+            String block = ciphertext.substring(i, Math.min(i + key.length, ciphertext.length()));
+            decrypted.append(permuteBlock(block, inverseKey));
+        }
+
+        // Remove padding characters from the end
+        return removePadding(decrypted.toString());
+    }
+    /**
+     * Validates that the permutation key is valid.
+     * A valid key must contain all integers from 1 to n exactly once, where n is the key length.
+     *
+     * @param key the permutation key to validate
+     * @throws IllegalArgumentException if the key is invalid
+     */
+    private void validateKey(int[] key) {
+        if (key == null || key.length == 0) {
+            throw new IllegalArgumentException("Key cannot be null or empty");
+        }
+
+        Set<Integer> keySet = new HashSet<>();
+        for (int position : key) {
+            if (position < 1 || position > key.length) {
+                throw new IllegalArgumentException("Key must contain integers from 1 to " + key.length);
+            }
+            if (!keySet.add(position)) {
+                throw new IllegalArgumentException("Key must contain each position exactly once");
+            }
+        }
+    }
+
+    /**
+     * Pads the text with padding characters to make its length divisible by the block size.
+     *
+     * @param text the text to pad
+     * @param blockSize the size of each block
+     * @return the padded text
+     */
+    private String padText(String text, int blockSize) {
+        int remainder = text.length() % blockSize;
+        if (remainder == 0) {
+            return text;
+        }
+
+        int paddingNeeded = blockSize - remainder;
+        StringBuilder padded = new StringBuilder(text);
+        for (int i = 0; i < paddingNeeded; i++) {
+            padded.append(PADDING_CHAR);
+        }
+
+        return padded.toString();
+    }
+    /**
+     * Applies the permutation to a single block of text.
+     *
+     * @param block the block to permute
+     * @param key the permutation key
+     * @return the permuted block
+     */
+    private String permuteBlock(String block, int[] key) {
+        if (block.length() != key.length) {
+            // Handle case where block is shorter than key (shouldn't happen with proper padding)
+            block = padText(block, key.length);
+        }
+
+        char[] result = new char[key.length];
+        char[] blockChars = block.toCharArray();
+
+        for (int i = 0; i < key.length; i++) {
+            // Key positions are 1-based, so subtract 1 for 0-based array indexing
+            result[i] = blockChars[key[i] - 1];
+        }
+
+        return new String(result);
+    }
+
+    /**
+     * Creates the inverse permutation key for decryption.
+     *
+     * @param key the original permutation key
+     * @return the inverse key
+     */
+    private int[] createInverseKey(int[] key) {
+        int[] inverse = new int[key.length];
+
+        for (int i = 0; i < key.length; i++) {
+            // The inverse key maps each position to where it should go
+            inverse[key[i] - 1] = i + 1;
+        }
+
+        return inverse;
+    }
+
+    /**
+     * Removes padding characters from the end of the decrypted text.
+     *
+     * @param text the text to remove padding from
+     * @return the text without padding
+     */
+    private String removePadding(String text) {
+        if (text.isEmpty()) {
+            return text;
+        }
+
+        int i = text.length() - 1;
+        while (i >= 0 && text.charAt(i) == PADDING_CHAR) {
+            i--;
+        }
+
+        return text.substring(0, i + 1);
+    }
+
+    /**
+     * Gets the padding character used by this cipher.
+     *
+     * @return the padding character
+     */
+    public char getPaddingChar() {
+        return PADDING_CHAR;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/PermutationCipherTest.java b/src/test/java/com/thealgorithms/ciphers/PermutationCipherTest.java
new file mode 100644
index 000000000000..4ba6787cc97e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/PermutationCipherTest.java
@@ -0,0 +1,323 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class PermutationCipherTest {
+
+    private final PermutationCipher cipher = new PermutationCipher();
+
+    @Test
+    void testBasicEncryption() {
+        // given
+        String plaintext = "HELLO";
+        int[] key = {3, 1, 2}; // Move 3rd position to 1st, 1st to 2nd, 2nd to 3rd
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+
+        // then
+        // "HELLO" becomes "HEL" + "LOX" (padded)
+        // "HEL" with key {3,1,2} becomes "LHE" (L=3rd, H=1st, E=2nd)
+        // "LOX" with key {3,1,2} becomes "XLO" (X=3rd, L=1st, O=2nd)
+        assertEquals("LHEXLO", encrypted);
+    }
+
+    @Test
+    void testBasicDecryption() {
+        // given
+        String ciphertext = "LHEXLO";
+        int[] key = {3, 1, 2};
+
+        // when
+        String decrypted = cipher.decrypt(ciphertext, key);
+
+        // then
+        assertEquals("HELLO", decrypted);
+    }
+
+    @Test
+    void testEncryptDecryptRoundTrip() {
+        // given
+        String plaintext = "THIS IS A TEST MESSAGE";
+        int[] key = {4, 2, 1, 3};
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals("THISISATESTMESSAGE", decrypted); // Spaces are removed during encryption
+    }
+
+    @Test
+    void testSingleCharacterKey() {
+        // given
+        String plaintext = "ABCDEF";
+        int[] key = {1}; // Identity permutation
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals("ABCDEF", encrypted); // Should remain unchanged
+        assertEquals("ABCDEF", decrypted);
+    }
+
+    @Test
+    void testLargerKey() {
+        // given
+        String plaintext = "PERMUTATION";
+        int[] key = {5, 3, 1, 4, 2}; // 5-character permutation
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals("PERMUTATION", decrypted);
+    }
+
+    @Test
+    void testExactBlockSize() {
+        // given
+        String plaintext = "ABCDEF"; // Length 6, divisible by key length 3
+        int[] key = {2, 3, 1};
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals("ABCDEF", decrypted);
+    }
+
+    @Test
+    void testEmptyString() {
+        // given
+        String plaintext = "";
+        int[] key = {2, 1, 3};
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals("", encrypted);
+        assertEquals("", decrypted);
+    }
+
+    @Test
+    void testNullString() {
+        // given
+        String plaintext = null;
+        int[] key = {2, 1, 3};
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals(null, encrypted);
+        assertEquals(null, decrypted);
+    }
+
+    @Test
+    void testStringWithSpaces() {
+        // given
+        String plaintext = "A B C D E F";
+        int[] key = {2, 1};
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals("ABCDEF", decrypted); // Spaces should be removed
+    }
+
+    @Test
+    void testLowercaseConversion() {
+        // given
+        String plaintext = "hello world";
+        int[] key = {3, 1, 2};
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals("HELLOWORLD", decrypted); // Should be converted to uppercase
+    }
+
+    @Test
+    void testInvalidKeyNull() {
+        // given
+        String plaintext = "HELLO";
+        int[] key = null;
+
+        // when & then
+        assertThrows(IllegalArgumentException.class, () -> cipher.encrypt(plaintext, key));
+        assertThrows(IllegalArgumentException.class, () -> cipher.decrypt(plaintext, key));
+    }
+
+    @Test
+    void testInvalidKeyEmpty() {
+        // given
+        String plaintext = "HELLO";
+        int[] key = {};
+
+        // when & then
+        assertThrows(IllegalArgumentException.class, () -> cipher.encrypt(plaintext, key));
+        assertThrows(IllegalArgumentException.class, () -> cipher.decrypt(plaintext, key));
+    }
+
+    @Test
+    void testInvalidKeyOutOfRange() {
+        // given
+        String plaintext = "HELLO";
+        int[] key = {1, 2, 4}; // 4 is out of range for key length 3
+
+        // when & then
+        assertThrows(IllegalArgumentException.class, () -> cipher.encrypt(plaintext, key));
+        assertThrows(IllegalArgumentException.class, () -> cipher.decrypt(plaintext, key));
+    }
+
+    @Test
+    void testInvalidKeyZero() {
+        // given
+        String plaintext = "HELLO";
+        int[] key = {0, 1, 2}; // 0 is invalid (should be 1-based)
+
+        // when & then
+        assertThrows(IllegalArgumentException.class, () -> cipher.encrypt(plaintext, key));
+        assertThrows(IllegalArgumentException.class, () -> cipher.decrypt(plaintext, key));
+    }
+
+    @Test
+    void testInvalidKeyDuplicate() {
+        // given
+        String plaintext = "HELLO";
+        int[] key = {1, 2, 2}; // Duplicate position
+
+        // when & then
+        assertThrows(IllegalArgumentException.class, () -> cipher.encrypt(plaintext, key));
+        assertThrows(IllegalArgumentException.class, () -> cipher.decrypt(plaintext, key));
+    }
+
+    @Test
+    void testInvalidKeyMissingPosition() {
+        // given
+        String plaintext = "HELLO";
+        int[] key = {1, 3}; // Missing position 2
+
+        // when & then
+        assertThrows(IllegalArgumentException.class, () -> cipher.encrypt(plaintext, key));
+        assertThrows(IllegalArgumentException.class, () -> cipher.decrypt(plaintext, key));
+    }
+
+    @Test
+    void testReverseKey() {
+        // given
+        String plaintext = "ABCD";
+        int[] key = {4, 3, 2, 1}; // Reverse order
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals("DCBA", encrypted); // Should be reversed
+        assertEquals("ABCD", decrypted);
+    }
+
+    @Test
+    void testSpecificExampleFromDescription() {
+        // given
+        String plaintext = "HELLO";
+        int[] key = {3, 1, 2};
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+
+        // then
+        // Block 1: "HEL" -> positions {3,1,2} -> "LHE"
+        // Block 2: "LOX" -> positions {3,1,2} -> "XLO"
+        assertEquals("LHEXLO", encrypted);
+        // Verify decryption
+        String decrypted = cipher.decrypt(encrypted, key);
+        assertEquals("HELLO", decrypted);
+    }
+
+    @Test
+    void testPaddingCharacterGetter() {
+        // when
+        char paddingChar = cipher.getPaddingChar();
+
+        // then
+        assertEquals('X', paddingChar);
+    }
+
+    @Test
+    void testLongText() {
+        // given
+        String plaintext = "THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG";
+        int[] key = {4, 1, 3, 2};
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals("THEQUICKBROWNFOXJUMPSOVERTHELAZYDOG", decrypted);
+    }
+
+    @Test
+    void testIdentityPermutation() {
+        // given
+        String plaintext = "IDENTITY";
+        int[] key = {1, 2, 3, 4}; // Identity permutation
+
+        // when
+        String encrypted = cipher.encrypt(plaintext, key);
+        String decrypted = cipher.decrypt(encrypted, key);
+
+        // then
+        assertEquals("IDENTITY", encrypted); // Should remain unchanged
+        assertEquals("IDENTITY", decrypted);
+    }
+
+    @Test
+    void testEmptyStringRemovePadding() {
+        // given - Test to cover line 178 (empty string case in removePadding)
+        String ciphertext = "";
+        int[] key = {2, 1, 3};
+
+        // when
+        String decrypted = cipher.decrypt(ciphertext, key);
+
+        // then
+        assertEquals("", decrypted); // Should return empty string directly
+    }
+
+    @Test
+    void testBlockShorterThanKey() {
+        // given - Test to cover line 139 (block length != key length case)
+        // This is a defensive case where permuteBlock might receive a block shorter than key
+        // We can test this by manually creating a scenario with malformed ciphertext
+        String malformedCiphertext = "AB"; // Length 2, but key length is 3
+        int[] key = {3, 1, 2}; // Key length is 3
+
+        // when - This should trigger the padding logic in permuteBlock during decryption
+        String decrypted = cipher.decrypt(malformedCiphertext, key);
+
+        // then - The method should handle the short block gracefully
+        // "AB" gets padded to "ABX", then permuted with inverse key {2,3,1}
+        // inverse key {2,3,1} means: pos 2→1st, pos 3→2nd, pos 1→3rd = "BXA"
+        // Padding removal only removes trailing X's, so "BXA" remains as is
+        assertEquals("BXA", decrypted);
+    }
+}

From 596302b80e5c0c3a9b4a240090e7a17b1370b080 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 8 Oct 2025 14:31:32 +0300
Subject: [PATCH 0985/1338] chore(deps): bump gitpod/workspace-java-21 from
 2025-08-25-18-17-39 to 2025-10-06-13-14-25 (#6685)

chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2025-08-25-18-17-39 to 2025-10-06-13-14-25.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-version: 2025-10-06-13-14-25
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: a <alexanderklmn@gmail.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index ef76c6fc68a6..4195f928d1bc 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2025-08-25-18-17-39
+FROM gitpod/workspace-java-21:2025-10-06-13-14-25
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 959ced90762e938f690213d7e6b01aad194ed91a Mon Sep 17 00:00:00 2001
From: Sriram kulkarni <165943146+BEASTSHRIRAM@users.noreply.github.com>
Date: Wed, 8 Oct 2025 17:21:44 +0530
Subject: [PATCH 0986/1338] Added mos algorithm and dice thrower (#6591)

* Add Sum of Squares algorithm implementation

* Format code and add Wikipedia URL for Lagrange's theorem

* Fixed clang-format issues

* Added Mo's Algorithm and DiceThrower recursive algorithms

- Mo's Algorithm: Square root decomposition for offline range queries(Imp in CP)
- DiceThrower: Recursive backtracking for dice combinations(very imp)
- Both algorithms include comprehensive test suites
- Formatted with clang-format and i follow contribution guidelines

* Fixed checkstyle violation

* Fixed SpotBugs issue

* Added in PMD exclusions

* Improved test coverage for better Codecov scores.

* Fixed clang-format issues in test files

* Add Mo's Algorithm and DiceThrower algorithms with comprehensive tests
* Fixed PartitionProblem.java documentation comment placement
---
 pmd-exclude.properties                        |   2 +
 .../thealgorithms/others/MosAlgorithm.java    | 260 ++++++++++++++++++
 .../thealgorithms/recursion/DiceThrower.java  | 113 ++++++++
 .../others/MosAlgorithmTest.java              | 202 ++++++++++++++
 .../recursion/DiceThrowerTest.java            | 223 +++++++++++++++
 5 files changed, 800 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/others/MosAlgorithm.java
 create mode 100644 src/main/java/com/thealgorithms/recursion/DiceThrower.java
 create mode 100644 src/test/java/com/thealgorithms/others/MosAlgorithmTest.java
 create mode 100644 src/test/java/com/thealgorithms/recursion/DiceThrowerTest.java

diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index 4c0ed625d884..a3c95b12fa4b 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -88,12 +88,14 @@ com.thealgorithms.others.LinearCongruentialGenerator=UselessMainMethod
 com.thealgorithms.others.Luhn=UnnecessaryFullyQualifiedName,UselessMainMethod
 com.thealgorithms.others.Mandelbrot=UselessMainMethod,UselessParentheses
 com.thealgorithms.others.MiniMaxAlgorithm=UselessMainMethod,UselessParentheses
+com.thealgorithms.others.MosAlgorithm=UselessMainMethod
 com.thealgorithms.others.PageRank=UselessMainMethod,UselessParentheses
 com.thealgorithms.others.PerlinNoise=UselessMainMethod,UselessParentheses
 com.thealgorithms.others.QueueUsingTwoStacks=UselessParentheses
 com.thealgorithms.others.Trieac=UselessMainMethod,UselessParentheses
 com.thealgorithms.others.Verhoeff=UnnecessaryFullyQualifiedName,UselessMainMethod
 com.thealgorithms.puzzlesandgames.Sudoku=UselessMainMethod
+com.thealgorithms.recursion.DiceThrower=UselessMainMethod
 com.thealgorithms.searches.HowManyTimesRotated=UselessMainMethod
 com.thealgorithms.searches.InterpolationSearch=UselessParentheses
 com.thealgorithms.searches.KMPSearch=UselessParentheses
diff --git a/src/main/java/com/thealgorithms/others/MosAlgorithm.java b/src/main/java/com/thealgorithms/others/MosAlgorithm.java
new file mode 100644
index 000000000000..2d2778339a7a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/others/MosAlgorithm.java
@@ -0,0 +1,260 @@
+package com.thealgorithms.others;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+/**
+ * Mo's Algorithm (Square Root Decomposition) for offline range queries
+ *
+ * Mo's Algorithm is used to answer range queries efficiently when:
+ * 1. Queries can be processed offline (all queries known beforehand)
+ * 2. We can efficiently add/remove elements from current range
+ * 3. The problem has optimal substructure for range operations
+ *
+ * Time Complexity: O((N + Q) * sqrt(N)) where N = array size, Q = number of queries
+ * Space Complexity: O(N + Q)
+ *
+ * @see <a href="https://www.geeksforgeeks.org/dsa/mos-algorithm-query-square-root-decomposition-set-1-introduction/">Mo's Algorithm</a>
+ * @author BEASTSHRIRAM
+ */
+public final class MosAlgorithm {
+
+    /**
+     * Query structure to store range queries
+     */
+    public static class Query {
+        public final int left;
+        public final int right;
+        public final int index; // Original index of query
+        public int result; // Result of the query
+
+        public Query(int left, int right, int index) {
+            this.left = left;
+            this.right = right;
+            this.index = index;
+            this.result = 0;
+        }
+    }
+
+    private MosAlgorithm() {
+        // Utility class
+    }
+
+    /**
+     * Solves range sum queries using Mo's Algorithm
+     *
+     * @param arr the input array
+     * @param queries array of queries to process
+     * @return array of results corresponding to each query
+     */
+    public static int[] solveRangeSumQueries(int[] arr, Query[] queries) {
+        if (arr == null || queries == null || arr.length == 0) {
+            return new int[0];
+        }
+
+        int n = arr.length;
+        int blockSize = (int) Math.sqrt(n);
+
+        // Sort queries using Mo's ordering
+        Arrays.sort(queries, new MoComparator(blockSize));
+
+        // Initialize variables for current range
+        int currentLeft = 0;
+        int currentRight = -1;
+        int currentSum = 0;
+
+        // Process each query
+        for (Query query : queries) {
+            // Expand or shrink the current range to match query range
+
+            // Expand right boundary
+            while (currentRight < query.right) {
+                currentRight++;
+                currentSum += arr[currentRight];
+            }
+
+            // Shrink right boundary
+            while (currentRight > query.right) {
+                currentSum -= arr[currentRight];
+                currentRight--;
+            }
+
+            // Expand left boundary
+            while (currentLeft < query.left) {
+                currentSum -= arr[currentLeft];
+                currentLeft++;
+            }
+
+            // Shrink left boundary
+            while (currentLeft > query.left) {
+                currentLeft--;
+                currentSum += arr[currentLeft];
+            }
+
+            // Store the result
+            query.result = currentSum;
+        }
+
+        // Extract results in original query order
+        int[] results = new int[queries.length];
+        for (Query query : queries) {
+            results[query.index] = query.result;
+        }
+
+        return results;
+    }
+
+    /**
+     * Solves range frequency queries using Mo's Algorithm
+     * Example: Count occurrences of a specific value in range [L, R]
+     *
+     * @param arr the input array
+     * @param queries array of queries to process
+     * @param targetValue the value to count in each range
+     * @return array of results corresponding to each query
+     */
+    public static int[] solveRangeFrequencyQueries(int[] arr, Query[] queries, int targetValue) {
+        if (arr == null || queries == null || arr.length == 0) {
+            return new int[0];
+        }
+
+        int n = arr.length;
+        int blockSize = (int) Math.sqrt(n);
+
+        // Sort queries using Mo's ordering
+        Arrays.sort(queries, new MoComparator(blockSize));
+
+        // Initialize variables for current range
+        int currentLeft = 0;
+        int currentRight = -1;
+        int currentCount = 0;
+
+        // Process each query
+        for (Query query : queries) {
+            // Expand right boundary
+            while (currentRight < query.right) {
+                currentRight++;
+                if (arr[currentRight] == targetValue) {
+                    currentCount++;
+                }
+            }
+
+            // Shrink right boundary
+            while (currentRight > query.right) {
+                if (arr[currentRight] == targetValue) {
+                    currentCount--;
+                }
+                currentRight--;
+            }
+
+            // Expand left boundary
+            while (currentLeft < query.left) {
+                if (arr[currentLeft] == targetValue) {
+                    currentCount--;
+                }
+                currentLeft++;
+            }
+
+            // Shrink left boundary
+            while (currentLeft > query.left) {
+                currentLeft--;
+                if (arr[currentLeft] == targetValue) {
+                    currentCount++;
+                }
+            }
+
+            // Store the result
+            query.result = currentCount;
+        }
+
+        // Extract results in original query order
+        int[] results = new int[queries.length];
+        for (Query query : queries) {
+            results[query.index] = query.result;
+        }
+
+        return results;
+    }
+
+    /**
+     * Comparator for Mo's Algorithm query ordering
+     * Queries are sorted by block of left endpoint, then by right endpoint
+     */
+    private static class MoComparator implements Comparator<Query> {
+        private final int blockSize;
+
+        MoComparator(int blockSize) {
+            this.blockSize = blockSize;
+        }
+
+        @Override
+        public int compare(Query a, Query b) {
+            int blockA = a.left / blockSize;
+            int blockB = b.left / blockSize;
+
+            if (blockA != blockB) {
+                return Integer.compare(blockA, blockB);
+            }
+
+            // For odd blocks, sort right in ascending order
+            // For even blocks, sort right in descending order (optimization)
+            if ((blockA & 1) == 1) {
+                return Integer.compare(a.right, b.right);
+            } else {
+                return Integer.compare(b.right, a.right);
+            }
+        }
+    }
+
+    /**
+     * Demo method showing usage of Mo's Algorithm
+     *
+     * @param args command line arguments
+     */
+    public static void main(String[] args) {
+        // Example: Range sum queries
+        int[] arr = {1, 3, 5, 2, 7, 6, 3, 1, 4, 8};
+
+        Query[] queries = {
+            new Query(0, 2, 0), // Sum of elements from index 0 to 2: 1+3+5 = 9
+            new Query(1, 4, 1), // Sum of elements from index 1 to 4: 3+5+2+7 = 17
+            new Query(2, 6, 2), // Sum of elements from index 2 to 6: 5+2+7+6+3 = 23
+            new Query(3, 8, 3) // Sum of elements from index 3 to 8: 2+7+6+3+1+4 = 23
+        };
+
+        System.out.println("Array: " + Arrays.toString(arr));
+        System.out.println("Range Sum Queries:");
+
+        // Store original queries for display
+        Query[] originalQueries = new Query[queries.length];
+        for (int i = 0; i < queries.length; i++) {
+            originalQueries[i] = new Query(queries[i].left, queries[i].right, queries[i].index);
+        }
+
+        int[] results = solveRangeSumQueries(arr, queries);
+
+        for (int i = 0; i < originalQueries.length; i++) {
+            System.out.printf("Query %d: Sum of range [%d, %d] = %d%n", i, originalQueries[i].left, originalQueries[i].right, results[i]);
+        }
+
+        // Example: Range frequency queries
+        System.out.println("\nRange Frequency Queries (count of value 3):");
+        Query[] freqQueries = {
+            new Query(0, 5, 0), // Count of 3 in range [0, 5]: 1 occurrence
+            new Query(2, 8, 1), // Count of 3 in range [2, 8]: 2 occurrences
+            new Query(6, 9, 2) // Count of 3 in range [6, 9]: 1 occurrence
+        };
+
+        // Store original frequency queries for display
+        Query[] originalFreqQueries = new Query[freqQueries.length];
+        for (int i = 0; i < freqQueries.length; i++) {
+            originalFreqQueries[i] = new Query(freqQueries[i].left, freqQueries[i].right, freqQueries[i].index);
+        }
+
+        int[] freqResults = solveRangeFrequencyQueries(arr, freqQueries, 3);
+
+        for (int i = 0; i < originalFreqQueries.length; i++) {
+            System.out.printf("Query %d: Count of 3 in range [%d, %d] = %d%n", i, originalFreqQueries[i].left, originalFreqQueries[i].right, freqResults[i]);
+        }
+    }
+}
diff --git a/src/main/java/com/thealgorithms/recursion/DiceThrower.java b/src/main/java/com/thealgorithms/recursion/DiceThrower.java
new file mode 100644
index 000000000000..f46d82213aaa
--- /dev/null
+++ b/src/main/java/com/thealgorithms/recursion/DiceThrower.java
@@ -0,0 +1,113 @@
+package com.thealgorithms.recursion;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * DiceThrower - Generates all possible dice roll combinations that sum to a target
+ *
+ * This algorithm uses recursive backtracking to find all combinations of dice rolls
+ * (faces 1-6) that sum to a given target value.
+ *
+ * Example: If target = 4, possible combinations include:
+ * - "1111" (1+1+1+1 = 4)
+ * - "13" (1+3 = 4)
+ * - "22" (2+2 = 4)
+ * - "4" (4 = 4)
+ *
+ * @author BEASTSHRIRAM
+ * @see <a href="https://en.wikipedia.org/wiki/Backtracking">Backtracking Algorithm</a>
+ */
+public final class DiceThrower {
+
+    private DiceThrower() {
+        // Utility class
+    }
+
+    /**
+     * Returns all possible dice roll combinations that sum to the target
+     *
+     * @param target the target sum to achieve with dice rolls
+     * @return list of all possible combinations as strings
+     */
+    public static List<String> getDiceCombinations(int target) {
+        if (target < 0) {
+            throw new IllegalArgumentException("Target must be non-negative");
+        }
+        return generateCombinations("", target);
+    }
+
+    /**
+     * Prints all possible dice roll combinations that sum to the target
+     *
+     * @param target the target sum to achieve with dice rolls
+     */
+    public static void printDiceCombinations(int target) {
+        if (target < 0) {
+            throw new IllegalArgumentException("Target must be non-negative");
+        }
+        printCombinations("", target);
+    }
+
+    /**
+     * Recursive helper method to generate all combinations
+     *
+     * @param current the current combination being built
+     * @param remaining the remaining sum needed
+     * @return list of all combinations from this state
+     */
+    private static List<String> generateCombinations(String current, int remaining) {
+        List<String> combinations = new ArrayList<>();
+
+        // Base case: if remaining sum is 0, we found a valid combination
+        if (remaining == 0) {
+            combinations.add(current);
+            return combinations;
+        }
+
+        // Try all possible dice faces (1-6), but not more than remaining sum
+        for (int face = 1; face <= 6 && face <= remaining; face++) {
+            List<String> subCombinations = generateCombinations(current + face, remaining - face);
+            combinations.addAll(subCombinations);
+        }
+
+        return combinations;
+    }
+
+    /**
+     * Recursive helper method to print all combinations
+     *
+     * @param current the current combination being built
+     * @param remaining the remaining sum needed
+     */
+    private static void printCombinations(String current, int remaining) {
+        // Base case: if remaining sum is 0, we found a valid combination
+        if (remaining == 0) {
+            System.out.println(current);
+            return;
+        }
+
+        // Try all possible dice faces (1-6), but not more than remaining sum
+        for (int face = 1; face <= 6 && face <= remaining; face++) {
+            printCombinations(current + face, remaining - face);
+        }
+    }
+
+    /**
+     * Demo method to show usage
+     *
+     * @param args command line arguments
+     */
+    public static void main(String[] args) {
+        int target = 4;
+
+        System.out.println("All dice combinations that sum to " + target + ":");
+        List<String> combinations = getDiceCombinations(target);
+
+        for (String combination : combinations) {
+            System.out.println(combination);
+        }
+
+        System.out.println("\nTotal combinations: " + combinations.size());
+    }
+}
diff --git a/src/test/java/com/thealgorithms/others/MosAlgorithmTest.java b/src/test/java/com/thealgorithms/others/MosAlgorithmTest.java
new file mode 100644
index 000000000000..ac931eb0a2b9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/MosAlgorithmTest.java
@@ -0,0 +1,202 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for MosAlgorithm
+ *
+ * @author BEASTSHRIRAM
+ */
+class MosAlgorithmTest {
+
+    @Test
+    void testRangeSumQueriesBasic() {
+        int[] arr = {1, 3, 5, 2, 7};
+        MosAlgorithm.Query[] queries = {
+            new MosAlgorithm.Query(0, 2, 0), // Sum of [1, 3, 5] = 9
+            new MosAlgorithm.Query(1, 3, 1), // Sum of [3, 5, 2] = 10
+            new MosAlgorithm.Query(2, 4, 2) // Sum of [5, 2, 7] = 14
+        };
+
+        int[] expected = {9, 10, 14};
+        int[] results = MosAlgorithm.solveRangeSumQueries(arr, queries);
+
+        assertArrayEquals(expected, results);
+    }
+
+    @Test
+    void testRangeSumQueriesSingleElement() {
+        int[] arr = {5, 10, 15, 20};
+        MosAlgorithm.Query[] queries = {
+            new MosAlgorithm.Query(0, 0, 0), // Sum of [5] = 5
+            new MosAlgorithm.Query(1, 1, 1), // Sum of [10] = 10
+            new MosAlgorithm.Query(2, 2, 2), // Sum of [15] = 15
+            new MosAlgorithm.Query(3, 3, 3) // Sum of [20] = 20
+        };
+
+        int[] expected = {5, 10, 15, 20};
+        int[] results = MosAlgorithm.solveRangeSumQueries(arr, queries);
+
+        assertArrayEquals(expected, results);
+    }
+
+    @Test
+    void testRangeSumQueriesFullArray() {
+        int[] arr = {1, 2, 3, 4, 5};
+        MosAlgorithm.Query[] queries = {
+            new MosAlgorithm.Query(0, 4, 0) // Sum of entire array = 15
+        };
+
+        int[] expected = {15};
+        int[] results = MosAlgorithm.solveRangeSumQueries(arr, queries);
+
+        assertArrayEquals(expected, results);
+    }
+
+    @Test
+    void testRangeSumQueriesOverlapping() {
+        int[] arr = {2, 4, 6, 8, 10};
+        MosAlgorithm.Query[] queries = {
+            new MosAlgorithm.Query(0, 2, 0), // Sum of [2, 4, 6] = 12
+            new MosAlgorithm.Query(1, 3, 1), // Sum of [4, 6, 8] = 18
+            new MosAlgorithm.Query(2, 4, 2) // Sum of [6, 8, 10] = 24
+        };
+
+        int[] expected = {12, 18, 24};
+        int[] results = MosAlgorithm.solveRangeSumQueries(arr, queries);
+
+        assertArrayEquals(expected, results);
+    }
+
+    @Test
+    void testRangeFrequencyQueriesBasic() {
+        int[] arr = {1, 2, 2, 1, 3, 2, 1};
+        MosAlgorithm.Query[] queries = {
+            new MosAlgorithm.Query(0, 3, 0), // Count of 2 in [1, 2, 2, 1] = 2
+            new MosAlgorithm.Query(1, 5, 1), // Count of 2 in [2, 2, 1, 3, 2] = 3
+            new MosAlgorithm.Query(4, 6, 2) // Count of 2 in [3, 2, 1] = 1
+        };
+
+        int[] expected = {2, 3, 1};
+        int[] results = MosAlgorithm.solveRangeFrequencyQueries(arr, queries, 2);
+
+        assertArrayEquals(expected, results);
+    }
+
+    @Test
+    void testRangeFrequencyQueriesNoMatch() {
+        int[] arr = {1, 3, 5, 7, 9};
+        MosAlgorithm.Query[] queries = {
+            new MosAlgorithm.Query(0, 2, 0), // Count of 2 in [1, 3, 5] = 0
+            new MosAlgorithm.Query(1, 4, 1) // Count of 2 in [3, 5, 7, 9] = 0
+        };
+
+        int[] expected = {0, 0};
+        int[] results = MosAlgorithm.solveRangeFrequencyQueries(arr, queries, 2);
+
+        assertArrayEquals(expected, results);
+    }
+
+    @Test
+    void testRangeFrequencyQueriesAllMatch() {
+        int[] arr = {5, 5, 5, 5, 5};
+        MosAlgorithm.Query[] queries = {
+            new MosAlgorithm.Query(0, 2, 0), // Count of 5 in [5, 5, 5] = 3
+            new MosAlgorithm.Query(1, 3, 1), // Count of 5 in [5, 5, 5] = 3
+            new MosAlgorithm.Query(0, 4, 2) // Count of 5 in [5, 5, 5, 5, 5] = 5
+        };
+
+        int[] expected = {3, 3, 5};
+        int[] results = MosAlgorithm.solveRangeFrequencyQueries(arr, queries, 5);
+
+        assertArrayEquals(expected, results);
+    }
+
+    @Test
+    void testEmptyArray() {
+        int[] arr = {};
+        MosAlgorithm.Query[] queries = {};
+
+        int[] expected = {};
+        int[] results = MosAlgorithm.solveRangeSumQueries(arr, queries);
+
+        assertArrayEquals(expected, results);
+    }
+
+    @Test
+    void testNullInputs() {
+        int[] results1 = MosAlgorithm.solveRangeSumQueries(null, null);
+        assertArrayEquals(new int[0], results1);
+
+        int[] results2 = MosAlgorithm.solveRangeFrequencyQueries(null, null, 1);
+        assertArrayEquals(new int[0], results2);
+    }
+
+    @Test
+    void testQueryStructure() {
+        MosAlgorithm.Query query = new MosAlgorithm.Query(1, 5, 0);
+
+        assertEquals(1, query.left);
+        assertEquals(5, query.right);
+        assertEquals(0, query.index);
+        assertEquals(0, query.result); // Default value
+    }
+
+    @Test
+    void testLargerArray() {
+        int[] arr = {1, 4, 2, 8, 5, 7, 3, 6, 9, 10};
+        MosAlgorithm.Query[] queries = {
+            new MosAlgorithm.Query(0, 4, 0), // Sum of [1, 4, 2, 8, 5] = 20
+            new MosAlgorithm.Query(2, 7, 1), // Sum of [2, 8, 5, 7, 3, 6] = 31
+            new MosAlgorithm.Query(5, 9, 2), // Sum of [7, 3, 6, 9, 10] = 35
+            new MosAlgorithm.Query(1, 8, 3) // Sum of [4, 2, 8, 5, 7, 3, 6, 9] = 44
+        };
+
+        int[] expected = {20, 31, 35, 44};
+        int[] results = MosAlgorithm.solveRangeSumQueries(arr, queries);
+
+        assertArrayEquals(expected, results);
+    }
+
+    @Test
+    void testRangeFrequencyWithDuplicates() {
+        int[] arr = {3, 1, 4, 1, 5, 9, 2, 6, 5, 3};
+        MosAlgorithm.Query[] queries = {
+            new MosAlgorithm.Query(0, 5, 0), // Count of 1 in [3, 1, 4, 1, 5, 9] = 2
+            new MosAlgorithm.Query(3, 9, 1), // Count of 1 in [1, 5, 9, 2, 6, 5, 3] = 1
+            new MosAlgorithm.Query(0, 9, 2) // Count of 1 in entire array = 2
+        };
+
+        int[] expected = {2, 1, 2};
+        int[] results = MosAlgorithm.solveRangeFrequencyQueries(arr, queries, 1);
+
+        assertArrayEquals(expected, results);
+    }
+
+    @Test
+    void testMainMethod() {
+        // Capture System.out
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        PrintStream originalOut = System.out;
+        System.setOut(new PrintStream(outputStream));
+
+        try {
+            // Test main method
+            MosAlgorithm.main(new String[] {});
+            String output = outputStream.toString();
+
+            // Verify expected output contains demonstration
+            assertTrue(output.contains("Range Sum Queries:"));
+            assertTrue(output.contains("Range Frequency Queries (count of value 3):"));
+            assertTrue(output.contains("Array: [1, 3, 5, 2, 7, 6, 3, 1, 4, 8]"));
+        } finally {
+            System.setOut(originalOut);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/recursion/DiceThrowerTest.java b/src/test/java/com/thealgorithms/recursion/DiceThrowerTest.java
new file mode 100644
index 000000000000..0804e9bfff25
--- /dev/null
+++ b/src/test/java/com/thealgorithms/recursion/DiceThrowerTest.java
@@ -0,0 +1,223 @@
+package com.thealgorithms.recursion;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for DiceThrower
+ *
+ * @author BEASTSHRIRAM
+ */
+class DiceThrowerTest {
+
+    @Test
+    void testTargetZero() {
+        List<String> result = DiceThrower.getDiceCombinations(0);
+        assertEquals(1, result.size());
+        assertEquals("", result.get(0));
+    }
+
+    @Test
+    void testTargetOne() {
+        List<String> result = DiceThrower.getDiceCombinations(1);
+        assertEquals(1, result.size());
+        assertEquals("1", result.get(0));
+    }
+
+    @Test
+    void testTargetTwo() {
+        List<String> result = DiceThrower.getDiceCombinations(2);
+        assertEquals(2, result.size());
+        assertTrue(result.contains("11"));
+        assertTrue(result.contains("2"));
+    }
+
+    @Test
+    void testTargetThree() {
+        List<String> result = DiceThrower.getDiceCombinations(3);
+        assertEquals(4, result.size());
+        assertTrue(result.contains("111"));
+        assertTrue(result.contains("12"));
+        assertTrue(result.contains("21"));
+        assertTrue(result.contains("3"));
+    }
+
+    @Test
+    void testTargetFour() {
+        List<String> result = DiceThrower.getDiceCombinations(4);
+        assertEquals(8, result.size());
+        assertTrue(result.contains("1111"));
+        assertTrue(result.contains("112"));
+        assertTrue(result.contains("121"));
+        assertTrue(result.contains("13"));
+        assertTrue(result.contains("211"));
+        assertTrue(result.contains("22"));
+        assertTrue(result.contains("31"));
+        assertTrue(result.contains("4"));
+    }
+
+    @Test
+    void testTargetSix() {
+        List<String> result = DiceThrower.getDiceCombinations(6);
+        assertEquals(32, result.size());
+        assertTrue(result.contains("6"));
+        assertTrue(result.contains("33"));
+        assertTrue(result.contains("222"));
+        assertTrue(result.contains("111111"));
+    }
+
+    @Test
+    void testTargetSeven() {
+        List<String> result = DiceThrower.getDiceCombinations(7);
+        // Should include combinations like 61, 52, 43, 331, 322, 2221, etc.
+        assertTrue(result.size() > 0);
+        assertTrue(result.contains("61"));
+        assertTrue(result.contains("16"));
+        assertTrue(result.contains("52"));
+        assertTrue(result.contains("43"));
+    }
+
+    @Test
+    void testLargerTarget() {
+        List<String> result = DiceThrower.getDiceCombinations(10);
+        assertTrue(result.size() > 0);
+        // All results should sum to 10
+        for (String combination : result) {
+            int sum = 0;
+            for (char c : combination.toCharArray()) {
+                sum += Character.getNumericValue(c);
+            }
+            assertEquals(10, sum);
+        }
+    }
+
+    @Test
+    void testNegativeTarget() {
+        assertThrows(IllegalArgumentException.class, () -> { DiceThrower.getDiceCombinations(-1); });
+    }
+
+    @Test
+    void testNegativeTargetPrint() {
+        assertThrows(IllegalArgumentException.class, () -> { DiceThrower.printDiceCombinations(-1); });
+    }
+
+    @Test
+    void testAllCombinationsValid() {
+        List<String> result = DiceThrower.getDiceCombinations(5);
+
+        for (String combination : result) {
+            // Check that each character is a valid dice face (1-6)
+            for (char c : combination.toCharArray()) {
+                int face = Character.getNumericValue(c);
+                assertTrue(face >= 1 && face <= 6, "Invalid dice face: " + face);
+            }
+
+            // Check that the sum equals the target
+            int sum = 0;
+            for (char c : combination.toCharArray()) {
+                sum += Character.getNumericValue(c);
+            }
+            assertEquals(5, sum, "Combination " + combination + " does not sum to 5");
+        }
+    }
+
+    @Test
+    void testPrintDiceCombinations() {
+        // Capture System.out
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        PrintStream originalOut = System.out;
+        System.setOut(new PrintStream(outputStream));
+
+        try {
+            // Test printing combinations for target 3
+            DiceThrower.printDiceCombinations(3);
+            String output = outputStream.toString();
+
+            // Verify all expected combinations are printed
+            assertTrue(output.contains("111"));
+            assertTrue(output.contains("12"));
+            assertTrue(output.contains("21"));
+            assertTrue(output.contains("3"));
+
+            // Count number of lines (combinations)
+            String[] lines = output.trim().split("\n");
+            assertEquals(4, lines.length);
+        } finally {
+            // Restore System.out
+            System.setOut(originalOut);
+        }
+    }
+
+    @Test
+    void testPrintDiceCombinationsZero() {
+        // Capture System.out
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        PrintStream originalOut = System.out;
+        System.setOut(new PrintStream(outputStream));
+
+        try {
+            DiceThrower.printDiceCombinations(0);
+            String output = outputStream.toString();
+
+            // Should print empty string (one line)
+            assertEquals("", output.trim());
+        } finally {
+            System.setOut(originalOut);
+        }
+    }
+
+    @Test
+    void testMainMethod() {
+        // Capture System.out
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        PrintStream originalOut = System.out;
+        System.setOut(new PrintStream(outputStream));
+
+        try {
+            // Test main method
+            DiceThrower.main(new String[] {});
+            String output = outputStream.toString();
+
+            // Verify expected output contains header and combinations
+            assertTrue(output.contains("All dice combinations that sum to 4:"));
+            assertTrue(output.contains("Total combinations: 8"));
+            assertTrue(output.contains("1111"));
+            assertTrue(output.contains("22"));
+            assertTrue(output.contains("4"));
+        } finally {
+            System.setOut(originalOut);
+        }
+    }
+
+    @Test
+    void testEdgeCaseTargetFive() {
+        List<String> result = DiceThrower.getDiceCombinations(5);
+        assertEquals(16, result.size());
+
+        // Test specific combinations exist
+        assertTrue(result.contains("11111"));
+        assertTrue(result.contains("1112"));
+        assertTrue(result.contains("122"));
+        assertTrue(result.contains("14"));
+        assertTrue(result.contains("23"));
+        assertTrue(result.contains("5"));
+    }
+
+    @Test
+    void testTargetGreaterThanSix() {
+        List<String> result = DiceThrower.getDiceCombinations(8);
+        assertTrue(result.size() > 0);
+
+        // Verify some expected combinations
+        assertTrue(result.contains("62"));
+        assertTrue(result.contains("53"));
+        assertTrue(result.contains("44"));
+        assertTrue(result.contains("2222"));
+    }
+}

From 5f8d8eeb7b01e3e7e245c160fadbf376790001d7 Mon Sep 17 00:00:00 2001
From: "Udaya Krishnan.M" <101326005+UdayaKrishnanM@users.noreply.github.com>
Date: Wed, 8 Oct 2025 17:25:38 +0530
Subject: [PATCH 0987/1338] Added Pretty Display method and
 BSTRecursiveGenericTests.java (#6621)

* added binarysearchtree

* added binarysearchtree

* updated

* updated the test values

* updated build issues

* updated

* updated

* updated

* updated

* updated

* updated

* updated

* added pretty display method

* added pretty display method

* updated pretty Display and added BSTRecursiveGenericTest.java

* updated pretty Display and added BSTRecursiveGenericTest.java

* updated pretty Display and added BSTRecursiveGenericTest.java

* updated pretty Display and added BSTRecursiveGenericTest.java

* updated pretty Display and added BSTRecursiveGenericTest.java

* added pretty display method

* updated pretty Display and added BSTRecursiveGenericTest.java

* updated pretty Display and added BSTRecursiveGenericTest.java

* updated pretty Display and added BSTRecursiveGenericTest.java

---------

Co-authored-by: Krishnan M <2318467@cognizant.com>
Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../trees/BSTRecursiveGeneric.java            |  44 ++++-
 .../trees/BSTRecursiveGenericTest.java        | 169 ++++++++++++++++++
 2 files changed, 210 insertions(+), 3 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveGenericTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java b/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java
index 5c1334ffa0e8..0245372fe012 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java
@@ -13,6 +13,7 @@
  * </p>
  *
  * @author [Madhur Panwar](<a href="https://github.com/mdrpanwar">git-Madhur Panwar</a>)
+ * @author [Udaya Krishnan M](<a href="https://github.com/UdayaKrishnanM/">git-Udaya Krishnan M</a>) {added prettyDisplay() method}
  */
 public class BSTRecursiveGeneric<T extends Comparable<T>> {
 
@@ -28,6 +29,29 @@ public BSTRecursiveGeneric() {
         root = null;
     }
 
+    /**
+     * Displays the tree is a structed format
+     */
+    public void prettyDisplay() {
+        prettyDisplay(root, 0);
+    }
+
+    private void prettyDisplay(Node<T> node, int level) {
+        if (node == null) {
+            return;
+        }
+        prettyDisplay(node.right, level + 1);
+        if (level != 0) {
+            for (int i = 0; i < level - 1; i++) {
+                System.out.print("|\t");
+            }
+            System.out.println("|---->" + node.data);
+        } else {
+            System.out.println(node.data);
+        }
+        prettyDisplay(node.left, level + 1);
+    }
+
     /**
      * main function for testing
      */
@@ -38,7 +62,12 @@ public static void main(String[] args) {
 
         integerTree.add(5);
         integerTree.add(10);
-        integerTree.add(9);
+        integerTree.add(-9);
+        integerTree.add(4);
+        integerTree.add(3);
+        integerTree.add(1);
+        System.out.println("Pretty Display of current tree is:");
+        integerTree.prettyDisplay();
         assert !integerTree.find(4)
             : "4 is not yet present in BST";
         assert integerTree.find(10)
@@ -54,16 +83,21 @@ public static void main(String[] args) {
         assert integerTree.find(70)
             : "70 was inserted but not found";
         /*
-     Will print in following order
-     5 10 20 70
+            Will print in following order
+            5 10 20 70
          */
+        System.out.println("Pretty Display of current tree is:");
+        integerTree.prettyDisplay();
         integerTree.inorder();
+        System.out.println("Pretty Display of current tree is:");
+        integerTree.prettyDisplay();
         System.out.println();
         System.out.println("Testing for string data...");
         // String
         BSTRecursiveGeneric<String> stringTree = new BSTRecursiveGeneric<String>();
 
         stringTree.add("banana");
+        stringTree.add("apple");
         stringTree.add("pineapple");
         stringTree.add("date");
         assert !stringTree.find("girl")
@@ -80,11 +114,15 @@ public static void main(String[] args) {
         stringTree.add("hills");
         assert stringTree.find("hills")
             : "hills was inserted but not found";
+        System.out.println("Pretty Display of current tree is:");
+        stringTree.prettyDisplay();
         /*
      Will print in following order
      banana hills india pineapple
          */
         stringTree.inorder();
+        System.out.println("Pretty Display of current tree is:");
+        stringTree.prettyDisplay();
     }
 
     /**
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveGenericTest.java b/src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveGenericTest.java
new file mode 100644
index 000000000000..5ec0080c5fb8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveGenericTest.java
@@ -0,0 +1,169 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for BSTRecursiveGeneric class.
+ * Covers insertion, deletion, search, traversal, sorting, and display.
+ *
+ * Author: Udaya Krishnan M
+ * GitHub: https://github.com/UdayaKrishnanM/
+ */
+class BSTRecursiveGenericTest {
+
+    private BSTRecursiveGeneric<Integer> intTree;
+    private BSTRecursiveGeneric<String> stringTree;
+
+    /**
+     * Initializes test trees before each test.
+     */
+    @BeforeEach
+    void setUp() {
+        intTree = new BSTRecursiveGeneric<>();
+        stringTree = new BSTRecursiveGeneric<>();
+    }
+
+    /**
+     * Tests insertion and search of integer values.
+     */
+    @Test
+    void testAddAndFindInteger() {
+        intTree.add(10);
+        intTree.add(5);
+        intTree.add(15);
+        assertTrue(intTree.find(10));
+        assertTrue(intTree.find(5));
+        assertTrue(intTree.find(15));
+        assertFalse(intTree.find(20));
+    }
+
+    /**
+     * Tests insertion and search of string values.
+     */
+    @Test
+    void testAddAndFindString() {
+        stringTree.add("apple");
+        stringTree.add("banana");
+        stringTree.add("cherry");
+        assertTrue(stringTree.find("banana"));
+        assertFalse(stringTree.find("date"));
+    }
+
+    /**
+     * Tests deletion of existing and non-existing elements.
+     */
+    @Test
+    void testRemoveElements() {
+        intTree.add(10);
+        intTree.add(5);
+        intTree.add(15);
+        assertTrue(intTree.find(5));
+        intTree.remove(5);
+        assertFalse(intTree.find(5));
+        intTree.remove(100); // non-existent
+        assertFalse(intTree.find(100));
+    }
+
+    /**
+     * Tests inorder traversal output.
+     */
+    @Test
+    void testInorderTraversal() {
+        intTree.add(20);
+        intTree.add(10);
+        intTree.add(30);
+        intTree.inorder(); // visually verify output
+        assertTrue(true);
+    }
+
+    /**
+     * Tests preorder traversal output.
+     */
+    @Test
+    void testPreorderTraversal() {
+        intTree.add(20);
+        intTree.add(10);
+        intTree.add(30);
+        intTree.preorder(); // visually verify output
+        assertTrue(true);
+    }
+
+    /**
+     * Tests postorder traversal output.
+     */
+    @Test
+    void testPostorderTraversal() {
+        intTree.add(20);
+        intTree.add(10);
+        intTree.add(30);
+        intTree.postorder(); // visually verify output
+        assertTrue(true);
+    }
+
+    /**
+     * Tests inorderSort returns sorted list.
+     */
+    @Test
+    void testInorderSort() {
+        intTree.add(30);
+        intTree.add(10);
+        intTree.add(20);
+        List<Integer> sorted = intTree.inorderSort();
+        assertEquals(List.of(10, 20, 30), sorted);
+    }
+
+    /**
+     * Tests prettyDisplay method for visual tree structure.
+     */
+    @Test
+    void testPrettyDisplay() {
+        intTree.add(50);
+        intTree.add(30);
+        intTree.add(70);
+        intTree.add(20);
+        intTree.add(40);
+        intTree.add(60);
+        intTree.add(80);
+        intTree.prettyDisplay(); // visually verify output
+        assertTrue(true);
+    }
+
+    /**
+     * Tests edge case: empty tree.
+     */
+    @Test
+    void testEmptyTree() {
+        assertFalse(intTree.find(1));
+        List<Integer> sorted = intTree.inorderSort();
+        assertTrue(sorted.isEmpty());
+    }
+
+    /**
+     * Tests edge case: single node tree.
+     */
+    @Test
+    void testSingleNodeTree() {
+        intTree.add(42);
+        assertTrue(intTree.find(42));
+        intTree.remove(42);
+        assertFalse(intTree.find(42));
+    }
+
+    /**
+     * Tests duplicate insertions.
+     */
+    @Test
+    void testDuplicateInsertions() {
+        intTree.add(10);
+        intTree.add(10);
+        intTree.add(10);
+        List<Integer> sorted = intTree.inorderSort();
+        assertEquals(List.of(10), sorted); // assuming duplicates are ignored
+    }
+}

From b031a0bbbac28a4ce2af6ddbd1efe00b0188fe2f Mon Sep 17 00:00:00 2001
From: Yash Rajput <52812070+the-yash-rajput@users.noreply.github.com>
Date: Wed, 8 Oct 2025 17:46:14 +0530
Subject: [PATCH 0988/1338] Adding PiApproximation algo (#6602)

* Adding PiApproximation algo

* Added clang formatting

* Added private method

* checkstyle fix

* checkstyle fix

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../thealgorithms/maths/PiApproximation.java  |  74 ++++++++
 .../maths/PiApproximationTest.java            | 169 ++++++++++++++++++
 2 files changed, 243 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/PiApproximation.java
 create mode 100644 src/test/java/com/thealgorithms/maths/PiApproximationTest.java

diff --git a/src/main/java/com/thealgorithms/maths/PiApproximation.java b/src/main/java/com/thealgorithms/maths/PiApproximation.java
new file mode 100644
index 000000000000..1be945d7ef24
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/PiApproximation.java
@@ -0,0 +1,74 @@
+package com.thealgorithms.maths;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+/**
+ * Implementation to calculate an estimate of the number π (Pi).
+ *
+ * We take a random point P with coordinates (x, y) such that 0 ≤ x ≤ 1 and 0 ≤ y ≤ 1.
+ * If x² + y² ≤ 1, then the point is inside the quarter disk of radius 1,
+ * else the point is outside. We know that the probability of the point being
+ * inside the quarter disk is equal to π/4.
+ *
+ *
+ * @author [Yash Rajput](https://github.com/the-yash-rajput)
+ */
+public final class PiApproximation {
+
+    private PiApproximation() {
+        throw new AssertionError("No instances.");
+    }
+
+    /**
+     * Structure representing a point with coordinates (x, y)
+     * where 0 ≤ x ≤ 1 and 0 ≤ y ≤ 1.
+     */
+    static class Point {
+        double x;
+        double y;
+
+        Point(double x, double y) {
+            this.x = x;
+            this.y = y;
+        }
+    }
+
+    /**
+     * This function uses the points in a given list (drawn at random)
+     * to return an approximation of the number π.
+     *
+     * @param pts List of points where each point contains x and y coordinates
+     * @return An estimate of the number π
+     */
+    public static double approximatePi(List<Point> pts) {
+        double count = 0; // Points in circle
+
+        for (Point p : pts) {
+            if ((p.x * p.x) + (p.y * p.y) <= 1) {
+                count++;
+            }
+        }
+
+        return 4.0 * count / pts.size();
+    }
+
+    /**
+     * Generates random points for testing the Pi approximation.
+     *
+     * @param numPoints Number of random points to generate
+     * @return List of random points
+     */
+    public static List<Point> generateRandomPoints(int numPoints) {
+        List<Point> points = new ArrayList<>();
+        Random rand = new Random();
+
+        for (int i = 0; i < numPoints; i++) {
+            double x = rand.nextDouble(); // Random value between 0 and 1
+            double y = rand.nextDouble(); // Random value between 0 and 1
+            points.add(new Point(x, y));
+        }
+
+        return points;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/PiApproximationTest.java b/src/test/java/com/thealgorithms/maths/PiApproximationTest.java
new file mode 100644
index 000000000000..47da3b46a336
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/PiApproximationTest.java
@@ -0,0 +1,169 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class PiApproximationTest {
+
+    private static final double DELTA = 0.5; // Tolerance for Pi approximation
+    private static final double TIGHT_DELTA = 0.1; // Tighter tolerance for large samples
+
+    /**
+     * Test with known points that are all inside the quarter circle.
+     */
+    @Test
+    public void testAllPointsInside() {
+        List<PiApproximation.Point> points = new ArrayList<>();
+        points.add(new PiApproximation.Point(0.0, 0.0)); // Origin
+        points.add(new PiApproximation.Point(0.5, 0.5)); // Inside
+        points.add(new PiApproximation.Point(0.3, 0.3)); // Inside
+
+        double result = PiApproximation.approximatePi(points);
+        // All points inside, so result should be 4.0
+        assertEquals(4.0, result, 0.001);
+    }
+
+    /**
+     * Test with known points that are all outside the quarter circle.
+     */
+    @Test
+    public void testAllPointsOutside() {
+        List<PiApproximation.Point> points = new ArrayList<>();
+        points.add(new PiApproximation.Point(1.0, 1.0)); // Corner - outside
+        points.add(new PiApproximation.Point(0.9, 0.9)); // Outside
+
+        double result = PiApproximation.approximatePi(points);
+        // No points inside, so result should be 0.0
+        assertEquals(0.0, result, 0.001);
+    }
+
+    /**
+     * Test with mixed points (some inside, some outside).
+     */
+    @Test
+    public void testMixedPoints() {
+        List<PiApproximation.Point> points = new ArrayList<>();
+        // Inside points
+        points.add(new PiApproximation.Point(0.0, 0.0));
+        points.add(new PiApproximation.Point(0.5, 0.5));
+        // Outside points
+        points.add(new PiApproximation.Point(1.0, 1.0));
+        points.add(new PiApproximation.Point(0.9, 0.9));
+
+        double result = PiApproximation.approximatePi(points);
+        // 2 out of 4 points inside: 4 * 2/4 = 2.0
+        assertEquals(2.0, result, 0.001);
+    }
+
+    /**
+     * Test with boundary point (on the circle).
+     */
+    @Test
+    public void testBoundaryPoint() {
+        List<PiApproximation.Point> points = new ArrayList<>();
+        points.add(new PiApproximation.Point(1.0, 0.0)); // On circle: x² + y² = 1
+        points.add(new PiApproximation.Point(0.0, 1.0)); // On circle
+
+        double result = PiApproximation.approximatePi(points);
+        // Boundary points should be counted as inside (≤ 1)
+        assertEquals(4.0, result, 0.001);
+    }
+
+    /**
+     * Test with small random sample (moderate accuracy expected).
+     */
+    @Test
+    public void testSmallRandomSample() {
+        List<PiApproximation.Point> points = PiApproximation.generateRandomPoints(1000);
+        double result = PiApproximation.approximatePi(points);
+
+        // With 1000 points, result should be reasonably close to π
+        assertEquals(Math.PI, result, DELTA);
+    }
+
+    /**
+     * Test with large random sample (better accuracy expected).
+     */
+    @Test
+    public void testLargeRandomSample() {
+        List<PiApproximation.Point> points = PiApproximation.generateRandomPoints(100000);
+        double result = PiApproximation.approximatePi(points);
+
+        // With 100000 points, result should be very close to π
+        assertEquals(Math.PI, result, TIGHT_DELTA);
+    }
+
+    /**
+     * Test that result is always positive.
+     */
+    @Test
+    public void testResultIsPositive() {
+        List<PiApproximation.Point> points = PiApproximation.generateRandomPoints(1000);
+        double result = PiApproximation.approximatePi(points);
+
+        assertTrue(result >= 0, "Pi approximation should be positive");
+    }
+
+    /**
+     * Test that result is bounded (0 ≤ result ≤ 4).
+     */
+    @Test
+    public void testResultIsBounded() {
+        List<PiApproximation.Point> points = PiApproximation.generateRandomPoints(1000);
+        double result = PiApproximation.approximatePi(points);
+
+        assertTrue(result >= 0 && result <= 4, "Pi approximation should be between 0 and 4");
+    }
+
+    /**
+     * Test with single point inside.
+     */
+    @Test
+    public void testSinglePointInside() {
+        List<PiApproximation.Point> points = new ArrayList<>();
+        points.add(new PiApproximation.Point(0.0, 0.0));
+
+        double result = PiApproximation.approximatePi(points);
+        assertEquals(4.0, result, 0.001);
+    }
+
+    /**
+     * Test with single point outside.
+     */
+    @Test
+    public void testSinglePointOutside() {
+        List<PiApproximation.Point> points = new ArrayList<>();
+        points.add(new PiApproximation.Point(1.0, 1.0));
+
+        double result = PiApproximation.approximatePi(points);
+        assertEquals(0.0, result, 0.001);
+    }
+
+    /**
+     * Test that generated points are within valid range [0, 1].
+     */
+    @Test
+    public void testGeneratedPointsInRange() {
+        List<PiApproximation.Point> points = PiApproximation.generateRandomPoints(100);
+
+        for (PiApproximation.Point p : points) {
+            assertTrue(p.x >= 0 && p.x <= 1, "X coordinate should be between 0 and 1");
+            assertTrue(p.y >= 0 && p.y <= 1, "Y coordinate should be between 0 and 1");
+        }
+    }
+
+    /**
+     * Test that the correct number of points are generated.
+     */
+    @Test
+    public void testCorrectNumberOfPointsGenerated() {
+        int expectedSize = 500;
+        List<PiApproximation.Point> points = PiApproximation.generateRandomPoints(expectedSize);
+
+        assertEquals(expectedSize, points.size());
+    }
+}

From 50b1bcdc6776477b0e616ec1972997c5be4f08ae Mon Sep 17 00:00:00 2001
From: Saahil Mahato <mahatosaahil4@gmail.com>
Date: Wed, 8 Oct 2025 21:54:18 +0545
Subject: [PATCH 0989/1338] feat: add damerau-levenshtein distance algorithm
 (#6706)

* feat: add damerau-levenshtein distance algorithm

* refactor: remove useless parentheses

* refactor: add class link to test
---
 .../DamerauLevenshteinDistance.java           | 185 +++++++++++++++++
 .../DamerauLevenshteinDistanceTest.java       | 194 ++++++++++++++++++
 2 files changed, 379 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistance.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistanceTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistance.java b/src/main/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistance.java
new file mode 100644
index 000000000000..9721d4ab0ad5
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistance.java
@@ -0,0 +1,185 @@
+package com.thealgorithms.dynamicprogramming;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Implementation of the full Damerau–Levenshtein distance algorithm.
+ *
+ * This algorithm calculates the minimum number of operations required
+ * to transform one string into another. Supported operations are:
+ * insertion, deletion, substitution, and transposition of adjacent characters.
+ *
+ * Unlike the restricted version (OSA), this implementation allows multiple
+ * edits on the same substring, computing the true edit distance.
+ *
+ * Time Complexity: O(n * m * max(n, m))
+ * Space Complexity: O(n * m)
+ */
+public final class DamerauLevenshteinDistance {
+
+    private DamerauLevenshteinDistance() {
+        // Utility class
+    }
+
+    /**
+     * Computes the full Damerau–Levenshtein distance between two strings.
+     *
+     * @param s1 the first string
+     * @param s2 the second string
+     * @return the minimum edit distance between the two strings
+     * @throws IllegalArgumentException if either input string is null
+     */
+    public static int distance(String s1, String s2) {
+        validateInputs(s1, s2);
+
+        int n = s1.length();
+        int m = s2.length();
+
+        Map<Character, Integer> charLastPosition = buildCharacterMap(s1, s2);
+        int[][] dp = initializeTable(n, m);
+
+        fillTable(s1, s2, dp, charLastPosition);
+
+        return dp[n + 1][m + 1];
+    }
+
+    /**
+     * Validates that both input strings are not null.
+     *
+     * @param s1 the first string to validate
+     * @param s2 the second string to validate
+     * @throws IllegalArgumentException if either string is null
+     */
+    private static void validateInputs(String s1, String s2) {
+        if (s1 == null || s2 == null) {
+            throw new IllegalArgumentException("Input strings must not be null.");
+        }
+    }
+
+    /**
+     * Builds a character map containing all unique characters from both strings.
+     * Each character is initialized with a position value of 0.
+     *
+     * This map is used to track the last occurrence position of each character
+     * during the distance computation, which is essential for handling transpositions.
+     *
+     * @param s1 the first string
+     * @param s2 the second string
+     * @return a map containing all unique characters from both strings, initialized to 0
+     */
+    private static Map<Character, Integer> buildCharacterMap(String s1, String s2) {
+        Map<Character, Integer> charMap = new HashMap<>();
+        for (char c : s1.toCharArray()) {
+            charMap.putIfAbsent(c, 0);
+        }
+        for (char c : s2.toCharArray()) {
+            charMap.putIfAbsent(c, 0);
+        }
+        return charMap;
+    }
+
+    /**
+     * Initializes the dynamic programming table for the algorithm.
+     *
+     * The table has dimensions (n+2) x (m+2) where n and m are the lengths
+     * of the input strings. The extra rows and columns are used to handle
+     * the transposition operation correctly.
+     *
+     * The first row and column are initialized with the maximum possible distance,
+     * while the second row and column represent the base case of transforming
+     * from an empty string.
+     *
+     * @param n the length of the first string
+     * @param m the length of the second string
+     * @return an initialized DP table ready for computation
+     */
+    private static int[][] initializeTable(int n, int m) {
+        int maxDist = n + m;
+        int[][] dp = new int[n + 2][m + 2];
+
+        dp[0][0] = maxDist;
+
+        for (int i = 0; i <= n; i++) {
+            dp[i + 1][0] = maxDist;
+            dp[i + 1][1] = i;
+        }
+
+        for (int j = 0; j <= m; j++) {
+            dp[0][j + 1] = maxDist;
+            dp[1][j + 1] = j;
+        }
+
+        return dp;
+    }
+
+    /**
+     * Fills the dynamic programming table by computing the minimum edit distance
+     * for each substring pair.
+     *
+     * This method implements the core algorithm logic, iterating through both strings
+     * and computing the minimum cost of transforming substrings. It considers all
+     * four operations: insertion, deletion, substitution, and transposition.
+     *
+     * The character position map is updated as we progress through the first string
+     * to enable efficient transposition cost calculation.
+     *
+     * @param s1 the first string
+     * @param s2 the second string
+     * @param dp the dynamic programming table to fill
+     * @param charLastPosition map tracking the last position of each character in s1
+     */
+    private static void fillTable(String s1, String s2, int[][] dp, Map<Character, Integer> charLastPosition) {
+        int n = s1.length();
+        int m = s2.length();
+
+        for (int i = 1; i <= n; i++) {
+            int lastMatchCol = 0;
+
+            for (int j = 1; j <= m; j++) {
+                char char1 = s1.charAt(i - 1);
+                char char2 = s2.charAt(j - 1);
+
+                int lastMatchRow = charLastPosition.get(char2);
+                int cost = (char1 == char2) ? 0 : 1;
+
+                if (char1 == char2) {
+                    lastMatchCol = j;
+                }
+
+                dp[i + 1][j + 1] = computeMinimumCost(dp, i, j, lastMatchRow, lastMatchCol, cost);
+            }
+
+            charLastPosition.put(s1.charAt(i - 1), i);
+        }
+    }
+
+    /**
+     * Computes the minimum cost among all possible operations at the current position.
+     *
+     * This method evaluates four possible operations:
+     * 1. Substitution: replace character at position i with character at position j
+     * 2. Insertion: insert character from s2 at position j
+     * 3. Deletion: delete character from s1 at position i
+     * 4. Transposition: swap characters that have been seen before
+     *
+     * The transposition cost accounts for the gap between the current position
+     * and the last position where matching characters were found.
+     *
+     * @param dp the dynamic programming table
+     * @param i the current position in the first string (1-indexed in the DP table)
+     * @param j the current position in the second string (1-indexed in the DP table)
+     * @param lastMatchRow the row index where the current character of s2 last appeared in s1
+     * @param lastMatchCol the column index where the current character of s1 last matched in s2
+     * @param cost the substitution cost (0 if characters match, 1 otherwise)
+     * @return the minimum cost among all operations
+     */
+    private static int computeMinimumCost(int[][] dp, int i, int j, int lastMatchRow, int lastMatchCol, int cost) {
+        int substitution = dp[i][j] + cost;
+        int insertion = dp[i + 1][j] + 1;
+        int deletion = dp[i][j + 1] + 1;
+        int transposition = dp[lastMatchRow][lastMatchCol] + i - lastMatchRow - 1 + 1 + j - lastMatchCol - 1;
+
+        return Math.min(Math.min(substitution, insertion), Math.min(deletion, transposition));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistanceTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistanceTest.java
new file mode 100644
index 000000000000..063d7bef6e1b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistanceTest.java
@@ -0,0 +1,194 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the {@code DamerauLevenshteinDistance} class.
+ * Tests cover edge cases, basic operations, and complex transposition scenarios.
+ */
+class DamerauLevenshteinDistanceTest {
+
+    @Test
+    @DisplayName("Should throw exception for null first string")
+    void testNullFirstString() {
+        assertThrows(IllegalArgumentException.class, () -> { DamerauLevenshteinDistance.distance(null, "test"); });
+    }
+
+    @Test
+    @DisplayName("Should throw exception for null second string")
+    void testNullSecondString() {
+        assertThrows(IllegalArgumentException.class, () -> { DamerauLevenshteinDistance.distance("test", null); });
+    }
+
+    @Test
+    @DisplayName("Should throw exception for both null strings")
+    void testBothNullStrings() {
+        assertThrows(IllegalArgumentException.class, () -> { DamerauLevenshteinDistance.distance(null, null); });
+    }
+
+    @Test
+    @DisplayName("Should return 0 for identical strings")
+    void testIdenticalStrings() {
+        assertEquals(0, DamerauLevenshteinDistance.distance("", ""));
+        assertEquals(0, DamerauLevenshteinDistance.distance("a", "a"));
+        assertEquals(0, DamerauLevenshteinDistance.distance("abc", "abc"));
+        assertEquals(0, DamerauLevenshteinDistance.distance("hello", "hello"));
+    }
+
+    @Test
+    @DisplayName("Should return length when one string is empty")
+    void testEmptyStrings() {
+        assertEquals(3, DamerauLevenshteinDistance.distance("", "abc"));
+        assertEquals(5, DamerauLevenshteinDistance.distance("hello", ""));
+        assertEquals(0, DamerauLevenshteinDistance.distance("", ""));
+    }
+
+    @Test
+    @DisplayName("Should handle single character insertions")
+    void testSingleInsertion() {
+        assertEquals(1, DamerauLevenshteinDistance.distance("cat", "cats"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("ab", "abc"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("", "a"));
+    }
+
+    @Test
+    @DisplayName("Should handle single character deletions")
+    void testSingleDeletion() {
+        assertEquals(1, DamerauLevenshteinDistance.distance("cats", "cat"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("abc", "ab"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("a", ""));
+    }
+
+    @Test
+    @DisplayName("Should handle single character substitutions")
+    void testSingleSubstitution() {
+        assertEquals(1, DamerauLevenshteinDistance.distance("cat", "bat"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("abc", "adc"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("x", "y"));
+    }
+
+    @Test
+    @DisplayName("Should handle adjacent character transpositions")
+    void testAdjacentTransposition() {
+        assertEquals(1, DamerauLevenshteinDistance.distance("ab", "ba"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("abc", "bac"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("hello", "ehllo"));
+    }
+
+    @Test
+    @DisplayName("Should correctly compute distance for CA to ABC")
+    void testCAtoABC() {
+        // This is the critical test case that differentiates full DL from OSA
+        // Full DL: 2 (insert A at start, insert B in middle)
+        // OSA would give: 3
+        assertEquals(2, DamerauLevenshteinDistance.distance("CA", "ABC"));
+    }
+
+    @Test
+    @DisplayName("Should handle non-adjacent transpositions")
+    void testNonAdjacentTransposition() {
+        assertEquals(2, DamerauLevenshteinDistance.distance("abc", "cba"));
+        assertEquals(3, DamerauLevenshteinDistance.distance("abcd", "dcba"));
+    }
+
+    @Test
+    @DisplayName("Should handle multiple operations")
+    void testMultipleOperations() {
+        assertEquals(3, DamerauLevenshteinDistance.distance("kitten", "sitting"));
+        assertEquals(3, DamerauLevenshteinDistance.distance("saturday", "sunday"));
+        assertEquals(5, DamerauLevenshteinDistance.distance("intention", "execution"));
+    }
+
+    @Test
+    @DisplayName("Should handle completely different strings")
+    void testCompletelyDifferentStrings() {
+        assertEquals(3, DamerauLevenshteinDistance.distance("abc", "xyz"));
+        assertEquals(4, DamerauLevenshteinDistance.distance("hello", "world"));
+    }
+
+    @Test
+    @DisplayName("Should handle strings with repeated characters")
+    void testRepeatedCharacters() {
+        assertEquals(0, DamerauLevenshteinDistance.distance("aaa", "aaa"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("aaa", "aab"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("aaa", "aba"));
+    }
+
+    @Test
+    @DisplayName("Should be symmetric")
+    void testSymmetry() {
+        assertEquals(DamerauLevenshteinDistance.distance("abc", "def"), DamerauLevenshteinDistance.distance("def", "abc"));
+        assertEquals(DamerauLevenshteinDistance.distance("hello", "world"), DamerauLevenshteinDistance.distance("world", "hello"));
+    }
+
+    @Test
+    @DisplayName("Should handle case sensitivity")
+    void testCaseSensitivity() {
+        assertEquals(1, DamerauLevenshteinDistance.distance("Hello", "hello"));
+        assertEquals(5, DamerauLevenshteinDistance.distance("HELLO", "hello"));
+    }
+
+    @Test
+    @DisplayName("Should handle single character strings")
+    void testSingleCharacterStrings() {
+        assertEquals(1, DamerauLevenshteinDistance.distance("a", "b"));
+        assertEquals(0, DamerauLevenshteinDistance.distance("a", "a"));
+        assertEquals(2, DamerauLevenshteinDistance.distance("a", "abc"));
+    }
+
+    @Test
+    @DisplayName("Should handle long strings efficiently")
+    void testLongStrings() {
+        String s1 = "abcdefghijklmnopqrstuvwxyz";
+        String s2 = "abcdefghijklmnopqrstuvwxyz";
+        assertEquals(0, DamerauLevenshteinDistance.distance(s1, s2));
+
+        String s3 = "abcdefghijklmnopqrstuvwxyz";
+        String s4 = "zyxwvutsrqponmlkjihgfedcba";
+        assertEquals(25, DamerauLevenshteinDistance.distance(s3, s4));
+    }
+
+    @Test
+    @DisplayName("Should satisfy triangle inequality")
+    void testTriangleInequality() {
+        // d(a,c) <= d(a,b) + d(b,c)
+        String a = "cat";
+        String b = "hat";
+        String c = "rat";
+
+        int ab = DamerauLevenshteinDistance.distance(a, b);
+        int bc = DamerauLevenshteinDistance.distance(b, c);
+        int ac = DamerauLevenshteinDistance.distance(a, c);
+
+        assertTrue(ac <= ab + bc);
+    }
+
+    @Test
+    @DisplayName("Should handle special characters")
+    void testSpecialCharacters() {
+        assertEquals(0, DamerauLevenshteinDistance.distance("hello!", "hello!"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("hello!", "hello?"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("a@b", "a#b"));
+    }
+
+    @Test
+    @DisplayName("Should handle numeric strings")
+    void testNumericStrings() {
+        assertEquals(1, DamerauLevenshteinDistance.distance("123", "124"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("123", "213"));
+        assertEquals(0, DamerauLevenshteinDistance.distance("999", "999"));
+    }
+
+    @Test
+    @DisplayName("Should handle unicode characters")
+    void testUnicodeCharacters() {
+        assertEquals(0, DamerauLevenshteinDistance.distance("café", "café"));
+        assertEquals(1, DamerauLevenshteinDistance.distance("café", "cafe"));
+        assertEquals(0, DamerauLevenshteinDistance.distance("你好", "你好"));
+    }
+}

From f9edb70cd74ffdee445a9a8c50a3f70078faad85 Mon Sep 17 00:00:00 2001
From: Saahil Mahato <mahatosaahil4@gmail.com>
Date: Wed, 8 Oct 2025 23:50:49 +0545
Subject: [PATCH 0990/1338] feat: add smith-waterman sequence alignment
 algorithm (#6708)

Co-authored-by: a <alexanderklmn@gmail.com>
---
 .../dynamicprogramming/SmithWaterman.java     | 56 +++++++++++++++++++
 .../dynamicprogramming/SmithWatermanTest.java | 53 ++++++++++++++++++
 2 files changed, 109 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/SmithWaterman.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/SmithWatermanTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/SmithWaterman.java b/src/main/java/com/thealgorithms/dynamicprogramming/SmithWaterman.java
new file mode 100644
index 000000000000..c0d66f68b502
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/SmithWaterman.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.dynamicprogramming;
+
+/**
+ * Smith–Waterman algorithm for local sequence alignment.
+ * Finds the highest scoring local alignment between substrings of two sequences.
+ *
+ * Time Complexity: O(n * m)
+ * Space Complexity: O(n * m)
+ */
+public final class SmithWaterman {
+
+    private SmithWaterman() {
+        // Utility Class
+    }
+
+    /**
+     * Computes the Smith–Waterman local alignment score between two strings.
+     *
+     * @param s1 first string
+     * @param s2 second string
+     * @param matchScore score for a match
+     * @param mismatchPenalty penalty for mismatch (negative)
+     * @param gapPenalty penalty for insertion/deletion (negative)
+     * @return the maximum local alignment score
+     */
+    public static int align(String s1, String s2, int matchScore, int mismatchPenalty, int gapPenalty) {
+        if (s1 == null || s2 == null) {
+            throw new IllegalArgumentException("Input strings must not be null.");
+        }
+
+        int n = s1.length();
+        int m = s2.length();
+        int maxScore = 0;
+
+        int[][] dp = new int[n + 1][m + 1];
+
+        for (int i = 1; i <= n; i++) {
+            for (int j = 1; j <= m; j++) {
+                int matchOrMismatch = (s1.charAt(i - 1) == s2.charAt(j - 1)) ? matchScore : mismatchPenalty;
+
+                dp[i][j] = Math.max(0,
+                    Math.max(Math.max(dp[i - 1][j - 1] + matchOrMismatch, // match/mismatch
+                                 dp[i - 1][j] + gapPenalty // deletion
+                                 ),
+                        dp[i][j - 1] + gapPenalty // insertion
+                        ));
+
+                if (dp[i][j] > maxScore) {
+                    maxScore = dp[i][j];
+                }
+            }
+        }
+
+        return maxScore;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/SmithWatermanTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/SmithWatermanTest.java
new file mode 100644
index 000000000000..46c47e376989
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/SmithWatermanTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+/**
+ * Unit tests for the {@code SmithWaterman} class.
+ */
+class SmithWatermanTest {
+
+    @Test
+    void testIdenticalStrings() {
+        int score = SmithWaterman.align("GATTACA", "GATTACA", 2, -1, -2);
+        assertEquals(14, score); // full match, 7*2
+    }
+
+    @Test
+    void testPartialMatch() {
+        int score = SmithWaterman.align("GATTACA", "TTAC", 2, -1, -2);
+        assertEquals(8, score); // best local alignment "TTAC"
+    }
+
+    @Test
+    void testNoMatch() {
+        int score = SmithWaterman.align("AAAA", "TTTT", 1, -1, -2);
+        assertEquals(0, score); // no alignment worth keeping
+    }
+
+    @Test
+    void testInsertionDeletion() {
+        int score = SmithWaterman.align("ACGT", "ACGGT", 1, -1, -2);
+        assertEquals(3, score); // local alignment "ACG"
+    }
+
+    @Test
+    void testEmptyStrings() {
+        assertEquals(0, SmithWaterman.align("", "", 1, -1, -2));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"null,ABC", "ABC,null", "null,null"})
+    void testNullInputs(String s1, String s2) {
+        String first = "null".equals(s1) ? null : s1;
+        String second = "null".equals(s2) ? null : s2;
+
+        IllegalArgumentException ex = assertThrows(IllegalArgumentException.class, () -> SmithWaterman.align(first, second, 1, -1, -2));
+        assertEquals("Input strings must not be null.", ex.getMessage());
+    }
+}

From 061463a4dfdb583d97a8eeb4696308a779aeba10 Mon Sep 17 00:00:00 2001
From: Saahil Mahato <mahatosaahil4@gmail.com>
Date: Thu, 9 Oct 2025 00:03:17 +0545
Subject: [PATCH 0991/1338] feat: add sieve of atkin algorithm (#6709)

* feat: add sieve of atkin algorithm

* fix: add full test coverage

* refactor: if condition braces

---------

Co-authored-by: a <alexanderklmn@gmail.com>
---
 .../com/thealgorithms/maths/SieveOfAtkin.java | 143 ++++++++++++++++++
 .../thealgorithms/maths/SieveOfAtkinTest.java |  47 ++++++
 2 files changed, 190 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/SieveOfAtkin.java
 create mode 100644 src/test/java/com/thealgorithms/maths/SieveOfAtkinTest.java

diff --git a/src/main/java/com/thealgorithms/maths/SieveOfAtkin.java b/src/main/java/com/thealgorithms/maths/SieveOfAtkin.java
new file mode 100644
index 000000000000..ee59d0784ec4
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/SieveOfAtkin.java
@@ -0,0 +1,143 @@
+package com.thealgorithms.maths;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Implementation of the Sieve of Atkin, an optimized algorithm to generate
+ * all prime numbers up to a given limit.
+ *
+ * The Sieve of Atkin uses quadratic forms and modular arithmetic to identify
+ * prime candidates, then eliminates multiples of squares. It is more efficient
+ * than the Sieve of Eratosthenes for large limits.
+ */
+public final class SieveOfAtkin {
+
+    private SieveOfAtkin() {
+        // Utlity class; prevent instantiation
+    }
+
+    /**
+     * Generates a list of all prime numbers up to the specified limit
+     * using the Sieve of Atkin algorithm.
+     *
+     * @param limit the upper bound up to which primes are generated; must be zero or positive
+     * @return a list of prime numbers up to the limit; empty if the limit is less than 2
+     */
+    public static List<Integer> generatePrimes(int limit) {
+        if (limit < 1) {
+            return List.of();
+        }
+
+        boolean[] sieve = new boolean[limit + 1];
+        int sqrtLimit = (int) Math.sqrt(limit);
+
+        markQuadraticResidues(limit, sqrtLimit, sieve);
+        eliminateMultiplesOfSquares(limit, sqrtLimit, sieve);
+
+        List<Integer> primes = new ArrayList<>();
+        if (limit >= 2) {
+            primes.add(2);
+        }
+        if (limit >= 3) {
+            primes.add(3);
+        }
+
+        for (int i = 5; i <= limit; i++) {
+            if (sieve[i]) {
+                primes.add(i);
+            }
+        }
+
+        return primes;
+    }
+
+    /**
+     * Marks numbers in the sieve as prime candidates based on quadratic residues.
+     *
+     * This method iterates over all x and y up to sqrt(limit) and applies
+     * the three quadratic forms used in the Sieve of Atkin. Numbers satisfying
+     * the modulo conditions are toggled in the sieve array.
+     *
+     * @param limit the upper bound for primes
+     * @param sqrtLimit square root of the limit
+     * @param sieve boolean array representing potential primes
+     */
+    private static void markQuadraticResidues(int limit, int sqrtLimit, boolean[] sieve) {
+        for (int x = 1; x <= sqrtLimit; x++) {
+            for (int y = 1; y <= sqrtLimit; y++) {
+                applyQuadraticForm(4 * x * x + y * y, limit, sieve, 1, 5);
+                applyQuadraticForm(3 * x * x + y * y, limit, sieve, 7);
+                applyQuadraticForm(3 * x * x - y * y, limit, sieve, 11, x > y);
+            }
+        }
+    }
+
+    /**
+     * Toggles the sieve entry for a number if it satisfies one modulo condition.
+     *
+     * @param n the number to check
+     * @param limit upper bound of primes
+     * @param sieve boolean array representing potential primes
+     * @param modulo the modulo condition number to check
+     */
+    private static void applyQuadraticForm(int n, int limit, boolean[] sieve, int modulo) {
+        if (n <= limit && n % 12 == modulo) {
+            sieve[n] ^= true;
+        }
+    }
+
+    /**
+     * Toggles the sieve entry for a number if it satisfies either of two modulo conditions.
+     *
+     * @param n the number to check
+     * @param limit upper bound of primes
+     * @param sieve boolean array representing potential primes
+     * @param modulo1 first modulo condition number to check
+     * @param modulo2 second modulo condition number to check
+     */
+    private static void applyQuadraticForm(int n, int limit, boolean[] sieve, int modulo1, int modulo2) {
+        if (n <= limit && (n % 12 == modulo1 || n % 12 == modulo2)) {
+            sieve[n] ^= true;
+        }
+    }
+
+    /**
+     * Toggles the sieve entry for a number if it satisfies the modulo condition and an additional boolean condition.
+     *
+     * This version is used for the quadratic form 3*x*x - y*y, which requires x > y.
+     *
+     * @param n the number to check
+     * @param limit upper bound of primes
+     * @param sieve boolean array representing potential primes
+     * @param modulo the modulo condition number to check
+     * @param condition an additional boolean condition that must be true
+     */
+    private static void applyQuadraticForm(int n, int limit, boolean[] sieve, int modulo, boolean condition) {
+        if (condition && n <= limit && n % 12 == modulo) {
+            sieve[n] ^= true;
+        }
+    }
+
+    /**
+     * Eliminates numbers that are multiples of squares from the sieve.
+     *
+     * All numbers that are multiples of i*i (where i is marked as prime) are
+     * marked non-prime to finalize the sieve. This ensures only actual primes remain.
+     *
+     * @param limit the upper bound for primes
+     * @param sqrtLimit square root of the limit
+     * @param sieve boolean array representing potential primes
+     */
+    private static void eliminateMultiplesOfSquares(int limit, int sqrtLimit, boolean[] sieve) {
+        for (int i = 5; i <= sqrtLimit; i++) {
+            if (!sieve[i]) {
+                continue;
+            }
+            int square = i * i;
+            for (int j = square; j <= limit; j += square) {
+                sieve[j] = false;
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/SieveOfAtkinTest.java b/src/test/java/com/thealgorithms/maths/SieveOfAtkinTest.java
new file mode 100644
index 000000000000..8eca45c9abb8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/SieveOfAtkinTest.java
@@ -0,0 +1,47 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the {@code SieveOfAtkin} class.
+ */
+class SieveOfAtkinTest {
+
+    @Test
+    void testGeneratePrimesLimit10() {
+        List<Integer> primes = SieveOfAtkin.generatePrimes(10);
+        // Assert the full expected list of primes
+        List<Integer> expected = List.of(2, 3, 5, 7);
+        assertEquals(expected, primes, "Primes up to 10 should match expected list");
+    }
+
+    @Test
+    void testGeneratePrimesLimit2() {
+        List<Integer> primes = SieveOfAtkin.generatePrimes(2);
+        List<Integer> expected = List.of(2);
+        assertEquals(expected, primes, "Primes up to 2 should include 2");
+    }
+
+    @Test
+    void testGeneratePrimesLimit1() {
+        List<Integer> primes = SieveOfAtkin.generatePrimes(1);
+        assertTrue(primes.isEmpty(), "Primes list should be empty when limit < 2");
+    }
+
+    @Test
+    void testGeneratePrimesLimit50() {
+        List<Integer> primes = SieveOfAtkin.generatePrimes(50);
+        List<Integer> expected = List.of(2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47);
+        assertEquals(expected, primes, "Primes up to 50 should match expected list");
+    }
+
+    @Test
+    void testGeneratePrimesNegativeLimit() {
+        List<Integer> primes = SieveOfAtkin.generatePrimes(-10);
+        assertTrue(primes.isEmpty(), "Primes list should be empty for negative limit");
+    }
+}

From 4fe37c3a10a054e2696a8125811b90609e69c065 Mon Sep 17 00:00:00 2001
From: Saahil Mahato <mahatosaahil4@gmail.com>
Date: Thu, 9 Oct 2025 00:12:30 +0545
Subject: [PATCH 0992/1338] =?UTF-8?q?feat:=20add=20needleman=E2=80=93wunsc?=
 =?UTF-8?q?h=20sequence=20alignment=20algorithm=20(#6707)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: a <alexanderklmn@gmail.com>
---
 .../dynamicprogramming/NeedlemanWunsch.java   | 60 +++++++++++++++++++
 .../NeedlemanWunschTest.java                  | 60 +++++++++++++++++++
 2 files changed, 120 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/NeedlemanWunsch.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/NeedlemanWunschTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/NeedlemanWunsch.java b/src/main/java/com/thealgorithms/dynamicprogramming/NeedlemanWunsch.java
new file mode 100644
index 000000000000..13b640cf0d04
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/NeedlemanWunsch.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.dynamicprogramming;
+
+/**
+ * The Needleman–Wunsch algorithm performs global sequence alignment between two strings.
+ * It computes the optimal alignment score using dynamic programming,
+ * given a scoring scheme for matches, mismatches, and gaps.
+ *
+ * Time Complexity: O(n * m)
+ * Space Complexity: O(n * m)
+ */
+public final class NeedlemanWunsch {
+
+    private NeedlemanWunsch() {
+        // Utility Class
+    }
+
+    /**
+     * Computes the Needleman–Wunsch global alignment score between two strings.
+     *
+     * @param s1 the first string
+     * @param s2 the second string
+     * @param matchScore score for a character match
+     * @param mismatchPenalty penalty for a mismatch (should be negative)
+     * @param gapPenalty penalty for inserting a gap (should be negative)
+     * @return the optimal alignment score
+     */
+    public static int align(String s1, String s2, int matchScore, int mismatchPenalty, int gapPenalty) {
+        if (s1 == null || s2 == null) {
+            throw new IllegalArgumentException("Input strings must not be null.");
+        }
+
+        int n = s1.length();
+        int m = s2.length();
+
+        int[][] dp = new int[n + 1][m + 1];
+
+        // Initialize gap penalties for first row and column
+        for (int i = 0; i <= n; i++) {
+            dp[i][0] = i * gapPenalty;
+        }
+        for (int j = 0; j <= m; j++) {
+            dp[0][j] = j * gapPenalty;
+        }
+
+        // Fill the DP matrix
+        for (int i = 1; i <= n; i++) {
+            for (int j = 1; j <= m; j++) {
+                int matchOrMismatch = (s1.charAt(i - 1) == s2.charAt(j - 1)) ? matchScore : mismatchPenalty;
+
+                dp[i][j] = Math.max(Math.max(dp[i - 1][j - 1] + matchOrMismatch, // match/mismatch
+                                        dp[i - 1][j] + gapPenalty // deletion (gap in s2)
+                                        ),
+                    dp[i][j - 1] + gapPenalty // insertion (gap in s1)
+                );
+            }
+        }
+
+        return dp[n][m];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/NeedlemanWunschTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/NeedlemanWunschTest.java
new file mode 100644
index 000000000000..f7ba5eea8bce
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/NeedlemanWunschTest.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+/**
+ * Unit Tests for the {@code NeedlemanWunsch} class
+ */
+class NeedlemanWunschTest {
+
+    @Test
+    void testIdenticalStrings() {
+        int score = NeedlemanWunsch.align("GATTACA", "GATTACA", 1, -1, -2);
+        assertEquals(7, score); // All matches, 7*1
+    }
+
+    @Test
+    void testSimpleMismatch() {
+        int score = NeedlemanWunsch.align("GATTACA", "GACTATA", 1, -1, -2);
+        assertEquals(3, score);
+    }
+
+    @Test
+    void testInsertion() {
+        int score = NeedlemanWunsch.align("GATTACA", "GATACA", 1, -1, -2);
+        // One deletion (gap penalty)
+        assertEquals(4, score);
+    }
+
+    @Test
+    void testEmptyStrings() {
+        assertEquals(0, NeedlemanWunsch.align("", "", 1, -1, -2));
+    }
+
+    @Test
+    void testOneEmpty() {
+        assertEquals(-14, NeedlemanWunsch.align("GATTACA", "", 1, -1, -2)); // 7 gaps × -2
+    }
+
+    @Test
+    void testGapHeavyAlignment() {
+        int score = NeedlemanWunsch.align("AAAA", "AA", 1, -1, -2);
+        assertEquals(-2, score); // Two matches (2*1) + two gaps (2*-2)
+    }
+
+    @ParameterizedTest
+    @CsvSource({"null,ABC", "ABC,null", "null,null"})
+    void testNullInputs(String s1, String s2) {
+        // Interpret "null" literal as Java null
+        String first = "null".equals(s1) ? null : s1;
+        String second = "null".equals(s2) ? null : s2;
+
+        IllegalArgumentException ex = assertThrows(IllegalArgumentException.class, () -> NeedlemanWunsch.align(first, second, 1, -1, -2));
+        assertEquals("Input strings must not be null.", ex.getMessage());
+    }
+}

From e22ce0005e8680dbd3de58243625ddaca9aa7929 Mon Sep 17 00:00:00 2001
From: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com>
Date: Thu, 9 Oct 2025 12:42:51 +0530
Subject: [PATCH 0993/1338] feat-Add MaximumProductSubarray (#6711)

* feat-Add MaximumProductSubarray

* feat-changes

* fix: correct MaximumProductSubarray compilation errors

* fix-lints

* fix: apply clang-format to MaximumProductSubarrayTest.java

* fix: prevent integer overflow in MaximumProductSubarray using long type
---
 .../MaximumProductSubarray.java               |  58 +++++++
 .../MaximumProductSubarrayTest.java           | 152 ++++++++++++++++++
 2 files changed, 210 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/MaximumProductSubarray.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/MaximumProductSubarrayTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/MaximumProductSubarray.java b/src/main/java/com/thealgorithms/dynamicprogramming/MaximumProductSubarray.java
new file mode 100644
index 000000000000..1c16f612e98f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/MaximumProductSubarray.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.dynamicprogramming;
+
+/**
+ * The MaximumProductSubarray class implements the algorithm to find the
+ * maximum product of a contiguous subarray within a given array of integers.
+ *
+ * <p>Given an array of integers (which may contain positive numbers, negative
+ * numbers, and zeros), this algorithm finds the contiguous subarray that has
+ * the largest product. The algorithm handles negative numbers efficiently by
+ * tracking both maximum and minimum products, since a negative number can turn
+ * a minimum product into a maximum product.</p>
+ *
+ * <p>This implementation uses a dynamic programming approach that runs in O(n)
+ * time complexity and O(1) space complexity, making it highly efficient for
+ * large arrays.</p>
+ */
+public final class MaximumProductSubarray {
+
+    private MaximumProductSubarray() {
+        // Prevent instantiation
+    }
+
+    /**
+     * Finds the maximum product of any contiguous subarray in the given array.
+     *
+     * @param nums an array of integers which may contain positive, negative,
+     *             and zero values.
+     * @return the maximum product of a contiguous subarray. Returns 0 if the
+     *         array is null or empty.
+     */
+    public static int maxProduct(int[] nums) {
+        if (nums == null || nums.length == 0) {
+            return 0;
+        }
+
+        long maxProduct = nums[0];
+        long currentMax = nums[0];
+        long currentMin = nums[0];
+
+        for (int i = 1; i < nums.length; i++) {
+            // Swap currentMax and currentMin if current number is negative
+            if (nums[i] < 0) {
+                long temp = currentMax;
+                currentMax = currentMin;
+                currentMin = temp;
+            }
+
+            // Update currentMax and currentMin
+            currentMax = Math.max(nums[i], currentMax * nums[i]);
+            currentMin = Math.min(nums[i], currentMin * nums[i]);
+
+            // Update global max product
+            maxProduct = Math.max(maxProduct, currentMax);
+        }
+
+        return (int) maxProduct;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/MaximumProductSubarrayTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/MaximumProductSubarrayTest.java
new file mode 100644
index 000000000000..0f499bf2a2f7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/MaximumProductSubarrayTest.java
@@ -0,0 +1,152 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class MaximumProductSubarrayTest {
+
+    /**
+     * Test case for an array with all positive numbers.
+     * The expected maximum product is the product of all elements.
+     */
+    @Test
+    void testAllPositiveNumbers() {
+        int[] nums = {2, 3, 4};
+        int expected = 24;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 24.");
+    }
+
+    /**
+     * Test case for an array with positive and negative numbers.
+     * The expected maximum product is 24 (subarray [2, -3, -4]).
+     */
+    @Test
+    void testMixedPositiveAndNegative() {
+        int[] nums = {2, -3, -4, 1};
+        int expected = 24;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 24.");
+    }
+
+    /**
+     * Test case for an array containing zeros.
+     * The expected maximum product is 24 (subarray [4, 6]).
+     */
+    @Test
+    void testArrayWithZeros() {
+        int[] nums = {2, 3, 0, 4, 6};
+        int expected = 24;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 24.");
+    }
+
+    /**
+     * Test case for an array with a single element.
+     * The expected maximum product is the element itself.
+     */
+    @Test
+    void testSingleElement() {
+        int[] nums = {5};
+        int expected = 5;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 5.");
+    }
+
+    /**
+     * Test case for an array with all negative numbers.
+     * The expected maximum product is 12 (subarray [-3, -4]).
+     */
+    @Test
+    void testAllNegativeNumbers() {
+        int[] nums = {-2, -3, -4};
+        int expected = 12;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 12.");
+    }
+
+    /**
+     * Test case for an array with negative numbers where odd count of negatives
+     * breaks the chain. The expected maximum product is 60 (subarray [-2, -3, 10]).
+     */
+    @Test
+    void testOddNegativeNumbers() {
+        int[] nums = {-2, -3, 10, -1};
+        int expected = 60;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 60.");
+    }
+
+    /**
+     * Test case for an empty array.
+     * The expected maximum product is 0.
+     */
+    @Test
+    void testEmptyArray() {
+        int[] nums = {};
+        int expected = 0;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 0 for an empty array.");
+    }
+
+    /**
+     * Test case for a null array.
+     * The expected maximum product is 0.
+     */
+    @Test
+    void testNullArray() {
+        int[] nums = null;
+        int expected = 0;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 0 for a null array.");
+    }
+
+    /**
+     * Test case for an array with alternating positive and negative numbers.
+     * The expected maximum product is 6 (subarray [2, 3]).
+     */
+    @Test
+    void testAlternatingNumbers() {
+        int[] nums = {2, 3, -2, 4};
+        int expected = 6;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 6.");
+    }
+
+    /**
+     * Test case for an array with large positive and negative numbers.
+     * The expected maximum product is 360 (subarray [6, -3, -20]).
+     */
+    @Test
+    void testLargeNumbers() {
+        int[] nums = {6, -3, -20, 0, 5};
+        int expected = 360;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 360.");
+    }
+
+    /**
+     * Test case for an array with single negative number.
+     * The expected maximum product is the negative number itself.
+     */
+    @Test
+    void testSingleNegativeElement() {
+        int[] nums = {-8};
+        int expected = -8;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be -8.");
+    }
+
+    /**
+     * Test case for an array with multiple zeros.
+     * The expected maximum product is 6 (subarray [2, 3]).
+     */
+    @Test
+    void testMultipleZeros() {
+        int[] nums = {0, 2, 3, 0, 4};
+        int expected = 6;
+        int actual = MaximumProductSubarray.maxProduct(nums);
+        assertEquals(expected, actual, "The maximum product should be 6.");
+    }
+}

From b1aa896e1771ee2bcc710fe63c08273a61cd196d Mon Sep 17 00:00:00 2001
From: Yash Rajput <52812070+the-yash-rajput@users.noreply.github.com>
Date: Thu, 9 Oct 2025 12:53:58 +0530
Subject: [PATCH 0994/1338] Added GroundToGroundProjectileMotion (#6714)

* Added GroundToGroundProjectileMotion

* Fix checkstyle issues.

* Fix checkstyle issues.
---
 .../GroundToGroundProjectileMotion.java       |  90 +++++++++++
 .../GroundToGroundProjectileMotionTest.java   | 149 ++++++++++++++++++
 2 files changed, 239 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/physics/GroundToGroundProjectileMotion.java
 create mode 100644 src/test/java/com/thealgorithms/physics/GroundToGroundProjectileMotionTest.java

diff --git a/src/main/java/com/thealgorithms/physics/GroundToGroundProjectileMotion.java b/src/main/java/com/thealgorithms/physics/GroundToGroundProjectileMotion.java
new file mode 100644
index 000000000000..a8d7ac63a186
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/GroundToGroundProjectileMotion.java
@@ -0,0 +1,90 @@
+package com.thealgorithms.physics;
+
+/**
+ * Ground to ground projectile motion calculator
+ *
+ * Ground to ground projectile motion is when a projectile's trajectory
+ * starts at the ground, reaches the apex, then falls back on the ground.
+ *
+ * @author [Yash Rajput](https://github.com/the-yash-rajput)
+ */
+public final class GroundToGroundProjectileMotion {
+
+    private GroundToGroundProjectileMotion() {
+        throw new AssertionError("No instances.");
+    }
+
+    /** Standard gravity constant (m/s^2) */
+    private static final double GRAVITY = 9.80665;
+
+    /**
+     * Convert degrees to radians
+     *
+     * @param degrees Angle in degrees
+     * @return Angle in radians
+     */
+    private static double degreesToRadians(double degrees) {
+        return degrees * (Math.PI / 180.0);
+    }
+
+    /**
+     * Calculate the time of flight
+     *
+     * @param initialVelocity The starting velocity of the projectile (m/s)
+     * @param angle The angle that the projectile is launched at in degrees
+     * @return The time that the projectile is in the air for (seconds)
+     */
+    public static double timeOfFlight(double initialVelocity, double angle) {
+        return timeOfFlight(initialVelocity, angle, GRAVITY);
+    }
+
+    /**
+     * Calculate the time of flight with custom gravity
+     *
+     * @param initialVelocity The starting velocity of the projectile (m/s)
+     * @param angle The angle that the projectile is launched at in degrees
+     * @param gravity The value used for the gravity constant (m/s^2)
+     * @return The time that the projectile is in the air for (seconds)
+     */
+    public static double timeOfFlight(double initialVelocity, double angle, double gravity) {
+        double viy = initialVelocity * Math.sin(degreesToRadians(angle));
+        return 2.0 * viy / gravity;
+    }
+
+    /**
+     * Calculate the horizontal distance that the projectile travels
+     *
+     * @param initialVelocity The starting velocity of the projectile (m/s)
+     * @param angle The angle that the projectile is launched at in degrees
+     * @param time The time that the projectile is in the air (seconds)
+     * @return Horizontal distance that the projectile travels (meters)
+     */
+    public static double horizontalRange(double initialVelocity, double angle, double time) {
+        double vix = initialVelocity * Math.cos(degreesToRadians(angle));
+        return vix * time;
+    }
+
+    /**
+     * Calculate the max height of the projectile
+     *
+     * @param initialVelocity The starting velocity of the projectile (m/s)
+     * @param angle The angle that the projectile is launched at in degrees
+     * @return The max height that the projectile reaches (meters)
+     */
+    public static double maxHeight(double initialVelocity, double angle) {
+        return maxHeight(initialVelocity, angle, GRAVITY);
+    }
+
+    /**
+     * Calculate the max height of the projectile with custom gravity
+     *
+     * @param initialVelocity The starting velocity of the projectile (m/s)
+     * @param angle The angle that the projectile is launched at in degrees
+     * @param gravity The value used for the gravity constant (m/s^2)
+     * @return The max height that the projectile reaches (meters)
+     */
+    public static double maxHeight(double initialVelocity, double angle, double gravity) {
+        double viy = initialVelocity * Math.sin(degreesToRadians(angle));
+        return Math.pow(viy, 2) / (2.0 * gravity);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/GroundToGroundProjectileMotionTest.java b/src/test/java/com/thealgorithms/physics/GroundToGroundProjectileMotionTest.java
new file mode 100644
index 000000000000..9d7e11777983
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/GroundToGroundProjectileMotionTest.java
@@ -0,0 +1,149 @@
+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * JUnit test class for GroundToGroundProjectileMotion
+ *
+ * Contains unit tests for projectile motion calculations using JUnit 5
+ */
+public class GroundToGroundProjectileMotionTest {
+
+    private static final double EPSILON = 0.001; // Tolerance for floating point comparison
+
+    @Test
+    @DisplayName("Test time of flight calculation")
+    public void testTimeOfFlight() {
+        // Arrange
+        double initialVelocity = 5.0;
+        double angle = 40.0;
+        double expectedTimeOfFlight = 0.655;
+
+        // Act
+        double flightTimeOutput = GroundToGroundProjectileMotion.timeOfFlight(initialVelocity, angle);
+        flightTimeOutput = Math.round(flightTimeOutput * 1000.0) / 1000.0;
+
+        // Assert
+        assertEquals(expectedTimeOfFlight, flightTimeOutput, EPSILON, "Time of flight should be " + expectedTimeOfFlight + " seconds");
+
+        System.out.println("Projectile Flight Time Test");
+        System.out.println("Input Initial Velocity: " + initialVelocity + " m/s");
+        System.out.println("Input Angle: " + angle + " degrees");
+        System.out.println("Expected Output: " + expectedTimeOfFlight + " seconds");
+        System.out.println("Actual Output: " + flightTimeOutput + " seconds");
+        System.out.println("TEST PASSED\n");
+    }
+
+    @Test
+    @DisplayName("Test horizontal range calculation")
+    public void testHorizontalRange() {
+        // Arrange
+        double initialVelocity = 5.0;
+        double angle = 40.0;
+        double flightTime = 0.655;
+        double expectedHorizontalRange = 2.51;
+
+        // Act
+        double horizontalRangeOutput = GroundToGroundProjectileMotion.horizontalRange(initialVelocity, angle, flightTime);
+        horizontalRangeOutput = Math.round(horizontalRangeOutput * 100.0) / 100.0;
+
+        // Assert
+        assertEquals(expectedHorizontalRange, horizontalRangeOutput, EPSILON, "Horizontal range should be " + expectedHorizontalRange + " meters");
+
+        System.out.println("Projectile Horizontal Range Test");
+        System.out.println("Input Initial Velocity: " + initialVelocity + " m/s");
+        System.out.println("Input Angle: " + angle + " degrees");
+        System.out.println("Input Time Of Flight: " + flightTime + " seconds");
+        System.out.println("Expected Output: " + expectedHorizontalRange + " meters");
+        System.out.println("Actual Output: " + horizontalRangeOutput + " meters");
+        System.out.println("TEST PASSED\n");
+    }
+
+    @Test
+    @DisplayName("Test max height calculation")
+    public void testMaxHeight() {
+        // Arrange
+        double initialVelocity = 5.0;
+        double angle = 40.0;
+        double expectedMaxHeight = 0.527; // Updated to match actual calculation
+
+        // Act
+        double maxHeightOutput = GroundToGroundProjectileMotion.maxHeight(initialVelocity, angle);
+        maxHeightOutput = Math.round(maxHeightOutput * 1000.0) / 1000.0;
+
+        // Assert
+        assertEquals(expectedMaxHeight, maxHeightOutput, EPSILON, "Max height should be " + expectedMaxHeight + " meters");
+
+        System.out.println("Projectile Max Height Test");
+        System.out.println("Input Initial Velocity: " + initialVelocity + " m/s");
+        System.out.println("Input Angle: " + angle + " degrees");
+        System.out.println("Expected Output: " + expectedMaxHeight + " meters");
+        System.out.println("Actual Output: " + maxHeightOutput + " meters");
+        System.out.println("TEST PASSED\n");
+    }
+
+    @Test
+    @DisplayName("Test time of flight with custom gravity")
+    public void testTimeOfFlightWithCustomGravity() {
+        // Arrange
+        double initialVelocity = 10.0;
+        double angle = 45.0;
+        double customGravity = 1.62; // Moon gravity (m/s^2)
+
+        // Act
+        double flightTime = GroundToGroundProjectileMotion.timeOfFlight(initialVelocity, angle, customGravity);
+
+        // Assert
+        assertTrue(flightTime > 0, "Flight time should be positive");
+        assertTrue(flightTime > 8.0, "Flight time on moon should be longer than on Earth");
+
+        System.out.println("Custom Gravity Test (Moon)");
+        System.out.println("Input Initial Velocity: " + initialVelocity + " m/s");
+        System.out.println("Input Angle: " + angle + " degrees");
+        System.out.println("Gravity: " + customGravity + " m/s^2");
+        System.out.println("Flight Time: " + flightTime + " seconds");
+        System.out.println("TEST PASSED\n");
+    }
+
+    @Test
+    @DisplayName("Test projectile at 90 degrees (straight up)")
+    public void testVerticalProjectile() {
+        // Arrange
+        double initialVelocity = 20.0;
+        double angle = 90.0;
+
+        // Act
+        double horizontalRange = GroundToGroundProjectileMotion.horizontalRange(initialVelocity, angle, 1.0);
+
+        // Assert
+        assertEquals(0.0, horizontalRange, EPSILON, "Horizontal range should be zero for vertical launch");
+
+        System.out.println("Vertical Projectile Test");
+        System.out.println("Input Angle: " + angle + " degrees");
+        System.out.println("Horizontal Range: " + horizontalRange + " meters");
+        System.out.println("TEST PASSED\n");
+    }
+
+    @Test
+    @DisplayName("Test projectile at 0 degrees (horizontal)")
+    public void testHorizontalProjectile() {
+        // Arrange
+        double initialVelocity = 15.0;
+        double angle = 0.0;
+
+        // Act
+        double maxHeight = GroundToGroundProjectileMotion.maxHeight(initialVelocity, angle);
+
+        // Assert
+        assertEquals(0.0, maxHeight, EPSILON, "Max height should be zero for horizontal launch");
+
+        System.out.println("Horizontal Projectile Test");
+        System.out.println("Input Angle: " + angle + " degrees");
+        System.out.println("Max Height: " + maxHeight + " meters");
+        System.out.println("TEST PASSED\n");
+    }
+}

From 16557a9b817f94aa9836644ee23942ca9bc7ae15 Mon Sep 17 00:00:00 2001
From: CrodiYa <Crodis@yandex.ru>
Date: Thu, 9 Oct 2025 20:20:19 +0300
Subject: [PATCH 0995/1338] Feature iterative flood fill (#6584)

* feat: FloodFill Algorithm with iterative approach

- nested class Point: helper class, represents point in 2D field (x,y)
- shouldSkipPixel method: helper method to validate point
- floodFill method: iterative version of floodFill, uses Queue to add and poll Points and change it color if allowed

* feat: tests for IterativeFloodFill

-same tests as for normal floodFill and test for a big image

* docs: add link to floodFill algorithm

* codeStyle fix

* tests: add tests for edge cases

* codeStyle fix

* codeStyle fix

* codeStyle fix

* refactor: reorganize structure and add JavaDoc

- Move private methods after public methods for better readability
- Add class-level JavaDoc documentation with algorithm description and links to references
---
 .../others/IterativeFloodFill.java            | 102 +++++++++++
 .../others/IterativeFloodFillTest.java        | 163 ++++++++++++++++++
 2 files changed, 265 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/others/IterativeFloodFill.java
 create mode 100644 src/test/java/com/thealgorithms/others/IterativeFloodFillTest.java

diff --git a/src/main/java/com/thealgorithms/others/IterativeFloodFill.java b/src/main/java/com/thealgorithms/others/IterativeFloodFill.java
new file mode 100644
index 000000000000..3ef90369bd52
--- /dev/null
+++ b/src/main/java/com/thealgorithms/others/IterativeFloodFill.java
@@ -0,0 +1,102 @@
+package com.thealgorithms.others;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+/**
+ * Implementation of the Flood Fill algorithm using an iterative BFS (Breadth-First Search) approach.
+ *
+ * <p>The Flood Fill algorithm is used to fill connected areas in an image with a new color, starting from a specified point.
+ * This implementation uses an iterative BFS approach with a queue
+ * instead of recursion to avoid stack overflow issues with large images.</p>
+ *
+ * <p><b>Implementation Features:</b></p>
+ * <ul>
+ *   <li>Supports 8-connected filling (horizontal, vertical, and diagonal directions)</li>
+ *   <li>Uses BFS traversal through {@link java.util.Queue}</li>
+ *   <li>Includes nested {@code Point} class to represent pixel coordinates</li>
+ *   <li>Iterative approach avoids stack overflow for large images</li>
+ * </ul>
+ *
+ * <p><b>Time Complexity:</b> O(M × N) where M and N are the dimensions of the image</p>
+ * <p><b>Space Complexity:</b> O(M × N) in the worst case the queue stores every pixel</p>
+ *
+ * @see <a href="https://www.geeksforgeeks.org/dsa/flood-fill-algorithm">Flood Fill Algorithm - GeeksforGeeks</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Flood_fill">Flood Fill Algorithm - Wikipedia</a>
+ */
+public final class IterativeFloodFill {
+    private IterativeFloodFill() {
+    }
+
+    /**
+     * Iteratively fill the 2D image with new color
+     *
+     * @param image    The image to be filled
+     * @param x        The x co-ordinate at which color is to be filled
+     * @param y        The y co-ordinate at which color is to be filled
+     * @param newColor The new color which to be filled in the image
+     * @param oldColor The old color which is to be replaced in the image
+     * @see <a href=https://www.geeksforgeeks.org/dsa/flood-fill-algorithm>FloodFill BFS<a/>
+     */
+    public static void floodFill(final int[][] image, final int x, final int y, final int newColor, final int oldColor) {
+        if (image.length == 0 || image[0].length == 0 || newColor == oldColor || shouldSkipPixel(image, x, y, oldColor)) {
+            return;
+        }
+
+        Queue<Point> queue = new LinkedList<>();
+        queue.add(new Point(x, y));
+
+        int[] dx = {0, 0, -1, 1, 1, -1, 1, -1};
+        int[] dy = {-1, 1, 0, 0, -1, 1, 1, -1};
+
+        while (!queue.isEmpty()) {
+            Point currPoint = queue.poll();
+
+            if (shouldSkipPixel(image, currPoint.x, currPoint.y, oldColor)) {
+                continue;
+            }
+
+            image[currPoint.x][currPoint.y] = newColor;
+
+            for (int i = 0; i < 8; i++) {
+                int curX = currPoint.x + dx[i];
+                int curY = currPoint.y + dy[i];
+
+                if (!shouldSkipPixel(image, curX, curY, oldColor)) {
+                    queue.add(new Point(curX, curY));
+                }
+            }
+        }
+    }
+
+    /**
+     * Represents a point in 2D space with integer coordinates.
+     */
+    private static class Point {
+        final int x;
+        final int y;
+
+        Point(final int x, final int y) {
+            this.x = x;
+            this.y = y;
+        }
+    }
+
+    /**
+     * Checks if a pixel should be skipped during flood fill operation.
+     *
+     * @param image    The image to get boundaries
+     * @param x        The x co-ordinate of pixel to check
+     * @param y        The y co-ordinate of pixel to check
+     * @param oldColor The old color which is to be replaced in the image
+     * @return {@code true} if pixel should be skipped, else {@code false}
+     */
+    private static boolean shouldSkipPixel(final int[][] image, final int x, final int y, final int oldColor) {
+
+        if (x < 0 || x >= image.length || y < 0 || y >= image[0].length || image[x][y] != oldColor) {
+            return true;
+        }
+
+        return false;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/others/IterativeFloodFillTest.java b/src/test/java/com/thealgorithms/others/IterativeFloodFillTest.java
new file mode 100644
index 000000000000..560f1df68e81
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/IterativeFloodFillTest.java
@@ -0,0 +1,163 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+import org.junit.jupiter.api.Test;
+
+class IterativeFloodFillTest {
+
+    @Test
+    void testForEmptyImage() {
+        int[][] image = {};
+        int[][] expected = {};
+
+        IterativeFloodFill.floodFill(image, 4, 5, 3, 2);
+        assertArrayEquals(expected, image);
+    }
+
+    @Test
+    void testForSingleElementImage() {
+        int[][] image = {{1}};
+        int[][] expected = {{3}};
+
+        IterativeFloodFill.floodFill(image, 0, 0, 3, 1);
+        assertArrayEquals(expected, image);
+    }
+
+    @Test
+    void testForEmptyRow() {
+        int[][] image = {{}};
+        int[][] expected = {{}};
+
+        IterativeFloodFill.floodFill(image, 4, 5, 3, 2);
+        assertArrayEquals(expected, image);
+    }
+
+    @Test
+    void testForImageOne() {
+        int[][] image = {
+            {0, 0, 0, 0, 0, 0, 0},
+            {0, 3, 3, 3, 3, 0, 0},
+            {0, 3, 1, 1, 5, 0, 0},
+            {0, 3, 1, 1, 5, 5, 3},
+            {0, 3, 5, 5, 1, 1, 3},
+            {0, 0, 0, 5, 1, 1, 3},
+            {0, 0, 0, 3, 3, 3, 3},
+        };
+
+        int[][] expected = {
+            {0, 0, 0, 0, 0, 0, 0},
+            {0, 3, 3, 3, 3, 0, 0},
+            {0, 3, 2, 2, 5, 0, 0},
+            {0, 3, 2, 2, 5, 5, 3},
+            {0, 3, 5, 5, 2, 2, 3},
+            {0, 0, 0, 5, 2, 2, 3},
+            {0, 0, 0, 3, 3, 3, 3},
+        };
+
+        IterativeFloodFill.floodFill(image, 2, 2, 2, 1);
+        assertArrayEquals(expected, image);
+    }
+
+    @Test
+    void testForImageTwo() {
+        int[][] image = {
+            {0, 0, 1, 1, 0, 0, 0},
+            {1, 1, 3, 3, 3, 0, 0},
+            {1, 3, 1, 1, 5, 0, 0},
+            {0, 3, 1, 1, 5, 5, 3},
+            {0, 3, 5, 5, 1, 1, 3},
+            {0, 0, 0, 5, 1, 1, 3},
+            {0, 0, 0, 1, 3, 1, 3},
+        };
+
+        int[][] expected = {
+            {0, 0, 2, 2, 0, 0, 0},
+            {2, 2, 3, 3, 3, 0, 0},
+            {2, 3, 2, 2, 5, 0, 0},
+            {0, 3, 2, 2, 5, 5, 3},
+            {0, 3, 5, 5, 2, 2, 3},
+            {0, 0, 0, 5, 2, 2, 3},
+            {0, 0, 0, 2, 3, 2, 3},
+        };
+
+        IterativeFloodFill.floodFill(image, 2, 2, 2, 1);
+        assertArrayEquals(expected, image);
+    }
+
+    @Test
+    void testForImageThree() {
+        int[][] image = {
+            {1, 1, 2, 3, 1, 1, 1},
+            {1, 0, 0, 1, 0, 0, 1},
+            {1, 1, 1, 0, 3, 1, 2},
+        };
+
+        int[][] expected = {
+            {4, 4, 2, 3, 4, 4, 4},
+            {4, 0, 0, 4, 0, 0, 4},
+            {4, 4, 4, 0, 3, 4, 2},
+        };
+
+        IterativeFloodFill.floodFill(image, 0, 1, 4, 1);
+        assertArrayEquals(expected, image);
+    }
+
+    @Test
+    void testForSameNewAndOldColor() {
+        int[][] image = {{1, 1, 2}, {1, 0, 0}, {1, 1, 1}};
+
+        int[][] expected = {{1, 1, 2}, {1, 0, 0}, {1, 1, 1}};
+
+        IterativeFloodFill.floodFill(image, 0, 1, 1, 1);
+        assertArrayEquals(expected, image);
+    }
+
+    @Test
+    void testForBigImage() {
+        int[][] image = new int[100][100];
+
+        assertDoesNotThrow(() -> IterativeFloodFill.floodFill(image, 0, 0, 1, 0));
+    }
+
+    @Test
+    void testForBelowZeroX() {
+        int[][] image = {{1, 1, 2}, {1, 0, 0}, {1, 1, 1}};
+
+        int[][] expected = {{1, 1, 2}, {1, 0, 0}, {1, 1, 1}};
+
+        IterativeFloodFill.floodFill(image, -1, 1, 1, 0);
+        assertArrayEquals(expected, image);
+    }
+
+    @Test
+    void testForBelowZeroY() {
+        int[][] image = {{1, 1, 2}, {1, 0, 0}, {1, 1, 1}};
+
+        int[][] expected = {{1, 1, 2}, {1, 0, 0}, {1, 1, 1}};
+
+        IterativeFloodFill.floodFill(image, 1, -1, 1, 0);
+        assertArrayEquals(expected, image);
+    }
+
+    @Test
+    void testForAboveBoundaryX() {
+        int[][] image = {{1, 1, 2}, {1, 0, 0}, {1, 1, 1}};
+
+        int[][] expected = {{1, 1, 2}, {1, 0, 0}, {1, 1, 1}};
+
+        IterativeFloodFill.floodFill(image, 100, 1, 1, 0);
+        assertArrayEquals(expected, image);
+    }
+
+    @Test
+    void testForAboveBoundaryY() {
+        int[][] image = {{1, 1, 2}, {1, 0, 0}, {1, 1, 1}};
+
+        int[][] expected = {{1, 1, 2}, {1, 0, 0}, {1, 1, 1}};
+
+        IterativeFloodFill.floodFill(image, 1, 100, 1, 0);
+        assertArrayEquals(expected, image);
+    }
+}

From e788111420b8c1182f4f79157c342eae93769caf Mon Sep 17 00:00:00 2001
From: Banula Kumarage <63106638+BanulaKumarage@users.noreply.github.com>
Date: Thu, 9 Oct 2025 22:58:06 +0530
Subject: [PATCH 0996/1338] Dev: Added Germain and Safe prime utility class
 (#6611)

* feat: add Germain and Safe prime utility class with unit tests

* refactor the code

* fixed identified bugs

* fixed identified remaining bugs

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
---
 .../maths/GermainPrimeAndSafePrime.java       | 63 +++++++++++++++++++
 .../maths/GermainPrimeAndSafePrimeTest.java   | 49 +++++++++++++++
 2 files changed, 112 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/GermainPrimeAndSafePrime.java
 create mode 100644 src/test/java/com/thealgorithms/maths/GermainPrimeAndSafePrimeTest.java

diff --git a/src/main/java/com/thealgorithms/maths/GermainPrimeAndSafePrime.java b/src/main/java/com/thealgorithms/maths/GermainPrimeAndSafePrime.java
new file mode 100644
index 000000000000..180bbdfe9ac3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/GermainPrimeAndSafePrime.java
@@ -0,0 +1,63 @@
+package com.thealgorithms.maths;
+
+import com.thealgorithms.maths.Prime.PrimeCheck;
+
+/**
+ * A utility class to check whether a number is a Germain prime or a Safe prime.
+ *
+ * <p>This class provides methods to:
+ * <ul>
+ *   <li>Check if a number is a Germain prime</li>
+ *   <li>Check if a number is a Safe prime</li>
+ * </ul>
+ *
+ * <p>Definitions:
+ * <ul>
+ *   <li>A Germain prime is a prime number p such that 2p + 1 is also prime.</li>
+ *   <li>A Safe prime is a prime number p such that (p - 1) / 2 is also prime.</li>
+ * </ul>
+ *
+ * <p>This class is final and cannot be instantiated.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Safe_and_Sophie_Germain_primes">Wikipedia: Safe and Sophie Germain primes</a>
+ */
+public final class GermainPrimeAndSafePrime {
+
+    // Private constructor to prevent instantiation
+    private GermainPrimeAndSafePrime() {
+    }
+
+    /**
+     * Checks if a number is a Germain prime.
+     *
+     * <p>A Germain prime is a prime number p such that 2p + 1 is also prime.
+     *
+     * @param number the number to check; must be a positive integer
+     * @return {@code true} if the number is a Germain prime, {@code false} otherwise
+     * @throws IllegalArgumentException if the input number is less than 1
+     */
+    public static boolean isGermainPrime(int number) {
+        if (number < 1) {
+            throw new IllegalArgumentException("Input value must be a positive integer. Input value: " + number);
+        }
+        // A number is a Germain prime if it is prime and 2 * number + 1 is also prime
+        return PrimeCheck.isPrime(number) && PrimeCheck.isPrime(2 * number + 1);
+    }
+
+    /**
+     * Checks if a number is a Safe prime.
+     *
+     * <p>A Safe prime is a prime number p such that (p - 1) / 2 is also prime.
+     *
+     * @param number the number to check; must be a positive integer
+     * @return {@code true} if the number is a Safe prime, {@code false} otherwise
+     * @throws IllegalArgumentException if the input number is less than 1
+     */
+    public static boolean isSafePrime(int number) {
+        if (number < 1) {
+            throw new IllegalArgumentException("Input value must be a positive integer. Input value: " + number);
+        }
+        // A number is a Safe prime if it is prime, (number - 1) is even, and (number - 1) / 2 is prime
+        return ((number - 1) % 2 == 0) && PrimeCheck.isPrime(number) && PrimeCheck.isPrime((number - 1) / 2);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/GermainPrimeAndSafePrimeTest.java b/src/test/java/com/thealgorithms/maths/GermainPrimeAndSafePrimeTest.java
new file mode 100644
index 000000000000..069d1156295f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/GermainPrimeAndSafePrimeTest.java
@@ -0,0 +1,49 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class GermainPrimeAndSafePrimeTest {
+
+    static Stream<Arguments> provideNumbersForGermainPrimes() {
+        return Stream.of(Arguments.of(2, Boolean.TRUE), Arguments.of(3, Boolean.TRUE), Arguments.of(5, Boolean.TRUE), Arguments.of(11, Boolean.TRUE), Arguments.of(23, Boolean.TRUE), Arguments.of(293, Boolean.TRUE), Arguments.of(4, Boolean.FALSE), Arguments.of(7, Boolean.FALSE),
+            Arguments.of(9, Boolean.FALSE), Arguments.of(1, Boolean.FALSE));
+    }
+
+    static Stream<Arguments> provideNumbersForSafePrimes() {
+        return Stream.of(Arguments.of(5, Boolean.TRUE), Arguments.of(7, Boolean.TRUE), Arguments.of(11, Boolean.TRUE), Arguments.of(23, Boolean.TRUE), Arguments.of(1283, Boolean.TRUE), Arguments.of(4, Boolean.FALSE), Arguments.of(13, Boolean.FALSE), Arguments.of(9, Boolean.FALSE),
+            Arguments.of(1, Boolean.FALSE));
+    }
+
+    static Stream<Integer> provideNegativeNumbers() {
+        return Stream.of(-10, -1, 0);
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideNumbersForGermainPrimes")
+    @DisplayName("Check whether a number is a Germain prime")
+    void testValidGermainPrimes(int number, boolean expected) {
+        assertEquals(expected, GermainPrimeAndSafePrime.isGermainPrime(number));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideNumbersForSafePrimes")
+    @DisplayName("Check whether a number is a Safe prime")
+    void testValidSafePrimes(int number, boolean expected) {
+        assertEquals(expected, GermainPrimeAndSafePrime.isSafePrime(number));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideNegativeNumbers")
+    @DisplayName("Negative numbers and zero should throw IllegalArgumentException")
+    void testNegativeNumbersThrowException(int number) {
+        assertThrows(IllegalArgumentException.class, () -> GermainPrimeAndSafePrime.isGermainPrime(number));
+        assertThrows(IllegalArgumentException.class, () -> GermainPrimeAndSafePrime.isSafePrime(number));
+    }
+}

From 3c071c4e08e03910045634a80039ac47401f1a58 Mon Sep 17 00:00:00 2001
From: Ruturaj Jadhav <ruturajjadhav122@gmail.com>
Date: Thu, 9 Oct 2025 23:01:56 +0530
Subject: [PATCH 0997/1338] Added HappyNumber algorithm in maths section
 (#6571)

* Added HappyNumber algorithm in maths section

* Fix Checkstyle: remove trailing spaces in HappyNumber

* Fix formatting: remove trailing spaces and apply clang-format

* Update HappyNumberTest.java

* Removed old HappyNumbersSeq.java as replaced by new HappyNumber.java
---
 .../com/thealgorithms/maths/HappyNumber.java  | 57 +++++++++++++++++++
 .../thealgorithms/others/HappyNumbersSeq.java | 39 -------------
 .../thealgorithms/maths/HappyNumberTest.java  | 32 +++++++++++
 3 files changed, 89 insertions(+), 39 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/maths/HappyNumber.java
 delete mode 100644 src/main/java/com/thealgorithms/others/HappyNumbersSeq.java
 create mode 100644 src/test/java/com/thealgorithms/maths/HappyNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/HappyNumber.java b/src/main/java/com/thealgorithms/maths/HappyNumber.java
new file mode 100644
index 000000000000..bfe746953b33
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/HappyNumber.java
@@ -0,0 +1,57 @@
+package com.thealgorithms.maths;
+
+/**
+ * A Happy Number is defined as a number which eventually reaches 1 when replaced
+ * by the sum of the squares of each digit.
+ * If it falls into a cycle that does not include 1, then it is not a happy number.
+
+ * Example:
+ * 19 → 1² + 9² = 82
+ * 82 → 8² + 2² = 68
+ * 68 → 6² + 8² = 100
+ * 100 → 1² + 0² + 0² = 1 → Happy Number!
+ */
+public final class HappyNumber {
+
+    private HappyNumber() {
+    }
+
+    /**
+     * Checks whether the given number is a Happy Number.
+     * Uses Floyd’s Cycle Detection algorithm (tortoise and hare method)
+     * to detect loops efficiently.
+     *
+     * @param n The number to check
+     * @return true if n is a Happy Number, false otherwise
+     */
+    public static boolean isHappy(int n) {
+        int slow = n;
+        int fast = n;
+
+        do {
+            slow = sumOfSquares(slow); // move 1 step
+            fast = sumOfSquares(sumOfSquares(fast)); // move 2 steps
+        } while (slow != fast);
+
+        return slow == 1; // If cycle ends in 1 → Happy number
+    }
+
+    /**
+     * Calculates the sum of squares of the digits of a number.
+     *
+     * Example:
+     * num = 82 → 8² + 2² = 64 + 4 = 68
+     *
+     * @param num The number to calculate sum of squares of digits
+     * @return The sum of squares of the digits
+     */
+    private static int sumOfSquares(int num) {
+        int sum = 0;
+        while (num > 0) {
+            int digit = num % 10;
+            sum += digit * digit;
+            num /= 10;
+        }
+        return sum;
+    }
+}
diff --git a/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java b/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java
deleted file mode 100644
index 0ae1e451bc6a..000000000000
--- a/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java
+++ /dev/null
@@ -1,39 +0,0 @@
-package com.thealgorithms.others;
-
-import java.util.Arrays;
-import java.util.HashSet;
-import java.util.Scanner;
-import java.util.Set;
-
-public final class HappyNumbersSeq {
-    private HappyNumbersSeq() {
-    }
-
-    private static final Set<Integer> CYCLE_NUMS = new HashSet<>(Arrays.asList(4, 16, 20, 37, 58, 145));
-
-    public static void main(String[] args) {
-        Scanner in = new Scanner(System.in);
-        System.out.print("Enter number: ");
-        int n = in.nextInt();
-        while (n != 1 && !isSad(n)) {
-            System.out.print(n + " ");
-            n = sumSquares(n);
-        }
-        String res = n == 1 ? "1 Happy number" : "Sad number";
-        System.out.println(res);
-        in.close();
-    }
-
-    private static int sumSquares(int n) {
-        int s = 0;
-        for (; n > 0; n /= 10) {
-            int r = n % 10;
-            s += r * r;
-        }
-        return s;
-    }
-
-    private static boolean isSad(int n) {
-        return CYCLE_NUMS.contains(n);
-    }
-}
diff --git a/src/test/java/com/thealgorithms/maths/HappyNumberTest.java b/src/test/java/com/thealgorithms/maths/HappyNumberTest.java
new file mode 100644
index 000000000000..4b7cb795406f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/HappyNumberTest.java
@@ -0,0 +1,32 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class HappyNumberTest {
+
+    @Test
+    void testHappyNumbers() {
+        // Known happy numbers
+        assertTrue(HappyNumber.isHappy(1));
+        assertTrue(HappyNumber.isHappy(7));
+        assertTrue(HappyNumber.isHappy(19));
+        assertTrue(HappyNumber.isHappy(100));
+    }
+
+    @Test
+    void testUnhappyNumbers() {
+        // Known unhappy numbers
+        assertFalse(HappyNumber.isHappy(2));
+        assertFalse(HappyNumber.isHappy(4));
+        assertFalse(HappyNumber.isHappy(20));
+    }
+
+    @Test
+    void testLargeNumber() {
+        // Just to check behavior with larger input
+        assertTrue(HappyNumber.isHappy(1000000)); // reduces to 1 eventually
+    }
+}

From 61fbb1855cd403fe9ff1bff0caf1c7d9359fd612 Mon Sep 17 00:00:00 2001
From: Banula Kumarage <63106638+BanulaKumarage@users.noreply.github.com>
Date: Fri, 10 Oct 2025 00:06:20 +0530
Subject: [PATCH 0998/1338] Dev: Add Zeller's Congruence utility class to
 calculate the day of the week (#6614)

* Add Zeller's Congruence utility class and unit tests

* fixed identified bugs

* fixed pmd failure
---
 .../maths/ZellersCongruence.java              | 107 ++++++++++++++++++
 .../maths/ZellersCongruenceTest.java          |  36 ++++++
 2 files changed, 143 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/ZellersCongruence.java
 create mode 100644 src/test/java/com/thealgorithms/maths/ZellersCongruenceTest.java

diff --git a/src/main/java/com/thealgorithms/maths/ZellersCongruence.java b/src/main/java/com/thealgorithms/maths/ZellersCongruence.java
new file mode 100644
index 000000000000..95ed061ac17f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/ZellersCongruence.java
@@ -0,0 +1,107 @@
+package com.thealgorithms.maths;
+
+import java.time.DateTimeException;
+import java.time.LocalDate;
+import java.util.Objects;
+
+/**
+ * A utility class for calculating the day of the week for a given date using Zeller's Congruence.
+ *
+ * <p>Zeller's Congruence is an algorithm devised by Christian Zeller in the 19th century to calculate
+ * the day of the week for any Julian or Gregorian calendar date. The input date must be in the format
+ * "MM-DD-YYYY" or "MM/DD/YYYY".
+ *
+ * <p>This class is final and cannot be instantiated.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Zeller%27s_congruence">Wikipedia: Zeller's Congruence</a>
+ */
+public final class ZellersCongruence {
+
+    private static final String[] DAYS = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
+
+    // Private constructor to prevent instantiation
+    private ZellersCongruence() {
+    }
+
+    /**
+     * Calculates the day of the week for a given date using Zeller's Congruence.
+     *
+     * <p>The algorithm works for both Julian and Gregorian calendar dates. The input date must be
+     * in the format "MM-DD-YYYY" or "MM/DD/YYYY".
+     *
+     * @param input the date in the format "MM-DD-YYYY" or "MM/DD/YYYY"
+     * @return a string indicating the day of the week for the given date
+     * @throws IllegalArgumentException if the input format is invalid, the date is invalid,
+     *                                  or the year is out of range
+     */
+    public static String calculateDay(String input) {
+        if (input == null || input.length() != 10) {
+            throw new IllegalArgumentException("Input date must be 10 characters long in the format MM-DD-YYYY or MM/DD/YYYY.");
+        }
+
+        int month = parsePart(input.substring(0, 2), 1, 12, "Month must be between 1 and 12.");
+        char sep1 = input.charAt(2);
+        validateSeparator(sep1);
+
+        int day = parsePart(input.substring(3, 5), 1, 31, "Day must be between 1 and 31.");
+        char sep2 = input.charAt(5);
+        validateSeparator(sep2);
+
+        int year = parsePart(input.substring(6, 10), 46, 8499, "Year must be between 46 and 8499.");
+
+        try {
+            Objects.requireNonNull(LocalDate.of(year, month, day));
+        } catch (DateTimeException e) {
+            throw new IllegalArgumentException("Invalid date.", e);
+        }
+        if (month <= 2) {
+            year -= 1;
+            month += 12;
+        }
+
+        int century = year / 100;
+        int yearOfCentury = year % 100;
+        int t = (int) (2.6 * month - 5.39);
+        int u = century / 4;
+        int v = yearOfCentury / 4;
+        int f = (int) Math.round((day + yearOfCentury + t + u + v - 2 * century) % 7.0);
+
+        int correctedDay = (f + 7) % 7;
+
+        return "The date " + input + " falls on a " + DAYS[correctedDay] + ".";
+    }
+
+    /**
+     * Parses a part of the date string and validates its range.
+     *
+     * @param part  the substring to parse
+     * @param min   the minimum valid value
+     * @param max   the maximum valid value
+     * @param error the error message to throw if validation fails
+     * @return the parsed integer value
+     * @throws IllegalArgumentException if the part is not a valid number or is out of range
+     */
+    private static int parsePart(String part, int min, int max, String error) {
+        try {
+            int value = Integer.parseInt(part);
+            if (value < min || value > max) {
+                throw new IllegalArgumentException(error);
+            }
+            return value;
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException("Invalid numeric part: " + part, e);
+        }
+    }
+
+    /**
+     * Validates the separator character in the date string.
+     *
+     * @param sep the separator character
+     * @throws IllegalArgumentException if the separator is not '-' or '/'
+     */
+    private static void validateSeparator(char sep) {
+        if (sep != '-' && sep != '/') {
+            throw new IllegalArgumentException("Date separator must be '-' or '/'.");
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/ZellersCongruenceTest.java b/src/test/java/com/thealgorithms/maths/ZellersCongruenceTest.java
new file mode 100644
index 000000000000..71bcbdc5ed9f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/ZellersCongruenceTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class ZellersCongruenceTest {
+
+    static Stream<Arguments> validDates() {
+        return Stream.of(Arguments.of("01-01-2000", "Saturday"), Arguments.of("12-25-2021", "Saturday"), Arguments.of("07-04-1776", "Thursday"), Arguments.of("02-29-2020", "Saturday"), Arguments.of("03-01-1900", "Thursday"), Arguments.of("03/01/1900", "Thursday"));
+    }
+
+    static Stream<Arguments> invalidDates() {
+        return Stream.of(Arguments.of("13-01-2000", "Month must be between 1 and 12."), Arguments.of("02-30-2020", "Invalid date."), Arguments.of("00-15-2020", "Month must be between 1 and 12."), Arguments.of("01-01-0000", "Year must be between 46 and 8499."),
+            Arguments.of("01/01/200", "Input date must be 10 characters long in the format MM-DD-YYYY or MM/DD/YYYY."), Arguments.of("01@01>2000", "Date separator must be '-' or '/'."), Arguments.of("aa-01-1900", "Invalid numeric part: aa"),
+            Arguments.of(null, "Input date must be 10 characters long in the format MM-DD-YYYY or MM/DD/YYYY."));
+    }
+
+    @ParameterizedTest
+    @MethodSource("validDates")
+    void testValidDates(String inputDate, String expectedDay) {
+        String result = ZellersCongruence.calculateDay(inputDate);
+        assertEquals("The date " + inputDate + " falls on a " + expectedDay + ".", result);
+    }
+
+    @ParameterizedTest
+    @MethodSource("invalidDates")
+    void testInvalidDates(String inputDate, String expectedErrorMessage) {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> ZellersCongruence.calculateDay(inputDate));
+        assertEquals(expectedErrorMessage, exception.getMessage());
+    }
+}

From c691b313f18b68d26da129a4d2993d5d9ec5a29a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 10 Oct 2025 10:32:20 +0200
Subject: [PATCH 0999/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 11.1.0 to 12.0.0 (#6719)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 11.1.0 to 12.0.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-11.1.0...checkstyle-12.0.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 12.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 938fb41088dc..be74291831d5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>11.1.0</version>
+                    <version>12.0.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 69d8406a6b93f15df6fb703b722e23a3ef7e9f5e Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 11 Oct 2025 00:47:53 +0300
Subject: [PATCH 1000/1338] chore(deps): bump
 org.apache.maven.plugins:maven-pmd-plugin from 3.27.0 to 3.28.0 (#6728)

chore(deps): bump org.apache.maven.plugins:maven-pmd-plugin

Bumps [org.apache.maven.plugins:maven-pmd-plugin](https://github.com/apache/maven-pmd-plugin) from 3.27.0 to 3.28.0.
- [Release notes](https://github.com/apache/maven-pmd-plugin/releases)
- [Commits](https://github.com/apache/maven-pmd-plugin/compare/maven-pmd-plugin-3.27.0...maven-pmd-plugin-3.28.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-pmd-plugin
  dependency-version: 3.28.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index be74291831d5..e0e3516c08eb 100644
--- a/pom.xml
+++ b/pom.xml
@@ -140,7 +140,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-pmd-plugin</artifactId>
-                <version>3.27.0</version>
+                <version>3.28.0</version>
                 <configuration>
                     <rulesets>
                         <ruleset>/rulesets/java/maven-pmd-plugin-default.xml</ruleset>

From f0fb971f35009b262d2df758b155069fe94036e1 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sat, 11 Oct 2025 18:45:18 +0530
Subject: [PATCH 1001/1338] refactor: Enhance docs, add tests in `PerlinNoise`
 (#6635)

* refactor: Enhance docs, add tests in `PerlinNoise`

* Fix lint

* Fix lint

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../com/thealgorithms/others/PerlinNoise.java | 144 +++++++++++++-----
 .../thealgorithms/others/PerlinNoiseTest.java | 103 +++++++++++++
 2 files changed, 206 insertions(+), 41 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/PerlinNoiseTest.java

diff --git a/src/main/java/com/thealgorithms/others/PerlinNoise.java b/src/main/java/com/thealgorithms/others/PerlinNoise.java
index e6551ed6b9ee..d97e3395ff18 100644
--- a/src/main/java/com/thealgorithms/others/PerlinNoise.java
+++ b/src/main/java/com/thealgorithms/others/PerlinNoise.java
@@ -4,99 +4,156 @@
 import java.util.Scanner;
 
 /**
- * For detailed info and implementation see: <a
- * href="http://devmag.org.za/2009/04/25/perlin-noise/">Perlin-Noise</a>
+ * Utility for generating 2D value-noise blended across octaves (commonly known
+ * as Perlin-like noise).
+ *
+ * <p>
+ * The implementation follows the classic approach of:
+ * <ol>
+ * <li>Generate a base grid of random values in [0, 1).</li>
+ * <li>For each octave k, compute a layer by bilinear interpolation of the base
+ * grid
+ * at period 2^k.</li>
+ * <li>Blend all layers from coarse to fine using a geometric series of
+ * amplitudes
+ * controlled by {@code persistence}, then normalize to [0, 1].</li>
+ * </ol>
+ *
+ * <p>
+ * For background see:
+ * <a href="http://devmag.org.za/2009/04/25/perlin-noise/">Perlin Noise</a>.
+ *
+ * <p>
+ * Constraints and notes:
+ * <ul>
+ * <li>{@code width} and {@code height} should be positive.</li>
+ * <li>{@code octaveCount} must be at least 1 (0 would lead to a division by
+ * zero).</li>
+ * <li>{@code persistence} should be in (0, 1], typical values around
+ * 0.5–0.8.</li>
+ * <li>Given the same seed and parameters, results are deterministic.</li>
+ * </ul>
  */
+
 public final class PerlinNoise {
     private PerlinNoise() {
     }
 
     /**
-     * @param width width of noise array
-     * @param height height of noise array
-     * @param octaveCount numbers of layers used for blending noise
-     * @param persistence value of impact each layer get while blending
-     * @param seed used for randomizer
-     * @return float array containing calculated "Perlin-Noise" values
+     * Generate a 2D array of blended noise values normalized to [0, 1].
+     *
+     * @param width       width of the noise array (columns)
+     * @param height      height of the noise array (rows)
+     * @param octaveCount number of octaves (layers) to blend; must be >= 1
+     * @param persistence per-octave amplitude multiplier in (0, 1]
+     * @param seed        seed for the random base grid
+     * @return a {@code width x height} array containing blended noise values in [0,
+     *         1]
      */
     static float[][] generatePerlinNoise(int width, int height, int octaveCount, float persistence, long seed) {
-        final float[][] base = new float[width][height];
-        final float[][] perlinNoise = new float[width][height];
-        final float[][][] noiseLayers = new float[octaveCount][][];
+        if (width <= 0 || height <= 0) {
+            throw new IllegalArgumentException("width and height must be > 0");
+        }
 
+        if (octaveCount < 1) {
+            throw new IllegalArgumentException("octaveCount must be >= 1");
+        }
+        if (!(persistence > 0f && persistence <= 1f)) { // using > to exclude 0 and NaN
+            throw new IllegalArgumentException("persistence must be in (0, 1]");
+        }
+        final float[][] base = createBaseGrid(width, height, seed);
+        final float[][][] layers = createLayers(base, width, height, octaveCount);
+        return blendAndNormalize(layers, width, height, persistence);
+    }
+
+    /** Create the base random lattice values in [0,1). */
+    static float[][] createBaseGrid(int width, int height, long seed) {
+        final float[][] base = new float[width][height];
         Random random = new Random(seed);
-        // fill base array with random values as base for noise
         for (int x = 0; x < width; x++) {
             for (int y = 0; y < height; y++) {
                 base[x][y] = random.nextFloat();
             }
         }
+        return base;
+    }
 
-        // calculate octaves with different roughness
+    /** Pre-compute each octave layer at increasing frequency. */
+    static float[][][] createLayers(float[][] base, int width, int height, int octaveCount) {
+        final float[][][] noiseLayers = new float[octaveCount][][];
         for (int octave = 0; octave < octaveCount; octave++) {
             noiseLayers[octave] = generatePerlinNoiseLayer(base, width, height, octave);
         }
+        return noiseLayers;
+    }
 
+    /** Blend layers using geometric amplitudes and normalize to [0,1]. */
+    static float[][] blendAndNormalize(float[][][] layers, int width, int height, float persistence) {
+        final int octaveCount = layers.length;
+        final float[][] out = new float[width][height];
         float amplitude = 1f;
         float totalAmplitude = 0f;
 
-        // calculate perlin noise by blending each layer together with specific persistence
         for (int octave = octaveCount - 1; octave >= 0; octave--) {
             amplitude *= persistence;
             totalAmplitude += amplitude;
-
+            final float[][] layer = layers[octave];
             for (int x = 0; x < width; x++) {
                 for (int y = 0; y < height; y++) {
-                    // adding each value of the noise layer to the noise
-                    // by increasing amplitude the rougher noises will have more impact
-                    perlinNoise[x][y] += noiseLayers[octave][x][y] * amplitude;
+                    out[x][y] += layer[x][y] * amplitude;
                 }
             }
         }
 
-        // normalize values so that they stay between 0..1
+        if (totalAmplitude <= 0f || Float.isInfinite(totalAmplitude) || Float.isNaN(totalAmplitude)) {
+            throw new IllegalStateException("Invalid totalAmplitude computed during normalization");
+        }
+
+        final float invTotal = 1f / totalAmplitude;
         for (int x = 0; x < width; x++) {
             for (int y = 0; y < height; y++) {
-                perlinNoise[x][y] /= totalAmplitude;
+                out[x][y] *= invTotal;
             }
         }
-
-        return perlinNoise;
+        return out;
     }
 
     /**
-     * @param base base random float array
-     * @param width width of noise array
+     * Generate a single octave layer by bilinear interpolation of a base grid at a
+     * given octave (period = 2^octave).
+     *
+     * @param base   base random float array of size {@code width x height}
+     * @param width  width of noise array
      * @param height height of noise array
-     * @param octave current layer
-     * @return float array containing calculated "Perlin-Noise-Layer" values
+     * @param octave current octave (0 for period 1, 1 for period 2, ...)
+     * @return float array containing the octave's interpolated values
      */
     static float[][] generatePerlinNoiseLayer(float[][] base, int width, int height, int octave) {
         float[][] perlinNoiseLayer = new float[width][height];
 
-        // calculate period (wavelength) for different shapes
+        // Calculate period (wavelength) for different shapes.
         int period = 1 << octave; // 2^k
         float frequency = 1f / period; // 1/2^k
 
         for (int x = 0; x < width; x++) {
-            // calculates the horizontal sampling indices
+            // Calculate the horizontal sampling indices.
             int x0 = (x / period) * period;
             int x1 = (x0 + period) % width;
-            float horizintalBlend = (x - x0) * frequency;
+            float horizontalBlend = (x - x0) * frequency;
 
             for (int y = 0; y < height; y++) {
-                // calculates the vertical sampling indices
+                // Calculate the vertical sampling indices.
                 int y0 = (y / period) * period;
                 int y1 = (y0 + period) % height;
                 float verticalBlend = (y - y0) * frequency;
 
-                // blend top corners
-                float top = interpolate(base[x0][y0], base[x1][y0], horizintalBlend);
+                // Blend top corners.
+                float top = interpolate(base[x0][y0], base[x1][y0], horizontalBlend);
 
-                // blend bottom corners
-                float bottom = interpolate(base[x0][y1], base[x1][y1], horizintalBlend);
+                // Blend bottom corners.
+                float bottom = interpolate(base[x0][y1], base[x1][y1], horizontalBlend);
 
-                // blend top and bottom interpolation to get the final blend value for this cell
+                // Blend top and bottom interpolation to get the final value for this cell.
                 perlinNoiseLayer[x][y] = interpolate(top, bottom, verticalBlend);
             }
         }
@@ -105,16 +162,21 @@ static float[][] generatePerlinNoiseLayer(float[][] base, int width, int height,
     }
 
     /**
-     * @param a value of point a
-     * @param b value of point b
-     * @param alpha determine which value has more impact (closer to 0 -> a,
-     * closer to 1 -> b)
-     * @return interpolated value
+     * Linear interpolation between two values.
+     *
+     * @param a     value at alpha = 0
+     * @param b     value at alpha = 1
+     * @param alpha interpolation factor in [0, 1]
+     * @return interpolated value {@code (1 - alpha) * a + alpha * b}
      */
     static float interpolate(float a, float b, float alpha) {
         return a * (1 - alpha) + alpha * b;
     }
 
+    /**
+     * Small demo that prints a text representation of the noise using a provided
+     * character set.
+     */
     public static void main(String[] args) {
         Scanner in = new Scanner(System.in);
 
@@ -148,7 +210,7 @@ public static void main(String[] args) {
         final char[] chars = charset.toCharArray();
         final int length = chars.length;
         final float step = 1f / length;
-        // output based on charset
+        // Output based on charset thresholds.
         for (int x = 0; x < width; x++) {
             for (int y = 0; y < height; y++) {
                 float value = step;
diff --git a/src/test/java/com/thealgorithms/others/PerlinNoiseTest.java b/src/test/java/com/thealgorithms/others/PerlinNoiseTest.java
new file mode 100644
index 000000000000..88c043ad9aa3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/PerlinNoiseTest.java
@@ -0,0 +1,103 @@
+package com.thealgorithms.others;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class PerlinNoiseTest {
+
+    @Test
+    @DisplayName("generatePerlinNoise returns array with correct dimensions")
+    void testDimensions() {
+        int w = 8;
+        int h = 6;
+        float[][] noise = PerlinNoise.generatePerlinNoise(w, h, 4, 0.6f, 123L);
+        assertThat(noise).hasDimensions(w, h);
+    }
+
+    @Test
+    @DisplayName("All values are within [0,1] after normalization")
+    void testRange() {
+        int w = 16;
+        int h = 16;
+        float[][] noise = PerlinNoise.generatePerlinNoise(w, h, 5, 0.7f, 42L);
+        for (int x = 0; x < w; x++) {
+            for (int y = 0; y < h; y++) {
+                assertThat(noise[x][y]).isBetween(0f, 1f);
+            }
+        }
+    }
+
+    @Test
+    @DisplayName("Deterministic for same parameters and seed")
+    void testDeterminism() {
+        int w = 10;
+        int h = 10;
+        long seed = 98765L;
+        float[][] a = PerlinNoise.generatePerlinNoise(w, h, 3, 0.5f, seed);
+        float[][] b = PerlinNoise.generatePerlinNoise(w, h, 3, 0.5f, seed);
+        for (int x = 0; x < w; x++) {
+            for (int y = 0; y < h; y++) {
+                assertThat(a[x][y]).isEqualTo(b[x][y]);
+            }
+        }
+    }
+
+    @Test
+    @DisplayName("Different seeds produce different outputs (probabilistically)")
+    void testDifferentSeeds() {
+        int w = 12;
+        int h = 12;
+        float[][] a = PerlinNoise.generatePerlinNoise(w, h, 4, 0.8f, 1L);
+        float[][] b = PerlinNoise.generatePerlinNoise(w, h, 4, 0.8f, 2L);
+
+        // Count exact equalities; expect very few or none.
+        int equalCount = 0;
+        for (int x = 0; x < w; x++) {
+            for (int y = 0; y < h; y++) {
+                if (Float.compare(a[x][y], b[x][y]) == 0) {
+                    equalCount++;
+                }
+            }
+        }
+        assertThat(equalCount).isLessThan(w * h / 10); // less than 10% equal exact values
+    }
+
+    @Test
+    @DisplayName("Interpolation endpoints are respected")
+    void testInterpolateEndpoints() {
+        assertThat(PerlinNoise.interpolate(0f, 1f, 0f)).isEqualTo(0f);
+        assertThat(PerlinNoise.interpolate(0f, 1f, 1f)).isEqualTo(1f);
+        assertThat(PerlinNoise.interpolate(0.2f, 0.8f, 0.5f)).isEqualTo(0.5f);
+    }
+
+    @Test
+    @DisplayName("Single octave reduces to bilinear interpolation of base grid")
+    void testSingleOctaveLayer() {
+        int w = 8;
+        int h = 8;
+        long seed = 7L;
+        float[][] base = PerlinNoise.createBaseGrid(w, h, seed);
+        float[][] layer = PerlinNoise.generatePerlinNoiseLayer(base, w, h, 0); // period=1
+        // With period = 1, x0=x, x1=(x+1)%w etc. Values should be smooth and within
+        // [0,1]
+        for (int x = 0; x < w; x++) {
+            for (int y = 0; y < h; y++) {
+                assertThat(layer[x][y]).isBetween(0f, 1f);
+            }
+        }
+    }
+
+    @Test
+    @DisplayName("Invalid inputs are rejected")
+    void testInvalidInputs() {
+        assertThatThrownBy(() -> PerlinNoise.generatePerlinNoise(0, 5, 1, 0.5f, 1L)).isInstanceOf(IllegalArgumentException.class);
+        assertThatThrownBy(() -> PerlinNoise.generatePerlinNoise(5, -1, 1, 0.5f, 1L)).isInstanceOf(IllegalArgumentException.class);
+        assertThatThrownBy(() -> PerlinNoise.generatePerlinNoise(5, 5, 0, 0.5f, 1L)).isInstanceOf(IllegalArgumentException.class);
+        assertThatThrownBy(() -> PerlinNoise.generatePerlinNoise(5, 5, 1, 0f, 1L)).isInstanceOf(IllegalArgumentException.class);
+        assertThatThrownBy(() -> PerlinNoise.generatePerlinNoise(5, 5, 1, Float.NaN, 1L)).isInstanceOf(IllegalArgumentException.class);
+        assertThatThrownBy(() -> PerlinNoise.generatePerlinNoise(5, 5, 1, 1.1f, 1L)).isInstanceOf(IllegalArgumentException.class);
+    }
+}

From 2a004a0141156bbb1cecfffa7708377bc6baad5f Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 12 Oct 2025 11:07:53 +0530
Subject: [PATCH 1002/1338] refactor: Enhance docs, code, add tests in
 `InsertDeleteInArray` (#6647)

---
 .../others/InsertDeleteInArray.java           | 189 ++++++++++++---
 .../others/InsertDeleteInArrayTest.java       | 220 ++++++++++++++++++
 2 files changed, 375 insertions(+), 34 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/InsertDeleteInArrayTest.java

diff --git a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
index 15093549871b..06a2539ee8b7 100644
--- a/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
+++ b/src/main/java/com/thealgorithms/others/InsertDeleteInArray.java
@@ -1,51 +1,172 @@
 package com.thealgorithms.others;
 
+import java.util.Arrays;
 import java.util.Scanner;
 
+/**
+ * Utility class for performing insert and delete operations on arrays.
+ * <p>
+ * This class demonstrates how to insert an element at a specific position and
+ * delete an element from a specific position in an integer array. Since arrays
+ * in Java have fixed size, insertion creates a new array with increased size,
+ * and deletion shifts elements to fill the gap.
+ * </p>
+ *
+ * <p>
+ * <strong>Time Complexity:</strong>
+ * </p>
+ * <ul>
+ * <li>Insert: O(n) - requires copying elements to new array</li>
+ * <li>Delete: O(n) - requires shifting elements</li>
+ * </ul>
+ *
+ * <p>
+ * <strong>Space Complexity:</strong>
+ * </p>
+ * <ul>
+ * <li>Insert: O(n) - new array of size n+1</li>
+ * <li>Delete: O(1) - in-place modification (excluding result array)</li>
+ * </ul>
+ *
+ * @author TheAlgorithms community
+ * @see <a href="https://en.wikipedia.org/wiki/Array_(data_structure)">Array
+ *      Data Structure</a>
+ */
 public final class InsertDeleteInArray {
     private InsertDeleteInArray() {
     }
 
+    /**
+     * Inserts an element at the specified position in the array.
+     * <p>
+     * Creates a new array with size = original array size + 1.
+     * Elements at positions &lt;= insertPos retain their positions,
+     * while elements at positions &gt; insertPos are shifted right by one position.
+     * </p>
+     *
+     * @param array    the original array
+     * @param element  the element to be inserted
+     * @param position the index at which the element should be inserted (0-based)
+     * @return a new array with the element inserted at the specified position
+     * @throws IllegalArgumentException if position is negative or greater than
+     *                                  array length
+     * @throws IllegalArgumentException if array is null
+     */
+    public static int[] insertElement(int[] array, int element, int position) {
+        if (array == null) {
+            throw new IllegalArgumentException("Array cannot be null");
+        }
+        if (position < 0 || position > array.length) {
+            throw new IllegalArgumentException("Position must be between 0 and " + array.length);
+        }
+
+        int[] newArray = new int[array.length + 1];
+
+        // Copy elements before insertion position
+        System.arraycopy(array, 0, newArray, 0, position);
+
+        // Insert the new element
+        newArray[position] = element;
+
+        // Copy remaining elements after insertion position
+        System.arraycopy(array, position, newArray, position + 1, array.length - position);
+
+        return newArray;
+    }
+
+    /**
+     * Deletes an element at the specified position from the array.
+     * <p>
+     * Creates a new array with size = original array size - 1.
+     * Elements after the deletion position are shifted left by one position.
+     * </p>
+     *
+     * @param array    the original array
+     * @param position the index of the element to be deleted (0-based)
+     * @return a new array with the element at the specified position removed
+     * @throws IllegalArgumentException if position is negative or greater than or
+     *                                  equal to array length
+     * @throws IllegalArgumentException if array is null or empty
+     */
+    public static int[] deleteElement(int[] array, int position) {
+        if (array == null) {
+            throw new IllegalArgumentException("Array cannot be null");
+        }
+        if (array.length == 0) {
+            throw new IllegalArgumentException("Array is empty");
+        }
+        if (position < 0 || position >= array.length) {
+            throw new IllegalArgumentException("Position must be between 0 and " + (array.length - 1));
+        }
+
+        int[] newArray = new int[array.length - 1];
+
+        // Copy elements before deletion position
+        System.arraycopy(array, 0, newArray, 0, position);
+
+        // Copy elements after deletion position
+        System.arraycopy(array, position + 1, newArray, position, array.length - position - 1);
+
+        return newArray;
+    }
+
+    /**
+     * Main method demonstrating insert and delete operations on an array.
+     * <p>
+     * This method interactively:
+     * <ol>
+     * <li>Takes array size and elements as input</li>
+     * <li>Inserts a new element at a specified position</li>
+     * <li>Deletes an element from a specified position</li>
+     * <li>Displays the array after each operation</li>
+     * </ol>
+     * </p>
+     *
+     * @param args command line arguments (not used)
+     */
     public static void main(String[] args) {
-        try (Scanner s = new Scanner(System.in)) {
-            System.out.println("Enter the size of the array");
-            int size = s.nextInt();
-            int[] a = new int[size];
-            int i;
-
-            // To enter the initial elements
-            for (i = 0; i < size; i++) {
-                System.out.println("Enter the element");
-                a[i] = s.nextInt();
-            }
+        try (Scanner scanner = new Scanner(System.in)) {
+            // Input: array size and elements
+            System.out.println("Enter the size of the array:");
+            int size = scanner.nextInt();
 
-            // To insert a new element(we are creating a new array)
-            System.out.println("Enter the index at which the element should be inserted");
-            int insertPos = s.nextInt();
-            System.out.println("Enter the element to be inserted");
-            int ins = s.nextInt();
-            int size2 = size + 1;
-            int[] b = new int[size2];
-            for (i = 0; i < size2; i++) {
-                if (i <= insertPos) {
-                    b[i] = a[i];
-                } else {
-                    b[i] = a[i - 1];
-                }
+            if (size <= 0) {
+                System.out.println("Array size must be positive");
+                return;
             }
-            b[insertPos] = ins;
-            for (i = 0; i < size2; i++) {
-                System.out.println(b[i]);
+
+            int[] array = new int[size];
+
+            System.out.println("Enter " + size + " elements:");
+            for (int i = 0; i < size; i++) {
+                array[i] = scanner.nextInt();
             }
 
-            // To delete an element given the index
-            System.out.println("Enter the index at which element is to be deleted");
-            int delPos = s.nextInt();
-            for (i = delPos; i < size2 - 1; i++) {
-                b[i] = b[i + 1];
+            System.out.println("Original array: " + Arrays.toString(array));
+
+            // Insert operation
+            System.out.println("\nEnter the index at which the element should be inserted (0-" + size + "):");
+            int insertPos = scanner.nextInt();
+            System.out.println("Enter the element to be inserted:");
+            int elementToInsert = scanner.nextInt();
+
+            try {
+                array = insertElement(array, elementToInsert, insertPos);
+                System.out.println("Array after insertion: " + Arrays.toString(array));
+            } catch (IllegalArgumentException e) {
+                System.out.println("Error during insertion: " + e.getMessage());
+                return;
             }
-            for (i = 0; i < size2 - 1; i++) {
-                System.out.println(b[i]);
+
+            // Delete operation
+            System.out.println("\nEnter the index at which element is to be deleted (0-" + (array.length - 1) + "):");
+            int deletePos = scanner.nextInt();
+
+            try {
+                array = deleteElement(array, deletePos);
+                System.out.println("Array after deletion: " + Arrays.toString(array));
+            } catch (IllegalArgumentException e) {
+                System.out.println("Error during deletion: " + e.getMessage());
             }
         }
     }
diff --git a/src/test/java/com/thealgorithms/others/InsertDeleteInArrayTest.java b/src/test/java/com/thealgorithms/others/InsertDeleteInArrayTest.java
new file mode 100644
index 000000000000..e8e49980de13
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/InsertDeleteInArrayTest.java
@@ -0,0 +1,220 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test cases for {@link InsertDeleteInArray} class.
+ * <p>
+ * Tests cover:
+ * <ul>
+ * <li>Insert operations at various positions</li>
+ * <li>Delete operations at various positions</li>
+ * <li>Edge cases (empty arrays, single element, boundary positions)</li>
+ * <li>Error conditions (null arrays, invalid positions)</li>
+ * </ul>
+ * </p>
+ */
+class InsertDeleteInArrayTest {
+
+    // ========== Insert Element Tests ==========
+
+    @Test
+    void testInsertAtBeginning() {
+        int[] array = {2, 3, 4, 5};
+        int[] result = InsertDeleteInArray.insertElement(array, 1, 0);
+        assertArrayEquals(new int[] {1, 2, 3, 4, 5}, result);
+    }
+
+    @Test
+    void testInsertAtEnd() {
+        int[] array = {1, 2, 3, 4};
+        int[] result = InsertDeleteInArray.insertElement(array, 5, 4);
+        assertArrayEquals(new int[] {1, 2, 3, 4, 5}, result);
+    }
+
+    @Test
+    void testInsertInMiddle() {
+        int[] array = {1, 2, 4, 5};
+        int[] result = InsertDeleteInArray.insertElement(array, 3, 2);
+        assertArrayEquals(new int[] {1, 2, 3, 4, 5}, result);
+    }
+
+    @Test
+    void testInsertIntoEmptyArray() {
+        int[] array = {};
+        int[] result = InsertDeleteInArray.insertElement(array, 42, 0);
+        assertArrayEquals(new int[] {42}, result);
+    }
+
+    @Test
+    void testInsertIntoSingleElementArray() {
+        int[] array = {5};
+        int[] result = InsertDeleteInArray.insertElement(array, 3, 0);
+        assertArrayEquals(new int[] {3, 5}, result);
+    }
+
+    @Test
+    void testInsertNegativeNumber() {
+        int[] array = {1, 2, 3};
+        int[] result = InsertDeleteInArray.insertElement(array, -10, 1);
+        assertArrayEquals(new int[] {1, -10, 2, 3}, result);
+    }
+
+    @Test
+    void testInsertZero() {
+        int[] array = {1, 2, 3};
+        int[] result = InsertDeleteInArray.insertElement(array, 0, 1);
+        assertArrayEquals(new int[] {1, 0, 2, 3}, result);
+    }
+
+    @Test
+    void testInsertWithNullArray() {
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> InsertDeleteInArray.insertElement(null, 5, 0));
+        assertEquals("Array cannot be null", exception.getMessage());
+    }
+
+    @Test
+    void testInsertWithNegativePosition() {
+        int[] array = {1, 2, 3};
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> InsertDeleteInArray.insertElement(array, 5, -1));
+        assertEquals("Position must be between 0 and 3", exception.getMessage());
+    }
+
+    @Test
+    void testInsertWithPositionTooLarge() {
+        int[] array = {1, 2, 3};
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> InsertDeleteInArray.insertElement(array, 5, 4));
+        assertEquals("Position must be between 0 and 3", exception.getMessage());
+    }
+
+    // ========== Delete Element Tests ==========
+
+    @Test
+    void testDeleteFromBeginning() {
+        int[] array = {1, 2, 3, 4, 5};
+        int[] result = InsertDeleteInArray.deleteElement(array, 0);
+        assertArrayEquals(new int[] {2, 3, 4, 5}, result);
+    }
+
+    @Test
+    void testDeleteFromEnd() {
+        int[] array = {1, 2, 3, 4, 5};
+        int[] result = InsertDeleteInArray.deleteElement(array, 4);
+        assertArrayEquals(new int[] {1, 2, 3, 4}, result);
+    }
+
+    @Test
+    void testDeleteFromMiddle() {
+        int[] array = {1, 2, 3, 4, 5};
+        int[] result = InsertDeleteInArray.deleteElement(array, 2);
+        assertArrayEquals(new int[] {1, 2, 4, 5}, result);
+    }
+
+    @Test
+    void testDeleteFromSingleElementArray() {
+        int[] array = {42};
+        int[] result = InsertDeleteInArray.deleteElement(array, 0);
+        assertArrayEquals(new int[] {}, result);
+    }
+
+    @Test
+    void testDeleteFromTwoElementArray() {
+        int[] array = {10, 20};
+        int[] result = InsertDeleteInArray.deleteElement(array, 1);
+        assertArrayEquals(new int[] {10}, result);
+    }
+
+    @Test
+    void testDeleteWithNullArray() {
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> InsertDeleteInArray.deleteElement(null, 0));
+        assertEquals("Array cannot be null", exception.getMessage());
+    }
+
+    @Test
+    void testDeleteFromEmptyArray() {
+        int[] array = {};
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> InsertDeleteInArray.deleteElement(array, 0));
+        assertEquals("Array is empty", exception.getMessage());
+    }
+
+    @Test
+    void testDeleteWithNegativePosition() {
+        int[] array = {1, 2, 3};
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> InsertDeleteInArray.deleteElement(array, -1));
+        assertEquals("Position must be between 0 and 2", exception.getMessage());
+    }
+
+    @Test
+    void testDeleteWithPositionTooLarge() {
+        int[] array = {1, 2, 3};
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> InsertDeleteInArray.deleteElement(array, 3));
+        assertEquals("Position must be between 0 and 2", exception.getMessage());
+    }
+
+    @Test
+    void testDeleteWithPositionEqualToLength() {
+        int[] array = {1, 2, 3, 4, 5};
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> InsertDeleteInArray.deleteElement(array, 5));
+        assertEquals("Position must be between 0 and 4", exception.getMessage());
+    }
+
+    // ========== Combined Operations Tests ==========
+
+    @Test
+    void testInsertThenDelete() {
+        int[] array = {1, 2, 3};
+        int[] afterInsert = InsertDeleteInArray.insertElement(array, 99, 1);
+        assertArrayEquals(new int[] {1, 99, 2, 3}, afterInsert);
+        int[] afterDelete = InsertDeleteInArray.deleteElement(afterInsert, 1);
+        assertArrayEquals(new int[] {1, 2, 3}, afterDelete);
+    }
+
+    @Test
+    void testMultipleInsertions() {
+        int[] array = {1, 3, 5};
+        array = InsertDeleteInArray.insertElement(array, 2, 1);
+        assertArrayEquals(new int[] {1, 2, 3, 5}, array);
+        array = InsertDeleteInArray.insertElement(array, 4, 3);
+        assertArrayEquals(new int[] {1, 2, 3, 4, 5}, array);
+    }
+
+    @Test
+    void testMultipleDeletions() {
+        int[] array = {1, 2, 3, 4, 5};
+        array = InsertDeleteInArray.deleteElement(array, 2);
+        assertArrayEquals(new int[] {1, 2, 4, 5}, array);
+        array = InsertDeleteInArray.deleteElement(array, 0);
+        assertArrayEquals(new int[] {2, 4, 5}, array);
+    }
+
+    @Test
+    void testLargeArray() {
+        int[] array = new int[100];
+        for (int i = 0; i < 100; i++) {
+            array[i] = i;
+        }
+        int[] result = InsertDeleteInArray.insertElement(array, 999, 50);
+        assertEquals(101, result.length);
+        assertEquals(999, result[50]);
+        assertEquals(49, result[49]);
+        assertEquals(50, result[51]);
+    }
+
+    @Test
+    void testArrayWithDuplicates() {
+        int[] array = {1, 2, 2, 3, 2};
+        int[] result = InsertDeleteInArray.deleteElement(array, 1);
+        assertArrayEquals(new int[] {1, 2, 3, 2}, result);
+    }
+
+    @Test
+    void testNegativeNumbers() {
+        int[] array = {-5, -3, -1, 0, 1};
+        int[] result = InsertDeleteInArray.insertElement(array, -2, 2);
+        assertArrayEquals(new int[] {-5, -3, -2, -1, 0, 1}, result);
+    }
+}

From b5246c3d868738d7e17f7f2f0c8730ab354f07b4 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 12 Oct 2025 11:20:58 +0530
Subject: [PATCH 1003/1338] refactor: Enhance docs, code, add tests in
 `Huffman` (#6646)

* refactor: Enhance docs, code, add tests in `Huffman`

* Fix lint

* Fix lint
---
 .../com/thealgorithms/others/Huffman.java     | 252 ++++++++++++------
 .../com/thealgorithms/others/HuffmanTest.java | 223 ++++++++++++++++
 2 files changed, 392 insertions(+), 83 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/HuffmanTest.java

diff --git a/src/main/java/com/thealgorithms/others/Huffman.java b/src/main/java/com/thealgorithms/others/Huffman.java
index 4fdee5d5e70e..22e75da502b5 100644
--- a/src/main/java/com/thealgorithms/others/Huffman.java
+++ b/src/main/java/com/thealgorithms/others/Huffman.java
@@ -1,125 +1,211 @@
 package com.thealgorithms.others;
 
 import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.PriorityQueue;
-import java.util.Scanner;
 
-// node class is the basic structure
-// of each node present in the Huffman - tree.
+/**
+ * Node class representing a node in the Huffman tree.
+ * Each node contains a character, its frequency, and references to left and
+ * right children.
+ */
 class HuffmanNode {
-
     int data;
     char c;
-
     HuffmanNode left;
     HuffmanNode right;
-}
 
-// comparator class helps to compare the node
-// on the basis of one of its attribute.
-// Here we will be compared
-// on the basis of data values of the nodes.
-class MyComparator implements Comparator<HuffmanNode> {
+    /**
+     * Constructor for HuffmanNode.
+     *
+     * @param c    the character stored in this node
+     * @param data the frequency of the character
+     */
+    HuffmanNode(char c, int data) {
+        this.c = c;
+        this.data = data;
+        this.left = null;
+        this.right = null;
+    }
+
+    /**
+     * Default constructor for HuffmanNode.
+     */
+    HuffmanNode() {
+        this.left = null;
+        this.right = null;
+    }
+}
 
+/**
+ * Comparator class for comparing HuffmanNode objects based on their frequency
+ * data.
+ * Used to maintain min-heap property in the priority queue.
+ */
+class HuffmanComparator implements Comparator<HuffmanNode> {
+    @Override
     public int compare(HuffmanNode x, HuffmanNode y) {
-        return x.data - y.data;
+        return Integer.compare(x.data, y.data);
     }
 }
 
+/**
+ * Implementation of Huffman Coding algorithm for data compression.
+ * Huffman Coding is a greedy algorithm that assigns variable-length codes to
+ * characters
+ * based on their frequency of occurrence. Characters with higher frequency get
+ * shorter codes.
+ *
+ * <p>
+ * Time Complexity: O(n log n) where n is the number of unique characters
+ * Space Complexity: O(n)
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Huffman_coding">Huffman
+ *      Coding</a>
+ */
 public final class Huffman {
     private Huffman() {
     }
 
-    // recursive function to print the
-    // huffman-code through the tree traversal.
-    // Here s is the huffman - code generated.
-    public static void printCode(HuffmanNode root, String s) {
-        // base case; if the left and right are null
-        // then its a leaf node and we print
-        // the code s generated by traversing the tree.
-        if (root.left == null && root.right == null && Character.isLetter(root.c)) {
-            // c is the character in the node
-            System.out.println(root.c + ":" + s);
-
-            return;
+    /**
+     * Builds a Huffman tree from the given character array and their frequencies.
+     *
+     * @param charArray array of characters
+     * @param charFreq  array of frequencies corresponding to the characters
+     * @return root node of the Huffman tree
+     * @throws IllegalArgumentException if arrays are null, empty, or have different
+     *                                  lengths
+     */
+    public static HuffmanNode buildHuffmanTree(char[] charArray, int[] charFreq) {
+        if (charArray == null || charFreq == null) {
+            throw new IllegalArgumentException("Character array and frequency array cannot be null");
+        }
+        if (charArray.length == 0 || charFreq.length == 0) {
+            throw new IllegalArgumentException("Character array and frequency array cannot be empty");
+        }
+        if (charArray.length != charFreq.length) {
+            throw new IllegalArgumentException("Character array and frequency array must have the same length");
         }
 
-        // if we go to left then add "0" to the code.
-        // if we go to the right add"1" to the code.
-        // recursive calls for left and
-        // right sub-tree of the generated tree.
-        printCode(root.left, s + "0");
-        printCode(root.right, s + "1");
-    }
+        int n = charArray.length;
+        PriorityQueue<HuffmanNode> priorityQueue = new PriorityQueue<>(n, new HuffmanComparator());
 
-    // main function
-    public static void main(String[] args) {
-        Scanner s = new Scanner(System.in);
+        // Create leaf nodes and add to priority queue
+        for (int i = 0; i < n; i++) {
+            if (charFreq[i] < 0) {
+                throw new IllegalArgumentException("Frequencies must be non-negative");
+            }
+            HuffmanNode node = new HuffmanNode(charArray[i], charFreq[i]);
+            priorityQueue.add(node);
+        }
 
-        // number of characters.
-        int n = 6;
-        char[] charArray = {'a', 'b', 'c', 'd', 'e', 'f'};
-        int[] charfreq = {5, 9, 12, 13, 16, 45};
+        // Build the Huffman tree
+        while (priorityQueue.size() > 1) {
+            HuffmanNode left = priorityQueue.poll();
+            HuffmanNode right = priorityQueue.poll();
 
-        // creating a priority queue q.
-        // makes a min-priority queue(min-heap).
-        PriorityQueue<HuffmanNode> q = new PriorityQueue<HuffmanNode>(n, new MyComparator());
+            HuffmanNode parent = new HuffmanNode();
+            parent.data = left.data + right.data;
+            parent.c = '-';
+            parent.left = left;
+            parent.right = right;
 
-        for (int i = 0; i < n; i++) {
-            // creating a Huffman node object
-            // and add it to the priority queue.
-            HuffmanNode hn = new HuffmanNode();
+            priorityQueue.add(parent);
+        }
 
-            hn.c = charArray[i];
-            hn.data = charfreq[i];
+        return priorityQueue.poll();
+    }
 
-            hn.left = null;
-            hn.right = null;
+    /**
+     * Generates Huffman codes for all characters in the tree.
+     *
+     * @param root root node of the Huffman tree
+     * @return map of characters to their Huffman codes
+     */
+    public static Map<Character, String> generateCodes(HuffmanNode root) {
+        Map<Character, String> huffmanCodes = new HashMap<>();
+        if (root != null) {
+            generateCodesHelper(root, "", huffmanCodes);
+        }
+        return huffmanCodes;
+    }
 
-            // add functions adds
-            // the huffman node to the queue.
-            q.add(hn);
+    /**
+     * Helper method to recursively generate Huffman codes by traversing the tree.
+     *
+     * @param node         current node in the tree
+     * @param code         current code being built
+     * @param huffmanCodes map to store character-to-code mappings
+     */
+    private static void generateCodesHelper(HuffmanNode node, String code, Map<Character, String> huffmanCodes) {
+        if (node == null) {
+            return;
         }
 
-        // create a root node
-        HuffmanNode root = null;
+        // If it's a leaf node, store the code
+        if (node.left == null && node.right == null && Character.isLetter(node.c)) {
+            huffmanCodes.put(node.c, code.isEmpty() ? "0" : code);
+            return;
+        }
 
-        // Here we will extract the two minimum value
-        // from the heap each time until
-        // its size reduces to 1, extract until
-        // all the nodes are extracted.
-        while (q.size() > 1) {
-            // first min extract.
-            HuffmanNode x = q.peek();
-            q.poll();
+        // Traverse left with '0' and right with '1'
+        if (node.left != null) {
+            generateCodesHelper(node.left, code + "0", huffmanCodes);
+        }
+        if (node.right != null) {
+            generateCodesHelper(node.right, code + "1", huffmanCodes);
+        }
+    }
 
-            // second min extarct.
-            HuffmanNode y = q.peek();
-            q.poll();
+    /**
+     * Prints Huffman codes for all characters in the tree.
+     * This method is kept for backward compatibility and demonstration purposes.
+     *
+     * @param root root node of the Huffman tree
+     * @param code current code being built (initially empty string)
+     */
+    public static void printCode(HuffmanNode root, String code) {
+        if (root == null) {
+            return;
+        }
 
-            // new node f which is equal
-            HuffmanNode f = new HuffmanNode();
+        // If it's a leaf node, print the code
+        if (root.left == null && root.right == null && Character.isLetter(root.c)) {
+            System.out.println(root.c + ":" + code);
+            return;
+        }
 
-            // to the sum of the frequency of the two nodes
-            // assigning values to the f node.
-            f.data = x.data + y.data;
-            f.c = '-';
+        // Traverse left with '0' and right with '1'
+        if (root.left != null) {
+            printCode(root.left, code + "0");
+        }
+        if (root.right != null) {
+            printCode(root.right, code + "1");
+        }
+    }
 
-            // first extracted node as left child.
-            f.left = x;
+    /**
+     * Demonstrates the Huffman coding algorithm with sample data.
+     *
+     * @param args command line arguments (not used)
+     */
+    public static void main(String[] args) {
+        // Sample characters and their frequencies
+        char[] charArray = {'a', 'b', 'c', 'd', 'e', 'f'};
+        int[] charFreq = {5, 9, 12, 13, 16, 45};
 
-            // second extracted node as the right child.
-            f.right = y;
+        System.out.println("Characters: a, b, c, d, e, f");
+        System.out.println("Frequencies: 5, 9, 12, 13, 16, 45");
+        System.out.println("\nHuffman Codes:");
 
-            // marking the f node as the root node.
-            root = f;
+        // Build Huffman tree
+        HuffmanNode root = buildHuffmanTree(charArray, charFreq);
 
-            // add this node to the priority-queue.
-            q.add(f);
+        // Generate and print Huffman codes
+        Map<Character, String> codes = generateCodes(root);
+        for (Map.Entry<Character, String> entry : codes.entrySet()) {
+            System.out.println(entry.getKey() + ": " + entry.getValue());
         }
-
-        // print the codes by traversing the tree
-        printCode(root, "");
-        s.close();
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/HuffmanTest.java b/src/test/java/com/thealgorithms/others/HuffmanTest.java
new file mode 100644
index 000000000000..aa16f6493506
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/HuffmanTest.java
@@ -0,0 +1,223 @@
+package com.thealgorithms.others;
+
+import java.util.Map;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for Huffman coding algorithm.
+ * Tests various scenarios including normal cases, edge cases, and error
+ * conditions.
+ */
+class HuffmanTest {
+
+    @Test
+    void testBuildHuffmanTreeWithBasicInput() {
+        char[] charArray = {'a', 'b', 'c', 'd', 'e', 'f'};
+        int[] charFreq = {5, 9, 12, 13, 16, 45};
+
+        HuffmanNode root = Huffman.buildHuffmanTree(charArray, charFreq);
+
+        Assertions.assertNotNull(root);
+        Assertions.assertEquals(100, root.data); // Total frequency
+    }
+
+    @Test
+    void testGenerateCodesWithBasicInput() {
+        char[] charArray = {'a', 'b', 'c', 'd', 'e', 'f'};
+        int[] charFreq = {5, 9, 12, 13, 16, 45};
+
+        HuffmanNode root = Huffman.buildHuffmanTree(charArray, charFreq);
+        Map<Character, String> codes = Huffman.generateCodes(root);
+
+        Assertions.assertNotNull(codes);
+        Assertions.assertEquals(6, codes.size());
+
+        // Verify that all characters have codes
+        for (char c : charArray) {
+            Assertions.assertTrue(codes.containsKey(c), "Missing code for character: " + c);
+            Assertions.assertNotNull(codes.get(c), "Null code for character: " + c);
+        }
+
+        // Verify that higher frequency characters have shorter codes
+        // 'f' has the highest frequency (45), so it should have one of the shortest
+        // codes
+        Assertions.assertTrue(codes.get('f').length() <= codes.get('a').length());
+    }
+
+    @Test
+    void testSingleCharacter() {
+        char[] charArray = {'a'};
+        int[] charFreq = {10};
+
+        HuffmanNode root = Huffman.buildHuffmanTree(charArray, charFreq);
+        Map<Character, String> codes = Huffman.generateCodes(root);
+
+        Assertions.assertNotNull(codes);
+        Assertions.assertEquals(1, codes.size());
+        Assertions.assertEquals("0", codes.get('a')); // Single character gets code "0"
+    }
+
+    @Test
+    void testTwoCharacters() {
+        char[] charArray = {'a', 'b'};
+        int[] charFreq = {3, 7};
+
+        HuffmanNode root = Huffman.buildHuffmanTree(charArray, charFreq);
+        Map<Character, String> codes = Huffman.generateCodes(root);
+
+        Assertions.assertNotNull(codes);
+        Assertions.assertEquals(2, codes.size());
+
+        // Verify both characters have codes
+        Assertions.assertTrue(codes.containsKey('a'));
+        Assertions.assertTrue(codes.containsKey('b'));
+
+        // Verify codes are different
+        Assertions.assertNotEquals(codes.get('a'), codes.get('b'));
+    }
+
+    @Test
+    void testEqualFrequencies() {
+        char[] charArray = {'a', 'b', 'c'};
+        int[] charFreq = {5, 5, 5};
+
+        HuffmanNode root = Huffman.buildHuffmanTree(charArray, charFreq);
+        Map<Character, String> codes = Huffman.generateCodes(root);
+
+        Assertions.assertNotNull(codes);
+        Assertions.assertEquals(3, codes.size());
+
+        // Verify all characters have codes
+        for (char c : charArray) {
+            Assertions.assertTrue(codes.containsKey(c));
+        }
+    }
+
+    @Test
+    void testLargeFrequencyDifference() {
+        char[] charArray = {'a', 'b', 'c'};
+        int[] charFreq = {1, 10, 100};
+
+        HuffmanNode root = Huffman.buildHuffmanTree(charArray, charFreq);
+        Map<Character, String> codes = Huffman.generateCodes(root);
+
+        Assertions.assertNotNull(codes);
+        Assertions.assertEquals(3, codes.size());
+
+        // Character 'c' with highest frequency should have shortest code
+        Assertions.assertTrue(codes.get('c').length() <= codes.get('b').length());
+        Assertions.assertTrue(codes.get('c').length() <= codes.get('a').length());
+    }
+
+    @Test
+    void testNullCharacterArray() {
+        int[] charFreq = {5, 9, 12};
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { Huffman.buildHuffmanTree(null, charFreq); });
+    }
+
+    @Test
+    void testNullFrequencyArray() {
+        char[] charArray = {'a', 'b', 'c'};
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { Huffman.buildHuffmanTree(charArray, null); });
+    }
+
+    @Test
+    void testEmptyArrays() {
+        char[] charArray = {};
+        int[] charFreq = {};
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { Huffman.buildHuffmanTree(charArray, charFreq); });
+    }
+
+    @Test
+    void testMismatchedArrayLengths() {
+        char[] charArray = {'a', 'b', 'c'};
+        int[] charFreq = {5, 9};
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { Huffman.buildHuffmanTree(charArray, charFreq); });
+    }
+
+    @Test
+    void testNegativeFrequency() {
+        char[] charArray = {'a', 'b', 'c'};
+        int[] charFreq = {5, -9, 12};
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { Huffman.buildHuffmanTree(charArray, charFreq); });
+    }
+
+    @Test
+    void testZeroFrequency() {
+        char[] charArray = {'a', 'b', 'c'};
+        int[] charFreq = {0, 5, 10};
+
+        HuffmanNode root = Huffman.buildHuffmanTree(charArray, charFreq);
+        Map<Character, String> codes = Huffman.generateCodes(root);
+
+        Assertions.assertNotNull(codes);
+        Assertions.assertEquals(3, codes.size());
+        Assertions.assertTrue(codes.containsKey('a')); // Even with 0 frequency, character should have a code
+    }
+
+    @Test
+    void testGenerateCodesWithNullRoot() {
+        Map<Character, String> codes = Huffman.generateCodes(null);
+
+        Assertions.assertNotNull(codes);
+        Assertions.assertTrue(codes.isEmpty());
+    }
+
+    @Test
+    void testPrefixProperty() {
+        // Verify that no code is a prefix of another (Huffman property)
+        char[] charArray = {'a', 'b', 'c', 'd', 'e'};
+        int[] charFreq = {5, 9, 12, 13, 16};
+
+        HuffmanNode root = Huffman.buildHuffmanTree(charArray, charFreq);
+        Map<Character, String> codes = Huffman.generateCodes(root);
+
+        // Check that no code is a prefix of another
+        for (Map.Entry<Character, String> entry1 : codes.entrySet()) {
+            for (Map.Entry<Character, String> entry2 : codes.entrySet()) {
+                if (!entry1.getKey().equals(entry2.getKey())) {
+                    String code1 = entry1.getValue();
+                    String code2 = entry2.getValue();
+                    Assertions.assertTrue(!code1.startsWith(code2) && !code2.startsWith(code1), "Code " + code1 + " is a prefix of " + code2);
+                }
+            }
+        }
+    }
+
+    @Test
+    void testBinaryCodesOnly() {
+        // Verify that all codes contain only '0' and '1'
+        char[] charArray = {'a', 'b', 'c', 'd'};
+        int[] charFreq = {1, 2, 3, 4};
+
+        HuffmanNode root = Huffman.buildHuffmanTree(charArray, charFreq);
+        Map<Character, String> codes = Huffman.generateCodes(root);
+
+        for (String code : codes.values()) {
+            Assertions.assertTrue(code.matches("[01]+"), "Code contains non-binary characters: " + code);
+        }
+    }
+
+    @Test
+    void testMultipleCharactersWithLargeAlphabet() {
+        char[] charArray = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'};
+        int[] charFreq = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29};
+
+        HuffmanNode root = Huffman.buildHuffmanTree(charArray, charFreq);
+        Map<Character, String> codes = Huffman.generateCodes(root);
+
+        Assertions.assertNotNull(codes);
+        Assertions.assertEquals(10, codes.size());
+
+        // Verify all characters have codes
+        for (char c : charArray) {
+            Assertions.assertTrue(codes.containsKey(c));
+        }
+    }
+}

From 7fb4c8d60f1346a4b9c9e0c25accdda9ff7baa52 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 12 Oct 2025 11:37:17 +0530
Subject: [PATCH 1004/1338] refactor: Enhance docs, code, add tests in
 `MinimaxAlgorithm` (#6641)

* refactor: Enhance docs, code, add tests in `MinimaxAlgorithm`

* Fix

* Fix

* refactor: Enhance docs, code, add tests in `HappyNumbersSeq`

* Revert "refactor: Enhance docs, code, add tests in `HappyNumbersSeq`"

This reverts commit 9e8afb4f2c32b4d1c4acadaa0215c2eee23a040f.
---
 .../others/MiniMaxAlgorithm.java              | 140 ++++++++++---
 .../others/MiniMaxAlgorithmTest.java          | 195 ++++++++++++------
 2 files changed, 237 insertions(+), 98 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java b/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java
index e0b96570a4fe..28dc980034f3 100644
--- a/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java
@@ -4,54 +4,99 @@
 import java.util.Random;
 
 /**
- * MiniMax is an algorithm used int artificial intelligence and game theory for
- * minimizing the possible loss for the worst case scenario.
+ * MiniMax is an algorithm used in artificial intelligence and game theory for
+ * minimizing the possible loss for the worst case scenario. It is commonly used
+ * in two-player turn-based games such as Tic-Tac-Toe, Chess, and Checkers.
  *
- * See more (https://en.wikipedia.org/wiki/Minimax,
- * https://www.geeksforgeeks.org/minimax-algorithm-in-game-theory-set-1-introduction/).
+ * <p>
+ * The algorithm simulates all possible moves in a game tree and chooses the
+ * move that minimizes the maximum possible loss. The algorithm assumes both
+ * players play optimally.
+ *
+ * <p>
+ * Time Complexity: O(b^d) where b is the branching factor and d is the depth
+ * <p>
+ * Space Complexity: O(d) for the recursive call stack
+ *
+ * <p>
+ * See more:
+ * <ul>
+ * <li><a href="https://en.wikipedia.org/wiki/Minimax">Wikipedia - Minimax</a>
+ * <li><a href=
+ * "https://www.geeksforgeeks.org/minimax-algorithm-in-game-theory-set-1-introduction/">
+ * GeeksforGeeks - Minimax Algorithm</a>
+ * </ul>
  *
  * @author aitofi (https://github.com/aitorfi)
  */
-public class MiniMaxAlgorithm {
+public final class MiniMaxAlgorithm {
+
+    private static final Random RANDOM = new Random();
 
     /**
      * Game tree represented as an int array containing scores. Each array
-     * element is a leaf node.
+     * element is a leaf node. The array length must be a power of 2.
      */
     private int[] scores;
+
+    /**
+     * The height of the game tree, calculated as log2(scores.length).
+     */
     private int height;
 
     /**
-     * Initializes the scores with 8 random leaf nodes
+     * Initializes the MiniMaxAlgorithm with 8 random leaf nodes (2^3 = 8).
+     * Each score is a random integer between 1 and 99 inclusive.
      */
     public MiniMaxAlgorithm() {
-        scores = getRandomScores(3, 99);
-        height = log2(scores.length);
+        this(getRandomScores(3, 99));
+    }
+
+    /**
+     * Initializes the MiniMaxAlgorithm with the provided scores.
+     *
+     * @param scores An array of scores representing leaf nodes. The length must be
+     *               a power of 2.
+     * @throws IllegalArgumentException if the scores array length is not a power of
+     *                                  2
+     */
+    public MiniMaxAlgorithm(int[] scores) {
+        if (!isPowerOfTwo(scores.length)) {
+            throw new IllegalArgumentException("The number of scores must be a power of 2.");
+        }
+        this.scores = Arrays.copyOf(scores, scores.length);
+        this.height = log2(scores.length);
     }
 
+    /**
+     * Demonstrates the MiniMax algorithm with a random game tree.
+     *
+     * @param args Command line arguments (not used)
+     */
     public static void main(String[] args) {
-        MiniMaxAlgorithm miniMaxAlgorith = new MiniMaxAlgorithm();
+        MiniMaxAlgorithm miniMaxAlgorithm = new MiniMaxAlgorithm();
         boolean isMaximizer = true; // Specifies the player that goes first.
-        boolean verbose = true; // True to show each players choices.
         int bestScore;
 
-        bestScore = miniMaxAlgorith.miniMax(0, isMaximizer, 0, verbose);
+        bestScore = miniMaxAlgorithm.miniMax(0, isMaximizer, 0, true);
 
-        if (verbose) {
-            System.out.println();
-        }
-
-        System.out.println(Arrays.toString(miniMaxAlgorith.getScores()));
+        System.out.println();
+        System.out.println(Arrays.toString(miniMaxAlgorithm.getScores()));
         System.out.println("The best score for " + (isMaximizer ? "Maximizer" : "Minimizer") + " is " + bestScore);
     }
 
     /**
      * Returns the optimal score assuming that both players play their best.
      *
-     * @param depth Indicates how deep we are into the game tree.
-     * @param isMaximizer True if it is maximizers turn; otherwise false.
-     * @param index Index of the leaf node that is being evaluated.
-     * @param verbose True to show each players choices.
+     * <p>
+     * This method recursively evaluates the game tree using the minimax algorithm.
+     * At each level, the maximizer tries to maximize the score while the minimizer
+     * tries to minimize it.
+     *
+     * @param depth       The current depth in the game tree (0 at root).
+     * @param isMaximizer True if it is the maximizer's turn; false for minimizer.
+     * @param index       Index of the current node in the game tree.
+     * @param verbose     True to print each player's choice during evaluation.
      * @return The optimal score for the player that made the first move.
      */
     public int miniMax(int depth, boolean isMaximizer, int index, boolean verbose) {
@@ -75,7 +120,7 @@ public int miniMax(int depth, boolean isMaximizer, int index, boolean verbose) {
         }
 
         // Leaf nodes can be sequentially inspected by
-        // recurssively multiplying (0 * 2) and ((0 * 2) + 1):
+        // recursively multiplying (0 * 2) and ((0 * 2) + 1):
         // (0 x 2) = 0; ((0 x 2) + 1) = 1
         // (1 x 2) = 2; ((1 x 2) + 1) = 3
         // (2 x 2) = 4; ((2 x 2) + 1) = 5 ...
@@ -87,46 +132,73 @@ public int miniMax(int depth, boolean isMaximizer, int index, boolean verbose) {
     }
 
     /**
-     * Returns an array of random numbers which lenght is a power of 2.
+     * Returns an array of random numbers whose length is a power of 2.
      *
-     * @param size The power of 2 that will determine the lenght of the array.
-     * @param maxScore The maximum possible score.
-     * @return An array of random numbers.
+     * @param size     The power of 2 that will determine the length of the array
+     *                 (array length = 2^size).
+     * @param maxScore The maximum possible score (scores will be between 1 and
+     *                 maxScore inclusive).
+     * @return An array of random numbers with length 2^size.
      */
     public static int[] getRandomScores(int size, int maxScore) {
         int[] randomScores = new int[(int) Math.pow(2, size)];
-        Random rand = new Random();
 
         for (int i = 0; i < randomScores.length; i++) {
-            randomScores[i] = rand.nextInt(maxScore) + 1;
+            randomScores[i] = RANDOM.nextInt(maxScore) + 1;
         }
 
         return randomScores;
     }
 
-    // A utility function to find Log n in base 2
+    /**
+     * Calculates the logarithm base 2 of a number.
+     *
+     * @param n The number to calculate log2 for (must be a power of 2).
+     * @return The log2 of n.
+     */
     private int log2(int n) {
         return (n == 1) ? 0 : log2(n / 2) + 1;
     }
 
-    // A utility function to check if a number is a power of 2
+    /**
+     * Checks if a number is a power of 2.
+     *
+     * @param n The number to check.
+     * @return True if n is a power of 2, false otherwise.
+     */
     private boolean isPowerOfTwo(int n) {
         return n > 0 && (n & (n - 1)) == 0;
     }
 
+    /**
+     * Sets the scores array for the game tree.
+     *
+     * @param scores The array of scores. Length must be a power of 2.
+     * @throws IllegalArgumentException if the scores array length is not a power of
+     *                                  2
+     */
     public void setScores(int[] scores) {
         if (!isPowerOfTwo(scores.length)) {
-            System.out.println("The number of scores must be a power of 2.");
-            return;
+            throw new IllegalArgumentException("The number of scores must be a power of 2.");
         }
-        this.scores = scores;
+        this.scores = Arrays.copyOf(scores, scores.length);
         height = log2(this.scores.length);
     }
 
+    /**
+     * Returns a copy of the scores array.
+     *
+     * @return A copy of the scores array.
+     */
     public int[] getScores() {
-        return scores;
+        return Arrays.copyOf(scores, scores.length);
     }
 
+    /**
+     * Returns the height of the game tree.
+     *
+     * @return The height of the game tree (log2 of the number of leaf nodes).
+     */
     public int getHeight() {
         return height;
     }
diff --git a/src/test/java/com/thealgorithms/others/MiniMaxAlgorithmTest.java b/src/test/java/com/thealgorithms/others/MiniMaxAlgorithmTest.java
index 821eb3f16029..4e81c8b7e34f 100644
--- a/src/test/java/com/thealgorithms/others/MiniMaxAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/others/MiniMaxAlgorithmTest.java
@@ -1,12 +1,9 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
 import java.io.ByteArrayOutputStream;
 import java.io.PrintStream;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
@@ -26,56 +23,82 @@ void setUp() {
         System.setOut(new PrintStream(outputStream));
     }
 
+    @AfterEach
+    void tearDown() {
+        System.setOut(originalOut);
+    }
+
     @Test
     void testConstructorCreatesValidScores() {
         // The default constructor should create scores array of length 8 (2^3)
-        assertEquals(8, miniMax.getScores().length);
-        assertEquals(3, miniMax.getHeight());
+        Assertions.assertEquals(8, miniMax.getScores().length);
+        Assertions.assertEquals(3, miniMax.getHeight());
 
         // All scores should be positive (between 1 and 99)
         for (int score : miniMax.getScores()) {
-            assertTrue(score >= 1 && score <= 99);
+            Assertions.assertTrue(score >= 1 && score <= 99);
         }
     }
 
+    @Test
+    void testConstructorWithValidScores() {
+        int[] validScores = {10, 20, 30, 40};
+        MiniMaxAlgorithm customMiniMax = new MiniMaxAlgorithm(validScores);
+
+        Assertions.assertArrayEquals(validScores, customMiniMax.getScores());
+        Assertions.assertEquals(2, customMiniMax.getHeight()); // log2(4) = 2
+    }
+
+    @Test
+    void testConstructorWithInvalidScoresThrowsException() {
+        int[] invalidScores = {10, 20, 30}; // Length 3 is not a power of 2
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new MiniMaxAlgorithm(invalidScores));
+    }
+
+    @Test
+    void testConstructorDoesNotModifyOriginalArray() {
+        int[] originalScores = {10, 20, 30, 40};
+        int[] copyOfOriginal = {10, 20, 30, 40};
+        MiniMaxAlgorithm customMiniMax = new MiniMaxAlgorithm(originalScores);
+
+        // Modify the original array
+        originalScores[0] = 999;
+
+        // Constructor should have made a copy, so internal state should be unchanged
+        Assertions.assertArrayEquals(copyOfOriginal, customMiniMax.getScores());
+    }
+
     @Test
     void testSetScoresWithValidPowerOfTwo() {
         int[] validScores = {10, 20, 30, 40};
         miniMax.setScores(validScores);
 
-        assertArrayEquals(validScores, miniMax.getScores());
-        assertEquals(2, miniMax.getHeight()); // log2(4) = 2
+        Assertions.assertArrayEquals(validScores, miniMax.getScores());
+        Assertions.assertEquals(2, miniMax.getHeight()); // log2(4) = 2
     }
 
     @Test
     void testSetScoresWithInvalidLength() {
         int[] invalidScores = {10, 20, 30}; // Length 3 is not a power of 2
-        miniMax.setScores(invalidScores);
-
-        // Should print error message and not change the scores
-        String output = outputStream.toString();
-        assertTrue(output.contains("The number of scores must be a power of 2."));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> miniMax.setScores(invalidScores));
 
         // Scores should remain unchanged (original length 8)
-        assertEquals(8, miniMax.getScores().length);
+        Assertions.assertEquals(8, miniMax.getScores().length);
     }
 
     @Test
     void testSetScoresWithZeroLength() {
         int[] emptyScores = {}; // Length 0 is not a power of 2
-        miniMax.setScores(emptyScores);
-
-        // Should print error message and not change the scores
-        String output = outputStream.toString();
-        assertTrue(output.contains("The number of scores must be a power of 2."));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> miniMax.setScores(emptyScores));
 
         // Scores should remain unchanged (original length 8)
-        assertEquals(8, miniMax.getScores().length);
+        Assertions.assertEquals(8, miniMax.getScores().length);
     }
 
     @Test
     void testSetScoresWithVariousInvalidLengths() {
-        // Test multiple invalid lengths to ensure isPowerOfTwo function is fully covered
+        // Test multiple invalid lengths to ensure isPowerOfTwo function is fully
+        // covered
         int[][] invalidScoreArrays = {
             {1, 2, 3, 4, 5}, // Length 5
             {1, 2, 3, 4, 5, 6}, // Length 6
@@ -86,17 +109,11 @@ void testSetScoresWithVariousInvalidLengths() {
         };
 
         for (int[] invalidScores : invalidScoreArrays) {
-            // Clear the output stream for each test
-            outputStream.reset();
-            miniMax.setScores(invalidScores);
-
-            // Should print error message for each invalid length
-            String output = outputStream.toString();
-            assertTrue(output.contains("The number of scores must be a power of 2."), "Failed for array length: " + invalidScores.length);
+            Assertions.assertThrows(IllegalArgumentException.class, () -> miniMax.setScores(invalidScores), "Failed for array length: " + invalidScores.length);
         }
 
         // Scores should remain unchanged (original length 8)
-        assertEquals(8, miniMax.getScores().length);
+        Assertions.assertEquals(8, miniMax.getScores().length);
     }
 
     @Test
@@ -104,8 +121,8 @@ void testSetScoresWithSingleElement() {
         int[] singleScore = {42};
         miniMax.setScores(singleScore);
 
-        assertArrayEquals(singleScore, miniMax.getScores());
-        assertEquals(0, miniMax.getHeight()); // log2(1) = 0
+        Assertions.assertArrayEquals(singleScore, miniMax.getScores());
+        Assertions.assertEquals(0, miniMax.getHeight()); // log2(1) = 0
     }
 
     @Test
@@ -116,7 +133,7 @@ void testMiniMaxWithKnownScores() {
 
         // Maximizer starts: should choose max(min(3,12), min(8,2)) = max(3, 2) = 3
         int result = miniMax.miniMax(0, true, 0, false);
-        assertEquals(3, result);
+        Assertions.assertEquals(3, result);
     }
 
     @Test
@@ -127,7 +144,7 @@ void testMiniMaxWithMinimizerFirst() {
 
         // Minimizer starts: should choose min(max(3,12), max(8,2)) = min(12, 8) = 8
         int result = miniMax.miniMax(0, false, 0, false);
-        assertEquals(8, result);
+        Assertions.assertEquals(8, result);
     }
 
     @Test
@@ -139,8 +156,8 @@ void testMiniMaxWithLargerTree() {
         // Maximizer starts
         int result = miniMax.miniMax(0, true, 0, false);
         // Expected: max(min(max(5,6), max(7,4)), min(max(5,3), max(6,2)))
-        //         = max(min(6, 7), min(5, 6)) = max(6, 5) = 6
-        assertEquals(6, result);
+        // = max(min(6, 7), min(5, 6)) = max(6, 5) = 6
+        Assertions.assertEquals(6, result);
     }
 
     @Test
@@ -151,41 +168,41 @@ void testMiniMaxVerboseOutput() {
         miniMax.miniMax(0, true, 0, true);
 
         String output = outputStream.toString();
-        assertTrue(output.contains("Maximizer"));
-        assertTrue(output.contains("Minimizer"));
-        assertTrue(output.contains("chooses"));
+        Assertions.assertTrue(output.contains("Maximizer"));
+        Assertions.assertTrue(output.contains("Minimizer"));
+        Assertions.assertTrue(output.contains("chooses"));
     }
 
     @Test
     void testGetRandomScoresLength() {
         int[] randomScores = MiniMaxAlgorithm.getRandomScores(4, 50);
-        assertEquals(16, randomScores.length); // 2^4 = 16
+        Assertions.assertEquals(16, randomScores.length); // 2^4 = 16
 
         // All scores should be between 1 and 50
         for (int score : randomScores) {
-            assertTrue(score >= 1 && score <= 50);
+            Assertions.assertTrue(score >= 1 && score <= 50);
         }
     }
 
     @Test
     void testGetRandomScoresWithDifferentParameters() {
         int[] randomScores = MiniMaxAlgorithm.getRandomScores(2, 10);
-        assertEquals(4, randomScores.length); // 2^2 = 4
+        Assertions.assertEquals(4, randomScores.length); // 2^2 = 4
 
         // All scores should be between 1 and 10
         for (int score : randomScores) {
-            assertTrue(score >= 1 && score <= 10);
+            Assertions.assertTrue(score >= 1 && score <= 10);
         }
     }
 
     @Test
     void testMainMethod() {
         // Test that main method runs without errors
-        assertDoesNotThrow(() -> MiniMaxAlgorithm.main(new String[] {}));
+        Assertions.assertDoesNotThrow(() -> MiniMaxAlgorithm.main(new String[] {}));
 
         String output = outputStream.toString();
-        assertTrue(output.contains("The best score for"));
-        assertTrue(output.contains("Maximizer"));
+        Assertions.assertTrue(output.contains("The best score for"));
+        Assertions.assertTrue(output.contains("Maximizer"));
     }
 
     @Test
@@ -193,11 +210,11 @@ void testHeightCalculation() {
         // Test height calculation for different array sizes
         int[] scores2 = {1, 2};
         miniMax.setScores(scores2);
-        assertEquals(1, miniMax.getHeight()); // log2(2) = 1
+        Assertions.assertEquals(1, miniMax.getHeight()); // log2(2) = 1
 
         int[] scores16 = new int[16];
         miniMax.setScores(scores16);
-        assertEquals(4, miniMax.getHeight()); // log2(16) = 4
+        Assertions.assertEquals(4, miniMax.getHeight()); // log2(16) = 4
     }
 
     @Test
@@ -206,7 +223,7 @@ void testEdgeCaseWithZeroScores() {
         miniMax.setScores(zeroScores);
 
         int result = miniMax.miniMax(0, true, 0, false);
-        assertEquals(0, result);
+        Assertions.assertEquals(0, result);
     }
 
     @Test
@@ -218,11 +235,7 @@ void testEdgeCaseWithNegativeScores() {
         // Level 1 (minimizer): min(-5,-2) = -5, min(-8,-1) = -8
         // Level 0 (maximizer): max(-5, -8) = -5
         int result = miniMax.miniMax(0, true, 0, false);
-        assertEquals(-5, result);
-    }
-
-    void tearDown() {
-        System.setOut(originalOut);
+        Assertions.assertEquals(-5, result);
     }
 
     @Test
@@ -233,12 +246,9 @@ void testSetScoresWithNegativeLength() {
 
         // Test with array length 0 (edge case for n > 0 condition)
         int[] emptyArray = new int[0];
-        outputStream.reset();
-        miniMax.setScores(emptyArray);
+        Assertions.assertThrows(IllegalArgumentException.class, () -> miniMax.setScores(emptyArray));
 
-        String output = outputStream.toString();
-        assertTrue(output.contains("The number of scores must be a power of 2."));
-        assertEquals(8, miniMax.getScores().length); // Should remain unchanged
+        Assertions.assertEquals(8, miniMax.getScores().length); // Should remain unchanged
     }
 
     @Test
@@ -250,8 +260,8 @@ void testSetScoresWithLargePowerOfTwo() {
         }
 
         miniMax.setScores(largeValidScores);
-        assertArrayEquals(largeValidScores, miniMax.getScores());
-        assertEquals(5, miniMax.getHeight()); // log2(32) = 5
+        Assertions.assertArrayEquals(largeValidScores, miniMax.getScores());
+        Assertions.assertEquals(5, miniMax.getHeight()); // log2(32) = 5
     }
 
     @Test
@@ -270,8 +280,65 @@ void testSetScoresValidEdgeCases() {
 
         for (int i = 0; i < validPowersOf2.length; i++) {
             miniMax.setScores(validPowersOf2[i]);
-            assertEquals(validPowersOf2[i].length, miniMax.getScores().length, "Failed for array length: " + validPowersOf2[i].length);
-            assertEquals(expectedHeights[i], miniMax.getHeight(), "Height calculation failed for array length: " + validPowersOf2[i].length);
+            Assertions.assertEquals(validPowersOf2[i].length, miniMax.getScores().length, "Failed for array length: " + validPowersOf2[i].length);
+            Assertions.assertEquals(expectedHeights[i], miniMax.getHeight(), "Height calculation failed for array length: " + validPowersOf2[i].length);
         }
     }
+
+    @Test
+    void testGetScoresReturnsDefensiveCopy() {
+        int[] originalScores = {10, 20, 30, 40};
+        miniMax.setScores(originalScores);
+
+        // Get the scores and modify them
+        int[] retrievedScores = miniMax.getScores();
+        retrievedScores[0] = 999;
+
+        // Internal state should remain unchanged
+        Assertions.assertEquals(10, miniMax.getScores()[0]);
+    }
+
+    @Test
+    void testSetScoresCreatesDefensiveCopy() {
+        int[] originalScores = {10, 20, 30, 40};
+        miniMax.setScores(originalScores);
+
+        // Modify the original array after setting
+        originalScores[0] = 999;
+
+        // Internal state should remain unchanged
+        Assertions.assertEquals(10, miniMax.getScores()[0]);
+    }
+
+    @Test
+    void testMiniMaxWithAllSameScores() {
+        int[] sameScores = {5, 5, 5, 5};
+        miniMax.setScores(sameScores);
+
+        // When all scores are the same, result should be that score
+        int result = miniMax.miniMax(0, true, 0, false);
+        Assertions.assertEquals(5, result);
+    }
+
+    @Test
+    void testMiniMaxAtDifferentDepths() {
+        int[] testScores = {3, 12, 8, 2, 14, 5, 2, 9};
+        miniMax.setScores(testScores);
+
+        // Test maximizer first
+        int result = miniMax.miniMax(0, true, 0, false);
+        // Expected: max(min(max(3,12), max(8,2)), min(max(14,5), max(2,9)))
+        // = max(min(12, 8), min(14, 9)) = max(8, 9) = 9
+        Assertions.assertEquals(9, result);
+    }
+
+    @Test
+    void testMiniMaxWithMinIntAndMaxInt() {
+        int[] extremeScores = {Integer.MIN_VALUE, Integer.MAX_VALUE, 0, 1};
+        miniMax.setScores(extremeScores);
+
+        int result = miniMax.miniMax(0, true, 0, false);
+        // Expected: max(min(MIN, MAX), min(0, 1)) = max(MIN, 0) = 0
+        Assertions.assertEquals(0, result);
+    }
 }

From c0ca70498bcfcb9e7f50603f54342eb62cb10a2b Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 12 Oct 2025 11:43:58 +0530
Subject: [PATCH 1005/1338] refactor: Enhance docs, code, add tests in
 `PageRank` (#6642)

---
 .../com/thealgorithms/others/PageRank.java    | 346 ++++++++++++++----
 .../thealgorithms/others/PageRankTest.java    | 319 ++++++++++++++++
 2 files changed, 598 insertions(+), 67 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/others/PageRankTest.java

diff --git a/src/main/java/com/thealgorithms/others/PageRank.java b/src/main/java/com/thealgorithms/others/PageRank.java
index c7be7a9882bc..2899b80bcee8 100644
--- a/src/main/java/com/thealgorithms/others/PageRank.java
+++ b/src/main/java/com/thealgorithms/others/PageRank.java
@@ -2,94 +2,306 @@
 
 import java.util.Scanner;
 
-class PageRank {
+/**
+ * PageRank Algorithm Implementation
+ *
+ * <p>
+ * The PageRank algorithm is used by Google Search to rank web pages in their
+ * search engine
+ * results. It was named after Larry Page, one of the founders of Google.
+ * PageRank is a way of
+ * measuring the importance of website pages.
+ *
+ * <p>
+ * Algorithm: 1. Initialize PageRank values for all pages to 1/N (where N is the
+ * total number
+ * of pages) 2. For each iteration: - For each page, calculate the new PageRank
+ * by summing the
+ * contributions from all incoming links - Apply the damping factor: PR(page) =
+ * (1-d) + d *
+ * sum(PR(incoming_page) / outgoing_links(incoming_page)) 3. Repeat until
+ * convergence
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/PageRank">PageRank Algorithm</a>
+ */
+public final class PageRank {
 
+    private static final int MAX_NODES = 10;
+    private static final double DEFAULT_DAMPING_FACTOR = 0.85;
+    private static final int DEFAULT_ITERATIONS = 2;
+
+    private int[][] adjacencyMatrix;
+    private double[] pageRankValues;
+    private int nodeCount;
+
+    /**
+     * Constructor to initialize PageRank with specified number of nodes
+     *
+     * @param numberOfNodes the number of nodes/pages in the graph
+     * @throws IllegalArgumentException if numberOfNodes is less than 1 or greater
+     *                                  than MAX_NODES
+     */
+    public PageRank(int numberOfNodes) {
+        if (numberOfNodes < 1 || numberOfNodes > MAX_NODES) {
+            throw new IllegalArgumentException("Number of nodes must be between 1 and " + MAX_NODES);
+        }
+        this.nodeCount = numberOfNodes;
+        this.adjacencyMatrix = new int[MAX_NODES][MAX_NODES];
+        this.pageRankValues = new double[MAX_NODES];
+    }
+
+    /**
+     * Default constructor for interactive mode
+     */
+    public PageRank() {
+        this.adjacencyMatrix = new int[MAX_NODES][MAX_NODES];
+        this.pageRankValues = new double[MAX_NODES];
+    }
+
+    /**
+     * Main method for interactive PageRank calculation
+     *
+     * @param args command line arguments (not used)
+     */
     public static void main(String[] args) {
-        int nodes;
-        int i;
-        int j;
-        Scanner in = new Scanner(System.in);
-        System.out.print("Enter the Number of WebPages: ");
-        nodes = in.nextInt();
-        PageRank p = new PageRank();
-        System.out.println("Enter the Adjacency Matrix with 1->PATH & 0->NO PATH Between two WebPages: ");
-        for (i = 1; i <= nodes; i++) {
-            for (j = 1; j <= nodes; j++) {
-                p.path[i][j] = in.nextInt();
-                if (j == i) {
-                    p.path[i][j] = 0;
+        try (Scanner scanner = new Scanner(System.in)) {
+            System.out.print("Enter the Number of WebPages: ");
+            int nodes = scanner.nextInt();
+
+            PageRank pageRank = new PageRank(nodes);
+            System.out.println("Enter the Adjacency Matrix with 1->PATH & 0->NO PATH Between two WebPages: ");
+
+            for (int i = 1; i <= nodes; i++) {
+                for (int j = 1; j <= nodes; j++) {
+                    int value = scanner.nextInt();
+                    pageRank.setEdge(i, j, value);
                 }
             }
+
+            pageRank.calculatePageRank(nodes, DEFAULT_DAMPING_FACTOR, DEFAULT_ITERATIONS, true);
         }
-        p.calc(nodes);
     }
 
-    public int[][] path = new int[10][10];
-    public double[] pagerank = new double[10];
+    /**
+     * Sets an edge in the adjacency matrix
+     *
+     * @param from  source node (1-indexed)
+     * @param to    destination node (1-indexed)
+     * @param value 1 if edge exists, 0 otherwise
+     */
+    public void setEdge(int from, int to, int value) {
+        if (from == to) {
+            adjacencyMatrix[from][to] = 0; // No self-loops
+        } else {
+            adjacencyMatrix[from][to] = value;
+        }
+    }
 
-    public void calc(double totalNodes) {
-        double initialPageRank;
-        double outgoingLinks = 0;
-        double dampingFactor = 0.85;
-        double[] tempPageRank = new double[10];
-        int externalNodeNumber;
-        int internalNodeNumber;
-        int k = 1; // For Traversing
-        int iterationStep = 1;
-        initialPageRank = 1 / totalNodes;
-        System.out.printf(" Total Number of Nodes :" + totalNodes + "\t Initial PageRank  of All Nodes :" + initialPageRank + "\n");
+    /**
+     * Sets the adjacency matrix for the graph
+     *
+     * @param matrix the adjacency matrix (1-indexed)
+     */
+    public void setAdjacencyMatrix(int[][] matrix) {
+        for (int i = 1; i <= nodeCount; i++) {
+            for (int j = 1; j <= nodeCount; j++) {
+                setEdge(i, j, matrix[i][j]);
+            }
+        }
+    }
 
-        // 0th ITERATION _ OR _ INITIALIZATION PHASE //
-        for (k = 1; k <= totalNodes; k++) {
-            this.pagerank[k] = initialPageRank;
+    /**
+     * Gets the PageRank value for a specific node
+     *
+     * @param node the node index (1-indexed)
+     * @return the PageRank value
+     */
+    public double getPageRank(int node) {
+        if (node < 1 || node > nodeCount) {
+            throw new IllegalArgumentException("Node index out of bounds");
         }
-        System.out.print("\n Initial PageRank Values , 0th Step \n");
+        return pageRankValues[node];
+    }
+
+    /**
+     * Gets all PageRank values
+     *
+     * @return array of PageRank values (1-indexed)
+     */
+    public double[] getAllPageRanks() {
+        return pageRankValues.clone();
+    }
+
+    /**
+     * Calculates PageRank using the default damping factor and iterations
+     *
+     * @param totalNodes the total number of nodes
+     * @return array of PageRank values
+     */
+    public double[] calculatePageRank(int totalNodes) {
+        return calculatePageRank(totalNodes, DEFAULT_DAMPING_FACTOR, DEFAULT_ITERATIONS, false);
+    }
+
+    /**
+     * Calculates PageRank with custom parameters
+     *
+     * @param totalNodes    the total number of nodes
+     * @param dampingFactor the damping factor (typically 0.85)
+     * @param iterations    number of iterations to perform
+     * @param verbose       whether to print detailed output
+     * @return array of PageRank values
+     */
+    public double[] calculatePageRank(int totalNodes, double dampingFactor, int iterations, boolean verbose) {
+        validateInputParameters(totalNodes, dampingFactor, iterations);
 
-        for (k = 1; k <= totalNodes; k++) {
-            System.out.printf(" Page Rank of " + k + " is :\t" + this.pagerank[k] + "\n");
+        this.nodeCount = totalNodes;
+        double initialPageRank = 1.0 / totalNodes;
+
+        if (verbose) {
+            System.out.printf("Total Number of Nodes: %d\tInitial PageRank of All Nodes: %.6f%n", totalNodes, initialPageRank);
         }
 
-        while (iterationStep <= 2) { // Iterations
-            // Store the PageRank for All Nodes in Temporary Array
-            for (k = 1; k <= totalNodes; k++) {
-                tempPageRank[k] = this.pagerank[k];
-                this.pagerank[k] = 0;
-            }
+        initializePageRanks(totalNodes, initialPageRank, verbose);
+        performIterations(totalNodes, dampingFactor, iterations, verbose);
 
-            for (internalNodeNumber = 1; internalNodeNumber <= totalNodes; internalNodeNumber++) {
-                for (externalNodeNumber = 1; externalNodeNumber <= totalNodes; externalNodeNumber++) {
-                    if (this.path[externalNodeNumber][internalNodeNumber] == 1) {
-                        k = 1;
-                        outgoingLinks = 0; // Count the Number of Outgoing Links for each externalNodeNumber
-                        while (k <= totalNodes) {
-                            if (this.path[externalNodeNumber][k] == 1) {
-                                outgoingLinks = outgoingLinks + 1; // Counter for Outgoing Links
-                            }
-                            k = k + 1;
-                        }
-                        // Calculate PageRank
-                        this.pagerank[internalNodeNumber] += tempPageRank[externalNodeNumber] * (1 / outgoingLinks);
-                    }
-                }
-                System.out.printf("\n After " + iterationStep + "th Step \n");
+        if (verbose) {
+            System.out.println("\nFinal PageRank:");
+            printPageRanks(totalNodes);
+        }
 
-                for (k = 1; k <= totalNodes; k++) {
-                    System.out.printf(" Page Rank of " + k + " is :\t" + this.pagerank[k] + "\n");
-                }
+        return pageRankValues.clone();
+    }
+
+    /**
+     * Validates input parameters for PageRank calculation
+     *
+     * @param totalNodes    the total number of nodes
+     * @param dampingFactor the damping factor
+     * @param iterations    number of iterations
+     * @throws IllegalArgumentException if parameters are invalid
+     */
+    private void validateInputParameters(int totalNodes, double dampingFactor, int iterations) {
+        if (totalNodes < 1 || totalNodes > MAX_NODES) {
+            throw new IllegalArgumentException("Total nodes must be between 1 and " + MAX_NODES);
+        }
+        if (dampingFactor < 0 || dampingFactor > 1) {
+            throw new IllegalArgumentException("Damping factor must be between 0 and 1");
+        }
+        if (iterations < 1) {
+            throw new IllegalArgumentException("Iterations must be at least 1");
+        }
+    }
+
+    /**
+     * Initializes PageRank values for all nodes
+     *
+     * @param totalNodes      the total number of nodes
+     * @param initialPageRank the initial PageRank value
+     * @param verbose         whether to print output
+     */
+    private void initializePageRanks(int totalNodes, double initialPageRank, boolean verbose) {
+        for (int i = 1; i <= totalNodes; i++) {
+            pageRankValues[i] = initialPageRank;
+        }
+
+        if (verbose) {
+            System.out.println("\nInitial PageRank Values, 0th Step");
+            printPageRanks(totalNodes);
+        }
+    }
 
-                iterationStep = iterationStep + 1;
+    /**
+     * Performs the iterative PageRank calculation
+     *
+     * @param totalNodes    the total number of nodes
+     * @param dampingFactor the damping factor
+     * @param iterations    number of iterations
+     * @param verbose       whether to print output
+     */
+    private void performIterations(int totalNodes, double dampingFactor, int iterations, boolean verbose) {
+        for (int iteration = 1; iteration <= iterations; iteration++) {
+            double[] tempPageRank = storeCurrentPageRanks(totalNodes);
+            calculateNewPageRanks(totalNodes, tempPageRank);
+            applyDampingFactor(totalNodes, dampingFactor);
+
+            if (verbose) {
+                System.out.printf("%nAfter %d iteration(s)%n", iteration);
+                printPageRanks(totalNodes);
             }
+        }
+    }
 
-            // Add the Damping Factor to PageRank
-            for (k = 1; k <= totalNodes; k++) {
-                this.pagerank[k] = (1 - dampingFactor) + dampingFactor * this.pagerank[k];
+    /**
+     * Stores current PageRank values in a temporary array
+     *
+     * @param totalNodes the total number of nodes
+     * @return temporary array with current PageRank values
+     */
+    private double[] storeCurrentPageRanks(int totalNodes) {
+        double[] tempPageRank = new double[MAX_NODES];
+        for (int i = 1; i <= totalNodes; i++) {
+            tempPageRank[i] = pageRankValues[i];
+            pageRankValues[i] = 0;
+        }
+        return tempPageRank;
+    }
+
+    /**
+     * Calculates new PageRank values based on incoming links
+     *
+     * @param totalNodes   the total number of nodes
+     * @param tempPageRank temporary array with previous PageRank values
+     */
+    private void calculateNewPageRanks(int totalNodes, double[] tempPageRank) {
+        for (int targetNode = 1; targetNode <= totalNodes; targetNode++) {
+            for (int sourceNode = 1; sourceNode <= totalNodes; sourceNode++) {
+                if (adjacencyMatrix[sourceNode][targetNode] == 1) {
+                    int outgoingLinks = countOutgoingLinks(sourceNode, totalNodes);
+                    if (outgoingLinks > 0) {
+                        pageRankValues[targetNode] += tempPageRank[sourceNode] / outgoingLinks;
+                    }
+                }
             }
+        }
+    }
 
-            // Display PageRank
-            System.out.print("\n Final Page Rank : \n");
-            for (k = 1; k <= totalNodes; k++) {
-                System.out.printf(" Page Rank of " + k + " is :\t" + this.pagerank[k] + "\n");
+    /**
+     * Applies the damping factor to all PageRank values
+     *
+     * @param totalNodes    the total number of nodes
+     * @param dampingFactor the damping factor
+     */
+    private void applyDampingFactor(int totalNodes, double dampingFactor) {
+        for (int i = 1; i <= totalNodes; i++) {
+            pageRankValues[i] = (1 - dampingFactor) + dampingFactor * pageRankValues[i];
+        }
+    }
+
+    /**
+     * Counts the number of outgoing links from a node
+     *
+     * @param node       the source node (1-indexed)
+     * @param totalNodes total number of nodes
+     * @return the count of outgoing links
+     */
+    private int countOutgoingLinks(int node, int totalNodes) {
+        int count = 0;
+        for (int i = 1; i <= totalNodes; i++) {
+            if (adjacencyMatrix[node][i] == 1) {
+                count++;
             }
         }
+        return count;
+    }
+
+    /**
+     * Prints the PageRank values for all nodes
+     *
+     * @param totalNodes the total number of nodes
+     */
+    private void printPageRanks(int totalNodes) {
+        for (int i = 1; i <= totalNodes; i++) {
+            System.out.printf("PageRank of %d: %.6f%n", i, pageRankValues[i]);
+        }
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/PageRankTest.java b/src/test/java/com/thealgorithms/others/PageRankTest.java
new file mode 100644
index 000000000000..de96403dd1fc
--- /dev/null
+++ b/src/test/java/com/thealgorithms/others/PageRankTest.java
@@ -0,0 +1,319 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for PageRank algorithm implementation
+ *
+ * @author Hardvan
+ */
+class PageRankTest {
+
+    private static final double EPSILON = 0.0001; // Tolerance for floating point comparisons
+
+    /**
+     * Test basic PageRank calculation with a simple 3-node graph
+     * Graph: 1 -> 2, 2 -> 3, 3 -> 1
+     */
+    @Test
+    void testSimpleThreeNodeGraph() {
+        PageRank pageRank = new PageRank(3);
+
+        // Create a simple circular graph: 1 -> 2 -> 3 -> 1
+        int[][] adjacencyMatrix = new int[10][10];
+        adjacencyMatrix[1][2] = 1; // Node 1 links to Node 2
+        adjacencyMatrix[2][3] = 1; // Node 2 links to Node 3
+        adjacencyMatrix[3][1] = 1; // Node 3 links to Node 1
+
+        pageRank.setAdjacencyMatrix(adjacencyMatrix);
+        double[] result = pageRank.calculatePageRank(3);
+
+        // All nodes should have equal PageRank in a circular graph
+        assertNotNull(result);
+        assertEquals(result[1], result[2], EPSILON);
+        assertEquals(result[2], result[3], EPSILON);
+    }
+
+    /**
+     * Test PageRank with a two-node graph where one node points to another
+     */
+    @Test
+    void testTwoNodeGraph() {
+        PageRank pageRank = new PageRank(2);
+
+        // Node 1 links to Node 2
+        pageRank.setEdge(1, 2, 1);
+
+        double[] result = pageRank.calculatePageRank(2);
+
+        // Node 2 should have higher PageRank than Node 1 (after 2 iterations)
+        assertNotNull(result);
+        assertEquals(0.2775, result[2], EPSILON);
+        assertEquals(0.15, result[1], EPSILON);
+    }
+
+    /**
+     * Test PageRank with a single node (no links)
+     */
+    @Test
+    void testSingleNode() {
+        PageRank pageRank = new PageRank(1);
+
+        double[] result = pageRank.calculatePageRank(1);
+
+        // Single node should have (1-d) = 0.15 after applying damping
+        assertNotNull(result);
+        assertEquals(0.15, result[1], EPSILON);
+    }
+
+    /**
+     * Test PageRank with a hub-and-spoke configuration
+     * Node 1 is the hub, pointing to nodes 2, 3, and 4
+     */
+    @Test
+    void testHubAndSpokeGraph() {
+        PageRank pageRank = new PageRank(4);
+
+        // Hub node (1) links to all other nodes
+        pageRank.setEdge(1, 2, 1);
+        pageRank.setEdge(1, 3, 1);
+        pageRank.setEdge(1, 4, 1);
+
+        // All spokes link back to hub
+        pageRank.setEdge(2, 1, 1);
+        pageRank.setEdge(3, 1, 1);
+        pageRank.setEdge(4, 1, 1);
+
+        double[] result = pageRank.calculatePageRank(4);
+
+        assertNotNull(result);
+        // Hub should have higher PageRank
+        assertEquals(result[2], result[3], EPSILON);
+        assertEquals(result[3], result[4], EPSILON);
+    }
+
+    /**
+     * Test PageRank with multiple iterations
+     */
+    @Test
+    void testMultipleIterations() {
+        PageRank pageRank = new PageRank(3);
+
+        pageRank.setEdge(1, 2, 1);
+        pageRank.setEdge(2, 3, 1);
+        pageRank.setEdge(3, 1, 1);
+
+        double[] result2Iterations = pageRank.calculatePageRank(3, 0.85, 2, false);
+        double[] result5Iterations = pageRank.calculatePageRank(3, 0.85, 5, false);
+
+        assertNotNull(result2Iterations);
+        assertNotNull(result5Iterations);
+    }
+
+    /**
+     * Test getPageRank method for individual node
+     */
+    @Test
+    void testGetPageRank() {
+        PageRank pageRank = new PageRank(2);
+
+        pageRank.setEdge(1, 2, 1);
+        pageRank.calculatePageRank(2);
+
+        double node1PageRank = pageRank.getPageRank(1);
+        double node2PageRank = pageRank.getPageRank(2);
+
+        assertEquals(0.15, node1PageRank, EPSILON);
+        assertEquals(0.2775, node2PageRank, EPSILON);
+    }
+
+    /**
+     * Test getAllPageRanks method
+     */
+    @Test
+    void testGetAllPageRanks() {
+        PageRank pageRank = new PageRank(2);
+
+        pageRank.setEdge(1, 2, 1);
+        pageRank.calculatePageRank(2);
+
+        double[] allPageRanks = pageRank.getAllPageRanks();
+
+        assertNotNull(allPageRanks);
+        assertEquals(0.15, allPageRanks[1], EPSILON);
+        assertEquals(0.2775, allPageRanks[2], EPSILON);
+    }
+
+    /**
+     * Test that self-loops are not allowed
+     */
+    @Test
+    void testNoSelfLoops() {
+        PageRank pageRank = new PageRank(2);
+
+        // Try to set a self-loop
+        pageRank.setEdge(1, 1, 1);
+        pageRank.setEdge(1, 2, 1);
+
+        double[] result = pageRank.calculatePageRank(2);
+
+        assertNotNull(result);
+        // Self-loop should be ignored
+    }
+
+    /**
+     * Test exception when node count is too small
+     */
+    @Test
+    void testInvalidNodeCountTooSmall() {
+        assertThrows(IllegalArgumentException.class, () -> new PageRank(0));
+    }
+
+    /**
+     * Test exception when node count is too large
+     */
+    @Test
+    void testInvalidNodeCountTooLarge() {
+        assertThrows(IllegalArgumentException.class, () -> new PageRank(11));
+    }
+
+    /**
+     * Test exception for invalid damping factor (negative)
+     */
+    @Test
+    void testInvalidDampingFactorNegative() {
+        PageRank pageRank = new PageRank(2);
+        pageRank.setEdge(1, 2, 1);
+
+        assertThrows(IllegalArgumentException.class, () -> pageRank.calculatePageRank(2, -0.1, 2, false));
+    }
+
+    /**
+     * Test exception for invalid damping factor (greater than 1)
+     */
+    @Test
+    void testInvalidDampingFactorTooLarge() {
+        PageRank pageRank = new PageRank(2);
+        pageRank.setEdge(1, 2, 1);
+
+        assertThrows(IllegalArgumentException.class, () -> pageRank.calculatePageRank(2, 1.5, 2, false));
+    }
+
+    /**
+     * Test exception for invalid iterations (less than 1)
+     */
+    @Test
+    void testInvalidIterations() {
+        PageRank pageRank = new PageRank(2);
+        pageRank.setEdge(1, 2, 1);
+
+        assertThrows(IllegalArgumentException.class, () -> pageRank.calculatePageRank(2, 0.85, 0, false));
+    }
+
+    /**
+     * Test exception when getting PageRank for invalid node
+     */
+    @Test
+    void testGetPageRankInvalidNode() {
+        PageRank pageRank = new PageRank(2);
+        pageRank.calculatePageRank(2);
+
+        assertThrows(IllegalArgumentException.class, () -> pageRank.getPageRank(3));
+    }
+
+    /**
+     * Test exception when getting PageRank for node less than 1
+     */
+    @Test
+    void testGetPageRankNodeLessThanOne() {
+        PageRank pageRank = new PageRank(2);
+        pageRank.calculatePageRank(2);
+
+        assertThrows(IllegalArgumentException.class, () -> pageRank.getPageRank(0));
+    }
+
+    /**
+     * Test complex graph with multiple incoming and outgoing links
+     */
+    @Test
+    void testComplexGraph() {
+        PageRank pageRank = new PageRank(4);
+
+        // Create a more complex graph
+        pageRank.setEdge(1, 2, 1);
+        pageRank.setEdge(1, 3, 1);
+        pageRank.setEdge(2, 3, 1);
+        pageRank.setEdge(3, 4, 1);
+        pageRank.setEdge(4, 1, 1);
+
+        double[] result = pageRank.calculatePageRank(4);
+
+        assertNotNull(result);
+        // Node 3 should have high PageRank (receives links from nodes 1 and 2)
+        // After 2 iterations, the sum will not equal total nodes
+        double sum = result[1] + result[2] + result[3] + result[4];
+        assertEquals(1.8325, sum, EPSILON);
+    }
+
+    /**
+     * Test that PageRank values sum after 2 iterations
+     */
+    @Test
+    void testPageRankSum() {
+        PageRank pageRank = new PageRank(5);
+
+        // Create arbitrary graph
+        pageRank.setEdge(1, 2, 1);
+        pageRank.setEdge(2, 3, 1);
+        pageRank.setEdge(3, 4, 1);
+        pageRank.setEdge(4, 5, 1);
+        pageRank.setEdge(5, 1, 1);
+
+        double[] result = pageRank.calculatePageRank(5);
+
+        double sum = 0;
+        for (int i = 1; i <= 5; i++) {
+            sum += result[i];
+        }
+
+        // Sum after 2 iterations with default damping factor
+        assertEquals(2.11, sum, EPSILON);
+    }
+
+    /**
+     * Test graph with isolated node (no incoming or outgoing links)
+     */
+    @Test
+    void testGraphWithIsolatedNode() {
+        PageRank pageRank = new PageRank(3);
+
+        // Node 1 and 2 are connected, Node 3 is isolated
+        pageRank.setEdge(1, 2, 1);
+        pageRank.setEdge(2, 1, 1);
+
+        double[] result = pageRank.calculatePageRank(3);
+
+        assertNotNull(result);
+        // Isolated node should have some PageRank due to damping factor
+        assertEquals(0.15, result[3], EPSILON);
+    }
+
+    /**
+     * Test verbose mode (should not throw exception)
+     */
+    @Test
+    void testVerboseMode() {
+        PageRank pageRank = new PageRank(2);
+
+        pageRank.setEdge(1, 2, 1);
+
+        // This should execute without throwing an exception
+        double[] result = pageRank.calculatePageRank(2, 0.85, 2, true);
+
+        assertNotNull(result);
+    }
+}

From 14a23b709a27eb47644ebc35e8f386827cf110d3 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Sun, 12 Oct 2025 14:35:30 +0530
Subject: [PATCH 1006/1338] refactor: Enhance docs, code, add tests in
 `LowestBasePalindrome` (#6648)

---
 .../others/LowestBasePalindrome.java          | 97 ++++++++++++++++---
 .../others/LowestBasePalindromeTest.java      | 64 ++++++++++--
 2 files changed, 135 insertions(+), 26 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java b/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
index 76d1ed4aba1d..a3ca8d6f6db8 100644
--- a/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
+++ b/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
@@ -4,8 +4,26 @@
 import java.util.List;
 
 /**
- * @brief Class for finding the lowest base in which a given integer is a palindrome.
-     cf. https://oeis.org/A016026
+ * Utility class for finding the lowest base in which a given integer is a
+ * palindrome.
+ * <p>
+ * A number is a palindrome in a given base if its representation in that base
+ * reads the same
+ * forwards and backwards. For example, 15 in base 2 is 1111, which is
+ * palindromic.
+ * This class provides methods to check palindromic properties and find the
+ * smallest base
+ * where a number becomes palindromic.
+ * </p>
+ * <p>
+ * Example: The number 15 in base 2 is represented as [1,1,1,1], which is
+ * palindromic.
+ * The number 10 in base 3 is represented as [1,0,1], which is also palindromic.
+ * </p>
+ *
+ * @see <a href="https://oeis.org/A016026">OEIS A016026 - Smallest base in which
+ *      n is palindromic</a>
+ * @author TheAlgorithms Contributors
  */
 public final class LowestBasePalindrome {
     private LowestBasePalindrome() {
@@ -37,12 +55,18 @@ private static void checkNumber(int number) {
 
     /**
      * Computes the digits of a given number in a specified base.
+     * <p>
+     * The digits are returned in reverse order (least significant digit first).
+     * For example, the number 13 in base 2 produces [1,0,1,1] representing 1101 in
+     * binary.
+     * </p>
      *
-     * @param number the number to be converted
-     * @param base the base to be used for the conversion
-     * @return a list of digits representing the number in the given base, with the most
-     *         significant digit at the end of the list
-     * @throws IllegalArgumentException if the number is negative or the base is less than 2
+     * @param number the number to be converted (must be non-negative)
+     * @param base   the base to be used for the conversion (must be greater than 1)
+     * @return a list of digits representing the number in the given base, with the
+     *         least significant digit at the beginning of the list
+     * @throws IllegalArgumentException if the number is negative or the base is
+     *                                  less than 2
      */
     public static List<Integer> computeDigitsInBase(int number, int base) {
         checkNumber(number);
@@ -58,6 +82,10 @@ public static List<Integer> computeDigitsInBase(int number, int base) {
 
     /**
      * Checks if a list of integers is palindromic.
+     * <p>
+     * A list is palindromic if it reads the same forwards and backwards.
+     * For example, [1,2,1] is palindromic, but [1,2,3] is not.
+     * </p>
      *
      * @param list the list of integers to be checked
      * @return {@code true} if the list is a palindrome, {@code false} otherwise
@@ -73,12 +101,29 @@ public static boolean isPalindromic(List<Integer> list) {
     }
 
     /**
-     * Checks if the representation of a given number in a specified base is palindromic.
+     * Checks if the representation of a given number in a specified base is
+     * palindromic.
+     * <p>
+     * This method first validates the input, then applies optimization: if the
+     * number
+     * ends with 0 in the given base (i.e., divisible by the base), it cannot be
+     * palindromic
+     * as palindromes cannot start with 0.
+     * </p>
+     * <p>
+     * Examples:
+     * - 101 in base 10 is palindromic (101)
+     * - 15 in base 2 is palindromic (1111)
+     * - 10 in base 3 is palindromic (101)
+     * </p>
      *
-     * @param number the number to be checked
-     * @param base the base in which the number will be represented
-     * @return {@code true} if the number is palindromic in the specified base, {@code false} otherwise
-     * @throws IllegalArgumentException if the number is negative or the base is less than 2
+     * @param number the number to be checked (must be non-negative)
+     * @param base   the base in which the number will be represented (must be
+     *               greater than 1)
+     * @return {@code true} if the number is palindromic in the specified base,
+     *         {@code false} otherwise
+     * @throws IllegalArgumentException if the number is negative or the base is
+     *                                  less than 2
      */
     public static boolean isPalindromicInBase(int number, int base) {
         checkNumber(number);
@@ -89,7 +134,8 @@ public static boolean isPalindromicInBase(int number, int base) {
         }
 
         if (number % base == 0) {
-            // If the last digit of the number in the given base is 0, it can't be palindromic
+            // If the last digit of the number in the given base is 0, it can't be
+            // palindromic
             return false;
         }
 
@@ -97,10 +143,29 @@ public static boolean isPalindromicInBase(int number, int base) {
     }
 
     /**
-     * Finds the smallest base in which the representation of a given number is palindromic.
+     * Finds the smallest base in which the representation of a given number is
+     * palindromic.
+     * <p>
+     * This method iteratively checks bases starting from 2 until it finds one where
+     * the number is palindromic. For any number n ≥ 2, the number is always
+     * palindromic
+     * in base n-1 (represented as [1, 1]), so this algorithm is guaranteed to
+     * terminate.
+     * </p>
+     * <p>
+     * Time Complexity: O(n * log(n)) in the worst case, where we check each base
+     * and
+     * convert the number to that base.
+     * </p>
+     * <p>
+     * Examples:
+     * - lowestBasePalindrome(15) returns 2 (15 in base 2 is 1111)
+     * - lowestBasePalindrome(10) returns 3 (10 in base 3 is 101)
+     * - lowestBasePalindrome(11) returns 10 (11 in base 10 is 11)
+     * </p>
      *
-     * @param number the number to be checked
-     * @return the smallest base in which the number is a palindrome
+     * @param number the number to be checked (must be non-negative)
+     * @return the smallest base in which the number is a palindrome (base ≥ 2)
      * @throws IllegalArgumentException if the number is negative
      */
     public static int lowestBasePalindrome(int number) {
diff --git a/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java b/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java
index 1014f39a26bc..7c3ce6635aa0 100644
--- a/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java
+++ b/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java
@@ -1,53 +1,80 @@
 package com.thealgorithms.others;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
+/**
+ * Comprehensive test suite for {@link LowestBasePalindrome}.
+ * Tests all public methods including edge cases and exception handling.
+ *
+ * @author TheAlgorithms Contributors
+ */
 public class LowestBasePalindromeTest {
 
     @ParameterizedTest
     @MethodSource("provideListsForIsPalindromicPositive")
     public void testIsPalindromicPositive(List<Integer> list) {
-        assertTrue(LowestBasePalindrome.isPalindromic(list));
+        Assertions.assertTrue(LowestBasePalindrome.isPalindromic(list));
     }
 
     @ParameterizedTest
     @MethodSource("provideListsForIsPalindromicNegative")
     public void testIsPalindromicNegative(List<Integer> list) {
-        assertFalse(LowestBasePalindrome.isPalindromic(list));
+        Assertions.assertFalse(LowestBasePalindrome.isPalindromic(list));
     }
 
     @ParameterizedTest
     @MethodSource("provideNumbersAndBasesForIsPalindromicInBasePositive")
     public void testIsPalindromicInBasePositive(int number, int base) {
-        assertTrue(LowestBasePalindrome.isPalindromicInBase(number, base));
+        Assertions.assertTrue(LowestBasePalindrome.isPalindromicInBase(number, base));
     }
 
     @ParameterizedTest
     @MethodSource("provideNumbersAndBasesForIsPalindromicInBaseNegative")
     public void testIsPalindromicInBaseNegative(int number, int base) {
-        assertFalse(LowestBasePalindrome.isPalindromicInBase(number, base));
+        Assertions.assertFalse(LowestBasePalindrome.isPalindromicInBase(number, base));
     }
 
     @ParameterizedTest
     @MethodSource("provideNumbersAndBasesForExceptions")
     public void testIsPalindromicInBaseThrowsException(int number, int base) {
-        org.junit.jupiter.api.Assertions.assertThrows(IllegalArgumentException.class, () -> LowestBasePalindrome.isPalindromicInBase(number, base));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> LowestBasePalindrome.isPalindromicInBase(number, base));
     }
 
     @ParameterizedTest
     @MethodSource("provideNumbersForLowestBasePalindrome")
     public void testLowestBasePalindrome(int number, int expectedBase) {
-        assertEquals(expectedBase, LowestBasePalindrome.lowestBasePalindrome(number));
+        Assertions.assertEquals(expectedBase, LowestBasePalindrome.lowestBasePalindrome(number));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideNumbersForComputeDigitsInBase")
+    public void testComputeDigitsInBase(int number, int base, List<Integer> expectedDigits) {
+        Assertions.assertEquals(expectedDigits, LowestBasePalindrome.computeDigitsInBase(number, base));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideInvalidNumbersForComputeDigits")
+    public void testComputeDigitsInBaseThrowsExceptionForNegativeNumber(int number, int base) {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> LowestBasePalindrome.computeDigitsInBase(number, base));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideInvalidBasesForComputeDigits")
+    public void testComputeDigitsInBaseThrowsExceptionForInvalidBase(int number, int base) {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> LowestBasePalindrome.computeDigitsInBase(number, base));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideNegativeNumbersForLowestBasePalindrome")
+    public void testLowestBasePalindromeThrowsExceptionForNegativeNumber(int number) {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> LowestBasePalindrome.lowestBasePalindrome(number));
     }
 
     private static Stream<Arguments> provideListsForIsPalindromicPositive() {
@@ -74,4 +101,21 @@ private static Stream<Arguments> provideNumbersForLowestBasePalindrome() {
         return Stream.of(Arguments.of(0, 2), Arguments.of(1, 2), Arguments.of(2, 3), Arguments.of(3, 2), Arguments.of(10, 3), Arguments.of(11, 10), Arguments.of(15, 2), Arguments.of(39, 12), Arguments.of(44, 10), Arguments.of(58, 28), Arguments.of(69, 22), Arguments.of(79, 78), Arguments.of(87, 28),
             Arguments.of(90, 14), Arguments.of(5591, 37), Arguments.of(5895, 130), Arguments.of(9950, 198), Arguments.of(9974, 4986));
     }
+
+    private static Stream<Arguments> provideNumbersForComputeDigitsInBase() {
+        return Stream.of(Arguments.of(0, 2, new ArrayList<>()), Arguments.of(5, 2, Arrays.asList(1, 0, 1)), Arguments.of(13, 2, Arrays.asList(1, 0, 1, 1)), Arguments.of(10, 3, Arrays.asList(1, 0, 1)), Arguments.of(15, 2, Arrays.asList(1, 1, 1, 1)), Arguments.of(101, 10, Arrays.asList(1, 0, 1)),
+            Arguments.of(255, 16, Arrays.asList(15, 15)), Arguments.of(100, 10, Arrays.asList(0, 0, 1)));
+    }
+
+    private static Stream<Arguments> provideInvalidNumbersForComputeDigits() {
+        return Stream.of(Arguments.of(-1, 2), Arguments.of(-10, 10), Arguments.of(-100, 5));
+    }
+
+    private static Stream<Arguments> provideInvalidBasesForComputeDigits() {
+        return Stream.of(Arguments.of(10, 1), Arguments.of(5, 0), Arguments.of(100, -1));
+    }
+
+    private static Stream<Arguments> provideNegativeNumbersForLowestBasePalindrome() {
+        return Stream.of(Arguments.of(-1), Arguments.of(-10), Arguments.of(-100));
+    }
 }

From 9a907c8843dcfdda171506caae9aa53e517d601f Mon Sep 17 00:00:00 2001
From: Priyanshu Kumar Singh <priyanshu1303d@gmail.com>
Date: Mon, 13 Oct 2025 00:55:21 +0530
Subject: [PATCH 1007/1338] [FEAT] Implement Dials Algorithm (Graph) (#6679)

[FEAT] Implement Dials Algorithm(Graph)

Co-authored-by: Priyanshu1303d <priyanshu130d@gmail.com>
---
 .../datastructures/graphs/DialsAlgorithm.java | 114 ++++++++++++++++++
 .../graphs/DialsAlgorithmTest.java            |  88 ++++++++++++++
 2 files changed, 202 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/DialsAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/DialsAlgorithmTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/DialsAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/DialsAlgorithm.java
new file mode 100644
index 000000000000..da3fba88c618
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/DialsAlgorithm.java
@@ -0,0 +1,114 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * An implementation of Dial's Algorithm for the single-source shortest path problem.
+ * This algorithm is an optimization of Dijkstra's algorithm and is particularly
+ * efficient for graphs with small, non-negative integer edge weights.
+ *
+ * It uses a bucket queue (implemented here as a List of HashSets) to store vertices,
+ * where each bucket corresponds to a specific distance from the source. This is more
+ * efficient than a standard priority queue when the range of edge weights is small.
+ *
+ * Time Complexity: O(E + W * V), where E is the number of edges, V is the number
+ * of vertices, and W is the maximum weight of any edge.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Dijkstra%27s_algorithm#Dial's_algorithm">Wikipedia - Dial's Algorithm</a>
+ */
+public final class DialsAlgorithm {
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private DialsAlgorithm() {
+    }
+    /**
+     * Represents an edge in the graph, connecting to a destination vertex with a given weight.
+     */
+    public static class Edge {
+        private final int destination;
+        private final int weight;
+
+        public Edge(int destination, int weight) {
+            this.destination = destination;
+            this.weight = weight;
+        }
+
+        public int getDestination() {
+            return destination;
+        }
+
+        public int getWeight() {
+            return weight;
+        }
+    }
+    /**
+     * Finds the shortest paths from a source vertex to all other vertices in a weighted graph.
+     *
+     * @param graph The graph represented as an adjacency list.
+     * @param source The source vertex to start from (0-indexed).
+     * @param maxEdgeWeight The maximum weight of any single edge in the graph.
+     * @return An array of integers where the value at each index `i` is the
+     * shortest distance from the source to vertex `i`. Unreachable vertices
+     * will have a value of Integer.MAX_VALUE.
+     * @throws IllegalArgumentException if the source vertex is out of bounds.
+     */
+    public static int[] run(List<List<Edge>> graph, int source, int maxEdgeWeight) {
+        int numVertices = graph.size();
+        if (source < 0 || source >= numVertices) {
+            throw new IllegalArgumentException("Source vertex is out of bounds.");
+        }
+
+        // Initialize distances array
+        int[] distances = new int[numVertices];
+        Arrays.fill(distances, Integer.MAX_VALUE);
+        distances[source] = 0;
+
+        // The bucket queue. Size is determined by the max possible path length.
+        int maxPathWeight = maxEdgeWeight * (numVertices > 0 ? numVertices - 1 : 0);
+        List<Set<Integer>> buckets = new ArrayList<>(maxPathWeight + 1);
+        for (int i = 0; i <= maxPathWeight; i++) {
+            buckets.add(new HashSet<>());
+        }
+
+        // Add the source vertex to the first bucket
+        buckets.get(0).add(source);
+
+        // Process buckets in increasing order of distance
+        for (int d = 0; d <= maxPathWeight; d++) {
+            // Process all vertices in the current bucket
+            while (!buckets.get(d).isEmpty()) {
+                // Get and remove a vertex from the current bucket
+                int u = buckets.get(d).iterator().next();
+                buckets.get(d).remove(u);
+
+                // If we've found a shorter path already, skip
+                if (d > distances[u]) {
+                    continue;
+                }
+
+                // Relax all adjacent edges
+                for (Edge edge : graph.get(u)) {
+                    int v = edge.getDestination();
+                    int weight = edge.getWeight();
+
+                    // If a shorter path to v is found
+                    if (distances[u] != Integer.MAX_VALUE && distances[u] + weight < distances[v]) {
+                        // If v was already in a bucket, remove it from the old one
+                        if (distances[v] != Integer.MAX_VALUE) {
+                            buckets.get(distances[v]).remove(v);
+                        }
+                        // Update distance and move v to the new bucket
+                        distances[v] = distances[u] + weight;
+                        buckets.get(distances[v]).add(v);
+                    }
+                }
+            }
+        }
+        return distances;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/DialsAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/DialsAlgorithmTest.java
new file mode 100644
index 000000000000..2350455d4329
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/DialsAlgorithmTest.java
@@ -0,0 +1,88 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+final class DialsAlgorithmTest {
+
+    private List<List<DialsAlgorithm.Edge>> graph;
+    private static final int NUM_VERTICES = 6;
+    private static final int MAX_EDGE_WEIGHT = 10;
+
+    @BeforeEach
+    void setUp() {
+        graph = new ArrayList<>();
+        for (int i = 0; i < NUM_VERTICES; i++) {
+            graph.add(new ArrayList<>());
+        }
+    }
+
+    private void addEdge(int u, int v, int weight) {
+        graph.get(u).add(new DialsAlgorithm.Edge(v, weight));
+    }
+
+    @Test
+    @DisplayName("Test with a simple connected graph")
+    void testSimpleGraph() {
+        // Build graph from a standard example
+        addEdge(0, 1, 2);
+        addEdge(0, 2, 4);
+        addEdge(1, 2, 1);
+        addEdge(1, 3, 7);
+        addEdge(2, 4, 3);
+        addEdge(3, 5, 1);
+        addEdge(4, 3, 2);
+        addEdge(4, 5, 5);
+
+        int[] expectedDistances = {0, 2, 3, 8, 6, 9};
+        int[] actualDistances = DialsAlgorithm.run(graph, 0, MAX_EDGE_WEIGHT);
+        assertArrayEquals(expectedDistances, actualDistances);
+    }
+
+    @Test
+    @DisplayName("Test with a disconnected node")
+    void testDisconnectedNode() {
+        addEdge(0, 1, 5);
+        addEdge(1, 2, 5);
+        // Node 3, 4, 5 are disconnected
+
+        int[] expectedDistances = {0, 5, 10, Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE};
+        int[] actualDistances = DialsAlgorithm.run(graph, 0, MAX_EDGE_WEIGHT);
+        assertArrayEquals(expectedDistances, actualDistances);
+    }
+
+    @Test
+    @DisplayName("Test with source as destination")
+    void testSourceIsDestination() {
+        addEdge(0, 1, 10);
+        int[] expectedDistances = {0, 10, Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE};
+        // Run with source 0
+        int[] actualDistances = DialsAlgorithm.run(graph, 0, MAX_EDGE_WEIGHT);
+        assertArrayEquals(expectedDistances, actualDistances);
+    }
+
+    @Test
+    @DisplayName("Test graph with multiple paths to a node")
+    void testMultiplePaths() {
+        addEdge(0, 1, 10);
+        addEdge(0, 2, 3);
+        addEdge(2, 1, 2); // Shorter path to 1 is via 2 (3+2=5)
+
+        int[] expectedDistances = {0, 5, 3, Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE};
+        int[] actualDistances = DialsAlgorithm.run(graph, 0, MAX_EDGE_WEIGHT);
+        assertArrayEquals(expectedDistances, actualDistances);
+    }
+
+    @Test
+    @DisplayName("Test with an invalid source vertex")
+    void testInvalidSource() {
+        assertThrows(IllegalArgumentException.class, () -> DialsAlgorithm.run(graph, -1, MAX_EDGE_WEIGHT));
+        assertThrows(IllegalArgumentException.class, () -> DialsAlgorithm.run(graph, NUM_VERTICES, MAX_EDGE_WEIGHT));
+    }
+}

From 74ddea6747808f563189c175c47611286a09ae1e Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 13 Oct 2025 01:34:32 +0530
Subject: [PATCH 1008/1338] refactor: Enhance docs, code, add tests in
 `KrishnaMurthyNumber` (#6742)

* refactor: Enhance docs, code, add tests in `KrishnaMurthyNumber`

* Lint
---
 .../maths/KrishnamurthyNumber.java            | 60 ++++++++-----
 .../thealgorithms/others/Krishnamurthy.java   | 38 --------
 .../maths/KrishnamurthyNumberTest.java        | 86 ++++++++++++++++---
 3 files changed, 111 insertions(+), 73 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/others/Krishnamurthy.java

diff --git a/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java b/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
index 03f18aca786f..a00ef7e3b15d 100644
--- a/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
+++ b/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java
@@ -3,10 +3,25 @@
 /**
  * Utility class for checking if a number is a Krishnamurthy number.
  *
- * A Krishnamurthy number (also known as a Strong number) is a number whose sum of the factorials of its digits is equal to the number itself.
+ * <p>
+ * A Krishnamurthy number (also known as a Strong number or Factorion) is a
+ * number
+ * whose sum of the factorials of its digits is equal to the number itself.
+ * </p>
  *
- * For example, 145 is a Krishnamurthy number because 1! + 4! + 5! = 1 + 24 + 120 = 145.
+ * <p>
+ * For example, 145 is a Krishnamurthy number because 1! + 4! + 5! = 1 + 24 +
+ * 120 = 145.
+ * </p>
+ *
+ * <p>
+ * The only Krishnamurthy numbers in base 10 are: 1, 2, 145, and 40585.
+ * </p>
+ *
+ * <p>
  * <b>Example usage:</b>
+ * </p>
+ *
  * <pre>
  * boolean isKrishnamurthy = KrishnamurthyNumber.isKrishnamurthy(145);
  * System.out.println(isKrishnamurthy); // Output: true
@@ -14,40 +29,43 @@
  * isKrishnamurthy = KrishnamurthyNumber.isKrishnamurthy(123);
  * System.out.println(isKrishnamurthy); // Output: false
  * </pre>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Factorion">Factorion
+ *      (Wikipedia)</a>
  */
 public final class KrishnamurthyNumber {
 
+    // Pre-computed factorials for digits 0-9 to improve performance
+    private static final int[] FACTORIALS = {1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880};
+
     private KrishnamurthyNumber() {
     }
 
     /**
      * Checks if a number is a Krishnamurthy number.
      *
-     * @param n The number to check
+     * <p>
+     * A number is a Krishnamurthy number if the sum of the factorials of its digits
+     * equals the number itself.
+     * </p>
+     *
+     * @param n the number to check
      * @return true if the number is a Krishnamurthy number, false otherwise
      */
     public static boolean isKrishnamurthy(int n) {
-        int tmp = n;
-        int s = 0;
-
         if (n <= 0) {
             return false;
-        } else {
-            while (n != 0) {
-                // initialising the variable fact that will store the factorials of the digits
-                int fact = 1;
-                // computing factorial of each digit
-                for (int i = 1; i <= n % 10; i++) {
-                    fact = fact * i;
-                }
-                // computing the sum of the factorials
-                s = s + fact;
-                // discarding the digit for which factorial has been calculated
-                n = n / 10;
-            }
+        }
 
-            // evaluating if sum of the factorials of the digits equals the number itself
-            return tmp == s;
+        int original = n;
+        int sum = 0;
+
+        while (n != 0) {
+            int digit = n % 10;
+            sum = sum + FACTORIALS[digit];
+            n = n / 10;
         }
+
+        return sum == original;
     }
 }
diff --git a/src/main/java/com/thealgorithms/others/Krishnamurthy.java b/src/main/java/com/thealgorithms/others/Krishnamurthy.java
deleted file mode 100644
index 8e5ba7c6f1c7..000000000000
--- a/src/main/java/com/thealgorithms/others/Krishnamurthy.java
+++ /dev/null
@@ -1,38 +0,0 @@
-package com.thealgorithms.others;
-
-import java.util.Scanner;
-
-final class Krishnamurthy {
-    private Krishnamurthy() {
-    }
-
-    static int fact(int n) {
-        int i;
-        int p = 1;
-        for (i = n; i >= 1; i--) {
-            p = p * i;
-        }
-        return p;
-    }
-
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        int a;
-        int b;
-        int s = 0;
-        System.out.print("Enter the number : ");
-        a = sc.nextInt();
-        int n = a;
-        while (a > 0) {
-            b = a % 10;
-            s = s + fact(b);
-            a = a / 10;
-        }
-        if (s == n) {
-            System.out.print(n + " is a krishnamurthy number");
-        } else {
-            System.out.print(n + " is not a krishnamurthy number");
-        }
-        sc.close();
-    }
-}
diff --git a/src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java b/src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java
index 595acde2b5d8..3c9d4f886b3d 100644
--- a/src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java
@@ -6,57 +6,115 @@
 import org.junit.jupiter.api.Test;
 
 /**
- * Unit tests for the KrishnamurthyNumber class.
+ * Unit tests for the {@link KrishnamurthyNumber} class.
  */
-public class KrishnamurthyNumberTest {
+class KrishnamurthyNumberTest {
 
     /**
-     * Test the isKrishnamurthy method with a known Krishnamurthy number.
+     * Test with known Krishnamurthy number 145.
+     * 1! + 4! + 5! = 1 + 24 + 120 = 145
      */
     @Test
-    public void testIsKrishnamurthyTrue() {
+    void testIsKrishnamurthyWith145() {
         assertTrue(KrishnamurthyNumber.isKrishnamurthy(145));
     }
 
     /**
-     * Test the isKrishnamurthy method with a number that is not a Krishnamurthy number.
+     * Test with a number that is not a Krishnamurthy number.
      */
     @Test
-    public void testIsKrishnamurthyFalse() {
+    void testIsKrishnamurthyWithNonKrishnamurthyNumber() {
         assertFalse(KrishnamurthyNumber.isKrishnamurthy(123));
     }
 
     /**
-     * Test the isKrishnamurthy method with zero.
+     * Test with zero, which is not a Krishnamurthy number.
      */
     @Test
-    public void testIsKrishnamurthyZero() {
+    void testIsKrishnamurthyWithZero() {
         assertFalse(KrishnamurthyNumber.isKrishnamurthy(0));
     }
 
     /**
-     * Test the isKrishnamurthy method with a negative number.
+     * Test with negative numbers, which cannot be Krishnamurthy numbers.
      */
     @Test
-    public void testIsKrishnamurthyNegative() {
+    void testIsKrishnamurthyWithNegativeNumbers() {
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(-1));
         assertFalse(KrishnamurthyNumber.isKrishnamurthy(-145));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(-100));
     }
 
     /**
-     * Test the isKrishnamurthy method with a single-digit Krishnamurthy number.
+     * Test with single-digit Krishnamurthy numbers.
+     * 1! = 1 and 2! = 2, so both 1 and 2 are Krishnamurthy numbers.
      */
     @Test
-    public void testIsKrishnamurthySingleDigitTrue() {
+    void testIsKrishnamurthyWithSingleDigitKrishnamurthyNumbers() {
         assertTrue(KrishnamurthyNumber.isKrishnamurthy(1));
         assertTrue(KrishnamurthyNumber.isKrishnamurthy(2));
     }
 
     /**
-     * Test the isKrishnamurthy method with a single-digit number that is not a Krishnamurthy number.
+     * Test with single-digit numbers that are not Krishnamurthy numbers.
      */
     @Test
-    public void testIsKrishnamurthySingleDigitFalse() {
+    void testIsKrishnamurthyWithSingleDigitNonKrishnamurthyNumbers() {
         assertFalse(KrishnamurthyNumber.isKrishnamurthy(3));
         assertFalse(KrishnamurthyNumber.isKrishnamurthy(4));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(5));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(6));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(7));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(8));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(9));
+    }
+
+    /**
+     * Test with the largest Krishnamurthy number: 40585.
+     * 4! + 0! + 5! + 8! + 5! = 24 + 1 + 120 + 40320 + 120 = 40585
+     */
+    @Test
+    void testIsKrishnamurthyWithLargestKrishnamurthyNumber() {
+        assertTrue(KrishnamurthyNumber.isKrishnamurthy(40585));
+    }
+
+    /**
+     * Test with various non-Krishnamurthy numbers.
+     */
+    @Test
+    void testIsKrishnamurthyWithVariousNonKrishnamurthyNumbers() {
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(10));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(50));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(100));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(144));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(146));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(150));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(200));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(999));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(1000));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(40584));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(40586));
+    }
+
+    /**
+     * Test with numbers close to known Krishnamurthy numbers.
+     */
+    @Test
+    void testIsKrishnamurthyWithNumbersCloseToKrishnamurthy() {
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(144));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(146));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(40584));
+        assertFalse(KrishnamurthyNumber.isKrishnamurthy(40586));
+    }
+
+    /**
+     * Test with all known Krishnamurthy numbers in base 10.
+     */
+    @Test
+    void testAllKnownKrishnamurthyNumbers() {
+        assertTrue(KrishnamurthyNumber.isKrishnamurthy(1));
+        assertTrue(KrishnamurthyNumber.isKrishnamurthy(2));
+        assertTrue(KrishnamurthyNumber.isKrishnamurthy(145));
+        assertTrue(KrishnamurthyNumber.isKrishnamurthy(40585));
     }
 }

From bc7b65609209d02a7ea08ca6f40691cabb45aae5 Mon Sep 17 00:00:00 2001
From: Shoyeb Ansari <shoyebff45@gmail.com>
Date: Mon, 13 Oct 2025 02:16:12 +0530
Subject: [PATCH 1009/1338] feat: added TwoSat solutions with Tests, also
 updated Directory.md (#6756)

* feat: added TwoSat solutions and Tests and also updated Directory.md

* added reference urls to the article related to the 2-SAT

* Fix generic type warnings in TwoSat.java

* maven build fix: added rawtypes in SuppressWarnings

* fixed  checkstyle error

* fix: Sorted import order

---------

Co-authored-by: a <alexanderklmn@gmail.com>
---
 DIRECTORY.md                                  |   1 +
 .../datastructures/graphs/TwoSat.java         | 265 ++++++++++++++++++
 .../datastructures/graphs/TwoSatTest.java     | 125 +++++++++
 3 files changed, 391 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/TwoSat.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/TwoSatTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b311b10fa177..ff56d16db947 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -173,6 +173,7 @@
             - 📄 [TarjansAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java)
             - 📄 [UndirectedAdjacencyListGraph](src/main/java/com/thealgorithms/datastructures/graphs/UndirectedAdjacencyListGraph.java)
             - 📄 [WelshPowell](src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java)
+            - 📄 [TwoSat](src/main/java/com/thealgorithms/datastructures/graphs/TwoSat.java)
           - 📁 **hashmap**
             - 📁 **hashing**
               - 📄 [GenericHashMapUsingArray](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/TwoSat.java b/src/main/java/com/thealgorithms/datastructures/graphs/TwoSat.java
new file mode 100644
index 000000000000..835e3880428f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/TwoSat.java
@@ -0,0 +1,265 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Stack;
+
+/**
+ * This class implements a solution to the 2-SAT (2-Satisfiability) problem
+ * using Kosaraju's algorithm to find strongly connected components (SCCs)
+ * in the implication graph.
+ *
+ * <p>
+ * <strong>Brief Idea:</strong>
+ * </p>
+ *
+ * <pre>
+ * 1. From each clause (a ∨ b), we can derive implications:
+ *      (¬a → b) and (¬b → a)
+ *
+ * 2. We construct an implication graph using these implications.
+ *
+ * 3. For each variable x, its negation ¬x is also represented as a node.
+ *    If x and ¬x belong to the same SCC, the expression is unsatisfiable.
+ *
+ * 4. Otherwise, we assign truth values based on the SCC order:
+ *    If SCC(x) > SCC(¬x), then x = true; otherwise, x = false.
+ * </pre>
+ *
+ * <p>
+ * <strong>Complexities:</strong>
+ * </p>
+ * <ul>
+ * <li>Time Complexity: O(n + m)</li>
+ * <li>Space Complexity: O(n + m)</li>
+ * </ul>
+ * where {@code n} is the number of variables and {@code m} is the number of
+ * clauses.
+ *
+ * <p>
+ * <strong>Usage Example:</strong>
+ * </p>
+ *
+ * <pre>
+ * TwoSat twoSat = new TwoSat(5); // Initialize with 5 variables: x1, x2, x3, x4, x5
+ *
+ * // Add clauses
+ * twoSat.addClause(1, false, 2, false); // (x1 ∨ x2)
+ * twoSat.addClause(3, true, 2, false); // (¬x3 ∨ x2)
+ * twoSat.addClause(4, false, 5, true); // (x4 ∨ ¬x5)
+ *
+ * twoSat.solve(); // Solve the problem
+ *
+ * if (twoSat.isSolutionExists()) {
+ *     boolean[] solution = twoSat.getSolutions();
+ *     for (int i = 1; i <= 5; i++) {
+ *         System.out.println("x" + i + " = " + solution[i]);
+ *     }
+ * }
+ * </pre>
+ * <p><strong>Reference</strong></p>
+ * <a href="https://cp-algorithms.com/graph/2SAT.html">CP Algorithm</a> <br></br>
+ * <a href="https://en.wikipedia.org/wiki/2-satisfiability">Wikipedia - 2 SAT</a>
+ * @author Shoyeb Ansari
+ *
+ * @see Kosaraju
+ */
+class TwoSat {
+
+    /** Number of variables in the boolean expression. */
+    private final int numberOfVariables;
+
+    /** Implication graph built from the boolean clauses. */
+    private final ArrayList<Integer>[] graph;
+
+    /** Transposed implication graph used in Kosaraju's algorithm. */
+    private final ArrayList<Integer>[] graphTranspose;
+
+    /** Stores one valid truth assignment for all variables (1-indexed). */
+    private final boolean[] variableAssignments;
+
+    /** Indicates whether a valid solution exists. */
+    private boolean hasSolution = true;
+
+    /** Tracks whether the {@code solve()} method has been called. */
+    private boolean isSolved = false;
+
+    /**
+     * Initializes the TwoSat solver with the given number of variables.
+     *
+     * @param numberOfVariables the number of boolean variables
+     * @throws IllegalArgumentException if the number of variables is negative
+     */
+    @SuppressWarnings({"unchecked", "rawtypes"})
+    TwoSat(int numberOfVariables) {
+        if (numberOfVariables < 0) {
+            throw new IllegalArgumentException("Number of variables cannot be negative.");
+        }
+        this.numberOfVariables = numberOfVariables;
+        int n = 2 * numberOfVariables + 1;
+
+        graph = (ArrayList<Integer>[]) new ArrayList[n];
+        graphTranspose = (ArrayList<Integer>[]) new ArrayList[n];
+        for (int i = 0; i < n; i++) {
+            graph[i] = new ArrayList<>();
+            graphTranspose[i] = new ArrayList<>();
+        }
+        variableAssignments = new boolean[numberOfVariables + 1];
+    }
+
+    /**
+     * Adds a clause of the form (a ∨ b) to the boolean expression.
+     *
+     * <p>
+     * Example: To add (¬x₁ ∨ x₂), call:
+     * </p>
+     *
+     * <pre>{@code
+     * addClause(1, true, 2, false);
+     * }</pre>
+     *
+     * @param a         the first variable (1 ≤ a ≤ numberOfVariables)
+     * @param isNegateA {@code true} if variable {@code a} is negated
+     * @param b         the second variable (1 ≤ b ≤ numberOfVariables)
+     * @param isNegateB {@code true} if variable {@code b} is negated
+     * @throws IllegalArgumentException if {@code a} or {@code b} are out of range
+     */
+    void addClause(int a, boolean isNegateA, int b, boolean isNegateB) {
+        if (a <= 0 || a > numberOfVariables) {
+            throw new IllegalArgumentException("Variable number must be between 1 and " + numberOfVariables);
+        }
+        if (b <= 0 || b > numberOfVariables) {
+            throw new IllegalArgumentException("Variable number must be between 1 and " + numberOfVariables);
+        }
+
+        a = isNegateA ? negate(a) : a;
+        b = isNegateB ? negate(b) : b;
+        int notA = negate(a);
+        int notB = negate(b);
+
+        // Add implications: (¬a → b) and (¬b → a)
+        graph[notA].add(b);
+        graph[notB].add(a);
+
+        // Build transpose graph
+        graphTranspose[b].add(notA);
+        graphTranspose[a].add(notB);
+    }
+
+    /**
+     * Solves the 2-SAT problem using Kosaraju's algorithm to find SCCs
+     * and determines whether a satisfying assignment exists.
+     */
+    void solve() {
+        isSolved = true;
+        int n = 2 * numberOfVariables + 1;
+
+        boolean[] visited = new boolean[n];
+        int[] component = new int[n];
+        Stack<Integer> topologicalOrder = new Stack<>();
+
+        // Step 1: Perform DFS to get topological order
+        for (int i = 1; i < n; i++) {
+            if (!visited[i]) {
+                dfsForTopologicalOrder(i, visited, topologicalOrder);
+            }
+        }
+
+        Arrays.fill(visited, false);
+        int sccId = 0;
+
+        // Step 2: Find SCCs on transposed graph
+        while (!topologicalOrder.isEmpty()) {
+            int node = topologicalOrder.pop();
+            if (!visited[node]) {
+                dfsForScc(node, visited, component, sccId);
+                sccId++;
+            }
+        }
+
+        // Step 3: Check for contradictions and assign values
+        for (int i = 1; i <= numberOfVariables; i++) {
+            int notI = negate(i);
+            if (component[i] == component[notI]) {
+                hasSolution = false;
+                return;
+            }
+            // If SCC(i) > SCC(¬i), then variable i is true.
+            variableAssignments[i] = component[i] > component[notI];
+        }
+    }
+
+    /**
+     * Returns whether the given boolean formula is satisfiable.
+     *
+     * @return {@code true} if a solution exists; {@code false} otherwise
+     * @throws Error if called before {@link #solve()}
+     */
+    boolean isSolutionExists() {
+        if (!isSolved) {
+            throw new Error("Please call solve() before checking for a solution.");
+        }
+        return hasSolution;
+    }
+
+    /**
+     * Returns one valid assignment of variables that satisfies the boolean formula.
+     *
+     * @return a boolean array where {@code result[i]} represents the truth value of
+     *         variable {@code xᵢ}
+     * @throws Error if called before {@link #solve()} or if no solution exists
+     */
+    boolean[] getSolutions() {
+        if (!isSolved) {
+            throw new Error("Please call solve() before fetching the solution.");
+        }
+        if (!hasSolution) {
+            throw new Error("No satisfying assignment exists for the given expression.");
+        }
+        return variableAssignments.clone();
+    }
+
+    /** Performs DFS to compute topological order. */
+    private void dfsForTopologicalOrder(int u, boolean[] visited, Stack<Integer> topologicalOrder) {
+        visited[u] = true;
+        for (int v : graph[u]) {
+            if (!visited[v]) {
+                dfsForTopologicalOrder(v, visited, topologicalOrder);
+            }
+        }
+        topologicalOrder.push(u);
+    }
+
+    /** Performs DFS on the transposed graph to identify SCCs. */
+    private void dfsForScc(int u, boolean[] visited, int[] component, int sccId) {
+        visited[u] = true;
+        component[u] = sccId;
+        for (int v : graphTranspose[u]) {
+            if (!visited[v]) {
+                dfsForScc(v, visited, component, sccId);
+            }
+        }
+    }
+
+    /**
+     * Returns the index representing the negation of the given variable.
+     *
+     * <p>
+     * Mapping rule:
+     * </p>
+     *
+     * <pre>
+     * For a variable i:
+     *     negate(i) = i + n
+     * For a negated variable (i + n):
+     *     negate(i + n) = i
+     * where n = numberOfVariables
+     * </pre>
+     *
+     * @param a the variable index
+     * @return the index representing its negation
+     */
+    private int negate(int a) {
+        return a <= numberOfVariables ? a + numberOfVariables : a - numberOfVariables;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/TwoSatTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/TwoSatTest.java
new file mode 100644
index 000000000000..15e77b357f83
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/TwoSatTest.java
@@ -0,0 +1,125 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Testcases for 2-SAT.
+ * Please note thea whlie checking for boolean assignments always keep n + 1 elements and the first element should be always false.
+ */
+public class TwoSatTest {
+    private TwoSat twoSat;
+
+    /**
+     * Case 1: Basic satisfiable case.
+     * Simple 3 clauses with consistent assignments.
+     */
+    @Test
+    public void testSatisfiableBasicCase() {
+        twoSat = new TwoSat(5);
+
+        twoSat.addClause(1, false, 2, false); // (x1 ∨ x2)
+        twoSat.addClause(3, true, 2, false); // (¬x3 ∨ x2)
+        twoSat.addClause(4, false, 5, true); // (x4 ∨ ¬x5)
+
+        twoSat.solve();
+
+        assertTrue(twoSat.isSolutionExists(), "Expected solution to exist");
+        boolean[] expected = {false, true, true, true, true, true};
+        assertArrayEquals(expected, twoSat.getSolutions());
+    }
+
+    /**
+     * Case 2: Unsatisfiable due to direct contradiction.
+     * (x1 ∨ x1) ∧ (¬x1 ∨ ¬x1) makes x1 and ¬x1 both required.
+     */
+    @Test
+    public void testUnsatisfiableContradiction() {
+        twoSat = new TwoSat(1);
+
+        twoSat.addClause(1, false, 1, false); // (x1 ∨ x1)
+        twoSat.addClause(1, true, 1, true); // (¬x1 ∨ ¬x1)
+
+        twoSat.solve();
+
+        assertFalse(twoSat.isSolutionExists(), "Expected no solution (contradiction)");
+    }
+
+    /**
+     * Case 3: Single variable, trivially satisfiable.
+     * Only (x1 ∨ x1) exists.
+     */
+    @Test
+    public void testSingleVariableTrivialSatisfiable() {
+        twoSat = new TwoSat(1);
+
+        twoSat.addClause(1, false, 1, false); // (x1 ∨ x1)
+
+        twoSat.solve();
+
+        assertTrue(twoSat.isSolutionExists(), "Expected solution to exist");
+        boolean[] expected = {false, true};
+        assertArrayEquals(expected, twoSat.getSolutions());
+    }
+
+    /**
+     * Case 4: Larger satisfiable system with dependencies.
+     * (x1 ∨ x2), (¬x2 ∨ x3), (¬x3 ∨ x4), (¬x4 ∨ x5)
+     */
+    @Test
+    public void testChainedDependenciesSatisfiable() {
+        twoSat = new TwoSat(5);
+
+        twoSat.addClause(1, false, 2, false);
+        twoSat.addClause(2, true, 3, false);
+        twoSat.addClause(3, true, 4, false);
+        twoSat.addClause(4, true, 5, false);
+
+        twoSat.solve();
+
+        assertTrue(twoSat.isSolutionExists(), "Expected solution to exist");
+        boolean[] solution = twoSat.getSolutions();
+        for (int i = 1; i <= 5; i++) {
+            assertTrue(solution[i], "Expected x" + i + " to be true");
+        }
+    }
+
+    /**
+     * Case 5: Contradiction due to dependency cycle.
+     * (x1 ∨ x2), (¬x1 ∨ ¬x2), (x1 ∨ ¬x2), (¬x1 ∨ x2)
+     * These clauses form a circular dependency making it impossible.
+     */
+    @Test
+    public void testUnsatisfiableCycle() {
+        twoSat = new TwoSat(2);
+
+        twoSat.addClause(1, false, 2, false);
+        twoSat.addClause(1, true, 2, true);
+        twoSat.addClause(1, false, 2, true);
+        twoSat.addClause(1, true, 2, false);
+
+        twoSat.solve();
+
+        assertFalse(twoSat.isSolutionExists(), "Expected no solution due to contradictory cycle");
+    }
+
+    /**
+     * Testcase from CSES
+     */
+    @Test
+    public void test6() {
+        twoSat = new TwoSat(2);
+
+        twoSat.addClause(1, true, 2, false);
+        twoSat.addClause(2, true, 1, false);
+        twoSat.addClause(1, true, 1, true);
+        twoSat.addClause(2, false, 2, false);
+
+        twoSat.solve();
+
+        assertFalse(twoSat.isSolutionExists(), "Expected no solution.");
+    }
+}

From ff9fd2e2e4d7ecdb5c0eb62e15c151b9b346eca0 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 13 Oct 2025 02:21:54 +0530
Subject: [PATCH 1010/1338] refactor: Enhance docs, code, add tests in `Median`
 (#6751)

Co-authored-by: a <alexanderklmn@gmail.com>
---
 .../java/com/thealgorithms/maths/Median.java  |  34 ++++-
 .../com/thealgorithms/maths/MedianTest.java   | 127 +++++++++++++++++-
 2 files changed, 148 insertions(+), 13 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Median.java b/src/main/java/com/thealgorithms/maths/Median.java
index fd2aab84e4e9..5e1a4bc3a8d9 100644
--- a/src/main/java/com/thealgorithms/maths/Median.java
+++ b/src/main/java/com/thealgorithms/maths/Median.java
@@ -3,17 +3,35 @@
 import java.util.Arrays;
 
 /**
- * Wikipedia: https://en.wikipedia.org/wiki/Median
+ * Utility class for calculating the median of an array of integers.
+ * The median is the middle value in a sorted list of numbers. If the list has
+ * an even number
+ * of elements, the median is the average of the two middle values.
+ *
+ * <p>
+ * Time Complexity: O(n log n) due to sorting
+ * <p>
+ * Space Complexity: O(1) if sorting is done in-place
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Median">Median (Wikipedia)</a>
+ * @see <a href=
+ *      "https://www.khanacademy.org/math/statistics-probability/summarizing-quantitative-data/mean-median-basics/a/mean-median-and-mode-review">Mean,
+ *      Median, and Mode Review</a>
  */
 public final class Median {
     private Median() {
     }
 
     /**
-     * Calculate average median
-     * @param values sorted numbers to find median of
-     * @return median of given {@code values}
-     * @throws IllegalArgumentException If the input array is empty or null.
+     * Calculates the median of an array of integers.
+     * The array is sorted internally, so the original order is not preserved.
+     * For arrays with an odd number of elements, returns the middle element.
+     * For arrays with an even number of elements, returns the average of the two
+     * middle elements.
+     *
+     * @param values the array of integers to find the median of (can be unsorted)
+     * @return the median value as a double
+     * @throws IllegalArgumentException if the input array is empty or null
      */
     public static double median(int[] values) {
         if (values == null || values.length == 0) {
@@ -22,6 +40,10 @@ public static double median(int[] values) {
 
         Arrays.sort(values);
         int length = values.length;
-        return length % 2 == 0 ? (values[length / 2] + values[length / 2 - 1]) / 2.0 : values[length / 2];
+        if (length % 2 == 0) {
+            return (values[length / 2] + values[length / 2 - 1]) / 2.0;
+        } else {
+            return values[length / 2];
+        }
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/MedianTest.java b/src/test/java/com/thealgorithms/maths/MedianTest.java
index 560feb695792..f42fe8bb17ee 100644
--- a/src/test/java/com/thealgorithms/maths/MedianTest.java
+++ b/src/test/java/com/thealgorithms/maths/MedianTest.java
@@ -5,40 +5,153 @@
 
 import org.junit.jupiter.api.Test;
 
-public class MedianTest {
+/**
+ * Test class for {@link Median}.
+ * Tests various scenarios including edge cases, odd/even length arrays,
+ * negative values, and unsorted inputs.
+ */
+class MedianTest {
+
     @Test
-    void medianSingleValue() {
+    void testMedianSingleValue() {
         int[] arr = {0};
         assertEquals(0, Median.median(arr));
     }
 
     @Test
-    void medianTwoValues() {
+    void testMedianSinglePositiveValue() {
+        int[] arr = {42};
+        assertEquals(42, Median.median(arr));
+    }
+
+    @Test
+    void testMedianSingleNegativeValue() {
+        int[] arr = {-15};
+        assertEquals(-15, Median.median(arr));
+    }
+
+    @Test
+    void testMedianTwoValues() {
         int[] arr = {1, 2};
         assertEquals(1.5, Median.median(arr));
     }
 
     @Test
-    void medianThreeValues() {
+    void testMedianTwoIdenticalValues() {
+        int[] arr = {5, 5};
+        assertEquals(5.0, Median.median(arr));
+    }
+
+    @Test
+    void testMedianThreeValues() {
         int[] arr = {1, 2, 3};
         assertEquals(2, Median.median(arr));
     }
 
     @Test
-    void medianDecimalValueReturn() {
+    void testMedianThreeUnsortedValues() {
+        int[] arr = {3, 1, 2};
+        assertEquals(2, Median.median(arr));
+    }
+
+    @Test
+    void testMedianDecimalValueReturn() {
         int[] arr = {1, 2, 3, 4, 5, 6, 8, 9};
         assertEquals(4.5, Median.median(arr));
     }
 
     @Test
-    void medianNegativeValues() {
+    void testMedianNegativeValues() {
         int[] arr = {-27, -16, -7, -4, -2, -1};
         assertEquals(-5.5, Median.median(arr));
     }
 
     @Test
-    void medianEmptyArrayThrows() {
+    void testMedianMixedPositiveAndNegativeValues() {
+        int[] arr = {-10, -5, 0, 5, 10};
+        assertEquals(0, Median.median(arr));
+    }
+
+    @Test
+    void testMedianMixedUnsortedValues() {
+        int[] arr = {10, -5, 0, 5, -10};
+        assertEquals(0, Median.median(arr));
+    }
+
+    @Test
+    void testMedianLargeOddArray() {
+        int[] arr = {9, 7, 5, 3, 1, 2, 4, 6, 8};
+        assertEquals(5, Median.median(arr));
+    }
+
+    @Test
+    void testMedianLargeEvenArray() {
+        int[] arr = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100};
+        assertEquals(55.0, Median.median(arr));
+    }
+
+    @Test
+    void testMedianAllSameValues() {
+        int[] arr = {7, 7, 7, 7, 7};
+        assertEquals(7.0, Median.median(arr));
+    }
+
+    @Test
+    void testMedianWithZeros() {
+        int[] arr = {0, 0, 0, 0, 0};
+        assertEquals(0.0, Median.median(arr));
+    }
+
+    @Test
+    void testMedianAlreadySorted() {
+        int[] arr = {1, 2, 3, 4, 5};
+        assertEquals(3, Median.median(arr));
+    }
+
+    @Test
+    void testMedianReverseSorted() {
+        int[] arr = {5, 4, 3, 2, 1};
+        assertEquals(3, Median.median(arr));
+    }
+
+    @Test
+    void testMedianWithDuplicates() {
+        int[] arr = {1, 2, 2, 3, 3, 3, 4};
+        assertEquals(3, Median.median(arr));
+    }
+
+    @Test
+    void testMedianEmptyArrayThrows() {
         int[] arr = {};
         assertThrows(IllegalArgumentException.class, () -> Median.median(arr));
     }
+
+    @Test
+    void testMedianNullArrayThrows() {
+        assertThrows(IllegalArgumentException.class, () -> Median.median(null));
+    }
+
+    @Test
+    void testMedianExtremeValues() {
+        int[] arr = {Integer.MAX_VALUE, Integer.MIN_VALUE};
+        assertEquals(-0.5, Median.median(arr));
+    }
+
+    @Test
+    void testMedianTwoNegativeValues() {
+        int[] arr = {-10, -20};
+        assertEquals(-15.0, Median.median(arr));
+    }
+
+    @Test
+    void testMedianFourValuesEven() {
+        int[] arr = {1, 2, 3, 4};
+        assertEquals(2.5, Median.median(arr));
+    }
+
+    @Test
+    void testMedianFiveValuesOdd() {
+        int[] arr = {10, 20, 30, 40, 50};
+        assertEquals(30.0, Median.median(arr));
+    }
 }

From 297634d05fdd9b90b58c9060229229c0cae6280a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 13 Oct 2025 02:43:14 +0530
Subject: [PATCH 1011/1338] refactor: Enhance docs, code, add tests in
 `KaprekarNumbers` (#6747)

Co-authored-by: a <alexanderklmn@gmail.com>
---
 .../thealgorithms/maths/KaprekarNumbers.java  | 114 ++++++++---
 .../maths/KaprekarNumbersTest.java            | 185 ++++++++++++++----
 2 files changed, 233 insertions(+), 66 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java b/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
index eb9750f9ce08..99842e2f4f5e 100644
--- a/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
+++ b/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java
@@ -4,23 +4,51 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Utility class for identifying and working with Kaprekar Numbers.
+ * <p>
+ * A Kaprekar number is a positive integer with the following property:
+ * If you square it, then split the resulting number into two parts (right part
+ * has same number of
+ * digits as the original number, left part has the remaining digits), and
+ * finally add the two
+ * parts together, you get the original number.
+ * <p>
+ * For example:
+ * <ul>
+ * <li>9: 9² = 81 → 8 + 1 = 9 (Kaprekar number)</li>
+ * <li>45: 45² = 2025 → 20 + 25 = 45 (Kaprekar number)</li>
+ * <li>297: 297² = 88209 → 88 + 209 = 297 (Kaprekar number)</li>
+ * </ul>
+ * <p>
+ * Note: The right part can have leading zeros, but must not be all zeros.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Kaprekar_number">Kaprekar Number
+ *      - Wikipedia</a>
+ * @author TheAlgorithms (https://github.com/TheAlgorithms)
+ */
 public final class KaprekarNumbers {
     private KaprekarNumbers() {
     }
 
-    /* This program demonstrates if a given number is Kaprekar Number or not.
-        Kaprekar Number: A Kaprekar number is an n-digit number which its square can be split into
-       two parts where the right part has n digits and sum of these parts is equal to the original
-       number. */
-
-    // Provides a list of kaprekarNumber in a range
-    public static List<Long> kaprekarNumberInRange(long start, long end) throws Exception {
-        long n = end - start;
-        if (n < 0) {
-            throw new Exception("Invalid range");
+    /**
+     * Finds all Kaprekar numbers within a given range (inclusive).
+     *
+     * @param start the starting number of the range (inclusive)
+     * @param end   the ending number of the range (inclusive)
+     * @return a list of all Kaprekar numbers in the specified range
+     * @throws IllegalArgumentException if start is greater than end or if start is
+     *                                  negative
+     */
+    public static List<Long> kaprekarNumberInRange(long start, long end) {
+        if (start > end) {
+            throw new IllegalArgumentException("Start must be less than or equal to end. Given start: " + start + ", end: " + end);
+        }
+        if (start < 0) {
+            throw new IllegalArgumentException("Start must be non-negative. Given start: " + start);
         }
-        ArrayList<Long> list = new ArrayList<>();
 
+        ArrayList<Long> list = new ArrayList<>();
         for (long i = start; i <= end; i++) {
             if (isKaprekarNumber(i)) {
                 list.add(i);
@@ -30,24 +58,60 @@ public static List<Long> kaprekarNumberInRange(long start, long end) throws Exce
         return list;
     }
 
-    // Checks whether a given number is Kaprekar Number or not
+    /**
+     * Checks whether a given number is a Kaprekar number.
+     * <p>
+     * The algorithm works as follows:
+     * <ol>
+     * <li>Square the number</li>
+     * <li>Split the squared number into two parts: left and right</li>
+     * <li>The right part has the same number of digits as the original number</li>
+     * <li>Add the left and right parts</li>
+     * <li>If the sum equals the original number, it's a Kaprekar number</li>
+     * </ol>
+     * <p>
+     * Special handling is required for numbers whose squares contain zeros.
+     *
+     * @param num the number to check
+     * @return true if the number is a Kaprekar number, false otherwise
+     * @throws IllegalArgumentException if num is negative
+     */
     public static boolean isKaprekarNumber(long num) {
+        if (num < 0) {
+            throw new IllegalArgumentException("Number must be non-negative. Given: " + num);
+        }
+
+        if (num == 0 || num == 1) {
+            return true;
+        }
+
         String number = Long.toString(num);
         BigInteger originalNumber = BigInteger.valueOf(num);
         BigInteger numberSquared = originalNumber.multiply(originalNumber);
-        if (number.length() == numberSquared.toString().length()) {
-            return number.equals(numberSquared.toString());
-        } else {
-            BigInteger leftDigits1 = BigInteger.ZERO;
-            BigInteger leftDigits2;
-            if (numberSquared.toString().contains("0")) {
-                leftDigits1 = new BigInteger(numberSquared.toString().substring(0, numberSquared.toString().indexOf("0")));
-            }
-            leftDigits2 = new BigInteger(numberSquared.toString().substring(0, (numberSquared.toString().length() - number.length())));
-            BigInteger rightDigits = new BigInteger(numberSquared.toString().substring(numberSquared.toString().length() - number.length()));
-            String x = leftDigits1.add(rightDigits).toString();
-            String y = leftDigits2.add(rightDigits).toString();
-            return (number.equals(x)) || (number.equals(y));
+        String squaredStr = numberSquared.toString();
+
+        // Special case: if the squared number has the same length as the original
+        if (number.length() == squaredStr.length()) {
+            return number.equals(squaredStr);
+        }
+
+        // Calculate the split position
+        int splitPos = squaredStr.length() - number.length();
+
+        // Split the squared number into left and right parts
+        String leftPart = squaredStr.substring(0, splitPos);
+        String rightPart = squaredStr.substring(splitPos);
+
+        // Parse the parts as BigInteger (handles empty left part as zero)
+        BigInteger leftNum = leftPart.isEmpty() ? BigInteger.ZERO : new BigInteger(leftPart);
+        BigInteger rightNum = new BigInteger(rightPart);
+
+        // Check if right part is all zeros (invalid for Kaprekar numbers except 1)
+        if (rightNum.equals(BigInteger.ZERO)) {
+            return false;
         }
+
+        // Check if the sum equals the original number
+        return leftNum.add(rightNum).equals(originalNumber);
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java b/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java
index 05e58cf88e22..a3cd7500b30c 100644
--- a/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java
+++ b/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java
@@ -1,85 +1,188 @@
 package com.thealgorithms.maths;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class KaprekarNumbersTest {
+/**
+ * Test class for {@link KaprekarNumbers}.
+ * Tests various Kaprekar numbers and edge cases to ensure full coverage.
+ */
+class KaprekarNumbersTest {
 
     @Test
-    void testFor1() {
+    void testZeroIsKaprekarNumber() {
+        assertTrue(KaprekarNumbers.isKaprekarNumber(0));
+    }
+
+    @Test
+    void testOneIsKaprekarNumber() {
         assertTrue(KaprekarNumbers.isKaprekarNumber(1));
     }
 
     @Test
-    void testFor45() {
+    void testNineIsKaprekarNumber() {
+        // 9^2 = 81, 8 + 1 = 9
+        assertTrue(KaprekarNumbers.isKaprekarNumber(9));
+    }
+
+    @Test
+    void testFortyFiveIsKaprekarNumber() {
+        // 45^2 = 2025, 20 + 25 = 45
         assertTrue(KaprekarNumbers.isKaprekarNumber(45));
     }
 
     @Test
-    void testFor297() {
+    void testFiftyFiveIsKaprekarNumber() {
+        // 55^2 = 3025, 30 + 25 = 55
+        assertTrue(KaprekarNumbers.isKaprekarNumber(55));
+    }
+
+    @Test
+    void testNinetyNineIsKaprekarNumber() {
+        // 99^2 = 9801, 98 + 01 = 99
+        assertTrue(KaprekarNumbers.isKaprekarNumber(99));
+    }
+
+    @Test
+    void testTwoNinetySevenIsKaprekarNumber() {
+        // 297^2 = 88209, 88 + 209 = 297
         assertTrue(KaprekarNumbers.isKaprekarNumber(297));
     }
 
     @Test
-    void testFor2223() {
+    void testSevenZeroThreeIsKaprekarNumber() {
+        // 703^2 = 494209, 494 + 209 = 703
+        assertTrue(KaprekarNumbers.isKaprekarNumber(703));
+    }
+
+    @Test
+    void testNineNineNineIsKaprekarNumber() {
+        // 999^2 = 998001, 998 + 001 = 999
+        assertTrue(KaprekarNumbers.isKaprekarNumber(999));
+    }
+
+    @Test
+    void testTwoTwoTwoThreeIsKaprekarNumber() {
+        // 2223^2 = 4941729, 4941 + 729 = 5670 (not directly obvious)
+        // Actually: 494 + 1729 = 2223
         assertTrue(KaprekarNumbers.isKaprekarNumber(2223));
     }
 
     @Test
-    void testFor857143() {
+    void testEightFiveSevenOneFortyThreeIsKaprekarNumber() {
         assertTrue(KaprekarNumbers.isKaprekarNumber(857143));
     }
 
     @Test
-    void testFor3() {
+    void testTwoIsNotKaprekarNumber() {
+        assertFalse(KaprekarNumbers.isKaprekarNumber(2));
+    }
+
+    @Test
+    void testThreeIsNotKaprekarNumber() {
         assertFalse(KaprekarNumbers.isKaprekarNumber(3));
     }
 
     @Test
-    void testFor26() {
+    void testTenIsNotKaprekarNumber() {
+        assertFalse(KaprekarNumbers.isKaprekarNumber(10));
+    }
+
+    @Test
+    void testTwentySixIsNotKaprekarNumber() {
         assertFalse(KaprekarNumbers.isKaprekarNumber(26));
     }
 
     @Test
-    void testFor98() {
+    void testNinetyEightIsNotKaprekarNumber() {
         assertFalse(KaprekarNumbers.isKaprekarNumber(98));
     }
 
     @Test
-    void testForRangeOfNumber() {
-        try {
-            List<Long> rangedNumbers = KaprekarNumbers.kaprekarNumberInRange(1, 100000);
-            long[] allTheNumbers = {
-                1,
-                9,
-                45,
-                55,
-                99,
-                297,
-                703,
-                999,
-                2223,
-                2728,
-                4950,
-                5050,
-                7272,
-                7777,
-                9999,
-                17344,
-                22222,
-                77778,
-                82656,
-                95121,
-                99999,
-            };
-            for (long i : allTheNumbers) {
-                assert rangedNumbers.contains(i);
-            }
-        } catch (Exception e) {
-            assert false;
-        }
+    void testOneHundredIsNotKaprekarNumber() {
+        assertFalse(KaprekarNumbers.isKaprekarNumber(100));
+    }
+
+    @Test
+    void testNegativeNumberThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> KaprekarNumbers.isKaprekarNumber(-5));
+    }
+
+    @Test
+    void testKaprekarNumbersInSmallRange() {
+        List<Long> result = KaprekarNumbers.kaprekarNumberInRange(1, 10);
+        List<Long> expected = Arrays.asList(1L, 9L);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testKaprekarNumbersInMediumRange() {
+        List<Long> result = KaprekarNumbers.kaprekarNumberInRange(1, 100);
+        List<Long> expected = Arrays.asList(1L, 9L, 45L, 55L, 99L);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testKaprekarNumbersInLargeRange() {
+        List<Long> rangedNumbers = KaprekarNumbers.kaprekarNumberInRange(1, 100000);
+        List<Long> expectedNumbers = Arrays.asList(1L, 9L, 45L, 55L, 99L, 297L, 703L, 999L, 2223L, 2728L, 4950L, 5050L, 7272L, 7777L, 9999L, 17344L, 22222L, 77778L, 82656L, 95121L, 99999L);
+        assertEquals(expectedNumbers, rangedNumbers);
+    }
+
+    @Test
+    void testKaprekarNumbersInSingleElementRange() {
+        List<Long> result = KaprekarNumbers.kaprekarNumberInRange(9, 9);
+        List<Long> expected = Arrays.asList(9L);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testKaprekarNumbersInRangeWithNoKaprekarNumbers() {
+        List<Long> result = KaprekarNumbers.kaprekarNumberInRange(2, 8);
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    void testKaprekarNumbersInRangeStartingFromZero() {
+        List<Long> result = KaprekarNumbers.kaprekarNumberInRange(0, 5);
+        List<Long> expected = Arrays.asList(0L, 1L);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testInvalidRangeThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> KaprekarNumbers.kaprekarNumberInRange(100, 50));
+    }
+
+    @Test
+    void testNegativeStartThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> KaprekarNumbers.kaprekarNumberInRange(-10, 100));
+    }
+
+    @Test
+    void testEmptyRange() {
+        List<Long> result = KaprekarNumbers.kaprekarNumberInRange(10, 44);
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    void testLargeKaprekarNumber() {
+        // Test a larger known Kaprekar number
+        assertTrue(KaprekarNumbers.isKaprekarNumber(142857));
+    }
+
+    @Test
+    void testFourDigitKaprekarNumbers() {
+        // Test some 4-digit Kaprekar numbers
+        assertTrue(KaprekarNumbers.isKaprekarNumber(2728));
+        assertTrue(KaprekarNumbers.isKaprekarNumber(4950));
+        assertTrue(KaprekarNumbers.isKaprekarNumber(5050));
+        assertTrue(KaprekarNumbers.isKaprekarNumber(7272));
     }
 }

From 387ecef310e2a2eccb4cfd917a1581202169457d Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 13 Oct 2025 03:07:24 +0530
Subject: [PATCH 1012/1338] refactor: Enhance docs, code, add tests in
 `KeithNumber` (#6748)

* refactor: Enhance docs, code, add tests in `KeithNumber`

* Fix

---------

Co-authored-by: a <alexanderklmn@gmail.com>
---
 .../com/thealgorithms/maths/KeithNumber.java  | 107 ++++++++----
 .../thealgorithms/maths/KeithNumberTest.java  | 153 ++++++++++++++++++
 2 files changed, 227 insertions(+), 33 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/KeithNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/KeithNumber.java b/src/main/java/com/thealgorithms/maths/KeithNumber.java
index 1756cfbae91b..eb7f800d378f 100644
--- a/src/main/java/com/thealgorithms/maths/KeithNumber.java
+++ b/src/main/java/com/thealgorithms/maths/KeithNumber.java
@@ -4,57 +4,98 @@
 import java.util.Collections;
 import java.util.Scanner;
 
-final class KeithNumber {
+/**
+ * A Keith number is an n-digit positive integer where the sequence formed by
+ * starting with its digits and repeatedly adding the previous n terms,
+ * eventually reaches the number itself.
+ *
+ * <p>
+ * For example:
+ * <ul>
+ * <li>14 is a Keith number: 1, 4, 5, 9, 14</li>
+ * <li>19 is a Keith number: 1, 9, 10, 19</li>
+ * <li>28 is a Keith number: 2, 8, 10, 18, 28</li>
+ * <li>197 is a Keith number: 1, 9, 7, 17, 33, 57, 107, 197</li>
+ * </ul>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Keith_number">Keith Number -
+ *      Wikipedia</a>
+ * @see <a href="https://mathworld.wolfram.com/KeithNumber.html">Keith Number -
+ *      MathWorld</a>
+ */
+public final class KeithNumber {
     private KeithNumber() {
     }
 
-    // user-defined function that checks if the given number is Keith or not
-    static boolean isKeith(int x) {
-        // List stores all the digits of the X
+    /**
+     * Checks if a given number is a Keith number.
+     *
+     * <p>
+     * The algorithm works as follows:
+     * <ol>
+     * <li>Extract all digits of the number and store them in a list</li>
+     * <li>Generate subsequent terms by summing the last n digits</li>
+     * <li>Continue until a term equals or exceeds the original number</li>
+     * <li>If a term equals the number, it is a Keith number</li>
+     * </ol>
+     *
+     * @param number the number to check (must be positive)
+     * @return {@code true} if the number is a Keith number, {@code false} otherwise
+     * @throws IllegalArgumentException if the number is not positive
+     */
+    public static boolean isKeith(int number) {
+        if (number <= 0) {
+            throw new IllegalArgumentException("Number must be positive");
+        }
+
+        // Extract digits and store them in the list
         ArrayList<Integer> terms = new ArrayList<>();
-        // n denotes the number of digits
-        int temp = x;
-        int n = 0;
-        // executes until the condition becomes false
+        int temp = number;
+        int digitCount = 0;
+
         while (temp > 0) {
-            // determines the last digit of the number and add it to the List
             terms.add(temp % 10);
-            // removes the last digit
             temp = temp / 10;
-            // increments the number of digits (n) by 1
-            n++;
+            digitCount++;
         }
-        // reverse the List
+
+        // Reverse the list to get digits in correct order
         Collections.reverse(terms);
+
+        // Generate subsequent terms in the sequence
         int nextTerm = 0;
-        int i = n;
-        // finds next term for the series
-        // loop executes until the condition returns true
-        while (nextTerm < x) {
+        int currentIndex = digitCount;
+
+        while (nextTerm < number) {
             nextTerm = 0;
-            // next term is the sum of previous n terms (it depends on number of digits the number
-            // has)
-            for (int j = 1; j <= n; j++) {
-                nextTerm = nextTerm + terms.get(i - j);
+            // Sum the last 'digitCount' terms
+            for (int j = 1; j <= digitCount; j++) {
+                nextTerm = nextTerm + terms.get(currentIndex - j);
             }
             terms.add(nextTerm);
-            i++;
+            currentIndex++;
         }
-        // when the control comes out of the while loop, there will be two conditions:
-        // either nextTerm will be equal to x or greater than x
-        // if equal, the given number is Keith, else not
-        return (nextTerm == x);
+
+        // Check if the generated term equals the original number
+        return (nextTerm == number);
     }
 
-    // driver code
+    /**
+     * Main method for demonstrating Keith number detection.
+     * Reads a number from standard input and checks if it is a Keith number.
+     *
+     * @param args command line arguments (not used)
+     */
     public static void main(String[] args) {
-        Scanner in = new Scanner(System.in);
-        int n = in.nextInt();
-        if (isKeith(n)) {
-            System.out.println("Yes, the given number is a Keith number.");
+        Scanner scanner = new Scanner(System.in);
+        System.out.print("Enter a positive integer: ");
+        int number = scanner.nextInt();
+
+        if (isKeith(number)) {
+            System.out.println("Yes, " + number + " is a Keith number.");
         } else {
-            System.out.println("No, the given number is not a Keith number.");
+            System.out.println("No, " + number + " is not a Keith number.");
         }
-        in.close();
+        scanner.close();
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/KeithNumberTest.java b/src/test/java/com/thealgorithms/maths/KeithNumberTest.java
new file mode 100644
index 000000000000..cac6b925e5c1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/KeithNumberTest.java
@@ -0,0 +1,153 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test cases for {@link KeithNumber}.
+ */
+class KeithNumberTest {
+
+    /**
+     * Tests single-digit Keith numbers.
+     * All single-digit numbers (1-9) are Keith numbers by definition.
+     */
+    @Test
+    void testSingleDigitKeithNumbers() {
+        assertTrue(KeithNumber.isKeith(1));
+        assertTrue(KeithNumber.isKeith(2));
+        assertTrue(KeithNumber.isKeith(3));
+        assertTrue(KeithNumber.isKeith(4));
+        assertTrue(KeithNumber.isKeith(5));
+        assertTrue(KeithNumber.isKeith(6));
+        assertTrue(KeithNumber.isKeith(7));
+        assertTrue(KeithNumber.isKeith(8));
+        assertTrue(KeithNumber.isKeith(9));
+    }
+
+    /**
+     * Tests two-digit Keith numbers.
+     * Known two-digit Keith numbers: 14, 19, 28, 47, 61, 75.
+     */
+    @Test
+    void testTwoDigitKeithNumbers() {
+        assertTrue(KeithNumber.isKeith(14));
+        assertTrue(KeithNumber.isKeith(19));
+        assertTrue(KeithNumber.isKeith(28));
+        assertTrue(KeithNumber.isKeith(47));
+        assertTrue(KeithNumber.isKeith(61));
+        assertTrue(KeithNumber.isKeith(75));
+    }
+
+    /**
+     * Tests three-digit Keith numbers.
+     * Known three-digit Keith numbers: 197, 742.
+     */
+    @Test
+    void testThreeDigitKeithNumbers() {
+        assertTrue(KeithNumber.isKeith(197));
+        assertTrue(KeithNumber.isKeith(742));
+    }
+
+    /**
+     * Tests four-digit Keith numbers.
+     * Known four-digit Keith numbers: 1104, 1537, 2208, 2580, 3684, 4788, 7385,
+     * 7647, 7909.
+     */
+    @Test
+    void testFourDigitKeithNumbers() {
+        assertTrue(KeithNumber.isKeith(1104));
+        assertTrue(KeithNumber.isKeith(1537));
+        assertTrue(KeithNumber.isKeith(2208));
+    }
+
+    /**
+     * Tests two-digit non-Keith numbers.
+     */
+    @Test
+    void testTwoDigitNonKeithNumbers() {
+        assertFalse(KeithNumber.isKeith(10));
+        assertFalse(KeithNumber.isKeith(11));
+        assertFalse(KeithNumber.isKeith(12));
+        assertFalse(KeithNumber.isKeith(13));
+        assertFalse(KeithNumber.isKeith(15));
+        assertFalse(KeithNumber.isKeith(20));
+        assertFalse(KeithNumber.isKeith(30));
+        assertFalse(KeithNumber.isKeith(50));
+    }
+
+    /**
+     * Tests three-digit non-Keith numbers.
+     */
+    @Test
+    void testThreeDigitNonKeithNumbers() {
+        assertFalse(KeithNumber.isKeith(100));
+        assertFalse(KeithNumber.isKeith(123));
+        assertFalse(KeithNumber.isKeith(196));
+        assertFalse(KeithNumber.isKeith(198));
+        assertFalse(KeithNumber.isKeith(456));
+        assertFalse(KeithNumber.isKeith(741));
+        assertFalse(KeithNumber.isKeith(743));
+        assertFalse(KeithNumber.isKeith(999));
+    }
+
+    /**
+     * Tests validation for edge case 14 in detail.
+     * 14 is a Keith number: 1, 4, 5 (1+4), 9 (4+5), 14 (5+9).
+     */
+    @Test
+    void testKeithNumber14() {
+        assertTrue(KeithNumber.isKeith(14));
+    }
+
+    /**
+     * Tests validation for edge case 197 in detail.
+     * 197 is a Keith number: 1, 9, 7, 17, 33, 57, 107, 197.
+     */
+    @Test
+    void testKeithNumber197() {
+        assertTrue(KeithNumber.isKeith(197));
+    }
+
+    /**
+     * Tests that zero throws an IllegalArgumentException.
+     */
+    @Test
+    void testZeroThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> KeithNumber.isKeith(0));
+    }
+
+    /**
+     * Tests that negative numbers throw an IllegalArgumentException.
+     */
+    @Test
+    void testNegativeNumbersThrowException() {
+        assertThrows(IllegalArgumentException.class, () -> KeithNumber.isKeith(-1));
+        assertThrows(IllegalArgumentException.class, () -> KeithNumber.isKeith(-14));
+        assertThrows(IllegalArgumentException.class, () -> KeithNumber.isKeith(-100));
+    }
+
+    /**
+     * Tests various edge cases with larger numbers.
+     */
+    @Test
+    void testLargerNumbers() {
+        assertTrue(KeithNumber.isKeith(2208));
+        assertFalse(KeithNumber.isKeith(2207));
+        assertFalse(KeithNumber.isKeith(2209));
+    }
+
+    /**
+     * Tests the expected behavior with all two-digit Keith numbers.
+     */
+    @Test
+    void testAllKnownTwoDigitKeithNumbers() {
+        int[] knownKeithNumbers = {14, 19, 28, 47, 61, 75};
+        for (int number : knownKeithNumbers) {
+            assertTrue(KeithNumber.isKeith(number), "Expected " + number + " to be a Keith number");
+        }
+    }
+}

From 883a050162dbc4907c030c43bd9f331b0bcc5245 Mon Sep 17 00:00:00 2001
From: Sameer Prajapati <sameerprajapati066@gmail.com>
Date: Mon, 13 Oct 2025 03:15:46 +0530
Subject: [PATCH 1013/1338] =?UTF-8?q?Added=20Dinic=E2=80=99s=20Max=20Flow?=
 =?UTF-8?q?=20algorithm=20with=20tests=20[Graphs]=20(#6762)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Add Dinics max flow algorithm with tests and index update

* Docs: add Dinic reference link and apply clang-format

* Fix: Checkstyle violations in Dinic and tests

* style: apply clang-format to Dinic and tests

---------

Co-authored-by: a <alexanderklmn@gmail.com>
---
 DIRECTORY.md                                  |   1 +
 .../java/com/thealgorithms/graph/Dinic.java   | 119 ++++++++++++++++++
 .../com/thealgorithms/graph/DinicTest.java    |  71 +++++++++++
 3 files changed, 191 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/Dinic.java
 create mode 100644 src/test/java/com/thealgorithms/graph/DinicTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index ff56d16db947..8fbcbaaec96e 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -353,6 +353,7 @@
           - 📄 [PredecessorConstrainedDfs](src/main/java/com/thealgorithms/graph/PredecessorConstrainedDfs.java)
           - 📄 [StronglyConnectedComponentOptimized](src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
           - 📄 [TravelingSalesman](src/main/java/com/thealgorithms/graph/TravelingSalesman.java)
+          - 📄 [Dinic](src/main/java/com/thealgorithms/graph/Dinic.java)
         - 📁 **greedyalgorithms**
           - 📄 [ActivitySelection](src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
           - 📄 [BandwidthAllocation](src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java)
diff --git a/src/main/java/com/thealgorithms/graph/Dinic.java b/src/main/java/com/thealgorithms/graph/Dinic.java
new file mode 100644
index 000000000000..c45bd62ddfbb
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/Dinic.java
@@ -0,0 +1,119 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.Queue;
+
+/**
+ * Dinic's algorithm for computing maximum flow in a directed graph.
+ *
+ * <p>Time complexity: O(E * V^2) in the worst case, but typically faster in practice
+ * and near O(E * sqrt(V)) for unit networks.</p>
+ *
+ * <p>The graph is represented using a capacity matrix where capacity[u][v] is the
+ * capacity of the directed edge u -> v. Capacities must be non-negative.
+ * The algorithm builds level graphs using BFS and finds blocking flows using DFS
+ * with current-edge optimization.</p>
+ *
+ * <p>This implementation mirrors the API and validation style of
+ * {@link EdmondsKarp#maxFlow(int[][], int, int)} for consistency.</p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Dinic%27s_algorithm">Wikipedia: Dinic's algorithm</a>
+ */
+public final class Dinic {
+    private Dinic() {
+    }
+
+    /**
+     * Computes the maximum flow from source to sink using Dinic's algorithm.
+     *
+     * @param capacity square capacity matrix (n x n); entries must be >= 0
+     * @param source source vertex index in [0, n)
+     * @param sink sink vertex index in [0, n)
+     * @return the maximum flow value
+     * @throws IllegalArgumentException if the input matrix is null/non-square/has negatives or
+     *     indices invalid
+     */
+    public static int maxFlow(int[][] capacity, int source, int sink) {
+        if (capacity == null || capacity.length == 0) {
+            throw new IllegalArgumentException("Capacity matrix must not be null or empty");
+        }
+        final int n = capacity.length;
+        for (int i = 0; i < n; i++) {
+            if (capacity[i] == null || capacity[i].length != n) {
+                throw new IllegalArgumentException("Capacity matrix must be square");
+            }
+            for (int j = 0; j < n; j++) {
+                if (capacity[i][j] < 0) {
+                    throw new IllegalArgumentException("Capacities must be non-negative");
+                }
+            }
+        }
+        if (source < 0 || sink < 0 || source >= n || sink >= n) {
+            throw new IllegalArgumentException("Source and sink must be valid vertex indices");
+        }
+        if (source == sink) {
+            return 0;
+        }
+
+        // residual capacities
+        int[][] residual = new int[n][n];
+        for (int i = 0; i < n; i++) {
+            residual[i] = Arrays.copyOf(capacity[i], n);
+        }
+
+        int[] level = new int[n];
+        int flow = 0;
+        while (bfsBuildLevelGraph(residual, source, sink, level)) {
+            int[] next = new int[n]; // current-edge optimization
+            int pushed;
+            do {
+                pushed = dfsBlocking(residual, level, next, source, sink, Integer.MAX_VALUE);
+                flow += pushed;
+            } while (pushed > 0);
+        }
+        return flow;
+    }
+
+    private static boolean bfsBuildLevelGraph(int[][] residual, int source, int sink, int[] level) {
+        Arrays.fill(level, -1);
+        level[source] = 0;
+        Queue<Integer> q = new ArrayDeque<>();
+        q.add(source);
+        while (!q.isEmpty()) {
+            int u = q.poll();
+            for (int v = 0; v < residual.length; v++) {
+                if (residual[u][v] > 0 && level[v] == -1) {
+                    level[v] = level[u] + 1;
+                    if (v == sink) {
+                        return true;
+                    }
+                    q.add(v);
+                }
+            }
+        }
+        return level[sink] != -1;
+    }
+
+    private static int dfsBlocking(int[][] residual, int[] level, int[] next, int u, int sink, int f) {
+        if (u == sink) {
+            return f;
+        }
+        final int n = residual.length;
+        for (int v = next[u]; v < n; v++, next[u] = v) {
+            if (residual[u][v] <= 0) {
+                continue;
+            }
+            if (level[v] != level[u] + 1) {
+                continue;
+            }
+            int pushed = dfsBlocking(residual, level, next, v, sink, Math.min(f, residual[u][v]));
+            if (pushed > 0) {
+                residual[u][v] -= pushed;
+                residual[v][u] += pushed;
+                return pushed;
+            }
+        }
+        return 0;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/DinicTest.java b/src/test/java/com/thealgorithms/graph/DinicTest.java
new file mode 100644
index 000000000000..912f787519fa
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/DinicTest.java
@@ -0,0 +1,71 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class DinicTest {
+    @Test
+    @DisplayName("Classic CLRS network yields max flow 23 (Dinic)")
+    void clrsExample() {
+        int[][] capacity = {{0, 16, 13, 0, 0, 0}, {0, 0, 10, 12, 0, 0}, {0, 4, 0, 0, 14, 0}, {0, 0, 9, 0, 0, 20}, {0, 0, 0, 7, 0, 4}, {0, 0, 0, 0, 0, 0}};
+        int maxFlow = Dinic.maxFlow(capacity, 0, 5);
+        assertEquals(23, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Disconnected network has zero flow (Dinic)")
+    void disconnectedGraph() {
+        int[][] capacity = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};
+        int maxFlow = Dinic.maxFlow(capacity, 0, 2);
+        assertEquals(0, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Source equals sink returns zero (Dinic)")
+    void sourceEqualsSink() {
+        int[][] capacity = {{0, 5}, {0, 0}};
+        int maxFlow = Dinic.maxFlow(capacity, 0, 0);
+        assertEquals(0, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Invalid matrix throws exception (Dinic)")
+    void invalidMatrix() {
+        int[][] capacity = {{0, 1}, {1}};
+        assertThrows(IllegalArgumentException.class, () -> Dinic.maxFlow(capacity, 0, 1));
+    }
+
+    @Test
+    @DisplayName("Dinic matches Edmonds-Karp on random small graphs")
+    void parityWithEdmondsKarp() {
+        java.util.Random rnd = new java.util.Random(42);
+        for (int n = 3; n <= 7; n++) {
+            for (int it = 0; it < 25; it++) {
+                int[][] cap = new int[n][n];
+                for (int i = 0; i < n; i++) {
+                    for (int j = 0; j < n; j++) {
+                        if (i != j && rnd.nextDouble() < 0.35) {
+                            cap[i][j] = rnd.nextInt(10); // capacities 0..9
+                        }
+                    }
+                }
+                int s = 0;
+                int t = n - 1;
+                int f1 = Dinic.maxFlow(copyMatrix(cap), s, t);
+                int f2 = EdmondsKarp.maxFlow(cap, s, t);
+                assertEquals(f2, f1);
+            }
+        }
+    }
+
+    private static int[][] copyMatrix(int[][] a) {
+        int[][] b = new int[a.length][a.length];
+        for (int i = 0; i < a.length; i++) {
+            b[i] = java.util.Arrays.copyOf(a[i], a[i].length);
+        }
+        return b;
+    }
+}

From f30d10117dd4317f9b055e0e1abb6f89f61e43c2 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Mon, 13 Oct 2025 13:12:10 +0530
Subject: [PATCH 1014/1338] refactor: Enhance docs, code, add tests in
 `LeonardoNumber` (#6743)

---
 .../thealgorithms/maths/LeonardoNumber.java   |  66 ++++++-
 .../maths/LeonardoNumberTest.java             | 170 ++++++++++++++++--
 2 files changed, 216 insertions(+), 20 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/LeonardoNumber.java b/src/main/java/com/thealgorithms/maths/LeonardoNumber.java
index bbeec052777f..9ac3691a6285 100644
--- a/src/main/java/com/thealgorithms/maths/LeonardoNumber.java
+++ b/src/main/java/com/thealgorithms/maths/LeonardoNumber.java
@@ -1,25 +1,79 @@
 package com.thealgorithms.maths;
 
 /**
- * https://en.wikipedia.org/wiki/Leonardo_number
+ * Utility class for calculating Leonardo Numbers.
+ * <p>
+ * Leonardo numbers are a sequence of numbers defined by the recurrence:
+ * L(n) = L(n-1) + L(n-2) + 1, with L(0) = 1 and L(1) = 1
+ * <p>
+ * The sequence begins: 1, 1, 3, 5, 9, 15, 25, 41, 67, 109, 177, ...
+ * <p>
+ * This class provides both a recursive implementation and an optimized
+ * iterative
+ * implementation for calculating Leonardo numbers.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Leonardo_number">Leonardo Number
+ *      - Wikipedia</a>
+ * @see <a href="https://oeis.org/A001595">OEIS A001595</a>
  */
 public final class LeonardoNumber {
     private LeonardoNumber() {
     }
 
     /**
-     * Calculate nth Leonardo Number (1, 1, 3, 5, 9, 15, 25, 41, 67, 109, 177, ...)
+     * Calculates the nth Leonardo Number using recursion.
+     * <p>
+     * Time Complexity: O(2^n) - exponential due to repeated calculations
+     * Space Complexity: O(n) - due to recursion stack
+     * <p>
+     * Note: This method is not recommended for large values of n due to exponential
+     * time complexity.
+     * Consider using {@link #leonardoNumberIterative(int)} for better performance.
      *
-     * @param n the index of Leonardo Number to calculate
-     * @return nth number of Leonardo sequences
+     * @param n the index of the Leonardo Number to calculate (must be non-negative)
+     * @return the nth Leonardo Number
+     * @throws IllegalArgumentException if n is negative
      */
     public static int leonardoNumber(int n) {
         if (n < 0) {
-            throw new ArithmeticException();
+            throw new IllegalArgumentException("Input must be non-negative. Received: " + n);
         }
         if (n == 0 || n == 1) {
             return 1;
         }
-        return (leonardoNumber(n - 1) + leonardoNumber(n - 2) + 1);
+        return leonardoNumber(n - 1) + leonardoNumber(n - 2) + 1;
+    }
+
+    /**
+     * Calculates the nth Leonardo Number using an iterative approach.
+     * <p>
+     * This method provides better performance than the recursive version for large
+     * values of n.
+     * <p>
+     * Time Complexity: O(n)
+     * Space Complexity: O(1)
+     *
+     * @param n the index of the Leonardo Number to calculate (must be non-negative)
+     * @return the nth Leonardo Number
+     * @throws IllegalArgumentException if n is negative
+     */
+    public static int leonardoNumberIterative(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input must be non-negative. Received: " + n);
+        }
+        if (n == 0 || n == 1) {
+            return 1;
+        }
+
+        int previous = 1;
+        int current = 1;
+
+        for (int i = 2; i <= n; i++) {
+            int next = current + previous + 1;
+            previous = current;
+            current = next;
+        }
+
+        return current;
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java b/src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java
index 705f1a1006fa..baf4540cf239 100644
--- a/src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java
@@ -1,29 +1,171 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
-public class LeonardoNumberTest {
+/**
+ * Test cases for {@link LeonardoNumber} class.
+ * <p>
+ * Tests both recursive and iterative implementations with various input values
+ * including edge cases and boundary conditions.
+ */
+class LeonardoNumberTest {
+
+    // Tests for recursive implementation
+
+    @Test
+    void testLeonardoNumberNegative() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> LeonardoNumber.leonardoNumber(-1));
+    }
+
+    @Test
+    void testLeonardoNumberNegativeLarge() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> LeonardoNumber.leonardoNumber(-100));
+    }
+
+    @Test
+    void testLeonardoNumberZero() {
+        Assertions.assertEquals(1, LeonardoNumber.leonardoNumber(0));
+    }
+
+    @Test
+    void testLeonardoNumberOne() {
+        Assertions.assertEquals(1, LeonardoNumber.leonardoNumber(1));
+    }
+
+    @Test
+    void testLeonardoNumberTwo() {
+        Assertions.assertEquals(3, LeonardoNumber.leonardoNumber(2));
+    }
+
+    @Test
+    void testLeonardoNumberThree() {
+        Assertions.assertEquals(5, LeonardoNumber.leonardoNumber(3));
+    }
+
+    @Test
+    void testLeonardoNumberFour() {
+        Assertions.assertEquals(9, LeonardoNumber.leonardoNumber(4));
+    }
+
+    @Test
+    void testLeonardoNumberFive() {
+        Assertions.assertEquals(15, LeonardoNumber.leonardoNumber(5));
+    }
+
+    @Test
+    void testLeonardoNumberSix() {
+        Assertions.assertEquals(25, LeonardoNumber.leonardoNumber(6));
+    }
+
+    @Test
+    void testLeonardoNumberSeven() {
+        Assertions.assertEquals(41, LeonardoNumber.leonardoNumber(7));
+    }
+
+    @Test
+    void testLeonardoNumberEight() {
+        Assertions.assertEquals(67, LeonardoNumber.leonardoNumber(8));
+    }
+
+    @Test
+    void testLeonardoNumberTen() {
+        Assertions.assertEquals(177, LeonardoNumber.leonardoNumber(10));
+    }
+
+    @Test
+    void testLeonardoNumberFifteen() {
+        Assertions.assertEquals(1973, LeonardoNumber.leonardoNumber(15));
+    }
+
     @Test
-    void leonardoNumberNegative() {
-        assertThrows(ArithmeticException.class, () -> LeonardoNumber.leonardoNumber(-1));
+    void testLeonardoNumberTwenty() {
+        Assertions.assertEquals(21891, LeonardoNumber.leonardoNumber(20));
     }
+
+    // Tests for iterative implementation
+
+    @Test
+    void testLeonardoNumberIterativeNegative() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> LeonardoNumber.leonardoNumberIterative(-1));
+    }
+
+    @Test
+    void testLeonardoNumberIterativeNegativeLarge() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> LeonardoNumber.leonardoNumberIterative(-50));
+    }
+
+    @Test
+    void testLeonardoNumberIterativeZero() {
+        Assertions.assertEquals(1, LeonardoNumber.leonardoNumberIterative(0));
+    }
+
+    @Test
+    void testLeonardoNumberIterativeOne() {
+        Assertions.assertEquals(1, LeonardoNumber.leonardoNumberIterative(1));
+    }
+
+    @Test
+    void testLeonardoNumberIterativeTwo() {
+        Assertions.assertEquals(3, LeonardoNumber.leonardoNumberIterative(2));
+    }
+
+    @Test
+    void testLeonardoNumberIterativeThree() {
+        Assertions.assertEquals(5, LeonardoNumber.leonardoNumberIterative(3));
+    }
+
+    @Test
+    void testLeonardoNumberIterativeFour() {
+        Assertions.assertEquals(9, LeonardoNumber.leonardoNumberIterative(4));
+    }
+
     @Test
-    void leonardoNumberZero() {
-        assertEquals(1, LeonardoNumber.leonardoNumber(0));
+    void testLeonardoNumberIterativeFive() {
+        Assertions.assertEquals(15, LeonardoNumber.leonardoNumberIterative(5));
     }
+
     @Test
-    void leonardoNumberOne() {
-        assertEquals(1, LeonardoNumber.leonardoNumber(1));
+    void testLeonardoNumberIterativeSix() {
+        Assertions.assertEquals(25, LeonardoNumber.leonardoNumberIterative(6));
     }
+
     @Test
-    void leonardoNumberFive() {
-        assertEquals(15, LeonardoNumber.leonardoNumber(5));
+    void testLeonardoNumberIterativeSeven() {
+        Assertions.assertEquals(41, LeonardoNumber.leonardoNumberIterative(7));
     }
+
+    @Test
+    void testLeonardoNumberIterativeEight() {
+        Assertions.assertEquals(67, LeonardoNumber.leonardoNumberIterative(8));
+    }
+
+    @Test
+    void testLeonardoNumberIterativeTen() {
+        Assertions.assertEquals(177, LeonardoNumber.leonardoNumberIterative(10));
+    }
+
+    @Test
+    void testLeonardoNumberIterativeFifteen() {
+        Assertions.assertEquals(1973, LeonardoNumber.leonardoNumberIterative(15));
+    }
+
+    @Test
+    void testLeonardoNumberIterativeTwenty() {
+        Assertions.assertEquals(21891, LeonardoNumber.leonardoNumberIterative(20));
+    }
+
+    @Test
+    void testLeonardoNumberIterativeTwentyFive() {
+        Assertions.assertEquals(242785, LeonardoNumber.leonardoNumberIterative(25));
+    }
+
+    // Consistency tests between recursive and iterative implementations
+
     @Test
-    void leonardoNumberTwenty() {
-        assertEquals(21891, LeonardoNumber.leonardoNumber(20));
+    void testConsistencyBetweenImplementations() {
+        for (int i = 0; i <= 15; i++) {
+            Assertions.assertEquals(LeonardoNumber.leonardoNumber(i), LeonardoNumber.leonardoNumberIterative(i), "Mismatch at index " + i);
+        }
     }
 }

From 8b8434cb51bc6a81317760ff18b28c42797fee85 Mon Sep 17 00:00:00 2001
From: Microindole <1513979779@qq.com>
Date: Mon, 13 Oct 2025 20:47:50 +0800
Subject: [PATCH 1015/1338] feat(graph): Add Edmonds's algorithm for minimum
 spanning arborescence (#6771)

* feat(graph): Add Edmonds's algorithm for minimum spanning arborescence

* test: Add test cases to achieve 100% coverage
---
 .../java/com/thealgorithms/graph/Edmonds.java | 201 ++++++++++++++++++
 .../com/thealgorithms/graph/EdmondsTest.java  | 172 +++++++++++++++
 2 files changed, 373 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/Edmonds.java
 create mode 100644 src/test/java/com/thealgorithms/graph/EdmondsTest.java

diff --git a/src/main/java/com/thealgorithms/graph/Edmonds.java b/src/main/java/com/thealgorithms/graph/Edmonds.java
new file mode 100644
index 000000000000..4ddb8f9ff544
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/Edmonds.java
@@ -0,0 +1,201 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * An implementation of Edmonds's algorithm (also known as the Chu–Liu/Edmonds algorithm)
+ * for finding a Minimum Spanning Arborescence (MSA).
+ *
+ * <p>An MSA is a directed graph equivalent of a Minimum Spanning Tree. It is a tree rooted
+ * at a specific vertex 'r' that reaches all other vertices, such that the sum of the
+ * weights of its edges is minimized.
+ *
+ * <p>The algorithm works recursively:
+ * <ol>
+ * <li>For each vertex other than the root, select the incoming edge with the minimum weight.</li>
+ * <li>If the selected edges form a spanning arborescence, it is the MSA.</li>
+ * <li>If cycles are formed, contract each cycle into a new "supernode".</li>
+ * <li>Modify the weights of edges entering the new supernode.</li>
+ * <li>Recursively call the algorithm on the contracted graph.</li>
+ * <li>The final cost is the sum of the initial edge selections and the result of the recursive call.</li>
+ * </ol>
+ *
+ * <p>Time Complexity: O(E * V) where E is the number of edges and V is the number of vertices.
+ *
+ * <p>References:
+ * <ul>
+ * <li><a href="https://en.wikipedia.org/wiki/Edmonds%27_algorithm">Wikipedia: Edmonds's algorithm</a></li>
+ * </ul>
+ */
+public final class Edmonds {
+
+    private Edmonds() {
+    }
+
+    /**
+     * Represents a directed weighted edge in the graph.
+     */
+    public static class Edge {
+        final int from;
+        final int to;
+        final long weight;
+
+        /**
+         * Constructs a directed edge.
+         *
+         * @param from source vertex
+         * @param to destination vertex
+         * @param weight edge weight
+         */
+        public Edge(int from, int to, long weight) {
+            this.from = from;
+            this.to = to;
+            this.weight = weight;
+        }
+    }
+
+    /**
+     * Computes the total weight of the Minimum Spanning Arborescence of a directed,
+     * weighted graph from a given root.
+     *
+     * @param numVertices the number of vertices, labeled {@code 0..numVertices-1}
+     * @param edges list of directed edges in the graph
+     * @param root the root vertex
+     * @return the total weight of the MSA. Returns -1 if not all vertices are reachable
+     *         from the root or if a valid arborescence cannot be formed.
+     * @throws IllegalArgumentException if {@code numVertices <= 0} or {@code root} is out of range.
+     */
+    public static long findMinimumSpanningArborescence(int numVertices, List<Edge> edges, int root) {
+        if (root < 0 || root >= numVertices) {
+            throw new IllegalArgumentException("Invalid number of vertices or root");
+        }
+        if (numVertices == 1) {
+            return 0;
+        }
+
+        return findMSARecursive(numVertices, edges, root);
+    }
+
+    /**
+     * Recursive helper method for finding MSA.
+     */
+    private static long findMSARecursive(int n, List<Edge> edges, int root) {
+        long[] minWeightEdge = new long[n];
+        int[] predecessor = new int[n];
+        Arrays.fill(minWeightEdge, Long.MAX_VALUE);
+        Arrays.fill(predecessor, -1);
+
+        for (Edge edge : edges) {
+            if (edge.to != root && edge.weight < minWeightEdge[edge.to]) {
+                minWeightEdge[edge.to] = edge.weight;
+                predecessor[edge.to] = edge.from;
+            }
+        }
+        // Check if all non-root nodes are reachable
+        for (int i = 0; i < n; i++) {
+            if (i != root && minWeightEdge[i] == Long.MAX_VALUE) {
+                return -1; // No spanning arborescence exists
+            }
+        }
+        int[] cycleId = new int[n];
+        Arrays.fill(cycleId, -1);
+        boolean[] visited = new boolean[n];
+        int cycleCount = 0;
+
+        for (int i = 0; i < n; i++) {
+            if (visited[i]) {
+                continue;
+            }
+
+            List<Integer> path = new ArrayList<>();
+            int curr = i;
+
+            // Follow predecessor chain
+            while (curr != -1 && !visited[curr]) {
+                visited[curr] = true;
+                path.add(curr);
+                curr = predecessor[curr];
+            }
+
+            // If we hit a visited node, check if it forms a cycle
+            if (curr != -1) {
+                boolean inCycle = false;
+                for (int node : path) {
+                    if (node == curr) {
+                        inCycle = true;
+                    }
+                    if (inCycle) {
+                        cycleId[node] = cycleCount;
+                    }
+                }
+                if (inCycle) {
+                    cycleCount++;
+                }
+            }
+        }
+        if (cycleCount == 0) {
+            long totalWeight = 0;
+            for (int i = 0; i < n; i++) {
+                if (i != root) {
+                    totalWeight += minWeightEdge[i];
+                }
+            }
+            return totalWeight;
+        }
+        long cycleWeightSum = 0;
+        for (int i = 0; i < n; i++) {
+            if (cycleId[i] >= 0) {
+                cycleWeightSum += minWeightEdge[i];
+            }
+        }
+
+        // Map old nodes to new nodes (cycles become supernodes)
+        int[] newNodeMap = new int[n];
+        int[] cycleToNewNode = new int[cycleCount];
+        int newN = 0;
+
+        // Assign new node IDs to cycles first
+        for (int i = 0; i < cycleCount; i++) {
+            cycleToNewNode[i] = newN++;
+        }
+
+        // Assign new node IDs to non-cycle nodes
+        for (int i = 0; i < n; i++) {
+            if (cycleId[i] == -1) {
+                newNodeMap[i] = newN++;
+            } else {
+                newNodeMap[i] = cycleToNewNode[cycleId[i]];
+            }
+        }
+
+        int newRoot = newNodeMap[root];
+
+        // Build contracted graph
+        List<Edge> newEdges = new ArrayList<>();
+        for (Edge edge : edges) {
+            int uCycleId = cycleId[edge.from];
+            int vCycleId = cycleId[edge.to];
+
+            // Skip edges internal to a cycle
+            if (uCycleId >= 0 && uCycleId == vCycleId) {
+                continue;
+            }
+
+            int newU = newNodeMap[edge.from];
+            int newV = newNodeMap[edge.to];
+
+            long newWeight = edge.weight;
+            // Adjust weight for edges entering a cycle
+            if (vCycleId >= 0) {
+                newWeight -= minWeightEdge[edge.to];
+            }
+
+            if (newU != newV) {
+                newEdges.add(new Edge(newU, newV, newWeight));
+            }
+        }
+        return cycleWeightSum + findMSARecursive(newN, newEdges, newRoot);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/EdmondsTest.java b/src/test/java/com/thealgorithms/graph/EdmondsTest.java
new file mode 100644
index 000000000000..ab5740c94217
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/EdmondsTest.java
@@ -0,0 +1,172 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class EdmondsTest {
+
+    @Test
+    void testSimpleGraphNoCycle() {
+        int n = 4;
+        int root = 0;
+        List<Edmonds.Edge> edges = new ArrayList<>();
+        edges.add(new Edmonds.Edge(0, 1, 10));
+        edges.add(new Edmonds.Edge(0, 2, 1));
+        edges.add(new Edmonds.Edge(2, 1, 2));
+        edges.add(new Edmonds.Edge(2, 3, 5));
+
+        // Expected arborescence edges: (0,2), (2,1), (2,3)
+        // Weights: 1 + 2 + 5 = 8
+        long result = Edmonds.findMinimumSpanningArborescence(n, edges, root);
+        assertEquals(8, result);
+    }
+
+    @Test
+    void testGraphWithOneCycle() {
+        int n = 4;
+        int root = 0;
+        List<Edmonds.Edge> edges = new ArrayList<>();
+        edges.add(new Edmonds.Edge(0, 1, 10));
+        edges.add(new Edmonds.Edge(2, 1, 4));
+        edges.add(new Edmonds.Edge(1, 2, 5));
+        edges.add(new Edmonds.Edge(2, 3, 6));
+
+        // Min edges: (2,1, w=4), (1,2, w=5), (2,3, w=6)
+        // Cycle: 1 -> 2 -> 1, cost = 4 + 5 = 9
+        // Contract {1,2} to C.
+        // New edge (0,C) with w = 10 - min_in(1) = 10 - 4 = 6
+        // New edge (C,3) with w = 6
+        // Contracted MSA cost = 6 + 6 = 12
+        // Total cost = cycle_cost + contracted_msa_cost = 9 + 12 = 21
+        long result = Edmonds.findMinimumSpanningArborescence(n, edges, root);
+        assertEquals(21, result);
+    }
+
+    @Test
+    void testComplexGraphWithCycle() {
+        int n = 6;
+        int root = 0;
+        List<Edmonds.Edge> edges = new ArrayList<>();
+        edges.add(new Edmonds.Edge(0, 1, 10));
+        edges.add(new Edmonds.Edge(0, 2, 20));
+        edges.add(new Edmonds.Edge(1, 2, 5));
+        edges.add(new Edmonds.Edge(2, 3, 10));
+        edges.add(new Edmonds.Edge(3, 1, 3));
+        edges.add(new Edmonds.Edge(1, 4, 7));
+        edges.add(new Edmonds.Edge(3, 4, 2));
+        edges.add(new Edmonds.Edge(4, 5, 5));
+
+        // Min edges: (3,1,3), (1,2,5), (2,3,10), (3,4,2), (4,5,5)
+        // Cycle: 1->2->3->1, cost = 5+10+3=18
+        // Contract {1,2,3} to C.
+        // Edge (0,1,10) -> (0,C), w = 10-3=7
+        // Edge (0,2,20) -> (0,C), w = 20-5=15. Min is 7.
+        // Edge (1,4,7) -> (C,4,7)
+        // Edge (3,4,2) -> (C,4,2). Min is 2.
+        // Edge (4,5,5) -> (4,5,5)
+        // Contracted MSA: (0,C,7), (C,4,2), (4,5,5). Cost = 7+2+5=14
+        // Total cost = 18 + 14 = 32
+        long result = Edmonds.findMinimumSpanningArborescence(n, edges, root);
+        assertEquals(32, result);
+    }
+
+    @Test
+    void testUnreachableNode() {
+        int n = 4;
+        int root = 0;
+        List<Edmonds.Edge> edges = new ArrayList<>();
+        edges.add(new Edmonds.Edge(0, 1, 10));
+        edges.add(new Edmonds.Edge(2, 3, 5)); // Node 2 and 3 are unreachable from root 0
+
+        long result = Edmonds.findMinimumSpanningArborescence(n, edges, root);
+        assertEquals(-1, result);
+    }
+
+    @Test
+    void testNoEdgesToNonRootNodes() {
+        int n = 3;
+        int root = 0;
+        List<Edmonds.Edge> edges = new ArrayList<>();
+        edges.add(new Edmonds.Edge(0, 1, 10)); // Node 2 is unreachable
+
+        long result = Edmonds.findMinimumSpanningArborescence(n, edges, root);
+        assertEquals(-1, result);
+    }
+
+    @Test
+    void testSingleNode() {
+        int n = 1;
+        int root = 0;
+        List<Edmonds.Edge> edges = new ArrayList<>();
+
+        long result = Edmonds.findMinimumSpanningArborescence(n, edges, root);
+        assertEquals(0, result);
+    }
+
+    @Test
+    void testInvalidInputThrowsException() {
+        List<Edmonds.Edge> edges = new ArrayList<>();
+
+        assertThrows(IllegalArgumentException.class, () -> Edmonds.findMinimumSpanningArborescence(0, edges, 0));
+        assertThrows(IllegalArgumentException.class, () -> Edmonds.findMinimumSpanningArborescence(5, edges, -1));
+        assertThrows(IllegalArgumentException.class, () -> Edmonds.findMinimumSpanningArborescence(5, edges, 5));
+    }
+
+    @Test
+    void testCoverageForEdgeSelectionLogic() {
+        int n = 3;
+        int root = 0;
+        List<Edmonds.Edge> edges = new ArrayList<>();
+
+        // This will cover the `edge.weight < minWeightEdge[edge.to]` being false.
+        edges.add(new Edmonds.Edge(0, 1, 10));
+        edges.add(new Edmonds.Edge(2, 1, 20));
+
+        // This will cover the `edge.to != root` being false.
+        edges.add(new Edmonds.Edge(1, 0, 100));
+
+        // A regular edge to make the graph complete
+        edges.add(new Edmonds.Edge(0, 2, 5));
+
+        // Expected MSA: (0,1, w=10) and (0,2, w=5). Total weight = 15.
+        long result = Edmonds.findMinimumSpanningArborescence(n, edges, root);
+        assertEquals(15, result);
+    }
+
+    @Test
+    void testCoverageForContractedSelfLoop() {
+        int n = 4;
+        int root = 0;
+        List<Edmonds.Edge> edges = new ArrayList<>();
+
+        // Connect root to the cycle components
+        edges.add(new Edmonds.Edge(0, 1, 20));
+
+        // Create a cycle 1 -> 2 -> 1
+        edges.add(new Edmonds.Edge(1, 2, 5));
+        edges.add(new Edmonds.Edge(2, 1, 5));
+
+        // This is the CRITICAL edge for coverage:
+        // It connects two nodes (1 and 2) that are part of the SAME cycle.
+        // After contracting cycle {1, 2} into a supernode C, this edge becomes (C, C),
+        // which means newU == newV. This will trigger the `false` branch of the `if`.
+        edges.add(new Edmonds.Edge(1, 1, 100)); // Also a self-loop on a cycle node.
+
+        // Add another edge to ensure node 3 is reachable
+        edges.add(new Edmonds.Edge(1, 3, 10));
+
+        // Cycle {1,2} has cost 5+5=10.
+        // Contract {1,2} to supernode C.
+        // Edge (0,1,20) becomes (0,C, w=20-5=15).
+        // Edge (1,3,10) becomes (C,3, w=10).
+        // Edge (1,1,100) is discarded because newU == newV.
+        // Cost of contracted graph = 15 + 10 = 25.
+        // Total cost = cycle cost + contracted cost = 10 + 25 = 35.
+        long result = Edmonds.findMinimumSpanningArborescence(n, edges, root);
+        assertEquals(35, result);
+    }
+}

From 8726d401b7951d13eee7b081ecd49999babcb362 Mon Sep 17 00:00:00 2001
From: Sameer Prajapati <sameerprajapati066@gmail.com>
Date: Mon, 13 Oct 2025 23:52:55 +0530
Subject: [PATCH 1016/1338] =?UTF-8?q?Add=20Yen=E2=80=99s=20K-shortest=20lo?=
 =?UTF-8?q?opless=20paths=20with=20tests=20[GRAPHS]=20(#6773)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Add Yen’s K-shortest loopless paths with tests and index update

* style: fix Checkstyle in Yens algorithm and tests

* fix: resolve SpotBugs in Yens algorithm

* fix (PMD): rename short variables in the code

* (pmd): code fixes

* fix(bloomfilter): hash arrays by content to satisfy array membership tests

* style(pmd): fix EmptyControlStatement in validate() by returning early when src==dst

* style(pmd): remove unnecessary return in validate()
---
 DIRECTORY.md                                  |   1 +
 .../bloomfilter/BloomFilter.java              |  29 +-
 .../graph/YensKShortestPaths.java             | 263 ++++++++++++++++++
 .../graph/YensKShortestPathsTest.java         |  76 +++++
 4 files changed, 368 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/com/thealgorithms/graph/YensKShortestPaths.java
 create mode 100644 src/test/java/com/thealgorithms/graph/YensKShortestPathsTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 8fbcbaaec96e..3bfedac64b89 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -354,6 +354,7 @@
           - 📄 [StronglyConnectedComponentOptimized](src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
           - 📄 [TravelingSalesman](src/main/java/com/thealgorithms/graph/TravelingSalesman.java)
           - 📄 [Dinic](src/main/java/com/thealgorithms/graph/Dinic.java)
+          - 📄 [YensKShortestPaths](src/main/java/com/thealgorithms/graph/YensKShortestPaths.java)
         - 📁 **greedyalgorithms**
           - 📄 [ActivitySelection](src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
           - 📄 [BandwidthAllocation](src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
index d60b95110fc2..c84f25bd78e6 100644
--- a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
+++ b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
@@ -1,5 +1,6 @@
 package com.thealgorithms.datastructures.bloomfilter;
 
+import java.util.Arrays;
 import java.util.BitSet;
 
 /**
@@ -115,7 +116,7 @@ private static class Hash<T> {
          * @return the computed hash value
          */
         public int compute(T key) {
-            return index * asciiString(String.valueOf(key));
+            return index * contentHash(key);
         }
 
         /**
@@ -135,5 +136,31 @@ private int asciiString(String word) {
             }
             return sum;
         }
+
+        /**
+         * Computes a content-based hash for arrays; falls back to ASCII-sum of String value otherwise.
+         */
+        private int contentHash(Object key) {
+            if (key instanceof int[]) {
+                return Arrays.hashCode((int[]) key);
+            } else if (key instanceof long[]) {
+                return Arrays.hashCode((long[]) key);
+            } else if (key instanceof byte[]) {
+                return Arrays.hashCode((byte[]) key);
+            } else if (key instanceof short[]) {
+                return Arrays.hashCode((short[]) key);
+            } else if (key instanceof char[]) {
+                return Arrays.hashCode((char[]) key);
+            } else if (key instanceof boolean[]) {
+                return Arrays.hashCode((boolean[]) key);
+            } else if (key instanceof float[]) {
+                return Arrays.hashCode((float[]) key);
+            } else if (key instanceof double[]) {
+                return Arrays.hashCode((double[]) key);
+            } else if (key instanceof Object[]) {
+                return Arrays.deepHashCode((Object[]) key);
+            }
+            return asciiString(String.valueOf(key));
+        }
     }
 }
diff --git a/src/main/java/com/thealgorithms/graph/YensKShortestPaths.java b/src/main/java/com/thealgorithms/graph/YensKShortestPaths.java
new file mode 100644
index 000000000000..dfc8386de6ce
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/YensKShortestPaths.java
@@ -0,0 +1,263 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.PriorityQueue;
+import java.util.Set;
+
+/**
+ * Yen's algorithm for finding K loopless shortest paths in a directed graph with non-negative edge weights.
+ *
+ * <p>Input is an adjacency matrix of edge weights. A value of -1 indicates no edge.
+ * All existing edge weights must be non-negative. Zero-weight edges are allowed.</p>
+ *
+ * <p>References:
+ * - Wikipedia: Yen's algorithm (https://en.wikipedia.org/wiki/Yen%27s_algorithm)
+ * - Dijkstra's algorithm for the base shortest path computation.</p>
+ */
+public final class YensKShortestPaths {
+
+    private YensKShortestPaths() {
+    }
+
+    private static final int NO_EDGE = -1;
+    private static final long INF_COST = Long.MAX_VALUE / 4;
+
+    /**
+     * Compute up to k loopless shortest paths from src to dst using Yen's algorithm.
+     *
+     * @param weights adjacency matrix; weights[u][v] = -1 means no edge; otherwise non-negative edge weight
+     * @param src source vertex index
+     * @param dst destination vertex index
+     * @param k maximum number of paths to return (k >= 1)
+     * @return list of paths, each path is a list of vertex indices in order from src to dst
+     * @throws IllegalArgumentException on invalid inputs (null, non-square, negatives on existing edges, bad indices, k < 1)
+     */
+    public static List<List<Integer>> kShortestPaths(int[][] weights, int src, int dst, int k) {
+        validate(weights, src, dst, k);
+        final int n = weights.length;
+        // Make a defensive copy to avoid mutating caller's matrix
+        int[][] weightsCopy = new int[n][n];
+        for (int i = 0; i < n; i++) {
+            weightsCopy[i] = Arrays.copyOf(weights[i], n);
+        }
+
+        List<Path> shortestPaths = new ArrayList<>();
+        PriorityQueue<Path> candidates = new PriorityQueue<>(); // min-heap by cost then lexicographic nodes
+        Set<String> seen = new HashSet<>(); // deduplicate candidate paths by node sequence key
+
+        Path first = dijkstra(weightsCopy, src, dst, new boolean[n]);
+        if (first == null) {
+            return List.of();
+        }
+        shortestPaths.add(first);
+
+        for (int kIdx = 1; kIdx < k; kIdx++) {
+            Path lastPath = shortestPaths.get(kIdx - 1);
+            List<Integer> lastNodes = lastPath.nodes;
+            for (int i = 0; i < lastNodes.size() - 1; i++) {
+                int spurNode = lastNodes.get(i);
+                List<Integer> rootPath = lastNodes.subList(0, i + 1);
+
+                // Build modified graph: remove edges that would recreate same root + next edge as any A path
+                int[][] modifiedWeights = cloneMatrix(weightsCopy);
+
+                for (Path p : shortestPaths) {
+                    if (startsWith(p.nodes, rootPath) && p.nodes.size() > i + 1) {
+                        int u = p.nodes.get(i);
+                        int v = p.nodes.get(i + 1);
+                        modifiedWeights[u][v] = NO_EDGE; // remove edge
+                    }
+                }
+                // Prevent revisiting nodes in rootPath (loopless constraint), except spurNode itself
+                boolean[] blocked = new boolean[n];
+                for (int j = 0; j < rootPath.size() - 1; j++) {
+                    blocked[rootPath.get(j)] = true;
+                }
+
+                Path spurPath = dijkstra(modifiedWeights, spurNode, dst, blocked);
+                if (spurPath != null) {
+                    // concatenate rootPath (excluding spurNode at end) + spurPath
+                    List<Integer> totalNodes = new ArrayList<>(rootPath);
+                    // spurPath.nodes starts with spurNode; avoid duplication
+                    for (int idx = 1; idx < spurPath.nodes.size(); idx++) {
+                        totalNodes.add(spurPath.nodes.get(idx));
+                    }
+                    long rootCost = pathCost(weightsCopy, rootPath);
+                    long totalCost = rootCost + spurPath.cost; // spurPath.cost covers from spurNode to dst
+                    Path candidate = new Path(totalNodes, totalCost);
+                    String key = candidate.key();
+                    if (seen.add(key)) {
+                        candidates.add(candidate);
+                    }
+                }
+            }
+            if (candidates.isEmpty()) {
+                break;
+            }
+            shortestPaths.add(candidates.poll());
+        }
+
+        // Map to list of node indices for output
+        List<List<Integer>> result = new ArrayList<>(shortestPaths.size());
+        for (Path p : shortestPaths) {
+            result.add(new ArrayList<>(p.nodes));
+        }
+        return result;
+    }
+
+    private static void validate(int[][] weights, int src, int dst, int k) {
+        if (weights == null || weights.length == 0) {
+            throw new IllegalArgumentException("Weights matrix must not be null or empty");
+        }
+        int n = weights.length;
+        for (int i = 0; i < n; i++) {
+            if (weights[i] == null || weights[i].length != n) {
+                throw new IllegalArgumentException("Weights matrix must be square");
+            }
+            for (int j = 0; j < n; j++) {
+                int val = weights[i][j];
+                if (val < NO_EDGE) {
+                    throw new IllegalArgumentException("Weights must be -1 (no edge) or >= 0");
+                }
+            }
+        }
+        if (src < 0 || dst < 0 || src >= n || dst >= n) {
+            throw new IllegalArgumentException("Invalid src/dst indices");
+        }
+        if (k < 1) {
+            throw new IllegalArgumentException("k must be >= 1");
+        }
+    }
+
+    private static boolean startsWith(List<Integer> list, List<Integer> prefix) {
+        if (prefix.size() > list.size()) {
+            return false;
+        }
+        for (int i = 0; i < prefix.size(); i++) {
+            if (!Objects.equals(list.get(i), prefix.get(i))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private static int[][] cloneMatrix(int[][] a) {
+        int n = a.length;
+        int[][] b = new int[n][n];
+        for (int i = 0; i < n; i++) {
+            b[i] = Arrays.copyOf(a[i], n);
+        }
+        return b;
+    }
+
+    private static long pathCost(int[][] weights, List<Integer> nodes) {
+        long cost = 0;
+        for (int i = 0; i + 1 < nodes.size(); i++) {
+            int u = nodes.get(i);
+            int v = nodes.get(i + 1);
+            int edgeCost = weights[u][v];
+            if (edgeCost < 0) {
+                return INF_COST; // invalid
+            }
+            cost += edgeCost;
+        }
+        return cost;
+    }
+
+    private static Path dijkstra(int[][] weights, int src, int dst, boolean[] blocked) {
+        int n = weights.length;
+        final long inf = INF_COST;
+        long[] dist = new long[n];
+        int[] parent = new int[n];
+        Arrays.fill(dist, inf);
+        Arrays.fill(parent, -1);
+        PriorityQueue<Node> queue = new PriorityQueue<>();
+        if (blocked[src]) {
+            return null;
+        }
+        dist[src] = 0;
+        queue.add(new Node(src, 0));
+        while (!queue.isEmpty()) {
+            Node current = queue.poll();
+            if (current.dist != dist[current.u]) {
+                continue;
+            }
+            if (current.u == dst) {
+                break;
+            }
+            for (int v = 0; v < n; v++) {
+                int edgeWeight = weights[current.u][v];
+                if (edgeWeight >= 0 && !blocked[v]) {
+                    long newDist = current.dist + edgeWeight;
+                    if (newDist < dist[v]) {
+                        dist[v] = newDist;
+                        parent[v] = current.u;
+                        queue.add(new Node(v, newDist));
+                    }
+                }
+            }
+        }
+        if (dist[dst] >= inf) {
+            // If src==dst and not blocked, the path is trivial with cost 0
+            if (src == dst) {
+                List<Integer> nodes = new ArrayList<>();
+                nodes.add(src);
+                return new Path(nodes, 0);
+            }
+            return null;
+        }
+        // Reconstruct path
+        List<Integer> nodes = new ArrayList<>();
+        int cur = dst;
+        while (cur != -1) {
+            nodes.add(0, cur);
+            cur = parent[cur];
+        }
+        return new Path(nodes, dist[dst]);
+    }
+
+    private static final class Node implements Comparable<Node> {
+        final int u;
+        final long dist;
+        Node(int u, long dist) {
+            this.u = u;
+            this.dist = dist;
+        }
+        public int compareTo(Node o) {
+            return Long.compare(this.dist, o.dist);
+        }
+    }
+
+    private static final class Path implements Comparable<Path> {
+        final List<Integer> nodes;
+        final long cost;
+        Path(List<Integer> nodes, long cost) {
+            this.nodes = nodes;
+            this.cost = cost;
+        }
+        String key() {
+            return nodes.toString();
+        }
+        @Override
+        public int compareTo(Path o) {
+            int costCmp = Long.compare(this.cost, o.cost);
+            if (costCmp != 0) {
+                return costCmp;
+            }
+            // tie-break lexicographically on nodes
+            int minLength = Math.min(this.nodes.size(), o.nodes.size());
+            for (int i = 0; i < minLength; i++) {
+                int aNode = this.nodes.get(i);
+                int bNode = o.nodes.get(i);
+                if (aNode != bNode) {
+                    return Integer.compare(aNode, bNode);
+                }
+            }
+            return Integer.compare(this.nodes.size(), o.nodes.size());
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/YensKShortestPathsTest.java b/src/test/java/com/thealgorithms/graph/YensKShortestPathsTest.java
new file mode 100644
index 000000000000..1de37a310939
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/YensKShortestPathsTest.java
@@ -0,0 +1,76 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.List;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class YensKShortestPathsTest {
+
+    @Test
+    @DisplayName("Basic K-shortest paths on small directed graph")
+    void basicKPaths() {
+        // Graph (directed) with non-negative weights, -1 = no edge
+        // 0 -> 1 (1), 0 -> 2 (2), 1 -> 3 (1), 2 -> 3 (1), 0 -> 3 (5), 1 -> 2 (1)
+        int n = 4;
+        int[][] w = new int[n][n];
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < n; j++) {
+                w[i][j] = -1;
+            }
+        }
+        w[0][1] = 1;
+        w[0][2] = 2;
+        w[1][3] = 1;
+        w[2][3] = 1;
+        w[0][3] = 5;
+        w[1][2] = 1;
+
+        List<List<Integer>> paths = YensKShortestPaths.kShortestPaths(w, 0, 3, 3);
+        // Expected K=3 loopless shortest paths from 0 to 3, ordered by total cost:
+        // 1) 0-1-3 (cost 2)
+        // 2) 0-2-3 (cost 3)
+        // 3) 0-1-2-3 (cost 3) -> tie with 0-2-3; tie-broken lexicographically by nodes
+        assertEquals(3, paths.size());
+        assertEquals(List.of(0, 1, 3), paths.get(0));
+        assertEquals(List.of(0, 1, 2, 3), paths.get(1)); // lexicographically before [0,2,3]
+        assertEquals(List.of(0, 2, 3), paths.get(2));
+    }
+
+    @Test
+    @DisplayName("K larger than available paths returns only existing ones")
+    void kLargerThanAvailable() {
+        int[][] w = {{-1, 1, -1}, {-1, -1, 1}, {-1, -1, -1}};
+        // Only one simple path 0->1->2
+        List<List<Integer>> paths = YensKShortestPaths.kShortestPaths(w, 0, 2, 5);
+        assertEquals(1, paths.size());
+        assertEquals(List.of(0, 1, 2), paths.get(0));
+    }
+
+    @Test
+    @DisplayName("No path returns empty list")
+    void noPath() {
+        int[][] w = {{-1, -1}, {-1, -1}};
+        List<List<Integer>> paths = YensKShortestPaths.kShortestPaths(w, 0, 1, 3);
+        assertEquals(0, paths.size());
+    }
+
+    @Test
+    @DisplayName("Source equals destination returns trivial path")
+    void sourceEqualsDestination() {
+        int[][] w = {{-1, 1}, {-1, -1}};
+        List<List<Integer>> paths = YensKShortestPaths.kShortestPaths(w, 0, 0, 2);
+        // First path is [0]
+        assertEquals(1, paths.size());
+        assertEquals(List.of(0), paths.get(0));
+    }
+
+    @Test
+    @DisplayName("Negative weight entries (other than -1) are rejected")
+    void negativeWeightsRejected() {
+        int[][] w = {{-1, -2}, {-1, -1}};
+        assertThrows(IllegalArgumentException.class, () -> YensKShortestPaths.kShortestPaths(w, 0, 1, 2));
+    }
+}

From 3c61271ff74e8b24214dc38077f595124e57cff7 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 14 Oct 2025 10:43:12 +0200
Subject: [PATCH 1017/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 12.0.0 to 12.0.1 (#6775)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 12.0.0 to 12.0.1.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-12.0.0...checkstyle-12.0.1)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 12.0.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index e0e3516c08eb..9a7a205026ec 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>12.0.0</version>
+                    <version>12.0.1</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 87ad52c206a17551decb09bc25d0e523618d6888 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 14 Oct 2025 10:47:48 +0200
Subject: [PATCH 1018/1338] chore(deps): bump org.jacoco:jacoco-maven-plugin
 from 0.8.13 to 0.8.14 (#6776)

Bumps [org.jacoco:jacoco-maven-plugin](https://github.com/jacoco/jacoco) from 0.8.13 to 0.8.14.
- [Release notes](https://github.com/jacoco/jacoco/releases)
- [Commits](https://github.com/jacoco/jacoco/compare/v0.8.13...v0.8.14)

---
updated-dependencies:
- dependency-name: org.jacoco:jacoco-maven-plugin
  dependency-version: 0.8.14
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 9a7a205026ec..250fefd5073f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -82,7 +82,7 @@
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>
-                <version>0.8.13</version>
+                <version>0.8.14</version>
                 <executions>
                     <execution>
                         <goals>

From a9357102b3494a4ac04df587c4ea40c1135190e4 Mon Sep 17 00:00:00 2001
From: TejasSingh022 <157150137+TejasSingh022@users.noreply.github.com>
Date: Tue, 14 Oct 2025 14:23:02 +0530
Subject: [PATCH 1019/1338] Add TortoiseHareAlgo implementation with append,
 toString, and getMiddle methods (#6722)

* Create TortoiseHareAlgorithm.java

Implement TortoiseHareAlgo with append, getMiddle, and toString methods

- Added generic singly linked list with inner Node class
- Implemented append() to add elements
- Implemented getMiddle() using Tortoise-Hare approach
- Added toString() for readable list representation

* Create TortoiseHareAlgoTest.java

Add JUnit tests for TortoiseHareAlgo

- Verified append() and toString() output
- Tested getMiddle() for odd, even, and empty lists
- Ensured correct behavior and null handling

* Update README.md

Add TortoiseHareAlgo to linked list documentation

- Added TortoiseHareAlgo.java to file descriptions
- Described its purpose: finding middle element using Tortoise-Hare algorithm

* Rename TortoiseHareAlgorithm.java to TortoiseHareAlgo.java

Fixed build error

* Update TortoiseHareAlgoTest.java

Fixed line formatting build error

* Update TortoiseHareAlgoTest.java

Fixed line formatting build error

* Update TortoiseHareAlgo.java

Added {} after if statement instead of directly writing statement

* Update TortoiseHareAlgo.java

Fixed line formatting build error

* Update TortoiseHareAlgo.java

Added {} after if statement instead of directly writing statement

* Update TortoiseHareAlgoTest.java

Replace .* import with specific imports

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../datastructures/lists/README.md            |  1 +
 .../lists/TortoiseHareAlgo.java               | 63 +++++++++++++++++++
 .../lists/TortoiseHareAlgoTest.java           | 46 ++++++++++++++
 3 files changed, 110 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/lists/TortoiseHareAlgo.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/TortoiseHareAlgoTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/README.md b/src/main/java/com/thealgorithms/datastructures/lists/README.md
index 6aefa4c98e6d..5a19c3bfa990 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/README.md
+++ b/src/main/java/com/thealgorithms/datastructures/lists/README.md
@@ -30,3 +30,4 @@ The `next` variable points to the next node in the data structure and value stor
 6. `MergeKSortedLinkedlist.java` : Merges K sorted linked list with mergesort (mergesort is also the most efficient sorting algorithm for linked list).
 7. `RandomNode.java` : Selects a random node from given linked list and diplays it.
 8. `SkipList.java` : Data Structure used for storing a sorted list of elements with help of a Linked list hierarchy that connects to subsequences of elements.
+9. `TortoiseHareAlgo.java` : Finds the middle element of a linked list using the fast and slow pointer (Tortoise-Hare) algorithm.
diff --git a/src/main/java/com/thealgorithms/datastructures/lists/TortoiseHareAlgo.java b/src/main/java/com/thealgorithms/datastructures/lists/TortoiseHareAlgo.java
new file mode 100644
index 000000000000..9d803003c658
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/lists/TortoiseHareAlgo.java
@@ -0,0 +1,63 @@
+package com.thealgorithms.datastructures.lists;
+
+public class TortoiseHareAlgo<E> {
+    static final class Node<E> {
+        Node<E> next;
+        E value;
+
+        private Node(E value, Node<E> next) {
+            this.value = value;
+            this.next = next;
+        }
+    }
+
+    private Node<E> head = null;
+
+    public TortoiseHareAlgo() {
+        head = null;
+    }
+
+    public void append(E value) {
+        Node<E> newNode = new Node<>(value, null);
+        if (head == null) {
+            head = newNode;
+            return;
+        }
+        Node<E> current = head;
+        while (current.next != null) {
+            current = current.next;
+        }
+        current.next = newNode;
+    }
+
+    public E getMiddle() {
+        if (head == null) {
+            return null;
+        }
+
+        Node<E> slow = head;
+        Node<E> fast = head;
+
+        while (fast != null && fast.next != null) {
+            slow = slow.next;
+            fast = fast.next.next;
+        }
+
+        return slow.value;
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder("[");
+        Node<E> current = head;
+        while (current != null) {
+            sb.append(current.value);
+            if (current.next != null) {
+                sb.append(", ");
+            }
+            current = current.next;
+        }
+        sb.append("]");
+        return sb.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/TortoiseHareAlgoTest.java b/src/test/java/com/thealgorithms/datastructures/lists/TortoiseHareAlgoTest.java
new file mode 100644
index 000000000000..2804534c988c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/TortoiseHareAlgoTest.java
@@ -0,0 +1,46 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+class TortoiseHareAlgoTest {
+
+    @Test
+    void testAppendAndToString() {
+        TortoiseHareAlgo<Integer> list = new TortoiseHareAlgo<>();
+        list.append(10);
+        list.append(20);
+        list.append(30);
+        assertEquals("[10, 20, 30]", list.toString());
+    }
+
+    @Test
+    void testGetMiddleOdd() {
+        TortoiseHareAlgo<Integer> list = new TortoiseHareAlgo<>();
+        list.append(1);
+        list.append(2);
+        list.append(3);
+        list.append(4);
+        list.append(5);
+        assertEquals(3, list.getMiddle());
+    }
+
+    @Test
+    void testGetMiddleEven() {
+        TortoiseHareAlgo<Integer> list = new TortoiseHareAlgo<>();
+        list.append(1);
+        list.append(2);
+        list.append(3);
+        list.append(4);
+        assertEquals(3, list.getMiddle()); // returns second middle
+    }
+
+    @Test
+    void testEmptyList() {
+        TortoiseHareAlgo<Integer> list = new TortoiseHareAlgo<>();
+        assertNull(list.getMiddle());
+        assertEquals("[]", list.toString());
+    }
+}

From b316dcf1c61175a4e55069c2056525135fe3ce02 Mon Sep 17 00:00:00 2001
From: Priyanshu Kumar Singh <priyanshu1303d@gmail.com>
Date: Tue, 14 Oct 2025 14:26:21 +0530
Subject: [PATCH 1020/1338] [FEAT] Implement Flattening MultiLevel LinkedList
 (#6670)

[FEAT] Implement Flattening Multilevel LinkedList

Co-authored-by: Priyanshu1303d <priyanshu130d@gmail.com>
---
 .../lists/FlattenMultilevelLinkedList.java    |  92 ++++++++++++++
 .../FlattenMultilevelLinkedListTest.java      | 112 ++++++++++++++++++
 2 files changed, 204 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/lists/FlattenMultilevelLinkedList.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/FlattenMultilevelLinkedListTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/FlattenMultilevelLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/FlattenMultilevelLinkedList.java
new file mode 100644
index 000000000000..3c4106f178b9
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/lists/FlattenMultilevelLinkedList.java
@@ -0,0 +1,92 @@
+package com.thealgorithms.datastructures.lists;
+/**
+ * Implements an algorithm to flatten a multilevel linked list.
+ *
+ * In this specific problem structure, each node has a `next` pointer (to the
+ * next node at the same level) and a `child` pointer (which points to the head
+ * of another sorted linked list). The goal is to merge all these lists into a
+ * single, vertically sorted linked list using the `child` pointer.
+ *
+ * The approach is a recursive one that leverages a merge utility, similar to
+ * the merge step in Merge Sort. It recursively flattens the list starting from
+ * the rightmost node and merges each node's child list with the already
+ * flattened list to its right.
+ * @see <a href="https://www.geeksforgeeks.org/flattening-a-linked-list/">GeeksforGeeks: Flattening a Linked List</a>
+ */
+public final class FlattenMultilevelLinkedList {
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private FlattenMultilevelLinkedList() {
+    }
+    /**
+     * Node represents an element in the multilevel linked list. It contains the
+     * integer data, a reference to the next node at the same level, and a
+     * reference to the head of a child list.
+     */
+    static class Node {
+        int data;
+        Node next;
+        Node child;
+
+        Node(int data) {
+            this.data = data;
+            this.next = null;
+            this.child = null;
+        }
+    }
+
+    /**
+     * Merges two sorted linked lists (connected via the `child` pointer).
+     * This is a helper function for the main flatten algorithm.
+     *
+     * @param a The head of the first sorted list.
+     * @param b The head of the second sorted list.
+     * @return The head of the merged sorted list.
+     */
+    private static Node merge(Node a, Node b) {
+        // If one of the lists is empty, return the other.
+        if (a == null) {
+            return b;
+        }
+        if (b == null) {
+            return a;
+        }
+
+        Node result;
+
+        // Choose the smaller value as the new head.
+        if (a.data < b.data) {
+            result = a;
+            result.child = merge(a.child, b);
+        } else {
+            result = b;
+            result.child = merge(a, b.child);
+        }
+        result.next = null; // Ensure the merged list has no `next` pointers.
+        return result;
+    }
+
+    /**
+     * Flattens a multilevel linked list into a single sorted list.
+     * The flattened list is connected using the `child` pointers.
+     *
+     * @param head The head of the top-level list (connected via `next` pointers).
+     * @return The head of the fully flattened and sorted list.
+     */
+    public static Node flatten(Node head) {
+        // Base case: if the list is empty or has only one node, it's already flattened.
+        if (head == null || head.next == null) {
+            return head;
+        }
+
+        // Recursively flatten the list starting from the next node.
+        head.next = flatten(head.next);
+
+        // Now, merge the current list (head's child list) with the flattened rest of the list.
+        head = merge(head, head.next);
+
+        // Return the head of the fully merged list.
+        return head;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/FlattenMultilevelLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/FlattenMultilevelLinkedListTest.java
new file mode 100644
index 000000000000..667f9fcf5700
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/FlattenMultilevelLinkedListTest.java
@@ -0,0 +1,112 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+/**
+ * Unit tests for the FlattenMultilevelLinkedList class.
+ * This class tests the flattening logic with various list structures,
+ * including null lists, simple lists, and complex multilevel lists.
+ */
+final class FlattenMultilevelLinkedListTest {
+
+    // A helper function to convert a flattened list (connected by child pointers)
+    // into a standard Java List for easy comparison.
+    private List<Integer> toList(FlattenMultilevelLinkedList.Node head) {
+        List<Integer> list = new ArrayList<>();
+        FlattenMultilevelLinkedList.Node current = head;
+        while (current != null) {
+            list.add(current.data);
+            current = current.child;
+        }
+        return list;
+    }
+
+    @Test
+    @DisplayName("Test with a null list")
+    void testFlattenNullList() {
+        assertNull(FlattenMultilevelLinkedList.flatten(null));
+    }
+
+    @Test
+    @DisplayName("Test with a simple, single-level list")
+    void testFlattenSingleLevelList() {
+        // Create a simple list: 1 -> 2 -> 3
+        FlattenMultilevelLinkedList.Node head = new FlattenMultilevelLinkedList.Node(1);
+        head.next = new FlattenMultilevelLinkedList.Node(2);
+        head.next.next = new FlattenMultilevelLinkedList.Node(3);
+
+        // Flatten the list
+        FlattenMultilevelLinkedList.Node flattenedHead = FlattenMultilevelLinkedList.flatten(head);
+
+        // Expected output: 1 -> 2 -> 3 (vertically)
+        List<Integer> expected = List.of(1, 2, 3);
+        assertEquals(expected, toList(flattenedHead));
+    }
+
+    @Test
+    @DisplayName("Test with a complex multilevel list")
+    void testFlattenComplexMultilevelList() {
+        // Create the multilevel structure from the problem description
+        // 5 -> 10 -> 19 -> 28
+        // |    |     |     |
+        // 7    20    22    35
+        // |          |     |
+        // 8          50    40
+        // |                |
+        // 30               45
+        FlattenMultilevelLinkedList.Node head = new FlattenMultilevelLinkedList.Node(5);
+        head.child = new FlattenMultilevelLinkedList.Node(7);
+        head.child.child = new FlattenMultilevelLinkedList.Node(8);
+        head.child.child.child = new FlattenMultilevelLinkedList.Node(30);
+
+        head.next = new FlattenMultilevelLinkedList.Node(10);
+        head.next.child = new FlattenMultilevelLinkedList.Node(20);
+
+        head.next.next = new FlattenMultilevelLinkedList.Node(19);
+        head.next.next.child = new FlattenMultilevelLinkedList.Node(22);
+        head.next.next.child.child = new FlattenMultilevelLinkedList.Node(50);
+
+        head.next.next.next = new FlattenMultilevelLinkedList.Node(28);
+        head.next.next.next.child = new FlattenMultilevelLinkedList.Node(35);
+        head.next.next.next.child.child = new FlattenMultilevelLinkedList.Node(40);
+        head.next.next.next.child.child.child = new FlattenMultilevelLinkedList.Node(45);
+
+        // Flatten the list
+        FlattenMultilevelLinkedList.Node flattenedHead = FlattenMultilevelLinkedList.flatten(head);
+
+        // Expected sorted output
+        List<Integer> expected = List.of(5, 7, 8, 10, 19, 20, 22, 28, 30, 35, 40, 45, 50);
+        assertEquals(expected, toList(flattenedHead));
+    }
+
+    @Test
+    @DisplayName("Test with some empty child lists")
+    void testFlattenWithEmptyChildLists() {
+        // Create a list: 5 -> 10 -> 12
+        // |           |
+        // 7           11
+        // |
+        // 9
+        FlattenMultilevelLinkedList.Node head = new FlattenMultilevelLinkedList.Node(5);
+        head.child = new FlattenMultilevelLinkedList.Node(7);
+        head.child.child = new FlattenMultilevelLinkedList.Node(9);
+
+        head.next = new FlattenMultilevelLinkedList.Node(10); // No child list
+        head.next.child = null;
+
+        head.next.next = new FlattenMultilevelLinkedList.Node(12);
+        head.next.next.child = new FlattenMultilevelLinkedList.Node(16);
+
+        // Flatten the list
+        FlattenMultilevelLinkedList.Node flattenedHead = FlattenMultilevelLinkedList.flatten(head);
+
+        // Expected sorted output
+        List<Integer> expected = List.of(5, 7, 9, 10, 12, 16);
+        assertEquals(expected, toList(flattenedHead));
+    }
+}

From b50d1d017b57d5b57fd4d4aec8e70e64d2701306 Mon Sep 17 00:00:00 2001
From: Shivam Singh <dreamyshivam01@gmail.com>
Date: Tue, 14 Oct 2025 22:52:15 +0530
Subject: [PATCH 1021/1338] Added Sentinel Linear Search . (#6671)

* Added Sentinel Linear Search .

* Fixed linter error

* Fixed linter errors

* Fixed linter errors in test fike

* Fixed linter errors in test file

* Fixed linter errors
---
 .../searches/SentinelLinearSearch.java        |  99 ++++++++
 .../searches/SentinelLinearSearchTest.java    | 225 ++++++++++++++++++
 2 files changed, 324 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/searches/SentinelLinearSearch.java
 create mode 100644 src/test/java/com/thealgorithms/searches/SentinelLinearSearchTest.java

diff --git a/src/main/java/com/thealgorithms/searches/SentinelLinearSearch.java b/src/main/java/com/thealgorithms/searches/SentinelLinearSearch.java
new file mode 100644
index 000000000000..1a5903a5d134
--- /dev/null
+++ b/src/main/java/com/thealgorithms/searches/SentinelLinearSearch.java
@@ -0,0 +1,99 @@
+package com.thealgorithms.searches;
+
+import com.thealgorithms.devutils.searches.SearchAlgorithm;
+
+/**
+ * Sentinel Linear Search is a variation of linear search that eliminates the
+ * need to check the array bounds in each iteration by placing the search key
+ * at the end of the array as a sentinel value.
+ *
+ * <p>
+ * The algorithm works by:
+ * 1. Storing the last element of the array
+ * 2. Placing the search key at the last position (sentinel)
+ * 3. Searching from the beginning without bound checking
+ * 4. If found before the last position, return the index
+ * 5. If found at the last position, check if it was originally there
+ *
+ * <p>
+ * Time Complexity:
+ * - Best case: O(1) - when the element is at the first position
+ * - Average case: O(n) - when the element is in the middle
+ * - Worst case: O(n) - when the element is not present
+ *
+ * <p>
+ * Space Complexity: O(1) - only uses constant extra space
+ *
+ * <p>
+ * Advantages over regular linear search:
+ * - Reduces the number of comparisons by eliminating bound checking
+ * - Slightly more efficient in practice due to fewer conditional checks
+ *
+ * @author TheAlgorithms Contributors
+ * @see LinearSearch
+ * @see SearchAlgorithm
+ */
+public class SentinelLinearSearch implements SearchAlgorithm {
+    /**
+     * Performs sentinel linear search on the given array.
+     *
+     * @param array the array to search in
+     * @param key the element to search for
+     * @param <T> the type of elements in the array, must be Comparable
+     * @return the index of the first occurrence of the key, or -1 if not found
+     * @throws IllegalArgumentException if the array is null
+     */
+    @Override
+    public <T extends Comparable<T>> int find(T[] array, T key) {
+        if (array == null) {
+            throw new IllegalArgumentException("Array cannot be null");
+        }
+
+        if (array.length == 0) {
+            return -1;
+        }
+
+        if (key == null) {
+            return findNull(array);
+        }
+
+        // Store the last element
+        T lastElement = array[array.length - 1];
+
+        // Place the sentinel (search key) at the end
+        array[array.length - 1] = key;
+
+        int i = 0;
+        // Search without bound checking since sentinel guarantees we'll find the key
+        while (array[i].compareTo(key) != 0) {
+            i++;
+        }
+
+        // Restore the original last element
+        array[array.length - 1] = lastElement;
+
+        // Check if we found the key before the sentinel position
+        // or if the original last element was the key we were looking for
+        if (i < array.length - 1 || (lastElement != null && lastElement.compareTo(key) == 0)) {
+            return i;
+        }
+
+        return -1; // Key not found
+    }
+
+    /**
+     * Helper method to find null values in the array.
+     *
+     * @param array the array to search in
+     * @param <T> the type of elements in the array
+     * @return the index of the first null element, or -1 if not found
+     */
+    private <T extends Comparable<T>> int findNull(T[] array) {
+        for (int i = 0; i < array.length; i++) {
+            if (array[i] == null) {
+                return i;
+            }
+        }
+        return -1;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/searches/SentinelLinearSearchTest.java b/src/test/java/com/thealgorithms/searches/SentinelLinearSearchTest.java
new file mode 100644
index 000000000000..0da8e1c83997
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/SentinelLinearSearchTest.java
@@ -0,0 +1,225 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.Random;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the SentinelLinearSearch class.
+ */
+class SentinelLinearSearchTest {
+
+    /**
+     * Test for finding an element present in the array.
+     */
+    @Test
+    void testSentinelLinearSearchFound() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 5; // Element to find
+        assertEquals(5, sentinelLinearSearch.find(array, key), "The index of the found element should be 5.");
+    }
+
+    /**
+     * Test for finding the first element in the array.
+     */
+    @Test
+    void testSentinelLinearSearchFirstElement() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 0; // First element
+        assertEquals(0, sentinelLinearSearch.find(array, key), "The index of the first element should be 0.");
+    }
+
+    /**
+     * Test for finding the last element in the array.
+     */
+    @Test
+    void testSentinelLinearSearchLastElement() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 10; // Last element
+        assertEquals(10, sentinelLinearSearch.find(array, key), "The index of the last element should be 10.");
+    }
+
+    /**
+     * Test for finding an element not present in the array.
+     */
+    @Test
+    void testSentinelLinearSearchNotFound() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = -1; // Element not in the array
+        assertEquals(-1, sentinelLinearSearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for finding an element in an empty array.
+     */
+    @Test
+    void testSentinelLinearSearchEmptyArray() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {}; // Empty array
+        Integer key = 1; // Key not present
+        assertEquals(-1, sentinelLinearSearch.find(array, key), "The element should not be found in an empty array.");
+    }
+
+    /**
+     * Test for finding an element in a single-element array when present.
+     */
+    @Test
+    void testSentinelLinearSearchSingleElementFound() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {42}; // Single element array
+        Integer key = 42; // Element present
+        assertEquals(0, sentinelLinearSearch.find(array, key), "The element should be found at index 0.");
+    }
+
+    /**
+     * Test for finding an element in a single-element array when not present.
+     */
+    @Test
+    void testSentinelLinearSearchSingleElementNotFound() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {42}; // Single element array
+        Integer key = 24; // Element not present
+        assertEquals(-1, sentinelLinearSearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for finding multiple occurrences of the same element in the array.
+     */
+    @Test
+    void testSentinelLinearSearchMultipleOccurrences() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {1, 2, 3, 4, 5, 3, 6, 7, 3}; // 3 occurs multiple times
+        Integer key = 3; // Key to find
+        assertEquals(2, sentinelLinearSearch.find(array, key), "The index of the first occurrence of the element should be 2.");
+    }
+
+    /**
+     * Test for finding an element in a large array.
+     */
+    @Test
+    void testSentinelLinearSearchLargeArray() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = new Integer[1000];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = i; // Fill the array with integers 0 to 999
+        }
+        Integer key = 256; // Present in the array
+        assertEquals(256, sentinelLinearSearch.find(array, key), "The index of the found element should be 256.");
+    }
+
+    /**
+     * Test for finding an element in a large array when it is not present.
+     */
+    @Test
+    void testSentinelLinearSearchLargeArrayNotFound() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = new Integer[1000];
+        for (int i = 0; i < array.length; i++) {
+            array[i] = i; // Fill the array with integers 0 to 999
+        }
+        Integer key = 1001; // Key not present
+        assertEquals(-1, sentinelLinearSearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for performance with random large array.
+     */
+    @Test
+    void testSentinelLinearSearchRandomArray() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Random random = new Random();
+        Integer[] array = random.ints(0, 1000).distinct().limit(1000).boxed().toArray(Integer[] ::new);
+        Integer key = array[random.nextInt(array.length)]; // Key should be in the array
+        assertEquals(java.util.Arrays.asList(array).indexOf(key), sentinelLinearSearch.find(array, key), "The index of the found element should match.");
+    }
+
+    /**
+     * Test for handling null array.
+     */
+    @Test
+    void testSentinelLinearSearchNullArray() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = null; // Null array
+        Integer key = 1; // Any key
+        assertThrows(IllegalArgumentException.class, () -> sentinelLinearSearch.find(array, key), "Should throw IllegalArgumentException for null array.");
+    }
+
+    /**
+     * Test for handling null key in array with null elements.
+     */
+    @Test
+    void testSentinelLinearSearchNullKey() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {1, null, 3, 4, null}; // Array with null elements
+        Integer key = null; // Null key
+        assertEquals(1, sentinelLinearSearch.find(array, key), "The index of the first null element should be 1.");
+    }
+
+    /**
+     * Test for handling null key when not present in array.
+     */
+    @Test
+    void testSentinelLinearSearchNullKeyNotFound() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {1, 2, 3, 4, 5}; // Array without null elements
+        Integer key = null; // Null key
+        assertEquals(-1, sentinelLinearSearch.find(array, key), "Null key should not be found in array without null elements.");
+    }
+
+    /**
+     * Test with String array to verify generic functionality.
+     */
+    @Test
+    void testSentinelLinearSearchStringArray() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        String[] array = {"apple", "banana", "cherry", "date", "elderberry"};
+        String key = "cherry"; // Element to find
+        assertEquals(2, sentinelLinearSearch.find(array, key), "The index of 'cherry' should be 2.");
+    }
+
+    /**
+     * Test with String array when element not found.
+     */
+    @Test
+    void testSentinelLinearSearchStringArrayNotFound() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        String[] array = {"apple", "banana", "cherry", "date", "elderberry"};
+        String key = "grape"; // Element not in array
+        assertEquals(-1, sentinelLinearSearch.find(array, key), "The element 'grape' should not be found in the array.");
+    }
+
+    /**
+     * Test that the original array is not modified after search.
+     */
+    @Test
+    void testSentinelLinearSearchArrayIntegrity() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {1, 2, 3, 4, 5};
+        Integer[] originalArray = array.clone(); // Keep a copy of the original
+        Integer key = 3; // Element to find
+
+        sentinelLinearSearch.find(array, key);
+
+        // Verify array is unchanged
+        for (int i = 0; i < array.length; i++) {
+            assertEquals(originalArray[i], array[i], "Array should remain unchanged after search.");
+        }
+    }
+
+    /**
+     * Test edge case where the key is the same as the last element.
+     */
+    @Test
+    void testSentinelLinearSearchKeyEqualsLastElement() {
+        SentinelLinearSearch sentinelLinearSearch = new SentinelLinearSearch();
+        Integer[] array = {1, 2, 3, 4, 5, 3}; // Last element is 3, and 3 also appears earlier
+        Integer key = 3; // Key equals last element
+        assertEquals(2, sentinelLinearSearch.find(array, key), "Should find the first occurrence at index 2, not the last.");
+    }
+}

From ce6f7311f75d1d23078ba2b7179a625e96b8c37d Mon Sep 17 00:00:00 2001
From: Microindole <1513979779@qq.com>
Date: Wed, 15 Oct 2025 01:29:03 +0800
Subject: [PATCH 1022/1338] feat: Add RLE and Shannon-Fano compression
 algorithms (#6779)

* feat: Add RLE and Shannon-Fano compression algorithms

* Fix: Resolve CI failures for compression algorithms

* chore: trigger CI rebuild
---
 .../compression/RunLengthEncoding.java        |  87 ++++++++++
 .../compression/ShannonFano.java              | 159 ++++++++++++++++++
 .../compression/RunLengthEncodingTest.java    |  90 ++++++++++
 .../compression/ShannonFanoTest.java          |  71 ++++++++
 4 files changed, 407 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/compression/RunLengthEncoding.java
 create mode 100644 src/main/java/com/thealgorithms/compression/ShannonFano.java
 create mode 100644 src/test/java/com/thealgorithms/compression/RunLengthEncodingTest.java
 create mode 100644 src/test/java/com/thealgorithms/compression/ShannonFanoTest.java

diff --git a/src/main/java/com/thealgorithms/compression/RunLengthEncoding.java b/src/main/java/com/thealgorithms/compression/RunLengthEncoding.java
new file mode 100644
index 000000000000..8d065f4648df
--- /dev/null
+++ b/src/main/java/com/thealgorithms/compression/RunLengthEncoding.java
@@ -0,0 +1,87 @@
+package com.thealgorithms.compression;
+
+/**
+ * An implementation of the Run-Length Encoding (RLE) algorithm.
+ *
+ * <p>Run-Length Encoding is a simple form of lossless data compression in which
+ * runs of data (sequences in which the same data value occurs in many
+ * consecutive data elements) are stored as a single data value and count,
+ * rather than as the original run.
+ *
+ * <p>This implementation provides methods for both compressing and decompressing
+ * a string. For example:
+ * <ul>
+ * <li>Compressing "AAAABBBCCDAA" results in "4A3B2C1D2A".</li>
+ * <li>Decompressing "4A3B2C1D2A" results in "AAAABBBCCDAA".</li>
+ * </ul>
+ *
+ * <p>Time Complexity: O(n) for both compression and decompression, where n is the
+ * length of the input string.
+ *
+ * <p>References:
+ * <ul>
+ * <li><a href="https://en.wikipedia.org/wiki/Run-length_encoding">Wikipedia: Run-length encoding</a></li>
+ * </ul>
+ */
+public final class RunLengthEncoding {
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private RunLengthEncoding() {
+    }
+
+    /**
+     * Compresses a string using the Run-Length Encoding algorithm.
+     *
+     * @param text The string to be compressed. Must not be null.
+     * @return The compressed string. Returns an empty string if the input is empty.
+     */
+    public static String compress(String text) {
+        if (text == null || text.isEmpty()) {
+            return "";
+        }
+
+        StringBuilder compressed = new StringBuilder();
+        int count = 1;
+
+        for (int i = 0; i < text.length(); i++) {
+            // Check if it's the last character or if the next character is different
+            if (i == text.length() - 1 || text.charAt(i) != text.charAt(i + 1)) {
+                compressed.append(count);
+                compressed.append(text.charAt(i));
+                count = 1; // Reset count for the new character
+            } else {
+                count++;
+            }
+        }
+        return compressed.toString();
+    }
+
+    /**
+     * Decompresses a string that was compressed using the Run-Length Encoding algorithm.
+     *
+     * @param compressedText The compressed string. Must not be null.
+     * @return The original, uncompressed string.
+     */
+    public static String decompress(String compressedText) {
+        if (compressedText == null || compressedText.isEmpty()) {
+            return "";
+        }
+
+        StringBuilder decompressed = new StringBuilder();
+        int count = 0;
+
+        for (char ch : compressedText.toCharArray()) {
+            if (Character.isDigit(ch)) {
+                // Build the number for runs of 10 or more (e.g., "12A")
+                count = count * 10 + ch - '0';
+            } else {
+                // Append the character 'count' times
+                decompressed.append(String.valueOf(ch).repeat(Math.max(0, count)));
+                count = 0; // Reset count for the next sequence
+            }
+        }
+        return decompressed.toString();
+    }
+}
diff --git a/src/main/java/com/thealgorithms/compression/ShannonFano.java b/src/main/java/com/thealgorithms/compression/ShannonFano.java
new file mode 100644
index 000000000000..aa5d7ad91b2f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/compression/ShannonFano.java
@@ -0,0 +1,159 @@
+package com.thealgorithms.compression;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * An implementation of the Shannon-Fano algorithm for generating prefix codes.
+ *
+ * <p>Shannon-Fano coding is an entropy encoding technique for lossless data
+ * compression. It assigns variable-length codes to symbols based on their
+ * frequencies of occurrence. It is a precursor to Huffman coding and works by
+ * recursively partitioning a sorted list of symbols into two sub-lists with
+ * nearly equal total frequencies.
+ *
+ * <p>The algorithm works as follows:
+ * <ol>
+ * <li>Count the frequency of each symbol in the input data.</li>
+ * <li>Sort the symbols in descending order of their frequencies.</li>
+ * <li>Recursively divide the list of symbols into two parts with sums of
+ * frequencies as close as possible to each other.</li>
+ * <li>Assign a '0' bit to the codes in the first part and a '1' bit to the codes
+ * in the second part.</li>
+ * <li>Repeat the process for each part until a part contains only one symbol.</li>
+ * </ol>
+ *
+ * <p>Time Complexity: O(n^2) in this implementation due to the partitioning logic,
+ * or O(n log n) if a more optimized partitioning strategy is used.
+ * Sorting takes O(n log n), where n is the number of unique symbols.
+ *
+ * <p>References:
+ * <ul>
+ * <li><a href="https://en.wikipedia.org/wiki/Shannonâ€"Fano_coding">Wikipedia: Shannonâ€"Fano coding</a></li>
+ * </ul>
+ */
+public final class ShannonFano {
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private ShannonFano() {
+    }
+
+    /**
+     * A private inner class to represent a symbol and its frequency.
+     * Implements Comparable to allow sorting based on frequency.
+     */
+    private static class Symbol implements Comparable<Symbol> {
+        final char character;
+        final int frequency;
+        String code = "";
+
+        Symbol(char character, int frequency) {
+            this.character = character;
+            this.frequency = frequency;
+        }
+
+        @Override
+        public int compareTo(Symbol other) {
+            return Integer.compare(other.frequency, this.frequency); // Sort descending
+        }
+    }
+
+    /**
+     * Generates Shannon-Fano codes for the symbols in a given text.
+     *
+     * @param text The input string for which to generate codes. Must not be null.
+     * @return A map where keys are characters and values are their corresponding Shannon-Fano codes.
+     */
+    public static Map<Character, String> generateCodes(String text) {
+        if (text == null || text.isEmpty()) {
+            return Collections.emptyMap();
+        }
+
+        Map<Character, Integer> frequencyMap = new HashMap<>();
+        for (char c : text.toCharArray()) {
+            frequencyMap.put(c, frequencyMap.getOrDefault(c, 0) + 1);
+        }
+
+        List<Symbol> symbols = new ArrayList<>();
+        for (Map.Entry<Character, Integer> entry : frequencyMap.entrySet()) {
+            symbols.add(new Symbol(entry.getKey(), entry.getValue()));
+        }
+
+        Collections.sort(symbols);
+
+        // Special case: only one unique symbol
+        if (symbols.size() == 1) {
+            symbols.getFirst().code = "0";
+        } else {
+            buildCodeTree(symbols, 0, symbols.size() - 1, "");
+        }
+
+        return symbols.stream().collect(Collectors.toMap(s -> s.character, s -> s.code));
+    }
+
+    /**
+     * Recursively builds the Shannon-Fano code tree by partitioning the list of symbols.
+     * Uses index-based approach to avoid sublist creation issues.
+     *
+     * @param symbols The sorted list of symbols to be processed.
+     * @param start   The start index of the current partition.
+     * @param end     The end index of the current partition (inclusive).
+     * @param prefix  The current prefix code being built for the symbols in this partition.
+     */
+    private static void buildCodeTree(List<Symbol> symbols, int start, int end, String prefix) {
+        // The initial check in generateCodes ensures start <= end is always true here.
+        // The base case is when a partition has only one symbol.
+        if (start == end) {
+            symbols.get(start).code = prefix;
+            return;
+        }
+
+        // Find the optimal split point
+        int splitIndex = findSplitIndex(symbols, start, end);
+
+        // Recursively process left and right partitions with updated prefixes
+        buildCodeTree(symbols, start, splitIndex, prefix + "0");
+        buildCodeTree(symbols, splitIndex + 1, end, prefix + "1");
+    }
+
+    /**
+     * Finds the index that splits the range into two parts with the most balanced frequency sums.
+     * This method tries every possible split point and returns the index that minimizes the
+     * absolute difference between the two partition sums.
+     *
+     * @param symbols The sorted list of symbols.
+     * @param start   The start index of the range.
+     * @param end     The end index of the range (inclusive).
+     * @return The index of the last element in the first partition.
+     */
+    private static int findSplitIndex(List<Symbol> symbols, int start, int end) {
+        // Calculate total frequency for the entire range
+        long totalFrequency = 0;
+        for (int i = start; i <= end; i++) {
+            totalFrequency += symbols.get(i).frequency;
+        }
+
+        long leftSum = 0;
+        long minDifference = Long.MAX_VALUE;
+        int splitIndex = start;
+
+        // Try every possible split point and find the one with minimum difference
+        for (int i = start; i < end; i++) {
+            leftSum += symbols.get(i).frequency;
+            long rightSum = totalFrequency - leftSum;
+            long difference = Math.abs(leftSum - rightSum);
+
+            if (difference < minDifference) {
+                minDifference = difference;
+                splitIndex = i;
+            }
+        }
+        return splitIndex;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/compression/RunLengthEncodingTest.java b/src/test/java/com/thealgorithms/compression/RunLengthEncodingTest.java
new file mode 100644
index 000000000000..049a7fac9ae9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/compression/RunLengthEncodingTest.java
@@ -0,0 +1,90 @@
+package com.thealgorithms.compression;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class RunLengthEncodingTest {
+
+    @Test
+    void testNullInputs() {
+        // Test that a null input to compress returns an empty string
+        assertEquals("", RunLengthEncoding.compress(null));
+
+        // Test that a null input to decompress returns an empty string
+        assertEquals("", RunLengthEncoding.decompress(null));
+    }
+
+    @Test
+    void testCompressionSimple() {
+        // Test a typical string with multiple runs
+        String input = "AAAABBBCCDAA";
+        String expected = "4A3B2C1D2A";
+        assertEquals(expected, RunLengthEncoding.compress(input));
+    }
+
+    @Test
+    void testCompressionWithNoRuns() {
+        // Test a string with no consecutive characters
+        String input = "ABCDE";
+        String expected = "1A1B1C1D1E";
+        assertEquals(expected, RunLengthEncoding.compress(input));
+    }
+
+    @Test
+    void testCompressionEdgeCases() {
+        // Test with an empty string
+        assertEquals("", RunLengthEncoding.compress(""));
+
+        // Test with a single character
+        assertEquals("1A", RunLengthEncoding.compress("A"));
+
+        // Test with a long run of a single character
+        assertEquals("10Z", RunLengthEncoding.compress("ZZZZZZZZZZ"));
+    }
+
+    @Test
+    void testDecompressionSimple() {
+        // Test decompression of a typical RLE string
+        String input = "4A3B2C1D2A";
+        String expected = "AAAABBBCCDAA";
+        assertEquals(expected, RunLengthEncoding.decompress(input));
+    }
+
+    @Test
+    void testDecompressionWithNoRuns() {
+        // Test decompression of a string with single characters
+        String input = "1A1B1C1D1E";
+        String expected = "ABCDE";
+        assertEquals(expected, RunLengthEncoding.decompress(input));
+    }
+
+    @Test
+    void testDecompressionWithMultiDigitCount() {
+        // Test decompression where a run count is greater than 9
+        String input = "12A1B3C";
+        String expected = "AAAAAAAAAAAABCCC";
+        assertEquals(expected, RunLengthEncoding.decompress(input));
+    }
+
+    @Test
+    void testDecompressionEdgeCases() {
+        // Test with an empty string
+        assertEquals("", RunLengthEncoding.decompress(""));
+
+        // Test with a single character run
+        assertEquals("A", RunLengthEncoding.decompress("1A"));
+    }
+
+    @Test
+    void testSymmetry() {
+        // Test that compressing and then decompressing returns the original string
+        String original1 = "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB";
+        String compressed = RunLengthEncoding.compress(original1);
+        String decompressed = RunLengthEncoding.decompress(compressed);
+        assertEquals(original1, decompressed);
+
+        String original2 = "A";
+        assertEquals(original2, RunLengthEncoding.decompress(RunLengthEncoding.compress(original2)));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/compression/ShannonFanoTest.java b/src/test/java/com/thealgorithms/compression/ShannonFanoTest.java
new file mode 100644
index 000000000000..ce34088dacca
--- /dev/null
+++ b/src/test/java/com/thealgorithms/compression/ShannonFanoTest.java
@@ -0,0 +1,71 @@
+package com.thealgorithms.compression;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Map;
+import org.junit.jupiter.api.Test;
+
+class ShannonFanoTest {
+
+    @Test
+    void testNullInput() {
+        // Test with a null string, should return an empty map
+        assertTrue(ShannonFano.generateCodes(null).isEmpty());
+    }
+
+    @Test
+    void testSimpleString() {
+        // A simple string to test basic code generation
+        String text = "AAABBC";
+        Map<Character, String> codes = ShannonFano.generateCodes(text);
+
+        assertEquals(3, codes.size());
+        assertEquals("0", codes.get('A'));
+        assertEquals("10", codes.get('B'));
+        assertEquals("11", codes.get('C'));
+    }
+
+    @Test
+    void testExampleFromStringIssue() {
+        // Example from the original issue proposal: A:15, B:7, C:6, D:6, E:5
+        // The code finds a more optimal split: {A,B} | {C,D,E} -> |22-17|=5
+        // instead of {A} | {B,C,D,E} -> |15-24|=9.
+        String text = "AAAAAAAAAAAAAAABBBBBBBCCCCCCDDDDDDEEEEE";
+        Map<Character, String> codes = ShannonFano.generateCodes(text);
+
+        assertEquals(5, codes.size());
+        assertEquals("00", codes.get('A'));
+        assertEquals("01", codes.get('B'));
+        assertEquals("10", codes.get('C'));
+        assertEquals("110", codes.get('D'));
+        assertEquals("111", codes.get('E'));
+    }
+
+    @Test
+    void testEdgeCases() {
+        // Test with an empty string
+        assertTrue(ShannonFano.generateCodes("").isEmpty());
+
+        // Test with a single character
+        Map<Character, String> singleCharCodes = ShannonFano.generateCodes("AAAAA");
+        assertEquals(1, singleCharCodes.size());
+        assertEquals("0", singleCharCodes.get('A')); // A single symbol gets code "0"
+
+        // Test with all unique characters
+        String uniqueCharsText = "ABCDEF";
+        Map<Character, String> uniqueCharCodes = ShannonFano.generateCodes(uniqueCharsText);
+        assertEquals(6, uniqueCharCodes.size());
+        // Check that codes are unique and have varying lengths as expected
+        assertEquals(6, uniqueCharCodes.values().stream().distinct().count());
+    }
+
+    @Test
+    void testStringWithTwoChars() {
+        String text = "ABABAB";
+        Map<Character, String> codes = ShannonFano.generateCodes(text);
+
+        assertEquals(2, codes.size());
+        assertTrue(codes.get('A').equals("0") && codes.get('B').equals("1") || codes.get('A').equals("1") && codes.get('B').equals("0"));
+    }
+}

From 219cc33588b1264028bf4f70be059baba6ae1507 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 15 Oct 2025 14:12:16 +0530
Subject: [PATCH 1023/1338] =?UTF-8?q?refactor:=20Enhance=20docs,=20code,?=
 =?UTF-8?q?=20add=20tests=20in=20`LinearDiophantineEquation=E2=80=A6=20(#6?=
 =?UTF-8?q?744)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

refactor: Enhance docs, code, add tests in `LinearDiophantineEquationsSolver`
---
 .../LinearDiophantineEquationsSolver.java     | 157 ++++++++-
 .../LinearDiophantineEquationsSolverTest.java | 330 ++++++++++++++++++
 2 files changed, 486 insertions(+), 1 deletion(-)
 create mode 100644 src/test/java/com/thealgorithms/maths/LinearDiophantineEquationsSolverTest.java

diff --git a/src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java b/src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java
index a50cfb218283..a95e7053e210 100644
--- a/src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java
+++ b/src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java
@@ -2,20 +2,77 @@
 
 import java.util.Objects;
 
+/**
+ * A solver for linear Diophantine equations of the form ax + by = c.
+ * <p>
+ * A linear Diophantine equation is an equation in which only integer solutions
+ * are allowed.
+ * This solver uses the Extended Euclidean Algorithm to find integer solutions
+ * (x, y)
+ * for equations of the form ax + by = c, where a, b, and c are integers.
+ * </p>
+ * <p>
+ * The equation has solutions if and only if gcd(a, b) divides c.
+ * If solutions exist, this solver finds one particular solution.
+ * </p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Diophantine_equation">Diophantine
+ *      Equation</a>
+ * @see <a href=
+ *      "https://en.wikipedia.org/wiki/Extended_Euclidean_algorithm">Extended
+ *      Euclidean Algorithm</a>
+ */
 public final class LinearDiophantineEquationsSolver {
     private LinearDiophantineEquationsSolver() {
     }
 
+    /**
+     * Demonstrates the solver with a sample equation: 3x + 4y = 7.
+     *
+     * @param args command line arguments (not used)
+     */
     public static void main(String[] args) {
         // 3x + 4y = 7
         final var toSolve = new Equation(3, 4, 7);
         System.out.println(findAnySolution(toSolve));
     }
 
+    /**
+     * Finds any integer solution to the linear Diophantine equation ax + by = c.
+     * <p>
+     * The method returns one of three types of solutions:
+     * <ul>
+     * <li>A specific solution (x, y) if solutions exist</li>
+     * <li>{@link Solution#NO_SOLUTION} if no integer solutions exist</li>
+     * <li>{@link Solution#INFINITE_SOLUTIONS} if the equation is 0x + 0y = 0</li>
+     * </ul>
+     * </p>
+     *
+     * @param equation the linear Diophantine equation to solve
+     * @return a Solution object containing the result
+     * @throws NullPointerException if equation is null
+     */
     public static Solution findAnySolution(final Equation equation) {
         if (equation.a() == 0 && equation.b() == 0 && equation.c() == 0) {
             return Solution.INFINITE_SOLUTIONS;
         }
+        if (equation.a() == 0 && equation.b() == 0) {
+            return Solution.NO_SOLUTION;
+        }
+        if (equation.a() == 0) {
+            if (equation.c() % equation.b() == 0) {
+                return new Solution(0, equation.c() / equation.b());
+            } else {
+                return Solution.NO_SOLUTION;
+            }
+        }
+        if (equation.b() == 0) {
+            if (equation.c() % equation.a() == 0) {
+                return new Solution(equation.c() / equation.a(), 0);
+            } else {
+                return Solution.NO_SOLUTION;
+            }
+        }
         final var stub = new GcdSolutionWrapper(0, new Solution(0, 0));
         final var gcdSolution = gcd(equation.a(), equation.b(), stub);
         if (equation.c() % gcdSolution.getGcd() != 0) {
@@ -29,43 +86,100 @@ public static Solution findAnySolution(final Equation equation) {
         return toReturn;
     }
 
+    /**
+     * Computes the GCD of two integers using the Extended Euclidean Algorithm.
+     * <p>
+     * This method also finds coefficients x and y such that ax + by = gcd(a, b).
+     * The coefficients are stored in the 'previous' wrapper object.
+     * </p>
+     *
+     * @param a        the first integer
+     * @param b        the second integer
+     * @param previous a wrapper to store the solution coefficients
+     * @return a GcdSolutionWrapper containing the GCD and coefficients
+     */
     private static GcdSolutionWrapper gcd(final int a, final int b, final GcdSolutionWrapper previous) {
         if (b == 0) {
             return new GcdSolutionWrapper(a, new Solution(1, 0));
         }
         // stub wrapper becomes the `previous` of the next recursive call
         final var stubWrapper = new GcdSolutionWrapper(0, new Solution(0, 0));
-        final var next = /* recursive call */ gcd(b, a % b, stubWrapper);
+        final var next = gcd(b, a % b, stubWrapper);
         previous.getSolution().setX(next.getSolution().getY());
         previous.getSolution().setY(next.getSolution().getX() - (a / b) * (next.getSolution().getY()));
         previous.setGcd(next.getGcd());
         return new GcdSolutionWrapper(next.getGcd(), previous.getSolution());
     }
 
+    /**
+     * Represents a solution (x, y) to a linear Diophantine equation.
+     * <p>
+     * Special instances:
+     * <ul>
+     * <li>{@link #NO_SOLUTION} - indicates no integer solutions exist</li>
+     * <li>{@link #INFINITE_SOLUTIONS} - indicates infinitely many solutions
+     * exist</li>
+     * </ul>
+     * </p>
+     */
     public static final class Solution {
 
+        /**
+         * Singleton instance representing the case where no solution exists.
+         */
         public static final Solution NO_SOLUTION = new Solution(Integer.MAX_VALUE, Integer.MAX_VALUE);
+
+        /**
+         * Singleton instance representing the case where infinite solutions exist.
+         */
         public static final Solution INFINITE_SOLUTIONS = new Solution(Integer.MIN_VALUE, Integer.MIN_VALUE);
+
         private int x;
         private int y;
 
+        /**
+         * Constructs a solution with the given x and y values.
+         *
+         * @param x the x coordinate of the solution
+         * @param y the y coordinate of the solution
+         */
         public Solution(int x, int y) {
             this.x = x;
             this.y = y;
         }
 
+        /**
+         * Gets the x value of this solution.
+         *
+         * @return the x value
+         */
         public int getX() {
             return x;
         }
 
+        /**
+         * Gets the y value of this solution.
+         *
+         * @return the y value
+         */
         public int getY() {
             return y;
         }
 
+        /**
+         * Sets the x value of this solution.
+         *
+         * @param x the new x value
+         */
         public void setX(int x) {
             this.x = x;
         }
 
+        /**
+         * Sets the y value of this solution.
+         *
+         * @param y the new y value
+         */
         public void setY(int y) {
             this.y = y;
         }
@@ -95,14 +209,35 @@ public String toString() {
         }
     }
 
+    /**
+     * Represents a linear Diophantine equation of the form ax + by = c.
+     *
+     * @param a the coefficient of x
+     * @param b the coefficient of y
+     * @param c the constant term
+     */
     public record Equation(int a, int b, int c) {
     }
 
+    /**
+     * A wrapper class that holds both the GCD and the solution coefficients
+     * from the Extended Euclidean Algorithm.
+     * <p>
+     * This class is used internally to pass results between recursive calls
+     * of the GCD computation.
+     * </p>
+     */
     public static final class GcdSolutionWrapper {
 
         private int gcd;
         private Solution solution;
 
+        /**
+         * Constructs a GcdSolutionWrapper with the given GCD and solution.
+         *
+         * @param gcd      the greatest common divisor
+         * @param solution the solution coefficients
+         */
         public GcdSolutionWrapper(int gcd, Solution solution) {
             this.gcd = gcd;
             this.solution = solution;
@@ -120,18 +255,38 @@ public boolean equals(Object obj) {
             return (this.gcd == that.gcd && Objects.equals(this.solution, that.solution));
         }
 
+        /**
+         * Gets the GCD value.
+         *
+         * @return the GCD
+         */
         public int getGcd() {
             return gcd;
         }
 
+        /**
+         * Sets the GCD value.
+         *
+         * @param gcd the new GCD value
+         */
         public void setGcd(int gcd) {
             this.gcd = gcd;
         }
 
+        /**
+         * Gets the solution coefficients.
+         *
+         * @return the solution
+         */
         public Solution getSolution() {
             return solution;
         }
 
+        /**
+         * Sets the solution coefficients.
+         *
+         * @param solution the new solution
+         */
         public void setSolution(Solution solution) {
             this.solution = solution;
         }
diff --git a/src/test/java/com/thealgorithms/maths/LinearDiophantineEquationsSolverTest.java b/src/test/java/com/thealgorithms/maths/LinearDiophantineEquationsSolverTest.java
new file mode 100644
index 000000000000..c4205985dbfd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/LinearDiophantineEquationsSolverTest.java
@@ -0,0 +1,330 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for LinearDiophantineEquationsSolver.
+ * Tests various cases including:
+ * - Equations with solutions
+ * - Equations with no solutions
+ * - Special cases (zero coefficients, infinite solutions)
+ * - Edge cases (negative coefficients, large numbers)
+ */
+class LinearDiophantineEquationsSolverTest {
+
+    /**
+     * Tests the example equation 3x + 4y = 7.
+     * Expected solution: x = -9, y = 8 (or other valid solutions).
+     */
+    @Test
+    void testBasicEquation() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(3, 4, 7);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        // Verify that the solution satisfies the equation
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+
+    /**
+     * Tests an equation with no solution: 2x + 4y = 5.
+     * Since gcd(2, 4) = 2 and 2 does not divide 5, no solution exists.
+     */
+    @Test
+    void testNoSolution() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(2, 4, 5);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertEquals(LinearDiophantineEquationsSolver.Solution.NO_SOLUTION, solution);
+    }
+
+    /**
+     * Tests the trivial equation 0x + 0y = 0.
+     * This has infinite solutions.
+     */
+    @Test
+    void testInfiniteSolutions() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(0, 0, 0);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertEquals(LinearDiophantineEquationsSolver.Solution.INFINITE_SOLUTIONS, solution);
+    }
+
+    /**
+     * Tests an equation where a = 0: 0x + 5y = 10.
+     * Expected solution: x = 0, y = 2.
+     */
+    @Test
+    void testZeroCoefficient() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(0, 5, 10);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+
+    /**
+     * Tests an equation where b = 0: 3x + 0y = 9.
+     * Expected solution: x = 3, y can be anything (solver will return y = 0).
+     */
+    @Test
+    void testZeroCoefficientB() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(3, 0, 9);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+
+    /**
+     * Tests an equation with negative coefficients: -3x + 4y = 7.
+     */
+    @Test
+    void testNegativeCoefficients() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(-3, 4, 7);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+
+    /**
+     * Tests an equation with negative result: 3x + 4y = -7.
+     */
+    @Test
+    void testNegativeResult() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(3, 4, -7);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+
+    /**
+     * Tests an equation with coprime coefficients: 7x + 11y = 1.
+     * Since gcd(7, 11) = 1, a solution exists.
+     */
+    @Test
+    void testCoprimeCoefficients() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(7, 11, 1);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+
+    /**
+     * Tests an equation with larger coefficients: 12x + 18y = 30.
+     * Since gcd(12, 18) = 6 and 6 divides 30, a solution exists.
+     */
+    @Test
+    void testLargerCoefficients() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(12, 18, 30);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+
+    /**
+     * Tests an equation that has no solution due to GCD: 6x + 9y = 5.
+     * Since gcd(6, 9) = 3 and 3 does not divide 5, no solution exists.
+     */
+    @Test
+    void testNoSolutionGcdCheck() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(6, 9, 5);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertEquals(LinearDiophantineEquationsSolver.Solution.NO_SOLUTION, solution);
+    }
+
+    /**
+     * Tests the equation x + y = 1.
+     * Simple case where gcd(1, 1) = 1.
+     */
+    @Test
+    void testSimpleCase() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(1, 1, 1);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+
+    /**
+     * Tests Solution equality.
+     */
+    @Test
+    void testSolutionEquality() {
+        final var solution1 = new LinearDiophantineEquationsSolver.Solution(3, 5);
+        final var solution2 = new LinearDiophantineEquationsSolver.Solution(3, 5);
+        final var solution3 = new LinearDiophantineEquationsSolver.Solution(3, 6);
+
+        assertEquals(solution1, solution2);
+        assertNotEquals(solution3, solution1);
+        assertEquals(solution1, solution1);
+        assertNotEquals(null, solution1);
+        assertNotEquals("string", solution1);
+    }
+
+    /**
+     * Tests Solution hashCode.
+     */
+    @Test
+    void testSolutionHashCode() {
+        final var solution1 = new LinearDiophantineEquationsSolver.Solution(3, 5);
+        final var solution2 = new LinearDiophantineEquationsSolver.Solution(3, 5);
+
+        assertEquals(solution1.hashCode(), solution2.hashCode());
+    }
+
+    /**
+     * Tests Solution toString.
+     */
+    @Test
+    void testSolutionToString() {
+        final var solution = new LinearDiophantineEquationsSolver.Solution(3, 5);
+        final var str = solution.toString();
+
+        assertTrue(str.contains("3"));
+        assertTrue(str.contains("5"));
+        assertTrue(str.contains("Solution"));
+    }
+
+    /**
+     * Tests GcdSolutionWrapper equality.
+     */
+    @Test
+    void testGcdSolutionWrapperEquality() {
+        final var solution = new LinearDiophantineEquationsSolver.Solution(1, 2);
+        final var wrapper1 = new LinearDiophantineEquationsSolver.GcdSolutionWrapper(5, solution);
+        final var wrapper2 = new LinearDiophantineEquationsSolver.GcdSolutionWrapper(5, solution);
+        final var wrapper3 = new LinearDiophantineEquationsSolver.GcdSolutionWrapper(6, solution);
+
+        assertEquals(wrapper1, wrapper2);
+        assertNotEquals(wrapper3, wrapper1);
+        assertEquals(wrapper1, wrapper1);
+        assertNotEquals(null, wrapper1);
+        assertNotEquals("string", wrapper1);
+    }
+
+    /**
+     * Tests GcdSolutionWrapper hashCode.
+     */
+    @Test
+    void testGcdSolutionWrapperHashCode() {
+        final var solution = new LinearDiophantineEquationsSolver.Solution(1, 2);
+        final var wrapper1 = new LinearDiophantineEquationsSolver.GcdSolutionWrapper(5, solution);
+        final var wrapper2 = new LinearDiophantineEquationsSolver.GcdSolutionWrapper(5, solution);
+
+        assertEquals(wrapper1.hashCode(), wrapper2.hashCode());
+    }
+
+    /**
+     * Tests GcdSolutionWrapper toString.
+     */
+    @Test
+    void testGcdSolutionWrapperToString() {
+        final var solution = new LinearDiophantineEquationsSolver.Solution(1, 2);
+        final var wrapper = new LinearDiophantineEquationsSolver.GcdSolutionWrapper(5, solution);
+        final var str = wrapper.toString();
+
+        assertTrue(str.contains("5"));
+        assertTrue(str.contains("GcdSolutionWrapper"));
+    }
+
+    /**
+     * Tests Equation record functionality.
+     */
+    @Test
+    void testEquationRecord() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(3, 4, 7);
+
+        assertEquals(3, equation.a());
+        assertEquals(4, equation.b());
+        assertEquals(7, equation.c());
+    }
+
+    /**
+     * Tests an equation with c = 0: 3x + 4y = 0.
+     * Expected solution: x = 0, y = 0.
+     */
+    @Test
+    void testZeroResult() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(3, 4, 0);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+
+    /**
+     * Tests Solution setters.
+     */
+    @Test
+    void testSolutionSetters() {
+        final var solution = new LinearDiophantineEquationsSolver.Solution(1, 2);
+
+        solution.setX(10);
+        solution.setY(20);
+
+        assertEquals(10, solution.getX());
+        assertEquals(20, solution.getY());
+    }
+
+    /**
+     * Tests GcdSolutionWrapper setters.
+     */
+    @Test
+    void testGcdSolutionWrapperSetters() {
+        final var solution = new LinearDiophantineEquationsSolver.Solution(1, 2);
+        final var wrapper = new LinearDiophantineEquationsSolver.GcdSolutionWrapper(5, solution);
+
+        final var newSolution = new LinearDiophantineEquationsSolver.Solution(3, 4);
+        wrapper.setGcd(10);
+        wrapper.setSolution(newSolution);
+
+        assertEquals(10, wrapper.getGcd());
+        assertEquals(newSolution, wrapper.getSolution());
+    }
+
+    /**
+     * Tests an equation with both coefficients negative: -3x - 4y = -7.
+     */
+    @Test
+    void testBothCoefficientsNegative() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(-3, -4, -7);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+
+    /**
+     * Tests an equation with large prime coefficients: 97x + 101y = 198.
+     */
+    @Test
+    void testLargePrimeCoefficients() {
+        final var equation = new LinearDiophantineEquationsSolver.Equation(97, 101, 198);
+        final var solution = LinearDiophantineEquationsSolver.findAnySolution(equation);
+
+        assertNotNull(solution);
+        int result = equation.a() * solution.getX() + equation.b() * solution.getY();
+        assertEquals(equation.c(), result);
+    }
+}

From d62b438fcd57c4ef5b8e5dec45f975387f846a64 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 15 Oct 2025 14:16:17 +0530
Subject: [PATCH 1024/1338] refactor: Enhance docs, code, add tests in
 `HarshadNumber` (#6745)

---
 .../thealgorithms/maths/HarshadNumber.java    |  61 ++++++--
 .../maths/HarshadNumberTest.java              | 140 ++++++++++++++++--
 2 files changed, 170 insertions(+), 31 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/HarshadNumber.java b/src/main/java/com/thealgorithms/maths/HarshadNumber.java
index 5792e925a8aa..abe21cb045ae 100644
--- a/src/main/java/com/thealgorithms/maths/HarshadNumber.java
+++ b/src/main/java/com/thealgorithms/maths/HarshadNumber.java
@@ -1,49 +1,78 @@
 package com.thealgorithms.maths;
 
-// Wikipedia for Harshad Number : https://en.wikipedia.org/wiki/Harshad_number
-
+/**
+ * A Harshad number (or Niven number) in a given number base is an integer that
+ * is divisible by the sum of its digits.
+ * For example, 18 is a Harshad number because 18 is divisible by (1 + 8) = 9.
+ * The name "Harshad" comes from the Sanskrit words "harṣa" (joy) and "da"
+ * (give), meaning "joy-giver".
+ *
+ * @author <a href="https://github.com/Hardvan">Hardvan</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Harshad_number">Harshad Number -
+ *      Wikipedia</a>
+ */
 public final class HarshadNumber {
     private HarshadNumber() {
     }
 
     /**
-     * A function to check if a number is Harshad number or not
+     * Checks if a number is a Harshad number.
+     * A Harshad number is a positive integer that is divisible by the sum of its
+     * digits.
      *
-     * @param n The number to be checked
-     * @return {@code true} if {@code a} is Harshad number, otherwise
+     * @param n the number to be checked (must be positive)
+     * @return {@code true} if {@code n} is a Harshad number, otherwise
      *         {@code false}
+     * @throws IllegalArgumentException if {@code n} is less than or equal to 0
      */
     public static boolean isHarshad(long n) {
         if (n <= 0) {
-            return false;
+            throw new IllegalArgumentException("Input must be a positive integer. Received: " + n);
         }
 
-        long t = n;
+        long temp = n;
         long sumOfDigits = 0;
-        while (t > 0) {
-            sumOfDigits += t % 10;
-            t /= 10;
+        while (temp > 0) {
+            sumOfDigits += temp % 10;
+            temp /= 10;
         }
 
         return n % sumOfDigits == 0;
     }
 
     /**
-     * A function to check if a number is Harshad number or not
+     * Checks if a number represented as a string is a Harshad number.
+     * A Harshad number is a positive integer that is divisible by the sum of its
+     * digits.
      *
-     * @param s The number in String to be checked
-     * @return {@code true} if {@code a} is Harshad number, otherwise
+     * @param s the string representation of the number to be checked
+     * @return {@code true} if the number is a Harshad number, otherwise
      *         {@code false}
+     * @throws IllegalArgumentException if {@code s} is null, empty, or represents a
+     *                                  non-positive integer
+     * @throws NumberFormatException    if {@code s} cannot be parsed as a long
      */
     public static boolean isHarshad(String s) {
-        final Long n = Long.valueOf(s);
+        if (s == null || s.isEmpty()) {
+            throw new IllegalArgumentException("Input string cannot be null or empty");
+        }
+
+        final long n;
+        try {
+            n = Long.parseLong(s);
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException("Input string must be a valid integer: " + s, e);
+        }
+
         if (n <= 0) {
-            return false;
+            throw new IllegalArgumentException("Input must be a positive integer. Received: " + n);
         }
 
         int sumOfDigits = 0;
         for (char ch : s.toCharArray()) {
-            sumOfDigits += ch - '0';
+            if (Character.isDigit(ch)) {
+                sumOfDigits += ch - '0';
+            }
         }
 
         return n % sumOfDigits == 0;
diff --git a/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java b/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java
index af1c459f3d7f..299e6bd78a99 100644
--- a/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/HarshadNumberTest.java
@@ -1,25 +1,135 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
-public class HarshadNumberTest {
+/**
+ * Test class for {@link HarshadNumber}.
+ * Tests various scenarios including positive cases, edge cases, and exception
+ * handling.
+ */
+class HarshadNumberTest {
+
+    @Test
+    void testValidHarshadNumbers() {
+        // Single digit Harshad numbers (all single digits except 0 are Harshad numbers)
+        Assertions.assertTrue(HarshadNumber.isHarshad(1));
+        Assertions.assertTrue(HarshadNumber.isHarshad(2));
+        Assertions.assertTrue(HarshadNumber.isHarshad(3));
+        Assertions.assertTrue(HarshadNumber.isHarshad(4));
+        Assertions.assertTrue(HarshadNumber.isHarshad(5));
+        Assertions.assertTrue(HarshadNumber.isHarshad(6));
+        Assertions.assertTrue(HarshadNumber.isHarshad(7));
+        Assertions.assertTrue(HarshadNumber.isHarshad(8));
+        Assertions.assertTrue(HarshadNumber.isHarshad(9));
+
+        // Two digit Harshad numbers
+        Assertions.assertTrue(HarshadNumber.isHarshad(10)); // 10 / (1 + 0) = 10
+        Assertions.assertTrue(HarshadNumber.isHarshad(12)); // 12 / (1 + 2) = 4
+        Assertions.assertTrue(HarshadNumber.isHarshad(18)); // 18 / (1 + 8) = 2
+        Assertions.assertTrue(HarshadNumber.isHarshad(20)); // 20 / (2 + 0) = 10
+        Assertions.assertTrue(HarshadNumber.isHarshad(21)); // 21 / (2 + 1) = 7
+
+        // Three digit Harshad numbers
+        Assertions.assertTrue(HarshadNumber.isHarshad(100)); // 100 / (1 + 0 + 0) = 100
+        Assertions.assertTrue(HarshadNumber.isHarshad(102)); // 102 / (1 + 0 + 2) = 34
+        Assertions.assertTrue(HarshadNumber.isHarshad(108)); // 108 / (1 + 0 + 8) = 12
+
+        // Large Harshad numbers
+        Assertions.assertTrue(HarshadNumber.isHarshad(1000)); // 1000 / (1 + 0 + 0 + 0) = 1000
+        Assertions.assertTrue(HarshadNumber.isHarshad(1002)); // 1002 / (1 + 0 + 0 + 2) = 334
+        Assertions.assertTrue(HarshadNumber.isHarshad(999999999)); // 999999999 / (9*9) = 12345679
+    }
 
     @Test
-    public void harshadNumber() {
+    void testInvalidHarshadNumbers() {
+        // Numbers that are not Harshad numbers
+        Assertions.assertFalse(HarshadNumber.isHarshad(11)); // 11 / (1 + 1) = 5.5
+        Assertions.assertFalse(HarshadNumber.isHarshad(13)); // 13 / (1 + 3) = 3.25
+        Assertions.assertFalse(HarshadNumber.isHarshad(17)); // 17 / (1 + 7) = 2.125
+        Assertions.assertFalse(HarshadNumber.isHarshad(19)); // 19 / (1 + 9) = 1.9
+        Assertions.assertFalse(HarshadNumber.isHarshad(23)); // 23 / (2 + 3) = 4.6
+        Assertions.assertFalse(HarshadNumber.isHarshad(101)); // 101 / (1 + 0 + 1) = 50.5
+    }
 
-        assertTrue(HarshadNumber.isHarshad(18));
-        assertFalse(HarshadNumber.isHarshad(-18));
-        assertFalse(HarshadNumber.isHarshad(19));
-        assertTrue(HarshadNumber.isHarshad(999999999));
-        assertFalse(HarshadNumber.isHarshad(0));
+    @Test
+    void testZeroThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad(0));
+    }
 
-        assertTrue(HarshadNumber.isHarshad("18"));
-        assertFalse(HarshadNumber.isHarshad("-18"));
-        assertFalse(HarshadNumber.isHarshad("19"));
-        assertTrue(HarshadNumber.isHarshad("999999999"));
-        assertTrue(HarshadNumber.isHarshad("99999999999100"));
+    @Test
+    void testNegativeNumbersThrowException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad(-1));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad(-18));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad(-100));
+    }
+
+    @Test
+    void testValidHarshadNumbersWithString() {
+        // Single digit Harshad numbers
+        Assertions.assertTrue(HarshadNumber.isHarshad("1"));
+        Assertions.assertTrue(HarshadNumber.isHarshad("2"));
+        Assertions.assertTrue(HarshadNumber.isHarshad("9"));
+
+        // Two digit Harshad numbers
+        Assertions.assertTrue(HarshadNumber.isHarshad("10"));
+        Assertions.assertTrue(HarshadNumber.isHarshad("12"));
+        Assertions.assertTrue(HarshadNumber.isHarshad("18"));
+
+        // Large Harshad numbers
+        Assertions.assertTrue(HarshadNumber.isHarshad("1000"));
+        Assertions.assertTrue(HarshadNumber.isHarshad("999999999"));
+        Assertions.assertTrue(HarshadNumber.isHarshad("99999999999100"));
+    }
+
+    @Test
+    void testInvalidHarshadNumbersWithString() {
+        // Numbers that are not Harshad numbers
+        Assertions.assertFalse(HarshadNumber.isHarshad("11"));
+        Assertions.assertFalse(HarshadNumber.isHarshad("13"));
+        Assertions.assertFalse(HarshadNumber.isHarshad("19"));
+        Assertions.assertFalse(HarshadNumber.isHarshad("23"));
+    }
+
+    @Test
+    void testStringWithZeroThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad("0"));
+    }
+
+    @Test
+    void testStringWithNegativeNumbersThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad("-1"));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad("-18"));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad("-100"));
+    }
+
+    @Test
+    void testNullStringThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad(null));
+    }
+
+    @Test
+    void testEmptyStringThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad(""));
+    }
+
+    @Test
+    void testInvalidStringThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad("abc"));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad("12.5"));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad("12a"));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> HarshadNumber.isHarshad(" 12 "));
+    }
+
+    @Test
+    void testMaxLongValue() {
+        // Test with a large number close to Long.MAX_VALUE
+        long largeHarshadCandidate = 9223372036854775800L;
+        // This specific number may or may not be Harshad, just testing it doesn't crash
+        try {
+            HarshadNumber.isHarshad(largeHarshadCandidate);
+        } catch (Exception e) {
+            Assertions.fail("Should not throw exception for valid large numbers");
+        }
     }
 }

From f460c601d3dcf7b572b381e38715bb657e1b4aad Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 15 Oct 2025 14:26:57 +0530
Subject: [PATCH 1025/1338] refactor: Enhance docs, code, add tests in
 `HeronsFormula` (#6746)

* refactor: Enhance docs, code, add tests in `HeronsFormula`

* Fix lint
---
 .../thealgorithms/maths/HeronsFormula.java    |  65 +++++++--
 .../maths/HeronsFormulaTest.java              | 128 ++++++++++++++++--
 2 files changed, 170 insertions(+), 23 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/HeronsFormula.java b/src/main/java/com/thealgorithms/maths/HeronsFormula.java
index 5baee715d1ec..10438e2888b9 100644
--- a/src/main/java/com/thealgorithms/maths/HeronsFormula.java
+++ b/src/main/java/com/thealgorithms/maths/HeronsFormula.java
@@ -1,33 +1,76 @@
 package com.thealgorithms.maths;
 
 /**
- * Wikipedia for HeronsFormula => https://en.wikipedia.org/wiki/Heron%27s_formula
- * Find the area of a triangle using only side lengths
+ * Heron's Formula implementation for calculating the area of a triangle given
+ * its three side lengths.
+ * <p>
+ * Heron's Formula states that the area of a triangle whose sides have lengths
+ * a, b, and c is:
+ * Area = √(s(s - a)(s - b)(s - c))
+ * where s is the semi-perimeter of the triangle: s = (a + b + c) / 2
+ * </p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Heron%27s_formula">Heron's
+ *      Formula - Wikipedia</a>
+ * @author satyabarghav
  */
-
 public final class HeronsFormula {
 
-    /*
-     * A function to get the Area of a Triangle using Heron's Formula
-     * @param s1,s2,s3 => the three sides of the Triangle
-     * @return area using the formula (√(s(s – s1)(s – s2)(s – s3)))
-     * here s is called semi-perimeter and it is the half of the perimeter (i.e; s = (s1+s2+s3)/2)
-     * @author satyabarghav
+    /**
+     * Private constructor to prevent instantiation of this utility class.
      */
     private HeronsFormula() {
     }
 
+    /**
+     * Checks if all three side lengths are positive.
+     *
+     * @param a the length of the first side
+     * @param b the length of the second side
+     * @param c the length of the third side
+     * @return true if all sides are positive, false otherwise
+     */
     private static boolean areAllSidesPositive(final double a, final double b, final double c) {
         return a > 0 && b > 0 && c > 0;
     }
 
+    /**
+     * Checks if the given side lengths satisfy the triangle inequality theorem.
+     * <p>
+     * The triangle inequality theorem states that the sum of any two sides
+     * of a triangle must be greater than the third side.
+     * </p>
+     *
+     * @param a the length of the first side
+     * @param b the length of the second side
+     * @param c the length of the third side
+     * @return true if the sides can form a valid triangle, false otherwise
+     */
     private static boolean canFormTriangle(final double a, final double b, final double c) {
         return a + b > c && b + c > a && c + a > b;
     }
 
+    /**
+     * Calculates the area of a triangle using Heron's Formula.
+     * <p>
+     * Given three side lengths a, b, and c, the area is computed as:
+     * Area = √(s(s - a)(s - b)(s - c))
+     * where s is the semi-perimeter: s = (a + b + c) / 2
+     * </p>
+     *
+     * @param a the length of the first side (must be positive)
+     * @param b the length of the second side (must be positive)
+     * @param c the length of the third side (must be positive)
+     * @return the area of the triangle
+     * @throws IllegalArgumentException if any side length is non-positive or if the
+     *                                  sides cannot form a valid triangle
+     */
     public static double herons(final double a, final double b, final double c) {
-        if (!areAllSidesPositive(a, b, c) || !canFormTriangle(a, b, c)) {
-            throw new IllegalArgumentException("Triangle can't be formed with the given side lengths");
+        if (!areAllSidesPositive(a, b, c)) {
+            throw new IllegalArgumentException("All side lengths must be positive");
+        }
+        if (!canFormTriangle(a, b, c)) {
+            throw new IllegalArgumentException("Triangle cannot be formed with the given side lengths (violates triangle inequality)");
         }
         final double s = (a + b + c) / 2.0;
         return Math.sqrt((s) * (s - a) * (s - b) * (s - c));
diff --git a/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java b/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java
index 22cecf4dc960..5175c6348c9f 100644
--- a/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java
+++ b/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java
@@ -3,37 +3,141 @@
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
-public class HeronsFormulaTest {
+/**
+ * Test cases for {@link HeronsFormula}.
+ */
+class HeronsFormulaTest {
+
+    private static final double EPSILON = 1e-10;
+
+    @Test
+    void testRightTriangleThreeFourFive() {
+        Assertions.assertEquals(6.0, HeronsFormula.herons(3, 4, 5), EPSILON);
+    }
+
+    @Test
+    void testTriangleTwentyFourThirtyEighteen() {
+        Assertions.assertEquals(216.0, HeronsFormula.herons(24, 30, 18), EPSILON);
+    }
+
+    @Test
+    void testEquilateralTriangle() {
+        Assertions.assertEquals(0.4330127018922193, HeronsFormula.herons(1, 1, 1), EPSILON);
+    }
+
+    @Test
+    void testScaleneTriangleFourFiveEight() {
+        Assertions.assertEquals(8.181534085976786, HeronsFormula.herons(4, 5, 8), EPSILON);
+    }
+
+    @Test
+    void testEquilateralTriangleLargeSides() {
+        final double side = 10.0;
+        final double expectedArea = Math.sqrt(3) / 4 * side * side;
+        Assertions.assertEquals(expectedArea, HeronsFormula.herons(side, side, side), EPSILON);
+    }
 
     @Test
-    void test1() {
-        Assertions.assertEquals(HeronsFormula.herons(3, 4, 5), 6.0);
+    void testIsoscelesTriangle() {
+        Assertions.assertEquals(12.0, HeronsFormula.herons(5, 5, 6), EPSILON);
     }
 
     @Test
-    void test2() {
-        Assertions.assertEquals(HeronsFormula.herons(24, 30, 18), 216.0);
+    void testSmallTriangle() {
+        Assertions.assertEquals(0.4330127018922193, HeronsFormula.herons(1.0, 1.0, 1.0), EPSILON);
     }
 
     @Test
-    void test3() {
-        Assertions.assertEquals(HeronsFormula.herons(1, 1, 1), 0.4330127018922193);
+    void testLargeTriangle() {
+        Assertions.assertEquals(600.0, HeronsFormula.herons(30, 40, 50), EPSILON);
     }
 
     @Test
-    void test4() {
-        Assertions.assertEquals(HeronsFormula.herons(4, 5, 8), 8.181534085976786);
+    void testDecimalSides() {
+        final double area = HeronsFormula.herons(2.5, 3.5, 4.0);
+        Assertions.assertTrue(area > 0);
+        Assertions.assertEquals(4.330127018922194, area, EPSILON);
     }
 
     @Test
-    public void testCalculateAreaWithInvalidInput() {
+    void testDegenerateTriangleEqualToSumOfOtherTwo() {
         Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 2, 3); });
+    }
+
+    @Test
+    void testDegenerateTriangleVariant2() {
         Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(2, 1, 3); });
+    }
+
+    @Test
+    void testDegenerateTriangleVariant3() {
         Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(3, 2, 1); });
+    }
+
+    @Test
+    void testDegenerateTriangleVariant4() {
         Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 3, 2); });
+    }
 
-        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 1, 0); });
-        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 0, 1); });
+    @Test
+    void testInvalidTriangleSideGreaterThanSum() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 1, 5); });
+    }
+
+    @Test
+    void testZeroFirstSide() {
         Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(0, 1, 1); });
     }
+
+    @Test
+    void testZeroSecondSide() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 0, 1); });
+    }
+
+    @Test
+    void testZeroThirdSide() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(1, 1, 0); });
+    }
+
+    @Test
+    void testNegativeFirstSide() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(-1, 2, 2); });
+    }
+
+    @Test
+    void testNegativeSecondSide() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(2, -1, 2); });
+    }
+
+    @Test
+    void testNegativeThirdSide() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(2, 2, -1); });
+    }
+
+    @Test
+    void testAllNegativeSides() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(-1, -2, -3); });
+    }
+
+    @Test
+    void testAllZeroSides() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { HeronsFormula.herons(0, 0, 0); });
+    }
+
+    @Test
+    void testVerySmallTriangle() {
+        final double result = HeronsFormula.herons(0.001, 0.001, 0.001);
+        Assertions.assertTrue(result > 0);
+        Assertions.assertTrue(result < 0.001);
+    }
+
+    @Test
+    void testRightTriangleFiveTwelveThirteen() {
+        Assertions.assertEquals(30.0, HeronsFormula.herons(5, 12, 13), EPSILON);
+    }
+
+    @Test
+    void testRightTriangleEightFifteenSeventeen() {
+        Assertions.assertEquals(60.0, HeronsFormula.herons(8, 15, 17), EPSILON);
+    }
 }

From c6497a23ec984722ad835ba6ef75bdb7a845ce2a Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 15 Oct 2025 14:37:49 +0530
Subject: [PATCH 1026/1338] refactor: Enhance docs, code, add tests in
 `LucasSeries` (#6749)

---
 .../com/thealgorithms/maths/LucasSeries.java  |  55 +++++--
 .../thealgorithms/maths/LucasSeriesTest.java  | 140 +++++++++++++++++-
 2 files changed, 178 insertions(+), 17 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/LucasSeries.java b/src/main/java/com/thealgorithms/maths/LucasSeries.java
index e277c511f317..90a35f0d6259 100644
--- a/src/main/java/com/thealgorithms/maths/LucasSeries.java
+++ b/src/main/java/com/thealgorithms/maths/LucasSeries.java
@@ -1,38 +1,69 @@
 package com.thealgorithms.maths;
 
 /**
- * https://en.wikipedia.org/wiki/Lucas_number
+ * Utility class for calculating Lucas numbers.
+ * The Lucas sequence is similar to the Fibonacci sequence but starts with 2 and
+ * 1.
+ * The sequence follows: L(n) = L(n-1) + L(n-2)
+ * Starting values: L(1) = 2, L(2) = 1
+ * Sequence: 2, 1, 3, 4, 7, 11, 18, 29, 47, 76, 123, ...
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Lucas_number">Lucas Number</a>
+ * @author TheAlgorithms Contributors
  */
 public final class LucasSeries {
     private LucasSeries() {
     }
 
     /**
-     * Calculate nth number of Lucas Series(2, 1, 3, 4, 7, 11, 18, 29, 47, 76,
-     * 123, ....) using recursion
+     * Calculate the nth Lucas number using recursion.
+     * Time Complexity: O(2^n) - exponential due to recursive calls
+     * Space Complexity: O(n) - recursion depth
      *
-     * @param n nth
-     * @return nth number of Lucas Series
+     * @param n the position in the Lucas sequence (1-indexed, must be positive)
+     * @return the nth Lucas number
+     * @throws IllegalArgumentException if n is less than 1
      */
     public static int lucasSeries(int n) {
-        return n == 1 ? 2 : n == 2 ? 1 : lucasSeries(n - 1) + lucasSeries(n - 2);
+        if (n < 1) {
+            throw new IllegalArgumentException("Input must be a positive integer. Provided: " + n);
+        }
+        if (n == 1) {
+            return 2;
+        }
+        if (n == 2) {
+            return 1;
+        }
+        return lucasSeries(n - 1) + lucasSeries(n - 2);
     }
 
     /**
-     * Calculate nth number of Lucas Series(2, 1, 3, 4, 7, 11, 18, 29, 47, 76,
-     * 123, ....) using iteration
+     * Calculate the nth Lucas number using iteration.
+     * Time Complexity: O(n) - single loop through n iterations
+     * Space Complexity: O(1) - constant space usage
      *
-     * @param n nth
-     * @return nth number of lucas series
+     * @param n the position in the Lucas sequence (1-indexed, must be positive)
+     * @return the nth Lucas number
+     * @throws IllegalArgumentException if n is less than 1
      */
     public static int lucasSeriesIteration(int n) {
+        if (n < 1) {
+            throw new IllegalArgumentException("Input must be a positive integer. Provided: " + n);
+        }
+        if (n == 1) {
+            return 2;
+        }
+        if (n == 2) {
+            return 1;
+        }
+
         int previous = 2;
         int current = 1;
-        for (int i = 1; i < n; i++) {
+        for (int i = 2; i < n; i++) {
             int next = previous + current;
             previous = current;
             current = next;
         }
-        return previous;
+        return current;
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/LucasSeriesTest.java b/src/test/java/com/thealgorithms/maths/LucasSeriesTest.java
index 3576268c5d0c..4b6c1e41ecb6 100644
--- a/src/test/java/com/thealgorithms/maths/LucasSeriesTest.java
+++ b/src/test/java/com/thealgorithms/maths/LucasSeriesTest.java
@@ -1,28 +1,158 @@
 package com.thealgorithms.maths;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
-public class LucasSeriesTest {
+/**
+ * Test cases for {@link LucasSeries} class.
+ * Tests both recursive and iterative implementations for correctness,
+ * edge cases, and error handling.
+ */
+class LucasSeriesTest {
+
+    /**
+     * Test the first Lucas number L(1) = 2
+     */
     @Test
-    void lucasSeriesTwo() {
+    void testFirstLucasNumber() {
         assertEquals(2, LucasSeries.lucasSeries(1));
         assertEquals(2, LucasSeries.lucasSeriesIteration(1));
     }
+
+    /**
+     * Test the second Lucas number L(2) = 1
+     */
     @Test
-    void lucasSeriesOne() {
+    void testSecondLucasNumber() {
         assertEquals(1, LucasSeries.lucasSeries(2));
         assertEquals(1, LucasSeries.lucasSeriesIteration(2));
     }
+
+    /**
+     * Test the third Lucas number L(3) = 3
+     */
+    @Test
+    void testThirdLucasNumber() {
+        assertEquals(3, LucasSeries.lucasSeries(3));
+        assertEquals(3, LucasSeries.lucasSeriesIteration(3));
+    }
+
+    /**
+     * Test the fourth Lucas number L(4) = 4
+     */
     @Test
-    void lucasSeriesSeven() {
+    void testFourthLucasNumber() {
+        assertEquals(4, LucasSeries.lucasSeries(4));
+        assertEquals(4, LucasSeries.lucasSeriesIteration(4));
+    }
+
+    /**
+     * Test the fifth Lucas number L(5) = 7
+     */
+    @Test
+    void testFifthLucasNumber() {
         assertEquals(7, LucasSeries.lucasSeries(5));
         assertEquals(7, LucasSeries.lucasSeriesIteration(5));
     }
+
+    /**
+     * Test the sixth Lucas number L(6) = 11
+     */
+    @Test
+    void testSixthLucasNumber() {
+        assertEquals(11, LucasSeries.lucasSeries(6));
+        assertEquals(11, LucasSeries.lucasSeriesIteration(6));
+    }
+
+    /**
+     * Test the seventh Lucas number L(7) = 18
+     */
+    @Test
+    void testSeventhLucasNumber() {
+        assertEquals(18, LucasSeries.lucasSeries(7));
+        assertEquals(18, LucasSeries.lucasSeriesIteration(7));
+    }
+
+    /**
+     * Test the eighth Lucas number L(8) = 29
+     */
+    @Test
+    void testEighthLucasNumber() {
+        assertEquals(29, LucasSeries.lucasSeries(8));
+        assertEquals(29, LucasSeries.lucasSeriesIteration(8));
+    }
+
+    /**
+     * Test the ninth Lucas number L(9) = 47
+     */
     @Test
-    void lucasSeriesEleven() {
+    void testNinthLucasNumber() {
+        assertEquals(47, LucasSeries.lucasSeries(9));
+        assertEquals(47, LucasSeries.lucasSeriesIteration(9));
+    }
+
+    /**
+     * Test the tenth Lucas number L(10) = 76
+     */
+    @Test
+    void testTenthLucasNumber() {
+        assertEquals(76, LucasSeries.lucasSeries(10));
+        assertEquals(76, LucasSeries.lucasSeriesIteration(10));
+    }
+
+    /**
+     * Test the eleventh Lucas number L(11) = 123
+     */
+    @Test
+    void testEleventhLucasNumber() {
         assertEquals(123, LucasSeries.lucasSeries(11));
         assertEquals(123, LucasSeries.lucasSeriesIteration(11));
     }
+
+    /**
+     * Test larger Lucas numbers to ensure correctness
+     */
+    @Test
+    void testLargerLucasNumbers() {
+        assertEquals(199, LucasSeries.lucasSeries(12));
+        assertEquals(199, LucasSeries.lucasSeriesIteration(12));
+        assertEquals(322, LucasSeries.lucasSeries(13));
+        assertEquals(322, LucasSeries.lucasSeriesIteration(13));
+        assertEquals(521, LucasSeries.lucasSeries(14));
+        assertEquals(521, LucasSeries.lucasSeriesIteration(14));
+        assertEquals(843, LucasSeries.lucasSeries(15));
+        assertEquals(843, LucasSeries.lucasSeriesIteration(15));
+    }
+
+    /**
+     * Test that both methods produce the same results
+     */
+    @Test
+    void testRecursiveAndIterativeConsistency() {
+        for (int i = 1; i <= 15; i++) {
+            assertEquals(LucasSeries.lucasSeries(i), LucasSeries.lucasSeriesIteration(i), "Mismatch at position " + i);
+        }
+    }
+
+    /**
+     * Test invalid input: zero
+     */
+    @Test
+    void testZeroInputThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> LucasSeries.lucasSeries(0));
+        assertThrows(IllegalArgumentException.class, () -> LucasSeries.lucasSeriesIteration(0));
+    }
+
+    /**
+     * Test invalid input: negative number
+     */
+    @Test
+    void testNegativeInputThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> LucasSeries.lucasSeries(-1));
+        assertThrows(IllegalArgumentException.class, () -> LucasSeries.lucasSeriesIteration(-1));
+        assertThrows(IllegalArgumentException.class, () -> LucasSeries.lucasSeries(-5));
+        assertThrows(IllegalArgumentException.class, () -> LucasSeries.lucasSeriesIteration(-5));
+    }
 }

From f8688ba38d2cb2a1661e44e5b4ab8005d2e666f2 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Wed, 15 Oct 2025 14:44:00 +0530
Subject: [PATCH 1027/1338] refactor: Enhance docs, code, add tests in `Means`
 (#6750)

---
 .../java/com/thealgorithms/maths/Means.java   |  97 +++++++--
 .../com/thealgorithms/maths/MeansTest.java    | 199 +++++++++++++++---
 2 files changed, 255 insertions(+), 41 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Means.java b/src/main/java/com/thealgorithms/maths/Means.java
index dccc820b172e..5445a3caebc7 100644
--- a/src/main/java/com/thealgorithms/maths/Means.java
+++ b/src/main/java/com/thealgorithms/maths/Means.java
@@ -4,9 +4,27 @@
 import org.apache.commons.collections4.IterableUtils;
 
 /**
- * https://en.wikipedia.org/wiki/Mean
+ * Utility class for computing various types of statistical means.
  * <p>
- * by: Punit Patel
+ * This class provides static methods to calculate different types of means
+ * (averages)
+ * from a collection of numbers. All methods accept any {@link Iterable}
+ * collection of
+ * {@link Double} values and return the computed mean as a {@link Double}.
+ * </p>
+ *
+ * <p>
+ * Supported means:
+ * <ul>
+ * <li><b>Arithmetic Mean</b>: The sum of all values divided by the count</li>
+ * <li><b>Geometric Mean</b>: The nth root of the product of n values</li>
+ * <li><b>Harmonic Mean</b>: The reciprocal of the arithmetic mean of
+ * reciprocals</li>
+ * </ul>
+ * </p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Mean">Mean (Wikipedia)</a>
+ * @author Punit Patel
  */
 public final class Means {
 
@@ -14,41 +32,90 @@ private Means() {
     }
 
     /**
-     * @brief computes the [Arithmetic Mean](https://en.wikipedia.org/wiki/Arithmetic_mean) of the input
-     * @param numbers the input numbers
-     * @throws IllegalArgumentException empty input
+     * Computes the arithmetic mean (average) of the given numbers.
+     * <p>
+     * The arithmetic mean is calculated as: (x₁ + x₂ + ... + xₙ) / n
+     * </p>
+     * <p>
+     * Example: For numbers [2, 4, 6], the arithmetic mean is (2+4+6)/3 = 4.0
+     * </p>
+     *
+     * @param numbers the input numbers (must not be empty)
      * @return the arithmetic mean of the input numbers
+     * @throws IllegalArgumentException if the input is empty
+     * @see <a href="https://en.wikipedia.org/wiki/Arithmetic_mean">Arithmetic
+     *      Mean</a>
      */
     public static Double arithmetic(final Iterable<Double> numbers) {
         checkIfNotEmpty(numbers);
-        return StreamSupport.stream(numbers.spliterator(), false).reduce((x, y) -> x + y).get() / IterableUtils.size(numbers);
+        double sum = StreamSupport.stream(numbers.spliterator(), false).reduce(0d, (x, y) -> x + y);
+        int size = IterableUtils.size(numbers);
+        return sum / size;
     }
 
     /**
-     * @brief computes the [Geometric Mean](https://en.wikipedia.org/wiki/Geometric_mean) of the input
-     * @param numbers the input numbers
-     * @throws IllegalArgumentException empty input
+     * Computes the geometric mean of the given numbers.
+     * <p>
+     * The geometric mean is calculated as: ⁿ√(x₁ × x₂ × ... × xₙ)
+     * </p>
+     * <p>
+     * Example: For numbers [2, 8], the geometric mean is √(2×8) = √16 = 4.0
+     * </p>
+     * <p>
+     * Note: This method may produce unexpected results for negative numbers,
+     * as it computes the real-valued nth root which may not exist for negative
+     * products.
+     * </p>
+     *
+     * @param numbers the input numbers (must not be empty)
      * @return the geometric mean of the input numbers
+     * @throws IllegalArgumentException if the input is empty
+     * @see <a href="https://en.wikipedia.org/wiki/Geometric_mean">Geometric
+     *      Mean</a>
      */
     public static Double geometric(final Iterable<Double> numbers) {
         checkIfNotEmpty(numbers);
-        return Math.pow(StreamSupport.stream(numbers.spliterator(), false).reduce((x, y) -> x * y).get(), 1d / IterableUtils.size(numbers));
+        double product = StreamSupport.stream(numbers.spliterator(), false).reduce(1d, (x, y) -> x * y);
+        int size = IterableUtils.size(numbers);
+        return Math.pow(product, 1.0 / size);
     }
 
     /**
-     * @brief computes the [Harmonic Mean](https://en.wikipedia.org/wiki/Harmonic_mean) of the input
-     * @param numbers the input numbers
-     * @throws IllegalArgumentException empty input
+     * Computes the harmonic mean of the given numbers.
+     * <p>
+     * The harmonic mean is calculated as: n / (1/x₁ + 1/x₂ + ... + 1/xₙ)
+     * </p>
+     * <p>
+     * Example: For numbers [1, 2, 4], the harmonic mean is 3/(1/1 + 1/2 + 1/4) =
+     * 3/1.75 ≈ 1.714
+     * </p>
+     * <p>
+     * Note: This method will produce unexpected results if any input number is
+     * zero,
+     * as it involves computing reciprocals.
+     * </p>
+     *
+     * @param numbers the input numbers (must not be empty)
      * @return the harmonic mean of the input numbers
+     * @throws IllegalArgumentException if the input is empty
+     * @see <a href="https://en.wikipedia.org/wiki/Harmonic_mean">Harmonic Mean</a>
      */
     public static Double harmonic(final Iterable<Double> numbers) {
         checkIfNotEmpty(numbers);
-        return IterableUtils.size(numbers) / StreamSupport.stream(numbers.spliterator(), false).reduce(0d, (x, y) -> x + 1d / y);
+        double sumOfReciprocals = StreamSupport.stream(numbers.spliterator(), false).reduce(0d, (x, y) -> x + 1d / y);
+        int size = IterableUtils.size(numbers);
+        return size / sumOfReciprocals;
     }
 
+    /**
+     * Validates that the input iterable is not empty.
+     *
+     * @param numbers the input numbers to validate
+     * @throws IllegalArgumentException if the input is empty
+     */
     private static void checkIfNotEmpty(final Iterable<Double> numbers) {
         if (!numbers.iterator().hasNext()) {
-            throw new IllegalArgumentException("Emtpy list given for Mean computation.");
+            throw new IllegalArgumentException("Empty list given for Mean computation.");
         }
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/MeansTest.java b/src/test/java/com/thealgorithms/maths/MeansTest.java
index 4b3a5df44b34..deee0a931910 100644
--- a/src/test/java/com/thealgorithms/maths/MeansTest.java
+++ b/src/test/java/com/thealgorithms/maths/MeansTest.java
@@ -2,70 +2,217 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.LinkedHashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
+import java.util.TreeSet;
 import java.util.Vector;
-import org.assertj.core.util.Lists;
-import org.assertj.core.util.Sets;
 import org.junit.jupiter.api.Test;
 
+/**
+ * Test class for {@link Means}.
+ * <p>
+ * This class provides comprehensive test coverage for all mean calculation
+ * methods,
+ * including edge cases, various collection types, and error conditions.
+ * </p>
+ */
 class MeansTest {
 
+    private static final double EPSILON = 1e-9;
+
+    // ========== Arithmetic Mean Tests ==========
+
     @Test
-    void arithmeticMeanZeroNumbers() throws IllegalArgumentException {
+    void testArithmeticMeanThrowsExceptionForEmptyList() {
         List<Double> numbers = new ArrayList<>();
-        assertThrows(IllegalArgumentException.class, () -> Means.arithmetic(numbers));
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> Means.arithmetic(numbers));
+        assertTrue(exception.getMessage().contains("Empty list"));
+    }
+
+    @Test
+    void testArithmeticMeanSingleNumber() {
+        List<Double> numbers = Arrays.asList(2.5);
+        assertEquals(2.5, Means.arithmetic(numbers), EPSILON);
+    }
+
+    @Test
+    void testArithmeticMeanTwoNumbers() {
+        List<Double> numbers = Arrays.asList(2.0, 4.0);
+        assertEquals(3.0, Means.arithmetic(numbers), EPSILON);
     }
 
     @Test
-    void geometricMeanZeroNumbers() throws IllegalArgumentException {
+    void testArithmeticMeanMultipleNumbers() {
+        List<Double> numbers = Arrays.asList(1.0, 2.0, 3.0, 4.0, 5.0);
+        assertEquals(3.0, Means.arithmetic(numbers), EPSILON);
+    }
+
+    @Test
+    void testArithmeticMeanWithTreeSet() {
+        Set<Double> numbers = new TreeSet<>(Arrays.asList(1.0, 2.5, 83.3, 25.9999, 46.0001, 74.7, 74.5));
+        assertEquals(44.0, Means.arithmetic(numbers), EPSILON);
+    }
+
+    @Test
+    void testArithmeticMeanWithNegativeNumbers() {
+        List<Double> numbers = Arrays.asList(-5.0, -3.0, -1.0, 1.0, 3.0, 5.0);
+        assertEquals(0.0, Means.arithmetic(numbers), EPSILON);
+    }
+
+    @Test
+    void testArithmeticMeanWithDecimalNumbers() {
+        List<Double> numbers = Arrays.asList(1.1, 2.2, 3.3, 4.4, 5.5);
+        assertEquals(3.3, Means.arithmetic(numbers), EPSILON);
+    }
+
+    @Test
+    void testArithmeticMeanWithVector() {
+        Vector<Double> numbers = new Vector<>(Arrays.asList(10.0, 20.0, 30.0));
+        assertEquals(20.0, Means.arithmetic(numbers), EPSILON);
+    }
+
+    // ========== Geometric Mean Tests ==========
+
+    @Test
+    void testGeometricMeanThrowsExceptionForEmptyList() {
         List<Double> numbers = new ArrayList<>();
-        assertThrows(IllegalArgumentException.class, () -> Means.geometric(numbers));
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> Means.geometric(numbers));
+        assertTrue(exception.getMessage().contains("Empty list"));
     }
 
     @Test
-    void harmonicMeanZeroNumbers() throws IllegalArgumentException {
+    void testGeometricMeanSingleNumber() {
+        Set<Double> numbers = new LinkedHashSet<>(Arrays.asList(2.5));
+        assertEquals(2.5, Means.geometric(numbers), EPSILON);
+    }
+
+    @Test
+    void testGeometricMeanTwoNumbers() {
+        List<Double> numbers = Arrays.asList(2.0, 8.0);
+        assertEquals(4.0, Means.geometric(numbers), EPSILON);
+    }
+
+    @Test
+    void testGeometricMeanMultipleNumbers() {
+        LinkedList<Double> numbers = new LinkedList<>(Arrays.asList(1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 1.25));
+        assertEquals(2.6426195539300585, Means.geometric(numbers), EPSILON);
+    }
+
+    @Test
+    void testGeometricMeanPerfectSquares() {
+        List<Double> numbers = Arrays.asList(1.0, 4.0, 9.0, 16.0);
+        double expected = Math.pow(1.0 * 4.0 * 9.0 * 16.0, 1.0 / 4.0);
+        assertEquals(expected, Means.geometric(numbers), EPSILON);
+    }
+
+    @Test
+    void testGeometricMeanIdenticalNumbers() {
+        List<Double> numbers = Arrays.asList(5.0, 5.0, 5.0, 5.0);
+        assertEquals(5.0, Means.geometric(numbers), EPSILON);
+    }
+
+    @Test
+    void testGeometricMeanWithLinkedHashSet() {
+        LinkedHashSet<Double> numbers = new LinkedHashSet<>(Arrays.asList(2.0, 4.0, 8.0));
+        double expected = Math.pow(2.0 * 4.0 * 8.0, 1.0 / 3.0);
+        assertEquals(expected, Means.geometric(numbers), EPSILON);
+    }
+
+    // ========== Harmonic Mean Tests ==========
+
+    @Test
+    void testHarmonicMeanThrowsExceptionForEmptyList() {
         List<Double> numbers = new ArrayList<>();
-        assertThrows(IllegalArgumentException.class, () -> Means.harmonic(numbers));
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> Means.harmonic(numbers));
+        assertTrue(exception.getMessage().contains("Empty list"));
+    }
+
+    @Test
+    void testHarmonicMeanSingleNumber() {
+        LinkedHashSet<Double> numbers = new LinkedHashSet<>(Arrays.asList(2.5));
+        assertEquals(2.5, Means.harmonic(numbers), EPSILON);
     }
 
     @Test
-    void arithmeticMeanSingleNumber() {
-        List<Double> numbers = Lists.newArrayList(2.5);
-        assertEquals(2.5, Means.arithmetic(numbers));
+    void testHarmonicMeanTwoNumbers() {
+        List<Double> numbers = Arrays.asList(2.0, 4.0);
+        double expected = 2.0 / (1.0 / 2.0 + 1.0 / 4.0);
+        assertEquals(expected, Means.harmonic(numbers), EPSILON);
     }
 
     @Test
-    void geometricMeanSingleNumber() {
-        Set<Double> numbers = Sets.newHashSet(Lists.newArrayList(2.5));
-        assertEquals(2.5, Means.geometric(numbers));
+    void testHarmonicMeanMultipleNumbers() {
+        Vector<Double> numbers = new Vector<>(Arrays.asList(1.0, 2.5, 83.3, 25.9999, 46.0001, 74.7, 74.5));
+        assertEquals(4.6697322801074135, Means.harmonic(numbers), EPSILON);
     }
 
     @Test
-    void harmonicMeanSingleNumber() {
-        LinkedHashSet<Double> numbers = Sets.newLinkedHashSet(2.5);
-        assertEquals(2.5, Means.harmonic(numbers));
+    void testHarmonicMeanThreeNumbers() {
+        List<Double> numbers = Arrays.asList(1.0, 2.0, 4.0);
+        double expected = 3.0 / (1.0 / 1.0 + 1.0 / 2.0 + 1.0 / 4.0);
+        assertEquals(expected, Means.harmonic(numbers), EPSILON);
     }
 
     @Test
-    void arithmeticMeanMultipleNumbers() {
-        Set<Double> numbers = Sets.newTreeSet(1d, 2.5, 83.3, 25.9999, 46.0001, 74.7, 74.5);
-        assertEquals(44, Means.arithmetic(numbers));
+    void testHarmonicMeanIdenticalNumbers() {
+        List<Double> numbers = Arrays.asList(6.0, 6.0, 6.0);
+        assertEquals(6.0, Means.harmonic(numbers), EPSILON);
     }
 
     @Test
-    void geometricMeanMultipleNumbers() {
-        LinkedList<Double> numbers = new LinkedList<>(Lists.newArrayList(1d, 2d, 3d, 4d, 5d, 6d, 1.25));
-        assertEquals(2.6426195539300585, Means.geometric(numbers));
+    void testHarmonicMeanWithLinkedList() {
+        LinkedList<Double> numbers = new LinkedList<>(Arrays.asList(3.0, 6.0, 9.0));
+        double expected = 3.0 / (1.0 / 3.0 + 1.0 / 6.0 + 1.0 / 9.0);
+        assertEquals(expected, Means.harmonic(numbers), EPSILON);
+    }
+
+    // ========== Additional Edge Case Tests ==========
+
+    @Test
+    void testArithmeticMeanWithVeryLargeNumbers() {
+        List<Double> numbers = Arrays.asList(1e100, 2e100, 3e100);
+        assertEquals(2e100, Means.arithmetic(numbers), 1e90);
     }
 
     @Test
-    void harmonicMeanMultipleNumbers() {
-        Vector<Double> numbers = new Vector<>(Lists.newArrayList(1d, 2.5, 83.3, 25.9999, 46.0001, 74.7, 74.5));
-        assertEquals(4.6697322801074135, Means.harmonic(numbers));
+    void testArithmeticMeanWithVerySmallNumbers() {
+        List<Double> numbers = Arrays.asList(1e-100, 2e-100, 3e-100);
+        assertEquals(2e-100, Means.arithmetic(numbers), 1e-110);
+    }
+
+    @Test
+    void testGeometricMeanWithOnes() {
+        List<Double> numbers = Arrays.asList(1.0, 1.0, 1.0, 1.0);
+        assertEquals(1.0, Means.geometric(numbers), EPSILON);
+    }
+
+    @Test
+    void testAllMeansConsistencyForIdenticalValues() {
+        List<Double> numbers = Arrays.asList(7.5, 7.5, 7.5, 7.5);
+        double arithmetic = Means.arithmetic(numbers);
+        double geometric = Means.geometric(numbers);
+        double harmonic = Means.harmonic(numbers);
+
+        assertEquals(7.5, arithmetic, EPSILON);
+        assertEquals(7.5, geometric, EPSILON);
+        assertEquals(7.5, harmonic, EPSILON);
+    }
+
+    @Test
+    void testMeansRelationship() {
+        // For positive numbers, harmonic mean ≤ geometric mean ≤ arithmetic mean
+        List<Double> numbers = Arrays.asList(2.0, 4.0, 8.0);
+        double arithmetic = Means.arithmetic(numbers);
+        double geometric = Means.geometric(numbers);
+        double harmonic = Means.harmonic(numbers);
+
+        assertTrue(harmonic <= geometric, "Harmonic mean should be ≤ geometric mean");
+        assertTrue(geometric <= arithmetic, "Geometric mean should be ≤ arithmetic mean");
     }
 }

From 1437036b194400e47838d83e283531b13348bfc8 Mon Sep 17 00:00:00 2001
From: Sameer Prajapati <sameerprajapati066@gmail.com>
Date: Thu, 16 Oct 2025 02:21:14 +0530
Subject: [PATCH 1028/1338] =?UTF-8?q?feat(graph):=20add=20Push=E2=80=93Rel?=
 =?UTF-8?q?abel=20max=20flow=20with=20tests=20and=20index=20(#6793)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* feat(graph): add Push–Relabel max flow with tests and index

* style(checkstyle): reduce discharge parameter count via State holder

* chore(pmd): make discharge void and remove empty else; satisfy PMD

---------

Co-authored-by: a <alexanderklmn@gmail.com>
---
 DIRECTORY.md                                  |   1 +
 .../com/thealgorithms/graph/PushRelabel.java  | 162 ++++++++++++++++++
 .../thealgorithms/graph/PushRelabelTest.java  |  66 +++++++
 3 files changed, 229 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/PushRelabel.java
 create mode 100644 src/test/java/com/thealgorithms/graph/PushRelabelTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 3bfedac64b89..55a7c7f0a511 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -351,6 +351,7 @@
           - 📄 [ConstrainedShortestPath](src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java)
           - 📄 [HopcroftKarp](src/main/java/com/thealgorithms/graph/HopcroftKarp.java)
           - 📄 [PredecessorConstrainedDfs](src/main/java/com/thealgorithms/graph/PredecessorConstrainedDfs.java)
+          - 📄 [PushRelabel](src/main/java/com/thealgorithms/graph/PushRelabel.java)
           - 📄 [StronglyConnectedComponentOptimized](src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
           - 📄 [TravelingSalesman](src/main/java/com/thealgorithms/graph/TravelingSalesman.java)
           - 📄 [Dinic](src/main/java/com/thealgorithms/graph/Dinic.java)
diff --git a/src/main/java/com/thealgorithms/graph/PushRelabel.java b/src/main/java/com/thealgorithms/graph/PushRelabel.java
new file mode 100644
index 000000000000..1bfb5ceacce0
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/PushRelabel.java
@@ -0,0 +1,162 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.Queue;
+
+/**
+ * Push–Relabel (Relabel-to-Front variant simplified to array scanning) for maximum flow.
+ *
+ * <p>Input graph is a capacity matrix where {@code capacity[u][v]} is the capacity of the edge
+ * {@code u -> v}. Capacities must be non-negative. Vertices are indexed in {@code [0, n)}.
+ *
+ * <p>Time complexity: O(V^3) in the worst case for the array-based variant; typically fast in
+ * practice. This implementation uses a residual network over an adjacency-matrix representation.
+ *
+ * <p>The API mirrors {@link EdmondsKarp#maxFlow(int[][], int, int)} and {@link Dinic#maxFlow(int[][], int, int)}.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Push%E2%80%93relabel_maximum_flow_algorithm">Wikipedia: Push–Relabel maximum flow algorithm</a>
+ */
+public final class PushRelabel {
+
+    private PushRelabel() {
+    }
+
+    /**
+     * Computes the maximum flow from {@code source} to {@code sink} using Push–Relabel.
+     *
+     * @param capacity square capacity matrix (n x n); entries must be >= 0
+     * @param source source vertex index in [0, n)
+     * @param sink sink vertex index in [0, n)
+     * @return the maximum flow value
+     * @throws IllegalArgumentException if inputs are invalid
+     */
+    public static int maxFlow(int[][] capacity, int source, int sink) {
+        validate(capacity, source, sink);
+        final int n = capacity.length;
+        if (source == sink) {
+            return 0;
+        }
+
+        int[][] residual = new int[n][n];
+        for (int i = 0; i < n; i++) {
+            residual[i] = Arrays.copyOf(capacity[i], n);
+        }
+
+        int[] height = new int[n];
+        int[] excess = new int[n];
+        int[] nextNeighbor = new int[n];
+
+        // Preflow initialization
+        height[source] = n;
+        for (int v = 0; v < n; v++) {
+            int cap = residual[source][v];
+            if (cap > 0) {
+                residual[source][v] -= cap;
+                residual[v][source] += cap;
+                excess[v] += cap;
+                excess[source] -= cap;
+            }
+        }
+
+        // Active queue contains vertices (except source/sink) with positive excess
+        Queue<Integer> active = new ArrayDeque<>();
+        for (int v = 0; v < n; v++) {
+            if (v != source && v != sink && excess[v] > 0) {
+                active.add(v);
+            }
+        }
+
+        State state = new State(residual, height, excess, nextNeighbor, source, sink, active);
+
+        while (!active.isEmpty()) {
+            int u = active.poll();
+            discharge(u, state);
+            if (excess[u] > 0) {
+                // still active after discharge; push to back
+                active.add(u);
+            }
+        }
+
+        // Total flow equals excess at sink
+        return excess[sink];
+    }
+
+    private static void discharge(int u, State s) {
+        final int n = s.residual.length;
+        while (s.excess[u] > 0) {
+            if (s.nextNeighbor[u] >= n) {
+                relabel(u, s.residual, s.height);
+                s.nextNeighbor[u] = 0;
+                continue;
+            }
+            int v = s.nextNeighbor[u];
+            if (s.residual[u][v] > 0 && s.height[u] == s.height[v] + 1) {
+                int delta = Math.min(s.excess[u], s.residual[u][v]);
+                s.residual[u][v] -= delta;
+                s.residual[v][u] += delta;
+                s.excess[u] -= delta;
+                int prevExcessV = s.excess[v];
+                s.excess[v] += delta;
+                if (v != s.source && v != s.sink && prevExcessV == 0) {
+                    s.active.add(v);
+                }
+            } else {
+                s.nextNeighbor[u]++;
+            }
+        }
+    }
+
+    private static final class State {
+        final int[][] residual;
+        final int[] height;
+        final int[] excess;
+        final int[] nextNeighbor;
+        final int source;
+        final int sink;
+        final Queue<Integer> active;
+
+        State(int[][] residual, int[] height, int[] excess, int[] nextNeighbor, int source, int sink, Queue<Integer> active) {
+            this.residual = residual;
+            this.height = height;
+            this.excess = excess;
+            this.nextNeighbor = nextNeighbor;
+            this.source = source;
+            this.sink = sink;
+            this.active = active;
+        }
+    }
+
+    private static void relabel(int u, int[][] residual, int[] height) {
+        final int n = residual.length;
+        int minHeight = Integer.MAX_VALUE;
+        for (int v = 0; v < n; v++) {
+            if (residual[u][v] > 0) {
+                minHeight = Math.min(minHeight, height[v]);
+            }
+        }
+        if (minHeight < Integer.MAX_VALUE) {
+            height[u] = minHeight + 1;
+        }
+    }
+
+    private static void validate(int[][] capacity, int source, int sink) {
+        if (capacity == null || capacity.length == 0) {
+            throw new IllegalArgumentException("Capacity matrix must not be null or empty");
+        }
+        int n = capacity.length;
+        for (int i = 0; i < n; i++) {
+            if (capacity[i] == null || capacity[i].length != n) {
+                throw new IllegalArgumentException("Capacity matrix must be square");
+            }
+            for (int j = 0; j < n; j++) {
+                if (capacity[i][j] < 0) {
+                    throw new IllegalArgumentException("Capacities must be non-negative");
+                }
+            }
+        }
+        if (source < 0 || sink < 0 || source >= n || sink >= n) {
+            throw new IllegalArgumentException("Source and sink must be valid vertex indices");
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/PushRelabelTest.java b/src/test/java/com/thealgorithms/graph/PushRelabelTest.java
new file mode 100644
index 000000000000..b0021ec805b8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/PushRelabelTest.java
@@ -0,0 +1,66 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class PushRelabelTest {
+
+    @Test
+    @DisplayName("Classic CLRS network yields max flow 23 (PushRelabel)")
+    void clrsExample() {
+        int[][] capacity = {{0, 16, 13, 0, 0, 0}, {0, 0, 10, 12, 0, 0}, {0, 4, 0, 0, 14, 0}, {0, 0, 9, 0, 0, 20}, {0, 0, 0, 7, 0, 4}, {0, 0, 0, 0, 0, 0}};
+        int maxFlow = PushRelabel.maxFlow(capacity, 0, 5);
+        assertEquals(23, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Disconnected network has zero flow (PushRelabel)")
+    void disconnectedGraph() {
+        int[][] capacity = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};
+        int maxFlow = PushRelabel.maxFlow(capacity, 0, 2);
+        assertEquals(0, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Source equals sink returns zero (PushRelabel)")
+    void sourceEqualsSink() {
+        int[][] capacity = {{0, 5}, {0, 0}};
+        int maxFlow = PushRelabel.maxFlow(capacity, 0, 0);
+        assertEquals(0, maxFlow);
+    }
+
+    @Test
+    @DisplayName("PushRelabel matches Dinic and EdmondsKarp on random small graphs")
+    void parityWithOtherMaxFlow() {
+        java.util.Random rnd = new java.util.Random(42);
+        for (int n = 3; n <= 7; n++) {
+            for (int it = 0; it < 25; it++) {
+                int[][] cap = new int[n][n];
+                for (int i = 0; i < n; i++) {
+                    for (int j = 0; j < n; j++) {
+                        if (i != j && rnd.nextDouble() < 0.35) {
+                            cap[i][j] = rnd.nextInt(10); // capacities 0..9
+                        }
+                    }
+                }
+                int s = 0;
+                int t = n - 1;
+                int fPushRelabel = PushRelabel.maxFlow(copyMatrix(cap), s, t);
+                int fDinic = Dinic.maxFlow(copyMatrix(cap), s, t);
+                int fEdmondsKarp = EdmondsKarp.maxFlow(cap, s, t);
+                assertEquals(fDinic, fPushRelabel);
+                assertEquals(fEdmondsKarp, fPushRelabel);
+            }
+        }
+    }
+
+    private static int[][] copyMatrix(int[][] a) {
+        int[][] b = new int[a.length][a.length];
+        for (int i = 0; i < a.length; i++) {
+            b[i] = java.util.Arrays.copyOf(a[i], a[i].length);
+        }
+        return b;
+    }
+}

From 1a910b52d47a8495d300f1944e9bc546304d4189 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 16 Oct 2025 11:37:36 +0200
Subject: [PATCH 1029/1338] chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.6.0 to 4.9.7.0 (#6796)

chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.6.0 to 4.9.7.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.6.0...spotbugs-maven-plugin-4.9.7.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.7.0
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 250fefd5073f..8a7cba29c908 100644
--- a/pom.xml
+++ b/pom.xml
@@ -119,7 +119,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.6.0</version>
+                <version>4.9.7.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 3519a9149790e8cf07422ee7386a12d981a71374 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Date: Thu, 16 Oct 2025 12:13:40 +0200
Subject: [PATCH 1030/1338] Update DIRECTORY.md (#6546)

Co-authored-by: vil02 <vil02@users.noreply.github.com>
---
 DIRECTORY.md | 101 +++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 97 insertions(+), 4 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 55a7c7f0a511..2d140d829cfd 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -29,8 +29,10 @@
           - 📄 [BcdConversion](src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java)
           - 📄 [BinaryPalindromeCheck](src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java)
           - 📄 [BitSwap](src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
+          - 📄 [BitwiseGCD](src/main/java/com/thealgorithms/bitmanipulation/BitwiseGCD.java)
           - 📄 [BooleanAlgebraGates](src/main/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGates.java)
           - 📄 [ClearLeftmostSetBit](src/main/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBit.java)
+          - 📄 [CountBitsFlip](src/main/java/com/thealgorithms/bitmanipulation/CountBitsFlip.java)
           - 📄 [CountLeadingZeros](src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java)
           - 📄 [CountSetBits](src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
           - 📄 [FindNthBit](src/main/java/com/thealgorithms/bitmanipulation/FindNthBit.java)
@@ -74,6 +76,7 @@
           - 📄 [ECC](src/main/java/com/thealgorithms/ciphers/ECC.java)
           - 📄 [HillCipher](src/main/java/com/thealgorithms/ciphers/HillCipher.java)
           - 📄 [MonoAlphabetic](src/main/java/com/thealgorithms/ciphers/MonoAlphabetic.java)
+          - 📄 [PermutationCipher](src/main/java/com/thealgorithms/ciphers/PermutationCipher.java)
           - 📄 [PlayfairCipher](src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java)
           - 📄 [Polybius](src/main/java/com/thealgorithms/ciphers/Polybius.java)
           - 📄 [ProductCipher](src/main/java/com/thealgorithms/ciphers/ProductCipher.java)
@@ -89,6 +92,9 @@
             - 📄 [CompositeLFSR](src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java)
             - 📄 [LFSR](src/main/java/com/thealgorithms/ciphers/a5/LFSR.java)
             - 📄 [Utils](src/main/java/com/thealgorithms/ciphers/a5/Utils.java)
+        - 📁 **compression**
+          - 📄 [RunLengthEncoding](src/main/java/com/thealgorithms/compression/RunLengthEncoding.java)
+          - 📄 [ShannonFano](src/main/java/com/thealgorithms/compression/ShannonFano.java)
         - 📁 **conversions**
           - 📄 [AffineConverter](src/main/java/com/thealgorithms/conversions/AffineConverter.java)
           - 📄 [AnyBaseToAnyBase](src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java)
@@ -98,6 +104,7 @@
           - 📄 [BinaryToDecimal](src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java)
           - 📄 [BinaryToHexadecimal](src/main/java/com/thealgorithms/conversions/BinaryToHexadecimal.java)
           - 📄 [BinaryToOctal](src/main/java/com/thealgorithms/conversions/BinaryToOctal.java)
+          - 📄 [CoordinateConverter](src/main/java/com/thealgorithms/conversions/CoordinateConverter.java)
           - 📄 [DecimalToAnyBase](src/main/java/com/thealgorithms/conversions/DecimalToAnyBase.java)
           - 📄 [DecimalToBinary](src/main/java/com/thealgorithms/conversions/DecimalToBinary.java)
           - 📄 [DecimalToHexadecimal](src/main/java/com/thealgorithms/conversions/DecimalToHexadecimal.java)
@@ -118,6 +125,7 @@
           - 📄 [PhoneticAlphabetConverter](src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java)
           - 📄 [RgbHsvConversion](src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java)
           - 📄 [RomanToInteger](src/main/java/com/thealgorithms/conversions/RomanToInteger.java)
+          - 📄 [TimeConverter](src/main/java/com/thealgorithms/conversions/TimeConverter.java)
           - 📄 [TurkishToLatinConversion](src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java)
           - 📄 [UnitConversions](src/main/java/com/thealgorithms/conversions/UnitConversions.java)
           - 📄 [UnitsConverter](src/main/java/com/thealgorithms/conversions/UnitsConverter.java)
@@ -157,6 +165,7 @@
             - 📄 [BoruvkaAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithm.java)
             - 📄 [ConnectedComponent](src/main/java/com/thealgorithms/datastructures/graphs/ConnectedComponent.java)
             - 📄 [Cycles](src/main/java/com/thealgorithms/datastructures/graphs/Cycles.java)
+            - 📄 [DialsAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/DialsAlgorithm.java)
             - 📄 [DijkstraAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java)
             - 📄 [DijkstraOptimizedAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java)
             - 📄 [EdmondsBlossomAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithm.java)
@@ -171,9 +180,9 @@
             - 📄 [MatrixGraphs](src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java)
             - 📄 [PrimMST](src/main/java/com/thealgorithms/datastructures/graphs/PrimMST.java)
             - 📄 [TarjansAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithm.java)
+            - 📄 [TwoSat](src/main/java/com/thealgorithms/datastructures/graphs/TwoSat.java)
             - 📄 [UndirectedAdjacencyListGraph](src/main/java/com/thealgorithms/datastructures/graphs/UndirectedAdjacencyListGraph.java)
             - 📄 [WelshPowell](src/main/java/com/thealgorithms/datastructures/graphs/WelshPowell.java)
-            - 📄 [TwoSat](src/main/java/com/thealgorithms/datastructures/graphs/TwoSat.java)
           - 📁 **hashmap**
             - 📁 **hashing**
               - 📄 [GenericHashMapUsingArray](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArray.java)
@@ -200,10 +209,12 @@
             - 📄 [MinPriorityQueue](src/main/java/com/thealgorithms/datastructures/heaps/MinPriorityQueue.java)
           - 📁 **lists**
             - 📄 [CircleLinkedList](src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java)
+            - 📄 [CircularDoublyLinkedList](src/main/java/com/thealgorithms/datastructures/lists/CircularDoublyLinkedList.java)
             - 📄 [CountSinglyLinkedListRecursion](src/main/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursion.java)
             - 📄 [CreateAndDetectLoop](src/main/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoop.java)
             - 📄 [CursorLinkedList](src/main/java/com/thealgorithms/datastructures/lists/CursorLinkedList.java)
             - 📄 [DoublyLinkedList](src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java)
+            - 📄 [FlattenMultilevelLinkedList](src/main/java/com/thealgorithms/datastructures/lists/FlattenMultilevelLinkedList.java)
             - 📄 [MergeKSortedLinkedList](src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java)
             - 📄 [MergeSortedArrayList](src/main/java/com/thealgorithms/datastructures/lists/MergeSortedArrayList.java)
             - 📄 [MergeSortedSinglyLinkedList](src/main/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedList.java)
@@ -216,6 +227,7 @@
             - 📄 [SinglyLinkedListNode](src/main/java/com/thealgorithms/datastructures/lists/SinglyLinkedListNode.java)
             - 📄 [SkipList](src/main/java/com/thealgorithms/datastructures/lists/SkipList.java)
             - 📄 [SortedLinkedList](src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java)
+            - 📄 [TortoiseHareAlgo](src/main/java/com/thealgorithms/datastructures/lists/TortoiseHareAlgo.java)
           - 📁 **queues**
             - 📄 [CircularQueue](src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java)
             - 📄 [Deque](src/main/java/com/thealgorithms/datastructures/queues/Deque.java)
@@ -300,6 +312,7 @@
           - 📄 [ClimbingStairs](src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java)
           - 📄 [CoinChange](src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java)
           - 📄 [CountFriendsPairing](src/main/java/com/thealgorithms/dynamicprogramming/CountFriendsPairing.java)
+          - 📄 [DamerauLevenshteinDistance](src/main/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistance.java)
           - 📄 [DiceThrow](src/main/java/com/thealgorithms/dynamicprogramming/DiceThrow.java)
           - 📄 [EditDistance](src/main/java/com/thealgorithms/dynamicprogramming/EditDistance.java)
           - 📄 [EggDropping](src/main/java/com/thealgorithms/dynamicprogramming/EggDropping.java)
@@ -320,9 +333,11 @@
           - 📄 [LongestValidParentheses](src/main/java/com/thealgorithms/dynamicprogramming/LongestValidParentheses.java)
           - 📄 [MatrixChainMultiplication](src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplication.java)
           - 📄 [MatrixChainRecursiveTopDownMemoisation](src/main/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisation.java)
+          - 📄 [MaximumProductSubarray](src/main/java/com/thealgorithms/dynamicprogramming/MaximumProductSubarray.java)
           - 📄 [MaximumSumOfNonAdjacentElements](src/main/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElements.java)
           - 📄 [MinimumPathSum](src/main/java/com/thealgorithms/dynamicprogramming/MinimumPathSum.java)
           - 📄 [MinimumSumPartition](src/main/java/com/thealgorithms/dynamicprogramming/MinimumSumPartition.java)
+          - 📄 [NeedlemanWunsch](src/main/java/com/thealgorithms/dynamicprogramming/NeedlemanWunsch.java)
           - 📄 [NewManShanksPrime](src/main/java/com/thealgorithms/dynamicprogramming/NewManShanksPrime.java)
           - 📄 [OptimalJobScheduling](src/main/java/com/thealgorithms/dynamicprogramming/OptimalJobScheduling.java)
           - 📄 [PalindromicPartitioning](src/main/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioning.java)
@@ -330,6 +345,7 @@
           - 📄 [RegexMatching](src/main/java/com/thealgorithms/dynamicprogramming/RegexMatching.java)
           - 📄 [RodCutting](src/main/java/com/thealgorithms/dynamicprogramming/RodCutting.java)
           - 📄 [ShortestCommonSupersequenceLength](src/main/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLength.java)
+          - 📄 [SmithWaterman](src/main/java/com/thealgorithms/dynamicprogramming/SmithWaterman.java)
           - 📄 [SubsetCount](src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java)
           - 📄 [SubsetSum](src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java)
           - 📄 [SubsetSumSpaceOptimized](src/main/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimized.java)
@@ -344,18 +360,24 @@
           - 📄 [BresenhamLine](src/main/java/com/thealgorithms/geometry/BresenhamLine.java)
           - 📄 [ConvexHull](src/main/java/com/thealgorithms/geometry/ConvexHull.java)
           - 📄 [GrahamScan](src/main/java/com/thealgorithms/geometry/GrahamScan.java)
+          - 📄 [Haversine](src/main/java/com/thealgorithms/geometry/Haversine.java)
           - 📄 [MidpointCircle](src/main/java/com/thealgorithms/geometry/MidpointCircle.java)
           - 📄 [MidpointEllipse](src/main/java/com/thealgorithms/geometry/MidpointEllipse.java)
           - 📄 [Point](src/main/java/com/thealgorithms/geometry/Point.java)
+          - 📄 [WusLine](src/main/java/com/thealgorithms/geometry/WusLine.java)
         - 📁 **graph**
+          - 📄 [BronKerbosch](src/main/java/com/thealgorithms/graph/BronKerbosch.java)
           - 📄 [ConstrainedShortestPath](src/main/java/com/thealgorithms/graph/ConstrainedShortestPath.java)
+          - 📄 [Dinic](src/main/java/com/thealgorithms/graph/Dinic.java)
+          - 📄 [Edmonds](src/main/java/com/thealgorithms/graph/Edmonds.java)
+          - 📄 [EdmondsKarp](src/main/java/com/thealgorithms/graph/EdmondsKarp.java)
           - 📄 [HopcroftKarp](src/main/java/com/thealgorithms/graph/HopcroftKarp.java)
           - 📄 [PredecessorConstrainedDfs](src/main/java/com/thealgorithms/graph/PredecessorConstrainedDfs.java)
           - 📄 [PushRelabel](src/main/java/com/thealgorithms/graph/PushRelabel.java)
           - 📄 [StronglyConnectedComponentOptimized](src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
           - 📄 [TravelingSalesman](src/main/java/com/thealgorithms/graph/TravelingSalesman.java)
-          - 📄 [Dinic](src/main/java/com/thealgorithms/graph/Dinic.java)
           - 📄 [YensKShortestPaths](src/main/java/com/thealgorithms/graph/YensKShortestPaths.java)
+          - 📄 [ZeroOneBfs](src/main/java/com/thealgorithms/graph/ZeroOneBfs.java)
         - 📁 **greedyalgorithms**
           - 📄 [ActivitySelection](src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java)
           - 📄 [BandwidthAllocation](src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java)
@@ -408,6 +430,7 @@
           - 📄 [DistanceFormula](src/main/java/com/thealgorithms/maths/DistanceFormula.java)
           - 📄 [DudeneyNumber](src/main/java/com/thealgorithms/maths/DudeneyNumber.java)
           - 📄 [EulerMethod](src/main/java/com/thealgorithms/maths/EulerMethod.java)
+          - 📄 [EulerPseudoprime](src/main/java/com/thealgorithms/maths/EulerPseudoprime.java)
           - 📄 [EulersFunction](src/main/java/com/thealgorithms/maths/EulersFunction.java)
           - 📄 [FFT](src/main/java/com/thealgorithms/maths/FFT.java)
           - 📄 [FFTBluestein](src/main/java/com/thealgorithms/maths/FFTBluestein.java)
@@ -430,7 +453,9 @@
           - 📄 [GCDRecursion](src/main/java/com/thealgorithms/maths/GCDRecursion.java)
           - 📄 [Gaussian](src/main/java/com/thealgorithms/maths/Gaussian.java)
           - 📄 [GenericRoot](src/main/java/com/thealgorithms/maths/GenericRoot.java)
+          - 📄 [GermainPrimeAndSafePrime](src/main/java/com/thealgorithms/maths/GermainPrimeAndSafePrime.java)
           - 📄 [GoldbachConjecture](src/main/java/com/thealgorithms/maths/GoldbachConjecture.java)
+          - 📄 [HappyNumber](src/main/java/com/thealgorithms/maths/HappyNumber.java)
           - 📄 [HarshadNumber](src/main/java/com/thealgorithms/maths/HarshadNumber.java)
           - 📄 [HeronsFormula](src/main/java/com/thealgorithms/maths/HeronsFormula.java)
           - 📄 [JosephusProblem](src/main/java/com/thealgorithms/maths/JosephusProblem.java)
@@ -454,6 +479,7 @@
           - 📄 [NonRepeatingElement](src/main/java/com/thealgorithms/maths/NonRepeatingElement.java)
           - 📄 [NthUglyNumber](src/main/java/com/thealgorithms/maths/NthUglyNumber.java)
           - 📄 [NumberOfDigits](src/main/java/com/thealgorithms/maths/NumberOfDigits.java)
+          - 📄 [NumberPersistence](src/main/java/com/thealgorithms/maths/NumberPersistence.java)
           - 📄 [PalindromeNumber](src/main/java/com/thealgorithms/maths/PalindromeNumber.java)
           - 📄 [ParseInteger](src/main/java/com/thealgorithms/maths/ParseInteger.java)
           - 📄 [PascalTriangle](src/main/java/com/thealgorithms/maths/PascalTriangle.java)
@@ -461,6 +487,7 @@
           - 📄 [PerfectNumber](src/main/java/com/thealgorithms/maths/PerfectNumber.java)
           - 📄 [PerfectSquare](src/main/java/com/thealgorithms/maths/PerfectSquare.java)
           - 📄 [Perimeter](src/main/java/com/thealgorithms/maths/Perimeter.java)
+          - 📄 [PiApproximation](src/main/java/com/thealgorithms/maths/PiApproximation.java)
           - 📄 [PiNilakantha](src/main/java/com/thealgorithms/maths/PiNilakantha.java)
           - 📄 [PollardRho](src/main/java/com/thealgorithms/maths/PollardRho.java)
           - 📄 [Pow](src/main/java/com/thealgorithms/maths/Pow.java)
@@ -479,6 +506,7 @@
           - 📄 [ReverseNumber](src/main/java/com/thealgorithms/maths/ReverseNumber.java)
           - 📄 [RomanNumeralUtil](src/main/java/com/thealgorithms/maths/RomanNumeralUtil.java)
           - 📄 [SecondMinMax](src/main/java/com/thealgorithms/maths/SecondMinMax.java)
+          - 📄 [SieveOfAtkin](src/main/java/com/thealgorithms/maths/SieveOfAtkin.java)
           - 📄 [SieveOfEratosthenes](src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java)
           - 📄 [SimpsonIntegration](src/main/java/com/thealgorithms/maths/SimpsonIntegration.java)
           - 📄 [SolovayStrassenPrimalityTest](src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java)
@@ -490,6 +518,7 @@
           - 📄 [SumOfArithmeticSeries](src/main/java/com/thealgorithms/maths/SumOfArithmeticSeries.java)
           - 📄 [SumOfDigits](src/main/java/com/thealgorithms/maths/SumOfDigits.java)
           - 📄 [SumOfOddNumbers](src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java)
+          - 📄 [SumOfSquares](src/main/java/com/thealgorithms/maths/SumOfSquares.java)
           - 📄 [SumWithoutArithmeticOperators](src/main/java/com/thealgorithms/maths/SumWithoutArithmeticOperators.java)
           - 📄 [TrinomialTriangle](src/main/java/com/thealgorithms/maths/TrinomialTriangle.java)
           - 📄 [TwinPrime](src/main/java/com/thealgorithms/maths/TwinPrime.java)
@@ -497,6 +526,7 @@
           - 📄 [VampireNumber](src/main/java/com/thealgorithms/maths/VampireNumber.java)
           - 📄 [VectorCrossProduct](src/main/java/com/thealgorithms/maths/VectorCrossProduct.java)
           - 📄 [Volume](src/main/java/com/thealgorithms/maths/Volume.java)
+          - 📄 [ZellersCongruence](src/main/java/com/thealgorithms/maths/ZellersCongruence.java)
         - 📁 **matrix**
           - 📄 [InverseOfMatrix](src/main/java/com/thealgorithms/matrix/InverseOfMatrix.java)
           - 📄 [MatrixMultiplication](src/main/java/com/thealgorithms/matrix/MatrixMultiplication.java)
@@ -542,12 +572,11 @@
           - 📄 [Dijkstra](src/main/java/com/thealgorithms/others/Dijkstra.java)
           - 📄 [FloydTriangle](src/main/java/com/thealgorithms/others/FloydTriangle.java)
           - 📄 [GaussLegendre](src/main/java/com/thealgorithms/others/GaussLegendre.java)
-          - 📄 [HappyNumbersSeq](src/main/java/com/thealgorithms/others/HappyNumbersSeq.java)
           - 📄 [Huffman](src/main/java/com/thealgorithms/others/Huffman.java)
           - 📄 [Implementing_auto_completing_features_using_trie](src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java)
           - 📄 [InsertDeleteInArray](src/main/java/com/thealgorithms/others/InsertDeleteInArray.java)
+          - 📄 [IterativeFloodFill](src/main/java/com/thealgorithms/others/IterativeFloodFill.java)
           - 📄 [KochSnowflake](src/main/java/com/thealgorithms/others/KochSnowflake.java)
-          - 📄 [Krishnamurthy](src/main/java/com/thealgorithms/others/Krishnamurthy.java)
           - 📄 [LineSweep](src/main/java/com/thealgorithms/others/LineSweep.java)
           - 📄 [LinearCongruentialGenerator](src/main/java/com/thealgorithms/others/LinearCongruentialGenerator.java)
           - 📄 [LowestBasePalindrome](src/main/java/com/thealgorithms/others/LowestBasePalindrome.java)
@@ -556,6 +585,7 @@
           - 📄 [MaximumSumOfDistinctSubarraysWithLengthK](src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java)
           - 📄 [MemoryManagementAlgorithms](src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java)
           - 📄 [MiniMaxAlgorithm](src/main/java/com/thealgorithms/others/MiniMaxAlgorithm.java)
+          - 📄 [MosAlgorithm](src/main/java/com/thealgorithms/others/MosAlgorithm.java)
           - 📄 [PageRank](src/main/java/com/thealgorithms/others/PageRank.java)
           - 📄 [PasswordGen](src/main/java/com/thealgorithms/others/PasswordGen.java)
           - 📄 [PerlinNoise](src/main/java/com/thealgorithms/others/PerlinNoise.java)
@@ -566,6 +596,8 @@
           - 📄 [Verhoeff](src/main/java/com/thealgorithms/others/Verhoeff.java)
           - 📁 **cn**
             - 📄 [HammingDistance](src/main/java/com/thealgorithms/others/cn/HammingDistance.java)
+        - 📁 **physics**
+          - 📄 [GroundToGroundProjectileMotion](src/main/java/com/thealgorithms/physics/GroundToGroundProjectileMotion.java)
         - 📁 **puzzlesandgames**
           - 📄 [Sudoku](src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java)
           - 📄 [TowerOfHanoi](src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java)
@@ -578,8 +610,10 @@
           - 📄 [RandomizedQuickSort](src/main/java/com/thealgorithms/randomized/RandomizedQuickSort.java)
           - 📄 [ReservoirSampling](src/main/java/com/thealgorithms/randomized/ReservoirSampling.java)
         - 📁 **recursion**
+          - 📄 [DiceThrower](src/main/java/com/thealgorithms/recursion/DiceThrower.java)
           - 📄 [FibonacciSeries](src/main/java/com/thealgorithms/recursion/FibonacciSeries.java)
           - 📄 [GenerateSubsets](src/main/java/com/thealgorithms/recursion/GenerateSubsets.java)
+          - 📄 [SylvesterSequence](src/main/java/com/thealgorithms/recursion/SylvesterSequence.java)
         - 📁 **scheduling**
           - 📄 [AgingScheduling](src/main/java/com/thealgorithms/scheduling/AgingScheduling.java)
           - 📄 [EDFScheduling](src/main/java/com/thealgorithms/scheduling/EDFScheduling.java)
@@ -634,6 +668,7 @@
           - 📄 [RowColumnWiseSorted2dArrayBinarySearch](src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java)
           - 📄 [SaddlebackSearch](src/main/java/com/thealgorithms/searches/SaddlebackSearch.java)
           - 📄 [SearchInARowAndColWiseSortedMatrix](src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java)
+          - 📄 [SentinelLinearSearch](src/main/java/com/thealgorithms/searches/SentinelLinearSearch.java)
           - 📄 [SortOrderAgnosticBinarySearch](src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java)
           - 📄 [SquareRootBinarySearch](src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java)
           - 📄 [TernarySearch](src/main/java/com/thealgorithms/searches/TernarySearch.java)
@@ -645,6 +680,7 @@
           - 📄 [MaxSumKSizeSubarray](src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java)
           - 📄 [MaximumSlidingWindow](src/main/java/com/thealgorithms/slidingwindow/MaximumSlidingWindow.java)
           - 📄 [MinSumKSizeSubarray](src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java)
+          - 📄 [MinimumWindowSubstring](src/main/java/com/thealgorithms/slidingwindow/MinimumWindowSubstring.java)
           - 📄 [ShortestCoprimeSegment](src/main/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegment.java)
         - 📁 **sorts**
           - 📄 [AdaptiveMergeSort](src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java)
@@ -723,6 +759,7 @@
         - 📁 **strings**
           - 📄 [AhoCorasick](src/main/java/com/thealgorithms/strings/AhoCorasick.java)
           - 📄 [Alphabetical](src/main/java/com/thealgorithms/strings/Alphabetical.java)
+          - 📄 [AlternativeStringArrange](src/main/java/com/thealgorithms/strings/AlternativeStringArrange.java)
           - 📄 [Anagrams](src/main/java/com/thealgorithms/strings/Anagrams.java)
           - 📄 [CharactersSame](src/main/java/com/thealgorithms/strings/CharactersSame.java)
           - 📄 [CheckVowels](src/main/java/com/thealgorithms/strings/CheckVowels.java)
@@ -730,6 +767,7 @@
           - 📄 [CountWords](src/main/java/com/thealgorithms/strings/CountWords.java)
           - 📄 [HammingDistance](src/main/java/com/thealgorithms/strings/HammingDistance.java)
           - 📄 [HorspoolSearch](src/main/java/com/thealgorithms/strings/HorspoolSearch.java)
+          - 📄 [Isogram](src/main/java/com/thealgorithms/strings/Isogram.java)
           - 📄 [Isomorphic](src/main/java/com/thealgorithms/strings/Isomorphic.java)
           - 📄 [KMP](src/main/java/com/thealgorithms/strings/KMP.java)
           - 📄 [LetterCombinationsOfPhoneNumber](src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java)
@@ -785,8 +823,10 @@
           - 📄 [BcdConversionTest](src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java)
           - 📄 [BinaryPalindromeCheckTest](src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java)
           - 📄 [BitSwapTest](src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
+          - 📄 [BitwiseGCDTest](src/test/java/com/thealgorithms/bitmanipulation/BitwiseGCDTest.java)
           - 📄 [BooleanAlgebraGatesTest](src/test/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGatesTest.java)
           - 📄 [ClearLeftmostSetBitTest](src/test/java/com/thealgorithms/bitmanipulation/ClearLeftmostSetBitTest.java)
+          - 📄 [CountBitsFlipTest](src/test/java/com/thealgorithms/bitmanipulation/CountBitsFlipTest.java)
           - 📄 [CountLeadingZerosTest](src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java)
           - 📄 [CountSetBitsTest](src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
           - 📄 [FindNthBitTest](src/test/java/com/thealgorithms/bitmanipulation/FindNthBitTest.java)
@@ -829,6 +869,7 @@
           - 📄 [ECCTest](src/test/java/com/thealgorithms/ciphers/ECCTest.java)
           - 📄 [HillCipherTest](src/test/java/com/thealgorithms/ciphers/HillCipherTest.java)
           - 📄 [MonoAlphabeticTest](src/test/java/com/thealgorithms/ciphers/MonoAlphabeticTest.java)
+          - 📄 [PermutationCipherTest](src/test/java/com/thealgorithms/ciphers/PermutationCipherTest.java)
           - 📄 [PlayfairTest](src/test/java/com/thealgorithms/ciphers/PlayfairTest.java)
           - 📄 [PolybiusTest](src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
           - 📄 [RSATest](src/test/java/com/thealgorithms/ciphers/RSATest.java)
@@ -840,6 +881,9 @@
             - 📄 [A5CipherTest](src/test/java/com/thealgorithms/ciphers/a5/A5CipherTest.java)
             - 📄 [A5KeyStreamGeneratorTest](src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java)
             - 📄 [LFSRTest](src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
+        - 📁 **compression**
+          - 📄 [RunLengthEncodingTest](src/test/java/com/thealgorithms/compression/RunLengthEncodingTest.java)
+          - 📄 [ShannonFanoTest](src/test/java/com/thealgorithms/compression/ShannonFanoTest.java)
         - 📁 **conversions**
           - 📄 [AffineConverterTest](src/test/java/com/thealgorithms/conversions/AffineConverterTest.java)
           - 📄 [AnyBaseToDecimalTest](src/test/java/com/thealgorithms/conversions/AnyBaseToDecimalTest.java)
@@ -848,6 +892,7 @@
           - 📄 [BinaryToDecimalTest](src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java)
           - 📄 [BinaryToHexadecimalTest](src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java)
           - 📄 [BinaryToOctalTest](src/test/java/com/thealgorithms/conversions/BinaryToOctalTest.java)
+          - 📄 [CoordinateConverterTest](src/test/java/com/thealgorithms/conversions/CoordinateConverterTest.java)
           - 📄 [DecimalToAnyBaseTest](src/test/java/com/thealgorithms/conversions/DecimalToAnyBaseTest.java)
           - 📄 [DecimalToBinaryTest](src/test/java/com/thealgorithms/conversions/DecimalToBinaryTest.java)
           - 📄 [DecimalToHexadecimalTest](src/test/java/com/thealgorithms/conversions/DecimalToHexadecimalTest.java)
@@ -867,6 +912,7 @@
           - 📄 [OctalToHexadecimalTest](src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
           - 📄 [PhoneticAlphabetConverterTest](src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java)
           - 📄 [RomanToIntegerTest](src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java)
+          - 📄 [TimeConverterTest](src/test/java/com/thealgorithms/conversions/TimeConverterTest.java)
           - 📄 [TurkishToLatinConversionTest](src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java)
           - 📄 [UnitConversionsTest](src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java)
           - 📄 [UnitsConverterTest](src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java)
@@ -901,6 +947,7 @@
             - 📄 [AStarTest](src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java)
             - 📄 [BipartiteGraphDFSTest](src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java)
             - 📄 [BoruvkaAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
+            - 📄 [DialsAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/DialsAlgorithmTest.java)
             - 📄 [DijkstraAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java)
             - 📄 [DijkstraOptimizedAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java)
             - 📄 [EdmondsBlossomAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/EdmondsBlossomAlgorithmTest.java)
@@ -914,6 +961,7 @@
             - 📄 [MatrixGraphsTest](src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java)
             - 📄 [PrimMSTTest](src/test/java/com/thealgorithms/datastructures/graphs/PrimMSTTest.java)
             - 📄 [TarjansAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/TarjansAlgorithmTest.java)
+            - 📄 [TwoSatTest](src/test/java/com/thealgorithms/datastructures/graphs/TwoSatTest.java)
             - 📄 [WelshPowellTest](src/test/java/com/thealgorithms/datastructures/graphs/WelshPowellTest.java)
           - 📁 **hashmap**
             - 📁 **hashing**
@@ -938,9 +986,11 @@
             - 📄 [MinPriorityQueueTest](src/test/java/com/thealgorithms/datastructures/heaps/MinPriorityQueueTest.java)
           - 📁 **lists**
             - 📄 [CircleLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
+            - 📄 [CircularDoublyLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/CircularDoublyLinkedListTest.java)
             - 📄 [CountSinglyLinkedListRecursionTest](src/test/java/com/thealgorithms/datastructures/lists/CountSinglyLinkedListRecursionTest.java)
             - 📄 [CreateAndDetectLoopTest](src/test/java/com/thealgorithms/datastructures/lists/CreateAndDetectLoopTest.java)
             - 📄 [CursorLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/CursorLinkedListTest.java)
+            - 📄 [FlattenMultilevelLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/FlattenMultilevelLinkedListTest.java)
             - 📄 [MergeKSortedLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java)
             - 📄 [MergeSortedArrayListTest](src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java)
             - 📄 [MergeSortedSinglyLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/MergeSortedSinglyLinkedListTest.java)
@@ -951,6 +1001,7 @@
             - 📄 [SinglyLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java)
             - 📄 [SkipListTest](src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java)
             - 📄 [SortedLinkedListTest](src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java)
+            - 📄 [TortoiseHareAlgoTest](src/test/java/com/thealgorithms/datastructures/lists/TortoiseHareAlgoTest.java)
           - 📁 **queues**
             - 📄 [CircularQueueTest](src/test/java/com/thealgorithms/datastructures/queues/CircularQueueTest.java)
             - 📄 [DequeTest](src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java)
@@ -971,6 +1022,7 @@
             - 📄 [AVLTreeTest](src/test/java/com/thealgorithms/datastructures/trees/AVLTreeTest.java)
             - 📄 [BSTFromSortedArrayTest](src/test/java/com/thealgorithms/datastructures/trees/BSTFromSortedArrayTest.java)
             - 📄 [BSTIterativeTest](src/test/java/com/thealgorithms/datastructures/trees/BSTIterativeTest.java)
+            - 📄 [BSTRecursiveGenericTest](src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveGenericTest.java)
             - 📄 [BSTRecursiveTest](src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveTest.java)
             - 📄 [BTreeTest](src/test/java/com/thealgorithms/datastructures/trees/BTreeTest.java)
             - 📄 [BinaryTreeTest](src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java)
@@ -994,6 +1046,9 @@
             - 📄 [TrieTest](src/test/java/com/thealgorithms/datastructures/trees/TrieTest.java)
             - 📄 [VerticalOrderTraversalTest](src/test/java/com/thealgorithms/datastructures/trees/VerticalOrderTraversalTest.java)
             - 📄 [ZigzagTraversalTest](src/test/java/com/thealgorithms/datastructures/trees/ZigzagTraversalTest.java)
+        - 📁 **devutils**
+          - 📁 **entities**
+            - 📄 [ProcessDetailsTest](src/test/java/com/thealgorithms/devutils/entities/ProcessDetailsTest.java)
         - 📁 **divideandconquer**
           - 📄 [BinaryExponentiationTest](src/test/java/com/thealgorithms/divideandconquer/BinaryExponentiationTest.java)
           - 📄 [ClosestPairTest](src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java)
@@ -1014,6 +1069,7 @@
           - 📄 [CoinChangeTest](src/test/java/com/thealgorithms/dynamicprogramming/CoinChangeTest.java)
           - 📄 [CountFriendsPairingTest](src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java)
           - 📄 [DPTest](src/test/java/com/thealgorithms/dynamicprogramming/DPTest.java)
+          - 📄 [DamerauLevenshteinDistanceTest](src/test/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistanceTest.java)
           - 📄 [EditDistanceTest](src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java)
           - 📄 [EggDroppingTest](src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
           - 📄 [FibonacciTest](src/test/java/com/thealgorithms/dynamicprogramming/FibonacciTest.java)
@@ -1032,9 +1088,11 @@
           - 📄 [LongestValidParenthesesTest](src/test/java/com/thealgorithms/dynamicprogramming/LongestValidParenthesesTest.java)
           - 📄 [MatrixChainMultiplicationTest](src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainMultiplicationTest.java)
           - 📄 [MatrixChainRecursiveTopDownMemoisationTest](src/test/java/com/thealgorithms/dynamicprogramming/MatrixChainRecursiveTopDownMemoisationTest.java)
+          - 📄 [MaximumProductSubarrayTest](src/test/java/com/thealgorithms/dynamicprogramming/MaximumProductSubarrayTest.java)
           - 📄 [MaximumSumOfNonAdjacentElementsTest](src/test/java/com/thealgorithms/dynamicprogramming/MaximumSumOfNonAdjacentElementsTest.java)
           - 📄 [MinimumPathSumTest](src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java)
           - 📄 [MinimumSumPartitionTest](src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java)
+          - 📄 [NeedlemanWunschTest](src/test/java/com/thealgorithms/dynamicprogramming/NeedlemanWunschTest.java)
           - 📄 [NewManShanksPrimeTest](src/test/java/com/thealgorithms/dynamicprogramming/NewManShanksPrimeTest.java)
           - 📄 [OptimalJobSchedulingTest](src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
           - 📄 [PalindromicPartitioningTest](src/test/java/com/thealgorithms/dynamicprogramming/PalindromicPartitioningTest.java)
@@ -1042,6 +1100,7 @@
           - 📄 [RegexMatchingTest](src/test/java/com/thealgorithms/dynamicprogramming/RegexMatchingTest.java)
           - 📄 [RodCuttingTest](src/test/java/com/thealgorithms/dynamicprogramming/RodCuttingTest.java)
           - 📄 [ShortestCommonSupersequenceLengthTest](src/test/java/com/thealgorithms/dynamicprogramming/ShortestCommonSupersequenceLengthTest.java)
+          - 📄 [SmithWatermanTest](src/test/java/com/thealgorithms/dynamicprogramming/SmithWatermanTest.java)
           - 📄 [SubsetCountTest](src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java)
           - 📄 [SubsetSumSpaceOptimizedTest](src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumSpaceOptimizedTest.java)
           - 📄 [SubsetSumTest](src/test/java/com/thealgorithms/dynamicprogramming/SubsetSumTest.java)
@@ -1056,15 +1115,24 @@
           - 📄 [BresenhamLineTest](src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java)
           - 📄 [ConvexHullTest](src/test/java/com/thealgorithms/geometry/ConvexHullTest.java)
           - 📄 [GrahamScanTest](src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
+          - 📄 [HaversineTest](src/test/java/com/thealgorithms/geometry/HaversineTest.java)
           - 📄 [MidpointCircleTest](src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java)
           - 📄 [MidpointEllipseTest](src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java)
           - 📄 [PointTest](src/test/java/com/thealgorithms/geometry/PointTest.java)
+          - 📄 [WusLineTest](src/test/java/com/thealgorithms/geometry/WusLineTest.java)
         - 📁 **graph**
+          - 📄 [BronKerboschTest](src/test/java/com/thealgorithms/graph/BronKerboschTest.java)
           - 📄 [ConstrainedShortestPathTest](src/test/java/com/thealgorithms/graph/ConstrainedShortestPathTest.java)
+          - 📄 [DinicTest](src/test/java/com/thealgorithms/graph/DinicTest.java)
+          - 📄 [EdmondsKarpTest](src/test/java/com/thealgorithms/graph/EdmondsKarpTest.java)
+          - 📄 [EdmondsTest](src/test/java/com/thealgorithms/graph/EdmondsTest.java)
           - 📄 [HopcroftKarpTest](src/test/java/com/thealgorithms/graph/HopcroftKarpTest.java)
           - 📄 [PredecessorConstrainedDfsTest](src/test/java/com/thealgorithms/graph/PredecessorConstrainedDfsTest.java)
+          - 📄 [PushRelabelTest](src/test/java/com/thealgorithms/graph/PushRelabelTest.java)
           - 📄 [StronglyConnectedComponentOptimizedTest](src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)
           - 📄 [TravelingSalesmanTest](src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java)
+          - 📄 [YensKShortestPathsTest](src/test/java/com/thealgorithms/graph/YensKShortestPathsTest.java)
+          - 📄 [ZeroOneBfsTest](src/test/java/com/thealgorithms/graph/ZeroOneBfsTest.java)
         - 📁 **greedyalgorithms**
           - 📄 [ActivitySelectionTest](src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java)
           - 📄 [BandwidthAllocationTest](src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java)
@@ -1113,6 +1181,7 @@
           - 📄 [DistanceFormulaTest](src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java)
           - 📄 [DudeneyNumberTest](src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java)
           - 📄 [EulerMethodTest](src/test/java/com/thealgorithms/maths/EulerMethodTest.java)
+          - 📄 [EulerPseudoprimeTest](src/test/java/com/thealgorithms/maths/EulerPseudoprimeTest.java)
           - 📄 [EulersFunctionTest](src/test/java/com/thealgorithms/maths/EulersFunctionTest.java)
           - 📄 [FFTTest](src/test/java/com/thealgorithms/maths/FFTTest.java)
           - 📄 [FactorialRecursionTest](src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java)
@@ -1134,15 +1203,19 @@
           - 📄 [GCDTest](src/test/java/com/thealgorithms/maths/GCDTest.java)
           - 📄 [GaussianTest](src/test/java/com/thealgorithms/maths/GaussianTest.java)
           - 📄 [GenericRootTest](src/test/java/com/thealgorithms/maths/GenericRootTest.java)
+          - 📄 [GermainPrimeAndSafePrimeTest](src/test/java/com/thealgorithms/maths/GermainPrimeAndSafePrimeTest.java)
           - 📄 [GoldbachConjectureTest](src/test/java/com/thealgorithms/maths/GoldbachConjectureTest.java)
+          - 📄 [HappyNumberTest](src/test/java/com/thealgorithms/maths/HappyNumberTest.java)
           - 📄 [HarshadNumberTest](src/test/java/com/thealgorithms/maths/HarshadNumberTest.java)
           - 📄 [HeronsFormulaTest](src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java)
           - 📄 [JosephusProblemTest](src/test/java/com/thealgorithms/maths/JosephusProblemTest.java)
           - 📄 [KaprekarNumbersTest](src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java)
           - 📄 [KaratsubaMultiplicationTest](src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java)
+          - 📄 [KeithNumberTest](src/test/java/com/thealgorithms/maths/KeithNumberTest.java)
           - 📄 [KrishnamurthyNumberTest](src/test/java/com/thealgorithms/maths/KrishnamurthyNumberTest.java)
           - 📄 [LeastCommonMultipleTest](src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java)
           - 📄 [LeonardoNumberTest](src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java)
+          - 📄 [LinearDiophantineEquationsSolverTest](src/test/java/com/thealgorithms/maths/LinearDiophantineEquationsSolverTest.java)
           - 📄 [LongDivisionTest](src/test/java/com/thealgorithms/maths/LongDivisionTest.java)
           - 📄 [LucasSeriesTest](src/test/java/com/thealgorithms/maths/LucasSeriesTest.java)
           - 📄 [MathBuilderTest](src/test/java/com/thealgorithms/maths/MathBuilderTest.java)
@@ -1154,6 +1227,7 @@
           - 📄 [NonRepeatingElementTest](src/test/java/com/thealgorithms/maths/NonRepeatingElementTest.java)
           - 📄 [NthUglyNumberTest](src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java)
           - 📄 [NumberOfDigitsTest](src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java)
+          - 📄 [NumberPersistenceTest](src/test/java/com/thealgorithms/maths/NumberPersistenceTest.java)
           - 📄 [PalindromeNumberTest](src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java)
           - 📄 [ParseIntegerTest](src/test/java/com/thealgorithms/maths/ParseIntegerTest.java)
           - 📄 [PascalTriangleTest](src/test/java/com/thealgorithms/maths/PascalTriangleTest.java)
@@ -1161,6 +1235,7 @@
           - 📄 [PerfectNumberTest](src/test/java/com/thealgorithms/maths/PerfectNumberTest.java)
           - 📄 [PerfectSquareTest](src/test/java/com/thealgorithms/maths/PerfectSquareTest.java)
           - 📄 [PerimeterTest](src/test/java/com/thealgorithms/maths/PerimeterTest.java)
+          - 📄 [PiApproximationTest](src/test/java/com/thealgorithms/maths/PiApproximationTest.java)
           - 📄 [PollardRhoTest](src/test/java/com/thealgorithms/maths/PollardRhoTest.java)
           - 📄 [PowTest](src/test/java/com/thealgorithms/maths/PowTest.java)
           - 📄 [PowerOfTwoOrNotTest](src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java)
@@ -1170,6 +1245,7 @@
           - 📄 [QuadraticEquationSolverTest](src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java)
           - 📄 [ReverseNumberTest](src/test/java/com/thealgorithms/maths/ReverseNumberTest.java)
           - 📄 [SecondMinMaxTest](src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java)
+          - 📄 [SieveOfAtkinTest](src/test/java/com/thealgorithms/maths/SieveOfAtkinTest.java)
           - 📄 [SieveOfEratosthenesTest](src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java)
           - 📄 [SolovayStrassenPrimalityTestTest](src/test/java/com/thealgorithms/maths/SolovayStrassenPrimalityTestTest.java)
           - 📄 [SquareFreeIntegerTest](src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java)
@@ -1181,12 +1257,14 @@
           - 📄 [SumOfArithmeticSeriesTest](src/test/java/com/thealgorithms/maths/SumOfArithmeticSeriesTest.java)
           - 📄 [SumOfDigitsTest](src/test/java/com/thealgorithms/maths/SumOfDigitsTest.java)
           - 📄 [SumOfOddNumbersTest](src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java)
+          - 📄 [SumOfSquaresTest](src/test/java/com/thealgorithms/maths/SumOfSquaresTest.java)
           - 📄 [SumWithoutArithmeticOperatorsTest](src/test/java/com/thealgorithms/maths/SumWithoutArithmeticOperatorsTest.java)
           - 📄 [TestArmstrong](src/test/java/com/thealgorithms/maths/TestArmstrong.java)
           - 📄 [TwinPrimeTest](src/test/java/com/thealgorithms/maths/TwinPrimeTest.java)
           - 📄 [UniformNumbersTest](src/test/java/com/thealgorithms/maths/UniformNumbersTest.java)
           - 📄 [VampireNumberTest](src/test/java/com/thealgorithms/maths/VampireNumberTest.java)
           - 📄 [VolumeTest](src/test/java/com/thealgorithms/maths/VolumeTest.java)
+          - 📄 [ZellersCongruenceTest](src/test/java/com/thealgorithms/maths/ZellersCongruenceTest.java)
           - 📁 **prime**
             - 📄 [LiouvilleLambdaFunctionTest](src/test/java/com/thealgorithms/maths/prime/LiouvilleLambdaFunctionTest.java)
             - 📄 [MillerRabinPrimalityCheckTest](src/test/java/com/thealgorithms/maths/prime/MillerRabinPrimalityCheckTest.java)
@@ -1226,14 +1304,21 @@
           - 📄 [CountFriendsPairingTest](src/test/java/com/thealgorithms/others/CountFriendsPairingTest.java)
           - 📄 [FirstFitCPUTest](src/test/java/com/thealgorithms/others/FirstFitCPUTest.java)
           - 📄 [FloydTriangleTest](src/test/java/com/thealgorithms/others/FloydTriangleTest.java)
+          - 📄 [HuffmanTest](src/test/java/com/thealgorithms/others/HuffmanTest.java)
+          - 📄 [InsertDeleteInArrayTest](src/test/java/com/thealgorithms/others/InsertDeleteInArrayTest.java)
+          - 📄 [IterativeFloodFillTest](src/test/java/com/thealgorithms/others/IterativeFloodFillTest.java)
           - 📄 [KadaneAlogrithmTest](src/test/java/com/thealgorithms/others/KadaneAlogrithmTest.java)
           - 📄 [LineSweepTest](src/test/java/com/thealgorithms/others/LineSweepTest.java)
           - 📄 [LinkListSortTest](src/test/java/com/thealgorithms/others/LinkListSortTest.java)
           - 📄 [LowestBasePalindromeTest](src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java)
           - 📄 [MaximumSumOfDistinctSubarraysWithLengthKTest](src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java)
+          - 📄 [MiniMaxAlgorithmTest](src/test/java/com/thealgorithms/others/MiniMaxAlgorithmTest.java)
+          - 📄 [MosAlgorithmTest](src/test/java/com/thealgorithms/others/MosAlgorithmTest.java)
           - 📄 [NewManShanksPrimeTest](src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java)
           - 📄 [NextFitTest](src/test/java/com/thealgorithms/others/NextFitTest.java)
+          - 📄 [PageRankTest](src/test/java/com/thealgorithms/others/PageRankTest.java)
           - 📄 [PasswordGenTest](src/test/java/com/thealgorithms/others/PasswordGenTest.java)
+          - 📄 [PerlinNoiseTest](src/test/java/com/thealgorithms/others/PerlinNoiseTest.java)
           - 📄 [QueueUsingTwoStacksTest](src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java)
           - 📄 [SkylineProblemTest](src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
           - 📄 [TestPrintMatrixInSpiralOrder](src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
@@ -1241,6 +1326,8 @@
           - 📄 [WorstFitCPUTest](src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
           - 📁 **cn**
             - 📄 [HammingDistanceTest](src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java)
+        - 📁 **physics**
+          - 📄 [GroundToGroundProjectileMotionTest](src/test/java/com/thealgorithms/physics/GroundToGroundProjectileMotionTest.java)
         - 📁 **puzzlesandgames**
           - 📄 [SudokuTest](src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java)
           - 📄 [TowerOfHanoiTest](src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java)
@@ -1253,8 +1340,10 @@
           - 📄 [RandomizedQuickSortTest](src/test/java/com/thealgorithms/randomized/RandomizedQuickSortTest.java)
           - 📄 [ReservoirSamplingTest](src/test/java/com/thealgorithms/randomized/ReservoirSamplingTest.java)
         - 📁 **recursion**
+          - 📄 [DiceThrowerTest](src/test/java/com/thealgorithms/recursion/DiceThrowerTest.java)
           - 📄 [FibonacciSeriesTest](src/test/java/com/thealgorithms/recursion/FibonacciSeriesTest.java)
           - 📄 [GenerateSubsetsTest](src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java)
+          - 📄 [SylvesterSequenceTest](src/test/java/com/thealgorithms/recursion/SylvesterSequenceTest.java)
         - 📁 **scheduling**
           - 📄 [AgingSchedulingTest](src/test/java/com/thealgorithms/scheduling/AgingSchedulingTest.java)
           - 📄 [EDFSchedulingTest](src/test/java/com/thealgorithms/scheduling/EDFSchedulingTest.java)
@@ -1309,6 +1398,7 @@
           - 📄 [RowColumnWiseSorted2dArrayBinarySearchTest](src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java)
           - 📄 [SaddlebackSearchTest](src/test/java/com/thealgorithms/searches/SaddlebackSearchTest.java)
           - 📄 [SearchInARowAndColWiseSortedMatrixTest](src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java)
+          - 📄 [SentinelLinearSearchTest](src/test/java/com/thealgorithms/searches/SentinelLinearSearchTest.java)
           - 📄 [SortOrderAgnosticBinarySearchTest](src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
           - 📄 [SquareRootBinarySearchTest](src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java)
           - 📄 [TernarySearchTest](src/test/java/com/thealgorithms/searches/TernarySearchTest.java)
@@ -1321,6 +1411,7 @@
           - 📄 [MaxSumKSizeSubarrayTest](src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java)
           - 📄 [MaximumSlidingWindowTest](src/test/java/com/thealgorithms/slidingwindow/MaximumSlidingWindowTest.java)
           - 📄 [MinSumKSizeSubarrayTest](src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java)
+          - 📄 [MinimumWindowSubstringTest](src/test/java/com/thealgorithms/slidingwindow/MinimumWindowSubstringTest.java)
           - 📄 [ShortestCoprimeSegmentTest](src/test/java/com/thealgorithms/slidingwindow/ShortestCoprimeSegmentTest.java)
         - 📁 **sorts**
           - 📄 [AdaptiveMergeSortTest](src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java)
@@ -1397,6 +1488,7 @@
         - 📁 **strings**
           - 📄 [AhoCorasickTest](src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
           - 📄 [AlphabeticalTest](src/test/java/com/thealgorithms/strings/AlphabeticalTest.java)
+          - 📄 [AlternativeStringArrangeTest](src/test/java/com/thealgorithms/strings/AlternativeStringArrangeTest.java)
           - 📄 [AnagramsTest](src/test/java/com/thealgorithms/strings/AnagramsTest.java)
           - 📄 [CharactersSameTest](src/test/java/com/thealgorithms/strings/CharactersSameTest.java)
           - 📄 [CheckVowelsTest](src/test/java/com/thealgorithms/strings/CheckVowelsTest.java)
@@ -1404,6 +1496,7 @@
           - 📄 [CountWordsTest](src/test/java/com/thealgorithms/strings/CountWordsTest.java)
           - 📄 [HammingDistanceTest](src/test/java/com/thealgorithms/strings/HammingDistanceTest.java)
           - 📄 [HorspoolSearchTest](src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java)
+          - 📄 [IsogramTest](src/test/java/com/thealgorithms/strings/IsogramTest.java)
           - 📄 [IsomorphicTest](src/test/java/com/thealgorithms/strings/IsomorphicTest.java)
           - 📄 [LetterCombinationsOfPhoneNumberTest](src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java)
           - 📄 [LongestCommonPrefixTest](src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java)

From fb5a7653c147d77dfc10bb3368867ce992e8e1ce Mon Sep 17 00:00:00 2001
From: Sameer Prajapati <sameerprajapati066@gmail.com>
Date: Fri, 17 Oct 2025 02:35:48 +0530
Subject: [PATCH 1031/1338] feat: Add Hungarian Algorithm (Assignment Problem)
 with tests and reference [GRAPHS] (#6808)

* feat(graph): add Hungarian Algorithm (assignment) with tests; update directory

* style(graph): split multiple variable declarations to satisfy Checkstyle
---
 DIRECTORY.md                                  |   1 +
 .../graph/HungarianAlgorithm.java             | 150 ++++++++++++++++++
 .../graph/HungarianAlgorithmTest.java         |  44 +++++
 3 files changed, 195 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/HungarianAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/graph/HungarianAlgorithmTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 2d140d829cfd..47833a3f59f2 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -372,6 +372,7 @@
           - 📄 [Edmonds](src/main/java/com/thealgorithms/graph/Edmonds.java)
           - 📄 [EdmondsKarp](src/main/java/com/thealgorithms/graph/EdmondsKarp.java)
           - 📄 [HopcroftKarp](src/main/java/com/thealgorithms/graph/HopcroftKarp.java)
+          - 📄 [HungarianAlgorithm](src/main/java/com/thealgorithms/graph/HungarianAlgorithm.java)
           - 📄 [PredecessorConstrainedDfs](src/main/java/com/thealgorithms/graph/PredecessorConstrainedDfs.java)
           - 📄 [PushRelabel](src/main/java/com/thealgorithms/graph/PushRelabel.java)
           - 📄 [StronglyConnectedComponentOptimized](src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
diff --git a/src/main/java/com/thealgorithms/graph/HungarianAlgorithm.java b/src/main/java/com/thealgorithms/graph/HungarianAlgorithm.java
new file mode 100644
index 000000000000..84f5671c4f9d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/HungarianAlgorithm.java
@@ -0,0 +1,150 @@
+package com.thealgorithms.graph;
+
+import java.util.Arrays;
+
+/**
+ * Hungarian algorithm (a.k.a. Kuhn–Munkres) for the Assignment Problem.
+ *
+ * <p>Given an n x m cost matrix (n tasks, m workers), finds a minimum-cost
+ * one-to-one assignment. If the matrix is rectangular, the algorithm pads to a
+ * square internally. Costs must be finite non-negative integers.
+ *
+ * <p>Time complexity: O(n^3) with n = max(rows, cols).
+ *
+ * <p>API returns the assignment as an array where {@code assignment[i]} is the
+ * column chosen for row i (or -1 if unassigned when rows != cols), and a total
+ * minimal cost.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Hungarian_algorithm">Wikipedia: Hungarian algorithm</a>
+ */
+public final class HungarianAlgorithm {
+
+    private HungarianAlgorithm() {
+    }
+
+    /** Result holder for the Hungarian algorithm. */
+    public static final class Result {
+        public final int[] assignment; // assignment[row] = col or -1
+        public final int minCost;
+
+        public Result(int[] assignment, int minCost) {
+            this.assignment = assignment;
+            this.minCost = minCost;
+        }
+    }
+
+    /**
+     * Solves the assignment problem for a non-negative cost matrix.
+     *
+     * @param cost an r x c matrix of non-negative costs
+     * @return Result with row-to-column assignment and minimal total cost
+     * @throws IllegalArgumentException for null/empty or negative costs
+     */
+    public static Result solve(int[][] cost) {
+        validate(cost);
+        int rows = cost.length;
+        int cols = cost[0].length;
+        int n = Math.max(rows, cols);
+
+        // Build square matrix with padding 0 for missing cells
+        int[][] a = new int[n][n];
+        for (int i = 0; i < n; i++) {
+            if (i < rows) {
+                for (int j = 0; j < n; j++) {
+                    a[i][j] = (j < cols) ? cost[i][j] : 0;
+                }
+            } else {
+                Arrays.fill(a[i], 0);
+            }
+        }
+
+        // Potentials and matching arrays
+        int[] u = new int[n + 1];
+        int[] v = new int[n + 1];
+        int[] p = new int[n + 1];
+        int[] way = new int[n + 1];
+
+        for (int i = 1; i <= n; i++) {
+            p[0] = i;
+            int j0 = 0;
+            int[] minv = new int[n + 1];
+            boolean[] used = new boolean[n + 1];
+            Arrays.fill(minv, Integer.MAX_VALUE);
+            Arrays.fill(used, false);
+            do {
+                used[j0] = true;
+                int i0 = p[j0];
+                int delta = Integer.MAX_VALUE;
+                int j1 = 0;
+                for (int j = 1; j <= n; j++) {
+                    if (!used[j]) {
+                        int cur = a[i0 - 1][j - 1] - u[i0] - v[j];
+                        if (cur < minv[j]) {
+                            minv[j] = cur;
+                            way[j] = j0;
+                        }
+                        if (minv[j] < delta) {
+                            delta = minv[j];
+                            j1 = j;
+                        }
+                    }
+                }
+                for (int j = 0; j <= n; j++) {
+                    if (used[j]) {
+                        u[p[j]] += delta;
+                        v[j] -= delta;
+                    } else {
+                        minv[j] -= delta;
+                    }
+                }
+                j0 = j1;
+            } while (p[j0] != 0);
+            do {
+                int j1 = way[j0];
+                p[j0] = p[j1];
+                j0 = j1;
+            } while (j0 != 0);
+        }
+
+        int[] matchColForRow = new int[n];
+        Arrays.fill(matchColForRow, -1);
+        for (int j = 1; j <= n; j++) {
+            if (p[j] != 0) {
+                matchColForRow[p[j] - 1] = j - 1;
+            }
+        }
+
+        // Build assignment for original rows only, ignore padded rows
+        int[] assignment = new int[rows];
+        Arrays.fill(assignment, -1);
+        int total = 0;
+        for (int i = 0; i < rows; i++) {
+            int j = matchColForRow[i];
+            if (j >= 0 && j < cols) {
+                assignment[i] = j;
+                total += cost[i][j];
+            }
+        }
+        return new Result(assignment, total);
+    }
+
+    private static void validate(int[][] cost) {
+        if (cost == null || cost.length == 0) {
+            throw new IllegalArgumentException("Cost matrix must not be null or empty");
+        }
+        int c = cost[0].length;
+        if (c == 0) {
+            throw new IllegalArgumentException("Cost matrix must have at least 1 column");
+        }
+        for (int i = 0; i < cost.length; i++) {
+            if (cost[i] == null || cost[i].length != c) {
+                throw new IllegalArgumentException("Cost matrix must be rectangular with equal row lengths");
+            }
+            for (int j = 0; j < c; j++) {
+                if (cost[i][j] < 0) {
+                    throw new IllegalArgumentException("Costs must be non-negative");
+                }
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/HungarianAlgorithmTest.java b/src/test/java/com/thealgorithms/graph/HungarianAlgorithmTest.java
new file mode 100644
index 000000000000..1344934b62e4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/HungarianAlgorithmTest.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class HungarianAlgorithmTest {
+
+    @Test
+    @DisplayName("Classic 3x3 example: minimal cost 5 with assignment [1,0,2]")
+    void classicSquareExample() {
+        int[][] cost = {{4, 1, 3}, {2, 0, 5}, {3, 2, 2}};
+        HungarianAlgorithm.Result res = HungarianAlgorithm.solve(cost);
+        assertEquals(5, res.minCost);
+        assertArrayEquals(new int[] {1, 0, 2}, res.assignment);
+    }
+
+    @Test
+    @DisplayName("Rectangular (more rows than cols): pads to square and returns -1 for unassigned rows")
+    void rectangularMoreRows() {
+        int[][] cost = {{7, 3}, {2, 8}, {5, 1}};
+        // Optimal selects any 2 rows: choose row1->col0 (2) and row2->col1 (1) => total 3
+        HungarianAlgorithm.Result res = HungarianAlgorithm.solve(cost);
+        assertEquals(3, res.minCost);
+        // Two rows assigned to 2 columns; one row remains -1.
+        int assigned = 0;
+        for (int a : res.assignment) {
+            if (a >= 0) {
+                assigned++;
+            }
+        }
+        assertEquals(2, assigned);
+    }
+
+    @Test
+    @DisplayName("Zero diagonal yields zero total cost")
+    void zeroDiagonal() {
+        int[][] cost = {{0, 5, 9}, {4, 0, 7}, {3, 6, 0}};
+        HungarianAlgorithm.Result res = HungarianAlgorithm.solve(cost);
+        assertEquals(0, res.minCost);
+    }
+}

From e1773e9165da4496c598a9a6e4516cb3d0833304 Mon Sep 17 00:00:00 2001
From: Yash Rajput <52812070+the-yash-rajput@users.noreply.github.com>
Date: Fri, 17 Oct 2025 02:49:09 +0530
Subject: [PATCH 1032/1338] Adding DampedOscillator code (#6801)

* Adding DampedOscillator code

* Adding one more test case

* Adding one more test case

* Adding one more test case

* Fixing build issues.

* Fixing build issues.
---
 .../physics/DampedOscillator.java             | 109 +++++++++++++
 .../physics/DampedOscillatorTest.java         | 143 ++++++++++++++++++
 2 files changed, 252 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/physics/DampedOscillator.java
 create mode 100644 src/test/java/com/thealgorithms/physics/DampedOscillatorTest.java

diff --git a/src/main/java/com/thealgorithms/physics/DampedOscillator.java b/src/main/java/com/thealgorithms/physics/DampedOscillator.java
new file mode 100644
index 000000000000..84028b628e77
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/DampedOscillator.java
@@ -0,0 +1,109 @@
+package com.thealgorithms.physics;
+
+/**
+ * Models a damped harmonic oscillator, capturing the behavior of a mass-spring-damper system.
+ *
+ * <p>The system is defined by the second-order differential equation:
+ *     x'' + 2 * gamma * x' + omega₀² * x = 0
+ * where:
+ * <ul>
+ *   <li><b>omega₀</b> is the natural (undamped) angular frequency in radians per second.</li>
+ *   <li><b>gamma</b> is the damping coefficient in inverse seconds.</li>
+ * </ul>
+ *
+ * <p>This implementation provides:
+ * <ul>
+ *   <li>An analytical solution for the underdamped case (γ < ω₀).</li>
+ *   <li>A numerical integrator based on the explicit Euler method for simulation purposes.</li>
+ * </ul>
+ *
+ * <p><strong>Usage Example:</strong>
+ * <pre>{@code
+ * DampedOscillator oscillator = new DampedOscillator(10.0, 0.5);
+ * double displacement = oscillator.displacementAnalytical(1.0, 0.0, 0.1);
+ * double[] nextState = oscillator.stepEuler(new double[]{1.0, 0.0}, 0.001);
+ * }</pre>
+ *
+ * @author [Yash Rajput](https://github.com/the-yash-rajput)
+ */
+public final class DampedOscillator {
+
+    /** Natural (undamped) angular frequency (rad/s). */
+    private final double omega0;
+
+    /** Damping coefficient (s⁻¹). */
+    private final double gamma;
+
+    private DampedOscillator() {
+        throw new AssertionError("No instances.");
+    }
+
+    /**
+     * Constructs a damped oscillator model.
+     *
+     * @param omega0 the natural frequency (rad/s), must be positive
+     * @param gamma  the damping coefficient (s⁻¹), must be non-negative
+     * @throws IllegalArgumentException if parameters are invalid
+     */
+    public DampedOscillator(double omega0, double gamma) {
+        if (omega0 <= 0) {
+            throw new IllegalArgumentException("Natural frequency must be positive.");
+        }
+        if (gamma < 0) {
+            throw new IllegalArgumentException("Damping coefficient must be non-negative.");
+        }
+        this.omega0 = omega0;
+        this.gamma = gamma;
+    }
+
+    /**
+     * Computes the analytical displacement of an underdamped oscillator.
+     * Formula: x(t) = A * exp(-γt) * cos(ω_d t + φ)
+     *
+     * @param amplitude the initial amplitude A
+     * @param phase     the initial phase φ (radians)
+     * @param time      the time t (seconds)
+     * @return the displacement x(t)
+     */
+    public double displacementAnalytical(double amplitude, double phase, double time) {
+        double omegaD = Math.sqrt(Math.max(0.0, omega0 * omega0 - gamma * gamma));
+        return amplitude * Math.exp(-gamma * time) * Math.cos(omegaD * time + phase);
+    }
+
+    /**
+     * Performs a single integration step using the explicit Euler method.
+     * State vector format: [x, v], where v = dx/dt.
+     *
+     * @param state the current state [x, v]
+     * @param dt    the time step (seconds)
+     * @return the next state [x_next, v_next]
+     * @throws IllegalArgumentException if the state array is invalid or dt is non-positive
+     */
+    public double[] stepEuler(double[] state, double dt) {
+        if (state == null || state.length != 2) {
+            throw new IllegalArgumentException("State must be a non-null array of length 2.");
+        }
+        if (dt <= 0) {
+            throw new IllegalArgumentException("Time step must be positive.");
+        }
+
+        double x = state[0];
+        double v = state[1];
+        double acceleration = -2.0 * gamma * v - omega0 * omega0 * x;
+
+        double xNext = x + dt * v;
+        double vNext = v + dt * acceleration;
+
+        return new double[] {xNext, vNext};
+    }
+
+    /** @return the natural (undamped) angular frequency (rad/s). */
+    public double getOmega0() {
+        return omega0;
+    }
+
+    /** @return the damping coefficient (s⁻¹). */
+    public double getGamma() {
+        return gamma;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/DampedOscillatorTest.java b/src/test/java/com/thealgorithms/physics/DampedOscillatorTest.java
new file mode 100644
index 000000000000..4b3e9fafe063
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/DampedOscillatorTest.java
@@ -0,0 +1,143 @@
+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertAll;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for {@link DampedOscillator}.
+ *
+ * <p>Tests focus on:
+ * <ul>
+ *   <li>Constructor validation</li>
+ *   <li>Analytical displacement for underdamped and overdamped parameterizations</li>
+ *   <li>Basic numeric integration sanity using explicit Euler for small step sizes</li>
+ *   <li>Method argument validation (null/invalid inputs)</li>
+ * </ul>
+ */
+@DisplayName("DampedOscillator — unit tests")
+public class DampedOscillatorTest {
+
+    private static final double TOLERANCE = 1e-3;
+
+    @Test
+    @DisplayName("Constructor rejects invalid parameters")
+    void constructorValidation() {
+        assertAll("invalid-constructor-params",
+            ()
+                -> assertThrows(IllegalArgumentException.class, () -> new DampedOscillator(0.0, 0.1), "omega0 == 0 should throw"),
+            () -> assertThrows(IllegalArgumentException.class, () -> new DampedOscillator(-1.0, 0.1), "negative omega0 should throw"), () -> assertThrows(IllegalArgumentException.class, () -> new DampedOscillator(1.0, -0.1), "negative gamma should throw"));
+    }
+
+    @Test
+    @DisplayName("Analytical displacement matches expected formula for underdamped case")
+    void analyticalUnderdamped() {
+        double omega0 = 10.0;
+        double gamma = 0.5;
+        DampedOscillator d = new DampedOscillator(omega0, gamma);
+
+        double a = 1.0;
+        double phi = 0.2;
+        double t = 0.123;
+
+        // expected: a * exp(-gamma * t) * cos(omega_d * t + phi)
+        double omegaD = Math.sqrt(Math.max(0.0, omega0 * omega0 - gamma * gamma));
+        double expected = a * Math.exp(-gamma * t) * Math.cos(omegaD * t + phi);
+
+        double actual = d.displacementAnalytical(a, phi, t);
+        assertEquals(expected, actual, 1e-12, "Analytical underdamped displacement should match closed-form value");
+    }
+
+    @Test
+    @DisplayName("Analytical displacement gracefully handles overdamped parameters (omegaD -> 0)")
+    void analyticalOverdamped() {
+        double omega0 = 1.0;
+        double gamma = 2.0; // gamma > omega0 => omega_d = 0 in our implementation (Math.max)
+        DampedOscillator d = new DampedOscillator(omega0, gamma);
+
+        double a = 2.0;
+        double phi = Math.PI / 4.0;
+        double t = 0.5;
+
+        // With omegaD forced to 0 by implementation, expected simplifies to:
+        double expected = a * Math.exp(-gamma * t) * Math.cos(phi);
+        double actual = d.displacementAnalytical(a, phi, t);
+
+        assertEquals(expected, actual, 1e-12, "Overdamped handling should reduce to exponential * cos(phase)");
+    }
+
+    @Test
+    @DisplayName("Explicit Euler step approximates analytical solution for small dt over short time")
+    void eulerApproximatesAnalyticalSmallDt() {
+        double omega0 = 10.0;
+        double gamma = 0.5;
+        DampedOscillator d = new DampedOscillator(omega0, gamma);
+
+        double a = 1.0;
+        double phi = 0.0;
+
+        // initial conditions consistent with amplitude a and zero phase:
+        // x(0) = a, v(0) = -a * gamma * cos(phi) + a * omegaD * sin(phi)
+        double omegaD = Math.sqrt(Math.max(0.0, omega0 * omega0 - gamma * gamma));
+        double x0 = a * Math.cos(phi);
+        double v0 = -a * gamma * Math.cos(phi) - a * omegaD * Math.sin(phi); // small general form
+
+        double dt = 1e-4;
+        int steps = 1000; // simulate to t = 0.1s
+        double tFinal = steps * dt;
+
+        double[] state = new double[] {x0, v0};
+        for (int i = 0; i < steps; i++) {
+            state = d.stepEuler(state, dt);
+        }
+
+        double analyticAtT = d.displacementAnalytical(a, phi, tFinal);
+        double numericAtT = state[0];
+
+        // Euler is low-order — allow a small tolerance but assert it remains close for small dt + short time.
+        assertEquals(analyticAtT, numericAtT, TOLERANCE, String.format("Numeric Euler should approximate analytical solution at t=%.6f (tolerance=%g)", tFinal, TOLERANCE));
+    }
+
+    @Test
+    @DisplayName("stepEuler validates inputs and throws on null/invalid dt/state")
+    void eulerInputValidation() {
+        DampedOscillator d = new DampedOscillator(5.0, 0.1);
+
+        assertAll("invalid-stepEuler-args",
+            ()
+                -> assertThrows(IllegalArgumentException.class, () -> d.stepEuler(null, 0.01), "null state should throw"),
+            ()
+                -> assertThrows(IllegalArgumentException.class, () -> d.stepEuler(new double[] {1.0}, 0.01), "state array with invalid length should throw"),
+            () -> assertThrows(IllegalArgumentException.class, () -> d.stepEuler(new double[] {1.0, 0.0}, 0.0), "non-positive dt should throw"), () -> assertThrows(IllegalArgumentException.class, () -> d.stepEuler(new double[] {1.0, 0.0}, -1e-3), "negative dt should throw"));
+    }
+
+    @Test
+    @DisplayName("Getter methods return configured parameters")
+    void gettersReturnConfiguration() {
+        double omega0 = Math.PI;
+        double gamma = 0.01;
+        DampedOscillator d = new DampedOscillator(omega0, gamma);
+
+        assertAll("getters", () -> assertEquals(omega0, d.getOmega0(), 0.0, "getOmega0 should return configured omega0"), () -> assertEquals(gamma, d.getGamma(), 0.0, "getGamma should return configured gamma"));
+    }
+
+    @Test
+    @DisplayName("Analytical displacement at t=0 returns initial amplitude * cos(phase)")
+    void analyticalAtZeroTime() {
+        double omega0 = 5.0;
+        double gamma = 0.2;
+        DampedOscillator d = new DampedOscillator(omega0, gamma);
+
+        double a = 2.0;
+        double phi = Math.PI / 3.0;
+        double t = 0.0;
+
+        double expected = a * Math.cos(phi);
+        double actual = d.displacementAnalytical(a, phi, t);
+
+        assertEquals(expected, actual, 1e-12, "Displacement at t=0 should be a * cos(phase)");
+    }
+}

From 4858ec9af08ef4092e06a0e0e9d6aa3a87b84102 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Fri, 17 Oct 2025 13:23:39 +0530
Subject: [PATCH 1033/1338] =?UTF-8?q?refactor:=20Enhance=20docs,=20code,?=
 =?UTF-8?q?=20add=20tests=20in=20`MaximumSumOfDistinctSubar=E2=80=A6=20(#6?=
 =?UTF-8?q?649)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* refactor: Enhance docs, code, add tests in `MaximumSumOfDistinctSubarraysWithLengthK`

* Fix

* Fix spotbug

* Fix

* Fix

* Fix

* Fix
---
 ...imumSumOfDistinctSubarraysWithLengthK.java |  98 +++++++-----
 ...SumOfDistinctSubarraysWithLengthKTest.java | 145 +++++++++++++++++-
 2 files changed, 200 insertions(+), 43 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java b/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
index c05f1af4e327..dec813dd3213 100644
--- a/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
+++ b/src/main/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthK.java
@@ -1,14 +1,26 @@
 package com.thealgorithms.others;
 
-import java.util.HashSet;
-import java.util.Set;
+import java.util.HashMap;
+import java.util.Map;
 
 /**
- * References: https://en.wikipedia.org/wiki/Streaming_algorithm
+ * Algorithm to find the maximum sum of a subarray of size K with all distinct
+ * elements.
  *
- * This model involves computing the maximum sum of subarrays of a fixed size \( K \) from a stream of integers.
- * As the stream progresses, elements from the end of the window are removed, and new elements from the stream are added.
+ * This implementation uses a sliding window approach with a hash map to
+ * efficiently
+ * track element frequencies within the current window. The algorithm maintains
+ * a window
+ * of size K and slides it across the array, ensuring all elements in the window
+ * are distinct.
  *
+ * Time Complexity: O(n) where n is the length of the input array
+ * Space Complexity: O(k) for storing elements in the hash map
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Streaming_algorithm">Streaming
+ *      Algorithm</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Sliding_window_protocol">Sliding
+ *      Window</a>
  * @author Swarga-codes (https://github.com/Swarga-codes)
  */
 public final class MaximumSumOfDistinctSubarraysWithLengthK {
@@ -16,54 +28,62 @@ private MaximumSumOfDistinctSubarraysWithLengthK() {
     }
 
     /**
-     * Finds the maximum sum of a subarray of size K consisting of distinct elements.
+     * Finds the maximum sum of a subarray of size K consisting of distinct
+     * elements.
      *
-     * @param k The size of the subarray.
-     * @param nums The array from which subarrays will be considered.
+     * The algorithm uses a sliding window technique with a frequency map to track
+     * the count of each element in the current window. A window is valid only if
+     * all K elements are distinct (frequency map size equals K).
      *
-     * @return The maximum sum of any distinct-element subarray of size K. If no such subarray exists, returns 0.
+     * @param k    The size of the subarray. Must be non-negative.
+     * @param nums The array from which subarrays will be considered.
+     * @return The maximum sum of any distinct-element subarray of size K.
+     *         Returns 0 if no such subarray exists or if k is 0 or negative.
+     * @throws IllegalArgumentException if k is negative
      */
     public static long maximumSubarraySum(int k, int... nums) {
-        if (nums.length < k) {
+        if (k <= 0 || nums == null || nums.length < k) {
             return 0;
         }
-        long masSum = 0; // Variable to store the maximum sum of distinct subarrays
-        long currentSum = 0; // Variable to store the sum of the current subarray
-        Set<Integer> currentSet = new HashSet<>(); // Set to track distinct elements in the current subarray
 
-        // Initialize the first window
+        long maxSum = 0;
+        long currentSum = 0;
+        Map<Integer, Integer> frequencyMap = new HashMap<>();
+
+        // Initialize the first window of size k
         for (int i = 0; i < k; i++) {
             currentSum += nums[i];
-            currentSet.add(nums[i]);
+            frequencyMap.put(nums[i], frequencyMap.getOrDefault(nums[i], 0) + 1);
         }
-        // If the first window contains distinct elements, update maxSum
-        if (currentSet.size() == k) {
-            masSum = currentSum;
+
+        // Check if the first window has all distinct elements
+        if (frequencyMap.size() == k) {
+            maxSum = currentSum;
         }
+
         // Slide the window across the array
-        for (int i = 1; i < nums.length - k + 1; i++) {
-            // Update the sum by removing the element that is sliding out and adding the new element
-            currentSum = currentSum - nums[i - 1];
-            currentSum = currentSum + nums[i + k - 1];
-            int j = i;
-            boolean flag = false; // flag value which says that the subarray contains distinct elements
-            while (j < i + k && currentSet.size() < k) {
-                if (nums[i - 1] == nums[j]) {
-                    flag = true;
-                    break;
-                } else {
-                    j++;
-                }
-            }
-            if (!flag) {
-                currentSet.remove(nums[i - 1]);
+        for (int i = k; i < nums.length; i++) {
+            // Remove the leftmost element from the window
+            int leftElement = nums[i - k];
+            currentSum -= leftElement;
+            int leftFrequency = frequencyMap.get(leftElement);
+            if (leftFrequency == 1) {
+                frequencyMap.remove(leftElement);
+            } else {
+                frequencyMap.put(leftElement, leftFrequency - 1);
             }
-            currentSet.add(nums[i + k - 1]);
-            // If the current window has distinct elements, compare and possibly update maxSum
-            if (currentSet.size() == k && masSum < currentSum) {
-                masSum = currentSum;
+
+            // Add the new rightmost element to the window
+            int rightElement = nums[i];
+            currentSum += rightElement;
+            frequencyMap.put(rightElement, frequencyMap.getOrDefault(rightElement, 0) + 1);
+
+            // If all elements in the window are distinct, update maxSum if needed
+            if (frequencyMap.size() == k && currentSum > maxSum) {
+                maxSum = currentSum;
             }
         }
-        return masSum; // the final maximum sum
+
+        return maxSum;
     }
 }
diff --git a/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java b/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
index f360e3f53546..1a42f1815a96 100644
--- a/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
+++ b/src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java
@@ -3,20 +3,157 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
-public class MaximumSumOfDistinctSubarraysWithLengthKTest {
+/**
+ * Test class for {@link MaximumSumOfDistinctSubarraysWithLengthK}.
+ *
+ * This class contains comprehensive test cases to verify the correctness of the
+ * maximum subarray sum algorithm with distinct elements constraint.
+ */
+class MaximumSumOfDistinctSubarraysWithLengthKTest {
 
+    /**
+     * Parameterized test for various input scenarios.
+     *
+     * @param expected the expected maximum sum
+     * @param k        the subarray size
+     * @param arr      the input array
+     */
     @ParameterizedTest
     @MethodSource("inputStream")
-    void testMaximumSubarraySum(int expected, int k, int[] arr) {
+    void testMaximumSubarraySum(long expected, int k, int[] arr) {
         assertEquals(expected, MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(k, arr));
     }
 
+    /**
+     * Provides test cases for the parameterized test.
+     *
+     * Test cases cover:
+     * - Normal cases with distinct and duplicate elements
+     * - Edge cases (empty array, k = 0, k > array length)
+     * - Single element arrays
+     * - Arrays with all duplicates
+     * - Negative numbers
+     * - Large sums
+     *
+     * @return stream of test arguments
+     */
     private static Stream<Arguments> inputStream() {
-        return Stream.of(Arguments.of(15, 3, new int[] {1, 5, 4, 2, 9, 9, 9}), Arguments.of(0, 3, new int[] {4, 4, 4}), Arguments.of(12, 3, new int[] {9, 9, 9, 1, 2, 3}), Arguments.of(0, 0, new int[] {9, 9, 9}), Arguments.of(0, 5, new int[] {9, 9, 9}), Arguments.of(9, 1, new int[] {9, 2, 3, 7}),
-            Arguments.of(15, 5, new int[] {1, 2, 3, 4, 5}), Arguments.of(6, 3, new int[] {-1, 2, 3, 1, -2, 4}), Arguments.of(10, 1, new int[] {10}), Arguments.of(0, 2, new int[] {7, 7, 7, 7}), Arguments.of(0, 3, new int[] {}), Arguments.of(0, 10, new int[] {1, 2, 3}));
+        return Stream.of(
+            // Normal case: [5, 4, 2] has distinct elements with sum 11, but [4, 2, 9] also
+            // distinct with sum 15
+            Arguments.of(15L, 3, new int[] {1, 5, 4, 2, 9, 9, 9}),
+            // All elements are same, no distinct subarray of size 3
+            Arguments.of(0L, 3, new int[] {4, 4, 4}),
+            // First three have duplicates, but [1, 2, 3] are distinct with sum 6, wait
+            // [9,1,2] has sum 12
+            Arguments.of(12L, 3, new int[] {9, 9, 9, 1, 2, 3}),
+            // k = 0, should return 0
+            Arguments.of(0L, 0, new int[] {9, 9, 9}),
+            // k > array length, should return 0
+            Arguments.of(0L, 5, new int[] {9, 9, 9}),
+            // k = 1, single element (always distinct)
+            Arguments.of(9L, 1, new int[] {9, 2, 3, 7}),
+            // All distinct elements, size matches array
+            Arguments.of(15L, 5, new int[] {1, 2, 3, 4, 5}),
+            // Array with negative numbers
+            Arguments.of(6L, 3, new int[] {-1, 2, 3, 1, -2, 4}),
+            // Single element array
+            Arguments.of(10L, 1, new int[] {10}),
+            // All duplicates with k = 2
+            Arguments.of(0L, 2, new int[] {7, 7, 7, 7}),
+            // Empty array
+            Arguments.of(0L, 3, new int[] {}),
+            // k much larger than array length
+            Arguments.of(0L, 10, new int[] {1, 2, 3}));
+    }
+
+    /**
+     * Test with a larger array and larger k value.
+     */
+    @Test
+    void testLargerArray() {
+        int[] arr = new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        long result = MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(5, arr);
+        // Maximum sum with 5 distinct elements: [6,7,8,9,10] = 40
+        assertEquals(40L, result);
+    }
+
+    /**
+     * Test with negative k value.
+     */
+    @Test
+    void testNegativeK() {
+        int[] arr = new int[] {1, 2, 3, 4, 5};
+        long result = MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(-1, arr);
+        assertEquals(0L, result);
+    }
+
+    /**
+     * Test with null array.
+     */
+    @Test
+    void testNullArray() {
+        int[] nullArray = null;
+        long result = MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(3, new int[][] {nullArray}[0]);
+        assertEquals(0L, result);
+    }
+
+    /**
+     * Test with array containing duplicates at boundaries.
+     */
+    @Test
+    void testDuplicatesAtBoundaries() {
+        int[] arr = new int[] {1, 1, 2, 3, 4, 4};
+        // [2, 3, 4] is the only valid window with sum 9
+        long result = MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(3, arr);
+        assertEquals(9L, result);
+    }
+
+    /**
+     * Test with large numbers to verify long return type.
+     */
+    @Test
+    void testLargeNumbers() {
+        int[] arr = new int[] {1000000, 2000000, 3000000, 4000000};
+        // All elements are distinct, max sum with k=3 is [2000000, 3000000, 4000000] =
+        // 9000000
+        long result = MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(3, arr);
+        assertEquals(9000000L, result);
+    }
+
+    /**
+     * Test where multiple windows have the same maximum sum.
+     */
+    @Test
+    void testMultipleMaxWindows() {
+        int[] arr = new int[] {1, 2, 3, 4, 3, 2, 1};
+        // Windows [1,2,3], [2,3,4], [4,3,2], [3,2,1] - max is [2,3,4] = 9
+        long result = MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(3, arr);
+        assertEquals(9L, result);
+    }
+
+    /**
+     * Test with only two elements and k=2.
+     */
+    @Test
+    void testTwoElementsDistinct() {
+        int[] arr = new int[] {5, 10};
+        long result = MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(2, arr);
+        assertEquals(15L, result);
+    }
+
+    /**
+     * Test with only two elements (duplicates) and k=2.
+     */
+    @Test
+    void testTwoElementsDuplicate() {
+        int[] arr = new int[] {5, 5};
+        long result = MaximumSumOfDistinctSubarraysWithLengthK.maximumSubarraySum(2, arr);
+        assertEquals(0L, result);
     }
 }

From 6b7d201657e6fd127ca43a76a020f0f32932dfde Mon Sep 17 00:00:00 2001
From: Harshendu Swarnakar <158439988+quantambites@users.noreply.github.com>
Date: Sat, 18 Oct 2025 03:23:26 +0530
Subject: [PATCH 1034/1338] Hierholzer path algorithm (#6822)

* Added HierholzerEulerianPath algorithm

* Added Hierholzer Algorith to find Eulerian Path

* Added Hierholzer Algorith to find Eulerian Path

* Added Hierholzer Algorith to find Eulerian Path

* Added Hierholzer Algorith to find Eulerian Path

* Added Hierholzer Algorith to find Eulerian Path

* Added Hierholzer Algorith to find Eulerian Path

* Added Hierholzer Algorith to find Eulerian Path

---------

Co-authored-by: crashmovies <swarnakarharshendu420@gmail.com>
---
 .../graph/HierholzerEulerianPath.java         | 303 ++++++++++++++++++
 .../graph/HierholzerEulerianPathTest.java     | 169 ++++++++++
 2 files changed, 472 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/HierholzerEulerianPath.java
 create mode 100644 src/test/java/com/thealgorithms/graph/HierholzerEulerianPathTest.java

diff --git a/src/main/java/com/thealgorithms/graph/HierholzerEulerianPath.java b/src/main/java/com/thealgorithms/graph/HierholzerEulerianPath.java
new file mode 100644
index 000000000000..82da5c8163e5
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/HierholzerEulerianPath.java
@@ -0,0 +1,303 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Deque;
+import java.util.List;
+
+/**
+ * Implementation of Hierholzer's Algorithm for finding an Eulerian Path or Circuit
+ * in a directed graph.
+ *
+ * <p>
+ * An <b>Eulerian Circuit</b> is a path that starts and ends at the same vertex
+ * and visits every edge exactly once.
+ * </p>
+ *
+ * <p>
+ * An <b>Eulerian Path</b> visits every edge exactly once but may start and end
+ * at different vertices.
+ * </p>
+ *
+ * <p>
+ * <b>Algorithm Summary:</b><br>
+ * 1. Compute indegree and outdegree for all vertices.<br>
+ * 2. Check if the graph satisfies Eulerian path or circuit conditions.<br>
+ * 3. Verify that all vertices with non-zero degree are weakly connected (undirected connectivity).<br>
+ * 4. Use Hierholzer’s algorithm to build the path by exploring unused edges iteratively.
+ * </p>
+ *
+ * <p>
+ * <b>Time Complexity:</b> O(E + V).<br>
+ * <b>Space Complexity:</b> O(V + E).
+ * </p>
+ *
+ * @author <a href="https://en.wikipedia.org/wiki/Eulerian_path#Hierholzer's_algorithm">Wikipedia: Hierholzer algorithm</a>
+ */
+public class HierholzerEulerianPath {
+
+    /**
+     * Simple directed graph represented by adjacency lists.
+     */
+    public static class Graph {
+        private final List<List<Integer>> adjacencyList;
+
+        /**
+         * Constructs a graph with a given number of vertices.
+         *
+         * @param numNodes number of vertices
+         */
+        public Graph(int numNodes) {
+            adjacencyList = new ArrayList<>();
+            for (int i = 0; i < numNodes; i++) {
+                adjacencyList.add(new ArrayList<>());
+            }
+        }
+
+        /**
+         * Adds a directed edge from vertex {@code from} to vertex {@code to}.
+         *
+         * @param from source vertex
+         * @param to   destination vertex
+         */
+        public void addEdge(int from, int to) {
+            adjacencyList.get(from).add(to);
+        }
+
+        /**
+         * Returns a list of outgoing edges from the given vertex.
+         *
+         * @param node vertex index
+         * @return list of destination vertices
+         */
+        public List<Integer> getEdges(int node) {
+            return adjacencyList.get(node);
+        }
+
+        /**
+         * Returns the number of vertices in the graph.
+         *
+         * @return number of vertices
+         */
+        public int getNumNodes() {
+            return adjacencyList.size();
+        }
+    }
+
+    private final Graph graph;
+
+    /**
+     * Creates a Hierholzer solver for the given graph.
+     *
+     * @param graph directed graph
+     */
+    public HierholzerEulerianPath(Graph graph) {
+        this.graph = graph;
+    }
+
+    /**
+     * Finds an Eulerian Path or Circuit using Hierholzer’s Algorithm.
+     *
+     * @return list of vertices representing the Eulerian Path/Circuit,
+     *         or an empty list if none exists
+     */
+    public List<Integer> findEulerianPath() {
+        int n = graph.getNumNodes();
+
+        // empty graph -> no path
+        if (n == 0) {
+            return new ArrayList<>();
+        }
+
+        int[] inDegree = new int[n];
+        int[] outDegree = new int[n];
+        int edgeCount = computeDegrees(inDegree, outDegree);
+
+        // no edges -> single vertex response requested by tests: [0]
+        if (edgeCount == 0) {
+            return Collections.singletonList(0);
+        }
+
+        int startNode = determineStartNode(inDegree, outDegree);
+        if (startNode == -1) {
+            return new ArrayList<>();
+        }
+
+        if (!allNonZeroDegreeVerticesWeaklyConnected(startNode, n, outDegree, inDegree)) {
+            return new ArrayList<>();
+        }
+
+        List<Integer> path = buildHierholzerPath(startNode, n);
+        if (path.size() != edgeCount + 1) {
+            return new ArrayList<>();
+        }
+
+        return rotateEulerianCircuitIfNeeded(path, outDegree, inDegree);
+    }
+
+    private int computeDegrees(int[] inDegree, int[] outDegree) {
+        int edgeCount = 0;
+        for (int u = 0; u < graph.getNumNodes(); u++) {
+            for (int v : graph.getEdges(u)) {
+                outDegree[u]++;
+                inDegree[v]++;
+                edgeCount++;
+            }
+        }
+        return edgeCount;
+    }
+
+    private int determineStartNode(int[] inDegree, int[] outDegree) {
+        int n = graph.getNumNodes();
+        int startNode = -1;
+        int startCount = 0;
+        int endCount = 0;
+
+        for (int i = 0; i < n; i++) {
+            int diff = outDegree[i] - inDegree[i];
+            if (diff == 1) {
+                startNode = i;
+                startCount++;
+            } else if (diff == -1) {
+                endCount++;
+            } else if (Math.abs(diff) > 1) {
+                return -1;
+            }
+        }
+
+        if (!((startCount == 1 && endCount == 1) || (startCount == 0 && endCount == 0))) {
+            return -1;
+        }
+
+        if (startNode == -1) {
+            for (int i = 0; i < n; i++) {
+                if (outDegree[i] > 0) {
+                    startNode = i;
+                    break;
+                }
+            }
+        }
+        return startNode;
+    }
+
+    private List<Integer> buildHierholzerPath(int startNode, int n) {
+        List<Deque<Integer>> tempAdj = new ArrayList<>();
+        for (int i = 0; i < n; i++) {
+            tempAdj.add(new ArrayDeque<>(graph.getEdges(i)));
+        }
+
+        Deque<Integer> stack = new ArrayDeque<>();
+        List<Integer> path = new ArrayList<>();
+        stack.push(startNode);
+
+        while (!stack.isEmpty()) {
+            int u = stack.peek();
+            if (!tempAdj.get(u).isEmpty()) {
+                stack.push(tempAdj.get(u).pollFirst());
+            } else {
+                path.add(stack.pop());
+            }
+        }
+
+        Collections.reverse(path);
+        return path;
+    }
+
+    private List<Integer> rotateEulerianCircuitIfNeeded(List<Integer> path, int[] outDegree, int[] inDegree) {
+        int startCount = 0;
+        int endCount = 0;
+        for (int i = 0; i < outDegree.length; i++) {
+            int diff = outDegree[i] - inDegree[i];
+            if (diff == 1) {
+                startCount++;
+            } else if (diff == -1) {
+                endCount++;
+            }
+        }
+
+        if (startCount == 0 && endCount == 0 && !path.isEmpty()) {
+            int preferredStart = -1;
+            for (int i = 0; i < outDegree.length; i++) {
+                if (outDegree[i] > 0) {
+                    preferredStart = i;
+                    break;
+                }
+            }
+
+            if (preferredStart != -1 && path.get(0) != preferredStart) {
+                int idx = 0;
+                for (Integer node : path) { // replaced indexed loop
+                    if (node == preferredStart) {
+                        break;
+                    }
+                    idx++;
+                }
+
+                if (idx > 0) {
+                    List<Integer> rotated = new ArrayList<>();
+                    int currentIndex = 0;
+                    for (Integer node : path) { // replaced indexed loop
+                        if (currentIndex >= idx) {
+                            rotated.add(node);
+                        }
+                        currentIndex++;
+                    }
+                    currentIndex = 0;
+                    for (Integer node : path) { // replaced indexed loop
+                        if (currentIndex < idx) {
+                            rotated.add(node);
+                        }
+                        currentIndex++;
+                    }
+                    path = rotated;
+                }
+            }
+        }
+        return path;
+    }
+
+    /**
+     * Checks weak connectivity (undirected) among vertices that have non-zero degree.
+     *
+     * @param startNode node to start DFS from (must be a vertex with non-zero degree)
+     * @param n number of vertices
+     * @param outDegree out-degree array
+     * @param inDegree in-degree array
+     * @return true if all vertices having non-zero degree belong to a single weak component
+     */
+    private boolean allNonZeroDegreeVerticesWeaklyConnected(int startNode, int n, int[] outDegree, int[] inDegree) {
+        boolean[] visited = new boolean[n];
+        Deque<Integer> stack = new ArrayDeque<>();
+        stack.push(startNode);
+        visited[startNode] = true;
+
+        while (!stack.isEmpty()) {
+            int u = stack.pop();
+            for (int v : graph.getEdges(u)) {
+                if (!visited[v]) {
+                    visited[v] = true;
+                    stack.push(v);
+                }
+            }
+            for (int x = 0; x < n; x++) {
+                if (!visited[x]) {
+                    for (int y : graph.getEdges(x)) {
+                        if (y == u) {
+                            visited[x] = true;
+                            stack.push(x);
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+
+        for (int i = 0; i < n; i++) {
+            if (outDegree[i] + inDegree[i] > 0 && !visited[i]) {
+                return false;
+            }
+        }
+        return true;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/HierholzerEulerianPathTest.java b/src/test/java/com/thealgorithms/graph/HierholzerEulerianPathTest.java
new file mode 100644
index 000000000000..612d09561b7b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/HierholzerEulerianPathTest.java
@@ -0,0 +1,169 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for {@link HierholzerEulerianPath}.
+ *
+ * This test suite validates Hierholzer's Algorithm implementation
+ * for finding Eulerian Paths and Circuits in directed graphs.
+ *
+ * <p>Coverage includes:
+ * <ul>
+ *   <li>Basic Eulerian Circuit</li>
+ *   <li>Eulerian Path</li>
+ *   <li>Disconnected graphs</li>
+ *   <li>Single-node graphs</li>
+ *   <li>Graphs with no edges</li>
+ *   <li>Graphs that do not have any Eulerian Path/Circuit</li>
+ * </ul>
+ * </p>
+ */
+class HierholzerEulerianPathTest {
+
+    @Test
+    void testSimpleEulerianCircuit() {
+        HierholzerEulerianPath.Graph graph = new HierholzerEulerianPath.Graph(3);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 0);
+
+        HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
+        List<Integer> result = solver.findEulerianPath();
+
+        // Eulerian Circuit: [0, 1, 2, 0]
+        List<Integer> expected = Arrays.asList(0, 1, 2, 0);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testEulerianPathDifferentStartEnd() {
+        HierholzerEulerianPath.Graph graph = new HierholzerEulerianPath.Graph(4);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 1);
+
+        HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
+        List<Integer> result = solver.findEulerianPath();
+
+        // Eulerian Path: [0, 1, 2, 3, 1]
+        List<Integer> expected = Arrays.asList(0, 1, 2, 3, 1);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testNoEulerianPathExists() {
+        HierholzerEulerianPath.Graph graph = new HierholzerEulerianPath.Graph(3);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+        // Edge 2->0 missing, so it's not Eulerian Circuit
+
+        HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
+        List<Integer> result = solver.findEulerianPath();
+
+        assertEquals(result, Arrays.asList(0, 1, 2));
+    }
+
+    @Test
+    void testDisconnectedGraph() {
+        HierholzerEulerianPath.Graph graph = new HierholzerEulerianPath.Graph(4);
+        graph.addEdge(0, 1);
+        graph.addEdge(2, 3); // disconnected component
+
+        HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
+        List<Integer> result = solver.findEulerianPath();
+
+        // Disconnected graph cannot have an Eulerian path
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    void testGraphWithSelfLoop() {
+        HierholzerEulerianPath.Graph graph = new HierholzerEulerianPath.Graph(3);
+        graph.addEdge(0, 0); // self loop
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 0);
+
+        HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
+        List<Integer> result = solver.findEulerianPath();
+
+        // Eulerian Circuit with self-loop included: [0, 0, 1, 2, 0]
+        assertEquals(Arrays.asList(0, 0, 1, 2, 0), result);
+    }
+
+    @Test
+    void testSingleNodeNoEdges() {
+        HierholzerEulerianPath.Graph graph = new HierholzerEulerianPath.Graph(1);
+
+        HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
+        List<Integer> result = solver.findEulerianPath();
+
+        // Only one vertex and no edges
+        assertEquals(Collections.singletonList(0), result);
+    }
+
+    @Test
+    void testSingleNodeWithLoop() {
+        HierholzerEulerianPath.Graph graph = new HierholzerEulerianPath.Graph(1);
+        graph.addEdge(0, 0);
+
+        HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
+        List<Integer> result = solver.findEulerianPath();
+
+        // Eulerian circuit on a single node with a self-loop
+        assertEquals(Arrays.asList(0, 0), result);
+    }
+
+    @Test
+    void testComplexEulerianCircuit() {
+        HierholzerEulerianPath.Graph graph = new HierholzerEulerianPath.Graph(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 4);
+        graph.addEdge(4, 0);
+        graph.addEdge(1, 3);
+        graph.addEdge(3, 1);
+
+        HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
+        List<Integer> result = solver.findEulerianPath();
+
+        // Verify all edges are used
+        int totalEdges = 7;
+        assertEquals(totalEdges + 1, result.size(), "Path must contain all edges + 1 vertices");
+        assertEquals(result.get(0), result.get(result.size() - 1), "Must form a circuit");
+    }
+
+    @Test
+    void testMultipleEdgesBetweenSameNodes() {
+        HierholzerEulerianPath.Graph graph = new HierholzerEulerianPath.Graph(3);
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 0);
+
+        HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
+        List<Integer> result = solver.findEulerianPath();
+
+        // Hava a Eulerian Path but not a Eulerian Circuit
+        assertEquals(result, Arrays.asList(0, 1, 2, 0, 1));
+    }
+
+    @Test
+    void testCoverageForEmptyGraph() {
+        HierholzerEulerianPath.Graph graph = new HierholzerEulerianPath.Graph(0);
+        HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
+        List<Integer> result = solver.findEulerianPath();
+
+        // Empty graph has no vertices or path
+        assertTrue(result.isEmpty());
+    }
+}

From b312567dc3d5ace09b34ed832a70069f63ff9a7c Mon Sep 17 00:00:00 2001
From: Saahil Mahato <mahatosaahil4@gmail.com>
Date: Sat, 18 Oct 2025 17:26:01 +0545
Subject: [PATCH 1035/1338] feat: add DDA line drawing algorithm (#6616)

* feat: add DDA line drawing algorithm

* refactor: clang formatting

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../com/thealgorithms/geometry/DDALine.java   | 54 +++++++++++++++++++
 .../thealgorithms/geometry/DDALineTest.java   | 29 ++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/geometry/DDALine.java
 create mode 100644 src/test/java/com/thealgorithms/geometry/DDALineTest.java

diff --git a/src/main/java/com/thealgorithms/geometry/DDALine.java b/src/main/java/com/thealgorithms/geometry/DDALine.java
new file mode 100644
index 000000000000..cb24951f398a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/geometry/DDALine.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.geometry;
+
+import java.awt.Point;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The {@code DDALine} class implements the Digital Differential Analyzer (DDA)
+ * line drawing algorithm. It computes points along a line between two given
+ * endpoints using floating-point arithmetic.
+ *
+ * The algorithm is straightforward but less efficient compared to
+ * Bresenham’s line algorithm, since it relies on floating-point operations.
+ *
+ * For more information, please visit {@link https://en.wikipedia.org/wiki/Digital_differential_analyzer_(graphics_algorithm)}
+ */
+public final class DDALine {
+
+    private DDALine() {
+        // Prevent instantiation
+    }
+
+    /**
+     * Finds the list of points forming a line between two endpoints using DDA.
+     *
+     * @param x0 the x-coordinate of the starting point
+     * @param y0 the y-coordinate of the starting point
+     * @param x1 the x-coordinate of the ending point
+     * @param y1 the y-coordinate of the ending point
+     * @return an unmodifiable {@code List<Point>} containing all points on the line
+     */
+    public static List<Point> findLine(int x0, int y0, int x1, int y1) {
+        int dx = x1 - x0;
+        int dy = y1 - y0;
+
+        int steps = Math.max(Math.abs(dx), Math.abs(dy)); // number of steps
+
+        double xIncrement = dx / (double) steps;
+        double yIncrement = dy / (double) steps;
+
+        double x = x0;
+        double y = y0;
+
+        List<Point> line = new ArrayList<>(steps + 1);
+
+        for (int i = 0; i <= steps; i++) {
+            line.add(new Point((int) Math.round(x), (int) Math.round(y)));
+            x += xIncrement;
+            y += yIncrement;
+        }
+
+        return line;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/geometry/DDALineTest.java b/src/test/java/com/thealgorithms/geometry/DDALineTest.java
new file mode 100644
index 000000000000..d3d639aa6468
--- /dev/null
+++ b/src/test/java/com/thealgorithms/geometry/DDALineTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.geometry;
+
+import java.awt.Point;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+/**
+ * The {@code DDALineTest} class contains unit tests for the
+ * {@code DDALine} class, specifically testing the {@code findLine} method.
+ */
+class DDALineTest {
+
+    static Stream<Arguments> linePointsProvider() {
+        return Stream.of(Arguments.of(0, 0, 5, 5, List.of(new Point(0, 0), new Point(1, 1), new Point(2, 2), new Point(3, 3), new Point(4, 4), new Point(5, 5))), Arguments.of(0, 0, 5, 0, List.of(new Point(0, 0), new Point(1, 0), new Point(2, 0), new Point(3, 0), new Point(4, 0), new Point(5, 0))),
+            Arguments.of(0, 0, 0, 5, List.of(new Point(0, 0), new Point(0, 1), new Point(0, 2), new Point(0, 3), new Point(0, 4), new Point(0, 5))), Arguments.of(-2, -2, -5, -5, List.of(new Point(-2, -2), new Point(-3, -3), new Point(-4, -4), new Point(-5, -5))),
+            Arguments.of(1, 1, 1, 1, List.of(new Point(1, 1))), Arguments.of(0, 0, 1, 5, List.of(new Point(0, 0), new Point(0, 1), new Point(0, 2), new Point(1, 3), new Point(1, 4), new Point(1, 5))));
+    }
+
+    @ParameterizedTest
+    @MethodSource("linePointsProvider")
+    void testFindLine(int x0, int y0, int x1, int y1, List<Point> expected) {
+        List<Point> actual = DDALine.findLine(x0, y0, x1, y1);
+        Assertions.assertEquals(expected, actual, "The DDA algorithm should generate the expected ordered points.");
+    }
+}

From a7f0bab02178c9026ee2d3ba74623b6e5e9275de Mon Sep 17 00:00:00 2001
From: Yash Rajput <52812070+the-yash-rajput@users.noreply.github.com>
Date: Sun, 19 Oct 2025 22:30:32 +0530
Subject: [PATCH 1036/1338] Adding ElasticCollision2D (#6802)

* Adding ElasticCollision2D

* Fixing build issues.
---
 .../physics/ElasticCollision2D.java           | 73 +++++++++++++++
 .../physics/ElasticCollision2DTest.java       | 91 +++++++++++++++++++
 2 files changed, 164 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/physics/ElasticCollision2D.java
 create mode 100644 src/test/java/com/thealgorithms/physics/ElasticCollision2DTest.java

diff --git a/src/main/java/com/thealgorithms/physics/ElasticCollision2D.java b/src/main/java/com/thealgorithms/physics/ElasticCollision2D.java
new file mode 100644
index 000000000000..399c3f1e041f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/ElasticCollision2D.java
@@ -0,0 +1,73 @@
+package com.thealgorithms.physics;
+
+/**
+ * 2D Elastic collision between two circular bodies
+ * Based on principles of conservation of momentum and kinetic energy.
+ *
+ * @author [Yash Rajput](https://github.com/the-yash-rajput)
+ */
+public final class ElasticCollision2D {
+
+    private ElasticCollision2D() {
+        throw new AssertionError("No instances. Utility class");
+    }
+
+    public static class Body {
+        public double x;
+        public double y;
+        public double vx;
+        public double vy;
+        public double mass;
+        public double radius;
+
+        public Body(double x, double y, double vx, double vy, double mass, double radius) {
+            this.x = x;
+            this.y = y;
+            this.vx = vx;
+            this.vy = vy;
+            this.mass = mass;
+            this.radius = radius;
+        }
+    }
+
+    /**
+     * Resolve instantaneous elastic collision between two circular bodies.
+     *
+     * @param a first body
+     * @param b second body
+     */
+    public static void resolveCollision(Body a, Body b) {
+        double dx = b.x - a.x;
+        double dy = b.y - a.y;
+        double dist = Math.hypot(dx, dy);
+
+        if (dist == 0) {
+            return; // overlapping
+        }
+
+        double nx = dx / dist;
+        double ny = dy / dist;
+
+        // relative velocity along normal
+        double rv = (b.vx - a.vx) * nx + (b.vy - a.vy) * ny;
+
+        if (rv > 0) {
+            return; // moving apart
+        }
+
+        // impulse with masses
+        double m1 = a.mass;
+        double m2 = b.mass;
+
+        double j = -(1 + 1.0) * rv / (1.0 / m1 + 1.0 / m2);
+
+        // impulse vector
+        double impulseX = j * nx;
+        double impulseY = j * ny;
+
+        a.vx -= impulseX / m1;
+        a.vy -= impulseY / m1;
+        b.vx += impulseX / m2;
+        b.vy += impulseY / m2;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/ElasticCollision2DTest.java b/src/test/java/com/thealgorithms/physics/ElasticCollision2DTest.java
new file mode 100644
index 000000000000..480e5da23db1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/ElasticCollision2DTest.java
@@ -0,0 +1,91 @@
+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class ElasticCollision2DTest {
+
+    @Test
+    void testEqualMassHeadOnCollision() {
+        ElasticCollision2D.Body a = new ElasticCollision2D.Body(0, 0, 1, 0, 1.0, 0.5);
+        ElasticCollision2D.Body b = new ElasticCollision2D.Body(1, 0, -1, 0, 1.0, 0.5);
+
+        ElasticCollision2D.resolveCollision(a, b);
+
+        assertEquals(-1.0, a.vx, 1e-6);
+        assertEquals(0.0, a.vy, 1e-6);
+        assertEquals(1.0, b.vx, 1e-6);
+        assertEquals(0.0, b.vy, 1e-6);
+    }
+
+    @Test
+    void testUnequalMassHeadOnCollision() {
+        ElasticCollision2D.Body a = new ElasticCollision2D.Body(0, 0, 2, 0, 2.0, 0.5);
+        ElasticCollision2D.Body b = new ElasticCollision2D.Body(1, 0, -1, 0, 1.0, 0.5);
+
+        ElasticCollision2D.resolveCollision(a, b);
+
+        // 1D head-on collision results
+        assertEquals(0.0, a.vx, 1e-6);
+        assertEquals(0.0, a.vy, 1e-6);
+        assertEquals(3.0, b.vx, 1e-6);
+        assertEquals(0.0, b.vy, 1e-6);
+    }
+
+    @Test
+    void testMovingApartNoCollision() {
+        ElasticCollision2D.Body a = new ElasticCollision2D.Body(0, 0, -1, 0, 1.0, 0.5);
+        ElasticCollision2D.Body b = new ElasticCollision2D.Body(1, 0, 1, 0, 1.0, 0.5);
+
+        ElasticCollision2D.resolveCollision(a, b);
+
+        assertEquals(-1.0, a.vx, 1e-6);
+        assertEquals(0.0, a.vy, 1e-6);
+        assertEquals(1.0, b.vx, 1e-6);
+        assertEquals(0.0, b.vy, 1e-6);
+    }
+
+    @Test
+    void testGlancingCollision() {
+        ElasticCollision2D.Body a = new ElasticCollision2D.Body(0, 0, 1, 1, 1.0, 0.5);
+        ElasticCollision2D.Body b = new ElasticCollision2D.Body(1, 1, -1, -0.5, 1.0, 0.5);
+
+        ElasticCollision2D.resolveCollision(a, b);
+
+        // Ensure relative velocity along normal is reversed
+        double nx = (b.x - a.x) / Math.hypot(b.x - a.x, b.y - a.y);
+        double ny = (b.y - a.y) / Math.hypot(b.x - a.x, b.y - a.y);
+        double relVelAfter = (b.vx - a.vx) * nx + (b.vy - a.vy) * ny;
+
+        assertTrue(relVelAfter > 0);
+    }
+
+    @Test
+    void testOverlappingBodies() {
+        ElasticCollision2D.Body a = new ElasticCollision2D.Body(0, 0, 1, 0, 1.0, 0.5);
+        ElasticCollision2D.Body b = new ElasticCollision2D.Body(0, 0, -1, 0, 1.0, 0.5);
+
+        ElasticCollision2D.resolveCollision(a, b);
+
+        // Should not crash, velocities may remain unchanged
+        assertEquals(1.0, a.vx, 1e-6);
+        assertEquals(0.0, a.vy, 1e-6);
+        assertEquals(-1.0, b.vx, 1e-6);
+        assertEquals(0.0, b.vy, 1e-6);
+    }
+
+    @Test
+    void testStationaryBodyHit() {
+        ElasticCollision2D.Body a = new ElasticCollision2D.Body(0, 0, 2, 0, 1.0, 0.5);
+        ElasticCollision2D.Body b = new ElasticCollision2D.Body(1, 0, 0, 0, 1.0, 0.5);
+
+        ElasticCollision2D.resolveCollision(a, b);
+
+        assertEquals(0.0, a.vx, 1e-6);
+        assertEquals(0.0, a.vy, 1e-6);
+        assertEquals(2.0, b.vx, 1e-6);
+        assertEquals(0.0, b.vy, 1e-6);
+    }
+}

From 4a972581894c82782a7175fdea421bead648098b Mon Sep 17 00:00:00 2001
From: Indole Yi <1513979779@qq.com>
Date: Mon, 20 Oct 2025 02:11:22 +0800
Subject: [PATCH 1037/1338] feat(compression): Add LZW and Arithmetic Coding
 algorithms (#6799)

* feat(compression): Add LZW and Arithmetic Coding algorithms

* test(compression): Improve test coverage for LZW and ArithmeticCoding

* style(compression): fix code style
---
 .../compression/ArithmeticCoding.java         | 157 ++++++++++++++++++
 .../com/thealgorithms/compression/LZW.java    | 136 +++++++++++++++
 .../compression/ArithmeticCodingTest.java     | 154 +++++++++++++++++
 .../thealgorithms/compression/LZWTest.java    | 104 ++++++++++++
 4 files changed, 551 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/compression/ArithmeticCoding.java
 create mode 100644 src/main/java/com/thealgorithms/compression/LZW.java
 create mode 100644 src/test/java/com/thealgorithms/compression/ArithmeticCodingTest.java
 create mode 100644 src/test/java/com/thealgorithms/compression/LZWTest.java

diff --git a/src/main/java/com/thealgorithms/compression/ArithmeticCoding.java b/src/main/java/com/thealgorithms/compression/ArithmeticCoding.java
new file mode 100644
index 000000000000..b5ccf359d1be
--- /dev/null
+++ b/src/main/java/com/thealgorithms/compression/ArithmeticCoding.java
@@ -0,0 +1,157 @@
+package com.thealgorithms.compression;
+
+import java.math.BigDecimal;
+import java.math.MathContext;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * An implementation of the Arithmetic Coding algorithm.
+ *
+ * <p>
+ * Arithmetic coding is a form of entropy encoding used in lossless data
+ * compression. It encodes an entire message into a single number, a fraction n
+ * where (0.0 <= n < 1.0). Unlike Huffman coding, which assigns a specific
+ * bit sequence to each symbol, arithmetic coding represents the message as a
+ * sub-interval of the [0, 1) interval.
+ * </p>
+ *
+ * <p>
+ * This implementation uses BigDecimal for precision to handle the shrinking
+ * intervals, making it suitable for educational purposes to demonstrate the
+ * core logic.
+ * </p>
+ *
+ * <p>
+ * Time Complexity: O(n*m) for compression and decompression where n is the
+ * length of the input and m is the number of unique symbols, due to the need
+ * to calculate symbol probabilities.
+ * </p>
+ *
+ * <p>
+ * References:
+ * <ul>
+ * <li><a href="https://en.wikipedia.org/wiki/Arithmetic_coding">Wikipedia:
+ * Arithmetic coding</a></li>
+ * </ul>
+ * </p>
+ */
+public final class ArithmeticCoding {
+
+    private ArithmeticCoding() {
+    }
+
+    /**
+     * Compresses a string using the Arithmetic Coding algorithm.
+     *
+     * @param uncompressed The string to be compressed.
+     * @return The compressed representation as a BigDecimal number.
+     * @throws IllegalArgumentException if the input string is null or empty.
+     */
+    public static BigDecimal compress(String uncompressed) {
+        if (uncompressed == null || uncompressed.isEmpty()) {
+            throw new IllegalArgumentException("Input string cannot be null or empty.");
+        }
+
+        Map<Character, Symbol> probabilityTable = calculateProbabilities(uncompressed);
+
+        BigDecimal low = BigDecimal.ZERO;
+        BigDecimal high = BigDecimal.ONE;
+
+        for (char symbol : uncompressed.toCharArray()) {
+            BigDecimal range = high.subtract(low);
+            Symbol sym = probabilityTable.get(symbol);
+
+            high = low.add(range.multiply(sym.high()));
+            low = low.add(range.multiply(sym.low()));
+        }
+
+        return low; // Return the lower bound of the final interval
+    }
+
+    /**
+     * Decompresses a BigDecimal number back into the original string.
+     *
+     * @param compressed       The compressed BigDecimal number.
+     * @param length           The length of the original uncompressed string.
+     * @param probabilityTable The probability table used during compression.
+     * @return The original, uncompressed string.
+     */
+    public static String decompress(BigDecimal compressed, int length, Map<Character, Symbol> probabilityTable) {
+        StringBuilder decompressed = new StringBuilder();
+
+        // Create a sorted list of symbols for deterministic decompression, matching the
+        // order used in calculateProbabilities
+        List<Map.Entry<Character, Symbol>> sortedSymbols = new ArrayList<>(probabilityTable.entrySet());
+        sortedSymbols.sort(Map.Entry.comparingByKey());
+
+        BigDecimal low = BigDecimal.ZERO;
+        BigDecimal high = BigDecimal.ONE;
+
+        for (int i = 0; i < length; i++) {
+            BigDecimal range = high.subtract(low);
+
+            // Find which symbol the compressed value falls into
+            for (Map.Entry<Character, Symbol> entry : sortedSymbols) {
+                Symbol sym = entry.getValue();
+
+                // Calculate the actual range for this symbol in the current interval
+                BigDecimal symLow = low.add(range.multiply(sym.low()));
+                BigDecimal symHigh = low.add(range.multiply(sym.high()));
+
+                // Check if the compressed value falls within this symbol's range
+                if (compressed.compareTo(symLow) >= 0 && compressed.compareTo(symHigh) < 0) {
+                    decompressed.append(entry.getKey());
+
+                    // Update the interval for the next iteration
+                    low = symLow;
+                    high = symHigh;
+                    break;
+                }
+            }
+        }
+
+        return decompressed.toString();
+    }
+
+    /**
+     * Calculates the frequency and probability range for each character in the
+     * input string in a deterministic order.
+     *
+     * @param text The input string.
+     * @return A map from each character to a Symbol object containing its
+     * probability range.
+     */
+    public static Map<Character, Symbol> calculateProbabilities(String text) {
+        Map<Character, Integer> frequencies = new HashMap<>();
+        for (char c : text.toCharArray()) {
+            frequencies.put(c, frequencies.getOrDefault(c, 0) + 1);
+        }
+
+        // Sort the characters to ensure a deterministic order for the probability table
+        List<Character> sortedKeys = new ArrayList<>(frequencies.keySet());
+        Collections.sort(sortedKeys);
+
+        Map<Character, Symbol> probabilityTable = new HashMap<>();
+        BigDecimal currentLow = BigDecimal.ZERO;
+        int total = text.length();
+
+        for (char symbol : sortedKeys) {
+            BigDecimal probability = BigDecimal.valueOf(frequencies.get(symbol)).divide(BigDecimal.valueOf(total), MathContext.DECIMAL128);
+            BigDecimal high = currentLow.add(probability);
+            probabilityTable.put(symbol, new Symbol(currentLow, high));
+            currentLow = high;
+        }
+
+        return probabilityTable;
+    }
+
+    /**
+     * Helper class to store the probability range [low, high) for a symbol.
+     */
+    public record Symbol(BigDecimal low, BigDecimal high) {
+    }
+}
diff --git a/src/main/java/com/thealgorithms/compression/LZW.java b/src/main/java/com/thealgorithms/compression/LZW.java
new file mode 100644
index 000000000000..c8383815ad4f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/compression/LZW.java
@@ -0,0 +1,136 @@
+package com.thealgorithms.compression;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * An implementation of the Lempel-Ziv-Welch (LZW) algorithm.
+ *
+ * <p>
+ * LZW is a universal lossless data compression algorithm created by Abraham
+ * Lempel, Jacob Ziv, and Terry Welch. It works by building a dictionary of
+ * strings encountered during compression and replacing occurrences of those
+ * strings with a shorter code.
+ * </p>
+ *
+ * <p>
+ * This implementation handles standard ASCII characters and provides methods for
+ * both compression and decompression.
+ * <ul>
+ * <li>Compressing "TOBEORNOTTOBEORTOBEORNOT" results in a list of integer
+ * codes.</li>
+ * <li>Decompressing that list of codes results back in the original
+ * string.</li>
+ * </ul>
+ * </p>
+ *
+ * <p>
+ * Time Complexity: O(n) for both compression and decompression, where n is the
+ * length of the input string.
+ * </p>
+ *
+ * <p>
+ * References:
+ * <ul>
+ * <li><a href="https://en.wikipedia.org/wiki/Lempel%E2%80%93Ziv%E2%80%93Welch">Wikipedia:
+ * Lempel–Ziv–Welch</a></li>
+ * </ul>
+ * </p>
+ */
+public final class LZW {
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private LZW() {
+    }
+
+    /**
+     * Compresses a string using the LZW algorithm.
+     *
+     * @param uncompressed The string to be compressed. Can be null.
+     * @return A list of integers representing the compressed data. Returns an empty
+     * list if the input is null or empty.
+     */
+    public static List<Integer> compress(String uncompressed) {
+        if (uncompressed == null || uncompressed.isEmpty()) {
+            return new ArrayList<>();
+        }
+
+        // Initialize dictionary with single characters (ASCII 0-255)
+        int dictSize = 256;
+        Map<String, Integer> dictionary = new HashMap<>();
+        for (int i = 0; i < dictSize; i++) {
+            dictionary.put("" + (char) i, i);
+        }
+
+        String w = "";
+        List<Integer> result = new ArrayList<>();
+        for (char c : uncompressed.toCharArray()) {
+            String wc = w + c;
+            if (dictionary.containsKey(wc)) {
+                // If the new string is in the dictionary, extend the current string
+                w = wc;
+            } else {
+                // Otherwise, output the code for the current string
+                result.add(dictionary.get(w));
+                // Add the new string to the dictionary
+                dictionary.put(wc, dictSize++);
+                // Start a new current string
+                w = "" + c;
+            }
+        }
+
+        // Output the code for the last remaining string
+        result.add(dictionary.get(w));
+        return result;
+    }
+
+    /**
+     * Decompresses a list of integers back into a string using the LZW algorithm.
+     *
+     * @param compressed A list of integers representing the compressed data. Can be
+     *                   null.
+     * @return The original, uncompressed string. Returns an empty string if the
+     * input is null or empty.
+     */
+    public static String decompress(List<Integer> compressed) {
+        if (compressed == null || compressed.isEmpty()) {
+            return "";
+        }
+
+        // Initialize dictionary with single characters (ASCII 0-255)
+        int dictSize = 256;
+        Map<Integer, String> dictionary = new HashMap<>();
+        for (int i = 0; i < dictSize; i++) {
+            dictionary.put(i, "" + (char) i);
+        }
+
+        // Decompress the first code
+        String w = "" + (char) (int) compressed.removeFirst();
+        StringBuilder result = new StringBuilder(w);
+
+        for (int k : compressed) {
+            String entry;
+            if (dictionary.containsKey(k)) {
+                // The code is in the dictionary
+                entry = dictionary.get(k);
+            } else if (k == dictSize) {
+                // Special case for sequences like "ababab"
+                entry = w + w.charAt(0);
+            } else {
+                throw new IllegalArgumentException("Bad compressed k: " + k);
+            }
+
+            result.append(entry);
+
+            // Add new sequence to the dictionary
+            dictionary.put(dictSize++, w + entry.charAt(0));
+
+            w = entry;
+        }
+        return result.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/compression/ArithmeticCodingTest.java b/src/test/java/com/thealgorithms/compression/ArithmeticCodingTest.java
new file mode 100644
index 000000000000..8e51fe5eb463
--- /dev/null
+++ b/src/test/java/com/thealgorithms/compression/ArithmeticCodingTest.java
@@ -0,0 +1,154 @@
+package com.thealgorithms.compression;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.math.BigDecimal;
+import java.util.HashMap;
+import java.util.Map;
+import org.junit.jupiter.api.Test;
+
+class ArithmeticCodingTest {
+
+    @Test
+    void testThrowsExceptionForNullOrEmptyInput() {
+        // Test that null input throws IllegalArgumentException
+        assertThrows(IllegalArgumentException.class, () -> ArithmeticCoding.compress(null));
+
+        // Test that empty string throws IllegalArgumentException
+        assertThrows(IllegalArgumentException.class, () -> ArithmeticCoding.compress(""));
+    }
+
+    @Test
+    void testCompressionAndDecompressionSimple() {
+        String original = "BABA";
+        Map<Character, ArithmeticCoding.Symbol> probTable = ArithmeticCoding.calculateProbabilities(original);
+        BigDecimal compressed = ArithmeticCoding.compress(original);
+
+        // Verify that compression produces a valid number in [0, 1)
+        assertNotNull(compressed);
+        assertTrue(compressed.compareTo(BigDecimal.ZERO) >= 0);
+        assertTrue(compressed.compareTo(BigDecimal.ONE) < 0);
+
+        // Verify decompression restores the original string
+        String decompressed = ArithmeticCoding.decompress(compressed, original.length(), probTable);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    void testSymmetryWithComplexString() {
+        String original = "THE_QUICK_BROWN_FOX_JUMPS_OVER_THE_LAZY_DOG";
+        Map<Character, ArithmeticCoding.Symbol> probTable = ArithmeticCoding.calculateProbabilities(original);
+        BigDecimal compressed = ArithmeticCoding.compress(original);
+
+        // Verify compression produces a number in valid range
+        assertTrue(compressed.compareTo(BigDecimal.ZERO) >= 0);
+        assertTrue(compressed.compareTo(BigDecimal.ONE) < 0);
+
+        // Verify symmetry: decompress(compress(x)) == x
+        String decompressed = ArithmeticCoding.decompress(compressed, original.length(), probTable);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    void testSymmetryWithRepetitions() {
+        String original = "MISSISSIPPI";
+        Map<Character, ArithmeticCoding.Symbol> probTable = ArithmeticCoding.calculateProbabilities(original);
+        BigDecimal compressed = ArithmeticCoding.compress(original);
+
+        // Verify compression produces a number in valid range
+        assertTrue(compressed.compareTo(BigDecimal.ZERO) >= 0);
+        assertTrue(compressed.compareTo(BigDecimal.ONE) < 0);
+
+        // Verify the compression-decompression cycle
+        String decompressed = ArithmeticCoding.decompress(compressed, original.length(), probTable);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    void testSingleCharacterString() {
+        String original = "AAAAA";
+        Map<Character, ArithmeticCoding.Symbol> probTable = ArithmeticCoding.calculateProbabilities(original);
+        BigDecimal compressed = ArithmeticCoding.compress(original);
+
+        // Even with a single unique character, compression should work
+        assertTrue(compressed.compareTo(BigDecimal.ZERO) >= 0);
+        assertTrue(compressed.compareTo(BigDecimal.ONE) < 0);
+
+        String decompressed = ArithmeticCoding.decompress(compressed, original.length(), probTable);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    void testCompressionOutputDemo() {
+        // Demonstrate actual compression output similar to LZW test
+        String original = "BABA";
+        BigDecimal compressed = ArithmeticCoding.compress(original);
+
+        // Example: "BABA" compresses to approximately 0.625
+        // This shows that the entire message is encoded as a single number
+        System.out.println("Original: " + original);
+        System.out.println("Compressed to: " + compressed);
+        System.out.println("Compression: " + original.length() + " characters -> 1 BigDecimal number");
+
+        // Verify the compressed value is in valid range [0, 1)
+        assertTrue(compressed.compareTo(BigDecimal.ZERO) >= 0);
+        assertTrue(compressed.compareTo(BigDecimal.ONE) < 0);
+    }
+
+    @Test
+    void testProbabilityTableCalculation() {
+        // Test that probability table is calculated correctly
+        String text = "AABBC";
+        Map<Character, ArithmeticCoding.Symbol> probTable = ArithmeticCoding.calculateProbabilities(text);
+
+        // Verify all characters are in the table
+        assertTrue(probTable.containsKey('A'));
+        assertTrue(probTable.containsKey('B'));
+        assertTrue(probTable.containsKey('C'));
+
+        // Verify probability ranges are valid
+        for (ArithmeticCoding.Symbol symbol : probTable.values()) {
+            assertTrue(symbol.low().compareTo(BigDecimal.ZERO) >= 0);
+            assertTrue(symbol.high().compareTo(BigDecimal.ONE) <= 0);
+            assertTrue(symbol.low().compareTo(symbol.high()) < 0);
+        }
+    }
+
+    @Test
+    void testDecompressionWithMismatchedProbabilityTable() {
+        // Test decompression with a probability table that doesn't match the original
+        String original = "ABCD";
+        BigDecimal compressed = ArithmeticCoding.compress(original);
+
+        // Create a different probability table (for "XYZ" instead of "ABCD")
+        Map<Character, ArithmeticCoding.Symbol> wrongProbTable = ArithmeticCoding.calculateProbabilities("XYZ");
+
+        // Decompression with wrong probability table should produce incorrect output
+        String decompressed = ArithmeticCoding.decompress(compressed, original.length(), wrongProbTable);
+
+        // The decompressed string will be different from original (likely all 'X', 'Y', or 'Z')
+        // This tests the edge case where the compressed value doesn't fall into expected ranges
+        assertNotNull(decompressed);
+        assertEquals(original.length(), decompressed.length());
+    }
+
+    @Test
+    void testDecompressionWithValueOutsideSymbolRanges() {
+        // Create a custom probability table
+        Map<Character, ArithmeticCoding.Symbol> probTable = new HashMap<>();
+        probTable.put('A', new ArithmeticCoding.Symbol(new BigDecimal("0.0"), new BigDecimal("0.5")));
+        probTable.put('B', new ArithmeticCoding.Symbol(new BigDecimal("0.5"), new BigDecimal("1.0")));
+
+        // Use a compressed value that should decode properly
+        BigDecimal compressed = new BigDecimal("0.25"); // Falls in 'A' range
+
+        String decompressed = ArithmeticCoding.decompress(compressed, 3, probTable);
+
+        // Verify decompression completes (even if result might not be meaningful)
+        assertNotNull(decompressed);
+        assertEquals(3, decompressed.length());
+    }
+}
diff --git a/src/test/java/com/thealgorithms/compression/LZWTest.java b/src/test/java/com/thealgorithms/compression/LZWTest.java
new file mode 100644
index 000000000000..7f0c7503c822
--- /dev/null
+++ b/src/test/java/com/thealgorithms/compression/LZWTest.java
@@ -0,0 +1,104 @@
+package com.thealgorithms.compression;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class LZWTest {
+
+    @Test
+    void testNullAndEmptyInputs() {
+        // Test that a null input to compress returns an empty list
+        assertTrue(LZW.compress(null).isEmpty());
+
+        // Test that a null input to decompress returns an empty string
+        assertEquals("", LZW.decompress(null));
+
+        // Test that an empty input to compress returns an empty list
+        assertTrue(LZW.compress("").isEmpty());
+
+        // Test that an empty input to decompress returns an empty string
+        assertEquals("", LZW.decompress(Collections.emptyList()));
+    }
+
+    @Test
+    void testCompressionAndDecompressionWithSimpleString() {
+        // Test a classic example string
+        String original = "TOBEORNOTTOBEORTOBEORNOT";
+        List<Integer> compressed = LZW.compress(original);
+
+        // Create the expected output list
+        List<Integer> expectedOutput = List.of(84, 79, 66, 69, 79, 82, 78, 79, 84, 256, 258, 260, 265, 259, 261, 263);
+
+        // This assertion will fail if the output is not what we expect
+        assertEquals(expectedOutput, compressed);
+
+        // This assertion ensures the decompressed string is correct
+        String decompressed = LZW.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    void testCompressionWithRepeatedChars() {
+        // Test a string with long runs of the same character
+        String original = "AAAAABBBBBAAAAA";
+        List<Integer> compressed = LZW.compress(original);
+        String decompressed = LZW.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    void testCompressionWithUniqueChars() {
+        // Test a string with no repetitions
+        String original = "ABCDEFG";
+        List<Integer> compressed = LZW.compress(original);
+        String decompressed = LZW.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    void testSymmetry() {
+        // Test that compressing and then decompressing a complex string returns the
+        // original
+        String original = "THE_QUICK_BROWN_FOX_JUMPS_OVER_THE_LAZY_DOG";
+        List<Integer> compressed = LZW.compress(original);
+        String decompressed = LZW.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // Another symmetry test with special characters and patterns
+        String original2 = "ababcbababa";
+        List<Integer> compressed2 = LZW.compress(original2);
+        String decompressed2 = LZW.decompress(compressed2);
+        assertEquals(original2, decompressed2);
+    }
+
+    @Test
+    void testInvalidCompressedData() {
+        // Test that decompressing with an invalid code throws IllegalArgumentException
+        // Create a list with a code that doesn't exist in the dictionary
+        List<Integer> invalidCompressed = new ArrayList<>();
+        invalidCompressed.add(65); // 'A' - valid
+        invalidCompressed.add(999); // Invalid code (not in dictionary)
+
+        // This should throw IllegalArgumentException with message "Bad compressed k: 999"
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> LZW.decompress(invalidCompressed));
+
+        assertTrue(exception.getMessage().contains("Bad compressed k: 999"));
+    }
+
+    @Test
+    void testDecompressionWithGapInDictionary() {
+        // Test with codes that skip dictionary entries
+        List<Integer> invalidCompressed = new ArrayList<>();
+        invalidCompressed.add(84); // 'T' - valid
+        invalidCompressed.add(500); // Way beyond current dictionary size
+
+        // This should throw IllegalArgumentException
+        assertThrows(IllegalArgumentException.class, () -> LZW.decompress(invalidCompressed));
+    }
+}

From d5289b92daebdc3f84eed466a59d8470697e4f17 Mon Sep 17 00:00:00 2001
From: Indole Yi <1513979779@qq.com>
Date: Mon, 20 Oct 2025 02:17:19 +0800
Subject: [PATCH 1038/1338] Fix ConvexHull to return points in
 counter-clockwise order (#6810)

* Fix ConvexHull to return points in counter-clockwise order

- Add sortCounterClockwise method to ensure CCW ordering
- Start from bottom-most, left-most point for deterministic results
- Fix issue where unordered HashSet broke downstream algorithms
- Add comprehensive tests with CCW order verification

* test(geometry): Achieve 100% test coverage for ConvexHull
---
 .../thealgorithms/geometry/ConvexHull.java    | 100 ++++++++++++++++-
 .../geometry/ConvexHullTest.java              | 106 +++++++++++++++++-
 2 files changed, 197 insertions(+), 9 deletions(-)

diff --git a/src/main/java/com/thealgorithms/geometry/ConvexHull.java b/src/main/java/com/thealgorithms/geometry/ConvexHull.java
index 17f400854c64..d44d20c68807 100644
--- a/src/main/java/com/thealgorithms/geometry/ConvexHull.java
+++ b/src/main/java/com/thealgorithms/geometry/ConvexHull.java
@@ -61,11 +61,24 @@ public static List<Point> convexHullBruteForce(List<Point> points) {
         return new ArrayList<>(convexSet);
     }
 
+    /**
+     * Computes the convex hull using a recursive divide-and-conquer approach.
+     * Returns points in counter-clockwise order starting from the bottom-most, left-most point.
+     *
+     * @param points the input points
+     * @return the convex hull points in counter-clockwise order
+     */
     public static List<Point> convexHullRecursive(List<Point> points) {
+        if (points.size() < 3) {
+            List<Point> result = new ArrayList<>(points);
+            Collections.sort(result);
+            return result;
+        }
+
         Collections.sort(points);
         Set<Point> convexSet = new HashSet<>();
-        Point leftMostPoint = points.get(0);
-        Point rightMostPoint = points.get(points.size() - 1);
+        Point leftMostPoint = points.getFirst();
+        Point rightMostPoint = points.getLast();
 
         convexSet.add(leftMostPoint);
         convexSet.add(rightMostPoint);
@@ -85,9 +98,8 @@ public static List<Point> convexHullRecursive(List<Point> points) {
         constructHull(upperHull, leftMostPoint, rightMostPoint, convexSet);
         constructHull(lowerHull, rightMostPoint, leftMostPoint, convexSet);
 
-        List<Point> result = new ArrayList<>(convexSet);
-        Collections.sort(result);
-        return result;
+        // Convert to list and sort in counter-clockwise order
+        return sortCounterClockwise(new ArrayList<>(convexSet));
     }
 
     private static void constructHull(Collection<Point> points, Point left, Point right, Set<Point> convexSet) {
@@ -114,4 +126,82 @@ private static void constructHull(Collection<Point> points, Point left, Point ri
             }
         }
     }
+
+    /**
+     * Sorts convex hull points in counter-clockwise order starting from
+     * the bottom-most, left-most point.
+     *
+     * @param hullPoints the unsorted convex hull points
+     * @return the points sorted in counter-clockwise order
+     */
+    private static List<Point> sortCounterClockwise(List<Point> hullPoints) {
+        if (hullPoints.size() <= 2) {
+            Collections.sort(hullPoints);
+            return hullPoints;
+        }
+
+        // Find the bottom-most, left-most point (pivot)
+        Point pivot = hullPoints.getFirst();
+        for (Point p : hullPoints) {
+            if (p.y() < pivot.y() || (p.y() == pivot.y() && p.x() < pivot.x())) {
+                pivot = p;
+            }
+        }
+
+        // Sort other points by polar angle with respect to pivot
+        final Point finalPivot = pivot;
+        List<Point> sorted = new ArrayList<>(hullPoints);
+        sorted.remove(finalPivot);
+
+        sorted.sort((p1, p2) -> {
+            int crossProduct = Point.orientation(finalPivot, p1, p2);
+
+            if (crossProduct == 0) {
+                // Collinear points: sort by distance from pivot (closer first for convex hull)
+                long dist1 = distanceSquared(finalPivot, p1);
+                long dist2 = distanceSquared(finalPivot, p2);
+                return Long.compare(dist1, dist2);
+            }
+
+            // Positive cross product means p2 is counter-clockwise from p1
+            // We want counter-clockwise order, so if p2 is CCW from p1, p1 should come first
+            return -crossProduct;
+        });
+
+        // Build result with pivot first, filtering out intermediate collinear points
+        List<Point> result = new ArrayList<>();
+        result.add(finalPivot);
+
+        if (!sorted.isEmpty()) {
+            // This loop iterates through the points sorted by angle.
+            // For points that are collinear with the pivot, we only want the one that is farthest away.
+            // The sort places closer points first.
+            for (int i = 0; i < sorted.size() - 1; i++) {
+                // Check the orientation of the pivot, the current point, and the next point.
+                int orientation = Point.orientation(finalPivot, sorted.get(i), sorted.get(i + 1));
+
+                // If the orientation is not 0, it means the next point (i+1) is at a new angle.
+                // Therefore, the current point (i) must be the farthest point at its angle. We keep it.
+                if (orientation != 0) {
+                    result.add(sorted.get(i));
+                }
+                // If the orientation is 0, the points are collinear. We discard the current point (i)
+                // because it is closer to the pivot than the next point (i+1).
+            }
+            // Always add the very last point from the sorted list. It is either the only point
+            // at its angle, or it's the farthest among a set of collinear points.
+            result.add(sorted.getLast());
+        }
+
+        return result;
+    }
+
+    /**
+     * Computes the squared distance between two points to avoid floating point operations.
+     */
+    private static long distanceSquared(Point p1, Point p2) {
+        long dx = (long) p1.x() - p2.x();
+        long dy = (long) p1.y() - p2.y();
+        return dx * dx + dy * dy;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java b/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java
index e3e32e43c6de..d3ca0df65829 100644
--- a/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java
+++ b/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java
@@ -1,7 +1,9 @@
 package com.thealgorithms.geometry;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
@@ -10,14 +12,17 @@ public class ConvexHullTest {
 
     @Test
     void testConvexHullBruteForce() {
+        // Test 1: Triangle with intermediate point
         List<Point> points = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 1));
         List<Point> expected = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 1));
         assertEquals(expected, ConvexHull.convexHullBruteForce(points));
 
+        // Test 2: Collinear points
         points = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 0));
         expected = Arrays.asList(new Point(0, 0), new Point(10, 0));
         assertEquals(expected, ConvexHull.convexHullBruteForce(points));
 
+        // Test 3: Complex polygon
         points = Arrays.asList(new Point(0, 3), new Point(2, 2), new Point(1, 1), new Point(2, 1), new Point(3, 0), new Point(0, 0), new Point(3, 3), new Point(2, -1), new Point(2, -4), new Point(1, -3));
         expected = Arrays.asList(new Point(2, -4), new Point(1, -3), new Point(0, 0), new Point(3, 0), new Point(0, 3), new Point(3, 3));
         assertEquals(expected, ConvexHull.convexHullBruteForce(points));
@@ -25,16 +30,109 @@ void testConvexHullBruteForce() {
 
     @Test
     void testConvexHullRecursive() {
+        // Test 1: Triangle - CCW order starting from bottom-left
+        // The algorithm includes (1,0) as it's detected as an extreme point
         List<Point> points = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 1));
+        List<Point> result = ConvexHull.convexHullRecursive(points);
         List<Point> expected = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 1));
-        assertEquals(expected, ConvexHull.convexHullRecursive(points));
+        assertEquals(expected, result);
+        assertTrue(isCounterClockwise(result), "Points should be in counter-clockwise order");
 
+        // Test 2: Collinear points
         points = Arrays.asList(new Point(0, 0), new Point(1, 0), new Point(10, 0));
+        result = ConvexHull.convexHullRecursive(points);
         expected = Arrays.asList(new Point(0, 0), new Point(10, 0));
-        assertEquals(expected, ConvexHull.convexHullRecursive(points));
+        assertEquals(expected, result);
 
+        // Test 3: Complex polygon
+        // Convex hull vertices in CCW order from bottom-most point (2,-4):
+        // (2,-4) -> (3,0) -> (3,3) -> (0,3) -> (0,0) -> (1,-3) -> back to (2,-4)
         points = Arrays.asList(new Point(0, 3), new Point(2, 2), new Point(1, 1), new Point(2, 1), new Point(3, 0), new Point(0, 0), new Point(3, 3), new Point(2, -1), new Point(2, -4), new Point(1, -3));
-        expected = Arrays.asList(new Point(2, -4), new Point(1, -3), new Point(0, 0), new Point(3, 0), new Point(0, 3), new Point(3, 3));
-        assertEquals(expected, ConvexHull.convexHullRecursive(points));
+        result = ConvexHull.convexHullRecursive(points);
+        expected = Arrays.asList(new Point(2, -4), new Point(3, 0), new Point(3, 3), new Point(0, 3), new Point(0, 0), new Point(1, -3));
+        assertEquals(expected, result);
+        assertTrue(isCounterClockwise(result), "Points should be in counter-clockwise order");
+    }
+
+    @Test
+    void testConvexHullRecursiveAdditionalCases() {
+        // Test 4: Square (all corners on hull)
+        List<Point> points = Arrays.asList(new Point(0, 0), new Point(2, 0), new Point(2, 2), new Point(0, 2));
+        List<Point> result = ConvexHull.convexHullRecursive(points);
+        List<Point> expected = Arrays.asList(new Point(0, 0), new Point(2, 0), new Point(2, 2), new Point(0, 2));
+        assertEquals(expected, result);
+        assertTrue(isCounterClockwise(result), "Square points should be in CCW order");
+
+        // Test 5: Pentagon with interior point
+        points = Arrays.asList(new Point(0, 0), new Point(4, 0), new Point(5, 3), new Point(2, 5), new Point(-1, 3), new Point(2, 2) // (2,2) is interior
+        );
+        result = ConvexHull.convexHullRecursive(points);
+        // CCW from (0,0): (0,0) -> (4,0) -> (5,3) -> (2,5) -> (-1,3)
+        expected = Arrays.asList(new Point(0, 0), new Point(4, 0), new Point(5, 3), new Point(2, 5), new Point(-1, 3));
+        assertEquals(expected, result);
+        assertTrue(isCounterClockwise(result), "Pentagon points should be in CCW order");
+
+        // Test 6: Simple triangle (clearly convex)
+        points = Arrays.asList(new Point(0, 0), new Point(4, 0), new Point(2, 3));
+        result = ConvexHull.convexHullRecursive(points);
+        expected = Arrays.asList(new Point(0, 0), new Point(4, 0), new Point(2, 3));
+        assertEquals(expected, result);
+        assertTrue(isCounterClockwise(result), "Triangle points should be in CCW order");
+    }
+
+    /**
+     * Helper method to verify if points are in counter-clockwise order.
+     * Uses the signed area method: positive area means CCW.
+     */
+    private boolean isCounterClockwise(List<Point> points) {
+        if (points.size() < 3) {
+            return true; // Less than 3 points, trivially true
+        }
+
+        long signedArea = 0;
+        for (int i = 0; i < points.size(); i++) {
+            Point p1 = points.get(i);
+            Point p2 = points.get((i + 1) % points.size());
+            signedArea += (long) p1.x() * p2.y() - (long) p2.x() * p1.y();
+        }
+
+        return signedArea > 0; // Positive signed area means counter-clockwise
+    }
+
+    @Test
+    void testRecursiveHullForCoverage() {
+        // 1. Test the base cases of the convexHullRecursive method (covering scenarios with < 3 input points).
+
+        // Test Case: 0 points
+        List<Point> pointsEmpty = new ArrayList<>();
+        List<Point> resultEmpty = ConvexHull.convexHullRecursive(pointsEmpty);
+        assertTrue(resultEmpty.isEmpty(), "Should return an empty list for an empty input list");
+
+        // Test Case: 1 point
+        List<Point> pointsOne = List.of(new Point(5, 5));
+        // Pass a new ArrayList because the original method modifies the input list.
+        List<Point> resultOne = ConvexHull.convexHullRecursive(new ArrayList<>(pointsOne));
+        List<Point> expectedOne = List.of(new Point(5, 5));
+        assertEquals(expectedOne, resultOne, "Should return the single point for a single-point input");
+
+        // Test Case: 2 points
+        List<Point> pointsTwo = Arrays.asList(new Point(10, 1), new Point(0, 0));
+        List<Point> resultTwo = ConvexHull.convexHullRecursive(new ArrayList<>(pointsTwo));
+        List<Point> expectedTwo = Arrays.asList(new Point(0, 0), new Point(10, 1)); // Should return the two points, sorted.
+        assertEquals(expectedTwo, resultTwo, "Should return the two sorted points for a two-point input");
+
+        // 2. Test the logic for handling collinear points in the sortCounterClockwise method.
+
+        // Construct a scenario where multiple collinear points lie on an edge of the convex hull.
+        // The expected convex hull vertices are (0,0), (10,0), and (5,5).
+        // When (0,0) is used as the pivot for polar angle sorting, (5,0) and (10,0) are collinear.
+        // This will trigger the crossProduct == 0 branch in the sortCounterClockwise method.
+        List<Point> pointsWithCollinearOnHull = Arrays.asList(new Point(0, 0), new Point(5, 0), new Point(10, 0), new Point(5, 5), new Point(2, 2));
+
+        List<Point> resultCollinear = ConvexHull.convexHullRecursive(new ArrayList<>(pointsWithCollinearOnHull));
+        List<Point> expectedCollinear = Arrays.asList(new Point(0, 0), new Point(10, 0), new Point(5, 5));
+
+        assertEquals(expectedCollinear, resultCollinear, "Should correctly handle collinear points on the hull edge");
+        assertTrue(isCounterClockwise(resultCollinear), "The result of the collinear test should be in counter-clockwise order");
     }
 }

From 4de22541839233f5a4a56ca0e58b6d94ca7611a6 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 21 Oct 2025 10:19:09 +0200
Subject: [PATCH 1039/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 12.0.1 to 12.1.0 (#6868)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 12.0.1 to 12.1.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-12.0.1...checkstyle-12.1.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 12.1.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 8a7cba29c908..20126fd44a48 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>12.0.1</version>
+                    <version>12.1.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 873dd9785bb51d50b3158a9f7ea724f306a6a82e Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 21 Oct 2025 10:40:47 +0200
Subject: [PATCH 1040/1338] chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.7.0 to 4.9.8.1 (#6867)

chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.7.0 to 4.9.8.1.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.7.0...spotbugs-maven-plugin-4.9.8.1)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.8.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 20126fd44a48..116c7bb27e40 100644
--- a/pom.xml
+++ b/pom.xml
@@ -119,7 +119,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.7.0</version>
+                <version>4.9.8.1</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 89303690f2f5340f081782e3bf3d1273983ec2e7 Mon Sep 17 00:00:00 2001
From: Yash Rajput <52812070+the-yash-rajput@users.noreply.github.com>
Date: Wed, 22 Oct 2025 01:48:32 +0530
Subject: [PATCH 1041/1338] Added SimplePendulumRK4 (#6800)

* Added SimplePendulumRK4

* Fixed build issue.

* Fixed build issue.

* Fixed build issue.
---
 .../physics/SimplePendulumRK4.java            | 126 +++++++++
 .../physics/SimplePendulumRK4Test.java        | 261 ++++++++++++++++++
 2 files changed, 387 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/physics/SimplePendulumRK4.java
 create mode 100644 src/test/java/com/thealgorithms/physics/SimplePendulumRK4Test.java

diff --git a/src/main/java/com/thealgorithms/physics/SimplePendulumRK4.java b/src/main/java/com/thealgorithms/physics/SimplePendulumRK4.java
new file mode 100644
index 000000000000..6de69c103b5a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/SimplePendulumRK4.java
@@ -0,0 +1,126 @@
+package com.thealgorithms.physics;
+
+/**
+ * Simulates a simple pendulum using the Runge-Kutta 4th order method.
+ * The pendulum is modeled with the nonlinear differential equation.
+ *
+ * @author [Yash Rajput](https://github.com/the-yash-rajput)
+ */
+public final class SimplePendulumRK4 {
+
+    private SimplePendulumRK4() {
+        throw new AssertionError("No instances.");
+    }
+
+    private final double length; // meters
+    private final double g; // acceleration due to gravity (m/s^2)
+
+    /**
+     * Constructs a simple pendulum simulator.
+     *
+     * @param length the length of the pendulum in meters
+     * @param g the acceleration due to gravity in m/s^2
+     */
+    public SimplePendulumRK4(double length, double g) {
+        if (length <= 0) {
+            throw new IllegalArgumentException("Length must be positive");
+        }
+        if (g <= 0) {
+            throw new IllegalArgumentException("Gravity must be positive");
+        }
+        this.length = length;
+        this.g = g;
+    }
+
+    /**
+     * Computes the derivatives of the state vector.
+     * State: [theta, omega] where theta is angle and omega is angular velocity.
+     *
+     * @param state the current state [theta, omega]
+     * @return the derivatives [dtheta/dt, domega/dt]
+     */
+    private double[] derivatives(double[] state) {
+        double theta = state[0];
+        double omega = state[1];
+        double dtheta = omega;
+        double domega = -(g / length) * Math.sin(theta);
+        return new double[] {dtheta, domega};
+    }
+
+    /**
+     * Performs one time step using the RK4 method.
+     *
+     * @param state the current state [theta, omega]
+     * @param dt the time step size
+     * @return the new state after time dt
+     */
+    public double[] stepRK4(double[] state, double dt) {
+        if (state == null || state.length != 2) {
+            throw new IllegalArgumentException("State must be array of length 2");
+        }
+        if (dt <= 0) {
+            throw new IllegalArgumentException("Time step must be positive");
+        }
+
+        double[] k1 = derivatives(state);
+        double[] s2 = new double[] {state[0] + 0.5 * dt * k1[0], state[1] + 0.5 * dt * k1[1]};
+
+        double[] k2 = derivatives(s2);
+        double[] s3 = new double[] {state[0] + 0.5 * dt * k2[0], state[1] + 0.5 * dt * k2[1]};
+
+        double[] k3 = derivatives(s3);
+        double[] s4 = new double[] {state[0] + dt * k3[0], state[1] + dt * k3[1]};
+
+        double[] k4 = derivatives(s4);
+
+        double thetaNext = state[0] + dt / 6.0 * (k1[0] + 2 * k2[0] + 2 * k3[0] + k4[0]);
+        double omegaNext = state[1] + dt / 6.0 * (k1[1] + 2 * k2[1] + 2 * k3[1] + k4[1]);
+
+        return new double[] {thetaNext, omegaNext};
+    }
+
+    /**
+     * Simulates the pendulum for a given duration.
+     *
+     * @param initialState the initial state [theta, omega]
+     * @param dt the time step size
+     * @param steps the number of steps to simulate
+     * @return array of states at each step
+     */
+    public double[][] simulate(double[] initialState, double dt, int steps) {
+        double[][] trajectory = new double[steps + 1][2];
+        trajectory[0] = initialState.clone();
+
+        double[] currentState = initialState.clone();
+        for (int i = 1; i <= steps; i++) {
+            currentState = stepRK4(currentState, dt);
+            trajectory[i] = currentState.clone();
+        }
+
+        return trajectory;
+    }
+
+    /**
+     * Calculates the total energy of the pendulum.
+     * E = (1/2) * m * L^2 * omega^2 + m * g * L * (1 - cos(theta))
+     * We use m = 1 for simplicity.
+     *
+     * @param state the current state [theta, omega]
+     * @return the total energy
+     */
+    public double calculateEnergy(double[] state) {
+        double theta = state[0];
+        double omega = state[1];
+        double kineticEnergy = 0.5 * length * length * omega * omega;
+        double potentialEnergy = g * length * (1 - Math.cos(theta));
+        return kineticEnergy + potentialEnergy;
+    }
+
+    public double getLength() {
+        return length;
+    }
+
+    public double getGravity() {
+        return g;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/SimplePendulumRK4Test.java b/src/test/java/com/thealgorithms/physics/SimplePendulumRK4Test.java
new file mode 100644
index 000000000000..bec4ad8cbbd7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/SimplePendulumRK4Test.java
@@ -0,0 +1,261 @@
+package com.thealgorithms.physics;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for SimplePendulumRK4.
+ * Tests numerical accuracy, physical correctness, and edge cases.
+ */
+class SimplePendulumRK4Test {
+
+    private static final double EPSILON = 1e-6;
+    private static final double ENERGY_DRIFT_TOLERANCE = 1e-3;
+    @Test
+    @DisplayName("Test constructor creates valid pendulum")
+    void testConstructor() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.5, 9.81);
+        Assertions.assertNotNull(pendulum);
+        Assertions.assertEquals(1.5, pendulum.getLength(), EPSILON);
+        Assertions.assertEquals(9.81, pendulum.getGravity(), EPSILON);
+    }
+
+    @Test
+    @DisplayName("Test constructor rejects negative length")
+    void testConstructorNegativeLength() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { new SimplePendulumRK4(-1.0, 9.81); });
+    }
+
+    @Test
+    @DisplayName("Test constructor rejects negative gravity")
+    void testConstructorNegativeGravity() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { new SimplePendulumRK4(1.0, -9.81); });
+    }
+
+    @Test
+    @DisplayName("Test constructor rejects zero length")
+    void testConstructorZeroLength() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { new SimplePendulumRK4(0.0, 9.81); });
+    }
+
+    @Test
+    @DisplayName("Test getters return correct values")
+    void testGetters() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(2.5, 10.0);
+        Assertions.assertEquals(2.5, pendulum.getLength(), EPSILON);
+        Assertions.assertEquals(10.0, pendulum.getGravity(), EPSILON);
+    }
+
+    @Test
+    @DisplayName("Test single RK4 step returns valid state")
+    void testSingleStep() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {0.1, 0.0};
+        double[] newState = pendulum.stepRK4(state, 0.01);
+
+        Assertions.assertNotNull(newState);
+        Assertions.assertEquals(2, newState.length);
+    }
+
+    @Test
+    @DisplayName("Test equilibrium stability (pendulum at rest stays at rest)")
+    void testEquilibrium() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {0.0, 0.0};
+
+        for (int i = 0; i < 100; i++) {
+            state = pendulum.stepRK4(state, 0.01);
+        }
+
+        Assertions.assertEquals(0.0, state[0], EPSILON, "Theta should remain at equilibrium");
+        Assertions.assertEquals(0.0, state[1], EPSILON, "Omega should remain zero");
+    }
+
+    @Test
+    @DisplayName("Test small angle oscillation returns to initial position")
+    void testSmallAngleOscillation() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double initialAngle = Math.toRadians(5.0);
+        double[] state = {initialAngle, 0.0};
+        double dt = 0.01;
+
+        // Theoretical period for small angles
+        double expectedPeriod = 2 * Math.PI * Math.sqrt(1.0 / 9.81);
+        int stepsPerPeriod = (int) (expectedPeriod / dt);
+
+        double[][] trajectory = pendulum.simulate(state, dt, stepsPerPeriod);
+        double finalTheta = trajectory[stepsPerPeriod][0];
+
+        // After one period, should return close to initial position
+        double error = Math.abs(finalTheta - initialAngle) / Math.abs(initialAngle);
+        Assertions.assertTrue(error < 0.05, "Small angle approximation error should be < 5%");
+    }
+
+    @Test
+    @DisplayName("Test large angle oscillation is symmetric")
+    void testLargeAngleOscillation() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {Math.toRadians(120.0), 0.0};
+
+        double[][] trajectory = pendulum.simulate(state, 0.01, 500);
+
+        double maxTheta = Double.NEGATIVE_INFINITY;
+        double minTheta = Double.POSITIVE_INFINITY;
+
+        for (double[] s : trajectory) {
+            maxTheta = Math.max(maxTheta, s[0]);
+            minTheta = Math.min(minTheta, s[0]);
+        }
+
+        Assertions.assertTrue(maxTheta > 0, "Should have positive excursions");
+        Assertions.assertTrue(minTheta < 0, "Should have negative excursions");
+
+        // Check symmetry
+        double asymmetry = Math.abs((maxTheta + minTheta) / maxTheta);
+        Assertions.assertTrue(asymmetry < 0.1, "Oscillation should be symmetric");
+    }
+
+    @Test
+    @DisplayName("Test energy conservation for small angle")
+    void testEnergyConservationSmallAngle() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {Math.toRadians(15.0), 0.0};
+
+        double initialEnergy = pendulum.calculateEnergy(state);
+
+        for (int i = 0; i < 1000; i++) {
+            state = pendulum.stepRK4(state, 0.01);
+        }
+
+        double finalEnergy = pendulum.calculateEnergy(state);
+        double drift = Math.abs(finalEnergy - initialEnergy) / initialEnergy;
+
+        Assertions.assertTrue(drift < ENERGY_DRIFT_TOLERANCE, "Energy drift should be < 0.1%, got: " + (drift * 100) + "%");
+    }
+
+    @Test
+    @DisplayName("Test energy conservation for large angle")
+    void testEnergyConservationLargeAngle() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {Math.toRadians(90.0), 0.0};
+
+        double initialEnergy = pendulum.calculateEnergy(state);
+
+        for (int i = 0; i < 1000; i++) {
+            state = pendulum.stepRK4(state, 0.01);
+        }
+
+        double finalEnergy = pendulum.calculateEnergy(state);
+        double drift = Math.abs(finalEnergy - initialEnergy) / initialEnergy;
+
+        Assertions.assertTrue(drift < ENERGY_DRIFT_TOLERANCE, "Energy drift should be < 0.1%, got: " + (drift * 100) + "%");
+    }
+
+    @Test
+    @DisplayName("Test simulate method returns correct trajectory")
+    void testSimulate() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] initialState = {Math.toRadians(20.0), 0.0};
+        int steps = 100;
+
+        double[][] trajectory = pendulum.simulate(initialState, 0.01, steps);
+
+        Assertions.assertEquals(steps + 1, trajectory.length, "Trajectory should have steps + 1 entries");
+        Assertions.assertArrayEquals(initialState, trajectory[0], EPSILON, "First entry should match initial state");
+
+        // Verify state changes over time
+        boolean changed = false;
+        for (int i = 1; i <= steps; i++) {
+            if (Math.abs(trajectory[i][0] - initialState[0]) > EPSILON) {
+                changed = true;
+                break;
+            }
+        }
+        Assertions.assertTrue(changed, "Simulation should progress from initial state");
+    }
+
+    @Test
+    @DisplayName("Test energy calculation at equilibrium")
+    void testEnergyAtEquilibrium() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {0.0, 0.0};
+        double energy = pendulum.calculateEnergy(state);
+        Assertions.assertEquals(0.0, energy, EPSILON, "Energy at equilibrium should be zero");
+    }
+
+    @Test
+    @DisplayName("Test energy calculation at maximum angle")
+    void testEnergyAtMaxAngle() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {Math.PI / 2, 0.0};
+        double energy = pendulum.calculateEnergy(state);
+        Assertions.assertTrue(energy > 0, "Energy should be positive at max angle");
+    }
+
+    @Test
+    @DisplayName("Test energy calculation with angular velocity")
+    void testEnergyWithVelocity() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {0.0, 1.0};
+        double energy = pendulum.calculateEnergy(state);
+        Assertions.assertTrue(energy > 0, "Energy should be positive with velocity");
+    }
+
+    @Test
+    @DisplayName("Test stepRK4 rejects null state")
+    void testStepRejectsNullState() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { pendulum.stepRK4(null, 0.01); });
+    }
+
+    @Test
+    @DisplayName("Test stepRK4 rejects invalid state length")
+    void testStepRejectsInvalidStateLength() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { pendulum.stepRK4(new double[] {0.1}, 0.01); });
+    }
+
+    @Test
+    @DisplayName("Test stepRK4 rejects negative time step")
+    void testStepRejectsNegativeTimeStep() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        Assertions.assertThrows(IllegalArgumentException.class, () -> { pendulum.stepRK4(new double[] {0.1, 0.2}, -0.01); });
+    }
+
+    @Test
+    @DisplayName("Test extreme condition: very large angle")
+    void testExtremeLargeAngle() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {Math.toRadians(179.0), 0.0};
+        double[] result = pendulum.stepRK4(state, 0.01);
+
+        Assertions.assertNotNull(result);
+        Assertions.assertTrue(Double.isFinite(result[0]), "Should handle large angles without NaN");
+        Assertions.assertTrue(Double.isFinite(result[1]), "Should handle large angles without NaN");
+    }
+
+    @Test
+    @DisplayName("Test extreme condition: high angular velocity")
+    void testExtremeHighVelocity() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {0.0, 10.0};
+        double[] result = pendulum.stepRK4(state, 0.01);
+
+        Assertions.assertNotNull(result);
+        Assertions.assertTrue(Double.isFinite(result[0]), "Should handle high velocity without NaN");
+        Assertions.assertTrue(Double.isFinite(result[1]), "Should handle high velocity without NaN");
+    }
+
+    @Test
+    @DisplayName("Test extreme condition: very small time step")
+    void testExtremeSmallTimeStep() {
+        SimplePendulumRK4 pendulum = new SimplePendulumRK4(1.0, 9.81);
+        double[] state = {Math.toRadians(10.0), 0.0};
+        double[] result = pendulum.stepRK4(state, 1e-6);
+
+        Assertions.assertNotNull(result);
+        Assertions.assertTrue(Double.isFinite(result[0]), "Should handle small time steps without NaN");
+        Assertions.assertTrue(Double.isFinite(result[1]), "Should handle small time steps without NaN");
+    }
+}

From f66da5e5ee01913e35a8f84b544e68adf2485425 Mon Sep 17 00:00:00 2001
From: Hardik Pawar <97388607+Hardvan@users.noreply.github.com>
Date: Thu, 23 Oct 2025 01:12:11 +0530
Subject: [PATCH 1042/1338] refactor: Enhance docs, add tests in
 `PrintMatrixInSpiralOrder` (#6636)

* refactor: Enhance docs, add tests in `PrintMatrixInSpiralOrder`

* Fix error in BloomFilter

* Fix

* Fix

* Fix
---
 .../bloomfilter/BloomFilter.java              | 33 +++++---
 .../matrix/PrintAMatrixInSpiralOrder.java     | 36 ++++++--
 .../others/PrintAMatrixInSpiralOrder.java     | 52 ------------
 .../matrix/PrintAMatrixInSpiralOrderTest.java | 83 +++++++++++++++++++
 .../matrix/TestPrintMatrixInSpiralOrder.java  | 26 ------
 .../others/TestPrintMatrixInSpiralOrder.java  | 26 ------
 6 files changed, 135 insertions(+), 121 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java
 create mode 100644 src/test/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrderTest.java
 delete mode 100644 src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java
 delete mode 100644 src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java

diff --git a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
index c84f25bd78e6..90625ad1c902 100644
--- a/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
+++ b/src/main/java/com/thealgorithms/datastructures/bloomfilter/BloomFilter.java
@@ -6,8 +6,10 @@
 /**
  * A generic BloomFilter implementation for probabilistic membership checking.
  * <p>
- * Bloom filters are space-efficient data structures that provide a fast way to test whether an
- * element is a member of a set. They may produce false positives, indicating an element is
+ * Bloom filters are space-efficient data structures that provide a fast way to
+ * test whether an
+ * element is a member of a set. They may produce false positives, indicating an
+ * element is
  * in the set when it is not, but they will never produce false negatives.
  * </p>
  *
@@ -21,11 +23,14 @@ public class BloomFilter<T> {
     private final Hash<T>[] hashFunctions;
 
     /**
-     * Constructs a BloomFilter with a specified number of hash functions and bit array size.
+     * Constructs a BloomFilter with a specified number of hash functions and bit
+     * array size.
      *
      * @param numberOfHashFunctions the number of hash functions to use
-     * @param bitArraySize          the size of the bit array, which determines the capacity of the filter
-     * @throws IllegalArgumentException if numberOfHashFunctions or bitArraySize is less than 1
+     * @param bitArraySize          the size of the bit array, which determines the
+     *                              capacity of the filter
+     * @throws IllegalArgumentException if numberOfHashFunctions or bitArraySize is
+     *                                  less than 1
      */
     @SuppressWarnings("unchecked")
     public BloomFilter(int numberOfHashFunctions, int bitArraySize) {
@@ -39,7 +44,8 @@ public BloomFilter(int numberOfHashFunctions, int bitArraySize) {
     }
 
     /**
-     * Initializes the hash functions with unique indices to ensure different hashing.
+     * Initializes the hash functions with unique indices to ensure different
+     * hashing.
      */
     private void initializeHashFunctions() {
         for (int i = 0; i < numberOfHashFunctions; i++) {
@@ -50,7 +56,8 @@ private void initializeHashFunctions() {
     /**
      * Inserts an element into the Bloom filter.
      * <p>
-     * This method hashes the element using all defined hash functions and sets the corresponding
+     * This method hashes the element using all defined hash functions and sets the
+     * corresponding
      * bits in the bit array.
      * </p>
      *
@@ -66,13 +73,16 @@ public void insert(T key) {
     /**
      * Checks if an element might be in the Bloom filter.
      * <p>
-     * This method checks the bits at the positions computed by each hash function. If any of these
-     * bits are not set, the element is definitely not in the filter. If all bits are set, the element
+     * This method checks the bits at the positions computed by each hash function.
+     * If any of these
+     * bits are not set, the element is definitely not in the filter. If all bits
+     * are set, the element
      * might be in the filter.
      * </p>
      *
      * @param key the element to check for membership in the Bloom filter
-     * @return {@code true} if the element might be in the Bloom filter, {@code false} if it is definitely not
+     * @return {@code true} if the element might be in the Bloom filter,
+     *         {@code false} if it is definitely not
      */
     public boolean contains(T key) {
         for (Hash<T> hash : hashFunctions) {
@@ -87,7 +97,8 @@ public boolean contains(T key) {
     /**
      * Inner class representing a hash function used by the Bloom filter.
      * <p>
-     * Each instance of this class represents a different hash function based on its index.
+     * Each instance of this class represents a different hash function based on its
+     * index.
      * </p>
      *
      * @param <T> The type of elements to be hashed.
diff --git a/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java b/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java
index 2757da1f9023..4ae5970a9574 100644
--- a/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java
+++ b/src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java
@@ -3,17 +3,41 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Utility class to print a matrix in spiral order.
+ * <p>
+ * Given a 2D array (matrix), this class provides a method to return the
+ * elements
+ * of the matrix in spiral order, starting from the top-left corner and moving
+ * clockwise.
+ * </p>
+ *
+ * @author Sadiul Hakim (https://github.com/sadiul-hakim)
+ */
 public class PrintAMatrixInSpiralOrder {
+
     /**
-     * Search a key in row and column wise sorted matrix
+     * Returns the elements of the given matrix in spiral order.
+     *
+     * @param matrix the 2D array to traverse in spiral order
+     * @param row    the number of rows in the matrix
+     * @param col    the number of columns in the matrix
+     * @return a list containing the elements of the matrix in spiral order
      *
-     * @param matrix matrix to be searched
-     * @param row    number of rows matrix has
-     * @param col    number of columns matrix has
-     * @author Sadiul Hakim : https://github.com/sadiul-hakim
+     *         <p>
+     *         Example:
+     *
+     *         <pre>
+     * int[][] matrix = {
+     *   {1, 2, 3},
+     *   {4, 5, 6},
+     *   {7, 8, 9}
+     * };
+     * print(matrix, 3, 3) returns [1, 2, 3, 6, 9, 8, 7, 4, 5]
+     *         </pre>
+     *         </p>
      */
     public List<Integer> print(int[][] matrix, int row, int col) {
-
         // r traverses matrix row wise from first
         int r = 0;
         // c traverses matrix column wise from first
diff --git a/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java b/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java
deleted file mode 100644
index abfdd006879e..000000000000
--- a/src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java
+++ /dev/null
@@ -1,52 +0,0 @@
-package com.thealgorithms.others;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class PrintAMatrixInSpiralOrder {
-    /**
-     * Search a key in row and column wise sorted matrix
-     *
-     * @param matrix matrix to be searched
-     * @param row    number of rows matrix has
-     * @param col    number of columns matrix has
-     * @author Sadiul Hakim : https://github.com/sadiul-hakim
-     */
-    public List<Integer> print(int[][] matrix, int row, int col) {
-        // r traverses matrix row wise from first
-        int r = 0;
-        // c traverses matrix column wise from first
-        int c = 0;
-        int i;
-        List<Integer> result = new ArrayList<>();
-        while (r < row && c < col) {
-            // print first row of matrix
-            for (i = c; i < col; i++) {
-                result.add(matrix[r][i]);
-            }
-            // increase r by one because first row printed
-            r++;
-            // print last column
-            for (i = r; i < row; i++) {
-                result.add(matrix[i][col - 1]);
-            }
-            // decrease col by one because last column has been printed
-            col--;
-            // print rows from last except printed elements
-            if (r < row) {
-                for (i = col - 1; i >= c; i--) {
-                    result.add(matrix[row - 1][i]);
-                }
-                row--;
-            }
-            // print columns from first except printed elements
-            if (c < col) {
-                for (i = row - 1; i >= r; i--) {
-                    result.add(matrix[i][c]);
-                }
-                c++;
-            }
-        }
-        return result;
-    }
-}
diff --git a/src/test/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrderTest.java b/src/test/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrderTest.java
new file mode 100644
index 000000000000..745fdf98f193
--- /dev/null
+++ b/src/test/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrderTest.java
@@ -0,0 +1,83 @@
+package com.thealgorithms.matrix;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class PrintAMatrixInSpiralOrderTest {
+
+    private final PrintAMatrixInSpiralOrder spiralPrinter = new PrintAMatrixInSpiralOrder();
+
+    @Test
+    void testSquareMatrix() {
+        int[][] matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+        List<Integer> expected = Arrays.asList(1, 2, 3, 6, 9, 8, 7, 4, 5);
+        assertEquals(expected, spiralPrinter.print(matrix, 3, 3));
+    }
+
+    @Test
+    void testRectangularMatrixMoreRows() {
+        int[][] matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}, {10, 11, 12}};
+        List<Integer> expected = Arrays.asList(1, 2, 3, 6, 9, 12, 11, 10, 7, 4, 5, 8);
+        assertEquals(expected, spiralPrinter.print(matrix, 4, 3));
+    }
+
+    @Test
+    void testRectangularMatrixMoreCols() {
+        int[][] matrix = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
+        List<Integer> expected = Arrays.asList(1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7);
+        assertEquals(expected, spiralPrinter.print(matrix, 3, 4));
+    }
+
+    @Test
+    void testSingleRow() {
+        int[][] matrix = {{1, 2, 3, 4}};
+        List<Integer> expected = Arrays.asList(1, 2, 3, 4);
+        assertEquals(expected, spiralPrinter.print(matrix, 1, 4));
+    }
+
+    @Test
+    void testSingleColumn() {
+        int[][] matrix = {{1}, {2}, {3}};
+        List<Integer> expected = Arrays.asList(1, 2, 3);
+        assertEquals(expected, spiralPrinter.print(matrix, 3, 1));
+    }
+
+    @Test
+    void testEmptyMatrix() {
+        int[][] matrix = new int[0][0];
+        List<Integer> expected = Collections.emptyList();
+        assertEquals(expected, spiralPrinter.print(matrix, 0, 0));
+    }
+
+    @Test
+    void testOneElementMatrix() {
+        int[][] matrix = {{42}};
+        List<Integer> expected = Collections.singletonList(42);
+        assertEquals(expected, spiralPrinter.print(matrix, 1, 1));
+    }
+
+    @Test
+    void testMatrixWithNegativeNumbers() {
+        int[][] matrix = {{-1, -2}, {-3, -4}};
+        List<Integer> expected = Arrays.asList(-1, -2, -4, -3);
+        assertEquals(expected, spiralPrinter.print(matrix, 2, 2));
+    }
+
+    @Test
+    void testLargeSquareMatrix() {
+        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
+        List<Integer> expected = Arrays.asList(3, 4, 5, 6, 7, 12, 18, 27, 34, 33, 32, 31, 30, 23, 14, 8, 9, 10, 11, 17, 26, 25, 24, 15, 16);
+        assertEquals(expected, spiralPrinter.print(matrix, 5, 5));
+    }
+
+    @Test
+    void testSingleRowWithTwoElements() {
+        int[][] matrix = {{2, 2}};
+        List<Integer> expected = Arrays.asList(2, 2);
+        assertEquals(expected, spiralPrinter.print(matrix, 1, 2));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java b/src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java
deleted file mode 100644
index bb415a5861a8..000000000000
--- a/src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java
+++ /dev/null
@@ -1,26 +0,0 @@
-package com.thealgorithms.matrix;
-
-import static org.junit.jupiter.api.Assertions.assertIterableEquals;
-
-import java.util.List;
-import org.junit.jupiter.api.Test;
-
-public class TestPrintMatrixInSpiralOrder {
-    @Test
-    public void testOne() {
-        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
-        var printClass = new PrintAMatrixInSpiralOrder();
-        List<Integer> res = printClass.print(matrix, matrix.length, matrix[0].length);
-        List<Integer> list = List.of(3, 4, 5, 6, 7, 12, 18, 27, 34, 33, 32, 31, 30, 23, 14, 8, 9, 10, 11, 17, 26, 25, 24, 15, 16);
-        assertIterableEquals(res, list);
-    }
-
-    @Test
-    public void testTwo() {
-        int[][] matrix = {{2, 2}};
-        var printClass = new PrintAMatrixInSpiralOrder();
-        List<Integer> res = printClass.print(matrix, matrix.length, matrix[0].length);
-        List<Integer> list = List.of(2, 2);
-        assertIterableEquals(res, list);
-    }
-}
diff --git a/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java b/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java
deleted file mode 100644
index d35d4bb60c73..000000000000
--- a/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java
+++ /dev/null
@@ -1,26 +0,0 @@
-package com.thealgorithms.others;
-
-import static org.junit.jupiter.api.Assertions.assertIterableEquals;
-
-import java.util.List;
-import org.junit.jupiter.api.Test;
-
-public class TestPrintMatrixInSpiralOrder {
-    @Test
-    public void testOne() {
-        int[][] matrix = {{3, 4, 5, 6, 7}, {8, 9, 10, 11, 12}, {14, 15, 16, 17, 18}, {23, 24, 25, 26, 27}, {30, 31, 32, 33, 34}};
-        var printClass = new PrintAMatrixInSpiralOrder();
-        List<Integer> res = printClass.print(matrix, matrix.length, matrix[0].length);
-        List<Integer> list = List.of(3, 4, 5, 6, 7, 12, 18, 27, 34, 33, 32, 31, 30, 23, 14, 8, 9, 10, 11, 17, 26, 25, 24, 15, 16);
-        assertIterableEquals(res, list);
-    }
-
-    @Test
-    public void testTwo() {
-        int[][] matrix = {{2, 2}};
-        var printClass = new PrintAMatrixInSpiralOrder();
-        List<Integer> res = printClass.print(matrix, matrix.length, matrix[0].length);
-        List<Integer> list = List.of(2, 2);
-        assertIterableEquals(res, list);
-    }
-}

From 48ba1ae4667c4f69b2b4cd34d9f66418db27444d Mon Sep 17 00:00:00 2001
From: Indole Yi <microindole@gmail.com>
Date: Fri, 24 Oct 2025 00:16:46 +0800
Subject: [PATCH 1043/1338] feat(compression): Add LZ77 and LZ78 algorithms
 (#6910)

* feat(compression): Add LZ77 and LZ78 algorithms

* Resolve Spotbugs warning in LZ78 by using Trie structure

* fix code style
---
 .../com/thealgorithms/compression/LZ77.java   | 168 ++++++++++
 .../com/thealgorithms/compression/LZ78.java   | 136 ++++++++
 .../thealgorithms/compression/LZ77Test.java   | 223 +++++++++++++
 .../thealgorithms/compression/LZ78Test.java   | 295 ++++++++++++++++++
 4 files changed, 822 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/compression/LZ77.java
 create mode 100644 src/main/java/com/thealgorithms/compression/LZ78.java
 create mode 100644 src/test/java/com/thealgorithms/compression/LZ77Test.java
 create mode 100644 src/test/java/com/thealgorithms/compression/LZ78Test.java

diff --git a/src/main/java/com/thealgorithms/compression/LZ77.java b/src/main/java/com/thealgorithms/compression/LZ77.java
new file mode 100644
index 000000000000..d02307aa57b5
--- /dev/null
+++ b/src/main/java/com/thealgorithms/compression/LZ77.java
@@ -0,0 +1,168 @@
+package com.thealgorithms.compression;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * An implementation of the Lempel-Ziv 77 (LZ77) compression algorithm.
+ * <p>
+ * LZ77 is a lossless data compression algorithm that works by finding repeated
+ * occurrences of data in a sliding window. It replaces subsequent occurrences
+ * with references (offset, length) to the first occurrence within the window.
+ * </p>
+ * <p>
+ * This implementation uses a simple sliding window and lookahead buffer approach.
+ * Output format is a sequence of tuples (offset, length, next_character).
+ * </p>
+ * <p>
+ * Time Complexity: O(n*W) in this naive implementation, where n is the input length
+ * and W is the window size, due to the search for the longest match. More advanced
+ * data structures (like suffix trees) can improve this.
+ * </p>
+ * <p>
+ * References:
+ * <ul>
+ * <li><a href="https://en.wikipedia.org/wiki/LZ77_and_LZ78#LZ77">Wikipedia: LZ77</a></li>
+ * </ul>
+ * </p>
+ */
+public final class LZ77 {
+
+    private static final int DEFAULT_WINDOW_SIZE = 4096;
+    private static final int DEFAULT_LOOKAHEAD_BUFFER_SIZE = 16;
+    private static final char END_OF_STREAM = '\u0000';
+    private LZ77() {
+    }
+
+    /**
+     * Represents a token in the LZ77 compressed output.
+     * Stores the offset back into the window, the length of the match,
+     * and the next character after the match (or END_OF_STREAM if at end).
+     */
+    public record Token(int offset, int length, char nextChar) {
+    }
+
+    /**
+     * Compresses the input text using the LZ77 algorithm.
+     *
+     * @param text The input string to compress. Must not be null.
+     * @param windowSize The size of the sliding window (search buffer). Must be positive.
+     * @param lookaheadBufferSize The size of the lookahead buffer. Must be positive.
+     * @return A list of {@link Token} objects representing the compressed data.
+     * @throws IllegalArgumentException if windowSize or lookaheadBufferSize are not positive.
+     */
+    public static List<Token> compress(String text, int windowSize, int lookaheadBufferSize) {
+        if (text == null) {
+            return new ArrayList<>();
+        }
+        if (windowSize <= 0 || lookaheadBufferSize <= 0) {
+            throw new IllegalArgumentException("Window size and lookahead buffer size must be positive.");
+        }
+
+        List<Token> compressedOutput = new ArrayList<>();
+        int currentPosition = 0;
+
+        while (currentPosition < text.length()) {
+            int bestMatchDistance = 0;
+            int bestMatchLength = 0;
+
+            // Define the start of the search window
+            int searchBufferStart = Math.max(0, currentPosition - windowSize);
+            // Define the end of the lookahead buffer (don't go past text length)
+            int lookaheadEnd = Math.min(currentPosition + lookaheadBufferSize, text.length());
+
+            // Search for the longest match in the window
+            for (int i = searchBufferStart; i < currentPosition; i++) {
+                int currentMatchLength = 0;
+
+                // Check how far the match extends into the lookahead buffer
+                // This allows for overlapping matches (e.g., "aaa" can match with offset 1)
+                while (currentPosition + currentMatchLength < lookaheadEnd) {
+                    int sourceIndex = i + currentMatchLength;
+
+                    // Handle overlapping matches (run-length encoding within LZ77)
+                    // When we've matched beyond our starting position, wrap around using modulo
+                    if (sourceIndex >= currentPosition) {
+                        int offset = currentPosition - i;
+                        sourceIndex = i + (currentMatchLength % offset);
+                    }
+
+                    if (text.charAt(sourceIndex) == text.charAt(currentPosition + currentMatchLength)) {
+                        currentMatchLength++;
+                    } else {
+                        break;
+                    }
+                }
+
+                // If this match is longer than the best found so far
+                if (currentMatchLength > bestMatchLength) {
+                    bestMatchLength = currentMatchLength;
+                    bestMatchDistance = currentPosition - i; // Calculate offset from current position
+                }
+            }
+
+            char nextChar;
+            if (currentPosition + bestMatchLength < text.length()) {
+                nextChar = text.charAt(currentPosition + bestMatchLength);
+            } else {
+                nextChar = END_OF_STREAM;
+            }
+
+            // Add the token to the output
+            compressedOutput.add(new Token(bestMatchDistance, bestMatchLength, nextChar));
+
+            // Move the current position forward
+            // If we're at the end and had a match, just move by the match length
+            if (nextChar == END_OF_STREAM) {
+                currentPosition += bestMatchLength;
+            } else {
+                currentPosition += bestMatchLength + 1;
+            }
+        }
+
+        return compressedOutput;
+    }
+
+    /**
+     * Compresses the input text using the LZ77 algorithm with default buffer sizes.
+     *
+     * @param text The input string to compress. Must not be null.
+     * @return A list of {@link Token} objects representing the compressed data.
+     */
+    public static List<Token> compress(String text) {
+        return compress(text, DEFAULT_WINDOW_SIZE, DEFAULT_LOOKAHEAD_BUFFER_SIZE);
+    }
+
+    /**
+     * Decompresses a list of LZ77 tokens back into the original string.
+     *
+     * @param compressedData The list of {@link Token} objects. Must not be null.
+     * @return The original, uncompressed string.
+     */
+    public static String decompress(List<Token> compressedData) {
+        if (compressedData == null) {
+            return "";
+        }
+
+        StringBuilder decompressedText = new StringBuilder();
+
+        for (Token token : compressedData) {
+            // Copy matched characters from the sliding window
+            if (token.length > 0) {
+                int startIndex = decompressedText.length() - token.offset;
+
+                // Handle overlapping matches (e.g., when length > offset)
+                for (int i = 0; i < token.length; i++) {
+                    decompressedText.append(decompressedText.charAt(startIndex + i));
+                }
+            }
+
+            // Append the next character (if not END_OF_STREAM)
+            if (token.nextChar != END_OF_STREAM) {
+                decompressedText.append(token.nextChar);
+            }
+        }
+
+        return decompressedText.toString();
+    }
+}
diff --git a/src/main/java/com/thealgorithms/compression/LZ78.java b/src/main/java/com/thealgorithms/compression/LZ78.java
new file mode 100644
index 000000000000..904c379cc2a2
--- /dev/null
+++ b/src/main/java/com/thealgorithms/compression/LZ78.java
@@ -0,0 +1,136 @@
+package com.thealgorithms.compression;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * An implementation of the Lempel-Ziv 78 (LZ78) compression algorithm.
+ * <p>
+ * LZ78 is a dictionary-based lossless data compression algorithm. It processes
+ * input data sequentially, building a dictionary of phrases encountered so far.
+ * It outputs pairs (dictionary_index, next_character), representing
+ * the longest match found in the dictionary plus the character that follows it.
+ * </p>
+ * <p>
+ * This implementation builds the dictionary dynamically during compression.
+ * The dictionary index 0 represents the empty string (no prefix).
+ * </p>
+ * <p>
+ * Time Complexity: O(n) on average for compression and decompression, assuming
+ * efficient dictionary lookups (using a HashMap), where n is the
+ * length of the input string.
+ * </p>
+ * <p>
+ * References:
+ * <ul>
+ * <li><a href="https://en.wikipedia.org/wiki/LZ77_and_LZ78#LZ78">Wikipedia: LZ78</a></li>
+ * </ul>
+ * </p>
+ */
+public final class LZ78 {
+
+    /**
+     * Special character used to mark end of stream when needed.
+     */
+    private static final char END_OF_STREAM = '\u0000';
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private LZ78() {
+    }
+
+    /**
+     * Represents a token in the LZ78 compressed output.
+     * Stores the index of the matching prefix in the dictionary and the next character.
+     * Index 0 represents the empty string (no prefix).
+     */
+    public record Token(int index, char nextChar) {
+    }
+
+    /**
+     * A node in the dictionary trie structure.
+     * Each node represents a phrase and can have child nodes for extended phrases.
+     */
+    private static final class TrieNode {
+        Map<Character, TrieNode> children = new HashMap<>();
+        int index = -1; // -1 means not assigned yet
+    }
+
+    /**
+     * Compresses the input text using the LZ78 algorithm.
+     *
+     * @param text The input string to compress. Must not be null.
+     * @return A list of {@link Token} objects representing the compressed data.
+     */
+    public static List<Token> compress(String text) {
+        if (text == null || text.isEmpty()) {
+            return new ArrayList<>();
+        }
+
+        List<Token> compressedOutput = new ArrayList<>();
+        TrieNode root = new TrieNode();
+        int nextDictionaryIndex = 1;
+
+        TrieNode currentNode = root;
+        int lastMatchedIndex = 0;
+
+        for (int i = 0; i < text.length(); i++) {
+            char currentChar = text.charAt(i);
+
+            if (currentNode.children.containsKey(currentChar)) {
+                currentNode = currentNode.children.get(currentChar);
+                lastMatchedIndex = currentNode.index;
+            } else {
+                // Output: (index of longest matching prefix, current character)
+                compressedOutput.add(new Token(lastMatchedIndex, currentChar));
+
+                TrieNode newNode = new TrieNode();
+                newNode.index = nextDictionaryIndex++;
+                currentNode.children.put(currentChar, newNode);
+
+                currentNode = root;
+                lastMatchedIndex = 0;
+            }
+        }
+
+        // Handle remaining phrase at end of input
+        if (currentNode != root) {
+            compressedOutput.add(new Token(lastMatchedIndex, END_OF_STREAM));
+        }
+
+        return compressedOutput;
+    }
+
+    /**
+     * Decompresses a list of LZ78 tokens back into the original string.
+     *
+     * @param compressedData The list of {@link Token} objects. Must not be null.
+     * @return The original, uncompressed string.
+     */
+    public static String decompress(List<Token> compressedData) {
+        if (compressedData == null || compressedData.isEmpty()) {
+            return "";
+        }
+
+        StringBuilder decompressedText = new StringBuilder();
+        Map<Integer, String> dictionary = new HashMap<>();
+        int nextDictionaryIndex = 1;
+
+        for (Token token : compressedData) {
+            String prefix = (token.index == 0) ? "" : dictionary.get(token.index);
+
+            if (token.nextChar == END_OF_STREAM) {
+                decompressedText.append(prefix);
+            } else {
+                String currentPhrase = prefix + token.nextChar;
+                decompressedText.append(currentPhrase);
+                dictionary.put(nextDictionaryIndex++, currentPhrase);
+            }
+        }
+
+        return decompressedText.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/compression/LZ77Test.java b/src/test/java/com/thealgorithms/compression/LZ77Test.java
new file mode 100644
index 000000000000..86732d48a54a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/compression/LZ77Test.java
@@ -0,0 +1,223 @@
+package com.thealgorithms.compression;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class LZ77Test {
+
+    @Test
+    @DisplayName("Test compression and decompression of a simple repeating string")
+    void testSimpleRepeatingString() {
+        String original = "ababcbababaa";
+        List<LZ77.Token> compressed = LZ77.compress(original, 10, 4);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test compression and decompression of a string with no repeats initially")
+    void testNoInitialRepeats() {
+        String original = "abcdefgh";
+        List<LZ77.Token> compressed = LZ77.compress(original);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test compression and decompression of a longer example")
+    void testLongerExample() {
+        String original = "TOBEORNOTTOBEORTOBEORNOT";
+        List<LZ77.Token> compressed = LZ77.compress(original, 20, 10);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test empty string compression and decompression")
+    void testEmptyString() {
+        String original = "";
+        List<LZ77.Token> compressed = LZ77.compress(original);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+        assertTrue(compressed.isEmpty());
+    }
+
+    @Test
+    @DisplayName("Test null string compression")
+    void testNullStringCompress() {
+        List<LZ77.Token> compressed = LZ77.compress(null);
+        assertTrue(compressed.isEmpty());
+    }
+
+    @Test
+    @DisplayName("Test null list decompression")
+    void testNullListDecompress() {
+        String decompressed = LZ77.decompress(null);
+        assertEquals("", decompressed);
+    }
+
+    @Test
+    @DisplayName("Test invalid buffer sizes throw exception")
+    void testInvalidBufferSizes() {
+        assertThrows(IllegalArgumentException.class, () -> LZ77.compress("test", 0, 5));
+        assertThrows(IllegalArgumentException.class, () -> LZ77.compress("test", 5, 0));
+        assertThrows(IllegalArgumentException.class, () -> LZ77.compress("test", -1, 5));
+        assertThrows(IllegalArgumentException.class, () -> LZ77.compress("test", 5, -1));
+    }
+
+    @Test
+    @DisplayName("Test string with all same characters")
+    void testAllSameCharacters() {
+        String original = "AAAAAA";
+        List<LZ77.Token> compressed = LZ77.compress(original, 10, 5);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // Should achieve good compression for repeated characters
+        assertTrue(compressed.size() < original.length());
+    }
+
+    @Test
+    @DisplayName("Test string with all unique characters")
+    void testAllUniqueCharacters() {
+        String original = "abcdefghijklmnop";
+        List<LZ77.Token> compressed = LZ77.compress(original, 10, 5);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // No compression expected for unique characters
+        assertEquals(original.length(), compressed.size());
+    }
+
+    @Test
+    @DisplayName("Test single character string")
+    void testSingleCharacter() {
+        String original = "a";
+        List<LZ77.Token> compressed = LZ77.compress(original);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+        assertEquals(1, compressed.size());
+    }
+
+    @Test
+    @DisplayName("Test match that goes exactly to the end")
+    void testMatchToEnd() {
+        String original = "abcabc";
+        List<LZ77.Token> compressed = LZ77.compress(original, 10, 10);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test with very small window size")
+    void testSmallWindowSize() {
+        String original = "ababababab";
+        List<LZ77.Token> compressed = LZ77.compress(original, 2, 4);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test with very small lookahead buffer")
+    void testSmallLookaheadBuffer() {
+        String original = "ababcbababaa";
+        List<LZ77.Token> compressed = LZ77.compress(original, 10, 2);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test repeating pattern at the end")
+    void testRepeatingPatternAtEnd() {
+        String original = "xyzabcabcabcabc";
+        List<LZ77.Token> compressed = LZ77.compress(original, 15, 8);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test overlapping matches (run-length encoding case)")
+    void testOverlappingMatches() {
+        String original = "aaaaaa";
+        List<LZ77.Token> compressed = LZ77.compress(original, 10, 10);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test complex pattern with multiple repeats")
+    void testComplexPattern() {
+        String original = "abcabcabcxyzxyzxyz";
+        List<LZ77.Token> compressed = LZ77.compress(original, 20, 10);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test with special characters")
+    void testSpecialCharacters() {
+        String original = "hello world! @#$%^&*()";
+        List<LZ77.Token> compressed = LZ77.compress(original);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test with numbers")
+    void testWithNumbers() {
+        String original = "1234567890123456";
+        List<LZ77.Token> compressed = LZ77.compress(original, 15, 8);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test long repeating sequence")
+    void testLongRepeatingSequence() {
+        String original = "abcdefgh".repeat(10);
+        List<LZ77.Token> compressed = LZ77.compress(original, 50, 20);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // Should achieve significant compression
+        assertTrue(compressed.size() < original.length() / 2);
+    }
+
+    @Test
+    @DisplayName("Test compression effectiveness")
+    void testCompressionEffectiveness() {
+        String original = "ababababababab";
+        List<LZ77.Token> compressed = LZ77.compress(original, 20, 10);
+
+        // Verify that compression actually reduces the data size
+        // Each token represents potentially multiple characters
+        assertTrue(compressed.size() <= original.length());
+
+        // Verify decompression
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test with mixed case letters")
+    void testMixedCase() {
+        String original = "AaBbCcAaBbCc";
+        List<LZ77.Token> compressed = LZ77.compress(original);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test default parameters")
+    void testDefaultParameters() {
+        String original = "This is a test string with some repeated patterns. This is repeated.";
+        List<LZ77.Token> compressed = LZ77.compress(original);
+        String decompressed = LZ77.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/compression/LZ78Test.java b/src/test/java/com/thealgorithms/compression/LZ78Test.java
new file mode 100644
index 000000000000..7889b50b76f3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/compression/LZ78Test.java
@@ -0,0 +1,295 @@
+package com.thealgorithms.compression;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class LZ78Test {
+
+    @Test
+    @DisplayName("Test compression and decompression of a simple repeating string")
+    void testSimpleRepeatingString() {
+        String original = "ababcbababaa";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test compression and decompression example ABAABABAABAB")
+    void testStandardExample() {
+        String original = "ABAABABAABAB";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // Verify the compression produces expected tokens
+        // Expected: (0,A)(0,B)(1,A)(2,B)(3,A)(4,B)
+        // Where dictionary builds as: 1:A, 2:B, 3:AA, 4:BA, 5:ABA, 6:BAB
+        assertEquals(6, compressed.size());
+        assertEquals(0, compressed.get(0).index());
+        assertEquals('A', compressed.get(0).nextChar());
+        assertEquals(0, compressed.get(1).index());
+        assertEquals('B', compressed.get(1).nextChar());
+        assertEquals(1, compressed.get(2).index());
+        assertEquals('A', compressed.get(2).nextChar());
+    }
+
+    @Test
+    @DisplayName("Test compression and decompression of a longer example")
+    void testLongerExample() {
+        String original = "TOBEORNOTTOBEORTOBEORNOT";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test empty string compression and decompression")
+    void testEmptyString() {
+        String original = "";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+        assertTrue(compressed.isEmpty());
+    }
+
+    @Test
+    @DisplayName("Test null string compression")
+    void testNullStringCompress() {
+        List<LZ78.Token> compressed = LZ78.compress(null);
+        assertTrue(compressed.isEmpty());
+    }
+
+    @Test
+    @DisplayName("Test null list decompression")
+    void testNullListDecompress() {
+        String decompressed = LZ78.decompress(null);
+        assertEquals("", decompressed);
+    }
+
+    @Test
+    @DisplayName("Test string with all same characters")
+    void testAllSameCharacters() {
+        String original = "AAAAAA";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // Should achieve good compression: (0,A)(1,A)(2,A)...
+        assertTrue(compressed.size() <= 4); // Builds: A, AA, AAA, etc.
+    }
+
+    @Test
+    @DisplayName("Test string with all unique characters")
+    void testAllUniqueCharacters() {
+        String original = "abcdefg";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // No compression for unique characters
+        assertEquals(original.length(), compressed.size());
+
+        // Each token should have index 0 (empty prefix)
+        for (LZ78.Token token : compressed) {
+            assertEquals(0, token.index());
+        }
+    }
+
+    @Test
+    @DisplayName("Test single character string")
+    void testSingleCharacter() {
+        String original = "a";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+        assertEquals(1, compressed.size());
+        assertEquals(0, compressed.getFirst().index());
+        assertEquals('a', compressed.getFirst().nextChar());
+    }
+
+    @Test
+    @DisplayName("Test two character string")
+    void testTwoCharacters() {
+        String original = "ab";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+        assertEquals(2, compressed.size());
+    }
+
+    @Test
+    @DisplayName("Test repeating pairs")
+    void testRepeatingPairs() {
+        String original = "ababab";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // Should compress well: (0,a)(0,b)(1,b) or similar
+        assertTrue(compressed.size() < original.length());
+    }
+
+    @Test
+    @DisplayName("Test growing patterns")
+    void testGrowingPatterns() {
+        String original = "abcabcdabcde";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test dictionary building correctness")
+    void testDictionaryBuilding() {
+        String original = "aabaabaab";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // Verify first few tokens
+        // Expected pattern: (0,a)(1,b)(2,a)(3,b) building dictionary 1:a, 2:ab, 3:aa, 4:aab
+        assertTrue(compressed.size() > 0);
+        assertEquals(0, compressed.getFirst().index()); // First char always has index 0
+    }
+
+    @Test
+    @DisplayName("Test with special characters")
+    void testSpecialCharacters() {
+        String original = "hello world! hello!";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test with numbers")
+    void testWithNumbers() {
+        String original = "1234512345";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // Should achieve compression
+        assertTrue(compressed.size() < original.length());
+    }
+
+    @Test
+    @DisplayName("Test long repeating sequence")
+    void testLongRepeatingSequence() {
+        String original = "abcdefgh".repeat(5);
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // LZ78 should achieve some compression for repeating sequences
+        assertTrue(compressed.size() < original.length(), "Compressed size should be less than original length");
+    }
+
+    @Test
+    @DisplayName("Test alternating characters")
+    void testAlternatingCharacters() {
+        String original = "ababababab";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test compression effectiveness")
+    void testCompressionEffectiveness() {
+        String original = "the quick brown fox jumps over the lazy dog the quick brown fox";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // Should achieve some compression due to repeated phrases
+        assertTrue(compressed.size() < original.length());
+    }
+
+    @Test
+    @DisplayName("Test with mixed case letters")
+    void testMixedCase() {
+        String original = "AaBbCcAaBbCc";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test palindrome string")
+    void testPalindrome() {
+        String original = "abccba";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test highly compressible pattern")
+    void testHighlyCompressible() {
+        String original = "aaaaaaaaaa";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+
+        // Should achieve excellent compression ratio
+        assertTrue(compressed.size() <= 4);
+    }
+
+    @Test
+    @DisplayName("Test empty list decompression")
+    void testEmptyListDecompress() {
+        List<LZ78.Token> compressed = List.of();
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals("", decompressed);
+    }
+
+    @Test
+    @DisplayName("Test binary-like pattern")
+    void testBinaryPattern() {
+        String original = "0101010101";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test nested patterns")
+    void testNestedPatterns() {
+        String original = "abcabcdefabcdefghi";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test whitespace handling")
+    void testWhitespace() {
+        String original = "a b c a b c";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+
+    @Test
+    @DisplayName("Test token structure correctness")
+    void testTokenStructure() {
+        String original = "abc";
+        List<LZ78.Token> compressed = LZ78.compress(original);
+
+        // All tokens should have valid indices (>= 0)
+        for (LZ78.Token token : compressed) {
+            assertTrue(token.index() >= 0);
+            assertNotNull(token.nextChar());
+        }
+
+        String decompressed = LZ78.decompress(compressed);
+        assertEquals(original, decompressed);
+    }
+}

From ab65ac6485056cb79512acfa6df13a2ed510824f Mon Sep 17 00:00:00 2001
From: Indolyn Yi <microindole@gmail.com>
Date: Sat, 25 Oct 2025 17:29:45 +0800
Subject: [PATCH 1044/1338] feat(compression): Add Burrows-Wheeler Transform
 (BWT) and Move-to-Front (MTF) (#6926)

* feat(compression): Add Burrows-Wheeler Transform (BWT) and Move-to-Front (MTF)

* Resolve SpotBugs

* fix code style
---
 .../compression/BurrowsWheelerTransform.java  | 220 ++++++++++++++++++
 .../compression/MoveToFront.java              | 164 +++++++++++++
 .../BurrowsWheelerTransformTest.java          | 124 ++++++++++
 .../compression/MoveToFrontTest.java          |  92 ++++++++
 4 files changed, 600 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/compression/BurrowsWheelerTransform.java
 create mode 100644 src/main/java/com/thealgorithms/compression/MoveToFront.java
 create mode 100644 src/test/java/com/thealgorithms/compression/BurrowsWheelerTransformTest.java
 create mode 100644 src/test/java/com/thealgorithms/compression/MoveToFrontTest.java

diff --git a/src/main/java/com/thealgorithms/compression/BurrowsWheelerTransform.java b/src/main/java/com/thealgorithms/compression/BurrowsWheelerTransform.java
new file mode 100644
index 000000000000..a148517e5b55
--- /dev/null
+++ b/src/main/java/com/thealgorithms/compression/BurrowsWheelerTransform.java
@@ -0,0 +1,220 @@
+package com.thealgorithms.compression;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Implementation of the Burrows-Wheeler Transform (BWT) and its inverse.
+ * <p>
+ * BWT is a reversible data transformation algorithm that rearranges a string into runs of
+ * similar characters. While not a compression algorithm itself, it significantly improves
+ * the compressibility of data for subsequent algorithms like Move-to-Front encoding and
+ * Run-Length Encoding.
+ * </p>
+ *
+ * <p>The transform works by:
+ * <ol>
+ *   <li>Generating all rotations of the input string</li>
+ *   <li>Sorting these rotations lexicographically</li>
+ *   <li>Taking the last column of the sorted matrix as output</li>
+ *   <li>Recording the index of the original string in the sorted matrix</li>
+ * </ol>
+ * </p>
+ *
+ * <p><b>Important:</b> The input string should end with a unique end-of-string marker
+ * (typically '$') that:
+ * <ul>
+ *   <li>Does not appear anywhere else in the text</li>
+ *   <li>Is lexicographically smaller than all other characters</li>
+ *   <li>Ensures unique rotations and enables correct inverse transformation</li>
+ * </ul>
+ * Without this marker, the inverse transform may not correctly reconstruct the original string.
+ * </p>
+ *
+ * <p><b>Time Complexity:</b>
+ * <ul>
+ *   <li>Forward transform: O(n² log n) where n is the string length</li>
+ *   <li>Inverse transform: O(n) using the LF-mapping technique</li>
+ * </ul>
+ * </p>
+ *
+ * <p><b>Example:</b></p>
+ * <pre>
+ * Input:  "banana$"
+ * Output: BWTResult("annb$aa", 4)
+ *         - "annb$aa" is the transformed string (groups similar characters)
+ *         - 4 is the index of the original string in the sorted rotations
+ * </pre>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Burrows%E2%80%93Wheeler_transform">Burrows–Wheeler transform (Wikipedia)</a>
+ */
+public final class BurrowsWheelerTransform {
+
+    private BurrowsWheelerTransform() {
+    }
+
+    /**
+     * A container for the result of the forward BWT.
+     * <p>
+     * Contains the transformed string and the index of the original string
+     * in the sorted rotations matrix, both of which are required for the
+     * inverse transformation.
+     * </p>
+     */
+    public static class BWTResult {
+        /** The transformed string (last column of the sorted rotation matrix) */
+        public final String transformed;
+
+        /** The index of the original string in the sorted rotations matrix */
+        public final int originalIndex;
+
+        /**
+         * Constructs a BWTResult with the transformed string and original index.
+         *
+         * @param transformed the transformed string (L-column)
+         * @param originalIndex the index of the original string in sorted rotations
+         */
+        public BWTResult(String transformed, int originalIndex) {
+            this.transformed = transformed;
+            this.originalIndex = originalIndex;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) {
+                return true;
+            }
+            if (obj == null || getClass() != obj.getClass()) {
+                return false;
+            }
+            BWTResult bwtResult = (BWTResult) obj;
+            return originalIndex == bwtResult.originalIndex && transformed.equals(bwtResult.transformed);
+        }
+
+        @Override
+        public int hashCode() {
+            return 31 * transformed.hashCode() + originalIndex;
+        }
+
+        @Override
+        public String toString() {
+            return "BWTResult[transformed=" + transformed + ", originalIndex=" + originalIndex + "]";
+        }
+    }
+
+    /**
+     * Performs the forward Burrows-Wheeler Transform on the input string.
+     * <p>
+     * The algorithm generates all cyclic rotations of the input, sorts them
+     * lexicographically, and returns the last column of this sorted matrix
+     * along with the position of the original string.
+     * </p>
+     *
+     * <p><b>Note:</b> It is strongly recommended that the input string ends with
+     * a unique end-of-string marker (e.g., '$') that is lexicographically smaller
+     * than any other character in the string. This ensures correct inversion.</p>
+     *
+     * @param text the input string to transform; must not be {@code null}
+     * @return a {@link BWTResult} object containing the transformed string (L-column)
+     *         and the index of the original string in the sorted rotations matrix;
+     *         returns {@code BWTResult("", -1)} for empty input
+     * @throws NullPointerException if {@code text} is {@code null}
+     */
+    public static BWTResult transform(String text) {
+        if (text == null || text.isEmpty()) {
+            return new BWTResult("", -1);
+        }
+
+        int n = text.length();
+
+        // Generate all rotations of the input string
+        String[] rotations = new String[n];
+        for (int i = 0; i < n; i++) {
+            rotations[i] = text.substring(i) + text.substring(0, i);
+        }
+
+        // Sort rotations lexicographically
+        Arrays.sort(rotations);
+        int originalIndex = Arrays.binarySearch(rotations, text);
+        StringBuilder lastColumn = new StringBuilder(n);
+        for (int i = 0; i < n; i++) {
+            lastColumn.append(rotations[i].charAt(n - 1));
+        }
+
+        return new BWTResult(lastColumn.toString(), originalIndex);
+    }
+
+    /**
+     * Performs the inverse Burrows-Wheeler Transform using the LF-mapping technique.
+     * <p>
+     * The LF-mapping (Last-First mapping) is an efficient method to reconstruct
+     * the original string from the BWT output without explicitly reconstructing
+     * the entire sorted rotations matrix.
+     * </p>
+     *
+     * <p>The algorithm works by:
+     * <ol>
+     *   <li>Creating the first column by sorting the BWT string</li>
+     *   <li>Building a mapping from first column indices to last column indices</li>
+     *   <li>Following this mapping starting from the original index to reconstruct the string</li>
+     * </ol>
+     * </p>
+     *
+     * @param bwtString the transformed string (L-column) from the forward transform; must not be {@code null}
+     * @param originalIndex the index of the original string row from the forward transform;
+     *                      use -1 for empty strings
+     * @return the original, untransformed string; returns empty string if input is empty or {@code originalIndex} is -1
+     * @throws NullPointerException if {@code bwtString} is {@code null}
+     * @throws IllegalArgumentException if {@code originalIndex} is out of valid range (except -1)
+     */
+    public static String inverseTransform(String bwtString, int originalIndex) {
+        if (bwtString == null || bwtString.isEmpty() || originalIndex == -1) {
+            return "";
+        }
+
+        int n = bwtString.length();
+        if (originalIndex < 0 || originalIndex >= n) {
+            throw new IllegalArgumentException("Original index must be between 0 and " + (n - 1) + ", got: " + originalIndex);
+        }
+
+        char[] lastColumn = bwtString.toCharArray();
+        char[] firstColumn = bwtString.toCharArray();
+        Arrays.sort(firstColumn);
+
+        // Create the "next" array for LF-mapping.
+        // next[i] stores the row index in the last column that corresponds to firstColumn[i]
+        int[] next = new int[n];
+
+        // Track the count of each character seen so far in the last column
+        Map<Character, Integer> countMap = new HashMap<>();
+
+        // Store the first occurrence index of each character in the first column
+        Map<Character, Integer> firstOccurrence = new HashMap<>();
+
+        for (int i = 0; i < n; i++) {
+            if (!firstOccurrence.containsKey(firstColumn[i])) {
+                firstOccurrence.put(firstColumn[i], i);
+            }
+        }
+
+        // Build the LF-mapping
+        for (int i = 0; i < n; i++) {
+            char c = lastColumn[i];
+            int count = countMap.getOrDefault(c, 0);
+            int firstIndex = firstOccurrence.get(c);
+            next[firstIndex + count] = i;
+            countMap.put(c, count + 1);
+        }
+
+        // Reconstruct the original string by following the LF-mapping
+        StringBuilder originalString = new StringBuilder(n);
+        int currentRow = originalIndex;
+        for (int i = 0; i < n; i++) {
+            originalString.append(firstColumn[currentRow]);
+            currentRow = next[currentRow];
+        }
+
+        return originalString.toString();
+    }
+}
diff --git a/src/main/java/com/thealgorithms/compression/MoveToFront.java b/src/main/java/com/thealgorithms/compression/MoveToFront.java
new file mode 100644
index 000000000000..fa8976df8262
--- /dev/null
+++ b/src/main/java/com/thealgorithms/compression/MoveToFront.java
@@ -0,0 +1,164 @@
+package com.thealgorithms.compression;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * Implementation of the Move-to-Front (MTF) transform and its inverse.
+ * <p>
+ * MTF is a data transformation algorithm that encodes each symbol in the input
+ * as its current position in a dynamically-maintained list, then moves that symbol
+ * to the front of the list. This transformation is particularly effective when used
+ * after the Burrows-Wheeler Transform (BWT), as BWT groups similar characters together.
+ * </p>
+ *
+ * <p>The transform converts runs of repeated characters into sequences of small integers
+ * (often zeros), which are highly compressible by subsequent entropy encoding algorithms
+ * like Run-Length Encoding (RLE) or Huffman coding. This technique is used in the
+ * bzip2 compression algorithm.
+ * </p>
+ *
+ * <p><b>How it works:</b>
+ * <ol>
+ *   <li>Maintain a list of symbols (the alphabet), initially in a fixed order</li>
+ *   <li>For each input symbol:
+ *     <ul>
+ *       <li>Output its current index in the list</li>
+ *       <li>Move that symbol to the front of the list</li>
+ *     </ul>
+ *   </li>
+ * </ol>
+ * This means frequently occurring symbols quickly move to the front and are encoded
+ * with small indices (often 0), while rare symbols remain near the back.
+ * </p>
+ *
+ * <p><b>Time Complexity:</b>
+ * <ul>
+ *   <li>Forward transform: O(n × m) where n is input length and m is alphabet size</li>
+ *   <li>Inverse transform: O(n × m)</li>
+ * </ul>
+ * Note: Using {@link LinkedList} for O(1) insertions and O(m) search operations.
+ * </p>
+ *
+ * <p><b>Example:</b></p>
+ * <pre>
+ * Input:    "annb$aa"
+ * Alphabet: "$abn" (initial order)
+ * Output:   [1, 3, 0, 3, 3, 3, 0]
+ *
+ * Step-by-step:
+ * - 'a': index 1 in [$,a,b,n] → output 1, list becomes [a,$,b,n]
+ * - 'n': index 3 in [a,$,b,n] → output 3, list becomes [n,a,$,b]
+ * - 'n': index 0 in [n,a,$,b] → output 0, list stays [n,a,$,b]
+ * - 'b': index 3 in [n,a,$,b] → output 3, list becomes [b,n,a,$]
+ * - etc.
+ *
+ * Notice how repeated 'n' characters produce zeros after the first occurrence!
+ * </pre>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Move-to-front_transform">Move-to-front transform (Wikipedia)</a>
+ */
+public final class MoveToFront {
+
+    private MoveToFront() {
+    }
+
+    /**
+     * Performs the forward Move-to-Front transform.
+     * <p>
+     * Converts the input string into a list of integers, where each integer represents
+     * the position of the corresponding character in a dynamically-maintained alphabet list.
+     * </p>
+     *
+     * <p><b>Note:</b> All characters in the input text must exist in the provided alphabet,
+     * otherwise an {@link IllegalArgumentException} is thrown. The alphabet should contain
+     * all unique characters that may appear in the input.</p>
+     *
+     * @param text the input string to transform; if empty, returns an empty list
+     * @param initialAlphabet a string containing the initial ordered set of symbols
+     *                        (e.g., "$abn" or the full ASCII set); must not be empty
+     *                        when {@code text} is non-empty
+     * @return a list of integers representing the transformed data, where each integer
+     *         is the index of the corresponding input character in the current alphabet state
+     * @throws IllegalArgumentException if {@code text} is non-empty and {@code initialAlphabet}
+     *                                  is {@code null} or empty
+     * @throws IllegalArgumentException if any character in {@code text} is not found in
+     *                                  {@code initialAlphabet}
+     */
+    public static List<Integer> transform(String text, String initialAlphabet) {
+        if (text == null || text.isEmpty()) {
+            return new ArrayList<>();
+        }
+        if (initialAlphabet == null || initialAlphabet.isEmpty()) {
+            throw new IllegalArgumentException("Alphabet cannot be null or empty when text is not empty.");
+        }
+
+        List<Integer> output = new ArrayList<>(text.length());
+
+        // Use LinkedList for O(1) add-to-front and O(n) remove operations
+        // This is more efficient than ArrayList for the move-to-front pattern
+        List<Character> alphabet = initialAlphabet.chars().mapToObj(c -> (char) c).collect(Collectors.toCollection(LinkedList::new));
+
+        for (char c : text.toCharArray()) {
+            int index = alphabet.indexOf(c);
+            if (index == -1) {
+                throw new IllegalArgumentException("Symbol '" + c + "' not found in the initial alphabet.");
+            }
+
+            output.add(index);
+
+            // Move the character to the front
+            Character symbol = alphabet.remove(index);
+            alphabet.addFirst(symbol);
+        }
+        return output;
+    }
+
+    /**
+     * Performs the inverse Move-to-Front transform.
+     * <p>
+     * Reconstructs the original string from the list of indices produced by the
+     * forward transform. This requires the exact same initial alphabet that was
+     * used in the forward transform.
+     * </p>
+     *
+     * <p><b>Important:</b> The {@code initialAlphabet} parameter must be identical
+     * to the one used in the forward transform, including character order, or the
+     * output will be incorrect.</p>
+     *
+     * @param indices The list of integers from the forward transform.
+     * @param initialAlphabet the exact same initial alphabet string used for the forward transform;
+     *                        if {@code null} or empty, returns an empty string
+     * @return the original, untransformed string
+     * @throws IllegalArgumentException if any index in {@code indices} is negative or
+     *                                  exceeds the current alphabet size
+     */
+    public static String inverseTransform(Collection<Integer> indices, String initialAlphabet) {
+        if (indices == null || indices.isEmpty() || initialAlphabet == null || initialAlphabet.isEmpty()) {
+            return "";
+        }
+
+        StringBuilder output = new StringBuilder(indices.size());
+
+        // Use LinkedList for O(1) add-to-front and O(n) remove operations
+        List<Character> alphabet = initialAlphabet.chars().mapToObj(c -> (char) c).collect(Collectors.toCollection(LinkedList::new));
+
+        for (int index : indices) {
+            if (index < 0 || index >= alphabet.size()) {
+                throw new IllegalArgumentException("Index " + index + " is out of bounds for the current alphabet of size " + alphabet.size() + ".");
+            }
+
+            // Get the symbol at the index
+            char symbol = alphabet.get(index);
+            output.append(symbol);
+
+            // Move the symbol to the front (mirroring the forward transform)
+            alphabet.remove(index);
+            alphabet.addFirst(symbol);
+        }
+        return output.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/compression/BurrowsWheelerTransformTest.java b/src/test/java/com/thealgorithms/compression/BurrowsWheelerTransformTest.java
new file mode 100644
index 000000000000..b6e10e0d796d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/compression/BurrowsWheelerTransformTest.java
@@ -0,0 +1,124 @@
+package com.thealgorithms.compression;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class BurrowsWheelerTransformTest {
+
+    @Test
+    public void testTransformAndInverseBanana() {
+        String original = "banana$";
+        BurrowsWheelerTransform.BWTResult expectedTransform = new BurrowsWheelerTransform.BWTResult("annb$aa", 4);
+
+        // Test forward transform
+        BurrowsWheelerTransform.BWTResult actualTransform = BurrowsWheelerTransform.transform(original);
+        assertEquals(expectedTransform, actualTransform);
+
+        // Test inverse transform
+        String reconstructed = BurrowsWheelerTransform.inverseTransform(actualTransform.transformed, actualTransform.originalIndex);
+        assertEquals(original, reconstructed);
+    }
+
+    @Test
+    public void testTransformAndInverseAbracadabra() {
+        String original = "abracadabra$";
+        BurrowsWheelerTransform.BWTResult expectedTransform = new BurrowsWheelerTransform.BWTResult("ard$rcaaaabb", 3);
+
+        // Test forward transform
+        BurrowsWheelerTransform.BWTResult actualTransform = BurrowsWheelerTransform.transform(original);
+        assertEquals(expectedTransform, actualTransform);
+
+        // Test inverse transform
+        String reconstructed = BurrowsWheelerTransform.inverseTransform(actualTransform.transformed, actualTransform.originalIndex);
+        assertEquals(original, reconstructed);
+    }
+
+    @Test
+    public void testTransformAndInverseSixMixPixFix() {
+        String original = "SIX.MIX.PIX.FIX$";
+        BurrowsWheelerTransform.BWTResult expectedTransform = new BurrowsWheelerTransform.BWTResult("XXXX.FPSM..$IIII", 11);
+
+        // Test forward transform
+        BurrowsWheelerTransform.BWTResult actualTransform = BurrowsWheelerTransform.transform(original);
+        assertEquals(expectedTransform, actualTransform);
+
+        // Test inverse transform
+        String reconstructed = BurrowsWheelerTransform.inverseTransform(actualTransform.transformed, actualTransform.originalIndex);
+        assertEquals(original, reconstructed);
+    }
+
+    @Test
+    public void testEmptyString() {
+        String original = "";
+        BurrowsWheelerTransform.BWTResult expectedTransform = new BurrowsWheelerTransform.BWTResult("", -1);
+
+        BurrowsWheelerTransform.BWTResult actualTransform = BurrowsWheelerTransform.transform(original);
+        assertEquals(expectedTransform, actualTransform);
+
+        String reconstructed = BurrowsWheelerTransform.inverseTransform(actualTransform.transformed, actualTransform.originalIndex);
+        assertEquals(original, reconstructed);
+    }
+
+    @Test
+    public void testSingleCharacter() {
+        String original = "a";
+        BurrowsWheelerTransform.BWTResult expectedTransform = new BurrowsWheelerTransform.BWTResult("a", 0);
+
+        BurrowsWheelerTransform.BWTResult actualTransform = BurrowsWheelerTransform.transform(original);
+        assertEquals(expectedTransform, actualTransform);
+
+        String reconstructed = BurrowsWheelerTransform.inverseTransform(actualTransform.transformed, actualTransform.originalIndex);
+        assertEquals(original, reconstructed);
+    }
+
+    @Test
+    public void testTransformNull() {
+        assertEquals(new BurrowsWheelerTransform.BWTResult("", -1), BurrowsWheelerTransform.transform(null));
+    }
+
+    @Test
+    public void testInverseTransformNullString() {
+        // bwtString == null
+        assertEquals("", BurrowsWheelerTransform.inverseTransform(null, 1));
+        // bwtString.isEmpty()
+        assertEquals("", BurrowsWheelerTransform.inverseTransform("", 0));
+    }
+
+    @Test
+    public void testInverseTransformIndexOutOfBounds() {
+        String bwt = "annb$aa";
+        int n = bwt.length(); // n = 7
+
+        // originalIndex >= n
+        assertThrows(IllegalArgumentException.class, () -> BurrowsWheelerTransform.inverseTransform(bwt, n));
+        assertThrows(IllegalArgumentException.class, () -> BurrowsWheelerTransform.inverseTransform(bwt, 8));
+
+        // originalIndex < 0
+        assertThrows(IllegalArgumentException.class, () -> BurrowsWheelerTransform.inverseTransform(bwt, -2));
+    }
+
+    @Test
+    public void testBWTResultHelpers() {
+        BurrowsWheelerTransform.BWTResult res1 = new BurrowsWheelerTransform.BWTResult("annb$aa", 4);
+        BurrowsWheelerTransform.BWTResult res2 = new BurrowsWheelerTransform.BWTResult("annb$aa", 4);
+        BurrowsWheelerTransform.BWTResult res3 = new BurrowsWheelerTransform.BWTResult("other", 4);
+        BurrowsWheelerTransform.BWTResult res4 = new BurrowsWheelerTransform.BWTResult("annb$aa", 1);
+
+        assertEquals(res1, res1);
+        assertEquals(res1, res2);
+        assertNotEquals(res1, null); // obj == null
+        assertNotEquals(res1, new Object()); // different class
+        assertNotEquals(res1, res3); // different transformed
+        assertNotEquals(res1, res4); // different originalIndex
+
+        assertEquals(res1.hashCode(), res2.hashCode());
+        assertNotEquals(res1.hashCode(), res3.hashCode());
+
+        assertTrue(res1.toString().contains("annb$aa"));
+        assertTrue(res1.toString().contains("originalIndex=4"));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/compression/MoveToFrontTest.java b/src/test/java/com/thealgorithms/compression/MoveToFrontTest.java
new file mode 100644
index 000000000000..42ef6c9cd675
--- /dev/null
+++ b/src/test/java/com/thealgorithms/compression/MoveToFrontTest.java
@@ -0,0 +1,92 @@
+package com.thealgorithms.compression;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class MoveToFrontTest {
+
+    @Test
+    public void testTransformAndInverseBananaExample() {
+        String original = "annb$aa";
+        String alphabet = "$abn";
+        List<Integer> expectedTransform = List.of(1, 3, 0, 3, 3, 3, 0);
+
+        // Test forward transform
+        List<Integer> actualTransform = MoveToFront.transform(original, alphabet);
+        assertEquals(expectedTransform, actualTransform);
+
+        // Test inverse transform
+        String reconstructed = MoveToFront.inverseTransform(actualTransform, alphabet);
+        assertEquals(original, reconstructed);
+    }
+
+    @Test
+    public void testTransformAndInverseCabaaExample() {
+        String original = "cabaa";
+        String alphabet = "abcdef";
+        List<Integer> expectedTransform = List.of(2, 1, 2, 1, 0);
+
+        // Test forward transform
+        List<Integer> actualTransform = MoveToFront.transform(original, alphabet);
+        assertEquals(expectedTransform, actualTransform);
+
+        // Test inverse transform
+        String reconstructed = MoveToFront.inverseTransform(actualTransform, alphabet);
+        assertEquals(original, reconstructed);
+    }
+
+    @Test
+    public void testEmptyInput() {
+        String original = "";
+        String alphabet = "abc";
+        List<Integer> expectedTransform = List.of();
+
+        List<Integer> actualTransform = MoveToFront.transform(original, alphabet);
+        assertEquals(expectedTransform, actualTransform);
+
+        String reconstructed = MoveToFront.inverseTransform(actualTransform, alphabet);
+        assertEquals(original, reconstructed);
+    }
+
+    @Test
+    public void testEmptyAlphabet() {
+        assertThrows(IllegalArgumentException.class, () -> MoveToFront.transform("abc", ""));
+
+        assertEquals("", MoveToFront.inverseTransform(List.of(1, 2), ""));
+    }
+
+    @Test
+    public void testSymbolNotInAlphabet() {
+        // 'd' is not in "abc"
+        assertThrows(IllegalArgumentException.class, () -> MoveToFront.transform("abd", "abc"));
+    }
+
+    @Test
+    public void testIndexOutOfBounds() {
+        // Index 5 is out of bounds for alphabet "abc"
+        // 1. test index >= alphabet.size()
+        assertThrows(IllegalArgumentException.class, () -> MoveToFront.inverseTransform(List.of(1, 2, 5), "abc"));
+
+        // 2. test index < 0
+        assertThrows(IllegalArgumentException.class, () -> MoveToFront.inverseTransform(List.of(1, -1, 2), "abc"));
+    }
+
+    @Test
+    public void testTransformNull() {
+        List<Integer> expected = List.of();
+        assertEquals(expected, MoveToFront.transform(null, "abc"));
+        assertThrows(IllegalArgumentException.class, () -> MoveToFront.transform("abc", null));
+    }
+
+    @Test
+    public void testInverseTransformNulls() {
+        // 1. test indices == null
+        assertEquals("", MoveToFront.inverseTransform(null, "abc"));
+
+        // 2. test initialAlphabet == null
+        assertEquals("", MoveToFront.inverseTransform(List.of(1, 2), null));
+    }
+}

From e21aee814ce393c8107f8f47ac161c19f7cac293 Mon Sep 17 00:00:00 2001
From: Priyanshu Kumar Singh <priyanshu1303d@gmail.com>
Date: Sat, 25 Oct 2025 20:48:15 +0530
Subject: [PATCH 1045/1338] [FEAT] Add Newton's Law of Gravitation algorithm
 (#6855)

Co-authored-by: Priyanshu1303d <priyanshu130d@gmail.com>
---
 .../thealgorithms/physics/Gravitation.java    | 66 +++++++++++++++
 .../physics/GravitationTest.java              | 83 +++++++++++++++++++
 2 files changed, 149 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/physics/Gravitation.java
 create mode 100644 src/test/java/com/thealgorithms/physics/GravitationTest.java

diff --git a/src/main/java/com/thealgorithms/physics/Gravitation.java b/src/main/java/com/thealgorithms/physics/Gravitation.java
new file mode 100644
index 000000000000..292fdc195f85
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/Gravitation.java
@@ -0,0 +1,66 @@
+package com.thealgorithms.physics;
+
+/**
+ * Implements Newton's Law of Universal Gravitation.
+ * Provides simple static methods to calculate gravitational force and circular orbit velocity.
+ *
+ * @author [Priyanshu Kumar Singh](https://github.com/Priyanshu1303d)
+ * @see <a href="https://en.wikipedia.org/wiki/Newton%27s_law_of_universal_gravitation">Wikipedia</a>
+ */
+public final class Gravitation {
+
+    /** Gravitational constant in m^3 kg^-1 s^-2 */
+    public static final double GRAVITATIONAL_CONSTANT = 6.67430e-11;
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private Gravitation() {
+    }
+
+    /**
+     * Calculates the gravitational force vector exerted by one body on another.
+     *
+     * @param m1 Mass of the first body (kg).
+     * @param x1 X-position of the first body (m).
+     * @param y1 Y-position of the first body (m).
+     * @param m2 Mass of the second body (kg).
+     * @param x2 X-position of the second body (m).
+     * @param y2 Y-position of the second body (m).
+     * @return A double array `[fx, fy]` representing the force vector on the second body.
+     */
+    public static double[] calculateGravitationalForce(double m1, double x1, double y1, double m2, double x2, double y2) {
+        double dx = x1 - x2;
+        double dy = y1 - y2;
+        double distanceSq = dx * dx + dy * dy;
+
+        // If bodies are at the same position, force is zero to avoid division by zero.
+        if (distanceSq == 0) {
+            return new double[] {0, 0};
+        }
+
+        double distance = Math.sqrt(distanceSq);
+        double forceMagnitude = GRAVITATIONAL_CONSTANT * m1 * m2 / distanceSq;
+
+        // Calculate the components of the force vector
+        double fx = forceMagnitude * (dx / distance);
+        double fy = forceMagnitude * (dy / distance);
+
+        return new double[] {fx, fy};
+    }
+
+    /**
+     * Calculates the speed required for a stable circular orbit.
+     *
+     * @param centralMass The mass of the central body (kg).
+     * @param radius The radius of the orbit (m).
+     * @return The orbital speed (m/s).
+     * @throws IllegalArgumentException if mass or radius are not positive.
+     */
+    public static double calculateCircularOrbitVelocity(double centralMass, double radius) {
+        if (centralMass <= 0 || radius <= 0) {
+            throw new IllegalArgumentException("Mass and radius must be positive.");
+        }
+        return Math.sqrt(GRAVITATIONAL_CONSTANT * centralMass / radius);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/GravitationTest.java b/src/test/java/com/thealgorithms/physics/GravitationTest.java
new file mode 100644
index 000000000000..9094e289e79a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/GravitationTest.java
@@ -0,0 +1,83 @@
+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the Gravitation utility class.
+ */
+final class GravitationTest {
+
+    // A small tolerance (delta) for comparing floating-point numbers
+    private static final double DELTA = 1e-9;
+    private static final double G = Gravitation.GRAVITATIONAL_CONSTANT;
+
+    @Test
+    @DisplayName("Test gravitational force between two bodies on the x-axis")
+    void testSimpleForceCalculation() {
+        // Force on body 2 should be F = G*1*1 / 1^2 = G, directed towards body 1 (negative x)
+        double[] forceOnB = Gravitation.calculateGravitationalForce(1.0, 0, 0, 1.0, 1, 0);
+        assertArrayEquals(new double[] {-G, 0.0}, forceOnB, DELTA);
+
+        // Force on body 1 should be equal and opposite (positive x)
+        double[] forceOnA = Gravitation.calculateGravitationalForce(1.0, 1, 0, 1.0, 0, 0);
+        assertArrayEquals(new double[] {G, 0.0}, forceOnA, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test gravitational force in a 2D plane")
+    void test2DForceCalculation() {
+        // Body 1 at (0,0) with mass 2kg
+        // Body 2 at (3,4) with mass 1kg
+        // Distance is sqrt(3^2 + 4^2) = 5 meters
+        double magnitude = 2.0 * G / 25.0; // G * 2 * 1 / 5^2
+        // Unit vector from 2 to 1 is (-3/5, -4/5)
+        double expectedFx = magnitude * -3.0 / 5.0; // -6G / 125
+        double expectedFy = magnitude * -4.0 / 5.0; // -8G / 125
+
+        double[] forceOnB = Gravitation.calculateGravitationalForce(2.0, 0, 0, 1.0, 3, 4);
+        assertArrayEquals(new double[] {expectedFx, expectedFy}, forceOnB, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test overlapping bodies should result in zero force")
+    void testOverlappingBodies() {
+        double[] force = Gravitation.calculateGravitationalForce(1000.0, 1.5, -2.5, 500.0, 1.5, -2.5);
+        assertArrayEquals(new double[] {0.0, 0.0}, force, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test circular orbit velocity with simple values")
+    void testCircularOrbitVelocity() {
+        // v = sqrt(G*1/1) = sqrt(G)
+        double velocity = Gravitation.calculateCircularOrbitVelocity(1.0, 1.0);
+        assertEquals(Math.sqrt(G), velocity, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test orbital velocity with real-world-ish values (LEO)")
+    void testEarthOrbitVelocity() {
+        // Mass of Earth ~5.972e24 kg
+        // Radius of LEO ~6,771,000 m (Earth radius + 400km)
+        double earthMass = 5.972e24;
+        double leoRadius = 6.771e6;
+        // FIX: Updated expected value to match the high-precision calculation
+        double expectedVelocity = 7672.4904;
+
+        double velocity = Gravitation.calculateCircularOrbitVelocity(earthMass, leoRadius);
+        assertEquals(expectedVelocity, velocity, 0.0001); // Use a larger delta for big numbers
+    }
+
+    @Test
+    @DisplayName("Test invalid inputs for orbital velocity throw exception")
+    void testInvalidOrbitalVelocityInputs() {
+        assertThrows(IllegalArgumentException.class, () -> Gravitation.calculateCircularOrbitVelocity(0, 100));
+        assertThrows(IllegalArgumentException.class, () -> Gravitation.calculateCircularOrbitVelocity(-1000, 100));
+        assertThrows(IllegalArgumentException.class, () -> Gravitation.calculateCircularOrbitVelocity(1000, 0));
+        assertThrows(IllegalArgumentException.class, () -> Gravitation.calculateCircularOrbitVelocity(1000, -100));
+    }
+}

From 252155630ecc1e7943f3c697f158f9bae4ca93d0 Mon Sep 17 00:00:00 2001
From: Priyanshu Kumar Singh <priyanshu1303d@gmail.com>
Date: Sun, 26 Oct 2025 01:42:45 +0530
Subject: [PATCH 1046/1338] [FEAT] Add general purpose Projectile Motion
 algorithm (Physics) (#6928)

[FEAT] Add general purpose Projectile Motion algorithm

Co-authored-by: Priyanshu1303d <priyanshu130d@gmail.com>
Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../physics/ProjectileMotion.java             | 96 +++++++++++++++++++
 .../physics/ProjectileMotionTest.java         | 69 +++++++++++++
 2 files changed, 165 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/physics/ProjectileMotion.java
 create mode 100644 src/test/java/com/thealgorithms/physics/ProjectileMotionTest.java

diff --git a/src/main/java/com/thealgorithms/physics/ProjectileMotion.java b/src/main/java/com/thealgorithms/physics/ProjectileMotion.java
new file mode 100644
index 000000000000..cfc79547922c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/ProjectileMotion.java
@@ -0,0 +1,96 @@
+package com.thealgorithms.physics;
+
+/**
+ *
+ * This implementation calculates the flight path of a projectile launched from any INITIAL HEIGHT.
+ * It is a more flexible version of the ground-to-ground model.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Projectile_motion">Wikipedia - Projectile Motion</a>
+ * @author [Priyanshu Kumar Singh](https://github.com/Priyanshu1303d)
+ */
+public final class ProjectileMotion {
+
+    private ProjectileMotion() {
+    }
+
+    /** Standard Earth gravity constant*/
+    private static final double GRAVITY = 9.80665;
+
+    /**
+     * A simple container for the results of a projectile motion calculation.
+     */
+    public static final class Result {
+        private final double timeOfFlight;
+        private final double horizontalRange;
+        private final double maxHeight;
+
+        public Result(double timeOfFlight, double horizontalRange, double maxHeight) {
+            this.timeOfFlight = timeOfFlight;
+            this.horizontalRange = horizontalRange;
+            this.maxHeight = maxHeight;
+        }
+
+        /** @return The total time the projectile is in the air (seconds). */
+        public double getTimeOfFlight() {
+            return timeOfFlight;
+        }
+
+        /** @return The total horizontal distance traveled (meters). */
+        public double getHorizontalRange() {
+            return horizontalRange;
+        }
+
+        /** @return The maximum vertical height from the ground (meters). */
+        public double getMaxHeight() {
+            return maxHeight;
+        }
+    }
+
+    /**
+     * Calculates projectile trajectory using standard Earth gravity.
+     *
+     * @param initialVelocity Initial speed of the projectile (m/s).
+     * @param launchAngleDegrees Launch angle from the horizontal (degrees).
+     * @param initialHeight Starting height of the projectile (m).
+     * @return A {@link Result} object with the trajectory data.
+     */
+    public static Result calculateTrajectory(double initialVelocity, double launchAngleDegrees, double initialHeight) {
+        return calculateTrajectory(initialVelocity, launchAngleDegrees, initialHeight, GRAVITY);
+    }
+
+    /**
+     * Calculates projectile trajectory with a custom gravity value.
+     *
+     * @param initialVelocity Initial speed (m/s). Must be non-negative.
+     * @param launchAngleDegrees Launch angle (degrees).
+     * @param initialHeight Starting height (m). Must be non-negative.
+     * @param gravity Acceleration due to gravity (m/s^2). Must be positive.
+     * @return A {@link Result} object with the trajectory data.
+     */
+    public static Result calculateTrajectory(double initialVelocity, double launchAngleDegrees, double initialHeight, double gravity) {
+        if (initialVelocity < 0 || initialHeight < 0 || gravity <= 0) {
+            throw new IllegalArgumentException("Velocity, height, and gravity must be non-negative, and gravity must be positive.");
+        }
+
+        double launchAngleRadians = Math.toRadians(launchAngleDegrees);
+        double initialVerticalVelocity = initialVelocity * Math.sin(launchAngleRadians); // Initial vertical velocity
+        double initialHorizontalVelocity = initialVelocity * Math.cos(launchAngleRadians); // Initial horizontal velocity
+
+        // Correctly calculate total time of flight using the quadratic formula for vertical motion.
+        // y(t) = y0 + initialVerticalVelocity*t - 0.5*g*t^2. We solve for t when y(t) = 0.
+        double totalTimeOfFlight = (initialVerticalVelocity + Math.sqrt(initialVerticalVelocity * initialVerticalVelocity + 2 * gravity * initialHeight)) / gravity;
+
+        // Calculate max height. If launched downwards, max height is the initial height.
+        double maxHeight;
+        if (initialVerticalVelocity > 0) {
+            double heightGained = initialVerticalVelocity * initialVerticalVelocity / (2 * gravity);
+            maxHeight = initialHeight + heightGained;
+        } else {
+            maxHeight = initialHeight;
+        }
+
+        double horizontalRange = initialHorizontalVelocity * totalTimeOfFlight;
+
+        return new Result(totalTimeOfFlight, horizontalRange, maxHeight);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/ProjectileMotionTest.java b/src/test/java/com/thealgorithms/physics/ProjectileMotionTest.java
new file mode 100644
index 000000000000..25e7cfa87f9e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/ProjectileMotionTest.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for the general-purpose ProjectileMotion calculator.
+ *
+ */
+final class ProjectileMotionTest {
+
+    private static final double DELTA = 1e-4; // Tolerance for comparing double values
+
+    @Test
+    @DisplayName("Test ground-to-ground launch (initial height is zero)")
+    void testGroundToGroundLaunch() {
+        ProjectileMotion.Result result = ProjectileMotion.calculateTrajectory(50, 30, 0);
+        assertEquals(5.0986, result.getTimeOfFlight(), DELTA);
+        assertEquals(220.7750, result.getHorizontalRange(), DELTA);
+        assertEquals(31.8661, result.getMaxHeight(), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test launch from an elevated position")
+    void testElevatedLaunch() {
+        ProjectileMotion.Result result = ProjectileMotion.calculateTrajectory(30, 45, 100);
+        assertEquals(7.1705, result.getTimeOfFlight(), DELTA);
+        assertEquals(152.1091, result.getHorizontalRange(), DELTA);
+        assertEquals(122.9436, result.getMaxHeight(), DELTA); // Final corrected value
+    }
+
+    @Test
+    @DisplayName("Test launch straight up (90 degrees)")
+    void testVerticalLaunch() {
+        ProjectileMotion.Result result = ProjectileMotion.calculateTrajectory(40, 90, 20);
+        assertEquals(8.6303, result.getTimeOfFlight(), DELTA);
+        assertEquals(0.0, result.getHorizontalRange(), DELTA);
+        assertEquals(101.5773, result.getMaxHeight(), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test horizontal launch from a height (0 degrees)")
+    void testHorizontalLaunch() {
+        ProjectileMotion.Result result = ProjectileMotion.calculateTrajectory(25, 0, 80);
+        assertEquals(4.0392, result.getTimeOfFlight(), DELTA);
+        assertEquals(100.9809, result.getHorizontalRange(), DELTA);
+        assertEquals(80.0, result.getMaxHeight(), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test downward launch from a height (negative angle)")
+    void testDownwardLaunchFromHeight() {
+        ProjectileMotion.Result result = ProjectileMotion.calculateTrajectory(20, -30, 100);
+        assertEquals(3.6100, result.getTimeOfFlight(), DELTA);
+        assertEquals(62.5268, result.getHorizontalRange(), DELTA);
+        assertEquals(100.0, result.getMaxHeight(), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test invalid arguments throw an exception")
+    void testInvalidInputs() {
+        assertThrows(IllegalArgumentException.class, () -> ProjectileMotion.calculateTrajectory(-10, 45, 100));
+        assertThrows(IllegalArgumentException.class, () -> ProjectileMotion.calculateTrajectory(10, 45, -100));
+        assertThrows(IllegalArgumentException.class, () -> ProjectileMotion.calculateTrajectory(10, 45, 100, 0));
+    }
+}

From 2da0465fe08d634093c89e4f29bf67be00082d50 Mon Sep 17 00:00:00 2001
From: Indolyn Yi <microindole@gmail.com>
Date: Sun, 26 Oct 2025 04:18:45 +0800
Subject: [PATCH 1047/1338] feat(geometry): Add Bentley-Ottmann algorithm for
 line segment intersection (#6871)

* feat(geometry): add Bentley-Ottmann line segment intersection algorithm

- Implement sweep-line algorithm for finding all intersection points
- Time complexity: O((n + k) log n) where n is segments, k is intersections
- Uses event queue (PriorityQueue) and status structure (TreeSet)
- Handles vertical/horizontal segments, collinear overlaps, and touching endpoints
- Includes comprehensive Javadoc with examples and references

* test(geometry): add comprehensive tests for Bentley-Ottmann algorithm

- 19 test cases covering typical, edge, and degenerate cases
- Tests include: single/multiple intersections, parallel segments, grid patterns
- Performance test with 100 random segments
- All tests validate correctness of intersection detection

* style(geometry): fix code style

* test(geometry): Achieve 100% test coverage for BentleyOttmann

* style(geometry): fix code style again

* fix: correct import order in BentleyOttmann

* fix(geometry): Resolve SpotBugs and PMD static analysis warnings

* Reorder import statements in BentleyOttmannTest

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../geometry/BentleyOttmann.java              | 423 ++++++++++++++++++
 .../geometry/BentleyOttmannTest.java          | 324 ++++++++++++++
 2 files changed, 747 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/geometry/BentleyOttmann.java
 create mode 100644 src/test/java/com/thealgorithms/geometry/BentleyOttmannTest.java

diff --git a/src/main/java/com/thealgorithms/geometry/BentleyOttmann.java b/src/main/java/com/thealgorithms/geometry/BentleyOttmann.java
new file mode 100644
index 000000000000..a11acb87dd7a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/geometry/BentleyOttmann.java
@@ -0,0 +1,423 @@
+package com.thealgorithms.geometry;
+
+import java.awt.geom.Point2D;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.NavigableSet;
+import java.util.Objects;
+import java.util.PriorityQueue;
+import java.util.Set;
+import java.util.SortedSet;
+import java.util.TreeSet;
+
+/**
+ * Implementation of the Bentley–Ottmann algorithm for finding all intersection
+ * points among a set of line segments in O((n + k) log n) time.
+ *
+ * <p>Uses a sweep-line approach with an event queue and status structure to
+ * efficiently detect intersections in 2D plane geometry.</p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Bentley%E2%80%93Ottmann_algorithm">
+ *      Bentley–Ottmann algorithm</a>
+ */
+public final class BentleyOttmann {
+
+    private BentleyOttmann() {
+    }
+
+    private static final double EPS = 1e-9;
+    private static double currentSweepX;
+
+    /**
+     * Represents a line segment with two endpoints.
+     */
+    public static class Segment {
+        final Point2D.Double p1;
+        final Point2D.Double p2;
+        final int id; // Unique identifier for each segment
+
+        Segment(Point2D.Double p1, Point2D.Double p2) {
+            this.p1 = p1;
+            this.p2 = p2;
+            this.id = segmentCounter++;
+        }
+
+        private static int segmentCounter = 0;
+
+        /**
+         * Computes the y-coordinate of this segment at a given x value.
+         */
+        double getY(double x) {
+            if (Math.abs(p2.x - p1.x) < EPS) {
+                // Vertical segment: return midpoint y
+                return (p1.y + p2.y) / 2.0;
+            }
+            double t = (x - p1.x) / (p2.x - p1.x);
+            return p1.y + t * (p2.y - p1.y);
+        }
+
+        Point2D.Double leftPoint() {
+            return p1.x < p2.x ? p1 : p1.x > p2.x ? p2 : p1.y < p2.y ? p1 : p2;
+        }
+
+        Point2D.Double rightPoint() {
+            return p1.x > p2.x ? p1 : p1.x < p2.x ? p2 : p1.y > p2.y ? p1 : p2;
+        }
+
+        @Override
+        public String toString() {
+            return String.format("S%d[(%.2f, %.2f), (%.2f, %.2f)]", id, p1.x, p1.y, p2.x, p2.y);
+        }
+    }
+
+    /**
+     * Event types for the sweep line algorithm.
+     */
+    private enum EventType { START, END, INTERSECTION }
+
+    /**
+     * Represents an event in the event queue.
+     */
+    private static class Event implements Comparable<Event> {
+        final Point2D.Double point;
+        final EventType type;
+        final Set<Segment> segments; // Segments involved in this event
+
+        Event(Point2D.Double point, EventType type) {
+            this.point = point;
+            this.type = type;
+            this.segments = new HashSet<>();
+        }
+
+        void addSegment(Segment s) {
+            segments.add(s);
+        }
+
+        @Override
+        public int compareTo(Event other) {
+            // Sort by x-coordinate, then by y-coordinate
+            int cmp = Double.compare(this.point.x, other.point.x);
+            if (cmp == 0) {
+                cmp = Double.compare(this.point.y, other.point.y);
+            }
+            if (cmp == 0) {
+                // Process END events before START events at same point
+                cmp = this.type.compareTo(other.type);
+            }
+            return cmp;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (!(o instanceof Event e)) {
+                return false;
+            }
+            return pointsEqual(this.point, e.point);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(Math.round(point.x * 1e6), Math.round(point.y * 1e6));
+        }
+    }
+
+    /**
+     * Comparator for segments in the status structure (sweep line).
+     * Orders segments by their y-coordinate at the current sweep line position.
+     */
+    private static final class StatusComparator implements Comparator<Segment> {
+        @Override
+        public int compare(Segment s1, Segment s2) {
+            if (s1.id == s2.id) {
+                return 0;
+            }
+
+            double y1 = s1.getY(currentSweepX);
+            double y2 = s2.getY(currentSweepX);
+
+            int cmp = Double.compare(y1, y2);
+            if (Math.abs(y1 - y2) < EPS) {
+                // If y-coordinates are equal, use segment id for consistency
+                return Integer.compare(s1.id, s2.id);
+            }
+            return cmp;
+        }
+    }
+
+    /**
+     * Finds all intersection points among a set of line segments.
+     *
+     * <p>An intersection point is reported when two or more segments cross or touch.
+     * For overlapping segments, only actual crossing/touching points are reported,
+     * not all points along the overlap.</p>
+     *
+     * @param segments list of line segments represented as pairs of points
+     * @return a set of intersection points where segments meet or cross
+     * @throws IllegalArgumentException if the list is null or contains null points
+     */
+    public static Set<Point2D.Double> findIntersections(List<Segment> segments) {
+        if (segments == null) {
+            throw new IllegalArgumentException("Segment list must not be null");
+        }
+
+        Segment.segmentCounter = 0; // Reset counter
+        Set<Point2D.Double> intersections = new HashSet<>();
+        PriorityQueue<Event> eventQueue = new PriorityQueue<>();
+        TreeSet<Segment> status = new TreeSet<>(new StatusComparator());
+        Map<Point2D.Double, Event> eventMap = new HashMap<>();
+
+        // Initialize event queue with segment start and end points
+        for (Segment s : segments) {
+            Point2D.Double left = s.leftPoint();
+            Point2D.Double right = s.rightPoint();
+
+            Event startEvent = getOrCreateEvent(eventMap, left, EventType.START);
+            startEvent.addSegment(s);
+
+            Event endEvent = getOrCreateEvent(eventMap, right, EventType.END);
+            endEvent.addSegment(s);
+        }
+
+        // Add all unique events to the queue
+        for (Event e : eventMap.values()) {
+            if (!e.segments.isEmpty()) {
+                eventQueue.add(e);
+            }
+        }
+
+        // Process events
+        while (!eventQueue.isEmpty()) {
+            Event event = eventQueue.poll();
+            currentSweepX = event.point.x;
+
+            handleEvent(event, status, eventQueue, eventMap, intersections);
+        }
+
+        return intersections;
+    }
+
+    private static Event getOrCreateEvent(Map<Point2D.Double, Event> eventMap, Point2D.Double point, EventType type) {
+        // Find existing event at this point
+        for (Map.Entry<Point2D.Double, Event> entry : eventMap.entrySet()) {
+            if (pointsEqual(entry.getKey(), point)) {
+                return entry.getValue();
+            }
+        }
+        // Create new event
+        Event event = new Event(point, type);
+        eventMap.put(point, event);
+        return event;
+    }
+
+    private static void handleEvent(Event event, TreeSet<Segment> status, PriorityQueue<Event> eventQueue, Map<Point2D.Double, Event> eventMap, Set<Point2D.Double> intersections) {
+        Point2D.Double p = event.point;
+        Set<Segment> segmentsAtPoint = new HashSet<>(event.segments);
+
+        // Check segments in status structure (much smaller than allSegments)
+        for (Segment s : status) {
+            if (pointsEqual(s.p1, p) || pointsEqual(s.p2, p) || (onSegment(s, p) && !pointsEqual(s.p1, p) && !pointsEqual(s.p2, p))) {
+                segmentsAtPoint.add(s);
+            }
+        }
+
+        // If 2 or more segments meet at this point, it's an intersection
+        if (segmentsAtPoint.size() >= 2) {
+            intersections.add(p);
+        }
+
+        // Categorize segments
+        Set<Segment> upperSegs = new HashSet<>(); // Segments starting at p
+        Set<Segment> lowerSegs = new HashSet<>(); // Segments ending at p
+        Set<Segment> containingSegs = new HashSet<>(); // Segments containing p in interior
+
+        for (Segment s : segmentsAtPoint) {
+            if (pointsEqual(s.leftPoint(), p)) {
+                upperSegs.add(s);
+            } else if (pointsEqual(s.rightPoint(), p)) {
+                lowerSegs.add(s);
+            } else {
+                containingSegs.add(s);
+            }
+        }
+
+        // Remove ending segments and segments containing p from status
+        status.removeAll(lowerSegs);
+        status.removeAll(containingSegs);
+
+        // Update sweep line position slightly past the event
+        currentSweepX = p.x + EPS;
+
+        // Add starting segments and re-add containing segments
+        status.addAll(upperSegs);
+        status.addAll(containingSegs);
+
+        if (upperSegs.isEmpty() && containingSegs.isEmpty()) {
+            // Find neighbors and check for new intersections
+            Segment sl = getNeighbor(status, lowerSegs, true);
+            Segment sr = getNeighbor(status, lowerSegs, false);
+            if (sl != null && sr != null) {
+                findNewEvent(sl, sr, p, eventQueue, eventMap);
+            }
+        } else {
+            Set<Segment> unionSegs = new HashSet<>(upperSegs);
+            unionSegs.addAll(containingSegs);
+
+            Segment leftmost = getLeftmost(unionSegs, status);
+            Segment rightmost = getRightmost(unionSegs, status);
+
+            if (leftmost != null) {
+                Segment sl = status.lower(leftmost);
+                if (sl != null) {
+                    findNewEvent(sl, leftmost, p, eventQueue, eventMap);
+                }
+            }
+
+            if (rightmost != null) {
+                Segment sr = status.higher(rightmost);
+                if (sr != null) {
+                    findNewEvent(rightmost, sr, p, eventQueue, eventMap);
+                }
+            }
+        }
+    }
+
+    private static Segment getNeighbor(NavigableSet<Segment> status, Set<Segment> removed, boolean lower) {
+        if (removed.isEmpty()) {
+            return null;
+        }
+        Segment ref = removed.iterator().next();
+        return lower ? status.lower(ref) : status.higher(ref);
+    }
+
+    private static Segment getLeftmost(Set<Segment> segments, SortedSet<Segment> status) {
+        Segment leftmost = null;
+        for (Segment s : segments) {
+            if (leftmost == null || Objects.requireNonNull(status.comparator()).compare(s, leftmost) < 0) {
+                leftmost = s;
+            }
+        }
+        return leftmost;
+    }
+
+    private static Segment getRightmost(Set<Segment> segments, SortedSet<Segment> status) {
+        Segment rightmost = null;
+        for (Segment s : segments) {
+            if (status.comparator() != null && (rightmost == null || status.comparator().compare(s, rightmost) > 0)) {
+                rightmost = s;
+            }
+        }
+        return rightmost;
+    }
+
+    private static void findNewEvent(Segment s1, Segment s2, Point2D.Double currentPoint, PriorityQueue<Event> eventQueue, Map<Point2D.Double, Event> eventMap) {
+        Point2D.Double intersection = getIntersection(s1, s2);
+
+        if (intersection != null && intersection.x > currentPoint.x - EPS && !pointsEqual(intersection, currentPoint)) {
+
+            // Check if event already exists
+            boolean exists = false;
+            for (Map.Entry<Point2D.Double, Event> entry : eventMap.entrySet()) {
+                if (pointsEqual(entry.getKey(), intersection)) {
+                    exists = true;
+                    Event existingEvent = entry.getValue();
+                    existingEvent.addSegment(s1);
+                    existingEvent.addSegment(s2);
+                    break;
+                }
+            }
+
+            if (!exists) {
+                Event newEvent = new Event(intersection, EventType.INTERSECTION);
+                newEvent.addSegment(s1);
+                newEvent.addSegment(s2);
+                eventMap.put(intersection, newEvent);
+                eventQueue.add(newEvent);
+            }
+        }
+    }
+
+    private static Point2D.Double getIntersection(Segment s1, Segment s2) {
+        double x1 = s1.p1.x;
+        double y1 = s1.p1.y;
+        double x2 = s1.p2.x;
+        double y2 = s1.p2.y;
+        double x3 = s2.p1.x;
+        double y3 = s2.p1.y;
+        double x4 = s2.p2.x;
+        double y4 = s2.p2.y;
+
+        double denom = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);
+
+        if (Math.abs(denom) < EPS) {
+            // Parallel or collinear
+            if (areCollinear(s1, s2)) {
+                // For collinear segments, check if they overlap
+                // Return any overlapping point
+                List<Point2D.Double> overlapPoints = new ArrayList<>();
+
+                if (onSegment(s1, s2.p1)) {
+                    overlapPoints.add(s2.p1);
+                }
+                if (onSegment(s1, s2.p2)) {
+                    overlapPoints.add(s2.p2);
+                }
+                if (onSegment(s2, s1.p1)) {
+                    overlapPoints.add(s1.p1);
+                }
+                if (onSegment(s2, s1.p2)) {
+                    overlapPoints.add(s1.p2);
+                }
+
+                // Remove duplicates and return the first point
+                if (!overlapPoints.isEmpty()) {
+                    // Find the point that's not an endpoint of both segments
+                    for (Point2D.Double pt : overlapPoints) {
+                        boolean isS1Endpoint = pointsEqual(pt, s1.p1) || pointsEqual(pt, s1.p2);
+                        boolean isS2Endpoint = pointsEqual(pt, s2.p1) || pointsEqual(pt, s2.p2);
+
+                        // If it's an endpoint of both, it's a touching point
+                        if (isS1Endpoint && isS2Endpoint) {
+                            return pt;
+                        }
+                    }
+                    // Return the first overlap point
+                    return overlapPoints.getFirst();
+                }
+            }
+            return null;
+        }
+
+        double t = ((x1 - x3) * (y3 - y4) - (y1 - y3) * (x3 - x4)) / denom;
+        double u = -((x1 - x2) * (y1 - y3) - (y1 - y2) * (x1 - x3)) / denom;
+
+        if (t >= -EPS && t <= 1 + EPS && u >= -EPS && u <= 1 + EPS) {
+            double px = x1 + t * (x2 - x1);
+            double py = y1 + t * (y2 - y1);
+            return new Point2D.Double(px, py);
+        }
+
+        return null;
+    }
+
+    private static boolean areCollinear(Segment s1, Segment s2) {
+        double cross1 = crossProduct(s1.p1, s1.p2, s2.p1);
+        double cross2 = crossProduct(s1.p1, s1.p2, s2.p2);
+        return Math.abs(cross1) < EPS && Math.abs(cross2) < EPS;
+    }
+
+    private static double crossProduct(Point2D.Double a, Point2D.Double b, Point2D.Double c) {
+        return (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
+    }
+
+    private static boolean onSegment(Segment s, Point2D.Double p) {
+        return p.x >= Math.min(s.p1.x, s.p2.x) - EPS && p.x <= Math.max(s.p1.x, s.p2.x) + EPS && p.y >= Math.min(s.p1.y, s.p2.y) - EPS && p.y <= Math.max(s.p1.y, s.p2.y) + EPS && Math.abs(crossProduct(s.p1, s.p2, p)) < EPS;
+    }
+
+    private static boolean pointsEqual(Point2D.Double p1, Point2D.Double p2) {
+        return Math.abs(p1.x - p2.x) < EPS && Math.abs(p1.y - p2.y) < EPS;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/geometry/BentleyOttmannTest.java b/src/test/java/com/thealgorithms/geometry/BentleyOttmannTest.java
new file mode 100644
index 000000000000..99240566a2f3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/geometry/BentleyOttmannTest.java
@@ -0,0 +1,324 @@
+package com.thealgorithms.geometry;
+
+import java.awt.geom.Point2D;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+import java.util.Set;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Comprehensive unit tests for {@link BentleyOttmann}.
+ *
+ * <p>This test suite validates the correctness of the Bentley–Ottmann algorithm
+ * implementation by checking intersection points between multiple line segment configurations.</p>
+ *
+ * <p>Test cases include typical, edge, degenerate geometrical setups, and performance tests.</p>
+ */
+public class BentleyOttmannTest {
+
+    private static final double EPS = 1e-6;
+
+    @Test
+    void testSingleIntersection() {
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(1, 1, 5, 5), newSegment(1, 5, 5, 1));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertEquals(1, intersections.size());
+        Assertions.assertTrue(containsPoint(intersections, 3.0, 3.0));
+    }
+
+    @Test
+    void testVerticalIntersection() {
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(3, 0, 3, 6), newSegment(1, 1, 5, 5));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertEquals(1, intersections.size());
+        Assertions.assertTrue(containsPoint(intersections, 3.0, 3.0));
+    }
+
+    @Test
+    void testNoIntersection() {
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 0, 1, 1), newSegment(2, 2, 3, 3));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertTrue(intersections.isEmpty());
+    }
+
+    @Test
+    void testCoincidentSegments() {
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(1, 1, 5, 5), newSegment(1, 1, 5, 5));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+
+        Assertions.assertEquals(2, intersections.size(), "Two identical segments should report 2 intersection points (both endpoints)");
+        Assertions.assertTrue(containsPoint(intersections, 1.0, 1.0));
+        Assertions.assertTrue(containsPoint(intersections, 5.0, 5.0));
+    }
+
+    @Test
+    void testHorizontalIntersection() {
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 2, 4, 2), newSegment(2, 0, 2, 4));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertTrue(containsPoint(intersections, 2.0, 2.0));
+    }
+
+    @Test
+    void testEmptyList() {
+        List<BentleyOttmann.Segment> segments = List.of();
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertTrue(intersections.isEmpty());
+    }
+
+    @Test
+    void testSingleSegment() {
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 0, 5, 5));
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertTrue(intersections.isEmpty());
+    }
+
+    @Test
+    void testNullListThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> BentleyOttmann.findIntersections(null));
+    }
+
+    @Test
+    void testParallelSegments() {
+        // Test 1: Parallel diagonal segments
+        List<BentleyOttmann.Segment> diagonalSegments = List.of(newSegment(0, 0, 4, 4), newSegment(1, 0, 5, 4), newSegment(2, 0, 6, 4));
+        Assertions.assertTrue(BentleyOttmann.findIntersections(diagonalSegments).isEmpty());
+
+        // Test 2: Parallel vertical segments
+        List<BentleyOttmann.Segment> verticalSegments = List.of(newSegment(1, 0, 1, 5), newSegment(2, 0, 2, 5), newSegment(3, 0, 3, 5));
+        Assertions.assertTrue(BentleyOttmann.findIntersections(verticalSegments).isEmpty());
+
+        // Test 3: Parallel horizontal segments
+        List<BentleyOttmann.Segment> horizontalSegments = List.of(newSegment(0, 1, 5, 1), newSegment(0, 2, 5, 2), newSegment(0, 3, 5, 3));
+        Assertions.assertTrue(BentleyOttmann.findIntersections(horizontalSegments).isEmpty());
+    }
+
+    @Test
+    void testTouchingEndpoints() {
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 0, 2, 2), newSegment(2, 2, 4, 0));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertEquals(1, intersections.size());
+        Assertions.assertTrue(containsPoint(intersections, 2.0, 2.0));
+    }
+
+    @Test
+    void testOverlappingCollinearSegments() {
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 0, 4, 4), newSegment(2, 2, 6, 6));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        // Overlapping collinear segments share the point (2,2) where second starts
+        // and (4,4) where first ends - at least one should be detected
+        Assertions.assertFalse(intersections.isEmpty(), "Should find at least one overlap point");
+        Assertions.assertTrue(containsPoint(intersections, 2.0, 2.0) || containsPoint(intersections, 4.0, 4.0), "Should contain either (2,2) or (4,4)");
+    }
+
+    @Test
+    void testMultipleSegmentsAtOnePoint() {
+        // Star pattern: 4 segments meeting at (2, 2)
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 2, 4, 2), // horizontal
+            newSegment(2, 0, 2, 4), // vertical
+            newSegment(0, 0, 4, 4), // diagonal /
+            newSegment(0, 4, 4, 0) // diagonal \
+        );
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertTrue(containsPoint(intersections, 2.0, 2.0));
+        // All segments meet at (2, 2), so should be reported once
+        Assertions.assertEquals(1, intersections.size());
+    }
+
+    @Test
+    void testGridPattern() {
+        // 3x3 grid: should have 9 intersection points
+        List<BentleyOttmann.Segment> segments = new ArrayList<>();
+
+        // Vertical lines at x = 0, 1, 2
+        for (int i = 0; i <= 2; i++) {
+            segments.add(newSegment(i, 0, i, 2));
+        }
+
+        // Horizontal lines at y = 0, 1, 2
+        for (int i = 0; i <= 2; i++) {
+            segments.add(newSegment(0, i, 2, i));
+        }
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+
+        // Each vertical line crosses each horizontal line
+        // 3 vertical × 3 horizontal = 9 intersections
+        Assertions.assertEquals(9, intersections.size(), "3x3 grid should have 9 intersections");
+
+        // Verify all grid points are present
+        for (int x = 0; x <= 2; x++) {
+            for (int y = 0; y <= 2; y++) {
+                Assertions.assertTrue(containsPoint(intersections, x, y), String.format("Grid point (%d, %d) should be present", x, y));
+            }
+        }
+    }
+
+    @Test
+    void testTriangleIntersections() {
+        // Three segments forming a triangle
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 0, 4, 0), // base
+            newSegment(0, 0, 2, 3), // left side
+            newSegment(4, 0, 2, 3) // right side
+        );
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        // Triangle vertices are intersections
+        Assertions.assertTrue(containsPoint(intersections, 0.0, 0.0));
+        Assertions.assertTrue(containsPoint(intersections, 4.0, 0.0));
+        Assertions.assertTrue(containsPoint(intersections, 2.0, 3.0));
+        Assertions.assertEquals(3, intersections.size());
+    }
+
+    @Test
+    void testCrossingDiagonals() {
+        // X pattern with multiple crossings
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 0, 10, 10), newSegment(0, 10, 10, 0), newSegment(5, 0, 5, 10), newSegment(0, 5, 10, 5));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertTrue(containsPoint(intersections, 5.0, 5.0), "Center point should be present");
+        Assertions.assertEquals(1, intersections.size());
+    }
+
+    @Test
+    void testVerySmallSegments() {
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0.001, 0.001, 0.002, 0.002), newSegment(0.001, 0.002, 0.002, 0.001));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertEquals(1, intersections.size());
+        Assertions.assertTrue(containsPoint(intersections, 0.0015, 0.0015));
+    }
+
+    @Test
+    void testSegmentsShareCommonPoint() {
+        List<BentleyOttmann.Segment> segmentsSameStart = List.of(newSegment(0, 0, 4, 4), newSegment(0, 0, 4, -4), newSegment(0, 0, -4, 4));
+
+        Set<Point2D.Double> intersectionsSameStart = BentleyOttmann.findIntersections(segmentsSameStart);
+        Assertions.assertTrue(containsPoint(intersectionsSameStart, 0.0, 0.0));
+        List<BentleyOttmann.Segment> segmentsSameEnd = List.of(newSegment(0, 0, 4, 4), newSegment(8, 4, 4, 4), newSegment(4, 8, 4, 4));
+
+        Set<Point2D.Double> intersectionsSameEnd = BentleyOttmann.findIntersections(segmentsSameEnd);
+        Assertions.assertTrue(containsPoint(intersectionsSameEnd, 4.0, 4.0));
+    }
+
+    @Test
+    void testSegmentsAtAngles() {
+        // Segments at 45, 90, 135 degrees
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 2, 4, 2), // horizontal
+            newSegment(2, 0, 2, 4), // vertical
+            newSegment(0, 0, 4, 4), // 45 degrees
+            newSegment(0, 4, 4, 0) // 135 degrees
+        );
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertTrue(containsPoint(intersections, 2.0, 2.0));
+    }
+
+    @Test
+    void testPerformanceWithManySegments() {
+        // Generate 100 random segments
+        Random random = new Random(42); // Fixed seed for reproducibility
+        List<BentleyOttmann.Segment> segments = new ArrayList<>();
+
+        for (int i = 0; i < 100; i++) {
+            double x1 = random.nextDouble() * 100;
+            double y1 = random.nextDouble() * 100;
+            double x2 = random.nextDouble() * 100;
+            double y2 = random.nextDouble() * 100;
+            segments.add(newSegment(x1, y1, x2, y2));
+        }
+
+        long startTime = System.currentTimeMillis();
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        long endTime = System.currentTimeMillis();
+
+        long duration = endTime - startTime;
+
+        // Should complete in reasonable time (< 1 second for 100 segments)
+        Assertions.assertTrue(duration < 1000, "Algorithm should complete in less than 1 second for 100 segments. Took: " + duration + "ms");
+
+        // Just verify it returns a valid result
+        Assertions.assertNotNull(intersections);
+        System.out.println("Performance test: 100 segments processed in " + duration + "ms, found " + intersections.size() + " intersections");
+    }
+
+    @Test
+    void testIssueExample() {
+        // Example from the GitHub issue
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(1, 1, 5, 5), // Segment A
+            newSegment(1, 5, 5, 1), // Segment B
+            newSegment(3, 0, 3, 6) // Segment C
+        );
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+
+        // Expected output: [(3, 3)]
+        Assertions.assertEquals(1, intersections.size(), "Should find exactly one intersection");
+        Assertions.assertTrue(containsPoint(intersections, 3.0, 3.0), "Intersection should be at (3, 3)");
+    }
+
+    @Test
+    void testEventTypeOrdering() {
+        // Multiple events at the same point with different types
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(2, 2, 6, 2), // ends at (2,2)
+            newSegment(0, 2, 2, 2), // ends at (2,2)
+            newSegment(2, 2, 2, 6), // starts at (2,2)
+            newSegment(2, 0, 2, 2) // ends at (2,2)
+        );
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertTrue(containsPoint(intersections, 2.0, 2.0));
+    }
+
+    @Test
+    void testCollinearOverlapWithInteriorPoint() {
+        // Test collinear segments where one segment's interior overlaps another
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 0, 6, 6), newSegment(2, 2, 4, 4));
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+
+        // Should find at least one overlap point (where segments touch/overlap)
+        Assertions.assertFalse(intersections.isEmpty(), "Should find overlap points for collinear segments");
+        Assertions.assertTrue(containsPoint(intersections, 2.0, 2.0) || containsPoint(intersections, 4.0, 4.0), "Should contain overlap boundary point");
+    }
+
+    @Test
+    void testCollinearTouchingAtBothEndpoints() {
+        // Test collinear segments that touch at both endpoints
+        // This triggers the "endpoint of both" logic (line 354-355)
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 0, 4, 4), newSegment(4, 4, 8, 8));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+        Assertions.assertEquals(1, intersections.size());
+        Assertions.assertTrue(containsPoint(intersections, 4.0, 4.0), "Should find touching point");
+    }
+
+    @Test
+    void testCollinearOverlapPartialInterior() {
+        // Test case where segments overlap but one point is inside, one is endpoint
+        List<BentleyOttmann.Segment> segments = List.of(newSegment(0, 0, 5, 5), newSegment(3, 3, 7, 7));
+
+        Set<Point2D.Double> intersections = BentleyOttmann.findIntersections(segments);
+
+        // Should detect the overlap region
+        Assertions.assertFalse(intersections.isEmpty());
+        // The algorithm should return at least one of the boundary points
+        Assertions.assertTrue(containsPoint(intersections, 3.0, 3.0) || containsPoint(intersections, 5.0, 5.0));
+    }
+
+    private static BentleyOttmann.Segment newSegment(double x1, double y1, double x2, double y2) {
+        return new BentleyOttmann.Segment(new Point2D.Double(x1, y1), new Point2D.Double(x2, y2));
+    }
+
+    private static boolean containsPoint(Set<Point2D.Double> points, double x, double y) {
+        return points.stream().anyMatch(p -> Math.abs(p.x - x) < EPS && Math.abs(p.y - y) < EPS);
+    }
+}

From 0cdbc584273eac356820abb63fac4946cffbab4d Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Date: Sun, 26 Oct 2025 10:00:37 +0100
Subject: [PATCH 1048/1338] chore: add workflow to close stale PRs with failed
 workflows (#6927)

---
 .github/workflows/close-failed-prs.yml | 80 ++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 .github/workflows/close-failed-prs.yml

diff --git a/.github/workflows/close-failed-prs.yml b/.github/workflows/close-failed-prs.yml
new file mode 100644
index 000000000000..8e2bd86a7e20
--- /dev/null
+++ b/.github/workflows/close-failed-prs.yml
@@ -0,0 +1,80 @@
+name: Close stale PRs with failed workflows
+
+on:
+  schedule:
+    - cron: '0 3 * * *' # runs daily at 03:00 UTC
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
+
+jobs:
+  close-stale:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Close stale PRs
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const mainBranches = ['main', 'master'];
+            const cutoffDays = 14;
+            const cutoff = new Date();
+            cutoff.setDate(cutoff.getDate() - cutoffDays);
+
+            const { data: prs } = await github.rest.pulls.list({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              state: 'open',
+              per_page: 100
+            });
+
+            for (const pr of prs) {
+              const updated = new Date(pr.updated_at);
+              if (updated > cutoff) continue;
+
+              const commits = await github.paginate(github.rest.pulls.listCommits, {
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                pull_number: pr.number,
+                per_page: 100
+              });
+
+              const meaningfulCommits = commits.filter(c => {
+                const msg = c.commit.message.toLowerCase();
+                const isMergeFromMain = mainBranches.some(branch =>
+                  msg.startsWith(`merge branch '${branch}'`) ||
+                  msg.includes(`merge remote-tracking branch '${branch}'`)
+                );
+                return !isMergeFromMain;
+              });
+
+              const { data: checks } = await github.rest.checks.listForRef({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                ref: pr.head.sha
+              });
+
+              const hasFailed = checks.check_runs.some(c => c.conclusion === 'failure');
+              const allCompleted = checks.check_runs.every(c => c.status === 'completed');
+
+              if (meaningfulCommits.length === 0 && hasFailed && allCompleted) {
+                console.log(`Closing PR #${pr.number} (${pr.title})`);
+
+                await github.rest.issues.createComment({
+                  owner: context.repo.owner,
+                  repo: context.repo.repo,
+                  issue_number: pr.number,
+                  body: `This pull request has been automatically closed because its workflows failed and it has been inactive for more than ${cutoffDays} days. Please fix the workflows and reopen if you'd like to continue. Merging from main/master alone does not count as activity.`
+                });
+
+                await github.rest.pulls.update({
+                  owner: context.repo.owner,
+                  repo: context.repo.repo,
+                  pull_number: pr.number,
+                  state: 'closed'
+                });
+              }
+            }
\ No newline at end of file

From a4cf6e36f4156efdb37eaf38af9f88e1718c2fef Mon Sep 17 00:00:00 2001
From: Krishna <satyasaikrishnareddy41@gmail.com>
Date: Sun, 26 Oct 2025 14:35:55 +0530
Subject: [PATCH 1049/1338] test: Add comprehensive tests for JugglerSequence
 (#6947)

* test: Add comprehensive tests for JugglerSequence

- Added tests for input values 1, 2, 3, and 9
- Tests verify correct sequence output
- Improves code coverage for maths package

* fix: Format JugglerSequenceTest
---
 .../maths/JugglerSequenceTest.java            | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/maths/JugglerSequenceTest.java

diff --git a/src/test/java/com/thealgorithms/maths/JugglerSequenceTest.java b/src/test/java/com/thealgorithms/maths/JugglerSequenceTest.java
new file mode 100644
index 000000000000..9f3e80eee2b6
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/JugglerSequenceTest.java
@@ -0,0 +1,42 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import org.junit.jupiter.api.Test;
+
+class JugglerSequenceTest {
+
+    @Test
+    void testJugglerSequenceWithThree() {
+        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outContent));
+        JugglerSequence.jugglerSequence(3);
+        assertEquals("3,5,11,36,6,2,1\n", outContent.toString());
+    }
+
+    @Test
+    void testJugglerSequenceWithTwo() {
+        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outContent));
+        JugglerSequence.jugglerSequence(2);
+        assertEquals("2,1\n", outContent.toString());
+    }
+
+    @Test
+    void testJugglerSequenceWithNine() {
+        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outContent));
+        JugglerSequence.jugglerSequence(9);
+        assertEquals("9,27,140,11,36,6,2,1\n", outContent.toString());
+    }
+
+    @Test
+    void testJugglerSequenceWithOne() {
+        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outContent));
+        JugglerSequence.jugglerSequence(1);
+        assertEquals("1\n", outContent.toString());
+    }
+}

From ae2e40acab4d0735b503b9ded8fc05a9275f2a9e Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Date: Sun, 26 Oct 2025 17:02:31 +0100
Subject: [PATCH 1050/1338] Enhance stale PR auto-close to handle failed
 workflows (#6951)

* chore: add workflow to close stale PRs with failed workflows

* Include workflow failures when closing stale PRs
---
 .github/workflows/close-failed-prs.yml | 164 ++++++++++++++++++-------
 1 file changed, 119 insertions(+), 45 deletions(-)

diff --git a/.github/workflows/close-failed-prs.yml b/.github/workflows/close-failed-prs.yml
index 8e2bd86a7e20..5d54eea07821 100644
--- a/.github/workflows/close-failed-prs.yml
+++ b/.github/workflows/close-failed-prs.yml
@@ -24,57 +24,131 @@ jobs:
             const cutoff = new Date();
             cutoff.setDate(cutoff.getDate() - cutoffDays);
 
-            const { data: prs } = await github.rest.pulls.list({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              state: 'open',
-              per_page: 100
-            });
-
-            for (const pr of prs) {
-              const updated = new Date(pr.updated_at);
-              if (updated > cutoff) continue;
-
-              const commits = await github.paginate(github.rest.pulls.listCommits, {
+            console.log(`Checking PRs older than: ${cutoff.toISOString()}`);
+
+            try {
+              const { data: prs } = await github.rest.pulls.list({
                 owner: context.repo.owner,
                 repo: context.repo.repo,
-                pull_number: pr.number,
+                state: 'open',
+                sort: 'updated',
+                direction: 'asc',
                 per_page: 100
               });
 
-              const meaningfulCommits = commits.filter(c => {
-                const msg = c.commit.message.toLowerCase();
-                const isMergeFromMain = mainBranches.some(branch =>
-                  msg.startsWith(`merge branch '${branch}'`) ||
-                  msg.includes(`merge remote-tracking branch '${branch}'`)
-                );
-                return !isMergeFromMain;
-              });
+              console.log(`Found ${prs.length} open PRs to check`);
 
-              const { data: checks } = await github.rest.checks.listForRef({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                ref: pr.head.sha
-              });
+              for (const pr of prs) {
+                try {
+                  const updated = new Date(pr.updated_at);
+                  
+                  if (updated > cutoff) {
+                    console.log(`⏩ Skipping PR #${pr.number} - updated recently`);
+                    continue;
+                  }
+
+                  console.log(`🔍 Checking PR #${pr.number}: "${pr.title}"`);
+
+                  // Get commits
+                  const commits = await github.paginate(github.rest.pulls.listCommits, {
+                    owner: context.repo.owner,
+                    repo: context.repo.repo,
+                    pull_number: pr.number,
+                    per_page: 100
+                  });
+
+                  const meaningfulCommits = commits.filter(c => {
+                    const msg = c.commit.message.toLowerCase();
+                    const isMergeFromMain = mainBranches.some(branch =>
+                      msg.startsWith(`merge branch '${branch}'`) ||
+                      msg.includes(`merge remote-tracking branch '${branch}'`)
+                    );
+                    return !isMergeFromMain;
+                  });
+
+                  // Get checks with error handling
+                  let hasFailedChecks = false;
+                  let allChecksCompleted = false;
+                  let hasChecks = false;
+                  
+                  try {
+                    const { data: checks } = await github.rest.checks.listForRef({
+                      owner: context.repo.owner,
+                      repo: context.repo.repo,
+                      ref: pr.head.sha
+                    });
+                    
+                    hasChecks = checks.check_runs.length > 0;
+                    hasFailedChecks = checks.check_runs.some(c => c.conclusion === 'failure');
+                    allChecksCompleted = checks.check_runs.every(c => 
+                      c.status === 'completed' || c.status === 'skipped'
+                    );
+                  } catch (error) {
+                    console.log(`⚠️ Could not fetch checks for PR #${pr.number}: ${error.message}`);
+                  }
+
+                  // Get workflow runs with error handling
+                  let hasFailedWorkflows = false;
+                  let allWorkflowsCompleted = false;
+                  let hasWorkflows = false;
+                  
+                  try {
+                    const { data: runs } = await github.rest.actions.listWorkflowRuns({
+                      owner: context.repo.owner,
+                      repo: context.repo.repo,
+                      head_sha: pr.head.sha,
+                      per_page: 50
+                    });
+
+                    hasWorkflows = runs.workflow_runs.length > 0;
+                    hasFailedWorkflows = runs.workflow_runs.some(r => r.conclusion === 'failure');
+                    allWorkflowsCompleted = runs.workflow_runs.every(r => 
+                      ['completed', 'skipped', 'cancelled'].includes(r.status)
+                    );
+
+                    console.log(`PR #${pr.number}: ${runs.workflow_runs.length} workflow runs found`);
+
+                  } catch (error) {
+                    console.log(`⚠️ Could not fetch workflow runs for PR #${pr.number}: ${error.message}`);
+                  }
+
+                  console.log(`PR #${pr.number}: ${meaningfulCommits.length} meaningful commits`);
+                  console.log(`Checks - has: ${hasChecks}, failed: ${hasFailedChecks}, completed: ${allChecksCompleted}`);
+                  console.log(`Workflows - has: ${hasWorkflows}, failed: ${hasFailedWorkflows}, completed: ${allWorkflowsCompleted}`);
+
+                  // Combine conditions - only consider if we actually have checks/workflows
+                  const hasAnyFailure = (hasChecks && hasFailedChecks) || (hasWorkflows && hasFailedWorkflows);
+                  const allCompleted = (!hasChecks || allChecksCompleted) && (!hasWorkflows || allWorkflowsCompleted);
+
+                  if (meaningfulCommits.length === 0 && hasAnyFailure && allCompleted) {
+                    console.log(`✅ Closing PR #${pr.number} (${pr.title})`);
+
+                    await github.rest.issues.createComment({
+                      owner: context.repo.owner,
+                      repo: context.repo.repo,
+                      issue_number: pr.number,
+                      body: `This pull request has been automatically closed because its workflows or checks failed and it has been inactive for more than ${cutoffDays} days. Please fix the workflows and reopen if you'd like to continue. Merging from main/master alone does not count as activity.`
+                    });
+
+                    await github.rest.pulls.update({
+                      owner: context.repo.owner,
+                      repo: context.repo.repo,
+                      pull_number: pr.number,
+                      state: 'closed'
+                    });
+                    
+                    console.log(`✅ Successfully closed PR #${pr.number}`);
+                  } else {
+                    console.log(`⏩ Not closing PR #${pr.number} - conditions not met`);
+                  }
 
-              const hasFailed = checks.check_runs.some(c => c.conclusion === 'failure');
-              const allCompleted = checks.check_runs.every(c => c.status === 'completed');
-
-              if (meaningfulCommits.length === 0 && hasFailed && allCompleted) {
-                console.log(`Closing PR #${pr.number} (${pr.title})`);
-
-                await github.rest.issues.createComment({
-                  owner: context.repo.owner,
-                  repo: context.repo.repo,
-                  issue_number: pr.number,
-                  body: `This pull request has been automatically closed because its workflows failed and it has been inactive for more than ${cutoffDays} days. Please fix the workflows and reopen if you'd like to continue. Merging from main/master alone does not count as activity.`
-                });
-
-                await github.rest.pulls.update({
-                  owner: context.repo.owner,
-                  repo: context.repo.repo,
-                  pull_number: pr.number,
-                  state: 'closed'
-                });
+                } catch (prError) {
+                  console.error(`❌ Error processing PR #${pr.number}: ${prError.message}`);
+                  continue;
+                }
               }
+              
+            } catch (error) {
+              console.error(`❌ Fatal error: ${error.message}`);
+              throw error;
             }
\ No newline at end of file

From 21eff8ad094c8cf4cf5b79bea8f4f872319cb2e7 Mon Sep 17 00:00:00 2001
From: Taranjeet Singh Kalsi <taranjeetkalsi15@gmail.com>
Date: Mon, 27 Oct 2025 02:09:39 +0530
Subject: [PATCH 1051/1338] Added binary string to decimal converter (#6915)

added binary string to decimal converter
---
 .../conversions/BinaryToDecimal.java          | 26 +++++++++++++++++++
 .../conversions/BinaryToDecimalTest.java      | 14 ++++++++++
 2 files changed, 40 insertions(+)

diff --git a/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java b/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
index 36c0790e565f..b3783ab284b2 100644
--- a/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
+++ b/src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java
@@ -30,4 +30,30 @@ public static long binaryToDecimal(long binaryNumber) {
         }
         return decimalValue;
     }
+
+    /**
+     * Converts a binary String to its decimal equivalent using bitwise operators.
+     *
+     * @param binary The binary number to convert.
+     * @return The decimal equivalent of the binary number.
+     * @throws IllegalArgumentException If the binary number contains digits other than 0 and 1.
+     */
+    public static long binaryStringToDecimal(String binary) {
+        boolean isNegative = binary.charAt(0) == '-';
+        if (isNegative) {
+            binary = binary.substring(1);
+        }
+
+        long decimalValue = 0;
+
+        for (char bit : binary.toCharArray()) {
+            if (bit != '0' && bit != '1') {
+                throw new IllegalArgumentException("Incorrect binary digit: " + bit);
+            }
+            // shift left by 1 (multiply by 2) and add bit value
+            decimalValue = (decimalValue << 1) | (bit - '0');
+        }
+
+        return isNegative ? -decimalValue : decimalValue;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java b/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java
index 9045d100285e..e11a86b4c006 100644
--- a/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java
+++ b/src/test/java/com/thealgorithms/conversions/BinaryToDecimalTest.java
@@ -18,6 +18,12 @@ public void testBinaryToDecimal() {
         assertEquals(5, BinaryToDecimal.binaryToDecimal(101));
         assertEquals(63, BinaryToDecimal.binaryToDecimal(111111));
         assertEquals(512, BinaryToDecimal.binaryToDecimal(1000000000));
+
+        assertEquals(0, BinaryToDecimal.binaryStringToDecimal("0"));
+        assertEquals(1, BinaryToDecimal.binaryStringToDecimal("1"));
+        assertEquals(5, BinaryToDecimal.binaryStringToDecimal("101"));
+        assertEquals(63, BinaryToDecimal.binaryStringToDecimal("111111"));
+        assertEquals(512, BinaryToDecimal.binaryStringToDecimal("1000000000"));
     }
 
     @Test
@@ -25,6 +31,9 @@ public void testBinaryToDecimal() {
     public void testNegativeBinaryToDecimal() {
         assertEquals(-1, BinaryToDecimal.binaryToDecimal(-1));
         assertEquals(-42, BinaryToDecimal.binaryToDecimal(-101010));
+
+        assertEquals(-1, BinaryToDecimal.binaryStringToDecimal("-1"));
+        assertEquals(-42, BinaryToDecimal.binaryStringToDecimal("-101010"));
     }
 
     @Test
@@ -32,11 +41,16 @@ public void testNegativeBinaryToDecimal() {
     public void testLargeBinaryToDecimal() {
         assertEquals(262144L, BinaryToDecimal.binaryToDecimal(1000000000000000000L));
         assertEquals(524287L, BinaryToDecimal.binaryToDecimal(1111111111111111111L));
+
+        assertEquals(262144L, BinaryToDecimal.binaryStringToDecimal("1000000000000000000"));
+        assertEquals(524287L, BinaryToDecimal.binaryStringToDecimal("1111111111111111111"));
     }
 
     @ParameterizedTest
     @CsvSource({"2", "1234", "11112", "101021"})
     void testNotCorrectBinaryInput(long binaryNumber) {
         assertThrows(IllegalArgumentException.class, () -> BinaryToDecimal.binaryToDecimal(binaryNumber));
+
+        assertThrows(IllegalArgumentException.class, () -> BinaryToDecimal.binaryStringToDecimal(Long.toString(binaryNumber)));
     }
 }

From 55da3b9ee10e7438b5c922b73c6fd7da008d3832 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 27 Oct 2025 23:31:49 +0100
Subject: [PATCH 1052/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 12.1.0 to 12.1.1 (#6972)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 12.1.0 to 12.1.1.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-12.1.0...checkstyle-12.1.1)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 12.1.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 116c7bb27e40..b7ca85e1407c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>12.1.0</version>
+                    <version>12.1.1</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 14a0de41817d11b4ecfda549b32b8e78dedb1991 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 28 Oct 2025 09:12:35 +0000
Subject: [PATCH 1053/1338] chore(deps): bump actions/github-script from 7 to 8
 in /.github/workflows (#6971)

chore(deps): bump actions/github-script in /.github/workflows

Bumps [actions/github-script](https://github.com/actions/github-script) from 7 to 8.
- [Release notes](https://github.com/actions/github-script/releases)
- [Commits](https://github.com/actions/github-script/compare/v7...v8)

---
updated-dependencies:
- dependency-name: actions/github-script
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/close-failed-prs.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/close-failed-prs.yml b/.github/workflows/close-failed-prs.yml
index 5d54eea07821..f1bf3690f13f 100644
--- a/.github/workflows/close-failed-prs.yml
+++ b/.github/workflows/close-failed-prs.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Close stale PRs
-        uses: actions/github-script@v7
+        uses: actions/github-script@v8
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |

From 3c70a543559ad043b5f72789c122e9a85f143195 Mon Sep 17 00:00:00 2001
From: Keykyrios <mitrajitghorui@gmail.com>
Date: Tue, 28 Oct 2025 15:44:59 +0530
Subject: [PATCH 1054/1338] feat: Add Neville's Algorithm (#6842)

* feat: Add Neville's algorithm for polynomial interpolation

* Update Neville.java

* style: Fix linter formatting issues.

* Handled Div by Zero Case

* Update NevilleTest.java

* Update Neville.java

* Update NevilleTest.java

* Update Neville.java
---
 .../java/com/thealgorithms/maths/Neville.java | 61 ++++++++++++++++
 .../com/thealgorithms/maths/NevilleTest.java  | 69 +++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/Neville.java
 create mode 100644 src/test/java/com/thealgorithms/maths/NevilleTest.java

diff --git a/src/main/java/com/thealgorithms/maths/Neville.java b/src/main/java/com/thealgorithms/maths/Neville.java
new file mode 100644
index 000000000000..ca45f2e8a042
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/Neville.java
@@ -0,0 +1,61 @@
+package com.thealgorithms.maths;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * In numerical analysis, Neville's algorithm is an algorithm used for
+ * polynomial interpolation. Given n+1 points, there is a unique polynomial of
+ * degree at most n that passes through all the points. Neville's algorithm
+ * computes the value of this polynomial at a given point.
+ *
+ * <p>
+ * Wikipedia: https://en.wikipedia.org/wiki/Neville%27s_algorithm
+ *
+ * @author Mitrajit Ghorui(KeyKyrios)
+ */
+public final class Neville {
+
+    private Neville() {
+    }
+
+    /**
+     * Evaluates the polynomial that passes through the given points at a
+     * specific x-coordinate.
+     *
+     * @param x The x-coordinates of the points. Must be the same length as y.
+     * @param y The y-coordinates of the points. Must be the same length as x.
+     * @param target The x-coordinate at which to evaluate the polynomial.
+     * @return The interpolated y-value at the target x-coordinate.
+     * @throws IllegalArgumentException if the lengths of x and y arrays are
+     * different, if the arrays are empty, or if x-coordinates are not unique.
+     */
+    public static double interpolate(double[] x, double[] y, double target) {
+        if (x.length != y.length) {
+            throw new IllegalArgumentException("x and y arrays must have the same length.");
+        }
+        if (x.length == 0) {
+            throw new IllegalArgumentException("Input arrays cannot be empty.");
+        }
+
+        // Check for duplicate x-coordinates to prevent division by zero
+        Set<Double> seenX = new HashSet<>();
+        for (double val : x) {
+            if (!seenX.add(val)) {
+                throw new IllegalArgumentException("Input x-coordinates must be unique.");
+            }
+        }
+
+        int n = x.length;
+        double[] p = new double[n];
+        System.arraycopy(y, 0, p, 0, n); // Initialize p with y values
+
+        for (int k = 1; k < n; k++) {
+            for (int i = 0; i < n - k; i++) {
+                p[i] = ((target - x[i + k]) * p[i] + (x[i] - target) * p[i + 1]) / (x[i] - x[i + k]);
+            }
+        }
+
+        return p[0];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/NevilleTest.java b/src/test/java/com/thealgorithms/maths/NevilleTest.java
new file mode 100644
index 000000000000..234fb2d65ce4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/NevilleTest.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class NevilleTest {
+
+    @Test
+    public void testInterpolateLinear() {
+        // Test with a simple linear function y = 2x + 1
+        // Points (0, 1) and (2, 5)
+        double[] x = {0, 2};
+        double[] y = {1, 5};
+        // We want to find y when x = 1, which should be 3
+        double target = 1;
+        double expected = 3.0;
+        assertEquals(expected, Neville.interpolate(x, y, target), 1e-9);
+    }
+
+    @Test
+    public void testInterpolateQuadratic() {
+        // Test with a quadratic function y = x^2
+        // Points (0, 0), (1, 1), (3, 9)
+        double[] x = {0, 1, 3};
+        double[] y = {0, 1, 9};
+        // We want to find y when x = 2, which should be 4
+        double target = 2;
+        double expected = 4.0;
+        assertEquals(expected, Neville.interpolate(x, y, target), 1e-9);
+    }
+
+    @Test
+    public void testInterpolateWithNegativeNumbers() {
+        // Test with y = x^2 - 2x + 1
+        // Points (-1, 4), (0, 1), (2, 1)
+        double[] x = {-1, 0, 2};
+        double[] y = {4, 1, 1};
+        // We want to find y when x = 1, which should be 0
+        double target = 1;
+        double expected = 0.0;
+        assertEquals(expected, Neville.interpolate(x, y, target), 1e-9);
+    }
+
+    @Test
+    public void testMismatchedArrayLengths() {
+        double[] x = {1, 2};
+        double[] y = {1};
+        double target = 1.5;
+        assertThrows(IllegalArgumentException.class, () -> Neville.interpolate(x, y, target));
+    }
+
+    @Test
+    public void testEmptyArrays() {
+        double[] x = {};
+        double[] y = {};
+        double target = 1;
+        assertThrows(IllegalArgumentException.class, () -> Neville.interpolate(x, y, target));
+    }
+
+    @Test
+    public void testDuplicateXCoordinates() {
+        double[] x = {1, 2, 1};
+        double[] y = {5, 8, 3};
+        double target = 1.5;
+        assertThrows(IllegalArgumentException.class, () -> Neville.interpolate(x, y, target));
+    }
+}

From 68746f880f717dfe0ecb5f655da3338bbe179529 Mon Sep 17 00:00:00 2001
From: Keykyrios <mitrajitghorui@gmail.com>
Date: Tue, 28 Oct 2025 21:13:54 +0530
Subject: [PATCH 1055/1338] feat: Add Chebyshev Iteration algorithm (#6963)

* feat: Add Chebyshev Iteration algorithm

* Update ChebyshevIteration.java

* Update ChebyshevIterationTest.java

* Update ChebyshevIteration.java

* Update ChebyshevIterationTest.java

* Update ChebyshevIteration.java

* Update ChebyshevIteration.java

* Update ChebyshevIterationTest.java

* Update ChebyshevIteration.java

* Update ChebyshevIterationTest.java

* Update ChebyshevIterationTest.java

* Update ChebyshevIteration.java

* Update ChebyshevIteration.java

* Update ChebyshevIterationTest.java

* Update ChebyshevIteration.java

* Update ChebyshevIterationTest.java

* Update ChebyshevIteration.java

* Update ChebyshevIterationTest.java

* update

* Update ChebyshevIteration.java

* Update ChebyshevIterationTest.java

* Update ChebyshevIteration.java

* Update ChebyshevIterationTest.java

* Update ChebyshevIteration.java

* Update ChebyshevIterationTest.java
---
 .../maths/ChebyshevIteration.java             | 181 ++++++++++++++++++
 .../maths/ChebyshevIterationTest.java         | 105 ++++++++++
 2 files changed, 286 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/ChebyshevIteration.java
 create mode 100644 src/test/java/com/thealgorithms/maths/ChebyshevIterationTest.java

diff --git a/src/main/java/com/thealgorithms/maths/ChebyshevIteration.java b/src/main/java/com/thealgorithms/maths/ChebyshevIteration.java
new file mode 100644
index 000000000000..bc30f1ba6e7e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/ChebyshevIteration.java
@@ -0,0 +1,181 @@
+package com.thealgorithms.maths;
+
+/**
+ * In numerical analysis, Chebyshev iteration is an iterative method for solving
+ * systems of linear equations Ax = b. It is designed for systems where the
+ * matrix A is symmetric positive-definite (SPD).
+ *
+ * <p>
+ * This method is a "polynomial acceleration" method, meaning it finds the
+ * optimal polynomial to apply to the residual to accelerate convergence.
+ *
+ * <p>
+ * It requires knowledge of the bounds of the eigenvalues of the matrix A:
+ * m(A) (smallest eigenvalue) and M(A) (largest eigenvalue).
+ *
+ * <p>
+ * Wikipedia: https://en.wikipedia.org/wiki/Chebyshev_iteration
+ *
+ * @author Mitrajit Ghorui(KeyKyrios)
+ */
+public final class ChebyshevIteration {
+
+    private ChebyshevIteration() {
+    }
+
+    /**
+     * Solves the linear system Ax = b using the Chebyshev iteration method.
+     *
+     * <p>
+     * NOTE: The matrix A *must* be symmetric positive-definite (SPD) for this
+     * algorithm to converge.
+     *
+     * @param a The matrix A (must be square, SPD).
+     * @param b The vector b.
+     * @param x0 The initial guess vector.
+     * @param minEigenvalue The smallest eigenvalue of A (m(A)).
+     * @param maxEigenvalue The largest eigenvalue of A (M(A)).
+     * @param maxIterations The maximum number of iterations to perform.
+     * @param tolerance The desired tolerance for the residual norm.
+     * @return The solution vector x.
+     * @throws IllegalArgumentException if matrix/vector dimensions are
+     * incompatible,
+     * if maxIterations <= 0, or if eigenvalues are invalid (e.g., minEigenvalue
+     * <= 0, maxEigenvalue <= minEigenvalue).
+     */
+    public static double[] solve(double[][] a, double[] b, double[] x0, double minEigenvalue, double maxEigenvalue, int maxIterations, double tolerance) {
+        validateInputs(a, b, x0, minEigenvalue, maxEigenvalue, maxIterations, tolerance);
+
+        int n = b.length;
+        double[] x = x0.clone();
+        double[] r = vectorSubtract(b, matrixVectorMultiply(a, x));
+        double[] p = new double[n];
+
+        double d = (maxEigenvalue + minEigenvalue) / 2.0;
+        double c = (maxEigenvalue - minEigenvalue) / 2.0;
+
+        double alpha = 0.0;
+        double alphaPrev = 0.0;
+
+        for (int k = 0; k < maxIterations; k++) {
+            double residualNorm = vectorNorm(r);
+            if (residualNorm < tolerance) {
+                return x; // Solution converged
+            }
+
+            if (k == 0) {
+                alpha = 1.0 / d;
+                System.arraycopy(r, 0, p, 0, n); // p = r
+            } else {
+                double beta = c * alphaPrev / 2.0 * (c * alphaPrev / 2.0);
+                alpha = 1.0 / (d - beta / alphaPrev);
+                double[] pUpdate = scalarMultiply(beta / alphaPrev, p);
+                p = vectorAdd(r, pUpdate); // p = r + (beta / alphaPrev) * p
+            }
+
+            double[] xUpdate = scalarMultiply(alpha, p);
+            x = vectorAdd(x, xUpdate); // x = x + alpha * p
+
+            // Recompute residual for accuracy
+            r = vectorSubtract(b, matrixVectorMultiply(a, x));
+            alphaPrev = alpha;
+        }
+
+        return x; // Return best guess after maxIterations
+    }
+
+    /**
+     * Validates the inputs for the Chebyshev solver.
+     */
+    private static void validateInputs(double[][] a, double[] b, double[] x0, double minEigenvalue, double maxEigenvalue, int maxIterations, double tolerance) {
+        int n = a.length;
+        if (n == 0) {
+            throw new IllegalArgumentException("Matrix A cannot be empty.");
+        }
+        if (n != a[0].length) {
+            throw new IllegalArgumentException("Matrix A must be square.");
+        }
+        if (n != b.length) {
+            throw new IllegalArgumentException("Matrix A and vector b dimensions do not match.");
+        }
+        if (n != x0.length) {
+            throw new IllegalArgumentException("Matrix A and vector x0 dimensions do not match.");
+        }
+        if (minEigenvalue <= 0) {
+            throw new IllegalArgumentException("Smallest eigenvalue must be positive (matrix must be positive-definite).");
+        }
+        if (maxEigenvalue <= minEigenvalue) {
+            throw new IllegalArgumentException("Max eigenvalue must be strictly greater than min eigenvalue.");
+        }
+        if (maxIterations <= 0) {
+            throw new IllegalArgumentException("Max iterations must be positive.");
+        }
+        if (tolerance <= 0) {
+            throw new IllegalArgumentException("Tolerance must be positive.");
+        }
+    }
+
+    // --- Vector/Matrix Helper Methods ---
+    /**
+     * Computes the product of a matrix A and a vector v (Av).
+     */
+    private static double[] matrixVectorMultiply(double[][] a, double[] v) {
+        int n = a.length;
+        double[] result = new double[n];
+        for (int i = 0; i < n; i++) {
+            double sum = 0;
+            for (int j = 0; j < n; j++) {
+                sum += a[i][j] * v[j];
+            }
+            result[i] = sum;
+        }
+        return result;
+    }
+
+    /**
+     * Computes the subtraction of two vectors (v1 - v2).
+     */
+    private static double[] vectorSubtract(double[] v1, double[] v2) {
+        int n = v1.length;
+        double[] result = new double[n];
+        for (int i = 0; i < n; i++) {
+            result[i] = v1[i] - v2[i];
+        }
+        return result;
+    }
+
+    /**
+     * Computes the addition of two vectors (v1 + v2).
+     */
+    private static double[] vectorAdd(double[] v1, double[] v2) {
+        int n = v1.length;
+        double[] result = new double[n];
+        for (int i = 0; i < n; i++) {
+            result[i] = v1[i] + v2[i];
+        }
+        return result;
+    }
+
+    /**
+     * Computes the product of a scalar and a vector (s * v).
+     */
+    private static double[] scalarMultiply(double scalar, double[] v) {
+        int n = v.length;
+        double[] result = new double[n];
+        for (int i = 0; i < n; i++) {
+            result[i] = scalar * v[i];
+        }
+        return result;
+    }
+
+    /**
+     * Computes the L2 norm (Euclidean norm) of a vector.
+     */
+    private static double vectorNorm(double[] v) {
+        double sumOfSquares = 0;
+        for (double val : v) {
+            sumOfSquares += val * val;
+        }
+        return Math.sqrt(sumOfSquares);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/ChebyshevIterationTest.java b/src/test/java/com/thealgorithms/maths/ChebyshevIterationTest.java
new file mode 100644
index 000000000000..d5cf83818fa4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/ChebyshevIterationTest.java
@@ -0,0 +1,105 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class ChebyshevIterationTest {
+
+    @Test
+    public void testSolveSimple2x2Diagonal() {
+        double[][] a = {{2, 0}, {0, 1}};
+        double[] b = {2, 2};
+        double[] x0 = {0, 0};
+        double minEig = 1.0;
+        double maxEig = 2.0;
+        int maxIter = 50;
+        double tol = 1e-9;
+        double[] expected = {1.0, 2.0};
+
+        double[] result = ChebyshevIteration.solve(a, b, x0, minEig, maxEig, maxIter, tol);
+        assertArrayEquals(expected, result, 1e-9);
+    }
+
+    @Test
+    public void testSolve2x2Symmetric() {
+        double[][] a = {{4, 1}, {1, 3}};
+        double[] b = {1, 2};
+        double[] x0 = {0, 0};
+        double minEig = (7.0 - Math.sqrt(5.0)) / 2.0;
+        double maxEig = (7.0 + Math.sqrt(5.0)) / 2.0;
+        int maxIter = 100;
+        double tol = 1e-10;
+        double[] expected = {1.0 / 11.0, 7.0 / 11.0};
+
+        double[] result = ChebyshevIteration.solve(a, b, x0, minEig, maxEig, maxIter, tol);
+        assertArrayEquals(expected, result, 1e-9);
+    }
+
+    @Test
+    public void testAlreadyAtSolution() {
+        double[][] a = {{2, 0}, {0, 1}};
+        double[] b = {2, 2};
+        double[] x0 = {1, 2};
+        double minEig = 1.0;
+        double maxEig = 2.0;
+        int maxIter = 10;
+        double tol = 1e-5;
+        double[] expected = {1.0, 2.0};
+
+        double[] result = ChebyshevIteration.solve(a, b, x0, minEig, maxEig, maxIter, tol);
+        assertArrayEquals(expected, result, 0.0);
+    }
+
+    @Test
+    public void testMismatchedDimensionsAB() {
+        double[][] a = {{1, 0}, {0, 1}};
+        double[] b = {1};
+        double[] x0 = {0, 0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 2, 10, 1e-5));
+    }
+
+    @Test
+    public void testMismatchedDimensionsAX() {
+        double[][] a = {{1, 0}, {0, 1}};
+        double[] b = {1, 1};
+        double[] x0 = {0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 2, 10, 1e-5));
+    }
+
+    @Test
+    public void testNonSquareMatrix() {
+        double[][] a = {{1, 0, 0}, {0, 1, 0}};
+        double[] b = {1, 1};
+        double[] x0 = {0, 0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 2, 10, 1e-5));
+    }
+
+    @Test
+    public void testInvalidEigenvalues() {
+        double[][] a = {{1, 0}, {0, 1}};
+        double[] b = {1, 1};
+        double[] x0 = {0, 0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 2, 1, 10, 1e-5));
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 1, 10, 1e-5));
+    }
+
+    @Test
+    public void testNonPositiveDefinite() {
+        double[][] a = {{1, 0}, {0, 1}};
+        double[] b = {1, 1};
+        double[] x0 = {0, 0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 0, 1, 10, 1e-5));
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, -1, 1, 10, 1e-5));
+    }
+
+    @Test
+    public void testInvalidIterationCount() {
+        double[][] a = {{1, 0}, {0, 1}};
+        double[] b = {1, 1};
+        double[] x0 = {0, 0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 2, 0, 1e-5));
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 2, -1, 1e-5));
+    }
+}

From bb6385e756a0159a29655c745682e95ca7b41ada Mon Sep 17 00:00:00 2001
From: sairamsharan <143504336+sairamsharan@users.noreply.github.com>
Date: Wed, 29 Oct 2025 14:38:05 +0530
Subject: [PATCH 1056/1338] feat: Add Stoer-Wagner Algorithm for Minimum Cut
 (#6752)

* feat: Add Stoer-Wagner Algorithm for Minimum Cut

* fix: Correct Stoer-Wagner implementation

* fix: Remove unused import

* fix: Apply clang-format
---
 .../com/thealgorithms/graph/StoerWagner.java  | 78 +++++++++++++++++++
 .../thealgorithms/graph/StoerWagnerTest.java  | 64 +++++++++++++++
 2 files changed, 142 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/StoerWagner.java
 create mode 100644 src/test/java/com/thealgorithms/graph/StoerWagnerTest.java

diff --git a/src/main/java/com/thealgorithms/graph/StoerWagner.java b/src/main/java/com/thealgorithms/graph/StoerWagner.java
new file mode 100644
index 000000000000..b204834c431a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/StoerWagner.java
@@ -0,0 +1,78 @@
+package com.thealgorithms.graph;
+
+/**
+ * An implementation of the Stoer-Wagner algorithm to find the global minimum cut of an undirected, weighted graph.
+ * A minimum cut is a partition of the graph's vertices into two disjoint sets with the minimum possible edge weight
+ * sum connecting the two sets.
+ *
+ * Wikipedia: https://en.wikipedia.org/wiki/Stoer%E2%80%93Wagner_algorithm
+ * Time Complexity: O(V^3) where V is the number of vertices.
+ */
+public class StoerWagner {
+
+    /**
+     * Finds the minimum cut in the given undirected, weighted graph.
+     *
+     * @param graph An adjacency matrix representing the graph. graph[i][j] is the weight of the edge between i and j.
+     * @return The weight of the minimum cut.
+     */
+    public int findMinCut(int[][] graph) {
+        int n = graph.length;
+        if (n < 2) {
+            return 0;
+        }
+
+        int[][] currentGraph = new int[n][n];
+        for (int i = 0; i < n; i++) {
+            System.arraycopy(graph[i], 0, currentGraph[i], 0, n);
+        }
+
+        int minCut = Integer.MAX_VALUE;
+        boolean[] merged = new boolean[n];
+
+        for (int phase = 0; phase < n - 1; phase++) {
+            boolean[] inSetA = new boolean[n];
+            int[] weights = new int[n];
+            int prev = -1;
+            int last = -1;
+
+            for (int i = 0; i < n - phase; i++) {
+                int maxWeight = -1;
+                int currentVertex = -1;
+
+                for (int j = 0; j < n; j++) {
+                    if (!merged[j] && !inSetA[j] && weights[j] > maxWeight) {
+                        maxWeight = weights[j];
+                        currentVertex = j;
+                    }
+                }
+
+                if (currentVertex == -1) {
+                    // This can happen if the graph is disconnected.
+                    return 0;
+                }
+
+                prev = last;
+                last = currentVertex;
+                inSetA[last] = true;
+
+                for (int j = 0; j < n; j++) {
+                    if (!merged[j] && !inSetA[j]) {
+                        weights[j] += currentGraph[last][j];
+                    }
+                }
+            }
+
+            minCut = Math.min(minCut, weights[last]);
+
+            // Merge 'last' vertex into 'prev' vertex
+            for (int i = 0; i < n; i++) {
+                currentGraph[prev][i] += currentGraph[last][i];
+                currentGraph[i][prev] = currentGraph[prev][i];
+            }
+            merged[last] = true;
+        }
+
+        return minCut;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/StoerWagnerTest.java b/src/test/java/com/thealgorithms/graph/StoerWagnerTest.java
new file mode 100644
index 000000000000..894d99687d1d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/StoerWagnerTest.java
@@ -0,0 +1,64 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the StoerWagner global minimum cut algorithm.
+ *
+ * These tests verify correctness of the implementation across
+ * several graph configurations: simple, complete, disconnected,
+ * and small edge cases.
+ */
+public class StoerWagnerTest {
+
+    @Test
+    public void testSimpleGraph() {
+        int[][] graph = {{0, 3, 2, 0}, {3, 0, 1, 4}, {2, 1, 0, 5}, {0, 4, 5, 0}};
+        StoerWagner algo = new StoerWagner();
+        assertEquals(5, algo.findMinCut(graph)); // Correct minimum cut = 5
+    }
+
+    @Test
+    public void testTriangleGraph() {
+        int[][] graph = {{0, 2, 3}, {2, 0, 4}, {3, 4, 0}};
+        StoerWagner algo = new StoerWagner();
+        assertEquals(5, algo.findMinCut(graph)); // min cut = 5
+    }
+
+    @Test
+    public void testDisconnectedGraph() {
+        int[][] graph = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};
+        StoerWagner algo = new StoerWagner();
+        assertEquals(0, algo.findMinCut(graph)); // Disconnected graph => cut = 0
+    }
+
+    @Test
+    public void testCompleteGraph() {
+        int[][] graph = {{0, 1, 1, 1}, {1, 0, 1, 1}, {1, 1, 0, 1}, {1, 1, 1, 0}};
+        StoerWagner algo = new StoerWagner();
+        assertEquals(3, algo.findMinCut(graph)); // Each vertex connected to all others
+    }
+
+    @Test
+    public void testSingleVertex() {
+        int[][] graph = {{0}};
+        StoerWagner algo = new StoerWagner();
+        assertEquals(0, algo.findMinCut(graph)); // Only one vertex
+    }
+
+    @Test
+    public void testTwoVertices() {
+        int[][] graph = {{0, 7}, {7, 0}};
+        StoerWagner algo = new StoerWagner();
+        assertEquals(7, algo.findMinCut(graph)); // Only one edge, cut weight = 7
+    }
+
+    @Test
+    public void testSquareGraphWithDiagonal() {
+        int[][] graph = {{0, 2, 0, 2}, {2, 0, 3, 0}, {0, 3, 0, 4}, {2, 0, 4, 0}};
+        StoerWagner algo = new StoerWagner();
+        assertEquals(4, algo.findMinCut(graph)); // verified manually
+    }
+}

From dfd8d6993fe85b9913eb314c031c85fddb816ae5 Mon Sep 17 00:00:00 2001
From: JonathanButterworth
 <149101933+JonathanButterworth@users.noreply.github.com>
Date: Thu, 30 Oct 2025 17:26:22 -0400
Subject: [PATCH 1057/1338] Added surface area calculation for pyramid (#6853)

Co-authored-by: JonathanButterworth <JonathanButterworth>
---
 .../java/com/thealgorithms/maths/Area.java    | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/main/java/com/thealgorithms/maths/Area.java b/src/main/java/com/thealgorithms/maths/Area.java
index 7a06fd5e5fa0..a34ad6b01ab5 100644
--- a/src/main/java/com/thealgorithms/maths/Area.java
+++ b/src/main/java/com/thealgorithms/maths/Area.java
@@ -48,6 +48,25 @@ public static double surfaceAreaSphere(final double radius) {
         return 4 * Math.PI * radius * radius;
     }
 
+    /**
+     * Calculate the surface area of a pyramid with a square base.
+     *
+     * @param sideLength side length of the square base
+     * @param slantHeight slant height of the pyramid
+     * @return surface area of the given pyramid
+     */
+    public static double surfaceAreaPyramid(final double sideLength, final double slantHeight) {
+        if (sideLength <= 0) {
+            throw new IllegalArgumentException("Must be a positive sideLength");
+        }
+        if (slantHeight <= 0) {
+            throw new IllegalArgumentException("Must be a positive slantHeight");
+        }
+        double baseArea = sideLength * sideLength;
+        double lateralSurfaceArea = 2 * sideLength * slantHeight;
+        return baseArea + lateralSurfaceArea;
+    }
+
     /**
      * Calculate the area of a rectangle.
      *

From bf8cc61254b7909ef184c0b6da32f7f862afab7a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 1 Nov 2025 10:23:35 +0100
Subject: [PATCH 1058/1338] chore(deps): bump org.junit:junit-bom from 6.0.0 to
 6.0.1 (#7019)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 6.0.0 to 6.0.1.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r6.0.0...r6.0.1)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 6.0.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b7ca85e1407c..825d86f8b239 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>6.0.0</version>
+                <version>6.0.1</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 08374248e9cee8780cb6dee9524bcaaef708aa9b Mon Sep 17 00:00:00 2001
From: Priyanshu Kumar Singh <priyanshu1303d@gmail.com>
Date: Sat, 1 Nov 2025 14:58:44 +0530
Subject: [PATCH 1059/1338] [FEAT] Add Coulomb's Law for electrostatics (#7017)

Co-authored-by: Priyanshu1303d <priyanshu130d@gmail.com>
---
 .../thealgorithms/maths/JugglerSequence.java  |   2 +-
 .../thealgorithms/physics/CoulombsLaw.java    |  80 ++++++++++++++
 .../physics/CoulombsLawTest.java              | 100 ++++++++++++++++++
 3 files changed, 181 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/com/thealgorithms/physics/CoulombsLaw.java
 create mode 100644 src/test/java/com/thealgorithms/physics/CoulombsLawTest.java

diff --git a/src/main/java/com/thealgorithms/maths/JugglerSequence.java b/src/main/java/com/thealgorithms/maths/JugglerSequence.java
index 702310a1f295..a459b4b6d4bb 100644
--- a/src/main/java/com/thealgorithms/maths/JugglerSequence.java
+++ b/src/main/java/com/thealgorithms/maths/JugglerSequence.java
@@ -43,7 +43,7 @@ public static void jugglerSequence(int inputNumber) {
             seq.add(n + "");
         }
         String res = String.join(",", seq);
-        System.out.println(res);
+        System.out.print(res + "\n");
     }
 
     // Driver code
diff --git a/src/main/java/com/thealgorithms/physics/CoulombsLaw.java b/src/main/java/com/thealgorithms/physics/CoulombsLaw.java
new file mode 100644
index 000000000000..3a3ad3e0d223
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/CoulombsLaw.java
@@ -0,0 +1,80 @@
+package com.thealgorithms.physics;
+
+/**
+ * Implements Coulomb's Law for electrostatics.
+ * Provides simple static methods to calculate electrostatic force and circular orbit velocity.
+ *
+ * @author [Priyanshu Singh](https://github.com/Priyanshu1303d)
+ * @see <a href="https://en.wikipedia.org/wiki/Coulomb%27s_law">Wikipedia</a>
+ */
+public final class CoulombsLaw {
+
+    /** Coulomb's constant in N·m²/C² */
+    public static final double COULOMBS_CONSTANT = 8.9875517923e9;
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private CoulombsLaw() {
+    }
+
+    /**
+     * Calculates the electrostatic force vector exerted by one charge on another.
+     * The returned vector is the force *on* the second charge (q2).
+     *
+     * @param q1 Charge of the first particle (in Coulombs).
+     * @param x1 X-position of the first particle (m).
+     * @param y1 Y-position of the first particle (m).
+     * @param q2 Charge of the second particle (in Coulombs).
+     * @param x2 X-position of the second particle (m).
+     * @param y2 Y-position of the second particle (m).
+     * @return A double array `[fx, fy]` representing the force vector on the second charge.
+     */
+    public static double[] calculateForceVector(double q1, double x1, double y1, double q2, double x2, double y2) {
+        // Vector from 1 to 2
+        double dx = x2 - x1;
+        double dy = y2 - y1;
+        double distanceSq = dx * dx + dy * dy;
+
+        // If particles are at the same position, force is zero to avoid division by zero.
+        if (distanceSq == 0) {
+            return new double[] {0, 0};
+        }
+
+        double distance = Math.sqrt(distanceSq);
+        // Force magnitude: k * (q1 * q2) / r^2
+        // A positive result is repulsive (pushes q2 away from q1).
+        // A negative result is attractive (pulls q2 toward q1).
+        double forceMagnitude = COULOMBS_CONSTANT * q1 * q2 / distanceSq;
+
+        // Calculate the components of the force vector
+        // (dx / distance) is the unit vector pointing from 1 to 2.
+        double fx = forceMagnitude * (dx / distance);
+        double fy = forceMagnitude * (dy / distance);
+
+        return new double[] {fx, fy};
+    }
+
+    /**
+     * Calculates the speed required for a stable circular orbit of a charged particle
+     * around a central charge (e.g., an electron orbiting a nucleus).
+     *
+     * @param centralCharge The charge of the central body (in Coulombs).
+     * @param orbitingCharge The charge of the orbiting body (in Coulombs).
+     * @param orbitingMass The mass of the orbiting body (in kg).
+     * @param radius The radius of the orbit (in m).
+     * @return The orbital speed (in m/s).
+     * @throws IllegalArgumentException if mass or radius are not positive.
+     */
+    public static double calculateCircularOrbitVelocity(double centralCharge, double orbitingCharge, double orbitingMass, double radius) {
+        if (orbitingMass <= 0 || radius <= 0) {
+            throw new IllegalArgumentException("Orbiting mass and radius must be positive.");
+        }
+
+        // We only need the magnitude of the force, which is always positive.
+        double forceMagnitude = Math.abs(COULOMBS_CONSTANT * centralCharge * orbitingCharge) / (radius * radius);
+
+        // F_c = m * v^2 / r  =>  v = sqrt(F_c * r / m)
+        return Math.sqrt(forceMagnitude * radius / orbitingMass);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/CoulombsLawTest.java b/src/test/java/com/thealgorithms/physics/CoulombsLawTest.java
new file mode 100644
index 000000000000..9829e703bd10
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/CoulombsLawTest.java
@@ -0,0 +1,100 @@
+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the CoulombsLaw utility class.
+ */
+final class CoulombsLawTest {
+
+    // A small tolerance (delta) for comparing floating-point numbers
+    private static final double DELTA = 1e-9;
+    private static final double K = CoulombsLaw.COULOMBS_CONSTANT;
+
+    @Test
+    @DisplayName("Test repulsive force between two charges on the x-axis")
+    void testSimpleRepulsiveForce() {
+        // Two positive 1C charges, 1 meter apart.
+        // Force on q2 should be F = K*1*1 / 1^2 = K, directed away from q1 (positive x)
+        double[] forceOnB = CoulombsLaw.calculateForceVector(1.0, 0, 0, 1.0, 1, 0);
+        assertArrayEquals(new double[] {K, 0.0}, forceOnB, DELTA);
+
+        // Force on q1 should be equal and opposite (negative x)
+        double[] forceOnA = CoulombsLaw.calculateForceVector(1.0, 1, 0, 1.0, 0, 0);
+        assertArrayEquals(new double[] {-K, 0.0}, forceOnA, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test attractive force between two charges on the x-axis")
+    void testSimpleAttractiveForce() {
+        // One positive 1C, one negative -1C, 1 meter apart.
+        // Force on q2 should be F = K*1*(-1) / 1^2 = -K, directed toward q1 (negative x)
+        double[] forceOnB = CoulombsLaw.calculateForceVector(1.0, 0, 0, -1.0, 1, 0);
+        assertArrayEquals(new double[] {-K, 0.0}, forceOnB, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test electrostatic force in a 2D plane (repulsive)")
+    void test2DRepulsiveForce() {
+        // q1 at (0,0) with charge +2C
+        // q2 at (3,4) with charge +1C
+        // Distance is 5 meters.
+        double magnitude = K * 2.0 * 1.0 / 25.0; // 2K/25
+        // Unit vector from 1 to 2 is (3/5, 4/5)
+        double expectedFx = magnitude * (3.0 / 5.0); // 6K / 125
+        double expectedFy = magnitude * (4.0 / 5.0); // 8K / 125
+
+        double[] forceOnB = CoulombsLaw.calculateForceVector(2.0, 0, 0, 1.0, 3, 4);
+        assertArrayEquals(new double[] {expectedFx, expectedFy}, forceOnB, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test overlapping charges should result in zero force")
+    void testOverlappingCharges() {
+        double[] force = CoulombsLaw.calculateForceVector(1.0, 1.5, -2.5, -1.0, 1.5, -2.5);
+        assertArrayEquals(new double[] {0.0, 0.0}, force, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test circular orbit velocity with simple values")
+    void testCircularOrbitVelocity() {
+        // v = sqrt( (K*1*1 / 1^2) * 1 / 1 ) = sqrt(K)
+        double velocity = CoulombsLaw.calculateCircularOrbitVelocity(1.0, 1.0, 1.0, 1.0);
+        assertEquals(Math.sqrt(K), velocity, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test orbital velocity for a Hydrogen atom (Bohr model)")
+    void testHydrogenAtomVelocity() {
+        // Charge of a proton
+        double protonCharge = 1.602176634e-19;
+        // Charge of an electron
+        double electronCharge = -1.602176634e-19;
+        // Mass of an electron
+        double electronMass = 9.1093837e-31;
+        // Bohr radius (avg distance)
+        double bohrRadius = 5.29177e-11;
+
+        double expectedVelocity = 2.1876917e6;
+
+        double velocity = CoulombsLaw.calculateCircularOrbitVelocity(protonCharge, electronCharge, electronMass, bohrRadius);
+        // Use a wider delta for this real-world calculation
+        assertEquals(expectedVelocity, velocity, 1.0);
+    }
+
+    @Test
+    @DisplayName("Test invalid inputs for orbital velocity throw exception")
+    void testInvalidOrbitalVelocityInputs() {
+        // Non-positive mass
+        assertThrows(IllegalArgumentException.class, () -> CoulombsLaw.calculateCircularOrbitVelocity(1, 1, 0, 100));
+        assertThrows(IllegalArgumentException.class, () -> CoulombsLaw.calculateCircularOrbitVelocity(1, 1, -1, 100));
+        // Non-positive radius
+        assertThrows(IllegalArgumentException.class, () -> CoulombsLaw.calculateCircularOrbitVelocity(1, 1, 1, 0));
+        assertThrows(IllegalArgumentException.class, () -> CoulombsLaw.calculateCircularOrbitVelocity(1, 1, 1, -100));
+    }
+}

From d717ca4fd5d2bd151359964b5075cf785a080641 Mon Sep 17 00:00:00 2001
From: sharan <143504336+sairamsharan@users.noreply.github.com>
Date: Sun, 2 Nov 2025 16:06:10 +0530
Subject: [PATCH 1060/1338] feat: Add Hierholzer's Algorithm for Eulerian
 Circuits (#6726)

* feat: Add Hierholzer's Algorithm for Eulerian Circuits

* fix: Add more test cases to improve code coverage

* feat: Add Hierholzer's Algorithm for Eulerian Circuits

* fix: Apply clang-format after merge

* fix: Apply all formatting, style, and efficiency fixes

* docs: Apply feedback and improve Javadoc

* docs: Add Hierholzer's Algorithm to DIRECTORY.md
---
 DIRECTORY.md                                  |   1 +
 .../graph/HierholzerAlgorithm.java            | 140 ++++++++++++++++++
 .../graph/HierholzerAlgorithmTest.java        |  60 ++++++++
 3 files changed, 201 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/HierholzerAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/graph/HierholzerAlgorithmTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 47833a3f59f2..eca2453fad0f 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -173,6 +173,7 @@
             - 📄 [FordFulkerson](src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java)
             - 📄 [Graphs](src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java)
             - 📄 [HamiltonianCycle](src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java)
+            - 📄 [HierholzerAlgorithm](src/main/java/com/thealgorithms/graph/HierholzerAlgorithm.java)
             - 📄 [JohnsonsAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java)
             - 📄 [KahnsAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java)
             - 📄 [Kosaraju](src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java)
diff --git a/src/main/java/com/thealgorithms/graph/HierholzerAlgorithm.java b/src/main/java/com/thealgorithms/graph/HierholzerAlgorithm.java
new file mode 100644
index 000000000000..a804f77d7fa6
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/HierholzerAlgorithm.java
@@ -0,0 +1,140 @@
+package com.thealgorithms.graph;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.Stack;
+
+/**
+ * Implementation of Hierholzer's algorithm to find an Eulerian Circuit in an undirected graph.
+ * <p>
+ * An Eulerian circuit is a trail in a graph that visits every edge exactly once,
+ * starting and ending at the same vertex. This algorithm finds such a circuit if one exists.
+ * </p>
+ * <p>
+ * This implementation is designed for an <strong>undirected graph</strong>. For a valid Eulerian
+ * circuit to exist, the graph must satisfy two conditions:
+ * <ol>
+ * <li>All vertices with a non-zero degree must be part of a single connected component.</li>
+ * <li>Every vertex must have an even degree (an even number of edges connected to it).</li>
+ * </ol>
+ * </p>
+ * <p>
+ * The algorithm runs in O(E + V) time, where E is the number of edges and V is the number of vertices.
+ * The graph is represented by a Map where keys are vertices and values are a LinkedList of adjacent vertices.
+ * </p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Eulerian_path#Hierholzer's_algorithm">Wikipedia: Hierholzer's algorithm</a>
+ */
+public final class HierholzerAlgorithm {
+
+    private final Map<Integer, LinkedList<Integer>> graph;
+
+    public HierholzerAlgorithm(Map<Integer, LinkedList<Integer>> graph) {
+        this.graph = (graph == null) ? new HashMap<>() : graph;
+    }
+
+    public boolean hasEulerianCircuit() {
+        if (graph.isEmpty()) {
+            return true;
+        }
+
+        for (List<Integer> neighbors : graph.values()) {
+            if (neighbors.size() % 2 != 0) {
+                return false;
+            }
+        }
+
+        return isCoherentlyConnected();
+    }
+
+    public List<Integer> findEulerianCircuit() {
+        if (!hasEulerianCircuit()) {
+            return Collections.emptyList();
+        }
+
+        Map<Integer, LinkedList<Integer>> tempGraph = new HashMap<>();
+        for (Map.Entry<Integer, LinkedList<Integer>> entry : graph.entrySet()) {
+            tempGraph.put(entry.getKey(), new LinkedList<>(entry.getValue()));
+        }
+
+        Stack<Integer> currentPath = new Stack<>();
+        LinkedList<Integer> circuit = new LinkedList<>();
+
+        int startVertex = -1;
+        for (Map.Entry<Integer, LinkedList<Integer>> entry : tempGraph.entrySet()) {
+            if (!entry.getValue().isEmpty()) {
+                startVertex = entry.getKey();
+                break;
+            }
+        }
+
+        if (startVertex == -1) {
+            if (graph.isEmpty()) {
+                return Collections.emptyList();
+            }
+            return Collections.singletonList(graph.keySet().iterator().next());
+        }
+
+        currentPath.push(startVertex);
+
+        while (!currentPath.isEmpty()) {
+            int currentVertex = currentPath.peek();
+
+            if (tempGraph.containsKey(currentVertex) && !tempGraph.get(currentVertex).isEmpty()) {
+                int nextVertex = tempGraph.get(currentVertex).pollFirst();
+                tempGraph.get(nextVertex).remove(Integer.valueOf(currentVertex));
+                currentPath.push(nextVertex);
+            } else {
+                circuit.addFirst(currentVertex);
+                currentPath.pop();
+            }
+        }
+
+        return circuit;
+    }
+
+    private boolean isCoherentlyConnected() {
+        if (graph.isEmpty()) {
+            return true;
+        }
+
+        Set<Integer> visited = new HashSet<>();
+        int startNode = -1;
+
+        for (Map.Entry<Integer, LinkedList<Integer>> entry : graph.entrySet()) {
+            if (!entry.getValue().isEmpty()) {
+                startNode = entry.getKey();
+                break;
+            }
+        }
+
+        if (startNode == -1) {
+            return true;
+        }
+
+        dfs(startNode, visited);
+
+        for (Map.Entry<Integer, LinkedList<Integer>> entry : graph.entrySet()) {
+            if (!entry.getValue().isEmpty() && !visited.contains(entry.getKey())) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private void dfs(int u, Set<Integer> visited) {
+        visited.add(u);
+        if (graph.containsKey(u)) {
+            for (int v : graph.get(u)) {
+                if (!visited.contains(v)) {
+                    dfs(v, visited);
+                }
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/HierholzerAlgorithmTest.java b/src/test/java/com/thealgorithms/graph/HierholzerAlgorithmTest.java
new file mode 100644
index 000000000000..4dadb206d134
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/HierholzerAlgorithmTest.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import org.junit.jupiter.api.Test;
+
+public class HierholzerAlgorithmTest {
+
+    @Test
+    public void testFindsEulerianCircuitInSimpleTriangleGraph() {
+        Map<Integer, LinkedList<Integer>> graph = new HashMap<>();
+        graph.put(0, new LinkedList<>(Arrays.asList(1, 2)));
+        graph.put(1, new LinkedList<>(Arrays.asList(0, 2)));
+        graph.put(2, new LinkedList<>(Arrays.asList(0, 1)));
+        HierholzerAlgorithm algorithm = new HierholzerAlgorithm(graph);
+        assertTrue(algorithm.hasEulerianCircuit());
+        List<Integer> circuit = algorithm.findEulerianCircuit();
+        assertEquals(4, circuit.size());
+        assertEquals(circuit.get(0), circuit.get(circuit.size() - 1));
+    }
+
+    @Test
+    public void testFailsForGraphWithOddDegreeVertices() {
+        Map<Integer, LinkedList<Integer>> graph = new HashMap<>();
+        graph.put(0, new LinkedList<>(Collections.singletonList(1)));
+        graph.put(1, new LinkedList<>(Collections.singletonList(0)));
+        HierholzerAlgorithm algorithm = new HierholzerAlgorithm(graph);
+        assertFalse(algorithm.hasEulerianCircuit());
+        assertTrue(algorithm.findEulerianCircuit().isEmpty());
+    }
+
+    @Test
+    public void testFailsForDisconnectedGraph() {
+        Map<Integer, LinkedList<Integer>> graph = new HashMap<>();
+        graph.put(0, new LinkedList<>(Arrays.asList(1, 2)));
+        graph.put(1, new LinkedList<>(Arrays.asList(0, 2)));
+        graph.put(2, new LinkedList<>(Arrays.asList(0, 1)));
+        graph.put(3, new LinkedList<>(Arrays.asList(4, 5)));
+        graph.put(4, new LinkedList<>(Arrays.asList(3, 5)));
+        graph.put(5, new LinkedList<>(Arrays.asList(3, 4)));
+        HierholzerAlgorithm algorithm = new HierholzerAlgorithm(graph);
+        assertFalse(algorithm.hasEulerianCircuit());
+    }
+
+    @Test
+    public void testHandlesEmptyGraph() {
+        Map<Integer, LinkedList<Integer>> graph = new HashMap<>();
+        HierholzerAlgorithm algorithm = new HierholzerAlgorithm(graph);
+        assertTrue(algorithm.hasEulerianCircuit());
+        assertTrue(algorithm.findEulerianCircuit().isEmpty());
+    }
+}

From 82ff14c36e80e975970dd61ac9fa193a192fa973 Mon Sep 17 00:00:00 2001
From: Yajunesh MR <145507360+Yajunesh@users.noreply.github.com>
Date: Tue, 4 Nov 2025 02:42:24 +0530
Subject: [PATCH 1061/1338] feat: Add BitRotate utility for circular bit
 rotations (#7011)

* feat: Add BitRotate utility for circular bit rotations

* feat: Add BitRotate utility for circular bit rotations

* feat: Add BitRotate utility for circular bit rotations

* fix: Remove trailing spaces and add newline at EOF

---------

Co-authored-by: Yajunesh M R <yajunesh@Yajuneshs-MacBook-Pro.local>
---
 .../bitmanipulation/BitRotate.java            |  83 +++++++
 .../bitmanipulation/BitRotateTest.java        | 205 ++++++++++++++++++
 2 files changed, 288 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/bitmanipulation/BitRotate.java
 create mode 100644 src/test/java/com/thealgorithms/bitmanipulation/BitRotateTest.java

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/BitRotate.java b/src/main/java/com/thealgorithms/bitmanipulation/BitRotate.java
new file mode 100644
index 000000000000..226e09e78d1f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/bitmanipulation/BitRotate.java
@@ -0,0 +1,83 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * Utility class for performing circular bit rotations on 32-bit integers.
+ * Bit rotation is a circular shift operation where bits shifted out on one end
+ * are reinserted on the opposite end.
+ *
+ * <p>This class provides methods for both left and right circular rotations,
+ * supporting only 32-bit integer operations with proper shift normalization
+ * and error handling.</p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Bit_rotation">Bit Rotation</a>
+ */
+public final class BitRotate {
+
+    /**
+     * Private constructor to prevent instantiation.
+     * This is a utility class with only static methods.
+     */
+    private BitRotate() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+
+    /**
+     * Performs a circular left rotation (left shift) on a 32-bit integer.
+     * Bits shifted out from the left side are inserted on the right side.
+     *
+     * @param value the 32-bit integer value to rotate
+     * @param shift the number of positions to rotate left (must be non-negative)
+     * @return the result of left rotating the value by the specified shift amount
+     * @throws IllegalArgumentException if shift is negative
+     *
+     * @example
+     * // Binary: 10000000 00000000 00000000 00000001
+     * rotateLeft(0x80000001, 1)
+     * // Returns: 3 (binary: 00000000 00000000 00000000 00000011)
+     */
+    public static int rotateLeft(int value, int shift) {
+        if (shift < 0) {
+            throw new IllegalArgumentException("Shift amount cannot be negative: " + shift);
+        }
+
+        // Normalize shift to the range [0, 31] using modulo 32
+        shift = shift % 32;
+
+        if (shift == 0) {
+            return value;
+        }
+
+        // Left rotation: (value << shift) | (value >>> (32 - shift))
+        return (value << shift) | (value >>> (32 - shift));
+    }
+
+    /**
+     * Performs a circular right rotation (right shift) on a 32-bit integer.
+     * Bits shifted out from the right side are inserted on the left side.
+     *
+     * @param value the 32-bit integer value to rotate
+     * @param shift the number of positions to rotate right (must be non-negative)
+     * @return the result of right rotating the value by the specified shift amount
+     * @throws IllegalArgumentException if shift is negative
+     *
+     * @example
+     * // Binary: 00000000 00000000 00000000 00000011
+     * rotateRight(3, 1)
+     * // Returns: -2147483647 (binary: 10000000 00000000 00000000 00000001)
+     */
+    public static int rotateRight(int value, int shift) {
+        if (shift < 0) {
+            throw new IllegalArgumentException("Shift amount cannot be negative: " + shift);
+        }
+
+        // Normalize shift to the range [0, 31] using modulo 32
+        shift = shift % 32;
+
+        if (shift == 0) {
+            return value;
+        }
+
+        // Right rotation: (value >>> shift) | (value << (32 - shift))
+        return (value >>> shift) | (value << (32 - shift));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/BitRotateTest.java b/src/test/java/com/thealgorithms/bitmanipulation/BitRotateTest.java
new file mode 100644
index 000000000000..0595ae5a73e1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/bitmanipulation/BitRotateTest.java
@@ -0,0 +1,205 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for BitRotate class covering typical, boundary, and edge cases.
+ * Tests verify correct behavior for 32-bit circular bit rotations.
+ *
+ * @author Yajunesh
+ */
+public class BitRotateTest {
+
+    // ===== rotateLeft Tests =====
+
+    @Test
+    public void testRotateLeftBasic() {
+        // Basic left rotation
+        assertEquals(0b00000000_00000000_00000000_00000010, BitRotate.rotateLeft(1, 1));
+        assertEquals(0b00000000_00000000_00000000_00000100, BitRotate.rotateLeft(1, 2));
+        assertEquals(0b00000000_00000000_00000000_00001000, BitRotate.rotateLeft(1, 3));
+    }
+
+    @Test
+    public void testRotateLeftWithCarry() {
+        // Test bits carrying from left to right
+        // Binary: 10000000_00000000_00000000_00000001
+        int value = 0x80000001;
+        // After left rotate by 1: 00000000_00000000_00000000_00000011
+        assertEquals(3, BitRotate.rotateLeft(value, 1));
+
+        // Binary: 11000000_00000000_00000000_00000000
+        value = 0xC0000000;
+        // After left rotate by 1: 10000000_00000000_00000000_00000001
+        assertEquals(0x80000001, BitRotate.rotateLeft(value, 1));
+    }
+
+    @Test
+    public void testRotateLeftShift32() {
+        // Shift of 32 should be same as shift of 0 (modulo behavior)
+        int value = 0x12345678;
+        assertEquals(value, BitRotate.rotateLeft(value, 32));
+        assertEquals(value, BitRotate.rotateLeft(value, 64));
+        assertEquals(value, BitRotate.rotateLeft(value, 96));
+    }
+
+    @Test
+    public void testRotateLeftShiftNormalization() {
+        // Test that shifts > 32 are properly normalized
+        int value = 1;
+        assertEquals(BitRotate.rotateLeft(value, 1), BitRotate.rotateLeft(value, 33));
+        assertEquals(BitRotate.rotateLeft(value, 5), BitRotate.rotateLeft(value, 37));
+    }
+
+    @Test
+    public void testRotateLeftZeroShift() {
+        // Zero shift should return original value
+        int value = 0xABCD1234;
+        assertEquals(value, BitRotate.rotateLeft(value, 0));
+    }
+
+    // ===== rotateRight Tests =====
+
+    @Test
+    public void testRotateRightBasic() {
+        // Basic right rotation
+        assertEquals(0b10000000_00000000_00000000_00000000, BitRotate.rotateRight(1, 1));
+        assertEquals(0b01000000_00000000_00000000_00000000, BitRotate.rotateRight(1, 2));
+        assertEquals(0b00100000_00000000_00000000_00000000, BitRotate.rotateRight(1, 3));
+    }
+
+    @Test
+    public void testRotateRightWithCarry() {
+        // Test bits carrying from right to left
+        // Binary: 00000000_00000000_00000000_00000011
+        int value = 3;
+        // After right rotate by 1: 10000000_00000000_00000000_00000001
+        assertEquals(0x80000001, BitRotate.rotateRight(value, 1));
+
+        // Binary: 00000000_00000000_00000000_00000001
+        value = 1;
+        // After right rotate by 1: 10000000_00000000_00000000_00000000
+        assertEquals(0x80000000, BitRotate.rotateRight(value, 1));
+    }
+
+    @Test
+    public void testRotateRightShift32() {
+        // Shift of 32 should be same as shift of 0 (modulo behavior)
+        int value = 0x9ABCDEF0;
+        assertEquals(value, BitRotate.rotateRight(value, 32));
+        assertEquals(value, BitRotate.rotateRight(value, 64));
+        assertEquals(value, BitRotate.rotateRight(value, 96));
+    }
+
+    @Test
+    public void testRotateRightShiftNormalization() {
+        // Test that shifts > 32 are properly normalized
+        int value = 1;
+        assertEquals(BitRotate.rotateRight(value, 1), BitRotate.rotateRight(value, 33));
+        assertEquals(BitRotate.rotateRight(value, 7), BitRotate.rotateRight(value, 39));
+    }
+
+    @Test
+    public void testRotateRightZeroShift() {
+        // Zero shift should return original value
+        int value = 0xDEADBEEF;
+        assertEquals(value, BitRotate.rotateRight(value, 0));
+    }
+
+    // ===== Edge Case Tests =====
+
+    @Test
+    public void testRotateLeftMaxValue() {
+        // Test with maximum integer value
+        int value = Integer.MAX_VALUE; // 0x7FFFFFFF
+        int rotated = BitRotate.rotateLeft(value, 1);
+        // MAX_VALUE << 1 should become 0xFFFFFFFE, but with rotation it becomes different
+        assertEquals(0xFFFFFFFE, rotated);
+    }
+
+    @Test
+    public void testRotateRightMinValue() {
+        // Test with minimum integer value (treated as unsigned)
+        int value = Integer.MIN_VALUE; // 0x80000000
+        int rotated = BitRotate.rotateRight(value, 1);
+        // MIN_VALUE >>> 1 should become 0x40000000, but with rotation from left
+        assertEquals(0x40000000, rotated);
+    }
+
+    @Test
+    public void testRotateAllOnes() {
+        // Test with all bits set
+        int value = 0xFFFFFFFF; // All ones
+        assertEquals(value, BitRotate.rotateLeft(value, 13));
+        assertEquals(value, BitRotate.rotateRight(value, 27));
+    }
+
+    @Test
+    public void testRotateAllZeros() {
+        // Test with all bits zero
+        int value = 0x00000000;
+        assertEquals(value, BitRotate.rotateLeft(value, 15));
+        assertEquals(value, BitRotate.rotateRight(value, 19));
+    }
+
+    // ===== Exception Tests =====
+
+    @Test
+    public void testRotateLeftNegativeShift() {
+        // Negative shifts should throw IllegalArgumentException
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> BitRotate.rotateLeft(42, -1));
+        assertTrue(exception.getMessage().contains("negative"));
+    }
+
+    @Test
+    public void testRotateRightNegativeShift() {
+        // Negative shifts should throw IllegalArgumentException
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> BitRotate.rotateRight(42, -5));
+        assertTrue(exception.getMessage().contains("negative"));
+    }
+
+    // ===== Complementary Operations Test =====
+
+    @Test
+    public void testRotateLeftRightComposition() {
+        // Rotating left then right by same amount should return original value
+        int original = 0x12345678;
+        int shift = 7;
+
+        int leftRotated = BitRotate.rotateLeft(original, shift);
+        int restored = BitRotate.rotateRight(leftRotated, shift);
+
+        assertEquals(original, restored);
+    }
+
+    @Test
+    public void testRotateRightLeftComposition() {
+        // Rotating right then left by same amount should return original value
+        int original = 0x9ABCDEF0;
+        int shift = 13;
+
+        int rightRotated = BitRotate.rotateRight(original, shift);
+        int restored = BitRotate.rotateLeft(rightRotated, shift);
+
+        assertEquals(original, restored);
+    }
+
+    @Test
+    public void testRotateLeft31IsSameAsRotateRight1() {
+        // Rotating left by 31 should be same as rotating right by 1
+        int value = 0x55555555;
+        assertEquals(BitRotate.rotateLeft(value, 31), BitRotate.rotateRight(value, 1));
+    }
+
+    @Test
+    public void testTraversals() {
+        // Test that methods don't throw exceptions
+        assertDoesNotThrow(() -> BitRotate.rotateLeft(1, 1));
+        assertDoesNotThrow(() -> BitRotate.rotateRight(1, 1));
+    }
+}

From 100462d8e97295a5867a8efd6301bf45b19d80b9 Mon Sep 17 00:00:00 2001
From: Sourav Pati <k0259.mpsbls@gmail.com>
Date: Tue, 4 Nov 2025 02:59:44 +0530
Subject: [PATCH 1062/1338] Added LU Decomposition Algorithm for matrix (#6834)

* Added LU decomposition algorthm

* Added LU decomposition algorthim

* Added LU decomposition algorthim

* Added LU decomposition algorthim

* Added LU decomposition algorthim

* Added LU decomposition algorthim

* Added LU decomposition algorthim

* Added LU decomposition algorthim

* Added LU decomposition algorthim
---
 .../thealgorithms/matrix/LUDecomposition.java | 88 +++++++++++++++++++
 .../matrix/LUDecompositionTest.java           | 40 +++++++++
 2 files changed, 128 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/matrix/LUDecomposition.java
 create mode 100644 src/test/java/com/thealgorithms/matrix/LUDecompositionTest.java

diff --git a/src/main/java/com/thealgorithms/matrix/LUDecomposition.java b/src/main/java/com/thealgorithms/matrix/LUDecomposition.java
new file mode 100644
index 000000000000..e41aaa201338
--- /dev/null
+++ b/src/main/java/com/thealgorithms/matrix/LUDecomposition.java
@@ -0,0 +1,88 @@
+package com.thealgorithms.matrix;
+
+/**
+ * LU Decomposition algorithm
+ * --------------------------
+ * Decomposes a square matrix a into a product of two matrices:
+ * a = l * u
+ * where:
+ * - l is a lower triangular matrix with 1s on its diagonal
+ * - u is an upper triangular matrix
+ *
+ * Reference:
+ * https://en.wikipedia.org/wiki/lu_decomposition
+ */
+public final class LUDecomposition {
+
+    private LUDecomposition() {
+    }
+
+    /**
+     * A helper class to store both l and u matrices
+     */
+    public static class LU {
+        double[][] l;
+        double[][] u;
+
+        LU(double[][] l, double[][] u) {
+            this.l = l;
+            this.u = u;
+        }
+    }
+
+    /**
+     * Performs LU Decomposition on a square matrix a
+     *
+     * @param a input square matrix
+     * @return LU object containing l and u matrices
+     */
+    public static LU decompose(double[][] a) {
+        int n = a.length;
+        double[][] l = new double[n][n];
+        double[][] u = new double[n][n];
+
+        for (int i = 0; i < n; i++) {
+            // upper triangular matrix
+            for (int k = i; k < n; k++) {
+                double sum = 0;
+                for (int j = 0; j < i; j++) {
+                    sum += l[i][j] * u[j][k];
+                }
+                u[i][k] = a[i][k] - sum;
+            }
+
+            // lower triangular matrix
+            for (int k = i; k < n; k++) {
+                if (i == k) {
+                    l[i][i] = 1; // diagonal as 1
+                } else {
+                    double sum = 0;
+                    for (int j = 0; j < i; j++) {
+                        sum += l[k][j] * u[j][i];
+                    }
+                    l[k][i] = (a[k][i] - sum) / u[i][i];
+                }
+            }
+        }
+
+        return new LU(l, u);
+    }
+
+    /**
+     * Utility function to print a matrix
+     *
+     * @param m matrix to print
+     */
+    public static void printMatrix(double[][] m) {
+        for (double[] row : m) {
+            System.out.print("[");
+            for (int j = 0; j < row.length; j++) {
+                System.out.printf("%7.3f", row[j]);
+                if (j < row.length - 1) {
+                    System.out.print(", ");
+                }
+            }
+            System.out.println("]");
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/matrix/LUDecompositionTest.java b/src/test/java/com/thealgorithms/matrix/LUDecompositionTest.java
new file mode 100644
index 000000000000..d3cc6d64bf42
--- /dev/null
+++ b/src/test/java/com/thealgorithms/matrix/LUDecompositionTest.java
@@ -0,0 +1,40 @@
+package com.thealgorithms.matrix;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class LUDecompositionTest {
+
+    @Test
+    public void testLUDecomposition() {
+        double[][] a = {{4, 3}, {6, 3}};
+
+        // Perform LU decomposition
+        LUDecomposition.LU lu = LUDecomposition.decompose(a);
+        double[][] l = lu.l;
+        double[][] u = lu.u;
+
+        // Reconstruct a from l and u
+        double[][] reconstructed = multiplyMatrices(l, u);
+
+        // Assert that reconstructed matrix matches original a
+        for (int i = 0; i < a.length; i++) {
+            assertArrayEquals(a[i], reconstructed[i], 1e-9);
+        }
+    }
+
+    // Helper method to multiply two matrices
+    private double[][] multiplyMatrices(double[][] a, double[][] b) {
+        int n = a.length;
+        double[][] c = new double[n][n];
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < n; j++) {
+                for (int k = 0; k < n; k++) {
+                    c[i][j] += a[i][k] * b[k][j];
+                }
+            }
+        }
+        return c;
+    }
+}

From f0a437d08cfd8b8542d26793ad884b3af4e06206 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Date: Mon, 3 Nov 2025 23:26:10 +0100
Subject: [PATCH 1063/1338] Workflow/close failed prs (#6960)

* chore: add workflow to close stale PRs with failed workflows

* Include workflow failures when closing stale PRs

* Filter meaningful commits to only include those within the last 14 days
---
 .github/workflows/close-failed-prs.yml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/close-failed-prs.yml b/.github/workflows/close-failed-prs.yml
index f1bf3690f13f..6deea88f0daf 100644
--- a/.github/workflows/close-failed-prs.yml
+++ b/.github/workflows/close-failed-prs.yml
@@ -59,11 +59,13 @@ jobs:
 
                   const meaningfulCommits = commits.filter(c => {
                     const msg = c.commit.message.toLowerCase();
+                    const date = new Date(c.commit.committer.date);
                     const isMergeFromMain = mainBranches.some(branch =>
                       msg.startsWith(`merge branch '${branch}'`) ||
                       msg.includes(`merge remote-tracking branch '${branch}'`)
                     );
-                    return !isMergeFromMain;
+                      
+                    return !isMergeFromMain && date > cutoff;
                   });
 
                   // Get checks with error handling
@@ -151,4 +153,4 @@ jobs:
             } catch (error) {
               console.error(`❌ Fatal error: ${error.message}`);
               throw error;
-            }
\ No newline at end of file
+            }

From 5c965eb0977fbecb811e8f86d07a832bb75e3486 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 16:09:05 +0700
Subject: [PATCH 1064/1338] chore: fix typos in
 src/test/java/com/thealgorithms/datastructures (#7045)

Fix typos in src/test/java/com/thealgorithms/datastructures
---
 .../com/thealgorithms/datastructures/graphs/TwoSatTest.java | 2 +-
 .../datastructures/lists/SinglyLinkedListTest.java          | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/TwoSatTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/TwoSatTest.java
index 15e77b357f83..76b5aa8a780a 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/TwoSatTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/TwoSatTest.java
@@ -8,7 +8,7 @@
 
 /**
  * Testcases for 2-SAT.
- * Please note thea whlie checking for boolean assignments always keep n + 1 elements and the first element should be always false.
+ * Please note thea while checking for boolean assignments always keep n + 1 elements and the first element should be always false.
  */
 public class TwoSatTest {
     private TwoSat twoSat;
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
index f80c6b5055f0..fde52b982385 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SinglyLinkedListTest.java
@@ -214,10 +214,10 @@ void recursiveReverseListTest() {
 
     @Test
     void readWithEnhancedForLoopTest() {
-        final var expeced = new ArrayList<Integer>(Arrays.asList(10, 20, 30));
+        final var expected = new ArrayList<Integer>(Arrays.asList(10, 20, 30));
 
         SinglyLinkedList list = new SinglyLinkedList();
-        for (final var x : expeced) {
+        for (final var x : expected) {
             list.insert(x);
         }
 
@@ -226,7 +226,7 @@ void readWithEnhancedForLoopTest() {
             readElements.add(x);
         }
 
-        assertEquals(readElements, expeced);
+        assertEquals(readElements, expected);
     }
 
     @Test

From 2ff284960aab62b5b8d307f074552881605f769f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 16:25:18 +0700
Subject: [PATCH 1065/1338] chore: fix typos in
 src/main/java/com/thealgorithms/strings/Pangram.java (#7044)

Fix typos in src/main/java/com/thealgorithms/strings/Pangram.java

Co-authored-by: a 19151554+alxkm@users.noreply.github.com
---
 src/main/java/com/thealgorithms/strings/Pangram.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/strings/Pangram.java b/src/main/java/com/thealgorithms/strings/Pangram.java
index 01307b28f6c6..a92c282d7e52 100644
--- a/src/main/java/com/thealgorithms/strings/Pangram.java
+++ b/src/main/java/com/thealgorithms/strings/Pangram.java
@@ -60,7 +60,7 @@ public static boolean isPangram(String s) {
     }
 
     /**
-     * Checks if a String is Pangram or not by checking if each alhpabet is present or not
+     * Checks if a String is Pangram or not by checking if each alphabet is present or not
      *
      * @param s The String to check
      * @return {@code true} if s is a Pangram, otherwise {@code false}

From c42e73bd95cacc76de971aabaf37fce94d3105d1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 16:36:52 +0700
Subject: [PATCH 1066/1338] chore: fix typos in
 src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java
 (#7043)

Fix typos in src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java

Co-authored-by: a <19151554+alxkm@users.noreply.github.com>
---
 .../others/MemoryManagementAlgorithms.java             | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java b/src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java
index 0924b8569942..40a5f6a7a767 100644
--- a/src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java
+++ b/src/main/java/com/thealgorithms/others/MemoryManagementAlgorithms.java
@@ -16,7 +16,7 @@ public abstract class MemoryManagementAlgorithms {
      * blocks available.
      * @param sizeOfProcesses: an int array that contains the sizes of the
      * processes we need memory blocks for.
-     * @return the ArrayList filled with Integers repressenting the memory
+     * @return the ArrayList filled with Integers representing the memory
      * allocation that took place.
      */
     public abstract ArrayList<Integer> fitProcess(int[] sizeOfBlocks, int[] sizeOfProcesses);
@@ -91,7 +91,7 @@ private static int findBestFit(int[] blockSizes, int processSize) {
      * blocks available.
      * @param sizeOfProcesses: an int array that contains the sizes of the
      * processes we need memory blocks for.
-     * @return the ArrayList filled with Integers repressenting the memory
+     * @return the ArrayList filled with Integers representing the memory
      * allocation that took place.
      */
     public ArrayList<Integer> fitProcess(int[] sizeOfBlocks, int[] sizeOfProcesses) {
@@ -149,7 +149,7 @@ private static int findWorstFit(int[] blockSizes, int processSize) {
      * blocks available.
      * @param sizeOfProcesses: an int array that contains the sizes of the
      * processes we need memory blocks for.
-     * @return the ArrayList filled with Integers repressenting the memory
+     * @return the ArrayList filled with Integers representing the memory
      * allocation that took place.
      */
     public ArrayList<Integer> fitProcess(int[] sizeOfBlocks, int[] sizeOfProcesses) {
@@ -201,7 +201,7 @@ private static int findFirstFit(int[] blockSizes, int processSize) {
      * blocks available.
      * @param sizeOfProcesses: an int array that contains the sizes of the
      * processes we need memory blocks for.
-     * @return the ArrayList filled with Integers repressenting the memory
+     * @return the ArrayList filled with Integers representing the memory
      * allocation that took place.
      */
     public ArrayList<Integer> fitProcess(int[] sizeOfBlocks, int[] sizeOfProcesses) {
@@ -262,7 +262,7 @@ private int findNextFit(int[] blockSizes, int processSize) {
      * blocks available.
      * @param sizeOfProcesses: an int array that contains the sizes of the
      * processes we need memory blocks for.
-     * @return the ArrayList filled with Integers repressenting the memory
+     * @return the ArrayList filled with Integers representing the memory
      * allocation that took place.
      */
     public ArrayList<Integer> fitProcess(int[] sizeOfBlocks, int[] sizeOfProcesses) {

From a3717f0563e819c85d369d502ff03a0769d37593 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 16:43:02 +0700
Subject: [PATCH 1067/1338] chore: fix typos in
 src/main/java/com/thealgorithms/others/IterativeFloodFill.java (#7042)

Fix typos in src/main/java/com/thealgorithms/others/IterativeFloodFill.java
---
 .../java/com/thealgorithms/others/IterativeFloodFill.java | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/thealgorithms/others/IterativeFloodFill.java b/src/main/java/com/thealgorithms/others/IterativeFloodFill.java
index 3ef90369bd52..3f685f418a3d 100644
--- a/src/main/java/com/thealgorithms/others/IterativeFloodFill.java
+++ b/src/main/java/com/thealgorithms/others/IterativeFloodFill.java
@@ -32,8 +32,8 @@ private IterativeFloodFill() {
      * Iteratively fill the 2D image with new color
      *
      * @param image    The image to be filled
-     * @param x        The x co-ordinate at which color is to be filled
-     * @param y        The y co-ordinate at which color is to be filled
+     * @param x        The x coordinate at which color is to be filled
+     * @param y        The y coordinate at which color is to be filled
      * @param newColor The new color which to be filled in the image
      * @param oldColor The old color which is to be replaced in the image
      * @see <a href=https://www.geeksforgeeks.org/dsa/flood-fill-algorithm>FloodFill BFS<a/>
@@ -86,8 +86,8 @@ private static class Point {
      * Checks if a pixel should be skipped during flood fill operation.
      *
      * @param image    The image to get boundaries
-     * @param x        The x co-ordinate of pixel to check
-     * @param y        The y co-ordinate of pixel to check
+     * @param x        The x coordinate of pixel to check
+     * @param y        The y coordinate of pixel to check
      * @param oldColor The old color which is to be replaced in the image
      * @return {@code true} if pixel should be skipped, else {@code false}
      */

From 08ee26f2b8bbff2f71086b7ddb57a9000783c289 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 16:50:43 +0700
Subject: [PATCH 1068/1338] chore: fix typos in
 src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java
 (#7041)

Fix typos in src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java
---
 .../Implementing_auto_completing_features_using_trie.java       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java b/src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java
index bb88c7e3ae2f..7a1a7aadd805 100644
--- a/src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java
+++ b/src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java
@@ -97,7 +97,7 @@ static void suggestionsRec(TrieNode root, String currPrefix) {
         }
     }
 
-    // Fucntion  to print suggestions for
+    // Function  to print suggestions for
     // given query prefix.
     static int printAutoSuggestions(TrieNode root, final String query) {
         TrieNode pCrawl = root;

From d92ab9d89ca296a700cb56909b987f61e03ff484 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 16:56:34 +0700
Subject: [PATCH 1069/1338] chore: fix typos in
 src/main/java/com/thealgorithms/others/GaussLegendre.java (#7040)

Fix typos in src/main/java/com/thealgorithms/others/GaussLegendre.java
---
 src/main/java/com/thealgorithms/others/GaussLegendre.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/others/GaussLegendre.java b/src/main/java/com/thealgorithms/others/GaussLegendre.java
index b56b51f158fb..acf76ae3b192 100644
--- a/src/main/java/com/thealgorithms/others/GaussLegendre.java
+++ b/src/main/java/com/thealgorithms/others/GaussLegendre.java
@@ -1,7 +1,7 @@
 package com.thealgorithms.others;
 
 /**
- * Guass Legendre Algorithm ref
+ * Gauss Legendre Algorithm ref
  * https://en.wikipedia.org/wiki/Gauss–Legendre_algorithm
  *
  * @author AKS1996

From 26b47cb5b80c0faa9ead2460f2548b8cb32201dd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:02:56 +0700
Subject: [PATCH 1070/1338] chore: fix typos in
 src/main/java/com/thealgorithms/others/BankersAlgorithm.java (#7039)

Fix typos in src/main/java/com/thealgorithms/others/BankersAlgorithm.java
---
 src/main/java/com/thealgorithms/others/BankersAlgorithm.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/others/BankersAlgorithm.java b/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
index 836526529374..5abf633a1c12 100644
--- a/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/BankersAlgorithm.java
@@ -3,7 +3,7 @@
 import java.util.Scanner;
 
 /**
- * This file contains an implementation of BANKER'S ALGORITM Wikipedia:
+ * This file contains an implementation of BANKER'S ALGORITHM Wikipedia:
  * https://en.wikipedia.org/wiki/Banker%27s_algorithm
  *
  * The algorithm for finding out whether or not a system is in a safe state can

From 3b14d6d3987e4f52c73c3372cedc89ddae9ed895 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:13:26 +0700
Subject: [PATCH 1071/1338] chore: fix typos in
 src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java (#7038)

Fix typos in src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java
---
 .../java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java b/src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java
index 9a7f255282ac..7ee8a1a9f0ed 100644
--- a/src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java
+++ b/src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java
@@ -40,7 +40,7 @@ static void printMatrix(int[][] arr) {
 }
 
 /**
- * Class containing the algo to roate matrix by 90 degree
+ * Class containing the algo to rotate matrix by 90 degree
  */
 final class Rotate {
     private Rotate() {

From 1645f31e790b6c3ae36ddae81b654e6e5fbc0960 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:16:55 +0700
Subject: [PATCH 1072/1338] chore: fix typos in
 src/main/java/com/thealgorithms/maths/SieveOfAtkin.java (#7037)

Fix typos in src/main/java/com/thealgorithms/maths/SieveOfAtkin.java

Co-authored-by: a <19151554+alxkm@users.noreply.github.com>
---
 src/main/java/com/thealgorithms/maths/SieveOfAtkin.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/maths/SieveOfAtkin.java b/src/main/java/com/thealgorithms/maths/SieveOfAtkin.java
index ee59d0784ec4..780dd81dac7c 100644
--- a/src/main/java/com/thealgorithms/maths/SieveOfAtkin.java
+++ b/src/main/java/com/thealgorithms/maths/SieveOfAtkin.java
@@ -14,7 +14,7 @@
 public final class SieveOfAtkin {
 
     private SieveOfAtkin() {
-        // Utlity class; prevent instantiation
+        // Utility class; prevent instantiation
     }
 
     /**

From f403ce66f9894b7c15e786dc468eb52ac2ade5f4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:23:30 +0700
Subject: [PATCH 1073/1338] chore: fix typos in
 src/main/java/com/thealgorithms/maths/BinomialCoefficient.java (#7036)

Fix typos in src/main/java/com/thealgorithms/maths/BinomialCoefficient.java

Co-authored-by: a <19151554+alxkm@users.noreply.github.com>
---
 .../java/com/thealgorithms/maths/BinomialCoefficient.java     | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java b/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java
index faec049b08a7..1de39adbc18a 100644
--- a/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java
+++ b/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java
@@ -1,8 +1,8 @@
 package com.thealgorithms.maths;
 
 /*
- * Java program for Binomial Cofficients
- * Binomial Cofficients: A binomial cofficient C(n,k) gives number ways
+ * Java program for Binomial Coefficients
+ * Binomial Coefficients: A binomial coefficient C(n,k) gives number ways
  * in which k objects can be chosen from n objects.
  * Wikipedia: https://en.wikipedia.org/wiki/Binomial_coefficient
  *

From 500c5264519a389e57e8c094c876e414cb49be7f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:27:10 +0700
Subject: [PATCH 1074/1338] chore: fix typos in
 src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java
 (#7035)

Fix typos in src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java
---
 .../com/thealgorithms/divideandconquer/SkylineAlgorithm.java    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java b/src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java
index 610b1b78a36a..0e8d9442138c 100644
--- a/src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java
+++ b/src/main/java/com/thealgorithms/divideandconquer/SkylineAlgorithm.java
@@ -161,7 +161,7 @@ public int getY() {
          * function dominates the argument point.
          *
          * @param p1 the point that is compared
-         * @return true if the point wich calls the function dominates p1 false
+         * @return true if the point which calls the function dominates p1 false
          * otherwise.
          */
         public boolean dominates(Point p1) {

From 88c8e3935cf21dc97afc0298b519b0f19db3eeec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:31:34 +0700
Subject: [PATCH 1075/1338] chore: fix typos in
 src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java (#7034)

Fix typos in src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java

Co-authored-by: a <19151554+alxkm@users.noreply.github.com>
---
 .../java/com/thealgorithms/divideandconquer/ClosestPair.java    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java b/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java
index cd26f9213651..4c9c40c83174 100644
--- a/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java
+++ b/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java
@@ -182,7 +182,7 @@ public double closestPair(final Location[] a, final int indexNum) {
 
         double minLeftArea; // Minimum length of left array
         double minRightArea; // Minimum length of right array
-        double minValue; // Minimum lengt
+        double minValue; // Minimum length
 
         minLeftArea = closestPair(leftArray, divideX); // recursive closestPair
         minRightArea = closestPair(rightArray, indexNum - divideX);

From b87b1102d0f12219dc288707d6141b283839d676 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:35:18 +0700
Subject: [PATCH 1076/1338] chore: fix typos in
 src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java
 (#7028)

Fix typos in src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java

Co-authored-by: a <19151554+alxkm@users.noreply.github.com>
---
 .../datastructures/queues/PriorityQueues.java             | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java b/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java
index a5ca48670f2c..b877a5843b98 100644
--- a/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java
+++ b/src/main/java/com/thealgorithms/datastructures/queues/PriorityQueues.java
@@ -9,7 +9,7 @@
  * give numbers that are bigger, a higher priority. Queues in theory have no
  * fixed size but when using an array implementation it does.
  * <p>
- * Additional contibutions made by: PuneetTri(https://github.com/PuneetTri)
+ * Additional contributions made by: PuneetTri(https://github.com/PuneetTri)
  */
 class PriorityQueue {
 
@@ -32,8 +32,8 @@ class PriorityQueue {
 
     PriorityQueue() {
         /* If capacity is not defined, default size of 11 would be used
-         *  capacity=max+1 because we cant access 0th element of PQ, and to
-         *  accomodate (max)th elements we need capacity to be max+1.
+         *  capacity=max+1 because we can't access 0th element of PQ, and to
+         *  accommodate (max)th elements we need capacity to be max+1.
          *  Parent is at position k, child at position (k*2,k*2+1), if we
          *  use position 0 in our queue, its child would be at:
          *  (0*2, 0*2+1) -> (0,0). This is why we start at position 1
@@ -127,7 +127,7 @@ public int remove() {
         if (isEmpty()) {
             throw new RuntimeException("Queue is Empty");
         } else {
-            int max = queueArray[1]; // By defintion of our max-heap, value at queueArray[1] pos is
+            int max = queueArray[1]; // By definition of our max-heap, value at queueArray[1] pos is
                                      // the greatest
 
             // Swap max and last element

From 19f0f0bd83fb350004f375df180d3f65089013d8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:40:08 +0700
Subject: [PATCH 1077/1338] chore: fix typos in
 src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
 (#7024)

Fix typos in src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
---
 .../com/thealgorithms/conversions/TurkishToLatinConversion.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java b/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
index 30030de6c1bd..50726380621a 100644
--- a/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
+++ b/src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java
@@ -16,7 +16,7 @@ private TurkishToLatinConversion() {
      * 2. Replace all turkish characters with their corresponding latin characters
      * 3. Return the converted string
      *
-     * @param param String paramter
+     * @param param String parameter
      * @return String
      */
     public static String convertTurkishToLatin(String param) {

From dd01b35d973a7021b3d8a6a56cf9b21f61c49016 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:44:45 +0700
Subject: [PATCH 1078/1338] chore: fix typos in
 src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
 (#7025)

Fix typos in src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java

Co-authored-by: a <19151554+alxkm@users.noreply.github.com>
---
 .../com/thealgorithms/datastructures/graphs/BellmanFord.java    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
index 47c5f0d0b98e..5184dae58d28 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/BellmanFord.java
@@ -160,7 +160,7 @@ public void show(int source, int end,
                 break;
             }
         }
-        if (neg == 0) { // Go ahead and show results of computaion
+        if (neg == 0) { // Go ahead and show results of computation
             System.out.println("Distance is: " + dist[end]);
             System.out.println("Path followed:");
             System.out.print(source + " ");

From fab09e7da17325a99ef9033d585f978e26867435 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:48:33 +0700
Subject: [PATCH 1079/1338] chore: fix typos in
 src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
 (#7026)

Fix typos in src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java

Co-authored-by: a <19151554+alxkm@users.noreply.github.com>
---
 .../com/thealgorithms/datastructures/graphs/MatrixGraphs.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java b/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
index c1d47df457da..a54b0b75e4dc 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/MatrixGraphs.java
@@ -141,7 +141,7 @@ private int[][] adjacency() {
      *
      * @param from the parent vertex to check for adjacency
      * @param to the child vertex to check for adjacency
-     * @return whether or not the vertices are adjancent
+     * @return whether or not the vertices are adjacent
      */
     private boolean adjacencyOfEdgeDoesExist(int from, int to) {
         return (this.adjacency()[from][to] != AdjacencyMatrixGraph.EDGE_NONE);
@@ -162,7 +162,7 @@ public boolean vertexDoesExist(int aVertex) {
      *
      * @param from the parent vertex to check for adjacency
      * @param to the child vertex to check for adjacency
-     * @return whether or not the vertices are adjancent
+     * @return whether or not the vertices are adjacent
      */
     public boolean edgeDoesExist(int from, int to) {
         if (this.vertexDoesExist(from) && this.vertexDoesExist(to)) {

From 8ae57476b1298601c37da6742bb85902f2ac9b95 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:53:11 +0700
Subject: [PATCH 1080/1338] chore: fix typos in
 src/main/java/com/thealgorithms/devutils/nodes/TreeNode.java (#7033)

Fix typos in src/main/java/com/thealgorithms/devutils/nodes/TreeNode.java
---
 src/main/java/com/thealgorithms/devutils/nodes/TreeNode.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/devutils/nodes/TreeNode.java b/src/main/java/com/thealgorithms/devutils/nodes/TreeNode.java
index 13c9212306c1..1639bec6e5a0 100644
--- a/src/main/java/com/thealgorithms/devutils/nodes/TreeNode.java
+++ b/src/main/java/com/thealgorithms/devutils/nodes/TreeNode.java
@@ -12,7 +12,7 @@
 public abstract class TreeNode<E> extends Node<E> {
 
     /**
-     * Refernce to the parent Node.
+     * Reference to the parent Node.
      */
     private TreeNode<E> parentNode;
     /**
@@ -21,7 +21,7 @@ public abstract class TreeNode<E> extends Node<E> {
     private int depth;
 
     /**
-     * Empty contructor.
+     * Empty constructor.
      */
     public TreeNode() {
         super();

From 96304bda3008db17c2dab589c6415f25eb7aba06 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 17:56:44 +0700
Subject: [PATCH 1081/1338] chore: fix typos in
 src/main/java/com/thealgorithms/devutils/nodes/SimpleTreeNode.java (#7032)

Fix typos in src/main/java/com/thealgorithms/devutils/nodes/SimpleTreeNode.java
---
 .../com/thealgorithms/devutils/nodes/SimpleTreeNode.java    | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/devutils/nodes/SimpleTreeNode.java b/src/main/java/com/thealgorithms/devutils/nodes/SimpleTreeNode.java
index 215f01a6ef59..eefffacee8d6 100644
--- a/src/main/java/com/thealgorithms/devutils/nodes/SimpleTreeNode.java
+++ b/src/main/java/com/thealgorithms/devutils/nodes/SimpleTreeNode.java
@@ -11,16 +11,16 @@
 public class SimpleTreeNode<E> extends TreeNode<E> {
 
     /**
-     * Refrence to the child Node on the left.
+     * Reference to the child Node on the left.
      */
     private SimpleTreeNode<E> leftNode;
     /**
-     * Refrence to the child Node on the right.
+     * Reference to the child Node on the right.
      */
     private SimpleTreeNode<E> rightNode;
 
     /**
-     * Empty contructor.
+     * Empty constructor.
      */
     public SimpleTreeNode() {
         super();

From 65eeb5579e9a7c41a5037502b7d239e71e848ca4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 18:01:44 +0700
Subject: [PATCH 1082/1338] chore: fix typos in
 src/main/java/com/thealgorithms/devutils/nodes/SimpleNode.java (#7031)

Fix typos in src/main/java/com/thealgorithms/devutils/nodes/SimpleNode.java

Co-authored-by: a <19151554+alxkm@users.noreply.github.com>
---
 src/main/java/com/thealgorithms/devutils/nodes/SimpleNode.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/devutils/nodes/SimpleNode.java b/src/main/java/com/thealgorithms/devutils/nodes/SimpleNode.java
index 769ffc2a9a96..bf3e795dd74b 100644
--- a/src/main/java/com/thealgorithms/devutils/nodes/SimpleNode.java
+++ b/src/main/java/com/thealgorithms/devutils/nodes/SimpleNode.java
@@ -15,7 +15,7 @@ public class SimpleNode<E> extends Node<E> {
     private SimpleNode<E> nextNode;
 
     /**
-     * Empty contructor.
+     * Empty constructor.
      */
     public SimpleNode() {
         super();

From d75a66887033913b798be4a720f2b2b998f4f078 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 18:05:13 +0700
Subject: [PATCH 1083/1338] chore: fix typos in
 src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java
 (#7030)

Fix typos in src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java
---
 .../thealgorithms/datastructures/trees/BSTRecursiveGeneric.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java b/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java
index 0245372fe012..2c94224ddeb4 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java
@@ -30,7 +30,7 @@ public BSTRecursiveGeneric() {
     }
 
     /**
-     * Displays the tree is a structed format
+     * Displays the tree is a structured format
      */
     public void prettyDisplay() {
         prettyDisplay(root, 0);

From 0c277a1d9e1be23df1a0063ed5524f9640c15258 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 18:08:49 +0700
Subject: [PATCH 1084/1338] chore: fix typos in
 src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
 (#7027)

Fix typos in src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
---
 .../com/thealgorithms/datastructures/heaps/FibonacciHeap.java   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java b/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
index 7a263fc08ac5..834de9c77881 100644
--- a/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/FibonacciHeap.java
@@ -387,7 +387,7 @@ public class HeapNode {
         private HeapNode parent;
 
         /*
-         * a constructor for a heapNode withe key @param (key)
+         * a constructor for a heapNode with key @param (key)
          * prev == next == this
          * parent == child == null
          */

From 8c8527c2c8a8b68033937b565029bc36e15f1b7a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 18:12:14 +0700
Subject: [PATCH 1085/1338] chore: fix typos in
 src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java (#7029)

Fix typos in src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java
---
 .../java/com/thealgorithms/datastructures/trees/AVLSimple.java  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java b/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java
index e0309122cc12..07fc5c87b6c4 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/AVLSimple.java
@@ -1,7 +1,7 @@
 package com.thealgorithms.datastructures.trees;
 
 /*
-* Avl is algo that balance itself while adding new alues to tree
+* Avl is algo that balance itself while adding new values to tree
 * by rotating branches of binary tree and make itself Binary seaarch tree
 * there are four cases which has to tackle
 * rotating - left right ,left left,right right,right left

From 53230842f2e8bdff9cc7363b876a45a2de151bf6 Mon Sep 17 00:00:00 2001
From: Avaneeshakrishna <36323856+Avaneeshakrishna@users.noreply.github.com>
Date: Wed, 5 Nov 2025 03:22:39 -0800
Subject: [PATCH 1086/1338] add CombinationSum and test (#6725)

* add CombinationSum and test

* Format array and list literals in CombinationSumTest

* Fix sorting comparator in CombinationSumTest

* Refactor CombinationSum for better handling and clarity

Updated combinationSum method to handle null or empty candidates and improved variable naming for clarity.

* Fix sorting comparator in CombinationSumTest

* Update CombinationSumTest.java

* Fix sorting comparator for list of integers

* Fix formatting issues in CombinationSum class

* Change CombinationSum class to final

* Refactor norm method to accept Iterable instead of List

* Remove unnecessary whitespace in CombinationSumTest
---
 .../backtracking/CombinationSum.java          | 48 +++++++++++++++++++
 .../backtracking/CombinationSumTest.java      | 29 +++++++++++
 2 files changed, 77 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/backtracking/CombinationSum.java
 create mode 100644 src/test/java/com/thealgorithms/backtracking/CombinationSumTest.java

diff --git a/src/main/java/com/thealgorithms/backtracking/CombinationSum.java b/src/main/java/com/thealgorithms/backtracking/CombinationSum.java
new file mode 100644
index 000000000000..09b99032bdc1
--- /dev/null
+++ b/src/main/java/com/thealgorithms/backtracking/CombinationSum.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.backtracking;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/** Backtracking: pick/not-pick with reuse of candidates. */
+public final class CombinationSum {
+    private CombinationSum() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    public static List<List<Integer>> combinationSum(int[] candidates, int target) {
+        List<List<Integer>> results = new ArrayList<>();
+        if (candidates == null || candidates.length == 0) {
+            return results;
+        }
+
+        // Sort to help with pruning duplicates and early termination
+        Arrays.sort(candidates);
+        backtrack(candidates, target, 0, new ArrayList<>(), results);
+        return results;
+    }
+
+    private static void backtrack(int[] candidates, int remaining, int start, List<Integer> combination, List<List<Integer>> results) {
+        if (remaining == 0) {
+            // Found valid combination; add a copy
+            results.add(new ArrayList<>(combination));
+            return;
+        }
+
+        for (int i = start; i < candidates.length; i++) {
+            int candidate = candidates[i];
+
+            // If candidate is greater than remaining target, further candidates (sorted) will also be too big
+            if (candidate > remaining) {
+                break;
+            }
+
+            // include candidate
+            combination.add(candidate);
+            // Because we can reuse the same element, we pass i (not i + 1)
+            backtrack(candidates, remaining - candidate, i, combination, results);
+            // backtrack: remove last
+            combination.remove(combination.size() - 1);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/backtracking/CombinationSumTest.java b/src/test/java/com/thealgorithms/backtracking/CombinationSumTest.java
new file mode 100644
index 000000000000..986c71acebe8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/backtracking/CombinationSumTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.backtracking;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class CombinationSumTest {
+    private static List<List<Integer>> norm(Iterable<List<Integer>> x) {
+        List<List<Integer>> y = new ArrayList<>();
+        for (var p : x) {
+            var q = new ArrayList<>(p);
+            q.sort(Integer::compare);
+            y.add(q);
+        }
+        y.sort(Comparator.<List<Integer>>comparingInt(List::size).thenComparing(Object::toString));
+        return y;
+    }
+
+    @Test
+    void sample() {
+        int[] candidates = {2, 3, 6, 7};
+        int target = 7;
+        var expected = List.of(List.of(2, 2, 3), List.of(7));
+        assertEquals(norm(expected), norm(CombinationSum.combinationSum(candidates, target)));
+    }
+}

From 702664116d73dd8283c307bec606b6a31bdb70c6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 22:41:33 +0700
Subject: [PATCH 1087/1338] chore: fix typos in
 src/main/java/com/thealgorithms/backtracking/FloodFill.java (#7046)

Fix typos in src/main/java/com/thealgorithms/backtracking/FloodFill.java
---
 .../com/thealgorithms/backtracking/FloodFill.java    | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/FloodFill.java b/src/main/java/com/thealgorithms/backtracking/FloodFill.java
index c8219ca8ba7e..0f31a9c5a30e 100644
--- a/src/main/java/com/thealgorithms/backtracking/FloodFill.java
+++ b/src/main/java/com/thealgorithms/backtracking/FloodFill.java
@@ -12,8 +12,8 @@ private FloodFill() {
      * Get the color at the given coordinates of a 2D image
      *
      * @param image The image to be filled
-     * @param x The x co-ordinate of which color is to be obtained
-     * @param y The y co-ordinate of which color is to be obtained
+     * @param x The x coordinate of which color is to be obtained
+     * @param y The y coordinate of which color is to be obtained
      */
 
     public static int getPixel(final int[][] image, final int x, final int y) {
@@ -24,8 +24,8 @@ public static int getPixel(final int[][] image, final int x, final int y) {
      * Put the color at the given coordinates of a 2D image
      *
      * @param image The image to be filled
-     * @param x The x co-ordinate at which color is to be filled
-     * @param y The y co-ordinate at which color is to be filled
+     * @param x The x coordinate at which color is to be filled
+     * @param y The y coordinate at which color is to be filled
      */
     public static void putPixel(final int[][] image, final int x, final int y, final int newColor) {
         image[x][y] = newColor;
@@ -35,8 +35,8 @@ public static void putPixel(final int[][] image, final int x, final int y, final
      * Fill the 2D image with new color
      *
      * @param image The image to be filled
-     * @param x The x co-ordinate at which color is to be filled
-     * @param y The y co-ordinate at which color is to be filled
+     * @param x The x coordinate at which color is to be filled
+     * @param y The y coordinate at which color is to be filled
      * @param newColor The new color which to be filled in the image
      * @param oldColor The old color which is to be replaced in the image
      */

From 147da38888303b195c8d95a6f86dacfec9c5f665 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 22:45:27 +0700
Subject: [PATCH 1088/1338] chore: fix typos in
 src/main/java/com/thealgorithms/ciphers/AES.java (#7047)

Fix typos in src/main/java/com/thealgorithms/ciphers/AES.java

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 src/main/java/com/thealgorithms/ciphers/AES.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/AES.java b/src/main/java/com/thealgorithms/ciphers/AES.java
index 1c283f6b7655..df51eba55310 100644
--- a/src/main/java/com/thealgorithms/ciphers/AES.java
+++ b/src/main/java/com/thealgorithms/ciphers/AES.java
@@ -2738,7 +2738,7 @@ public static BigInteger decrypt(BigInteger cipherText, BigInteger key) {
 
     public static void main(String[] args) {
         try (Scanner input = new Scanner(System.in)) {
-            System.out.println("Enter (e) letter for encrpyt or (d) letter for decrypt :");
+            System.out.println("Enter (e) letter for encrypt or (d) letter for decrypt :");
             char choice = input.nextLine().charAt(0);
             String in;
             switch (choice) {

From c7cb54ed84f98e0d130caf3b4335c9eed69101d3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 22:49:00 +0700
Subject: [PATCH 1089/1338] chore: fix typos in
 src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
 (#7048)

Fix typos in src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
---
 .../datastructures/trees/CeilInBinarySearchTree.java          | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java b/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
index 214e111b9f1a..fff84111663b 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java
@@ -21,7 +21,7 @@
  *
  * Solution 1: Brute Force Solution: Do an inorder traversal and save result
  * into an array. Iterate over the array to get an element equal to or greater
- * than current key. Time Complexity: O(n) Space Complexity: O(n) for auxillary
+ * than current key. Time Complexity: O(n) Space Complexity: O(n) for auxiliary
  * array to save inorder representation of tree.
  * <p>
  * <p>
@@ -29,7 +29,7 @@
  * into an array.Since array is sorted do a binary search over the array to get
  * an element equal to or greater than current key. Time Complexity: O(n) for
  * traversal of tree and O(lg(n)) for binary search in array. Total = O(n) Space
- * Complexity: O(n) for auxillary array to save inorder representation of tree.
+ * Complexity: O(n) for auxiliary array to save inorder representation of tree.
  * <p>
  * <p>
  * Solution 3: Optimal We can do a DFS search on given tree in following

From d28fee96650f9a295708d813b2c135081bbfc6b8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Wed, 5 Nov 2025 22:53:18 +0700
Subject: [PATCH 1090/1338] chore: fix typos in
 src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java (#7049)

Fix typos in src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
---
 .../dynamicprogramming/BoundaryFill.java             | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java b/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
index 8494492f293f..ccd54ee4349a 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/BoundaryFill.java
@@ -12,8 +12,8 @@ private BoundaryFill() {
      * Get the color at the given co-odrinates of a 2D image
      *
      * @param image The image to be filled
-     * @param xCoordinate The x co-ordinate of which color is to be obtained
-     * @param yCoordinate The y co-ordinate of which color is to be obtained
+     * @param xCoordinate The x coordinate of which color is to be obtained
+     * @param yCoordinate The y coordinate of which color is to be obtained
      */
     public static int getPixel(int[][] image, int xCoordinate, int yCoordinate) {
         return image[xCoordinate][yCoordinate];
@@ -23,8 +23,8 @@ public static int getPixel(int[][] image, int xCoordinate, int yCoordinate) {
      * Put the color at the given co-odrinates of a 2D image
      *
      * @param image The image to be filed
-     * @param xCoordinate The x co-ordinate at which color is to be filled
-     * @param yCoordinate The y co-ordinate at which color is to be filled
+     * @param xCoordinate The x coordinate at which color is to be filled
+     * @param yCoordinate The y coordinate at which color is to be filled
      */
     public static void putPixel(int[][] image, int xCoordinate, int yCoordinate, int newColor) {
         image[xCoordinate][yCoordinate] = newColor;
@@ -34,8 +34,8 @@ public static void putPixel(int[][] image, int xCoordinate, int yCoordinate, int
      * Fill the 2D image with new color
      *
      * @param image The image to be filed
-     * @param xCoordinate The x co-ordinate at which color is to be filled
-     * @param yCoordinate The y co-ordinate at which color is to be filled
+     * @param xCoordinate The x coordinate at which color is to be filled
+     * @param yCoordinate The y coordinate at which color is to be filled
      * @param newColor The new color which to be filled in the image
      * @param boundaryColor The old color which is to be replaced in the image
      */

From d126fd59f7c4f9aac8de23db2766bc6f6121394d Mon Sep 17 00:00:00 2001
From: Arzoo1701 <122432635+Arzoo1701@users.noreply.github.com>
Date: Wed, 5 Nov 2025 23:11:08 +0530
Subject: [PATCH 1091/1338] Add Trapping Rainwater problem implementation (Two
 Pointer Approach) (#6990)

* Add Trapping Rainwater problem implementation (Two Pointer Approach)

* Add Wikipedia reference link for Trapping Rainwater problem

* fix: format TrappingRainwater.java for CI check

* fix: add package and resolve checkstyle errors for TrappingRainwater.java

* fix: declare TrappingRainwater as final to pass Checkstyle

* Add test cases for TrappingRainwater algorithm

* Add test cases for TrappingRainwater algorithm

* Move TrappingRainwater algorithm to stacks package

* Fix: Move TrappingRainwater to stacks and normalize newline in JugglerSequence

* Fix: Normalize newline in JugglerSequence to ensure test consistency

* Fix: Normalize newline in JugglerSequence and remove return statement

* Add JaCoCo plugin for code coverage reporting

* Revert pom.xml to original version from master

* Fix: Revert the pom.xml file

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 pom.xml                                       |  2 +-
 .../stacks/TrappingRainwater.java             | 48 +++++++++++++++++++
 .../stacks/TrappingRainwaterTest.java         | 38 +++++++++++++++
 3 files changed, 87 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/com/thealgorithms/stacks/TrappingRainwater.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/TrappingRainwaterTest.java

diff --git a/pom.xml b/pom.xml
index 825d86f8b239..7e936967208b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -155,4 +155,4 @@
             </plugin>
         </plugins>
     </build>
-</project>
+</project>
\ No newline at end of file
diff --git a/src/main/java/com/thealgorithms/stacks/TrappingRainwater.java b/src/main/java/com/thealgorithms/stacks/TrappingRainwater.java
new file mode 100644
index 000000000000..072665061b8e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/TrappingRainwater.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.stacks;
+/**
+ * Trapping Rainwater Problem
+ * Given an array of non-negative integers representing the height of bars,
+ * compute how much water it can trap after raining.
+ *
+ * Example:
+ * Input: [4,2,0,3,2,5]
+ * Output: 9
+ *
+ * Time Complexity: O(n)
+ * Space Complexity: O(1)
+ *
+ * Reference: https://en.wikipedia.org/wiki/Trapping_rain_water
+ */
+public final class TrappingRainwater {
+
+    private TrappingRainwater() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    public static int trap(int[] height) {
+        int left = 0;
+        int right = height.length - 1;
+        int leftMax = 0;
+        int rightMax = 0;
+        int result = 0;
+
+        while (left < right) {
+            if (height[left] < height[right]) {
+                if (height[left] >= leftMax) {
+                    leftMax = height[left];
+                } else {
+                    result += leftMax - height[left];
+                }
+                left++;
+            } else {
+                if (height[right] >= rightMax) {
+                    rightMax = height[right];
+                } else {
+                    result += rightMax - height[right];
+                }
+                right--;
+            }
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/TrappingRainwaterTest.java b/src/test/java/com/thealgorithms/stacks/TrappingRainwaterTest.java
new file mode 100644
index 000000000000..909be6cd46da
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/TrappingRainwaterTest.java
@@ -0,0 +1,38 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class TrappingRainwaterTest {
+
+    @Test
+    public void testExampleCase() {
+        int[] height = {4, 2, 0, 3, 2, 5};
+        assertEquals(9, TrappingRainwater.trap(height));
+    }
+
+    @Test
+    public void testNoTrapping() {
+        int[] height = {1, 2, 3, 4, 5};
+        assertEquals(0, TrappingRainwater.trap(height));
+    }
+
+    @Test
+    public void testFlatSurface() {
+        int[] height = {0, 0, 0, 0};
+        assertEquals(0, TrappingRainwater.trap(height));
+    }
+
+    @Test
+    public void testSymmetricPit() {
+        int[] height = {3, 0, 2, 0, 3};
+        assertEquals(7, TrappingRainwater.trap(height));
+    }
+
+    @Test
+    public void testSingleBar() {
+        int[] height = {5};
+        assertEquals(0, TrappingRainwater.trap(height));
+    }
+}

From 5a68ba93998c1ec4d0a201aba7e3d0ed942ae4c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Nam=20Kh=C3=A1nh?=
 <55955273+khanhkhanhlele@users.noreply.github.com>
Date: Thu, 6 Nov 2025 17:40:34 +0700
Subject: [PATCH 1092/1338] chore: fix typos in some files (#7052)

Fix typos in some files
---
 .../java/com/thealgorithms/datastructures/lists/README.md     | 2 +-
 .../java/com/thealgorithms/devutils/nodes/LargeTreeNode.java  | 4 ++--
 src/main/java/com/thealgorithms/others/CRCAlgorithm.java      | 4 ++--
 .../searches/RowColumnWiseSorted2dArrayBinarySearch.java      | 2 +-
 src/main/java/com/thealgorithms/sorts/LinkListSort.java       | 2 +-
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/README.md b/src/main/java/com/thealgorithms/datastructures/lists/README.md
index 5a19c3bfa990..5a0a43b923e1 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/README.md
+++ b/src/main/java/com/thealgorithms/datastructures/lists/README.md
@@ -28,6 +28,6 @@ The `next` variable points to the next node in the data structure and value stor
 4. `CreateAndDetectLoop.java` : Create and detect a loop in a linked list.
 5. `DoublyLinkedList.java` : A modification of singly linked list which has a `prev` pointer to point to the previous node.
 6. `MergeKSortedLinkedlist.java` : Merges K sorted linked list with mergesort (mergesort is also the most efficient sorting algorithm for linked list).
-7. `RandomNode.java` : Selects a random node from given linked list and diplays it.
+7. `RandomNode.java` : Selects a random node from given linked list and displays it.
 8. `SkipList.java` : Data Structure used for storing a sorted list of elements with help of a Linked list hierarchy that connects to subsequences of elements.
 9. `TortoiseHareAlgo.java` : Finds the middle element of a linked list using the fast and slow pointer (Tortoise-Hare) algorithm.
diff --git a/src/main/java/com/thealgorithms/devutils/nodes/LargeTreeNode.java b/src/main/java/com/thealgorithms/devutils/nodes/LargeTreeNode.java
index 95d53ecb1f7a..d69288f72200 100644
--- a/src/main/java/com/thealgorithms/devutils/nodes/LargeTreeNode.java
+++ b/src/main/java/com/thealgorithms/devutils/nodes/LargeTreeNode.java
@@ -3,7 +3,7 @@
 import java.util.Collection;
 
 /**
- * {@link TreeNode} extension that holds a {@link Collection} of refrences to
+ * {@link TreeNode} extension that holds a {@link Collection} of references to
  * child Nodes.
  *
  * @param <E> The type of the data held in the Node.
@@ -18,7 +18,7 @@ public class LargeTreeNode<E> extends TreeNode<E> {
     private Collection<LargeTreeNode<E>> childNodes;
 
     /**
-     * Empty contructor.
+     * Empty constructor.
      */
     public LargeTreeNode() {
         super();
diff --git a/src/main/java/com/thealgorithms/others/CRCAlgorithm.java b/src/main/java/com/thealgorithms/others/CRCAlgorithm.java
index 00ddc86be820..2d0be15e0a7b 100644
--- a/src/main/java/com/thealgorithms/others/CRCAlgorithm.java
+++ b/src/main/java/com/thealgorithms/others/CRCAlgorithm.java
@@ -95,7 +95,7 @@ public int getCorrectMess() {
 
     /**
      * Resets some of the object's values, used on the main function, so that it
-     * can be re-used, in order not to waste too much memory and time, by
+     * can be reused, in order not to waste too much memory and time, by
      * creating new objects.
      */
     public void refactor() {
@@ -171,7 +171,7 @@ public void divideMessageWithP(boolean check) {
      * Once the message is transmitted, some of it's elements, is possible to
      * change from 1 to 0, or from 0 to 1, because of the Bit Error Rate (ber).
      * For every element of the message, a random double number is created. If
-     * that number is smaller than ber, then the spesific element changes. On
+     * that number is smaller than ber, then the specific element changes. On
      * the other hand, if it's bigger than ber, it does not. Based on these
      * changes. the boolean variable messageChanged, gets the value: true, or
      * false.
diff --git a/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java b/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java
index b40c7554d84b..ecdcd36adf21 100644
--- a/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java
@@ -13,7 +13,7 @@
  * In this two pointers are taken, the first points to the 0th row and the second one points to end
  * column, and then the element corresponding to the pointers placed in the array is compared with
  * the target that either its equal, greater or smaller than the target. If the element is equal to
- * the target, the co-ordinates of that element is returned i.e. an array of the two pointers will
+ * the target, the coordinates of that element is returned i.e. an array of the two pointers will
  * be returned, else if the target is greater than corresponding element then the pointer pointing
  * to the 0th row will be incremented by 1, else if the target is lesser than the corresponding
  * element then the pointer pointing to the end column will be decremented by 1. And if the element
diff --git a/src/main/java/com/thealgorithms/sorts/LinkListSort.java b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
index 800d78f36549..d8fd76a86236 100644
--- a/src/main/java/com/thealgorithms/sorts/LinkListSort.java
+++ b/src/main/java/com/thealgorithms/sorts/LinkListSort.java
@@ -106,7 +106,7 @@ public static boolean isSorted(int[] p, int option) {
             // The given array and the expected array is checked if both are same then true
             // is displayed else false is displayed
         default:
-            // default is used incase user puts a unauthorized value
+            // default is used in case user puts a unauthorized value
             System.out.println("Wrong choice");
         }
         // Switch case is used to call the classes as per the user requirement

From 4951fb9ce23005150c0f32c3eadb615f1e96bbab Mon Sep 17 00:00:00 2001
From: Priyanshu Kumar Singh <priyanshu1303d@gmail.com>
Date: Thu, 6 Nov 2025 23:11:39 +0530
Subject: [PATCH 1093/1338] [FEAT] Add Kinematics (SUVAT) equations (#7053)

[FEAT] Add SUVAT equation for motion

Co-authored-by: Priyanshu1303d <priyanshu130d@gmail.com>
---
 .../com/thealgorithms/physics/Kinematics.java | 69 +++++++++++++++++++
 .../thealgorithms/physics/KinematicsTest.java | 48 +++++++++++++
 2 files changed, 117 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/physics/Kinematics.java
 create mode 100644 src/test/java/com/thealgorithms/physics/KinematicsTest.java

diff --git a/src/main/java/com/thealgorithms/physics/Kinematics.java b/src/main/java/com/thealgorithms/physics/Kinematics.java
new file mode 100644
index 000000000000..d017fe787afd
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/Kinematics.java
@@ -0,0 +1,69 @@
+package com.thealgorithms.physics;
+/**
+ * Implements the fundamental "SUVAT" equations for motion
+ * under constant acceleration.
+ *
+ * @author [Priyanshu Kumar Singh](https://github.com/Priyanshu1303d)
+ * @see <a href="https://en.wikipedia.org/wiki/Equations_of_motion#Uniform_acceleration">Wikipedia</a>
+ */
+public final class Kinematics {
+    private Kinematics() {
+    }
+
+    /**
+     * Calculates the final velocity (v) of an object.
+     * Formula: v = u + at
+     *
+     * @param u Initial velocity (m/s).
+     * @param a Constant acceleration (m/s^2).
+     * @param t Time elapsed (s).
+     * @return The final velocity (m/s).
+     */
+
+    public static double calculateFinalVelocity(double u, double a, double t) {
+        return u + a * t;
+    }
+
+    /**
+     * Calculates the displacement (s) of an object.
+     * Formula: s = ut + 0.5 * a * t^2
+     *
+     * @param u Initial velocity (m/s).
+     * @param a Constant acceleration (m/s^2).
+     * @param t Time elapsed (s).
+     * @return The displacement (m).
+     */
+
+    public static double calculateDisplacement(double u, double a, double t) {
+        return u * t + 0.5 * a * t * t;
+    }
+
+    /**
+     * Calculates the displacement (s) of an object.
+     * Formula: v^2 = u^2 + 2 * a * s
+     *
+     * @param u Initial velocity (m/s).
+     * @param a Constant acceleration (m/s^2).
+     * @param s Displacement (m).
+     * @return The final velocity squared (m/s)^2.
+     */
+
+    public static double calculateFinalVelocitySquared(double u, double a, double s) {
+        return u * u + 2 * a * s;
+    }
+
+    /**
+     * Calculates the displacement (s) using the average velocity.
+     * Formula: s = (u + v) / 2 * t
+     *
+     * @param u Initial velocity (m/s).
+     * @param v Final velocity (m/s).
+     * @param t Time elapsed (s).
+     * @return The displacement (m).
+     */
+
+    public static double calculateDisplacementFromVelocities(double u, double v, double t) {
+        double velocitySum = u + v;
+        return velocitySum / 2 * t;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/KinematicsTest.java b/src/test/java/com/thealgorithms/physics/KinematicsTest.java
new file mode 100644
index 000000000000..c5274b0814a7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/KinematicsTest.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the Kinematics utility class.
+ */
+
+public final class KinematicsTest {
+    // A small tolerance for comparing floating-point numbers
+    private static final double DELTA = 1e-9;
+    @Test
+    @DisplayName("Test final velocity: v = u + at")
+    void testCalculateFinalVelocity() {
+        assertEquals(20.0, Kinematics.calculateFinalVelocity(10.0, 2.0, 5.0), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test displacement: s = ut + 0.5at^2")
+    void testCalculateDisplacement() {
+        assertEquals(75.0, Kinematics.calculateDisplacement(10.0, 2.0, 5.0), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test final velocity squared: v^2 = u^2 + 2as")
+    void testCalculateFinalVelocitySquared() {
+        assertEquals(400.0, Kinematics.calculateFinalVelocitySquared(10.0, 2.0, 75.0), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test displacement from average velocity: s = (u+v)/2 * t")
+    void testCalculateDisplacementFromVelocities() {
+        assertEquals(75.0, Kinematics.calculateDisplacementFromVelocities(10.0, 20.0, 5.0), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test with negative acceleration (deceleration)")
+    void testDeceleration() {
+        assertEquals(10.0, Kinematics.calculateFinalVelocity(30.0, -4.0, 5.0), DELTA);
+        assertEquals(100.0, Kinematics.calculateDisplacement(30.0, -4.0, 5.0), DELTA);
+
+        assertEquals(100.0, Kinematics.calculateFinalVelocitySquared(30.0, -4.0, 100.0), DELTA);
+        assertEquals(100.0, Kinematics.calculateDisplacementFromVelocities(30.0, 10.0, 5.0), DELTA);
+    }
+}

From 2588af02057eff98541d859a9a90f30b91268457 Mon Sep 17 00:00:00 2001
From: PRINCE PATEL <princepatel260806@gmail.com>
Date: Fri, 7 Nov 2025 16:02:18 +0530
Subject: [PATCH 1094/1338] fix: Correct typo in ExponentialSearch filename
 (#7056)

---
 .../searches/{ExponentalSearch.java => ExponentialSearch.java}    | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename src/main/java/com/thealgorithms/searches/{ExponentalSearch.java => ExponentialSearch.java} (100%)

diff --git a/src/main/java/com/thealgorithms/searches/ExponentalSearch.java b/src/main/java/com/thealgorithms/searches/ExponentialSearch.java
similarity index 100%
rename from src/main/java/com/thealgorithms/searches/ExponentalSearch.java
rename to src/main/java/com/thealgorithms/searches/ExponentialSearch.java

From 0a5516569231f5c6daa48f9397447cf063c3d6ec Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 11 Nov 2025 13:03:51 +0100
Subject: [PATCH 1095/1338] chore(deps): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.6.15 to 7.7.0 (#7060)

* chore(deps): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.6.15 to 7.7.0.
- [Commits](https://github.com/mebigfatguy/fb-contrib/commits/v7.7.0)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.7.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* fix: suppress new warnings

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 pom.xml              | 2 +-
 spotbugs-exclude.xml | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 7e936967208b..e99c8762ea3d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -127,7 +127,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.15</version>
+                            <version>7.7.0</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index d2e094556d61..3e2f1ff84ca8 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -201,6 +201,12 @@
     <Match>
         <Bug pattern="SPP_FIELD_COULD_BE_STATIC" />
     </Match>
+    <Match>
+        <Bug pattern="ITC_INHERITANCE_TYPE_CHECKING" />
+    </Match>
+    <Match>
+        <Bug pattern="FII_USE_ARRAYS_STREAM" />
+    </Match>
     <!-- find-sec-bugs -->
     <Match>
         <Bug pattern="PREDICTABLE_RANDOM" />

From b709941eb688f5c5d4e442eb9ab64568c234814f Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 11 Nov 2025 22:30:27 +0100
Subject: [PATCH 1096/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 12.1.1 to 12.1.2 (#7063)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 12.1.1 to 12.1.2.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-12.1.1...checkstyle-12.1.2)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 12.1.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index e99c8762ea3d..6126bbe4d6c5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>12.1.1</version>
+                    <version>12.1.2</version>
                     </dependency>
                 </dependencies>
             </plugin>

From a008cc2b0889ed51bf47e673e5f056e97f64cae1 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Date: Wed, 12 Nov 2025 14:22:21 +0100
Subject: [PATCH 1097/1338] Update DIRECTORY.md (#6809)

Co-authored-by: DenizAltunkapan <DenizAltunkapan@users.noreply.github.com>
---
 DIRECTORY.md | 57 +++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 52 insertions(+), 5 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index eca2453fad0f..f15d65c18c3f 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -13,6 +13,7 @@
           - 📄 [AllPathsFromSourceToTarget](src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java)
           - 📄 [ArrayCombination](src/main/java/com/thealgorithms/backtracking/ArrayCombination.java)
           - 📄 [Combination](src/main/java/com/thealgorithms/backtracking/Combination.java)
+          - 📄 [CombinationSum](src/main/java/com/thealgorithms/backtracking/CombinationSum.java)
           - 📄 [CrosswordSolver](src/main/java/com/thealgorithms/backtracking/CrosswordSolver.java)
           - 📄 [FloodFill](src/main/java/com/thealgorithms/backtracking/FloodFill.java)
           - 📄 [KnightsTour](src/main/java/com/thealgorithms/backtracking/KnightsTour.java)
@@ -28,6 +29,7 @@
         - 📁 **bitmanipulation**
           - 📄 [BcdConversion](src/main/java/com/thealgorithms/bitmanipulation/BcdConversion.java)
           - 📄 [BinaryPalindromeCheck](src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java)
+          - 📄 [BitRotate](src/main/java/com/thealgorithms/bitmanipulation/BitRotate.java)
           - 📄 [BitSwap](src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java)
           - 📄 [BitwiseGCD](src/main/java/com/thealgorithms/bitmanipulation/BitwiseGCD.java)
           - 📄 [BooleanAlgebraGates](src/main/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGates.java)
@@ -93,6 +95,12 @@
             - 📄 [LFSR](src/main/java/com/thealgorithms/ciphers/a5/LFSR.java)
             - 📄 [Utils](src/main/java/com/thealgorithms/ciphers/a5/Utils.java)
         - 📁 **compression**
+          - 📄 [ArithmeticCoding](src/main/java/com/thealgorithms/compression/ArithmeticCoding.java)
+          - 📄 [BurrowsWheelerTransform](src/main/java/com/thealgorithms/compression/BurrowsWheelerTransform.java)
+          - 📄 [LZ77](src/main/java/com/thealgorithms/compression/LZ77.java)
+          - 📄 [LZ78](src/main/java/com/thealgorithms/compression/LZ78.java)
+          - 📄 [LZW](src/main/java/com/thealgorithms/compression/LZW.java)
+          - 📄 [MoveToFront](src/main/java/com/thealgorithms/compression/MoveToFront.java)
           - 📄 [RunLengthEncoding](src/main/java/com/thealgorithms/compression/RunLengthEncoding.java)
           - 📄 [ShannonFano](src/main/java/com/thealgorithms/compression/ShannonFano.java)
         - 📁 **conversions**
@@ -173,7 +181,6 @@
             - 📄 [FordFulkerson](src/main/java/com/thealgorithms/datastructures/graphs/FordFulkerson.java)
             - 📄 [Graphs](src/main/java/com/thealgorithms/datastructures/graphs/Graphs.java)
             - 📄 [HamiltonianCycle](src/main/java/com/thealgorithms/datastructures/graphs/HamiltonianCycle.java)
-            - 📄 [HierholzerAlgorithm](src/main/java/com/thealgorithms/graph/HierholzerAlgorithm.java)
             - 📄 [JohnsonsAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/JohnsonsAlgorithm.java)
             - 📄 [KahnsAlgorithm](src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java)
             - 📄 [Kosaraju](src/main/java/com/thealgorithms/datastructures/graphs/Kosaraju.java)
@@ -358,8 +365,10 @@
           - 📄 [WildcardMatching](src/main/java/com/thealgorithms/dynamicprogramming/WildcardMatching.java)
           - 📄 [WineProblem](src/main/java/com/thealgorithms/dynamicprogramming/WineProblem.java)
         - 📁 **geometry**
+          - 📄 [BentleyOttmann](src/main/java/com/thealgorithms/geometry/BentleyOttmann.java)
           - 📄 [BresenhamLine](src/main/java/com/thealgorithms/geometry/BresenhamLine.java)
           - 📄 [ConvexHull](src/main/java/com/thealgorithms/geometry/ConvexHull.java)
+          - 📄 [DDALine](src/main/java/com/thealgorithms/geometry/DDALine.java)
           - 📄 [GrahamScan](src/main/java/com/thealgorithms/geometry/GrahamScan.java)
           - 📄 [Haversine](src/main/java/com/thealgorithms/geometry/Haversine.java)
           - 📄 [MidpointCircle](src/main/java/com/thealgorithms/geometry/MidpointCircle.java)
@@ -372,10 +381,13 @@
           - 📄 [Dinic](src/main/java/com/thealgorithms/graph/Dinic.java)
           - 📄 [Edmonds](src/main/java/com/thealgorithms/graph/Edmonds.java)
           - 📄 [EdmondsKarp](src/main/java/com/thealgorithms/graph/EdmondsKarp.java)
+          - 📄 [HierholzerAlgorithm](src/main/java/com/thealgorithms/graph/HierholzerAlgorithm.java)
+          - 📄 [HierholzerEulerianPath](src/main/java/com/thealgorithms/graph/HierholzerEulerianPath.java)
           - 📄 [HopcroftKarp](src/main/java/com/thealgorithms/graph/HopcroftKarp.java)
           - 📄 [HungarianAlgorithm](src/main/java/com/thealgorithms/graph/HungarianAlgorithm.java)
           - 📄 [PredecessorConstrainedDfs](src/main/java/com/thealgorithms/graph/PredecessorConstrainedDfs.java)
           - 📄 [PushRelabel](src/main/java/com/thealgorithms/graph/PushRelabel.java)
+          - 📄 [StoerWagner](src/main/java/com/thealgorithms/graph/StoerWagner.java)
           - 📄 [StronglyConnectedComponentOptimized](src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java)
           - 📄 [TravelingSalesman](src/main/java/com/thealgorithms/graph/TravelingSalesman.java)
           - 📄 [YensKShortestPaths](src/main/java/com/thealgorithms/graph/YensKShortestPaths.java)
@@ -420,6 +432,7 @@
           - 📄 [BinomialCoefficient](src/main/java/com/thealgorithms/maths/BinomialCoefficient.java)
           - 📄 [CatalanNumbers](src/main/java/com/thealgorithms/maths/CatalanNumbers.java)
           - 📄 [Ceil](src/main/java/com/thealgorithms/maths/Ceil.java)
+          - 📄 [ChebyshevIteration](src/main/java/com/thealgorithms/maths/ChebyshevIteration.java)
           - 📄 [ChineseRemainderTheorem](src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java)
           - 📄 [CircularConvolutionFFT](src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java)
           - 📄 [CollatzConjecture](src/main/java/com/thealgorithms/maths/CollatzConjecture.java)
@@ -478,6 +491,7 @@
           - 📄 [Median](src/main/java/com/thealgorithms/maths/Median.java)
           - 📄 [MinValue](src/main/java/com/thealgorithms/maths/MinValue.java)
           - 📄 [Mode](src/main/java/com/thealgorithms/maths/Mode.java)
+          - 📄 [Neville](src/main/java/com/thealgorithms/maths/Neville.java)
           - 📄 [NonRepeatingElement](src/main/java/com/thealgorithms/maths/NonRepeatingElement.java)
           - 📄 [NthUglyNumber](src/main/java/com/thealgorithms/maths/NthUglyNumber.java)
           - 📄 [NumberOfDigits](src/main/java/com/thealgorithms/maths/NumberOfDigits.java)
@@ -531,6 +545,7 @@
           - 📄 [ZellersCongruence](src/main/java/com/thealgorithms/maths/ZellersCongruence.java)
         - 📁 **matrix**
           - 📄 [InverseOfMatrix](src/main/java/com/thealgorithms/matrix/InverseOfMatrix.java)
+          - 📄 [LUDecomposition](src/main/java/com/thealgorithms/matrix/LUDecomposition.java)
           - 📄 [MatrixMultiplication](src/main/java/com/thealgorithms/matrix/MatrixMultiplication.java)
           - 📄 [MatrixRank](src/main/java/com/thealgorithms/matrix/MatrixRank.java)
           - 📄 [MatrixTranspose](src/main/java/com/thealgorithms/matrix/MatrixTranspose.java)
@@ -591,7 +606,6 @@
           - 📄 [PageRank](src/main/java/com/thealgorithms/others/PageRank.java)
           - 📄 [PasswordGen](src/main/java/com/thealgorithms/others/PasswordGen.java)
           - 📄 [PerlinNoise](src/main/java/com/thealgorithms/others/PerlinNoise.java)
-          - 📄 [PrintAMatrixInSpiralOrder](src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java)
           - 📄 [QueueUsingTwoStacks](src/main/java/com/thealgorithms/others/QueueUsingTwoStacks.java)
           - 📄 [SkylineProblem](src/main/java/com/thealgorithms/others/SkylineProblem.java)
           - 📄 [TwoPointers](src/main/java/com/thealgorithms/others/TwoPointers.java)
@@ -599,7 +613,14 @@
           - 📁 **cn**
             - 📄 [HammingDistance](src/main/java/com/thealgorithms/others/cn/HammingDistance.java)
         - 📁 **physics**
+          - 📄 [CoulombsLaw](src/main/java/com/thealgorithms/physics/CoulombsLaw.java)
+          - 📄 [DampedOscillator](src/main/java/com/thealgorithms/physics/DampedOscillator.java)
+          - 📄 [ElasticCollision2D](src/main/java/com/thealgorithms/physics/ElasticCollision2D.java)
+          - 📄 [Gravitation](src/main/java/com/thealgorithms/physics/Gravitation.java)
           - 📄 [GroundToGroundProjectileMotion](src/main/java/com/thealgorithms/physics/GroundToGroundProjectileMotion.java)
+          - 📄 [Kinematics](src/main/java/com/thealgorithms/physics/Kinematics.java)
+          - 📄 [ProjectileMotion](src/main/java/com/thealgorithms/physics/ProjectileMotion.java)
+          - 📄 [SimplePendulumRK4](src/main/java/com/thealgorithms/physics/SimplePendulumRK4.java)
         - 📁 **puzzlesandgames**
           - 📄 [Sudoku](src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java)
           - 📄 [TowerOfHanoi](src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java)
@@ -649,7 +670,7 @@
           - 📄 [BoyerMoore](src/main/java/com/thealgorithms/searches/BoyerMoore.java)
           - 📄 [BreadthFirstSearch](src/main/java/com/thealgorithms/searches/BreadthFirstSearch.java)
           - 📄 [DepthFirstSearch](src/main/java/com/thealgorithms/searches/DepthFirstSearch.java)
-          - 📄 [ExponentalSearch](src/main/java/com/thealgorithms/searches/ExponentalSearch.java)
+          - 📄 [ExponentialSearch](src/main/java/com/thealgorithms/searches/ExponentialSearch.java)
           - 📄 [FibonacciSearch](src/main/java/com/thealgorithms/searches/FibonacciSearch.java)
           - 📄 [HowManyTimesRotated](src/main/java/com/thealgorithms/searches/HowManyTimesRotated.java)
           - 📄 [InterpolationSearch](src/main/java/com/thealgorithms/searches/InterpolationSearch.java)
@@ -758,6 +779,7 @@
           - 📄 [SortStack](src/main/java/com/thealgorithms/stacks/SortStack.java)
           - 📄 [StackPostfixNotation](src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
           - 📄 [StackUsingTwoQueues](src/main/java/com/thealgorithms/stacks/StackUsingTwoQueues.java)
+          - 📄 [TrappingRainwater](src/main/java/com/thealgorithms/stacks/TrappingRainwater.java)
         - 📁 **strings**
           - 📄 [AhoCorasick](src/main/java/com/thealgorithms/strings/AhoCorasick.java)
           - 📄 [Alphabetical](src/main/java/com/thealgorithms/strings/Alphabetical.java)
@@ -808,6 +830,7 @@
         - 📁 **backtracking**
           - 📄 [AllPathsFromSourceToTargetTest](src/test/java/com/thealgorithms/backtracking/AllPathsFromSourceToTargetTest.java)
           - 📄 [ArrayCombinationTest](src/test/java/com/thealgorithms/backtracking/ArrayCombinationTest.java)
+          - 📄 [CombinationSumTest](src/test/java/com/thealgorithms/backtracking/CombinationSumTest.java)
           - 📄 [CombinationTest](src/test/java/com/thealgorithms/backtracking/CombinationTest.java)
           - 📄 [CrosswordSolverTest](src/test/java/com/thealgorithms/backtracking/CrosswordSolverTest.java)
           - 📄 [FloodFillTest](src/test/java/com/thealgorithms/backtracking/FloodFillTest.java)
@@ -824,6 +847,7 @@
         - 📁 **bitmanipulation**
           - 📄 [BcdConversionTest](src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java)
           - 📄 [BinaryPalindromeCheckTest](src/test/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheckTest.java)
+          - 📄 [BitRotateTest](src/test/java/com/thealgorithms/bitmanipulation/BitRotateTest.java)
           - 📄 [BitSwapTest](src/test/java/com/thealgorithms/bitmanipulation/BitSwapTest.java)
           - 📄 [BitwiseGCDTest](src/test/java/com/thealgorithms/bitmanipulation/BitwiseGCDTest.java)
           - 📄 [BooleanAlgebraGatesTest](src/test/java/com/thealgorithms/bitmanipulation/BooleanAlgebraGatesTest.java)
@@ -884,6 +908,12 @@
             - 📄 [A5KeyStreamGeneratorTest](src/test/java/com/thealgorithms/ciphers/a5/A5KeyStreamGeneratorTest.java)
             - 📄 [LFSRTest](src/test/java/com/thealgorithms/ciphers/a5/LFSRTest.java)
         - 📁 **compression**
+          - 📄 [ArithmeticCodingTest](src/test/java/com/thealgorithms/compression/ArithmeticCodingTest.java)
+          - 📄 [BurrowsWheelerTransformTest](src/test/java/com/thealgorithms/compression/BurrowsWheelerTransformTest.java)
+          - 📄 [LZ77Test](src/test/java/com/thealgorithms/compression/LZ77Test.java)
+          - 📄 [LZ78Test](src/test/java/com/thealgorithms/compression/LZ78Test.java)
+          - 📄 [LZWTest](src/test/java/com/thealgorithms/compression/LZWTest.java)
+          - 📄 [MoveToFrontTest](src/test/java/com/thealgorithms/compression/MoveToFrontTest.java)
           - 📄 [RunLengthEncodingTest](src/test/java/com/thealgorithms/compression/RunLengthEncodingTest.java)
           - 📄 [ShannonFanoTest](src/test/java/com/thealgorithms/compression/ShannonFanoTest.java)
         - 📁 **conversions**
@@ -1114,8 +1144,10 @@
           - 📄 [WildcardMatchingTest](src/test/java/com/thealgorithms/dynamicprogramming/WildcardMatchingTest.java)
           - 📄 [WineProblemTest](src/test/java/com/thealgorithms/dynamicprogramming/WineProblemTest.java)
         - 📁 **geometry**
+          - 📄 [BentleyOttmannTest](src/test/java/com/thealgorithms/geometry/BentleyOttmannTest.java)
           - 📄 [BresenhamLineTest](src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java)
           - 📄 [ConvexHullTest](src/test/java/com/thealgorithms/geometry/ConvexHullTest.java)
+          - 📄 [DDALineTest](src/test/java/com/thealgorithms/geometry/DDALineTest.java)
           - 📄 [GrahamScanTest](src/test/java/com/thealgorithms/geometry/GrahamScanTest.java)
           - 📄 [HaversineTest](src/test/java/com/thealgorithms/geometry/HaversineTest.java)
           - 📄 [MidpointCircleTest](src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java)
@@ -1128,9 +1160,13 @@
           - 📄 [DinicTest](src/test/java/com/thealgorithms/graph/DinicTest.java)
           - 📄 [EdmondsKarpTest](src/test/java/com/thealgorithms/graph/EdmondsKarpTest.java)
           - 📄 [EdmondsTest](src/test/java/com/thealgorithms/graph/EdmondsTest.java)
+          - 📄 [HierholzerAlgorithmTest](src/test/java/com/thealgorithms/graph/HierholzerAlgorithmTest.java)
+          - 📄 [HierholzerEulerianPathTest](src/test/java/com/thealgorithms/graph/HierholzerEulerianPathTest.java)
           - 📄 [HopcroftKarpTest](src/test/java/com/thealgorithms/graph/HopcroftKarpTest.java)
+          - 📄 [HungarianAlgorithmTest](src/test/java/com/thealgorithms/graph/HungarianAlgorithmTest.java)
           - 📄 [PredecessorConstrainedDfsTest](src/test/java/com/thealgorithms/graph/PredecessorConstrainedDfsTest.java)
           - 📄 [PushRelabelTest](src/test/java/com/thealgorithms/graph/PushRelabelTest.java)
+          - 📄 [StoerWagnerTest](src/test/java/com/thealgorithms/graph/StoerWagnerTest.java)
           - 📄 [StronglyConnectedComponentOptimizedTest](src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)
           - 📄 [TravelingSalesmanTest](src/test/java/com/thealgorithms/graph/TravelingSalesmanTest.java)
           - 📄 [YensKShortestPathsTest](src/test/java/com/thealgorithms/graph/YensKShortestPathsTest.java)
@@ -1172,6 +1208,7 @@
           - 📄 [BinomialCoefficientTest](src/test/java/com/thealgorithms/maths/BinomialCoefficientTest.java)
           - 📄 [CatalanNumbersTest](src/test/java/com/thealgorithms/maths/CatalanNumbersTest.java)
           - 📄 [CeilTest](src/test/java/com/thealgorithms/maths/CeilTest.java)
+          - 📄 [ChebyshevIterationTest](src/test/java/com/thealgorithms/maths/ChebyshevIterationTest.java)
           - 📄 [ChineseRemainderTheoremTest](src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java)
           - 📄 [CollatzConjectureTest](src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
           - 📄 [CombinationsTest](src/test/java/com/thealgorithms/maths/CombinationsTest.java)
@@ -1211,6 +1248,7 @@
           - 📄 [HarshadNumberTest](src/test/java/com/thealgorithms/maths/HarshadNumberTest.java)
           - 📄 [HeronsFormulaTest](src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java)
           - 📄 [JosephusProblemTest](src/test/java/com/thealgorithms/maths/JosephusProblemTest.java)
+          - 📄 [JugglerSequenceTest](src/test/java/com/thealgorithms/maths/JugglerSequenceTest.java)
           - 📄 [KaprekarNumbersTest](src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java)
           - 📄 [KaratsubaMultiplicationTest](src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java)
           - 📄 [KeithNumberTest](src/test/java/com/thealgorithms/maths/KeithNumberTest.java)
@@ -1226,6 +1264,7 @@
           - 📄 [MedianTest](src/test/java/com/thealgorithms/maths/MedianTest.java)
           - 📄 [MinValueTest](src/test/java/com/thealgorithms/maths/MinValueTest.java)
           - 📄 [ModeTest](src/test/java/com/thealgorithms/maths/ModeTest.java)
+          - 📄 [NevilleTest](src/test/java/com/thealgorithms/maths/NevilleTest.java)
           - 📄 [NonRepeatingElementTest](src/test/java/com/thealgorithms/maths/NonRepeatingElementTest.java)
           - 📄 [NthUglyNumberTest](src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java)
           - 📄 [NumberOfDigitsTest](src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java)
@@ -1275,14 +1314,15 @@
             - 📄 [PrimeFactorizationTest](src/test/java/com/thealgorithms/maths/prime/PrimeFactorizationTest.java)
         - 📁 **matrix**
           - 📄 [InverseOfMatrixTest](src/test/java/com/thealgorithms/matrix/InverseOfMatrixTest.java)
+          - 📄 [LUDecompositionTest](src/test/java/com/thealgorithms/matrix/LUDecompositionTest.java)
           - 📄 [MatrixMultiplicationTest](src/test/java/com/thealgorithms/matrix/MatrixMultiplicationTest.java)
           - 📄 [MatrixRankTest](src/test/java/com/thealgorithms/matrix/MatrixRankTest.java)
           - 📄 [MatrixTransposeTest](src/test/java/com/thealgorithms/matrix/MatrixTransposeTest.java)
           - 📄 [MatrixUtilTest](src/test/java/com/thealgorithms/matrix/MatrixUtilTest.java)
           - 📄 [MedianOfMatrixTest](src/test/java/com/thealgorithms/matrix/MedianOfMatrixTest.java)
           - 📄 [MirrorOfMatrixTest](src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java)
+          - 📄 [PrintAMatrixInSpiralOrderTest](src/test/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrderTest.java)
           - 📄 [SolveSystemTest](src/test/java/com/thealgorithms/matrix/SolveSystemTest.java)
-          - 📄 [TestPrintMatrixInSpiralOrder](src/test/java/com/thealgorithms/matrix/TestPrintMatrixInSpiralOrder.java)
         - 📁 **misc**
           - 📄 [ColorContrastRatioTest](src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java)
           - 📄 [MapReduceTest](src/test/java/com/thealgorithms/misc/MapReduceTest.java)
@@ -1323,13 +1363,19 @@
           - 📄 [PerlinNoiseTest](src/test/java/com/thealgorithms/others/PerlinNoiseTest.java)
           - 📄 [QueueUsingTwoStacksTest](src/test/java/com/thealgorithms/others/QueueUsingTwoStacksTest.java)
           - 📄 [SkylineProblemTest](src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
-          - 📄 [TestPrintMatrixInSpiralOrder](src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
           - 📄 [TwoPointersTest](src/test/java/com/thealgorithms/others/TwoPointersTest.java)
           - 📄 [WorstFitCPUTest](src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
           - 📁 **cn**
             - 📄 [HammingDistanceTest](src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java)
         - 📁 **physics**
+          - 📄 [CoulombsLawTest](src/test/java/com/thealgorithms/physics/CoulombsLawTest.java)
+          - 📄 [DampedOscillatorTest](src/test/java/com/thealgorithms/physics/DampedOscillatorTest.java)
+          - 📄 [ElasticCollision2DTest](src/test/java/com/thealgorithms/physics/ElasticCollision2DTest.java)
+          - 📄 [GravitationTest](src/test/java/com/thealgorithms/physics/GravitationTest.java)
           - 📄 [GroundToGroundProjectileMotionTest](src/test/java/com/thealgorithms/physics/GroundToGroundProjectileMotionTest.java)
+          - 📄 [KinematicsTest](src/test/java/com/thealgorithms/physics/KinematicsTest.java)
+          - 📄 [ProjectileMotionTest](src/test/java/com/thealgorithms/physics/ProjectileMotionTest.java)
+          - 📄 [SimplePendulumRK4Test](src/test/java/com/thealgorithms/physics/SimplePendulumRK4Test.java)
         - 📁 **puzzlesandgames**
           - 📄 [SudokuTest](src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java)
           - 📄 [TowerOfHanoiTest](src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java)
@@ -1487,6 +1533,7 @@
           - 📄 [SortStackTest](src/test/java/com/thealgorithms/stacks/SortStackTest.java)
           - 📄 [StackPostfixNotationTest](src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
           - 📄 [StackUsingTwoQueuesTest](src/test/java/com/thealgorithms/stacks/StackUsingTwoQueuesTest.java)
+          - 📄 [TrappingRainwaterTest](src/test/java/com/thealgorithms/stacks/TrappingRainwaterTest.java)
         - 📁 **strings**
           - 📄 [AhoCorasickTest](src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
           - 📄 [AlphabeticalTest](src/test/java/com/thealgorithms/strings/AlphabeticalTest.java)

From 8a339ef2e2ad0ec7bc3fb9ce8076fc33a61d548e Mon Sep 17 00:00:00 2001
From: Krishna <satyasaikrishnareddy41@gmail.com>
Date: Sat, 15 Nov 2025 14:52:36 +0530
Subject: [PATCH 1098/1338] Add Temperature Conversion Utility (#7066)

- Implements conversions between Celsius, Fahrenheit, and Kelvin
- Includes all 6 conversion methods
- Adds comprehensive unit tests with edge cases
- Fixes #6936
---
 .../conversions/TemperatureConverter.java     | 46 ++++++++++++++++
 .../conversions/TemperatureConverterTest.java | 54 +++++++++++++++++++
 2 files changed, 100 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/conversions/TemperatureConverter.java
 create mode 100644 src/test/java/com/thealgorithms/conversions/TemperatureConverterTest.java

diff --git a/src/main/java/com/thealgorithms/conversions/TemperatureConverter.java b/src/main/java/com/thealgorithms/conversions/TemperatureConverter.java
new file mode 100644
index 000000000000..901db17c665d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/conversions/TemperatureConverter.java
@@ -0,0 +1,46 @@
+package com.thealgorithms.conversions;
+
+/**
+ * A utility class to convert between different temperature units.
+ *
+ * <p>This class supports conversions between the following units:
+ * <ul>
+ *   <li>Celsius</li>
+ *   <li>Fahrenheit</li>
+ *   <li>Kelvin</li>
+ * </ul>
+ *
+ * <p>This class is final and cannot be instantiated.
+ *
+ * @author krishna-medapati (https://github.com/krishna-medapati)
+ * @see <a href="https://en.wikipedia.org/wiki/Conversion_of_scales_of_temperature">Wikipedia: Temperature Conversion</a>
+ */
+public final class TemperatureConverter {
+
+    private TemperatureConverter() {
+    }
+
+    public static double celsiusToFahrenheit(double celsius) {
+        return celsius * 9.0 / 5.0 + 32.0;
+    }
+
+    public static double celsiusToKelvin(double celsius) {
+        return celsius + 273.15;
+    }
+
+    public static double fahrenheitToCelsius(double fahrenheit) {
+        return (fahrenheit - 32.0) * 5.0 / 9.0;
+    }
+
+    public static double fahrenheitToKelvin(double fahrenheit) {
+        return (fahrenheit - 32.0) * 5.0 / 9.0 + 273.15;
+    }
+
+    public static double kelvinToCelsius(double kelvin) {
+        return kelvin - 273.15;
+    }
+
+    public static double kelvinToFahrenheit(double kelvin) {
+        return (kelvin - 273.15) * 9.0 / 5.0 + 32.0;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/conversions/TemperatureConverterTest.java b/src/test/java/com/thealgorithms/conversions/TemperatureConverterTest.java
new file mode 100644
index 000000000000..24d55b706f36
--- /dev/null
+++ b/src/test/java/com/thealgorithms/conversions/TemperatureConverterTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class TemperatureConverterTest {
+
+    private static final double DELTA = 0.01;
+
+    @Test
+    void testCelsiusToFahrenheit() {
+        assertEquals(32.0, TemperatureConverter.celsiusToFahrenheit(0.0), DELTA);
+        assertEquals(212.0, TemperatureConverter.celsiusToFahrenheit(100.0), DELTA);
+        assertEquals(-40.0, TemperatureConverter.celsiusToFahrenheit(-40.0), DELTA);
+        assertEquals(98.6, TemperatureConverter.celsiusToFahrenheit(37.0), DELTA);
+    }
+
+    @Test
+    void testCelsiusToKelvin() {
+        assertEquals(273.15, TemperatureConverter.celsiusToKelvin(0.0), DELTA);
+        assertEquals(373.15, TemperatureConverter.celsiusToKelvin(100.0), DELTA);
+        assertEquals(233.15, TemperatureConverter.celsiusToKelvin(-40.0), DELTA);
+    }
+
+    @Test
+    void testFahrenheitToCelsius() {
+        assertEquals(0.0, TemperatureConverter.fahrenheitToCelsius(32.0), DELTA);
+        assertEquals(100.0, TemperatureConverter.fahrenheitToCelsius(212.0), DELTA);
+        assertEquals(-40.0, TemperatureConverter.fahrenheitToCelsius(-40.0), DELTA);
+        assertEquals(37.0, TemperatureConverter.fahrenheitToCelsius(98.6), DELTA);
+    }
+
+    @Test
+    void testFahrenheitToKelvin() {
+        assertEquals(273.15, TemperatureConverter.fahrenheitToKelvin(32.0), DELTA);
+        assertEquals(373.15, TemperatureConverter.fahrenheitToKelvin(212.0), DELTA);
+        assertEquals(233.15, TemperatureConverter.fahrenheitToKelvin(-40.0), DELTA);
+    }
+
+    @Test
+    void testKelvinToCelsius() {
+        assertEquals(0.0, TemperatureConverter.kelvinToCelsius(273.15), DELTA);
+        assertEquals(100.0, TemperatureConverter.kelvinToCelsius(373.15), DELTA);
+        assertEquals(-273.15, TemperatureConverter.kelvinToCelsius(0.0), DELTA);
+    }
+
+    @Test
+    void testKelvinToFahrenheit() {
+        assertEquals(32.0, TemperatureConverter.kelvinToFahrenheit(273.15), DELTA);
+        assertEquals(212.0, TemperatureConverter.kelvinToFahrenheit(373.15), DELTA);
+        assertEquals(-40.0, TemperatureConverter.kelvinToFahrenheit(233.15), DELTA);
+    }
+}

From 98eecb9f16003e612ad8d84ed6f3c78ae10c7005 Mon Sep 17 00:00:00 2001
From: Taranjeet Singh Kalsi <taranjeetkalsi15@gmail.com>
Date: Sat, 15 Nov 2025 15:02:06 +0530
Subject: [PATCH 1099/1338] Added program to check Smith number (#6955)

added smith number program
---
 .../com/thealgorithms/maths/SmithNumber.java  | 52 +++++++++++++++++++
 .../thealgorithms/maths/SmithNumberTest.java  | 22 ++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/SmithNumber.java
 create mode 100644 src/test/java/com/thealgorithms/maths/SmithNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/SmithNumber.java b/src/main/java/com/thealgorithms/maths/SmithNumber.java
new file mode 100644
index 000000000000..c06e0023d9bb
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/SmithNumber.java
@@ -0,0 +1,52 @@
+package com.thealgorithms.maths;
+
+import com.thealgorithms.maths.Prime.PrimeCheck;
+
+/**
+ * In number theory, a smith number  is a composite number for which, in a given number base,
+ *  the sum of its digits is equal to the sum of the digits in its prime factorization in the same base.
+ *
+ * For example, in base 10, 378 = 21 X 33 X 71 is a Smith number since 3 + 7 + 8 = 2 X 1 + 3 X 3 + 7 X 1,
+ * and 22 = 21 X 111 is a Smith number, because 2 + 2 = 2 X 1 + (1 + 1) X 1.
+ *
+ * Wiki: https://en.wikipedia.org/wiki/Smith_number
+ */
+public final class SmithNumber {
+
+    private SmithNumber() {
+    }
+
+    private static int primeFactorDigitSum(int n) {
+        int sum = 0;
+        int num = n;
+
+        // Factorize the number using trial division
+        for (int i = 2; i * i <= num; i++) {
+            while (n % i == 0) { // while i divides n
+                sum += SumOfDigits.sumOfDigits(i); // add sum of digits of factor
+                n /= i; // divide n by the factor
+            }
+        }
+
+        // If n is still > 1, it itself is a prime factor
+        if (n > 1) {
+            sum += SumOfDigits.sumOfDigits(n);
+        }
+
+        return sum;
+    }
+
+    /**
+     * Check if {@code number} is Smith number or not
+     *
+     * @param number the number
+     * @return {@code true} if {@code number} is a Smith number, otherwise false
+     */
+    public static boolean isSmithNumber(int number) {
+        if (PrimeCheck.isPrime(number)) {
+            return false; // Smith numbers must be composite
+        }
+
+        return SumOfDigits.sumOfDigits(number) == primeFactorDigitSum(number);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/SmithNumberTest.java b/src/test/java/com/thealgorithms/maths/SmithNumberTest.java
new file mode 100644
index 000000000000..4e2ba0b88e33
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/SmithNumberTest.java
@@ -0,0 +1,22 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class SmithNumberTest {
+
+    @ParameterizedTest
+    @CsvSource({"4", "22", "121", "562", "985", "4937775"})
+    void positiveSmithNumbersTest(int n) {
+        assertTrue(SmithNumber.isSmithNumber(n));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"2", "11", "100", "550", "999", "1234557"})
+    void negativeSmithNumbersTest(int n) {
+        assertFalse(SmithNumber.isSmithNumber(n));
+    }
+}

From 3979e824b7683c5435df1b8d703433123da9a31c Mon Sep 17 00:00:00 2001
From: Krishna <satyasaikrishnareddy41@gmail.com>
Date: Sat, 15 Nov 2025 23:06:01 +0530
Subject: [PATCH 1100/1338] Add Power of Four Check using bit manipulation
 (#7065)

* Add Power of Four Check using bit manipulation

- Implements isPowerOfFour method using bit manipulation
- Checks if number is power of two and has bit at even position
- Includes comprehensive unit tests
- Fixes #6940

* Fix code formatting in PowerOfFourTest

* Move PowerOfFour classes to maths package

* Fix package declaration in PowerOfFourTest

* Fix code formatting in PowerOfFourTest

* Remove redundant import from PowerOfFourTest

* Remove unrelated file
---
 .../com/thealgorithms/maths/PowerOfFour.java  | 36 +++++++++++++++++++
 .../thealgorithms/maths/PowerOfFourTest.java  | 36 +++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/PowerOfFour.java
 create mode 100644 src/test/java/com/thealgorithms/maths/PowerOfFourTest.java

diff --git a/src/main/java/com/thealgorithms/maths/PowerOfFour.java b/src/main/java/com/thealgorithms/maths/PowerOfFour.java
new file mode 100644
index 000000000000..e5fe6255821b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/PowerOfFour.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.maths;
+
+/**
+ * Utility class for checking if a number is a power of four.
+ * A power of four is a number that can be expressed as 4^n where n is a non-negative integer.
+ * This class provides a method to determine if a given integer is a power of four using bit manipulation.
+ *
+ * @author krishna-medapati (https://github.com/krishna-medapati)
+ */
+public final class PowerOfFour {
+    private PowerOfFour() {
+    }
+
+    /**
+     * Checks if the given integer is a power of four.
+     *
+     * A number is considered a power of four if:
+     * 1. It is greater than zero
+     * 2. It has exactly one '1' bit in its binary representation (power of two)
+     * 3. The '1' bit is at an even position (0, 2, 4, 6, ...)
+     *
+     * The method uses the mask 0x55555555 (binary: 01010101010101010101010101010101)
+     * to check if the set bit is at an even position.
+     *
+     * @param number the integer to check
+     * @return true if the number is a power of four, false otherwise
+     */
+    public static boolean isPowerOfFour(int number) {
+        if (number <= 0) {
+            return false;
+        }
+        boolean isPowerOfTwo = (number & (number - 1)) == 0;
+        boolean hasEvenBitPosition = (number & 0x55555555) != 0;
+        return isPowerOfTwo && hasEvenBitPosition;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/PowerOfFourTest.java b/src/test/java/com/thealgorithms/maths/PowerOfFourTest.java
new file mode 100644
index 000000000000..c91f8b3cf1b5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/PowerOfFourTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class PowerOfFourTest {
+
+    @Test
+    void testPowersOfFour() {
+        assertTrue(PowerOfFour.isPowerOfFour(1));
+        assertTrue(PowerOfFour.isPowerOfFour(4));
+        assertTrue(PowerOfFour.isPowerOfFour(16));
+        assertTrue(PowerOfFour.isPowerOfFour(64));
+        assertTrue(PowerOfFour.isPowerOfFour(256));
+        assertTrue(PowerOfFour.isPowerOfFour(1024));
+    }
+
+    @Test
+    void testNonPowersOfFour() {
+        assertFalse(PowerOfFour.isPowerOfFour(2));
+        assertFalse(PowerOfFour.isPowerOfFour(3));
+        assertFalse(PowerOfFour.isPowerOfFour(5));
+        assertFalse(PowerOfFour.isPowerOfFour(8));
+        assertFalse(PowerOfFour.isPowerOfFour(15));
+        assertFalse(PowerOfFour.isPowerOfFour(32));
+    }
+
+    @Test
+    void testEdgeCases() {
+        assertFalse(PowerOfFour.isPowerOfFour(0));
+        assertFalse(PowerOfFour.isPowerOfFour(-1));
+        assertFalse(PowerOfFour.isPowerOfFour(-4));
+    }
+}

From 93811614b868b2d8f4e1aaa3f4918982036684ff Mon Sep 17 00:00:00 2001
From: GOPISETTI NAVADEEP <2400030007@kluniversity.in>
Date: Sun, 16 Nov 2025 17:24:43 +0530
Subject: [PATCH 1101/1338] feat: add Count Set Bits algorithm (#7072)

* feat: add Count Set Bits algorithm (issue #6931)

* fix: correct CountSetBits algorithm logic

* style: apply clang-format to CountSetBits files

* fix: correct test expectations for CountSetBits

* fix: correct test expectations for CountSetBits
---
 .../bitmanipulation/CountSetBits.java         | 114 +++++++++---------
 .../bitmanipulation/CountSetBitsTest.java     |  56 +++++++--
 2 files changed, 100 insertions(+), 70 deletions(-)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java b/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java
index 242f35fc35f2..7df522ca8f69 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java
@@ -1,79 +1,79 @@
 package com.thealgorithms.bitmanipulation;
 
-public class CountSetBits {
+/**
+ * Utility class to count total set bits from 1 to N
+ * A set bit is a bit in binary representation that is 1
+ *
+ * @author navadeep
+ */
+public final class CountSetBits {
+
+    private CountSetBits() {
+        // Utility class, prevent instantiation
+    }
 
     /**
-     * The below algorithm is called as Brian Kernighan's algorithm
-     * We can use Brian Kernighan’s algorithm to improve the above naive algorithm’s performance.
-     The idea is to only consider the set bits of an integer by turning off its rightmost set bit
-     (after counting it), so the next iteration of the loop considers the next rightmost bit.
-
-        The expression n & (n-1) can be used to turn off the rightmost set bit of a number n. This
-     works as the expression n-1 flips all the bits after the rightmost set bit of n, including the
-     rightmost set bit itself. Therefore, n & (n-1) results in the last bit flipped of n.
-
-        For example, consider number 52, which is 00110100 in binary, and has a total 3 bits set.
-
-        1st iteration of the loop: n = 52
-
-        00110100    &               (n)
-        00110011                    (n-1)
-        ~~~~~~~~
-        00110000
+     * Counts total number of set bits in all numbers from 1 to n
+     * Time Complexity: O(log n)
+     *
+     * @param n the upper limit (inclusive)
+     * @return total count of set bits from 1 to n
+     * @throws IllegalArgumentException if n is negative
+     */
+    public static int countSetBits(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input must be non-negative");
+        }
 
+        if (n == 0) {
+            return 0;
+        }
 
-        2nd iteration of the loop: n = 48
+        // Find the largest power of 2 <= n
+        int x = largestPowerOf2InNumber(n);
 
-        00110000    &               (n)
-        00101111                    (n-1)
-        ~~~~~~~~
-        00100000
+        // Total bits at position x: x * 2^(x-1)
+        int bitsAtPositionX = x * (1 << (x - 1));
 
+        // Remaining numbers after 2^x
+        int remainingNumbers = n - (1 << x) + 1;
 
-        3rd iteration of the loop: n = 32
+        // Recursively count for the rest
+        int rest = countSetBits(n - (1 << x));
 
-        00100000    &               (n)
-        00011111                    (n-1)
-        ~~~~~~~~
-        00000000                    (n = 0)
+        return bitsAtPositionX + remainingNumbers + rest;
+    }
 
-     * @param num takes Long number whose number of set bit is to be found
-     * @return the count of set bits in the binary equivalent
-    */
-    public long countSetBits(long num) {
-        long cnt = 0;
-        while (num > 0) {
-            cnt++;
-            num &= (num - 1);
+    /**
+     * Finds the position of the most significant bit in n
+     *
+     * @param n the number
+     * @return position of MSB (0-indexed from right)
+     */
+    private static int largestPowerOf2InNumber(int n) {
+        int position = 0;
+        while ((1 << position) <= n) {
+            position++;
         }
-        return cnt;
+        return position - 1;
     }
 
     /**
-     * This approach takes O(1) running time to count the set bits, but requires a pre-processing.
+     * Alternative naive approach - counts set bits by iterating through all numbers
+     * Time Complexity: O(n log n)
      *
-     * So, we divide our 32-bit input into 8-bit chunks, with four chunks. We have 8 bits in each chunk.
-     *
-     * Then the range is from 0-255 (0 to 2^7).
-     * So, we may need to count set bits from 0 to 255 in individual chunks.
-     *
-     * @param num takes a long number
-     * @return the count of set bits in the binary equivalent
+     * @param n the upper limit (inclusive)
+     * @return total count of set bits from 1 to n
      */
-    public int lookupApproach(int num) {
-        int[] table = new int[256];
-        table[0] = 0;
-
-        for (int i = 1; i < 256; i++) {
-            table[i] = (i & 1) + table[i >> 1]; // i >> 1 equals to i/2
+    public static int countSetBitsNaive(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input must be non-negative");
         }
 
-        int res = 0;
-        for (int i = 0; i < 4; i++) {
-            res += table[num & 0xff];
-            num >>= 8;
+        int count = 0;
+        for (int i = 1; i <= n; i++) {
+            count += Integer.bitCount(i);
         }
-
-        return res;
+        return count;
     }
 }
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java b/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java
index 61e0757f9c12..757c6edc0151 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java
@@ -1,26 +1,56 @@
 package com.thealgorithms.bitmanipulation;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
-public class CountSetBitsTest {
+class CountSetBitsTest {
 
     @Test
-    void testSetBits() {
-        CountSetBits csb = new CountSetBits();
-        assertEquals(1L, csb.countSetBits(16));
-        assertEquals(4, csb.countSetBits(15));
-        assertEquals(5, csb.countSetBits(10000));
-        assertEquals(5, csb.countSetBits(31));
+    void testCountSetBitsZero() {
+        assertEquals(0, CountSetBits.countSetBits(0));
     }
 
     @Test
-    void testSetBitsLookupApproach() {
-        CountSetBits csb = new CountSetBits();
-        assertEquals(1L, csb.lookupApproach(16));
-        assertEquals(4, csb.lookupApproach(15));
-        assertEquals(5, csb.lookupApproach(10000));
-        assertEquals(5, csb.lookupApproach(31));
+    void testCountSetBitsOne() {
+        assertEquals(1, CountSetBits.countSetBits(1));
+    }
+
+    @Test
+    void testCountSetBitsSmallNumber() {
+        assertEquals(4, CountSetBits.countSetBits(3)); // 1(1) + 10(1) + 11(2) = 4
+    }
+
+    @Test
+    void testCountSetBitsFive() {
+        assertEquals(7, CountSetBits.countSetBits(5)); // 1 + 1 + 2 + 1 + 2 = 7
+    }
+
+    @Test
+    void testCountSetBitsTen() {
+        assertEquals(17, CountSetBits.countSetBits(10));
+    }
+
+    @Test
+    void testCountSetBitsLargeNumber() {
+        assertEquals(42, CountSetBits.countSetBits(20)); // Changed from 93 to 42
+    }
+
+    @Test
+    void testCountSetBitsPowerOfTwo() {
+        assertEquals(13, CountSetBits.countSetBits(8)); // Changed from 9 to 13
+    }
+
+    @Test
+    void testCountSetBitsNegativeInput() {
+        assertThrows(IllegalArgumentException.class, () -> CountSetBits.countSetBits(-1));
+    }
+
+    @Test
+    void testNaiveApproachMatchesOptimized() {
+        for (int i = 0; i <= 100; i++) {
+            assertEquals(CountSetBits.countSetBitsNaive(i), CountSetBits.countSetBits(i), "Mismatch at n = " + i);
+        }
     }
 }

From c6880c195d778b1d19fc13d4be1ae09dc355de2f Mon Sep 17 00:00:00 2001
From: GOPISETTI NAVADEEP <2400030007@kluniversity.in>
Date: Sun, 16 Nov 2025 17:30:21 +0530
Subject: [PATCH 1102/1338] feat: add Sieve of Eratosthenes algorithm (#7071)

* feat: add Sieve of Eratosthenes algorithm

- Implement Sieve of Eratosthenes for finding prime numbers up to n
- Add comprehensive unit tests with edge cases
- Include JavaDoc documentation
- Time complexity: O(n log log n)
- Space complexity: O(n)

Resolves #6939

* fix: remove trailing spaces

* fix: apply clang-format
---
 .../maths/SieveOfEratosthenes.java            | 98 +++++++++++--------
 .../maths/SieveOfEratosthenesTest.java        | 60 ++++++++----
 2 files changed, 96 insertions(+), 62 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java b/src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java
index f22d22e8c6af..5a15c4201a15 100644
--- a/src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java
+++ b/src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java
@@ -1,66 +1,82 @@
 package com.thealgorithms.maths;
 
-import java.util.Arrays;
+import java.util.ArrayList;
+import java.util.List;
 
 /**
- * @brief utility class implementing <a href="https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes">Sieve of Eratosthenes</a>
+ * Sieve of Eratosthenes Algorithm
+ * An efficient algorithm to find all prime numbers up to a given limit.
+ *
+ * Algorithm:
+ * 1. Create a boolean array of size n+1, initially all true
+ * 2. Mark 0 and 1 as not prime
+ * 3. For each number i from 2 to sqrt(n):
+ *    - If i is still marked as prime
+ *    - Mark all multiples of i (starting from i²) as not prime
+ * 4. Collect all numbers still marked as prime
+ *
+ * Time Complexity: O(n log log n)
+ * Space Complexity: O(n)
+ *
+ * @author Navadeep0007
+ * @see <a href="https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes">Sieve of Eratosthenes</a>
  */
 public final class SieveOfEratosthenes {
+
     private SieveOfEratosthenes() {
+        // Utility class, prevent instantiation
     }
 
-    private static void checkInput(int n) {
-        if (n <= 0) {
-            throw new IllegalArgumentException("n must be positive.");
+    /**
+     * Finds all prime numbers up to n using the Sieve of Eratosthenes algorithm
+     *
+     * @param n the upper limit (inclusive)
+     * @return a list of all prime numbers from 2 to n
+     * @throws IllegalArgumentException if n is negative
+     */
+    public static List<Integer> findPrimes(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input must be non-negative");
         }
-    }
 
-    private static Type[] sievePrimesTill(int n) {
-        checkInput(n);
-        Type[] isPrimeArray = new Type[n + 1];
-        Arrays.fill(isPrimeArray, Type.PRIME);
-        isPrimeArray[0] = Type.NOT_PRIME;
-        isPrimeArray[1] = Type.NOT_PRIME;
+        if (n < 2) {
+            return new ArrayList<>();
+        }
+
+        // Create boolean array, initially all true
+        boolean[] isPrime = new boolean[n + 1];
+        for (int i = 2; i <= n; i++) {
+            isPrime[i] = true;
+        }
 
-        double cap = Math.sqrt(n);
-        for (int i = 2; i <= cap; i++) {
-            if (isPrimeArray[i] == Type.PRIME) {
-                for (int j = 2; i * j <= n; j++) {
-                    isPrimeArray[i * j] = Type.NOT_PRIME;
+        // Sieve process
+        for (int i = 2; i * i <= n; i++) {
+            if (isPrime[i]) {
+                // Mark all multiples of i as not prime
+                for (int j = i * i; j <= n; j += i) {
+                    isPrime[j] = false;
                 }
             }
         }
-        return isPrimeArray;
-    }
-
-    private static int countPrimes(Type[] isPrimeArray) {
-        return (int) Arrays.stream(isPrimeArray).filter(element -> element == Type.PRIME).count();
-    }
 
-    private static int[] extractPrimes(Type[] isPrimeArray) {
-        int numberOfPrimes = countPrimes(isPrimeArray);
-        int[] primes = new int[numberOfPrimes];
-        int primeIndex = 0;
-        for (int curNumber = 0; curNumber < isPrimeArray.length; ++curNumber) {
-            if (isPrimeArray[curNumber] == Type.PRIME) {
-                primes[primeIndex++] = curNumber;
+        // Collect all prime numbers
+        List<Integer> primes = new ArrayList<>();
+        for (int i = 2; i <= n; i++) {
+            if (isPrime[i]) {
+                primes.add(i);
             }
         }
+
         return primes;
     }
 
     /**
-     * @brief finds all of the prime numbers up to the given upper (inclusive) limit
-     * @param n upper (inclusive) limit
-     * @exception IllegalArgumentException n is non-positive
-     * @return the array of all primes up to the given number (inclusive)
+     * Counts the number of prime numbers up to n
+     *
+     * @param n the upper limit (inclusive)
+     * @return count of prime numbers from 2 to n
      */
-    public static int[] findPrimesTill(int n) {
-        return extractPrimes(sievePrimesTill(n));
-    }
-
-    private enum Type {
-        PRIME,
-        NOT_PRIME,
+    public static int countPrimes(int n) {
+        return findPrimes(n).size();
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java b/src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java
index ebbd5df712fc..5d491a493ee7 100644
--- a/src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java
+++ b/src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java
@@ -1,46 +1,64 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.util.Arrays;
+import java.util.List;
 import org.junit.jupiter.api.Test;
 
+/**
+ * Test cases for Sieve of Eratosthenes algorithm
+ *
+ * @author Navadeep0007
+ */
 class SieveOfEratosthenesTest {
+
+    @Test
+    void testPrimesUpTo10() {
+        List<Integer> expected = Arrays.asList(2, 3, 5, 7);
+        assertEquals(expected, SieveOfEratosthenes.findPrimes(10));
+    }
+
+    @Test
+    void testPrimesUpTo30() {
+        List<Integer> expected = Arrays.asList(2, 3, 5, 7, 11, 13, 17, 19, 23, 29);
+        assertEquals(expected, SieveOfEratosthenes.findPrimes(30));
+    }
+
     @Test
-    public void testfFindPrimesTill1() {
-        assertArrayEquals(new int[] {}, SieveOfEratosthenes.findPrimesTill(1));
+    void testPrimesUpTo2() {
+        List<Integer> expected = Arrays.asList(2);
+        assertEquals(expected, SieveOfEratosthenes.findPrimes(2));
     }
 
     @Test
-    public void testfFindPrimesTill2() {
-        assertArrayEquals(new int[] {2}, SieveOfEratosthenes.findPrimesTill(2));
+    void testPrimesUpTo1() {
+        assertTrue(SieveOfEratosthenes.findPrimes(1).isEmpty());
     }
 
     @Test
-    public void testfFindPrimesTill4() {
-        var primesTill4 = new int[] {2, 3};
-        assertArrayEquals(primesTill4, SieveOfEratosthenes.findPrimesTill(3));
-        assertArrayEquals(primesTill4, SieveOfEratosthenes.findPrimesTill(4));
+    void testPrimesUpTo0() {
+        assertTrue(SieveOfEratosthenes.findPrimes(0).isEmpty());
     }
 
     @Test
-    public void testfFindPrimesTill40() {
-        var primesTill40 = new int[] {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37};
-        assertArrayEquals(primesTill40, SieveOfEratosthenes.findPrimesTill(37));
-        assertArrayEquals(primesTill40, SieveOfEratosthenes.findPrimesTill(38));
-        assertArrayEquals(primesTill40, SieveOfEratosthenes.findPrimesTill(39));
-        assertArrayEquals(primesTill40, SieveOfEratosthenes.findPrimesTill(40));
+    void testNegativeInput() {
+        assertThrows(IllegalArgumentException.class, () -> { SieveOfEratosthenes.findPrimes(-1); });
     }
 
     @Test
-    public void testfFindPrimesTill240() {
-        var primesTill240 = new int[] {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239};
-        assertArrayEquals(primesTill240, SieveOfEratosthenes.findPrimesTill(239));
-        assertArrayEquals(primesTill240, SieveOfEratosthenes.findPrimesTill(240));
+    void testCountPrimes() {
+        assertEquals(4, SieveOfEratosthenes.countPrimes(10));
+        assertEquals(25, SieveOfEratosthenes.countPrimes(100));
     }
 
     @Test
-    public void testFindPrimesTillThrowsExceptionForNonPositiveInput() {
-        assertThrows(IllegalArgumentException.class, () -> SieveOfEratosthenes.findPrimesTill(0));
+    void testLargeNumber() {
+        List<Integer> primes = SieveOfEratosthenes.findPrimes(1000);
+        assertEquals(168, primes.size()); // There are 168 primes up to 1000
+        assertEquals(2, primes.get(0)); // First prime
+        assertEquals(997, primes.get(primes.size() - 1)); // Last prime up to 1000
     }
 }

From cff5d3662e5446ff3371adcb5278ccb2085c956f Mon Sep 17 00:00:00 2001
From: SeungHyeok Yun <162292720+SeungHyeokYoon@users.noreply.github.com>
Date: Mon, 17 Nov 2025 03:49:30 +0900
Subject: [PATCH 1103/1338] feat: add IndexedPriorityQueue implementation and
 tests (#7062)

* feat: add IndexedPriorityQueue implementation and tests

* mod : clang-format

* Fix Checkstyle naming for IndexedPriorityQueue tests

* Align IndexedPriorityQueue tests with Checkstyle and clang-format
---
 .../heaps/IndexedPriorityQueue.java           | 327 ++++++++++++++++
 .../heaps/IndexedPriorityQueueTest.java       | 350 ++++++++++++++++++
 2 files changed, 677 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/heaps/IndexedPriorityQueue.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/heaps/IndexedPriorityQueueTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/heaps/IndexedPriorityQueue.java b/src/main/java/com/thealgorithms/datastructures/heaps/IndexedPriorityQueue.java
new file mode 100644
index 000000000000..ad7229760fd0
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/heaps/IndexedPriorityQueue.java
@@ -0,0 +1,327 @@
+package com.thealgorithms.datastructures.heaps;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.IdentityHashMap;
+import java.util.Objects;
+import java.util.function.Consumer;
+
+/**
+ * An addressable (indexed) min-priority queue with O(log n) updates.
+ *
+ * <p>Key features:
+ * <ul>
+ *   <li>Each element E is tracked by a handle (its current heap index) via a map,
+ *       enabling O(log n) {@code remove(e)} and O(log n) key updates
+ *       ({@code changeKey/decreaseKey/increaseKey}).</li>
+ *   <li>The queue order is determined by the provided {@link Comparator}. If the
+ *       comparator is {@code null}, elements must implement {@link Comparable}
+ *       (same contract as {@link java.util.PriorityQueue}).</li>
+ *   <li>By default this implementation uses {@link IdentityHashMap} for the index
+ *       mapping to avoid issues with duplicate-equals elements or mutable equals/hashCode.
+ *       If you need value-based equality, switch to {@code HashMap} and read the caveats
+ *       in the class-level Javadoc carefully.</li>
+ * </ul>
+ *
+ * <h2>IMPORTANT contracts</h2>
+ * <ul>
+ *   <li><b>Do not mutate comparator-relevant fields of an element directly</b> while it is
+ *       inside the queue. Always use {@code changeKey}/{@code decreaseKey}/{@code increaseKey}
+ *       so the heap can be restored accordingly.</li>
+ *   <li>If you replace {@link IdentityHashMap} with {@link HashMap}, you must ensure:
+ *       (a) no two distinct elements are {@code equals()}-equal at the same time in the queue, and
+ *       (b) {@code equals/hashCode} of elements remain stable while enqueued.</li>
+ *   <li>{@code peek()} returns {@code null} when empty (matching {@link java.util.PriorityQueue}).</li>
+ *   <li>Not thread-safe.</li>
+ * </ul>
+ *
+ * <p>Complexities:
+ * {@code offer, poll, remove(e), changeKey, decreaseKey, increaseKey} are O(log n);
+ * {@code peek, isEmpty, size, contains} are O(1).
+ */
+public class IndexedPriorityQueue<E> {
+
+    /** Binary heap storage (min-heap). */
+    private Object[] heap;
+
+    /** Number of elements in the heap. */
+    private int size;
+
+    /** Comparator used for ordering; if null, elements must be Comparable. */
+    private final Comparator<? super E> cmp;
+
+    /**
+     * Index map: element -> current heap index.
+     * <p>We use IdentityHashMap by default to:
+     * <ul>
+     *   <li>allow duplicate-equals elements;</li>
+     *   <li>avoid corruption when equals/hashCode are mutable or not ID-based.</li>
+     * </ul>
+     * If you prefer value-based semantics, replace with HashMap<E,Integer> and
+     * respect the warnings in the class Javadoc.
+     */
+    private final IdentityHashMap<E, Integer> index;
+
+    private static final int DEFAULT_INITIAL_CAPACITY = 11;
+
+    public IndexedPriorityQueue() {
+        this(DEFAULT_INITIAL_CAPACITY, null);
+    }
+
+    public IndexedPriorityQueue(Comparator<? super E> cmp) {
+        this(DEFAULT_INITIAL_CAPACITY, cmp);
+    }
+
+    public IndexedPriorityQueue(int initialCapacity, Comparator<? super E> cmp) {
+        if (initialCapacity < 1) {
+            throw new IllegalArgumentException("initialCapacity < 1");
+        }
+        this.heap = new Object[initialCapacity];
+        this.cmp = cmp;
+        this.index = new IdentityHashMap<>();
+    }
+
+    /** Returns current number of elements. */
+    public int size() {
+        return size;
+    }
+
+    /** Returns {@code true} if empty. */
+    public boolean isEmpty() {
+        return size == 0;
+    }
+
+    /**
+     * Returns the minimum element without removing it, or {@code null} if empty.
+     * Matches {@link java.util.PriorityQueue#peek()} behavior.
+     */
+    @SuppressWarnings("unchecked")
+    public E peek() {
+        return size == 0 ? null : (E) heap[0];
+    }
+
+    /**
+     * Inserts the specified element (O(log n)).
+     * @throws NullPointerException if {@code e} is null
+     * @throws ClassCastException if {@code cmp == null} and {@code e} is not Comparable,
+     *                            or if incompatible with other elements
+     */
+    public boolean offer(E e) {
+        Objects.requireNonNull(e, "element is null");
+        if (size >= heap.length) {
+            grow(size + 1);
+        }
+        // Insert at the end and bubble up. siftUp will maintain 'index' for all touched nodes.
+        siftUp(size, e);
+        size++;
+        return true;
+    }
+
+    /**
+     * Removes and returns the minimum element (O(log n)), or {@code null} if empty.
+     */
+    @SuppressWarnings("unchecked")
+    public E poll() {
+        if (size == 0) {
+            return null;
+        }
+        E min = (E) heap[0];
+        removeAt(0); // updates map and heap structure
+        return min;
+    }
+
+    /**
+     * Removes one occurrence of the specified element e (O(log n)) if present.
+     * Uses the index map for O(1) lookup.
+     */
+    public boolean remove(Object o) {
+        Integer i = index.get(o);
+        if (i == null) {
+            return false;
+        }
+        removeAt(i);
+        return true;
+    }
+
+    /** O(1): returns whether the queue currently contains the given element reference. */
+    public boolean contains(Object o) {
+        return index.containsKey(o);
+    }
+
+    /** Clears the heap and the index map. */
+    public void clear() {
+        Arrays.fill(heap, 0, size, null);
+        index.clear();
+        size = 0;
+    }
+
+    // ------------------------------------------------------------------------------------
+    // Key update API
+    // ------------------------------------------------------------------------------------
+
+    /**
+     * Changes comparator-relevant fields of {@code e} via the provided {@code mutator},
+     * then restores the heap in O(log n) by bubbling in the correct direction.
+     *
+     * <p><b>IMPORTANT:</b> The mutator must not change {@code equals/hashCode} of {@code e}
+     * if you migrate this implementation to value-based indexing (HashMap).
+     *
+     * @throws IllegalArgumentException if {@code e} is not in the queue
+     */
+    public void changeKey(E e, Consumer<E> mutator) {
+        Integer i = index.get(e);
+        if (i == null) {
+            throw new IllegalArgumentException("Element not in queue");
+        }
+        // Mutate fields used by comparator (do NOT mutate equality/hash if using value-based map)
+        mutator.accept(e);
+        // Try bubbling up; if no movement occurred, bubble down.
+        if (!siftUp(i)) {
+            siftDown(i);
+        }
+    }
+
+    /**
+     * Faster variant if the new key is strictly smaller (higher priority).
+     * Performs a single sift-up (O(log n)).
+     */
+    public void decreaseKey(E e, Consumer<E> mutator) {
+        Integer i = index.get(e);
+        if (i == null) {
+            throw new IllegalArgumentException("Element not in queue");
+        }
+        mutator.accept(e);
+        siftUp(i);
+    }
+
+    /**
+     * Faster variant if the new key is strictly larger (lower priority).
+     * Performs a single sift-down (O(log n)).
+     */
+    public void increaseKey(E e, Consumer<E> mutator) {
+        Integer i = index.get(e);
+        if (i == null) {
+            throw new IllegalArgumentException("Element not in queue");
+        }
+        mutator.accept(e);
+        siftDown(i);
+    }
+
+    // ------------------------------------------------------------------------------------
+    // Internal utilities
+    // ------------------------------------------------------------------------------------
+
+    /** Grows the internal array to accommodate at least {@code minCapacity}. */
+    private void grow(int minCapacity) {
+        int old = heap.length;
+        int pref = (old < 64) ? old + 2 : old + (old >> 1); // +2 if small, else +50%
+        int newCap = Math.max(minCapacity, pref);
+        heap = Arrays.copyOf(heap, newCap);
+    }
+
+    @SuppressWarnings("unchecked")
+    private int compare(E a, E b) {
+        if (cmp != null) {
+            return cmp.compare(a, b);
+        }
+        return ((Comparable<? super E>) a).compareTo(b);
+    }
+
+    /**
+     * Inserts item {@code x} at position {@code k}, bubbling up while maintaining the heap.
+     * Also maintains the index map for all moved elements.
+     */
+    @SuppressWarnings("unchecked")
+    private void siftUp(int k, E x) {
+        while (k > 0) {
+            int p = (k - 1) >>> 1;
+            E e = (E) heap[p];
+            if (compare(x, e) >= 0) {
+                break;
+            }
+            heap[k] = e;
+            index.put(e, k);
+            k = p;
+        }
+        heap[k] = x;
+        index.put(x, k);
+    }
+
+    /**
+     * Attempts to bubble up the element currently at {@code k}.
+     * @return true if it moved; false otherwise.
+     */
+    @SuppressWarnings("unchecked")
+    private boolean siftUp(int k) {
+        int orig = k;
+        E x = (E) heap[k];
+        while (k > 0) {
+            int p = (k - 1) >>> 1;
+            E e = (E) heap[p];
+            if (compare(x, e) >= 0) {
+                break;
+            }
+            heap[k] = e;
+            index.put(e, k);
+            k = p;
+        }
+        if (k != orig) {
+            heap[k] = x;
+            index.put(x, k);
+            return true;
+        }
+        return false;
+    }
+
+    /** Bubbles down the element currently at {@code k}. */
+    @SuppressWarnings("unchecked")
+    private void siftDown(int k) {
+        int n = size;
+        E x = (E) heap[k];
+        int half = n >>> 1; // loop while k has at least one child
+        while (k < half) {
+            int child = (k << 1) + 1; // assume left is smaller
+            E c = (E) heap[child];
+            int r = child + 1;
+            if (r < n && compare(c, (E) heap[r]) > 0) {
+                child = r;
+                c = (E) heap[child];
+            }
+            if (compare(x, c) <= 0) {
+                break;
+            }
+            heap[k] = c;
+            index.put(c, k);
+            k = child;
+        }
+        heap[k] = x;
+        index.put(x, k);
+    }
+
+    /**
+     * Removes the element at heap index {@code i}, restoring the heap afterwards.
+     * <p>Returns nothing; the standard {@code PriorityQueue} returns a displaced
+     * element in a rare case to help its iterator. We don't need that here, so
+     * we keep the API simple.
+     */
+    @SuppressWarnings("unchecked")
+    private void removeAt(int i) {
+        int n = --size; // last index after removal
+        E moved = (E) heap[n];
+        E removed = (E) heap[i];
+        heap[n] = null; // help GC
+        index.remove(removed); // drop mapping for removed element
+
+        if (i == n) {
+            return; // removed last element; done
+        }
+
+        heap[i] = moved;
+        index.put(moved, i);
+
+        // Try sift-up first (cheap if key decreased); if no movement, sift-down.
+        if (!siftUp(i)) {
+            siftDown(i);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/IndexedPriorityQueueTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/IndexedPriorityQueueTest.java
new file mode 100644
index 000000000000..8d8c4e1db6bd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/IndexedPriorityQueueTest.java
@@ -0,0 +1,350 @@
+package com.thealgorithms.datastructures.heaps;
+
+import java.util.Comparator;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests for {@link IndexedPriorityQueue}.
+ *
+ * Notes:
+ * - We mainly use a Node class with a mutable "prio" field to test changeKey/decreaseKey/increaseKey.
+ * - The queue is a min-heap, so smaller "prio" means higher priority.
+ * - By default the implementation uses IdentityHashMap so duplicate-equals objects are allowed.
+ */
+public class IndexedPriorityQueueTest {
+
+    // ------------------------
+    // Helpers
+    // ------------------------
+
+    /** Simple payload with mutable priority. */
+    static class Node {
+        final String id;
+        int prio; // lower is better (min-heap)
+
+        Node(String id, int prio) {
+            this.id = id;
+            this.prio = prio;
+        }
+
+        @Override
+        public String toString() {
+            return id + "(" + prio + ")";
+        }
+    }
+
+    /** Same as Node but overrides equals/hashCode to simulate "duplicate-equals" scenario. */
+    static class NodeWithEquals {
+        final String id;
+        int prio;
+
+        NodeWithEquals(String id, int prio) {
+            this.id = id;
+            this.prio = prio;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (!(o instanceof NodeWithEquals)) {
+                return false;
+            }
+            NodeWithEquals other = (NodeWithEquals) o;
+            // Intentionally naive equality: equal if priority is equal
+            return this.prio == other.prio;
+        }
+
+        @Override
+        public int hashCode() {
+            return Integer.hashCode(prio);
+        }
+
+        @Override
+        public String toString() {
+            return id + "(" + prio + ")";
+        }
+    }
+
+    private static IndexedPriorityQueue<Node> newNodePQ() {
+        return new IndexedPriorityQueue<>(Comparator.comparingInt(n -> n.prio));
+    }
+
+    // ------------------------
+    // Basic operations
+    // ------------------------
+
+    @Test
+    void testOfferPollWithIntegersComparableMode() {
+        // cmp == null -> elements must be Comparable
+        IndexedPriorityQueue<Integer> pq = new IndexedPriorityQueue<>();
+        Assertions.assertTrue(pq.isEmpty());
+
+        pq.offer(5);
+        pq.offer(1);
+        pq.offer(3);
+
+        Assertions.assertEquals(3, pq.size());
+        Assertions.assertEquals(1, pq.peek());
+        Assertions.assertEquals(1, pq.poll());
+        Assertions.assertEquals(3, pq.poll());
+        Assertions.assertEquals(5, pq.poll());
+        Assertions.assertNull(pq.poll()); // empty -> null
+        Assertions.assertTrue(pq.isEmpty());
+    }
+
+    @Test
+    void testPeekAndIsEmpty() {
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Assertions.assertTrue(pq.isEmpty());
+        Assertions.assertNull(pq.peek());
+
+        pq.offer(new Node("A", 10));
+        pq.offer(new Node("B", 5));
+        pq.offer(new Node("C", 7));
+
+        Assertions.assertFalse(pq.isEmpty());
+        Assertions.assertEquals("B(5)", pq.peek().toString());
+    }
+
+    @Test
+    void testRemoveSpecificElement() {
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Node a = new Node("A", 10);
+        Node b = new Node("B", 5);
+        Node c = new Node("C", 7);
+
+        pq.offer(a);
+        pq.offer(b);
+        pq.offer(c);
+
+        // remove by reference (O(log n))
+        Assertions.assertTrue(pq.remove(b));
+        Assertions.assertEquals(2, pq.size());
+        // now min should be C(7)
+        Assertions.assertEquals("C(7)", pq.peek().toString());
+        // removing an element not present -> false
+        Assertions.assertFalse(pq.remove(b));
+    }
+
+    @Test
+    void testContainsAndClear() {
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Node a = new Node("A", 2);
+        Node b = new Node("B", 3);
+
+        pq.offer(a);
+        pq.offer(b);
+
+        Assertions.assertTrue(pq.contains(a));
+        Assertions.assertTrue(pq.contains(b));
+
+        pq.clear();
+        Assertions.assertTrue(pq.isEmpty());
+        Assertions.assertFalse(pq.contains(a));
+        Assertions.assertNull(pq.peek());
+    }
+
+    // ------------------------
+    // Key updates
+    // ------------------------
+
+    @Test
+    void testDecreaseKeyMovesUp() {
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Node a = new Node("A", 10);
+        Node b = new Node("B", 5);
+        Node c = new Node("C", 7);
+
+        pq.offer(a);
+        pq.offer(b);
+        pq.offer(c);
+
+        // current min is B(5)
+        Assertions.assertEquals("B(5)", pq.peek().toString());
+
+        // Make A more important: 10 -> 1 (smaller is better)
+        pq.decreaseKey(a, n -> n.prio = 1);
+
+        // Now A should be at the top
+        Assertions.assertEquals("A(1)", pq.peek().toString());
+    }
+
+    @Test
+    void testIncreaseKeyMovesDown() {
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Node a = new Node("A", 1);
+        Node b = new Node("B", 2);
+        Node c = new Node("C", 3);
+
+        pq.offer(a);
+        pq.offer(b);
+        pq.offer(c);
+
+        // min is A(1)
+        Assertions.assertEquals("A(1)", pq.peek().toString());
+
+        // Make A worse: 1 -> 100
+        pq.increaseKey(a, n -> n.prio = 100);
+
+        // Now min should be B(2)
+        Assertions.assertEquals("B(2)", pq.peek().toString());
+    }
+
+    @Test
+    void testChangeKeyChoosesDirectionAutomatically() {
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Node a = new Node("A", 10);
+        Node b = new Node("B", 20);
+        Node c = new Node("C", 30);
+
+        pq.offer(a);
+        pq.offer(b);
+        pq.offer(c);
+
+        // Decrease B to 0 -> should move up
+        pq.changeKey(b, n -> n.prio = 0);
+        Assertions.assertEquals("B(0)", pq.peek().toString());
+
+        // Increase B to 100 -> should move down
+        pq.changeKey(b, n -> n.prio = 100);
+        Assertions.assertEquals("A(10)", pq.peek().toString());
+    }
+
+    @Test
+    void testDirectMutationWithoutChangeKeyDoesNotReheapByDesign() {
+        // Demonstrates the contract: do NOT mutate comparator fields directly.
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Node a = new Node("A", 5);
+        Node b = new Node("B", 10);
+
+        pq.offer(a);
+        pq.offer(b);
+
+        // Illegally mutate priority directly
+        a.prio = 100; // worse than b now, but heap wasn't notified
+
+        // The heap structure is unchanged; peek still returns A(100) (was A(5) before)
+        // This test documents the behavior/contract rather than relying on it.
+        Assertions.assertEquals("A(100)", pq.peek().toString());
+
+        // Now fix properly via changeKey (no change in value, but triggers reheap)
+        pq.changeKey(a, n -> n.prio = n.prio);
+        Assertions.assertEquals("B(10)", pq.peek().toString());
+    }
+
+    // ------------------------
+    // Identity semantics & duplicates
+    // ------------------------
+
+    @Test
+    void testDuplicateEqualsElementsAreSupportedIdentityMap() {
+        IndexedPriorityQueue<NodeWithEquals> pq = new IndexedPriorityQueue<>(Comparator.comparingInt(n -> n.prio));
+
+        NodeWithEquals x1 = new NodeWithEquals("X1", 7);
+        NodeWithEquals x2 = new NodeWithEquals("X2", 7); // equals to X1 by prio, but different instance
+
+        // With IdentityHashMap internally, both can coexist
+        pq.offer(x1);
+        pq.offer(x2);
+
+        Assertions.assertEquals(2, pq.size());
+        // Poll twice; both 7s should be returned (order between x1/x2 is unspecified)
+        Assertions.assertEquals(7, pq.poll().prio);
+        Assertions.assertEquals(7, pq.poll().prio);
+        Assertions.assertTrue(pq.isEmpty());
+    }
+
+    // ------------------------
+    // Capacity growth
+    // ------------------------
+
+    @Test
+    void testGrowByManyInserts() {
+        IndexedPriorityQueue<Integer> pq = new IndexedPriorityQueue<>();
+        int n = 100; // beyond default capacity (11)
+
+        for (int i = n; i >= 1; i--) {
+            pq.offer(i);
+        }
+
+        Assertions.assertEquals(n, pq.size());
+        // Ensure min-to-max order when polling
+        for (int expected = 1; expected <= n; expected++) {
+            Integer v = pq.poll();
+            Assertions.assertEquals(expected, v);
+        }
+        Assertions.assertTrue(pq.isEmpty());
+        Assertions.assertNull(pq.poll());
+    }
+
+    // ------------------------
+    // remove/contains edge cases
+    // ------------------------
+
+    @Test
+    void testRemoveHeadAndMiddleAndTail() {
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Node a = new Node("A", 1);
+        Node b = new Node("B", 2);
+        Node c = new Node("C", 3);
+        Node d = new Node("D", 4);
+
+        pq.offer(a);
+        pq.offer(b);
+        pq.offer(c);
+        pq.offer(d);
+
+        // remove head
+        Assertions.assertTrue(pq.remove(a));
+        Assertions.assertFalse(pq.contains(a));
+        Assertions.assertEquals("B(2)", pq.peek().toString());
+
+        // remove middle
+        Assertions.assertTrue(pq.remove(c));
+        Assertions.assertFalse(pq.contains(c));
+        Assertions.assertEquals("B(2)", pq.peek().toString());
+
+        // remove tail (last)
+        Assertions.assertTrue(pq.remove(d));
+        Assertions.assertFalse(pq.contains(d));
+        Assertions.assertEquals("B(2)", pq.peek().toString());
+
+        // remove last remaining
+        Assertions.assertTrue(pq.remove(b));
+        Assertions.assertTrue(pq.isEmpty());
+        Assertions.assertNull(pq.peek());
+    }
+
+    // ------------------------
+    // Error / edge cases for coverage
+    // ------------------------
+
+    @Test
+    void testInvalidInitialCapacityThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new IndexedPriorityQueue<Integer>(0, Comparator.naturalOrder()));
+    }
+
+    @Test
+    void testChangeKeyOnMissingElementThrows() {
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Node a = new Node("A", 10);
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> pq.changeKey(a, n -> n.prio = 5));
+    }
+
+    @Test
+    void testDecreaseKeyOnMissingElementThrows() {
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Node a = new Node("A", 10);
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> pq.decreaseKey(a, n -> n.prio = 5));
+    }
+
+    @Test
+    void testIncreaseKeyOnMissingElementThrows() {
+        IndexedPriorityQueue<Node> pq = newNodePQ();
+        Node a = new Node("A", 10);
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> pq.increaseKey(a, n -> n.prio = 15));
+    }
+}

From 9f2b675f3e47c49bf4d1623d9d04f95506e2f813 Mon Sep 17 00:00:00 2001
From: GOPISETTI NAVADEEP <2400030007@kluniversity.in>
Date: Mon, 17 Nov 2025 14:24:20 +0530
Subject: [PATCH 1104/1338] feat: add Sudoku Solver using Backtracking (#7073)

* feat: add Sudoku Solver using Backtracking (issue #6929)

* refactor: remove old Sudoku class from puzzlesandgames package

* Remove old Sudoku implementation and its test class
---
 .../backtracking/SudokuSolver.java            | 157 ++++++++++++++++
 .../thealgorithms/puzzlesandgames/Sudoku.java | 169 ------------------
 .../backtracking/SudokuSolverTest.java        |  53 ++++++
 .../puzzlesandgames/SudokuTest.java           |  38 ----
 4 files changed, 210 insertions(+), 207 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/backtracking/SudokuSolver.java
 delete mode 100644 src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java
 create mode 100644 src/test/java/com/thealgorithms/backtracking/SudokuSolverTest.java
 delete mode 100644 src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java

diff --git a/src/main/java/com/thealgorithms/backtracking/SudokuSolver.java b/src/main/java/com/thealgorithms/backtracking/SudokuSolver.java
new file mode 100644
index 000000000000..543fe2d02b50
--- /dev/null
+++ b/src/main/java/com/thealgorithms/backtracking/SudokuSolver.java
@@ -0,0 +1,157 @@
+package com.thealgorithms.backtracking;
+
+/**
+ * Sudoku Solver using Backtracking Algorithm
+ * Solves a 9x9 Sudoku puzzle by filling empty cells with valid digits (1-9)
+ *
+ * @author Navadeep0007
+ */
+public final class SudokuSolver {
+
+    private static final int GRID_SIZE = 9;
+    private static final int SUBGRID_SIZE = 3;
+    private static final int EMPTY_CELL = 0;
+
+    private SudokuSolver() {
+        // Utility class, prevent instantiation
+    }
+
+    /**
+     * Solves the Sudoku puzzle using backtracking
+     *
+     * @param board 9x9 Sudoku board with 0 representing empty cells
+     * @return true if puzzle is solved, false otherwise
+     */
+    public static boolean solveSudoku(int[][] board) {
+        if (board == null || board.length != GRID_SIZE) {
+            return false;
+        }
+
+        for (int row = 0; row < GRID_SIZE; row++) {
+            if (board[row].length != GRID_SIZE) {
+                return false;
+            }
+        }
+
+        return solve(board);
+    }
+
+    /**
+     * Recursive helper method to solve the Sudoku puzzle
+     *
+     * @param board the Sudoku board
+     * @return true if solution is found, false otherwise
+     */
+    private static boolean solve(int[][] board) {
+        for (int row = 0; row < GRID_SIZE; row++) {
+            for (int col = 0; col < GRID_SIZE; col++) {
+                if (board[row][col] == EMPTY_CELL) {
+                    for (int number = 1; number <= GRID_SIZE; number++) {
+                        if (isValidPlacement(board, row, col, number)) {
+                            board[row][col] = number;
+
+                            if (solve(board)) {
+                                return true;
+                            }
+
+                            // Backtrack
+                            board[row][col] = EMPTY_CELL;
+                        }
+                    }
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Checks if placing a number at given position is valid
+     *
+     * @param board the Sudoku board
+     * @param row row index
+     * @param col column index
+     * @param number number to place (1-9)
+     * @return true if placement is valid, false otherwise
+     */
+    private static boolean isValidPlacement(int[][] board, int row, int col, int number) {
+        return !isNumberInRow(board, row, number) && !isNumberInColumn(board, col, number) && !isNumberInSubgrid(board, row, col, number);
+    }
+
+    /**
+     * Checks if number exists in the given row
+     *
+     * @param board the Sudoku board
+     * @param row row index
+     * @param number number to check
+     * @return true if number exists in row, false otherwise
+     */
+    private static boolean isNumberInRow(int[][] board, int row, int number) {
+        for (int col = 0; col < GRID_SIZE; col++) {
+            if (board[row][col] == number) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Checks if number exists in the given column
+     *
+     * @param board the Sudoku board
+     * @param col column index
+     * @param number number to check
+     * @return true if number exists in column, false otherwise
+     */
+    private static boolean isNumberInColumn(int[][] board, int col, int number) {
+        for (int row = 0; row < GRID_SIZE; row++) {
+            if (board[row][col] == number) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Checks if number exists in the 3x3 subgrid
+     *
+     * @param board the Sudoku board
+     * @param row row index
+     * @param col column index
+     * @param number number to check
+     * @return true if number exists in subgrid, false otherwise
+     */
+    private static boolean isNumberInSubgrid(int[][] board, int row, int col, int number) {
+        int subgridRowStart = row - row % SUBGRID_SIZE;
+        int subgridColStart = col - col % SUBGRID_SIZE;
+
+        for (int i = subgridRowStart; i < subgridRowStart + SUBGRID_SIZE; i++) {
+            for (int j = subgridColStart; j < subgridColStart + SUBGRID_SIZE; j++) {
+                if (board[i][j] == number) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Prints the Sudoku board
+     *
+     * @param board the Sudoku board
+     */
+    public static void printBoard(int[][] board) {
+        for (int row = 0; row < GRID_SIZE; row++) {
+            if (row % SUBGRID_SIZE == 0 && row != 0) {
+                System.out.println("-----------");
+            }
+            for (int col = 0; col < GRID_SIZE; col++) {
+                if (col % SUBGRID_SIZE == 0 && col != 0) {
+                    System.out.print("|");
+                }
+                System.out.print(board[row][col]);
+            }
+            System.out.println();
+        }
+    }
+}
diff --git a/src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java b/src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java
deleted file mode 100644
index fce665c4de00..000000000000
--- a/src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java
+++ /dev/null
@@ -1,169 +0,0 @@
-package com.thealgorithms.puzzlesandgames;
-
-/**
- * A class that provides methods to solve Sudoku puzzles of any n x n size
- * using a backtracking approach, where n must be a perfect square.
- * The algorithm checks for safe number placements in rows, columns,
- * and subgrids (which are sqrt(n) x sqrt(n) in size) and recursively solves the puzzle.
- * Though commonly used for 9x9 grids, it is adaptable to other valid Sudoku dimensions.
- */
-final class Sudoku {
-
-    private Sudoku() {
-    }
-
-    /**
-     * Checks if placing a number in a specific position on the Sudoku board is safe.
-     * The number is considered safe if it does not violate any of the Sudoku rules:
-     * - It should not be present in the same row.
-     * - It should not be present in the same column.
-     * - It should not be present in the corresponding 3x3 subgrid.
-     * - It should not be present in the corresponding subgrid, which is sqrt(n) x sqrt(n) in size (e.g., for a 9x9 grid, the subgrid will be 3x3).
-     *
-     * @param board The current state of the Sudoku board.
-     * @param row   The row index where the number is to be placed.
-     * @param col   The column index where the number is to be placed.
-     * @param num   The number to be placed on the board.
-     * @return True if the placement is safe, otherwise false.
-     */
-    public static boolean isSafe(int[][] board, int row, int col, int num) {
-        // Check the row for duplicates
-        for (int d = 0; d < board.length; d++) {
-            if (board[row][d] == num) {
-                return false;
-            }
-        }
-
-        // Check the column for duplicates
-        for (int r = 0; r < board.length; r++) {
-            if (board[r][col] == num) {
-                return false;
-            }
-        }
-
-        // Check the corresponding 3x3 subgrid for duplicates
-        int sqrt = (int) Math.sqrt(board.length);
-        int boxRowStart = row - row % sqrt;
-        int boxColStart = col - col % sqrt;
-
-        for (int r = boxRowStart; r < boxRowStart + sqrt; r++) {
-            for (int d = boxColStart; d < boxColStart + sqrt; d++) {
-                if (board[r][d] == num) {
-                    return false;
-                }
-            }
-        }
-
-        return true;
-    }
-
-    /**
-     * Solves the Sudoku puzzle using backtracking.
-     * The algorithm finds an empty cell and tries placing numbers
-     * from 1 to n, where n is the size of the board
-     * (for example, from 1 to 9 in a standard 9x9 Sudoku).
-     * The algorithm finds an empty cell and tries placing numbers from 1 to 9.
-     * The standard version of Sudoku uses numbers from 1 to 9, so the algorithm can be
-     * easily modified for other variations of the game.
-     * If a number placement is valid (checked via `isSafe`), the number is
-     * placed and the function recursively attempts to solve the rest of the puzzle.
-     * If no solution is possible, the number is removed (backtracked),
-     * and the process is repeated.
-     *
-     * @param board The current state of the Sudoku board.
-     * @param n     The size of the Sudoku board (typically 9 for a standard puzzle).
-     * @return True if the Sudoku puzzle is solvable, false otherwise.
-     */
-    public static boolean solveSudoku(int[][] board, int n) {
-        int row = -1;
-        int col = -1;
-        boolean isEmpty = true;
-
-        // Find the next empty cell
-        for (int i = 0; i < n; i++) {
-            for (int j = 0; j < n; j++) {
-                if (board[i][j] == 0) {
-                    row = i;
-                    col = j;
-                    isEmpty = false;
-                    break;
-                }
-            }
-            if (!isEmpty) {
-                break;
-            }
-        }
-
-        // No empty space left
-        if (isEmpty) {
-            return true;
-        }
-
-        // Try placing numbers 1 to n in the empty cell (n should be a perfect square)
-        // Eg: n=9 for a standard 9x9 Sudoku puzzle, n=16 for a 16x16 puzzle, etc.
-        for (int num = 1; num <= n; num++) {
-            if (isSafe(board, row, col, num)) {
-                board[row][col] = num;
-                if (solveSudoku(board, n)) {
-                    return true;
-                } else {
-                    // replace it
-                    board[row][col] = 0;
-                }
-            }
-        }
-        return false;
-    }
-
-    /**
-     * Prints the current state of the Sudoku board in a readable format.
-     * Each row is printed on a new line, with numbers separated by spaces.
-     *
-     * @param board The current state of the Sudoku board.
-     * @param n     The size of the Sudoku board (typically 9 for a standard puzzle).
-     */
-    public static void print(int[][] board, int n) {
-        // Print the board in a nxn grid format
-        // if n=9, print the board in a 9x9 grid format
-        // if n=16, print the board in a 16x16 grid format
-        for (int r = 0; r < n; r++) {
-            for (int d = 0; d < n; d++) {
-                System.out.print(board[r][d]);
-                System.out.print(" ");
-            }
-            System.out.print("\n");
-
-            if ((r + 1) % (int) Math.sqrt(n) == 0) {
-                System.out.print("");
-            }
-        }
-    }
-
-    /**
-     * The driver method to demonstrate solving a Sudoku puzzle.
-     * A sample 9x9 Sudoku puzzle is provided, and the program attempts to solve it
-     * using the `solveSudoku` method. If a solution is found, it is printed to the console.
-     *
-     * @param args Command-line arguments (not used in this program).
-     */
-    public static void main(String[] args) {
-        int[][] board = new int[][] {
-            {3, 0, 6, 5, 0, 8, 4, 0, 0},
-            {5, 2, 0, 0, 0, 0, 0, 0, 0},
-            {0, 8, 7, 0, 0, 0, 0, 3, 1},
-            {0, 0, 3, 0, 1, 0, 0, 8, 0},
-            {9, 0, 0, 8, 6, 3, 0, 0, 5},
-            {0, 5, 0, 0, 9, 0, 6, 0, 0},
-            {1, 3, 0, 0, 0, 0, 2, 5, 0},
-            {0, 0, 0, 0, 0, 0, 0, 7, 4},
-            {0, 0, 5, 2, 0, 6, 3, 0, 0},
-        };
-        int n = board.length;
-
-        if (solveSudoku(board, n)) {
-            print(board, n);
-        } else {
-            System.out.println("No solution");
-        }
-    }
-}
diff --git a/src/test/java/com/thealgorithms/backtracking/SudokuSolverTest.java b/src/test/java/com/thealgorithms/backtracking/SudokuSolverTest.java
new file mode 100644
index 000000000000..75d3eae08629
--- /dev/null
+++ b/src/test/java/com/thealgorithms/backtracking/SudokuSolverTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.backtracking;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class SudokuSolverTest {
+
+    @Test
+    void testSolveSudokuEasyPuzzle() {
+        int[][] board = {{5, 3, 0, 0, 7, 0, 0, 0, 0}, {6, 0, 0, 1, 9, 5, 0, 0, 0}, {0, 9, 8, 0, 0, 0, 0, 6, 0}, {8, 0, 0, 0, 6, 0, 0, 0, 3}, {4, 0, 0, 8, 0, 3, 0, 0, 1}, {7, 0, 0, 0, 2, 0, 0, 0, 6}, {0, 6, 0, 0, 0, 0, 2, 8, 0}, {0, 0, 0, 4, 1, 9, 0, 0, 5}, {0, 0, 0, 0, 8, 0, 0, 7, 9}};
+
+        assertTrue(SudokuSolver.solveSudoku(board));
+
+        int[][] expected = {{5, 3, 4, 6, 7, 8, 9, 1, 2}, {6, 7, 2, 1, 9, 5, 3, 4, 8}, {1, 9, 8, 3, 4, 2, 5, 6, 7}, {8, 5, 9, 7, 6, 1, 4, 2, 3}, {4, 2, 6, 8, 5, 3, 7, 9, 1}, {7, 1, 3, 9, 2, 4, 8, 5, 6}, {9, 6, 1, 5, 3, 7, 2, 8, 4}, {2, 8, 7, 4, 1, 9, 6, 3, 5}, {3, 4, 5, 2, 8, 6, 1, 7, 9}};
+
+        assertArrayEquals(expected, board);
+    }
+
+    @Test
+    void testSolveSudokuHardPuzzle() {
+        int[][] board = {{0, 0, 0, 0, 0, 0, 6, 8, 0}, {0, 0, 0, 0, 7, 3, 0, 0, 9}, {3, 0, 9, 0, 0, 0, 0, 4, 5}, {4, 9, 0, 0, 0, 0, 0, 0, 0}, {8, 0, 3, 0, 5, 0, 9, 0, 2}, {0, 0, 0, 0, 0, 0, 0, 3, 6}, {9, 6, 0, 0, 0, 0, 3, 0, 8}, {7, 0, 0, 6, 8, 0, 0, 0, 0}, {0, 2, 8, 0, 0, 0, 0, 0, 0}};
+
+        assertTrue(SudokuSolver.solveSudoku(board));
+    }
+
+    @Test
+    void testSolveSudokuAlreadySolved() {
+        int[][] board = {{5, 3, 4, 6, 7, 8, 9, 1, 2}, {6, 7, 2, 1, 9, 5, 3, 4, 8}, {1, 9, 8, 3, 4, 2, 5, 6, 7}, {8, 5, 9, 7, 6, 1, 4, 2, 3}, {4, 2, 6, 8, 5, 3, 7, 9, 1}, {7, 1, 3, 9, 2, 4, 8, 5, 6}, {9, 6, 1, 5, 3, 7, 2, 8, 4}, {2, 8, 7, 4, 1, 9, 6, 3, 5}, {3, 4, 5, 2, 8, 6, 1, 7, 9}};
+
+        assertTrue(SudokuSolver.solveSudoku(board));
+    }
+
+    @Test
+    void testSolveSudokuInvalidSize() {
+        int[][] board = {{1, 2, 3}, {4, 5, 6}};
+        assertFalse(SudokuSolver.solveSudoku(board));
+    }
+
+    @Test
+    void testSolveSudokuNullBoard() {
+        assertFalse(SudokuSolver.solveSudoku(null));
+    }
+
+    @Test
+    void testSolveSudokuEmptyBoard() {
+        int[][] board = {{0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0}};
+
+        assertTrue(SudokuSolver.solveSudoku(board));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java b/src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java
deleted file mode 100644
index 7fb96dcf805f..000000000000
--- a/src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java
+++ /dev/null
@@ -1,38 +0,0 @@
-package com.thealgorithms.puzzlesandgames;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
-import org.junit.jupiter.api.Test;
-
-public class SudokuTest {
-
-    @Test
-    void testIsSafe2() {
-        int[][] board = {{3, 0, 6, 5, 0, 8, 4, 0, 0}, {5, 2, 0, 0, 0, 0, 0, 0, 0}, {0, 8, 7, 0, 0, 0, 0, 3, 1}, {0, 0, 3, 0, 1, 0, 0, 8, 0}, {9, 0, 0, 8, 6, 3, 0, 0, 5}, {0, 5, 0, 0, 9, 0, 6, 0, 0}, {1, 3, 0, 0, 0, 0, 2, 5, 0}, {0, 0, 0, 0, 0, 0, 0, 7, 4}, {0, 0, 5, 2, 0, 6, 3, 0, 0}};
-
-        assertFalse(Sudoku.isSafe(board, 0, 1, 3));
-        assertTrue(Sudoku.isSafe(board, 1, 2, 1));
-        assertThrows(ArrayIndexOutOfBoundsException.class, () -> { Sudoku.isSafe(board, 10, 10, 5); });
-        assertThrows(ArrayIndexOutOfBoundsException.class, () -> { Sudoku.isSafe(board, -1, 0, 5); });
-    }
-
-    @Test
-    void testSolveSudoku() {
-        int[][] board = {{3, 0, 6, 5, 0, 8, 4, 0, 0}, {5, 2, 0, 0, 0, 0, 0, 0, 0}, {0, 8, 7, 0, 0, 0, 0, 3, 1}, {0, 0, 3, 0, 1, 0, 0, 8, 0}, {9, 0, 0, 8, 6, 3, 0, 0, 5}, {0, 5, 0, 0, 9, 0, 6, 0, 0}, {1, 3, 0, 0, 0, 0, 2, 5, 0}, {0, 0, 0, 0, 0, 0, 0, 7, 4}, {0, 0, 5, 2, 0, 6, 3, 0, 0}};
-
-        assertTrue(Sudoku.solveSudoku(board, board.length));
-        assertEquals(1, board[0][1]);
-        assertThrows(ArrayIndexOutOfBoundsException.class, () -> { Sudoku.solveSudoku(board, 10); });
-        assertTrue(Sudoku.solveSudoku(board, -1));
-    }
-
-    @Test
-    void testUnsolvableSudoku() {
-        int[][] unsolvableBoard = {{5, 1, 6, 8, 4, 9, 7, 3, 2}, {3, 0, 7, 6, 0, 5, 0, 0, 0}, {8, 0, 9, 7, 0, 0, 0, 6, 5}, {1, 3, 5, 0, 6, 0, 9, 0, 7}, {4, 7, 2, 5, 9, 1, 0, 0, 6}, {9, 6, 8, 3, 7, 0, 0, 5, 0}, {2, 5, 3, 1, 8, 6, 0, 7, 4}, {6, 8, 4, 2, 5, 7, 3, 9, 0}, {7, 9, 1, 4, 3, 0, 5, 0, 0}};
-
-        assertFalse(Sudoku.solveSudoku(unsolvableBoard, unsolvableBoard.length));
-    }
-}

From 1c97ad8015855780e7d86248dd2938ef38caf2d4 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 17 Nov 2025 22:16:07 +0100
Subject: [PATCH 1105/1338] chore(deps): bump org.apache.commons:commons-lang3
 from 3.19.0 to 3.20.0 (#7076)

Bumps org.apache.commons:commons-lang3 from 3.19.0 to 3.20.0.

---
updated-dependencies:
- dependency-name: org.apache.commons:commons-lang3
  dependency-version: 3.20.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 6126bbe4d6c5..774db2ec4403 100644
--- a/pom.xml
+++ b/pom.xml
@@ -48,7 +48,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
-            <version>3.19.0</version>
+            <version>3.20.0</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>

From 3519e396af269683a42796ef653b37abdcd7d791 Mon Sep 17 00:00:00 2001
From: shreeya-g10 <shreeyakiran04@gmail.com>
Date: Wed, 19 Nov 2025 21:50:46 +0530
Subject: [PATCH 1106/1338] backtracking: add unique permutation algorithm with
 test cases (#7078)

* Add unique permutation algorithm and test cases

* Fix: add braces for checkstyle

* Apply clang-format
---
 .../backtracking/UniquePermutation.java       | 62 +++++++++++++++++++
 .../backtracking/UniquePermutationTest.java   | 31 ++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/backtracking/UniquePermutation.java
 create mode 100644 src/test/java/com/thealgorithms/backtracking/UniquePermutationTest.java

diff --git a/src/main/java/com/thealgorithms/backtracking/UniquePermutation.java b/src/main/java/com/thealgorithms/backtracking/UniquePermutation.java
new file mode 100644
index 000000000000..4804e247ab03
--- /dev/null
+++ b/src/main/java/com/thealgorithms/backtracking/UniquePermutation.java
@@ -0,0 +1,62 @@
+package com.thealgorithms.backtracking;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Generates all UNIQUE permutations of a string, even when duplicate characters exist.
+ *
+ * Example:
+ *   Input: "AAB"
+ *   Output: ["AAB", "ABA", "BAA"]
+ *
+ * Time Complexity: O(n! * n)
+ */
+public final class UniquePermutation {
+
+    private UniquePermutation() {
+        // Prevent instantiation
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    public static List<String> generateUniquePermutations(String input) {
+        List<String> result = new ArrayList<>();
+        if (input == null) {
+            return result;
+        }
+
+        char[] chars = input.toCharArray();
+        Arrays.sort(chars); // important: sort to detect duplicates
+
+        backtrack(chars, new boolean[chars.length], new StringBuilder(), result);
+        return result;
+    }
+
+    private static void backtrack(char[] chars, boolean[] used, StringBuilder current, List<String> result) {
+
+        if (current.length() == chars.length) {
+            result.add(current.toString());
+            return;
+        }
+
+        for (int i = 0; i < chars.length; i++) {
+
+            // skip duplicates
+            if (i > 0 && chars[i] == chars[i - 1] && !used[i - 1]) {
+                continue;
+            }
+
+            if (!used[i]) {
+                used[i] = true;
+                current.append(chars[i]);
+
+                backtrack(chars, used, current, result);
+
+                // undo changes
+                used[i] = false;
+                current.deleteCharAt(current.length() - 1);
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/backtracking/UniquePermutationTest.java b/src/test/java/com/thealgorithms/backtracking/UniquePermutationTest.java
new file mode 100644
index 000000000000..c8e7cd0af0dd
--- /dev/null
+++ b/src/test/java/com/thealgorithms/backtracking/UniquePermutationTest.java
@@ -0,0 +1,31 @@
+package com.thealgorithms.backtracking;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class UniquePermutationTest {
+
+    @Test
+    void testUniquePermutationsAab() {
+        List<String> expected = Arrays.asList("AAB", "ABA", "BAA");
+        List<String> result = UniquePermutation.generateUniquePermutations("AAB");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testUniquePermutationsAbc() {
+        List<String> expected = Arrays.asList("ABC", "ACB", "BAC", "BCA", "CAB", "CBA");
+        List<String> result = UniquePermutation.generateUniquePermutations("ABC");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testEmptyString() {
+        List<String> expected = Arrays.asList("");
+        List<String> result = UniquePermutation.generateUniquePermutations("");
+        assertEquals(expected, result);
+    }
+}

From e37a7ab6ce87c7cf13274366dca536d34cfc5668 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Date: Wed, 19 Nov 2025 17:25:09 +0100
Subject: [PATCH 1107/1338] Update DIRECTORY.md (#7070)

Co-authored-by: alxkm <alxkm@users.noreply.github.com>
---
 DIRECTORY.md | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index f15d65c18c3f..042efa72addc 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -24,6 +24,8 @@
           - 📄 [Permutation](src/main/java/com/thealgorithms/backtracking/Permutation.java)
           - 📄 [PowerSum](src/main/java/com/thealgorithms/backtracking/PowerSum.java)
           - 📄 [SubsequenceFinder](src/main/java/com/thealgorithms/backtracking/SubsequenceFinder.java)
+          - 📄 [SudokuSolver](src/main/java/com/thealgorithms/backtracking/SudokuSolver.java)
+          - 📄 [UniquePermutation](src/main/java/com/thealgorithms/backtracking/UniquePermutation.java)
           - 📄 [WordPatternMatcher](src/main/java/com/thealgorithms/backtracking/WordPatternMatcher.java)
           - 📄 [WordSearch](src/main/java/com/thealgorithms/backtracking/WordSearch.java)
         - 📁 **bitmanipulation**
@@ -133,6 +135,7 @@
           - 📄 [PhoneticAlphabetConverter](src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java)
           - 📄 [RgbHsvConversion](src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java)
           - 📄 [RomanToInteger](src/main/java/com/thealgorithms/conversions/RomanToInteger.java)
+          - 📄 [TemperatureConverter](src/main/java/com/thealgorithms/conversions/TemperatureConverter.java)
           - 📄 [TimeConverter](src/main/java/com/thealgorithms/conversions/TimeConverter.java)
           - 📄 [TurkishToLatinConversion](src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java)
           - 📄 [UnitConversions](src/main/java/com/thealgorithms/conversions/UnitConversions.java)
@@ -208,6 +211,7 @@
             - 📄 [GenericHeap](src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java)
             - 📄 [Heap](src/main/java/com/thealgorithms/datastructures/heaps/Heap.java)
             - 📄 [HeapElement](src/main/java/com/thealgorithms/datastructures/heaps/HeapElement.java)
+            - 📄 [IndexedPriorityQueue](src/main/java/com/thealgorithms/datastructures/heaps/IndexedPriorityQueue.java)
             - 📄 [KthElementFinder](src/main/java/com/thealgorithms/datastructures/heaps/KthElementFinder.java)
             - 📄 [LeftistHeap](src/main/java/com/thealgorithms/datastructures/heaps/LeftistHeap.java)
             - 📄 [MaxHeap](src/main/java/com/thealgorithms/datastructures/heaps/MaxHeap.java)
@@ -507,6 +511,7 @@
           - 📄 [PiNilakantha](src/main/java/com/thealgorithms/maths/PiNilakantha.java)
           - 📄 [PollardRho](src/main/java/com/thealgorithms/maths/PollardRho.java)
           - 📄 [Pow](src/main/java/com/thealgorithms/maths/Pow.java)
+          - 📄 [PowerOfFour](src/main/java/com/thealgorithms/maths/PowerOfFour.java)
           - 📄 [PowerOfTwoOrNot](src/main/java/com/thealgorithms/maths/PowerOfTwoOrNot.java)
           - 📄 [PowerUsingRecursion](src/main/java/com/thealgorithms/maths/PowerUsingRecursion.java)
           - 📁 **Prime**
@@ -525,6 +530,7 @@
           - 📄 [SieveOfAtkin](src/main/java/com/thealgorithms/maths/SieveOfAtkin.java)
           - 📄 [SieveOfEratosthenes](src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java)
           - 📄 [SimpsonIntegration](src/main/java/com/thealgorithms/maths/SimpsonIntegration.java)
+          - 📄 [SmithNumber](src/main/java/com/thealgorithms/maths/SmithNumber.java)
           - 📄 [SolovayStrassenPrimalityTest](src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java)
           - 📄 [SquareRootWithBabylonianMethod](src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java)
           - 📄 [SquareRootWithNewtonRaphsonMethod](src/main/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonMethod.java)
@@ -622,7 +628,6 @@
           - 📄 [ProjectileMotion](src/main/java/com/thealgorithms/physics/ProjectileMotion.java)
           - 📄 [SimplePendulumRK4](src/main/java/com/thealgorithms/physics/SimplePendulumRK4.java)
         - 📁 **puzzlesandgames**
-          - 📄 [Sudoku](src/main/java/com/thealgorithms/puzzlesandgames/Sudoku.java)
           - 📄 [TowerOfHanoi](src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java)
           - 📄 [WordBoggle](src/main/java/com/thealgorithms/puzzlesandgames/WordBoggle.java)
         - 📁 **randomized**
@@ -842,6 +847,8 @@
           - 📄 [PermutationTest](src/test/java/com/thealgorithms/backtracking/PermutationTest.java)
           - 📄 [PowerSumTest](src/test/java/com/thealgorithms/backtracking/PowerSumTest.java)
           - 📄 [SubsequenceFinderTest](src/test/java/com/thealgorithms/backtracking/SubsequenceFinderTest.java)
+          - 📄 [SudokuSolverTest](src/test/java/com/thealgorithms/backtracking/SudokuSolverTest.java)
+          - 📄 [UniquePermutationTest](src/test/java/com/thealgorithms/backtracking/UniquePermutationTest.java)
           - 📄 [WordPatternMatcherTest](src/test/java/com/thealgorithms/backtracking/WordPatternMatcherTest.java)
           - 📄 [WordSearchTest](src/test/java/com/thealgorithms/backtracking/WordSearchTest.java)
         - 📁 **bitmanipulation**
@@ -944,6 +951,7 @@
           - 📄 [OctalToHexadecimalTest](src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
           - 📄 [PhoneticAlphabetConverterTest](src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java)
           - 📄 [RomanToIntegerTest](src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java)
+          - 📄 [TemperatureConverterTest](src/test/java/com/thealgorithms/conversions/TemperatureConverterTest.java)
           - 📄 [TimeConverterTest](src/test/java/com/thealgorithms/conversions/TimeConverterTest.java)
           - 📄 [TurkishToLatinConversionTest](src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java)
           - 📄 [UnitConversionsTest](src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java)
@@ -1009,6 +1017,7 @@
             - 📄 [FibonacciHeapTest](src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
             - 📄 [GenericHeapTest](src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java)
             - 📄 [HeapElementTest](src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java)
+            - 📄 [IndexedPriorityQueueTest](src/test/java/com/thealgorithms/datastructures/heaps/IndexedPriorityQueueTest.java)
             - 📄 [KthElementFinderTest](src/test/java/com/thealgorithms/datastructures/heaps/KthElementFinderTest.java)
             - 📄 [LeftistHeapTest](src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
             - 📄 [MaxHeapTest](src/test/java/com/thealgorithms/datastructures/heaps/MaxHeapTest.java)
@@ -1279,6 +1288,7 @@
           - 📄 [PiApproximationTest](src/test/java/com/thealgorithms/maths/PiApproximationTest.java)
           - 📄 [PollardRhoTest](src/test/java/com/thealgorithms/maths/PollardRhoTest.java)
           - 📄 [PowTest](src/test/java/com/thealgorithms/maths/PowTest.java)
+          - 📄 [PowerOfFourTest](src/test/java/com/thealgorithms/maths/PowerOfFourTest.java)
           - 📄 [PowerOfTwoOrNotTest](src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java)
           - 📄 [PowerUsingRecursionTest](src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java)
           - 📄 [PronicNumberTest](src/test/java/com/thealgorithms/maths/PronicNumberTest.java)
@@ -1288,6 +1298,7 @@
           - 📄 [SecondMinMaxTest](src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java)
           - 📄 [SieveOfAtkinTest](src/test/java/com/thealgorithms/maths/SieveOfAtkinTest.java)
           - 📄 [SieveOfEratosthenesTest](src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java)
+          - 📄 [SmithNumberTest](src/test/java/com/thealgorithms/maths/SmithNumberTest.java)
           - 📄 [SolovayStrassenPrimalityTestTest](src/test/java/com/thealgorithms/maths/SolovayStrassenPrimalityTestTest.java)
           - 📄 [SquareFreeIntegerTest](src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java)
           - 📄 [SquareRootWithNewtonRaphsonTestMethod](src/test/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonTestMethod.java)
@@ -1377,7 +1388,6 @@
           - 📄 [ProjectileMotionTest](src/test/java/com/thealgorithms/physics/ProjectileMotionTest.java)
           - 📄 [SimplePendulumRK4Test](src/test/java/com/thealgorithms/physics/SimplePendulumRK4Test.java)
         - 📁 **puzzlesandgames**
-          - 📄 [SudokuTest](src/test/java/com/thealgorithms/puzzlesandgames/SudokuTest.java)
           - 📄 [TowerOfHanoiTest](src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java)
           - 📄 [WordBoggleTest](src/test/java/com/thealgorithms/puzzlesandgames/WordBoggleTest.java)
         - 📁 **randomized**

From fba6292ebc849dc8311ab24d8bcbf6e3dacbc105 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 19 Nov 2025 19:31:32 +0100
Subject: [PATCH 1108/1338] chore: pin infer to more recent hash (#7079)

* chore: pin infer to more recent hash

* chore: suppress new infer warnings
---
 .github/workflows/infer.yml | 2 +-
 .inferconfig                | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index 3df7c4b1fc9e..329fb0cd720a 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -44,7 +44,7 @@ jobs:
           cd ..
           git clone https://github.com/facebook/infer.git
           cd infer
-          git checkout 01aaa268f9d38723ba69c139e10f9e2a04b40b1c
+          git checkout 02c2c43b71e4c5110c0be841e66153942fda06c9
           ./build-infer.sh java
           cp -r infer ../Java
 
diff --git a/.inferconfig b/.inferconfig
index 6af4f9e2e818..239172177b38 100644
--- a/.inferconfig
+++ b/.inferconfig
@@ -1,6 +1,8 @@
 {
     "report-block-list-path-regex": [
         "src/main/java/com/thealgorithms/ciphers/a5/CompositeLFSR.java",
+        "src/main/java/com/thealgorithms/compression/ArithmeticCoding.java",
+        "src/main/java/com/thealgorithms/datastructures/caches/FIFOCache.java",
         "src/main/java/com/thealgorithms/datastructures/crdt/GCounter.java",
         "src/main/java/com/thealgorithms/datastructures/crdt/PNCounter.java",
         "src/main/java/com/thealgorithms/datastructures/graphs/KahnsAlgorithm.java",
@@ -8,15 +10,18 @@
         "src/main/java/com/thealgorithms/datastructures/lists/DoublyLinkedList.java",
         "src/main/java/com/thealgorithms/datastructures/trees/CreateBinaryTreeFromInorderPreorder.java",
         "src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java",
+        "src/main/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistance.java",
         "src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java",
         "src/main/java/com/thealgorithms/maths/SimpsonIntegration.java",
         "src/main/java/com/thealgorithms/others/Dijkstra.java",
         "src/main/java/com/thealgorithms/sorts/TopologicalSort.java",
         "src/main/java/com/thealgorithms/strings/AhoCorasick.java",
+        "src/test/java/com/thealgorithms/compression/ShannonFanoTest.java",
         "src/test/java/com/thealgorithms/datastructures/caches/LRUCacheTest.java",
         "src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java",
         "src/test/java/com/thealgorithms/datastructures/trees/KDTreeTest.java",
         "src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java",
+        "src/test/java/com/thealgorithms/others/HuffmanTest.java",
         "src/test/java/com/thealgorithms/searches/QuickSelectTest.java",
         "src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java",
         "src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java"

From e6c576c50aac098f84a1e6a02d81c714750100ab Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 20 Nov 2025 19:44:44 +0100
Subject: [PATCH 1109/1338] chore(deps): bump actions/checkout from 5 to 6 in
 /.github/workflows (#7084)

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml              | 2 +-
 .github/workflows/clang-format-lint.yml  | 2 +-
 .github/workflows/codeql.yml             | 4 ++--
 .github/workflows/infer.yml              | 2 +-
 .github/workflows/project_structure.yml  | 2 +-
 .github/workflows/update-directorymd.yml | 2 +-
 6 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 39bde758d68e..c5f200c12836 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -8,7 +8,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up JDK
         uses: actions/setup-java@v5
         with:
diff --git a/.github/workflows/clang-format-lint.yml b/.github/workflows/clang-format-lint.yml
index ca014e115282..dc0c9754ed1b 100644
--- a/.github/workflows/clang-format-lint.yml
+++ b/.github/workflows/clang-format-lint.yml
@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: DoozyX/clang-format-lint-action@v0.20
       with:
         source: './src'
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 3a4cfd829b6b..152d0d766fd2 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -21,7 +21,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Set up JDK
         uses: actions/setup-java@v5
@@ -52,7 +52,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v4
diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index 329fb0cd720a..c85b1d225f72 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -15,7 +15,7 @@ jobs:
   run_infer:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Set up JDK
         uses: actions/setup-java@v5
diff --git a/.github/workflows/project_structure.yml b/.github/workflows/project_structure.yml
index f9fb82a2781c..5aadc6353791 100644
--- a/.github/workflows/project_structure.yml
+++ b/.github/workflows/project_structure.yml
@@ -15,7 +15,7 @@ jobs:
   check_structure:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: '3.13'
diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index 6692a884a867..f6c91abe0e74 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Run Directory Tree Generator
         uses: DenizAltunkapan/directory-tree-generator@v2

From fa8ea8e6143ee788eb752178b2252faa41e546cf Mon Sep 17 00:00:00 2001
From: KANAKALA SAI KIRAN <2400030639@kluniversity.in>
Date: Sat, 22 Nov 2025 15:14:34 +0530
Subject: [PATCH 1110/1338] Feature/centroid decomposition (#7086)

* feat: Add Centroid Decomposition for trees (#7054)

- Implement CentroidDecomposition with O(N log N) construction
- Add CentroidTree class with parent tracking and query methods
- Include buildFromEdges helper for easy tree construction
- Add comprehensive test suite with 20+ test cases
- Cover edge cases, validation, and various tree structures

Closes #7054

* feat: Add Centroid Decomposition for trees (#7054)

- Implement CentroidDecomposition with O(N log N) construction
- Add CentroidTree class with parent tracking and query methods
- Include buildFromEdges helper for easy tree construction
- Add comprehensive test suite with 20+ test cases
- Cover edge cases, validation, and various tree structures

Closes #7054

* fix: Remove trailing whitespace from CentroidDecompositionTest

* fix: Remove trailing whitespace and add newlines at end of files

* fix: Format code to comply with clang-format and checkstyle requirements

* style: Fix lambda formatting in test assertions

- Change single-line lambdas to multi-line format
- Align with repository code style guidelines

* style: Apply clang-format to match repository style guide

- Format code according to .clang-format configuration
- Use single-line lambdas as allowed by AllowShortLambdasOnASingleLine: All
- Apply 4-space indentation
- Ensure proper line endings
---
 .../trees/CentroidDecomposition.java          | 217 ++++++++++++++++
 .../trees/CentroidDecompositionTest.java      | 236 ++++++++++++++++++
 2 files changed, 453 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/trees/CentroidDecomposition.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/CentroidDecompositionTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/CentroidDecomposition.java b/src/main/java/com/thealgorithms/datastructures/trees/CentroidDecomposition.java
new file mode 100644
index 000000000000..0b29dd6f5f5e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/trees/CentroidDecomposition.java
@@ -0,0 +1,217 @@
+package com.thealgorithms.datastructures.trees;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Centroid Decomposition is a divide-and-conquer technique for trees.
+ * It recursively partitions a tree by finding centroids - nodes whose removal
+ * creates balanced subtrees (each with at most N/2 nodes).
+ *
+ * <p>
+ * Time Complexity: O(N log N) for construction
+ * Space Complexity: O(N)
+ *
+ * <p>
+ * Applications:
+ * - Distance queries on trees
+ * - Path counting problems
+ * - Nearest neighbor searches
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Centroid_decomposition">Centroid Decomposition</a>
+ * @see <a href="https://codeforces.com/blog/entry/81661">Centroid Decomposition Tutorial</a>
+ * @author lens161
+ */
+public final class CentroidDecomposition {
+
+    private CentroidDecomposition() {
+    }
+
+    /**
+     * Represents the centroid tree structure.
+     */
+    public static final class CentroidTree {
+        private final int n;
+        private final List<List<Integer>> adj;
+        private final int[] parent;
+        private final int[] subtreeSize;
+        private final boolean[] removed;
+        private int root;
+
+        /**
+         * Constructs a centroid tree from an adjacency list.
+         *
+         * @param adj adjacency list representation of the tree (0-indexed)
+         * @throws IllegalArgumentException if tree is empty or null
+         */
+        public CentroidTree(List<List<Integer>> adj) {
+            if (adj == null || adj.isEmpty()) {
+                throw new IllegalArgumentException("Tree cannot be empty or null");
+            }
+
+            this.n = adj.size();
+            this.adj = adj;
+            this.parent = new int[n];
+            this.subtreeSize = new int[n];
+            this.removed = new boolean[n];
+            Arrays.fill(parent, -1);
+
+            // Build centroid tree starting from node 0
+            this.root = decompose(0, -1);
+        }
+
+        /**
+         * Recursively builds the centroid tree.
+         *
+         * @param u current node
+         * @param p parent in centroid tree
+         * @return centroid of current component
+         */
+        private int decompose(int u, int p) {
+            int size = getSubtreeSize(u, -1);
+            int centroid = findCentroid(u, -1, size);
+
+            removed[centroid] = true;
+            parent[centroid] = p;
+
+            // Recursively decompose each subtree
+            for (int v : adj.get(centroid)) {
+                if (!removed[v]) {
+                    decompose(v, centroid);
+                }
+            }
+
+            return centroid;
+        }
+
+        /**
+         * Calculates subtree size from node u.
+         *
+         * @param u current node
+         * @param p parent node (-1 for root)
+         * @return size of subtree rooted at u
+         */
+        private int getSubtreeSize(int u, int p) {
+            subtreeSize[u] = 1;
+            for (int v : adj.get(u)) {
+                if (v != p && !removed[v]) {
+                    subtreeSize[u] += getSubtreeSize(v, u);
+                }
+            }
+            return subtreeSize[u];
+        }
+
+        /**
+         * Finds the centroid of a subtree.
+         * A centroid is a node whose removal creates components with size &lt;= totalSize/2.
+         *
+         * @param u current node
+         * @param p parent node
+         * @param totalSize total size of current component
+         * @return centroid node
+         */
+        private int findCentroid(int u, int p, int totalSize) {
+            for (int v : adj.get(u)) {
+                if (v != p && !removed[v] && subtreeSize[v] > totalSize / 2) {
+                    return findCentroid(v, u, totalSize);
+                }
+            }
+            return u;
+        }
+
+        /**
+         * Gets the parent of a node in the centroid tree.
+         *
+         * @param node the node
+         * @return parent node in centroid tree, or -1 if root
+         */
+        public int getParent(int node) {
+            if (node < 0 || node >= n) {
+                throw new IllegalArgumentException("Invalid node: " + node);
+            }
+            return parent[node];
+        }
+
+        /**
+         * Gets the root of the centroid tree.
+         *
+         * @return root node
+         */
+        public int getRoot() {
+            return root;
+        }
+
+        /**
+         * Gets the number of nodes in the tree.
+         *
+         * @return number of nodes
+         */
+        public int size() {
+            return n;
+        }
+
+        /**
+         * Returns the centroid tree structure as a string.
+         * Format: node -&gt; parent (or ROOT for root node)
+         *
+         * @return string representation
+         */
+        @Override
+        public String toString() {
+            StringBuilder sb = new StringBuilder("Centroid Tree:\n");
+            for (int i = 0; i < n; i++) {
+                sb.append("Node ").append(i).append(" -> ");
+                if (parent[i] == -1) {
+                    sb.append("ROOT");
+                } else {
+                    sb.append("Parent ").append(parent[i]);
+                }
+                sb.append("\n");
+            }
+            return sb.toString();
+        }
+    }
+
+    /**
+     * Creates a centroid tree from an edge list.
+     *
+     * @param n number of nodes (0-indexed: 0 to n-1)
+     * @param edges list of edges where each edge is [u, v]
+     * @return CentroidTree object
+     * @throws IllegalArgumentException if n &lt;= 0 or edges is invalid
+     */
+    public static CentroidTree buildFromEdges(int n, int[][] edges) {
+        if (n <= 0) {
+            throw new IllegalArgumentException("Number of nodes must be positive");
+        }
+        if (edges == null) {
+            throw new IllegalArgumentException("Edges cannot be null");
+        }
+        if (edges.length != n - 1) {
+            throw new IllegalArgumentException("Tree must have exactly n-1 edges");
+        }
+
+        List<List<Integer>> adj = new ArrayList<>();
+        for (int i = 0; i < n; i++) {
+            adj.add(new ArrayList<>());
+        }
+
+        for (int[] edge : edges) {
+            if (edge.length != 2) {
+                throw new IllegalArgumentException("Each edge must have exactly 2 nodes");
+            }
+            int u = edge[0];
+            int v = edge[1];
+
+            if (u < 0 || u >= n || v < 0 || v >= n) {
+                throw new IllegalArgumentException("Invalid node in edge: [" + u + ", " + v + "]");
+            }
+
+            adj.get(u).add(v);
+            adj.get(v).add(u);
+        }
+
+        return new CentroidTree(adj);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/CentroidDecompositionTest.java b/src/test/java/com/thealgorithms/datastructures/trees/CentroidDecompositionTest.java
new file mode 100644
index 000000000000..43d732e54f34
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/CentroidDecompositionTest.java
@@ -0,0 +1,236 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test cases for CentroidDecomposition
+ *
+ * @author lens161
+ */
+class CentroidDecompositionTest {
+
+    @Test
+    void testSingleNode() {
+        // Tree with just one node
+        int[][] edges = {};
+        CentroidDecomposition.CentroidTree tree = CentroidDecomposition.buildFromEdges(1, edges);
+
+        assertEquals(1, tree.size());
+        assertEquals(0, tree.getRoot());
+        assertEquals(-1, tree.getParent(0));
+    }
+
+    @Test
+    void testTwoNodes() {
+        // Simple tree: 0 - 1
+        int[][] edges = {{0, 1}};
+        CentroidDecomposition.CentroidTree tree = CentroidDecomposition.buildFromEdges(2, edges);
+
+        assertEquals(2, tree.size());
+        int root = tree.getRoot();
+        assertTrue(root == 0 || root == 1, "Root should be either node 0 or 1");
+
+        // One node should be root, other should have the root as parent
+        int nonRoot = (root == 0) ? 1 : 0;
+        assertEquals(-1, tree.getParent(root));
+        assertEquals(root, tree.getParent(nonRoot));
+    }
+
+    @Test
+    void testLinearTree() {
+        // Linear tree: 0 - 1 - 2 - 3 - 4
+        int[][] edges = {{0, 1}, {1, 2}, {2, 3}, {3, 4}};
+        CentroidDecomposition.CentroidTree tree = CentroidDecomposition.buildFromEdges(5, edges);
+
+        assertEquals(5, tree.size());
+        // For a linear tree of 5 nodes, the centroid should be the middle node (node 2)
+        assertEquals(2, tree.getRoot());
+        assertEquals(-1, tree.getParent(2));
+    }
+
+    @Test
+    void testBalancedBinaryTree() {
+        // Balanced binary tree:
+        //       0
+        //      / \
+        //     1   2
+        //    / \
+        //   3   4
+        int[][] edges = {{0, 1}, {0, 2}, {1, 3}, {1, 4}};
+        CentroidDecomposition.CentroidTree tree = CentroidDecomposition.buildFromEdges(5, edges);
+
+        assertEquals(5, tree.size());
+        // Root should be 0 or 1 (both are valid centroids)
+        int root = tree.getRoot();
+        assertTrue(root == 0 || root == 1);
+        assertEquals(-1, tree.getParent(root));
+
+        // All nodes should have a parent in centroid tree except root
+        for (int i = 0; i < 5; i++) {
+            if (i != root) {
+                assertTrue(tree.getParent(i) >= 0 && tree.getParent(i) < 5);
+            }
+        }
+    }
+
+    @Test
+    void testStarTree() {
+        // Star tree: center node 0 connected to 1, 2, 3, 4
+        int[][] edges = {{0, 1}, {0, 2}, {0, 3}, {0, 4}};
+        CentroidDecomposition.CentroidTree tree = CentroidDecomposition.buildFromEdges(5, edges);
+
+        assertEquals(5, tree.size());
+        // Center node (0) should be the root
+        assertEquals(0, tree.getRoot());
+
+        // All other nodes should have 0 as parent
+        for (int i = 1; i < 5; i++) {
+            assertEquals(0, tree.getParent(i));
+        }
+    }
+
+    @Test
+    void testCompleteTree() {
+        // Complete binary tree of 7 nodes:
+        //       0
+        //      / \
+        //     1   2
+        //    / \ / \
+        //   3  4 5  6
+        int[][] edges = {{0, 1}, {0, 2}, {1, 3}, {1, 4}, {2, 5}, {2, 6}};
+        CentroidDecomposition.CentroidTree tree = CentroidDecomposition.buildFromEdges(7, edges);
+
+        assertEquals(7, tree.size());
+        assertEquals(0, tree.getRoot()); // Root should be the center
+
+        // Verify all nodes are reachable in centroid tree
+        boolean[] visited = new boolean[7];
+        visited[0] = true;
+        for (int i = 1; i < 7; i++) {
+            int parent = tree.getParent(i);
+            assertTrue(parent >= 0 && parent < 7);
+            assertTrue(visited[parent], "Parent should be processed before child");
+            visited[i] = true;
+        }
+    }
+
+    @Test
+    void testLargerTree() {
+        // Tree with 10 nodes
+        int[][] edges = {{0, 1}, {0, 2}, {1, 3}, {1, 4}, {2, 5}, {2, 6}, {3, 7}, {4, 8}, {5, 9}};
+        CentroidDecomposition.CentroidTree tree = CentroidDecomposition.buildFromEdges(10, edges);
+
+        assertEquals(10, tree.size());
+        int root = tree.getRoot();
+        assertTrue(root >= 0 && root < 10);
+        assertEquals(-1, tree.getParent(root));
+
+        // Verify centroid tree structure is valid
+        for (int i = 0; i < 10; i++) {
+            if (i != root) {
+                assertTrue(tree.getParent(i) >= -1 && tree.getParent(i) < 10);
+            }
+        }
+    }
+
+    @Test
+    void testPathGraph() {
+        // Path graph with 8 nodes: 0-1-2-3-4-5-6-7
+        int[][] edges = {{0, 1}, {1, 2}, {2, 3}, {3, 4}, {4, 5}, {5, 6}, {6, 7}};
+        CentroidDecomposition.CentroidTree tree = CentroidDecomposition.buildFromEdges(8, edges);
+
+        assertEquals(8, tree.size());
+        // For path of 8 nodes, centroid should be around middle
+        int root = tree.getRoot();
+        assertTrue(root >= 2 && root <= 5, "Root should be near the middle of path");
+    }
+
+    @Test
+    void testInvalidEmptyTree() {
+        assertThrows(IllegalArgumentException.class, () -> { CentroidDecomposition.buildFromEdges(0, new int[][] {}); });
+    }
+
+    @Test
+    void testInvalidNegativeNodes() {
+        assertThrows(IllegalArgumentException.class, () -> { CentroidDecomposition.buildFromEdges(-1, new int[][] {}); });
+    }
+
+    @Test
+    void testInvalidNullEdges() {
+        assertThrows(IllegalArgumentException.class, () -> { CentroidDecomposition.buildFromEdges(5, null); });
+    }
+
+    @Test
+    void testInvalidEdgeCount() {
+        // Tree with n nodes must have n-1 edges
+        int[][] edges = {{0, 1}, {1, 2}}; // 2 edges for 5 nodes (should be 4)
+        assertThrows(IllegalArgumentException.class, () -> { CentroidDecomposition.buildFromEdges(5, edges); });
+    }
+
+    @Test
+    void testInvalidEdgeFormat() {
+        int[][] edges = {{0, 1, 2}}; // Edge with 3 elements instead of 2
+        assertThrows(IllegalArgumentException.class, () -> { CentroidDecomposition.buildFromEdges(3, edges); });
+    }
+
+    @Test
+    void testInvalidNodeInEdge() {
+        int[][] edges = {{0, 5}}; // Node 5 doesn't exist in tree of size 3
+        assertThrows(IllegalArgumentException.class, () -> { CentroidDecomposition.buildFromEdges(3, edges); });
+    }
+
+    @Test
+    void testInvalidNodeQuery() {
+        int[][] edges = {{0, 1}, {1, 2}};
+        CentroidDecomposition.CentroidTree tree = CentroidDecomposition.buildFromEdges(3, edges);
+
+        assertThrows(IllegalArgumentException.class, () -> { tree.getParent(-1); });
+
+        assertThrows(IllegalArgumentException.class, () -> { tree.getParent(5); });
+    }
+
+    @Test
+    void testToString() {
+        int[][] edges = {{0, 1}, {1, 2}};
+        CentroidDecomposition.CentroidTree tree = CentroidDecomposition.buildFromEdges(3, edges);
+
+        String result = tree.toString();
+        assertNotNull(result);
+        assertTrue(result.contains("Centroid Tree"));
+        assertTrue(result.contains("Node"));
+        assertTrue(result.contains("ROOT"));
+    }
+
+    @Test
+    void testAdjacencyListConstructor() {
+        List<List<Integer>> adj = new ArrayList<>();
+        for (int i = 0; i < 3; i++) {
+            adj.add(new ArrayList<>());
+        }
+        adj.get(0).add(1);
+        adj.get(1).add(0);
+        adj.get(1).add(2);
+        adj.get(2).add(1);
+
+        CentroidDecomposition.CentroidTree tree = new CentroidDecomposition.CentroidTree(adj);
+        assertEquals(3, tree.size());
+        assertEquals(1, tree.getRoot());
+    }
+
+    @Test
+    void testNullAdjacencyList() {
+        assertThrows(IllegalArgumentException.class, () -> { new CentroidDecomposition.CentroidTree(null); });
+    }
+
+    @Test
+    void testEmptyAdjacencyList() {
+        assertThrows(IllegalArgumentException.class, () -> { new CentroidDecomposition.CentroidTree(new ArrayList<>()); });
+    }
+}

From f693c44b539508cd262374a6d8e9d7329301d6cc Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Date: Sat, 22 Nov 2025 18:26:16 +0100
Subject: [PATCH 1111/1338] fix: prevent duplicate auth header in GitHub
 Actions workflow (#7091)

---
 .github/workflows/update-directorymd.yml | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index f6c91abe0e74..101d82427e38 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -1,4 +1,4 @@
-name: Generate Directory Markdown
+name: Generate Directory Markdown
 
 on:
   push:
@@ -15,6 +15,8 @@ jobs:
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v6
+        with:
+          persist-credentials: false
 
       - name: Run Directory Tree Generator
         uses: DenizAltunkapan/directory-tree-generator@v2

From 1c6026ecc640b26d21bf5386872ef99de3d42c60 Mon Sep 17 00:00:00 2001
From: Eswar Venkata Ram Charan Seeram <seerameswar0@gmail.com>
Date: Tue, 25 Nov 2025 01:46:16 +0530
Subject: [PATCH 1112/1338] fix: correct error message in surfaceAreaCylinder
 method (#7106)

---
 src/main/java/com/thealgorithms/maths/Area.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/maths/Area.java b/src/main/java/com/thealgorithms/maths/Area.java
index a34ad6b01ab5..1eba6666dde3 100644
--- a/src/main/java/com/thealgorithms/maths/Area.java
+++ b/src/main/java/com/thealgorithms/maths/Area.java
@@ -96,7 +96,7 @@ public static double surfaceAreaCylinder(final double radius, final double heigh
             throw new IllegalArgumentException(POSITIVE_RADIUS);
         }
         if (height <= 0) {
-            throw new IllegalArgumentException(POSITIVE_RADIUS);
+            throw new IllegalArgumentException(POSITIVE_HEIGHT);
         }
         return 2 * (Math.PI * radius * radius + Math.PI * radius * height);
     }

From 2c4bf3c7c88b2f3b7bfa6baeebb7b569e0530a5a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 25 Nov 2025 16:36:37 +0100
Subject: [PATCH 1113/1338] chore(deps): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.8.1 to 4.9.8.2 (#7109)

chore(deps): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.8.1 to 4.9.8.2.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.8.1...spotbugs-maven-plugin-4.9.8.2)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.8.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 774db2ec4403..eb2aafc0fcc0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -119,7 +119,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.8.1</version>
+                <version>4.9.8.2</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From a14e1e37669f0d8841e4a5bae07726da21e64736 Mon Sep 17 00:00:00 2001
From: prasanth-30011 <prasanthreddypadala121@gmail.com>
Date: Wed, 26 Nov 2025 16:51:07 +0530
Subject: [PATCH 1114/1338] docs: improve javadoc for Combination class (#7126)

Updated class documentation to reflect that the class finds combinations instead of permutations.
---
 src/main/java/com/thealgorithms/backtracking/Combination.java | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/Combination.java b/src/main/java/com/thealgorithms/backtracking/Combination.java
index ecaf7428f986..377d2c862d54 100644
--- a/src/main/java/com/thealgorithms/backtracking/Combination.java
+++ b/src/main/java/com/thealgorithms/backtracking/Combination.java
@@ -7,8 +7,7 @@
 import java.util.TreeSet;
 
 /**
- * Finds all permutations of given array
- * @author Alan Piao (<a href="https://github.com/cpiao3">git-Alan Piao</a>)
+ * Finds all combinations of a given array using backtracking algorithm * @author Alan Piao (<a href="https://github.com/cpiao3">git-Alan Piao</a>)
  */
 public final class Combination {
     private Combination() {

From e841d73837c17d462e8bdfbb4d601e6744082981 Mon Sep 17 00:00:00 2001
From: Jayana Anjani Pavan Vardhan Naidu <vardhannaidu17@gmail.com>
Date: Thu, 27 Nov 2025 16:55:52 +0530
Subject: [PATCH 1115/1338] Update Javadoc for perimeterIrregularPolygon method
 (#7141)

Fixed incorrect @return description in perimeterIrregularPolygon method javadoc. Changed "trapezoid" to "irregular polygon" to accurately reflect what the method calculates.
---
 src/main/java/com/thealgorithms/maths/Perimeter.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/maths/Perimeter.java b/src/main/java/com/thealgorithms/maths/Perimeter.java
index f8aa1876d388..670851eb346b 100644
--- a/src/main/java/com/thealgorithms/maths/Perimeter.java
+++ b/src/main/java/com/thealgorithms/maths/Perimeter.java
@@ -27,7 +27,7 @@ public static float perimeterRegularPolygon(int n, float side) {
      * @param side2 for length of side 2
      * @param side3 for length of side 3
      * @param sides for length of remaining sides
-     * @return Perimeter of given trapezoid.
+     * @return Perimeter of given irregular polygon.
      */
     public static float perimeterIrregularPolygon(float side1, float side2, float side3, float... sides) {
         float perimeter = side1 + side2 + side3;

From d1ea3069203b5d2a132f2cf553424fbf4c2e3353 Mon Sep 17 00:00:00 2001
From: Gokul45-45 <2400032465@kluniversity.in>
Date: Thu, 27 Nov 2025 16:59:48 +0530
Subject: [PATCH 1116/1338] feat: add Valid Parentheses algorithm using Stack
 (#7117)

* feat: add Valid Parentheses algorithm using Stack

* fix: add missing ValidParentheses.java implementation

* fix: remove trailing spaces and add newline at EOF

* fix: remove misplaced ValidParentheses.java from root
---
 .../stacks/ValidParentheses.java              | 74 +++++++++++++++++++
 .../stacks/ValidParenthesesTest.java          | 32 ++++++++
 2 files changed, 106 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/ValidParentheses.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/ValidParenthesesTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/ValidParentheses.java b/src/main/java/com/thealgorithms/stacks/ValidParentheses.java
new file mode 100644
index 000000000000..2cc616a38826
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/ValidParentheses.java
@@ -0,0 +1,74 @@
+package com.thealgorithms.stacks;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Stack;
+
+/**
+ * Valid Parentheses Problem
+ *
+ * Given a string containing just the characters '(', ')', '{', '}', '[' and ']',
+ * determine if the input string is valid.
+ *
+ * An input string is valid if:
+ * 1. Open brackets must be closed by the same type of brackets.
+ * 2. Open brackets must be closed in the correct order.
+ * 3. Every close bracket has a corresponding open bracket of the same type.
+ *
+ * Examples:
+ * Input: "()"
+ * Output: true
+ *
+ * Input: "()[]{}"
+ * Output: true
+ *
+ * Input: "(]"
+ * Output: false
+ *
+ * Input: "([)]"
+ * Output: false
+ *
+ * @author Gokul45-45
+ */
+public final class ValidParentheses {
+    private ValidParentheses() {
+    }
+
+    /**
+     * Checks if the given string has valid parentheses
+     *
+     * @param s the input string containing parentheses
+     * @return true if valid, false otherwise
+     */
+    public static boolean isValid(String s) {
+        if (s == null || s.length() % 2 != 0) {
+            return false;
+        }
+
+        Map<Character, Character> parenthesesMap = new HashMap<>();
+        parenthesesMap.put('(', ')');
+        parenthesesMap.put('{', '}');
+        parenthesesMap.put('[', ']');
+
+        Stack<Character> stack = new Stack<>();
+
+        for (char c : s.toCharArray()) {
+            if (parenthesesMap.containsKey(c)) {
+                // Opening bracket - push to stack
+                stack.push(c);
+            } else {
+                // Closing bracket - check if it matches
+                if (stack.isEmpty()) {
+                    return false;
+                }
+                char openBracket = stack.pop();
+                if (parenthesesMap.get(openBracket) != c) {
+                    return false;
+                }
+            }
+        }
+
+        // Stack should be empty if all brackets are matched
+        return stack.isEmpty();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/ValidParenthesesTest.java b/src/test/java/com/thealgorithms/stacks/ValidParenthesesTest.java
new file mode 100644
index 000000000000..39014780caa9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/ValidParenthesesTest.java
@@ -0,0 +1,32 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class ValidParenthesesTest {
+
+    @Test
+    void testValidParentheses() {
+        assertTrue(ValidParentheses.isValid("()"));
+        assertTrue(ValidParentheses.isValid("()[]{}"));
+        assertTrue(ValidParentheses.isValid("{[]}"));
+        assertTrue(ValidParentheses.isValid(""));
+    }
+
+    @Test
+    void testInvalidParentheses() {
+        assertFalse(ValidParentheses.isValid("(]"));
+        assertFalse(ValidParentheses.isValid("([)]"));
+        assertFalse(ValidParentheses.isValid("{{{"));
+        assertFalse(ValidParentheses.isValid("}"));
+        assertFalse(ValidParentheses.isValid("("));
+    }
+
+    @Test
+    void testNullAndOddLength() {
+        assertFalse(ValidParentheses.isValid(null));
+        assertFalse(ValidParentheses.isValid("(()"));
+    }
+}

From f352f8111ba3fdcc87674263c0907f9452f5b0b2 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 28 Nov 2025 09:26:07 +0100
Subject: [PATCH 1117/1338] chore(deps): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.7.0 to 7.7.1 (#7144)

chore(deps): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.7.0 to 7.7.1.
- [Commits](https://github.com/mebigfatguy/fb-contrib/commits)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.7.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index eb2aafc0fcc0..6b918cdad5bb 100644
--- a/pom.xml
+++ b/pom.xml
@@ -127,7 +127,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.7.0</version>
+                            <version>7.7.1</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

From 4c5525a2e0a9b18b879d774398d1a0f5ca29c509 Mon Sep 17 00:00:00 2001
From: Sameer Prajapati <sameerprajapati066@gmail.com>
Date: Fri, 28 Nov 2025 14:17:53 +0530
Subject: [PATCH 1118/1338] =?UTF-8?q?feat:=20Added=20Gomory=E2=80=93Hu=20T?=
 =?UTF-8?q?ree=20(all-pairs=20min-cuts=20via=20n1=20max-flows)=20(#6818)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Add Gomory–Hu Tree (all-pairs min-cuts via n1 max-flows)

* Stabilize Monte Carlo integration with antithetic variates to reduce variance

* Fix Checkstyle in GomoryHuTreeTest: remove inner assignments, add braces, split declarations

* SpotBugs: use RandomGenerator interface in test helper

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 DIRECTORY.md                                  |   1 +
 .../com/thealgorithms/graph/GomoryHuTree.java | 144 ++++++++++++++++++
 .../randomized/MonteCarloIntegration.java     |  16 +-
 .../thealgorithms/graph/GomoryHuTreeTest.java | 132 ++++++++++++++++
 4 files changed, 289 insertions(+), 4 deletions(-)
 create mode 100644 src/main/java/com/thealgorithms/graph/GomoryHuTree.java
 create mode 100644 src/test/java/com/thealgorithms/graph/GomoryHuTreeTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 042efa72addc..b8db96ffa993 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -385,6 +385,7 @@
           - 📄 [Dinic](src/main/java/com/thealgorithms/graph/Dinic.java)
           - 📄 [Edmonds](src/main/java/com/thealgorithms/graph/Edmonds.java)
           - 📄 [EdmondsKarp](src/main/java/com/thealgorithms/graph/EdmondsKarp.java)
+          - 📄 [GomoryHuTree](src/main/java/com/thealgorithms/graph/GomoryHuTree.java)
           - 📄 [HierholzerAlgorithm](src/main/java/com/thealgorithms/graph/HierholzerAlgorithm.java)
           - 📄 [HierholzerEulerianPath](src/main/java/com/thealgorithms/graph/HierholzerEulerianPath.java)
           - 📄 [HopcroftKarp](src/main/java/com/thealgorithms/graph/HopcroftKarp.java)
diff --git a/src/main/java/com/thealgorithms/graph/GomoryHuTree.java b/src/main/java/com/thealgorithms/graph/GomoryHuTree.java
new file mode 100644
index 000000000000..f8c110f25571
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/GomoryHuTree.java
@@ -0,0 +1,144 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.Queue;
+
+/**
+ * Gomory–Hu tree construction for undirected graphs via n−1 max-flow computations.
+ *
+ * <p>API: {@code buildTree(int[][])} returns {@code {parent, weight}} arrays for the tree.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Gomory%E2%80%93Hu_tree">Wikipedia: Gomory–Hu tree</a>
+ */
+
+public final class GomoryHuTree {
+    private GomoryHuTree() {
+    }
+
+    public static int[][] buildTree(int[][] cap) {
+        validateCapacityMatrix(cap);
+        final int n = cap.length;
+        if (n == 1) {
+            return new int[][] {new int[] {-1}, new int[] {0}};
+        }
+
+        int[] parent = new int[n];
+        int[] weight = new int[n];
+        Arrays.fill(parent, 0);
+        parent[0] = -1;
+        weight[0] = 0;
+
+        for (int s = 1; s < n; s++) {
+            int t = parent[s];
+            MaxFlowResult res = edmondsKarpWithMinCut(cap, s, t);
+            int f = res.flow;
+            weight[s] = f;
+
+            for (int v = 0; v < n; v++) {
+                if (v != s && parent[v] == t && res.reachable[v]) {
+                    parent[v] = s;
+                }
+            }
+
+            if (t != 0 && res.reachable[parent[t]]) {
+                parent[s] = parent[t];
+                parent[t] = s;
+                weight[s] = weight[t];
+                weight[t] = f;
+            }
+        }
+        return new int[][] {parent, weight};
+    }
+
+    private static void validateCapacityMatrix(int[][] cap) {
+        if (cap == null || cap.length == 0) {
+            throw new IllegalArgumentException("Capacity matrix must not be null or empty");
+        }
+        final int n = cap.length;
+        for (int i = 0; i < n; i++) {
+            if (cap[i] == null || cap[i].length != n) {
+                throw new IllegalArgumentException("Capacity matrix must be square");
+            }
+            for (int j = 0; j < n; j++) {
+                if (cap[i][j] < 0) {
+                    throw new IllegalArgumentException("Capacities must be non-negative");
+                }
+            }
+        }
+    }
+
+    private static final class MaxFlowResult {
+        final int flow;
+        final boolean[] reachable;
+        MaxFlowResult(int flow, boolean[] reachable) {
+            this.flow = flow;
+            this.reachable = reachable;
+        }
+    }
+
+    private static MaxFlowResult edmondsKarpWithMinCut(int[][] capacity, int source, int sink) {
+        final int n = capacity.length;
+        int[][] residual = new int[n][n];
+        for (int i = 0; i < n; i++) {
+            residual[i] = Arrays.copyOf(capacity[i], n);
+        }
+
+        int[] parent = new int[n];
+        int maxFlow = 0;
+
+        while (bfs(residual, source, sink, parent)) {
+            int pathFlow = Integer.MAX_VALUE;
+            for (int v = sink; v != source; v = parent[v]) {
+                int u = parent[v];
+                pathFlow = Math.min(pathFlow, residual[u][v]);
+            }
+            for (int v = sink; v != source; v = parent[v]) {
+                int u = parent[v];
+                residual[u][v] -= pathFlow;
+                residual[v][u] += pathFlow;
+            }
+            maxFlow += pathFlow;
+        }
+
+        boolean[] reachable = new boolean[n];
+        markReachable(residual, source, reachable);
+        return new MaxFlowResult(maxFlow, reachable);
+    }
+
+    private static boolean bfs(int[][] residual, int source, int sink, int[] parent) {
+        Arrays.fill(parent, -1);
+        parent[source] = source;
+        Queue<Integer> q = new ArrayDeque<>();
+        q.add(source);
+        while (!q.isEmpty()) {
+            int u = q.poll();
+            for (int v = 0; v < residual.length; v++) {
+                if (residual[u][v] > 0 && parent[v] == -1) {
+                    parent[v] = u;
+                    if (v == sink) {
+                        return true;
+                    }
+                    q.add(v);
+                }
+            }
+        }
+        return false;
+    }
+
+    private static void markReachable(int[][] residual, int source, boolean[] vis) {
+        Arrays.fill(vis, false);
+        Queue<Integer> q = new ArrayDeque<>();
+        vis[source] = true;
+        q.add(source);
+        while (!q.isEmpty()) {
+            int u = q.poll();
+            for (int v = 0; v < residual.length; v++) {
+                if (!vis[v] && residual[u][v] > 0) {
+                    vis[v] = true;
+                    q.add(v);
+                }
+            }
+        }
+    }
+}
diff --git a/src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java b/src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java
index 05d7abbbcd6c..06101295e880 100644
--- a/src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java
+++ b/src/main/java/com/thealgorithms/randomized/MonteCarloIntegration.java
@@ -64,13 +64,21 @@ private static double doApproximate(Function<Double, Double> fx, double a, doubl
         if (!validate(fx, a, b, n)) {
             throw new IllegalArgumentException("Invalid input parameters");
         }
-        double totalArea = 0.0;
+        double total = 0.0;
         double interval = b - a;
-        for (int i = 0; i < n; i++) {
+        int pairs = n / 2;
+        for (int i = 0; i < pairs; i++) {
+            double u = generator.nextDouble();
+            double x1 = a + u * interval;
+            double x2 = a + (1.0 - u) * interval;
+            total += fx.apply(x1);
+            total += fx.apply(x2);
+        }
+        if ((n & 1) == 1) {
             double x = a + generator.nextDouble() * interval;
-            totalArea += fx.apply(x);
+            total += fx.apply(x);
         }
-        return interval * totalArea / n;
+        return interval * total / n;
     }
 
     private static boolean validate(Function<Double, Double> fx, double a, double b, int n) {
diff --git a/src/test/java/com/thealgorithms/graph/GomoryHuTreeTest.java b/src/test/java/com/thealgorithms/graph/GomoryHuTreeTest.java
new file mode 100644
index 000000000000..241f23c0fa1d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/GomoryHuTreeTest.java
@@ -0,0 +1,132 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Queue;
+import java.util.Random;
+import java.util.random.RandomGenerator;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class GomoryHuTreeTest {
+
+    @Test
+    @DisplayName("Single node graph")
+    void singleNode() {
+        int[][] cap = {{0}};
+        int[][] res = GomoryHuTree.buildTree(cap);
+        int[] parent = res[0];
+        int[] weight = res[1];
+        assertEquals(-1, parent[0]);
+        assertEquals(0, weight[0]);
+    }
+
+    @Test
+    @DisplayName("Triangle undirected graph with known min-cuts")
+    void triangleGraph() {
+        // 0-1:3, 1-2:2, 0-2:4
+        int[][] cap = new int[3][3];
+        cap[0][1] = 3;
+        cap[1][0] = 3;
+        cap[1][2] = 2;
+        cap[2][1] = 2;
+        cap[0][2] = 4;
+        cap[2][0] = 4;
+
+        int[][] tree = GomoryHuTree.buildTree(cap);
+        // validate all pairs via path-min-edge equals maxflow
+        validateAllPairs(cap, tree);
+    }
+
+    @Test
+    @DisplayName("Random small undirected graphs compare to EdmondsKarp")
+    void randomSmallGraphs() {
+        Random rng = new Random(42);
+        for (int n = 2; n <= 6; n++) {
+            for (int iter = 0; iter < 10; iter++) {
+                int[][] cap = randSymmetricMatrix(n, 0, 5, rng);
+                int[][] tree = GomoryHuTree.buildTree(cap);
+                validateAllPairs(cap, tree);
+            }
+        }
+    }
+
+    private static int[][] randSymmetricMatrix(int n, int lo, int hi, RandomGenerator rng) {
+        int[][] a = new int[n][n];
+        for (int i = 0; i < n; i++) {
+            for (int j = i + 1; j < n; j++) {
+                int w = rng.nextInt(hi - lo + 1) + lo;
+                a[i][j] = w;
+                a[j][i] = w;
+            }
+        }
+        // zero diagonal
+        for (int i = 0; i < n; i++) {
+            a[i][i] = 0;
+        }
+        return a;
+    }
+
+    private static void validateAllPairs(int[][] cap, int[][] tree) {
+        int n = cap.length;
+        int[] parent = tree[0];
+        int[] weight = tree[1];
+
+        // build adjacency list of tree without generic array creation
+        List<List<int[]>> g = new ArrayList<>();
+        for (int i = 0; i < n; i++) {
+            g.add(new ArrayList<>());
+        }
+        for (int v = 1; v < n; v++) {
+            int u = parent[v];
+            int w = weight[v];
+            g.get(u).add(new int[] {v, w});
+            g.get(v).add(new int[] {u, w});
+        }
+
+        for (int s = 0; s < n; s++) {
+            for (int t = s + 1; t < n; t++) {
+                int treeVal = minEdgeOnPath(g, s, t);
+                int flowVal = EdmondsKarp.maxFlow(cap, s, t);
+                assertEquals(flowVal, treeVal, "pair (" + s + "," + t + ")");
+            }
+        }
+    }
+
+    private static int minEdgeOnPath(List<List<int[]>> g, int s, int t) {
+        // BFS to record parent and edge weight along the path, since it's a tree, unique path exists
+        int n = g.size();
+        int[] parent = new int[n];
+        int[] edgeW = new int[n];
+        Arrays.fill(parent, -1);
+        Queue<Integer> q = new ArrayDeque<>();
+        q.add(s);
+        parent[s] = s;
+        while (!q.isEmpty()) {
+            int u = q.poll();
+            if (u == t) {
+                break;
+            }
+            for (int[] e : g.get(u)) {
+                int v = e[0];
+                int w = e[1];
+                if (parent[v] == -1) {
+                    parent[v] = u;
+                    edgeW[v] = w;
+                    q.add(v);
+                }
+            }
+        }
+        int cur = t;
+        int ans = Integer.MAX_VALUE;
+        while (cur != s) {
+            ans = Math.min(ans, edgeW[cur]);
+            cur = parent[cur];
+        }
+        return ans == Integer.MAX_VALUE ? 0 : ans;
+    }
+}

From a9ba87c4b6efc77f8444fdc94de26af3c6f67df2 Mon Sep 17 00:00:00 2001
From: Taranjeet Singh Kalsi <taranjeetkalsi15@gmail.com>
Date: Fri, 28 Nov 2025 14:21:28 +0530
Subject: [PATCH 1119/1338] Added program to check Abundant number (#6961)

added program for abundant number
---
 .../thealgorithms/maths/AbundantNumber.java   | 58 +++++++++++++++++++
 .../maths/AbundantNumberTest.java             | 31 ++++++++++
 2 files changed, 89 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/AbundantNumber.java
 create mode 100644 src/test/java/com/thealgorithms/maths/AbundantNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/AbundantNumber.java b/src/main/java/com/thealgorithms/maths/AbundantNumber.java
new file mode 100644
index 000000000000..804ac4d71477
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/AbundantNumber.java
@@ -0,0 +1,58 @@
+package com.thealgorithms.maths;
+
+/**
+ * In number theory, an abundant number or excessive number is a positive integer for which
+ * the sum of its proper divisors is greater than the number.
+ * Equivalently, it is a number for which the sum of proper divisors (or aliquot sum) is greater than n.
+ *
+ * The integer 12 is the first abundant number. Its proper divisors are 1, 2, 3, 4 and 6 for a total of 16.
+ *
+ * Wiki: https://en.wikipedia.org/wiki/Abundant_number
+ */
+public final class AbundantNumber {
+
+    private AbundantNumber() {
+    }
+
+    // Function to calculate sum of all divisors including n
+    private static int sumOfDivisors(int n) {
+        int sum = 1 + n; // 1 and n are always divisors
+        for (int i = 2; i <= n / 2; i++) {
+            if (n % i == 0) {
+                sum += i; // adding divisor to sum
+            }
+        }
+        return sum;
+    }
+
+    // Common validation method
+    private static void validatePositiveNumber(int number) {
+        if (number <= 0) {
+            throw new IllegalArgumentException("Number must be positive.");
+        }
+    }
+
+    /**
+     * Check if {@code number} is an Abundant number or not by checking sum of divisors > 2n
+     *
+     * @param number the number
+     * @return {@code true} if {@code number} is an Abundant number, otherwise false
+     */
+    public static boolean isAbundant(int number) {
+        validatePositiveNumber(number);
+
+        return sumOfDivisors(number) > 2 * number;
+    }
+
+    /**
+     * Check if {@code number} is an Abundant number or not by checking Aliquot Sum > n
+     *
+     * @param number the number
+     * @return {@code true} if {@code number} is a Abundant number, otherwise false
+     */
+    public static boolean isAbundantNumber(int number) {
+        validatePositiveNumber(number);
+
+        return AliquotSum.getAliquotSum(number) > number;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/AbundantNumberTest.java b/src/test/java/com/thealgorithms/maths/AbundantNumberTest.java
new file mode 100644
index 000000000000..5b35345afd02
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/AbundantNumberTest.java
@@ -0,0 +1,31 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class AbundantNumberTest {
+    @ParameterizedTest
+    @CsvSource({"12", "66", "222", "444", "888", "2424"})
+    void abundantNumbersTest(int n) {
+        assertTrue(AbundantNumber.isAbundant(n));
+        assertTrue(AbundantNumber.isAbundantNumber(n));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"1", "2", "6", "111", "333", "2222"})
+    void nonAbundantNumbersTest(int n) {
+        assertFalse(AbundantNumber.isAbundant(n));
+        assertFalse(AbundantNumber.isAbundantNumber(n));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"0", "-1"})
+    void throwsNegativeNumbersNotAllowed(int n) {
+        assertThrows(IllegalArgumentException.class, () -> AbundantNumber.isAbundant(n));
+        assertThrows(IllegalArgumentException.class, () -> AbundantNumber.isAbundantNumber(n));
+    }
+}

From ac6fef19dc1a689f8e16a8a7361d1868c2c69e83 Mon Sep 17 00:00:00 2001
From: Taranjeet Singh Kalsi <taranjeetkalsi15@gmail.com>
Date: Mon, 1 Dec 2025 04:07:41 +0530
Subject: [PATCH 1120/1338] Added program to check either number is Evil or
 Odious (#6958)

added program for evil number
---
 .../com/thealgorithms/maths/EvilNumber.java   | 39 +++++++++++++++++++
 .../thealgorithms/maths/EvilNumberTest.java   | 28 +++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/EvilNumber.java
 create mode 100644 src/test/java/com/thealgorithms/maths/EvilNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/EvilNumber.java b/src/main/java/com/thealgorithms/maths/EvilNumber.java
new file mode 100644
index 000000000000..419133702fd4
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/EvilNumber.java
@@ -0,0 +1,39 @@
+package com.thealgorithms.maths;
+
+/**
+ * In number theory, an evil number is a non-negative integer that has an even number of 1s in its binary expansion.
+ * Non-negative integers that are not evil are called odious numbers.
+ *
+ * Evil Number Wiki: https://en.wikipedia.org/wiki/Evil_number
+ * Odious Number Wiki: https://en.wikipedia.org/wiki/Odious_number
+ */
+public final class EvilNumber {
+
+    private EvilNumber() {
+    }
+
+    // Function to count number of one bits in a number using bitwise operators
+    private static int countOneBits(int number) {
+        int oneBitCounter = 0;
+        while (number > 0) {
+            oneBitCounter += number & 1; // increment count if last bit is 1
+            number >>= 1; // right shift to next bit
+        }
+        return oneBitCounter;
+    }
+
+    /**
+     * Check either {@code number} is an Evil number or Odious number
+     *
+     * @param number the number
+     * @return {@code true} if {@code number} is an Evil number, otherwise false (in case of of Odious number)
+     */
+    public static boolean isEvilNumber(int number) {
+        if (number < 0) {
+            throw new IllegalArgumentException("Negative numbers are not allowed.");
+        }
+
+        int noOfOneBits = countOneBits(number);
+        return noOfOneBits % 2 == 0;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/EvilNumberTest.java b/src/test/java/com/thealgorithms/maths/EvilNumberTest.java
new file mode 100644
index 000000000000..e59171fad25f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/EvilNumberTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class EvilNumberTest {
+    @ParameterizedTest
+    @CsvSource({"0", "3", "10", "129", "222", "500", "777", "1198"})
+    void evilNumbersTest(int n) {
+        assertTrue(EvilNumber.isEvilNumber(n));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"1", "7", "100", "333", "555", "1199"})
+    void odiousNumbersTest(int n) {
+        assertFalse(EvilNumber.isEvilNumber(n));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"-1"})
+    void throwsNegativeNumbersNotAllowed(int n) {
+        assertThrows(IllegalArgumentException.class, () -> EvilNumber.isEvilNumber(n));
+    }
+}

From 14c0b0844e747e3c4a9b84e8a63b6db3f6f0294d Mon Sep 17 00:00:00 2001
From: Shewale Gopal Sanjay <shewalegopal4119@gmail.com>
Date: Tue, 2 Dec 2025 01:43:14 +0530
Subject: [PATCH 1121/1338] Added threaded binary tree (#6995)

* Add One-Time Pad Cipher implementation in Java

* Add One-Time Pad Cipher implementation (fixed)

* Add ThreadedBinaryTree with in-order traversal and tests

* feat: add threaded binary tree implementation and tests

* fix: remove redundant null check for SpotBugs compliance
---
 .../trees/ThreadedBinaryTree.java             | 145 ++++++++++++++++++
 .../trees/ThreadedBinaryTreeTest.java         |  50 ++++++
 2 files changed, 195 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/trees/ThreadedBinaryTree.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/ThreadedBinaryTreeTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/ThreadedBinaryTree.java b/src/main/java/com/thealgorithms/datastructures/trees/ThreadedBinaryTree.java
new file mode 100644
index 000000000000..fd8876cecb70
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/trees/ThreadedBinaryTree.java
@@ -0,0 +1,145 @@
+/*
+ * TheAlgorithms (https://github.com/TheAlgorithms/Java)
+ * Author: Shewale41
+ * This file is licensed under the MIT License.
+ */
+
+package com.thealgorithms.datastructures.trees;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Threaded binary tree implementation that supports insertion and
+ * in-order traversal without recursion or stack by using threads.
+ *
+ * <p>In this implementation, a node's null left/right pointers are used
+ * to point to the in-order predecessor/successor respectively. Two flags
+ * indicate whether left/right pointers are real children or threads.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Threaded_binary_tree">Wikipedia:
+ * Threaded binary tree</a>
+ */
+public final class ThreadedBinaryTree {
+
+    private Node root;
+
+    private static final class Node {
+        int value;
+        Node left;
+        Node right;
+        boolean leftIsThread;
+        boolean rightIsThread;
+
+        Node(int value) {
+            this.value = value;
+            this.left = null;
+            this.right = null;
+            this.leftIsThread = false;
+            this.rightIsThread = false;
+        }
+    }
+
+    public ThreadedBinaryTree() {
+        this.root = null;
+    }
+
+    /**
+     * Inserts a value into the threaded binary tree. Duplicate values are inserted
+     * to the right subtree (consistent deterministic rule).
+     *
+     * @param value the integer value to insert
+     */
+    public void insert(int value) {
+        Node newNode = new Node(value);
+        if (root == null) {
+            root = newNode;
+            return;
+        }
+
+        Node current = root;
+        Node parent = null;
+
+        while (true) {
+            parent = current;
+            if (value < current.value) {
+                if (!current.leftIsThread && current.left != null) {
+                    current = current.left;
+                } else {
+                    break;
+                }
+            } else { // value >= current.value
+                if (!current.rightIsThread && current.right != null) {
+                    current = current.right;
+                } else {
+                    break;
+                }
+            }
+        }
+
+        if (value < parent.value) {
+            // attach newNode as left child
+            newNode.left = parent.left;
+            newNode.leftIsThread = parent.leftIsThread;
+            newNode.right = parent;
+            newNode.rightIsThread = true;
+
+            parent.left = newNode;
+            parent.leftIsThread = false;
+        } else {
+            // attach newNode as right child
+            newNode.right = parent.right;
+            newNode.rightIsThread = parent.rightIsThread;
+            newNode.left = parent;
+            newNode.leftIsThread = true;
+
+            parent.right = newNode;
+            parent.rightIsThread = false;
+        }
+    }
+
+    /**
+     * Returns the in-order traversal of the tree as a list of integers.
+     * Traversal is done without recursion or an explicit stack by following threads.
+     *
+     * @return list containing the in-order sequence of node values
+     */
+    public List<Integer> inorderTraversal() {
+        List<Integer> result = new ArrayList<>();
+        Node current = root;
+        if (current == null) {
+            return result;
+        }
+
+        // Move to the leftmost node
+        while (current.left != null && !current.leftIsThread) {
+            current = current.left;
+        }
+
+        while (current != null) {
+            result.add(current.value);
+
+            // If right pointer is a thread, follow it
+            if (current.rightIsThread) {
+                current = current.right;
+            } else {
+                // Move to leftmost node in right subtree
+                current = current.right;
+                while (current != null && !current.leftIsThread && current.left != null) {
+                    current = current.left;
+                }
+            }
+        }
+
+        return result;
+    }
+
+    /**
+     * Helper: checks whether the tree is empty.
+     *
+     * @return true if tree has no nodes
+     */
+    public boolean isEmpty() {
+        return root == null;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/ThreadedBinaryTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/ThreadedBinaryTreeTest.java
new file mode 100644
index 000000000000..c5973168438e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/ThreadedBinaryTreeTest.java
@@ -0,0 +1,50 @@
+/*
+ * TheAlgorithms (https://github.com/TheAlgorithms/Java)
+ * Author: Shewale41
+ * This file is licensed under the MIT License.
+ */
+
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Basic tests for ThreadedBinaryTree inorder traversal.
+ */
+public class ThreadedBinaryTreeTest {
+
+    @Test
+    public void testInorderTraversalSimple() {
+        ThreadedBinaryTree tree = new ThreadedBinaryTree();
+        tree.insert(50);
+        tree.insert(30);
+        tree.insert(70);
+        tree.insert(20);
+        tree.insert(40);
+        tree.insert(60);
+        tree.insert(80);
+
+        List<Integer> expected = List.of(20, 30, 40, 50, 60, 70, 80);
+        List<Integer> actual = tree.inorderTraversal();
+
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testInorderWithDuplicates() {
+        ThreadedBinaryTree tree = new ThreadedBinaryTree();
+        tree.insert(5);
+        tree.insert(3);
+        tree.insert(7);
+        tree.insert(7); // duplicate
+        tree.insert(2);
+
+        List<Integer> expected = List.of(2, 3, 5, 7, 7);
+        List<Integer> actual = tree.inorderTraversal();
+
+        assertEquals(expected, actual);
+    }
+}

From 8d2cdb27db3b0979d28bbb2a723fa2e235a736b2 Mon Sep 17 00:00:00 2001
From: duvvuvenkataramana <venkataramana2048@gmail.com>
Date: Tue, 2 Dec 2025 01:47:32 +0530
Subject: [PATCH 1122/1338] feat: implement One-Time Pad cipher (#6941) (#7096)

* feat: implement One-Time Pad cipher (#6941)

* style: format OneTimePadCipher with clang-format
---
 .../ciphers/OneTimePadCipher.java             | 89 +++++++++++++++++++
 .../ciphers/OneTimePadCipherTest.java         | 49 ++++++++++
 2 files changed, 138 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/OneTimePadCipher.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/OneTimePadCipherTest.java

diff --git a/src/main/java/com/thealgorithms/ciphers/OneTimePadCipher.java b/src/main/java/com/thealgorithms/ciphers/OneTimePadCipher.java
new file mode 100644
index 000000000000..7733f5cb46f2
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/OneTimePadCipher.java
@@ -0,0 +1,89 @@
+package com.thealgorithms.ciphers;
+
+import java.security.SecureRandom;
+import java.util.Objects;
+
+/**
+ * One-Time Pad (OTP) cipher implementation.
+ *
+ * <p>The One-Time Pad is information-theoretically secure if:
+ * <ul>
+ *   <li>The key is truly random.</li>
+ *   <li>The key length is at least as long as the plaintext.</li>
+ *   <li>The key is used only once and kept secret.</li>
+ * </ul>
+ *
+ * <p>This implementation is for <b>educational purposes only</b> and should not be
+ * used in production systems.
+ */
+public final class OneTimePadCipher {
+
+    private static final SecureRandom RANDOM = new SecureRandom();
+
+    private OneTimePadCipher() {
+        // utility class
+    }
+
+    /**
+     * Generates a random key of the given length in bytes.
+     *
+     * @param length the length of the key in bytes, must be non-negative
+     * @return a new random key
+     * @throws IllegalArgumentException if length is negative
+     */
+    public static byte[] generateKey(int length) {
+        if (length < 0) {
+            throw new IllegalArgumentException("length must be non-negative");
+        }
+        byte[] key = new byte[length];
+        RANDOM.nextBytes(key);
+        return key;
+    }
+
+    /**
+     * Encrypts the given plaintext bytes using the provided key.
+     * <p>The key length must be exactly the same as the plaintext length.
+     *
+     * @param plaintext the plaintext bytes, must not be {@code null}
+     * @param key the one-time pad key bytes, must not be {@code null}
+     * @return the ciphertext bytes
+     * @throws IllegalArgumentException if the key length does not match plaintext length
+     * @throws NullPointerException if plaintext or key is {@code null}
+     */
+    public static byte[] encrypt(byte[] plaintext, byte[] key) {
+        validateInputs(plaintext, key);
+        return xor(plaintext, key);
+    }
+
+    /**
+     * Decrypts the given ciphertext bytes using the provided key.
+     * <p>For a One-Time Pad, decryption is identical to encryption:
+     * {@code plaintext = ciphertext XOR key}.
+     *
+     * @param ciphertext the ciphertext bytes, must not be {@code null}
+     * @param key the one-time pad key bytes, must not be {@code null}
+     * @return the decrypted plaintext bytes
+     * @throws IllegalArgumentException if the key length does not match ciphertext length
+     * @throws NullPointerException if ciphertext or key is {@code null}
+     */
+    public static byte[] decrypt(byte[] ciphertext, byte[] key) {
+        validateInputs(ciphertext, key);
+        return xor(ciphertext, key);
+    }
+
+    private static void validateInputs(byte[] input, byte[] key) {
+        Objects.requireNonNull(input, "input must not be null");
+        Objects.requireNonNull(key, "key must not be null");
+        if (input.length != key.length) {
+            throw new IllegalArgumentException("Key length must match input length");
+        }
+    }
+
+    private static byte[] xor(byte[] data, byte[] key) {
+        byte[] result = new byte[data.length];
+        for (int i = 0; i < data.length; i++) {
+            result[i] = (byte) (data[i] ^ key[i]);
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/OneTimePadCipherTest.java b/src/test/java/com/thealgorithms/ciphers/OneTimePadCipherTest.java
new file mode 100644
index 000000000000..837c56c603d4
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/OneTimePadCipherTest.java
@@ -0,0 +1,49 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.nio.charset.StandardCharsets;
+import org.junit.jupiter.api.Test;
+
+class OneTimePadCipherTest {
+
+    @Test
+    void encryptAndDecryptWithRandomKeyRestoresPlaintext() {
+        String plaintext = "The quick brown fox jumps over the lazy dog.";
+        byte[] plaintextBytes = plaintext.getBytes(StandardCharsets.UTF_8);
+
+        byte[] key = OneTimePadCipher.generateKey(plaintextBytes.length);
+
+        byte[] ciphertext = OneTimePadCipher.encrypt(plaintextBytes, key);
+        byte[] decrypted = OneTimePadCipher.decrypt(ciphertext, key);
+
+        assertArrayEquals(plaintextBytes, decrypted);
+        assertEquals(plaintext, new String(decrypted, StandardCharsets.UTF_8));
+    }
+
+    @Test
+    void generateKeyWithNegativeLengthThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> OneTimePadCipher.generateKey(-1));
+    }
+
+    @Test
+    void encryptWithMismatchedKeyLengthThrowsException() {
+        byte[] data = "hello".getBytes(StandardCharsets.UTF_8);
+        byte[] shortKey = OneTimePadCipher.generateKey(2);
+
+        assertThrows(IllegalArgumentException.class, () -> OneTimePadCipher.encrypt(data, shortKey));
+    }
+
+    @Test
+    void decryptWithMismatchedKeyLengthThrowsException() {
+        byte[] data = "hello".getBytes(StandardCharsets.UTF_8);
+        byte[] key = OneTimePadCipher.generateKey(data.length);
+        byte[] ciphertext = OneTimePadCipher.encrypt(data, key);
+
+        byte[] wrongSizedKey = OneTimePadCipher.generateKey(data.length + 1);
+
+        assertThrows(IllegalArgumentException.class, () -> OneTimePadCipher.decrypt(ciphertext, wrongSizedKey));
+    }
+}

From 927fe1f87cdfe2ea57051812427e78c9cf6f4775 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 2 Dec 2025 09:54:59 +0100
Subject: [PATCH 1123/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 12.1.2 to 12.2.0 (#7147)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 12.1.2 to 12.2.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-12.1.2...checkstyle-12.2.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 12.2.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 6b918cdad5bb..dc7d211b2742 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>12.1.2</version>
+                    <version>12.2.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From bd7f269aa992e87359d82b3d3d289b4fefde5eea Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 2 Dec 2025 08:58:42 +0000
Subject: [PATCH 1124/1338] chore(deps): bump gitpod/workspace-java-21 from
 2025-10-06-13-14-25 to 2025-11-14-10-05-32 (#7148)

chore(deps): bump gitpod/workspace-java-21

Bumps gitpod/workspace-java-21 from 2025-10-06-13-14-25 to 2025-11-14-10-05-32.

---
updated-dependencies:
- dependency-name: gitpod/workspace-java-21
  dependency-version: 2025-11-14-10-05-32
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .gitpod.dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitpod.dockerfile b/.gitpod.dockerfile
index 4195f928d1bc..a8951da7de26 100644
--- a/.gitpod.dockerfile
+++ b/.gitpod.dockerfile
@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2025-10-06-13-14-25
+FROM gitpod/workspace-java-21:2025-11-14-10-05-32
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

From 246162e5bdc6b9f4eb4cf8287e31eb44c36301da Mon Sep 17 00:00:00 2001
From: espinosadev <163946778+espinosa-dev@users.noreply.github.com>
Date: Fri, 5 Dec 2025 16:45:25 +0100
Subject: [PATCH 1125/1338] Fixed redundant boolean logic (#7151)

---
 .../java/com/thealgorithms/strings/Upper.java  | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/Upper.java b/src/main/java/com/thealgorithms/strings/Upper.java
index 5e248cb6ee39..85db7d41e1aa 100644
--- a/src/main/java/com/thealgorithms/strings/Upper.java
+++ b/src/main/java/com/thealgorithms/strings/Upper.java
@@ -15,23 +15,27 @@ public static void main(String[] args) {
     }
 
     /**
-     * Converts all the characters in this {@code String} to upper case
+     * Converts all the characters in this {@code String} to upper case.
      *
      * @param s the string to convert
      * @return the {@code String}, converted to uppercase.
      */
     public static String toUpperCase(String s) {
         if (s == null) {
-            throw new IllegalArgumentException("Input string connot be null");
+            throw new IllegalArgumentException("Input string cannot be null");
         }
         if (s.isEmpty()) {
             return s;
         }
-        StringBuilder result = new StringBuilder(s);
-        for (int i = 0; i < result.length(); ++i) {
-            char currentChar = result.charAt(i);
-            if (Character.isLetter(currentChar) && Character.isLowerCase(currentChar)) {
-                result.setCharAt(i, Character.toUpperCase(currentChar));
+
+        StringBuilder result = new StringBuilder(s.length());
+
+        for (int i = 0; i < s.length(); ++i) {
+            char currentChar = s.charAt(i);
+            if (Character.isLowerCase(currentChar)) {
+                result.append(Character.toUpperCase(currentChar));
+            } else {
+                result.append(currentChar);
             }
         }
         return result.toString();

From 316def4ea65f68ca8982148b97896c8bfef27e87 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20S=C3=A1nchez=20N=C3=BA=C3=B1ez?=
 <dsannue@upv.edu.es>
Date: Sun, 7 Dec 2025 12:18:55 +0100
Subject: [PATCH 1126/1338] Add Snell's Law refraction algorithm (#7150)

* Add Snell's Law implementation for refraction angle

* Add tests for Snell's Law calculations

* Update documentation with reference link to Snell's Law

Added a reference link to Snell's Law in the documentation.

* Prevent instantiation of SnellLaw class

Make SnellLaw class non-instantiable by adding a private constructor.

* Rename SnellsLawTest to SnellLawTest

* Refactor SnellLawTest for clarity and accuracy

* Rename SnellsLaw.java to SnellLaw.java

* Refactor SnellLawTest with additional assertions

* Refactor SnellLaw class constructor and error handling

Refactor SnellLaw constructor and error message formatting.

* Fix missing newline at end of SnellLawTest.java

Ensure that the SnellLawTest class has a newline at the end of the file.

* Simplify assertions in SnellLawTest

* Simplify exception throwing for total internal reflection
---
 .../com/thealgorithms/physics/SnellLaw.java   | 33 +++++++++++++++
 .../thealgorithms/physics/SnellLawTest.java   | 41 +++++++++++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/physics/SnellLaw.java
 create mode 100644 src/test/java/com/thealgorithms/physics/SnellLawTest.java

diff --git a/src/main/java/com/thealgorithms/physics/SnellLaw.java b/src/main/java/com/thealgorithms/physics/SnellLaw.java
new file mode 100644
index 000000000000..2736984814fd
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/SnellLaw.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.physics;
+
+/**
+ * Calculates refraction angle using Snell's Law:
+ * n1 * sin(theta1) = n2 * sin(theta2)
+ * @see <a href="https://en.wikipedia.org/wiki/Snell%27s_law">Snell's Law</a>
+ */
+public final class SnellLaw {
+
+    private SnellLaw() {
+        throw new AssertionError("No instances.");
+    }
+
+    /**
+     * Computes the refracted angle (theta2) in radians.
+     *
+     * @param n1 index of refraction of medium 1
+     * @param n2 index of refraction of medium 2
+     * @param theta1 incident angle in radians
+     * @return refracted angle (theta2) in radians
+     * @throws IllegalArgumentException if total internal reflection occurs
+     */
+    public static double refractedAngle(double n1, double n2, double theta1) {
+        double ratio = n1 / n2;
+        double sinTheta2 = ratio * Math.sin(theta1);
+
+        if (Math.abs(sinTheta2) > 1.0) {
+            throw new IllegalArgumentException("Total internal reflection: no refraction possible.");
+        }
+
+        return Math.asin(sinTheta2);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/SnellLawTest.java b/src/test/java/com/thealgorithms/physics/SnellLawTest.java
new file mode 100644
index 000000000000..ddd5fb1d5af7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/SnellLawTest.java
@@ -0,0 +1,41 @@
+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class SnellLawTest {
+
+    @Test
+    public void testRefractedAngle() {
+        double n1 = 1.0; // air
+        double n2 = 1.5; // glass
+        double theta1 = Math.toRadians(30);
+
+        double theta2 = SnellLaw.refractedAngle(n1, n2, theta1);
+
+        double expected = Math.asin(n1 / n2 * Math.sin(theta1));
+
+        assertEquals(expected, theta2, 1e-12);
+    }
+
+    @Test
+    public void testTotalInternalReflection() {
+        double n1 = 1.5;
+        double n2 = 1.0;
+        double theta1 = Math.toRadians(60); // large angle
+
+        assertThrows(IllegalArgumentException.class, () -> SnellLaw.refractedAngle(n1, n2, theta1));
+    }
+
+    @Test
+    public void testNoTotalInternalReflectionAtLowAngles() {
+        double n1 = 1.5;
+        double n2 = 1.0;
+        double theta1 = Math.toRadians(10);
+
+        assertDoesNotThrow(() -> SnellLaw.refractedAngle(n1, n2, theta1));
+    }
+}

From e7c3e1f7739a494d96ded480b167b28ca657f1cc Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 9 Dec 2025 09:43:17 +0100
Subject: [PATCH 1127/1338] chore(deps): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.7.1 to 7.7.2 (#7153)

chore(deps): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.7.1 to 7.7.2.
- [Commits](https://github.com/mebigfatguy/fb-contrib/commits/v7.7.2)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.7.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index dc7d211b2742..4baf7a5f99b0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -127,7 +127,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.7.1</version>
+                            <version>7.7.2</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

From 520151ab8e51b502e96cd959ebdfdfff7468aa22 Mon Sep 17 00:00:00 2001
From: codeahl <142953446+codeahl@users.noreply.github.com>
Date: Wed, 10 Dec 2025 03:00:28 -0600
Subject: [PATCH 1128/1338] Add Big-O time and space complexity comments for
 sorting algorithms (#7155)

Add time and space complexity comments for specific sorting algorithms

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../com/thealgorithms/sorts/BubbleSort.java    |  7 +++++++
 .../java/com/thealgorithms/sorts/HeapSort.java | 13 ++++++++++++-
 .../com/thealgorithms/sorts/InsertionSort.java | 18 ++++++++++++++++++
 .../com/thealgorithms/sorts/MergeSort.java     | 13 +++++++++----
 .../com/thealgorithms/sorts/QuickSort.java     | 11 +++++++++--
 .../com/thealgorithms/sorts/SelectionSort.java | 13 +++++++++----
 .../thealgorithms/sorts/TopologicalSort.java   | 11 +++++++++--
 7 files changed, 73 insertions(+), 13 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/BubbleSort.java b/src/main/java/com/thealgorithms/sorts/BubbleSort.java
index 6823c68d0a74..d2eca3506c2d 100644
--- a/src/main/java/com/thealgorithms/sorts/BubbleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BubbleSort.java
@@ -10,6 +10,13 @@ class BubbleSort implements SortAlgorithm {
     /**
      * Implements generic bubble sort algorithm.
      *
+     * Time Complexity:
+     * - Best case: O(n) – array is already sorted.
+     * - Average case: O(n^2)
+     * - Worst case: O(n^2)
+     *
+     * Space Complexity: O(1) – in-place sorting.
+     *
      * @param array the array to be sorted.
      * @param <T> the type of elements in the array.
      * @return the sorted array.
diff --git a/src/main/java/com/thealgorithms/sorts/HeapSort.java b/src/main/java/com/thealgorithms/sorts/HeapSort.java
index e798fb91b925..5e3b20f43e10 100644
--- a/src/main/java/com/thealgorithms/sorts/HeapSort.java
+++ b/src/main/java/com/thealgorithms/sorts/HeapSort.java
@@ -1,9 +1,20 @@
 package com.thealgorithms.sorts;
 
 /**
- * Heap Sort Algorithm Implementation
+ * Heap Sort algorithm implementation.
+ *
+ * Heap sort converts the array into a max-heap and repeatedly extracts the maximum
+ * element to sort the array in increasing order.
+ *
+ * Time Complexity:
+ * - Best case: O(n log n)
+ * - Average case: O(n log n)
+ * - Worst case: O(n log n)
+ *
+ * Space Complexity: O(1) – in-place sorting
  *
  * @see <a href="https://en.wikipedia.org/wiki/Heapsort">Heap Sort Algorithm</a>
+ * @see SortAlgorithm
  */
 public class HeapSort implements SortAlgorithm {
 
diff --git a/src/main/java/com/thealgorithms/sorts/InsertionSort.java b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
index 21ebf3827b5f..fdbfd9cd1cfa 100644
--- a/src/main/java/com/thealgorithms/sorts/InsertionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
@@ -1,5 +1,23 @@
 package com.thealgorithms.sorts;
 
+/**
+ * Generic Insertion Sort algorithm.
+ *
+ * Standard insertion sort iterates through the array and inserts each element into its
+ * correct position in the sorted portion of the array.
+ *
+ * Sentinel sort is a variation that first places the minimum element at index 0 to
+ * avoid redundant comparisons in subsequent passes.
+ *
+ * Time Complexity:
+ * - Best case: O(n) – array is already sorted (sentinel sort can improve slightly)
+ * - Average case: O(n^2)
+ * - Worst case: O(n^2) – array is reverse sorted
+ *
+ * Space Complexity: O(1) – in-place sorting
+ *
+ * @see SortAlgorithm
+ */
 class InsertionSort implements SortAlgorithm {
 
     /**
diff --git a/src/main/java/com/thealgorithms/sorts/MergeSort.java b/src/main/java/com/thealgorithms/sorts/MergeSort.java
index 86a184f67b26..f7a7c8da004d 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSort.java
@@ -13,11 +13,16 @@ class MergeSort implements SortAlgorithm {
     private Comparable[] aux;
 
     /**
-     * Generic merge sort algorithm implements.
+     * Generic merge sort algorithm.
      *
-     * @param unsorted the array which should be sorted.
-     * @param <T> Comparable class.
-     * @return sorted array.
+     * Time Complexity:
+     * - Best case: O(n log n)
+     * - Average case: O(n log n)
+     * - Worst case: O(n log n)
+     *
+     * Space Complexity: O(n) – requires auxiliary array for merging.
+     *
+     * @see SortAlgorithm
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] unsorted) {
diff --git a/src/main/java/com/thealgorithms/sorts/QuickSort.java b/src/main/java/com/thealgorithms/sorts/QuickSort.java
index 3abb1aae2306..a025e6909259 100644
--- a/src/main/java/com/thealgorithms/sorts/QuickSort.java
+++ b/src/main/java/com/thealgorithms/sorts/QuickSort.java
@@ -8,9 +8,16 @@
 class QuickSort implements SortAlgorithm {
 
     /**
-     * This method implements the Generic Quick Sort
+     * Generic Quick Sort algorithm.
      *
-     * @param array The array to be sorted Sorts the array in increasing order
+     * Time Complexity:
+     * - Best case: O(n log n) – pivot splits array roughly in half each time.
+     * - Average case: O(n log n)
+     * - Worst case: O(n^2) – occurs when pivot consistently produces unbalanced splits.
+     *
+     * Space Complexity: O(log n) – recursion stack, in-place sorting.
+     *
+     * @see SortAlgorithm
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSort.java b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
index db7732d7e218..2d1814441701 100644
--- a/src/main/java/com/thealgorithms/sorts/SelectionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
@@ -2,11 +2,16 @@
 
 public class SelectionSort implements SortAlgorithm {
     /**
-     * Sorts an array of comparable elements in increasing order using the selection sort algorithm.
+     * Generic Selection Sort algorithm.
      *
-     * @param array the array to be sorted
-     * @param <T> the class of array elements
-     * @return the sorted array
+     * Time Complexity:
+     * - Best case: O(n^2)
+     * - Average case: O(n^2)
+     * - Worst case: O(n^2)
+     *
+     * Space Complexity: O(1) – in-place sorting.
+     *
+     * @see SortAlgorithm
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
diff --git a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
index e4ed240a9947..382ddde9a6f2 100644
--- a/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
+++ b/src/main/java/com/thealgorithms/sorts/TopologicalSort.java
@@ -11,9 +11,16 @@
  * a linked list. A Directed Graph is proven to be acyclic when a DFS or Depth First Search is
  * performed, yielding no back-edges.
  *
- * https://en.wikipedia.org/wiki/Topological_sorting
+ * Time Complexity: O(V + E)
+ *   - V: number of vertices
+ *   - E: number of edges
  *
- * @author Jonathan Taylor (https://github.com/Jtmonument)
+ * Space Complexity: O(V + E)
+ *   - adjacency list and recursion stack in DFS
+ *
+ * Reference: https://en.wikipedia.org/wiki/Topological_sorting
+ *
+ * Author: Jonathan Taylor (https://github.com/Jtmonument)
  * Based on Introduction to Algorithms 3rd Edition
  */
 public final class TopologicalSort {

From 4f40206684b026f8c0315d8fa419f4951e0500ba Mon Sep 17 00:00:00 2001
From: Lucas Horn <146038502+LucasAHorn@users.noreply.github.com>
Date: Wed, 10 Dec 2025 03:04:32 -0600
Subject: [PATCH 1129/1338] Add unit tests for graph algorithms (#7133) (#7156)

* Add unit tests for graph algorithms (BFS, DFS, Dijkstra, Bellman-Ford) #7133

- Created BellmanFordTest.java with 10 test methods covering various graph scenarios

- Created ConnectedComponentTest.java with 15 test methods for DFS-based component counting

- Enhanced MatrixGraphsTest.java with additional BFS/DFS test cases

- Enhanced DijkstraAlgorithmTest.java with comprehensive shortest path tests

Fixes #7133

* fix: format files using clang

* fix: removing my changes on pull_request_template

---------

Co-authored-by: prashantdubeypng <vinoddubey6059@gmail.com>
---
 .../graphs/BellmanFordTest.java               | 158 +++++++++++++
 .../graphs/ConnectedComponentTest.java        | 204 +++++++++++++++++
 .../graphs/DijkstraAlgorithmTest.java         | 117 ++++++++++
 .../graphs/MatrixGraphsTest.java              | 211 ++++++++++++++++++
 4 files changed, 690 insertions(+)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/BellmanFordTest.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/ConnectedComponentTest.java

diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/BellmanFordTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/BellmanFordTest.java
new file mode 100644
index 000000000000..c824241c680d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/BellmanFordTest.java
@@ -0,0 +1,158 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the BellmanFord algorithm implementation.
+ * Tests cover various graph scenarios including:
+ * - Simple weighted graphs
+ * - Graphs with negative weights
+ * - Single vertex graphs
+ * - Disconnected graphs
+ * - Linear path graphs
+ */
+class BellmanFordTest {
+
+    @Test
+    void testSimpleGraph() {
+        // Create a simple graph with 5 vertices and 8 edges
+        // Graph visualization:
+        // 1
+        // /|\
+        // 6 | 7
+        // / | \
+        // 0 5 2
+        // \ | /
+        // 8 | -2
+        // \|/
+        // 4---3
+        // 9
+        BellmanFord bellmanFord = new BellmanFord(5, 8);
+        bellmanFord.addEdge(0, 1, 6);
+        bellmanFord.addEdge(0, 4, 8);
+        bellmanFord.addEdge(1, 2, 7);
+        bellmanFord.addEdge(1, 4, 5);
+        bellmanFord.addEdge(2, 3, -2);
+        bellmanFord.addEdge(2, 4, -3);
+        bellmanFord.addEdge(3, 4, 9);
+        bellmanFord.addEdge(4, 3, 7);
+
+        // Verify edge array creation
+        assertNotNull(bellmanFord.getEdgeArray());
+        assertEquals(8, bellmanFord.getEdgeArray().length);
+    }
+
+    @Test
+    void testGraphWithNegativeWeights() {
+        // Graph with negative edge weights (but no negative cycle)
+        BellmanFord bellmanFord = new BellmanFord(4, 5);
+        bellmanFord.addEdge(0, 1, 4);
+        bellmanFord.addEdge(0, 2, 5);
+        bellmanFord.addEdge(1, 2, -3);
+        bellmanFord.addEdge(2, 3, 4);
+        bellmanFord.addEdge(1, 3, 6);
+
+        assertNotNull(bellmanFord.getEdgeArray());
+        assertEquals(5, bellmanFord.getEdgeArray().length);
+    }
+
+    @Test
+    void testSingleVertexGraph() {
+        // Graph with single vertex and no edges
+        BellmanFord bellmanFord = new BellmanFord(1, 0);
+        assertNotNull(bellmanFord.getEdgeArray());
+        assertEquals(0, bellmanFord.getEdgeArray().length);
+    }
+
+    @Test
+    void testLinearGraph() {
+        // Linear graph: 0 -> 1 -> 2 -> 3
+        BellmanFord bellmanFord = new BellmanFord(4, 3);
+        bellmanFord.addEdge(0, 1, 2);
+        bellmanFord.addEdge(1, 2, 3);
+        bellmanFord.addEdge(2, 3, 4);
+
+        assertNotNull(bellmanFord.getEdgeArray());
+        assertEquals(3, bellmanFord.getEdgeArray().length);
+    }
+
+    @Test
+    void testEdgeAddition() {
+        BellmanFord bellmanFord = new BellmanFord(3, 3);
+
+        bellmanFord.addEdge(0, 1, 5);
+        bellmanFord.addEdge(1, 2, 3);
+        bellmanFord.addEdge(0, 2, 10);
+
+        // Verify all edges were added
+        assertNotNull(bellmanFord.getEdgeArray());
+        assertEquals(3, bellmanFord.getEdgeArray().length);
+    }
+
+    @Test
+    void testGraphWithZeroWeightEdges() {
+        // Graph with zero weight edges
+        BellmanFord bellmanFord = new BellmanFord(3, 3);
+        bellmanFord.addEdge(0, 1, 0);
+        bellmanFord.addEdge(1, 2, 0);
+        bellmanFord.addEdge(0, 2, 1);
+
+        assertNotNull(bellmanFord.getEdgeArray());
+        assertEquals(3, bellmanFord.getEdgeArray().length);
+    }
+
+    @Test
+    void testLargerGraph() {
+        // Larger graph with 6 vertices
+        BellmanFord bellmanFord = new BellmanFord(6, 9);
+        bellmanFord.addEdge(0, 1, 5);
+        bellmanFord.addEdge(0, 2, 3);
+        bellmanFord.addEdge(1, 3, 6);
+        bellmanFord.addEdge(1, 2, 2);
+        bellmanFord.addEdge(2, 4, 4);
+        bellmanFord.addEdge(2, 5, 2);
+        bellmanFord.addEdge(2, 3, 7);
+        bellmanFord.addEdge(3, 4, -1);
+        bellmanFord.addEdge(4, 5, -2);
+
+        assertNotNull(bellmanFord.getEdgeArray());
+        assertEquals(9, bellmanFord.getEdgeArray().length);
+    }
+
+    @Test
+    void testVertexAndEdgeCount() {
+        BellmanFord bellmanFord = new BellmanFord(10, 15);
+        assertEquals(10, bellmanFord.vertex);
+        assertEquals(15, bellmanFord.edge);
+    }
+
+    @Test
+    void testMultipleEdgesBetweenSameVertices() {
+        // Graph allowing multiple edges between same vertices
+        BellmanFord bellmanFord = new BellmanFord(2, 3);
+        bellmanFord.addEdge(0, 1, 5);
+        bellmanFord.addEdge(0, 1, 3);
+        bellmanFord.addEdge(1, 0, 2);
+
+        assertNotNull(bellmanFord.getEdgeArray());
+        assertEquals(3, bellmanFord.getEdgeArray().length);
+    }
+
+    @Test
+    void testCompleteGraph() {
+        // Complete graph with 4 vertices (6 edges for undirected equivalent)
+        BellmanFord bellmanFord = new BellmanFord(4, 6);
+        bellmanFord.addEdge(0, 1, 1);
+        bellmanFord.addEdge(0, 2, 2);
+        bellmanFord.addEdge(0, 3, 3);
+        bellmanFord.addEdge(1, 2, 4);
+        bellmanFord.addEdge(1, 3, 5);
+        bellmanFord.addEdge(2, 3, 6);
+
+        assertNotNull(bellmanFord.getEdgeArray());
+        assertEquals(6, bellmanFord.getEdgeArray().length);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/ConnectedComponentTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/ConnectedComponentTest.java
new file mode 100644
index 000000000000..b5cfdd9de04f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/ConnectedComponentTest.java
@@ -0,0 +1,204 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the Graph class in ConnectedComponent.java.
+ * Tests the depth-first search implementation and connected component counting.
+ * Covers various graph topologies including:
+ * - Single connected components
+ * - Multiple disconnected components
+ * - Self-loops
+ * - Linear chains
+ * - Cyclic graphs
+ */
+class ConnectedComponentTest {
+
+    @Test
+    void testSingleConnectedComponent() {
+        Graph<Integer> graph = new Graph<>();
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 4);
+        graph.addEdge(4, 1);
+
+        assertEquals(1, graph.countGraphs());
+    }
+
+    @Test
+    void testTwoDisconnectedComponents() {
+        Graph<Integer> graph = new Graph<>();
+        // Component 1: 1-2-3
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+        // Component 2: 4-5
+        graph.addEdge(4, 5);
+
+        assertEquals(2, graph.countGraphs());
+    }
+
+    @Test
+    void testThreeDisconnectedComponents() {
+        Graph<Character> graph = new Graph<>();
+        // Component 1: a-b-c-d-e
+        graph.addEdge('a', 'b');
+        graph.addEdge('a', 'e');
+        graph.addEdge('b', 'e');
+        graph.addEdge('b', 'c');
+        graph.addEdge('c', 'd');
+        graph.addEdge('d', 'a');
+        // Component 2: x-y-z
+        graph.addEdge('x', 'y');
+        graph.addEdge('x', 'z');
+        // Component 3: w (self-loop)
+        graph.addEdge('w', 'w');
+
+        assertEquals(3, graph.countGraphs());
+    }
+
+    @Test
+    void testSingleNodeSelfLoop() {
+        Graph<Integer> graph = new Graph<>();
+        graph.addEdge(1, 1);
+
+        assertEquals(1, graph.countGraphs());
+    }
+
+    @Test
+    void testLinearChain() {
+        Graph<Integer> graph = new Graph<>();
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 4);
+        graph.addEdge(4, 5);
+
+        assertEquals(1, graph.countGraphs());
+    }
+
+    @Test
+    void testStarTopology() {
+        // Star graph with center node 0 connected to nodes 1, 2, 3, 4
+        Graph<Integer> graph = new Graph<>();
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 2);
+        graph.addEdge(0, 3);
+        graph.addEdge(0, 4);
+
+        assertEquals(1, graph.countGraphs());
+    }
+
+    @Test
+    void testCompleteGraph() {
+        // Complete graph K4: every node connected to every other node
+        Graph<Integer> graph = new Graph<>();
+        graph.addEdge(1, 2);
+        graph.addEdge(1, 3);
+        graph.addEdge(1, 4);
+        graph.addEdge(2, 3);
+        graph.addEdge(2, 4);
+        graph.addEdge(3, 4);
+
+        assertEquals(1, graph.countGraphs());
+    }
+
+    @Test
+    void testStringVertices() {
+        Graph<String> graph = new Graph<>();
+        // Component 1
+        graph.addEdge("New York", "Los Angeles");
+        graph.addEdge("Los Angeles", "Chicago");
+        // Component 2
+        graph.addEdge("London", "Paris");
+        // Component 3
+        graph.addEdge("Tokyo", "Tokyo");
+
+        assertEquals(3, graph.countGraphs());
+    }
+
+    @Test
+    void testEmptyGraph() {
+        Graph<Integer> graph = new Graph<>();
+        assertEquals(0, graph.countGraphs());
+    }
+
+    @Test
+    void testDepthFirstSearchBasic() {
+        Graph<Integer> graph = new Graph<>();
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+
+        // Get the first node and perform DFS
+        assertNotNull(graph.nodeList);
+        assertEquals(3, graph.nodeList.size());
+    }
+
+    @Test
+    void testManyIsolatedComponents() {
+        Graph<Integer> graph = new Graph<>();
+        // Create 5 isolated components (each is a self-loop)
+        graph.addEdge(1, 1);
+        graph.addEdge(2, 2);
+        graph.addEdge(3, 3);
+        graph.addEdge(4, 4);
+        graph.addEdge(5, 5);
+
+        assertEquals(5, graph.countGraphs());
+    }
+
+    @Test
+    void testBidirectionalEdges() {
+        Graph<Integer> graph = new Graph<>();
+        // Note: This is a directed graph representation
+        // Adding edge 1->2 does not automatically add 2->1
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 1);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 2);
+
+        assertEquals(1, graph.countGraphs());
+    }
+
+    @Test
+    void testCyclicGraph() {
+        Graph<Integer> graph = new Graph<>();
+        // Create a cycle: 1 -> 2 -> 3 -> 4 -> 1
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 4);
+        graph.addEdge(4, 1);
+
+        assertEquals(1, graph.countGraphs());
+    }
+
+    @Test
+    void testMultipleCycles() {
+        Graph<Integer> graph = new Graph<>();
+        // Cycle 1: 1 -> 2 -> 3 -> 1
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 1);
+        // Cycle 2: 4 -> 5 -> 4
+        graph.addEdge(4, 5);
+        graph.addEdge(5, 4);
+
+        assertEquals(2, graph.countGraphs());
+    }
+
+    @Test
+    void testIntegerGraphFromMainExample() {
+        // Recreate the example from main method
+        Graph<Integer> graph = new Graph<>();
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+        graph.addEdge(2, 4);
+        graph.addEdge(3, 5);
+        graph.addEdge(7, 8);
+        graph.addEdge(8, 10);
+        graph.addEdge(10, 8);
+
+        assertEquals(2, graph.countGraphs());
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java
index c5df9acdf33b..a189091c17d3 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.graphs;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.BeforeEach;
@@ -61,4 +62,120 @@ void testInvalidSourceVertex() {
         assertThrows(IllegalArgumentException.class, () -> dijkstraAlgorithm.run(graph, -1));
         assertThrows(IllegalArgumentException.class, () -> dijkstraAlgorithm.run(graph, graph.length));
     }
+
+    @Test
+    void testLinearGraph() {
+        // Linear graph: 0 - 1 - 2 - 3
+        // with weights: 2 3 4
+        int[][] linearGraph = {{0, 2, 0, 0}, {2, 0, 3, 0}, {0, 3, 0, 4}, {0, 0, 4, 0}};
+
+        DijkstraAlgorithm dijkstraLinear = new DijkstraAlgorithm(4);
+        int[] distances = dijkstraLinear.run(linearGraph, 0);
+
+        assertArrayEquals(new int[] {0, 2, 5, 9}, distances);
+    }
+
+    @Test
+    void testStarTopology() {
+        // Star graph: center node 0 connected to all others
+        // 1(2)
+        // |
+        // 3(4)-0-2(3)
+        // |
+        // 4(5)
+        int[][] starGraph = {{0, 2, 3, 4, 5}, {2, 0, 0, 0, 0}, {3, 0, 0, 0, 0}, {4, 0, 0, 0, 0}, {5, 0, 0, 0, 0}};
+
+        DijkstraAlgorithm dijkstraStar = new DijkstraAlgorithm(5);
+        int[] distances = dijkstraStar.run(starGraph, 0);
+
+        assertArrayEquals(new int[] {0, 2, 3, 4, 5}, distances);
+    }
+
+    @Test
+    void testCompleteGraphK4() {
+        // Complete graph K4 with varying weights
+        int[][] completeGraph = {{0, 1, 2, 3}, {1, 0, 4, 5}, {2, 4, 0, 6}, {3, 5, 6, 0}};
+
+        DijkstraAlgorithm dijkstraComplete = new DijkstraAlgorithm(4);
+        int[] distances = dijkstraComplete.run(completeGraph, 0);
+
+        // Direct paths from 0 are shortest
+        assertArrayEquals(new int[] {0, 1, 2, 3}, distances);
+    }
+
+    @Test
+    void testDifferentSourceVertex() {
+        // Test running from different source vertices
+        int[][] simpleGraph = {{0, 5, 0, 0}, {5, 0, 3, 0}, {0, 3, 0, 2}, {0, 0, 2, 0}};
+
+        DijkstraAlgorithm dijkstra = new DijkstraAlgorithm(4);
+
+        // From vertex 0
+        int[] distFrom0 = dijkstra.run(simpleGraph, 0);
+        assertArrayEquals(new int[] {0, 5, 8, 10}, distFrom0);
+
+        // From vertex 2
+        int[] distFrom2 = dijkstra.run(simpleGraph, 2);
+        assertArrayEquals(new int[] {8, 3, 0, 2}, distFrom2);
+
+        // From vertex 3
+        int[] distFrom3 = dijkstra.run(simpleGraph, 3);
+        assertArrayEquals(new int[] {10, 5, 2, 0}, distFrom3);
+    }
+
+    @Test
+    void testUnitWeightGraph() {
+        // Graph with all unit weights (like BFS distance)
+        int[][] unitGraph = {{0, 1, 1, 0}, {1, 0, 1, 1}, {1, 1, 0, 1}, {0, 1, 1, 0}};
+
+        DijkstraAlgorithm dijkstraUnit = new DijkstraAlgorithm(4);
+        int[] distances = dijkstraUnit.run(unitGraph, 0);
+
+        assertArrayEquals(new int[] {0, 1, 1, 2}, distances);
+    }
+
+    @Test
+    void testTwoVertexGraph() {
+        int[][] twoVertexGraph = {{0, 7}, {7, 0}};
+
+        DijkstraAlgorithm dijkstraTwo = new DijkstraAlgorithm(2);
+        int[] distances = dijkstraTwo.run(twoVertexGraph, 0);
+
+        assertArrayEquals(new int[] {0, 7}, distances);
+    }
+
+    @Test
+    void testShortcutPath() {
+        // Graph where direct path is longer than indirect path
+        // 0 --(10)--> 2
+        // 0 --(1)--> 1 --(2)--> 2
+        int[][] shortcutGraph = {{0, 1, 10}, {1, 0, 2}, {10, 2, 0}};
+
+        DijkstraAlgorithm dijkstraShortcut = new DijkstraAlgorithm(3);
+        int[] distances = dijkstraShortcut.run(shortcutGraph, 0);
+
+        // The shortest path to vertex 2 should be 3 (via vertex 1), not 10 (direct)
+        assertArrayEquals(new int[] {0, 1, 3}, distances);
+    }
+
+    @Test
+    void testSourceToSourceDistanceIsZero() {
+        // Verify distance from source to itself is always 0
+        int[] distances = dijkstraAlgorithm.run(graph, 0);
+        assertEquals(0, distances[0]);
+
+        distances = dijkstraAlgorithm.run(graph, 5);
+        assertEquals(0, distances[5]);
+    }
+
+    @Test
+    void testLargeWeights() {
+        // Graph with large weights
+        int[][] largeWeightGraph = {{0, 1000, 0}, {1000, 0, 2000}, {0, 2000, 0}};
+
+        DijkstraAlgorithm dijkstraLarge = new DijkstraAlgorithm(3);
+        int[] distances = dijkstraLarge.run(largeWeightGraph, 0);
+
+        assertArrayEquals(new int[] {0, 1000, 3000}, distances);
+    }
 }
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java
index cc8a2df872ce..eaff0222bd36 100644
--- a/src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/MatrixGraphsTest.java
@@ -137,4 +137,215 @@ void testDisconnectedGraph() {
         assertTrue(dfs.containsAll(Arrays.asList(0, 1)));
         assertTrue(bfs.containsAll(Arrays.asList(0, 1)));
     }
+
+    @Test
+    void testSingleVertexGraphDfs() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(1);
+
+        List<Integer> dfs = graph.depthFirstOrder(0);
+        assertEquals(1, dfs.size());
+        assertEquals(0, dfs.getFirst());
+    }
+
+    @Test
+    void testSingleVertexGraphBfs() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(1);
+
+        List<Integer> bfs = graph.breadthFirstOrder(0);
+        assertEquals(1, bfs.size());
+        assertEquals(0, bfs.getFirst());
+    }
+
+    @Test
+    void testBfsLevelOrder() {
+        // Create a graph where BFS should visit level by level
+        // 0
+        // /|\
+        // 1 2 3
+        // |
+        // 4
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 2);
+        graph.addEdge(0, 3);
+        graph.addEdge(1, 4);
+
+        List<Integer> bfs = graph.breadthFirstOrder(0);
+        assertEquals(5, bfs.size());
+        assertEquals(0, bfs.get(0));
+        // Level 1 vertices (1, 2, 3) should appear before level 2 vertex (4)
+        int indexOf4 = bfs.indexOf(4);
+        assertTrue(bfs.indexOf(1) < indexOf4);
+        assertTrue(bfs.indexOf(2) < indexOf4);
+        assertTrue(bfs.indexOf(3) < indexOf4);
+    }
+
+    @Test
+    void testDfsStartFromDifferentVertices() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(4);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+
+        // DFS from vertex 0
+        List<Integer> dfs0 = graph.depthFirstOrder(0);
+        assertEquals(4, dfs0.size());
+        assertEquals(0, dfs0.get(0));
+
+        // DFS from vertex 2
+        List<Integer> dfs2 = graph.depthFirstOrder(2);
+        assertEquals(4, dfs2.size());
+        assertEquals(2, dfs2.get(0));
+
+        // DFS from vertex 3
+        List<Integer> dfs3 = graph.depthFirstOrder(3);
+        assertEquals(4, dfs3.size());
+        assertEquals(3, dfs3.get(0));
+    }
+
+    @Test
+    void testBfsStartFromDifferentVertices() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(4);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+
+        // BFS from vertex 0
+        List<Integer> bfs0 = graph.breadthFirstOrder(0);
+        assertEquals(4, bfs0.size());
+        assertEquals(0, bfs0.get(0));
+
+        // BFS from vertex 2
+        List<Integer> bfs2 = graph.breadthFirstOrder(2);
+        assertEquals(4, bfs2.size());
+        assertEquals(2, bfs2.get(0));
+    }
+
+    @Test
+    void testStarTopologyBfs() {
+        // Star graph: 0 is center connected to 1, 2, 3, 4
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 2);
+        graph.addEdge(0, 3);
+        graph.addEdge(0, 4);
+
+        List<Integer> bfs = graph.breadthFirstOrder(0);
+        assertEquals(5, bfs.size());
+        assertEquals(0, bfs.get(0));
+        // All neighbors should be at distance 1
+        assertTrue(bfs.containsAll(Arrays.asList(1, 2, 3, 4)));
+    }
+
+    @Test
+    void testStarTopologyDfs() {
+        // Star graph: 0 is center connected to 1, 2, 3, 4
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 2);
+        graph.addEdge(0, 3);
+        graph.addEdge(0, 4);
+
+        List<Integer> dfs = graph.depthFirstOrder(0);
+        assertEquals(5, dfs.size());
+        assertEquals(0, dfs.get(0));
+        assertTrue(dfs.containsAll(Arrays.asList(1, 2, 3, 4)));
+    }
+
+    @Test
+    void testNegativeStartVertexDfs() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        graph.addEdge(0, 1);
+
+        List<Integer> dfs = graph.depthFirstOrder(-1);
+        assertTrue(dfs.isEmpty());
+    }
+
+    @Test
+    void testNegativeStartVertexBfs() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        graph.addEdge(0, 1);
+
+        List<Integer> bfs = graph.breadthFirstOrder(-1);
+        assertTrue(bfs.isEmpty());
+    }
+
+    @Test
+    void testCompleteGraphKFour() {
+        // Complete graph K4: every vertex connected to every other vertex
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(4);
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 2);
+        graph.addEdge(0, 3);
+        graph.addEdge(1, 2);
+        graph.addEdge(1, 3);
+        graph.addEdge(2, 3);
+
+        assertEquals(6, graph.numberOfEdges());
+
+        List<Integer> dfs = graph.depthFirstOrder(0);
+        List<Integer> bfs = graph.breadthFirstOrder(0);
+
+        assertEquals(4, dfs.size());
+        assertEquals(4, bfs.size());
+        assertTrue(dfs.containsAll(Arrays.asList(0, 1, 2, 3)));
+        assertTrue(bfs.containsAll(Arrays.asList(0, 1, 2, 3)));
+    }
+
+    @Test
+    void testLargerGraphTraversal() {
+        // Create a larger graph with 10 vertices
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(10);
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 2);
+        graph.addEdge(1, 3);
+        graph.addEdge(1, 4);
+        graph.addEdge(2, 5);
+        graph.addEdge(2, 6);
+        graph.addEdge(3, 7);
+        graph.addEdge(4, 8);
+        graph.addEdge(5, 9);
+
+        List<Integer> dfs = graph.depthFirstOrder(0);
+        List<Integer> bfs = graph.breadthFirstOrder(0);
+
+        assertEquals(10, dfs.size());
+        assertEquals(10, bfs.size());
+        assertEquals(0, dfs.get(0));
+        assertEquals(0, bfs.get(0));
+    }
+
+    @Test
+    void testSelfLoop() {
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(3);
+        graph.addEdge(0, 0); // Self loop
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+
+        List<Integer> dfs = graph.depthFirstOrder(0);
+        List<Integer> bfs = graph.breadthFirstOrder(0);
+
+        assertEquals(3, dfs.size());
+        assertEquals(3, bfs.size());
+    }
+
+    @Test
+    void testLinearGraphTraversal() {
+        // Linear graph: 0 - 1 - 2 - 3 - 4
+        AdjacencyMatrixGraph graph = new AdjacencyMatrixGraph(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(1, 2);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 4);
+
+        List<Integer> dfs = graph.depthFirstOrder(0);
+        List<Integer> bfs = graph.breadthFirstOrder(0);
+
+        assertEquals(5, dfs.size());
+        assertEquals(5, bfs.size());
+
+        // In a linear graph, BFS and DFS starting from 0 should be the same
+        assertEquals(Arrays.asList(0, 1, 2, 3, 4), dfs);
+        assertEquals(Arrays.asList(0, 1, 2, 3, 4), bfs);
+    }
 }

From a8bc9cc5258f68ced843b827cbabb1b60e80f35d Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 10 Dec 2025 10:33:35 +0000
Subject: [PATCH 1130/1338] chore(deps-dev): bump org.mockito:mockito-core from
 5.20.0 to 5.21.0 (#7154)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.20.0 to 5.21.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.20.0...v5.21.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.21.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 4baf7a5f99b0..185249a0ea0f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.20.0</version>
+            <version>5.21.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 746457ce152909a76613cdd7ba69b0e7acd72e5b Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 13 Dec 2025 00:29:17 +0100
Subject: [PATCH 1131/1338] chore(deps): bump actions/cache from 4 to 5 in
 /.github/workflows (#7162)

Bumps [actions/cache](https://github.com/actions/cache) from 4 to 5.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](https://github.com/actions/cache/compare/v4...v5)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/infer.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index c85b1d225f72..9d4dcf63000b 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -33,7 +33,7 @@ jobs:
 
       - name: Cache infer build
         id: cache-infer
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: infer
           key: ${{ runner.os }}-infer-${{ env.year_week }}

From bccaf970baf8f7caa7ae08c0088e224625d8d5f0 Mon Sep 17 00:00:00 2001
From: utkarsh patel <153971829+Utkarsh-patel26@users.noreply.github.com>
Date: Sun, 14 Dec 2025 15:38:18 +0530
Subject: [PATCH 1132/1338] Add Z-Algorithm for Linear-Time String Pattern
 Matching (#7124)

* Add Z-Algorithm (string pattern matching) with tests

* Add Z-Algorithm (string pattern matching) with tests

* Add Z-Algorithm (string pattern matching) with tests

* Fix checkstyle errors for ZAlgorithm

* Fix: clang-format and checkstyle compliance for ZAlgorithm
---
 DIRECTORY.md                                  |  2 +
 .../com/thealgorithms/strings/ZAlgorithm.java | 48 +++++++++++++++++++
 .../thealgorithms/strings/ZAlgorithmTest.java | 25 ++++++++++
 3 files changed, 75 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/ZAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/strings/ZAlgorithmTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index b8db96ffa993..6ea83fc6a60a 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -822,6 +822,7 @@
           - 📄 [Upper](src/main/java/com/thealgorithms/strings/Upper.java)
           - 📄 [ValidParentheses](src/main/java/com/thealgorithms/strings/ValidParentheses.java)
           - 📄 [WordLadder](src/main/java/com/thealgorithms/strings/WordLadder.java)
+          - 📄 [ZAlgorithm](src/main/java/com/thealgorithms/strings/ZAlgorithm.java)
           - 📁 **zigZagPattern**
             - 📄 [ZigZagPattern](src/main/java/com/thealgorithms/strings/zigZagPattern/ZigZagPattern.java)
         - 📁 **tree**
@@ -1579,6 +1580,7 @@
           - 📄 [UpperTest](src/test/java/com/thealgorithms/strings/UpperTest.java)
           - 📄 [ValidParenthesesTest](src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java)
           - 📄 [WordLadderTest](src/test/java/com/thealgorithms/strings/WordLadderTest.java)
+          - 📄 [ZAlgorithmTest](src/test/java/com/thealgorithms/strings/ZAlgorithmTest.java)
           - 📁 **zigZagPattern**
             - 📄 [ZigZagPatternTest](src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java)
         - 📁 **tree**
diff --git a/src/main/java/com/thealgorithms/strings/ZAlgorithm.java b/src/main/java/com/thealgorithms/strings/ZAlgorithm.java
new file mode 100644
index 000000000000..dc029b751f45
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/ZAlgorithm.java
@@ -0,0 +1,48 @@
+/*
+ * https://en.wikipedia.org/wiki/Z-algorithm
+ */
+package com.thealgorithms.strings;
+
+public final class ZAlgorithm {
+
+    private ZAlgorithm() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    public static int[] zFunction(String s) {
+        int n = s.length();
+        int[] z = new int[n];
+        int l = 0;
+        int r = 0;
+
+        for (int i = 1; i < n; i++) {
+            if (i <= r) {
+                z[i] = Math.min(r - i + 1, z[i - l]);
+            }
+
+            while (i + z[i] < n && s.charAt(z[i]) == s.charAt(i + z[i])) {
+                z[i]++;
+            }
+
+            if (i + z[i] - 1 > r) {
+                l = i;
+                r = i + z[i] - 1;
+            }
+        }
+
+        return z;
+    }
+
+    public static int search(String text, String pattern) {
+        String s = pattern + "$" + text;
+        int[] z = zFunction(s);
+        int p = pattern.length();
+
+        for (int i = 0; i < z.length; i++) {
+            if (z[i] == p) {
+                return i - p - 1;
+            }
+        }
+        return -1;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/ZAlgorithmTest.java b/src/test/java/com/thealgorithms/strings/ZAlgorithmTest.java
new file mode 100644
index 000000000000..df749ed9a8b5
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/ZAlgorithmTest.java
@@ -0,0 +1,25 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class ZAlgorithmTest {
+
+    @Test
+    void testZFunction() {
+        int[] z = ZAlgorithm.zFunction("aaaaa");
+        assertArrayEquals(new int[] {0, 4, 3, 2, 1}, z);
+    }
+
+    @Test
+    void testSearchFound() {
+        assertEquals(2, ZAlgorithm.search("abcabca", "cab"));
+    }
+
+    @Test
+    void testSearchNotFound() {
+        assertEquals(-1, ZAlgorithm.search("abcdef", "gh"));
+    }
+}

From aa914512030269fd30173cd3892804bac203aded Mon Sep 17 00:00:00 2001
From: Muhammad Junaid Khalid <mjk22071998@gmail.com>
Date: Sun, 14 Dec 2025 15:14:00 +0500
Subject: [PATCH 1133/1338] feat: Binary Tree to String algorithm added
 (Leetcode 606) (#6727)

* feat: BinaryTreeToString.java Added with tests

* fix: javadoc added to BinaryTreeToString

* fix: link to leetcode added
---
 .../trees/BinaryTreeToString.java             | 100 ++++++++++++++++++
 .../trees/BinaryTreeToStringTest.java         |  57 ++++++++++
 2 files changed, 157 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/trees/BinaryTreeToString.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeToStringTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/BinaryTreeToString.java b/src/main/java/com/thealgorithms/datastructures/trees/BinaryTreeToString.java
new file mode 100644
index 000000000000..2f9b3b489d56
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/trees/BinaryTreeToString.java
@@ -0,0 +1,100 @@
+package com.thealgorithms.datastructures.trees;
+
+/**
+ * Leetcode 606: Construct String from Binary Tree:
+ * https://leetcode.com/problems/construct-string-from-binary-tree/
+ *
+ * Utility class to convert a {@link BinaryTree} into its string representation.
+ * <p>
+ * The conversion follows a preorder traversal pattern (root → left → right)
+ * and uses parentheses to denote the tree structure.
+ * Empty parentheses "()" are used to explicitly represent missing left children
+ * when a right child exists, ensuring the structure is unambiguous.
+ * </p>
+ *
+ * <h2>Rules:</h2>
+ * <ul>
+ * <li>Each node is represented as {@code (value)}.</li>
+ * <li>If a node has only a right child, include {@code ()} before the right
+ * child
+ * to indicate the missing left child.</li>
+ * <li>If a node has no children, it appears as just {@code (value)}.</li>
+ * <li>The outermost parentheses are removed from the final string.</li>
+ * </ul>
+ *
+ * <h3>Example:</h3>
+ *
+ * <pre>
+ *     Input tree:
+ *           1
+ *          / \
+ *         2   3
+ *          \
+ *           4
+ *
+ *     Output string:
+ *     "1(2()(4))(3)"
+ * </pre>
+ *
+ * <p>
+ * This implementation matches the logic from LeetCode problem 606:
+ * <i>Construct String from Binary Tree</i>.
+ * </p>
+ *
+ * @author Muhammad Junaid
+ * @see BinaryTree
+ */
+public class BinaryTreeToString {
+
+    /** String builder used to accumulate the string representation. */
+    private StringBuilder sb;
+
+    /**
+     * Converts a binary tree (given its root node) to its string representation.
+     *
+     * @param root the root node of the binary tree
+     * @return the string representation of the binary tree, or an empty string if
+     *         the tree is null
+     */
+    public String tree2str(BinaryTree.Node root) {
+        if (root == null) {
+            return "";
+        }
+
+        sb = new StringBuilder();
+        dfs(root);
+
+        // Remove the leading and trailing parentheses added by the root call
+        return sb.substring(1, sb.length() - 1);
+    }
+
+    /**
+     * Performs a recursive depth-first traversal to build the string.
+     * Each recursive call appends the node value and its children (if any)
+     * enclosed in parentheses.
+     *
+     * @param node the current node being processed
+     */
+    private void dfs(BinaryTree.Node node) {
+        if (node == null) {
+            return;
+        }
+
+        sb.append("(").append(node.data);
+
+        // Recursively build left and right subtrees
+        if (node.left != null) {
+            dfs(node.left);
+        }
+
+        // Handle the special case: right child exists but left child is null
+        if (node.right != null && node.left == null) {
+            sb.append("()");
+            dfs(node.right);
+        } else if (node.right != null) {
+            dfs(node.right);
+        }
+
+        sb.append(")");
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeToStringTest.java b/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeToStringTest.java
new file mode 100644
index 000000000000..2461fd74143d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeToStringTest.java
@@ -0,0 +1,57 @@
+package com.thealgorithms.datastructures.trees;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests for the BinaryTreeToString class.
+ */
+public class BinaryTreeToStringTest {
+
+    @Test
+    public void testTreeToStringBasic() {
+        BinaryTree tree = new BinaryTree();
+        tree.put(1);
+        tree.put(2);
+        tree.put(3);
+        tree.put(4);
+
+        BinaryTreeToString converter = new BinaryTreeToString();
+        String result = converter.tree2str(tree.getRoot());
+
+        // Output will depend on insertion logic of BinaryTree.put()
+        // which is BST-style, so result = "1()(2()(3()(4)))"
+        Assertions.assertEquals("1()(2()(3()(4)))", result);
+    }
+
+    @Test
+    public void testSingleNodeTree() {
+        BinaryTree tree = new BinaryTree();
+        tree.put(10);
+
+        BinaryTreeToString converter = new BinaryTreeToString();
+        String result = converter.tree2str(tree.getRoot());
+
+        Assertions.assertEquals("10", result);
+    }
+
+    @Test
+    public void testComplexTreeStructure() {
+        BinaryTree.Node root = new BinaryTree.Node(10);
+        root.left = new BinaryTree.Node(5);
+        root.right = new BinaryTree.Node(20);
+        root.right.left = new BinaryTree.Node(15);
+        root.right.right = new BinaryTree.Node(25);
+
+        BinaryTreeToString converter = new BinaryTreeToString();
+        String result = converter.tree2str(root);
+
+        Assertions.assertEquals("10(5)(20(15)(25))", result);
+    }
+
+    @Test
+    public void testNullTree() {
+        BinaryTreeToString converter = new BinaryTreeToString();
+        Assertions.assertEquals("", converter.tree2str(null));
+    }
+}

From d9f2ac8340946f4c677a3ea1a5b9128a533086e0 Mon Sep 17 00:00:00 2001
From: Taranjeet Singh Kalsi <taranjeetkalsi15@gmail.com>
Date: Sun, 14 Dec 2025 15:59:14 +0530
Subject: [PATCH 1134/1338] Added program to check Lucky number (#6962)

added program for lucky number
---
 .../com/thealgorithms/maths/LuckyNumber.java  | 78 +++++++++++++++++++
 .../thealgorithms/maths/LuckyNumberTest.java  | 32 ++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/LuckyNumber.java
 create mode 100644 src/test/java/com/thealgorithms/maths/LuckyNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/LuckyNumber.java b/src/main/java/com/thealgorithms/maths/LuckyNumber.java
new file mode 100644
index 000000000000..70308e1e0edd
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/LuckyNumber.java
@@ -0,0 +1,78 @@
+package com.thealgorithms.maths;
+
+/**
+ * In number theory, a lucky number is a natural number in a set which is generated by a certain "sieve".
+ * This sieve is similar to the sieve of Eratosthenes that generates the primes,
+ * but it eliminates numbers based on their position in the remaining set,
+ * instead of their value (or position in the initial set of natural numbers).
+ *
+ * Wiki: https://en.wikipedia.org/wiki/Lucky_number
+ */
+public final class LuckyNumber {
+
+    private LuckyNumber() {
+    }
+
+    // Common validation method
+    private static void validatePositiveNumber(int number) {
+        if (number <= 0) {
+            throw new IllegalArgumentException("Number must be positive.");
+        }
+    }
+
+    // Function to check recursively for Lucky Number
+    private static boolean isLuckyRecursiveApproach(int n, int counter) {
+        // Base case: If counter exceeds n, number is lucky
+        if (counter > n) {
+            return true;
+        }
+
+        // If number is eliminated in this step, it's not lucky
+        if (n % counter == 0) {
+            return false;
+        }
+
+        // Calculate new position after removing every counter-th number
+        int newNumber = n - (n / counter);
+
+        // Recursive call for next round
+        return isLuckyRecursiveApproach(newNumber, counter + 1);
+    }
+
+    /**
+     * Check if {@code number} is a Lucky number or not using recursive approach
+     *
+     * @param number the number
+     * @return {@code true} if {@code number} is a Lucky number, otherwise false
+     */
+    public static boolean isLuckyNumber(int number) {
+        validatePositiveNumber(number);
+        int counterStarting = 2;
+        return isLuckyRecursiveApproach(number, counterStarting);
+    }
+
+    /**
+     * Check if {@code number} is a Lucky number or not using iterative approach
+     *
+     * @param number the number
+     * @return {@code true} if {@code number} is a Lucky number, otherwise false
+     */
+    public static boolean isLucky(int number) {
+        validatePositiveNumber(number);
+
+        int counter = 2; // Position starts from 2 (since first elimination happens at 2)
+        int position = number; // The position of the number in the sequence
+
+        while (counter <= position) {
+            if (position % counter == 0) {
+                return false;
+            } // Number is eliminated
+
+            // Update the position of n after removing every counter-th number
+            position = position - (position / counter);
+            counter++;
+        }
+
+        return true; // Survives all eliminations → Lucky Number
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/LuckyNumberTest.java b/src/test/java/com/thealgorithms/maths/LuckyNumberTest.java
new file mode 100644
index 000000000000..91904316b25c
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/LuckyNumberTest.java
@@ -0,0 +1,32 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class LuckyNumberTest {
+
+    @ParameterizedTest
+    @CsvSource({"1", "3", "13", "49", "109", "459", "949"})
+    void luckyNumbersTest(int n) {
+        assertTrue(LuckyNumber.isLucky(n));
+        assertTrue(LuckyNumber.isLuckyNumber(n));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"2", "17", "100", "300", "700"})
+    void nonLuckyNumbersTest(int n) {
+        assertFalse(LuckyNumber.isLucky(n));
+        assertFalse(LuckyNumber.isLuckyNumber(n));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"0", "-1"})
+    void throwsNegativeNumbersNotAllowed(int n) {
+        assertThrows(IllegalArgumentException.class, () -> LuckyNumber.isLucky(n));
+        assertThrows(IllegalArgumentException.class, () -> LuckyNumber.isLuckyNumber(n));
+    }
+}

From b76962d5ad9b66e13c757b65bf0a8d9843c52505 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 16 Dec 2025 17:53:29 +0100
Subject: [PATCH 1135/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 12.2.0 to 12.3.0 (#7167)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 12.2.0 to 12.3.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-12.2.0...checkstyle-12.3.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 12.3.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 185249a0ea0f..d60f8b9668e6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>12.2.0</version>
+                    <version>12.3.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 4f293b33e553af095305de23d72cf29c416a0c9f Mon Sep 17 00:00:00 2001
From: NYAMATHABAD KOUSHIK SAI <120590127+koushik-sai@users.noreply.github.com>
Date: Wed, 17 Dec 2025 21:18:00 +0530
Subject: [PATCH 1136/1338] [FEAT] Add Thin Lens formula for ray optics (#7170)

* [FEAT] Add Thin Lens formula for ray optics

* [CI] Re-run clang-format checks

* [CI] Re-run checks after rebase

* [STYLE] Apply clang-format to ThinLensTest

---------

Co-authored-by: Koushik Sai <nyamathabadkoushik@gmail.com>
---
 .../com/thealgorithms/physics/ThinLens.java   | 74 +++++++++++++++++++
 .../thealgorithms/physics/ThinLensTest.java   | 19 +++++
 2 files changed, 93 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/physics/ThinLens.java
 create mode 100644 src/test/java/com/thealgorithms/physics/ThinLensTest.java

diff --git a/src/main/java/com/thealgorithms/physics/ThinLens.java b/src/main/java/com/thealgorithms/physics/ThinLens.java
new file mode 100644
index 000000000000..5fb29d8c41e4
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/ThinLens.java
@@ -0,0 +1,74 @@
+package com.thealgorithms.physics;
+
+/**
+ * Implements the Thin Lens Formula used in ray optics:
+ *
+ * <pre>
+ *     1/f = 1/v + 1/u
+ * </pre>
+ *
+ * where:
+ * <ul>
+ *   <li>f = focal length</li>
+ *   <li>u = object distance</li>
+ *   <li>v = image distance</li>
+ * </ul>
+ *
+ * Uses the Cartesian sign convention.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Thin_lens">Thin Lens</a>
+ */
+public final class ThinLens {
+
+    private ThinLens() {
+        throw new AssertionError("No instances.");
+    }
+
+    /**
+     * Computes the image distance using the thin lens formula.
+     *
+     * @param focalLength focal length of the lens (f)
+     * @param objectDistance object distance (u)
+     * @return image distance (v)
+     * @throws IllegalArgumentException if focal length or object distance is zero
+     */
+    public static double imageDistance(double focalLength, double objectDistance) {
+
+        if (focalLength == 0 || objectDistance == 0) {
+            throw new IllegalArgumentException("Focal length and object distance must be non-zero.");
+        }
+
+        return 1.0 / ((1.0 / focalLength) - (1.0 / objectDistance));
+    }
+
+    /**
+     * Computes magnification of the image.
+     *
+     * <pre>
+     *     m = v / u
+     * </pre>
+     *
+     * @param imageDistance image distance (v)
+     * @param objectDistance object distance (u)
+     * @return magnification
+     * @throws IllegalArgumentException if object distance is zero
+     */
+    public static double magnification(double imageDistance, double objectDistance) {
+
+        if (objectDistance == 0) {
+            throw new IllegalArgumentException("Object distance must be non-zero.");
+        }
+
+        return imageDistance / objectDistance;
+    }
+
+    /**
+     * Determines whether the image formed is real or virtual.
+     *
+     * @param imageDistance image distance (v)
+     * @return {@code true} if image is real, {@code false} if virtual
+     */
+    public static boolean isRealImage(double imageDistance) {
+        return imageDistance > 0;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/ThinLensTest.java b/src/test/java/com/thealgorithms/physics/ThinLensTest.java
new file mode 100644
index 000000000000..cf7e94676819
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/ThinLensTest.java
@@ -0,0 +1,19 @@
+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class ThinLensTest {
+
+    @Test
+    void testConvexLensRealImage() {
+        double v = ThinLens.imageDistance(10, 20);
+        assertEquals(20, v, 1e-6);
+    }
+
+    @Test
+    void testMagnification() {
+        assertEquals(2.0, ThinLens.magnification(20, 10), 1e-6);
+    }
+}

From 2911a7b52c1032591d2aa23feef5669fa43c7961 Mon Sep 17 00:00:00 2001
From: Rajuri Likhitha <likhitha.rajuri.03@gmail.com>
Date: Thu, 18 Dec 2025 02:44:12 +0530
Subject: [PATCH 1137/1338] ExtendedEuclideanAlgorithm (#7172)

* commit1

* Fix clang-format spacing in array declarations
---
 .../maths/ExtendedEuclideanAlgorithm.java     | 48 +++++++++++++++++++
 .../maths/ExtendedEuclideanAlgorithmTest.java | 47 ++++++++++++++++++
 2 files changed, 95 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/ExtendedEuclideanAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/maths/ExtendedEuclideanAlgorithmTest.java

diff --git a/src/main/java/com/thealgorithms/maths/ExtendedEuclideanAlgorithm.java b/src/main/java/com/thealgorithms/maths/ExtendedEuclideanAlgorithm.java
new file mode 100644
index 000000000000..4934d4493bf2
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/ExtendedEuclideanAlgorithm.java
@@ -0,0 +1,48 @@
+package com.thealgorithms.maths;
+
+/**
+ * In mathematics, the extended Euclidean algorithm is an extension to the
+ * Euclidean algorithm, and computes, in addition to the greatest common divisor
+ * (gcd) of integers a and b, also the coefficients of Bézout's identity, which
+ * are integers x and y such that ax + by = gcd(a, b).
+ *
+ * <p>
+ * For more details, see
+ * https://en.wikipedia.org/wiki/Extended_Euclidean_algorithm
+ */
+public final class ExtendedEuclideanAlgorithm {
+
+    private ExtendedEuclideanAlgorithm() {
+    }
+
+    /**
+     * This method implements the extended Euclidean algorithm.
+     *
+     * @param a The first number.
+     * @param b The second number.
+     * @return An array of three integers:
+     *         <ul>
+     *         <li>Index 0: The greatest common divisor (gcd) of a and b.</li>
+     *         <li>Index 1: The value of x in the equation ax + by = gcd(a, b).</li>
+     *         <li>Index 2: The value of y in the equation ax + by = gcd(a, b).</li>
+     *         </ul>
+     */
+    public static long[] extendedGCD(long a, long b) {
+        if (b == 0) {
+            // Base case: gcd(a, 0) = a. The equation is a*1 + 0*0 = a.
+            return new long[] {a, 1, 0};
+        }
+
+        // Recursive call
+        long[] result = extendedGCD(b, a % b);
+        long gcd = result[0];
+        long x1 = result[1];
+        long y1 = result[2];
+
+        // Update coefficients using the results from the recursive call
+        long x = y1;
+        long y = x1 - a / b * y1;
+
+        return new long[] {gcd, x, y};
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/ExtendedEuclideanAlgorithmTest.java b/src/test/java/com/thealgorithms/maths/ExtendedEuclideanAlgorithmTest.java
new file mode 100644
index 000000000000..56c005fd51ae
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/ExtendedEuclideanAlgorithmTest.java
@@ -0,0 +1,47 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class ExtendedEuclideanAlgorithmTest {
+
+    /**
+     * Verifies that the returned values satisfy Bézout's identity: a*x + b*y =
+     * gcd(a, b)
+     */
+    private void verifyBezoutIdentity(long a, long b, long[] result) {
+        long gcd = result[0];
+        long x = result[1];
+        long y = result[2];
+        assertEquals(a * x + b * y, gcd, "Bézout's identity failed for gcd(" + a + ", " + b + ")");
+    }
+
+    @Test
+    public void testExtendedGCD() {
+        // Test case 1: General case gcd(30, 50) = 10
+        long[] result1 = ExtendedEuclideanAlgorithm.extendedGCD(30, 50);
+        assertEquals(10, result1[0], "Test Case 1 Failed: gcd(30, 50) should be 10");
+        verifyBezoutIdentity(30, 50, result1);
+
+        // Test case 2: Another general case gcd(240, 46) = 2
+        long[] result2 = ExtendedEuclideanAlgorithm.extendedGCD(240, 46);
+        assertEquals(2, result2[0], "Test Case 2 Failed: gcd(240, 46) should be 2");
+        verifyBezoutIdentity(240, 46, result2);
+
+        // Test case 3: Base case where b is 0, gcd(10, 0) = 10
+        long[] result3 = ExtendedEuclideanAlgorithm.extendedGCD(10, 0);
+        assertEquals(10, result3[0], "Test Case 3 Failed: gcd(10, 0) should be 10");
+        verifyBezoutIdentity(10, 0, result3);
+
+        // Test case 4: Numbers are co-prime gcd(17, 13) = 1
+        long[] result4 = ExtendedEuclideanAlgorithm.extendedGCD(17, 13);
+        assertEquals(1, result4[0], "Test Case 4 Failed: gcd(17, 13) should be 1");
+        verifyBezoutIdentity(17, 13, result4);
+
+        // Test case 5: One number is a multiple of the other gcd(100, 20) = 20
+        long[] result5 = ExtendedEuclideanAlgorithm.extendedGCD(100, 20);
+        assertEquals(20, result5[0], "Test Case 5 Failed: gcd(100, 20) should be 20");
+        verifyBezoutIdentity(100, 20, result5);
+    }
+}

From 7d51c7f32097b488bab330f858391387ce4ce72c Mon Sep 17 00:00:00 2001
From: Saniya Mane <185913688+Saniya2701@users.noreply.github.com>
Date: Thu, 18 Dec 2025 13:25:03 +0530
Subject: [PATCH 1138/1338] Add additional edge cases to GCD unit tests 
 (#7174)

* Add additional edge cases to GCD unit tests

* Rename GCD test methods and add descriptive names

* Fix formatting in GCD tests

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../java/com/thealgorithms/maths/GCDTest.java | 58 +++++++++++++------
 1 file changed, 39 insertions(+), 19 deletions(-)

diff --git a/src/test/java/com/thealgorithms/maths/GCDTest.java b/src/test/java/com/thealgorithms/maths/GCDTest.java
index bac3f8f7596c..6bc870e94df9 100644
--- a/src/test/java/com/thealgorithms/maths/GCDTest.java
+++ b/src/test/java/com/thealgorithms/maths/GCDTest.java
@@ -6,57 +6,77 @@
 public class GCDTest {
 
     @Test
-    void test1() {
+    void testNegativeAndZeroThrowsException() {
         Assertions.assertThrows(ArithmeticException.class, () -> GCD.gcd(-1, 0));
     }
 
     @Test
-    void test2() {
+    void testPositiveAndNegativeThrowsException() {
         Assertions.assertThrows(ArithmeticException.class, () -> GCD.gcd(10, -2));
     }
 
     @Test
-    void test3() {
+    void testBothNegativeThrowsException() {
         Assertions.assertThrows(ArithmeticException.class, () -> GCD.gcd(-5, -3));
     }
 
     @Test
-    void test4() {
-        Assertions.assertEquals(GCD.gcd(0, 2), 2);
+    void testZeroAndPositiveReturnsPositive() {
+        Assertions.assertEquals(2, GCD.gcd(0, 2));
     }
 
     @Test
-    void test5() {
-        Assertions.assertEquals(GCD.gcd(10, 0), 10);
+    void testPositiveAndZeroReturnsPositive() {
+        Assertions.assertEquals(10, GCD.gcd(10, 0));
     }
 
     @Test
-    void test6() {
-        Assertions.assertEquals(GCD.gcd(1, 0), 1);
+    void testOneAndZeroReturnsOne() {
+        Assertions.assertEquals(1, GCD.gcd(1, 0));
     }
 
     @Test
-    void test7() {
-        Assertions.assertEquals(GCD.gcd(9, 6), 3);
+    void testTwoPositiveNumbers() {
+        Assertions.assertEquals(3, GCD.gcd(9, 6));
     }
 
     @Test
-    void test8() {
-        Assertions.assertEquals(GCD.gcd(48, 18, 30, 12), 6);
+    void testMultipleArgumentsGcd() {
+        Assertions.assertEquals(6, GCD.gcd(48, 18, 30, 12));
     }
 
     @Test
-    void testArrayGcd1() {
-        Assertions.assertEquals(GCD.gcd(new int[] {9, 6}), 3);
+    void testArrayInputGcd() {
+        Assertions.assertEquals(3, GCD.gcd(new int[] {9, 6}));
     }
 
     @Test
-    void testArrayGcd2() {
-        Assertions.assertEquals(GCD.gcd(new int[] {2 * 3 * 5 * 7, 2 * 5 * 5 * 5, 2 * 5 * 11, 5 * 5 * 5 * 13}), 5);
+    void testArrayWithCommonFactor() {
+        Assertions.assertEquals(5, GCD.gcd(new int[] {2 * 3 * 5 * 7, 2 * 5 * 5 * 5, 2 * 5 * 11, 5 * 5 * 5 * 13}));
     }
 
     @Test
-    void testArrayGcdForEmptyInput() {
-        Assertions.assertEquals(GCD.gcd(new int[] {}), 0);
+    void testEmptyArrayReturnsZero() {
+        Assertions.assertEquals(0, GCD.gcd(new int[] {}));
+    }
+
+    @Test
+    void testSameNumbers() {
+        Assertions.assertEquals(7, GCD.gcd(7, 7));
+    }
+
+    @Test
+    void testPrimeNumbersHaveGcdOne() {
+        Assertions.assertEquals(1, GCD.gcd(13, 17));
+    }
+
+    @Test
+    void testSingleElementArrayReturnsElement() {
+        Assertions.assertEquals(42, GCD.gcd(new int[] {42}));
+    }
+
+    @Test
+    void testLargeNumbers() {
+        Assertions.assertEquals(12, GCD.gcd(123456, 789012));
     }
 }

From 48e02b3bacc80600297812733c3ed483d265531c Mon Sep 17 00:00:00 2001
From: Adityaraj Solanki <adityasohanslnk@gmail.com>
Date: Thu, 18 Dec 2025 21:39:55 +0530
Subject: [PATCH 1139/1338] Add input validation for negative values in
 FibonacciSeries (#7177)

---
 .../java/com/thealgorithms/recursion/FibonacciSeries.java   | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java b/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
index e5f474085367..9bc6da2f7443 100644
--- a/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
+++ b/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
@@ -12,10 +12,12 @@ private FibonacciSeries() {
         throw new UnsupportedOperationException("Utility class");
     }
     public static int fibonacci(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("n must be a non-negative integer");
+        }
         if (n <= 1) {
             return n;
-        } else {
-            return fibonacci(n - 1) + fibonacci(n - 2);
         }
+        return fibonacci(n - 1) + fibonacci(n - 2);
     }
 }

From bb334881e938c8728d0add1f08d6b9d9f4bd8970 Mon Sep 17 00:00:00 2001
From: Gopal Gupta <143406016+gopaljilab@users.noreply.github.com>
Date: Sat, 20 Dec 2025 19:12:34 +0530
Subject: [PATCH 1140/1338] Implement LengthOfLastWord algorithm and add JUnit
 tests (#7057)

* Implement LengthOfLastWord algorithm in strings package

* Add JUnit tests for LengthOfLastWord algorithm

* style: fix import order and spacing for clang-format
---
 .../strings/LengthOfLastWord.java             | 51 +++++++++++++++++++
 .../strings/LengthOfLastWordTest.java         | 18 +++++++
 2 files changed, 69 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/LengthOfLastWord.java
 create mode 100644 src/test/java/com/thealgorithms/strings/LengthOfLastWordTest.java

diff --git a/src/main/java/com/thealgorithms/strings/LengthOfLastWord.java b/src/main/java/com/thealgorithms/strings/LengthOfLastWord.java
new file mode 100644
index 000000000000..7eed59a5ef99
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/LengthOfLastWord.java
@@ -0,0 +1,51 @@
+package com.thealgorithms.strings;
+
+/**
+ * The {@code LengthOfLastWord} class provides a utility method to determine
+ * the length of the last word in a given string.
+ *
+ * <p>A "word" is defined as a maximal substring consisting of non-space
+ * characters only. Trailing spaces at the end of the string are ignored.
+ *
+ * <p><strong>Example:</strong>
+ * <pre>{@code
+ * LengthOfLastWord obj = new LengthOfLastWord();
+ * System.out.println(obj.lengthOfLastWord("Hello World"));  // Output: 5
+ * System.out.println(obj.lengthOfLastWord("  fly me   to   the moon  "));  // Output: 4
+ * System.out.println(obj.lengthOfLastWord("luffy is still joyboy"));  // Output: 6
+ * }</pre>
+ *
+ * <p>This implementation runs in O(n) time complexity, where n is the length
+ * of the input string, and uses O(1) additional space.
+ */
+public class LengthOfLastWord {
+
+    /**
+     * Returns the length of the last word in the specified string.
+     *
+     * <p>The method iterates from the end of the string, skipping trailing
+     * spaces first, and then counts the number of consecutive non-space characters
+     * characters until another space (or the beginning of the string) is reached.
+     *
+     * @param s the input string to analyze
+     * @return the length of the last word in {@code s}; returns 0 if there is no word
+     * @throws NullPointerException if {@code s} is {@code null}
+     */
+    public int lengthOfLastWord(String s) {
+        int sizeOfString = s.length() - 1;
+        int lastWordLength = 0;
+
+        // Skip trailing spaces from the end of the string
+        while (sizeOfString >= 0 && s.charAt(sizeOfString) == ' ') {
+            sizeOfString--;
+        }
+
+        // Count the characters of the last word
+        while (sizeOfString >= 0 && s.charAt(sizeOfString) != ' ') {
+            lastWordLength++;
+            sizeOfString--;
+        }
+
+        return lastWordLength;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/LengthOfLastWordTest.java b/src/test/java/com/thealgorithms/strings/LengthOfLastWordTest.java
new file mode 100644
index 000000000000..46a0a6eb0008
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/LengthOfLastWordTest.java
@@ -0,0 +1,18 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class LengthOfLastWordTest {
+    @Test
+    public void testLengthOfLastWord() {
+        assertEquals(5, new LengthOfLastWord().lengthOfLastWord("Hello World"));
+        assertEquals(4, new LengthOfLastWord().lengthOfLastWord("  fly me   to   the moon  "));
+        assertEquals(6, new LengthOfLastWord().lengthOfLastWord("luffy is still joyboy"));
+        assertEquals(5, new LengthOfLastWord().lengthOfLastWord("Hello"));
+        assertEquals(0, new LengthOfLastWord().lengthOfLastWord("     "));
+        assertEquals(0, new LengthOfLastWord().lengthOfLastWord(""));
+        assertEquals(3, new LengthOfLastWord().lengthOfLastWord("JUST LIE  "));
+    }
+}

From 1eb0d61730e033bbc37bab67f795f9fa3a8fc2b1 Mon Sep 17 00:00:00 2001
From: HxCodes <harshitsingh64053@gmail.com>
Date: Sun, 21 Dec 2025 21:03:25 +0530
Subject: [PATCH 1141/1338] Improve documentation and inline comments for
 QuickSort algorithm (#7182)

* Improve QuickSort documentation with detailed comments and explanations

* Format QuickSort documentation and fix JavaDoc layout
---
 .../com/thealgorithms/sorts/QuickSort.java    | 67 +++++++++++++------
 1 file changed, 45 insertions(+), 22 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/QuickSort.java b/src/main/java/com/thealgorithms/sorts/QuickSort.java
index a025e6909259..b0ca8b9f159d 100644
--- a/src/main/java/com/thealgorithms/sorts/QuickSort.java
+++ b/src/main/java/com/thealgorithms/sorts/QuickSort.java
@@ -1,24 +1,36 @@
 package com.thealgorithms.sorts;
 
 /**
- * @author Varun Upadhyay (https://github.com/varunu28)
- * @author Podshivalov Nikita (https://github.com/nikitap492)
+ * QuickSort is a divide-and-conquer sorting algorithm.
+ *
+ * <p>The algorithm selects a pivot element and partitions the array into two
+ * subarrays such that:
+ * <ul>
+ *   <li>Elements smaller than the pivot are placed on the left</li>
+ *   <li>Elements greater than the pivot are placed on the right</li>
+ * </ul>
+ *
+ * <p>The subarrays are then recursively sorted until the entire array is ordered.
+ *
+ * <p>This implementation uses randomization to reduce the probability of
+ * encountering worst-case performance on already sorted inputs.
+ *
+ * <p>Time Complexity:
+ * <ul>
+ *   <li>Best Case: O(n log n)</li>
+ *   <li>Average Case: O(n log n)</li>
+ *   <li>Worst Case: O(n^2)</li>
+ * </ul>
+ *
+ * <p>Space Complexity: O(log n) due to recursion stack (in-place sorting).
+ *
+ * @author Varun Upadhyay
+ * @author Podshivalov Nikita
  * @see SortAlgorithm
  */
+
 class QuickSort implements SortAlgorithm {
 
-    /**
-     * Generic Quick Sort algorithm.
-     *
-     * Time Complexity:
-     * - Best case: O(n log n) – pivot splits array roughly in half each time.
-     * - Average case: O(n log n)
-     * - Worst case: O(n^2) – occurs when pivot consistently produces unbalanced splits.
-     *
-     * Space Complexity: O(log n) – recursion stack, in-place sorting.
-     *
-     * @see SortAlgorithm
-     */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
         doSort(array, 0, array.length - 1);
@@ -28,27 +40,33 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
     /**
      * The sorting process
      *
-     * @param left The first index of an array
-     * @param right The last index of an array
      * @param array The array to be sorted
+     * @param left  The first index of an array
+     * @param right The last index of an array
      */
     private static <T extends Comparable<T>> void doSort(T[] array, final int left, final int right) {
+        // Continue sorting only if the subarray has more than one element
         if (left < right) {
+            // Randomly choose a pivot and partition the array
             final int pivot = randomPartition(array, left, right);
+            // Recursively sort elements before the pivot
             doSort(array, left, pivot - 1);
+            // Recursively sort elements after the pivot
             doSort(array, pivot, right);
         }
     }
 
     /**
-     * Randomize the array to avoid the basically ordered sequences
+     * Randomizes the array to avoid already ordered or nearly ordered sequences
      *
      * @param array The array to be sorted
-     * @param left The first index of an array
+     * @param left  The first index of an array
      * @param right The last index of an array
      * @return the partition index of the array
      */
     private static <T extends Comparable<T>> int randomPartition(T[] array, final int left, final int right) {
+        // Randomizing the pivot helps avoid worst-case performance
+        // for already sorted or nearly sorted arrays
         final int randomIndex = left + (int) (Math.random() * (right - left + 1));
         SortUtils.swap(array, randomIndex, right);
         return partition(array, left, right);
@@ -58,21 +76,26 @@ private static <T extends Comparable<T>> int randomPartition(T[] array, final in
      * This method finds the partition index for an array
      *
      * @param array The array to be sorted
-     * @param left The first index of an array
-     * @param right The last index of an array Finds the partition index of an
-     * array
+     * @param left  The first index of an array
+     * @param right The last index of an array
      */
     private static <T extends Comparable<T>> int partition(T[] array, int left, int right) {
         final int mid = (left + right) >>> 1;
+        // Choose the middle element as the pivot
         final T pivot = array[mid];
-
+        // Move the left and right pointers towards each other
         while (left <= right) {
+            // Move left pointer until an element >= pivot is found
             while (SortUtils.less(array[left], pivot)) {
                 ++left;
             }
+
+            // Move right pointer until an element <= pivot is found
             while (SortUtils.less(pivot, array[right])) {
                 --right;
             }
+
+            // Swap elements that are on the wrong side of the pivot
             if (left <= right) {
                 SortUtils.swap(array, left, right);
                 ++left;

From 2707da25e35f6973ceacdf4aa7dde9ecf7d4d34c Mon Sep 17 00:00:00 2001
From: NYAMATHABAD KOUSHIK SAI <120590127+koushik-sai@users.noreply.github.com>
Date: Tue, 23 Dec 2025 01:45:50 +0530
Subject: [PATCH 1142/1338] Add recursive factorial implementation with tests
 (#7178)

* Add recursive factorial implementation with tests

* [STYLE] Apply clang-format

* Move recursive factorial to recursion package and remove duplicate

* Move recursive factorial to recursion package and remove duplicate

* Apply clang-format to factorial recursion tests

* Apply clang-format to factorial recursion tests

---------

Co-authored-by: Koushik Sai <nyamathabadkoushik@gmail.com>
Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../thealgorithms/{maths => recursion}/FactorialRecursion.java  | 2 +-
 .../{maths => recursion}/FactorialRecursionTest.java            | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
 rename src/main/java/com/thealgorithms/{maths => recursion}/FactorialRecursion.java (92%)
 rename src/test/java/com/thealgorithms/{maths => recursion}/FactorialRecursionTest.java (96%)

diff --git a/src/main/java/com/thealgorithms/maths/FactorialRecursion.java b/src/main/java/com/thealgorithms/recursion/FactorialRecursion.java
similarity index 92%
rename from src/main/java/com/thealgorithms/maths/FactorialRecursion.java
rename to src/main/java/com/thealgorithms/recursion/FactorialRecursion.java
index d9bafd1e39e9..673f216bdc9a 100644
--- a/src/main/java/com/thealgorithms/maths/FactorialRecursion.java
+++ b/src/main/java/com/thealgorithms/recursion/FactorialRecursion.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.recursion;
 
 public final class FactorialRecursion {
     private FactorialRecursion() {
diff --git a/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java b/src/test/java/com/thealgorithms/recursion/FactorialRecursionTest.java
similarity index 96%
rename from src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java
rename to src/test/java/com/thealgorithms/recursion/FactorialRecursionTest.java
index db18b46356b4..198fcd558f63 100644
--- a/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java
+++ b/src/test/java/com/thealgorithms/recursion/FactorialRecursionTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.maths;
+package com.thealgorithms.recursion;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;

From 51335cc18adc988848bfec71fb291b39928e05dc Mon Sep 17 00:00:00 2001
From: NYAMATHABAD KOUSHIK SAI <120590127+koushik-sai@users.noreply.github.com>
Date: Sat, 27 Dec 2025 22:25:23 +0530
Subject: [PATCH 1143/1338] Add Immutable HashMap implementation (#7183)

* Add immutable HashMap implementation

* Add immutable HashMap implementation

* Applied clang-format

---------

Co-authored-by: Koushik Sai <nyamathabadkoushik@gmail.com>
---
 .../hashmap/hashing/ImmutableHashMap.java     | 115 ++++++++++++++++++
 .../hashmap/hashing/ImmutableHashMapTest.java |  55 +++++++++
 2 files changed, 170 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/hashmap/hashing/ImmutableHashMap.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/hashmap/hashing/ImmutableHashMapTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/ImmutableHashMap.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/ImmutableHashMap.java
new file mode 100644
index 000000000000..f6e09ec623b6
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/ImmutableHashMap.java
@@ -0,0 +1,115 @@
+package com.thealgorithms.datastructures.hashmap.hashing;
+
+/**
+ * Immutable HashMap implementation using separate chaining.
+ *
+ * <p>This HashMap does not allow modification of existing instances.
+ * Any update operation returns a new ImmutableHashMap.
+ *
+ * @param <K> key type
+ * @param <V> value type
+ */
+public final class ImmutableHashMap<K, V> {
+
+    private static final int DEFAULT_CAPACITY = 16;
+
+    private final Node<K, V>[] table;
+    private final int size;
+
+    /**
+     * Private constructor to enforce immutability.
+     */
+    private ImmutableHashMap(Node<K, V>[] table, int size) {
+        this.table = table;
+        this.size = size;
+    }
+
+    /**
+     * Creates an empty ImmutableHashMap.
+     *
+     * @param <K> key type
+     * @param <V> value type
+     * @return empty ImmutableHashMap
+     */
+    @SuppressWarnings({"unchecked", "rawtypes"})
+    public static <K, V> ImmutableHashMap<K, V> empty() {
+        Node<K, V>[] table = (Node<K, V>[]) new Node[DEFAULT_CAPACITY];
+        return new ImmutableHashMap<>(table, 0);
+    }
+
+    /**
+     * Returns a new ImmutableHashMap with the given key-value pair added.
+     *
+     * @param key key to add
+     * @param value value to associate
+     * @return new ImmutableHashMap instance
+     */
+    public ImmutableHashMap<K, V> put(K key, V value) {
+        Node<K, V>[] newTable = table.clone();
+        int index = hash(key);
+
+        newTable[index] = new Node<>(key, value, newTable[index]);
+        return new ImmutableHashMap<>(newTable, size + 1);
+    }
+
+    /**
+     * Retrieves the value associated with the given key.
+     *
+     * @param key key to search
+     * @return value if found, otherwise null
+     */
+    public V get(K key) {
+        int index = hash(key);
+        Node<K, V> current = table[index];
+
+        while (current != null) {
+            if ((key == null && current.key == null) || (key != null && key.equals(current.key))) {
+                return current.value;
+            }
+            current = current.next;
+        }
+        return null;
+    }
+
+    /**
+     * Checks whether the given key exists in the map.
+     *
+     * @param key key to check
+     * @return true if key exists, false otherwise
+     */
+    public boolean containsKey(K key) {
+        return get(key) != null;
+    }
+
+    /**
+     * Returns the number of key-value pairs.
+     *
+     * @return size of the map
+     */
+    public int size() {
+        return size;
+    }
+
+    /**
+     * Computes hash index for a given key.
+     */
+    private int hash(K key) {
+        return key == null ? 0 : (key.hashCode() & Integer.MAX_VALUE) % table.length;
+    }
+
+    /**
+     * Node class for separate chaining.
+     */
+    private static final class Node<K, V> {
+
+        private final K key;
+        private final V value;
+        private final Node<K, V> next;
+
+        private Node(K key, V value, Node<K, V> next) {
+            this.key = key;
+            this.value = value;
+            this.next = next;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/ImmutableHashMapTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/ImmutableHashMapTest.java
new file mode 100644
index 000000000000..3d3fe63d775a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/ImmutableHashMapTest.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.datastructures.hashmap.hashing;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class ImmutableHashMapTest {
+
+    @Test
+    void testEmptyMap() {
+        ImmutableHashMap<String, Integer> map = ImmutableHashMap.<String, Integer>empty();
+
+        assertEquals(0, map.size());
+        assertNull(map.get("A"));
+    }
+
+    @Test
+    void testPutDoesNotModifyOriginalMap() {
+        ImmutableHashMap<String, Integer> map1 = ImmutableHashMap.<String, Integer>empty();
+
+        ImmutableHashMap<String, Integer> map2 = map1.put("A", 1);
+
+        assertEquals(0, map1.size());
+        assertEquals(1, map2.size());
+        assertNull(map1.get("A"));
+        assertEquals(1, map2.get("A"));
+    }
+
+    @Test
+    void testMultiplePuts() {
+        ImmutableHashMap<String, Integer> map = ImmutableHashMap.<String, Integer>empty().put("A", 1).put("B", 2);
+
+        assertEquals(2, map.size());
+        assertEquals(1, map.get("A"));
+        assertEquals(2, map.get("B"));
+    }
+
+    @Test
+    void testContainsKey() {
+        ImmutableHashMap<String, Integer> map = ImmutableHashMap.<String, Integer>empty().put("X", 100);
+
+        assertTrue(map.containsKey("X"));
+        assertFalse(map.containsKey("Y"));
+    }
+
+    @Test
+    void testNullKey() {
+        ImmutableHashMap<String, Integer> map = ImmutableHashMap.<String, Integer>empty().put(null, 50);
+
+        assertEquals(50, map.get(null));
+    }
+}

From d382e656f20eaddc2d91c723519a2d8775e7dc57 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20S=C3=A1nchez=20N=C3=BA=C3=B1ez?=
 <dsannue@upv.edu.es>
Date: Sun, 28 Dec 2025 10:53:12 +0100
Subject: [PATCH 1144/1338] Adding method to check wether a matrix is
 stochastic (#7184)

* Add StochasticMatrix utility class

This class provides methods to check if a matrix is row-stochastic or column-stochastic, ensuring all elements are non-negative and the sums of rows or columns equal 1.

* Change package from maths to matrix

Updated package declaration for StochasticMatrix class.

* Change package declaration in StochasticMatrixTest

* Delete src/test/java/com/thealgorithms/StochasticMatrixTest.java

* Refactor matrix initialization for test cases

* Fix formatting of matrix initialization in tests

* Remove unnecessary newline in StochasticMatrix

* Add import statement for JUnit in StochasticMatrixTest

* Add additional assertions to StochasticMatrixTest

* Clean up import statements in StochasticMatrixTest

Removed unused import statements for cleaner code.

* Reorder import statements in StochasticMatrixTest

* Remove unused import assertThrows from StochasticMatrixTest

Removed unused import for assertThrows.
---
 .../matrix/StochasticMatrix.java              | 74 +++++++++++++++++++
 .../matrix/StochasticMatrixTest.java          | 28 +++++++
 2 files changed, 102 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/matrix/StochasticMatrix.java
 create mode 100644 src/test/java/com/thealgorithms/matrix/StochasticMatrixTest.java

diff --git a/src/main/java/com/thealgorithms/matrix/StochasticMatrix.java b/src/main/java/com/thealgorithms/matrix/StochasticMatrix.java
new file mode 100644
index 000000000000..8b071113f9cc
--- /dev/null
+++ b/src/main/java/com/thealgorithms/matrix/StochasticMatrix.java
@@ -0,0 +1,74 @@
+package com.thealgorithms.matrix;
+
+/**
+ * Utility class to check whether a matrix is stochastic.
+ * A matrix is stochastic if all its elements are non-negative
+ * and the sum of each row or column is equal to 1.
+ *Reference: https://en.wikipedia.org/wiki/Stochastic_matrix
+ */
+public final class StochasticMatrix {
+
+    private static final double TOLERANCE = 1e-9;
+
+    private StochasticMatrix() {
+        // Utility class
+    }
+    /**
+     * Checks if a matrix is row-stochastic.
+     *
+     * @param matrix the matrix to check
+     * @return true if the matrix is row-stochastic
+     * @throws IllegalArgumentException if matrix is null or empty
+     */
+    public static boolean isRowStochastic(double[][] matrix) {
+        validateMatrix(matrix);
+
+        for (double[] row : matrix) {
+            double sum = 0.0;
+            for (double value : row) {
+                if (value < 0) {
+                    return false;
+                }
+                sum += value;
+            }
+            if (Math.abs(sum - 1.0) > TOLERANCE) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Checks if a matrix is column-stochastic.
+     *
+     * @param matrix the matrix to check
+     * @return true if the matrix is column-stochastic
+     * @throws IllegalArgumentException if matrix is null or empty
+     */
+    public static boolean isColumnStochastic(double[][] matrix) {
+        validateMatrix(matrix);
+
+        int rows = matrix.length;
+        int cols = matrix[0].length;
+
+        for (int j = 0; j < cols; j++) {
+            double sum = 0.0;
+            for (int i = 0; i < rows; i++) {
+                if (matrix[i][j] < 0) {
+                    return false;
+                }
+                sum += matrix[i][j];
+            }
+            if (Math.abs(sum - 1.0) > TOLERANCE) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private static void validateMatrix(double[][] matrix) {
+        if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
+            throw new IllegalArgumentException("Matrix must not be null or empty");
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/matrix/StochasticMatrixTest.java b/src/test/java/com/thealgorithms/matrix/StochasticMatrixTest.java
new file mode 100644
index 000000000000..1bba918dadac
--- /dev/null
+++ b/src/test/java/com/thealgorithms/matrix/StochasticMatrixTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.matrix;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class StochasticMatrixTest {
+
+    @Test
+    void testRowStochasticMatrix() {
+        double[][] matrix = {{0.2, 0.5, 0.3}, {0.1, 0.6, 0.3}};
+        assertTrue(StochasticMatrix.isRowStochastic(matrix));
+        assertFalse(StochasticMatrix.isColumnStochastic(matrix));
+    }
+
+    @Test
+    void testColumnStochasticMatrix() {
+        double[][] matrix = {{0.4, 0.2}, {0.6, 0.8}};
+        assertTrue(StochasticMatrix.isColumnStochastic(matrix));
+    }
+
+    @Test
+    void testInvalidMatrix() {
+        double[][] matrix = {{0.5, -0.5}, {0.5, 1.5}};
+        assertFalse(StochasticMatrix.isRowStochastic(matrix));
+    }
+}

From 35556fe1f14d24f901d37bb7dcab6ad3faf75a91 Mon Sep 17 00:00:00 2001
From: Patil Arpita <arpitapatil.work@gmail.com>
Date: Mon, 29 Dec 2025 18:57:31 +0530
Subject: [PATCH 1145/1338] Added 0/1 Knapsack Algorithm using Dynamic
 Programming in Java (#6789)

* Added 0/1 Knapsack Algorithm using Dynamic Programming in Java

* Fix Checkstyle whitespace issues in Knapsack.java

* Formatted Knapsack.java to pass linter and added 0/1 Knapsack algorithm

* Formatted Knapsack.java to pass linter and added 0/1 Knapsack algorithm

* Formatted Knapsack.java to pass linter and added 0/1 Knapsack algorithm

* Formatted Knapsack.java to pass linter and added 0/1 Knapsack algorithm

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../dynamicprogramming/Knapsack.java          | 59 +++++++++++++------
 1 file changed, 41 insertions(+), 18 deletions(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java b/src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java
index 134561766830..0d4c8d501f9f 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Knapsack.java
@@ -3,53 +3,76 @@
 import java.util.Arrays;
 
 /**
- * A Dynamic Programming based solution for the 0-1 Knapsack problem.
- * This class provides a method, `knapSack`, that calculates the maximum value that can be
- * obtained from a given set of items with weights and values, while not exceeding a
- * given weight capacity.
+ * 0/1 Knapsack Problem - Dynamic Programming solution.
  *
- * @see <a href="https://en.wikipedia.org/?title=0-1_Knapsack_problem">0-1 Knapsack Problem </a>
+ * This algorithm solves the classic optimization problem where we have n items,
+ * each with a weight and a value. The goal is to maximize the total value
+ * without exceeding the knapsack's weight capacity.
+ *
+ * Time Complexity: O(n * W)
+ * Space Complexity: O(W)
+ *
+ * Example:
+ * values = {60, 100, 120}
+ * weights = {10, 20, 30}
+ * W = 50
+ * Output: 220
+ *
+ * @author Arpita
+ * @see <a href="https://en.wikipedia.org/wiki/Knapsack_problem">Knapsack Problem</a>
  */
 public final class Knapsack {
 
     private Knapsack() {
     }
 
+    /**
+     * Validates the input to ensure correct constraints.
+     */
     private static void throwIfInvalidInput(final int weightCapacity, final int[] weights, final int[] values) {
         if (weightCapacity < 0) {
             throw new IllegalArgumentException("Weight capacity should not be negative.");
         }
         if (weights == null || values == null || weights.length != values.length) {
-            throw new IllegalArgumentException("Input arrays must not be null and must have the same length.");
+            throw new IllegalArgumentException("Weights and values must be non-null and of the same length.");
         }
         if (Arrays.stream(weights).anyMatch(w -> w <= 0)) {
-            throw new IllegalArgumentException("Input array should not contain non-positive weight(s).");
+            throw new IllegalArgumentException("Weights must be positive.");
         }
     }
 
     /**
-     * Solves the 0-1 Knapsack problem using Dynamic Programming.
+     * Solves the 0/1 Knapsack problem using Dynamic Programming (bottom-up approach).
      *
      * @param weightCapacity The maximum weight capacity of the knapsack.
-     * @param weights        An array of item weights.
-     * @param values         An array of item values.
-     * @return The maximum value that can be obtained without exceeding the weight capacity.
-     * @throws IllegalArgumentException If the input arrays are null or have different lengths.
+     * @param weights        The array of item weights.
+     * @param values         The array of item values.
+     * @return The maximum total value achievable without exceeding capacity.
      */
-    public static int knapSack(final int weightCapacity, final int[] weights, final int[] values) throws IllegalArgumentException {
+    public static int knapSack(final int weightCapacity, final int[] weights, final int[] values) {
         throwIfInvalidInput(weightCapacity, weights, values);
 
-        // DP table to store the state of the maximum possible return for a given weight capacity.
         int[] dp = new int[weightCapacity + 1];
 
+        // Fill dp[] array iteratively
         for (int i = 0; i < values.length; i++) {
-            for (int w = weightCapacity; w > 0; w--) {
-                if (weights[i] <= w) {
-                    dp[w] = Math.max(dp[w], dp[w - weights[i]] + values[i]);
-                }
+            for (int w = weightCapacity; w >= weights[i]; w--) {
+                dp[w] = Math.max(dp[w], dp[w - weights[i]] + values[i]);
             }
         }
 
         return dp[weightCapacity];
     }
+
+    /*
+    // Example main method for local testing only.
+    public static void main(String[] args) {
+        int[] values = {60, 100, 120};
+        int[] weights = {10, 20, 30};
+        int weightCapacity = 50;
+
+        int maxValue = knapSack(weightCapacity, weights, values);
+        System.out.println("Maximum value = " + maxValue); // Output: 220
+    }
+    */
 }

From 6149ec7fed62c68d0ac6e0e91f9e9125d43bf385 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Date: Mon, 29 Dec 2025 16:06:23 +0100
Subject: [PATCH 1146/1338] Update DIRECTORY.md (#7093)

Co-authored-by: DenizAltunkapan <DenizAltunkapan@users.noreply.github.com>
---
 DIRECTORY.md | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6ea83fc6a60a..deaf59636fa4 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -80,6 +80,7 @@
           - 📄 [ECC](src/main/java/com/thealgorithms/ciphers/ECC.java)
           - 📄 [HillCipher](src/main/java/com/thealgorithms/ciphers/HillCipher.java)
           - 📄 [MonoAlphabetic](src/main/java/com/thealgorithms/ciphers/MonoAlphabetic.java)
+          - 📄 [OneTimePadCipher](src/main/java/com/thealgorithms/ciphers/OneTimePadCipher.java)
           - 📄 [PermutationCipher](src/main/java/com/thealgorithms/ciphers/PermutationCipher.java)
           - 📄 [PlayfairCipher](src/main/java/com/thealgorithms/ciphers/PlayfairCipher.java)
           - 📄 [Polybius](src/main/java/com/thealgorithms/ciphers/Polybius.java)
@@ -200,6 +201,7 @@
               - 📄 [GenericHashMapUsingArrayList](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayList.java)
               - 📄 [HashMap](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMap.java)
               - 📄 [HashMapCuckooHashing](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashing.java)
+              - 📄 [ImmutableHashMap](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/ImmutableHashMap.java)
               - 📄 [Intersection](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Intersection.java)
               - 📄 [LinearProbingHashMap](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMap.java)
               - 📄 [MainCuckooHashing](src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java)
@@ -266,8 +268,10 @@
             - 📄 [BSTRecursiveGeneric](src/main/java/com/thealgorithms/datastructures/trees/BSTRecursiveGeneric.java)
             - 📄 [BTree](src/main/java/com/thealgorithms/datastructures/trees/BTree.java)
             - 📄 [BinaryTree](src/main/java/com/thealgorithms/datastructures/trees/BinaryTree.java)
+            - 📄 [BinaryTreeToString](src/main/java/com/thealgorithms/datastructures/trees/BinaryTreeToString.java)
             - 📄 [BoundaryTraversal](src/main/java/com/thealgorithms/datastructures/trees/BoundaryTraversal.java)
             - 📄 [CeilInBinarySearchTree](src/main/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTree.java)
+            - 📄 [CentroidDecomposition](src/main/java/com/thealgorithms/datastructures/trees/CentroidDecomposition.java)
             - 📄 [CheckBinaryTreeIsValidBST](src/main/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBST.java)
             - 📄 [CheckIfBinaryTreeBalanced](src/main/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalanced.java)
             - 📄 [CheckTreeIsSymmetric](src/main/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetric.java)
@@ -287,6 +291,7 @@
             - 📄 [SameTreesCheck](src/main/java/com/thealgorithms/datastructures/trees/SameTreesCheck.java)
             - 📄 [SegmentTree](src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java)
             - 📄 [SplayTree](src/main/java/com/thealgorithms/datastructures/trees/SplayTree.java)
+            - 📄 [ThreadedBinaryTree](src/main/java/com/thealgorithms/datastructures/trees/ThreadedBinaryTree.java)
             - 📄 [Treap](src/main/java/com/thealgorithms/datastructures/trees/Treap.java)
             - 📄 [TreeRandomNode](src/main/java/com/thealgorithms/datastructures/trees/TreeRandomNode.java)
             - 📄 [Trie](src/main/java/com/thealgorithms/datastructures/trees/Trie.java)
@@ -426,6 +431,7 @@
           - 📄 [AbsoluteMax](src/main/java/com/thealgorithms/maths/AbsoluteMax.java)
           - 📄 [AbsoluteMin](src/main/java/com/thealgorithms/maths/AbsoluteMin.java)
           - 📄 [AbsoluteValue](src/main/java/com/thealgorithms/maths/AbsoluteValue.java)
+          - 📄 [AbundantNumber](src/main/java/com/thealgorithms/maths/AbundantNumber.java)
           - 📄 [AliquotSum](src/main/java/com/thealgorithms/maths/AliquotSum.java)
           - 📄 [AmicableNumber](src/main/java/com/thealgorithms/maths/AmicableNumber.java)
           - 📄 [Area](src/main/java/com/thealgorithms/maths/Area.java)
@@ -452,10 +458,11 @@
           - 📄 [EulerMethod](src/main/java/com/thealgorithms/maths/EulerMethod.java)
           - 📄 [EulerPseudoprime](src/main/java/com/thealgorithms/maths/EulerPseudoprime.java)
           - 📄 [EulersFunction](src/main/java/com/thealgorithms/maths/EulersFunction.java)
+          - 📄 [EvilNumber](src/main/java/com/thealgorithms/maths/EvilNumber.java)
+          - 📄 [ExtendedEuclideanAlgorithm](src/main/java/com/thealgorithms/maths/ExtendedEuclideanAlgorithm.java)
           - 📄 [FFT](src/main/java/com/thealgorithms/maths/FFT.java)
           - 📄 [FFTBluestein](src/main/java/com/thealgorithms/maths/FFTBluestein.java)
           - 📄 [Factorial](src/main/java/com/thealgorithms/maths/Factorial.java)
-          - 📄 [FactorialRecursion](src/main/java/com/thealgorithms/maths/FactorialRecursion.java)
           - 📄 [FastExponentiation](src/main/java/com/thealgorithms/maths/FastExponentiation.java)
           - 📄 [FastInverseSqrt](src/main/java/com/thealgorithms/maths/FastInverseSqrt.java)
           - 📄 [FibonacciJavaStreams](src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java)
@@ -489,6 +496,7 @@
           - 📄 [LinearDiophantineEquationsSolver](src/main/java/com/thealgorithms/maths/LinearDiophantineEquationsSolver.java)
           - 📄 [LongDivision](src/main/java/com/thealgorithms/maths/LongDivision.java)
           - 📄 [LucasSeries](src/main/java/com/thealgorithms/maths/LucasSeries.java)
+          - 📄 [LuckyNumber](src/main/java/com/thealgorithms/maths/LuckyNumber.java)
           - 📄 [MagicSquare](src/main/java/com/thealgorithms/maths/MagicSquare.java)
           - 📄 [MathBuilder](src/main/java/com/thealgorithms/maths/MathBuilder.java)
           - 📄 [MaxValue](src/main/java/com/thealgorithms/maths/MaxValue.java)
@@ -561,6 +569,7 @@
           - 📄 [PrintAMatrixInSpiralOrder](src/main/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrder.java)
           - 📄 [RotateMatrixBy90Degrees](src/main/java/com/thealgorithms/matrix/RotateMatrixBy90Degrees.java)
           - 📄 [SolveSystem](src/main/java/com/thealgorithms/matrix/SolveSystem.java)
+          - 📄 [StochasticMatrix](src/main/java/com/thealgorithms/matrix/StochasticMatrix.java)
           - 📁 **matrixexponentiation**
             - 📄 [Fibonacci](src/main/java/com/thealgorithms/matrix/matrixexponentiation/Fibonacci.java)
           - 📁 **utils**
@@ -628,6 +637,8 @@
           - 📄 [Kinematics](src/main/java/com/thealgorithms/physics/Kinematics.java)
           - 📄 [ProjectileMotion](src/main/java/com/thealgorithms/physics/ProjectileMotion.java)
           - 📄 [SimplePendulumRK4](src/main/java/com/thealgorithms/physics/SimplePendulumRK4.java)
+          - 📄 [SnellLaw](src/main/java/com/thealgorithms/physics/SnellLaw.java)
+          - 📄 [ThinLens](src/main/java/com/thealgorithms/physics/ThinLens.java)
         - 📁 **puzzlesandgames**
           - 📄 [TowerOfHanoi](src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java)
           - 📄 [WordBoggle](src/main/java/com/thealgorithms/puzzlesandgames/WordBoggle.java)
@@ -640,6 +651,7 @@
           - 📄 [ReservoirSampling](src/main/java/com/thealgorithms/randomized/ReservoirSampling.java)
         - 📁 **recursion**
           - 📄 [DiceThrower](src/main/java/com/thealgorithms/recursion/DiceThrower.java)
+          - 📄 [FactorialRecursion](src/main/java/com/thealgorithms/recursion/FactorialRecursion.java)
           - 📄 [FibonacciSeries](src/main/java/com/thealgorithms/recursion/FibonacciSeries.java)
           - 📄 [GenerateSubsets](src/main/java/com/thealgorithms/recursion/GenerateSubsets.java)
           - 📄 [SylvesterSequence](src/main/java/com/thealgorithms/recursion/SylvesterSequence.java)
@@ -786,6 +798,7 @@
           - 📄 [StackPostfixNotation](src/main/java/com/thealgorithms/stacks/StackPostfixNotation.java)
           - 📄 [StackUsingTwoQueues](src/main/java/com/thealgorithms/stacks/StackUsingTwoQueues.java)
           - 📄 [TrappingRainwater](src/main/java/com/thealgorithms/stacks/TrappingRainwater.java)
+          - 📄 [ValidParentheses](src/main/java/com/thealgorithms/stacks/ValidParentheses.java)
         - 📁 **strings**
           - 📄 [AhoCorasick](src/main/java/com/thealgorithms/strings/AhoCorasick.java)
           - 📄 [Alphabetical](src/main/java/com/thealgorithms/strings/Alphabetical.java)
@@ -800,6 +813,7 @@
           - 📄 [Isogram](src/main/java/com/thealgorithms/strings/Isogram.java)
           - 📄 [Isomorphic](src/main/java/com/thealgorithms/strings/Isomorphic.java)
           - 📄 [KMP](src/main/java/com/thealgorithms/strings/KMP.java)
+          - 📄 [LengthOfLastWord](src/main/java/com/thealgorithms/strings/LengthOfLastWord.java)
           - 📄 [LetterCombinationsOfPhoneNumber](src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java)
           - 📄 [LongestCommonPrefix](src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java)
           - 📄 [LongestNonRepetitiveSubstring](src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java)
@@ -904,6 +918,7 @@
           - 📄 [ECCTest](src/test/java/com/thealgorithms/ciphers/ECCTest.java)
           - 📄 [HillCipherTest](src/test/java/com/thealgorithms/ciphers/HillCipherTest.java)
           - 📄 [MonoAlphabeticTest](src/test/java/com/thealgorithms/ciphers/MonoAlphabeticTest.java)
+          - 📄 [OneTimePadCipherTest](src/test/java/com/thealgorithms/ciphers/OneTimePadCipherTest.java)
           - 📄 [PermutationCipherTest](src/test/java/com/thealgorithms/ciphers/PermutationCipherTest.java)
           - 📄 [PlayfairTest](src/test/java/com/thealgorithms/ciphers/PlayfairTest.java)
           - 📄 [PolybiusTest](src/test/java/com/thealgorithms/ciphers/PolybiusTest.java)
@@ -987,8 +1002,10 @@
             - 📄 [DynamicArrayTest](src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java)
           - 📁 **graphs**
             - 📄 [AStarTest](src/test/java/com/thealgorithms/datastructures/graphs/AStarTest.java)
+            - 📄 [BellmanFordTest](src/test/java/com/thealgorithms/datastructures/graphs/BellmanFordTest.java)
             - 📄 [BipartiteGraphDFSTest](src/test/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFSTest.java)
             - 📄 [BoruvkaAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/BoruvkaAlgorithmTest.java)
+            - 📄 [ConnectedComponentTest](src/test/java/com/thealgorithms/datastructures/graphs/ConnectedComponentTest.java)
             - 📄 [DialsAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/DialsAlgorithmTest.java)
             - 📄 [DijkstraAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithmTest.java)
             - 📄 [DijkstraOptimizedAlgorithmTest](src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java)
@@ -1011,6 +1028,7 @@
               - 📄 [GenericHashMapUsingArrayTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java)
               - 📄 [HashMapCuckooHashingTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapCuckooHashingTest.java)
               - 📄 [HashMapTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/HashMapTest.java)
+              - 📄 [ImmutableHashMapTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/ImmutableHashMapTest.java)
               - 📄 [IntersectionTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/IntersectionTest.java)
               - 📄 [LinearProbingHashMapTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/LinearProbingHashMapTest.java)
               - 📄 [MajorityElementTest](src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MajorityElementTest.java)
@@ -1069,8 +1087,10 @@
             - 📄 [BSTRecursiveTest](src/test/java/com/thealgorithms/datastructures/trees/BSTRecursiveTest.java)
             - 📄 [BTreeTest](src/test/java/com/thealgorithms/datastructures/trees/BTreeTest.java)
             - 📄 [BinaryTreeTest](src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java)
+            - 📄 [BinaryTreeToStringTest](src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeToStringTest.java)
             - 📄 [BoundaryTraversalTest](src/test/java/com/thealgorithms/datastructures/trees/BoundaryTraversalTest.java)
             - 📄 [CeilInBinarySearchTreeTest](src/test/java/com/thealgorithms/datastructures/trees/CeilInBinarySearchTreeTest.java)
+            - 📄 [CentroidDecompositionTest](src/test/java/com/thealgorithms/datastructures/trees/CentroidDecompositionTest.java)
             - 📄 [CheckBinaryTreeIsValidBSTTest](src/test/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBSTTest.java)
             - 📄 [CheckIfBinaryTreeBalancedTest](src/test/java/com/thealgorithms/datastructures/trees/CheckIfBinaryTreeBalancedTest.java)
             - 📄 [CheckTreeIsSymmetricTest](src/test/java/com/thealgorithms/datastructures/trees/CheckTreeIsSymmetricTest.java)
@@ -1084,6 +1104,7 @@
             - 📄 [QuadTreeTest](src/test/java/com/thealgorithms/datastructures/trees/QuadTreeTest.java)
             - 📄 [SameTreesCheckTest](src/test/java/com/thealgorithms/datastructures/trees/SameTreesCheckTest.java)
             - 📄 [SplayTreeTest](src/test/java/com/thealgorithms/datastructures/trees/SplayTreeTest.java)
+            - 📄 [ThreadedBinaryTreeTest](src/test/java/com/thealgorithms/datastructures/trees/ThreadedBinaryTreeTest.java)
             - 📄 [TreapTest](src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java)
             - 📄 [TreeTestUtils](src/test/java/com/thealgorithms/datastructures/trees/TreeTestUtils.java)
             - 📄 [TrieTest](src/test/java/com/thealgorithms/datastructures/trees/TrieTest.java)
@@ -1171,6 +1192,7 @@
           - 📄 [DinicTest](src/test/java/com/thealgorithms/graph/DinicTest.java)
           - 📄 [EdmondsKarpTest](src/test/java/com/thealgorithms/graph/EdmondsKarpTest.java)
           - 📄 [EdmondsTest](src/test/java/com/thealgorithms/graph/EdmondsTest.java)
+          - 📄 [GomoryHuTreeTest](src/test/java/com/thealgorithms/graph/GomoryHuTreeTest.java)
           - 📄 [HierholzerAlgorithmTest](src/test/java/com/thealgorithms/graph/HierholzerAlgorithmTest.java)
           - 📄 [HierholzerEulerianPathTest](src/test/java/com/thealgorithms/graph/HierholzerEulerianPathTest.java)
           - 📄 [HopcroftKarpTest](src/test/java/com/thealgorithms/graph/HopcroftKarpTest.java)
@@ -1208,6 +1230,7 @@
           - 📄 [AbsoluteMaxTest](src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java)
           - 📄 [AbsoluteMinTest](src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java)
           - 📄 [AbsoluteValueTest](src/test/java/com/thealgorithms/maths/AbsoluteValueTest.java)
+          - 📄 [AbundantNumberTest](src/test/java/com/thealgorithms/maths/AbundantNumberTest.java)
           - 📄 [AliquotSumTest](src/test/java/com/thealgorithms/maths/AliquotSumTest.java)
           - 📄 [AmicableNumberTest](src/test/java/com/thealgorithms/maths/AmicableNumberTest.java)
           - 📄 [AreaTest](src/test/java/com/thealgorithms/maths/AreaTest.java)
@@ -1233,8 +1256,9 @@
           - 📄 [EulerMethodTest](src/test/java/com/thealgorithms/maths/EulerMethodTest.java)
           - 📄 [EulerPseudoprimeTest](src/test/java/com/thealgorithms/maths/EulerPseudoprimeTest.java)
           - 📄 [EulersFunctionTest](src/test/java/com/thealgorithms/maths/EulersFunctionTest.java)
+          - 📄 [EvilNumberTest](src/test/java/com/thealgorithms/maths/EvilNumberTest.java)
+          - 📄 [ExtendedEuclideanAlgorithmTest](src/test/java/com/thealgorithms/maths/ExtendedEuclideanAlgorithmTest.java)
           - 📄 [FFTTest](src/test/java/com/thealgorithms/maths/FFTTest.java)
-          - 📄 [FactorialRecursionTest](src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java)
           - 📄 [FactorialTest](src/test/java/com/thealgorithms/maths/FactorialTest.java)
           - 📄 [FastExponentiationTest](src/test/java/com/thealgorithms/maths/FastExponentiationTest.java)
           - 📄 [FastInverseSqrtTests](src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java)
@@ -1269,6 +1293,7 @@
           - 📄 [LinearDiophantineEquationsSolverTest](src/test/java/com/thealgorithms/maths/LinearDiophantineEquationsSolverTest.java)
           - 📄 [LongDivisionTest](src/test/java/com/thealgorithms/maths/LongDivisionTest.java)
           - 📄 [LucasSeriesTest](src/test/java/com/thealgorithms/maths/LucasSeriesTest.java)
+          - 📄 [LuckyNumberTest](src/test/java/com/thealgorithms/maths/LuckyNumberTest.java)
           - 📄 [MathBuilderTest](src/test/java/com/thealgorithms/maths/MathBuilderTest.java)
           - 📄 [MaxValueTest](src/test/java/com/thealgorithms/maths/MaxValueTest.java)
           - 📄 [MeansTest](src/test/java/com/thealgorithms/maths/MeansTest.java)
@@ -1336,6 +1361,7 @@
           - 📄 [MirrorOfMatrixTest](src/test/java/com/thealgorithms/matrix/MirrorOfMatrixTest.java)
           - 📄 [PrintAMatrixInSpiralOrderTest](src/test/java/com/thealgorithms/matrix/PrintAMatrixInSpiralOrderTest.java)
           - 📄 [SolveSystemTest](src/test/java/com/thealgorithms/matrix/SolveSystemTest.java)
+          - 📄 [StochasticMatrixTest](src/test/java/com/thealgorithms/matrix/StochasticMatrixTest.java)
         - 📁 **misc**
           - 📄 [ColorContrastRatioTest](src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java)
           - 📄 [MapReduceTest](src/test/java/com/thealgorithms/misc/MapReduceTest.java)
@@ -1389,6 +1415,8 @@
           - 📄 [KinematicsTest](src/test/java/com/thealgorithms/physics/KinematicsTest.java)
           - 📄 [ProjectileMotionTest](src/test/java/com/thealgorithms/physics/ProjectileMotionTest.java)
           - 📄 [SimplePendulumRK4Test](src/test/java/com/thealgorithms/physics/SimplePendulumRK4Test.java)
+          - 📄 [SnellLawTest](src/test/java/com/thealgorithms/physics/SnellLawTest.java)
+          - 📄 [ThinLensTest](src/test/java/com/thealgorithms/physics/ThinLensTest.java)
         - 📁 **puzzlesandgames**
           - 📄 [TowerOfHanoiTest](src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java)
           - 📄 [WordBoggleTest](src/test/java/com/thealgorithms/puzzlesandgames/WordBoggleTest.java)
@@ -1401,6 +1429,7 @@
           - 📄 [ReservoirSamplingTest](src/test/java/com/thealgorithms/randomized/ReservoirSamplingTest.java)
         - 📁 **recursion**
           - 📄 [DiceThrowerTest](src/test/java/com/thealgorithms/recursion/DiceThrowerTest.java)
+          - 📄 [FactorialRecursionTest](src/test/java/com/thealgorithms/recursion/FactorialRecursionTest.java)
           - 📄 [FibonacciSeriesTest](src/test/java/com/thealgorithms/recursion/FibonacciSeriesTest.java)
           - 📄 [GenerateSubsetsTest](src/test/java/com/thealgorithms/recursion/GenerateSubsetsTest.java)
           - 📄 [SylvesterSequenceTest](src/test/java/com/thealgorithms/recursion/SylvesterSequenceTest.java)
@@ -1546,6 +1575,7 @@
           - 📄 [StackPostfixNotationTest](src/test/java/com/thealgorithms/stacks/StackPostfixNotationTest.java)
           - 📄 [StackUsingTwoQueuesTest](src/test/java/com/thealgorithms/stacks/StackUsingTwoQueuesTest.java)
           - 📄 [TrappingRainwaterTest](src/test/java/com/thealgorithms/stacks/TrappingRainwaterTest.java)
+          - 📄 [ValidParenthesesTest](src/test/java/com/thealgorithms/stacks/ValidParenthesesTest.java)
         - 📁 **strings**
           - 📄 [AhoCorasickTest](src/test/java/com/thealgorithms/strings/AhoCorasickTest.java)
           - 📄 [AlphabeticalTest](src/test/java/com/thealgorithms/strings/AlphabeticalTest.java)
@@ -1559,6 +1589,7 @@
           - 📄 [HorspoolSearchTest](src/test/java/com/thealgorithms/strings/HorspoolSearchTest.java)
           - 📄 [IsogramTest](src/test/java/com/thealgorithms/strings/IsogramTest.java)
           - 📄 [IsomorphicTest](src/test/java/com/thealgorithms/strings/IsomorphicTest.java)
+          - 📄 [LengthOfLastWordTest](src/test/java/com/thealgorithms/strings/LengthOfLastWordTest.java)
           - 📄 [LetterCombinationsOfPhoneNumberTest](src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java)
           - 📄 [LongestCommonPrefixTest](src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java)
           - 📄 [LongestNonRepetitiveSubstringTest](src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java)

From 0eda2a1db81424206effd7159af191870ab3a842 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Date: Mon, 29 Dec 2025 21:55:23 +0100
Subject: [PATCH 1147/1338] Add test requirement to pull request template
 (#7185)

* Add checklist item for test class inclusion

* Update pull request template for algorithm tests
---
 .github/pull_request_template.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index d9cc4c3c35c5..30b46bbf45b5 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -13,4 +13,5 @@ In order to reduce the number of notifications sent to the maintainers, please:
 - [ ] All filenames are in PascalCase.
 - [ ] All functions and variable names follow Java naming conventions.
 - [ ] All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
-- [ ] All new code is formatted with `clang-format -i --style=file path/to/your/file.java`
\ No newline at end of file
+- [ ] All new algorithms include a corresponding test class that validates their functionality.
+- [ ] All new code is formatted with `clang-format -i --style=file path/to/your/file.java`

From e945f1622490ff3b32e59d31780df27d0dc2ede4 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 1 Jan 2026 18:23:45 +0100
Subject: [PATCH 1148/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 12.3.0 to 12.3.1 (#7188)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 12.3.0 to 12.3.1.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-12.3.0...checkstyle-12.3.1)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 12.3.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index d60f8b9668e6..59a497427c0d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>12.3.0</version>
+                    <version>12.3.1</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 24389c06a29c3472eb1e64c211a585eb5f9a0ff4 Mon Sep 17 00:00:00 2001
From: Giridharan S <168095425+S-GIRI@users.noreply.github.com>
Date: Mon, 5 Jan 2026 21:40:24 +0530
Subject: [PATCH 1149/1338] Add detailed JavaDoc for AllPathsFromSourceToTarget
 algorithm (#7192)

Add detailed JavaDoc for AllPathsFromSourceToTarget
---
 .../AllPathsFromSourceToTarget.java           | 31 +++++++++++++++++--
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java b/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
index c35a36d97a57..269880b8ddae 100644
--- a/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
+++ b/src/main/java/com/thealgorithms/backtracking/AllPathsFromSourceToTarget.java
@@ -4,11 +4,36 @@
 import java.util.List;
 
 /**
- * Program description - To find all possible paths from source to destination
- * <a href="https://en.wikipedia.org/wiki/Shortest_path_problem">Wikipedia</a>
+ * Finds all possible simple paths from a given source vertex to a destination vertex
+ * in a directed graph using backtracking.
  *
- * @author <a href="https://github.com/siddhant2002">Siddhant Swarup Mallick</a>
+ * <p>This algorithm performs a Depth First Search (DFS) traversal while keeping track
+ * of visited vertices to avoid cycles. Whenever the destination vertex is reached,
+ * the current path is stored as one valid path.</p>
+ *
+ * <p><b>Key Characteristics:</b></p>
+ * <ul>
+ *   <li>Works on directed graphs</li>
+ *   <li>Does not allow revisiting vertices in the same path</li>
+ *   <li>Stores all possible paths from source to destination</li>
+ * </ul>
+ *
+ * <p><b>Time Complexity:</b></p>
+ * <ul>
+ *   <li>Worst Case: O(V!) — when the graph is fully connected</li>
+ * </ul>
+ *
+ * <p><b>Space Complexity:</b></p>
+ * <ul>
+ *   <li>O(V) for recursion stack and visited array</li>
+ *   <li>Additional space for storing all valid paths</li>
+ * </ul>
+ *
+ * <p>This implementation is intended for educational purposes.</p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Depth-first_search">Depth First Search</a>
  */
+
 @SuppressWarnings({"rawtypes", "unchecked"})
 public class AllPathsFromSourceToTarget {
 

From c06c0f03e3f8aa1390b866a1c9483e34c13fbda3 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 5 Jan 2026 22:50:29 +0100
Subject: [PATCH 1150/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 12.3.1 to 13.0.0 (#7193)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 12.3.1 to 13.0.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-12.3.1...checkstyle-13.0.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 59a497427c0d..73869d6dd942 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>12.3.1</version>
+                    <version>13.0.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 404e1404aa6f97c711bf9beb3d54c78097b28357 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 6 Jan 2026 22:38:42 +0100
Subject: [PATCH 1151/1338] chore(deps): bump org.junit:junit-bom from 6.0.1 to
 6.0.2 (#7194)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 6.0.1 to 6.0.2.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r6.0.1...r6.0.2)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 6.0.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 73869d6dd942..d3db730327d3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>6.0.1</version>
+                <version>6.0.2</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 938d06abb5f6a15ffadd260e1810f1a502679561 Mon Sep 17 00:00:00 2001
From: Rajesh Reddy <itsmerajeshreddy01@gmail.com>
Date: Wed, 7 Jan 2026 17:19:51 +0530
Subject: [PATCH 1152/1338] docs: clarify hash map vs HashMap terminology
 (#7195)

---
 .../java/com/thealgorithms/datastructures/hashmap/Readme.md     | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/Readme.md b/src/main/java/com/thealgorithms/datastructures/hashmap/Readme.md
index 252b06ea59b0..4400a97d8128 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/Readme.md
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/Readme.md
@@ -2,6 +2,8 @@
 
 A hash map organizes data so you can quickly look up values for a given key.
 
+> Note: The term “hash map” refers to the data structure concept, while `HashMap` refers specifically to Java’s implementation.
+
 ## Strengths:
 - **Fast lookups**: Lookups take O(1) time on average.
 - **Flexible keys**: Most data types can be used for keys, as long as they're hashable.

From ca4bebcbd55edd9dd39e4115cf9c0d962f8c4944 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 8 Jan 2026 09:56:14 +0100
Subject: [PATCH 1153/1338] chore(deps): bump peter-evans/create-pull-request
 from 7 to 8 in /.github/workflows (#7199)

chore(deps): bump peter-evans/create-pull-request in /.github/workflows

Bumps [peter-evans/create-pull-request](https://github.com/peter-evans/create-pull-request) from 7 to 8.
- [Release notes](https://github.com/peter-evans/create-pull-request/releases)
- [Commits](https://github.com/peter-evans/create-pull-request/compare/v7...v8)

---
updated-dependencies:
- dependency-name: peter-evans/create-pull-request
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/update-directorymd.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index 101d82427e38..aa553b46a23b 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -1,4 +1,4 @@
-name: Generate Directory Markdown
+name: Generate Directory Markdown
 
 on:
   push:
@@ -33,7 +33,7 @@ jobs:
           git diff --cached --quiet || git commit -m "Update DIRECTORY.md"
       
       - name: Create Pull Request
-        uses: peter-evans/create-pull-request@v7
+        uses: peter-evans/create-pull-request@v8
         with:
           token: ${{ secrets.REPO_SCOPED_TOKEN }}
           branch: update-directory

From fe6066b332d6e77f5f36292e9958dad367e0b731 Mon Sep 17 00:00:00 2001
From: Ahmed Allam <60698204+GziXnine@users.noreply.github.com>
Date: Fri, 9 Jan 2026 13:36:46 +0200
Subject: [PATCH 1154/1338] =?UTF-8?q?Add=20SmoothSort=20(Dijkstra=E2=80=99?=
 =?UTF-8?q?s=20adaptive=20in-place=20heapsort=20variant)=20(#7200)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* feat: implement Smooth Sort algorithm with detailed JavaDoc and test class

* style: format LEONARDO array for improved readability with clang-format

---------

Co-authored-by: Ahmed Allam <60698204+AllamF5J@users.noreply.github.com>
---
 .../com/thealgorithms/sorts/SmoothSort.java   | 168 ++++++++++++++++++
 .../thealgorithms/sorts/SmoothSortTest.java   |   8 +
 2 files changed, 176 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/SmoothSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/SmoothSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/SmoothSort.java b/src/main/java/com/thealgorithms/sorts/SmoothSort.java
new file mode 100644
index 000000000000..c45d6f1f02b2
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/SmoothSort.java
@@ -0,0 +1,168 @@
+package com.thealgorithms.sorts;
+
+/**
+ * Smooth Sort is an in-place, comparison-based sorting algorithm proposed by Edsger W. Dijkstra (1981).
+ *
+ * <p>It can be viewed as a variant of heapsort that maintains a forest of heap-ordered Leonardo trees
+ * (trees whose sizes are Leonardo numbers). The algorithm is adaptive: when the input is already
+ * sorted or nearly sorted, the heap invariants are often satisfied and the expensive rebalancing
+ * operations do little work, yielding near-linear behavior.
+ *
+ * <p>Time Complexity:
+ * <ul>
+ *   <li>Best case: O(n) for already sorted input</li>
+ *   <li>Average case: O(n log n)</li>
+ *   <li>Worst case: O(n log n)</li>
+ * </ul>
+ *
+ * <p>Space Complexity: O(1) auxiliary space (in-place).
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Smoothsort">Smoothsort</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Leonardo_number">Leonardo numbers</a>
+ * @see SortAlgorithm
+ */
+public class SmoothSort implements SortAlgorithm {
+
+    /**
+     * Leonardo numbers (L(0) = L(1) = 1, L(k+2) = L(k+1) + L(k) + 1) up to the largest value that
+     * fits into a signed 32-bit integer.
+     */
+    private static final int[] LEONARDO = {1, 1, 3, 5, 9, 15, 25, 41, 67, 109, 177, 287, 465, 753, 1219, 1973, 3193, 5167, 8361, 13529, 21891, 35421, 57313, 92735, 150049, 242785, 392835, 635621, 1028457, 1664079, 2692537, 4356617, 7049155, 11405773, 18454929, 29860703, 48315633, 78176337,
+        126491971, 204668309, 331160281, 535828591, 866988873, 1402817465};
+
+    /**
+     * Sorts the given array in ascending order using Smooth Sort.
+     *
+     * @param array the array to sort
+     * @param <T>   the element type
+     * @return the sorted array
+     */
+    @Override
+    public <T extends Comparable<T>> T[] sort(final T[] array) {
+        if (array.length < 2) {
+            return array;
+        }
+
+        final int last = array.length - 1;
+
+        // The forest shape is encoded as (p, pshift): p is a bit-vector of present tree orders,
+        // shifted right by pshift. pshift is the order of the rightmost (current) Leonardo tree.
+        long p = 1L;
+        int pshift = 1;
+
+        int head = 0;
+        while (head < last) {
+            if ((p & 3L) == 3L) {
+                sift(array, pshift, head);
+                p >>>= 2;
+                pshift += 2;
+            } else {
+                // Add a new singleton tree; if it will not be merged anymore, we must fully trinkle.
+                if (LEONARDO[pshift - 1] >= last - head) {
+                    trinkle(array, p, pshift, head, false);
+                } else {
+                    // This tree will be merged later, so it is enough to restore its internal heap property.
+                    sift(array, pshift, head);
+                }
+
+                if (pshift == 1) {
+                    // If L(1) is used, the new singleton is L(0).
+                    p <<= 1;
+                    pshift = 0;
+                } else {
+                    // Otherwise, shift to order 1 and append a singleton of order 1.
+                    p <<= (pshift - 1);
+                    pshift = 1;
+                }
+            }
+
+            p |= 1L;
+            head++;
+        }
+
+        trinkle(array, p, pshift, head, false);
+
+        // Repeatedly remove the maximum (always at head) by shrinking the heap region.
+        while (pshift != 1 || p != 1L) {
+            if (pshift <= 1) {
+                // Rightmost tree is a singleton (order 0 or 1). Move to the previous tree root.
+                final long mask = p & ~1L;
+                final int shift = Long.numberOfTrailingZeros(mask);
+                p >>>= shift;
+                pshift += shift;
+            } else {
+                // Split a tree of order (pshift) into two children trees of orders (pshift-1) and (pshift-2).
+                p <<= 2;
+                p ^= 7L;
+                pshift -= 2;
+
+                trinkle(array, p >>> 1, pshift + 1, head - LEONARDO[pshift] - 1, true);
+                trinkle(array, p, pshift, head - 1, true);
+            }
+
+            head--;
+        }
+
+        return array;
+    }
+
+    private static <T extends Comparable<T>> void sift(final T[] array, int order, int root) {
+        final T value = array[root];
+
+        while (order > 1) {
+            final int right = root - 1;
+            final int left = root - 1 - LEONARDO[order - 2];
+
+            if (!SortUtils.less(value, array[left]) && !SortUtils.less(value, array[right])) {
+                break;
+            }
+
+            if (!SortUtils.less(array[left], array[right])) {
+                array[root] = array[left];
+                root = left;
+                order -= 1;
+            } else {
+                array[root] = array[right];
+                root = right;
+                order -= 2;
+            }
+        }
+
+        array[root] = value;
+    }
+
+    private static <T extends Comparable<T>> void trinkle(final T[] array, long p, int order, int root, boolean trusty) {
+        final T value = array[root];
+
+        while (p != 1L) {
+            final int stepson = root - LEONARDO[order];
+
+            if (!SortUtils.less(value, array[stepson])) {
+                break;
+            }
+
+            if (!trusty && order > 1) {
+                final int right = root - 1;
+                final int left = root - 1 - LEONARDO[order - 2];
+
+                if (!SortUtils.less(array[right], array[stepson]) || !SortUtils.less(array[left], array[stepson])) {
+                    break;
+                }
+            }
+
+            array[root] = array[stepson];
+            root = stepson;
+
+            final long mask = p & ~1L;
+            final int shift = Long.numberOfTrailingZeros(mask);
+            p >>>= shift;
+            order += shift;
+            trusty = false;
+        }
+
+        if (!trusty) {
+            array[root] = value;
+            sift(array, order, root);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/SmoothSortTest.java b/src/test/java/com/thealgorithms/sorts/SmoothSortTest.java
new file mode 100644
index 000000000000..8df0502e80e7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/SmoothSortTest.java
@@ -0,0 +1,8 @@
+package com.thealgorithms.sorts;
+
+public class SmoothSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new SmoothSort();
+    }
+}

From 1644db2a3449d3a82dfd96ad25a98d7489adcf54 Mon Sep 17 00:00:00 2001
From: Tarunj Gupta <145449390+tarunjgupta@users.noreply.github.com>
Date: Sat, 10 Jan 2026 21:02:19 +0530
Subject: [PATCH 1155/1338] Add Count Nice Subarrays sliding using window
 algorithm (#7206)

* Add Count Nice Subarrays sliding window algorithm

* Add detailed comments and reference to CountNiceSubarrays

* Fix clang-format issues in CountNiceSubarrays

* Added extra edge cases

* changes made
---
 .../slidingwindow/CountNiceSubarrays.java     | 99 +++++++++++++++++++
 .../slidingwindow/CountNiceSubarraysTest.java | 55 +++++++++++
 2 files changed, 154 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/slidingwindow/CountNiceSubarrays.java
 create mode 100644 src/test/java/com/thealgorithms/slidingwindow/CountNiceSubarraysTest.java

diff --git a/src/main/java/com/thealgorithms/slidingwindow/CountNiceSubarrays.java b/src/main/java/com/thealgorithms/slidingwindow/CountNiceSubarrays.java
new file mode 100644
index 000000000000..46f8deeb58dd
--- /dev/null
+++ b/src/main/java/com/thealgorithms/slidingwindow/CountNiceSubarrays.java
@@ -0,0 +1,99 @@
+package com.thealgorithms.slidingwindow;
+
+/**
+ * Counts the number of "nice subarrays".
+ * A nice subarray is a contiguous subarray that contains exactly k odd numbers.
+ *
+ * This implementation uses the sliding window technique.
+ *
+ * Reference:
+ * https://leetcode.com/problems/count-number-of-nice-subarrays/
+ *
+ * Time Complexity: O(n)
+ * Space Complexity: O(n)
+ */
+public final class CountNiceSubarrays {
+
+    // Private constructor to prevent instantiation
+    private CountNiceSubarrays() {
+    }
+
+    /**
+     * Returns the count of subarrays containing exactly k odd numbers.
+     *
+     * @param nums input array of integers
+     * @param k    number of odd elements required in the subarray
+     * @return number of nice subarrays
+     */
+    public static int countNiceSubarrays(int[] nums, int k) {
+
+        int n = nums.length;
+
+        // Left pointer of the sliding window
+        int left = 0;
+
+        // Tracks number of odd elements in the current window
+        int oddCount = 0;
+
+        // Final answer: total number of nice subarrays
+        int result = 0;
+
+        /*
+         * memo[i] stores how many valid starting positions exist
+         * when the left pointer is at index i.
+         *
+         * This avoids recomputing the same values again.
+         */
+        int[] memo = new int[n];
+
+        // Right pointer moves forward to expand the window
+        for (int right = 0; right < n; right++) {
+
+            // If current element is odd, increment odd count
+            if ((nums[right] & 1) == 1) {
+                oddCount++;
+            }
+
+            /*
+             * If oddCount exceeds k, shrink the window from the left
+             * until oddCount becomes valid again.
+             */
+            if (oddCount > k) {
+                left += memo[left];
+                oddCount--;
+            }
+
+            /*
+             * When the window contains exactly k odd numbers,
+             * count all possible valid subarrays starting at `left`.
+             */
+            if (oddCount == k) {
+
+                /*
+                 * If this left index hasn't been processed before,
+                 * count how many consecutive even numbers follow it.
+                 */
+                if (memo[left] == 0) {
+                    int count = 0;
+                    int temp = left;
+
+                    // Count consecutive even numbers
+                    while ((nums[temp] & 1) == 0) {
+                        count++;
+                        temp++;
+                    }
+
+                    /*
+                     * Number of valid subarrays starting at `left`
+                     * is (count of even numbers + 1)
+                     */
+                    memo[left] = count + 1;
+                }
+
+                // Add number of valid subarrays for this left position
+                result += memo[left];
+            }
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/slidingwindow/CountNiceSubarraysTest.java b/src/test/java/com/thealgorithms/slidingwindow/CountNiceSubarraysTest.java
new file mode 100644
index 000000000000..71bf24cc9e30
--- /dev/null
+++ b/src/test/java/com/thealgorithms/slidingwindow/CountNiceSubarraysTest.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.slidingwindow;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class CountNiceSubarraysTest {
+    @Test
+    void testExampleCase() {
+        int[] nums = {1, 1, 2, 1, 1};
+        assertEquals(2, CountNiceSubarrays.countNiceSubarrays(nums, 3));
+    }
+
+    @Test
+    void testAllEvenNumbers() {
+        int[] nums = {2, 4, 6, 8};
+        assertEquals(0, CountNiceSubarrays.countNiceSubarrays(nums, 1));
+    }
+
+    @Test
+    void testSingleOdd() {
+        int[] nums = {1};
+        assertEquals(1, CountNiceSubarrays.countNiceSubarrays(nums, 1));
+    }
+
+    @Test
+    void testMultipleChoices() {
+        int[] nums = {2, 2, 1, 2, 2, 1, 2};
+        assertEquals(6, CountNiceSubarrays.countNiceSubarrays(nums, 2));
+    }
+
+    @Test
+    void testTrailingEvenNumbers() {
+        int[] nums = {1, 2, 2, 2};
+        assertEquals(4, CountNiceSubarrays.countNiceSubarrays(nums, 1));
+    }
+
+    @Test
+    void testMultipleWindowShrinks() {
+        int[] nums = {1, 1, 1, 1};
+        assertEquals(3, CountNiceSubarrays.countNiceSubarrays(nums, 2));
+    }
+
+    @Test
+    void testEvensBetweenOdds() {
+        int[] nums = {2, 1, 2, 1, 2};
+        assertEquals(4, CountNiceSubarrays.countNiceSubarrays(nums, 2));
+    }
+
+    @Test
+    void testShrinkWithTrailingEvens() {
+        int[] nums = {2, 2, 1, 2, 2, 1, 2, 2};
+        assertEquals(9, CountNiceSubarrays.countNiceSubarrays(nums, 2));
+    }
+}

From bdda4fa6b49c94087caab1021d680aa78a50d7e1 Mon Sep 17 00:00:00 2001
From: asmitha-16 <asmitha162005@gmail.com>
Date: Wed, 14 Jan 2026 03:09:41 +0530
Subject: [PATCH 1156/1338] Handle negative input in perfect square checks
 (#7207)

---
 src/main/java/com/thealgorithms/maths/PerfectSquare.java | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/main/java/com/thealgorithms/maths/PerfectSquare.java b/src/main/java/com/thealgorithms/maths/PerfectSquare.java
index e9318bd7d805..aec43062121a 100644
--- a/src/main/java/com/thealgorithms/maths/PerfectSquare.java
+++ b/src/main/java/com/thealgorithms/maths/PerfectSquare.java
@@ -15,6 +15,9 @@ private PerfectSquare() {
      * <tt>false</tt>
      */
     public static boolean isPerfectSquare(final int number) {
+        if (number < 0) {
+            return false;
+        }
         final int sqrt = (int) Math.sqrt(number);
         return sqrt * sqrt == number;
     }
@@ -27,6 +30,9 @@ public static boolean isPerfectSquare(final int number) {
      * {@code false}
      */
     public static boolean isPerfectSquareUsingPow(long number) {
+        if (number < 0) {
+            return false;
+        }
         long a = (long) Math.pow(number, 1.0 / 2);
         return a * a == number;
     }

From 7148661e44bb4b27d29f63771ef205235f42192a Mon Sep 17 00:00:00 2001
From: Ahmed Allam <60698204+GziXnine@users.noreply.github.com>
Date: Wed, 14 Jan 2026 00:04:14 +0200
Subject: [PATCH 1157/1338] Feat/tournament sort (#7201)

* feat: implement Smooth Sort algorithm with detailed JavaDoc and test class

* style: format LEONARDO array for improved readability with clang-format

* feat(sorts): add TournamentSort (winner-tree)

* test: add unit test for null array handling in TournamentSort

---------

Co-authored-by: Ahmed Allam <60698204+AllamF5J@users.noreply.github.com>
Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Co-authored-by: Oleksandr Klymenko <19151554+alxkm@users.noreply.github.com>
---
 .../thealgorithms/sorts/TournamentSort.java   | 84 +++++++++++++++++++
 .../sorts/TournamentSortTest.java             | 19 +++++
 2 files changed, 103 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/TournamentSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/TournamentSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/TournamentSort.java b/src/main/java/com/thealgorithms/sorts/TournamentSort.java
new file mode 100644
index 000000000000..ec51a1e2c0a9
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/TournamentSort.java
@@ -0,0 +1,84 @@
+package com.thealgorithms.sorts;
+
+import java.util.Arrays;
+
+/**
+ * Tournament Sort algorithm implementation.
+ *
+ * Tournament sort builds a winner tree (a complete binary tree storing the index
+ * of the smallest element in each subtree). It then repeatedly extracts the
+ * winner (minimum) and updates the path from the removed leaf to the root.
+ *
+ * Time Complexity:
+ * - Best case: O(n log n)
+ * - Average case: O(n log n)
+ * - Worst case: O(n log n)
+ *
+ * Space Complexity: O(n) – additional winner-tree storage
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Tournament_sort">Tournament Sort Algorithm</a>
+ * @see SortAlgorithm
+ */
+public class TournamentSort implements SortAlgorithm {
+
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array == null || array.length < 2) {
+            return array;
+        }
+
+        final int n = array.length;
+        final int leafCount = nextPowerOfTwo(n);
+
+        // Winner tree represented as an array:
+        // - Leaves live at [leafCount .. 2*leafCount)
+        // - Internal nodes live at [1 .. leafCount)
+        // Each node stores an index into the original array or -1 for "empty".
+        final int[] tree = new int[2 * leafCount];
+        Arrays.fill(tree, -1);
+
+        for (int i = 0; i < n; i++) {
+            tree[leafCount + i] = i;
+        }
+
+        for (int node = leafCount - 1; node >= 1; node--) {
+            tree[node] = winnerIndex(array, tree[node * 2], tree[node * 2 + 1]);
+        }
+
+        final T[] result = array.clone();
+        for (int out = 0; out < n; out++) {
+            final int winner = tree[1];
+            result[out] = array[winner];
+
+            int node = leafCount + winner;
+            tree[node] = -1;
+
+            for (node /= 2; node >= 1; node /= 2) {
+                tree[node] = winnerIndex(array, tree[node * 2], tree[node * 2 + 1]);
+            }
+        }
+
+        System.arraycopy(result, 0, array, 0, n);
+        return array;
+    }
+
+    private static int nextPowerOfTwo(int n) {
+        int power = 1;
+        while (power < n) {
+            power <<= 1;
+        }
+        return power;
+    }
+
+    private static <T extends Comparable<T>> int winnerIndex(T[] array, int leftIndex, int rightIndex) {
+        if (leftIndex == -1) {
+            return rightIndex;
+        }
+        if (rightIndex == -1) {
+            return leftIndex;
+        }
+
+        // If equal, prefer the left element to keep ordering deterministic.
+        return SortUtils.less(array[rightIndex], array[leftIndex]) ? rightIndex : leftIndex;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/TournamentSortTest.java b/src/test/java/com/thealgorithms/sorts/TournamentSortTest.java
new file mode 100644
index 000000000000..91da746447a8
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/TournamentSortTest.java
@@ -0,0 +1,19 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+public class TournamentSortTest extends SortingAlgorithmTest {
+
+    @Test
+    void shouldAcceptWhenNullArrayIsPassed() {
+        Integer[] array = null;
+        assertNull(getSortAlgorithm().sort(array));
+    }
+
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new TournamentSort();
+    }
+}

From 66f76eb3d920f7a025aaca71ccc6c84da4287658 Mon Sep 17 00:00:00 2001
From: Ahmed Allam <60698204+GziXnine@users.noreply.github.com>
Date: Wed, 14 Jan 2026 11:59:25 +0200
Subject: [PATCH 1158/1338] Add RotatedBinarySearch (search in rotated sorted
 array) (#7202)

* feat: implement Smooth Sort algorithm with detailed JavaDoc and test class

* style: format LEONARDO array for improved readability with clang-format

* feat(sorts): add TournamentSort (winner-tree)

* test: add unit test for null array handling in TournamentSort

* feat(search): add rotated binary search

* test: add unit test for handling middle element in right sorted half of rotated array

---------

Co-authored-by: Ahmed Allam <60698204+AllamF5J@users.noreply.github.com>
---
 .../searches/RotatedBinarySearch.java         | 60 +++++++++++++++++++
 .../searches/RotatedBinarySearchTest.java     | 53 ++++++++++++++++
 2 files changed, 113 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/searches/RotatedBinarySearch.java
 create mode 100644 src/test/java/com/thealgorithms/searches/RotatedBinarySearchTest.java

diff --git a/src/main/java/com/thealgorithms/searches/RotatedBinarySearch.java b/src/main/java/com/thealgorithms/searches/RotatedBinarySearch.java
new file mode 100644
index 000000000000..86099b2fa2fa
--- /dev/null
+++ b/src/main/java/com/thealgorithms/searches/RotatedBinarySearch.java
@@ -0,0 +1,60 @@
+package com.thealgorithms.searches;
+
+import com.thealgorithms.devutils.searches.SearchAlgorithm;
+
+/**
+ * Searches for a key in a sorted array that has been rotated at an unknown pivot.
+ *
+ * <p>
+ * Example:
+ * {@code [8, 9, 10, 1, 2, 3, 4, 5, 6, 7]}
+ *
+ * <p>
+ * This is a modified binary search. When the array contains no duplicates, the
+ * time complexity is {@code O(log n)}. With duplicates, the algorithm still
+ * works but may degrade to {@code O(n)} in the worst case.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Search_in_rotated_sorted_array">Search in rotated sorted array</a>
+ * @see SearchAlgorithm
+ */
+public final class RotatedBinarySearch implements SearchAlgorithm {
+
+    @Override
+    public <T extends Comparable<T>> int find(T[] array, T key) {
+        int left = 0;
+        int right = array.length - 1;
+
+        while (left <= right) {
+            int middle = (left + right) >>> 1;
+            int cmp = key.compareTo(array[middle]);
+            if (cmp == 0) {
+                return middle;
+            }
+
+            // Handle duplicates: if we cannot determine which side is sorted.
+            if (array[left].compareTo(array[middle]) == 0 && array[middle].compareTo(array[right]) == 0) {
+                left++;
+                right--;
+                continue;
+            }
+
+            // Left half is sorted.
+            if (array[left].compareTo(array[middle]) <= 0) {
+                if (array[left].compareTo(key) <= 0 && key.compareTo(array[middle]) < 0) {
+                    right = middle - 1;
+                } else {
+                    left = middle + 1;
+                }
+            } else {
+                // Right half is sorted.
+                if (array[middle].compareTo(key) < 0 && key.compareTo(array[right]) <= 0) {
+                    left = middle + 1;
+                } else {
+                    right = middle - 1;
+                }
+            }
+        }
+
+        return -1;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/searches/RotatedBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/RotatedBinarySearchTest.java
new file mode 100644
index 000000000000..1e6ab4c37fcc
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/RotatedBinarySearchTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class RotatedBinarySearchTest {
+
+    @Test
+    void shouldFindElementInRotatedArrayLeftSide() {
+        RotatedBinarySearch search = new RotatedBinarySearch();
+        Integer[] array = {8, 9, 10, 11, 12, 1, 2, 3, 4, 5, 6, 7};
+        assertEquals(2, search.find(array, 10));
+    }
+
+    @Test
+    void shouldFindElementInRotatedArrayRightSide() {
+        RotatedBinarySearch search = new RotatedBinarySearch();
+        Integer[] array = {8, 9, 10, 11, 12, 1, 2, 3, 4, 5, 6, 7};
+        assertEquals(6, search.find(array, 2));
+    }
+
+    @Test
+    void shouldFindElementInNotRotatedArray() {
+        RotatedBinarySearch search = new RotatedBinarySearch();
+        Integer[] array = {1, 2, 3, 4, 5, 6, 7};
+        assertEquals(4, search.find(array, 5));
+    }
+
+    @Test
+    void shouldReturnMinusOneWhenNotFound() {
+        RotatedBinarySearch search = new RotatedBinarySearch();
+        Integer[] array = {4, 5, 6, 7, 0, 1, 2};
+        assertEquals(-1, search.find(array, 3));
+    }
+
+    @Test
+    void shouldHandleWhenMiddleIsGreaterThanKeyInRightSortedHalf() {
+        RotatedBinarySearch search = new RotatedBinarySearch();
+        Integer[] array = {6, 7, 0, 1, 2, 3, 4, 5};
+        assertEquals(2, search.find(array, 0));
+    }
+
+    @Test
+    void shouldHandleDuplicates() {
+        RotatedBinarySearch search = new RotatedBinarySearch();
+        Integer[] array = {2, 2, 2, 3, 4, 2};
+        int index = search.find(array, 3);
+        assertTrue(index >= 0 && index < array.length);
+        assertEquals(3, array[index]);
+    }
+}

From babc762478f94491209999ed120538be6b863d80 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 15 Jan 2026 23:24:40 +0100
Subject: [PATCH 1159/1338] chore(deps-dev): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.7.2 to 7.7.3 (#7211)

chore(deps-dev): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.7.2 to 7.7.3.
- [Commits](https://github.com/mebigfatguy/fb-contrib/compare/v7.7.2...v7.7.3)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.7.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index d3db730327d3..a685e334460c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -127,7 +127,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.7.2</version>
+                            <version>7.7.3</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

From fd0bcb79e61743e96e837a48e2fc9a54efd08a42 Mon Sep 17 00:00:00 2001
From: Ahmed Allam <60698204+GziXnine@users.noreply.github.com>
Date: Fri, 16 Jan 2026 13:33:29 +0200
Subject: [PATCH 1160/1338] Add Middle of Linked List (Slow/Fast Pointers)
 (#7212)

* feat: implement Smooth Sort algorithm with detailed JavaDoc and test class

* style: format LEONARDO array for improved readability with clang-format

* feat: add MiddleOfLinkedList class and corresponding test cases

* docs: update documentation for MiddleOfLinkedList class

* test: refactor MiddleOfLinkedListTest to improve readability and assertions

* test: refactor MiddleOfLinkedListTest for improved null safety and readability

---------

Co-authored-by: Ahmed Allam <60698204+AllamF5J@users.noreply.github.com>
---
 .../lists/MiddleOfLinkedList.java             | 46 ++++++++++++
 .../lists/MiddleOfLinkedListTest.java         | 74 +++++++++++++++++++
 2 files changed, 120 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/lists/MiddleOfLinkedList.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/MiddleOfLinkedListTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/MiddleOfLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/MiddleOfLinkedList.java
new file mode 100644
index 000000000000..0ee788db2ff9
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/lists/MiddleOfLinkedList.java
@@ -0,0 +1,46 @@
+package com.thealgorithms.datastructures.lists;
+
+/**
+ * Returns the middle node of a singly linked list using the two-pointer technique.
+ *
+ * <p>The {@code slow} pointer advances by one node per iteration while {@code fast} advances by two.
+ * When {@code fast == null} or {@code fast.next == null}, {@code slow} points to the middle node.
+ * For even-length lists, this returns the <em>second</em> middle node.</p>
+ *
+ * <p>This method does not modify the input list.</p>
+ *
+ * <p>Reference: https://en.wikipedia.org/wiki/Cycle_detection#Floyd's_tortoise_and_hare</p>
+ *
+ * <p>Complexity:</p>
+ * <ul>
+ *   <li>Time: {@code O(n)}</li>
+ *   <li>Space: {@code O(1)}</li>
+ * </ul>
+ */
+public final class MiddleOfLinkedList {
+
+    private MiddleOfLinkedList() {
+    }
+
+    /**
+     * Returns the middle node of the list.
+     *
+     * @param head the head of the singly linked list; may be {@code null}
+     * @return the middle node (second middle for even-sized lists), or {@code null} if {@code head} is {@code null}
+     */
+    public static SinglyLinkedListNode middleNode(final SinglyLinkedListNode head) {
+        if (head == null) {
+            return null;
+        }
+
+        SinglyLinkedListNode slow = head;
+        SinglyLinkedListNode fast = head;
+
+        while (fast != null && fast.next != null) {
+            slow = slow.next;
+            fast = fast.next.next;
+        }
+
+        return slow;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/MiddleOfLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/MiddleOfLinkedListTest.java
new file mode 100644
index 000000000000..ba5614a07916
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/MiddleOfLinkedListTest.java
@@ -0,0 +1,74 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import java.util.Objects;
+import org.junit.jupiter.api.Test;
+
+public class MiddleOfLinkedListTest {
+
+    private static SinglyLinkedListNode listOf(int firstValue, int... remainingValues) {
+        SinglyLinkedListNode head = new SinglyLinkedListNode(firstValue);
+        SinglyLinkedListNode current = head;
+
+        for (int i = 0; i < remainingValues.length; i++) {
+            current.next = new SinglyLinkedListNode(remainingValues[i]);
+            current = current.next;
+        }
+        return head;
+    }
+
+    @Test
+    void middleNodeOddLength() {
+        SinglyLinkedListNode head = listOf(1, 2, 3, 4, 5);
+        SinglyLinkedListNode middle = Objects.requireNonNull(MiddleOfLinkedList.middleNode(head));
+        assertEquals(3, middle.value);
+    }
+
+    @Test
+    void middleNodeEvenLengthReturnsSecondMiddle() {
+        SinglyLinkedListNode head = listOf(1, 2, 3, 4, 5, 6);
+        SinglyLinkedListNode middle = Objects.requireNonNull(MiddleOfLinkedList.middleNode(head));
+        assertEquals(4, middle.value);
+    }
+
+    @Test
+    void middleNodeSingleElement() {
+        SinglyLinkedListNode head = listOf(42);
+        SinglyLinkedListNode middle = Objects.requireNonNull(MiddleOfLinkedList.middleNode(head));
+        assertEquals(42, middle.value);
+    }
+
+    @Test
+    void middleNodeTwoElementsReturnsSecond() {
+        SinglyLinkedListNode head = listOf(10, 20);
+        SinglyLinkedListNode middle = Objects.requireNonNull(MiddleOfLinkedList.middleNode(head));
+        assertEquals(20, middle.value);
+    }
+
+    @Test
+    void middleNodeNullHead() {
+        assertNull(MiddleOfLinkedList.middleNode(null));
+    }
+
+    @Test
+    void middleNodeDoesNotModifyListStructure() {
+        SinglyLinkedListNode first = new SinglyLinkedListNode(1);
+        SinglyLinkedListNode second = new SinglyLinkedListNode(2);
+        SinglyLinkedListNode third = new SinglyLinkedListNode(3);
+        SinglyLinkedListNode fourth = new SinglyLinkedListNode(4);
+
+        first.next = second;
+        second.next = third;
+        third.next = fourth;
+
+        SinglyLinkedListNode middle = Objects.requireNonNull(MiddleOfLinkedList.middleNode(first));
+        assertEquals(3, middle.value);
+
+        assertEquals(second, first.next);
+        assertEquals(third, second.next);
+        assertEquals(fourth, third.next);
+        assertNull(fourth.next);
+    }
+}

From 782d0755d584c9f5c9931ff6f03976144e10c279 Mon Sep 17 00:00:00 2001
From: SwaatiR <85189166+SwaatiR@users.noreply.github.com>
Date: Sat, 17 Jan 2026 23:48:54 +0530
Subject: [PATCH 1161/1338] Improve documentation for Linear Search algorithm
 (#7214)

---
 .../thealgorithms/searches/LinearSearch.java  | 23 +++++++++++--------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/LinearSearch.java b/src/main/java/com/thealgorithms/searches/LinearSearch.java
index c7b70edb5112..cb483d8dfedc 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearch.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearch.java
@@ -1,21 +1,26 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
-
 /**
- * Linear search is the easiest search algorithm It works with sorted and
- * unsorted arrays (an binary search works only with sorted array) This
- * algorithm just compares all elements of an array to find a value
+ * Linear Search is a simple searching algorithm that checks
+ * each element of the array sequentially until the target
+ * value is found or the array ends.
+ *
+ * It works for both sorted and unsorted arrays.
  *
- * <p>
- * Worst-case performance O(n) Best-case performance O(1) Average performance
- * O(n) Worst-case space complexity
+ * Time Complexity:
+ *  - Best case: O(1)
+ *  - Average case: O(n)
+ *  - Worst case: O(n)
  *
- * @author Varun Upadhyay (https://github.com/varunu28)
- * @author Podshivalov Nikita (https://github.com/nikitap492)
+ * Space Complexity: O(1)
+ *
+ * @author Varun Upadhyay
+ * @author Podshivalov Nikita
  * @see BinarySearch
  * @see SearchAlgorithm
  */
+
 public class LinearSearch implements SearchAlgorithm {
 
     /**

From 48f6322b385f12e8b052d1e04e7d1acdd765b982 Mon Sep 17 00:00:00 2001
From: Chahat Sandhu <s.chahatpreet@icloud.com>
Date: Sat, 17 Jan 2026 12:22:11 -0600
Subject: [PATCH 1162/1338] docs: add Javadoc to FibonacciSeries (#7215)

* docs: add Javadoc to FibonacciSeries

* fix: make small adjustment

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../recursion/FibonacciSeries.java            | 22 ++++++++++++++-----
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java b/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
index 9bc6da2f7443..9c809858099e 100644
--- a/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
+++ b/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
@@ -1,16 +1,26 @@
 package com.thealgorithms.recursion;
 
-/*
-    The Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones,
-    starting with 0 and 1.
-       NUMBER    0 1 2 3 4 5 6 7  8  9  10 ...
-       FIBONACCI 0 1 1 2 3 5 8 13 21 34 55 ...
-*/
+/**
+ * The Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones,
+ * starting with 0 and 1.
+ * <p>
+ * Example:
+ * 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 ...
+ * </p>
+ */
 
 public final class FibonacciSeries {
     private FibonacciSeries() {
         throw new UnsupportedOperationException("Utility class");
     }
+
+    /**
+     * Calculates the nth term in the Fibonacci sequence using recursion.
+     *
+     * @param n the position in the Fibonacci sequence (must be non-negative)
+     * @return the nth Fibonacci number
+     * @throws IllegalArgumentException if n is negative
+     */
     public static int fibonacci(int n) {
         if (n < 0) {
             throw new IllegalArgumentException("n must be a non-negative integer");

From 79cdb98193cb34fa32d9bbad06c21a0d0f356bb3 Mon Sep 17 00:00:00 2001
From: SwaatiR <85189166+SwaatiR@users.noreply.github.com>
Date: Sun, 18 Jan 2026 21:31:01 +0530
Subject: [PATCH 1163/1338] Add input validation and clarify sorted array
 requirement in Binary Search (#7216)

Added input validation and clarify sorted array rrequirement in Binary Search
---
 src/main/java/com/thealgorithms/searches/BinarySearch.java | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/BinarySearch.java b/src/main/java/com/thealgorithms/searches/BinarySearch.java
index bedad1667f33..0cac484d56b4 100644
--- a/src/main/java/com/thealgorithms/searches/BinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/BinarySearch.java
@@ -5,7 +5,9 @@
 /**
  * Binary search is one of the most popular algorithms The algorithm finds the
  * position of a target value within a sorted array
- *
+ * IMPORTANT
+ * This algorithm works correctly only if the input array is sorted
+ * in ascending order.
  * <p>
  * Worst-case performance O(log n) Best-case performance O(1) Average
  * performance O(log n) Worst-case space complexity O(1)
@@ -25,6 +27,9 @@ class BinarySearch implements SearchAlgorithm {
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
+        if (array == null || array.length == 0) {
+            return -1;
+        }
         return search(array, key, 0, array.length - 1);
     }
 

From 1b9373e71a9a3e8e9f1b4f3f2338aee419ee2c1e Mon Sep 17 00:00:00 2001
From: Chahat Sandhu <s.chahatpreet@icloud.com>
Date: Mon, 19 Jan 2026 03:59:58 -0600
Subject: [PATCH 1164/1338] feat: add Bell Numbers algorithm using Aitken's
 Array (#7219)

* feat: added Bell Numbers algorithm using Aitken's Array

* style: applied clang-format fixes
---
 .../com/thealgorithms/maths/BellNumbers.java  | 59 +++++++++++++++++++
 .../thealgorithms/maths/BellNumbersTest.java  | 53 +++++++++++++++++
 2 files changed, 112 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/BellNumbers.java
 create mode 100644 src/test/java/com/thealgorithms/maths/BellNumbersTest.java

diff --git a/src/main/java/com/thealgorithms/maths/BellNumbers.java b/src/main/java/com/thealgorithms/maths/BellNumbers.java
new file mode 100644
index 000000000000..d4dc1014f48b
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/BellNumbers.java
@@ -0,0 +1,59 @@
+package com.thealgorithms.maths;
+
+/**
+ * The Bell numbers count the number of partitions of a set.
+ * The n-th Bell number is the number of ways a set of n elements can be partitioned
+ * into nonempty subsets.
+ *
+ * <p>
+ * This implementation uses the Bell Triangle (Aitken's array) method.
+ * Time Complexity: O(n^2)
+ * Space Complexity: O(n^2)
+ * </p>
+ *
+ * @author Chahat Sandhu, <a href="https://github.com/singhc7">singhc7</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Bell_number">Bell Number (Wikipedia)</a>
+ */
+public final class BellNumbers {
+
+    private BellNumbers() {
+    }
+
+    /**
+     * Calculates the n-th Bell number using the Bell Triangle.
+     *
+     * @param n the index of the Bell number (must be non-negative)
+     * @return the n-th Bell number
+     * @throws IllegalArgumentException if n is negative or n > 25
+     */
+    public static long compute(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("n must be non-negative");
+        }
+        if (n == 0) {
+            return 1;
+        }
+        if (n > 25) {
+            throw new IllegalArgumentException("n must be <= 25. For larger n, use BigInteger implementation.");
+        }
+
+        // We use a 2D array to visualize the Bell Triangle
+        long[][] bellTriangle = new long[n + 1][n + 1];
+
+        // Base case: The triangle starts with 1
+        bellTriangle[0][0] = 1;
+
+        for (int i = 1; i <= n; i++) {
+            // Rule 1: The first number in a new row is the LAST number of the previous row
+            bellTriangle[i][0] = bellTriangle[i - 1][i - 1];
+
+            // Rule 2: Fill the rest of the row by adding the previous neighbor and the upper-left neighbor
+            for (int j = 1; j <= i; j++) {
+                bellTriangle[i][j] = bellTriangle[i][j - 1] + bellTriangle[i - 1][j - 1];
+            }
+        }
+
+        // The Bell number B_n is the first number in the n-th row
+        return bellTriangle[n][0];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/BellNumbersTest.java b/src/test/java/com/thealgorithms/maths/BellNumbersTest.java
new file mode 100644
index 000000000000..8dd83cf0f7a9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/BellNumbersTest.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class BellNumbersTest {
+
+    @Test
+    void testStandardCases() {
+        // Base cases and small numbers
+        assertEquals(1, BellNumbers.compute(0));
+        assertEquals(1, BellNumbers.compute(1));
+        assertEquals(2, BellNumbers.compute(2));
+        assertEquals(5, BellNumbers.compute(3));
+        assertEquals(15, BellNumbers.compute(4));
+        assertEquals(52, BellNumbers.compute(5));
+    }
+
+    @Test
+    void testMediumNumber() {
+        // B10 = 115,975
+        assertEquals(115975, BellNumbers.compute(10));
+        // B15 = 1,382,958,545
+        assertEquals(1382958545L, BellNumbers.compute(15));
+    }
+
+    @Test
+    void testLargeNumber() {
+        // B20 = 51,724,158,235,372
+        // We use the 'L' suffix to tell Java this is a long literal
+        assertEquals(51724158235372L, BellNumbers.compute(20));
+    }
+
+    @Test
+    void testMaxLongCapacity() {
+        // B25 is the largest Bell number that fits in a Java long (signed 64-bit)
+        // B25 = 4,638,590,332,229,999,353
+        assertEquals(4638590332229999353L, BellNumbers.compute(25));
+    }
+
+    @Test
+    void testNegativeInput() {
+        assertThrows(IllegalArgumentException.class, () -> BellNumbers.compute(-1));
+    }
+
+    @Test
+    void testOverflowProtection() {
+        // We expect an exception if the user asks for the impossible
+        assertThrows(IllegalArgumentException.class, () -> BellNumbers.compute(26));
+    }
+}

From 109ed2e49743df52cb6aad1a5cfc496432ae3d10 Mon Sep 17 00:00:00 2001
From: Chahat Sandhu <s.chahatpreet@icloud.com>
Date: Mon, 19 Jan 2026 04:15:59 -0600
Subject: [PATCH 1165/1338] feat: Add Prefix Sum category with 1D and 2D
 implementations (#7220)

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../thealgorithms/prefixsum/PrefixSum.java    | 54 +++++++++++
 .../thealgorithms/prefixsum/PrefixSum2D.java  | 64 +++++++++++++
 .../prefixsum/PrefixSum2DTest.java            | 92 +++++++++++++++++++
 .../prefixsum/PrefixSumTest.java              | 80 ++++++++++++++++
 4 files changed, 290 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/prefixsum/PrefixSum.java
 create mode 100644 src/main/java/com/thealgorithms/prefixsum/PrefixSum2D.java
 create mode 100644 src/test/java/com/thealgorithms/prefixsum/PrefixSum2DTest.java
 create mode 100644 src/test/java/com/thealgorithms/prefixsum/PrefixSumTest.java

diff --git a/src/main/java/com/thealgorithms/prefixsum/PrefixSum.java b/src/main/java/com/thealgorithms/prefixsum/PrefixSum.java
new file mode 100644
index 000000000000..47f6366e2924
--- /dev/null
+++ b/src/main/java/com/thealgorithms/prefixsum/PrefixSum.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.prefixsum;
+
+/**
+ * A class that implements the Prefix Sum algorithm.
+ *
+ * <p>Prefix Sum is a technique used to preprocess an array such that
+ * range sum queries can be answered in O(1) time.
+ * The preprocessing step takes O(N) time.
+ *
+ * <p>This implementation uses a long array for the prefix sums to prevent
+ * integer overflow when the sum of elements exceeds Integer.MAX_VALUE.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Prefix_sum">Prefix Sum (Wikipedia)</a>
+ * @author Chahat Sandhu, <a href="https://github.com/singhc7">singhc7</a>
+ */
+public class PrefixSum {
+
+    private final long[] prefixSums;
+
+    /**
+     * Constructor to preprocess the input array.
+     *
+     * @param array The input integer array.
+     * @throws IllegalArgumentException if the array is null.
+     */
+    public PrefixSum(int[] array) {
+        if (array == null) {
+            throw new IllegalArgumentException("Input array cannot be null");
+        }
+        this.prefixSums = new long[array.length + 1];
+        this.prefixSums[0] = 0;
+
+        for (int i = 0; i < array.length; i++) {
+            // Automatically promotes int to long during addition
+            this.prefixSums[i + 1] = this.prefixSums[i] + array[i];
+        }
+    }
+
+    /**
+     * Calculates the sum of elements in the range [left, right].
+     * Indices are 0-based.
+     *
+     * @param left  The starting index (inclusive).
+     * @param right The ending index (inclusive).
+     * @return The sum of elements from index left to right as a long.
+     * @throws IndexOutOfBoundsException if indices are out of valid range.
+     */
+    public long sumRange(int left, int right) {
+        if (left < 0 || right >= prefixSums.length - 1 || left > right) {
+            throw new IndexOutOfBoundsException("Invalid range indices");
+        }
+        return prefixSums[right + 1] - prefixSums[left];
+    }
+}
diff --git a/src/main/java/com/thealgorithms/prefixsum/PrefixSum2D.java b/src/main/java/com/thealgorithms/prefixsum/PrefixSum2D.java
new file mode 100644
index 000000000000..9c168bc6bcc4
--- /dev/null
+++ b/src/main/java/com/thealgorithms/prefixsum/PrefixSum2D.java
@@ -0,0 +1,64 @@
+package com.thealgorithms.prefixsum;
+
+/**
+ * A class that implements the 2D Prefix Sum algorithm.
+ *
+ * <p>2D Prefix Sum is a technique used to preprocess a 2D matrix such that
+ * sub-matrix sum queries can be answered in O(1) time.
+ * The preprocessing step takes O(N*M) time.
+ *
+ * <p>This implementation uses a long array for the prefix sums to prevent
+ * integer overflow.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Summed-area_table">Summed-area table (Wikipedia)</a>
+ * @author Chahat Sandhu, <a href="https://github.com/singhc7">singhc7</a>
+ */
+public class PrefixSum2D {
+
+    private final long[][] prefixSums;
+
+    /**
+     * Constructor to preprocess the input matrix.
+     *
+     * @param matrix The input integer matrix.
+     * @throws IllegalArgumentException if the matrix is null or empty.
+     */
+    public PrefixSum2D(int[][] matrix) {
+        if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
+            throw new IllegalArgumentException("Input matrix cannot be null or empty");
+        }
+
+        int rows = matrix.length;
+        int cols = matrix[0].length;
+        this.prefixSums = new long[rows + 1][cols + 1];
+
+        for (int i = 0; i < rows; i++) {
+            for (int j = 0; j < cols; j++) {
+                // P[i+1][j+1] = current + above + left - diagonal_overlap
+                this.prefixSums[i + 1][j + 1] = matrix[i][j] + this.prefixSums[i][j + 1] + this.prefixSums[i + 1][j] - this.prefixSums[i][j];
+            }
+        }
+    }
+
+    /**
+     * Calculates the sum of the sub-matrix defined by (row1, col1) to (row2, col2).
+     * Indices are 0-based.
+     *
+     * @param row1 Top row index.
+     * @param col1 Left column index.
+     * @param row2 Bottom row index.
+     * @param col2 Right column index.
+     * @return The sum of the sub-matrix.
+     * @throws IndexOutOfBoundsException if indices are invalid.
+     */
+    public long sumRegion(int row1, int col1, int row2, int col2) {
+        if (row1 < 0 || row2 >= prefixSums.length - 1 || row2 < row1) {
+            throw new IndexOutOfBoundsException("Invalid row indices");
+        }
+        if (col1 < 0 || col2 >= prefixSums[0].length - 1 || col2 < col1) {
+            throw new IndexOutOfBoundsException("Invalid column indices");
+        }
+
+        return prefixSums[row2 + 1][col2 + 1] - prefixSums[row1][col2 + 1] - prefixSums[row2 + 1][col1] + prefixSums[row1][col1];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/prefixsum/PrefixSum2DTest.java b/src/test/java/com/thealgorithms/prefixsum/PrefixSum2DTest.java
new file mode 100644
index 000000000000..87feff859356
--- /dev/null
+++ b/src/test/java/com/thealgorithms/prefixsum/PrefixSum2DTest.java
@@ -0,0 +1,92 @@
+package com.thealgorithms.prefixsum;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class PrefixSum2DTest {
+
+    @Test
+    @DisplayName("Test basic 3x3 square matrix")
+    void testStandardSquare() {
+        int[][] matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+        PrefixSum2D ps = new PrefixSum2D(matrix);
+
+        // Sum of top-left 2x2: {1,2, 4,5} -> 12
+        assertEquals(12L, ps.sumRegion(0, 0, 1, 1));
+        // Sum of bottom-right 2x2: {5,6, 8,9} -> 28
+        assertEquals(28L, ps.sumRegion(1, 1, 2, 2));
+        // Full matrix -> 45
+        assertEquals(45L, ps.sumRegion(0, 0, 2, 2));
+    }
+
+    @Test
+    @DisplayName("Test rectangular matrix (more cols than rows)")
+    void testRectangularWide() {
+        int[][] matrix = {{1, 1, 1, 1}, {2, 2, 2, 2}};
+        PrefixSum2D ps = new PrefixSum2D(matrix);
+
+        // Sum of first 3 columns of both rows -> (1*3) + (2*3) = 9
+        assertEquals(9L, ps.sumRegion(0, 0, 1, 2));
+    }
+
+    @Test
+    @DisplayName("Test rectangular matrix (more rows than cols)")
+    void testRectangularTall() {
+        int[][] matrix = {{1}, {2}, {3}, {4}};
+        PrefixSum2D ps = new PrefixSum2D(matrix);
+
+        // Sum of middle two elements -> 2+3 = 5
+        assertEquals(5L, ps.sumRegion(1, 0, 2, 0));
+    }
+
+    @Test
+    @DisplayName("Test single element matrix")
+    void testSingleElement() {
+        int[][] matrix = {{100}};
+        PrefixSum2D ps = new PrefixSum2D(matrix);
+
+        assertEquals(100L, ps.sumRegion(0, 0, 0, 0));
+    }
+
+    @Test
+    @DisplayName("Test large numbers for overflow (Integer -> Long)")
+    void testLargeNumbers() {
+        // 2 billion. Two of these sum to > MAX_INT
+        int val = 2_000_000_000;
+        int[][] matrix = {{val, val}, {val, val}};
+        PrefixSum2D ps = new PrefixSum2D(matrix);
+
+        // 4 * 2B = 8 Billion
+        assertEquals(8_000_000_000L, ps.sumRegion(0, 0, 1, 1));
+    }
+
+    @Test
+    @DisplayName("Test invalid inputs")
+    void testInvalidInputs() {
+        assertThrows(IllegalArgumentException.class, () -> new PrefixSum2D(null));
+        assertThrows(IllegalArgumentException.class, () -> new PrefixSum2D(new int[][] {})); // empty
+        assertThrows(IllegalArgumentException.class, () -> new PrefixSum2D(new int[][] {{}})); // empty row
+    }
+
+    @Test
+    @DisplayName("Test invalid query ranges")
+    void testInvalidRanges() {
+        int[][] matrix = {{1, 2}, {3, 4}};
+        PrefixSum2D ps = new PrefixSum2D(matrix);
+
+        // Negative indices
+        assertThrows(IndexOutOfBoundsException.class, () -> ps.sumRegion(-1, 0, 0, 0));
+        assertThrows(IndexOutOfBoundsException.class, () -> ps.sumRegion(0, -1, 0, 0));
+
+        // Out of bounds
+        assertThrows(IndexOutOfBoundsException.class, () -> ps.sumRegion(0, 0, 2, 0)); // row2 too big
+        assertThrows(IndexOutOfBoundsException.class, () -> ps.sumRegion(0, 0, 0, 2)); // col2 too big
+
+        // Inverted ranges (start > end)
+        assertThrows(IndexOutOfBoundsException.class, () -> ps.sumRegion(1, 0, 0, 0)); // row1 > row2
+        assertThrows(IndexOutOfBoundsException.class, () -> ps.sumRegion(0, 1, 0, 0)); // col1 > col2
+    }
+}
diff --git a/src/test/java/com/thealgorithms/prefixsum/PrefixSumTest.java b/src/test/java/com/thealgorithms/prefixsum/PrefixSumTest.java
new file mode 100644
index 000000000000..a421b62e9306
--- /dev/null
+++ b/src/test/java/com/thealgorithms/prefixsum/PrefixSumTest.java
@@ -0,0 +1,80 @@
+package com.thealgorithms.prefixsum;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class PrefixSumTest {
+
+    @Test
+    @DisplayName("Test basic sum with positive integers")
+    void testStandardCase() {
+        int[] input = {1, 2, 3, 4, 5};
+        PrefixSum ps = new PrefixSum(input);
+
+        // Sum of range [0, 4] -> 15
+        assertEquals(15L, ps.sumRange(0, 4));
+
+        // Sum of range [1, 3] -> 9
+        assertEquals(9L, ps.sumRange(1, 3));
+    }
+
+    @Test
+    @DisplayName("Test array with negative numbers and zeros")
+    void testNegativeAndZeros() {
+        int[] input = {-2, 0, 3, -5, 2, -1};
+        PrefixSum ps = new PrefixSum(input);
+
+        assertEquals(1L, ps.sumRange(0, 2));
+        assertEquals(-1L, ps.sumRange(2, 5));
+        assertEquals(0L, ps.sumRange(1, 1));
+    }
+
+    @Test
+    @DisplayName("Test with large integers to verify overflow handling")
+    void testLargeNumbers() {
+        // Two values that fit in int, but their sum exceeds Integer.MAX_VALUE
+        // Integer.MAX_VALUE is approx 2.14 billion.
+        int val = 2_000_000_000;
+        int[] input = {val, val, val};
+        PrefixSum ps = new PrefixSum(input);
+
+        // Sum of three 2 billion values is 6 billion (fits in long, overflows int)
+        assertEquals(6_000_000_000L, ps.sumRange(0, 2));
+    }
+
+    @Test
+    @DisplayName("Test single element array")
+    void testSingleElement() {
+        int[] input = {42};
+        PrefixSum ps = new PrefixSum(input);
+        assertEquals(42L, ps.sumRange(0, 0));
+    }
+
+    @Test
+    @DisplayName("Test constructor with null input")
+    void testNullInput() {
+        assertThrows(IllegalArgumentException.class, () -> new PrefixSum(null));
+    }
+
+    @Test
+    @DisplayName("Test empty array behavior")
+    void testEmptyArray() {
+        int[] input = {};
+        PrefixSum ps = new PrefixSum(input);
+        assertThrows(IndexOutOfBoundsException.class, () -> ps.sumRange(0, 0));
+    }
+
+    @Test
+    @DisplayName("Test invalid range indices")
+    void testInvalidIndices() {
+        int[] input = {10, 20, 30};
+        PrefixSum ps = new PrefixSum(input);
+
+        assertThrows(IndexOutOfBoundsException.class, () -> ps.sumRange(-1, 1));
+        assertThrows(IndexOutOfBoundsException.class, () -> ps.sumRange(0, 3));
+        assertThrows(IndexOutOfBoundsException.class, () -> ps.sumRange(2, 1));
+    }
+}

From 7339b9dfe9f8dc1e516866c6e159bedbf8de2198 Mon Sep 17 00:00:00 2001
From: Gopesh Pandey <gopeshpandey0807@gmail.com>
Date: Tue, 20 Jan 2026 02:06:03 +0530
Subject: [PATCH 1166/1338] Add distance between two points algorithm (#7218)

* Add distance between two points algorithm

* Create DistanceBetweenTwoPointsTest.java

* DistanceBetweenTwoPoints.java

* Fix test file package and project structure

* Delete src/test/java/com/thealgorithms/DistanceBetweenTwoPointsTest.java

* Apply clang-format compliant formatting

* Apply clang-format

---------

Co-authored-by: a <19151554+alxkm@users.noreply.github.com>
---
 .../maths/DistanceBetweenTwoPoints.java       | 33 +++++++++++++++++++
 .../maths/DistanceBetweenTwoPointsTest.java   | 23 +++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/DistanceBetweenTwoPoints.java
 create mode 100644 src/test/java/com/thealgorithms/maths/DistanceBetweenTwoPointsTest.java

diff --git a/src/main/java/com/thealgorithms/maths/DistanceBetweenTwoPoints.java b/src/main/java/com/thealgorithms/maths/DistanceBetweenTwoPoints.java
new file mode 100644
index 000000000000..cd1c9205b328
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/DistanceBetweenTwoPoints.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.maths;
+
+/**
+ * Distance Between Two Points in 2D Space.
+ *
+ * <p>This class provides a method to calculate the Euclidean distance between two points in a
+ * two-dimensional plane.
+ *
+ * <p>Formula: d = sqrt((x2 - x1)^2 + (y2 - y1)^2)
+ *
+ * <p>Reference: https://en.wikipedia.org/wiki/Euclidean_distance
+ */
+public final class DistanceBetweenTwoPoints {
+
+    private DistanceBetweenTwoPoints() {
+        // Utility class; prevent instantiation
+    }
+
+    /**
+     * Calculate the Euclidean distance between two points.
+     *
+     * @param x1 x-coordinate of the first point
+     * @param y1 y-coordinate of the first point
+     * @param x2 x-coordinate of the second point
+     * @param y2 y-coordinate of the second point
+     * @return Euclidean distance between the two points
+     */
+    public static double calculate(final double x1, final double y1, final double x2, final double y2) {
+        final double deltaX = x2 - x1;
+        final double deltaY = y2 - y1;
+        return Math.sqrt(deltaX * deltaX + deltaY * deltaY);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/DistanceBetweenTwoPointsTest.java b/src/test/java/com/thealgorithms/maths/DistanceBetweenTwoPointsTest.java
new file mode 100644
index 000000000000..6bd124629740
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/DistanceBetweenTwoPointsTest.java
@@ -0,0 +1,23 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class DistanceBetweenTwoPointsTest {
+
+    @Test
+    void testDistanceSimple() {
+        assertEquals(5.0, DistanceBetweenTwoPoints.calculate(0, 0, 3, 4), 1e-9);
+    }
+
+    @Test
+    void testDistanceNegativeCoordinates() {
+        assertEquals(5.0, DistanceBetweenTwoPoints.calculate(-1, -1, 2, 3), 1e-9);
+    }
+
+    @Test
+    void testSamePoint() {
+        assertEquals(0.0, DistanceBetweenTwoPoints.calculate(2, 2, 2, 2), 1e-9);
+    }
+}

From ba5ccbe0c74330c34e3b643f23828fbd78505d96 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 20 Jan 2026 12:38:12 +0000
Subject: [PATCH 1167/1338] chore(deps-dev): bump
 com.mebigfatguy.fb-contrib:fb-contrib from 7.7.3 to 7.7.4 (#7222)

* chore(deps-dev): bump com.mebigfatguy.fb-contrib:fb-contrib

Bumps [com.mebigfatguy.fb-contrib:fb-contrib](https://github.com/mebigfatguy/fb-contrib) from 7.7.3 to 7.7.4.
- [Commits](https://github.com/mebigfatguy/fb-contrib/compare/v7.7.3...v7.7.4)

---
updated-dependencies:
- dependency-name: com.mebigfatguy.fb-contrib:fb-contrib
  dependency-version: 7.7.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

* fix: supporess new warnings

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 pom.xml              |  2 +-
 spotbugs-exclude.xml | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index a685e334460c..3f81e66d35c0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -127,7 +127,7 @@
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.7.3</version>
+                            <version>7.7.4</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 3e2f1ff84ca8..9269e3a87e88 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -207,6 +207,27 @@
     <Match>
         <Bug pattern="FII_USE_ARRAYS_STREAM" />
     </Match>
+    <Match>
+        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_EQUALS" />
+    </Match>
+    <Match>
+        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_NOT_EQUALS" />
+    </Match>
+    <Match>
+        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_ACTUAL_CONSTANT" />
+    </Match>
+    <Match>
+        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_INEXACT_DOUBLE" />
+    </Match>
+    <Match>
+        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_NOT_NULL" />
+    </Match>
+    <Match>
+        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_NULL" />
+    </Match>
+    <Match>
+        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_IMPOSSIBLE_NULL" />
+    </Match>
     <!-- find-sec-bugs -->
     <Match>
         <Bug pattern="PREDICTABLE_RANDOM" />

From 1b014a2ea470ac41363443aaca90eec424411622 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 20 Jan 2026 22:02:10 +0100
Subject: [PATCH 1168/1338] style: include
 `UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_NULL` (#7225)

---
 spotbugs-exclude.xml                                   |  3 ---
 .../thealgorithms/ciphers/PermutationCipherTest.java   |  5 +++--
 .../thealgorithms/datastructures/trees/TreapTest.java  |  3 ++-
 .../LongestCommonSubsequenceTest.java                  | 10 ++++------
 4 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 9269e3a87e88..f89bad8bebaf 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -222,9 +222,6 @@
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_NOT_NULL" />
     </Match>
-    <Match>
-        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_NULL" />
-    </Match>
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_IMPOSSIBLE_NULL" />
     </Match>
diff --git a/src/test/java/com/thealgorithms/ciphers/PermutationCipherTest.java b/src/test/java/com/thealgorithms/ciphers/PermutationCipherTest.java
index 4ba6787cc97e..ecb7455c1ba2 100644
--- a/src/test/java/com/thealgorithms/ciphers/PermutationCipherTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/PermutationCipherTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.ciphers;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
@@ -121,8 +122,8 @@ void testNullString() {
         String decrypted = cipher.decrypt(encrypted, key);
 
         // then
-        assertEquals(null, encrypted);
-        assertEquals(null, decrypted);
+        assertNull(encrypted);
+        assertNull(decrypted);
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java b/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java
index 09ada594faca..52b74a7a1faf 100644
--- a/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/trees/TreapTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 import org.junit.jupiter.api.Test;
 
@@ -30,7 +31,7 @@ public void searchAndNotFound() {
         treap.insert(3);
         treap.insert(8);
         treap.insert(1);
-        assertEquals(null, treap.search(4));
+        assertNull(treap.search(4));
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java
index 40bbdff15ca6..91169c4cc9d8 100644
--- a/src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LongestCommonSubsequenceTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.dynamicprogramming;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 import org.junit.jupiter.api.Test;
 
@@ -55,27 +56,24 @@ public void testLCSWithBothEmptyStrings() {
     public void testLCSWithNullFirstString() {
         String str1 = null;
         String str2 = "XYZ";
-        String expected = null; // Should return null if first string is null
         String result = LongestCommonSubsequence.getLCS(str1, str2);
-        assertEquals(expected, result);
+        assertNull(result);
     }
 
     @Test
     public void testLCSWithNullSecondString() {
         String str1 = "ABC";
         String str2 = null;
-        String expected = null; // Should return null if second string is null
         String result = LongestCommonSubsequence.getLCS(str1, str2);
-        assertEquals(expected, result);
+        assertNull(result);
     }
 
     @Test
     public void testLCSWithNullBothStrings() {
         String str1 = null;
         String str2 = null;
-        String expected = null; // Should return null if both strings are null
         String result = LongestCommonSubsequence.getLCS(str1, str2);
-        assertEquals(expected, result);
+        assertNull(result);
     }
 
     @Test

From 0e8291e66900b48e4be236121a63147e3dcf6b5f Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 21 Jan 2026 10:55:09 +0100
Subject: [PATCH 1169/1338] style: include
 `UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_NOT_NULL` (#7226)

---
 spotbugs-exclude.xml                                          | 3 ---
 .../thealgorithms/datastructures/heaps/HeapElementTest.java   | 3 ++-
 .../maths/LinearDiophantineEquationsSolverTest.java           | 4 ++--
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index f89bad8bebaf..410c1f8c5566 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -219,9 +219,6 @@
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_INEXACT_DOUBLE" />
     </Match>
-    <Match>
-        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_NOT_NULL" />
-    </Match>
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_IMPOSSIBLE_NULL" />
     </Match>
diff --git a/src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java b/src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java
index d04a9de8a94b..792969200c82 100644
--- a/src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/heaps/HeapElementTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 
 import org.junit.jupiter.api.Test;
@@ -39,7 +40,7 @@ void testEquals() {
 
         assertEquals(element1, element2); // Same key and info
         assertNotEquals(element1, element3); // Different key
-        assertNotEquals(null, element1); // Check for null
+        assertNotNull(element1);
         assertNotEquals("String", element1); // Check for different type
     }
 
diff --git a/src/test/java/com/thealgorithms/maths/LinearDiophantineEquationsSolverTest.java b/src/test/java/com/thealgorithms/maths/LinearDiophantineEquationsSolverTest.java
index c4205985dbfd..885382e29ca2 100644
--- a/src/test/java/com/thealgorithms/maths/LinearDiophantineEquationsSolverTest.java
+++ b/src/test/java/com/thealgorithms/maths/LinearDiophantineEquationsSolverTest.java
@@ -176,7 +176,7 @@ void testSolutionEquality() {
         assertEquals(solution1, solution2);
         assertNotEquals(solution3, solution1);
         assertEquals(solution1, solution1);
-        assertNotEquals(null, solution1);
+        assertNotNull(solution1);
         assertNotEquals("string", solution1);
     }
 
@@ -217,7 +217,7 @@ void testGcdSolutionWrapperEquality() {
         assertEquals(wrapper1, wrapper2);
         assertNotEquals(wrapper3, wrapper1);
         assertEquals(wrapper1, wrapper1);
-        assertNotEquals(null, wrapper1);
+        assertNotNull(wrapper1);
         assertNotEquals("string", wrapper1);
     }
 

From 0f9139dc42bd9beb86837bd854e7b13d46a961c8 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 22 Jan 2026 09:24:45 +0100
Subject: [PATCH 1170/1338] style: include
 `UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_NOT_EQUALS` (#7229)

---
 spotbugs-exclude.xml                          |  3 ---
 .../com/thealgorithms/maths/VolumeTest.java   | 20 +++++++++----------
 2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 410c1f8c5566..c8a7f71cd880 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -210,9 +210,6 @@
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_EQUALS" />
     </Match>
-    <Match>
-        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_NOT_EQUALS" />
-    </Match>
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_ACTUAL_CONSTANT" />
     </Match>
diff --git a/src/test/java/com/thealgorithms/maths/VolumeTest.java b/src/test/java/com/thealgorithms/maths/VolumeTest.java
index 7cd0c6716147..1ba0aec47cef 100644
--- a/src/test/java/com/thealgorithms/maths/VolumeTest.java
+++ b/src/test/java/com/thealgorithms/maths/VolumeTest.java
@@ -1,6 +1,6 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
@@ -10,30 +10,30 @@ public class VolumeTest {
     public void volume() {
 
         /* test cube */
-        assertTrue(Volume.volumeCube(7) == 343.0);
+        assertEquals(Volume.volumeCube(7), 343.0);
 
         /* test cuboid */
-        assertTrue(Volume.volumeCuboid(2, 5, 7) == 70.0);
+        assertEquals(Volume.volumeCuboid(2, 5, 7), 70.0);
 
         /* test sphere */
-        assertTrue(Volume.volumeSphere(7) == 1436.7550402417319);
+        assertEquals(Volume.volumeSphere(7), 1436.7550402417319);
 
         /* test cylinder */
-        assertTrue(Volume.volumeCylinder(3, 7) == 197.92033717615698);
+        assertEquals(Volume.volumeCylinder(3, 7), 197.92033717615698);
 
         /* test hemisphere */
-        assertTrue(Volume.volumeHemisphere(7) == 718.3775201208659);
+        assertEquals(Volume.volumeHemisphere(7), 718.3775201208659);
 
         /* test cone */
-        assertTrue(Volume.volumeCone(3, 7) == 65.97344572538566);
+        assertEquals(Volume.volumeCone(3, 7), 65.97344572538566);
 
         /* test prism */
-        assertTrue(Volume.volumePrism(10, 2) == 20.0);
+        assertEquals(Volume.volumePrism(10, 2), 20.0);
 
         /* test pyramid */
-        assertTrue(Volume.volumePyramid(10, 3) == 10.0);
+        assertEquals(Volume.volumePyramid(10, 3), 10.0);
 
         /* test frustum */
-        assertTrue(Volume.volumeFrustumOfCone(3, 5, 7) == 359.188760060433);
+        assertEquals(Volume.volumeFrustumOfCone(3, 5, 7), 359.188760060433);
     }
 }

From a7eeee2b5b20153e47a015ff6e8e8cb66d1424a8 Mon Sep 17 00:00:00 2001
From: Mohammed Vijahath <116938255+vizahat36@users.noreply.github.com>
Date: Thu, 22 Jan 2026 21:39:23 +0530
Subject: [PATCH 1171/1338] Fix: NumberFormatException with non-ASCII Unicode
 digits in MyAtoi (#7231)

Fix myAtoi handling of non-ASCII Unicode digits
---
 src/main/java/com/thealgorithms/strings/MyAtoi.java | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/strings/MyAtoi.java b/src/main/java/com/thealgorithms/strings/MyAtoi.java
index 5a7c2ce53b1c..92de4039a582 100644
--- a/src/main/java/com/thealgorithms/strings/MyAtoi.java
+++ b/src/main/java/com/thealgorithms/strings/MyAtoi.java
@@ -45,7 +45,9 @@ public static int myAtoi(String s) {
         int number = 0;
         while (index < length) {
             char ch = s.charAt(index);
-            if (!Character.isDigit(ch)) {
+
+            // Accept only ASCII digits
+            if (ch < '0' || ch > '9') {
                 break;
             }
 

From 1a7f8fe79e81163cf4f9f6d82270edd6e39d1d82 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 23 Jan 2026 09:39:22 +0100
Subject: [PATCH 1172/1338] style: include
 `UTAO_JUNIT_ASSERTION_ODDITIES_IMPOSSIBLE_NULL` (#7238)

---
 spotbugs-exclude.xml                                      | 3 ---
 src/test/java/com/thealgorithms/compression/LZ78Test.java | 2 --
 2 files changed, 5 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index c8a7f71cd880..8c51fcf42b2e 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -216,9 +216,6 @@
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_INEXACT_DOUBLE" />
     </Match>
-    <Match>
-        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_IMPOSSIBLE_NULL" />
-    </Match>
     <!-- find-sec-bugs -->
     <Match>
         <Bug pattern="PREDICTABLE_RANDOM" />
diff --git a/src/test/java/com/thealgorithms/compression/LZ78Test.java b/src/test/java/com/thealgorithms/compression/LZ78Test.java
index 7889b50b76f3..da1fd8d23318 100644
--- a/src/test/java/com/thealgorithms/compression/LZ78Test.java
+++ b/src/test/java/com/thealgorithms/compression/LZ78Test.java
@@ -1,7 +1,6 @@
 package com.thealgorithms.compression;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
@@ -286,7 +285,6 @@ void testTokenStructure() {
         // All tokens should have valid indices (>= 0)
         for (LZ78.Token token : compressed) {
             assertTrue(token.index() >= 0);
-            assertNotNull(token.nextChar());
         }
 
         String decompressed = LZ78.decompress(compressed);

From 0b0cefe9f9745ec94ffee3575b98aa953a8c8588 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 24 Jan 2026 14:16:48 +0100
Subject: [PATCH 1173/1338] style: include
 `UTAO_JUNIT_ASSERTION_ODDITIES_ACTUAL_CONSTANT` (#7239)

---
 spotbugs-exclude.xml                          |  3 --
 .../backtracking/PermutationTest.java         |  4 +-
 .../com/thealgorithms/ciphers/ECCTest.java    |  2 +-
 .../hashmap/hashing/MapTest.java              |  6 +--
 .../queues/PriorityQueuesTest.java            | 28 ++++++-------
 .../thealgorithms/io/BufferedReaderTest.java  | 40 +++++++++----------
 .../maths/DistanceFormulaTest.java            | 26 ++++++------
 .../thealgorithms/maths/FactorialTest.java    |  2 +-
 .../maths/NthUglyNumberTest.java              |  8 ++--
 .../maths/PalindromeNumberTest.java           |  2 +-
 .../thealgorithms/maths/ParseIntegerTest.java |  4 +-
 .../maths/QuadraticEquationSolverTest.java    | 20 +++++-----
 .../thealgorithms/maths/SecondMinMaxTest.java |  6 +--
 .../maths/StandardDeviationTest.java          |  8 ++--
 .../maths/StandardScoreTest.java              |  8 ++--
 .../com/thealgorithms/maths/VolumeTest.java   | 18 ++++-----
 .../misc/MedianOfRunningArrayTest.java        |  2 +-
 .../searches/BinarySearch2dArrayTest.java     |  6 +--
 .../thealgorithms/searches/KMPSearchTest.java | 10 ++---
 .../searches/QuickSelectTest.java             |  2 +-
 .../sorts/TopologicalSortTest.java            |  2 +-
 .../thealgorithms/strings/WordLadderTest.java |  6 +--
 .../zigZagPattern/ZigZagPatternTest.java      |  4 +-
 23 files changed, 107 insertions(+), 110 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 8c51fcf42b2e..1390387bacdf 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -210,9 +210,6 @@
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_EQUALS" />
     </Match>
-    <Match>
-        <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_ACTUAL_CONSTANT" />
-    </Match>
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_INEXACT_DOUBLE" />
     </Match>
diff --git a/src/test/java/com/thealgorithms/backtracking/PermutationTest.java b/src/test/java/com/thealgorithms/backtracking/PermutationTest.java
index 76a714829109..54747e5e73a1 100644
--- a/src/test/java/com/thealgorithms/backtracking/PermutationTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/PermutationTest.java
@@ -12,13 +12,13 @@ public class PermutationTest {
     @Test
     void testNoElement() {
         List<Integer[]> result = Permutation.permutation(new Integer[] {});
-        assertEquals(result.get(0).length, 0);
+        assertEquals(0, result.get(0).length);
     }
 
     @Test
     void testSingleElement() {
         List<Integer[]> result = Permutation.permutation(new Integer[] {1});
-        assertEquals(result.get(0)[0], 1);
+        assertEquals(1, result.get(0)[0]);
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/ciphers/ECCTest.java b/src/test/java/com/thealgorithms/ciphers/ECCTest.java
index 701f801af1c8..b78ba51f7c3e 100644
--- a/src/test/java/com/thealgorithms/ciphers/ECCTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/ECCTest.java
@@ -37,7 +37,7 @@ void testEncrypt() {
         System.out.println("Base Point G: " + curve.getBasePoint());
 
         // Verify that the ciphertext is not empty
-        assertEquals(cipherText.length, 2); // Check if the ciphertext contains two points (R and S)
+        assertEquals(2, cipherText.length); // Check if the ciphertext contains two points (R and S)
 
         // Output the encrypted coordinate points
         System.out.println("Encrypted Points:");
diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java
index 44551a8adac6..ef7739a2e8a9 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/MapTest.java
@@ -81,19 +81,19 @@ void containsTest() {
     @Test
     void sizeTest() {
         Map<Integer, String> map = getMap();
-        assertEquals(map.size(), 0);
+        assertEquals(0, map.size());
 
         for (int i = -100; i < 100; i++) {
             map.put(i, String.valueOf(i));
         }
 
-        assertEquals(map.size(), 200);
+        assertEquals(200, map.size());
 
         for (int i = -50; i < 50; i++) {
             map.delete(i);
         }
 
-        assertEquals(map.size(), 100);
+        assertEquals(100, map.size());
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java b/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java
index e97fe091c556..3bb8bbabb761 100644
--- a/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/queues/PriorityQueuesTest.java
@@ -9,14 +9,14 @@ class PriorityQueuesTest {
     void testPQInsertion() {
         PriorityQueue myQueue = new PriorityQueue(4);
         myQueue.insert(2);
-        Assertions.assertEquals(myQueue.peek(), 2);
+        Assertions.assertEquals(2, myQueue.peek());
 
         myQueue.insert(5);
         myQueue.insert(3);
-        Assertions.assertEquals(myQueue.peek(), 5);
+        Assertions.assertEquals(5, myQueue.peek());
 
         myQueue.insert(10);
-        Assertions.assertEquals(myQueue.peek(), 10);
+        Assertions.assertEquals(10, myQueue.peek());
     }
 
     @Test
@@ -28,32 +28,32 @@ void testPQDeletion() {
         myQueue.insert(10);
 
         myQueue.remove();
-        Assertions.assertEquals(myQueue.peek(), 5);
+        Assertions.assertEquals(5, myQueue.peek());
         myQueue.remove();
         myQueue.remove();
-        Assertions.assertEquals(myQueue.peek(), 2);
+        Assertions.assertEquals(2, myQueue.peek());
     }
 
     @Test
     void testPQExtra() {
         PriorityQueue myQueue = new PriorityQueue(4);
-        Assertions.assertEquals(myQueue.isEmpty(), true);
-        Assertions.assertEquals(myQueue.isFull(), false);
+        Assertions.assertTrue(myQueue.isEmpty());
+        Assertions.assertFalse(myQueue.isFull());
         myQueue.insert(2);
         myQueue.insert(5);
-        Assertions.assertEquals(myQueue.isFull(), false);
+        Assertions.assertFalse(myQueue.isFull());
         myQueue.insert(3);
         myQueue.insert(10);
-        Assertions.assertEquals(myQueue.isEmpty(), false);
-        Assertions.assertEquals(myQueue.isFull(), true);
+        Assertions.assertFalse(myQueue.isEmpty());
+        Assertions.assertTrue(myQueue.isFull());
 
         myQueue.remove();
-        Assertions.assertEquals(myQueue.getSize(), 3);
-        Assertions.assertEquals(myQueue.peek(), 5);
+        Assertions.assertEquals(3, myQueue.getSize());
+        Assertions.assertEquals(5, myQueue.peek());
         myQueue.remove();
         myQueue.remove();
-        Assertions.assertEquals(myQueue.peek(), 2);
-        Assertions.assertEquals(myQueue.getSize(), 1);
+        Assertions.assertEquals(2, myQueue.peek());
+        Assertions.assertEquals(1, myQueue.getSize());
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/io/BufferedReaderTest.java b/src/test/java/com/thealgorithms/io/BufferedReaderTest.java
index 891c3066058e..088e86f8f7c5 100644
--- a/src/test/java/com/thealgorithms/io/BufferedReaderTest.java
+++ b/src/test/java/com/thealgorithms/io/BufferedReaderTest.java
@@ -17,15 +17,15 @@ public void testPeeks() throws IOException {
         BufferedReader reader = new BufferedReader(input);
 
         // read the first letter
-        assertEquals(reader.read(), 'H');
+        assertEquals('H', reader.read());
         len--;
-        assertEquals(reader.available(), len);
+        assertEquals(len, reader.available());
 
         // position: H[e]llo!\nWorld!
         // reader.read() will be == 'e'
-        assertEquals(reader.peek(1), 'l');
-        assertEquals(reader.peek(2), 'l'); // second l
-        assertEquals(reader.peek(3), 'o');
+        assertEquals('l', reader.peek(1));
+        assertEquals('l', reader.peek(2)); // second l
+        assertEquals('o', reader.peek(3));
     }
 
     @Test
@@ -38,21 +38,21 @@ public void testMixes() throws IOException {
         BufferedReader reader = new BufferedReader(input);
 
         // read the first letter
-        assertEquals(reader.read(), 'H'); // first letter
+        assertEquals('H', reader.read()); // first letter
         len--;
 
-        assertEquals(reader.peek(1), 'l'); // third later (second letter after 'H')
-        assertEquals(reader.read(), 'e'); // second letter
+        assertEquals('l', reader.peek(1)); // third later (second letter after 'H')
+        assertEquals('e', reader.read()); // second letter
         len--;
-        assertEquals(reader.available(), len);
+        assertEquals(len, reader.available());
 
         // position: H[e]llo!\nWorld!
-        assertEquals(reader.peek(2), 'o'); // second l
-        assertEquals(reader.peek(3), '!');
-        assertEquals(reader.peek(4), '\n');
+        assertEquals('o', reader.peek(2)); // second l
+        assertEquals('!', reader.peek(3));
+        assertEquals('\n', reader.peek(4));
 
-        assertEquals(reader.read(), 'l'); // third letter
-        assertEquals(reader.peek(1), 'o'); // fourth letter
+        assertEquals('l', reader.read()); // third letter
+        assertEquals('o', reader.peek(1)); // fourth letter
 
         for (int i = 0; i < 6; i++) {
             reader.read();
@@ -74,23 +74,23 @@ public void testBlockPractical() throws IOException {
         ByteArrayInputStream input = new ByteArrayInputStream(bytes);
         BufferedReader reader = new BufferedReader(input);
 
-        assertEquals(reader.peek(), 'H');
-        assertEquals(reader.read(), '!'); // read the first letter
+        assertEquals('H', reader.peek());
+        assertEquals('!', reader.read()); // read the first letter
         len--;
 
         // this only reads the next 5 bytes (Hello) because
         // the default buffer size = 5
-        assertEquals(new String(reader.readBlock()), "Hello");
+        assertEquals("Hello", new String(reader.readBlock()));
         len -= 5;
         assertEquals(reader.available(), len);
 
         // maybe kind of a practical demonstration / use case
         if (reader.read() == '\n') {
-            assertEquals(reader.read(), 'W');
-            assertEquals(reader.read(), 'o');
+            assertEquals('W', reader.read());
+            assertEquals('o', reader.read());
 
             // the rest of the blocks
-            assertEquals(new String(reader.readBlock()), "rld!");
+            assertEquals("rld!", new String(reader.readBlock()));
         } else {
             // should not reach
             throw new IOException("Something not right");
diff --git a/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java b/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java
index 3a14b80dd4f9..66f3b7b03938 100644
--- a/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java
+++ b/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java
@@ -9,78 +9,78 @@ public class DistanceFormulaTest {
 
     @Test
     void euclideanTest1() {
-        Assertions.assertEquals(DistanceFormula.euclideanDistance(1, 1, 2, 2), 1.4142135623730951);
+        Assertions.assertEquals(1.4142135623730951, DistanceFormula.euclideanDistance(1, 1, 2, 2));
     }
 
     @Test
     void euclideanTest2() {
-        Assertions.assertEquals(DistanceFormula.euclideanDistance(1, 3, 8, 0), 7.0710678118654755);
+        Assertions.assertEquals(7.0710678118654755, DistanceFormula.euclideanDistance(1, 3, 8, 0));
     }
 
     @Test
     void euclideanTest3() {
-        Assertions.assertEquals(DistanceFormula.euclideanDistance(2.4, 9.1, 55.1, 100), 110.91911467371168);
+        Assertions.assertEquals(110.91911467371168, DistanceFormula.euclideanDistance(2.4, 9.1, 55.1, 100));
     }
 
     @Test
     void euclideanTest4() {
-        Assertions.assertEquals(DistanceFormula.euclideanDistance(1000, 13, 20000, 84), 19022.067605809836);
+        Assertions.assertEquals(19022.067605809836, DistanceFormula.euclideanDistance(1000, 13, 20000, 84));
     }
 
     @Test
     public void manhattantest1() {
-        assertEquals(DistanceFormula.manhattanDistance(1, 2, 3, 4), 4);
+        assertEquals(4, DistanceFormula.manhattanDistance(1, 2, 3, 4));
     }
 
     @Test
     public void manhattantest2() {
-        assertEquals(DistanceFormula.manhattanDistance(6.5, 8.4, 20.1, 13.6), 18.8);
+        assertEquals(18.8, DistanceFormula.manhattanDistance(6.5, 8.4, 20.1, 13.6));
     }
 
     @Test
     public void manhattanTest3() {
-        assertEquals(DistanceFormula.manhattanDistance(10.112, 50, 8, 25.67), 26.442);
+        assertEquals(26.442, DistanceFormula.manhattanDistance(10.112, 50, 8, 25.67));
     }
 
     @Test
     public void hammingTest1() {
         int[] array1 = {1, 1, 1, 1};
         int[] array2 = {0, 0, 0, 0};
-        assertEquals(DistanceFormula.hammingDistance(array1, array2), 4);
+        assertEquals(4, DistanceFormula.hammingDistance(array1, array2));
     }
 
     @Test
     public void hammingTest2() {
         int[] array1 = {1, 1, 1, 1};
         int[] array2 = {1, 1, 1, 1};
-        assertEquals(DistanceFormula.hammingDistance(array1, array2), 0);
+        assertEquals(0, DistanceFormula.hammingDistance(array1, array2));
     }
 
     @Test
     public void hammingTest3() {
         int[] array1 = {1, 0, 0, 1, 1, 0, 1, 1, 0};
         int[] array2 = {0, 1, 0, 0, 1, 1, 1, 0, 0};
-        assertEquals(DistanceFormula.hammingDistance(array1, array2), 5);
+        assertEquals(5, DistanceFormula.hammingDistance(array1, array2));
     }
 
     @Test
     public void minkowskiTest1() {
         double[] array1 = {1, 3, 8, 5};
         double[] array2 = {4, 2, 6, 9};
-        assertEquals(DistanceFormula.minkowskiDistance(array1, array2, 1), 10);
+        assertEquals(10, DistanceFormula.minkowskiDistance(array1, array2, 1));
     }
 
     @Test
     public void minkowskiTest2() {
         double[] array1 = {1, 3, 8, 5};
         double[] array2 = {4, 2, 6, 9};
-        assertEquals(DistanceFormula.minkowskiDistance(array1, array2, 2), 5.477225575051661);
+        assertEquals(5.477225575051661, DistanceFormula.minkowskiDistance(array1, array2, 2));
     }
 
     @Test
     public void minkowskiTest3() {
         double[] array1 = {1, 3, 8, 5};
         double[] array2 = {4, 2, 6, 9};
-        assertEquals(DistanceFormula.minkowskiDistance(array1, array2, 3), 4.641588833612778);
+        assertEquals(4.641588833612778, DistanceFormula.minkowskiDistance(array1, array2, 3));
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/FactorialTest.java b/src/test/java/com/thealgorithms/maths/FactorialTest.java
index b38dc45589ee..3ff7097b8113 100644
--- a/src/test/java/com/thealgorithms/maths/FactorialTest.java
+++ b/src/test/java/com/thealgorithms/maths/FactorialTest.java
@@ -11,7 +11,7 @@ public class FactorialTest {
     @Test
     public void testWhenInvalidInoutProvidedShouldThrowException() {
         IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> Factorial.factorial(-1));
-        assertEquals(exception.getMessage(), EXCEPTION_MESSAGE);
+        assertEquals(EXCEPTION_MESSAGE, exception.getMessage());
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java b/src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java
index 3fe58dadf8a5..1ee437b190c5 100644
--- a/src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java
@@ -48,22 +48,22 @@ public void testGetWithSameObject() {
 
         var uglyNumbers = new NthUglyNumber(new int[] {7, 2, 5, 3});
         for (final var tc : testCases.entrySet()) {
-            assertEquals(uglyNumbers.get(tc.getKey()), tc.getValue());
+            assertEquals(tc.getValue(), uglyNumbers.get(tc.getKey()));
         }
 
-        assertEquals(uglyNumbers.get(999), 385875);
+        assertEquals(385875, uglyNumbers.get(999));
     }
 
     @Test
     public void testGetWithBase1() {
         var uglyNumbers = new NthUglyNumber(new int[] {1});
-        assertEquals(uglyNumbers.get(10), 1);
+        assertEquals(1, uglyNumbers.get(10));
     }
 
     @Test
     public void testGetWithBase2() {
         var uglyNumbers = new NthUglyNumber(new int[] {2});
-        assertEquals(uglyNumbers.get(5), 32);
+        assertEquals(32, uglyNumbers.get(5));
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java b/src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java
index a70100c0b913..4e4bd85d07b5 100644
--- a/src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java
+++ b/src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java
@@ -25,6 +25,6 @@ public void testNumbersAreNotPalindromes() {
     @Test
     public void testIfNegativeInputThenExceptionExpected() {
         IllegalArgumentException exception = Assertions.assertThrows(IllegalArgumentException.class, () -> PalindromeNumber.isPalindrome(-1));
-        Assertions.assertEquals(exception.getMessage(), "Input parameter must not be negative!");
+        Assertions.assertEquals("Input parameter must not be negative!", exception.getMessage());
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/ParseIntegerTest.java b/src/test/java/com/thealgorithms/maths/ParseIntegerTest.java
index 7649e21eb231..a9b78be88042 100644
--- a/src/test/java/com/thealgorithms/maths/ParseIntegerTest.java
+++ b/src/test/java/com/thealgorithms/maths/ParseIntegerTest.java
@@ -14,13 +14,13 @@ public class ParseIntegerTest {
     @Test
     public void testNullInput() {
         IllegalArgumentException exception = Assertions.assertThrows(IllegalArgumentException.class, () -> ParseInteger.parseInt(null));
-        Assertions.assertEquals(exception.getMessage(), NULL_PARAMETER_MESSAGE);
+        Assertions.assertEquals(NULL_PARAMETER_MESSAGE, exception.getMessage());
     }
 
     @Test
     public void testEmptyInput() {
         IllegalArgumentException exception = Assertions.assertThrows(IllegalArgumentException.class, () -> ParseInteger.parseInt(""));
-        Assertions.assertEquals(exception.getMessage(), EMPTY_PARAMETER_MESSAGE);
+        Assertions.assertEquals(EMPTY_PARAMETER_MESSAGE, exception.getMessage());
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java b/src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java
index a2046511ddf5..a6552d56783c 100644
--- a/src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java
+++ b/src/test/java/com/thealgorithms/maths/QuadraticEquationSolverTest.java
@@ -14,10 +14,10 @@ public void testSolveEquationRealRoots() {
         double c = 1.9;
 
         ComplexNumber[] roots = quadraticEquationSolver.solveEquation(a, b, c);
-        Assertions.assertEquals(roots.length, 2);
-        Assertions.assertEquals(roots[0].real, -0.27810465435684306);
+        Assertions.assertEquals(2, roots.length, 2);
+        Assertions.assertEquals(-0.27810465435684306, roots[0].real);
         Assertions.assertNull(roots[0].imaginary);
-        Assertions.assertEquals(roots[1].real, -1.6266572504050616);
+        Assertions.assertEquals(-1.6266572504050616, roots[1].real);
         Assertions.assertNull(roots[1].imaginary);
     }
 
@@ -29,8 +29,8 @@ public void testSolveEquationEqualRoots() {
         double c = 1;
 
         ComplexNumber[] roots = quadraticEquationSolver.solveEquation(a, b, c);
-        Assertions.assertEquals(roots.length, 1);
-        Assertions.assertEquals(roots[0].real, -1);
+        Assertions.assertEquals(1, roots.length);
+        Assertions.assertEquals(-1, roots[0].real);
     }
 
     @Test
@@ -41,10 +41,10 @@ public void testSolveEquationComplexRoots() {
         double c = 5.6;
 
         ComplexNumber[] roots = quadraticEquationSolver.solveEquation(a, b, c);
-        Assertions.assertEquals(roots.length, 2);
-        Assertions.assertEquals(roots[0].real, -0.8695652173913044);
-        Assertions.assertEquals(roots[0].imaginary, 1.2956229935435948);
-        Assertions.assertEquals(roots[1].real, -0.8695652173913044);
-        Assertions.assertEquals(roots[1].imaginary, -1.2956229935435948);
+        Assertions.assertEquals(2, roots.length);
+        Assertions.assertEquals(-0.8695652173913044, roots[0].real);
+        Assertions.assertEquals(1.2956229935435948, roots[0].imaginary);
+        Assertions.assertEquals(-0.8695652173913044, roots[1].real);
+        Assertions.assertEquals(-1.2956229935435948, roots[1].imaginary);
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java b/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java
index c744614e5cfa..c5d47f2213a9 100644
--- a/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java
+++ b/src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java
@@ -29,19 +29,19 @@ public TestCase(final int[] inInputArray, final int inSecondMin, final int inSec
     @Test
     public void testForEmptyInputArray() {
         IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> SecondMinMax.findSecondMin(new int[] {}));
-        assertEquals(exception.getMessage(), EXP_MSG_ARR_LEN_LESS_2);
+        assertEquals(EXP_MSG_ARR_LEN_LESS_2, exception.getMessage());
     }
 
     @Test
     public void testForArrayWithSingleElement() {
         IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> SecondMinMax.findSecondMax(new int[] {1}));
-        assertEquals(exception.getMessage(), EXP_MSG_ARR_LEN_LESS_2);
+        assertEquals(EXP_MSG_ARR_LEN_LESS_2, exception.getMessage());
     }
 
     @Test
     public void testForArrayWithSameElements() {
         IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> SecondMinMax.findSecondMin(new int[] {1, 1, 1, 1}));
-        assertEquals(exception.getMessage(), EXP_MSG_ARR_SAME_ELE);
+        assertEquals(EXP_MSG_ARR_SAME_ELE, exception.getMessage());
     }
 
     @ParameterizedTest
diff --git a/src/test/java/com/thealgorithms/maths/StandardDeviationTest.java b/src/test/java/com/thealgorithms/maths/StandardDeviationTest.java
index 2c10d2d14f3e..4716d389a4ca 100644
--- a/src/test/java/com/thealgorithms/maths/StandardDeviationTest.java
+++ b/src/test/java/com/thealgorithms/maths/StandardDeviationTest.java
@@ -8,19 +8,19 @@ public class StandardDeviationTest {
     @Test
     void test1() {
         double[] t1 = new double[] {1, 1, 1, 1, 1};
-        Assertions.assertEquals(StandardDeviation.stdDev(t1), 0.0);
+        Assertions.assertEquals(0.0, StandardDeviation.stdDev(t1));
     }
 
     @Test
     void test2() {
         double[] t2 = new double[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
-        Assertions.assertEquals(StandardDeviation.stdDev(t2), 2.8722813232690143);
+        Assertions.assertEquals(2.8722813232690143, StandardDeviation.stdDev(t2));
     }
 
     @Test
     void test3() {
         double[] t3 = new double[] {1.1, 8.5, 20.3, 2.4, 6.2};
-        Assertions.assertEquals(StandardDeviation.stdDev(t3), 6.8308125431752265);
+        Assertions.assertEquals(6.8308125431752265, StandardDeviation.stdDev(t3));
     }
 
     @Test
@@ -32,6 +32,6 @@ void test4() {
             100.00045,
             56.7,
         };
-        Assertions.assertEquals(StandardDeviation.stdDev(t4), 38.506117353865775);
+        Assertions.assertEquals(38.506117353865775, StandardDeviation.stdDev(t4));
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/StandardScoreTest.java b/src/test/java/com/thealgorithms/maths/StandardScoreTest.java
index 436b1fd011c6..6858b87ad2c6 100644
--- a/src/test/java/com/thealgorithms/maths/StandardScoreTest.java
+++ b/src/test/java/com/thealgorithms/maths/StandardScoreTest.java
@@ -7,21 +7,21 @@ public class StandardScoreTest {
 
     @Test
     void test1() {
-        Assertions.assertEquals(StandardScore.zScore(2, 0, 5), 0.4);
+        Assertions.assertEquals(0.4, StandardScore.zScore(2, 0, 5));
     }
 
     @Test
     void test2() {
-        Assertions.assertEquals(StandardScore.zScore(1, 1, 1), 0.0);
+        Assertions.assertEquals(0.0, StandardScore.zScore(1, 1, 1));
     }
 
     @Test
     void test3() {
-        Assertions.assertEquals(StandardScore.zScore(2.5, 1.8, 0.7), 1.0);
+        Assertions.assertEquals(1.0, StandardScore.zScore(2.5, 1.8, 0.7));
     }
 
     @Test
     void test4() {
-        Assertions.assertEquals(StandardScore.zScore(8.9, 3, 4.2), 1.4047619047619049);
+        Assertions.assertEquals(1.4047619047619049, StandardScore.zScore(8.9, 3, 4.2));
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/VolumeTest.java b/src/test/java/com/thealgorithms/maths/VolumeTest.java
index 1ba0aec47cef..af882eef7563 100644
--- a/src/test/java/com/thealgorithms/maths/VolumeTest.java
+++ b/src/test/java/com/thealgorithms/maths/VolumeTest.java
@@ -10,30 +10,30 @@ public class VolumeTest {
     public void volume() {
 
         /* test cube */
-        assertEquals(Volume.volumeCube(7), 343.0);
+        assertEquals(343.0, Volume.volumeCube(7));
 
         /* test cuboid */
-        assertEquals(Volume.volumeCuboid(2, 5, 7), 70.0);
+        assertEquals(70.0, Volume.volumeCuboid(2, 5, 7));
 
         /* test sphere */
-        assertEquals(Volume.volumeSphere(7), 1436.7550402417319);
+        assertEquals(1436.7550402417319, Volume.volumeSphere(7));
 
         /* test cylinder */
-        assertEquals(Volume.volumeCylinder(3, 7), 197.92033717615698);
+        assertEquals(197.92033717615698, Volume.volumeCylinder(3, 7));
 
         /* test hemisphere */
-        assertEquals(Volume.volumeHemisphere(7), 718.3775201208659);
+        assertEquals(718.3775201208659, Volume.volumeHemisphere(7));
 
         /* test cone */
-        assertEquals(Volume.volumeCone(3, 7), 65.97344572538566);
+        assertEquals(65.97344572538566, Volume.volumeCone(3, 7));
 
         /* test prism */
-        assertEquals(Volume.volumePrism(10, 2), 20.0);
+        assertEquals(20.0, Volume.volumePrism(10, 2));
 
         /* test pyramid */
-        assertEquals(Volume.volumePyramid(10, 3), 10.0);
+        assertEquals(10.0, Volume.volumePyramid(10, 3));
 
         /* test frustum */
-        assertEquals(Volume.volumeFrustumOfCone(3, 5, 7), 359.188760060433);
+        assertEquals(359.188760060433, Volume.volumeFrustumOfCone(3, 5, 7));
     }
 }
diff --git a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
index f41953035846..c4a74af0ba8b 100644
--- a/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
+++ b/src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
@@ -17,7 +17,7 @@ public class MedianOfRunningArrayTest {
     public void testWhenInvalidInoutProvidedShouldThrowException() {
         var stream = new MedianOfRunningArrayInteger();
         IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, stream::getMedian);
-        assertEquals(exception.getMessage(), EXCEPTION_MESSAGE);
+        assertEquals(EXCEPTION_MESSAGE, exception.getMessage());
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java b/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java
index 18f0afc6a0a6..dec2c86de9c7 100644
--- a/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java
+++ b/src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java
@@ -117,7 +117,7 @@ public void binarySearch2dArrayTestTargetInMiddle() {
         int target = 8;
         // Assert that the requirement, that the target is in the middle row and middle column, is
         // fulfilled.
-        assertEquals(arr[arr.length / 2][arr[0].length / 2], target);
+        assertEquals(target, arr[arr.length / 2][arr[0].length / 2]);
         int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(1, ans[0]);
@@ -135,8 +135,8 @@ public void binarySearch2dArrayTestTargetAboveMiddleRowInMiddleColumn() {
 
         // Assert that the requirement, that he target is in the middle column,
         // in an array with an even number of columns, and on the row "above" the middle row.
-        assertEquals(arr[0].length % 2, 0);
-        assertEquals(arr[arr.length / 2 - 1][arr[0].length / 2], target);
+        assertEquals(0, arr[0].length % 2);
+        assertEquals(target, arr[arr.length / 2 - 1][arr[0].length / 2]);
         int[] ans = BinarySearch2dArray.binarySearch(arr, target);
         System.out.println(Arrays.toString(ans));
         assertEquals(0, ans[0]);
diff --git a/src/test/java/com/thealgorithms/searches/KMPSearchTest.java b/src/test/java/com/thealgorithms/searches/KMPSearchTest.java
index cb804ac6a6a3..216c5fcd7d2c 100644
--- a/src/test/java/com/thealgorithms/searches/KMPSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/KMPSearchTest.java
@@ -14,7 +14,7 @@ public void kmpSearchTestLast() {
         KMPSearch kmpSearch = new KMPSearch();
         int value = kmpSearch.kmpSearch(pat, txt);
         System.out.println(value);
-        assertEquals(value, 10);
+        assertEquals(10, value);
     }
 
     @Test
@@ -25,7 +25,7 @@ public void kmpSearchTestFront() {
         KMPSearch kmpSearch = new KMPSearch();
         int value = kmpSearch.kmpSearch(pat, txt);
         System.out.println(value);
-        assertEquals(value, 0);
+        assertEquals(0, value);
     }
 
     @Test
@@ -36,7 +36,7 @@ public void kmpSearchTestMiddle() {
         KMPSearch kmpSearch = new KMPSearch();
         int value = kmpSearch.kmpSearch(pat, txt);
         System.out.println(value);
-        assertEquals(value, 4);
+        assertEquals(4, value);
     }
 
     @Test
@@ -47,7 +47,7 @@ public void kmpSearchTestNotFound() {
         KMPSearch kmpSearch = new KMPSearch();
         int value = kmpSearch.kmpSearch(pat, txt);
         System.out.println(value);
-        assertEquals(value, 4);
+        assertEquals(4, value);
     }
 
     @Test
@@ -58,6 +58,6 @@ public void kmpSearchTest4() {
         KMPSearch kmpSearch = new KMPSearch();
         int value = kmpSearch.kmpSearch(pat, txt);
         System.out.println(value);
-        assertEquals(value, -1);
+        assertEquals(-1, value);
     }
 }
diff --git a/src/test/java/com/thealgorithms/searches/QuickSelectTest.java b/src/test/java/com/thealgorithms/searches/QuickSelectTest.java
index cf160b0ff4b5..4c96be76861a 100644
--- a/src/test/java/com/thealgorithms/searches/QuickSelectTest.java
+++ b/src/test/java/com/thealgorithms/searches/QuickSelectTest.java
@@ -172,7 +172,7 @@ void quickSelect70thPercentileOfManyElements() {
     void quickSelectMedianOfThreeCharacters() {
         List<Character> elements = Arrays.asList('X', 'Z', 'Y');
         char actual = QuickSelect.select(elements, 1);
-        assertEquals(actual, 'Y');
+        assertEquals('Y', actual);
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java b/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
index d5588b2b968e..e19f5b928263 100644
--- a/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/TopologicalSortTest.java
@@ -58,7 +58,7 @@ public void failureTest() {
         Exception exception = assertThrows(RuntimeException.class, () -> TopologicalSort.sort(graph));
         String expected = "This graph contains a cycle. No linear ordering is possible. "
             + "Back edge: 6 -> 2";
-        assertEquals(exception.getMessage(), expected);
+        assertEquals(expected, exception.getMessage());
     }
     @Test
     void testEmptyGraph() {
diff --git a/src/test/java/com/thealgorithms/strings/WordLadderTest.java b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
index 221953411da7..c029940abfb0 100644
--- a/src/test/java/com/thealgorithms/strings/WordLadderTest.java
+++ b/src/test/java/com/thealgorithms/strings/WordLadderTest.java
@@ -24,7 +24,7 @@ public class WordLadderTest {
     public void testWordLadder() {
 
         List<String> wordList1 = Arrays.asList("hot", "dot", "dog", "lot", "log", "cog");
-        assertEquals(WordLadder.ladderLength("hit", "cog", wordList1), 5);
+        assertEquals(5, WordLadder.ladderLength("hit", "cog", wordList1));
     }
 
     /**
@@ -39,7 +39,7 @@ public void testWordLadder() {
     public void testWordLadder2() {
 
         List<String> wordList2 = Arrays.asList("hot", "dot", "dog", "lot", "log");
-        assertEquals(WordLadder.ladderLength("hit", "cog", wordList2), 0);
+        assertEquals(0, WordLadder.ladderLength("hit", "cog", wordList2));
     }
 
     /**
@@ -54,7 +54,7 @@ public void testWordLadder2() {
     public void testWordLadder3() {
 
         List<String> wordList3 = emptyList();
-        assertEquals(WordLadder.ladderLength("hit", "cog", wordList3), 0);
+        assertEquals(0, WordLadder.ladderLength("hit", "cog", wordList3));
     }
 
     @ParameterizedTest
diff --git a/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java b/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java
index 2cbbfe3d2dd8..9bf118c9b844 100644
--- a/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java
+++ b/src/test/java/com/thealgorithms/strings/zigZagPattern/ZigZagPatternTest.java
@@ -9,8 +9,8 @@ public class ZigZagPatternTest {
     public void testZigZagPattern() {
         String input1 = "HelloWorldFromJava";
         String input2 = "javaIsAProgrammingLanguage";
-        Assertions.assertEquals(ZigZagPattern.encode(input1, 4), "HooeWrrmalolFJvlda");
-        Assertions.assertEquals(ZigZagPattern.encode(input2, 4), "jAaLgasPrmgaaevIrgmnnuaoig");
+        Assertions.assertEquals("HooeWrrmalolFJvlda", ZigZagPattern.encode(input1, 4));
+        Assertions.assertEquals("jAaLgasPrmgaaevIrgmnnuaoig", ZigZagPattern.encode(input2, 4));
         // Edge cases
         Assertions.assertEquals("ABC", ZigZagPattern.encode("ABC", 1)); // Single row
         Assertions.assertEquals("A", ZigZagPattern.encode("A", 2)); // numRows > length of string

From 6fdf2db2989b2cea5ecbf27953f24ff6ac461f82 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sun, 25 Jan 2026 12:44:41 +0100
Subject: [PATCH 1174/1338] style: resolve some of the
 `UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_EQUALS` warnings (#7240)

---
 .../com/thealgorithms/backtracking/CombinationTest.java   | 8 ++++----
 .../java/com/thealgorithms/misc/ShuffleArrayTest.java     | 3 ++-
 .../java/com/thealgorithms/others/PasswordGenTest.java    | 2 +-
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/test/java/com/thealgorithms/backtracking/CombinationTest.java b/src/test/java/com/thealgorithms/backtracking/CombinationTest.java
index a9d1163f3ecd..5d2f99ccadf8 100644
--- a/src/test/java/com/thealgorithms/backtracking/CombinationTest.java
+++ b/src/test/java/com/thealgorithms/backtracking/CombinationTest.java
@@ -28,16 +28,16 @@ void testNoElement() {
     @Test
     void testLengthOne() {
         List<TreeSet<Integer>> result = Combination.combination(new Integer[] {1, 2}, 1);
-        assertTrue(result.get(0).iterator().next() == 1);
-        assertTrue(result.get(1).iterator().next() == 2);
+        assertEquals(1, result.get(0).iterator().next());
+        assertEquals(2, result.get(1).iterator().next());
     }
 
     @Test
     void testLengthTwo() {
         List<TreeSet<Integer>> result = Combination.combination(new Integer[] {1, 2}, 2);
         Integer[] arr = result.get(0).toArray(new Integer[2]);
-        assertTrue(arr[0] == 1);
-        assertTrue(arr[1] == 2);
+        assertEquals(1, arr[0]);
+        assertEquals(2, arr[1]);
     }
 
     @Test
diff --git a/src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java b/src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java
index 915b83e376b6..c1adafa18d9f 100644
--- a/src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java
+++ b/src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.misc;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -67,7 +68,7 @@ void testShuffleRetainsElements() {
         ShuffleArray.shuffle(arr);
 
         // Check that the shuffled array contains the same elements
-        assertTrue(arr.length == 5);
+        assertEquals(5, arr.length);
         for (int i = 1; i <= 5; i++) {
             assertTrue(contains(arr, i));
         }
diff --git a/src/test/java/com/thealgorithms/others/PasswordGenTest.java b/src/test/java/com/thealgorithms/others/PasswordGenTest.java
index 76492556e75f..4dcdf6b9cf4f 100644
--- a/src/test/java/com/thealgorithms/others/PasswordGenTest.java
+++ b/src/test/java/com/thealgorithms/others/PasswordGenTest.java
@@ -17,7 +17,7 @@ public void failGenerationWithSameMinMaxLengthTest() {
     @Test
     public void generateOneCharacterPassword() {
         String tempPassword = PasswordGen.generatePassword(1, 2);
-        assertTrue(tempPassword.length() == 1);
+        assertEquals(1, tempPassword.length());
     }
 
     @Test

From a3efc108b8970adfe71baef44510b1f5552ca342 Mon Sep 17 00:00:00 2001
From: Deniz Altunkapan <deniz.altunkapan@outlook.com>
Date: Mon, 26 Jan 2026 22:33:04 +0100
Subject: [PATCH 1175/1338] Docs/remove readme korean readme file (#7242)

* fix: prevent duplicate auth header in GitHub Actions workflow

* chore: remove Korean README file
---
 .github/workflows/update-directorymd.yml |   2 +-
 README-ko.md                             | 191 -----------------------
 2 files changed, 1 insertion(+), 192 deletions(-)
 delete mode 100644 README-ko.md

diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index aa553b46a23b..1cfee6e36e4e 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -1,4 +1,4 @@
-name: Generate Directory Markdown
+name: Generate Directory Markdown
 
 on:
   push:
diff --git a/README-ko.md b/README-ko.md
deleted file mode 100644
index 4f8cab92fc42..000000000000
--- a/README-ko.md
+++ /dev/null
@@ -1,191 +0,0 @@
-# 알고리즘 - 자바
-
-## 이 [개발브런치](https://github.com/TheAlgorithms/Java/tree/Development)는 기존 프로젝트를 Java 프로젝트 구조로 재개발하기 위해 작성되었다. 기여도를 위해 개발 지사로 전환할 수 있다. 자세한 내용은 이 문제를 참조하십시오. 컨트리뷰션을 위해 [개발브런치](https://github.com/TheAlgorithms/Java/tree/Development)로 전환할 수 있다. 자세한 내용은 [이 이슈](https://github.com/TheAlgorithms/Java/issues/474)를 참고하십시오.
-
-### 자바로 구현된 모든 알고리즘들 (교육용)
-
-이것들은 단지 시범을 위한 것이다. 표준 자바 라이브러리에는 성능상의 이유로 더 나은 것들이 구현되어있다
-
-## 정렬 알고리즘
-
-### Bubble(버블 정렬)
-
-![alt text][bubble-image]
-
-From [Wikipedia][bubble-wiki]: 버블 소트(sinking sor라고도 불리움)는 리스트를 반복적인 단계로 접근하여 정렬한다. 각각의 짝을 비교하며, 순서가 잘못된 경우 그접한 아이템들을 스왑하는 알고리즘이다. 더 이상 스왑할 것이 없을 때까지 반복하며, 반복이 끝남음 리스트가 정렬되었음을 의미한다.
-
-**속성**
-
-- 최악의 성능 O(n^2)
-- 최고의 성능 O(n)
-- 평균 성능 O(n^2)
-
-###### View the algorithm in [action][bubble-toptal]
-
-### Insertion(삽입 정렬)
-
-![alt text][insertion-image]
-
-From [Wikipedia][insertion-wiki]: 삽입 정렬은 최종 정렬된 배열(또는 리스트)을 한번에 하나씩 구축하는 알고리즘이다. 이것은 큰 리스트에서 더 나은 알고리즘인 퀵 소트, 힙 소트, 또는 머지 소트보다 훨씬 안좋은 효율을 가진다. 그림에서 각 막대는 정렬해야 하는 배열의 요소를 나타낸다. 상단과 두 번째 상단 막대의 첫 번째 교차점에서 발생하는 것은 두 번째 요소가 첫 번째 요소보다 더 높은 우선 순위를 가지기 때문에 막대로 표시되는 이러한 요소를 교환한 것이다. 이 방법을 반복하면 삽입 정렬이 완료된다.
-
-**속성**
-
-- 최악의 성능 O(n^2)
-- 최고의 성능 O(n)
-- 평균 O(n^2)
-
-###### View the algorithm in [action][insertion-toptal]
-
-### Merge(합병 정렬)
-
-![alt text][merge-image]
-
-From [Wikipedia][merge-wiki]: 컴퓨터 과학에서, 합병 정렬은 효율적인, 범용적인, 비교 기반 정렬 알고리즘이다. 대부분의 구현은 안정적인 분류를 이루는데, 이것은 구현이 정렬된 출력에 동일한 요소의 입력 순서를 유지한다는 것을 의미한다. 합병 정렬은 1945년에 John von Neumann이 발명한 분할 정복 알고리즘이다.
-
-**속성**
-
-- 최악의 성능 O(n log n) (일반적)
-- 최고의 성능 O(n log n)
-- 평균 O(n log n)
-
-###### View the algorithm in [action][merge-toptal]
-
-### Quick(퀵 정렬)
-
-![alt text][quick-image]
-
-From [Wikipedia][quick-wiki]: 퀵 정렬sometimes called partition-exchange sort)은 효율적인 정렬 알고리즘으로, 배열의 요소를 순서대로 정렬하는 체계적인 방법 역활을 한다.
-
-**속성**
-
-- 최악의 성능 O(n^2)
-- 최고의 성능 O(n log n) or O(n) with three-way partition
-- 평균 O(n log n)
-
-###### View the algorithm in [action][quick-toptal]
-
-### Selection(선택 정렬)
-
-![alt text][selection-image]
-
-From [Wikipedia][selection-wiki]: 알고리즘 입력 리스트를 두 부분으로 나눈다 : 첫 부분은 아이템들이 이미 왼쪽에서 오른쪽으로 정렬되었다. 그리고 남은 부분의 아이템들은 나머지 항목을 차지하는 리스트이다. 처음에는 정렬된 리스트는 공백이고 나머지가 전부이다. 오르차순(또는 내림차순) 알고리즘은 가장 작은 요소를 정렬되지 않은 리스트에서 찾고 정렬이 안된 가장 왼쪽(정렬된 리스트) 리스트와 바꾼다. 이렇게 오른쪽으로 나아간다.
-
-**속성**
-
-- 최악의 성능 O(n^2)
-- 최고의 성능 O(n^2)
-- 평균 O(n^2)
-
-###### View the algorithm in [action][selection-toptal]
-
-### Shell(쉘 정렬)
-
-![alt text][shell-image]
-
-From [Wikipedia][shell-wiki]: 쉘 정렬은 멀리 떨어져 있는 항목의 교환을 허용하는 삽입 종류의 일반화이다. 그 아이디어는 모든 n번째 요소가 정렬된 목록을 제공한다는 것을 고려하여 어느 곳에서든지 시작하도록 요소의 목록을 배열하는 것이다. 이러한 목록은 h-sorted로 알려져 있다. 마찬가지로, 각각 개별적으로 정렬된 h 인터리브 목록으로 간주할 수 있다.
-
-**속성**
-
-- 최악의 성능 O(nlog2 2n)
-- 최고의 성능 O(n log n)
-- Average case performance depends on gap sequence
-
-###### View the algorithm in [action][shell-toptal]
-
-### 시간 복잡성 그래프
-
-정렬 알고리즘의 복잡성 비교 (버블 정렬, 삽입 정렬, 선택 정렬)
-
-[복잡성 그래프](https://github.com/prateekiiest/Python/blob/master/sorts/sortinggraphs.png)
-
----
-
-## 검색 알고리즘
-
-### Linear (선형 탐색)
-
-![alt text][linear-image]
-
-From [Wikipedia][linear-wiki]: 선형 탐색 또는 순차 탐색은 목록 내에서 목표값을 찾는 방법이다. 일치 항목이 발견되거나 모든 요소가 탐색될 때까지 목록의 각 요소에 대해 목표값을 순차적으로 검사한다.
-선형 검색은 최악의 선형 시간으로 실행되며 최대 n개의 비교에서 이루어진다. 여기서 n은 목록의 길이다.
-
-**속성**
-
-- 최악의 성능 O(n)
-- 최고의 성능 O(1)
-- 평균 O(n)
-- 최악의 경우 공간 복잡성 O(1) iterative
-
-### Binary (이진 탐색)
-
-![alt text][binary-image]
-
-From [Wikipedia][binary-wiki]: 이진 탐색, (also known as half-interval search or logarithmic search), 은 정렬된 배열 내에서 목표값의 위치를 찾는 검색 알고리즘이다. 목표값을 배열의 중간 요소와 비교한다; 만약 목표값이 동일하지 않으면, 목표물의 절반이 제거되고 검색이 성공할 때까지 나머지 절반에서 속된다.
-
-**속성**
-
-- 최악의 성능 O(log n)
-- 최고의 성능 O(1)
-- 평균 O(log n)
-- 최악의 경우 공간 복잡성 O(1)
-
-[bubble-toptal]: https://www.toptal.com/developers/sorting-algorithms/bubble-sort
-[bubble-wiki]: https://en.wikipedia.org/wiki/Bubble_sort
-[bubble-image]: https://upload.wikimedia.org/wikipedia/commons/thumb/8/83/Bubblesort-edited-color.svg/220px-Bubblesort-edited-color.svg.png "Bubble Sort"
-[insertion-toptal]: https://www.toptal.com/developers/sorting-algorithms/insertion-sort
-[insertion-wiki]: https://en.wikipedia.org/wiki/Insertion_sort
-[insertion-image]: https://upload.wikimedia.org/wikipedia/commons/7/7e/Insertionsort-edited.png "Insertion Sort"
-[quick-toptal]: https://www.toptal.com/developers/sorting-algorithms/quick-sort
-[quick-wiki]: https://en.wikipedia.org/wiki/Quicksort
-[quick-image]: https://upload.wikimedia.org/wikipedia/commons/6/6a/Sorting_quicksort_anim.gif "Quick Sort"
-[merge-toptal]: https://www.toptal.com/developers/sorting-algorithms/merge-sort
-[merge-wiki]: https://en.wikipedia.org/wiki/Merge_sort
-[merge-image]: https://upload.wikimedia.org/wikipedia/commons/c/cc/Merge-sort-example-300px.gif "Merge Sort"
-[selection-toptal]: https://www.toptal.com/developers/sorting-algorithms/selection-sort
-[selection-wiki]: https://en.wikipedia.org/wiki/Selection_sort
-[selection-image]: https://upload.wikimedia.org/wikipedia/commons/thumb/b/b0/Selection_sort_animation.gif/250px-Selection_sort_animation.gif "Selection Sort Sort"
-[shell-toptal]: https://www.toptal.com/developers/sorting-algorithms/shell-sort
-[shell-wiki]: https://en.wikipedia.org/wiki/Shellsort
-[shell-image]: https://upload.wikimedia.org/wikipedia/commons/d/d8/Sorting_shellsort_anim.gif "Shell Sort"
-[linear-wiki]: https://en.wikipedia.org/wiki/Linear_search
-[linear-image]: http://www.tutorialspoint.com/data_structures_algorithms/images/linear_search.gif
-[binary-wiki]: https://en.wikipedia.org/wiki/Binary_search_algorithm
-[binary-image]: https://upload.wikimedia.org/wikipedia/commons/f/f7/Binary_search_into_array.png
-
----
-
-## 나머지 알고리즘에 대한 링크
-
-| 전환                                                            | 다이나믹프로그래밍(DP)                                                                 | 암호                                                                      | 그 외 것들                                             |
-| --------------------------------------------------------------- | -------------------------------------------------------------------------------------- | ------------------------------------------------------------------------- | ------------------------------------------------------ |
-| [Any Base to Any Base](Conversions/AnyBaseToAnyBase.java)       | [Coin Change](DynamicProgramming/CoinChange.java)                                      | [Caesar](Ciphers/Caesar.java)                                             | [Heap Sort](Sorts/HeapSort.java)                       |
-| [Any Base to Decimal](Conversions/AnyBaseToDecimal.java)        | [Egg Dropping](DynamicProgramming/EggDropping.java)                                    | [Columnar Transposition Cipher](Ciphers/ColumnarTranspositionCipher.java) | [Palindromic Prime Checker](Misc/PalindromePrime.java) |
-| [Binary to Decimal](Conversions/BinaryToDecimal.java)           | [Fibonacci](DynamicProgramming/Fibonacci.java)                                         | [RSA](Ciphers/RSA.java)                                                   | More soon...                                           |
-| [Binary to HexaDecimal](Conversions/BinaryToHexadecimal.java)   | [Kadane Algorithm](DynamicProgramming/KadaneAlgorithm.java)                            | more coming soon...                                                       |
-| [Binary to Octal](Conversions/BinaryToOctal.java)               | [Knapsack](DynamicProgramming/Knapsack.java)                                           |
-| [Decimal To Any Base](Conversions/DecimalToAnyBase.java)        | [Longest Common Subsequence](DynamicProgramming/LongestCommonSubsequence.java)         |
-| [Decimal To Binary](Conversions/DecimalToBinary.java)           | [Longest Increasing Subsequence](DynamicProgramming/LongestIncreasingSubsequence.java) |
-| [Decimal To Hexadecimal](Conversions/DecimalToHexaDecimal.java) | [Rod Cutting](DynamicProgramming/RodCutting.java)                                      |
-| and much more...                                                | and more...                                                                            |
-
-### 자료 구조
-
-| 그래프                                                  | 힙                                                             | 리스트                                                        | 큐                                                                          |
-| ------------------------------------------------------- | -------------------------------------------------------------- | ------------------------------------------------------------- | --------------------------------------------------------------------------- |
-|                                                         | [빈 힙 예외처리](DataStructures/Heaps/EmptyHeapException.java) | [원형 연결리스트](DataStructures/Lists/CircleLinkedList.java) | [제너릭 어레이 리스트 큐](DataStructures/Queues/GenericArrayListQueue.java) |
-|                                                         | [힙](DataStructures/Heaps/Heap.java)                           | [이중 연결리스트](DataStructures/Lists/DoublyLinkedList.java) | [큐](DataStructures/Queues/Queues.java)                                     |
-| [그래프](DataStructures/Graphs/Graphs.java)             | [힙 요소](DataStructures/Heaps/HeapElement.java)               | [단순 연결리스트](DataStructures/Lists/SinglyLinkedList.java) |
-| [크루스칼 알고리즘](DataStructures/Graphs/Kruskal.java) | [최대힙](DataStructures/Heaps/MaxHeap.java)                    |
-| [행렬 그래프](DataStructures/Graphs/MatrixGraphs.java)  | [최소힙](DataStructures/Heaps/MinHeap.java)                    |
-| [프림 최소신장트리](DataStructures/Graphs/PrimMST.java) |
-
-| 스택                                                            | 트리                                              |
-| --------------------------------------------------------------- | ------------------------------------------------- |
-| [노드 스택](DataStructures/Stacks/NodeStack.java)               | [AVL 트리](DataStructures/Trees/AVLTree.java)     |
-| [연결리스트 스택](DataStructures/Stacks/StackOfLinkedList.java) | [이진 트리](DataStructures/Trees/BinaryTree.java) |
-| [스택](DataStructures/Stacks)                                   | And much more...                                  |
-
-- [Bags](DataStructures/Bags/Bag.java)
-- [Buffer](DataStructures/Buffers/CircularBuffer.java)
-- [HashMap](DataStructures/HashMap/Hashing/HashMap.java)
--

From 2ea3873b9ff15d64d6160715365aae7e6590958a Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 27 Jan 2026 00:46:45 +0100
Subject: [PATCH 1176/1338] chore(deps-dev): bump org.assertj:assertj-core from
 3.27.6 to 3.27.7 (#7243)

Bumps [org.assertj:assertj-core](https://github.com/assertj/assertj) from 3.27.6 to 3.27.7.
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](https://github.com/assertj/assertj/compare/assertj-build-3.27.6...assertj-build-3.27.7)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-version: 3.27.7
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 3f81e66d35c0..170e3900b77f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.27.6</assertj.version>
+        <assertj.version>3.27.7</assertj.version>
     </properties>
 
     <dependencyManagement>

From dc3d64f51d59268e9de8f2334a0327fb0bcbb957 Mon Sep 17 00:00:00 2001
From: Chahat Sandhu <chahat@disroot.org>
Date: Tue, 27 Jan 2026 15:29:05 -0600
Subject: [PATCH 1177/1338] feat: add Difference Array algorithm implementation
 and tests (#7244)

---
 .../prefixsum/DifferenceArray.java            |  87 ++++++++++++++
 .../prefixsum/DifferenceArrayTest.java        | 110 ++++++++++++++++++
 2 files changed, 197 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/prefixsum/DifferenceArray.java
 create mode 100644 src/test/java/com/thealgorithms/prefixsum/DifferenceArrayTest.java

diff --git a/src/main/java/com/thealgorithms/prefixsum/DifferenceArray.java b/src/main/java/com/thealgorithms/prefixsum/DifferenceArray.java
new file mode 100644
index 000000000000..1be55039cff0
--- /dev/null
+++ b/src/main/java/com/thealgorithms/prefixsum/DifferenceArray.java
@@ -0,0 +1,87 @@
+package com.thealgorithms.prefixsum;
+
+/**
+ * Implements the Difference Array algorithm.
+ *
+ * <p>
+ * The Difference Array is an auxiliary data structure that enables efficient range update operations.
+ * It is based on the mathematical concept of Finite Differences.
+ * </p>
+ *
+ * <p>
+ * <strong>Key Operations:</strong>
+ * <ul>
+ * <li>Range Update (Add value to [L, R]): O(1)</li>
+ * <li>Reconstruction (Prefix Sum): O(N)</li>
+ * </ul>
+ * </p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Finite_difference">Finite Difference (Wikipedia)</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Prefix_sum">Prefix Sum (Wikipedia)</a>
+ * @author Chahat Sandhu, <a href="https://github.com/singhc7">singhc7</a>
+ */
+public class DifferenceArray {
+
+    private final long[] differenceArray;
+    private final int n;
+
+    /**
+     * Initializes the Difference Array from a given integer array.
+     *
+     * @param inputArray The initial array. Cannot be null or empty.
+     * @throws IllegalArgumentException if the input array is null or empty.
+     */
+    public DifferenceArray(int[] inputArray) {
+        if (inputArray == null || inputArray.length == 0) {
+            throw new IllegalArgumentException("Input array cannot be null or empty.");
+        }
+        this.n = inputArray.length;
+        // Size n + 1 allows for branchless updates at the right boundary (r + 1).
+        this.differenceArray = new long[n + 1];
+        initializeDifferenceArray(inputArray);
+    }
+
+    private void initializeDifferenceArray(int[] inputArray) {
+        differenceArray[0] = inputArray[0];
+        for (int i = 1; i < n; i++) {
+            differenceArray[i] = inputArray[i] - inputArray[i - 1];
+        }
+    }
+
+    /**
+     * Adds a value to all elements in the range [l, r].
+     *
+     * <p>
+     * This method uses a branchless approach by allocating an extra element at the end
+     * of the array, avoiding the conditional check for the right boundary.
+     * </p>
+     *
+     * @param l   The starting index (inclusive).
+     * @param r   The ending index (inclusive).
+     * @param val The value to add.
+     * @throws IllegalArgumentException if the range is invalid.
+     */
+    public void update(int l, int r, int val) {
+        if (l < 0 || r >= n || l > r) {
+            throw new IllegalArgumentException(String.format("Invalid range: [%d, %d] for array of size %d", l, r, n));
+        }
+
+        differenceArray[l] += val;
+        differenceArray[r + 1] -= val;
+    }
+
+    /**
+     * Reconstructs the final array using prefix sums.
+     *
+     * @return The resulting array after all updates. Returns long[] to handle potential overflows.
+     */
+    public long[] getResultArray() {
+        long[] result = new long[n];
+        result[0] = differenceArray[0];
+
+        for (int i = 1; i < n; i++) {
+            result[i] = differenceArray[i] + result[i - 1];
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/prefixsum/DifferenceArrayTest.java b/src/test/java/com/thealgorithms/prefixsum/DifferenceArrayTest.java
new file mode 100644
index 000000000000..88a480f25f1a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/prefixsum/DifferenceArrayTest.java
@@ -0,0 +1,110 @@
+package com.thealgorithms.prefixsum;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class DifferenceArrayTest {
+
+    @Test
+    void testStandardRangeUpdate() {
+        int[] input = {10, 20, 30, 40, 50};
+        DifferenceArray da = new DifferenceArray(input);
+
+        da.update(1, 3, 5);
+
+        long[] expected = {10, 25, 35, 45, 50};
+        assertArrayEquals(expected, da.getResultArray());
+    }
+
+    @Test
+    void testMultipleOverlappingUpdates() {
+        int[] input = {10, 10, 10, 10, 10};
+        DifferenceArray da = new DifferenceArray(input);
+
+        da.update(0, 2, 10);
+        da.update(2, 4, 20);
+
+        long[] expected = {20, 20, 40, 30, 30};
+        assertArrayEquals(expected, da.getResultArray());
+    }
+
+    @Test
+    void testIntegerOverflowSafety() {
+        int[] input = {Integer.MAX_VALUE, 100};
+        DifferenceArray da = new DifferenceArray(input);
+
+        da.update(0, 0, 100);
+
+        long[] result = da.getResultArray();
+        long expectedVal = (long) Integer.MAX_VALUE + 100;
+
+        assertEquals(expectedVal, result[0]);
+    }
+
+    @Test
+    void testFullRangeUpdate() {
+        int[] input = {1, 2, 3};
+        DifferenceArray da = new DifferenceArray(input);
+
+        da.update(0, 2, 100);
+
+        long[] expected = {101, 102, 103};
+        assertArrayEquals(expected, da.getResultArray());
+    }
+
+    @Test
+    void testBoundaryWriteOptimization() {
+        int[] input = {5, 5};
+        DifferenceArray da = new DifferenceArray(input);
+
+        da.update(1, 1, 5);
+
+        long[] expected = {5, 10};
+
+        assertArrayEquals(expected, da.getResultArray());
+    }
+
+    @Test
+    void testLargeMassiveUpdate() {
+        int[] input = {0};
+        DifferenceArray da = new DifferenceArray(input);
+
+        int iterations = 100000;
+        for (int i = 0; i < iterations; i++) {
+            da.update(0, 0, 1);
+        }
+
+        assertEquals(100000L, da.getResultArray()[0]);
+    }
+
+    @Test
+    void testNullInputThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> new DifferenceArray(null));
+    }
+
+    @Test
+    void testEmptyInputThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> new DifferenceArray(new int[] {}));
+    }
+
+    @Test
+    void testInvalidRangeNegativeIndex() {
+        DifferenceArray da = new DifferenceArray(new int[] {1, 2, 3});
+        assertThrows(IllegalArgumentException.class, () -> da.update(-1, 1, 5));
+    }
+
+    @Test
+    void testInvalidRangeOutOfBounds() {
+        DifferenceArray da = new DifferenceArray(new int[] {1, 2, 3});
+        assertThrows(IllegalArgumentException.class, () -> da.update(0, 3, 5));
+    }
+
+    @Test
+    void testInvalidRangeStartGreaterThanEnd() {
+        DifferenceArray da = new DifferenceArray(new int[] {1, 2, 3});
+        assertThrows(IllegalArgumentException.class, () -> da.update(2, 1, 5));
+    }
+}

From 11eec787702199795249905d6f624b757f37cc07 Mon Sep 17 00:00:00 2001
From: Pranav Ghorpade <153404855+ghorpadeire@users.noreply.github.com>
Date: Fri, 30 Jan 2026 19:01:10 +0000
Subject: [PATCH 1178/1338] docs: Add comprehensive documentation to
 BinarySearch algorithm (#7245)

* docs: Add comprehensive documentation to BinarySearch algorithm

- Added detailed JavaDoc with @param, @return, @throws tags
- Included step-by-step algorithm walkthrough example
- Added inline comments explaining each code section
- Documented time and space complexity analysis
- Provided concrete usage examples with expected outputs
- Explained edge cases and overflow prevention technique

* style: Apply proper Java formatting to BinarySearch

- Fixed line length to meet style guidelines
- Applied proper JavaDoc formatting
- Corrected indentation and spacing
- Ensured compliance with project formatting standards

* fix: correct Javadoc formatting and add missing newline at EOF

- Fix Javadoc structure with proper tag ordering (description before @params)
- Remove incorrect @throws tag (method returns -1, doesn't throw)
- Format algorithm steps as proper HTML ordered list
- Move complexity analysis before @param tags
- Add missing newline at end of file
- Fix example code to use instance method call
---
 .../thealgorithms/searches/BinarySearch.java  | 114 ++++++++++++++----
 1 file changed, 90 insertions(+), 24 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/BinarySearch.java b/src/main/java/com/thealgorithms/searches/BinarySearch.java
index 0cac484d56b4..7a5361b280ea 100644
--- a/src/main/java/com/thealgorithms/searches/BinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/BinarySearch.java
@@ -3,14 +3,32 @@
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
 
 /**
- * Binary search is one of the most popular algorithms The algorithm finds the
- * position of a target value within a sorted array
- * IMPORTANT
- * This algorithm works correctly only if the input array is sorted
- * in ascending order.
- * <p>
- * Worst-case performance O(log n) Best-case performance O(1) Average
- * performance O(log n) Worst-case space complexity O(1)
+ * Binary Search Algorithm Implementation
+ *
+ * <p>Binary search is one of the most efficient searching algorithms for finding a target element
+ * in a SORTED array. It works by repeatedly dividing the search space in half, eliminating half of
+ * the remaining elements in each step.
+ *
+ * <p>IMPORTANT: This algorithm ONLY works correctly if the input array is sorted in ascending
+ * order.
+ *
+ * <p>Algorithm Overview: 1. Start with the entire array (left = 0, right = array.length - 1) 2.
+ * Calculate the middle index 3. Compare the middle element with the target: - If middle element
+ * equals target: Found! Return the index - If middle element is less than target: Search the right
+ * half - If middle element is greater than target: Search the left half 4. Repeat until element is
+ * found or search space is exhausted
+ *
+ * <p>Performance Analysis: - Best-case time complexity: O(1) - Element found at middle on first
+ * try - Average-case time complexity: O(log n) - Most common scenario - Worst-case time
+ * complexity: O(log n) - Element not found or at extreme end - Space complexity: O(1) - Only uses
+ * a constant amount of extra space
+ *
+ * <p>Example Walkthrough: Array: [1, 3, 5, 7, 9, 11, 13, 15, 17, 19] Target: 7
+ *
+ * <p>Step 1: left=0, right=9, mid=4, array[4]=9 (9 &gt; 7, search left half) Step 2: left=0,
+ * right=3, mid=1, array[1]=3 (3 &lt; 7, search right half) Step 3: left=2, right=3, mid=2,
+ * array[2]=5 (5 &lt; 7, search right half) Step 4: left=3, right=3, mid=3, array[3]=7 (Found!
+ * Return index 3)
  *
  * @author Varun Upadhyay (https://github.com/varunu28)
  * @author Podshivalov Nikita (https://github.com/nikitap492)
@@ -20,41 +38,89 @@
 class BinarySearch implements SearchAlgorithm {
 
     /**
-     * @param array is an array where the element should be found
-     * @param key is an element which should be found
-     * @param <T> is any comparable type
-     * @return index of the element
+     * Generic method to perform binary search on any comparable type. This is the main entry point
+     * for binary search operations.
+     *
+     * <p>Example Usage:
+     * <pre>
+     * Integer[] numbers = {1, 3, 5, 7, 9, 11};
+     * int result = new BinarySearch().find(numbers, 7);
+     * // result will be 3 (index of element 7)
+     *
+     * int notFound = new BinarySearch().find(numbers, 4);
+     * // notFound will be -1 (element 4 does not exist)
+     * </pre>
+     *
+     * @param <T> The type of elements in the array (must be Comparable)
+     * @param array The sorted array to search in (MUST be sorted in ascending order)
+     * @param key The element to search for
+     * @return The index of the key if found, -1 if not found or if array is null/empty
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
+        // Handle edge case: empty array
         if (array == null || array.length == 0) {
             return -1;
         }
+
+        // Delegate to the core search implementation
         return search(array, key, 0, array.length - 1);
     }
 
     /**
-     * This method implements the Generic Binary Search
+     * Core recursive implementation of binary search algorithm. This method divides the problem
+     * into smaller subproblems recursively.
+     *
+     * <p>How it works:
+     * <ol>
+     * <li>Calculate the middle index to avoid integer overflow</li>
+     * <li>Check if middle element matches the target</li>
+     * <li>If not, recursively search either left or right half</li>
+     * <li>Base case: left &gt; right means element not found</li>
+     * </ol>
+     *
+     * <p>Time Complexity: O(log n) because we halve the search space each time.
+     * Space Complexity: O(log n) due to recursive call stack.
      *
-     * @param array The array to make the binary search
-     * @param key The number you are looking for
-     * @param left The lower bound
-     * @param right The upper bound
-     * @return the location of the key
+     * @param <T> The type of elements (must be Comparable)
+     * @param array The sorted array to search in
+     * @param key The element we're looking for
+     * @param left The leftmost index of current search range (inclusive)
+     * @param right The rightmost index of current search range (inclusive)
+     * @return The index where key is located, or -1 if not found
      */
     private <T extends Comparable<T>> int search(T[] array, T key, int left, int right) {
+        // Base case: Search space is exhausted
+        // This happens when left pointer crosses right pointer
         if (right < left) {
-            return -1; // this means that the key not found
+            return -1; // Key not found in the array
         }
-        // find median
-        int median = (left + right) >>> 1;
+
+        // Calculate middle index
+        // Using (left + right) / 2 could cause integer overflow for large arrays
+        // So we use: left + (right - left) / 2 which is mathematically equivalent
+        // but prevents overflow
+        int median = (left + right) >>> 1; // Unsigned right shift is faster division by 2
+
+        // Get the value at middle position for comparison
         int comp = key.compareTo(array[median]);
 
+        // Case 1: Found the target element at middle position
         if (comp == 0) {
-            return median;
-        } else if (comp < 0) {
+            return median; // Return the index where element was found
+        }
+        // Case 2: Target is smaller than middle element
+        // This means if target exists, it must be in the LEFT half
+        else if (comp < 0) {
+            // Recursively search the left half
+            // New search range: [left, median - 1]
             return search(array, key, left, median - 1);
-        } else {
+        }
+        // Case 3: Target is greater than middle element
+        // This means if target exists, it must be in the RIGHT half
+        else {
+            // Recursively search the right half
+            // New search range: [median + 1, right]
             return search(array, key, median + 1, right);
         }
     }

From f3fd9ca3851c974afb7bfafc197a45d7e3678594 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 31 Jan 2026 19:32:08 +0100
Subject: [PATCH 1179/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.0.0 to 13.1.0 (#7251)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.0.0 to 13.1.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.0.0...checkstyle-13.1.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.1.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 170e3900b77f..65a8fc229647 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.0.0</version>
+                    <version>13.1.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From dfaa4956392b06bb2e55578e883213a9ea946b8f Mon Sep 17 00:00:00 2001
From: Divyansh Saxena <119129875+divyanshsaxena002@users.noreply.github.com>
Date: Sun, 1 Feb 2026 20:21:13 +0530
Subject: [PATCH 1180/1338] Refactor KMP and RabinKarp: Improve Reusability and
 Test Coverage (#7250)

* first commit

* Running KMPTest and RabinKarpTest with fixed formatting

* now build failed error resolved

* now build failed error resolved 2

---------

Co-authored-by: Divyansh Saxena <divyanshsaxena@gmail.com>
Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../java/com/thealgorithms/strings/KMP.java   | 27 +++++---
 .../com/thealgorithms/strings/RabinKarp.java  | 62 ++++++++-----------
 .../com/thealgorithms/strings/KMPTest.java    | 29 +++++++++
 .../thealgorithms/strings/RabinKarpTest.java  | 46 ++++++++++++++
 4 files changed, 119 insertions(+), 45 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/strings/KMPTest.java
 create mode 100644 src/test/java/com/thealgorithms/strings/RabinKarpTest.java

diff --git a/src/main/java/com/thealgorithms/strings/KMP.java b/src/main/java/com/thealgorithms/strings/KMP.java
index 07d3b0415006..0317abe6f39a 100644
--- a/src/main/java/com/thealgorithms/strings/KMP.java
+++ b/src/main/java/com/thealgorithms/strings/KMP.java
@@ -1,5 +1,8 @@
 package com.thealgorithms.strings;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * Implementation of Knuth–Morris–Pratt algorithm Usage: see the main function
  * for an example
@@ -8,16 +11,19 @@ public final class KMP {
     private KMP() {
     }
 
-    // a working example
-
-    public static void main(String[] args) {
-        final String haystack = "AAAAABAAABA"; // This is the full string
-        final String needle = "AAAA"; // This is the substring that we want to find
-        kmpMatcher(haystack, needle);
-    }
+    /**
+     * find the starting index in string haystack[] that matches the search word P[]
+     *
+     * @param haystack The text to be searched
+     * @param needle   The pattern to be searched for
+     * @return A list of starting indices where the pattern is found
+     */
+    public static List<Integer> kmpMatcher(final String haystack, final String needle) {
+        List<Integer> occurrences = new ArrayList<>();
+        if (haystack == null || needle == null || needle.isEmpty()) {
+            return occurrences;
+        }
 
-    // find the starting index in string haystack[] that matches the search word P[]
-    public static void kmpMatcher(final String haystack, final String needle) {
         final int m = haystack.length();
         final int n = needle.length();
         final int[] pi = computePrefixFunction(needle);
@@ -32,10 +38,11 @@ public static void kmpMatcher(final String haystack, final String needle) {
             }
 
             if (q == n) {
-                System.out.println("Pattern starts: " + (i + 1 - n));
+                occurrences.add(i + 1 - n);
                 q = pi[q - 1];
             }
         }
+        return occurrences;
     }
 
     // return the prefix function
diff --git a/src/main/java/com/thealgorithms/strings/RabinKarp.java b/src/main/java/com/thealgorithms/strings/RabinKarp.java
index bb8df3358453..be17f87c3656 100644
--- a/src/main/java/com/thealgorithms/strings/RabinKarp.java
+++ b/src/main/java/com/thealgorithms/strings/RabinKarp.java
@@ -1,32 +1,30 @@
 package com.thealgorithms.strings;
 
-import java.util.Scanner;
+import java.util.ArrayList;
+import java.util.List;
 
 /**
  * @author Prateek Kumar Oraon (https://github.com/prateekKrOraon)
  *
- An implementation of Rabin-Karp string matching algorithm
- Program will simply end if there is no match
+ *         An implementation of Rabin-Karp string matching algorithm
+ *         Program will simply end if there is no match
  */
 public final class RabinKarp {
     private RabinKarp() {
     }
 
-    public static Scanner scanner = null;
-    public static final int ALPHABET_SIZE = 256;
+    private static final int ALPHABET_SIZE = 256;
 
-    public static void main(String[] args) {
-        scanner = new Scanner(System.in);
-        System.out.println("Enter String");
-        String text = scanner.nextLine();
-        System.out.println("Enter pattern");
-        String pattern = scanner.nextLine();
-
-        int q = 101;
-        searchPat(text, pattern, q);
+    public static List<Integer> search(String text, String pattern) {
+        return search(text, pattern, 101);
     }
 
-    private static void searchPat(String text, String pattern, int q) {
+    public static List<Integer> search(String text, String pattern, int q) {
+        List<Integer> occurrences = new ArrayList<>();
+        if (text == null || pattern == null || pattern.isEmpty()) {
+            return occurrences;
+        }
+
         int m = pattern.length();
         int n = text.length();
         int t = 0;
@@ -35,48 +33,42 @@ private static void searchPat(String text, String pattern, int q) {
         int j = 0;
         int i = 0;
 
-        h = (int) Math.pow(ALPHABET_SIZE, m - 1) % q;
+        if (m > n) {
+            return new ArrayList<>();
+        }
+
+        // h = pow(ALPHABET_SIZE, m-1) % q
+        for (i = 0; i < m - 1; i++) {
+            h = h * ALPHABET_SIZE % q;
+        }
 
         for (i = 0; i < m; i++) {
-            // hash value is calculated for each character and then added with the hash value of the
-            // next character for pattern as well as the text for length equal to the length of
-            // pattern
             p = (ALPHABET_SIZE * p + pattern.charAt(i)) % q;
             t = (ALPHABET_SIZE * t + text.charAt(i)) % q;
         }
 
         for (i = 0; i <= n - m; i++) {
-            // if the calculated hash value of the pattern and text matches then
-            // all the characters of the pattern is matched with the text of length equal to length
-            // of the pattern if all matches then pattern exist in string if not then the hash value
-            // of the first character of the text is subtracted and hash value of the next character
-            // after the end of the evaluated characters is added
             if (p == t) {
-                // if hash value matches then the individual characters are matched
                 for (j = 0; j < m; j++) {
-                    // if not matched then break out of the loop
                     if (text.charAt(i + j) != pattern.charAt(j)) {
                         break;
                     }
                 }
 
-                // if all characters are matched then pattern exist in the string
                 if (j == m) {
-                    System.out.println("Pattern found at index " + i);
+                    occurrences.add(i);
                 }
             }
 
-            // if i<n-m then hash value of the first character of the text is subtracted and hash
-            // value of the next character after the end of the evaluated characters is added to get
-            // the hash value of the next window of characters in the text
             if (i < n - m) {
-                t = (ALPHABET_SIZE * (t - text.charAt(i) * h) + text.charAt(i + m)) % q;
-
-                // if hash value becomes less than zero than q is added to make it positive
+                t = (t - text.charAt(i) * h % q);
                 if (t < 0) {
-                    t = (t + q);
+                    t += q;
                 }
+                t = t * ALPHABET_SIZE % q;
+                t = (t + text.charAt(i + m)) % q;
             }
         }
+        return occurrences;
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/KMPTest.java b/src/test/java/com/thealgorithms/strings/KMPTest.java
new file mode 100644
index 000000000000..9fa5f398d420
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/KMPTest.java
@@ -0,0 +1,29 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class KMPTest {
+
+    @Test
+    public void testNullInputs() {
+        assertEquals(List.of(), KMP.kmpMatcher(null, "A"));
+        assertEquals(List.of(), KMP.kmpMatcher("A", null));
+        assertEquals(List.of(), KMP.kmpMatcher(null, null));
+    }
+
+    @Test
+    public void testKMPMatcher() {
+        assertEquals(List.of(0, 1), KMP.kmpMatcher("AAAAABAAABA", "AAAA"));
+        assertEquals(List.of(0, 3), KMP.kmpMatcher("ABCABC", "ABC"));
+        assertEquals(List.of(10), KMP.kmpMatcher("ABABDABACDABABCABAB", "ABABCABAB"));
+        assertEquals(List.of(), KMP.kmpMatcher("ABCDE", "FGH"));
+        assertEquals(List.of(), KMP.kmpMatcher("A", "AA"));
+        assertEquals(List.of(0, 1, 2), KMP.kmpMatcher("AAA", "A"));
+        assertEquals(List.of(0), KMP.kmpMatcher("A", "A"));
+        assertEquals(List.of(), KMP.kmpMatcher("", "A"));
+        assertEquals(List.of(), KMP.kmpMatcher("A", ""));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/RabinKarpTest.java b/src/test/java/com/thealgorithms/strings/RabinKarpTest.java
new file mode 100644
index 000000000000..6dfd099e9bca
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/RabinKarpTest.java
@@ -0,0 +1,46 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class RabinKarpTest {
+
+    @Test
+    public void testNullInputs() {
+        assertEquals(List.of(), RabinKarp.search(null, "A"));
+        assertEquals(List.of(), RabinKarp.search("A", null));
+        assertEquals(List.of(), RabinKarp.search(null, null));
+    }
+
+    @Test
+    public void testHashCollision() {
+        // 'a' = 97. (char)198 % 101 = 97.
+        // For length 1, h = 1. p = 97. t = 198 % 101 = 97.
+        // Collision occurs, loop checks characters: 198 != 97, breaks.
+        char collisionChar = (char) 198;
+        String text = String.valueOf(collisionChar);
+        String pattern = "a";
+        assertEquals(List.of(), RabinKarp.search(text, pattern));
+    }
+
+    @Test
+    public void testSearchWithCustomQ() {
+        // Using a different prime
+        assertEquals(List.of(0, 1), RabinKarp.search("AAAA", "AAA", 13));
+    }
+
+    @Test
+    public void testRabinKarpSearch() {
+        assertEquals(List.of(0, 1), RabinKarp.search("AAAAABAAABA", "AAAA"));
+        assertEquals(List.of(0, 3), RabinKarp.search("ABCABC", "ABC"));
+        assertEquals(List.of(10), RabinKarp.search("ABABDABACDABABCABAB", "ABABCABAB"));
+        assertEquals(List.of(), RabinKarp.search("ABCDE", "FGH"));
+        assertEquals(List.of(), RabinKarp.search("A", "AA"));
+        assertEquals(List.of(0, 1, 2), RabinKarp.search("AAA", "A"));
+        assertEquals(List.of(0), RabinKarp.search("A", "A"));
+        assertEquals(List.of(), RabinKarp.search("", "A"));
+        assertEquals(List.of(), RabinKarp.search("A", ""));
+    }
+}

From 3e36833bf4f3556061fcbefff9ae6458f7892e34 Mon Sep 17 00:00:00 2001
From: Ruturaj Jadhav <ruturajjadhav122@gmail.com>
Date: Sun, 1 Feb 2026 20:56:57 +0530
Subject: [PATCH 1181/1338] add Subarray Sum Equals K using prefix sum (#7252)

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../prefixsum/SubarraySumEqualsK.java         | 72 +++++++++++++++++++
 .../prefixsum/SubarraySumEqualskTest.java     | 59 +++++++++++++++
 2 files changed, 131 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/prefixsum/SubarraySumEqualsK.java
 create mode 100644 src/test/java/com/thealgorithms/prefixsum/SubarraySumEqualskTest.java

diff --git a/src/main/java/com/thealgorithms/prefixsum/SubarraySumEqualsK.java b/src/main/java/com/thealgorithms/prefixsum/SubarraySumEqualsK.java
new file mode 100644
index 000000000000..d6a6bbc01663
--- /dev/null
+++ b/src/main/java/com/thealgorithms/prefixsum/SubarraySumEqualsK.java
@@ -0,0 +1,72 @@
+package com.thealgorithms.prefixsum;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Implements an algorithm to count the number of continuous subarrays
+ * whose sum equals a given value k.
+ *
+ * <p>
+ * This algorithm uses the Prefix Sum technique combined with a HashMap
+ * to achieve O(N) time complexity.
+ * </p>
+ *
+ * <p>
+ * Let prefixSum[i] be the sum of elements from index 0 to i.
+ * A subarray (j + 1) to i has sum k if:
+ *
+ * <pre>
+ * prefixSum[i] - prefixSum[j] = k
+ * </pre>
+ * </p>
+ *
+ * <p>
+ * The HashMap stores the frequency of each prefix sum encountered so far.
+ * </p>
+ *
+ * <p>
+ * <strong>Time Complexity:</strong> O(N)<br>
+ * <strong>Space Complexity:</strong> O(N)
+ * </p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Prefix_sum">Prefix Sum (Wikipedia)</a>
+ * @author Ruturaj Jadhav, <a href="https://github.com/ruturajjadhav07">ruturajjadhav07</a>
+ */
+public final class SubarraySumEqualsK {
+
+    private SubarraySumEqualsK() {
+        // Utility class; prevent instantiation
+    }
+
+    /**
+     * Counts the number of subarrays whose sum equals k.
+     *
+     * @param nums The input integer array.
+     * @param k    The target sum.
+     * @return The number of continuous subarrays summing to k.
+     * @throws IllegalArgumentException if nums is null.
+     */
+    public static int countSubarrays(int[] nums, int k) {
+        if (nums == null) {
+            throw new IllegalArgumentException("Input array cannot be null");
+        }
+
+        Map<Long, Integer> prefixSumFrequency = new HashMap<>();
+        prefixSumFrequency.put(0L, 1);
+
+        long prefixSum = 0;
+        int count = 0;
+
+        for (int num : nums) {
+            prefixSum += num;
+
+            long requiredSum = prefixSum - k;
+            count += prefixSumFrequency.getOrDefault(requiredSum, 0);
+
+            prefixSumFrequency.put(prefixSum, prefixSumFrequency.getOrDefault(prefixSum, 0) + 1);
+        }
+
+        return count;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/prefixsum/SubarraySumEqualskTest.java b/src/test/java/com/thealgorithms/prefixsum/SubarraySumEqualskTest.java
new file mode 100644
index 000000000000..68f85b713046
--- /dev/null
+++ b/src/test/java/com/thealgorithms/prefixsum/SubarraySumEqualskTest.java
@@ -0,0 +1,59 @@
+package com.thealgorithms.prefixsum;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests for {@link SubarraySumEqualsK}.
+ */
+class SubarraySumEqualsKTest {
+
+    @Test
+    void testBasicExample() {
+        int[] nums = {1, 1, 1};
+        int k = 2;
+        assertEquals(2, SubarraySumEqualsK.countSubarrays(nums, k));
+    }
+
+    @Test
+    void testWithNegativeNumbers() {
+        int[] nums = {1, -1, 0};
+        int k = 0;
+        assertEquals(3, SubarraySumEqualsK.countSubarrays(nums, k));
+    }
+
+    @Test
+    void testSingleElementEqualToK() {
+        int[] nums = {5};
+        int k = 5;
+        assertEquals(1, SubarraySumEqualsK.countSubarrays(nums, k));
+    }
+
+    @Test
+    void testSingleElementNotEqualToK() {
+        int[] nums = {5};
+        int k = 3;
+        assertEquals(0, SubarraySumEqualsK.countSubarrays(nums, k));
+    }
+
+    @Test
+    void testAllZeros() {
+        int[] nums = {0, 0, 0};
+        int k = 0;
+        assertEquals(6, SubarraySumEqualsK.countSubarrays(nums, k));
+    }
+
+    @Test
+    void testEmptyArray() {
+        int[] nums = {};
+        int k = 0;
+        assertEquals(0, SubarraySumEqualsK.countSubarrays(nums, k));
+    }
+
+    @Test
+    void testNullArrayThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> SubarraySumEqualsK.countSubarrays(null, 0));
+    }
+}

From c6703d337edb74783406d5cafa4a363a2415d8eb Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 3 Feb 2026 10:55:55 +0100
Subject: [PATCH 1182/1338] chore(deps-dev): bump
 org.apache.maven.plugins:maven-compiler-plugin from 3.14.1 to 3.15.0 (#7254)

chore(deps-dev): bump org.apache.maven.plugins:maven-compiler-plugin

Bumps [org.apache.maven.plugins:maven-compiler-plugin](https://github.com/apache/maven-compiler-plugin) from 3.14.1 to 3.15.0.
- [Release notes](https://github.com/apache/maven-compiler-plugin/releases)
- [Commits](https://github.com/apache/maven-compiler-plugin/compare/maven-compiler-plugin-3.14.1...maven-compiler-plugin-3.15.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-compiler-plugin
  dependency-version: 3.15.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 65a8fc229647..f13169cece97 100644
--- a/pom.xml
+++ b/pom.xml
@@ -69,7 +69,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.14.1</version>
+                <version>3.15.0</version>
                 <configuration>
                     <release>21</release>
                     <compilerArgs>

From 8e30bcbb02f14f118cc63f24b3c44b7ff7f66ba8 Mon Sep 17 00:00:00 2001
From: Ahmed Allam <60698204+GziXnine@users.noreply.github.com>
Date: Tue, 3 Feb 2026 22:32:37 +0200
Subject: [PATCH 1183/1338] refactor: clean up duplicate algorithm
 implementations to reduce maintenance overhead (#7256)

refactor: remove duplicate algorithm implementations

Removed the following duplicate implementations:
- searches/PerfectBinarySearch.java (duplicate of IterativeBinarySearch)
- searches/SortOrderAgnosticBinarySearch.java (duplicate of OrderAgnosticBinarySearch)
- strings/LongestPalindromicSubstring.java (duplicate of dynamicprogramming version)
- strings/ValidParentheses.java (duplicate of stacks version)
- others/cn/HammingDistance.java (duplicate - strings version handles text)
- others/NewManShanksPrimeTest.java (orphan test in wrong package)

Updated DIRECTORY.md to reflect the changes.

Fixes #7253

Co-authored-by: Ahmed Allam <60698204+AllamF5J@users.noreply.github.com>
---
 DIRECTORY.md                                  | 13 ---
 .../others/cn/HammingDistance.java            | 32 --------
 .../searches/PerfectBinarySearch.java         | 54 ------------
 .../SortOrderAgnosticBinarySearch.java        | 30 -------
 .../strings/LongestPalindromicSubstring.java  | 37 ---------
 .../strings/ValidParentheses.java             | 53 ------------
 .../others/NewManShanksPrimeTest.java         | 49 -----------
 .../others/cn/HammingDistanceTest.java        | 82 -------------------
 .../searches/PerfectBinarySearchTest.java     | 44 ----------
 .../SortOrderAgnosticBinarySearchTest.java    | 26 ------
 .../LongestPalindromicSubstringTest.java      | 21 -----
 .../strings/ValidParenthesesTest.java         | 33 --------
 12 files changed, 474 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/others/cn/HammingDistance.java
 delete mode 100644 src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java
 delete mode 100644 src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java
 delete mode 100644 src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java
 delete mode 100644 src/main/java/com/thealgorithms/strings/ValidParentheses.java
 delete mode 100644 src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java
 delete mode 100644 src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java
 delete mode 100644 src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
 delete mode 100644 src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java
 delete mode 100644 src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java
 delete mode 100644 src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index deaf59636fa4..585c634c3429 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -626,8 +626,6 @@
           - 📄 [SkylineProblem](src/main/java/com/thealgorithms/others/SkylineProblem.java)
           - 📄 [TwoPointers](src/main/java/com/thealgorithms/others/TwoPointers.java)
           - 📄 [Verhoeff](src/main/java/com/thealgorithms/others/Verhoeff.java)
-          - 📁 **cn**
-            - 📄 [HammingDistance](src/main/java/com/thealgorithms/others/cn/HammingDistance.java)
         - 📁 **physics**
           - 📄 [CoulombsLaw](src/main/java/com/thealgorithms/physics/CoulombsLaw.java)
           - 📄 [DampedOscillator](src/main/java/com/thealgorithms/physics/DampedOscillator.java)
@@ -701,7 +699,6 @@
           - 📄 [LowerBound](src/main/java/com/thealgorithms/searches/LowerBound.java)
           - 📄 [MonteCarloTreeSearch](src/main/java/com/thealgorithms/searches/MonteCarloTreeSearch.java)
           - 📄 [OrderAgnosticBinarySearch](src/main/java/com/thealgorithms/searches/OrderAgnosticBinarySearch.java)
-          - 📄 [PerfectBinarySearch](src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java)
           - 📄 [QuickSelect](src/main/java/com/thealgorithms/searches/QuickSelect.java)
           - 📄 [RabinKarpAlgorithm](src/main/java/com/thealgorithms/searches/RabinKarpAlgorithm.java)
           - 📄 [RandomSearch](src/main/java/com/thealgorithms/searches/RandomSearch.java)
@@ -710,7 +707,6 @@
           - 📄 [SaddlebackSearch](src/main/java/com/thealgorithms/searches/SaddlebackSearch.java)
           - 📄 [SearchInARowAndColWiseSortedMatrix](src/main/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrix.java)
           - 📄 [SentinelLinearSearch](src/main/java/com/thealgorithms/searches/SentinelLinearSearch.java)
-          - 📄 [SortOrderAgnosticBinarySearch](src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java)
           - 📄 [SquareRootBinarySearch](src/main/java/com/thealgorithms/searches/SquareRootBinarySearch.java)
           - 📄 [TernarySearch](src/main/java/com/thealgorithms/searches/TernarySearch.java)
           - 📄 [UnionFind](src/main/java/com/thealgorithms/searches/UnionFind.java)
@@ -817,7 +813,6 @@
           - 📄 [LetterCombinationsOfPhoneNumber](src/main/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumber.java)
           - 📄 [LongestCommonPrefix](src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java)
           - 📄 [LongestNonRepetitiveSubstring](src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java)
-          - 📄 [LongestPalindromicSubstring](src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java)
           - 📄 [Lower](src/main/java/com/thealgorithms/strings/Lower.java)
           - 📄 [Manacher](src/main/java/com/thealgorithms/strings/Manacher.java)
           - 📄 [MyAtoi](src/main/java/com/thealgorithms/strings/MyAtoi.java)
@@ -834,7 +829,6 @@
           - 📄 [StringMatchFiniteAutomata](src/main/java/com/thealgorithms/strings/StringMatchFiniteAutomata.java)
           - 📄 [SuffixArray](src/main/java/com/thealgorithms/strings/SuffixArray.java)
           - 📄 [Upper](src/main/java/com/thealgorithms/strings/Upper.java)
-          - 📄 [ValidParentheses](src/main/java/com/thealgorithms/strings/ValidParentheses.java)
           - 📄 [WordLadder](src/main/java/com/thealgorithms/strings/WordLadder.java)
           - 📄 [ZAlgorithm](src/main/java/com/thealgorithms/strings/ZAlgorithm.java)
           - 📁 **zigZagPattern**
@@ -1395,7 +1389,6 @@
           - 📄 [MaximumSumOfDistinctSubarraysWithLengthKTest](src/test/java/com/thealgorithms/others/MaximumSumOfDistinctSubarraysWithLengthKTest.java)
           - 📄 [MiniMaxAlgorithmTest](src/test/java/com/thealgorithms/others/MiniMaxAlgorithmTest.java)
           - 📄 [MosAlgorithmTest](src/test/java/com/thealgorithms/others/MosAlgorithmTest.java)
-          - 📄 [NewManShanksPrimeTest](src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java)
           - 📄 [NextFitTest](src/test/java/com/thealgorithms/others/NextFitTest.java)
           - 📄 [PageRankTest](src/test/java/com/thealgorithms/others/PageRankTest.java)
           - 📄 [PasswordGenTest](src/test/java/com/thealgorithms/others/PasswordGenTest.java)
@@ -1404,8 +1397,6 @@
           - 📄 [SkylineProblemTest](src/test/java/com/thealgorithms/others/SkylineProblemTest.java)
           - 📄 [TwoPointersTest](src/test/java/com/thealgorithms/others/TwoPointersTest.java)
           - 📄 [WorstFitCPUTest](src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)
-          - 📁 **cn**
-            - 📄 [HammingDistanceTest](src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java)
         - 📁 **physics**
           - 📄 [CoulombsLawTest](src/test/java/com/thealgorithms/physics/CoulombsLawTest.java)
           - 📄 [DampedOscillatorTest](src/test/java/com/thealgorithms/physics/DampedOscillatorTest.java)
@@ -1479,7 +1470,6 @@
           - 📄 [LowerBoundTest](src/test/java/com/thealgorithms/searches/LowerBoundTest.java)
           - 📄 [MonteCarloTreeSearchTest](src/test/java/com/thealgorithms/searches/MonteCarloTreeSearchTest.java)
           - 📄 [OrderAgnosticBinarySearchTest](src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java)
-          - 📄 [PerfectBinarySearchTest](src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java)
           - 📄 [QuickSelectTest](src/test/java/com/thealgorithms/searches/QuickSelectTest.java)
           - 📄 [RabinKarpAlgorithmTest](src/test/java/com/thealgorithms/searches/RabinKarpAlgorithmTest.java)
           - 📄 [RandomSearchTest](src/test/java/com/thealgorithms/searches/RandomSearchTest.java)
@@ -1488,7 +1478,6 @@
           - 📄 [SaddlebackSearchTest](src/test/java/com/thealgorithms/searches/SaddlebackSearchTest.java)
           - 📄 [SearchInARowAndColWiseSortedMatrixTest](src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java)
           - 📄 [SentinelLinearSearchTest](src/test/java/com/thealgorithms/searches/SentinelLinearSearchTest.java)
-          - 📄 [SortOrderAgnosticBinarySearchTest](src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
           - 📄 [SquareRootBinarySearchTest](src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java)
           - 📄 [TernarySearchTest](src/test/java/com/thealgorithms/searches/TernarySearchTest.java)
           - 📄 [TestSearchInARowAndColWiseSortedMatrix](src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
@@ -1593,7 +1582,6 @@
           - 📄 [LetterCombinationsOfPhoneNumberTest](src/test/java/com/thealgorithms/strings/LetterCombinationsOfPhoneNumberTest.java)
           - 📄 [LongestCommonPrefixTest](src/test/java/com/thealgorithms/strings/LongestCommonPrefixTest.java)
           - 📄 [LongestNonRepetitiveSubstringTest](src/test/java/com/thealgorithms/strings/LongestNonRepetitiveSubstringTest.java)
-          - 📄 [LongestPalindromicSubstringTest](src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java)
           - 📄 [LowerTest](src/test/java/com/thealgorithms/strings/LowerTest.java)
           - 📄 [ManacherTest](src/test/java/com/thealgorithms/strings/ManacherTest.java)
           - 📄 [MyAtoiTest](src/test/java/com/thealgorithms/strings/MyAtoiTest.java)
@@ -1609,7 +1597,6 @@
           - 📄 [StringMatchFiniteAutomataTest](src/test/java/com/thealgorithms/strings/StringMatchFiniteAutomataTest.java)
           - 📄 [SuffixArrayTest](src/test/java/com/thealgorithms/strings/SuffixArrayTest.java)
           - 📄 [UpperTest](src/test/java/com/thealgorithms/strings/UpperTest.java)
-          - 📄 [ValidParenthesesTest](src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java)
           - 📄 [WordLadderTest](src/test/java/com/thealgorithms/strings/WordLadderTest.java)
           - 📄 [ZAlgorithmTest](src/test/java/com/thealgorithms/strings/ZAlgorithmTest.java)
           - 📁 **zigZagPattern**
diff --git a/src/main/java/com/thealgorithms/others/cn/HammingDistance.java b/src/main/java/com/thealgorithms/others/cn/HammingDistance.java
deleted file mode 100644
index c8239d53d606..000000000000
--- a/src/main/java/com/thealgorithms/others/cn/HammingDistance.java
+++ /dev/null
@@ -1,32 +0,0 @@
-package com.thealgorithms.others.cn;
-
-public final class HammingDistance {
-    private HammingDistance() {
-    }
-
-    private static void checkChar(char inChar) {
-        if (inChar != '0' && inChar != '1') {
-            throw new IllegalArgumentException("Input must be a binary string.");
-        }
-    }
-
-    public static int compute(char charA, char charB) {
-        checkChar(charA);
-        checkChar(charB);
-        return charA == charB ? 0 : 1;
-    }
-
-    public static int compute(String bitsStrA, String bitsStrB) {
-        if (bitsStrA.length() != bitsStrB.length()) {
-            throw new IllegalArgumentException("Input strings must have the same length.");
-        }
-
-        int totalErrorBitCount = 0;
-
-        for (int i = 0; i < bitsStrA.length(); i++) {
-            totalErrorBitCount += compute(bitsStrA.charAt(i), bitsStrB.charAt(i));
-        }
-
-        return totalErrorBitCount;
-    }
-}
diff --git a/src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java b/src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java
deleted file mode 100644
index 495e2e41bc5b..000000000000
--- a/src/main/java/com/thealgorithms/searches/PerfectBinarySearch.java
+++ /dev/null
@@ -1,54 +0,0 @@
-package com.thealgorithms.searches;
-
-import com.thealgorithms.devutils.searches.SearchAlgorithm;
-
-/**
- * Binary search is one of the most popular algorithms The algorithm finds the
- * position of a target value within a sorted array
- *
- * <p>
- * Worst-case performance O(log n) Best-case performance O(1) Average
- * performance O(log n) Worst-case space complexity O(1)
- *
- * @author D Sunil (https://github.com/sunilnitdgp)
- * @see SearchAlgorithm
- */
-
-public class PerfectBinarySearch<T> implements SearchAlgorithm {
-
-    /**
-     * @param array is an array where the element should be found
-     * @param key is an element which should be found
-     * @param <T> is any comparable type
-     * @return index of the element
-     */
-    @Override
-    public <T extends Comparable<T>> int find(T[] array, T key) {
-        return search(array, key, 0, array.length - 1);
-    }
-
-    /**
-     * This method implements the Generic Binary Search iteratively.
-     *
-     * @param array The array to make the binary search
-     * @param key   The number you are looking for
-     * @return the location of the key, or -1 if not found
-     */
-    private static <T extends Comparable<T>> int search(T[] array, T key, int left, int right) {
-        while (left <= right) {
-            int median = (left + right) >>> 1;
-            int comp = key.compareTo(array[median]);
-
-            if (comp == 0) {
-                return median; // Key found
-            }
-
-            if (comp < 0) {
-                right = median - 1; // Adjust the right bound
-            } else {
-                left = median + 1; // Adjust the left bound
-            }
-        }
-        return -1; // Key not found
-    }
-}
diff --git a/src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java b/src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java
deleted file mode 100644
index 6a2a46c2821f..000000000000
--- a/src/main/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearch.java
+++ /dev/null
@@ -1,30 +0,0 @@
-package com.thealgorithms.searches;
-public final class SortOrderAgnosticBinarySearch {
-    private SortOrderAgnosticBinarySearch() {
-    }
-    public static int find(int[] arr, int key) {
-        int start = 0;
-        int end = arr.length - 1;
-        boolean arrDescending = arr[start] > arr[end]; // checking for Array is in ascending order or descending order.
-        while (start <= end) {
-            int mid = end - start / 2;
-            if (arr[mid] == key) {
-                return mid;
-            }
-            if (arrDescending) { // boolean is true then our array is in descending order
-                if (key < arr[mid]) {
-                    start = mid + 1;
-                } else {
-                    end = mid - 1;
-                }
-            } else { // otherwise our array is in ascending order
-                if (key > arr[mid]) {
-                    start = mid + 1;
-                } else {
-                    end = mid - 1;
-                }
-            }
-        }
-        return -1;
-    }
-}
diff --git a/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java b/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java
deleted file mode 100644
index ca500357ba77..000000000000
--- a/src/main/java/com/thealgorithms/strings/LongestPalindromicSubstring.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package com.thealgorithms.strings;
-
-final class LongestPalindromicSubstring {
-    private LongestPalindromicSubstring() {
-    }
-
-    /**
-     * Finds the longest palindromic substring in the given string.
-     *
-     * @param s the input string
-     * @return the longest palindromic substring
-     */
-    public static String longestPalindrome(String s) {
-        if (s == null || s.isEmpty()) {
-            return "";
-        }
-        String maxStr = "";
-        for (int i = 0; i < s.length(); ++i) {
-            for (int j = i; j < s.length(); ++j) {
-                if (isValid(s, i, j) && (j - i + 1 > maxStr.length())) {
-                    maxStr = s.substring(i, j + 1);
-                }
-            }
-        }
-        return maxStr;
-    }
-
-    private static boolean isValid(String s, int lo, int hi) {
-        int n = hi - lo + 1;
-        for (int i = 0; i < n / 2; ++i) {
-            if (s.charAt(lo + i) != s.charAt(hi - i)) {
-                return false;
-            }
-        }
-        return true;
-    }
-}
diff --git a/src/main/java/com/thealgorithms/strings/ValidParentheses.java b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
deleted file mode 100644
index 25a72f379dec..000000000000
--- a/src/main/java/com/thealgorithms/strings/ValidParentheses.java
+++ /dev/null
@@ -1,53 +0,0 @@
-package com.thealgorithms.strings;
-
-import java.util.ArrayDeque;
-import java.util.Deque;
-import java.util.Map;
-
-/**
- * Validates if a given string has valid matching parentheses.
- * <p>
- * A string is considered valid if:
- * <ul>
- *     <li>Open brackets are closed by the same type of brackets.</li>
- *     <li>Brackets are closed in the correct order.</li>
- *     <li>Every closing bracket has a corresponding open bracket of the same type.</li>
- * </ul>
- *
- * Allowed characters: '(', ')', '{', '}', '[', ']'
- */
-public final class ValidParentheses {
-    private ValidParentheses() {
-    }
-
-    private static final Map<Character, Character> BRACKET_PAIRS = Map.of(')', '(', '}', '{', ']', '[');
-
-    /**
-     * Checks if the input string has valid parentheses.
-     *
-     * @param s the string containing only bracket characters
-     * @return true if valid, false otherwise
-     * @throws IllegalArgumentException if the string contains invalid characters or is null
-     */
-    public static boolean isValid(String s) {
-        if (s == null) {
-            throw new IllegalArgumentException("Input string cannot be null");
-        }
-
-        Deque<Character> stack = new ArrayDeque<>();
-
-        for (char c : s.toCharArray()) {
-            if (BRACKET_PAIRS.containsValue(c)) {
-                stack.push(c); // opening bracket
-            } else if (BRACKET_PAIRS.containsKey(c)) {
-                if (stack.isEmpty() || stack.pop() != BRACKET_PAIRS.get(c)) {
-                    return false;
-                }
-            } else {
-                throw new IllegalArgumentException("Unexpected character: " + c);
-            }
-        }
-
-        return stack.isEmpty();
-    }
-}
diff --git a/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java b/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java
deleted file mode 100644
index 3b657e441b1c..000000000000
--- a/src/test/java/com/thealgorithms/others/NewManShanksPrimeTest.java
+++ /dev/null
@@ -1,49 +0,0 @@
-package com.thealgorithms.others;
-
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
-import com.thealgorithms.dynamicprogramming.NewManShanksPrime;
-import org.junit.jupiter.api.Test;
-
-public class NewManShanksPrimeTest {
-
-    @Test
-    void testOne() {
-        assertTrue(NewManShanksPrime.nthManShanksPrime(1, 1));
-    }
-
-    @Test
-    void testTwo() {
-        assertTrue(NewManShanksPrime.nthManShanksPrime(2, 3));
-    }
-
-    @Test
-    void testThree() {
-        assertTrue(NewManShanksPrime.nthManShanksPrime(3, 7));
-    }
-
-    @Test
-    void testFour() {
-        assertTrue(NewManShanksPrime.nthManShanksPrime(4, 17));
-    }
-
-    @Test
-    void testFive() {
-        assertTrue(NewManShanksPrime.nthManShanksPrime(5, 41));
-    }
-
-    @Test
-    void testSix() {
-        assertTrue(NewManShanksPrime.nthManShanksPrime(6, 99));
-    }
-
-    @Test
-    void testSeven() {
-        assertTrue(NewManShanksPrime.nthManShanksPrime(7, 239));
-    }
-
-    @Test
-    void testEight() {
-        assertTrue(NewManShanksPrime.nthManShanksPrime(8, 577));
-    }
-}
diff --git a/src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java b/src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java
deleted file mode 100644
index 669f928cd247..000000000000
--- a/src/test/java/com/thealgorithms/others/cn/HammingDistanceTest.java
+++ /dev/null
@@ -1,82 +0,0 @@
-package com.thealgorithms.others.cn;
-
-import org.assertj.core.api.Assertions;
-import org.junit.jupiter.api.Test;
-
-public class HammingDistanceTest {
-    @Test
-    public void checkForDifferentBits() {
-        int answer = HammingDistance.compute("000", "011");
-        Assertions.assertThat(answer).isEqualTo(2);
-    }
-
-    /*
-
-    1 0 1 0 1
-    1 1 1 1 0
-    ----------
-    0 1 0 1 1
-
-
- */
-    @Test
-    public void checkForDifferentBitsLength() {
-        int answer = HammingDistance.compute("10101", "11110");
-        Assertions.assertThat(answer).isEqualTo(3);
-    }
-
-    @Test
-    public void checkForSameBits() {
-        String someBits = "111";
-        int answer = HammingDistance.compute(someBits, someBits);
-        Assertions.assertThat(answer).isEqualTo(0);
-    }
-
-    @Test
-    public void checkForLongDataBits() {
-        int answer = HammingDistance.compute("10010101101010000100110100", "00110100001011001100110101");
-        Assertions.assertThat(answer).isEqualTo(7);
-    }
-
-    @Test
-    public void mismatchDataBits() {
-        Exception ex = org.junit.jupiter.api.Assertions.assertThrows(IllegalArgumentException.class, () -> { HammingDistance.compute("100010", "00011"); });
-
-        Assertions.assertThat(ex.getMessage()).contains("must have the same length");
-    }
-
-    @Test
-    public void mismatchDataBits2() {
-        Exception ex = org.junit.jupiter.api.Assertions.assertThrows(IllegalArgumentException.class, () -> { HammingDistance.compute("1", "11"); });
-
-        Assertions.assertThat(ex.getMessage()).contains("must have the same length");
-    }
-
-    @Test
-    public void checkForLongDataBitsSame() {
-        String someBits = "10010101101010000100110100";
-        int answer = HammingDistance.compute(someBits, someBits);
-        Assertions.assertThat(answer).isEqualTo(0);
-    }
-
-    @Test
-    public void checkForEmptyInput() {
-        String someBits = "";
-        int answer = HammingDistance.compute(someBits, someBits);
-        Assertions.assertThat(answer).isEqualTo(0);
-    }
-
-    @Test
-    public void checkForInputOfLength1() {
-        String someBits = "0";
-        int answer = HammingDistance.compute(someBits, someBits);
-        Assertions.assertThat(answer).isEqualTo(0);
-    }
-
-    @Test
-    public void computeThrowsExceptionWhenInputsAreNotBitStrs() {
-        Exception ex = org.junit.jupiter.api.Assertions.assertThrows(IllegalArgumentException.class, () -> { HammingDistance.compute("1A", "11"); });
-
-        Assertions.assertThat(ex.getMessage()).contains("must be a binary string");
-    }
-}
diff --git a/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
deleted file mode 100644
index 6eab20f45467..000000000000
--- a/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java
+++ /dev/null
@@ -1,44 +0,0 @@
-package com.thealgorithms.searches;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.api.Test;
-
-/**
- * @author D Sunil (https://github.com/sunilnitdgp)
- * @see PerfectBinarySearch
- */
-public class PerfectBinarySearchTest {
-
-    @Test
-    public void testIntegerBinarySearch() {
-        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
-        PerfectBinarySearch<Integer> binarySearch = new PerfectBinarySearch<>();
-
-        // Test cases for elements present in the array
-        assertEquals(0, binarySearch.find(array, 1)); // First element
-        assertEquals(4, binarySearch.find(array, 5)); // Middle element
-        assertEquals(9, binarySearch.find(array, 10)); // Last element
-        assertEquals(6, binarySearch.find(array, 7)); // Element in the middle
-
-        // Test cases for elements not in the array
-        assertEquals(-1, binarySearch.find(array, 0)); // Element before the array
-        assertEquals(-1, binarySearch.find(array, 11)); // Element after the array
-        assertEquals(-1, binarySearch.find(array, 100)); // Element not in the array
-    }
-
-    @Test
-    public void testStringBinarySearch() {
-        String[] array = {"apple", "banana", "cherry", "date", "fig"};
-        PerfectBinarySearch<String> binarySearch = new PerfectBinarySearch<>();
-
-        // Test cases for elements not in the array
-        assertEquals(-1, binarySearch.find(array, "apricot")); // Element not in the array
-        assertEquals(-1, binarySearch.find(array, "bananaa")); // Element not in the array
-
-        // Test cases for elements present in the array
-        assertEquals(0, binarySearch.find(array, "apple")); // First element
-        assertEquals(2, binarySearch.find(array, "cherry")); // Middle element
-        assertEquals(4, binarySearch.find(array, "fig")); // Last element
-    }
-}
diff --git a/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java
deleted file mode 100644
index e2917733d1d9..000000000000
--- a/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java
+++ /dev/null
@@ -1,26 +0,0 @@
-package com.thealgorithms.searches;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.api.Test;
-
-public class SortOrderAgnosticBinarySearchTest {
-
-    @Test
-    public void testAscending() {
-        int[] arr = {1, 2, 3, 4, 5}; // for ascending order.
-        int target = 2;
-        int ans = SortOrderAgnosticBinarySearch.find(arr, target);
-        int excepted = 1;
-        assertEquals(excepted, ans);
-    }
-
-    @Test
-    public void testDescending() {
-        int[] arr = {5, 4, 3, 2, 1}; // for descending order.
-        int target = 2;
-        int ans = SortOrderAgnosticBinarySearch.find(arr, target);
-        int excepted = 3;
-        assertEquals(excepted, ans);
-    }
-}
diff --git a/src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java b/src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java
deleted file mode 100644
index aa13c0f4a474..000000000000
--- a/src/test/java/com/thealgorithms/strings/LongestPalindromicSubstringTest.java
+++ /dev/null
@@ -1,21 +0,0 @@
-package com.thealgorithms.strings;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import java.util.stream.Stream;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.Arguments;
-import org.junit.jupiter.params.provider.MethodSource;
-
-class LongestPalindromicSubstringTest {
-
-    @ParameterizedTest
-    @MethodSource("provideTestCasesForLongestPalindrome")
-    void testLongestPalindrome(String input, String expected) {
-        assertEquals(expected, LongestPalindromicSubstring.longestPalindrome(input));
-    }
-
-    private static Stream<Arguments> provideTestCasesForLongestPalindrome() {
-        return Stream.of(Arguments.of("babad", "bab"), Arguments.of("cbbd", "bb"), Arguments.of("a", "a"), Arguments.of("", ""), Arguments.of("abc", "a"), Arguments.of(null, ""), Arguments.of("aaaaa", "aaaaa"));
-    }
-}
diff --git a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java b/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
deleted file mode 100644
index 411b11e743b8..000000000000
--- a/src/test/java/com/thealgorithms/strings/ValidParenthesesTest.java
+++ /dev/null
@@ -1,33 +0,0 @@
-package com.thealgorithms.strings;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
-import org.junit.jupiter.api.Test;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.CsvSource;
-
-public class ValidParenthesesTest {
-
-    @ParameterizedTest(name = "Input: \"{0}\" → Expected: {1}")
-    @CsvSource({"'()', true", "'()[]{}', true", "'(]', false", "'{[]}', true", "'([{}])', true", "'([)]', false", "'', true", "'(', false", "')', false", "'{{{{}}}}', true", "'[({})]', true", "'[(])', false", "'[', false", "']', false", "'()()()()', true", "'(()', false", "'())', false",
-        "'{[()()]()}', true"})
-    void
-    testIsValid(String input, boolean expected) {
-        assertEquals(expected, ValidParentheses.isValid(input));
-    }
-
-    @Test
-    void testNullInputThrows() {
-        IllegalArgumentException ex = assertThrows(IllegalArgumentException.class, () -> ValidParentheses.isValid(null));
-        assertEquals("Input string cannot be null", ex.getMessage());
-    }
-
-    @ParameterizedTest(name = "Input: \"{0}\" → throws IllegalArgumentException")
-    @CsvSource({"'a'", "'()a'", "'[123]'", "'{hello}'", "'( )'", "'\t'", "'\n'", "'@#$%'"})
-    void testInvalidCharactersThrow(String input) {
-        IllegalArgumentException ex = assertThrows(IllegalArgumentException.class, () -> ValidParentheses.isValid(input));
-        assertTrue(ex.getMessage().startsWith("Unexpected character"));
-    }
-}

From a14b2345f0a40a043ce78ebaf1ff056bbb362891 Mon Sep 17 00:00:00 2001
From: Chahat Sandhu <chahat@disroot.org>
Date: Wed, 4 Feb 2026 09:49:15 -0600
Subject: [PATCH 1184/1338] feat: add ElGamalCipher with Safe Prime generation
 and stateless design (#7257)

---
 .../thealgorithms/ciphers/ElGamalCipher.java  | 174 ++++++++++++++++++
 .../ciphers/ElGamalCipherTest.java            | 145 +++++++++++++++
 2 files changed, 319 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/ciphers/ElGamalCipher.java
 create mode 100644 src/test/java/com/thealgorithms/ciphers/ElGamalCipherTest.java

diff --git a/src/main/java/com/thealgorithms/ciphers/ElGamalCipher.java b/src/main/java/com/thealgorithms/ciphers/ElGamalCipher.java
new file mode 100644
index 000000000000..6383caa59b1f
--- /dev/null
+++ b/src/main/java/com/thealgorithms/ciphers/ElGamalCipher.java
@@ -0,0 +1,174 @@
+package com.thealgorithms.ciphers;
+
+import java.math.BigInteger;
+import java.security.SecureRandom;
+
+/**
+ * ElGamal Encryption Algorithm Implementation.
+ *
+ * <p>
+ * ElGamal is an asymmetric key encryption algorithm for public-key cryptography
+ * based on the Diffie–Hellman key exchange. It relies on the difficulty
+ * of computing discrete logarithms in a cyclic group.
+ * </p>
+ *
+ * <p>
+ * <strong>Key Features:</strong>
+ * <ul>
+ * <li>Uses Safe Primes (p = 2q + 1) to ensure group security.</li>
+ * <li>Verifies the generator is a primitive root modulo p.</li>
+ * <li>Stateless design using Java Records.</li>
+ * <li>SecureRandom for all cryptographic operations.</li>
+ * </ul>
+ * </p>
+ *
+ * @author Chahat Sandhu, <a href="https://github.com/singhc7">singhc7</a>
+ * @see <a href="https://en.wikipedia.org/wiki/ElGamal_encryption">ElGamal Encryption (Wikipedia)</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Safe_and_Sophie_Germain_primes">Safe Primes</a>
+ */
+public final class ElGamalCipher {
+
+    private static final SecureRandom RANDOM = new SecureRandom();
+    private static final int PRIME_CERTAINTY = 40;
+    private static final int MIN_BIT_LENGTH = 256;
+
+    private ElGamalCipher() {
+    }
+
+    /**
+     * A container for the Public and Private keys.
+     *
+     * @param p The prime modulus.
+     * @param g The generator (primitive root).
+     * @param y The public key component (g^x mod p).
+     * @param x The private key.
+     */
+    public record KeyPair(BigInteger p, BigInteger g, BigInteger y, BigInteger x) {
+    }
+
+    /**
+     * Container for the encryption result.
+     *
+     * @param a The first component (g^k mod p).
+     * @param b The second component (y^k * m mod p).
+     */
+    public record CipherText(BigInteger a, BigInteger b) {
+    }
+
+    /**
+     * Generates a valid ElGamal KeyPair using a Safe Prime.
+     *
+     * @param bitLength The bit length of the prime modulus p. Must be at least 256.
+     * @return A valid KeyPair (p, g, y, x).
+     * @throws IllegalArgumentException if bitLength is too small.
+     */
+    public static KeyPair generateKeys(int bitLength) {
+        if (bitLength < MIN_BIT_LENGTH) {
+            throw new IllegalArgumentException("Bit length must be at least " + MIN_BIT_LENGTH + " for security.");
+        }
+
+        BigInteger p;
+        BigInteger q;
+        BigInteger g;
+        BigInteger x;
+        BigInteger y;
+
+        // Generate Safe Prime p = 2q + 1
+        do {
+            q = new BigInteger(bitLength - 1, PRIME_CERTAINTY, RANDOM);
+            p = q.multiply(BigInteger.TWO).add(BigInteger.ONE);
+        } while (!p.isProbablePrime(PRIME_CERTAINTY));
+
+        // Find a Generator g (Primitive Root modulo p)
+        do {
+            g = new BigInteger(bitLength, RANDOM).mod(p.subtract(BigInteger.TWO)).add(BigInteger.TWO);
+        } while (!isValidGenerator(g, p, q));
+
+        // Generate Private Key x in range [2, p-2]
+        do {
+            x = new BigInteger(bitLength, RANDOM);
+        } while (x.compareTo(BigInteger.TWO) < 0 || x.compareTo(p.subtract(BigInteger.TWO)) > 0);
+
+        // Compute Public Key y = g^x mod p
+        y = g.modPow(x, p);
+
+        return new KeyPair(p, g, y, x);
+    }
+
+    /**
+     * Encrypts a message using the public key.
+     *
+     * @param message The message converted to BigInteger.
+     * @param p       The prime modulus.
+     * @param g       The generator.
+     * @param y       The public key component.
+     * @return The CipherText pair (a, b).
+     * @throws IllegalArgumentException if inputs are null, negative, or message >= p.
+     */
+    public static CipherText encrypt(BigInteger message, BigInteger p, BigInteger g, BigInteger y) {
+        if (message == null || p == null || g == null || y == null) {
+            throw new IllegalArgumentException("Inputs cannot be null.");
+        }
+        if (message.compareTo(BigInteger.ZERO) < 0) {
+            throw new IllegalArgumentException("Message must be non-negative.");
+        }
+        if (message.compareTo(p) >= 0) {
+            throw new IllegalArgumentException("Message must be smaller than the prime modulus p.");
+        }
+
+        BigInteger k;
+        BigInteger pMinus1 = p.subtract(BigInteger.ONE);
+
+        // Select ephemeral key k such that 1 < k < p-1 and gcd(k, p-1) = 1
+        do {
+            k = new BigInteger(p.bitLength(), RANDOM);
+        } while (k.compareTo(BigInteger.ONE) <= 0 || k.compareTo(pMinus1) >= 0 || !k.gcd(pMinus1).equals(BigInteger.ONE));
+
+        BigInteger a = g.modPow(k, p);
+        BigInteger b = y.modPow(k, p).multiply(message).mod(p);
+
+        return new CipherText(a, b);
+    }
+
+    /**
+     * Decrypts a ciphertext using the private key.
+     *
+     * @param cipher The CipherText (a, b).
+     * @param x      The private key.
+     * @param p      The prime modulus.
+     * @return The decrypted message as BigInteger.
+     * @throws IllegalArgumentException if inputs are null.
+     */
+    public static BigInteger decrypt(CipherText cipher, BigInteger x, BigInteger p) {
+        if (cipher == null || x == null || p == null) {
+            throw new IllegalArgumentException("Inputs cannot be null.");
+        }
+
+        BigInteger a = cipher.a();
+        BigInteger b = cipher.b();
+
+        BigInteger s = a.modPow(x, p);
+        BigInteger sInverse = s.modInverse(p);
+
+        return b.multiply(sInverse).mod(p);
+    }
+
+    /**
+     * Verifies if g is a valid generator for safe prime p = 2q + 1.
+     *
+     * @param g The candidate generator.
+     * @param p The safe prime.
+     * @param q The Sophie Germain prime (p-1)/2.
+     * @return True if g is a primitive root, False otherwise.
+     */
+    private static boolean isValidGenerator(BigInteger g, BigInteger p, BigInteger q) {
+        // Fix: Must use braces {} for all if statements
+        if (g.equals(BigInteger.ONE)) {
+            return false;
+        }
+        if (g.modPow(BigInteger.TWO, p).equals(BigInteger.ONE)) {
+            return false;
+        }
+        return !g.modPow(q, p).equals(BigInteger.ONE);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/ciphers/ElGamalCipherTest.java b/src/test/java/com/thealgorithms/ciphers/ElGamalCipherTest.java
new file mode 100644
index 000000000000..63dec4846bbc
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/ElGamalCipherTest.java
@@ -0,0 +1,145 @@
+package com.thealgorithms.ciphers;
+
+import java.math.BigInteger;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+/**
+ * Unit tests for ElGamalCipher.
+ * Includes property-based testing (homomorphism), probabilistic checks,
+ * and boundary validation.
+ */
+class ElGamalCipherTest {
+
+    private static ElGamalCipher.KeyPair sharedKeys;
+
+    @BeforeAll
+    static void setup() {
+        // Generate 256-bit keys for efficient unit testing
+        sharedKeys = ElGamalCipher.generateKeys(256);
+    }
+
+    @Test
+    @DisplayName("Test Key Generation Validity")
+    void testKeyGeneration() {
+        Assertions.assertNotNull(sharedKeys.p());
+        Assertions.assertNotNull(sharedKeys.g());
+        Assertions.assertNotNull(sharedKeys.x());
+        Assertions.assertNotNull(sharedKeys.y());
+
+        // Verify generator bounds: 1 < g < p
+        Assertions.assertTrue(sharedKeys.g().compareTo(BigInteger.ONE) > 0);
+        Assertions.assertTrue(sharedKeys.g().compareTo(sharedKeys.p()) < 0);
+
+        // Verify private key bounds: 1 < x < p-1
+        Assertions.assertTrue(sharedKeys.x().compareTo(BigInteger.ONE) > 0);
+        Assertions.assertTrue(sharedKeys.x().compareTo(sharedKeys.p().subtract(BigInteger.ONE)) < 0);
+    }
+
+    @Test
+    @DisplayName("Security Check: Probabilistic Encryption")
+    void testSemanticSecurity() {
+        // Encrypting the same message twice MUST yield different ciphertexts
+        // due to the random ephemeral key 'k'.
+        BigInteger message = new BigInteger("123456789");
+
+        ElGamalCipher.CipherText c1 = ElGamalCipher.encrypt(message, sharedKeys.p(), sharedKeys.g(), sharedKeys.y());
+        ElGamalCipher.CipherText c2 = ElGamalCipher.encrypt(message, sharedKeys.p(), sharedKeys.g(), sharedKeys.y());
+
+        // Check that the ephemeral keys (and thus 'a' components) were different
+        Assertions.assertNotEquals(c1.a(), c2.a(), "Ciphertexts must be randomized (Semantic Security violation)");
+        Assertions.assertNotEquals(c1.b(), c2.b());
+
+        // But both must decrypt to the original message
+        Assertions.assertEquals(ElGamalCipher.decrypt(c1, sharedKeys.x(), sharedKeys.p()), message);
+        Assertions.assertEquals(ElGamalCipher.decrypt(c2, sharedKeys.x(), sharedKeys.p()), message);
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideMessages")
+    @DisplayName("Parameterized Test: Encrypt and Decrypt various messages")
+    void testEncryptDecrypt(String messageStr) {
+        BigInteger message = new BigInteger(messageStr.getBytes());
+
+        // Skip if message exceeds the test key size (256 bits)
+        if (message.compareTo(sharedKeys.p()) >= 0) {
+            return;
+        }
+
+        ElGamalCipher.CipherText ciphertext = ElGamalCipher.encrypt(message, sharedKeys.p(), sharedKeys.g(), sharedKeys.y());
+        BigInteger decrypted = ElGamalCipher.decrypt(ciphertext, sharedKeys.x(), sharedKeys.p());
+
+        Assertions.assertEquals(message, decrypted, "Decrypted BigInteger must match original");
+        Assertions.assertEquals(messageStr, new String(decrypted.toByteArray()), "Decrypted string must match original");
+    }
+
+    static Stream<String> provideMessages() {
+        return Stream.of("Hello World", "TheAlgorithms", "A", "1234567890", "!@#$%^&*()");
+    }
+
+    @Test
+    @DisplayName("Edge Case: Message equals 0")
+    void testMessageZero() {
+        BigInteger zero = BigInteger.ZERO;
+        ElGamalCipher.CipherText ciphertext = ElGamalCipher.encrypt(zero, sharedKeys.p(), sharedKeys.g(), sharedKeys.y());
+        BigInteger decrypted = ElGamalCipher.decrypt(ciphertext, sharedKeys.x(), sharedKeys.p());
+
+        Assertions.assertEquals(zero, decrypted, "Should successfully encrypt/decrypt zero");
+    }
+
+    @Test
+    @DisplayName("Edge Case: Message equals p-1")
+    void testMessageMaxBound() {
+        BigInteger pMinus1 = sharedKeys.p().subtract(BigInteger.ONE);
+        ElGamalCipher.CipherText ciphertext = ElGamalCipher.encrypt(pMinus1, sharedKeys.p(), sharedKeys.g(), sharedKeys.y());
+        BigInteger decrypted = ElGamalCipher.decrypt(ciphertext, sharedKeys.x(), sharedKeys.p());
+
+        Assertions.assertEquals(pMinus1, decrypted, "Should successfully encrypt/decrypt p-1");
+    }
+
+    @Test
+    @DisplayName("Negative Test: Message >= p should fail")
+    void testMessageTooLarge() {
+        BigInteger tooLarge = sharedKeys.p();
+        Assertions.assertThrows(IllegalArgumentException.class, () -> ElGamalCipher.encrypt(tooLarge, sharedKeys.p(), sharedKeys.g(), sharedKeys.y()));
+    }
+
+    @Test
+    @DisplayName("Negative Test: Decrypt with wrong private key")
+    void testWrongKeyDecryption() {
+        BigInteger message = new BigInteger("99999");
+        ElGamalCipher.CipherText ciphertext = ElGamalCipher.encrypt(message, sharedKeys.p(), sharedKeys.g(), sharedKeys.y());
+
+        // Generate a fake private key
+        BigInteger wrongX = sharedKeys.x().add(BigInteger.ONE);
+
+        BigInteger decrypted = ElGamalCipher.decrypt(ciphertext, wrongX, sharedKeys.p());
+
+        Assertions.assertNotEquals(message, decrypted, "Decryption with wrong key must yield incorrect result");
+    }
+
+    @Test
+    @DisplayName("Property Test: Multiplicative Homomorphism")
+    void testHomomorphism() {
+        BigInteger m1 = new BigInteger("50");
+        BigInteger m2 = BigInteger.TEN; // Fix: Replaced new BigInteger("10") with BigInteger.TEN
+
+        ElGamalCipher.CipherText c1 = ElGamalCipher.encrypt(m1, sharedKeys.p(), sharedKeys.g(), sharedKeys.y());
+        ElGamalCipher.CipherText c2 = ElGamalCipher.encrypt(m2, sharedKeys.p(), sharedKeys.g(), sharedKeys.y());
+
+        // Multiply ciphertexts component-wise: (a1*a2, b1*b2)
+        BigInteger aNew = c1.a().multiply(c2.a()).mod(sharedKeys.p());
+        BigInteger bNew = c1.b().multiply(c2.b()).mod(sharedKeys.p());
+        ElGamalCipher.CipherText cCombined = new ElGamalCipher.CipherText(aNew, bNew);
+
+        BigInteger decrypted = ElGamalCipher.decrypt(cCombined, sharedKeys.x(), sharedKeys.p());
+        BigInteger expected = m1.multiply(m2).mod(sharedKeys.p());
+
+        Assertions.assertEquals(expected, decrypted, "Cipher must satisfy multiplicative homomorphism");
+    }
+}

From 249b88fea2d8e7d425af8db053196e9b2cf1ed2c Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 5 Feb 2026 23:03:26 +0100
Subject: [PATCH 1185/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.1.0 to 13.2.0 (#7259)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.1.0 to 13.2.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.1.0...checkstyle-13.2.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.2.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index f13169cece97..3716323bd115 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.1.0</version>
+                    <version>13.2.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 3835c4822a651f90be03830f778bbc41c898c64c Mon Sep 17 00:00:00 2001
From: swativ15 <122958079+swativ15@users.noreply.github.com>
Date: Fri, 6 Feb 2026 03:37:11 +0530
Subject: [PATCH 1186/1338] Refactor: simplify validation and improve
 backtracking cleanup (#7258)

### Summary
This PR makes small readability and maintainability improvements to the algorithm implementation.

### Changes
- Removed a redundant `n < 0` validation check since the method contract already ensures valid `n`
- Replaced `current.remove(current.size() - 1)` with `current.removeLast()` to better express backtracking intent

### Rationale
- Simplifies input validation without changing behavior
- Uses the `Deque` API to make the backtracking step clearer and less error-prone

### Impact
- No change in algorithm logic or time/space complexity
- Output remains identical

Co-authored-by: Swati Vusurumarthi <swativs869@gmail.com>
---
 .../com/thealgorithms/backtracking/ArrayCombination.java    | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
index f8cd0c40c20e..d05e33a4242f 100644
--- a/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
+++ b/src/main/java/com/thealgorithms/backtracking/ArrayCombination.java
@@ -20,8 +20,8 @@ private ArrayCombination() {
      * @throws IllegalArgumentException if n or k are negative, or if k is greater than n.
      */
     public static List<List<Integer>> combination(int n, int k) {
-        if (n < 0 || k < 0 || k > n) {
-            throw new IllegalArgumentException("Invalid input: n must be non-negative, k must be non-negative and less than or equal to n.");
+        if (k < 0 || k > n) {
+            throw new IllegalArgumentException("Invalid input: 0 ≤ k ≤ n is required.");
         }
 
         List<List<Integer>> combinations = new ArrayList<>();
@@ -48,7 +48,7 @@ private static void combine(List<List<Integer>> combinations, List<Integer> curr
         for (int i = start; i < n; i++) {
             current.add(i);
             combine(combinations, current, i + 1, n, k);
-            current.remove(current.size() - 1); // Backtrack
+            current.removeLast(); // Backtrack
         }
     }
 }

From 8403b8feb198ce250a1e2aef4416216154300961 Mon Sep 17 00:00:00 2001
From: Adarsh-Melath <adarshmelath1305@gmail.com>
Date: Mon, 9 Feb 2026 23:02:56 +0530
Subject: [PATCH 1187/1338] fix:shape's dimension constraints added correctyl 
 (issue id: #7260) (#7261)

* fix:shape's dimension constraints added correctyl  (issue id: #7260)

* fix: base changed to baseLength for better understanding

* fix: base changed to baseLength for better understanding

* base changed to baseLength for better understanding

* fix:cleared some format issues

* fix:cleared some format issues
---
 .../java/com/thealgorithms/maths/Area.java    | 38 +++++++++----------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Area.java b/src/main/java/com/thealgorithms/maths/Area.java
index 1eba6666dde3..08807580cb03 100644
--- a/src/main/java/com/thealgorithms/maths/Area.java
+++ b/src/main/java/com/thealgorithms/maths/Area.java
@@ -10,17 +10,17 @@ private Area() {
     /**
      * String of IllegalArgumentException for radius
      */
-    private static final String POSITIVE_RADIUS = "Must be a positive radius";
+    private static final String POSITIVE_RADIUS = "Radius must be greater than 0";
 
     /**
      * String of IllegalArgumentException for height
      */
-    private static final String POSITIVE_HEIGHT = "Must be a positive height";
+    private static final String POSITIVE_HEIGHT = "Height must be greater than 0";
 
     /**
      * String of IllegalArgumentException for base
      */
-    private static final String POSITIVE_BASE = "Must be a positive base";
+    private static final String POSITIVE_BASE = "Base must be greater than 0";
 
     /**
      * Calculate the surface area of a cube.
@@ -30,7 +30,7 @@ private Area() {
      */
     public static double surfaceAreaCube(final double sideLength) {
         if (sideLength <= 0) {
-            throw new IllegalArgumentException("Must be a positive sideLength");
+            throw new IllegalArgumentException("Side length must be greater than 0");
         }
         return 6 * sideLength * sideLength;
     }
@@ -57,10 +57,10 @@ public static double surfaceAreaSphere(final double radius) {
      */
     public static double surfaceAreaPyramid(final double sideLength, final double slantHeight) {
         if (sideLength <= 0) {
-            throw new IllegalArgumentException("Must be a positive sideLength");
+            throw new IllegalArgumentException("");
         }
         if (slantHeight <= 0) {
-            throw new IllegalArgumentException("Must be a positive slantHeight");
+            throw new IllegalArgumentException("slant height must be greater than 0");
         }
         double baseArea = sideLength * sideLength;
         double lateralSurfaceArea = 2 * sideLength * slantHeight;
@@ -76,10 +76,10 @@ public static double surfaceAreaPyramid(final double sideLength, final double sl
      */
     public static double surfaceAreaRectangle(final double length, final double width) {
         if (length <= 0) {
-            throw new IllegalArgumentException("Must be a positive length");
+            throw new IllegalArgumentException("Length must be greater than 0");
         }
         if (width <= 0) {
-            throw new IllegalArgumentException("Must be a positive width");
+            throw new IllegalArgumentException("Width must be greater than 0");
         }
         return length * width;
     }
@@ -109,7 +109,7 @@ public static double surfaceAreaCylinder(final double radius, final double heigh
      */
     public static double surfaceAreaSquare(final double sideLength) {
         if (sideLength <= 0) {
-            throw new IllegalArgumentException("Must be a positive sideLength");
+            throw new IllegalArgumentException("Side Length must be greater than 0");
         }
         return sideLength * sideLength;
     }
@@ -121,14 +121,14 @@ public static double surfaceAreaSquare(final double sideLength) {
      * @param height height of triangle
      * @return area of given triangle
      */
-    public static double surfaceAreaTriangle(final double base, final double height) {
-        if (base <= 0) {
+    public static double surfaceAreaTriangle(final double baseLength, final double height) {
+        if (baseLength <= 0) {
             throw new IllegalArgumentException(POSITIVE_BASE);
         }
         if (height <= 0) {
             throw new IllegalArgumentException(POSITIVE_HEIGHT);
         }
-        return base * height / 2;
+        return baseLength * height / 2;
     }
 
     /**
@@ -138,14 +138,14 @@ public static double surfaceAreaTriangle(final double base, final double height)
      * @param height height of a parallelogram
      * @return area of given parallelogram
      */
-    public static double surfaceAreaParallelogram(final double base, final double height) {
-        if (base <= 0) {
+    public static double surfaceAreaParallelogram(final double baseLength, final double height) {
+        if (baseLength <= 0) {
             throw new IllegalArgumentException(POSITIVE_BASE);
         }
         if (height <= 0) {
             throw new IllegalArgumentException(POSITIVE_HEIGHT);
         }
-        return base * height;
+        return baseLength * height;
     }
 
     /**
@@ -156,17 +156,17 @@ public static double surfaceAreaParallelogram(final double base, final double he
      * @param height height of trapezium
      * @return area of given trapezium
      */
-    public static double surfaceAreaTrapezium(final double base1, final double base2, final double height) {
-        if (base1 <= 0) {
+    public static double surfaceAreaTrapezium(final double baseLength1, final double baseLength2, final double height) {
+        if (baseLength1 <= 0) {
             throw new IllegalArgumentException(POSITIVE_BASE + 1);
         }
-        if (base2 <= 0) {
+        if (baseLength2 <= 0) {
             throw new IllegalArgumentException(POSITIVE_BASE + 2);
         }
         if (height <= 0) {
             throw new IllegalArgumentException(POSITIVE_HEIGHT);
         }
-        return (base1 + base2) * height / 2;
+        return (baseLength1 + baseLength2) * height / 2;
     }
 
     /**

From 0c79d33eb591842c8cc809f02a9303ab843a1c37 Mon Sep 17 00:00:00 2001
From: Mohammed Vijahath <116938255+vizahat36@users.noreply.github.com>
Date: Wed, 11 Feb 2026 20:30:15 +0530
Subject: [PATCH 1188/1338] Add Tower of Hanoi recursive algorithm (#7235)

* Add Tower of Hanoi recursive algorithm with tests

* Fix SpotBugs issues and format TowerOfHanoi tests

* Enhance existing TowerOfHanoi and remove duplicate recursion version

* Fix clang-format issue

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../puzzlesandgames/TowerOfHanoi.java         | 51 +++++++++++--------
 .../puzzlesandgames/TowerOfHanoiTest.java     | 32 ++++++++++++
 2 files changed, 63 insertions(+), 20 deletions(-)

diff --git a/src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java b/src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java
index 72e9a14ac070..d94bef69cd3a 100644
--- a/src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java
+++ b/src/main/java/com/thealgorithms/puzzlesandgames/TowerOfHanoi.java
@@ -3,27 +3,32 @@
 import java.util.List;
 
 /**
- * The {@code TowerOfHanoi} class provides a recursive solution to the Tower of Hanoi puzzle.
- * This puzzle involves moving a set of discs from one pole to another, following specific rules:
+ * Recursive solution to the Tower of Hanoi puzzle.
+ *
+ * <p>
+ * The puzzle rules are:
  * 1. Only one disc can be moved at a time.
  * 2. A disc can only be placed on top of a larger disc.
  * 3. All discs must start on one pole and end on another.
+ * </p>
  *
- * This implementation recursively calculates the steps required to solve the puzzle and stores them
- * in a provided list.
+ * <p>
+ * The recursion follows three steps:
+ * 1. Move {@code n-1} discs from start to intermediate.
+ * 2. Move the largest disc from start to end.
+ * 3. Move {@code n-1} discs from intermediate to end.
+ * </p>
  *
  * <p>
- * For more information about the Tower of Hanoi, see
- * <a href="https://en.wikipedia.org/wiki/Tower_of_Hanoi">Tower of Hanoi on Wikipedia</a>.
+ * Time Complexity: O(2^n) - exponential due to recursive expansion.
+ * Space Complexity: O(n) - recursion stack depth.
  * </p>
  *
- * The {@code shift} method takes the number of discs and the names of the poles,
- * and appends the steps required to solve the puzzle to the provided list.
- * Time Complexity: O(2^n) - Exponential time complexity due to the recursive nature of the problem.
- * Space Complexity: O(n) - Linear space complexity due to the recursion stack.
- * Wikipedia: https://en.wikipedia.org/wiki/Tower_of_Hanoi
+ * <p>
+ * See <a href="https://en.wikipedia.org/wiki/Tower_of_Hanoi">Tower of Hanoi on Wikipedia</a>.
+ * </p>
  */
-final class TowerOfHanoi {
+public final class TowerOfHanoi {
 
     private TowerOfHanoi() {
     }
@@ -36,6 +41,7 @@ private TowerOfHanoi() {
      * @param intermediatePole The name of the intermediate pole used as a temporary holding area.
      * @param endPole          The name of the end pole to which discs are moved.
      * @param result           A list to store the steps required to solve the puzzle.
+     * @throws IllegalArgumentException if {@code n} is negative.
      *
      *                         <p>
      *                         This method is called recursively to move n-1 discs
@@ -51,15 +57,20 @@ private TowerOfHanoi() {
      *                         </p>
      */
     public static void shift(int n, String startPole, String intermediatePole, String endPole, List<String> result) {
-        if (n != 0) {
-            // Move n-1 discs from startPole to intermediatePole
-            shift(n - 1, startPole, endPole, intermediatePole, result);
+        if (n < 0) {
+            throw new IllegalArgumentException("Number of discs must be non-negative");
+        }
+        if (n == 0) {
+            return;
+        }
 
-            // Add the move of the nth disc from startPole to endPole
-            result.add(String.format("Move %d from %s to %s", n, startPole, endPole));
+        // Move n-1 discs from startPole to intermediatePole
+        shift(n - 1, startPole, endPole, intermediatePole, result);
 
-            // Move the n-1 discs from intermediatePole to endPole
-            shift(n - 1, intermediatePole, startPole, endPole, result);
-        }
+        // Add the move of the nth disc from startPole to endPole
+        result.add(String.format("Move %d from %s to %s", n, startPole, endPole));
+
+        // Move the n-1 discs from intermediatePole to endPole
+        shift(n - 1, intermediatePole, startPole, endPole, result);
     }
 }
diff --git a/src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java b/src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java
index 42669eb03bb4..f0a2686d3e4b 100644
--- a/src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java
+++ b/src/test/java/com/thealgorithms/puzzlesandgames/TowerOfHanoiTest.java
@@ -1,14 +1,31 @@
 package com.thealgorithms.puzzlesandgames;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class TowerOfHanoiTest {
 
+    @ParameterizedTest
+    @MethodSource("diskCountAndMoveCount")
+    void testMoveCountMatchesFormula(int disks, int expectedMoves) {
+        List<String> result = new ArrayList<>();
+        TowerOfHanoi.shift(disks, "A", "B", "C", result);
+        assertEquals(expectedMoves, result.size());
+    }
+
+    private static Stream<Arguments> diskCountAndMoveCount() {
+        return Stream.of(Arguments.of(1, 1), Arguments.of(2, 3), Arguments.of(3, 7), Arguments.of(4, 15), Arguments.of(5, 31), Arguments.of(10, 1023));
+    }
+
     @Test
     public void testHanoiWithOneDisc() {
         List<String> result = new ArrayList<>();
@@ -39,6 +56,15 @@ public void testHanoiWithThreeDiscs() {
         assertEquals(expected, result);
     }
 
+    @Test
+    public void testHanoiWithDifferentPoles() {
+        List<String> result = new ArrayList<>();
+        TowerOfHanoi.shift(2, "X", "Y", "Z", result);
+
+        List<String> expected = List.of("Move 1 from X to Y", "Move 2 from X to Z", "Move 1 from Y to Z");
+        assertEquals(expected, result);
+    }
+
     @Test
     public void testHanoiWithZeroDiscs() {
         List<String> result = new ArrayList<>();
@@ -47,4 +73,10 @@ public void testHanoiWithZeroDiscs() {
         // There should be no moves if there are 0 discs
         assertTrue(result.isEmpty());
     }
+
+    @Test
+    public void testHanoiWithNegativeDiscsThrows() {
+        List<String> result = new ArrayList<>();
+        assertThrows(IllegalArgumentException.class, () -> TowerOfHanoi.shift(-1, "Pole1", "Pole2", "Pole3", result));
+    }
 }

From 504b5283eb75f9416693740eba48c5cea9eb28bd Mon Sep 17 00:00:00 2001
From: Muhammad Muneeb Mubashar <muhammadmuneebmubashar@gmail.com>
Date: Fri, 13 Feb 2026 01:43:27 -0800
Subject: [PATCH 1189/1338] Refactor getAbsValue method to use Math.abs (#7266)

---
 src/main/java/com/thealgorithms/maths/AbsoluteValue.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/maths/AbsoluteValue.java b/src/main/java/com/thealgorithms/maths/AbsoluteValue.java
index b9279d5a244a..114eb71b1015 100644
--- a/src/main/java/com/thealgorithms/maths/AbsoluteValue.java
+++ b/src/main/java/com/thealgorithms/maths/AbsoluteValue.java
@@ -11,6 +11,6 @@ private AbsoluteValue() {
      * @return The absolute value of the {@code number}
      */
     public static int getAbsValue(int number) {
-        return number < 0 ? -number : number;
+        return Math.abs(number);
     }
 }

From c8d029107ce397c6d427a23a5127003d87fb0792 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 16 Feb 2026 16:57:18 +0100
Subject: [PATCH 1190/1338] chore(deps): bump org.junit:junit-bom from 6.0.2 to
 6.0.3 (#7271)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 6.0.2 to 6.0.3.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r6.0.2...r6.0.3)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 6.0.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 3716323bd115..2445a1e920a8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>6.0.2</version>
+                <version>6.0.3</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From dfa6bf06910b2c989a0e4acb82155ebf51d869f9 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Tue, 17 Feb 2026 22:20:34 +0100
Subject: [PATCH 1191/1338] style: remove redundant PMD exclusions (#7272)

---
 pmd-exclude.properties | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index a3c95b12fa4b..64562c524728 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -53,14 +53,11 @@ com.thealgorithms.maths.Gaussian=UselessParentheses
 com.thealgorithms.maths.GcdSolutionWrapper=UselessParentheses
 com.thealgorithms.maths.HeronsFormula=UselessParentheses
 com.thealgorithms.maths.JugglerSequence=UselessMainMethod
-com.thealgorithms.maths.KaprekarNumbers=UselessParentheses
 com.thealgorithms.maths.KeithNumber=UselessMainMethod,UselessParentheses
-com.thealgorithms.maths.LeonardoNumber=UselessParentheses
 com.thealgorithms.maths.LinearDiophantineEquationsSolver=UselessMainMethod,UselessParentheses
 com.thealgorithms.maths.MagicSquare=UselessMainMethod
 com.thealgorithms.maths.PiNilakantha=UselessMainMethod
 com.thealgorithms.maths.Prime.PrimeCheck=UselessMainMethod
-com.thealgorithms.maths.PythagoreanTriple=UselessMainMethod
 com.thealgorithms.maths.RomanNumeralUtil=UselessParentheses
 com.thealgorithms.maths.SecondMinMax=UselessParentheses
 com.thealgorithms.maths.SecondMinMaxTest=UnnecessaryFullyQualifiedName
@@ -71,7 +68,6 @@ com.thealgorithms.maths.TrinomialTriangle=UselessMainMethod,UselessParentheses
 com.thealgorithms.maths.VectorCrossProduct=UselessMainMethod
 com.thealgorithms.maths.Volume=UselessParentheses
 com.thealgorithms.matrix.RotateMatrixBy90Degrees=UselessMainMethod
-com.thealgorithms.misc.Sparsity=UselessParentheses
 com.thealgorithms.others.BankersAlgorithm=UselessMainMethod
 com.thealgorithms.others.BrianKernighanAlgorithm=UselessMainMethod
 com.thealgorithms.others.CRC16=UselessMainMethod,UselessParentheses
@@ -79,11 +75,9 @@ com.thealgorithms.others.CRC32=UselessMainMethod
 com.thealgorithms.others.Damm=UnnecessaryFullyQualifiedName,UselessMainMethod
 com.thealgorithms.others.Dijkstra=UselessMainMethod
 com.thealgorithms.others.GaussLegendre=UselessMainMethod
-com.thealgorithms.others.HappyNumbersSeq=UselessMainMethod
 com.thealgorithms.others.Huffman=UselessMainMethod
 com.thealgorithms.others.InsertDeleteInArray=UselessMainMethod
 com.thealgorithms.others.KochSnowflake=UselessMainMethod
-com.thealgorithms.others.Krishnamurthy=UselessMainMethod
 com.thealgorithms.others.LinearCongruentialGenerator=UselessMainMethod
 com.thealgorithms.others.Luhn=UnnecessaryFullyQualifiedName,UselessMainMethod
 com.thealgorithms.others.Mandelbrot=UselessMainMethod,UselessParentheses
@@ -94,7 +88,6 @@ com.thealgorithms.others.PerlinNoise=UselessMainMethod,UselessParentheses
 com.thealgorithms.others.QueueUsingTwoStacks=UselessParentheses
 com.thealgorithms.others.Trieac=UselessMainMethod,UselessParentheses
 com.thealgorithms.others.Verhoeff=UnnecessaryFullyQualifiedName,UselessMainMethod
-com.thealgorithms.puzzlesandgames.Sudoku=UselessMainMethod
 com.thealgorithms.recursion.DiceThrower=UselessMainMethod
 com.thealgorithms.searches.HowManyTimesRotated=UselessMainMethod
 com.thealgorithms.searches.InterpolationSearch=UselessParentheses
@@ -108,15 +101,11 @@ com.thealgorithms.sorts.MergeSortNoExtraSpace=UselessParentheses
 com.thealgorithms.sorts.RadixSort=UselessParentheses
 com.thealgorithms.sorts.TreeSort=UselessMainMethod
 com.thealgorithms.sorts.WiggleSort=UselessParentheses
-com.thealgorithms.stacks.LargestRectangle=UselessMainMethod
 com.thealgorithms.stacks.MaximumMinimumWindow=UselessMainMethod
 com.thealgorithms.stacks.PostfixToInfix=UselessParentheses
-com.thealgorithms.strings.Alphabetical=UselessMainMethod
 com.thealgorithms.strings.HorspoolSearch=UnnecessaryFullyQualifiedName,UselessParentheses
-com.thealgorithms.strings.KMP=UselessMainMethod
 com.thealgorithms.strings.Lower=UselessMainMethod
 com.thealgorithms.strings.Palindrome=UselessParentheses
 com.thealgorithms.strings.Pangram=UselessMainMethod
-com.thealgorithms.strings.RabinKarp=UselessMainMethod
 com.thealgorithms.strings.Rotation=UselessMainMethod
 com.thealgorithms.strings.Upper=UselessMainMethod

From 1646edaeb96a27add8d83788782550ee2048b263 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 18 Feb 2026 18:06:08 +0100
Subject: [PATCH 1192/1338] style: remove redundant exclusions (#7276)

---
 spotbugs-exclude.xml | 39 ---------------------------------------
 1 file changed, 39 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 1390387bacdf..7483d37daa57 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -8,18 +8,12 @@
     <Match>
         <Bug pattern="DMI_RANDOM_USED_ONLY_ONCE" />
     </Match>
-    <Match>
-        <Bug pattern="SF_SWITCH_NO_DEFAULT" />
-    </Match>
     <Match>
         <Bug pattern="RV_RETURN_VALUE_IGNORED_NO_SIDE_EFFECT" />
     </Match>
     <Match>
         <Bug pattern="DM_NEXTINT_VIA_NEXTDOUBLE" />
     </Match>
-    <Match>
-        <Bug pattern="SIC_INNER_SHOULD_BE_STATIC" />
-    </Match>
     <Match>
         <Bug pattern="EI_EXPOSE_REP" />
     </Match>
@@ -32,15 +26,9 @@
     <Match>
         <Bug pattern="PA_PUBLIC_PRIMITIVE_ATTRIBUTE" />
     </Match>
-    <Match>
-        <Bug pattern="MS_PKGPROTECT" />
-    </Match>
     <Match>
         <Bug pattern="SE_COMPARATOR_SHOULD_BE_SERIALIZABLE" />
     </Match>
-    <Match>
-        <Bug pattern="INT_BAD_REM_BY_1" />
-    </Match>
     <Match>
         <Bug pattern="FE_FLOATING_POINT_EQUALITY" />
     </Match>
@@ -50,15 +38,9 @@
     <Match>
         <Bug pattern="URF_UNREAD_FIELD" />
     </Match>
-    <Match>
-        <Bug pattern="RC_REF_COMPARISON" />
-    </Match>
     <Match>
         <Bug pattern="MS_EXPOSE_REP" />
     </Match>
-    <Match>
-        <Bug pattern="DM_BOXED_PRIMITIVE_FOR_PARSING" />
-    </Match>
     <Match>
         <Bug pattern="UWF_UNWRITTEN_FIELD" />
     </Match>
@@ -71,9 +53,6 @@
     <Match>
         <Bug pattern="URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD" />
     </Match>
-    <Match>
-        <Bug pattern="NP_IMMEDIATE_DEREFERENCE_OF_READLINE" />
-    </Match>
     <Match>
         <Bug pattern="EQ_COMPARETO_USE_OBJECT_EQUALS" />
     </Match>
@@ -83,9 +62,6 @@
     <Match>
         <Bug pattern="AT_STALE_THREAD_WRITE_OF_PRIMITIVE" />
     </Match>
-    <Match>
-        <Bug pattern="SF_SWITCH_FALLTHROUGH" />
-    </Match>
     <!-- fb-contrib -->
     <Match>
         <Bug pattern="LSC_LITERAL_STRING_COMPARISON" />
@@ -117,9 +93,6 @@
     <Match>
         <Bug pattern="BL_BURYING_LOGIC" />
     </Match>
-    <Match>
-        <Bug pattern="UTWR_USE_TRY_WITH_RESOURCES" />
-    </Match>
     <Match>
         <Bug pattern="MUI_CONTAINSKEY_BEFORE_GET" />
     </Match>
@@ -150,9 +123,6 @@
     <Match>
         <Bug pattern="LSYC_LOCAL_SYNCHRONIZED_COLLECTION" />
     </Match>
-    <Match>
-        <Bug pattern="IOI_USE_OF_FILE_STREAM_CONSTRUCTORS" />
-    </Match>
     <Match>
         <Bug pattern="UP_UNUSED_PARAMETER" />
     </Match>
@@ -189,24 +159,15 @@
     <Match>
         <Bug pattern="STT_STRING_PARSING_A_FIELD" />
     </Match>
-    <Match>
-        <Bug pattern="IMC_IMMATURE_CLASS_BAD_SERIALVERSIONUID" />
-    </Match>
     <Match>
         <Bug pattern="DRE_DECLARED_RUNTIME_EXCEPTION" />
     </Match>
-    <Match>
-        <Bug pattern="BAS_BLOATED_ASSIGNMENT_SCOPE" />
-    </Match>
     <Match>
         <Bug pattern="SPP_FIELD_COULD_BE_STATIC" />
     </Match>
     <Match>
         <Bug pattern="ITC_INHERITANCE_TYPE_CHECKING" />
     </Match>
-    <Match>
-        <Bug pattern="FII_USE_ARRAYS_STREAM" />
-    </Match>
     <Match>
         <Bug pattern="UTAO_JUNIT_ASSERTION_ODDITIES_USE_ASSERT_EQUALS" />
     </Match>

From c9bda3dad761c5b27edc36e32b8b9c746ebda345 Mon Sep 17 00:00:00 2001
From: Syed Mohammad Saad <134770714+SYEDMDSAAD@users.noreply.github.com>
Date: Wed, 18 Feb 2026 23:54:34 +0530
Subject: [PATCH 1193/1338] Add string algorithms: RemoveStars and
 ComplexNumberMultiply (#7275)

* Add RemoveStars and ComplexNumberMultiply string algorithms

* Add RemoveStars and ComplexNumberMultiply string algorithms

* Add unit tests for RemoveStars and ComplexNumber Multiply

* Fix checkstyle

* Remove redundant main method

* Move ComplexNumberMultiply to maths package and add input validation with tests

* Apply spotless formatting

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../maths/ComplexNumberMultiply.java          | 32 +++++++++++++++++
 .../thealgorithms/strings/RemoveStars.java    | 31 +++++++++++++++++
 .../maths/ComplexNumberMultiplyTest.java      | 34 +++++++++++++++++++
 .../strings/RemoveStarsTest.java              | 28 +++++++++++++++
 4 files changed, 125 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/ComplexNumberMultiply.java
 create mode 100644 src/main/java/com/thealgorithms/strings/RemoveStars.java
 create mode 100644 src/test/java/com/thealgorithms/maths/ComplexNumberMultiplyTest.java
 create mode 100644 src/test/java/com/thealgorithms/strings/RemoveStarsTest.java

diff --git a/src/main/java/com/thealgorithms/maths/ComplexNumberMultiply.java b/src/main/java/com/thealgorithms/maths/ComplexNumberMultiply.java
new file mode 100644
index 000000000000..4b68b7824574
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/ComplexNumberMultiply.java
@@ -0,0 +1,32 @@
+package com.thealgorithms.maths;
+
+/**
+ * Multiplies two complex numbers represented as strings in the form "a+bi".
+ * Supports negative values and validates input format.
+ */
+public final class ComplexNumberMultiply {
+
+    private ComplexNumberMultiply() {
+    }
+
+    private static int[] parse(String num) {
+        if (num == null || !num.matches("-?\\d+\\+-?\\d+i")) {
+            throw new IllegalArgumentException("Invalid complex number format: " + num);
+        }
+
+        String[] parts = num.split("\\+");
+        int real = Integer.parseInt(parts[0]);
+        int imaginary = Integer.parseInt(parts[1].replace("i", ""));
+        return new int[] {real, imaginary};
+    }
+
+    public static String multiply(String num1, String num2) {
+        int[] a = parse(num1);
+        int[] b = parse(num2);
+
+        int real = a[0] * b[0] - a[1] * b[1];
+        int imaginary = a[0] * b[1] + a[1] * b[0];
+
+        return real + "+" + imaginary + "i";
+    }
+}
diff --git a/src/main/java/com/thealgorithms/strings/RemoveStars.java b/src/main/java/com/thealgorithms/strings/RemoveStars.java
new file mode 100644
index 000000000000..816311e9da84
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/RemoveStars.java
@@ -0,0 +1,31 @@
+package com.thealgorithms.strings;
+
+/**
+ * Removes characters affected by '*' in a string.
+ * Each '*' deletes the closest non-star character to its left.
+ *
+ * Example:
+ * Input: leet**cod*e
+ * Output: lecoe
+ */
+
+public final class RemoveStars {
+
+    private RemoveStars() {
+    }
+
+    public static String removeStars(String s) {
+        StringBuilder result = new StringBuilder();
+
+        for (char c : s.toCharArray()) {
+            if (c == '*') {
+                if (result.length() > 0) {
+                    result.deleteCharAt(result.length() - 1);
+                }
+            } else {
+                result.append(c);
+            }
+        }
+        return result.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/ComplexNumberMultiplyTest.java b/src/test/java/com/thealgorithms/maths/ComplexNumberMultiplyTest.java
new file mode 100644
index 000000000000..02e964b53771
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/ComplexNumberMultiplyTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class ComplexNumberMultiplyTest {
+
+    @Test
+    void testExample() {
+        assertEquals("0+2i", ComplexNumberMultiply.multiply("1+1i", "1+1i"));
+    }
+
+    @Test
+    void testNegative() {
+        assertEquals("0+-2i", ComplexNumberMultiply.multiply("1+-1i", "1+-1i"));
+    }
+
+    @Test
+    void testZero() {
+        assertEquals("0+0i", ComplexNumberMultiply.multiply("0+0i", "5+3i"));
+    }
+
+    @Test
+    void testInvalidFormat() {
+        assertThrows(IllegalArgumentException.class, () -> ComplexNumberMultiply.multiply("1+1", "1+1i"));
+    }
+
+    @Test
+    void testNullInput() {
+        assertThrows(IllegalArgumentException.class, () -> ComplexNumberMultiply.multiply(null, "1+1i"));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/RemoveStarsTest.java b/src/test/java/com/thealgorithms/strings/RemoveStarsTest.java
new file mode 100644
index 000000000000..3beb2e83399b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/RemoveStarsTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class RemoveStarsTest {
+
+    @Test
+    void testExampleCase() {
+        assertEquals("lecoe", RemoveStars.removeStars("leet**cod*e"));
+    }
+
+    @Test
+    void testAllStars() {
+        assertEquals("", RemoveStars.removeStars("abc***"));
+    }
+
+    @Test
+    void testNoStars() {
+        assertEquals("hello", RemoveStars.removeStars("hello"));
+    }
+
+    @Test
+    void testSingleCharacter() {
+        assertEquals("", RemoveStars.removeStars("a*"));
+    }
+}

From 2ae1bdfd9a3897d206c0e62751b7ec562dcafb08 Mon Sep 17 00:00:00 2001
From: Neha-2005-VCE <nehagoud300@gmail.com>
Date: Thu, 19 Feb 2026 00:04:41 +0530
Subject: [PATCH 1194/1338] feat: add contains() method to DynamicArray (#7270)

* feat: add contains() method to DynamicArray

* style: fix clang formatting

* style: fix clang format issues

* style: apply remaining clang formatting

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../dynamicarray/DynamicArray.java            | 43 +++++++++++++++----
 .../dynamicarray/DynamicArrayTest.java        | 19 ++++++++
 2 files changed, 53 insertions(+), 9 deletions(-)

diff --git a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
index cd5dc580b694..dbdb2d806209 100644
--- a/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
+++ b/src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java
@@ -63,7 +63,8 @@ public void add(final E element) {
      *
      * @param index   the index at which the element is to be placed
      * @param element the element to be inserted at the specified index
-     * @throws IndexOutOfBoundsException if index is less than 0 or greater than or equal to the number of elements
+     * @throws IndexOutOfBoundsException if index is less than 0 or greater than or
+     *                                   equal to the number of elements
      */
     public void put(final int index, E element) {
         if (index < 0) {
@@ -82,7 +83,8 @@ public void put(final int index, E element) {
      *
      * @param index the index of the element to retrieve
      * @return the element at the specified index
-     * @throws IndexOutOfBoundsException if index is less than 0 or greater than or equal to the current size
+     * @throws IndexOutOfBoundsException if index is less than 0 or greater than or
+     *                                   equal to the current size
      */
     @SuppressWarnings("unchecked")
     public E get(final int index) {
@@ -97,7 +99,8 @@ public E get(final int index) {
      *
      * @param index the index of the element to be removed
      * @return the element that was removed from the array
-     * @throws IndexOutOfBoundsException if index is less than 0 or greater than or equal to the current size
+     * @throws IndexOutOfBoundsException if index is less than 0 or greater than or
+     *                                   equal to the current size
      */
     public E remove(final int index) {
         if (index < 0 || index >= size) {
@@ -127,6 +130,21 @@ public boolean isEmpty() {
         return size == 0;
     }
 
+    /**
+     * Checks whether the array contains the specified element.
+     *
+     * @param element the element to check for
+     * @return true if the array contains the specified element, false otherwise
+     */
+    public boolean contains(final E element) {
+        for (int i = 0; i < size; i++) {
+            if (Objects.equals(elements[i], element)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * Returns a sequential stream with this collection as its source.
      *
@@ -137,7 +155,8 @@ public Stream<E> stream() {
     }
 
     /**
-     * Ensures that the array has enough capacity to hold the specified number of elements.
+     * Ensures that the array has enough capacity to hold the specified number of
+     * elements.
      *
      * @param minCapacity the minimum capacity required
      */
@@ -150,7 +169,8 @@ private void ensureCapacity(int minCapacity) {
 
     /**
      * Removes the element at the specified index without resizing the array.
-     * This method shifts any subsequent elements to the left and clears the last element.
+     * This method shifts any subsequent elements to the left and clears the last
+     * element.
      *
      * @param index the index of the element to remove
      */
@@ -163,7 +183,8 @@ private void fastRemove(int index) {
     }
 
     /**
-     * Returns a string representation of the array, including only the elements that are currently stored.
+     * Returns a string representation of the array, including only the elements
+     * that are currently stored.
      *
      * @return a string containing the elements in the array
      */
@@ -227,7 +248,9 @@ public E next() {
         /**
          * Removes the last element returned by this iterator.
          *
-         * @throws IllegalStateException if the next method has not yet been called, or the remove method has already been called after the last call to the next method
+         * @throws IllegalStateException if the next method has not yet been called, or
+         *                               the remove method has already been called after
+         *                               the last call to the next method
          */
         @Override
         public void remove() {
@@ -242,7 +265,8 @@ public void remove() {
         /**
          * Checks for concurrent modifications to the array during iteration.
          *
-         * @throws ConcurrentModificationException if the array has been modified structurally
+         * @throws ConcurrentModificationException if the array has been modified
+         *                                         structurally
          */
         private void checkForComodification() {
             if (modCount != expectedModCount) {
@@ -251,7 +275,8 @@ private void checkForComodification() {
         }
 
         /**
-         * Performs the given action for each remaining element in the iterator until all elements have been processed.
+         * Performs the given action for each remaining element in the iterator until
+         * all elements have been processed.
          *
          * @param action the action to be performed for each element
          * @throws NullPointerException if the specified action is null
diff --git a/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java b/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java
index 8fdc93e1ca22..39e3fa0abe77 100644
--- a/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java
@@ -255,4 +255,23 @@ public void testCapacityDoubling() {
         assertEquals(3, array.getSize());
         assertEquals("Charlie", array.get(2));
     }
+
+    @Test
+    public void testContains() {
+        DynamicArray<Integer> array = new DynamicArray<>();
+        array.add(1);
+        array.add(2);
+        array.add(3);
+
+        assertTrue(array.contains(2));
+        assertFalse(array.contains(5));
+    }
+
+    @Test
+    public void testContainsWithNull() {
+        DynamicArray<String> array = new DynamicArray<>();
+        array.add(null);
+
+        assertTrue(array.contains(null));
+    }
 }

From 0a2c7f2e3bb539d3aee68673b5d743d178d455b2 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Wed, 18 Feb 2026 20:32:32 +0100
Subject: [PATCH 1195/1338] style: include `BL_BURYING_LOGIC` (#7277)

---
 spotbugs-exclude.xml                          |  3 --
 .../searches/RecursiveBinarySearch.java       | 33 +++++++++----------
 2 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 7483d37daa57..a8eedcfed402 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -90,9 +90,6 @@
     <Match>
         <Bug pattern="USBR_UNNECESSARY_STORE_BEFORE_RETURN" />
     </Match>
-    <Match>
-        <Bug pattern="BL_BURYING_LOGIC" />
-    </Match>
     <Match>
         <Bug pattern="MUI_CONTAINSKEY_BEFORE_GET" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
index daf0c12c0978..1716e78964ae 100644
--- a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java
@@ -23,28 +23,27 @@ public int find(T[] arr, T target) {
 
     // Recursive binary search function
     public int binsear(T[] arr, int left, int right, T target) {
-        if (right >= left) {
-            int mid = left + (right - left) / 2;
-
-            // Compare the element at the middle with the target
-            int comparison = arr[mid].compareTo(target);
+        if (right < left) {
+            // Element is not present in the array
+            return -1;
+        }
+        final int mid = left + (right - left) / 2;
 
-            // If the element is equal to the target, return its index
-            if (comparison == 0) {
-                return mid;
-            }
+        // Compare the element at the middle with the target
+        final int comparison = arr[mid].compareTo(target);
 
-            // If the element is greater than the target, search in the left subarray
-            if (comparison > 0) {
-                return binsear(arr, left, mid - 1, target);
-            }
+        // If the element is equal to the target, return its index
+        if (comparison == 0) {
+            return mid;
+        }
 
-            // Otherwise, search in the right subarray
-            return binsear(arr, mid + 1, right, target);
+        // If the element is greater than the target, search in the left subarray
+        if (comparison > 0) {
+            return binsear(arr, left, mid - 1, target);
         }
 
-        // Element is not present in the array
-        return -1;
+        // Otherwise, search in the right subarray
+        return binsear(arr, mid + 1, right, target);
     }
 
     public static void main(String[] args) {

From 29ce2ef66607083e922b389650af160b7606903a Mon Sep 17 00:00:00 2001
From: Ruturaj Jadhav <ruturajjadhav122@gmail.com>
Date: Fri, 20 Feb 2026 02:41:56 +0530
Subject: [PATCH 1196/1338] Add RangeSumQuery algorithm in prefix folder
 (#7280)

* add Subarray Sum Equals K using prefix sum

* Add RangeSumQuery algorithm in prefix folder

* chore: apply clang-format to RangeSumQueryTest file

* Add import statement for JUnit test class

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../prefixsum/RangeSumQuery.java              | 73 +++++++++++++++++++
 .../prefixsum/RangeSumQueryTest.java          | 73 +++++++++++++++++++
 2 files changed, 146 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/prefixsum/RangeSumQuery.java
 create mode 100644 src/test/java/com/thealgorithms/prefixsum/RangeSumQueryTest.java

diff --git a/src/main/java/com/thealgorithms/prefixsum/RangeSumQuery.java b/src/main/java/com/thealgorithms/prefixsum/RangeSumQuery.java
new file mode 100644
index 000000000000..14a02a2de4d0
--- /dev/null
+++ b/src/main/java/com/thealgorithms/prefixsum/RangeSumQuery.java
@@ -0,0 +1,73 @@
+package com.thealgorithms.prefixsum;
+
+/**
+ * Implements an algorithm to efficiently compute the sum of elements
+ * between any two indices in an integer array using the Prefix Sum technique.
+ *
+ * <p>
+ * Given an array nums, this algorithm precomputes the prefix sum array
+ * to allow O(1) sum queries for any range [left, right].
+ * </p>
+ *
+ * <p>
+ * Let prefixSum[i] be the sum of elements from index 0 to i-1.
+ * The sum of elements from left to right is:
+ *
+ * <pre>
+ * prefixSum[right + 1] - prefixSum[left]
+ * </pre>
+ * </p>
+ *
+ * <p>
+ * <strong>Time Complexity:</strong> O(N) for preprocessing, O(1) per query<br>
+ * <strong>Space Complexity:</strong> O(N)
+ * </p>
+ *
+ * @author Ruturaj Jadhav, <a href="https://github.com/ruturajjadhav07">ruturajjadhav07</a>
+ */
+public final class RangeSumQuery {
+
+    private RangeSumQuery() {
+        // Utility class; prevent instantiation
+    }
+
+    /**
+     * Computes the prefix sum array for efficient range queries.
+     *
+     * @param nums The input integer array.
+     * @return Prefix sum array where prefixSum[i+1] = sum of nums[0..i].
+     * @throws IllegalArgumentException if nums is null.
+     */
+    public static int[] buildPrefixSum(int[] nums) {
+        if (nums == null) {
+            throw new IllegalArgumentException("Input array cannot be null");
+        }
+
+        int n = nums.length;
+        int[] prefixSum = new int[n + 1];
+        for (int i = 0; i < n; i++) {
+            prefixSum[i + 1] = prefixSum[i] + nums[i];
+        }
+        return prefixSum;
+    }
+
+    /**
+     * Returns the sum of elements from index left to right (inclusive)
+     * using the provided prefix sum array.
+     *
+     * @param prefixSum The prefix sum array computed using buildPrefixSum.
+     * @param left      The start index (inclusive).
+     * @param right     The end index (inclusive).
+     * @return The sum of elements in the range [left, right].
+     * @throws IllegalArgumentException if indices are invalid.
+     */
+    public static int sumRange(int[] prefixSum, int left, int right) {
+        if (prefixSum == null) {
+            throw new IllegalArgumentException("Prefix sum array cannot be null");
+        }
+        if (left < 0 || right >= prefixSum.length - 1 || left > right) {
+            throw new IllegalArgumentException("Invalid range indices");
+        }
+        return prefixSum[right + 1] - prefixSum[left];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/prefixsum/RangeSumQueryTest.java b/src/test/java/com/thealgorithms/prefixsum/RangeSumQueryTest.java
new file mode 100644
index 000000000000..12072318ac74
--- /dev/null
+++ b/src/test/java/com/thealgorithms/prefixsum/RangeSumQueryTest.java
@@ -0,0 +1,73 @@
+package com.thealgorithms.prefixsum;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests for {@link RangeSumQuery}.
+ */
+class RangeSumQueryTest {
+
+    @Test
+    void testBasicExample() {
+        int[] nums = {1, 2, 3, 4, 5};
+        int[] prefixSum = RangeSumQuery.buildPrefixSum(nums);
+
+        assertEquals(6, RangeSumQuery.sumRange(prefixSum, 0, 2)); // 1+2+3
+        assertEquals(9, RangeSumQuery.sumRange(prefixSum, 1, 3)); // 2+3+4
+        assertEquals(15, RangeSumQuery.sumRange(prefixSum, 0, 4)); // 1+2+3+4+5
+        assertEquals(12, RangeSumQuery.sumRange(prefixSum, 2, 4)); // 3+4+5
+    }
+
+    @Test
+    void testSingleElement() {
+        int[] nums = {7};
+        int[] prefixSum = RangeSumQuery.buildPrefixSum(nums);
+
+        assertEquals(7, RangeSumQuery.sumRange(prefixSum, 0, 0));
+    }
+
+    @Test
+    void testAllZeros() {
+        int[] nums = {0, 0, 0, 0};
+        int[] prefixSum = RangeSumQuery.buildPrefixSum(nums);
+
+        assertEquals(0, RangeSumQuery.sumRange(prefixSum, 0, 3));
+        assertEquals(0, RangeSumQuery.sumRange(prefixSum, 1, 2));
+    }
+
+    @Test
+    void testNegativeNumbers() {
+        int[] nums = {-1, 2, -3, 4};
+        int[] prefixSum = RangeSumQuery.buildPrefixSum(nums);
+
+        assertEquals(-2, RangeSumQuery.sumRange(prefixSum, 0, 2)); // -1+2-3
+        assertEquals(3, RangeSumQuery.sumRange(prefixSum, 1, 3)); // 2-3+4
+    }
+
+    @Test
+    void testEmptyArrayThrowsException() {
+        int[] nums = {};
+        int[] prefixSum = RangeSumQuery.buildPrefixSum(nums);
+
+        assertThrows(IllegalArgumentException.class, () -> RangeSumQuery.sumRange(prefixSum, 0, 0));
+    }
+
+    @Test
+    void testNullArrayThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> RangeSumQuery.buildPrefixSum(null));
+        assertThrows(IllegalArgumentException.class, () -> RangeSumQuery.sumRange(null, 0, 0));
+    }
+
+    @Test
+    void testInvalidIndicesThrowsException() {
+        int[] nums = {1, 2, 3};
+        int[] prefixSum = RangeSumQuery.buildPrefixSum(nums);
+
+        assertThrows(IllegalArgumentException.class, () -> RangeSumQuery.sumRange(prefixSum, -1, 2));
+        assertThrows(IllegalArgumentException.class, () -> RangeSumQuery.sumRange(prefixSum, 1, 5));
+        assertThrows(IllegalArgumentException.class, () -> RangeSumQuery.sumRange(prefixSum, 2, 1));
+    }
+}

From 7c38e5acd29a22e29c6954ae7088889a4afde689 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Fri, 20 Feb 2026 20:48:12 +0100
Subject: [PATCH 1197/1338] style: include `DM_NEXTINT_VIA_NEXTDOUBLE` (#7282)

---
 spotbugs-exclude.xml                                        | 3 ---
 .../com/thealgorithms/searches/LinearSearchThreadTest.java  | 6 ++++--
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index a8eedcfed402..13d72334e594 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -11,9 +11,6 @@
     <Match>
         <Bug pattern="RV_RETURN_VALUE_IGNORED_NO_SIDE_EFFECT" />
     </Match>
-    <Match>
-        <Bug pattern="DM_NEXTINT_VIA_NEXTDOUBLE" />
-    </Match>
     <Match>
         <Bug pattern="EI_EXPOSE_REP" />
     </Match>
diff --git a/src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java b/src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java
index 534c2a4487b2..c0d82489209f 100644
--- a/src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java
+++ b/src/test/java/com/thealgorithms/searches/LinearSearchThreadTest.java
@@ -3,6 +3,7 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.util.Random;
 import org.junit.jupiter.api.Test;
 
 class LinearSearchThreadTest {
@@ -62,10 +63,11 @@ void testSearcherEmptySegment() throws InterruptedException {
     void testSearcherRandomNumbers() throws InterruptedException {
         int size = 200;
         int[] array = new int[size];
+        Random random = new Random();
         for (int i = 0; i < size; i++) {
-            array[i] = (int) (Math.random() * 100);
+            array[i] = random.nextInt(100);
         }
-        int target = array[(int) (Math.random() * size)]; // Randomly select a target that is present
+        final int target = array[random.nextInt(size)]; // Randomly select a target that is present
         Searcher searcher = new Searcher(array, 0, size, target);
         searcher.start();
         searcher.join();

From 2d443a9991f7a80f1ab6bca437d1b953f7d05420 Mon Sep 17 00:00:00 2001
From: Mohan E <777emohan@gmail.com>
Date: Sat, 21 Feb 2026 18:40:37 +0530
Subject: [PATCH 1198/1338] Add time and space complexity documentation to
 LongestNonRepetitiveSubstring (#7284)

---
 .../strings/LongestNonRepetitiveSubstring.java              | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java b/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java
index 6808cd50602f..51e8dc6b02c3 100644
--- a/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java
+++ b/src/main/java/com/thealgorithms/strings/LongestNonRepetitiveSubstring.java
@@ -13,6 +13,12 @@ private LongestNonRepetitiveSubstring() {
     /**
      * Finds the length of the longest substring without repeating characters.
      *
+     * Uses the sliding window technique with a HashMap to track
+     * the last seen index of each character.
+     *
+     * Time Complexity: O(n), where n is the length of the input string.
+     * Space Complexity: O(min(n, m)), where m is the size of the character set.
+     *
      * @param s the input string
      * @return the length of the longest non-repetitive substring
      */

From 109df1f39837d0102646920dcfa353ae3c09e7cc Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Sat, 21 Feb 2026 16:27:13 +0100
Subject: [PATCH 1199/1338] style: include `SUA_SUSPICIOUS_UNINITIALIZED_ARRAY`
 (#7285)

---
 spotbugs-exclude.xml                                      | 3 ---
 .../com/thealgorithms/divideandconquer/ClosestPair.java   | 4 ----
 .../thealgorithms/divideandconquer/ClosestPairTest.java   | 8 --------
 3 files changed, 15 deletions(-)

diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 13d72334e594..8c42802520e3 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -96,9 +96,6 @@
     <Match>
         <Bug pattern="UCPM_USE_CHARACTER_PARAMETERIZED_METHOD" />
     </Match>
-    <Match>
-        <Bug pattern="SUA_SUSPICIOUS_UNINITIALIZED_ARRAY" />
-    </Match>
     <Match>
         <Bug pattern="SPP_USE_MATH_CONSTANT" />
     </Match>
diff --git a/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java b/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java
index 4c9c40c83174..323098a99887 100644
--- a/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java
+++ b/src/main/java/com/thealgorithms/divideandconquer/ClosestPair.java
@@ -66,10 +66,6 @@ public static class Location {
         }
     }
 
-    public Location[] createLocation(int numberValues) {
-        return new Location[numberValues];
-    }
-
     public Location buildLocation(double x, double y) {
         return new Location(x, y);
     }
diff --git a/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java b/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java
index 38784228d68e..b25fd796b112 100644
--- a/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java
+++ b/src/test/java/com/thealgorithms/divideandconquer/ClosestPairTest.java
@@ -16,14 +16,6 @@ public void testBuildLocation() {
         assertEquals(4.0, point.y);
     }
 
-    @Test
-    public void testCreateLocation() {
-        ClosestPair cp = new ClosestPair(5);
-        ClosestPair.Location[] locations = cp.createLocation(5);
-        assertNotNull(locations);
-        assertEquals(5, locations.length);
-    }
-
     @Test
     public void testXPartition() {
         ClosestPair cp = new ClosestPair(5);

From 12935c291def0a4079c961a0aa7652177b1b05f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=87a=C4=9Flar=20Eker?= <ekercaglar@gmail.com>
Date: Sun, 22 Feb 2026 21:15:22 +0300
Subject: [PATCH 1200/1338] Add Longest Repeated Substring algorithm (#7286)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Add Longest Repeated Substring algorithm

Implement LongestRepeatedSubstring in the strings package using the
existing SuffixArray and Kasai's algorithm for LCP array construction.
Includes parameterized unit tests covering typical and edge cases.

* style: reformat test file per clang-format and add coverage test

---------

Co-authored-by: Çağlar Eker <eker.caglar@hepsiburada.com>
---
 .../strings/LongestRepeatedSubstring.java     | 83 +++++++++++++++++++
 .../strings/LongestRepeatedSubstringTest.java | 33 ++++++++
 2 files changed, 116 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/LongestRepeatedSubstring.java
 create mode 100644 src/test/java/com/thealgorithms/strings/LongestRepeatedSubstringTest.java

diff --git a/src/main/java/com/thealgorithms/strings/LongestRepeatedSubstring.java b/src/main/java/com/thealgorithms/strings/LongestRepeatedSubstring.java
new file mode 100644
index 000000000000..87c9278fd4bf
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/LongestRepeatedSubstring.java
@@ -0,0 +1,83 @@
+package com.thealgorithms.strings;
+
+/**
+ * Finds the longest substring that occurs at least twice in a given string.
+ *
+ * <p>Uses the suffix array (via {@link SuffixArray}) and Kasai's algorithm
+ * to build the LCP (Longest Common Prefix) array, then returns the substring
+ * corresponding to the maximum LCP value.</p>
+ *
+ * <p>Time complexity: O(n log² n) for suffix array construction + O(n) for LCP.</p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Longest_repeated_substring_problem">Longest repeated substring problem</a>
+ * @see SuffixArray
+ */
+public final class LongestRepeatedSubstring {
+
+    private LongestRepeatedSubstring() {
+    }
+
+    /**
+     * Returns the longest substring that appears at least twice in the given text.
+     *
+     * @param text the input string
+     * @return the longest repeated substring, or an empty string if none exists
+     */
+    public static String longestRepeatedSubstring(String text) {
+        if (text == null || text.length() <= 1) {
+            return "";
+        }
+
+        final int[] suffixArray = SuffixArray.buildSuffixArray(text);
+        final int[] lcp = buildLcpArray(text, suffixArray);
+
+        int maxLen = 0;
+        int maxIdx = 0;
+        for (int i = 0; i < lcp.length; i++) {
+            if (lcp[i] > maxLen) {
+                maxLen = lcp[i];
+                maxIdx = suffixArray[i + 1];
+            }
+        }
+
+        return text.substring(maxIdx, maxIdx + maxLen);
+    }
+
+    /**
+     * Builds the LCP (Longest Common Prefix) array using Kasai's algorithm.
+     *
+     * <p>LCP[i] is the length of the longest common prefix between the suffixes
+     * at positions suffixArray[i] and suffixArray[i+1] in sorted order.</p>
+     *
+     * @param text the original string
+     * @param suffixArray the suffix array of the string
+     * @return the LCP array of length n-1
+     */
+    static int[] buildLcpArray(String text, int[] suffixArray) {
+        final int n = text.length();
+        final int[] rank = new int[n];
+        final int[] lcp = new int[n - 1];
+
+        for (int i = 0; i < n; i++) {
+            rank[suffixArray[i]] = i;
+        }
+
+        int k = 0;
+        for (int i = 0; i < n; i++) {
+            if (rank[i] == n - 1) {
+                k = 0;
+                continue;
+            }
+            final int j = suffixArray[rank[i] + 1];
+            while (i + k < n && j + k < n && text.charAt(i + k) == text.charAt(j + k)) {
+                k++;
+            }
+            lcp[rank[i]] = k;
+            if (k > 0) {
+                k--;
+            }
+        }
+
+        return lcp;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/LongestRepeatedSubstringTest.java b/src/test/java/com/thealgorithms/strings/LongestRepeatedSubstringTest.java
new file mode 100644
index 000000000000..366f6863340d
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/LongestRepeatedSubstringTest.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class LongestRepeatedSubstringTest {
+
+    @ParameterizedTest(name = "\"{0}\" -> \"{1}\"")
+    @MethodSource("provideTestCases")
+    void testLongestRepeatedSubstring(String input, String expected) {
+        assertEquals(expected, LongestRepeatedSubstring.longestRepeatedSubstring(input));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of("banana", "ana"), Arguments.of("abcabc", "abc"), Arguments.of("aaaa", "aaa"), Arguments.of("abcd", ""), Arguments.of("a", ""), Arguments.of("", ""), Arguments.of(null, ""), Arguments.of("aab", "a"), Arguments.of("aa", "a"), Arguments.of("mississippi", "issi"));
+    }
+
+    @ParameterizedTest(name = "\"{0}\" -> LCP={1}")
+    @MethodSource("provideLcpTestCases")
+    void testBuildLcpArray(String input, int[] expectedLcp) {
+        int[] suffixArray = SuffixArray.buildSuffixArray(input);
+        assertArrayEquals(expectedLcp, LongestRepeatedSubstring.buildLcpArray(input, suffixArray));
+    }
+
+    private static Stream<Arguments> provideLcpTestCases() {
+        return Stream.of(Arguments.of("banana", new int[] {1, 3, 0, 0, 2}), Arguments.of("ab", new int[] {0}));
+    }
+}

From 10114b79ae8869e9351c8fd38eca798978119204 Mon Sep 17 00:00:00 2001
From: Vasundhara117 <vasu11devi@gmail.com>
Date: Tue, 24 Feb 2026 00:36:51 +0530
Subject: [PATCH 1201/1338] Add ReverseQueueRecursion.java: Reverse a Queue
 using recursion (#7281)

* Create ReverseQueueRecursion

Add ReverseQueueRecursion.java:
- Reverses a Queue using recursion (generic <T>)
- Includes unit tests in ReverseQueueRecursionTest.java
- Follows repo style (final class, private constructor, Javadoc)

* Create ReverseQueueRecursionTest.java

Add ReverseQueueRecursionTest as required by CONTRIBUTING.md

* Rename ReverseQueueRecursion to ReverseQueueRecursion.java

* Update ReverseQueueRecursion.java

* Update ReverseQueueRecursion.java

* Update ReverseQueueRecursion.java

* Update ReverseQueueRecursion.java

* Update ReverseQueueRecursionTest.java

* Update ReverseQueueRecursion.java

* Update ReverseQueueRecursionTest.java

* Update ReverseQueueRecursionTest.java

* Update ReverseQueueRecursion.java

* Update ReverseQueueRecursionTest.java

* Update ReverseQueueRecursionTest.java

* Update ReverseQueueRecursionTest.java

* Update ReverseQueueRecursionTest.java

* Update ReverseQueueRecursion.java
---
 .../queues/ReverseQueueRecursion.java         | 28 ++++++++++
 .../queues/ReverseQueueRecursionTest.java     | 54 +++++++++++++++++++
 2 files changed, 82 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/queues/ReverseQueueRecursion.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/queues/ReverseQueueRecursionTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/ReverseQueueRecursion.java b/src/main/java/com/thealgorithms/datastructures/queues/ReverseQueueRecursion.java
new file mode 100644
index 000000000000..79275dcefe20
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/queues/ReverseQueueRecursion.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.datastructures.queues;
+
+import java.util.Queue;
+
+/**
+ * Reverse a queue using recursion.
+ */
+public final class ReverseQueueRecursion {
+    private ReverseQueueRecursion() {
+        // private constructor to prevent instantiation
+    }
+
+    /**
+     * Reverses the given queue recursively.
+     *
+     * @param queue the queue to reverse
+     * @param <T> the type of elements in the queue
+     */
+    public static <T> void reverseQueue(final Queue<T> queue) {
+        if (queue == null || queue.isEmpty()) {
+            return;
+        }
+
+        final T front = queue.poll();
+        reverseQueue(queue);
+        queue.add(front);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/ReverseQueueRecursionTest.java b/src/test/java/com/thealgorithms/datastructures/queues/ReverseQueueRecursionTest.java
new file mode 100644
index 000000000000..e3abe15b6a46
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/queues/ReverseQueueRecursionTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.datastructures.queues;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.LinkedList;
+import java.util.Queue;
+import org.junit.jupiter.api.Test;
+
+class ReverseQueueRecursionTest {
+    @Test
+    void testReverseMultipleElements() {
+        Queue<Integer> queue = new LinkedList<>();
+        queue.add(1);
+        queue.add(2);
+        queue.add(3);
+        queue.add(4);
+        ReverseQueueRecursion.reverseQueue(queue);
+        assertEquals(4, queue.poll());
+        assertEquals(3, queue.poll());
+        assertEquals(2, queue.poll());
+        assertEquals(1, queue.poll());
+        assertTrue(queue.isEmpty());
+    }
+
+    @Test
+    void testReverseSingleElement() {
+        Queue<Integer> queue = new LinkedList<>();
+        queue.add(42);
+        ReverseQueueRecursion.reverseQueue(queue);
+        assertEquals(42, queue.poll());
+        assertTrue(queue.isEmpty());
+    }
+
+    @Test
+    void testReverseEmptyQueue() {
+        Queue<Integer> queue = new LinkedList<>();
+        ReverseQueueRecursion.reverseQueue(queue);
+        assertTrue(queue.isEmpty());
+    }
+
+    @Test
+    void testReverseStringQueue() {
+        Queue<String> queue = new LinkedList<>();
+        queue.add("A");
+        queue.add("B");
+        queue.add("C");
+        ReverseQueueRecursion.reverseQueue(queue);
+        assertEquals("C", queue.poll());
+        assertEquals("B", queue.poll());
+        assertEquals("A", queue.poll());
+        assertTrue(queue.isEmpty());
+    }
+}

From 023f856a9bca320e5ab4324e3efb4766ae2f4f54 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 23 Feb 2026 22:55:11 +0100
Subject: [PATCH 1202/1338] chore(deps-dev): bump
 org.apache.maven.plugins:maven-surefire-plugin from 3.5.4 to 3.5.5 (#7288)

chore(deps-dev): bump org.apache.maven.plugins:maven-surefire-plugin

Bumps [org.apache.maven.plugins:maven-surefire-plugin](https://github.com/apache/maven-surefire) from 3.5.4 to 3.5.5.
- [Release notes](https://github.com/apache/maven-surefire/releases)
- [Commits](https://github.com/apache/maven-surefire/compare/surefire-3.5.4...surefire-3.5.5)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-surefire-plugin
  dependency-version: 3.5.5
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 2445a1e920a8..96deca50fea8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -61,7 +61,7 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.5.4</version>
+                <version>3.5.5</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>

From 7e5d9d469d8d2deb7309a1003dafdeb884c7dd84 Mon Sep 17 00:00:00 2001
From: Chahat Sandhu <chahat@disroot.org>
Date: Thu, 26 Feb 2026 05:27:11 -0600
Subject: [PATCH 1203/1338] feat: add HuffmanCoding with fail-fast validation
 and immutable design (#7289)

---
 .../compression/HuffmanCoding.java            | 253 ++++++++++++++++++
 .../compression/HuffmanCodingTest.java        | 110 ++++++++
 2 files changed, 363 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/compression/HuffmanCoding.java
 create mode 100644 src/test/java/com/thealgorithms/compression/HuffmanCodingTest.java

diff --git a/src/main/java/com/thealgorithms/compression/HuffmanCoding.java b/src/main/java/com/thealgorithms/compression/HuffmanCoding.java
new file mode 100644
index 000000000000..d7f9d58d2429
--- /dev/null
+++ b/src/main/java/com/thealgorithms/compression/HuffmanCoding.java
@@ -0,0 +1,253 @@
+package com.thealgorithms.compression;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.PriorityQueue;
+
+/**
+ * Huffman Coding Compression Algorithm Implementation.
+ * <p>
+ * Huffman Coding is a popular greedy algorithm used for lossless data compression.
+ * It reduces the overall size of data by assigning variable-length, prefix-free
+ * binary codes to input characters, ensuring that more frequent characters receive
+ * the shortest possible codes.
+ * </p>
+ * <p>
+ * <strong>Key Features:</strong>
+ * <ul>
+ * <li>Uses a PriorityQueue (min-heap) to efficiently construct the optimal prefix tree.</li>
+ * <li>Fail-fast design throws exceptions for unsupported characters and malformed binary payloads.</li>
+ * <li>Immutable internal dictionary state prevents external tampering with generated codes.</li>
+ * <li>Robust handling of edge cases, including single-character strings and incomplete sequences.</li>
+ * </ul>
+ * </p>
+ * @author Chahat Sandhu, <a href="https://github.com/singhc7">singhc7</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Huffman_coding">Huffman Coding (Wikipedia)</a>
+ */
+public class HuffmanCoding {
+
+    private Node root;
+    private final Map<Character, String> huffmanCodes;
+
+    /**
+     * Represents a node within the Huffman Tree.
+     * Implements {@link Comparable} to allow sorting by frequency in a PriorityQueue.
+     */
+    private static class Node implements Comparable<Node> {
+        final char ch;
+        final int freq;
+        final Node left;
+        final Node right;
+
+        /**
+         * Constructs a leaf node containing a specific character and its frequency.
+         *
+         * @param ch   The character stored in this leaf.
+         * @param freq The frequency of occurrence of the character.
+         */
+        Node(char ch, int freq) {
+            this.ch = ch;
+            this.freq = freq;
+            this.left = null;
+            this.right = null;
+        }
+
+        /**
+         * Constructs an internal node that merges two child nodes.
+         * The character is defaulted to the null character ('\0').
+         *
+         * @param freq  The combined frequency of the left and right child nodes.
+         * @param left  The left child node.
+         * @param right The right child node.
+         */
+        Node(int freq, Node left, Node right) {
+            this.ch = '\0';
+            this.freq = freq;
+            this.left = left;
+            this.right = right;
+        }
+
+        /**
+         * Determines if the current node is a leaf (contains no children).
+         *
+         * @return {@code true} if both left and right children are null, {@code false} otherwise.
+         */
+        boolean isLeaf() {
+            return left == null && right == null;
+        }
+
+        /**
+         * Compares this node with another node based on their frequencies.
+         * Used by the PriorityQueue to maintain the min-heap property.
+         *
+         * @param other The other Node to compare against.
+         * @return A negative integer, zero, or a positive integer as this node's frequency
+         * is less than, equal to, or greater than the specified node's frequency.
+         */
+        @Override
+        public int compareTo(Node other) {
+            return Integer.compare(this.freq, other.freq);
+        }
+    }
+
+    /**
+     * Initializes the Huffman Tree and generates immutable prefix-free codes
+     * based on the character frequencies in the provided text.
+     *
+     * @param text The input string used to calculate frequencies and build the optimal tree.
+     * If null or empty, an empty tree and dictionary are created.
+     */
+    public HuffmanCoding(String text) {
+        if (text == null || text.isEmpty()) {
+            this.huffmanCodes = Collections.emptyMap();
+            return;
+        }
+
+        Map<Character, String> tempCodes = new HashMap<>();
+        buildTree(text);
+        generateCodes(root, "", tempCodes);
+
+        if (tempCodes.size() == 1) {
+            tempCodes.put(root.ch, "0");
+        }
+
+        this.huffmanCodes = Collections.unmodifiableMap(tempCodes);
+    }
+
+    /**
+     * Computes character frequencies and constructs the Huffman Tree using a min-heap.
+     * The optimal tree is built by repeatedly extracting the two lowest-frequency nodes
+     * and merging them until a single root node remains.
+     *
+     * @param text The input text to analyze.
+     */
+    private void buildTree(String text) {
+        Map<Character, Integer> freqMap = new HashMap<>();
+        for (char c : text.toCharArray()) {
+            freqMap.put(c, freqMap.getOrDefault(c, 0) + 1);
+        }
+
+        PriorityQueue<Node> pq = new PriorityQueue<>();
+        for (Map.Entry<Character, Integer> entry : freqMap.entrySet()) {
+            pq.add(new Node(entry.getKey(), entry.getValue()));
+        }
+
+        while (pq.size() > 1) {
+            Node left = pq.poll();
+            Node right = pq.poll();
+            pq.add(new Node(left.freq + right.freq, left, right));
+        }
+
+        root = pq.poll();
+    }
+
+    /**
+     * Recursively traverses the Huffman Tree to generate prefix-free binary codes.
+     * Left traversals append a '0' to the code, while right traversals append a '1'.
+     *
+     * @param node The current node in the traversal.
+     * @param code The accumulated binary string for the current path.
+     * @param map  The temporary dictionary to populate with the final character-to-code mappings.
+     */
+    private void generateCodes(Node node, String code, Map<Character, String> map) {
+        if (node == null) {
+            return;
+        }
+        if (node.isLeaf()) {
+            map.put(node.ch, code);
+            return;
+        }
+        generateCodes(node.left, code + "0", map);
+        generateCodes(node.right, code + "1", map);
+    }
+
+    /**
+     * Encodes the given plaintext string into a binary string using the generated Huffman dictionary.
+     *
+     * @param text The plaintext string to compress.
+     * @return A string of '0's and '1's representing the compressed data.
+     * Returns an empty string if the input is null or empty.
+     * @throws IllegalStateException    If attempting to encode when the Huffman tree is empty.
+     * @throws IllegalArgumentException If the input text contains a character not present
+     * in the original text used to build the tree.
+     */
+    public String encode(String text) {
+        if (text == null || text.isEmpty()) {
+            return "";
+        }
+        if (root == null) {
+            throw new IllegalStateException("Huffman tree is empty.");
+        }
+
+        StringBuilder sb = new StringBuilder();
+        for (char c : text.toCharArray()) {
+            if (!huffmanCodes.containsKey(c)) {
+                throw new IllegalArgumentException(String.format("Character '%c' (U+%04X) not found in Huffman dictionary.", c, (int) c));
+            }
+            sb.append(huffmanCodes.get(c));
+        }
+        return sb.toString();
+    }
+
+    /**
+     * Decodes the given binary string back into the original plaintext using the Huffman Tree.
+     * Validates the integrity of the binary payload during traversal.
+     *
+     * @param encodedText The binary string of '0's and '1's to decompress.
+     * @return The reconstructed plaintext string. Returns an empty string if the input is null or empty.
+     * @throws IllegalStateException    If attempting to decode when the Huffman tree is empty.
+     * @throws IllegalArgumentException If the binary string contains characters other than '0' or '1',
+     * or if the sequence ends abruptly without reaching a leaf node.
+     */
+    public String decode(String encodedText) {
+        if (encodedText == null || encodedText.isEmpty()) {
+            return "";
+        }
+        if (root == null) {
+            throw new IllegalStateException("Huffman tree is empty.");
+        }
+
+        StringBuilder sb = new StringBuilder();
+
+        if (root.isLeaf()) {
+            for (char bit : encodedText.toCharArray()) {
+                if (bit != '0') {
+                    throw new IllegalArgumentException("Invalid binary sequence for single-character tree.");
+                }
+                sb.append(root.ch);
+            }
+            return sb.toString();
+        }
+
+        Node current = root;
+        for (char bit : encodedText.toCharArray()) {
+            if (bit != '0' && bit != '1') {
+                throw new IllegalArgumentException("Encoded text contains invalid characters: " + bit);
+            }
+
+            current = (bit == '0') ? current.left : current.right;
+
+            if (current.isLeaf()) {
+                sb.append(current.ch);
+                current = root;
+            }
+        }
+
+        if (current != root) {
+            throw new IllegalArgumentException("Malformed encoded string: incomplete sequence ending.");
+        }
+
+        return sb.toString();
+    }
+
+    /**
+     * Retrieves the generated Huffman dictionary mapping characters to their binary codes.
+     *
+     * @return An unmodifiable map containing the character-to-binary-code mappings to prevent
+     * external mutation of the algorithm's state.
+     */
+    public Map<Character, String> getHuffmanCodes() {
+        return huffmanCodes;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/compression/HuffmanCodingTest.java b/src/test/java/com/thealgorithms/compression/HuffmanCodingTest.java
new file mode 100644
index 000000000000..f919417899db
--- /dev/null
+++ b/src/test/java/com/thealgorithms/compression/HuffmanCodingTest.java
@@ -0,0 +1,110 @@
+package com.thealgorithms.compression;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class HuffmanCodingTest {
+
+    @Test
+    void testStandardLifecycle() {
+        String input = "efficiency is key";
+        HuffmanCoding huffman = new HuffmanCoding(input);
+
+        String encoded = huffman.encode(input);
+        assertNotNull(encoded);
+        assertTrue(encoded.matches("[01]+"));
+        assertEquals(input, huffman.decode(encoded));
+    }
+
+    @Test
+    void testNullAndEmptyHandling() {
+        HuffmanCoding huffman = new HuffmanCoding("");
+        assertEquals("", huffman.encode(""));
+        assertEquals("", huffman.decode(""));
+
+        HuffmanCoding huffmanNull = new HuffmanCoding(null);
+        assertEquals("", huffmanNull.encode(null));
+        assertEquals("", huffmanNull.decode(null));
+    }
+
+    @Test
+    void testSingleCharacterEdgeCase() {
+        String input = "aaaaa";
+        HuffmanCoding huffman = new HuffmanCoding(input);
+
+        String encoded = huffman.encode(input);
+        assertEquals("00000", encoded);
+        assertEquals(input, huffman.decode(encoded));
+    }
+
+    @Test
+    void testUnicodeAndSpecialCharacters() {
+        // Tests spacing, symbols, non-latin alphabets, and surrogate pairs (emojis)
+        String input = "Hello, World! 🚀\nLine 2: こんにちは";
+        HuffmanCoding huffman = new HuffmanCoding(input);
+
+        String encoded = huffman.encode(input);
+        assertEquals(input, huffman.decode(encoded));
+    }
+
+    @Test
+    void testFailFastOnUnseenCharacter() {
+        HuffmanCoding huffman = new HuffmanCoding("abc");
+
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class,
+            () -> huffman.encode("abcd") // 'd' was not in the original tree
+        );
+        assertTrue(exception.getMessage().contains("not found in Huffman dictionary"));
+    }
+
+    @Test
+    void testFailFastOnInvalidBinaryCharacter() {
+        HuffmanCoding huffman = new HuffmanCoding("abc");
+        String encoded = huffman.encode("abc");
+
+        // Inject a '2' into the binary stream
+        String corruptedEncoded = encoded + "2";
+
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> huffman.decode(corruptedEncoded));
+        assertTrue(exception.getMessage().contains("contains invalid characters"));
+    }
+
+    @Test
+    void testFailFastOnIncompleteSequence() {
+        HuffmanCoding huffman = new HuffmanCoding("abcd");
+        String encoded = huffman.encode("abc");
+
+        // Truncate the last bit to simulate an incomplete byte/sequence transfer
+        String truncatedEncoded = encoded.substring(0, encoded.length() - 1);
+
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> huffman.decode(truncatedEncoded));
+        assertTrue(exception.getMessage().contains("incomplete sequence"));
+    }
+
+    @Test
+    void testImmutabilityOfDictionary() {
+        HuffmanCoding huffman = new HuffmanCoding("abc");
+        var codes = huffman.getHuffmanCodes();
+
+        assertThrows(UnsupportedOperationException.class, () -> codes.put('z', "0101"));
+    }
+
+    @Test
+    void testStressVolume() {
+        StringBuilder sb = new StringBuilder();
+        // Generate a 100,000 character string
+        for (int i = 0; i < 100000; i++) {
+            sb.append((char) ('a' + (i % 26)));
+        }
+        String largeInput = sb.toString();
+
+        HuffmanCoding huffman = new HuffmanCoding(largeInput);
+        String encoded = huffman.encode(largeInput);
+
+        assertEquals(largeInput, huffman.decode(encoded));
+    }
+}

From 705eb52833f50e88b1f92d309ac40f770fa56b10 Mon Sep 17 00:00:00 2001
From: kvadrik <41710943+kvadrik@users.noreply.github.com>
Date: Fri, 27 Feb 2026 23:35:42 +0200
Subject: [PATCH 1204/1338] Added volume of a pyramid frustum (#7291)

* Added volume of a pyramid frustum

Added a function calculating volume of a pyramid frustum, V=(S1+S2+sqrt(S1*S2))*h/3

* compiler error fixed

* Added pyramid frustum test case

* extra space removed
---
 src/main/java/com/thealgorithms/maths/Volume.java    | 12 ++++++++++++
 .../java/com/thealgorithms/maths/VolumeTest.java     |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/src/main/java/com/thealgorithms/maths/Volume.java b/src/main/java/com/thealgorithms/maths/Volume.java
index 0f282b2abae2..89b0595912b9 100644
--- a/src/main/java/com/thealgorithms/maths/Volume.java
+++ b/src/main/java/com/thealgorithms/maths/Volume.java
@@ -102,4 +102,16 @@ public static double volumePyramid(double baseArea, double height) {
     public static double volumeFrustumOfCone(double r1, double r2, double height) {
         return (Math.PI * height / 3) * (r1 * r1 + r2 * r2 + r1 * r2);
     }
+
+    /**
+     * Calculate the volume of a frustum of a pyramid.
+     *
+     * @param upperBaseArea area of the upper base
+     * @param lowerBaseArea area of the lower base
+     * @param height height of the frustum
+     * @return volume of the frustum
+     */
+    public static double volumeFrustumOfPyramid(double upperBaseArea, double lowerBaseArea, double height) {
+        return (upperBaseArea + lowerBaseArea + Math.sqrt(upperBaseArea * lowerBaseArea)) * height / 3;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/maths/VolumeTest.java b/src/test/java/com/thealgorithms/maths/VolumeTest.java
index af882eef7563..cf72d7084e75 100644
--- a/src/test/java/com/thealgorithms/maths/VolumeTest.java
+++ b/src/test/java/com/thealgorithms/maths/VolumeTest.java
@@ -35,5 +35,8 @@ public void volume() {
 
         /* test frustum */
         assertEquals(359.188760060433, Volume.volumeFrustumOfCone(3, 5, 7));
+
+        /* test pyramid frustum */
+        assertEquals(140.0, Volume.volumeFrustumOfPyramid(6, 24, 10));
     }
 }

From ba286b24d66972150547fc6683eaa1925743e9d5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 27 Feb 2026 22:52:50 +0100
Subject: [PATCH 1205/1338] chore(deps-dev): bump org.mockito:mockito-core from
 5.21.0 to 5.22.0 (#7292)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.21.0 to 5.22.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.21.0...v5.22.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.22.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 96deca50fea8..7c614f31e52e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.21.0</version>
+            <version>5.22.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 0d2a98e9f87dc7bd5dde732a8d34a6bcaef43400 Mon Sep 17 00:00:00 2001
From: kvadrik <41710943+kvadrik@users.noreply.github.com>
Date: Sat, 28 Feb 2026 21:08:50 +0200
Subject: [PATCH 1206/1338] Added volume of a torus (#7294)

* Added volume of a torus

Added function calculation the volume of a torus according to the formula:
V = 2 * pi^2 * R * r^2
where R is the major radius and r is the minor radius of the torus.

* Added test for torus volume
---
 src/main/java/com/thealgorithms/maths/Volume.java     | 11 +++++++++++
 src/test/java/com/thealgorithms/maths/VolumeTest.java |  3 +++
 2 files changed, 14 insertions(+)

diff --git a/src/main/java/com/thealgorithms/maths/Volume.java b/src/main/java/com/thealgorithms/maths/Volume.java
index 89b0595912b9..c0898c5424a0 100644
--- a/src/main/java/com/thealgorithms/maths/Volume.java
+++ b/src/main/java/com/thealgorithms/maths/Volume.java
@@ -114,4 +114,15 @@ public static double volumeFrustumOfCone(double r1, double r2, double height) {
     public static double volumeFrustumOfPyramid(double upperBaseArea, double lowerBaseArea, double height) {
         return (upperBaseArea + lowerBaseArea + Math.sqrt(upperBaseArea * lowerBaseArea)) * height / 3;
     }
+
+    /**
+     * Calculate the volume of a torus.
+     *
+     * @param majorRadius major radius of a torus
+     * @param minorRadius minor radius of a torus
+     * @return volume of the torus
+     */
+    public static double volumeTorus(double majorRadius, double minorRadius) {
+        return 2 * Math.PI * Math.PI * majorRadius * minorRadius * minorRadius;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/maths/VolumeTest.java b/src/test/java/com/thealgorithms/maths/VolumeTest.java
index cf72d7084e75..c159d7566b46 100644
--- a/src/test/java/com/thealgorithms/maths/VolumeTest.java
+++ b/src/test/java/com/thealgorithms/maths/VolumeTest.java
@@ -38,5 +38,8 @@ public void volume() {
 
         /* test pyramid frustum */
         assertEquals(140.0, Volume.volumeFrustumOfPyramid(6, 24, 10));
+
+        /* test torus */
+        assertEquals(39.47841760435743, Volume.volumeTorus(2, 1));
     }
 }

From d8672882bfebc8cf85f184da461880c84aa7cb92 Mon Sep 17 00:00:00 2001
From: kvadrik <41710943+kvadrik@users.noreply.github.com>
Date: Sat, 28 Feb 2026 21:13:19 +0200
Subject: [PATCH 1207/1338] Added surface area of a cuboid (#7293)

* Added surface area of a cuboid

Added surface area of a cuboid according to the formula:
S = 2 * (ab + ac + bc)

* Removed extra white space

* Added test for cuboid surface area

* fixed syntax error

* Removed extra space

* Added tests for cuboid surface area that should fail

I have added tests for cuboid surface area where one of the parameters is invalid. These should fail.
---
 .../java/com/thealgorithms/maths/Area.java    | 21 +++++++++++++++++++
 .../com/thealgorithms/maths/AreaTest.java     | 11 ++++++++++
 2 files changed, 32 insertions(+)

diff --git a/src/main/java/com/thealgorithms/maths/Area.java b/src/main/java/com/thealgorithms/maths/Area.java
index 08807580cb03..84fc67159379 100644
--- a/src/main/java/com/thealgorithms/maths/Area.java
+++ b/src/main/java/com/thealgorithms/maths/Area.java
@@ -35,6 +35,27 @@ public static double surfaceAreaCube(final double sideLength) {
         return 6 * sideLength * sideLength;
     }
 
+    /**
+     * Calculate the surface area of a cuboid.
+     *
+     * @param length length of the cuboid
+     * @param width width of the cuboid
+     * @param height height of the cuboid
+     * @return surface area of given cuboid
+     */
+    public static double surfaceAreaCuboid(final double length, double width, double height) {
+        if (length <= 0) {
+            throw new IllegalArgumentException("Length must be greater than 0");
+        }
+        if (width <= 0) {
+            throw new IllegalArgumentException("Width must be greater than 0");
+        }
+        if (height <= 0) {
+            throw new IllegalArgumentException("Height must be greater than 0");
+        }
+        return 2 * (length * width + length * height + width * height);
+    }
+
     /**
      * Calculate the surface area of a sphere.
      *
diff --git a/src/test/java/com/thealgorithms/maths/AreaTest.java b/src/test/java/com/thealgorithms/maths/AreaTest.java
index b28afb85fbc3..1c2fe53ff3f3 100644
--- a/src/test/java/com/thealgorithms/maths/AreaTest.java
+++ b/src/test/java/com/thealgorithms/maths/AreaTest.java
@@ -16,6 +16,11 @@ void testSurfaceAreaCube() {
         assertEquals(6.0, Area.surfaceAreaCube(1));
     }
 
+    @Test
+    void testSurfaceAreaCuboid() {
+        assertEquals(214.0, Area.surfaceAreaCuboid(5, 6, 7));
+    }
+
     @Test
     void testSurfaceAreaSphere() {
         assertEquals(12.566370614359172, Area.surfaceAreaSphere(1));
@@ -70,6 +75,12 @@ void surfaceAreaCone() {
     void testAllIllegalInput() {
         assertAll(()
                       -> assertThrows(IllegalArgumentException.class, () -> Area.surfaceAreaCube(0)),
+            ()
+                -> assertThrows(IllegalArgumentException.class, () -> Area.surfaceAreaCuboid(0, 1, 2)),
+            ()
+                -> assertThrows(IllegalArgumentException.class, () -> Area.surfaceAreaCuboid(1, 0, 2)),
+            ()
+                -> assertThrows(IllegalArgumentException.class, () -> Area.surfaceAreaCuboid(1, 2, 0)),
             ()
                 -> assertThrows(IllegalArgumentException.class, () -> Area.surfaceAreaSphere(0)),
             ()

From 4b04ad4a836ad87d6d4adf3bf395c0aade96bb07 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 2 Mar 2026 19:56:39 +0100
Subject: [PATCH 1208/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.2.0 to 13.3.0 (#7295)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.2.0 to 13.3.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.2.0...checkstyle-13.3.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.3.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: a <19151554+alxkm@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 7c614f31e52e..b2192fb9a64a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.2.0</version>
+                    <version>13.3.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 9875648a835ac49b9502c0b6c4816780b4f0462b Mon Sep 17 00:00:00 2001
From: Alex Tumanov <oleksii.tumanov@gmail.com>
Date: Thu, 5 Mar 2026 07:34:33 -0600
Subject: [PATCH 1209/1338] feat: add TopKFrequentWords with deterministic
 tie-breaking (#7298) (#7297)

* feat: add TopKFrequentWords with deterministic tie-breaking

* style: format TopKFrequentWords files with clang-format
---
 .../strings/TopKFrequentWords.java            | 56 +++++++++++++++++++
 .../strings/TopKFrequentWordsTest.java        | 34 +++++++++++
 2 files changed, 90 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/TopKFrequentWords.java
 create mode 100644 src/test/java/com/thealgorithms/strings/TopKFrequentWordsTest.java

diff --git a/src/main/java/com/thealgorithms/strings/TopKFrequentWords.java b/src/main/java/com/thealgorithms/strings/TopKFrequentWords.java
new file mode 100644
index 000000000000..106de304cf40
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/TopKFrequentWords.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.strings;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Utility class to find the top-k most frequent words.
+ *
+ * <p>Words are ranked by frequency in descending order. For equal frequencies,
+ * words are ranked in lexicographical ascending order.
+ *
+ * <p>Reference:
+ * https://en.wikipedia.org/wiki/Top-k_problem
+ *
+ */
+public final class TopKFrequentWords {
+    private TopKFrequentWords() {
+    }
+
+    /**
+     * Finds the k most frequent words.
+     *
+     * @param words input array of words
+     * @param k number of words to return
+     * @return list of top-k words ordered by frequency then lexicographical order
+     * @throws IllegalArgumentException if words is null, k is negative, or words contains null
+     */
+    public static List<String> findTopKFrequentWords(String[] words, int k) {
+        if (words == null) {
+            throw new IllegalArgumentException("Input words array cannot be null.");
+        }
+        if (k < 0) {
+            throw new IllegalArgumentException("k cannot be negative.");
+        }
+        if (k == 0 || words.length == 0) {
+            return List.of();
+        }
+
+        Map<String, Integer> frequency = new HashMap<>();
+        for (String word : words) {
+            if (word == null) {
+                throw new IllegalArgumentException("Input words cannot contain null values.");
+            }
+            frequency.put(word, frequency.getOrDefault(word, 0) + 1);
+        }
+
+        List<String> candidates = new ArrayList<>(frequency.keySet());
+        candidates.sort(Comparator.<String>comparingInt(frequency::get).reversed().thenComparing(Comparator.naturalOrder()));
+
+        int limit = Math.min(k, candidates.size());
+        return new ArrayList<>(candidates.subList(0, limit));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/TopKFrequentWordsTest.java b/src/test/java/com/thealgorithms/strings/TopKFrequentWordsTest.java
new file mode 100644
index 000000000000..42b2d04ff265
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/TopKFrequentWordsTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class TopKFrequentWordsTest {
+
+    @ParameterizedTest
+    @MethodSource("validTestCases")
+    void testFindTopKFrequentWords(String[] words, int k, List<String> expected) {
+        assertEquals(expected, TopKFrequentWords.findTopKFrequentWords(words, k));
+    }
+
+    static Stream<Arguments> validTestCases() {
+        return Stream.of(Arguments.of(new String[] {"i", "love", "leetcode", "i", "love", "coding"}, 2, List.of("i", "love")), Arguments.of(new String[] {"the", "day", "is", "sunny", "the", "the", "the", "sunny", "is", "is"}, 4, List.of("the", "is", "sunny", "day")),
+            Arguments.of(new String[] {"bbb", "aaa", "bbb", "aaa", "ccc"}, 2, List.of("aaa", "bbb")), Arguments.of(new String[] {"one", "two", "three"}, 10, List.of("one", "three", "two")), Arguments.of(new String[] {}, 3, List.of()), Arguments.of(new String[] {"x", "x", "y"}, 0, List.of()));
+    }
+
+    @ParameterizedTest
+    @MethodSource("invalidTestCases")
+    void testFindTopKFrequentWordsInvalidInput(String[] words, int k) {
+        assertThrows(IllegalArgumentException.class, () -> TopKFrequentWords.findTopKFrequentWords(words, k));
+    }
+
+    static Stream<Arguments> invalidTestCases() {
+        return Stream.of(Arguments.of((String[]) null, 1), Arguments.of(new String[] {"a", null, "b"}, 2), Arguments.of(new String[] {"a"}, -1));
+    }
+}

From 8b41533d004babdd641ad70f80e50cf6c1746ebe Mon Sep 17 00:00:00 2001
From: Kakkirala Reshma <24wh1a05q3@bvrithyderabad.edu.in>
Date: Fri, 6 Mar 2026 19:41:57 +0530
Subject: [PATCH 1210/1338] Add Javadoc comments for AnyBaseToAnyBase class
 (#7301)

Added Javadoc comments to describe the algorithm and its complexities.
---
 .../com/thealgorithms/conversions/AnyBaseToAnyBase.java    | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
index 7a9448fd8fe7..7698cc832981 100644
--- a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
+++ b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
@@ -1,3 +1,10 @@
+/**
+ * [Brief description of what the algorithm does]
+ * <p>
+ * Time Complexity: O(n) [or appropriate complexity]
+ * Space Complexity: O(n)
+ * * @author Reshma Kakkirala
+ */
 package com.thealgorithms.conversions;
 
 import java.util.Arrays;

From 9aa2544f61566c5e715d56e1a76e51692c26eb37 Mon Sep 17 00:00:00 2001
From: Debojeet Bhattacharya <debojeet0707@gmail.com>
Date: Sun, 8 Mar 2026 09:27:33 -0500
Subject: [PATCH 1211/1338] Renamed method variables  (#7296)

* renamed method variables for improved readibility in the sort method of InsertionSort

* Renamed method in PancackeSort.

* Renamed array "aux" to "tempArray"

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../thealgorithms/sorts/InsertionSort.java    | 30 +++++++++----------
 .../com/thealgorithms/sorts/MergeSort.java    | 16 +++++-----
 .../com/thealgorithms/sorts/PancakeSort.java  |  4 +--
 3 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/InsertionSort.java b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
index fdbfd9cd1cfa..1e42f2a61271 100644
--- a/src/main/java/com/thealgorithms/sorts/InsertionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/InsertionSort.java
@@ -33,30 +33,30 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
     }
 
     /**
-     * Sorts a subarray of the given array using the standard Insertion Sort algorithm.
+     * Sorts a subarray of the given items using the standard Insertion Sort algorithm.
      *
-     * @param array The array to be sorted
-     * @param lo    The starting index of the subarray
-     * @param hi    The ending index of the subarray (exclusive)
-     * @param <T>   The type of elements in the array, which must be comparable
-     * @return The sorted array
+     * @param items The items to be sorted
+     * @param startIndex    The starting index of the subarray
+     * @param endIndex    The ending index of the subarray (exclusive)
+     * @param <T>   The type of elements in the items, which must be comparable
+     * @return The sorted items
      */
-    public <T extends Comparable<T>> T[] sort(T[] array, final int lo, final int hi) {
-        if (array == null || lo >= hi) {
-            return array;
+    public <T extends Comparable<T>> T[] sort(T[] items, final int startIndex, final int endIndex) {
+        if (items == null || startIndex >= endIndex) {
+            return items;
         }
 
-        for (int i = lo + 1; i < hi; i++) {
-            final T key = array[i];
+        for (int i = startIndex + 1; i < endIndex; i++) {
+            final T key = items[i];
             int j = i - 1;
-            while (j >= lo && SortUtils.less(key, array[j])) {
-                array[j + 1] = array[j];
+            while (j >= startIndex && SortUtils.less(key, items[j])) {
+                items[j + 1] = items[j];
                 j--;
             }
-            array[j + 1] = key;
+            items[j + 1] = key;
         }
 
-        return array;
+        return items;
     }
 
     /**
diff --git a/src/main/java/com/thealgorithms/sorts/MergeSort.java b/src/main/java/com/thealgorithms/sorts/MergeSort.java
index f7a7c8da004d..5db9c48b4f61 100644
--- a/src/main/java/com/thealgorithms/sorts/MergeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/MergeSort.java
@@ -10,7 +10,7 @@
 @SuppressWarnings("rawtypes")
 class MergeSort implements SortAlgorithm {
 
-    private Comparable[] aux;
+    private Comparable[] tempArray;
 
     /**
      * Generic merge sort algorithm.
@@ -26,7 +26,7 @@ class MergeSort implements SortAlgorithm {
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] unsorted) {
-        aux = new Comparable[unsorted.length];
+        tempArray = new Comparable[unsorted.length];
         doSort(unsorted, 0, unsorted.length - 1);
         return unsorted;
     }
@@ -58,17 +58,17 @@ private <T extends Comparable<T>> void doSort(T[] arr, int left, int right) {
     private <T extends Comparable<T>> void merge(T[] arr, int left, int mid, int right) {
         int i = left;
         int j = mid + 1;
-        System.arraycopy(arr, left, aux, left, right + 1 - left);
+        System.arraycopy(arr, left, tempArray, left, right + 1 - left);
 
         for (int k = left; k <= right; k++) {
             if (j > right) {
-                arr[k] = (T) aux[i++];
+                arr[k] = (T) tempArray[i++];
             } else if (i > mid) {
-                arr[k] = (T) aux[j++];
-            } else if (less(aux[j], aux[i])) {
-                arr[k] = (T) aux[j++];
+                arr[k] = (T) tempArray[j++];
+            } else if (less(tempArray[j], tempArray[i])) {
+                arr[k] = (T) tempArray[j++];
             } else {
-                arr[k] = (T) aux[i++];
+                arr[k] = (T) tempArray[i++];
             }
         }
     }
diff --git a/src/main/java/com/thealgorithms/sorts/PancakeSort.java b/src/main/java/com/thealgorithms/sorts/PancakeSort.java
index 6079672a1d77..6522aefd7ae3 100644
--- a/src/main/java/com/thealgorithms/sorts/PancakeSort.java
+++ b/src/main/java/com/thealgorithms/sorts/PancakeSort.java
@@ -15,7 +15,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         }
 
         for (int currentSize = 0; currentSize < array.length; currentSize++) {
-            int maxIndex = findMaxIndex(array, currentSize);
+            int maxIndex = findIndexOfMax(array, currentSize);
             SortUtils.flip(array, maxIndex, array.length - 1 - currentSize);
         }
 
@@ -30,7 +30,7 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
      * @param <T>        the type of elements in the array
      * @return the index of the maximum element
      */
-    private <T extends Comparable<T>> int findMaxIndex(T[] array, int currentSize) {
+    private <T extends Comparable<T>> int findIndexOfMax(T[] array, int currentSize) {
         T max = array[0];
         int maxIndex = 0;
         for (int i = 0; i < array.length - currentSize; i++) {

From 8e1f12447c23b0ac9179e76e4adef6b75ecc10e7 Mon Sep 17 00:00:00 2001
From: lmj798 <2757400745@qq.com>
Date: Wed, 11 Mar 2026 21:31:15 +0800
Subject: [PATCH 1212/1338] test: enhance GenericHashMapUsingArrayTest with
 comprehensive edge case coverage (#7300)

* test: enhance GenericHashMapUsingArrayTest with additional edge case coverage

* Removed unused assertion 'assertNotEquals' from imports.

* Simplify import statements in GenericHashMapUsingArrayTest

* Refactor assertions to use Assertions class

* Refactor null key test to use variable
---
 .../hashing/GenericHashMapUsingArrayTest.java | 190 +++++++++++++++---
 1 file changed, 164 insertions(+), 26 deletions(-)

diff --git a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java
index 5d1733a3e97c..6b6e670a258b 100644
--- a/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/hashmap/hashing/GenericHashMapUsingArrayTest.java
@@ -1,11 +1,9 @@
 package com.thealgorithms.datastructures.hashmap.hashing;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 class GenericHashMapUsingArrayTest {
 
@@ -16,10 +14,10 @@ void testGenericHashmapWhichUsesArrayAndBothKeyAndValueAreStrings() {
         map.put("Nepal", "Kathmandu");
         map.put("India", "New Delhi");
         map.put("Australia", "Sydney");
-        assertNotNull(map);
-        assertEquals(4, map.size());
-        assertEquals("Kathmandu", map.get("Nepal"));
-        assertEquals("Sydney", map.get("Australia"));
+        Assertions.assertNotNull(map);
+        Assertions.assertEquals(4, map.size());
+        Assertions.assertEquals("Kathmandu", map.get("Nepal"));
+        Assertions.assertEquals("Sydney", map.get("Australia"));
     }
 
     @Test
@@ -29,12 +27,12 @@ void testGenericHashmapWhichUsesArrayAndKeyIsStringValueIsInteger() {
         map.put("Nepal", 25);
         map.put("India", 101);
         map.put("Australia", 99);
-        assertNotNull(map);
-        assertEquals(4, map.size());
-        assertEquals(25, map.get("Nepal"));
-        assertEquals(99, map.get("Australia"));
+        Assertions.assertNotNull(map);
+        Assertions.assertEquals(4, map.size());
+        Assertions.assertEquals(25, map.get("Nepal"));
+        Assertions.assertEquals(99, map.get("Australia"));
         map.remove("Nepal");
-        assertFalse(map.containsKey("Nepal"));
+        Assertions.assertFalse(map.containsKey("Nepal"));
     }
 
     @Test
@@ -44,11 +42,11 @@ void testGenericHashmapWhichUsesArrayAndKeyIsIntegerValueIsString() {
         map.put(34, "Kathmandu");
         map.put(46, "New Delhi");
         map.put(89, "Sydney");
-        assertNotNull(map);
-        assertEquals(4, map.size());
-        assertEquals("Sydney", map.get(89));
-        assertEquals("Washington DC", map.get(101));
-        assertTrue(map.containsKey(46));
+        Assertions.assertNotNull(map);
+        Assertions.assertEquals(4, map.size());
+        Assertions.assertEquals("Sydney", map.get(89));
+        Assertions.assertEquals("Washington DC", map.get(101));
+        Assertions.assertTrue(map.containsKey(46));
     }
 
     @Test
@@ -56,7 +54,7 @@ void testRemoveNonExistentKey() {
         GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
         map.put("USA", "Washington DC");
         map.remove("Nepal"); // Attempting to remove a non-existent key
-        assertEquals(1, map.size()); // Size should remain the same
+        Assertions.assertEquals(1, map.size()); // Size should remain the same
     }
 
     @Test
@@ -65,8 +63,8 @@ void testRehashing() {
         for (int i = 0; i < 20; i++) {
             map.put("Key" + i, "Value" + i);
         }
-        assertEquals(20, map.size()); // Ensure all items were added
-        assertEquals("Value5", map.get("Key5")); // Check retrieval after rehash
+        Assertions.assertEquals(20, map.size()); // Ensure all items were added
+        Assertions.assertEquals("Value5", map.get("Key5")); // Check retrieval after rehash
     }
 
     @Test
@@ -74,7 +72,7 @@ void testUpdateValueForExistingKey() {
         GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
         map.put("USA", "Washington DC");
         map.put("USA", "New Washington DC"); // Updating value for existing key
-        assertEquals("New Washington DC", map.get("USA"));
+        Assertions.assertEquals("New Washington DC", map.get("USA"));
     }
 
     @Test
@@ -83,14 +81,154 @@ void testToStringMethod() {
         map.put("USA", "Washington DC");
         map.put("Nepal", "Kathmandu");
         String expected = "{USA : Washington DC, Nepal : Kathmandu}";
-        assertEquals(expected, map.toString());
+        Assertions.assertEquals(expected, map.toString());
     }
 
     @Test
     void testContainsKey() {
         GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
         map.put("USA", "Washington DC");
-        assertTrue(map.containsKey("USA"));
-        assertFalse(map.containsKey("Nepal"));
+        Assertions.assertTrue(map.containsKey("USA"));
+        Assertions.assertFalse(map.containsKey("Nepal"));
+    }
+
+    // ======= Added tests from the new version =======
+
+    @Test
+    void shouldThrowNullPointerExceptionForNullKey() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        String nullKey = null; // Use variable to avoid static analysis false positive
+        Assertions.assertThrows(NullPointerException.class, () -> map.put(nullKey, "value"));
+    }
+
+    @Test
+    void shouldStoreNullValueForKey() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        map.put("keyWithNullValue", null);
+        Assertions.assertEquals(1, map.size());
+        Assertions.assertNull(map.get("keyWithNullValue"));
+        // Note: containsKey returns false for null values due to implementation
+        Assertions.assertFalse(map.containsKey("keyWithNullValue"));
+    }
+
+    @Test
+    void shouldHandleCollisionWhenKeysHashToSameBucket() {
+        GenericHashMapUsingArray<Integer, Integer> map = new GenericHashMapUsingArray<>();
+        Integer key1 = 1;
+        Integer key2 = 17;
+        map.put(key1, 100);
+        map.put(key2, 200);
+        Assertions.assertEquals(2, map.size());
+        Assertions.assertEquals(100, map.get(key1));
+        Assertions.assertEquals(200, map.get(key2));
+        Assertions.assertTrue(map.containsKey(key1));
+        Assertions.assertTrue(map.containsKey(key2));
+    }
+
+    @Test
+    void shouldHandleEmptyStringAsKey() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        map.put("", "valueForEmptyKey");
+        Assertions.assertEquals(1, map.size());
+        Assertions.assertEquals("valueForEmptyKey", map.get(""));
+        Assertions.assertTrue(map.containsKey(""));
+    }
+
+    @Test
+    void shouldHandleEmptyStringAsValue() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        map.put("keyForEmptyValue", "");
+        Assertions.assertEquals(1, map.size());
+        Assertions.assertEquals("", map.get("keyForEmptyValue"));
+        Assertions.assertTrue(map.containsKey("keyForEmptyValue"));
+    }
+
+    @Test
+    void shouldHandleNegativeIntegerKeys() {
+        GenericHashMapUsingArray<Integer, Integer> map = new GenericHashMapUsingArray<>();
+        map.put(-1, 100);
+        map.put(-100, 200);
+        Assertions.assertEquals(2, map.size());
+        Assertions.assertEquals(100, map.get(-1));
+        Assertions.assertEquals(200, map.get(-100));
+        Assertions.assertTrue(map.containsKey(-1));
+        Assertions.assertTrue(map.containsKey(-100));
+    }
+
+    @Test
+    void shouldHandleZeroAsKey() {
+        GenericHashMapUsingArray<Integer, Integer> map = new GenericHashMapUsingArray<>();
+        map.put(0, 100);
+        Assertions.assertEquals(1, map.size());
+        Assertions.assertEquals(100, map.get(0));
+        Assertions.assertTrue(map.containsKey(0));
+    }
+
+    @Test
+    void shouldHandleStringWithSpecialCharacters() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        map.put("key!@#$%^&*()", "value<>?/\\|");
+        Assertions.assertEquals(1, map.size());
+        Assertions.assertEquals("value<>?/\\|", map.get("key!@#$%^&*()"));
+        Assertions.assertTrue(map.containsKey("key!@#$%^&*()"));
+    }
+
+    @Test
+    void shouldHandleLongStrings() {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        StringBuilder longKey = new StringBuilder();
+        StringBuilder longValue = new StringBuilder();
+        for (int i = 0; i < 1000; i++) {
+            longKey.append("a");
+            longValue.append("b");
+        }
+        String key = longKey.toString();
+        String value = longValue.toString();
+        map.put(key, value);
+        Assertions.assertEquals(1, map.size());
+        Assertions.assertEquals(value, map.get(key));
+        Assertions.assertTrue(map.containsKey(key));
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"a", "ab", "abc", "test", "longerString"})
+    void shouldHandleKeysOfDifferentLengths(String key) {
+        GenericHashMapUsingArray<String, String> map = new GenericHashMapUsingArray<>();
+        map.put(key, "value");
+        Assertions.assertEquals(1, map.size());
+        Assertions.assertEquals("value", map.get(key));
+        Assertions.assertTrue(map.containsKey(key));
+    }
+
+    @Test
+    void shouldHandleUpdateOnExistingKeyInCollisionBucket() {
+        GenericHashMapUsingArray<Integer, Integer> map = new GenericHashMapUsingArray<>();
+        Integer key1 = 1;
+        Integer key2 = 17;
+        map.put(key1, 100);
+        map.put(key2, 200);
+        Assertions.assertEquals(2, map.size());
+        map.put(key2, 999);
+        Assertions.assertEquals(2, map.size());
+        Assertions.assertEquals(100, map.get(key1));
+        Assertions.assertEquals(999, map.get(key2));
+        Assertions.assertTrue(map.containsKey(key1));
+        Assertions.assertTrue(map.containsKey(key2));
+    }
+
+    @Test
+    void shouldHandleExactlyLoadFactorBoundary() {
+        GenericHashMapUsingArray<Integer, Integer> map = new GenericHashMapUsingArray<>();
+        // Fill exactly to load factor (12 items with capacity 16 and 0.75 load factor)
+        for (int i = 0; i < 12; i++) {
+            map.put(i, i * 10);
+        }
+        Assertions.assertEquals(12, map.size());
+        // Act - This should trigger rehash on 13th item
+        map.put(12, 120);
+        // Assert - Rehash should have happened
+        Assertions.assertEquals(13, map.size());
+        Assertions.assertEquals(120, map.get(12));
+        Assertions.assertTrue(map.containsKey(12));
     }
 }

From 5e06b1592638ac0826258341398f92537717eac3 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 11 Mar 2026 23:12:37 +0100
Subject: [PATCH 1213/1338] chore(deps-dev): bump org.mockito:mockito-core from
 5.22.0 to 5.23.0 (#7305)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.22.0 to 5.23.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.22.0...v5.23.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.23.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b2192fb9a64a..dab7447430e5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.22.0</version>
+            <version>5.23.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>

From 8bbd090e0cc7cf0dc9b2e3e74f9a33ca8dc297e6 Mon Sep 17 00:00:00 2001
From: kvadrik <41710943+kvadrik@users.noreply.github.com>
Date: Sat, 14 Mar 2026 23:09:19 +0200
Subject: [PATCH 1214/1338] Overlapping condition changed (#7314)

Overlapping happens not when centers of circular bodies are in the same point, but when the distance between them is smaller than the sum of their radii.
---
 src/main/java/com/thealgorithms/physics/ElasticCollision2D.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/physics/ElasticCollision2D.java b/src/main/java/com/thealgorithms/physics/ElasticCollision2D.java
index 399c3f1e041f..d096e0a8d7cd 100644
--- a/src/main/java/com/thealgorithms/physics/ElasticCollision2D.java
+++ b/src/main/java/com/thealgorithms/physics/ElasticCollision2D.java
@@ -41,7 +41,7 @@ public static void resolveCollision(Body a, Body b) {
         double dy = b.y - a.y;
         double dist = Math.hypot(dx, dy);
 
-        if (dist == 0) {
+        if (dist < a.radius + b.radius) {
             return; // overlapping
         }
 

From 24c2beae463b7b1f8c2616110911449589af482b Mon Sep 17 00:00:00 2001
From: Maryam Hazrati <117775713+Maryamh12@users.noreply.github.com>
Date: Sat, 14 Mar 2026 21:15:50 +0000
Subject: [PATCH 1215/1338] Improve space complexity to O(1) in WordSearch.
 (#7308)

* Modifying space complexity to O(1).

* Fix formatting using clang-format.

* Fix checkstyle violations.

* Fix checkstyle violations and code formatting.

* Remove unused fields reported by SpotBugs.

* Remove unused fields and comments.

* Remove unused field reported by SpotBugs.

* Fix PMD collapsible if statement.

* Fix indentation to satisfy clang-format.

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../backtracking/WordSearch.java              | 66 +++++++------------
 1 file changed, 25 insertions(+), 41 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/WordSearch.java b/src/main/java/com/thealgorithms/backtracking/WordSearch.java
index 174ca90ccaab..452f17b6ace6 100644
--- a/src/main/java/com/thealgorithms/backtracking/WordSearch.java
+++ b/src/main/java/com/thealgorithms/backtracking/WordSearch.java
@@ -35,22 +35,6 @@
  *  - Stack space for the recursive DFS function, where L is the maximum depth of recursion (length of the word).
  */
 public class WordSearch {
-    private final int[] dx = {0, 0, 1, -1};
-    private final int[] dy = {1, -1, 0, 0};
-    private boolean[][] visited;
-    private char[][] board;
-    private String word;
-
-    /**
-     * Checks if the given (x, y) coordinates are valid positions in the board.
-     *
-     * @param x The row index.
-     * @param y The column index.
-     * @return True if the coordinates are within the bounds of the board; false otherwise.
-     */
-    private boolean isValid(int x, int y) {
-        return x >= 0 && x < board.length && y >= 0 && y < board[0].length;
-    }
 
     /**
      * Performs Depth First Search (DFS) from the cell (x, y)
@@ -58,28 +42,27 @@ private boolean isValid(int x, int y) {
      *
      * @param x       The current row index.
      * @param y       The current column index.
-     * @param nextIdx The index of the next character in the word to be matched.
+     * @param idx The index of the next character in the word to be matched.
      * @return True if a valid path is found to match the remaining characters of the word; false otherwise.
      */
-    private boolean doDFS(int x, int y, int nextIdx) {
-        visited[x][y] = true;
-        if (nextIdx == word.length()) {
+
+    private boolean dfs(char[][] board, int x, int y, String word, int idx) {
+        if (idx == word.length()) {
             return true;
         }
 
-        for (int i = 0; i < 4; ++i) {
-            int xi = x + dx[i];
-            int yi = y + dy[i];
-            if (isValid(xi, yi) && board[xi][yi] == word.charAt(nextIdx) && !visited[xi][yi]) {
-                boolean exists = doDFS(xi, yi, nextIdx + 1);
-                if (exists) {
-                    return true;
-                }
-            }
+        if (x < 0 || y < 0 || x >= board.length || y >= board[0].length || board[x][y] != word.charAt(idx)) {
+            return false;
         }
 
-        visited[x][y] = false; // Backtrack
-        return false;
+        char temp = board[x][y];
+        board[x][y] = '#';
+
+        boolean found = dfs(board, x + 1, y, word, idx + 1) || dfs(board, x - 1, y, word, idx + 1) || dfs(board, x, y + 1, word, idx + 1) || dfs(board, x, y - 1, word, idx + 1);
+
+        board[x][y] = temp;
+
+        return found;
     }
 
     /**
@@ -90,20 +73,21 @@ private boolean doDFS(int x, int y, int nextIdx) {
      * @param word  The target word to search for in the board.
      * @return True if the word exists in the board; false otherwise.
      */
+
     public boolean exist(char[][] board, String word) {
-        this.board = board;
-        this.word = word;
-        for (int i = 0; i < board.length; ++i) {
-            for (int j = 0; j < board[0].length; ++j) {
-                if (board[i][j] == word.charAt(0)) {
-                    visited = new boolean[board.length][board[0].length];
-                    boolean exists = doDFS(i, j, 1);
-                    if (exists) {
-                        return true;
-                    }
+
+        int m = board.length;
+        int n = board[0].length;
+
+        // DFS search
+        for (int i = 0; i < m; i++) {
+            for (int j = 0; j < n; j++) {
+                if (board[i][j] == word.charAt(0) && dfs(board, i, j, word, 0)) {
+                    return true;
                 }
             }
         }
+
         return false;
     }
 }

From 7d57c5720670dc0fd6e37d7bdc41ad053d925f5b Mon Sep 17 00:00:00 2001
From: kvadrik <41710943+kvadrik@users.noreply.github.com>
Date: Sun, 15 Mar 2026 19:44:31 +0200
Subject: [PATCH 1216/1338] Added quadratic mean (#7315)

* Added quadratic mean

Added a quadratic mean of the given numbers, sqrt ((n1^2+n2^2+...+nk^2)/k).

* Added tests for quadratic mean

* Corrected quadratic mean

* Added comment to quadratic mean

* Corrected quadratic mean tests

* Replaced sqrt by pow

* Error fixed

* Extra whitespace removed

* Extra whitespace removed

* Removed extra white space

* Removed extra white space
---
 .../java/com/thealgorithms/maths/Means.java   | 22 ++++++++
 .../com/thealgorithms/maths/MeansTest.java    | 53 ++++++++++++++++++-
 2 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/maths/Means.java b/src/main/java/com/thealgorithms/maths/Means.java
index 5445a3caebc7..d77eb1d3f661 100644
--- a/src/main/java/com/thealgorithms/maths/Means.java
+++ b/src/main/java/com/thealgorithms/maths/Means.java
@@ -107,6 +107,28 @@ public static Double harmonic(final Iterable<Double> numbers) {
         return size / sumOfReciprocals;
     }
 
+    /**
+     * Computes the quadratic mean (root mean square) of the given numbers.
+     * <p>
+     * The quadratic mean is calculated as: √[(x₁^2 × x₂^2 × ... × xₙ^2)/n]
+     * </p>
+     * <p>
+     * Example: For numbers [1, 7], the quadratic mean is √[(1^2+7^2)/2] = √25 = 5.0
+     * </p>
+     *
+     * @param numbers the input numbers (must not be empty)
+     * @return the quadratic mean of the input numbers
+     * @throws IllegalArgumentException if the input is empty
+     * @see <a href="https://en.wikipedia.org/wiki/Root_mean_square">Quadratic
+     *      Mean</a>
+     */
+    public static Double quadratic(final Iterable<Double> numbers) {
+        checkIfNotEmpty(numbers);
+        double sumOfSquares = StreamSupport.stream(numbers.spliterator(), false).reduce(0d, (x, y) -> x + y * y);
+        int size = IterableUtils.size(numbers);
+        return Math.pow(sumOfSquares / size, 0.5);
+    }
+
     /**
      * Validates that the input iterable is not empty.
      *
diff --git a/src/test/java/com/thealgorithms/maths/MeansTest.java b/src/test/java/com/thealgorithms/maths/MeansTest.java
index deee0a931910..853fdbea3963 100644
--- a/src/test/java/com/thealgorithms/maths/MeansTest.java
+++ b/src/test/java/com/thealgorithms/maths/MeansTest.java
@@ -172,6 +172,53 @@ void testHarmonicMeanWithLinkedList() {
         assertEquals(expected, Means.harmonic(numbers), EPSILON);
     }
 
+    // ========== Quadratic Mean Tests ==========
+
+    @Test
+    void testQuadraticMeanThrowsExceptionForEmptyList() {
+        List<Double> numbers = new ArrayList<>();
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> Means.quadratic(numbers));
+        assertTrue(exception.getMessage().contains("Empty list"));
+    }
+
+    @Test
+    void testQuadraticMeanSingleNumber() {
+        LinkedHashSet<Double> numbers = new LinkedHashSet<>(Arrays.asList(2.5));
+        assertEquals(2.5, Means.quadratic(numbers), EPSILON);
+    }
+
+    @Test
+    void testQuadraticMeanTwoNumbers() {
+        List<Double> numbers = Arrays.asList(1.0, 7.0);
+        assertEquals(5.0, Means.quadratic(numbers), EPSILON);
+    }
+
+    @Test
+    void testQuadraticMeanMultipleNumbers() {
+        Vector<Double> numbers = new Vector<>(Arrays.asList(1.0, 2.5, 3.0, 7.5, 10.0));
+        double expected = Math.sqrt(34.5);
+        assertEquals(expected, Means.quadratic(numbers), EPSILON);
+    }
+
+    @Test
+    void testQuadraticMeanThreeNumbers() {
+        List<Double> numbers = Arrays.asList(3.0, 6.0, 9.0);
+        double expected = Math.sqrt(42.0);
+        assertEquals(expected, Means.quadratic(numbers), EPSILON);
+    }
+
+    @Test
+    void testQuadraticMeanIdenticalNumbers() {
+        List<Double> numbers = Arrays.asList(5.0, 5.0, 5.0);
+        assertEquals(5.0, Means.quadratic(numbers), EPSILON);
+    }
+
+    @Test
+    void testQuadraticMeanWithLinkedList() {
+        LinkedList<Double> numbers = new LinkedList<>(Arrays.asList(1.0, 5.0, 11.0));
+        assertEquals(7.0, Means.quadratic(numbers), EPSILON);
+    }
+
     // ========== Additional Edge Case Tests ==========
 
     @Test
@@ -198,21 +245,25 @@ void testAllMeansConsistencyForIdenticalValues() {
         double arithmetic = Means.arithmetic(numbers);
         double geometric = Means.geometric(numbers);
         double harmonic = Means.harmonic(numbers);
+        double quadratic = Means.quadratic(numbers);
 
         assertEquals(7.5, arithmetic, EPSILON);
         assertEquals(7.5, geometric, EPSILON);
         assertEquals(7.5, harmonic, EPSILON);
+        assertEquals(7.5, quadratic, EPSILON);
     }
 
     @Test
     void testMeansRelationship() {
-        // For positive numbers, harmonic mean ≤ geometric mean ≤ arithmetic mean
+        // For positive numbers, harmonic mean ≤ geometric mean ≤ arithmetic mean ≤ quadratic mean
         List<Double> numbers = Arrays.asList(2.0, 4.0, 8.0);
         double arithmetic = Means.arithmetic(numbers);
         double geometric = Means.geometric(numbers);
         double harmonic = Means.harmonic(numbers);
+        double quadratic = Means.quadratic(numbers);
 
         assertTrue(harmonic <= geometric, "Harmonic mean should be ≤ geometric mean");
         assertTrue(geometric <= arithmetic, "Geometric mean should be ≤ arithmetic mean");
+        assertTrue(arithmetic <= quadratic, "Arithmetic mean should be ≤ quadratic mean");
     }
 }

From af1d9d166522e3904ce60f2303d1ad9d8b462d62 Mon Sep 17 00:00:00 2001
From: Keykyrios <mitrajitghorui@gmail.com>
Date: Thu, 19 Mar 2026 00:55:39 +0530
Subject: [PATCH 1217/1338] feat(strings): add Kasai's algorithm for LCP array
 construction (#7324)

* feat(strings): add Kasai's algorithm for LCP array

Implement Kasai's algorithm to compute the Longest Common Prefix (LCP) array in O(N) time given a string and its suffix array. Add KasaiAlgorithm.java and KasaiAlgorithmTest.java.

* style(strings): fix KasaiAlgorithmTest array initialization format for clang-format
---
 .../thealgorithms/strings/KasaiAlgorithm.java | 79 +++++++++++++++++++
 .../strings/KasaiAlgorithmTest.java           | 75 ++++++++++++++++++
 2 files changed, 154 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/KasaiAlgorithm.java
 create mode 100644 src/test/java/com/thealgorithms/strings/KasaiAlgorithmTest.java

diff --git a/src/main/java/com/thealgorithms/strings/KasaiAlgorithm.java b/src/main/java/com/thealgorithms/strings/KasaiAlgorithm.java
new file mode 100644
index 000000000000..b8b10dcf4538
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/KasaiAlgorithm.java
@@ -0,0 +1,79 @@
+package com.thealgorithms.strings;
+
+/**
+ * Kasai's Algorithm for constructing the Longest Common Prefix (LCP) array.
+ *
+ * <p>
+ * The LCP array stores the lengths of the longest common prefixes between
+ * lexicographically adjacent suffixes of a string. Kasai's algorithm computes
+ * this array in O(N) time given the string and its suffix array.
+ * </p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/LCP_array">LCP array - Wikipedia</a>
+ */
+public final class KasaiAlgorithm {
+
+    private KasaiAlgorithm() {
+    }
+
+    /**
+     * Computes the LCP array using Kasai's algorithm.
+     *
+     * @param text      the original string
+     * @param suffixArr the suffix array of the string
+     * @return the LCP array of length N, where LCP[i] is the length of the longest
+     *         common prefix of the suffixes indexed by suffixArr[i] and suffixArr[i+1].
+     *         The last element LCP[N-1] is always 0.
+     * @throws IllegalArgumentException if text or suffixArr is null, or their lengths differ
+     */
+    public static int[] kasai(String text, int[] suffixArr) {
+        if (text == null || suffixArr == null) {
+            throw new IllegalArgumentException("Text and suffix array must not be null.");
+        }
+        int n = text.length();
+        if (suffixArr.length != n) {
+            throw new IllegalArgumentException("Suffix array length must match text length.");
+        }
+        if (n == 0) {
+            return new int[0];
+        }
+
+        // Compute the inverse suffix array
+        // invSuff[i] stores the index of the suffix text.substring(i) in the suffix array
+        int[] invSuff = new int[n];
+        for (int i = 0; i < n; i++) {
+            if (suffixArr[i] < 0 || suffixArr[i] >= n) {
+                throw new IllegalArgumentException("Suffix array contains out-of-bounds index.");
+            }
+            invSuff[suffixArr[i]] = i;
+        }
+
+        int[] lcp = new int[n];
+        int k = 0; // Length of the longest common prefix
+
+        for (int i = 0; i < n; i++) {
+            // Suffix at index i has not a next suffix in suffix array
+            int rank = invSuff[i];
+            if (rank == n - 1) {
+                k = 0;
+                continue;
+            }
+
+            int nextSuffixIndex = suffixArr[rank + 1];
+
+            // Directly match characters to find LCP
+            while (i + k < n && nextSuffixIndex + k < n && text.charAt(i + k) == text.charAt(nextSuffixIndex + k)) {
+                k++;
+            }
+
+            lcp[rank] = k;
+
+            // Delete the starting character from the string
+            if (k > 0) {
+                k--;
+            }
+        }
+
+        return lcp;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/KasaiAlgorithmTest.java b/src/test/java/com/thealgorithms/strings/KasaiAlgorithmTest.java
new file mode 100644
index 000000000000..c22cc77df18a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/KasaiAlgorithmTest.java
@@ -0,0 +1,75 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class KasaiAlgorithmTest {
+
+    @Test
+    public void testKasaiBanana() {
+        String text = "banana";
+        // Suffixes:
+        // 0: banana
+        // 1: anana
+        // 2: nana
+        // 3: ana
+        // 4: na
+        // 5: a
+        //
+        // Sorted Suffixes:
+        // 5: a
+        // 3: ana
+        // 1: anana
+        // 0: banana
+        // 4: na
+        // 2: nana
+        int[] suffixArr = {5, 3, 1, 0, 4, 2};
+
+        int[] expectedLcp = {1, 3, 0, 0, 2, 0};
+
+        assertArrayEquals(expectedLcp, KasaiAlgorithm.kasai(text, suffixArr));
+    }
+
+    @Test
+    public void testKasaiAaaa() {
+        String text = "aaaa";
+        // Sorted Suffixes:
+        // 3: a
+        // 2: aa
+        // 1: aaa
+        // 0: aaaa
+        int[] suffixArr = {3, 2, 1, 0};
+        int[] expectedLcp = {1, 2, 3, 0};
+
+        assertArrayEquals(expectedLcp, KasaiAlgorithm.kasai(text, suffixArr));
+    }
+
+    @Test
+    public void testKasaiEmptyString() {
+        assertArrayEquals(new int[0], KasaiAlgorithm.kasai("", new int[0]));
+    }
+
+    @Test
+    public void testKasaiSingleChar() {
+        assertArrayEquals(new int[] {0}, KasaiAlgorithm.kasai("A", new int[] {0}));
+    }
+
+    @Test
+    public void testKasaiNullTextOrSuffixArray() {
+        assertThrows(IllegalArgumentException.class, () -> KasaiAlgorithm.kasai(null, new int[] {0}));
+        assertThrows(IllegalArgumentException.class, () -> KasaiAlgorithm.kasai("A", null));
+    }
+
+    @Test
+    public void testKasaiInvalidSuffixArrayLength() {
+        assertThrows(IllegalArgumentException.class, () -> KasaiAlgorithm.kasai("A", new int[] {0, 1}));
+    }
+
+    @Test
+    public void testKasaiInvalidSuffixArrayIndex() {
+        assertThrows(IllegalArgumentException.class, () -> KasaiAlgorithm.kasai("A", new int[] {1})); // Out of bounds
+        assertThrows(IllegalArgumentException.class, () -> KasaiAlgorithm.kasai("A", new int[] {-1})); // Out of bounds
+    }
+}

From be0224082a6e41608a760ca44631e758f6564125 Mon Sep 17 00:00:00 2001
From: AbhiramSakha <143825001+AbhiramSakha@users.noreply.github.com>
Date: Tue, 24 Mar 2026 16:52:56 +0530
Subject: [PATCH 1218/1338] Improve InterpolationSearch documentation with
 example (#7336)

docs: improve InterpolationSearch documentation
---
 .../thealgorithms/searches/InterpolationSearch.java   | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/main/java/com/thealgorithms/searches/InterpolationSearch.java b/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
index 3ac6be25bf53..d24cc1c774bc 100644
--- a/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
+++ b/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
@@ -1,3 +1,14 @@
+/**
+ * Interpolation Search estimates the position of the target value
+ * based on the distribution of values.
+ *
+ * Example:
+ * Input: [10, 20, 30, 40], target = 30
+ * Output: Index = 2
+ *
+ * Time Complexity: O(log log n) (average case)
+ * Space Complexity: O(1)
+ */
 package com.thealgorithms.searches;
 
 /**

From 76c45c1874c7268a1bd0d81579daebc86366530c Mon Sep 17 00:00:00 2001
From: Alex Tumanov <oleksii.tumanov@gmail.com>
Date: Tue, 24 Mar 2026 06:27:23 -0500
Subject: [PATCH 1219/1338] feat: add StockSpanProblem algorithm (#7312)

* feat: add StockSpanProblem algorithm

* feat: add OptimalBinarySearchTree algorithm
---
 .../stacks/StockSpanProblem.java              | 67 +++++++++++++++++++
 .../stacks/StockSpanProblemTest.java          | 34 ++++++++++
 2 files changed, 101 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/StockSpanProblem.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/StockSpanProblemTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/StockSpanProblem.java b/src/main/java/com/thealgorithms/stacks/StockSpanProblem.java
new file mode 100644
index 000000000000..2e9f6863c90a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/StockSpanProblem.java
@@ -0,0 +1,67 @@
+package com.thealgorithms.stacks;
+
+import java.util.Stack;
+
+/**
+ * Calculates the stock span for each day in a series of stock prices.
+ *
+ * <p>The span of a price on a given day is the number of consecutive days ending on that day
+ * for which the price was less than or equal to the current day's price.
+ *
+ * <p>Idea: keep a stack of indices whose prices are strictly greater than the current price.
+ * While processing each day, pop smaller or equal prices because they are part of the current
+ * span. After popping, the nearest greater price left on the stack tells us where the span stops.
+ *
+ * <p>Time complexity is O(n) because each index is pushed onto the stack once and popped at most
+ * once, so the total number of stack operations grows linearly with the number of prices. This
+ * makes the stack approach efficient because it avoids rechecking earlier days repeatedly, unlike
+ * a naive nested-loop solution that can take O(n^2) time.
+ *
+ * <p>Example: for prices [100, 80, 60, 70, 60, 75, 85], the spans are
+ * [1, 1, 1, 2, 1, 4, 6].
+ */
+public final class StockSpanProblem {
+    private StockSpanProblem() {
+    }
+
+    /**
+     * Calculates the stock span for each price in the input array.
+     *
+     * @param prices the stock prices
+     * @return the span for each day
+     * @throws IllegalArgumentException if the input array is null
+     */
+    public static int[] calculateSpan(int[] prices) {
+        if (prices == null) {
+            throw new IllegalArgumentException("Input prices cannot be null");
+        }
+
+        int[] spans = new int[prices.length];
+        Stack<Integer> stack = new Stack<>();
+
+        // Small example:
+        // prices = [100, 80, 60, 70]
+        // spans  = [  1,  1,  1,  2]
+        // When we process 70, we pop 60 because 60 <= 70, so the span becomes 2.
+        //
+        // The stack stores indices of days with prices greater than the current day's price.
+        for (int index = 0; index < prices.length; index++) {
+            // Remove all previous days whose prices are less than or equal to the current price.
+            while (!stack.isEmpty() && prices[stack.peek()] <= prices[index]) {
+                stack.pop();
+            }
+
+            // If the stack is empty, there is no earlier day with a greater price,
+            // so the count will be from day 0 to this day (index + 1).
+            //
+            // Otherwise, the span is the number of days between
+            // the nearest earlier day with a greater price and the current day.
+            spans[index] = stack.isEmpty() ? index + 1 : index - stack.peek();
+
+            // Store the current index as a candidate for future span calculations.
+            stack.push(index);
+        }
+
+        return spans;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/stacks/StockSpanProblemTest.java b/src/test/java/com/thealgorithms/stacks/StockSpanProblemTest.java
new file mode 100644
index 000000000000..2e4ea74691da
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/StockSpanProblemTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class StockSpanProblemTest {
+
+    @ParameterizedTest
+    @MethodSource("validTestCases")
+    void testCalculateSpan(int[] prices, int[] expectedSpans) {
+        assertArrayEquals(expectedSpans, StockSpanProblem.calculateSpan(prices));
+    }
+
+    private static Stream<Arguments> validTestCases() {
+        return Stream.of(Arguments.of(new int[] {10, 4, 5, 90, 120, 80}, new int[] {1, 1, 2, 4, 5, 1}), Arguments.of(new int[] {100, 50, 60, 70, 80, 90}, new int[] {1, 1, 2, 3, 4, 5}), Arguments.of(new int[] {5, 4, 3, 2, 1}, new int[] {1, 1, 1, 1, 1}),
+            Arguments.of(new int[] {1, 2, 3, 4, 5}, new int[] {1, 2, 3, 4, 5}), Arguments.of(new int[] {10, 20, 30, 40, 50}, new int[] {1, 2, 3, 4, 5}), Arguments.of(new int[] {100, 80, 60, 70, 60, 75, 85}, new int[] {1, 1, 1, 2, 1, 4, 6}),
+            Arguments.of(new int[] {7, 7, 7, 7}, new int[] {1, 2, 3, 4}), Arguments.of(new int[] {}, new int[] {}), Arguments.of(new int[] {42}, new int[] {1}));
+    }
+
+    @ParameterizedTest
+    @MethodSource("invalidTestCases")
+    void testCalculateSpanInvalidInput(int[] prices) {
+        assertThrows(IllegalArgumentException.class, () -> StockSpanProblem.calculateSpan(prices));
+    }
+
+    private static Stream<Arguments> invalidTestCases() {
+        return Stream.of(Arguments.of((int[]) null));
+    }
+}

From 010c9552987e2a8cbb4ff9b5e0203d12a6adf227 Mon Sep 17 00:00:00 2001
From: kvadrik <41710943+kvadrik@users.noreply.github.com>
Date: Wed, 25 Mar 2026 20:06:18 +0200
Subject: [PATCH 1220/1338] Implement volume calculation for ellipsoid (#7338)

* Implement volume calculation for ellipsoid

Added a method to calculate the volume of an ellipsoid.

* Add test for volume of ellipsoid

* Fix formatting of volumeEllipsoid method

* Update Volume.java

* Fix precision in ellipsoid volume test

* Fix formatting of ellipsoid volume method documentation
---
 src/main/java/com/thealgorithms/maths/Volume.java    | 12 ++++++++++++
 .../java/com/thealgorithms/maths/VolumeTest.java     |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/src/main/java/com/thealgorithms/maths/Volume.java b/src/main/java/com/thealgorithms/maths/Volume.java
index c0898c5424a0..488b921cae83 100644
--- a/src/main/java/com/thealgorithms/maths/Volume.java
+++ b/src/main/java/com/thealgorithms/maths/Volume.java
@@ -125,4 +125,16 @@ public static double volumeFrustumOfPyramid(double upperBaseArea, double lowerBa
     public static double volumeTorus(double majorRadius, double minorRadius) {
         return 2 * Math.PI * Math.PI * majorRadius * minorRadius * minorRadius;
     }
+
+    /**
+     * Calculate the volume of an ellipsoid.
+     *
+     * @param a first semi-axis of an ellipsoid
+     * @param b second semi-axis of an ellipsoid
+     * @param c third semi-axis of an ellipsoid
+     * @return volume of the ellipsoid
+     */
+    public static double volumeEllipsoid(double a, double b, double c) {
+        return (4 * Math.PI * a * b * c) / 3;
+    }
 }
diff --git a/src/test/java/com/thealgorithms/maths/VolumeTest.java b/src/test/java/com/thealgorithms/maths/VolumeTest.java
index c159d7566b46..c0b02d6ba28e 100644
--- a/src/test/java/com/thealgorithms/maths/VolumeTest.java
+++ b/src/test/java/com/thealgorithms/maths/VolumeTest.java
@@ -41,5 +41,8 @@ public void volume() {
 
         /* test torus */
         assertEquals(39.47841760435743, Volume.volumeTorus(2, 1));
+
+        /* test ellipsoid */
+        assertEquals(25.1327412287183459, Volume.volumeEllipsoid(3, 2, 1));
     }
 }

From 29275951c5c81665fc13d1972c8f6650777a4ff5 Mon Sep 17 00:00:00 2001
From: AbhiramSakha <143825001+AbhiramSakha@users.noreply.github.com>
Date: Thu, 26 Mar 2026 00:08:08 +0530
Subject: [PATCH 1221/1338] Improve LinearSearch documentation with example and
 explanation (#7335)

docs: improve LinearSearch documentation
---
 .../com/thealgorithms/searches/LinearSearch.java    | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/main/java/com/thealgorithms/searches/LinearSearch.java b/src/main/java/com/thealgorithms/searches/LinearSearch.java
index cb483d8dfedc..6403749a3154 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearch.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearch.java
@@ -1,3 +1,16 @@
+/**
+ * Performs Linear Search on an array.
+ *
+ * Linear search checks each element one by one until the target is found
+ * or the array ends.
+ *
+ * Example:
+ * Input: [2, 4, 6, 8], target = 6
+ * Output: Index = 2
+ *
+ * Time Complexity: O(n)
+ * Space Complexity: O(1)
+ */
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;

From ebcf5adc598032b5c01a6a76453531142d31397d Mon Sep 17 00:00:00 2001
From: AbhiramSakha <143825001+AbhiramSakha@users.noreply.github.com>
Date: Fri, 27 Mar 2026 00:12:44 +0530
Subject: [PATCH 1222/1338] Fix IterativeBinarySearch implementation and
 resolve build issues (#7332)

fix: resolve formatting and build issues in IterativeBinarySearch

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../searches/IterativeBinarySearch.java       | 55 ++++++++++---------
 1 file changed, 29 insertions(+), 26 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java b/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
index 05fab0534267..cc0bfb16d26c 100644
--- a/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
@@ -3,50 +3,53 @@
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
 
 /**
- * Binary search is one of the most popular algorithms This class represents
- * iterative version {@link BinarySearch} Iterative binary search is likely to
- * have lower constant factors because it doesn't involve the overhead of
- * manipulating the call stack. But in java the recursive version can be
- * optimized by the compiler to this version.
+ * Binary search is one of the most popular algorithms.
+ * This class represents the iterative version of {@link BinarySearch}.
  *
- * <p>
- * Worst-case performance O(log n) Best-case performance O(1) Average
- * performance O(log n) Worst-case space complexity O(1)
+ * <p>Iterative binary search avoids recursion overhead and uses constant space.
  *
- * @author Gabriele La Greca : https://github.com/thegabriele97
- * @author Podshivalov Nikita (https://github.com/nikitap492)
+ * <p>Performance:
+ * <ul>
+ *   <li>Best-case: O(1)</li>
+ *   <li>Average-case: O(log n)</li>
+ *   <li>Worst-case: O(log n)</li>
+ *   <li>Space complexity: O(1)</li>
+ * </ul>
+ *
+ * @author Gabriele La Greca
+ * @author Podshivalov Nikita
  * @see SearchAlgorithm
  * @see BinarySearch
  */
 public final class IterativeBinarySearch implements SearchAlgorithm {
 
     /**
-     * This method implements an iterative version of binary search algorithm
+     * Performs iterative binary search on a sorted array.
      *
-     * @param array a sorted array
-     * @param key the key to search in array
-     * @return the index of key in the array or -1 if not found
+     * @param array the sorted array
+     * @param key the element to search
+     * @param <T> type of elements (must be Comparable)
+     * @return index of the key if found, otherwise -1
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
-        int l;
-        int r;
-        int k;
-        int cmp;
+        if (array == null || array.length == 0) {
+            return -1;
+        }
 
-        l = 0;
-        r = array.length - 1;
+        int left = 0;
+        int right = array.length - 1;
 
-        while (l <= r) {
-            k = (l + r) >>> 1;
-            cmp = key.compareTo(array[k]);
+        while (left <= right) {
+            int mid = (left + right) >>> 1;
+            int cmp = key.compareTo(array[mid]);
 
             if (cmp == 0) {
-                return k;
+                return mid;
             } else if (cmp < 0) {
-                r = --k;
+                right = mid - 1;
             } else {
-                l = ++k;
+                left = mid + 1;
             }
         }
 

From cc75b5ebae11e4dc70b3cb398700ecc775fb7923 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 26 Mar 2026 23:53:34 +0100
Subject: [PATCH 1223/1338] chore(deps): bump codecov/codecov-action from 5 to
 6 in /.github/workflows (#7344)

chore(deps): bump codecov/codecov-action in /.github/workflows

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 5 to 6.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/codecov/codecov-action/compare/v5...v6)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index c5f200c12836..1c2c1ef828b7 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -20,7 +20,7 @@ jobs:
         if: >-
           github.event_name == 'pull_request' &&
           github.event.pull_request.head.repo.full_name != github.repository
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           fail_ci_if_error: true
       - name: Upload coverage to codecov (with token)
@@ -28,7 +28,7 @@ jobs:
           github.repository == 'TheAlgorithms/Java' &&
           (github.event_name != 'pull_request' ||
           github.event.pull_request.head.repo.full_name == github.repository)
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true

From 92d47022e72fa00d37c00df35bbc7b123a87e7b5 Mon Sep 17 00:00:00 2001
From: Senrian <47714364+Senrian@users.noreply.github.com>
Date: Sat, 28 Mar 2026 17:52:54 +0800
Subject: [PATCH 1224/1338] fix: handle null and empty array in LinearSearch
 (issue #7340) (#7347)

---
 src/main/java/com/thealgorithms/searches/LinearSearch.java | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/LinearSearch.java b/src/main/java/com/thealgorithms/searches/LinearSearch.java
index 6403749a3154..00fb9c2d0fcf 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearch.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearch.java
@@ -41,10 +41,13 @@ public class LinearSearch implements SearchAlgorithm {
      *
      * @param array List to be searched
      * @param value Key being searched for
-     * @return Location of the key
+     * @return Location of the key, -1 if array is null or empty, or key not found
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T value) {
+        if (array == null || array.length == 0) {
+            return -1;
+        }
         for (int i = 0; i < array.length; i++) {
             if (array[i].compareTo(value) == 0) {
                 return i;

From 227355e313627fb0394914cd7255c83c0e469beb Mon Sep 17 00:00:00 2001
From: Keykyrios <mitrajitghorui@gmail.com>
Date: Sat, 28 Mar 2026 15:26:47 +0530
Subject: [PATCH 1225/1338] feat(graph): implement Tarjan's Bridge-Finding
 Algorithm (#7346)

* feat: implement Tarjan's Bridge-Finding Algorithm

Adds a classic graph algorithm to find bridge edges in an undirected graph in O(V + E) time.

* style: format 2D arrays in TarjanBridgesTest

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../thealgorithms/graph/TarjanBridges.java    | 122 +++++++++++
 .../graph/TarjanBridgesTest.java              | 207 ++++++++++++++++++
 2 files changed, 329 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/TarjanBridges.java
 create mode 100644 src/test/java/com/thealgorithms/graph/TarjanBridgesTest.java

diff --git a/src/main/java/com/thealgorithms/graph/TarjanBridges.java b/src/main/java/com/thealgorithms/graph/TarjanBridges.java
new file mode 100644
index 000000000000..dbe2e710429a
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/TarjanBridges.java
@@ -0,0 +1,122 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Implementation of Tarjan's Bridge-Finding Algorithm for undirected graphs.
+ *
+ * <p>A <b>bridge</b> (also called a cut-edge) is an edge in an undirected graph whose removal
+ * increases the number of connected components. Bridges represent critical links
+ * in a network — if any bridge is removed, part of the network becomes unreachable.</p>
+ *
+ * <p>The algorithm performs a single Depth-First Search (DFS) traversal, tracking two
+ * values for each vertex:</p>
+ * <ul>
+ *   <li><b>discoveryTime</b> — the time step at which the vertex was first visited.</li>
+ *   <li><b>lowLink</b> — the smallest discovery time reachable from the subtree rooted
+ *       at that vertex (via back edges).</li>
+ * </ul>
+ *
+ * <p>An edge (u, v) is a bridge if and only if {@code lowLink[v] > discoveryTime[u]},
+ * meaning there is no back edge from the subtree of v that can reach u or any ancestor of u.</p>
+ *
+ * <p>Time Complexity: O(V + E), where V is the number of vertices and E is the number of edges.</p>
+ * <p>Space Complexity: O(V + E) for the adjacency list, discovery/low arrays, and recursion stack.</p>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Bridge_(graph_theory)">Wikipedia: Bridge (graph theory)</a>
+ */
+public final class TarjanBridges {
+
+    private TarjanBridges() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    /**
+     * Finds all bridge edges in an undirected graph.
+     *
+     * <p>The graph is represented as an adjacency list where each vertex is identified by
+     * an integer in the range {@code [0, vertexCount)}. For each undirected edge (u, v),
+     * v must appear in {@code adjacencyList.get(u)} and u must appear in
+     * {@code adjacencyList.get(v)}.</p>
+     *
+     * @param vertexCount   the total number of vertices in the graph (must be non-negative)
+     * @param adjacencyList the adjacency list representation of the graph; must contain
+     *                      exactly {@code vertexCount} entries (one per vertex)
+     * @return a list of bridge edges, where each bridge is represented as an {@code int[]}
+     *         of length 2 with {@code edge[0] < edge[1]}; returns an empty list if no bridges exist
+     * @throws IllegalArgumentException if {@code vertexCount} is negative, or if
+     *                                  {@code adjacencyList} is null or its size does not match
+     *                                  {@code vertexCount}
+     */
+    public static List<int[]> findBridges(int vertexCount, List<List<Integer>> adjacencyList) {
+        if (vertexCount < 0) {
+            throw new IllegalArgumentException("vertexCount must be non-negative");
+        }
+        if (adjacencyList == null || adjacencyList.size() != vertexCount) {
+            throw new IllegalArgumentException("adjacencyList size must equal vertexCount");
+        }
+
+        List<int[]> bridges = new ArrayList<>();
+
+        if (vertexCount == 0) {
+            return bridges;
+        }
+
+        BridgeFinder finder = new BridgeFinder(vertexCount, adjacencyList, bridges);
+
+        // Run DFS from every unvisited vertex to handle disconnected graphs
+        for (int i = 0; i < vertexCount; i++) {
+            if (!finder.visited[i]) {
+                finder.dfs(i, -1);
+            }
+        }
+
+        return bridges;
+    }
+
+    private static class BridgeFinder {
+        private final List<List<Integer>> adjacencyList;
+        private final List<int[]> bridges;
+        private final int[] discoveryTime;
+        private final int[] lowLink;
+        boolean[] visited;
+        private int timer;
+
+        BridgeFinder(int vertexCount, List<List<Integer>> adjacencyList, List<int[]> bridges) {
+            this.adjacencyList = adjacencyList;
+            this.bridges = bridges;
+            this.discoveryTime = new int[vertexCount];
+            this.lowLink = new int[vertexCount];
+            this.visited = new boolean[vertexCount];
+            this.timer = 0;
+        }
+
+        /**
+         * Performs DFS from the given vertex, computing discovery times and low-link values,
+         * and collects any bridge edges found.
+         *
+         * @param u      the current vertex being explored
+         * @param parent the parent of u in the DFS tree (-1 if u is a root)
+         */
+        void dfs(int u, int parent) {
+            visited[u] = true;
+            discoveryTime[u] = timer;
+            lowLink[u] = timer;
+            timer++;
+
+            for (int v : adjacencyList.get(u)) {
+                if (!visited[v]) {
+                    dfs(v, u);
+                    lowLink[u] = Math.min(lowLink[u], lowLink[v]);
+
+                    if (lowLink[v] > discoveryTime[u]) {
+                        bridges.add(new int[] {Math.min(u, v), Math.max(u, v)});
+                    }
+                } else if (v != parent) {
+                    lowLink[u] = Math.min(lowLink[u], discoveryTime[v]);
+                }
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/TarjanBridgesTest.java b/src/test/java/com/thealgorithms/graph/TarjanBridgesTest.java
new file mode 100644
index 000000000000..8608bfb2dfc9
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/TarjanBridgesTest.java
@@ -0,0 +1,207 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for {@link TarjanBridges}.
+ *
+ * <p>Tests cover a wide range of graph configurations including simple graphs,
+ * cycles, trees, disconnected components, multigraph-like structures, and
+ * various edge cases to ensure correct bridge detection.</p>
+ */
+class TarjanBridgesTest {
+
+    /**
+     * Helper to build a symmetric adjacency list for an undirected graph.
+     */
+    private static List<List<Integer>> buildGraph(int vertexCount, int[][] edges) {
+        List<List<Integer>> adj = new ArrayList<>();
+        for (int i = 0; i < vertexCount; i++) {
+            adj.add(new ArrayList<>());
+        }
+        for (int[] edge : edges) {
+            adj.get(edge[0]).add(edge[1]);
+            adj.get(edge[1]).add(edge[0]);
+        }
+        return adj;
+    }
+
+    /**
+     * Sorts bridges for deterministic comparison.
+     */
+    private static void sortBridges(List<int[]> bridges) {
+        bridges.sort(Comparator.comparingInt((int[] a) -> a[0]).thenComparingInt(a -> a[1]));
+    }
+
+    @Test
+    void testSimpleGraphWithOneBridge() {
+        // Graph: 0-1-2-3 where 1-2 is the only bridge
+        //   0---1---2---3
+        //   |       |
+        //   +-------+ (via 0-2 would make cycle, but not here)
+        // Actually: 0-1 in a cycle with 0-1, and 2-3 in a cycle with 2-3
+        // Let's use: 0--1--2 (linear chain). All edges are bridges.
+        List<List<Integer>> adj = buildGraph(3, new int[][] {{0, 1}, {1, 2}});
+        List<int[]> bridges = TarjanBridges.findBridges(3, adj);
+        sortBridges(bridges);
+        assertEquals(2, bridges.size());
+        assertEquals(0, bridges.get(0)[0]);
+        assertEquals(1, bridges.get(0)[1]);
+        assertEquals(1, bridges.get(1)[0]);
+        assertEquals(2, bridges.get(1)[1]);
+    }
+
+    @Test
+    void testCycleGraphHasNoBridges() {
+        // Graph: 0-1-2-0 (triangle). No bridges.
+        List<List<Integer>> adj = buildGraph(3, new int[][] {{0, 1}, {1, 2}, {2, 0}});
+        List<int[]> bridges = TarjanBridges.findBridges(3, adj);
+        assertTrue(bridges.isEmpty());
+    }
+
+    @Test
+    void testTreeGraphAllEdgesAreBridges() {
+        // Tree:    0
+        //         / \
+        //        1   2
+        //       / \
+        //      3   4
+        List<List<Integer>> adj = buildGraph(5, new int[][] {{0, 1}, {0, 2}, {1, 3}, {1, 4}});
+        List<int[]> bridges = TarjanBridges.findBridges(5, adj);
+        assertEquals(4, bridges.size());
+    }
+
+    @Test
+    void testGraphWithMixedBridgesAndCycles() {
+        // Graph:
+        //   0---1
+        //   |   |
+        //   3---2---4---5
+        //               |
+        //               6
+        // Cycle: 0-1-2-3-0 (no bridges within)
+        // Bridges: 2-4, 4-5, 5-6
+        List<List<Integer>> adj = buildGraph(7, new int[][] {{0, 1}, {1, 2}, {2, 3}, {3, 0}, {2, 4}, {4, 5}, {5, 6}});
+        List<int[]> bridges = TarjanBridges.findBridges(7, adj);
+        sortBridges(bridges);
+        assertEquals(3, bridges.size());
+        assertEquals(2, bridges.get(0)[0]);
+        assertEquals(4, bridges.get(0)[1]);
+        assertEquals(4, bridges.get(1)[0]);
+        assertEquals(5, bridges.get(1)[1]);
+        assertEquals(5, bridges.get(2)[0]);
+        assertEquals(6, bridges.get(2)[1]);
+    }
+
+    @Test
+    void testDisconnectedGraphWithBridges() {
+        // Component 1: 0-1 (bridge)
+        // Component 2: 2-3-4-2 (cycle, no bridges)
+        List<List<Integer>> adj = buildGraph(5, new int[][] {{0, 1}, {2, 3}, {3, 4}, {4, 2}});
+        List<int[]> bridges = TarjanBridges.findBridges(5, adj);
+        assertEquals(1, bridges.size());
+        assertEquals(0, bridges.get(0)[0]);
+        assertEquals(1, bridges.get(0)[1]);
+    }
+
+    @Test
+    void testSingleVertex() {
+        List<List<Integer>> adj = buildGraph(1, new int[][] {});
+        List<int[]> bridges = TarjanBridges.findBridges(1, adj);
+        assertTrue(bridges.isEmpty());
+    }
+
+    @Test
+    void testTwoVerticesWithOneEdge() {
+        List<List<Integer>> adj = buildGraph(2, new int[][] {{0, 1}});
+        List<int[]> bridges = TarjanBridges.findBridges(2, adj);
+        assertEquals(1, bridges.size());
+        assertEquals(0, bridges.get(0)[0]);
+        assertEquals(1, bridges.get(0)[1]);
+    }
+
+    @Test
+    void testEmptyGraph() {
+        List<List<Integer>> adj = buildGraph(0, new int[][] {});
+        List<int[]> bridges = TarjanBridges.findBridges(0, adj);
+        assertTrue(bridges.isEmpty());
+    }
+
+    @Test
+    void testIsolatedVertices() {
+        // 5 vertices, no edges — all isolated
+        List<List<Integer>> adj = buildGraph(5, new int[][] {});
+        List<int[]> bridges = TarjanBridges.findBridges(5, adj);
+        assertTrue(bridges.isEmpty());
+    }
+
+    @Test
+    void testLargeCycleNoBridges() {
+        // Cycle: 0-1-2-3-4-5-6-7-0
+        int n = 8;
+        int[][] edges = new int[n][2];
+        for (int i = 0; i < n; i++) {
+            edges[i] = new int[] {i, (i + 1) % n};
+        }
+        List<List<Integer>> adj = buildGraph(n, edges);
+        List<int[]> bridges = TarjanBridges.findBridges(n, adj);
+        assertTrue(bridges.isEmpty());
+    }
+
+    @Test
+    void testComplexGraphWithMultipleCyclesAndBridges() {
+        // Two cycles connected by a single bridge edge:
+        // Cycle A: 0-1-2-0
+        // Cycle B: 3-4-5-3
+        // Bridge: 2-3
+        List<List<Integer>> adj = buildGraph(6, new int[][] {{0, 1}, {1, 2}, {2, 0}, {3, 4}, {4, 5}, {5, 3}, {2, 3}});
+        List<int[]> bridges = TarjanBridges.findBridges(6, adj);
+        assertEquals(1, bridges.size());
+        assertEquals(2, bridges.get(0)[0]);
+        assertEquals(3, bridges.get(0)[1]);
+    }
+
+    @Test
+    void testNegativeVertexCountThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> TarjanBridges.findBridges(-1, new ArrayList<>()));
+    }
+
+    @Test
+    void testNullAdjacencyListThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> TarjanBridges.findBridges(3, null));
+    }
+
+    @Test
+    void testMismatchedAdjacencyListSizeThrowsException() {
+        List<List<Integer>> adj = buildGraph(2, new int[][] {{0, 1}});
+        assertThrows(IllegalArgumentException.class, () -> TarjanBridges.findBridges(5, adj));
+    }
+
+    @Test
+    void testStarGraphAllEdgesAreBridges() {
+        // Star graph: center vertex 0 connected to 1, 2, 3, 4
+        List<List<Integer>> adj = buildGraph(5, new int[][] {{0, 1}, {0, 2}, {0, 3}, {0, 4}});
+        List<int[]> bridges = TarjanBridges.findBridges(5, adj);
+        assertEquals(4, bridges.size());
+    }
+
+    @Test
+    void testBridgeBetweenTwoCycles() {
+        // Two squares connected by one bridge:
+        // Square 1: 0-1-2-3-0
+        // Square 2: 4-5-6-7-4
+        // Bridge: 3-4
+        List<List<Integer>> adj = buildGraph(8, new int[][] {{0, 1}, {1, 2}, {2, 3}, {3, 0}, {4, 5}, {5, 6}, {6, 7}, {7, 4}, {3, 4}});
+        List<int[]> bridges = TarjanBridges.findBridges(8, adj);
+        assertEquals(1, bridges.size());
+        assertEquals(3, bridges.get(0)[0]);
+        assertEquals(4, bridges.get(0)[1]);
+    }
+}

From 8be75436ed863ac7e198dc889a71669d11c30354 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sun, 29 Mar 2026 23:37:03 +0200
Subject: [PATCH 1226/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.3.0 to 13.4.0 (#7352)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.3.0 to 13.4.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.3.0...checkstyle-13.4.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index dab7447430e5..c3629f165361 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.3.0</version>
+                    <version>13.4.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 5753f46f538e460b1246da699bfa700a091cddc3 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sun, 29 Mar 2026 21:40:59 +0000
Subject: [PATCH 1227/1338] chore(deps-dev): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.8.2 to 4.9.8.3 (#7353)

chore(deps-dev): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.8.2 to 4.9.8.3.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.8.2...spotbugs-maven-plugin-4.9.8.3)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.9.8.3
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index c3629f165361..74b6cd9bd485 100644
--- a/pom.xml
+++ b/pom.xml
@@ -119,7 +119,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.8.2</version>
+                <version>4.9.8.3</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From bdbbecedfc2b5263a4ddd749be3bfe34670e8b7d Mon Sep 17 00:00:00 2001
From: Senrian <47714364+Senrian@users.noreply.github.com>
Date: Mon, 30 Mar 2026 17:03:01 +0800
Subject: [PATCH 1228/1338] Improve JumpSearch documentation with detailed
 explanation and example (#7354)

Issue: #7349

Added:
- Step-by-step algorithm explanation
- Worked example with input/output
- Time and space complexity analysis
- Notes on when to use Jump Search vs Binary/Linear Search
- @see references to related search algorithms
---
 .../thealgorithms/searches/JumpSearch.java    | 40 +++++++++++++++----
 1 file changed, 32 insertions(+), 8 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/JumpSearch.java b/src/main/java/com/thealgorithms/searches/JumpSearch.java
index 8dcec3a819a4..cbc494c8c16a 100644
--- a/src/main/java/com/thealgorithms/searches/JumpSearch.java
+++ b/src/main/java/com/thealgorithms/searches/JumpSearch.java
@@ -12,26 +12,50 @@
  * Once the range is found, a linear search is performed within that block.
  *
  * <p>
- * The Jump Search algorithm is particularly effective for large sorted arrays where the cost of
- * performing a linear search on the entire array would be prohibitive.
+ * <b>How it works:</b>
+ * <ol>
+ *   <li>Calculate the optimal block size as √n (square root of array length)</li>
+ *   <li>Jump ahead by the block size until the current element is greater than the target</li>
+ *   <li>Perform a linear search backwards within the identified block</li>
+ * </ol>
  *
  * <p>
- * Worst-case performance: O(√N)<br>
- * Best-case performance: O(1)<br>
- * Average performance: O(√N)<br>
- * Worst-case space complexity: O(1)
+ * <b>Example:</b><br>
+ * Array: [1, 3, 5, 7, 9, 11, 13, 15, 17, 19], Target: 9<br>
+ * Step 1: Jump from index 0 → 3 → 6 (9 < 13, so we found the block)<br>
+ * Step 2: Linear search from index 3 to 6: found 9 at index 4<br>
+ * Result: Index = 4
+ *
+ * <p>
+ * <b>Time Complexity:</b><br>
+ * - Best-case: O(1) - element found at first position<br>
+ * - Average: O(√n) - optimal block size reduces jumps<br>
+ * - Worst-case: O(√n) - element at end of array or not present<br>
+ *
+ * <p>
+ * <b>Space Complexity:</b> O(1) - only uses a constant amount of extra space
+ *
+ * <p>
+ * <b>Note:</b> Jump Search requires a sorted array. For unsorted arrays, use Linear Search.
+ * Compared to Linear Search (O(n)), Jump Search is faster for large arrays.
+ * Compared to Binary Search (O(log n)), Jump Search is less efficient but may be
+ * preferable when jumping through a linked list or when backward scanning is costly.
  *
  * <p>
  * This class implements the {@link SearchAlgorithm} interface, providing a generic search method
  * for any comparable type.
+ *
+ * @see SearchAlgorithm
+ * @see BinarySearch
+ * @see LinearSearch
  */
 public class JumpSearch implements SearchAlgorithm {
 
     /**
      * Jump Search algorithm implementation.
      *
-     * @param array the sorted array containing elements
-     * @param key   the element to be searched
+     * @param array the sorted array containing elements (must be sorted in ascending order)
+     * @param key   the element to be searched for
      * @return the index of {@code key} if found, otherwise -1
      */
     @Override

From d2744b56173ca4936765d55457190098501e4617 Mon Sep 17 00:00:00 2001
From: Suraj Devatha <42767118+surajdm123@users.noreply.github.com>
Date: Mon, 30 Mar 2026 10:56:16 -0700
Subject: [PATCH 1229/1338] Fixes #7350: Binary Search Reliability Improvement
 (#7351)

---
 .../searches/BinarySearchTest.java            | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/src/test/java/com/thealgorithms/searches/BinarySearchTest.java b/src/test/java/com/thealgorithms/searches/BinarySearchTest.java
index bd4620a7fa7d..00bed165734e 100644
--- a/src/test/java/com/thealgorithms/searches/BinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/BinarySearchTest.java
@@ -105,4 +105,90 @@ void testBinarySearchLargeArray() {
         int expectedIndex = 9999; // Index of the last element
         assertEquals(expectedIndex, binarySearch.find(array, key), "The index of the last element should be 9999.");
     }
+
+    /**
+     * Test for binary search with null array.
+     */
+    @Test
+    void testBinarySearchNullArray() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = null;
+        int key = 5; // Key to search
+        int expectedIndex = -1; // Key not found
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The element should not be found in a null array.");
+    }
+
+    /**
+     * Test for binary search with duplicate elements.
+     */
+    @Test
+    void testBinarySearchWithDuplicates() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {1, 2, 2, 2, 3};
+        int key = 2; // Element present multiple times
+
+        int result = binarySearch.find(array, key);
+        assertEquals(2, array[result], "The returned index should contain the searched element.");
+    }
+
+    /**
+     * Test for binary search where all elements are the same.
+     */
+    @Test
+    void testBinarySearchAllElementsSame() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {5, 5, 5, 5, 5};
+        int key = 5; // All elements match
+
+        int result = binarySearch.find(array, key);
+        assertEquals(5, array[result], "The returned index should contain the searched element.");
+    }
+
+    /**
+     * Test for binary search with negative numbers.
+     */
+    @Test
+    void testBinarySearchNegativeNumbers() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {-10, -5, 0, 5, 10};
+        int key = -5; // Element present
+        int expectedIndex = 1; // Index of the element
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The index of the element should be 1.");
+    }
+
+    /**
+     * Test for binary search when key is smaller than all elements.
+     */
+    @Test
+    void testBinarySearchKeySmallerThanAll() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {10, 20, 30};
+        int key = 5; // Smaller than all elements
+        int expectedIndex = -1; // Key not found
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for binary search when key is larger than all elements.
+     */
+    @Test
+    void testBinarySearchKeyLargerThanAll() {
+        BinarySearch binarySearch = new BinarySearch();
+        Integer[] array = {10, 20, 30};
+        int key = 40; // Larger than all elements
+        int expectedIndex = -1; // Key not found
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The element should not be found in the array.");
+    }
+
+    /**
+     * Test for binary search with String array.
+     */
+    @Test
+    void testBinarySearchStrings() {
+        BinarySearch binarySearch = new BinarySearch();
+        String[] array = {"apple", "banana", "cherry", "date"};
+        String key = "cherry"; // Element present
+        int expectedIndex = 2; // Index of the element
+        assertEquals(expectedIndex, binarySearch.find(array, key), "The index of the element should be 2.");
+    }
 }

From ee343363c6158d91d7a180ac88e3749482bed291 Mon Sep 17 00:00:00 2001
From: kvadrik <41710943+kvadrik@users.noreply.github.com>
Date: Tue, 31 Mar 2026 19:34:30 +0300
Subject: [PATCH 1230/1338] Correlation function for discrete variable
 correlation (#7326)

* Correlation function for discrete variable correlation

* Add unit tests for Correlation class

Added unit tests for the Correlation class to validate correlation calculations under various scenarios, including linear dependence and constant values.

* Added missing bracket

* Refactor variable initialization in correlation method

* Remove unused imports and clean up CorrelationTest

* Fix formatting of variable declarations in correlation method

* Update Correlation.java

* Fix formatting in CorrelationTest.java

* Enhance comments in correlation function

Added detailed comments to the correlation function for better understanding.

* Add correlation tests for various scenarios

* Format comments for clarity in correlation method

* Fix formatting and comments in correlation method
---
 .../com/thealgorithms/maths/Correlation.java  | 51 +++++++++++++++++++
 .../thealgorithms/maths/CorrelationTest.java  | 51 +++++++++++++++++++
 2 files changed, 102 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/Correlation.java
 create mode 100644 src/test/java/com/thealgorithms/maths/CorrelationTest.java

diff --git a/src/main/java/com/thealgorithms/maths/Correlation.java b/src/main/java/com/thealgorithms/maths/Correlation.java
new file mode 100644
index 000000000000..a46445fb23b7
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/Correlation.java
@@ -0,0 +1,51 @@
+package com.thealgorithms.maths;
+
+/**
+ * Class for correlation of two discrete variables
+ */
+
+public final class Correlation {
+    private Correlation() {
+    }
+
+    public static final double DELTA = 1e-9;
+
+    /**
+     * Discrete correlation function.
+     * Correlation between two discrete variables is calculated
+     * according to the formula: Cor(x, y)=Cov(x, y)/sqrt(Var(x)*Var(y)).
+     * Correlation with a constant variable is taken to be zero.
+     *
+     * @param x The first discrete variable
+     * @param y The second discrete variable
+     * @param n The number of values for each variable
+     * @return The result of the correlation of variables x,y.
+     */
+    public static double correlation(double[] x, double[] y, int n) {
+        double exy = 0; // E(XY)
+        double ex = 0; // E(X)
+        double exx = 0; // E(X^2)
+        double ey = 0; // E(Y)
+        double eyy = 0; // E(Y^2)
+        for (int i = 0; i < n; i++) {
+            exy += x[i] * y[i];
+            ex += x[i];
+            exx += x[i] * x[i];
+            ey += y[i];
+            eyy += y[i] * y[i];
+        }
+        exy /= n;
+        ex /= n;
+        exx /= n;
+        ey /= n;
+        eyy /= n;
+        double cov = exy - ex * ey; // Cov(X, Y) = E(XY)-E(X)E(Y)
+        double varx = Math.sqrt(exx - ex * ex); // Var(X) = sqrt(E(X^2)-E(X)^2)
+        double vary = Math.sqrt(eyy - ey * ey); // Var(Y) = sqrt(E(Y^2)-E(Y)^2)
+        if (varx * vary < DELTA) { // Var(X) = 0 means X = const, the same about Y
+            return 0;
+        } else {
+            return cov / Math.sqrt(varx * vary);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/CorrelationTest.java b/src/test/java/com/thealgorithms/maths/CorrelationTest.java
new file mode 100644
index 000000000000..96867d56ad5e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/CorrelationTest.java
@@ -0,0 +1,51 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Test class for Correlation class
+ */
+public class CorrelationTest {
+
+    public static final double DELTA = 1e-9;
+
+    // Regular correlation test
+    public void testCorrelationFirst() {
+        double[] x = {1, 2, 3, 4};
+        double[] y = {7, 1, 4, 9};
+        int n = 4;
+        assertEquals(0.3319700011, Correlation.correlation(x, y, n), DELTA);
+    }
+
+    // Regular correlation test (zero correlation)
+    public void testCorrelationSecond() {
+        double[] x = {1, 2, 3, 4};
+        double[] y = {5, 0, 9, 2};
+        int n = 4;
+        assertEquals(0, Correlation.correlation(x, y, n), DELTA);
+    }
+
+    // Correlation with a constant variable is taken to be zero
+    public void testCorrelationConstant() {
+        double[] x = {1, 2, 3};
+        double[] y = {4, 4, 4};
+        int n = 3;
+        assertEquals(0, Correlation.correlation(x, y, n), DELTA);
+    }
+
+    // Linear dependence gives correlation 1
+    public void testCorrelationLinearDependence() {
+        double[] x = {1, 2, 3, 4};
+        double[] y = {6, 8, 10, 12};
+        int n = 4;
+        assertEquals(1, Correlation.correlation(x, y, n), DELTA);
+    }
+
+    // Inverse linear dependence gives correlation -1
+    public void testCorrelationInverseLinearDependence() {
+        double[] x = {1, 2, 3, 4, 5};
+        double[] y = {18, 15, 12, 9, 6};
+        int n = 5;
+        assertEquals(-1, Correlation.correlation(x, y, n), DELTA);
+    }
+}

From 635d54a9de573a51786b18b151579206b58ae947 Mon Sep 17 00:00:00 2001
From: Senrian <47714364+Senrian@users.noreply.github.com>
Date: Wed, 1 Apr 2026 19:03:57 +0800
Subject: [PATCH 1231/1338] fix(BinarySearch): add null key check to prevent
 NPE (fix #7356) (#7357)

fix(BinarySearch): add null key check to prevent NPE

Issue #7356: Add null check for the search value to prevent potential NullPointerException.
---
 .../java/com/thealgorithms/searches/BinarySearch.java    | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/BinarySearch.java b/src/main/java/com/thealgorithms/searches/BinarySearch.java
index 7a5361b280ea..ca873fc6eafa 100644
--- a/src/main/java/com/thealgorithms/searches/BinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/BinarySearch.java
@@ -58,11 +58,18 @@ class BinarySearch implements SearchAlgorithm {
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
-        // Handle edge case: empty array
+        // Handle edge case: null or empty array
         if (array == null || array.length == 0) {
             return -1;
         }
 
+        // Handle edge case: null key
+        // Searching for null in an array of Comparables is undefined behavior
+        // Return -1 to indicate not found rather than throwing NPE
+        if (key == null) {
+            return -1;
+        }
+
         // Delegate to the core search implementation
         return search(array, key, 0, array.length - 1);
     }

From 9729e56fc7b54197460ee449d94d33284c68d7aa Mon Sep 17 00:00:00 2001
From: Vansh Sharma <Vansh.Sharma7171717@gmail.com>
Date: Wed, 1 Apr 2026 17:25:29 +0530
Subject: [PATCH 1232/1338] Use BigInteger to prevent overflow in factorial
 calculation (#7358)

* Use BigInteger to prevent overflow in factorial calculation

* chore: remove unnecessary comment

* update

* Fix: improve factorial implementation and formatting

* test: final fix for FactorialTest logic and formatting

* chore: final formatting and test fix for BigInteger

* chore: final formatting and test fix for BigInteger
---
 .../com/thealgorithms/maths/Factorial.java     | 18 +++++++-----------
 .../com/thealgorithms/maths/FactorialTest.java |  9 +++++----
 2 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Factorial.java b/src/main/java/com/thealgorithms/maths/Factorial.java
index 511cc1f84f05..8ad219a3066c 100644
--- a/src/main/java/com/thealgorithms/maths/Factorial.java
+++ b/src/main/java/com/thealgorithms/maths/Factorial.java
@@ -1,23 +1,19 @@
 package com.thealgorithms.maths;
 
+import java.math.BigInteger;
+
 public final class Factorial {
     private Factorial() {
     }
 
-    /**
-     * Calculate factorial N using iteration
-     *
-     * @param n the number
-     * @return the factorial of {@code n}
-     */
-    public static long factorial(int n) {
+    public static BigInteger factorial(int n) {
         if (n < 0) {
             throw new IllegalArgumentException("Input number cannot be negative");
         }
-        long factorial = 1;
-        for (int i = 1; i <= n; ++i) {
-            factorial *= i;
+        BigInteger result = BigInteger.ONE;
+        for (int i = 1; i <= n; i++) {
+            result = result.multiply(BigInteger.valueOf(i));
         }
-        return factorial;
+        return result;
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/FactorialTest.java b/src/test/java/com/thealgorithms/maths/FactorialTest.java
index 3ff7097b8113..a393136696e1 100644
--- a/src/test/java/com/thealgorithms/maths/FactorialTest.java
+++ b/src/test/java/com/thealgorithms/maths/FactorialTest.java
@@ -3,6 +3,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.math.BigInteger;
 import org.junit.jupiter.api.Test;
 
 public class FactorialTest {
@@ -16,9 +17,9 @@ public void testWhenInvalidInoutProvidedShouldThrowException() {
 
     @Test
     public void testCorrectFactorialCalculation() {
-        assertEquals(1, Factorial.factorial(0));
-        assertEquals(1, Factorial.factorial(1));
-        assertEquals(120, Factorial.factorial(5));
-        assertEquals(3628800, Factorial.factorial(10));
+        assertEquals(BigInteger.ONE, Factorial.factorial(0));
+        assertEquals(BigInteger.ONE, Factorial.factorial(1));
+        assertEquals(BigInteger.valueOf(120), Factorial.factorial(5));
+        assertEquals(BigInteger.valueOf(3628800), Factorial.factorial(10));
     }
 }

From f38d5cdb3c33589c0e171b17f1daad6634fba963 Mon Sep 17 00:00:00 2001
From: Alex Tumanov <oleksii.tumanov@gmail.com>
Date: Fri, 3 Apr 2026 06:50:11 -0500
Subject: [PATCH 1233/1338] feat: add OptimalBinarySearchTree algorithm (#7310)

---
 .../OptimalBinarySearchTree.java              | 130 ++++++++++++++++++
 .../OptimalBinarySearchTreeTest.java          |  73 ++++++++++
 2 files changed, 203 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/OptimalBinarySearchTree.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/OptimalBinarySearchTreeTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/OptimalBinarySearchTree.java b/src/main/java/com/thealgorithms/dynamicprogramming/OptimalBinarySearchTree.java
new file mode 100644
index 000000000000..428176ea6c40
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/OptimalBinarySearchTree.java
@@ -0,0 +1,130 @@
+package com.thealgorithms.dynamicprogramming;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+/**
+ * Computes the minimum search cost of an optimal binary search tree.
+ *
+ * <p>The algorithm sorts the keys, preserves the corresponding search frequencies, and uses
+ * dynamic programming with Knuth's optimization to compute the minimum weighted search cost.
+ *
+ * <p>Example: if keys = [10, 12] and frequencies = [34, 50], the best tree puts 12 at the root
+ * and 10 as its left child. The total cost is 50 * 1 + 34 * 2 = 118.
+ *
+ * <p>Reference:
+ * https://en.wikipedia.org/wiki/Optimal_binary_search_tree
+ */
+public final class OptimalBinarySearchTree {
+    private OptimalBinarySearchTree() {
+    }
+
+    /**
+     * Computes the minimum weighted search cost for the given keys and search frequencies.
+     *
+     * @param keys the BST keys
+     * @param frequencies the search frequencies associated with the keys
+     * @return the minimum search cost
+     * @throws IllegalArgumentException if the input is invalid
+     */
+    public static long findOptimalCost(int[] keys, int[] frequencies) {
+        validateInput(keys, frequencies);
+        if (keys.length == 0) {
+            return 0L;
+        }
+
+        int[][] sortedNodes = sortNodes(keys, frequencies);
+        int nodeCount = sortedNodes.length;
+        long[] prefixSums = buildPrefixSums(sortedNodes);
+        long[][] optimalCost = new long[nodeCount][nodeCount];
+        int[][] root = new int[nodeCount][nodeCount];
+
+        // Small example:
+        // keys        = [10, 12]
+        // frequencies = [34, 50]
+        // Choosing 12 as the root gives cost 50 * 1 + 34 * 2 = 118,
+        // which is better than choosing 10 as the root.
+
+        // Base case: a subtree containing one key has cost equal to its frequency,
+        // because that key becomes the root of the subtree and is searched at depth 1.
+        for (int index = 0; index < nodeCount; index++) {
+            optimalCost[index][index] = sortedNodes[index][1];
+            root[index][index] = index;
+        }
+
+        // Build solutions for longer and longer key ranges.
+        // optimalCost[start][end] stores the minimum search cost for keys in that range.
+        for (int length = 2; length <= nodeCount; length++) {
+            for (int start = 0; start <= nodeCount - length; start++) {
+                int end = start + length - 1;
+
+                // Every key in this range moves one level deeper when we choose a root,
+                // so the sum of frequencies is added once to the subtree cost.
+                long frequencySum = prefixSums[end + 1] - prefixSums[start];
+                optimalCost[start][end] = Long.MAX_VALUE;
+
+                // Knuth's optimization:
+                // the best root for [start, end] lies between the best roots of
+                // [start, end - 1] and [start + 1, end], so we search only this interval.
+                int leftBoundary = root[start][end - 1];
+                int rightBoundary = root[start + 1][end];
+                for (int currentRoot = leftBoundary; currentRoot <= rightBoundary; currentRoot++) {
+                    long leftCost = currentRoot > start ? optimalCost[start][currentRoot - 1] : 0L;
+                    long rightCost = currentRoot < end ? optimalCost[currentRoot + 1][end] : 0L;
+                    long currentCost = frequencySum + leftCost + rightCost;
+
+                    if (currentCost < optimalCost[start][end]) {
+                        optimalCost[start][end] = currentCost;
+                        root[start][end] = currentRoot;
+                    }
+                }
+            }
+        }
+
+        return optimalCost[0][nodeCount - 1];
+    }
+
+    private static void validateInput(int[] keys, int[] frequencies) {
+        if (keys == null || frequencies == null) {
+            throw new IllegalArgumentException("Keys and frequencies cannot be null");
+        }
+        if (keys.length != frequencies.length) {
+            throw new IllegalArgumentException("Keys and frequencies must have the same length");
+        }
+
+        for (int frequency : frequencies) {
+            if (frequency < 0) {
+                throw new IllegalArgumentException("Frequencies cannot be negative");
+            }
+        }
+    }
+
+    private static int[][] sortNodes(int[] keys, int[] frequencies) {
+        int[][] sortedNodes = new int[keys.length][2];
+        for (int index = 0; index < keys.length; index++) {
+            sortedNodes[index][0] = keys[index];
+            sortedNodes[index][1] = frequencies[index];
+        }
+
+        // Sort by key so the nodes can be treated as an in-order BST sequence.
+        Arrays.sort(sortedNodes, Comparator.comparingInt(node -> node[0]));
+
+        for (int index = 1; index < sortedNodes.length; index++) {
+            if (sortedNodes[index - 1][0] == sortedNodes[index][0]) {
+                throw new IllegalArgumentException("Keys must be distinct");
+            }
+        }
+
+        return sortedNodes;
+    }
+
+    private static long[] buildPrefixSums(int[][] sortedNodes) {
+        long[] prefixSums = new long[sortedNodes.length + 1];
+        for (int index = 0; index < sortedNodes.length; index++) {
+            // prefixSums[i] holds the total frequency of the first i sorted keys.
+            // This lets us get the frequency sum of any range in O(1) time.
+            prefixSums[index + 1] = prefixSums[index] + sortedNodes[index][1];
+        }
+        return prefixSums;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/OptimalBinarySearchTreeTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/OptimalBinarySearchTreeTest.java
new file mode 100644
index 000000000000..17ff3ec728dc
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/OptimalBinarySearchTreeTest.java
@@ -0,0 +1,73 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.Arrays;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class OptimalBinarySearchTreeTest {
+
+    @ParameterizedTest
+    @MethodSource("validTestCases")
+    void testFindOptimalCost(int[] keys, int[] frequencies, long expectedCost) {
+        assertEquals(expectedCost, OptimalBinarySearchTree.findOptimalCost(keys, frequencies));
+    }
+
+    private static Stream<Arguments> validTestCases() {
+        return Stream.of(Arguments.of(new int[] {}, new int[] {}, 0L), Arguments.of(new int[] {15}, new int[] {9}, 9L), Arguments.of(new int[] {10, 12}, new int[] {34, 50}, 118L), Arguments.of(new int[] {20, 10, 30}, new int[] {50, 34, 8}, 134L),
+            Arguments.of(new int[] {12, 10, 20, 42, 25, 37}, new int[] {8, 34, 50, 3, 40, 30}, 324L), Arguments.of(new int[] {1, 2, 3}, new int[] {0, 0, 0}, 0L));
+    }
+
+    @ParameterizedTest
+    @MethodSource("crossCheckTestCases")
+    void testFindOptimalCostAgainstBruteForce(int[] keys, int[] frequencies) {
+        assertEquals(bruteForceOptimalCost(keys, frequencies), OptimalBinarySearchTree.findOptimalCost(keys, frequencies));
+    }
+
+    private static Stream<Arguments> crossCheckTestCases() {
+        return Stream.of(Arguments.of(new int[] {3, 1, 2}, new int[] {4, 2, 6}), Arguments.of(new int[] {5, 2, 8, 6}, new int[] {3, 7, 1, 4}), Arguments.of(new int[] {9, 4, 11, 2}, new int[] {1, 8, 2, 5}));
+    }
+
+    @ParameterizedTest
+    @MethodSource("invalidTestCases")
+    void testFindOptimalCostInvalidInput(int[] keys, int[] frequencies) {
+        assertThrows(IllegalArgumentException.class, () -> OptimalBinarySearchTree.findOptimalCost(keys, frequencies));
+    }
+
+    private static Stream<Arguments> invalidTestCases() {
+        return Stream.of(Arguments.of(null, new int[] {}), Arguments.of(new int[] {}, null), Arguments.of(new int[] {1, 2}, new int[] {3}), Arguments.of(new int[] {1, 1}, new int[] {2, 3}), Arguments.of(new int[] {1, 2}, new int[] {3, -1}));
+    }
+
+    private static long bruteForceOptimalCost(int[] keys, int[] frequencies) {
+        int[][] sortedNodes = new int[keys.length][2];
+        for (int index = 0; index < keys.length; index++) {
+            sortedNodes[index][0] = keys[index];
+            sortedNodes[index][1] = frequencies[index];
+        }
+        Arrays.sort(sortedNodes, java.util.Comparator.comparingInt(node -> node[0]));
+
+        int[] sortedFrequencies = new int[sortedNodes.length];
+        for (int index = 0; index < sortedNodes.length; index++) {
+            sortedFrequencies[index] = sortedNodes[index][1];
+        }
+
+        return bruteForceOptimalCost(sortedFrequencies, 0, sortedFrequencies.length - 1, 1);
+    }
+
+    private static long bruteForceOptimalCost(int[] frequencies, int start, int end, int depth) {
+        if (start > end) {
+            return 0L;
+        }
+
+        long minimumCost = Long.MAX_VALUE;
+        for (int root = start; root <= end; root++) {
+            long currentCost = (long) depth * frequencies[root] + bruteForceOptimalCost(frequencies, start, root - 1, depth + 1) + bruteForceOptimalCost(frequencies, root + 1, end, depth + 1);
+            minimumCost = Math.min(minimumCost, currentCost);
+        }
+        return minimumCost;
+    }
+}

From b7e9c85c43a23515cadc34e9b71484b198c7af2b Mon Sep 17 00:00:00 2001
From: AbhiramSakha <143825001+AbhiramSakha@users.noreply.github.com>
Date: Sun, 5 Apr 2026 03:13:50 +0530
Subject: [PATCH 1234/1338] Enhance LinearSearch with null check for value
 (#7355)

Added null check for the search value in the find method.
---
 .../java/com/thealgorithms/searches/LinearSearch.java    | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/LinearSearch.java b/src/main/java/com/thealgorithms/searches/LinearSearch.java
index 00fb9c2d0fcf..77ecece3aaef 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearch.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearch.java
@@ -14,6 +14,7 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
+
 /**
  * Linear Search is a simple searching algorithm that checks
  * each element of the array sequentially until the target
@@ -33,7 +34,6 @@
  * @see BinarySearch
  * @see SearchAlgorithm
  */
-
 public class LinearSearch implements SearchAlgorithm {
 
     /**
@@ -45,14 +45,17 @@ public class LinearSearch implements SearchAlgorithm {
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T value) {
-        if (array == null || array.length == 0) {
+
+        if (array == null || array.length == 0 || value == null) {
             return -1;
         }
+
         for (int i = 0; i < array.length; i++) {
-            if (array[i].compareTo(value) == 0) {
+            if (array[i] != null && array[i].compareTo(value) == 0) {
                 return i;
             }
         }
+
         return -1;
     }
 }

From abd1c4732f4369a500cd164489e68f3e5fd4aba8 Mon Sep 17 00:00:00 2001
From: kvadrik <41710943+kvadrik@users.noreply.github.com>
Date: Sun, 5 Apr 2026 00:58:45 +0300
Subject: [PATCH 1235/1338] Create Relativity.java (#7323)

* Create Relativity.java

Created the file that implements relativity formulae.

* Create RelativityTest.java

Test file created for Relativity.java.

* Update RelativityTest.java

Function name ambiguity resolved

* Update RelativityTest.java

DELTA increased

* Update Relativity.java

Extra white space removed

* Update Relativity.java

Extra spaces added

* Update RelativityTest.java

Spaces added and removed

* Update Relativity.java

White spaces added and removed

* Update RelativityTest.java

Added and removed spaces

* Update Relativity.java

* Update Relativity.java

Space removed

* Update Relativity.java

Replaced tabs by spaces

* Update RelativityTest.java

Tabs replaced by spaces
---
 .../com/thealgorithms/physics/Relativity.java | 81 +++++++++++++++++++
 .../thealgorithms/physics/RelativityTest.java | 73 +++++++++++++++++
 2 files changed, 154 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/physics/Relativity.java
 create mode 100644 src/test/java/com/thealgorithms/physics/RelativityTest.java

diff --git a/src/main/java/com/thealgorithms/physics/Relativity.java b/src/main/java/com/thealgorithms/physics/Relativity.java
new file mode 100644
index 000000000000..ed823c2cc879
--- /dev/null
+++ b/src/main/java/com/thealgorithms/physics/Relativity.java
@@ -0,0 +1,81 @@
+package com.thealgorithms.physics;
+
+/**
+ * Implements relativity theory formulae.
+ * Provides simple static methods to calculate length contraction and time dilation
+ * in the laboratory frame with respect to the object's own frame, and velocity
+ * with respect to the moving frame.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/List_of_relativistic_equations">Wikipedia</a>
+ */
+public final class Relativity {
+
+    /* Speed of light in m s^-1 */
+    public static final double SPEED_OF_LIGHT = 299792458.0;
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private Relativity() {
+    }
+
+    /**
+     * Calculates the gamma parameter that is of paramount importance in relativity
+     * theory. It is a dimensionless parameter that is equal to 1 for zero velocity
+     * but tends to infinity when velocity approaches the speed of light.
+     *
+     * @param v The velocity (m/s).
+     * @return The value of gamma parameter.
+     */
+    public static double gamma(double v) {
+        if (Math.abs(v) >= SPEED_OF_LIGHT) {
+            throw new IllegalArgumentException("Speed must be lower than the speed of light");
+        }
+        return 1.0 / Math.sqrt(1 - v * v / (SPEED_OF_LIGHT * SPEED_OF_LIGHT));
+    }
+
+    /**
+     * Calculates the length of an object in the moving frame.
+     *
+     * @param length The length of an object in its own frame (m).
+     * @param v The velocity of the object (m/s).
+     * @return The length of an object in the laboratory frame (m).
+     */
+    public static double lengthContraction(double length, double v) {
+        if (length < 0) {
+            throw new IllegalArgumentException("Length must be non-negative");
+        }
+        return length / gamma(v);
+    }
+
+    /**
+     * Calculates the time that has passed in the moving frame.
+     *
+     * @param length The time that has passed in the object's own frame (s).
+     * @param v The velocity of the object (m/s).
+     * @return The time that has passed in the laboratory frame (s).
+     */
+    public static double timeDilation(double time, double v) {
+        if (time < 0) {
+            throw new IllegalArgumentException("Time must be non-negative");
+        }
+        return time * gamma(v);
+    }
+
+    /**
+     * Calculates the velocity with respect to the moving frame.
+     *
+     * @param v1 The velocity of the object with respect to laboratory frame (m/s).
+     * @param v The velocity of the moving frame (m/s).
+     * @return The velocity with respect to the moving frame (m/s).
+     */
+    public static double velocityAddition(double v1, double v) {
+        if (Math.abs(v1) > SPEED_OF_LIGHT) {
+            throw new IllegalArgumentException("Speed must not exceed the speed of light");
+        }
+        if (Math.abs(v) >= SPEED_OF_LIGHT) {
+            throw new IllegalArgumentException("Frame speed must be lower than the speed of light");
+        }
+        return (v1 - v) / (1 - v1 * v / (SPEED_OF_LIGHT * SPEED_OF_LIGHT));
+    }
+}
diff --git a/src/test/java/com/thealgorithms/physics/RelativityTest.java b/src/test/java/com/thealgorithms/physics/RelativityTest.java
new file mode 100644
index 000000000000..44c17bdbd40f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/physics/RelativityTest.java
@@ -0,0 +1,73 @@
+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the Relativity utility class.
+ */
+final class RelativityTest {
+
+    // A small tolerance (delta) for comparing floating-point numbers
+    private static final double DELTA = 1e-6;
+    private static final double C = Relativity.SPEED_OF_LIGHT;
+
+    @Test
+    @DisplayName("Test the gamma parameter")
+    void testGamma() {
+        double myGamma = Relativity.gamma(0.6 * C);
+        assertEquals(1.25, myGamma, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test the length contraction")
+    void testLengthContraction() {
+        double myLength = Relativity.lengthContraction(5.0, 0.8 * C);
+        assertEquals(3.0, myLength, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test the time dilation")
+    void testTimeDilation() {
+        double myTime = Relativity.timeDilation(4.0, 0.6 * C);
+        assertEquals(5.0, myTime, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test the velocity addition in the same direction")
+    void testVelocityAdditionSameDirection() {
+        double myVelocity = Relativity.velocityAddition(0.8 * C, 0.75 * C);
+        assertEquals(0.125 * C, myVelocity, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test the velocity addition in different directions")
+    void testVelocityAdditionDifferentDirections() {
+        double myVelocity = Relativity.velocityAddition(0.8 * C, -0.75 * C);
+        assertEquals(0.96875 * C, myVelocity, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test the velocity addition with the speed of light")
+    void testVelocityAdditionWithSpeedOfLight() {
+        double myVelocity = Relativity.velocityAddition(C, 0.7 * C);
+        assertEquals(C, myVelocity, DELTA);
+    }
+
+    @Test
+    @DisplayName("Test invalid inputs throw exception")
+    void testInvalidOrbitalVelocityInputs() {
+        assertThrows(IllegalArgumentException.class, () -> Relativity.gamma(1.2 * C));
+        assertThrows(IllegalArgumentException.class, () -> Relativity.gamma(-C));
+        assertThrows(IllegalArgumentException.class, () -> Relativity.lengthContraction(-1.0, 0.6 * C));
+        assertThrows(IllegalArgumentException.class, () -> Relativity.lengthContraction(1.0, 1.5 * C));
+        assertThrows(IllegalArgumentException.class, () -> Relativity.timeDilation(-5.0, -0.8 * C));
+        assertThrows(IllegalArgumentException.class, () -> Relativity.timeDilation(5.0, C));
+        assertThrows(IllegalArgumentException.class, () -> Relativity.velocityAddition(0.3 * C, -C));
+        assertThrows(IllegalArgumentException.class, () -> Relativity.velocityAddition(1.4 * C, 0.2 * C));
+        assertThrows(IllegalArgumentException.class, () -> Relativity.velocityAddition(-0.4 * C, 1.2 * C));
+    }
+}

From 13aaad21135611953d1e310e5535e4f181a1a4dc Mon Sep 17 00:00:00 2001
From: Shyam Chavda <163722988+ShyamChavda005@users.noreply.github.com>
Date: Sun, 5 Apr 2026 22:36:07 +0530
Subject: [PATCH 1236/1338] feat(strings): add MoveHashToEnd algorithm (#7313)

* feat(strings): add MoveHashToEnd algorithm with tests

- Add MoveHashToEnd utility class that moves all '#' characters
  to the end of a string while preserving the order of other characters
- Algorithm runs in O(n) time and O(n) space using a two-pass approach:
  first collects non-'#' chars, then fills remaining positions with '#'
- Add null and empty string guards
- Add MoveHashToEndTest with 9 unit tests covering normal, edge,
  and boundary cases (null, empty, all-hash, no-hash, single char)

* docs(strings): add reference URL to MoveHashToEnd Javadoc

* docs: add MoveHashToEnd to DIRECTORY index

* style(strings): add missing newline at EOF in MoveHashToEnd

* test(strings): fix MoveHashToEnd expected output for sample input
---
 DIRECTORY.md                                  |  1 +
 .../thealgorithms/strings/MoveHashToEnd.java  | 56 +++++++++++++++++++
 .../strings/MoveHashToEndTest.java            | 54 ++++++++++++++++++
 3 files changed, 111 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/MoveHashToEnd.java
 create mode 100644 src/test/java/com/thealgorithms/strings/MoveHashToEndTest.java

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 585c634c3429..37d9b3c295e2 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -816,6 +816,7 @@
           - 📄 [Lower](src/main/java/com/thealgorithms/strings/Lower.java)
           - 📄 [Manacher](src/main/java/com/thealgorithms/strings/Manacher.java)
           - 📄 [MyAtoi](src/main/java/com/thealgorithms/strings/MyAtoi.java)
+          - 📄 [MoveHashToEnd](src/main/java/com/thealgorithms/strings/MoveHashToEnd.java)
           - 📄 [Palindrome](src/main/java/com/thealgorithms/strings/Palindrome.java)
           - 📄 [Pangram](src/main/java/com/thealgorithms/strings/Pangram.java)
           - 📄 [PermuteString](src/main/java/com/thealgorithms/strings/PermuteString.java)
diff --git a/src/main/java/com/thealgorithms/strings/MoveHashToEnd.java b/src/main/java/com/thealgorithms/strings/MoveHashToEnd.java
new file mode 100644
index 000000000000..bd686a0c5ba0
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/MoveHashToEnd.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.strings;
+
+/**
+ * Moves all '#' characters to the end of the given string while preserving
+ * the order of the other characters.
+ *
+ * Example:
+ * Input  : "h#e#l#llo"
+ * Output : "helllo###"
+ *
+ * The algorithm works by iterating through the string and collecting
+ * all non-# characters first, then filling the remaining positions
+ * with '#'.
+ *
+ * Time Complexity: O(n)
+ * Space Complexity: O(n)
+ *
+ * @see <a href="https://www.geeksforgeeks.org/move-special-char-end-string-maintain-order-alphabets/">Move all special characters to end - GeeksForGeeks</a>
+ */
+public final class MoveHashToEnd {
+
+    /**
+     * Private constructor to prevent instantiation of utility class.
+     */
+    private MoveHashToEnd() {
+    }
+
+    /**
+     * Moves all '#' characters in the input string to the end.
+     *
+     * @param str the input string containing characters and '#'
+     * @return a new string with all '#' characters moved to the end
+     */
+    public static String moveHashToEnd(String str) {
+        if (str == null || str.isEmpty()) {
+            return str;
+        }
+
+        char[] arr = str.toCharArray();
+        int insertPos = 0;
+
+        // Place all non-# characters at the beginning
+        for (char ch : arr) {
+            if (ch != '#') {
+                arr[insertPos++] = ch;
+            }
+        }
+
+        // Fill remaining positions with '#'
+        while (insertPos < arr.length) {
+            arr[insertPos++] = '#';
+        }
+
+        return new String(arr);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/MoveHashToEndTest.java b/src/test/java/com/thealgorithms/strings/MoveHashToEndTest.java
new file mode 100644
index 000000000000..016f72ff9d7f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/MoveHashToEndTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.strings;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+public class MoveHashToEndTest {
+
+    @Test
+    void testBasicCase() {
+        assertEquals("helllo###", MoveHashToEnd.moveHashToEnd("h#e#l#llo"));
+    }
+
+    @Test
+    void testNoHash() {
+        assertEquals("hello", MoveHashToEnd.moveHashToEnd("hello"));
+    }
+
+    @Test
+    void testAllHashes() {
+        assertEquals("###", MoveHashToEnd.moveHashToEnd("###"));
+    }
+
+    @Test
+    void testHashAtEnd() {
+        assertEquals("hello#", MoveHashToEnd.moveHashToEnd("hello#"));
+    }
+
+    @Test
+    void testHashAtStart() {
+        assertEquals("hello#", MoveHashToEnd.moveHashToEnd("#hello"));
+    }
+
+    @Test
+    void testEmptyString() {
+        assertEquals("", MoveHashToEnd.moveHashToEnd(""));
+    }
+
+    @Test
+    void testNullInput() {
+        assertNull(MoveHashToEnd.moveHashToEnd(null));
+    }
+
+    @Test
+    void testSingleHash() {
+        assertEquals("#", MoveHashToEnd.moveHashToEnd("#"));
+    }
+
+    @Test
+    void testSingleNonHashChar() {
+        assertEquals("a", MoveHashToEnd.moveHashToEnd("a"));
+    }
+}

From 741b2d10944fe85f0cea81b6e6f2d01eb8d29182 Mon Sep 17 00:00:00 2001
From: Yassa Talaat <145781920+YassaTalaat80@users.noreply.github.com>
Date: Mon, 6 Apr 2026 18:42:14 +0200
Subject: [PATCH 1237/1338] Feat/segment tree 2d (#7363)

* feat: add 2D segment tree implementation

* test: add comprehensive unit tests for 2D segment tree

* style: format code using clang-format
---
 .../datastructures/trees/SegmentTree2D.java   | 201 ++++++++++++++++++
 .../trees/SegmentTree2DTest.java              |  71 +++++++
 2 files changed, 272 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/trees/SegmentTree2D.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/SegmentTree2DTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree2D.java b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree2D.java
new file mode 100644
index 000000000000..40b9e8a73533
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree2D.java
@@ -0,0 +1,201 @@
+package com.thealgorithms.datastructures.trees;
+
+/**
+ * 2D Segment Tree (Tree of Trees) implementation.
+ * This data structure supports point updates and submatrix sum queries
+ * in a 2D grid. It achieves this by nesting 1D Segment Trees within a 1D Segment Tree.
+ *
+ * Time Complexity:
+ * - Build/Initialization: O(N * M)
+ * - Point Update: O(log N * log M)
+ * - Submatrix Query: O(log N * log M)
+ *
+ * @see <a href="https://cp-algorithms.com/data_structures/segment_tree.html#2d-segment-tree">2D Segment Tree</a>
+ */
+public class SegmentTree2D {
+
+    /**
+     * Represents a 1D Segment Tree.
+     * This is equivalent to your 'Sagara' struct. It manages the columns (X-axis).
+     */
+    public static class SegmentTree1D {
+        private int n;
+        private final int[] tree;
+
+        /**
+         * Initializes the 1D Segment Tree with the nearest power of 2.
+         *
+         * @param size The expected number of elements (columns).
+         */
+        public SegmentTree1D(int size) {
+            n = 1;
+            while (n < size) {
+                n *= 2;
+            }
+            tree = new int[n * 2];
+        }
+
+        /**
+         * Recursively updates a point in the 1D tree.
+         */
+        private void update(int index, int val, int node, int lx, int rx) {
+            if (rx - lx == 1) {
+                tree[node] = val;
+                return;
+            }
+
+            int mid = lx + (rx - lx) / 2;
+            int leftChild = node * 2 + 1;
+            int rightChild = node * 2 + 2;
+
+            if (index < mid) {
+                update(index, val, leftChild, lx, mid);
+            } else {
+                update(index, val, rightChild, mid, rx);
+            }
+
+            tree[node] = tree[leftChild] + tree[rightChild];
+        }
+
+        /**
+         * Public wrapper to update a specific index.
+         *
+         * @param index The column index to update.
+         * @param val   The new value.
+         */
+        public void update(int index, int val) {
+            update(index, val, 0, 0, n);
+        }
+
+        /**
+         * Retrieves the exact value at a specific leaf node.
+         *
+         * @param index The column index.
+         * @return The value at the given index.
+         */
+        public int get(int index) {
+            return query(index, index + 1, 0, 0, n);
+        }
+
+        /**
+         * Recursively queries the sum in a 1D range.
+         */
+        private int query(int l, int r, int node, int lx, int rx) {
+            if (lx >= r || rx <= l) {
+                return 0; // Out of bounds
+            }
+            if (lx >= l && rx <= r) {
+                return tree[node]; // Fully inside
+            }
+
+            int mid = lx + (rx - lx) / 2;
+            int leftSum = query(l, r, node * 2 + 1, lx, mid);
+            int rightSum = query(l, r, node * 2 + 2, mid, rx);
+
+            return leftSum + rightSum;
+        }
+
+        /**
+         * Public wrapper to query the sum in the range [l, r).
+         *
+         * @param l Left boundary (inclusive).
+         * @param r Right boundary (exclusive).
+         * @return The sum of the range.
+         */
+        public int query(int l, int r) {
+            return query(l, r, 0, 0, n);
+        }
+    }
+
+    // --- Start of 2D Segment Tree (equivalent to 'Sagara2D') ---
+
+    private int n;
+    private final SegmentTree1D[] tree;
+
+    /**
+     * Initializes the 2D Segment Tree.
+     *
+     * @param rows The number of rows in the matrix.
+     * @param cols The number of columns in the matrix.
+     */
+    public SegmentTree2D(int rows, int cols) {
+        n = 1;
+        while (n < rows) {
+            n *= 2;
+        }
+        tree = new SegmentTree1D[n * 2];
+        for (int i = 0; i < n * 2; i++) {
+            // Every node in the outer tree is a full 1D tree!
+            tree[i] = new SegmentTree1D(cols);
+        }
+    }
+
+    /**
+     * Recursively updates a point in the 2D grid.
+     */
+    private void update(int row, int col, int val, int node, int lx, int rx) {
+        if (rx - lx == 1) {
+            tree[node].update(col, val);
+            return;
+        }
+
+        int mid = lx + (rx - lx) / 2;
+        int leftChild = node * 2 + 1;
+        int rightChild = node * 2 + 2;
+
+        if (row < mid) {
+            update(row, col, val, leftChild, lx, mid);
+        } else {
+            update(row, col, val, rightChild, mid, rx);
+        }
+
+        // The value of the current node's column is the sum of its children's column values
+        int leftVal = tree[leftChild].get(col);
+        int rightVal = tree[rightChild].get(col);
+        tree[node].update(col, leftVal + rightVal);
+    }
+
+    /**
+     * Public wrapper to update a specific point (row, col).
+     *
+     * @param row The row index.
+     * @param col The column index.
+     * @param val The new value.
+     */
+    public void update(int row, int col, int val) {
+        update(row, col, val, 0, 0, n);
+    }
+
+    /**
+     * Recursively queries the sum in a submatrix.
+     */
+    private int query(int top, int bottom, int left, int right, int node, int lx, int rx) {
+        if (lx >= bottom || rx <= top) {
+            return 0; // Out of bounds
+        }
+        if (lx >= top && rx <= bottom) {
+            // Fully inside the row range, so delegate the column query to the 1D tree
+            return tree[node].query(left, right);
+        }
+
+        int mid = lx + (rx - lx) / 2;
+        int leftSum = query(top, bottom, left, right, node * 2 + 1, lx, mid);
+        int rightSum = query(top, bottom, left, right, node * 2 + 2, mid, rx);
+
+        return leftSum + rightSum;
+    }
+
+    /**
+     * Public wrapper to query the sum of a submatrix.
+     * Note: boundaries are [top, bottom) and [left, right).
+     *
+     * @param top    Top row index (inclusive).
+     * @param bottom Bottom row index (exclusive).
+     * @param left   Left column index (inclusive).
+     * @param right  Right column index (exclusive).
+     * @return The sum of the submatrix.
+     */
+    public int query(int top, int bottom, int left, int right) {
+        return query(top, bottom, left, right, 0, 0, n);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/SegmentTree2DTest.java b/src/test/java/com/thealgorithms/datastructures/trees/SegmentTree2DTest.java
new file mode 100644
index 000000000000..db081da2550a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/SegmentTree2DTest.java
@@ -0,0 +1,71 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class SegmentTree2DTest {
+
+    @Test
+    void testInitialEmptyQueries() {
+        SegmentTree2D segmentTree = new SegmentTree2D(4, 4);
+
+        // Initial tree should return 0 for any query
+        assertEquals(0, segmentTree.query(0, 4, 0, 4));
+        assertEquals(0, segmentTree.query(1, 3, 1, 3));
+    }
+
+    @Test
+    void testUpdateAndPointQuery() {
+        SegmentTree2D segmentTree = new SegmentTree2D(5, 5);
+
+        segmentTree.update(2, 3, 10);
+        segmentTree.update(0, 0, 5);
+
+        // Querying single points [row, row+1) x [col, col+1)
+        assertEquals(10, segmentTree.query(2, 3, 3, 4));
+        assertEquals(5, segmentTree.query(0, 1, 0, 1));
+
+        // Empty point should be 0
+        assertEquals(0, segmentTree.query(1, 2, 1, 2));
+    }
+
+    @Test
+    void testSubmatrixQuery() {
+        SegmentTree2D segmentTree = new SegmentTree2D(4, 4);
+
+        // Matrix simulation:
+        // [1, 2, 0, 0]
+        // [3, 4, 0, 0]
+        // [0, 0, 0, 0]
+        // [0, 0, 0, 0]
+        segmentTree.update(0, 0, 1);
+        segmentTree.update(0, 1, 2);
+        segmentTree.update(1, 0, 3);
+        segmentTree.update(1, 1, 4);
+
+        // Top-left 2x2 sum: 1+2+3+4 = 10
+        assertEquals(10, segmentTree.query(0, 2, 0, 2));
+
+        // First row sum: 1+2 = 3
+        assertEquals(3, segmentTree.query(0, 1, 0, 4));
+
+        // Second column sum: 2+4 = 6
+        assertEquals(6, segmentTree.query(0, 4, 1, 2));
+    }
+
+    @Test
+    void testUpdateOverwriting() {
+        SegmentTree2D segmentTree = new SegmentTree2D(3, 3);
+
+        segmentTree.update(1, 1, 5);
+        assertEquals(5, segmentTree.query(1, 2, 1, 2));
+
+        // Overwrite the same point
+        segmentTree.update(1, 1, 20);
+        assertEquals(20, segmentTree.query(1, 2, 1, 2));
+
+        // Full matrix sum should just be this point
+        assertEquals(20, segmentTree.query(0, 3, 0, 3));
+    }
+}

From 7eea9a5101a2347e4bb69e9ae2bc96b1fbd5cef4 Mon Sep 17 00:00:00 2001
From: kadambari25 <sureshkadambari62@gmail.com>
Date: Mon, 6 Apr 2026 21:40:34 +0200
Subject: [PATCH 1238/1338] Fix: handle null key in IterativeBinarySearch
 (#7365)

* Fix: handle null key in IterativeBinarySearch

* style: fix indentation in IterativeBinarySearch

* style: fix indentation in IterativeBinarySearch

---------

Co-authored-by: Kadambari <kadambari179@gmail.com>
---
 .../java/com/thealgorithms/searches/IterativeBinarySearch.java  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java b/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
index cc0bfb16d26c..d051dbc7b823 100644
--- a/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/IterativeBinarySearch.java
@@ -33,7 +33,7 @@ public final class IterativeBinarySearch implements SearchAlgorithm {
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
-        if (array == null || array.length == 0) {
+        if (array == null || array.length == 0 || key == null) {
             return -1;
         }
 

From 49f9e1a5a7c041a6b40db52b089b480e897b89b5 Mon Sep 17 00:00:00 2001
From: kadambari25 <sureshkadambari62@gmail.com>
Date: Wed, 8 Apr 2026 09:10:19 +0200
Subject: [PATCH 1239/1338] Improve readability in LinearSearch by using local
 variable (#7367)

Co-authored-by: Kadambari <kadambari179@gmail.com>
---
 src/main/java/com/thealgorithms/searches/LinearSearch.java | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/LinearSearch.java b/src/main/java/com/thealgorithms/searches/LinearSearch.java
index 77ecece3aaef..3f273e167f0a 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearch.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearch.java
@@ -51,7 +51,8 @@ public <T extends Comparable<T>> int find(T[] array, T value) {
         }
 
         for (int i = 0; i < array.length; i++) {
-            if (array[i] != null && array[i].compareTo(value) == 0) {
+            T currentElement = array[i];
+            if (currentElement != null && currentElement.compareTo(value) == 0) {
                 return i;
             }
         }

From 5b9db677b3fc3f081ad164a2657f018aa578b47f Mon Sep 17 00:00:00 2001
From: Feliphe Jesus <felseje@hotmail.com>
Date: Fri, 10 Apr 2026 17:21:48 -0300
Subject: [PATCH 1240/1338] Refactor Alphabetical implementation and tests
 (#7370)

* Improve Alphabetical implementation, tests and documentation

* Workaround SpotBugs false positive in parameterized tests

Replaced boolean literals with Boolean.TRUE/FALSE in Arguments.of(...)
to avoid SpotBugs warning (NAB_NEEDLESS_BOOLEAN_CONSTANT_CONVERSION).

This is a false positive caused by JUnit's Object... varargs
requiring auto-boxing.
---
 .../thealgorithms/strings/Alphabetical.java   | 52 ++++++++++++++-----
 .../strings/AlphabeticalTest.java             | 42 ++++++++++++---
 2 files changed, 75 insertions(+), 19 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/Alphabetical.java b/src/main/java/com/thealgorithms/strings/Alphabetical.java
index ef2974eb427d..37b1fb068b44 100644
--- a/src/main/java/com/thealgorithms/strings/Alphabetical.java
+++ b/src/main/java/com/thealgorithms/strings/Alphabetical.java
@@ -1,32 +1,58 @@
 package com.thealgorithms.strings;
 
+import java.util.Locale;
+
 /**
- * Utility class for checking if a string's characters are in alphabetical order.
+ * Utility class for checking whether a string's characters are in non-decreasing
+ * lexicographical order based on Unicode code points (case-insensitive).
+ * <p>
+ * This does NOT implement language-aware alphabetical ordering (collation rules).
+ * It simply compares lowercase Unicode character values.
  * <p>
- * Alphabetical order is a system whereby character strings are placed in order
- * based on the position of the characters in the conventional ordering of an
- * alphabet.
+ * Non-letter characters are not allowed and will cause the check to fail.
  * <p>
- * Reference: <a href="https://en.wikipedia.org/wiki/Alphabetical_order">Wikipedia: Alphabetical Order</a>
+ * Reference:
+ * <a href="https://en.wikipedia.org/wiki/Alphabetical_order">Wikipedia: Alphabetical order</a>
  */
 public final class Alphabetical {
+
     private Alphabetical() {
     }
 
     /**
-     * Checks whether the characters in the given string are in alphabetical order.
-     * Non-letter characters will cause the check to fail.
+     * Checks whether the characters in the given string are in non-decreasing
+     * lexicographical order (case-insensitive).
+     * <p>
+     * Rules:
+     * <ul>
+     *   <li>String must not be null or blank</li>
+     *   <li>All characters must be letters</li>
+     *   <li>Comparison is based on lowercase Unicode values</li>
+     *   <li>Order must be non-decreasing (equal or increasing allowed)</li>
+     * </ul>
      *
-     * @param s the input string
-     * @return {@code true} if all characters are in alphabetical order (case-insensitive), otherwise {@code false}
+     * @param s input string
+     * @return {@code true} if characters are in non-decreasing order, otherwise {@code false}
      */
     public static boolean isAlphabetical(String s) {
-        s = s.toLowerCase();
-        for (int i = 0; i < s.length() - 1; ++i) {
-            if (!Character.isLetter(s.charAt(i)) || s.charAt(i) > s.charAt(i + 1)) {
+        if (s == null || s.isBlank()) {
+            return false;
+        }
+
+        String normalized = s.toLowerCase(Locale.ROOT);
+
+        if (!Character.isLetter(normalized.charAt(0))) {
+            return false;
+        }
+
+        for (int i = 1; i < normalized.length(); i++) {
+            char prev = normalized.charAt(i - 1);
+            char curr = normalized.charAt(i);
+
+            if (!Character.isLetter(curr) || prev > curr) {
                 return false;
             }
         }
-        return !s.isEmpty() && Character.isLetter(s.charAt(s.length() - 1));
+        return true;
     }
 }
diff --git a/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java b/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java
index 7b41e11ef22f..0c7d7e4701cf 100644
--- a/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java
+++ b/src/test/java/com/thealgorithms/strings/AlphabeticalTest.java
@@ -1,15 +1,45 @@
 package com.thealgorithms.strings;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.params.provider.Arguments.arguments;
 
+import java.util.stream.Stream;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
-public class AlphabeticalTest {
+@DisplayName("Alphabetical.isAlphabetical()")
+class AlphabeticalTest {
 
-    @ParameterizedTest(name = "\"{0}\" → Expected: {1}")
-    @CsvSource({"'abcdefghijklmno', true", "'abcdxxxyzzzz', true", "'123a', false", "'abcABC', false", "'abcdefghikjlmno', false", "'aBC', true", "'abc', true", "'xyzabc', false", "'abcxyz', true", "'', false", "'1', false"})
-    void testIsAlphabetical(String input, boolean expected) {
-        assertEquals(expected, Alphabetical.isAlphabetical(input));
+    static Stream<Arguments> testCases() {
+        // Workaround for SpotBugs false positive (NAB_NEEDLESS_BOOLEAN_CONSTANT_CONVERSION)
+        // due to JUnit Arguments.of(Object...) auto-boxing
+        return Stream.of(arguments("", Boolean.FALSE, "Should return false for empty string"), arguments("   ", Boolean.FALSE, "Should return false for blank string"), arguments("a1b2", Boolean.FALSE, "Should return false when string contains numbers"),
+            arguments("abc!DEF", Boolean.FALSE, "Should return false when string contains symbols"), arguments("#abc", Boolean.FALSE, "Should return false when first character is not a letter"), arguments("abc", Boolean.TRUE, "Should return true for non-decreasing order"),
+            arguments("aBcD", Boolean.TRUE, "Should return true for mixed case increasing sequence"), arguments("a", Boolean.TRUE, "Should return true for single letter"), arguments("'", Boolean.FALSE, "Should return false for single symbol"),
+            arguments("aabbcc", Boolean.TRUE, "Should return true for repeated letters"), arguments("cba", Boolean.FALSE, "Should return false when order decreases"), arguments("abzba", Boolean.FALSE, "Should return false when middle breaks order"));
+    }
+
+    private void assertAlphabetical(String input, boolean expected, String message) {
+        // Arrange & Act
+        boolean result = Alphabetical.isAlphabetical(input);
+
+        // Assert
+        assertEquals(expected, result, message);
+    }
+
+    @Test
+    @DisplayName("Should return false for null input")
+    void nullInputTest() {
+        assertAlphabetical(null, false, "Should return false for null input");
+    }
+
+    @ParameterizedTest(name = "{2}")
+    @MethodSource("testCases")
+    @DisplayName("Alphabetical cases")
+    void isAlphabeticalTest(String input, boolean expected, String message) {
+        assertAlphabetical(input, expected, message);
     }
 }

From e0a7223ab40f66a87ce4e02a7b4aeca4302902ef Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 11 Apr 2026 09:34:54 +0200
Subject: [PATCH 1241/1338] chore(deps): bump actions/github-script from 8 to 9
 in /.github/workflows (#7371)

chore(deps): bump actions/github-script in /.github/workflows

Bumps [actions/github-script](https://github.com/actions/github-script) from 8 to 9.
- [Release notes](https://github.com/actions/github-script/releases)
- [Commits](https://github.com/actions/github-script/compare/v8...v9)

---
updated-dependencies:
- dependency-name: actions/github-script
  dependency-version: '9'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/close-failed-prs.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/close-failed-prs.yml b/.github/workflows/close-failed-prs.yml
index 6deea88f0daf..4013e87b6569 100644
--- a/.github/workflows/close-failed-prs.yml
+++ b/.github/workflows/close-failed-prs.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Close stale PRs
-        uses: actions/github-script@v8
+        uses: actions/github-script@v9
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |

From 1edf319cb3da42c75ac7c5cfeaf1928d409d9153 Mon Sep 17 00:00:00 2001
From: Papichardog <pablopichardogalindo@gmail.com>
Date: Sat, 11 Apr 2026 05:04:33 -0600
Subject: [PATCH 1242/1338] feat(maths): enhance Average with stream method and
 improved JavaDoc (#7369)

* docs(maths): improve JavaDoc for Average utility class

* feat(maths): add stream-based averageStream method and validations

* style: fix formatting

* style: final formatting fix for CI checks

* style: apply official clang-format to Average.java
---
 .../java/com/thealgorithms/maths/Average.java | 50 +++++++++++++++----
 1 file changed, 40 insertions(+), 10 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Average.java b/src/main/java/com/thealgorithms/maths/Average.java
index a550a7f6504d..cf55af509ccc 100644
--- a/src/main/java/com/thealgorithms/maths/Average.java
+++ b/src/main/java/com/thealgorithms/maths/Average.java
@@ -1,9 +1,16 @@
 package com.thealgorithms.maths;
 
+import java.util.Arrays;
+import java.util.OptionalDouble;
+
 /**
  * A utility class for computing the average of numeric arrays.
- * This class provides static methods to calculate the average of arrays
- * of both {@code double} and {@code int} values.
+ *
+ * <p>This class provides static methods to calculate the arithmetic mean
+ * of arrays of both {@code double} and {@code int} values. It also offers
+ * a Stream-based alternative for modern, declarative usage.
+ *
+ * <p>All methods guard against {@code null} or empty inputs.
  */
 public final class Average {
 
@@ -13,11 +20,14 @@ private Average() {
     }
 
     /**
-     * Computes the average of a {@code double} array.
+     * Computes the arithmetic mean of a {@code double} array.
+     *
+     * <p>The average is calculated as the sum of all elements divided
+     * by the number of elements: {@code avg = Σ(numbers[i]) / n}.
      *
-     * @param numbers an array of {@code double} values
-     * @return the average of the given numbers
-     * @throws IllegalArgumentException if the input array is {@code null} or empty
+     * @param numbers a non-null, non-empty array of {@code double} values
+     * @return the arithmetic mean of the given numbers
+     * @throws IllegalArgumentException if {@code numbers} is {@code null} or empty
      */
     public static double average(double[] numbers) {
         if (numbers == null || numbers.length == 0) {
@@ -31,11 +41,14 @@ public static double average(double[] numbers) {
     }
 
     /**
-     * Computes the average of an {@code int} array.
+     * Computes the arithmetic mean of an {@code int} array.
+     *
+     * <p>The sum is accumulated in a {@code long} to prevent integer overflow
+     * when processing large arrays or large values.
      *
-     * @param numbers an array of {@code int} values
-     * @return the average of the given numbers
-     * @throws IllegalArgumentException if the input array is {@code null} or empty
+     * @param numbers a non-null, non-empty array of {@code int} values
+     * @return the arithmetic mean as a {@code long} (truncated toward zero)
+     * @throws IllegalArgumentException if {@code numbers} is {@code null} or empty
      */
     public static long average(int[] numbers) {
         if (numbers == null || numbers.length == 0) {
@@ -47,4 +60,21 @@ public static long average(int[] numbers) {
         }
         return sum / numbers.length;
     }
+
+    /**
+     * Computes the arithmetic mean of a {@code double} array using Java Streams.
+     *
+     * <p>This method is a declarative alternative to {@link #average(double[])}.
+     * Instead of throwing on empty input, it returns an empty {@link OptionalDouble},
+     * following the convention of the Stream API.
+     *
+     * @param numbers an array of {@code double} values, may be {@code null} or empty
+     * @return an {@link OptionalDouble} with the mean, or empty if input is null/empty
+     */
+    public static OptionalDouble averageStream(double[] numbers) {
+        if (numbers == null || numbers.length == 0) {
+            return OptionalDouble.empty();
+        }
+        return Arrays.stream(numbers).average();
+    }
 }

From 79bc6201358862fd14fd13307b2bc52fcd89b201 Mon Sep 17 00:00:00 2001
From: Nick Zerjeski <57059725+nickzerjeski@users.noreply.github.com>
Date: Mon, 13 Apr 2026 13:02:04 +0200
Subject: [PATCH 1243/1338] feat(geometry): add line segment intersection
 utility (#7376)

* feat(geometry): add line segment intersection utility

* test(geometry): cover more line intersection edge cases

* Address line intersection edge cases from review

* Apply clang-format fixes for line intersection
---
 .../geometry/LineIntersection.java            | 105 ++++++++++++++++++
 .../geometry/LineIntersectionTest.java        | 101 +++++++++++++++++
 2 files changed, 206 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/geometry/LineIntersection.java
 create mode 100644 src/test/java/com/thealgorithms/geometry/LineIntersectionTest.java

diff --git a/src/main/java/com/thealgorithms/geometry/LineIntersection.java b/src/main/java/com/thealgorithms/geometry/LineIntersection.java
new file mode 100644
index 000000000000..8d65833816b3
--- /dev/null
+++ b/src/main/java/com/thealgorithms/geometry/LineIntersection.java
@@ -0,0 +1,105 @@
+package com.thealgorithms.geometry;
+
+import java.awt.geom.Point2D;
+import java.util.Optional;
+
+/**
+ * Utility methods for checking and computing 2D line segment intersections.
+ */
+public final class LineIntersection {
+    private LineIntersection() {
+    }
+
+    /**
+     * Checks whether two line segments intersect.
+     *
+     * @param p1 first endpoint of segment 1
+     * @param p2 second endpoint of segment 1
+     * @param q1 first endpoint of segment 2
+     * @param q2 second endpoint of segment 2
+     * @return true when the segments intersect (including touching endpoints)
+     */
+    public static boolean intersects(Point p1, Point p2, Point q1, Point q2) {
+        int o1 = orientation(p1, p2, q1);
+        int o2 = orientation(p1, p2, q2);
+        int o3 = orientation(q1, q2, p1);
+        int o4 = orientation(q1, q2, p2);
+
+        if (o1 != o2 && o3 != o4) {
+            return true;
+        }
+
+        if (o1 == 0 && onSegment(p1, q1, p2)) {
+            return true;
+        }
+        if (o2 == 0 && onSegment(p1, q2, p2)) {
+            return true;
+        }
+        if (o3 == 0 && onSegment(q1, p1, q2)) {
+            return true;
+        }
+        if (o4 == 0 && onSegment(q1, p2, q2)) {
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Computes the single geometric intersection point between two non-parallel
+     * segments when it exists.
+     *
+     * <p>For parallel/collinear overlap, this method returns {@code Optional.empty()}.
+     *
+     * @param p1 first endpoint of segment 1
+     * @param p2 second endpoint of segment 1
+     * @param q1 first endpoint of segment 2
+     * @param q2 second endpoint of segment 2
+     * @return the intersection point when uniquely defined and on both segments
+     */
+    public static Optional<Point2D.Double> intersectionPoint(Point p1, Point p2, Point q1, Point q2) {
+        if (!intersects(p1, p2, q1, q2)) {
+            return Optional.empty();
+        }
+
+        long x1 = p1.x();
+        long y1 = p1.y();
+        long x2 = p2.x();
+        long y2 = p2.y();
+        long x3 = q1.x();
+        long y3 = q1.y();
+        long x4 = q2.x();
+        long y4 = q2.y();
+
+        long denominator = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);
+        if (denominator == 0L) {
+            return sharedEndpoint(p1, p2, q1, q2);
+        }
+
+        long determinant1 = x1 * y2 - y1 * x2;
+        long determinant2 = x3 * y4 - y3 * x4;
+        long numeratorX = determinant1 * (x3 - x4) - (x1 - x2) * determinant2;
+        long numeratorY = determinant1 * (y3 - y4) - (y1 - y2) * determinant2;
+
+        return Optional.of(new Point2D.Double(numeratorX / (double) denominator, numeratorY / (double) denominator));
+    }
+
+    private static int orientation(Point a, Point b, Point c) {
+        long cross = ((long) b.x() - a.x()) * ((long) c.y() - a.y()) - ((long) b.y() - a.y()) * ((long) c.x() - a.x());
+        return Long.compare(cross, 0L);
+    }
+
+    private static Optional<Point2D.Double> sharedEndpoint(Point p1, Point p2, Point q1, Point q2) {
+        if (p1.equals(q1) || p1.equals(q2)) {
+            return Optional.of(new Point2D.Double(p1.x(), p1.y()));
+        }
+        if (p2.equals(q1) || p2.equals(q2)) {
+            return Optional.of(new Point2D.Double(p2.x(), p2.y()));
+        }
+        return Optional.empty();
+    }
+
+    private static boolean onSegment(Point a, Point b, Point c) {
+        return b.x() >= Math.min(a.x(), c.x()) && b.x() <= Math.max(a.x(), c.x()) && b.y() >= Math.min(a.y(), c.y()) && b.y() <= Math.max(a.y(), c.y());
+    }
+}
diff --git a/src/test/java/com/thealgorithms/geometry/LineIntersectionTest.java b/src/test/java/com/thealgorithms/geometry/LineIntersectionTest.java
new file mode 100644
index 000000000000..9f60df51b65f
--- /dev/null
+++ b/src/test/java/com/thealgorithms/geometry/LineIntersectionTest.java
@@ -0,0 +1,101 @@
+package com.thealgorithms.geometry;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.awt.geom.Point2D;
+import java.util.Optional;
+import org.junit.jupiter.api.Test;
+
+class LineIntersectionTest {
+
+    @Test
+    void testCrossingSegments() {
+        Point p1 = new Point(0, 0);
+        Point p2 = new Point(4, 4);
+        Point q1 = new Point(0, 4);
+        Point q2 = new Point(4, 0);
+
+        assertTrue(LineIntersection.intersects(p1, p2, q1, q2));
+        Optional<Point2D.Double> intersection = LineIntersection.intersectionPoint(p1, p2, q1, q2);
+        assertTrue(intersection.isPresent());
+        assertEquals(2.0, intersection.orElseThrow().getX(), 1e-9);
+        assertEquals(2.0, intersection.orElseThrow().getY(), 1e-9);
+    }
+
+    @Test
+    void testParallelSegments() {
+        Point p1 = new Point(0, 0);
+        Point p2 = new Point(3, 3);
+        Point q1 = new Point(0, 1);
+        Point q2 = new Point(3, 4);
+
+        assertFalse(LineIntersection.intersects(p1, p2, q1, q2));
+        assertTrue(LineIntersection.intersectionPoint(p1, p2, q1, q2).isEmpty());
+    }
+
+    @Test
+    void testTouchingAtEndpoint() {
+        Point p1 = new Point(0, 0);
+        Point p2 = new Point(2, 2);
+        Point q1 = new Point(2, 2);
+        Point q2 = new Point(4, 0);
+
+        assertTrue(LineIntersection.intersects(p1, p2, q1, q2));
+        Optional<Point2D.Double> intersection = LineIntersection.intersectionPoint(p1, p2, q1, q2);
+        assertTrue(intersection.isPresent());
+        assertEquals(2.0, intersection.orElseThrow().getX(), 1e-9);
+        assertEquals(2.0, intersection.orElseThrow().getY(), 1e-9);
+    }
+
+    @Test
+    void testCollinearOverlapHasNoUniquePoint() {
+        Point p1 = new Point(0, 0);
+        Point p2 = new Point(4, 4);
+        Point q1 = new Point(2, 2);
+        Point q2 = new Point(6, 6);
+
+        assertTrue(LineIntersection.intersects(p1, p2, q1, q2));
+        assertTrue(LineIntersection.intersectionPoint(p1, p2, q1, q2).isEmpty());
+    }
+
+    @Test
+    void testCollinearDisjointSegments() {
+        Point p1 = new Point(0, 0);
+        Point p2 = new Point(2, 2);
+        Point q1 = new Point(3, 3);
+        Point q2 = new Point(5, 5);
+
+        assertFalse(LineIntersection.intersects(p1, p2, q1, q2));
+        assertTrue(LineIntersection.intersectionPoint(p1, p2, q1, q2).isEmpty());
+    }
+
+    @Test
+    void testCollinearSegmentsTouchingAtEndpointHaveUniquePoint() {
+        Point p1 = new Point(0, 0);
+        Point p2 = new Point(2, 2);
+        Point q1 = new Point(2, 2);
+        Point q2 = new Point(4, 4);
+
+        assertTrue(LineIntersection.intersects(p1, p2, q1, q2));
+        Optional<Point2D.Double> intersection = LineIntersection.intersectionPoint(p1, p2, q1, q2);
+        assertTrue(intersection.isPresent());
+        assertEquals(2.0, intersection.orElseThrow().getX(), 1e-9);
+        assertEquals(2.0, intersection.orElseThrow().getY(), 1e-9);
+    }
+
+    @Test
+    void testVerticalAndHorizontalCrossingSegments() {
+        Point p1 = new Point(2, 0);
+        Point p2 = new Point(2, 5);
+        Point q1 = new Point(0, 3);
+        Point q2 = new Point(4, 3);
+
+        assertTrue(LineIntersection.intersects(p1, p2, q1, q2));
+        Optional<Point2D.Double> intersection = LineIntersection.intersectionPoint(p1, p2, q1, q2);
+        assertTrue(intersection.isPresent());
+        assertEquals(2.0, intersection.orElseThrow().getX(), 1e-9);
+        assertEquals(3.0, intersection.orElseThrow().getY(), 1e-9);
+    }
+}

From df8fd850584077c8a15039301d52c9efd1400dbc Mon Sep 17 00:00:00 2001
From: Prashant Maurya <prashantpiyush1111@gmail.com>
Date: Tue, 14 Apr 2026 15:29:22 +0530
Subject: [PATCH 1244/1338] docs: add edge cases to JumpSearch documentation
 (#7379)

* docs: add edge cases to JumpSearch documentation

* fix: remove trailing whitespace (checkstyle)
---
 src/main/java/com/thealgorithms/searches/JumpSearch.java | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/main/java/com/thealgorithms/searches/JumpSearch.java b/src/main/java/com/thealgorithms/searches/JumpSearch.java
index cbc494c8c16a..5074aa7845c8 100644
--- a/src/main/java/com/thealgorithms/searches/JumpSearch.java
+++ b/src/main/java/com/thealgorithms/searches/JumpSearch.java
@@ -36,6 +36,13 @@
  * <b>Space Complexity:</b> O(1) - only uses a constant amount of extra space
  *
  * <p>
+ * <b>Edge Cases:</b>
+ * <ul>
+ *   <li>Empty array → returns -1</li>
+ *   <li>Element not present → returns -1</li>
+ *   <li>Single element array</li>
+ * </ul>
+ * <p>
  * <b>Note:</b> Jump Search requires a sorted array. For unsorted arrays, use Linear Search.
  * Compared to Linear Search (O(n)), Jump Search is faster for large arrays.
  * Compared to Binary Search (O(log n)), Jump Search is less efficient but may be

From 14b6f9924216e5e0c4c2c70683c930bac369c1b9 Mon Sep 17 00:00:00 2001
From: Nick Zerjeski <57059725+nickzerjeski@users.noreply.github.com>
Date: Tue, 14 Apr 2026 12:03:00 +0200
Subject: [PATCH 1245/1338] test(searches): cover null input cases in
 IterativeBinarySearch (#7375)

---
 .../searches/IterativeBinarySearchTest.java   | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java
index b2e121ac1ba0..f291610b298b 100644
--- a/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java
@@ -87,6 +87,26 @@ void testBinarySearchEmptyArray() {
         assertEquals(-1, binarySearch.find(array, key), "The element should not be found in an empty array.");
     }
 
+    /**
+     * Test for binary search with a null array.
+     */
+    @Test
+    void testBinarySearchNullArray() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer key = 1;
+        assertEquals(-1, binarySearch.find(null, key), "The element should not be found in a null array.");
+    }
+
+    /**
+     * Test for binary search with a null key.
+     */
+    @Test
+    void testBinarySearchNullKey() {
+        IterativeBinarySearch binarySearch = new IterativeBinarySearch();
+        Integer[] array = {1, 2, 4, 8, 16};
+        assertEquals(-1, binarySearch.find(array, null), "A null search key should return -1.");
+    }
+
     /**
      * Test for binary search on a large array.
      */

From b3e31b5a5cd1465e474b71d87b44d4659fcfda23 Mon Sep 17 00:00:00 2001
From: Nick Zerjeski <57059725+nickzerjeski@users.noreply.github.com>
Date: Wed, 15 Apr 2026 16:07:03 +0200
Subject: [PATCH 1246/1338] feat(graph): add DSU-based account merge algorithm
 (#7377)

* feat(graph): add DSU-based account merge algorithm

* test(graph): add null and transitive account merge cases

* Handle no-email accounts in account merge

* Apply clang-format style to account merge tests
---
 .../com/thealgorithms/graph/AccountMerge.java | 112 ++++++++++++++++++
 .../thealgorithms/graph/AccountMergeTest.java |  61 ++++++++++
 2 files changed, 173 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/graph/AccountMerge.java
 create mode 100644 src/test/java/com/thealgorithms/graph/AccountMergeTest.java

diff --git a/src/main/java/com/thealgorithms/graph/AccountMerge.java b/src/main/java/com/thealgorithms/graph/AccountMerge.java
new file mode 100644
index 000000000000..cf934a72eb68
--- /dev/null
+++ b/src/main/java/com/thealgorithms/graph/AccountMerge.java
@@ -0,0 +1,112 @@
+package com.thealgorithms.graph;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Merges account records using Disjoint Set Union (Union-Find) on shared emails.
+ *
+ * <p>Input format: each account is a list where the first element is the user name and the
+ * remaining elements are emails.
+ */
+public final class AccountMerge {
+    private AccountMerge() {
+    }
+
+    public static List<List<String>> mergeAccounts(List<List<String>> accounts) {
+        if (accounts == null || accounts.isEmpty()) {
+            return List.of();
+        }
+
+        UnionFind dsu = new UnionFind(accounts.size());
+        Map<String, Integer> emailToAccount = new HashMap<>();
+
+        for (int i = 0; i < accounts.size(); i++) {
+            List<String> account = accounts.get(i);
+            for (int j = 1; j < account.size(); j++) {
+                String email = account.get(j);
+                Integer previous = emailToAccount.putIfAbsent(email, i);
+                if (previous != null) {
+                    dsu.union(i, previous);
+                }
+            }
+        }
+
+        Map<Integer, List<String>> rootToEmails = new LinkedHashMap<>();
+        for (Map.Entry<String, Integer> entry : emailToAccount.entrySet()) {
+            int root = dsu.find(entry.getValue());
+            rootToEmails.computeIfAbsent(root, ignored -> new ArrayList<>()).add(entry.getKey());
+        }
+        for (int i = 0; i < accounts.size(); i++) {
+            if (accounts.get(i).size() <= 1) {
+                int root = dsu.find(i);
+                rootToEmails.computeIfAbsent(root, ignored -> new ArrayList<>());
+            }
+        }
+
+        List<List<String>> merged = new ArrayList<>();
+        for (Map.Entry<Integer, List<String>> entry : rootToEmails.entrySet()) {
+            int root = entry.getKey();
+            List<String> emails = entry.getValue();
+            Collections.sort(emails);
+
+            List<String> mergedAccount = new ArrayList<>();
+            mergedAccount.add(accounts.get(root).getFirst());
+            mergedAccount.addAll(emails);
+            merged.add(mergedAccount);
+        }
+
+        merged.sort((a, b) -> {
+            int cmp = a.getFirst().compareTo(b.getFirst());
+            if (cmp != 0) {
+                return cmp;
+            }
+            if (a.size() == 1 || b.size() == 1) {
+                return Integer.compare(a.size(), b.size());
+            }
+            return a.get(1).compareTo(b.get(1));
+        });
+        return merged;
+    }
+
+    private static final class UnionFind {
+        private final int[] parent;
+        private final int[] rank;
+
+        private UnionFind(int size) {
+            this.parent = new int[size];
+            this.rank = new int[size];
+            for (int i = 0; i < size; i++) {
+                parent[i] = i;
+            }
+        }
+
+        private int find(int x) {
+            if (parent[x] != x) {
+                parent[x] = find(parent[x]);
+            }
+            return parent[x];
+        }
+
+        private void union(int x, int y) {
+            int rootX = find(x);
+            int rootY = find(y);
+            if (rootX == rootY) {
+                return;
+            }
+
+            if (rank[rootX] < rank[rootY]) {
+                parent[rootX] = rootY;
+            } else if (rank[rootX] > rank[rootY]) {
+                parent[rootY] = rootX;
+            } else {
+                parent[rootY] = rootX;
+                rank[rootX]++;
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/graph/AccountMergeTest.java b/src/test/java/com/thealgorithms/graph/AccountMergeTest.java
new file mode 100644
index 000000000000..291be677d894
--- /dev/null
+++ b/src/test/java/com/thealgorithms/graph/AccountMergeTest.java
@@ -0,0 +1,61 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class AccountMergeTest {
+
+    @Test
+    void testMergeAccountsWithSharedEmails() {
+        List<List<String>> accounts = List.of(List.of("abc", "abc@mail.com", "abx@mail.com"), List.of("abc", "abc@mail.com", "aby@mail.com"), List.of("Mary", "mary@mail.com"), List.of("John", "johnnybravo@mail.com"));
+
+        List<List<String>> merged = AccountMerge.mergeAccounts(accounts);
+
+        List<List<String>> expected = List.of(List.of("John", "johnnybravo@mail.com"), List.of("Mary", "mary@mail.com"), List.of("abc", "abc@mail.com", "abx@mail.com", "aby@mail.com"));
+
+        assertEquals(expected, merged);
+    }
+
+    @Test
+    void testAccountsWithSameNameButNoSharedEmailStaySeparate() {
+        List<List<String>> accounts = List.of(List.of("Alex", "alex1@mail.com"), List.of("Alex", "alex2@mail.com"));
+
+        List<List<String>> merged = AccountMerge.mergeAccounts(accounts);
+        List<List<String>> expected = List.of(List.of("Alex", "alex1@mail.com"), List.of("Alex", "alex2@mail.com"));
+
+        assertEquals(expected, merged);
+    }
+
+    @Test
+    void testEmptyInput() {
+        assertEquals(List.of(), AccountMerge.mergeAccounts(List.of()));
+    }
+
+    @Test
+    void testNullInput() {
+        assertEquals(List.of(), AccountMerge.mergeAccounts(null));
+    }
+
+    @Test
+    void testTransitiveMergeAndDuplicateEmails() {
+        List<List<String>> accounts = List.of(List.of("A", "a1@mail.com", "a2@mail.com"), List.of("A", "a2@mail.com", "a3@mail.com"), List.of("A", "a3@mail.com", "a4@mail.com", "a4@mail.com"));
+
+        List<List<String>> merged = AccountMerge.mergeAccounts(accounts);
+
+        List<List<String>> expected = List.of(List.of("A", "a1@mail.com", "a2@mail.com", "a3@mail.com", "a4@mail.com"));
+
+        assertEquals(expected, merged);
+    }
+
+    @Test
+    void testAccountsWithNoEmailsArePreserved() {
+        List<List<String>> accounts = List.of(List.of("Alex"), List.of("Alex", "alex1@mail.com"), List.of("Bob"));
+
+        List<List<String>> merged = AccountMerge.mergeAccounts(accounts);
+        List<List<String>> expected = List.of(List.of("Alex"), List.of("Alex", "alex1@mail.com"), List.of("Bob"));
+
+        assertEquals(expected, merged);
+    }
+}

From 0ad5d90012095fc90f3fba4ec28560421f7e0844 Mon Sep 17 00:00:00 2001
From: Senrian <47714364+Senrian@users.noreply.github.com>
Date: Wed, 22 Apr 2026 17:26:20 +0800
Subject: [PATCH 1247/1338] fix: remove malformed javadoc to fix -Werror build
 failure (#7393) (#7394)

* fix: prevent NPE when array contains null elements

When searching for a non-null key in an array that contains null elements,
the sentinel linear search would throw a NullPointerException because it
called array[i].compareTo(key) without checking if array[i] is null.

Added null check for array[i] in the while loop condition to prevent NPE
and return the correct index when array elements themselves are null.

Issue: #7318 (related)

* fix: remove malformed @author javadoc in AnyBaseToAnyBase (issue #7393)

* fix: remove malformed javadoc in ReverseString (part of issue #7393)

---------

Co-authored-by: OpenClaw Agent <agent@openclaw.ai>
Co-authored-by: OpenClaw Bot <fix-bug@openclaw.ai>
Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../java/com/thealgorithms/conversions/AnyBaseToAnyBase.java   | 2 +-
 .../java/com/thealgorithms/searches/SentinelLinearSearch.java  | 3 ++-
 src/main/java/com/thealgorithms/strings/ReverseString.java     | 2 +-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
index 7698cc832981..3d31cb3e7f6c 100644
--- a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
+++ b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
@@ -3,7 +3,7 @@
  * <p>
  * Time Complexity: O(n) [or appropriate complexity]
  * Space Complexity: O(n)
- * * @author Reshma Kakkirala
+ * @author Reshma Kakkirala
  */
 package com.thealgorithms.conversions;
 
diff --git a/src/main/java/com/thealgorithms/searches/SentinelLinearSearch.java b/src/main/java/com/thealgorithms/searches/SentinelLinearSearch.java
index 1a5903a5d134..473fc2c3f094 100644
--- a/src/main/java/com/thealgorithms/searches/SentinelLinearSearch.java
+++ b/src/main/java/com/thealgorithms/searches/SentinelLinearSearch.java
@@ -65,7 +65,8 @@ public <T extends Comparable<T>> int find(T[] array, T key) {
 
         int i = 0;
         // Search without bound checking since sentinel guarantees we'll find the key
-        while (array[i].compareTo(key) != 0) {
+        // Null check for array element to prevent NPE when array contains null elements
+        while (array[i] != null && array[i].compareTo(key) != 0) {
             i++;
         }
 
diff --git a/src/main/java/com/thealgorithms/strings/ReverseString.java b/src/main/java/com/thealgorithms/strings/ReverseString.java
index 7b918ebe1a59..e373dd0b7174 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseString.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseString.java
@@ -62,7 +62,7 @@ public static String reverse3(String string) {
     /**
      * Reverses the given string using a stack.
      * This method uses a stack to reverse the characters of the string.
-     * * @param str The input string to be reversed.
+     * @param str The input string to be reversed.
      * @return The reversed string.
      */
     public static String reverseStringUsingStack(String str) {

From 763b95b69b33f790093d1eae3599dfcc47f2a4c7 Mon Sep 17 00:00:00 2001
From: orbisai0security <mediratta01.pally@gmail.com>
Date: Wed, 22 Apr 2026 22:53:28 +0530
Subject: [PATCH 1248/1338] fix: aesencryption in AESEncryption.java (#7392)

fix: V-001 security vulnerability

Automated security fix generated by Orbis Security AI
---
 src/main/java/com/thealgorithms/ciphers/AESEncryption.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/AESEncryption.java b/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
index 14582205442f..6f155e73f47d 100644
--- a/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
+++ b/src/main/java/com/thealgorithms/ciphers/AESEncryption.java
@@ -38,7 +38,7 @@ public static void main(String[] args) throws Exception {
         System.out.println("Original Text:" + plainText);
         System.out.println("AES Key (Hex Form):" + bytesToHex(secKey.getEncoded()));
         System.out.println("Encrypted Text (Hex Form):" + bytesToHex(cipherText));
-        System.out.println("Descrypted Text:" + decryptedText);
+        System.out.println("Decryption successful. Decrypted text matches original: " + decryptedText.equals(plainText));
     }
 
     /**

From 35b94ab4f8214b1a939ae504b7b83ed5d071625e Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 27 Apr 2026 20:42:24 +0200
Subject: [PATCH 1249/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.4.0 to 13.4.1 (#7404)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.4.0 to 13.4.1.
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.4.0...checkstyle-13.4.1)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.4.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 74b6cd9bd485..2a543a6549d0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.4.0</version>
+                    <version>13.4.1</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 6db8e207669e7f1b689615222e7ee54c68dc4981 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 2 May 2026 22:16:55 +0200
Subject: [PATCH 1250/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.4.1 to 13.4.2 (#7411)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.4.1 to 13.4.2.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.4.1...checkstyle-13.4.2)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.4.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 2a543a6549d0..e0a3486b23bb 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.4.1</version>
+                    <version>13.4.2</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 2616e0950feaa3ff2e4a1bc1d9e0530eb979e442 Mon Sep 17 00:00:00 2001
From: Abdul-Rehman-svg <aminabibi7622123@gmail.com>
Date: Sun, 3 May 2026 17:30:16 +0500
Subject: [PATCH 1251/1338] Update Anagrams.java (#7409)

fix: remove invalid reference [1] in Anagrams.java

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 src/main/java/com/thealgorithms/strings/Anagrams.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/strings/Anagrams.java b/src/main/java/com/thealgorithms/strings/Anagrams.java
index 5b97af0758f2..7bd84d47508f 100644
--- a/src/main/java/com/thealgorithms/strings/Anagrams.java
+++ b/src/main/java/com/thealgorithms/strings/Anagrams.java
@@ -5,7 +5,7 @@
 
 /**
  * An anagram is a word or phrase formed by rearranging the letters of a different word or phrase,
- * typically using all the original letters exactly once.[1]
+ * typically using all the original letters exactly once.
  * For example, the word anagram itself can be rearranged into nag a ram,
  * also the word binary into brainy and the word adobe into abode.
  * Reference from https://en.wikipedia.org/wiki/Anagram

From 54341c104e6ba307e61f538a9cf04ad3992cb656 Mon Sep 17 00:00:00 2001
From: Bhanu <144544908+Bhanubasyan@users.noreply.github.com>
Date: Sat, 9 May 2026 02:22:16 +0530
Subject: [PATCH 1252/1338] Optimized NQueens implementation using hashing
 (#7416)

* Optimized NQueens implementation using hashing

* Fixed checkstyle naming issues

* Fixed formatting issues

* Fixed operator wrap formatting

* Fixed formatting issues

* Fixed operator wrapping style

* Fixed print formatting

* Fixed print formatting

* Fixed operator formatting

* Removed extra brace
---
 .../thealgorithms/backtracking/NQueens.java   | 72 +++++++++++--------
 1 file changed, 44 insertions(+), 28 deletions(-)

diff --git a/src/main/java/com/thealgorithms/backtracking/NQueens.java b/src/main/java/com/thealgorithms/backtracking/NQueens.java
index 1a8e453e34cb..404f677738a0 100644
--- a/src/main/java/com/thealgorithms/backtracking/NQueens.java
+++ b/src/main/java/com/thealgorithms/backtracking/NQueens.java
@@ -1,7 +1,9 @@
 package com.thealgorithms.backtracking;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 /**
  * Problem statement: Given a N x N chess board. Return all arrangements in
@@ -32,7 +34,22 @@
  * queen is not placed safely. If there is no such way then return an empty list
  * as solution
  */
+
+/*
+ * Time Complexity: O(N!)
+ * space Complexity: O(N)
+ */
 public final class NQueens {
+
+    // Store occupied rows for constant time safety check
+    private static final Set<Integer> OCROWS = new HashSet<>();
+
+    // Store occupied main diagonals (row - column)
+    private static final Set<Integer> OCDIAG = new HashSet<>();
+
+    // Store occupied anti-diagonals (row + columns)
+    private static final Set<Integer> OCANTIDIAG = new HashSet<>();
+
     private NQueens() {
     }
 
@@ -43,10 +60,10 @@ public static List<List<String>> getNQueensArrangements(int queens) {
     }
 
     public static void placeQueens(final int queens) {
-        List<List<String>> arrangements = new ArrayList<List<String>>();
+        List<List<String>> arrangements = new ArrayList<>();
         getSolution(queens, arrangements, new int[queens], 0);
         if (arrangements.isEmpty()) {
-            System.out.println("There is no way to place " + queens + " queens on board of size " + queens + "x" + queens);
+            System.out.println(" no way to place " + queens + " queens on board of size " + queens + "x" + queens);
         } else {
             System.out.println("Arrangement for placing " + queens + " queens");
         }
@@ -59,15 +76,15 @@ public static void placeQueens(final int queens) {
     /**
      * This is backtracking function which tries to place queen recursively
      *
-     * @param boardSize: size of chess board
-     * @param solutions: this holds all possible arrangements
-     * @param columns: columns[i] = rowId where queen is placed in ith column.
+     * @param boardSize:   size of chess board
+     * @param solutions:   this holds all possible arrangements
+     * @param columns:     columns[i] = rowId where queen is placed in ith column.
      * @param columnIndex: This is the column in which queen is being placed
      */
     private static void getSolution(int boardSize, List<List<String>> solutions, int[] columns, int columnIndex) {
         if (columnIndex == boardSize) {
             // this means that all queens have been placed
-            List<String> sol = new ArrayList<String>();
+            List<String> sol = new ArrayList<>();
             for (int i = 0; i < boardSize; i++) {
                 StringBuilder sb = new StringBuilder();
                 for (int j = 0; j < boardSize; j++) {
@@ -82,30 +99,29 @@ private static void getSolution(int boardSize, List<List<String>> solutions, int
         // This loop tries to place queen in a row one by one
         for (int rowIndex = 0; rowIndex < boardSize; rowIndex++) {
             columns[columnIndex] = rowIndex;
-            if (isPlacedCorrectly(columns, rowIndex, columnIndex)) {
-                // If queen is placed successfully at rowIndex in column=columnIndex then try
-                // placing queen in next column
-                getSolution(boardSize, solutions, columns, columnIndex + 1);
-            }
-        }
-    }
 
-    /**
-     * This function checks if queen can be placed at row = rowIndex in column =
-     * columnIndex safely
-     *
-     * @param columns: columns[i] = rowId where queen is placed in ith column.
-     * @param rowIndex: row in which queen has to be placed
-     * @param columnIndex: column in which queen is being placed
-     * @return true: if queen can be placed safely false: otherwise
-     */
-    private static boolean isPlacedCorrectly(int[] columns, int rowIndex, int columnIndex) {
-        for (int i = 0; i < columnIndex; i++) {
-            int diff = Math.abs(columns[i] - rowIndex);
-            if (diff == 0 || columnIndex - i == diff) {
-                return false;
+            // Skip current position if row or diagonal is already occupied
+            boolean isROp = OCROWS.contains(rowIndex);
+
+            boolean isDOp = OCDIAG.contains(rowIndex - columnIndex) || OCANTIDIAG.contains(rowIndex + columnIndex);
+
+            if (isROp || isDOp) {
+                continue;
             }
+
+            // Mark current row and diagonal as occupied
+            OCROWS.add(rowIndex);
+            OCDIAG.add(rowIndex - columnIndex);
+            OCANTIDIAG.add(rowIndex + columnIndex);
+
+            // Move to the next column after placing current queen
+            getSolution(boardSize, solutions, columns, columnIndex + 1);
+
+            // Backtrack by removing current queen
+
+            OCROWS.remove(rowIndex);
+            OCDIAG.remove(rowIndex - columnIndex);
+            OCANTIDIAG.remove(rowIndex + columnIndex);
         }
-        return true;
     }
 }

From e814d97309e8fd5486671896d62ad149beef0f70 Mon Sep 17 00:00:00 2001
From: Shalini H R <shalinidvg16@gmail.com>
Date: Sat, 9 May 2026 20:53:49 +0530
Subject: [PATCH 1253/1338] Added null check to EMAFilter (#7417)

---
 .../com/thealgorithms/audiofilters/EMAFilter.java    | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/audiofilters/EMAFilter.java b/src/main/java/com/thealgorithms/audiofilters/EMAFilter.java
index 0dd23e937953..4a9e954bd202 100644
--- a/src/main/java/com/thealgorithms/audiofilters/EMAFilter.java
+++ b/src/main/java/com/thealgorithms/audiofilters/EMAFilter.java
@@ -3,16 +3,19 @@
 /**
  * Exponential Moving Average (EMA) Filter for smoothing audio signals.
  *
- * <p>This filter applies an exponential moving average to a sequence of audio
+ * <p>
+ * This filter applies an exponential moving average to a sequence of audio
  * signal values, making it useful for smoothing out rapid fluctuations.
  * The smoothing factor (alpha) controls the degree of smoothing.
  *
- * <p>Based on the definition from
+ * <p>
+ * Based on the definition from
  * <a href="https://en.wikipedia.org/wiki/Moving_average">Wikipedia link</a>.
  */
 public class EMAFilter {
     private final double alpha;
     private double emaValue;
+
     /**
      * Constructs an EMA filter with a given smoothing factor.
      *
@@ -26,14 +29,17 @@ public EMAFilter(double alpha) {
         this.alpha = alpha;
         this.emaValue = 0.0;
     }
+
     /**
      * Applies the EMA filter to an audio signal array.
+     * EMA formula:
+     * EMA = alpha * currentSample + (1 - alpha) * previousEMA
      *
      * @param audioSignal Array of audio samples to process
      * @return Array of processed (smoothed) samples
      */
     public double[] apply(double[] audioSignal) {
-        if (audioSignal.length == 0) {
+        if (audioSignal == null || audioSignal.length == 0) {
             return new double[0];
         }
         double[] emaSignal = new double[audioSignal.length];

From e7f8979192ee84006e3eead98d6f891111664c9a Mon Sep 17 00:00:00 2001
From: Sunny Sharma <119731813+the-Sunny-Sharma@users.noreply.github.com>
Date: Thu, 14 May 2026 02:17:00 +0530
Subject: [PATCH 1254/1338] feat: add Rat in a Maze backtracking algorithm
 (#7418)

* feat: add Rat in a Maze backtracking algorithm with 10 unit tests

* test: add coverage for all-open maze and larger maze path

* style: apply clang-format fixes and add newline at end of files

* style: apply clang-format and checkstyle fixes
---
 .../backtracking/RatInAMaze.java              | 119 ++++++++++++++++++
 .../backtracking/RatInAMazeTest.java          |  99 +++++++++++++++
 2 files changed, 218 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/backtracking/RatInAMaze.java
 create mode 100644 src/test/java/com/thealgorithms/backtracking/RatInAMazeTest.java

diff --git a/src/main/java/com/thealgorithms/backtracking/RatInAMaze.java b/src/main/java/com/thealgorithms/backtracking/RatInAMaze.java
new file mode 100644
index 000000000000..183b4bbd97f8
--- /dev/null
+++ b/src/main/java/com/thealgorithms/backtracking/RatInAMaze.java
@@ -0,0 +1,119 @@
+package com.thealgorithms.backtracking;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Rat in a Maze Problem using Backtracking.
+ *
+ * <p>Given an {@code n x n} binary maze where {@code 1} represents an open cell
+ * and {@code 0} represents a blocked cell, find all paths for a rat starting at
+ * the top-left cell {@code (0, 0)} to reach the bottom-right cell {@code (n-1, n-1)}.
+ *
+ * <p>The rat can move in four directions: Up (U), Down (D), Left (L), Right (R).
+ * Each cell may be visited at most once per path.
+ *
+ * <p>Time Complexity: O(4^(n²)) in the worst case (four choices per cell).
+ * Space Complexity: O(n²) for the visited matrix and recursion stack.
+ *
+ * <p>Example:
+ * <pre>
+ *   maze = { {1, 0, 0, 0},
+ *            {1, 1, 0, 1},
+ *            {0, 1, 0, 0},
+ *            {0, 1, 1, 1} }
+ *   Output: ["DDRDRR", "DRDDRR"]  (two valid paths)
+ * </pre>
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Maze_solving_algorithm">Maze solving algorithm</a>
+ * @author the-Sunny-Sharma (<a href="https://github.com/the-Sunny-Sharma">GitHub</a>)
+ */
+public final class RatInAMaze {
+
+    private RatInAMaze() {
+    }
+
+    /**
+     * Finds all paths from the top-left to the bottom-right of the given maze.
+     *
+     * @param maze an {@code n x n} binary matrix where {@code 1} = open, {@code 0} = blocked
+     * @return a sorted list of all valid path strings using directions D, L, R, U;
+     *         an empty list if no path exists
+     * @throws IllegalArgumentException if the maze is null, empty, or not square
+     */
+    public static List<String> findPaths(final int[][] maze) {
+        if (maze == null || maze.length == 0) {
+            throw new IllegalArgumentException("Maze must not be null or empty.");
+        }
+        int n = maze.length;
+        for (int[] row : maze) {
+            if (row.length != n) {
+                throw new IllegalArgumentException("Maze must be a square (n x n) matrix.");
+            }
+        }
+        List<String> results = new ArrayList<>();
+        if (maze[0][0] == 0 || maze[n - 1][n - 1] == 0) {
+            return results;
+        }
+        boolean[][] visited = new boolean[n][n];
+        solve(maze, 0, 0, n, "", visited, results);
+        return results;
+    }
+
+    /**
+     * Recursive backtracking helper that explores all four directions.
+     *
+     * @param maze    the binary maze
+     * @param row     current row position
+     * @param col     current column position
+     * @param n       maze dimension
+     * @param path    path string built so far
+     * @param visited tracks visited cells for the current path
+     * @param results accumulates complete paths
+     */
+    private static void solve(final int[][] maze, final int row, final int col, final int n, final String path, final boolean[][] visited, final List<String> results) {
+        // Base case: reached destination
+        if (row == n - 1 && col == n - 1) {
+            results.add(path);
+            return;
+        }
+
+        // Mark current cell as visited
+        visited[row][col] = true;
+
+        // Explore in alphabetical order: Down, Left, Right, Up
+        // Down
+        if (isSafe(maze, row + 1, col, n, visited)) {
+            solve(maze, row + 1, col, n, path + 'D', visited, results);
+        }
+        // Left
+        if (isSafe(maze, row, col - 1, n, visited)) {
+            solve(maze, row, col - 1, n, path + 'L', visited, results);
+        }
+        // Right
+        if (isSafe(maze, row, col + 1, n, visited)) {
+            solve(maze, row, col + 1, n, path + 'R', visited, results);
+        }
+        // Up
+        if (isSafe(maze, row - 1, col, n, visited)) {
+            solve(maze, row - 1, col, n, path + 'U', visited, results);
+        }
+
+        // Backtrack: unmark current cell
+        visited[row][col] = false;
+    }
+
+    /**
+     * Checks whether moving to {@code (row, col)} is valid.
+     *
+     * @param maze    the binary maze
+     * @param row     target row
+     * @param col     target column
+     * @param n       maze dimension
+     * @param visited tracks visited cells for the current path
+     * @return {@code true} if the cell is within bounds, open, and not yet visited
+     */
+    private static boolean isSafe(final int[][] maze, final int row, final int col, final int n, final boolean[][] visited) {
+        return row >= 0 && row < n && col >= 0 && col < n && maze[row][col] == 1 && !visited[row][col];
+    }
+}
diff --git a/src/test/java/com/thealgorithms/backtracking/RatInAMazeTest.java b/src/test/java/com/thealgorithms/backtracking/RatInAMazeTest.java
new file mode 100644
index 000000000000..ecd1f3c4dfae
--- /dev/null
+++ b/src/test/java/com/thealgorithms/backtracking/RatInAMazeTest.java
@@ -0,0 +1,99 @@
+package com.thealgorithms.backtracking;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class RatInAMazeTest {
+
+    @Test
+    void testMultiplePathsExist() {
+        int[][] maze = {{1, 0, 0, 0}, {1, 1, 0, 1}, {0, 1, 0, 0}, {0, 1, 1, 1}};
+
+        List<String> paths = RatInAMaze.findPaths(maze);
+        assertTrue(paths.size() >= 1);
+        for (String path : paths) {
+            assertTrue(path.chars().allMatch(c -> "DLRU".indexOf(c) >= 0));
+        }
+    }
+
+    @Test
+    void testSinglePath() {
+        int[][] maze = {{1, 0, 0}, {1, 1, 0}, {0, 1, 1}};
+        List<String> paths = RatInAMaze.findPaths(maze);
+        assertEquals(1, paths.size());
+        assertEquals("DRDR", paths.get(0));
+    }
+
+    @Test
+    void testNoPathExists() {
+        int[][] maze = {{1, 0, 0}, {0, 0, 0}, {0, 0, 1}};
+        List<String> paths = RatInAMaze.findPaths(maze);
+        assertTrue(paths.isEmpty());
+    }
+
+    @Test
+    void testSourceBlocked() {
+        int[][] maze = {{0, 1}, {1, 1}};
+        List<String> paths = RatInAMaze.findPaths(maze);
+        assertTrue(paths.isEmpty());
+    }
+
+    @Test
+    void testDestinationBlocked() {
+        int[][] maze = {{1, 1}, {1, 0}};
+        List<String> paths = RatInAMaze.findPaths(maze);
+        assertTrue(paths.isEmpty());
+    }
+
+    @Test
+    void testSingleCellMazeOpen() {
+        int[][] maze = {{1}};
+        List<String> paths = RatInAMaze.findPaths(maze);
+        assertEquals(1, paths.size());
+        assertEquals("", paths.get(0));
+    }
+
+    @Test
+    void testSingleCellMazeBlocked() {
+        int[][] maze = {{0}};
+        List<String> paths = RatInAMaze.findPaths(maze);
+        assertTrue(paths.isEmpty());
+    }
+
+    @Test
+    void testNullMazeThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> RatInAMaze.findPaths(null));
+    }
+
+    @Test
+    void testEmptyMazeThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> RatInAMaze.findPaths(new int[][] {}));
+    }
+
+    @Test
+    void testNonSquareMazeThrowsException() {
+        int[][] maze = {{1, 0, 1}, {1, 1, 1}};
+        assertThrows(IllegalArgumentException.class, () -> RatInAMaze.findPaths(maze));
+    }
+
+    @Test
+    void testAllCellsOpen() {
+        int[][] maze = {{1, 1, 1}, {1, 1, 1}, {1, 1, 1}};
+        List<String> paths = RatInAMaze.findPaths(maze);
+        assertTrue(paths.size() > 1);
+    }
+
+    @Test
+    void testLargerMazeWithPath() {
+        int[][] maze = {{1, 1, 1, 1}, {0, 1, 0, 1}, {0, 1, 0, 1}, {0, 1, 1, 1}};
+        List<String> paths = RatInAMaze.findPaths(maze);
+        assertTrue(paths.size() >= 1);
+        for (String path : paths) {
+            assertTrue(path.chars().allMatch(c -> "DLRU".indexOf(c) >= 0), "Path contains invalid characters: " + path);
+        }
+    }
+}

From 0811cd05e174dec23e05429d280d127f77d92dd0 Mon Sep 17 00:00:00 2001
From: Antariksh Mankar <antariksh.mankar43@gmail.com>
Date: Fri, 15 May 2026 14:30:41 +0530
Subject: [PATCH 1255/1338] [ENHANCEMENT] Add Wavelet Tree Data Structure
 (#7414)

* Implement Wavelet Tree with rank and kthSmallest methods

* Implement Wavelet Tree with rank and kthSmallest methods

* Fix checkstyle multiple variable declarations violation

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../datastructures/trees/WaveletTree.java     | 235 ++++++++++++++++++
 .../datastructures/trees/WaveletTreeTest.java | 117 +++++++++
 2 files changed, 352 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/trees/WaveletTree.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/WaveletTreeTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/WaveletTree.java b/src/main/java/com/thealgorithms/datastructures/trees/WaveletTree.java
new file mode 100644
index 000000000000..6feaa6f35048
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/trees/WaveletTree.java
@@ -0,0 +1,235 @@
+package com.thealgorithms.datastructures.trees;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A Wavelet Tree is a highly efficient data structure used to store sequences
+ * and answer queries like rank, select, and quantile in O(log(max_val - min_val)) time.
+ * This structure is particularly useful in competitive programming and text compression.
+ */
+public class WaveletTree {
+
+    private class Node {
+        int low;
+        int high;
+        Node left;
+        Node right;
+        List<Integer> leftCount; // Prefix sums of elements going to the left child
+
+        /**
+         * Recursively constructs the tree nodes by partitioning the array.
+         *
+         * @param arr  the subarray for the current node
+         * @param low  the minimum possible value in the current node
+         * @param high the maximum possible value in the current node
+         */
+        Node(int[] arr, int low, int high) {
+            this.low = low;
+            this.high = high;
+
+            if (low == high) {
+                return;
+            }
+
+            int mid = low + (high - low) / 2;
+            leftCount = new ArrayList<>(arr.length + 1);
+            leftCount.add(0);
+
+            List<Integer> leftArr = new ArrayList<>();
+            List<Integer> rightArr = new ArrayList<>();
+
+            for (int x : arr) {
+                if (x <= mid) {
+                    leftArr.add(x);
+                    leftCount.add(leftCount.get(leftCount.size() - 1) + 1);
+                } else {
+                    rightArr.add(x);
+                    leftCount.add(leftCount.get(leftCount.size() - 1));
+                }
+            }
+
+            if (!leftArr.isEmpty()) {
+                this.left = new Node(leftArr.stream().mapToInt(i -> i).toArray(), low, mid);
+            }
+            if (!rightArr.isEmpty()) {
+                this.right = new Node(rightArr.stream().mapToInt(i -> i).toArray(), mid + 1, high);
+            }
+        }
+    }
+
+    private Node root;
+    private final int n;
+
+    /**
+     * Constructs a Wavelet Tree from the given array.
+     * The min and max values are determined dynamically from the array.
+     *
+     * @param arr the input array
+     */
+    public WaveletTree(int[] arr) {
+        if (arr == null || arr.length == 0) {
+            this.n = 0;
+            return;
+        }
+        this.n = arr.length;
+        int min = arr[0];
+        int max = arr[0];
+        for (int x : arr) {
+            if (x < min) {
+                min = x;
+            }
+            if (x > max) {
+                max = x;
+            }
+        }
+        root = new Node(arr, min, max);
+    }
+
+    /**
+     * Constructs a Wavelet Tree from the given array with specific min and max values.
+     *
+     * @param arr      the input array
+     * @param minValue the minimum possible value
+     * @param maxValue the maximum possible value
+     */
+    public WaveletTree(int[] arr, int minValue, int maxValue) {
+        if (arr == null || arr.length == 0) {
+            this.n = 0;
+            return;
+        }
+        this.n = arr.length;
+        root = new Node(arr, minValue, maxValue);
+    }
+
+    /**
+     * How many times does the number x appear in the array from index 0 to i (inclusive)?
+     *
+     * @param x the number to search for
+     * @param i the end index (0-based, inclusive)
+     * @return the number of occurrences of x in arr[0...i]
+     */
+    public int rank(int x, int i) {
+        if (root == null || x < root.low || x > root.high || i < 0) {
+            return 0;
+        }
+        // If i is out of bounds, cap it at n - 1
+        int endIdx = Math.min(i, n - 1);
+        return rank(root, x, endIdx + 1);
+    }
+
+    private int rank(Node node, int x, int count) {
+        if (node == null || count == 0) {
+            return 0;
+        }
+        if (node.low == node.high) {
+            return count;
+        }
+        int mid = node.low + (node.high - node.low) / 2;
+        int leftC = node.leftCount.get(count);
+        if (x <= mid) {
+            return rank(node.left, x, leftC);
+        } else {
+            return rank(node.right, x, count - leftC);
+        }
+    }
+
+    /**
+     * What is the 0-based index of the k-th occurrence of the number x in the array?
+     *
+     * @param x the number to search for
+     * @param k the occurrence count (1-based)
+     * @return the 0-based index in the original array, or -1 if x occurs less than k times
+     */
+    public int select(int x, int k) {
+        if (root == null || x < root.low || x > root.high || k <= 0) {
+            return -1;
+        }
+        if (rank(x, n - 1) < k) {
+            return -1;
+        }
+        return select(root, x, k);
+    }
+
+    private int select(Node node, int x, int k) {
+        if (node.low == node.high) {
+            return k - 1; // 0-based index within the imaginary array at the leaf
+        }
+        int mid = node.low + (node.high - node.low) / 2;
+        if (x <= mid) {
+            int posInLeft = select(node.left, x, k);
+            return binarySearchLeft(node.leftCount, posInLeft + 1);
+        } else {
+            int posInRight = select(node.right, x, k);
+            return binarySearchRight(node.leftCount, posInRight + 1);
+        }
+    }
+
+    private int binarySearchLeft(List<Integer> prefixSums, int k) {
+        int l = 1;
+        int r = prefixSums.size() - 1;
+        int ans = -1;
+        while (l <= r) {
+            int mid = l + (r - l) / 2;
+            if (prefixSums.get(mid) >= k) {
+                ans = mid;
+                r = mid - 1;
+            } else {
+                l = mid + 1;
+            }
+        }
+        return ans == -1 ? -1 : ans - 1; // Convert to 0-based index
+    }
+
+    private int binarySearchRight(List<Integer> prefixSums, int k) {
+        int l = 1;
+        int r = prefixSums.size() - 1;
+        int ans = -1;
+        while (l <= r) {
+            int mid = l + (r - l) / 2;
+            if (mid - prefixSums.get(mid) >= k) {
+                ans = mid;
+                r = mid - 1;
+            } else {
+                l = mid + 1;
+            }
+        }
+        return ans == -1 ? -1 : ans - 1; // Convert to 0-based index
+    }
+
+    /**
+     * If you sort the subarray from index left to right, what would be the k-th smallest element?
+     * This query is also commonly known as the quantile query.
+     *
+     * @param left  the start index of the subarray (0-based, inclusive)
+     * @param right the end index of the subarray (0-based, inclusive)
+     * @param k     the rank of the smallest element (1-based, e.g., k=1 is the minimum)
+     * @return the k-th smallest element in the subarray, or -1 if invalid parameters
+     */
+    public int kthSmallest(int left, int right, int k) {
+        if (root == null || left > right || left < 0 || k < 1 || k > right - left + 1) {
+            return -1;
+        }
+        return kthSmallest(root, left, right, k);
+    }
+
+    private int kthSmallest(Node node, int left, int right, int k) {
+        if (node.low == node.high) {
+            return node.low;
+        }
+
+        int countLeftInLMinus1 = (left == 0) ? 0 : node.leftCount.get(left);
+        int countLeftInR = node.leftCount.get(right + 1);
+        int elementsToLeft = countLeftInR - countLeftInLMinus1;
+
+        if (k <= elementsToLeft) {
+            int newL = countLeftInLMinus1;
+            int newR = countLeftInR - 1;
+            return kthSmallest(node.left, newL, newR, k);
+        } else {
+            int newL = left - countLeftInLMinus1;
+            int newR = right - countLeftInR;
+            return kthSmallest(node.right, newL, newR, k - elementsToLeft);
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/WaveletTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/WaveletTreeTest.java
new file mode 100644
index 000000000000..592170673a3a
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/WaveletTreeTest.java
@@ -0,0 +1,117 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class WaveletTreeTest {
+
+    @Test
+    public void testRank() {
+        int[] arr = {5, 1, 2, 5, 1};
+        WaveletTree wt = new WaveletTree(arr);
+
+        // x = 1
+        assertEquals(1, wt.rank(1, 1)); // In [5, 1], '1' appears 1 time
+        assertEquals(2, wt.rank(1, 4)); // In [5, 1, 2, 5, 1], '1' appears 2 times
+        assertEquals(0, wt.rank(1, 0)); // In [5], '1' appears 0 times
+
+        // x = 5
+        assertEquals(1, wt.rank(5, 0)); // In [5], '5' appears 1 time
+        assertEquals(1, wt.rank(5, 2)); // In [5, 1, 2], '5' appears 1 time
+        assertEquals(2, wt.rank(5, 4)); // In [5, 1, 2, 5, 1], '5' appears 2 times
+
+        // Out of bounds / invalid value
+        assertEquals(0, wt.rank(10, 4)); // '10' is not in the array
+        assertEquals(0, wt.rank(5, -1)); // Invalid end index
+    }
+
+    @Test
+    public void testSelect() {
+        int[] arr = {5, 1, 2, 5, 1};
+        WaveletTree wt = new WaveletTree(arr);
+
+        assertEquals(1, wt.select(1, 1)); // 1st '1' is at index 1
+        assertEquals(4, wt.select(1, 2)); // 2nd '1' is at index 4
+
+        assertEquals(0, wt.select(5, 1)); // 1st '5' is at index 0
+        assertEquals(3, wt.select(5, 2)); // 2nd '5' is at index 3
+
+        assertEquals(2, wt.select(2, 1)); // 1st '2' is at index 2
+
+        assertEquals(-1, wt.select(5, 3)); // 3rd '5' doesn't exist
+        assertEquals(-1, wt.select(10, 1)); // '10' doesn't exist
+        assertEquals(-1, wt.select(5, 0)); // invalid k
+    }
+
+    @Test
+    public void testKthSmallest() {
+        int[] arr = {5, 1, 2, 5, 1};
+        WaveletTree wt = new WaveletTree(arr);
+
+        // Array: [5, 1, 2, 5, 1] -> Sorted: [1, 1, 2, 5, 5]
+        assertEquals(1, wt.kthSmallest(0, 4, 1)); // 1st smallest in [5, 1, 2, 5, 1] is 1
+        assertEquals(1, wt.kthSmallest(0, 4, 2)); // 2nd smallest in [5, 1, 2, 5, 1] is 1
+        assertEquals(2, wt.kthSmallest(0, 4, 3)); // 3rd smallest in [5, 1, 2, 5, 1] is 2
+        assertEquals(5, wt.kthSmallest(0, 4, 4)); // 4th smallest in [5, 1, 2, 5, 1] is 5
+        assertEquals(5, wt.kthSmallest(0, 4, 5)); // 5th smallest in [5, 1, 2, 5, 1] is 5
+
+        // Subarray: arr[1..3] = [1, 2, 5] -> Sorted: [1, 2, 5]
+        assertEquals(1, wt.kthSmallest(1, 3, 1)); // 1st smallest in [1, 2, 5] is 1
+        assertEquals(2, wt.kthSmallest(1, 3, 2)); // 2nd smallest in [1, 2, 5] is 2
+        assertEquals(5, wt.kthSmallest(1, 3, 3)); // 3rd smallest in [1, 2, 5] is 5
+
+        // Invalid ranges / arguments
+        assertEquals(-1, wt.kthSmallest(4, 2, 1)); // Invalid range (left > right)
+        assertEquals(-1, wt.kthSmallest(0, 4, 10)); // k > range length
+        assertEquals(-1, wt.kthSmallest(0, 4, 0)); // k < 1
+    }
+
+    @Test
+    public void testEmptyAndSingleElementArray() {
+        WaveletTree wtEmpty = new WaveletTree(new int[] {});
+        assertEquals(0, wtEmpty.rank(1, 0));
+        assertEquals(-1, wtEmpty.select(1, 1));
+        assertEquals(-1, wtEmpty.kthSmallest(0, 0, 1));
+
+        WaveletTree wtSingle = new WaveletTree(new int[] {42});
+        assertEquals(1, wtSingle.rank(42, 0));
+        assertEquals(0, wtSingle.rank(42, -1));
+        assertEquals(0, wtSingle.select(42, 1));
+        assertEquals(-1, wtSingle.select(42, 2));
+        assertEquals(42, wtSingle.kthSmallest(0, 0, 1));
+    }
+
+    @Test
+    public void testNullArrayAndCustomBounds() {
+        WaveletTree wtNull = new WaveletTree(null);
+        assertEquals(0, wtNull.rank(1, 0));
+
+        WaveletTree wtNullCustom = new WaveletTree(null, 1, 5);
+        assertEquals(-1, wtNullCustom.select(1, 1));
+
+        int[] arr = {5, 1, 2, 5, 1};
+        WaveletTree wtCustom = new WaveletTree(arr, 1, 10);
+        assertEquals(2, wtCustom.rank(5, 4));
+        assertEquals(0, wtCustom.rank(4, 4)); // Query an element inside bounds but not in array
+        assertEquals(0, wtCustom.rank(10, 4)); // Query upper bound
+    }
+
+    @Test
+    public void testNegativeValues() {
+        int[] arr = {-5, 10, -2, 0, -5};
+        WaveletTree wt = new WaveletTree(arr);
+
+        assertEquals(2, wt.rank(-5, 4));
+        assertEquals(1, wt.rank(0, 3));
+
+        assertEquals(0, wt.select(-5, 1));
+        assertEquals(4, wt.select(-5, 2));
+        assertEquals(3, wt.select(0, 1));
+
+        // Sorted: [-5, -5, -2, 0, 10]
+        assertEquals(-5, wt.kthSmallest(0, 4, 1));
+        assertEquals(-2, wt.kthSmallest(0, 4, 3));
+        assertEquals(10, wt.kthSmallest(0, 4, 5));
+    }
+}

From 783c96f949095e2a9723724e9e301ac983ddab5d Mon Sep 17 00:00:00 2001
From: Utsav Tripathi <tripathiutsav87@gmail.com>
Date: Sun, 17 May 2026 02:30:17 +0530
Subject: [PATCH 1256/1338] Fix: remove floating Javadoc comments causing
 compilation error (#7423)

---
 .../conversions/AnyBaseToAnyBase.java              |  8 +-------
 .../searches/InterpolationSearch.java              | 12 +-----------
 .../com/thealgorithms/searches/LinearSearch.java   | 14 +-------------
 3 files changed, 3 insertions(+), 31 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
index 3d31cb3e7f6c..314e7fba38a3 100644
--- a/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
+++ b/src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java
@@ -1,10 +1,4 @@
-/**
- * [Brief description of what the algorithm does]
- * <p>
- * Time Complexity: O(n) [or appropriate complexity]
- * Space Complexity: O(n)
- * @author Reshma Kakkirala
- */
+
 package com.thealgorithms.conversions;
 
 import java.util.Arrays;
diff --git a/src/main/java/com/thealgorithms/searches/InterpolationSearch.java b/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
index d24cc1c774bc..272627fc48b4 100644
--- a/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
+++ b/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
@@ -1,14 +1,4 @@
-/**
- * Interpolation Search estimates the position of the target value
- * based on the distribution of values.
- *
- * Example:
- * Input: [10, 20, 30, 40], target = 30
- * Output: Index = 2
- *
- * Time Complexity: O(log log n) (average case)
- * Space Complexity: O(1)
- */
+
 package com.thealgorithms.searches;
 
 /**
diff --git a/src/main/java/com/thealgorithms/searches/LinearSearch.java b/src/main/java/com/thealgorithms/searches/LinearSearch.java
index 3f273e167f0a..bd14fe21ea03 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearch.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearch.java
@@ -1,16 +1,4 @@
-/**
- * Performs Linear Search on an array.
- *
- * Linear search checks each element one by one until the target is found
- * or the array ends.
- *
- * Example:
- * Input: [2, 4, 6, 8], target = 6
- * Output: Index = 2
- *
- * Time Complexity: O(n)
- * Space Complexity: O(1)
- */
+
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;

From 8848ed1eab41bf5d272e7fc7e9d90b5350157d7e Mon Sep 17 00:00:00 2001
From: Utsav Tripathi <tripathiutsav87@gmail.com>
Date: Sun, 17 May 2026 16:35:57 +0530
Subject: [PATCH 1257/1338] Docs: add Javadoc to CoinChange class and method
 (#7424)

* Fix: remove floating Javadoc comments causing compilation error

* Docs: add Javadoc to CoinChange class and method

* Style: apply clang-format to CoinChange.java
---
 .../greedyalgorithms/CoinChange.java          | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java b/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
index 8054581d21d7..5f9f6080d0e1 100644
--- a/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
+++ b/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java
@@ -6,10 +6,30 @@
 
 // Problem Link : https://en.wikipedia.org/wiki/Change-making_problem
 
+/**
+ * The Coin Change problem finds the minimum number of coins needed
+ * to make a given amount using a greedy approach.
+ *
+ * <p>Note: This greedy approach works optimally for standard coin systems
+ * (like Indian currency), but may not work for all arbitrary coin sets.
+ * For arbitrary denominations, dynamic programming is preferred.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Change-making_problem">Change-making problem</a>
+ */
 public final class CoinChange {
     private CoinChange() {
     }
-    // Function to solve the coin change problem
+
+    /**
+     * Returns the list of coins used to make the given amount
+     * using a greedy algorithm with standard denominations.
+     *
+     * <p>Time Complexity: O(n log n) where n is the number of coin denominations
+     * <p>Space Complexity: O(n)
+     *
+     * @param amount the total amount to make change for
+     * @return list of coins used to make the amount
+     */
     public static ArrayList<Integer> coinChangeProblem(int amount) {
         // Define an array of coin denominations in descending order
         Integer[] coins = {1, 2, 5, 10, 20, 50, 100, 500, 2000};

From 4b8099c27b4f7fe7dc465d80ed0a5d9e78bd4153 Mon Sep 17 00:00:00 2001
From: Shubham Bhati <112773220+Shubh2-0@users.noreply.github.com>
Date: Mon, 18 May 2026 13:07:32 +0530
Subject: [PATCH 1258/1338] fix: add null input validation to
 AlternativeStringArrange.arrange() (#7425)

* fix: add null input validation to AlternativeStringArrange.arrange()

The arrange() method previously threw a NullPointerException when either
input string was null. This change explicitly validates the inputs and
throws IllegalArgumentException with a clear message, matching the
fail-fast pattern used by other utility classes in this package (e.g.
HammingDistance).

- Add null guard at the start of arrange()
- Update Javadoc with @throws and contract notes
- Add parameterized test covering all three null-input combinations

* fix: remove unused JUnit @Test import (Checkstyle violation)
---
 .../strings/AlternativeStringArrange.java           | 11 +++++++++--
 .../strings/AlternativeStringArrangeTest.java       | 13 +++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/strings/AlternativeStringArrange.java b/src/main/java/com/thealgorithms/strings/AlternativeStringArrange.java
index cf736dbd8cab..016ee2821a17 100644
--- a/src/main/java/com/thealgorithms/strings/AlternativeStringArrange.java
+++ b/src/main/java/com/thealgorithms/strings/AlternativeStringArrange.java
@@ -21,12 +21,19 @@ private AlternativeStringArrange() {
 
     /**
      * Arranges two strings by alternating their characters.
+     * If one string is longer than the other, the remaining characters of the longer string
+     * are appended at the end of the result.
      *
-     * @param firstString  the first input string
-     * @param secondString the second input string
+     * @param firstString  the first input string, must not be {@code null}
+     * @param secondString the second input string, must not be {@code null}
      * @return a new string with characters from both strings arranged alternately
+     * @throws IllegalArgumentException if {@code firstString} or {@code secondString} is {@code null}
      */
     public static String arrange(String firstString, String secondString) {
+        if (firstString == null || secondString == null) {
+            throw new IllegalArgumentException("Input strings must not be null");
+        }
+
         StringBuilder result = new StringBuilder();
         int length1 = firstString.length();
         int length2 = secondString.length();
diff --git a/src/test/java/com/thealgorithms/strings/AlternativeStringArrangeTest.java b/src/test/java/com/thealgorithms/strings/AlternativeStringArrangeTest.java
index 9e8ae9e9f153..4cd55a4d7410 100644
--- a/src/test/java/com/thealgorithms/strings/AlternativeStringArrangeTest.java
+++ b/src/test/java/com/thealgorithms/strings/AlternativeStringArrangeTest.java
@@ -1,9 +1,11 @@
 package com.thealgorithms.strings;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.stream.Stream;
 import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
 class AlternativeStringArrangeTest {
@@ -20,4 +22,15 @@ private static Stream<Object[]> provideTestData() {
     void arrangeTest(String input1, String input2, String expected) {
         assertEquals(expected, AlternativeStringArrange.arrange(input1, input2));
     }
+
+    @ParameterizedTest(name = "null input ({0}, {1}) should throw IllegalArgumentException")
+    @MethodSource("provideNullInputs")
+    void arrangeThrowsOnNullInput(String input1, String input2) {
+        IllegalArgumentException ex = assertThrows(IllegalArgumentException.class, () -> AlternativeStringArrange.arrange(input1, input2));
+        assertEquals("Input strings must not be null", ex.getMessage());
+    }
+
+    private static Stream<Arguments> provideNullInputs() {
+        return Stream.of(Arguments.of(null, "abc"), Arguments.of("abc", null), Arguments.of(null, null));
+    }
 }

From 3ee310ec80fe0bfbc27ef97841471e5085326b69 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 21 May 2026 21:09:26 +0200
Subject: [PATCH 1259/1338] chore(deps): bump org.junit:junit-bom from 6.0.3 to
 6.1.0 (#7431)

* chore(deps): bump org.junit:junit-bom from 6.0.3 to 6.1.0

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 6.0.3 to 6.1.0.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r6.0.3...r6.1.0)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 6.1.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* style: resolve `DLS_DEAD_LOCAL_STORE` in `testIteratorEmptyBag`

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 pom.xml                                                     | 2 +-
 .../java/com/thealgorithms/datastructures/bag/BagTest.java  | 6 ++----
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/pom.xml b/pom.xml
index e0a3486b23bb..3fb0887973e0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>6.0.3</version>
+                <version>6.1.0</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
diff --git a/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java b/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
index 8212793dfb79..f85a4628a1ac 100644
--- a/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/bag/BagTest.java
@@ -98,11 +98,9 @@ void testIterator() {
     @Test
     void testIteratorEmptyBag() {
         Bag<String> bag = new Bag<>();
-        int count = 0;
-        for (String ignored : bag) {
-            org.junit.jupiter.api.Assertions.fail("Iterator should not return any items for an empty bag");
+        for (String item : bag) {
+            org.junit.jupiter.api.Assertions.fail("Iterator returned item for an empty bag:" + item);
         }
-        assertEquals(0, count, "Iterator should not traverse any items in an empty bag");
     }
 
     @Test

From 0a62b113d64f6641ae25896c60da142fbc5c8cf8 Mon Sep 17 00:00:00 2001
From: premm <sonusharma4237@gmail.com>
Date: Fri, 22 May 2026 03:14:21 +0530
Subject: [PATCH 1260/1338] feat: add optimized Digit DP template and unit
 tests (#7430)

* feat: add optimized Digit DP template and unit tests

* test: add test cases for max target sum and memoization hit to achieve 100% coverage

* style: fix indentation and code formatting for clang linter compliance

* fix: remove checkstyle inner assignment in solve method

* fix: remove checkstyle inner assignment in solve method -newline at end
---
 .../dynamicprogramming/DigitDP.java           | 111 ++++++++++++++++++
 .../dynamicprogramming/DigitDPTest.java       |  70 +++++++++++
 2 files changed, 181 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/dynamicprogramming/DigitDP.java
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/DigitDPTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/DigitDP.java b/src/main/java/com/thealgorithms/dynamicprogramming/DigitDP.java
new file mode 100644
index 000000000000..7dae7603fedc
--- /dev/null
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/DigitDP.java
@@ -0,0 +1,111 @@
+package com.thealgorithms.dynamicprogramming;
+import java.util.Arrays;
+
+/**
+ * A generalized template for the Digit Dynamic Programming (Digit DP)
+ * technique.
+ * Digit DP is used to count numbers within a range [L, R] that satisfy specific
+ * digit properties.
+ * This specific implementation demonstrates counting the numbers whose digit
+ * sum equals a target value.
+ *
+ * <p>
+ * Example:
+ * countRangeWithDigitSum(1, 100, 5) returns 6 (numbers: 5, 14, 23, 32, 41, 50)
+ */
+public final class DigitDP {
+
+    // Maximum theoretical digit sum for a 64-bit signed long integer (9 * 19 digits
+    // = 171)
+    private static final int MAX_DIGIT_SUM = 171;
+
+    private DigitDP() {
+        // Prevent instantiation for utility/algorithm template class
+    }
+
+    /**
+     * Counts how many numbers in the range [L, R] have a digit sum equal to the
+     * target.
+     *
+     * @param l      The lower bound of the range (inclusive).
+     * @param r      The upper bound of the range (inclusive).
+     * @param target The exact sum of digits required.
+     * @return The count of valid integers.
+     */
+    public static long countRangeWithDigitSum(long l, long r, int target) {
+        if (l > r || target < 0 || target > MAX_DIGIT_SUM) {
+            return 0;
+        }
+        long countR = countWithDigitSum(r, target);
+        long countLMinus1 = countWithDigitSum(l - 1, target);
+        return countR - countLMinus1;
+    }
+
+    private static long countWithDigitSum(long number, int target) {
+        if (number < 0) {
+            return 0;
+        }
+        String numStr = Long.toString(number);
+        int length = numStr.length();
+
+        // dp[index][current_sum][tight]
+        long[][][] dp = new long[length][MAX_DIGIT_SUM + 1][2];
+        for (long[][] row : dp) {
+            for (long[] col : row) {
+                Arrays.fill(col, -1);
+            }
+        }
+
+        return solve(0, 0, 1, numStr, target, dp);
+    }
+
+    /**
+     * Recursive memoized function to explore digit placements.
+     *
+     * Time Complexity: O(number_of_digits * target_sum * 10)
+     * Space Complexity: O(number_of_digits * target_sum * 2)
+     *
+     * @param index      Current digit position from left to right (most significant
+     *                   first).
+     * @param currentSum Cumulative sum of digits chosen so far.
+     * @param tight      Flag indicating if current prefix matches the original
+     *                   number boundary.
+     * @param numStr     String representation of the upper ceiling limit.
+     * @param target     The exact required sum of digits.
+     * @param dp         Memoization matrix cache table.
+     * @return Total valid combinations from the current state configuration.
+     */
+    private static long solve(int index, int currentSum, int tight, String numStr, int target, long[][][] dp) {
+        // Base case: If we have processed all digits
+        if (index == numStr.length()) {
+            return currentSum == target ? 1 : 0;
+        }
+
+        // Return memoized state if already evaluated
+        if (dp[index][currentSum][tight] != -1) {
+            return dp[index][currentSum][tight];
+        }
+
+        long ans = 0;
+        // Determine the maximum limit for the current position digit
+        int limit = (tight == 1) ? (numStr.charAt(index) - '0') : 9;
+
+        // Iterate through all possible valid digits for this position
+        for (int digit = 0; digit <= limit; digit++) {
+            int nextSum = currentSum + digit;
+
+            // Optimization: If the digit sum exceeds the target, prune branch
+            if (nextSum > target) {
+                continue;
+            }
+
+            // Next state remains tight only if current state is tight and we place the
+            // exact limit digit
+            int nextTight = (tight == 1 && digit == limit) ? 1 : 0;
+            ans += solve(index + 1, nextSum, nextTight, numStr, target, dp);
+        }
+
+        dp[index][currentSum][tight] = ans;
+        return ans;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/DigitDPTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/DigitDPTest.java
new file mode 100644
index 000000000000..762fe86d4d65
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/DigitDPTest.java
@@ -0,0 +1,70 @@
+package com.thealgorithms.dynamicprogramming;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the generalized DigitDP implementation.
+ */
+public class DigitDPTest {
+
+    @Test
+    public void testDigitDPBasicRange() {
+        // Numbers between 1 and 20 with a digit sum of 5: 5, 14
+        long result = DigitDP.countRangeWithDigitSum(1, 20, 5);
+        assertEquals(2, result);
+    }
+
+    @Test
+    public void testDigitDPZeroBound() {
+        // Number 0 has a digit sum of 0
+        long result = DigitDP.countRangeWithDigitSum(0, 0, 0);
+        assertEquals(1, result);
+    }
+
+    @Test
+    public void testDigitDPLargeRange() {
+        // Count numbers between 1 and 100 with a digit sum of 9
+        // 9, 18, 27, 36, 45, 54, 63, 72, 81, 90 (10 numbers)
+        long result = DigitDP.countRangeWithDigitSum(1, 100, 9);
+        assertEquals(10, result);
+    }
+
+    @Test
+    public void testDigitDPNoMatches() {
+        // No numbers between 10 and 15 can have a digit sum of 20
+        long result = DigitDP.countRangeWithDigitSum(10, 15, 20);
+        assertEquals(0, result);
+    }
+
+    @Test
+    public void testDigitDPExceedsMaxSum() {
+        // Sum condition that exceeds max possible physical sum array constraints
+        // gracefully returns 0
+        long result = DigitDP.countRangeWithDigitSum(1, 100, 200);
+        assertEquals(0, result);
+    }
+
+    @Test
+    public void testDigitDPInvalidRange() {
+        // Lower bound greater than upper bound should evaluate gracefully to 0
+        long result = DigitDP.countRangeWithDigitSum(50, 20, 5);
+        assertEquals(0, result);
+    }
+
+    @Test
+    public void testDigitDPExceedsMaxSumEdgeCase() {
+        // Yeh test case target > MAX_DIGIT_SUM wali condition ko hit karega
+        long result = DigitDP.countRangeWithDigitSum(1, 100, 180);
+        assertEquals(0, result);
+    }
+
+    @Test
+    public void testDigitDPMemoizationHit() {
+        // Badi range dene se overlapping subproblems bante hain,
+        // jisse memoization hit hogi aur coverage 100% ho jayegi.
+        long result1 = DigitDP.countRangeWithDigitSum(1, 100000, 15);
+        long result2 = DigitDP.countRangeWithDigitSum(1, 100000, 15);
+        assertEquals(result1, result2);
+    }
+}

From e49cd55255711fa2ce3f4d99faae026318813484 Mon Sep 17 00:00:00 2001
From: Md Mushfiqur Rahim <20mahin2020@gmail.com>
Date: Tue, 26 May 2026 01:49:36 +0600
Subject: [PATCH 1261/1338] feat(datastructures): add thread-safe bounded queue
 implementation (#7428)

* feat(datastructures): add thread-safe bounded queue implementation

Implements a thread-safe blocking queue using ReentrantLock and
Condition variables for producer-consumer synchronization.

### What This Adds

**ThreadSafeQueue.java** - Thread-safe bounded queue:
- `enqueue()` - Blocking add to tail, waits when queue is full
- `dequeue()` - Blocking remove from head, waits when queue is empty
- `offer()` - Non-blocking add, returns false when full
- `poll()` - Non-blocking remove, returns null when empty
- `size()`, `isEmpty()`, `isFull()`, `capacity()` - State queries
- Uses circular buffer for O(1) enqueue/dequeue operations
- Supports multiple concurrent producers and consumers

**ThreadSafeQueueTest.java** - Comprehensive test suite:
- Basic enqueue/dequeue operations
- Offer/poll non-blocking behavior
- Null rejection validation
- Invalid capacity rejection
- Circular buffer wrap-around
- Multiple producers single consumer concurrency
- Single producer multiple consumers concurrency
- Blocking behavior verification
- Stress test with 8 concurrent threads

### Algorithm

Uses a circular buffer with ReentrantLock and two Condition variables:
- `notFull` - signaled when space becomes available
- `notEmpty` - signaled when items are added
- Producers await notFull when buffer is full
- Consumers await notEmpty when buffer is empty
- Signal opposite condition after each operation

Time: O(1) enqueue/dequeue | Space: O(n) bounded buffer

### Reference

https://en.wikipedia.org/wiki/Producer%E2%80%93consumer_problem

* fix(datastructures): correct test capacity and simplify concurrent test

- testOfferPoll: Changed capacity from 3 to 2 so third offer correctly fails
- testMultipleProducersSingleConsumer: Removed startLatch, use dedicated
  consumer thread with synchronized results list for thread safety

* fix(datastructures): remove unused assertArrayEquals import

Checkstyle flagged UnusedImports violation for
org.junit.jupiter.api.Assertions.assertArrayEquals which was
not used in any test method.

* fix: replace signal() with signalAll() to satisfy SpotBugs MDM_SIGNAL_NOT_SIGNALALL

SpotBugs flags all four Condition.signal() calls in ThreadSafeQueue as Medium
severity bugs (MDM_SIGNAL_NOT_SIGNALALL). In a multi-producer/multi-consumer
scenario, signal() wakes only one waiting thread, which can cause deadlock when
multiple producers or consumers are blocked on the same condition variable.
Using signalAll() ensures all waiting threads are notified and can re-check
their loop condition, preventing the lost-wakeup problem that occurs when a
single signal wakes a thread that cannot make progress.

This change affects enqueue(), dequeue(), offer(), and poll() methods where
notEmpty.signal() and notFull.signal() are replaced with notEmpty.signalAll()
and notFull.signalAll() respectively.

* test: replace static imports with Assertions prefix to satisfy PMD TooManyStaticImports

PMD flags TooManyStaticImports when more than 4 static imports are present.
The test file had 5 static imports from org.junit.jupiter.api.Assertions
(equals, assertFalse, assertNull, assertThrows, assertTrue) which exceeded
the default threshold. Replaced with regular import and Assertions.
prefix to eliminate the PMD violation while maintaining readability.
---
 .../queues/ThreadSafeQueue.java               | 186 +++++++++++
 .../queues/ThreadSafeQueueTest.java           | 295 ++++++++++++++++++
 2 files changed, 481 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/queues/ThreadSafeQueue.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/queues/ThreadSafeQueueTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/queues/ThreadSafeQueue.java b/src/main/java/com/thealgorithms/datastructures/queues/ThreadSafeQueue.java
new file mode 100644
index 000000000000..a943b0028974
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/queues/ThreadSafeQueue.java
@@ -0,0 +1,186 @@
+package com.thealgorithms.datastructures.queues;
+
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * @brief Thread-safe bounded queue implementation using ReentrantLock and Condition variables
+ * @details A blocking queue that supports multiple producers and consumers.
+ * Uses a circular buffer internally with lock-based synchronization to ensure
+ * thread safety. Producers block when the queue is full, and consumers block
+ * when the queue is empty.
+ * @see <a href="https://en.wikipedia.org/wiki/Producer%E2%80%93consumer_problem">Producer-Consumer Problem</a>
+ */
+public class ThreadSafeQueue<T> {
+
+    private final Object[] buffer;
+    private final int capacity;
+    private int head;
+    private int tail;
+    private int count;
+    private final ReentrantLock lock;
+    private final Condition notFull;
+    private final Condition notEmpty;
+
+    /**
+     * @brief Constructs a ThreadSafeQueue with the specified capacity
+     * @param capacity the maximum number of elements the queue can hold
+     * @throws IllegalArgumentException if capacity is less than or equal to zero
+     */
+    public ThreadSafeQueue(int capacity) {
+        if (capacity <= 0) {
+            throw new IllegalArgumentException("Capacity must be greater than zero.");
+        }
+        this.capacity = capacity;
+        this.buffer = new Object[capacity];
+        this.head = 0;
+        this.tail = 0;
+        this.count = 0;
+        this.lock = new ReentrantLock();
+        this.notFull = lock.newCondition();
+        this.notEmpty = lock.newCondition();
+    }
+
+    /**
+     * @brief Adds an element to the tail of the queue, blocking if full
+     * @param item the element to add
+     * @throws InterruptedException if the thread is interrupted while waiting
+     * @throws IllegalArgumentException if the item is null
+     */
+    public void enqueue(T item) throws InterruptedException {
+        if (item == null) {
+            throw new IllegalArgumentException("Cannot enqueue null item.");
+        }
+
+        lock.lock();
+        try {
+            while (count == capacity) {
+                notFull.await();
+            }
+            buffer[tail] = item;
+            tail = (tail + 1) % capacity;
+            count++;
+            notEmpty.signalAll();
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * @brief Removes and returns the element at the head of the queue, blocking if empty
+     * @return the element at the head of the queue
+     * @throws InterruptedException if the thread is interrupted while waiting
+     */
+    @SuppressWarnings("unchecked")
+    public T dequeue() throws InterruptedException {
+        lock.lock();
+        try {
+            while (count == 0) {
+                notEmpty.await();
+            }
+            T item = (T) buffer[head];
+            buffer[head] = null;
+            head = (head + 1) % capacity;
+            count--;
+            notFull.signalAll();
+            return item;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * @brief Adds an element to the tail of the queue without blocking
+     * @param item the element to add
+     * @return true if the element was added, false if the queue was full
+     * @throws IllegalArgumentException if the item is null
+     */
+    public boolean offer(T item) {
+        if (item == null) {
+            throw new IllegalArgumentException("Cannot enqueue null item.");
+        }
+
+        lock.lock();
+        try {
+            if (count == capacity) {
+                return false;
+            }
+            buffer[tail] = item;
+            tail = (tail + 1) % capacity;
+            count++;
+            notEmpty.signalAll();
+            return true;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * @brief Removes and returns the element at the head without blocking
+     * @return the element at the head, or null if the queue is empty
+     */
+    @SuppressWarnings("unchecked")
+    public T poll() {
+        lock.lock();
+        try {
+            if (count == 0) {
+                return null;
+            }
+            T item = (T) buffer[head];
+            buffer[head] = null;
+            head = (head + 1) % capacity;
+            count--;
+            notFull.signalAll();
+            return item;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * @brief Returns the number of elements in the queue
+     * @return the current size of the queue
+     */
+    public int size() {
+        lock.lock();
+        try {
+            return count;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * @brief Checks if the queue is empty
+     * @return true if the queue contains no elements
+     */
+    public boolean isEmpty() {
+        lock.lock();
+        try {
+            return count == 0;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * @brief Checks if the queue is full
+     * @return true if the queue has reached its capacity
+     */
+    public boolean isFull() {
+        lock.lock();
+        try {
+            return count == capacity;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * @brief Returns the maximum capacity of the queue
+     * @return the capacity
+     */
+    public int capacity() {
+        return capacity;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/queues/ThreadSafeQueueTest.java b/src/test/java/com/thealgorithms/datastructures/queues/ThreadSafeQueueTest.java
new file mode 100644
index 000000000000..4c038c05b167
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/queues/ThreadSafeQueueTest.java
@@ -0,0 +1,295 @@
+package com.thealgorithms.datastructures.queues;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class ThreadSafeQueueTest {
+
+    @Test
+    public void testEnqueueDequeue() throws InterruptedException {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(5);
+        queue.enqueue(1);
+        queue.enqueue(2);
+        queue.enqueue(3);
+
+        Assertions.assertEquals(3, queue.size());
+        Assertions.assertEquals(1, queue.dequeue());
+        Assertions.assertEquals(2, queue.dequeue());
+        Assertions.assertEquals(3, queue.dequeue());
+        Assertions.assertTrue(queue.isEmpty());
+    }
+
+    @Test
+    public void testOfferPoll() {
+        ThreadSafeQueue<String> queue = new ThreadSafeQueue<>(2);
+        Assertions.assertTrue(queue.offer("a"));
+        Assertions.assertTrue(queue.offer("b"));
+        Assertions.assertFalse(queue.offer("c"));
+
+        Assertions.assertEquals("a", queue.poll());
+        Assertions.assertEquals("b", queue.poll());
+        Assertions.assertNull(queue.poll());
+    }
+
+    @Test
+    public void testOfferRejectsWhenFull() {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(2);
+        Assertions.assertTrue(queue.offer(1));
+        Assertions.assertTrue(queue.offer(2));
+        Assertions.assertFalse(queue.offer(3));
+        Assertions.assertEquals(2, queue.size());
+    }
+
+    @Test
+    public void testPollReturnsNullWhenEmpty() {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(5);
+        Assertions.assertNull(queue.poll());
+    }
+
+    @Test
+    public void testEnqueueNullThrows() {
+        ThreadSafeQueue<String> queue = new ThreadSafeQueue<>(5);
+        Assertions.assertThrows(IllegalArgumentException.class, () -> queue.enqueue(null));
+    }
+
+    @Test
+    public void testOfferNullThrows() {
+        ThreadSafeQueue<String> queue = new ThreadSafeQueue<>(5);
+        Assertions.assertThrows(IllegalArgumentException.class, () -> queue.offer(null));
+    }
+
+    @Test
+    public void testInvalidCapacityThrows() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new ThreadSafeQueue<>(0));
+        Assertions.assertThrows(IllegalArgumentException.class, () -> new ThreadSafeQueue<>(-1));
+    }
+
+    @Test
+    public void testIsEmptyAndIsFull() throws InterruptedException {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(2);
+        Assertions.assertTrue(queue.isEmpty());
+        Assertions.assertFalse(queue.isFull());
+
+        queue.enqueue(1);
+        Assertions.assertFalse(queue.isEmpty());
+        Assertions.assertFalse(queue.isFull());
+
+        queue.enqueue(2);
+        Assertions.assertFalse(queue.isEmpty());
+        Assertions.assertTrue(queue.isFull());
+
+        queue.dequeue();
+        Assertions.assertFalse(queue.isEmpty());
+        Assertions.assertFalse(queue.isFull());
+
+        queue.dequeue();
+        Assertions.assertTrue(queue.isEmpty());
+        Assertions.assertFalse(queue.isFull());
+    }
+
+    @Test
+    public void testCapacity() {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(10);
+        Assertions.assertEquals(10, queue.capacity());
+    }
+
+    @Test
+    public void testCircularBufferWrapAround() throws InterruptedException {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(3);
+        queue.enqueue(1);
+        queue.enqueue(2);
+        queue.enqueue(3);
+
+        Assertions.assertEquals(1, queue.dequeue());
+        Assertions.assertEquals(2, queue.dequeue());
+
+        queue.enqueue(4);
+        queue.enqueue(5);
+
+        Assertions.assertEquals(3, queue.dequeue());
+        Assertions.assertEquals(4, queue.dequeue());
+        Assertions.assertEquals(5, queue.dequeue());
+    }
+
+    @Test
+    public void testMultipleProducersSingleConsumer() throws InterruptedException {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(100);
+        int numProducers = 4;
+        int itemsPerProducer = 250;
+        int totalItems = numProducers * itemsPerProducer;
+        CountDownLatch doneLatch = new CountDownLatch(numProducers);
+        List<Integer> results = new ArrayList<>();
+
+        ExecutorService executor = Executors.newFixedThreadPool(numProducers + 1);
+
+        for (int p = 0; p < numProducers; p++) {
+            final int producerId = p;
+            executor.submit(() -> {
+                try {
+                    for (int i = 0; i < itemsPerProducer; i++) {
+                        queue.enqueue(producerId * itemsPerProducer + i);
+                    }
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                } finally {
+                    doneLatch.countDown();
+                }
+            });
+        }
+
+        Thread consumerThread = new Thread(() -> {
+            try {
+                while (results.size() < totalItems) {
+                    Integer item = queue.poll();
+                    if (item != null) {
+                        synchronized (results) {
+                            results.add(item);
+                        }
+                    }
+                }
+            } catch (Exception e) {
+                Thread.currentThread().interrupt();
+            }
+        });
+        consumerThread.start();
+
+        Assertions.assertTrue(doneLatch.await(10, TimeUnit.SECONDS));
+        consumerThread.join(5000);
+
+        Assertions.assertEquals(totalItems, results.size());
+        executor.shutdown();
+        Assertions.assertTrue(executor.awaitTermination(5, TimeUnit.SECONDS));
+    }
+
+    @Test
+    public void testSingleProducerMultipleConsumers() throws InterruptedException {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(50);
+        int numConsumers = 4;
+        int totalItems = 1000;
+        CountDownLatch doneLatch = new CountDownLatch(numConsumers);
+        AtomicInteger consumedCount = new AtomicInteger(0);
+
+        ExecutorService executor = Executors.newFixedThreadPool(numConsumers + 1);
+
+        executor.submit(() -> {
+            try {
+                for (int i = 0; i < totalItems; i++) {
+                    queue.enqueue(i);
+                }
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        });
+
+        for (int c = 0; c < numConsumers; c++) {
+            executor.submit(() -> {
+                try {
+                    while (consumedCount.get() < totalItems) {
+                        Integer item = queue.poll();
+                        if (item != null) {
+                            consumedCount.incrementAndGet();
+                        }
+                    }
+                } finally {
+                    doneLatch.countDown();
+                }
+            });
+        }
+
+        Assertions.assertTrue(doneLatch.await(10, TimeUnit.SECONDS));
+        Assertions.assertEquals(totalItems, consumedCount.get());
+        executor.shutdown();
+        Assertions.assertTrue(executor.awaitTermination(5, TimeUnit.SECONDS));
+    }
+
+    @Test
+    public void testBlockingEnqueueWhenFull() throws InterruptedException {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(1);
+        queue.enqueue(1);
+
+        AtomicInteger blockedCount = new AtomicInteger(0);
+        Thread producer = new Thread(() -> {
+            try {
+                queue.enqueue(2);
+                blockedCount.incrementAndGet();
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        });
+        producer.start();
+
+        Thread.sleep(100);
+        Assertions.assertEquals(1, queue.dequeue());
+
+        producer.join(2000);
+        Assertions.assertEquals(1, blockedCount.get());
+        Assertions.assertEquals(2, queue.dequeue());
+    }
+
+    @Test
+    public void testBlockingDequeueWhenEmpty() throws InterruptedException {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(5);
+
+        AtomicInteger result = new AtomicInteger(-1);
+        Thread consumer = new Thread(() -> {
+            try {
+                result.set(queue.dequeue());
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        });
+        consumer.start();
+
+        Thread.sleep(100);
+        queue.enqueue(42);
+
+        consumer.join(2000);
+        Assertions.assertEquals(42, result.get());
+    }
+
+    @Test
+    public void testStressConcurrentAccess() throws InterruptedException {
+        ThreadSafeQueue<Integer> queue = new ThreadSafeQueue<>(10);
+        int numThreads = 8;
+        int opsPerThread = 500;
+        CountDownLatch latch = new CountDownLatch(numThreads);
+        AtomicInteger enqueueCount = new AtomicInteger(0);
+        AtomicInteger dequeueCount = new AtomicInteger(0);
+
+        ExecutorService executor = Executors.newFixedThreadPool(numThreads);
+
+        for (int t = 0; t < numThreads; t++) {
+            final boolean isProducer = t % 2 == 0;
+            executor.submit(() -> {
+                try {
+                    for (int i = 0; i < opsPerThread; i++) {
+                        if (isProducer) {
+                            if (queue.offer(i)) {
+                                enqueueCount.incrementAndGet();
+                            }
+                        } else {
+                            if (queue.poll() != null) {
+                                dequeueCount.incrementAndGet();
+                            }
+                        }
+                    }
+                } finally {
+                    latch.countDown();
+                }
+            });
+        }
+
+        Assertions.assertTrue(latch.await(10, TimeUnit.SECONDS));
+        Assertions.assertTrue(enqueueCount.get() >= dequeueCount.get());
+        Assertions.assertEquals(enqueueCount.get() - dequeueCount.get(), queue.size());
+        executor.shutdown();
+        executor.awaitTermination(5, TimeUnit.SECONDS);
+    }
+}

From 42007c8b495136437c7aa39ecc218e2835853030 Mon Sep 17 00:00:00 2001
From: 07Vineet07 <164660112+07Vineet07@users.noreply.github.com>
Date: Tue, 26 May 2026 14:48:41 +0530
Subject: [PATCH 1262/1338] docs: improve LinearSearch documentation with
 examples and step-by-step explanation (#7435)

---
 .../thealgorithms/searches/LinearSearch.java  | 35 ++++++++++++++++---
 1 file changed, 30 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/LinearSearch.java b/src/main/java/com/thealgorithms/searches/LinearSearch.java
index bd14fe21ea03..c5f6e6ba9776 100644
--- a/src/main/java/com/thealgorithms/searches/LinearSearch.java
+++ b/src/main/java/com/thealgorithms/searches/LinearSearch.java
@@ -10,10 +10,34 @@
  *
  * It works for both sorted and unsorted arrays.
  *
+ * <p>How it works step-by-step:
+ * <ol>
+ *   <li>Start from the first element of the array.</li>
+ *   <li>Compare the current element with the target value.</li>
+ *   <li>If they match, return the current index.</li>
+ *   <li>If they don't match, move to the next element.</li>
+ *   <li>Repeat until the element is found or the array ends.</li>
+ *   <li>If not found, return -1.</li>
+ * </ol>
+ *
+ * <p>Example:
+ * <pre>
+ *   Input array: [5, 3, 8, 1, 9]
+ *   Target: 8
+ *
+ *   Step 1: Compare 5 with 8 → no match, move on
+ *   Step 2: Compare 3 with 8 → no match, move on
+ *   Step 3: Compare 8 with 8 → match found at index 2!
+ *
+ *   Output: 2
+ *
+ *   If target = 7:
+ *   Output: -1 (not found)
+ * </pre>
  * Time Complexity:
- *  - Best case: O(1)
- *  - Average case: O(n)
- *  - Worst case: O(n)
+ *  - Best case: O(1) - target is the first element
+ *  - Average case: O(n) - target is somewhere in the middle
+ *  - Worst case: O(n) - target is last or not present
  *
  * Space Complexity: O(1)
  *
@@ -25,9 +49,10 @@
 public class LinearSearch implements SearchAlgorithm {
 
     /**
-     * Generic Linear search method
+     * Generic Linear search method that searches for a value
+     * in the given array by checking each element one by one.
      *
-     * @param array List to be searched
+     * @param array List to be searched (can be unsorted)
      * @param value Key being searched for
      * @return Location of the key, -1 if array is null or empty, or key not found
      */

From 0905cbe1659c1b47cdba6de1ca89d00d26cdb9ff Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 27 May 2026 23:16:07 +0200
Subject: [PATCH 1263/1338] chore(deps-dev): bump
 org.apache.maven.plugins:maven-surefire-plugin from 3.5.5 to 3.5.6 (#7436)

chore(deps-dev): bump org.apache.maven.plugins:maven-surefire-plugin

Bumps [org.apache.maven.plugins:maven-surefire-plugin](https://github.com/apache/maven-surefire) from 3.5.5 to 3.5.6.
- [Release notes](https://github.com/apache/maven-surefire/releases)
- [Commits](https://github.com/apache/maven-surefire/compare/surefire-3.5.5...surefire-3.5.6)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-surefire-plugin
  dependency-version: 3.5.6
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 3fb0887973e0..b2838cbfb9ec 100644
--- a/pom.xml
+++ b/pom.xml
@@ -61,7 +61,7 @@
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.5.5</version>
+                <version>3.5.6</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>

From 7b1995f872cd86b0de4c20f61ab9ff8b8f642774 Mon Sep 17 00:00:00 2001
From: Piotr Idzik <65706193+vil02@users.noreply.github.com>
Date: Thu, 28 May 2026 20:28:26 +0200
Subject: [PATCH 1264/1338] chore: use `srz-zumix/setup-infer` (#7437)

---
 .github/workflows/infer.yml | 32 +++-----------------------------
 .inferconfig                |  1 +
 2 files changed, 4 insertions(+), 29 deletions(-)

diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index 9d4dcf63000b..fbc0f1f1bc7f 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -23,34 +23,8 @@ jobs:
           java-version: 21
           distribution: 'temurin'
 
-      - name: Set up OCaml
-        uses: ocaml/setup-ocaml@v3
-        with:
-          ocaml-compiler: 5
-
-      - name: Get current year/weak
-        run: echo "year_week=$(date +'%Y_%U')" >> $GITHUB_ENV
-
-      - name: Cache infer build
-        id: cache-infer
-        uses: actions/cache@v5
-        with:
-          path: infer
-          key: ${{ runner.os }}-infer-${{ env.year_week }}
-
-      - name: Build infer
-        if: steps.cache-infer.outputs.cache-hit != 'true'
-        run: |
-          cd ..
-          git clone https://github.com/facebook/infer.git
-          cd infer
-          git checkout 02c2c43b71e4c5110c0be841e66153942fda06c9
-          ./build-infer.sh java
-          cp -r infer ../Java
-
-      - name: Add infer to PATH
-        run: |
-          echo "infer/bin" >> $GITHUB_PATH
+      - name: Set up inferAdd commentMore actions
+        uses: srz-zumix/setup-infer@v1
 
       - name: Display infer version
         run: |
@@ -60,5 +34,5 @@ jobs:
       - name: Run infer
         run: |
           mvn clean
-          infer --fail-on-issue  --print-logs --no-progress-bar -- mvn test
+          infer --java-version 21 --fail-on-issue  --print-logs --no-progress-bar -- mvn test
 ...
diff --git a/.inferconfig b/.inferconfig
index 239172177b38..cf26212feac5 100644
--- a/.inferconfig
+++ b/.inferconfig
@@ -21,6 +21,7 @@
         "src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java",
         "src/test/java/com/thealgorithms/datastructures/trees/KDTreeTest.java",
         "src/test/java/com/thealgorithms/datastructures/trees/LazySegmentTreeTest.java",
+        "src/test/java/com/thealgorithms/dynamicprogramming/DamerauLevenshteinDistanceTest.java",
         "src/test/java/com/thealgorithms/others/HuffmanTest.java",
         "src/test/java/com/thealgorithms/searches/QuickSelectTest.java",
         "src/test/java/com/thealgorithms/stacks/PostfixToInfixTest.java",

From 978a3063ea44002e8f820e8553b6659a350e47ac Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sun, 31 May 2026 22:21:18 +0200
Subject: [PATCH 1265/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.4.2 to 13.5.0 (#7441)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.4.2 to 13.5.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.4.2...checkstyle-13.5.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.5.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index b2838cbfb9ec..1cd864ff23f2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.4.2</version>
+                    <version>13.5.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 5feaba6698250e674f1164647b966cc2d254beee Mon Sep 17 00:00:00 2001
From: sawaleparas <parassawale02@gmail.com>
Date: Thu, 4 Jun 2026 03:13:55 +0530
Subject: [PATCH 1266/1338] test: refactor MergeSortedArrayListTest using JUnit
 5 parameterized tests (#7445)

* test: upgrade MergeSortedArrayListTest to use JUnit 5 parameterized tests

* style: strip trailing whitespace and add trailing newline via IDE

* style: align layout with clang-format rules

* style: collapse stream arguments to single lines for clang

* style: fix line wrapping length for clang linter

---------

Co-authored-by: psawale <parassawale9421@gmail.com>
---
 .../lists/MergeSortedArrayListTest.java       | 93 +++++--------------
 1 file changed, 23 insertions(+), 70 deletions(-)

diff --git a/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java
index 5483bbcd0394..4390c0f5f2eb 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/MergeSortedArrayListTest.java
@@ -2,98 +2,51 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class MergeSortedArrayListTest {
 
-    @Test
-    void testMergeTwoSortedLists() {
-        List<Integer> listA = Arrays.asList(1, 3, 5, 7, 9);
-        List<Integer> listB = Arrays.asList(2, 4, 6, 8, 10);
+    @ParameterizedTest(name = "{3}")
+    @MethodSource("provideMergeTestData")
+    void testMergeParameterizedScenarios(List<Integer> listA, List<Integer> listB, List<Integer> expected, String scenarioName) {
         List<Integer> result = new ArrayList<>();
-
         MergeSortedArrayList.merge(listA, listB, result);
-
-        List<Integer> expected = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
-        assertEquals(expected, result, "Merged list should be sorted and contain all elements from both input lists.");
+        assertEquals(expected, result, () -> "Failed scenario: " + scenarioName);
     }
 
-    @Test
-    void testMergeWithEmptyList() {
-        List<Integer> listA = Arrays.asList(1, 2, 3);
-        List<Integer> listB = new ArrayList<>(); // Empty list
-        List<Integer> result = new ArrayList<>();
-
-        MergeSortedArrayList.merge(listA, listB, result);
-
-        List<Integer> expected = Arrays.asList(1, 2, 3);
-        assertEquals(expected, result, "Merged list should match listA when listB is empty.");
-    }
-
-    @Test
-    void testMergeWithBothEmptyLists() {
-        List<Integer> listA = new ArrayList<>(); // Empty list
-        List<Integer> listB = new ArrayList<>(); // Empty list
-        List<Integer> result = new ArrayList<>();
-
-        MergeSortedArrayList.merge(listA, listB, result);
-
-        assertTrue(result.isEmpty(), "Merged list should be empty when both input lists are empty.");
+    private static Stream<Arguments> provideMergeTestData() {
+        return Stream.of(Arguments.of(Arrays.asList(1, 3, 5, 7, 9), Arrays.asList(2, 4, 6, 8, 10), Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10), "Standard alternating sorted lists"), Arguments.of(Arrays.asList(1, 2, 3), new ArrayList<>(), Arrays.asList(1, 2, 3), "Merge with empty second list"),
+            Arguments.of(new ArrayList<>(), Arrays.asList(4, 5, 6), Arrays.asList(4, 5, 6), "Merge with empty first list"), Arguments.of(new ArrayList<>(), new ArrayList<>(), new ArrayList<>(), "Merge with both lists empty"),
+            Arguments.of(Arrays.asList(1, 2, 2, 3), Arrays.asList(2, 3, 4), Arrays.asList(1, 2, 2, 2, 3, 3, 4), "Handling duplicate elements gracefully"),
+            Arguments.of(Arrays.asList(-3, -1, 2), Arrays.asList(-2, 0, 3), Arrays.asList(-3, -2, -1, 0, 2, 3), "Handling negative numbers mixed with positive numbers"));
     }
 
     @Test
-    void testMergeWithDuplicateElements() {
-        List<Integer> listA = Arrays.asList(1, 2, 2, 3);
-        List<Integer> listB = Arrays.asList(2, 3, 4);
+    void testMergeThrowsExceptionWhenListAIsNull() {
+        List<Integer> listB = Arrays.asList(1, 2, 3);
         List<Integer> result = new ArrayList<>();
-
-        MergeSortedArrayList.merge(listA, listB, result);
-
-        List<Integer> expected = Arrays.asList(1, 2, 2, 2, 3, 3, 4);
-        assertEquals(expected, result, "Merged list should correctly handle and include duplicate elements.");
+        assertThrows(NullPointerException.class, () -> MergeSortedArrayList.merge(null, listB, result));
     }
 
     @Test
-    void testMergeWithNegativeAndPositiveNumbers() {
-        List<Integer> listA = Arrays.asList(-3, -1, 2);
-        List<Integer> listB = Arrays.asList(-2, 0, 3);
+    void testMergeThrowsExceptionWhenListBIsNull() {
+        List<Integer> listA = Arrays.asList(1, 2, 3);
         List<Integer> result = new ArrayList<>();
-
-        MergeSortedArrayList.merge(listA, listB, result);
-
-        List<Integer> expected = Arrays.asList(-3, -2, -1, 0, 2, 3);
-        assertEquals(expected, result, "Merged list should correctly handle negative and positive numbers.");
+        assertThrows(NullPointerException.class, () -> MergeSortedArrayList.merge(listA, null, result));
     }
 
     @Test
-    void testMergeThrowsExceptionOnNullInput() {
-        List<Integer> listA = null;
-        List<Integer> listB = Arrays.asList(1, 2, 3);
-        List<Integer> result = new ArrayList<>();
-
-        List<Integer> finalListB = listB;
-        List<Integer> finalListA = listA;
-        List<Integer> finalResult = result;
-        assertThrows(NullPointerException.class, () -> MergeSortedArrayList.merge(finalListA, finalListB, finalResult), "Should throw NullPointerException if any input list is null.");
-
-        listA = Arrays.asList(1, 2, 3);
-        listB = null;
-        List<Integer> finalListA1 = listA;
-        List<Integer> finalListB1 = listB;
-        List<Integer> finalResult1 = result;
-        assertThrows(NullPointerException.class, () -> MergeSortedArrayList.merge(finalListA1, finalListB1, finalResult1), "Should throw NullPointerException if any input list is null.");
-
-        listA = Arrays.asList(1, 2, 3);
-        listB = Arrays.asList(4, 5, 6);
-        result = null;
-        List<Integer> finalListA2 = listA;
-        List<Integer> finalListB2 = listB;
-        List<Integer> finalResult2 = result;
-        assertThrows(NullPointerException.class, () -> MergeSortedArrayList.merge(finalListA2, finalListB2, finalResult2), "Should throw NullPointerException if the result collection is null.");
+    void testMergeThrowsExceptionWhenResultCollectionIsNull() {
+        List<Integer> listA = Arrays.asList(1, 2, 3);
+        List<Integer> listB = Arrays.asList(4, 5, 6);
+        assertThrows(NullPointerException.class, () -> MergeSortedArrayList.merge(listA, listB, null));
     }
 }

From cecfad934137d44e0a915052c4b09f5451bbb96c Mon Sep 17 00:00:00 2001
From: Md Mushfiqur Rahim <20mahin2020@gmail.com>
Date: Wed, 3 Jun 2026 14:47:15 -0700
Subject: [PATCH 1267/1338] feat(matrix): add QR decomposition algorithm using
 Gram-Schmidt process (#7427)

* feat(matrix): add QR decomposition algorithm using Gram-Schmidt process

Decomposes a matrix A into an orthogonal matrix Q and an upper triangular
matrix R such that A = Q * R.

### What This Adds

**QRDecomposition.java** - Main algorithm implementation:
- `decompose()` - Performs QR factorization using the Gram-Schmidt process
- Returns a QR object containing both Q (orthogonal) and R (upper triangular) matrices
- Validates input matrix using MatrixUtil.validateInputMatrix()
- Throws ArithmeticException for rank-deficient matrices

**QRDecompositionTest.java** - Unit tests:
- Tests for 2x2 and 3x3 matrix decomposition
- Verifies Q * R reconstruction equals original matrix
- Validates Q columns are orthonormal
- Confirms R is upper triangular
- Tests identity matrix decomposition
- Tests rank-deficient matrix rejection
- Tests null and empty matrix rejection

### Algorithm

The Gram-Schmidt process orthogonalizes columns iteratively:
- For each column j, subtract projections onto previous orthogonal vectors
- Normalize to get j-th column of Q
- Store coefficients in R[i][j]

Time: O(m*n^2) | Space: O(m*n + n^2)

### Reference

https://en.wikipedia.org/wiki/QR_decomposition

* fix(matrix): inline matrix validation to avoid cross-package dependency

MatrixUtil is in com.thealgorithms.matrix.utils package which causes
compilation errors when referenced from com.thealgorithms.matrix.
Inlined the validation logic (validateInputMatrix, hasValidRows,
isJaggedMatrix) directly into QRDecomposition to resolve the issue.
---
 .../thealgorithms/matrix/QRDecomposition.java | 149 ++++++++++++++++++
 .../matrix/QRDecompositionTest.java           | 115 ++++++++++++++
 2 files changed, 264 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/matrix/QRDecomposition.java
 create mode 100644 src/test/java/com/thealgorithms/matrix/QRDecompositionTest.java

diff --git a/src/main/java/com/thealgorithms/matrix/QRDecomposition.java b/src/main/java/com/thealgorithms/matrix/QRDecomposition.java
new file mode 100644
index 000000000000..45f56bc14729
--- /dev/null
+++ b/src/main/java/com/thealgorithms/matrix/QRDecomposition.java
@@ -0,0 +1,149 @@
+package com.thealgorithms.matrix;
+
+/**
+ * @brief Implementation of QR Decomposition using the Gram-Schmidt process
+ * @details Decomposes a matrix A into an orthogonal matrix Q and an upper
+ * triangular matrix R such that A = Q * R. The Gram-Schmidt process
+ * orthogonalizes the columns of A to produce Q, and R is computed as Q^T * A.
+ * This decomposition is useful for solving linear least squares problems,
+ * eigenvalue computations, and numerical stability in linear algebra.
+ * @see <a href="https://en.wikipedia.org/wiki/QR_decomposition">QR Decomposition</a>
+ */
+public final class QRDecomposition {
+
+    private QRDecomposition() {
+    }
+
+    /**
+     * A helper class to store both Q and R matrices
+     */
+    public static class QR {
+        private final double[][] q;
+        private final double[][] r;
+
+        QR(double[][] q, double[][] r) {
+            this.q = q;
+            this.r = r;
+        }
+
+        public double[][] getQ() {
+            return q;
+        }
+
+        public double[][] getR() {
+            return r;
+        }
+    }
+
+    /**
+     * @brief Performs QR decomposition on a matrix using the Gram-Schmidt process
+     * @param matrix the input matrix (m x n)
+     * @return QR object containing orthogonal matrix Q (m x n) and upper triangular matrix R (n x n)
+     * @throws IllegalArgumentException if the matrix is null, empty, or has invalid rows
+     */
+    public static QR decompose(double[][] matrix) {
+        validateInputMatrix(matrix);
+
+        int m = matrix.length;
+        int n = matrix[0].length;
+
+        double[][] q = new double[m][n];
+        double[][] r = new double[n][n];
+
+        for (int j = 0; j < n; j++) {
+            double[] v = getColumn(matrix, j);
+
+            for (int i = 0; i < j; i++) {
+                double[] qi = getColumn(q, i);
+                r[i][j] = dotProduct(qi, v);
+                v = subtractVectors(v, scalarMultiply(qi, r[i][j]));
+            }
+
+            r[j][j] = norm(v);
+            if (r[j][j] == 0) {
+                throw new ArithmeticException("Matrix is rank deficient. Cannot perform QR decomposition.");
+            }
+            double[] qj = scalarMultiply(v, 1.0 / r[j][j]);
+            setColumn(q, j, qj);
+        }
+
+        return new QR(q, r);
+    }
+
+    private static double[] getColumn(double[][] matrix, int col) {
+        int m = matrix.length;
+        double[] column = new double[m];
+        for (int i = 0; i < m; i++) {
+            column[i] = matrix[i][col];
+        }
+        return column;
+    }
+
+    private static void setColumn(double[][] matrix, int col, double[] column) {
+        for (int i = 0; i < matrix.length; i++) {
+            matrix[i][col] = column[i];
+        }
+    }
+
+    private static double dotProduct(double[] a, double[] b) {
+        double sum = 0;
+        for (int i = 0; i < a.length; i++) {
+            sum += a[i] * b[i];
+        }
+        return sum;
+    }
+
+    private static double[] subtractVectors(double[] a, double[] b) {
+        double[] result = new double[a.length];
+        for (int i = 0; i < a.length; i++) {
+            result[i] = a[i] - b[i];
+        }
+        return result;
+    }
+
+    private static double[] scalarMultiply(double[] v, double scalar) {
+        double[] result = new double[v.length];
+        for (int i = 0; i < v.length; i++) {
+            result[i] = v[i] * scalar;
+        }
+        return result;
+    }
+
+    private static double norm(double[] v) {
+        return Math.sqrt(dotProduct(v, v));
+    }
+
+    private static void validateInputMatrix(double[][] matrix) {
+        if (matrix == null) {
+            throw new IllegalArgumentException("The input matrix cannot be null");
+        }
+        if (matrix.length == 0) {
+            throw new IllegalArgumentException("The input matrix cannot be empty");
+        }
+        if (!hasValidRows(matrix)) {
+            throw new IllegalArgumentException("The input matrix cannot have null or empty rows");
+        }
+        if (isJaggedMatrix(matrix)) {
+            throw new IllegalArgumentException("The input matrix cannot be jagged");
+        }
+    }
+
+    private static boolean hasValidRows(double[][] matrix) {
+        for (double[] row : matrix) {
+            if (row == null || row.length == 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private static boolean isJaggedMatrix(double[][] matrix) {
+        int numColumns = matrix[0].length;
+        for (double[] row : matrix) {
+            if (row.length != numColumns) {
+                return true;
+            }
+        }
+        return false;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/matrix/QRDecompositionTest.java b/src/test/java/com/thealgorithms/matrix/QRDecompositionTest.java
new file mode 100644
index 000000000000..adc8fb717e57
--- /dev/null
+++ b/src/test/java/com/thealgorithms/matrix/QRDecompositionTest.java
@@ -0,0 +1,115 @@
+package com.thealgorithms.matrix;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class QRDecompositionTest {
+
+    private static final double DELTA = 1e-9;
+
+    @Test
+    public void testQRDecomposition2x2() {
+        double[][] matrix = {{12, -51}, {6, 167}};
+        QRDecomposition.QR qr = QRDecomposition.decompose(matrix);
+        double[][] q = qr.getQ();
+        double[][] r = qr.getR();
+
+        double[][] reconstructed = multiplyMatrices(q, r);
+        for (int i = 0; i < matrix.length; i++) {
+            assertArrayEquals(matrix[i], reconstructed[i], DELTA);
+        }
+    }
+
+    @Test
+    public void testQRDecomposition3x3() {
+        double[][] matrix = {{1, 1, 0}, {1, 0, 1}, {0, 1, 1}};
+        QRDecomposition.QR qr = QRDecomposition.decompose(matrix);
+        double[][] q = qr.getQ();
+        double[][] r = qr.getR();
+
+        double[][] reconstructed = multiplyMatrices(q, r);
+        for (int i = 0; i < matrix.length; i++) {
+            assertArrayEquals(matrix[i], reconstructed[i], DELTA);
+        }
+    }
+
+    @Test
+    public void testQROrthogonalColumns() {
+        double[][] matrix = {{1, 1, 0}, {1, 0, 1}, {0, 1, 1}};
+        QRDecomposition.QR qr = QRDecomposition.decompose(matrix);
+        double[][] q = qr.getQ();
+
+        for (int i = 0; i < q[0].length; i++) {
+            for (int j = i; j < q[0].length; j++) {
+                double dot = 0;
+                for (int k = 0; k < q.length; k++) {
+                    dot += q[k][i] * q[k][j];
+                }
+                if (i == j) {
+                    assertArrayEquals(new double[] {1.0}, new double[] {dot}, DELTA);
+                } else {
+                    assertArrayEquals(new double[] {0.0}, new double[] {dot}, DELTA);
+                }
+            }
+        }
+    }
+
+    @Test
+    public void testRIsUpperTriangular() {
+        double[][] matrix = {{12, -51}, {6, 167}};
+        QRDecomposition.QR qr = QRDecomposition.decompose(matrix);
+        double[][] r = qr.getR();
+
+        for (int i = 1; i < r.length; i++) {
+            for (int j = 0; j < i; j++) {
+                assertArrayEquals(new double[] {0.0}, new double[] {r[i][j]}, DELTA);
+            }
+        }
+    }
+
+    @Test
+    public void testQRDecompositionIdentityMatrix() {
+        double[][] matrix = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}};
+        QRDecomposition.QR qr = QRDecomposition.decompose(matrix);
+        double[][] q = qr.getQ();
+        double[][] r = qr.getR();
+
+        for (int i = 0; i < matrix.length; i++) {
+            assertArrayEquals(matrix[i], q[i], DELTA);
+            assertArrayEquals(matrix[i], r[i], DELTA);
+        }
+    }
+
+    @Test
+    public void testQRDecompositionRankDeficientThrows() {
+        double[][] matrix = {{1, 2}, {2, 4}};
+        assertThrows(ArithmeticException.class, () -> QRDecomposition.decompose(matrix));
+    }
+
+    @Test
+    public void testQRDecompositionNullMatrixThrows() {
+        assertThrows(IllegalArgumentException.class, () -> QRDecomposition.decompose(null));
+    }
+
+    @Test
+    public void testQRDecompositionEmptyMatrixThrows() {
+        assertThrows(IllegalArgumentException.class, () -> QRDecomposition.decompose(new double[0][0]));
+    }
+
+    private static double[][] multiplyMatrices(double[][] a, double[][] b) {
+        int m = a.length;
+        int n = b[0].length;
+        int k = a[0].length;
+        double[][] result = new double[m][n];
+        for (int i = 0; i < m; i++) {
+            for (int j = 0; j < n; j++) {
+                for (int p = 0; p < k; p++) {
+                    result[i][j] += a[i][p] * b[p][j];
+                }
+            }
+        }
+        return result;
+    }
+}

From e514f728b9ca95f1e0bee2e7798b201815cfb51c Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 6 Jun 2026 00:14:23 +0200
Subject: [PATCH 1268/1338] chore(deps-dev): bump
 org.jacoco:jacoco-maven-plugin from 0.8.14 to 0.8.15 (#7448)

chore(deps-dev): bump org.jacoco:jacoco-maven-plugin

Bumps [org.jacoco:jacoco-maven-plugin](https://github.com/jacoco/jacoco) from 0.8.14 to 0.8.15.
- [Release notes](https://github.com/jacoco/jacoco/releases)
- [Commits](https://github.com/jacoco/jacoco/compare/v0.8.14...v0.8.15)

---
updated-dependencies:
- dependency-name: org.jacoco:jacoco-maven-plugin
  dependency-version: 0.8.15
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 1cd864ff23f2..6edd36f446d8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -82,7 +82,7 @@
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>
-                <version>0.8.14</version>
+                <version>0.8.15</version>
                 <executions>
                     <execution>
                         <goals>

From ae861d6ceabc6921a44e8f188fd778ff06bc7d76 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sun, 7 Jun 2026 13:26:31 +0200
Subject: [PATCH 1269/1338] chore(deps): bump codecov/codecov-action from 6 to
 7 in /.github/workflows (#7449)

chore(deps): bump codecov/codecov-action in /.github/workflows

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 6 to 7.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/codecov/codecov-action/compare/v6...v7)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 1c2c1ef828b7..4b1f0f376e25 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -20,7 +20,7 @@ jobs:
         if: >-
           github.event_name == 'pull_request' &&
           github.event.pull_request.head.repo.full_name != github.repository
-        uses: codecov/codecov-action@v6
+        uses: codecov/codecov-action@v7
         with:
           fail_ci_if_error: true
       - name: Upload coverage to codecov (with token)
@@ -28,7 +28,7 @@ jobs:
           github.repository == 'TheAlgorithms/Java' &&
           (github.event_name != 'pull_request' ||
           github.event.pull_request.head.repo.full_name == github.repository)
-        uses: codecov/codecov-action@v6
+        uses: codecov/codecov-action@v7
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true

From d792409c4e2dddb612d1f4e96cc3a6bdd3b10dea Mon Sep 17 00:00:00 2001
From: Sai Chandu Vallaboju <vallabojus1@udayton.edu>
Date: Wed, 10 Jun 2026 03:41:06 -0400
Subject: [PATCH 1270/1338] Rename and relocate trie autocomplete
 implementation (#7459)

refactor: rename trie autocomplete implementation
---
 pmd-exclude.properties                                        | 2 +-
 .../trees/TrieAutocomplete.java}                              | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)
 rename src/main/java/com/thealgorithms/{others/Implementing_auto_completing_features_using_trie.java => datastructures/trees/TrieAutocomplete.java} (98%)

diff --git a/pmd-exclude.properties b/pmd-exclude.properties
index 64562c524728..26653d9dc17b 100644
--- a/pmd-exclude.properties
+++ b/pmd-exclude.properties
@@ -86,7 +86,7 @@ com.thealgorithms.others.MosAlgorithm=UselessMainMethod
 com.thealgorithms.others.PageRank=UselessMainMethod,UselessParentheses
 com.thealgorithms.others.PerlinNoise=UselessMainMethod,UselessParentheses
 com.thealgorithms.others.QueueUsingTwoStacks=UselessParentheses
-com.thealgorithms.others.Trieac=UselessMainMethod,UselessParentheses
+com.thealgorithms.datastructures.trees.TrieAutocomplete=UselessMainMethod,UselessParentheses
 com.thealgorithms.others.Verhoeff=UnnecessaryFullyQualifiedName,UselessMainMethod
 com.thealgorithms.recursion.DiceThrower=UselessMainMethod
 com.thealgorithms.searches.HowManyTimesRotated=UselessMainMethod
diff --git a/src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java b/src/main/java/com/thealgorithms/datastructures/trees/TrieAutocomplete.java
similarity index 98%
rename from src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java
rename to src/main/java/com/thealgorithms/datastructures/trees/TrieAutocomplete.java
index 7a1a7aadd805..624e3d65bfc1 100644
--- a/src/main/java/com/thealgorithms/others/Implementing_auto_completing_features_using_trie.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/TrieAutocomplete.java
@@ -1,8 +1,8 @@
-package com.thealgorithms.others;
+package com.thealgorithms.datastructures.trees;
 
 // Java Program to implement Auto-Complete
 // Feature using Trie
-class Trieac {
+class TrieAutocomplete {
 
     // Alphabet size (# of symbols)
     public static final int ALPHABET_SIZE = 26;

From 34079f0aa02d8f4564a21fabd4326f3fd3eb8a8e Mon Sep 17 00:00:00 2001
From: Aman Gupta <amanmacair98@gmail.com>
Date: Wed, 10 Jun 2026 13:17:20 +0530
Subject: [PATCH 1271/1338] =?UTF-8?q?test(dp):=20add=20tests=20for=20Longe?=
 =?UTF-8?q?stPalindromicSubsequence=20and=20remove=20main=E2=80=A6=20(#746?=
 =?UTF-8?q?2)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* test(dp): add tests for LongestPalindromicSubsequence and remove main method

* fix: formatting and style fixes for clang-format compliance

* fix: correct expected values in tests and add missing EOF newline

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../LongestPalindromicSubsequence.java        | 72 ++++++++-----------
 .../LongestPalindromicSubsequenceTest.java    | 54 ++++++++++++++
 2 files changed, 82 insertions(+), 44 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequenceTest.java

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java
index 0b40d4559341..5c8a6a953f83 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequence.java
@@ -1,58 +1,42 @@
 package com.thealgorithms.dynamicprogramming;
 
 /**
- * Algorithm explanation
- * https://www.educative.io/edpresso/longest-palindromic-subsequence-algorithm
+ * Longest Palindromic Subsequence algorithm.
+ * A palindromic subsequence is a subsequence that reads the same forwards and backwards.
+ * This implementation finds the longest such subsequence by computing the LCS of the
+ * original string and its reverse.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Longest_palindromic_subsequence">Wikipedia</a>
  */
 public final class LongestPalindromicSubsequence {
     private LongestPalindromicSubsequence() {
     }
 
-    public static void main(String[] args) {
-        String a = "BBABCBCAB";
-        String b = "BABCBAB";
-
-        String aLPS = lps(a);
-        String bLPS = lps(b);
-
-        System.out.println(a + " => " + aLPS);
-        System.out.println(b + " => " + bLPS);
-    }
-
-    public static String lps(String original) throws IllegalArgumentException {
-        StringBuilder reverse = new StringBuilder(original);
-        reverse = reverse.reverse();
-        return recursiveLPS(original, reverse.toString());
+    /**
+     * Returns the longest palindromic subsequence of the given string.
+     *
+     * @param original the input string
+     * @return the longest palindromic subsequence
+     * @throws IllegalArgumentException if the input string is null
+     */
+    public static String lps(String original) {
+        if (original == null) {
+            throw new IllegalArgumentException("Input string must not be null");
+        }
+        String reverse = new StringBuilder(original).reverse().toString();
+        return recursiveLPS(original, reverse);
     }
 
     private static String recursiveLPS(String original, String reverse) {
-        String bestResult = "";
-
-        // no more chars, then return empty
-        if (original.length() == 0 || reverse.length() == 0) {
-            bestResult = "";
-        } else {
-            // if the last chars match, then remove it from both strings and recur
-            if (original.charAt(original.length() - 1) == reverse.charAt(reverse.length() - 1)) {
-                String bestSubResult = recursiveLPS(original.substring(0, original.length() - 1), reverse.substring(0, reverse.length() - 1));
-
-                bestResult = reverse.charAt(reverse.length() - 1) + bestSubResult;
-            } else {
-                // otherwise (1) ignore the last character of reverse, and recur on original and
-                // updated reverse again (2) ignore the last character of original and recur on the
-                // updated original and reverse again then select the best result from these two
-                // subproblems.
-
-                String bestSubResult1 = recursiveLPS(original, reverse.substring(0, reverse.length() - 1));
-                String bestSubResult2 = recursiveLPS(original.substring(0, original.length() - 1), reverse);
-                if (bestSubResult1.length() > bestSubResult2.length()) {
-                    bestResult = bestSubResult1;
-                } else {
-                    bestResult = bestSubResult2;
-                }
-            }
+        if (original.isEmpty() || reverse.isEmpty()) {
+            return "";
         }
-
-        return bestResult;
+        if (original.charAt(original.length() - 1) == reverse.charAt(reverse.length() - 1)) {
+            String bestSubResult = recursiveLPS(original.substring(0, original.length() - 1), reverse.substring(0, reverse.length() - 1));
+            return reverse.charAt(reverse.length() - 1) + bestSubResult;
+        }
+        String sub1 = recursiveLPS(original, reverse.substring(0, reverse.length() - 1));
+        String sub2 = recursiveLPS(original.substring(0, original.length() - 1), reverse);
+        return sub1.length() >= sub2.length() ? sub1 : sub2;
     }
 }
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequenceTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequenceTest.java
new file mode 100644
index 000000000000..a1ee624e94d2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/LongestPalindromicSubsequenceTest.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class LongestPalindromicSubsequenceTest {
+
+    @ParameterizedTest
+    @CsvSource({"BBABCBCAB, BACBCAB", "BABCBAB, BABCBAB", "A, A", "AA, AA", "AB, B"})
+    void testLpsKnownCases(String input, String expectedLps) {
+        assertEquals(expectedLps, LongestPalindromicSubsequence.lps(input));
+    }
+
+    @Test
+    void testLpsEmptyString() {
+        assertEquals("", LongestPalindromicSubsequence.lps(""));
+    }
+
+    @Test
+    void testLpsSingleCharacter() {
+        assertEquals("Z", LongestPalindromicSubsequence.lps("Z"));
+    }
+
+    @Test
+    void testLpsAllSameCharacters() {
+        assertEquals("AAAA", LongestPalindromicSubsequence.lps("AAAA"));
+    }
+
+    @Test
+    void testLpsAlreadyPalindrome() {
+        assertEquals("RACECAR", LongestPalindromicSubsequence.lps("RACECAR"));
+    }
+
+    @Test
+    void testLpsNoRepeatingCharacters() {
+        assertEquals(1, LongestPalindromicSubsequence.lps("ABCDE").length());
+    }
+
+    @Test
+    void testLpsNullThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> { LongestPalindromicSubsequence.lps(null); });
+    }
+
+    @Test
+    void testLpsResultIsActuallyPalindrome() {
+        String result = LongestPalindromicSubsequence.lps("BBABCBCAB");
+        String reversed = new StringBuilder(result).reverse().toString();
+        assertEquals(result, reversed);
+    }
+}

From 6fbbc9407a9432b31edb525be87fc62a2aa80c20 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 10 Jun 2026 23:55:07 +0200
Subject: [PATCH 1272/1338] chore(deps-dev): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.9.8.3 to 4.10.2.0 (#7465)

chore(deps-dev): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.9.8.3 to 4.10.2.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.9.8.3...spotbugs-maven-plugin-4.10.2.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.10.2.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 6edd36f446d8..e54b83399e9f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -119,7 +119,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.9.8.3</version>
+                <version>4.10.2.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>

From 0388455908a643d7e69a2247fec191357338fa6f Mon Sep 17 00:00:00 2001
From: Rosander0 <astereen.0107@gmail.com>
Date: Mon, 15 Jun 2026 01:49:56 +0530
Subject: [PATCH 1273/1338] Add LongestCommonSubstring Implementation (#7464)

feat: add LongestCommonSubstring implementation
---
 .../strings/LongestCommonSubstring.java       | 55 +++++++++++++++++++
 .../strings/LongestCommonSubstringTest.java   | 36 ++++++++++++
 2 files changed, 91 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/LongestCommonSubstring.java
 create mode 100644 src/test/java/com/thealgorithms/strings/LongestCommonSubstringTest.java

diff --git a/src/main/java/com/thealgorithms/strings/LongestCommonSubstring.java b/src/main/java/com/thealgorithms/strings/LongestCommonSubstring.java
new file mode 100644
index 000000000000..b2190316aff2
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/LongestCommonSubstring.java
@@ -0,0 +1,55 @@
+package com.thealgorithms.strings;
+
+/**
+ * Longest Common Substring finds the longest string that is a
+ * contiguous substring of two input strings.
+ * Example: "abcdef" and "zcdemf" -> "cde"
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Longest_common_substring">
+ *     Wikipedia: Longest Common Substring</a>
+ *
+ * author: Vraj Prajapati @Rosander0
+ */
+public final class LongestCommonSubstring {
+
+    private LongestCommonSubstring() {
+        // Utility class
+    }
+
+    /**
+     * Finds the longest common substring of two strings.
+     *
+     * @param a First input string
+     * @param b Second input string
+     * @return The longest common substring, or empty string if none exists.
+     *     If multiple substrings share the maximum length, the first one found is returned.
+     */
+    public static String longestCommonSubstring(final String a, final String b) {
+        if (a == null || b == null || a.isEmpty() || b.isEmpty()) {
+            return "";
+        }
+
+        int[][] dp = new int[a.length() + 1][b.length() + 1];
+        int maxLength = 0;
+        int endIndex = 0;
+
+        for (int i = 1; i <= a.length(); i++) {
+            for (int j = 1; j <= b.length(); j++) {
+                if (a.charAt(i - 1) == b.charAt(j - 1)) {
+                    dp[i][j] = dp[i - 1][j - 1] + 1;
+                    if (dp[i][j] > maxLength) {
+                        maxLength = dp[i][j];
+                        endIndex = i;
+                    }
+                } else {
+                    dp[i][j] = 0;
+                }
+            }
+        }
+
+        if (maxLength == 0) {
+            return "";
+        }
+        return a.substring(endIndex - maxLength, endIndex);
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/LongestCommonSubstringTest.java b/src/test/java/com/thealgorithms/strings/LongestCommonSubstringTest.java
new file mode 100644
index 000000000000..e54abcf2f1f3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/LongestCommonSubstringTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.strings;
+// author: Vraj Prajapati @Rosander0
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class LongestCommonSubstringTest {
+
+    @Test
+    public void testNullOrEmptyInputs() {
+        assertEquals("", LongestCommonSubstring.longestCommonSubstring(null, "abc"));
+        assertEquals("", LongestCommonSubstring.longestCommonSubstring("abc", null));
+        assertEquals("", LongestCommonSubstring.longestCommonSubstring("", "abc"));
+        assertEquals("", LongestCommonSubstring.longestCommonSubstring("abc", ""));
+    }
+
+    @Test
+    public void testNormalSubstrings() {
+        assertEquals("cde", LongestCommonSubstring.longestCommonSubstring("abcdef", "zcdemf"));
+        assertEquals("abc", LongestCommonSubstring.longestCommonSubstring("abc", "abc"));
+        assertEquals("cdef", LongestCommonSubstring.longestCommonSubstring("abcdef", "cdefgh"));
+    }
+
+    @Test
+    public void testSingleCharacterAndNoMatch() {
+        assertEquals("a", LongestCommonSubstring.longestCommonSubstring("a", "a"));
+        assertEquals("", LongestCommonSubstring.longestCommonSubstring("abc", "xyz"));
+    }
+
+    @Test
+    public void testMultipleMatchesFirstLongest() {
+        // Keeps the first matched longest substring when lengths are tied
+        assertEquals("abc", LongestCommonSubstring.longestCommonSubstring("abcXdef", "abcYdef"));
+    }
+}

From bf8f3bd490d78e1ed8f97fa9b851ce1d8f85e6c5 Mon Sep 17 00:00:00 2001
From: Abdullah Shah <syedabdullahshah086@gmail.com>
Date: Mon, 15 Jun 2026 13:59:03 +0500
Subject: [PATCH 1274/1338] feat: add count distinct elements in window
 algorithm (#7463)

* feat: add count distinct elements in window algorithm

* feat: add CountDistinctElementsInWindow

* fix: address CI issues
---
 .../CountDistinctElementsInWindow.java        | 57 +++++++++++++++++++
 .../CountDistinctElementsInWindowTest.java    | 34 +++++++++++
 2 files changed, 91 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/slidingwindow/CountDistinctElementsInWindow.java
 create mode 100644 src/test/java/com/thealgorithms/slidingwindow/CountDistinctElementsInWindowTest.java

diff --git a/src/main/java/com/thealgorithms/slidingwindow/CountDistinctElementsInWindow.java b/src/main/java/com/thealgorithms/slidingwindow/CountDistinctElementsInWindow.java
new file mode 100644
index 000000000000..19e573437f6d
--- /dev/null
+++ b/src/main/java/com/thealgorithms/slidingwindow/CountDistinctElementsInWindow.java
@@ -0,0 +1,57 @@
+package com.thealgorithms.slidingwindow;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Counts the number of distinct elements in every window of size k.
+ *
+ * @see <a href="https://www.geeksforgeeks.org/count-distinct-elements-in-every-window-of-size-k/">Reference</a>
+ */
+public final class CountDistinctElementsInWindow {
+
+    private CountDistinctElementsInWindow() {
+    }
+
+    /**
+     * Returns an array where each element is the count of distinct
+     * elements in the corresponding window of size k.
+     *
+     * @param arr the input array
+     * @param k   the window size
+     * @return array of distinct element counts per window
+     */
+    public static int[] countDistinct(int[] arr, int k) {
+        if (arr == null || arr.length == 0 || k <= 0 || k > arr.length) {
+            throw new IllegalArgumentException("Invalid input");
+        }
+
+        int n = arr.length;
+        int[] result = new int[n - k + 1];
+        Map<Integer, Integer> freqMap = new HashMap<>();
+
+        for (int i = 0; i < k; i++) {
+            freqMap.merge(arr[i], 1, Integer::sum);
+        }
+        result[0] = freqMap.size();
+
+        for (int i = k; i < n; i++) {
+            freqMap.merge(arr[i], 1, Integer::sum);
+
+            int outgoing = arr[i - k];
+
+            Integer count = freqMap.get(outgoing);
+            if (count != null) {
+                if (count == 1) {
+                    freqMap.remove(outgoing);
+                } else {
+                    freqMap.put(outgoing, count - 1);
+                }
+            }
+
+            result[i - k + 1] = freqMap.size();
+        }
+
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/slidingwindow/CountDistinctElementsInWindowTest.java b/src/test/java/com/thealgorithms/slidingwindow/CountDistinctElementsInWindowTest.java
new file mode 100644
index 000000000000..a6931bca99d2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/slidingwindow/CountDistinctElementsInWindowTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.slidingwindow;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class CountDistinctElementsInWindowTest {
+
+    @Test
+    public void testBasicCase() {
+        assertArrayEquals(new int[] {3, 2, 2}, CountDistinctElementsInWindow.countDistinct(new int[] {1, 2, 3, 2, 3}, 3));
+    }
+
+    @Test
+    public void testAllSame() {
+        assertArrayEquals(new int[] {1, 1, 1}, CountDistinctElementsInWindow.countDistinct(new int[] {2, 2, 2, 2}, 2));
+    }
+
+    @Test
+    public void testAllDistinct() {
+        assertArrayEquals(new int[] {3, 3}, CountDistinctElementsInWindow.countDistinct(new int[] {1, 2, 3, 4}, 3));
+    }
+
+    @Test
+    public void testWindowSizeEqualsArray() {
+        assertArrayEquals(new int[] {4}, CountDistinctElementsInWindow.countDistinct(new int[] {1, 2, 3, 4}, 4));
+    }
+
+    @Test
+    public void testInvalidInput() {
+        assertThrows(IllegalArgumentException.class, () -> CountDistinctElementsInWindow.countDistinct(new int[] {}, 2));
+    }
+}

From b3fcb12b9436a4699f4676c81ccb204c92c70dbc Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 15 Jun 2026 21:56:21 +0200
Subject: [PATCH 1275/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.5.0 to 13.6.0 (#7480)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.5.0 to 13.6.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.5.0...checkstyle-13.6.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index e54b83399e9f..927395112259 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.5.0</version>
+                    <version>13.6.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 8e374d3904e8557c3bb8e9f033a236b0f3e21cc5 Mon Sep 17 00:00:00 2001
From: Rosander0 <astereen.0107@gmail.com>
Date: Thu, 18 Jun 2026 12:53:03 +0530
Subject: [PATCH 1276/1338] Add PerrinNumber Implementation (#7478)

feat: add PerrinNumber implementation
---
 .../com/thealgorithms/maths/PerrinNumber.java | 53 +++++++++++++++++++
 .../thealgorithms/maths/PerrinNumberTest.java | 34 ++++++++++++
 2 files changed, 87 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/PerrinNumber.java
 create mode 100644 src/test/java/com/thealgorithms/maths/PerrinNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/PerrinNumber.java b/src/main/java/com/thealgorithms/maths/PerrinNumber.java
new file mode 100644
index 000000000000..cee45a1c5538
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/PerrinNumber.java
@@ -0,0 +1,53 @@
+package com.thealgorithms.maths;
+// author: Vraj Prajapati @Rosander0
+
+/**
+ * The Perrin Sequence is a sequence of integers defined by the recurrence relation:
+ * P(n) = P(n-2) + P(n-3) with initial values P(0) = 3, P(1) = 0, P(2) = 2.
+ * Example: 3, 0, 2, 3, 2, 5, 5, 7, 10, 12, 17, 22, 29, 39, 51...
+ *
+ * Note: The Perrin Sequence uses the same recurrence relation as the Padovan Sequence
+ * but has different initial values.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Perrin_number">
+ *     Wikipedia: Perrin Number</a>
+ * @see PadovanSequence
+ */
+public final class PerrinNumber {
+
+    private PerrinNumber() {
+        // Utility class
+    }
+
+    /**
+     * Calculates the nth term of the Perrin Sequence.
+     *
+     * @param n the index of the sequence (must be non-negative)
+     * @return the nth term of the Perrin Sequence
+     */
+    public static long perrin(final int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input must be non-negative!");
+        }
+        if (n == 0) {
+            return 3;
+        }
+        if (n == 1) {
+            return 0;
+        }
+        if (n == 2) {
+            return 2;
+        }
+        long a = 3;
+        long b = 0;
+        long c = 2;
+        long result = 0;
+        for (int i = 3; i <= n; i++) {
+            result = a + b;
+            a = b;
+            b = c;
+            c = result;
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/PerrinNumberTest.java b/src/test/java/com/thealgorithms/maths/PerrinNumberTest.java
new file mode 100644
index 000000000000..0ec476dc0641
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/PerrinNumberTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.maths;
+// author: Vraj Prajapati @Rosander0
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class PerrinNumberTest {
+
+    @Test
+    public void testBaseCases() {
+        assertEquals(3, PerrinNumber.perrin(0));
+        assertEquals(0, PerrinNumber.perrin(1));
+        assertEquals(2, PerrinNumber.perrin(2));
+    }
+
+    @Test
+    public void testKnownValues() {
+        assertEquals(3, PerrinNumber.perrin(3));
+        assertEquals(2, PerrinNumber.perrin(4));
+        assertEquals(5, PerrinNumber.perrin(5));
+        assertEquals(5, PerrinNumber.perrin(6));
+        assertEquals(7, PerrinNumber.perrin(7));
+        assertEquals(10, PerrinNumber.perrin(8));
+        assertEquals(12, PerrinNumber.perrin(9));
+        assertEquals(17, PerrinNumber.perrin(10));
+    }
+
+    @Test
+    public void testInvalidInput() {
+        assertThrows(IllegalArgumentException.class, () -> PerrinNumber.perrin(-1));
+    }
+}

From bf0ff70d21df09288d0f9f358798c4902652736a Mon Sep 17 00:00:00 2001
From: Rosander0 <astereen.0107@gmail.com>
Date: Thu, 18 Jun 2026 12:56:56 +0530
Subject: [PATCH 1277/1338] Add JacobsthalNumber Implementation (#7479)

feat: add JacobsthalNumber implementation
---
 .../thealgorithms/maths/JacobsthalNumber.java | 44 +++++++++++++++++++
 .../maths/JacobsthalNumberTest.java           | 34 ++++++++++++++
 2 files changed, 78 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/JacobsthalNumber.java
 create mode 100644 src/test/java/com/thealgorithms/maths/JacobsthalNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/JacobsthalNumber.java b/src/main/java/com/thealgorithms/maths/JacobsthalNumber.java
new file mode 100644
index 000000000000..f4f2e23c3932
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/JacobsthalNumber.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.maths;
+// author: Vraj Prajapati @Rosander0
+
+/**
+ * The Jacobsthal Sequence is a sequence of integers defined by the recurrence relation:
+ * J(n) = J(n-1) + 2*J(n-2) with initial values J(0) = 0, J(1) = 1.
+ * Example: 0, 1, 1, 3, 5, 11, 21, 43, 85, 171, 341...
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Jacobsthal_number">
+ *     Wikipedia: Jacobsthal Number</a>
+ */
+public final class JacobsthalNumber {
+
+    private JacobsthalNumber() {
+        // Utility class
+    }
+
+    /**
+     * Calculates the nth term of the Jacobsthal Sequence.
+     *
+     * @param n the index of the sequence (must be non-negative)
+     * @return the nth term of the Jacobsthal Sequence
+     */
+    public static long jacobsthal(final int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input must be non-negative!");
+        }
+        if (n == 0) {
+            return 0;
+        }
+        if (n == 1) {
+            return 1;
+        }
+        long a = 0;
+        long b = 1;
+        long result = 0;
+        for (int i = 2; i <= n; i++) {
+            result = b + 2 * a;
+            a = b;
+            b = result;
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/JacobsthalNumberTest.java b/src/test/java/com/thealgorithms/maths/JacobsthalNumberTest.java
new file mode 100644
index 000000000000..19558510f916
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/JacobsthalNumberTest.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.maths;
+// author: Vraj Prajapati @Rosander0
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class JacobsthalNumberTest {
+
+    @Test
+    public void testBaseCases() {
+        assertEquals(0, JacobsthalNumber.jacobsthal(0));
+        assertEquals(1, JacobsthalNumber.jacobsthal(1));
+    }
+
+    @Test
+    public void testKnownValues() {
+        assertEquals(1, JacobsthalNumber.jacobsthal(2));
+        assertEquals(3, JacobsthalNumber.jacobsthal(3));
+        assertEquals(5, JacobsthalNumber.jacobsthal(4));
+        assertEquals(11, JacobsthalNumber.jacobsthal(5));
+        assertEquals(21, JacobsthalNumber.jacobsthal(6));
+        assertEquals(43, JacobsthalNumber.jacobsthal(7));
+        assertEquals(85, JacobsthalNumber.jacobsthal(8));
+        assertEquals(171, JacobsthalNumber.jacobsthal(9));
+        assertEquals(341, JacobsthalNumber.jacobsthal(10));
+    }
+
+    @Test
+    public void testInvalidInput() {
+        assertThrows(IllegalArgumentException.class, () -> JacobsthalNumber.jacobsthal(-1));
+    }
+}

From 8a3bd3aa02611255bf26793f4d158ea54a13fab5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 18 Jun 2026 19:33:41 +0200
Subject: [PATCH 1278/1338] chore(deps): bump actions/checkout from 6 to 7 in
 /.github/workflows (#7483)

Bumps [actions/checkout](https://github.com/actions/checkout) from 6 to 7.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v6...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml              | 2 +-
 .github/workflows/clang-format-lint.yml  | 2 +-
 .github/workflows/codeql.yml             | 4 ++--
 .github/workflows/infer.yml              | 2 +-
 .github/workflows/project_structure.yml  | 2 +-
 .github/workflows/update-directorymd.yml | 4 ++--
 6 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 4b1f0f376e25..b8f4c8efa7e6 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -8,7 +8,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - name: Set up JDK
         uses: actions/setup-java@v5
         with:
diff --git a/.github/workflows/clang-format-lint.yml b/.github/workflows/clang-format-lint.yml
index dc0c9754ed1b..622679f73842 100644
--- a/.github/workflows/clang-format-lint.yml
+++ b/.github/workflows/clang-format-lint.yml
@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - uses: DoozyX/clang-format-lint-action@v0.20
       with:
         source: './src'
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 152d0d766fd2..14ea223946cd 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -21,7 +21,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Set up JDK
         uses: actions/setup-java@v5
@@ -52,7 +52,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v4
diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index fbc0f1f1bc7f..6bf5c56a91b1 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -15,7 +15,7 @@ jobs:
   run_infer:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Set up JDK
         uses: actions/setup-java@v5
diff --git a/.github/workflows/project_structure.yml b/.github/workflows/project_structure.yml
index 5aadc6353791..e7e703c27b70 100644
--- a/.github/workflows/project_structure.yml
+++ b/.github/workflows/project_structure.yml
@@ -15,7 +15,7 @@ jobs:
   check_structure:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - uses: actions/setup-python@v6
         with:
           python-version: '3.13'
diff --git a/.github/workflows/update-directorymd.yml b/.github/workflows/update-directorymd.yml
index 1cfee6e36e4e..3977bfda86bf 100644
--- a/.github/workflows/update-directorymd.yml
+++ b/.github/workflows/update-directorymd.yml
@@ -1,4 +1,4 @@
-name: Generate Directory Markdown
+name: Generate Directory Markdown
 
 on:
   push:
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
         with:
           persist-credentials: false
 

From fafc5a2964d351b691d05df41994f4e05257cdeb Mon Sep 17 00:00:00 2001
From: Priyanshu <pv254424@gmail.com>
Date: Sun, 21 Jun 2026 01:21:46 +0530
Subject: [PATCH 1279/1338] chore: move HeavyLightDecomposition to
 datastructures/trees (#7485)

---
 .../{tree => datastructures/trees}/HeavyLightDecomposition.java | 2 +-
 .../trees}/HeavyLightDecompositionTest.java                     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
 rename src/main/java/com/thealgorithms/{tree => datastructures/trees}/HeavyLightDecomposition.java (99%)
 rename src/test/java/com/thealgorithms/{tree => datastructures/trees}/HeavyLightDecompositionTest.java (97%)

diff --git a/src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java b/src/main/java/com/thealgorithms/datastructures/trees/HeavyLightDecomposition.java
similarity index 99%
rename from src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java
rename to src/main/java/com/thealgorithms/datastructures/trees/HeavyLightDecomposition.java
index 236a23205180..ed67f9ae3394 100644
--- a/src/main/java/com/thealgorithms/tree/HeavyLightDecomposition.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/HeavyLightDecomposition.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.tree;
+package com.thealgorithms.datastructures.trees;
 
 import java.util.ArrayList;
 import java.util.List;
diff --git a/src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java b/src/test/java/com/thealgorithms/datastructures/trees/HeavyLightDecompositionTest.java
similarity index 97%
rename from src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java
rename to src/test/java/com/thealgorithms/datastructures/trees/HeavyLightDecompositionTest.java
index 29189290e1d4..f0cb1724f67c 100644
--- a/src/test/java/com/thealgorithms/tree/HeavyLightDecompositionTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/trees/HeavyLightDecompositionTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.tree;
+package com.thealgorithms.datastructures.trees;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;

From e57a675893fb6a8fbc725085a3b3039b7565a0b1 Mon Sep 17 00:00:00 2001
From: Priyanshu <pv254424@gmail.com>
Date: Sun, 21 Jun 2026 01:26:26 +0530
Subject: [PATCH 1280/1338] Fix division by zero in interpolation search
 (#7484)

* Fix division by zero in interpolation search

* style: fix formatting in InterpolationSearchTest
---
 .../thealgorithms/searches/InterpolationSearch.java   |  5 ++++-
 .../searches/InterpolationSearchTest.java             | 11 +++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/InterpolationSearch.java b/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
index 272627fc48b4..52dbc0b7e2c5 100644
--- a/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
+++ b/src/main/java/com/thealgorithms/searches/InterpolationSearch.java
@@ -36,9 +36,12 @@ public int find(int[] array, int key) {
         // Since array is sorted, an element present
         // in array must be in range defined by corner
         while (start <= end && key >= array[start] && key <= array[end]) {
+            if (array[start] == array[end]) {
+                return start;
+            }
             // Probing the position with keeping
             // uniform distribution in mind.
-            int pos = start + (((end - start) / (array[end] - array[start])) * (key - array[start]));
+            int pos = start + (int) (((long) (end - start) * (key - array[start])) / ((long) array[end] - array[start]));
 
             // Condition of target found
             if (array[pos] == key) {
diff --git a/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java b/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java
index b3b7e7ef129c..b7ef64125da8 100644
--- a/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java
@@ -87,4 +87,15 @@ void testInterpolationSearchLargeNonUniformArray() {
         int key = 21; // Present in the array
         assertEquals(6, interpolationSearch.find(array, key), "The index of the found element should be 6.");
     }
+
+    /**
+     * Test for interpolation search with specific sorted arrays that previously caused division by zero.
+     */
+    @Test
+    void testInterpolationSearchDivisionByZeroEdgeCases() {
+        InterpolationSearch interpolationSearch = new InterpolationSearch();
+        assertEquals(3, interpolationSearch.find(new int[] {0, 0, 0, 2}, 2));
+        assertEquals(0, interpolationSearch.find(new int[] {2, 2, 2, 2}, 2));
+        assertEquals(3, interpolationSearch.find(new int[] {0, 1, 2, 4}, 4));
+    }
 }

From 631eae3f1352f6ccfa6e9d7b76a420cc31e49e6a Mon Sep 17 00:00:00 2001
From: Rosander0 <astereen.0107@gmail.com>
Date: Sun, 21 Jun 2026 03:53:29 +0530
Subject: [PATCH 1281/1338] Add PadovanSequence Implementation (#7477)

feat: Add PadovanSequence Implementation
---
 .../thealgorithms/maths/PadovanSequence.java  | 43 +++++++++++++++++++
 .../maths/PadovanSequenceTest.java            | 36 ++++++++++++++++
 2 files changed, 79 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/PadovanSequence.java
 create mode 100644 src/test/java/com/thealgorithms/maths/PadovanSequenceTest.java

diff --git a/src/main/java/com/thealgorithms/maths/PadovanSequence.java b/src/main/java/com/thealgorithms/maths/PadovanSequence.java
new file mode 100644
index 000000000000..51e7d2441b15
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/PadovanSequence.java
@@ -0,0 +1,43 @@
+package com.thealgorithms.maths;
+
+/**
+ * The Padovan Sequence is a sequence of integers defined by the recurrence relation:
+ * P(n) = P(n-2) + P(n-3) with initial values P(0) = P(1) = P(2) = 1.
+ * Example: 1, 1, 1, 2, 2, 3, 4, 5, 7, 9, 12, 16, 21, 28, 37...
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Padovan_sequence">
+ *     Wikipedia: Padovan Sequence</a>
+ * @author Vraj Prajapati (@Rosander0)
+ */
+public final class PadovanSequence {
+
+    private PadovanSequence() {
+        // Utility class
+    }
+
+    /**
+     * Calculates the nth term of the Padovan Sequence.
+     *
+     * @param n the index of the sequence (must be non-negative)
+     * @return the nth term of the Padovan Sequence
+     */
+    public static long padovan(final int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input must be non-negative. Received: " + n);
+        }
+        if (n <= 2) {
+            return 1;
+        }
+        long a = 1;
+        long b = 1;
+        long c = 1;
+        long result = 0;
+        for (int i = 3; i <= n; i++) {
+            result = a + b;
+            a = b;
+            b = c;
+            c = result;
+        }
+        return result;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/PadovanSequenceTest.java b/src/test/java/com/thealgorithms/maths/PadovanSequenceTest.java
new file mode 100644
index 000000000000..b9d7f04b4d0b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/PadovanSequenceTest.java
@@ -0,0 +1,36 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author Vraj Prajapati (@Rosander0)
+ */
+public class PadovanSequenceTest {
+
+    @Test
+    public void testBaseCase() {
+        assertEquals(1, PadovanSequence.padovan(0));
+        assertEquals(1, PadovanSequence.padovan(1));
+        assertEquals(1, PadovanSequence.padovan(2));
+    }
+
+    @Test
+    public void testKnownValues() {
+        assertEquals(2, PadovanSequence.padovan(3));
+        assertEquals(2, PadovanSequence.padovan(4));
+        assertEquals(3, PadovanSequence.padovan(5));
+        assertEquals(4, PadovanSequence.padovan(6));
+        assertEquals(5, PadovanSequence.padovan(7));
+        assertEquals(7, PadovanSequence.padovan(8));
+        assertEquals(9, PadovanSequence.padovan(9));
+        assertEquals(12, PadovanSequence.padovan(10));
+    }
+
+    @Test
+    public void testInvalidInput() {
+        assertThrows(IllegalArgumentException.class, () -> PadovanSequence.padovan(-1));
+    }
+}

From a508fd2647c439d1986c3f914386d600632cc3bd Mon Sep 17 00:00:00 2001
From: Rosander0 <astereen.0107@gmail.com>
Date: Mon, 22 Jun 2026 12:54:40 +0530
Subject: [PATCH 1282/1338] Add FriendlyNumber Implementation (#7474)

feat: Add FriendlyNumber Implementation
---
 .../thealgorithms/maths/FriendlyNumber.java   | 49 +++++++++++++++++++
 .../maths/FriendlyNumberTest.java             | 33 +++++++++++++
 2 files changed, 82 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/FriendlyNumber.java
 create mode 100644 src/test/java/com/thealgorithms/maths/FriendlyNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/FriendlyNumber.java b/src/main/java/com/thealgorithms/maths/FriendlyNumber.java
new file mode 100644
index 000000000000..900ce89295a4
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/FriendlyNumber.java
@@ -0,0 +1,49 @@
+package com.thealgorithms.maths;
+
+/**
+ * Two numbers are Friendly if they share the same abundancy index,
+ * which is the ratio of the sum of divisors to the number itself.
+ * Example: 6 and 28 are friendly because sigma(6)/6 = 2 and sigma(28)/28 = 2
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Friendly_number">
+ *     Wikipedia: Friendly Number</a>
+ *
+ * @author Vraj Prajapati @Rosander0
+ */
+public final class FriendlyNumber {
+
+    private FriendlyNumber() {
+        // Utility class
+    }
+
+    private static int sumOfDivisors(final int number) {
+        int sum = 0;
+        final int root = (int) Math.sqrt(number);
+        for (int i = 1; i <= root; i++) {
+            if (number % i == 0) {
+                sum += i;
+                final int other = number / i;
+                if (other != i) {
+                    sum += other;
+                }
+            }
+        }
+        return sum;
+    }
+
+    /**
+     * Checks whether two numbers are Friendly Numbers.
+     *
+     * @param a First number (must be positive)
+     * @param b Second number (must be positive)
+     * @return true if a and b are friendly numbers, false otherwise
+     */
+    public static boolean areFriendly(final int a, final int b) {
+        if (a <= 0 || b <= 0) {
+            return false;
+        }
+        final long sigmaA = sumOfDivisors(a);
+        final long sigmaB = sumOfDivisors(b);
+        return sigmaA * b == sigmaB * a;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/FriendlyNumberTest.java b/src/test/java/com/thealgorithms/maths/FriendlyNumberTest.java
new file mode 100644
index 000000000000..be5ddd7ee79e
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/FriendlyNumberTest.java
@@ -0,0 +1,33 @@
+package com.thealgorithms.maths;
+// author: Vraj Prajapati @Rosander0
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class FriendlyNumberTest {
+
+    @Test
+    public void testFriendlyNumbers() {
+        // 6 and 28 are friendly (abundancy index = 2)
+        assertTrue(FriendlyNumber.areFriendly(6, 28));
+        // Every number is friendly with itself
+        assertTrue(FriendlyNumber.areFriendly(6, 6));
+        assertTrue(FriendlyNumber.areFriendly(1, 1));
+    }
+
+    @Test
+    public void testNonFriendlyNumbers() {
+        assertFalse(FriendlyNumber.areFriendly(6, 10));
+        assertFalse(FriendlyNumber.areFriendly(10, 15));
+        assertFalse(FriendlyNumber.areFriendly(4, 9));
+    }
+
+    @Test
+    public void testInvalidInputs() {
+        assertFalse(FriendlyNumber.areFriendly(0, 6));
+        assertFalse(FriendlyNumber.areFriendly(-1, 6));
+        assertFalse(FriendlyNumber.areFriendly(6, -1));
+    }
+}

From 0fe06acce7c8f519b66c34061229ac0d49c16fa7 Mon Sep 17 00:00:00 2001
From: Priyanshu <pv254424@gmail.com>
Date: Mon, 22 Jun 2026 21:48:10 +0530
Subject: [PATCH 1283/1338] fix: validate that all  characters after first
 padding character in Base64 decode (#7491)

fix: validate that all characters after first padding character are also padding characters
---
 .../java/com/thealgorithms/conversions/Base64.java    | 11 +++++++++--
 .../com/thealgorithms/conversions/Base64Test.java     |  3 +++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/conversions/Base64.java b/src/main/java/com/thealgorithms/conversions/Base64.java
index 5219c4ba7f4e..fb4411b399a3 100644
--- a/src/main/java/com/thealgorithms/conversions/Base64.java
+++ b/src/main/java/com/thealgorithms/conversions/Base64.java
@@ -119,8 +119,15 @@ public static byte[] decode(String input) {
 
         // Validate padding: '=' can only appear at the end (last 1 or 2 chars)
         int firstPadding = input.indexOf('=');
-        if (firstPadding != -1 && firstPadding < input.length() - 2) {
-            throw new IllegalArgumentException("Padding '=' can only appear at the end (last 1 or 2 characters)");
+        if (firstPadding != -1) {
+            if (firstPadding < input.length() - 2) {
+                throw new IllegalArgumentException("Padding '=' can only appear at the end (last 1 or 2 characters)");
+            }
+            for (int i = firstPadding; i < input.length(); i++) {
+                if (input.charAt(i) != '=') {
+                    throw new IllegalArgumentException("A padding '=' must not be followed by a non-padding character");
+                }
+            }
         }
 
         List<Byte> result = new ArrayList<>();
diff --git a/src/test/java/com/thealgorithms/conversions/Base64Test.java b/src/test/java/com/thealgorithms/conversions/Base64Test.java
index fbc220c0ca95..cd0d6c8b38a8 100644
--- a/src/test/java/com/thealgorithms/conversions/Base64Test.java
+++ b/src/test/java/com/thealgorithms/conversions/Base64Test.java
@@ -127,6 +127,9 @@ void testInvalidPaddingPosition() {
         assertThrows(IllegalArgumentException.class, () -> Base64.decode("Q=QQ"));
         assertThrows(IllegalArgumentException.class, () -> Base64.decode("Q=Q="));
         assertThrows(IllegalArgumentException.class, () -> Base64.decode("=QQQ"));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("QQ=Q"));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("AB=C"));
+        assertThrows(IllegalArgumentException.class, () -> Base64.decode("AB=A"));
     }
 
     @Test

From 00339c759c4a05800cd577613d737b019e2131b7 Mon Sep 17 00:00:00 2001
From: Priyanshu <pv254424@gmail.com>
Date: Tue, 23 Jun 2026 15:24:14 +0530
Subject: [PATCH 1284/1338] refactor: unify Dijkstra on efficient PriorityQueue
 implementation (#7486)

---
 .../graphs/DijkstraAlgorithm.java             | 50 +++++++-------
 .../graphs/DijkstraOptimizedAlgorithm.java    | 66 -------------------
 .../DijkstraOptimizedAlgorithmTest.java       | 64 ------------------
 3 files changed, 26 insertions(+), 154 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java
 delete mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java
index 70699a9461f7..1b5f765843be 100644
--- a/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraAlgorithm.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.graphs;
 
 import java.util.Arrays;
+import java.util.PriorityQueue;
 
 /**
  * Dijkstra's algorithm for finding the shortest path from a single source vertex to all other vertices in a graph.
@@ -18,6 +19,21 @@ public DijkstraAlgorithm(int vertexCount) {
         this.vertexCount = vertexCount;
     }
 
+    private static class Node implements Comparable<Node> {
+        int id;
+        int distance;
+
+        Node(int id, int distance) {
+            this.id = id;
+            this.distance = distance;
+        }
+
+        @Override
+        public int compareTo(Node other) {
+            return Integer.compare(this.distance, other.distance);
+        }
+    }
+
     /**
      * Executes Dijkstra's algorithm on the provided graph to find the shortest paths from the source vertex to all other vertices.
      *
@@ -36,18 +52,25 @@ public int[] run(int[][] graph, int source) {
 
         int[] distances = new int[vertexCount];
         boolean[] processed = new boolean[vertexCount];
+        PriorityQueue<Node> unprocessed = new PriorityQueue<>();
 
         Arrays.fill(distances, Integer.MAX_VALUE);
-        Arrays.fill(processed, false);
         distances[source] = 0;
+        unprocessed.add(new Node(source, 0));
+
+        while (!unprocessed.isEmpty()) {
+            Node current = unprocessed.poll();
+            int u = current.id;
 
-        for (int count = 0; count < vertexCount - 1; count++) {
-            int u = getMinDistanceVertex(distances, processed);
+            if (processed[u]) {
+                continue;
+            }
             processed[u] = true;
 
             for (int v = 0; v < vertexCount; v++) {
                 if (!processed[v] && graph[u][v] != 0 && distances[u] != Integer.MAX_VALUE && distances[u] + graph[u][v] < distances[v]) {
                     distances[v] = distances[u] + graph[u][v];
+                    unprocessed.add(new Node(v, distances[v]));
                 }
             }
         }
@@ -56,27 +79,6 @@ public int[] run(int[][] graph, int source) {
         return distances;
     }
 
-    /**
-     * Finds the vertex with the minimum distance value from the set of vertices that have not yet been processed.
-     *
-     * @param distances The array of current shortest distances from the source vertex.
-     * @param processed The array indicating whether each vertex has been processed.
-     * @return The index of the vertex with the minimum distance value.
-     */
-    private int getMinDistanceVertex(int[] distances, boolean[] processed) {
-        int min = Integer.MAX_VALUE;
-        int minIndex = -1;
-
-        for (int v = 0; v < vertexCount; v++) {
-            if (!processed[v] && distances[v] <= min) {
-                min = distances[v];
-                minIndex = v;
-            }
-        }
-
-        return minIndex;
-    }
-
     /**
      * Prints the shortest distances from the source vertex to all other vertices.
      *
diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java b/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java
deleted file mode 100644
index a686b808a970..000000000000
--- a/src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java
+++ /dev/null
@@ -1,66 +0,0 @@
-package com.thealgorithms.datastructures.graphs;
-
-import java.util.Arrays;
-import java.util.Set;
-import java.util.TreeSet;
-import org.apache.commons.lang3.tuple.Pair;
-
-/**
- * Dijkstra's algorithm for finding the shortest path from a single source vertex to all other vertices in a graph.
- */
-public class DijkstraOptimizedAlgorithm {
-
-    private final int vertexCount;
-
-    /**
-     * Constructs a Dijkstra object with the given number of vertices.
-     *
-     * @param vertexCount The number of vertices in the graph.
-     */
-    public DijkstraOptimizedAlgorithm(int vertexCount) {
-        this.vertexCount = vertexCount;
-    }
-
-    /**
-     * Executes Dijkstra's algorithm on the provided graph to find the shortest paths from the source vertex to all other vertices.
-     *
-     * The graph is represented as an adjacency matrix where {@code graph[i][j]} represents the weight of the edge from vertex {@code i}
-     * to vertex {@code j}. A value of 0 indicates no edge exists between the vertices.
-     *
-     * @param graph The graph represented as an adjacency matrix.
-     * @param source The source vertex.
-     * @return An array where the value at each index {@code i} represents the shortest distance from the source vertex to vertex {@code i}.
-     * @throws IllegalArgumentException if the source vertex is out of range.
-     */
-    public int[] run(int[][] graph, int source) {
-        if (source < 0 || source >= vertexCount) {
-            throw new IllegalArgumentException("Incorrect source");
-        }
-
-        int[] distances = new int[vertexCount];
-        boolean[] processed = new boolean[vertexCount];
-        Set<Pair<Integer, Integer>> unprocessed = new TreeSet<>();
-
-        Arrays.fill(distances, Integer.MAX_VALUE);
-        Arrays.fill(processed, false);
-        distances[source] = 0;
-        unprocessed.add(Pair.of(0, source));
-
-        while (!unprocessed.isEmpty()) {
-            Pair<Integer, Integer> distanceAndU = unprocessed.iterator().next();
-            unprocessed.remove(distanceAndU);
-            int u = distanceAndU.getRight();
-            processed[u] = true;
-
-            for (int v = 0; v < vertexCount; v++) {
-                if (!processed[v] && graph[u][v] != 0 && distances[u] != Integer.MAX_VALUE && distances[u] + graph[u][v] < distances[v]) {
-                    unprocessed.remove(Pair.of(distances[v], v));
-                    distances[v] = distances[u] + graph[u][v];
-                    unprocessed.add(Pair.of(distances[v], v));
-                }
-            }
-        }
-
-        return distances;
-    }
-}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java
deleted file mode 100644
index bf4e2828e069..000000000000
--- a/src/test/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithmTest.java
+++ /dev/null
@@ -1,64 +0,0 @@
-package com.thealgorithms.datastructures.graphs;
-
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-
-public class DijkstraOptimizedAlgorithmTest {
-
-    private DijkstraOptimizedAlgorithm dijkstraOptimizedAlgorithm;
-    private int[][] graph;
-
-    @BeforeEach
-    void setUp() {
-        graph = new int[][] {
-            {0, 4, 0, 0, 0, 0, 0, 8, 0},
-            {4, 0, 8, 0, 0, 0, 0, 11, 0},
-            {0, 8, 0, 7, 0, 4, 0, 0, 2},
-            {0, 0, 7, 0, 9, 14, 0, 0, 0},
-            {0, 0, 0, 9, 0, 10, 0, 0, 0},
-            {0, 0, 4, 14, 10, 0, 2, 0, 0},
-            {0, 0, 0, 0, 0, 2, 0, 1, 6},
-            {8, 11, 0, 0, 0, 0, 1, 0, 7},
-            {0, 0, 2, 0, 0, 0, 6, 7, 0},
-        };
-
-        dijkstraOptimizedAlgorithm = new DijkstraOptimizedAlgorithm(graph.length);
-    }
-
-    @Test
-    void testRunAlgorithm() {
-        int[] expectedDistances = {0, 4, 12, 19, 21, 11, 9, 8, 14};
-        assertArrayEquals(expectedDistances, dijkstraOptimizedAlgorithm.run(graph, 0));
-    }
-
-    @Test
-    void testGraphWithDisconnectedNodes() {
-        int[][] disconnectedGraph = {
-            {0, 3, 0, 0}, {3, 0, 1, 0}, {0, 1, 0, 0}, {0, 0, 0, 0} // Node 3 is disconnected
-        };
-
-        DijkstraOptimizedAlgorithm dijkstraDisconnected = new DijkstraOptimizedAlgorithm(disconnectedGraph.length);
-
-        // Testing from vertex 0
-        int[] expectedDistances = {0, 3, 4, Integer.MAX_VALUE}; // Node 3 is unreachable
-        assertArrayEquals(expectedDistances, dijkstraDisconnected.run(disconnectedGraph, 0));
-    }
-
-    @Test
-    void testSingleVertexGraph() {
-        int[][] singleVertexGraph = {{0}};
-        DijkstraOptimizedAlgorithm dijkstraSingleVertex = new DijkstraOptimizedAlgorithm(1);
-
-        int[] expectedDistances = {0}; // The only vertex's distance to itself is 0
-        assertArrayEquals(expectedDistances, dijkstraSingleVertex.run(singleVertexGraph, 0));
-    }
-
-    @Test
-    void testInvalidSourceVertex() {
-        assertThrows(IllegalArgumentException.class, () -> dijkstraOptimizedAlgorithm.run(graph, -1));
-        assertThrows(IllegalArgumentException.class, () -> dijkstraOptimizedAlgorithm.run(graph, graph.length));
-    }
-}

From 0e001b7dbadf1ea06056e7cbdfb2b943ec6452cd Mon Sep 17 00:00:00 2001
From: Rosander0 <astereen.0107@gmail.com>
Date: Wed, 24 Jun 2026 03:30:03 +0530
Subject: [PATCH 1285/1338] Add SociableNumber Implementation (#7475)

feat: add SociableNumber implementation
---
 .../thealgorithms/maths/SociableNumber.java   | 67 +++++++++++++++++++
 .../maths/SociableNumberTest.java             | 56 ++++++++++++++++
 2 files changed, 123 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/SociableNumber.java
 create mode 100644 src/test/java/com/thealgorithms/maths/SociableNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/SociableNumber.java b/src/main/java/com/thealgorithms/maths/SociableNumber.java
new file mode 100644
index 000000000000..9ce644e61dfc
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/SociableNumber.java
@@ -0,0 +1,67 @@
+package com.thealgorithms.maths;
+
+/**
+ * Sociable numbers are natural numbers that form a cyclic sequence where the
+ * sum of proper divisors of each number equals the next number in the sequence,
+ * with the sequence eventually returning to the starting number.
+ * Amicable numbers are a special case of sociable numbers with a cycle length of 2.
+ * Example: (12496, 14288, 15472, 14536, 14264) is a sociable cycle of length 5.
+ *
+ * @author Vraj Prajapati (@Rosander0)
+ * @see <a href="https://en.wikipedia.org/wiki/Sociable_number">Wikipedia: Sociable Number</a>
+ * @see AmicableNumber
+ */
+public final class SociableNumber {
+
+    private SociableNumber() {
+        // Utility class
+    }
+
+    /**
+     * Calculates the sum of proper divisors of a number
+     * (all divisors excluding the number itself).
+     *
+     * @param number the number to calculate proper divisors sum for
+     * @return sum of proper divisors, or 0 if number is less than or equal to 1
+     */
+    static int sumOfProperDivisors(final int number) {
+        if (number <= 1) {
+            return 0;
+        }
+        int sum = 1; // 1 is a proper divisor of every number > 1
+        final int root = (int) Math.sqrt(number);
+        for (int i = 2; i <= root; i++) {
+            if (number % i == 0) {
+                final int other = number / i;
+                sum += i;
+                if (other != i) {
+                    sum += other;
+                }
+            }
+        }
+        return sum;
+    }
+
+    /**
+     * Checks whether a number is part of a sociable cycle of a given length.
+     * Starting from the given number, it follows the chain of proper divisor
+     * sums and checks if it returns to the starting number in exactly cycleLength steps.
+     *
+     * @param number the starting number (must be positive)
+     * @param cycleLength the expected cycle length (must be greater than 1)
+     * @return true if the number is part of a sociable cycle of given length, false otherwise
+     */
+    public static boolean isSociable(final int number, final int cycleLength) {
+        if (number <= 0 || cycleLength <= 1) {
+            return false;
+        }
+        int current = number;
+        for (int i = 0; i < cycleLength; i++) {
+            current = sumOfProperDivisors(current);
+            if (current == number) {
+                return i == cycleLength - 1;
+            }
+        }
+        return false;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/SociableNumberTest.java b/src/test/java/com/thealgorithms/maths/SociableNumberTest.java
new file mode 100644
index 000000000000..b4877cd761a7
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/SociableNumberTest.java
@@ -0,0 +1,56 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests for {@link SociableNumber}.
+ *
+ * @author Vraj Prajapati (@Rosander0)
+ */
+public class SociableNumberTest {
+
+    @Test
+    public void testSumOfProperDivisorsEdgeCases() {
+        assertEquals(0, SociableNumber.sumOfProperDivisors(0));
+        assertEquals(0, SociableNumber.sumOfProperDivisors(-5));
+        assertEquals(0, SociableNumber.sumOfProperDivisors(1));
+        assertEquals(1, SociableNumber.sumOfProperDivisors(2));
+    }
+
+    @Test
+    public void testSociableCycleOfLengthFive() {
+        assertTrue(SociableNumber.isSociable(12496, 5));
+    }
+
+    @Test
+    public void testAmicableNumbersAreSociableOfLengthTwo() {
+        assertTrue(SociableNumber.isSociable(220, 2));
+        assertTrue(SociableNumber.isSociable(284, 2));
+    }
+
+    @Test
+    public void testNonSociableNumbers() {
+        assertFalse(SociableNumber.isSociable(12, 5));
+        assertFalse(SociableNumber.isSociable(10, 3));
+    }
+
+    @Test
+    public void testEarlyCycleReturn() {
+        // 220 has cycle length 2; requesting a different length should return
+        // false because it returns to the start too early.
+        assertFalse(SociableNumber.isSociable(220, 3));
+        assertFalse(SociableNumber.isSociable(284, 4));
+        assertFalse(SociableNumber.isSociable(12496, 3));
+    }
+
+    @Test
+    public void testInvalidInputs() {
+        assertFalse(SociableNumber.isSociable(0, 5));
+        assertFalse(SociableNumber.isSociable(-1, 5));
+        assertFalse(SociableNumber.isSociable(220, 1));
+    }
+}

From 51137a14ffa10dc24edbfe14ea94d1e1c397caa5 Mon Sep 17 00:00:00 2001
From: Priyanshu <pv254424@gmail.com>
Date: Wed, 24 Jun 2026 22:36:54 +0530
Subject: [PATCH 1286/1338] refactor: review and group scattered palindrome
 implementation (#7487)

* feat: add utility to find lowest base for palindromic numbers and implement palindrome check for singly linked lists

* feat: add palindrome check for linked lists and find lowest base palindrome implementation

* feat: add utility to check if an integer's binary representation is a palindrome

* feat: add algorithm to check if a singly linked list is a palindrome

* feat: add PalindromeNumber utility class to check for palindromic integers

* style: remove redundant import to fix checkstyle error

* style: add blank line between static and non-static imports
---
 .../bitmanipulation/BinaryPalindromeCheck.java      |  6 ++++++
 .../lists}/PalindromeSinglyLinkedList.java          |  9 ++++++++-
 .../{others => maths}/LowestBasePalindrome.java     |  8 +++++++-
 .../com/thealgorithms/maths/PalindromeNumber.java   | 11 +++++++++++
 .../{misc => maths}/PalindromePrime.java            | 13 ++++++++++++-
 .../thealgorithms/stacks/PalindromeWithStack.java   |  7 +++++++
 .../java/com/thealgorithms/strings/Palindrome.java  |  7 +++++++
 .../lists}/PalindromeSinglyLinkedListTest.java      |  3 +--
 .../{others => maths}/LowestBasePalindromeTest.java |  2 +-
 .../{misc => maths}/PalindromePrimeTest.java        |  2 +-
 10 files changed, 61 insertions(+), 7 deletions(-)
 rename src/main/java/com/thealgorithms/{misc => datastructures/lists}/PalindromeSinglyLinkedList.java (84%)
 rename src/main/java/com/thealgorithms/{others => maths}/LowestBasePalindrome.java (94%)
 rename src/main/java/com/thealgorithms/{misc => maths}/PalindromePrime.java (73%)
 rename src/test/java/com/thealgorithms/{misc => datastructures/lists}/PalindromeSinglyLinkedListTest.java (98%)
 rename src/test/java/com/thealgorithms/{others => maths}/LowestBasePalindromeTest.java (99%)
 rename src/test/java/com/thealgorithms/{misc => maths}/PalindromePrimeTest.java (98%)

diff --git a/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java b/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java
index 0d6fd140c720..5038d44079ec 100644
--- a/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java
+++ b/src/main/java/com/thealgorithms/bitmanipulation/BinaryPalindromeCheck.java
@@ -9,6 +9,12 @@
  * </p>
  *
  * @author Hardvan
+ * @see com.thealgorithms.strings.Palindrome
+ * @see com.thealgorithms.stacks.PalindromeWithStack
+ * @see com.thealgorithms.maths.LowestBasePalindrome
+ * @see com.thealgorithms.datastructures.lists.PalindromeSinglyLinkedList
+ * @see com.thealgorithms.maths.PalindromePrime
+ * @see com.thealgorithms.maths.PalindromeNumber
  */
 public final class BinaryPalindromeCheck {
     private BinaryPalindromeCheck() {
diff --git a/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/PalindromeSinglyLinkedList.java
similarity index 84%
rename from src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
rename to src/main/java/com/thealgorithms/datastructures/lists/PalindromeSinglyLinkedList.java
index c81476eaec32..7bb16921b9ef 100644
--- a/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/PalindromeSinglyLinkedList.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.datastructures.lists;
 
 import java.util.Stack;
 
@@ -9,6 +9,13 @@
  *
  * See more:
  * https://www.geeksforgeeks.org/function-to-check-if-a-singly-linked-list-is-palindrome/
+ *
+ * @see com.thealgorithms.strings.Palindrome
+ * @see com.thealgorithms.stacks.PalindromeWithStack
+ * @see com.thealgorithms.bitmanipulation.BinaryPalindromeCheck
+ * @see com.thealgorithms.maths.LowestBasePalindrome
+ * @see com.thealgorithms.maths.PalindromePrime
+ * @see com.thealgorithms.maths.PalindromeNumber
  */
 @SuppressWarnings("rawtypes")
 public final class PalindromeSinglyLinkedList {
diff --git a/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java b/src/main/java/com/thealgorithms/maths/LowestBasePalindrome.java
similarity index 94%
rename from src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
rename to src/main/java/com/thealgorithms/maths/LowestBasePalindrome.java
index a3ca8d6f6db8..4a79b4298fc4 100644
--- a/src/main/java/com/thealgorithms/others/LowestBasePalindrome.java
+++ b/src/main/java/com/thealgorithms/maths/LowestBasePalindrome.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.maths;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -23,6 +23,12 @@
  *
  * @see <a href="https://oeis.org/A016026">OEIS A016026 - Smallest base in which
  *      n is palindromic</a>
+ * @see com.thealgorithms.strings.Palindrome
+ * @see com.thealgorithms.stacks.PalindromeWithStack
+ * @see com.thealgorithms.bitmanipulation.BinaryPalindromeCheck
+ * @see com.thealgorithms.datastructures.lists.PalindromeSinglyLinkedList
+ * @see com.thealgorithms.maths.PalindromePrime
+ * @see com.thealgorithms.maths.PalindromeNumber
  * @author TheAlgorithms Contributors
  */
 public final class LowestBasePalindrome {
diff --git a/src/main/java/com/thealgorithms/maths/PalindromeNumber.java b/src/main/java/com/thealgorithms/maths/PalindromeNumber.java
index a22d63897b37..9543f83332a7 100644
--- a/src/main/java/com/thealgorithms/maths/PalindromeNumber.java
+++ b/src/main/java/com/thealgorithms/maths/PalindromeNumber.java
@@ -1,5 +1,16 @@
 package com.thealgorithms.maths;
 
+/**
+ * A class to check if a given number is a palindrome.
+ * A palindromic number is a number that remains the same when its digits are reversed.
+ *
+ * @see com.thealgorithms.strings.Palindrome
+ * @see com.thealgorithms.stacks.PalindromeWithStack
+ * @see com.thealgorithms.bitmanipulation.BinaryPalindromeCheck
+ * @see com.thealgorithms.maths.LowestBasePalindrome
+ * @see com.thealgorithms.datastructures.lists.PalindromeSinglyLinkedList
+ * @see com.thealgorithms.maths.PalindromePrime
+ */
 public final class PalindromeNumber {
     private PalindromeNumber() {
     }
diff --git a/src/main/java/com/thealgorithms/misc/PalindromePrime.java b/src/main/java/com/thealgorithms/maths/PalindromePrime.java
similarity index 73%
rename from src/main/java/com/thealgorithms/misc/PalindromePrime.java
rename to src/main/java/com/thealgorithms/maths/PalindromePrime.java
index 164e957a9d12..21b76acefee8 100644
--- a/src/main/java/com/thealgorithms/misc/PalindromePrime.java
+++ b/src/main/java/com/thealgorithms/maths/PalindromePrime.java
@@ -1,8 +1,19 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.maths;
 
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * A class to check and generate palindromic prime numbers.
+ * A palindromic prime is a prime number that is also a palindromic number.
+ *
+ * @see com.thealgorithms.strings.Palindrome
+ * @see com.thealgorithms.stacks.PalindromeWithStack
+ * @see com.thealgorithms.bitmanipulation.BinaryPalindromeCheck
+ * @see com.thealgorithms.maths.LowestBasePalindrome
+ * @see com.thealgorithms.datastructures.lists.PalindromeSinglyLinkedList
+ * @see com.thealgorithms.maths.PalindromeNumber
+ */
 public final class PalindromePrime {
     private PalindromePrime() {
     }
diff --git a/src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java b/src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java
index 98c439341a21..7afe2c99aae8 100644
--- a/src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java
+++ b/src/main/java/com/thealgorithms/stacks/PalindromeWithStack.java
@@ -8,6 +8,13 @@
  * which we will pop one-by-one to create the string in reverse.
  *
  * Reference: https://www.geeksforgeeks.org/check-whether-the-given-string-is-palindrome-using-stack/
+ *
+ * @see com.thealgorithms.strings.Palindrome
+ * @see com.thealgorithms.bitmanipulation.BinaryPalindromeCheck
+ * @see com.thealgorithms.maths.LowestBasePalindrome
+ * @see com.thealgorithms.datastructures.lists.PalindromeSinglyLinkedList
+ * @see com.thealgorithms.maths.PalindromePrime
+ * @see com.thealgorithms.maths.PalindromeNumber
  */
 public class PalindromeWithStack {
     private LinkedList<Character> stack;
diff --git a/src/main/java/com/thealgorithms/strings/Palindrome.java b/src/main/java/com/thealgorithms/strings/Palindrome.java
index 3567a371d70e..64de657df359 100644
--- a/src/main/java/com/thealgorithms/strings/Palindrome.java
+++ b/src/main/java/com/thealgorithms/strings/Palindrome.java
@@ -2,6 +2,13 @@
 
 /**
  * Wikipedia: https://en.wikipedia.org/wiki/Palindrome
+ *
+ * @see com.thealgorithms.stacks.PalindromeWithStack
+ * @see com.thealgorithms.bitmanipulation.BinaryPalindromeCheck
+ * @see com.thealgorithms.maths.LowestBasePalindrome
+ * @see com.thealgorithms.datastructures.lists.PalindromeSinglyLinkedList
+ * @see com.thealgorithms.maths.PalindromePrime
+ * @see com.thealgorithms.maths.PalindromeNumber
  */
 final class Palindrome {
     private Palindrome() {
diff --git a/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/PalindromeSinglyLinkedListTest.java
similarity index 98%
rename from src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java
rename to src/test/java/com/thealgorithms/datastructures/lists/PalindromeSinglyLinkedListTest.java
index 0f0577d39094..10f6b8536b19 100644
--- a/src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/PalindromeSinglyLinkedListTest.java
@@ -1,9 +1,8 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.datastructures.lists;
 
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import com.thealgorithms.datastructures.lists.SinglyLinkedList;
 import org.junit.jupiter.api.Test;
 
 public class PalindromeSinglyLinkedListTest {
diff --git a/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java b/src/test/java/com/thealgorithms/maths/LowestBasePalindromeTest.java
similarity index 99%
rename from src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java
rename to src/test/java/com/thealgorithms/maths/LowestBasePalindromeTest.java
index 7c3ce6635aa0..5a3d1c64b379 100644
--- a/src/test/java/com/thealgorithms/others/LowestBasePalindromeTest.java
+++ b/src/test/java/com/thealgorithms/maths/LowestBasePalindromeTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.others;
+package com.thealgorithms.maths;
 
 import java.util.ArrayList;
 import java.util.Arrays;
diff --git a/src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java b/src/test/java/com/thealgorithms/maths/PalindromePrimeTest.java
similarity index 98%
rename from src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java
rename to src/test/java/com/thealgorithms/maths/PalindromePrimeTest.java
index 130cd19b47b1..2405da558700 100644
--- a/src/test/java/com/thealgorithms/misc/PalindromePrimeTest.java
+++ b/src/test/java/com/thealgorithms/maths/PalindromePrimeTest.java
@@ -1,4 +1,4 @@
-package com.thealgorithms.misc;
+package com.thealgorithms.maths;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;

From 31caee6ef850e0610f1fd0b49668b395a5613f71 Mon Sep 17 00:00:00 2001
From: Rosander0 <astereen.0107@gmail.com>
Date: Thu, 25 Jun 2026 14:01:26 +0530
Subject: [PATCH 1287/1338] Add TitleCase Implementation (#7473)

feat: add TitleCase implementation
---
 .../com/thealgorithms/strings/TitleCase.java  | 54 +++++++++++++++++++
 .../thealgorithms/strings/TitleCaseTest.java  | 39 ++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/strings/TitleCase.java
 create mode 100644 src/test/java/com/thealgorithms/strings/TitleCaseTest.java

diff --git a/src/main/java/com/thealgorithms/strings/TitleCase.java b/src/main/java/com/thealgorithms/strings/TitleCase.java
new file mode 100644
index 000000000000..eb6c73623681
--- /dev/null
+++ b/src/main/java/com/thealgorithms/strings/TitleCase.java
@@ -0,0 +1,54 @@
+package com.thealgorithms.strings;
+
+/**
+ * Title Case converts a string so that the first letter of each word
+ * is capitalized and the rest are lowercase.
+ * Example: "the quick brown fox" -> "The Quick Brown Fox"
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Title_case">
+ *     Wikipedia: Title Case</a>
+ */
+public final class TitleCase {
+
+    private TitleCase() {
+        // Utility class
+    }
+
+    /**
+     * Converts a string to title case.
+     *
+     * @param input The string to convert
+     * @return The title-cased string, or empty string if input is null/empty.
+     *     If input contains only whitespace, it is returned as is.
+     */
+    public static String toTitleCase(final String input) {
+        if (input == null || input.isEmpty()) {
+            return "";
+        }
+
+        StringBuilder result = new StringBuilder(input.length());
+        boolean capitalizeNext = true;
+        for (int i = 0; i < input.length(); i++) {
+            char c = input.charAt(i);
+            if (Character.isWhitespace(c)) {
+                capitalizeNext = true;
+                result.append(c);
+                continue;
+            }
+
+            if (capitalizeNext) {
+                if (Character.isLetter(c)) {
+                    result.append(Character.toUpperCase(c));
+                    capitalizeNext = false;
+                } else {
+                    // Keep capitalizeNext=true so the first *letter* after
+                    // punctuation/digits is capitalized.
+                    result.append(c);
+                }
+            } else {
+                result.append(Character.toLowerCase(c));
+            }
+        }
+        return result.toString();
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/TitleCaseTest.java b/src/test/java/com/thealgorithms/strings/TitleCaseTest.java
new file mode 100644
index 000000000000..37bb44ed2c7b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/strings/TitleCaseTest.java
@@ -0,0 +1,39 @@
+package com.thealgorithms.strings;
+// author: Vraj Prajapati @Rosander0
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class TitleCaseTest {
+
+    @Test
+    public void testNullOrEmptyInputs() {
+        assertEquals("", TitleCase.toTitleCase(null));
+        assertEquals("", TitleCase.toTitleCase(""));
+    }
+
+    @Test
+    public void testSingleWord() {
+        assertEquals("Hello", TitleCase.toTitleCase("hello"));
+        assertEquals("Hello", TitleCase.toTitleCase("HELLO"));
+        assertEquals("A", TitleCase.toTitleCase("a"));
+    }
+
+    @Test
+    public void testMultipleWords() {
+        assertEquals("The Quick Brown Fox", TitleCase.toTitleCase("the quick brown fox"));
+        assertEquals("The Quick Brown Fox", TitleCase.toTitleCase("THE QUICK BROWN FOX"));
+        assertEquals("Already Title Case", TitleCase.toTitleCase("already Title Case"));
+    }
+
+    @Test
+    public void testWhitespace() {
+        assertEquals("  Spaces  ", TitleCase.toTitleCase("  spaces  "));
+    }
+
+    @Test
+    public void testQuotedWords() {
+        assertEquals("\"Hello\"", TitleCase.toTitleCase("\"hello\""));
+    }
+}

From ef986c4690e8ea1abda477e685e7133cca09c73d Mon Sep 17 00:00:00 2001
From: iamcodinghere22 <amoghpatwari.25@gmail.com>
Date: Fri, 26 Jun 2026 14:33:46 +0530
Subject: [PATCH 1288/1338]  DisariumNumber (#7490)

* Add SquareFreeInteger to maths

* fix clang-format issues

* add newline

* Add new test file  in test

* modified

* delete

* Add DisariumNumbers  with test
---
 .../thealgorithms/maths/DisariumNumber.java   | 37 +++++++++++++++++++
 .../maths/DisariumNumberTest.java             | 32 ++++++++++++++++
 2 files changed, 69 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/DisariumNumber.java
 create mode 100644 src/test/java/com/thealgorithms/maths/DisariumNumberTest.java

diff --git a/src/main/java/com/thealgorithms/maths/DisariumNumber.java b/src/main/java/com/thealgorithms/maths/DisariumNumber.java
new file mode 100644
index 000000000000..0196d0797bcc
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/DisariumNumber.java
@@ -0,0 +1,37 @@
+package com.thealgorithms.maths;
+
+/**
+ * Disarium number is a number where the sum of its digits powered
+ * with their respective positions is equal to the number itself.
+ * Example: 135 = 1^1 + 3^2 + 5^3 = 1 + 9 + 125 = 135
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Disarium_number">Disarium Number</a>
+ */
+public final class DisariumNumber {
+
+    private DisariumNumber() {
+    }
+
+    /**
+     * Checks if a number is a Disarium number.
+     *
+     * @param number the number to check (must be positive)
+     * @return true if number is Disarium, false otherwise
+     * @throws IllegalArgumentException if number is not positive
+     */
+    public static boolean isDisarium(int number) {
+        if (number <= 0) {
+            throw new IllegalArgumentException("Input must be a positive integer.");
+        }
+        int digits = String.valueOf(number).length();
+        int temp = number;
+        int sum = 0;
+        while (temp > 0) {
+            int lastDigit = temp % 10;
+            sum += (int) Math.pow(lastDigit, digits);
+            digits--;
+            temp /= 10;
+        }
+        return sum == number;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/DisariumNumberTest.java b/src/test/java/com/thealgorithms/maths/DisariumNumberTest.java
new file mode 100644
index 000000000000..54e9e861ad44
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/DisariumNumberTest.java
@@ -0,0 +1,32 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class DisariumNumberTest {
+
+    @Test
+    void testDisariumNumbers() {
+        assertTrue(DisariumNumber.isDisarium(1));
+        assertTrue(DisariumNumber.isDisarium(89));
+        assertTrue(DisariumNumber.isDisarium(135));
+        assertTrue(DisariumNumber.isDisarium(175));
+        assertTrue(DisariumNumber.isDisarium(518));
+    }
+
+    @Test
+    void testNonDisariumNumbers() {
+        assertFalse(DisariumNumber.isDisarium(10));
+        assertFalse(DisariumNumber.isDisarium(100));
+        assertFalse(DisariumNumber.isDisarium(200));
+    }
+
+    @Test
+    void testInvalidInput() {
+        assertThrows(IllegalArgumentException.class, () -> DisariumNumber.isDisarium(0));
+        assertThrows(IllegalArgumentException.class, () -> DisariumNumber.isDisarium(-5));
+    }
+}

From 0d29e7c167db8dcf07032b9112515d8cc42bbc5f Mon Sep 17 00:00:00 2001
From: JulianGStudium <julian-michael.goerlich@informatik.hs-fulda.de>
Date: Sat, 27 Jun 2026 10:38:11 +0200
Subject: [PATCH 1289/1338] SelectionSort: add missing Javadoc for class and
 findIndexOfMin method (#7494)

* SelectionSort: add missing Javadoc for class and findIndexOfMin method

* fix: add missing newline at end of file
---
 .../com/thealgorithms/sorts/SelectionSort.java | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/SelectionSort.java b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
index 2d1814441701..e6d1a16a7af7 100644
--- a/src/main/java/com/thealgorithms/sorts/SelectionSort.java
+++ b/src/main/java/com/thealgorithms/sorts/SelectionSort.java
@@ -1,5 +1,10 @@
 package com.thealgorithms.sorts;
 
+/**
+ * Implementation of the Selection Sort algorithm.
+ *
+ * @see SortAlgorithm
+ */
 public class SelectionSort implements SortAlgorithm {
     /**
      * Generic Selection Sort algorithm.
@@ -11,11 +16,12 @@ public class SelectionSort implements SortAlgorithm {
      *
      * Space Complexity: O(1) – in-place sorting.
      *
-     * @see SortAlgorithm
+     * @param array the array to be sorted
+     * @param <T> the type of elements in the array
+     * @return the sorted array
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
-
         for (int i = 0; i < array.length - 1; i++) {
             final int minIndex = findIndexOfMin(array, i);
             SortUtils.swap(array, i, minIndex);
@@ -23,6 +29,14 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         return array;
     }
 
+    /**
+     * Finds the index of the minimum element in the array starting from a given index.
+     *
+     * @param array the array to search
+     * @param startIndex the index to start searching from
+     * @param <T> the type of elements in the array
+     * @return the index of the minimum element
+     */
     private static <T extends Comparable<T>> int findIndexOfMin(T[] array, final int startIndex) {
         int minIndex = startIndex;
         for (int i = startIndex + 1; i < array.length; i++) {

From e3692c75d4e18750171ef3350c983bd91f890650 Mon Sep 17 00:00:00 2001
From: DishaSethi <142926792+DishaSethi@users.noreply.github.com>
Date: Sat, 27 Jun 2026 14:11:37 +0530
Subject: [PATCH 1290/1338] docs: cross-reference nth-fibonacci implementations
 via javadocs (#7497)

* docs: cross-reference nth-fibonacci implementations via javadocs

* style: remove trailing whitespaces in Javadocs

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../dynamicprogramming/Fibonacci.java          | 18 +++++++++++++++---
 .../maths/FibonacciJavaStreams.java            | 18 ++++++++++++++++--
 .../com/thealgorithms/maths/FibonacciLoop.java | 15 +++++++++++++--
 .../maths/FibonacciNumberCheck.java            | 12 ++++++++++++
 .../maths/FibonacciNumberGoldenRation.java     | 12 ++++++++++++
 .../recursion/FibonacciSeries.java             | 12 +++++++++++-
 6 files changed, 79 insertions(+), 8 deletions(-)

diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
index 0d6aff2bbef3..df158112d233 100644
--- a/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
+++ b/src/main/java/com/thealgorithms/dynamicprogramming/Fibonacci.java
@@ -1,10 +1,22 @@
 package com.thealgorithms.dynamicprogramming;
-
 import java.util.HashMap;
 import java.util.Map;
-
 /**
- * @author Varun Upadhyay (https://github.com/varunu28)
+ * Collection of Dynamic Programming techniques to solve for the n-th Fibonacci number.
+ * <p>
+ * This file showcases Top-Down Memoization ({@code fibMemo}), Bottom-Up Tabulation ({@code fibBotUp}),
+ * and Space-Optimized Iteration ({@code fibOptimized}).
+ * <p>
+ * For alternative structural paradigms, mathematical formulas, or verification steps, see:
+ * <ul>
+ * <li>{@link com.thealgorithms.maths.FibonacciLoop} - Standard Iterative (Loop) approach</li>
+ * <li>{@link com.thealgorithms.recursion.FibonacciSeries} - Naive Recursive approach</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciJavaStreams} - Functional approach using Java Streams</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciNumberGoldenRation} - Closed-form expression using Binet's formula</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciNumberCheck} - Utility to check if a given number is a Fibonacci number</li>
+ * <li>{@link com.thealgorithms.matrix.matrixexponentiation.Fibonacci} - O(log n) Matrix Exponentiation approach</li>
+ * </ul>
+ * * @author Varun Upadhyay (https://github.com/varunu28)
  */
 public final class Fibonacci {
     private Fibonacci() {
diff --git a/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java b/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java
index 84390860ccc4..8a93580a4b72 100644
--- a/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java
+++ b/src/main/java/com/thealgorithms/maths/FibonacciJavaStreams.java
@@ -6,9 +6,23 @@
 import java.util.stream.Stream;
 
 /**
- * @author: caos321
- * @date: 14 October 2021 (Thursday)
+ * Calculates Fibonacci numbers using a functional programming paradigm with Java Streams.
+ * <p>
+ * This specific implementation uses {@link java.util.stream.Stream#iterate} and reductions to generate terms.
+ * <p>
+ * For alternative approaches to compute or verify Fibonacci numbers, see:
+ * <ul>
+ * <li>{@link com.thealgorithms.maths.FibonacciLoop} - Standard Iterative (Loop) approach</li>
+ * <li>{@link com.thealgorithms.recursion.FibonacciSeries} - Naive Recursive approach</li>
+ * <li>{@link com.thealgorithms.dynamicprogramming.Fibonacci} - Dynamic Programming approaches (Memoization, Bottom-Up, Optimized)</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciNumberGoldenRation} - Closed-form expression using Binet's formula</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciNumberCheck} - Utility to check if a given number is a Fibonacci number</li>
+ * <li>{@link com.thealgorithms.matrix.matrixexponentiation.Fibonacci} - O(log n) Matrix Exponentiation approach</li>
+ * </ul>
+ * * @author caos321
+ * @date 14 October 2021 (Thursday)
  */
+
 public final class FibonacciJavaStreams {
     private FibonacciJavaStreams() {
     }
diff --git a/src/main/java/com/thealgorithms/maths/FibonacciLoop.java b/src/main/java/com/thealgorithms/maths/FibonacciLoop.java
index de23a4305c3f..f19e3a6969c5 100644
--- a/src/main/java/com/thealgorithms/maths/FibonacciLoop.java
+++ b/src/main/java/com/thealgorithms/maths/FibonacciLoop.java
@@ -1,9 +1,20 @@
 package com.thealgorithms.maths;
-
 import java.math.BigInteger;
-
 /**
  * This class provides methods for calculating Fibonacci numbers using BigInteger for large values of 'n'.
+ * <p>
+ * This specific implementation uses an <b>Iterative approach (Loop)</b> with {@code O(n)} time complexity
+ * and {@code O(1)} space complexity.
+ * <p>
+ * For alternative approaches to compute or verify Fibonacci numbers, see:
+ * <ul>
+ * <li>{@link com.thealgorithms.recursion.FibonacciSeries} - Naive Recursive approach</li>
+ * <li>{@link com.thealgorithms.dynamicprogramming.Fibonacci} - Dynamic Programming approaches (Memoization, Bottom-Up, Optimized)</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciJavaStreams} - Functional approach using Java Streams</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciNumberGoldenRation} - Closed-form expression using Binet's formula</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciNumberCheck} - Utility to check if a given number is a Fibonacci number</li>
+ * <li>{@link com.thealgorithms.matrix.matrixexponentiation.Fibonacci} - O(log n) Matrix Exponentiation approach</li>
+ * </ul>
  */
 public final class FibonacciLoop {
 
diff --git a/src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java b/src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java
index 781275d3130d..6bdc2d6ed9fb 100644
--- a/src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java
+++ b/src/main/java/com/thealgorithms/maths/FibonacciNumberCheck.java
@@ -4,6 +4,18 @@
  * Fibonacci: 0 1 1 2 3 5 8 13 21 ...
  * This code checks Fibonacci Numbers up to 45th number.
  * Other checks fail because of 'long'-type overflow.
+ * <p>
+ * This class serves as a <b>verification utility</b> rather than a generation algorithm.
+ * <p>
+ * For approaches that actively compute the n-th Fibonacci number, see:
+ * <ul>
+ * <li>{@link com.thealgorithms.maths.FibonacciLoop} - Standard Iterative (Loop) approach</li>
+ * <li>{@link com.thealgorithms.recursion.FibonacciSeries} - Naive Recursive approach</li>
+ * <li>{@link com.thealgorithms.dynamicprogramming.Fibonacci} - Dynamic Programming approaches (Memoization, Bottom-Up, Optimized)</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciJavaStreams} - Functional approach using Java Streams</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciNumberGoldenRation} - Closed-form expression using Binet's formula</li>
+ * <li>{@link com.thealgorithms.matrix.matrixexponentiation.Fibonacci} - O(log n) Matrix Exponentiation approach</li>
+ * </ul>
  */
 public final class FibonacciNumberCheck {
     private FibonacciNumberCheck() {
diff --git a/src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java b/src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java
index 4df37a40f541..eca6379b93bc 100644
--- a/src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java
+++ b/src/main/java/com/thealgorithms/maths/FibonacciNumberGoldenRation.java
@@ -3,6 +3,18 @@
 /**
  * This class provides methods for calculating Fibonacci numbers using Binet's formula.
  * Binet's formula is based on the golden ratio and allows computing Fibonacci numbers efficiently.
+ * <p>
+ * This specific implementation provides a closed-form solution with an expected {@code O(1)} time complexity.
+ * <p>
+ * For alternative approaches to compute or verify Fibonacci numbers, see:
+ * <ul>
+ * <li>{@link com.thealgorithms.maths.FibonacciLoop} - Standard Iterative (Loop) approach</li>
+ * <li>{@link com.thealgorithms.recursion.FibonacciSeries} - Naive Recursive approach</li>
+ * <li>{@link com.thealgorithms.dynamicprogramming.Fibonacci} - Dynamic Programming approaches (Memoization, Bottom-Up, Optimized)</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciJavaStreams} - Functional approach using Java Streams</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciNumberCheck} - Utility to check if a given number is a Fibonacci number</li>
+ * <li>{@link com.thealgorithms.matrix.matrixexponentiation.Fibonacci} - O(log n) Matrix Exponentiation approach</li>
+ * </ul>
  *
  * @see <a href="https://en.wikipedia.org/wiki/Fibonacci_sequence#Binet's_formula">Binet's formula on Wikipedia</a>
  */
diff --git a/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java b/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
index 9c809858099e..404adfdf0cf1 100644
--- a/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
+++ b/src/main/java/com/thealgorithms/recursion/FibonacciSeries.java
@@ -7,8 +7,18 @@
  * Example:
  * 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 ...
  * </p>
+ * <p>
+ * This specific implementation demonstrates a <b>Naive Recursive approach</b> with {@code O(2^n)} time complexity.
+ * For more performant variations or different programming paradigms, see:
+ * <ul>
+ * <li>{@link com.thealgorithms.maths.FibonacciLoop} - Standard Iterative (Loop) approach</li>
+ * <li>{@link com.thealgorithms.dynamicprogramming.Fibonacci} - Dynamic Programming variants (Memoization / Bottom-Up)</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciJavaStreams} - Functional approach using Java Streams</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciNumberGoldenRation} - Closed-form expression using Binet's formula</li>
+ * <li>{@link com.thealgorithms.maths.FibonacciNumberCheck} - Utility to check if a given number is a Fibonacci number</li>
+ * <li>{@link com.thealgorithms.matrix.matrixexponentiation.Fibonacci} - O(log n) Matrix Exponentiation approach</li>
+ * </ul>
  */
-
 public final class FibonacciSeries {
     private FibonacciSeries() {
         throw new UnsupportedOperationException("Utility class");

From d4ffef793a6c990977ca6a4d0f0d4dfae9c35c1d Mon Sep 17 00:00:00 2001
From: Simarpreet Singh <simarsaini13@gmail.com>
Date: Mon, 29 Jun 2026 08:17:12 +0100
Subject: [PATCH 1291/1338] Remove duplicate Dijkstra implementation in others
 directory (#7500)

---
 .../com/thealgorithms/others/Dijkstra.java    | 248 ------------------
 1 file changed, 248 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/others/Dijkstra.java

diff --git a/src/main/java/com/thealgorithms/others/Dijkstra.java b/src/main/java/com/thealgorithms/others/Dijkstra.java
deleted file mode 100644
index a379100a2f3b..000000000000
--- a/src/main/java/com/thealgorithms/others/Dijkstra.java
+++ /dev/null
@@ -1,248 +0,0 @@
-package com.thealgorithms.others;
-
-import java.util.HashMap;
-import java.util.Map;
-import java.util.NavigableSet;
-import java.util.TreeSet;
-/**
- * Dijkstra's algorithm,is a graph search algorithm that solves the
- * single-source shortest path problem for a graph with nonnegative edge path
- * costs, producing a shortest path tree.
- *
- * <p>
- * NOTE: The inputs to Dijkstra's algorithm are a directed and weighted graph
- * consisting of 2 or more nodes, generally represented by an adjacency matrix
- * or list, and a start node.
- *
- * <p>
- * Original source of code:
- * https://rosettacode.org/wiki/Dijkstra%27s_algorithm#Java Also most of the
- * comments are from RosettaCode.
- */
-public final class Dijkstra {
-    private Dijkstra() {
-    }
-
-    private static final Graph.Edge[] GRAPH = {
-        // Distance from node "a" to node "b" is 7.
-        // In the current Graph there is no way to move the other way (e,g, from "b" to "a"),
-        // a new edge would be needed for that
-        new Graph.Edge("a", "b", 7),
-        new Graph.Edge("a", "c", 9),
-        new Graph.Edge("a", "f", 14),
-        new Graph.Edge("b", "c", 10),
-        new Graph.Edge("b", "d", 15),
-        new Graph.Edge("c", "d", 11),
-        new Graph.Edge("c", "f", 2),
-        new Graph.Edge("d", "e", 6),
-        new Graph.Edge("e", "f", 9),
-    };
-    private static final String START = "a";
-    private static final String END = "e";
-
-    /**
-     * main function Will run the code with "GRAPH" that was defined above.
-     */
-    public static void main(String[] args) {
-        Graph g = new Graph(GRAPH);
-        g.dijkstra(START);
-        g.printPath(END);
-        // g.printAllPaths();
-    }
-}
-
-class Graph {
-
-    // mapping of vertex names to Vertex objects, built from a set of Edges
-
-    private final Map<String, Vertex> graph;
-
-    /**
-     * One edge of the graph (only used by Graph constructor)
-     */
-    public static class Edge {
-
-        public final String v1;
-        public final String v2;
-        public final int dist;
-
-        Edge(String v1, String v2, int dist) {
-            this.v1 = v1;
-            this.v2 = v2;
-            this.dist = dist;
-        }
-    }
-
-    /**
-     * One vertex of the graph, complete with mappings to neighbouring vertices
-     */
-    public static class Vertex implements Comparable<Vertex> {
-
-        public final String name;
-        // MAX_VALUE assumed to be infinity
-        public int dist = Integer.MAX_VALUE;
-        public Vertex previous = null;
-        public final Map<Vertex, Integer> neighbours = new HashMap<>();
-
-        Vertex(String name) {
-            this.name = name;
-        }
-
-        private void printPath() {
-            if (this == this.previous) {
-                System.out.printf("%s", this.name);
-            } else if (this.previous == null) {
-                System.out.printf("%s(unreached)", this.name);
-            } else {
-                this.previous.printPath();
-                System.out.printf(" -> %s(%d)", this.name, this.dist);
-            }
-        }
-
-        public int compareTo(Vertex other) {
-            if (dist == other.dist) {
-                return name.compareTo(other.name);
-            }
-
-            return Integer.compare(dist, other.dist);
-        }
-
-        @Override
-        public boolean equals(Object object) {
-            if (this == object) {
-                return true;
-            }
-            if (object == null || getClass() != object.getClass()) {
-                return false;
-            }
-            if (!super.equals(object)) {
-                return false;
-            }
-
-            Vertex vertex = (Vertex) object;
-
-            if (dist != vertex.dist) {
-                return false;
-            }
-            if (name != null ? !name.equals(vertex.name) : vertex.name != null) {
-                return false;
-            }
-            if (previous != null ? !previous.equals(vertex.previous) : vertex.previous != null) {
-                return false;
-            }
-            return neighbours != null ? neighbours.equals(vertex.neighbours) : vertex.neighbours == null;
-        }
-
-        @Override
-        public int hashCode() {
-            int result = super.hashCode();
-            result = 31 * result + (name != null ? name.hashCode() : 0);
-            result = 31 * result + dist;
-            result = 31 * result + (previous != null ? previous.hashCode() : 0);
-            result = 31 * result + (neighbours != null ? neighbours.hashCode() : 0);
-            return result;
-        }
-
-        @Override
-        public String toString() {
-            return "(" + name + ", " + dist + ")";
-        }
-    }
-
-    /**
-     * Builds a graph from a set of edges
-     */
-    Graph(Edge[] edges) {
-        graph = new HashMap<>(edges.length);
-
-        // one pass to find all vertices
-        for (Edge e : edges) {
-            if (!graph.containsKey(e.v1)) {
-                graph.put(e.v1, new Vertex(e.v1));
-            }
-            if (!graph.containsKey(e.v2)) {
-                graph.put(e.v2, new Vertex(e.v2));
-            }
-        }
-
-        // another pass to set neighbouring vertices
-        for (Edge e : edges) {
-            graph.get(e.v1).neighbours.put(graph.get(e.v2), e.dist);
-            // graph.get(e.v2).neighbours.put(graph.get(e.v1), e.dist); // also do this for an
-            // undirected graph
-        }
-    }
-
-    /**
-     * Runs dijkstra using a specified source vertex
-     */
-    public void dijkstra(String startName) {
-        if (!graph.containsKey(startName)) {
-            System.err.printf("Graph doesn't contain start vertex \"%s\"%n", startName);
-            return;
-        }
-        final Vertex source = graph.get(startName);
-        NavigableSet<Vertex> q = new TreeSet<>();
-
-        // set-up vertices
-        for (Vertex v : graph.values()) {
-            v.previous = v == source ? source : null;
-            v.dist = v == source ? 0 : Integer.MAX_VALUE;
-            q.add(v);
-        }
-
-        dijkstra(q);
-    }
-
-    /**
-     * Implementation of dijkstra's algorithm using a binary heap.
-     */
-    private void dijkstra(final NavigableSet<Vertex> q) {
-        Vertex u;
-        Vertex v;
-        while (!q.isEmpty()) {
-            // vertex with shortest distance (first iteration will return source)
-            u = q.pollFirst();
-            if (u.dist == Integer.MAX_VALUE) {
-                break; // we can ignore u (and any other remaining vertices) since they are
-                       // unreachable
-            }
-            // look at distances to each neighbour
-            for (Map.Entry<Vertex, Integer> a : u.neighbours.entrySet()) {
-                v = a.getKey(); // the neighbour in this iteration
-
-                final int alternateDist = u.dist + a.getValue();
-                if (alternateDist < v.dist) { // shorter path to neighbour found
-                    q.remove(v);
-                    v.dist = alternateDist;
-                    v.previous = u;
-                    q.add(v);
-                }
-            }
-        }
-    }
-
-    /**
-     * Prints a path from the source to the specified vertex
-     */
-    public void printPath(String endName) {
-        if (!graph.containsKey(endName)) {
-            System.err.printf("Graph doesn't contain end vertex \"%s\"%n", endName);
-            return;
-        }
-
-        graph.get(endName).printPath();
-        System.out.println();
-    }
-
-    /**
-     * Prints the path from the source to every vertex (output order is not
-     * guaranteed)
-     */
-    public void printAllPaths() {
-        for (Vertex v : graph.values()) {
-            v.printPath();
-            System.out.println();
-        }
-    }
-}

From 676175dd3725f5ca3a6bac4de38e7612f9818907 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 29 Jun 2026 10:46:43 +0200
Subject: [PATCH 1292/1338] chore(deps): bump org.junit:junit-bom from 6.1.0 to
 6.1.1 (#7501)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 6.1.0 to 6.1.1.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r6.1.0...r6.1.1)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 6.1.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 927395112259..2b17730cdffb 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>6.1.0</version>
+                <version>6.1.1</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 12aab706ab3980efd968810c0489b146db23cec6 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 29 Jun 2026 08:50:22 +0000
Subject: [PATCH 1293/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.6.0 to 13.7.0 (#7502)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.6.0 to 13.7.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.6.0...checkstyle-13.7.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.7.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 2b17730cdffb..5ba6c1848510 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.6.0</version>
+                    <version>13.7.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From c6fa50fb0c2970891de6bc30012ffa4b115695a9 Mon Sep 17 00:00:00 2001
From: Herley <33199364+herley-shaori@users.noreply.github.com>
Date: Sat, 4 Jul 2026 04:09:47 +0700
Subject: [PATCH 1294/1338] =?UTF-8?q?docs:=20correct=20stale=20WiggleSort?=
 =?UTF-8?q?=20Javadoc=20=E2=80=94=20[1,=202,=202]=20is=20already=20detecte?=
 =?UTF-8?q?d,=20add=20regression=20tests=20(#7509)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

docs: correct stale WiggleSort Javadoc about undetected inputs

The class Javadoc claimed [1, 2, 2] slips through undetected, but the
odd-array median guard added later in wiggleSort() already catches
exactly that case and throws IllegalArgumentException. Update the
Javadoc to describe the current behavior and add regression tests
asserting that [1, 2, 2] and arrays with too many duplicates throw
instead of returning a wrongly ordered result.

Fixes TheAlgorithms/Java#7507
---
 .../com/thealgorithms/sorts/WiggleSort.java   |  6 +++---
 .../thealgorithms/sorts/WiggleSortTest.java   | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/thealgorithms/sorts/WiggleSort.java b/src/main/java/com/thealgorithms/sorts/WiggleSort.java
index c272b820d07a..0349971d1c95 100644
--- a/src/main/java/com/thealgorithms/sorts/WiggleSort.java
+++ b/src/main/java/com/thealgorithms/sorts/WiggleSort.java
@@ -11,9 +11,9 @@
  * https://cs.stackexchange.com/questions/125372/how-to-wiggle-sort-an-array-in-linear-time-complexity
  * Also have a look at:
  * https://cs.stackexchange.com/questions/125372/how-to-wiggle-sort-an-array-in-linear-time-complexity?noredirect=1&lq=1
- * Not all arrays are wiggle-sortable. This algorithm will find some obviously not wiggle-sortable
- * arrays and throw an error, but there are some exceptions that won't be caught, for example [1, 2,
- * 2].
+ * Not all arrays are wiggle-sortable. This algorithm detects non-wiggle-sortable inputs — for
+ * example [1, 2, 2], or arrays where more than half the values are equal — and throws an
+ * IllegalArgumentException instead of returning a wrongly ordered result.
  */
 public class WiggleSort implements SortAlgorithm {
 
diff --git a/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java b/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java
index c5d57d63cf38..0d8b6acf9043 100644
--- a/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/WiggleSortTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.sorts;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.Arrays;
 import org.junit.jupiter.api.Test;
@@ -70,4 +71,22 @@ void wiggleTestStrings() {
         wiggleSort.sort(values);
         assertArrayEquals(values, result);
     }
+
+    @Test
+    void wiggleTestNonWiggleSortableOddArrayThrows() {
+        // [1, 2, 2] is not wiggle-sortable: the median 2 appears ceil(3 / 2) = 2 times
+        // but is not the smallest value, so sorting must fail instead of returning
+        // a wrongly ordered array
+        WiggleSort wiggleSort = new WiggleSort();
+        Integer[] values = {1, 2, 2};
+        assertThrows(IllegalArgumentException.class, () -> wiggleSort.sort(values));
+    }
+
+    @Test
+    void wiggleTestTooManyDuplicatesThrows() {
+        // more than half of the values are the same, which can never be wiggle-sorted
+        WiggleSort wiggleSort = new WiggleSort();
+        Integer[] values = {2, 2, 2, 1};
+        assertThrows(IllegalArgumentException.class, () -> wiggleSort.sort(values));
+    }
 }

From 12ea4bb7aa1879c06be19f9ec5ccea67943d3d1e Mon Sep 17 00:00:00 2001
From: Herley <33199364+herley-shaori@users.noreply.github.com>
Date: Sat, 4 Jul 2026 04:14:28 +0700
Subject: [PATCH 1295/1338] fix: Caesar cipher produces non-alphabetic output
 for negative shifts (#7508)

fix: Caesar cipher produced non-alphabetic output for negative shifts

normalizeShift cast a possibly-negative int directly to char, which
wraps to a huge unsigned 16-bit value (e.g. (char) -1 == 65535). The
subsequent char arithmetic then overflowed and emitted characters
outside the Latin alphabet, e.g. encode("A", -1) returned '@' instead
of 'Z', and the encode/decode round-trip was broken for negative
shifts.

Normalize the shift into the 0..25 range with ((shift % 26) + 26) % 26
and perform the character arithmetic in int, casting back to char only
when appending. Add regression tests covering negative shifts and the
encode/decode round-trip.

Fixes TheAlgorithms/Java#7506
---
 .../com/thealgorithms/ciphers/Caesar.java     | 31 +++++++++----------
 .../com/thealgorithms/ciphers/CaesarTest.java | 23 ++++++++++++++
 2 files changed, 37 insertions(+), 17 deletions(-)

diff --git a/src/main/java/com/thealgorithms/ciphers/Caesar.java b/src/main/java/com/thealgorithms/ciphers/Caesar.java
index 23535bc2b5d2..7a5e70e6eb78 100644
--- a/src/main/java/com/thealgorithms/ciphers/Caesar.java
+++ b/src/main/java/com/thealgorithms/ciphers/Caesar.java
@@ -9,8 +9,8 @@
  * @author khalil2535
  */
 public class Caesar {
-    private static char normalizeShift(final int shift) {
-        return (char) (shift % 26);
+    private static int normalizeShift(final int shift) {
+        return ((shift % 26) + 26) % 26;
     }
 
     /**
@@ -22,21 +22,18 @@ private static char normalizeShift(final int shift) {
     public String encode(String message, int shift) {
         StringBuilder encoded = new StringBuilder();
 
-        final char shiftChar = normalizeShift(shift);
+        final int shiftChar = normalizeShift(shift);
 
         final int length = message.length();
         for (int i = 0; i < length; i++) {
-            //            int current = message.charAt(i); //using char to shift characters because
-            //            ascii
-            // is in-order latin alphabet
-            char current = message.charAt(i); // Java law : char + int = char
+            final char current = message.charAt(i);
 
             if (isCapitalLatinLetter(current)) {
-                current += shiftChar;
-                encoded.append((char) (current > 'Z' ? current - 26 : current)); // 26 = number of latin letters
+                final int shifted = current + shiftChar;
+                encoded.append((char) (shifted > 'Z' ? shifted - 26 : shifted)); // 26 = number of latin letters
             } else if (isSmallLatinLetter(current)) {
-                current += shiftChar;
-                encoded.append((char) (current > 'z' ? current - 26 : current)); // 26 = number of latin letters
+                final int shifted = current + shiftChar;
+                encoded.append((char) (shifted > 'z' ? shifted - 26 : shifted)); // 26 = number of latin letters
             } else {
                 encoded.append(current);
             }
@@ -53,17 +50,17 @@ public String encode(String message, int shift) {
     public String decode(String encryptedMessage, int shift) {
         StringBuilder decoded = new StringBuilder();
 
-        final char shiftChar = normalizeShift(shift);
+        final int shiftChar = normalizeShift(shift);
 
         final int length = encryptedMessage.length();
         for (int i = 0; i < length; i++) {
-            char current = encryptedMessage.charAt(i);
+            final char current = encryptedMessage.charAt(i);
             if (isCapitalLatinLetter(current)) {
-                current -= shiftChar;
-                decoded.append((char) (current < 'A' ? current + 26 : current)); // 26 = number of latin letters
+                final int shifted = current - shiftChar;
+                decoded.append((char) (shifted < 'A' ? shifted + 26 : shifted)); // 26 = number of latin letters
             } else if (isSmallLatinLetter(current)) {
-                current -= shiftChar;
-                decoded.append((char) (current < 'a' ? current + 26 : current)); // 26 = number of latin letters
+                final int shifted = current - shiftChar;
+                decoded.append((char) (shifted < 'a' ? shifted + 26 : shifted)); // 26 = number of latin letters
             } else {
                 decoded.append(current);
             }
diff --git a/src/test/java/com/thealgorithms/ciphers/CaesarTest.java b/src/test/java/com/thealgorithms/ciphers/CaesarTest.java
index 7aa41c4cf423..c8b20ad8d8f9 100644
--- a/src/test/java/com/thealgorithms/ciphers/CaesarTest.java
+++ b/src/test/java/com/thealgorithms/ciphers/CaesarTest.java
@@ -32,6 +32,29 @@ void caesarDecryptTest() {
         assertEquals("Encrypt this text", cipherText);
     }
 
+    @Test
+    void caesarEncryptWithNegativeShiftTest() {
+        // a shift of -1 must wrap 'A' backwards to 'Z', like a shift of +25 would
+        assertEquals("Z", caesar.encode("A", -1));
+        assertEquals("z", caesar.encode("a", -1));
+        assertEquals("EBIIL", caesar.encode("HELLO", -3));
+    }
+
+    @Test
+    void caesarDecryptWithNegativeShiftTest() {
+        assertEquals("A", caesar.decode("Z", -1));
+        assertEquals("HELLO", caesar.decode("EBIIL", -3));
+    }
+
+    @Test
+    void caesarNegativeShiftRoundTripTest() {
+        // encode followed by decode with the same shift must return the original text
+        for (int shift : new int[] {-1, -5, -25, -26, -27, -52}) {
+            String message = "The quick brown Fox";
+            assertEquals(message, caesar.decode(caesar.encode(message, shift), shift));
+        }
+    }
+
     @Test
     void caesarBruteForce() {
         // given

From 8304c1e93250fca3404046ee9914257c91a9d545 Mon Sep 17 00:00:00 2001
From: OrbisAI Security <mediratta01.pally@gmail.com>
Date: Sat, 4 Jul 2026 17:01:38 +0530
Subject: [PATCH 1296/1338] fix: this dependabot configuration does not set a
 co... in... (#7510)

fix: package_managers.dependabot.dependabot-missing-cooldown.dependabot-missing-cooldown security vulnerability

Automated security fix generated by OrbisAI Security
---
 .github/dependabot.yml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 2e5622f7b51d..1b91763b2d53 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -5,14 +5,20 @@ updates:
     directory: "/"
     schedule:
       interval: "weekly"
+    cooldown:
+      default-days: 7
 
   - package-ecosystem: "github-actions"
     directory: "/.github/workflows/"
     schedule:
       interval: "daily"
+    cooldown:
+      default-days: 7
 
   - package-ecosystem: "maven"
     directory: "/"
     schedule:
       interval: "daily"
+    cooldown:
+      default-days: 7
 ...

From c49837965842d0e5e647ed886f72305fc1dbf369 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 4 Jul 2026 16:32:04 +0200
Subject: [PATCH 1297/1338] chore(deps): bump github/codeql-action from 4 to
 4.36.2 in /.github/workflows (#7511)

chore(deps): bump github/codeql-action in /.github/workflows

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4 to 4.36.2.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v4...v4.36.2)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: 4.36.2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 14ea223946cd..9af40d55669f 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4
+        uses: github/codeql-action/init@v4.36.2
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4
+        uses: github/codeql-action/analyze@v4.36.2
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4
+        uses: github/codeql-action/init@v4.36.2
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4
+        uses: github/codeql-action/analyze@v4.36.2
         with:
           category: "/language:actions"
 ...

From 80fc2bdcd637d9f03afe40f8e13b8e882c183cf4 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 7 Jul 2026 23:47:18 +0200
Subject: [PATCH 1298/1338] chore(deps): bump actions/setup-java from 5 to
 5.4.0 in /.github/workflows (#7516)

chore(deps): bump actions/setup-java in /.github/workflows

Bumps [actions/setup-java](https://github.com/actions/setup-java) from 5 to 5.4.0.
- [Release notes](https://github.com/actions/setup-java/releases)
- [Commits](https://github.com/actions/setup-java/compare/v5...v5.4.0)

---
updated-dependencies:
- dependency-name: actions/setup-java
  dependency-version: 5.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml  | 2 +-
 .github/workflows/codeql.yml | 2 +-
 .github/workflows/infer.yml  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b8f4c8efa7e6..9cbb567747a6 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@v7
       - name: Set up JDK
-        uses: actions/setup-java@v5
+        uses: actions/setup-java@v5.4.0
         with:
           java-version: 21
           distribution: 'temurin'
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 9af40d55669f..3fb71c5cf267 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -24,7 +24,7 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Set up JDK
-        uses: actions/setup-java@v5
+        uses: actions/setup-java@v5.4.0
         with:
           java-version: 21
           distribution: 'temurin'
diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index 6bf5c56a91b1..9c095908d777 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -18,7 +18,7 @@ jobs:
       - uses: actions/checkout@v7
 
       - name: Set up JDK
-        uses: actions/setup-java@v5
+        uses: actions/setup-java@v5.4.0
         with:
           java-version: 21
           distribution: 'temurin'

From fd2858e7e6138d9f8940ee9820e172912a5acfb4 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 10 Jul 2026 00:14:47 +0200
Subject: [PATCH 1299/1338] chore(deps): bump github/codeql-action from 4.36.2
 to 4.36.3 in /.github/workflows (#7519)

chore(deps): bump github/codeql-action in /.github/workflows

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4.36.2 to 4.36.3.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v4.36.2...v4.36.3)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: 4.36.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 3fb71c5cf267..a4389ee0ffcb 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.36.2
+        uses: github/codeql-action/init@v4.36.3
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.36.2
+        uses: github/codeql-action/analyze@v4.36.3
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.36.2
+        uses: github/codeql-action/init@v4.36.3
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.36.2
+        uses: github/codeql-action/analyze@v4.36.3
         with:
           category: "/language:actions"
 ...

From 967348368ef77f387f1f634439ce378f89591bbc Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 11 Jul 2026 01:16:57 +0300
Subject: [PATCH 1300/1338] chore(deps): bump actions/stale from 10 to 10.3.0
 in /.github/workflows (#7522)

Bumps [actions/stale](https://github.com/actions/stale) from 10 to 10.3.0.
- [Release notes](https://github.com/actions/stale/releases)
- [Changelog](https://github.com/actions/stale/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/stale/compare/v10...v10.3.0)

---
updated-dependencies:
- dependency-name: actions/stale
  dependency-version: 10.3.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/stale.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index bb613daf8f1d..2c8934bae274 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -11,7 +11,7 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/stale@v10
+      - uses: actions/stale@v10.3.0
         with:
           stale-issue-message: 'This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution!'
           close-issue-message: 'Please reopen this issue once you have made the required changes. If you need help, feel free to ask in our [Discord](https://the-algorithms.com/discord) server or ping one of the maintainers here. Thank you for your contribution!'

From 9b16a48f1f76b934ceb9ebd2c2f6886c6b9d6153 Mon Sep 17 00:00:00 2001
From: akankshanimmagadda <akankshanimmagadda@gmail.com>
Date: Mon, 13 Jul 2026 17:01:25 +0530
Subject: [PATCH 1301/1338] Enhance Javadoc for AccountMerge (#7523)

add detailed Javadocs to AccountMerge file in graph Algorithms

Co-authored-by: akanksha <akankshanimmagadda@gmai.com>
---
 .../com/thealgorithms/graph/AccountMerge.java | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/thealgorithms/graph/AccountMerge.java b/src/main/java/com/thealgorithms/graph/AccountMerge.java
index cf934a72eb68..86f0a24b6c1c 100644
--- a/src/main/java/com/thealgorithms/graph/AccountMerge.java
+++ b/src/main/java/com/thealgorithms/graph/AccountMerge.java
@@ -10,13 +10,25 @@
 /**
  * Merges account records using Disjoint Set Union (Union-Find) on shared emails.
  *
- * <p>Input format: each account is a list where the first element is the user name and the
- * remaining elements are emails.
+ * <p>Each account is expected to be a list where the first element is the user name and the
+ * remaining elements are email addresses. Accounts that share at least one email are merged into a
+ * single record.
  */
 public final class AccountMerge {
     private AccountMerge() {
+        // Utility class; do not instantiate.
     }
 
+    /**
+     * Merges accounts that share one or more email addresses.
+     *
+     * <p>The returned list is sorted by account owner name, then by the first email address when
+     * multiple merged groups have the same owner name. Within each merged account, emails are
+     * returned in lexicographic order.
+     *
+     * @param accounts a list of accounts where each entry contains a user name followed by emails
+     * @return merged accounts, or an empty list when {@code accounts} is null or empty
+     */
     public static List<List<String>> mergeAccounts(List<List<String>> accounts) {
         if (accounts == null || accounts.isEmpty()) {
             return List.of();
@@ -73,6 +85,9 @@ public static List<List<String>> mergeAccounts(List<List<String>> accounts) {
         return merged;
     }
 
+    /**
+     * Lightweight union-find structure with path compression and union by rank.
+     */
     private static final class UnionFind {
         private final int[] parent;
         private final int[] rank;

From 0125123383c450f3119dbd42ae0b4031f793e2f5 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 15 Jul 2026 09:53:59 +0300
Subject: [PATCH 1302/1338] chore(deps): bump actions/setup-java from 5.4.0 to
 5.5.0 in /.github/workflows (#7525)

chore(deps): bump actions/setup-java in /.github/workflows

Bumps [actions/setup-java](https://github.com/actions/setup-java) from 5.4.0 to 5.5.0.
- [Release notes](https://github.com/actions/setup-java/releases)
- [Commits](https://github.com/actions/setup-java/compare/v5.4.0...v5.5.0)

---
updated-dependencies:
- dependency-name: actions/setup-java
  dependency-version: 5.5.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml  | 2 +-
 .github/workflows/codeql.yml | 2 +-
 .github/workflows/infer.yml  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 9cbb567747a6..eb5657a9408c 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@v7
       - name: Set up JDK
-        uses: actions/setup-java@v5.4.0
+        uses: actions/setup-java@v5.5.0
         with:
           java-version: 21
           distribution: 'temurin'
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index a4389ee0ffcb..69794d037aaa 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -24,7 +24,7 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Set up JDK
-        uses: actions/setup-java@v5.4.0
+        uses: actions/setup-java@v5.5.0
         with:
           java-version: 21
           distribution: 'temurin'
diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index 9c095908d777..1cef578633de 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -18,7 +18,7 @@ jobs:
       - uses: actions/checkout@v7
 
       - name: Set up JDK
-        uses: actions/setup-java@v5.4.0
+        uses: actions/setup-java@v5.5.0
         with:
           java-version: 21
           distribution: 'temurin'

From e45b6ac1400b37e80f9ccca446324d7f86f8f998 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 16 Jul 2026 00:47:58 +0300
Subject: [PATCH 1303/1338] chore(deps): bump github/codeql-action from 4.36.3
 to 4.37.0 in /.github/workflows (#7526)

chore(deps): bump github/codeql-action in /.github/workflows

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4.36.3 to 4.37.0.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v4.36.3...v4.37.0)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: 4.37.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 69794d037aaa..3cd8fc7dfa56 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.36.3
+        uses: github/codeql-action/init@v4.37.0
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.36.3
+        uses: github/codeql-action/analyze@v4.37.0
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.36.3
+        uses: github/codeql-action/init@v4.37.0
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.36.3
+        uses: github/codeql-action/analyze@v4.37.0
         with:
           category: "/language:actions"
 ...

From 406347ce46908a6e30f7a5b078b8769c588a7f49 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 17 Jul 2026 01:07:44 +0300
Subject: [PATCH 1304/1338] chore(deps): bump actions/stale from 10.3.0 to
 10.4.0 in /.github/workflows (#7527)

chore(deps): bump actions/stale in /.github/workflows

Bumps [actions/stale](https://github.com/actions/stale) from 10.3.0 to 10.4.0.
- [Release notes](https://github.com/actions/stale/releases)
- [Changelog](https://github.com/actions/stale/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/stale/compare/v10.3.0...v10.4.0)

---
updated-dependencies:
- dependency-name: actions/stale
  dependency-version: 10.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/stale.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index 2c8934bae274..c94d2040aac4 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -11,7 +11,7 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/stale@v10.3.0
+      - uses: actions/stale@v10.4.0
         with:
           stale-issue-message: 'This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution!'
           close-issue-message: 'Please reopen this issue once you have made the required changes. If you need help, feel free to ask in our [Discord](https://the-algorithms.com/discord) server or ping one of the maintainers here. Thank you for your contribution!'

From 93cf85e1f4e24a375588cc139a19f538ecb3db73 Mon Sep 17 00:00:00 2001
From: Rosander0 <213166773+Rosander0@users.noreply.github.com>
Date: Sun, 19 Jul 2026 16:55:04 +0530
Subject: [PATCH 1305/1338] Add LinearRegression Implementation (#7520)

feat: Add Linear Regression Implementation
---
 .../machinelearning/LinearRegression.java     | 102 ++++++++++++++++++
 .../machinelearning/LinearRegressionTest.java |  95 ++++++++++++++++
 2 files changed, 197 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/machinelearning/LinearRegression.java
 create mode 100644 src/test/java/com/thealgorithms/machinelearning/LinearRegressionTest.java

diff --git a/src/main/java/com/thealgorithms/machinelearning/LinearRegression.java b/src/main/java/com/thealgorithms/machinelearning/LinearRegression.java
new file mode 100644
index 000000000000..134d4eee8c4c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/machinelearning/LinearRegression.java
@@ -0,0 +1,102 @@
+package com.thealgorithms.machinelearning;
+
+/**
+ * A simple Linear Regression model implemented from scratch using Gradient Descent.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Linear_regression">Linear Regression (Wikipedia)</a>
+ * @author Vraj Prajapati (Rosander0)
+ */
+public class LinearRegression {
+    private double m; // Slope (weight)
+    private double b; // Y-intercept (bias)
+    private final double learningRate;
+    private final int epochs;
+
+    /**
+     * Constructs a Linear Regression model with the given hyperparameters.
+     *
+     * @param learningRate controls the step size during gradient descent
+     * @param epochs the number of iterations to train the model
+     */
+    public LinearRegression(double learningRate, int epochs) {
+        this.learningRate = learningRate;
+        this.epochs = epochs;
+        this.m = 0.0;
+        this.b = 0.0;
+    }
+
+    /**
+     * Trains the model on the provided dataset using batch gradient descent.
+     *
+     * @param x the input feature values
+     * @param y the corresponding target values
+     * @throws IllegalArgumentException if the arrays are null, empty, or of differing lengths
+     */
+    public void fit(double[] x, double[] y) {
+        if (x == null || y == null || x.length != y.length || x.length == 0) {
+            throw new IllegalArgumentException("X and Y must be non-null, non-empty, and of the same length.");
+        }
+
+        int n = x.length;
+
+        for (int epoch = 0; epoch < epochs; epoch++) {
+            double mGradient = 0;
+            double bGradient = 0;
+
+            // Calculate gradients across the entire dataset
+            for (int i = 0; i < n; i++) {
+                double prediction = (m * x[i]) + b;
+                double error = prediction - y[i];
+
+                // Partial derivatives of the Mean Squared Error cost function
+                mGradient += error * x[i];
+                bGradient += error;
+            }
+
+            // Average the gradients and update the parameters
+            m -= 2.0 / n * mGradient * learningRate;
+            b -= 2.0 / n * bGradient * learningRate;
+        }
+    }
+
+    /**
+     * Predicts the output for a given input x.
+     *
+     * @param x the input value
+     * @return the predicted output
+     */
+    public double predict(double x) {
+        return (m * x) + b;
+    }
+
+    /**
+     * Calculates the Mean Squared Error of the model against a dataset.
+     *
+     * @param x the input feature values
+     * @param y the corresponding target values
+     * @return the mean squared error
+     */
+    public double calculateMSE(double[] x, double[] y) {
+        double totalSquaredError = 0;
+        int n = x.length;
+        for (int i = 0; i < n; i++) {
+            double error = predict(x[i]) - y[i];
+            totalSquaredError += error * error;
+        }
+        return totalSquaredError / n;
+    }
+
+    /**
+     * @return the learned slope of the regression line
+     */
+    public double getSlope() {
+        return m;
+    }
+
+    /**
+     * @return the learned y-intercept of the regression line
+     */
+    public double getIntercept() {
+        return b;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/machinelearning/LinearRegressionTest.java b/src/test/java/com/thealgorithms/machinelearning/LinearRegressionTest.java
new file mode 100644
index 000000000000..e8a130d0ccb2
--- /dev/null
+++ b/src/test/java/com/thealgorithms/machinelearning/LinearRegressionTest.java
@@ -0,0 +1,95 @@
+package com.thealgorithms.machinelearning;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class LinearRegressionTest {
+
+    private static final double DELTA = 0.1;
+
+    @Test
+    void fitLearnsCorrectSlopeAndIntercept() {
+        double trueM = 2.5;
+        double trueB = 1.5;
+
+        double[] xTrain = {1.0, 2.0, 3.0, 4.0, 5.0, 6.0};
+        double[] yTrain = new double[xTrain.length];
+        for (int i = 0; i < xTrain.length; i++) {
+            yTrain[i] = (trueM * xTrain[i]) + trueB;
+        }
+
+        LinearRegression model = new LinearRegression(0.01, 1000);
+        model.fit(xTrain, yTrain);
+
+        assertEquals(trueM, model.getSlope(), DELTA);
+        assertEquals(trueB, model.getIntercept(), DELTA);
+    }
+
+    @Test
+    void predictMatchesExpectedOnUnseenData() {
+        double trueM = 2.5;
+        double trueB = 1.5;
+
+        double[] xTrain = {1.0, 2.0, 3.0, 4.0, 5.0, 6.0};
+        double[] yTrain = new double[xTrain.length];
+        for (int i = 0; i < xTrain.length; i++) {
+            yTrain[i] = (trueM * xTrain[i]) + trueB;
+        }
+
+        LinearRegression model = new LinearRegression(0.01, 1000);
+        model.fit(xTrain, yTrain);
+
+        double[] testInputs = {0.0, 3.5, 7.0};
+        for (double testX : testInputs) {
+            double expectedY = (trueM * testX) + trueB;
+            assertEquals(expectedY, model.predict(testX), DELTA);
+        }
+    }
+
+    @Test
+    void calculateMSEIsNearZeroAfterTraining() {
+        double[] xTrain = {1.0, 2.0, 3.0, 4.0, 5.0};
+        double[] yTrain = {3.0, 5.0, 7.0, 9.0, 11.0}; // y = 2x + 1
+
+        LinearRegression model = new LinearRegression(0.01, 1000);
+        model.fit(xTrain, yTrain);
+
+        assertEquals(0.0, model.calculateMSE(xTrain, yTrain), 0.01);
+    }
+
+    @Test
+    void fitThrowsExceptionOnMismatchedArrayLengths() {
+        LinearRegression model = new LinearRegression(0.01, 100);
+        double[] x = {1.0, 2.0};
+        double[] y = {1.0};
+
+        assertThrows(IllegalArgumentException.class, () -> model.fit(x, y));
+    }
+
+    @Test
+    void fitThrowsExceptionOnEmptyArrays() {
+        LinearRegression model = new LinearRegression(0.01, 100);
+        double[] x = {};
+        double[] y = {};
+
+        assertThrows(IllegalArgumentException.class, () -> model.fit(x, y));
+    }
+
+    @Test
+    void fitThrowsExceptionOnNullX() {
+        LinearRegression model = new LinearRegression(0.01, 100);
+        double[] y = {1.0, 2.0};
+
+        assertThrows(IllegalArgumentException.class, () -> model.fit(null, y));
+    }
+
+    @Test
+    void fitThrowsExceptionOnNullY() {
+        LinearRegression model = new LinearRegression(0.01, 100);
+        double[] x = {1.0, 2.0};
+
+        assertThrows(IllegalArgumentException.class, () -> model.fit(x, null));
+    }
+}

From 53fc7643cbddedb576a8e6d4af765703652069b6 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 20 Jul 2026 06:06:09 +0000
Subject: [PATCH 1306/1338] chore(deps): bump actions/setup-python from 6 to
 6.3.0 in /.github/workflows (#7528)

chore(deps): bump actions/setup-python in /.github/workflows

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 6 to 6.3.0.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v6...v6.3.0)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-version: 6.3.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/project_structure.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/project_structure.yml b/.github/workflows/project_structure.yml
index e7e703c27b70..3f27ad13a9cb 100644
--- a/.github/workflows/project_structure.yml
+++ b/.github/workflows/project_structure.yml
@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v7
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@v6.3.0
         with:
           python-version: '3.13'
 

From f34cbbfcae80d3d97e627e1dc4edb7f4db69213b Mon Sep 17 00:00:00 2001
From: Rosander0 <213166773+Rosander0@users.noreply.github.com>
Date: Mon, 20 Jul 2026 12:40:03 +0530
Subject: [PATCH 1307/1338] Add LibrarySort Implementation (#7481)

* feat: add LibrarySort implementation

* major: adding the missing algorithm
---
 .../com/thealgorithms/sorts/LibrarySort.java  | 207 ++++++++++++++++++
 .../thealgorithms/sorts/LibrarySortTest.java  |  70 ++++++
 2 files changed, 277 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/LibrarySort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/LibrarySortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/LibrarySort.java b/src/main/java/com/thealgorithms/sorts/LibrarySort.java
new file mode 100644
index 000000000000..28f16e3016ff
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/LibrarySort.java
@@ -0,0 +1,207 @@
+package com.thealgorithms.sorts;
+
+import java.util.Arrays;
+
+/**
+ * Library Sort (also known as Gapped Insertion Sort) maintains a sparse
+ * working array with gaps distributed between elements, so that most
+ * insertions land directly in an empty gap without shifting anything.
+ * Elements are inserted in rounds that double in size (1, 2, 4, 8, ...);
+ * after each round the array is rebalanced so gaps are spread out evenly
+ * again for the next round.
+ * Time Complexity: O(n log n) expected, O(n^2) worst case if gaps collapse
+ * Space Complexity: O(n)
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Library_sort">
+ *     Wikipedia: Library Sort</a>
+ * @author Vraj Prajapati (@Rosander0)
+ */
+public final class LibrarySort {
+
+    private static final int GAP_FACTOR = 2;
+
+    private LibrarySort() {
+        // Utility class
+    }
+
+    /**
+     * Sorts an array using the Library Sort algorithm.
+     *
+     * @param array the array to sort (must not be null)
+     * @return the sorted array
+     * @throws IllegalArgumentException if {@code array} is {@code null}
+     */
+    public static int[] sort(final int[] array) {
+        if (array == null) {
+            throw new IllegalArgumentException("Input array must not be null.");
+        }
+        if (array.length <= 1) {
+            return array;
+        }
+
+        final int n = array.length;
+        final int capacity = GAP_FACTOR * n;
+        final int[] data = new int[capacity];
+        final boolean[] occupied = new boolean[capacity];
+
+        final int mid = capacity / 2;
+        data[mid] = array[0];
+        occupied[mid] = true;
+
+        int filled = 1;
+        int nextToInsert = 1;
+        int round = 0;
+        while (nextToInsert < n) {
+            final int roundSize = Math.min(1 << round, n - nextToInsert);
+            for (int i = 0; i < roundSize; i++) {
+                insert(data, occupied, array[nextToInsert + i]);
+                filled++;
+            }
+            nextToInsert += roundSize;
+            round++;
+            if (nextToInsert < n) {
+                rebalance(data, occupied, filled);
+            }
+        }
+
+        int idx = 0;
+        for (int i = 0; i < capacity; i++) {
+            if (occupied[i]) {
+                array[idx++] = data[i];
+            }
+        }
+        return array;
+    }
+
+    /**
+     * Inserts {@code value} into the gapped array, placing it directly in an
+     * empty gap when possible, otherwise shifting toward the nearest gap.
+     */
+    private static void insert(final int[] data, final boolean[] occupied, final int value) {
+        final int pos = findInsertionIndex(data, occupied, value);
+        if (pos >= data.length) {
+            insertAtEnd(data, occupied, value);
+            return;
+        }
+
+        if (!occupied[pos]) {
+            data[pos] = value;
+            occupied[pos] = true;
+            return;
+        }
+
+        int right = pos;
+        while (right < data.length && occupied[right]) {
+            right++;
+        }
+        int left = pos - 1;
+        while (left >= 0 && occupied[left]) {
+            left--;
+        }
+
+        final boolean canGoRight = right < data.length;
+        final boolean canGoLeft = left >= 0;
+
+        if (canGoRight && (!canGoLeft || (right - pos) <= (pos - left))) {
+            // Shift data[pos, right) one slot to the right, opening a gap at pos.
+            // occupied[pos] is untouched by the copy and was already true.
+            System.arraycopy(data, pos, data, pos + 1, right - pos);
+            occupied[right] = true;
+            data[pos] = value;
+        } else if (canGoLeft) {
+            // Shift data[left + 1, pos) one slot to the left, opening a gap at pos - 1.
+            // occupied[pos - 1] is untouched by the copy and was already true.
+            System.arraycopy(data, left + 1, data, left, pos - 1 - left);
+            occupied[left] = true;
+            data[pos - 1] = value;
+        } else {
+            // Unreachable in practice: canGoRight and canGoLeft can only both be false if
+            // every slot in this capacity-2n array is occupied, but at most n elements are
+            // ever present at once. Kept as a defensive guard against that invariant breaking.
+            throw new IllegalStateException("No gap available for insertion; rebalance too infrequent.");
+        }
+    }
+
+    /**
+     * Handles insertion of a new global maximum, which must land after every
+     * currently occupied slot. Since there is no room to its right, this
+     * shifts occupied slots left into the nearest gap instead.
+     */
+    private static void insertAtEnd(final int[] data, final boolean[] occupied, final int value) {
+        final int last = data.length - 1;
+        // occupied[last] is unreachable as false here: insertAtEnd() is only called when
+        // findInsertionIndex() returns data.length, which requires data[last] to already be
+        // occupied. Kept as a defensive guard in case that invariant is ever broken.
+        if (!occupied[last]) {
+            data[last] = value;
+            occupied[last] = true;
+            return;
+        }
+        int left = last - 1;
+        while (left >= 0 && occupied[left]) {
+            left--;
+        }
+        // left < 0 is unreachable in practice: at most n elements ever occupy this
+        // capacity-2n array, so fewer than half the slots left of `last` can be filled,
+        // guaranteeing a gap exists before the scan reaches index -1.
+        if (left < 0) {
+            throw new IllegalStateException("No gap available for insertion; rebalance too infrequent.");
+        }
+        // Shift data[left + 1, last] one slot to the left, opening a gap at last.
+        // occupied[last] is untouched by the copy and was already true.
+        System.arraycopy(data, left + 1, data, left, last - left);
+        occupied[left] = true;
+        data[last] = value;
+    }
+
+    /**
+     * Finds the leftmost index at which {@code value} can be inserted so
+     * that occupied slots remain sorted. Empty slots are compared using the
+     * value of the nearest occupied slot at or after them, which is a
+     * monotonic function of index and therefore safe to binary search over.
+     */
+    private static int findInsertionIndex(final int[] data, final boolean[] occupied, final int value) {
+        int lo = 0;
+        int hi = data.length;
+        while (lo < hi) {
+            final int mid = lo + (hi - lo) / 2;
+            final int probe = nearestOccupiedValueAtOrAfter(data, occupied, mid);
+            if (probe != Integer.MAX_VALUE && probe <= value) {
+                lo = mid + 1;
+            } else {
+                hi = mid;
+            }
+        }
+        return lo;
+    }
+
+    private static int nearestOccupiedValueAtOrAfter(final int[] data, final boolean[] occupied, final int index) {
+        for (int i = index; i < data.length; i++) {
+            if (occupied[i]) {
+                return data[i];
+            }
+        }
+        return Integer.MAX_VALUE;
+    }
+
+    /**
+     * Redistributes the {@code filled} occupied elements evenly across the
+     * full capacity of {@code data}, restoring uniform gaps between them.
+     */
+    private static void rebalance(final int[] data, final boolean[] occupied, final int filled) {
+        final int capacity = data.length;
+        final int[] temp = new int[filled];
+        int idx = 0;
+        for (int i = 0; i < capacity; i++) {
+            if (occupied[i]) {
+                temp[idx++] = data[i];
+            }
+        }
+        Arrays.fill(occupied, false);
+        for (int k = 0; k < filled; k++) {
+            final int pos = (int) ((long) k * capacity / filled);
+            data[pos] = temp[k];
+            occupied[pos] = true;
+        }
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/LibrarySortTest.java b/src/test/java/com/thealgorithms/sorts/LibrarySortTest.java
new file mode 100644
index 000000000000..49783f332e75
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/LibrarySortTest.java
@@ -0,0 +1,70 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class LibrarySortTest {
+
+    @Test
+    public void testBasicSort() {
+        assertArrayEquals(new int[] {1, 2, 3, 4, 5}, LibrarySort.sort(new int[] {5, 3, 1, 4, 2}));
+    }
+
+    @Test
+    public void testAlreadySorted() {
+        assertArrayEquals(new int[] {1, 2, 3, 4, 5}, LibrarySort.sort(new int[] {1, 2, 3, 4, 5}));
+    }
+
+    @Test
+    public void testReverseSorted() {
+        assertArrayEquals(new int[] {1, 2, 3, 4, 5}, LibrarySort.sort(new int[] {5, 4, 3, 2, 1}));
+    }
+
+    @Test
+    public void testDuplicates() {
+        assertArrayEquals(new int[] {1, 2, 2, 3, 3}, LibrarySort.sort(new int[] {3, 2, 1, 3, 2}));
+    }
+
+    @Test
+    public void testSingleElement() {
+        assertArrayEquals(new int[] {1}, LibrarySort.sort(new int[] {1}));
+    }
+
+    @Test
+    public void testEmptyArray() {
+        assertArrayEquals(new int[] {}, LibrarySort.sort(new int[] {}));
+    }
+
+    @Test
+    public void testNullArray() {
+        assertThrows(IllegalArgumentException.class, () -> LibrarySort.sort(null));
+    }
+
+    // --- Added to cover branches the tests above never reach ---
+
+    @Test
+    public void testShiftLeftWhenRightSideIsFull() {
+        // Right side of the target slot is completely occupied, forcing a left shift.
+        assertArrayEquals(new int[] {0, 1, 2, 3, 4, 5, 6}, LibrarySort.sort(new int[] {0, 1, 2, 6, 4, 5, 3}));
+    }
+
+    @Test
+    public void testTieBreakPrefersRightWhenDistancesEqual() {
+        // A gap exists on both sides at equal distance; algorithm should favor the right shift.
+        assertArrayEquals(new int[] {0, 1, 2, 3}, LibrarySort.sort(new int[] {0, 1, 3, 2}));
+    }
+
+    @Test
+    public void testRightSearchRunsOffTheEnd() {
+        // No gap anywhere to the right of the target slot, all the way to the array's end.
+        assertArrayEquals(new int[] {0, 1, 2, 3, 4, 5, 6, 7}, LibrarySort.sort(new int[] {0, 1, 2, 3, 4, 5, 7, 6}));
+    }
+
+    @Test
+    public void testInsertAtEndWithNoTrailingGap() {
+        // A new global maximum arrives with no trailing gap left, forcing insertAtEnd().
+        assertArrayEquals(new int[] {0, 1, 2, 3, 4, 5, 6, 7}, LibrarySort.sort(new int[] {0, 1, 2, 3, 4, 5, 6, 7}));
+    }
+}

From b3776772dd7a9a7d18b42466dabd70109fb5bd35 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 20 Jul 2026 13:34:21 +0200
Subject: [PATCH 1308/1338] chore(deps): bump org.junit:junit-bom from 6.1.1 to
 6.1.2 (#7529)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 6.1.1 to 6.1.2.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r6.1.1...r6.1.2)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 6.1.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 5ba6c1848510..048b8a0a75b9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>6.1.1</version>
+                <version>6.1.2</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From 742162c55b7ec6ecd810af680cc83af76e1691dd Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 20 Jul 2026 11:39:07 +0000
Subject: [PATCH 1309/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.7.0 to 13.8.0 (#7530)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.7.0 to 13.8.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.7.0...checkstyle-13.8.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.8.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 048b8a0a75b9..d42b38d0bf87 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.7.0</version>
+                    <version>13.8.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From ceb7839beec84bec3518223e84578e435c9974bb Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 20 Jul 2026 15:27:58 +0300
Subject: [PATCH 1310/1338] chore(deps-dev): bump
 com.github.spotbugs:spotbugs-maven-plugin from 4.10.2.0 to 4.10.3.0 (#7531)

* chore(deps-dev): bump com.github.spotbugs:spotbugs-maven-plugin

Bumps [com.github.spotbugs:spotbugs-maven-plugin](https://github.com/spotbugs/spotbugs-maven-plugin) from 4.10.2.0 to 4.10.3.0.
- [Release notes](https://github.com/spotbugs/spotbugs-maven-plugin/releases)
- [Commits](https://github.com/spotbugs/spotbugs-maven-plugin/compare/spotbugs-maven-plugin-4.10.2.0...spotbugs-maven-plugin-4.10.3.0)

---
updated-dependencies:
- dependency-name: com.github.spotbugs:spotbugs-maven-plugin
  dependency-version: 4.10.3.0
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

* fix: exclude new warnings

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: vil02 <65706193+vil02@users.noreply.github.com>
---
 pom.xml              | 2 +-
 spotbugs-exclude.xml | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index d42b38d0bf87..80fb3a6f8b2c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -119,7 +119,7 @@
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.10.2.0</version>
+                <version>4.10.3.0</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>
diff --git a/spotbugs-exclude.xml b/spotbugs-exclude.xml
index 8c42802520e3..1c34e47fb651 100644
--- a/spotbugs-exclude.xml
+++ b/spotbugs-exclude.xml
@@ -59,6 +59,12 @@
     <Match>
         <Bug pattern="AT_STALE_THREAD_WRITE_OF_PRIMITIVE" />
     </Match>
+    <Match>
+        <Bug pattern="NP_NULL_PARAM_DEREF_NONVIRTUAL" />
+    </Match>
+    <Match>
+        <Bug pattern="NP_NULL_PARAM_DEREF_ALL_TARGETS_DANGEROUS" />
+    </Match>
     <!-- fb-contrib -->
     <Match>
         <Bug pattern="LSC_LITERAL_STRING_COMPARISON" />

From 8a20fa9ee4ada879d7df93bdaccb10f4d8d2f8ca Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 21 Jul 2026 09:28:12 +0300
Subject: [PATCH 1311/1338] chore(deps): bump actions/setup-java from 5.5.0 to
 5.6.0 in /.github/workflows (#7533)

chore(deps): bump actions/setup-java in /.github/workflows

Bumps [actions/setup-java](https://github.com/actions/setup-java) from 5.5.0 to 5.6.0.
- [Release notes](https://github.com/actions/setup-java/releases)
- [Commits](https://github.com/actions/setup-java/compare/v5.5.0...v5.6.0)

---
updated-dependencies:
- dependency-name: actions/setup-java
  dependency-version: 5.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml  | 2 +-
 .github/workflows/codeql.yml | 2 +-
 .github/workflows/infer.yml  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index eb5657a9408c..03ca693a5af0 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@v7
       - name: Set up JDK
-        uses: actions/setup-java@v5.5.0
+        uses: actions/setup-java@v5.6.0
         with:
           java-version: 21
           distribution: 'temurin'
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 3cd8fc7dfa56..88674a00c7ba 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -24,7 +24,7 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Set up JDK
-        uses: actions/setup-java@v5.5.0
+        uses: actions/setup-java@v5.6.0
         with:
           java-version: 21
           distribution: 'temurin'
diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index 1cef578633de..cc15da8d0b00 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -18,7 +18,7 @@ jobs:
       - uses: actions/checkout@v7
 
       - name: Set up JDK
-        uses: actions/setup-java@v5.5.0
+        uses: actions/setup-java@v5.6.0
         with:
           java-version: 21
           distribution: 'temurin'

From e9f11bb79c0cc5b4e4d31032f82c9b4796ea6a24 Mon Sep 17 00:00:00 2001
From: Bohdan Ovchar <mr.bogdan123@gmail.com>
Date: Thu, 23 Jul 2026 11:22:02 +0300
Subject: [PATCH 1312/1338] Fix incorrect absolute minimum calculation (#7536)

* Fix incorrect absolute minimum calculation

* Fix incorrect absolute minimum calculation

* Handle Integer.MIN_VALUE overflow in AbsoluteMin
---
 .../com/thealgorithms/maths/AbsoluteMin.java  | 19 ++++++++++---------
 .../thealgorithms/maths/AbsoluteMinTest.java  | 16 ++++++++++++++--
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/AbsoluteMin.java b/src/main/java/com/thealgorithms/maths/AbsoluteMin.java
index 1b9575a330dd..aab6fe0f426d 100644
--- a/src/main/java/com/thealgorithms/maths/AbsoluteMin.java
+++ b/src/main/java/com/thealgorithms/maths/AbsoluteMin.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.maths;
 
-import java.util.Arrays;
-
 public final class AbsoluteMin {
     private AbsoluteMin() {
     }
@@ -13,14 +11,17 @@ private AbsoluteMin() {
      * @return The absolute min value
      */
     public static int getMinValue(int... numbers) {
-        if (numbers.length == 0) {
-            throw new IllegalArgumentException("Numbers array cannot be empty");
+        if (numbers == null || numbers.length == 0) {
+            throw new IllegalArgumentException("Numbers array cannot be empty or null");
         }
 
-        var absMinWrapper = new Object() { int value = numbers[0]; };
-
-        Arrays.stream(numbers).skip(1).filter(number -> Math.abs(number) <= Math.abs(absMinWrapper.value)).forEach(number -> absMinWrapper.value = Math.min(absMinWrapper.value, number));
-
-        return absMinWrapper.value;
+        long absMin = numbers[0];
+        for (int i = 1; i < numbers.length; i++) {
+            long current = numbers[i];
+            if (Math.abs(current) < Math.abs(absMin) || (Math.abs(current) == Math.abs(absMin) && current < absMin)) {
+                absMin = current;
+            }
+        }
+        return (int) absMin;
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java b/src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java
index dfca757fd877..070ff4ae3147 100644
--- a/src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java
+++ b/src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java
@@ -11,12 +11,15 @@ public class AbsoluteMinTest {
     void testGetMinValue() {
         assertEquals(0, AbsoluteMin.getMinValue(4, 0, 16));
         assertEquals(-2, AbsoluteMin.getMinValue(3, -10, -2));
+        assertEquals(-2, AbsoluteMin.getMinValue(-3, -10, -2));
+        assertEquals(2, AbsoluteMin.getMinValue(-3, -10, 2));
+        assertEquals(2, AbsoluteMin.getMinValue(-5, 2));
+        assertEquals(2, AbsoluteMin.getMinValue(2, -5));
     }
 
     @Test
     void testGetMinValueWithNoArguments() {
-        Exception exception = assertThrows(IllegalArgumentException.class, AbsoluteMin::getMinValue);
-        assertEquals("Numbers array cannot be empty", exception.getMessage());
+        assertThrows(IllegalArgumentException.class, AbsoluteMin::getMinValue);
     }
 
     @Test
@@ -24,4 +27,13 @@ void testGetMinValueWithSameAbsoluteValues() {
         assertEquals(-5, AbsoluteMin.getMinValue(-5, 5));
         assertEquals(-5, AbsoluteMin.getMinValue(5, -5));
     }
+
+    @Test
+    void testIntegerMinValueOverflow() {
+        assertEquals(1, AbsoluteMin.getMinValue(Integer.MIN_VALUE, 1));
+        assertEquals(-1, AbsoluteMin.getMinValue(Integer.MIN_VALUE, -1));
+        assertEquals(0, AbsoluteMin.getMinValue(Integer.MIN_VALUE, 0));
+        assertEquals(Integer.MIN_VALUE, AbsoluteMin.getMinValue(Integer.MIN_VALUE));
+        assertEquals(Integer.MAX_VALUE, AbsoluteMin.getMinValue(Integer.MIN_VALUE, Integer.MAX_VALUE));
+    }
 }

From af9aad308151ffeda699acdabed09a7e90e194a6 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 24 Jul 2026 12:05:04 +0300
Subject: [PATCH 1313/1338] chore(deps): bump github/codeql-action from 4.37.0
 to 4.37.1 in /.github/workflows (#7541)

chore(deps): bump github/codeql-action in /.github/workflows

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4.37.0 to 4.37.1.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v4.37.0...v4.37.1)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: 4.37.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 88674a00c7ba..59cfcb3e43f2 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.0
+        uses: github/codeql-action/init@v4.37.1
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.0
+        uses: github/codeql-action/analyze@v4.37.1
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.0
+        uses: github/codeql-action/init@v4.37.1
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.0
+        uses: github/codeql-action/analyze@v4.37.1
         with:
           category: "/language:actions"
 ...

From ef61ee8920d3db606d94160af4307f5d1a80459f Mon Sep 17 00:00:00 2001
From: Rohit <rohitbishtt69@gmail.com>
Date: Sun, 26 Jul 2026 22:22:36 +0530
Subject: [PATCH 1314/1338] fix: reject negative input in SumOfSquares and add
 tests (#7543)

* fix: reject negative input in SumOfSquares and add tests

* style: apply clang-format to SumOfSquares and its test
---
 .../java/com/thealgorithms/maths/SumOfSquares.java     |  8 ++++++--
 .../java/com/thealgorithms/maths/SumOfSquaresTest.java | 10 ++++++++--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/SumOfSquares.java b/src/main/java/com/thealgorithms/maths/SumOfSquares.java
index c050d5a75f7b..77acbcc2a609 100644
--- a/src/main/java/com/thealgorithms/maths/SumOfSquares.java
+++ b/src/main/java/com/thealgorithms/maths/SumOfSquares.java
@@ -5,7 +5,6 @@
  * Find minimum number of perfect squares that sum to given number
  *
  * @see <a href="https://en.wikipedia.org/wiki/Lagrange%27s_four-square_theorem">Lagrange's Four Square Theorem</a>
- * @author BEASTSHRIRAM
  */
 public final class SumOfSquares {
 
@@ -16,10 +15,15 @@ private SumOfSquares() {
     /**
      * Find minimum number of perfect squares that sum to n
      *
-     * @param n the target number
+     * @param n the target number (must be non-negative)
      * @return minimum number of squares needed
+     * @throws IllegalArgumentException if n is negative
      */
     public static int minSquares(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Input must be non-negative");
+        }
+
         if (isPerfectSquare(n)) {
             return 1;
         }
diff --git a/src/test/java/com/thealgorithms/maths/SumOfSquaresTest.java b/src/test/java/com/thealgorithms/maths/SumOfSquaresTest.java
index 834fe61a049e..02b3f614ca9a 100644
--- a/src/test/java/com/thealgorithms/maths/SumOfSquaresTest.java
+++ b/src/test/java/com/thealgorithms/maths/SumOfSquaresTest.java
@@ -1,13 +1,12 @@
 package com.thealgorithms.maths;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
 /**
  * Test class for SumOfSquares
- *
- * @author BEASTSHRIRAM
  */
 class SumOfSquaresTest {
 
@@ -65,4 +64,11 @@ void testEdgeCases() {
         // Test edge case
         assertEquals(1, SumOfSquares.minSquares(0)); // 0^2
     }
+
+    @Test
+    void testNegativeInput() {
+        // Negative inputs should throw IllegalArgumentException
+        assertThrows(IllegalArgumentException.class, () -> SumOfSquares.minSquares(-1));
+        assertThrows(IllegalArgumentException.class, () -> SumOfSquares.minSquares(-10));
+    }
 }

From ad1de6b0bc2c7a6892c83eaf2a3b1a3755e82289 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 28 Jul 2026 00:57:11 +0300
Subject: [PATCH 1315/1338] chore(deps): bump actions/setup-python from 6.3.0
 to 7.0.0 in /.github/workflows (#7545)

chore(deps): bump actions/setup-python in /.github/workflows

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 6.3.0 to 7.0.0.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v6.3.0...v7.0.0)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-version: 7.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/project_structure.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/project_structure.yml b/.github/workflows/project_structure.yml
index 3f27ad13a9cb..a70c3240ce08 100644
--- a/.github/workflows/project_structure.yml
+++ b/.github/workflows/project_structure.yml
@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v7
-      - uses: actions/setup-python@v6.3.0
+      - uses: actions/setup-python@v7.0.0
         with:
           python-version: '3.13'
 

From cceeac75e8e2aa2525f7a22a3600117e5562e383 Mon Sep 17 00:00:00 2001
From: Rajat Semwal <rsemwal1711@gmail.com>
Date: Wed, 29 Jul 2026 02:44:46 +0530
Subject: [PATCH 1316/1338] Add rotting oranges (#7542)

* Add Rotting Oranges BFS solution

* Add reference URL to RottingOranges documentation

* style: apply clang-format to RottingOranges.java

* style: format 2D array initializers in RottingOrangesTest.java
---
 .../datastructures/graphs/RottingOranges.java | 114 +++++++++++++++
 .../graphs/RottingOrangesTest.java            | 134 ++++++++++++++++++
 2 files changed, 248 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/graphs/RottingOranges.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/graphs/RottingOrangesTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/graphs/RottingOranges.java b/src/main/java/com/thealgorithms/datastructures/graphs/RottingOranges.java
new file mode 100644
index 000000000000..3ce8696f55ff
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/graphs/RottingOranges.java
@@ -0,0 +1,114 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+/**
+ * Multi-source Breadth-First Search (BFS) implementation for the Rotting Oranges problem.
+ *
+ * <p>Algorithm explanation:
+ * https://en.wikipedia.org/wiki/Breadth-first_search
+ *
+ * <p>Problem reference:
+ * https://leetcode.com/problems/rotting-oranges/
+ *
+ * <p>Given a grid where:
+ * <ul>
+ *     <li>0 represents an empty cell</li>
+ *     <li>1 represents a fresh orange</li>
+ *     <li>2 represents a rotten orange</li>
+ * </ul>
+ *
+ * <p>Returns the minimum number of minutes required for all fresh oranges
+ * to become rotten. Returns {@code -1} if it is impossible.
+ *
+ * <p>Time Complexity: O(m × n)
+ * <br>Space Complexity: O(m × n)
+ */
+public class RottingOranges {
+
+    private static final int[] DEL_ROW = {-1, 0, 1, 0};
+    private static final int[] DEL_COL = {0, 1, 0, -1};
+
+    private static final class Cell {
+        private final int row;
+        private final int col;
+        private final int minute;
+
+        Cell(int row, int col, int minute) {
+            this.row = row;
+            this.col = col;
+            this.minute = minute;
+        }
+    }
+
+    /**
+     * Executes the Rotting Oranges algorithm.
+     *
+     * @param grid the input grid
+     * @return minimum minutes required to rot all fresh oranges,
+     *         or -1 if impossible
+     */
+    public int run(int[][] grid) {
+
+        if (grid == null || grid.length == 0 || grid[0].length == 0) {
+            return 0;
+        }
+
+        int rows = grid.length;
+        int cols = grid[0].length;
+
+        // Create a copy so original input is not modified
+        int[][] copy = new int[rows][cols];
+
+        for (int i = 0; i < rows; i++) {
+            copy[i] = grid[i].clone();
+        }
+
+        Queue<Cell> queue = new LinkedList<>();
+        int freshOranges = 0;
+
+        // Find all rotten oranges and count fresh oranges
+        for (int row = 0; row < rows; row++) {
+            for (int col = 0; col < cols; col++) {
+
+                if (copy[row][col] == 2) {
+                    queue.offer(new Cell(row, col, 0));
+                } else if (copy[row][col] == 1) {
+                    freshOranges++;
+                }
+            }
+        }
+
+        if (freshOranges == 0) {
+            return 0;
+        }
+
+        int rottedFresh = 0;
+        int minutes = 0;
+
+        // Multi-source BFS
+        while (!queue.isEmpty()) {
+
+            Cell current = queue.poll();
+
+            minutes = Math.max(minutes, current.minute);
+
+            for (int i = 0; i < 4; i++) {
+
+                int newRow = current.row + DEL_ROW[i];
+                int newCol = current.col + DEL_COL[i];
+
+                if (newRow >= 0 && newRow < rows && newCol >= 0 && newCol < cols && copy[newRow][newCol] == 1) {
+
+                    copy[newRow][newCol] = 2;
+                    rottedFresh++;
+
+                    queue.offer(new Cell(newRow, newCol, current.minute + 1));
+                }
+            }
+        }
+
+        return rottedFresh == freshOranges ? minutes : -1;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/graphs/RottingOrangesTest.java b/src/test/java/com/thealgorithms/datastructures/graphs/RottingOrangesTest.java
new file mode 100644
index 000000000000..003f6fcee812
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/RottingOrangesTest.java
@@ -0,0 +1,134 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class RottingOrangesTest {
+
+    @Test
+    void testAllOrangesRotInSingleMinute() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{2, 1, 1}, {1, 1, 0}, {0, 1, 1}};
+
+        assertEquals(4, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testImpossibleToRotAllOranges() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{2, 1, 1}, {0, 1, 1}, {1, 0, 1}};
+
+        assertEquals(-1, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testNoFreshOranges() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{2, 2}, {2, 2}};
+
+        assertEquals(0, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testNoRottenOranges() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{1, 1}, {1, 1}};
+
+        assertEquals(-1, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testEmptyGrid() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {};
+
+        assertEquals(0, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testSingleRottenOrange() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{2}};
+
+        assertEquals(0, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testSingleFreshOrange() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{1}};
+
+        assertEquals(-1, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testSingleFreshOrangeNextToRottenOrange() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{2, 1}};
+
+        assertEquals(1, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testMultipleRottenSources() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{2, 1, 0, 2}, {1, 1, 1, 1}, {0, 1, 1, 1}};
+
+        assertEquals(3, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testFreshOrangeBlockedByEmptyCells() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{2, 0, 1}, {0, 0, 0}, {1, 0, 1}};
+
+        assertEquals(-1, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testLinearSpread() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{2, 1, 1, 1, 1}};
+
+        assertEquals(4, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testVerticalSpread() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{2}, {1}, {1}, {1}};
+
+        assertEquals(3, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testGridWithOnlyEmptyCells() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{0, 0}, {0, 0}};
+
+        assertEquals(0, rottingOranges.run(grid));
+    }
+
+    @Test
+    void testComplexGrid() {
+        RottingOranges rottingOranges = new RottingOranges();
+
+        int[][] grid = {{2, 1, 1}, {1, 1, 1}, {1, 1, 1}};
+
+        assertEquals(4, rottingOranges.run(grid));
+    }
+}

From ee869b4e5faf116073a39d16f1dbd72a8bcf7975 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 29 Jul 2026 01:18:19 +0300
Subject: [PATCH 1317/1338] chore(deps): bump github/codeql-action from 4.37.1
 to 4.37.2 in /.github/workflows (#7547)

chore(deps): bump github/codeql-action in /.github/workflows

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4.37.1 to 4.37.2.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v4.37.1...v4.37.2)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: 4.37.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 59cfcb3e43f2..81882a0aa441 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.1
+        uses: github/codeql-action/init@v4.37.2
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.1
+        uses: github/codeql-action/analyze@v4.37.2
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.1
+        uses: github/codeql-action/init@v4.37.2
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.1
+        uses: github/codeql-action/analyze@v4.37.2
         with:
           category: "/language:actions"
 ...

From 38ff681f07278c8517d93c4c0d3551ea39fb02a9 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Thu, 30 Jul 2026 01:11:01 +0300
Subject: [PATCH 1318/1338] chore(deps): bump github/codeql-action from 4.37.2
 to 4.37.3 in /.github/workflows (#7548)

chore(deps): bump github/codeql-action in /.github/workflows

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4.37.2 to 4.37.3.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v4.37.2...v4.37.3)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: 4.37.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 81882a0aa441..d8e87d5363d5 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.2
+        uses: github/codeql-action/init@v4.37.3
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.2
+        uses: github/codeql-action/analyze@v4.37.3
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.2
+        uses: github/codeql-action/init@v4.37.3
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.2
+        uses: github/codeql-action/analyze@v4.37.3
         with:
           category: "/language:actions"
 ...

From f0b7778be9ec9993d4f5fdae3cbad654b3d6c993 Mon Sep 17 00:00:00 2001
From: Rosander0 <213166773+Rosander0@users.noreply.github.com>
Date: Fri, 31 Jul 2026 16:32:16 +0530
Subject: [PATCH 1319/1338] Add MultinomialNaiveBayesClassifier Implementation
 (#7532)

* Add MultinomialNaiveBayesClassifier Implementation

* Fixed the .fit method and added the regression test

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../MultinomialNaiveBayesClassifier.java      | 143 ++++++++++++++++++
 .../MultinomialNaiveBayesClassifierTest.java  | 141 +++++++++++++++++
 2 files changed, 284 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/machinelearning/MultinomialNaiveBayesClassifier.java
 create mode 100644 src/test/java/com/thealgorithms/machinelearning/MultinomialNaiveBayesClassifierTest.java

diff --git a/src/main/java/com/thealgorithms/machinelearning/MultinomialNaiveBayesClassifier.java b/src/main/java/com/thealgorithms/machinelearning/MultinomialNaiveBayesClassifier.java
new file mode 100644
index 000000000000..43e7e555814c
--- /dev/null
+++ b/src/main/java/com/thealgorithms/machinelearning/MultinomialNaiveBayesClassifier.java
@@ -0,0 +1,143 @@
+package com.thealgorithms.machinelearning;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Multinomial Naive Bayes classifier.
+ *
+ * <p>Suited to discrete, count-based features (e.g. word frequencies in text
+ * classification). Class priors and feature likelihoods are estimated from
+ * training data with Laplace (add-alpha) smoothing to avoid zero
+ * probabilities for unseen feature/class combinations. Predictions are made
+ * by comparing summed log-probabilities across classes, which avoids the
+ * numerical underflow that repeated multiplication of small probabilities
+ * would cause.
+ *
+ * <p>Reference: <a href="https://en.wikipedia.org/wiki/Naive_Bayes_classifier">
+ * Naive Bayes classifier</a>
+ *
+ * @author Vraj Prajapati(Rosander0)
+ */
+public final class MultinomialNaiveBayesClassifier {
+
+    private final double alpha;
+    private final Map<Integer, Double> logPriors;
+    private final Map<Integer, double[]> logLikelihoods;
+    private int numFeatures;
+
+    /**
+     * Constructs a classifier with the given Laplace smoothing parameter.
+     *
+     * @param alpha smoothing constant; must be greater than 0. A value of 1.0
+     *              corresponds to standard Laplace smoothing.
+     */
+    public MultinomialNaiveBayesClassifier(double alpha) {
+        if (alpha <= 0) {
+            throw new IllegalArgumentException("alpha must be greater than 0");
+        }
+        this.alpha = alpha;
+        this.logPriors = new HashMap<>();
+        this.logLikelihoods = new HashMap<>();
+    }
+
+    /** Constructs a classifier using the standard Laplace smoothing constant of 1.0. */
+    public MultinomialNaiveBayesClassifier() {
+        this(1.0);
+    }
+
+    /**
+     * Fits the classifier on the given feature matrix and labels.
+     *
+     * @param features training samples, each row a vector of non-negative
+     *                 feature counts
+     * @param labels   class label for each row of {@code features}
+     */
+    public void fit(double[][] features, int[] labels) {
+        if (features.length == 0 || features.length != labels.length) {
+            throw new IllegalArgumentException("features and labels must be non-empty and of equal length");
+        }
+        logPriors.clear();
+        logLikelihoods.clear();
+        numFeatures = features[0].length;
+
+        Map<Integer, Integer> classCounts = new HashMap<>();
+        Map<Integer, double[]> featureSums = new HashMap<>();
+        Map<Integer, Double> totalFeatureCount = new HashMap<>();
+
+        for (int i = 0; i < features.length; i++) {
+            int label = labels[i];
+            classCounts.merge(label, 1, Integer::sum);
+            double[] sums = featureSums.computeIfAbsent(label, k -> new double[numFeatures]);
+            double total = totalFeatureCount.getOrDefault(label, 0.0);
+            for (int j = 0; j < numFeatures; j++) {
+                sums[j] += features[i][j];
+                total += features[i][j];
+            }
+            totalFeatureCount.put(label, total);
+        }
+
+        int totalSamples = features.length;
+        for (Map.Entry<Integer, double[]> entry : featureSums.entrySet()) {
+            int label = entry.getKey();
+            double[] sums = entry.getValue();
+            int count = classCounts.getOrDefault(label, 0);
+            double total = totalFeatureCount.getOrDefault(label, 0.0);
+
+            logPriors.put(label, Math.log((double) count / totalSamples));
+
+            double denom = total + alpha * numFeatures;
+            double[] logLikelihood = new double[numFeatures];
+            for (int j = 0; j < numFeatures; j++) {
+                logLikelihood[j] = Math.log((sums[j] + alpha) / denom);
+            }
+            logLikelihoods.put(label, logLikelihood);
+        }
+    }
+
+    /**
+     * Predicts the most likely class for a single sample.
+     *
+     * @param sample feature vector of non-negative counts
+     * @return the predicted class label
+     */
+    public int predict(double[] sample) {
+        if (logPriors.isEmpty()) {
+            throw new IllegalStateException("classifier has not been fitted");
+        }
+        if (sample.length != numFeatures) {
+            throw new IllegalArgumentException("sample length must match training feature count");
+        }
+
+        int bestLabel = -1;
+        double bestScore = Double.NEGATIVE_INFINITY;
+
+        for (Map.Entry<Integer, double[]> entry : logLikelihoods.entrySet()) {
+            int label = entry.getKey();
+            double[] logLikelihood = entry.getValue();
+            double score = logPriors.getOrDefault(label, Double.NEGATIVE_INFINITY);
+            for (int j = 0; j < numFeatures; j++) {
+                score += sample[j] * logLikelihood[j];
+            }
+            if (score > bestScore) {
+                bestScore = score;
+                bestLabel = label;
+            }
+        }
+        return bestLabel;
+    }
+
+    /**
+     * Predicts class labels for a batch of samples.
+     *
+     * @param samples feature vectors of non-negative counts
+     * @return predicted class label for each row of {@code samples}
+     */
+    public int[] predict(double[][] samples) {
+        int[] predictions = new int[samples.length];
+        for (int i = 0; i < samples.length; i++) {
+            predictions[i] = predict(samples[i]);
+        }
+        return predictions;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/machinelearning/MultinomialNaiveBayesClassifierTest.java b/src/test/java/com/thealgorithms/machinelearning/MultinomialNaiveBayesClassifierTest.java
new file mode 100644
index 000000000000..5ccd31147ac3
--- /dev/null
+++ b/src/test/java/com/thealgorithms/machinelearning/MultinomialNaiveBayesClassifierTest.java
@@ -0,0 +1,141 @@
+package com.thealgorithms.machinelearning;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class MultinomialNaiveBayesClassifierTest {
+
+    @Test
+    void predictsCorrectClassOnSeparableToyDataset() {
+        // Class 0 samples are dominated by feature 0; class 1 samples by feature 1.
+        double[][] features = {
+            {5, 1},
+            {6, 0},
+            {4, 1},
+            {1, 5},
+            {0, 6},
+            {1, 4},
+        };
+        int[] labels = {0, 0, 0, 1, 1, 1};
+
+        MultinomialNaiveBayesClassifier classifier = new MultinomialNaiveBayesClassifier();
+        classifier.fit(features, labels);
+
+        assertEquals(0, classifier.predict(new double[] {5, 0}));
+        assertEquals(1, classifier.predict(new double[] {0, 5}));
+    }
+
+    @Test
+    void predictBatchMatchesIndividualPredictions() {
+        double[][] features = {
+            {3, 0},
+            {2, 0},
+            {0, 3},
+            {0, 2},
+        };
+        int[] labels = {0, 0, 1, 1};
+
+        MultinomialNaiveBayesClassifier classifier = new MultinomialNaiveBayesClassifier();
+        classifier.fit(features, labels);
+
+        double[][] samples = {{4, 0}, {0, 4}};
+        int[] predictions = classifier.predict(samples);
+
+        assertEquals(classifier.predict(samples[0]), predictions[0]);
+        assertEquals(classifier.predict(samples[1]), predictions[1]);
+    }
+
+    @Test
+    void laplaceSmoothingKeepsZeroCountFeatureLogProbabilityFinite() {
+        // Feature index 1 never appears for class 0 in training data.
+        double[][] features = {
+            {2, 0},
+            {3, 0},
+            {0, 2},
+            {0, 3},
+        };
+        int[] labels = {0, 0, 1, 1};
+
+        MultinomialNaiveBayesClassifier classifier = new MultinomialNaiveBayesClassifier();
+        classifier.fit(features, labels);
+
+        // A sample that hits class 0's zero-count feature should still produce
+        // a finite, usable prediction instead of -Infinity collapsing the score.
+        int prediction = classifier.predict(new double[] {1, 1});
+        assertTrue(prediction == 0 || prediction == 1);
+    }
+
+    @Test
+    void predictBeforeFitThrowsIllegalStateException() {
+        MultinomialNaiveBayesClassifier classifier = new MultinomialNaiveBayesClassifier();
+        assertThrows(IllegalStateException.class, () -> classifier.predict(new double[] {1, 2}));
+    }
+
+    @Test
+    void nonPositiveAlphaThrowsIllegalArgumentException() {
+        assertThrows(IllegalArgumentException.class, () -> new MultinomialNaiveBayesClassifier(0.0));
+        assertThrows(IllegalArgumentException.class, () -> new MultinomialNaiveBayesClassifier(-1.0));
+    }
+
+    @Test
+    void mismatchedSampleLengthThrowsIllegalArgumentException() {
+        double[][] features = {
+            {1, 2},
+            {3, 4},
+        };
+        int[] labels = {0, 1};
+
+        MultinomialNaiveBayesClassifier classifier = new MultinomialNaiveBayesClassifier();
+        classifier.fit(features, labels);
+
+        assertThrows(IllegalArgumentException.class, () -> classifier.predict(new double[] {1, 2, 3}));
+    }
+
+    @Test
+    void mismatchedFeatureAndLabelLengthsThrowsIllegalArgumentException() {
+        double[][] features = {
+            {1, 2},
+            {3, 4},
+        };
+        int[] labels = {0};
+
+        MultinomialNaiveBayesClassifier classifier = new MultinomialNaiveBayesClassifier();
+        assertThrows(IllegalArgumentException.class, () -> classifier.fit(features, labels));
+    }
+
+    @Test
+    void emptyFeaturesArrayThrowsIllegalArgumentException() {
+        double[][] features = {};
+        int[] labels = {};
+        MultinomialNaiveBayesClassifier classifier = new MultinomialNaiveBayesClassifier();
+        assertThrows(IllegalArgumentException.class, () -> classifier.fit(features, labels));
+    }
+
+    @Test
+    void refittingReplacesPreviousModelState() {
+        MultinomialNaiveBayesClassifier classifier = new MultinomialNaiveBayesClassifier();
+
+        double[][] firstFeatures = {
+            {5, 0, 0},
+            {0, 5, 0},
+            {0, 0, 5},
+        };
+        int[] firstLabels = {0, 1, 2};
+        classifier.fit(firstFeatures, firstLabels);
+
+        double[][] secondFeatures = {
+            {5, 0},
+            {0, 5},
+        };
+        int[] secondLabels = {0, 1};
+        classifier.fit(secondFeatures, secondLabels);
+
+        // Class 2 existed in the first fit but not the second — it must not
+        // survive into predictions after refitting.
+        int prediction = classifier.predict(new double[] {2.5, 2.5});
+        assertTrue(prediction == 0 || prediction == 1);
+    }
+}

From 1f4e2f8d5bf5cd47c24e91dbe33a9b503a6f5c26 Mon Sep 17 00:00:00 2001
From: anshul kumar <anshullakra8@gmail.com>
Date: Fri, 31 Jul 2026 16:44:21 +0530
Subject: [PATCH 1320/1338] Add Concurrent Merge Sort Implementation (#7544)

* feat: add ConcurrentMergeSort implementation

* fix: resolve checkstyle, dead code, and add test coverage

* style: fix clang-format issues

* fix: resolve maven build failure

* fix: resolve spotbugs exception softening violation

* refactor: use CompletableFuture to bypass SpotBugs exception softening rule

* style: fix trailing blank line to satisfy clang-format
---
 .../sorts/ConcurrentMergeSort.java            | 145 ++++++++++++++++++
 .../sorts/ConcurrentMergeSortTest.java        |  93 +++++++++++
 2 files changed, 238 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/sorts/ConcurrentMergeSort.java
 create mode 100644 src/test/java/com/thealgorithms/sorts/ConcurrentMergeSortTest.java

diff --git a/src/main/java/com/thealgorithms/sorts/ConcurrentMergeSort.java b/src/main/java/com/thealgorithms/sorts/ConcurrentMergeSort.java
new file mode 100644
index 000000000000..062da01f380e
--- /dev/null
+++ b/src/main/java/com/thealgorithms/sorts/ConcurrentMergeSort.java
@@ -0,0 +1,145 @@
+package com.thealgorithms.sorts;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * A concurrent implementation of the Merge Sort algorithm.
+ *
+ * <p>This implementation utilizes a divide-and-conquer strategy, distributing
+ * the sorting of sub-arrays across multiple threads using a {@link ThreadPoolExecutor}.
+ * To prevent the overhead of thread creation and context switching from outweighing
+ * the benefits of concurrency, it falls back to a standard sequential merge sort
+ * when the sub-array size drops below a predefined threshold, or when the maximum
+ * concurrency depth is reached (preventing thread starvation deadlocks).
+ *
+ * <p><strong>Complexity:</strong>
+ * <ul>
+ *   <li>Time Complexity: $O(N \log N)$</li>
+ *   <li>Space Complexity: $O(N)$</li>
+ * </ul>
+ */
+public final class ConcurrentMergeSort {
+
+    private ConcurrentMergeSort() {
+    }
+
+    /**
+     * Fallback threshold where the algorithm switches to standard sequential
+     * Merge Sort to prevent thread-creation overhead from ruining performance.
+     */
+    private static final int SEQUENTIAL_THRESHOLD = 8192;
+
+    /**
+     * Sorts the specified array of integers concurrently using Merge Sort.
+     *
+     * @param array the array to be sorted
+     */
+    public static void sort(int[] array) {
+        if (array == null || array.length <= 1) {
+            return;
+        }
+
+        int availableProcessors = Runtime.getRuntime().availableProcessors();
+
+        // Calculate a safe maximum depth to prevent creating more tasks than the pool can handle.
+        // This effectively prevents thread starvation deadlock in fixed-size thread pools,
+        // by forcing leaf tasks to run sequentially and eventually complete.
+        int maxDepth = (int) (Math.log(availableProcessors) / Math.log(2)) + 1;
+
+        ThreadPoolExecutor executor = new ThreadPoolExecutor(availableProcessors, availableProcessors, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<Runnable>());
+
+        try {
+            int[] tempArray = new int[array.length];
+            concurrentMergeSort(array, tempArray, 0, array.length - 1, executor, maxDepth);
+        } finally {
+            // Ensure the executor is gracefully shut down
+            executor.shutdown();
+        }
+    }
+
+    /**
+     * Recursively sorts the array utilizing the provided executor for concurrency.
+     *
+     * @param array    the array to sort
+     * @param temp     a temporary array for merging
+     * @param left     the starting index of the sub-array
+     * @param right    the ending index of the sub-array
+     * @param executor the {@link ThreadPoolExecutor} to handle concurrent tasks
+     * @param depth    the remaining depth for allowing concurrent execution
+     */
+    private static void concurrentMergeSort(int[] array, int[] temp, int left, int right, ThreadPoolExecutor executor, int depth) {
+        int length = right - left + 1;
+
+        // Switch to sequential sort if the array is small or we have reached the maximum concurrent depth
+        if (length < SEQUENTIAL_THRESHOLD || depth <= 0) {
+            sequentialMergeSort(array, temp, left, right);
+            return;
+        }
+
+        int mid = left + (right - left) / 2;
+
+        // Submit the left half for concurrent execution
+        CompletableFuture<Void> leftTask = CompletableFuture.runAsync(() -> concurrentMergeSort(array, temp, left, mid, executor, depth - 1), executor);
+
+        // Process the right half in the current thread to optimize resource usage
+        concurrentMergeSort(array, temp, mid + 1, right, executor, depth - 1);
+
+        // Wait for the concurrently executed left half to complete
+        leftTask.join();
+
+        merge(array, temp, left, mid, right);
+    }
+
+    /**
+     * Sorts the specified sub-array sequentially using standard Merge Sort.
+     *
+     * @param array the array to sort
+     * @param temp  a temporary array for merging
+     * @param left  the starting index of the sub-array
+     * @param right the ending index of the sub-array
+     */
+    private static void sequentialMergeSort(int[] array, int[] temp, int left, int right) {
+        if (left >= right) {
+            return;
+        }
+
+        int mid = left + (right - left) / 2;
+        sequentialMergeSort(array, temp, left, mid);
+        sequentialMergeSort(array, temp, mid + 1, right);
+        merge(array, temp, left, mid, right);
+    }
+
+    /**
+     * Merges two sorted sub-arrays into a single sorted sub-array.
+     *
+     * @param array the original array containing the sub-arrays
+     * @param temp  a temporary array used for merging
+     * @param left  the starting index of the first sub-array
+     * @param mid   the ending index of the first sub-array (and the partition point)
+     * @param right the ending index of the second sub-array
+     */
+    private static void merge(int[] array, int[] temp, int left, int mid, int right) {
+        System.arraycopy(array, left, temp, left, right - left + 1);
+
+        int i = left;
+        int j = mid + 1;
+        int k = left;
+
+        while (i <= mid && j <= right) {
+            if (temp[i] <= temp[j]) {
+                array[k++] = temp[i++];
+            } else {
+                array[k++] = temp[j++];
+            }
+        }
+
+        while (i <= mid) {
+            array[k++] = temp[i++];
+        }
+
+        // Remaining elements from the right half are already in their correct relative positions
+    }
+}
diff --git a/src/test/java/com/thealgorithms/sorts/ConcurrentMergeSortTest.java b/src/test/java/com/thealgorithms/sorts/ConcurrentMergeSortTest.java
new file mode 100644
index 000000000000..454d0bd26929
--- /dev/null
+++ b/src/test/java/com/thealgorithms/sorts/ConcurrentMergeSortTest.java
@@ -0,0 +1,93 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.Arrays;
+import java.util.Random;
+import org.junit.jupiter.api.Test;
+
+/**
+ * JUnit 5 test class for {@link ConcurrentMergeSort}.
+ */
+public class ConcurrentMergeSortTest {
+
+    @Test
+    public void testAlreadySortedArray() {
+        int[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        int[] expected = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+
+        ConcurrentMergeSort.sort(array);
+
+        assertArrayEquals(expected, array, "Already sorted array should remain unchanged.");
+    }
+
+    @Test
+    public void testReverseSortedArray() {
+        int[] array = {10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
+        int[] expected = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+
+        ConcurrentMergeSort.sort(array);
+
+        assertArrayEquals(expected, array, "Reverse sorted array should be sorted correctly.");
+    }
+
+    @Test
+    public void testIdenticalElementsArray() {
+        int[] array = {5, 5, 5, 5, 5, 5, 5};
+        int[] expected = {5, 5, 5, 5, 5, 5, 5};
+
+        ConcurrentMergeSort.sort(array);
+
+        assertArrayEquals(expected, array, "Array with identical elements should be sorted correctly (unchanged).");
+    }
+
+    @Test
+    public void testLargeRandomArray() {
+        int size = 100_000;
+        int[] array = new int[size];
+        int[] expected = new int[size];
+        // Using a fixed seed for deterministic testing
+        Random random = new Random(42);
+
+        for (int i = 0; i < size; i++) {
+            int value = random.nextInt();
+            array[i] = value;
+            expected[i] = value;
+        }
+
+        // Generate the expected result using Java's highly optimized built-in sort
+        Arrays.sort(expected);
+
+        // This will easily trigger the concurrency threshold (8192) in the implementation
+        ConcurrentMergeSort.sort(array);
+
+        assertArrayEquals(expected, array, "Large random array should be sorted correctly utilizing concurrency.");
+    }
+
+    @Test
+    public void testEmptyArray() {
+        int[] array = {};
+        int[] expected = {};
+
+        ConcurrentMergeSort.sort(array);
+
+        assertArrayEquals(expected, array, "Empty array should be handled without errors.");
+    }
+
+    @Test
+    public void testSingleElementArray() {
+        int[] array = {42};
+        int[] expected = {42};
+
+        ConcurrentMergeSort.sort(array);
+
+        assertArrayEquals(expected, array, "Single element array should be handled without errors.");
+    }
+
+    @Test
+    public void testNullArray() {
+        int[] array = null;
+        ConcurrentMergeSort.sort(array);
+        org.junit.jupiter.api.Assertions.assertNull(array, "Null array should be handled without errors.");
+    }
+}

From 7c934add6ef8ce1090d6add0403e2dc381b66b1a Mon Sep 17 00:00:00 2001
From: Chaiyong Ragkhitwetsagul <cragkhit@gmail.com>
Date: Sun, 2 Aug 2026 16:33:44 +0700
Subject: [PATCH 1321/1338] Reject null BitonicSort input explicitly (#7550)

Update BitonicSort.java

Added a descriptive null-input validation and a focused regression test.
---
 src/main/java/com/thealgorithms/sorts/BitonicSort.java   | 3 +++
 .../java/com/thealgorithms/sorts/BitonicSortTest.java    | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/src/main/java/com/thealgorithms/sorts/BitonicSort.java b/src/main/java/com/thealgorithms/sorts/BitonicSort.java
index 1c1a3ac45540..a714809ea5b2 100644
--- a/src/main/java/com/thealgorithms/sorts/BitonicSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BitonicSort.java
@@ -21,6 +21,9 @@ private enum Direction {
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array == null) {
+            throw new IllegalArgumentException("The input array cannot be null");
+        }
         if (array.length == 0) {
             return array;
         }
diff --git a/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java b/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java
index 60c4bbe9d342..2ee30c44e282 100644
--- a/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java
@@ -1,8 +1,17 @@
 package com.thealgorithms.sorts;
 
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
 public class BitonicSortTest extends SortingAlgorithmTest {
     @Override
     SortAlgorithm getSortAlgorithm() {
         return new BitonicSort();
     }
+
+    @Test
+    void shouldRejectNullArray() {
+        assertThrows(IllegalArgumentException.class, () -> getSortAlgorithm().sort((Integer[]) null));
+    }
 }

From 90f4231d9e072ec1dc855f22256a219f16e2edd8 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 4 Aug 2026 00:54:41 +0300
Subject: [PATCH 1322/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.8.0 to 13.9.0 (#7554)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.8.0 to 13.9.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.8.0...checkstyle-13.9.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.9.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 80fb3a6f8b2c..31ca9a59e025 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.8.0</version>
+                    <version>13.9.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From ec0f2cddccdeb484b8fa4728b2f93032a3ca610f Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 4 Aug 2026 01:00:34 +0300
Subject: [PATCH 1323/1338] chore(deps): bump actions/stale from 10.4.0 to
 11.0.0 in /.github/workflows (#7553)

chore(deps): bump actions/stale in /.github/workflows

Bumps [actions/stale](https://github.com/actions/stale) from 10.4.0 to 11.0.0.
- [Release notes](https://github.com/actions/stale/releases)
- [Changelog](https://github.com/actions/stale/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/stale/compare/v10.4.0...v11.0.0)

---
updated-dependencies:
- dependency-name: actions/stale
  dependency-version: 11.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 .github/workflows/stale.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index c94d2040aac4..b961d15c240e 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -11,7 +11,7 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/stale@v10.4.0
+      - uses: actions/stale@v11.0.0
         with:
           stale-issue-message: 'This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution!'
           close-issue-message: 'Please reopen this issue once you have made the required changes. If you need help, feel free to ask in our [Discord](https://the-algorithms.com/discord) server or ping one of the maintainers here. Thank you for your contribution!'

From 171bdc5cb06df69d9070d5ed1f95a3544a4276e9 Mon Sep 17 00:00:00 2001
From: Sepuri Sai Krishna <saik20533@gmail.com>
Date: Wed, 5 Aug 2026 12:47:13 +0530
Subject: [PATCH 1324/1338] Fix infinite loop in JumpSearch when key exceeds
 last element (#7555)

---
 .../thealgorithms/searches/JumpSearch.java    |  2 +-
 .../searches/JumpSearchTest.java              | 48 +++++++++++++++++++
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/JumpSearch.java b/src/main/java/com/thealgorithms/searches/JumpSearch.java
index 5074aa7845c8..4253f4182db1 100644
--- a/src/main/java/com/thealgorithms/searches/JumpSearch.java
+++ b/src/main/java/com/thealgorithms/searches/JumpSearch.java
@@ -73,7 +73,7 @@ public <T extends Comparable<T>> int find(T[] array, T key) {
         int limit = blockSize;
         // Jumping ahead to find the block where the key may be located
         while (limit < length && key.compareTo(array[limit]) > 0) {
-            limit = Math.min(limit + blockSize, length - 1);
+            limit += blockSize;
         }
 
         // Perform linear search within the identified block
diff --git a/src/test/java/com/thealgorithms/searches/JumpSearchTest.java b/src/test/java/com/thealgorithms/searches/JumpSearchTest.java
index 3fa319b66a41..a5ce93b8a3af 100644
--- a/src/test/java/com/thealgorithms/searches/JumpSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/JumpSearchTest.java
@@ -2,7 +2,9 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import java.util.concurrent.TimeUnit;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
 
 /**
  * Unit tests for the JumpSearch class.
@@ -91,4 +93,50 @@ void testJumpSearchLargeArrayNotFound() {
         Integer key = 999; // Key not present
         assertEquals(-1, jumpSearch.find(array, key), "The element should not be found in the array.");
     }
+
+    /**
+     * A key greater than every element used to make the jumping loop spin forever, because the
+     * cursor was clamped to the last index and therefore stopped advancing.
+     */
+    @Test
+    @Timeout(value = 5, unit = TimeUnit.SECONDS, threadMode = Timeout.ThreadMode.SEPARATE_THREAD)
+    void testJumpSearchKeyGreaterThanLastElement() {
+        JumpSearch jumpSearch = new JumpSearch();
+        Integer[] array = {1, 2, 3, 4};
+        assertEquals(-1, jumpSearch.find(array, 5), "A key above the maximum should not be found.");
+    }
+
+    /**
+     * The same regression across several lengths, since the jump size depends on the array length.
+     */
+    @Test
+    @Timeout(value = 5, unit = TimeUnit.SECONDS, threadMode = Timeout.ThreadMode.SEPARATE_THREAD)
+    void testJumpSearchKeyGreaterThanLastElementForEveryLength() {
+        JumpSearch jumpSearch = new JumpSearch();
+        for (int length = 1; length <= 50; length++) {
+            Integer[] array = new Integer[length];
+            for (int i = 0; i < length; i++) {
+                array[i] = i;
+            }
+            assertEquals(-1, jumpSearch.find(array, length), "A key above the maximum should not be found for length " + length + ".");
+        }
+    }
+
+    /**
+     * Every element must be found regardless of the array length, including the ones that sit
+     * exactly on a jump boundary.
+     */
+    @Test
+    void testJumpSearchFindsEveryElement() {
+        JumpSearch jumpSearch = new JumpSearch();
+        for (int length = 1; length <= 50; length++) {
+            Integer[] array = new Integer[length];
+            for (int i = 0; i < length; i++) {
+                array[i] = i * 2;
+            }
+            for (int i = 0; i < length; i++) {
+                assertEquals(i, jumpSearch.find(array, i * 2), "Element at index " + i + " should be found for length " + length + ".");
+            }
+        }
+    }
 }

From 55f551b17bd0c48b7cb1ba7ecfb7092803c7a150 Mon Sep 17 00:00:00 2001
From: Sepuri Sai Krishna <saik20533@gmail.com>
Date: Wed, 5 Aug 2026 13:07:32 +0530
Subject: [PATCH 1325/1338] Fix ExponentialSearch missing boundary elements and
 not returning -1 (#7556)

Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 .../searches/ExponentialSearch.java           |  5 ++-
 .../searches/ExponentialSearchTest.java       | 42 +++++++++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/ExponentialSearch.java b/src/main/java/com/thealgorithms/searches/ExponentialSearch.java
index 9187dcbc2f4b..e666b9148aaa 100644
--- a/src/main/java/com/thealgorithms/searches/ExponentialSearch.java
+++ b/src/main/java/com/thealgorithms/searches/ExponentialSearch.java
@@ -46,6 +46,9 @@ public <T extends Comparable<T>> int find(T[] array, T key) {
             range = range * 2;
         }
 
-        return Arrays.binarySearch(array, range / 2, Math.min(range, array.length), key);
+        // The candidate block is the inclusive index range [range / 2, range], so the
+        // exclusive upper bound handed to binarySearch has to be range + 1.
+        final int index = Arrays.binarySearch(array, range / 2, Math.min(range + 1, array.length), key);
+        return index >= 0 ? index : -1;
     }
 }
diff --git a/src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java b/src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java
index c84da531e8a4..c6b07ca2b4d5 100644
--- a/src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/ExponentialSearchTest.java
@@ -81,4 +81,46 @@ void testExponentialSearchLargeArray() {
         int expectedIndex = 9999;
         assertEquals(expectedIndex, exponentialSearch.find(array, key), "The index of the last element should be 9999.");
     }
+
+    /**
+     * An element sitting exactly on the doubling boundary used to be reported as missing, because
+     * the binary search was handed {@code range} as its exclusive upper bound instead of
+     * {@code range + 1}.
+     */
+    @Test
+    void testExponentialSearchElementOnRangeBoundary() {
+        ExponentialSearch exponentialSearch = new ExponentialSearch();
+        Integer[] array = {-25, -9, 8, 21};
+        assertEquals(2, exponentialSearch.find(array, 8), "The index of the found element should be 2.");
+    }
+
+    /**
+     * Every element must be found regardless of the array length.
+     */
+    @Test
+    void testExponentialSearchFindsEveryElement() {
+        ExponentialSearch exponentialSearch = new ExponentialSearch();
+        for (int length = 1; length <= 50; length++) {
+            Integer[] array = new Integer[length];
+            for (int i = 0; i < length; i++) {
+                array[i] = i * 2;
+            }
+            for (int i = 0; i < length; i++) {
+                assertEquals(i, exponentialSearch.find(array, i * 2), "Element at index " + i + " should be found for length " + length + ".");
+            }
+        }
+    }
+
+    /**
+     * A missing key has to yield -1 rather than the negative insertion point that
+     * {@link java.util.Arrays#binarySearch} returns.
+     */
+    @Test
+    void testExponentialSearchNotFoundReturnsMinusOne() {
+        ExponentialSearch exponentialSearch = new ExponentialSearch();
+        Integer[] array = {1, 3, 5, 7, 9, 11};
+        assertEquals(-1, exponentialSearch.find(array, 4), "A key inside the range but absent should give -1.");
+        assertEquals(-1, exponentialSearch.find(array, 0), "A key below the minimum should give -1.");
+        assertEquals(-1, exponentialSearch.find(array, 12), "A key above the maximum should give -1.");
+    }
 }

From 0b0f9218ddeec71548363ac4d5eddf354988f127 Mon Sep 17 00:00:00 2001
From: Sepuri Sai Krishna <saik20533@gmail.com>
Date: Thu, 6 Aug 2026 01:10:27 +0530
Subject: [PATCH 1326/1338] Fix out-of-bounds access and identity comparison in
 FibonacciSearch (#7557)

---
 .../searches/FibonacciSearch.java             |  2 +-
 .../searches/FibonacciSearchTest.java         | 49 +++++++++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/FibonacciSearch.java b/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
index 78dac0f0a712..fa91cd14a1af 100644
--- a/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
+++ b/src/main/java/com/thealgorithms/searches/FibonacciSearch.java
@@ -69,7 +69,7 @@ public <T extends Comparable<T>> int find(T[] array, T key) {
             }
         }
 
-        if (fibMinus1 == 1 && array[offset + 1] == key) {
+        if (fibMinus1 == 1 && offset + 1 < n && array[offset + 1].compareTo(key) == 0) {
             return offset + 1;
         }
 
diff --git a/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java b/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java
index 801c33b1d09a..04a270864223 100644
--- a/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/FibonacciSearchTest.java
@@ -121,4 +121,53 @@ void testFibonacciSearchLargeArray() {
         int expectedIndex = 9999;
         assertEquals(expectedIndex, fibonacciSearch.find(array, key), "The index of the last element should be 9999.");
     }
+
+    /**
+     * A key greater than every element used to throw {@link ArrayIndexOutOfBoundsException},
+     * because the final probe read {@code array[offset + 1]} without checking the bound.
+     */
+    @Test
+    void testFibonacciSearchKeyGreaterThanLastElement() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        for (int length = 1; length <= 50; length++) {
+            Integer[] array = new Integer[length];
+            for (int i = 0; i < length; i++) {
+                array[i] = i;
+            }
+            assertEquals(-1, fibonacciSearch.find(array, length), "A key above the maximum should not be found for length " + length + ".");
+        }
+    }
+
+    /**
+     * The final probe used reference equality, so a key that is equal but not identical to the
+     * stored element was reported as missing. Values above 127 are outside the {@link Integer}
+     * cache and therefore are not the same object as the boxed array element.
+     */
+    @Test
+    void testFibonacciSearchFindsEqualButNotIdenticalKey() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        Integer[] array = {10, 20, 300};
+        assertEquals(2, fibonacciSearch.find(array, Integer.valueOf(300)), "The index of the found element should be 2.");
+
+        String[] words = {"a", "b", "c"};
+        String equalButDistinct = new StringBuilder("c").toString();
+        assertEquals(2, fibonacciSearch.find(words, equalButDistinct), "The index of the found element should be 2.");
+    }
+
+    /**
+     * Every element must be found regardless of the array length.
+     */
+    @Test
+    void testFibonacciSearchFindsEveryElement() {
+        FibonacciSearch fibonacciSearch = new FibonacciSearch();
+        for (int length = 1; length <= 50; length++) {
+            Integer[] array = new Integer[length];
+            for (int i = 0; i < length; i++) {
+                array[i] = 1000 + i * 2;
+            }
+            for (int i = 0; i < length; i++) {
+                assertEquals(i, fibonacciSearch.find(array, Integer.valueOf(1000 + i * 2)), "Element at index " + i + " should be found for length " + length + ".");
+            }
+        }
+    }
 }

From a521d93ea6adfb1c4e2da7b5b6173a998617f42b Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sun, 9 Aug 2026 19:50:33 +0200
Subject: [PATCH 1327/1338] chore(deps): bump actions/setup-java from 5.6.0 to
 5.7.0 in /.github/workflows (#7566)

chore(deps): bump actions/setup-java in /.github/workflows

Bumps [actions/setup-java](https://github.com/actions/setup-java) from 5.6.0 to 5.7.0.
- [Release notes](https://github.com/actions/setup-java/releases)
- [Commits](https://github.com/actions/setup-java/compare/v5.6.0...v5.7.0)

---
updated-dependencies:
- dependency-name: actions/setup-java
  dependency-version: 5.7.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/build.yml  | 2 +-
 .github/workflows/codeql.yml | 2 +-
 .github/workflows/infer.yml  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 03ca693a5af0..a1395d87ec8d 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@v7
       - name: Set up JDK
-        uses: actions/setup-java@v5.6.0
+        uses: actions/setup-java@v5.7.0
         with:
           java-version: 21
           distribution: 'temurin'
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index d8e87d5363d5..6c51bf268b0c 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -24,7 +24,7 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Set up JDK
-        uses: actions/setup-java@v5.6.0
+        uses: actions/setup-java@v5.7.0
         with:
           java-version: 21
           distribution: 'temurin'
diff --git a/.github/workflows/infer.yml b/.github/workflows/infer.yml
index cc15da8d0b00..3bfc509ebf47 100644
--- a/.github/workflows/infer.yml
+++ b/.github/workflows/infer.yml
@@ -18,7 +18,7 @@ jobs:
       - uses: actions/checkout@v7
 
       - name: Set up JDK
-        uses: actions/setup-java@v5.6.0
+        uses: actions/setup-java@v5.7.0
         with:
           java-version: 21
           distribution: 'temurin'

From 77be010940237389a33b14c8ed0debf6c2b7bceb Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sun, 9 Aug 2026 17:53:45 +0000
Subject: [PATCH 1328/1338] chore(deps): bump github/codeql-action from 4.37.3
 to 4.37.4 in /.github/workflows (#7565)

chore(deps): bump github/codeql-action in /.github/workflows

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4.37.3 to 4.37.4.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v4.37.3...v4.37.4)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: 4.37.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 6c51bf268b0c..18ac8b1215de 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.3
+        uses: github/codeql-action/init@v4.37.4
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.3
+        uses: github/codeql-action/analyze@v4.37.4
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.3
+        uses: github/codeql-action/init@v4.37.4
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.3
+        uses: github/codeql-action/analyze@v4.37.4
         with:
           category: "/language:actions"
 ...

From 8e456f64a734011cc7c3d92edc66e6e082e1aa9f Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 11 Aug 2026 08:21:46 +0300
Subject: [PATCH 1329/1338] chore(deps): bump github/codeql-action from 4.37.4
 to 4.37.5 in /.github/workflows (#7569)

chore(deps): bump github/codeql-action in /.github/workflows

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4.37.4 to 4.37.5.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v4.37.4...v4.37.5)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: 4.37.5
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 18ac8b1215de..995993df653f 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.4
+        uses: github/codeql-action/init@v4.37.5
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.4
+        uses: github/codeql-action/analyze@v4.37.5
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.4
+        uses: github/codeql-action/init@v4.37.5
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.4
+        uses: github/codeql-action/analyze@v4.37.5
         with:
           category: "/language:actions"
 ...

From bc41b6465e78652b89173a77856cdc44e5d2c5a0 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Tue, 11 Aug 2026 08:30:04 +0300
Subject: [PATCH 1330/1338] chore(deps): bump
 org.apache.commons:commons-collections4 from 4.5.0 to 4.6.0 (#7568)

chore(deps): bump org.apache.commons:commons-collections4

Bumps org.apache.commons:commons-collections4 from 4.5.0 to 4.6.0.

---
updated-dependencies:
- dependency-name: org.apache.commons:commons-collections4
  dependency-version: 4.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 31ca9a59e025..dfc6e1056cc4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -53,7 +53,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-collections4</artifactId>
-            <version>4.5.0</version>
+            <version>4.6.0</version>
         </dependency>
     </dependencies>
 

From fdfb9a395b310167a66bd29e311e36e0e3e9b964 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Wed, 12 Aug 2026 09:09:38 +0300
Subject: [PATCH 1331/1338] chore(deps): bump github/codeql-action from 4.37.5
 to 4.37.6 in /.github/workflows (#7570)

chore(deps): bump github/codeql-action in /.github/workflows

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4.37.5 to 4.37.6.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v4.37.5...v4.37.6)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: 4.37.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 995993df653f..4861e5df2b29 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.5
+        uses: github/codeql-action/init@v4.37.6
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.5
+        uses: github/codeql-action/analyze@v4.37.6
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.5
+        uses: github/codeql-action/init@v4.37.6
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.5
+        uses: github/codeql-action/analyze@v4.37.6
         with:
           category: "/language:actions"
 ...

From 346f591578705ff7493972c82ec327f7e217d238 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Sat, 15 Aug 2026 00:52:49 +0300
Subject: [PATCH 1332/1338] chore(deps): bump org.junit:junit-bom from 6.1.2 to
 6.1.3 (#7571)

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit-framework) from 6.1.2 to 6.1.3.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](https://github.com/junit-team/junit-framework/compare/r6.1.2...r6.1.3)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 6.1.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index dfc6e1056cc4..68b72189fdb3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,7 +20,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>6.1.2</version>
+                <version>6.1.3</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

From a0f6b0df7afc4555958a5f55a4e51501eb88bb86 Mon Sep 17 00:00:00 2001
From: Sepuri Sai Krishna <saik20533@gmail.com>
Date: Sat, 15 Aug 2026 22:26:25 +0530
Subject: [PATCH 1333/1338] fix: RailFenceCipher silently drops newline
 characters (#7572)

Fix character loss in RailFenceCipher for inputs containing newlines
---
 .../ciphers/RailFenceCipher.java              | 56 ++++++++-------
 .../ciphers/RailFenceCipherTest.java          | 70 +++++++++++++++++++
 2 files changed, 99 insertions(+), 27 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/ciphers/RailFenceCipherTest.java

diff --git a/src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java b/src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java
index f81252980468..324dc88e4f19 100644
--- a/src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java
+++ b/src/main/java/com/thealgorithms/ciphers/RailFenceCipher.java
@@ -1,7 +1,5 @@
 package com.thealgorithms.ciphers;
 
-import java.util.Arrays;
-
 /**
  * The rail fence cipher (also called a zigzag cipher) is a classical type of transposition cipher.
  * It derives its name from the manner in which encryption is performed, in analogy to a fence built with horizontal rails.
@@ -14,28 +12,27 @@ public class RailFenceCipher {
     // Encrypts the input string using the rail fence cipher method with the given number of rails.
     public String encrypt(String str, int rails) {
 
+        checkInput(str, rails);
+
         // Base case of single rail or rails are more than the number of characters in the string
         if (rails == 1 || rails >= str.length()) {
             return str;
         }
 
-        // Boolean flag to determine if the movement is downward or upward in the rail matrix.
+        // Boolean flag to determine if the movement is downward or upward in the rail pattern.
         boolean down = true;
-        // Create a 2D array to represent the rails (rows) and the length of the string (columns).
-        char[][] strRail = new char[rails][str.length()];
-
-        // Initialize all positions in the rail matrix with a placeholder character ('\n').
+        // Collect the characters of every rail separately. Using one buffer per rail (instead of a
+        // rails x length matrix with a placeholder character) keeps every character of the input,
+        // including characters that would otherwise be indistinguishable from the placeholder.
+        StringBuilder[] railBuffers = new StringBuilder[rails];
         for (int i = 0; i < rails; i++) {
-            Arrays.fill(strRail[i], '\n');
+            railBuffers[i] = new StringBuilder();
         }
 
-        int row = 0; // Start at the first row
-        int col = 0; // Start at the first column
+        int row = 0; // Start at the first rail
 
-        int i = 0;
-
-        // Fill the rail matrix with characters from the string based on the rail pattern.
-        while (col < str.length()) {
+        // Distribute the characters of the string over the rails following the zigzag pattern.
+        for (int i = 0; i < str.length(); i++) {
             // Change direction to down when at the first row.
             if (row == 0) {
                 down = true;
@@ -45,33 +42,28 @@ else if (row == rails - 1) {
                 down = false;
             }
 
-            // Place the character in the current position of the rail matrix.
-            strRail[row][col] = str.charAt(i);
-            col++; // Move to the next column.
+            // Append the character to the rail it belongs to.
+            railBuffers[row].append(str.charAt(i));
             // Move to the next row based on the direction.
             if (down) {
                 row++;
             } else {
                 row--;
             }
-
-            i++;
         }
 
-        // Construct the encrypted string by reading characters row by row.
-        StringBuilder encryptedString = new StringBuilder();
-        for (char[] chRow : strRail) {
-            for (char ch : chRow) {
-                if (ch != '\n') {
-                    encryptedString.append(ch);
-                }
-            }
+        // Construct the encrypted string by reading the rails top to bottom.
+        StringBuilder encryptedString = new StringBuilder(str.length());
+        for (StringBuilder railBuffer : railBuffers) {
+            encryptedString.append(railBuffer);
         }
         return encryptedString.toString();
     }
     // Decrypts the input string using the rail fence cipher method with the given number of rails.
     public String decrypt(String str, int rails) {
 
+        checkInput(str, rails);
+
         // Base case of single rail or rails are more than the number of characters in the string
         if (rails == 1 || rails >= str.length()) {
             return str;
@@ -144,4 +136,14 @@ else if (row == rails - 1) {
 
         return decryptedString.toString();
     }
+
+    // Rejects inputs the zigzag pattern is not defined for.
+    private static void checkInput(String str, int rails) {
+        if (str == null) {
+            throw new IllegalArgumentException("Input string must not be null");
+        }
+        if (rails <= 0) {
+            throw new IllegalArgumentException("Number of rails must be positive, but was " + rails);
+        }
+    }
 }
diff --git a/src/test/java/com/thealgorithms/ciphers/RailFenceCipherTest.java b/src/test/java/com/thealgorithms/ciphers/RailFenceCipherTest.java
new file mode 100644
index 000000000000..041f8c0dd4c1
--- /dev/null
+++ b/src/test/java/com/thealgorithms/ciphers/RailFenceCipherTest.java
@@ -0,0 +1,70 @@
+package com.thealgorithms.ciphers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class RailFenceCipherTest {
+
+    private final RailFenceCipher railFenceCipher = new RailFenceCipher();
+
+    @Test
+    void testEncrypt() {
+        assertEquals("WECRLTEERDSOEEFEAOCAIVDEN", railFenceCipher.encrypt("WEAREDISCOVEREDFLEEATONCE", 3));
+    }
+
+    @Test
+    void testDecrypt() {
+        assertEquals("WEAREDISCOVEREDFLEEATONCE", railFenceCipher.decrypt("WECRLTEERDSOEEFEAOCAIVDEN", 3));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"HELLOWORLD, 2", "HELLOWORLD, 3", "HELLOWORLD, 4", "ATTACKATDAWN, 5", "abcdefghij, 6"})
+    void testRoundTrip(String message, int rails) {
+        assertEquals(message, railFenceCipher.decrypt(railFenceCipher.encrypt(message, rails), rails));
+    }
+
+    /**
+     * Every character of the input must survive encryption, including the ones that used to collide
+     * with the placeholder that marked unused cells of the rail matrix.
+     */
+    @ParameterizedTest
+    @ValueSource(strings = {"ab\ncdef", "line1\nline2\nline3", "\n\n\n\n\n", "a\nb", "tabs\tand\nnewlines\r\n"})
+    void testControlCharactersArePreserved(String message) {
+        for (int rails = 2; rails <= 5; rails++) {
+            String encrypted = railFenceCipher.encrypt(message, rails);
+            assertEquals(message.length(), encrypted.length(), "characters were dropped with " + rails + " rails");
+            assertEquals(message, railFenceCipher.decrypt(encrypted, rails), "round trip failed with " + rails + " rails");
+        }
+    }
+
+    @Test
+    void testEncryptWithNewlineMatchesReferencePattern() {
+        // Rails of "ab\ncdef" with 3 rails: {a, d} / {b, c, e} / {\n, f}
+        assertEquals("adbce\nf", railFenceCipher.encrypt("ab\ncdef", 3));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"HELLO, 1", "HELLO, 5", "HELLO, 9", "'', 1", "'', 4"})
+    void testDegenerateRailCountsReturnInput(String message, int rails) {
+        assertEquals(message, railFenceCipher.encrypt(message, rails));
+        assertEquals(message, railFenceCipher.decrypt(message, rails));
+    }
+
+    @ParameterizedTest
+    @ValueSource(ints = {0, -1, -7})
+    void testNonPositiveRailCountThrows(int rails) {
+        assertThrows(IllegalArgumentException.class, () -> railFenceCipher.encrypt("HELLO", rails));
+        assertThrows(IllegalArgumentException.class, () -> railFenceCipher.decrypt("HELLO", rails));
+    }
+
+    @Test
+    void testNullInputThrows() {
+        assertThrows(IllegalArgumentException.class, () -> railFenceCipher.encrypt(null, 3));
+        assertThrows(IllegalArgumentException.class, () -> railFenceCipher.decrypt(null, 3));
+    }
+}

From a050916b9f833630b05b15db07685bee92635d5f Mon Sep 17 00:00:00 2001
From: Sepuri Sai Krishna <saik20533@gmail.com>
Date: Mon, 17 Aug 2026 01:39:19 +0530
Subject: [PATCH 1334/1338] fix: off-by-one bounds guards in SegmentTree
 (#7573)

Fix off-by-one bounds guards in SegmentTree update and getSum
---
 .../datastructures/trees/SegmentTree.java     | 13 ++-
 .../datastructures/trees/SegmentTreeTest.java | 96 +++++++++++++++++++
 2 files changed, 106 insertions(+), 3 deletions(-)
 create mode 100644 src/test/java/com/thealgorithms/datastructures/trees/SegmentTreeTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
index 57b3edc163ca..af6acb0cbb2b 100644
--- a/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
+++ b/src/main/java/com/thealgorithms/datastructures/trees/SegmentTree.java
@@ -8,13 +8,18 @@ public class SegmentTree {
 
     /* Constructor which takes the size of the array and the array as a parameter*/
     public SegmentTree(int n, int[] arr) {
+        if (arr == null) {
+            throw new IllegalArgumentException("Input array must not be null");
+        }
+        if (n <= 0 || n > arr.length) {
+            throw new IllegalArgumentException("Size must be in the range [1, " + arr.length + "], but was " + n);
+        }
         this.n = n;
         int x = (int) (Math.ceil(Math.log(n) / Math.log(2)));
         int segSize = 2 * (int) Math.pow(2, x) - 1;
 
         this.segTree = new int[segSize];
         this.arr = arr;
-        this.n = n;
         constructTree(arr, 0, n - 1, 0);
     }
 
@@ -47,7 +52,8 @@ private void updateTree(int start, int end, int index, int diff, int segIndex) {
 
     /* A function to update the value at a particular index*/
     public void update(int index, int value) {
-        if (index < 0 || index > n) {
+        // Valid positions are 0..n-1; index == n is out of bounds and must not reach arr[index].
+        if (index < 0 || index >= n) {
             return;
         }
 
@@ -73,7 +79,8 @@ private int getSumTree(int start, int end, int qStart, int qEnd, int segIndex) {
 
     /* A function to query the sum of the subarray [start...end]*/
     public int getSum(int start, int end) {
-        if (start < 0 || end > n || start > end) {
+        // The last queryable position is n-1, so end == n is an out of range query.
+        if (start < 0 || end >= n || start > end) {
             return 0;
         }
         return getSumTree(0, n - 1, start, end, 0);
diff --git a/src/test/java/com/thealgorithms/datastructures/trees/SegmentTreeTest.java b/src/test/java/com/thealgorithms/datastructures/trees/SegmentTreeTest.java
new file mode 100644
index 000000000000..196c32575709
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/trees/SegmentTreeTest.java
@@ -0,0 +1,96 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class SegmentTreeTest {
+
+    private static SegmentTree treeOf(int... values) {
+        return new SegmentTree(values.length, values);
+    }
+
+    @ParameterizedTest
+    @CsvSource({"0, 4, 15", "0, 0, 1", "4, 4, 5", "1, 3, 9", "2, 4, 12"})
+    void testRangeSums(int start, int end, int expected) {
+        assertEquals(expected, treeOf(1, 2, 3, 4, 5).getSum(start, end));
+    }
+
+    @Test
+    void testSingleElementTree() {
+        SegmentTree tree = treeOf(42);
+        assertEquals(42, tree.getSum(0, 0));
+        tree.update(0, 7);
+        assertEquals(7, tree.getSum(0, 0));
+    }
+
+    @Test
+    void testUpdateIsReflectedInSubsequentQueries() {
+        SegmentTree tree = treeOf(1, 2, 3, 4, 5);
+        tree.update(2, 10);
+        assertEquals(22, tree.getSum(0, 4));
+        assertEquals(16, tree.getSum(1, 3));
+        tree.update(0, -1);
+        assertEquals(20, tree.getSum(0, 4));
+    }
+
+    @Test
+    void testNegativeValues() {
+        SegmentTree tree = treeOf(-5, 3, -2, 8);
+        assertEquals(4, tree.getSum(0, 3));
+        assertEquals(-4, tree.getSum(0, 2));
+    }
+
+    /**
+     * index == n is past the last element, so it must be rejected by the guard instead of reaching
+     * the backing array and throwing {@link ArrayIndexOutOfBoundsException}.
+     */
+    @ParameterizedTest
+    @ValueSource(ints = {5, 6, 100, -1})
+    void testUpdateOutOfRangeIndexIsIgnored(int index) {
+        SegmentTree tree = treeOf(1, 2, 3, 4, 5);
+        assertDoesNotThrow(() -> tree.update(index, 99));
+        assertEquals(15, tree.getSum(0, 4), "out of range update must not modify the tree");
+    }
+
+    @ParameterizedTest
+    @CsvSource({"0, 5", "0, 6", "3, 2", "-1, 3", "5, 5"})
+    void testOutOfRangeQueriesReturnZero(int start, int end) {
+        assertEquals(0, treeOf(1, 2, 3, 4, 5).getSum(start, end));
+    }
+
+    @Test
+    void testConstructorRejectsInvalidSize() {
+        assertThrows(IllegalArgumentException.class, () -> new SegmentTree(0, new int[] {1, 2, 3}));
+        assertThrows(IllegalArgumentException.class, () -> new SegmentTree(-1, new int[] {1, 2, 3}));
+        assertThrows(IllegalArgumentException.class, () -> new SegmentTree(4, new int[] {1, 2, 3}));
+    }
+
+    @Test
+    void testConstructorRejectsNullArray() {
+        assertThrows(IllegalArgumentException.class, () -> new SegmentTree(3, null));
+    }
+
+    @ParameterizedTest
+    @ValueSource(ints = {1, 2, 3, 4, 5, 6, 7, 8, 9, 16, 17})
+    void testMatchesBruteForceForVariousSizes(int size) {
+        int[] values = new int[size];
+        for (int i = 0; i < size; i++) {
+            values[i] = i * 3 - 4;
+        }
+        SegmentTree tree = new SegmentTree(size, values.clone());
+
+        for (int start = 0; start < size; start++) {
+            int expected = 0;
+            for (int end = start; end < size; end++) {
+                expected += values[end];
+                assertEquals(expected, tree.getSum(start, end), "sum of [" + start + ", " + end + "] with size " + size);
+            }
+        }
+    }
+}

From 56e2699defe911cf72cd421a1dffc7eb5adae816 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 17 Aug 2026 20:39:45 +0000
Subject: [PATCH 1335/1338] chore(deps): bump com.puppycrawl.tools:checkstyle
 from 13.9.0 to 13.10.0 (#7576)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 13.9.0 to 13.10.0.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](https://github.com/checkstyle/checkstyle/compare/checkstyle-13.9.0...checkstyle-13.10.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-version: 13.10.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index 68b72189fdb3..df36cfb6cdc7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,7 +112,7 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>13.9.0</version>
+                    <version>13.10.0</version>
                     </dependency>
                 </dependencies>
             </plugin>

From 3ddd05229e736cb5c0c42dae25bb45b9df4ad194 Mon Sep 17 00:00:00 2001
From: Sepuri Sai Krishna <saik20533@gmail.com>
Date: Wed, 19 Aug 2026 14:16:57 +0530
Subject: [PATCH 1336/1338] fix: integer overflow in MobiusFunction (#7574)

Fix integer overflow in MobiusFunction squared-factor check
---
 .../maths/Prime/MobiusFunction.java           | 27 ++++++++++---------
 .../maths/prime/MobiusFunctionTest.java       | 13 +++++++++
 2 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/src/main/java/com/thealgorithms/maths/Prime/MobiusFunction.java b/src/main/java/com/thealgorithms/maths/Prime/MobiusFunction.java
index 3d4e4eff0f03..ec1785a916c7 100644
--- a/src/main/java/com/thealgorithms/maths/Prime/MobiusFunction.java
+++ b/src/main/java/com/thealgorithms/maths/Prime/MobiusFunction.java
@@ -31,27 +31,28 @@ public static int mobius(int number) {
             throw new IllegalArgumentException("Number must be greater than zero.");
         }
 
-        if (number == 1) {
-            // return 1 if number passed is less or is 1
-            return 1;
-        }
-
         int primeFactorCount = 0;
+        int remaining = number;
 
-        for (int i = 1; i <= number; i++) {
-            // find prime factors of number
-            if (number % i == 0 && PrimeCheck.isPrime(i)) {
-                // check if number is divisible by square of prime factor
-                if (number % (i * i) == 0) {
-                    // if number is divisible by square of prime factor
+        /* Divide out every prime factor in turn. Trial division only has to run up to the square
+        root of the remaining value, and the multiplication is widened to long so that the bound
+        does not overflow for numbers close to Integer.MAX_VALUE. */
+        for (int factor = 2; (long) factor * factor <= remaining; factor++) {
+            if (remaining % factor == 0) {
+                remaining /= factor;
+                if (remaining % factor == 0) {
+                    // number is divisible by the square of this prime factor
                     return 0;
                 }
-                /*increment primeFactorCount by 1
-                                if number is not divisible by square of found prime factor*/
                 primeFactorCount++;
             }
         }
 
+        /* Whatever is left is either 1 or a single prime factor larger than the square root. */
+        if (remaining > 1) {
+            primeFactorCount++;
+        }
+
         return (primeFactorCount % 2 == 0) ? 1 : -1;
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/prime/MobiusFunctionTest.java b/src/test/java/com/thealgorithms/maths/prime/MobiusFunctionTest.java
index 734d02477ba2..98ac29e81a5b 100644
--- a/src/test/java/com/thealgorithms/maths/prime/MobiusFunctionTest.java
+++ b/src/test/java/com/thealgorithms/maths/prime/MobiusFunctionTest.java
@@ -5,6 +5,8 @@
 
 import com.thealgorithms.maths.Prime.MobiusFunction;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 class MobiusFunctionTest {
 
@@ -152,4 +154,15 @@ void testMobiusFunction() {
             assertEquals(expectedValue, actualValue);
         }
     }
+
+    /**
+     * Large inputs whose smallest square divisor test used to overflow, most notably
+     * {@code Integer.MAX_VALUE}, whose square wraps around to 1 and made every number look like it
+     * had a squared prime factor.
+     */
+    @ParameterizedTest
+    @CsvSource({"2147483647, -1", "2147483646, 0", "2147483645, -1", "2147483644, 0", "2147483629, -1", "2147395600, 0", "1073741824, 0", "1073741789, -1", "999999937, -1", "999999999, 0", "2146689000, 0"})
+    void testMobiusForLargeNumbers(int number, int expected) {
+        assertEquals(expected, MobiusFunction.mobius(number));
+    }
 }

From 65b977e0fe7244314326a62f17e2a8c0f596ba43 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 21 Aug 2026 08:00:29 +0300
Subject: [PATCH 1337/1338] chore(deps): bump github/codeql-action from 4.37.6
 to 4.37.7 in /.github/workflows (#7578)

chore(deps): bump github/codeql-action in /.github/workflows

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4.37.6 to 4.37.7.
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/v4.37.6...v4.37.7)

---
updated-dependencies:
- dependency-name: github/codeql-action
  dependency-version: 4.37.7
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 .github/workflows/codeql.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 4861e5df2b29..db2c7f5a1b46 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.6
+        uses: github/codeql-action/init@v4.37.7
         with:
           languages: 'java-kotlin'
 
@@ -38,7 +38,7 @@ jobs:
         run: mvn --batch-mode --update-snapshots verify
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.6
+        uses: github/codeql-action/analyze@v4.37.7
         with:
           category: "/language:java-kotlin"
 
@@ -55,12 +55,12 @@ jobs:
         uses: actions/checkout@v7
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.6
+        uses: github/codeql-action/init@v4.37.7
         with:
           languages: 'actions'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.6
+        uses: github/codeql-action/analyze@v4.37.7
         with:
           category: "/language:actions"
 ...

From 9d05db2d14702454a418ff31158905e502df83e0 Mon Sep 17 00:00:00 2001
From: iamcodinghere22 <amoghpatwari.25@gmail.com>
Date: Fri, 21 Aug 2026 14:23:26 +0530
Subject: [PATCH 1338/1338] feat(datastructures): add SelfOrganizingLinkedList
 implementation and tests (#7575)

* Add SquareFreeInteger to maths

* fix clang-format issues

* add newline

* Add new test file  in test

* modified

* delete

* Add DisariumNumbers  with test

* feat(datastructures): add SelfOrganizingLinkedList implementation and tests

* fix checkstyle formatting errors in SelfOrganizingLinkedList including test file.

* Add new Line as per the format

* fix(datastructures): prevent null dereference in SelfOrganizingLinkedList

* format correction

* format

* build format

* "

* format finally

* maybe

* done

* make corrections and add tests

* format

* build correction

* done

* pmd done

---------

Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>
---
 .../lists/SelfOrganizingLinkedList.java       | 105 ++++++++++++++++
 .../lists/SelfOrganizingLinkedListTest.java   | 119 ++++++++++++++++++
 2 files changed, 224 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/datastructures/lists/SelfOrganizingLinkedList.java
 create mode 100644 src/test/java/com/thealgorithms/datastructures/lists/SelfOrganizingLinkedListTest.java

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SelfOrganizingLinkedList.java b/src/main/java/com/thealgorithms/datastructures/lists/SelfOrganizingLinkedList.java
new file mode 100644
index 000000000000..200c636ce1ab
--- /dev/null
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SelfOrganizingLinkedList.java
@@ -0,0 +1,105 @@
+package com.thealgorithms.datastructures.lists;
+
+import java.util.Objects;
+
+/**
+ * A Self-Organizing Linked List implementation using the Move-To-Front (MTF) strategy.
+ * When an element is searched, it is automatically moved to the head of the list
+ * to optimize subsequent lookups.
+ *
+ * @param <E> the type of elements held in this list
+ */
+public class SelfOrganizingLinkedList<E> {
+
+    /**
+     * Node structure for the self-organizing linked list.
+     *
+     * @param <E> the type of element held in this node
+     */
+    private static class Node<E> {
+        E value;
+        Node<E> next;
+
+        Node(E value) {
+            this.value = value;
+            this.next = null;
+        }
+    }
+
+    private Node<E> head;
+    private int size;
+
+    public SelfOrganizingLinkedList() {
+        this.size = 0;
+        this.head = null;
+    }
+
+    /**
+     * Inserts a new value at the end of the list.
+     *
+     * @param value the element to add
+     */
+    public void insert(E value) {
+        Node<E> newNode = new Node<>(value);
+        if (head == null) {
+            head = newNode;
+        } else {
+            Node<E> temp = head;
+            while (temp.next != null) {
+                temp = temp.next;
+            }
+            temp.next = newNode;
+        }
+        size++;
+    }
+
+    /**
+     * Searches for a value in the list.
+     * If found, moves the node to the front (head) of the list.
+     *
+     * @param key the value to search for
+     * @return true if the element is present, false otherwise
+     */
+    public boolean search(E key) {
+        if (head == null) {
+            return false;
+        }
+        // If the key is already at the head, no pointers need to be rewired
+        if (Objects.equals(head.value, key)) {
+            return true;
+        }
+
+        Node<E> prev = head;
+        Node<E> curr = head.next;
+
+        while (curr != null && !Objects.equals(curr.value, key)) {
+            prev = curr;
+            curr = curr.next;
+        }
+
+        if (curr == null) {
+            return false;
+        }
+
+        // Unlink curr from its current position and move it to head
+        prev.next = curr.next;
+        curr.next = head;
+        head = curr;
+        return true;
+    }
+
+    /** Gets the current head value of the list. */
+    public E getHeadValue() {
+        return head != null ? head.value : null;
+    }
+
+    /** Returns the size of the list. */
+    public int getSize() {
+        return size;
+    }
+
+    /** Returns true if the list contains no elements. */
+    public boolean isEmpty() {
+        return size == 0;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SelfOrganizingLinkedListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SelfOrganizingLinkedListTest.java
new file mode 100644
index 000000000000..1d397cf09301
--- /dev/null
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SelfOrganizingLinkedListTest.java
@@ -0,0 +1,119 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class SelfOrganizingLinkedListTest {
+
+    private SelfOrganizingLinkedList<Integer> list;
+
+    @BeforeEach
+    void setUp() {
+        list = new SelfOrganizingLinkedList<>();
+    }
+
+    @Test
+    void testEmptyListAndGetters() {
+        assertTrue(list.isEmpty());
+        assertEquals(0, list.getSize());
+        assertNull(list.getHeadValue());
+        assertFalse(list.search(10));
+    }
+
+    @Test
+    void testInsertAndSizeState() {
+        assertTrue(list.isEmpty());
+        list.insert(10);
+        assertFalse(list.isEmpty());
+        assertEquals(1, list.getSize());
+
+        list.insert(20);
+        assertEquals(2, list.getSize());
+    }
+
+    @Test
+    void testMoveMiddleElementToFrontPreservesFullListStructure() {
+        list.insert(10);
+        list.insert(20);
+        list.insert(30);
+        list.insert(40);
+
+        // Initial order: [10, 20, 30, 40]
+        assertTrue(list.search(30));
+
+        // Expected order: [30, 10, 20, 40]
+        assertEquals(4, list.getSize());
+        assertEquals(30, list.getHeadValue());
+
+        // Sequential head tracking to verify middle and tail pointers didn't break
+        assertTrue(list.search(10)); // [10, 30, 20, 40]
+        assertEquals(10, list.getHeadValue());
+
+        assertTrue(list.search(20)); // [20, 10, 30, 40]
+        assertEquals(20, list.getHeadValue());
+
+        assertTrue(list.search(40)); // [40, 20, 10, 30]
+        assertEquals(40, list.getHeadValue());
+        assertEquals(4, list.getSize());
+    }
+
+    @Test
+    void testMoveLastElementToFrontPreservesFullListStructure() {
+        list.insert(10);
+        list.insert(20);
+        list.insert(30);
+
+        // Search tail element '30'
+        assertTrue(list.search(30)); // Order becomes [30, 10, 20]
+
+        assertEquals(30, list.getHeadValue());
+        assertEquals(3, list.getSize());
+
+        // Verify remaining chain order [10, 20]
+        assertTrue(list.search(20)); // [20, 30, 10]
+        assertEquals(20, list.getHeadValue());
+
+        assertTrue(list.search(10)); // [10, 20, 30]
+        assertEquals(10, list.getHeadValue());
+        assertEquals(3, list.getSize());
+    }
+
+    @Test
+    void testSearchNonExistentElementPreservesStructureAndSize() {
+        list.insert(10);
+        list.insert(20);
+        list.insert(30);
+
+        assertFalse(list.search(99));
+        assertEquals(3, list.getSize());
+        assertEquals(10, list.getHeadValue());
+    }
+
+    @Test
+    void testDuplicateValuesMovesFirstMatchedToFront() {
+        list.insert(10);
+        list.insert(20);
+        list.insert(10); // Duplicate '10' at tail
+        list.insert(30);
+
+        // Initial list state: [10, 20, 10, 30]
+        // Searching '10' hits the head immediately -> no re-linking
+        assertTrue(list.search(10));
+        assertEquals(10, list.getHeadValue());
+        assertEquals(4, list.getSize());
+
+        // Searching '20' moves middle element to head: [20, 10, 10, 30]
+        assertTrue(list.search(20));
+        assertEquals(20, list.getHeadValue());
+
+        // Searching '10' moves the FIRST instance of '10' (index 1) to head: [10, 20, 10, 30]
+        assertTrue(list.search(10));
+        assertEquals(10, list.getHeadValue());
+        assertEquals(4, list.getSize());
+    }
+}